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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
202 (a BIT_NOT_EXPR) matches BASETYPE. The operand of NAME can take many
203 forms... */
205 bool
207 {
210 /* Just accept something we've already complained about. */
219 {
224 else
226 }
227 else
228 {
229 /* In the case of:
231 template <class T> struct S { ~S(); };
232 int i;
233 i.~S();
235 NAME will be a class template. */
238 }
243 }
245 /* We want the address of a function or method. We avoid creating a
246 pointer-to-member function. */
248 tree
250 {
253 /* We have to do these by hand to avoid real pointer to member
254 functions. */
256 {
258 {
262 }
264 }
265 else
269 }
271 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
272 POINTER_TYPE to those. Note, pointer to member function types
273 (TYPE_PTRMEMFUNC_P) must be handled by our callers. */
275 tree
277 {
280 tree tmp;
281 tree decl;
282 tree result_type;
283 tree fntype;
288 {
291 }
299 else
302 /* We check both the decl and the type; a function may be known not to
303 throw without being declared throw(). */
318 {
319 /* We invoke build_call directly for several library functions.
320 These may have been declared normally if we're building libgcc,
321 so we can't just check DECL_ARTIFICIAL. */
326 }
328 /* Don't pass empty class objects by value. This is useful
329 for tags in STL, which are used to control overload resolution.
330 We don't need to handle other cases of copying empty classes. */
335 {
339 }
346 }
348 /* Build something of the form ptr->method (args)
349 or object.method (args). This can also build
350 calls to constructors, and find friends.
352 Member functions always take their class variable
353 as a pointer.
355 INSTANCE is a class instance.
357 NAME is the name of the method desired, usually an IDENTIFIER_NODE.
359 PARMS help to figure out what that NAME really refers to.
361 BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
362 down to the real instance type to use for access checking. We need this
363 information to get protected accesses correct.
365 FLAGS is the logical disjunction of zero or more LOOKUP_
366 flags. See cp-tree.h for more info.
368 If this is all OK, calls build_function_call with the resolved
369 member function.
371 This function must also handle being called to perform
372 initialization, promotion/coercion of arguments, and
373 instantiation of default parameters.
375 Note that NAME may refer to an instance variable name. If
376 `operator()()' is defined for the type of that field, then we return
377 that result. */
379 /* New overloading code. */
387 };
390 /* The FUNCTION_DECL that will be called if this candidate is
391 selected by overload resolution. */
392 tree fn;
393 /* The arguments to use when calling this function. */
394 tree args;
395 /* The implicit conversion sequences for each of the arguments to
396 FN. */
398 /* The number of implicit conversion sequences. */
400 /* If FN is a user-defined conversion, the standard conversion
401 sequence from the type returned by FN to the desired destination
402 type. */
405 /* If FN is a member function, the binfo indicating the path used to
406 qualify the name of FN at the call site. This path is used to
407 determine whether or not FN is accessible if it is selected by
408 overload resolution. The DECL_CONTEXT of FN will always be a
409 (possibly improper) base of this binfo. */
410 tree access_path;
411 /* If FN is a non-static member function, the binfo indicating the
412 subobject to which the `this' pointer should be converted if FN
413 is selected by overload resolution. The type pointed to the by
414 the `this' pointer must correspond to the most derived class
415 indicated by the CONVERSION_PATH. */
416 tree conversion_path;
417 tree template_decl;
420 };
422 /* Returns true iff T is a null pointer constant in the sense of
423 [conv.ptr]. */
425 bool
427 {
428 /* [conv.ptr]
430 A null pointer constant is an integral constant expression
431 (_expr.const_) rvalue of integer type that evaluates to zero. */
437 }
439 /* Returns nonzero if PARMLIST consists of only default parms and/or
440 ellipsis. */
442 bool
444 {
450 }
452 /* Allocate N bytes of memory from the conversion obstack. The memory
453 is zeroed before being returned. */
457 {
460 {
463 }
467 }
469 /* Dynamically allocate a conversion. */
473 {
478 }
480 #ifdef ENABLE_CHECKING
482 /* Make sure that all memory on the conversion obstack has been
483 freed. */
485 void
487 {
491 }
495 /* Dynamically allocate an array of N conversions. */
499 {
501 }
505 {
509 /* We can't use buildl1 here because CODE could be USER_CONV, which
510 takes two arguments. In that case, the caller is responsible for
511 filling in the second argument. */
517 {
533 }
539 }
541 /* Build a representation of the identity conversion from EXPR to
542 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
546 {
554 }
556 /* Converting from EXPR to TYPE was ambiguous in the sense that there
557 were multiple user-defined conversions to accomplish the job.
558 Build a conversion that indicates that ambiguity. */
562 {
570 }
572 tree
574 {
578 }
580 /* Returns the standard conversion path (see [conv]) from type FROM to type
581 TO, if any. For proper handling of null pointer constants, you must
582 also pass the expression EXPR to convert from. If C_CAST_P is true,
583 this conversion is coming from a C-style cast. */
588 {
595 {
598 }
604 {
609 }
616 {
620 }
622 {
626 }
630 /* Allow conversion between `__complex__' data types. */
632 {
633 /* The standard conversion sequence to convert FROM to TO is
634 the standard conversion sequence to perform componentwise
635 conversion. */
640 {
643 }
644 else
648 }
658 {
659 /* For backwards brain damage compatibility, allow interconversion of
660 pointers and integers with a pedwarn. */
663 }
665 {
666 /* For backwards brain damage compatibility, allow interconversion of
667 enums and integers with a pedwarn. */
670 }
673 {
674 tree to_pointee;
675 tree from_pointee;
680 ;
684 {
685 from = build_pointer_type
689 }
691 {
696 && (same_type_ignoring_top_level_qualifiers_p
699 {
703 }
706 }
709 /* [conv.ptr]
711 An rvalue of type "pointer to cv D," where D is a
712 class type, can be converted to an rvalue of type
713 "pointer to cv B," where B is a base class (clause
714 _class.derived_) of D. If B is an inaccessible
715 (clause _class.access_) or ambiguous
716 (_class.member.lookup_) base class of D, a program
717 that necessitates this conversion is ill-formed.
718 Therefore, we use DERIVED_FROM_P, and do not check
719 access or uniqueness. */
721 {
722 from =
728 }
731 {
734 }
735 else
736 {
739 }
744 /* In a C-style cast, we ignore CV-qualification because we
745 are allowed to perform a static_cast followed by a
746 const_cast. */
751 /* converting from string constant to char *. */
754 {
757 }
758 else
762 }
764 {
784 }
786 {
787 /* [conv.bool]
789 An rvalue of arithmetic, enumeration, pointer, or pointer to
790 member type can be converted to an rvalue of type bool. */
795 {
803 }
806 }
807 /* We don't check for ENUMERAL_TYPE here because there are no standard
808 conversions to enum type. */
811 {
816 /* Give this a better rank if it's a promotion. */
820 }
827 {
831 /* The derived-to-base conversion indicates the initialization
832 of a parameter with base type from an object of a derived
833 type. A temporary object is created to hold the result of
834 the conversion. */
836 }
837 else
841 }
843 /* Returns nonzero if T1 is reference-related to T2. */
845 static bool
847 {
851 /* [dcl.init.ref]
853 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
854 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
855 of T2. */
859 }
861 /* Returns nonzero if T1 is reference-compatible with T2. */
863 static bool
865 {
866 /* [dcl.init.ref]
868 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
869 reference-related to T2 and cv1 is the same cv-qualification as,
870 or greater cv-qualification than, cv2. */
873 }
875 /* Determine whether or not the EXPR (of class type S) can be
876 converted to T as in [over.match.ref]. */
880 {
881 tree conversions;
882 tree arglist;
884 tree reference_type;
893 /* [over.match.ref]
895 Assuming that "cv1 T" is the underlying type of the reference
896 being initialized, and "cv S" is the type of the initializer
897 expression, with S a class type, the candidate functions are
898 selected as follows:
900 --The conversion functions of S and its base classes are
901 considered. Those that are not hidden within S and yield type
902 "reference to cv2 T2", where "cv1 T" is reference-compatible
903 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
905 The argument list has one argument, which is the initializer
906 expression. */
910 /* Conceptually, we should take the address of EXPR and put it in
911 the argument list. Unfortunately, however, that can result in
912 error messages, which we should not issue now because we are just
913 trying to find a conversion operator. Therefore, we use NULL,
914 cast to the appropriate type. */
921 {
925 {
931 /* If this is a template function, try to get an exact
932 match. */
934 {
937 NULL_TREE,
938 arglist,
939 reference_type,
942 LOOKUP_NORMAL,
943 DEDUCE_CONV);
946 {
947 /* Now, see if the conversion function really returns
948 an lvalue of the appropriate type. From the
949 point of view of unification, simply returning an
950 rvalue of the right type is good enough. */
955 {
958 }
959 }
960 }
966 LOOKUP_NORMAL);
969 {
971 /* Build a standard conversion sequence indicating the
972 binding from the reference type returned by the
973 function to the desired REFERENCE_TYPE. */
974 identity_conv
977 NULL_TREE);
978 cand->second_conv
979 = (direct_reference_binding
982 }
983 }
985 }
988 /* If none of the conversion functions worked out, let our caller
989 know. */
997 /* Now that we know that this is the function we're going to use fix
998 the dummy first argument. */
1003 /* Build a user-defined conversion sequence representing the
1004 conversion. */
1010 /* Merge it with the standard conversion sequence from the
1011 conversion function's return type to the desired type. */
1018 }
1020 /* A reference of the indicated TYPE is being bound directly to the
1021 expression represented by the implicit conversion sequence CONV.
1022 Return a conversion sequence for this binding. */
1026 {
1027 tree t;
1034 /* [over.ics.rank]
1036 When a parameter of reference type binds directly
1037 (_dcl.init.ref_) to an argument expression, the implicit
1038 conversion sequence is the identity conversion, unless the
1039 argument expression has a type that is a derived class of the
1040 parameter type, in which case the implicit conversion sequence is
1041 a derived-to-base Conversion.
1043 If the parameter binds directly to the result of applying a
1044 conversion function to the argument expression, the implicit
1045 conversion sequence is a user-defined conversion sequence
1046 (_over.ics.user_), with the second standard conversion sequence
1047 either an identity conversion or, if the conversion function
1048 returns an entity of a type that is a derived class of the
1049 parameter type, a derived-to-base conversion. */
1051 {
1052 /* Represent the derived-to-base conversion. */
1054 /* We will actually be binding to the base-class subobject in
1055 the derived class, so we mark this conversion appropriately.
