| blob | 281604594ada82d2bd6f18a0e3d2d7842e054df6 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 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". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
50 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
51 instantiations have been deferred, either because their definitions
52 were not yet available, or because we were putting off doing the work. */
56 };
71 /* Live only within one (recursive) call to tsubst_expr. We use
72 this to pass the statement expression node from the STMT_EXPR
73 to the EXPR_STMT that is its result. */
76 // -------------------------------------------------------------------------- //
77 // Local Specialization Stack
78 //
79 // Implementation of the RAII helper for creating new local
80 // specializations.
83 {
86 else
88 }
91 {
94 }
96 /* True if we've recursed into fn_type_unification too many times. */
100 {
101 tree tmpl;
102 tree args;
103 tree spec;
104 };
107 {
110 };
116 /* Contains canonical template parameter types. The vector is indexed by
117 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
118 TREE_LIST, whose TREE_VALUEs contain the canonical template
119 parameters of various types and levels. */
122 #define UNIFY_ALLOW_NONE 0
123 #define UNIFY_ALLOW_MORE_CV_QUAL 1
124 #define UNIFY_ALLOW_LESS_CV_QUAL 2
125 #define UNIFY_ALLOW_DERIVED 4
126 #define UNIFY_ALLOW_INTEGER 8
127 #define UNIFY_ALLOW_OUTER_LEVEL 16
128 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
129 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
132 tbr_incomplete_type,
133 tbr_ambiguous_baseclass,
134 tbr_success
135 };
158 tree);
215 location_t);
227 /* Make the current scope suitable for access checking when we are
228 processing T. T can be FUNCTION_DECL for instantiated function
229 template, VAR_DECL for static member variable, or TYPE_DECL for
230 alias template (needed by instantiate_decl). */
232 static void
234 {
242 else
246 {
247 saved_access_scope = tree_cons
250 }
251 }
253 /* Restore the scope set up by push_access_scope. T is the node we
254 are processing. */
256 static void
258 {
260 {
263 }
267 else
269 }
271 /* Do any processing required when DECL (a member template
272 declaration) is finished. Returns the TEMPLATE_DECL corresponding
273 to DECL, unless it is a specialization, in which case the DECL
274 itself is returned. */
276 tree
278 {
285 {
286 tree type;
294 {
298 }
300 }
304 {
306 {
309 }
310 else
312 }
313 else
317 }
319 /* Create a template info node. */
321 tree
323 {
328 }
330 /* Return the template info node corresponding to T, whatever T is. */
332 tree
334 {
356 }
358 /* Returns the template nesting level of the indicated class TYPE.
360 For example, in:
361 template <class T>
362 struct A
363 {
364 template <class U>
365 struct B {};
366 };
368 A<T>::B<U> has depth two, while A<T> has depth one.
369 Both A<T>::B<int> and A<int>::B<U> have depth one, if
370 they are instantiations, not specializations.
372 This function is guaranteed to return 0 if passed NULL_TREE so
373 that, for example, `template_class_depth (current_class_type)' is
374 always safe. */
376 int
378 {
382 {
393 else
395 }
398 }
400 /* Subroutine of maybe_begin_member_template_processing.
401 Returns true if processing DECL needs us to push template parms. */
403 static bool
405 {
411 }
413 /* Subroutine of maybe_begin_member_template_processing.
414 Push the template parms in PARMS, starting from LEVELS steps into the
415 chain, and ending at the beginning, since template parms are listed
416 innermost first. */
418 static void
420 {
428 current_template_parms
434 NULL);
436 {
445 {
452 /* Push the CONST_DECL. */
458 }
459 }
460 }
462 /* Restore the template parameter context for a member template, a
463 friend template defined in a class definition, or a non-template
464 member of template class. */
466 void
468 {
469 tree parms;
474 {
477 /* Disregard full specializations (c++/60999). */
480 }
483 {
488 {
491 }
494 }
496 /* Remember how many levels of template parameters we pushed so that
497 we can pop them later. */
499 }
501 /* Undo the effects of maybe_begin_member_template_processing. */
503 void
505 {
514 {
518 }
519 }
521 /* Return a new template argument vector which contains all of ARGS,
522 but has as its innermost set of arguments the EXTRA_ARGS. */
524 static tree
526 {
527 tree new_args;
545 }
547 /* Like add_to_template_args, but only the outermost ARGS are added to
548 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
549 (EXTRA_ARGS) levels are added. This function is used to combine
550 the template arguments from a partial instantiation with the
551 template arguments used to attain the full instantiation from the
552 partial instantiation. */
554 static tree
556 {
557 tree new_args;
559 /* If there are more levels of EXTRA_ARGS than there are ARGS,
560 something very fishy is going on. */
563 /* If *all* the new arguments will be the EXTRA_ARGS, just return
564 them. */
568 /* For the moment, we make ARGS look like it contains fewer levels. */
573 /* Now, we restore ARGS to its full dimensions. */
577 }
579 /* Return the N levels of innermost template arguments from the ARGS. */
581 tree
583 {
584 tree new_args;
590 /* If N is 1, just return the innermost set of template arguments. */
594 /* If we're not removing anything, just return the arguments we were
595 given. */
601 /* Make a new set of arguments, not containing the outer arguments. */
608 }
610 /* The inverse of get_innermost_template_args: Return all but the innermost
611 EXTRA_LEVELS levels of template arguments from the ARGS. */
613 static tree
615 {
616 tree new_args;
622 /* If N is 1, just return the outermost set of template arguments. */
626 /* If we're not removing anything, just return the arguments we were
627 given. */
632 /* Make a new set of arguments, not containing the inner arguments. */
639 }
641 /* We've got a template header coming up; push to a new level for storing
642 the parms. */
644 void
646 {
647 /* We use a non-tag-transparent scope here, which causes pushtag to
648 put tags in this scope, rather than in the enclosing class or
649 namespace scope. This is the right thing, since we want
650 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
651 global template class, push_template_decl handles putting the
652 TEMPLATE_DECL into top-level scope. For a nested template class,
653 e.g.:
655 template <class T> struct S1 {
656 template <class T> struct S2 {};
657 };
659 pushtag contains special code to insert the TEMPLATE_DECL for S2
660 at the right scope. */
666 /* Add a dummy parameter level while we process the parameter list. */
667 current_template_parms
670 current_template_parms);
671 }
673 /* This routine is called when a specialization is declared. If it is
674 invalid to declare a specialization here, an error is reported and
675 false is returned, otherwise this routine will return true. */
677 static bool
679 {
682 /* [temp.expl.spec]
684 An explicit specialization shall be declared in the namespace of
685 which the template is a member, or, for member templates, in the
686 namespace of which the enclosing class or enclosing class
687 template is a member. An explicit specialization of a member
688 function, member class or static data member of a class template
689 shall be declared in the namespace of which the class template
690 is a member. */
692 {
695 }
697 /* [temp.expl.spec]
699 In an explicit specialization declaration for a member of a class
700 template or a member template that appears in namespace scope,
701 the member template and some of its enclosing class templates may
702 remain unspecialized, except that the declaration shall not
703 explicitly specialize a class member template if its enclosing
704 class templates are not explicitly specialized as well. */
706 {
709 }
712 }
714 /* We've just seen template <>. */
716 bool
718 {
722 }
724 /* Called at then end of processing a declaration preceded by
725 template<>. */
727 void
729 {
732 }
734 /* Any template <>'s that we have seen thus far are not referring to a
735 function specialization. */
737 void
739 {
742 }
744 /* We've just seen a template header. If SPECIALIZATION is nonzero,
745 it was of the form template <>. */
747 static void
749 {
751 template_header_count++;
752 }
754 /* We're beginning an explicit instantiation. */
756 void
758 {
761 }
764 void
766 {
769 }
771 /* An explicit specialization or partial specialization of TMPL is being
772 declared. Check that the namespace in which the specialization is
773 occurring is permissible. Returns false iff it is invalid to
774 specialize TMPL in the current namespace. */
776 static bool
778 {
781 /* [tmpl.expl.spec]
783 An explicit specialization shall be declared in a namespace enclosing the
784 specialized template. An explicit specialization whose declarator-id is
785 not qualified shall be declared in the nearest enclosing namespace of the
786 template, or, if the namespace is inline (7.3.1), any namespace from its
787 enclosing namespace set. */
790 {
793 }
796 /* Same or enclosing namespace. */
798 else
799 {
805 }
806 }
808 /* SPEC is an explicit instantiation. Check that it is valid to
809 perform this explicit instantiation in the current namespace. */
811 static void
813 {
814 tree ns;
816 /* DR 275: An explicit instantiation shall appear in an enclosing
817 namespace of its template. */
823 }
825 // Returns the type of a template specialization only if that
826 // specialization needs to be defined. Otherwise (e.g., if the type has
827 // already been defined), the function returns NULL_TREE.
828 static tree
830 {
831 // An implicit instantiation of an incomplete type implies
832 // the definition of a new class template.
833 //
834 // template<typename T>
835 // struct S;
836 //
837 // template<typename T>
838 // struct S<T*>;
839 //
840 // Here, S<T*> is an implicit instantiation of S whose type
841 // is incomplete.
845 // It can also be the case that TYPE is a completed specialization.
846 // Continuing the previous example, suppose we also declare:
847 //
848 // template<typename T>
849 // requires Integral<T>
850 // struct S<T*>;
851 //
852 // Here, S<T*> refers to the specialization S<T*> defined
853 // above. However, we need to differentiate definitions because
854 // we intend to define a new partial specialization. In this case,
855 // we rely on the fact that the constraints are different for
856 // this declaration than that above.
857 //
858 // Note that we also get here for injected class names and
859 // late-parsed template definitions. We must ensure that we
860 // do not create new type declarations for those cases.
862 {
866 // If there are no template parameters, this cannot be a new
867 // partial template specializtion?
871 // The injected-class-name is not a new partial specialization.
875 // If the constraints are not the same as those of the primary
876 // then, we can probably create a new specialization.
880 {
884 }
886 // Also, if there's a pre-existing specialization with matching
887 // constraints, then this also isn't new.
890 {
898 }
900 // Create a new type node (and corresponding type decl)
901 // for the newly declared specialization.
906 /* We only need a separate type node for storing the definition of this
907 partial specialization; uses of S<T*> are unconstrained, so all are
908 equivalent. So keep TYPE_CANONICAL the same. */
911 // Build the corresponding type decl.
917 }
920 }
922 /* The TYPE is being declared. If it is a template type, that means it
923 is a partial specialization. Do appropriate error-checking. */
925 tree
927 {
928 tree context;
933 /* A lambda that appears in specialization context is not itself a
934 specialization. */
939 {
943 }
948 {
954 else
957 }
959 {
960 /* This is for ordinary explicit specialization and partial
961 specialization of a template class such as:
963 template <> class C<int>;
965 or:
967 template <class T> class C<T*>;
969 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
972 {
979 {
984 }
985 }
991 /* Trying to define a specialization either without a template<> header
992 or in an inappropriate place. We've already given an error, so just
993 bail now so we don't actually define the specialization. */
995 }
1001 {
1002 /* This is for an explicit specialization of member class
1003 template according to [temp.expl.spec/18]:
1005 template <> template <class U> class C<int>::D;
1007 The context `C<int>' must be an implicit instantiation.
1008 Otherwise this is just a member class template declared
1009 earlier like:
1011 template <> class C<int> { template <class U> class D; };
1012 template <> template <class U> class C<int>::D;
1014 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1015 while in the second case, `C<int>::D' is a primary template
1016 and `C<T>::D' may not exist. */
1020 {
1021 tree t;
1026 {
1031 }
1033 /* Check for invalid specialization after instantiation:
1035 template <> template <> class C<int>::D<int>;
1036 template <> template <class U> class C<int>::D; */
1040 {
1044 {
1045 /* We already have a full specialization of this partial
1046 instantiation, or a full specialization has been
1047 looked up but not instantiated. Reassign it to the
1048 new member specialization template. */
1049 spec_entry elt;
1061 spec_entry **slot
1066 }
1067 else
1068 /* But if we've had an implicit instantiation, that's a
1069 problem ([temp.expl.spec]/6). */
1072 }
1074 /* Mark TYPE as a specialization. And as a result, we only
1075 have one level of template argument for the innermost
1076 class template. */
1081 }
1082 }
1084 {
1085 /* Someday C++0x may allow for enum template specialization. */
1090 else
1091 {
1094 }
1095 }
1098 }
1100 /* Returns nonzero if we can optimize the retrieval of specializations
1101 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1102 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1106 {
1109 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1110 parameter. */
1112 /* The optimized lookup depends on the fact that the
1113 template arguments for the member function template apply
1114 purely to the containing class, which is not true if the
1115 containing class is an explicit or partial
1116 specialization. */
1120 /* It is possible to have a template that is not a member
1121 template and is not a member of a template class:
1123 template <typename T>
1124 struct S { friend A::f(); };
1126 Here, the friend function is a template, but the context does
1127 not have template information. The optimized lookup relies
1128 on having ARGS be the template arguments for both the class
1129 and the function template. */
1131 }
1133 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1134 gone through coerce_template_parms by now. */
1136 static void
1138 {
1141 {
1144 {
1151 /* Allow typedefs on the type of a non-type argument, since a
1153 else
1155 }
1156 }
1158 }
1160 /* Retrieve the specialization (in the sense of [temp.spec] - a
1161 specialization is either an instantiation or an explicit
1162 specialization) of TMPL for the given template ARGS. If there is
1163 no such specialization, return NULL_TREE. The ARGS are a vector of
1164 arguments, or a vector of vectors of arguments, in the case of
1165 templates with more than one level of parameters.
1167 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1168 then we search for a partial specialization matching ARGS. This
1169 parameter is ignored if TMPL is not a class template.
1171 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1172 result is a NONTYPE_ARGUMENT_PACK. */
1174 static tree
1176 {
1186 /* There should be as many levels of arguments as there are
1187 levels of parameters. */
1196 /* Lambda functions in templates aren't instantiated normally, but through
1197 tsubst_lambda_expr. */
1202 {
1203 /* The template arguments actually apply to the containing
1204 class. Find the class specialization with those
1205 arguments. */
1207 tree class_specialization
1212 /* Find the instance of TMPL. */
1215 {
1218 /* using-declarations can add base methods to the method vec,
1219 and we don't want those here. */
1222 }
1224 }
1225 else
1226 {
1228 spec_entry elt;
1237 else
1245 }
1248 }
1250 /* Like retrieve_specialization, but for local declarations. */
1252 tree
1254 {
1260 }
1262 /* Returns nonzero iff DECL is a specialization of TMPL. */
1264 int
1266 {
1267 tree t;
1270 {
1276 }
1277 else
1278 {
1287 }
1290 }
1292 /* Returns nonzero iff DECL is a specialization of friend declaration
1293 FRIEND_DECL according to [temp.friend]. */
1295 bool
1297 {
1304 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1305 of a template class, we want to check if DECL is a specialization
1306 if this. */
1310 {
1311 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1314 }
1319 /* There is nothing to do if this is not a template friend. */
1326 /* [temp.friend/6]
1327 A member of a class template may be declared to be a friend of a
1328 non-template class. In this case, the corresponding member of
1329 every specialization of the class template is a friend of the
1330 class granting friendship.
1332 For example, given a template friend declaration
1334 template <class T> friend void A<T>::f();
1336 the member function below is considered a friend
1338 template <> struct A<int> {
1339 void f();
1340 };
1342 For this type of template friend, TEMPLATE_DEPTH below will be
1343 nonzero. To determine if DECL is a friend of FRIEND, we first
1344 check if the enclosing class is a specialization of another. */
1351 {
1352 /* Next, we check the members themselves. In order to handle
1353 a few tricky cases, such as when FRIEND_DECL's are
1355 template <class T> friend void A<T>::g(T t);
1356 template <class T> template <T t> friend void A<T>::h();
1358 and DECL's are
1360 void A<int>::g(int);
1361 template <int> void A<int>::h();
1363 we need to figure out ARGS, the template arguments from
1364 the context of DECL. This is required for template substitution
1365 of `T' in the function parameter of `g' and template parameter
1366 of `h' in the above examples. Here ARGS corresponds to `int'. */
1373 {
1375 {
1378 else
1380 current_depth++;
1381 }
1383 }
1386 {
1388 tree friend_type;
1389 tree decl_type;
1390 tree friend_args_type;
1391 tree decl_args_type;
1393 /* Make sure that both DECL and FRIEND_DECL are templates or
1394 non-templates. */
1400 {
1401 /* If both are templates, check template parameter list. */
1402 tree friend_parms
1407 friend_parms))
1411 }
1412 else
1420 /* Check if return types match. */
1424 /* Check if function parameter types match, ignoring the
1425 `this' parameter. */
1434 }
1435 else
1436 {
1437 /* DECL is a TYPE_DECL */
1441 /* Make sure that both DECL and FRIEND_DECL are templates or
1442 non-templates. */
1443 is_template
1450 {
1451 tree friend_parms;
1452 /* If both are templates, check the name of the two
1453 TEMPLATE_DECL's first because is_friend didn't. */
1458 /* Now check template parameter list. */
1459 friend_parms
1462 return comp_template_parms
1464 friend_parms);
1465 }
1466 else
1469 }
1470 }
1472 }
1474 /* Register the specialization SPEC as a specialization of TMPL with
1475 the indicated ARGS. IS_FRIEND indicates whether the specialization
1476 is actually just a friend declaration. Returns SPEC, or an
1477 equivalent prior declaration, if available.
1479 We also store instantiations of field packs in the hash table, even
1480 though they are not themselves templates, to make lookup easier. */
1482 static tree
1484 hashval_t hash)
1485 {
1486 tree fn;
1488 spec_entry elt;
1496 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1497 register it; we want the corresponding TEMPLATE_DECL instead.
1498 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1499 the more obvious `uses_template_parms (spec)' to avoid problems
1500 with default function arguments. In particular, given
1501 something like this:
1503 template <class T> void f(T t1, T t = T())
1505 the default argument expression is not substituted for in an
1506 instantiation unless and until it is actually needed. */
1510 /* We don't put these specializations in the hash table, but we might
1511 want to give an error about a mismatch. */
1513 else
1514 {
1522 slot =
1526 else
1528 }
1530 /* We can sometimes try to re-register a specialization that we've
1531 already got. In particular, regenerate_decl_from_template calls
1532 duplicate_decls which will update the specialization list. But,
1533 we'll still get called again here anyhow. It's more convenient
1534 to simply allow this than to try to prevent it. */
1538 {
1540 {
1543 {
1545 fn);
1547 }
1548 else
1549 {
1550 tree clone;
1551 /* This situation should occur only if the first
1552 specialization is an implicit instantiation, the
1553 second is an explicit specialization, and the
1554 implicit instantiation has not yet been used. That
1555 situation can occur if we have implicitly
1556 instantiated a member function and then specialized
1557 it later.
1559 We can also wind up here if a friend declaration that
1560 looked like an instantiation turns out to be a
1561 specialization:
1563 template <class T> void foo(T);
1564 class S { friend void foo<>(int) };
1565 template <> void foo(int);
1567 We transform the existing DECL in place so that any
1568 pointers to it become pointers to the updated
1569 declaration.
1571 If there was a definition for the template, but not
1572 for the specialization, we want this to look as if
1573 there were no definition, and vice versa. */
1576 /* The call to duplicate_decls will have applied
1577 [temp.expl.spec]:
1579 An explicit specialization of a function template
1580 is inline only if it is explicitly declared to be,
1581 and independently of whether its function template
1582 is.
1584 to the primary function; now copy the inline bits to
1585 the various clones. */
1587 {
1594 }
1598 }
1599 }
1601 {
1604 /* We've already complained in duplicate_decls. */
1608 /* Dup decl failed, but this is a new definition. Set the
1609 line number so any errors match this new
1610 definition. */
1614 }
1615 }
1619 /* A specialization must be declared in the same namespace as the
1620 template it is specializing. */
1626 {
1635 /* If TMPL is a forward declaration of a template function, keep a list
1636 of all specializations in case we need to reassign them to a friend
1637 template later in tsubst_friend_function.
1639 Also keep a list of all variable template instantiations so that
1640 process_partial_specialization can check whether a later partial
1641 specialization would have used it. */
1644 }
1647 }
1649 /* Returns true iff two spec_entry nodes are equivalent. */
1653 bool
1655 {
1662 /* tmpl could be a FIELD_DECL for a capture pack. */
1666 {
1667 /* Partial specializations of a variable template can be distinguished by
1668 constraints. */
1672 }
1676 }
1678 /* Returns a hash for a template TMPL and template arguments ARGS. */
1680 static hashval_t
1682 {
1685 }
1687 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1688 ignoring SPEC. */
1690 hashval_t
1692 {
1694 }
1696 /* Recursively calculate a hash value for a template argument ARG, for use
1697 in the hash tables of template specializations. */
1699 hashval_t
1701 {
1721 {
1729 {
1734 }
1756 {
1760 {
1763 }
1765 }
1769 {
1772 }
1783 val = iterative_hash_template_arg
1795 val);
1797 val);
1806 /* A lambda can't appear in a template arg, but don't crash on
1807 erroneous input. */
1819 /* Now hash operands as usual. */
1824 }
1827 {
1830 {
1831 // We want an alias specialization that survived strip_typedefs
1832 // to hash differently from its TYPE_CANONICAL, to avoid hash
1833 // collisions that compare as different in template_args_equal.
1834 // These could be dependent specializations that strip_typedefs
1835 // left alone, or untouched specializations because
1836 // coerce_template_parms returns the unconverted template
1837 // arguments if it sees incomplete argument packs.
1840 }
1843 val);
1846 /* Otherwise just compare the types during lookup. */
1855 {
1860 }
1861 }
1864 }
1866 /* Unregister the specialization SPEC as a specialization of TMPL.
1867 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1868 if the SPEC was listed as a specialization of TMPL.
1870 Note that SPEC has been ggc_freed, so we can't look inside it. */
1872 bool
1874 {
1876 spec_entry elt;
1884 {
1889 }
1892 }
1894 /* Like register_specialization, but for local declarations. We are
1895 registering SPEC, an instantiation of TMPL. */
1897 void
1899 {
1902 }
1904 /* TYPE is a class type. Returns true if TYPE is an explicitly
1905 specialized class. */
1907 bool
1909 {
1913 }
1915 /* Print the list of functions at FNS, going through all the overloads
1916 for each element of the list. Alternatively, FNS can not be a
1917 TREE_LIST, in which case it will be printed together with all the
1918 overloads.
1920 MORE and *STR should respectively be FALSE and NULL when the function
1921 is called from the outside. They are used internally on recursive
1922 calls. print_candidates manages the two parameters and leaves NULL
1923 in *STR when it ends. */
1925 static void
1927 {
1931 else
1933 {
1939 {
1942 else
1945 }
1947 }
1948 }
1950 /* Print the list of candidate FNS in an error message. FNS can also
1951 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1953 void
1955 {
1959 }
1961 /* Get a (possibly) constrained template declaration for the
1962 purpose of ordering candidates. */
1963 static tree
1965 {
1971 }
1973 /* Among candidates having the same signature, return the
1974 most constrained or NULL_TREE if there is no best candidate.
1975 If the signatures of candidates vary (e.g., template
1976 specialization vs. member function), then there can be no
1977 most constrained.
1979 Note that we don't compare constraints on the functions
1980 themselves, but rather those of their templates. */
1981 static tree
1983 {
1984 // Try to find the best candidate in a first pass.
1987 {
1994 }
1996 // Verify that the champ is better than previous candidates.
2001 }
2004 }
2007 /* Returns the template (one of the functions given by TEMPLATE_ID)
2008 which can be specialized to match the indicated DECL with the
2009 explicit template args given in TEMPLATE_ID. The DECL may be
2010 NULL_TREE if none is available. In that case, the functions in
2011 TEMPLATE_ID are non-members.
2013 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2014 specialization of a member template.
2016 The TEMPLATE_COUNT is the number of references to qualifying
2017 template classes that appeared in the name of the function. See
2018 check_explicit_specialization for a more accurate description.
2020 TSK indicates what kind of template declaration (if any) is being
2021 declared. TSK_TEMPLATE indicates that the declaration given by
2022 DECL, though a FUNCTION_DECL, has template parameters, and is
2023 therefore a template function.
2025 The template args (those explicitly specified and those deduced)
2026 are output in a newly created vector *TARGS_OUT.
2028 If it is impossible to determine the result, an error message is
2029 issued. The error_mark_node is returned to indicate failure. */
2031 static tree
2033 tree decl,
2037 tmpl_spec_kind tsk)
2038 {
2039 tree fns;
2040 tree targs;
2041 tree explicit_targs;
2044 /* A TREE_LIST of templates of which DECL may be a specialization.
2045 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2046 corresponding TREE_PURPOSE is the set of template arguments that,
2047 when used to instantiate the template, would produce a function
2048 with the signature of DECL. */
2058 /* We shouldn't be specializing a member template of an
2059 unspecialized class template; we already gave an error in
2060 check_specialization_scope, now avoid crashing. */
2063 {
2066 }
2074 /* Check for baselinks. */
2079 {
2082 }
2084 {
2087 }
2089 /* Count the number of template headers specified for this
2090 specialization. */
2100 {
2103 tf_warning_or_error,
2107 }
2109 {
2113 {
2114 tree decl_arg_types;
2115 tree fn_arg_types;
2116 tree insttype;
2118 /* In case of explicit specialization, we need to check if
2119 the number of template headers appearing in the specialization
2120 is correct. This is usually done in check_explicit_specialization,
2121 but the check done there cannot be exhaustive when specializing
2122 member functions. Consider the following code:
2124 template <> void A<int>::f(int);
2125 template <> template <> void A<int>::f(int);
2127 Assuming that A<int> is not itself an explicit specialization
2128 already, the first line specializes "f" which is a non-template
2129 member function, whilst the second line specializes "f" which
2130 is a template member function. So both lines are syntactically
2131 correct, and check_explicit_specialization does not reject
2132 them.
2134 Here, we can do better, as we are matching the specialization
2135 against the declarations. We count the number of template
2136 headers, and we check if they match TEMPLATE_COUNT + 1
2137 (TEMPLATE_COUNT is the number of qualifying template classes,
2138 plus there must be another header for the member template
2139 itself).
2141 Notice that if header_count is zero, this is not a
2142 specialization but rather a template instantiation, so there
2143 is no check we can perform here. */
2147 /* Check that the number of template arguments at the
2148 innermost level for DECL is the same as for FN. */
2156 /* DECL might be a specialization of FN. */
2160 /* For a non-static member function, we need to make sure
2161 that the const qualification is the same. Since
2162 get_bindings does not try to merge the "this" parameter,
2163 we must do the comparison explicitly. */
2169 /* Skip the "this" parameter and, for constructors of
2170 classes with virtual bases, the VTT parameter. A
2171 full specialization of a constructor will have a VTT
2172 parameter, but a template never will. */
2173 decl_arg_types
2175 fn_arg_types
2178 /* Function templates cannot be specializations; there are
2179 no partial specializations of functions. Therefore, if
2180 the type of DECL does not match FN, there is no
2181 match.
2183 Note that it should never be the case that we have both
2184 candidates added here, and for regular member functions
2185 below. */
2187 {
2191 }
2193 /* See whether this function might be a specialization of this
2194 template. Suppress access control because we might be trying
2195 to make this specialization a friend, and we have already done
2196 access control for the declaration of the specialization. */
2202 /* We cannot deduce template arguments that when used to
2203 specialize TMPL will produce DECL. */
2206 /* Remove, from the set of candidates, all those functions
2207 whose constraints are not satisfied. */
2211 // Then, try to form the new function type.
2215 fn_arg_types
2220 /* Save this template, and the arguments deduced. */
2222 }
2224 /* FN is an ordinary member function, and we need a
2225 specialization of a member template. */
2226 ;
2228 /* We can get IDENTIFIER_NODEs here in certain erroneous
2229 cases. */
2230 ;
2232 /* This is just an ordinary non-member function. Nothing can
2233 be a specialization of that. */
2234 ;
2236 /* Cannot specialize functions that are created implicitly. */
2237 ;
2238 else
2239 {
2240 tree decl_arg_types;
2242 /* This is an ordinary member function. However, since
2243 we're here, we can assume its enclosing class is a
2244 template class. For example,
2246 template <typename T> struct S { void f(); };
2247 template <> void S<int>::f() {}
2249 Here, S<int>::f is a non-template, but S<int> is a
2250 template class. If FN has the same type as DECL, we
2251 might be in business. */
2254 /* Its enclosing class is an explicit specialization
2255 of a template class. This is not a candidate. */
2260 /* The return types differ. */
2263 /* Adjust the type of DECL in case FN is a static member. */
2270 decl_arg_types))
2273 // If the deduced arguments do not satisfy the constraints,
2274 // this is not a candidate.
2278 // Add the candidate.
2280 }
2281 }
2284 {
2285 /* We have:
2287 [temp.expl.spec]
2289 It is possible for a specialization with a given function
2290 signature to be instantiated from more than one function
2291 template. In such cases, explicit specification of the
2292 template arguments must be used to uniquely identify the
2293 function template specialization being specialized.
2295 Note that here, there's no suggestion that we're supposed to
2296 determine which of the candidate templates is most
2297 specialized. However, we, also have:
2299 [temp.func.order]
2301 Partial ordering of overloaded function template
2302 declarations is used in the following contexts to select
2303 the function template to which a function template
2304 specialization refers:
2306 -- when an explicit specialization refers to a function
2307 template.
2309 So, we do use the partial ordering rules, at least for now.
2310 This extension can only serve to make invalid programs valid,
2311 so it's safe. And, there is strong anecdotal evidence that
2312 the committee intended the partial ordering rules to apply;
2313 the EDG front end has that behavior, and John Spicer claims
2314 that the committee simply forgot to delete the wording in
2315 [temp.expl.spec]. */
2318 {
2321 }
2322 }
2324 // Concepts allows multiple declarations of member functions
2325 // with the same signature. Like above, we need to rely on
2326 // on the partial ordering of those candidates to determine which
2327 // is the best.
2329 {
2331 {
2334 }
2335 }
2338 {
2345 else
2348 }
2352 {
2358 }
2360 /* We have one, and exactly one, match. */
2362 {
2366 // Propagate the candidate's constraints to the declaration.
2369 /* DECL is a re-declaration or partial instantiation of a template
2370 function. */
2373 /* It was a specialization of an ordinary member function in a
2374 template class. */
2376 }
2378 /* It was a specialization of a template. */
2381 {
2386 }
2387 else
2390 }
2392 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2393 but with the default argument values filled in from those in the
2394 TMPL_TYPES. */
2396 static tree
2398 tree tmpl_types)
2399 {
2400 tree new_spec_types;
2408 /* Substitute into the rest of the list. */
2409 new_spec_types =
2413 /* Add the default argument for this parameter. */
2416 new_spec_types);
2417 }
2419 /* DECL is an explicit specialization. Replicate default arguments
2420 from the template it specializes. (That way, code like:
2422 template <class T> void f(T = 3);
2423 template <> void f(double);
2424 void g () { f (); }
2426 works, as required.) An alternative approach would be to look up
2427 the correct default arguments at the call-site, but this approach
2428 is consistent with how implicit instantiations are handled. */
2430 static void
2432 {
2433 tree tmpl;
2434 tree spec_types;
2435 tree tmpl_types;
2436 tree new_spec_types;
2437 tree old_type;
2438 tree new_type;
2439 tree t;
2444 /* See if there's anything we need to do. */
2457 {
2458 /* Remove the this pointer, but remember the object's type for
2459 CV quals. */
2465 {
2466 /* DECL may contain more parameters than TMPL due to the extra
2467 in-charge parameter in constructors and destructors. */
2470 }
2472 {
2475 }
2476 }
2478 /* Compute the merged default arguments. */
2479 new_spec_types =
2482 /* Compute the new FUNCTION_TYPE. */
2484 {
2488 new_spec_types);
2491 /* Put the in-charge parameter back. */
2494 new_spec_types);
2498 new_spec_types);
2499 }
2500 else
2502 new_spec_types);
2512 }
2514 /* Return the number of template headers we expect to see for a definition
2515 or specialization of CTYPE or one of its non-template members. */
2517 int
2519 {
2523 {
2524 /* You're supposed to have one `template <...>' for every
2525 template class, but you don't need one for a full
2526 specialization. For example:
2528 template <class T> struct S{};
2529 template <> struct S<int> { void f(); };
2530 void S<int>::f () {}
2532 is correct; there shouldn't be a `template <>' for the
2533 definition of `S<int>::f'. */
2535 /* If CTYPE does not have template information of any
2536 kind, then it is not a template, nor is it nested
2537 within a template. */
2545 }
2548 }
2550 /* Do a simple sanity check on the template headers that precede the
2551 variable declaration DECL. */
2553 void
2555 {
2560 {
2563 "variable templates only available with "
2566 // Namespace-scope variable templates should have a template header.
2568 }
2570 {
2572 "too many template headers for %qD "
2578 "members of an explicitly specialized class are defined "
2580 }
2581 }
2583 /* An explicit specialization whose declarator-id or class-head-name is not
2584 qualified shall be declared in the nearest enclosing namespace of the
2585 template, or, if the namespace is inline (7.3.1), any namespace from its
2586 enclosing namespace set.
2588 If the name declared in the explicit instantiation is an unqualified name,
2589 the explicit instantiation shall appear in the namespace where its template
2590 is declared or, if that namespace is inline (7.3.1), any namespace from its
2591 enclosing namespace set. */
2593 void
2595 {
2600 {
2606 /* This was allowed in C++98, so only pedwarn. */
2608 "outside its namespace must use a nested-name-"
2610 }
2611 }
2613 /* Check to see if the function just declared, as indicated in
2614 DECLARATOR, and in DECL, is a specialization of a function
2615 template. We may also discover that the declaration is an explicit
2616 instantiation at this point.
2618 Returns DECL, or an equivalent declaration that should be used
2619 instead if all goes well. Issues an error message if something is
2620 amiss. Returns error_mark_node if the error is not easily
2621 recoverable.
2623 FLAGS is a bitmask consisting of the following flags:
2625 2: The function has a definition.
2626 4: The function is a friend.
2628 The TEMPLATE_COUNT is the number of references to qualifying
2629 template classes that appeared in the name of the function. For
2630 example, in
2632 template <class T> struct S { void f(); };
2633 void S<int>::f();
2635 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2636 classes are not counted in the TEMPLATE_COUNT, so that in
2638 template <class T> struct S {};
2639 template <> struct S<int> { void f(); }
2640 template <> void S<int>::f();
2642 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2643 invalid; there should be no template <>.)
2645 If the function is a specialization, it is marked as such via
2646 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2647 is set up correctly, and it is added to the list of specializations
2648 for that template. */
2650 tree
2652 tree decl,
2655 {
2664 tmpl_spec_kind tsk;
2667 {
2670 else
2672 }
2673 else
2677 {
2680 {
2683 }
2685 {
2687 /* This could be something like:
2689 template <class T> void f(T);
2690 class S { friend void f<>(int); } */
2692 else
2693 {
2694 /* This case handles bogus declarations like template <>
2695 template <class T> void f<int>(); */
2698 declarator);
2700 }
2701 }
2705 /* The error has already been reported in
2706 check_specialization_scope. */
2712 /* Fall through. */
2725 decl);
2728 else
2732 /* Fall through. */
2738 /* In cases like template<> constexpr bool v = true;
2739 We'll give an error in check_template_variable. */
2745 else
2751 {
2752 /* This case handles bogus declarations like template <>
2753 template <class T> void f<int>(); */
2757 declarator);
2759 {
2760 /* Partial specialization of variable template. */
2764 }
2768 else
2772 ok:;
2773 }
2776 /* This is a specialization of a member template, without
2777 specialization the containing class. Something like:
2779 template <class T> struct S {
2780 template <class U> void f (U);
2781 };
2782 template <> template <class U> void S<int>::f(U) {}
2784 That's a specialization -- but of the entire template. */
2790 }
2793 /* This doesn't apply to variable templates. */
2796 {
2800 {
2804 }
2805 }
2808 {
2813 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2815 {
2816 tree fns;
2821 else
2822 {
2823 /* If there is no class context, the explicit instantiation
2824 must be at namespace scope. */
2827 /* Find the namespace binding, using the declaration
2828 context. */
2832 /* If lookup fails, look for a friend declaration so we can
2833 give a better diagnostic. */
2839 {
2842 }
2843 }
2846 }
2852 {
2854 /* A specialization in class scope. This is invalid,
2855 but the error will already have been flagged by
2856 check_specialization_scope. */
2858 else
2859 {
2860 /* It's not valid to write an explicit instantiation in
2861 class scope, e.g.:
2863 class C { template void f(); }
2865 This case is caught by the parser. However, on
2866 something like:
2868 template class C { void f(); };
2870 (which is invalid) we can get here. The error will be
2871 issued later. */
2872 ;
2873 }
2876 }
2879 {
2880 // We'll match variable templates in start_decl.
2884 /* Find the list of functions in ctype that have the same
2885 name as the declared function. */
2889 {
2893 {
2894 /* From [temp.expl.spec]:
2896 If such an explicit specialization for the member
2897 of a class template names an implicitly-declared
2898 special member function (clause _special_), the
2899 program is ill-formed.
2901 Similar language is found in [temp.explicit]. */
2904 }
2907 }
2909 /* For a type-conversion operator, We might be looking for
2910 `operator int' which will be a specialization of
2911 `operator T'. Grab all the conversion operators, and
2912 then select from them. */
2917 {
2920 }
2921 else
2923 }
2925 /* Figure out what exactly is being specialized at this point.
