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1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006 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. */
1817 {
1820 }
1822 {
1825 }
1833 {
1836 }
1838 {
1841 }
1844 /* 18For every pair of promoted integral types L and R, there exist candi-
1845 date operator functions of the form
1846 LR operator%(L, R);
1847 LR operator&(L, R);
1848 LR operator^(L, R);
1849 LR operator|(L, R);
1850 L operator<<(L, R);
1851 L operator>>(L, R);
1852 where LR is the result of the usual arithmetic conversions between
1853 types L and R. */
1865 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
1866 type, VQ is either volatile or empty, and R is a promoted arithmetic
1867 type, there exist candidate operator functions of the form
1868 VQ L& operator=(VQ L&, R);
1869 VQ L& operator*=(VQ L&, R);
1870 VQ L& operator/=(VQ L&, R);
1871 VQ L& operator+=(VQ L&, R);
1872 VQ L& operator-=(VQ L&, R);
1874 20For every pair T, VQ), where T is any type and VQ is either volatile
1875 or empty, there exist candidate operator functions of the form
1876 T*VQ& operator=(T*VQ&, T*);
1878 21For every pair T, VQ), where T is a pointer to member type and VQ is
1879 either volatile or empty, there exist candidate operator functions of
1880 the form
1881 VQ T& operator=(VQ T&, T);
1883 22For every triple T, VQ, I), where T is a cv-qualified or cv-
1884 unqualified complete object type, VQ is either volatile or empty, and
1885 I is a promoted integral type, there exist candidate operator func-
1886 tions of the form
1887 T*VQ& operator+=(T*VQ&, I);
1888 T*VQ& operator-=(T*VQ&, I);
1890 23For every triple L, VQ, R), where L is an integral or enumeration
1891 type, VQ is either volatile or empty, and R is a promoted integral
1892 type, there exist candidate operator functions of the form
1894 VQ L& operator%=(VQ L&, R);
1895 VQ L& operator<<=(VQ L&, R);
1896 VQ L& operator>>=(VQ L&, R);
1897 VQ L& operator&=(VQ L&, R);
1898 VQ L& operator^=(VQ L&, R);
1899 VQ L& operator|=(VQ L&, R); */
1903 {
1907 {
1910 }
1936 {
1939 }
1944 }
1949 /* [over.built]
1951 For every pair of promoted arithmetic types L and R, there
1952 exist candidate operator functions of the form
1954 LR operator?(bool, L, R);
1956 where LR is the result of the usual arithmetic conversions
1957 between types L and R.
1959 For every type T, where T is a pointer or pointer-to-member
1960 type, there exist candidate operator functions of the form T
1961 operator?(bool, T, T); */
1965 /* That's OK. */
1968 /* Otherwise, the types should be pointers. */
1973 /* We don't check that the two types are the same; the logic
1974 below will actually create two candidates; one in which both
1975 parameter types are TYPE1, and one in which both parameter
1976 types are TYPE2. */
1981 }
1983 /* If we're dealing with two pointer types or two enumeral types,
1984 we need candidates for both of them. */
1993 {
1994 build_builtin_candidate
1996 build_builtin_candidate
1999 }
2001 build_builtin_candidate
2003 }
2005 tree
2007 {
2013 }
2015 /* There are three conditions of builtin candidates:
2017 1) bool-taking candidates. These are the same regardless of the input.
2018 2) pointer-pair taking candidates. These are generated for each type
2019 one of the input types converts to.
2020 3) arithmetic candidates. According to the standard, we should generate
2021 all of these, but I'm trying not to...
2023 Here we generate a superset of the possible candidates for this particular
2024 case. That is a subset of the full set the standard defines, plus some
2025 other cases which the standard disallows. add_builtin_candidate will
2026 filter out the invalid set. */
2028 static void
2032 {
2036 /* TYPES[i] is the set of possible builtin-operator parameter types
2037 we will consider for the Ith argument. These are represented as
2038 a TREE_LIST; the TREE_VALUE of each node is the potential
2039 parameter type. */
2043 {
2046 else
2048 }
2051 {
2052 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2053 and VQ is either volatile or empty, there exist candidate operator
2054 functions of the form
2055 VQ T& operator++(VQ T&); */
2065 /* 24There also exist candidate operator functions of the form
2066 bool operator!(bool);
2067 bool operator&&(bool, bool);
2068 bool operator||(bool, bool); */
2071 build_builtin_candidate
2078 build_builtin_candidate
2096 /* Fall through. */
2100 }
2105 {
2107 ;
2109 {
2110 tree convs;
2118 {
2125 }
2131 {
2144 {
2150 }
2154 }
2155 }
2156 else
2157 {
2163 {
2169 }
2171 }
2172 }
2174 /* Run through the possible parameter types of both arguments,
2175 creating candidates with those parameter types. */
2177 {
2180 add_builtin_candidate
2183 else
2184 add_builtin_candidate
2187 }
2188 }
2191 /* If TMPL can be successfully instantiated as indicated by
2192 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2194 TMPL is the template. EXPLICIT_TARGS are any explicit template
2195 arguments. ARGLIST is the arguments provided at the call-site.
2196 The RETURN_TYPE is the desired type for conversion operators. If
2197 OBJ is NULL_TREE, FLAGS and CTYPE are as for add_function_candidate.
2198 If an OBJ is supplied, FLAGS and CTYPE are ignored, and OBJ is as for
2199 add_conv_candidate. */
2206 unification_kind_t strict)
2207 {
2213 tree fn;
2215 /* We don't do deduction on the in-charge parameter, the VTT
2216 parameter or 'this'. */
2226 args_without_in_chrg,
2236 /* In [class.copy]:
2238 A member function template is never instantiated to perform the
2239 copy of a class object to an object of its class type.
2241 It's a little unclear what this means; the standard explicitly
2242 does allow a template to be used to copy a class. For example,
2243 in:
2245 struct A {
2246 A(A&);
2247 template <class T> A(const T&);
2248 };
2249 const A f ();
2250 void g () { A a (f ()); }
2252 the member template will be used to make the copy. The section
2253 quoted above appears in the paragraph that forbids constructors
2254 whose only parameter is (a possibly cv-qualified variant of) the
2255 class type, and a logical interpretation is that the intent was
2256 to forbid the instantiation of member templates which would then
2257 have that form. */
2259 {
2262 ctype))
2264 }
2267 /* Aha, this is a conversion function. */
2270 else
2275 /* This situation can occur if a member template of a template
2276 class is specialized. Then, instantiate_template might return
2277 an instantiation of the specialization, in which case the
2278 DECL_TI_TEMPLATE field will point at the original
2279 specialization. For example:
2281 template <class T> struct S { template <class U> void f(U);
2282 template <> void f(int) {}; };
2283 S<double> sd;
2284 sd.f(3);
2286 Here, TMPL will be template <class U> S<double>::f(U).
2287 And, instantiate template will give us the specialization
2288 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2289 for this will point at template <class T> template <> S<T>::f(int),
2290 so that we can find the definition. For the purposes of
2291 overload resolution, however, we want the original TMPL. */
2293 else
2297 }
2304 unification_kind_t strict)
2305 {
2306 return
2311 }
2318 {
2319 return
2323 }
2325 /* The CANDS are the set of candidates that were considered for
2326 overload resolution. Return the set of viable candidates. If none
2327 of the candidates were viable, set *ANY_VIABLE_P to true. STRICT_P
2328 is true if a candidate should be considered viable only if it is
2329 strictly viable. */
2335 {
2346 {
2349 {
2355 }
2356 else
2358 }
2361 }
2363 static bool
2365 {
2370 }
2372 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2373 words, it is about to become the "this" pointer for a member
2374 function call. Take the address of the object. */
2376 static tree
2378 {
2379 /* In a template, we are only concerned about the type of the
2380 expression, so we can take a shortcut. */
2385 }
2387 /* Returns true iff functions are equivalent. Equivalent functions are
2388 not '==' only if one is a function-local extern function or if
2389 both are extern "C". */
2393 {
2398 }
2400 /* Print information about one overload candidate CANDIDATE. MSGSTR
2401 is the text to print before the candidate itself.
