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1 /* Functions related to invoking methods and overloaded functions.
2 Copyright (C) 1987, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
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) \
132 convert_like_real ((CONV), (EXPR), NULL_TREE, 0, 0, \
135 #define convert_like_with_context(CONV, EXPR, FN, ARGNO) \
136 convert_like_real ((CONV), (EXPR), (FN), (ARGNO), 0, \
159 static void add_builtin_candidates
162 static void add_builtin_candidate
166 static void build_builtin_candidate
201 /* Returns nonzero iff the destructor name specified in NAME matches BASETYPE.
202 NAME can take many forms... */
204 bool
206 {
207 /* Just accept something we've already complained about. */
216 {
221 else
223 }
224 else
225 {
226 /* In the case of:
228 template <class T> struct S { ~S(); };
229 int i;
230 i.~S();
232 NAME will be a class template. */
235 }
240 }
242 /* We want the address of a function or method. We avoid creating a
243 pointer-to-member function. */
245 tree
247 {
250 /* We have to do these by hand to avoid real pointer to member
251 functions. */
253 {
255 {
259 }
261 }
262 else
266 }
268 /* Build a CALL_EXPR, we can handle FUNCTION_TYPEs, METHOD_TYPEs, or
269 POINTER_TYPE to those. Note, pointer to member function types
270 (TYPE_PTRMEMFUNC_P) must be handled by our callers. There are
271 two variants. build_call_a is the primitive taking an array of
272 arguments, while build_call_n is a wrapper that handles varargs. */
274 tree
276 {
279 else
280 {
290 }
291 }
293 tree
295 {
298 tree decl;
299 tree result_type;
300 tree fntype;
313 {
316 {
317 /* We invoke build_call directly for several library
318 functions. These may have been declared normally if
319 we're building libgcc, so we can't just check
320 DECL_ARTIFICIAL. */
325 }
326 }
327 else
330 /* We check both the decl and the type; a function may be known not to
331 throw without being declared throw(). */
345 /* Don't pass empty class objects by value. This is useful
346 for tags in STL, which are used to control overload resolution.
347 We don't need to handle other cases of copying empty classes. */
352 {
356 }
363 }
365 /* Build something of the form ptr->method (args)
366 or object.method (args). This can also build
367 calls to constructors, and find friends.
369 Member functions always take their class variable
370 as a pointer.
372 INSTANCE is a class instance.
374 NAME is the name of the method desired, usually an IDENTIFIER_NODE.
376 PARMS help to figure out what that NAME really refers to.
378 BASETYPE_PATH, if non-NULL, contains a chain from the type of INSTANCE
379 down to the real instance type to use for access checking. We need this
380 information to get protected accesses correct.
382 FLAGS is the logical disjunction of zero or more LOOKUP_
383 flags. See cp-tree.h for more info.
385 If this is all OK, calls build_function_call with the resolved
386 member function.
388 This function must also handle being called to perform
389 initialization, promotion/coercion of arguments, and
390 instantiation of default parameters.
392 Note that NAME may refer to an instance variable name. If
393 `operator()()' is defined for the type of that field, then we return
394 that result. */
396 /* New overloading code. */
404 };
407 /* The FUNCTION_DECL that will be called if this candidate is
408 selected by overload resolution. */
409 tree fn;
410 /* The arguments to use when calling this function. */
411 tree args;
412 /* The implicit conversion sequences for each of the arguments to
413 FN. */
415 /* The number of implicit conversion sequences. */
417 /* If FN is a user-defined conversion, the standard conversion
418 sequence from the type returned by FN to the desired destination
419 type. */
422 /* If FN is a member function, the binfo indicating the path used to
423 qualify the name of FN at the call site. This path is used to
424 determine whether or not FN is accessible if it is selected by
425 overload resolution. The DECL_CONTEXT of FN will always be a
426 (possibly improper) base of this binfo. */
427 tree access_path;
428 /* If FN is a non-static member function, the binfo indicating the
429 subobject to which the `this' pointer should be converted if FN
430 is selected by overload resolution. The type pointed to the by
431 the `this' pointer must correspond to the most derived class
432 indicated by the CONVERSION_PATH. */
433 tree conversion_path;
434 tree template_decl;
437 };
439 /* Returns true iff T is a null pointer constant in the sense of
440 [conv.ptr]. */
442 bool
444 {
445 /* [conv.ptr]
447 A null pointer constant is an integral constant expression
448 (_expr.const_) rvalue of integer type that evaluates to zero. */
453 {
457 }
459 }
461 /* Returns nonzero if PARMLIST consists of only default parms and/or
462 ellipsis. */
464 bool
466 {
472 }
474 /* Allocate N bytes of memory from the conversion obstack. The memory
475 is zeroed before being returned. */
479 {
482 {
485 }
489 }
491 /* Dynamically allocate a conversion. */
495 {
500 }
502 #ifdef ENABLE_CHECKING
504 /* Make sure that all memory on the conversion obstack has been
505 freed. */
507 void
509 {
513 }
517 /* Dynamically allocate an array of N conversions. */
521 {
523 }
527 {
531 /* We can't use buildl1 here because CODE could be USER_CONV, which
532 takes two arguments. In that case, the caller is responsible for
533 filling in the second argument. */
539 {
555 }
561 }
563 /* Build a representation of the identity conversion from EXPR to
564 itself. The TYPE should match the type of EXPR, if EXPR is non-NULL. */
568 {
576 }
578 /* Converting from EXPR to TYPE was ambiguous in the sense that there
579 were multiple user-defined conversions to accomplish the job.
580 Build a conversion that indicates that ambiguity. */
584 {
592 }
594 tree
596 {
600 }
602 /* Returns the standard conversion path (see [conv]) from type FROM to type
603 TO, if any. For proper handling of null pointer constants, you must
604 also pass the expression EXPR to convert from. If C_CAST_P is true,
605 this conversion is coming from a C-style cast. */
610 {
617 {
620 }
626 {
631 }
638 {
642 }
644 {
646 {
647 tree bitfield_type;
650 {
653 }
654 }
656 }
658 /* Allow conversion between `__complex__' data types. */
660 {
661 /* The standard conversion sequence to convert FROM to TO is
662 the standard conversion sequence to perform componentwise
663 conversion. */
668 {
671 }
672 else
676 }
686 {
687 /* For backwards brain damage compatibility, allow interconversion of
688 pointers and integers with a pedwarn. */
691 }
693 {
694 /* For backwards brain damage compatibility, allow interconversion of
695 enums and integers with a pedwarn. */
698 }
701 {
702 tree to_pointee;
703 tree from_pointee;
708 ;
712 {
713 from = build_pointer_type
717 }
719 {
724 && (same_type_ignoring_top_level_qualifiers_p
727 {
731 }
734 }
737 /* [conv.ptr]
739 An rvalue of type "pointer to cv D," where D is a
740 class type, can be converted to an rvalue of type
741 "pointer to cv B," where B is a base class (clause
742 _class.derived_) of D. If B is an inaccessible
743 (clause _class.access_) or ambiguous
744 (_class.member.lookup_) base class of D, a program
745 that necessitates this conversion is ill-formed.
746 Therefore, we use DERIVED_FROM_P, and do not check
747 access or uniqueness. */
749 /* If FROM is not yet complete, then we must be parsing
750 the body of a class. We know what's derived from
751 what, but we can't actually perform a
752 derived-to-base conversion. For example, in:
754 struct D : public B {
755 static const int i = sizeof((B*)(D*)0);
756 };
758 the D*-to-B* conversion is a reinterpret_cast, not a
759 static_cast. */
761 {
762 from =
768 }
771 {
774 }
775 else
776 {
779 }
784 /* In a C-style cast, we ignore CV-qualification because we
785 are allowed to perform a static_cast followed by a
786 const_cast. */
791 /* converting from string constant to char *. */
794 {
797 }
798 else
802 }
804 {
824 }
826 {
827 /* [conv.bool]
829 An rvalue of arithmetic, enumeration, pointer, or pointer to
830 member type can be converted to an rvalue of type bool. */
835 {
843 }
846 }
847 /* We don't check for ENUMERAL_TYPE here because there are no standard
848 conversions to enum type. */
851 {
856 /* Give this a better rank if it's a promotion. */
860 }
866 {
870 /* The derived-to-base conversion indicates the initialization
871 of a parameter with base type from an object of a derived
872 type. A temporary object is created to hold the result of
873 the conversion unless we're binding directly to a reference. */
875 }
876 else
880 }
882 /* Returns nonzero if T1 is reference-related to T2. */
884 static bool
886 {
890 /* [dcl.init.ref]
892 Given types "cv1 T1" and "cv2 T2," "cv1 T1" is reference-related
893 to "cv2 T2" if T1 is the same type as T2, or T1 is a base class
894 of T2. */
898 }
900 /* Returns nonzero if T1 is reference-compatible with T2. */
902 static bool
904 {
905 /* [dcl.init.ref]
907 "cv1 T1" is reference compatible with "cv2 T2" if T1 is
908 reference-related to T2 and cv1 is the same cv-qualification as,
909 or greater cv-qualification than, cv2. */
912 }
914 /* Determine whether or not the EXPR (of class type S) can be
915 converted to T as in [over.match.ref]. */
919 {
920 tree conversions;
921 tree arglist;
923 tree t;
932 /* [over.match.ref]
934 Assuming that "cv1 T" is the underlying type of the reference
935 being initialized, and "cv S" is the type of the initializer
936 expression, with S a class type, the candidate functions are
937 selected as follows:
939 --The conversion functions of S and its base classes are
940 considered. Those that are not hidden within S and yield type
941 "reference to cv2 T2", where "cv1 T" is reference-compatible
942 (_dcl.init.ref_) with "cv2 T2", are candidate functions.
944 The argument list has one argument, which is the initializer
945 expression. */
949 /* Conceptually, we should take the address of EXPR and put it in
950 the argument list. Unfortunately, however, that can result in
951 error messages, which we should not issue now because we are just
952 trying to find a conversion operator. Therefore, we use NULL,
953 cast to the appropriate type. */
960 {
964 {
970 /* If this is a template function, try to get an exact
971 match. */
973 {
976 NULL_TREE,
977 arglist,
978 reference_type,
981 LOOKUP_NORMAL,
982 DEDUCE_CONV);
985 {
986 /* Now, see if the conversion function really returns
987 an lvalue of the appropriate type. From the
988 point of view of unification, simply returning an
989 rvalue of the right type is good enough. */
994 {
997 }
998 }
999 }
1005 LOOKUP_NORMAL);
1008 {
1010 /* Build a standard conversion sequence indicating the
1011 binding from the reference type returned by the
1012 function to the desired REFERENCE_TYPE. */
1013 identity_conv
1016 NULL_TREE);
1017 cand->second_conv
1018 = (direct_reference_binding
1024 }
1025 }
1027 }
1030 /* If none of the conversion functions worked out, let our caller
1031 know. */
1039 /* Now that we know that this is the function we're going to use fix
1040 the dummy first argument. */
1045 /* Build a user-defined conversion sequence representing the
1046 conversion. */
1052 /* Merge it with the standard conversion sequence from the
1053 conversion function's return type to the desired type. */
1060 }
1062 /* A reference of the indicated TYPE is being bound directly to the
1063 expression represented by the implicit conversion sequence CONV.
1064 Return a conversion sequence for this binding. */
1068 {
1069 tree t;
1076 /* [over.ics.rank]
1078 When a parameter of reference type binds directly
1079 (_dcl.init.ref_) to an argument expression, the implicit
1080 conversion sequence is the identity conversion, unless the
1081 argument expression has a type that is a derived class of the
1082 parameter type, in which case the implicit conversion sequence is
1083 a derived-to-base Conversion.