2926 Note that for an explicit instantiation, even one for a
2927 member function, we cannot tell a priori whether the
2928 instantiation is for a member template, or just a member
2929 function of a template class. Even if a member template is
2930 being instantiated, the member template arguments may be
2931 elided if they can be deduced from the rest of the
2932 declaration. */
2935 member_specialization,
2936 template_count,
2937 tsk);
2940 /* We couldn't figure out what this declaration was
2941 specializing. */
2943 else
2944 {
2947 {
2949 "friend declaration %qD is not visible to "
2953 }
2961 {
2962 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2963 is done by do_decl_instantiation later. */
2969 {
2970 /* If TMPL is not the most general template (for
2971 example, if TMPL is a friend template that is
2972 injected into namespace scope), then there will
2973 be too many levels of TARGS. Remove some of them
2974 here. */
2976 tree new_targs;
2983 }
2986 }
2988 /* If we thought that the DECL was a member function, but it
2989 turns out to be specializing a static member function,
2990 make DECL a static member function as well. */
2996 /* If this is a specialization of a member template of a
2997 template class, we want to return the TEMPLATE_DECL, not
2998 the specialization of it. */
3000 {
3005 {
3006 tree parm;
3010 /* We want to use the argument list specified in the
3011 definition, not in the original declaration. */
3016 }
3019 }
3021 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3027 /* Inherit default function arguments from the template
3028 DECL is specializing. */
3032 /* This specialization has the same protection as the
3033 template it specializes. */
3037 /* 7.1.1-1 [dcl.stc]
3039 A storage-class-specifier shall not be specified in an
3040 explicit specialization...
3042 The parser rejects these, so unless action is taken here,
3043 explicit function specializations will always appear with
3044 global linkage.
3046 The action recommended by the C++ CWG in response to C++
3047 defect report 605 is to make the storage class and linkage
3048 of the explicit specialization match the templated function:
3050 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3051 */
3053 {
3057 /* A concept cannot be specialized. */
3059 {
3061 gen_tmpl);
3063 }
3065 /* This specialization has the same linkage and visibility as
3066 the function template it specializes. */
3069 {
3072 }
3075 {
3078 }
3079 }
3081 /* If DECL is a friend declaration, declared using an
3082 unqualified name, the namespace associated with DECL may
3083 have been set incorrectly. For example, in:
3085 template <typename T> void f(T);
3086 namespace N {
3087 struct S { friend void f<int>(int); }
3088 }
3090 we will have set the DECL_CONTEXT for the friend
3091 declaration to N, rather than to the global namespace. */
3096 /* This is not really a declaration of a specialization.
3097 It's just the name of an instantiation. But, it's not
3098 a request for an instantiation, either. */
3101 /* A specialization is not necessarily COMDAT. */
3107 /* If this is a full specialization, register it so that we can find
3108 it again. Partial specializations will be registered in
3109 process_partial_specialization. */
3114 /* A 'structor should already have clones. */
3120 }
3121 }
3124 }
3126 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3127 parameters. These are represented in the same format used for
3128 DECL_TEMPLATE_PARMS. */
3130 int
3132 {
3133 const_tree p1;
3134 const_tree p2;
3142 {
3154 {
3158 /* If either of the template parameters are invalid, assume
3159 they match for the sake of error recovery. */
3172 }
3173 }
3176 /* One set of parameters has more parameters lists than the
3177 other. */
3181 }
3183 /* Determine whether PARM is a parameter pack. */
3185 bool
3187 {
3188 /* Determine if we have a non-type template parameter pack. */
3195 /* If this is a list of template parameters, we could get a
3196 TYPE_DECL or a TEMPLATE_DECL. */
3200 /* Otherwise it must be a type template parameter. */
3204 }
3206 /* Determine if T is a function parameter pack. */
3208 bool
3210 {
3214 }
3216 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3217 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3219 tree
3221 {
3228 }
3230 /* Return true iff the function parameter PARAM_DECL was expanded
3231 from the function parameter pack PACK. */
3233 bool
3235 {
3240 /* The parameter pack and its pack arguments have the same
3241 DECL_PARM_INDEX. */
3243 }
3245 /* Determine whether ARGS describes a variadic template args list,
3246 i.e., one that is terminated by a template argument pack. */
3248 static bool
3250 {
3252 tree last_parm;
3266 }
3268 /* Generate a new name for the parameter pack name NAME (an
3269 IDENTIFIER_NODE) that incorporates its */
3271 static tree
3273 {
3274 /* Munge the name to include the parameter index. */
3275 #define NUMBUF_LEN 128
3289 }
3291 /* Return true if T is a primary function, class or alias template
3292 specialization, not including the template pattern. */
3294 bool
3296 {
3312 }
3314 /* Return true if PARM is a template template parameter. */
3316 bool
3318 {
3320 }
3322 /* Return true iff PARM is a DECL representing a type template
3323 parameter. */
3325 bool
3327 {
3332 }
3334 /* Return the template parameters of T if T is a
3335 primary template instantiation, NULL otherwise. */
3337 tree
3339 {
3344 parms = INNERMOST_TEMPLATE_PARMS
3348 }
3350 /* Return the template parameters of the LEVELth level from the full list
3351 of template parameters PARMS. */
3353 tree
3355 {
3356 tree p;
3367 }
3369 /* Returns the template arguments of T if T is a template instantiation,
3370 NULL otherwise. */
3372 tree
3374 {
3382 }
3384 /* Return the argument pack elements of T if T is a template argument pack,
3385 NULL otherwise. */
3387 tree
3389 {
3395 }
3397 /* True iff FN is a function representing a built-in variadic parameter
3398 pack. */
3400 bool
3402 {
3412 }
3414 /* True iff CALL is a call to a function representing a built-in variadic
3415 parameter pack. */
3417 static bool
3419 {
3423 }
3425 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3427 static tree
3429 tree in_decl)
3430 {
3436 {
3438 {
3441 }
3446 }
3447 else
3448 {
3452 /* Calculate the largest value of len that won't make the size of the vec
3453 overflow an int. The compiler will exceed resource limits long before
3454 this, but it seems a decent place to diagnose. */
3458 {
3463 }
3471 }
3472 }
3474 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3475 CALL. */
3477 static tree
3479 tree in_decl)
3480 {
3490 }
3492 /* Structure used to track the progress of find_parameter_packs_r. */
3493 struct find_parameter_pack_data
3494 {
3495 /* TREE_LIST that will contain all of the parameter packs found by
3496 the traversal. */
3499 /* Set of AST nodes that have been visited by the traversal. */
3502 /* True iff we're making a type pack expansion. */
3504 };
3506 /* Identifies all of the argument packs that occur in a template
3507 argument and appends them to the TREE_LIST inside DATA, which is a
3508 find_parameter_pack_data structure. This is a subroutine of
3509 make_pack_expansion and uses_parameter_packs. */
3510 static tree
3512 {
3518 /* Handle type aliases/typedefs. */
3520 {
3527 }
3529 /* Identify whether this is a parameter pack or not. */
3531 {
3539 /* FALLTHRU */
3541 /* If the placeholder appears in the decl-specifier-seq of a function
3542 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3543 is a pack expansion, the invented template parameter is a template
3544 parameter pack. */
3554 {
3555 /* We don't want to walk into the type of a PARM_DECL,
3556 because we don't want to see the type parameter pack. */
3559 }
3562 /* Look through a lambda capture proxy to the field pack. */
3565 {
3571 }
3573 {
3575 find_parameter_packs_r,
3578 }
3590 /* Not a parameter pack. */
3592 }
3595 {
3596 /* Add this parameter pack to the list. */
3598 }
3604 /* This switch statement will return immediately if we don't find a
3605 parameter pack. */
3607 {
3612 /* Check the template itself. */
3615 /* Check the template arguments. */
3629 /* Ignore the declaration of a capture proxy for a parameter pack. */
3637 /* Fall through. */
3682 {
3688 }
3691 {
3692 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3693 type_pack_expansion_p to false so that any placeholders
3694 within the expression don't get marked as parameter packs. */
3702 }
3706 }
3709 }
3711 /* Determines if the expression or type T uses any parameter packs. */
3712 bool
3714 {
3723 }
3725 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3726 representation a base-class initializer into a parameter pack
3727 expansion. If all goes well, the resulting node will be an
3728 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3729 respectively. */
3730 tree
3732 {
3733 tree result;
3742 {
3743 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3744 class initializer. In this case, the TREE_PURPOSE will be a
3745 _TYPE node (representing the base class expansion we're
3746 initializing) and the TREE_VALUE will be a TREE_LIST
3747 containing the initialization arguments.
3749 The resulting expansion looks somewhat different from most
3750 expansions. Rather than returning just one _EXPANSION, we
3751 return a TREE_LIST whose TREE_PURPOSE is a
3752 TYPE_PACK_EXPANSION containing the bases that will be
3753 initialized. The TREE_VALUE will be identical to the
3754 original TREE_VALUE, which is a list of arguments that will
3755 be passed to each base. We do not introduce any new pack
3756 expansion nodes into the TREE_VALUE (although it is possible
3757 that some already exist), because the TREE_PURPOSE and
3758 TREE_VALUE all need to be expanded together with the same
3759 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3760 resulting TREE_PURPOSE will mention the parameter packs in
3761 both the bases and the arguments to the bases. */
3762 tree purpose;
3763 tree value;
3766 /* Determine which parameter packs will be used by the base
3767 class expansion. */
3776 {
3779 arg);
3782 }
3785 {
3786 /* Collect the sets of parameter packs used in each of the
3787 initialization arguments. */
3789 {
3790 /* Determine which parameter packs will be expanded in this
3791 argument. */
3794 }
3795 }
3799 /* Create the pack expansion type for the base type. */
3805 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3806 they will rarely be compared to anything. */
3810 }
3815 /* Build the PACK_EXPANSION_* node. */
3816 result = for_types
3821 {
3822 /* Propagate type and const-expression information. */
3825 /* Mark this read now, since the expansion might be length 0. */
3827 }
3828 else
3829 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3830 they will rarely be compared to anything. */
3833 /* Determine which parameter packs will be expanded. */
3840 /* Make sure we found some parameter packs. */
3842 {
3844 {
3847 else
3849 }
3851 }
3857 }
3859 /* Checks T for any "bare" parameter packs, which have not yet been
3860 expanded, and issues an error if any are found. This operation can
3861 only be done on full expressions or types (e.g., an expression
3862 statement, "if" condition, etc.), because we could have expressions like:
3864 foo(f(g(h(args)))...)
3866 where "args" is a parameter pack. check_for_bare_parameter_packs
3867 should not be called for the subexpressions args, h(args),
3868 g(h(args)), or f(g(h(args))), because we would produce erroneous
3869 error messages.
3871 Returns TRUE and emits an error if there were bare parameter packs,
3872 returns FALSE otherwise. */
3873 bool
3875 {
3882 /* A lambda might use a parameter pack from the containing context. */
3896 {
3900 {
3911 else
3916 else
3920 }
3923 }
3926 }
3928 /* Expand any parameter packs that occur in the template arguments in
3929 ARGS. */
3930 tree
3932 {
3941 /* First, determine if we need to expand anything, and the number of
3942 slots we'll need. */
3944 {
3949 {
3953 else
3955 }
3956 else
3957 {
3959 num_result_args++;
3960 }
3961 }
3963 /* If no expansion is necessary, we're done. */
3967 /* Expand arguments. */
3970 non_default_args_count =
3973 {
3976 {
3983 }
3984 else
3985 {
3988 }
3989 }
3993 }
3995 /* Checks if DECL shadows a template parameter.
3997 [temp.local]: A template-parameter shall not be redeclared within its
3998 scope (including nested scopes).
4000 Emits an error and returns TRUE if the DECL shadows a parameter,
4001 returns FALSE otherwise. */
4003 bool
4005 {
4006 tree olddecl;
4008 /* If we're not in a template, we can't possibly shadow a template
4009 parameter. */
4013 /* Figure out what we're shadowing. */
4017 /* If there's no previous binding for this name, we're not shadowing
4018 anything, let alone a template parameter. */
4022 /* If we're not shadowing a template parameter, we're done. Note
4023 that OLDDECL might be an OVERLOAD (or perhaps even an
4024 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4025 node. */
4029 /* We check for decl != olddecl to avoid bogus errors for using a
4030 name inside a class. We check TPFI to avoid duplicate errors for
4031 inline member templates. */
4037 /* Don't complain about the injected class name, as we've already
4038 complained about the class itself. */
4045 else
4050 }
4052 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4053 ORIG_LEVEL, DECL, and TYPE. */
4055 static tree
4059 tree decl,
4060 tree type)
4061 {
4072 }
4074 /* Find the canonical type parameter for the given template type
4075 parameter. Returns the canonical type parameter, which may be TYPE
4076 if no such parameter existed. */
4078 static tree
4080 {
4081 tree list;
4095 else
4096 {
4100 }
4101 }
4103 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4104 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4105 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4106 new one is created. */
4108 static tree
4110 tsubst_flags_t complain)
4111 {
4116 {
4135 /* Template template parameters need this. */
4137 {
4144 }
4145 }
4148 }
4150 /* Process information from new template parameter PARM and append it
4151 to the LIST being built. This new parameter is a non-type
4152 parameter iff IS_NON_TYPE is true. This new parameter is a
4153 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4154 is in PARM_LOC. */
4156 tree
4159 {
4168 {
4172 {
4176 else
4178 }
4181 }
4184 {
4190 {
4191 /* [temp.param]
4193 The top-level cv-qualifiers on the template-parameter are
4194 ignored when determining its type. */
4199 && !is_parameter_pack
4200 /* If we're in a nested template parameter list, the template
4201 template parameter could be a parameter pack. */
4203 {
4204 /* This template parameter is not a parameter pack, but it
4205 should be. Complain about "bare" parameter packs. */
4208 /* Recover by calling this a parameter pack. */
4210 }
4211 }
4213 /* A template parameter is not modifiable. */
4222 processing_template_decl,
4227 }
4228 else
4229 {
4230 tree t;
4234 {
4236 /* This is for distinguishing between real templates and template
4237 template parameters */
4241 }
4242 else
4243 {
4245 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4248 }
4255 processing_template_decl,
4259 }
4263 /* Build requirements for the type/template parameter.
4264 This must be done after SET_DECL_TEMPLATE_PARM_P or
4265 process_template_parm could fail. */
4270 /* Build the parameter node linking the parameter declaration,
4271 its default argument (if any), and its constraints (if any). */
4276 }
4278 /* The end of a template parameter list has been reached. Process the
4279 tree list into a parameter vector, converting each parameter into a more
4280 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4281 as PARM_DECLs. */
4283 tree
4285 {
4290 /* Pop the dummy parameter level and add the real one. */
4293 current_template_parms
4298 {
4302 }
4307 }
4309 // Explicitly indicate the end of the template parameter list. We assume
4310 // that the current template parameters have been constructed and/or
4311 // managed explicitly, as when creating new template template parameters
4312 // from a shorthand constraint.
4313 void
4315 {
4317 }
4319 /* end_template_decl is called after a template declaration is seen. */
4321 void
4323 {
4329 /* This matches the pushlevel in begin_template_parm_list. */
4334 }
4336 /* Takes a TREE_LIST representing a template parameter and convert it
4337 into an argument suitable to be passed to the type substitution
4338 functions. Note that If the TREE_LIST contains an error_mark
4339 node, the returned argument is error_mark_node. */
4341 tree
4343 {
4356 {
4360 {
4361 /* Turn this argument into a TYPE_ARGUMENT_PACK
4362 with a single element, which expands T. */
4371 }
4372 }
4373 else
4374 {
4378 {
4379 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4380 with a single element, which expands T. */
4390 }
4391 else
4393 }
4395 }
4397 /* Given a single level of template parameters (a TREE_VEC), return it
4398 as a set of template arguments. */
4400 static tree
4402 {
4412 }
4414 /* Given a set of template parameters, return them as a set of template
4415 arguments. The template parameters are represented as a TREE_VEC, in
4416 the form documented in cp-tree.h for template arguments. */
4418 static tree
4420 {
4421 tree header;
4426 /* If there is only one level of template parameters, we do not
4427 create a TREE_VEC of TREE_VECs. Instead, we return a single
4428 TREE_VEC containing the arguments. */
4433 {
4438 else
4440 }
4443 }
4445 /* Within the declaration of a template, return the currently active
4446 template parameters as an argument TREE_VEC. */
4448 static tree
4450 {
4452 }
4454 /* Update the declared TYPE by doing any lookups which were thought to be
4455 dependent, but are not now that we know the SCOPE of the declarator. */
4457 tree
4459 {
4470 /* Don't bother building up the args in this case. */
4472 {
4473 /* tsubst in the args corresponding to the template parameters,
4474 including auto if present. Most things will be unchanged, but
4475 make_typename_type and tsubst_qualified_id will resolve
4476 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4479 tree pushed;
4481 {
4485 }
4490 }
4496 {
4499 else
4501 }
4503 }
4505 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4506 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4507 the new template is a member template. */
4509 tree
4511 {
4519 }
4521 struct template_parm_data
4522 {
4523 /* The level of the template parameters we are currently
4524 processing. */
4527 /* The index of the specialization argument we are currently
4528 processing. */
4531 /* An array whose size is the number of template parameters. The
4532 elements are nonzero if the parameter has been used in any one
4533 of the arguments processed so far. */
4536 /* An array whose size is the number of template arguments. The
4537 elements are nonzero if the argument makes use of template
4538 parameters of this level. */
4540 };
4542 /* Subroutine of push_template_decl used to see if each template
4543 parameter in a partial specialization is used in the explicit
4544 argument list. If T is of the LEVEL given in DATA (which is
4545 treated as a template_parm_data*), then DATA->PARMS is marked
4546 appropriately. */
4548 static int
4550 {
4558 {
4561 }
4563 /* In C++17 the type of a non-type argument is a deduced context. */
4568 data,
4569 NULL,
4572 /* Return zero so that for_each_template_parm will continue the
4573 traversal of the tree; we want to mark *every* template parm. */
4575 }
4577 /* Process the partial specialization DECL. */
4579 static tree
4581 {
4588 tree inner_parms;
4589 tree inst;
4599 /* A concept cannot be specialized. */
4601 {
4604 }
4609 /* We check that each of the template parameters given in the
4610 partial specialization is used in the argument list to the
4611 specialization. For example:
4613 template <class T> struct S;
4614 template <class T> struct S<T*>;
4616 The second declaration is OK because `T*' uses the template
4617 parameter T, whereas
4619 template <class T> struct S<int>;
4621 is no good. Even trickier is:
4623 template <class T>
4624 struct S1
4625 {
4626 template <class U>
4627 struct S2;
4628 template <class U>
4629 struct S2<T>;
4630 };
4632 The S2<T> declaration is actually invalid; it is a
4633 full-specialization. Of course,
4635 template <class U>
4636 struct S2<T (*)(U)>;
4638 or some such would have been OK. */
4646 {
4651 NULL,
4653 }
4656 {
4657 /* One of the template parms was not used in a deduced context in the
4658 specialization. */
4660 {
4664 }
4668 }
4673 /* [temp.class.spec]
4675 The argument list of the specialization shall not be identical to
4676 the implicit argument list of the primary template. */
4677 tree main_args
4680 && (!flag_concepts
4683 {
4687 else
4691 }
4693 /* A partial specialization that replaces multiple parameters of the
4694 primary template with a pack expansion is less specialized for those
4695 parameters. */
4697 {
4699 "primary template because it replaces multiple parameters "
4702 /* Avoid crash in process_partial_specialization. */
4704 }
4706 /* If we aren't in a dependent class, we can actually try deduction. */
4708 /* FIXME we should be able to handle a partial specialization of a
4709 partial instantiation, but currently we can't (c++/41727). */
4712 {
4716 maintmpl);
4717 }
4719 /* [temp.class.spec]
4721 A partially specialized non-type argument expression shall not
4722 involve template parameters of the partial specialization except
4723 when the argument expression is a simple identifier.
4725 The type of a template parameter corresponding to a specialized
4726 non-type argument shall not be dependent on a parameter of the
4727 specialization.
4729 Also, we verify that pack expansions only occur at the
4730 end of the argument list. */
4734 {
4741 {
4742 /* Extract the arguments from the argument pack. We'll be
4743 iterating over these in the following loop. */
4746 }
4749 {
4751 /* Get the Jth argument in the parameter pack. */
4755 {
4756 /* Pack expansions must come at the end of the
4757 argument list. */
4760 {
4764 else
4767 }
4768 }
4771 /* We only care about the pattern. */
4777 /* This next two lines are the `argument expression is not just a
4778 simple identifier' condition and also the `specialized
4779 non-type argument' bit. */
4783 {
4787 arg);
4788 else
4789 {
4790 /* Look at the corresponding template parameter,
4791 marking which template parameters its type depends
4792 upon. */
4796 {
4797 /* We haven't yet initialized TPD2. Do so now. */
4799 /* The number of parameters here is the number in the
4800 main template, which, as checked in the assertion
4801 above, is NARGS. */
4805 }
4807 /* Mark the template parameters. But this time, we're
4808 looking for the template parameters of the main
4809 template, not in the specialization. */
4816 NULL,
4820 {
4821 /* The type depended on some template parameters.
4822 If they are fully specialized in the
4823 specialization, that's OK. */
4832 "type %qT of template argument %qE depends "
4834 "type %qT of template argument %qE depends "
4836 type,
4837 arg);
4838 }
4839 }
4840 }
4841 }
4842 }
4844 /* We should only get here once. */
4848 // Build the template decl.
4857 /* Give template template parms a DECL_CONTEXT of the template
4858 for which they are a parameter. */
4860 {
4864 }
4867 /* We didn't register this in check_explicit_specialization so we could
4868 wait until the constraints were set. */
4870 else
4880 {
4886 {
4894 "declaration of %qD ambiguates earlier template "
4898 "partial specialization of %qD after instantiation "
4900 }
4901 }
4904 }
4906 /* PARM is a template parameter of some form; return the corresponding
4907 TEMPLATE_PARM_INDEX. */
4909 static tree
4911 {
4924 }
4926 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4927 parameter packs used by the template parameter PARM. */
4929 static void
4931 {
4932 /* A type parm can't refer to another parm. */
4936 {
4940 }
4947 }
4949 /* PARM is a template parameter pack. Return any parameter packs used in
4950 its type or the type of any of its template parameters. If there are
4951 any such packs, it will be instantiated into a fixed template parameter
4952 list by partial instantiation rather than be fully deduced. */
4954 tree
4956 {
4957 /* This can only be true in a member template. */
4960 /* This can only be true for a parameter pack. */
4963 /* A type parm can't refer to another parm. */
4977 }
4979 /* Check that a template declaration's use of default arguments and
4980 parameter packs is not invalid. Here, PARMS are the template
4981 parameters. IS_PRIMARY is true if DECL is the thing declared by
4982 a primary template. IS_PARTIAL is true if DECL is a partial
4983 specialization.
4985 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
4986 function template declaration or a friend class template
4987 declaration. In the function case, 1 indicates a declaration, 2
4988 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4989 emitted for extraneous default arguments.
4991 Returns TRUE if there were no errors found, FALSE otherwise. */
4993 bool
4996 {
4999 tree parm_level;
5002 /* [temp.param]
5004 A default template-argument shall not be specified in a
5005 function template declaration or a function template definition, nor
5006 in the template-parameter-list of the definition of a member of a
5007 class template. */
5011 /* You can't have a function template declaration in a local
5012 scope, nor you can you define a member of a class template in a
5013 local scope. */
5021 /* A lambda doesn't have an explicit declaration; don't complain
5022 about the parms of the enclosing class. */
5029 /* If this is either a friend defined in the scope of the class
5030 or a member function. */
5036 /* And, if it was a member function, it really was defined in
5037 the scope of the class. */
5040 /* We already checked these parameters when the template was
5041 declared, so there's no need to do it again now. This function
5042 was defined in class scope, but we're processing its body now
5043 that the class is complete. */
5046 /* Core issue 226 (C++0x only): the following only applies to class
5047 templates. */
5050 {
5051 /* [temp.param]
5053 If a template-parameter has a default template-argument, all
5054 subsequent template-parameters shall have a default
5055 template-argument supplied. */
5057 {
5064 {
5074 {
5076 /* For better subsequent error-recovery, we indicate that
5077 there should have been a default argument. */
5080 }
5082 && !is_friend_decl
5083 /* Don't complain about an enclosing partial
5084 specialization. */
5089 /* A fixed parameter pack will be partially
5090 instantiated into a fixed length list. */
5092 {
5093 /* A primary class template can only have one
5094 parameter pack, at the end of the template
5095 parameter list. */
5103 }
5104 }
5105 }
5106 }
5109 || is_partial
5110 || !is_primary
5112 /* For an ordinary class template, default template arguments are
5113 allowed at the innermost level, e.g.:
5114 template <class T = int>
5115 struct S {};
5116 but, in a partial specialization, they're not allowed even
5117 there, as we have in [temp.class.spec]:
5119 The template parameter list of a specialization shall not
5120 contain default template argument values.
5122 So, for a partial specialization, or for a function template
5123 (in C++98/C++03), we look at all of them. */
5124 ;
5125 else
5126 /* But, for a primary class template that is not a partial
5127 specialization we look at all template parameters except the
5128 innermost ones. */
5131 /* Figure out what error message to issue. */
5146 else
5147 /* Per [temp.param]/9, "A default template-argument shall not be
5148 specified in the template-parameter-lists of the definition of
5149 a member of a class template that appears outside of the member's
5150 class.", thus if we aren't handling a member of a class template
5151 there is no need to examine the parameters. */
5155 /* If we're inside a class definition, there's no need to
5156 examine the parameters to the class itself. On the one
5157 hand, they will be checked when the class is defined, and,
5158 on the other, default arguments are valid in things like:
5159 template <class T = double>
5160 struct S { template <class U> void f(U); };
5161 Here the default argument for `S' has no bearing on the
5162 declaration of `f'. */
5164 else
5165 /* Check everything. */
5171 {
5178 {
5183 {
5185 {
5192 }
5194 /* Clear out the default argument so that we are not
5195 confused later. */
5197 }
5198 }
5200 /* At this point, if we're still interested in issuing messages,
5201 they must apply to classes surrounding the object declared. */
5205 }
5208 }
5210 /* Worker for push_template_decl_real, called via
5211 for_each_template_parm. DATA is really an int, indicating the
5212 level of the parameters we are interested in. If T is a template
5213 parameter of that level, return nonzero. */
5215 static int
5217 {
5223 else
5226 }
5228 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5229 DATA is really an int, indicating the innermost outer level of parameters.
5230 If T is a template parameter of that level or further out, return
5231 nonzero. */
5233 static int
5235 {
5241 else
5244 }
5246 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5247 parameters given by current_template_args, or reuses a
5248 previously existing one, if appropriate. Returns the DECL, or an
5249 equivalent one, if it is replaced via a call to duplicate_decls.
5251 If IS_FRIEND is true, DECL is a friend declaration. */
5253 tree
5255 {
5256 tree tmpl;
5257 tree args;
5258 tree info;
5259 tree ctx;
5263 /* True if the template is a member template, in the sense of
5264 [temp.mem]. */
5270 /* See if this is a partial specialization. */
5283 /* For a friend, we want the context of the friend, not
5284 the type of which it is a friend. */
5288 /* In the case of a virtual function, we want the class in which
5289 it is defined. */
5291 else
5292 /* Otherwise, if we're currently defining some class, the DECL
5293 is assumed to be a member of the class. */
5302 /* See if this is a primary template. */
5305 /* A friend template that specifies a class context, i.e.
5306 template <typename T> friend void A<T>::f();
5307 is not primary. */
5312 else
5316 {
5323 {
5326 }
5328 {
5330 {
5333 }
5335 {
5336 /* [temp.mem]
5338 A destructor shall not be a member template. */
5341 }
5348 {
5349 /* [basic.stc.dynamic.allocation]
5351 An allocation function can be a function
5352 template. ... Template allocation functions shall
5353 have two or more parameters. */
5356 }
5357 }
5360 {
5361 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5364 {
5370 }
5371 }
5374 /* alias-declaration */
5378 else
5379 {
5382 }
5383 }
5385 /* Check to see that the rules regarding the use of default
5386 arguments are not being violated. We check args for a friend
5387 functions when we know whether it's a definition, introducing
5388 declaration or re-declaration. */
5393 /* Ensure that there are no parameter packs in the type of this
5394 declaration that have not been expanded. */
5396 {
5397 /* Check each of the arguments individually to see if there are
5398 any bare parameter packs. */
5404 {
5407 {
5408 /* This is a PARM_DECL that contains unexpanded parameter
5409 packs. We have already complained about this in the
5410 check_for_bare_parameter_packs call, so just replace
5411 these types with ERROR_MARK_NODE. */
5414 }
5418 }
5420 /* Check for bare parameter packs in the return type and the
5421 exception specifiers. */
5423 /* Errors were already issued, set return type to int
5424 as the frontend doesn't expect error_mark_node as
5425 the return type. */
5429 }
5434 {
5437 }
5450 {
5455 /* If DECL is a TYPE_DECL for a class-template, then there won't
5456 be DECL_LANG_SPECIFIC. The information equivalent to
5457 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5461 {
5462 /* Since a template declaration already existed for this
5463 class-type, we must be redeclaring it here. Make sure
5464 that the redeclaration is valid. */
5466 current_template_parms,
5468 /* We don't need to create a new TEMPLATE_DECL; just use the
5469 one we already had. */
5471 }
5472 else
5473 {
5475 member_template_p);
5480 {
5481 /* A specialization of a member template of a template
5482 class. */
5486 }
5487 }
5488 }
5489 else
5490 {
5496 {
5499 }
5507 {
5508 tree new_tmpl;
5510 /* The declaration is a specialization of a member
5511 template, declared outside the class. Therefore, the
5512 innermost template arguments will be NULL, so we
5513 replace them with the arguments determined by the
5514 earlier call to check_explicit_specialization. */
5517 new_tmpl
5519 member_template_p);
5529 args,
5532 }
5534 /* Make sure the template headers we got make sense. */
5539 {
5544 }
5545 else
5547 {
5552 {
5556 else
5560 /* Avoid crash in import_export_decl. */
5563 }
5568 /* Can happen in erroneous input. */
5570 else
5572 }
5574 /* Check that the parms are used in the appropriate qualifying scopes
5575 in the declarator. */
5579 {
5585 /* Avoid crash in import_export_decl. */
5588 }
5589 }
5594 /* Push template declarations for global functions and types. Note
5595 that we do not try to push a global template friend declared in a
5596 template class; such a thing may well depend on the template
5597 parameters of the class. */
5600 {
5605 /* Hide template friend classes that haven't been declared yet. */
5607 {
5610 }
5611 }
5614 {
5619 /* Give template template parms a DECL_CONTEXT of the template
5620 for which they are a parameter. */
5623 {
5627 }
5633 }
5635 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5636 back to its most general template. If TMPL is a specialization,
5637 ARGS may only have the innermost set of arguments. Add the missing
5638 argument levels if necessary. */
5646 else
5647 {
5652 }
5655 && !is_friend
5658 /* Set DECL_COMDAT on template instantiations; if we force
5659 them to be emitted by explicit instantiation or -frepo,
5660 mark_needed will tell cgraph to do the right thing. */
5664 }
5666 tree
5668 {
5670 }
5672 /* FN is an inheriting constructor that inherits from the constructor
5673 template INHERITED; turn FN into a constructor template with a matching
5674 template header. */
5676 tree
5678 {
5679 tree inner_parms
5682 tree parms
5693 }
5695 /* Called when a class template TYPE is redeclared with the indicated
5696 template PARMS, e.g.:
5698 template <class T> struct S;
5699 template <class T> struct S {}; */
5701 bool
5703 {
5704 tree tmpl;
5705 tree tmpl_parms;
5709 {
5712 }
5716 /* The type is nested in some template class. Nothing to worry
5717 about here; there are no new template parameters for the nested
5718 type. */
5722 {
5724 tmpl);
5726 }
5732 {
5742 }
5745 {
5746 tree tmpl_parm;
5747 tree parm;
5748 tree tmpl_default;
5749 tree parm_default;
5763 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5764 TEMPLATE_DECL. */
5774 {
5778 }
5781 {
5782 /* We have in [temp.param]:
5784 A template-parameter may not be given default arguments
5785 by two different declarations in the same scope. */
5790 }
5793 /* Update the previous template parameters (which are the ones
5794 that will really count) with the new default value. */
5797 /* Update the new parameters, too; they'll be used as the
5798 parameters for any members. */
5801 /* Give each template template parm in this redeclaration a
5802 DECL_CONTEXT of the template for which they are a parameter. */
5804 {
5807 }
5811 }
5813 // Cannot redeclare a class template with a different set of constraints.
5815 {
5820 }
5823 }
5825 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5826 to be used when the caller has already checked
5827 (processing_template_decl
5828 && !instantiation_dependent_expression_p (expr)
5829 && potential_constant_expression (expr))
5830 and cleared processing_template_decl. */
5832 tree
5834 {
5837 complain,
5841 }
5843 /* Simplify EXPR if it is a non-dependent expression. Returns the
5844 (possibly simplified) expression. */
5846 tree
5848 {
5852 /* If we're in a template, but EXPR isn't value dependent, simplify
5853 it. We're supposed to treat:
5855 template <typename T> void f(T[1 + 1]);
5856 template <typename T> void f(T[2]);
5858 as two declarations of the same function, for example. */
5861 {
5862 processing_template_decl_sentinel s;
5864 }
5866 }
5868 tree
5870 {
5872 }
5874 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5875 an uninstantiated expression. */
5877 tree
5879 {
5883 {
5886 else
5887 {
5888 processing_template_decl_sentinel s;
5890 }
5891 }
5893 }
5895 /* True iff T is a specialization of a variable template. */
5897 bool
5899 {
5904 }
5906 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5907 template declaration, or a TYPE_DECL for an alias declaration. */
5909 bool
5911 {
5919 }
5921 /* Return TRUE iff T is a specialization of an alias template. */
5923 bool
5925 {
5926 /* It's an alias template specialization if it's an alias and its
5927 TYPE_NAME is a specialization of a primary template. */
5933 }
5935 /* An alias template is complex from a SFINAE perspective if a template-id
5936 using that alias can be ill-formed when the expansion is not, as with
5937 the void_t template. We determine this by checking whether the
5938 expansion for the alias template uses all its template parameters. */
5940 struct uses_all_template_parms_data
5941 {
5944 };
5946 static int
5948 {
5956 }
5958 static bool
5960 {
5975 }
5977 /* Return TRUE iff T is a specialization of a complex alias template with
5978 dependent template-arguments. */
5980 bool
5982 {
5995 }
5997 /* Return the number of innermost template parameters in TMPL. */
5999 static int
6001 {
6004 }
6006 /* Return either TMPL or another template that it is equivalent to under DR
6007 1286: An alias that just changes the name of a template is equivalent to
6008 the other template. */
6010 static tree
6012 {
6015 {
6016 /* Determine if the alias is equivalent to an underlying template. */
6028 tree alias_args = INNERMOST_TEMPLATE_ARGS
6033 /* Alias is equivalent. Strip it and repeat. */
6035 }
6038 }
6040 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6041 must be a reference-to-function or a pointer-to-function type, as specified
6042 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6043 and check that the resulting function has external linkage. */
6045 static tree
6047 tsubst_flags_t complain)
6048 {
6051 linkage_kind linkage;
6066 /* [temp.arg.nontype]/1
6068 A template-argument for a non-type, non-template template-parameter
6069 shall be one of:
6070 [...]
6071 -- the address of an object or function with external [C++11: or
6072 internal] linkage. */
6075 {
6077 {
6083 else
6086 }
6088 }
6092 {
6094 {
6099 else
6103 }
6105 }
6107 accept:
6114 }
6116 /* Subroutine of convert_nontype_argument.
6117 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6118 Emit an error otherwise. */
6120 static bool
6122 tsubst_flags_t complain)
6123 {
6140 {
6145 else
6147 }
6149 }
6151 /* Returns TRUE iff the address of OP is value-dependent.
6153 14.6.2.4 [temp.dep.temp]:
6154 A non-integral non-type template-argument is dependent if its type is
6155 dependent or it has either of the following forms
6156 qualified-id
6157 & qualified-id
6158 and contains a nested-name-specifier which specifies a class-name that
6159 names a dependent type.
6161 We generalize this to just say that the address of a member of a
6162 dependent class is value-dependent; the above doesn't cover the
6163 address of a static data member named with an unqualified-id. */
6165 static bool
6167 {
6168 /* We could use get_inner_reference here, but there's no need;
6169 this is only relevant for template non-type arguments, which
6170 can only be expressed as &id-expression. */
6172 {
6176 }
6179 }
6181 /* The next set of functions are used for providing helpful explanatory
6182 diagnostics for failed overload resolution. Their messages should be
6183 indented by two spaces for consistency with the messages in
6184 call.c */
6186 static int
6188 {
6190 }
6192 /* Other failure functions should call this one, to provide a single function
6193 for setting a breakpoint on. */
6195 static int
6197 {
6199 }
6201 static int
6203 {
6208 }
6210 static int
6212 {
6218 }
6220 static int
6222 {
6226 }
6228 static int
6230 {
6233 " template parameter %qD is not a parameter pack, but "
6237 }
6239 static int
6241 {
6244 " template argument %qE does not match "
6248 }
6250 static int
6252 {
6256 }
6258 static int
6260 {
6266 }
6268 static int
6270 {
6272 {
6277 else
6279 " deduced conflicting values for non-type parameter "
6281 }
6283 }
6285 static int
6287 {
6290 " variable-sized array type %qT is not "
6292 arg);
6294 }
6296 static int
6298 {
6302 arg);
6304 }
6306 static int
6308 {
6310 {
6316 else
6321 }
6323 }
6325 static int
6327 {
6329 }
6331 static int
6334 {
6336 }
6338 static int
6341 {
6347 }
6349 static int
6352 {
6355 {
6363 }
6365 }
6367 static int
6369 {
6372 " template parameters of a template template argument are "
6375 }
6377 static int
6379 {
6385 }
6387 static int
6389 {
6394 }
6396 /* Attempt to convert the non-type template parameter EXPR to the
6397 indicated TYPE. If the conversion is successful, return the
6398 converted value. If the conversion is unsuccessful, return
6399 NULL_TREE if we issued an error message, or error_mark_node if we
6400 did not. We issue error messages for out-and-out bad template
6401 parameters, but not simply because the conversion failed, since we
6402 might be just trying to do argument deduction. Both TYPE and EXPR
6403 must be non-dependent.
