| blob | ec32c5a05426d0a6f7f5c3d15566990883268b31 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2015 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
51 /* The type of functions taking a tree, and some additional data, and
52 returning an int. */
55 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
56 instantiations have been deferred, either because their definitions
57 were not yet available, or because we were putting off doing the work. */
61 };
76 /* Live only within one (recursive) call to tsubst_expr. We use
77 this to pass the statement expression node from the STMT_EXPR
78 to the EXPR_STMT that is its result. */
81 // -------------------------------------------------------------------------- //
82 // Local Specialization Stack
83 //
84 // Implementation of the RAII helper for creating new local
85 // specializations.
88 {
90 }
93 {
96 }
98 /* True if we've recursed into fn_type_unification too many times. */
102 {
103 tree tmpl;
104 tree args;
105 tree spec;
106 };
109 {
112 };
118 /* Contains canonical template parameter types. The vector is indexed by
119 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
120 TREE_LIST, whose TREE_VALUEs contain the canonical template
121 parameters of various types and levels. */
124 #define UNIFY_ALLOW_NONE 0
125 #define UNIFY_ALLOW_MORE_CV_QUAL 1
126 #define UNIFY_ALLOW_LESS_CV_QUAL 2
127 #define UNIFY_ALLOW_DERIVED 4
128 #define UNIFY_ALLOW_INTEGER 8
129 #define UNIFY_ALLOW_OUTER_LEVEL 16
130 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
131 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
134 tbr_incomplete_type,
135 tbr_ambiguous_baseclass,
136 tbr_success
137 };
160 tree);
218 location_t);
225 /* Make the current scope suitable for access checking when we are
226 processing T. T can be FUNCTION_DECL for instantiated function
227 template, VAR_DECL for static member variable, or TYPE_DECL for
228 alias template (needed by instantiate_decl). */
230 static void
232 {
240 else
244 {
245 saved_access_scope = tree_cons
248 }
249 }
251 /* Restore the scope set up by push_access_scope. T is the node we
252 are processing. */
254 static void
256 {
258 {
261 }
265 else
267 }
269 /* Do any processing required when DECL (a member template
270 declaration) is finished. Returns the TEMPLATE_DECL corresponding
271 to DECL, unless it is a specialization, in which case the DECL
272 itself is returned. */
274 tree
276 {
283 {
284 tree type;
292 {
296 }
298 }
302 {
304 {
307 }
308 else
310 }
311 else
315 }
317 /* Create a template info node. */
319 tree
321 {
326 }
328 /* Return the template info node corresponding to T, whatever T is. */
330 tree
332 {
353 }
355 /* Returns the template nesting level of the indicated class TYPE.
357 For example, in:
358 template <class T>
359 struct A
360 {
361 template <class U>
362 struct B {};
363 };
365 A<T>::B<U> has depth two, while A<T> has depth one.
366 Both A<T>::B<int> and A<int>::B<U> have depth one, if
367 they are instantiations, not specializations.
369 This function is guaranteed to return 0 if passed NULL_TREE so
370 that, for example, `template_class_depth (current_class_type)' is
371 always safe. */
373 int
375 {
382 {
388 }
391 }
393 /* Subroutine of maybe_begin_member_template_processing.
394 Returns true if processing DECL needs us to push template parms. */
396 static bool
398 {
404 }
406 /* Subroutine of maybe_begin_member_template_processing.
407 Push the template parms in PARMS, starting from LEVELS steps into the
408 chain, and ending at the beginning, since template parms are listed
409 innermost first. */
411 static void
413 {
421 current_template_parms
427 NULL);
429 {
438 {
445 {
446 /* Make a CONST_DECL as is done in process_template_parm.
447 It is ugly that we recreate this here; the original
448 version built in process_template_parm is no longer
449 available. */
459 }
464 }
465 }
466 }
468 /* Restore the template parameter context for a member template, a
469 friend template defined in a class definition, or a non-template
470 member of template class. */
472 void
474 {
475 tree parms;
480 {
483 /* Disregard full specializations (c++/60999). */
486 }
489 {
494 {
497 }
500 }
502 /* Remember how many levels of template parameters we pushed so that
503 we can pop them later. */
505 }
507 /* Undo the effects of maybe_begin_member_template_processing. */
509 void
511 {
520 {
524 }
525 }
527 /* Return a new template argument vector which contains all of ARGS,
528 but has as its innermost set of arguments the EXTRA_ARGS. */
530 static tree
532 {
533 tree new_args;
551 }
553 /* Like add_to_template_args, but only the outermost ARGS are added to
554 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
555 (EXTRA_ARGS) levels are added. This function is used to combine
556 the template arguments from a partial instantiation with the
557 template arguments used to attain the full instantiation from the
558 partial instantiation. */
560 static tree
562 {
563 tree new_args;
565 /* If there are more levels of EXTRA_ARGS than there are ARGS,
566 something very fishy is going on. */
569 /* If *all* the new arguments will be the EXTRA_ARGS, just return
570 them. */
574 /* For the moment, we make ARGS look like it contains fewer levels. */
579 /* Now, we restore ARGS to its full dimensions. */
583 }
585 /* Return the N levels of innermost template arguments from the ARGS. */
587 tree
589 {
590 tree new_args;
596 /* If N is 1, just return the innermost set of template arguments. */
600 /* If we're not removing anything, just return the arguments we were
601 given. */
607 /* Make a new set of arguments, not containing the outer arguments. */
614 }
616 /* The inverse of get_innermost_template_args: Return all but the innermost
617 EXTRA_LEVELS levels of template arguments from the ARGS. */
619 static tree
621 {
622 tree new_args;
628 /* If N is 1, just return the outermost set of template arguments. */
632 /* If we're not removing anything, just return the arguments we were
633 given. */
638 /* Make a new set of arguments, not containing the inner arguments. */
645 }
647 /* We've got a template header coming up; push to a new level for storing
648 the parms. */
650 void
652 {
653 /* We use a non-tag-transparent scope here, which causes pushtag to
654 put tags in this scope, rather than in the enclosing class or
655 namespace scope. This is the right thing, since we want
656 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
657 global template class, push_template_decl handles putting the
658 TEMPLATE_DECL into top-level scope. For a nested template class,
659 e.g.:
661 template <class T> struct S1 {
662 template <class T> struct S2 {};
663 };
665 pushtag contains special code to call pushdecl_with_scope on the
666 TEMPLATE_DECL for S2. */
672 /* Add a dummy parameter level while we process the parameter list. */
673 current_template_parms
676 current_template_parms);
677 }
679 /* This routine is called when a specialization is declared. If it is
680 invalid to declare a specialization here, an error is reported and
681 false is returned, otherwise this routine will return true. */
683 static bool
685 {
688 /* [temp.expl.spec]
690 An explicit specialization shall be declared in the namespace of
691 which the template is a member, or, for member templates, in the
692 namespace of which the enclosing class or enclosing class
693 template is a member. An explicit specialization of a member
694 function, member class or static data member of a class template
695 shall be declared in the namespace of which the class template
696 is a member. */
698 {
701 }
703 /* [temp.expl.spec]
705 In an explicit specialization declaration for a member of a class
706 template or a member template that appears in namespace scope,
707 the member template and some of its enclosing class templates may
708 remain unspecialized, except that the declaration shall not
709 explicitly specialize a class member template if its enclosing
710 class templates are not explicitly specialized as well. */
712 {
715 }
718 }
720 /* We've just seen template <>. */
722 bool
724 {
728 }
730 /* Called at then end of processing a declaration preceded by
731 template<>. */
733 void
735 {
738 }
740 /* Any template <>'s that we have seen thus far are not referring to a
741 function specialization. */
743 void
745 {
748 }
750 /* We've just seen a template header. If SPECIALIZATION is nonzero,
751 it was of the form template <>. */
753 static void
755 {
757 template_header_count++;
758 }
760 /* We're beginning an explicit instantiation. */
762 void
764 {
767 }
770 void
772 {
775 }
777 /* An explicit specialization or partial specialization of TMPL is being
778 declared. Check that the namespace in which the specialization is
779 occurring is permissible. Returns false iff it is invalid to
780 specialize TMPL in the current namespace. */
782 static bool
784 {
787 /* [tmpl.expl.spec]
789 An explicit specialization shall be declared in the namespace of
790 which the template is a member, or, for member templates, in the
791 namespace of which the enclosing class or enclosing class
792 template is a member. An explicit specialization of a member
793 function, member class or static data member of a class template
794 shall be declared in the namespace of which the class template is
795 a member. */
798 {
801 }
803 /* Same or super-using namespace. */
805 else
806 {
812 }
813 }
815 /* SPEC is an explicit instantiation. Check that it is valid to
816 perform this explicit instantiation in the current namespace. */
818 static void
820 {
821 tree ns;
823 /* DR 275: An explicit instantiation shall appear in an enclosing
824 namespace of its template. */
830 }
832 // Returns the type of a template specialization only if that
833 // specialization needs to be defined. Otherwise (e.g., if the type has
834 // already been defined), the function returns NULL_TREE.
835 static tree
837 {
838 // An implicit instantiation of an incomplete type implies
839 // the definition of a new class template.
840 //
841 // template<typename T>
842 // struct S;
843 //
844 // template<typename T>
845 // struct S<T*>;
846 //
847 // Here, S<T*> is an implicit instantiation of S whose type
848 // is incomplete.
852 // It can also be the case that TYPE is a completed specialization.
853 // Continuing the previous example, suppose we also declare:
854 //
855 // template<typename T>
856 // requires Integral<T>
857 // struct S<T*>;
858 //
859 // Here, S<T*> refers to the specialization S<T*> defined
860 // above. However, we need to differentiate definitions because
861 // we intend to define a new partial specialization. In this case,
862 // we rely on the fact that the constraints are different for
863 // this declaration than that above.
864 //
865 // Note that we also get here for injected class names and
866 // late-parsed template definitions. We must ensure that we
867 // do not create new type declarations for those cases.
869 {
873 // If there are no template parameters, this cannot be a new
874 // partial template specializtion?
878 // If the constraints are not the same as those of the primary
879 // then, we can probably create a new specialization.
887 // Also, if there's a pre-existing specialization with matching
888 // constraints, then this also isn't new.
891 {
899 }
901 // Create a new type node (and corresponding type decl)
902 // for the newly declared specialization.
908 /* We only need a separate type node for storing the definition of this
909 partial specialization; uses of S<T*> are unconstrained, so all are
910 equivalent. So keep TYPE_CANONICAL the same. */
913 // Build the corresponding type decl.
919 }
922 }
924 /* The TYPE is being declared. If it is a template type, that means it
925 is a partial specialization. Do appropriate error-checking. */
927 tree
929 {
930 tree context;
935 /* A lambda that appears in specialization context is not itself a
936 specialization. */
941 {
945 }
950 {
955 else
958 }
960 {
961 /* This is for ordinary explicit specialization and partial
962 specialization of a template class such as:
964 template <> class C<int>;
966 or:
968 template <class T> class C<T*>;
970 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
973 {
980 {
985 }
986 }
992 /* Trying to define a specialization either without a template<> header
993 or in an inappropriate place. We've already given an error, so just
994 bail now so we don't actually define the specialization. */
996 }
1002 {
1003 /* This is for an explicit specialization of member class
1004 template according to [temp.expl.spec/18]:
1006 template <> template <class U> class C<int>::D;
1008 The context `C<int>' must be an implicit instantiation.
1009 Otherwise this is just a member class template declared
1010 earlier like:
1012 template <> class C<int> { template <class U> class D; };
1013 template <> template <class U> class C<int>::D;
1015 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1016 while in the second case, `C<int>::D' is a primary template
1017 and `C<T>::D' may not exist. */
1021 {
1022 tree t;
1027 {
1032 }
1034 /* Check for invalid specialization after instantiation:
1036 template <> template <> class C<int>::D<int>;
1037 template <> template <class U> class C<int>::D; */
1041 {
1045 {
1046 /* We already have a full specialization of this partial
1047 instantiation, or a full specialization has been
1048 looked up but not instantiated. Reassign it to the
1049 new member specialization template. */
1050 spec_entry elt;
1062 spec_entry **slot
1067 }
1068 else
1069 /* But if we've had an implicit instantiation, that's a
1070 problem ([temp.expl.spec]/6). */
1073 }
1075 /* Mark TYPE as a specialization. And as a result, we only
1076 have one level of template argument for the innermost
1077 class template. */
1082 }
1083 }
1085 {
1086 /* Someday C++0x may allow for enum template specialization. */
1091 else
1092 {
1095 }
1096 }
1099 }
1101 /* Returns nonzero if we can optimize the retrieval of specializations
1102 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1103 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1107 {
1110 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1111 parameter. */
1113 /* The optimized lookup depends on the fact that the
1114 template arguments for the member function template apply
1115 purely to the containing class, which is not true if the
1116 containing class is an explicit or partial
1117 specialization. */
1121 /* It is possible to have a template that is not a member
1122 template and is not a member of a template class:
1124 template <typename T>
1125 struct S { friend A::f(); };
1127 Here, the friend function is a template, but the context does
1128 not have template information. The optimized lookup relies
1129 on having ARGS be the template arguments for both the class
1130 and the function template. */
1132 }
1134 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1135 gone through coerce_template_parms by now. */
1137 static void
1139 {
1140 #ifdef ENABLE_CHECKING
1143 {
1146 {
1153 /* Allow typedefs on the type of a non-type argument, since a
1155 else
1157 }
1158 }
1160 #endif
1161 }
1163 /* Retrieve the specialization (in the sense of [temp.spec] - a
1164 specialization is either an instantiation or an explicit
1165 specialization) of TMPL for the given template ARGS. If there is
1166 no such specialization, return NULL_TREE. The ARGS are a vector of
1167 arguments, or a vector of vectors of arguments, in the case of
1168 templates with more than one level of parameters.
1170 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1171 then we search for a partial specialization matching ARGS. This
1172 parameter is ignored if TMPL is not a class template.
1174 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1175 result is a NONTYPE_ARGUMENT_PACK. */
1177 static tree
1179 {
1189 /* There should be as many levels of arguments as there are
1190 levels of parameters. */
1199 {
1200 tree class_template;
1201 tree class_specialization;
1203 tree fns;
1206 /* The template arguments actually apply to the containing
1207 class. Find the class specialization with those
1208 arguments. */
1210 class_specialization
1214 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1215 for the specialization. */
1219 /* Iterate through the methods with the indicated name, looking
1220 for the one that has an instance of TMPL. */
1223 {
1226 /* using-declarations can add base methods to the method vec,
1227 and we don't want those here. */
1230 }
1232 }
1233 else
1234 {
1236 spec_entry elt;
1245 else
1253 }
1256 }
1258 /* Like retrieve_specialization, but for local declarations. */
1260 tree
1262 {
1268 }
1270 /* Returns nonzero iff DECL is a specialization of TMPL. */
1272 int
1274 {
1275 tree t;
1278 {
1284 }
1285 else
1286 {
1295 }
1298 }
1300 /* Returns nonzero iff DECL is a specialization of friend declaration
1301 FRIEND_DECL according to [temp.friend]. */
1303 bool
1305 {
1312 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1313 of a template class, we want to check if DECL is a specialization
1314 if this. */
1318 {
1319 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1322 }
1327 /* There is nothing to do if this is not a template friend. */
1334 /* [temp.friend/6]
1335 A member of a class template may be declared to be a friend of a
1336 non-template class. In this case, the corresponding member of
1337 every specialization of the class template is a friend of the
1338 class granting friendship.
1340 For example, given a template friend declaration
1342 template <class T> friend void A<T>::f();
1344 the member function below is considered a friend
1346 template <> struct A<int> {
1347 void f();
1348 };
1350 For this type of template friend, TEMPLATE_DEPTH below will be
1351 nonzero. To determine if DECL is a friend of FRIEND, we first
1352 check if the enclosing class is a specialization of another. */
1359 {
1360 /* Next, we check the members themselves. In order to handle
1361 a few tricky cases, such as when FRIEND_DECL's are
1363 template <class T> friend void A<T>::g(T t);
1364 template <class T> template <T t> friend void A<T>::h();
1366 and DECL's are
1368 void A<int>::g(int);
1369 template <int> void A<int>::h();
1371 we need to figure out ARGS, the template arguments from
1372 the context of DECL. This is required for template substitution
1373 of `T' in the function parameter of `g' and template parameter
1374 of `h' in the above examples. Here ARGS corresponds to `int'. */
1381 {
1383 {
1386 else
1388 current_depth++;
1389 }
1391 }
1394 {
1396 tree friend_type;
1397 tree decl_type;
1398 tree friend_args_type;
1399 tree decl_args_type;
1401 /* Make sure that both DECL and FRIEND_DECL are templates or
1402 non-templates. */
1408 {
1409 /* If both are templates, check template parameter list. */
1410 tree friend_parms
1415 friend_parms))
1419 }
1420 else
1428 /* Check if return types match. */
1432 /* Check if function parameter types match, ignoring the
1433 `this' parameter. */
1442 }
1443 else
1444 {
1445 /* DECL is a TYPE_DECL */
1449 /* Make sure that both DECL and FRIEND_DECL are templates or
1450 non-templates. */
1451 is_template
1458 {
1459 tree friend_parms;
1460 /* If both are templates, check the name of the two
1461 TEMPLATE_DECL's first because is_friend didn't. */
1466 /* Now check template parameter list. */
1467 friend_parms
1470 return comp_template_parms
1472 friend_parms);
1473 }
1474 else
1477 }
1478 }
1480 }
1482 /* Register the specialization SPEC as a specialization of TMPL with
1483 the indicated ARGS. IS_FRIEND indicates whether the specialization
1484 is actually just a friend declaration. Returns SPEC, or an
1485 equivalent prior declaration, if available.
1487 We also store instantiations of field packs in the hash table, even
1488 though they are not themselves templates, to make lookup easier. */
1490 static tree
1492 hashval_t hash)
1493 {
1494 tree fn;
1496 spec_entry elt;
1504 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1505 register it; we want the corresponding TEMPLATE_DECL instead.
1506 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1507 the more obvious `uses_template_parms (spec)' to avoid problems
1508 with default function arguments. In particular, given
1509 something like this:
1511 template <class T> void f(T t1, T t = T())
1513 the default argument expression is not substituted for in an
1514 instantiation unless and until it is actually needed. */
1518 /* We don't put these specializations in the hash table, but we might
1519 want to give an error about a mismatch. */
1521 else
1522 {
1530 slot =
1534 else
1536 }
1538 /* We can sometimes try to re-register a specialization that we've
1539 already got. In particular, regenerate_decl_from_template calls
1540 duplicate_decls which will update the specialization list. But,
1541 we'll still get called again here anyhow. It's more convenient
1542 to simply allow this than to try to prevent it. */
1546 {
1548 {
1551 {
1553 fn);
1555 }
1556 else
1557 {
1558 tree clone;
1559 /* This situation should occur only if the first
1560 specialization is an implicit instantiation, the
1561 second is an explicit specialization, and the
1562 implicit instantiation has not yet been used. That
1563 situation can occur if we have implicitly
1564 instantiated a member function and then specialized
1565 it later.
1567 We can also wind up here if a friend declaration that
1568 looked like an instantiation turns out to be a
1569 specialization:
1571 template <class T> void foo(T);
1572 class S { friend void foo<>(int) };
1573 template <> void foo(int);
1575 We transform the existing DECL in place so that any
1576 pointers to it become pointers to the updated
1577 declaration.
1579 If there was a definition for the template, but not
1580 for the specialization, we want this to look as if
1581 there were no definition, and vice versa. */
1584 /* The call to duplicate_decls will have applied
1585 [temp.expl.spec]:
1587 An explicit specialization of a function template
1588 is inline only if it is explicitly declared to be,
1589 and independently of whether its function template
1590 is.
1592 to the primary function; now copy the inline bits to
1593 the various clones. */
1595 {
1602 }
1606 }
1607 }
1609 {
1611 /* Dup decl failed, but this is a new definition. Set the
1612 line number so any errors match this new
1613 definition. */
1617 }
1618 }
1622 /* A specialization must be declared in the same namespace as the
1623 template it is specializing. */
1629 {
1638 /* If TMPL is a forward declaration of a template function, keep a list
1639 of all specializations in case we need to reassign them to a friend
1640 template later in tsubst_friend_function.
1642 Also keep a list of all variable template instantiations so that
1643 process_partial_specialization can check whether a later partial
1644 specialization would have used it. */
1647 }
1650 }
1652 /* Returns true iff two spec_entry nodes are equivalent. */
1656 bool
1658 {
1665 /* tmpl could be a FIELD_DECL for a capture pack. */
1669 {
1670 /* Partial specializations of a variable template can be distinguished by
1671 constraints. */
1675 }
1679 }
1681 /* Returns a hash for a template TMPL and template arguments ARGS. */
1683 static hashval_t
1685 {
1688 }
1690 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1691 ignoring SPEC. */
1693 hashval_t
1695 {
1697 }
1699 /* Recursively calculate a hash value for a template argument ARG, for use
1700 in the hash tables of template specializations. */
1702 hashval_t
1704 {
1716 /* We can get one of these when re-hashing a previous entry in the middle
1717 of substituting into a pack expansion. Just look through it. */
1726 {
1734 {
1739 }
1761 {
1765 {
1768 }
1770 }
1774 {
1777 }
1788 val = iterative_hash_template_arg
1800 val);
1802 val);
1811 /* A lambda can't appear in a template arg, but don't crash on
1812 erroneous input. */
1824 /* Now hash operands as usual. */
1829 }
1832 {
1835 {
1836 // We want an alias specialization that survived strip_typedefs
1837 // to hash differently from its TYPE_CANONICAL, to avoid hash
1838 // collisions that compare as different in template_args_equal.
1839 // These could be dependent specializations that strip_typedefs
1840 // left alone, or untouched specializations because
1841 // coerce_template_parms returns the unconverted template
1842 // arguments if it sees incomplete argument packs.
1845 }
1848 val);
1851 /* Otherwise just compare the types during lookup. */
1860 {
1865 }
1866 }
1869 }
1871 /* Unregister the specialization SPEC as a specialization of TMPL.
1872 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1873 if the SPEC was listed as a specialization of TMPL.
1875 Note that SPEC has been ggc_freed, so we can't look inside it. */
1877 bool
1879 {
1881 spec_entry elt;
1889 {
1894 }
1897 }
1899 /* Like register_specialization, but for local declarations. We are
1900 registering SPEC, an instantiation of TMPL. */
1902 void
1904 {
1906 }
1908 /* TYPE is a class type. Returns true if TYPE is an explicitly
1909 specialized class. */
1911 bool
1913 {
1917 }
1919 /* Print the list of functions at FNS, going through all the overloads
1920 for each element of the list. Alternatively, FNS can not be a
1921 TREE_LIST, in which case it will be printed together with all the
1922 overloads.
1924 MORE and *STR should respectively be FALSE and NULL when the function
1925 is called from the outside. They are used internally on recursive
1926 calls. print_candidates manages the two parameters and leaves NULL
1927 in *STR when it ends. */
1929 static void
1931 {
1937 {
1941 }
1942 else
1943 {
1946 {
1947 /* Pick the prefix string. */
1949 {
1953 }
1957 }
1960 }
1963 {
1966 }
1967 }
1969 /* Print the list of candidate FNS in an error message. FNS can also
1970 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1972 void
1974 {
1978 }
1980 /* Get a (possibly) constrained template declaration for the
1981 purpose of ordering candidates. */
1982 static tree
1984 {
1990 }
1992 /* Among candidates having the same signature, return the
1993 most constrained or NULL_TREE if there is no best candidate.
1994 If the signatures of candidates vary (e.g., template
1995 specialization vs. member function), then there can be no
1996 most constrained.
1998 Note that we don't compare constraints on the functions
1999 themselves, but rather those of their templates. */
2000 static tree
2002 {
2003 // Try to find the best candidate in a first pass.
2006 {
2013 }
2015 // Verify that the champ is better than previous candidates.
2020 }
2023 }
2026 /* Returns the template (one of the functions given by TEMPLATE_ID)
2027 which can be specialized to match the indicated DECL with the
2028 explicit template args given in TEMPLATE_ID. The DECL may be
2029 NULL_TREE if none is available. In that case, the functions in
2030 TEMPLATE_ID are non-members.
2032 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2033 specialization of a member template.
2035 The TEMPLATE_COUNT is the number of references to qualifying
2036 template classes that appeared in the name of the function. See
2037 check_explicit_specialization for a more accurate description.
2039 TSK indicates what kind of template declaration (if any) is being
2040 declared. TSK_TEMPLATE indicates that the declaration given by
2041 DECL, though a FUNCTION_DECL, has template parameters, and is
2042 therefore a template function.
2044 The template args (those explicitly specified and those deduced)
2045 are output in a newly created vector *TARGS_OUT.
2047 If it is impossible to determine the result, an error message is
2048 issued. The error_mark_node is returned to indicate failure. */
2050 static tree
2052 tree decl,
2056 tmpl_spec_kind tsk)
2057 {
2058 tree fns;
2059 tree targs;
2060 tree explicit_targs;
2063 /* A TREE_LIST of templates of which DECL may be a specialization.
2064 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2065 corresponding TREE_PURPOSE is the set of template arguments that,
2066 when used to instantiate the template, would produce a function
2067 with the signature of DECL. */
2077 /* We shouldn't be specializing a member template of an
2078 unspecialized class template; we already gave an error in
2079 check_specialization_scope, now avoid crashing. */
2082 {
2085 }
2093 /* Check for baselinks. */
2098 {
2101 }
2103 {
2106 }
2108 /* Count the number of template headers specified for this
2109 specialization. */
2119 {
2122 tf_warning_or_error,
2126 }
2128 {
2132 {
2133 tree decl_arg_types;
2134 tree fn_arg_types;
2135 tree insttype;
2137 /* In case of explicit specialization, we need to check if
2138 the number of template headers appearing in the specialization
2139 is correct. This is usually done in check_explicit_specialization,
2140 but the check done there cannot be exhaustive when specializing
2141 member functions. Consider the following code:
2143 template <> void A<int>::f(int);
2144 template <> template <> void A<int>::f(int);
2146 Assuming that A<int> is not itself an explicit specialization
2147 already, the first line specializes "f" which is a non-template
2148 member function, whilst the second line specializes "f" which
2149 is a template member function. So both lines are syntactically
2150 correct, and check_explicit_specialization does not reject
2151 them.
2153 Here, we can do better, as we are matching the specialization
2154 against the declarations. We count the number of template
2155 headers, and we check if they match TEMPLATE_COUNT + 1
2156 (TEMPLATE_COUNT is the number of qualifying template classes,
2157 plus there must be another header for the member template
2158 itself).
2160 Notice that if header_count is zero, this is not a
2161 specialization but rather a template instantiation, so there
2162 is no check we can perform here. */
2166 /* Check that the number of template arguments at the
2167 innermost level for DECL is the same as for FN. */
2175 /* DECL might be a specialization of FN. */
2179 /* For a non-static member function, we need to make sure
2180 that the const qualification is the same. Since
2181 get_bindings does not try to merge the "this" parameter,
2182 we must do the comparison explicitly. */
2188 /* Skip the "this" parameter and, for constructors of
2189 classes with virtual bases, the VTT parameter. A
2190 full specialization of a constructor will have a VTT
2191 parameter, but a template never will. */
2192 decl_arg_types
2194 fn_arg_types
2197 /* Function templates cannot be specializations; there are
2198 no partial specializations of functions. Therefore, if
2199 the type of DECL does not match FN, there is no
2200 match.
2202 Note that it should never be the case that we have both
2203 candidates added here, and for regular member functions
2204 below. */
2206 {
2210 }
2212 /* See whether this function might be a specialization of this
2213 template. Suppress access control because we might be trying
2214 to make this specialization a friend, and we have already done
2215 access control for the declaration of the specialization. */
2221 /* We cannot deduce template arguments that when used to
2222 specialize TMPL will produce DECL. */
2225 /* Remove, from the set of candidates, all those functions
2226 whose constraints are not satisfied. */
2230 // Then, try to form the new function type.
2234 fn_arg_types
2239 /* Save this template, and the arguments deduced. */
2241 }
2243 /* FN is an ordinary member function, and we need a
2244 specialization of a member template. */
2245 ;
2247 /* We can get IDENTIFIER_NODEs here in certain erroneous
2248 cases. */
2249 ;
2251 /* This is just an ordinary non-member function. Nothing can
2252 be a specialization of that. */
2253 ;
2255 /* Cannot specialize functions that are created implicitly. */
2256 ;
2257 else
2258 {
2259 tree decl_arg_types;
2261 /* This is an ordinary member function. However, since
2262 we're here, we can assume its enclosing class is a
2263 template class. For example,
2265 template <typename T> struct S { void f(); };
2266 template <> void S<int>::f() {}
2268 Here, S<int>::f is a non-template, but S<int> is a
2269 template class. If FN has the same type as DECL, we
2270 might be in business. */
2273 /* Its enclosing class is an explicit specialization
2274 of a template class. This is not a candidate. */
2279 /* The return types differ. */
2282 /* Adjust the type of DECL in case FN is a static member. */
2289 decl_arg_types))
2292 // If the deduced arguments do not satisfy the constraints,
2293 // this is not a candidate.
2297 // Add the candidate.
2299 }
2300 }
2303 {
2304 /* We have:
2306 [temp.expl.spec]
2308 It is possible for a specialization with a given function
2309 signature to be instantiated from more than one function
2310 template. In such cases, explicit specification of the
2311 template arguments must be used to uniquely identify the
2312 function template specialization being specialized.
2314 Note that here, there's no suggestion that we're supposed to
2315 determine which of the candidate templates is most
2316 specialized. However, we, also have:
2318 [temp.func.order]
2320 Partial ordering of overloaded function template
2321 declarations is used in the following contexts to select
2322 the function template to which a function template
2323 specialization refers:
2325 -- when an explicit specialization refers to a function
2326 template.
2328 So, we do use the partial ordering rules, at least for now.
2329 This extension can only serve to make invalid programs valid,
2330 so it's safe. And, there is strong anecdotal evidence that
2331 the committee intended the partial ordering rules to apply;
2332 the EDG front end has that behavior, and John Spicer claims
2333 that the committee simply forgot to delete the wording in
2334 [temp.expl.spec]. */
2337 {
2340 }
2341 }
2343 // Concepts allows multiple declarations of member functions
2344 // with the same signature. Like above, we need to rely on
2345 // on the partial ordering of those candidates to determine which
2346 // is the best.
2348 {
2350 {
2353 }
2354 }
2357 {
2364 else
2367 }
2371 {
2377 }
2379 /* We have one, and exactly one, match. */
2381 {
2385 // Propagate the candidate's constraints to the declaration.
2388 /* DECL is a re-declaration or partial instantiation of a template
2389 function. */
2392 /* It was a specialization of an ordinary member function in a
2393 template class. */
2395 }
2397 /* It was a specialization of a template. */
2400 {
2405 }
2406 else
2409 }
2411 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2412 but with the default argument values filled in from those in the
2413 TMPL_TYPES. */
2415 static tree
2417 tree tmpl_types)
2418 {
2419 tree new_spec_types;
2427 /* Substitute into the rest of the list. */
2428 new_spec_types =
2432 /* Add the default argument for this parameter. */
2435 new_spec_types);
2436 }
2438 /* DECL is an explicit specialization. Replicate default arguments
2439 from the template it specializes. (That way, code like:
2441 template <class T> void f(T = 3);
2442 template <> void f(double);
2443 void g () { f (); }
2445 works, as required.) An alternative approach would be to look up
2446 the correct default arguments at the call-site, but this approach
2447 is consistent with how implicit instantiations are handled. */
2449 static void
2451 {
2452 tree tmpl;
2453 tree spec_types;
2454 tree tmpl_types;
2455 tree new_spec_types;
2456 tree old_type;
2457 tree new_type;
2458 tree t;
2463 /* See if there's anything we need to do. */
2476 {
2477 /* Remove the this pointer, but remember the object's type for
2478 CV quals. */
2484 {
2485 /* DECL may contain more parameters than TMPL due to the extra
2486 in-charge parameter in constructors and destructors. */
2489 }
2491 {
2494 }
2495 }
2497 /* Compute the merged default arguments. */
2498 new_spec_types =
2501 /* Compute the new FUNCTION_TYPE. */
2503 {
2507 new_spec_types);
2510 /* Put the in-charge parameter back. */
2513 new_spec_types);
2517 new_spec_types);
2518 }
2519 else
2521 new_spec_types);
2531 }
2533 /* Return the number of template headers we expect to see for a definition
2534 or specialization of CTYPE or one of its non-template members. */
2536 int
2538 {
2542 {
2543 /* You're supposed to have one `template <...>' for every
2544 template class, but you don't need one for a full
2545 specialization. For example:
2547 template <class T> struct S{};
2548 template <> struct S<int> { void f(); };
2549 void S<int>::f () {}
2551 is correct; there shouldn't be a `template <>' for the
2552 definition of `S<int>::f'. */
2554 /* If CTYPE does not have template information of any
2555 kind, then it is not a template, nor is it nested
2556 within a template. */
2564 }
2567 }
2569 /* Do a simple sanity check on the template headers that precede the
2570 variable declaration DECL. */
2572 void
2574 {
2579 {
2582 "variable templates only available with "
2585 // Namespace-scope variable templates should have a template header.
2587 }
2589 {
2596 "members of an explicitly specialized class are defined "
2598 }
2599 }
2601 /* Check to see if the function just declared, as indicated in
2602 DECLARATOR, and in DECL, is a specialization of a function
2603 template. We may also discover that the declaration is an explicit
2604 instantiation at this point.
2606 Returns DECL, or an equivalent declaration that should be used
2607 instead if all goes well. Issues an error message if something is
2608 amiss. Returns error_mark_node if the error is not easily
2609 recoverable.
2611 FLAGS is a bitmask consisting of the following flags:
2613 2: The function has a definition.
2614 4: The function is a friend.
2616 The TEMPLATE_COUNT is the number of references to qualifying
2617 template classes that appeared in the name of the function. For
2618 example, in
2620 template <class T> struct S { void f(); };
2621 void S<int>::f();
2623 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2624 classes are not counted in the TEMPLATE_COUNT, so that in
2626 template <class T> struct S {};
2627 template <> struct S<int> { void f(); }
2628 template <> void S<int>::f();
2630 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2631 invalid; there should be no template <>.)
