| blob | b83ad3a2eef41270954378bd4e533ee340238746 |
1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
4 Free Software Foundation, Inc.
5 Contributed by Michael Tiemann (tiemann@cygnus.com) and
6 modified by Brendan Kehoe (brendan@cygnus.com).
8 This file is part of GCC.
10 GCC is free software; you can redistribute it and/or modify
11 it under the terms of the GNU General Public License as published by
12 the Free Software Foundation; either version 3, or (at your option)
13 any later version.
15 GCC is distributed in the hope that it will be useful,
16 but WITHOUT ANY WARRANTY; without even the implied warranty of
17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 GNU General Public License for more details.
20 You should have received a copy of the GNU General Public License
21 along with GCC; see the file COPYING3. If not see
22 <http://www.gnu.org/licenses/>. */
25 /* High-level class interface. */
44 /* The various kinds of conversion. */
47 ck_identity,
48 ck_lvalue,
49 ck_qual,
50 ck_std,
51 ck_ptr,
52 ck_pmem,
53 ck_base,
54 ck_ref_bind,
55 ck_user,
56 ck_ambig,
57 ck_rvalue
60 /* The rank of the conversion. Order of the enumerals matters; better
61 conversions should come earlier in the list. */
64 cr_identity,
65 cr_exact,
66 cr_promotion,
67 cr_std,
68 cr_pbool,
69 cr_user,
70 cr_ellipsis,
71 cr_bad
74 /* An implicit conversion sequence, in the sense of [over.best.ics].
75 The first conversion to be performed is at the end of the chain.
76 That conversion is always a cr_identity conversion. */
80 /* The kind of conversion represented by this step. */
81 conversion_kind kind;
82 /* The rank of this conversion. */
83 conversion_rank rank;
88 /* If KIND is ck_ref_bind ck_base_conv, true to indicate that a
89 temporary should be created to hold the result of the
90 conversion. */
92 /* If KIND is ck_ptr or ck_pmem, true to indicate that a conversion
93 from a pointer-to-derived to pointer-to-base is being performed. */
95 /* If KIND is ck_ref_bind, true when either an lvalue reference is
96 being bound to an lvalue expression or an rvalue reference is
97 being bound to an rvalue expression. */
99 /* The type of the expression resulting from the conversion. */
100 tree type;
102 /* The next conversion in the chain. Since the conversions are
103 arranged from outermost to innermost, the NEXT conversion will
104 actually be performed before this conversion. This variant is
105 used only when KIND is neither ck_identity nor ck_ambig. */
107 /* The expression at the beginning of the conversion chain. This
108 variant is used only if KIND is ck_identity or ck_ambig. */
109 tree expr;
111 /* The function candidate corresponding to this conversion
112 sequence. This field is only used if KIND is ck_user. */
114 };
116 #define CONVERSION_RANK(NODE) \
117 ((NODE)->bad_p ? cr_bad \
118 : (NODE)->ellipsis_p ? cr_ellipsis \
119 : (NODE)->user_conv_p ? cr_user \
120 : (NODE)->rank)
131 #define convert_like(CONV, EXPR, COMPLAIN) \
132 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
135 #define convert_like_with_context(CONV, EXPR, FN, ARGNO, COMPLAIN ) \
136 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
159 static void add_builtin_candidates
162 static void add_builtin_candidate
166 static void build_builtin_candidate
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 {
222 else
224 }
225 else
226 {
227 /* In the case of:
229 template <class T> struct S { ~S(); };
230 int i;
231 i.~S();
233 NAME will be a class template. */
236 }
241 }
243 /* We want the address of a function or method. We avoid creating a
244 pointer-to-member function. */
246 tree
248 {
251 /* We have to do these by hand to avoid real pointer to member
252 functions. */
254 {
256 {
260 }
262 }
263 else
267 }
269 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
270 POINTER_TYPE to those. Note, pointer to member function types
271 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
272 two variants. build_call_a is the primitive taking an array of
273 arguments, while build_call_n is a wrapper that handles varargs. */
275 tree
277 {
280 else
281 {
291 }
292 }
294 tree
296 {
299 tree decl;
300 tree result_type;
301 tree fntype;
314 {
317 {
318 /* We invoke build_call directly for several library
319 functions. These may have been declared normally if
320 we're building libgcc, so we can't just check
321 DECL_ARTIFICIAL. */
326 }
327 }
328 else
331 /* We check both the decl and the type; a function may be known not to
332 throw without being declared throw(). */
346 /* Don't pass empty class objects by value. This is useful
347 for tags in STL, which are used to control overload resolution.
348 We don't need to handle other cases of copying empty classes. */
353 {
357 }
364 }
366 /* Build something of the form ptr->method (args)
367 or object.method (args). This can also build
368 calls to constructors, and find friends.
370 Member functions always take their class variable
371 as a pointer.
373 INSTANCE is a class instance.
375 NAME is the name of the method desired, usually an IDENTIFIER_NODE.
377 PARMS help to figure out what that NAME really refers to.
379 BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
380 down to the real instance type to use for access checking. We need this
381 information to get protected accesses correct.
383 FLAGS is the logical disjunction of zero or more LOOKUP_
384 flags. See cp-tree.h for more info.
386 If this is all OK, calls build_function_call with the resolved
387 member function.
389 This function must also handle being called to perform
390 initialization, promotion/coercion of arguments, and
391 instantiation of default parameters.
393 Note that NAME may refer to an instance variable name. If
394 `operator()()' is defined for the type of that field, then we return
395 that result. */
397 /* New overloading code. */
405 };
408 /* The FUNCTION_DECL that will be called if this candidate is
409 selected by overload resolution. */
410 tree fn;
411 /* The arguments to use when calling this function. */
412 tree args;
413 /* The implicit conversion sequences for each of the arguments to
414 FN. */
416 /* The number of implicit conversion sequences. */
418 /* If FN is a user-defined conversion, the standard conversion
419 sequence from the type returned by FN to the desired destination
420 type. */
423 /* If FN is a member function, the binfo indicating the path used to
424 qualify the name of FN at the call site. This path is used to
425 determine whether or not FN is accessible if it is selected by
426 overload resolution. The DECL_CONTEXT of FN will always be a
427 (possibly improper) base of this binfo. */
428 tree access_path;
429 /* If FN is a non-static member function, the binfo indicating the
430 subobject to which the `this' pointer should be converted if FN
431 is selected by overload resolution. The type pointed to the by
432 the `this' pointer must correspond to the most derived class
433 indicated by the CONVERSION_PATH. */
434 tree conversion_path;
435 tree template_decl;
438 };
440 /* Returns true iff T is a null pointer constant in the sense of
441 [conv.ptr]. */
443 bool
445 {
446 /* [conv.ptr]
448 A null pointer constant is an integral constant expression
449 (_expr.const_) rvalue of integer type that evaluates to zero. */
454 {
458 }
460 }
462 /* Returns nonzero if PARMLIST consists of only default parms and/or
463 ellipsis. */
465 bool
467 {
473 }
475 /* Allocate N bytes of memory from the conversion obstack. The memory
476 is zeroed before being returned. */
480 {
483 {
486 }
490 }
492 /* Dynamically allocate a conversion. */
496 {
501 }
503 #ifdef ENABLE_CHECKING
505 /* Make sure that all memory on the conversion obstack has been
506 freed. */
508 void
510 {
514 }
518 /* Dynamically allocate an array of N conversions. */
522 {
524 }
528 {
532 /* We can't use buildl1 here because CODE could be USER_CONV, which
533 takes two arguments. In that case, the caller is responsible for
534 filling in the second argument. */
540 {
556 }
562 }
564 /* Build a representation of the identity conversion from EXPR to
565 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
569 {
577 }
579 /* Converting from EXPR to TYPE was ambiguous in the sense that there
580 were multiple user-defined conversions to accomplish the job.
581 Build a conversion that indicates that ambiguity. */
585 {
593 }
595 tree
597 {
601 }
603 /* Returns the standard conversion path (see [conv]) from type FROM to type
604 TO, if any. For proper handling of null pointer constants, you must
605 also pass the expression EXPR to convert from. If C_CAST_P is true,
606 this conversion is coming from a C-style cast. */
611 {
618 {
621 }
627 {
632 }
639 {
643 }
645 {
647 {
648 tree bitfield_type;
651 {
654 }
655 }
657 }
659 /* Allow conversion between `__complex__' data types. */
661 {
662 /* The standard conversion sequence to convert FROM to TO is
663 the standard conversion sequence to perform componentwise
664 conversion. */
669 {
672 }
673 else
677 }
687 {
688 /* For backwards brain damage compatibility, allow interconversion of
689 pointers and integers with a pedwarn. */
692 }
694 {
695 /* For backwards brain damage compatibility, allow interconversion of
696 enums and integers with a pedwarn. */
699 }
702 {
703 tree to_pointee;
704 tree from_pointee;
709 ;
713 {
714 from = build_pointer_type
718 }
720 {
725 && (same_type_ignoring_top_level_qualifiers_p
728 {
732 }
735 }
738 /* [conv.ptr]
740 An rvalue of type "pointer to cv D," where D is a
741 class type, can be converted to an rvalue of type
742 "pointer to cv B," where B is a base class (clause
743 _class.derived_) of D. If B is an inaccessible
744 (clause _class.access_) or ambiguous
745 (_class.member.lookup_) base class of D, a program
746 that necessitates this conversion is ill-formed.
747 Therefore, we use DERIVED_FROM_P, and do not check
748 access or uniqueness. */
750 {
751 from =
757 }
760 {
763 }
764 else
765 {
768 }
773 /* In a C-style cast, we ignore CV-qualification because we
774 are allowed to perform a static_cast followed by a
775 const_cast. */
780 /* converting from string constant to char *. */
783 {
786 }
787 else
791 }
793 {
813 }
815 {
816 /* [conv.bool]
818 An rvalue of arithmetic, enumeration, pointer, or pointer to
819 member type can be converted to an rvalue of type bool. */
824 {
832 }
835 }
836 /* We don't check for ENUMERAL_TYPE here because there are no standard
837 conversions to enum type. */
838 /* As an extension, allow conversion to complex type. */
840 {
845 /* Give this a better rank if it's a promotion. */
849 }
855 {
859 /* The derived-to-base conversion indicates the initialization
860 of a parameter with base type from an object of a derived
861 type. A temporary object is created to hold the result of
862 the conversion unless we're binding directly to a reference. */
864 }
865 else
869 }
871 /* Returns nonzero if T1 is reference-related to T2. */
873 static bool
875 {
879 /* [dcl.init.ref]
881 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
882 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
883 of T2. */
887 }
889 /* Returns nonzero if T1 is reference-compatible with T2. */
891 static bool
893 {
894 /* [dcl.init.ref]
896 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
897 reference-related to T2 and cv1 is the same cv-qualification as,
898 or greater cv-qualification than, cv2. */
901 }
903 /* Determine whether or not the EXPR (of class type S) can be
904 converted to T as in [over.match.ref]. */
908 {
909 tree conversions;
910 tree arglist;
912 tree t;
921 /* [over.match.ref]
923 Assuming that "cv1 T" is the underlying type of the reference
924 being initialized, and "cv S" is the type of the initializer
925 expression, with S a class type, the candidate functions are
926 selected as follows:
928 --The conversion functions of S and its base classes are
929 considered. Those that are not hidden within S and yield type
930 "reference to cv2 T2", where "cv1 T" is reference-compatible
931 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
933 The argument list has one argument, which is the initializer
934 expression. */
938 /* Conceptually, we should take the address of EXPR and put it in
939 the argument list. Unfortunately, however, that can result in
940 error messages, which we should not issue now because we are just
941 trying to find a conversion operator. Therefore, we use NULL,
942 cast to the appropriate type. */
949 {
953 {
959 /* If this is a template function, try to get an exact
960 match. */
962 {
965 NULL_TREE,
966 arglist,
967 reference_type,
970 LOOKUP_NORMAL,
971 DEDUCE_CONV);
974 {
975 /* Now, see if the conversion function really returns
976 an lvalue of the appropriate type. From the
977 point of view of unification, simply returning an
978 rvalue of the right type is good enough. */
983 {
986 }
987 }
988 }
994 LOOKUP_NORMAL);
997 {
999 /* Build a standard conversion sequence indicating the
1000 binding from the reference type returned by the
1001 function to the desired REFERENCE_TYPE. */
1002 identity_conv
1005 NULL_TREE);
1006 cand->second_conv
1007 = (direct_reference_binding
1013 }
1014 }
1016 }
1019 /* If none of the conversion functions worked out, let our caller
1020 know. */
1028 /* Now that we know that this is the function we're going to use fix
1029 the dummy first argument. */
1034 /* Build a user-defined conversion sequence representing the
1035 conversion. */
1041 /* Merge it with the standard conversion sequence from the
1042 conversion function's return type to the desired type. */
1049 }
1051 /* A reference of the indicated TYPE is being bound directly to the
1052 expression represented by the implicit conversion sequence CONV.