1056 That way, convert_like knows not to generate a temporary. */
1058 }
1060 }
1062 /* Returns the conversion path from type FROM to reference type TO for
1063 purposes of reference binding. For lvalue binding, either pass a
1064 reference type to FROM or an lvalue expression to EXPR. If the
1065 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1066 the conversion returned. */
1070 {
1079 {
1084 }
1087 {
1088 /* Anything with reference type is an lvalue. */
1091 }
1095 /* Figure out whether or not the types are reference-related and
1096 reference compatible. We have do do this after stripping
1097 references from FROM. */
1102 {
1103 /* [dcl.init.ref]
1105 If the initializer expression
1107 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1108 is reference-compatible with "cv2 T2,"
1110 the reference is bound directly to the initializer expression
1111 lvalue. */
1116 /* For the purposes of overload resolution, we ignore the fact
1117 this expression is a bitfield or packed field. (In particular,
1118 [over.ics.ref] says specifically that a function with a
1119 non-const reference parameter is viable even if the
1120 argument is a bitfield.)
1122 However, when we actually call the function we must create
1123 a temporary to which to bind the reference. If the
1124 reference is volatile, or isn't const, then we cannot make
1125 a temporary, so we just issue an error when the conversion
1126 actually occurs. */
1130 }
1132 {
1133 /* [dcl.init.ref]
1135 If the initializer expression
1137 -- has a class type (i.e., T2 is a class type) can be
1138 implicitly converted to an lvalue of type "cv3 T3," where
1139 "cv1 T1" is reference-compatible with "cv3 T3". (this
1140 conversion is selected by enumerating the applicable
1141 conversion functions (_over.match.ref_) and choosing the
1142 best one through overload resolution. (_over.match_).
1144 the reference is bound to the lvalue result of the conversion
1145 in the second case. */
1149 }
1151 /* From this point on, we conceptually need temporaries, even if we
1152 elide them. Only the cases above are "direct bindings". */
1156 /* [over.ics.rank]
1158 When a parameter of reference type is not bound directly to an
1159 argument expression, the conversion sequence is the one required
1160 to convert the argument expression to the underlying type of the
1161 reference according to _over.best.ics_. Conceptually, this
1162 conversion sequence corresponds to copy-initializing a temporary
1163 of the underlying type with the argument expression. Any
1164 difference in top-level cv-qualification is subsumed by the
1165 initialization itself and does not constitute a conversion. */
1167 /* [dcl.init.ref]
1169 Otherwise, the reference shall be to a non-volatile const type. */
1173 /* [dcl.init.ref]
1175 If the initializer expression is an rvalue, with T2 a class type,
1176 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1177 is bound in one of the following ways:
1179 -- The reference is bound to the object represented by the rvalue
1180 or to a sub-object within that object.
1182 -- ...
1184 We use the first alternative. The implicit conversion sequence
1185 is supposed to be same as we would obtain by generating a
1186 temporary. Fortunately, if the types are reference compatible,
1187 then this is either an identity conversion or the derived-to-base
1188 conversion, just as for direct binding. */
1190 {
1196 }
1198 /* [dcl.init.ref]
1200 Otherwise, a temporary of type "cv1 T1" is created and
1201 initialized from the initializer expression using the rules for a
1202 non-reference copy initialization. If T1 is reference-related to
1203 T2, cv1 must be the same cv-qualification as, or greater
1204 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1209 flags);
1214 /* This reference binding, unlike those above, requires the
1215 creation of a temporary. */
1219 }
1221 /* Returns the implicit conversion sequence (see [over.ics]) from type
1222 FROM to type TO. The optional expression EXPR may affect the
1223 conversion. FLAGS are the usual overloading flags. Only
1224 LOOKUP_NO_CONVERSION is significant. If C_CAST_P is true, this
1225 conversion is coming from a C-style cast. */
1230 {
1239 else
1249 {
1252 cand = build_user_type_conversion_1
1257 /* We used to try to bind a reference to a temporary here, but that
1258 is now handled by the recursive call to this function at the end
1259 of reference_binding. */
1261 }
1264 }
1266 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1267 functions. */
1275 {
1290 }
1292 /* Create an overload candidate for the function or method FN called with
1293 the argument list ARGLIST and add it to CANDIDATES. FLAGS is passed on
1294 to implicit_conversion.
1296 CTYPE, if non-NULL, is the type we want to pretend this function
1297 comes from for purposes of overload resolution. */
1304 {
1309 tree orig_arglist;
1312 /* At this point we should not see any functions which haven't been
1313 explicitly declared, except for friend functions which will have
1314 been found using argument dependent lookup. */
1317 /* The `this', `in_chrg' and VTT arguments to constructors are not
1318 considered in overload resolution. */
1320 {
1324 }
1325 else
1331 /* 13.3.2 - Viable functions [over.match.viable]
1332 First, to be a viable function, a candidate function shall have enough
1333 parameters to agree in number with the arguments in the list.
1335 We need to check this first; otherwise, checking the ICSes might cause
1336 us to produce an ill-formed template instantiation. */
1340 {
1344 }
1349 /* Make sure there are default args for the rest of the parms. */
1356 /* Second, for F to be a viable function, there shall exist for each
1357 argument an implicit conversion sequence that converts that argument
1358 to the corresponding parameter of F. */
1364 {
1377 {
1380 /* The type of the implicit object parameter ('this') for
1381 overload resolution is not always the same as for the
1382 function itself; conversion functions are considered to
1383 be members of the class being converted, and functions
1384 introduced by a using-declaration are considered to be
1385 members of the class that uses them.
1387 Since build_over_call ignores the ICS for the `this'
1388 parameter, we can just change the parm type. */
1390 {
1391 parmtype
1395 }
1399 }
1400 else
1401 {
1404 }
1411 {
1414 }
1422 }
1424 out:
1427 }
1429 /* Create an overload candidate for the conversion function FN which will
1430 be invoked for expression OBJ, producing a pointer-to-function which
1431 will in turn be called with the argument list ARGLIST, and add it to
1432 CANDIDATES. FLAGS is passed on to implicit_conversion.
1434 Actually, we don't really care about FN; we care about the type it
1435 converts to. There may be multiple conversion functions that will
1436 convert to that type, and we rely on build_user_type_conversion_1 to
1437 choose the best one; so when we create our candidate, we record the type
1438 instead of the function. */
1443 {
1460 /* Don't bother looking up the same type twice. */
1465 {
1472 flags);
1478 else
1479 {
1482 }
1497 }
1507 }
1509 static void
1513 {
1527 {
1534 {
1536 /* We need something for printing the candidate. */
1538 }
1542 }
1544 /* For COND_EXPR we rearranged the arguments; undo that now. */
1546 {
1553 else
1555 }
1561 viable);
1562 }
1564 static bool
1566 {
1568 }
1570 /* Returns nonzero if TYPE is a promoted arithmetic type. */
1572 static bool
1574 {
1575 /* [over.built]
1577 In this section, the term promoted integral type is used to refer
1578 to those integral types which are preserved by integral promotion
1579 (including e.g. int and long but excluding e.g. char).
1580 Similarly, the term promoted arithmetic type refers to promoted
1581 integral types plus floating types. */
1585 }
1587 /* Create any builtin operator overload candidates for the operator in
1588 question given the converted operand types TYPE1 and TYPE2. The other
1589 args are passed through from add_builtin_candidates to
1590 build_builtin_candidate.
1592 TYPE1 and TYPE2 may not be permissible, and we must filter them.
1593 If CODE is requires candidates operands of the same type of the kind
1594 of which TYPE1 and TYPE2 are, we add both candidates
1595 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
1597 static void
1601 {
1603 {
1611 }
1614 {
1616 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
1617 and VQ is either volatile or empty, there exist candidate operator
1618 functions of the form
1619 VQ T& operator++(VQ T&);
1620 T operator++(VQ T&, int);
1621 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
1622 type other than bool, and VQ is either volatile or empty, there exist
1623 candidate operator functions of the form
1624 VQ T& operator--(VQ T&);
1625 T operator--(VQ T&, int);
1626 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
1627 complete object type, and VQ is either volatile or empty, there exist
1628 candidate operator functions of the form
1629 T*VQ& operator++(T*VQ&);
1630 T*VQ& operator--(T*VQ&);
1631 T* operator++(T*VQ&, int);
1632 T* operator--(T*VQ&, int); */
1641 {
1644 }
1647 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
1648 exist candidate operator functions of the form
1650 T& operator*(T*);
1652 8 For every function type T, there exist candidate operator functions of
1653 the form
1654 T& operator*(T*); */
1663 /* 9 For every type T, there exist candidate operator functions of the form
1664 T* operator+(T*);
1666 10For every promoted arithmetic type T, there exist candidate operator
1667 functions of the form
1668 T operator+(T);
1669 T operator-(T); */
1679 /* 11For every promoted integral type T, there exist candidate operator
1680 functions of the form
1681 T operator~(T); */
1688 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
1689 is the same type as C2 or is a derived class of C2, T is a complete
1690 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
1691 there exist candidate operator functions of the form
1692 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
1693 where CV12 is the union of CV1 and CV2. */
1698 {
1706 }
1709 /* 13For every pair of promoted arithmetic types L and R, there exist can-
1710 didate operator functions of the form
1711 LR operator*(L, R);
1712 LR operator/(L, R);
1713 LR operator+(L, R);
1714 LR operator-(L, R);
1715 bool operator<(L, R);
1716 bool operator>(L, R);
1717 bool operator<=(L, R);
1718 bool operator>=(L, R);
1719 bool operator==(L, R);
1720 bool operator!=(L, R);
1721 where LR is the result of the usual arithmetic conversions between
1722 types L and R.
