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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 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. */
43 /* The various kinds of conversion. */
46 ck_identity,
47 ck_lvalue,
48 ck_qual,
49 ck_std,
50 ck_ptr,
51 ck_pmem,
52 ck_base,
53 ck_ref_bind,
54 ck_user,
55 ck_ambig,
56 ck_rvalue
59 /* The rank of the conversion. Order of the enumerals matters; better
60 conversions should come earlier in the list. */
63 cr_identity,
64 cr_exact,
65 cr_promotion,
66 cr_std,
67 cr_pbool,
68 cr_user,
69 cr_ellipsis,
70 cr_bad
73 /* An implicit conversion sequence, in the sense of [over.best.ics].
74 The first conversion to be performed is at the end of the chain.
75 That conversion is always a cr_identity conversion. */
79 /* The kind of conversion represented by this step. */
80 conversion_kind kind;
81 /* The rank of this conversion. */
82 conversion_rank rank;
87 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
88 temporary should be created to hold the result of the
89 conversion. */
91 /* If KIND is ck_identity or ck_base_conv, true to indicate that the
92 copy constructor must be accessible, even though it is not being
93 used. */
95 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
96 from a pointer-to-derived to pointer-to-base is being performed. */
98 /* The type of the expression resulting from the conversion. */
99 tree type;
101 /* The next conversion in the chain. Since the conversions are
102 arranged from outermost to innermost, the NEXT conversion will
103 actually be performed before this conversion. This variant is
104 used only when KIND is neither ck_identity nor ck_ambig. */
106 /* The expression at the beginning of the conversion chain. This
107 variant is used only if KIND is ck_identity or ck_ambig. */
108 tree expr;
110 /* The function candidate corresponding to this conversion
111 sequence. This field is only used if KIND is ck_user. */
113 };
115 #define CONVERSION_RANK(NODE) \
116 ((NODE)->bad_p ? cr_bad \
117 : (NODE)->ellipsis_p ? cr_ellipsis \
118 : (NODE)->user_conv_p ? cr_user \
119 : (NODE)->rank)
130 #define convert_like(CONV, EXPR) \
131 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
134 #define convert_like_with_context(CONV, EXPR, FN, ARGNO) \
135 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
158 static void add_builtin_candidates
161 static void add_builtin_candidate
165 static void build_builtin_candidate
201 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
202 NAME can take many forms... */
204 bool
206 {
207 /* Just accept something we've already complained about. */
216 {
221 else
223 }
224 else
225 {
226 /* In the case of:
228 template <class T> struct S { ~S(); };
229 int i;
230 i.~S();
232 NAME will be a class template. */
235 }
240 }
242 /* We want the address of a function or method. We avoid creating a
243 pointer-to-member function. */
245 tree
247 {
250 /* We have to do these by hand to avoid real pointer to member
251 functions. */
253 {
255 {
259 }
261 }
262 else
266 }
268 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
269 POINTER_TYPE to those. Note, pointer to member function types
270 (TYPE_PTRMEMFUNC_P) must be handled by our callers. */
272 tree
274 {
277 tree tmp;
278 tree decl;
279 tree result_type;
280 tree fntype;
285 {
288 }
296 else
299 /* We check both the decl and the type; a function may be known not to
300 throw without being declared throw(). */
315 {
316 /* We invoke build_call directly for several library functions.
317 These may have been declared normally if we're building libgcc,
318 so we can't just check DECL_ARTIFICIAL. */
323 }
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. */
434 }
436 /* Returns nonzero if PARMLIST consists of only default parms and/or
437 ellipsis. */
439 bool
441 {
447 }
449 /* Allocate N bytes of memory from the conversion obstack. The memory
450 is zeroed before being returned. */
454 {
457 {
460 }
464 }
466 /* Dynamically allocate a conversion. */
470 {
475 }
477 #ifdef ENABLE_CHECKING
479 /* Make sure that all memory on the conversion obstack has been
480 freed. */
482 void
484 {
488 }
492 /* Dynamically allocate an array of N conversions. */
496 {
498 }
502 {
506 /* We can't use buildl1 here because CODE could be USER_CONV, which
507 takes two arguments. In that case, the caller is responsible for
508 filling in the second argument. */
514 {
530 }
536 }
538 /* Build a representation of the identity conversion from EXPR to
539 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
543 {
551 }
553 /* Converting from EXPR to TYPE was ambiguous in the sense that there
554 were multiple user-defined conversions to accomplish the job.
555 Build a conversion that indicates that ambiguity. */
559 {
567 }
569 tree
571 {
575 }
577 /* Returns the standard conversion path (see [conv]) from type FROM to type
578 TO, if any. For proper handling of null pointer constants, you must
579 also pass the expression EXPR to convert from. If C_CAST_P is true,
580 this conversion is coming from a C-style cast. */
585 {
592 {
595 }
601 {
606 }
613 {
617 }
619 {
623 }
627 /* Allow conversion between `__complex__' data types. */
629 {
630 /* The standard conversion sequence to convert FROM to TO is
631 the standard conversion sequence to perform componentwise
632 conversion. */
637 {
640 }
641 else
645 }
655 {
656 /* For backwards brain damage compatibility, allow interconversion of
657 pointers and integers with a pedwarn. */
660 }
662 {
663 /* For backwards brain damage compatibility, allow interconversion of
664 enums and integers with a pedwarn. */
667 }
670 {
671 tree to_pointee;
672 tree from_pointee;
677 ;
681 {
682 from = build_pointer_type
686 }
688 {
693 && (same_type_ignoring_top_level_qualifiers_p
696 {
700 }
703 }
706 /* [conv.ptr]
708 An rvalue of type "pointer to cv D," where D is a
709 class type, can be converted to an rvalue of type
710 "pointer to cv B," where B is a base class (clause
711 _class.derived_) of D. If B is an inaccessible
712 (clause _class.access_) or ambiguous
713 (_class.member.lookup_) base class of D, a program
714 that necessitates this conversion is ill-formed.
715 Therefore, we use DERIVED_FROM_P, and do not check
716 access or uniqueness. */
718 {
719 from =
725 }
728 {
731 }
732 else
733 {
736 }
741 /* In a C-style cast, we ignore CV-qualification because we
742 are allowed to perform a static_cast followed by a
743 const_cast. */
748 /* converting from string constant to char *. */
751 {
754 }
755 else
759 }
761 {
781 }
783 {
784 /* [conv.bool]
786 An rvalue of arithmetic, enumeration, pointer, or pointer to
787 member type can be converted to an rvalue of type bool. */
792 {
800 }
803 }
804 /* We don't check for ENUMERAL_TYPE here because there are no standard
805 conversions to enum type. */
808 {
813 /* Give this a better rank if it's a promotion. */
817 }
824 {
828 /* The derived-to-base conversion indicates the initialization
829 of a parameter with base type from an object of a derived
830 type. A temporary object is created to hold the result of
831 the conversion. */
833 }
834 else
838 }
840 /* Returns nonzero if T1 is reference-related to T2. */
842 static bool
844 {
848 /* [dcl.init.ref]
850 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
851 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
852 of T2. */
856 }
858 /* Returns nonzero if T1 is reference-compatible with T2. */
860 static bool
862 {
863 /* [dcl.init.ref]
865 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
866 reference-related to T2 and cv1 is the same cv-qualification as,
867 or greater cv-qualification than, cv2. */
870 }
872 /* Determine whether or not the EXPR (of class type S) can be
873 converted to T as in [over.match.ref]. */
877 {
878 tree conversions;
879 tree arglist;
881 tree reference_type;
890 /* [over.match.ref]
892 Assuming that "cv1 T" is the underlying type of the reference
893 being initialized, and "cv S" is the type of the initializer
894 expression, with S a class type, the candidate functions are
895 selected as follows:
897 --The conversion functions of S and its base classes are
898 considered. Those that are not hidden within S and yield type
899 "reference to cv2 T2", where "cv1 T" is reference-compatible
900 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
902 The argument list has one argument, which is the initializer
903 expression. */
907 /* Conceptually, we should take the address of EXPR and put it in
908 the argument list. Unfortunately, however, that can result in
909 error messages, which we should not issue now because we are just
910 trying to find a conversion operator. Therefore, we use NULL,
911 cast to the appropriate type. */
918 {
922 {
928 /* If this is a template function, try to get an exact
929 match. */
931 {
934 NULL_TREE,
935 arglist,
936 reference_type,
939 LOOKUP_NORMAL,
940 DEDUCE_CONV);
943 {
944 /* Now, see if the conversion function really returns
945 an lvalue of the appropriate type. From the
946 point of view of unification, simply returning an
947 rvalue of the right type is good enough. */
952 {
955 }
956 }
957 }
963 LOOKUP_NORMAL);
966 {
968 /* Build a standard conversion sequence indicating the
969 binding from the reference type returned by the
970 function to the desired REFERENCE_TYPE. */
971 identity_conv
974 NULL_TREE);
975 cand->second_conv
976 = (direct_reference_binding
979 }
980 }
982 }
985 /* If none of the conversion functions worked out, let our caller
986 know. */
994 /* Now that we know that this is the function we're going to use fix
995 the dummy first argument. */
1000 /* Build a user-defined conversion sequence representing the
1001 conversion. */
1007 /* Merge it with the standard conversion sequence from the
1008 conversion function's return type to the desired type. */
1015 }
1017 /* A reference of the indicated TYPE is being bound directly to the
1018 expression represented by the implicit conversion sequence CONV.
1019 Return a conversion sequence for this binding. */
1023 {
1024 tree t;
1031 /* [over.ics.rank]
1033 When a parameter of reference type binds directly
1034 (_dcl.init.ref_) to an argument expression, the implicit
1035 conversion sequence is the identity conversion, unless the
1036 argument expression has a type that is a derived class of the
1037 parameter type, in which case the implicit conversion sequence is
1038 a derived-to-base Conversion.
1040 If the parameter binds directly to the result of applying a
1041 conversion function to the argument expression, the implicit
1042 conversion sequence is a user-defined conversion sequence
1043 (_over.ics.user_), with the second standard conversion sequence
1044 either an identity conversion or, if the conversion function
1045 returns an entity of a type that is a derived class of the
1046 parameter type, a derived-to-base conversion. */
1048 {
1049 /* Represent the derived-to-base conversion. */
1051 /* We will actually be binding to the base-class subobject in
1052 the derived class, so we mark this conversion appropriately.