1053 Return a conversion sequence for this binding. */
1057 {
1058 tree t;
1065 /* [over.ics.rank]
1067 When a parameter of reference type binds directly
1068 (_dcl.init.ref_) to an argument expression, the implicit
1069 conversion sequence is the identity conversion, unless the
1070 argument expression has a type that is a derived class of the
1071 parameter type, in which case the implicit conversion sequence is
1072 a derived-to-base Conversion.
1074 If the parameter binds directly to the result of applying a
1075 conversion function to the argument expression, the implicit
1076 conversion sequence is a user-defined conversion sequence
1077 (_over.ics.user_), with the second standard conversion sequence
1078 either an identity conversion or, if the conversion function
1079 returns an entity of a type that is a derived class of the
1080 parameter type, a derived-to-base conversion. */
1082 {
1083 /* Represent the derived-to-base conversion. */
1085 /* We will actually be binding to the base-class subobject in
1086 the derived class, so we mark this conversion appropriately.
1087 That way, convert_like knows not to generate a temporary. */
1089 }
1091 }
1093 /* Returns the conversion path from type FROM to reference type TO for
1094 purposes of reference binding. For lvalue binding, either pass a
1095 reference type to FROM or an lvalue expression to EXPR. If the
1096 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1097 the conversion returned. If C_CAST_P is true, this
1098 conversion is coming from a C-style cast. */
1102 {
1106 tree tfrom;
1112 {
1117 }
1120 {
1121 /* Anything with reference type is an lvalue. */
1124 }
1132 /* Figure out whether or not the types are reference-related and
1133 reference compatible. We have do do this after stripping
1134 references from FROM. */
1136 /* If this is a C cast, first convert to an appropriately qualified
1137 type, so that we can later do a const_cast to the desired type. */
1143 /* Directly bind reference when target expression's type is compatible with
1144 the reference and expression is an lvalue. In DR391, the wording in
1145 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1146 const and rvalue references to rvalues of compatible class type. */
1148 && (lvalue_p
1152 {
1153 /* [dcl.init.ref]
1155 If the initializer expression
1157 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1158 is reference-compatible with "cv2 T2,"
1160 the reference is bound directly to the initializer expression
1161 lvalue.
1163 [...]
1164 If the initializer expression is an rvalue, with T2 a class type,
1165 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1166 is bound to the object represented by the rvalue or to a sub-object
1167 within that object. */
1173 /* The top-level caller requested that we pretend that the lvalue
1174 be treated as an rvalue. */
1176 else
1177 conv->rvaluedness_matches_p
1182 /* For the purposes of overload resolution, we ignore the fact
1183 this expression is a bitfield or packed field. (In particular,
1184 [over.ics.ref] says specifically that a function with a
1185 non-const reference parameter is viable even if the
1186 argument is a bitfield.)
1188 However, when we actually call the function we must create
1189 a temporary to which to bind the reference. If the
1190 reference is volatile, or isn't const, then we cannot make
1191 a temporary, so we just issue an error when the conversion
1192 actually occurs. */
1196 }
1197 /* [class.conv.fct] A conversion function is never used to convert a
1198 (possibly cv-qualified) object to the (possibly cv-qualified) same
1199 object type (or a reference to it), to a (possibly cv-qualified) base
1200 class of that type (or a reference to it).... */
1203 {
1204 /* [dcl.init.ref]
1206 If the initializer expression
1208 -- has a class type (i.e., T2 is a class type) can be
1209 implicitly converted to an lvalue of type "cv3 T3," where
1210 "cv1 T1" is reference-compatible with "cv3 T3". (this
1211 conversion is selected by enumerating the applicable
1212 conversion functions (_over.match.ref_) and choosing the
1213 best one through overload resolution. (_over.match_).
1215 the reference is bound to the lvalue result of the conversion
1216 in the second case. */
1220 }
1222 /* From this point on, we conceptually need temporaries, even if we
1223 elide them. Only the cases above are "direct bindings". */
1227 /* [over.ics.rank]
1229 When a parameter of reference type is not bound directly to an
1230 argument expression, the conversion sequence is the one required
1231 to convert the argument expression to the underlying type of the
1232 reference according to _over.best.ics_. Conceptually, this
1233 conversion sequence corresponds to copy-initializing a temporary
1234 of the underlying type with the argument expression. Any
1235 difference in top-level cv-qualification is subsumed by the
1236 initialization itself and does not constitute a conversion. */
1238 /* [dcl.init.ref]
1240 Otherwise, the reference shall be to a non-volatile const type.
1242 Under C++0x, [8.5.3/5 dcl.init.ref] it may also be an rvalue reference */
1246 /* [dcl.init.ref]
1248 Otherwise, a temporary of type "cv1 T1" is created and
1249 initialized from the initializer expression using the rules for a
1250 non-reference copy initialization. If T1 is reference-related to
1251 T2, cv1 must be the same cv-qualification as, or greater
1252 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1256 /* We're generating a temporary now, but don't bind any more in the
1257 conversion (specifically, don't slice the temporary returned by a
1258 conversion operator). */
1262 flags);
1267 /* This reference binding, unlike those above, requires the
1268 creation of a temporary. */
1273 }
1275 /* Returns the implicit conversion sequence (see [over.ics]) from type
1276 FROM to type TO. The optional expression EXPR may affect the
1277 conversion. FLAGS are the usual overloading flags. Only
1278 LOOKUP_NO_CONVERSION is significant. If C_CAST_P is true, this
1279 conversion is coming from a C-style cast. */
1284 {
1293 else
1303 {
1312 /* We used to try to bind a reference to a temporary here, but that
1313 is now handled after the recursive call to this function at the end
1314 of reference_binding. */
1316 }
1319 }
1321 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1322 functions. */
1330 {
1345 }
1347 /* Create an overload candidate for the function or method FN called with
1348 the argument list ARGLIST and add it to CANDIDATES. FLAGS is passed on
1349 to implicit_conversion.
1351 CTYPE, if non-NULL, is the type we want to pretend this function
1352 comes from for purposes of overload resolution. */
1359 {
1364 tree orig_arglist;
1367 /* At this point we should not see any functions which haven't been
1368 explicitly declared, except for friend functions which will have
1369 been found using argument dependent lookup. */
1372 /* The `this', `in_chrg' and VTT arguments to constructors are not
1373 considered in overload resolution. */
1375 {
1379 }
1380 else
1386 /* 13.3.2 - Viable functions [over.match.viable]
1387 First, to be a viable function, a candidate function shall have enough
1388 parameters to agree in number with the arguments in the list.
1390 We need to check this first; otherwise, checking the ICSes might cause
1391 us to produce an ill-formed template instantiation. */
1395 {
1399 }
1404 /* Make sure there are default args for the rest of the parms. */
1411 /* Second, for F to be a viable function, there shall exist for each
1412 argument an implicit conversion sequence that converts that argument
1413 to the corresponding parameter of F. */
1419 {
1432 {
1435 /* The type of the implicit object parameter ('this') for
1436 overload resolution is not always the same as for the
1437 function itself; conversion functions are considered to
1438 be members of the class being converted, and functions
1439 introduced by a using-declaration are considered to be
1440 members of the class that uses them.
1442 Since build_over_call ignores the ICS for the `this'
1443 parameter, we can just change the parm type. */
1445 {
1446 parmtype
1450 }
1454 }
1455 else
1456 {
1459 }
1466 {
1469 }
1477 }
1479 out:
1482 }
1484 /* Create an overload candidate for the conversion function FN which will
1485 be invoked for expression OBJ, producing a pointer-to-function which
1486 will in turn be called with the argument list ARGLIST, and add it to
1487 CANDIDATES. FLAGS is passed on to implicit_conversion.
1489 Actually, we don't really care about FN; we care about the type it
1490 converts to. There may be multiple conversion functions that will
1491 convert to that type, and we rely on build_user_type_conversion_1 to
1492 choose the best one; so when we create our candidate, we record the type
1493 instead of the function. */
1498 {
1515 /* Don't bother looking up the same type twice. */
1520 {
1527 flags);
1533 else
1534 {
1537 }
1552 }
1562 }
1564 static void
1568 {
1582 {
1589 {
1591 /* We need something for printing the candidate. */
1593 }
1597 }
1599 /* For COND_EXPR we rearranged the arguments; undo that now. */
1601 {
1608 else
1610 }
1616 viable);
1617 }
1619 static bool
1621 {
1623 }
1625 /* Returns nonzero if TYPE is a promoted arithmetic type. */
1627 static bool
1629 {
1630 /* [over.built]
1632 In this section, the term promoted integral type is used to refer
1633 to those integral types which are preserved by integral promotion
1634 (including e.g. int and long but excluding e.g. char).
1635 Similarly, the term promoted arithmetic type refers to promoted
1636 integral types plus floating types. */
1640 }
1642 /* Create any builtin operator overload candidates for the operator in
1643 question given the converted operand types TYPE1 and TYPE2. The other
1644 args are passed through from add_builtin_candidates to
1645 build_builtin_candidate.