2403 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2404 to have been run through gettext by the caller. This wart makes
2405 life simpler in print_z_candidates and for the translators. */
2407 static void
2409 {
2411 {
2421 else
2424 }
2429 else
2431 }
2433 static void
2435 {
2440 /* There may be duplicates in the set of candidates. We put off
2441 checking this condition as long as possible, since we have no way
2442 to eliminate duplicates from a set of functions in less than n^2
2443 time. Now we are about to emit an error message, so it is more
2444 permissible to go slowly. */
2446 {
2448 /* Skip builtin candidates and conversion functions. */
2453 {
2457 else
2459 }
2460 }
2468 {
2469 /* Indent successive candidates by the width of the translation
2470 of the above string. */
2477 do
2478 {
2481 }
2483 }
2484 }
2486 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2487 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2488 the result of the conversion function to convert it to the final
2489 desired type. Merge the two sequences into a single sequence,
2490 and return the merged sequence. */
2494 {
2499 /* Find the end of the second conversion sequence. */
2504 /* Replace the identity conversion with the user conversion
2505 sequence. */
2508 /* The entire sequence is a user-conversion sequence. */
2512 }
2514 /* Returns the best overload candidate to perform the requested
2515 conversion. This function is used for three the overloading situations
2516 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2517 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2518 per [dcl.init.ref], so we ignore temporary bindings. */
2522 {
2531 /* We represent conversion within a hierarchy using RVALUE_CONV and
2532 BASE_CONV, as specified by [over.best.ics]; these become plain
2533 constructor calls, as specified in [dcl.init]. */
2547 {
2548 tree t;
2554 /* We should never try to call the abstract or base constructor
2555 from here. */
2559 }
2561 {
2571 flags,
2572 DEDUCE_CALL);
2573 else
2577 flags);
2581 }
2587 {
2588 tree fns;
2592 /* If we are called to convert to a reference type, we are trying to
2593 find an lvalue binding, so don't even consider temporaries. If
2594 we don't find an lvalue binding, the caller will try again to
2595 look for a temporary binding. */
2600 {
2603 /* [over.match.funcs] For conversion functions, the function
2604 is considered to be a member of the class of the implicit
2605 object argument for the purpose of defining the type of
2606 the implicit object parameter.
2608 So we pass fromtype as CTYPE to add_*_candidate. */
2612 NULL_TREE,
2615 conversion_path,
2616 flags,
2617 DEDUCE_CONV);
2618 else
2620 args,
2622 conversion_path,
2623 flags);
2626 {
2627 conversion *ics
2639 }
2640 }
2641 }
2649 {
2651 {
2655 }
2662 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
2663 ambiguous conversion is no worse than another user-defined
2664 conversion. */
2667 }
2669 /* Build the user conversion sequence. */
2670 conv = build_conv
2677 /* Combine it with the second conversion sequence. */
2685 }
2687 tree
2689 {
2694 {
2699 }
2701 }
2703 /* Do any initial processing on the arguments to a function call. */
2705 static tree
2707 {
2708 tree t;
2710 {
2716 {
2719 }
2722 }
2724 }
2726 /* Perform overload resolution on FN, which is called with the ARGS.
2728 Return the candidate function selected by overload resolution, or
2729 NULL if the event that overload resolution failed. In the case
2730 that overload resolution fails, *CANDIDATES will be the set of
2731 candidates considered, and ANY_VIABLE_P will be set to true or
2732 false to indicate whether or not any of the candidates were
2733 viable.
2735 The ARGS should already have gone through RESOLVE_ARGS before this
2736 function is called. */
2740 tree args,
2743 {
2751 /* Check FN and ARGS. */
2759 {
2763 }
2765 /* Add the various candidate functions. */
2769 LOOKUP_NORMAL,
2770 candidates);
2778 }
2780 /* Return an expression for a call to FN (a namespace-scope function,
2781 or a static member function) with the ARGS. */
2783 tree
2785 {
2789 tree result;
2795 /* If this function was found without using argument dependent
2796 lookup, then we want to ignore any undeclared friend
2797 functions. */
2799 {
2804 {
2808 }
2809 }
2811 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2817 {
2825 else
2831 }
2832 else
2835 /* Free all the conversions we allocated. */
2839 }
2841 /* Build a call to a global operator new. FNNAME is the name of the
2842 operator (either "operator new" or "operator new[]") and ARGS are
2843 the arguments provided. *SIZE points to the total number of bytes
2844 required by the allocation, and is updated if that is changed here.
2845 *COOKIE_SIZE is non-NULL if a cookie should be used. If this
2846 function determines that no cookie should be used, after all,
2847 *COOKIE_SIZE is set to NULL_TREE. If FN is non-NULL, it will be
2848 set, upon return, to the allocation function called. */
2850 tree
2854 {
2855 tree fns;
2867 /* Based on:
2869 [expr.new]
2871 If this lookup fails to find the name, or if the allocated type
2872 is not a class type, the allocation function's name is looked
2873 up in the global scope.
2875 we disregard block-scope declarations of "operator new". */
2878 /* Figure out what function is being called. */
2881 /* If no suitable function could be found, issue an error message
2882 and give up. */
2884 {
2888 else
2894 }
2896 /* If a cookie is required, add some extra space. Whether
2897 or not a cookie is required cannot be determined until
2898 after we know which function was called. */
2900 {
2903 {
2905 /* In G++ 3.2, the check was implemented incorrectly; it
2906 looked at the placement expression, rather than the
2907 type of the function. */
2910 ptr_type_node))
2912 }
2913 else
2914 {
2915 tree arg_types;
2918 /* Skip the size_t parameter. */
2920 /* Check the remaining parameters (if any). */
2924 ptr_type_node))
2926 }
2927 /* If we need a cookie, adjust the number of bytes allocated. */
2929 {
2930 /* Update the total size. */
2932 /* Update the argument list to reflect the adjusted size. */
2934 }
2935 else
2937 }
2939 /* Tell our caller which function we decided to call. */
2943 /* Build the CALL_EXPR. */
2945 }
2947 static tree
2949 {
2958 {
2959 /* It's no good looking for an overloaded operator() on a
2960 pointer-to-member-function. */
2961 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
2963 }
2966 {
2970 }
2971 else
2979 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2983 {
2988 {
2996 else
2997 add_function_candidate
3000 }
3001 }
3006 {
3018 {
3021 add_template_conv_candidate
3025 else
3029 }
3030 }
3034 {
3038 }
3039 else
3040 {
3043 {
3047 }
3048 /* Since cand->fn will be a type, not a function, for a conversion
3049 function, we must be careful not to unconditionally look at
3050 DECL_NAME here. */
3054 else
3055 {
3059 }
3060 }
3062 /* Free all the conversions we allocated. */
3066 }
3068 static void
3071 {
3076 else
3080 {
3104 else
3108 }
3109 }
3111 /* Return the implicit conversion sequence that could be used to
3112 convert E1 to E2 in [expr.cond]. */
3116 {
3122 /* [expr.cond]
3124 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3125 implicitly converted (clause _conv_) to the type "reference to
3126 T2", subject to the constraint that in the conversion the
3127 reference must bind directly (_dcl.init.ref_) to E1. */
3129 {
3131 t1,
3132 e1,
3134 LOOKUP_NO_TEMP_BIND);
3137 }
3139 /* [expr.cond]
3141 If E1 and E2 have class type, and the underlying class types are
3142 the same or one is a base class of the other: E1 can be converted
3143 to match E2 if the class of T2 is the same type as, or a base
3144 class of, the class of T1, and the cv-qualification of T2 is the
3145 same cv-qualification as, or a greater cv-qualification than, the
3146 cv-qualification of T1. If the conversion is applied, E1 is
3147 changed to an rvalue of type T2 that still refers to the original
3148 source class object (or the appropriate subobject thereof). */
3151 {
3153 {
3158 else
3161 }
3162 else
3164 }
3165 else
3166 /* [expr.cond]
3168 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3169 converted to the type that expression E2 would have if E2 were
3170 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3172 LOOKUP_NORMAL);
3173 }
3175 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3176 arguments to the conditional expression. */
3178 tree
3180 {
3181 tree arg2_type;
3182 tree arg3_type;
3190 /* As a G++ extension, the second argument to the conditional can be
3191 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3192 c'.) If the second operand is omitted, make sure it is
3193 calculated only once. */
3195 {
3199 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3202 else
3204 }
3206 /* [expr.cond]
3208 The first expr ession is implicitly converted to bool (clause
3209 _conv_). */
3212 /* If something has already gone wrong, just pass that fact up the
3213 tree. */
3219 /* [expr.cond]
3221 If either the second or the third operand has type (possibly
3222 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3223 array-to-pointer (_conv.array_), and function-to-pointer
3224 (_conv.func_) standard conversions are performed on the second
3225 and third operands. */
3233 {
3234 /* Do the conversions. We don't these for `void' type arguments
3235 since it can't have any effect and since decay_conversion
3236 does not handle that case gracefully. */
3244 /* [expr.cond]
3246 One of the following shall hold:
3248 --The second or the third operand (but not both) is a
3249 throw-expression (_except.throw_); the result is of the
3250 type of the other and is an rvalue.