1085 If the parameter binds directly to the result of applying a
1086 conversion function to the argument expression, the implicit
1087 conversion sequence is a user-defined conversion sequence
1088 (_over.ics.user_), with the second standard conversion sequence
1089 either an identity conversion or, if the conversion function
1090 returns an entity of a type that is a derived class of the
1091 parameter type, a derived-to-base conversion. */
1093 {
1094 /* Represent the derived-to-base conversion. */
1096 /* We will actually be binding to the base-class subobject in
1097 the derived class, so we mark this conversion appropriately.
1098 That way, convert_like knows not to generate a temporary. */
1100 }
1102 }
1104 /* Returns the conversion path from type FROM to reference type TO for
1105 purposes of reference binding. For lvalue binding, either pass a
1106 reference type to FROM or an lvalue expression to EXPR. If the
1107 reference will be bound to a temporary, NEED_TEMPORARY_P is set for
1108 the conversion returned. If C_CAST_P is true, this
1109 conversion is coming from a C-style cast. */
1113 {
1122 {
1127 }
1130 {
1131 /* Anything with reference type is an lvalue. */
1134 }
1138 /* Figure out whether or not the types are reference-related and
1139 reference compatible. We have do do this after stripping
1140 references from FROM. */
1142 /* If this is a C cast, first convert to an appropriately qualified
1143 type, so that we can later do a const_cast to the desired type. */
1149 /* Directly bind reference when target expression's type is compatible with
1150 the reference and expression is an lvalue. In DR391, the wording in
1151 [8.5.3/5 dcl.init.ref] is changed to also require direct bindings for
1152 const and rvalue references to rvalues of compatible class type. */
1154 && (lvalue_p
1157 {
1158 /* [dcl.init.ref]
1160 If the initializer expression
1162 -- is an lvalue (but not an lvalue for a bit-field), and "cv1 T1"
1163 is reference-compatible with "cv2 T2,"
1165 the reference is bound directly to the initializer expression
1166 lvalue.
1168 [...]
1169 If the initializer expression is an rvalue, with T2 a class type,
1170 and "cv1 T1" is reference-compatible with "cv2 T2", the reference
1171 is bound to the object represented by the rvalue or to a sub-object
1172 within that object. */
1178 /* The top-level caller requested that we pretend that the lvalue
1179 be treated as an rvalue. */
1181 else
1182 conv->rvaluedness_matches_p
1187 /* For the purposes of overload resolution, we ignore the fact
1188 this expression is a bitfield or packed field. (In particular,
1189 [over.ics.ref] says specifically that a function with a
1190 non-const reference parameter is viable even if the
1191 argument is a bitfield.)
1193 However, when we actually call the function we must create
1194 a temporary to which to bind the reference. If the
1195 reference is volatile, or isn't const, then we cannot make
1196 a temporary, so we just issue an error when the conversion
1197 actually occurs. */
1201 }
1202 /* [class.conv.fct] A conversion function is never used to convert a
1203 (possibly cv-qualified) object to the (possibly cv-qualified) same
1204 object type (or a reference to it), to a (possibly cv-qualified) base
1205 class of that type (or a reference to it).... */
1208 {
1209 /* [dcl.init.ref]
1211 If the initializer expression
1213 -- has a class type (i.e., T2 is a class type) can be
1214 implicitly converted to an lvalue of type "cv3 T3," where
1215 "cv1 T1" is reference-compatible with "cv3 T3". (this
1216 conversion is selected by enumerating the applicable
1217 conversion functions (_over.match.ref_) and choosing the
1218 best one through overload resolution. (_over.match_).
1220 the reference is bound to the lvalue result of the conversion
1221 in the second case. */
1225 }
1227 /* From this point on, we conceptually need temporaries, even if we
1228 elide them. Only the cases above are "direct bindings". */
1232 /* [over.ics.rank]
1234 When a parameter of reference type is not bound directly to an
1235 argument expression, the conversion sequence is the one required
1236 to convert the argument expression to the underlying type of the
1237 reference according to _over.best.ics_. Conceptually, this
1238 conversion sequence corresponds to copy-initializing a temporary
1239 of the underlying type with the argument expression. Any
1240 difference in top-level cv-qualification is subsumed by the
1241 initialization itself and does not constitute a conversion. */
1243 /* [dcl.init.ref]
1245 Otherwise, the reference shall be to a non-volatile const type.
1247 Under C++0x, [8.5.3/5 dcl.init.ref] it may also be an rvalue reference */
1251 /* [dcl.init.ref]
1253 Otherwise, a temporary of type "cv1 T1" is created and
1254 initialized from the initializer expression using the rules for a
1255 non-reference copy initialization. If T1 is reference-related to
1256 T2, cv1 must be the same cv-qualification as, or greater
1257 cv-qualification than, cv2; otherwise, the program is ill-formed. */
1261 /* We're generating a temporary now, but don't bind any more in the
1262 conversion (specifically, don't slice the temporary returned by a
1263 conversion operator). */
1267 flags);
1272 /* This reference binding, unlike those above, requires the
1273 creation of a temporary. */
1278 }
1280 /* Returns the implicit conversion sequence (see [over.ics]) from type
1281 FROM to type TO. The optional expression EXPR may affect the
1282 conversion. FLAGS are the usual overloading flags. Only
1283 LOOKUP_NO_CONVERSION is significant. If C_CAST_P is true, this
1284 conversion is coming from a C-style cast. */
1289 {
1298 else
1308 {
1317 /* We used to try to bind a reference to a temporary here, but that
1318 is now handled after the recursive call to this function at the end
1319 of reference_binding. */
1321 }
1324 }
1326 /* Add a new entry to the list of candidates. Used by the add_*_candidate
1327 functions. */
1335 {
1350 }
1352 /* Create an overload candidate for the function or method FN called with
1353 the argument list ARGLIST and add it to CANDIDATES. FLAGS is passed on
1354 to implicit_conversion.
1356 CTYPE, if non-NULL, is the type we want to pretend this function
1357 comes from for purposes of overload resolution. */
1364 {
1369 tree orig_arglist;
1372 /* At this point we should not see any functions which haven't been
1373 explicitly declared, except for friend functions which will have
1374 been found using argument dependent lookup. */
1377 /* The `this', `in_chrg' and VTT arguments to constructors are not
1378 considered in overload resolution. */
1380 {
1384 }
1385 else
1391 /* 13.3.2 - Viable functions [over.match.viable]
1392 First, to be a viable function, a candidate function shall have enough
1393 parameters to agree in number with the arguments in the list.
1395 We need to check this first; otherwise, checking the ICSes might cause
1396 us to produce an ill-formed template instantiation. */
1400 {
1404 }
1409 /* Make sure there are default args for the rest of the parms. */
1416 /* Second, for F to be a viable function, there shall exist for each
1417 argument an implicit conversion sequence that converts that argument
1418 to the corresponding parameter of F. */
1424 {
1437 {
1440 /* The type of the implicit object parameter ('this') for
1441 overload resolution is not always the same as for the
1442 function itself; conversion functions are considered to
1443 be members of the class being converted, and functions
1444 introduced by a using-declaration are considered to be
1445 members of the class that uses them.
1447 Since build_over_call ignores the ICS for the `this'
1448 parameter, we can just change the parm type. */
1450 {
1451 parmtype
1455 }
1459 }
1460 else
1461 {
1464 }
1471 {
1474 }
1482 }
1484 out:
1487 }
1489 /* Create an overload candidate for the conversion function FN which will
1490 be invoked for expression OBJ, producing a pointer-to-function which
1491 will in turn be called with the argument list ARGLIST, and add it to
1492 CANDIDATES. FLAGS is passed on to implicit_conversion.
1494 Actually, we don't really care about FN; we care about the type it
1495 converts to. There may be multiple conversion functions that will
1496 convert to that type, and we rely on build_user_type_conversion_1 to
1497 choose the best one; so when we create our candidate, we record the type
1498 instead of the function. */
1503 {
1520 /* Don't bother looking up the same type twice. */
1525 {
1532 flags);
1538 else
1539 {
1542 }
1557 }
1567 }
1569 static void
1573 {
1587 {
1594 {
1596 /* We need something for printing the candidate. */
1598 }
1602 }
1604 /* For COND_EXPR we rearranged the arguments; undo that now. */
1606 {
1613 else
1615 }
1621 viable);
1622 }
1624 static bool
1626 {
1628 }
1630 /* Returns nonzero if TYPE is a promoted arithmetic type. */
1632 static bool
1634 {
1635 /* [over.built]
1637 In this section, the term promoted integral type is used to refer
1638 to those integral types which are preserved by integral promotion
1639 (including e.g. int and long but excluding e.g. char).
1640 Similarly, the term promoted arithmetic type refers to promoted
1641 integral types plus floating types. */
1645 }
1647 /* Create any builtin operator overload candidates for the operator in
1648 question given the converted operand types TYPE1 and TYPE2. The other
1649 args are passed through from add_builtin_candidates to
1650 build_builtin_candidate.
1652 TYPE1 and TYPE2 may not be permissible, and we must filter them.
1653 If CODE is requires candidates operands of the same type of the kind
1654 of which TYPE1 and TYPE2 are, we add both candidates
1655 CODE (TYPE1, TYPE1) and CODE (TYPE2, TYPE2). */
1657 static void
1661 {
1663 {
1671 }
1674 {
1676 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
1677 and VQ is either volatile or empty, there exist candidate operator
1678 functions of the form
1679 VQ T& operator++(VQ T&);
1680 T operator++(VQ T&, int);
1681 5 For every pair T, VQ), where T is an enumeration type or an arithmetic
1682 type other than bool, and VQ is either volatile or empty, there exist
1683 candidate operator functions of the form
1684 VQ T& operator--(VQ T&);
1685 T operator--(VQ T&, int);
1686 6 For every pair T, VQ), where T is a cv-qualified or cv-unqualified
1687 complete object type, and VQ is either volatile or empty, there exist
1688 candidate operator functions of the form
1689 T*VQ& operator++(T*VQ&);
1690 T*VQ& operator--(T*VQ&);
1691 T* operator++(T*VQ&, int);
1692 T* operator--(T*VQ&, int); */
1701 {
1704 }
1707 /* 7 For every cv-qualified or cv-unqualified complete object type T, there
1708 exist candidate operator functions of the form
1710 T& operator*(T*);
1712 8 For every function type T, there exist candidate operator functions of
1713 the form
1714 T& operator*(T*); */
1723 /* 9 For every type T, there exist candidate operator functions of the form
1724 T* operator+(T*);
1726 10For every promoted arithmetic type T, there exist candidate operator
1727 functions of the form
1728 T operator+(T);
1729 T operator-(T); */
1739 /* 11For every promoted integral type T, there exist candidate operator
1740 functions of the form
1741 T operator~(T); */
1748 /* 12For every quintuple C1, C2, T, CV1, CV2), where C2 is a class type, C1
1749 is the same type as C2 or is a derived class of C2, T is a complete
1750 object type or a function type, and CV1 and CV2 are cv-qualifier-seqs,
1751 there exist candidate operator functions of the form
1752 CV12 T& operator->*(CV1 C1*, CV2 T C2::*);
1753 where CV12 is the union of CV1 and CV2. */
1758 {
1766 }
1769 /* 13For every pair of promoted arithmetic types L and R, there exist can-
1770 didate operator functions of the form
1771 LR operator*(L, R);
1772 LR operator/(L, R);
1773 LR operator+(L, R);
1774 LR operator-(L, R);
1775 bool operator<(L, R);
1776 bool operator>(L, R);
1777 bool operator<=(L, R);
1778 bool operator>=(L, R);
1779 bool operator==(L, R);
1780 bool operator!=(L, R);
1781 where LR is the result of the usual arithmetic conversions between
1782 types L and R.