1647 TYPE1 and TYPE2 may not be permissible, and we must filter them.
1648 If CODE is requires candidates operands of the same type of the kind
1649 of which TYPE1 and TYPE2 are, we add both candidates
1650 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
1652 static void
1656 {
1658 {
1666 }
1669 {
1671 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
1672 and VQ is either volatile or empty, there exist candidate operator
1673 functions of the form
1674 VQ T& operator++(VQ T&);
1675 T operator++(VQ T&, int);
1676 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
1677 type other than bool, and VQ is either volatile or empty, there exist
1678 candidate operator functions of the form
1679 VQ T& operator--(VQ T&);
1680 T operator--(VQ T&, int);
1681 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
1682 complete object type, and VQ is either volatile or empty, there exist
1683 candidate operator functions of the form
1684 T*VQ& operator++(T*VQ&);
1685 T*VQ& operator--(T*VQ&);
1686 T* operator++(T*VQ&, int);
1687 T* operator--(T*VQ&, int); */
1696 {
1699 }
1702 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
1703 exist candidate operator functions of the form
1705 T& operator*(T*);
1707 8 For every function type T, there exist candidate operator functions of
1708 the form
1709 T& operator*(T*); */
1718 /* 9 For every type T, there exist candidate operator functions of the form
1719 T* operator+(T*);
1721 10For every promoted arithmetic type T, there exist candidate operator
1722 functions of the form
1723 T operator+(T);
1724 T operator-(T); */
1734 /* 11For every promoted integral type T, there exist candidate operator
1735 functions of the form
1736 T operator~(T); */
1743 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
1744 is the same type as C2 or is a derived class of C2, T is a complete
1745 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
1746 there exist candidate operator functions of the form
1747 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
1748 where CV12 is the union of CV1 and CV2. */
1753 {
1761 }
1764 /* 13For every pair of promoted arithmetic types L and R, there exist can-
1765 didate operator functions of the form
1766 LR operator*(L, R);
1767 LR operator/(L, R);
1768 LR operator+(L, R);
1769 LR operator-(L, R);
1770 bool operator<(L, R);
1771 bool operator>(L, R);
1772 bool operator<=(L, R);
1773 bool operator>=(L, R);
1774 bool operator==(L, R);
1775 bool operator!=(L, R);
1776 where LR is the result of the usual arithmetic conversions between
1777 types L and R.
1779 14For every pair of types T and I, where T is a cv-qualified or cv-
1780 unqualified complete object type and I is a promoted integral type,
1781 there exist candidate operator functions of the form
1782 T* operator+(T*, I);
1783 T& operator[](T*, I);
1784 T* operator-(T*, I);
1785 T* operator+(I, T*);
1786 T& operator[](I, T*);
1788 15For every T, where T is a pointer to complete object type, there exist
1789 candidate operator functions of the form112)
1790 ptrdiff_t operator-(T, T);
1792 16For every pointer or enumeration type T, there exist candidate operator
1793 functions of the form
1794 bool operator<(T, T);
1795 bool operator>(T, T);
1796 bool operator<=(T, T);
1797 bool operator>=(T, T);
1798 bool operator==(T, T);
1799 bool operator!=(T, T);
1801 17For every pointer to member type T, there exist candidate operator
1802 functions of the form
1803 bool operator==(T, T);
1804 bool operator!=(T, T); */
1810 {
1813 }
1826 {
1829 }
1831 {
1834 }
1835 /* Fall through. */
1852 {
1855 }
1859 {
1862 }
1870 {
1873 }
1875 {
1878 }
1881 /* 18For every pair of promoted integral types L and R, there exist candi-
1882 date operator functions of the form
1883 LR operator%(L, R);
1884 LR operator&(L, R);
1885 LR operator^(L, R);
1886 LR operator|(L, R);
1887 L operator<<(L, R);
1888 L operator>>(L, R);
1889 where LR is the result of the usual arithmetic conversions between
1890 types L and R. */
1902 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
1903 type, VQ is either volatile or empty, and R is a promoted arithmetic
1904 type, there exist candidate operator functions of the form
1905 VQ L& operator=(VQ L&, R);
1906 VQ L& operator*=(VQ L&, R);
1907 VQ L& operator/=(VQ L&, R);
1908 VQ L& operator+=(VQ L&, R);
1909 VQ L& operator-=(VQ L&, R);
1911 20For every pair T, VQ), where T is any type and VQ is either volatile
1912 or empty, there exist candidate operator functions of the form
1913 T*VQ& operator=(T*VQ&, T*);
1915 21For every pair T, VQ), where T is a pointer to member type and VQ is
1916 either volatile or empty, there exist candidate operator functions of
1917 the form
1918 VQ T& operator=(VQ T&, T);
1920 22For every triple T, VQ, I), where T is a cv-qualified or cv-
1921 unqualified complete object type, VQ is either volatile or empty, and
1922 I is a promoted integral type, there exist candidate operator func-
1923 tions of the form
1924 T*VQ& operator+=(T*VQ&, I);
1925 T*VQ& operator-=(T*VQ&, I);
1927 23For every triple L, VQ, R), where L is an integral or enumeration
1928 type, VQ is either volatile or empty, and R is a promoted integral
1929 type, there exist candidate operator functions of the form
1931 VQ L& operator%=(VQ L&, R);
1932 VQ L& operator<<=(VQ L&, R);
1933 VQ L& operator>>=(VQ L&, R);
1934 VQ L& operator&=(VQ L&, R);
1935 VQ L& operator^=(VQ L&, R);
1936 VQ L& operator|=(VQ L&, R); */
1940 {
1944 {
1947 }
1973 {
1976 }
1981 }
1986 /* [over.built]
1988 For every pair of promoted arithmetic types L and R, there
1989 exist candidate operator functions of the form
1991 LR operator?(bool, L, R);
1993 where LR is the result of the usual arithmetic conversions
1994 between types L and R.
1996 For every type T, where T is a pointer or pointer-to-member
1997 type, there exist candidate operator functions of the form T
1998 operator?(bool, T, T); */
2002 /* That's OK. */
2005 /* Otherwise, the types should be pointers. */
2010 /* We don't check that the two types are the same; the logic
2011 below will actually create two candidates; one in which both
2012 parameter types are TYPE1, and one in which both parameter
2013 types are TYPE2. */
2018 }
2020 /* If we're dealing with two pointer types or two enumeral types,
2021 we need candidates for both of them. */
2030 {
2031 build_builtin_candidate
2033 build_builtin_candidate
2036 }
2038 build_builtin_candidate
2040 }
2042 tree
2044 {
2050 }
2052 /* There are three conditions of builtin candidates:
2054 1) bool-taking candidates. These are the same regardless of the input.
2055 2) pointer-pair taking candidates. These are generated for each type
2056 one of the input types converts to.
2057 3) arithmetic candidates. According to the standard, we should generate
2058 all of these, but I'm trying not to...
2060 Here we generate a superset of the possible candidates for this particular
2061 case. That is a subset of the full set the standard defines, plus some
2062 other cases which the standard disallows. add_builtin_candidate will
2063 filter out the invalid set. */
2065 static void
2069 {
2073 /* TYPES[i] is the set of possible builtin-operator parameter types
2074 we will consider for the Ith argument. These are represented as
2075 a TREE_LIST; the TREE_VALUE of each node is the potential
2076 parameter type. */
2080 {
2083 else
2085 }
2088 {
2089 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2090 and VQ is either volatile or empty, there exist candidate operator
2091 functions of the form
2092 VQ T& operator++(VQ T&); */
2102 /* 24There also exist candidate operator functions of the form
2103 bool operator!(bool);
2104 bool operator&&(bool, bool);
2105 bool operator||(bool, bool); */
2108 build_builtin_candidate
2115 build_builtin_candidate
2133 /* Fall through. */
2137 }
2142 {
2144 ;
2146 {
2147 tree convs;
2155 {
2162 }
2168 {
2181 {
2187 }
2191 }
2192 }
2193 else
2194 {
2200 {
2206 }
2208 }
2209 }
2211 /* Run through the possible parameter types of both arguments,
2212 creating candidates with those parameter types. */
2214 {
2217 add_builtin_candidate
2220 else
2221 add_builtin_candidate
2224 }
2225 }
2228 /* If TMPL can be successfully instantiated as indicated by
2229 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2231 TMPL is the template. EXPLICIT_TARGS are any explicit template
2232 arguments. ARGLIST is the arguments provided at the call-site.
2233 The RETURN_TYPE is the desired type for conversion operators. If
2234 OBJ is NULL_TREE, FLAGS and CTYPE are as for add_function_candidate.
2235 If an OBJ is supplied, FLAGS and CTYPE are ignored, and OBJ is as for
2236 add_conv_candidate. */
2243 unification_kind_t strict)
2244 {
2250 tree fn;
2252 /* We don't do deduction on the in-charge parameter, the VTT
2253 parameter or 'this'. */
2263 args_without_in_chrg,
2273 /* In [class.copy]:
2275 A member function template is never instantiated to perform the
2276 copy of a class object to an object of its class type.
2278 It's a little unclear what this means; the standard explicitly
2279 does allow a template to be used to copy a class. For example,
2280 in:
2282 struct A {
2283 A(A&);
2284 template <class T> A(const T&);
2285 };
2286 const A f ();
2287 void g () { A a (f ()); }
2289 the member template will be used to make the copy. The section
2290 quoted above appears in the paragraph that forbids constructors
2291 whose only parameter is (a possibly cv-qualified variant of) the
2292 class type, and a logical interpretation is that the intent was
2293 to forbid the instantiation of member templates which would then
2294 have that form. */
2296 {
2299 ctype))
2301 }
2304 /* Aha, this is a conversion function. */
2307 else
2312 /* This situation can occur if a member template of a template
2313 class is specialized. Then, instantiate_template might return
2314 an instantiation of the specialization, in which case the
2315 DECL_TI_TEMPLATE field will point at the original
2316 specialization. For example:
2318 template <class T> struct S { template <class U> void f(U);
2319 template <> void f(int) {}; };
2320 S<double> sd;
2321 sd.f(3);
2323 Here, TMPL will be template <class U> S<double>::f(U).
2324 And, instantiate template will give us the specialization
2325 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2326 for this will point at template <class T> template <> S<T>::f(int),
2327 so that we can find the definition. For the purposes of
2328 overload resolution, however, we want the original TMPL. */
2330 else
2334 }
2341 unification_kind_t strict)
2342 {
2343 return
2348 }
2355 {
2356 return
2360 }
2362 /* The CANDS are the set of candidates that were considered for
2363 overload resolution. Return the set of viable candidates. If none
2364 of the candidates were viable, set *ANY_VIABLE_P to true. STRICT_P
2365 is true if a candidate should be considered viable only if it is
2366 strictly viable. */
2372 {
2383 {
2386 {
2392 }
2393 else
2395 }
2398 }
2400 static bool
2402 {
2407 }
2409 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2410 words, it is about to become the "this" pointer for a member
2411 function call. Take the address of the object. */
2413 static tree
2415 {
2416 /* In a template, we are only concerned about the type of the
2417 expression, so we can take a shortcut. */
2422 }
2424 /* Returns true iff functions are equivalent. Equivalent functions are
2425 not '==' only if one is a function-local extern function or if
2426 both are extern "C". */
2430 {
2435 }
2437 /* Print information about one overload candidate CANDIDATE. MSGSTR
2438 is the text to print before the candidate itself.