6405 The conversion follows the special rules described in
6406 [temp.arg.nontype], and it is much more strict than an implicit
6407 conversion.
6409 This function is called twice for each template argument (see
6410 lookup_template_class for a more accurate description of this
6411 problem). This means that we need to handle expressions which
6412 are not valid in a C++ source, but can be created from the
6413 first call (for instance, casts to perform conversions). These
6414 hacks can go away after we fix the double coercion problem. */
6416 static tree
6418 {
6419 tree expr_type;
6423 /* Detect immediately string literals as invalid non-type argument.
6424 This special-case is not needed for correctness (we would easily
6425 catch this later), but only to provide better diagnostic for this
6426 common user mistake. As suggested by DR 100, we do not mention
6427 linkage issues in the diagnostic as this is not the point. */
6428 /* FIXME we're making this OK. */
6430 {
6436 }
6438 /* Add the ADDR_EXPR now for the benefit of
6439 value_dependent_expression_p. */
6442 {
6446 }
6448 /* If we are in a template, EXPR may be non-dependent, but still
6449 have a syntactic, rather than semantic, form. For example, EXPR
6450 might be a SCOPE_REF, rather than the VAR_DECL to which the
6451 SCOPE_REF refers. Preserving the qualifying scope is necessary
6452 so that access checking can be performed when the template is
6453 instantiated -- but here we need the resolved form so that we can
6454 convert the argument. */
6466 /* If the argument is non-dependent, perform any conversions in
6467 non-dependent context as well. */
6475 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6476 to a non-type argument of "nullptr". */
6480 /* In C++11, integral or enumeration non-type template arguments can be
6481 arbitrary constant expressions. Pointer and pointer to
6482 member arguments can be general constant expressions that evaluate
6483 to a null value, but otherwise still need to be of a specific form. */
6485 {
6487 /* A PTRMEM_CST is already constant, and a valid template
6488 argument for a parameter of pointer to member type, we just want
6489 to leave it in that form rather than lower it to a
6493 {
6494 /* C++17: A template-argument for a non-type template-parameter shall
6495 be a converted constant expression (8.20) of the type of the
6496 template-parameter. */
6502 }
6504 {
6509 }
6510 }
6514 else
6517 /* HACK: Due to double coercion, we can get a
6518 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6519 which is the tree that we built on the first call (see
6520 below when coercing to reference to object or to reference to
6521 function). We just strip everything and get to the arg.
6522 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6523 for examples. */
6525 {
6531 {
6532 /* ??? Maybe we could use convert_from_reference here, but we
6533 would need to relax its constraints because the NOP_EXPR
6534 could actually change the type to something more cv-qualified,
6535 and this is not folded by convert_from_reference. */
6540 && (same_type_ignoring_top_level_qualifiers_p
6543 {
6546 }
6547 }
6548 }
6550 /* [temp.arg.nontype]/5, bullet 1
6552 For a non-type template-parameter of integral or enumeration type,
6553 integral promotions (_conv.prom_) and integral conversions
6554 (_conv.integral_) are applied. */
6556 {
6558 {
6563 }
6568 /* Notice that there are constant expressions like '4 % 0' which
6569 do not fold into integer constants. */
6572 {
6574 {
6578 else
6584 /* else cxx_constant_value complained but gave us
6585 a real constant, so go ahead. */
6587 {
6588 /* Some assemble time constant expressions like
6589 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6590 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6591 as we can emit them into .rodata initializers of
6592 variables, yet they can't fold into an INTEGER_CST at
6593 compile time. Refuse them here. */
6598 }
6599 }
6600 else
6602 }
6604 /* Avoid typedef problems. */
6607 }
6608 /* [temp.arg.nontype]/5, bullet 2
6610 For a non-type template-parameter of type pointer to object,
6611 qualification conversions (_conv.qual_) and the array-to-pointer
6612 conversion (_conv.array_) are applied. */
6614 {
6617 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6618 decay_conversion or an explicit cast. If it's a problematic cast,
6619 we'll complain about it below. */
6621 {
6626 {
6629 }
6630 }
6632 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6634 A template-argument for a non-type, non-template template-parameter
6635 shall be one of: [...]
6637 -- the name of a non-type template-parameter;
6638 -- the address of an object or function with external linkage, [...]
6639 expressed as "& id-expression" where the & is optional if the name
6640 refers to a function or array, or if the corresponding
6641 template-parameter is a reference.
6643 Here, we do not care about functions, as they are invalid anyway
6644 for a parameter of type pointer-to-object. */
6647 /* Non-type template parameters are OK. */
6648 ;
6652 {
6654 {
6657 "because %qD is a variable, not the address of "
6660 }
6662 {
6668 }
6669 /* Other values, like integer constants, might be valid
6670 non-type arguments of some other type. */
6672 }
6673 else
6674 {
6678 {
6683 }
6685 {
6691 }
6694 {
6699 }
6700 /* C++17: For a non-type template-parameter of reference or pointer
6701 type, the value of the constant expression shall not refer to (or
6702 for a pointer type, shall not be the address of):
6703 * a subobject (4.5),
6704 * a temporary object (15.2),
6705 * a string literal (5.13.5),
6706 * the result of a typeid expression (8.2.8), or
6707 * a predefined __func__ variable (11.4.1). */
6709 {
6712 decl);
6714 }
6718 {
6723 }
6725 {
6729 decl);
6731 }
6732 }
6739 }
6740 /* [temp.arg.nontype]/5, bullet 3
6742 For a non-type template-parameter of type reference to object, no
6743 conversions apply. The type referred to by the reference may be more
6744 cv-qualified than the (otherwise identical) type of the
6745 template-argument. The template-parameter is bound directly to the
6746 template-argument, which must be an lvalue. */
6748 {
6750 expr_type))
6754 {
6759 }
6762 {
6767 }
6769 /* [temp.arg.nontype]/1
6771 A template-argument for a non-type, non-template template-parameter
6772 shall be one of: [...]
6774 -- the address of an object or function with external linkage. */
6777 {
6780 {
6783 "because a reference variable does not have a constant "
6786 }
6787 }
6791 /* OK, dependent reference. We don't want to ask whether a DECL is
6793 else
6794 {
6796 {
6802 }
6804 /* DR 1155 allows internal linkage in C++11 and up. */
6807 {
6813 }
6816 }
6820 }
6821 /* [temp.arg.nontype]/5, bullet 4
6823 For a non-type template-parameter of type pointer to function, only
6824 the function-to-pointer conversion (_conv.func_) is applied. If the
6825 template-argument represents a set of overloaded functions (or a
6826 pointer to such), the matching function is selected from the set
6827 (_over.over_). */
6829 {
6830 /* If the argument is a template-id, we might not have enough
6831 context information to decay the pointer. */
6833 {
6837 }
6840 /* Null pointer values are OK in C++11. */
6846 }
6847 /* [temp.arg.nontype]/5, bullet 5
6849 For a non-type template-parameter of type reference to function, no
6850 conversions apply. If the template-argument represents a set of
6851 overloaded functions, the matching function is selected from the set
6852 (_over.over_). */
6854 {
6856 {
6858 {
6863 }
6865 }
6870 }
6871 /* [temp.arg.nontype]/5, bullet 6
6873 For a non-type template-parameter of type pointer to member function,
6874 no conversions apply. If the template-argument represents a set of
6875 overloaded member functions, the matching member function is selected
6876 from the set (_over.over_). */
6878 {
6883 /* [temp.arg.nontype] bullet 1 says the pointer to member
6884 expression must be a pointer-to-member constant. */
6889 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6890 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6893 }
6894 /* [temp.arg.nontype]/5, bullet 7
6896 For a non-type template-parameter of type pointer to data member,
6897 qualification conversions (_conv.qual_) are applied. */
6899 {
6900 /* [temp.arg.nontype] bullet 1 says the pointer to member
6901 expression must be a pointer-to-member constant. */
6909 }
6911 {
6913 {
6918 }
6920 }
6921 /* A template non-type parameter must be one of the above. */
6922 else
6925 /* Sanity check: did we actually convert the argument to the
6926 right type? */
6930 }
6932 /* Subroutine of coerce_template_template_parms, which returns 1 if
6933 PARM_PARM and ARG_PARM match using the rule for the template
6934 parameters of template template parameters. Both PARM and ARG are
6935 template parameters; the rest of the arguments are the same as for
6936 coerce_template_template_parms.
6937 */
6938 static int
6940 tree arg,
6941 tsubst_flags_t complain,
6942 tree in_decl,
6943 tree outer_args)
6944 {
6953 {
6955 /* We encounter instantiations of templates like
6956 template <template <template <class> class> class TT>
6957 class C; */
6958 {
6965 }
6966 /* Fall through. */
6971 /* Argument is a parameter pack but parameter is not. */
6976 /* The tsubst call is used to handle cases such as
6978 template <int> class C {};
6979 template <class T, template <T> class TT> class D {};
6980 D<int, C> d;
6982 i.e. the parameter list of TT depends on earlier parameters. */
6984 {
6989 }
6993 /* Argument is a parameter pack but parameter is not. */
7000 }
7003 }
7005 /* Coerce template argument list ARGLIST for use with template
7006 template-parameter TEMPL. */
7008 static tree
7010 tsubst_flags_t complain)
7011 {
7012 /* Consider an example where a template template parameter declared as
7014 template <class T, class U = std::allocator<T> > class TT
7016 The template parameter level of T and U are one level larger than
7017 of TT. To proper process the default argument of U, say when an
7018 instantiation `TT<int>' is seen, we need to build the full
7019 arguments containing {int} as the innermost level. Outer levels,
7020 available when not appearing as default template argument, can be
7021 obtained from the arguments of the enclosing template.
7023 Suppose that TT is later substituted with std::vector. The above
7024 instantiation is `TT<int, std::allocator<T> >' with TT at
7025 level 1, and T at level 2, while the template arguments at level 1
7026 becomes {std::vector} and the inner level 2 is {int}. */
7030 {
7032 /* We want arguments for the partial specialization, not arguments for
7033 the primary template. */
7035 else
7037 }
7039 {
7040 /* This is an argument of the current template, so we haven't set
7041 DECL_CONTEXT yet. */
7042 tree relevant_template_parms;
7044 /* Parameter levels that are greater than the level of the given
7045 template template parm are irrelevant. */
7052 }
7059 complain,
7062 }
7064 /* A cache of template template parameters with match-all default
7065 arguments. */
7067 static void
7069 {
7073 }
7074 static tree
7076 {
7081 }
7083 /* T is a bound template template-parameter. Copy its arguments into default
7084 arguments of the template template-parameter's template parameters. */
7086 static tree
7088 {
7111 {
7114 {
7117 }
7118 }
7122 }
7124 /* ARG is a bound potential template template-argument, and PARGS is a list
7125 of arguments for the corresponding template template-parameter. Adjust
7126 PARGS as appropriate for application to ARG's template, and if ARG is a
7127 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7128 arguments to the template template parameter. */
7130 static tree
7132 {
7136 {
7137 /* When comparing two template template-parameters in partial ordering,
7138 rewrite the one currently being used as an argument to have default
7139 arguments for all parameters. */
7145 }
7146 else
7147 {
7148 tree aparms
7153 }
7156 }
7158 /* Subroutine of unify for the case when PARM is a
7159 BOUND_TEMPLATE_TEMPLATE_PARM. */
7161 static int
7164 {
7168 /* The template template parm might be variadic and the argument
7169 not, so flatten both argument lists. */
7174 {
7175 /* In keeping with P0522R0, adjust P's template arguments
7176 to apply to A's template; then flatten it again. */
7185 /* If the P0522 adjustment eliminated a pack expansion, deduce
7186 empty packs. */
7192 }
7193 else
7194 {
7195 /* Deduce arguments T, i from TT<T> or TT<i>.
7196 We check each element of PARMVEC and ARGVEC individually
7197 rather than the whole TREE_VEC since they can have
7198 different number of elements, which is allowed under N2555. */
7202 /* Check if the parameters end in a pack, making them
7203 variadic. */
7210 /* If the template argument list of P contains a pack
7211 expansion that is not the last template argument, the
7212 entire template argument list is a non-deduced
7213 context. */
7231 DEDUCE_EXACT,
7234 }
7237 }
7239 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7240 template template parameters. Both PARM_PARMS and ARG_PARMS are
7241 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7242 or PARM_DECL.
7244 Consider the example:
7245 template <class T> class A;
7246 template<template <class U> class TT> class B;
7248 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7249 the parameters to A, and OUTER_ARGS contains A. */
7251 static int
7253 tree arg_parms,
7254 tsubst_flags_t complain,
7255 tree in_decl,
7256 tree outer_args)
7257 {
7269 {
7270 /* P0522R0: A template template-parameter P is at least as specialized as
7271 a template template-argument A if, given the following rewrite to two
7272 function templates, the function template corresponding to P is at
7273 least as specialized as the function template corresponding to A
7274 according to the partial ordering rules for function templates
7275 ([temp.func.order]). Given an invented class template X with the
7276 template parameter list of A (including default arguments):
7278 * Each of the two function templates has the same template parameters,
7279 respectively, as P or A.
7281 * Each function template has a single function parameter whose type is
7282 a specialization of X with template arguments corresponding to the
7283 template parameters from the respective function template where, for
7284 each template parameter PP in the template parameter list of the
7285 function template, a corresponding template argument AA is formed. If
7286 PP declares a parameter pack, then AA is the pack expansion
7287 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7289 If the rewrite produces an invalid type, then P is not at least as
7290 specialized as A. */
7292 /* So coerce P's args to apply to A's parms, and then deduce between A's
7293 args and the converted args. If that succeeds, A is at least as
7294 specialized as P, so they match.*/
7301 {
7307 }
7308 }
7310 /* Determine whether we have a parameter pack at the end of the
7311 template template parameter's template parameter list. */
7313 {
7320 {
7334 }
7335 }
7341 /* Check all of the template parameters except the parameter pack at
7342 the end (if any). */
7344 {
7353 outer_args))
7356 }
7359 {
7360 /* Check each of the template parameters in the template
7361 argument against the template parameter pack at the end of
7362 the template template parameter. */
7369 {
7376 outer_args))
7378 }
7379 }
7382 }
7384 /* Verifies that the deduced template arguments (in TARGS) for the
7385 template template parameters (in TPARMS) represent valid bindings,
7386 by comparing the template parameter list of each template argument
7387 to the template parameter list of its corresponding template
7388 template parameter, in accordance with DR150. This
7389 routine can only be called after all template arguments have been
7390 deduced. It will return TRUE if all of the template template
7391 parameter bindings are okay, FALSE otherwise. */
7392 bool
7394 {
7398 /* We're dealing with template parms in this process. */
7404 {
7409 {
7414 {
7415 /* Look inside the argument pack. */
7418 }
7421 {
7425 /* Extract the next argument from the argument
7426 pack. */
7430 /* Look at the pattern of the pack expansion. */
7433 /* Extract the template parameters from the template
7434 argument. */
7440 /* Verify that we can coerce the template template
7441 parameters from the template argument to the template
7442 parameter. This requires an exact match. */
7444 && !coerce_template_template_parms
7446 targ_parms,
7447 tf_none,
7448 tparm,
7449 targs))
7450 {
7453 }
7454 }
7455 }
7456 }
7458 out:
7462 }
7464 /* Since type attributes aren't mangled, we need to strip them from
7465 template type arguments. */
7467 static tree
7469 {
7479 }
7481 /* And from inside dependent non-type arguments like sizeof(Type). */
7483 static tree
7485 {
7495 }
7497 // A template declaration can be substituted for a constrained
7498 // template template parameter only when the argument is more
7499 // constrained than the parameter.
7500 static bool
7502 {
7505 /* For now, allow constrained template template arguments
7506 and unconstrained template template parameters. */
7512 // If the template parameter is constrained, we need to rewrite its
7513 // constraints in terms of the ARG's template parameters. This ensures
7514 // that all of the template parameter types will have the same depth.
7515 //
7516 // Note that this is only valid when coerce_template_template_parm is
7517 // true for the innermost template parameters of PARM and ARG. In other
7518 // words, because coercion is successful, this conversion will be valid.
7520 {
7527 }
7530 }
7532 // Convert a placeholder argument into a binding to the original
7533 // parameter. The original parameter is saved as the TREE_TYPE of
7534 // ARG.
7537 {
7540 }
7542 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7543 because one of them is dependent. But we need to represent the
7544 conversion for the benefit of cp_tree_equal. */
7546 static tree
7548 {
7549 /* Auto parms get no conversion. */
7552 /* We don't need or want to add this conversion now if we're going to use the
7553 argument for deduction. */
7565 }
7567 /* Convert the indicated template ARG as necessary to match the
7568 indicated template PARM. Returns the converted ARG, or
7569 error_mark_node if the conversion was unsuccessful. Error and
7570 warning messages are issued under control of COMPLAIN. This
7571 conversion is for the Ith parameter in the parameter list. ARGS is
7572 the full set of template arguments deduced so far. */
7574 static tree
7576 tree arg,
7577 tree args,
7578 tsubst_flags_t complain,
7580 tree in_decl)
7581 {
7582 tree orig_arg;
7583 tree val;
7589 /* Trivially convert placeholders. */
7598 {
7599 /* The template argument was the name of some
7600 member function. That's usually
7601 invalid, but static members are OK. In any
7602 case, grab the underlying fields/functions
7603 and issue an error later if required. */
7606 }
7614 /* When determining whether an argument pack expansion is a template,
7615 look at the pattern. */
7619 /* Deal with an injected-class-name used as a template template arg. */
7621 {
7624 {
7634 }
7635 }
7637 is_tmpl_type =
7653 {
7655 {
7659 }
7662 "to refer to a type member of a template parameter, "
7667 typename_type,
7668 complain);
7671 }
7673 {
7675 {
7677 {
7689 else
7692 }
7693 }
7695 }
7697 {
7699 {
7706 else
7709 }
7711 }
7714 /* We already did the appropriate conversion when packing args. */
7717 {
7719 {
7721 /* The number of argument required is not known yet.
7722 Just accept it for now. */
7724 else
7725 {
7727 tree argparm;
7729 /* Strip alias templates that are equivalent to another
7730 template. */
7736 args))
7737 {
7740 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7741 TEMPLATE_DECL. */
7743 {
7748 }
7749 }
7750 else
7751 {
7753 {
7760 }
7763 }
7765 // Check that the constraints are compatible before allowing the
7766 // substitution.
7769 {
7771 {
7777 }
7779 }
7780 }
7781 }
7782 else
7784 /* We only form one instance of each template specialization.
7785 Therefore, if we use a non-canonical variant (i.e., a
7786 typedef), any future messages referring to the type will use
7787 the typedef, which is confusing if those future uses do not
7788 themselves also use the typedef. */
7791 }
7792 else
7793 {
7797 {
7801 }
7802 else
7810 /* We used to call digest_init here. However, digest_init
7811 will report errors, which we don't want when complain
7812 is zero. More importantly, digest_init will try too
7813 hard to convert things: for example, `0' should not be
7814 converted to pointer type at this point according to
7815 the standard. Accepting this is not merely an
7816 extension, since deciding whether or not these
7817 conversions can occur is part of determining which
7818 function template to call, or whether a given explicit
7819 argument specification is valid. */
7821 else
7822 {
7825 }
7835 {
7836 /* Reject template arguments that are references to built-in
7837 functions with no library fallbacks. */
7846 }
7849 {
7850 /* Strip typedefs from the SCOPE_REF. */
7853 complain);
7856 }
7857 }
7860 }
7862 /* Coerces the remaining template arguments in INNER_ARGS (from
7863 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7864 Returns the coerced argument pack. PARM_IDX is the position of this
7865 parameter in the template parameter list. ARGS is the original
7866 template argument list. */
7867 static tree
7870 tree args,
7871 tree inner_args,
7873 tree new_args,
7875 tree in_decl,
7876 tsubst_flags_t complain)
7877 {
7880 tree packed_args;
7881 tree argument_pack;
7888 {
7889 /* When the template parameter is a non-type template parameter pack
7890 or template template parameter pack whose type or template
7891 parameters use parameter packs, we know exactly how many arguments
7892 we are looking for. Build a vector of the instantiated decls for
7893 these template parameters in PACKED_PARMS. */
7894 /* We can't use make_pack_expansion here because it would interpret a
7895 _DECL as a use rather than a declaration. */
7909 /* If we're doing a partial instantiation of a member template,
7910 verify that all of the types used for the non-type
7911 template parameter pack are, in fact, valid for non-type
7912 template parameters. */
7915 {
7918 {
7922 }
7923 /* We don't know how many args we have yet, just
7924 use the unconverted ones for now. */
7926 }
7929 }
7930 /* Check if we have a placeholder pack, which indicates we're
7931 in the context of a introduction list. In that case we want
7932 to match this pack to the single placeholder. */
7936 {
7939 }
7940 else
7943 /* Convert the remaining arguments, which will be a part of the
7944 parameter pack "parm". */
7947 {
7953 {
7954 /* Once we've packed as many args as we have types, stop. */
7958 /* We don't know how many args we have yet, just
7959 use the unconverted ones for now. */
7961 else
7963 }
7966 {
7969 }
7970 else
7973 in_decl);
7977 }
7981 {
7986 }
7991 else
7992 {
7995 }
8002 }
8004 /* Returns the number of pack expansions in the template argument vector
8005 ARGS. */
8007 static int
8009 {
8014 {
8018 }
8020 }
8022 /* Convert all template arguments to their appropriate types, and
8023 return a vector containing the innermost resulting template
8024 arguments. If any error occurs, return error_mark_node. Error and
8025 warning messages are issued under control of COMPLAIN.
8027 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8028 for arguments not specified in ARGS. Otherwise, if
8029 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8030 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8031 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8032 ARGS. */
8034 static tree
8036 tree args,
8037 tree in_decl,
8038 tsubst_flags_t complain,
8041 {
8043 tree orig_inner_args;
8044 tree inner_args;
8045 tree new_args;
8046 tree new_inner_args;
8050 /* When used as a boolean value, indicates whether this is a
8051 variadic template parameter list. Since it's an int, we can also
8052 subtract it from nparms to get the number of non-variadic
8053 parameters. */
8058 /* Likewise for parameters with default arguments. */
8066 /* Determine if there are any parameter packs or default arguments. */
8068 {
8076 }
8079 /* If there are no parameters that follow a parameter pack, we need to
8080 expand any argument packs so that we can deduce a parameter pack from
8081 some non-packed args followed by an argument pack, as in variadic85.C.
8082 If there are such parameters, we need to leave argument packs intact
8083 so the arguments are assigned properly. This can happen when dealing
8084 with a nested class inside a partial specialization of a class
8085 template, as in variadic92.C, or when deducing a template parameter pack
8086 from a sub-declarator, as in variadic114.C. */
8090 /* Count any pack expansion args. */
8096 && require_all_args
8097 && !variadic_args_p
8098 && (!use_default_args
8101 {
8103 {
8105 {
8109 }
8110 else
8117 }
8120 }
8121 /* We can't pass a pack expansion to a non-pack parameter of an alias
8122 template (DR 1430). */
8126 && variadic_args_p
8128 {
8130 {
8132 {
8138 {
8141 "pack expansion argument for non-pack parameter "
8143 else
8145 "pack expansion argument for non-pack parameter "
8149 }
8150 }
8152 found:;
8153 }
8155 }
8157 /* We need to evaluate the template arguments, even though this
8158 template-id may be nested within a "sizeof". */
8167 {
8168 tree arg;
8169 tree parm;
8171 /* Get the Ith template parameter. */
8175 {
8178 }
8180 /* Calculate the next argument. */
8183 else
8188 {
8189 /* Some arguments will be placed in the
8190 template parameter pack PARM. */
8197 {
8198 /* We don't know how many args we have yet, just use the
8199 unconverted (and still packed) ones for now. */
8203 }
8207 /* Store this argument. */
8209 {
8210 lost++;
8211 /* We are done with all of the arguments. */
8213 }
8214 else
8215 {
8218 }
8221 }
8223 {
8225 {
8226 /* "If every valid specialization of a variadic template
8227 requires an empty template parameter pack, the template is
8228 ill-formed, no diagnostic required." So check that the
8229 pattern works with this parameter. */
8234 in_decl);
8236 {
8241 }
8243 /* Recover from missing typename. */
8247 /* We don't know how many args we have yet, just
8248 use the unconverted ones for now. */
8252 }
8253 }
8255 {
8256 /* There must be a default arg in this case. */
8259 /* The position of the first default template argument,
8260 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8261 Record that. */
8265 }
8266 else
8270 {
8273 }
8275 /* This only occurs if there was an error in the template
8276 parameter list itself (which we would already have
8277 reported) that we are trying to recover from, e.g., a class
8278 template with a parameter list such as
8279 template<typename..., typename>. */
8281 else
8287 lost++;
8289 }
8294 {
8296 {
8301 }
8303 }
8313 }
8315 /* Convert all template arguments to their appropriate types, and
8316 return a vector containing the innermost resulting template
8317 arguments. If any error occurs, return error_mark_node. Error and
8318 warning messages are not issued.
8320 Note that no function argument deduction is performed, and default
8321 arguments are used to fill in unspecified arguments. */
8322 tree
8324 {
8326 }
8328 /* Convert all template arguments to their appropriate type, and
8329 instantiate default arguments as needed. This returns a vector
8330 containing the innermost resulting template arguments, or
8331 error_mark_node if unsuccessful. */
8332 tree
8334 tsubst_flags_t complain)
8335 {
8337 }
8339 /* Like coerce_template_parms. If PARMS represents all template
8340 parameters levels, this function returns a vector of vectors
8341 representing all the resulting argument levels. Note that in this
8342 case, only the innermost arguments are coerced because the
8343 outermost ones are supposed to have been coerced already.
8345 Otherwise, if PARMS represents only (the innermost) vector of
8346 parameters, this function returns a vector containing just the
8347 innermost resulting arguments. */
8349 static tree
8351 tree args,
8352 tree in_decl,
8353 tsubst_flags_t complain,
8356 {
8359 tree coerced_args;
8362 {
8364 tree level;
8370 {
8371 tree l;
8375 require_all_args,
8376 use_default_args);
8377 else
8384 }
8385 }
8386 else
8389 require_all_args,
8390 use_default_args);
8392 }
8394 /* Returns 1 if template args OT and NT are equivalent. */
8396 int
8398 {
8407 /* For member templates */
8416 {
8433 }
8437 {
8440 /* Don't treat an alias template specialization with dependent
8441 arguments as equivalent to its underlying type when used as a
8442 template argument; we need them to be distinct so that we
8443 substitute into the specialization arguments at instantiation
8444 time. And aliases can't be equivalent without being ==, so
8445 we don't need to look any deeper.
8447 During partial ordering, however, we need to treat them normally so
8448 that we can order uses of the same alias with different
8449 cv-qualification (79960). */
8453 else
8455 }
8458 else
8459 {
8460 /* Try to treat a template non-type argument that has been converted
8461 to the parameter type as equivalent to one that hasn't yet. */
8474 }
8475 }
8477 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8478 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8479 NEWARG_PTR with the offending arguments if they are non-NULL. */
8481 int
8485 {
8498 {
8503 {
8509 }
8510 }
8512 }
8516 {
8518 }
8520 static void
8522 {
8532 /* We are called both from instantiate_decl, where we've already had a
8533 tinst_level pushed, and instantiate_template, where we haven't.
8534 Compensate. */
8545 else
8554 }
8557 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8558 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8559 documentation for TEMPLATE_ID_EXPR. */
8561 tree
8563 {
8564 tree type;
8572 {
8575 }
8578 {
8580 unknown_type_node,
8582 arglist);
8584 }
8591 }
8593 /* Within the scope of a template class S<T>, the name S gets bound
8594 (in build_self_reference) to a TYPE_DECL for the class, not a
8595 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8596 or one of its enclosing classes, and that type is a template,
8597 return the associated TEMPLATE_DECL. Otherwise, the original
8598 DECL is returned.
8600 Also handle the case when DECL is a TREE_LIST of ambiguous
8601 injected-class-names from different bases. */
8603 tree
8605 {
8609 /* DR 176: A lookup that finds an injected-class-name (10.2
8610 [class.member.lookup]) can result in an ambiguity in certain cases
8611 (for example, if it is found in more than one base class). If all of
8612 the injected-class-names that are found refer to specializations of
8613 the same class template, and if the name is followed by a
8614 template-argument-list, the reference refers to the class template
8615 itself and not a specialization thereof, and is not ambiguous. */
8617 {
8620 {
8626 }
8629 else
8631 }
8637 }
8639 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8640 parameters, find the desired type.
8642 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8644 IN_DECL, if non-NULL, is the template declaration we are trying to
8645 instantiate.
8647 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8648 the class we are looking up.
8650 Issue error and warning messages under control of COMPLAIN.
8652 If the template class is really a local class in a template
8653 function, then the FUNCTION_CONTEXT is the function in which it is
8654 being instantiated.
8656 ??? Note that this function is currently called *twice* for each
8657 template-id: the first time from the parser, while creating the
8658 incomplete type (finish_template_type), and the second type during the
8659 real instantiation (instantiate_template_class). This is surely something
8660 that we want to avoid. It also causes some problems with argument
8661 coercion (see convert_nontype_argument for more information on this). */
8663 static tree
8666 {
8668 tree t;
8671 spec_entry elt;
8672 hashval_t hash;
8675 {
8679 else
8680 {
8687 }
8690 }
8692 {
8695 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8696 an implicit typename for the second A. Deal with it. */
8701 {
8704 }
8705 }
8708 {
8711 }
8713 {
8717 }
8719 {
8722 }
8724 /* Issue an error message if we didn't find a template. */
8726 {
8730 }
8733 /* Make sure it's a user visible template, if it was named by
8734 the user. */
8737 {
8739 {
8743 }
8745 }
8749 /* An alias that just changes the name of a template is equivalent to the
8750 other template, so if any of the arguments are pack expansions, strip
8751 the alias to avoid problems with a pack expansion passed to a non-pack
8752 alias template parameter (DR 1430). */
8757 {
8758 tree parm;
8767 }
8768 else
8769 {
8771 tree gen_tmpl;
8772 tree type_decl;
8780 /* An error occurred while building the template TEMPL, and a
8781 diagnostic has most certainly been emitted for that
8782 already. Let's propagate that error. */
8791 {
8792 /* We've been given an incomplete set of template arguments.
8793 For example, given:
8795 template <class T> struct S1 {
8796 template <class U> struct S2 {};
8797 template <class U> struct S2<U*> {};
8798 };
8800 we will be called with an ARGLIST of `U*', but the
8801 TEMPLATE will be `template <class T> template
8802 <class U> struct S1<T>::S2'. We must fill in the missing
8803 arguments. */
8807 }
8809 /* Now we should have enough arguments. */
8812 /* From here on, we're only interested in the most general
8813 template. */
8815 /* Calculate the BOUND_ARGS. These will be the args that are
8816 actually tsubst'd into the definition to create the
8817 instantiation. */
8819 complain,
8824 /* We were unable to bind the arguments. */
8827 /* In the scope of a template class, explicit references to the
8828 template class refer to the type of the template, not any
8829 instantiation of it. For example, in:
8831 template <class T> class C { void f(C<T>); }
8833 the `C<T>' is just the same as `C'. Outside of the
8834 class, however, such a reference is an instantiation. */
8838 {
8843 }
8845 /* If we already have this specialization, return it. */
8855 /* If the the template's constraints are not satisfied,
8856 then we cannot form a valid type.
8858 Note that the check is deferred until after the hash
8859 lookup. This prevents redundant checks on previously
8860 instantiated specializations. */
8862 {
8864 {
8867 }
8869 }
8873 /* If the deduced arguments are invalid, then the binding
8874 failed. */
8878 complain))
8885 {
8890 }
8900 /* Create the type. */
8902 {
8903 /* The user referred to a specialization of an alias
8904 template represented by GEN_TMPL.
8906 [temp.alias]/2 says:
8908 When a template-id refers to the specialization of an
8909 alias template, it is equivalent to the associated
8910 type obtained by substitution of its
8911 template-arguments for the template-parameters in the
8912 type-id of the alias template. */
8915 /* Note that the call above (by indirectly calling
8916 register_specialization in tsubst_decl) registers the
8917 TYPE_DECL representing the specialization of the alias
8918 template. So next time someone substitutes ARGLIST for
8919 the template parms into the alias template (GEN_TMPL),
8920 she'll get that TYPE_DECL back. */
8924 }
8926 {
8928 {
8939 }
8940 else
8941 {
8942 /* We don't want to call start_enum for this type, since
8943 the values for the enumeration constants may involve
8944 template parameters. And, no one should be interested
8945 in the enumeration constants for such a type. */
8948 }
8952 }
8954 {
8955 /* Lambda closures are regenerated in tsubst_lambda_expr, not
8956 instantiated here. */
8964 /* A local class. Make sure the decl gets registered properly. */
8969 /* This instantiation is another name for the primary
8970 template type. Set the TYPE_CANONICAL field
8971 appropriately. */
8974 /* Some of the template arguments require structural
8975 equality testing, so this template class requires
8976 structural equality testing. */
8978 }
8979 else
8982 /* If we called start_enum or pushtag above, this information
8983 will already be set up. */
8985 {
8992 }
8993 else
8997 {
9003 {
9006 }
9007 }
9011 {
9015 {
9016 tree attributes
9024 }
9025 }
9027 /* Let's consider the explicit specialization of a member
9028 of a class template specialization that is implicitly instantiated,
9029 e.g.:
9030 template<class T>
9031 struct S
9032 {
9033 template<class U> struct M {}; //#0
9034 };
9036 template<>
9037 template<>
9038 struct S<int>::M<char> //#1
9039 {
9040 int i;
9041 };
9042 [temp.expl.spec]/4 says this is valid.
9044 In this case, when we write:
9045 S<int>::M<char> m;
9047 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9048 the one of #0.
9050 When we encounter #1, we want to store the partial instantiation
9051 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9053 For all cases other than this "explicit specialization of member of a
9054 class template", we just want to store the most general template into
9055 the CLASSTYPE_TI_TEMPLATE of M.
9057 This case of "explicit specialization of member of a class template"
9058 only happens when:
9059 1/ the enclosing class is an instantiation of, and therefore not
9060 the same as, the context of the most general template, and
9061 2/ we aren't looking at the partial instantiation itself, i.e.
9062 the innermost arguments are not the same as the innermost parms of
9063 the most general template.
9065 So it's only when 1/ and 2/ happens that we want to use the partial
9066 instantiation of the member template in lieu of its most general
9067 template. */
9071 /* the enclosing class must be an instantiation... */
9074 {
9078 tree partial_inst_args =
9085 use_partial_inst_tmpl =
9086 /*...and we must not be looking at the partial instantiation
9087 itself. */
9089 partial_inst_args);
9090 }
9093 /* This case is easy; there are no member templates involved. */
9095 else
9096 {
9097 /* This is a full instantiation of a member template. Find
9098 the partial instantiation of which this is an instance. */
9100 /* Temporarily reduce by one the number of levels in the ARGLIST
9101 so as to avoid comparing the last set of arguments. */
9105 /* FOUND is either a proper class type, or an alias
9106 template specialization. In the later case, it's a
9107 TYPE_DECL, resulting from the substituting of arguments
9108 for parameters in the TYPE_DECL of the alias template
9109 done earlier. So be careful while getting the template
9110 of FOUND. */
9112 ? found
9116 }
9118 // Build template info for the new specialization.
9127 /* Note this use of the partial instantiation so we can check it
9128 later in maybe_process_partial_specialization. */
9135 /* Now that the type has been registered on the instantiations
9136 list, we set up the enumerators. Because the enumeration
9137 constants may involve the enumeration type itself, we make
9138 sure to register the type first, and then create the
9139 constants. That way, doing tsubst_expr for the enumeration
9140 constants won't result in recursive calls here; we'll find
9141 the instantiation and exit above. */
9145 /* If the type makes use of template parameters, the
9146 code that generates debugging information will crash. */
9149 /* Possibly limit visibility based on template args. */
9156 }
9157 }
9159 /* Wrapper for lookup_template_class_1. */
9161 tree
9164 {
9165 tree ret;
9171 }
9173 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9175 tree
9177 {
9178 /* The type of the expression is NULL_TREE since the template-id could refer
9179 to an explicit or partial specialization. */
9182 /* Except that concepts are always bool. */
9185 }
9187 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9189 tree
9191 {
9195 /* We never want to return a VAR_DECL for a variable concept, since they
9196 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9211 {
9213 {
9216 }
9218 }
9220 /* If a template-id refers to a specialization of a variable
9221 concept, then the expression is true if and only if the
9222 concept's constraints are satisfied by the given template
9223 arguments.