1053 That way, convert_like knows not to generate a temporary. */
1055 }
1057 }
1059 /* Returns the conversion path from type FROM to reference type TO for
1060 purposes of reference binding. For lvalue binding, either pass a
1061 reference type to FROM or an lvalue expression to EXPR. If the
1062 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1063 the conversion returned. If C_CAST_P is true, this
1064 conversion is coming from a C-style cast. */
1068 {
1077 {
1082 }
1085 {
1086 /* Anything with reference type is an lvalue. */
1089 }
1093 /* Figure out whether or not the types are reference-related and
1094 reference compatible. We have do do this after stripping
1095 references from FROM. */
1097 /* If this is a C cast, first convert to an appropriately qualified
1098 type, so that we can later do a const_cast to the desired type. */
1105 {
1106 /* [dcl.init.ref]
1108 If the initializer expression
1110 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1111 is reference-compatible with "cv2 T2,"
1113 the reference is bound directly to the initializer expression
1114 lvalue. */
1119 /* For the purposes of overload resolution, we ignore the fact
1120 this expression is a bitfield or packed field. (In particular,
1121 [over.ics.ref] says specifically that a function with a
1122 non-const reference parameter is viable even if the
1123 argument is a bitfield.)
1125 However, when we actually call the function we must create
1126 a temporary to which to bind the reference. If the
1127 reference is volatile, or isn't const, then we cannot make
1128 a temporary, so we just issue an error when the conversion
1129 actually occurs. */
1133 }
1135 {
1136 /* [dcl.init.ref]
1138 If the initializer expression
1140 -- has a class type (i.e., T2 is a class type) can be
1141 implicitly converted to an lvalue of type "cv3 T3," where
1142 "cv1 T1" is reference-compatible with "cv3 T3". (this
1143 conversion is selected by enumerating the applicable
1144 conversion functions (_over.match.ref_) and choosing the
1145 best one through overload resolution. (_over.match_).
1147 the reference is bound to the lvalue result of the conversion
1148 in the second case. */
1152 }
1154 /* From this point on, we conceptually need temporaries, even if we
1155 elide them. Only the cases above are "direct bindings". */
1159 /* [over.ics.rank]
1161 When a parameter of reference type is not bound directly to an
1162 argument expression, the conversion sequence is the one required
1163 to convert the argument expression to the underlying type of the
1164 reference according to _over.best.ics_. Conceptually, this
1165 conversion sequence corresponds to copy-initializing a temporary
1166 of the underlying type with the argument expression. Any
1167 difference in top-level cv-qualification is subsumed by the
1168 initialization itself and does not constitute a conversion. */
1170 /* [dcl.init.ref]
1172 Otherwise, the reference shall be to a non-volatile const type. */
1176 /* [dcl.init.ref]
1178 If the initializer expression is an rvalue, with T2 a class type,
1179 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1180 is bound in one of the following ways:
1182 -- The reference is bound to the object represented by the rvalue
1183 or to a sub-object within that object.
1185 -- ...
1187 We use the first alternative. The implicit conversion sequence
1188 is supposed to be same as we would obtain by generating a
1189 temporary. Fortunately, if the types are reference compatible,
1190 then this is either an identity conversion or the derived-to-base
1191 conversion, just as for direct binding. */
1193 {
1199 }
1201 /* [dcl.init.ref]
1203 Otherwise, a temporary of type "cv1 T1" is created and
1204 initialized from the initializer expression using the rules for a
1205 non-reference copy initialization. If T1 is reference-related to
1206 T2, cv1 must be the same cv-qualification as, or greater
1207 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1212 flags);
1217 /* This reference binding, unlike those above, requires the
1218 creation of a temporary. */
1222 }
1224 /* Returns the implicit conversion sequence (see [over.ics]) from type
1225 FROM to type TO. The optional expression EXPR may affect the
1226 conversion. FLAGS are the usual overloading flags. Only
1227 LOOKUP_NO_CONVERSION is significant. If C_CAST_P is true, this
1228 conversion is coming from a C-style cast. */
1233 {
1242 else
1252 {
1255 cand = build_user_type_conversion_1
1260 /* We used to try to bind a reference to a temporary here, but that
1261 is now handled by the recursive call to this function at the end
1262 of reference_binding. */
1264 }
1267 }
1269 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1270 functions. */
1278 {
1293 }
1295 /* Create an overload candidate for the function or method FN called with
1296 the argument list ARGLIST and add it to CANDIDATES. FLAGS is passed on
1297 to implicit_conversion.
1299 CTYPE, if non-NULL, is the type we want to pretend this function
1300 comes from for purposes of overload resolution. */
1307 {
1312 tree orig_arglist;
1315 /* At this point we should not see any functions which haven't been
1316 explicitly declared, except for friend functions which will have
1317 been found using argument dependent lookup. */
1320 /* The `this', `in_chrg' and VTT arguments to constructors are not
1321 considered in overload resolution. */
1323 {
1327 }
1328 else
1334 /* 13.3.2 - Viable functions [over.match.viable]
1335 First, to be a viable function, a candidate function shall have enough
1336 parameters to agree in number with the arguments in the list.
1338 We need to check this first; otherwise, checking the ICSes might cause
1339 us to produce an ill-formed template instantiation. */
1343 {
1347 }
1352 /* Make sure there are default args for the rest of the parms. */
1359 /* Second, for F to be a viable function, there shall exist for each
1360 argument an implicit conversion sequence that converts that argument
1361 to the corresponding parameter of F. */
1367 {
1380 {
1383 /* The type of the implicit object parameter ('this') for
1384 overload resolution is not always the same as for the
1385 function itself; conversion functions are considered to
1386 be members of the class being converted, and functions
1387 introduced by a using-declaration are considered to be
1388 members of the class that uses them.
1390 Since build_over_call ignores the ICS for the `this'
1391 parameter, we can just change the parm type. */
1393 {
1394 parmtype
1398 }
1402 }
1403 else
1404 {
1407 }
1414 {
1417 }
1425 }
1427 out:
1430 }
1432 /* Create an overload candidate for the conversion function FN which will
1433 be invoked for expression OBJ, producing a pointer-to-function which
1434 will in turn be called with the argument list ARGLIST, and add it to
1435 CANDIDATES. FLAGS is passed on to implicit_conversion.
1437 Actually, we don't really care about FN; we care about the type it
1438 converts to. There may be multiple conversion functions that will
1439 convert to that type, and we rely on build_user_type_conversion_1 to
1440 choose the best one; so when we create our candidate, we record the type
1441 instead of the function. */
1446 {
1463 /* Don't bother looking up the same type twice. */
1468 {
1475 flags);
1481 else
1482 {
1485 }
1500 }
1510 }
1512 static void
1516 {
1530 {
1537 {
1539 /* We need something for printing the candidate. */
1541 }
1545 }
1547 /* For COND_EXPR we rearranged the arguments; undo that now. */
1549 {
1556 else
1558 }
1564 viable);
1565 }
1567 static bool
1569 {
1571 }
1573 /* Returns nonzero if TYPE is a promoted arithmetic type. */
1575 static bool
1577 {
1578 /* [over.built]
1580 In this section, the term promoted integral type is used to refer
1581 to those integral types which are preserved by integral promotion
1582 (including e.g. int and long but excluding e.g. char).
1583 Similarly, the term promoted arithmetic type refers to promoted
1584 integral types plus floating types. */
1588 }
1590 /* Create any builtin operator overload candidates for the operator in
1591 question given the converted operand types TYPE1 and TYPE2. The other
1592 args are passed through from add_builtin_candidates to
1593 build_builtin_candidate.
1595 TYPE1 and TYPE2 may not be permissible, and we must filter them.
1596 If CODE is requires candidates operands of the same type of the kind
1597 of which TYPE1 and TYPE2 are, we add both candidates
1598 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
1600 static void
1604 {
1606 {
1614 }
1617 {
1619 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
1620 and VQ is either volatile or empty, there exist candidate operator
1621 functions of the form
1622 VQ T& operator++(VQ T&);
1623 T operator++(VQ T&, int);
1624 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
1625 type other than bool, and VQ is either volatile or empty, there exist
1626 candidate operator functions of the form
1627 VQ T& operator--(VQ T&);
1628 T operator--(VQ T&, int);
1629 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
1630 complete object type, and VQ is either volatile or empty, there exist
1631 candidate operator functions of the form
1632 T*VQ& operator++(T*VQ&);
1633 T*VQ& operator--(T*VQ&);
1634 T* operator++(T*VQ&, int);
1635 T* operator--(T*VQ&, int); */
1644 {
1647 }
1650 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
1651 exist candidate operator functions of the form
1653 T& operator*(T*);
1655 8 For every function type T, there exist candidate operator functions of
1656 the form
1657 T& operator*(T*); */
1666 /* 9 For every type T, there exist candidate operator functions of the form
1667 T* operator+(T*);
1669 10For every promoted arithmetic type T, there exist candidate operator
1670 functions of the form
1671 T operator+(T);
1672 T operator-(T); */
1682 /* 11For every promoted integral type T, there exist candidate operator
1683 functions of the form
1684 T operator~(T); */
1691 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
1692 is the same type as C2 or is a derived class of C2, T is a complete
1693 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
1694 there exist candidate operator functions of the form
1695 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
1696 where CV12 is the union of CV1 and CV2. */
1701 {
1709 }
1712 /* 13For every pair of promoted arithmetic types L and R, there exist can-
1713 didate operator functions of the form
1714 LR operator*(L, R);
1715 LR operator/(L, R);
1716 LR operator+(L, R);
1717 LR operator-(L, R);
1718 bool operator<(L, R);
1719 bool operator>(L, R);
1720 bool operator<=(L, R);
1721 bool operator>=(L, R);
1722 bool operator==(L, R);
1723 bool operator!=(L, R);
1724 where LR is the result of the usual arithmetic conversions between
1725 types L and R.