2440 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2441 to have been run through gettext by the caller. This wart makes
2442 life simpler in print_z_candidates and for the translators. */
2444 static void
2446 {
2448 {
2458 else
2461 }
2466 else
2468 }
2470 static void
2472 {
2477 /* There may be duplicates in the set of candidates. We put off
2478 checking this condition as long as possible, since we have no way
2479 to eliminate duplicates from a set of functions in less than n^2
2480 time. Now we are about to emit an error message, so it is more
2481 permissible to go slowly. */
2483 {
2485 /* Skip builtin candidates and conversion functions. */
2490 {
2494 else
2496 }
2497 }
2505 {
2506 /* Indent successive candidates by the width of the translation
2507 of the above string. */
2514 do
2515 {
2518 }
2520 }
2521 }
2523 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2524 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2525 the result of the conversion function to convert it to the final
2526 desired type. Merge the two sequences into a single sequence,
2527 and return the merged sequence. */
2531 {
2536 /* Find the end of the second conversion sequence. */
2541 /* Replace the identity conversion with the user conversion
2542 sequence. */
2545 /* The entire sequence is a user-conversion sequence. */
2549 }
2551 /* Returns the best overload candidate to perform the requested
2552 conversion. This function is used for three the overloading situations
2553 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2554 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2555 per [dcl.init.ref], so we ignore temporary bindings. */
2559 {
2569 /* We represent conversion within a hierarchy using RVALUE_CONV and
2570 BASE_CONV, as specified by [over.best.ics]; these become plain
2571 constructor calls, as specified in [dcl.init]. */
2579 {
2584 {
2585 /* [class.conv.fct] A conversion function is never used to
2586 convert a (possibly cv-qualified) object to the (possibly
2587 cv-qualified) same object type (or a reference to it), to a
2588 (possibly cv-qualified) base class of that type (or a
2589 reference to it)... */
2590 }
2591 else
2593 }
2598 /* It's OK to bind a temporary for converting constructor arguments, but
2599 not in converting the return value of a conversion operator. */
2604 {
2605 tree t;
2611 /* We should never try to call the abstract or base constructor
2612 from here. */
2616 }
2618 {
2628 flags,
2629 DEDUCE_CALL);
2630 else
2634 flags);
2637 {
2640 /* If totype isn't a reference, and LOOKUP_NO_TEMP_BIND isn't
2641 set, then this is copy-initialization. In that case, "The
2642 result of the call is then used to direct-initialize the
2643 object that is the destination of the copy-initialization."
2644 [dcl.init]
2646 We represent this in the conversion sequence with an
2647 rvalue conversion, which means a constructor call. */
2650 cand->second_conv
2652 }
2653 }
2659 {
2660 tree fns;
2663 /* If we are called to convert to a reference type, we are trying to
2664 find an lvalue binding, so don't even consider temporaries. If
2665 we don't find an lvalue binding, the caller will try again to
2666 look for a temporary binding. */
2671 {
2674 /* [over.match.funcs] For conversion functions, the function
2675 is considered to be a member of the class of the implicit
2676 object argument for the purpose of defining the type of
2677 the implicit object parameter.
2679 So we pass fromtype as CTYPE to add_*_candidate. */
2683 NULL_TREE,
2686 conversion_path,
2687 flags,
2688 DEDUCE_CONV);
2689 else
2691 args,
2693 conversion_path,
2694 flags);
2697 {
2698 conversion *ics
2704 /* If LOOKUP_NO_TEMP_BIND isn't set, then this is
2705 copy-initialization. In that case, "The result of the
2706 call is then used to direct-initialize the object that is
2707 the destination of the copy-initialization." [dcl.init]
2709 We represent this in the conversion sequence with an
2710 rvalue conversion, which means a constructor call. But
2711 don't add a second rvalue conversion if there's already
2712 one there. Which there really shouldn't be, but it's
2713 harmless since we'd add it here anyway. */
2724 }
2725 }
2726 }
2734 {
2736 {
2740 }
2747 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
2748 ambiguous conversion is no worse than another user-defined
2749 conversion. */
2752 }
2754 /* Build the user conversion sequence. */
2755 conv = build_conv
2762 /* Combine it with the second conversion sequence. */
2770 }
2772 tree
2774 {
2779 {
2784 }
2786 }
2788 /* Do any initial processing on the arguments to a function call. */
2790 static tree
2792 {
2793 tree t;
2795 {
2801 {
2804 }
2807 }
2809 }
2811 /* Perform overload resolution on FN, which is called with the ARGS.
2813 Return the candidate function selected by overload resolution, or
2814 NULL if the event that overload resolution failed. In the case
2815 that overload resolution fails, *CANDIDATES will be the set of
2816 candidates considered, and ANY_VIABLE_P will be set to true or
2817 false to indicate whether or not any of the candidates were
2818 viable.
2820 The ARGS should already have gone through RESOLVE_ARGS before this
2821 function is called. */
2825 tree args,
2828 {
2836 /* Check FN and ARGS. */
2844 {
2848 }
2850 /* Add the various candidate functions. */
2854 LOOKUP_NORMAL,
2855 candidates);
2863 }
2865 /* Return an expression for a call to FN (a namespace-scope function,
2866 or a static member function) with the ARGS. */
2868 tree
2870 tsubst_flags_t complain)
2871 {
2875 tree result;
2881 /* If this function was found without using argument dependent
2882 lookup, then we want to ignore any undeclared friend
2883 functions. */
2885 {
2890 {
2895 }
2896 }
2898 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2904 {
2906 {
2914 else
2919 }
2921 }
2922 else
2925 /* Free all the conversions we allocated. */
2929 }
2931 /* Build a call to a global operator new. FNNAME is the name of the
2932 operator (either "operator new" or "operator new[]") and ARGS are
2933 the arguments provided. *SIZE points to the total number of bytes
2934 required by the allocation, and is updated if that is changed here.
2935 *COOKIE_SIZE is non-NULL if a cookie should be used. If this
2936 function determines that no cookie should be used, after all,
2937 *COOKIE_SIZE is set to NULL_TREE. If FN is non-NULL, it will be
2938 set, upon return, to the allocation function called. */
2940 tree
2944 {
2945 tree fns;
2957 /* Based on:
2959 [expr.new]
2961 If this lookup fails to find the name, or if the allocated type
2962 is not a class type, the allocation function's name is looked
2963 up in the global scope.
2965 we disregard block-scope declarations of "operator new". */
2968 /* Figure out what function is being called. */
2971 /* If no suitable function could be found, issue an error message
2972 and give up. */
2974 {
2978 else
2984 }
2986 /* If a cookie is required, add some extra space. Whether
2987 or not a cookie is required cannot be determined until
2988 after we know which function was called. */
2990 {
2993 {
2995 /* In G++ 3.2, the check was implemented incorrectly; it
2996 looked at the placement expression, rather than the
2997 type of the function. */
3000 ptr_type_node))
3002 }
3003 else
3004 {
3005 tree arg_types;
3008 /* Skip the size_t parameter. */
3010 /* Check the remaining parameters (if any). */
3014 ptr_type_node))
3016 }
3017 /* If we need a cookie, adjust the number of bytes allocated. */
3019 {
3020 /* Update the total size. */
3022 /* Update the argument list to reflect the adjusted size. */
3024 }
3025 else
3027 }
3029 /* Tell our caller which function we decided to call. */
3033 /* Build the CALL_EXPR. */
3035 }
3037 static tree
3039 {
3048 {
3050 /* It's no good looking for an overloaded operator() on a
3051 pointer-to-member-function. */
3052 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
3054 }
3057 {
3061 }
3062 else
3070 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3074 {
3079 {
3087 else
3088 add_function_candidate
3091 }
3092 }
3097 {
3109 {
3112 add_template_conv_candidate
3116 else
3120 }
3121 }
3125 {
3127 {
3130 }
3132 }
3133 else
3134 {
3137 {
3139 {
3143 }
3145 }
3146 /* Since cand->fn will be a type, not a function, for a conversion
3147 function, we must be careful not to unconditionally look at
3148 DECL_NAME here. */
3152 else
3153 {
3155 complain);
3158 }
3159 }
3161 /* Free all the conversions we allocated. */
3165 }
3167 static void
3170 {
3175 else
3179 {
3203 else
3207 }
3208 }
3210 /* Return the implicit conversion sequence that could be used to
3211 convert E1 to E2 in [expr.cond]. */
3215 {
3221 /* [expr.cond]
3223 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3224 implicitly converted (clause _conv_) to the type "reference to
3225 T2", subject to the constraint that in the conversion the
3226 reference must bind directly (_dcl.init.ref_) to E1. */
3228 {
3230 t1,
3231 e1,
3233 LOOKUP_NO_TEMP_BIND);
3236 }
3238 /* [expr.cond]
3240 If E1 and E2 have class type, and the underlying class types are
3241 the same or one is a base class of the other: E1 can be converted
3242 to match E2 if the class of T2 is the same type as, or a base
3243 class of, the class of T1, and the cv-qualification of T2 is the
3244 same cv-qualification as, or a greater cv-qualification than, the
3245 cv-qualification of T1. If the conversion is applied, E1 is
3246 changed to an rvalue of type T2 that still refers to the original
3247 source class object (or the appropriate subobject thereof). */
3250 {
3252 {
3257 else
3260 }
3261 else
3263 }
3264 else
3265 /* [expr.cond]
3267 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3268 converted to the type that expression E2 would have if E2 were
3269 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3271 LOOKUP_NORMAL);
3272 }
3274 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3275 arguments to the conditional expression. */
3277 tree
3279 tsubst_flags_t complain)
3280 {
3281 tree arg2_type;
3282 tree arg3_type;
3290 /* As a G++ extension, the second argument to the conditional can be
3291 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3292 c'.) If the second operand is omitted, make sure it is
3293 calculated only once. */
3295 {
3299 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3302 else
3304 }
3306 /* [expr.cond]
3308 The first expr ession is implicitly converted to bool (clause
3309 _conv_). */
3312 /* If something has already gone wrong, just pass that fact up the
3313 tree. */
3319 /* [expr.cond]
3321 If either the second or the third operand has type (possibly
3322 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3323 array-to-pointer (_conv.array_), and function-to-pointer
3324 (_conv.func_) standard conversions are performed on the second
3325 and third operands. */
3329 {
3330 /* Do the conversions. We don't these for `void' type arguments
3331 since it can't have any effect and since decay_conversion
3332 does not handle that case gracefully. */
3340 /* [expr.cond]
3342 One of the following shall hold:
3344 --The second or the third operand (but not both) is a
3345 throw-expression (_except.throw_); the result is of the
3346 type of the other and is an rvalue.
3348 --Both the second and the third operands have type void; the
3349 result is of type void and is an rvalue.
3351 We must avoid calling force_rvalue for expressions of type
3352 "void" because it will complain that their value is being
3353 used. */
3356 {
3361 }
3364 {
3369 }
3372 else
3373 {
3375 {
3378 "is of type %<void%>, "
3379 "but the third operand is neither a throw-expression "
3381 else
3383 "is of type %<void%>, "
3384 "but the second operand is neither a throw-expression "
3386 }
3388 }
3392 }
3393 /* [expr.cond]
3395 Otherwise, if the second and third operand have different types,
3396 and either has (possibly cv-qualified) class type, an attempt is
3397 made to convert each of those operands to the type of the other. */
3400 {
3404 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3410 /* [expr.cond]
3412 If both can be converted, or one can be converted but the
3413 conversion is ambiguous, the program is ill-formed. If
3414 neither can be converted, the operands are left unchanged and
3415 further checking is performed as described below. If exactly
3416 one conversion is possible, that conversion is applied to the
3417 chosen operand and the converted operand is used in place of
3418 the original operand for the remainder of this section. */
3423 {
3427 }
3429 {
3433 /* Even if CONV2 is a valid conversion, the result of the
3434 conversion may be invalid. For example, if ARG3 has type
3435 "volatile X", and X does not have a copy constructor
3436 accepting a "volatile X&", then even if ARG2 can be
3437 converted to X, the conversion will fail. */
3440 }
3442 {
3448 }
3450 /* Free all the conversions we allocated. */
3456 /* If, after the conversion, both operands have class type,
3457 treat the cv-qualification of both operands as if it were the
3458 union of the cv-qualification of the operands.