9225 NOTE: This is an extension of Concepts Lite TS that
9226 allows constraints to be used in expressions. */
9228 {
9231 }
9234 }
9236 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9237 TARGS template args, and instantiate it if it's not dependent. */
9239 tree
9241 tsubst_flags_t complain)
9242 {
9245 {
9248 }
9251 }
9253 \f
9254 struct pair_fn_data
9255 {
9256 tree_fn_t fn;
9257 tree_fn_t any_fn;
9259 /* True when we should also visit template parameters that occur in
9260 non-deduced contexts. */
9263 };
9265 /* Called from for_each_template_parm via walk_tree. */
9267 static tree
9269 {
9276 #define WALK_SUBTREE(NODE) \
9277 do \
9278 { \
9279 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9280 pfd->include_nondeduced_p, \
9281 pfd->any_fn); \
9282 if (result) goto out; \
9283 } \
9284 while (0)
9294 {
9298 /* Fall through. */
9304 else
9314 /* Since we're not going to walk subtrees, we have to do this
9315 explicitly here. */
9317 /* Fall through. */
9320 /* Check the return type. */
9323 /* Check the parameter types. Since default arguments are not
9324 instantiated until they are needed, the TYPE_ARG_TYPES may
9325 contain expressions that involve template parameters. But,
9326 no-one should be looking at them yet. And, once they're
9327 instantiated, they don't contain template parameters, so
9328 there's no point in looking at them then, either. */
9329 {
9330 tree parm;
9335 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9336 want walk_tree walking into them itself. */
9338 }
9341 {
9345 }
9362 /* Fall through. */
9374 /* Record template parameters such as `T' inside `TT<T>'. */
9376 /* Fall through. */
9388 /* A template template parameter is encountered. */
9392 /* Already substituted template template parameter */
9397 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9398 partial instantiation. */
9410 /* If there's no type, then this thing must be some expression
9411 involving template parameters. */
9433 }
9435 #undef WALK_SUBTREE
9437 /* We didn't find any template parameters we liked. */
9438 out:
9440 }
9442 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9443 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9444 call FN with the parameter and the DATA.
9445 If FN returns nonzero, the iteration is terminated, and
9446 for_each_template_parm returns 1. Otherwise, the iteration
9447 continues. If FN never returns a nonzero value, the value
9448 returned by for_each_template_parm is 0. If FN is NULL, it is
9449 considered to be the function which always returns 1.
9451 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9452 parameters that occur in non-deduced contexts. When false, only
9453 visits those template parameters that can be deduced. */
9455 static tree
9459 tree_fn_t any_fn)
9460 {
9462 tree result;
9464 /* Set up. */
9470 /* Walk the tree. (Conceptually, we would like to walk without
9471 duplicates, but for_each_template_parm_r recursively calls
9472 for_each_template_parm, so we would need to reorganize a fair
9473 bit to use walk_tree_without_duplicates, so we keep our own
9474 visited list.) */
9477 else
9480 for_each_template_parm_r,
9484 /* Clean up. */
9486 {
9489 }
9492 }
9494 /* Returns true if T depends on any template parameter. */
9496 int
9498 {
9528 else
9529 {
9532 }
9537 }
9539 /* Returns true iff current_function_decl is an incompletely instantiated
9540 template. Useful instead of processing_template_decl because the latter
9541 is set to 0 during instantiate_non_dependent_expr. */
9543 bool
9545 {
9554 }
9556 /* Returns true if T depends on any template parameter with level LEVEL. */
9558 bool
9560 {
9563 }
9565 /* Returns true if the signature of DECL depends on any template parameter from
9566 its enclosing class. */
9568 bool
9570 {
9580 template_parm_outer_level,
9590 }
9592 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9593 ill-formed translation unit, i.e. a variable or function that isn't
9594 usable in a constant expression. */
9598 {
9603 }
9605 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9606 neglectable and instantiated from within an erroneous instantiation. */
9608 static bool
9610 {
9621 }
9629 /* We're starting to instantiate D; record the template instantiation context
9630 for diagnostics and to restore it later. */
9632 bool
9634 {
9636 }
9638 /* We're starting to instantiate D; record the template instantiation context
9639 at LOC for diagnostics and to restore it later. */
9641 bool
9643 {
9647 {
9648 /* Tell error.c not to try to instantiate any templates. */
9651 "template instantiation depth exceeds maximum of %d"
9653 max_tinst_depth);
9655 }
9657 /* If the current instantiation caused problems, don't let it instantiate
9658 anything else. Do allow deduction substitution and decls usable in
9659 constant expressions. */
9663 /* When not -quiet, dump template instantiations other than functions, since
9664 announce_function will take care of those. */
9683 }
9685 /* We're done instantiating this template; return to the instantiation
9686 context. */
9688 void
9690 {
9691 /* Restore the filename and line number stashed away when we started
9692 this instantiation. */
9696 }
9698 /* We're instantiating a deferred template; restore the template
9699 instantiation context in which the instantiation was requested, which
9700 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9702 static tree
9704 {
9716 }
9718 /* Returns the TINST_LEVEL which gives the original instantiation
9719 context. */
9723 {
9729 }
9731 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9732 vector of template arguments, as for tsubst.
9734 Returns an appropriate tsubst'd friend declaration. */
9736 static tree
9738 {
9739 tree new_friend;
9744 /* This was a friend declared with an explicit template
9745 argument list, e.g.:
9747 friend void f<>(T);
9749 to indicate that f was a template instantiation, not a new
9750 function declaration. Now, we have to figure out what
9751 instantiation of what template. */
9752 {
9754 tree new_args;
9755 tree tmpl;
9758 /* Friend functions are looked up in the containing namespace scope.
9759 We must enter that scope, to avoid finding member functions of the
9760 current class with same name. */
9775 tsk_none);
9777 }
9781 /* The NEW_FRIEND will look like an instantiation, to the
9782 compiler, but is not an instantiation from the point of view of
9783 the language. For example, we might have had:
9785 template <class T> struct S {
9786 template <class U> friend void f(T, U);
9787 };
9789 Then, in S<int>, template <class U> void f(int, U) is not an
9790 instantiation of anything. */
9796 {
9800 }
9802 /* The mangled name for the NEW_FRIEND is incorrect. The function
9803 is not a template instantiation and should not be mangled like
9804 one. Therefore, we forget the mangling here; we'll recompute it
9805 later if we need it. */
9807 {
9810 }
9813 {
9814 tree old_decl;
9815 tree new_friend_template_info;
9816 tree new_friend_result_template_info;
9817 tree ns;
9820 /* We must save some information from NEW_FRIEND before calling
9821 duplicate decls since that function will free NEW_FRIEND if
9822 possible. */
9824 new_friend_is_defn =
9829 {
9830 /* This declaration is a `primary' template. */
9833 new_friend_result_template_info
9835 }
9836 else
9839 /* Inside pushdecl_namespace_level, we will push into the
9840 current namespace. However, the friend function should go
9841 into the namespace of the template. */
9851 {
9852 /* This new friend declaration matched an existing
9853 declaration. For example, given:
9855 template <class T> void f(T);
9856 template <class U> class C {
9857 template <class T> friend void f(T) {}
9858 };
9860 the friend declaration actually provides the definition
9861 of `f', once C has been instantiated for some type. So,
9862 old_decl will be the out-of-class template declaration,
9863 while new_friend is the in-class definition.
9865 But, if `f' was called before this point, the
9866 instantiation of `f' will have DECL_TI_ARGS corresponding
9867 to `T' but not to `U', references to which might appear
9868 in the definition of `f'. Previously, the most general
9869 template for an instantiation of `f' was the out-of-class
9870 version; now it is the in-class version. Therefore, we
9871 run through all specialization of `f', adding to their
9872 DECL_TI_ARGS appropriately. In particular, they need a
9873 new set of outer arguments, corresponding to the
9874 arguments for this class instantiation.
9876 The same situation can arise with something like this:
9878 friend void f(int);
9879 template <class T> class C {
9880 friend void f(T) {}
9881 };
9883 when `C<int>' is instantiated. Now, `f(int)' is defined
9884 in the class. */
9887 /* On the other hand, if the in-class declaration does
9888 *not* provide a definition, then we don't want to alter
9889 existing definitions. We can just leave everything
9890 alone. */
9891 ;
9892 else
9893 {
9897 /* Overwrite whatever template info was there before, if
9898 any, with the new template information pertaining to
9899 the declaration. */
9903 {
9904 /* We should have called reregister_specialization in
9905 duplicate_decls. */
9910 /* Instantiate it if the global has already been used. */
9914 }
9915 else
9916 {
9917 tree t;
9919 /* Indicate that the old function template is a partial
9920 instantiation. */
9928 /* Reassign any specializations already in the hash table
9929 to the new more general template, and add the
9930 additional template args. */
9934 {
9936 spec_entry elt;
9948 register_specialization
9951 }
9953 }
9954 }
9956 /* The information from NEW_FRIEND has been merged into OLD_DECL
9957 by duplicate_decls. */
9959 }
9960 }
9961 else
9962 {
9966 /* In the code
9967 template <class T> class C {
9968 template <class U> friend void C1<U>::f (); // case 1
9969 friend void C2<T>::f (); // case 2
9970 };
9971 we only need to make sure CONTEXT is a complete type for
9972 case 2. To distinguish between the two cases, we note that
9973 CONTEXT of case 1 remains dependent type after tsubst while
9974 this isn't true for case 2. */
9984 {
9986 /* do_friend adds the TEMPLATE_DECL for any member friend
9987 template even if it isn't a member template, i.e.
9988 template <class T> friend A<T>::f();
9989 Look through it in that case. */
9993 /* Check to see that the declaration is really present, and,
9994 possibly obtain an improved declaration. */
9999 }
10000 }
10003 }
10005 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10006 template arguments, as for tsubst.
10008 Returns an appropriate tsubst'd friend type or error_mark_node on
10009 failure. */
10011 static tree
10013 {
10014 tree tmpl;
10017 {
10020 }
10025 else
10033 {
10034 /* The friend template has already been declared. Just
10035 check to see that the declarations match, and install any new
10036 default parameters. We must tsubst the default parameters,
10037 of course. We only need the innermost template parameters
10038 because that is all that redeclare_class_template will look
10039 at. */
10042 {
10050 }
10051 }
10052 else
10053 {
10054 /* The friend template has not already been declared. In this
10055 case, the instantiation of the template class will cause the
10056 injection of this template into the namespace scope. */
10060 {
10061 /* The new TMPL is not an instantiation of anything, so we
10062 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10063 for the new type because that is supposed to be the
10064 corresponding template decl, i.e., TMPL. */
10071 /* It is hidden. */
10076 /* Inject this template into the enclosing namspace scope. */
10078 }
10079 }
10083 else
10087 }
10089 /* Returns zero if TYPE cannot be completed later due to circularity.
10090 Otherwise returns one. */
10092 static int
10094 {
10104 else
10106 }
10111 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10112 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10114 static tree
10117 {
10126 {
10133 clauses
10137 else
10139 }
10140 /* If the first attribute argument is an identifier, don't
10141 pass it through tsubst. Attributes like mode, format,
10142 cleanup and several target specific attributes expect it
10143 unmodified. */
10145 {
10146 tree chain
10151 }
10153 {
10154 /* An attribute pack expansion. */
10163 {
10167 }
10169 }
10170 else
10177 }
10179 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10180 unchanged or a new TREE_LIST chain. */
10182 static tree
10185 {
10190 {
10194 }
10198 {
10201 {
10204 {
10206 do
10211 }
10212 }
10214 }
10217 }
10219 /* Apply any attributes which had to be deferred until instantiation
10220 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10221 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10223 static void
10226 {
10228 tree t;
10235 {
10239 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10240 to our attributes parameter. */
10242 }
10243 else
10244 {
10246 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10247 lookup_template_class_1, and should be preserved. */
10251 }
10255 {
10259 }
10263 {
10268 {
10271 {
10275 do
10278 }
10279 else
10281 }
10284 }
10285 }
10287 /* Perform (or defer) access check for typedefs that were referenced
10288 from within the template TMPL code.
10289 This is a subroutine of instantiate_decl and instantiate_class_template.
10290 TMPL is the template to consider and TARGS is the list of arguments of
10291 that template. */
10293 static void
10295 {
10296 location_t saved_location;
10307 {
10319 /* Make access check error messages point to the location
10320 of the use of the typedef. */
10324 tf_warning_or_error);
10325 }
10327 }
10329 static tree
10331 {
10333 tree typedecl;
10334 tree pbinfo;
10335 tree base_list;
10337 tree fn_context;
10346 /* Figure out which template is being instantiated. */
10350 /* Mark the type as in the process of being defined. */
10353 /* Determine what specialization of the original template to
10354 instantiate. */
10359 {
10360 /* This TYPE is actually an instantiation of a partial
10361 specialization. We replace the innermost set of ARGS with
10362 the arguments appropriate for substitution. For example,
10363 given:
10365 template <class T> struct S {};
10366 template <class T> struct S<T*> {};
10368 and supposing that we are instantiating S<int*>, ARGS will
10369 presently be {int*} -- but we need {int}. */
10372 }
10373 else
10374 {
10377 }
10379 /* If the template we're instantiating is incomplete, then clearly
10380 there's nothing we can do. */
10382 {
10383 /* We can try again later. */
10386 }
10388 /* If we've recursively instantiated too many templates, stop. */
10392 /* We may be in the middle of deferred access check. Disable
10393 it now. */
10400 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10405 else
10406 {
10409 }
10410 /* Use #pragma pack from the template context. */
10416 /* Set the input location to the most specialized template definition.
10417 This is needed if tsubsting causes an error. */
10429 {
10432 /* Adjust visibility for template arguments. */
10434 }
10440 /* We should never instantiate a nested class before its enclosing
10441 class; we need to look up the nested class by name before we can
10442 instantiate it, and that lookup should instantiate the enclosing
10443 class. */
10449 {
10450 tree pbase_binfo;
10451 tree pushed_scope;
10454 /* We must enter the scope containing the type, as that is where
10455 the accessibility of types named in dependent bases are
10456 looked up from. */
10459 /* Substitute into each of the bases to determine the actual
10460 basetypes. */
10462 {
10463 tree base;
10469 {
10470 expanded_bases =
10477 }
10480 {
10482 /* Extract the already-expanded base class. */
10484 else
10485 /* Substitute to figure out the base class. */
10487 NULL_TREE);
10495 }
10496 }
10498 /* The list is now in reverse order; correct that. */
10503 }
10504 /* Now call xref_basetypes to set up all the base-class
10505 information. */
10513 /* Now that our base classes are set up, enter the scope of the
10514 class, so that name lookups into base classes, etc. will work
10515 correctly. This is precisely analogous to what we do in
10516 begin_class_definition when defining an ordinary non-template
10517 class, except we also need to push the enclosing classes. */
10520 /* Now members are processed in the order of declaration. */
10523 {
10527 {
10529 {
10531 /* A closure type for a lambda in an NSDMI or default argument.
10532 Ignore it; it will be regenerated when needed. */
10535 /* Build new CLASSTYPE_NESTED_UTDS. */
10537 tree newtag;
10543 /* If the member is a class template, then -- even after
10544 substitution -- there may be dependent types in the
10545 template argument list for the class. We increment
10546 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10547 that function will assume that no types are dependent
10548 when outside of a template. */
10558 {
10562 /* Unfortunately, lookup_template_class sets
10563 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10564 instantiation (i.e., for the type of a member
10565 template class nested within a template class.)
10566 This behavior is required for
10567 maybe_process_partial_specialization to work
10568 correctly, but is not accurate in this case;
10569 the TAG is not an instantiation of anything.
10570 (The corresponding TEMPLATE_DECL is an
10571 instantiation, but the TYPE is not.) */
10574 /* Now, we call pushtag to put this NEWTAG into the scope of
10575 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10576 pushtag calling push_template_decl. We don't have to do
10577 this for enums because it will already have been done in
10578 tsubst_enum. */
10582 }
10583 }
10585 {
10586 tree r;
10595 /* Instantiate members marked with attribute used. */
10601 }
10604 /* A closure type for a lambda in an NSDMI or default argument.
10606 else
10607 {
10608 /* Build new TYPE_FIELDS. */
10610 {
10611 tree condition;
10614 condition =
10624 }
10626 {
10627 tree r;
10631 /* The file and line for this declaration, to
10632 assist in error message reporting. Since we
10633 called push_tinst_level above, we don't need to
10634 restore these. */
10644 {
10645 /* A capture pack became multiple fields. */
10648 }
10651 {
10655 {
10656 /* In [temp.inst]:
10658 [t]he initialization (and any associated
10659 side-effects) of a static data member does
10660 not occur unless the static data member is
10661 itself used in a way that requires the
10662 definition of the static data member to
10663 exist.
10665 Therefore, we do not substitute into the
10666 initialized for the static data member here. */
10667 finish_static_data_member_decl
10673 /* Instantiate members marked with attribute used. */
10676 }
10678 {
10679 /* Determine whether R has a valid type and can be
10680 completed later. If R is invalid, then its type
10681 is replaced by error_mark_node. */
10687 {
10688 /* If R's type couldn't be completed and
10689 it isn't a flexible array member (whose
10690 type is incomplete by definition) give
10691 an error. */
10694 }
10695 }
10697 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10698 such a thing will already have been added to the field
10699 list by tsubst_enum in finish_member_declaration in the
10700 CLASSTYPE_NESTED_UTDS case above. */
10704 {
10707 }
10708 }
10709 }
10710 }
10711 }
10712 else
10713 {
10716 {
10717 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10723 {
10724 /* template <class T> friend class C; */
10727 }
10729 {
10730 /* template <class T> friend class C::D; */
10736 }
10739 {
10740 /* This could be either
10742 friend class T::C;
10744 when dependent_type_p is false or
10746 template <class U> friend class T::C;
10748 otherwise. */
10749 /* Bump processing_template_decl in case this is something like
10750 template <class T> friend struct A<T>::B. */
10757 }
10761 {
10762 /* friend class C;
10764 where C hasn't been declared yet. Let's lookup name
10765 from namespace scope directly, bypassing any name that
10766 come from dependent base class. */
10769 /* The call to xref_tag_from_type does injection for friend
10770 classes. */
10772 friend_type =
10776 }
10778 /* friend class C<T>; */
10781 /* Otherwise it's
10783 friend class C;
10785 where C is already declared or
10787 friend class C<int>;
10789 We don't have to do anything in these cases. */
10792 /* Trick make_friend_class into realizing that the friend
10793 we're adding is a template, not an ordinary class. It's
10794 important that we use make_friend_class since it will
10795 perform some error-checking and output cross-reference
10796 information. */
10804 }
10805 else
10806 {
10807 /* Build new DECL_FRIENDLIST. */
10808 tree r;
10810 /* The file and line for this declaration, to
10811 assist in error message reporting. Since we
10812 called push_tinst_level above, we don't need to
10813 restore these. */
10817 {
10820 }
10825 {
10828 }
10829 }
10830 }
10831 }
10834 {
10835 /* Restore these before substituting into the lambda capture
10836 initializers. */
10839 }
10842 {
10845 {
10851 {
10852 /* Set function_depth to avoid garbage collection. */
10856 }
10858 /* We need to instantiate the capture list from the template
10859 after we've instantiated the closure members, but before we
10860 consider adding the conversion op. Also keep any captures
10861 that may have been added during instantiation of the op(). */
10863 tree tmpl_cap
10872 }
10873 else
10875 }
10877 /* Set the file and line number information to whatever is given for
10878 the class itself. This puts error messages involving generated
10879 implicit functions at a predictable point, and the same point
10880 that would be used for non-template classes. */
10887 /* We don't instantiate default arguments for member functions. 14.7.1:
10889 The implicit instantiation of a class template specialization causes
10890 the implicit instantiation of the declarations, but not of the
10891 definitions or default arguments, of the class member functions,
10892 member classes, static data members and member templates.... */
10894 /* Some typedefs referenced from within the template code need to be access
10895 checked at template instantiation time, i.e now. These types were
10896 added to the template at parsing time. Let's get those and perform
10897 the access checks then. */
10907 /* The vtable for a template class can be emitted in any translation
10908 unit in which the class is instantiated. When there is no key
10909 method, however, finish_struct_1 will already have added TYPE to
10910 the keyed_classes. */
10915 }
10917 /* Wrapper for instantiate_class_template_1. */
10919 tree
10921 {
10922 tree ret;
10927 }
10929 static tree
10931 {
10932 tree r;
10938 else
10939 {
10946 }
10948 }
10950 /* Given a function parameter pack TMPL_PARM and some function parameters
10951 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10952 and set *SPEC_P to point at the next point in the list. */
10954 tree
10956 {
10957 /* Collect all of the extra "packed" parameters into an
10958 argument pack. */
10959 tree parmvec;
10969 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10973 {
10978 }
10980 /* Build the argument packs. */
10985 }
10987 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10988 NONTYPE_ARGUMENT_PACK. */
10990 static tree
10992 {
10994 }
10996 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10997 pack expansion with no extra args, 2 if it has extra args, or 0
10998 if it is not a pack expansion. */
11000 static int
11002 {
11008 /* A decl pack is itself an expansion. */
11015 }
11018 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11020 static tree
11022 {
11029 }
11031 /* This is a subroutine of tsubst_pack_expansion.
11033 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11034 mechanism to store the (non complete list of) arguments of the
11035 substitution and return a non substituted pack expansion, in order
11036 to wait for when we have enough arguments to really perform the
11037 substitution. */
11039 static bool
11043 {
11044 /* If one pack has an expansion and another pack has a normal
11045 argument or if one pack has an empty argument and an another
11046 one hasn't then tsubst_pack_expansion cannot perform the
11047 substitution and need to fall back on the
11048 PACK_EXPANSION_EXTRA mechanism. */
11056 {
11059 parm_pack;
11061 {
11066 /* We can't substitute a pack expansion with extra args into
11067 our pattern. */
11071 else
11073 }
11077 }
11079 }
11081 /* [temp.variadic]/6 says that:
11083 The instantiation of a pack expansion [...]
11084 produces a list E1,E2, ..., En, where N is the number of elements
11085 in the pack expansion parameters.
11087 This subroutine of tsubst_pack_expansion produces one of these Ei.
11089 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11090 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11091 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11092 INDEX is the index 'i' of the element Ei to produce. ARGS,
11093 COMPLAIN, and IN_DECL are the same parameters as for the
11094 tsubst_pack_expansion function.
11096 The function returns the resulting Ei upon successful completion,
11097 or error_mark_node.
11099 Note that this function possibly modifies the ARGS parameter, so
11100 it's the responsibility of the caller to restore it. */
11102 static tree
11104 tree parm_packs,
11106 tree args /* This parm gets
11108 tsubst_flags_t complain,
11109 tree in_decl)
11110 {
11111 tree t;
11114 /* For each parameter pack, change the substitution of the parameter
11115 pack to the ith argument in its argument pack, then expand the
11116 pattern. */
11118 {
11123 ith_elem_is_expansion |=
11126 /* Select the Ith argument from the pack. */
11129 {
11131 {
11136 }
11137 else
11139 }
11140 else
11141 {
11146 {
11148 /* Update the corresponding argument. */
11150 }
11151 else
11152 /* Re-use the ARGUMENT_PACK_SELECT. */
11154 }
11156 }
11158 /* Substitute into the PATTERN with the (possibly altered)
11159 arguments. */
11161 /* Expanding a fixed parameter pack from
11162 coerce_template_parameter_pack. */
11167 {
11170 else
11173 }
11177 else
11180 /* If the Ith argument pack element is a pack expansion, then
11181 the Ith element resulting from the substituting is going to
11182 be a pack expansion as well. */
11187 }
11189 /* When the unexpanded parameter pack in a fold expression expands to an empty
11190 sequence, the value of the expression is as follows; the program is
11191 ill-formed if the operator is not listed in this table.
11193 && true
11194 || false
11195 , void() */
11197 tree
11199 {
11203 {
11212 }
11218 }
11220 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11221 form an expression that combines the two terms using the
11222 operator of T. */
11224 static tree
11226 {
11230 // Handle compound assignment operators.
11235 {
11245 complain);
11246 }
11247 }
11249 /* Substitute ARGS into the pack of a fold expression T. */
11253 {
11255 }
11257 /* Substitute ARGS into the pack of a fold expression T. */
11261 {
11263 }
11265 /* Expand a PACK of arguments into a grouped as left fold.
11266 Given a pack containing elements A0, A1, ..., An and an
11267 operator @, this builds the expression:
11269 ((A0 @ A1) @ A2) ... @ An
11271 Note that PACK must not be empty.
11273 The operator is defined by the original fold expression T. */
11275 static tree
11277 {
11280 {
11283 }
11285 }
11287 /* Substitute into a unary left fold expression. */
11289 static tree
11291 tree in_decl)
11292 {
11297 {
11301 }
11304 else
11306 }
11308 /* Substitute into a binary left fold expression.
11310 Do ths by building a single (non-empty) vector of argumnts and
11311 building the expression from those elements. */
11313 static tree
11315 tree in_decl)
11316 {
11325 {
11330 }
11338 }
11340 /* Expand a PACK of arguments into a grouped as right fold.
11341 Given a pack containing elementns A0, A1, ..., and an
11342 operator @, this builds the expression:
11344 A0@ ... (An-2 @ (An-1 @ An))
11346 Note that PACK must not be empty.
11348 The operator is defined by the original fold expression T. */
11350 tree
11352 {
11353 // Build the expression.
11357 {
11360 }
11362 }
11364 /* Substitute into a unary right fold expression. */
11366 static tree
11368 tree in_decl)
11369 {
11374 {
11378 }
11381 else
11383 }
11385 /* Substitute into a binary right fold expression.
11387 Do ths by building a single (non-empty) vector of arguments and
11388 building the expression from those elements. */
11390 static tree
11392 tree in_decl)
11393 {
11402 {
11407 }
11416 }
11418 /* Walk through the pattern of a pack expansion, adding everything in
11419 local_specializations to a list. */
11421 static tree
11423 {
11426 {
11428 {
11429 /* Pull out the actual PARM_DECL for the partial instantiation. */
11434 }
11436 }
11438 }
11439 static tree
11441 {
11445 }
11447 /* Substitute ARGS into T, which is an pack expansion
11448 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11449 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11450 (if only a partial substitution could be performed) or
11451 ERROR_MARK_NODE if there was an error. */
11452 tree
11454 tree in_decl)
11455 {
11456 tree pattern;
11461 tree result;
11469 /* Add in any args remembered from an earlier partial instantiation. */
11472 {
11474 {
11475 /* The partial instantiation involved local declarations collected in
11476 extract_local_specs; map from the general template to our local
11477 context. */
11482 }
11485 }
11490 /* Determine the argument packs that will instantiate the parameter
11491 packs used in the expansion expression. While we're at it,
11492 compute the number of arguments to be expanded and make sure it
11493 is consistent. */
11496 {
11503 {
11508 else
11511 }
11513 {
11514 /* ??? Support use in other patterns. */
11518 }
11520 {
11521 /* We know we have correct local_specializations if this
11522 expansion is at function scope, or if we're dealing with a
11523 local parameter in a requires expression; for the latter,
11524 tsubst_requires_expr set it up appropriately. */
11527 else
11528 /* We can't rely on local_specializations for a parameter
11529 name used later in a function declaration (such as in a
11530 late-specified return type). Even if it exists, it might
11531 have the wrong value for a recursive call. */
11535 {
11536 /* This parameter pack was used in an unevaluated context. Just
11537 make a dummy decl, since it's only used for its type. */
11540 /* Partial instantiation of the parm_pack, we can't build
11541 up an argument pack yet. */
11543 else
11545 }
11547 /* This argument pack isn't fully instantiated yet. We set this
11548 flag rather than clear arg_pack because we do want to do the
11549 optimization below, and we don't want to substitute directly
11550 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
11551 where it isn't expected). */
11553 }
11556 else
11557 {
11563 }
11570 /* This can only happen if we forget to expand an argument
11571 pack somewhere else. Just return an error, silently. */
11572 {
11576 }
11579 {
11583 /* Don't bother trying to do a partial substitution with
11584 incomplete packs; we'll try again after deduction. */
11592 {
11597 pattern);
11598 else
11600 pattern);
11602 }
11604 /* Keep track of the parameter packs and their corresponding
11605 argument packs. */
11608 }
11609 else
11610 {
11611 /* We can't substitute for this parameter pack. We use a flag as
11612 well as the missing_level counter because function parameter
11613 packs don't have a level. */
11616 }
11617 }
11619 /* If the expansion is just T..., return the matching argument pack, unless
11620 we need to call convert_from_reference on all the elements. This is an
11621 important optimization; see c++/68422. */
11624 {
11627 /* If the argument pack is a single pack expansion, pull it out. */
11632 /* Types need no adjustment, nor does sizeof..., and if we still have
11633 some pack expansion args we won't do anything yet. */
11638 /* Also optimize expression pack expansions if we can tell that the
11639 elements won't have reference type. */
11645 /* Otherwise use the normal path so we get convert_from_reference. */
11646 }
11648 /* We cannot expand this expansion expression, because we don't have
11649 all of the argument packs we need. */
11652 {
11653 /* We got some full packs, but we can't substitute them in until we
11654 have values for all the packs. So remember these until then. */
11663 }
11665 {
11666 /* There were no real arguments, we're just replacing a parameter
11667 pack with another version of itself. Substitute into the
11668 pattern and return a PACK_EXPANSION_*. The caller will need to
11669 deal with that. */
11673 else
11677 }
11682 {
11683 /* We're in a late-specified return type, so create our own local
11684 specializations map; the current map is either NULL or (in the
11685 case of recursive unification) might have bindings that we don't
11686 want to use or alter. */
11689 }
11691 /* For each argument in each argument pack, substitute into the
11692 pattern. */
11696 {
11698 i,
11700 in_decl);
11703 {
11706 }
11707 }
11709 /* Update ARGS to restore the substitution from parameter packs to
11710 their argument packs. */
11712 {
11718 else
11719 {
11727 /* Update the corresponding argument. */
11731 else
11733 }
11734 }
11737 {
11740 }
11742 /* If the dependent pack arguments were such that we end up with only a
11743 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11749 }
11751 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11752 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11753 parameter packs; all parms generated from a function parameter pack will
11754 have the same DECL_PARM_INDEX. */
11756 tree
11758 {
11760 tree patparm;
11763 {
11769 }
11770 else
11771 {
11776 }
11779 }
11781 /* Make an argument pack out of the TREE_VEC VEC. */
11783 static tree
11785 {
11786 tree pack;
11790 else
11791 {
11794 }
11797 }
11799 /* Return an exact copy of template args T that can be modified
11800 independently. */
11802 static tree
11804 {
11812 {
11817 }
11823 }
11825 /* Substitute ARGS into the vector or list of template arguments T. */
11827 static tree
11829 {
11841 {
11843 tree new_arg;
11848 {
11849 /* Substitute into an expansion expression. */
11853 /* Add to the expanded length adjustment the number of
11854 expanded arguments. We subtract one from this
11855 measurement, because the argument pack expression
11856 itself is already counted as 1 in
11857 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11858 the argument pack is empty. */
11860 }
11862 {
11863 /* Substitute into each of the arguments. */
11872 else
11877 }
11878 else
11887 }
11892 /* Make space for the expanded arguments coming from template
11893 argument packs. */
11895 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11896 arguments for a member template.
11897 In that case each TREE_VEC in ORIG_T represents a level of template
11898 arguments, and ORIG_T won't carry any non defaulted argument count.
11899 It will rather be the nested TREE_VECs that will carry one.
11900 In other words, ORIG_T carries a non defaulted argument count only
11901 if it doesn't contain any nested TREE_VEC. */
11903 {
11907 }
11909 {
11913 {
11916 /* Now expand the template argument pack "in place". */
11919 }
11920 else
11921 {
11923 out++;
11924 }
11925 }
11928 }
11930 /* Substitute ARGS into one level PARMS of template parameters. */
11932 static tree
11934 {
11941 {
11949 }
11952 }
11954 /* Return the result of substituting ARGS into the template parameters
11955 given by PARMS. If there are m levels of ARGS and m + n levels of
11956 PARMS, then the result will contain n levels of PARMS. For
11957 example, if PARMS is `template <class T> template <class U>
11958 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11959 result will be `template <int*, double, class V>'. */
11961 static tree
11963 {
11967 /* When substituting into a template, we must set
11968 PROCESSING_TEMPLATE_DECL as the template parameters may be
11969 dependent if they are based on one-another, and the dependency
11970 predicates are short-circuit outside of templates. */
11977 {
11984 }
11989 }
11991 /* Return the result of substituting ARGS into one template parameter
11992 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11993 parameter and which TREE_PURPOSE is the default argument of the
11994 template parameter. */
11996 static tree
11998 {
12019 }
12021 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12022 type T. If T is not an aggregate or enumeration type, it is
12023 handled as if by tsubst. IN_DECL is as for tsubst. If
12024 ENTERING_SCOPE is nonzero, T is the context for a template which
12025 we are presently tsubst'ing. Return the substituted value. */
12027 static tree
12029 tree args,
12030 tsubst_flags_t complain,
12031 tree in_decl,
12033 {
12038 {
12043 /* Fall through. */
12047 {
12048 tree argvec;
12049 tree context;
12050 tree r;
12054 /* In "sizeof(X<I>)" we need to evaluate "I". */
12060 /* First, determine the context for the type we are looking
12061 up. */
12064 {
12067 /* If context is a nested class inside a class template,
12068 it may still need to be instantiated (c++/33959). */
12070 }
12072 /* Then, figure out what arguments are appropriate for the
12073 type we are trying to find. For example, given:
12075 template <class T> struct S;
12076 template <class T, class U> void f(T, U) { S<U> su; }
12078 and supposing that we are instantiating f<int, double>,
12079 then our ARGS will be {int, double}, but, when looking up
12080 S we only want {double}. */
12085 else
12086 {
12090 }
12096 }
12097 else
12098 /* This is not a template type, so there's nothing to do. */
12103 }
12104 }
12108 /* Substitute into the default argument ARG (a default argument for
12109 FN), which has the indicated TYPE. */
12111 tree
12113 tsubst_flags_t complain)
12114 {
12119 /* This can happen in invalid code. */
12134 /* This default argument came from a template. Instantiate the
12135 default argument here, not in tsubst. In the case of
12136 something like:
12138 template <class T>
12139 struct S {
12140 static T t();
12141 void f(T = t());
12142 };
12144 we must be careful to do name lookup in the scope of S<T>,
12145 rather than in the current class. */
12147 /* The "this" pointer is not valid in a default argument. */
12149 {
12154 }
12159 /* The default argument expression may cause implicitly defined
12160 member functions to be synthesized, which will result in garbage
12161 collection. We must treat this situation as if we were within
12162 the body of function so as to avoid collecting live data on the
12163 stack. */
12173 /* Restore the "this" pointer. */
12175 {
12178 }
12185 /* Make sure the default argument is reasonable. */
12191 {
12195 }
12198 }
12200 /* Substitute into all the default arguments for FN. */
12202 static void
12204 {
12205 tree arg;
12206 tree tmpl_args;
12210 /* If this function is not yet instantiated, we certainly don't need
12211 its default arguments. */
12214 /* Don't do this again for clones. */
12220 arg;
12226 complain);
12227 }
12229 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12231 static tree
12233 tree lambda_fntype)
12234 {
12239 /* Nobody should be tsubst'ing into non-template functions. */
12243 {
12244 /* If T is not dependent, just return it. */
12248 /* Calculate the most general template of which R is a
12249 specialization. */
12252 /* We're substituting a lambda function under tsubst_lambda_expr but not
12253 directly from it; find the matching function we're already inside.
12254 But don't do this if T is a generic lambda with a single level of
12255 template parms, as in that case we're doing a normal instantiation. */
12261 /* Calculate the complete set of arguments used to
12262 specialize R. */
12264 (DECL_TEMPLATE_RESULT
12270 /* Check to see if we already have this specialization. */
12272 {
12276 }
12278 /* We can see more levels of arguments than parameters if
12279 there was a specialization of a member template, like
12280 this:
12282 template <class T> struct S { template <class U> void f(); }
12283 template <> template <class U> void S<int>::f(U);
12285 Here, we'll be substituting into the specialization,
12286 because that's where we can find the code we actually
12287 want to generate, but we'll have enough arguments for
12288 the most general template.
12290 We also deal with the peculiar case:
12292 template <class T> struct S {
12293 template <class U> friend void f();
12294 };
12295 template <class U> void f() {}
12296 template S<int>;
12297 template void f<double>();
12299 Here, the ARGS for the instantiation of will be {int,
12300 double}. But, we only need as many ARGS as there are
12301 levels of template parameters in CODE_PATTERN. We are
12302 careful not to get fooled into reducing the ARGS in
12303 situations like:
12305 template <class T> struct S { template <class U> void f(U); }
12306 template <class T> template <> void S<T>::f(int) {}
12308 which we can spot because the pattern will be a
12309 specialization in this case. */
12316 }
12317 else
12318 {
12319 /* This special case arises when we have something like this:
12321 template <class T> struct S {
12322 friend void f<int>(int, double);
12323 };
12325 Here, the DECL_TI_TEMPLATE for the friend declaration
12326 will be an IDENTIFIER_NODE. We are being called from
12327 tsubst_friend_function, and we want only to create a
12328 new decl (R) with appropriate types so that we can call
12329 determine_specialization. */
12332 }
12349 /* If we hit excessive deduction depth, the type is bogus even if
12350 it isn't error_mark_node, so don't build a decl. */
12354 /* We do NOT check for matching decls pushed separately at this
12355 point, as they may not represent instantiations of this
12356 template, and in any case are considered separate under the
12357 discrete model. */
12361 /* Clear out the mangled name and RTL for the instantiation. */
12364 /* Leave DECL_INITIAL set on deleted instantiations. */
12369 /* OpenMP UDRs have the only argument a reference to the declared
12370 type. We want to diagnose if the declared type is a reference,
12371 which is invalid, but as references to references are usually
12372 quietly merged, diagnose it here. */
12374 {
12375 tree argtype
12380 "reference type %qT in "
12384 argtype);
12385 }
12388 /* Type-conversion operator. Reconstruct the name, in
12389 case it's the name of one of the template's parameters. */
12399 {
12403 }
12410 /* If this is an instantiation of a function with internal
12411 linkage, we already know what object file linkage will be
12412 assigned to the instantiation. */
12421 /* We'll re-clone as appropriate in instantiate_template. */
12424 /* If we aren't complaining now, return on error before we register
12425 the specialization so that we'll complain eventually. */
12431 /* When instantiating a constrained member, substitute
12432 into the constraints to create a new constraint. */
12435 {
12438 }
12440 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12441 this in the special friend case mentioned above where
12442 GEN_TMPL is NULL. */
12444 {
12449 tree new_r
12452 /* We instantiated this while substituting into
12453 the type earlier (template/friend54.C). */
12456 /* We're not supposed to instantiate default arguments
12457 until they are called, for a template. But, for a
12458 declaration like:
12460 template <class T> void f ()
12461 { extern void g(int i = T()); }
12463 we should do the substitution when the template is
12464 instantiated. We handle the member function case in
12465 instantiate_class_template since the default arguments
12466 might refer to other members of the class. */
12471 }
12472 else
12475 /* Copy the list of befriending classes. */
12479 {
12483 }
12486 {
12490 /* If this is an instantiation of a member template, clone it.