3252 --Both the second and the third operands have type void; the
3253 result is of type void and is an rvalue.
3255 We must avoid calling force_rvalue for expressions of type
3256 "void" because it will complain that their value is being
3257 used. */
3260 {
3265 }
3268 {
3273 }
3276 else
3277 {
3281 }
3285 }
3286 /* [expr.cond]
3288 Otherwise, if the second and third operand have different types,
3289 and either has (possibly cv-qualified) class type, an attempt is
3290 made to convert each of those operands to the type of the other. */
3293 {
3297 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3303 /* [expr.cond]
3305 If both can be converted, or one can be converted but the
3306 conversion is ambiguous, the program is ill-formed. If
3307 neither can be converted, the operands are left unchanged and
3308 further checking is performed as described below. If exactly
3309 one conversion is possible, that conversion is applied to the
3310 chosen operand and the converted operand is used in place of
3311 the original operand for the remainder of this section. */
3316 {
3320 }
3322 {
3326 /* Even if CONV2 is a valid conversion, the result of the
3327 conversion may be invalid. For example, if ARG3 has type
3328 "volatile X", and X does not have a copy constructor
3329 accepting a "volatile X&", then even if ARG2 can be
3330 converted to X, the conversion will fail. */
3333 }
3335 {
3341 }
3343 /* Free all the conversions we allocated. */
3349 /* If, after the conversion, both operands have class type,
3350 treat the cv-qualification of both operands as if it were the
3351 union of the cv-qualification of the operands.
3353 The standard is not clear about what to do in this
3354 circumstance. For example, if the first operand has type
3355 "const X" and the second operand has a user-defined
3356 conversion to "volatile X", what is the type of the second
3357 operand after this step? Making it be "const X" (matching
3358 the first operand) seems wrong, as that discards the
3359 qualification without actually performing a copy. Leaving it
3360 as "volatile X" seems wrong as that will result in the
3361 conditional expression failing altogether, even though,
3362 according to this step, the one operand could be converted to
3363 the type of the other. */
3371 }
3373 /* [expr.cond]
3375 If the second and third operands are lvalues and have the same
3376 type, the result is of that type and is an lvalue. */
3380 {
3383 }
3385 /* [expr.cond]
3387 Otherwise, the result is an rvalue. If the second and third
3388 operand do not have the same type, and either has (possibly
3389 cv-qualified) class type, overload resolution is used to
3390 determine the conversions (if any) to be applied to the operands
3391 (_over.match.oper_, _over.built_). */
3395 {
3400 /* Rearrange the arguments so that add_builtin_candidate only has
3401 to know about two args. In build_builtin_candidates, the
3402 arguments are unscrambled. */
3407 COND_EXPR,
3408 NOP_EXPR,
3410 args,
3411 LOOKUP_NORMAL);
3413 /* [expr.cond]
3415 If the overload resolution fails, the program is
3416 ill-formed. */
3419 {
3423 }
3426 {
3430 }
3432 /* [expr.cond]
3434 Otherwise, the conversions thus determined are applied, and
3435 the converted operands are used in place of the original
3436 operands for the remainder of this section. */
3443 }
3445 /* [expr.cond]
3447 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3448 and function-to-pointer (_conv.func_) standard conversions are
3449 performed on the second and third operands.
3451 We need to force the lvalue-to-rvalue conversion here for class types,
3452 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3453 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3454 regions. */
3467 /* [expr.cond]
3469 After those conversions, one of the following shall hold:
3471 --The second and third operands have the same type; the result is of
3472 that type. */
3475 /* [expr.cond]
3477 --The second and third operands have arithmetic or enumeration
3478 type; the usual arithmetic conversions are performed to bring
3479 them to a common type, and the result is of that type. */
3484 {
3485 /* In this case, there is always a common type. */
3487 arg3_type);
3502 }
3503 /* [expr.cond]
3505 --The second and third operands have pointer type, or one has
3506 pointer type and the other is a null pointer constant; pointer
3507 conversions (_conv.ptr_) and qualification conversions
3508 (_conv.qual_) are performed to bring them to their composite
3509 pointer type (_expr.rel_). The result is of the composite
3510 pointer type.
3512 --The second and third operands have pointer to member type, or
3513 one has pointer to member type and the other is a null pointer
3514 constant; pointer to member conversions (_conv.mem_) and
3515 qualification conversions (_conv.qual_) are performed to bring
3516 them to a common type, whose cv-qualification shall match the
3517 cv-qualification of either the second or the third operand.