1727 14For every pair of types T and I, where T is a cv-qualified or cv-
1728 unqualified complete object type and I is a promoted integral type,
1729 there exist candidate operator functions of the form
1730 T* operator+(T*, I);
1731 T& operator[](T*, I);
1732 T* operator-(T*, I);
1733 T* operator+(I, T*);
1734 T& operator[](I, T*);
1736 15For every T, where T is a pointer to complete object type, there exist
1737 candidate operator functions of the form112)
1738 ptrdiff_t operator-(T, T);
1740 16For every pointer or enumeration type T, there exist candidate operator
1741 functions of the form
1742 bool operator<(T, T);
1743 bool operator>(T, T);
1744 bool operator<=(T, T);
1745 bool operator>=(T, T);
1746 bool operator==(T, T);
1747 bool operator!=(T, T);
1749 17For every pointer to member type T, there exist candidate operator
1750 functions of the form
1751 bool operator==(T, T);
1752 bool operator!=(T, T); */
1758 {
1761 }
1774 {
1777 }
1779 {
1782 }
1783 /* Fall through. */
1800 {
1803 }
1807 {
1810 }
1818 {
1821 }
1823 {
1826 }
1829 /* 18For every pair of promoted integral types L and R, there exist candi-
1830 date operator functions of the form
1831 LR operator%(L, R);
1832 LR operator&(L, R);
1833 LR operator^(L, R);
1834 LR operator|(L, R);
1835 L operator<<(L, R);
1836 L operator>>(L, R);
1837 where LR is the result of the usual arithmetic conversions between
1838 types L and R. */
1850 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
1851 type, VQ is either volatile or empty, and R is a promoted arithmetic
1852 type, there exist candidate operator functions of the form
1853 VQ L& operator=(VQ L&, R);
1854 VQ L& operator*=(VQ L&, R);
1855 VQ L& operator/=(VQ L&, R);
1856 VQ L& operator+=(VQ L&, R);
1857 VQ L& operator-=(VQ L&, R);
1859 20For every pair T, VQ), where T is any type and VQ is either volatile
1860 or empty, there exist candidate operator functions of the form
1861 T*VQ& operator=(T*VQ&, T*);
1863 21For every pair T, VQ), where T is a pointer to member type and VQ is
1864 either volatile or empty, there exist candidate operator functions of
1865 the form
1866 VQ T& operator=(VQ T&, T);
1868 22For every triple T, VQ, I), where T is a cv-qualified or cv-
1869 unqualified complete object type, VQ is either volatile or empty, and
1870 I is a promoted integral type, there exist candidate operator func-
1871 tions of the form
1872 T*VQ& operator+=(T*VQ&, I);
1873 T*VQ& operator-=(T*VQ&, I);
1875 23For every triple L, VQ, R), where L is an integral or enumeration
1876 type, VQ is either volatile or empty, and R is a promoted integral
1877 type, there exist candidate operator functions of the form
1879 VQ L& operator%=(VQ L&, R);
1880 VQ L& operator<<=(VQ L&, R);
1881 VQ L& operator>>=(VQ L&, R);
1882 VQ L& operator&=(VQ L&, R);
1883 VQ L& operator^=(VQ L&, R);
1884 VQ L& operator|=(VQ L&, R); */
1888 {
1892 {
1895 }
1921 {
1924 }
1929 }
1934 /* [over.built]
1936 For every pair of promoted arithmetic types L and R, there
1937 exist candidate operator functions of the form
1939 LR operator?(bool, L, R);
1941 where LR is the result of the usual arithmetic conversions
1942 between types L and R.
1944 For every type T, where T is a pointer or pointer-to-member
1945 type, there exist candidate operator functions of the form T
1946 operator?(bool, T, T); */
1950 /* That's OK. */
1953 /* Otherwise, the types should be pointers. */
1958 /* We don't check that the two types are the same; the logic
1959 below will actually create two candidates; one in which both
1960 parameter types are TYPE1, and one in which both parameter
1961 types are TYPE2. */
1966 }
1968 /* If we're dealing with two pointer types or two enumeral types,
1969 we need candidates for both of them. */
1978 {
1979 build_builtin_candidate
1981 build_builtin_candidate
1984 }
1986 build_builtin_candidate
1988 }
1990 tree
1992 {
1998 }
2000 /* There are three conditions of builtin candidates:
2002 1) bool-taking candidates. These are the same regardless of the input.
2003 2) pointer-pair taking candidates. These are generated for each type
2004 one of the input types converts to.
2005 3) arithmetic candidates. According to the standard, we should generate
2006 all of these, but I'm trying not to...
2008 Here we generate a superset of the possible candidates for this particular
2009 case. That is a subset of the full set the standard defines, plus some
2010 other cases which the standard disallows. add_builtin_candidate will
2011 filter out the invalid set. */
2013 static void
2017 {
2021 /* TYPES[i] is the set of possible builtin-operator parameter types
2022 we will consider for the Ith argument. These are represented as
2023 a TREE_LIST; the TREE_VALUE of each node is the potential
2024 parameter type. */
2028 {
2031 else
2033 }
2036 {
2037 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2038 and VQ is either volatile or empty, there exist candidate operator
2039 functions of the form
2040 VQ T& operator++(VQ T&); */
2050 /* 24There also exist candidate operator functions of the form
2051 bool operator!(bool);
2052 bool operator&&(bool, bool);
2053 bool operator||(bool, bool); */
2056 build_builtin_candidate
2063 build_builtin_candidate
2081 /* Fall through. */
2085 }
2090 {
2092 ;
2094 {
2095 tree convs;
2103 {
2110 }
2116 {
2129 {
2135 }
2139 }
2140 }
2141 else
2142 {
2148 {
2154 }
2156 }
2157 }
2159 /* Run through the possible parameter types of both arguments,
2160 creating candidates with those parameter types. */
2162 {
2165 add_builtin_candidate
2168 else
2169 add_builtin_candidate
2172 }
2175 }
2178 /* If TMPL can be successfully instantiated as indicated by
2179 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2181 TMPL is the template. EXPLICIT_TARGS are any explicit template
2182 arguments. ARGLIST is the arguments provided at the call-site.
2183 The RETURN_TYPE is the desired type for conversion operators. If
2184 OBJ is NULL_TREE, FLAGS and CTYPE are as for add_function_candidate.
2185 If an OBJ is supplied, FLAGS and CTYPE are ignored, and OBJ is as for
2186 add_conv_candidate. */
2193 unification_kind_t strict)
2194 {
2200 tree fn;
2202 /* We don't do deduction on the in-charge parameter, the VTT
2203 parameter or 'this'. */
2213 args_without_in_chrg,
2223 /* In [class.copy]:
2225 A member function template is never instantiated to perform the
2226 copy of a class object to an object of its class type.
2228 It's a little unclear what this means; the standard explicitly
2229 does allow a template to be used to copy a class. For example,
2230 in:
2232 struct A {
2233 A(A&);
2234 template <class T> A(const T&);
2235 };
2236 const A f ();
2237 void g () { A a (f ()); }
2239 the member template will be used to make the copy. The section
2240 quoted above appears in the paragraph that forbids constructors
2241 whose only parameter is (a possibly cv-qualified variant of) the
2242 class type, and a logical interpretation is that the intent was
2243 to forbid the instantiation of member templates which would then
2244 have that form. */
2246 {
2249 ctype))
2251 }
2254 /* Aha, this is a conversion function. */
2257 else
2262 /* This situation can occur if a member template of a template
2263 class is specialized. Then, instantiate_template might return
2264 an instantiation of the specialization, in which case the
2265 DECL_TI_TEMPLATE field will point at the original
2266 specialization. For example:
2268 template <class T> struct S { template <class U> void f(U);
2269 template <> void f(int) {}; };
2270 S<double> sd;
2271 sd.f(3);
2273 Here, TMPL will be template <class U> S<double>::f(U).
2274 And, instantiate template will give us the specialization
2275 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2276 for this will point at template <class T> template <> S<T>::f(int),
2277 so that we can find the definition. For the purposes of
2278 overload resolution, however, we want the original TMPL. */
2280 else
2284 }
2291 unification_kind_t strict)
2292 {
2293 return
2298 }
2305 {
2306 return
2310 }
2312 /* The CANDS are the set of candidates that were considered for
2313 overload resolution. Return the set of viable candidates. If none
2314 of the candidates were viable, set *ANY_VIABLE_P to true. STRICT_P
2315 is true if a candidate should be considered viable only if it is
2316 strictly viable. */
2322 {
2333 {
2336 {
2342 }
2343 else
2345 }
2348 }
2350 static bool
2352 {
2357 }
2359 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2360 words, it is about to become the "this" pointer for a member
2361 function call. Take the address of the object. */
2363 static tree
2365 {
2366 /* In a template, we are only concerned about the type of the
2367 expression, so we can take a shortcut. */
2372 }
2374 /* Returns true iff functions are equivalent. Equivalent functions are
2375 not '==' only if one is a function-local extern function or if
2376 both are extern "C". */
2380 {
2385 }
2387 /* Print information about one overload candidate CANDIDATE. MSGSTR
2388 is the text to print before the candidate itself.
2390 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2391 to have been run through gettext by the caller. This wart makes
2392 life simpler in print_z_candidates and for the translators. */
2394 static void
2396 {
2398 {
2408 else
2411 }
2416 else
2418 }
2420 static void
2422 {
2427 /* There may be duplicates in the set of candidates. We put off
2428 checking this condition as long as possible, since we have no way
2429 to eliminate duplicates from a set of functions in less than n^2
2430 time. Now we are about to emit an error message, so it is more
2431 permissible to go slowly. */
2433 {
2435 /* Skip builtin candidates and conversion functions. */
2440 {
2444 else
2446 }
2447 }
2455 {
2456 /* Indent successive candidates by the width of the translation
2457 of the above string. */
2464 do
2465 {
2468 }
2470 }
2471 }
2473 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2474 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2475 the result of the conversion function to convert it to the final
2476 desired type. Merge the two sequences into a single sequence,
2477 and return the merged sequence. */
2481 {
2486 /* Find the end of the second conversion sequence. */
2491 /* Replace the identity conversion with the user conversion
2492 sequence. */
2495 /* The entire sequence is a user-conversion sequence. */
2499 }
2501 /* Returns the best overload candidate to perform the requested
2502 conversion. This function is used for three the overloading situations
2503 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2504 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2505 per [dcl.init.ref], so we ignore temporary bindings. */
2509 {
2518 /* We represent conversion within a hierarchy using RVALUE_CONV and
2519 BASE_CONV, as specified by [over.best.ics]; these become plain
2520 constructor calls, as specified in [dcl.init]. */
2534 {
2535 tree t;
2541 /* We should never try to call the abstract or base constructor
2542 from here. */
2546 }
2548 {
2558 flags,
2559 DEDUCE_CALL);
2560 else
2564 flags);
2568 }
2574 {
2575 tree fns;
2579 /* If we are called to convert to a reference type, we are trying to
2580 find an lvalue binding, so don't even consider temporaries. If
2581 we don't find an lvalue binding, the caller will try again to
2582 look for a temporary binding. */
2587 {
2590 /* [over.match.funcs] For conversion functions, the function
2591 is considered to be a member of the class of the implicit
2592 object argument for the purpose of defining the type of
2593 the implicit object parameter.
