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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. */
54 {
57 };
72 /* Live only within one (recursive) call to tsubst_expr. We use
73 this to pass the statement expression node from the STMT_EXPR
74 to the EXPR_STMT that is its result. */
77 // -------------------------------------------------------------------------- //
78 // Local Specialization Stack
79 //
80 // Implementation of the RAII helper for creating new local
81 // specializations.
84 {
87 else
89 }
92 {
95 }
97 /* True if we've recursed into fn_type_unification too many times. */
101 {
102 tree tmpl;
103 tree args;
104 tree spec;
105 };
108 {
111 };
117 /* Contains canonical template parameter types. The vector is indexed by
118 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
119 TREE_LIST, whose TREE_VALUEs contain the canonical template
120 parameters of various types and levels. */
123 #define UNIFY_ALLOW_NONE 0
124 #define UNIFY_ALLOW_MORE_CV_QUAL 1
125 #define UNIFY_ALLOW_LESS_CV_QUAL 2
126 #define UNIFY_ALLOW_DERIVED 4
127 #define UNIFY_ALLOW_INTEGER 8
128 #define UNIFY_ALLOW_OUTER_LEVEL 16
129 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
130 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
133 tbr_incomplete_type,
134 tbr_ambiguous_baseclass,
135 tbr_success
136 };
159 tree);
216 location_t);
228 /* Make the current scope suitable for access checking when we are
229 processing T. T can be FUNCTION_DECL for instantiated function
230 template, VAR_DECL for static member variable, or TYPE_DECL for
231 alias template (needed by instantiate_decl). */
233 static void
235 {
243 else
247 {
248 saved_access_scope = tree_cons
251 }
252 }
254 /* Restore the scope set up by push_access_scope. T is the node we
255 are processing. */
257 static void
259 {
261 {
264 }
268 else
270 }
272 /* Do any processing required when DECL (a member template
273 declaration) is finished. Returns the TEMPLATE_DECL corresponding
274 to DECL, unless it is a specialization, in which case the DECL
275 itself is returned. */
277 tree
279 {
286 {
287 tree type;
295 {
299 }
301 }
305 {
307 {
310 }
311 else
313 }
314 else
318 }
320 /* Create a template info node. */
322 tree
324 {
329 }
331 /* Return the template info node corresponding to T, whatever T is. */
333 tree
335 {
357 }
359 /* Returns the template nesting level of the indicated class TYPE.
361 For example, in:
362 template <class T>
363 struct A
364 {
365 template <class U>
366 struct B {};
367 };
369 A<T>::B<U> has depth two, while A<T> has depth one.
370 Both A<T>::B<int> and A<int>::B<U> have depth one, if
371 they are instantiations, not specializations.
373 This function is guaranteed to return 0 if passed NULL_TREE so
374 that, for example, `template_class_depth (current_class_type)' is
375 always safe. */
377 int
379 {
383 {
394 else
396 }
399 }
401 /* Subroutine of maybe_begin_member_template_processing.
402 Returns true if processing DECL needs us to push template parms. */
404 static bool
406 {
412 }
414 /* Subroutine of maybe_begin_member_template_processing.
415 Push the template parms in PARMS, starting from LEVELS steps into the
416 chain, and ending at the beginning, since template parms are listed
417 innermost first. */
419 static void
421 {
429 current_template_parms
435 NULL);
437 {
446 {
453 /* Push the CONST_DECL. */
459 }
460 }
461 }
463 /* Restore the template parameter context for a member template, a
464 friend template defined in a class definition, or a non-template
465 member of template class. */
467 void
469 {
470 tree parms;
475 {
478 /* Disregard full specializations (c++/60999). */
481 }
484 {
489 {
492 }
495 }
497 /* Remember how many levels of template parameters we pushed so that
498 we can pop them later. */
500 }
502 /* Undo the effects of maybe_begin_member_template_processing. */
504 void
506 {
515 {
519 }
520 }
522 /* Return a new template argument vector which contains all of ARGS,
523 but has as its innermost set of arguments the EXTRA_ARGS. */
525 static tree
527 {
528 tree new_args;
546 }
548 /* Like add_to_template_args, but only the outermost ARGS are added to
549 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
550 (EXTRA_ARGS) levels are added. This function is used to combine
551 the template arguments from a partial instantiation with the
552 template arguments used to attain the full instantiation from the
553 partial instantiation. */
555 static tree
557 {
558 tree new_args;
560 /* If there are more levels of EXTRA_ARGS than there are ARGS,
561 something very fishy is going on. */
564 /* If *all* the new arguments will be the EXTRA_ARGS, just return
565 them. */
569 /* For the moment, we make ARGS look like it contains fewer levels. */
574 /* Now, we restore ARGS to its full dimensions. */
578 }
580 /* Return the N levels of innermost template arguments from the ARGS. */
582 tree
584 {
585 tree new_args;
591 /* If N is 1, just return the innermost set of template arguments. */
595 /* If we're not removing anything, just return the arguments we were
596 given. */
602 /* Make a new set of arguments, not containing the outer arguments. */
609 }
611 /* The inverse of get_innermost_template_args: Return all but the innermost
612 EXTRA_LEVELS levels of template arguments from the ARGS. */
614 static tree
616 {
617 tree new_args;
623 /* If N is 1, just return the outermost set of template arguments. */
627 /* If we're not removing anything, just return the arguments we were
628 given. */
633 /* Make a new set of arguments, not containing the inner arguments. */
640 }
642 /* We've got a template header coming up; push to a new level for storing
643 the parms. */
645 void
647 {
648 /* We use a non-tag-transparent scope here, which causes pushtag to
649 put tags in this scope, rather than in the enclosing class or
650 namespace scope. This is the right thing, since we want
651 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
652 global template class, push_template_decl handles putting the
653 TEMPLATE_DECL into top-level scope. For a nested template class,
654 e.g.:
656 template <class T> struct S1 {
657 template <class T> struct S2 {};
658 };
660 pushtag contains special code to insert the TEMPLATE_DECL for S2
661 at the right scope. */
667 /* Add a dummy parameter level while we process the parameter list. */
668 current_template_parms
671 current_template_parms);
672 }
674 /* This routine is called when a specialization is declared. If it is
675 invalid to declare a specialization here, an error is reported and
676 false is returned, otherwise this routine will return true. */
678 static bool
680 {
683 /* [temp.expl.spec]
685 An explicit specialization shall be declared in the namespace of
686 which the template is a member, or, for member templates, in the
687 namespace of which the enclosing class or enclosing class
688 template is a member. An explicit specialization of a member
689 function, member class or static data member of a class template
690 shall be declared in the namespace of which the class template
691 is a member. */
693 {
696 }
698 /* [temp.expl.spec]
700 In an explicit specialization declaration for a member of a class
701 template or a member template that appears in namespace scope,
702 the member template and some of its enclosing class templates may
703 remain unspecialized, except that the declaration shall not
704 explicitly specialize a class member template if its enclosing
705 class templates are not explicitly specialized as well. */
707 {
710 }
713 }
715 /* We've just seen template <>. */
717 bool
719 {
723 }
725 /* Called at then end of processing a declaration preceded by
726 template<>. */
728 void
730 {
733 }
735 /* Any template <>'s that we have seen thus far are not referring to a
736 function specialization. */
738 void
740 {
743 }
745 /* We've just seen a template header. If SPECIALIZATION is nonzero,
746 it was of the form template <>. */
748 static void
750 {
752 template_header_count++;
753 }
755 /* We're beginning an explicit instantiation. */
757 void
759 {
762 }
765 void
767 {
770 }
772 /* An explicit specialization or partial specialization of TMPL is being
773 declared. Check that the namespace in which the specialization is
774 occurring is permissible. Returns false iff it is invalid to
775 specialize TMPL in the current namespace. */
777 static bool
779 {
782 /* [tmpl.expl.spec]
784 An explicit specialization shall be declared in a namespace enclosing the
785 specialized template. An explicit specialization whose declarator-id is
786 not qualified shall be declared in the nearest enclosing namespace of the
787 template, or, if the namespace is inline (7.3.1), any namespace from its
788 enclosing namespace set. */
791 {
794 }
797 /* Same or enclosing namespace. */
799 else
800 {
806 }
807 }
809 /* SPEC is an explicit instantiation. Check that it is valid to
810 perform this explicit instantiation in the current namespace. */
812 static void
814 {
815 tree ns;
817 /* DR 275: An explicit instantiation shall appear in an enclosing
818 namespace of its template. */
824 }
826 // Returns the type of a template specialization only if that
827 // specialization needs to be defined. Otherwise (e.g., if the type has
828 // already been defined), the function returns NULL_TREE.