1724 14For every pair of types T and I, where T is a cv-qualified or cv-
1725 unqualified complete object type and I is a promoted integral type,
1726 there exist candidate operator functions of the form
1727 T* operator+(T*, I);
1728 T& operator[](T*, I);
1729 T* operator-(T*, I);
1730 T* operator+(I, T*);
1731 T& operator[](I, T*);
1733 15For every T, where T is a pointer to complete object type, there exist
1734 candidate operator functions of the form112)
1735 ptrdiff_t operator-(T, T);
1737 16For every pointer or enumeration type T, there exist candidate operator
1738 functions of the form
1739 bool operator<(T, T);
1740 bool operator>(T, T);
1741 bool operator<=(T, T);
1742 bool operator>=(T, T);
1743 bool operator==(T, T);
1744 bool operator!=(T, T);
1746 17For every pointer to member type T, there exist candidate operator
1747 functions of the form
1748 bool operator==(T, T);
1749 bool operator!=(T, T); */
1755 {
1758 }
1771 {
1774 }
1776 {
1779 }
1780 /* Fall through. */
1794 {
1797 }
1799 {
1802 }
1810 {
1813 }
1815 {
1818 }
1821 /* 18For every pair of promoted integral types L and R, there exist candi-
1822 date operator functions of the form
1823 LR operator%(L, R);
1824 LR operator&(L, R);
1825 LR operator^(L, R);
1826 LR operator|(L, R);
1827 L operator<<(L, R);
1828 L operator>>(L, R);
1829 where LR is the result of the usual arithmetic conversions between
1830 types L and R. */
1842 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
1843 type, VQ is either volatile or empty, and R is a promoted arithmetic
1844 type, there exist candidate operator functions of the form
1845 VQ L& operator=(VQ L&, R);
1846 VQ L& operator*=(VQ L&, R);
1847 VQ L& operator/=(VQ L&, R);
1848 VQ L& operator+=(VQ L&, R);
1849 VQ L& operator-=(VQ L&, R);
1851 20For every pair T, VQ), where T is any type and VQ is either volatile
1852 or empty, there exist candidate operator functions of the form
1853 T*VQ& operator=(T*VQ&, T*);
1855 21For every pair T, VQ), where T is a pointer to member type and VQ is
1856 either volatile or empty, there exist candidate operator functions of
1857 the form
1858 VQ T& operator=(VQ T&, T);
1860 22For every triple T, VQ, I), where T is a cv-qualified or cv-
1861 unqualified complete object type, VQ is either volatile or empty, and
1862 I is a promoted integral type, there exist candidate operator func-
1863 tions of the form
1864 T*VQ& operator+=(T*VQ&, I);
1865 T*VQ& operator-=(T*VQ&, I);
1867 23For every triple L, VQ, R), where L is an integral or enumeration
1868 type, VQ is either volatile or empty, and R is a promoted integral
1869 type, there exist candidate operator functions of the form
1871 VQ L& operator%=(VQ L&, R);
1872 VQ L& operator<<=(VQ L&, R);
1873 VQ L& operator>>=(VQ L&, R);
1874 VQ L& operator&=(VQ L&, R);
1875 VQ L& operator^=(VQ L&, R);
1876 VQ L& operator|=(VQ L&, R); */
1880 {
1884 {
1887 }
1913 {
1916 }
1921 }
1926 /* [over.built]
1928 For every pair of promoted arithmetic types L and R, there
1929 exist candidate operator functions of the form
1931 LR operator?(bool, L, R);
1933 where LR is the result of the usual arithmetic conversions
1934 between types L and R.
1936 For every type T, where T is a pointer or pointer-to-member
1937 type, there exist candidate operator functions of the form T
1938 operator?(bool, T, T); */
1942 /* That's OK. */
1945 /* Otherwise, the types should be pointers. */
1950 /* We don't check that the two types are the same; the logic
1951 below will actually create two candidates; one in which both
1952 parameter types are TYPE1, and one in which both parameter
1953 types are TYPE2. */
1958 }
1960 /* If we're dealing with two pointer types or two enumeral types,
1961 we need candidates for both of them. */
1970 {
1971 build_builtin_candidate
1973 build_builtin_candidate
1976 }
1978 build_builtin_candidate
1980 }
1982 tree
1984 {
1990 }
1992 /* There are three conditions of builtin candidates:
1994 1) bool-taking candidates. These are the same regardless of the input.
1995 2) pointer-pair taking candidates. These are generated for each type
1996 one of the input types converts to.
1997 3) arithmetic candidates. According to the standard, we should generate
1998 all of these, but I'm trying not to...
2000 Here we generate a superset of the possible candidates for this particular
2001 case. That is a subset of the full set the standard defines, plus some
2002 other cases which the standard disallows. add_builtin_candidate will
2003 filter out the invalid set. */
2005 static void
2009 {
2013 /* TYPES[i] is the set of possible builtin-operator parameter types
2014 we will consider for the Ith argument. These are represented as
2015 a TREE_LIST; the TREE_VALUE of each node is the potential
2016 parameter type. */
2020 {
2023 else
2025 }
2028 {
2029 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2030 and VQ is either volatile or empty, there exist candidate operator
2031 functions of the form
2032 VQ T& operator++(VQ T&); */
2042 /* 24There also exist candidate operator functions of the form
2043 bool operator!(bool);
2044 bool operator&&(bool, bool);
2045 bool operator||(bool, bool); */
2048 build_builtin_candidate
2055 build_builtin_candidate
2073 /* Fall through. */
2077 }
2082 {
2084 ;
2086 {
2087 tree convs;
2095 {
2102 }
2108 {
2121 {
2127 }
2131 }
2132 }
2133 else
2134 {
2140 {
2146 }
2148 }
2149 }
2151 /* Run through the possible parameter types of both arguments,
2152 creating candidates with those parameter types. */
2154 {
2157 add_builtin_candidate
2160 else
2161 add_builtin_candidate
2164 }
2167 }
2170 /* If TMPL can be successfully instantiated as indicated by
2171 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2173 TMPL is the template. EXPLICIT_TARGS are any explicit template
2174 arguments. ARGLIST is the arguments provided at the call-site.
2175 The RETURN_TYPE is the desired type for conversion operators. If
2176 OBJ is NULL_TREE, FLAGS and CTYPE are as for add_function_candidate.
2177 If an OBJ is supplied, FLAGS and CTYPE are ignored, and OBJ is as for
2178 add_conv_candidate. */
2185 unification_kind_t strict)
2186 {
2192 tree fn;
2194 /* We don't do deduction on the in-charge parameter, the VTT
2195 parameter or 'this'. */
2205 args_without_in_chrg,
2215 /* In [class.copy]:
2217 A member function template is never instantiated to perform the
2218 copy of a class object to an object of its class type.
2220 It's a little unclear what this means; the standard explicitly
2221 does allow a template to be used to copy a class. For example,
2222 in:
2224 struct A {
2225 A(A&);
2226 template <class T> A(const T&);
2227 };
2228 const A f ();
2229 void g () { A a (f ()); }
2231 the member template will be used to make the copy. The section
2232 quoted above appears in the paragraph that forbids constructors
2233 whose only parameter is (a possibly cv-qualified variant of) the
2234 class type, and a logical interpretation is that the intent was
2235 to forbid the instantiation of member templates which would then
2236 have that form. */
2238 {
2241 ctype))
2243 }
2246 /* Aha, this is a conversion function. */
2249 else
2254 /* This situation can occur if a member template of a template
2255 class is specialized. Then, instantiate_template might return
2256 an instantiation of the specialization, in which case the
2257 DECL_TI_TEMPLATE field will point at the original
2258 specialization. For example:
2260 template <class T> struct S { template <class U> void f(U);
2261 template <> void f(int) {}; };
2262 S<double> sd;
2263 sd.f(3);
2265 Here, TMPL will be template <class U> S<double>::f(U).
2266 And, instantiate template will give us the specialization
2267 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2268 for this will point at template <class T> template <> S<T>::f(int),
2269 so that we can find the definition. For the purposes of
2270 overload resolution, however, we want the original TMPL. */
2272 else
2276 }
2283 unification_kind_t strict)
2284 {
2285 return
2290 }
2297 {
2298 return
2302 }
2304 /* The CANDS are the set of candidates that were considered for
2305 overload resolution. Return the set of viable candidates. If none
2306 of the candidates were viable, set *ANY_VIABLE_P to true. STRICT_P
2307 is true if a candidate should be considered viable only if it is
2308 strictly viable. */
2314 {
2325 {
2328 {
2334 }
2335 else
2337 }
2340 }
2342 static bool
2344 {
2349 }
2351 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2352 words, it is about to become the "this" pointer for a member
2353 function call. Take the address of the object. */
2355 static tree
2357 {
2358 /* In a template, we are only concerned about the type of the
2359 expression, so we can take a shortcut. */
2364 }
2366 /* Returns true iff functions are equivalent. Equivalent functions are
2367 not '==' only if one is a function-local extern function or if
2368 both are extern "C". */
2372 {
2377 }
2379 /* Print information about one overload candidate CANDIDATE. MSGSTR
2380 is the text to print before the candidate itself.
2382 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2383 to have been run through gettext by the caller. This wart makes
2384 life simpler in print_z_candidates and for the translators. */
2386 static void
2388 {
2390 {
2400 else
2403 }
2408 else
2410 }
2412 static void
2414 {
2419 /* There may be duplicates in the set of candidates. We put off
2420 checking this condition as long as possible, since we have no way
2421 to eliminate duplicates from a set of functions in less than n^2
2422 time. Now we are about to emit an error message, so it is more
2423 permissible to go slowly. */
2425 {
2427 /* Skip builtin candidates and conversion functions. */
2432 {
2436 else
2438 }
2439 }
2447 {
2448 /* Indent successive candidates by the width of the translation
2449 of the above string. */
2456 do
2457 {
2460 }
2462 }
2463 }
2465 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2466 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2467 the result of the conversion function to convert it to the final
2468 desired type. Merge the two sequences into a single sequence,
2469 and return the merged sequence. */
2473 {
2478 /* Find the end of the second conversion sequence. */
2483 /* Replace the identity conversion with the user conversion
2484 sequence. */
2487 /* The entire sequence is a user-conversion sequence. */
2491 }
2493 /* Returns the best overload candidate to perform the requested
2494 conversion. This function is used for three the overloading situations
2495 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2496 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2497 per [dcl.init.ref], so we ignore temporary bindings. */
2501 {
2510 /* We represent conversion within a hierarchy using RVALUE_CONV and
2511 BASE_CONV, as specified by [over.best.ics]; these become plain
2512 constructor calls, as specified in [dcl.init]. */
2526 {
2527 tree t;
2533 /* We should never try to call the abstract or base constructor
2534 from here. */
2538 }
2540 {
2550 flags,
2551 DEDUCE_CALL);
2552 else
2556 flags);
2560 }
2566 {
2567 tree fns;
2571 /* If we are called to convert to a reference type, we are trying to
2572 find an lvalue binding, so don't even consider temporaries. If
2573 we don't find an lvalue binding, the caller will try again to
2574 look for a temporary binding. */
2579 {
2582 /* [over.match.funcs] For conversion functions, the function
2583 is considered to be a member of the class of the implicit
2584 object argument for the purpose of defining the type of
2585 the implicit object parameter.