2595 So we pass fromtype as CTYPE to add_*_candidate. */
2599 NULL_TREE,
2602 conversion_path,
2603 flags,
2604 DEDUCE_CONV);
2605 else
2607 args,
2609 conversion_path,
2610 flags);
2613 {
2614 conversion *ics
2626 }
2627 }
2628 }
2636 {
2638 {
2642 }
2649 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
2650 ambiguous conversion is no worse than another user-defined
2651 conversion. */
2654 }
2656 /* Build the user conversion sequence. */
2657 conv = build_conv
2664 /* Combine it with the second conversion sequence. */
2672 }
2674 tree
2676 {
2681 {
2686 }
2688 }
2690 /* Do any initial processing on the arguments to a function call. */
2692 static tree
2694 {
2695 tree t;
2697 {
2703 {
2706 }
2709 }
2711 }
2713 /* Perform overload resolution on FN, which is called with the ARGS.
2715 Return the candidate function selected by overload resolution, or
2716 NULL if the event that overload resolution failed. In the case
2717 that overload resolution fails, *CANDIDATES will be the set of
2718 candidates considered, and ANY_VIABLE_P will be set to true or
2719 false to indicate whether or not any of the candidates were
2720 viable.
2722 The ARGS should already have gone through RESOLVE_ARGS before this
2723 function is called. */
2727 tree args,
2730 {
2738 /* Check FN and ARGS. */
2746 {
2750 }
2752 /* Add the various candidate functions. */
2756 LOOKUP_NORMAL,
2757 candidates);
2765 }
2767 /* Return an expression for a call to FN (a namespace-scope function,
2768 or a static member function) with the ARGS. */
2770 tree
2772 {
2776 tree result;
2782 /* If this function was found without using argument dependent
2783 lookup, then we want to ignore any undeclared friend
2784 functions. */
2786 {
2791 {
2795 }
2796 }
2798 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2804 {
2812 else
2818 }
2819 else
2822 /* Free all the conversions we allocated. */
2826 }
2828 /* Build a call to a global operator new. FNNAME is the name of the
2829 operator (either "operator new" or "operator new[]") and ARGS are
2830 the arguments provided. *SIZE points to the total number of bytes
2831 required by the allocation, and is updated if that is changed here.
2832 *COOKIE_SIZE is non-NULL if a cookie should be used. If this
2833 function determines that no cookie should be used, after all,
2834 *COOKIE_SIZE is set to NULL_TREE. */
2836 tree
2838 {
2839 tree fns;
2849 /* Based on:
2851 [expr.new]
2853 If this lookup fails to find the name, or if the allocated type
2854 is not a class type, the allocation function's name is looked
2855 up in the global scope.
2857 we disregard block-scope declarations of "operator new". */
2860 /* Figure out what function is being called. */
2863 /* If no suitable function could be found, issue an error message
2864 and give up. */
2866 {
2870 else
2876 }
2878 /* If a cookie is required, add some extra space. Whether
2879 or not a cookie is required cannot be determined until
2880 after we know which function was called. */
2882 {
2885 {
2887 /* In G++ 3.2, the check was implemented incorrectly; it
2888 looked at the placement expression, rather than the
2889 type of the function. */
2892 ptr_type_node))
2894 }
2895 else
2896 {
2897 tree arg_types;
2900 /* Skip the size_t parameter. */
2902 /* Check the remaining parameters (if any). */
2906 ptr_type_node))
2908 }
2909 /* If we need a cookie, adjust the number of bytes allocated. */
2911 {
2912 /* Update the total size. */
2914 /* Update the argument list to reflect the adjusted size. */
2916 }
2917 else
2919 }
2921 /* Build the CALL_EXPR. */
2923 }
2925 static tree
2927 {
2936 {
2937 /* It's no good looking for an overloaded operator() on a
2938 pointer-to-member-function. */
2939 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
2941 }
2944 {
2948 }
2949 else
2957 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2961 {
2966 {
2974 else
2975 add_function_candidate
2978 }
2979 }
2984 {
2996 {
2999 add_template_conv_candidate
3003 else
3007 }
3008 }
3012 {
3016 }
3017 else
3018 {
3021 {
3025 }
3026 /* Since cand->fn will be a type, not a function, for a conversion
3027 function, we must be careful not to unconditionally look at
3028 DECL_NAME here. */
3032 else
3033 {
3037 }
3038 }
3040 /* Free all the conversions we allocated. */
3044 }
3046 static void
3049 {
3054 else
3058 {
3082 else
3086 }
3087 }
3089 /* Return the implicit conversion sequence that could be used to
3090 convert E1 to E2 in [expr.cond]. */
3094 {
3100 /* [expr.cond]
3102 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3103 implicitly converted (clause _conv_) to the type "reference to
3104 T2", subject to the constraint that in the conversion the
3105 reference must bind directly (_dcl.init.ref_) to E1. */
3107 {
3109 t1,
3110 e1,
3112 LOOKUP_NO_TEMP_BIND);
3115 }
3117 /* [expr.cond]
3119 If E1 and E2 have class type, and the underlying class types are
3120 the same or one is a base class of the other: E1 can be converted
3121 to match E2 if the class of T2 is the same type as, or a base
3122 class of, the class of T1, and the cv-qualification of T2 is the
3123 same cv-qualification as, or a greater cv-qualification than, the
3124 cv-qualification of T1. If the conversion is applied, E1 is
3125 changed to an rvalue of type T2 that still refers to the original
3126 source class object (or the appropriate subobject thereof). */
3129 {
3131 {
3136 else
3139 }
3140 else
3142 }
3143 else
3144 /* [expr.cond]
3146 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3147 converted to the type that expression E2 would have if E2 were
3148 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3150 LOOKUP_NORMAL);
3151 }
3153 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3154 arguments to the conditional expression. */
3156 tree
3158 {
3159 tree arg2_type;
3160 tree arg3_type;
3168 /* As a G++ extension, the second argument to the conditional can be
3169 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3170 c'.) If the second operand is omitted, make sure it is
3171 calculated only once. */
3173 {
3177 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3180 else
3182 }
3184 /* [expr.cond]
3186 The first expr ession is implicitly converted to bool (clause
3187 _conv_). */
3190 /* If something has already gone wrong, just pass that fact up the
3191 tree. */
3197 /* [expr.cond]
3199 If either the second or the third operand has type (possibly
3200 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3201 array-to-pointer (_conv.array_), and function-to-pointer
3202 (_conv.func_) standard conversions are performed on the second
3203 and third operands. */
3207 {
3208 /* Do the conversions. We don't these for `void' type arguments
3209 since it can't have any effect and since decay_conversion
3210 does not handle that case gracefully. */
3218 /* [expr.cond]
3220 One of the following shall hold:
3222 --The second or the third operand (but not both) is a
3223 throw-expression (_except.throw_); the result is of the
3224 type of the other and is an rvalue.
3226 --Both the second and the third operands have type void; the
3227 result is of type void and is an rvalue.
3229 We must avoid calling force_rvalue for expressions of type
3230 "void" because it will complain that their value is being
3231 used. */
3234 {
3239 }
3242 {
3247 }
3250 else
3251 {
3255 }
3259 }
3260 /* [expr.cond]
3262 Otherwise, if the second and third operand have different types,
3263 and either has (possibly cv-qualified) class type, an attempt is
3264 made to convert each of those operands to the type of the other. */
3267 {
3271 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3277 /* [expr.cond]
3279 If both can be converted, or one can be converted but the
3280 conversion is ambiguous, the program is ill-formed. If
3281 neither can be converted, the operands are left unchanged and
3282 further checking is performed as described below. If exactly
3283 one conversion is possible, that conversion is applied to the
3284 chosen operand and the converted operand is used in place of
3285 the original operand for the remainder of this section. */
3290 {
3293 }
3295 {
3299 /* Even if CONV2 is a valid conversion, the result of the
3300 conversion may be invalid. For example, if ARG3 has type
3301 "volatile X", and X does not have a copy constructor
3302 accepting a "volatile X&", then even if ARG2 can be
3303 converted to X, the conversion will fail. */
3306 }
3308 {
3314 }
3316 /* Free all the conversions we allocated. */
3322 /* If, after the conversion, both operands have class type,
3323 treat the cv-qualification of both operands as if it were the
3324 union of the cv-qualification of the operands.
3326 The standard is not clear about what to do in this
3327 circumstance. For example, if the first operand has type
3328 "const X" and the second operand has a user-defined
3329 conversion to "volatile X", what is the type of the second
3330 operand after this step? Making it be "const X" (matching
3331 the first operand) seems wrong, as that discards the
3332 qualification without actually performing a copy. Leaving it
3333 as "volatile X" seems wrong as that will result in the
3334 conditional expression failing altogether, even though,
3335 according to this step, the one operand could be converted to
3336 the type of the other. */
3344 }
3346 /* [expr.cond]
3348 If the second and third operands are lvalues and have the same
3349 type, the result is of that type and is an lvalue. */
3353 {
3356 }
3358 /* [expr.cond]
3360 Otherwise, the result is an rvalue. If the second and third
3361 operand do not have the same type, and either has (possibly
3362 cv-qualified) class type, overload resolution is used to
3363 determine the conversions (if any) to be applied to the operands
3364 (_over.match.oper_, _over.built_). */
3368 {
3373 /* Rearrange the arguments so that add_builtin_candidate only has
3374 to know about two args. In build_builtin_candidates, the
3375 arguments are unscrambled. */
3380 COND_EXPR,
3381 NOP_EXPR,
3383 args,
3384 LOOKUP_NORMAL);
3386 /* [expr.cond]
3388 If the overload resolution fails, the program is
3389 ill-formed. */
3392 {
3396 }
3399 {
3403 }
3405 /* [expr.cond]
3407 Otherwise, the conversions thus determined are applied, and
3408 the converted operands are used in place of the original
3409 operands for the remainder of this section. */
3416 }
3418 /* [expr.cond]
3420 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3421 and function-to-pointer (_conv.func_) standard conversions are
3422 performed on the second and third operands.