3518 The result is of the common type. */
3526 {
3533 }
3536 {
3540 }
3542 valid_operands:
3545 /* We can't use result_type below, as fold might have returned a
3546 throw_expr. */
3549 {
3550 /* Expand both sides into the same slot, hopefully the target of
3551 the ?: expression. We used to check for TARGET_EXPRs here,
3552 but now we sometimes wrap them in NOP_EXPRs so the test would
3553 fail. */
3556 /* If this expression is an rvalue, but might be mistaken for an
3557 lvalue, we must add a NON_LVALUE_EXPR. */
3559 }
3562 }
3564 /* OPERAND is an operand to an expression. Perform necessary steps
3565 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
3566 returned. */
3568 static tree
3570 {
3572 {
3575 /* Make sure the template type is instantiated now. */
3577 }
3580 }
3582 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
3583 OVERLOAD) to the CANDIDATES, returning an updated list of
3584 CANDIDATES. The ARGS are the arguments provided to the call,
3585 without any implicit object parameter. The EXPLICIT_TARGS are
3586 explicit template arguments provided. TEMPLATE_ONLY is true if
3587 only template functions should be considered. CONVERSION_PATH,
3588 ACCESS_PATH, and FLAGS are as for add_function_candidate. */
3590 static void
3596 {
3597 tree ctype;
3598 tree non_static_args;
3601 /* Delay creating the implicit this parameter until it is needed. */
3605 {
3606 tree fn;
3607 tree fn_args;
3610 /* Figure out which set of arguments to use. */
3612 {
3613 /* If this function is a non-static member, prepend the implicit
3614 object parameter. */
3620 }
3621 else
3622 /* Otherwise, just use the list of arguments provided. */
3627 fn,
3628 ctype,
3629 explicit_targs,
3630 fn_args,
3631 NULL_TREE,
3632 access_path,
3633 conversion_path,
3634 flags,
3635 DEDUCE_CALL);
3638 fn,
3639 ctype,
3640 fn_args,
3641 access_path,
3642 conversion_path,
3643 flags);
3645 }
3646 }
3648 tree
3651 {
3669 {
3673 }
3674 else
3680 {
3685 /* Use build_op_new_call and build_op_delete_call instead. */
3693 }
3699 {
3706 }
3721 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3724 /* Add namespace-scope operators to the list of functions to
3725 consider. */
3729 /* Add class-member operators to the candidate set. */
3731 {
3732 tree fns;
3736 {
3739 }
3746 }
3748 /* Rearrange the arguments for ?: so that add_builtin_candidate only has
3749 to know about two args; a builtin candidate will always have a first
3750 parameter of type bool. We'll handle that in
3751 build_builtin_candidate. */
3753 {
3757 }
3758 else
3759 {
3763 }
3768 {
3771 /* For these, the built-in candidates set is empty
3772 [over.match.oper]/3. We don't want non-strict matches
3773 because exact matches are always possible with built-in
3774 operators. The built-in candidate set for COMPONENT_REF
3775 would be empty too, but since there are no such built-in
3776 operators, we accept non-strict matches for them. */
3783 }
3787 {
3789 {
3792 /* Look for an `operator++ (int)'. If they didn't have
3793 one, then we fall back to the old way of doing things. */
3797 fnname,
3801 else
3804 overloaded_p);
3807 /* The caller will deal with these. */
3817 {
3820 }
3823 }
3824 }
3825 else
3826 {
3829 {
3831 {
3834 }
3836 }
3838 {
3843 }
3844 else
3845 {
3846 /* Give any warnings we noticed during overload resolution. */
3848 {
3852 }
3854 /* Check for comparison of different enum types. */
3856 {
3867 {
3870 }
3874 }
3876 /* We need to strip any leading REF_BIND so that bitfields
3877 don't cause errors. This should not remove any important
3878 conversions, because builtins don't apply to class
3879 objects directly. */
3885 {
3890 }
3892 {
3897 }
3898 }
3899 }
3901 user_defined_result_ready:
3903 /* Free all the conversions we allocated. */
3909 builtin:
3911 {
3961 /* The caller will deal with these. */
3969 }
3971 }
3973 /* Build a call to operator delete. This has to be handled very specially,
3974 because the restrictions on what signatures match are different from all
3975 other call instances. For a normal delete, only a delete taking (void *)
3976 or (void *, size_t) is accepted. For a placement delete, only an exact
3977 match with the placement new is accepted.
3979 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
3980 ADDR is the pointer to be deleted.
3981 SIZE is the size of the memory block to be deleted.
3982 GLOBAL_P is true if the delete-expression should not consider
3983 class-specific delete operators.
3984 PLACEMENT is the corresponding placement new call, or NULL_TREE.
3985 If PLACEMENT is non-NULL, then ALLOC_FN is the allocation function
3986 called to perform the placement new. */
3988 tree
3991 tree alloc_fn)
3992 {
4007 /* In [class.free]
4009 If the result of the lookup is ambiguous or inaccessible, or if
4010 the lookup selects a placement deallocation function, the
4011 program is ill-formed.
4013 Therefore, we ask lookup_fnfields to complain about ambiguity. */
4014 {
4018 }
4019 else
4026 {
4027 /* Get the parameter types for the allocation function that is
4028 being called. */
4031 /* Also the second argument. */
4033 }
4034 else
4035 {
4036 /* First try it without the size argument. */
4039 }
4041 /* Strip const and volatile from addr. */
4044 /* We make two tries at finding a matching `operator delete'. On
4045 the first pass, we look for a one-operator (or placement)
4046 operator delete. If we're not doing placement delete, then on
4047 the second pass we look for a two-argument delete. */
4049 {
4050 /* Go through the `operator delete' functions looking for one
4051 with a matching type. */
4053 fn;
4055 {
4056 tree t;
4058 /* The first argument must be "void *". */
4063 /* On the first pass, check the rest of the arguments. */
4065 {
4068 {
4073 }
4076 }
4077 /* On the second pass, the second argument must be
4078 "size_t". */
4083 }
4085 /* If we found a match, we're done. */
4088 }
4090 /* If we have a matching function, call it. */
4092 {
4093 /* Make sure we have the actual function, and not an
4094 OVERLOAD. */
4097 /* If the FN is a member function, make sure that it is
4098 accessible. */
4104 else
4109 {
4110 /* The placement args might not be suitable for overload
4111 resolution at this point, so build the call directly. */
4114 }
4115 else
4117 }
4119 /* If we are doing placement delete we do nothing if we don't find a
4120 matching op delete. */
4127 }
4129 /* If the current scope isn't allowed to access DECL along
4130 BASETYPE_PATH, give an error. The most derived class in
4131 BASETYPE_PATH is the one used to qualify DECL. */
4133 bool
4135 {
4139 {
4144 else
4148 }
4151 }
4153 /* Check that a callable constructor to initialize a temporary of
4154 TYPE from an EXPR exists. */
4156 static void
4158 {
4160 complete_ctor_identifier,
4162 type,
4163 LOOKUP_NORMAL | LOOKUP_ONLYCONVERTING
4164 | LOOKUP_NO_CONVERSION
4166 }
4168 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
4169 bitwise or of LOOKUP_* values. If any errors are warnings are
4170 generated, set *DIAGNOSTIC_FN to "error" or "warning",
4171 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
4172 to NULL. */
4174 static tree
4177 {
4182 complete_ctor_identifier,
4189 else
4192 }
4195 /* Perform the conversions in CONVS on the expression EXPR. FN and
4196 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4197 indicates the `this' argument of a method. INNER is nonzero when
4198 being called to continue a conversion chain. It is negative when a
4199 reference binding will be applied, positive otherwise. If
4200 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
4201 conversions will be emitted if appropriate. If C_CAST_P is true,
4202 this conversion is coming from a C-style cast; in that case,
4203 conversions to inaccessible bases are permitted. */
4205 static tree
4209 {
4211 diagnostic_fn_t diagnostic_fn;
4217 {
4220 {
4222 {
4227 }
4234 }
4239 }
4242 {
4245 /* Issue warnings about peculiar, but valid, uses of NULL. */
4247 {
4251 else
4253 }
4255 /* Warn about assigning a floating-point type to an integer type. */
4258 {
4262 else
4264 }
4265 }
4268 {
4270 {
4273 tree args;
4276 {
4281 /* We should never try to call the abstract or base constructor
4282 from here. */
4286 }
4287 else
4291 /* If this is a constructor or a function returning an aggr type,
4292 we need to build up a TARGET_EXPR. */
4296 /* The result of the call is then used to direct-initialize the object
4297 that is the destination of the copy-initialization. [dcl.init]
4299 Note that this step is not reflected in the conversion sequence;
4300 it affects the semantics when we actually perform the
4301 conversion, but is not considered during overload resolution.