2587 So we pass fromtype as CTYPE to add_*_candidate. */
2591 NULL_TREE,
2594 conversion_path,
2595 flags,
2596 DEDUCE_CONV);
2597 else
2599 args,
2601 conversion_path,
2602 flags);
2605 {
2606 conversion *ics
2618 }
2619 }
2620 }
2628 {
2630 {
2634 }
2641 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
2642 ambiguous conversion is no worse than another user-defined
2643 conversion. */
2646 }
2648 /* Build the user conversion sequence. */
2649 conv = build_conv
2656 /* Combine it with the second conversion sequence. */
2664 }
2666 tree
2668 {
2673 {
2678 }
2680 }
2682 /* Do any initial processing on the arguments to a function call. */
2684 static tree
2686 {
2687 tree t;
2689 {
2695 {
2698 }
2699 }
2701 }
2703 /* Perform overload resolution on FN, which is called with the ARGS.
2705 Return the candidate function selected by overload resolution, or
2706 NULL if the event that overload resolution failed. In the case
2707 that overload resolution fails, *CANDIDATES will be the set of
2708 candidates considered, and ANY_VIABLE_P will be set to true or
2709 false to indicate whether or not any of the candidates were
2710 viable.
2712 The ARGS should already have gone through RESOLVE_ARGS before this
2713 function is called. */
2717 tree args,
2720 {
2728 /* Check FN and ARGS. */
2736 {
2740 }
2742 /* Add the various candidate functions. */
2746 LOOKUP_NORMAL,
2747 candidates);
2755 }
2757 /* Return an expression for a call to FN (a namespace-scope function,
2758 or a static member function) with the ARGS. */
2760 tree
2762 {
2766 tree result;
2772 /* If this function was found without using argument dependent
2773 lookup, then we want to ignore any undeclared friend
2774 functions. */
2776 {
2781 {
2785 }
2786 }
2788 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2794 {
2802 else
2808 }
2809 else
2812 /* Free all the conversions we allocated. */
2816 }
2818 /* Build a call to a global operator new. FNNAME is the name of the
2819 operator (either "operator new" or "operator new[]") and ARGS are
2820 the arguments provided. *SIZE points to the total number of bytes
2821 required by the allocation, and is updated if that is changed here.
2822 *COOKIE_SIZE is non-NULL if a cookie should be used. If this
2823 function determines that no cookie should be used, after all,
2824 *COOKIE_SIZE is set to NULL_TREE. */
2826 tree
2828 {
2829 tree fns;
2839 /* Based on:
2841 [expr.new]
2843 If this lookup fails to find the name, or if the allocated type
2844 is not a class type, the allocation function's name is looked
2845 up in the global scope.
2847 we disregard block-scope declarations of "operator new". */
2850 /* Figure out what function is being called. */
2853 /* If no suitable function could be found, issue an error message
2854 and give up. */
2856 {
2860 else
2866 }
2868 /* If a cookie is required, add some extra space. Whether
2869 or not a cookie is required cannot be determined until
2870 after we know which function was called. */
2872 {
2875 {
2877 /* In G++ 3.2, the check was implemented incorrectly; it
2878 looked at the placement expression, rather than the
2879 type of the function. */
2882 ptr_type_node))
2884 }
2885 else
2886 {
2887 tree arg_types;
2890 /* Skip the size_t parameter. */
2892 /* Check the remaining parameters (if any). */
2896 ptr_type_node))
2898 }
2899 /* If we need a cookie, adjust the number of bytes allocated. */
2901 {
2902 /* Update the total size. */
2904 /* Update the argument list to reflect the adjusted size. */
2906 }
2907 else
2909 }
2911 /* Build the CALL_EXPR. */
2913 }
2915 static tree
2917 {
2926 {
2927 /* It's no good looking for an overloaded operator() on a
2928 pointer-to-member-function. */
2929 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
2931 }
2934 {
2938 }
2939 else
2947 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2951 {
2956 {
2964 else
2965 add_function_candidate
2968 }
2969 }
2974 {
2986 {
2989 add_template_conv_candidate
2993 else
2997 }
2998 }
3002 {
3006 }
3007 else
3008 {
3011 {
3015 }
3016 /* Since cand->fn will be a type, not a function, for a conversion
3017 function, we must be careful not to unconditionally look at
3018 DECL_NAME here. */
3022 else
3023 {
3027 }
3028 }
3030 /* Free all the conversions we allocated. */
3034 }
3036 static void
3039 {
3044 else
3048 {
3072 else
3076 }
3077 }
3079 /* Return the implicit conversion sequence that could be used to
3080 convert E1 to E2 in [expr.cond]. */
3084 {
3090 /* [expr.cond]
3092 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3093 implicitly converted (clause _conv_) to the type "reference to
3094 T2", subject to the constraint that in the conversion the
3095 reference must bind directly (_dcl.init.ref_) to E1. */
3097 {
3099 t1,
3100 e1,
3102 LOOKUP_NO_TEMP_BIND);
3105 }
3107 /* [expr.cond]
3109 If E1 and E2 have class type, and the underlying class types are
3110 the same or one is a base class of the other: E1 can be converted
3111 to match E2 if the class of T2 is the same type as, or a base
3112 class of, the class of T1, and the cv-qualification of T2 is the
3113 same cv-qualification as, or a greater cv-qualification than, the
3114 cv-qualification of T1. If the conversion is applied, E1 is
3115 changed to an rvalue of type T2 that still refers to the original
3116 source class object (or the appropriate subobject thereof). */
3119 {
3121 {
3126 else
3129 }
3130 else
3132 }
3133 else
3134 /* [expr.cond]
3136 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3137 converted to the type that expression E2 would have if E2 were
3138 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3140 LOOKUP_NORMAL);
3141 }
3143 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3144 arguments to the conditional expression. */
3146 tree
3148 {
3149 tree arg2_type;
3150 tree arg3_type;
3158 /* As a G++ extension, the second argument to the conditional can be
3159 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3160 c'.) If the second operand is omitted, make sure it is
3161 calculated only once. */
3163 {
3167 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3170 else
3172 }
3174 /* [expr.cond]
3176 The first expr ession is implicitly converted to bool (clause
3177 _conv_). */
3180 /* If something has already gone wrong, just pass that fact up the
3181 tree. */
3187 /* [expr.cond]
3189 If either the second or the third operand has type (possibly
3190 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3191 array-to-pointer (_conv.array_), and function-to-pointer
3192 (_conv.func_) standard conversions are performed on the second
3193 and third operands. */
3197 {
3198 /* Do the conversions. We don't these for `void' type arguments
3199 since it can't have any effect and since decay_conversion
3200 does not handle that case gracefully. */
3208 /* [expr.cond]
3210 One of the following shall hold:
3212 --The second or the third operand (but not both) is a
3213 throw-expression (_except.throw_); the result is of the
3214 type of the other and is an rvalue.
3216 --Both the second and the third operands have type void; the
3217 result is of type void and is an rvalue.
3219 We must avoid calling force_rvalue for expressions of type
3220 "void" because it will complain that their value is being
3221 used. */
3224 {
3229 }
3232 {
3237 }
3240 else
3241 {
3245 }
3249 }
3250 /* [expr.cond]
3252 Otherwise, if the second and third operand have different types,
3253 and either has (possibly cv-qualified) class type, an attempt is
3254 made to convert each of those operands to the type of the other. */
3257 {
3261 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3267 /* [expr.cond]
3269 If both can be converted, or one can be converted but the
3270 conversion is ambiguous, the program is ill-formed. If
3271 neither can be converted, the operands are left unchanged and
3272 further checking is performed as described below. If exactly
3273 one conversion is possible, that conversion is applied to the
3274 chosen operand and the converted operand is used in place of
3275 the original operand for the remainder of this section. */
3280 {
3284 }
3286 {
3290 }
3292 {
3296 }
3298 /* Free all the conversions we allocated. */
3304 /* If, after the conversion, both operands have class type,
3305 treat the cv-qualification of both operands as if it were the
3306 union of the cv-qualification of the operands.
3308 The standard is not clear about what to do in this
3309 circumstance. For example, if the first operand has type
3310 "const X" and the second operand has a user-defined
3311 conversion to "volatile X", what is the type of the second
3312 operand after this step? Making it be "const X" (matching
3313 the first operand) seems wrong, as that discards the
3314 qualification without actually performing a copy. Leaving it
3315 as "volatile X" seems wrong as that will result in the
3316 conditional expression failing altogether, even though,
3317 according to this step, the one operand could be converted to
3318 the type of the other. */
3326 }
3328 /* [expr.cond]
3330 If the second and third operands are lvalues and have the same
3331 type, the result is of that type and is an lvalue. */
3335 {
3338 }
3340 /* [expr.cond]
3342 Otherwise, the result is an rvalue. If the second and third
3343 operand do not have the same type, and either has (possibly
3344 cv-qualified) class type, overload resolution is used to
3345 determine the conversions (if any) to be applied to the operands
3346 (_over.match.oper_, _over.built_). */
3350 {
3355 /* Rearrange the arguments so that add_builtin_candidate only has
3356 to know about two args. In build_builtin_candidates, the
3357 arguments are unscrambled. */
3362 COND_EXPR,
3363 NOP_EXPR,
3365 args,
3366 LOOKUP_NORMAL);
3368 /* [expr.cond]
3370 If the overload resolution fails, the program is
3371 ill-formed. */
3374 {
3378 }
3381 {
3385 }
3387 /* [expr.cond]
3389 Otherwise, the conversions thus determined are applied, and
3390 the converted operands are used in place of the original
3391 operands for the remainder of this section. */
3398 }
3400 /* [expr.cond]
3402 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3403 and function-to-pointer (_conv.func_) standard conversions are
3404 performed on the second and third operands.