829 static tree
831 {
832 // An implicit instantiation of an incomplete type implies
833 // the definition of a new class template.
834 //
835 // template<typename T>
836 // struct S;
837 //
838 // template<typename T>
839 // struct S<T*>;
840 //
841 // Here, S<T*> is an implicit instantiation of S whose type
842 // is incomplete.
846 // It can also be the case that TYPE is a completed specialization.
847 // Continuing the previous example, suppose we also declare:
848 //
849 // template<typename T>
850 // requires Integral<T>
851 // struct S<T*>;
852 //
853 // Here, S<T*> refers to the specialization S<T*> defined
854 // above. However, we need to differentiate definitions because
855 // we intend to define a new partial specialization. In this case,
856 // we rely on the fact that the constraints are different for
857 // this declaration than that above.
858 //
859 // Note that we also get here for injected class names and
860 // late-parsed template definitions. We must ensure that we
861 // do not create new type declarations for those cases.
863 {
867 // If there are no template parameters, this cannot be a new
868 // partial template specializtion?
872 // The injected-class-name is not a new partial specialization.
876 // If the constraints are not the same as those of the primary
877 // then, we can probably create a new specialization.
881 {
885 }
887 // Also, if there's a pre-existing specialization with matching
888 // constraints, then this also isn't new.
891 {
899 }
901 // Create a new type node (and corresponding type decl)
902 // for the newly declared specialization.
907 /* We only need a separate type node for storing the definition of this
908 partial specialization; uses of S<T*> are unconstrained, so all are
909 equivalent. So keep TYPE_CANONICAL the same. */
912 // Build the corresponding type decl.
918 }
921 }
923 /* The TYPE is being declared. If it is a template type, that means it
924 is a partial specialization. Do appropriate error-checking. */
926 tree
928 {
929 tree context;
934 /* A lambda that appears in specialization context is not itself a
935 specialization. */
940 {
944 }
949 {
955 else
958 }
960 {
961 /* This is for ordinary explicit specialization and partial
962 specialization of a template class such as:
964 template <> class C<int>;
966 or:
968 template <class T> class C<T*>;
970 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
973 {
980 {
985 }
986 }
992 /* Trying to define a specialization either without a template<> header
993 or in an inappropriate place. We've already given an error, so just
994 bail now so we don't actually define the specialization. */
996 }
1002 {
1003 /* This is for an explicit specialization of member class
1004 template according to [temp.expl.spec/18]:
1006 template <> template <class U> class C<int>::D;
1008 The context `C<int>' must be an implicit instantiation.
1009 Otherwise this is just a member class template declared
1010 earlier like:
1012 template <> class C<int> { template <class U> class D; };
1013 template <> template <class U> class C<int>::D;
1015 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1016 while in the second case, `C<int>::D' is a primary template
1017 and `C<T>::D' may not exist. */
1021 {
1022 tree t;
1027 {
1032 }
1034 /* Check for invalid specialization after instantiation:
1036 template <> template <> class C<int>::D<int>;
1037 template <> template <class U> class C<int>::D; */
1041 {
1045 {
1046 /* We already have a full specialization of this partial
1047 instantiation, or a full specialization has been
1048 looked up but not instantiated. Reassign it to the
1049 new member specialization template. */
1050 spec_entry elt;
1062 spec_entry **slot
1067 }
1068 else
1069 /* But if we've had an implicit instantiation, that's a
1070 problem ([temp.expl.spec]/6). */
1073 }
1075 /* Mark TYPE as a specialization. And as a result, we only
1076 have one level of template argument for the innermost
1077 class template. */
1082 }
1083 }
1085 {
1086 /* Someday C++0x may allow for enum template specialization. */
1091 else
1092 {
1095 }
1096 }
1099 }
1101 /* Returns nonzero if we can optimize the retrieval of specializations
1102 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1103 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1107 {
1110 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1111 parameter. */
1113 /* The optimized lookup depends on the fact that the
1114 template arguments for the member function template apply
1115 purely to the containing class, which is not true if the
1116 containing class is an explicit or partial
1117 specialization. */
1121 /* It is possible to have a template that is not a member
1122 template and is not a member of a template class:
1124 template <typename T>
1125 struct S { friend A::f(); };
1127 Here, the friend function is a template, but the context does
1128 not have template information. The optimized lookup relies
1129 on having ARGS be the template arguments for both the class
1130 and the function template. */
1132 }
1134 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1135 gone through coerce_template_parms by now. */
1137 static void
1139 {
1141 {
1150 /* Allow typedefs on the type of a non-type argument, since a
1152 else
1154 }
1155 }
1157 static void
1159 {
1164 }
1166 /* Retrieve the specialization (in the sense of [temp.spec] - a
1167 specialization is either an instantiation or an explicit
1168 specialization) of TMPL for the given template ARGS. If there is
1169 no such specialization, return NULL_TREE. The ARGS are a vector of
1170 arguments, or a vector of vectors of arguments, in the case of
1171 templates with more than one level of parameters.
1173 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1174 then we search for a partial specialization matching ARGS. This
1175 parameter is ignored if TMPL is not a class template.
1177 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1178 result is a NONTYPE_ARGUMENT_PACK. */
1180 static tree
1182 {
1192 /* There should be as many levels of arguments as there are
1193 levels of parameters. */
1202 /* Lambda functions in templates aren't instantiated normally, but through
1203 tsubst_lambda_expr. */
1208 {
1209 /* The template arguments actually apply to the containing
1210 class. Find the class specialization with those
1211 arguments. */
1213 tree class_specialization
1218 /* Find the instance of TMPL. */
1221 {
1224 /* using-declarations can add base methods to the method vec,
1225 and we don't want those here. */
1228 }
1230 }
1231 else
1232 {
1234 spec_entry elt;
1243 else
1251 }
1254 }
1256 /* Like retrieve_specialization, but for local declarations. */
1258 tree
1260 {
1266 }
1268 /* Returns nonzero iff DECL is a specialization of TMPL. */
1270 int
1272 {
1273 tree t;
1276 {
1282 }
1283 else
1284 {
1293 }
1296 }
1298 /* Returns nonzero iff DECL is a specialization of friend declaration
1299 FRIEND_DECL according to [temp.friend]. */
1301 bool
1303 {
1310 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1311 of a template class, we want to check if DECL is a specialization
1312 if this. */
1316 {
1317 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1320 }
1325 /* There is nothing to do if this is not a template friend. */
1332 /* [temp.friend/6]
1333 A member of a class template may be declared to be a friend of a
1334 non-template class. In this case, the corresponding member of
1335 every specialization of the class template is a friend of the
1336 class granting friendship.