3424 We need to force the lvalue-to-rvalue conversion here for class types,
3425 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3426 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3427 regions. */
3440 /* [expr.cond]
3442 After those conversions, one of the following shall hold:
3444 --The second and third operands have the same type; the result is of
3445 that type. */
3448 /* [expr.cond]
3450 --The second and third operands have arithmetic or enumeration
3451 type; the usual arithmetic conversions are performed to bring
3452 them to a common type, and the result is of that type. */
3457 {
3458 /* In this case, there is always a common type. */
3460 arg3_type);
3475 }
3476 /* [expr.cond]
3478 --The second and third operands have pointer type, or one has
3479 pointer type and the other is a null pointer constant; pointer
3480 conversions (_conv.ptr_) and qualification conversions
3481 (_conv.qual_) are performed to bring them to their composite
3482 pointer type (_expr.rel_). The result is of the composite
3483 pointer type.
3485 --The second and third operands have pointer to member type, or
3486 one has pointer to member type and the other is a null pointer
3487 constant; pointer to member conversions (_conv.mem_) and
3488 qualification conversions (_conv.qual_) are performed to bring
3489 them to a common type, whose cv-qualification shall match the
3490 cv-qualification of either the second or the third operand.
3491 The result is of the common type. */
3499 {
3506 }
3509 {
3512 }
3514 valid_operands:
3517 /* We can't use result_type below, as fold might have returned a
3518 throw_expr. */
3520 /* Expand both sides into the same slot, hopefully the target of the
3521 ?: expression. We used to check for TARGET_EXPRs here, but now we
3522 sometimes wrap them in NOP_EXPRs so the test would fail. */
3526 /* If this expression is an rvalue, but might be mistaken for an
3527 lvalue, we must add a NON_LVALUE_EXPR. */
3532 }
3534 /* OPERAND is an operand to an expression. Perform necessary steps
3535 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
3536 returned. */
3538 static tree
3540 {
3542 {
3545 /* Make sure the template type is instantiated now. */
3547 }
3550 }
3552 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
3553 OVERLOAD) to the CANDIDATES, returning an updated list of
3554 CANDIDATES. The ARGS are the arguments provided to the call,
3555 without any implicit object parameter. The EXPLICIT_TARGS are
3556 explicit template arguments provided. TEMPLATE_ONLY is true if
3557 only template functions should be considered. CONVERSION_PATH,
3558 ACCESS_PATH, and FLAGS are as for add_function_candidate. */
3560 static void
3566 {
3567 tree ctype;
3568 tree non_static_args;
3571 /* Delay creating the implicit this parameter until it is needed. */
3575 {
3576 tree fn;
3577 tree fn_args;
3580 /* Figure out which set of arguments to use. */
3582 {
3583 /* If this function is a non-static member, prepend the implicit
3584 object parameter. */
3590 }
3591 else
3592 /* Otherwise, just use the list of arguments provided. */
3597 fn,
3598 ctype,
3599 explicit_targs,
3600 fn_args,
3601 NULL_TREE,
3602 access_path,
3603 conversion_path,
3604 flags,
3605 DEDUCE_CALL);
3608 fn,
3609 ctype,
3610 fn_args,
3611 access_path,
3612 conversion_path,
3613 flags);
3615 }
3616 }
3618 tree
3621 {
3639 {
3643 }
3644 else
3650 {
3655 /* Use build_op_new_call and build_op_delete_call instead. */
3663 }
3669 {
3676 }
3691 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3694 /* Add namespace-scope operators to the list of functions to
3695 consider. */
3699 /* Add class-member operators to the candidate set. */
3701 {
3702 tree fns;
3706 {
3709 }
3716 }
3718 /* Rearrange the arguments for ?: so that add_builtin_candidate only has
3719 to know about two args; a builtin candidate will always have a first
3720 parameter of type bool. We'll handle that in
3721 build_builtin_candidate. */
3723 {
3727 }
3728 else
3729 {
3733 }
3738 {
3741 /* For these, the built-in candidates set is empty
3742 [over.match.oper]/3. We don't want non-strict matches
3743 because exact matches are always possible with built-in
3744 operators. The built-in candidate set for COMPONENT_REF
3745 would be empty too, but since there are no such built-in
3746 operators, we accept non-strict matches for them. */
3753 }
3757 {
3759 {
3762 /* Look for an `operator++ (int)'. If they didn't have
3763 one, then we fall back to the old way of doing things. */
3767 fnname,
3771 else
3774 overloaded_p);
3777 /* The caller will deal with these. */
3787 {
3790 }
3793 }
3794 }
3795 else
3796 {
3799 {
3801 {
3804 }
3806 }
3808 {
3813 }
3814 else
3815 {
3816 /* Give any warnings we noticed during overload resolution. */
3818 {
3822 }
3824 /* Check for comparison of different enum types. */
3826 {
3837 {
3840 }
3844 }
3846 /* We need to strip any leading REF_BIND so that bitfields
3847 don't cause errors. This should not remove any important
3848 conversions, because builtins don't apply to class
3849 objects directly. */
3855 {
3860 }
3862 {
3867 }
3868 }
3869 }
3871 user_defined_result_ready:
3873 /* Free all the conversions we allocated. */
3879 builtin:
3881 {
3931 /* The caller will deal with these. */
3939 }
3941 }
3943 /* Build a call to operator delete. This has to be handled very specially,
3944 because the restrictions on what signatures match are different from all
3945 other call instances. For a normal delete, only a delete taking (void *)
3946 or (void *, size_t) is accepted. For a placement delete, only an exact
3947 match with the placement new is accepted.
3949 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
3950 ADDR is the pointer to be deleted.
3951 SIZE is the size of the memory block to be deleted.
3952 GLOBAL_P is true if the delete-expression should not consider
3953 class-specific delete operators.
3954 PLACEMENT is the corresponding placement new call, or NULL_TREE. */
3956 tree
3959 {
3974 /* In [class.free]
3976 If the result of the lookup is ambiguous or inaccessible, or if
3977 the lookup selects a placement deallocation function, the
3978 program is ill-formed.
3980 Therefore, we ask lookup_fnfields to complain about ambiguity. */
3981 {
3985 }
3986 else
3993 {
3994 tree alloc_fn;
3995 tree call_expr;
3997 /* Find the allocation function that is being called. */
3999 /* Extract the function. */
4002 /* Then the second parm type. */
4004 /* Also the second argument. */
4006 }
4007 else
4008 {
4009 /* First try it without the size argument. */
4012 }
4014 /* Strip const and volatile from addr. */
4017 /* We make two tries at finding a matching `operator delete'. On
4018 the first pass, we look for a one-operator (or placement)
4019 operator delete. If we're not doing placement delete, then on
4020 the second pass we look for a two-argument delete. */
4022 {
4023 /* Go through the `operator delete' functions looking for one
4024 with a matching type. */
4026 fn;
4028 {
4029 tree t;
4031 /* The first argument must be "void *". */
4036 /* On the first pass, check the rest of the arguments. */
4038 {
4041 {
4046 }
4049 }
4050 /* On the second pass, the second argument must be
4051 "size_t". */
4056 }
4058 /* If we found a match, we're done. */
4061 }
4063 /* If we have a matching function, call it. */
4065 {
4066 /* Make sure we have the actual function, and not an
4067 OVERLOAD. */
4070 /* If the FN is a member function, make sure that it is
4071 accessible. */
4077 else
4082 {
4083 /* The placement args might not be suitable for overload
4084 resolution at this point, so build the call directly. */
4087 }
4088 else
4090 }
4092 /* If we are doing placement delete we do nothing if we don't find a
4093 matching op delete. */
4100 }
4102 /* If the current scope isn't allowed to access DECL along
4103 BASETYPE_PATH, give an error. The most derived class in
4104 BASETYPE_PATH is the one used to qualify DECL. */
4106 bool
4108 {
4112 {
4117 else
4121 }
4124 }
4126 /* Check that a callable constructor to initialize a temporary of
4127 TYPE from an EXPR exists. */
4129 static void
4131 {
4133 complete_ctor_identifier,
4135 type,
4136 LOOKUP_NORMAL | LOOKUP_ONLYCONVERTING
4137 | LOOKUP_NO_CONVERSION
4139 }
4141 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
4142 bitwise or of LOOKUP_* values. If any errors are warnings are
4143 generated, set *DIAGNOSTIC_FN to "error" or "warning",
4144 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
4145 to NULL. */
4147 static tree
4150 {
4155 complete_ctor_identifier,
4162 else
4165 }
4168 /* Perform the conversions in CONVS on the expression EXPR. FN and
4169 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4170 indicates the `this' argument of a method. INNER is nonzero when
4171 being called to continue a conversion chain. It is negative when a
4172 reference binding will be applied, positive otherwise. If
4173 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
4174 conversions will be emitted if appropriate. If C_CAST_P is true,
4175 this conversion is coming from a C-style cast; in that case,
4176 conversions to inaccessible bases are permitted. */
4178 static tree
4182 {
4184 diagnostic_fn_t diagnostic_fn;
4190 {
4193 {
4195 {
4200 }
4207 }
4212 }
4215 {
4218 /* Issue warnings about peculiar, but valid, uses of NULL. */
4220 {
4224 else
4226 }
4228 /* Warn about assigning a floating-point type to an integer type. */
4231 {
4235 else
4237 }
4238 }
4241 {
4243 {
4246 tree args;
4249 {
4254 /* We should never try to call the abstract or base constructor
4255 from here. */
4259 }
4260 else
4264 /* If this is a constructor or a function returning an aggr type,
4265 we need to build up a TARGET_EXPR. */
4269 /* The result of the call is then used to direct-initialize the object
4270 that is the destination of the copy-initialization. [dcl.init]
4272 Note that this step is not reflected in the conversion sequence;
4273 it affects the semantics when we actually perform the
4274 conversion, but is not considered during overload resolution.