2633 If the function is a specialization, it is marked as such via
2634 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2635 is set up correctly, and it is added to the list of specializations
2636 for that template. */
2638 tree
2640 tree decl,
2643 {
2652 tmpl_spec_kind tsk;
2655 {
2658 else
2660 }
2661 else
2665 {
2668 {
2671 }
2673 {
2675 /* This could be something like:
2677 template <class T> void f(T);
2678 class S { friend void f<>(int); } */
2680 else
2681 {
2682 /* This case handles bogus declarations like template <>
2683 template <class T> void f<int>(); */
2686 declarator);
2688 }
2689 }
2693 /* The error has already been reported in
2694 check_specialization_scope. */
2700 /* Fall through. */
2713 decl);
2716 else
2720 /* Fall through. */
2726 /* In cases like template<> constexpr bool v = true;
2727 We'll give an error in check_template_variable. */
2733 else
2739 {
2740 /* This case handles bogus declarations like template <>
2741 template <class T> void f<int>(); */
2745 declarator);
2747 {
2748 /* Partial specialization of variable template. */
2752 }
2756 else
2760 ok:;
2761 }
2764 /* This is a specialization of a member template, without
2765 specialization the containing class. Something like:
2767 template <class T> struct S {
2768 template <class U> void f (U);
2769 };
2770 template <> template <class U> void S<int>::f(U) {}
2772 That's a specialization -- but of the entire template. */
2778 }
2781 /* This doesn't apply to variable templates. */
2784 {
2788 {
2792 }
2793 }
2796 {
2801 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2803 {
2804 tree fns;
2809 else
2810 {
2811 /* If there is no class context, the explicit instantiation
2812 must be at namespace scope. */
2815 /* Find the namespace binding, using the declaration
2816 context. */
2820 {
2823 }
2824 else
2825 {
2831 }
2832 }
2835 }
2841 {
2843 /* A specialization in class scope. This is invalid,
2844 but the error will already have been flagged by
2845 check_specialization_scope. */
2847 else
2848 {
2849 /* It's not valid to write an explicit instantiation in
2850 class scope, e.g.:
2852 class C { template void f(); }
2854 This case is caught by the parser. However, on
2855 something like:
2857 template class C { void f(); };
2859 (which is invalid) we can get here. The error will be
2860 issued later. */
2861 ;
2862 }
2865 }
2868 {
2869 // We'll match variable templates in start_decl.
2873 /* Find the list of functions in ctype that have the same
2874 name as the declared function. */
2880 {
2885 {
2886 /* From [temp.expl.spec]:
2888 If such an explicit specialization for the member
2889 of a class template names an implicitly-declared
2890 special member function (clause _special_), the
2891 program is ill-formed.
2893 Similar language is found in [temp.explicit]. */
2896 }
2899 }
2902 {
2906 }
2907 else
2908 {
2910 tree ovl;
2912 /* For a type-conversion operator, we cannot do a
2913 name-based lookup. We might be looking for `operator
2914 int' which will be a specialization of `operator T'.
2915 So, we find *all* the conversion operators, and then
2916 select from them. */
2924 {
2926 /* There are no more conversion functions. */
2929 /* Glue all these conversion functions together
2930 with those we already have. */
2933 }
2934 }
2937 {
2940 }
2941 else
2943 }
2945 /* Figure out what exactly is being specialized at this point.
2946 Note that for an explicit instantiation, even one for a
2947 member function, we cannot tell apriori whether the
2948 instantiation is for a member template, or just a member
2949 function of a template class. Even if a member template is
2950 being instantiated, the member template arguments may be
2951 elided if they can be deduced from the rest of the
2952 declaration. */
2955 member_specialization,
2956 template_count,
2957 tsk);
2960 /* We couldn't figure out what this declaration was
2961 specializing. */
2963 else
2964 {
2968 {
2969 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2970 is done by do_decl_instantiation later. */
2976 {
2977 /* If TMPL is not the most general template (for
2978 example, if TMPL is a friend template that is
2979 injected into namespace scope), then there will
2980 be too many levels of TARGS. Remove some of them
2981 here. */
2983 tree new_targs;
2990 }
2993 }
2995 /* If we thought that the DECL was a member function, but it
2996 turns out to be specializing a static member function,
2997 make DECL a static member function as well. */
3003 /* If this is a specialization of a member template of a
3004 template class, we want to return the TEMPLATE_DECL, not
3005 the specialization of it. */
3007 {
3012 {
3013 tree parm;
3017 /* We want to use the argument list specified in the
3018 definition, not in the original declaration. */
3023 }
3026 }
3028 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3034 /* Inherit default function arguments from the template
3035 DECL is specializing. */
3039 /* This specialization has the same protection as the
3040 template it specializes. */
3044 /* 7.1.1-1 [dcl.stc]
3046 A storage-class-specifier shall not be specified in an
3047 explicit specialization...
3049 The parser rejects these, so unless action is taken here,
3050 explicit function specializations will always appear with
3051 global linkage.
3053 The action recommended by the C++ CWG in response to C++
3054 defect report 605 is to make the storage class and linkage
3055 of the explicit specialization match the templated function:
3057 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3058 */
3060 {
3064 /* A concept cannot be specialized. */
3066 {
3068 gen_tmpl);
3070 }
3072 /* This specialization has the same linkage and visibility as
3073 the function template it specializes. */
3076 {
3079 }
3082 {
3085 }
3086 }
3088 /* If DECL is a friend declaration, declared using an
3089 unqualified name, the namespace associated with DECL may
3090 have been set incorrectly. For example, in:
3092 template <typename T> void f(T);
3093 namespace N {
3094 struct S { friend void f<int>(int); }
3095 }
3097 we will have set the DECL_CONTEXT for the friend
3098 declaration to N, rather than to the global namespace. */
3103 /* This is not really a declaration of a specialization.
3104 It's just the name of an instantiation. But, it's not
3105 a request for an instantiation, either. */
3108 /* A specialization is not necessarily COMDAT. */
3114 /* If this is a full specialization, register it so that we can find
3115 it again. Partial specializations will be registered in
3116 process_partial_specialization. */
3121 /* A 'structor should already have clones. */
3127 }
3128 }
3131 }
3133 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3134 parameters. These are represented in the same format used for
3135 DECL_TEMPLATE_PARMS. */
3137 int
3139 {
3140 const_tree p1;
3141 const_tree p2;
3149 {
3161 {
3165 /* If either of the template parameters are invalid, assume
3166 they match for the sake of error recovery. */
3179 }
3180 }
3183 /* One set of parameters has more parameters lists than the
3184 other. */
3188 }
3190 /* Determine whether PARM is a parameter pack. */
3192 bool
3194 {
3195 /* Determine if we have a non-type template parameter pack. */
3202 /* If this is a list of template parameters, we could get a
3203 TYPE_DECL or a TEMPLATE_DECL. */
3207 /* Otherwise it must be a type template parameter. */
3211 }
3213 /* Determine if T is a function parameter pack. */
3215 bool
3217 {
3221 }
3223 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3224 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3226 tree
3228 {
3235 }
3237 /* Return true iff the function parameter PARAM_DECL was expanded
3238 from the function parameter pack PACK. */
3240 bool
3242 {
3247 /* The parameter pack and its pack arguments have the same
3248 DECL_PARM_INDEX. */
3250 }
3252 /* Determine whether ARGS describes a variadic template args list,
3253 i.e., one that is terminated by a template argument pack. */
3255 static bool
3257 {
3259 tree last_parm;
3273 }
3275 /* Generate a new name for the parameter pack name NAME (an
3276 IDENTIFIER_NODE) that incorporates its */
3278 static tree
3280 {
3281 /* Munge the name to include the parameter index. */
3282 #define NUMBUF_LEN 128
3296 }
3298 /* Return true if T is a primary function, class or alias template
3299 instantiation. */
3301 bool
3303 {
3317 }
3319 /* Return true if PARM is a template template parameter. */
3321 bool
3323 {
3325 }
3327 /* Return true iff PARM is a DECL representing a type template
3328 parameter. */
3330 bool
3332 {
3337 }
3339 /* Return the template parameters of T if T is a
3340 primary template instantiation, NULL otherwise. */
3342 tree
3344 {
3349 parms = INNERMOST_TEMPLATE_PARMS
3353 }
3355 /* Return the template parameters of the LEVELth level from the full list
3356 of template parameters PARMS. */
3358 tree
3360 {
3361 tree p;
3372 }
3374 /* Returns the template arguments of T if T is a template instantiation,
3375 NULL otherwise. */
3377 tree
3379 {
3387 }
3389 /* Return the argument pack elements of T if T is a template argument pack,
3390 NULL otherwise. */
3392 tree
3394 {
3400 }
3402 /* Structure used to track the progress of find_parameter_packs_r. */
3403 struct find_parameter_pack_data
3404 {
3405 /* TREE_LIST that will contain all of the parameter packs found by
3406 the traversal. */
3409 /* Set of AST nodes that have been visited by the traversal. */
3411 };
3413 /* Identifies all of the argument packs that occur in a template
3414 argument and appends them to the TREE_LIST inside DATA, which is a
3415 find_parameter_pack_data structure. This is a subroutine of
3416 make_pack_expansion and uses_parameter_packs. */
3417 static tree
3419 {
3425 /* Handle type aliases/typedefs. */
3427 {
3434 }
3436 /* Identify whether this is a parameter pack or not. */
3438 {
3454 {
3455 /* We don't want to walk into the type of a PARM_DECL,
3456 because we don't want to see the type parameter pack. */
3459 }
3462 /* Look through a lambda capture proxy to the field pack. */
3465 {
3471 }
3473 {
3475 find_parameter_packs_r,
3478 }
3485 /* Not a parameter pack. */
3487 }
3490 {
3491 /* Add this parameter pack to the list. */
3493 }
3499 /* This switch statement will return immediately if we don't find a
3500 parameter pack. */
3502 {
3507 /* Check the template itself. */
3510 /* Check the template arguments. */
3526 /* Fall through. */
3568 }
3571 }
3573 /* Determines if the expression or type T uses any parameter packs. */
3574 bool
3576 {
3584 }
3586 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3587 representation a base-class initializer into a parameter pack
3588 expansion. If all goes well, the resulting node will be an
3589 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3590 respectively. */
3591 tree
3593 {
3594 tree result;
3603 {
3604 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3605 class initializer. In this case, the TREE_PURPOSE will be a
3606 _TYPE node (representing the base class expansion we're
3607 initializing) and the TREE_VALUE will be a TREE_LIST
3608 containing the initialization arguments.
3610 The resulting expansion looks somewhat different from most
3611 expansions. Rather than returning just one _EXPANSION, we
3612 return a TREE_LIST whose TREE_PURPOSE is a
3613 TYPE_PACK_EXPANSION containing the bases that will be
3614 initialized. The TREE_VALUE will be identical to the
3615 original TREE_VALUE, which is a list of arguments that will
3616 be passed to each base. We do not introduce any new pack
3617 expansion nodes into the TREE_VALUE (although it is possible
3618 that some already exist), because the TREE_PURPOSE and
3619 TREE_VALUE all need to be expanded together with the same
3620 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3621 resulting TREE_PURPOSE will mention the parameter packs in
3622 both the bases and the arguments to the bases. */
3623 tree purpose;
3624 tree value;
3627 /* Determine which parameter packs will be used by the base
3628 class expansion. */
3635 {
3639 }
3642 {
3643 /* Collect the sets of parameter packs used in each of the
3644 initialization arguments. */
3646 {
3647 /* Determine which parameter packs will be expanded in this
3648 argument. */
3651 }
3652 }
3656 /* Create the pack expansion type for the base type. */
3661 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3662 they will rarely be compared to anything. */
3666 }
3671 /* Build the PACK_EXPANSION_* node. */
3672 result = for_types
3677 {
3678 /* Propagate type and const-expression information. */
3681 }
3682 else
3683 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3684 they will rarely be compared to anything. */
3687 /* Determine which parameter packs will be expanded. */
3693 /* Make sure we found some parameter packs. */
3695 {
3698 else
3701 }
3707 }
3709 /* Checks T for any "bare" parameter packs, which have not yet been
3710 expanded, and issues an error if any are found. This operation can
3711 only be done on full expressions or types (e.g., an expression
3712 statement, "if" condition, etc.), because we could have expressions like:
3714 foo(f(g(h(args)))...)
3716 where "args" is a parameter pack. check_for_bare_parameter_packs
3717 should not be called for the subexpressions args, h(args),
3718 g(h(args)), or f(g(h(args))), because we would produce erroneous
3719 error messages.
3721 Returns TRUE and emits an error if there were bare parameter packs,
3722 returns FALSE otherwise. */
3723 bool
3725 {
3741 {
3744 {
3753 else
3758 else
3762 }
3765 }
3768 }
3770 /* Expand any parameter packs that occur in the template arguments in
3771 ARGS. */
3772 tree
3774 {
3780 /* First, determine if we need to expand anything, and the number of
3781 slots we'll need. */
3783 {
3788 {
3792 else
3794 }
3795 else
3796 {
3798 num_result_args++;
3799 }
3800 }
3802 /* If no expansion is necessary, we're done. */
3806 /* Expand arguments. */
3809 non_default_args_count =
3812 {
3815 {
3822 }
3823 else
3824 {
3827 }
3828 }
3832 }
3834 /* Checks if DECL shadows a template parameter.
3836 [temp.local]: A template-parameter shall not be redeclared within its
3837 scope (including nested scopes).
3839 Emits an error and returns TRUE if the DECL shadows a parameter,
3840 returns FALSE otherwise. */
3842 bool
3844 {
3845 tree olddecl;
3847 /* If we're not in a template, we can't possibly shadow a template
3848 parameter. */
3852 /* Figure out what we're shadowing. */
3857 /* If there's no previous binding for this name, we're not shadowing
3858 anything, let alone a template parameter. */
3862 /* If we're not shadowing a template parameter, we're done. Note
3863 that OLDDECL might be an OVERLOAD (or perhaps even an
3864 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3865 node. */
3869 /* We check for decl != olddecl to avoid bogus errors for using a
3870 name inside a class. We check TPFI to avoid duplicate errors for
3871 inline member templates. */
3877 /* Don't complain about the injected class name, as we've already
3878 complained about the class itself. */
3885 else
3890 }
3892 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3893 ORIG_LEVEL, DECL, and TYPE. */
3895 static tree
3899 tree decl,
3900 tree type)
3901 {
3912 }
3914 /* Find the canonical type parameter for the given template type
3915 parameter. Returns the canonical type parameter, which may be TYPE
3916 if no such parameter existed. */
3918 static tree
3920 {
3921 tree list;
3935 else
3936 {
3941 }
3942 }
3944 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3945 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3946 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3947 new one is created. */
3949 static tree
3951 tsubst_flags_t complain)
3952 {
3957 {
3976 /* Template template parameters need this. */
3978 {
3985 }
3986 }
3989 }
3991 /* Process information from new template parameter PARM and append it
3992 to the LIST being built. This new parameter is a non-type
3993 parameter iff IS_NON_TYPE is true. This new parameter is a
3994 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3995 is in PARM_LOC. */
3997 tree
4000 {
4009 {
4013 {
4017 else
4019 }
4022 }
4025 {
4031 {
4032 /* [temp.param]
4034 The top-level cv-qualifiers on the template-parameter are
4035 ignored when determining its type. */
4040 && !is_parameter_pack
4041 /* If we're in a nested template parameter list, the template
4042 template parameter could be a parameter pack. */
4044 {
4045 /* This template parameter is not a parameter pack, but it
4046 should be. Complain about "bare" parameter packs. */
4049 /* Recover by calling this a parameter pack. */
4051 }
4052 }
4054 /* A template parameter is not modifiable. */
4063 processing_template_decl,
4068 }
4069 else
4070 {
4071 tree t;
4075 {
4077 /* This is for distinguishing between real templates and template
4078 template parameters */
4082 }
4083 else
4084 {
4086 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4089 }
4096 processing_template_decl,
4100 }
4104 /* Build requirements for the type/template parameter.
4105 This must be done after SET_DECL_TEMPLATE_PARM_P or
4106 process_template_parm could fail. */
4111 /* Build the parameter node linking the parameter declaration,
4112 its default argument (if any), and its constraints (if any). */
4117 }
4119 /* The end of a template parameter list has been reached. Process the
4120 tree list into a parameter vector, converting each parameter into a more
4121 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4122 as PARM_DECLs. */
4124 tree
4126 {
4131 /* Pop the dummy parameter level and add the real one. */
4134 current_template_parms
4139 {
4143 }
4148 }
4150 // Explicitly indicate the end of the template parameter list. We assume
4151 // that the current template parameters have been constructed and/or
4152 // managed explicitly, as when creating new template template parameters
4153 // from a shorthand constraint.
4154 void
4156 {
4158 }
4160 /* end_template_decl is called after a template declaration is seen. */
4162 void
4164 {
4170 /* This matches the pushlevel in begin_template_parm_list. */
4175 }
4177 /* Takes a TREE_LIST representing a template parameter and convert it
4178 into an argument suitable to be passed to the type substitution
4179 functions. Note that If the TREE_LIST contains an error_mark
4180 node, the returned argument is error_mark_node. */
4182 tree
4184 {
4197 {
4201 {
4202 /* Turn this argument into a TYPE_ARGUMENT_PACK
4203 with a single element, which expands T. */
4205 #ifdef ENABLE_CHECKING
4206 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
4208 #endif
4213 }
4214 }
4215 else
4216 {
4220 {
4221 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4222 with a single element, which expands T. */
4225 #ifdef ENABLE_CHECKING
4226 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
4228 #endif
4235 }
4236 else
4238 }
4240 }
4242 /* Given a set of template parameters, return them as a set of template
4243 arguments. The template parameters are represented as a TREE_VEC, in
4244 the form documented in cp-tree.h for template arguments. */
4246 static tree
4248 {
4249 tree header;
4254 /* If there is only one level of template parameters, we do not
4255 create a TREE_VEC of TREE_VECs. Instead, we return a single
4256 TREE_VEC containing the arguments. */
4261 {
4269 #ifdef ENABLE_CHECKING
4271 #endif
4275 else
4277 }
4280 }
4282 /* Within the declaration of a template, return the currently active
4283 template parameters as an argument TREE_VEC. */
4285 static tree
4287 {
4289 }
4291 /* Update the declared TYPE by doing any lookups which were thought to be
4292 dependent, but are not now that we know the SCOPE of the declarator. */
4294 tree
4296 {
4307 /* Don't bother building up the args in this case. */
4309 {
4310 /* tsubst in the args corresponding to the template parameters,
4311 including auto if present. Most things will be unchanged, but
4312 make_typename_type and tsubst_qualified_id will resolve
4313 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4316 tree pushed;
4318 {
4322 }
4327 }
4333 {
4336 else
4338 }
4340 }
4342 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4343 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4344 the new template is a member template. */
4346 tree
4348 {
4356 }
4358 struct template_parm_data
4359 {
4360 /* The level of the template parameters we are currently
4361 processing. */
4364 /* The index of the specialization argument we are currently
4365 processing. */
4368 /* An array whose size is the number of template parameters. The
4369 elements are nonzero if the parameter has been used in any one
4370 of the arguments processed so far. */
4373 /* An array whose size is the number of template arguments. The
4374 elements are nonzero if the argument makes use of template
4375 parameters of this level. */
4377 };
4379 /* Subroutine of push_template_decl used to see if each template
4380 parameter in a partial specialization is used in the explicit
4381 argument list. If T is of the LEVEL given in DATA (which is
4382 treated as a template_parm_data*), then DATA->PARMS is marked
4383 appropriately. */
4385 static int
4387 {
4395 {
4398 }
4400 /* Return zero so that for_each_template_parm will continue the
4401 traversal of the tree; we want to mark *every* template parm. */
4403 }
4405 /* Process the partial specialization DECL. */
4407 static tree
4409 {
4416 tree inner_parms;
4417 tree inst;
4427 /* A concept cannot be specialized. */
4429 {
4432 }
4437 /* We check that each of the template parameters given in the
4438 partial specialization is used in the argument list to the
4439 specialization. For example:
4441 template <class T> struct S;
4442 template <class T> struct S<T*>;
4444 The second declaration is OK because `T*' uses the template
4445 parameter T, whereas
4447 template <class T> struct S<int>;
4449 is no good. Even trickier is:
4451 template <class T>
4452 struct S1
4453 {
4454 template <class U>
4455 struct S2;
4456 template <class U>
4457 struct S2<T>;
4458 };
4460 The S2<T> declaration is actually invalid; it is a
4461 full-specialization. Of course,
4463 template <class U>
4464 struct S2<T (*)(U)>;
4466 or some such would have been OK. */
4474 {
4479 NULL,
4481 }
4484 {
4485 /* One of the template parms was not used in a deduced context in the
4486 specialization. */
4488 {
4492 }
4496 }
4501 /* [temp.class.spec]
4503 The argument list of the specialization shall not be identical to
4504 the implicit argument list of the primary template. */
4505 tree main_args
4508 && (!flag_concepts
4511 {
4515 else
4519 }
4521 /* A partial specialization that replaces multiple parameters of the
4522 primary template with a pack expansion is less specialized for those
4523 parameters. */
4525 {
4527 "primary template because it replaces multiple parameters "
4531 }
4533 /* [temp.class.spec]
4535 A partially specialized non-type argument expression shall not
4536 involve template parameters of the partial specialization except
4537 when the argument expression is a simple identifier.
4539 The type of a template parameter corresponding to a specialized
4540 non-type argument shall not be dependent on a parameter of the
4541 specialization.
4543 Also, we verify that pack expansions only occur at the
4544 end of the argument list. */
4548 {
4555 {
4556 /* Extract the arguments from the argument pack. We'll be
4557 iterating over these in the following loop. */
4560 }
4563 {
4565 /* Get the Jth argument in the parameter pack. */
4569 {
4570 /* Pack expansions must come at the end of the
4571 argument list. */
4574 {
4578 else
4581 }
4582 }
4585 /* We only care about the pattern. */
4591 /* This next two lines are the `argument expression is not just a
4592 simple identifier' condition and also the `specialized
4593 non-type argument' bit. */
4597 {
4601 arg);
4602 else
4603 {
4604 /* Look at the corresponding template parameter,
4605 marking which template parameters its type depends
4606 upon. */
4610 {
4611 /* We haven't yet initialized TPD2. Do so now. */
4613 /* The number of parameters here is the number in the
4614 main template, which, as checked in the assertion
4615 above, is NARGS. */
4619 }
4621 /* Mark the template parameters. But this time, we're
4622 looking for the template parameters of the main
4623 template, not in the specialization. */
4630 NULL,
4634 {
4635 /* The type depended on some template parameters.
4636 If they are fully specialized in the
4637 specialization, that's OK. */
4646 "type %qT of template argument %qE depends "
4648 "type %qT of template argument %qE depends "
4650 type,
4651 arg);
4652 }
4653 }
4654 }
4655 }
4656 }
4658 /* We should only get here once. */
4662 // Build the template decl.
4672 /* We didn't register this in check_explicit_specialization so we could
4673 wait until the constraints were set. */
4675 else
4685 {
4691 {
4694 {
4698 "partial specialization of %qD after instantiation "
4700 }
4701 }
4702 }
4705 }
4707 /* PARM is a template parameter of some form; return the corresponding
4708 TEMPLATE_PARM_INDEX. */
4710 static tree
4712 {
4725 }
4727 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4728 parameter packs used by the template parameter PARM. */
4730 static void
4732 {
4733 /* A type parm can't refer to another parm. */
4737 {
4741 }
4748 }
4750 /* PARM is a template parameter pack. Return any parameter packs used in
4751 its type or the type of any of its template parameters. If there are
4752 any such packs, it will be instantiated into a fixed template parameter
4753 list by partial instantiation rather than be fully deduced. */
4755 tree
4757 {
4758 /* This can only be true in a member template. */
4761 /* This can only be true for a parameter pack. */
4764 /* A type parm can't refer to another parm. */
4777 }
4779 /* Check that a template declaration's use of default arguments and
4780 parameter packs is not invalid. Here, PARMS are the template
4781 parameters. IS_PRIMARY is true if DECL is the thing declared by
4782 a primary template. IS_PARTIAL is true if DECL is a partial
4783 specialization.
4785 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4786 declaration (but not a definition); 1 indicates a declaration, 2
4787 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4788 emitted for extraneous default arguments.
4790 Returns TRUE if there were no errors found, FALSE otherwise. */
4792 bool
4795 {
4798 tree parm_level;
4801 /* [temp.param]
4803 A default template-argument shall not be specified in a
4804 function template declaration or a function template definition, nor
4805 in the template-parameter-list of the definition of a member of a
4806 class template. */
4810 /* You can't have a function template declaration in a local
4811 scope, nor you can you define a member of a class template in a
4812 local scope. */
4820 /* A lambda doesn't have an explicit declaration; don't complain
4821 about the parms of the enclosing class. */
4828 /* If this is either a friend defined in the scope of the class
4829 or a member function. */
4835 /* And, if it was a member function, it really was defined in
4836 the scope of the class. */
4839 /* We already checked these parameters when the template was
4840 declared, so there's no need to do it again now. This function
4841 was defined in class scope, but we're processing its body now
4842 that the class is complete. */
4845 /* Core issue 226 (C++0x only): the following only applies to class
4846 templates. */
4849 {
4850 /* [temp.param]
4852 If a template-parameter has a default template-argument, all
4853 subsequent template-parameters shall have a default
4854 template-argument supplied. */
4856 {
4863 {
4873 {
4875 /* For better subsequent error-recovery, we indicate that
4876 there should have been a default argument. */
4879 }
4881 && !is_friend_decl
4882 /* Don't complain about an enclosing partial
4883 specialization. */
4888 /* A fixed parameter pack will be partially
4889 instantiated into a fixed length list. */
4891 {
4892 /* A primary class template can only have one
4893 parameter pack, at the end of the template
4894 parameter list. */
4902 }
4903 }
4904 }
4905 }
4908 || is_partial
4909 || !is_primary
4911 /* For an ordinary class template, default template arguments are
4912 allowed at the innermost level, e.g.:
4913 template <class T = int>
4914 struct S {};
4915 but, in a partial specialization, they're not allowed even
4916 there, as we have in [temp.class.spec]:
4918 The template parameter list of a specialization shall not
4919 contain default template argument values.
4921 So, for a partial specialization, or for a function template
4922 (in C++98/C++03), we look at all of them. */
4923 ;
4924 else
4925 /* But, for a primary class template that is not a partial
4926 specialization we look at all template parameters except the
4927 innermost ones. */
4930 /* Figure out what error message to issue. */
4943 else
4947 /* If we're inside a class definition, there's no need to
4948 examine the parameters to the class itself. On the one
4949 hand, they will be checked when the class is defined, and,
4950 on the other, default arguments are valid in things like:
4951 template <class T = double>
4952 struct S { template <class U> void f(U); };
4953 Here the default argument for `S' has no bearing on the
4954 declaration of `f'. */
4956 else
4957 /* Check everything. */
4963 {
4970 {
4975 {
4977 {
4984 }
4986 /* Clear out the default argument so that we are not
4987 confused later. */
4989 }
4990 }
4992 /* At this point, if we're still interested in issuing messages,
4993 they must apply to classes surrounding the object declared. */
4997 }
5000 }
5002 /* Worker for push_template_decl_real, called via
5003 for_each_template_parm. DATA is really an int, indicating the
5004 level of the parameters we are interested in. If T is a template
5005 parameter of that level, return nonzero. */
5007 static int
5009 {
5015 else
5018 }
5020 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5021 parameters given by current_template_args, or reuses a
5022 previously existing one, if appropriate. Returns the DECL, or an
5023 equivalent one, if it is replaced via a call to duplicate_decls.
5025 If IS_FRIEND is true, DECL is a friend declaration. */
5027 tree
5029 {
5030 tree tmpl;
5031 tree args;
5032 tree info;
5033 tree ctx;
5037 /* True if the template is a member template, in the sense of
5038 [temp.mem]. */
5044 /* See if this is a partial specialization. */
5057 /* For a friend, we want the context of the friend function, not
5058 the type of which it is a friend. */
5062 /* In the case of a virtual function, we want the class in which
5063 it is defined. */
5065 else
5066 /* Otherwise, if we're currently defining some class, the DECL
5067 is assumed to be a member of the class. */
5076 /* See if this is a primary template. */
5079 /* A friend template that specifies a class context, i.e.
5080 template <typename T> friend void A<T>::f();
5081 is not primary. */
5086 else
5090 {
5095 {
5098 }
5100 {
5102 {
5105 }
5107 {
5108 /* [temp.mem]
5110 A destructor shall not be a member template. */
5113 }
5120 {
5121 /* [basic.stc.dynamic.allocation]
5123 An allocation function can be a function
5124 template. ... Template allocation functions shall
5125 have two or more parameters. */
5128 }
5129 }
5135 /* alias-declaration */
5139 else
5140 {
5143 }
5144 }
5146 /* Check to see that the rules regarding the use of default
5147 arguments are not being violated. */
5151 /* Ensure that there are no parameter packs in the type of this
5152 declaration that have not been expanded. */
5154 {
5155 /* Check each of the arguments individually to see if there are
5156 any bare parameter packs. */
5162 {
5165 {
5166 /* This is a PARM_DECL that contains unexpanded parameter
5167 packs. We have already complained about this in the
5168 check_for_bare_parameter_packs call, so just replace
5169 these types with ERROR_MARK_NODE. */
5172 }
5176 }
5178 /* Check for bare parameter packs in the return type and the
5179 exception specifiers. */
5181 /* Errors were already issued, set return type to int
5182 as the frontend doesn't expect error_mark_node as
5183 the return type. */
5187 }
5192 {
5195 }
5208 {
5213 /* If DECL is a TYPE_DECL for a class-template, then there won't
5214 be DECL_LANG_SPECIFIC. The information equivalent to
5215 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5219 {
5220 /* Since a template declaration already existed for this
5221 class-type, we must be redeclaring it here. Make sure
5222 that the redeclaration is valid. */
5224 current_template_parms,
5226 /* We don't need to create a new TEMPLATE_DECL; just use the
5227 one we already had. */
5229 }
5230 else
5231 {
5233 member_template_p);
5238 {
5239 /* A specialization of a member template of a template
5240 class. */
5244 }
5245 }
5246 }
5247 else
5248 {
5254 {
5257 }
5265 {
5266 tree new_tmpl;
5268 /* The declaration is a specialization of a member
5269 template, declared outside the class. Therefore, the
5270 innermost template arguments will be NULL, so we
5271 replace them with the arguments determined by the
5272 earlier call to check_explicit_specialization. */
5275 new_tmpl
5277 member_template_p);
5287 args,
5290 }
5292 /* Make sure the template headers we got make sense. */
5297 {
5302 }
5303 else
5305 {
5310 {
5314 else
5318 /* Avoid crash in import_export_decl. */
5321 }
5326 /* Can happen in erroneous input. */
5328 else
5330 }
5332 /* Check that the parms are used in the appropriate qualifying scopes
5333 in the declarator. */
5337 {
5343 /* Avoid crash in import_export_decl. */
5346 }
5347 }
5352 /* Push template declarations for global functions and types. Note
5353 that we do not try to push a global template friend declared in a
5354 template class; such a thing may well depend on the template
5355 parameters of the class. */
5358 {
5363 /* Hide template friend classes that haven't been declared yet. */
5365 {
5368 }
5369 }
5372 {
5378 {
5381 /* It is a conversion operator. See if the type converted to
5382 depends on innermost template operands. */
5385 depth))
5387 }
5389 /* Give template template parms a DECL_CONTEXT of the template
5390 for which they are a parameter. */
5393 {
5397 }
5403 }
5405 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5406 back to its most general template. If TMPL is a specialization,
5407 ARGS may only have the innermost set of arguments. Add the missing
5408 argument levels if necessary. */
5416 else
5417 {
5422 }
5425 && !is_friend
5428 /* Set DECL_COMDAT on template instantiations; if we force
5429 them to be emitted by explicit instantiation or -frepo,
5430 mark_needed will tell cgraph to do the right thing. */
5434 }
5436 tree
5438 {
5440 }
5442 /* FN is an inheriting constructor that inherits from the constructor
5443 template INHERITED; turn FN into a constructor template with a matching
5444 template header. */
5446 tree
5448 {
5449 tree inner_parms
5452 tree parms
5463 }
5465 /* Called when a class template TYPE is redeclared with the indicated
5466 template PARMS, e.g.:
5468 template <class T> struct S;
5469 template <class T> struct S {}; */
5471 bool
5473 {
5474 tree tmpl;
5475 tree tmpl_parms;
5479 {
5482 }
5486 /* The type is nested in some template class. Nothing to worry
5487 about here; there are no new template parameters for the nested
5488 type. */
5492 {
5494 tmpl);
5496 }
5502 {
5512 }
5515 {
5516 tree tmpl_parm;
5517 tree parm;
5518 tree tmpl_default;
5519 tree parm_default;
5533 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5534 TEMPLATE_DECL. */
5544 {
5548 }
5551 {
5552 /* We have in [temp.param]:
5554 A template-parameter may not be given default arguments
5555 by two different declarations in the same scope. */
5560 }
5563 /* Update the previous template parameters (which are the ones
5564 that will really count) with the new default value. */
5567 /* Update the new parameters, too; they'll be used as the
5568 parameters for any members. */
5571 /* Give each template template parm in this redeclaration a
5572 DECL_CONTEXT of the template for which they are a parameter. */
5574 {
5577 }
5578 }
5580 // Cannot redeclare a class template with a different set of constraints.
5582 {
5587 }
5590 }
5592 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5593 to be used when the caller has already checked
5594 (processing_template_decl
5595 && !instantiation_dependent_expression_p (expr)
5596 && potential_constant_expression (expr))
5597 and cleared processing_template_decl. */
5599 tree
5601 {
5604 complain,
5608 }
5610 /* Simplify EXPR if it is a non-dependent expression. Returns the
5611 (possibly simplified) expression. */
5613 tree
5615 {
5619 /* If we're in a template, but EXPR isn't value dependent, simplify
5620 it. We're supposed to treat:
5622 template <typename T> void f(T[1 + 1]);
5623 template <typename T> void f(T[2]);
5625 as two declarations of the same function, for example. */
5629 {
5630 processing_template_decl_sentinel s;
5632 }
5634 }
5636 tree
5638 {
5640 }
5642 /* True iff T is a specialization of a variable template. */
5644 bool
5646 {
5651 }
5653 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5654 template declaration, or a TYPE_DECL for an alias declaration. */
5656 bool
5658 {
5666 }
5668 /* Return TRUE iff T is a specialization of an alias template. */
5670 bool
5672 {
5673 /* It's an alias template specialization if it's an alias and its
5674 TYPE_NAME is a specialization of a primary template. */
5676 {
5680 {
5683 }
5684 }
5686 }
5688 /* An alias template is complex from a SFINAE perspective if a template-id
5689 using that alias can be ill-formed when the expansion is not, as with
5690 the void_t template. We determine this by checking whether the
5691 expansion for the alias template uses all its template parameters. */
5693 struct uses_all_template_parms_data
5694 {
5697 };
5699 static int
5701 {
5709 }
5711 static bool
5713 {
5728 }
5730 /* Return TRUE iff T is a specialization of a complex alias template with
5731 dependent template-arguments. */
5733 bool
5735 {
5738 && (any_dependent_template_arguments_p
5740 }
5742 /* Return the number of innermost template parameters in TMPL. */
5744 static int
5746 {
5749 }
5751 /* Return either TMPL or another template that it is equivalent to under DR
5752 1286: An alias that just changes the name of a template is equivalent to
5753 the other template. */
5755 static tree
5757 {
5760 {
5763 {
5768 {
5769 tree alias_args = INNERMOST_TEMPLATE_ARGS
5773 /* The alias type is equivalent to the pattern of the
5774 underlying template, so strip the alias. */
5777 }
5778 }
5780 }
5782 }
5784 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5785 must be a function or a pointer-to-function type, as specified
5786 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5787 and check that the resulting function has external linkage. */
5789 static tree
5791 tsubst_flags_t complain)
5792 {
5795 linkage_kind linkage;
5807 /* [temp.arg.nontype]/1
5809 A template-argument for a non-type, non-template template-parameter
5810 shall be one of:
5811 [...]