1338 For example, given a template friend declaration
1340 template <class T> friend void A<T>::f();
1342 the member function below is considered a friend
1344 template <> struct A<int> {
1345 void f();
1346 };
1348 For this type of template friend, TEMPLATE_DEPTH below will be
1349 nonzero. To determine if DECL is a friend of FRIEND, we first
1350 check if the enclosing class is a specialization of another. */
1357 {
1358 /* Next, we check the members themselves. In order to handle
1359 a few tricky cases, such as when FRIEND_DECL's are
1361 template <class T> friend void A<T>::g(T t);
1362 template <class T> template <T t> friend void A<T>::h();
1364 and DECL's are
1366 void A<int>::g(int);
1367 template <int> void A<int>::h();
1369 we need to figure out ARGS, the template arguments from
1370 the context of DECL. This is required for template substitution
1371 of `T' in the function parameter of `g' and template parameter
1372 of `h' in the above examples. Here ARGS corresponds to `int'. */
1379 {
1381 {
1384 else
1386 current_depth++;
1387 }
1389 }
1392 {
1394 tree friend_type;
1395 tree decl_type;
1396 tree friend_args_type;
1397 tree decl_args_type;
1399 /* Make sure that both DECL and FRIEND_DECL are templates or
1400 non-templates. */
1406 {
1407 /* If both are templates, check template parameter list. */
1408 tree friend_parms
1413 friend_parms))
1417 }
1418 else
1426 /* Check if return types match. */
1430 /* Check if function parameter types match, ignoring the
1431 `this' parameter. */
1440 }
1441 else
1442 {
1443 /* DECL is a TYPE_DECL */
1447 /* Make sure that both DECL and FRIEND_DECL are templates or
1448 non-templates. */
1449 is_template
1456 {
1457 tree friend_parms;
1458 /* If both are templates, check the name of the two
1459 TEMPLATE_DECL's first because is_friend didn't. */
1464 /* Now check template parameter list. */
1465 friend_parms
1468 return comp_template_parms
1470 friend_parms);
1471 }
1472 else
1475 }
1476 }
1478 }
1480 /* Register the specialization SPEC as a specialization of TMPL with
1481 the indicated ARGS. IS_FRIEND indicates whether the specialization
1482 is actually just a friend declaration. ATTRLIST is the list of
1483 attributes that the specialization is declared with or NULL when
1484 it isn't. Returns SPEC, or an equivalent prior declaration, if
1485 available.
1487 We also store instantiations of field packs in the hash table, even
1488 though they are not themselves templates, to make lookup easier. */
1490 static tree
1492 hashval_t hash)
1493 {
1494 tree fn;
1496 spec_entry elt;
1504 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1505 register it; we want the corresponding TEMPLATE_DECL instead.
1506 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1507 the more obvious `uses_template_parms (spec)' to avoid problems
1508 with default function arguments. In particular, given
1509 something like this:
1511 template <class T> void f(T t1, T t = T())
1513 the default argument expression is not substituted for in an
1514 instantiation unless and until it is actually needed. */
1518 /* We don't put these specializations in the hash table, but we might
1519 want to give an error about a mismatch. */
1521 else
1522 {
1530 slot =
1534 else
1536 }
1538 /* We can sometimes try to re-register a specialization that we've
1539 already got. In particular, regenerate_decl_from_template calls
1540 duplicate_decls which will update the specialization list. But,
1541 we'll still get called again here anyhow. It's more convenient
1542 to simply allow this than to try to prevent it. */
1546 {
1548 {
1551 {
1553 fn);
1555 }
1556 else
1557 {
1558 tree clone;
1559 /* This situation should occur only if the first
1560 specialization is an implicit instantiation, the
1561 second is an explicit specialization, and the
1562 implicit instantiation has not yet been used. That
1563 situation can occur if we have implicitly
1564 instantiated a member function and then specialized
1565 it later.
1567 We can also wind up here if a friend declaration that
1568 looked like an instantiation turns out to be a
1569 specialization:
1571 template <class T> void foo(T);
1572 class S { friend void foo<>(int) };
1573 template <> void foo(int);
1575 We transform the existing DECL in place so that any
1576 pointers to it become pointers to the updated
1577 declaration.
1579 If there was a definition for the template, but not
1580 for the specialization, we want this to look as if
1581 there were no definition, and vice versa. */
1584 /* The call to duplicate_decls will have applied
1585 [temp.expl.spec]:
1587 An explicit specialization of a function template
1588 is inline only if it is explicitly declared to be,
1589 and independently of whether its function template
1590 is.
1592 to the primary function; now copy the inline bits to
1593 the various clones. */
1595 {
1602 }
1606 }
1607 }
1609 {
1612 /* We've already complained in duplicate_decls. */
1616 /* Dup decl failed, but this is a new definition. Set the
1617 line number so any errors match this new
1618 definition. */
1622 }
1623 }
1627 /* A specialization must be declared in the same namespace as the
1628 template it is specializing. */
1634 {
1643 /* If TMPL is a forward declaration of a template function, keep a list
1644 of all specializations in case we need to reassign them to a friend
1645 template later in tsubst_friend_function.
1647 Also keep a list of all variable template instantiations so that
1648 process_partial_specialization can check whether a later partial
1649 specialization would have used it. */
1652 }
1655 }
1657 /* Returns true iff two spec_entry nodes are equivalent. */
1661 bool
1663 {
1670 /* tmpl could be a FIELD_DECL for a capture pack. */
1674 {
1675 /* Partial specializations of a variable template can be distinguished by
1676 constraints. */
1680 }
1684 }
1686 /* Returns a hash for a template TMPL and template arguments ARGS. */
1688 static hashval_t
1690 {
1693 }
1695 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1696 ignoring SPEC. */
1698 hashval_t
1700 {
1702 }
1704 /* Recursively calculate a hash value for a template argument ARG, for use
1705 in the hash tables of template specializations. */
1707 hashval_t
1709 {
1729 {
1737 {
1742 }
1764 {
1768 {
1771 }
1773 }
1777 {
1780 }
1791 val = iterative_hash_template_arg
1803 val);
1805 val);
1814 /* A lambda can't appear in a template arg, but don't crash on
1815 erroneous input. */
1827 /* Now hash operands as usual. */
1832 }
1835 {
1838 {
1839 // We want an alias specialization that survived strip_typedefs
1840 // to hash differently from its TYPE_CANONICAL, to avoid hash
1841 // collisions that compare as different in template_args_equal.
1842 // These could be dependent specializations that strip_typedefs
1843 // left alone, or untouched specializations because
1844 // coerce_template_parms returns the unconverted template
1845 // arguments if it sees incomplete argument packs.
1848 }
1851 val);
1854 /* Otherwise just compare the types during lookup. */
1863 {
1868 }
1869 }
1872 }
1874 /* Unregister the specialization SPEC as a specialization of TMPL.
1875 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1876 if the SPEC was listed as a specialization of TMPL.
1878 Note that SPEC has been ggc_freed, so we can't look inside it. */
1880 bool
1882 {
1884 spec_entry elt;
1892 {
1897 }
1900 }
1902 /* Like register_specialization, but for local declarations. We are
1903 registering SPEC, an instantiation of TMPL. */
1905 void
1907 {
1910 }
1912 /* TYPE is a class type. Returns true if TYPE is an explicitly
1913 specialized class. */
1915 bool
1917 {
1921 }
1923 /* Print the list of functions at FNS, going through all the overloads
1924 for each element of the list. Alternatively, FNS can not be a
1925 TREE_LIST, in which case it will be printed together with all the
1926 overloads.