4303 If the target is a class, that means call a ctor. */
4306 {
4307 expr = (build_temp
4309 /* Core issue 84, now a DR, says that we don't
4310 allow UDCs for these args (which deliberately
4311 breaks copy-init of an auto_ptr<Base> from an
4312 auto_ptr<Derived>). */
4317 {
4319 diagnostic_fn
4322 else
4323 diagnostic_fn
4325 }
4327 }
4329 }
4333 /* Convert a constant to its underlying value, unless we are
4334 about to bind it to a reference, in which case we need to
4335 leave it as an lvalue. */
4342 /* Call build_user_type_conversion again for the error. */
4343 return build_user_type_conversion
4348 };
4353 c_cast_p);
4358 {
4363 /* Else fall through. */
4366 {
4367 /* We are going to bind a reference directly to a base-class
4368 subobject of EXPR. */
4371 /* Build an expression for `*((base*) &expr)'. */
4377 }
4379 /* Copy-initialization where the cv-unqualified version of the source
4380 type is the same class as, or a derived class of, the class of the
4381 destination [is treated as direct-initialization]. [dcl.init] */
4389 {
4392 /* If necessary, create a temporary. */
4394 {
4399 {
4400 /* If the reference is volatile or non-const, we
4401 cannot create a temporary. */
4408 else
4411 }
4412 /* If the source is a packed field, and we must use a copy
4413 constructor, then building the target expr will require
4414 binding the field to the reference parameter to the
4415 copy constructor, and we'll end up with an infinite
4416 loop. If we can use a bitwise copy, then we'll be
4417 OK. */
4421 {
4425 }
4427 }
4429 /* Take the address of the thing to which we will bind the
4430 reference. */
4435 /* Convert it to a pointer to the type referred to by the
4436 reference. This will adjust the pointer if a derived to
4437 base conversion is being performed. */
4439 expr);
4440 /* Convert the pointer to the desired reference type. */
4442 }
4448 /* Warn about deprecated conversion if appropriate. */
4460 c_cast_p);
4464 }
4468 else
4472 }
4474 /* Build a call to __builtin_trap. */
4476 static tree
4478 {
4484 }
4486 /* ARG is being passed to a varargs function. Perform any conversions
4487 required. Return the converted value. */
4489 tree
4491 {
4492 /* [expr.call]
4494 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
4495 standard conversions are performed. */
4497 /* [expr.call]
4499 If the argument has integral or enumeration type that is subject
4500 to the integral promotions (_conv.prom_), or a floating point
4501 type that is subject to the floating point promotion
4502 (_conv.fpprom_), the value of the argument is converted to the
4503 promoted type before the call. */
4515 {
4516 /* Undefined behavior [expr.call] 5.2.2/7. We used to just warn
4517 here and do a bitwise copy, but now cp_expr_size will abort if we
4518 try to do that.
4519 If the call appears in the context of a sizeof expression,
4520 there is no need to emit a warning, since the expression won't be
4521 evaluated. We keep the builtin_trap just as a safety check. */
4527 integer_zero_node);
4528 }
4531 }
4533 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
4535 tree
4537 {
4547 {
4548 /* Remove reference types so we don't ICE later on. */
4550 /* Undefined behavior [expr.call] 5.2.2/7. */
4558 }
4561 }
4563 /* TYPE has been given to va_arg. Apply the default conversions which
4564 would have happened when passed via ellipsis. Return the promoted
4565 type, or the passed type if there is no change. */
4567 tree
4569 {
4570 tree promote;
4572 /* Perform the array-to-pointer and function-to-pointer
4573 conversions. */
4581 }
4583 /* ARG is a default argument expression being passed to a parameter of
4584 the indicated TYPE, which is a parameter to FN. Do any required
4585 conversions. Return the converted value. */
4587 tree
4589 {
4590 /* If the ARG is an unparsed default argument expression, the
4591 conversion cannot be performed. */
4593 {
4598 }
4606 {
4610 }
4611 else
4612 {
4613 /* This could get clobbered by the following call. */
4620 }
4623 }
4625 /* Returns the type which will really be used for passing an argument of
4626 type TYPE. */
4628 tree
4630 {
4631 /* Pass classes with copy ctors by invisible reference. */
4633 {
4635 /* There are no other pointers to this temporary. */
4637 }
4646 }
4648 /* Actually perform the appropriate conversion. */
4650 tree
4652 {
4654 ;
4655 /* Pass classes with copy ctors by invisible reference. */
4665 {
4674 }
4676 }
4678 /* Returns true iff FN is a function with magic varargs, i.e. ones for
4679 which no conversions at all should be done. This is true for some
4680 builtins which don't act like normal functions. */
4682 static bool
4684 {
4687 {
4696 }
4699 }
4701 /* Subroutine of the various build_*_call functions. Overload resolution
4702 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
4703 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
4704 bitmask of various LOOKUP_* flags which apply to the call itself. */
4706 static tree
4708 {
4719 /* In a template, there is no need to perform all of the work that
4720 is normally done. We are only interested in the type of the call
4721 expression, i.e., the return type of the function. Any semantic
4722 errors will be deferred until the template is instantiated. */
4724 {
4725 tree expr;
4726 tree return_type;
4734 }
4736 /* Give any warnings we noticed during overload resolution. */
4738 {
4742 }
4745 {
4746 /* If FN is a template function, two cases must be considered.
4747 For example:
4749 struct A {
4750 protected:
4751 template <class T> void f();
4752 };
4753 template <class T> struct B {
4754 protected:
4755 void g();
4756 };
4757 struct C : A, B<int> {
4758 using A::f; // #1
4759 using B<int>::g; // #2
4760 };
4762 In case #1 where `A::f' is a member template, DECL_ACCESS is
4763 recorded in the primary template but not in its specialization.
4764 We check access of FN using its primary template.
4766 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
4767 because it is a member of class template B, DECL_ACCESS is
4768 recorded in the specialization `B<int>::g'. We cannot use its
4769 primary template because `B<T>::g' and `B<int>::g' may have
4770 different access. */
4775 else
4777 }
4783 /* The implicit parameters to a constructor are not considered by overload
4784 resolution, and must be of the proper type. */
4786 {
4790 /* We should never try to call the abstract constructor. */
4794 {
4795 converted_args = tree_cons
4799 }
4800 }
4801 /* Bypass access control for 'this' parameter. */
4803 {
4806 tree converted_arg;
4807 tree base_binfo;
4813 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
4814 X is called for an object that is not of type X, or of a type
4815 derived from X, the behavior is undefined.
4817 So we can assume that anything passed as 'this' is non-null, and
4818 optimize accordingly. */
4820 /* Convert to the base in which the function was declared. */
4826 /* Check that the base class is accessible. */
4832 /* If fn was found by a using declaration, the conversion path
4833 will be to the derived class, not the base declaring fn. We
4834 must convert from derived to base. */
4845 }
4849 {
4854 /* Don't make a copy here if build_call is going to. */
4859 val = convert_like_with_context
4864 }
4866 /* Default arguments */
4868 converted_args
4873 converted_args);
4875 /* Ellipsis */
4877 {
4881 else
4884 }
4891 /* Avoid actually calling copy constructors and copy assignment operators,
4892 if possible. */
4897 {
4898 tree targ;
4902 /* Pull out the real argument, disregarding const-correctness. */
4909 {
4914 }
4915 else
4920 else
4923 /* [class.copy]: the copy constructor is implicitly defined even if
4924 the implementation elided its use. */
4928 /* If we're creating a temp and we already have one, don't create a
4929 new one. If we're not creating a temp but we get one, use
4930 INIT_EXPR to collapse the temp into our target. Otherwise, if the
4931 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
4932 temp or an INIT_EXPR otherwise. */
4934 {
4939 }
4942 {
4943 tree to = stabilize_reference
4948 }
4949 }
4953 {
4954 tree to = stabilize_reference
4961 {
4964 }
4965 else
4966 {
4967 /* We must only copy the non-tail padding parts.
4968 Use __builtin_memcpy for the bitwise copy. */
4981 }
4984 }
4989 {
5002 else
5005 }
5008 else
5012 }
5014 /* Build and return a call to FN, using ARGS. This function performs
5015 no overload resolution, conversion, or other high-level
5016 operations. */
5018 tree
5020 {
5021 tree fndecl;
5025 /* If this call might throw an exception, note that fact. */
5032 /* Some built-in function calls will be evaluated at compile-time in
5033 fold (). */
5046 }
5050 /* Make an expression which yields the address of the Java interface
5051 method FN. This is achieved by generating a call to libjava's
5052 _Jv_LookupInterfaceMethodIdx(). */
5054 static tree
5056 {
5062 {
5067 endlink)));
5068 java_iface_lookup_fn
5072 }
5074 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
5075 This is the first entry in the vtable. */
5077 integer_zero_node);
5079 /* Get the java.lang.Class pointer for the interface being called. */
5084 {
5086 iface);
5088 }
5092 /* Determine the itable index of FN. */
5095 {
5100 i++;
5101 }
5109 java_iface_lookup_fn);
5111 }
5113 /* Returns the value to use for the in-charge parameter when making a
5114 call to a function with the indicated NAME.