5812 -- the address of an object or function with external [C++11: or
5813 internal] linkage. */
5816 {
5818 {
5824 else
5827 }
5829 }
5833 {
5835 {
5840 else
5844 }
5846 }
5849 }
5851 /* Subroutine of convert_nontype_argument.
5852 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5853 Emit an error otherwise. */
5855 static bool
5857 tsubst_flags_t complain)
5858 {
5869 {
5873 }
5875 }
5877 /* Returns TRUE iff the address of OP is value-dependent.
5879 14.6.2.4 [temp.dep.temp]:
5880 A non-integral non-type template-argument is dependent if its type is
5881 dependent or it has either of the following forms
5882 qualified-id
5883 & qualified-id
5884 and contains a nested-name-specifier which specifies a class-name that
5885 names a dependent type.
5887 We generalize this to just say that the address of a member of a
5888 dependent class is value-dependent; the above doesn't cover the
5889 address of a static data member named with an unqualified-id. */
5891 static bool
5893 {
5894 /* We could use get_inner_reference here, but there's no need;
5895 this is only relevant for template non-type arguments, which
5896 can only be expressed as &id-expression. */
5898 {
5902 }
5905 }
5907 /* The next set of functions are used for providing helpful explanatory
5908 diagnostics for failed overload resolution. Their messages should be
5909 indented by two spaces for consistency with the messages in
5910 call.c */
5912 static int
5914 {
5916 }
5918 static int
5920 {
5925 }
5927 static int
5929 {
5931 }
5933 static int
5935 {
5941 }
5943 static int
5945 {
5949 }
5951 static int
5953 {
5956 " template parameter %qD is not a parameter pack, but "
5960 }
5962 static int
5964 {
5967 " template argument %qE does not match "
5971 }
5973 static int
5975 {
5979 }
5981 static int
5983 {
5989 }
5991 static int
5993 {
5995 {
6000 else
6002 " deduced conflicting values for non-type parameter "
6004 }
6006 }
6008 static int
6010 {
6013 " variable-sized array type %qT is not "
6015 arg);
6017 }
6019 static int
6021 {
6025 arg);
6027 }
6029 static int
6031 {
6033 {
6039 else
6044 }
6046 }
6048 static int
6050 {
6052 }
6054 static int
6057 {
6059 }
6061 static int
6064 {
6070 }
6072 static int
6075 {
6078 {
6086 }
6088 }
6090 static int
6092 {
6095 " template parameters of a template template argument are "
6098 }
6100 static int
6102 {
6108 }
6110 static int
6112 {
6117 }
6119 static int
6121 {
6125 arg);
6127 }
6129 /* Attempt to convert the non-type template parameter EXPR to the
6130 indicated TYPE. If the conversion is successful, return the
6131 converted value. If the conversion is unsuccessful, return
6132 NULL_TREE if we issued an error message, or error_mark_node if we
6133 did not. We issue error messages for out-and-out bad template
6134 parameters, but not simply because the conversion failed, since we
6135 might be just trying to do argument deduction. Both TYPE and EXPR
6136 must be non-dependent.
6138 The conversion follows the special rules described in
6139 [temp.arg.nontype], and it is much more strict than an implicit
6140 conversion.
6142 This function is called twice for each template argument (see
6143 lookup_template_class for a more accurate description of this
6144 problem). This means that we need to handle expressions which
6145 are not valid in a C++ source, but can be created from the
6146 first call (for instance, casts to perform conversions). These
6147 hacks can go away after we fix the double coercion problem. */
6149 static tree
6151 {
6152 tree expr_type;
6154 /* Detect immediately string literals as invalid non-type argument.
6155 This special-case is not needed for correctness (we would easily
6156 catch this later), but only to provide better diagnostic for this
6157 common user mistake. As suggested by DR 100, we do not mention
6158 linkage issues in the diagnostic as this is not the point. */
6159 /* FIXME we're making this OK. */
6161 {
6167 }
6169 /* Add the ADDR_EXPR now for the benefit of
6170 value_dependent_expression_p. */
6173 {
6177 }
6179 /* If we are in a template, EXPR may be non-dependent, but still
6180 have a syntactic, rather than semantic, form. For example, EXPR
6181 might be a SCOPE_REF, rather than the VAR_DECL to which the
6182 SCOPE_REF refers. Preserving the qualifying scope is necessary
6183 so that access checking can be performed when the template is
6184 instantiated -- but here we need the resolved form so that we can
6185 convert the argument. */
6191 && processing_template_decl
6200 else
6203 /* If the argument is non-dependent, perform any conversions in
6204 non-dependent context as well. */
6209 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6210 to a non-type argument of "nullptr". */
6214 /* In C++11, integral or enumeration non-type template arguments can be
6215 arbitrary constant expressions. Pointer and pointer to
6216 member arguments can be general constant expressions that evaluate
6217 to a null value, but otherwise still need to be of a specific form. */
6219 {
6221 /* A PTRMEM_CST is already constant, and a valid template
6222 argument for a parameter of pointer to member type, we just want
6223 to leave it in that form rather than lower it to a
6228 {
6233 }
6234 }
6236 /* HACK: Due to double coercion, we can get a
6237 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6238 which is the tree that we built on the first call (see
6239 below when coercing to reference to object or to reference to
6240 function). We just strip everything and get to the arg.
6241 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6242 for examples. */
6244 {
6250 {
6251 /* ??? Maybe we could use convert_from_reference here, but we
6252 would need to relax its constraints because the NOP_EXPR
6253 could actually change the type to something more cv-qualified,
6254 and this is not folded by convert_from_reference. */
6259 && (same_type_ignoring_top_level_qualifiers_p
6262 {
6265 }
6266 }
6267 }
6269 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6270 parameter is a pointer to object, through decay and
6271 qualification conversion. Let's strip everything. */
6273 {
6278 {
6279 /* Skip the ADDR_EXPR only if it is part of the decay for
6280 an array. Otherwise, it is part of the original argument
6281 in the source code. */
6286 }
6287 }
6289 /* [temp.arg.nontype]/5, bullet 1
6291 For a non-type template-parameter of integral or enumeration type,
6292 integral promotions (_conv.prom_) and integral conversions
6293 (_conv.integral_) are applied. */
6295 {
6304 /* Notice that there are constant expressions like '4 % 0' which
6305 do not fold into integer constants. */
6307 {
6309 {
6320 /* else cxx_constant_value complained but gave us
6321 a real constant, so go ahead. */
6323 }
6324 else
6326 }
6328 /* Avoid typedef problems. */
6331 }
6332 /* [temp.arg.nontype]/5, bullet 2
6334 For a non-type template-parameter of type pointer to object,
6335 qualification conversions (_conv.qual_) and the array-to-pointer
6336 conversion (_conv.array_) are applied. */
6338 {
6339 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6341 A template-argument for a non-type, non-template template-parameter
6342 shall be one of: [...]
6344 -- the name of a non-type template-parameter;
6345 -- the address of an object or function with external linkage, [...]
6346 expressed as "& id-expression" where the & is optional if the name
6347 refers to a function or array, or if the corresponding
6348 template-parameter is a reference.
6350 Here, we do not care about functions, as they are invalid anyway
6351 for a parameter of type pointer-to-object. */
6354 /* Non-type template parameters are OK. */
6355 ;
6360 {
6362 {
6365 "because %qD is a variable, not the address of "
6368 }
6370 {
6376 }
6377 /* Other values, like integer constants, might be valid
6378 non-type arguments of some other type. */
6380 }
6381 else
6382 {
6383 tree decl;
6388 {
6393 }
6395 {
6401 }
6403 {
6408 }
6409 }
6418 }
6419 /* [temp.arg.nontype]/5, bullet 3
6421 For a non-type template-parameter of type reference to object, no
6422 conversions apply. The type referred to by the reference may be more
6423 cv-qualified than the (otherwise identical) type of the
6424 template-argument. The template-parameter is bound directly to the
6425 template-argument, which must be an lvalue. */
6427 {
6429 expr_type))
6433 {
6438 }
6441 {
6446 }
6448 /* [temp.arg.nontype]/1
6450 A template-argument for a non-type, non-template template-parameter
6451 shall be one of: [...]
6453 -- the address of an object or function with external linkage. */
6456 {
6459 {
6462 "because a reference variable does not have a constant "
6465 }
6466 }
6469 {
6475 }
6477 /* DR 1155 allows internal linkage in C++11 and up. */
6480 {
6486 }
6489 }
6490 /* [temp.arg.nontype]/5, bullet 4
6492 For a non-type template-parameter of type pointer to function, only
6493 the function-to-pointer conversion (_conv.func_) is applied. If the
6494 template-argument represents a set of overloaded functions (or a
6495 pointer to such), the matching function is selected from the set
6496 (_over.over_). */
6498 {
6499 /* If the argument is a template-id, we might not have enough
6500 context information to decay the pointer. */
6502 {
6506 }
6509 /* Null pointer values are OK in C++11. */
6515 }
6516 /* [temp.arg.nontype]/5, bullet 5
6518 For a non-type template-parameter of type reference to function, no
6519 conversions apply. If the template-argument represents a set of
6520 overloaded functions, the matching function is selected from the set
6521 (_over.over_). */
6523 {
6525 {
6527 {
6532 }
6534 }
6541 }
6542 /* [temp.arg.nontype]/5, bullet 6
6544 For a non-type template-parameter of type pointer to member function,
6545 no conversions apply. If the template-argument represents a set of
6546 overloaded member functions, the matching member function is selected
6547 from the set (_over.over_). */
6549 {
6554 /* [temp.arg.nontype] bullet 1 says the pointer to member
6555 expression must be a pointer-to-member constant. */
6559 /* There is no way to disable standard conversions in
6560 resolve_address_of_overloaded_function (called by
6561 instantiate_type). It is possible that the call succeeded by
6562 converting &B::I to &D::I (where B is a base of D), so we need
6563 to reject this conversion here.
6565 Actually, even if there was a way to disable standard conversions,
6566 it would still be better to reject them here so that we can
6567 provide a superior diagnostic. */
6569 {
6571 {
6575 /* If we are just one standard conversion off, explain. */
6579 }
6581 }
6582 }
6583 /* [temp.arg.nontype]/5, bullet 7
6585 For a non-type template-parameter of type pointer to data member,
6586 qualification conversions (_conv.qual_) are applied. */
6588 {
6589 /* [temp.arg.nontype] bullet 1 says the pointer to member
6590 expression must be a pointer-to-member constant. */
6597 }
6599 {
6601 {
6606 }
6608 }
6609 /* A template non-type parameter must be one of the above. */
6610 else
6613 /* Sanity check: did we actually convert the argument to the
6614 right type? */
6618 }
6620 /* Subroutine of coerce_template_template_parms, which returns 1 if
6621 PARM_PARM and ARG_PARM match using the rule for the template
6622 parameters of template template parameters. Both PARM and ARG are
6623 template parameters; the rest of the arguments are the same as for
6624 coerce_template_template_parms.
6625 */
6626 static int
6628 tree arg,
6629 tsubst_flags_t complain,
6630 tree in_decl,
6631 tree outer_args)
6632 {
6641 {
6643 /* We encounter instantiations of templates like
6644 template <template <template <class> class> class TT>
6645 class C; */
6646 {
6653 }
6654 /* Fall through. */
6659 /* Argument is a parameter pack but parameter is not. */
6664 /* The tsubst call is used to handle cases such as
6666 template <int> class C {};
6667 template <class T, template <T> class TT> class D {};
6668 D<int, C> d;
6670 i.e. the parameter list of TT depends on earlier parameters. */
6672 {
6677 }
6681 /* Argument is a parameter pack but parameter is not. */
6688 }
6691 }
6694 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6695 template template parameters. Both PARM_PARMS and ARG_PARMS are
6696 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6697 or PARM_DECL.
6699 Consider the example:
6700 template <class T> class A;
6701 template<template <class U> class TT> class B;
6703 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6704 the parameters to A, and OUTER_ARGS contains A. */
6706 static int
6708 tree arg_parms,
6709 tsubst_flags_t complain,
6710 tree in_decl,
6711 tree outer_args)
6712 {
6723 /* Determine whether we have a parameter pack at the end of the
6724 template template parameter's template parameter list. */
6726 {
6733 {
6747 }
6748 }
6754 /* Check all of the template parameters except the parameter pack at
6755 the end (if any). */
6757 {
6766 outer_args))
6769 }
6772 {
6773 /* Check each of the template parameters in the template
6774 argument against the template parameter pack at the end of
6775 the template template parameter. */
6782 {
6789 outer_args))
6791 }
6792 }
6795 }
6797 /* Verifies that the deduced template arguments (in TARGS) for the
6798 template template parameters (in TPARMS) represent valid bindings,
6799 by comparing the template parameter list of each template argument
6800 to the template parameter list of its corresponding template
6801 template parameter, in accordance with DR150. This
6802 routine can only be called after all template arguments have been
6803 deduced. It will return TRUE if all of the template template
6804 parameter bindings are okay, FALSE otherwise. */
6805 bool
6807 {
6811 /* We're dealing with template parms in this process. */
6817 {
6822 {
6827 {
6828 /* Look inside the argument pack. */
6831 }
6834 {
6838 /* Extract the next argument from the argument
6839 pack. */
6843 /* Look at the pattern of the pack expansion. */
6846 /* Extract the template parameters from the template
6847 argument. */
6853 /* Verify that we can coerce the template template
6854 parameters from the template argument to the template
6855 parameter. This requires an exact match. */
6857 && !coerce_template_template_parms
6859 targ_parms,
6860 tf_none,
6861 tparm,
6862 targs))
6863 {
6866 }
6867 }
6868 }
6869 }
6871 out:
6875 }
6877 /* Since type attributes aren't mangled, we need to strip them from
6878 template type arguments. */
6880 static tree
6882 {
6891 }
6893 // A template declaration can be substituted for a constrained
6894 // template template parameter only when the argument is more
6895 // constrained than the parameter.
6896 static bool
6898 {
6901 /* For now, allow constrained template template arguments
6902 and unconstrained template template parameters. */
6908 // If the template parameter is constrained, we need to rewrite its
6909 // constraints in terms of the ARG's template parameters. This ensures
6910 // that all of the template parameter types will have the same depth.
6911 //
6912 // Note that this is only valid when coerce_template_template_parm is
6913 // true for the innermost template parameters of PARM and ARG. In other
6914 // words, because coercion is successful, this conversion will be valid.
6916 {
6923 }
6926 }
6928 // Convert a placeholder argument into a binding to the original
6929 // parameter. The original parameter is saved as the TREE_TYPE of
6930 // ARG.
6933 {
6936 }
6938 /* Convert the indicated template ARG as necessary to match the
6939 indicated template PARM. Returns the converted ARG, or
6940 error_mark_node if the conversion was unsuccessful. Error and
6941 warning messages are issued under control of COMPLAIN. This
6942 conversion is for the Ith parameter in the parameter list. ARGS is
6943 the full set of template arguments deduced so far. */
6945 static tree
6947 tree arg,
6948 tree args,
6949 tsubst_flags_t complain,
6951 tree in_decl)
6952 {
6953 tree orig_arg;
6954 tree val;
6960 /* Trivially convert placeholders. */
6966 {
6967 /* The template argument was the name of some
6968 member function. That's usually
6969 invalid, but static members are OK. In any
6970 case, grab the underlying fields/functions
6971 and issue an error later if required. */
6974 }
6982 /* When determining whether an argument pack expansion is a template,
6983 look at the pattern. */
6987 /* Deal with an injected-class-name used as a template template arg. */
6989 {
6992 {
7002 }
7003 }
7005 is_tmpl_type =
7021 {
7023 {
7027 }
7030 "to refer to a type member of a template parameter, "
7035 typename_type,
7036 complain);
7039 }
7041 {
7043 {
7045 {
7057 else
7060 }
7061 }
7063 }
7065 {
7067 {
7074 else
7077 }
7079 }
7082 {
7084 {
7088 /* The number of argument required is not known yet.
7089 Just accept it for now. */
7091 else
7092 {
7094 tree argparm;
7096 /* Strip alias templates that are equivalent to another
7097 template. */
7103 args))
7104 {
7107 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7108 TEMPLATE_DECL. */
7110 {
7115 }
7116 }
7117 else
7118 {
7120 {
7127 }
7130 }
7132 // Check that the constraints are compatible before allowing the
7133 // substitution.
7136 {
7138 {
7144 }
7146 }
7147 }
7148 }
7149 else
7151 /* We only form one instance of each template specialization.
7152 Therefore, if we use a non-canonical variant (i.e., a
7153 typedef), any future messages referring to the type will use
7154 the typedef, which is confusing if those future uses do not
7155 themselves also use the typedef. */
7158 }
7159 else
7160 {
7167 {
7170 else
7171 {
7172 /* Not sure if this is reachable, but it doesn't hurt
7173 to be robust. */
7176 }
7177 }
7180 /* We used to call digest_init here. However, digest_init
7181 will report errors, which we don't want when complain
7182 is zero. More importantly, digest_init will try too
7183 hard to convert things: for example, `0' should not be
7184 converted to pointer type at this point according to
7185 the standard. Accepting this is not merely an
7186 extension, since deciding whether or not these
7187 conversions can occur is part of determining which
7188 function template to call, or whether a given explicit
7189 argument specification is valid. */
7191 else
7192 {
7195 }
7203 {
7204 /* Reject template arguments that are references to built-in
7205 functions with no library fallbacks. */
7212 }
7215 {
7216 /* Strip typedefs from the SCOPE_REF. */
7219 complain);
7222 }
7223 }
7226 }
7228 /* Coerces the remaining template arguments in INNER_ARGS (from
7229 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7230 Returns the coerced argument pack. PARM_IDX is the position of this
7231 parameter in the template parameter list. ARGS is the original
7232 template argument list. */
7233 static tree
7236 tree args,
7237 tree inner_args,
7239 tree new_args,
7241 tree in_decl,
7242 tsubst_flags_t complain)
7243 {
7246 tree packed_args;
7247 tree argument_pack;
7254 {
7255 /* When the template parameter is a non-type template parameter pack
7256 or template template parameter pack whose type or template
7257 parameters use parameter packs, we know exactly how many arguments
7258 we are looking for. Build a vector of the instantiated decls for
7259 these template parameters in PACKED_PARMS. */
7260 /* We can't use make_pack_expansion here because it would interpret a
7261 _DECL as a use rather than a declaration. */
7275 /* If we're doing a partial instantiation of a member template,
7276 verify that all of the types used for the non-type
7277 template parameter pack are, in fact, valid for non-type
7278 template parameters. */
7281 {
7284 {
7288 }
7289 /* We don't know how many args we have yet, just
7290 use the unconverted ones for now. */
7292 }
7295 }
7296 /* Check if we have a placeholder pack, which indicates we're
7297 in the context of a introduction list. In that case we want
7298 to match this pack to the single placeholder. */
7302 {
7305 }
7306 else
7309 /* Convert the remaining arguments, which will be a part of the
7310 parameter pack "parm". */
7312 {
7318 {
7319 /* Once we've packed as many args as we have types, stop. */
7323 /* We don't know how many args we have yet, just
7324 use the unconverted ones for now. */
7326 else
7328 }
7331 {
7334 }
7335 else
7338 in_decl);
7342 }
7346 {
7351 }
7356 else
7357 {
7362 }
7365 #ifdef ENABLE_CHECKING
7368 #endif
7370 }
7372 /* Returns the number of pack expansions in the template argument vector
7373 ARGS. */
7375 static int
7377 {
7382 {
7386 }
7388 }
7390 /* Convert all template arguments to their appropriate types, and
7391 return a vector containing the innermost resulting template
7392 arguments. If any error occurs, return error_mark_node. Error and
7393 warning messages are issued under control of COMPLAIN.
7395 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7396 for arguments not specified in ARGS. Otherwise, if
7397 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7398 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7399 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7400 ARGS. */
7402 static tree
7404 tree args,
7405 tree in_decl,
7406 tsubst_flags_t complain,
7409 {
7411 tree orig_inner_args;
7412 tree inner_args;
7413 tree new_args;
7414 tree new_inner_args;
7418 /* When used as a boolean value, indicates whether this is a
7419 variadic template parameter list. Since it's an int, we can also
7420 subtract it from nparms to get the number of non-variadic
7421 parameters. */
7426 /* Likewise for parameters with default arguments. */
7434 /* Determine if there are any parameter packs or default arguments. */
7436 {
7444 }
7447 /* If there are no parameters that follow a parameter pack, we need to
7448 expand any argument packs so that we can deduce a parameter pack from
7449 some non-packed args followed by an argument pack, as in variadic85.C.
7450 If there are such parameters, we need to leave argument packs intact
7451 so the arguments are assigned properly. This can happen when dealing
7452 with a nested class inside a partial specialization of a class
7453 template, as in variadic92.C, or when deducing a template parameter pack
7454 from a sub-declarator, as in variadic114.C. */
7458 /* Count any pack expansion args. */
7464 && require_all_args
7465 && !variadic_args_p
7466 && (!use_default_args
7469 {
7471 {
7473 {
7477 }
7478 else
7485 }
7488 }
7489 /* We can't pass a pack expansion to a non-pack parameter of an alias
7490 template (DR 1430). */
7494 && variadic_args_p
7496 {
7498 {
7500 {
7506 {
7509 "pack expansion argument for non-pack parameter "
7511 else
7513 "pack expansion argument for non-pack parameter "
7517 }
7518 }
7520 found:;
7521 }
7523 }
7525 /* We need to evaluate the template arguments, even though this
7526 template-id may be nested within a "sizeof". */
7535 {
7536 tree arg;
7537 tree parm;
7539 /* Get the Ith template parameter. */
7543 {
7546 }
7548 /* Calculate the next argument. */
7551 else
7556 {
7557 /* Some arguments will be placed in the
7558 template parameter pack PARM. */
7565 {
7566 /* We don't know how many args we have yet, just use the
7567 unconverted (and still packed) ones for now. */
7571 }
7575 /* Store this argument. */
7577 {
7578 lost++;
7579 /* We are done with all of the arguments. */
7581 }
7582 else
7583 {
7586 }
7589 }
7591 {
7593 {
7594 /* "If every valid specialization of a variadic template
7595 requires an empty template parameter pack, the template is
7596 ill-formed, no diagnostic required." So check that the
7597 pattern works with this parameter. */
7602 in_decl);
7604 {
7608 }
7610 /* Recover from missing typename. */
7614 /* We don't know how many args we have yet, just
7615 use the unconverted ones for now. */
7619 }
7620 }
7622 {
7623 /* There must be a default arg in this case. */
7626 /* The position of the first default template argument,
7627 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
7628 Record that. */
7632 }
7633 else
7637 {
7640 }
7642 /* This only occurs if there was an error in the template
7643 parameter list itself (which we would already have
7644 reported) that we are trying to recover from, e.g., a class
7645 template with a parameter list such as
7646 template<typename..., typename>. */
7648 else
7654 lost++;
7656 }
7661 {
7663 {
7668 }
7670 }
7675 #ifdef ENABLE_CHECKING
7679 #endif
7682 }
7684 /* Convert all template arguments to their appropriate types, and
7685 return a vector containing the innermost resulting template
7686 arguments. If any error occurs, return error_mark_node. Error and
7687 warning messages are not issued.
7689 Note that no function argument deduction is performed, and default
7690 arguments are used to fill in unspecified arguments. */
7691 tree
7693 {
7695 }
7697 /* Convert all template arguments to their appropriate type, and
7698 instantiate default arguments as needed. This returns a vector
7699 containing the innermost resulting template arguments, or
7700 error_mark_node if unsuccessful. */
7701 tree
7703 tsubst_flags_t complain)
7704 {
7706 }
7708 /* Like coerce_template_parms. If PARMS represents all template
7709 parameters levels, this function returns a vector of vectors
7710 representing all the resulting argument levels. Note that in this
7711 case, only the innermost arguments are coerced because the
7712 outermost ones are supposed to have been coerced already.
7714 Otherwise, if PARMS represents only (the innermost) vector of
7715 parameters, this function returns a vector containing just the
7716 innermost resulting arguments. */
7718 static tree
7720 tree args,
7721 tree in_decl,
7722 tsubst_flags_t complain,
7725 {
7728 tree coerced_args;
7731 {
7733 tree level;
7739 {
7740 tree l;
7744 require_all_args,
7745 use_default_args);
7746 else
7753 }
7754 }
7755 else
7758 require_all_args,
7759 use_default_args);
7761 }
7763 /* Returns 1 if template args OT and NT are equivalent. */
7765 static int
7767 {
7774 /* For member templates */
7783 {
7800 }
7802 {
7803 /* We get here probably because we are in the middle of substituting
7804 into the pattern of a pack expansion. In that case the
7805 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
7806 interested in. So we want to use the initial pack argument for
7807 the comparison. */
7812 }
7814 {
7817 /* Don't treat an alias template specialization with dependent
7818 arguments as equivalent to its underlying type when used as a
7819 template argument; we need them to be distinct so that we
7820 substitute into the specialization arguments at instantiation
7821 time. And aliases can't be equivalent without being ==, so
7822 we don't need to look any deeper. */
7825 else
7827 }
7830 else
7831 {
7832 /* Try to treat a template non-type argument that has been converted
7833 to the parameter type as equivalent to one that hasn't yet. */
7846 }
7847 }
7849 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
7850 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
7851 NEWARG_PTR with the offending arguments if they are non-NULL. */
7853 static int
7856 {
7869 {
7874 {
7880 }
7881 }
7883 }
7885 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
7886 of template arguments. Returns 0 otherwise. */
7888 int
7890 {
7892 }
7894 static void
7896 {
7906 /* We are called both from instantiate_decl, where we've already had a
7907 tinst_level pushed, and instantiate_template, where we haven't.
7908 Compensate. */
7919 else
7928 }
7931 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
7932 ARGLIST. Valid choices for FNS are given in the cp-tree.def
7933 documentation for TEMPLATE_ID_EXPR. */
7935 tree
7937 {
7938 tree type;
7946 {
7949 }
7952 {
7954 unknown_type_node,
7956 arglist);
7958 }
7965 }
7967 /* Within the scope of a template class S<T>, the name S gets bound
7968 (in build_self_reference) to a TYPE_DECL for the class, not a
7969 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
7970 or one of its enclosing classes, and that type is a template,
7971 return the associated TEMPLATE_DECL. Otherwise, the original
7972 DECL is returned.
7974 Also handle the case when DECL is a TREE_LIST of ambiguous
7975 injected-class-names from different bases. */
7977 tree
7979 {
7983 /* DR 176: A lookup that finds an injected-class-name (10.2
7984 [class.member.lookup]) can result in an ambiguity in certain cases
7985 (for example, if it is found in more than one base class). If all of
7986 the injected-class-names that are found refer to specializations of
7987 the same class template, and if the name is followed by a
7988 template-argument-list, the reference refers to the class template
7989 itself and not a specialization thereof, and is not ambiguous. */
7991 {
7994 {
8000 }
8003 else
8005 }
8011 }
8013 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8014 parameters, find the desired type.
8016 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8018 IN_DECL, if non-NULL, is the template declaration we are trying to
8019 instantiate.
8021 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8022 the class we are looking up.
8024 Issue error and warning messages under control of COMPLAIN.
8026 If the template class is really a local class in a template
8027 function, then the FUNCTION_CONTEXT is the function in which it is
8028 being instantiated.
8030 ??? Note that this function is currently called *twice* for each
8031 template-id: the first time from the parser, while creating the
8032 incomplete type (finish_template_type), and the second type during the
8033 real instantiation (instantiate_template_class). This is surely something
8034 that we want to avoid. It also causes some problems with argument
8035 coercion (see convert_nontype_argument for more information on this). */
8037 static tree
8040 {
8042 tree t;
8045 spec_entry elt;
8046 hashval_t hash;
8049 {
8053 else
8054 {
8061 }
8064 }
8066 {
8069 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8070 an implicit typename for the second A. Deal with it. */
8075 {
8078 }
8079 }
8082 {
8085 }
8087 {
8091 }
8093 {
8096 }
8098 /* Issue an error message if we didn't find a template. */
8100 {
8104 }
8107 /* Make sure it's a user visible template, if it was named by
8108 the user. */
8111 {
8113 {
8117 }
8119 }
8123 /* An alias that just changes the name of a template is equivalent to the
8124 other template, so if any of the arguments are pack expansions, strip
8125 the alias to avoid problems with a pack expansion passed to a non-pack
8126 alias template parameter (DR 1430). */
8131 {
8132 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
8133 template arguments */
8135 tree parm;
8136 tree arglist2;
8137 tree outer;
8141 /* Consider an example where a template template parameter declared as
8143 template <class T, class U = std::allocator<T> > class TT
8145 The template parameter level of T and U are one level larger than
8146 of TT. To proper process the default argument of U, say when an
8147 instantiation `TT<int>' is seen, we need to build the full
8148 arguments containing {int} as the innermost level. Outer levels,
8149 available when not appearing as default template argument, can be
8150 obtained from the arguments of the enclosing template.
8152 Suppose that TT is later substituted with std::vector. The above
8153 instantiation is `TT<int, std::allocator<T> >' with TT at
8154 level 1, and T at level 2, while the template arguments at level 1
8155 becomes {std::vector} and the inner level 2 is {int}. */
8161 {
8162 /* This is an argument of the current template, so we haven't set
8163 DECL_CONTEXT yet. */
8164 tree relevant_template_parms;
8166 /* Parameter levels that are greater than the level of the given
8167 template template parm are irrelevant. */
8174 }
8180 complain,
8190 }
8191 else
8192 {
8194 tree gen_tmpl;
8195 tree type_decl;
8203 /* An error occurred while building the template TEMPL, and a
8204 diagnostic has most certainly been emitted for that
8205 already. Let's propagate that error. */
8214 {
8215 /* We've been given an incomplete set of template arguments.
8216 For example, given:
8218 template <class T> struct S1 {
8219 template <class U> struct S2 {};
8220 template <class U> struct S2<U*> {};
8221 };
8223 we will be called with an ARGLIST of `U*', but the
8224 TEMPLATE will be `template <class T> template
8225 <class U> struct S1<T>::S2'. We must fill in the missing
8226 arguments. */
8227 arglist
8229 arglist);
8231 }
8233 /* Now we should have enough arguments. */
8236 /* From here on, we're only interested in the most general
8237 template. */
8239 /* Calculate the BOUND_ARGS. These will be the args that are
8240 actually tsubst'd into the definition to create the
8241 instantiation. */
8243 complain,
8248 /* We were unable to bind the arguments. */
8251 /* In the scope of a template class, explicit references to the
8252 template class refer to the type of the template, not any
8253 instantiation of it. For example, in:
8255 template <class T> class C { void f(C<T>); }
8257 the `C<T>' is just the same as `C'. Outside of the
8258 class, however, such a reference is an instantiation. */
8262 /* comp_template_args is expensive, check it last. */
8264 arglist))
8267 /* If we already have this specialization, return it. */
8277 /* If the the template's constraints are not satisfied,
8278 then we cannot form a valid type.
8280 Note that the check is deferred until after the hash
8281 lookup. This prevents redundant checks on previously
8282 instantiated specializations. */
8284 {
8286 {
8289 }
8291 }
8295 /* If the deduced arguments are invalid, then the binding
8296 failed. */
8300 complain))
8307 {
8312 }
8322 /* Create the type. */
8324 {
8325 /* The user referred to a specialization of an alias
8326 template represented by GEN_TMPL.
8328 [temp.alias]/2 says:
8330 When a template-id refers to the specialization of an
8331 alias template, it is equivalent to the associated
8332 type obtained by substitution of its
8333 template-arguments for the template-parameters in the
8334 type-id of the alias template. */
8337 /* Note that the call above (by indirectly calling
8338 register_specialization in tsubst_decl) registers the
8339 TYPE_DECL representing the specialization of the alias
8340 template. So next time someone substitutes ARGLIST for
8341 the template parms into the alias template (GEN_TMPL),
8342 she'll get that TYPE_DECL back. */
8346 }
8348 {
8350 {
8359 }
8360 else
8361 {
8362 /* We don't want to call start_enum for this type, since
8363 the values for the enumeration constants may involve
8364 template parameters. And, no one should be interested
8365 in the enumeration constants for such a type. */
8368 }
8372 }
8374 {
8381 /* A local class. Make sure the decl gets registered properly. */
8386 /* This instantiation is another name for the primary
8387 template type. Set the TYPE_CANONICAL field
8388 appropriately. */
8391 /* Some of the template arguments require structural
8392 equality testing, so this template class requires
8393 structural equality testing. */
8395 }
8396 else
8399 /* If we called start_enum or pushtag above, this information
8400 will already be set up. */
8402 {
8409 }
8410 else
8414 {
8420 {
8423 }
8424 }
8428 {
8432 {
8433 tree attributes
8437 ;
8440 else
8445 }
8446 }
8448 /* Let's consider the explicit specialization of a member
8449 of a class template specialization that is implicitly instantiated,
8450 e.g.:
8451 template<class T>
8452 struct S
8453 {
8454 template<class U> struct M {}; //#0
8455 };
8457 template<>
8458 template<>
8459 struct S<int>::M<char> //#1
8460 {
8461 int i;
8462 };
8463 [temp.expl.spec]/4 says this is valid.
8465 In this case, when we write:
8466 S<int>::M<char> m;
8468 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8469 the one of #0.