1928 MORE and *STR should respectively be FALSE and NULL when the function
1929 is called from the outside. They are used internally on recursive
1930 calls. print_candidates manages the two parameters and leaves NULL
1931 in *STR when it ends. */
1933 static void
1935 {
1939 else
1941 {
1947 {
1950 else
1953 }
1955 }
1956 }
1958 /* Print the list of candidate FNS in an error message. FNS can also
1959 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1961 void
1963 {
1967 }
1969 /* Get a (possibly) constrained template declaration for the
1970 purpose of ordering candidates. */
1971 static tree
1973 {
1979 }
1981 /* Among candidates having the same signature, return the
1982 most constrained or NULL_TREE if there is no best candidate.
1983 If the signatures of candidates vary (e.g., template
1984 specialization vs. member function), then there can be no
1985 most constrained.
1987 Note that we don't compare constraints on the functions
1988 themselves, but rather those of their templates. */
1989 static tree
1991 {
1992 // Try to find the best candidate in a first pass.
1995 {
2002 }
2004 // Verify that the champ is better than previous candidates.
2009 }
2012 }
2015 /* Returns the template (one of the functions given by TEMPLATE_ID)
2016 which can be specialized to match the indicated DECL with the
2017 explicit template args given in TEMPLATE_ID. The DECL may be
2018 NULL_TREE if none is available. In that case, the functions in
2019 TEMPLATE_ID are non-members.
2021 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2022 specialization of a member template.
2024 The TEMPLATE_COUNT is the number of references to qualifying
2025 template classes that appeared in the name of the function. See
2026 check_explicit_specialization for a more accurate description.
2028 TSK indicates what kind of template declaration (if any) is being
2029 declared. TSK_TEMPLATE indicates that the declaration given by
2030 DECL, though a FUNCTION_DECL, has template parameters, and is
2031 therefore a template function.
2033 The template args (those explicitly specified and those deduced)
2034 are output in a newly created vector *TARGS_OUT.
2036 If it is impossible to determine the result, an error message is
2037 issued. The error_mark_node is returned to indicate failure. */
2039 static tree
2041 tree decl,
2045 tmpl_spec_kind tsk)
2046 {
2047 tree fns;
2048 tree targs;
2049 tree explicit_targs;
2052 /* A TREE_LIST of templates of which DECL may be a specialization.
2053 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2054 corresponding TREE_PURPOSE is the set of template arguments that,
2055 when used to instantiate the template, would produce a function
2056 with the signature of DECL. */
2066 /* We shouldn't be specializing a member template of an
2067 unspecialized class template; we already gave an error in
2068 check_specialization_scope, now avoid crashing. */
2072 {
2075 }
2083 /* Check for baselinks. */
2088 {
2091 }
2093 {
2096 }
2098 /* Count the number of template headers specified for this
2099 specialization. */
2109 {
2112 tf_warning_or_error,
2116 }
2118 {
2122 {
2123 tree decl_arg_types;
2124 tree fn_arg_types;
2125 tree insttype;
2127 /* In case of explicit specialization, we need to check if
2128 the number of template headers appearing in the specialization
2129 is correct. This is usually done in check_explicit_specialization,
2130 but the check done there cannot be exhaustive when specializing
2131 member functions. Consider the following code:
2133 template <> void A<int>::f(int);
2134 template <> template <> void A<int>::f(int);
2136 Assuming that A<int> is not itself an explicit specialization
2137 already, the first line specializes "f" which is a non-template
2138 member function, whilst the second line specializes "f" which
2139 is a template member function. So both lines are syntactically
2140 correct, and check_explicit_specialization does not reject
2141 them.
2143 Here, we can do better, as we are matching the specialization
2144 against the declarations. We count the number of template
2145 headers, and we check if they match TEMPLATE_COUNT + 1
2146 (TEMPLATE_COUNT is the number of qualifying template classes,
2147 plus there must be another header for the member template
2148 itself).
2150 Notice that if header_count is zero, this is not a
2151 specialization but rather a template instantiation, so there
2152 is no check we can perform here. */
2156 /* Check that the number of template arguments at the
2157 innermost level for DECL is the same as for FN. */
2165 /* DECL might be a specialization of FN. */
2169 /* For a non-static member function, we need to make sure
2170 that the const qualification is the same. Since
2171 get_bindings does not try to merge the "this" parameter,
2172 we must do the comparison explicitly. */
2174 {
2179 /* And the ref-qualification. */
2183 }
2185 /* Skip the "this" parameter and, for constructors of
2186 classes with virtual bases, the VTT parameter. A
2187 full specialization of a constructor will have a VTT
2188 parameter, but a template never will. */
2189 decl_arg_types
2191 fn_arg_types
2194 /* Function templates cannot be specializations; there are
2195 no partial specializations of functions. Therefore, if
2196 the type of DECL does not match FN, there is no
2197 match.
2199 Note that it should never be the case that we have both
2200 candidates added here, and for regular member functions
2201 below. */
2203 {
2207 }
2209 /* See whether this function might be a specialization of this
2210 template. Suppress access control because we might be trying
2211 to make this specialization a friend, and we have already done
2212 access control for the declaration of the specialization. */
2218 /* We cannot deduce template arguments that when used to
2219 specialize TMPL will produce DECL. */
2223 /* We deduced something involving 'auto', which isn't a valid
2224 template argument. */
2227 /* Remove, from the set of candidates, all those functions
2228 whose constraints are not satisfied. */
2232 // Then, try to form the new function type.
2236 fn_arg_types
2241 /* Save this template, and the arguments deduced. */
2243 }
2245 /* FN is an ordinary member function, and we need a
2246 specialization of a member template. */
2247 ;
2249 /* We can get IDENTIFIER_NODEs here in certain erroneous
2250 cases. */
2251 ;
2253 /* This is just an ordinary non-member function. Nothing can
2254 be a specialization of that. */
2255 ;
2257 /* Cannot specialize functions that are created implicitly. */
2258 ;
2259 else
2260 {
2261 tree decl_arg_types;
2263 /* This is an ordinary member function. However, since
2264 we're here, we can assume its enclosing class is a
2265 template class. For example,
2267 template <typename T> struct S { void f(); };
2268 template <> void S<int>::f() {}
2270 Here, S<int>::f is a non-template, but S<int> is a
2271 template class. If FN has the same type as DECL, we
2272 might be in business. */
2275 /* Its enclosing class is an explicit specialization
2276 of a template class. This is not a candidate. */
2281 /* The return types differ. */
2284 /* Adjust the type of DECL in case FN is a static member. */
2291 decl_arg_types))
2299 // If the deduced arguments do not satisfy the constraints,
2300 // this is not a candidate.
2304 // Add the candidate.
2306 }
2307 }
2310 {
2311 /* We have:
2313 [temp.expl.spec]
2315 It is possible for a specialization with a given function
2316 signature to be instantiated from more than one function
2317 template. In such cases, explicit specification of the
2318 template arguments must be used to uniquely identify the
2319 function template specialization being specialized.
2321 Note that here, there's no suggestion that we're supposed to
2322 determine which of the candidate templates is most
2323 specialized. However, we, also have:
2325 [temp.func.order]
2327 Partial ordering of overloaded function template
2328 declarations is used in the following contexts to select
2329 the function template to which a function template
2330 specialization refers:
2332 -- when an explicit specialization refers to a function
2333 template.
2335 So, we do use the partial ordering rules, at least for now.
2336 This extension can only serve to make invalid programs valid,
2337 so it's safe. And, there is strong anecdotal evidence that
2338 the committee intended the partial ordering rules to apply;
2339 the EDG front end has that behavior, and John Spicer claims
2340 that the committee simply forgot to delete the wording in
2341 [temp.expl.spec]. */
2344 {
2347 }
2348 }
2350 // Concepts allows multiple declarations of member functions
2351 // with the same signature. Like above, we need to rely on
2352 // on the partial ordering of those candidates to determine which
2353 // is the best.