1784 14For every pair of types T and I, where T is a cv-qualified or cv-
1785 unqualified complete object type and I is a promoted integral type,
1786 there exist candidate operator functions of the form
1787 T* operator+(T*, I);
1788 T& operator[](T*, I);
1789 T* operator-(T*, I);
1790 T* operator+(I, T*);
1791 T& operator[](I, T*);
1793 15For every T, where T is a pointer to complete object type, there exist
1794 candidate operator functions of the form112)
1795 ptrdiff_t operator-(T, T);
1797 16For every pointer or enumeration type T, there exist candidate operator
1798 functions of the form
1799 bool operator<(T, T);
1800 bool operator>(T, T);
1801 bool operator<=(T, T);
1802 bool operator>=(T, T);
1803 bool operator==(T, T);
1804 bool operator!=(T, T);
1806 17For every pointer to member type T, there exist candidate operator
1807 functions of the form
1808 bool operator==(T, T);
1809 bool operator!=(T, T); */
1815 {
1818 }
1831 {
1834 }
1836 {
1839 }
1840 /* Fall through. */
1857 {
1860 }
1864 {
1867 }
1875 {
1878 }
1880 {
1883 }
1886 /* 18For every pair of promoted integral types L and R, there exist candi-
1887 date operator functions of the form
1888 LR operator%(L, R);
1889 LR operator&(L, R);
1890 LR operator^(L, R);
1891 LR operator|(L, R);
1892 L operator<<(L, R);
1893 L operator>>(L, R);
1894 where LR is the result of the usual arithmetic conversions between
1895 types L and R. */
1907 /* 19For every triple L, VQ, R), where L is an arithmetic or enumeration
1908 type, VQ is either volatile or empty, and R is a promoted arithmetic
1909 type, there exist candidate operator functions of the form
1910 VQ L& operator=(VQ L&, R);
1911 VQ L& operator*=(VQ L&, R);
1912 VQ L& operator/=(VQ L&, R);
1913 VQ L& operator+=(VQ L&, R);
1914 VQ L& operator-=(VQ L&, R);
1916 20For every pair T, VQ), where T is any type and VQ is either volatile
1917 or empty, there exist candidate operator functions of the form
1918 T*VQ& operator=(T*VQ&, T*);
1920 21For every pair T, VQ), where T is a pointer to member type and VQ is
1921 either volatile or empty, there exist candidate operator functions of
1922 the form
1923 VQ T& operator=(VQ T&, T);
1925 22For every triple T, VQ, I), where T is a cv-qualified or cv-
1926 unqualified complete object type, VQ is either volatile or empty, and
1927 I is a promoted integral type, there exist candidate operator func-
1928 tions of the form
1929 T*VQ& operator+=(T*VQ&, I);
1930 T*VQ& operator-=(T*VQ&, I);
1932 23For every triple L, VQ, R), where L is an integral or enumeration
1933 type, VQ is either volatile or empty, and R is a promoted integral
1934 type, there exist candidate operator functions of the form
1936 VQ L& operator%=(VQ L&, R);
1937 VQ L& operator<<=(VQ L&, R);
1938 VQ L& operator>>=(VQ L&, R);
1939 VQ L& operator&=(VQ L&, R);
1940 VQ L& operator^=(VQ L&, R);
1941 VQ L& operator|=(VQ L&, R); */
1945 {
1949 {
1952 }
1978 {
1981 }
1986 }
1991 /* [over.built]
1993 For every pair of promoted arithmetic types L and R, there
1994 exist candidate operator functions of the form
1996 LR operator?(bool, L, R);
1998 where LR is the result of the usual arithmetic conversions
1999 between types L and R.
2001 For every type T, where T is a pointer or pointer-to-member
2002 type, there exist candidate operator functions of the form T
2003 operator?(bool, T, T); */
2007 /* That's OK. */
2010 /* Otherwise, the types should be pointers. */
2015 /* We don't check that the two types are the same; the logic
2016 below will actually create two candidates; one in which both
2017 parameter types are TYPE1, and one in which both parameter
2018 types are TYPE2. */
2023 }
2025 /* If we're dealing with two pointer types or two enumeral types,
2026 we need candidates for both of them. */
2035 {
2036 build_builtin_candidate
2038 build_builtin_candidate
2041 }
2043 build_builtin_candidate
2045 }
2047 tree
2049 {
2055 }
2057 /* There are three conditions of builtin candidates:
2059 1) bool-taking candidates. These are the same regardless of the input.
2060 2) pointer-pair taking candidates. These are generated for each type
2061 one of the input types converts to.
2062 3) arithmetic candidates. According to the standard, we should generate
2063 all of these, but I'm trying not to...
2065 Here we generate a superset of the possible candidates for this particular
2066 case. That is a subset of the full set the standard defines, plus some
2067 other cases which the standard disallows. add_builtin_candidate will
2068 filter out the invalid set. */
2070 static void
2074 {
2078 /* TYPES[i] is the set of possible builtin-operator parameter types
2079 we will consider for the Ith argument. These are represented as
2080 a TREE_LIST; the TREE_VALUE of each node is the potential
2081 parameter type. */
2085 {
2088 else
2090 }
2093 {
2094 /* 4 For every pair T, VQ), where T is an arithmetic or enumeration type,
2095 and VQ is either volatile or empty, there exist candidate operator
2096 functions of the form
2097 VQ T& operator++(VQ T&); */
2107 /* 24There also exist candidate operator functions of the form
2108 bool operator!(bool);
2109 bool operator&&(bool, bool);
2110 bool operator||(bool, bool); */
2113 build_builtin_candidate
2120 build_builtin_candidate
2138 /* Fall through. */
2142 }
2147 {
2149 ;
2151 {
2152 tree convs;
2160 {
2167 }
2173 {
2186 {
2192 }
2196 }
2197 }
2198 else
2199 {
2205 {
2211 }
2213 }
2214 }
2216 /* Run through the possible parameter types of both arguments,
2217 creating candidates with those parameter types. */
2219 {
2222 add_builtin_candidate
2225 else
2226 add_builtin_candidate
2229 }
2230 }
2233 /* If TMPL can be successfully instantiated as indicated by
2234 EXPLICIT_TARGS and ARGLIST, adds the instantiation to CANDIDATES.
2236 TMPL is the template. EXPLICIT_TARGS are any explicit template
2237 arguments. ARGLIST is the arguments provided at the call-site.
2238 The RETURN_TYPE is the desired type for conversion operators. If
2239 OBJ is NULL_TREE, FLAGS and CTYPE are as for add_function_candidate.
2240 If an OBJ is supplied, FLAGS and CTYPE are ignored, and OBJ is as for
2241 add_conv_candidate. */
2248 unification_kind_t strict)
2249 {
2255 tree fn;
2257 /* We don't do deduction on the in-charge parameter, the VTT
2258 parameter or 'this'. */
2268 args_without_in_chrg,
2278 /* In [class.copy]:
2280 A member function template is never instantiated to perform the
2281 copy of a class object to an object of its class type.
2283 It's a little unclear what this means; the standard explicitly
2284 does allow a template to be used to copy a class. For example,
2285 in:
2287 struct A {
2288 A(A&);
2289 template <class T> A(const T&);
2290 };
2291 const A f ();
2292 void g () { A a (f ()); }
2294 the member template will be used to make the copy. The section
2295 quoted above appears in the paragraph that forbids constructors
2296 whose only parameter is (a possibly cv-qualified variant of) the
2297 class type, and a logical interpretation is that the intent was
2298 to forbid the instantiation of member templates which would then
2299 have that form. */
2301 {
2304 ctype))
2306 }
2309 /* Aha, this is a conversion function. */
2312 else
2317 /* This situation can occur if a member template of a template
2318 class is specialized. Then, instantiate_template might return
2319 an instantiation of the specialization, in which case the
2320 DECL_TI_TEMPLATE field will point at the original
2321 specialization. For example:
2323 template <class T> struct S { template <class U> void f(U);
2324 template <> void f(int) {}; };
2325 S<double> sd;
2326 sd.f(3);
2328 Here, TMPL will be template <class U> S<double>::f(U).
2329 And, instantiate template will give us the specialization
2330 template <> S<double>::f(int). But, the DECL_TI_TEMPLATE field
2331 for this will point at template <class T> template <> S<T>::f(int),
2332 so that we can find the definition. For the purposes of
2333 overload resolution, however, we want the original TMPL. */
2335 else
2339 }
2346 unification_kind_t strict)
2347 {
2348 return
2353 }
2360 {
2361 return
2365 }
2367 /* The CANDS are the set of candidates that were considered for
2368 overload resolution. Return the set of viable candidates. If none
2369 of the candidates were viable, set *ANY_VIABLE_P to true. STRICT_P
2370 is true if a candidate should be considered viable only if it is
2371 strictly viable. */
2377 {
2388 {
2391 {
2397 }
2398 else
2400 }
2403 }
2405 static bool
2407 {
2412 }
2414 /* OBJ is being used in an expression like "OBJ.f (...)". In other
2415 words, it is about to become the "this" pointer for a member
2416 function call. Take the address of the object. */
2418 static tree
2420 {
2421 /* In a template, we are only concerned about the type of the
2422 expression, so we can take a shortcut. */
2427 }
2429 /* Returns true iff functions are equivalent. Equivalent functions are
2430 not '==' only if one is a function-local extern function or if
2431 both are extern "C". */
2435 {
2440 }
2442 /* Print information about one overload candidate CANDIDATE. MSGSTR
2443 is the text to print before the candidate itself.
2445 NOTE: Unlike most diagnostic functions in GCC, MSGSTR is expected
2446 to have been run through gettext by the caller. This wart makes
2447 life simpler in print_z_candidates and for the translators. */
2449 static void
2451 {
2453 {
2463 else
2466 }
2471 else
2473 }
2475 static void
2477 {
2482 /* There may be duplicates in the set of candidates. We put off
2483 checking this condition as long as possible, since we have no way
2484 to eliminate duplicates from a set of functions in less than n^2
2485 time. Now we are about to emit an error message, so it is more
2486 permissible to go slowly. */
2488 {
2490 /* Skip builtin candidates and conversion functions. */
2495 {
2499 else
2501 }
2502 }
2510 {
2511 /* Indent successive candidates by the width of the translation
2512 of the above string. */
2519 do
2520 {
2523 }
2525 }
2526 }
2528 /* USER_SEQ is a user-defined conversion sequence, beginning with a
2529 USER_CONV. STD_SEQ is the standard conversion sequence applied to
2530 the result of the conversion function to convert it to the final
2531 desired type. Merge the two sequences into a single sequence,
2532 and return the merged sequence. */
2536 {
2541 /* Find the end of the second conversion sequence. */
2546 /* Replace the identity conversion with the user conversion
2547 sequence. */
2550 /* The entire sequence is a user-conversion sequence. */
2554 }
2556 /* Returns the best overload candidate to perform the requested
2557 conversion. This function is used for three the overloading situations
2558 described in [over.match.copy], [over.match.conv], and [over.match.ref].
2559 If TOTYPE is a REFERENCE_TYPE, we're trying to find an lvalue binding as
2560 per [dcl.init.ref], so we ignore temporary bindings. */
2564 {
2574 /* We represent conversion within a hierarchy using RVALUE_CONV and
2575 BASE_CONV, as specified by [over.best.ics]; these become plain
2576 constructor calls, as specified in [dcl.init]. */
2584 {
2589 {
2590 /* [class.conv.fct] A conversion function is never used to
2591 convert a (possibly cv-qualified) object to the (possibly
2592 cv-qualified) same object type (or a reference to it), to a
2593 (possibly cv-qualified) base class of that type (or a
2594 reference to it)... */
2595 }
2596 else
2598 }
2603 /* It's OK to bind a temporary for converting constructor arguments, but
2604 not in converting the return value of a conversion operator. */
2609 {
2610 tree t;
2616 /* We should never try to call the abstract or base constructor
2617 from here. */
2621 }
2623 {
2633 flags,
2634 DEDUCE_CALL);
2635 else
2639 flags);
2643 }
2649 {
2650 tree fns;
2653 /* If we are called to convert to a reference type, we are trying to
2654 find an lvalue binding, so don't even consider temporaries. If
2655 we don't find an lvalue binding, the caller will try again to
2656 look for a temporary binding. */
2661 {
2664 /* [over.match.funcs] For conversion functions, the function
2665 is considered to be a member of the class of the implicit
2666 object argument for the purpose of defining the type of
2667 the implicit object parameter.