8471 When we encounter #1, we want to store the partial instantiation
8472 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8474 For all cases other than this "explicit specialization of member of a
8475 class template", we just want to store the most general template into
8476 the CLASSTYPE_TI_TEMPLATE of M.
8478 This case of "explicit specialization of member of a class template"
8479 only happens when:
8480 1/ the enclosing class is an instantiation of, and therefore not
8481 the same as, the context of the most general template, and
8482 2/ we aren't looking at the partial instantiation itself, i.e.
8483 the innermost arguments are not the same as the innermost parms of
8484 the most general template.
8486 So it's only when 1/ and 2/ happens that we want to use the partial
8487 instantiation of the member template in lieu of its most general
8488 template. */
8492 /* the enclosing class must be an instantiation... */
8495 {
8496 tree partial_inst_args;
8499 partial_inst_args =
8505 use_partial_inst_tmpl =
8506 /*...and we must not be looking at the partial instantiation
8507 itself. */
8509 partial_inst_args);
8510 }
8513 /* This case is easy; there are no member templates involved. */
8515 else
8516 {
8517 /* This is a full instantiation of a member template. Find
8518 the partial instantiation of which this is an instance. */
8520 /* Temporarily reduce by one the number of levels in the ARGLIST
8521 so as to avoid comparing the last set of arguments. */
8525 /* FOUND is either a proper class type, or an alias
8526 template specialization. In the later case, it's a
8527 TYPE_DECL, resulting from the substituting of arguments
8528 for parameters in the TYPE_DECL of the alias template
8529 done earlier. So be careful while getting the template
8530 of FOUND. */
8534 }
8536 // Build template info for the new specialization.
8545 /* Note this use of the partial instantiation so we can check it
8546 later in maybe_process_partial_specialization. */
8553 /* Now that the type has been registered on the instantiations
8554 list, we set up the enumerators. Because the enumeration
8555 constants may involve the enumeration type itself, we make
8556 sure to register the type first, and then create the
8557 constants. That way, doing tsubst_expr for the enumeration
8558 constants won't result in recursive calls here; we'll find
8559 the instantiation and exit above. */
8563 /* If the type makes use of template parameters, the
8564 code that generates debugging information will crash. */
8567 /* Possibly limit visibility based on template args. */
8574 }
8575 }
8577 /* Wrapper for lookup_template_class_1. */
8579 tree
8582 {
8583 tree ret;
8589 }
8591 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
8593 tree
8595 {
8596 /* The type of the expression is NULL_TREE since the template-id could refer
8597 to an explicit or partial specialization. */
8600 /* Except that concepts are always bool. */
8603 }
8605 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
8607 tree
8609 {
8613 /* We never want to return a VAR_DECL for a variable concept, since they
8614 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
8628 {
8630 {
8633 }
8635 }
8637 /* If a template-id refers to a specialization of a variable
8638 concept, then the expression is true if and only if the
8639 concept's constraints are satisfied by the given template
8640 arguments.
8642 NOTE: This is an extension of Concepts Lite TS that
8643 allows constraints to be used in expressions. */
8645 {
8648 }
8651 }
8652 \f
8653 struct pair_fn_data
8654 {
8655 tree_fn_t fn;
8657 /* True when we should also visit template parameters that occur in
8658 non-deduced contexts. */
8661 };
8663 /* Called from for_each_template_parm via walk_tree. */
8665 static tree
8667 {
8680 {
8684 /* Fall through. */
8707 /* Since we're not going to walk subtrees, we have to do this
8708 explicitly here. */
8712 /* Fall through. */
8715 /* Check the return type. */
8720 /* Check the parameter types. Since default arguments are not
8721 instantiated until they are needed, the TYPE_ARG_TYPES may
8722 contain expressions that involve template parameters. But,
8723 no-one should be looking at them yet. And, once they're
8724 instantiated, they don't contain template parameters, so
8725 there's no point in looking at them then, either. */
8726 {
8727 tree parm;
8734 /* Since we've already handled the TYPE_ARG_TYPES, we don't
8735 want walk_tree walking into them itself. */
8737 }
8755 /* Fall through. */
8771 /* Record template parameters such as `T' inside `TT<T>'. */
8775 /* Fall through. */
8787 /* A template template parameter is encountered. */
8793 /* Already substituted template template parameter */
8816 /* If there's no type, then this thing must be some expression
8817 involving template parameters. */
8839 }
8841 /* We didn't find any template parameters we liked. */
8843 }
8845 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
8846 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
8847 call FN with the parameter and the DATA.
8848 If FN returns nonzero, the iteration is terminated, and
8849 for_each_template_parm returns 1. Otherwise, the iteration
8850 continues. If FN never returns a nonzero value, the value
8851 returned by for_each_template_parm is 0. If FN is NULL, it is
8852 considered to be the function which always returns 1.
8854 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
8855 parameters that occur in non-deduced contexts. When false, only
8856 visits those template parameters that can be deduced. */
8858 static int
8862 {
8866 /* Set up. */
8871 /* Walk the tree. (Conceptually, we would like to walk without
8872 duplicates, but for_each_template_parm_r recursively calls
8873 for_each_template_parm, so we would need to reorganize a fair
8874 bit to use walk_tree_without_duplicates, so we keep our own
8875 visited list.) */
8878 else
8881 for_each_template_parm_r,
8885 /* Clean up. */
8887 {
8890 }
8893 }
8895 /* Returns true if T depends on any template parameter. */
8897 int
8899 {
8929 else
8930 {
8933 }
8938 }
8940 /* Returns true iff current_function_decl is an incompletely instantiated
8941 template. Useful instead of processing_template_decl because the latter
8942 is set to 0 during instantiate_non_dependent_expr. */
8944 bool
8946 {
8955 }
8957 /* Returns true if T depends on any template parameter with level LEVEL. */
8959 int
8961 {
8964 }
8966 /* Returns TRUE iff INST is an instantiation we don't need to do in an
8967 ill-formed translation unit, i.e. a variable or function that isn't
8968 usable in a constant expression. */
8972 {
8976 }
8978 /* Returns TRUE iff we should refuse to instantiate DECL because it's
8979 neglectable and instantiated from within an erroneous instantiation. */
8981 static bool
8983 {
8994 }
9002 /* We're starting to instantiate D; record the template instantiation context
9003 for diagnostics and to restore it later. */
9005 bool
9007 {
9009 }
9011 /* We're starting to instantiate D; record the template instantiation context
9012 at LOC for diagnostics and to restore it later. */
9014 bool
9016 {
9020 {
9022 "template instantiation depth exceeds maximum of %d"
9024 max_tinst_depth);
9026 }
9028 /* If the current instantiation caused problems, don't let it instantiate
9029 anything else. Do allow deduction substitution and decls usable in
9030 constant expressions. */
9047 }
9049 /* We're done instantiating this template; return to the instantiation
9050 context. */
9052 void
9054 {
9055 /* Restore the filename and line number stashed away when we started
9056 this instantiation. */
9060 }
9062 /* We're instantiating a deferred template; restore the template
9063 instantiation context in which the instantiation was requested, which
9064 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9066 static tree
9068 {
9080 }
9082 /* Returns the TINST_LEVEL which gives the original instantiation
9083 context. */
9087 {
9093 }
9095 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9096 vector of template arguments, as for tsubst.
9098 Returns an appropriate tsubst'd friend declaration. */
9100 static tree
9102 {
9103 tree new_friend;
9108 /* This was a friend declared with an explicit template
9109 argument list, e.g.:
9111 friend void f<>(T);
9113 to indicate that f was a template instantiation, not a new
9114 function declaration. Now, we have to figure out what
9115 instantiation of what template. */
9116 {
9118 tree new_args;
9119 tree tmpl;
9122 /* Friend functions are looked up in the containing namespace scope.
9123 We must enter that scope, to avoid finding member functions of the
9124 current class with same name. */
9139 tsk_none);
9141 }
9145 /* The NEW_FRIEND will look like an instantiation, to the
9146 compiler, but is not an instantiation from the point of view of
9147 the language. For example, we might have had:
9149 template <class T> struct S {
9150 template <class U> friend void f(T, U);
9151 };
9153 Then, in S<int>, template <class U> void f(int, U) is not an
9154 instantiation of anything. */
9160 {
9164 }
9166 /* The mangled name for the NEW_FRIEND is incorrect. The function
9167 is not a template instantiation and should not be mangled like
9168 one. Therefore, we forget the mangling here; we'll recompute it
9169 later if we need it. */
9171 {
9174 }
9177 {
9178 tree old_decl;
9179 tree new_friend_template_info;
9180 tree new_friend_result_template_info;
9181 tree ns;
9184 /* We must save some information from NEW_FRIEND before calling
9185 duplicate decls since that function will free NEW_FRIEND if
9186 possible. */
9188 new_friend_is_defn =
9193 {
9194 /* This declaration is a `primary' template. */
9197 new_friend_result_template_info
9199 }
9200 else
9203 /* Make the init_value nonzero so pushdecl knows this is a defn. */
9207 /* Inside pushdecl_namespace_level, we will push into the
9208 current namespace. However, the friend function should go
9209 into the namespace of the template. */
9219 {
9220 /* This new friend declaration matched an existing
9221 declaration. For example, given:
9223 template <class T> void f(T);
9224 template <class U> class C {
9225 template <class T> friend void f(T) {}
9226 };
9228 the friend declaration actually provides the definition
9229 of `f', once C has been instantiated for some type. So,
9230 old_decl will be the out-of-class template declaration,
9231 while new_friend is the in-class definition.
9233 But, if `f' was called before this point, the
9234 instantiation of `f' will have DECL_TI_ARGS corresponding
9235 to `T' but not to `U', references to which might appear
9236 in the definition of `f'. Previously, the most general
9237 template for an instantiation of `f' was the out-of-class
9238 version; now it is the in-class version. Therefore, we
9239 run through all specialization of `f', adding to their
9240 DECL_TI_ARGS appropriately. In particular, they need a
9241 new set of outer arguments, corresponding to the
9242 arguments for this class instantiation.
9244 The same situation can arise with something like this:
9246 friend void f(int);
9247 template <class T> class C {
9248 friend void f(T) {}
9249 };
9251 when `C<int>' is instantiated. Now, `f(int)' is defined
9252 in the class. */
9255 /* On the other hand, if the in-class declaration does
9256 *not* provide a definition, then we don't want to alter
9257 existing definitions. We can just leave everything
9258 alone. */
9259 ;
9260 else
9261 {
9265 /* Overwrite whatever template info was there before, if
9266 any, with the new template information pertaining to
9267 the declaration. */
9271 {
9272 /* We should have called reregister_specialization in
9273 duplicate_decls. */
9278 /* Instantiate it if the global has already been used. */
9282 }
9283 else
9284 {
9285 tree t;
9287 /* Indicate that the old function template is a partial
9288 instantiation. */
9296 /* Reassign any specializations already in the hash table
9297 to the new more general template, and add the
9298 additional template args. */
9302 {
9304 spec_entry elt;
9316 register_specialization
9319 }
9321 }
9322 }
9324 /* The information from NEW_FRIEND has been merged into OLD_DECL
9325 by duplicate_decls. */
9327 }
9328 }
9329 else
9330 {
9334 /* In the code
9335 template <class T> class C {
9336 template <class U> friend void C1<U>::f (); // case 1
9337 friend void C2<T>::f (); // case 2
9338 };
9339 we only need to make sure CONTEXT is a complete type for
9340 case 2. To distinguish between the two cases, we note that
9341 CONTEXT of case 1 remains dependent type after tsubst while
9342 this isn't true for case 2. */
9352 {
9354 /* do_friend adds the TEMPLATE_DECL for any member friend
9355 template even if it isn't a member template, i.e.
9356 template <class T> friend A<T>::f();
9357 Look through it in that case. */
9361 /* Check to see that the declaration is really present, and,
9362 possibly obtain an improved declaration. */
9367 }
9368 }
9371 }
9373 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9374 template arguments, as for tsubst.
9376 Returns an appropriate tsubst'd friend type or error_mark_node on
9377 failure. */
9379 static tree
9381 {
9382 tree friend_type;
9383 tree tmpl;
9384 tree context;
9387 {
9390 }
9395 {
9398 else
9400 }
9402 /* Look for a class template declaration. We look for hidden names
9403 because two friend declarations of the same template are the
9404 same. For example, in:
9406 struct A {
9407 template <typename> friend class F;
9408 };
9409 template <typename> struct B {
9410 template <typename> friend class F;
9411 };
9413 both F templates are the same. */
9417 /* But, if we don't find one, it might be because we're in a
9418 situation like this:
9420 template <class T>
9421 struct S {
9422 template <class U>
9423 friend struct S;
9424 };
9426 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9427 for `S<int>', not the TEMPLATE_DECL. */
9429 {
9432 }
9435 {
9436 /* The friend template has already been declared. Just
9437 check to see that the declarations match, and install any new
9438 default parameters. We must tsubst the default parameters,
9439 of course. We only need the innermost template parameters
9440 because that is all that redeclare_class_template will look
9441 at. */
9444 {
9445 tree parms;
9446 location_t saved_input_location;
9456 }
9459 }
9460 else
9461 {
9462 /* The friend template has not already been declared. In this
9463 case, the instantiation of the template class will cause the
9464 injection of this template into the global scope. */
9469 /* The new TMPL is not an instantiation of anything, so we
9470 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9471 the new type because that is supposed to be the corresponding
9472 template decl, i.e., TMPL. */
9479 /* Inject this template into the global scope. */
9481 }
9484 {
9487 else
9489 }
9492 }
9494 /* Returns zero if TYPE cannot be completed later due to circularity.
9495 Otherwise returns one. */
9497 static int
9499 {
9509 else
9511 }
9515 /* Apply any attributes which had to be deferred until instantiation
9516 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
9517 ARGS, COMPLAIN, IN_DECL are as tsubst. */
9519 static void
9522 {
9524 tree t;
9529 {
9533 }
9536 {
9540 }
9541 else
9545 {
9550 {
9553 {
9560 {
9567 clauses
9571 else
9573 }
9574 /* If the first attribute argument is an identifier, don't
9575 pass it through tsubst. Attributes like mode, format,
9576 cleanup and several target specific attributes expect it
9577 unmodified. */
9580 {
9581 tree chain
9583 in_decl,
9588 chain);
9589 }
9591 {
9592 /* An attribute pack expansion. */
9594 tree pack = (tsubst_pack_expansion
9598 {
9602 }
9604 }
9605 else
9611 }
9612 else
9614 }
9617 }
9618 }
9620 /* Perform (or defer) access check for typedefs that were referenced
9621 from within the template TMPL code.
9622 This is a subroutine of instantiate_decl and instantiate_class_template.
9623 TMPL is the template to consider and TARGS is the list of arguments of
9624 that template. */
9626 static void
9628 {
9629 location_t saved_location;
9640 {
9652 /* Make access check error messages point to the location
9653 of the use of the typedef. */
9657 tf_warning_or_error);
9658 }
9660 }
9662 static tree
9664 {
9666 tree typedecl;
9667 tree pbinfo;
9668 tree base_list;
9670 tree fn_context;
9679 /* Figure out which template is being instantiated. */
9683 /* Determine what specialization of the original template to
9684 instantiate. */
9687 {
9690 }
9692 {
9693 /* This TYPE is actually an instantiation of a partial
9694 specialization. We replace the innermost set of ARGS with
9695 the arguments appropriate for substitution. For example,
9696 given:
9698 template <class T> struct S {};
9699 template <class T> struct S<T*> {};
9701 and supposing that we are instantiating S<int*>, ARGS will
9702 presently be {int*} -- but we need {int}. */
9705 }
9706 else
9707 {
9710 }
9712 /* If the template we're instantiating is incomplete, then clearly
9713 there's nothing we can do. */
9717 /* If we've recursively instantiated too many templates, stop. */
9721 /* Now we're really doing the instantiation. Mark the type as in
9722 the process of being defined. */
9725 /* We may be in the middle of deferred access check. Disable
9726 it now. */
9733 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
9738 else
9739 {
9742 }
9743 /* Use #pragma pack from the template context. */
9749 /* Set the input location to the most specialized template definition.
9750 This is needed if tsubsting causes an error. */
9762 {
9765 /* Adjust visibility for template arguments. */
9767 }
9773 /* We should never instantiate a nested class before its enclosing
9774 class; we need to look up the nested class by name before we can
9775 instantiate it, and that lookup should instantiate the enclosing
9776 class. */
9782 {
9783 tree pbase_binfo;
9784 tree pushed_scope;
9787 /* We must enter the scope containing the type, as that is where
9788 the accessibility of types named in dependent bases are
9789 looked up from. */
9792 /* Substitute into each of the bases to determine the actual
9793 basetypes. */
9795 {
9796 tree base;
9802 {
9803 expanded_bases =
9810 }
9813 {
9815 /* Extract the already-expanded base class. */
9817 else
9818 /* Substitute to figure out the base class. */
9820 NULL_TREE);
9828 }
9829 }
9831 /* The list is now in reverse order; correct that. */
9836 }
9837 /* Now call xref_basetypes to set up all the base-class
9838 information. */
9846 /* Now that our base classes are set up, enter the scope of the
9847 class, so that name lookups into base classes, etc. will work
9848 correctly. This is precisely analogous to what we do in
9849 begin_class_definition when defining an ordinary non-template
9850 class, except we also need to push the enclosing classes. */
9853 /* Now members are processed in the order of declaration. */
9856 {
9860 {
9862 {
9863 /* Build new CLASSTYPE_NESTED_UTDS. */
9865 tree newtag;
9871 /* If the member is a class template, then -- even after
9872 substitution -- there may be dependent types in the
9873 template argument list for the class. We increment
9874 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
9875 that function will assume that no types are dependent
9876 when outside of a template. */
9886 {
9890 /* Unfortunately, lookup_template_class sets
9891 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
9892 instantiation (i.e., for the type of a member
9893 template class nested within a template class.)
9894 This behavior is required for
9895 maybe_process_partial_specialization to work
9896 correctly, but is not accurate in this case;
9897 the TAG is not an instantiation of anything.
9898 (The corresponding TEMPLATE_DECL is an
9899 instantiation, but the TYPE is not.) */
9902 /* Now, we call pushtag to put this NEWTAG into the scope of
9903 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
9904 pushtag calling push_template_decl. We don't have to do
9905 this for enums because it will already have been done in
9906 tsubst_enum. */
9910 }
9911 }
9913 {
9914 /* Build new TYPE_METHODS. */
9915 tree r;
9924 /* Instantiate members marked with attribute used. */
9930 }
9933 /* A closure type for a lambda in a default argument for a
9934 member template. Ignore it; it will be instantiated with
9936 else
9937 {
9938 /* Build new TYPE_FIELDS. */
9940 {
9941 tree condition;
9944 condition =
9954 }
9956 {
9957 tree r;
9961 /* The file and line for this declaration, to
9962 assist in error message reporting. Since we
9963 called push_tinst_level above, we don't need to
9964 restore these. */
9974 {
9975 /* A capture pack became multiple fields. */
9978 }
9981 {
9985 {
9986 /* In [temp.inst]:
9988 [t]he initialization (and any associated
9989 side-effects) of a static data member does
9990 not occur unless the static data member is
9991 itself used in a way that requires the
9992 definition of the static data member to
9993 exist.
9995 Therefore, we do not substitute into the
9996 initialized for the static data member here. */
9997 finish_static_data_member_decl
10003 /* Instantiate members marked with attribute used. */
10006 }
10008 {
10009 /* Determine whether R has a valid type and can be
10010 completed later. If R is invalid, then its type
10011 is replaced by error_mark_node. */
10017 {
10020 }
10021 }
10023 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10024 such a thing will already have been added to the field
10025 list by tsubst_enum in finish_member_declaration in the
10026 CLASSTYPE_NESTED_UTDS case above. */
10030 {
10033 }
10034 }
10035 }
10036 }
10037 }
10038 else
10039 {
10042 {
10043 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10049 {
10050 /* template <class T> friend class C; */
10053 }
10055 {
10056 /* template <class T> friend class C::D; */
10062 }
10065 {
10066 /* This could be either
10068 friend class T::C;
10070 when dependent_type_p is false or
10072 template <class U> friend class T::C;
10074 otherwise. */
10077 /* Bump processing_template_decl for correct
10078 dependent_type_p calculation. */
10083 }
10086 {
10087 /* friend class C;
10089 where C hasn't been declared yet. Let's lookup name
10090 from namespace scope directly, bypassing any name that
10091 come from dependent base class. */
10094 /* The call to xref_tag_from_type does injection for friend
10095 classes. */
10097 friend_type =
10101 }
10103 /* friend class C<T>; */
10106 /* Otherwise it's
10108 friend class C;
10110 where C is already declared or
10112 friend class C<int>;
10114 We don't have to do anything in these cases. */
10117 /* Trick make_friend_class into realizing that the friend
10118 we're adding is a template, not an ordinary class. It's
10119 important that we use make_friend_class since it will
10120 perform some error-checking and output cross-reference
10121 information. */
10129 }
10130 else
10131 {
10132 /* Build new DECL_FRIENDLIST. */
10133 tree r;
10135 /* The file and line for this declaration, to
10136 assist in error message reporting. Since we
10137 called push_tinst_level above, we don't need to
10138 restore these. */
10142 {
10145 }
10150 {
10153 }
10154 }
10155 }
10156 }
10159 {
10160 /* Restore these before substituting into the lambda capture
10161 initializers. */
10164 }
10167 {
10170 {
10175 /* We need to instantiate the capture list from the template
10176 after we've instantiated the closure members, but before we
10177 consider adding the conversion op. Also keep any captures
10178 that may have been added during instantiation of the op(). */
10180 tree tmpl_cap
10189 }
10190 else
10192 }
10194 /* Set the file and line number information to whatever is given for
10195 the class itself. This puts error messages involving generated
10196 implicit functions at a predictable point, and the same point
10197 that would be used for non-template classes. */
10204 /* We don't instantiate default arguments for member functions. 14.7.1:
10206 The implicit instantiation of a class template specialization causes
10207 the implicit instantiation of the declarations, but not of the
10208 definitions or default arguments, of the class member functions,
10209 member classes, static data members and member templates.... */
10211 /* Some typedefs referenced from within the template code need to be access
10212 checked at template instantiation time, i.e now. These types were
10213 added to the template at parsing time. Let's get those and perform
10214 the access checks then. */
10224 /* The vtable for a template class can be emitted in any translation
10225 unit in which the class is instantiated. When there is no key
10226 method, however, finish_struct_1 will already have added TYPE to
10227 the keyed_classes list. */
10232 }
10234 /* Wrapper for instantiate_class_template_1. */
10236 tree
10238 {
10239 tree ret;
10244 }
10246 static tree
10248 {
10249 tree r;
10255 else
10256 {
10263 }
10265 }
10267 /* Given a function parameter pack TMPL_PARM and some function parameters
10268 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10269 and set *SPEC_P to point at the next point in the list. */
10271 tree
10273 {
10274 /* Collect all of the extra "packed" parameters into an
10275 argument pack. */
10276 tree parmvec;
10277 tree parmtypevec;
10288 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10293 {
10296 }
10298 /* Build the argument packs. */
10305 }
10307 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10308 NONTYPE_ARGUMENT_PACK. */
10310 static tree
10312 {
10314 }
10316 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10317 pack expansion with no extra args, 2 if it has extra args, or 0
10318 if it is not a pack expansion. */
10320 static int
10322 {
10328 /* A decl pack is itself an expansion. */
10335 }
10338 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10340 static tree
10342 {
10349 }
10351 /* This is a subroutine of tsubst_pack_expansion.
10353 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10354 mechanism to store the (non complete list of) arguments of the
10355 substitution and return a non substituted pack expansion, in order
10356 to wait for when we have enough arguments to really perform the
10357 substitution. */
10359 static bool
10363 {
10364 /* If one pack has an expansion and another pack has a normal
10365 argument or if one pack has an empty argument and an another
10366 one hasn't then tsubst_pack_expansion cannot perform the
10367 substitution and need to fall back on the
10368 PACK_EXPANSION_EXTRA mechanism. */
10376 {
10379 parm_pack;
10381 {
10386 /* We can't substitute a pack expansion with extra args into
10387 our pattern. */
10391 else
10393 }
10397 }
10399 }
10401 /* [temp.variadic]/6 says that:
10403 The instantiation of a pack expansion [...]
10404 produces a list E1,E2, ..., En, where N is the number of elements
10405 in the pack expansion parameters.
10407 This subroutine of tsubst_pack_expansion produces one of these Ei.
10409 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10410 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10411 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10412 INDEX is the index 'i' of the element Ei to produce. ARGS,
10413 COMPLAIN, and IN_DECL are the same parameters as for the
10414 tsubst_pack_expansion function.
10416 The function returns the resulting Ei upon successful completion,
10417 or error_mark_node.
10419 Note that this function possibly modifies the ARGS parameter, so
10420 it's the responsibility of the caller to restore it. */
10422 static tree
10424 tree parm_packs,
10426 tree args /* This parm gets
10428 tsubst_flags_t complain,
10429 tree in_decl)
10430 {
10431 tree t;
10434 /* For each parameter pack, change the substitution of the parameter
10435 pack to the ith argument in its argument pack, then expand the
10436 pattern. */
10438 {
10443 ith_elem_is_expansion |=
10446 /* Select the Ith argument from the pack. */
10449 {
10451 {
10456 }
10457 else
10459 }
10460 else
10461 {
10466 {
10468 /* Update the corresponding argument. */
10470 }
10471 else
10472 /* Re-use the ARGUMENT_PACK_SELECT. */
10474 }
10476 }
10478 /* Substitute into the PATTERN with the (possibly altered)
10479 arguments. */
10481 /* Expanding a fixed parameter pack from
10482 coerce_template_parameter_pack. */
10487 {
10490 else
10493 }
10497 else
10500 /* If the Ith argument pack element is a pack expansion, then
10501 the Ith element resulting from the substituting is going to
10502 be a pack expansion as well. */
10507 }
10509 /* Substitute ARGS into T, which is an pack expansion
10510 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
10511 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
10512 (if only a partial substitution could be performed) or
10513 ERROR_MARK_NODE if there was an error. */
10514 tree
10516 tree in_decl)
10517 {
10518 tree pattern;
10522 tree result;
10530 /* Add in any args remembered from an earlier partial instantiation. */
10535 /* Determine the argument packs that will instantiate the parameter
10536 packs used in the expansion expression. While we're at it,
10537 compute the number of arguments to be expanded and make sure it
10538 is consistent. */
10541 {
10548 {
10552 else
10555 }
10557 {
10558 /* We know we have correct local_specializations if this
10559 expansion is at function scope, or if we're dealing with a
10560 local parameter in a requires expression; for the latter,
10561 tsubst_requires_expr set it up appropriately. */
10564 else
10565 {
10566 /* We can't rely on local_specializations for a parameter
10567 name used later in a function declaration (such as in a
10568 late-specified return type). Even if it exists, it might
10569 have the wrong value for a recursive call. Just make a
10570 dummy decl, since it's only used for its type. */
10573 /* Partial instantiation of the parm_pack, we can't build
10574 up an argument pack yet. */
10576 else
10579 }
10580 }
10583 else
10584 {
10590 }
10597 /* This can only happen if we forget to expand an argument
10598 pack somewhere else. Just return an error, silently. */
10599 {
10603 }
10606 {
10610 /* Don't bother trying to do a partial substitution with
10611 incomplete packs; we'll try again after deduction. */
10618 {
10624 pattern);
10625 else
10628 pattern);
10630 }
10632 /* Keep track of the parameter packs and their corresponding
10633 argument packs. */
10636 }
10637 else
10638 {
10639 /* We can't substitute for this parameter pack. We use a flag as
10640 well as the missing_level counter because function parameter
10641 packs don't have a level. */
10643 }
10644 }
10646 /* If the expansion is just T..., return the matching argument pack. */
10649 {
10654 /* Otherwise use the normal path so we get convert_from_reference. */
10655 }
10657 /* We cannot expand this expansion expression, because we don't have
10658 all of the argument packs we need. */
10660 {
10661 /* We got some full packs, but we can't substitute them in until we
10662 have values for all the packs. So remember these until then. */
10667 }
10669 {
10670 /* There were no real arguments, we're just replacing a parameter
10671 pack with another version of itself. Substitute into the
10672 pattern and return a PACK_EXPANSION_*. The caller will need to
10673 deal with that. */
10677 else
10681 }
10686 {
10687 /* We're in a late-specified return type, so create our own local
10688 specializations map; the current map is either NULL or (in the
10689 case of recursive unification) might have bindings that we don't
10690 want to use or alter. */
10693 }
10695 /* For each argument in each argument pack, substitute into the
10696 pattern. */
10699 {
10701 i,
10703 in_decl);
10706 {
10709 }
10710 }
10712 /* Update ARGS to restore the substitution from parameter packs to
10713 their argument packs. */
10715 {
10721 else
10722 {
10730 /* Update the corresponding argument. */
10734 else
10736 }
10737 }
10740 {
10743 }
10746 }
10748 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
10749 TMPL. We do this using DECL_PARM_INDEX, which should work even with
10750 parameter packs; all parms generated from a function parameter pack will
10751 have the same DECL_PARM_INDEX. */
10753 tree
10755 {
10757 tree patparm;
10760 {
10766 }
10767 else
10768 {
10773 }
10776 }
10778 /* Substitute ARGS into the vector or list of template arguments T. */
10780 static tree
10782 {
10794 {
10796 tree new_arg;
10801 {
10802 /* Substitute into an expansion expression. */
10806 /* Add to the expanded length adjustment the number of
10807 expanded arguments. We subtract one from this
10808 measurement, because the argument pack expression
10809 itself is already counted as 1 in
10810 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
10811 the argument pack is empty. */
10813 }
10815 {
10816 /* Substitute into each of the arguments. */
10822 new_arg,
10836 }
10837 }
10838 else
10847 }
10852 /* Make space for the expanded arguments coming from template
10853 argument packs. */
10855 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
10856 arguments for a member template.
10857 In that case each TREE_VEC in ORIG_T represents a level of template
10858 arguments, and ORIG_T won't carry any non defaulted argument count.
10859 It will rather be the nested TREE_VECs that will carry one.
10860 In other words, ORIG_T carries a non defaulted argument count only
10861 if it doesn't contain any nested TREE_VEC. */
10863 {
10867 }
10869 {
10873 {
10876 /* Now expand the template argument pack "in place". */
10879 }
10880 else
10881 {
10883 out++;
10884 }
10885 }
10888 }
10890 /* Return the result of substituting ARGS into the template parameters
10891 given by PARMS. If there are m levels of ARGS and m + n levels of
10892 PARMS, then the result will contain n levels of PARMS. For
10893 example, if PARMS is `template <class T> template <class U>
10894 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
10895 result will be `template <int*, double, class V>'. */
10897 static tree
10899 {
10903 /* When substituting into a template, we must set
10904 PROCESSING_TEMPLATE_DECL as the template parameters may be
10905 dependent if they are based on one-another, and the dependency
10906 predicates are short-circuit outside of templates. */
10913 {
10914 tree new_vec =
10919 {
10920 tree tuple;
10932 }
10938 }
10943 }
10945 /* Return the result of substituting ARGS into one template parameter
10946 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
10947 parameter and which TREE_PURPOSE is the default argument of the
10948 template parameter. */
10950 static tree
10952 {
10973 }
10975 /* Substitute the ARGS into the indicated aggregate (or enumeration)
10976 type T. If T is not an aggregate or enumeration type, it is
10977 handled as if by tsubst. IN_DECL is as for tsubst. If
10978 ENTERING_SCOPE is nonzero, T is the context for a template which
10979 we are presently tsubst'ing. Return the substituted value. */
10981 static tree
10983 tree args,
10984 tsubst_flags_t complain,
10985 tree in_decl,
10987 {
10992 {
10997 /* Else fall through. */
11001 {
11002 tree argvec;
11003 tree context;
11004 tree r;
11008 /* In "sizeof(X<I>)" we need to evaluate "I". */
11014 /* First, determine the context for the type we are looking
11015 up. */
11018 {
11021 /* If context is a nested class inside a class template,
11022 it may still need to be instantiated (c++/33959). */
11024 }
11026 /* Then, figure out what arguments are appropriate for the
11027 type we are trying to find. For example, given:
11029 template <class T> struct S;
11030 template <class T, class U> void f(T, U) { S<U> su; }
11032 and supposing that we are instantiating f<int, double>,
11033 then our ARGS will be {int, double}, but, when looking up
11034 S we only want {double}. */
11039 else
11040 {
11044 }
11050 }
11051 else
11052 /* This is not a template type, so there's nothing to do. */
11057 }
11058 }
11060 /* Substitute into the default argument ARG (a default argument for
11061 FN), which has the indicated TYPE. */
11063 tree
11065 {
11070 /* This can happen in invalid code. */
11074 /* This default argument came from a template. Instantiate the
11075 default argument here, not in tsubst. In the case of
11076 something like:
11078 template <class T>
11079 struct S {
11080 static T t();
11081 void f(T = t());
11082 };
11084 we must be careful to do name lookup in the scope of S<T>,
11085 rather than in the current class. */
11087 /* The "this" pointer is not valid in a default argument. */
11089 {
11094 }
11097 /* The default argument expression may cause implicitly defined
11098 member functions to be synthesized, which will result in garbage
11099 collection. We must treat this situation as if we were within
11100 the body of function so as to avoid collecting live data on the
11101 stack. */
11109 /* Restore the "this" pointer. */
11111 {
11114 }
11121 /* Make sure the default argument is reasonable. */
11127 }
11129 /* Substitute into all the default arguments for FN. */
11131 static void
11133 {
11134 tree arg;
11135 tree tmpl_args;
11139 /* If this function is not yet instantiated, we certainly don't need
11140 its default arguments. */
11143 /* Don't do this again for clones. */
11148 arg;
11154 complain);
11155 }
11157 /* Substitute the ARGS into the T, which is a _DECL. Return the
11158 result of the substitution. Issue error and warning messages under
11159 control of COMPLAIN. */
11161 static tree
11163 {
11164 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
11165 location_t saved_loc;
11170 /* Set the filename and linenumber to improve error-reporting. */
11175 {
11177 {
11178 /* We can get here when processing a member function template,
11179 member class template, or template template parameter. */
11181 tree spec;
11182 tree tmpl_args;
11183 tree full_args;
11186 {
11187 /* Template template parameter is treated here. */
11191 /* If we get a real template back, return it. This can happen in
11192 the context of most_specialized_partial_spec. */
11195 else
11196 /* The new TEMPLATE_DECL was built in
11197 reduce_template_parm_level. */
11200 }
11202 /* We might already have an instance of this template.