3406 We need to force the lvalue-to-rvalue conversion here for class types,
3407 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3408 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3409 regions. */
3422 /* [expr.cond]
3424 After those conversions, one of the following shall hold:
3426 --The second and third operands have the same type; the result is of
3427 that type. */
3430 /* [expr.cond]
3432 --The second and third operands have arithmetic or enumeration
3433 type; the usual arithmetic conversions are performed to bring
3434 them to a common type, and the result is of that type. */
3439 {
3440 /* In this case, there is always a common type. */
3442 arg3_type);
3457 }
3458 /* [expr.cond]
3460 --The second and third operands have pointer type, or one has
3461 pointer type and the other is a null pointer constant; pointer
3462 conversions (_conv.ptr_) and qualification conversions
3463 (_conv.qual_) are performed to bring them to their composite
3464 pointer type (_expr.rel_). The result is of the composite
3465 pointer type.
3467 --The second and third operands have pointer to member type, or
3468 one has pointer to member type and the other is a null pointer
3469 constant; pointer to member conversions (_conv.mem_) and
3470 qualification conversions (_conv.qual_) are performed to bring
3471 them to a common type, whose cv-qualification shall match the
3472 cv-qualification of either the second or the third operand.
3473 The result is of the common type. */
3481 {
3488 }
3491 {
3495 }
3497 valid_operands:
3500 /* We can't use result_type below, as fold might have returned a
3501 throw_expr. */
3503 /* Expand both sides into the same slot, hopefully the target of the
3504 ?: expression. We used to check for TARGET_EXPRs here, but now we
3505 sometimes wrap them in NOP_EXPRs so the test would fail. */
3509 /* If this expression is an rvalue, but might be mistaken for an
3510 lvalue, we must add a NON_LVALUE_EXPR. */
3515 }
3517 /* OPERAND is an operand to an expression. Perform necessary steps
3518 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
3519 returned. */
3521 static tree
3523 {
3525 {
3528 /* Make sure the template type is instantiated now. */
3530 }
3533 }
3535 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
3536 OVERLOAD) to the CANDIDATES, returning an updated list of
3537 CANDIDATES. The ARGS are the arguments provided to the call,
3538 without any implicit object parameter. The EXPLICIT_TARGS are
3539 explicit template arguments provided. TEMPLATE_ONLY is true if
3540 only template functions should be considered. CONVERSION_PATH,
3541 ACCESS_PATH, and FLAGS are as for add_function_candidate. */
3543 static void
3549 {
3550 tree ctype;
3551 tree non_static_args;
3554 /* Delay creating the implicit this parameter until it is needed. */
3558 {
3559 tree fn;
3560 tree fn_args;
3563 /* Figure out which set of arguments to use. */
3565 {
3566 /* If this function is a non-static member, prepend the implicit
3567 object parameter. */
3573 }
3574 else
3575 /* Otherwise, just use the list of arguments provided. */
3580 fn,
3581 ctype,
3582 explicit_targs,
3583 fn_args,
3584 NULL_TREE,
3585 access_path,
3586 conversion_path,
3587 flags,
3588 DEDUCE_CALL);
3591 fn,
3592 ctype,
3593 fn_args,
3594 access_path,
3595 conversion_path,
3596 flags);
3598 }
3599 }
3601 tree
3604 {
3622 {
3626 }
3627 else
3633 {
3638 /* Use build_op_new_call and build_op_delete_call instead. */
3646 }
3652 {
3659 }
3674 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3677 /* Add namespace-scope operators to the list of functions to
3678 consider. */
3682 /* Add class-member operators to the candidate set. */
3684 {
3685 tree fns;
3689 {
3692 }
3699 }
3701 /* Rearrange the arguments for ?: so that add_builtin_candidate only has
3702 to know about two args; a builtin candidate will always have a first
3703 parameter of type bool. We'll handle that in
3704 build_builtin_candidate. */
3706 {
3710 }
3711 else
3712 {
3716 }
3721 {
3724 /* For these, the built-in candidates set is empty
3725 [over.match.oper]/3. We don't want non-strict matches
3726 because exact matches are always possible with built-in
3727 operators. The built-in candidate set for COMPONENT_REF
3728 would be empty too, but since there are no such built-in
3729 operators, we accept non-strict matches for them. */
3736 }
3740 {
3742 {
3745 /* Look for an `operator++ (int)'. If they didn't have
3746 one, then we fall back to the old way of doing things. */
3750 fnname,
3754 else
3757 overloaded_p);
3760 /* The caller will deal with these. */
3770 {
3773 }
3776 }
3777 }
3778 else
3779 {
3782 {
3784 {
3787 }
3789 }
3791 {
3796 }
3797 else
3798 {
3799 /* Give any warnings we noticed during overload resolution. */
3801 {
3805 }
3807 /* Check for comparison of different enum types. */
3809 {
3820 {
3823 }
3827 }
3829 /* We need to strip any leading REF_BIND so that bitfields
3830 don't cause errors. This should not remove any important
3831 conversions, because builtins don't apply to class
3832 objects directly. */
3838 {
3843 }
3845 {
3850 }
3851 }
3852 }
3854 user_defined_result_ready:
3856 /* Free all the conversions we allocated. */
3862 builtin:
3864 {
3914 /* The caller will deal with these. */
3922 }
3924 }
3926 /* Build a call to operator delete. This has to be handled very specially,
3927 because the restrictions on what signatures match are different from all
3928 other call instances. For a normal delete, only a delete taking (void *)
3929 or (void *, size_t) is accepted. For a placement delete, only an exact
3930 match with the placement new is accepted.
3932 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
3933 ADDR is the pointer to be deleted.
3934 SIZE is the size of the memory block to be deleted.
3935 GLOBAL_P is true if the delete-expression should not consider
3936 class-specific delete operators.
3937 PLACEMENT is the corresponding placement new call, or NULL_TREE. */
3939 tree
3942 {
3957 /* In [class.free]
3959 If the result of the lookup is ambiguous or inaccessible, or if
3960 the lookup selects a placement deallocation function, the
3961 program is ill-formed.
3963 Therefore, we ask lookup_fnfields to complain about ambiguity. */
3964 {
3968 }
3969 else
3976 {
3977 tree alloc_fn;
3978 tree call_expr;
3980 /* Find the allocation function that is being called. */
3982 /* Extract the function. */
3985 /* Then the second parm type. */
3987 /* Also the second argument. */
3989 }
3990 else
3991 {
3992 /* First try it without the size argument. */
3995 }
3997 /* Strip const and volatile from addr. */
4000 /* We make two tries at finding a matching `operator delete'. On
4001 the first pass, we look for a one-operator (or placement)
4002 operator delete. If we're not doing placement delete, then on
4003 the second pass we look for a two-argument delete. */
4005 {
4006 /* Go through the `operator delete' functions looking for one
4007 with a matching type. */
4009 fn;
4011 {
4012 tree t;
4014 /* The first argument must be "void *". */
4019 /* On the first pass, check the rest of the arguments. */
4021 {
4024 {
4029 }
4032 }
4033 /* On the second pass, the second argument must be
4034 "size_t". */
4039 }
4041 /* If we found a match, we're done. */
4044 }
4046 /* If we have a matching function, call it. */
4048 {
4049 /* Make sure we have the actual function, and not an
4050 OVERLOAD. */
4053 /* If the FN is a member function, make sure that it is
4054 accessible. */
4060 else
4065 {
4066 /* The placement args might not be suitable for overload
4067 resolution at this point, so build the call directly. */
4070 }
4071 else
4073 }
4075 /* If we are doing placement delete we do nothing if we don't find a
4076 matching op delete. */
4083 }
4085 /* If the current scope isn't allowed to access DECL along
4086 BASETYPE_PATH, give an error. The most derived class in
4087 BASETYPE_PATH is the one used to qualify DECL. */
4089 bool
4091 {
4095 {
4100 else
4104 }
4107 }
4109 /* Check that a callable constructor to initialize a temporary of
4110 TYPE from an EXPR exists. */
4112 static void
4114 {
4116 complete_ctor_identifier,
4118 type,
4119 LOOKUP_NORMAL | LOOKUP_ONLYCONVERTING
4120 | LOOKUP_NO_CONVERSION
4122 }
4124 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
4125 bitwise or of LOOKUP_* values. If any errors are warnings are
4126 generated, set *DIAGNOSTIC_FN to "error" or "warning",
4127 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
4128 to NULL. */
4130 static tree
4133 {
4138 complete_ctor_identifier,
4145 else
4148 }
4151 /* Perform the conversions in CONVS on the expression EXPR. FN and
4152 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4153 indicates the `this' argument of a method. INNER is nonzero when
4154 being called to continue a conversion chain. It is negative when a
4155 reference binding will be applied, positive otherwise. If
4156 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
4157 conversions will be emitted if appropriate. If C_CAST_P is true,
4158 this conversion is coming from a C-style cast; in that case,
4159 conversions to inaccessible bases are permitted. */
4161 static tree
4165 {
4167 diagnostic_fn_t diagnostic_fn;
4173 {
4176 {
4178 {
4183 }
4190 }
4195 }
4198 {
4201 /* Issue warnings about peculiar, but valid, uses of NULL. */
4203 {
4207 else
4209 }
4211 /* Warn about assigning a floating-point type to an integer type. */
4214 {
4218 else
4220 }
4221 }
4224 {
4226 {
4229 tree args;
4232 {
4237 /* We should never try to call the abstract or base constructor
4238 from here. */
4242 }
4243 else
4247 /* If this is a constructor or a function returning an aggr type,
4248 we need to build up a TARGET_EXPR. */
4252 /* The result of the call is then used to direct-initialize the object
4253 that is the destination of the copy-initialization. [dcl.init]
4255 Note that this step is not reflected in the conversion sequence;
4256 it affects the semantics when we actually perform the
4257 conversion, but is not considered during overload resolution.