4276 If the target is a class, that means call a ctor. */
4279 {
4280 expr = (build_temp
4282 /* Core issue 84, now a DR, says that we don't
4283 allow UDCs for these args (which deliberately
4284 breaks copy-init of an auto_ptr<Base> from an
4285 auto_ptr<Derived>). */
4290 {
4292 diagnostic_fn
4295 else
4296 diagnostic_fn
4298 }
4300 }
4302 }
4306 /* Convert a constant to its underlying value, unless we are
4307 about to bind it to a reference, in which case we need to
4308 leave it as an lvalue. */
4315 /* Call build_user_type_conversion again for the error. */
4316 return build_user_type_conversion
4321 };
4326 c_cast_p);
4331 {
4335 /* Else fall through. */
4338 {
4339 /* We are going to bind a reference directly to a base-class
4340 subobject of EXPR. */
4343 /* Build an expression for `*((base*) &expr)'. */
4349 }
4351 /* Copy-initialization where the cv-unqualified version of the source
4352 type is the same class as, or a derived class of, the class of the
4353 destination [is treated as direct-initialization]. [dcl.init] */
4361 {
4364 /* If necessary, create a temporary. */
4366 {
4371 {
4372 /* If the reference is volatile or non-const, we
4373 cannot create a temporary. */
4380 else
4383 }
4384 /* If the source is a packed field, and we must use a copy
4385 constructor, then building the target expr will require
4386 binding the field to the reference parameter to the
4387 copy constructor, and we'll end up with an infinite
4388 loop. If we can use a bitwise copy, then we'll be
4389 OK. */
4393 {
4397 }
4399 }
4401 /* Take the address of the thing to which we will bind the
4402 reference. */
4407 /* Convert it to a pointer to the type referred to by the
4408 reference. This will adjust the pointer if a derived to
4409 base conversion is being performed. */
4411 expr);
4412 /* Convert the pointer to the desired reference type. */
4414 }
4420 /* Warn about deprecated conversion if appropriate. */
4432 c_cast_p);
4436 }
4440 else
4444 }
4446 /* Build a call to __builtin_trap. */
4448 static tree
4450 {
4456 }
4458 /* ARG is being passed to a varargs function. Perform any conversions
4459 required. Return the converted value. */
4461 tree
4463 {
4464 /* [expr.call]
4466 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
4467 standard conversions are performed. */
4469 /* [expr.call]
4471 If the argument has integral or enumeration type that is subject
4472 to the integral promotions (_conv.prom_), or a floating point
4473 type that is subject to the floating point promotion
4474 (_conv.fpprom_), the value of the argument is converted to the
4475 promoted type before the call. */
4487 {
4488 /* Undefined behavior [expr.call] 5.2.2/7. We used to just warn
4489 here and do a bitwise copy, but now cp_expr_size will abort if we
4490 try to do that.
4491 If the call appears in the context of a sizeof expression,
4492 there is no need to emit a warning, since the expression won't be
4493 evaluated. We keep the builtin_trap just as a safety check. */
4499 integer_zero_node);
4500 }
4503 }
4505 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
4507 tree
4509 {
4519 {
4520 /* Remove reference types so we don't ICE later on. */
4522 /* Undefined behavior [expr.call] 5.2.2/7. */
4530 }
4533 }
4535 /* TYPE has been given to va_arg. Apply the default conversions which
4536 would have happened when passed via ellipsis. Return the promoted
4537 type, or the passed type if there is no change. */
4539 tree
4541 {
4542 tree promote;
4544 /* Perform the array-to-pointer and function-to-pointer
4545 conversions. */
4553 }
4555 /* ARG is a default argument expression being passed to a parameter of
4556 the indicated TYPE, which is a parameter to FN. Do any required
4557 conversions. Return the converted value. */
4559 tree
4561 {
4562 /* If the ARG is an unparsed default argument expression, the
4563 conversion cannot be performed. */
4565 {
4570 }
4578 {
4582 }
4583 else
4584 {
4585 /* This could get clobbered by the following call. */
4592 }
4595 }
4597 /* Returns the type which will really be used for passing an argument of
4598 type TYPE. */
4600 tree
4602 {
4603 /* Pass classes with copy ctors by invisible reference. */
4605 {
4607 /* There are no other pointers to this temporary. */
4609 }
4618 }
4620 /* Actually perform the appropriate conversion. */
4622 tree
4624 {
4626 ;
4627 /* Pass classes with copy ctors by invisible reference. */
4637 {
4646 }
4648 }
4650 /* Returns true iff FN is a function with magic varargs, i.e. ones for
4651 which no conversions at all should be done. This is true for some
4652 builtins which don't act like normal functions. */
4654 static bool
4656 {
4659 {
4668 }
4671 }
4673 /* Subroutine of the various build_*_call functions. Overload resolution
4674 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
4675 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
4676 bitmask of various LOOKUP_* flags which apply to the call itself. */
4678 static tree
4680 {
4691 /* In a template, there is no need to perform all of the work that
4692 is normally done. We are only interested in the type of the call
4693 expression, i.e., the return type of the function. Any semantic
4694 errors will be deferred until the template is instantiated. */
4696 {
4697 tree expr;
4698 tree return_type;
4706 }
4708 /* Give any warnings we noticed during overload resolution. */
4710 {
4714 }
4717 {
4718 /* If FN is a template function, two cases must be considered.
4719 For example:
4721 struct A {
4722 protected:
4723 template <class T> void f();
4724 };
4725 template <class T> struct B {
4726 protected:
4727 void g();
4728 };
4729 struct C : A, B<int> {
4730 using A::f; // #1
4731 using B<int>::g; // #2
4732 };
4734 In case #1 where `A::f' is a member template, DECL_ACCESS is
4735 recorded in the primary template but not in its specialization.
4736 We check access of FN using its primary template.
4738 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
4739 because it is a member of class template B, DECL_ACCESS is
4740 recorded in the specialization `B<int>::g'. We cannot use its
4741 primary template because `B<T>::g' and `B<int>::g' may have
4742 different access. */
4747 else
4749 }
4755 /* The implicit parameters to a constructor are not considered by overload
4756 resolution, and must be of the proper type. */
4758 {
4762 /* We should never try to call the abstract constructor. */
4766 {
4767 converted_args = tree_cons
4771 }
4772 }
4773 /* Bypass access control for 'this' parameter. */
4775 {
4778 tree converted_arg;
4779 tree base_binfo;
4785 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
4786 X is called for an object that is not of type X, or of a type
4787 derived from X, the behavior is undefined.
4789 So we can assume that anything passed as 'this' is non-null, and
4790 optimize accordingly. */
4792 /* Convert to the base in which the function was declared. */
4798 /* Check that the base class is accessible. */
4804 /* If fn was found by a using declaration, the conversion path
4805 will be to the derived class, not the base declaring fn. We
4806 must convert from derived to base. */
4817 }
4821 {
4826 /* Don't make a copy here if build_call is going to. */
4831 val = convert_like_with_context
4836 }
4838 /* Default arguments */
4840 converted_args
4845 converted_args);
4847 /* Ellipsis */
4849 {
4853 else
4856 }
4863 /* Avoid actually calling copy constructors and copy assignment operators,
4864 if possible. */
4869 {
4870 tree targ;
4874 /* Pull out the real argument, disregarding const-correctness. */
4881 {
4886 }
4887 else
4892 else
4895 /* [class.copy]: the copy constructor is implicitly defined even if
4896 the implementation elided its use. */
4900 /* If we're creating a temp and we already have one, don't create a
4901 new one. If we're not creating a temp but we get one, use
4902 INIT_EXPR to collapse the temp into our target. Otherwise, if the
4903 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
4904 temp or an INIT_EXPR otherwise. */
4906 {
4911 }
4914 {
4915 tree to = stabilize_reference
4920 }
4921 }
4925 {
4926 tree to = stabilize_reference
4933 {
4936 }
4937 else
4938 {
4939 /* We must only copy the non-tail padding parts.
4940 Use __builtin_memcpy for the bitwise copy. */
4953 }
4956 }
4961 {
4974 else
4977 }
4980 else
4984 }
4986 /* Build and return a call to FN, using ARGS. This function performs
4987 no overload resolution, conversion, or other high-level
4988 operations. */
4990 tree
4992 {
4993 tree fndecl;
4997 /* If this call might throw an exception, note that fact. */
5004 /* Some built-in function calls will be evaluated at compile-time in
5005 fold (). */
5018 }
5022 /* Make an expression which yields the address of the Java interface
5023 method FN. This is achieved by generating a call to libjava's
5024 _Jv_LookupInterfaceMethodIdx(). */
5026 static tree
5028 {
5034 {
5039 endlink)));
5040 java_iface_lookup_fn
5044 }
5046 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
5047 This is the first entry in the vtable. */
5049 integer_zero_node);
5051 /* Get the java.lang.Class pointer for the interface being called. */
5056 {
5058 iface);
5060 }
5064 /* Determine the itable index of FN. */
5067 {
5072 i++;
5073 }
5081 java_iface_lookup_fn);
5083 }
5085 /* Returns the value to use for the in-charge parameter when making a
5086 call to a function with the indicated NAME.
5088 FIXME:Can't we find a neater way to do this mapping? */
5090 tree
5092 {
5103 /* This function should only be called with one of the names listed
5104 above. */
5107 }
5109 /* Build a call to a constructor, destructor, or an assignment
5110 operator for INSTANCE, an expression with class type. NAME
5111 indicates the special member function to call; ARGS are the
5112 arguments. BINFO indicates the base of INSTANCE that is to be
5113 passed as the `this' parameter to the member function called.
5115 FLAGS are the LOOKUP_* flags to use when processing the call.
5117 If NAME indicates a complete object constructor, INSTANCE may be
5118 NULL_TREE. In this case, the caller will call build_cplus_new to
5119 store the newly constructed object into a VAR_DECL. */
5121 tree
5124 {
5125 tree fns;
5126 /* The type of the subobject to be constructed or destroyed. */
5127 tree class_type;
5136 {
5137 /* Resolve the name. */
5142 }
5148 /* Handle the special case where INSTANCE is NULL_TREE. */
5150 {
5153 }
5154 else
5155 {
5161 /* Convert to the base class, if necessary. */
5164 {
5166 /* For constructors and destructors, either the base is
5167 non-virtual, or it is virtual but we are doing the
5168 conversion from a constructor or destructor for the
5169 complete object. In either case, we can convert
5170 statically. */
5172 else
5173 /* However, for assignment operators, we must convert
5174 dynamically if the base is virtual. */
5177 }
5178 }
5184 /* When making a call to a constructor or destructor for a subobject
5185 that uses virtual base classes, pass down a pointer to a VTT for
5186 the subobject. */
5190 {
5191 tree vtt;
5192 tree sub_vtt;
5194 /* If the current function is a complete object constructor
5195 or destructor, then we fetch the VTT directly.
5196 Otherwise, we look it up using the VTT we were given. */
5202 current_vtt_parm,
5203 vtt);
5209 }
5213 flags);
5214 }
5216 /* Return the NAME, as a C string. The NAME indicates a function that
5217 is a member of TYPE. *FREE_P is set to true if the caller must
5218 free the memory returned.