2669 So we pass fromtype as CTYPE to add_*_candidate. */
2673 NULL_TREE,
2676 conversion_path,
2677 flags,
2678 DEDUCE_CONV);
2679 else
2681 args,
2683 conversion_path,
2684 flags);
2687 {
2688 conversion *ics
2700 }
2701 }
2702 }
2710 {
2712 {
2716 }
2723 /* If there are viable candidates, don't set ICS_BAD_FLAG; an
2724 ambiguous conversion is no worse than another user-defined
2725 conversion. */
2728 }
2730 /* Build the user conversion sequence. */
2731 conv = build_conv
2738 /* Combine it with the second conversion sequence. */
2746 }
2748 tree
2750 {
2755 {
2760 }
2762 }
2764 /* Do any initial processing on the arguments to a function call. */
2766 static tree
2768 {
2769 tree t;
2771 {
2777 {
2780 }
2783 }
2785 }
2787 /* Perform overload resolution on FN, which is called with the ARGS.
2789 Return the candidate function selected by overload resolution, or
2790 NULL if the event that overload resolution failed. In the case
2791 that overload resolution fails, *CANDIDATES will be the set of
2792 candidates considered, and ANY_VIABLE_P will be set to true or
2793 false to indicate whether or not any of the candidates were
2794 viable.
2796 The ARGS should already have gone through RESOLVE_ARGS before this
2797 function is called. */
2801 tree args,
2804 {
2812 /* Check FN and ARGS. */
2820 {
2824 }
2826 /* Add the various candidate functions. */
2830 LOOKUP_NORMAL,
2831 candidates);
2839 }
2841 /* Return an expression for a call to FN (a namespace-scope function,
2842 or a static member function) with the ARGS. */
2844 tree
2846 {
2850 tree result;
2856 /* If this function was found without using argument dependent
2857 lookup, then we want to ignore any undeclared friend
2858 functions. */
2860 {
2865 {
2869 }
2870 }
2872 /* Get the high-water mark for the CONVERSION_OBSTACK. */
2878 {
2886 else
2892 }
2893 else
2896 /* Free all the conversions we allocated. */
2900 }
2902 /* Build a call to a global operator new. FNNAME is the name of the
2903 operator (either "operator new" or "operator new[]") and ARGS are
2904 the arguments provided. *SIZE points to the total number of bytes
2905 required by the allocation, and is updated if that is changed here.
2906 *COOKIE_SIZE is non-NULL if a cookie should be used. If this
2907 function determines that no cookie should be used, after all,
2908 *COOKIE_SIZE is set to NULL_TREE. If FN is non-NULL, it will be
2909 set, upon return, to the allocation function called. */
2911 tree
2915 {
2916 tree fns;
2928 /* Based on:
2930 [expr.new]
2932 If this lookup fails to find the name, or if the allocated type
2933 is not a class type, the allocation function's name is looked
2934 up in the global scope.
2936 we disregard block-scope declarations of "operator new". */
2939 /* Figure out what function is being called. */
2942 /* If no suitable function could be found, issue an error message
2943 and give up. */
2945 {
2949 else
2955 }
2957 /* If a cookie is required, add some extra space. Whether
2958 or not a cookie is required cannot be determined until
2959 after we know which function was called. */
2961 {
2964 {
2966 /* In G++ 3.2, the check was implemented incorrectly; it
2967 looked at the placement expression, rather than the
2968 type of the function. */
2971 ptr_type_node))
2973 }
2974 else
2975 {
2976 tree arg_types;
2979 /* Skip the size_t parameter. */
2981 /* Check the remaining parameters (if any). */
2985 ptr_type_node))
2987 }
2988 /* If we need a cookie, adjust the number of bytes allocated. */
2990 {
2991 /* Update the total size. */
2993 /* Update the argument list to reflect the adjusted size. */
2995 }
2996 else
2998 }
3000 /* Tell our caller which function we decided to call. */
3004 /* Build the CALL_EXPR. */
3006 }
3008 static tree
3010 {
3019 {
3020 /* It's no good looking for an overloaded operator() on a
3021 pointer-to-member-function. */
3022 error ("pointer-to-member function %E cannot be called without an object; consider using .* or ->*", obj);
3024 }
3027 {
3031 }
3032 else
3040 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3044 {
3049 {
3057 else
3058 add_function_candidate
3061 }
3062 }
3067 {
3079 {
3082 add_template_conv_candidate
3086 else
3090 }
3091 }
3095 {
3099 }
3100 else
3101 {
3104 {
3108 }
3109 /* Since cand->fn will be a type, not a function, for a conversion
3110 function, we must be careful not to unconditionally look at
3111 DECL_NAME here. */
3115 else
3116 {
3120 }
3121 }
3123 /* Free all the conversions we allocated. */
3127 }
3129 static void
3132 {
3137 else
3141 {
3165 else
3169 }
3170 }
3172 /* Return the implicit conversion sequence that could be used to
3173 convert E1 to E2 in [expr.cond]. */
3177 {
3183 /* [expr.cond]
3185 If E2 is an lvalue: E1 can be converted to match E2 if E1 can be
3186 implicitly converted (clause _conv_) to the type "reference to
3187 T2", subject to the constraint that in the conversion the
3188 reference must bind directly (_dcl.init.ref_) to E1. */
3190 {
3192 t1,
3193 e1,
3195 LOOKUP_NO_TEMP_BIND);
3198 }
3200 /* [expr.cond]
3202 If E1 and E2 have class type, and the underlying class types are
3203 the same or one is a base class of the other: E1 can be converted
3204 to match E2 if the class of T2 is the same type as, or a base
3205 class of, the class of T1, and the cv-qualification of T2 is the
3206 same cv-qualification as, or a greater cv-qualification than, the
3207 cv-qualification of T1. If the conversion is applied, E1 is
3208 changed to an rvalue of type T2 that still refers to the original
3209 source class object (or the appropriate subobject thereof). */
3212 {
3214 {
3219 else
3222 }
3223 else
3225 }
3226 else
3227 /* [expr.cond]
3229 Otherwise: E1 can be converted to match E2 if E1 can be implicitly
3230 converted to the type that expression E2 would have if E2 were
3231 converted to an rvalue (or the type it has, if E2 is an rvalue). */
3233 LOOKUP_NORMAL);
3234 }
3236 /* Implement [expr.cond]. ARG1, ARG2, and ARG3 are the three
3237 arguments to the conditional expression. */
3239 tree
3241 {
3242 tree arg2_type;
3243 tree arg3_type;
3251 /* As a G++ extension, the second argument to the conditional can be
3252 omitted. (So that `a ? : c' is roughly equivalent to `a ? a :
3253 c'.) If the second operand is omitted, make sure it is
3254 calculated only once. */
3256 {
3260 /* Make sure that lvalues remain lvalues. See g++.oliva/ext1.C. */
3263 else
3265 }
3267 /* [expr.cond]
3269 The first expr ession is implicitly converted to bool (clause
3270 _conv_). */
3273 /* If something has already gone wrong, just pass that fact up the
3274 tree. */
3280 /* [expr.cond]
3282 If either the second or the third operand has type (possibly
3283 cv-qualified) void, then the lvalue-to-rvalue (_conv.lval_),
3284 array-to-pointer (_conv.array_), and function-to-pointer
3285 (_conv.func_) standard conversions are performed on the second
3286 and third operands. */
3290 {
3291 /* Do the conversions. We don't these for `void' type arguments
3292 since it can't have any effect and since decay_conversion
3293 does not handle that case gracefully. */
3301 /* [expr.cond]
3303 One of the following shall hold:
3305 --The second or the third operand (but not both) is a
3306 throw-expression (_except.throw_); the result is of the
3307 type of the other and is an rvalue.
3309 --Both the second and the third operands have type void; the
3310 result is of type void and is an rvalue.
3312 We must avoid calling force_rvalue for expressions of type
3313 "void" because it will complain that their value is being
3314 used. */
3317 {
3322 }
3325 {
3330 }
3333 else
3334 {
3337 "is of type %<void%>, "
3338 "but the third operand is neither a throw-expression "
3340 else
3342 "is of type %<void%>, "
3343 "but the second operand is neither a throw-expression "
3346 }
3350 }
3351 /* [expr.cond]
3353 Otherwise, if the second and third operand have different types,
3354 and either has (possibly cv-qualified) class type, an attempt is
3355 made to convert each of those operands to the type of the other. */
3358 {
3362 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3368 /* [expr.cond]
3370 If both can be converted, or one can be converted but the
3371 conversion is ambiguous, the program is ill-formed. If
3372 neither can be converted, the operands are left unchanged and
3373 further checking is performed as described below. If exactly
3374 one conversion is possible, that conversion is applied to the
3375 chosen operand and the converted operand is used in place of
3376 the original operand for the remainder of this section. */
3381 {
3385 }
3387 {
3391 /* Even if CONV2 is a valid conversion, the result of the
3392 conversion may be invalid. For example, if ARG3 has type
3393 "volatile X", and X does not have a copy constructor
3394 accepting a "volatile X&", then even if ARG2 can be
3395 converted to X, the conversion will fail. */
3398 }
3400 {
3406 }
3408 /* Free all the conversions we allocated. */
3414 /* If, after the conversion, both operands have class type,
3415 treat the cv-qualification of both operands as if it were the
3416 union of the cv-qualification of the operands.
3418 The standard is not clear about what to do in this
3419 circumstance. For example, if the first operand has type
3420 "const X" and the second operand has a user-defined
3421 conversion to "volatile X", what is the type of the second
3422 operand after this step? Making it be "const X" (matching
3423 the first operand) seems wrong, as that discards the
3424 qualification without actually performing a copy. Leaving it
3425 as "volatile X" seems wrong as that will result in the
3426 conditional expression failing altogether, even though,
3427 according to this step, the one operand could be converted to
3428 the type of the other. */
3436 }
3438 /* [expr.cond]
3440 If the second and third operands are lvalues and have the same
3441 type, the result is of that type and is an lvalue. */
3445 {
3448 }
3450 /* [expr.cond]
3452 Otherwise, the result is an rvalue. If the second and third
3453 operand do not have the same type, and either has (possibly
3454 cv-qualified) class type, overload resolution is used to
3455 determine the conversions (if any) to be applied to the operands
3456 (_over.match.oper_, _over.built_). */
3460 {
3465 /* Rearrange the arguments so that add_builtin_candidate only has
3466 to know about two args. In build_builtin_candidates, the
3467 arguments are unscrambled. */
3472 COND_EXPR,
3473 NOP_EXPR,
3475 args,
3476 LOOKUP_NORMAL);
3478 /* [expr.cond]
3480 If the overload resolution fails, the program is
3481 ill-formed. */
3484 {
3488 }
3491 {
3495 }
3497 /* [expr.cond]
3499 Otherwise, the conversions thus determined are applied, and
3500 the converted operands are used in place of the original
3501 operands for the remainder of this section. */
3508 }
3510 /* [expr.cond]
3512 Lvalue-to-rvalue (_conv.lval_), array-to-pointer (_conv.array_),
3513 and function-to-pointer (_conv.func_) standard conversions are
3514 performed on the second and third operands.