5116 FIXME:Can't we find a neater way to do this mapping? */
5118 tree
5120 {
5131 /* This function should only be called with one of the names listed
5132 above. */
5135 }
5137 /* Build a call to a constructor, destructor, or an assignment
5138 operator for INSTANCE, an expression with class type. NAME
5139 indicates the special member function to call; ARGS are the
5140 arguments. BINFO indicates the base of INSTANCE that is to be
5141 passed as the `this' parameter to the member function called.
5143 FLAGS are the LOOKUP_* flags to use when processing the call.
5145 If NAME indicates a complete object constructor, INSTANCE may be
5146 NULL_TREE. In this case, the caller will call build_cplus_new to
5147 store the newly constructed object into a VAR_DECL. */
5149 tree
5152 {
5153 tree fns;
5154 /* The type of the subobject to be constructed or destroyed. */
5155 tree class_type;
5164 {
5165 /* Resolve the name. */
5170 }
5176 /* Handle the special case where INSTANCE is NULL_TREE. */
5178 {
5181 }
5182 else
5183 {
5189 /* Convert to the base class, if necessary. */
5192 {
5194 /* For constructors and destructors, either the base is
5195 non-virtual, or it is virtual but we are doing the
5196 conversion from a constructor or destructor for the
5197 complete object. In either case, we can convert
5198 statically. */
5200 else
5201 /* However, for assignment operators, we must convert
5202 dynamically if the base is virtual. */
5205 }
5206 }
5212 /* When making a call to a constructor or destructor for a subobject
5213 that uses virtual base classes, pass down a pointer to a VTT for
5214 the subobject. */
5218 {
5219 tree vtt;
5220 tree sub_vtt;
5222 /* If the current function is a complete object constructor
5223 or destructor, then we fetch the VTT directly.
5224 Otherwise, we look it up using the VTT we were given. */
5230 current_vtt_parm,
5231 vtt);
5237 }
5242 }
5244 /* Return the NAME, as a C string. The NAME indicates a function that
5245 is a member of TYPE. *FREE_P is set to true if the caller must
5246 free the memory returned.
5248 Rather than go through all of this, we should simply set the names
5249 of constructors and destructors appropriately, and dispense with
5250 ctor_identifier, dtor_identifier, etc. */
5254 {
5257 /* Assume that we will not allocate memory. */
5259 /* Constructors and destructors are special. */
5261 {
5262 pretty_name
5264 /* For a destructor, add the '~'. */
5268 {
5270 /* Remember that we need to free the memory allocated. */
5272 }
5273 }
5275 {
5278 TFF_PLAIN_IDENTIFIER),
5279 NULL);
5280 /* Remember that we need to free the memory allocated. */
5282 }
5283 else
5287 }
5289 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
5290 be set, upon return, to the function called. */
5292 tree
5296 {
5300 tree access_binfo;
5301 tree optype;
5303 tree name;
5304 tree user_args;
5305 tree call;
5306 tree fn;
5307 tree class_type;
5310 tree orig_instance;
5311 tree orig_fns;
5312 tree orig_args;
5317 /* We don't know what function we're going to call, yet. */
5327 {
5330 }
5336 /* Dismantle the baselink to collect all the information we need. */
5343 {
5347 }
5358 {
5361 }
5363 /* The USER_ARGS are the arguments we will display to users if an
5364 error occurs. The USER_ARGS should not include any
5365 compiler-generated arguments. The "this" pointer hasn't been
5366 added yet. However, we must remove the VTT pointer if this is a
5367 call to a base-class constructor or destructor. */
5370 {
5371 /* Callers should explicitly indicate whether they want to construct
5372 the complete object or just the part without virtual bases. */
5374 /* Similarly for destructors. */
5376 /* Remove the VTT pointer, if present. */
5380 }
5382 /* Process the argument list. */
5389 /* It's OK to call destructors on cv-qualified objects. Therefore,
5390 convert the INSTANCE_PTR to the unqualified type, if necessary. */
5392 {
5397 }
5402 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5406 {
5408 tree this_arglist;
5410 /* We can end up here for copy-init of same or base class. */
5417 else
5421 /* A member template. */
5423 class_type,
5424 explicit_targs,
5426 access_binfo,
5427 conversion_path,
5428 flags,
5429 DEDUCE_CALL);
5432 class_type,
5433 this_arglist,
5434 access_binfo,
5435 conversion_path,
5436 flags);
5437 }
5441 {
5444 else
5445 {
5455 }
5458 }
5459 else
5460 {
5463 {
5469 user_args);
5474 }
5475 else
5476 {
5484 /* This is not an error, it is runtime undefined
5485 behavior. */
5487 "abstract virtual %q#D called from constructor"
5489 fn);
5493 {
5495 fn);
5497 }
5498 else
5499 {
5503 /* Now we know what function is being called. */
5506 /* Build the actual CALL_EXPR. */
5508 /* In an expression of the form `a->f()' where `f' turns
5509 out to be a static member function, `a' is
5510 none-the-less evaluated. */
5516 }
5517 }
5518 }
5521 call = (build_min_non_dep
5526 /* Free all the conversions we allocated. */
5530 }
5532 /* Returns true iff standard conversion sequence ICS1 is a proper
5533 subsequence of ICS2. */
5535 static bool
5537 {
5538 /* We can assume that a conversion of the same code
5539 between the same types indicates a subsequence since we only get
5540 here if the types we are converting from are the same. */
5547 {
5555 /* At this point, ICS1 cannot be a proper subsequence of
5556 ICS2. We can get a USER_CONV when we are comparing the
5557 second standard conversion sequence of two user conversion
5558 sequences. */
5568 }
5569 }
5571 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
5572 be any _TYPE nodes. */
5574 bool
5576 {
5581 /* We only allow proper derivation here. The DERIVED_FROM_P macro
5582 considers every class derived from itself. */
5585 }
5587 /* We build the ICS for an implicit object parameter as a pointer
5588 conversion sequence. However, such a sequence should be compared
5589 as if it were a reference conversion sequence. If ICS is the
5590 implicit conversion sequence for an implicit object parameter,
5591 modify it accordingly. */
5593 static void
5595 {
5597 {
5598 /* [over.match.funcs]
5600 For non-static member functions, the type of the
5601 implicit object parameter is "reference to cv X"
5602 where X is the class of which the function is a
5603 member and cv is the cv-qualification on the member
5604 function declaration. */
5606 tree reference_type;
5608 /* The `this' parameter is a pointer to a class type. Make the
5609 implicit conversion talk about a reference to that same class
5610 type. */
5621 }
5622 }
5624 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
5625 and return the type to which the reference refers. Otherwise,
5626 leave *ICS unchanged and return NULL_TREE. */
5628 static tree
5630 {
5632 {
5639 }
5642 }
5644 /* Compare two implicit conversion sequences according to the rules set out in
5645 [over.ics.rank]. Return values:
5647 1: ics1 is better than ics2
5648 -1: ics2 is better than ics1
5649 0: ics1 and ics2 are indistinguishable */
5651 static int
5653 {
5654 tree from_type1;
5655 tree from_type2;
5656 tree to_type1;
5657 tree to_type2;
5664 /* REF_BINDING is nonzero if the result of the conversion sequence
5665 is a reference type. In that case TARGET_TYPE is the
5666 type referred to by the reference. */
5667 tree target_type1;
5668 tree target_type2;
5670 /* Handle implicit object parameters. */
5674 /* Handle reference parameters. */
5678 /* [over.ics.rank]
5680 When comparing the basic forms of implicit conversion sequences (as
5681 defined in _over.best.ics_)
5683 --a standard conversion sequence (_over.ics.scs_) is a better
5684 conversion sequence than a user-defined conversion sequence
5685 or an ellipsis conversion sequence, and
5687 --a user-defined conversion sequence (_over.ics.user_) is a
5688 better conversion sequence than an ellipsis conversion sequence
5689 (_over.ics.ellipsis_). */
5699 {
5700 /* XXX Isn't this an extension? */
5701 /* Both ICS are bad. We try to make a decision based on what
5702 would have happened if they'd been good. */
5710 /* We couldn't make up our minds; try to figure it out below. */
5711 }
5714 /* Both conversions are ellipsis conversions. */
5717 /* User-defined conversion sequence U1 is a better conversion sequence
5718 than another user-defined conversion sequence U2 if they contain the
5719 same user-defined conversion operator or constructor and if the sec-
5720 ond standard conversion sequence of U1 is better than the second
5721 standard conversion sequence of U2. */
5724 {
5738 /* We can just fall through here, after setting up
5739 FROM_TYPE1 and FROM_TYPE2. */
5742 }
5743 else
5744 {
5748 /* We're dealing with two standard conversion sequences.