4259 If the target is a class, that means call a ctor. */
4262 {
4263 expr = (build_temp
4265 /* Core issue 84, now a DR, says that we don't
4266 allow UDCs for these args (which deliberately
4267 breaks copy-init of an auto_ptr<Base> from an
4268 auto_ptr<Derived>). */
4273 {
4275 diagnostic_fn
4278 else
4279 diagnostic_fn
4281 }
4283 }
4285 }
4289 /* Convert a constant to its underlying value, unless we are
4290 about to bind it to a reference, in which case we need to
4291 leave it as an lvalue. */
4298 /* Call build_user_type_conversion again for the error. */
4299 return build_user_type_conversion
4304 };
4309 c_cast_p);
4314 {
4318 /* Else fall through. */
4321 {
4322 /* We are going to bind a reference directly to a base-class
4323 subobject of EXPR. */
4326 /* Build an expression for `*((base*) &expr)'. */
4332 }
4334 /* Copy-initialization where the cv-unqualified version of the source
4335 type is the same class as, or a derived class of, the class of the
4336 destination [is treated as direct-initialization]. [dcl.init] */
4344 {
4347 /* If necessary, create a temporary. */
4349 {
4354 {
4355 /* If the reference is volatile or non-const, we
4356 cannot create a temporary. */
4363 else
4366 }
4367 /* If the source is a packed field, and we must use a copy
4368 constructor, then building the target expr will require
4369 binding the field to the reference parameter to the
4370 copy constructor, and we'll end up with an infinite
4371 loop. If we can use a bitwise copy, then we'll be
4372 OK. */
4376 {
4380 }
4382 }
4384 /* Take the address of the thing to which we will bind the
4385 reference. */
4390 /* Convert it to a pointer to the type referred to by the
4391 reference. This will adjust the pointer if a derived to
4392 base conversion is being performed. */
4394 expr);
4395 /* Convert the pointer to the desired reference type. */
4397 }
4403 /* Warn about deprecated conversion if appropriate. */
4415 c_cast_p);
4419 }
4423 else
4427 }
4429 /* Build a call to __builtin_trap. */
4431 static tree
4433 {
4439 }
4441 /* ARG is being passed to a varargs function. Perform any conversions
4442 required. Return the converted value. */
4444 tree
4446 {
4447 /* [expr.call]
4449 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
4450 standard conversions are performed. */
4452 /* [expr.call]
4454 If the argument has integral or enumeration type that is subject
4455 to the integral promotions (_conv.prom_), or a floating point
4456 type that is subject to the floating point promotion
4457 (_conv.fpprom_), the value of the argument is converted to the
4458 promoted type before the call. */
4470 {
4471 /* Undefined behavior [expr.call] 5.2.2/7. We used to just warn
4472 here and do a bitwise copy, but now cp_expr_size will abort if we
4473 try to do that.
4474 If the call appears in the context of a sizeof expression,
4475 there is no need to emit a warning, since the expression won't be
4476 evaluated. We keep the builtin_trap just as a safety check. */
4482 integer_zero_node);
4483 }
4486 }
4488 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
4490 tree
4492 {
4502 {
4503 /* Undefined behavior [expr.call] 5.2.2/7. */
4511 }
4514 }
4516 /* TYPE has been given to va_arg. Apply the default conversions which
4517 would have happened when passed via ellipsis. Return the promoted
4518 type, or the passed type if there is no change. */
4520 tree
4522 {
4523 tree promote;
4525 /* Perform the array-to-pointer and function-to-pointer
4526 conversions. */
4534 }
4536 /* ARG is a default argument expression being passed to a parameter of
4537 the indicated TYPE, which is a parameter to FN. Do any required
4538 conversions. Return the converted value. */
4540 tree
4542 {
4543 /* If the ARG is an unparsed default argument expression, the
4544 conversion cannot be performed. */
4546 {
4551 }
4559 {
4563 }
4564 else
4565 {
4566 /* This could get clobbered by the following call. */
4573 }
4576 }
4578 /* Returns the type which will really be used for passing an argument of
4579 type TYPE. */
4581 tree
4583 {
4584 /* Pass classes with copy ctors by invisible reference. */
4586 {
4588 /* There are no other pointers to this temporary. */
4590 }
4599 }
4601 /* Actually perform the appropriate conversion. */
4603 tree
4605 {
4607 ;
4608 /* Pass classes with copy ctors by invisible reference. */
4618 {
4627 }
4629 }
4631 /* Returns true iff FN is a function with magic varargs, i.e. ones for
4632 which no conversions at all should be done. This is true for some
4633 builtins which don't act like normal functions. */
4635 static bool
4637 {
4640 {
4649 }
4652 }
4654 /* Subroutine of the various build_*_call functions. Overload resolution
4655 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
4656 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
4657 bitmask of various LOOKUP_* flags which apply to the call itself. */
4659 static tree
4661 {
4672 /* In a template, there is no need to perform all of the work that
4673 is normally done. We are only interested in the type of the call
4674 expression, i.e., the return type of the function. Any semantic
4675 errors will be deferred until the template is instantiated. */
4677 {
4678 tree expr;
4679 tree return_type;
4687 }
4689 /* Give any warnings we noticed during overload resolution. */
4691 {
4695 }
4698 {
4699 /* If FN is a template function, two cases must be considered.
4700 For example:
4702 struct A {
4703 protected:
4704 template <class T> void f();
4705 };
4706 template <class T> struct B {
4707 protected:
4708 void g();
4709 };
4710 struct C : A, B<int> {
4711 using A::f; // #1
4712 using B<int>::g; // #2
4713 };
4715 In case #1 where `A::f' is a member template, DECL_ACCESS is
4716 recorded in the primary template but not in its specialization.
4717 We check access of FN using its primary template.
4719 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
4720 because it is a member of class template B, DECL_ACCESS is
4721 recorded in the specialization `B<int>::g'. We cannot use its
4722 primary template because `B<T>::g' and `B<int>::g' may have
4723 different access. */
4728 else
4730 }
4736 /* The implicit parameters to a constructor are not considered by overload
4737 resolution, and must be of the proper type. */
4739 {
4743 /* We should never try to call the abstract constructor. */
4747 {
4748 converted_args = tree_cons
4752 }
4753 }
4754 /* Bypass access control for 'this' parameter. */
4756 {
4759 tree converted_arg;
4760 tree base_binfo;
4766 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
4767 X is called for an object that is not of type X, or of a type
4768 derived from X, the behavior is undefined.
4770 So we can assume that anything passed as 'this' is non-null, and
4771 optimize accordingly. */
4773 /* Convert to the base in which the function was declared. */
4779 /* Check that the base class is accessible. */
4785 /* If fn was found by a using declaration, the conversion path
4786 will be to the derived class, not the base declaring fn. We
4787 must convert from derived to base. */
4798 }
4802 {
4806 val = convert_like_with_context
4811 }
4813 /* Default arguments */
4815 converted_args
4820 converted_args);
4822 /* Ellipsis */
4824 {
4828 else
4831 }
4838 /* Avoid actually calling copy constructors and copy assignment operators,
4839 if possible. */
4844 {
4845 tree targ;
4849 /* Pull out the real argument, disregarding const-correctness. */
4856 {
4861 }
4862 else
4867 else
4870 /* [class.copy]: the copy constructor is implicitly defined even if
4871 the implementation elided its use. */
4875 /* If we're creating a temp and we already have one, don't create a
4876 new one. If we're not creating a temp but we get one, use
4877 INIT_EXPR to collapse the temp into our target. Otherwise, if the
4878 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
4879 temp or an INIT_EXPR otherwise. */
4881 {
4886 }
4889 {
4890 tree to = stabilize_reference
4895 }
4896 }
4900 {
4901 tree to = stabilize_reference
4908 {
4911 }
4912 else
4913 {
4914 /* We must only copy the non-tail padding parts.
4915 Use __builtin_memcpy for the bitwise copy. */
4928 }
4931 }
4936 {
4949 else
4952 }
4955 else
4959 }
4961 /* Build and return a call to FN, using ARGS. This function performs
4962 no overload resolution, conversion, or other high-level
4963 operations. */
4965 tree
4967 {
4968 tree fndecl;
4972 /* If this call might throw an exception, note that fact. */
4979 /* Some built-in function calls will be evaluated at compile-time in
4980 fold (). */
4993 }
4997 /* Make an expression which yields the address of the Java interface
4998 method FN. This is achieved by generating a call to libjava's
4999 _Jv_LookupInterfaceMethodIdx(). */
5001 static tree
5003 {
5009 {
5014 endlink)));
5015 java_iface_lookup_fn
5019 }
5021 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
5022 This is the first entry in the vtable. */
5024 integer_zero_node);
5026 /* Get the java.lang.Class pointer for the interface being called. */
5031 {
5033 iface);
5035 }
5039 /* Determine the itable index of FN. */
5042 {
5047 i++;
5048 }
5056 java_iface_lookup_fn);
5058 }
5060 /* Returns the value to use for the in-charge parameter when making a
5061 call to a function with the indicated NAME.
5063 FIXME:Can't we find a neater way to do this mapping? */
5065 tree
5067 {
5078 /* This function should only be called with one of the names listed
5079 above. */
5082 }
5084 /* Build a call to a constructor, destructor, or an assignment
5085 operator for INSTANCE, an expression with class type. NAME
5086 indicates the special member function to call; ARGS are the
5087 arguments. BINFO indicates the base of INSTANCE that is to be
5088 passed as the `this' parameter to the member function called.
5090 FLAGS are the LOOKUP_* flags to use when processing the call.
5092 If NAME indicates a complete object constructor, INSTANCE may be
5093 NULL_TREE. In this case, the caller will call build_cplus_new to
5094 store the newly constructed object into a VAR_DECL. */
5096 tree
5099 {
5100 tree fns;
5101 /* The type of the subobject to be constructed or destroyed. */
5102 tree class_type;
5111 {
5112 /* Resolve the name. */
5117 }
5123 /* Handle the special case where INSTANCE is NULL_TREE. */
5125 {
5128 }
5129 else
5130 {
5136 /* Convert to the base class, if necessary. */
5139 {
5141 /* For constructors and destructors, either the base is
5142 non-virtual, or it is virtual but we are doing the
5143 conversion from a constructor or destructor for the
5144 complete object. In either case, we can convert
5145 statically. */
5147 else
5148 /* However, for assignment operators, we must convert
5149 dynamically if the base is virtual. */
5152 }
5153 }
5159 /* When making a call to a constructor or destructor for a subobject
5160 that uses virtual base classes, pass down a pointer to a VTT for
5161 the subobject. */
5165 {
5166 tree vtt;
5167 tree sub_vtt;
5169 /* If the current function is a complete object constructor
5170 or destructor, then we fetch the VTT directly.
5171 Otherwise, we look it up using the VTT we were given. */
5177 current_vtt_parm,
5178 vtt);
5184 }
5188 flags);
5189 }
5191 /* Return the NAME, as a C string. The NAME indicates a function that
5192 is a member of TYPE. *FREE_P is set to true if the caller must
5193 free the memory returned.