3516 We need to force the lvalue-to-rvalue conversion here for class types,
3517 so we get TARGET_EXPRs; trying to deal with a COND_EXPR of class rvalues
3518 that isn't wrapped with a TARGET_EXPR plays havoc with exception
3519 regions. */
3532 /* [expr.cond]
3534 After those conversions, one of the following shall hold:
3536 --The second and third operands have the same type; the result is of
3537 that type. */
3540 /* [expr.cond]
3542 --The second and third operands have arithmetic or enumeration
3543 type; the usual arithmetic conversions are performed to bring
3544 them to a common type, and the result is of that type. */
3549 {
3550 /* In this case, there is always a common type. */
3552 arg3_type);
3567 }
3568 /* [expr.cond]
3570 --The second and third operands have pointer type, or one has
3571 pointer type and the other is a null pointer constant; pointer
3572 conversions (_conv.ptr_) and qualification conversions
3573 (_conv.qual_) are performed to bring them to their composite
3574 pointer type (_expr.rel_). The result is of the composite
3575 pointer type.
3577 --The second and third operands have pointer to member type, or
3578 one has pointer to member type and the other is a null pointer
3579 constant; pointer to member conversions (_conv.mem_) and
3580 qualification conversions (_conv.qual_) are performed to bring
3581 them to a common type, whose cv-qualification shall match the
3582 cv-qualification of either the second or the third operand.
3583 The result is of the common type. */
3591 {
3598 }
3601 {
3605 }
3607 valid_operands:
3610 /* We can't use result_type below, as fold might have returned a
3611 throw_expr. */
3614 {
3615 /* Expand both sides into the same slot, hopefully the target of
3616 the ?: expression. We used to check for TARGET_EXPRs here,
3617 but now we sometimes wrap them in NOP_EXPRs so the test would
3618 fail. */
3621 /* If this expression is an rvalue, but might be mistaken for an
3622 lvalue, we must add a NON_LVALUE_EXPR. */
3624 }
3627 }
3629 /* OPERAND is an operand to an expression. Perform necessary steps
3630 required before using it. If OPERAND is NULL_TREE, NULL_TREE is
3631 returned. */
3633 static tree
3635 {
3637 {
3640 /* Make sure the template type is instantiated now. */
3642 }
3645 }
3647 /* Add each of the viable functions in FNS (a FUNCTION_DECL or
3648 OVERLOAD) to the CANDIDATES, returning an updated list of
3649 CANDIDATES. The ARGS are the arguments provided to the call,
3650 without any implicit object parameter. The EXPLICIT_TARGS are
3651 explicit template arguments provided. TEMPLATE_ONLY is true if
3652 only template functions should be considered. CONVERSION_PATH,
3653 ACCESS_PATH, and FLAGS are as for add_function_candidate. */
3655 static void
3661 {
3662 tree ctype;
3663 tree non_static_args;
3666 /* Delay creating the implicit this parameter until it is needed. */
3670 {
3671 tree fn;
3672 tree fn_args;
3675 /* Figure out which set of arguments to use. */
3677 {
3678 /* If this function is a non-static member, prepend the implicit
3679 object parameter. */
3685 }
3686 else
3687 /* Otherwise, just use the list of arguments provided. */
3692 fn,
3693 ctype,
3694 explicit_targs,
3695 fn_args,
3696 NULL_TREE,
3697 access_path,
3698 conversion_path,
3699 flags,
3700 DEDUCE_CALL);
3703 fn,
3704 ctype,
3705 fn_args,
3706 access_path,
3707 conversion_path,
3708 flags);
3710 }
3711 }
3713 tree
3716 {
3735 {
3739 }
3740 else
3746 {
3751 /* Use build_op_new_call and build_op_delete_call instead. */
3765 }
3771 {
3778 }
3793 /* Get the high-water mark for the CONVERSION_OBSTACK. */
3796 /* Add namespace-scope operators to the list of functions to
3797 consider. */
3801 /* Add class-member operators to the candidate set. */
3803 {
3804 tree fns;
3808 {
3811 }
3818 }
3820 /* Rearrange the arguments for ?: so that add_builtin_candidate only has
3821 to know about two args; a builtin candidate will always have a first
3822 parameter of type bool. We'll handle that in
3823 build_builtin_candidate. */
3825 {
3829 }
3830 else
3831 {
3835 }
3840 {
3843 /* For these, the built-in candidates set is empty
3844 [over.match.oper]/3. We don't want non-strict matches
3845 because exact matches are always possible with built-in
3846 operators. The built-in candidate set for COMPONENT_REF
3847 would be empty too, but since there are no such built-in
3848 operators, we accept non-strict matches for them. */
3855 }
3859 {
3861 {
3864 /* Look for an `operator++ (int)'. If they didn't have
3865 one, then we fall back to the old way of doing things. */
3869 fnname,
3873 else
3876 overloaded_p);
3879 /* The caller will deal with these. */
3889 {
3892 }
3895 }
3896 }
3897 else
3898 {
3901 {
3903 {
3906 }
3908 }
3910 {
3916 else
3918 }
3919 else
3920 {
3921 /* Give any warnings we noticed during overload resolution. */
3923 {
3927 }
3929 /* Check for comparison of different enum types. */
3931 {
3942 {
3945 }
3949 }
3951 /* We need to strip any leading REF_BIND so that bitfields
3952 don't cause errors. This should not remove any important
3953 conversions, because builtins don't apply to class
3954 objects directly. */
3960 {
3965 }
3967 {
3972 }
3975 {
3978 }
3979 }
3980 }
3982 user_defined_result_ready:
3984 /* Free all the conversions we allocated. */
3990 builtin:
3992 {
4046 /* The caller will deal with these. */
4054 }
4056 }
4058 /* Build a call to operator delete. This has to be handled very specially,
4059 because the restrictions on what signatures match are different from all
4060 other call instances. For a normal delete, only a delete taking (void *)
4061 or (void *, size_t) is accepted. For a placement delete, only an exact
4062 match with the placement new is accepted.
4064 CODE is either DELETE_EXPR or VEC_DELETE_EXPR.
4065 ADDR is the pointer to be deleted.
4066 SIZE is the size of the memory block to be deleted.
4067 GLOBAL_P is true if the delete-expression should not consider
4068 class-specific delete operators.
4069 PLACEMENT is the corresponding placement new call, or NULL_TREE.
4071 If this call to "operator delete" is being generated as part to
4072 deallocate memory allocated via a new-expression (as per [expr.new]
4073 which requires that if the initialization throws an exception then
4074 we call a deallocation function), then ALLOC_FN is the allocation
4075 function. */
4077 tree
4080 tree alloc_fn)
4081 {
4096 /* In [class.free]
4098 If the result of the lookup is ambiguous or inaccessible, or if
4099 the lookup selects a placement deallocation function, the
4100 program is ill-formed.
4102 Therefore, we ask lookup_fnfields to complain about ambiguity. */
4103 {
4107 }
4108 else
4114 /* Strip const and volatile from addr. */
4118 {
4119 /* Get the parameter types for the allocation function that is
4120 being called. */
4123 }
4124 else
4125 {
4126 /* First try it without the size argument. */
4128 }
4130 /* We make two tries at finding a matching `operator delete'. On
4131 the first pass, we look for a one-operator (or placement)
4132 operator delete. If we're not doing placement delete, then on
4133 the second pass we look for a two-argument delete. */
4135 {
4136 /* Go through the `operator delete' functions looking for one
4137 with a matching type. */
4139 fn;
4141 {
4142 tree t;
4144 /* The first argument must be "void *". */
4149 /* On the first pass, check the rest of the arguments. */
4151 {
4154 {
4159 }
4162 }
4163 /* On the second pass, look for a function with exactly two
4164 arguments: "void *" and "size_t". */
4166 /* For "operator delete(void *, ...)" there will be
4167 no second argument, but we will not get an exact
4168 match above. */
4169 && t
4173 }
4175 /* If we found a match, we're done. */
4178 }
4180 /* If we have a matching function, call it. */
4182 {
4183 /* Make sure we have the actual function, and not an
4184 OVERLOAD. */
4187 /* If the FN is a member function, make sure that it is
4188 accessible. */
4193 {
4194 /* The placement args might not be suitable for overload
4195 resolution at this point, so build the call directly. */
4204 }
4205 else
4206 {
4207 tree args;
4210 else
4214 }
4215 }
4217 /* [expr.new]
4219 If no unambiguous matching deallocation function can be found,
4220 propagating the exception does not cause the object's memory to
4221 be freed. */
4223 {
4226 alloc_fn);
4228 }
4233 }
4235 /* If the current scope isn't allowed to access DECL along
4236 BASETYPE_PATH, give an error. The most derived class in
4237 BASETYPE_PATH is the one used to qualify DECL. DIAG_DECL is
4238 the declaration to use in the error diagnostic. */
4240 bool
4242 {
4246 {
4251 else
4255 }
4258 }
4260 /* Initialize a temporary of type TYPE with EXPR. The FLAGS are a
4261 bitwise or of LOOKUP_* values. If any errors are warnings are
4262 generated, set *DIAGNOSTIC_FN to "error" or "warning",
4263 respectively. If no diagnostics are generated, set *DIAGNOSTIC_FN
4264 to NULL. */
4266 static tree
4269 {
4274 complete_ctor_identifier,
4281 else
4284 }
4286 /* Perform warnings about peculiar, but valid, conversions from/to NULL.
4287 EXPR is implicitly converted to type TOTYPE.
4288 FN and ARGNUM are used for diagnostics. */
4290 static void
4292 {
4295 /* Issue warnings about peculiar, but valid, uses of NULL. */
4297 {
4301 else
4303 }
4305 /* Issue warnings if "false" is converted to a NULL pointer */
4310 }
4312 /* Perform the conversions in CONVS on the expression EXPR. FN and
4313 ARGNUM are used for diagnostics. ARGNUM is zero based, -1
4314 indicates the `this' argument of a method. INNER is nonzero when
4315 being called to continue a conversion chain. It is negative when a
4316 reference binding will be applied, positive otherwise. If
4317 ISSUE_CONVERSION_WARNINGS is true, warnings about suspicious
4318 conversions will be emitted if appropriate. If C_CAST_P is true,
4319 this conversion is coming from a C-style cast; in that case,
4320 conversions to inaccessible bases are permitted. */
4322 static tree
4326 {
4328 diagnostic_fn_t diagnostic_fn;
4334 {
4337 {
4339 {
4344 }
4351 }
4356 }
4362 {
4364 {
4370 /* If this is a constructor or a function returning an aggr type,
4371 we need to build up a TARGET_EXPR. */
4375 /* The result of the call is then used to direct-initialize the object
4376 that is the destination of the copy-initialization. [dcl.init]
4378 Note that this step is not reflected in the conversion sequence;
4379 it affects the semantics when we actually perform the
4380 conversion, but is not considered during overload resolution.
4382 If the target is a class, that means call a ctor. */
4385 {
4386 expr = (build_temp
4388 /* Core issue 84, now a DR, says that we don't
4389 allow UDCs for these args (which deliberately
4390 breaks copy-init of an auto_ptr<Base> from an
4391 auto_ptr<Derived>). */
4396 {
4398 diagnostic_fn
4401 else
4402 diagnostic_fn
4404 }
4406 }
4408 }
4412 /* Convert a constant to its underlying value, unless we are
4413 about to bind it to a reference, in which case we need to
4414 leave it as an lvalue. */
4416 {
4419 /* If __null has been converted to an integer type, we do not
4420 want to warn about uses of EXPR as an integer, rather than
4421 as a pointer. */
4423 }
4426 /* Call build_user_type_conversion again for the error. */
4427 return build_user_type_conversion
4432 };
4437 c_cast_p);
4442 {
4447 /* Else fall through. */
4450 {
4451 /* We are going to bind a reference directly to a base-class
4452 subobject of EXPR. */
4453 /* Build an expression for `*((base*) &expr)'. */
4459 }
4461 /* Copy-initialization where the cv-unqualified version of the source
4462 type is the same class as, or a derived class of, the class of the
4463 destination [is treated as direct-initialization]. [dcl.init] */
4471 {
4474 /* If necessary, create a temporary.