3460 The standard is not clear about what to do in this
3461 circumstance. For example, if the first operand has type
3462 "const X" and the second operand has a user-defined
3463 conversion to "volatile X", what is the type of the second
3464 operand after this step? Making it be "const X" (matching
3465 the first operand) seems wrong, as that discards the
3466 qualification without actually performing a copy. Leaving it
3467 as "volatile X" seems wrong as that will result in the
3468 conditional expression failing altogether, even though,
3469 according to this step, the one operand could be converted to
3470 the type of the other. */
3478 }
3480 /* [expr.cond]
3482 If the second and third operands are lvalues and have the same
3483 type, the result is of that type and is an lvalue. */
3487 {
3490 }
3492 /* [expr.cond]
3494 Otherwise, the result is an rvalue. If the second and third
3495 operand do not have the same type, and either has (possibly
3496 cv-qualified) class type, overload resolution is used to
3497 determine the conversions (if any) to be applied to the operands
3498 (_over.match.oper_, _over.built_). */
3502 {
3507 /* Rearrange the arguments so that add_builtin_candidate only has
3508 to know about two args. In build_builtin_candidates, the
3509 arguments are unscrambled. */
3514 COND_EXPR,
3515 NOP_EXPR,
3517 args,
3518 LOOKUP_NORMAL);
3520 /* [expr.cond]
3522 If the overload resolution fails, the program is
3523 ill-formed. */
3526 {
3528 {
3531 }
3533 }
3536 {
3538 {
3541 }
3543 }
3545 /* [expr.cond]
3547 Otherwise, the conversions thus determined are applied, and
3548 the converted operands are used in place of the original
3549 operands for the remainder of this section. */
3556 }
3558 /* [expr.cond]
3560 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3561 and function-to-pointer (_conv.func_) standard conversions are
3562 performed on the second and third operands.
3564 We need to force the lvalue-to-rvalue conversion here for class types,
3565 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3566 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3567 regions. */
3580 /* [expr.cond]
3582 After those conversions, one of the following shall hold:
3584 --The second and third operands have the same type; the result is of
3585 that type. */
3588 /* [expr.cond]
3590 --The second and third operands have arithmetic or enumeration
3591 type; the usual arithmetic conversions are performed to bring
3592 them to a common type, and the result is of that type. */
3597 {
3598 /* In this case, there is always a common type. */
3600 arg3_type);
3604 {
3609 }
3615 {
3619 }
3623 }
3624 /* [expr.cond]
3626 --The second and third operands have pointer type, or one has
3627 pointer type and the other is a null pointer constant; pointer
3628 conversions (_conv.ptr_) and qualification conversions
3629 (_conv.qual_) are performed to bring them to their composite
3630 pointer type (_expr.rel_). The result is of the composite
3631 pointer type.
3633 --The second and third operands have pointer to member type, or
3634 one has pointer to member type and the other is a null pointer
3635 constant; pointer to member conversions (_conv.mem_) and
3636 qualification conversions (_conv.qual_) are performed to bring
3637 them to a common type, whose cv-qualification shall match the
3638 cv-qualification of either the second or the third operand.
3639 The result is of the common type. */
3647 {
3650 complain);
3655 }
3658 {
3663 }
3665 valid_operands:
3668 /* We can't use result_type below, as fold might have returned a
3669 throw_expr. */
3672 {
3673 /* Expand both sides into the same slot, hopefully the target of
3674 the ?: expression. We used to check for TARGET_EXPRs here,
3675 but now we sometimes wrap them in NOP_EXPRs so the test would
3676 fail. */
3679 /* If this expression is an rvalue, but might be mistaken for an
3680 lvalue, we must add a NON_LVALUE_EXPR. */
3682 }
3685 }
3687 /* OPERAND is an operand to an expression. Perform necessary steps
3688 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
3689 returned. */
3691 static tree
3693 {
3695 {
3698 /* Make sure the template type is instantiated now. */
3700 }
3703 }
3705 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
3706 OVERLOAD) to the CANDIDATES, returning an updated list of
3707 CANDIDATES. The ARGS are the arguments provided to the call,
3708 without any implicit object parameter. The EXPLICIT_TARGS are
3709 explicit template arguments provided. TEMPLATE_ONLY is true if
3710 only template functions should be considered. CONVERSION_PATH,
3711 ACCESS_PATH, and FLAGS are as for add_function_candidate. */
3713 static void
3719 {
3720 tree ctype;
3721 tree non_static_args;
3724 /* Delay creating the implicit this parameter until it is needed. */
3728 {
3729 tree fn;
3730 tree fn_args;
3733 /* Figure out which set of arguments to use. */
3735 {
3736 /* If this function is a non-static member, prepend the implicit
3737 object parameter. */
3743 }
3744 else
3745 /* Otherwise, just use the list of arguments provided. */
3750 fn,
3751 ctype,
3752 explicit_targs,
3753 fn_args,
3754 NULL_TREE,
3755 access_path,
3756 conversion_path,
3757 flags,
3758 DEDUCE_CALL);
3761 fn,
3762 ctype,
3763 fn_args,
3764 access_path,
3765 conversion_path,
3766 flags);
3768 }
3769 }
3771 tree
3774 {
3793 {
3797 }
3798 else
3804 {
3809 /* Use build_op_new_call and build_op_delete_call instead. */
3823 }
3829 {
3836 }
3851 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3854 /* Add namespace-scope operators to the list of functions to
3855 consider. */
3859 /* Add class-member operators to the candidate set. */
3861 {
3862 tree fns;
3866 {
3869 }
3876 }
3878 /* Rearrange the arguments for ?: so that add_builtin_candidate only has
3879 to know about two args; a builtin candidate will always have a first
3880 parameter of type bool. We'll handle that in
3881 build_builtin_candidate. */
3883 {
3887 }
3888 else
3889 {
3893 }
3898 {
3901 /* For these, the built-in candidates set is empty
3902 [over.match.oper]/3. We don't want non-strict matches
3903 because exact matches are always possible with built-in
3904 operators. The built-in candidate set for COMPONENT_REF
3905 would be empty too, but since there are no such built-in
3906 operators, we accept non-strict matches for them. */
3913 }
3917 {
3919 {
3922 /* Don't try anything fancy if we're not allowed to produce
3923 errors. */
3927 /* Look for an `operator++ (int)'. If they didn't have
3928 one, then we fall back to the old way of doing things. */
3932 fnname,
3936 else
3942 /* The caller will deal with these. */
3952 {
3955 }
3958 }
3959 }
3960 else
3961 {
3964 {
3966 {
3969 }
3971 }
3973 {
3979 else
3981 }
3982 else
3983 {
3984 /* Give any warnings we noticed during overload resolution. */
3986 {
3990 }
3992 /* Check for comparison of different enum types. */
3994 {
4006 {
4009 }
4013 }
4015 /* We need to strip any leading REF_BIND so that bitfields
4016 don't cause errors. This should not remove any important
4017 conversions, because builtins don't apply to class
4018 objects directly. */
4024 {
4029 }
4031 {
4036 }
4039 {
4043 }
4044 }
4045 }
4047 user_defined_result_ready:
4049 /* Free all the conversions we allocated. */
4055 builtin:
4057 {
4110 complain),
4111 arg2);
4113 /* The caller will deal with these. */
4121 }
4123 }
4125 /* Build a call to operator delete. This has to be handled very specially,
4126 because the restrictions on what signatures match are different from all
4127 other call instances. For a normal delete, only a delete taking (void *)
4128 or (void *, size_t) is accepted. For a placement delete, only an exact
4129 match with the placement new is accepted.
4131 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
4132 ADDR is the pointer to be deleted.
4133 SIZE is the size of the memory block to be deleted.
4134 GLOBAL_P is true if the delete-expression should not consider
4135 class-specific delete operators.
4136 PLACEMENT is the corresponding placement new call, or NULL_TREE.
4138 If this call to "operator delete" is being generated as part to
4139 deallocate memory allocated via a new-expression (as per [expr.new]
4140 which requires that if the initialization throws an exception then
4141 we call a deallocation function), then ALLOC_FN is the allocation
4142 function. */
4144 tree
4147 tree alloc_fn)
4148 {
4163 /* In [class.free]
4165 If the result of the lookup is ambiguous or inaccessible, or if
4166 the lookup selects a placement deallocation function, the
4167 program is ill-formed.
4169 Therefore, we ask lookup_fnfields to complain about ambiguity. */
4170 {
4174 }
4175 else
4181 /* Strip const and volatile from addr. */
4185 {
4186 /* Get the parameter types for the allocation function that is
4187 being called. */
4190 }
4191 else
4192 {
4193 /* First try it without the size argument. */
4195 }
4197 /* We make two tries at finding a matching `operator delete'. On
4198 the first pass, we look for a one-operator (or placement)
4199 operator delete. If we're not doing placement delete, then on
4200 the second pass we look for a two-argument delete. */
4202 {
4203 /* Go through the `operator delete' functions looking for one
4204 with a matching type. */
4206 fn;
4208 {
4209 tree t;
4211 /* The first argument must be "void *". */
4216 /* On the first pass, check the rest of the arguments. */
4218 {
4221 {
4226 }
4229 }
4230 /* On the second pass, look for a function with exactly two
4231 arguments: "void *" and "size_t". */
4233 /* For "operator delete(void *, ...)" there will be
4234 no second argument, but we will not get an exact
4235 match above. */
4236 && t
4240 }
4242 /* If we found a match, we're done. */
4245 }
4247 /* If we have a matching function, call it. */
4249 {
4250 /* Make sure we have the actual function, and not an
4251 OVERLOAD. */
4254 /* If the FN is a member function, make sure that it is
4255 accessible. */
4260 {
4261 /* The placement args might not be suitable for overload
4262 resolution at this point, so build the call directly. */
4271 }
4272 else
4273 {
4274 tree args;
4277 else
4281 }
4282 }
4284 /* [expr.new]
4286 If no unambiguous matching deallocation function can be found,
4287 propagating the exception does not cause the object's memory to
4288 be freed. */
4290 {
4293 alloc_fn);
4295 }
4300 }
4302 /* If the current scope isn't allowed to access DECL along
4303 BASETYPE_PATH, give an error. The most derived class in
4304 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
4305 the declaration to use in the error diagnostic. */
4307 bool
4309 {
4313 {
4318 else
4322 }
4325 }
4327 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
4328 bitwise or of LOOKUP_* values. If any errors are warnings are
4329 generated, set *DIAGNOSTIC_FN to "error" or "warning",
4330 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
4331 to NULL. */
4333 static tree
4336 {
4341 complete_ctor_identifier,
4348 else
4351 }
4353 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
4354 EXPR is implicitly converted to type TOTYPE.
4355 FN and ARGNUM are used for diagnostics. */
4357 static void
4359 {
4362 /* Issue warnings about peculiar, but valid, uses of NULL. */
4364 {
4368 else
4370 }
4372 /* Issue warnings if "false" is converted to a NULL pointer */
4377 }
4379 /* Perform the conversions in CONVS on the expression EXPR. FN and
4380 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4381 indicates the `this' argument of a method. INNER is nonzero when
4382 being called to continue a conversion chain. It is negative when a
4383 reference binding will be applied, positive otherwise. If
4384 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
4385 conversions will be emitted if appropriate. If C_CAST_P is true,
4386 this conversion is coming from a C-style cast; in that case,
4387 conversions to inaccessible bases are permitted. */
4389 static tree
4393 {
4395 diagnostic_fn_t diagnostic_fn;
4402 {
4405 {
4407 {
4411 complain);
4413 }
4418 complain);
4421 }
4423 {
4427 }
4428 else
4432 }
4438 {
4440 {
4445 /* Set user_conv_p on the argument conversions, so rvalue/base
4446 handling knows not to allow any more UDCs. */
4452 /* If this is a constructor or a function returning an aggr type,
4453 we need to build up a TARGET_EXPR. */
4458 }
4462 /* Convert a constant to its underlying value, unless we are
4463 about to bind it to a reference, in which case we need to
4464 leave it as an lvalue. */
4466 {
4469 /* If __null has been converted to an integer type, we do not
4470 want to warn about uses of EXPR as an integer, rather than
4471 as a pointer. */
4473 }
4476 /* Call build_user_type_conversion again for the error. */
4477 return build_user_type_conversion
4482 };
4487 c_cast_p,
4488 complain);
4493 {
4498 /* Else fall through. */
4501 {
4502 /* We are going to bind a reference directly to a base-class
4503 subobject of EXPR. */
4504 /* Build an expression for `*((base*) &expr)'. */
4510 }
4512 /* Copy-initialization where the cv-unqualified version of the source
4513 type is the same class as, or a derived class of, the class of the
4514 destination [is treated as direct-initialization]. [dcl.init] */
4517 /* This conversion is being done in the context of a user-defined
4518 conversion (i.e. the second step of copy-initialization), so
4519 don't allow any more. */
4523 {
4528 }
4532 {
4535 /* If necessary, create a temporary.