5750 [over.ics.rank]
5752 Standard conversion sequence S1 is a better conversion
5753 sequence than standard conversion sequence S2 if
5755 --S1 is a proper subsequence of S2 (comparing the conversion
5756 sequences in the canonical form defined by _over.ics.scs_,
5757 excluding any Lvalue Transformation; the identity
5758 conversion sequence is considered to be a subsequence of
5759 any non-identity conversion sequence */
5770 }
5773 {
5778 }
5779 /* Otherwise, one sequence cannot be a subsequence of the other; they
5780 don't start with the same type. This can happen when comparing the
5781 second standard conversion sequence in two user-defined conversion
5782 sequences. */
5784 /* [over.ics.rank]
5786 Or, if not that,
5788 --the rank of S1 is better than the rank of S2 (by the rules
5789 defined below):
5791 Standard conversion sequences are ordered by their ranks: an Exact
5792 Match is a better conversion than a Promotion, which is a better
5793 conversion than a Conversion.
5795 Two conversion sequences with the same rank are indistinguishable
5796 unless one of the following rules applies:
5798 --A conversion that is not a conversion of a pointer, or pointer
5799 to member, to bool is better than another conversion that is such
5800 a conversion.
5802 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
5803 so that we do not have to check it explicitly. */
5816 {
5821 }
5822 /* The rules for pointers to members A::* are just like the rules
5823 for pointers A*, except opposite: if B is derived from A then
5824 A::* converts to B::*, not vice versa. For that reason, we
5825 switch the from_ and to_ variables here. */
5832 {
5837 }
5842 {
5843 /* This was one of the pointer or pointer-like conversions.
5845 [over.ics.rank]
5847 --If class B is derived directly or indirectly from class A,
5848 conversion of B* to A* is better than conversion of B* to
5849 void*, and conversion of A* to void* is better than
5850 conversion of B* to void*. */
5853 {
5855 deref_from_type2))
5858 deref_from_type1))
5860 }
5863 {
5865 {
5867 {
5869 deref_to_type1))
5871 }
5872 /* We know that DEREF_TO_TYPE1 is `void' here. */
5874 deref_to_type2))
5876 }
5877 }
5880 {
5881 /* [over.ics.rank]
5883 --If class B is derived directly or indirectly from class A
5884 and class C is derived directly or indirectly from B,
5886 --conversion of C* to B* is better than conversion of C* to
5887 A*,
5889 --conversion of B* to A* is better than conversion of C* to
5890 A* */
5892 {
5894 deref_to_type2))
5897 deref_to_type1))
5899 }
5901 {
5903 deref_from_type1))
5906 deref_from_type2))
5908 }
5909 }
5910 }
5913 {
5916 /* [over.ics.rank]
5918 --binding of an expression of type C to a reference of type
5919 B& is better than binding an expression of type C to a
5920 reference of type A&
5922 --conversion of C to B is better than conversion of C to A, */
5925 {
5930 }
5931 }
5934 {
5937 /* [over.ics.rank]
5939 --binding of an expression of type B to a reference of type
5940 A& is better than binding an expression of type C to a
5941 reference of type A&,
5943 --conversion of B to A is better than conversion of C to A */
5946 {
5951 }
5952 }
5954 /* [over.ics.rank]
5956 --S1 and S2 differ only in their qualification conversion and yield
5957 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
5958 qualification signature of type T1 is a proper subset of the cv-
5959 qualification signature of type T2 */
5965 /* [over.ics.rank]
5967 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
5968 types to which the references refer are the same type except for
5969 top-level cv-qualifiers, and the type to which the reference
5970 initialized by S2 refers is more cv-qualified than the type to
5971 which the reference initialized by S1 refers */
5977 /* Neither conversion sequence is better than the other. */
5979 }
5981 /* The source type for this standard conversion sequence. */
5983 static tree
5985 {
5987 {
5992 }
5994 }
5996 /* Note a warning about preferring WINNER to LOSER. We do this by storing
5997 a pointer to LOSER and re-running joust to produce the warning if WINNER
5998 is actually used. */
6000 static void
6002 {
6008 }
6010 /* Compare two candidates for overloading as described in
6011 [over.match.best]. Return values:
6013 1: cand1 is better than cand2
6014 -1: cand2 is better than cand1
6015 0: cand1 and cand2 are indistinguishable */
6017 static int
6019 {
6025 /* Candidates that involve bad conversions are always worse than those
6026 that don't. */
6032 /* If we have two pseudo-candidates for conversions to the same type,
6033 or two candidates for the same function, arbitrarily pick one. */
6038 /* a viable function F1
6039 is defined to be a better function than another viable function F2 if
6040 for all arguments i, ICSi(F1) is not a worse conversion sequence than
6041 ICSi(F2), and then */
6043 /* for some argument j, ICSj(F1) is a better conversion sequence than
6044 ICSj(F2) */
6046 /* For comparing static and non-static member functions, we ignore
6047 the implicit object parameter of the non-static function. The
6048 standard says to pretend that the static function has an object
6049 parm, but that won't work with operator overloading. */
6052 {
6060 else
6061 {
6064 }
6065 }
6068 {
6074 {
6087 {
6094 else
6099 {
6103 }
6104 else
6106 }
6109 {
6112 }
6114 }
6115 }
6117 /* warn about confusing overload resolution for user-defined conversions,
6118 either between a constructor and a conversion op, or between two
6119 conversion ops. */
6123 {
6129 else
6132 /* We don't want to complain about `X::operator T1 ()'
6133 beating `X::operator T2 () const', when T2 is a no less
6134 cv-qualified version of T1. */
6137 {
6142 {
6145 }
6148 }
6149 else
6155 {
6163 }
6164 else
6166 }
6171 /* or, if not that,
6172 F1 is a non-template function and F2 is a template function
6173 specialization. */
6180 /* or, if not that,
6181 F1 and F2 are template functions and the function template for F1 is
6182 more specialized than the template for F2 according to the partial
6183 ordering rules. */
6186 {
6187 winner = more_specialized_fn
6190 /* [temp.func.order]: The presence of unused ellipsis and default
6191 arguments has no effect on the partial ordering of function
6192 templates. add_function_candidate() will not have
6193 counted the "this" argument for constructors. */
6197 }
6199 /* or, if not that,
6200 the context is an initialization by user-defined conversion (see
6201 _dcl.init_ and _over.match.user_) and the standard conversion
6202 sequence from the return type of F1 to the destination type (i.e.,
6203 the type of the entity being initialized) is a better conversion
6204 sequence than the standard conversion sequence from the return type
6205 of F2 to the destination type. */
6208 {
6212 }
6214 /* Check whether we can discard a builtin candidate, either because we
6215 have two identical ones or matching builtin and non-builtin candidates.