4476 VA_ARG_EXPR and CONSTRUCTOR expressions are special cases
4477 that need temporaries, even when their types are reference
4478 compatible with the type of reference being bound, so the
4479 upcoming call to build_unary_op (ADDR_EXPR, expr, ...)
4480 doesn't fail. */
4484 {
4490 {
4491 /* If the reference is volatile or non-const, we
4492 cannot create a temporary. */
4499 else
4502 }
4503 /* If the source is a packed field, and we must use a copy
4504 constructor, then building the target expr will require
4505 binding the field to the reference parameter to the
4506 copy constructor, and we'll end up with an infinite
4507 loop. If we can use a bitwise copy, then we'll be
4508 OK. */
4512 {
4516 }
4518 }
4520 /* Take the address of the thing to which we will bind the
4521 reference. */
4526 /* Convert it to a pointer to the type referred to by the
4527 reference. This will adjust the pointer if a derived to
4528 base conversion is being performed. */
4530 expr);
4531 /* Convert the pointer to the desired reference type. */
4533 }
4539 /* Warn about deprecated conversion if appropriate. */
4551 c_cast_p);
4555 }
4559 else
4563 }
4565 /* Build a call to __builtin_trap. */
4567 static tree
4569 {
4575 }
4577 /* ARG is being passed to a varargs function. Perform any conversions
4578 required. Return the converted value. */
4580 tree
4582 {
4583 /* [expr.call]
4585 The lvalue-to-rvalue, array-to-pointer, and function-to-pointer
4586 standard conversions are performed. */
4588 /* [expr.call]
4590 If the argument has integral or enumeration type that is subject
4591 to the integral promotions (_conv.prom_), or a floating point
4592 type that is subject to the floating point promotion
4593 (_conv.fpprom_), the value of the argument is converted to the
4594 promoted type before the call. */
4606 {
4607 /* Undefined behavior [expr.call] 5.2.2/7. We used to just warn
4608 here and do a bitwise copy, but now cp_expr_size will abort if we
4609 try to do that.
4610 If the call appears in the context of a sizeof expression,
4611 there is no need to emit a warning, since the expression won't be
4612 evaluated. We keep the builtin_trap just as a safety check. */
4618 integer_zero_node);
4619 }
4622 }
4624 /* va_arg (EXPR, TYPE) is a builtin. Make sure it is not abused. */
4626 tree
4628 {
4638 {
4639 /* Remove reference types so we don't ICE later on. */
4641 /* Undefined behavior [expr.call] 5.2.2/7. */
4649 }
4652 }
4654 /* TYPE has been given to va_arg. Apply the default conversions which
4655 would have happened when passed via ellipsis. Return the promoted
4656 type, or the passed type if there is no change. */
4658 tree
4660 {
4661 tree promote;
4663 /* Perform the array-to-pointer and function-to-pointer
4664 conversions. */
4672 }
4674 /* ARG is a default argument expression being passed to a parameter of
4675 the indicated TYPE, which is a parameter to FN. Do any required
4676 conversions. Return the converted value. */
4680 tree
4682 {
4684 tree t;
4686 /* If the ARG is an unparsed default argument expression, the
4687 conversion cannot be performed. */
4689 {
4694 }
4696 /* Detect recursion. */
4699 {
4702 }
4711 {
4715 }
4716 else
4717 {
4718 /* We must make a copy of ARG, in case subsequent processing
4719 alters any part of it. For example, during gimplification a
4720 cast of the form (T) &X::f (where "f" is a member function)
4721 will lead to replacing the PTRMEM_CST for &X::f with a
4722 VAR_DECL. We can avoid the copy for constants, since they
4723 are never modified in place. */
4729 }
4734 }
4736 /* Returns the type which will really be used for passing an argument of
4737 type TYPE. */
4739 tree
4741 {
4742 /* Pass classes with copy ctors by invisible reference. */
4744 {
4746 /* There are no other pointers to this temporary. */
4748 }
4757 }
4759 /* Actually perform the appropriate conversion. */
4761 tree
4763 {
4764 tree bitfield_type;
4766 /* If VAL is a bitfield, then -- since it has already been converted
4767 to TYPE -- it cannot have a precision greater than TYPE.
4769 If it has a smaller precision, we must widen it here. For
4770 example, passing "int f:3;" to a function expecting an "int" will
4771 not result in any conversion before this point.
4773 If the precision is the same we must not risk widening. For
4774 example, the COMPONENT_REF for a 32-bit "long long" bitfield will
4775 often have type "int", even though the C++ type for the field is
4776 "long long". If the value is being passed to a function
4777 expecting an "int", then no conversions will be required. But,
4778 if we call convert_bitfield_to_declared_type, the bitfield will
4779 be converted to "long long". */
4786 ;
4787 /* Pass classes with copy ctors by invisible reference. */
4797 {
4806 }
4808 }
4810 /* Returns true iff FN is a function with magic varargs, i.e. ones for
4811 which no conversions at all should be done. This is true for some
4812 builtins which don't act like normal functions. */
4814 static bool
4816 {
4819 {
4830 }
4833 }
4835 /* Subroutine of the various build_*_call functions. Overload resolution
4836 has chosen a winning candidate CAND; build up a CALL_EXPR accordingly.
4837 ARGS is a TREE_LIST of the unconverted arguments to the call. FLAGS is a
4838 bitmask of various LOOKUP_* flags which apply to the call itself. */
4840 static tree
4842 {
4856 /* In a template, there is no need to perform all of the work that
4857 is normally done. We are only interested in the type of the call
4858 expression, i.e., the return type of the function. Any semantic
4859 errors will be deferred until the template is instantiated. */
4861 {
4862 tree expr;
4863 tree return_type;
4871 }
4873 /* Give any warnings we noticed during overload resolution. */
4875 {
4879 }
4882 {
4883 /* If FN is a template function, two cases must be considered.
4884 For example:
4886 struct A {
4887 protected:
4888 template <class T> void f();
4889 };
4890 template <class T> struct B {
4891 protected:
4892 void g();
4893 };
4894 struct C : A, B<int> {
4895 using A::f; // #1
4896 using B<int>::g; // #2
4897 };
4899 In case #1 where `A::f' is a member template, DECL_ACCESS is
4900 recorded in the primary template but not in its specialization.
4901 We check access of FN using its primary template.
4903 In case #2, where `B<int>::g' has a DECL_TEMPLATE_INFO simply
4904 because it is a member of class template B, DECL_ACCESS is
4905 recorded in the specialization `B<int>::g'. We cannot use its
4906 primary template because `B<T>::g' and `B<int>::g' may have
4907 different access. */
4912 else
4914 }
4920 /* Find maximum size of vector to hold converted arguments. */
4927 /* The implicit parameters to a constructor are not considered by overload
4928 resolution, and must be of the proper type. */
4930 {
4934 /* We should never try to call the abstract constructor. */
4938 {
4942 }
4943 }
4944 /* Bypass access control for 'this' parameter. */
4946 {
4949 tree converted_arg;
4950 tree base_binfo;
4956 /* [class.mfct.nonstatic]: If a nonstatic member function of a class
4957 X is called for an object that is not of type X, or of a type
4958 derived from X, the behavior is undefined.
4960 So we can assume that anything passed as 'this' is non-null, and
4961 optimize accordingly. */
4963 /* Convert to the base in which the function was declared. */
4969 /* Check that the base class is accessible. */
4975 /* If fn was found by a using declaration, the conversion path
4976 will be to the derived class, not the base declaring fn. We
4977 must convert from derived to base. */
4988 }
4992 {
4997 /* Don't make a copy here if build_call is going to. */
5003 val = convert_like_with_context
5008 }
5010 /* Default arguments */
5015 /* Ellipsis */
5017 {
5021 else
5024 }
5032 /* Avoid actually calling copy constructors and copy assignment operators,
5033 if possible. */
5040 {
5041 tree targ;
5044 /* Pull out the real argument, disregarding const-correctness. */
5051 {
5056 }
5057 else
5062 else
5065 /* [class.copy]: the copy constructor is implicitly defined even if
5066 the implementation elided its use. */
5070 /* If we're creating a temp and we already have one, don't create a
5071 new one. If we're not creating a temp but we get one, use
5072 INIT_EXPR to collapse the temp into our target. Otherwise, if the
5073 ctor is trivial, do a bitwise copy with a simple TARGET_EXPR for a
5074 temp or an INIT_EXPR otherwise. */
5076 {
5081 }
5085 {
5086 tree to = stabilize_reference
5091 }
5092 }
5096 {
5097 tree to = stabilize_reference
5104 {
5107 }
5108 else
5109 {
5110 /* We must only copy the non-tail padding parts.
5111 Use __builtin_memcpy for the bitwise copy. */
5123 }
5126 }
5131 {
5132 tree t;
5138 /* Warn about deprecated virtual functions now, since we're about
5139 to throw away the decl. */
5149 else
5152 }
5155 else
5159 }
5161 /* Build and return a call to FN, using NARGS arguments in ARGARRAY.
5162 This function performs no overload resolution, conversion, or other
5163 high-level operations. */
5165 tree
5167 {
5168 tree fndecl;
5172 /* If this call might throw an exception, note that fact. */
5179 /* Some built-in function calls will be evaluated at compile-time in
5180 fold (). */
5193 }
5197 /* Make an expression which yields the address of the Java interface
5198 method FN. This is achieved by generating a call to libjava's
5199 _Jv_LookupInterfaceMethodIdx(). */
5201 static tree
5203 {
5209 {
5214 endlink)));
5215 java_iface_lookup_fn
5219 }
5221 /* Look up the pointer to the runtime java.lang.Class object for `instance'.
5222 This is the first entry in the vtable. */
5224 integer_zero_node);
5226 /* Get the java.lang.Class pointer for the interface being called. */
5231 {
5233 iface);
5235 }
5239 /* Determine the itable index of FN. */
5242 {
5247 i++;
5248 }
5253 java_iface_lookup_fn);
5256 }
5258 /* Returns the value to use for the in-charge parameter when making a
5259 call to a function with the indicated NAME.
5261 FIXME:Can't we find a neater way to do this mapping? */
5263 tree
5265 {
5276 /* This function should only be called with one of the names listed
5277 above. */
5280 }
5282 /* Build a call to a constructor, destructor, or an assignment
5283 operator for INSTANCE, an expression with class type. NAME
5284 indicates the special member function to call; ARGS are the
5285 arguments. BINFO indicates the base of INSTANCE that is to be
5286 passed as the `this' parameter to the member function called.
5288 FLAGS are the LOOKUP_* flags to use when processing the call.
5290 If NAME indicates a complete object constructor, INSTANCE may be
5291 NULL_TREE. In this case, the caller will call build_cplus_new to
5292 store the newly constructed object into a VAR_DECL. */
5294 tree
5297 {
5298 tree fns;
5299 /* The type of the subobject to be constructed or destroyed. */
5300 tree class_type;
5309 {
5310 /* Resolve the name. */
5315 }
5321 /* Handle the special case where INSTANCE is NULL_TREE. */
5323 {
5326 }
5327 else
5328 {
5334 /* Convert to the base class, if necessary. */
5337 {
5339 /* For constructors and destructors, either the base is
5340 non-virtual, or it is virtual but we are doing the
5341 conversion from a constructor or destructor for the
5342 complete object. In either case, we can convert
5343 statically. */
5345 else
5346 /* However, for assignment operators, we must convert
5347 dynamically if the base is virtual. */
5350 }
5351 }
5357 /* When making a call to a constructor or destructor for a subobject
5358 that uses virtual base classes, pass down a pointer to a VTT for
5359 the subobject. */
5363 {
5364 tree vtt;
5365 tree sub_vtt;
5367 /* If the current function is a complete object constructor
5368 or destructor, then we fetch the VTT directly.