12491 If it isn't, that'll be handled by
12492 clone_constructors_and_destructors. */
12495 }
12506 /* Possibly limit visibility based on template args. */
12509 {
12513 }
12522 }
12524 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12526 static tree
12528 tree lambda_fntype)
12529 {
12530 /* We can get here when processing a member function template,
12531 member class template, or template template parameter. */
12534 tree spec;
12535 tree tmpl_args;
12536 tree full_args;
12537 tree r;
12541 {
12542 /* Template template parameter is treated here. */
12546 /* If we get a real template back, return it. This can happen in
12547 the context of most_specialized_partial_spec. */
12550 else
12551 /* The new TEMPLATE_DECL was built in
12552 reduce_template_parm_level. */
12555 }
12558 {
12559 /* We might already have an instance of this template.
12560 The ARGS are for the surrounding class type, so the
12561 full args contain the tsubst'd args for the context,
12562 plus the innermost args from the template decl. */
12566 /* Because this is a template, the arguments will still be
12567 dependent, even after substitution. If
12568 PROCESSING_TEMPLATE_DECL is not set, the dependency
12569 predicates will short-circuit. */
12577 /* If this is a default template template argument,
12578 tsubst might not have changed anything. */
12586 }
12588 /* Make a new template decl. It will be similar to the
12589 original, but will record the current template arguments.
12590 We also create a new function declaration, which is just
12591 like the old one, but points to this new template, rather
12592 than the old one. */
12597 // Build new template info linking to the original template decl.
12599 {
12602 }
12603 else
12606 /* The template parameters for this new template are all the
12607 template parameters for the old template, except the
12608 outermost level of parameters. */
12611 complain);
12615 {
12616 tree new_type;
12624 /* For a partial specialization, we need to keep pointing to
12625 the primary template. */
12631 }
12632 else
12633 {
12634 tree new_decl;
12638 else
12648 {
12651 }
12652 else
12653 {
12656 }
12657 }
12667 /* Record this non-type partial instantiation. */
12673 }
12675 /* True if FN is the op() for a lambda in an uninstantiated template. */
12677 bool
12679 {
12684 }
12686 /* We're instantiating a variable from template function TCTX. Return the
12687 corresponding current enclosing scope. This gets complicated because lambda
12688 functions in templates are regenerated rather than instantiated, but generic
12689 lambda functions are subsequently instantiated. */
12691 static tree
12693 {
12702 {
12715 }
12717 }
12719 /* Substitute the ARGS into the T, which is a _DECL. Return the
12720 result of the substitution. Issue error and warning messages under
12721 control of COMPLAIN. */
12723 static tree
12725 {
12726 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12727 location_t saved_loc;
12732 /* Set the filename and linenumber to improve error-reporting. */
12737 {
12747 {
12755 {
12756 /* If there is a local specialization that isn't a
12757 parameter pack, it means that we're doing a "simple"
12758 substitution from inside tsubst_pack_expansion. Just
12759 return the local specialization (which will be a single
12760 parm). */
12767 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12768 the parameters in this function parameter pack. */
12772 {
12775 /* Zero-length parameter packs are boring. Just substitute
12776 into the chain. */
12780 }
12781 else
12782 {
12783 /* All we did was update the type. Make a note of that. */
12786 }
12787 }
12789 /* Loop through all of the parameters we'll build. When T is
12790 a function parameter pack, LEN is the number of expanded
12791 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12794 {
12801 /* We're on the Ith parameter of the function parameter
12802 pack. */
12803 {
12804 /* Get the Ith type. */
12807 /* Rename the parameter to include the index. */
12810 }
12812 /* We're dealing with a normal parameter. */
12820 {
12823 else
12826 }
12836 /* Keep track of the first new parameter we
12837 generate. That's what will be returned to the
12838 caller. */
12842 /* Build a proper chain of parameters when substituting
12843 into a function parameter pack. */
12846 }
12848 /* If cp_unevaluated_operand is set, we're just looking for a
12849 single dummy parameter, so don't keep going. */
12854 /* FIRST_R contains the start of the chain we've built. */
12856 }
12860 {
12867 {
12868 /* This field is a lambda capture pack. Return a TREE_VEC of
12869 the expanded fields to instantiate_class_template_1 and
12870 store them in the specializations hash table as a
12871 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12875 {
12878 }
12879 else
12880 {
12881 /* All we did was update the type. Make a note of that. */
12884 }
12885 }
12888 {
12891 {
12895 }
12905 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
12906 number of bits. */
12912 {
12913 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12914 NSDMI in perform_member_init. Still set DECL_INITIAL
12915 so that we know there is one. */
12920 }
12921 /* We don't have to set DECL_CONTEXT here; it is set by
12922 finish_member_declaration. */
12930 }
12933 {
12938 }
12939 }
12943 /* We reach here only for member using decls. We also need to check
12944 uses_template_parms because DECL_DEPENDENT_P is not set for a
12945 using-declaration that designates a member of the current
12946 instantiation (c++/53549). */
12949 {
12953 {
12958 {
12962 {
12965 }
12966 else
12967 {
12970 }
12972 }
12973 }
12974 else
12975 {
12981 else
12982 {
12985 }
12986 }
12987 }
12988 else
12989 {
12992 }
12997 {
13000 tree spec;
13002 tree ctx;
13011 {
13012 /* If this is the canonical decl, we don't have to
13013 mess with instantiations, and often we can't (for
13014 typename, template type parms and such). Note that
13015 TYPE_NAME is not correct for the above test if
13016 we've copied the type for a typedef. */
13022 }
13024 /* Check to see if we already have the specialization we
13025 need. */
13028 {
13029 /* T is a static data member or namespace-scope entity.
13030 We have to substitute into namespace-scope variables
13031 (not just variable templates) because of cases like:
13033 template <class T> void f() { extern T t; }
13035 where the entity referenced is not known until
13036 instantiation time. */
13040 {
13042 complain,
13044 /* If CTX is unchanged, then T is in fact the
13045 specialization we want. That situation occurs when
13046 referencing a static data member within in its own
13047 class. We can use pointer equality, rather than
13048 same_type_p, because DECL_CONTEXT is always
13049 canonical... */
13051 /* ... unless T is a member template; in which
13052 case our caller can be willing to create a
13053 specialization of that template represented
13054 by T. */
13058 }
13061 {
13066 argvec = (coerce_innermost_template_parms
13074 }
13075 }
13076 else
13077 {
13078 /* A local variable. */
13080 /* Subsequent calls to pushdecl will fill this in. */
13082 /* Unless this is a reference to a static variable from an
13083 enclosing function, in which case we need to fill it in now. */
13085 {
13089 }
13091 }
13092 /* If we already have the specialization we need, there is
13093 nothing more to do. */
13095 {
13098 }
13100 /* Create a new node for the specialization we need. */
13103 {
13106 else
13114 {
13115 /* Mask off any template args past the variable's context so we
13116 don't replace the auto with an unrelated argument. */
13120 /* This should never happen with the new lambda instantiation
13121 model, but keep the handling just in case. */
13124 }
13126 }
13128 {
13129 /* Even if the original location is out of scope, the
13130 newly substituted one is not. */
13137 {
13138 /* It may seem that this case cannot occur, since:
13140 typedef void f();
13141 void g() { f x; }
13143 declares a function, not a variable. However:
13145 typedef void f();
13146 template <typename T> void g() { T t; }
13147 template void g<f>();
13149 is an attempt to declare a variable with function
13150 type. */
13152 /* R is not yet sufficiently initialized, so we
13153 just use its name. */
13156 }
13158 /* Wait until cp_finish_decl to set this again, to handle
13159 circular dependency (template/instantiate6.C). */
13164 {
13169 {
13172 }
13174 }
13178 }
13184 /* Clear out the mangled name and RTL for the instantiation. */
13188 /* The initializer must not be expanded until it is required;
13189 see [temp.inst]. */
13193 {
13199 /* Possibly limit visibility based on template args. */
13202 {
13206 }
13208 }
13211 {
13212 /* A static data member declaration is always marked
13213 external when it is declared in-class, even if an
13214 initializer is present. We mimic the non-template
13215 processing here. */
13223 }
13224 else
13225 {
13230 }
13238 /* Preserve a typedef that names a type. */
13240 {
13244 /* An alias template specialization can be dependent
13245 even if its underlying type is not. */
13247 }
13250 }
13255 }
13256 #undef RETURN
13258 out:
13259 /* Restore the file and line information. */
13263 }
13265 /* Substitute into the ARG_TYPES of a function type.
13266 If END is a TREE_CHAIN, leave it and any following types
13267 un-substituted. */
13269 static tree
13271 tree args,
13272 tree end,
13273 tsubst_flags_t complain,
13274 tree in_decl)
13275 {
13276 tree remaining_arg_types;
13280 tree default_arg;
13291 {
13292 /* For a pack expansion, perform substitution on the
13293 entire expression. Later on, we'll handle the arguments
13294 one-by-one. */
13299 /* So that we'll spin through the parameters, one by one. */
13301 else
13302 {
13303 /* We only partially substituted into the parameter
13304 pack. Our type is TYPE_PACK_EXPANSION. */
13307 }
13308 }
13321 {
13323 {
13327 }
13329 }
13330 /* DR 657. */
13334 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13335 top-level qualifiers as required. */
13338 /* We do not substitute into default arguments here. The standard
13339 mandates that they be instantiated only when needed, which is
13340 done in build_over_call. */
13343 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13344 since the new op() won't have any associated template arguments for us
13345 to refer to later. */
13351 {
13352 /* We've instantiated a template before its default arguments
13353 have been parsed. This can happen for a nested template
13354 class, and is not an error unless we require the default
13355 argument in a call of this function. */
13356 remaining_arg_types =
13359 }
13360 else
13361 remaining_arg_types =
13363 }
13366 }
13368 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13369 *not* handle the exception-specification for FNTYPE, because the
13370 initial substitution of explicitly provided template parameters
13371 during argument deduction forbids substitution into the
13372 exception-specification:
13374 [temp.deduct]
13376 All references in the function type of the function template to the
13377 corresponding template parameters are replaced by the specified tem-
13378 plate argument values. If a substitution in a template parameter or
13379 in the function type of the function template results in an invalid
13380 type, type deduction fails. [Note: The equivalent substitution in
13381 exception specifications is done only when the function is instanti-
13382 ated, at which point a program is ill-formed if the substitution
13383 results in an invalid type.] */
13385 static tree
13387 tree args,
13388 tsubst_flags_t complain,
13389 tree in_decl)
13390 {
13391 tree return_type;
13393 tree fntype;
13395 /* The TYPE_CONTEXT is not used for function/method types. */
13398 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13399 failure. */
13403 {
13404 /* Substitute the argument types. */
13416 {
13417 /* DR 1207: 'this' is in scope in the trailing return type. */
13419 }
13421 /* Substitute the return type. */
13425 {
13428 }
13429 }
13430 else
13431 /* Substitute the return type. */
13436 /* DR 486 clarifies that creation of a function type with an
13437 invalid return type is a deduction failure. */
13440 {
13442 {
13445 else
13447 }
13449 }
13450 /* And DR 657. */
13455 {
13456 /* Substitute the argument types. */
13461 }
13463 /* Construct a new type node and return it. */
13465 {
13470 }
13471 else
13472 {
13474 /* Don't pick up extra function qualifiers from the basetype. */
13477 {
13478 /* [temp.deduct]
13480 Type deduction may fail for any of the following
13481 reasons:
13483 -- Attempting to create "pointer to member of T" when T
13484 is not a class type. */
13487 r);
13489 }
13494 }
13501 }
13503 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13504 ARGS into that specification, and return the substituted
13505 specification. If there is no specification, return NULL_TREE. */
13507 static tree
13509 tree args,
13510 tsubst_flags_t complain,
13511 tree in_decl,
13513 {
13514 tree specs;
13515 tree new_specs;
13520 {
13521 /* A noexcept-specifier. */
13526 {
13527 /* Defer instantiation of noexcept-specifiers to avoid
13528 excessive instantiations (c++/49107). */
13531 {
13532 /* We already partially instantiated this member template,
13533 so combine the new args with the old. */
13538 }
13539 else
13540 {
13543 }
13544 }
13545 else
13546 new_specs = tsubst_copy_and_build
13550 }
13552 {
13555 else
13557 {
13558 tree spec;
13563 {
13564 /* Expand the pack expansion type. */
13567 in_decl);
13573 else
13574 {
13575 /* We're substituting into a member template, so
13576 we got a TYPE_PACK_EXPANSION back. Add that
13577 expansion and move on. */
13581 expanded_specs,
13582 complain);
13585 }
13586 }
13589 {
13592 else
13597 complain);
13598 }
13601 }
13602 }
13604 }
13606 /* Take the tree structure T and replace template parameters used
13607 therein with the argument vector ARGS. IN_DECL is an associated
13608 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13609 Issue error and warning messages under control of COMPLAIN. Note
13610 that we must be relatively non-tolerant of extensions here, in
13611 order to preserve conformance; if we allow substitutions that
13612 should not be allowed, we may allow argument deductions that should
13613 not succeed, and therefore report ambiguous overload situations
13614 where there are none. In theory, we could allow the substitution,
13615 but indicate that it should have failed, and allow our caller to
13616 make sure that the right thing happens, but we don't try to do this
13617 yet.
13619 This function is used for dealing with types, decls and the like;
13620 for expressions, use tsubst_expr or tsubst_copy. */
13622 tree
13624 {
13647 else
13652 /* Reuse typedefs. We need to do this to handle dependent attributes,
13653 such as attribute aligned. */
13656 {
13660 {
13661 /* DECL represents an alias template and we want to
13662 instantiate it. */
13666 }
13670 {
13674 }
13679 else
13680 /* The typedef is from a non-template context. */
13684 {
13686 r = cp_build_qualified_type_real
13690 }
13691 else
13692 {
13693 /* We don't have an instantiation yet, so drop the typedef. */
13698 }
13699 }
13716 {
13742 {
13748 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13749 needed. */
13755 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13756 with TREE_SIDE_EFFECTS that indicates this is not an integral
13757 constant expression. */
13760 {
13763 }
13766 }
13772 {
13778 /* Early in template argument deduction substitution, we don't
13779 want to reduce the level of 'auto', or it will be confused
13780 with a normal template parm in subsequent deduction. */
13792 {
13796 {
13797 /* See through ARGUMENT_PACK_SELECT arguments. */
13799 /* If the selected argument is an expansion E, that most
13800 likely means we were called from
13801 gen_elem_of_pack_expansion_instantiation during the
13802 substituting of pack an argument pack (which Ith
13803 element is a pack expansion, where I is
13804 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13805 In this case, the Ith element resulting from this
13806 substituting is going to be a pack expansion, which
13807 pattern is the pattern of E. Let's return the
13808 pattern of E, and
13809 gen_elem_of_pack_expansion_instantiation will
13810 build the resulting pack expansion from it. */
13812 {
13813 /* Make sure we aren't throwing away arg info. */
13816 }
13817 }
13818 }
13823 {
13825 /* If ARG is an argument pack, we don't actually want to
13826 perform a substitution here, because substitutions
13827 for argument packs are only done
13828 element-by-element. We can get to this point when
13829 substituting the type of a non-type template
13830 parameter pack, when that type actually contains
13831 template parameter packs from an outer template, e.g.,
13833 template<typename... Types> struct A {
13834 template<Types... Values> struct B { };
13835 }; */
13839 {
13845 return cp_build_qualified_type_real
13847 }
13849 {
13850 /* We are processing a type constructed from a
13851 template template parameter. */
13862 /* Consider this code:
13864 template <template <class> class Template>
13865 struct Internal {
13866 template <class Arg> using Bind = Template<Arg>;
13867 };
13869 template <template <class> class Template, class Arg>
13870 using Instantiate = Template<Arg>; //#0
13872 template <template <class> class Template,
13873 class Argument>
13874 using Bind =
13875 Instantiate<Internal<Template>::template Bind,
13876 Argument>; //#1
13878 When #1 is parsed, the
13879 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13880 parameter `Template' in #0 matches the
13881 UNBOUND_CLASS_TEMPLATE representing the argument
13882 `Internal<Template>::template Bind'; We then want
13883 to assemble the type `Bind<Argument>' that can't
13884 be fully created right now, because
13885 `Internal<Template>' not being complete, the Bind
13886 template cannot be looked up in that context. So
13887 we need to "store" `Bind<Argument>' for later
13888 when the context of Bind becomes complete. Let's
13889 store that in a TYPENAME_TYPE. */
13893 argvec),
13894 typename_type,
13895 complain);
13897 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13898 are resolving nested-types in the signature of a
13899 member function templates. Otherwise ARG is a
13900 TEMPLATE_DECL and is the real template to be
13901 instantiated. */
13909 complain);
13910 return cp_build_qualified_type_real
13912 }
13915 else
13916 /* TEMPLATE_PARM_INDEX. */
13918 }
13921 /* This can happen during the attempted tsubst'ing in
13922 unify. This means that we don't yet have any information
13923 about the template parameter in question. */
13926 /* If we get here, we must have been looking at a parm for a
13927 more deeply nested template. Make a new version of this
13928 template parameter, but with a lower level. */
13930 {
13935 {
13937 r = cp_build_qualified_type_real
13941 }
13948 /* Break infinite recursion when substituting the constraints
13950 else
13951 {
13962 {
13963 /* Propagate constraints on placeholders. */
13968 {
13972 }
13973 }
13976 /* We have reduced the level of the template
13977 template parameter, but not the levels of its
13978 template parameters, so canonical_type_parameter
13979 will not be able to find the canonical template
13980 template parameter for this level. Thus, we
13981 require structural equality checking to compare
13982 TEMPLATE_TEMPLATE_PARMs. */
13986 else
13990 {
13992 /* We might need to substitute into the types of non-type
13993 template parameters. */
14005 }
14006 }
14010 /* OK, now substitute the type of the non-type parameter. We
14011 couldn't do it earlier because it might be an auto parameter,
14012 and we wouldn't need to if we had an argument. */
14021 }
14024 }
14027 {
14035 {
14039 }
14042 {
14046 }
14049 {
14053 }
14059 }
14062 /* We should never be tsubsting a binfo. */
14066 /* A vector of template arguments. */
14072 {
14076 /* [temp.deduct]
14078 Type deduction may fail for any of the following
14079 reasons:
14081 -- Attempting to create a pointer to reference type.
14082 -- Attempting to create a reference to a reference type or
14083 a reference to void.
14085 Core issue 106 says that creating a reference to a reference
14086 during instantiation is no longer a cause for failure. We
14087 only enforce this check in strict C++98 mode. */
14091 {
14094 /* We keep track of the last time we issued this error
14095 message to avoid spewing a ton of messages during a
14096 single bad template instantiation. */
14099 {
14104 else
14107 }
14110 }
14114 {
14116 {
14119 type);
14120 else
14122 type);
14123 }
14125 }
14127 {
14131 }
14133 /* In C++0x, during template argument substitution, when there is an
14134 attempt to create a reference to a reference type, reference
14135 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14137 "If a template-argument for a template-parameter T names a type
14138 that is a reference to a type A, an attempt to create the type
14139 'lvalue reference to cv T' creates the type 'lvalue reference to
14140 A,' while an attempt to create the type type rvalue reference to
14141 cv T' creates the type T"
14142 */
14143 r = cp_build_reference_type
14146 else
14151 /* Will this ever be needed for TYPE_..._TO values? */
14155 }
14157 {
14160 {
14161 /* [temp.deduct]
14163 Type deduction may fail for any of the following
14164 reasons:
14166 -- Attempting to create "pointer to member of T" when T
14167 is not a class type. */
14171 }
14173 {
14177 }
14179 {
14183 }
14186 {
14187 /* The type of the implicit object parameter gets its
14188 cv-qualifiers from the FUNCTION_TYPE. */
14189 tree memptr;
14190 tree method_type
14195 complain);
14196 }
14197 else
14200 complain);
14201 }
14204 {
14205 tree fntype;
14206 tree specs;
14211 /* Substitute the exception specification. */
14219 }
14221 {
14226 /* As an optimization, we avoid regenerating the array type if
14227 it will obviously be the same as T. */
14231 /* These checks should match the ones in create_array_type_for_decl.
14233 [temp.deduct]
14235 The deduction may fail for any of the following reasons:
14237 -- Attempting to create an array with an element type that
14238 is void, a function type, or a reference type, or [DR337]
14239 an abstract class type. */
14245 {
14249 }
14257 {
14260 }
14263 }
14266 {
14278 {
14282 }
14284 {
14285 /* Normally, make_typename_type does not require that the CTX
14286 have complete type in order to allow things like:
14288 template <class T> struct S { typename S<T>::X Y; };
14290 But, such constructs have already been resolved by this
14291 point, so here CTX really should have complete type, unless
14292 it's a partial instantiation. */
14295 {
14299 }
14300 }
14307 {
14310 }
14313 {
14315 {
14319 else
14321 }
14323 {
14327 else
14329 }
14330 }
14332 return cp_build_qualified_type_real
14334 }
14337 {
14349 }
14352 {
14353 tree type;
14369 complain);
14370 }
14373 {
14374 tree type;
14385 {
14387 {
14391 }
14394 }
14405 else
14406 {
14410 /* In a template ~id could be either a complement expression
14411 or an unqualified-id naming a destructor; if instantiating
14412 it produces an expression, it's not an id-expression or
14413 member access. */
14416 }
14421 }
14424 {
14428 }
14432 {
14433 tree r;
14437 else
14445 }
14460 /* We should use one of the expression tsubsts for these codes. */
14466 }
14467 }
14469 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14470 expression on the left-hand side of the "." or "->" operator. We
14471 only do the lookup if we had a dependent BASELINK. Otherwise we
14472 adjust it onto the instantiated heirarchy. */
14474 static tree
14477 {
14489 {
14496 }
14503 {
14509 /* Treat as-if non-dependent below. */
14514 {
14520 }
14524 }
14525 else
14526 /* We're going to overwrite pieces below, make a duplicate. */
14529 /* If lookup found a single function, mark it as used at this point.
14530 (If lookup found multiple functions the one selected later by
14531 overload resolution will be marked as used at that point.) */
14537 {
14538 /* Add back the template arguments, if present. */
14543 /* Update the conversion operator type. */
14545 }
14551 {
14553 qualifying_scope,
14554 object_type);
14556 /* We need to call adjust_result_of_qualified_name_lookup in case the
14557 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14558 so that we still get virtual function binding. */
14560 }
14563 }
14565 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14566 true if the qualified-id will be a postfix-expression in-and-of
14567 itself; false if more of the postfix-expression follows the
14568 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14569 of "&". */
14571 static tree
14575 {
14576 tree expr;
14577 tree scope;
14578 tree name;
14580 tree template_args;
14585 /* Figure out what name to look up. */
14588 {
14598 }
14599 else
14600 {
14603 }
14605 /* Substitute into the qualifying scope. When there are no ARGS, we
14606 are just trying to simplify a non-dependent expression. In that
14607 case the qualifying scope may be dependent, and, in any case,
14608 substituting will not help. */
14611 {
14614 }
14615 else
14619 {
14626 }
14629 {
14631 {
14632 /* A BIT_NOT_EXPR is used to represent a destructor. */
14634 {
14638 }
14639 else
14642 }
14643 else
14647 {
14649 {
14653 }
14655 }
14656 }
14659 {
14661 scope);
14662 /* Remember that there was a reference to this entity. */
14665 }
14668 {
14674 }
14677 {
14680 complain);
14681 else
14683 }
14689 {
14690 expr = (adjust_result_of_qualified_name_lookup
14692 expr = (finish_qualified_id_expr
14696 }
14698 /* Expressions do not generally have reference type. */
14700 /* However, if we're about to form a pointer-to-member, we just
14701 want the referenced member referenced. */
14709 }
14711 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14712 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14713 for tsubst. */
14715 static tree
14718 {
14725 {
14726 /* If we had an initializer but it
14727 instantiated to nothing,
14728 value-initialize the object. This will
14729 only occur when the initializer was a
14730 pack expansion where the parameter packs
14731 used in that expansion were of length
14732 zero. */
14734 complain);
14739 }
14742 }
14744 /* Like tsubst, but deals with expressions. This function just replaces
14745 template parms; to finish processing the resultant expression, use
14746 tsubst_copy_and_build or tsubst_expr. */
14748 static tree
14750 {
14752 tree r;
14760 {
14765 {
14766 /* We get here for a use of 'this' in an NSDMI. */
14770 /* This can happen for a parameter name used later in a function
14771 declaration (such as in a late-specified return type). Just
14772 make a dummy decl, since it's only used for its type. */
14775 /* Give it the template pattern as its context; its true context
14776 hasn't been instantiated yet and this is good enough for
14777 mangling. */
14779 }
14788 {
14789 tree enum_type;
14790 tree v;
14794 /* There is no need to substitute into namespace-scope
14795 enumerators. */
14798 /* If ARGS is NULL, then T is known to be non-dependent. */
14802 /* Unfortunately, we cannot just call lookup_name here.
14803 Consider:
14805 template <int I> int f() {
14806 enum E { a = I };
14807 struct S { void g() { E e = a; } };
14808 };
14810 When we instantiate f<7>::S::g(), say, lookup_name is not
14811 clever enough to find f<7>::a. */
14812 enum_type
14822 /* We didn't find the name. That should never happen; if
14823 name-lookup found it during preliminary parsing, we
14824 should find it again here during instantiation. */
14826 }
14831 {
14832 /* Check for a local specialization set up by
14833 tsubst_pack_expansion. */
14835 {
14839 }
14841 /* When retrieving a capture pack from a generic lambda, remove the
14842 lambda call op's own template argument list from ARGS. Only the
14843 template arguments active for the closure type should be used to
14844 retrieve the pack specialization. */
14850 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14851 tsubst_decl put in the hash table. */
14853 }
14856 {
14857 tree ctx;
14862 {
14865 {
14869 }
14871 }
14872 }
14882 {
14885 {
14886 /* First try name lookup to find the instantiation. */
14889 {
14890 /* Make sure that the one we found is the one we want. */
14894 }
14898 else
14899 {
14900 /* This can happen for a variable used in a
14901 late-specified return type of a local lambda, or for a
14902 local static or constant. Building a new VAR_DECL
14903 should be OK in all those cases. */
14906 /* Avoid infinite recursion (79640). */
14909 {
14910 /* We can't call cp_finish_decl, so handle the
14911 initializer by hand. */
14926 }
14933 }
14934 /* Remember this for subsequent uses. */
14937 }
14938 }
14939 else
14949 /* An OVERLOAD will always be a non-dependent overload set; an
14950 overload set from function scope will just be represented with an
14951 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14953 /* We must have marked any lookups as persistent. */
14969 {
14970 /* Template template argument like the following example need
14971 special treatment:
14973 template <template <class> class TT> struct C {};
14974 template <class T> struct D {
14975 template <class U> struct E {};
14976 C<E> c; // #1
14977 };
14978 D<int> d; // #2
14980 We are processing the template argument `E' in #1 for
14981 the template instantiation #2. Originally, `E' is a
14982 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14983 have to substitute this with one having context `D<int>'. */
14987 {
14988 /* When rewriting a constructor into a deduction guide, a
14989 non-dependent name can become dependent, so memtmpl<args>
14990 becomes context::template memtmpl<args>. */
14994 }
14996 }
14997 else
14998 /* Ordinary template template argument. */
15003 {
15004 /* Handle location wrappers by substituting the wrapped node
15005 first, *then* reusing the resulting type. Doing the type
15006 first ensures that we handle template parameters and
15007 parameter pack expansions. */
15011 }
15021 {
15025 }
15030 {
15039 /* We only want to compute the number of arguments. */
15042 else
15049 {
15051 /* Set TREE_USED for the benefit of -Wunused. */
15055 }
15063 {
15068 else
15074 else
15077 }
15078 else
15080 }
15082 {
15090 }
15091 /* Fall through */
15107 {
15111 }
15114 {
15115 tree object;
15116 tree name;
15121 {
15125 }
15128 {
15138 }
15143 in_decl);
15144 else
15147 }
15185 {
15189 }
15192 {
15197 }
15200 {
15204 }
15207 {
15215 }
15221 {
15228 }
15231 {
15238 }
15241 {
15248 }
15251 {
15252 /* Substituted template arguments */
15261 }
15264 {
15284 }
15309 /* Fall through. */
15312 {
15315 }
15316 else
15320 /* This is handled by tsubst_copy_and_build. */
15324 {
15328 }
15331 /* We shouldn't have built any of these during initial template
15332 generation. Instead, they should be built during instantiation
15333 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15337 {
15347 }
15365 {
15366 /* Instantiate any typedefs in the type. */
15371 }
15374 /* These can sometimes show up in a partial instantiation, but never
15375 involve template parms. */
15391 /* ??? There's no point in copying it for now, but maybe some
15392 day it will contain more information, such as a pointer back
15393 to the containing function, inlined copy or so. */
15397 /* We shouldn't get here, but keep going if !flag_checking. */
15401 }
15402 }
15404 /* Helper function for tsubst_omp_clauses, used for instantiation of
15405 OMP_CLAUSE_DECL of clauses. */
15407 static tree
15409 tree in_decl)
15410 {
15414 /* Handle an OpenMP array section represented as a TREE_LIST (or
15415 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15416 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15417 TREE_LIST. We can handle it exactly the same as an array section
15418 (purpose, value, and a chain), even though the nomenclature
15419 (low_bound, length, etc) is different. */
15421 {
15422 tree low_bound
15428 in_decl);
15437 }
15440 /* Undo convert_from_reference tsubst_expr could have called. */
15446 }
15448 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15450 static tree
15453 {
15458 {
15464 {
15467 {
15473 }
15474 /* FALLTHRU */
15489 in_decl);
15521 {
15524 {
15531 }
15532 else
15534 }
15537 in_decl);
15543 in_decl);
15551 in_decl);
15553 {
15556 }
15561 else
15564 in_decl,
15588 }
15591 {
15601 /* tsubst_expr on SCOPE_REF results in returning
15602 finish_non_static_data_member result. Undo that here. */
15606 {
15611 {
15615 CASE_CONVERT:
15624 /* FALLTHRU */
15628 }
15629 }
15635 {
15638 {
15641 }
15642 }
15646 }
15647 }
15651 {
15656 {
15659 }
15660 }
15662 }
15664 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15666 static tree
15668 tree in_decl)
15669 {
15670 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15690 {
15693 else
15694 {
15698 }
15699 }
15704 #undef RECUR
15705 }
15707 /* Used to temporarily communicate the list of #pragma omp parallel
15708 clauses to #pragma omp for instantiation if they are combined
15709 together. */
15713 /* Substitute one OMP_FOR iterator. */
15715 static void
15720 {
15721 #define RECUR(NODE) \
15722 tsubst_expr ((NODE), args, complain, in_decl, \
15723 integral_constant_expression_p)
15730 {
15733 }
15739 {
15740 /* We need to jump through some hoops to handle declarations in the
15741 init-statement, since we might need to handle auto deduction,
15742 but we need to keep control of initialization. */
15746 }
15747 else
15748 {
15750 {
15753 {
15757 {
15761 CASE_CONVERT:
15769 {
15772 }
15773 /* FALLTHRU */
15777 }
15778 }
15779 }
15780 else
15782 }
15793 {
15795 {
15796 /* Declare the variable, but don't let that initialize it. */
15801 }
15806 {
15811 }
15812 else
15819 }
15822 {
15823 /* Declare and initialize the variable. */
15826 }
15828 {
15832 {
15834 {
15840 {
15843 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15848 }
15851 {
15853 decl);
15855 }
15858 {
15860 decl);
15862 }
15863 else
15865 }
15868 }
15870 {
15875 {
15878 }
15879 }
15880 }
15883 {
15887 }
15888 else
15892 {
15903 {
15911 }
15912 else
15918 {
15924 }
15928 {
15936 }
15937 else
15943 }
15949 #undef RECUR
15950 }
15952 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15953 of OMP_TARGET's body. */
15955 static tree
15957 {
15960 {
15969 }
15971 }
15973 /* Helper function for tsubst_expr. For decomposition declaration
15974 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15975 also the corresponding decls representing the identifiers
15976 of the decomposition declaration. Return DECL if successful
15977 or error_mark_node otherwise, set *FIRST to the first decl
15978 in the list chained through DECL_CHAIN and *CNT to the number
15979 of such decls. */
15981 static tree
15985 {
15990 decl2
15995 {
15997 {
16000 }
16017 {
16020 }
16021 else
16023 }
16026 }
16028 /* Like tsubst_copy for expressions, etc. but also does semantic
16029 processing. */
16031 tree
16034 {
16035 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16036 #define RECUR(NODE) \
16037 tsubst_expr ((NODE), args, complain, in_decl, \
16038 integral_constant_expression_p)
16041 tree r;
16042 location_t loc;
16054 {
16056 {
16057 tree_stmt_iterator i;
16061 }
16076 else
16086 {
16088 tree init;
16094 {
16104 else
16106 }
16108 {
16109 /* Don't build up decls for a variadic capture proxy, we'll
16110 instantiate the elements directly as needed. */
16112 }
16115 {
16116 /* We're in tsubst_lambda_expr, we've already inserted a new
16117 capture proxy, so look it up and register it. */
16123 }
16126 /* Don't copy the old closure; we'll create a new one in
16127 tsubst_lambda_expr. */
16129 else
16130 {
16134 {
16135 /* By marking the declaration as instantiated, we avoid
16136 trying to instantiate it. Since instantiate_decl can't
16137 handle local variables, and since we've already done
16138 all that needs to be done, that's the right thing to
16139 do. */
16144 /* Anonymous aggregates are a special case. */
16147 {
16150 {
16154 }
16156 }
16162 {
16167 }
16168 else
16169 {
16174 {
16175 /* For __PRETTY_FUNCTION__ we have to adjust the
16176 initializer. */
16180 }
16181 else
16185 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16190 {
16192 tree first;
16193 tree ndecl
16201 }
16202 else
16204 }
16205 }
16206 }
16209 }
16219 {
16223 }
16228 {
16229 /* Construct another range_for, if this is not a final
16230 substitution (for inside inside a generic lambda of a
16231 template). Otherwise convert to a regular for. */
16233 stmt = (processing_template_decl
16249 {
16253 }
16254 else
16255 {
16261 }
16267 }
16274 {
16278 }
16284 {
16288 }
16301 else
16302 {
16309 }
16315 {
16324 }
16332 else
16340 else
16361 {
16368 }
16372 {
16374 tree label;
16381 }
16387 /* Computed goto's must be tsubst'd into. On the other hand,
16388 non-computed gotos must not be; the identifier in question
16389 will have no binding. */
16391 else
16397 {
16413 }
16418 {
16423 }
16424 else
16425 {
16430 else
16437 else
16443 else
16445 }
16449 {
16453 {
16455 /* Prevent instantiate_decl from trying to instantiate
16456 this variable. We've already done all that needs to be
16457 done. */
16460 }
16465 }
16471 {
16472 /* Local classes are not independent templates; they are
16473 instantiated along with their containing function. And this
16474 way we don't have to deal with pushing out of one local class
16475 to instantiate a member of another local class. */
16476 /* Closures are handled by the LAMBDA_EXPR. */
16486 }
16490 {
16491 tree condition;
16494 condition =
16496 args,
16505 }
16511 in_decl);
16546 {
16559 in_decl);
16561 {
16568 }
16580 integral_constant_expression_p);
16591 else
16592 {
16600 }
16604 }
16609 /* FALLTHRU */
16616 in_decl);
16633 in_decl);
16644 {
16647 {
16648 /* For combined target teams, ensure the num_teams and
16649 thread_limit clause expressions are evaluated on the host,
16650 before entering the target construct. */
16651 tree c;
16657 {
16666 OMP_CLAUSE_FIRSTPRIVATE);
16670 }
16671 }
16672 }
16732 {
16737 {
16740 }
16746 }
16747 else
16748 {
16755 {
16758 }
16761 {
16766 {
16769 }
16775 }
16776 else
16777 {
16781 }
16784 }
16788 {
16794 {
16798 {
16803 }
16807 }
16808 else
16809 {
16814 }
16815 }
16819 {
16823 }
16836 /* If the first operand was a statement, we're done with it. */
16840 complain));
16854 integral_constant_expression_p));
16855 }
16858 out:
16861 #undef RECUR
16862 #undef RETURN
16863 }
16865 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16866 function. For description of the body see comment above
16867 cp_parser_omp_declare_reduction_exprs. */
16869 static void
16871 {
16877 tree_stmt_iterator tsi;
16888 {
16907 }
16909 {
16929 }
16930 }
16932 /* T is a postfix-expression that is not being used in a function
16933 call. Return the substituted version of T. */
16935 static tree
16937 tsubst_flags_t complain,
16938 tree in_decl)
16939 {
16943 else
16949 }
16951 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
16952 instantiation context. Instantiating a pack expansion containing a lambda
16953 might result in multiple lambdas all based on the same lambda in the
16954 template. */
16956 tree
16958 {
16972 else
16980 {
16992 else
16997 {
17006 }
17007 else
17008 {
17014 }
17015 }
17019 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17037 else
17038 {
17039 /* Fix the type of 'this'. */
17045 {
17049 }
17050 else
17051 {
17055 }
17057 /* Let finish_function set this. */
17078 /* The capture list was built up in reverse order; fix that now. */
17085 }
17092 }
17094 /* Like tsubst but deals with expressions and performs semantic
17095 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17097 tree
17099 tree args,
17100 tsubst_flags_t complain,
17101 tree in_decl,
17104 {
17105 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17106 #define RECUR(NODE) \
17107 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17109 integral_constant_expression_p)
17112 location_t loc;
17121 /* N3276 decltype magic only applies to calls at the top level or on the
17122 right side of a comma. */
17127 {
17130 /* Fall through. */
17132 {
17133 tree decl;
17134 cp_id_kind idk;
17139 {
17142 }
17144 /* Look up the name. */
17147 /* By convention, expressions use ERROR_MARK_NODE to indicate
17148 failure, not NULL_TREE. */
17154 integral_constant_expression_p,
17162 input_location);
17166 {
17170 }
17172 }
17175 {
17176 tree object;
17186 {
17191 }
17197 {
17200 }
17201 else
17208 else
17210 }
17213 {
17217 {
17218 /* A type conversion to reference type will be enclosed in
17219 such an indirect ref, but the substitution of the cast
17220 will have also added such an indirect ref. */
17222 }
17223 else
17231 }
17234 {
17238 }
17241 {
17245 {
17250 }
17252 /* We'll pass this to convert_nontype_argument again, we don't need
17253 to actually perform any conversion here. */
17259 flags));
17260 }
17263 {
17267 }
17274 {
17275 tree type;
17281 {
17286 }
17293 {
17311 }
17314 }
17348 else
17350 in_decl);
17385 {
17392 tree r = build_x_binary_op
17394 op0,
17396 ? ERROR_MARK
17398 op1,
17400 ? ERROR_MARK
17408 }
17411 {
17415 }
17431 /* Fall through */
17434 {
17435 tree r;
17441 {
17442 /* When there are no ARGS, we are trying to evaluate a
17443 non-dependent expression from the parser. Trying to do
17444 the substitutions may not work. */
17447 }
17448 else
17449 {
17454 else
17457 /*integral_constant_expression_p=*/
17461 }
17465 else
17469 {
17471 {
17473 {
17477 }
17478 else
17482 }
17484 }
17486 }
17489 {
17499 }
17515 {
17519 tree r = build_x_modify_expr
17522 /* TREE_NO_WARNING must be set if either the expression was
17523 parenthesized or it uses an operator such as >>= rather
17524 than plain assignment. In the former case, it was already
17525 set and must be copied. In the latter case,
17526 build_x_modify_expr sets it and it must not be reset
17527 here. */
17532 }
17537 /* Remember that there was a reference to this entity. */
17544 {
17549 tree ret;
17553 else
17554 {
17558 }
17560 /* If there was an initializer in the original tree, but it
17561 instantiated to an empty list, then we should pass a
17562 non-NULL empty vector to tell build_new that it was an
17563 empty initializer() rather than no initializer. This can
17564 only happen when the initializer is a pack expansion whose
17565 parameter packs are of length zero. */
17568 else
17569 {
17573 else
17574 {
17577 }
17578 }
17584 complain);
17592 }
17595 {
17601 complain));
17602 }
17605 {
17609 integral_constant_expression_p);
17611 op0,
17614 }
17617 {
17618 tree function;
17623 tree ret;
17626 /* Internal function with no arguments. */
17630 /* When we parsed the expression, we determined whether or
17631 not Koenig lookup should be performed. */
17634 {
17637 }
17639 {
17644 }
17646 {
17647 /* Do nothing; calling tsubst_copy_and_build on an identifier
17648 would incorrectly perform unqualified lookup again.