5220 Rather than go through all of this, we should simply set the names
5221 of constructors and destructors appropriately, and dispense with
5222 ctor_identifier, dtor_identifier, etc. */
5226 {
5229 /* Assume that we will not allocate memory. */
5231 /* Constructors and destructors are special. */
5233 {
5234 pretty_name
5236 /* For a destructor, add the '~'. */
5240 {
5242 /* Remember that we need to free the memory allocated. */
5244 }
5245 }
5247 {
5250 TFF_PLAIN_IDENTIFIER),
5251 NULL);
5252 /* Remember that we need to free the memory allocated. */
5254 }
5255 else
5259 }
5261 /* Build a call to "INSTANCE.FN (ARGS)". */
5263 tree
5266 {
5270 tree access_binfo;
5271 tree optype;
5273 tree name;
5274 tree user_args;
5275 tree call;
5276 tree fn;
5277 tree class_type;
5280 tree orig_instance;
5281 tree orig_fns;
5282 tree orig_args;
5293 {
5296 }
5302 /* Dismantle the baselink to collect all the information we need. */
5309 {
5313 }
5324 {
5327 }
5329 /* The USER_ARGS are the arguments we will display to users if an
5330 error occurs. The USER_ARGS should not include any
5331 compiler-generated arguments. The "this" pointer hasn't been
5332 added yet. However, we must remove the VTT pointer if this is a
5333 call to a base-class constructor or destructor. */
5336 {
5337 /* Callers should explicitly indicate whether they want to construct
5338 the complete object or just the part without virtual bases. */
5340 /* Similarly for destructors. */
5342 /* Remove the VTT pointer, if present. */
5346 }
5348 /* Process the argument list. */
5355 /* It's OK to call destructors on cv-qualified objects. Therefore,
5356 convert the INSTANCE_PTR to the unqualified type, if necessary. */
5358 {
5363 }
5368 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5372 {
5374 tree this_arglist;
5376 /* We can end up here for copy-init of same or base class. */
5383 else
5387 /* A member template. */
5389 class_type,
5390 explicit_targs,
5392 access_binfo,
5393 conversion_path,
5394 flags,
5395 DEDUCE_CALL);
5398 class_type,
5399 this_arglist,
5400 access_binfo,
5401 conversion_path,
5402 flags);
5403 }
5407 {
5410 else
5411 {
5421 }
5424 }
5425 else
5426 {
5429 {
5435 user_args);
5440 }
5441 else
5442 {
5448 /* This is not an error, it is runtime undefined
5449 behavior. */
5451 "abstract virtual %q#D called from constructor"
5457 {
5461 }
5462 else
5463 {
5470 /* In an expression of the form `a->f()' where `f' turns
5471 out to be a static member function, `a' is
5472 none-the-less evaluated. */
5481 /* An explicit call of the form "x->~X()" has type
5482 "void". However, on platforms where destructors
5483 return "this" (i.e., those where
5484 targetm.cxx.cdtor_returns_this is true), such calls
5485 will appear to have a return value of pointer type
5486 to the low-level call machinery. We do not want to
5487 change the low-level machinery, since we want to be
5488 able to optimize "delete f()" on such platforms as
5489 "operator delete(~X(f()))" (rather than generating
5490 "t = f(), ~X(t), operator delete (t)"). */
5492 }
5493 }
5494 }
5497 call = (build_min_non_dep
5502 /* Free all the conversions we allocated. */
5506 }
5508 /* Returns true iff standard conversion sequence ICS1 is a proper
5509 subsequence of ICS2. */
5511 static bool
5513 {
5514 /* We can assume that a conversion of the same code
5515 between the same types indicates a subsequence since we only get
5516 here if the types we are converting from are the same. */
5523 {
5531 /* At this point, ICS1 cannot be a proper subsequence of
5532 ICS2. We can get a USER_CONV when we are comparing the
5533 second standard conversion sequence of two user conversion
5534 sequences. */
5544 }
5545 }
5547 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
5548 be any _TYPE nodes. */
5550 bool
5552 {
5557 /* We only allow proper derivation here. The DERIVED_FROM_P macro
5558 considers every class derived from itself. */
5561 }
5563 /* We build the ICS for an implicit object parameter as a pointer
5564 conversion sequence. However, such a sequence should be compared
5565 as if it were a reference conversion sequence. If ICS is the
5566 implicit conversion sequence for an implicit object parameter,
5567 modify it accordingly. */
5569 static void
5571 {
5573 {
5574 /* [over.match.funcs]
5576 For non-static member functions, the type of the
5577 implicit object parameter is "reference to cv X"
5578 where X is the class of which the function is a
5579 member and cv is the cv-qualification on the member
5580 function declaration. */
5582 tree reference_type;
5584 /* The `this' parameter is a pointer to a class type. Make the
5585 implicit conversion talk about a reference to that same class
5586 type. */
5597 }
5598 }
5600 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
5601 and return the type to which the reference refers. Otherwise,
5602 leave *ICS unchanged and return NULL_TREE. */
5604 static tree
5606 {
5608 {
5615 }
5618 }
5620 /* Compare two implicit conversion sequences according to the rules set out in
5621 [over.ics.rank]. Return values:
5623 1: ics1 is better than ics2
5624 -1: ics2 is better than ics1
5625 0: ics1 and ics2 are indistinguishable */
5627 static int
5629 {
5630 tree from_type1;
5631 tree from_type2;
5632 tree to_type1;
5633 tree to_type2;
5640 /* REF_BINDING is nonzero if the result of the conversion sequence
5641 is a reference type. In that case TARGET_TYPE is the
5642 type referred to by the reference. */
5643 tree target_type1;
5644 tree target_type2;
5646 /* Handle implicit object parameters. */
5650 /* Handle reference parameters. */
5654 /* [over.ics.rank]
5656 When comparing the basic forms of implicit conversion sequences (as
5657 defined in _over.best.ics_)
5659 --a standard conversion sequence (_over.ics.scs_) is a better
5660 conversion sequence than a user-defined conversion sequence
5661 or an ellipsis conversion sequence, and
5663 --a user-defined conversion sequence (_over.ics.user_) is a
5664 better conversion sequence than an ellipsis conversion sequence
5665 (_over.ics.ellipsis_). */
5675 {
5676 /* XXX Isn't this an extension? */
5677 /* Both ICS are bad. We try to make a decision based on what
5678 would have happened if they'd been good. */
5686 /* We couldn't make up our minds; try to figure it out below. */
5687 }
5690 /* Both conversions are ellipsis conversions. */
5693 /* User-defined conversion sequence U1 is a better conversion sequence
5694 than another user-defined conversion sequence U2 if they contain the
5695 same user-defined conversion operator or constructor and if the sec-
5696 ond standard conversion sequence of U1 is better than the second
5697 standard conversion sequence of U2. */
5700 {
5714 /* We can just fall through here, after setting up
5715 FROM_TYPE1 and FROM_TYPE2. */
5718 }
5719 else
5720 {
5724 /* We're dealing with two standard conversion sequences.
5726 [over.ics.rank]
5728 Standard conversion sequence S1 is a better conversion
5729 sequence than standard conversion sequence S2 if
5731 --S1 is a proper subsequence of S2 (comparing the conversion
5732 sequences in the canonical form defined by _over.ics.scs_,
5733 excluding any Lvalue Transformation; the identity
5734 conversion sequence is considered to be a subsequence of
5735 any non-identity conversion sequence */
5746 }
5749 {
5754 }
5755 /* Otherwise, one sequence cannot be a subsequence of the other; they
5756 don't start with the same type. This can happen when comparing the
5757 second standard conversion sequence in two user-defined conversion
5758 sequences. */
5760 /* [over.ics.rank]
5762 Or, if not that,
5764 --the rank of S1 is better than the rank of S2 (by the rules
5765 defined below):
5767 Standard conversion sequences are ordered by their ranks: an Exact
5768 Match is a better conversion than a Promotion, which is a better
5769 conversion than a Conversion.
5771 Two conversion sequences with the same rank are indistinguishable
5772 unless one of the following rules applies:
5774 --A conversion that is not a conversion of a pointer, or pointer
5775 to member, to bool is better than another conversion that is such
5776 a conversion.
5778 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
5779 so that we do not have to check it explicitly. */
5792 {
5797 }
5798 /* The rules for pointers to members A::* are just like the rules
5799 for pointers A*, except opposite: if B is derived from A then
5800 A::* converts to B::*, not vice versa. For that reason, we
5801 switch the from_ and to_ variables here. */
5808 {
5813 }
5818 {
5819 /* This was one of the pointer or pointer-like conversions.