11203 The ARGS are for the surrounding class type, so the
11204 full args contain the tsubst'd args for the context,
11205 plus the innermost args from the template decl. */
11209 /* Because this is a template, the arguments will still be
11210 dependent, even after substitution. If
11211 PROCESSING_TEMPLATE_DECL is not set, the dependency
11212 predicates will short-circuit. */
11220 /* If this is a default template template argument,
11221 tsubst might not have changed anything. */
11228 {
11231 }
11233 /* Make a new template decl. It will be similar to the
11234 original, but will record the current template arguments.
11235 We also create a new function declaration, which is just
11236 like the old one, but points to this new template, rather
11237 than the old one. */
11242 // Build new template info linking to the original template decl.
11247 {
11248 tree new_type;
11256 /* For a partial specialization, we need to keep pointing to
11257 the primary template. */
11263 }
11264 else
11265 {
11266 tree new_decl;
11278 }
11284 /* The template parameters for this new template are all the
11285 template parameters for the old template, except the
11286 outermost level of parameters. */
11289 complain);
11295 /* Record this non-type partial instantiation. */
11299 }
11303 {
11304 tree ctx;
11307 tree gen_tmpl;
11308 tree type;
11313 /* Nobody should be tsubst'ing into non-template functions. */
11317 {
11318 tree spec;
11321 /* If T is not dependent, just return it. We have to
11322 increment PROCESSING_TEMPLATE_DECL because
11323 value_dependent_expression_p assumes that nothing is
11324 dependent when PROCESSING_TEMPLATE_DECL is zero. */
11331 /* Calculate the most general template of which R is a
11332 specialization, and the complete set of arguments used to
11333 specialize R. */
11336 (DECL_TEMPLATE_RESULT
11342 /* Check to see if we already have this specialization. */
11347 {
11350 }
11352 /* We can see more levels of arguments than parameters if
11353 there was a specialization of a member template, like
11354 this:
11356 template <class T> struct S { template <class U> void f(); }
11357 template <> template <class U> void S<int>::f(U);
11359 Here, we'll be substituting into the specialization,
11360 because that's where we can find the code we actually
11361 want to generate, but we'll have enough arguments for
11362 the most general template.
11364 We also deal with the peculiar case:
11366 template <class T> struct S {
11367 template <class U> friend void f();
11368 };
11369 template <class U> void f() {}
11370 template S<int>;
11371 template void f<double>();
11373 Here, the ARGS for the instantiation of will be {int,
11374 double}. But, we only need as many ARGS as there are
11375 levels of template parameters in CODE_PATTERN. We are
11376 careful not to get fooled into reducing the ARGS in
11377 situations like:
11379 template <class T> struct S { template <class U> void f(U); }
11380 template <class T> template <> void S<T>::f(int) {}
11382 which we can spot because the pattern will be a
11383 specialization in this case. */
11385 parms_depth =
11390 }
11391 else
11392 {
11393 /* This special case arises when we have something like this:
11395 template <class T> struct S {
11396 friend void f<int>(int, double);
11397 };
11399 Here, the DECL_TI_TEMPLATE for the friend declaration
11400 will be an IDENTIFIER_NODE. We are being called from
11401 tsubst_friend_function, and we want only to create a
11402 new decl (R) with appropriate types so that we can call
11403 determine_specialization. */
11405 }
11408 {
11411 else
11415 }
11416 else
11417 {
11420 }
11425 /* If we hit excessive deduction depth, the type is bogus even if
11426 it isn't error_mark_node, so don't build a decl. */
11430 /* We do NOT check for matching decls pushed separately at this
11431 point, as they may not represent instantiations of this
11432 template, and in any case are considered separate under the
11433 discrete model. */
11437 /* Clear out the mangled name and RTL for the instantiation. */
11440 /* Leave DECL_INITIAL set on deleted instantiations. */
11445 /* OpenMP UDRs have the only argument a reference to the declared
11446 type. We want to diagnose if the declared type is a reference,
11447 which is invalid, but as references to references are usually
11448 quietly merged, diagnose it here. */
11450 {
11451 tree argtype
11456 "reference type %qT in "
11460 argtype);
11461 }
11464 /* Type-conversion operator. Reconstruct the name, in
11465 case it's the name of one of the template's parameters. */
11475 /* If this is an instantiation of a function with internal
11476 linkage, we already know what object file linkage will be
11477 assigned to the instantiation. */
11486 /* We'll re-clone as appropriate in instantiate_template. */
11489 /* If we aren't complaining now, return on error before we register
11490 the specialization so that we'll complain eventually. */
11496 /* When instantiating a constrained member, substitute
11497 into the constraints to create a new constraint. */
11500 {
11503 }
11505 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
11506 this in the special friend case mentioned above where
11507 GEN_TMPL is NULL. */
11509 {
11514 tree new_r
11517 /* We instantiated this while substituting into
11518 the type earlier (template/friend54.C). */
11521 /* We're not supposed to instantiate default arguments
11522 until they are called, for a template. But, for a
11523 declaration like:
11525 template <class T> void f ()
11526 { extern void g(int i = T()); }
11528 we should do the substitution when the template is
11529 instantiated. We handle the member function case in
11530 instantiate_class_template since the default arguments
11531 might refer to other members of the class. */
11536 }
11537 else
11540 /* Copy the list of befriending classes. */
11544 {
11548 in_decl);
11549 }
11552 {
11558 /* If this is an instantiation of a member template, clone it.
11559 If it isn't, that'll be handled by
11560 clone_constructors_and_destructors. */
11563 }
11574 /* Possibly limit visibility based on template args. */
11577 {
11581 }
11589 }
11593 {
11601 {
11602 /* If there is a local specialization that isn't a
11603 parameter pack, it means that we're doing a "simple"
11604 substitution from inside tsubst_pack_expansion. Just
11605 return the local specialization (which will be a single
11606 parm). */
11613 /* Expand the TYPE_PACK_EXPANSION that provides the types for
11614 the parameters in this function parameter pack. */
11618 {
11621 /* Zero-length parameter packs are boring. Just substitute
11622 into the chain. */
11626 }
11627 else
11628 {
11629 /* All we did was update the type. Make a note of that. */
11632 }
11633 }
11635 /* Loop through all of the parameters we'll build. When T is
11636 a function parameter pack, LEN is the number of expanded
11637 types in EXPANDED_TYPES; otherwise, LEN is 1. */
11640 {
11647 /* We're on the Ith parameter of the function parameter
11648 pack. */
11649 {
11650 /* Get the Ith type. */
11653 /* Rename the parameter to include the index. */
11656 }
11658 /* We're dealing with a normal parameter. */
11666 {
11669 else
11672 }
11682 /* Keep track of the first new parameter we
11683 generate. That's what will be returned to the
11684 caller. */
11688 /* Build a proper chain of parameters when substituting
11689 into a function parameter pack. */
11692 }
11694 /* If cp_unevaluated_operand is set, we're just looking for a
11695 single dummy parameter, so don't keep going. */
11700 /* FIRST_R contains the start of the chain we've built. */
11702 }
11706 {
11713 {
11714 /* This field is a lambda capture pack. Return a TREE_VEC of
11715 the expanded fields to instantiate_class_template_1 and
11716 store them in the specializations hash table as a
11717 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
11721 {
11724 }
11725 else
11726 {
11727 /* All we did was update the type. Make a note of that. */
11730 }
11731 }
11734 {
11737 {
11741 }
11751 /* For bit-fields, DECL_INITIAL gives the number of bits. For
11752 non-bit-fields DECL_INITIAL is a non-static data member
11753 initializer, which gets deferred instantiation. */
11759 {
11760 /* Set up DECL_TEMPLATE_INFO so that we can get at the
11761 NSDMI in perform_member_init. Still set DECL_INITIAL
11762 so that we know there is one. */
11767 }
11768 /* We don't have to set DECL_CONTEXT here; it is set by
11769 finish_member_declaration. */
11777 }
11780 {
11788 }
11789 }
11793 /* We reach here only for member using decls. We also need to check
11794 uses_template_parms because DECL_DEPENDENT_P is not set for a
11795 using-declaration that designates a member of the current
11796 instantiation (c++/53549). */
11799 {
11806 else
11807 {
11810 }
11811 }
11812 else
11813 {
11816 }
11821 {
11824 tree spec;
11826 tree ctx;
11835 {
11836 /* If this is the canonical decl, we don't have to
11837 mess with instantiations, and often we can't (for
11838 typename, template type parms and such). Note that
11839 TYPE_NAME is not correct for the above test if
11840 we've copied the type for a typedef. */
11846 }
11848 /* Check to see if we already have the specialization we
11849 need. */
11852 {
11853 /* T is a static data member or namespace-scope entity.
11854 We have to substitute into namespace-scope variables
11855 (not just variable templates) because of cases like:
11857 template <class T> void f() { extern T t; }
11859 where the entity referenced is not known until
11860 instantiation time. */
11864 {
11866 complain,
11868 /* If CTX is unchanged, then T is in fact the
11869 specialization we want. That situation occurs when
11870 referencing a static data member within in its own
11871 class. We can use pointer equality, rather than
11872 same_type_p, because DECL_CONTEXT is always
11873 canonical... */
11875 /* ... unless T is a member template; in which
11876 case our caller can be willing to create a
11877 specialization of that template represented
11878 by T. */
11882 }
11885 {
11890 argvec = (coerce_innermost_template_parms
11898 }
11899 }
11900 else
11901 {
11902 /* A local variable. */
11904 /* Subsequent calls to pushdecl will fill this in. */
11907 }
11908 /* If we already have the specialization we need, there is
11909 nothing more to do. */
11911 {
11914 }
11916 /* Create a new node for the specialization we need. */
11919 {
11922 else
11929 }
11931 {
11932 /* Even if the original location is out of scope, the
11933 newly substituted one is not. */
11940 {
11941 /* It may seem that this case cannot occur, since:
11943 typedef void f();
11944 void g() { f x; }
11946 declares a function, not a variable. However:
11948 typedef void f();
11949 template <typename T> void g() { T t; }
11950 template void g<f>();
11952 is an attempt to declare a variable with function
11953 type. */
11955 /* R is not yet sufficiently initialized, so we
11956 just use its name. */
11959 }
11961 /* Wait until cp_finish_decl to set this again, to handle
11962 circular dependency (template/instantiate6.C). */
11967 {
11972 {
11975 }
11977 }
11981 }
11987 /* Clear out the mangled name and RTL for the instantiation. */
11991 /* The initializer must not be expanded until it is required;
11992 see [temp.inst]. */
11998 {
11999 /* Possibly limit visibility based on template args. */
12002 {
12006 }
12008 }
12011 {
12012 /* A static data member declaration is always marked
12013 external when it is declared in-class, even if an
12014 initializer is present. We mimic the non-template
12015 processing here. */
12023 }
12033 /* Preserve a typedef that names a type. */
12035 {
12039 /* An alias template specialization can be dependent
12040 even if its underlying type is not. */
12042 }
12045 }
12050 }
12051 #undef RETURN
12053 out:
12054 /* Restore the file and line information. */
12058 }
12060 /* Substitute into the ARG_TYPES of a function type.
12061 If END is a TREE_CHAIN, leave it and any following types
12062 un-substituted. */
12064 static tree
12066 tree args,
12067 tree end,
12068 tsubst_flags_t complain,
12069 tree in_decl)
12070 {
12071 tree remaining_arg_types;
12075 tree default_arg;
12086 {
12087 /* For a pack expansion, perform substitution on the
12088 entire expression. Later on, we'll handle the arguments
12089 one-by-one. */
12094 /* So that we'll spin through the parameters, one by one. */
12096 else
12097 {
12098 /* We only partially substituted into the parameter
12099 pack. Our type is TYPE_PACK_EXPANSION. */
12102 }
12103 }
12116 {
12118 {
12122 }
12124 }
12125 /* DR 657. */
12129 /* Do array-to-pointer, function-to-pointer conversion, and ignore
12130 top-level qualifiers as required. */
12133 /* We do not substitute into default arguments here. The standard
12134 mandates that they be instantiated only when needed, which is
12135 done in build_over_call. */
12139 {
12140 /* We've instantiated a template before its default arguments
12141 have been parsed. This can happen for a nested template
12142 class, and is not an error unless we require the default
12143 argument in a call of this function. */
12144 remaining_arg_types =
12147 }
12148 else
12149 remaining_arg_types =
12151 }
12154 }
12156 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
12157 *not* handle the exception-specification for FNTYPE, because the
12158 initial substitution of explicitly provided template parameters
12159 during argument deduction forbids substitution into the
12160 exception-specification:
12162 [temp.deduct]
12164 All references in the function type of the function template to the
12165 corresponding template parameters are replaced by the specified tem-
12166 plate argument values. If a substitution in a template parameter or
12167 in the function type of the function template results in an invalid
12168 type, type deduction fails. [Note: The equivalent substitution in
12169 exception specifications is done only when the function is instanti-
12170 ated, at which point a program is ill-formed if the substitution
12171 results in an invalid type.] */
12173 static tree
12175 tree args,
12176 tsubst_flags_t complain,
12177 tree in_decl)
12178 {
12179 tree return_type;
12181 tree fntype;
12183 /* The TYPE_CONTEXT is not used for function/method types. */
12186 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
12187 failure. */
12191 {
12192 /* Substitute the argument types. */
12204 {
12205 /* DR 1207: 'this' is in scope in the trailing return type. */
12207 }
12209 /* Substitute the return type. */
12213 {
12216 }
12217 }
12218 else
12219 /* Substitute the return type. */
12224 /* DR 486 clarifies that creation of a function type with an
12225 invalid return type is a deduction failure. */
12228 {
12230 {
12233 else
12235 }
12237 }
12238 /* And DR 657. */
12243 {
12244 /* Substitute the argument types. */
12249 }
12251 /* Construct a new type node and return it. */
12253 {
12258 }
12259 else
12260 {
12262 /* Don't pick up extra function qualifiers from the basetype. */
12265 {
12266 /* [temp.deduct]
12268 Type deduction may fail for any of the following
12269 reasons:
12271 -- Attempting to create "pointer to member of T" when T
12272 is not a class type. */
12275 r);
12277 }
12282 }
12289 }
12291 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
12292 ARGS into that specification, and return the substituted
12293 specification. If there is no specification, return NULL_TREE. */
12295 static tree
12297 tree args,
12298 tsubst_flags_t complain,
12299 tree in_decl,
12301 {
12302 tree specs;
12303 tree new_specs;
12308 {
12309 /* A noexcept-specifier. */
12314 {
12315 /* Defer instantiation of noexcept-specifiers to avoid
12316 excessive instantiations (c++/49107). */
12319 {
12320 /* We already partially instantiated this member template,
12321 so combine the new args with the old. */
12326 }
12327 else
12328 {
12331 }
12332 }
12333 else
12334 new_specs = tsubst_copy_and_build
12338 }
12340 {
12343 else
12345 {
12346 tree spec;
12351 {
12352 /* Expand the pack expansion type. */
12355 in_decl);
12361 else
12362 {
12363 /* We're substituting into a member template, so
12364 we got a TYPE_PACK_EXPANSION back. Add that
12365 expansion and move on. */
12369 expanded_specs,
12370 complain);
12373 }
12374 }
12377 {
12380 else
12385 complain);
12386 }
12389 }
12390 }
12392 }
12394 /* Take the tree structure T and replace template parameters used
12395 therein with the argument vector ARGS. IN_DECL is an associated
12396 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
12397 Issue error and warning messages under control of COMPLAIN. Note
12398 that we must be relatively non-tolerant of extensions here, in
12399 order to preserve conformance; if we allow substitutions that
12400 should not be allowed, we may allow argument deductions that should
12401 not succeed, and therefore report ambiguous overload situations
12402 where there are none. In theory, we could allow the substitution,
12403 but indicate that it should have failed, and allow our caller to
12404 make sure that the right thing happens, but we don't try to do this
12405 yet.
12407 This function is used for dealing with types, decls and the like;
12408 for expressions, use tsubst_expr or tsubst_copy. */
12410 tree
12412 {
12435 else
12440 /* Reuse typedefs. We need to do this to handle dependent attributes,
12441 such as attribute aligned. */
12444 {
12448 {
12449 /* DECL represents an alias template and we want to
12450 instantiate it. */
12454 }
12458 {
12462 }
12467 else
12468 /* The typedef is from a non-template context. */
12472 {
12474 r = cp_build_qualified_type_real
12478 }
12479 else
12480 {
12481 /* We don't have an instantiation yet, so drop the typedef. */
12486 }
12487 }
12500 {
12526 {
12532 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
12533 needed. */
12539 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
12540 with TREE_SIDE_EFFECTS that indicates this is not an integral
12541 constant expression. */
12544 {
12547 }
12550 }
12556 {
12562 /* Early in template argument deduction substitution, we don't
12563 want to reduce the level of 'auto', or it will be confused
12564 with a normal template parm in subsequent deduction. */
12576 {
12580 {
12581 /* See through ARGUMENT_PACK_SELECT arguments. */
12583 /* If the selected argument is an expansion E, that most
12584 likely means we were called from
12585 gen_elem_of_pack_expansion_instantiation during the
12586 substituting of pack an argument pack (which Ith
12587 element is a pack expansion, where I is
12588 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
12589 In this case, the Ith element resulting from this
12590 substituting is going to be a pack expansion, which
12591 pattern is the pattern of E. Let's return the
12592 pattern of E, and
12593 gen_elem_of_pack_expansion_instantiation will
12594 build the resulting pack expansion from it. */
12596 {
12597 /* Make sure we aren't throwing away arg info. */
12600 }
12601 }
12602 }
12607 {
12609 /* If ARG is an argument pack, we don't actually want to
12610 perform a substitution here, because substitutions
12611 for argument packs are only done
12612 element-by-element. We can get to this point when
12613 substituting the type of a non-type template
12614 parameter pack, when that type actually contains
12615 template parameter packs from an outer template, e.g.,
12617 template<typename... Types> struct A {
12618 template<Types... Values> struct B { };
12619 }; */
12623 {
12629 return cp_build_qualified_type_real
12631 }
12633 {
12634 /* We are processing a type constructed from a
12635 template template parameter. */
12646 /* Consider this code:
12648 template <template <class> class Template>
12649 struct Internal {
12650 template <class Arg> using Bind = Template<Arg>;
12651 };
12653 template <template <class> class Template, class Arg>
12654 using Instantiate = Template<Arg>; //#0
12656 template <template <class> class Template,
12657 class Argument>
12658 using Bind =
12659 Instantiate<Internal<Template>::template Bind,
12660 Argument>; //#1
12662 When #1 is parsed, the
12663 BOUND_TEMPLATE_TEMPLATE_PARM representing the
12664 parameter `Template' in #0 matches the
12665 UNBOUND_CLASS_TEMPLATE representing the argument
12666 `Internal<Template>::template Bind'; We then want
12667 to assemble the type `Bind<Argument>' that can't
12668 be fully created right now, because
12669 `Internal<Template>' not being complete, the Bind
12670 template cannot be looked up in that context. So
12671 we need to "store" `Bind<Argument>' for later
12672 when the context of Bind becomes complete. Let's
12673 store that in a TYPENAME_TYPE. */
12677 argvec),
12678 typename_type,
12679 complain);
12681 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
12682 are resolving nested-types in the signature of a
12683 member function templates. Otherwise ARG is a
12684 TEMPLATE_DECL and is the real template to be
12685 instantiated. */
12693 complain);
12694 return cp_build_qualified_type_real
12696 }
12697 else
12698 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
12700 }
12703 /* This can happen during the attempted tsubst'ing in
12704 unify. This means that we don't yet have any information
12705 about the template parameter in question. */
12708 /* If we get here, we must have been looking at a parm for a
12709 more deeply nested template. Make a new version of this
12710 template parameter, but with a lower level. */
12712 {
12717 {
12719 r = cp_build_qualified_type_real
12723 }
12730 /* Break infinite recursion when substituting the constraints
12732 else
12733 {
12744 /* We have reduced the level of the template
12745 template parameter, but not the levels of its
12746 template parameters, so canonical_type_parameter
12747 will not be able to find the canonical template
12748 template parameter for this level. Thus, we
12749 require structural equality checking to compare
12750 TEMPLATE_TEMPLATE_PARMs. */
12754 else
12757 /* Propagate constraints on placeholders. */
12764 {
12772 }
12773 }
12782 }
12785 }
12788 {
12796 {
12800 }
12803 {
12807 }
12810 {
12814 }
12820 }
12823 /* We should never be tsubsting a binfo. */
12827 /* A vector of template arguments. */
12833 {
12837 /* [temp.deduct]
12839 Type deduction may fail for any of the following
12840 reasons:
12842 -- Attempting to create a pointer to reference type.
12843 -- Attempting to create a reference to a reference type or
12844 a reference to void.
12846 Core issue 106 says that creating a reference to a reference
12847 during instantiation is no longer a cause for failure. We
12848 only enforce this check in strict C++98 mode. */
12852 {
12855 /* We keep track of the last time we issued this error
12856 message to avoid spewing a ton of messages during a
12857 single bad template instantiation. */
12860 {
12865 else
12868 }
12871 }
12875 {
12877 {
12880 type);
12881 else
12883 type);
12884 }
12886 }
12888 {
12892 }
12894 /* In C++0x, during template argument substitution, when there is an
12895 attempt to create a reference to a reference type, reference
12896 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
12898 "If a template-argument for a template-parameter T names a type
12899 that is a reference to a type A, an attempt to create the type
12900 'lvalue reference to cv T' creates the type 'lvalue reference to
12901 A,' while an attempt to create the type type rvalue reference to
12902 cv T' creates the type T"
12903 */
12904 r = cp_build_reference_type
12907 else
12912 /* Will this ever be needed for TYPE_..._TO values? */
12916 }
12918 {
12921 {
12922 /* [temp.deduct]
12924 Type deduction may fail for any of the following
12925 reasons:
12927 -- Attempting to create "pointer to member of T" when T
12928 is not a class type. */
12932 }
12934 {
12938 }
12940 {
12944 }
12947 {
12948 /* The type of the implicit object parameter gets its
12949 cv-qualifiers from the FUNCTION_TYPE. */
12950 tree memptr;
12951 tree method_type
12956 complain);
12957 }
12958 else
12961 complain);
12962 }
12965 {
12966 tree fntype;
12967 tree specs;
12972 /* Substitute the exception specification. */
12980 }
12982 {
12987 /* As an optimization, we avoid regenerating the array type if
12988 it will obviously be the same as T. */
12992 /* These checks should match the ones in create_array_type_for_decl.
12994 [temp.deduct]
12996 The deduction may fail for any of the following reasons:
12998 -- Attempting to create an array with an element type that
12999 is void, a function type, or a reference type, or [DR337]
13000 an abstract class type. */
13006 {
13010 }
13018 {
13021 }
13024 }
13027 {
13037 {
13041 }
13043 {
13044 /* Normally, make_typename_type does not require that the CTX
13045 have complete type in order to allow things like:
13047 template <class T> struct S { typename S<T>::X Y; };
13049 But, such constructs have already been resolved by this
13050 point, so here CTX really should have complete type, unless
13051 it's a partial instantiation. */
13054 {
13058 }
13059 }
13066 {
13069 }
13072 {
13074 {
13078 else
13080 }
13082 {
13086 else
13088 }
13089 }
13091 return cp_build_qualified_type_real
13093 }
13096 {
13108 }
13111 {
13112 tree type;
13128 complain);
13129 }
13132 {
13133 tree type;
13151 else
13152 {
13156 /* In a template ~id could be either a complement expression
13157 or an unqualified-id naming a destructor; if instantiating
13158 it produces an expression, it's not an id-expression or
13159 member access. */
13162 }
13167 }
13170 {
13174 }
13178 {
13180 tree packed_out =
13182 args,
13183 complain,
13184 in_decl);
13187 /* For template nontype argument packs, also substitute into
13188 the type. */
13193 }
13209 /* We should use one of the expression tsubsts for these codes. */
13215 }
13216 }
13218 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
13219 type of the expression on the left-hand side of the "." or "->"
13220 operator. */
13222 static tree
13225 {
13226 tree name;
13227 tree qualifying_scope;
13228 tree fns;
13229 tree optype;
13234 /* A baselink indicates a function from a base class. Both the
13235 BASELINK_ACCESS_BINFO and the base class referenced may
13236 indicate bases of the template class, rather than the
13237 instantiated class. In addition, lookups that were not
13238 ambiguous before may be ambiguous now. Therefore, we perform
13239 the lookup again. */
13246 {
13253 }
13261 /* If lookup found a single function, mark it as used at this
13262 point. (If it lookup found multiple functions the one selected
13263 later by overload resolution will be marked as used at that
13264 point.) */
13271 /* Add back the template arguments, if present. */
13276 template_args);
13277 /* Update the conversion operator type. */
13285 qualifying_scope,
13286 object_type);
13288 }
13290 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
13291 true if the qualified-id will be a postfix-expression in-and-of
13292 itself; false if more of the postfix-expression follows the
13293 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
13294 of "&". */
13296 static tree
13300 {
13301 tree expr;
13302 tree scope;
13303 tree name;
13305 tree template_args;
13310 /* Figure out what name to look up. */
13313 {
13321 }
13322 else
13323 {
13326 }
13328 /* Substitute into the qualifying scope. When there are no ARGS, we
13329 are just trying to simplify a non-dependent expression. In that
13330 case the qualifying scope may be dependent, and, in any case,
13331 substituting will not help. */
13334 {
13337 }
13338 else
13342 {
13347 }
13350 {
13352 {
13353 /* A BIT_NOT_EXPR is used to represent a destructor. */
13355 {
13359 }
13360 else
13363 }
13364 else
13368 {
13370 {
13374 }
13376 }
13377 }
13380 {
13382 scope);
13383 /* Remember that there was a reference to this entity. */
13386 }
13389 {
13395 }
13404 {
13405 expr = (adjust_result_of_qualified_name_lookup
13407 expr = (finish_qualified_id_expr
13411 }
13413 /* Expressions do not generally have reference type. */
13415 /* However, if we're about to form a pointer-to-member, we just
13416 want the referenced member referenced. */
13421 }
13423 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
13424 initializer, DECL is the substituted VAR_DECL. Other arguments are as
13425 for tsubst. */
13427 static tree
13430 {
13437 {
13438 /* If we had an initializer but it
13439 instantiated to nothing,
13440 value-initialize the object. This will
13441 only occur when the initializer was a
13442 pack expansion where the parameter packs
13443 used in that expansion were of length
13444 zero. */
13446 complain);
13449 }
13452 }
13454 /* Like tsubst, but deals with expressions. This function just replaces
13455 template parms; to finish processing the resultant expression, use
13456 tsubst_copy_and_build or tsubst_expr. */
13458 static tree
13460 {
13462 tree r;
13470 {
13475 {
13476 /* We get here for a use of 'this' in an NSDMI. */
13478 && current_function_decl
13482 /* This can happen for a parameter name used later in a function
13483 declaration (such as in a late-specified return type). Just
13484 make a dummy decl, since it's only used for its type. */
13487 /* Give it the template pattern as its context; its true context
13488 hasn't been instantiated yet and this is good enough for
13489 mangling. */
13491 }
13500 {
13501 tree enum_type;
13502 tree v;
13506 /* There is no need to substitute into namespace-scope
13507 enumerators. */
13510 /* If ARGS is NULL, then T is known to be non-dependent. */
13514 /* Unfortunately, we cannot just call lookup_name here.
13515 Consider:
13517 template <int I> int f() {
13518 enum E { a = I };
13519 struct S { void g() { E e = a; } };
13520 };
13522 When we instantiate f<7>::S::g(), say, lookup_name is not
13523 clever enough to find f<7>::a. */
13524 enum_type
13534 /* We didn't find the name. That should never happen; if
13535 name-lookup found it during preliminary parsing, we
13536 should find it again here during instantiation. */
13538 }
13543 {
13544 /* Check for a local specialization set up by
13545 tsubst_pack_expansion. */
13547 {
13551 }
13553 /* When retrieving a capture pack from a generic lambda, remove the
13554 lambda call op's own template argument list from ARGS. Only the
13555 template arguments active for the closure type should be used to
13556 retrieve the pack specialization. */
13562 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
13563 tsubst_decl put in the hash table. */
13565 }
13568 {
13569 tree ctx;
13574 {
13577 {
13581 }
13583 }
13584 }
13593 {
13596 {
13597 /* First try name lookup to find the instantiation. */
13600 {
13601 /* Make sure that the one we found is the one we want. */
13606 }
13610 else
13611 {
13612 /* This can happen for a variable used in a
13613 late-specified return type of a local lambda, or for a
13614 local static or constant. Building a new VAR_DECL
13615 should be OK in all those cases. */
13618 {
13619 /* We can't call cp_finish_decl, so handle the
13620 initializer by hand. */
13631 }
13636 {
13639 at_eof);
13640 else
13642 }
13643 }
13644 /* Remember this for subsequent uses. */
13647 }
13648 }
13649 else
13659 /* An OVERLOAD will always be a non-dependent overload set; an
13660 overload set from function scope will just be represented with an
13661 IDENTIFIER_NODE, and from class scope with a BASELINK. */
13677 {
13678 /* Template template argument like the following example need
13679 special treatment:
13681 template <template <class> class TT> struct C {};
13682 template <class T> struct D {
13683 template <class U> struct E {};
13684 C<E> c; // #1
13685 };
13686 D<int> d; // #2
13688 We are processing the template argument `E' in #1 for
13689 the template instantiation #2. Originally, `E' is a
13690 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
13691 have to substitute this with one having context `D<int>'. */
13695 }
13696 else
13697 /* Ordinary template template argument. */
13708 {
13712 }
13716 {
13726 /* We only want to compute the number of arguments. */
13740 {
13747 else
13750 }
13751 else
13753 }
13755 {
13763 }
13764 /* Fall through */
13780 {
13784 }
13787 {
13788 tree object;
13789 tree name;
13794 {
13798 }
13801 {
13811 }
13816 in_decl);
13817 else
13820 }
13858 {
13862 }
13865 {
13870 }
13873 {
13877 }
13880 {
13888 }
13894 {
13901 }
13904 {
13911 }
13914 {
13921 }
13924 {
13925 /* Substituted template arguments */
13934 }
13937 {
13957 }
13982 /* Fall through. */
13985 {
13988 }
13989 else
13993 /* This is handled by tsubst_copy_and_build. */
13997 {
14001 }
14004 /* We shouldn't have built any of these during initial template
14005 generation. Instead, they should be built during instantiation
14006 in response to the saved STMT_IS_FULL_EXPR_P setting. */
14010 {
14020 }
14038 {
14039 /* Instantiate any typedefs in the type. */
14044 }
14047 /* These can sometimes show up in a partial instantiation, but never
14048 involve template parms. */
14053 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
14056 }
14057 }
14059 /* Helper function for tsubst_omp_clauses, used for instantiation of
14060 OMP_CLAUSE_DECL of clauses that handles also OpenMP array sections
14061 represented with TREE_LIST. */
14063 static tree
14065 tree in_decl)
14066 {
14068 {
14069 tree low_bound
14075 in_decl);
14081 }
14083 }
14085 /* Like tsubst_copy, but specifically for OpenMP clauses. */
14087 static tree
14090 {
14094 {
14100 {
14103 {
14109 }
14110 /* FALLTHRU */
14126 in_decl);
14145 {
14148 {
14155 }
14156 else
14158 }
14185 }
14186 }
14192 }
14194 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
14196 static tree
14198 tree in_decl)
14199 {
14200 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
14220 {
14223 else
14224 {
14228 }
14229 }
14234 #undef RECUR
14235 }
14237 /* Substitute one OMP_FOR iterator. */
14239 static void
14244 {
14245 #define RECUR(NODE) \
14246 tsubst_expr ((NODE), args, complain, in_decl, \
14247 integral_constant_expression_p)
14256 {
14257 /* We need to jump through some hoops to handle declarations in the
14258 for-init-statement, since we might need to handle auto deduction,
14259 but we need to keep control of initialization. */
14263 }
14264 else
14276 {
14278 {
14279 /* Declare the variable, but don't let that initialize it. */
14284 }
14289 {
14294 }
14295 else
14302 }
14305 {
14306 /* Declare and initialize the variable. */
14309 }
14311 {
14312 tree c;
14314 {
14325 }
14327 {
14332 {
14335 }
14336 }
14337 }
14340 {
14344 }
14345 else
14349 {
14360 {
14368 }
14369 else
14375 {
14381 }
14385 {
14393 }
14394 else
14400 }
14406 #undef RECUR
14407 }
14409 /* Like tsubst_copy for expressions, etc. but also does semantic
14410 processing. */
14412 tree
14415 {
14416 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14417 #define RECUR(NODE) \
14418 tsubst_expr ((NODE), args, complain, in_decl, \
14419 integral_constant_expression_p)
14422 tree r;
14423 location_t loc;
14435 {
14437 {
14438 tree_stmt_iterator i;
14442 }
14457 else
14466 {
14468 tree init;
14474 {
14477 tree decl;
14485 else
14487 }
14489 {
14490 /* Don't build up decls for a variadic capture proxy, we'll
14491 instantiate the elements directly as needed. */
14493 }
14494 else
14495 {
14499 {
14500 /* By marking the declaration as instantiated, we avoid
14501 trying to instantiate it. Since instantiate_decl can't
14502 handle local variables, and since we've already done
14503 all that needs to be done, that's the right thing to
14504 do. */
14509 /* Anonymous aggregates are a special case. */
14512 {
14515 {
14519 }
14521 }
14527 {
14532 }
14533 else
14534 {
14539 {
14540 /* For __PRETTY_FUNCTION__ we have to adjust the
14541 initializer. */
14545 }
14546 else
14550 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
14553 }
14554 }
14555 }
14558 }
14573 {
14583 }
14610 {
14614 }
14622 else
14630 else
14651 {
14655 }
14659 {
14661 tree label;
14666 }
14672 /* Computed goto's must be tsubst'd into. On the other hand,
14673 non-computed gotos must not be; the identifier in question
14674 will have no binding. */
14676 else
14682 {
14698 }
14703 {
14708 }
14709 else
14710 {
14715 else
14722 else
14728 else
14730 }
14734 {
14738 {
14740 /* Prevent instantiate_decl from trying to instantiate
14741 this variable. We've already done all that needs to be
14742 done. */
14745 }
14750 }
14756 {
14757 /* Local classes are not independent templates; they are
14758 instantiated along with their containing function. And this
14759 way we don't have to deal with pushing out of one local class
14760 to instantiate a member of another local class. */
14761 tree fn;
14762 /* Closures are handled by the LAMBDA_EXPR. */
14768 }
14772 {
14773 tree condition;
14776 condition =
14778 args,
14787 }
14812 {
14821 {
14826 }
14838 integral_constant_expression_p);
14847 else
14848 {
14856 }
14859 }
14918 {
14923 {
14926 }
14932 }
14933 else
14934 {
14941 {
14944 }
14947 {
14952 {
14955 }
14961 }
14962 else
14963 {
14967 }
14970 }
14974 {
14980 {
14984 {
14989 }
14993 }
14994 else
14995 {
15000 }
15001 }
15005 {
15009 }
15029 /* If the first operand was a statement, we're done with it. */
15033 complain));
15045 integral_constant_expression_p));
15046 }
15049 out:
15052 #undef RECUR
15053 #undef RETURN
15054 }
15056 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
15057 function. For description of the body see comment above
15058 cp_parser_omp_declare_reduction_exprs. */
15060 static void
15062 {
15068 tree_stmt_iterator tsi;
15079 {
15098 }
15100 {
15120 }
15121 }
15123 /* T is a postfix-expression that is not being used in a function
15124 call. Return the substituted version of T. */
15126 static tree
15128 tsubst_flags_t complain,
15129 tree in_decl)
15130 {
15134 else
15140 }
15142 /* Like tsubst but deals with expressions and performs semantic
15143 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
15145 tree
15147 tree args,
15148 tsubst_flags_t complain,
15149 tree in_decl,
15152 {
15153 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
15154 #define RECUR(NODE) \
15155 tsubst_copy_and_build (NODE, args, complain, in_decl, \
15157 integral_constant_expression_p)
15160 location_t loc;
15169 /* N3276 decltype magic only applies to calls at the top level or on the
15170 right side of a comma. */
15175 {
15178 /* Fall through. */
15180 {
15181 tree decl;
15182 cp_id_kind idk;
15187 {
15190 }
15192 /* Look up the name. */
15195 /* By convention, expressions use ERROR_MARK_NODE to indicate
15196 failure, not NULL_TREE. */
15202 integral_constant_expression_p,
15210 input_location);
15214 {
15218 }
15220 }
15223 {
15224 tree object;
15234 {
15237 {
15240 }
15242 }
15245 {
15248 }
15249 else
15256 else
15258 }
15261 {
15265 {
15266 /* A type conversion to reference type will be enclosed in
15267 such an indirect ref, but the substitution of the cast
15268 will have also added such an indirect ref. */
15271 }
15272 else
15276 }
15279 {
15283 }
15286 {
15293 flags));
15294 }
15297 {
15301 }
15308 {
15309 tree type;
15315 {
15320 }
15326 {
15344 }
15347 }
15381 else
15383 in_decl);
15418 {
15425 tree r = build_x_binary_op
15427 op0,
15429 ? ERROR_MARK
15431 op1,
15433 ? ERROR_MARK
15441 }
15444 {
15448 }
15461 {
15470 }
15474 /* Fall through */
15477 {
15478 tree r;
15484 {
15485 /* When there are no ARGS, we are trying to evaluate a
15486 non-dependent expression from the parser. Trying to do
15487 the substitutions may not work. */
15490 }
15491 else
15492 {
15497 else
15500 /*integral_constant_expression_p=*/
15504 }
15508 else
15512 {
15514 {
15516 {
15520 }
15521 else
15525 }
15527 }
15529 }
15532 {
15542 }
15558 {
15562 tree r = build_x_modify_expr
15565 /* TREE_NO_WARNING must be set if either the expression was
15566 parenthesized or it uses an operator such as >>= rather
15567 than plain assignment. In the former case, it was already
15568 set and must be copied. In the latter case,
15569 build_x_modify_expr sets it and it must not be reset
15570 here. */
15575 }
15580 /* Remember that there was a reference to this entity. */
15587 {
15592 tree ret;
15596 else
15597 {
15601 }
15603 /* If there was an initializer in the original tree, but it
15604 instantiated to an empty list, then we should pass a
15605 non-NULL empty vector to tell build_new that it was an
15606 empty initializer() rather than no initializer. This can
15607 only happen when the initializer is a pack expansion whose
15608 parameter packs are of length zero. */
15611 else
15612 {
15616 else
15617 {
15620 }
15621 }
15627 complain);
15635 }
15638 {
15644 complain));
15645 }
15648 {
15652 integral_constant_expression_p);
15654 op0,
15657 }
15660 {
15661 tree function;
15666 tree ret;
15669 /* When we parsed the expression, we determined whether or
15670 not Koenig lookup should be performed. */
15673 {
15678 }
15680 {
15681 /* Do nothing; calling tsubst_copy_and_build on an identifier
15682 would incorrectly perform unqualified lookup again.