17650 Note that we can also have an IDENTIFIER_NODE if the earlier
17651 unqualified lookup found a member function; in that case
17652 koenig_p will be false and we do want to do the lookup
17653 again to find the instantiated member function.
17655 FIXME but doing that causes c++/15272, so we need to stop
17656 using IDENTIFIER_NODE in that situation. */
17658 }
17659 else
17660 {
17662 {
17668 }
17669 else
17674 /* Avoid error about taking the address of a constructor. */
17678 in_decl,
17680 integral_constant_expression_p);
17684 }
17689 {
17694 else
17695 {
17696 /* Expand the pack expansion and push each entry onto
17697 CALL_ARGS. */
17700 {
17705 {
17710 }
17711 }
17712 else
17713 {
17714 /* A partial substitution. Add one entry. */
17716 }
17717 }
17718 }
17720 /* We do not perform argument-dependent lookup if normal
17721 lookup finds a non-function, in accordance with the
17722 expected resolution of DR 218. */
17725 /* If lookup found a member function, the Koenig lookup is
17726 not appropriate, even if an unqualified-name was used
17727 to denote the function. */
17730 /* Only do this when substitution turns a dependent call
17731 into a non-dependent call. */
17739 {
17741 {
17742 /* For backwards compatibility and good diagnostics, try
17743 the unqualified lookup again if we aren't in SFINAE
17744 context. */
17745 tree unq = (tsubst_copy_and_build
17747 integral_constant_expression_p));
17749 {
17752 }
17755 {
17756 /* In a lambda fn, we have to be careful to not
17757 introduce new this captures. Legacy code can't
17758 be using lambdas anyway, so it's ok to be
17759 stricter. */
17764 "and no declarations were found by "
17765 "argument-dependent lookup at the point "
17772 else
17776 {
17787 {
17789 input_location);
17791 "declarations in dependent base %qT are "
17797 else
17801 }
17802 else
17804 "%qD declared here, later in the "
17807 {
17810 }
17811 }
17814 }
17815 }
17817 {
17822 }
17823 }
17825 /* Remember that there was a reference to this entity. */
17829 {
17832 }
17834 /* Put back tf_decltype for the actual call. */
17839 {
17843 {
17845 "wrong number of arguments to "
17848 }
17849 else
17851 input_location),
17856 /* Unsupported internal function with arguments. */
17858 }
17861 complain);
17863 {
17878 complain);
17879 else
17880 ret = (build_new_method_call
17885 complain));
17886 }
17887 else
17890 koenig_p,
17891 complain);
17896 {
17902 {
17908 {
17911 else
17913 /* The thunk location is not interesting. */
17915 }
17916 }
17917 }
17920 }
17923 {
17929 {
17931 {
17936 }
17937 else
17938 {
17943 }
17945 }
17946 else
17947 {
17950 }
17955 }
17958 {
17963 input_location));
17964 }
17967 {
17975 {
17976 /* We have pack expansions, so expand those and
17977 create a new list out of it. */
17980 tree chain;
17983 /* Expand the argument expressions. */
17991 /* Build the rest of the list. */
17996 /* Determine the number of arguments. */
17998 {
18001 }
18004 else
18005 {
18006 /* Since we only performed a partial substitution into
18007 the argument pack, we only RETURN (a single list
18008 node. */
18015 }
18017 /* Convert the argument vectors into a TREE_LIST */
18020 {
18021 /* Grab the Ith values. */
18022 i--;
18025 value
18029 /* Build the list (backwards). */
18031 }
18034 }
18050 }
18053 {
18054 tree object;
18055 tree object_type;
18056 tree member;
18057 tree r;
18061 /* Remember that there was a reference to this entity. */
18072 else
18078 {
18083 }
18087 {
18089 {
18094 {
18097 }
18099 {
18104 }
18105 }
18106 }
18109 {
18110 /* Lookup the template functions now that we know what the
18111 scope is. */
18119 {
18122 args);
18123 member = (adjust_result_of_qualified_name_lookup
18125 object_type));
18126 }
18127 else
18128 {
18130 input_location);
18132 }
18133 }
18137 {
18139 {
18143 else
18146 }
18148 }
18152 complain);
18156 }
18163 {
18171 tree r;
18176 /* We do not want to process the index of aggregate
18177 initializers as they are identifier nodes which will be
18178 looked up by digest_init. */
18184 {
18186 /* An identifier index is looked up in the type
18187 being initialized, not the current scope. */
18192 {
18193 /* Substitute into the pack expansion. */
18195 in_decl);
18199 ;
18201 /* Just move the argument into place. */
18203 else
18204 {
18205 /* Update the length of the final CONSTRUCTOR
18206 arguments vector, and note that we will need to
18207 copy.*/
18210 }
18211 }
18212 else
18214 }
18217 {
18222 {
18224 {
18229 }
18230 else
18232 }
18233 }
18239 {
18244 }
18248 }
18251 {
18254 {
18257 }
18258 else
18259 {
18262 }
18263 }
18269 {
18270 /* We don't build decls for an instantiation of a
18271 variadic capture proxy, we instantiate the elements
18272 when needed. */
18275 }
18276 /* Fall through */
18279 {
18281 /* ??? We're doing a subset of finish_id_expression here. */
18283 && !processing_template_decl
18284 && !cp_unevaluated_operand
18287 {
18289 /* Replace an evaluated use of the thread_local variable with
18290 a call to its wrapper. */
18292 }
18297 /* If the original type was a reference, we'll be wrapped in
18298 the appropriate INDIRECT_REF. */
18301 }
18304 {
18308 }
18311 {
18312 tree object_ptr
18319 }
18326 {
18337 }
18340 {
18346 integral_constant_expression_p);
18350 /* If the resulting list of expression statement is empty,
18351 fold it further into void_node. */
18356 }
18359 {
18363 }
18366 /* We can get here for a constant initializer of non-dependent type.
18367 FIXME stop folding in cp_parser_initializer_clause. */
18368 {
18370 complain);
18372 }
18376 integral_constant_expression_p));
18382 {
18387 complain));
18388 }
18395 /* We should only see these for location wrapper nodes, or within
18396 instantiate_non_dependent_expr (when args is NULL_TREE). */
18401 /* fallthrough. */
18404 /* Handle Objective-C++ constructs, if appropriate. */
18405 {
18406 tree subst
18411 }
18413 }
18415 #undef RECUR
18416 #undef RETURN
18417 out:
18420 }
18422 /* Verify that the instantiated ARGS are valid. For type arguments,
18423 make sure that the type's linkage is ok. For non-type arguments,
18424 make sure they are constants if they are integral or enumerations.
18425 Emit an error under control of COMPLAIN, and return TRUE on error. */
18427 static bool
18429 {
18433 {
18443 }
18445 {
18446 /* [basic.link]: A name with no linkage (notably, the name
18447 of a class or enumeration declared in a local scope)
18448 shall not be used to declare an entity with linkage.
18449 This implies that names with no linkage cannot be used as
18450 template arguments
18452 DR 757 relaxes this restriction for C++0x. */
18457 {
18458 /* DR 488 makes use of a type with no linkage cause
18459 type deduction to fail. */
18461 {
18464 else
18467 }
18469 }
18470 /* In order to avoid all sorts of complications, we do not
18471 allow variably-modified types as template arguments. */
18473 {
18477 }
18478 }
18479 /* Class template and alias template arguments should be OK. */
18481 ;
18482 /* A non-type argument of integral or enumerated type must be a
18483 constant. */
18488 {
18492 }
18494 }
18496 static bool
18498 {
18503 {
18506 }
18510 }
18512 /* We're out of SFINAE context now, so generate diagnostics for the access
18513 errors we saw earlier when instantiating D from TMPL and ARGS. */
18515 static void
18517 {
18529 }
18531 /* Instantiate the indicated variable, function, or alias template TMPL with
18532 the template arguments in TARG_PTR. */
18534 static tree
18536 {
18538 tree fndecl;
18539 tree gen_tmpl;
18540 tree spec;
18548 /* If this function is a clone, handle it specially. */
18550 {
18551 tree spec;
18552 tree clone;
18554 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18555 DECL_CLONED_FUNCTION. */
18561 /* Look for the clone. */
18565 /* We should always have found the clone by now. */
18568 }
18573 /* Check to see if we already have this specialization. */
18577 /* targ_ptr only has the innermost template args, so add the outer ones
18578 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18579 the case of a non-dependent call within a template definition). */
18580 targ_ptr = (add_outermost_template_args
18582 targ_ptr));
18584 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18585 but it doesn't seem to be on the hot path. */
18594 {
18596 {
18600 }
18602 }
18605 complain))
18608 /* We are building a FUNCTION_DECL, during which the access of its
18609 parameters and return types have to be checked. However this
18610 FUNCTION_DECL which is the desired context for access checking
18611 is not built yet. We solve this chicken-and-egg problem by
18612 deferring all checks until we have the FUNCTION_DECL. */
18615 /* Instantiation of the function happens in the context of the function
18616 template, not the context of the overload resolution we're doing. */
18618 /* If there are dependent arguments, e.g. because we're doing partial
18619 ordering, make sure processing_template_decl stays set. */
18623 {
18627 }
18633 {
18634 /* We need to determine if we're using a partial or explicit
18635 specialization now, because the type of the variable could be
18636 different. */
18642 {
18647 }
18648 }
18650 /* Substitute template parameters to obtain the specialization. */
18658 {
18661 }
18663 /* The DECL_TI_TEMPLATE should always be the immediate parent
18664 template, not the most general template. */
18668 /* Now we know the specialization, compute access previously
18669 deferred. Do no access control for inheriting constructors,
18670 as we already checked access for the inherited constructor. */
18673 {
18678 }
18681 /* If we've just instantiated the main entry point for a function,
18682 instantiate all the alternate entry points as well. We do this
18683 by cloning the instantiation of the main entry point, not by
18684 instantiating the template clones. */
18689 {
18691 {
18692 /* Remember to reinstantiate when we're out of SFINAE so the user
18693 can see the errors. */
18695 }
18697 }
18699 }
18701 /* Wrapper for instantiate_template_1. */
18703 tree
18705 {
18706 tree ret;
18711 }
18713 /* Instantiate the alias template TMPL with ARGS. Also push a template
18714 instantiation level, which instantiate_template doesn't do because
18715 functions and variables have sufficient context established by the
18716 callers. */
18718 static tree
18720 {
18727 {
18730 }
18732 args =
18740 /* We can't free this if a pending_template entry or last_error_tinst_level
18741 is pointing at it. */
18747 }
18749 /* PARM is a template parameter pack for FN. Returns true iff
18750 PARM is used in a deducible way in the argument list of FN. */
18752 static bool
18754 {
18757 {
18759 tree packs;
18765 {
18766 /* The template parameter pack is used in a function parameter
18767 pack. If this is the end of the parameter list, the
18768 template parameter pack is deducible. */
18771 else
18772 /* Otherwise, not. Well, it could be deduced from
18773 a non-pack parameter, but doing so would end up with
18774 a deduction mismatch, so don't bother. */
18776 }
18777 }
18778 /* The template parameter pack isn't used in any function parameter
18779 packs, but it might be used deeper, e.g. tuple<Args...>. */
18781 }
18783 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18784 NARGS elements of the arguments that are being used when calling
18785 it. TARGS is a vector into which the deduced template arguments
18786 are placed.
18788 Returns either a FUNCTION_DECL for the matching specialization of FN or
18789 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18790 true, diagnostics will be printed to explain why it failed.
18792 If FN is a conversion operator, or we are trying to produce a specific
18793 specialization, RETURN_TYPE is the return type desired.
18795 The EXPLICIT_TARGS are explicit template arguments provided via a
18796 template-id.
18798 The parameter STRICT is one of:
18800 DEDUCE_CALL:
18801 We are deducing arguments for a function call, as in
18802 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18803 deducing arguments for a call to the result of a conversion
18804 function template, as in [over.call.object].
18806 DEDUCE_CONV:
18807 We are deducing arguments for a conversion function, as in
18808 [temp.deduct.conv].
18810 DEDUCE_EXACT:
18811 We are deducing arguments when doing an explicit instantiation
18812 as in [temp.explicit], when determining an explicit specialization
18813 as in [temp.expl.spec], or when taking the address of a function
18814 template, as in [temp.deduct.funcaddr]. */
18816 tree
18818 tree explicit_targs,
18819 tree targs,
18822 tree return_type,
18823 unification_kind_t strict,
18827 {
18828 tree parms;
18829 tree fntype;
18842 tree tinst;
18848 full_targs = (add_outermost_template_args
18850 targs));
18855 /* In C++0x, it's possible to have a function template whose type depends
18856 on itself recursively. This is most obvious with decltype, but can also
18857 occur with enumeration scope (c++/48969). So we need to catch infinite
18858 recursion and reject the substitution at deduction time; this function
18859 will return error_mark_node for any repeated substitution.
18861 This also catches excessive recursion such as when f<N> depends on
18862 f<N-1> across all integers, and returns error_mark_node for all the
18863 substitutions back up to the initial one.
18865 This is, of course, not reentrant. */
18875 {
18876 /* [temp.deduct]
18878 The specified template arguments must match the template
18879 parameters in kind (i.e., type, nontype, template), and there
18880 must not be more arguments than there are parameters;
18881 otherwise type deduction fails.
18883 Nontype arguments must match the types of the corresponding
18884 nontype template parameters, or must be convertible to the
18885 types of the corresponding nontype parameters as specified in
18886 _temp.arg.nontype_, otherwise type deduction fails.
18888 All references in the function type of the function template
18889 to the corresponding template parameters are replaced by the
18890 specified template argument values. If a substitution in a
18891 template parameter or in the function type of the function
18892 template results in an invalid type, type deduction fails. */
18903 explicit_targs);
18905 /* Adjust any explicit template arguments before entering the
18906 substitution context. */
18907 explicit_targs
18909 complain,
18915 /* Substitute the explicit args into the function type. This is
18916 necessary so that, for instance, explicitly declared function
18917 arguments can match null pointed constants. If we were given
18918 an incomplete set of explicit args, we must not do semantic
18919 processing during substitution as we could create partial
18920 instantiations. */
18922 {
18927 /* Dig out the actual parm. */
18930 {
18933 }
18935 {
18938 }
18941 /* No explicit argument for this template parameter. */
18945 {
18946 /* Mark the argument pack as "incomplete". We could
18947 still deduce more arguments during unification.
18948 We remove this mark in type_unification_real. */
18950 {
18954 }
18956 /* We have some incomplete argument packs. */
18958 }
18959 }
18963 {
18966 }
18969 /* Ignore any access checks; we'll see them again in
18970 instantiate_template and they might have the wrong
18971 access path at this point. */
18983 /* Place the explicitly specified arguments in TARGS. */
18987 }
18989 /* Never do unification on the 'this' parameter. */
18993 {
18994 /* We're deducing for a call to the result of a template conversion
18995 function. The parms we really want are in return_type. */
18999 }
19001 {
19010 }
19012 /* We allow incomplete unification without an error message here
19013 because the standard doesn't seem to explicitly prohibit it. Our
19014 callers must be ready to deal with unification failures in any
19015 event. */
19018 /* If we aren't explaining yet, push tinst context so we can see where
19019 any errors (e.g. from class instantiations triggered by instantiation
19020 of default template arguments) come from. If we are explaining, this
19021 context is redundant. */
19023 {
19026 }
19028 /* type_unification_real will pass back any access checks from default
19029 template argument substitution. */
19041 /* Now that we have bindings for all of the template arguments,
19042 ensure that the arguments deduced for the template template
19043 parameters have compatible template parameter lists. We cannot
19044 check this property before we have deduced all template
19045 arguments, because the template parameter types of a template
19046 template parameter might depend on prior template parameters
19047 deduced after the template template parameter. The following
19048 ill-formed example illustrates this issue:
19050 template<typename T, template<T> class C> void f(C<5>, T);
19052 template<int N> struct X {};
19054 void g() {
19055 f(X<5>(), 5l); // error: template argument deduction fails
19056 }
19058 The template parameter list of 'C' depends on the template type
19059 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19060 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19061 time that we deduce 'C'. */
19064 {
19067 }
19069 /* All is well so far. Now, check:
19071 [temp.deduct]
19073 When all template arguments have been deduced, all uses of
19074 template parameters in nondeduced contexts are replaced with
19075 the corresponding deduced argument values. If the
19076 substitution results in an invalid type, as described above,
19077 type deduction fails. */
19080 {
19083 }
19085 /* Also collect access checks from the instantiation. */
19098 /* Now perform any access checks encountered during substitution. */
19105 /* If we're looking for an exact match, check that what we got
19106 is indeed an exact match. It might not be if some template
19107 parameters are used in non-deduced contexts. But don't check
19108 for an exact match if we have dependent template arguments;
19109 in that case we're doing partial ordering, and we already know
19110 that we have two candidates that will provide the actual type. */
19112 {
19116 tree sarg
19122 {
19126 }
19127 }
19129 /* After doing deduction with the inherited constructor, actually return an
19130 instantiation of the inheriting constructor. */
19136 fail:
19139 {
19141 /* Reset once we're all the way out. */
19143 }
19145 /* We can't free this if a pending_template entry or last_error_tinst_level
19146 is pointing at it. */
19152 }
19154 /* Adjust types before performing type deduction, as described in
19155 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19156 sections are symmetric. PARM is the type of a function parameter
19157 or the return type of the conversion function. ARG is the type of
19158 the argument passed to the call, or the type of the value
19159 initialized with the result of the conversion function.
19160 ARG_EXPR is the original argument expression, which may be null. */
19162 static int
19166 tree arg_expr)
19167 {
19171 {
19176 /* Swap PARM and ARG throughout the remainder of this
19177 function; the handling is precisely symmetric since PARM
19178 will initialize ARG rather than vice versa. */
19183 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19184 too, but here handle it by stripping the reference from PARM
19185 rather than by adding it to ARG. */
19193 /* Nothing else to do in this case. */
19198 }
19201 {
19202 /* [temp.deduct.call]
19204 If P is not a reference type:
19206 --If A is an array type, the pointer type produced by the
19207 array-to-pointer standard conversion (_conv.array_) is
19208 used in place of A for type deduction; otherwise,
19210 --If A is a function type, the pointer type produced by
19211 the function-to-pointer standard conversion
19212 (_conv.func_) is used in place of A for type deduction;
19213 otherwise,
19215 --If A is a cv-qualified type, the top level
19216 cv-qualifiers of A's type are ignored for type
19217 deduction. */
19222 else
19224 }
19226 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19227 reference to a cv-unqualified template parameter that does not represent a
19228 template parameter of a class template (during class template argument
19229 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19230 an lvalue, the type "lvalue reference to A" is used in place of A for type
19231 deduction. */
19238 /* try_one_overload doesn't provide an arg_expr, but
19239 functions are always lvalues. */
19243 /* [temp.deduct.call]
19245 If P is a cv-qualified type, the top level cv-qualifiers
19246 of P's type are ignored for type deduction. If P is a
19247 reference type, the type referred to by P is used for
19248 type deduction. */
19251 {
19254 }
19256 /* DR 322. For conversion deduction, remove a reference type on parm
19257 too (which has been swapped into ARG). */
19262 }
19264 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19265 template which does contain any deducible template parameters; check if
19266 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19267 unify_one_argument. */
19269 static int
19272 {
19273 tree type;
19277 else
19284 {
19288 }
19290 {
19295 }
19299 else
19301 }
19305 /* Returns true iff the expression EXPR is one from which a template
19306 argument can be deduced. In other words, if it's an undecorated
19307 use of a template non-type parameter. */
19309 static bool
19311 {
19312 /* Strip implicit conversions. */
19316 }
19318 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19319 deducible way; that is, if it has a max value of <PARM> - 1. */
19321 static bool
19323 {
19332 }
19334 /* Returns true iff the template arguments ARGS use a template parameter
19335 in a deducible way. */
19337 static bool
19339 {
19341 {
19346 else
19347 {
19354 else
19356 }
19359 }
19361 }
19363 /* Returns true iff TYPE contains any deducible references to template
19364 parameters, as per 14.8.2.5. */
19366 static bool
19368 {
19372 /* T
19373 cv-list T
19374 TT<T>
19375 TT<i>
19376 TT<> */
19381 /* T*
19382 T&
19383 T&& */
19387 /* T[integer-constant ]
19388 type [i] */
19393 /* T type ::*
19394 type T::*
19395 T T::*
19396 T (type ::*)()
19397 type (T::*)()
19398 type (type ::*)(T)
19399 type (T::*)(T)
19400 T (type ::*)(T)
19401 T (T::*)()
19402 T (T::*)(T) */
19405 || (uses_deducible_template_parms
19408 /* template-name <T> (where template-name refers to a class template)
19409 template-name <i> (where template-name refers to a class template) */
19416 /* type (T)
19417 T()
19418 T(T) */
19421 {
19430 }
19433 }
19435 /* Subroutine of type_unification_real and unify_pack_expansion to
19436 handle unification of a single P/A pair. Parameters are as
19437 for those functions. */
19439 static int
19443 {
19450 /* We can't deduce anything from this, but we might get all the
19451 template args from other function args. */
19454 /* Implicit conversions (Clause 4) will be performed on a function
19455 argument to convert it to the type of the corresponding function
19456 parameter if the parameter type contains no template-parameters that
19457 participate in template argument deduction. */
19460 /* For function parameters with no deducible template parameters,
19461 just return. We'll check non-dependent conversions later. */
19465 {
19467 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19468 | UNIFY_ALLOW_MORE_CV_QUAL
19482 }
19484 /* We only do these transformations if this is the top-level
19485 parameter_type_list in a call or declaration matching; in other
19486 situations (nested function declarators, template argument lists) we
19487 won't be comparing a type to an expression, and we don't do any type
19488 adjustments. */
19490 {
19492 {
19495 {
19496 /* [temp.deduct.type] A template-argument can be
19497 deduced from a pointer to function or pointer
19498 to member function argument if the set of
19499 overloaded functions does not contain function
19500 templates and at most one of a set of
19501 overloaded functions provides a unique
19502 match. */
19506 /* If a unique match was not found, this is a
19507 non-deduced context, so we still succeed. */
19509 }
19515 }
19517 arg_strict |=
19519 }
19520 else
19525 /* For deduction from an init-list we need the actual list. */
19529 }
19531 /* for_each_template_parm callback that always returns 0. */
19533 static int
19535 {
19537 }
19539 /* for_each_template_parm any_fn callback to handle deduction of a template
19540 type argument from the type of an array bound. */
19542 static int
19544 {
19552 {
19558 }
19560 /* Keep walking. */
19562 }
19564 /* Try to deduce any not-yet-deduced template type arguments from the type of
19565 an array bound. This is handled separately from unify because 14.8.2.5 says
19566 "The type of a type parameter is only deduced from an array bound if it is
19567 not otherwise deduced." */
19569 static void
19571 {
19576 }
19578 /* Most parms like fn_type_unification.
19580 If SUBR is 1, we're being called recursively (to unify the
19581 arguments of a function or method parameter of a function
19582 template).
19584 CHECKS is a pointer to a vector of access checks encountered while
19585 substituting default template arguments. */
19587 static int
19589 tree full_targs,
19590 tree xparms,
19594 unification_kind_t strict,
19598 {
19603 tree parms;
19614 /* Reset the number of non-defaulted template arguments contained
19615 in TARGS. */
19618 again:
19626 {
19631 /* For a function parameter pack that occurs at the end of the
19632 parameter-declaration-list, the type A of each remaining
19633 argument of the call is compared with the type P of the
19634 declarator-id of the function parameter pack. */
19640 /* For a function parameter pack that does not occur at the
19641 end of the parameter-declaration-list, the type of the
19642 parameter pack is a non-deduced context. */
19649 explain_p))
19651 }
19656 {
19657 /* Unify the remaining arguments with the pack expansion type. */
19658 tree argvec;
19661 /* Allocate a TREE_VEC and copy in all of the arguments */
19666 /* Copy the parameter into parmvec. */
19672 /* Advance to the end of the list of parameters. */
19674 }
19676 /* Fail if we've reached the end of the parm list, and more args
19677 are present, and the parm list isn't variadic. */
19680 /* Fail if parms are left and they don't have default values and
19681 they aren't all deduced as empty packs (c++/57397). This is
19682 consistent with sufficient_parms_p. */
19685 {
19689 do
19690 {
19693 count++;
19695 }
19699 type_pack_p);
19700 }
19703 {
19704 tsubst_flags_t complain = (explain_p
19705 ? tf_warning_or_error
19710 {
19714 /* Clear the "incomplete" flags on all argument packs now so that
19715 substituting them into later default arguments works. */
19717 {
19720 }
19728 {
19733 }
19735 /* If this is an undeduced nontype parameter that depends on
19736 a type parameter, try another pass; its type may have been
19737 deduced from a later argument than the one from which
19738 this parameter can be deduced. */
19742 {
19745 }
19747 /* Core issue #226 (C++0x) [temp.deduct]:
19749 If a template argument has not been deduced, its
19750 default template argument, if any, is used.
19752 When we are in C++98 mode, TREE_PURPOSE will either
19753 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19754 to explicitly check cxx_dialect here. */
19756 /* OK, there is a default argument. Wait until after the
19757 conversion check to do substitution. */
19760 /* If the type parameter is a parameter pack, then it will
19761 be deduced to an empty parameter pack. */
19763 {
19764 tree arg;
19767 {
19770 }
19771 else
19778 }
19781 }
19783 /* DR 1391: All parameters have args, now check non-dependent parms for
19784 convertibility. */
19788 {
19794 /* For a function parameter pack that occurs at the end of the
19795 parameter-declaration-list, the type A of each remaining
19796 argument of the call is compared with the type P of the
19797 declarator-id of the function parameter pack. */
19803 /* For a function parameter pack that does not occur at the
19804 end of the parameter-declaration-list, the type of the
19805 parameter pack is a non-deduced context. */
19814 explain_p))
19816 }
19818 /* Now substitute into the default template arguments. */
19820 {
19844 else
19852 {
19854 /* The position of the first default template argument,
19855 is also the number of non-defaulted arguments in TARGS.
19856 Record that. */
19859 }
19860 }
19864 }
19870 }
19872 /* Subroutine of type_unification_real. Args are like the variables
19873 at the call site. ARG is an overloaded function (or template-id);
19874 we try deducing template args from each of the overloads, and if
19875 only one succeeds, we go with that. Modifies TARGS and returns
19876 true on success. */
19878 static bool
19880 tree targs,
19881 tree parm,
19882 tree arg,
19883 unification_kind_t strict,
19886 {
19893 {
19896 }
19897 else
19901 /* Handle `&x' where `x' is some static or non-static member
19902 function name. */
19908 /* Strip baselink information. */
19913 {
19914 /* If we got some explicit template args, we need to plug them into
19915 the affected templates before we try to unify, in case the
19916 explicit args will completely resolve the templates in question. */
19923 {
19936 {
19941 {
19944 }
19945 }
19948 }
19949 /* If no templates (or more than one) are fully resolved by the
19950 explicit arguments, this template-id is a non-deduced context; it
19951 could still be OK if we deduce all template arguments for the
19952 enclosing call through other arguments. */
19955 }
19958 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19959 -- but the deduction does not succeed because the expression is
19960 not just the function on its own. */
19962 else
19964 {
19969 {
19972 }
19973 }
19975 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19976 to function or pointer to member function argument if the set of
19977 overloaded functions does not contain function templates and at most
19978 one of a set of overloaded functions provides a unique match.
19980 So if we found multiple possibilities, we return success but don't
19981 deduce anything. */
19984 {
19988 {
19993 /* Don't forget explicit template arguments in a pack. */
19997 }
19998 }
20003 }
20005 /* Core DR 115: In contexts where deduction is done and fails, or in
20006 contexts where deduction is not done, if a template argument list is
20007 specified and it, along with any default template arguments, identifies
20008 a single function template specialization, then the template-id is an
20009 lvalue for the function template specialization. */
20011 tree
20013 {
20026 {
20029 }
20031 {
20034 }
20036 {
20039 }
20042 {
20046 /* If we got some explicit template args, we need to plug them into
20047 the affected templates before we try to unify, in case the
20048 explicit args will completely resolve the templates in question. */
20056 {
20069 {
20072 {
20075 }
20077 {
20080 }
20081 }
20082 }
20084 {
20092 {
20093 tree base
20096 }
20100 }
20102 /* There were no good options and at least one bad one, so let the
20103 user know what the problem is. */
20105 }
20107 }
20109 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20110 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20111 different overloads deduce different arguments for a given parm.
20112 ADDR_P is true if the expression for which deduction is being
20113 performed was of the form "& fn" rather than simply "fn".
20115 Returns 1 on success. */
20117 static int
20119 tree orig_targs,
20120 tree targs,
20121 tree parm,
20122 tree arg,
20123 unification_kind_t strict,
20127 {
20129 tree tempargs;
20135 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20136 to function or pointer to member function argument if the set of
20137 overloaded functions does not contain function templates and at most
20138 one of a set of overloaded functions provides a unique match.
20140 So if this is a template, just return success. */
20152 /* We don't copy orig_targs for this because if we have already deduced
20153 some template args from previous args, unify would complain when we
20154 try to deduce a template parameter for the same argument, even though
20155 there isn't really a conflict. */
20162 /* First make sure we didn't deduce anything that conflicts with
20163 explicitly specified args. */
20165 {
20172 /* Since we're unifying against ourselves, we will fill in
20173 template args used in the function parm list with our own
20174 template parms. Discard them. */
20177 {
20178 /* Check that the argument at each index of the deduced argument pack
20179 is equivalent to the corresponding explicitly specified argument.
20180 We may have deduced more arguments than were explicitly specified,
20181 and that's OK. */
20183 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20184 that's wrong if we deduce the same argument pack from multiple
20185 function arguments: it's only incomplete the first time. */
20198 }
20201 }
20204 {
20209 }
20212 }
20214 /* PARM is a template class (perhaps with unbound template
20215 parameters). ARG is a fully instantiated type. If ARG can be
20216 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20217 TARGS are as for unify. */
20219 static tree
20222 {
20223 tree copy_of_targs;
20233 /* We need to make a new template argument vector for the call to
20234 unify. If we used TARGS, we'd clutter it up with the result of
20235 the attempted unification, even if this class didn't work out.
20236 We also don't want to commit ourselves to all the unifications
20237 we've already done, since unification is supposed to be done on
20238 an argument-by-argument basis. In other words, consider the
20239 following pathological case:
20241 template <int I, int J, int K>
20242 struct S {};
20244 template <int I, int J>
20245 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20247 template <int I, int J, int K>
20248 void f(S<I, J, K>, S<I, I, I>);
20250 void g() {
20251 S<0, 0, 0> s0;
20252 S<0, 1, 2> s2;
20254 f(s0, s2);
20255 }
20257 Now, by the time we consider the unification involving `s2', we
20258 already know that we must have `f<0, 0, 0>'. But, even though
20259 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20260 because there are two ways to unify base classes of S<0, 1, 2>
20261 with S<I, I, I>. If we kept the already deduced knowledge, we
20262 would reject the possibility I=1. */
20266 {
20270 }
20272 /* If unification failed, we're done. */
20278 }
20280 /* Given a template type PARM and a class type ARG, find the unique
20281 base type in ARG that is an instance of PARM. We do not examine
20282 ARG itself; only its base-classes. If there is not exactly one
20283 appropriate base class, return NULL_TREE. PARM may be the type of
20284 a partial specialization, as well as a plain template type. Used
20285 by unify. */
20287 static enum template_base_result
20290 {
20292 tree binfo;
20298 {
20299 /* The type could not be completed. */
20302 }
20304 /* Walk in inheritance graph order. The search order is not
20305 important, and this avoids multiple walks of virtual bases. */
20307 {
20312 {
20313 /* If there is more than one satisfactory baseclass, then:
20315 [temp.deduct.call]
20317 If they yield more than one possible deduced A, the type
20318 deduction fails.
20320 applies. */
20322 {
20325 }
20328 }
20329 }
20333 }
20335 /* Returns the level of DECL, which declares a template parameter. */
20337 static int
20339 {
20341 {
20351 }
20353 }
20355 /* Decide whether ARG can be unified with PARM, considering only the
20356 cv-qualifiers of each type, given STRICT as documented for unify.
20357 Returns nonzero iff the unification is OK on that basis. */
20359 static int
20361 {
20367 {
20368 /* Although a CVR qualifier is ignored when being applied to a
20369 substituted template parameter ([8.3.2]/1 for example), that
20370 does not allow us to unify "const T" with "int&" because both
20371 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20372 It is ok when we're allowing additional CV qualifiers
20373 at the outer level [14.8.2.1]/3,1st bullet. */
20383 }
20394 }
20396 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20397 void
20399 {
20403 {
20406 }
20407 else
20408 {
20411 }
20412 }
20414 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20415 do { \
20416 if (unify (TP, TA, P, A, S, EP)) \
20417 return 1; \
20418 } while (0)
20420 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20421 expansion at the end of PACKED_PARMS. Returns 0 if the type
20422 deduction succeeds, 1 otherwise. STRICT is the same as in
20423 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20424 function call argument list. We'll need to adjust the arguments to make them
20425 types. SUBR tells us if this is from a recursive call to
20426 type_unification_real, or for comparing two template argument
20427 lists. */
20429 static int
20433 {
20434 tree parm
20440 /* Add in any args remembered from an earlier partial instantiation. */
20448 /* Determine the parameter packs we will be deducing from the
20449 pattern, and record their current deductions. */
20452 {
20456 /* Determine the index and level of this parameter pack. */
20461 /* Keep track of the parameter packs and their corresponding
20462 argument packs. */
20465 }
20467 /* Loop through all of the arguments that have not yet been
20468 unified and unify each with the pattern. */
20470 {
20471 tree parm;
20475 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20476 or the element of its argument pack at the current index if
20477 this argument was explicitly specified. */
20479 {
20488 {
20491 }
20493 }
20495 /* If we had explicit template arguments, substitute them into the
20496 pattern before deduction. */
20498 {
20499 /* Some arguments might still be unspecified or dependent. */
20507 NULL_TREE);
20512 }
20513 else
20516 /* Unify the pattern with the current argument. */
20518 explain_p))
20521 /* For each parameter pack, collect the deduced value. */
20523 {
20529 }
20530 }
20532 /* Verify that the results of unification with the parameter packs
20533 produce results consistent with what we've seen before, and make
20534 the deduced argument packs available. */
20536 {
20543 /* By default keep the original deduced argument pack.