2355 {
2357 {
2360 }
2361 }
2364 {
2371 else
2374 }
2378 {
2384 }
2386 /* We have one, and exactly one, match. */
2388 {
2392 // Propagate the candidate's constraints to the declaration.
2395 /* DECL is a re-declaration or partial instantiation of a template
2396 function. */
2399 /* It was a specialization of an ordinary member function in a
2400 template class. */
2402 }
2404 /* It was a specialization of a template. */
2407 {
2412 }
2413 else
2416 }
2418 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2419 but with the default argument values filled in from those in the
2420 TMPL_TYPES. */
2422 static tree
2424 tree tmpl_types)
2425 {
2426 tree new_spec_types;
2434 /* Substitute into the rest of the list. */
2435 new_spec_types =
2439 /* Add the default argument for this parameter. */
2442 new_spec_types);
2443 }
2445 /* DECL is an explicit specialization. Replicate default arguments
2446 from the template it specializes. (That way, code like:
2448 template <class T> void f(T = 3);
2449 template <> void f(double);
2450 void g () { f (); }
2452 works, as required.) An alternative approach would be to look up
2453 the correct default arguments at the call-site, but this approach
2454 is consistent with how implicit instantiations are handled. */
2456 static void
2458 {
2459 tree tmpl;
2460 tree spec_types;
2461 tree tmpl_types;
2462 tree new_spec_types;
2463 tree old_type;
2464 tree new_type;
2465 tree t;
2470 /* See if there's anything we need to do. */
2483 {
2484 /* Remove the this pointer, but remember the object's type for
2485 CV quals. */
2491 {
2492 /* DECL may contain more parameters than TMPL due to the extra
2493 in-charge parameter in constructors and destructors. */
2496 }
2498 {
2501 }
2502 }
2504 /* Compute the merged default arguments. */
2505 new_spec_types =
2508 /* Compute the new FUNCTION_TYPE. */
2510 {
2514 new_spec_types);
2517 /* Put the in-charge parameter back. */
2520 new_spec_types);
2524 new_spec_types);
2525 }
2526 else
2528 new_spec_types);
2534 }
2536 /* Return the number of template headers we expect to see for a definition
2537 or specialization of CTYPE or one of its non-template members. */
2539 int
2541 {
2545 {
2546 /* You're supposed to have one `template <...>' for every
2547 template class, but you don't need one for a full
2548 specialization. For example:
2550 template <class T> struct S{};
2551 template <> struct S<int> { void f(); };
2552 void S<int>::f () {}
2554 is correct; there shouldn't be a `template <>' for the
2555 definition of `S<int>::f'. */
2557 /* If CTYPE does not have template information of any
2558 kind, then it is not a template, nor is it nested
2559 within a template. */
2567 }
2570 }
2572 /* Do a simple sanity check on the template headers that precede the
2573 variable declaration DECL. */
2575 void
2577 {
2582 {
2585 "variable templates only available with "
2588 // Namespace-scope variable templates should have a template header.
2590 }
2592 {
2594 "too many template headers for %qD "
2600 "members of an explicitly specialized class are defined "
2602 }
2603 }
2605 /* An explicit specialization whose declarator-id or class-head-name is not
2606 qualified shall be declared in the nearest enclosing namespace of the
2607 template, or, if the namespace is inline (7.3.1), any namespace from its
2608 enclosing namespace set.
2610 If the name declared in the explicit instantiation is an unqualified name,
2611 the explicit instantiation shall appear in the namespace where its template
2612 is declared or, if that namespace is inline (7.3.1), any namespace from its
2613 enclosing namespace set. */
2615 void
2617 {
2622 {
2628 /* This was allowed in C++98, so only pedwarn. */
2630 "outside its namespace must use a nested-name-"
2632 }
2633 }
2635 /* Warn for a template specialization SPEC that is missing some of a set
2636 of function or type attributes that the template TEMPL is declared with.
2637 ATTRLIST is a list of additional attributes that SPEC should be taken
2638 to ultimately be declared with. */
2640 static void
2642 {
2649 /* Avoid warning if either declaration or its type is deprecated. */
2671 /* Avoid warning if the primary has no attributes. */
2675 /* Avoid warning if either declaration contains an attribute on
2676 the white list below. */
2679 };
2687 /* Avoid warning if the difference between the primary and
2688 the specialization is not in one of the attributes below. */
2692 };
2694 /* Put together a list of the black listed attributes that the primary
2695 template is declared with that the specialization is not, in case
2696 it's not apparent from the most recent declaration of the primary. */
2698 pretty_printer str;
2701 {
2703 {
2708 {
2718 }
2719 }
2720 }
2727 spec))
2733 }
2735 /* Check to see if the function just declared, as indicated in
2736 DECLARATOR, and in DECL, is a specialization of a function
2737 template. We may also discover that the declaration is an explicit
2738 instantiation at this point.
2740 Returns DECL, or an equivalent declaration that should be used
2741 instead if all goes well. Issues an error message if something is
2742 amiss. Returns error_mark_node if the error is not easily
2743 recoverable.
2745 FLAGS is a bitmask consisting of the following flags:
2747 2: The function has a definition.
2748 4: The function is a friend.
2750 The TEMPLATE_COUNT is the number of references to qualifying
2751 template classes that appeared in the name of the function. For
2752 example, in
2754 template <class T> struct S { void f(); };
2755 void S<int>::f();
2757 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2758 classes are not counted in the TEMPLATE_COUNT, so that in
2760 template <class T> struct S {};
2761 template <> struct S<int> { void f(); }
2762 template <> void S<int>::f();
2764 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2765 invalid; there should be no template <>.)
2767 If the function is a specialization, it is marked as such via
2768 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2769 is set up correctly, and it is added to the list of specializations
2770 for that template. */
2772 tree
2774 tree decl,
2777 tree attrlist)
2778 {
2787 tmpl_spec_kind tsk;
2790 {
2793 else
2795 }
2796 else
2800 {
2803 {
2806 }
2808 {
2810 /* This could be something like:
2812 template <class T> void f(T);
2813 class S { friend void f<>(int); } */
2815 else
2816 {
2817 /* This case handles bogus declarations like template <>
2818 template <class T> void f<int>(); */
2821 declarator);
2823 }
2824 }
2828 /* The error has already been reported in
2829 check_specialization_scope. */
2835 /* Fall through. */
2848 decl);
2851 else
2855 /* Fall through. */
2861 /* In cases like template<> constexpr bool v = true;
2862 We'll give an error in check_template_variable. */
2868 else
2874 {
2875 /* This case handles bogus declarations like template <>
2876 template <class T> void f<int>(); */
2880 declarator);
2882 {
2883 /* Partial specialization of variable template. */
2887 }
2891 else
2895 ok:;
2896 }
2899 /* This is a specialization of a member template, without
2900 specialization the containing class. Something like:
2902 template <class T> struct S {
2903 template <class U> void f (U);
2904 };
2905 template <> template <class U> void S<int>::f(U) {}
2907 That's a specialization -- but of the entire template. */
2913 }
2916 /* This doesn't apply to variable templates. */
2919 {
2923 {
2927 }
2928 }
2931 {
2936 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2938 {
2939 tree fns;
2944 else
2945 {
2946 /* If there is no class context, the explicit instantiation
2947 must be at namespace scope. */
2950 /* Find the namespace binding, using the declaration
2951 context. */
2955 /* If lookup fails, look for a friend declaration so we can
2956 give a better diagnostic. */
2962 {
2965 }
2966 }
2969 }
2975 {
2977 /* A specialization in class scope. This is invalid,
2978 but the error will already have been flagged by
2979 check_specialization_scope. */
2981 else
2982 {
2983 /* It's not valid to write an explicit instantiation in
2984 class scope, e.g.:
2986 class C { template void f(); }
2988 This case is caught by the parser. However, on
2989 something like:
2991 template class C { void f(); };
2993 (which is invalid) we can get here. The error will be
2994 issued later. */
2995 ;
2996 }
2999 }
3002 {
3003 // We'll match variable templates in start_decl.