15684 Note that we can also have an IDENTIFIER_NODE if the earlier
15685 unqualified lookup found a member function; in that case
15686 koenig_p will be false and we do want to do the lookup
15687 again to find the instantiated member function.
15689 FIXME but doing that causes c++/15272, so we need to stop
15690 using IDENTIFIER_NODE in that situation. */
15692 }
15693 else
15694 {
15696 {
15702 }
15703 else
15708 /* Avoid error about taking the address of a constructor. */
15712 in_decl,
15714 integral_constant_expression_p);
15718 }
15723 {
15728 else
15729 {
15730 /* Expand the pack expansion and push each entry onto
15731 CALL_ARGS. */
15734 {
15739 {
15744 }
15745 }
15746 else
15747 {
15748 /* A partial substitution. Add one entry. */
15750 }
15751 }
15752 }
15754 /* We do not perform argument-dependent lookup if normal
15755 lookup finds a non-function, in accordance with the
15756 expected resolution of DR 218. */
15759 /* If lookup found a member function, the Koenig lookup is
15760 not appropriate, even if an unqualified-name was used
15761 to denote the function. */
15764 /* Only do this when substitution turns a dependent call
15765 into a non-dependent call. */
15772 {
15774 {
15775 /* For backwards compatibility and good diagnostics, try
15776 the unqualified lookup again if we aren't in SFINAE
15777 context. */
15778 tree unq = (tsubst_copy_and_build
15780 integral_constant_expression_p));
15785 {
15794 "%qD was not declared in this scope, "
15795 "and no declarations were found by "
15796 "argument-dependent lookup at the point "
15798 {
15802 {
15804 input_location);
15806 "declarations in dependent base %qT are "
15812 else
15816 }
15817 else
15819 "%qD declared here, later in the "
15821 }
15823 }
15824 }
15826 {
15831 }
15832 }
15834 /* Remember that there was a reference to this entity. */
15839 /* Put back tf_decltype for the actual call. */
15844 complain);
15846 {
15861 complain);
15862 else
15863 ret = (build_new_method_call
15868 complain));
15869 }
15870 else
15873 koenig_p,
15874 complain);
15879 }
15882 {
15888 {
15890 {
15895 }
15896 else
15897 {
15902 }
15904 }
15905 else
15906 {
15909 }
15913 }
15916 {
15921 input_location));
15922 }
15925 {
15933 {
15934 /* We have pack expansions, so expand those and
15935 create a new list out of it. */
15938 tree chain;
15941 /* Expand the argument expressions. */
15949 /* Build the rest of the list. */
15954 /* Determine the number of arguments. */
15956 {
15959 }
15962 else
15963 {
15964 /* Since we only performed a partial substitution into
15965 the argument pack, we only RETURN (a single list
15966 node. */
15973 }
15975 /* Convert the argument vectors into a TREE_LIST */
15978 {
15979 /* Grab the Ith values. */
15980 i--;
15983 value
15987 /* Build the list (backwards). */
15989 }
15992 }
16008 }
16011 {
16012 tree object;
16013 tree object_type;
16014 tree member;
16015 tree r;
16019 /* Remember that there was a reference to this entity. */
16030 else
16038 {
16040 {
16045 {
16048 }
16050 {
16055 }
16056 }
16057 }
16060 {
16061 /* Lookup the template functions now that we know what the
16062 scope is. */
16070 {
16073 args);
16074 member = (adjust_result_of_qualified_name_lookup
16076 object_type));
16077 }
16078 else
16079 {
16081 input_location);
16083 }
16084 }
16088 {
16090 {
16094 else
16097 }
16099 }
16101 {
16106 }
16110 complain);
16114 }
16121 {
16129 tree r;
16134 /* digest_init will do the wrong thing if we let it. */
16138 /* We do not want to process the index of aggregate
16139 initializers as they are identifier nodes which will be
16140 looked up by digest_init. */
16146 {
16148 /* An identifier index is looked up in the type
16149 being initialized, not the current scope. */
16154 {
16155 /* Substitute into the pack expansion. */
16157 in_decl);
16161 ;
16163 /* Just move the argument into place. */
16165 else
16166 {
16167 /* Update the length of the final CONSTRUCTOR
16168 arguments vector, and note that we will need to
16169 copy.*/
16172 }
16173 }
16174 else
16176 }
16179 {
16184 {
16186 {
16191 }
16192 else
16194 }
16195 }
16205 }
16208 {
16211 {
16214 }
16215 else
16216 {
16219 }
16220 }
16226 {
16227 /* We don't build decls for an instantiation of a
16228 variadic capture proxy, we instantiate the elements
16229 when needed. */
16232 }
16233 /* Fall through */
16236 {
16238 /* ??? We're doing a subset of finish_id_expression here. */
16240 && !processing_template_decl
16241 && !cp_unevaluated_operand
16244 {
16246 /* Replace an evaluated use of the thread_local variable with
16247 a call to its wrapper. */
16249 }
16251 {
16255 }
16258 /* If the original type was a reference, we'll be wrapped in
16259 the appropriate INDIRECT_REF. */
16262 }
16265 {
16269 }
16276 {
16287 }
16290 {
16296 integral_constant_expression_p);
16300 /* If the resulting list of expression statement is empty,
16301 fold it further into void_node. */
16306 }
16309 {
16323 /* For a function scope, we want to use tsubst so that we don't
16324 complain about referring to an auto function before its return
16325 type has been deduced. Otherwise, we want to use tsubst_copy so
16326 that we look up the existing field/parameter/variable rather
16327 than build a new one. */
16332 {
16333 /* Look up the parameter we want directly, as tsubst_copy
16334 doesn't do what we need. */
16340 /* FIXME Work around the parm not having DECL_CONTEXT set. */
16343 }
16344 else
16353 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
16355 /* Now that we know visibility, instantiate the type so we have a
16356 declaration of the op() for later calls to lambda_function. */
16364 }
16367 /* We can get here for a constant initializer of non-dependent type.
16368 FIXME stop folding in cp_parser_initializer_clause. */
16369 {
16371 complain);
16373 }
16377 integral_constant_expression_p));
16383 {
16388 complain));
16389 }
16395 /* Handle Objective-C++ constructs, if appropriate. */
16396 {
16397 tree subst
16402 }
16404 }
16406 #undef RECUR
16407 #undef RETURN
16408 out:
16411 }
16413 /* Verify that the instantiated ARGS are valid. For type arguments,
16414 make sure that the type's linkage is ok. For non-type arguments,
16415 make sure they are constants if they are integral or enumerations.
16416 Emit an error under control of COMPLAIN, and return TRUE on error. */
16418 static bool
16420 {
16424 {
16434 }
16436 {
16437 /* [basic.link]: A name with no linkage (notably, the name
16438 of a class or enumeration declared in a local scope)
16439 shall not be used to declare an entity with linkage.
16440 This implies that names with no linkage cannot be used as
16441 template arguments
16443 DR 757 relaxes this restriction for C++0x. */
16448 {
16449 /* DR 488 makes use of a type with no linkage cause
16450 type deduction to fail. */
16452 {
16455 else
16458 }
16460 }
16461 /* In order to avoid all sorts of complications, we do not
16462 allow variably-modified types as template arguments. */
16464 {
16468 }
16469 }
16470 /* Class template and alias template arguments should be OK. */
16472 ;
16473 /* A non-type argument of integral or enumerated type must be a
16474 constant. */
16479 {
16483 }
16485 }
16487 static bool
16489 {
16494 {
16497 }
16501 }
16503 /* We're out of SFINAE context now, so generate diagnostics for the access
16504 errors we saw earlier when instantiating D from TMPL and ARGS. */
16506 static void
16508 {
16520 }
16522 /* Instantiate the indicated variable, function, or alias template TMPL with
16523 the template arguments in TARG_PTR. */
16525 static tree
16527 {
16529 tree fndecl;
16530 tree gen_tmpl;
16531 tree spec;
16539 /* If this function is a clone, handle it specially. */
16541 {
16542 tree spec;
16543 tree clone;
16545 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
16546 DECL_CLONED_FUNCTION. */
16552 /* Look for the clone. */
16556 /* We should always have found the clone by now. */
16559 }
16564 /* Check to see if we already have this specialization. */
16567 /* The TMPL is a partial instantiation. To get a full set of
16568 arguments we must add the arguments used to perform the
16569 partial instantiation. */
16571 targ_ptr);
16573 /* It would be nice to avoid hashing here and then again in tsubst_decl,
16574 but it doesn't seem to be on the hot path. */
16583 {
16585 {
16589 }
16591 }
16594 complain))
16597 /* We are building a FUNCTION_DECL, during which the access of its
16598 parameters and return types have to be checked. However this
16599 FUNCTION_DECL which is the desired context for access checking
16600 is not built yet. We solve this chicken-and-egg problem by
16601 deferring all checks until we have the FUNCTION_DECL. */
16604 /* Instantiation of the function happens in the context of the function
16605 template, not the context of the overload resolution we're doing. */
16607 /* If there are dependent arguments, e.g. because we're doing partial
16608 ordering, make sure processing_template_decl stays set. */
16612 {
16616 }
16621 {
16622 /* We need to determine if we're using a partial or explicit
16623 specialization now, because the type of the variable could be
16624 different. */
16630 {
16634 }
16635 }
16637 /* Substitute template parameters to obtain the specialization. */
16644 {
16647 }
16649 /* The DECL_TI_TEMPLATE should always be the immediate parent
16650 template, not the most general template. */
16654 /* Now we know the specialization, compute access previously
16655 deferred. */
16662 /* If we've just instantiated the main entry point for a function,
16663 instantiate all the alternate entry points as well. We do this
16664 by cloning the instantiation of the main entry point, not by
16665 instantiating the template clones. */
16670 {
16672 {
16673 /* Remember to reinstantiate when we're out of SFINAE so the user
16674 can see the errors. */
16676 }
16678 }
16680 }
16682 /* Wrapper for instantiate_template_1. */
16684 tree
16686 {
16687 tree ret;
16692 }
16694 /* Instantiate the alias template TMPL with ARGS. Also push a template
16695 instantiation level, which instantiate_template doesn't do because
16696 functions and variables have sufficient context established by the
16697 callers. */
16699 static tree
16701 {
16708 {
16711 }
16713 args =
16721 /* We can't free this if a pending_template entry or last_error_tinst_level
16722 is pointing at it. */
16728 }
16730 /* PARM is a template parameter pack for FN. Returns true iff
16731 PARM is used in a deducible way in the argument list of FN. */
16733 static bool
16735 {
16738 {
16740 tree packs;
16746 {
16747 /* The template parameter pack is used in a function parameter
16748 pack. If this is the end of the parameter list, the
16749 template parameter pack is deducible. */
16752 else
16753 /* Otherwise, not. Well, it could be deduced from
16754 a non-pack parameter, but doing so would end up with
16755 a deduction mismatch, so don't bother. */
16757 }
16758 }
16759 /* The template parameter pack isn't used in any function parameter
16760 packs, but it might be used deeper, e.g. tuple<Args...>. */
16762 }
16764 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
16765 NARGS elements of the arguments that are being used when calling
16766 it. TARGS is a vector into which the deduced template arguments
16767 are placed.
16769 Returns either a FUNCTION_DECL for the matching specialization of FN or
16770 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
16771 true, diagnostics will be printed to explain why it failed.
16773 If FN is a conversion operator, or we are trying to produce a specific
16774 specialization, RETURN_TYPE is the return type desired.
16776 The EXPLICIT_TARGS are explicit template arguments provided via a
16777 template-id.
16779 The parameter STRICT is one of:
16781 DEDUCE_CALL:
16782 We are deducing arguments for a function call, as in
16783 [temp.deduct.call].
16785 DEDUCE_CONV:
16786 We are deducing arguments for a conversion function, as in
16787 [temp.deduct.conv].
16789 DEDUCE_EXACT:
16790 We are deducing arguments when doing an explicit instantiation
16791 as in [temp.explicit], when determining an explicit specialization
16792 as in [temp.expl.spec], or when taking the address of a function
16793 template, as in [temp.deduct.funcaddr]. */
16795 tree
16797 tree explicit_targs,
16798 tree targs,
16801 tree return_type,
16802 unification_kind_t strict,
16806 {
16807 tree parms;
16808 tree fntype;
16816 tree tinst;
16822 /* In C++0x, it's possible to have a function template whose type depends
16823 on itself recursively. This is most obvious with decltype, but can also
16824 occur with enumeration scope (c++/48969). So we need to catch infinite
16825 recursion and reject the substitution at deduction time; this function
16826 will return error_mark_node for any repeated substitution.
16828 This also catches excessive recursion such as when f<N> depends on
16829 f<N-1> across all integers, and returns error_mark_node for all the
16830 substitutions back up to the initial one.
16832 This is, of course, not reentrant. */
16842 {
16843 /* [temp.deduct]
16845 The specified template arguments must match the template
16846 parameters in kind (i.e., type, nontype, template), and there
16847 must not be more arguments than there are parameters;
16848 otherwise type deduction fails.
16850 Nontype arguments must match the types of the corresponding
16851 nontype template parameters, or must be convertible to the
16852 types of the corresponding nontype parameters as specified in
16853 _temp.arg.nontype_, otherwise type deduction fails.
16855 All references in the function type of the function template
16856 to the corresponding template parameters are replaced by the
16857 specified template argument values. If a substitution in a
16858 template parameter or in the function type of the function
16859 template results in an invalid type, type deduction fails. */
16864 /* Adjust any explicit template arguments before entering the
16865 substitution context. */
16866 explicit_targs
16868 complain,
16874 /* Substitute the explicit args into the function type. This is
16875 necessary so that, for instance, explicitly declared function
16876 arguments can match null pointed constants. If we were given
16877 an incomplete set of explicit args, we must not do semantic
16878 processing during substitution as we could create partial
16879 instantiations. */
16881 {
16886 /* Dig out the actual parm. */
16889 {
16892 }
16894 {
16897 }
16900 /* No explicit argument for this template parameter. */
16904 {
16905 /* Mark the argument pack as "incomplete". We could
16906 still deduce more arguments during unification.
16907 We remove this mark in type_unification_real. */
16909 {
16913 }
16915 /* We have some incomplete argument packs. */
16917 }
16918 }
16922 {
16925 }
16928 /* Ignore any access checks; we'll see them again in
16929 instantiate_template and they might have the wrong
16930 access path at this point. */
16942 /* Place the explicitly specified arguments in TARGS. */
16945 }
16947 /* Never do unification on the 'this' parameter. */
16951 {
16960 }
16962 /* We allow incomplete unification without an error message here
16963 because the standard doesn't seem to explicitly prohibit it. Our
16964 callers must be ready to deal with unification failures in any
16965 event. */
16968 /* If we aren't explaining yet, push tinst context so we can see where
16969 any errors (e.g. from class instantiations triggered by instantiation
16970 of default template arguments) come from. If we are explaining, this
16971 context is redundant. */
16973 {
16976 }
16978 /* type_unification_real will pass back any access checks from default
16979 template argument substitution. */
16991 /* Now that we have bindings for all of the template arguments,
16992 ensure that the arguments deduced for the template template
16993 parameters have compatible template parameter lists. We cannot
16994 check this property before we have deduced all template
16995 arguments, because the template parameter types of a template
16996 template parameter might depend on prior template parameters
16997 deduced after the template template parameter. The following
16998 ill-formed example illustrates this issue:
17000 template<typename T, template<T> class C> void f(C<5>, T);
17002 template<int N> struct X {};
17004 void g() {
17005 f(X<5>(), 5l); // error: template argument deduction fails
17006 }
17008 The template parameter list of 'C' depends on the template type
17009 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
17010 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
17011 time that we deduce 'C'. */
17014 {
17017 }
17019 /* All is well so far. Now, check:
17021 [temp.deduct]
17023 When all template arguments have been deduced, all uses of
17024 template parameters in nondeduced contexts are replaced with
17025 the corresponding deduced argument values. If the
17026 substitution results in an invalid type, as described above,
17027 type deduction fails. */
17030 {
17033 }
17035 /* Also collect access checks from the instantiation. */
17048 /* Now perform any access checks encountered during substitution. */
17055 /* If we're looking for an exact match, check that what we got
17056 is indeed an exact match. It might not be if some template
17057 parameters are used in non-deduced contexts. But don't check
17058 for an exact match if we have dependent template arguments;
17059 in that case we're doing partial ordering, and we already know
17060 that we have two candidates that will provide the actual type. */
17062 {
17066 tree sarg
17072 {
17076 }
17077 }
17081 fail:
17084 {
17086 /* Reset once we're all the way out. */
17088 }
17090 /* We can't free this if a pending_template entry or last_error_tinst_level
17091 is pointing at it. */
17097 }
17099 /* Adjust types before performing type deduction, as described in
17100 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
17101 sections are symmetric. PARM is the type of a function parameter
17102 or the return type of the conversion function. ARG is the type of
17103 the argument passed to the call, or the type of the value
17104 initialized with the result of the conversion function.
17105 ARG_EXPR is the original argument expression, which may be null. */
17107 static int
17111 tree arg_expr)
17112 {
17116 {
17121 /* Swap PARM and ARG throughout the remainder of this
17122 function; the handling is precisely symmetric since PARM
17123 will initialize ARG rather than vice versa. */
17128 /* Core issue #873: Do the DR606 thing (see below) for these cases,
17129 too, but here handle it by stripping the reference from PARM
17130 rather than by adding it to ARG. */
17138 /* Nothing else to do in this case. */
17143 }
17146 {
17147 /* [temp.deduct.call]
17149 If P is not a reference type:
17151 --If A is an array type, the pointer type produced by the
17152 array-to-pointer standard conversion (_conv.array_) is
17153 used in place of A for type deduction; otherwise,
17155 --If A is a function type, the pointer type produced by
17156 the function-to-pointer standard conversion
17157 (_conv.func_) is used in place of A for type deduction;
17158 otherwise,
17160 --If A is a cv-qualified type, the top level
17161 cv-qualifiers of A's type are ignored for type
17162 deduction. */
17167 else
17169 }
17171 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
17172 of the form T&&, where T is a template parameter, and the argument
17173 is an lvalue, T is deduced as A& */
17179 /* try_one_overload doesn't provide an arg_expr, but
17180 functions are always lvalues. */
17184 /* [temp.deduct.call]
17186 If P is a cv-qualified type, the top level cv-qualifiers
17187 of P's type are ignored for type deduction. If P is a
17188 reference type, the type referred to by P is used for
17189 type deduction. */
17192 {
17195 }
17197 /* DR 322. For conversion deduction, remove a reference type on parm
17198 too (which has been swapped into ARG). */
17203 }
17205 /* Subroutine of unify_one_argument. PARM is a function parameter of a
17206 template which does contain any deducible template parameters; check if
17207 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
17208 unify_one_argument. */
17210 static int
17213 {
17214 tree type;
17218 else
17225 {
17229 }
17231 {
17236 }
17240 else
17242 }
17246 /* Returns true iff the expression EXPR is one from which a template
17247 argument can be deduced. In other words, if it's an undecorated
17248 use of a template non-type parameter. */
17250 static bool
17252 {
17254 }
17256 /* Returns true iff the array domain DOMAIN uses a template parameter in a
17257 deducible way; that is, if it has a max value of <PARM> - 1. */
17259 static bool
17261 {
17270 }
17272 /* Returns true iff the template arguments ARGS use a template parameter
17273 in a deducible way. */
17275 static bool
17277 {
17279 {
17284 else
17285 {
17292 else
17294 }
17297 }
17299 }
17301 /* Returns true iff TYPE contains any deducible references to template
17302 parameters, as per 14.8.2.5. */
17304 static bool
17306 {
17310 /* T
17311 cv-list T
17312 TT<T>
17313 TT<i>
17314 TT<> */
17319 /* T*
17320 T&
17321 T&& */
17325 /* T[integer-constant ]
17326 type [i] */
17331 /* T type ::*
17332 type T::*
17333 T T::*
17334 T (type ::*)()
17335 type (T::*)()
17336 type (type ::*)(T)
17337 type (T::*)(T)
17338 T (type ::*)(T)
17339 T (T::*)()
17340 T (T::*)(T) */
17343 || (uses_deducible_template_parms
17346 /* template-name <T> (where template-name refers to a class template)
17347 template-name <i> (where template-name refers to a class template) */
17354 /* type (T)
17355 T()
17356 T(T) */
17359 {
17368 }
17371 }
17373 /* Subroutine of type_unification_real and unify_pack_expansion to
17374 handle unification of a single P/A pair. Parameters are as
17375 for those functions. */
17377 static int
17381 {
17388 /* We can't deduce anything from this, but we might get all the
17389 template args from other function args. */
17392 /* Implicit conversions (Clause 4) will be performed on a function
17393 argument to convert it to the type of the corresponding function
17394 parameter if the parameter type contains no template-parameters that
17395 participate in template argument deduction. */
17398 /* For function parameters with no deducible template parameters,
17399 just return. We'll check non-dependent conversions later. */
17403 {
17405 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
17406 | UNIFY_ALLOW_MORE_CV_QUAL
17420 }
17422 /* We only do these transformations if this is the top-level
17423 parameter_type_list in a call or declaration matching; in other
17424 situations (nested function declarators, template argument lists) we
17425 won't be comparing a type to an expression, and we don't do any type
17426 adjustments. */
17428 {
17430 {
17433 {
17434 /* [temp.deduct.type] A template-argument can be
17435 deduced from a pointer to function or pointer
17436 to member function argument if the set of
17437 overloaded functions does not contain function
17438 templates and at most one of a set of
17439 overloaded functions provides a unique
17440 match. */
17447 }
17453 }
17455 arg_strict |=
17457 }
17458 else
17463 /* For deduction from an init-list we need the actual list. */
17467 }
17469 /* Most parms like fn_type_unification.
17471 If SUBR is 1, we're being called recursively (to unify the
17472 arguments of a function or method parameter of a function
17473 template).
17475 CHECKS is a pointer to a vector of access checks encountered while
17476 substituting default template arguments. */
17478 static int
17480 tree targs,
17481 tree xparms,
17485 unification_kind_t strict,
17489 {
17494 tree parms;
17503 /* Reset the number of non-defaulted template arguments contained
17504 in TARGS. */
17507 again:
17515 {
17520 /* For a function parameter pack that occurs at the end of the
17521 parameter-declaration-list, the type A of each remaining
17522 argument of the call is compared with the type P of the
17523 declarator-id of the function parameter pack. */
17529 /* For a function parameter pack that does not occur at the
17530 end of the parameter-declaration-list, the type of the
17531 parameter pack is a non-deduced context. */
17538 explain_p))
17540 }
17545 {
17546 /* Unify the remaining arguments with the pack expansion type. */
17547 tree argvec;
17550 /* Allocate a TREE_VEC and copy in all of the arguments */
17555 /* Copy the parameter into parmvec. */
17561 /* Advance to the end of the list of parameters. */
17563 }
17565 /* Fail if we've reached the end of the parm list, and more args
17566 are present, and the parm list isn't variadic. */
17569 /* Fail if parms are left and they don't have default values and
17570 they aren't all deduced as empty packs (c++/57397). This is
17571 consistent with sufficient_parms_p. */
17574 {
17578 do
17579 {
17582 count++;
17584 }
17588 type_pack_p);
17589 }
17592 {
17593 tsubst_flags_t complain = (explain_p
17594 ? tf_warning_or_error
17598 {
17602 /* Clear the "incomplete" flags on all argument packs now so that
17603 substituting them into later default arguments works. */
17605 {
17608 }
17614 /* If this is an undeduced nontype parameter that depends on
17615 a type parameter, try another pass; its type may have been
17616 deduced from a later argument than the one from which
17617 this parameter can be deduced. */
17621 {
17624 }
17626 /* Core issue #226 (C++0x) [temp.deduct]:
17628 If a template argument has not been deduced, its
17629 default template argument, if any, is used.
17631 When we are in C++98 mode, TREE_PURPOSE will either
17632 be NULL_TREE or ERROR_MARK_NODE, so we do not need
17633 to explicitly check cxx_dialect here. */
17635 /* OK, there is a default argument. Wait until after the
17636 conversion check to do substitution. */
17639 /* If the type parameter is a parameter pack, then it will
17640 be deduced to an empty parameter pack. */
17642 {
17643 tree arg;
17646 {
17650 }
17651 else
17658 }
17661 }
17663 /* DR 1391: All parameters have args, now check non-dependent parms for
17664 convertibility. */
17668 {
17674 /* For a function parameter pack that occurs at the end of the
17675 parameter-declaration-list, the type A of each remaining
17676 argument of the call is compared with the type P of the
17677 declarator-id of the function parameter pack. */
17683 /* For a function parameter pack that does not occur at the
17684 end of the parameter-declaration-list, the type of the
17685 parameter pack is a non-deduced context. */
17694 explain_p))
17696 }
17698 /* Now substitute into the default template arguments. */
17700 {
17726 else
17727 {
17729 /* The position of the first default template argument,
17730 is also the number of non-defaulted arguments in TARGS.
17731 Record that. */
17735 }
17736 }
17740 }
17741 #ifdef ENABLE_CHECKING
17744 #endif
17747 }
17749 /* Subroutine of type_unification_real. Args are like the variables
17750 at the call site. ARG is an overloaded function (or template-id);
17751 we try deducing template args from each of the overloads, and if
17752 only one succeeds, we go with that. Modifies TARGS and returns
17753 true on success. */
17755 static bool
17757 tree targs,
17758 tree parm,
17759 tree arg,
17760 unification_kind_t strict,
17763 {
17770 {
17773 }
17774 else
17778 /* Handle `&x' where `x' is some static or non-static member
17779 function name. */
17785 /* Strip baselink information. */
17790 {
17791 /* If we got some explicit template args, we need to plug them into
17792 the affected templates before we try to unify, in case the
17793 explicit args will completely resolve the templates in question. */
17800 {
17813 {
17818 {
17821 }
17822 }
17825 }
17826 /* If no templates (or more than one) are fully resolved by the
17827 explicit arguments, this template-id is a non-deduced context; it
17828 could still be OK if we deduce all template arguments for the
17829 enclosing call through other arguments. */
17832 }
17835 /* If ARG is, for example, "(0, &f)" then its type will be unknown
17836 -- but the deduction does not succeed because the expression is
17837 not just the function on its own. */
17839 else
17845 {
17848 }
17850 /* [temp.deduct.type] A template-argument can be deduced from a pointer
17851 to function or pointer to member function argument if the set of
17852 overloaded functions does not contain function templates and at most
17853 one of a set of overloaded functions provides a unique match.
17855 So if we found multiple possibilities, we return success but don't
17856 deduce anything. */
17859 {
17863 {
17868 /* Don't forget explicit template arguments in a pack. */
17872 }
17873 }
17878 }
17880 /* Core DR 115: In contexts where deduction is done and fails, or in
17881 contexts where deduction is not done, if a template argument list is
17882 specified and it, along with any default template arguments, identifies
17883 a single function template specialization, then the template-id is an
17884 lvalue for the function template specialization. */
17886 tree
17888 {
17901 {
17904 }
17906 {
17909 }
17911 {
17914 }
17917 {
17921 /* If we got some explicit template args, we need to plug them into
17922 the affected templates before we try to unify, in case the
17923 explicit args will completely resolve the templates in question. */
17931 {
17944 {
17947 {
17950 }
17952 {
17955 }
17956 }
17957 }
17959 {
17967 {
17968 tree base
17971 }
17975 }
17977 /* There were no good options and at least one bad one, so let the
17978 user know what the problem is. */
17980 }
17982 }
17984 /* Subroutine of resolve_overloaded_unification; does deduction for a single
17985 overload. Fills TARGS with any deduced arguments, or error_mark_node if
17986 different overloads deduce different arguments for a given parm.
17987 ADDR_P is true if the expression for which deduction is being
17988 performed was of the form "& fn" rather than simply "fn".
17990 Returns 1 on success. */
17992 static int
17994 tree orig_targs,
17995 tree targs,
17996 tree parm,
17997 tree arg,
17998 unification_kind_t strict,
18002 {
18004 tree tempargs;
18010 /* [temp.deduct.type] A template-argument can be deduced from a pointer
18011 to function or pointer to member function argument if the set of
18012 overloaded functions does not contain function templates and at most
18013 one of a set of overloaded functions provides a unique match.
18015 So if this is a template, just return success. */
18027 /* We don't copy orig_targs for this because if we have already deduced
18028 some template args from previous args, unify would complain when we
18029 try to deduce a template parameter for the same argument, even though
18030 there isn't really a conflict. */
18037 /* First make sure we didn't deduce anything that conflicts with
18038 explicitly specified args. */
18040 {
18047 /* Since we're unifying against ourselves, we will fill in
18048 template args used in the function parm list with our own
18049 template parms. Discard them. */
18053 }
18056 {
18061 }
18064 }
18066 /* PARM is a template class (perhaps with unbound template
18067 parameters). ARG is a fully instantiated type. If ARG can be
18068 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
18069 TARGS are as for unify. */
18071 static tree
18074 {
18075 tree copy_of_targs;
18082 /* We need to make a new template argument vector for the call to
18083 unify. If we used TARGS, we'd clutter it up with the result of
18084 the attempted unification, even if this class didn't work out.
18085 We also don't want to commit ourselves to all the unifications
18086 we've already done, since unification is supposed to be done on
18087 an argument-by-argument basis. In other words, consider the
18088 following pathological case:
18090 template <int I, int J, int K>
18091 struct S {};
18093 template <int I, int J>
18094 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
18096 template <int I, int J, int K>
18097 void f(S<I, J, K>, S<I, I, I>);
18099 void g() {
18100 S<0, 0, 0> s0;
18101 S<0, 1, 2> s2;
18103 f(s0, s2);
18104 }
18106 Now, by the time we consider the unification involving `s2', we
18107 already know that we must have `f<0, 0, 0>'. But, even though
18108 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
18109 because there are two ways to unify base classes of S<0, 1, 2>
18110 with S<I, I, I>. If we kept the already deduced knowledge, we
18111 would reject the possibility I=1. */
18114 /* If unification failed, we're done. */
18120 }
18122 /* Given a template type PARM and a class type ARG, find the unique
18123 base type in ARG that is an instance of PARM. We do not examine
18124 ARG itself; only its base-classes. If there is not exactly one
18125 appropriate base class, return NULL_TREE. PARM may be the type of
18126 a partial specialization, as well as a plain template type. Used
18127 by unify. */
18129 static enum template_base_result
18132 {
18134 tree binfo;
18140 {
18141 /* The type could not be completed. */
18144 }
18146 /* Walk in inheritance graph order. The search order is not
18147 important, and this avoids multiple walks of virtual bases. */
18149 {
18154 {
18155 /* If there is more than one satisfactory baseclass, then:
18157 [temp.deduct.call]
18159 If they yield more than one possible deduced A, the type
18160 deduction fails.