20544 If necessary, more specific code is going to update the
20545 resulting deduced argument later down in this function. */
20549 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20550 actually deduce anything. */
20558 {
20559 /* If we had fewer function args than explicit template args,
20560 just use the explicits. */
20565 }
20568 {
20569 tree result;
20570 /* Build the deduced *_ARGUMENT_PACK. */
20572 {
20575 }
20576 else
20581 /* Note the deduced argument packs for this parameter
20582 pack. */
20584 }
20588 {
20589 /* We only had the explicitly-provided arguments before, but
20590 now we have a complete set of arguments. */
20596 }
20597 else
20598 {
20604 /* Inconsistent unification of this parameter pack. */
20606 bad_old_arg,
20607 bad_new_arg);
20608 }
20609 }
20612 }
20614 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20615 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20616 parameters and return value are as for unify. */
20618 static int
20622 {
20623 tree parm_max;
20624 tree arg_max;
20628 /* Our representation of array types uses "N - 1" as the
20629 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20630 not an integer constant. We cannot unify arbitrarily
20631 complex expressions, so we eliminate the MINUS_EXPRs
20632 here. */
20636 {
20639 }
20643 {
20644 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20645 trying to unify the type of a variable with the type
20646 of a template parameter. For example:
20648 template <unsigned int N>
20649 void f (char (&) [N]);
20650 int g();
20651 void h(int i) {
20652 char a[g(i)];
20653 f(a);
20654 }
20656 Here, the type of the ARG will be "int [g(i)]", and
20657 may be a SAVE_EXPR, etc. */
20661 }
20663 /* If only one of the bounds used a MINUS_EXPR, compensate
20664 by adding one to the other bound. */
20667 integer_type_node,
20668 parm_max,
20669 integer_one_node);
20672 integer_type_node,
20673 arg_max,
20674 integer_one_node);
20678 }
20680 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20684 static pa_kind_t
20686 {
20695 else
20697 }
20699 /* Deduce the value of template parameters. TPARMS is the (innermost)
20700 set of template parameters to a template. TARGS is the bindings
20701 for those template parameters, as determined thus far; TARGS may
20702 include template arguments for outer levels of template parameters
20703 as well. PARM is a parameter to a template function, or a
20704 subcomponent of that parameter; ARG is the corresponding argument.
20705 This function attempts to match PARM with ARG in a manner
20706 consistent with the existing assignments in TARGS. If more values
20707 are deduced, then TARGS is updated.
20709 Returns 0 if the type deduction succeeds, 1 otherwise. The
20710 parameter STRICT is a bitwise or of the following flags:
20712 UNIFY_ALLOW_NONE:
20713 Require an exact match between PARM and ARG.
20714 UNIFY_ALLOW_MORE_CV_QUAL:
20715 Allow the deduced ARG to be more cv-qualified (by qualification
20716 conversion) than ARG.
20717 UNIFY_ALLOW_LESS_CV_QUAL:
20718 Allow the deduced ARG to be less cv-qualified than ARG.
20719 UNIFY_ALLOW_DERIVED:
20720 Allow the deduced ARG to be a template base class of ARG,
20721 or a pointer to a template base class of the type pointed to by
20722 ARG.
20723 UNIFY_ALLOW_INTEGER:
20724 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20725 case for more information.
20726 UNIFY_ALLOW_OUTER_LEVEL:
20727 This is the outermost level of a deduction. Used to determine validity
20728 of qualification conversions. A valid qualification conversion must
20729 have const qualified pointers leading up to the inner type which
20730 requires additional CV quals, except at the outer level, where const
20731 is not required [conv.qual]. It would be normal to set this flag in
20732 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20733 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20734 This is the outermost level of a deduction, and PARM can be more CV
20735 qualified at this point.
20736 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20737 This is the outermost level of a deduction, and PARM can be less CV
20738 qualified at this point. */
20740 static int
20743 {
20745 tree targ;
20746 tree tparm;
20748 tsubst_flags_t complain = (explain_p
20749 ? tf_warning_or_error
20752 /* I don't think this will do the right thing with respect to types.
20753 But the only case I've seen it in so far has been array bounds, where
20754 signedness is the only information lost, and I think that will be
20755 okay. */
20763 /* We can't deduce anything from this, but we might get all the
20764 template args from other function args. */
20770 /* If PARM uses template parameters, then we can't bail out here,
20771 even if ARG == PARM, since we won't record unifications for the
20772 template parameters. We might need them if we're trying to
20773 figure out which of two things is more specialized. */
20777 /* Handle init lists early, so the rest of the function can assume
20778 we're dealing with a type. */
20780 {
20785 /* Replace T with std::initializer_list<T> for deduction. */
20792 /* We can only deduce from an initializer list argument if the
20793 parameter is std::initializer_list or an array; otherwise this
20794 is a non-deduced context. */
20799 else
20800 {
20802 /* Deduction is defined in terms of a single type, so just punt
20803 on the (bizarre) std::initializer_list<T...>. */
20806 }
20809 {
20816 {
20820 /* It should only be possible to get here for a call. */
20822 elt_strict |= maybe_adjust_types_for_deduction
20825 }
20828 explain_p);
20829 }
20833 {
20834 /* Also deduce from the length of the initializer list. */
20841 }
20843 /* If the std::initializer_list<T> deduction worked, replace the
20844 deduced A with std::initializer_list<A>. */
20846 {
20851 }
20853 }
20855 /* If parm and arg aren't the same kind of thing (template, type, or
20856 expression), fail early. */
20860 /* Immediately reject some pairs that won't unify because of
20861 cv-qualification mismatches. */
20864 /* It is the elements of the array which hold the cv quals of an array
20865 type, and the elements might be template type parms. We'll check
20866 when we recurse. */
20868 /* We check the cv-qualifiers when unifying with template type
20869 parameters below. We want to allow ARG `const T' to unify with
20870 PARM `T' for example, when computing which of two templates
20871 is more specialized, for example. */
20885 {
20889 /* In a type which contains a nested-name-specifier, template
20890 argument values cannot be deduced for template parameters used
20891 within the nested-name-specifier. */
20903 /* The PARM is not one we're trying to unify. Just check
20904 to see if it matches ARG. */
20905 {
20910 else
20912 }
20919 /* Check for mixed types and values. */
20927 {
20930 {
20931 /* First try to match ARG directly. */
20933 explain_p);
20935 {
20936 /* Otherwise, look for a suitable base of ARG, as below. */
20943 }
20944 }
20945 /* ARG must be constructed from a template class or a template
20946 template parameter. */
20951 /* Deduce arguments T, i from TT<T> or TT<i>. */
20957 /* Fall through to deduce template name. */
20958 }
20962 {
20963 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20965 /* Simple cases: Value already set, does match or doesn't. */
20970 }
20971 else
20972 {
20973 /* If PARM is `const T' and ARG is only `int', we don't have
20974 a match unless we are allowing additional qualification.
20975 If ARG is `const int' and PARM is just `T' that's OK;
20976 that binds `const int' to `T'. */
20981 /* Consider the case where ARG is `const volatile int' and
20982 PARM is `const T'. Then, T should be `volatile int'. */
20983 arg = cp_build_qualified_type_real
20988 /* Simple cases: Value already set, does match or doesn't. */
20994 /* Make sure that ARG is not a variable-sized array. (Note
20995 that were talking about variable-sized arrays (like
20996 `int[n]'), rather than arrays of unknown size (like
20997 `int[]').) We'll get very confused by such a type since
20998 the bound of the array is not constant, and therefore
20999 not mangleable. Besides, such types are not allowed in
21000 ISO C++, so we can do as we please here. We do allow
21001 them for 'auto' deduction, since that isn't ABI-exposed. */
21005 /* Strip typedefs as in convert_template_argument. */
21007 }
21009 /* If ARG is a parameter pack or an expansion, we cannot unify
21010 against it unless PARM is also a parameter pack. */
21015 /* If the argument deduction results is a METHOD_TYPE,
21016 then there is a problem.
21017 METHOD_TYPE doesn't map to any real C++ type the result of
21018 the deduction can not be of that type. */
21032 {
21033 /* The PARM is not one we're trying to unify. Just check
21034 to see if it matches ARG. */
21040 }
21046 {
21050 /* We're deducing from an array bound, the type doesn't matter. */
21056 }
21058 /* [temp.deduct.type] If, in the declaration of a function template
21059 with a non-type template-parameter, the non-type
21060 template-parameter is used in an expression in the function
21061 parameter-list and, if the corresponding template-argument is
21062 deduced, the template-argument type shall match the type of the
21063 template-parameter exactly, except that a template-argument
21064 deduced from an array bound may be of any integral type.
21065 The non-type parameter might use already deduced type parameters. */
21070 {
21074 }
21077 /* Template-parameter dependent expression. Just accept it for now.
21078 It will later be processed in convert_template_argument. */
21079 ;
21085 /* Convert the ARG to the type of PARM; the deduced non-type
21086 template argument must exactly match the types of the
21087 corresponding parameter. */
21090 {
21091 /* We haven't deduced the type of this parameter yet. */
21093 /* We deduce from array bounds in try_array_deduction. */
21095 {
21096 /* Deduce it from the non-type argument. */
21101 }
21102 else
21103 /* Try again later. */
21105 }
21106 else
21109 /* If ARG is a parameter pack or an expansion, we cannot unify
21110 against it unless PARM is also a parameter pack. */
21115 {
21118 }
21123 {
21124 /* A pointer-to-member constant can be unified only with
21125 another constant. */
21129 /* Just unify the class member. It would be useless (and possibly
21130 wrong, depending on the strict flags) to unify also
21131 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21132 arg refer to the same variable, even if through different
21133 classes. For instance:
21135 struct A { int x; };
21136 struct B : A { };
21138 Unification of &A::x and &B::x must succeed. */
21141 }
21144 {
21148 /* [temp.deduct.call]
21150 A can be another pointer or pointer to member type that can
21151 be converted to the deduced A via a qualification
21152 conversion (_conv.qual_).
21154 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21155 This will allow for additional cv-qualification of the
21156 pointed-to types if appropriate. */
21159 /* The derived-to-base conversion only persists through one
21160 level of pointers. */
21165 }
21197 /* We have already checked cv-qualification at the top of the
21198 function. */
21202 /* As far as unification is concerned, this wins. Later checks
21203 will invalidate it if necessary. */
21206 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21207 /* Type INTEGER_CST can come from ordinary constant template args. */
21219 {
21229 /* Check for pack expansions in the parameters. */
21231 {
21233 {
21235 /* We can unify against something with a trailing
21236 parameter pack. */
21238 else
21239 /* [temp.deduct.type]/9: If the template argument list of
21240 P contains a pack expansion that is not the last
21241 template argument, the entire template argument list
21242 is a non-deduced context. */
21244 }
21245 }
21247 /* If we don't have enough arguments to satisfy the parameters
21248 (not counting the pack expression at the end), or we have
21249 too many arguments for a parameter list that doesn't end in
21250 a pack expression, we can't unify. */
21256 /* Unify all of the parameters that precede the (optional)
21257 pack expression. */
21259 {
21264 }
21267 DEDUCE_EXACT,
21270 }
21278 {
21286 }
21291 {
21295 {
21296 /* First, we try to unify the PARM and ARG directly. */
21301 {
21302 /* Fallback to the special case allowed in
21303 [temp.deduct.call]:
21305 If P is a class, and P has the form
21306 template-id, then A can be a derived class of
21307 the deduced A. Likewise, if P is a pointer to
21308 a class of the form template-id, A can be a
21309 pointer to a derived class pointed to by the
21310 deduced A. */
21316 {
21317 /* Don't give the derived diagnostic if we're
21318 already dealing with the same template. */
21319 bool same_template
21325 }
21326 }
21327 }
21331 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21332 Then, we should unify `int' and `U'. */
21334 else
21335 /* There's no chance of unification succeeding. */
21340 }
21347 {
21350 tree a;
21356 /* CV qualifications for methods can never be deduced, they must
21357 match exactly. We need to check them explicitly here,
21358 because type_unification_real treats them as any other
21359 cv-qualified parameter. */
21361 && (!check_cv_quals_for_unify
21389 {
21401 }
21404 }
21407 /* Unify a pointer to member with a pointer to member function, which
21408 deduces the type of the member as a function type. */
21410 {
21411 /* Check top-level cv qualifiers */
21419 /* Determine the type of the function we are unifying against. */
21423 }
21442 /* Matched cases are handled by the ARG == PARM test above. */
21446 /* We might get a variable as a non-type template argument in parm if the
21447 corresponding parameter is type-dependent. Make any necessary
21448 adjustments based on whether arg is a reference. */
21452 {
21457 }
21458 /* Now use the normal expression code to check whether they match. */
21469 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21470 or UNDERLYING_TYPE nodes. */
21474 /* Unification fails if we hit an error node. */
21479 {
21489 }
21490 /* FALLTHRU */
21493 /* An unresolved overload is a nondeduced context. */
21497 expr:
21498 /* We must be looking at an expression. This can happen with
21499 something like:
21501 template <int I>
21502 void foo(S<I>, S<I + 2>);
21504 This is a "nondeduced context":
21506 [deduct.type]
21508 The nondeduced contexts are:
21510 --A type that is a template-id in which one or more of
21511 the template-arguments is an expression that references
21512 a template-parameter.
21514 In these cases, we assume deduction succeeded, but don't
21515 actually infer any unifications. */
21520 else
21522 }
21523 }
21524 #undef RECUR_AND_CHECK_FAILURE
21525 \f
21526 /* Note that DECL can be defined in this translation unit, if
21527 required. */
21529 static void
21531 {
21532 tree clone;
21536 }
21538 /* Called if RESULT is explicitly instantiated, or is a member of an
21539 explicitly instantiated class. */
21541 void
21543 {
21546 /* If this entity has already been written out, it's too late to
21547 make any modifications. */
21551 /* For anonymous namespace we don't need to do anything. */
21553 {
21556 }
21559 /* The TREE_PUBLIC flag for function declarations will have been
21560 set correctly by tsubst. */
21563 /* This might have been set by an earlier implicit instantiation. */
21568 else
21569 {
21572 /* Always make artificials weak. */
21575 /* For WIN32 we also want to put explicit instantiations in
21576 linkonce sections. */
21579 }
21581 /* If EXTERN_P, then this function will not be emitted -- unless
21582 followed by an explicit instantiation, at which point its linkage
21583 will be adjusted. If !EXTERN_P, then this function will be
21584 emitted here. In neither circumstance do we want
21585 import_export_decl to adjust the linkage. */
21587 }
21589 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21590 important template arguments. If any are missing, we check whether
21591 they're important by using error_mark_node for substituting into any
21592 args that were used for partial ordering (the ones between ARGS and END)
21593 and seeing if it bubbles up. */
21595 static bool
21597 {
21602 {
21605 }
21607 {
21611 }
21613 }
21615 /* Given two function templates PAT1 and PAT2, return:
21617 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21618 -1 if PAT2 is more specialized than PAT1.
21619 0 if neither is more specialized.
21621 LEN indicates the number of parameters we should consider
21622 (defaulted parameters should not be considered).
21624 The 1998 std underspecified function template partial ordering, and
21625 DR214 addresses the issue. We take pairs of arguments, one from
21626 each of the templates, and deduce them against each other. One of
21627 the templates will be more specialized if all the *other*
21628 template's arguments deduce against its arguments and at least one
21629 of its arguments *does* *not* deduce against the other template's
21630 corresponding argument. Deduction is done as for class templates.
21631 The arguments used in deduction have reference and top level cv
21632 qualifiers removed. Iff both arguments were originally reference
21633 types *and* deduction succeeds in both directions, an lvalue reference
21634 wins against an rvalue reference and otherwise the template
21635 with the more cv-qualified argument wins for that pairing (if
21636 neither is more cv-qualified, they both are equal). Unlike regular
21637 deduction, after all the arguments have been deduced in this way,
21638 we do *not* verify the deduced template argument values can be
21639 substituted into non-deduced contexts.
21641 The logic can be a bit confusing here, because we look at deduce1 and
21642 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21643 can find template arguments for pat1 to make arg1 look like arg2, that
21644 means that arg2 is at least as specialized as arg1. */
21646 int
21648 {
21661 /* Remove the this parameter from non-static member functions. If
21662 one is a non-static member function and the other is not a static
21663 member function, remove the first parameter from that function
21664 also. This situation occurs for operator functions where we
21665 locate both a member function (with this pointer) and non-member
21666 operator (with explicit first operand). */
21668 {
21673 }
21675 {
21678 {
21679 len--;
21681 }
21682 }
21684 /* If only one is a conversion operator, they are unordered. */
21688 /* Consider the return type for a conversion function */
21690 {
21693 len++;
21694 }
21696 processing_template_decl++;
21702 /* Stop when an ellipsis is seen. */
21704 {
21715 {
21716 /* When both arguments are pack expansions, we need only
21717 unify the patterns themselves. */
21721 /* This is the last comparison we need to do. */
21723 }
21725 /* DR 1847: If a particular P contains no template-parameters that
21726 participate in template argument deduction, that P is not used to
21727 determine the ordering. */
21733 {
21737 }
21740 {
21744 }
21750 {
21756 /* Setup the parameter vector, which contains only ARG1. */
21759 /* Setup the argument vector, which contains the remaining
21760 arguments. */
21769 /* We cannot deduce in the other direction, because ARG1 is
21770 a pack expansion but ARG2 is not. */
21772 }
21774 {
21780 /* Setup the parameter vector, which contains only ARG1. */
21783 /* Setup the argument vector, which contains the remaining
21784 arguments. */
21793 /* We cannot deduce in the other direction, because ARG2 is
21794 a pack expansion but ARG1 is not.*/
21796 }
21798 else
21799 {
21800 /* The normal case, where neither argument is a pack
21801 expansion. */
21808 }
21810 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21811 arg2, then arg2 is not as specialized as arg1. */
21817 /* "If, for a given type, deduction succeeds in both directions
21818 (i.e., the types are identical after the transformations above)
21819 and both P and A were reference types (before being replaced with
21820 the type referred to above):
21821 - if the type from the argument template was an lvalue reference and
21822 the type from the parameter template was not, the argument type is
21823 considered to be more specialized than the other; otherwise,
21824 - if the type from the argument template is more cv-qualified
21825 than the type from the parameter template (as described above),
21826 the argument type is considered to be more specialized than the other;
21827 otherwise,
21828 - neither type is more specialized than the other." */
21831 {
21833 {
21836 else
21838 }
21840 {
21845 }
21846 }
21849 /* We've failed to deduce something in either direction.
21850 These must be unordered. */
21853 next:
21857 /* We have already processed all of the arguments in our
21858 handing of the pack expansion type. */
21863 }
21865 /* "In most cases, all template parameters must have values in order for
21866 deduction to succeed, but for partial ordering purposes a template
21867 parameter may remain without a value provided it is not used in the
21868 types being used for partial ordering."
21870 Thus, if we are missing any of the targs1 we need to substitute into
21871 origs1, then pat2 is not as specialized as pat1. This can happen when
21872 there is a nondeduced context. */
21878 processing_template_decl--;
21880 /* If both deductions succeed, the partial ordering selects the more
21881 constrained template. */
21883 {
21888 }
21890 /* All things being equal, if the next argument is a pack expansion
21891 for one function but not for the other, prefer the
21892 non-variadic function. FIXME this is bogus; see c++/41958. */
21896 {
21899 }
21905 else
21907 }
21909 /* Determine which of two partial specializations of TMPL is more
21910 specialized.
21912 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21913 to the first partial specialization. The TREE_PURPOSE is the
21914 innermost set of template parameters for the partial
21915 specialization. PAT2 is similar, but for the second template.
21917 Return 1 if the first partial specialization is more specialized;
21918 -1 if the second is more specialized; 0 if neither is more
21919 specialized.
21921 See [temp.class.order] for information about determining which of
21922 two templates is more specialized. */
21924 static int
21926 {
21927 tree targs;
21936 /* Just like what happens for functions, if we are ordering between
21937 different template specializations, we may encounter dependent
21938 types in the arguments, and we need our dependency check functions
21939 to behave correctly. */
21943 {
21946 }
21950 {
21953 }
21956 /* If both deductions succeed, the partial ordering selects the more
21957 constrained template. */
21961 /* In the case of a tie where at least one of the templates
21962 has a parameter pack at the end, the template with the most
21963 non-packed parameters wins. */
21965 && any_deductions
21968 {
21974 /* We don't count the pack expansion at the end. */
21984 }
21987 }
21989 /* Return the template arguments that will produce the function signature
21990 DECL from the function template FN, with the explicit template
21991 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21992 also match. Return NULL_TREE if no satisfactory arguments could be
21993 found. */
21995 static tree
21997 {
22001 tree decl_arg_types;
22004 tree arg;
22008 /* Never do unification on the 'this' parameter. */
22029 }
22031 /* Return the innermost template arguments that, when applied to a partial
22032 specialization SPEC_TMPL of TMPL, yield the ARGS.
22034 For example, suppose we have:
22036 template <class T, class U> struct S {};
22037 template <class T> struct S<T*, int> {};
22039 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22040 partial specialization and the ARGS will be {double*, int}. The resulting
22041 vector will be {double}, indicating that `T' is bound to `double'. */
22043 static tree
22045 {
22047 tree spec_args
22050 tree deduced_args;
22051 tree innermost_deduced_args;
22055 {
22059 innermost_deduced_args);
22060 }
22061 else
22065 again:
22074 {
22076 {
22082 }
22084 }
22088 {
22091 }
22093 /* Verify that nondeduced template arguments agree with the type
22094 obtained from argument deduction.
22096 For example:
22098 struct A { typedef int X; };
22099 template <class T, class U> struct C {};
22100 template <class T> struct C<T, typename T::X> {};
22102 Then with the instantiation `C<A, int>', we can deduce that
22103 `T' is `A' but unify () does not check whether `typename T::X'
22104 is `int'. */
22115 /* We only need to check the innermost arguments; the other
22116 arguments will always agree. */
22121 /* Now that we have bindings for all of the template arguments,
22122 ensure that the arguments deduced for the template template
22123 parameters have compatible template parameter lists. See the use
22124 of template_template_parm_bindings_ok_p in fn_type_unification
22125 for more information. */
22130 }
22132 // Compare two function templates T1 and T2 by deducing bindings
22133 // from one against the other. If both deductions succeed, compare
22134 // constraints to see which is more constrained.
22135 static int
22137 {
22142 {
22145 }
22148 {
22151 }
22153 // If both deductions succeed, then one may be more constrained.
22158 }
22160 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22161 Return the TREE_LIST node with the most specialized template, if
22162 any. If there is no most specialized template, the error_mark_node
22163 is returned.
22165 Note that this function does not look at, or modify, the
22166 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22167 returned is one of the elements of INSTANTIATIONS, callers may
22168 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22169 and retrieve it from the value returned. */
22171 tree
22173 {
22180 {
22186 {
22187 /* Equally specialized, move to next function. If there
22188 is no next function, nothing's most specialized. */
22193 }
22194 }
22197 /* Now verify that champ is better than everything earlier in the
22198 instantiation list. */
22201 {
22204 }
22205 }
22207 processing_template_decl--;
22213 }
22215 /* If DECL is a specialization of some template, return the most
22216 general such template. Otherwise, returns NULL_TREE.
22218 For example, given:
22220 template <class T> struct S { template <class U> void f(U); };
22222 if TMPL is `template <class U> void S<int>::f(U)' this will return
22223 the full template. This function will not trace past partial
22224 specializations, however. For example, given in addition:
22226 template <class T> struct S<T*> { template <class U> void f(U); };
22228 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22229 `template <class T> template <class U> S<T*>::f(U)'. */
22231 tree
22233 {
22235 {
22238 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22239 template friend, or a FIELD_DECL for a capture pack. */
22242 }
22244 /* Look for more and more general templates. */
22246 {
22247 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22248 (See cp-tree.h for details.) */
22257 /* Stop if we run into an explicitly specialized class template. */
22264 }
22267 }
22269 /* Return the most specialized of the template partial specializations
22270 which can produce TARGET, a specialization of some class or variable
22271 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22272 a TEMPLATE_DECL node corresponding to the partial specialization, while
22273 the TREE_PURPOSE is the set of template arguments that must be
22274 substituted into the template pattern in order to generate TARGET.
22276 If the choice of partial specialization is ambiguous, a diagnostic
22277 is issued, and the error_mark_node is returned. If there are no
22278 partial specializations matching TARGET, then NULL_TREE is
22279 returned, indicating that the primary template should be used. */
22281 static tree
22283 {
22285 tree t;
22286 tree champ;
22293 {
22297 }
22299 {
22302 }
22304 {
22308 }
22309 else
22314 /* For determining which partial specialization to use, only the
22315 innermost args are interesting. */
22317 {
22320 }
22323 {
22324 tree spec_args;
22328 {
22329 /* Substitute in the template args from the enclosing class. */
22333 }
22340 {
22344 /* Keep the candidate only if the constraints are satisfied,
22345 or if we're not compiling with concepts. */
22348 {
22351 }
22352 }
22353 }
22363 {
22366 ;
22367 else
22368 {
22370 {
22373 {
22376 }
22377 }
22379 }
22380 }
22384 {
22387 {
22390 }
22391 }
22394 {
22401 else
22405 {
22410 }
22413 }
22416 }
22418 /* Explicitly instantiate DECL. */
22420 void
22422 {
22427 /* An error occurred, for which grokdeclarator has already issued
22428 an appropriate message. */
22431 {
22434 }
22440 {
22441 /* There is an asymmetry here in the way VAR_DECLs and
22442 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22443 the latter, the DECL we get back will be marked as a
22444 template instantiation, and the appropriate
22445 DECL_TEMPLATE_INFO will be set up. This does not happen for
22446 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22447 should handle VAR_DECLs as it currently handles
22448 FUNCTION_DECLs. */
22450 {
22453 }
22456 {
22459 }
22461 {
22466 }
22467 }
22469 {
22472 }
22473 else
22476 /* Check for various error cases. Note that if the explicit
22477 instantiation is valid the RESULT will currently be marked as an
22478 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22479 until we get here. */
22482 {
22483 /* DR 259 [temp.spec].
22485 Both an explicit instantiation and a declaration of an explicit
22486 specialization shall not appear in a program unless the explicit
22487 instantiation follows a declaration of the explicit specialization.
22489 For a given set of template parameters, if an explicit
22490 instantiation of a template appears after a declaration of an
22491 explicit specialization for that template, the explicit
22492 instantiation has no effect. */
22494 }
22496 {
22497 /* [temp.spec]
22499 No program shall explicitly instantiate any template more
22500 than once.
22502 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22503 the first instantiation was `extern' and the second is not,
22504 and EXTERN_P for the opposite case. */
22507 /* If an "extern" explicit instantiation follows an ordinary
22508 explicit instantiation, the template is instantiated. */
22511 }
22513 {
22516 }
22518 {
22521 }
22524 ;
22526 {
22529 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22532 }
22533 else
22541 }
22543 static void
22545 {
22551 {
22554 }
22555 }
22557 /* Called from do_type_instantiation through binding_table_foreach to
22558 do recursive instantiation for the type bound in ENTRY. */
22559 static void
22561 {
22567 }
22569 /* Perform an explicit instantiation of template class T. STORAGE, if
22570 non-null, is the RID for extern, inline or static. COMPLAIN is
22571 nonzero if this is called from the parser, zero if called recursively,
22572 since the standard is unclear (as detailed below). */
22574 void
22576 {
22586 {
22587 tree tmpl =
22591 else
22594 }
22599 {
22602 t);
22604 }
22607 {
22609 {
22611 {
22614 "ISO C++ 1998 forbids the use of %<extern%> on "
22616 }
22617 else
22619 "ISO C++ forbids the use of %qE"
22621 }
22629 else
22630 {
22632 storage);
22634 }
22635 }
22638 {
22639 /* DR 259 [temp.spec].
22641 Both an explicit instantiation and a declaration of an explicit
22642 specialization shall not appear in a program unless the explicit
22643 instantiation follows a declaration of the explicit specialization.
22645 For a given set of template parameters, if an explicit
22646 instantiation of a template appears after a declaration of an
22647 explicit specialization for that template, the explicit
22648 instantiation has no effect. */
22650 }
22652 {
22653 /* [temp.spec]
22655 No program shall explicitly instantiate any template more
22656 than once.
22658 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22659 instantiation was `extern'. If EXTERN_P then the second is.
22660 These cases are OK. */
22667 /* If we've already instantiated the template, just return now. */
22670 }
22678 /* In contrast to implicit instantiation, where only the
22679 declarations, and not the definitions, of members are
22680 instantiated, we have here:
22682 [temp.explicit]
22684 The explicit instantiation of a class template specialization
22685 implies the instantiation of all of its members not
22686 previously explicitly specialized in the translation unit
22687 containing the explicit instantiation.
22689 Of course, we can't instantiate member template classes, since we
22690 don't have any arguments for them. Note that the standard is
22691 unclear on whether the instantiation of the members are
22692 *explicit* instantiations or not. However, the most natural
22693 interpretation is that it should be an explicit
22694 instantiation. */
22698 && !static_p
22701 {
22706 }
22711 }
22713 /* Given a function DECL, which is a specialization of TMPL, modify
22714 DECL to be a re-instantiation of TMPL with the same template
22715 arguments. TMPL should be the template into which tsubst'ing
22716 should occur for DECL, not the most general template.
22718 One reason for doing this is a scenario like this:
22720 template <class T>
22721 void f(const T&, int i);
22723 void g() { f(3, 7); }
22725 template <class T>
22726 void f(const T& t, const int i) { }
22728 Note that when the template is first instantiated, with
22729 instantiate_template, the resulting DECL will have no name for the
22730 first parameter, and the wrong type for the second. So, when we go
22731 to instantiate the DECL, we regenerate it. */
22733 static void
22735 {
22736 /* The arguments used to instantiate DECL, from the most general
22737 template. */
22738 tree code_pattern;
22742 /* Make sure that we can see identifiers, and compute access
22743 correctly. */
22747 {
22748 tree decl_parm;
22749 tree pattern_parm;
22750 tree specs;
22764 specs);
22766 /* Merge parameter declarations. */
22769 pattern_parm
22773 {
22774 tree parm_type;
22775 tree attributes;
22780 NULL_TREE);
22786 {
22789 }
22792 }
22793 /* Merge any parameters that match with the function parameter
22794 pack. */
22796 {
22798 tree expanded_types;
22799 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22800 the parameters in this function parameter pack. */
22805 {
22806 tree parm_type;
22807 tree attributes;
22810 /* Rename the parameter to include the index. */
22819 {
22822 }
22824 }
22825 }
22826 /* Merge additional specifiers from the CODE_PATTERN. */
22830 }
22832 {
22842 }
22843 else
22847 }
22849 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22850 substituted to get DECL. */
22852 tree
22854 {
22857 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22858 for the instantiation. This is not always the most general
22859 template. Consider, for example:
22861 template <class T>
22862 struct S { template <class U> void f();
22863 template <> void f<int>(); };
22865 and an instantiation of S<double>::f<int>. We want TD to be the
22866 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22868 more general template. */
22870 /* We must also deal with friend templates. Given:
22872 template <class T> struct S {
22873 template <class U> friend void f() {};
22874 };
22876 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22877 so far as the language is concerned, but that's still
22878 where we get the pattern for the instantiation from. On
22879 other hand, if the definition comes outside the class, say:
22881 template <class T> struct S {
22882 template <class U> friend void f();
22883 };
22884 template <class U> friend void f() {}
22886 we don't need to look any further. That's what the check for
22887 DECL_INITIAL is for. */
22891 {
22892 /* The present template, TD, should not be a definition. If it
22893 were a definition, we should be using it! Note that we
22894 cannot restructure the loop to just keep going until we find
22895 a template with a definition, since that might go too far if
22896 a specialization was declared, but not defined. */
22898 /* Fetch the more general template. */
22900 }
22903 }
22905 /* Returns true if we need to instantiate this template instance even if we
22906 know we aren't going to emit it. */
22908 bool
22910 {
22911 /* We always instantiate inline functions so that we can inline them. An
22912 explicit instantiation declaration prohibits implicit instantiation of
22913 non-inline functions. With high levels of optimization, we would
22914 normally inline non-inline functions -- but we're not allowed to do
22915 that for "extern template" functions. Therefore, we check
22916 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22920 /* And we need to instantiate static data members so that
22921 their initializers are available in integral constant
22922 expressions. */
22925 }
22927 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22928 instantiate it now, modifying TREE_TYPE (fn). Returns false on
22929 error, true otherwise. */
22931 bool
22933 {
22936 /* Don't instantiate a noexcept-specification from template context. */
22951 {
22957 {
22958 /* If hash_set::add returns true, the element was already there. */
22963 fn);
22965 }
22967 {
22982 }
22983 else
22993 }
22996 {
22999 else
23001 }
23004 }
23006 /* We're starting to process the function INST, an instantiation of PATTERN;
23007 add their parameters to local_specializations. */
23009 static void
23011 {
23015 {
23019 }
23021 {
23023 {
23026 }
23027 else
23028 {
23029 /* Register the (value) argument pack as a specialization of
23030 TMPL_PARM, then move on. */
23033 }
23034 }
23036 }
23038 /* Produce the definition of D, a _DECL generated from a template. If
23039 DEFER_OK is true, then we don't have to actually do the
23040 instantiation now; we just have to do it sometime. Normally it is
23041 an error if this is an explicit instantiation but D is undefined.
23042 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23043 instantiated class template. */
23045 tree
23047 {
23049 tree gen_args;
23050 tree args;
23051 tree td;
23052 tree code_pattern;
23053 tree spec;
23054 tree gen_tmpl;
23062 /* This function should only be used to instantiate templates for
23063 functions and static member variables. */
23066 /* A concept is never instantiated. */
23069 /* Variables are never deferred; if instantiation is required, they
23070 are instantiated right away. That allows for better code in the
23071 case that an expression refers to the value of the variable --
23072 if the variable has a constant value the referring expression can
23073 take advantage of that fact. */
23077 /* Don't instantiate cloned functions. Instead, instantiate the
23078 functions they cloned. */
23086 /* D has already been instantiated or explicitly specialized, so
23087 there's nothing for us to do here.