5195 Rather than go through all of this, we should simply set the names
5196 of constructors and destructors appropriately, and dispense with
5197 ctor_identifier, dtor_identifier, etc. */
5201 {
5204 /* Assume that we will not allocate memory. */
5206 /* Constructors and destructors are special. */
5208 {
5209 pretty_name
5211 /* For a destructor, add the '~'. */
5215 {
5217 /* Remember that we need to free the memory allocated. */
5219 }
5220 }
5222 {
5225 TFF_PLAIN_IDENTIFIER),
5226 NULL);
5227 /* Remember that we need to free the memory allocated. */
5229 }
5230 else
5234 }
5236 /* Build a call to "INSTANCE.FN (ARGS)". */
5238 tree
5241 {
5245 tree access_binfo;
5246 tree optype;
5248 tree name;
5249 tree user_args;
5250 tree call;
5251 tree fn;
5252 tree class_type;
5255 tree orig_instance;
5256 tree orig_fns;
5257 tree orig_args;
5268 {
5271 }
5277 /* Dismantle the baselink to collect all the information we need. */
5284 {
5288 }
5299 {
5302 }
5304 /* The USER_ARGS are the arguments we will display to users if an
5305 error occurs. The USER_ARGS should not include any
5306 compiler-generated arguments. The "this" pointer hasn't been
5307 added yet. However, we must remove the VTT pointer if this is a
5308 call to a base-class constructor or destructor. */
5311 {
5312 /* Callers should explicitly indicate whether they want to construct
5313 the complete object or just the part without virtual bases. */
5315 /* Similarly for destructors. */
5317 /* Remove the VTT pointer, if present. */
5321 }
5323 /* Process the argument list. */
5330 /* It's OK to call destructors on cv-qualified objects. Therefore,
5331 convert the INSTANCE_PTR to the unqualified type, if necessary. */
5333 {
5338 }
5343 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5347 {
5349 tree this_arglist;
5351 /* We can end up here for copy-init of same or base class. */
5358 else
5362 /* A member template. */
5364 class_type,
5365 explicit_targs,
5367 access_binfo,
5368 conversion_path,
5369 flags,
5370 DEDUCE_CALL);
5373 class_type,
5374 this_arglist,
5375 access_binfo,
5376 conversion_path,
5377 flags);
5378 }
5382 {
5385 else
5386 {
5396 }
5399 }
5400 else
5401 {
5404 {
5410 user_args);
5415 }
5416 else
5417 {
5423 /* This is not an error, it is runtime undefined
5424 behavior. */
5426 "abstract virtual %q#D called from constructor"
5432 {
5436 }
5437 else
5438 {
5445 /* In an expression of the form `a->f()' where `f' turns
5446 out to be a static member function, `a' is
5447 none-the-less evaluated. */
5453 }
5454 }
5455 }
5458 call = (build_min_non_dep
5463 /* Free all the conversions we allocated. */
5467 }
5469 /* Returns true iff standard conversion sequence ICS1 is a proper
5470 subsequence of ICS2. */
5472 static bool
5474 {
5475 /* We can assume that a conversion of the same code
5476 between the same types indicates a subsequence since we only get
5477 here if the types we are converting from are the same. */
5484 {
5492 /* At this point, ICS1 cannot be a proper subsequence of
5493 ICS2. We can get a USER_CONV when we are comparing the
5494 second standard conversion sequence of two user conversion
5495 sequences. */
5505 }
5506 }
5508 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
5509 be any _TYPE nodes. */
5511 bool
5513 {
5518 /* We only allow proper derivation here. The DERIVED_FROM_P macro
5519 considers every class derived from itself. */
5522 }
5524 /* We build the ICS for an implicit object parameter as a pointer
5525 conversion sequence. However, such a sequence should be compared
5526 as if it were a reference conversion sequence. If ICS is the
5527 implicit conversion sequence for an implicit object parameter,
5528 modify it accordingly. */
5530 static void
5532 {
5534 {
5535 /* [over.match.funcs]
5537 For non-static member functions, the type of the
5538 implicit object parameter is "reference to cv X"
5539 where X is the class of which the function is a
5540 member and cv is the cv-qualification on the member
5541 function declaration. */
5543 tree reference_type;
5545 /* The `this' parameter is a pointer to a class type. Make the
5546 implicit conversion talk about a reference to that same class
5547 type. */
5558 }
5559 }
5561 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
5562 and return the type to which the reference refers. Otherwise,
5563 leave *ICS unchanged and return NULL_TREE. */
5565 static tree
5567 {
5569 {
5576 }
5579 }
5581 /* Compare two implicit conversion sequences according to the rules set out in
5582 [over.ics.rank]. Return values:
5584 1: ics1 is better than ics2
5585 -1: ics2 is better than ics1
5586 0: ics1 and ics2 are indistinguishable */
5588 static int
5590 {
5591 tree from_type1;
5592 tree from_type2;
5593 tree to_type1;
5594 tree to_type2;
5601 /* REF_BINDING is nonzero if the result of the conversion sequence
5602 is a reference type. In that case TARGET_TYPE is the
5603 type referred to by the reference. */
5604 tree target_type1;
5605 tree target_type2;
5607 /* Handle implicit object parameters. */
5611 /* Handle reference parameters. */
5615 /* [over.ics.rank]
5617 When comparing the basic forms of implicit conversion sequences (as
5618 defined in _over.best.ics_)
5620 --a standard conversion sequence (_over.ics.scs_) is a better
5621 conversion sequence than a user-defined conversion sequence
5622 or an ellipsis conversion sequence, and
5624 --a user-defined conversion sequence (_over.ics.user_) is a
5625 better conversion sequence than an ellipsis conversion sequence
5626 (_over.ics.ellipsis_). */
5636 {
5637 /* XXX Isn't this an extension? */
5638 /* Both ICS are bad. We try to make a decision based on what
5639 would have happened if they'd been good. */
5647 /* We couldn't make up our minds; try to figure it out below. */
5648 }
5651 /* Both conversions are ellipsis conversions. */
5654 /* User-defined conversion sequence U1 is a better conversion sequence
5655 than another user-defined conversion sequence U2 if they contain the
5656 same user-defined conversion operator or constructor and if the sec-
5657 ond standard conversion sequence of U1 is better than the second
5658 standard conversion sequence of U2. */
5661 {
5675 /* We can just fall through here, after setting up
5676 FROM_TYPE1 and FROM_TYPE2. */
5679 }
5680 else
5681 {
5685 /* We're dealing with two standard conversion sequences.
5687 [over.ics.rank]
5689 Standard conversion sequence S1 is a better conversion
5690 sequence than standard conversion sequence S2 if
5692 --S1 is a proper subsequence of S2 (comparing the conversion
5693 sequences in the canonical form defined by _over.ics.scs_,
5694 excluding any Lvalue Transformation; the identity
5695 conversion sequence is considered to be a subsequence of
5696 any non-identity conversion sequence */
5707 }
5710 {
5715 }
5716 /* Otherwise, one sequence cannot be a subsequence of the other; they
5717 don't start with the same type. This can happen when comparing the
5718 second standard conversion sequence in two user-defined conversion
5719 sequences. */
5721 /* [over.ics.rank]
5723 Or, if not that,
5725 --the rank of S1 is better than the rank of S2 (by the rules
5726 defined below):
5728 Standard conversion sequences are ordered by their ranks: an Exact
5729 Match is a better conversion than a Promotion, which is a better
5730 conversion than a Conversion.
5732 Two conversion sequences with the same rank are indistinguishable
5733 unless one of the following rules applies:
5735 --A conversion that is not a conversion of a pointer, or pointer
5736 to member, to bool is better than another conversion that is such
5737 a conversion.
5739 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
5740 so that we do not have to check it explicitly. */
5753 {
5758 }
5759 /* The rules for pointers to members A::* are just like the rules
5760 for pointers A*, except opposite: if B is derived from A then
5761 A::* converts to B::*, not vice versa. For that reason, we
5762 switch the from_ and to_ variables here. */
5769 {
5774 }
5779 {
5780 /* This was one of the pointer or pointer-like conversions.