5369 Otherwise, we look it up using the VTT we were given. */
5375 current_vtt_parm,
5376 vtt);
5382 }
5387 }
5389 /* Return the NAME, as a C string. The NAME indicates a function that
5390 is a member of TYPE. *FREE_P is set to true if the caller must
5391 free the memory returned.
5393 Rather than go through all of this, we should simply set the names
5394 of constructors and destructors appropriately, and dispense with
5395 ctor_identifier, dtor_identifier, etc. */
5399 {
5402 /* Assume that we will not allocate memory. */
5404 /* Constructors and destructors are special. */
5406 {
5407 pretty_name
5409 /* For a destructor, add the '~'. */
5413 {
5415 /* Remember that we need to free the memory allocated. */
5417 }
5418 }
5420 {
5423 TFF_PLAIN_IDENTIFIER),
5424 NULL);
5425 /* Remember that we need to free the memory allocated. */
5427 }
5428 else
5432 }
5434 /* Build a call to "INSTANCE.FN (ARGS)". If FN_P is non-NULL, it will
5435 be set, upon return, to the function called. */
5437 tree
5441 {
5445 tree access_binfo;
5446 tree optype;
5448 tree name;
5449 tree user_args;
5450 tree call;
5451 tree fn;
5452 tree class_type;
5455 tree orig_instance;
5456 tree orig_fns;
5457 tree orig_args;
5462 /* We don't know what function we're going to call, yet. */
5472 {
5475 }
5481 /* Dismantle the baselink to collect all the information we need. */
5488 {
5492 }
5503 {
5506 }
5508 /* The USER_ARGS are the arguments we will display to users if an
5509 error occurs. The USER_ARGS should not include any
5510 compiler-generated arguments. The "this" pointer hasn't been
5511 added yet. However, we must remove the VTT pointer if this is a
5512 call to a base-class constructor or destructor. */
5515 {
5516 /* Callers should explicitly indicate whether they want to construct
5517 the complete object or just the part without virtual bases. */
5519 /* Similarly for destructors. */
5521 /* Remove the VTT pointer, if present. */
5525 }
5527 /* Process the argument list. */
5534 /* It's OK to call destructors and constructors on cv-qualified objects.
5535 Therefore, convert the INSTANCE_PTR to the unqualified type, if
5536 necessary. */
5539 {
5543 }
5550 /* Get the high-water mark for the CONVERSION_OBSTACK. */
5554 {
5556 tree this_arglist;
5558 /* We can end up here for copy-init of same or base class. */
5565 else
5569 /* A member template. */
5571 class_type,
5572 explicit_targs,
5574 access_binfo,
5575 conversion_path,
5576 flags,
5577 DEDUCE_CALL);
5580 class_type,
5581 this_arglist,
5582 access_binfo,
5583 conversion_path,
5584 flags);
5585 }
5589 {
5592 else
5593 {
5603 }
5606 }
5607 else
5608 {
5611 {
5617 user_args);
5622 }
5623 else
5624 {
5632 /* This is not an error, it is runtime undefined
5633 behavior. */
5635 "abstract virtual %q#D called from constructor"
5637 fn);
5641 {
5643 fn);
5645 }
5646 else
5647 {
5651 /* Now we know what function is being called. */
5654 /* Build the actual CALL_EXPR. */
5656 /* In an expression of the form `a->f()' where `f' turns
5657 out to be a static member function, `a' is
5658 none-the-less evaluated. */
5667 /* An explicit call of the form "x->~X()" has type
5668 "void". However, on platforms where destructors
5669 return "this" (i.e., those where
5670 targetm.cxx.cdtor_returns_this is true), such calls
5671 will appear to have a return value of pointer type
5672 to the low-level call machinery. We do not want to
5673 change the low-level machinery, since we want to be
5674 able to optimize "delete f()" on such platforms as
5675 "operator delete(~X(f()))" (rather than generating
5676 "t = f(), ~X(t), operator delete (t)"). */
5678 }
5679 }
5680 }
5683 call = (build_min_non_dep_call_list
5686 orig_args));
5688 /* Free all the conversions we allocated. */
5692 }
5694 /* Returns true iff standard conversion sequence ICS1 is a proper
5695 subsequence of ICS2. */
5697 static bool
5699 {
5700 /* We can assume that a conversion of the same code
5701 between the same types indicates a subsequence since we only get
5702 here if the types we are converting from are the same. */
5709 {
5717 /* At this point, ICS1 cannot be a proper subsequence of
5718 ICS2. We can get a USER_CONV when we are comparing the
5719 second standard conversion sequence of two user conversion
5720 sequences. */
5730 }
5731 }
5733 /* Returns nonzero iff DERIVED is derived from BASE. The inputs may
5734 be any _TYPE nodes. */
5736 bool
5738 {
5743 /* We only allow proper derivation here. The DERIVED_FROM_P macro
5744 considers every class derived from itself. */
5747 }
5749 /* We build the ICS for an implicit object parameter as a pointer
5750 conversion sequence. However, such a sequence should be compared
5751 as if it were a reference conversion sequence. If ICS is the
5752 implicit conversion sequence for an implicit object parameter,
5753 modify it accordingly. */
5755 static void
5757 {
5759 {
5760 /* [over.match.funcs]
5762 For non-static member functions, the type of the
5763 implicit object parameter is "reference to cv X"
5764 where X is the class of which the function is a
5765 member and cv is the cv-qualification on the member
5766 function declaration. */
5768 tree reference_type;
5770 /* The `this' parameter is a pointer to a class type. Make the
5771 implicit conversion talk about a reference to that same class
5772 type. */
5785 }
5786 }
5788 /* If *ICS is a REF_BIND set *ICS to the remainder of the conversion,
5789 and return the initial reference binding conversion. Otherwise,
5790 leave *ICS unchanged and return NULL. */
5794 {
5796 {
5802 }
5805 }
5807 /* Compare two implicit conversion sequences according to the rules set out in
5808 [over.ics.rank]. Return values:
5810 1: ics1 is better than ics2
5811 -1: ics2 is better than ics1
5812 0: ics1 and ics2 are indistinguishable */
5814 static int
5816 {
5817 tree from_type1;
5818 tree from_type2;
5819 tree to_type1;
5820 tree to_type2;
5827 /* REF_BINDING is nonzero if the result of the conversion sequence
5828 is a reference type. In that case REF_CONV is the reference
5829 binding conversion. */
5833 /* Handle implicit object parameters. */
5837 /* Handle reference parameters. */
5841 /* [over.ics.rank]
5843 When comparing the basic forms of implicit conversion sequences (as
5844 defined in _over.best.ics_)
5846 --a standard conversion sequence (_over.ics.scs_) is a better
5847 conversion sequence than a user-defined conversion sequence
5848 or an ellipsis conversion sequence, and
5850 --a user-defined conversion sequence (_over.ics.user_) is a
5851 better conversion sequence than an ellipsis conversion sequence
5852 (_over.ics.ellipsis_). */
5862 {
5863 /* XXX Isn't this an extension? */
5864 /* Both ICS are bad. We try to make a decision based on what
5865 would have happened if they'd been good. */
5873 /* We couldn't make up our minds; try to figure it out below. */
5874 }
5877 /* Both conversions are ellipsis conversions. */
5880 /* User-defined conversion sequence U1 is a better conversion sequence
5881 than another user-defined conversion sequence U2 if they contain the
5882 same user-defined conversion operator or constructor and if the sec-
5883 ond standard conversion sequence of U1 is better than the second
5884 standard conversion sequence of U2. */
5887 {
5901 /* We can just fall through here, after setting up
5902 FROM_TYPE1 and FROM_TYPE2. */
5905 }
5906 else
5907 {
5911 /* We're dealing with two standard conversion sequences.
5913 [over.ics.rank]
5915 Standard conversion sequence S1 is a better conversion
5916 sequence than standard conversion sequence S2 if
5918 --S1 is a proper subsequence of S2 (comparing the conversion
5919 sequences in the canonical form defined by _over.ics.scs_,
5920 excluding any Lvalue Transformation; the identity
5921 conversion sequence is considered to be a subsequence of
5922 any non-identity conversion sequence */
5933 }
5936 {
5941 }
5942 /* Otherwise, one sequence cannot be a subsequence of the other; they
5943 don't start with the same type. This can happen when comparing the
5944 second standard conversion sequence in two user-defined conversion
5945 sequences. */
5947 /* [over.ics.rank]
5949 Or, if not that,
5951 --the rank of S1 is better than the rank of S2 (by the rules
5952 defined below):
5954 Standard conversion sequences are ordered by their ranks: an Exact
5955 Match is a better conversion than a Promotion, which is a better
5956 conversion than a Conversion.
5958 Two conversion sequences with the same rank are indistinguishable
5959 unless one of the following rules applies:
5961 --A conversion that is not a conversion of a pointer, or pointer
5962 to member, to bool is better than another conversion that is such
5963 a conversion.
5965 The ICS_STD_RANK automatically handles the pointer-to-bool rule,
5966 so that we do not have to check it explicitly. */
5979 {
5984 }
5985 /* The rules for pointers to members A::* are just like the rules
5986 for pointers A*, except opposite: if B is derived from A then
5987 A::* converts to B::*, not vice versa. For that reason, we
5988 switch the from_ and to_ variables here. */
5995 {
6000 }
6005 {
6006 /* This was one of the pointer or pointer-like conversions.