6217 (Pedantically in the latter case the builtin which matched the user
6218 function should not be added to the overload set, but we spot it here.
6220 [over.match.oper]
6221 ... the builtin candidates include ...
6222 - do not have the same parameter type list as any non-template
6223 non-member candidate. */
6227 {
6233 {
6235 /* Two built-in candidates; arbitrarily pick one. */
6238 /* cand1 is built-in; prefer cand2. */
6240 else
6241 /* cand2 is built-in; prefer cand1. */
6243 }
6244 }
6246 /* If the two functions are the same (this can happen with declarations
6247 in multiple scopes and arg-dependent lookup), arbitrarily choose one. */
6252 tweak:
6254 /* Extension: If the worst conversion for one candidate is worse than the
6255 worst conversion for the other, take the first. */
6257 {
6262 {
6267 }
6273 {
6275 {
6277 ISO C++ says that these are ambiguous, even \
6278 though the worst conversion for the first is better than \
6282 }
6283 else
6286 }
6287 }
6291 }
6293 /* Given a list of candidates for overloading, find the best one, if any.
6294 This algorithm has a worst case of O(2n) (winner is last), and a best
6295 case of O(n/2) (totally ambiguous); much better than a sorting
6296 algorithm. */
6300 {
6305 /* Walk through the list once, comparing each current champ to the next
6306 candidate, knocking out a candidate or two with each comparison. */
6309 {
6313 else
6314 {
6316 {
6321 }
6322 else
6323 {
6326 }
6329 }
6330 }
6332 /* Make sure the champ is better than all the candidates it hasn't yet
6333 been compared to. */
6336 challenger != champ
6339 {
6343 }
6346 }
6348 /* Returns nonzero if things of type FROM can be converted to TO. */
6350 bool
6352 {
6354 }
6356 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
6358 bool
6360 {
6365 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6369 flags);
6372 /* Free all the conversions we allocated. */
6376 }
6378 /* Like can_convert_arg, but allows dubious conversions as well. */
6380 bool
6382 {
6386 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6388 /* Try to perform the conversion. */
6390 LOOKUP_NORMAL);
6391 /* Free all the conversions we allocated. */
6395 }
6397 /* Convert EXPR to TYPE. Return the converted expression.
6399 Note that we allow bad conversions here because by the time we get to
6400 this point we are committed to doing the conversion. If we end up
6401 doing a bad conversion, convert_like will complain. */
6403 tree
6405 {
6412 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6417 LOOKUP_NORMAL);
6419 {
6422 }
6424 {
6425 /* In a template, we are only concerned about determining the
6426 type of non-dependent expressions, so we do not have to
6427 perform the actual conversion. */
6430 }
6431 else
6434 /* Free all the conversions we allocated. */
6438 }
6440 /* Convert EXPR to TYPE (as a direct-initialization) if that is
6441 permitted. If the conversion is valid, the converted expression is
6442 returned. Otherwise, NULL_TREE is returned, except in the case
6443 that TYPE is a class type; in that case, an error is issued. If
6444 C_CAST_P is true, then this direction initialization is taking
6445 place as part of a static_cast being attempted as part of a C-style
6446 cast. */
6448 tree
6450 tree expr,
6452 {
6458 /* [dcl.init]
6460 If the destination type is a (possibly cv-qualified) class type:
6462 -- If the initialization is direct-initialization ...,
6463 constructors are considered. ... If no constructor applies, or
6464 the overload resolution is ambiguous, the initialization is
6465 ill-formed. */
6467 {
6472 }
6474 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6478 c_cast_p,
6479 LOOKUP_NORMAL);
6482 else
6485 c_cast_p);
6487 /* Free all the conversions we allocated. */
6491 }
6493 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
6494 is being bound to a temporary. Create and return a new VAR_DECL
6495 with the indicated TYPE; this variable will store the value to
6496 which the reference is bound. */
6498 tree
6500 {
6501 tree var;
6503 /* Create the variable. */
6506 /* Register the variable. */
6508 {
6509 /* Namespace-scope or local static; give it a mangled name. */
6510 tree name;
6517 }
6518 else
6519 /* Create a new cleanup level if necessary. */
6523 }
6525 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
6526 initializing a variable of that TYPE. If DECL is non-NULL, it is
6527 the VAR_DECL being initialized with the EXPR. (In that case, the
6528 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
6529 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
6530 return, if *CLEANUP is no longer NULL, it will be an expression
6531 that should be pushed as a cleanup after the returned expression
6532 is used to initialize DECL.
6534 Return the converted expression. */
6536 tree
6538 {
6545 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6550 {
6556 else
6561 }
6563 /* If DECL is non-NULL, then this special rule applies:
6565 [class.temporary]
6567 The temporary to which the reference is bound or the temporary
6568 that is the complete object to which the reference is bound
6569 persists for the lifetime of the reference.
6571 The temporaries created during the evaluation of the expression
6572 initializing the reference, except the temporary to which the
6573 reference is bound, are destroyed at the end of the
6574 full-expression in which they are created.
6576 In that case, we store the converted expression into a new
6577 VAR_DECL in a new scope.
6579 However, we want to be careful not to create temporaries when
6580 they are not required. For example, given:
6582 struct B {};
6583 struct D : public B {};
6584 D f();
6585 const B& b = f();
6587 there is no need to copy the return value from "f"; we can just
6588 extend its lifetime. Similarly, given:
6590 struct S {};
6591 struct T { operator S(); };
6592 T t;
6593 const S& s = t;
6595 we can extend the lifetime of the return value of the conversion
6596 operator. */
6599 {
6600 tree var;
6601 tree base_conv_type;
6603 /* Skip over the REF_BIND. */
6605 /* If the next conversion is a BASE_CONV, skip that too -- but
6606 remember that the conversion was required. */
6608 {
6613 }
6614 else
6616 /* Perform the remainder of the conversion. */
6624 else
6625 {
6627 {
6628 tree init;
6629 tree type;
6631 /* Create the temporary variable. */
6635 /* If the rvalue is the result of a function call it will be
6636 a TARGET_EXPR. If it is some other construct (such as a
6637 member access expression where the underlying object is
6638 itself the result of a function call), turn it into a
6639 TARGET_EXPR here. It is important that EXPR be a
6640 TARGET_EXPR below since otherwise the INIT_EXPR will
6641 attempt to make a bitwise copy of EXPR to initialize
6642 VAR. */
6645 /* Create the INIT_EXPR that will initialize the temporary
6646 variable. */
6649 {
6653 /* We must be careful to destroy the temporary only
6654 after its initialization has taken place. If the
6655 initialization throws an exception, then the
6656 destructor should not be run. We cannot simply
6657 transform INIT into something like:
6659 (INIT, ({ CLEANUP_STMT; }))
6661 because emit_local_var always treats the
6662 initializer as a full-expression. Thus, the
6663 destructor would run too early; it would run at the
6664 end of initializing the reference variable, rather
6665 than at the end of the block enclosing the
6666 reference variable.
6668 The solution is to pass back a cleanup expression
6669 which the caller is responsible for attaching to
6670 the statement tree. */
6671 }
6672 else
6673 {
6677 static_aggregates);
6678 }
6679 /* Use its address to initialize the reference variable. */
6687 }
6688 else
6689 /* Take the address of EXPR. */
6691 /* If a BASE_CONV was required, perform it now. */
6693 expr = (perform_implicit_conversion
6696 }
6697 }
6698 else
6699 /* Perform the conversion. */
6702 /* Free all the conversions we allocated. */
6706 }