18162 applies. */
18164 {
18167 }
18170 }
18171 }
18175 }
18177 /* Returns the level of DECL, which declares a template parameter. */
18179 static int
18181 {
18183 {
18193 }
18195 }
18197 /* Decide whether ARG can be unified with PARM, considering only the
18198 cv-qualifiers of each type, given STRICT as documented for unify.
18199 Returns nonzero iff the unification is OK on that basis. */
18201 static int
18203 {
18209 {
18210 /* Although a CVR qualifier is ignored when being applied to a
18211 substituted template parameter ([8.3.2]/1 for example), that
18212 does not allow us to unify "const T" with "int&" because both
18213 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
18214 It is ok when we're allowing additional CV qualifiers
18215 at the outer level [14.8.2.1]/3,1st bullet. */
18225 }
18236 }
18238 /* Determines the LEVEL and INDEX for the template parameter PARM. */
18239 void
18241 {
18245 {
18248 }
18249 else
18250 {
18253 }
18254 }
18256 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
18257 do { \
18258 if (unify (TP, TA, P, A, S, EP)) \
18259 return 1; \
18260 } while (0);
18262 /* Unifies the remaining arguments in PACKED_ARGS with the pack
18263 expansion at the end of PACKED_PARMS. Returns 0 if the type
18264 deduction succeeds, 1 otherwise. STRICT is the same as in
18265 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
18266 call argument list. We'll need to adjust the arguments to make them
18267 types. SUBR tells us if this is from a recursive call to
18268 type_unification_real, or for comparing two template argument
18269 lists. */
18271 static int
18275 {
18276 tree parm
18286 /* Determine the parameter packs we will be deducing from the
18287 pattern, and record their current deductions. */
18290 {
18294 /* Determine the index and level of this parameter pack. */
18297 /* Keep track of the parameter packs and their corresponding
18298 argument packs. */
18301 }
18303 /* Loop through all of the arguments that have not yet been
18304 unified and unify each with the pattern. */
18306 {
18307 tree parm;
18311 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
18312 or the element of its argument pack at the current index if
18313 this argument was explicitly specified. */
18315 {
18324 {
18327 }
18329 }
18331 /* If we had explicit template arguments, substitute them into the
18332 pattern before deduction. */
18334 {
18335 /* Some arguments might still be unspecified or dependent. */
18343 NULL_TREE);
18348 }
18349 else
18352 /* Unify the pattern with the current argument. */
18354 explain_p))
18357 /* For each parameter pack, collect the deduced value. */
18359 {
18365 }
18366 }
18368 /* Verify that the results of unification with the parameter packs
18369 produce results consistent with what we've seen before, and make
18370 the deduced argument packs available. */
18372 {
18379 /* By default keep the original deduced argument pack.
18380 If necessary, more specific code is going to update the
18381 resulting deduced argument later down in this function. */
18385 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
18386 actually deduce anything. */
18394 {
18395 /* If we had fewer function args than explicit template args,
18396 just use the explicits. */
18401 }
18404 {
18405 tree result;
18406 /* Build the deduced *_ARGUMENT_PACK. */
18408 {
18413 }
18414 else
18419 /* Note the deduced argument packs for this parameter
18420 pack. */
18422 }
18426 {
18427 /* We only had the explicitly-provided arguments before, but
18428 now we have a complete set of arguments. */
18434 }
18435 else
18436 {
18442 /* Inconsistent unification of this parameter pack. */
18444 bad_old_arg,
18445 bad_new_arg);
18446 }
18447 }
18450 }
18452 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
18453 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
18454 parameters and return value are as for unify. */
18456 static int
18460 {
18461 tree parm_max;
18462 tree arg_max;
18466 /* Our representation of array types uses "N - 1" as the
18467 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
18468 not an integer constant. We cannot unify arbitrarily
18469 complex expressions, so we eliminate the MINUS_EXPRs
18470 here. */
18474 {
18477 }
18481 {
18482 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
18483 trying to unify the type of a variable with the type
18484 of a template parameter. For example:
18486 template <unsigned int N>
18487 void f (char (&) [N]);
18488 int g();
18489 void h(int i) {
18490 char a[g(i)];
18491 f(a);
18492 }
18494 Here, the type of the ARG will be "int [g(i)]", and
18495 may be a SAVE_EXPR, etc. */
18499 }
18501 /* If only one of the bounds used a MINUS_EXPR, compensate
18502 by adding one to the other bound. */
18505 integer_type_node,
18506 parm_max,
18507 integer_one_node);
18510 integer_type_node,
18511 arg_max,
18512 integer_one_node);
18516 }
18518 /* Deduce the value of template parameters. TPARMS is the (innermost)
18519 set of template parameters to a template. TARGS is the bindings
18520 for those template parameters, as determined thus far; TARGS may
18521 include template arguments for outer levels of template parameters
18522 as well. PARM is a parameter to a template function, or a
18523 subcomponent of that parameter; ARG is the corresponding argument.
18524 This function attempts to match PARM with ARG in a manner
18525 consistent with the existing assignments in TARGS. If more values
18526 are deduced, then TARGS is updated.
18528 Returns 0 if the type deduction succeeds, 1 otherwise. The
18529 parameter STRICT is a bitwise or of the following flags:
18531 UNIFY_ALLOW_NONE:
18532 Require an exact match between PARM and ARG.
18533 UNIFY_ALLOW_MORE_CV_QUAL:
18534 Allow the deduced ARG to be more cv-qualified (by qualification
18535 conversion) than ARG.
18536 UNIFY_ALLOW_LESS_CV_QUAL:
18537 Allow the deduced ARG to be less cv-qualified than ARG.
18538 UNIFY_ALLOW_DERIVED:
18539 Allow the deduced ARG to be a template base class of ARG,
18540 or a pointer to a template base class of the type pointed to by
18541 ARG.
18542 UNIFY_ALLOW_INTEGER:
18543 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
18544 case for more information.
18545 UNIFY_ALLOW_OUTER_LEVEL:
18546 This is the outermost level of a deduction. Used to determine validity
18547 of qualification conversions. A valid qualification conversion must
18548 have const qualified pointers leading up to the inner type which
18549 requires additional CV quals, except at the outer level, where const
18550 is not required [conv.qual]. It would be normal to set this flag in
18551 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
18552 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
18553 This is the outermost level of a deduction, and PARM can be more CV
18554 qualified at this point.
18555 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
18556 This is the outermost level of a deduction, and PARM can be less CV
18557 qualified at this point. */
18559 static int
18562 {
18564 tree targ;
18565 tree tparm;
18568 /* I don't think this will do the right thing with respect to types.
18569 But the only case I've seen it in so far has been array bounds, where
18570 signedness is the only information lost, and I think that will be
18571 okay. */
18579 /* We can't deduce anything from this, but we might get all the
18580 template args from other function args. */
18583 /* If PARM uses template parameters, then we can't bail out here,
18584 even if ARG == PARM, since we won't record unifications for the
18585 template parameters. We might need them if we're trying to
18586 figure out which of two things is more specialized. */
18590 /* Handle init lists early, so the rest of the function can assume
18591 we're dealing with a type. */
18593 {
18598 /* Replace T with std::initializer_list<T> for deduction. */
18605 /* We can only deduce from an initializer list argument if the
18606 parameter is std::initializer_list or an array; otherwise this
18607 is a non-deduced context. */
18612 else
18613 {
18615 /* Deduction is defined in terms of a single type, so just punt
18616 on the (bizarre) std::initializer_list<T...>. */
18619 }
18622 {
18629 {
18633 /* It should only be possible to get here for a call. */
18635 elt_strict |= maybe_adjust_types_for_deduction
18638 }
18641 explain_p);
18642 }
18646 {
18647 /* Also deduce from the length of the initializer list. */
18654 }
18656 /* If the std::initializer_list<T> deduction worked, replace the
18657 deduced A with std::initializer_list<A>. */
18659 {
18664 }
18666 }
18668 /* Immediately reject some pairs that won't unify because of
18669 cv-qualification mismatches. */
18672 /* It is the elements of the array which hold the cv quals of an array
18673 type, and the elements might be template type parms. We'll check
18674 when we recurse. */
18676 /* We check the cv-qualifiers when unifying with template type
18677 parameters below. We want to allow ARG `const T' to unify with
18678 PARM `T' for example, when computing which of two templates
18679 is more specialized, for example. */
18693 {
18697 /* In a type which contains a nested-name-specifier, template
18698 argument values cannot be deduced for template parameters used
18699 within the nested-name-specifier. */
18711 /* The PARM is not one we're trying to unify. Just check
18712 to see if it matches ARG. */
18713 {
18718 else
18720 }
18727 /* Check for mixed types and values. */
18735 {
18736 /* ARG must be constructed from a template class or a template
18737 template parameter. */
18741 {
18743 /* An alias template name is never deduced. */
18748 tree parm_parms
18749 = DECL_INNERMOST_TEMPLATE_PARMS
18754 /* The resolution to DR150 makes clear that default
18755 arguments for an N-argument may not be used to bind T
18756 to a template template parameter with fewer than N
18757 parameters. It is not safe to permit the binding of
18758 default arguments as an extension, as that may change
18759 the meaning of a conforming program. Consider:
18761 struct Dense { static const unsigned int dim = 1; };
18763 template <template <typename> class View,
18764 typename Block>
18765 void operator+(float, View<Block> const&);
18767 template <typename Block,
18768 unsigned int Dim = Block::dim>
18769 struct Lvalue_proxy { operator float() const; };
18771 void
18772 test_1d (void) {
18773 Lvalue_proxy<Dense> p;
18774 float b;
18775 b + p;
18776 }
18778 Here, if Lvalue_proxy is permitted to bind to View, then
18779 the global operator+ will be used; if they are not, the
18780 Lvalue_proxy will be converted to float. */
18782 full_argvec,
18784 (explain_p
18785 ? tf_warning_or_error
18792 /* Deduce arguments T, i from TT<T> or TT<i>.
18793 We check each element of PARMVEC and ARGVEC individually
18794 rather than the whole TREE_VEC since they can have
18795 different number of elements. */
18802 /* Check if the parameters end in a pack, making them
18803 variadic. */
18809 /* If the template argument list of P contains a pack
18810 expansion that is not the last template argument, the
18811 entire template argument list is a non-deduced
18812 context. */
18821 {
18826 }
18831 DEDUCE_EXACT,
18834 }
18837 /* Fall through to deduce template name. */
18838 }
18842 {
18843 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
18845 /* Simple cases: Value already set, does match or doesn't. */
18850 }
18851 else
18852 {
18853 /* If PARM is `const T' and ARG is only `int', we don't have
18854 a match unless we are allowing additional qualification.
18855 If ARG is `const int' and PARM is just `T' that's OK;
18856 that binds `const int' to `T'. */
18861 /* Consider the case where ARG is `const volatile int' and
18862 PARM is `const T'. Then, T should be `volatile int'. */
18863 arg = cp_build_qualified_type_real
18868 /* Simple cases: Value already set, does match or doesn't. */
18874 /* Make sure that ARG is not a variable-sized array. (Note
18875 that were talking about variable-sized arrays (like
18876 `int[n]'), rather than arrays of unknown size (like
18877 `int[]').) We'll get very confused by such a type since
18878 the bound of the array is not constant, and therefore
18879 not mangleable. Besides, such types are not allowed in
18880 ISO C++, so we can do as we please here. We do allow
18881 them for 'auto' deduction, since that isn't ABI-exposed. */
18885 /* Strip typedefs as in convert_template_argument. */
18887 }
18889 /* If ARG is a parameter pack or an expansion, we cannot unify
18890 against it unless PARM is also a parameter pack. */
18895 /* If the argument deduction results is a METHOD_TYPE,
18896 then there is a problem.
18897 METHOD_TYPE doesn't map to any real C++ type the result of
18898 the deduction can not be of that type. */
18912 {
18913 /* The PARM is not one we're trying to unify. Just check
18914 to see if it matches ARG. */
18920 }
18926 {
18931 }
18933 /* [temp.deduct.type] If, in the declaration of a function template
18934 with a non-type template-parameter, the non-type
18935 template-parameter is used in an expression in the function
18936 parameter-list and, if the corresponding template-argument is
18937 deduced, the template-argument type shall match the type of the
18938 template-parameter exactly, except that a template-argument
18939 deduced from an array bound may be of any integral type.
18940 The non-type parameter might use already deduced type parameters. */
18943 /* Template-parameter dependent expression. Just accept it for now.
18944 It will later be processed in convert_template_argument. */
18945 ;
18950 /* Convert the ARG to the type of PARM; the deduced non-type
18951 template argument must exactly match the types of the
18952 corresponding parameter. */
18955 /* We haven't deduced the type of this parameter yet. Try again
18956 later. */
18958 else
18961 /* If ARG is a parameter pack or an expansion, we cannot unify
18962 against it unless PARM is also a parameter pack. */
18967 {
18970 }
18975 {
18976 /* A pointer-to-member constant can be unified only with
18977 another constant. */
18981 /* Just unify the class member. It would be useless (and possibly
18982 wrong, depending on the strict flags) to unify also
18983 PTRMEM_CST_CLASS, because we want to be sure that both parm and
18984 arg refer to the same variable, even if through different
18985 classes. For instance:
18987 struct A { int x; };
18988 struct B : A { };
18990 Unification of &A::x and &B::x must succeed. */
18993 }
18996 {
19000 /* [temp.deduct.call]
19002 A can be another pointer or pointer to member type that can
19003 be converted to the deduced A via a qualification
19004 conversion (_conv.qual_).
19006 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
19007 This will allow for additional cv-qualification of the
19008 pointed-to types if appropriate. */
19011 /* The derived-to-base conversion only persists through one
19012 level of pointers. */
19017 }
19049 /* We have already checked cv-qualification at the top of the
19050 function. */
19054 /* As far as unification is concerned, this wins. Later checks
19055 will invalidate it if necessary. */
19058 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
19059 /* Type INTEGER_CST can come from ordinary constant template args. */
19071 {
19081 /* Check for pack expansions in the parameters. */
19083 {
19085 {
19087 /* We can unify against something with a trailing
19088 parameter pack. */
19090 else
19091 /* [temp.deduct.type]/9: If the template argument list of
19092 P contains a pack expansion that is not the last
19093 template argument, the entire template argument list
19094 is a non-deduced context. */
19096 }
19097 }
19099 /* If we don't have enough arguments to satisfy the parameters
19100 (not counting the pack expression at the end), or we have
19101 too many arguments for a parameter list that doesn't end in
19102 a pack expression, we can't unify. */
19108 /* Unify all of the parameters that precede the (optional)
19109 pack expression. */
19111 {
19116 }
19119 DEDUCE_EXACT,
19122 }
19130 {
19138 }
19143 {
19147 {
19148 /* First, we try to unify the PARM and ARG directly. */
19153 {
19154 /* Fallback to the special case allowed in
19155 [temp.deduct.call]:
19157 If P is a class, and P has the form
19158 template-id, then A can be a derived class of
19159 the deduced A. Likewise, if P is a pointer to
19160 a class of the form template-id, A can be a
19161 pointer to a derived class pointed to by the
19162 deduced A. */
19169 }
19170 }
19174 /* Perhaps PARM is something like S<U> and ARG is S<int>.
19175 Then, we should unify `int' and `U'. */
19177 else
19178 /* There's no chance of unification succeeding. */
19183 }
19190 {
19193 tree a;
19199 /* CV qualifications for methods can never be deduced, they must
19200 match exactly. We need to check them explicitly here,
19201 because type_unification_real treats them as any other
19202 cv-qualified parameter. */
19204 && (!check_cv_quals_for_unify
19224 }
19227 /* Unify a pointer to member with a pointer to member function, which
19228 deduces the type of the member as a function type. */
19230 {
19231 /* Check top-level cv qualifiers */
19239 /* Determine the type of the function we are unifying against. */
19243 }
19262 /* Matched cases are handled by the ARG == PARM test above. */
19266 /* A non-type template parameter that is a variable should be a
19267 an integral constant, in which case, it whould have been
19268 folded into its (constant) value. So we should not be getting
19269 a variable here. */
19280 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
19281 or UNDERLYING_TYPE nodes. */
19285 /* Unification fails if we hit an error node. */
19290 {
19295 }
19296 /* FALLTHRU */
19299 /* An unresolved overload is a nondeduced context. */
19304 /* We must be looking at an expression. This can happen with
19305 something like:
19307 template <int I>
19308 void foo(S<I>, S<I + 2>);
19310 This is a "nondeduced context":
19312 [deduct.type]
19314 The nondeduced contexts are:
19316 --A type that is a template-id in which one or more of
19317 the template-arguments is an expression that references
19318 a template-parameter.
19320 In these cases, we assume deduction succeeded, but don't
19321 actually infer any unifications. */
19326 else
19328 }
19329 }
19330 #undef RECUR_AND_CHECK_FAILURE
19331 \f
19332 /* Note that DECL can be defined in this translation unit, if
19333 required. */
19335 static void
19337 {
19338 tree clone;
19342 }
19344 /* Called if RESULT is explicitly instantiated, or is a member of an
19345 explicitly instantiated class. */
19347 void
19349 {
19352 /* If this entity has already been written out, it's too late to
19353 make any modifications. */
19357 /* For anonymous namespace we don't need to do anything. */
19359 {
19362 }
19365 /* The TREE_PUBLIC flag for function declarations will have been
19366 set correctly by tsubst. */
19369 /* This might have been set by an earlier implicit instantiation. */
19374 else
19375 {
19378 /* Always make artificials weak. */
19381 /* For WIN32 we also want to put explicit instantiations in
19382 linkonce sections. */
19385 }
19387 /* If EXTERN_P, then this function will not be emitted -- unless
19388 followed by an explicit instantiation, at which point its linkage
19389 will be adjusted. If !EXTERN_P, then this function will be
19390 emitted here. In neither circumstance do we want
19391 import_export_decl to adjust the linkage. */
19393 }
19395 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
19396 important template arguments. If any are missing, we check whether
19397 they're important by using error_mark_node for substituting into any
19398 args that were used for partial ordering (the ones between ARGS and END)
19399 and seeing if it bubbles up. */
19401 static bool
19403 {
19408 {
19411 }
19413 {
19417 }
19419 }
19421 /* Given two function templates PAT1 and PAT2, return:
19423 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
19424 -1 if PAT2 is more specialized than PAT1.
19425 0 if neither is more specialized.
19427 LEN indicates the number of parameters we should consider
19428 (defaulted parameters should not be considered).
19430 The 1998 std underspecified function template partial ordering, and
19431 DR214 addresses the issue. We take pairs of arguments, one from
19432 each of the templates, and deduce them against each other. One of
19433 the templates will be more specialized if all the *other*
19434 template's arguments deduce against its arguments and at least one
19435 of its arguments *does* *not* deduce against the other template's
19436 corresponding argument. Deduction is done as for class templates.
19437 The arguments used in deduction have reference and top level cv
19438 qualifiers removed. Iff both arguments were originally reference
19439 types *and* deduction succeeds in both directions, an lvalue reference
19440 wins against an rvalue reference and otherwise the template
19441 with the more cv-qualified argument wins for that pairing (if
19442 neither is more cv-qualified, they both are equal). Unlike regular
19443 deduction, after all the arguments have been deduced in this way,
19444 we do *not* verify the deduced template argument values can be
19445 substituted into non-deduced contexts.
19447 The logic can be a bit confusing here, because we look at deduce1 and
19448 targs1 to see if pat2 is at least as specialized, and vice versa; if we
19449 can find template arguments for pat1 to make arg1 look like arg2, that
19450 means that arg2 is at least as specialized as arg1. */
19452 int
19454 {
19467 /* Remove the this parameter from non-static member functions. If
19468 one is a non-static member function and the other is not a static
19469 member function, remove the first parameter from that function
19470 also. This situation occurs for operator functions where we
19471 locate both a member function (with this pointer) and non-member
19472 operator (with explicit first operand). */
19474 {
19479 }
19481 {
19484 {
19485 len--;
19487 }
19488 }
19490 /* If only one is a conversion operator, they are unordered. */
19494 /* Consider the return type for a conversion function */
19496 {
19499 len++;
19500 }
19502 processing_template_decl++;
19508 /* Stop when an ellipsis is seen. */
19510 {
19521 {
19522 /* When both arguments are pack expansions, we need only
19523 unify the patterns themselves. */
19527 /* This is the last comparison we need to do. */
19529 }
19532 {
19536 }
19539 {
19543 }
19549 {
19555 /* Setup the parameter vector, which contains only ARG1. */
19558 /* Setup the argument vector, which contains the remaining
19559 arguments. */
19568 /* We cannot deduce in the other direction, because ARG1 is
19569 a pack expansion but ARG2 is not. */
19571 }
19573 {
19579 /* Setup the parameter vector, which contains only ARG1. */
19582 /* Setup the argument vector, which contains the remaining
19583 arguments. */
19592 /* We cannot deduce in the other direction, because ARG2 is
19593 a pack expansion but ARG1 is not.*/
19595 }
19597 else
19598 {
19599 /* The normal case, where neither argument is a pack
19600 expansion. */
19607 }
19609 /* If we couldn't deduce arguments for tparms1 to make arg1 match
19610 arg2, then arg2 is not as specialized as arg1. */
19616 /* "If, for a given type, deduction succeeds in both directions
19617 (i.e., the types are identical after the transformations above)
19618 and both P and A were reference types (before being replaced with
19619 the type referred to above):
19620 - if the type from the argument template was an lvalue reference and
19621 the type from the parameter template was not, the argument type is
19622 considered to be more specialized than the other; otherwise,
19623 - if the type from the argument template is more cv-qualified
19624 than the type from the parameter template (as described above),
19625 the argument type is considered to be more specialized than the other;
19626 otherwise,
19627 - neither type is more specialized than the other." */
19630 {
19632 {
19635 else
19637 }
19639 {
19644 }
19645 }
19648 /* We've failed to deduce something in either direction.
19649 These must be unordered. */
19654 /* We have already processed all of the arguments in our
19655 handing of the pack expansion type. */
19660 }
19662 /* "In most cases, all template parameters must have values in order for
19663 deduction to succeed, but for partial ordering purposes a template
19664 parameter may remain without a value provided it is not used in the
19665 types being used for partial ordering."
19667 Thus, if we are missing any of the targs1 we need to substitute into
19668 origs1, then pat2 is not as specialized as pat1. This can happen when
19669 there is a nondeduced context. */
19675 processing_template_decl--;
19677 /* If both deductions succeed, the partial ordering selects the more
19678 constrained template. */
19680 {
19685 }
19687 /* All things being equal, if the next argument is a pack expansion
19688 for one function but not for the other, prefer the
19689 non-variadic function. FIXME this is bogus; see c++/41958. */
19693 {
19696 }
19702 else
19704 }
19706 /* Determine which of two partial specializations of TMPL is more
19707 specialized.
19709 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
19710 to the first partial specialization. The TREE_PURPOSE is the
19711 innermost set of template parameters for the partial
19712 specialization. PAT2 is similar, but for the second template.
19714 Return 1 if the first partial specialization is more specialized;
19715 -1 if the second is more specialized; 0 if neither is more
19716 specialized.
19718 See [temp.class.order] for information about determining which of
19719 two templates is more specialized. */
19721 static int
19723 {
19724 tree targs;
19735 /* Just like what happens for functions, if we are ordering between
19736 different template specializations, we may encounter dependent
19737 types in the arguments, and we need our dependency check functions
19738 to behave correctly. */
19742 {
19745 }
19749 {
19752 }
19755 /* If both deductions succeed, the partial ordering selects the more
19756 constrained template. */
19760 /* In the case of a tie where at least one of the templates
19761 has a parameter pack at the end, the template with the most
19762 non-packed parameters wins. */
19764 && any_deductions
19767 {
19773 /* We don't count the pack expansion at the end. */
19783 }
19786 }
19788 /* Return the template arguments that will produce the function signature
19789 DECL from the function template FN, with the explicit template
19790 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
19791 also match. Return NULL_TREE if no satisfactory arguments could be
19792 found. */
19794 static tree
19796 {
19800 tree decl_arg_types;
19803 tree arg;
19807 /* Never do unification on the 'this' parameter. */
19828 }
19830 /* Return the innermost template arguments that, when applied to a partial
19831 specialization of TMPL whose innermost template parameters are
19832 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
19833 ARGS.
19835 For example, suppose we have:
19837 template <class T, class U> struct S {};
19838 template <class T> struct S<T*, int> {};
19840 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
19841 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
19842 int}. The resulting vector will be {double}, indicating that `T'
19843 is bound to `double'. */
19845 static tree
19847 {
19849 tree deduced_args;
19850 tree innermost_deduced_args;
19854 {
19858 innermost_deduced_args);
19859 }
19860 else
19873 /* Verify that nondeduced template arguments agree with the type
19874 obtained from argument deduction.
19876 For example:
19878 struct A { typedef int X; };
19879 template <class T, class U> struct C {};
19880 template <class T> struct C<T, typename T::X> {};
19882 Then with the instantiation `C<A, int>', we can deduce that
19883 `T' is `A' but unify () does not check whether `typename T::X'
19884 is `int'. */
19890 /* We only need to check the innermost arguments; the other
19891 arguments will always agree. */
19896 /* Now that we have bindings for all of the template arguments,
19897 ensure that the arguments deduced for the template template
19898 parameters have compatible template parameter lists. See the use
19899 of template_template_parm_bindings_ok_p in fn_type_unification
19900 for more information. */
19905 }
19907 // Compare two function templates T1 and T2 by deducing bindings
19908 // from one against the other. If both deductions succeed, compare
19909 // constraints to see which is more constrained.
19910 static int
19912 {
19917 {
19920 }
19923 {
19926 }
19928 // If both deductions succeed, then one may be more constrained.
19933 }
19935 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
19936 Return the TREE_LIST node with the most specialized template, if
19937 any. If there is no most specialized template, the error_mark_node
19938 is returned.
19940 Note that this function does not look at, or modify, the
19941 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
19942 returned is one of the elements of INSTANTIATIONS, callers may
19943 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
19944 and retrieve it from the value returned. */
19946 tree
19948 {
19955 {
19960 {
19961 /* Equally specialized, move to next function. If there
19962 is no next function, nothing's most specialized. */
19967 }
19968 }
19971 /* Now verify that champ is better than everything earlier in the
19972 instantiation list. */
19975 {
19978 }
19979 }
19981 processing_template_decl--;
19987 }
19989 /* If DECL is a specialization of some template, return the most
19990 general such template. Otherwise, returns NULL_TREE.
19992 For example, given:
19994 template <class T> struct S { template <class U> void f(U); };
19996 if TMPL is `template <class U> void S<int>::f(U)' this will return
19997 the full template. This function will not trace past partial
19998 specializations, however. For example, given in addition:
20000 template <class T> struct S<T*> { template <class U> void f(U); };
20002 if TMPL is `template <class U> void S<int*>::f(U)' this will return
20003 `template <class T> template <class U> S<T*>::f(U)'. */
20005 tree
20007 {
20009 {
20012 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
20013 template friend, or a FIELD_DECL for a capture pack. */
20016 }
20018 /* Look for more and more general templates. */
20020 {
20021 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
20022 (See cp-tree.h for details.) */
20031 /* Stop if we run into an explicitly specialized class template. */
20038 }
20041 }
20043 /* Return the most specialized of the template partial specializations
20044 which can produce TARGET, a specialization of some class or variable
20045 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
20046 a TEMPLATE_DECL node corresponding to the partial specialization, while
20047 the TREE_PURPOSE is the set of template arguments that must be
20048 substituted into the template pattern in order to generate TARGET.
20050 If the choice of partial specialization is ambiguous, a diagnostic
20051 is issued, and the error_mark_node is returned. If there are no
20052 partial specializations matching TARGET, then NULL_TREE is
20053 returned, indicating that the primary template should be used. */
20055 static tree
20057 {
20059 tree t;
20060 tree champ;
20067 {
20071 }
20073 {
20076 }
20078 {
20082 }
20083 else
20088 /* For determining which partial specialization to use, only the
20089 innermost args are interesting. */
20091 {
20094 }
20097 {
20098 tree partial_spec_args;
20099 tree spec_args;
20107 {
20108 /* Discard the outer levels of args, and then substitute in the
20109 template args from the enclosing class. */
20111 partial_spec_args = tsubst_template_args
20114 /* And the same for the partial specialization TEMPLATE_DECL. */
20116 }
20118 partial_spec_args =
20120 partial_spec_args,
20134 partial_spec_args,
20135 args);
20137 {
20141 /* Keep the candidate only if the constraints are satisfied,
20142 or if we're not compiling with concepts. */
20145 {
20148 }
20149 }
20150 }
20160 {
20163 ;
20164 else
20165 {
20167 {
20170 {
20173 }
20174 }
20176 }
20177 }
20181 {
20184 {
20187 }
20188 }
20191 {
20198 else
20202 {
20207 }
20210 }
20213 }
20215 /* Explicitly instantiate DECL. */
20217 void
20219 {
20224 /* An error occurred, for which grokdeclarator has already issued
20225 an appropriate message. */
20228 {
20231 }
20237 {
20238 /* There is an asymmetry here in the way VAR_DECLs and
20239 FUNCTION_DECLs are handled by grokdeclarator. In the case of
20240 the latter, the DECL we get back will be marked as a
20241 template instantiation, and the appropriate
20242 DECL_TEMPLATE_INFO will be set up. This does not happen for
20243 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
20244 should handle VAR_DECLs as it currently handles
20245 FUNCTION_DECLs. */
20247 {
20250 }
20253 {
20256 }
20258 {
20263 }
20264 }
20266 {
20269 }
20270 else
20273 /* Check for various error cases. Note that if the explicit
20274 instantiation is valid the RESULT will currently be marked as an
20275 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
20276 until we get here. */
20279 {
20280 /* DR 259 [temp.spec].
20282 Both an explicit instantiation and a declaration of an explicit
20283 specialization shall not appear in a program unless the explicit
20284 instantiation follows a declaration of the explicit specialization.
20286 For a given set of template parameters, if an explicit
20287 instantiation of a template appears after a declaration of an
20288 explicit specialization for that template, the explicit
20289 instantiation has no effect. */
20291 }
20293 {
20294 /* [temp.spec]
20296 No program shall explicitly instantiate any template more
20297 than once.
20299 We check DECL_NOT_REALLY_EXTERN so as not to complain when
20300 the first instantiation was `extern' and the second is not,
20301 and EXTERN_P for the opposite case. */
20304 /* If an "extern" explicit instantiation follows an ordinary
20305 explicit instantiation, the template is instantiated. */
20308 }
20310 {
20313 }
20315 {
20318 }
20321 ;
20323 {
20326 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
20329 }
20330 else
20338 }
20340 static void
20342 {
20348 {
20351 }
20352 }
20354 /* Called from do_type_instantiation through binding_table_foreach to
20355 do recursive instantiation for the type bound in ENTRY. */
20356 static void
20358 {
20364 }
20366 /* Called from do_type_instantiation to instantiate a member
20367 (a member function or a static member variable) of an
20368 explicitly instantiated class template. */
20369 static void
20371 {
20376 }
20378 /* Perform an explicit instantiation of template class T. STORAGE, if
20379 non-null, is the RID for extern, inline or static. COMPLAIN is
20380 nonzero if this is called from the parser, zero if called recursively,
20381 since the standard is unclear (as detailed below). */
20383 void
20385 {
20395 {
20396 tree tmpl =
20400 else
20403 }
20408 {
20411 t);
20413 }
20416 {
20418 {
20420 {
20423 "ISO C++ 1998 forbids the use of %<extern%> on "
20425 }
20426 else
20428 "ISO C++ forbids the use of %qE"
20430 }
20438 else
20439 {
20441 storage);
20443 }
20444 }
20447 {
20448 /* DR 259 [temp.spec].
20450 Both an explicit instantiation and a declaration of an explicit
20451 specialization shall not appear in a program unless the explicit
20452 instantiation follows a declaration of the explicit specialization.
20454 For a given set of template parameters, if an explicit
20455 instantiation of a template appears after a declaration of an
20456 explicit specialization for that template, the explicit
20457 instantiation has no effect. */
20459 }
20461 {
20462 /* [temp.spec]
20464 No program shall explicitly instantiate any template more
20465 than once.
20467 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
20468 instantiation was `extern'. If EXTERN_P then the second is.
20469 These cases are OK. */
20476 /* If we've already instantiated the template, just return now. */
20479 }
20487 {
20488 tree tmp;
20490 /* In contrast to implicit instantiation, where only the
20491 declarations, and not the definitions, of members are
20492 instantiated, we have here:
20494 [temp.explicit]
20496 The explicit instantiation of a class template specialization
20497 implies the instantiation of all of its members not
20498 previously explicitly specialized in the translation unit
20499 containing the explicit instantiation.
20501 Of course, we can't instantiate member template classes, since
20502 we don't have any arguments for them. Note that the standard
20503 is unclear on whether the instantiation of the members are
20504 *explicit* instantiations or not. However, the most natural
20505 interpretation is that it should be an explicit instantiation. */
20520 }
20521 }
20523 /* Given a function DECL, which is a specialization of TMPL, modify
20524 DECL to be a re-instantiation of TMPL with the same template
20525 arguments. TMPL should be the template into which tsubst'ing
20526 should occur for DECL, not the most general template.