4537 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
4538 that need temporaries, even when their types are reference
4539 compatible with the type of reference being bound, so the
4540 upcoming call to cp_build_unary_op (ADDR_EXPR, expr, ...)
4541 doesn't fail. */
4545 {
4551 {
4553 {
4554 /* If the reference is volatile or non-const, we
4555 cannot create a temporary. */
4562 else
4564 }
4566 }
4567 /* If the source is a packed field, and we must use a copy
4568 constructor, then building the target expr will require
4569 binding the field to the reference parameter to the
4570 copy constructor, and we'll end up with an infinite
4571 loop. If we can use a bitwise copy, then we'll be
4572 OK. */
4576 {
4581 }
4585 }
4587 /* Take the address of the thing to which we will bind the
4588 reference. */
4593 /* Convert it to a pointer to the type referred to by the
4594 reference. This will adjust the pointer if a derived to
4595 base conversion is being performed. */
4597 expr);
4598 /* Convert the pointer to the desired reference type. */
4600 }
4606 /* Warn about deprecated conversion if appropriate. */
4618 c_cast_p);
4622 }
4626 else
4630 }
4632 /* Build a call to __builtin_trap. */
4634 static tree
4636 {
4642 }
4644 /* ARG is being passed to a varargs function. Perform any conversions
4645 required. Return the converted value. */
4647 tree
4649 {
4650 /* [expr.call]
4652 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
4653 standard conversions are performed. */
4655 /* [expr.call]
4657 If the argument has integral or enumeration type that is subject
4658 to the integral promotions (_conv.prom_), or a floating point
4659 type that is subject to the floating point promotion
4660 (_conv.fpprom_), the value of the argument is converted to the
4661 promoted type before the call. */
4673 {
4674 /* Undefined behavior [expr.call] 5.2.2/7. We used to just warn
4675 here and do a bitwise copy, but now cp_expr_size will abort if we
4676 try to do that.
4677 If the call appears in the context of a sizeof expression,
4678 there is no need to emit a warning, since the expression won't be
4679 evaluated. We keep the builtin_trap just as a safety check. */
4685 integer_zero_node);
4686 }
4689 }
4691 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
4693 tree
4695 {
4705 {
4706 /* Remove reference types so we don't ICE later on. */
4708 /* Undefined behavior [expr.call] 5.2.2/7. */
4716 }
4719 }
4721 /* TYPE has been given to va_arg. Apply the default conversions which
4722 would have happened when passed via ellipsis. Return the promoted
4723 type, or the passed type if there is no change. */
4725 tree
4727 {
4728 tree promote;
4730 /* Perform the array-to-pointer and function-to-pointer
4731 conversions. */
4739 }
4741 /* ARG is a default argument expression being passed to a parameter of
4742 the indicated TYPE, which is a parameter to FN. Do any required
4743 conversions. Return the converted value. */
4747 tree
4749 {
4751 tree t;
4753 /* If the ARG is an unparsed default argument expression, the
4754 conversion cannot be performed. */
4756 {
4761 }
4763 /* Detect recursion. */
4766 {
4769 }
4778 {
4782 tf_warning_or_error);
4783 }
4784 else
4785 {
4786 /* We must make a copy of ARG, in case subsequent processing
4787 alters any part of it. For example, during gimplification a
4788 cast of the form (T) &X::f (where "f" is a member function)
4789 will lead to replacing the PTRMEM_CST for &X::f with a
4790 VAR_DECL. We can avoid the copy for constants, since they
4791 are never modified in place. */
4796 tf_warning_or_error);
4798 }
4803 }
4805 /* Returns the type which will really be used for passing an argument of
4806 type TYPE. */
4808 tree
4810 {
4811 /* Pass classes with copy ctors by invisible reference. */
4813 {
4815 /* There are no other pointers to this temporary. */
4817 }
4826 }
4828 /* Actually perform the appropriate conversion. */
4830 tree
4832 {
4833 tree bitfield_type;
4835 /* If VAL is a bitfield, then -- since it has already been converted
4836 to TYPE -- it cannot have a precision greater than TYPE.
4838 If it has a smaller precision, we must widen it here. For
4839 example, passing "int f:3;" to a function expecting an "int" will
4840 not result in any conversion before this point.
4842 If the precision is the same we must not risk widening. For
4843 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
4844 often have type "int", even though the C++ type for the field is
4845 "long long". If the value is being passed to a function
4846 expecting an "int", then no conversions will be required. But,
4847 if we call convert_bitfield_to_declared_type, the bitfield will
4848 be converted to "long long". */
4855 ;
4856 /* Pass classes with copy ctors by invisible reference. */
4866 {
4875 }
4877 }
4879 /* Returns true iff FN is a function with magic varargs, i.e. ones for
4880 which no conversions at all should be done. This is true for some
4881 builtins which don't act like normal functions. */
4883 static bool
4885 {
4888 {
4898 }
4901 }
4903 /* Subroutine of the various build_*_call functions. Overload resolution
4904 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
4905 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
4906 bitmask of various LOOKUP_* flags which apply to the call itself. */
4908 static tree
4910 {
4924 /* In a template, there is no need to perform all of the work that
4925 is normally done. We are only interested in the type of the call
4926 expression, i.e., the return type of the function. Any semantic
4927 errors will be deferred until the template is instantiated. */
4929 {
4930 tree expr;
4931 tree return_type;
4939 }
4941 /* Give any warnings we noticed during overload resolution. */
4943 {
4947 }
4950 {
4951 /* If FN is a template function, two cases must be considered.
4952 For example:
4954 struct A {
4955 protected:
4956 template <class T> void f();
4957 };
4958 template <class T> struct B {
4959 protected:
4960 void g();
4961 };
4962 struct C : A, B<int> {
4963 using A::f; // #1
4964 using B<int>::g; // #2
4965 };
4967 In case #1 where `A::f' is a member template, DECL_ACCESS is
4968 recorded in the primary template but not in its specialization.
4969 We check access of FN using its primary template.
4971 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
4972 because it is a member of class template B, DECL_ACCESS is
4973 recorded in the specialization `B<int>::g'. We cannot use its
4974 primary template because `B<T>::g' and `B<int>::g' may have
4975 different access. */
4980 else
4982 }
4988 /* Find maximum size of vector to hold converted arguments. */
4995 /* The implicit parameters to a constructor are not considered by overload
4996 resolution, and must be of the proper type. */
4998 {
5002 /* We should never try to call the abstract constructor. */
5006 {
5010 }
5011 }
5012 /* Bypass access control for 'this' parameter. */
5014 {
5017 tree converted_arg;
5018 tree base_binfo;
5021 {
5025 else
5027 }
5029 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
5030 X is called for an object that is not of type X, or of a type
5031 derived from X, the behavior is undefined.
5033 So we can assume that anything passed as 'this' is non-null, and
5034 optimize accordingly. */
5036 /* Convert to the base in which the function was declared. */
5042 /* Check that the base class is accessible. */
5048 /* If fn was found by a using declaration, the conversion path
5049 will be to the derived class, not the base declaring fn. We
5050 must convert from derived to base. */
5061 }
5065 {
5070 /* Don't make a copy here if build_call is going to. */
5076 val = convert_like_with_context
5082 else
5084 }
5086 /* Default arguments */
5091 /* Ellipsis */
5093 {
5097 else
5100 }
5108 /* Avoid actually calling copy constructors and copy assignment operators,
5109 if possible. */
5116 {
5117 tree targ;
5120 /* Pull out the real argument, disregarding const-correctness. */
5126 {
5131 }
5132 else
5137 else
5140 /* [class.copy]: the copy constructor is implicitly defined even if
5141 the implementation elided its use. */
5145 /* If we're creating a temp and we already have one, don't create a
5146 new one. If we're not creating a temp but we get one, use
5147 INIT_EXPR to collapse the temp into our target. Otherwise, if the
5148 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
5149 temp or an INIT_EXPR otherwise. */
5151 {
5156 }
5160 {
5161 tree to = stabilize_reference
5166 }
5167 }
5171 {
5172 tree to = stabilize_reference
5179 {
5182 }
5183 else
5184 {
5185 /* We must only copy the non-tail padding parts.
5186 Use __builtin_memcpy for the bitwise copy. */
5198 }
5201 }
5206 {
5207 tree t;
5213 /* Warn about deprecated virtual functions now, since we're about
5214 to throw away the decl. */
5224 else
5227 }
5230 else
5234 }
5236 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
5237 This function performs no overload resolution, conversion, or other
5238 high-level operations. */
5240 tree
5242 {
5243 tree fndecl;
5247 /* If this call might throw an exception, note that fact. */
5254 /* Some built-in function calls will be evaluated at compile-time in
5255 fold (). */
5268 }
5272 /* Make an expression which yields the address of the Java interface
5273 method FN. This is achieved by generating a call to libjava's
5274 _Jv_LookupInterfaceMethodIdx(). */
5276 static tree
5278 {
5284 {
5289 endlink)));
5290 java_iface_lookup_fn
5294 }
5296 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
5297 This is the first entry in the vtable. */
5299 tf_warning_or_error),
5300 integer_zero_node);
5302 /* Get the java.lang.Class pointer for the interface being called. */
5307 {
5309 iface);
5311 }
5315 /* Determine the itable index of FN. */
5318 {
5323 i++;
5324 }
5329 java_iface_lookup_fn);
5332 }
5334 /* Returns the value to use for the in-charge parameter when making a
5335 call to a function with the indicated NAME.
5337 FIXME:Can't we find a neater way to do this mapping? */
5339 tree
5341 {
5352 /* This function should only be called with one of the names listed
5353 above. */
5356 }
5358 /* Build a call to a constructor, destructor, or an assignment
5359 operator for INSTANCE, an expression with class type. NAME
5360 indicates the special member function to call; ARGS are the
5361 arguments. BINFO indicates the base of INSTANCE that is to be
5362 passed as the `this' parameter to the member function called.