23089 It might seem reasonable to check whether or not D is an explicit
23090 instantiation, and, if so, stop here. But when an explicit
23091 instantiation is deferred until the end of the compilation,
23092 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23093 the instantiation. */
23096 /* Check to see whether we know that this template will be
23097 instantiated in some other file, as with "extern template"
23098 extension. */
23101 /* In general, we do not instantiate such templates. */
23109 /* We should already have the extra args. */
23112 /* And what's in the hash table should match D. */
23116 /* This needs to happen before any tsubsting. */
23122 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23123 for the instantiation. */
23128 {
23129 /* Look up an explicit specialization, if any. */
23133 {
23136 }
23137 }
23141 /* We should never be trying to instantiate a member of a class
23142 template or partial specialization. */
23147 /* In the case of a friend template whose definition is provided
23148 outside the class, we may have too many arguments. Drop the
23149 ones we don't need. The same is true for specializations. */
23150 args = get_innermost_template_args
23154 {
23160 }
23161 else
23162 {
23167 else
23169 }
23171 /* We may be in the middle of deferred access check. Disable it now. */
23174 /* Unless an explicit instantiation directive has already determined
23175 the linkage of D, remember that a definition is available for
23176 this entity. */
23186 /* If D is a member of an explicitly instantiated class template,
23187 and no definition is available, treat it like an implicit
23188 instantiation. */
23191 {
23192 /* Leave linkage flags alone on instantiations with anonymous
23193 visibility. */
23195 {
23198 }
23200 }
23202 /* Defer all other templates, unless we have been explicitly
23203 forbidden from doing so. */
23205 template. */
23206 ! pattern_defined
23207 /* If it's OK to postpone instantiation, do so. */
23208 || defer_ok
23209 /* If this is a static data member that will be defined
23210 elsewhere, we don't want to instantiate the entire data
23211 member, but we do want to instantiate the initializer so that
23212 we can substitute that elsewhere. */
23214 /* Handle here a deleted function too, avoid generating
23215 its body (c++/61080). */
23217 {
23218 /* The definition of the static data member is now required so
23219 we must substitute the initializer. */
23223 {
23224 tree ns;
23225 tree init;
23234 args,
23237 /* If instantiating the initializer involved instantiating this
23238 again, don't call cp_finish_decl twice. */
23240 {
23241 /* Make sure the initializer is still constant, in case of
23242 circular dependency (template/instantiate6.C). */
23243 const_init
23247 LOOKUP_ONLYCONVERTING);
23248 }
23252 }
23254 /* We restore the source position here because it's used by
23255 add_pending_template. */
23261 /* [temp.explicit]
23263 The definition of a non-exported function template, a
23264 non-exported member function template, or a non-exported
23265 member function or static data member of a class template
23266 shall be present in every translation unit in which it is
23267 explicitly instantiated. */
23271 /* If we're in unevaluated context, we just wanted to get the
23272 constant value; this isn't an odr use, so don't queue
23273 a full instantiation. */
23276 /* ??? Historically, we have instantiated inline functions, even
23277 when marked as "extern template". */
23281 }
23282 /* Tell the repository that D is available in this translation unit
23283 -- and see if it is supposed to be instantiated here. */
23285 {
23286 /* In a PCH file, despite the fact that the repository hasn't
23287 requested instantiation in the PCH it is still possible that
23288 an instantiation will be required in a file that includes the
23289 PCH. */
23292 /* Instantiate inline functions so that the inliner can do its
23293 job, even though we'll not be emitting a copy of this
23294 function. */
23297 }
23300 tree fn_context;
23311 else
23312 {
23316 }
23318 /* Mark D as instantiated so that recursive calls to
23319 instantiate_decl do not try to instantiate it again. */
23322 /* Regenerate the declaration in case the template has been modified
23323 by a subsequent redeclaration. */
23326 /* We already set the file and line above. Reset them now in case
23327 they changed as a result of calling regenerate_decl_from_template. */
23331 {
23332 tree init;
23335 /* Clear out DECL_RTL; whatever was there before may not be right
23336 since we've reset the type of the declaration. */
23340 /* The initializer is placed in DECL_INITIAL by
23341 regenerate_decl_from_template so we don't need to
23342 push/pop_access_scope again here. Pull it out so that
23343 cp_finish_decl can process it. */
23348 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23349 initializer. That function will defer actual emission until
23350 we have a chance to determine linkage. */
23353 /* Enter the scope of D so that access-checking works correctly. */
23366 }
23370 {
23371 /* Set up the list of local specializations. */
23375 /* Set up context. */
23379 else
23382 /* Some typedefs referenced from within the template code need to be
23383 access checked at template instantiation time, i.e now. These
23384 types were added to the template at parsing time. Let's get those
23385 and perform the access checks then. */
23387 args);
23389 /* Create substitution entries for the parameters. */
23392 /* Substitute into the body of the function. */
23396 else
23397 {
23402 /* Set the current input_location to the end of the function
23403 so that finish_function knows where we are. */
23404 input_location
23407 /* Remember if we saw an infinite loop in the template. */
23408 current_function_infinite_loop
23410 }
23412 /* Finish the function. */
23416 else
23417 {
23420 }
23424 }
23426 /* We're not deferring instantiation any more. */
23431 else
23437 out:
23446 }
23448 /* Run through the list of templates that we wish we could
23449 instantiate, and instantiate any we can. RETRIES is the
23450 number of times we retry pending template instantiation. */
23452 void
23454 {
23458 /* Instantiating templates may trigger vtable generation. This in turn
23459 may require further template instantiations. We place a limit here
23460 to avoid infinite loop. */
23462 {
23466 "template instantiation depth exceeds maximum of %d"
23467 " instantiating %q+D, possibly from virtual table generation"
23471 /* Pretend that we defined it. */
23474 }
23476 do
23477 {
23482 {
23487 {
23489 {
23504 }
23507 }
23508 else
23509 {
23512 {
23513 instantiation
23519 }
23523 }
23526 /* If INSTANTIATION has been instantiated, then we don't
23527 need to consider it again in the future. */
23529 else
23530 {
23533 }
23536 }
23538 }
23542 }
23544 /* Substitute ARGVEC into T, which is a list of initializers for
23545 either base class or a non-static data member. The TREE_PURPOSEs
23546 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23547 instantiate_decl. */
23549 static tree
23551 {
23555 {
23556 tree decl;
23557 tree init;
23563 {
23564 tree expr;
23565 tree arg;
23567 /* Expand the base class expansion type into separate base
23568 classes. */
23570 tf_warning_or_error,
23571 NULL_TREE);
23575 /* We'll be building separate TREE_LISTs of arguments for
23576 each base. */
23582 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23583 expand each argument in the TREE_VALUE of t. */
23590 /* VOID_TYPE_NODE is used to indicate
23591 value-initialization. */
23592 {
23595 }
23596 else
23597 {
23598 /* Substitute parameter packs into each argument in the
23599 TREE_LIST. */
23602 {
23603 tree expanded_exprs;
23605 /* Expand the argument. */
23607 expanded_exprs
23609 tf_warning_or_error,
23610 NULL_TREE);
23614 /* Prepend each of the expanded expressions to the
23615 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23617 {
23622 }
23623 }
23626 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23627 since we built them backwards. */
23629 {
23632 }
23633 }
23634 }
23637 {
23639 {
23643 }
23644 else
23645 {
23646 tree tmp;
23661 /* If we had an initializer but it instantiated to nothing,
23662 value-initialize the object. This will only occur when
23663 the initializer was a pack expansion where the parameter
23664 packs used in that expansion were of length zero. */
23667 }
23670 {
23674 }
23675 }
23676 }
23678 }
23680 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23682 static void
23684 {
23689 else
23691 }
23693 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23694 is the instantiation (which should have been created with
23695 start_enum) and ARGS are the template arguments to use. */
23697 static void
23699 {
23700 tree e;
23706 {
23707 tree value;
23708 tree decl;
23711 /* Note that in a template enum, the TREE_VALUE is the
23712 CONST_DECL, not the corresponding INTEGER_CST. */
23717 /* Give this enumeration constant the correct access. */
23720 /* Actually build the enumerator itself. Here we're assuming that
23721 enumerators can't have dependent attributes. */
23724 }
23734 }
23736 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23737 its type -- but without substituting the innermost set of template
23738 arguments. So, innermost set of template parameters will appear in
23739 the type. */
23741 tree
23743 {
23744 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23746 }
23748 /* Return truthvalue if we're processing a template different from
23749 the last one involved in diagnostics. */
23750 bool
23752 {
23754 }
23756 /* Remember current template involved in diagnostics. */
23757 void
23759 {
23761 }
23765 {
23767 }
23769 /* Return TRUE if current_function_decl is being instantiated, false
23770 otherwise. */
23772 bool
23774 {
23777 }
23779 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23780 type. Return false for ok, true for disallowed. Issue error and
23781 inform messages under control of COMPLAIN. */
23783 static bool
23785 {
23800 /* A bound template template parm could later be instantiated to have a valid
23801 nontype parm type via an alias template. */
23807 {
23810 else
23812 type);
23813 }
23815 }
23817 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23818 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23820 static bool
23822 {
23823 tree scope;
23825 /* [temp.dep.type]
23827 A type is dependent if it is:
23829 -- a template parameter. Template template parameters are types
23830 for us (since TYPE_P holds true for them) so we handle
23831 them here. */
23835 /* -- a qualified-id with a nested-name-specifier which contains a
23836 class-name that names a dependent type or whose unqualified-id
23837 names a dependent type. */
23841 /* An alias template specialization can be dependent even if the
23842 resulting type is not. */
23846 /* -- a cv-qualified type where the cv-unqualified type is
23847 dependent.
23848 No code is necessary for this bullet; the code below handles
23849 cv-qualified types, and we don't want to strip aliases with
23850 TYPE_MAIN_VARIANT because of DR 1558. */
23851 /* -- a compound type constructed from any dependent type. */
23861 {
23862 tree arg_type;
23867 arg_type;
23872 /* A value-dependent noexcept-specifier makes the type dependent. */
23875 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
23876 affect overload resolution and treating it as dependent breaks
23877 things. */
23882 }
23883 /* -- an array type constructed from any dependent type or whose
23884 size is specified by a constant expression that is
23885 value-dependent.
23887 We checked for type- and value-dependence of the bounds in
23888 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23890 {
23895 }
23897 /* -- a template-id in which either the template name is a template
23898 parameter ... */
23901 /* ... or any of the template arguments is a dependent type or
23902 an expression that is type-dependent or value-dependent. */
23904 && (any_dependent_template_arguments_p
23908 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23909 dependent; if the argument of the `typeof' expression is not
23910 type-dependent, then it should already been have resolved. */
23916 /* A template argument pack is dependent if any of its packed
23917 arguments are. */
23919 {
23925 }
23927 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23928 be template parameters. */
23935 /* The standard does not specifically mention types that are local
23936 to template functions or local classes, but they should be
23937 considered dependent too. For example:
23939 template <int I> void f() {
23940 enum E { a = I };
23941 S<sizeof (E)> s;
23942 }
23944 The size of `E' cannot be known until the value of `I' has been
23945 determined. Therefore, `E' must be considered dependent. */
23949 /* Don't use type_dependent_expression_p here, as it can lead
23950 to infinite recursion trying to determine whether a lambda
23951 nested in a lambda is dependent (c++/47687). */
23955 && (any_dependent_template_arguments_p
23959 /* Other types are non-dependent. */
23961 }
23963 /* Returns TRUE if TYPE is dependent, in the sense of
23964 [temp.dep.type]. Note that a NULL type is considered dependent. */
23966 bool
23968 {
23969 /* If there are no template parameters in scope, then there can't be
23970 any dependent types. */
23972 {
23973 /* If we are not processing a template, then nobody should be
23974 providing us with a dependent type. */
23978 }
23980 /* If the type is NULL, we have not computed a type for the entity
23981 in question; in that case, the type is dependent. */
23985 /* Erroneous types can be considered non-dependent. */
23989 /* Getting here with global_type_node means we improperly called this
23990 function on the TREE_TYPE of an IDENTIFIER_NODE. */
23993 /* If we have not already computed the appropriate value for TYPE,
23994 do so now. */
23996 {
23999 }
24002 }
24004 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24005 lookup. In other words, a dependent type that is not the current
24006 instantiation. */
24008 bool
24010 {
24013 }
24015 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24016 an unknown base of 'this' (and is therefore instantiation-dependent). */
24018 static bool
24020 {
24037 }
24039 /* T is a SCOPE_REF; return whether we need to consider it
24040 instantiation-dependent so that we can check access at instantiation
24041 time even though we know which member it resolves to. */
24043 static bool
24045 {
24052 else
24054 }
24056 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24057 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24058 expression. */
24060 /* Note that this predicate is not appropriate for general expressions;
24061 only constant expressions (that satisfy potential_constant_expression)
24062 can be tested for value dependence. */
24064 bool
24066 {
24070 /* A type-dependent expression is also value-dependent. */
24075 {
24077 /* A dependent member function of the current instantiation. */
24081 /* A dependent member function of the current instantiation. */
24088 /* A name that has not been looked up -- must be dependent. */
24092 /* A non-type template parm. */
24096 /* A non-type template parm. */
24102 /* A constant with literal type and is initialized
24103 with an expression that is value-dependent. */
24105 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24109 {
24113 }
24122 /* These expressions are value-dependent if the type to which
24123 the cast occurs is dependent or the expression being casted
24124 is value-dependent. */
24125 {
24131 /* A functional cast has a list of operands. */
24134 {
24135 /* If there are no operands, it must be an expression such
24136 as "int()". This should not happen for aggregate types
24137 because it would form non-constant expressions. */
24142 }
24148 }
24153 /* FALLTHRU */
24156 /* A `sizeof' expression is value-dependent if the operand is
24157 type-dependent or is a pack expansion. */
24166 /* An 'encode' expression is value-dependent if the operand is
24167 type-dependent. */
24176 /* All instantiation-dependent expressions should also be considered
24177 value-dependent. */
24185 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24186 is value-dependent. */
24187 {
24196 }
24199 {
24216 }
24227 {
24231 }
24234 /* Treat all requires-expressions as value-dependent so
24235 we don't try to fold them. */
24242 {
24249 {
24251 /* In a call to a constexpr member function, look through the
24252 implicit ADDR_EXPR on the object argument so that it doesn't
24253 cause the call to be considered value-dependent. We also
24254 look through it in potential_constant_expression. */
24261 }
24263 }
24269 {
24271 tree val;
24278 }
24281 /* Treat a GNU statement expression as dependent to avoid crashing
24282 under instantiate_non_dependent_expr; it can't be constant. */
24286 /* A constant expression is value-dependent if any subexpression is
24287 value-dependent. */
24289 {
24296 {
24300 {
24303 /* In some cases, some of the operands may be missing.
24304 (For example, in the case of PREDECREMENT_EXPR, the
24305 amount to increment by may be missing.) That doesn't
24306 make the expression dependent. */
24309 }
24310 }
24314 }
24316 }
24318 /* The expression is not value-dependent. */
24320 }
24322 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24323 [temp.dep.expr]. Note that an expression with no type is
24324 considered dependent. Other parts of the compiler arrange for an
24325 expression with type-dependent subexpressions to have no type, so
24326 this function doesn't have to be fully recursive. */
24328 bool
24330 {
24339 /* An unresolved name is always dependent. */
24345 /* A fold expression is type-dependent. */
24352 /* Some expression forms are never type-dependent. */
24366 /* The types of these expressions depends only on the type to which
24367 the cast occurs. */
24376 /* The types of these expressions depends only on the type created
24377 by the expression. */
24380 {
24381 /* For NEW_EXPR tree nodes created inside a template, either
24382 the object type itself or a TREE_LIST may appear as the
24383 operand 1. */
24386 /* This is an array type. We need to check array dimensions
24387 as well. */
24389 || value_dependent_expression_p
24391 else
24393 }
24396 {
24400 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24401 contains an identifier associated by name lookup with one or more
24402 declarations declared with a dependent type, or...a
24403 nested-name-specifier or qualified-id that names a member of an
24404 unknown specialization. */
24407 }
24417 {
24418 tree elt;
24422 {
24425 }
24427 }
24429 /* A static data member of the current instantiation with incomplete
24430 array type is type-dependent, as the definition and specializations
24431 can have different bounds. */
24438 /* An array of unknown bound depending on a variadic parameter, eg:
24440 template<typename... Args>
24441 void foo (Args... args)
24442 {
24443 int arr[] = { args... };
24444 }
24446 template<int... vals>
24447 void bar ()
24448 {
24449 int arr[] = { vals... };
24450 }
24452 If the array has no length and has an initializer, it must be that
24453 we couldn't determine its length in cp_complete_array_type because
24454 it is dependent. */
24462 /* A function or variable template-id is type-dependent if it has any
24463 dependent template arguments. */
24467 {
24468 /* Consider the innermost template arguments, since those are the ones
24469 that come from the template-id; the template arguments for the
24470 enclosing class do not make it type-dependent unless they are used in
24471 the type of the decl. */
24473 && (any_dependent_template_arguments_p
24476 }
24478 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24479 type-dependent. Checking this is important for functions with auto return
24480 type, which looks like a dependent type. */
24488 {
24492 }
24494 /* Always dependent, on the number of arguments if nothing else. */
24499 {
24504 {
24510 }
24511 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24516 {
24521 }
24524 {
24531 }
24541 }
24545 /* Dependent type attributes might not have made it from the decl to
24546 the type yet. */
24552 }
24554 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24555 type-dependent if the expression refers to a member of the current
24556 instantiation and the type of the referenced member is dependent, or the
24557 class member access expression refers to a member of an unknown
24558 specialization.
24560 This function returns true if the OBJECT in such a class member access
24561 expression is of an unknown specialization. */
24563 bool
24565 {
24566 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24567 dependent. */
24572 }
24574 /* walk_tree callback function for instantiation_dependent_expression_p,
24575 below. Returns non-zero if a dependent subexpression is found. */
24577 static tree
24580 {
24582 {
24583 /* We don't have to worry about decltype currently because decltype
24584 of an instantiation-dependent expr is a dependent type. This
24585 might change depending on the resolution of DR 1172. */
24588 }
24591 {
24592 /* Don't treat an argument list as dependent just because it has no
24593 TREE_TYPE. */
24601 /* Handle expressions with type operands. */
24606 {
24611 {
24614 else
24615 {
24618 }
24619 }
24621 }
24625 /* In a template, finish_class_member_access_expr creates a
24626 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24627 type-dependent, so that we can check access control at
24628 instantiation time (PR 42277). See also Core issue 1273. */
24635 else
24638 /* Treat statement-expressions as dependent. */
24642 /* Treat requires-expressions as dependent. */
24647 /* Treat calls to function concepts as dependent. */
24653 /* And variable concepts. */
24660 }
24664 else
24666 }
24668 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24669 sense defined by the ABI:
24671 "An expression is instantiation-dependent if it is type-dependent
24672 or value-dependent, or it has a subexpression that is type-dependent
24673 or value-dependent."
24675 Except don't actually check value-dependence for unevaluated expressions,
24676 because in sizeof(i) we don't care about the value of i. Checking
24677 type-dependence will in turn check value-dependence of array bounds/template
24678 arguments as needed. */
24680 bool
24682 {
24683 tree result;
24694 }
24696 /* As above, but also check value-dependence of the expression as a whole. */
24698 bool
24700 {
24703 }
24705 /* Like type_dependent_expression_p, but it also works while not processing
24706 a template definition, i.e. during substitution or mangling. */
24708 bool
24710 {
24716 }
24718 /* Returns TRUE if ARGS contains a type-dependent expression. */
24720 bool
24722 {
24724 tree arg;
24727 {
24730 }
24732 }
24734 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24735 expressions) contains any type-dependent expressions. */
24737 bool
24739 {
24745 }
24747 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24748 expressions) contains any value-dependent expressions. */
24750 bool
24752 {
24758 }
24760 /* Returns TRUE if the ARG (a template argument) is dependent. */
24762 bool
24764 {
24768 /* Assume a template argument that was wrongly written by the user
24769 is dependent. This is consistent with what
24770 any_dependent_template_arguments_p [that calls this function]
24771 does. */
24781 {
24784 /* A member template of a dependent class is not necessarily
24785 type-dependent, but it is a dependent template argument because it
24786 will be a member of an unknown specialization to that template. */
24789 }
24791 {
24795 {
24798 }
24801 }
24804 else
24807 }
24809 /* Returns true if ARGS (a collection of template arguments) contains
24810 any types that require structural equality testing. */
24812 bool
24814 {
24824 {
24827 {
24833 {
24834 /* Look inside the argument pack. */
24837 }
24840 {
24853 }
24854 }
24855 }
24858 }
24860 /* Returns true if ARGS (a collection of template arguments) contains
24861 any dependent arguments. */
24863 bool
24865 {
24875 {
24880 }
24883 }
24885 /* Returns TRUE if the template TMPL is type-dependent. */
24887 bool
24889 {
24891 {
24896 }
24898 /* Template template parameters are dependent. */
24902 /* So are names that have not been looked up. */
24906 }
24908 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24910 bool
24912 {
24915 }
24917 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24918 are dependent. */
24920 bool
24922 {
24929 {
24951 {
24955 }
24959 {
24963 {
24968 }
24969 }
24970 }
24973 }
24975 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24976 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24977 no such TYPE can be found. Note that this function peers inside
24978 uninstantiated templates and therefore should be used only in
24979 extremely limited situations. ONLY_CURRENT_P restricts this
24980 peering to the currently open classes hierarchy (which is required
24981 when comparing types). */
24983 tree
24985 {
24986 tree scope;
24987 tree name;
24988 tree decl;
24990 tree pushed_scope;
24991 tree result;
24996 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24997 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24998 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24999 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25000 identifier of the TYPENAME_TYPE anymore.
25001 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25002 TYPENAME_TYPE instead, we avoid messing up with a possible
25003 typedef variant case. */
25006 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25007 it first before we can figure out what NAME refers to. */
25009 {
25011 /* Given a class template A with a dependent base with nested type C,
25012 typedef typename A::C::C C will land us here, as trying to resolve
25013 the initial A::C leads to the local C typedef, which leads back to
25014 A::C::C. So we break the recursion now. */
25016 else
25018 }
25019 /* If we don't know what SCOPE refers to, then we cannot resolve the
25020 TYPENAME_TYPE. */
25023 /* If this is a typedef, we don't want to look inside (c++/11987). */
25026 /* If SCOPE isn't the template itself, it will not have a valid
25027 TYPE_FIELDS list. */
25029 /* scope is either the template itself or a compatible instantiation
25030 like X<T>, so look up the name in the original template. */
25032 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25034 /* If scope has no fields, it can't be a current instantiation. Check this
25035 before currently_open_class to avoid infinite recursion (71515). */
25038 /* If the SCOPE is not the current instantiation, there's no reason
25039 to look inside it. */
25042 /* Enter the SCOPE so that name lookup will be resolved as if we
25043 were in the class definition. In particular, SCOPE will no
25044 longer be considered a dependent type. */
25046 /* Look up the declaration. */
25048 tf_warning_or_error);
25052 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25053 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25059 {
25063 }
25066 {
25067 /* Obtain the template and the arguments. */
25070 {
25071 /* We get here with a plain identifier because a previous tentative
25072 parse of the nested-name-specifier as part of a ptr-operator saw
25073 ::template X<A>. The use of ::template is necessary in a
25074 ptr-operator, but wrong in a declarator-id.
25076 [temp.names]: In a qualified-id of a declarator-id, the keyword
25077 template shall not appear at the top level. */
25081 }
25083 /* Instantiate the template. */
25089 }
25091 /* Leave the SCOPE. */
25095 /* If we failed to resolve it, return the original typename. */
25099 /* If lookup found a typename type, resolve that too. */
25101 {
25102 /* Ill-formed programs can cause infinite recursion here, so we
25103 must catch that. */
25107 }
25109 /* Qualify the resulting type. */
25115 }
25117 /* EXPR is an expression which is not type-dependent. Return a proxy
25118 for EXPR that can be used to compute the types of larger
25119 expressions containing EXPR. */
25121 tree
25123 {
25125 tree inner_expr;
25127 /* When checking, try to get a constant value for all non-dependent
25128 expressions in order to expose bugs in *_dependent_expression_p
25129 and constexpr. This can affect code generation, see PR70704, so
25130 only do this for -fchecking=2. */
25133 /* Don't do this during nsdmi parsing as it can lead to
25134 unexpected recursive instantiations. */
25136 /* Don't do this during concept expansion either and for
25137 the same reason. */
25143 /* Preserve OVERLOADs; the functions must be available to resolve
25144 types. */
25155 /* There is no need to return a proxy for a variable. */
25158 /* Preserve string constants; conversions from string constants to
25159 "char *" are allowed, even though normally a "const char *"
25160 cannot be used to initialize a "char *". */
25163 /* Preserve void and arithmetic constants, as an optimization -- there is no
25164 reason to create a new node. */
25169 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25170 There is at least one place where we want to know that a
25171 particular expression is a throw-expression: when checking a ?:
25172 expression, there are special rules if the second or third
25173 argument is a throw-expression. */
25177 /* Don't wrap an initializer list, we need to be able to look inside. */
25181 /* Don't wrap a dummy object, we need to be able to test for it. */
25200 /* If the type is unknown, it can't really be non-dependent */
25203 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25205 }
25207 /* ARGS is a vector of expressions as arguments to a function call.
25208 Replace the arguments with equivalent non-dependent expressions.
25209 This modifies ARGS in place. */
25211 void
25213 {
25215 tree arg;
25218 {
25222 }
25223 }
25225 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25226 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25227 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25229 static tree
25231 {
25245 }
25247 tree
25249 {
25251 }
25253 tree
25255 {
25257 }
25259 /* Return a C++17 deduction placeholder for class template TMPL. */
25261 tree
25263 {
25267 }
25269 /* True iff T is a C++17 class template deduction placeholder. */
25271 bool
25273 {
25275 }
25277 /* Make a "constrained auto" type-specifier. This is an
25278 auto type with constraints that must be associated after
25279 deduction. The constraint is formed from the given
25280 CONC and its optional sequence of arguments, which are
25281 non-null if written as partial-concept-id. */
25283 tree
25285 {
25288 /* Build the constraint. */
25296 /* Our canonical type depends on the constraint. */
25299 /* Attach the constraint to the type declaration. */
25302 }
25304 /* Given type ARG, return std::initializer_list<ARG>. */
25306 static tree
25308 {
25312 {
25316 "deducing from brace-enclosed initializer list"
25320 }
25326 }
25328 /* Replace auto in TYPE with std::initializer_list<auto>. */
25330 static tree
25332 {
25339 }
25341 /* Hash traits for hashing possibly constrained 'auto'
25342 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25345 {
25348 };
25350 /* Hash the 'auto' T. */
25352 inline hashval_t
25354 {
25356 /* Matching constrained-type-specifiers denote the same template
25357 parameter, so hash the constraint. */
25359 else
25360 /* But unconstrained autos are all separate, so just hash the pointer. */
25362 }
25364 /* Compare two 'auto's. */
25368 {
25375 /* Two unconstrained autos are distinct. */
25380 }
25382 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25383 constrained) auto, add it to the vector. */
25385 static int
25387 {
25390 {
25391 /* All the autos were built with index 0; fix that up now. */
25395 /* If this is a repeated constrained-type-specifier, use the index we
25396 chose before. */
25398 else
25399 {
25400 /* Otherwise this is new, so use the current count. */
25403 }
25405 }
25407 /* Always keep walking. */
25409 }
25411 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25412 says they can appear anywhere in the type. */
25414 static tree
25416 {
25425 {
25430 }
25433 }
25435 /* The stem for deduction guide names. */
25438 /* Return the name for a deduction guide for class template TMPL. */
25440 tree
25442 {
25453 }
25455 /* True if NAME is the name of a deduction guide. */
25457 bool
25459 {
25463 }
25465 /* True if FN is a deduction guide. */
25467 bool
25469 {
25474 }
25476 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25478 bool
25480 {
25487 }
25489 /* True if FN is a guide generated from a constructor template. */
25491 bool
25493 {
25501 }
25503 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25504 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25505 template parameter types. Note that the handling of template template
25506 parameters relies on current_template_parms being set appropriately for the
25507 new template. */
25509 static tree
25512 {
25515 tree newtype;
25518 {
25525 }
25526 else
25530 tree newdecl
25535 tree newidx;
25538 {
25548 {
25553 // First create a copy (ttargs) of tsubst_args with an
25554 // additional level for the template template parameter's own
25555 // template parameters (ttparms).
25556 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25564 // Substitute ttargs into ttparms to fix references to
25565 // other template parameters.
25567 complain);
25568 // Now substitute again with args based on tparms, to reduce
25569 // the level of the ttparms.
25572 complain);
25573 // Finally, tack the adjusted parms onto tparms.
25575 current_template_parms);
25577 }
25578 }
25579 else
25580 {
25582 tree newconst
25594 }
25597 }
25599 /* Returns a C++17 class deduction guide template based on the constructor
25600 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25601 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25603 static tree
25605 {
25609 location_t loc;
25613 {
25617 {
25620 }
25621 else
25631 }
25632 else
25633 {
25636 fn_tmpl
25646 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25647 fully specialized args for the enclosing class. Strip those off, as
25648 the deduction guide won't have those template parameters. */
25651 /* Discard the 'this' parameter. */
25659 {
25662 /* For a member template constructor, we need to flatten the two
25663 template parameter lists into one, and then adjust the function
25664 signature accordingly. This gets...complicated. */
25667 /* For a member template we should have two levels of parms/args, one
25668 for the class and one for the constructor. We stripped
25669 specialized args for further enclosing classes above. */
25673 /* Template args for translating references to the two-level template
25674 parameters into references to the one-level template parameters we
25675 are creating. */
25680 /* Template parms for the constructor template. */
25683 /* Template parms for the class template. */
25687 /* Template parms for the deduction guide start as a copy of the
25688 template parms for the class. We set current_template_parms for
25689 lookup_template_class_1. */
25695 /* Now we need to rewrite the constructor parms to append them to the
25696 class parms. */
25698 {
25713 }
25715 /* Now we have a final set of template parms to substitute into the
25716 function signature. */
25725 }
25727 }
25730 {
25731 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25735 }
25739 FUNCTION_DECL,
25756 }
25758 /* Deduce template arguments for the class template placeholder PTYPE for
25759 template TMPL based on the initializer INIT, and return the resulting
25760 type. */
25762 static tree
25764 tsubst_flags_t complain)
25765 {
25767 {
25768 /* We should have handled this in the caller. */
25774 }
25785 {
25788 {
25789 /* As an exception, the first phase in 16.3.1.7 (considering the
25790 initializer list as a single argument) is omitted if the
25791 initializer list consists of a single expression of type cv U,
25792 where U is a specialization of C or a class derived from a
25793 specialization of C. */
25804 }
25807 else
25809 }
25810 else
25821 /* Prune explicit deduction guides in copy-initialization context. */
25823 {
25829 {
25830 /* Found a nonconverting guide, prune the candidates. */
25837 }
25838 }
25843 {
25846 }
25849 // FIXME cache artificial deduction guides
25851 {
25856 else
25860 }
25864 /* If this is list-initialization and the class has a list constructor, first
25865 try deducing from the list as a single argument, as [over.match.list]. */
25869 {
25873 }
25875 {
25881 {
25882 /* That didn't work, now try treating the list as a sequence of
25883 arguments. */
25886 }
25887 }
25889 /* Maybe generate an implicit deduction guide. */
25891 {
25895 /* Generate a copy guide. */
25898 /* Generate a default guide. */
25902 {
25905 }
25906 }
25909 {
25911 " of %qT, as it has no non-explicit deduction guides or "
25914 }
25916 {
25920 }
25923 {
25927 }
25930 {
25940 }
25945 }
25947 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25948 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25950 tree
25952 {
25954 tf_warning_or_error,
25955 adc_unspecified);
25956 }
25958 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25959 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25960 The CONTEXT determines the context in which auto deduction is performed
25961 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25962 OUTER_TARGS are used during template argument deduction
25963 (context == adc_unify) to properly substitute the result, and is ignored
25964 in other contexts.
25966 For partial-concept-ids, extra args may be appended to the list of deduced
25967 template arguments prior to determining constraint satisfaction. */
25969 tree
25973 {
25974 tree targs;
25981 /* Defining a subset of type-dependent expressions that we can deduce
25982 from ahead of time isn't worth the trouble. */
25985 /* Similarly, we can't deduce from another undeduced decl. */
25990 /* C++17 class template argument deduction. */
25994 /* Nothing we can do with this, even in deduction context. */
25997 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25998 with either a new invented type template parameter U or, if the
25999 initializer is a braced-init-list (8.5.4), with
26000 std::initializer_list<U>. */
26002 {
26007 else
26008 {
26010 {
26014 "for deduction to %<std::initializer_list%>, use copy-"
26016 }
26018 }
26019 }
26030 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26031 and initializer has array type, deduce cv-qualified array type. */
26033 complain);
26035 {
26044 {
26048 }
26049 }
26050 else
26051 {
26053 tree tparms;
26057 else
26058 {
26062 }
26069 {
26071 /* Try again at instantiation time. */
26075 /* If type is error_mark_node a diagnostic must have been
26076 emitted by now. Also, having a mention to '<type error>'
26077 in the diagnostic is not really useful to the user. */
26078 {
26082 else
26087 }
26089 }
26090 }
26092 /* Check any placeholder constraints against the deduced type. */
26095 {
26096 /* Use the deduced type to check the associated constraints. If we
26097 have a partial-concept-id, rebuild the argument list so that
26098 we check using the extra arguments. */
26102 {
26105 }
26106 else
26109 {
26111 {
26113 {
26131 }
26133 }
26135 }
26136 }
26142 }
26144 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26145 result. */
26147 tree
26149 {
26151 {
26157 /* In an abbreviated function template we didn't know we were dealing
26158 with a function template when we saw the auto return type, so update
26159 it to have the correct level. */
26161 }
26163 }
26165 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26166 'decltype(auto)' or a deduced class template. */
26168 bool
26170 {
26176 else
26178 }
26180 /* for_each_template_parm callback for type_uses_auto. */
26182 int
26184 {
26186 }
26188 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26189 a use of `auto'. Returns NULL_TREE otherwise. */
26191 tree
26193 {
26197 {
26198 /* The Concepts TS allows multiple autos in one type-specifier; just
26199 return the first one we find, do_auto_deduction will collect all of
26200 them. */
26204 else
26206 }
26207 else
26209 }
26211 /* For a given template T, return the vector of typedefs referenced
26212 in T for which access check is needed at T instantiation time.
26213 T is either a FUNCTION_DECL or a RECORD_TYPE.
26214 Those typedefs were added to T by the function
26215 append_type_to_template_for_access_check. */
26219 {
26220 tree ti;
26231 {
26236 }
26239 }
26241 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26242 tied to T. That list of typedefs will be access checked at
26243 T instantiation time.
26244 T is either a FUNCTION_DECL or a RECORD_TYPE.
26245 TYPE_DECL is a TYPE_DECL node representing a typedef.
26246 SCOPE is the scope through which TYPE_DECL is accessed.
26247 LOCATION is the location of the usage point of TYPE_DECL.
26249 This function is a subroutine of
26250 append_type_to_template_for_access_check. */
26252 static void
26254 tree type_decl,
26255 tree scope,
26256 location_t location)
26257 {
26258 qualified_typedef_usage_t typedef_usage;
26259 tree ti;
26266 && type_decl
26280 }
26282 /* Append TYPE_DECL to the template TEMPL.
26283 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26284 At TEMPL instanciation time, TYPE_DECL will be checked to see
26285 if it can be accessed through SCOPE.
26286 LOCATION is the location of the usage point of TYPE_DECL.
26288 e.g. consider the following code snippet:
26290 class C
26291 {
26292 typedef int myint;
26293 };
26295 template<class U> struct S
26296 {
26297 C::myint mi; // <-- usage point of the typedef C::myint
26298 };
26300 S<char> s;
26302 At S<char> instantiation time, we need to check the access of C::myint
26303 In other words, we need to check the access of the myint typedef through
26304 the C scope. For that purpose, this function will add the myint typedef
26305 and the scope C through which its being accessed to a list of typedefs
26306 tied to the template S. That list will be walked at template instantiation
26307 time and access check performed on each typedefs it contains.
26308 Note that this particular code snippet should yield an error because
26309 myint is private to C. */
26311 void
26313 tree type_decl,
26314 tree scope,
26315 location_t location)
26316 {
26322 /* Make sure we don't append the type to the template twice. */
26329 }
26331 /* Convert the generic type parameters in PARM that match the types given in the
26332 range [START_IDX, END_IDX) from the current_template_parms into generic type
26333 packs. */
26335 tree
26337 {
26348 {
26349 /* Create a distinct parameter pack type from the current parm and add it
26350 to the replacement args to tsubst below into the generic function
26351 parameter. */
26366 }
26372 /* If there are more levels then build up the replacement with the outer
26373 template parms. */
26377 replacement);
26380 }
26382 /* Entries in the decl_constraint hash table. */
26384 {
26385 tree decl;
26386 tree ci;
26387 };
26389 /* Hashing function and equality for constraint entries. */
26391 {
26393 {
26395 }
26398 {
26400 }
26401 };
26403 /* A mapping from declarations to constraint information. Note that
26404 both templates and their underlying declarations are mapped to the
26405 same constraint information.
26407 FIXME: This is defined in pt.c because garbage collection
26408 code is not being generated for constraint.cc. */
26412 /* Returns the template constraints of declaration T. If T is not
26413 constrained, return NULL_TREE. Note that T must be non-null. */
26415 tree
26417 {
26428 else
26430 }
26432 /* Associate the given constraint information CI with the declaration
26433 T. If T is a template, then the constraints are associated with
26434 its underlying declaration. Don't build associations if CI is
26435 NULL_TREE. */
26437 void
26439 {
26451 }
26453 /* Remove the associated constraints of the declaration T. */
26455 void
26457 {
26466 }
26468 /* Memoized satisfaction results for declarations. This
26469 maps the pair (constraint_info, arguments) to the result computed
26470 by constraints_satisfied_p. */
26473 {
26474 tree ci;
26475 tree args;
26476 tree result;
26477 };
26479 /* Hashing function and equality for constraint entries. */
26482 {
26484 {
26487 }
26490 {
26492 }
26493 };
26495 /* Memoized satisfaction results for concept checks. */
26498 {
26499 tree tmpl;
26500 tree args;
26501 tree result;
26502 };
26504 /* Hashing function and equality for constraint entries. */
26507 {
26509 {
26511 }
26514 {
26519 }
26520 };
26525 /* Search for a memoized satisfaction result. Returns one of the
26526 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26528 tree
26530 {
26535 else
26537 }
26539 /* Memoize the result of a satisfication test. Returns the saved result. */
26541 tree
26543 {
26550 }
26552 /* Search for a memoized satisfaction result for a concept. */
26554 tree
26556 {
26561 else
26563 }
26565 /* Memoize the result of a concept check. Returns the saved result. */
26567 tree
26569 {
26576 }
26580 /* Returns a prior concept specialization. This returns the substituted
26581 and normalized constraints defined by the concept. */
26583 tree
26585 {
26590 else
26592 }
26594 /* Save a concept expansion for later. */
26596 tree
26598 {
26605 }
26607 static hashval_t
26609 {
26618 }
26620 /* Compare the constraints of two subsumption entries. The LEFT1 and
26621 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26622 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26624 static bool
26626 {
26634 }
26636 /* Key/value pair for learning and memoizing subsumption results. This
26637 associates a pair of check constraints (including arguments) with
26638 a boolean value indicating the result. */
26641 {
26642 tree t1;
26643 tree t2;
26645 };
26647 /* Hashing function and equality for constraint entries. */
26650 {
26652 {
26654 }
26657 {
26662 }
26663 };
26667 /* Search for a previously cached subsumption result. */
26671 {
26676 else
26678 }
26680 /* Save a subsumption result. */
26682 bool
26684 {
26691 }
26693 /* Set up the hash table for constraint association. */
26695 void
26697 {
26706 }
26708 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26709 0..N-1. */
26711 void
26713 {
26716 integer_type_node,
26717 NULL_TREE),
26721 }
26723 /* Set up the hash tables for template instantiations. */
26725 void
26727 {
26733 }
26735 /* Print stats about the template hash tables for -fstats. */
26737 void
26739 {
26748 }
26750 #if CHECKING_P
26754 /* Verify that build_non_dependent_expr () works, for various expressions,
26755 and that location wrappers don't affect the results. */
26757 static void
26759 {
26762 /* Verify constants, without and with location wrappers. */
26779 }
26781 /* Verify that type_dependent_expression_p () works correctly, even
26782 in the presence of location wrapper nodes. */
26784 static void
26786 {
26791 /* If no templates are involved, nothing is type-dependent. */
26797 /* Within a template, an unresolved name is always type-dependent. */
26800 /* Ensure it copes with NULL_TREE and errors. */
26804 /* A USING_DECL in a template should be type-dependent, even if wrapped
26805 with a location wrapper (PR c++/83799). */
26814 }
26816 /* Run all of the selftests within this file. */
26818 void
26820 {
26823 }