5782 [over.ics.rank]
5784 --If class B is derived directly or indirectly from class A,
5785 conversion of B* to A* is better than conversion of B* to
5786 void*, and conversion of A* to void* is better than
5787 conversion of B* to void*. */
5790 {
5792 deref_from_type2))
5795 deref_from_type1))
5797 }
5800 {
5802 {
5804 {
5806 deref_to_type1))
5808 }
5809 /* We know that DEREF_TO_TYPE1 is `void' here. */
5811 deref_to_type2))
5813 }
5814 }
5817 {
5818 /* [over.ics.rank]
5820 --If class B is derived directly or indirectly from class A
5821 and class C is derived directly or indirectly from B,
5823 --conversion of C* to B* is better than conversion of C* to
5824 A*,
5826 --conversion of B* to A* is better than conversion of C* to
5827 A* */
5829 {
5831 deref_to_type2))
5834 deref_to_type1))
5836 }
5838 {
5840 deref_from_type1))
5843 deref_from_type2))
5845 }
5846 }
5847 }
5850 {
5853 /* [over.ics.rank]
5855 --binding of an expression of type C to a reference of type
5856 B& is better than binding an expression of type C to a
5857 reference of type A&
5859 --conversion of C to B is better than conversion of C to A, */
5862 {
5867 }
5868 }
5871 {
5874 /* [over.ics.rank]
5876 --binding of an expression of type B to a reference of type
5877 A& is better than binding an expression of type C to a
5878 reference of type A&,
5880 --conversion of B to A is better than conversion of C to A */
5883 {
5888 }
5889 }
5891 /* [over.ics.rank]
5893 --S1 and S2 differ only in their qualification conversion and yield
5894 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
5895 qualification signature of type T1 is a proper subset of the cv-
5896 qualification signature of type T2 */
5902 /* [over.ics.rank]
5904 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
5905 types to which the references refer are the same type except for
5906 top-level cv-qualifiers, and the type to which the reference
5907 initialized by S2 refers is more cv-qualified than the type to
5908 which the reference initialized by S1 refers */
5914 /* Neither conversion sequence is better than the other. */
5916 }
5918 /* The source type for this standard conversion sequence. */
5920 static tree
5922 {
5924 {
5929 }
5931 }
5933 /* Note a warning about preferring WINNER to LOSER. We do this by storing
5934 a pointer to LOSER and re-running joust to produce the warning if WINNER
5935 is actually used. */
5937 static void
5939 {
5946 }
5948 /* Compare two candidates for overloading as described in
5949 [over.match.best]. Return values:
5951 1: cand1 is better than cand2
5952 -1: cand2 is better than cand1
5953 0: cand1 and cand2 are indistinguishable */
5955 static int
5957 {
5963 /* Candidates that involve bad conversions are always worse than those
5964 that don't. */
5970 /* If we have two pseudo-candidates for conversions to the same type,
5971 or two candidates for the same function, arbitrarily pick one. */
5976 /* a viable function F1
5977 is defined to be a better function than another viable function F2 if
5978 for all arguments i, ICSi(F1) is not a worse conversion sequence than
5979 ICSi(F2), and then */
5981 /* for some argument j, ICSj(F1) is a better conversion sequence than
5982 ICSj(F2) */
5984 /* For comparing static and non-static member functions, we ignore
5985 the implicit object parameter of the non-static function. The
5986 standard says to pretend that the static function has an object
5987 parm, but that won't work with operator overloading. */
5990 {
5998 else
5999 {
6002 }
6003 }
6006 {
6012 {
6025 {
6032 else
6037 {
6041 }
6042 else
6044 }
6047 {
6050 }
6052 }
6053 }
6055 /* warn about confusing overload resolution for user-defined conversions,
6056 either between a constructor and a conversion op, or between two
6057 conversion ops. */
6061 {
6067 else
6070 /* We don't want to complain about `X::operator T1 ()'
6071 beating `X::operator T2 () const', when T2 is a no less
6072 cv-qualified version of T1. */
6075 {
6080 {
6083 }
6086 }
6087 else
6093 {
6101 }
6102 else
6104 }
6109 /* or, if not that,
6110 F1 is a non-template function and F2 is a template function
6111 specialization. */
6118 /* or, if not that,
6119 F1 and F2 are template functions and the function template for F1 is
6120 more specialized than the template for F2 according to the partial
6121 ordering rules. */
6124 {
6125 winner = more_specialized_fn
6128 /* [temp.func.order]: The presence of unused ellipsis and default
6129 arguments has no effect on the partial ordering of function
6130 templates. add_function_candidate() will not have
6131 counted the "this" argument for constructors. */
6135 }
6137 /* or, if not that,
6138 the context is an initialization by user-defined conversion (see
6139 _dcl.init_ and _over.match.user_) and the standard conversion
6140 sequence from the return type of F1 to the destination type (i.e.,
6141 the type of the entity being initialized) is a better conversion
6142 sequence than the standard conversion sequence from the return type
6143 of F2 to the destination type. */
6146 {
6150 }
6152 /* Check whether we can discard a builtin candidate, either because we
6153 have two identical ones or matching builtin and non-builtin candidates.
6155 (Pedantically in the latter case the builtin which matched the user
6156 function should not be added to the overload set, but we spot it here.
6158 [over.match.oper]
6159 ... the builtin candidates include ...
6160 - do not have the same parameter type list as any non-template
6161 non-member candidate. */
6165 {
6171 {
6173 /* Two built-in candidates; arbitrarily pick one. */
6176 /* cand1 is built-in; prefer cand2. */
6178 else
6179 /* cand2 is built-in; prefer cand1. */
6181 }
6182 }
6184 /* If the two functions are the same (this can happen with declarations
6185 in multiple scopes and arg-dependent lookup), arbitrarily choose one. */
6190 tweak:
6192 /* Extension: If the worst conversion for one candidate is worse than the
6193 worst conversion for the other, take the first. */
6195 {
6200 {
6205 }
6211 {
6213 {
6215 ISO C++ says that these are ambiguous, even \
6216 though the worst conversion for the first is better than \
6220 }
6221 else
6224 }
6225 }
6229 }
6231 /* Given a list of candidates for overloading, find the best one, if any.
6232 This algorithm has a worst case of O(2n) (winner is last), and a best
6233 case of O(n/2) (totally ambiguous); much better than a sorting
6234 algorithm. */
6238 {
6243 /* Walk through the list once, comparing each current champ to the next
6244 candidate, knocking out a candidate or two with each comparison. */
6247 {
6251 else
6252 {
6254 {
6259 }
6260 else
6261 {
6264 }
6267 }
6268 }
6270 /* Make sure the champ is better than all the candidates it hasn't yet
6271 been compared to. */
6274 challenger != champ
6277 {
6281 }
6284 }
6286 /* Returns nonzero if things of type FROM can be converted to TO. */
6288 bool
6290 {
6292 }
6294 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
6296 bool
6298 {
6303 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6307 flags);
6310 /* Free all the conversions we allocated. */
6314 }
6316 /* Like can_convert_arg, but allows dubious conversions as well. */
6318 bool
6320 {
6324 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6326 /* Try to perform the conversion. */
6328 LOOKUP_NORMAL);
6329 /* Free all the conversions we allocated. */
6333 }
6335 /* Convert EXPR to TYPE. Return the converted expression.
6337 Note that we allow bad conversions here because by the time we get to
6338 this point we are committed to doing the conversion. If we end up
6339 doing a bad conversion, convert_like will complain. */
6341 tree
6343 {
6350 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6355 LOOKUP_NORMAL);
6357 {
6360 }
6361 else
6364 /* Free all the conversions we allocated. */
6368 }
6370 /* Convert EXPR to TYPE (as a direct-initialization) if that is
6371 permitted. If the conversion is valid, the converted expression is
6372 returned. Otherwise, NULL_TREE is returned, except in the case
6373 that TYPE is a class type; in that case, an error is issued. If
6374 C_CAST_P is true, then this direction initialization is taking
6375 place as part of a static_cast being attempted as part of a C-style
6376 cast. */
6378 tree
6380 tree expr,
6382 {
6388 /* [dcl.init]
6390 If the destination type is a (possibly cv-qualified) class type:
6392 -- If the initialization is direct-initialization ...,
6393 constructors are considered. ... If no constructor applies, or
6394 the overload resolution is ambiguous, the initialization is
6395 ill-formed. */
6397 {
6402 }
6404 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6408 c_cast_p,
6409 LOOKUP_NORMAL);
6412 else
6415 c_cast_p);
6417 /* Free all the conversions we allocated. */
6421 }
6423 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
6424 is being bound to a temporary. Create and return a new VAR_DECL
6425 with the indicated TYPE; this variable will store the value to
6426 which the reference is bound. */
6428 tree
6430 {
6431 tree var;
6433 /* Create the variable. */
6439 /* Register the variable. */
6441 {
6442 /* Namespace-scope or local static; give it a mangled name. */
6443 tree name;
6450 }
6451 else
6452 {
6453 /* Create a new cleanup level if necessary. */
6455 /* Don't push unnamed temps. Do set DECL_CONTEXT, though. */
6457 }
6460 }
6462 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
6463 initializing a variable of that TYPE. If DECL is non-NULL, it is
6464 the VAR_DECL being initialized with the EXPR. (In that case, the
6465 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
6466 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
6467 return, if *CLEANUP is no longer NULL, it will be an expression
6468 that should be pushed as a cleanup after the returned expression
6469 is used to initialize DECL.
6471 Return the converted expression. */
6473 tree
6475 {
6482 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6487 {
6493 else
6498 }
6500 /* If DECL is non-NULL, then this special rule applies:
6502 [class.temporary]
6504 The temporary to which the reference is bound or the temporary
6505 that is the complete object to which the reference is bound
6506 persists for the lifetime of the reference.
6508 The temporaries created during the evaluation of the expression
6509 initializing the reference, except the temporary to which the
6510 reference is bound, are destroyed at the end of the
6511 full-expression in which they are created.
6513 In that case, we store the converted expression into a new
6514 VAR_DECL in a new scope.
6516 However, we want to be careful not to create temporaries when
6517 they are not required. For example, given:
6519 struct B {};
6520 struct D : public B {};
6521 D f();
6522 const B& b = f();
6524 there is no need to copy the return value from "f"; we can just
6525 extend its lifetime. Similarly, given:
6527 struct S {};
6528 struct T { operator S(); };
6529 T t;
6530 const S& s = t;
6532 we can extend the lifetime of the return value of the conversion
6533 operator. */
6536 {
6537 tree var;
6538 tree base_conv_type;
6540 /* Skip over the REF_BIND. */
6542 /* If the next conversion is a BASE_CONV, skip that too -- but
6543 remember that the conversion was required. */
6545 {
6550 }
6551 else
6553 /* Perform the remainder of the conversion. */
6561 else
6562 {
6564 {
6565 tree init;
6566 tree type;
6568 /* Create the temporary variable. */
6572 /* If the rvalue is the result of a function call it will be
6573 a TARGET_EXPR. If it is some other construct (such as a
6574 member access expression where the underlying object is
6575 itself the result of a function call), turn it into a
6576 TARGET_EXPR here. It is important that EXPR be a
6577 TARGET_EXPR below since otherwise the INIT_EXPR will
6578 attempt to make a bitwise copy of EXPR to initialize
6579 VAR. */
6582 /* Create the INIT_EXPR that will initialize the temporary
6583 variable. */
6586 {
6590 /* We must be careful to destroy the temporary only
6591 after its initialization has taken place. If the
6592 initialization throws an exception, then the
6593 destructor should not be run. We cannot simply
6594 transform INIT into something like:
6596 (INIT, ({ CLEANUP_STMT; }))
6598 because emit_local_var always treats the
6599 initializer as a full-expression. Thus, the
6600 destructor would run too early; it would run at the
6601 end of initializing the reference variable, rather
6602 than at the end of the block enclosing the
6603 reference variable.
6605 The solution is to pass back a cleanup expression
6606 which the caller is responsible for attaching to
6607 the statement tree. */
6608 }
6609 else
6610 {
6614 static_aggregates);
6615 }
6616 /* Use its address to initialize the reference variable. */
6624 }
6625 else
6626 /* Take the address of EXPR. */
6628 /* If a BASE_CONV was required, perform it now. */
6630 expr = (perform_implicit_conversion
6633 }
6634 }
6635 else
6636 /* Perform the conversion. */
6639 /* Free all the conversions we allocated. */
6643 }