5364 FLAGS are the LOOKUP_* flags to use when processing the call.
5366 If NAME indicates a complete object constructor, INSTANCE may be
5367 NULL_TREE. In this case, the caller will call build_cplus_new to
5368 store the newly constructed object into a VAR_DECL. */
5370 tree
5373 {
5374 tree fns;
5375 /* The type of the subobject to be constructed or destroyed. */
5376 tree class_type;
5385 {
5386 /* Resolve the name. */
5391 }
5397 /* Handle the special case where INSTANCE is NULL_TREE. */
5399 {
5402 }
5403 else
5404 {
5410 /* Convert to the base class, if necessary. */
5413 {
5415 /* For constructors and destructors, either the base is
5416 non-virtual, or it is virtual but we are doing the
5417 conversion from a constructor or destructor for the
5418 complete object. In either case, we can convert
5419 statically. */
5421 else
5422 /* However, for assignment operators, we must convert
5423 dynamically if the base is virtual. */
5426 }
5427 }
5433 /* When making a call to a constructor or destructor for a subobject
5434 that uses virtual base classes, pass down a pointer to a VTT for
5435 the subobject. */
5439 {
5440 tree vtt;
5441 tree sub_vtt;
5443 /* If the current function is a complete object constructor
5444 or destructor, then we fetch the VTT directly.
5445 Otherwise, we look it up using the VTT we were given. */
5451 current_vtt_parm,
5452 vtt);
5458 }
5463 complain);
5464 }
5466 /* Return the NAME, as a C string. The NAME indicates a function that
5467 is a member of TYPE. *FREE_P is set to true if the caller must
5468 free the memory returned.
5470 Rather than go through all of this, we should simply set the names
5471 of constructors and destructors appropriately, and dispense with
5472 ctor_identifier, dtor_identifier, etc. */
5476 {
5479 /* Assume that we will not allocate memory. */
5481 /* Constructors and destructors are special. */
5483 {
5484 pretty_name
5486 /* For a destructor, add the '~'. */
5490 {
5492 /* Remember that we need to free the memory allocated. */
5494 }
5495 }
5497 {
5500 TFF_PLAIN_IDENTIFIER),
5501 NULL);
5502 /* Remember that we need to free the memory allocated. */
5504 }
5505 else
5509 }
5511 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
5512 be set, upon return, to the function called. */
5514 tree
5518 {
5522 tree access_binfo;
5523 tree optype;
5525 tree name;
5526 tree user_args;
5527 tree call;
5528 tree fn;
5529 tree class_type;
5532 tree orig_instance;
5533 tree orig_fns;
5534 tree orig_args;
5539 /* We don't know what function we're going to call, yet. */
5549 {
5553 }
5559 /* Dismantle the baselink to collect all the information we need. */
5566 {
5570 }
5581 {
5584 }
5586 /* The USER_ARGS are the arguments we will display to users if an
5587 error occurs. The USER_ARGS should not include any
5588 compiler-generated arguments. The "this" pointer hasn't been
5589 added yet. However, we must remove the VTT pointer if this is a
5590 call to a base-class constructor or destructor. */
5593 {
5594 /* Callers should explicitly indicate whether they want to construct
5595 the complete object or just the part without virtual bases. */
5597 /* Similarly for destructors. */
5599 /* Remove the VTT pointer, if present. */
5603 }
5605 /* Process the argument list. */
5612 /* It's OK to call destructors and constructors on cv-qualified objects.
5613 Therefore, convert the INSTANCE_PTR to the unqualified type, if
5614 necessary. */
5617 {
5621 }
5628 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5632 {
5634 tree this_arglist;
5636 /* We can end up here for copy-init of same or base class. */
5643 else
5647 /* A member template. */
5649 class_type,
5650 explicit_targs,
5652 access_binfo,
5653 conversion_path,
5654 flags,
5655 DEDUCE_CALL);
5658 class_type,
5659 this_arglist,
5660 access_binfo,
5661 conversion_path,
5662 flags);
5663 }
5667 {
5669 {
5672 else
5673 {
5683 }
5685 }
5687 }
5688 else
5689 {
5692 {
5697 {
5700 user_args);
5704 }
5706 }
5707 else
5708 {
5717 /* This is not an error, it is runtime undefined
5718 behavior. */
5720 "abstract virtual %q#D called from constructor"
5722 fn);
5726 {
5729 fn);
5731 }
5732 else
5733 {
5737 /* Now we know what function is being called. */
5740 /* Build the actual CALL_EXPR. */
5742 /* In an expression of the form `a->f()' where `f' turns
5743 out to be a static member function, `a' is
5744 none-the-less evaluated. */
5753 /* An explicit call of the form "x->~X()" has type
5754 "void". However, on platforms where destructors
5755 return "this" (i.e., those where
5756 targetm.cxx.cdtor_returns_this is true), such calls
5757 will appear to have a return value of pointer type
5758 to the low-level call machinery. We do not want to
5759 change the low-level machinery, since we want to be
5760 able to optimize "delete f()" on such platforms as
5761 "operator delete(~X(f()))" (rather than generating
5762 "t = f(), ~X(t), operator delete (t)"). */
5764 }
5765 }
5766 }
5769 call = (build_min_non_dep_call_list
5772 orig_args));
5774 /* Free all the conversions we allocated. */
5778 }
5780 /* Returns true iff standard conversion sequence ICS1 is a proper
5781 subsequence of ICS2. */
5783 static bool
5785 {
5786 /* We can assume that a conversion of the same code
5787 between the same types indicates a subsequence since we only get
5788 here if the types we are converting from are the same. */
5795 {
5803 /* At this point, ICS1 cannot be a proper subsequence of
5804 ICS2. We can get a USER_CONV when we are comparing the
5805 second standard conversion sequence of two user conversion
5806 sequences. */
5816 }
5817 }
5819 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
5820 be any _TYPE nodes. */
5822 bool
5824 {
5828 /* We only allow proper derivation here. The DERIVED_FROM_P macro
5829 considers every class derived from itself. */
5832 }
5834 /* We build the ICS for an implicit object parameter as a pointer
5835 conversion sequence. However, such a sequence should be compared
5836 as if it were a reference conversion sequence. If ICS is the
5837 implicit conversion sequence for an implicit object parameter,
5838 modify it accordingly. */
5840 static void
5842 {
5844 {
5845 /* [over.match.funcs]
5847 For non-static member functions, the type of the
5848 implicit object parameter is "reference to cv X"
5849 where X is the class of which the function is a
5850 member and cv is the cv-qualification on the member
5851 function declaration. */
5853 tree reference_type;
5855 /* The `this' parameter is a pointer to a class type. Make the
5856 implicit conversion talk about a reference to that same class
5857 type. */
5870 }
5871 }
5873 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
5874 and return the initial reference binding conversion. Otherwise,
5875 leave *ICS unchanged and return NULL. */
5879 {
5881 {
5887 }
5890 }
5892 /* Compare two implicit conversion sequences according to the rules set out in
5893 [over.ics.rank]. Return values:
5895 1: ics1 is better than ics2
5896 -1: ics2 is better than ics1
5897 0: ics1 and ics2 are indistinguishable */
5899 static int
5901 {
5902 tree from_type1;
5903 tree from_type2;
5904 tree to_type1;
5905 tree to_type2;
5912 /* REF_BINDING is nonzero if the result of the conversion sequence
5913 is a reference type. In that case REF_CONV is the reference
5914 binding conversion. */
5918 /* Handle implicit object parameters. */
5922 /* Handle reference parameters. */
5926 /* [over.ics.rank]
5928 When comparing the basic forms of implicit conversion sequences (as
5929 defined in _over.best.ics_)
5931 --a standard conversion sequence (_over.ics.scs_) is a better
5932 conversion sequence than a user-defined conversion sequence
5933 or an ellipsis conversion sequence, and
5935 --a user-defined conversion sequence (_over.ics.user_) is a
5936 better conversion sequence than an ellipsis conversion sequence
5937 (_over.ics.ellipsis_). */
5947 {
5948 /* XXX Isn't this an extension? */
5949 /* Both ICS are bad. We try to make a decision based on what
5950 would have happened if they'd been good. */
5958 /* We couldn't make up our minds; try to figure it out below. */
5959 }
5962 /* Both conversions are ellipsis conversions. */
5965 /* User-defined conversion sequence U1 is a better conversion sequence
5966 than another user-defined conversion sequence U2 if they contain the
5967 same user-defined conversion operator or constructor and if the sec-
5968 ond standard conversion sequence of U1 is better than the second
5969 standard conversion sequence of U2. */
5972 {
5986 /* We can just fall through here, after setting up
5987 FROM_TYPE1 and FROM_TYPE2. */
5990 }
5991 else
5992 {
5996 /* We're dealing with two standard conversion sequences.
5998 [over.ics.rank]
6000 Standard conversion sequence S1 is a better conversion
6001 sequence than standard conversion sequence S2 if
6003 --S1 is a proper subsequence of S2 (comparing the conversion
6004 sequences in the canonical form defined by _over.ics.scs_,
6005 excluding any Lvalue Transformation; the identity
6006 conversion sequence is considered to be a subsequence of
6007 any non-identity conversion sequence */
6018 }
6020 /* One sequence can only be a subsequence of the other if they start with
6021 the same type. They can start with different types when comparing the
6022 second standard conversion sequence in two user-defined conversion
6023 sequences. */
6025 {
6030 }
6032 /* [over.ics.rank]
6034 Or, if not that,
6036 --the rank of S1 is better than the rank of S2 (by the rules
6037 defined below):
6039 Standard conversion sequences are ordered by their ranks: an Exact
6040 Match is a better conversion than a Promotion, which is a better
6041 conversion than a Conversion.
6043 Two conversion sequences with the same rank are indistinguishable
6044 unless one of the following rules applies:
6046 --A conversion that is not a conversion of a pointer, or pointer
6047 to member, to bool is better than another conversion that is such
6048 a conversion.
6050 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
6051 so that we do not have to check it explicitly. */
6060 /* A conversion from scalar arithmetic type to complex is worse than a
6061 conversion between scalar arithmetic types. */
6068 {
6071 else
6073 }
6079 {
6084 }
6085 /* The rules for pointers to members A::* are just like the rules
6086 for pointers A*, except opposite: if B is derived from A then
6087 A::* converts to B::*, not vice versa. For that reason, we
6088 switch the from_ and to_ variables here. */
6095 {
6100 }
6105 {
6106 /* This was one of the pointer or pointer-like conversions.