6008 [over.ics.rank]
6010 --If class B is derived directly or indirectly from class A,
6011 conversion of B* to A* is better than conversion of B* to
6012 void*, and conversion of A* to void* is better than
6013 conversion of B* to void*. */
6016 {
6018 deref_from_type2))
6021 deref_from_type1))
6023 }
6026 {
6028 {
6030 {
6032 deref_to_type1))
6034 }
6035 /* We know that DEREF_TO_TYPE1 is `void' here. */
6037 deref_to_type2))
6039 }
6040 }
6043 {
6044 /* [over.ics.rank]
6046 --If class B is derived directly or indirectly from class A
6047 and class C is derived directly or indirectly from B,
6049 --conversion of C* to B* is better than conversion of C* to
6050 A*,
6052 --conversion of B* to A* is better than conversion of C* to
6053 A* */
6055 {
6057 deref_to_type2))
6060 deref_to_type1))
6062 }
6064 {
6066 deref_from_type1))
6069 deref_from_type2))
6071 }
6072 }
6073 }
6076 {
6079 /* [over.ics.rank]
6081 --binding of an expression of type C to a reference of type
6082 B& is better than binding an expression of type C to a
6083 reference of type A&
6085 --conversion of C to B is better than conversion of C to A, */
6088 {
6093 }
6094 }
6097 {
6100 /* [over.ics.rank]
6102 --binding of an expression of type B to a reference of type
6103 A& is better than binding an expression of type C to a
6104 reference of type A&,
6106 --conversion of B to A is better than conversion of C to A */
6109 {
6114 }
6115 }
6117 /* [over.ics.rank]
6119 --S1 and S2 differ only in their qualification conversion and yield
6120 similar types T1 and T2 (_conv.qual_), respectively, and the cv-
6121 qualification signature of type T1 is a proper subset of the cv-
6122 qualification signature of type T2 */
6126 {
6130 }
6132 /* [over.ics.rank]
6134 --S1 and S2 are reference bindings (_dcl.init.ref_) and neither refers
6135 to an implicit object parameter, and either S1 binds an lvalue reference
6136 to an lvalue and S2 binds an rvalue reference or S1 binds an rvalue
6137 reference to an rvalue and S2 binds an lvalue reference
6138 (C++0x draft standard, 13.3.3.2)
6140 --S1 and S2 are reference bindings (_dcl.init.ref_), and the
6141 types to which the references refer are the same type except for
6142 top-level cv-qualifiers, and the type to which the reference
6143 initialized by S2 refers is more cv-qualified than the type to
6144 which the reference initialized by S1 refers */
6147 {
6151 {
6156 }
6161 }
6163 /* Neither conversion sequence is better than the other. */
6165 }
6167 /* The source type for this standard conversion sequence. */
6169 static tree
6171 {
6173 {
6178 }
6180 }
6182 /* Note a warning about preferring WINNER to LOSER. We do this by storing
6183 a pointer to LOSER and re-running joust to produce the warning if WINNER
6184 is actually used. */
6186 static void
6188 {
6194 }
6196 /* Compare two candidates for overloading as described in
6197 [over.match.best]. Return values:
6199 1: cand1 is better than cand2
6200 -1: cand2 is better than cand1
6201 0: cand1 and cand2 are indistinguishable */
6203 static int
6205 {
6211 /* Candidates that involve bad conversions are always worse than those
6212 that don't. */
6218 /* If we have two pseudo-candidates for conversions to the same type,
6219 or two candidates for the same function, arbitrarily pick one. */
6224 /* a viable function F1
6225 is defined to be a better function than another viable function F2 if
6226 for all arguments i, ICSi(F1) is not a worse conversion sequence than
6227 ICSi(F2), and then */
6229 /* for some argument j, ICSj(F1) is a better conversion sequence than
6230 ICSj(F2) */
6232 /* For comparing static and non-static member functions, we ignore
6233 the implicit object parameter of the non-static function. The
6234 standard says to pretend that the static function has an object
6235 parm, but that won't work with operator overloading. */
6238 {
6246 else
6247 {
6250 }
6251 }
6254 {
6260 {
6273 {
6280 else
6285 {
6289 }
6290 else
6292 }
6295 {
6298 }
6300 }
6301 }
6303 /* warn about confusing overload resolution for user-defined conversions,
6304 either between a constructor and a conversion op, or between two
6305 conversion ops. */
6309 {
6315 else
6318 /* We don't want to complain about `X::operator T1 ()'
6319 beating `X::operator T2 () const', when T2 is a no less
6320 cv-qualified version of T1. */
6323 {
6328 {
6331 }
6334 }
6335 else
6341 {
6349 }
6350 else
6352 }
6357 /* or, if not that,
6358 F1 is a non-template function and F2 is a template function
6359 specialization. */
6366 /* or, if not that,
6367 F1 and F2 are template functions and the function template for F1 is
6368 more specialized than the template for F2 according to the partial
6369 ordering rules. */
6372 {
6373 winner = more_specialized_fn
6376 /* [temp.func.order]: The presence of unused ellipsis and default
6377 arguments has no effect on the partial ordering of function
6378 templates. add_function_candidate() will not have
6379 counted the "this" argument for constructors. */
6383 }
6385 /* or, if not that,
6386 the context is an initialization by user-defined conversion (see
6387 _dcl.init_ and _over.match.user_) and the standard conversion
6388 sequence from the return type of F1 to the destination type (i.e.,
6389 the type of the entity being initialized) is a better conversion
6390 sequence than the standard conversion sequence from the return type
6391 of F2 to the destination type. */
6394 {
6398 }
6400 /* Check whether we can discard a builtin candidate, either because we
6401 have two identical ones or matching builtin and non-builtin candidates.
6403 (Pedantically in the latter case the builtin which matched the user
6404 function should not be added to the overload set, but we spot it here.
6406 [over.match.oper]
6407 ... the builtin candidates include ...
6408 - do not have the same parameter type list as any non-template
6409 non-member candidate. */
6413 {
6419 {
6421 /* Two built-in candidates; arbitrarily pick one. */
6424 /* cand1 is built-in; prefer cand2. */
6426 else
6427 /* cand2 is built-in; prefer cand1. */
6429 }
6430 }
6432 /* If the two functions are the same (this can happen with declarations
6433 in multiple scopes and arg-dependent lookup), arbitrarily choose one. */
6438 tweak:
6440 /* Extension: If the worst conversion for one candidate is worse than the
6441 worst conversion for the other, take the first. */
6443 {
6448 {
6453 }
6459 {
6461 {
6463 ISO C++ says that these are ambiguous, even \
6464 though the worst conversion for the first is better than \
6468 }
6469 else
6472 }
6473 }
6477 }
6479 /* Given a list of candidates for overloading, find the best one, if any.
6480 This algorithm has a worst case of O(2n) (winner is last), and a best
6481 case of O(n/2) (totally ambiguous); much better than a sorting
6482 algorithm. */
6486 {
6491 /* Walk through the list once, comparing each current champ to the next
6492 candidate, knocking out a candidate or two with each comparison. */
6495 {
6499 else
6500 {
6502 {
6507 }
6508 else
6509 {
6512 }
6515 }
6516 }
6518 /* Make sure the champ is better than all the candidates it hasn't yet
6519 been compared to. */
6522 challenger != champ
6525 {
6529 }
6532 }
6534 /* Returns nonzero if things of type FROM can be converted to TO. */
6536 bool
6538 {
6540 }
6542 /* Returns nonzero if ARG (of type FROM) can be converted to TO. */
6544 bool
6546 {
6551 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6555 flags);
6558 /* Free all the conversions we allocated. */
6562 }
6564 /* Like can_convert_arg, but allows dubious conversions as well. */
6566 bool
6568 {
6572 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6574 /* Try to perform the conversion. */
6576 LOOKUP_NORMAL);
6577 /* Free all the conversions we allocated. */
6581 }
6583 /* Convert EXPR to TYPE. Return the converted expression.
6585 Note that we allow bad conversions here because by the time we get to
6586 this point we are committed to doing the conversion. If we end up
6587 doing a bad conversion, convert_like will complain. */
6589 tree
6591 {
6598 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6603 LOOKUP_NORMAL);
6605 {
6608 }
6610 {
6611 /* In a template, we are only concerned about determining the
6612 type of non-dependent expressions, so we do not have to
6613 perform the actual conversion. */
6616 }
6617 else
6620 /* Free all the conversions we allocated. */
6624 }
6626 /* Convert EXPR to TYPE (as a direct-initialization) if that is
6627 permitted. If the conversion is valid, the converted expression is
6628 returned. Otherwise, NULL_TREE is returned, except in the case
6629 that TYPE is a class type; in that case, an error is issued. If
6630 C_CAST_P is true, then this direction initialization is taking
6631 place as part of a static_cast being attempted as part of a C-style
6632 cast. */
6634 tree
6636 tree expr,
6638 {
6644 /* [dcl.init]
6646 If the destination type is a (possibly cv-qualified) class type:
6648 -- If the initialization is direct-initialization ...,
6649 constructors are considered. ... If no constructor applies, or
6650 the overload resolution is ambiguous, the initialization is
6651 ill-formed. */
6653 {
6658 }
6660 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6664 c_cast_p,
6665 LOOKUP_NORMAL);
6668 else
6671 c_cast_p);
6673 /* Free all the conversions we allocated. */
6677 }
6679 /* DECL is a VAR_DECL whose type is a REFERENCE_TYPE. The reference
6680 is being bound to a temporary. Create and return a new VAR_DECL
6681 with the indicated TYPE; this variable will store the value to
6682 which the reference is bound. */
6684 tree
6686 {
6687 tree var;
6689 /* Create the variable. */
6692 /* Register the variable. */
6694 {
6695 /* Namespace-scope or local static; give it a mangled name. */
6696 tree name;
6703 }
6704 else
6705 /* Create a new cleanup level if necessary. */
6709 }
6711 /* Convert EXPR to the indicated reference TYPE, in a way suitable for
6712 initializing a variable of that TYPE. If DECL is non-NULL, it is
6713 the VAR_DECL being initialized with the EXPR. (In that case, the
6714 type of DECL will be TYPE.) If DECL is non-NULL, then CLEANUP must
6715 also be non-NULL, and with *CLEANUP initialized to NULL. Upon
6716 return, if *CLEANUP is no longer NULL, it will be an expression
6717 that should be pushed as a cleanup after the returned expression
6718 is used to initialize DECL.
6720 Return the converted expression. */
6722 tree
6724 {
6731 /* Get the high-water mark for the CONVERSION_OBSTACK. */
6735 LOOKUP_NORMAL);
6737 {
6743 else
6748 }
6750 /* If DECL is non-NULL, then this special rule applies:
6752 [class.temporary]
6754 The temporary to which the reference is bound or the temporary
6755 that is the complete object to which the reference is bound
6756 persists for the lifetime of the reference.
6758 The temporaries created during the evaluation of the expression
6759 initializing the reference, except the temporary to which the
6760 reference is bound, are destroyed at the end of the
6761 full-expression in which they are created.
6763 In that case, we store the converted expression into a new
6764 VAR_DECL in a new scope.
6766 However, we want to be careful not to create temporaries when
6767 they are not required. For example, given:
6769 struct B {};
6770 struct D : public B {};
6771 D f();
6772 const B& b = f();
6774 there is no need to copy the return value from "f"; we can just
6775 extend its lifetime. Similarly, given:
6777 struct S {};
6778 struct T { operator S(); };
6779 T t;
6780 const S& s = t;
6782 we can extend the lifetime of the return value of the conversion
6783 operator. */
6786 {
6787 tree var;
6788 tree base_conv_type;
6790 /* Skip over the REF_BIND. */
6792 /* If the next conversion is a BASE_CONV, skip that too -- but
6793 remember that the conversion was required. */
6795 {
6798 }
6799 else
6801 /* Perform the remainder of the conversion. */
6809 else
6810 {
6812 {
6813 tree init;
6814 tree type;
6816 /* Create the temporary variable. */
6820 /* If the rvalue is the result of a function call it will be
6821 a TARGET_EXPR. If it is some other construct (such as a
6822 member access expression where the underlying object is
6823 itself the result of a function call), turn it into a
6824 TARGET_EXPR here. It is important that EXPR be a
6825 TARGET_EXPR below since otherwise the INIT_EXPR will
6826 attempt to make a bitwise copy of EXPR to initialize
6827 VAR. */
6830 /* Create the INIT_EXPR that will initialize the temporary
6831 variable. */
6834 {
6839 else
6842 /* We must be careful to destroy the temporary only
6843 after its initialization has taken place. If the
6844 initialization throws an exception, then the
6845 destructor should not be run. We cannot simply
6846 transform INIT into something like:
6848 (INIT, ({ CLEANUP_STMT; }))
6850 because emit_local_var always treats the
6851 initializer as a full-expression. Thus, the
6852 destructor would run too early; it would run at the
6853 end of initializing the reference variable, rather
6854 than at the end of the block enclosing the
6855 reference variable.
6857 The solution is to pass back a cleanup expression
6858 which the caller is responsible for attaching to
6859 the statement tree. */
6860 }
6861 else
6862 {
6866 static_aggregates);
6867 }
6868 /* Use its address to initialize the reference variable. */
6876 }
6877 else
6878 /* Take the address of EXPR. */
6880 /* If a BASE_CONV was required, perform it now. */
6882 expr = (perform_implicit_conversion
6885 }
6886 }
6887 else
6888 /* Perform the conversion. */
6891 /* Free all the conversions we allocated. */
6895 }