20528 One reason for doing this is a scenario like this:
20530 template <class T>
20531 void f(const T&, int i);
20533 void g() { f(3, 7); }
20535 template <class T>
20536 void f(const T& t, const int i) { }
20538 Note that when the template is first instantiated, with
20539 instantiate_template, the resulting DECL will have no name for the
20540 first parameter, and the wrong type for the second. So, when we go
20541 to instantiate the DECL, we regenerate it. */
20543 static void
20545 {
20546 /* The arguments used to instantiate DECL, from the most general
20547 template. */
20548 tree args;
20549 tree code_pattern;
20554 /* Make sure that we can see identifiers, and compute access
20555 correctly. */
20559 {
20560 tree decl_parm;
20561 tree pattern_parm;
20562 tree specs;
20576 specs);
20578 /* Merge parameter declarations. */
20581 pattern_parm
20585 {
20586 tree parm_type;
20587 tree attributes;
20592 NULL_TREE);
20598 {
20601 }
20604 }
20605 /* Merge any parameters that match with the function parameter
20606 pack. */
20608 {
20610 tree expanded_types;
20611 /* Expand the TYPE_PACK_EXPANSION that provides the types for
20612 the parameters in this function parameter pack. */
20617 {
20618 tree parm_type;
20619 tree attributes;
20622 /* Rename the parameter to include the index. */
20631 {
20634 }
20636 }
20637 }
20638 /* Merge additional specifiers from the CODE_PATTERN. */
20642 }
20644 {
20652 }
20653 else
20657 }
20659 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
20660 substituted to get DECL. */
20662 tree
20664 {
20667 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
20668 for the instantiation. This is not always the most general
20669 template. Consider, for example:
20671 template <class T>
20672 struct S { template <class U> void f();
20673 template <> void f<int>(); };
20675 and an instantiation of S<double>::f<int>. We want TD to be the
20676 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
20678 more general template. */
20680 /* We must also deal with friend templates. Given:
20682 template <class T> struct S {
20683 template <class U> friend void f() {};
20684 };
20686 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
20687 so far as the language is concerned, but that's still
20688 where we get the pattern for the instantiation from. On
20689 other hand, if the definition comes outside the class, say:
20691 template <class T> struct S {
20692 template <class U> friend void f();
20693 };
20694 template <class U> friend void f() {}
20696 we don't need to look any further. That's what the check for
20697 DECL_INITIAL is for. */
20701 {
20702 /* The present template, TD, should not be a definition. If it
20703 were a definition, we should be using it! Note that we
20704 cannot restructure the loop to just keep going until we find
20705 a template with a definition, since that might go too far if
20706 a specialization was declared, but not defined. */
20708 /* Fetch the more general template. */
20710 }
20713 }
20715 /* Returns true if we need to instantiate this template instance even if we
20716 know we aren't going to emit it. */
20718 bool
20720 {
20721 /* We always instantiate inline functions so that we can inline them. An
20722 explicit instantiation declaration prohibits implicit instantiation of
20723 non-inline functions. With high levels of optimization, we would
20724 normally inline non-inline functions -- but we're not allowed to do
20725 that for "extern template" functions. Therefore, we check
20726 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
20730 /* And we need to instantiate static data members so that
20731 their initializers are available in integral constant
20732 expressions. */
20735 }
20737 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
20738 instantiate it now, modifying TREE_TYPE (fn). */
20740 void
20742 {
20745 /* Don't instantiate a noexcept-specification from template context. */
20760 {
20764 {
20779 }
20780 else
20784 }
20787 {
20790 else
20792 }
20793 }
20795 /* Produce the definition of D, a _DECL generated from a template. If
20796 DEFER_OK is nonzero, then we don't have to actually do the
20797 instantiation now; we just have to do it sometime. Normally it is
20798 an error if this is an explicit instantiation but D is undefined.
20799 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
20800 explicitly instantiated class template. */
20802 tree
20805 {
20807 tree gen_args;
20808 tree args;
20809 tree td;
20810 tree code_pattern;
20811 tree spec;
20812 tree gen_tmpl;
20819 tree fn_context;
20822 /* This function should only be used to instantiate templates for
20823 functions and static member variables. */
20826 /* A concept is never instantiated. */
20829 /* Variables are never deferred; if instantiation is required, they
20830 are instantiated right away. That allows for better code in the
20831 case that an expression refers to the value of the variable --
20832 if the variable has a constant value the referring expression can
20833 take advantage of that fact. */
20838 /* Don't instantiate cloned functions. Instead, instantiate the
20839 functions they cloned. */
20847 /* D has already been instantiated or explicitly specialized, so
20848 there's nothing for us to do here.
20850 It might seem reasonable to check whether or not D is an explicit
20851 instantiation, and, if so, stop here. But when an explicit
20852 instantiation is deferred until the end of the compilation,
20853 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
20854 the instantiation. */
20857 /* Check to see whether we know that this template will be
20858 instantiated in some other file, as with "extern template"
20859 extension. */
20862 /* In general, we do not instantiate such templates. */
20870 /* We should already have the extra args. */
20873 /* And what's in the hash table should match D. */
20877 /* This needs to happen before any tsubsting. */
20883 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
20884 for the instantiation. */
20888 /* We should never be trying to instantiate a member of a class
20889 template or partial specialization. */
20894 /* In the case of a friend template whose definition is provided
20895 outside the class, we may have too many arguments. Drop the
20896 ones we don't need. The same is true for specializations. */
20897 args = get_innermost_template_args
20899 else
20903 {
20908 }
20909 else
20910 {
20913 }
20915 /* We may be in the middle of deferred access check. Disable it now. */
20918 /* Unless an explicit instantiation directive has already determined
20919 the linkage of D, remember that a definition is available for
20920 this entity. */
20930 /* If D is a member of an explicitly instantiated class template,
20931 and no definition is available, treat it like an implicit
20932 instantiation. */
20935 {
20936 /* Leave linkage flags alone on instantiations with anonymous
20937 visibility. */
20939 {
20942 }
20944 }
20946 /* Defer all other templates, unless we have been explicitly
20947 forbidden from doing so. */
20949 template. */
20950 ! pattern_defined
20951 /* If it's OK to postpone instantiation, do so. */
20952 || defer_ok
20953 /* If this is a static data member that will be defined
20954 elsewhere, we don't want to instantiate the entire data
20955 member, but we do want to instantiate the initializer so that
20956 we can substitute that elsewhere. */
20958 /* Handle here a deleted function too, avoid generating
20959 its body (c++/61080). */
20961 {
20962 /* The definition of the static data member is now required so
20963 we must substitute the initializer. */
20967 {
20968 tree ns;
20969 tree init;
20978 args,
20981 /* If instantiating the initializer involved instantiating this
20982 again, don't call cp_finish_decl twice. */
20984 {
20985 /* Make sure the initializer is still constant, in case of
20986 circular dependency (template/instantiate6.C). */
20987 const_init
20991 LOOKUP_ONLYCONVERTING);
20992 }
20996 }
20998 /* We restore the source position here because it's used by
20999 add_pending_template. */
21005 /* [temp.explicit]
21007 The definition of a non-exported function template, a
21008 non-exported member function template, or a non-exported
21009 member function or static data member of a class template
21010 shall be present in every translation unit in which it is
21011 explicitly instantiated. */
21015 /* If we're in unevaluated context, we just wanted to get the
21016 constant value; this isn't an odr use, so don't queue
21017 a full instantiation. */
21020 /* ??? Historically, we have instantiated inline functions, even
21021 when marked as "extern template". */
21025 }
21026 /* Tell the repository that D is available in this translation unit
21027 -- and see if it is supposed to be instantiated here. */
21029 {
21030 /* In a PCH file, despite the fact that the repository hasn't
21031 requested instantiation in the PCH it is still possible that
21032 an instantiation will be required in a file that includes the
21033 PCH. */
21036 /* Instantiate inline functions so that the inliner can do its
21037 job, even though we'll not be emitting a copy of this
21038 function. */
21041 }
21047 else
21048 {
21053 }
21055 /* Mark D as instantiated so that recursive calls to
21056 instantiate_decl do not try to instantiate it again. */
21059 /* Regenerate the declaration in case the template has been modified
21060 by a subsequent redeclaration. */
21063 /* We already set the file and line above. Reset them now in case
21064 they changed as a result of calling regenerate_decl_from_template. */
21068 {
21069 tree init;
21072 /* Clear out DECL_RTL; whatever was there before may not be right
21073 since we've reset the type of the declaration. */
21077 /* The initializer is placed in DECL_INITIAL by
21078 regenerate_decl_from_template so we don't need to
21079 push/pop_access_scope again here. Pull it out so that
21080 cp_finish_decl can process it. */
21085 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
21086 initializer. That function will defer actual emission until
21087 we have a chance to determine linkage. */
21090 /* Enter the scope of D so that access-checking works correctly. */
21103 }
21107 {
21109 tree subst_decl;
21110 tree tmpl_parm;
21111 tree spec_parm;
21114 /* Save away the current list, in case we are instantiating one
21115 template from within the body of another. */
21118 /* Set up the list of local specializations. */
21121 /* Set up context. */
21125 else
21128 /* Some typedefs referenced from within the template code need to be
21129 access checked at template instantiation time, i.e now. These
21130 types were added to the template at parsing time. Let's get those
21131 and perform the access checks then. */
21133 gen_args);
21135 /* Create substitution entries for the parameters. */
21140 {
21144 }
21146 {
21148 {
21151 }
21152 else
21153 {
21154 /* Register the (value) argument pack as a specialization of
21155 TMPL_PARM, then move on. */
21158 }
21159 }
21162 /* Substitute into the body of the function. */
21166 else
21167 {
21172 /* Set the current input_location to the end of the function
21173 so that finish_function knows where we are. */
21174 input_location
21177 /* Remember if we saw an infinite loop in the template. */
21178 current_function_infinite_loop
21180 }
21182 /* We don't need the local specializations any more. */
21186 /* Finish the function. */
21190 else
21191 {
21194 }
21198 }
21200 /* We're not deferring instantiation any more. */
21208 out:
21218 }
21220 /* Run through the list of templates that we wish we could
21221 instantiate, and instantiate any we can. RETRIES is the
21222 number of times we retry pending template instantiation. */
21224 void
21226 {
21230 /* Instantiating templates may trigger vtable generation. This in turn
21231 may require further template instantiations. We place a limit here
21232 to avoid infinite loop. */
21234 {
21238 "template instantiation depth exceeds maximum of %d"
21239 " instantiating %q+D, possibly from virtual table generation"
21243 /* Pretend that we defined it. */
21246 }
21248 do
21249 {
21254 {
21259 {
21260 tree fn;
21263 {
21267 fn;
21275 }
21278 }
21279 else
21280 {
21283 {
21284 instantiation
21290 }
21294 }
21297 /* If INSTANTIATION has been instantiated, then we don't
21298 need to consider it again in the future. */
21300 else
21301 {
21304 }
21307 }
21309 }
21313 }
21315 /* Substitute ARGVEC into T, which is a list of initializers for
21316 either base class or a non-static data member. The TREE_PURPOSEs
21317 are DECLs, and the TREE_VALUEs are the initializer values. Used by
21318 instantiate_decl. */
21320 static tree
21322 {
21326 {
21327 tree decl;
21328 tree init;
21334 {
21335 tree expr;
21336 tree arg;
21338 /* Expand the base class expansion type into separate base
21339 classes. */
21341 tf_warning_or_error,
21342 NULL_TREE);
21346 /* We'll be building separate TREE_LISTs of arguments for
21347 each base. */
21353 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
21354 expand each argument in the TREE_VALUE of t. */
21361 /* VOID_TYPE_NODE is used to indicate
21362 value-initialization. */
21363 {
21366 }
21367 else
21368 {
21369 /* Substitute parameter packs into each argument in the
21370 TREE_LIST. */
21373 {
21374 tree expanded_exprs;
21376 /* Expand the argument. */
21378 expanded_exprs
21380 tf_warning_or_error,
21381 NULL_TREE);
21385 /* Prepend each of the expanded expressions to the
21386 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
21388 {
21393 }
21394 }
21397 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
21398 since we built them backwards. */
21400 {
21403 }
21404 }
21405 }
21408 {
21410 {
21414 }
21415 else
21416 {
21417 tree tmp;
21432 /* If we had an initializer but it instantiated to nothing,
21433 value-initialize the object. This will only occur when
21434 the initializer was a pack expansion where the parameter
21435 packs used in that expansion were of length zero. */
21438 }
21441 {
21445 }
21446 }
21447 }
21449 }
21451 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
21453 static void
21455 {
21460 else
21462 }
21464 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
21465 is the instantiation (which should have been created with
21466 start_enum) and ARGS are the template arguments to use. */
21468 static void
21470 {
21471 tree e;
21477 {
21478 tree value;
21479 tree decl;
21482 /* Note that in a template enum, the TREE_VALUE is the
21483 CONST_DECL, not the corresponding INTEGER_CST. */
21488 /* Give this enumeration constant the correct access. */
21491 /* Actually build the enumerator itself. Here we're assuming that
21492 enumerators can't have dependent attributes. */
21495 }
21505 }
21507 /* DECL is a FUNCTION_DECL that is a template specialization. Return
21508 its type -- but without substituting the innermost set of template
21509 arguments. So, innermost set of template parameters will appear in
21510 the type. */
21512 tree
21514 {
21515 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
21517 }
21519 /* Return truthvalue if we're processing a template different from
21520 the last one involved in diagnostics. */
21521 bool
21523 {
21525 }
21527 /* Remember current template involved in diagnostics. */
21528 void
21530 {
21532 }
21536 {
21538 }
21540 /* Return TRUE if current_function_decl is being instantiated, false
21541 otherwise. */
21543 bool
21545 {
21548 }
21550 /* [temp.param] Check that template non-type parm TYPE is of an allowable
21551 type. Return zero for ok, nonzero for disallowed. Issue error and
21552 warning messages under control of COMPLAIN. */
21554 static int
21556 {
21571 /* A bound template template parm could later be instantiated to have a valid
21572 nontype parm type via an alias template. */
21578 {
21581 else
21583 type);
21584 }
21586 }
21588 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
21589 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
21591 static bool
21593 {
21594 tree scope;
21596 /* [temp.dep.type]
21598 A type is dependent if it is:
21600 -- a template parameter. Template template parameters are types
21601 for us (since TYPE_P holds true for them) so we handle
21602 them here. */
21606 /* -- a qualified-id with a nested-name-specifier which contains a
21607 class-name that names a dependent type or whose unqualified-id
21608 names a dependent type. */
21612 /* An alias template specialization can be dependent even if the
21613 resulting type is not. */
21617 /* -- a cv-qualified type where the cv-unqualified type is
21618 dependent.
21619 No code is necessary for this bullet; the code below handles
21620 cv-qualified types, and we don't want to strip aliases with
21621 TYPE_MAIN_VARIANT because of DR 1558. */
21622 /* -- a compound type constructed from any dependent type. */
21632 {
21633 tree arg_type;
21638 arg_type;
21643 }
21644 /* -- an array type constructed from any dependent type or whose
21645 size is specified by a constant expression that is
21646 value-dependent.
21648 We checked for type- and value-dependence of the bounds in
21649 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
21651 {
21656 }
21658 /* -- a template-id in which either the template name is a template
21659 parameter ... */
21662 /* ... or any of the template arguments is a dependent type or
21663 an expression that is type-dependent or value-dependent. */
21665 && (any_dependent_template_arguments_p
21669 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
21670 dependent; if the argument of the `typeof' expression is not
21671 type-dependent, then it should already been have resolved. */
21677 /* A template argument pack is dependent if any of its packed
21678 arguments are. */
21680 {
21686 }
21688 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
21689 be template parameters. */
21693 /* The standard does not specifically mention types that are local
21694 to template functions or local classes, but they should be
21695 considered dependent too. For example:
21697 template <int I> void f() {
21698 enum E { a = I };
21699 S<sizeof (E)> s;
21700 }
21702 The size of `E' cannot be known until the value of `I' has been
21703 determined. Therefore, `E' must be considered dependent. */
21707 /* Don't use type_dependent_expression_p here, as it can lead
21708 to infinite recursion trying to determine whether a lambda
21709 nested in a lambda is dependent (c++/47687). */
21713 && (any_dependent_template_arguments_p
21717 /* Other types are non-dependent. */
21719 }
21721 /* Returns TRUE if TYPE is dependent, in the sense of
21722 [temp.dep.type]. Note that a NULL type is considered dependent. */
21724 bool
21726 {
21727 /* If there are no template parameters in scope, then there can't be
21728 any dependent types. */
21730 {
21731 /* If we are not processing a template, then nobody should be
21732 providing us with a dependent type. */
21736 }
21738 /* If the type is NULL, we have not computed a type for the entity
21739 in question; in that case, the type is dependent. */
21743 /* Erroneous types can be considered non-dependent. */
21747 /* If we have not already computed the appropriate value for TYPE,
21748 do so now. */
21750 {
21753 }
21756 }
21758 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
21759 lookup. In other words, a dependent type that is not the current
21760 instantiation. */
21762 bool
21764 {
21767 }
21769 /* T is a SCOPE_REF; return whether we need to consider it
21770 instantiation-dependent so that we can check access at instantiation
21771 time even though we know which member it resolves to. */
21773 static bool
21775 {
21781 else
21783 }
21785 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
21786 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
21787 expression. */
21789 /* Note that this predicate is not appropriate for general expressions;
21790 only constant expressions (that satisfy potential_constant_expression)
21791 can be tested for value dependence. */
21793 bool
21795 {
21799 /* A name declared with a dependent type. */
21804 {
21806 /* A name that has not been looked up -- must be dependent. */
21810 /* A non-type template parm. */
21814 /* A non-type template parm. */
21820 /* A constant with literal type and is initialized
21821 with an expression that is value-dependent.
21823 Note that a non-dependent parenthesized initializer will have
21824 already been replaced with its constant value, so if we see
21825 a TREE_LIST it must be dependent. */
21829 /* cp_finish_decl doesn't fold reference initializers. */
21840 /* These expressions are value-dependent if the type to which
21841 the cast occurs is dependent or the expression being casted
21842 is value-dependent. */
21843 {
21849 /* A functional cast has a list of operands. */
21852 {
21853 /* If there are no operands, it must be an expression such
21854 as "int()". This should not happen for aggregate types
21855 because it would form non-constant expressions. */
21860 }
21866 }
21871 /* FALLTHRU */
21874 /* A `sizeof' expression is value-dependent if the operand is
21875 type-dependent or is a pack expansion. */
21884 /* An 'encode' expression is value-dependent if the operand is
21885 type-dependent. */
21894 /* All instantiation-dependent expressions should also be considered
21895 value-dependent. */
21903 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
21904 is value-dependent. */
21905 {
21914 }
21917 {
21921 }
21932 {
21936 }
21939 /* Treat all requires-expressions as value-dependent so
21940 we don't try to fold them. */
21947 {
21954 {
21956 /* In a call to a constexpr member function, look through the
21957 implicit ADDR_EXPR on the object argument so that it doesn't
21958 cause the call to be considered value-dependent. We also
21959 look through it in potential_constant_expression. */
21966 }
21968 }
21971 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
21972 type-dependent. */
21977 {
21979 tree val;
21986 }
21989 /* Treat a GNU statement expression as dependent to avoid crashing
21990 under instantiate_non_dependent_expr; it can't be constant. */
21994 /* A constant expression is value-dependent if any subexpression is
21995 value-dependent. */
21997 {
22004 {
22008 {
22011 /* In some cases, some of the operands may be missing.l
22012 (For example, in the case of PREDECREMENT_EXPR, the
22013 amount to increment by may be missing.) That doesn't
22014 make the expression dependent. */
22017 }
22018 }
22022 }
22024 }
22026 /* The expression is not value-dependent. */
22028 }
22030 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
22031 [temp.dep.expr]. Note that an expression with no type is
22032 considered dependent. Other parts of the compiler arrange for an
22033 expression with type-dependent subexpressions to have no type, so
22034 this function doesn't have to be fully recursive. */
22036 bool
22038 {
22045 /* An unresolved name is always dependent. */
22051 /* Some expression forms are never type-dependent. */
22065 /* The types of these expressions depends only on the type to which
22066 the cast occurs. */
22075 /* The types of these expressions depends only on the type created
22076 by the expression. */
22079 {
22080 /* For NEW_EXPR tree nodes created inside a template, either
22081 the object type itself or a TREE_LIST may appear as the
22082 operand 1. */
22085 /* This is an array type. We need to check array dimensions
22086 as well. */
22088 || value_dependent_expression_p
22090 else
22092 }
22095 {
22099 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
22100 contains an identifier associated by name lookup with one or more
22101 declarations declared with a dependent type, or...a
22102 nested-name-specifier or qualified-id that names a member of an
22103 unknown specialization. */
22106 }
22111 && (any_dependent_template_arguments_p
22123 {
22124 tree elt;
22128 {
22131 }
22133 }
22135 /* A static data member of the current instantiation with incomplete
22136 array type is type-dependent, as the definition and specializations
22137 can have different bounds. */
22144 /* An array of unknown bound depending on a variadic parameter, eg:
22146 template<typename... Args>
22147 void foo (Args... args)
22148 {
22149 int arr[] = { args... };
22150 }
22152 template<int... vals>
22153 void bar ()
22154 {
22155 int arr[] = { vals... };
22156 }
22158 If the array has no length and has an initializer, it must be that
22159 we couldn't determine its length in cp_complete_array_type because
22160 it is dependent. */
22167 /* A variable template specialization is type-dependent if it has any
22168 dependent template arguments. */
22175 /* Always dependent, on the number of arguments if nothing else. */
22180 {
22185 {
22191 }
22192 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
22197 {
22202 }
22205 {
22212 }
22218 {
22222 }
22224 }
22229 }
22231 /* walk_tree callback function for instantiation_dependent_expression_p,
22232 below. Returns non-zero if a dependent subexpression is found. */
22234 static tree
22237 {
22239 {
22240 /* We don't have to worry about decltype currently because decltype
22241 of an instantiation-dependent expr is a dependent type. This
22242 might change depending on the resolution of DR 1172. */
22245 }
22248 {
22249 /* Don't treat an argument list as dependent just because it has no
22250 TREE_TYPE. */
22257 /* A constant with a dependent initializer is dependent. */
22265 /* Handle expressions with type operands. */
22270 {
22275 {
22278 else
22279 {
22282 }
22283 }
22285 }
22295 /* In a template, finish_class_member_access_expr creates a
22296 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
22297 type-dependent, so that we can check access control at
22298 instantiation time (PR 42277). See also Core issue 1273. */
22305 else
22308 /* Treat statement-expressions as dependent. */
22312 /* Treat requires-expressions as dependent. */
22317 /* Treat calls to function concepts as dependent. */
22323 /* And variable concepts. */
22330 }
22334 else
22336 }
22338 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
22339 sense defined by the ABI:
22341 "An expression is instantiation-dependent if it is type-dependent
22342 or value-dependent, or it has a subexpression that is type-dependent
22343 or value-dependent." */
22345 bool
22347 {
22348 tree result;
22359 }
22361 /* Like type_dependent_expression_p, but it also works while not processing
22362 a template definition, i.e. during substitution or mangling. */
22364 bool
22366 {
22372 }
22374 /* Returns TRUE if ARGS contains a type-dependent expression. */
22376 bool
22378 {
22380 tree arg;
22383 {
22386 }
22388 }
22390 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
22391 expressions) contains any type-dependent expressions. */
22393 bool
22395 {
22401 }
22403 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
22404 expressions) contains any value-dependent expressions. */
22406 bool
22408 {
22414 }
22416 /* Returns TRUE if the ARG (a template argument) is dependent. */
22418 bool
22420 {
22424 /* Assume a template argument that was wrongly written by the user
22425 is dependent. This is consistent with what
22426 any_dependent_template_arguments_p [that calls this function]
22427 does. */
22438 {
22442 {
22445 }
22448 }
22451 else
22454 }
22456 /* Returns true if ARGS (a collection of template arguments) contains
22457 any types that require structural equality testing. */
22459 bool
22461 {
22471 {
22474 {
22480 {
22481 /* Look inside the argument pack. */
22484 }
22487 {
22500 }
22501 }
22502 }
22505 }
22507 /* Returns true if ARGS (a collection of template arguments) contains
22508 any dependent arguments. */
22510 bool
22512 {
22522 {
22527 }
22530 }
22532 /* Returns TRUE if the template TMPL is dependent. */
22534 bool
22536 {
22538 {
22540 {
22544 }
22546 }
22548 /* Template template parameters are dependent. */
22552 /* So are names that have not been looked up. */
22555 /* So are member templates of dependent classes. */
22559 }
22561 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
22563 bool
22565 {
22568 }
22570 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
22571 is dependent. */
22573 bool
22575 {
22582 {
22603 {
22607 }
22611 {
22615 {
22620 }
22621 }
22622 }
22625 }
22627 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
22628 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
22629 no such TYPE can be found. Note that this function peers inside
22630 uninstantiated templates and therefore should be used only in
22631 extremely limited situations. ONLY_CURRENT_P restricts this
22632 peering to the currently open classes hierarchy (which is required
22633 when comparing types). */
22635 tree
22637 {
22638 tree scope;
22639 tree name;
22640 tree decl;
22642 tree pushed_scope;
22643 tree result;
22648 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
22649 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
22650 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
22651 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
22652 identifier of the TYPENAME_TYPE anymore.
22653 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
22654 TYPENAME_TYPE instead, we avoid messing up with a possible
22655 typedef variant case. */
22658 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
22659 it first before we can figure out what NAME refers to. */
22661 {
22663 /* Given a class template A with a dependent base with nested type C,
22664 typedef typename A::C::C C will land us here, as trying to resolve
22665 the initial A::C leads to the local C typedef, which leads back to
22666 A::C::C. So we break the recursion now. */
22668 else
22670 }
22671 /* If we don't know what SCOPE refers to, then we cannot resolve the
22672 TYPENAME_TYPE. */
22675 /* If the SCOPE is a template type parameter, we have no way of
22676 resolving the name. */
22679 /* If the SCOPE is not the current instantiation, there's no reason
22680 to look inside it. */
22683 /* If this is a typedef, we don't want to look inside (c++/11987). */
22686 /* If SCOPE isn't the template itself, it will not have a valid
22687 TYPE_FIELDS list. */
22690 /* scope is either the template itself or a compatible instantiation
22691 like X<T>, so look up the name in the original template. */
22693 else
22694 /* scope is a partial instantiation, so we can't do the lookup or we
22695 will lose the template arguments. */
22697 /* Enter the SCOPE so that name lookup will be resolved as if we
22698 were in the class definition. In particular, SCOPE will no
22699 longer be considered a dependent type. */
22701 /* Look up the declaration. */
22703 tf_warning_or_error);
22707 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
22708 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
22713 {
22717 }
22720 {
22721 tree tmpl;
22722 tree args;
22723 /* Obtain the template and the arguments. */
22726 /* Instantiate the template. */
22732 }
22734 /* Leave the SCOPE. */
22738 /* If we failed to resolve it, return the original typename. */
22742 /* If lookup found a typename type, resolve that too. */
22744 {
22745 /* Ill-formed programs can cause infinite recursion here, so we
22746 must catch that. */
22750 }
22752 /* Qualify the resulting type. */
22758 }
22760 /* EXPR is an expression which is not type-dependent. Return a proxy
22761 for EXPR that can be used to compute the types of larger
22762 expressions containing EXPR. */
22764 tree
22766 {
22767 tree inner_expr;
22769 #ifdef ENABLE_CHECKING
22770 /* Try to get a constant value for all non-dependent expressions in
22771 order to expose bugs in *_dependent_expression_p and constexpr. */
22774 #endif
22776 /* Preserve OVERLOADs; the functions must be available to resolve
22777 types. */
22788 /* There is no need to return a proxy for a variable. */
22791 /* Preserve string constants; conversions from string constants to
22792 "char *" are allowed, even though normally a "const char *"
22793 cannot be used to initialize a "char *". */
22796 /* Preserve void and arithmetic constants, as an optimization -- there is no
22797 reason to create a new node. */
22802 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
22803 There is at least one place where we want to know that a
22804 particular expression is a throw-expression: when checking a ?:
22805 expression, there are special rules if the second or third
22806 argument is a throw-expression. */
22810 /* Don't wrap an initializer list, we need to be able to look inside. */
22814 /* Don't wrap a dummy object, we need to be able to test for it. */
22833 /* If the type is unknown, it can't really be non-dependent */
22836 /* Otherwise, build a NON_DEPENDENT_EXPR. */
22838 }
22840 /* ARGS is a vector of expressions as arguments to a function call.
22841 Replace the arguments with equivalent non-dependent expressions.
22842 This modifies ARGS in place. */
22844 void
22846 {
22848 tree arg;
22851 {
22855 }
22856 }
22858 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
22859 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
22860 parms. */
22862 static tree
22864 {
22877 }
22879 tree
22881 {
22883 }
22885 tree
22887 {
22889 }
22891 /* Given type ARG, return std::initializer_list<ARG>. */
22893 static tree
22895 {
22896 tree std_init_list = namespace_binding
22898 tree argvec;
22900 {
22904 }
22909 }
22911 /* Replace auto in TYPE with std::initializer_list<auto>. */
22913 static tree
22915 {
22922 }
22924 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
22925 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
22927 tree
22929 {
22931 tf_warning_or_error,
22932 adc_unspecified);
22933 }
22935 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
22936 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
22937 The CONTEXT determines the context in which auto deduction is performed
22938 and is used to control error diagnostics. */
22940 tree
22943 {
22944 tree targs;
22950 /* Defining a subset of type-dependent expressions that we can deduce
22951 from ahead of time isn't worth the trouble. */
22954 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
22955 with either a new invented type template parameter U or, if the
22956 initializer is a braced-init-list (8.5.4), with
22957 std::initializer_list<U>. */
22959 {
22964 else
22965 {
22967 {
22971 "for deduction to %<std::initializer_list%>, use copy-"
22973 }
22975 }
22976 }
22982 {
22988 {
22992 }
22993 }
22994 else
22995 {
23006 {
23008 /* Try again at instantiation time. */
23012 /* If type is error_mark_node a diagnostic must have been
23013 emitted by now. Also, having a mention to '<type error>'
23014 in the diagnostic is not really useful to the user. */
23015 {
23019 else
23021 }
23023 }
23024 }
23026 /* If the list of declarators contains more than one declarator, the type
23027 of each declared variable is determined as described above. If the
23028 type deduced for the template parameter U is not the same in each
23029 deduction, the program is ill-formed. */
23032 {
23038 else
23042 }
23046 /* Check any placeholder constraints against the deduced type. */
23049 {
23050 /* Use the deduced type to check the associated constraints. */
23052 {
23054 {
23056 {
23072 }
23074 }
23076 }
23077 }
23082 }
23084 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
23085 result. */
23087 tree
23089 {
23091 {
23097 /* In an abbreviated function template we didn't know we were dealing
23098 with a function template when we saw the auto return type, so update
23099 it to have the correct level. */
23101 }
23103 }
23105 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
23106 'decltype(auto)'. */
23108 bool
23110 {
23115 else
23117 }
23119 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
23120 a use of `auto'. Returns NULL_TREE otherwise. */
23122 tree
23124 {
23126 }
23128 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
23129 'decltype(auto)' or a concept. */
23131 bool
23133 {
23135 }
23137 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
23138 a concept identifier) iff TYPE contains a use of a generic type. Returns
23139 NULL_TREE otherwise. */
23141 tree
23143 {
23145 }
23148 /* For a given template T, return the vector of typedefs referenced
23149 in T for which access check is needed at T instantiation time.
23150 T is either a FUNCTION_DECL or a RECORD_TYPE.
23151 Those typedefs were added to T by the function
23152 append_type_to_template_for_access_check. */
23156 {
23157 tree ti;
23168 {
23173 }
23176 }
23178 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
23179 tied to T. That list of typedefs will be access checked at
23180 T instantiation time.
23181 T is either a FUNCTION_DECL or a RECORD_TYPE.
23182 TYPE_DECL is a TYPE_DECL node representing a typedef.
23183 SCOPE is the scope through which TYPE_DECL is accessed.
23184 LOCATION is the location of the usage point of TYPE_DECL.
23186 This function is a subroutine of
23187 append_type_to_template_for_access_check. */
23189 static void
23191 tree type_decl,
23192 tree scope,
23193 location_t location)
23194 {
23195 qualified_typedef_usage_t typedef_usage;
23196 tree ti;
23203 && type_decl
23217 }
23219 /* Append TYPE_DECL to the template TEMPL.
23220 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
23221 At TEMPL instanciation time, TYPE_DECL will be checked to see
23222 if it can be accessed through SCOPE.
23223 LOCATION is the location of the usage point of TYPE_DECL.
23225 e.g. consider the following code snippet:
23227 class C
23228 {
23229 typedef int myint;
23230 };
23232 template<class U> struct S
23233 {
23234 C::myint mi; // <-- usage point of the typedef C::myint
23235 };
23237 S<char> s;
23239 At S<char> instantiation time, we need to check the access of C::myint
23240 In other words, we need to check the access of the myint typedef through
23241 the C scope. For that purpose, this function will add the myint typedef
23242 and the scope C through which its being accessed to a list of typedefs
23243 tied to the template S. That list will be walked at template instantiation
23244 time and access check performed on each typedefs it contains.
23245 Note that this particular code snippet should yield an error because
23246 myint is private to C. */
23248 void
23250 tree type_decl,
23251 tree scope,
23252 location_t location)
23253 {
23259 /* Make sure we don't append the type to the template twice. */
23266 }
23268 /* Convert the generic type parameters in PARM that match the types given in the
23269 range [START_IDX, END_IDX) from the current_template_parms into generic type
23270 packs. */
23272 tree
23274 {
23285 {
23286 /* Create a distinct parameter pack type from the current parm and add it
23287 to the replacement args to tsubst below into the generic function
23288 parameter. */
23303 }
23309 /* If there are more levels then build up the replacement with the outer
23310 template parms. */
23314 replacement);
23317 }
23319 /* Entries in the decl_constraint hash table. */
23321 {
23322 tree decl;
23323 tree ci;
23324 };
23326 /* Hashing function and equality for constraint entries. */
23328 {
23330 {
23332 }
23335 {
23337 }
23338 };
23340 /* A mapping from declarations to constraint information. Note that
23341 both templates and their underlying declarations are mapped to the
23342 same constraint information.
23344 FIXME: This is defined in pt.c because garbage collection
23345 code is not being generated for constraint.cc. */
23349 /* Returns true iff cinfo contains a valid set of constraints.
23350 This is the case when the associated requirements have been
23351 successfully decomposed into lists of atomic constraints.
23352 That is, when the saved assumptions are not error_mark_node. */
23354 bool
23356 {
23359 }
23361 /* Returns the template constraints of declaration T. If T is not
23362 constrained, return NULL_TREE. Note that T must be non-null. */
23364 tree
23366 {
23374 else
23376 }
23378 /* Associate the given constraint information CI with the declaration
23379 T. If T is a template, then the constraints are associated with
23380 its underlying declaration. Don't build associations if CI is
23381 NULL_TREE. */
23383 void
23385 {
23397 }
23399 /* Remove the associated constraints of the declaration T. */
23401 void
23403 {
23412 }
23414 /* Set up the hash table for constraint association. */
23416 void
23418 {
23420 }
23422 /* Set up the hash tables for template instantiations. */
23424 void
23426 {
23429 }
23431 /* Print stats about the template hash tables for -fstats. */
23433 void
23435 {
23444 }