5821 [over.ics.rank]
5823 --If class B is derived directly or indirectly from class A,
5824 conversion of B* to A* is better than conversion of B* to
5825 void*, and conversion of A* to void* is better than
5826 conversion of B* to void*. */
5829 {
5831 deref_from_type2))
5834 deref_from_type1))
5836 }
5839 {
5841 {
5843 {
5845 deref_to_type1))
5847 }
5848 /* We know that DEREF_TO_TYPE1 is `void' here. */
5850 deref_to_type2))
5852 }
5853 }
5856 {
5857 /* [over.ics.rank]
5859 --If class B is derived directly or indirectly from class A
5860 and class C is derived directly or indirectly from B,
5862 --conversion of C* to B* is better than conversion of C* to
5863 A*,
5865 --conversion of B* to A* is better than conversion of C* to
5866 A* */
5868 {
5870 deref_to_type2))
5873 deref_to_type1))
5875 }
5877 {
5879 deref_from_type1))
5882 deref_from_type2))
5884 }
5885 }
5886 }
5889 {
5892 /* [over.ics.rank]
5894 --binding of an expression of type C to a reference of type
5895 B& is better than binding an expression of type C to a
5896 reference of type A&
5898 --conversion of C to B is better than conversion of C to A, */
5901 {
5906 }
5907 }
5910 {
5913 /* [over.ics.rank]
5915 --binding of an expression of type B to a reference of type
5916 A& is better than binding an expression of type C to a
5917 reference of type A&,
5919 --conversion of B to A is better than conversion of C to A */
5922 {
5927 }
5928 }
5930 /* [over.ics.rank]
5932 --S1 and S2 differ only in their qualification conversion and yield
5933 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
5934 qualification signature of type T1 is a proper subset of the cv-
5935 qualification signature of type T2 */
5941 /* [over.ics.rank]
5943 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
5944 types to which the references refer are the same type except for
5945 top-level cv-qualifiers, and the type to which the reference
5946 initialized by S2 refers is more cv-qualified than the type to
5947 which the reference initialized by S1 refers */
5953 /* Neither conversion sequence is better than the other. */
5955 }
5957 /* The source type for this standard conversion sequence. */
5959 static tree
5961 {
5963 {
5968 }
5970 }
5972 /* Note a warning about preferring WINNER to LOSER. We do this by storing
5973 a pointer to LOSER and re-running joust to produce the warning if WINNER
5974 is actually used. */
5976 static void
5978 {
5985 }
5987 /* Compare two candidates for overloading as described in
5988 [over.match.best]. Return values:
5990 1: cand1 is better than cand2
5991 -1: cand2 is better than cand1
5992 0: cand1 and cand2 are indistinguishable */
5994 static int
5996 {
6002 /* Candidates that involve bad conversions are always worse than those
6003 that don't. */
6009 /* If we have two pseudo-candidates for conversions to the same type,
6010 or two candidates for the same function, arbitrarily pick one. */
6015 /* a viable function F1
6016 is defined to be a better function than another viable function F2 if
6017 for all arguments i, ICSi(F1) is not a worse conversion sequence than
6018 ICSi(F2), and then */
6020 /* for some argument j, ICSj(F1) is a better conversion sequence than
6021 ICSj(F2) */
6023 /* For comparing static and non-static member functions, we ignore
6024 the implicit object parameter of the non-static function. The
6025 standard says to pretend that the static function has an object
6026 parm, but that won't work with operator overloading. */
6029 {
6037 else
6038 {
6041 }
6042 }
6045 {
6051 {
6064 {
6071 else
6076 {
6080 }
6081 else
6083 }
6086 {
6089 }
6091 }
6092 }
6094 /* warn about confusing overload resolution for user-defined conversions,
6095 either between a constructor and a conversion op, or between two
6096 conversion ops. */
6100 {
6106 else
6109 /* We don't want to complain about `X::operator T1 ()'
6110 beating `X::operator T2 () const', when T2 is a no less
6111 cv-qualified version of T1. */
6114 {
6119 {
6122 }
6125 }
6126 else
6132 {
6140 }
6141 else
6143 }
6148 /* or, if not that,
6149 F1 is a non-template function and F2 is a template function
6150 specialization. */
6157 /* or, if not that,
6158 F1 and F2 are template functions and the function template for F1 is
6159 more specialized than the template for F2 according to the partial
6160 ordering rules. */
6163 {
6164 winner = more_specialized_fn
6167 /* [temp.func.order]: The presence of unused ellipsis and default
6168 arguments has no effect on the partial ordering of function
6169 templates. add_function_candidate() will not have
6170 counted the "this" argument for constructors. */
6174 }
6176 /* or, if not that,
6177 the context is an initialization by user-defined conversion (see
6178 _dcl.init_ and _over.match.user_) and the standard conversion
6179 sequence from the return type of F1 to the destination type (i.e.,
6180 the type of the entity being initialized) is a better conversion
6181 sequence than the standard conversion sequence from the return type
6182 of F2 to the destination type. */
6185 {
6189 }
6191 /* Check whether we can discard a builtin candidate, either because we
6192 have two identical ones or matching builtin and non-builtin candidates.
6194 (Pedantically in the latter case the builtin which matched the user
6195 function should not be added to the overload set, but we spot it here.
6197 [over.match.oper]
6198 ... the builtin candidates include ...
6199 - do not have the same parameter type list as any non-template
6200 non-member candidate. */
6204 {
6210 {
6212 /* Two built-in candidates; arbitrarily pick one. */
6215 /* cand1 is built-in; prefer cand2. */
6217 else
6218 /* cand2 is built-in; prefer cand1. */
6220 }
6221 }
6223 /* If the two functions are the same (this can happen with declarations
6224 in multiple scopes and arg-dependent lookup), arbitrarily choose one. */
6229 tweak:
6231 /* Extension: If the worst conversion for one candidate is worse than the
6232 worst conversion for the other, take the first. */
6234 {
6239 {
6244 }
6250 {
6252 {
6254 ISO C++ says that these are ambiguous, even \
6255 though the worst conversion for the first is better than \
6259 }
6260 else
6263 }
6264 }
6268 }
6270 /* Given a list of candidates for overloading, find the best one, if any.
6271 This algorithm has a worst case of O(2n) (winner is last), and a best
6272 case of O(n/2) (totally ambiguous); much better than a sorting
6273 algorithm. */
6277 {
6282 /* Walk through the list once, comparing each current champ to the next
6283 candidate, knocking out a candidate or two with each comparison. */
6286 {
6290 else
6291 {
6293 {
6298 }
6299 else
6300 {
6303 }
6306 }
6307 }
6309 /* Make sure the champ is better than all the candidates it hasn't yet
6310 been compared to. */
6313 challenger != champ
6316 {
6320 }
6323 }
6325 /* Returns nonzero if things of type FROM can be converted to TO. */
6327 bool
6329 {
6331 }
6333 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
6335 bool
6337 {
6342 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6346 flags);
6349 /* Free all the conversions we allocated. */
6353 }
6355 /* Like can_convert_arg, but allows dubious conversions as well. */
6357 bool
6359 {
6363 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6365 /* Try to perform the conversion. */
6367 LOOKUP_NORMAL);
6368 /* Free all the conversions we allocated. */
6372 }
6374 /* Convert EXPR to TYPE. Return the converted expression.
6376 Note that we allow bad conversions here because by the time we get to
6377 this point we are committed to doing the conversion. If we end up
6378 doing a bad conversion, convert_like will complain. */
6380 tree
6382 {
6389 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6394 LOOKUP_NORMAL);
6396 {
6399 }
6401 {
6402 /* In a template, we are only concerned about determining the
6403 type of non-dependent expressions, so we do not have to
6404 perform the actual conversion. */
6407 }
6408 else
6411 /* Free all the conversions we allocated. */
6415 }
6417 /* Convert EXPR to TYPE (as a direct-initialization) if that is
6418 permitted. If the conversion is valid, the converted expression is
6419 returned. Otherwise, NULL_TREE is returned, except in the case
6420 that TYPE is a class type; in that case, an error is issued. If
6421 C_CAST_P is true, then this direction initialization is taking
6422 place as part of a static_cast being attempted as part of a C-style
6423 cast. */
6425 tree
6427 tree expr,
6429 {
6435 /* [dcl.init]
6437 If the destination type is a (possibly cv-qualified) class type:
6439 -- If the initialization is direct-initialization ...,
6440 constructors are considered. ... If no constructor applies, or
6441 the overload resolution is ambiguous, the initialization is
6442 ill-formed. */
6444 {
6449 }
6451 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6455 c_cast_p,
6456 LOOKUP_NORMAL);
6459 else
6462 c_cast_p);
6464 /* Free all the conversions we allocated. */
6468 }
6470 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
6471 is being bound to a temporary. Create and return a new VAR_DECL
6472 with the indicated TYPE; this variable will store the value to
6473 which the reference is bound. */
6475 tree
6477 {
6478 tree var;
6480 /* Create the variable. */
6483 /* Register the variable. */
6485 {
6486 /* Namespace-scope or local static; give it a mangled name. */
6487 tree name;
6494 }
6495 else
6496 /* Create a new cleanup level if necessary. */
6500 }
6502 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
6503 initializing a variable of that TYPE. If DECL is non-NULL, it is
6504 the VAR_DECL being initialized with the EXPR. (In that case, the
6505 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
6506 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
6507 return, if *CLEANUP is no longer NULL, it will be an expression
6508 that should be pushed as a cleanup after the returned expression
6509 is used to initialize DECL.
6511 Return the converted expression. */
6513 tree
6515 {
6522 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6526 LOOKUP_NORMAL);
6528 {
6534 else
6539 }
6541 /* If DECL is non-NULL, then this special rule applies:
6543 [class.temporary]
6545 The temporary to which the reference is bound or the temporary
6546 that is the complete object to which the reference is bound
6547 persists for the lifetime of the reference.
6549 The temporaries created during the evaluation of the expression
6550 initializing the reference, except the temporary to which the
6551 reference is bound, are destroyed at the end of the
6552 full-expression in which they are created.
6554 In that case, we store the converted expression into a new
6555 VAR_DECL in a new scope.
6557 However, we want to be careful not to create temporaries when
6558 they are not required. For example, given:
6560 struct B {};
6561 struct D : public B {};
6562 D f();
6563 const B& b = f();
6565 there is no need to copy the return value from "f"; we can just
6566 extend its lifetime. Similarly, given:
6568 struct S {};
6569 struct T { operator S(); };
6570 T t;
6571 const S& s = t;
6573 we can extend the lifetime of the return value of the conversion
6574 operator. */
6577 {
6578 tree var;
6579 tree base_conv_type;
6581 /* Skip over the REF_BIND. */
6583 /* If the next conversion is a BASE_CONV, skip that too -- but
6584 remember that the conversion was required. */
6586 {
6591 }
6592 else
6594 /* Perform the remainder of the conversion. */
6602 else
6603 {
6605 {
6606 tree init;
6607 tree type;
6609 /* Create the temporary variable. */
6613 /* If the rvalue is the result of a function call it will be
6614 a TARGET_EXPR. If it is some other construct (such as a
6615 member access expression where the underlying object is
6616 itself the result of a function call), turn it into a
6617 TARGET_EXPR here. It is important that EXPR be a
6618 TARGET_EXPR below since otherwise the INIT_EXPR will
6619 attempt to make a bitwise copy of EXPR to initialize
6620 VAR. */
6623 /* Create the INIT_EXPR that will initialize the temporary
6624 variable. */
6627 {
6631 /* We must be careful to destroy the temporary only
6632 after its initialization has taken place. If the
6633 initialization throws an exception, then the
6634 destructor should not be run. We cannot simply
6635 transform INIT into something like:
6637 (INIT, ({ CLEANUP_STMT; }))
6639 because emit_local_var always treats the
6640 initializer as a full-expression. Thus, the
6641 destructor would run too early; it would run at the
6642 end of initializing the reference variable, rather
6643 than at the end of the block enclosing the
6644 reference variable.
6646 The solution is to pass back a cleanup expression
6647 which the caller is responsible for attaching to
6648 the statement tree. */
6649 }
6650 else
6651 {
6655 static_aggregates);
6656 }
6657 /* Use its address to initialize the reference variable. */
6665 }
6666 else
6667 /* Take the address of EXPR. */
6669 /* If a BASE_CONV was required, perform it now. */
6671 expr = (perform_implicit_conversion
6674 }
6675 }
6676 else
6677 /* Perform the conversion. */
6680 /* Free all the conversions we allocated. */
6684 }