3007 /* Find the list of functions in ctype that have the same
3008 name as the declared function. */
3012 {
3016 {
3017 /* From [temp.expl.spec]:
3019 If such an explicit specialization for the member
3020 of a class template names an implicitly-declared
3021 special member function (clause _special_), the
3022 program is ill-formed.
3024 Similar language is found in [temp.explicit]. */
3027 }
3030 }
3032 /* For a type-conversion operator, We might be looking for
3033 `operator int' which will be a specialization of
3034 `operator T'. Grab all the conversion operators, and
3035 then select from them. */
3040 {
3043 }
3044 else
3046 }
3048 /* Figure out what exactly is being specialized at this point.
3049 Note that for an explicit instantiation, even one for a
3050 member function, we cannot tell a priori whether the
3051 instantiation is for a member template, or just a member
3052 function of a template class. Even if a member template is
3053 being instantiated, the member template arguments may be
3054 elided if they can be deduced from the rest of the
3055 declaration. */
3058 member_specialization,
3059 template_count,
3060 tsk);
3063 /* We couldn't figure out what this declaration was
3064 specializing. */
3066 else
3067 {
3070 {
3072 "friend declaration %qD is not visible to "
3076 }
3084 {
3085 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3086 is done by do_decl_instantiation later. */
3092 {
3093 /* If TMPL is not the most general template (for
3094 example, if TMPL is a friend template that is
3095 injected into namespace scope), then there will
3096 be too many levels of TARGS. Remove some of them
3097 here. */
3099 tree new_targs;
3106 }
3109 }
3111 /* If we thought that the DECL was a member function, but it
3112 turns out to be specializing a static member function,
3113 make DECL a static member function as well. */
3119 /* If this is a specialization of a member template of a
3120 template class, we want to return the TEMPLATE_DECL, not
3121 the specialization of it. */
3123 {
3128 {
3129 tree parm;
3133 /* We want to use the argument list specified in the
3134 definition, not in the original declaration. */
3139 }
3142 }
3144 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3150 /* Inherit default function arguments from the template
3151 DECL is specializing. */
3155 /* This specialization has the same protection as the
3156 template it specializes. */
3160 /* 7.1.1-1 [dcl.stc]
3162 A storage-class-specifier shall not be specified in an
3163 explicit specialization...
3165 The parser rejects these, so unless action is taken here,
3166 explicit function specializations will always appear with
3167 global linkage.
3169 The action recommended by the C++ CWG in response to C++
3170 defect report 605 is to make the storage class and linkage
3171 of the explicit specialization match the templated function:
3173 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3174 */
3176 {
3180 /* A concept cannot be specialized. */
3182 {
3184 gen_tmpl);
3186 }
3188 /* This specialization has the same linkage and visibility as
3189 the function template it specializes. */
3192 {
3195 }
3198 {
3201 }
3202 }
3204 /* If DECL is a friend declaration, declared using an
3205 unqualified name, the namespace associated with DECL may
3206 have been set incorrectly. For example, in:
3208 template <typename T> void f(T);
3209 namespace N {
3210 struct S { friend void f<int>(int); }
3211 }
3213 we will have set the DECL_CONTEXT for the friend
3214 declaration to N, rather than to the global namespace. */
3219 /* This is not really a declaration of a specialization.
3220 It's just the name of an instantiation. But, it's not
3221 a request for an instantiation, either. */
3224 /* A specialization is not necessarily COMDAT. */
3230 /* If this is a full specialization, register it so that we can find
3231 it again. Partial specializations will be registered in
3232 process_partial_specialization. */
3234 {
3239 }
3242 /* A 'structor should already have clones. */
3248 }
3249 }
3252 }
3254 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3255 parameters. These are represented in the same format used for
3256 DECL_TEMPLATE_PARMS. */
3258 int
3260 {
3261 const_tree p1;
3262 const_tree p2;
3270 {
3282 {
3286 /* If either of the template parameters are invalid, assume
3287 they match for the sake of error recovery. */
3300 }
3301 }
3304 /* One set of parameters has more parameters lists than the
3305 other. */
3309 }
3311 /* Determine whether PARM is a parameter pack. */
3313 bool
3315 {
3316 /* Determine if we have a non-type template parameter pack. */
3323 /* If this is a list of template parameters, we could get a
3324 TYPE_DECL or a TEMPLATE_DECL. */
3328 /* Otherwise it must be a type template parameter. */
3332 }
3334 /* Determine if T is a function parameter pack. */
3336 bool
3338 {
3342 }
3344 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3345 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3347 tree
3349 {
3356 }
3358 /* Return true iff the function parameter PARAM_DECL was expanded
3359 from the function parameter pack PACK. */
3361 bool
3363 {
3368 /* The parameter pack and its pack arguments have the same
3369 DECL_PARM_INDEX. */
3371 }
3373 /* Determine whether ARGS describes a variadic template args list,
3374 i.e., one that is terminated by a template argument pack. */
3376 static bool
3378 {
3380 tree last_parm;
3394 }
3396 /* Generate a new name for the parameter pack name NAME (an
3397 IDENTIFIER_NODE) that incorporates its */
3399 static tree
3401 {
3402 /* Munge the name to include the parameter index. */
3403 #define NUMBUF_LEN 128
3417 }
3419 /* Return true if T is a primary function, class or alias template
3420 specialization, not including the template pattern. */
3422 bool
3424 {
3440 }
3442 /* Return true if PARM is a template template parameter. */
3444 bool
3446 {
3448 }
3450 /* Return true iff PARM is a DECL representing a type template
3451 parameter. */
3453 bool
3455 {
3460 }
3462 /* Return the template parameters of T if T is a
3463 primary template instantiation, NULL otherwise. */
3465 tree
3467 {
3472 parms = INNERMOST_TEMPLATE_PARMS
3476 }
3478 /* Return the template parameters of the LEVELth level from the full list
3479 of template parameters PARMS. */
3481 tree
3483 {
3484 tree p;
3495 }
3497 /* Returns the template arguments of T if T is a template instantiation,
3498 NULL otherwise. */
3500 tree
3502 {
3510 }
3512 /* Return the argument pack elements of T if T is a template argument pack,
3513 NULL otherwise. */
3515 tree
3517 {
3523 }
3525 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3526 ARGUMENT_PACK_SELECT represents. */
3528 static tree
3530 {
3534 /* If the selected argument is an expansion E, that most likely means we were
3535 called from gen_elem_of_pack_expansion_instantiation during the
3536 substituting of an argument pack (of which the Ith element is a pack
3537 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3538 In this case, the Ith element resulting from this substituting is going to
3539 be a pack expansion, which pattern is the pattern of E. Let's return the
3540 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3541 resulting pack expansion from it. */
3543 {
3544 /* Make sure we aren't throwing away arg info. */
3547 }
3550 }
3553 /* True iff FN is a function representing a built-in variadic parameter
3554 pack. */
3556 bool
3558 {
3568 }
3570 /* True iff CALL is a call to a function representing a built-in variadic
3571 parameter pack. */
3573 static bool
3575 {
3579 }
3581 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3583 static tree
3585 tree in_decl)
3586 {
3592 {
3594 {
3597 }
3602 }
3603 else
3604 {
3608 /* Calculate the largest value of len that won't make the size of the vec
3609 overflow an int. The compiler will exceed resource limits long before
3610 this, but it seems a decent place to diagnose. */
3614 {
3619 }
3627 }
3628 }
3630 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3631 CALL. */
3633 static tree
3635 tree in_decl)
3636 {
3646 }
3648 /* Structure used to track the progress of find_parameter_packs_r. */
3649 struct find_parameter_pack_data
3650 {
3651 /* TREE_LIST that will contain all of the parameter packs found by
3652 the traversal. */
3655 /* Set of AST nodes that have been visited by the traversal. */
3658 /* True iff we're making a type pack expansion. */
3660 };
3662 /* Identifies all of the argument packs that occur in a template