6108 [over.ics.rank]
6110 --If class B is derived directly or indirectly from class A,
6111 conversion of B* to A* is better than conversion of B* to
6112 void*, and conversion of A* to void* is better than
6113 conversion of B* to void*. */
6116 {
6118 deref_from_type2))
6121 deref_from_type1))
6123 }
6126 {
6128 {
6130 {
6132 deref_to_type1))
6134 }
6135 /* We know that DEREF_TO_TYPE1 is `void' here. */
6137 deref_to_type2))
6139 }
6140 }
6143 {
6144 /* [over.ics.rank]
6146 --If class B is derived directly or indirectly from class A
6147 and class C is derived directly or indirectly from B,
6149 --conversion of C* to B* is better than conversion of C* to
6150 A*,
6152 --conversion of B* to A* is better than conversion of C* to
6153 A* */
6155 {
6157 deref_to_type2))
6160 deref_to_type1))
6162 }
6164 {
6166 deref_from_type1))
6169 deref_from_type2))
6171 }
6172 }
6173 }
6176 {
6179 /* [over.ics.rank]
6181 --binding of an expression of type C to a reference of type
6182 B& is better than binding an expression of type C to a
6183 reference of type A&
6185 --conversion of C to B is better than conversion of C to A, */
6188 {
6193 }
6194 }
6197 {
6200 /* [over.ics.rank]
6202 --binding of an expression of type B to a reference of type
6203 A& is better than binding an expression of type C to a
6204 reference of type A&,
6206 --conversion of B to A is better than conversion of C to A */
6209 {
6214 }
6215 }
6217 /* [over.ics.rank]
6219 --S1 and S2 differ only in their qualification conversion and yield
6220 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
6221 qualification signature of type T1 is a proper subset of the cv-
6222 qualification signature of type T2 */
6226 {
6230 }
6232 /* [over.ics.rank]
6234 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
6235 to an implicit object parameter, and either S1 binds an lvalue reference
6236 to an lvalue and S2 binds an rvalue reference or S1 binds an rvalue
6237 reference to an rvalue and S2 binds an lvalue reference
6238 (C++0x draft standard, 13.3.3.2)
6240 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
6241 types to which the references refer are the same type except for
6242 top-level cv-qualifiers, and the type to which the reference
6243 initialized by S2 refers is more cv-qualified than the type to
6244 which the reference initialized by S1 refers */
6247 {
6251 {
6256 }
6261 }
6263 /* Neither conversion sequence is better than the other. */
6265 }
6267 /* The source type for this standard conversion sequence. */
6269 static tree
6271 {
6273 {
6278 }
6280 }
6282 /* Note a warning about preferring WINNER to LOSER. We do this by storing
6283 a pointer to LOSER and re-running joust to produce the warning if WINNER
6284 is actually used. */
6286 static void
6288 {
6294 }
6296 /* Compare two candidates for overloading as described in
6297 [over.match.best]. Return values:
6299 1: cand1 is better than cand2
6300 -1: cand2 is better than cand1
6301 0: cand1 and cand2 are indistinguishable */
6303 static int
6305 {
6311 /* Candidates that involve bad conversions are always worse than those
6312 that don't. */
6318 /* If we have two pseudo-candidates for conversions to the same type,
6319 or two candidates for the same function, arbitrarily pick one. */
6324 /* a viable function F1
6325 is defined to be a better function than another viable function F2 if
6326 for all arguments i, ICSi(F1) is not a worse conversion sequence than
6327 ICSi(F2), and then */
6329 /* for some argument j, ICSj(F1) is a better conversion sequence than
6330 ICSj(F2) */
6332 /* For comparing static and non-static member functions, we ignore
6333 the implicit object parameter of the non-static function. The
6334 standard says to pretend that the static function has an object
6335 parm, but that won't work with operator overloading. */
6338 {
6346 else
6347 {
6350 }
6351 }
6354 {
6360 {
6373 {
6380 else
6385 {
6389 }
6390 else
6392 }
6395 {
6398 }
6400 }
6401 }
6403 /* warn about confusing overload resolution for user-defined conversions,
6404 either between a constructor and a conversion op, or between two
6405 conversion ops. */
6409 {
6415 else
6418 /* We don't want to complain about `X::operator T1 ()'
6419 beating `X::operator T2 () const', when T2 is a no less
6420 cv-qualified version of T1. */
6423 {
6428 {
6431 }
6434 }
6435 else
6441 {
6449 }
6450 else
6452 }
6457 /* or, if not that,
6458 F1 is a non-template function and F2 is a template function
6459 specialization. */
6466 /* or, if not that,
6467 F1 and F2 are template functions and the function template for F1 is
6468 more specialized than the template for F2 according to the partial
6469 ordering rules. */
6472 {
6473 winner = more_specialized_fn
6476 /* [temp.func.order]: The presence of unused ellipsis and default
6477 arguments has no effect on the partial ordering of function
6478 templates. add_function_candidate() will not have
6479 counted the "this" argument for constructors. */
6483 }
6485 /* or, if not that,
6486 the context is an initialization by user-defined conversion (see
6487 _dcl.init_ and _over.match.user_) and the standard conversion
6488 sequence from the return type of F1 to the destination type (i.e.,
6489 the type of the entity being initialized) is a better conversion
6490 sequence than the standard conversion sequence from the return type
6491 of F2 to the destination type. */
6494 {
6498 }
6500 /* Check whether we can discard a builtin candidate, either because we
6501 have two identical ones or matching builtin and non-builtin candidates.
6503 (Pedantically in the latter case the builtin which matched the user
6504 function should not be added to the overload set, but we spot it here.
6506 [over.match.oper]
6507 ... the builtin candidates include ...
6508 - do not have the same parameter type list as any non-template
6509 non-member candidate. */
6513 {
6519 {
6521 /* Two built-in candidates; arbitrarily pick one. */
6524 /* cand1 is built-in; prefer cand2. */
6526 else
6527 /* cand2 is built-in; prefer cand1. */
6529 }
6530 }
6532 /* If the two functions are the same (this can happen with declarations
6533 in multiple scopes and arg-dependent lookup), arbitrarily choose one. */
6538 tweak:
6540 /* Extension: If the worst conversion for one candidate is worse than the
6541 worst conversion for the other, take the first. */
6543 {
6548 {
6553 }
6559 {
6561 {
6563 ISO C++ says that these are ambiguous, even \
6564 though the worst conversion for the first is better than \
6568 }
6569 else
6572 }
6573 }
6577 }
6579 /* Given a list of candidates for overloading, find the best one, if any.
6580 This algorithm has a worst case of O(2n) (winner is last), and a best
6581 case of O(n/2) (totally ambiguous); much better than a sorting
6582 algorithm. */
6586 {
6591 /* Walk through the list once, comparing each current champ to the next
6592 candidate, knocking out a candidate or two with each comparison. */
6595 {
6599 else
6600 {
6602 {
6607 }
6608 else
6609 {
6612 }
6615 }
6616 }
6618 /* Make sure the champ is better than all the candidates it hasn't yet
6619 been compared to. */
6622 challenger != champ
6625 {
6629 }
6632 }
6634 /* Returns nonzero if things of type FROM can be converted to TO. */
6636 bool
6638 {
6640 }
6642 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
6644 bool
6646 {
6651 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6655 flags);
6658 /* Free all the conversions we allocated. */
6662 }
6664 /* Like can_convert_arg, but allows dubious conversions as well. */
6666 bool
6668 {
6672 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6674 /* Try to perform the conversion. */
6676 LOOKUP_NORMAL);
6677 /* Free all the conversions we allocated. */
6681 }
6683 /* Convert EXPR to TYPE. Return the converted expression.
6685 Note that we allow bad conversions here because by the time we get to
6686 this point we are committed to doing the conversion. If we end up
6687 doing a bad conversion, convert_like will complain. */
6689 tree
6691 {
6698 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6703 LOOKUP_NORMAL);
6705 {
6709 }
6711 {
6712 /* In a template, we are only concerned about determining the
6713 type of non-dependent expressions, so we do not have to
6714 perform the actual conversion. */
6717 }
6718 else
6721 /* Free all the conversions we allocated. */
6725 }
6727 /* Convert EXPR to TYPE (as a direct-initialization) if that is
6728 permitted. If the conversion is valid, the converted expression is
6729 returned. Otherwise, NULL_TREE is returned, except in the case
6730 that TYPE is a class type; in that case, an error is issued. If
6731 C_CAST_P is true, then this direction initialization is taking
6732 place as part of a static_cast being attempted as part of a C-style
6733 cast. */
6735 tree
6737 tree expr,
6739 tsubst_flags_t complain)
6740 {
6746 /* [dcl.init]
6748 If the destination type is a (possibly cv-qualified) class type:
6750 -- If the initialization is direct-initialization ...,
6751 constructors are considered. ... If no constructor applies, or
6752 the overload resolution is ambiguous, the initialization is
6753 ill-formed. */
6755 {
6760 }
6762 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6766 c_cast_p,
6767 LOOKUP_NORMAL);
6770 else
6773 c_cast_p,
6774 tf_warning_or_error);
6776 /* Free all the conversions we allocated. */
6780 }
6782 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
6783 is being bound to a temporary. Create and return a new VAR_DECL
6784 with the indicated TYPE; this variable will store the value to
6785 which the reference is bound. */
6787 tree
6789 {
6790 tree var;
6792 /* Create the variable. */
6795 /* Register the variable. */
6797 {
6798 /* Namespace-scope or local static; give it a mangled name. */
6799 tree name;
6806 }
6807 else
6808 /* Create a new cleanup level if necessary. */
6812 }
6814 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
6815 initializing a variable of that TYPE. If DECL is non-NULL, it is
6816 the VAR_DECL being initialized with the EXPR. (In that case, the
6817 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
6818 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
6819 return, if *CLEANUP is no longer NULL, it will be an expression
6820 that should be pushed as a cleanup after the returned expression
6821 is used to initialize DECL.
6823 Return the converted expression. */
6825 tree
6827 {
6834 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6838 LOOKUP_NORMAL);
6840 {
6846 else
6851 }
6853 /* If DECL is non-NULL, then this special rule applies:
6855 [class.temporary]
6857 The temporary to which the reference is bound or the temporary
6858 that is the complete object to which the reference is bound
6859 persists for the lifetime of the reference.
6861 The temporaries created during the evaluation of the expression
6862 initializing the reference, except the temporary to which the
6863 reference is bound, are destroyed at the end of the
6864 full-expression in which they are created.
6866 In that case, we store the converted expression into a new
6867 VAR_DECL in a new scope.
6869 However, we want to be careful not to create temporaries when
6870 they are not required. For example, given:
6872 struct B {};
6873 struct D : public B {};
6874 D f();
6875 const B& b = f();
6877 there is no need to copy the return value from "f"; we can just
6878 extend its lifetime. Similarly, given:
6880 struct S {};
6881 struct T { operator S(); };
6882 T t;
6883 const S& s = t;
6885 we can extend the lifetime of the return value of the conversion
6886 operator. */
6889 {
6890 tree var;
6891 tree base_conv_type;
6893 /* Skip over the REF_BIND. */
6895 /* If the next conversion is a BASE_CONV, skip that too -- but
6896 remember that the conversion was required. */
6898 {
6901 }
6902 else
6904 /* Perform the remainder of the conversion. */
6910 tf_warning_or_error);
6913 else
6914 {
6916 {
6917 tree init;
6918 tree type;
6920 /* Create the temporary variable. */
6924 /* If the rvalue is the result of a function call it will be
6925 a TARGET_EXPR. If it is some other construct (such as a
6926 member access expression where the underlying object is
6927 itself the result of a function call), turn it into a
6928 TARGET_EXPR here. It is important that EXPR be a
6929 TARGET_EXPR below since otherwise the INIT_EXPR will
6930 attempt to make a bitwise copy of EXPR to initialize
6931 VAR. */
6934 /* Create the INIT_EXPR that will initialize the temporary
6935 variable. */
6938 {
6943 else
6946 /* We must be careful to destroy the temporary only
6947 after its initialization has taken place. If the
6948 initialization throws an exception, then the
6949 destructor should not be run. We cannot simply
6950 transform INIT into something like:
6952 (INIT, ({ CLEANUP_STMT; }))
6954 because emit_local_var always treats the
6955 initializer as a full-expression. Thus, the
6956 destructor would run too early; it would run at the
6957 end of initializing the reference variable, rather
6958 than at the end of the block enclosing the
6959 reference variable.
6961 The solution is to pass back a cleanup expression
6962 which the caller is responsible for attaching to
6963 the statement tree. */
6964 }
6965 else
6966 {
6970 static_aggregates);
6971 }
6972 /* Use its address to initialize the reference variable. */
6980 }
6981 else
6982 /* Take the address of EXPR. */
6984 /* If a BASE_CONV was required, perform it now. */
6986 expr = (perform_implicit_conversion
6988 tf_warning_or_error));
6990 }
6991 }
6992 else
6993 /* Perform the conversion. */
6996 /* Free all the conversions we allocated. */
7000 }