3663 argument and appends them to the TREE_LIST inside DATA, which is a
3664 find_parameter_pack_data structure. This is a subroutine of
3665 make_pack_expansion and uses_parameter_packs. */
3666 static tree
3668 {
3674 /* Handle type aliases/typedefs. */
3676 {
3683 }
3685 /* Identify whether this is a parameter pack or not. */
3687 {
3695 /* FALLTHRU */
3697 /* If the placeholder appears in the decl-specifier-seq of a function
3698 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3699 is a pack expansion, the invented template parameter is a template
3700 parameter pack. */
3710 {
3711 /* We don't want to walk into the type of a PARM_DECL,
3712 because we don't want to see the type parameter pack. */
3715 }
3720 {
3721 /* We don't want to walk into the type of a variadic capture proxy,
3722 because we don't want to see the type parameter pack. */
3725 }
3727 {
3729 find_parameter_packs_r,
3732 }
3744 /* Not a parameter pack. */
3746 }
3749 {
3750 /* Add this parameter pack to the list. */
3752 }
3758 /* This switch statement will return immediately if we don't find a
3759 parameter pack. */
3761 {
3766 /* Check the template itself. */
3769 /* Check the template arguments. */
3783 /* Ignore the declaration of a capture proxy for a parameter pack. */
3791 /* Fall through. */
3836 {
3837 /* Look at explicit captures. */
3842 /* Since we defer implicit capture, look in the body as well. */
3848 }
3851 {
3852 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3853 type_pack_expansion_p to false so that any placeholders
3854 within the expression don't get marked as parameter packs. */
3862 }
3866 }
3869 }
3871 /* Determines if the expression or type T uses any parameter packs. */
3872 bool
3874 {
3883 }
3885 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3886 representation a base-class initializer into a parameter pack
3887 expansion. If all goes well, the resulting node will be an
3888 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3889 respectively. */
3890 tree
3892 {
3893 tree result;
3902 {
3903 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3904 class initializer. In this case, the TREE_PURPOSE will be a
3905 _TYPE node (representing the base class expansion we're
3906 initializing) and the TREE_VALUE will be a TREE_LIST
3907 containing the initialization arguments.
3909 The resulting expansion looks somewhat different from most
3910 expansions. Rather than returning just one _EXPANSION, we
3911 return a TREE_LIST whose TREE_PURPOSE is a
3912 TYPE_PACK_EXPANSION containing the bases that will be
3913 initialized. The TREE_VALUE will be identical to the
3914 original TREE_VALUE, which is a list of arguments that will
3915 be passed to each base. We do not introduce any new pack
3916 expansion nodes into the TREE_VALUE (although it is possible
3917 that some already exist), because the TREE_PURPOSE and
3918 TREE_VALUE all need to be expanded together with the same
3919 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3920 resulting TREE_PURPOSE will mention the parameter packs in
3921 both the bases and the arguments to the bases. */
3922 tree purpose;
3923 tree value;
3926 /* Determine which parameter packs will be used by the base
3927 class expansion. */
3936 {
3939 arg);
3942 }
3945 {
3946 /* Collect the sets of parameter packs used in each of the
3947 initialization arguments. */
3949 {
3950 /* Determine which parameter packs will be expanded in this
3951 argument. */
3954 }
3955 }
3959 /* Create the pack expansion type for the base type. */
3965 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3966 they will rarely be compared to anything. */
3970 }
3975 /* Build the PACK_EXPANSION_* node. */
3976 result = for_types
3981 {
3982 /* Propagate type and const-expression information. */
3985 /* Mark this read now, since the expansion might be length 0. */
3987 }
3988 else
3989 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3990 they will rarely be compared to anything. */
3993 /* Determine which parameter packs will be expanded. */
4000 /* Make sure we found some parameter packs. */
4002 {
4004 {
4007 else
4009 }
4011 }
4017 }
4019 /* Checks T for any "bare" parameter packs, which have not yet been
4020 expanded, and issues an error if any are found. This operation can
4021 only be done on full expressions or types (e.g., an expression
4022 statement, "if" condition, etc.), because we could have expressions like:
4024 foo(f(g(h(args)))...)
4026 where "args" is a parameter pack. check_for_bare_parameter_packs
4027 should not be called for the subexpressions args, h(args),
4028 g(h(args)), or f(g(h(args))), because we would produce erroneous
4029 error messages.
4031 Returns TRUE and emits an error if there were bare parameter packs,
4032 returns FALSE otherwise. */
4033 bool
4035 {
4042 /* A lambda might use a parameter pack from the containing context. */
4057 {
4061 {
4072 else
4077 else
4081 }
4084 }
4087 }
4089 /* Expand any parameter packs that occur in the template arguments in
4090 ARGS. */
4091 tree
4093 {
4102 /* First, determine if we need to expand anything, and the number of
4103 slots we'll need. */
4105 {
4110 {
4114 else
4116 }
4117 else
4118 {
4120 num_result_args++;
4121 }
4122 }
4124 /* If no expansion is necessary, we're done. */
4128 /* Expand arguments. */
4131 non_default_args_count =
4134 {
4137 {
4144 }
4145 else
4146 {
4149 }
4150 }
4154 }
4156 /* Checks if DECL shadows a template parameter.
4158 [temp.local]: A template-parameter shall not be redeclared within its
4159 scope (including nested scopes).
4161 Emits an error and returns TRUE if the DECL shadows a parameter,
4162 returns FALSE otherwise. */
4164 bool
4166 {
4167 tree olddecl;
4169 /* If we're not in a template, we can't possibly shadow a template
4170 parameter. */
4174 /* Figure out what we're shadowing. */
4178 /* If there's no previous binding for this name, we're not shadowing
4179 anything, let alone a template parameter. */
4183 /* If we're not shadowing a template parameter, we're done. Note
4184 that OLDDECL might be an OVERLOAD (or perhaps even an
4185 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4186 node. */
4190 /* We check for decl != olddecl to avoid bogus errors for using a
4191 name inside a class. We check TPFI to avoid duplicate errors for
4192 inline member templates. */
4198 /* Don't complain about the injected class name, as we've already
4199 complained about the class itself. */
4206 else
4211 }
4213 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4214 ORIG_LEVEL, DECL, and TYPE. */
4216 static tree
4220 tree decl,
4221 tree type)
4222 {
4233 }
4235 /* Find the canonical type parameter for the given template type
4236 parameter. Returns the canonical type parameter, which may be TYPE
4237 if no such parameter existed. */
4239 static tree
4241 {
4242 tree list;
4256 else
4257 {
4261 }
4262 }
4264 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4265 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4266 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4267 new one is created. */
4269 static tree
4271 tsubst_flags_t complain)
4272 {
4277 {
4296 /* Template template parameters need this. */
4298 {
4305 }
4306 }
4309 }
4311 /* Process information from new template parameter PARM and append it
4312 to the LIST being built. This new parameter is a non-type
4313 parameter iff IS_NON_TYPE is true. This new parameter is a
4314 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4315 is in PARM_LOC. */
4317 tree
4320 {
4329 {
4333 {
4337 else
4339 }
4342 }
4345 {
4351 {
4352 /* [temp.param]
4354 The top-level cv-qualifiers on the template-parameter are
4355 ignored when determining its type. */
4360 && !is_parameter_pack
4361 /* If we're in a nested template parameter list, the template
4362 template parameter could be a parameter pack. */
4364 {
4365 /* This template parameter is not a parameter pack, but it
4366 should be. Complain about "bare" parameter packs. */
4369 /* Recover by calling this a parameter pack. */
4371 }
4372 }
4374 /* A template parameter is not modifiable. */
4383 processing_template_decl,
4388 }
4389 else
4390 {
4391 tree t;
4395 {
4397 /* This is for distinguishing between real templates and template
4398 template parameters */
4402 }
4403 else
4404 {
4406 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4409 }
4416 processing_template_decl,
4420 }
4424 /* Build requirements for the type/template parameter.
4425 This must be done after SET_DECL_TEMPLATE_PARM_P or
4426 process_template_parm could fail. */
4434 /* Build the parameter node linking the parameter declaration,
4435 its default argument (if any), and its constraints (if any). */
4440 }
4442 /* The end of a template parameter list has been reached. Process the
4443 tree list into a parameter vector, converting each parameter into a more
4444 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4445 as PARM_DECLs. */
4447 tree
4449 {
4454 /* Pop the dummy parameter level and add the real one. */
4457 current_template_parms
4462 {
4466 }
4471 }
4473 // Explicitly indicate the end of the template parameter list. We assume
4474 // that the current template parameters have been constructed and/or
4475 // managed explicitly, as when creating new template template parameters
4476 // from a shorthand constraint.
4477 void
4479 {
4481 }
4483 /* end_template_decl is called after a template declaration is seen. */
4485 void
4487 {
4493 /* This matches the pushlevel in begin_template_parm_list. */
4498 }
4500 /* Takes a TREE_LIST representing a template parameter and convert it
4501 into an argument suitable to be passed to the type substitution
4502 functions. Note that If the TREE_LIST contains an error_mark
4503 node, the returned argument is error_mark_node. */
4505 tree
4507 {
4520 {
4524 {
4525 /* Turn this argument into a TYPE_ARGUMENT_PACK
4526 with a single element, which expands T. */
4535 }
4536 }
4537 else
4538 {
4542 {
4543 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4544 with a single element, which expands T. */
4554 }
4555 else
4557 }
4559 }
4561 /* Given a single level of template parameters (a TREE_VEC), return it
4562 as a set of template arguments. */
4564 static tree
4566 {
4576 }
4578 /* Given a set of template parameters, return them as a set of template
4579 arguments. The template parameters are represented as a TREE_VEC, in
4580 the form documented in cp-tree.h for template arguments. */
4582 static tree
4584 {
4585 tree header;
4590 /* If there is only one level of template parameters, we do not
4591 create a TREE_VEC of TREE_VECs. Instead, we return a single
4592 TREE_VEC containing the arguments. */
4597 {
4602 else
4604 }
4607 }
4609 /* Within the declaration of a template, return the currently active
4610 template parameters as an argument TREE_VEC. */
4612 static tree
4614 {
4616 }
4618 /* Update the declared TYPE by doing any lookups which were thought to be
4619 dependent, but are not now that we know the SCOPE of the declarator. */
4621 tree
4623 {
4634 /* Don't bother building up the args in this case. */
4636 {
4637 /* tsubst in the args corresponding to the template parameters,
4638 including auto if present. Most things will be unchanged, but
4639 make_typename_type and tsubst_qualified_id will resolve
4640 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4643 tree pushed;
4645 {
4649 }
4654 }
4660 {
4663 else
4665 }
4667 }
4669 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4670 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4671 the new template is a member template. */
4673 static tree
4675 {
4684 }
4686 struct template_parm_data
4687 {
4688 /* The level of the template parameters we are currently
4689 processing. */
4692 /* The index of the specialization argument we are currently
4693 processing. */
4696 /* An array whose size is the number of template parameters. The
4697 elements are nonzero if the parameter has been used in any one
4698 of the arguments processed so far. */
4701 /* An array whose size is the number of template arguments. The
4702 elements are nonzero if the argument makes use of template
4703 parameters of this level. */
4705 };
4707 /* Subroutine of push_template_decl used to see if each template
4708 parameter in a partial specialization is used in the explicit
4709 argument list. If T is of the LEVEL given in DATA (which is
4710 treated as a template_parm_data*), then DATA->PARMS is marked
4711 appropriately. */
4713 static int
4715 {
4723 {
4726 }
4728 /* In C++17 the type of a non-type argument is a deduced context. */
4733 data,
4734 NULL,
4737 /* Return zero so that for_each_template_parm will continue the
4738 traversal of the tree; we want to mark *every* template parm. */
4740 }
4742 /* Process the partial specialization DECL. */
4744 static tree
4746 {
4753 tree inner_parms;
4754 tree inst;
4764 /* A concept cannot be specialized. */
4766 {
4769 }
4774 /* We check that each of the template parameters given in the
4775 partial specialization is used in the argument list to the
4776 specialization. For example:
4778 template <class T> struct S;
4779 template <class T> struct S<T*>;
4781 The second declaration is OK because `T*' uses the template
4782 parameter T, whereas
4784 template <class T> struct S<int>;
4786 is no good. Even trickier is:
4788 template <class T>
4789 struct S1
4790 {
4791 template <class U>
4792 struct S2;
4793 template <class U>
4794 struct S2<T>;
4795 };
4797 The S2<T> declaration is actually invalid; it is a
4798 full-specialization. Of course,
4800 template <class U>
4801 struct S2<T (*)(U)>;
4803 or some such would have been OK. */
4811 {
4816 NULL,
4818 }
4821 {
4822 /* One of the template parms was not used in a deduced context in the
4823 specialization. */
4825 {
4829 }
4833 }
4838 /* [temp.class.spec]
4840 The argument list of the specialization shall not be identical to
4841 the implicit argument list of the primary template. */
4842 tree main_args
4845 && (!flag_concepts
4848 {
4851 "any template arguments; to define the primary template, "
4853 else
4855 "template arguments and is not more constrained than "
4856 "the primary template; to define the primary template, "
4859 }
4861 /* A partial specialization that replaces multiple parameters of the
4862 primary template with a pack expansion is less specialized for those
4863 parameters. */
4865 {
4867 "primary template because it replaces multiple parameters "
4870 /* Avoid crash in process_partial_specialization. */
4872 }
4874 /* If we aren't in a dependent class, we can actually try deduction. */
4876 /* FIXME we should be able to handle a partial specialization of a
4877 partial instantiation, but currently we can't (c++/41727). */
4880 {
4884 maintmpl);
4885 }
4887 /* [temp.class.spec]
4889 A partially specialized non-type argument expression shall not
4890 involve template parameters of the partial specialization except
4891 when the argument expression is a simple identifier.
4893 The type of a template parameter corresponding to a specialized
4894 non-type argument shall not be dependent on a parameter of the
4895 specialization.
4897 Also, we verify that pack expansions only occur at the
4898 end of the argument list. */
4902 {
4909 {
4910 /* Extract the arguments from the argument pack. We'll be
4911 iterating over these in the following loop. */
4914 }
4917 {
4919 /* Get the Jth argument in the parameter pack. */
4923 {
4924 /* Pack expansions must come at the end of the
4925 argument list. */
4928 {
4932 else
4935 }
4936 }
4939 /* We only care about the pattern. */
4945 /* This next two lines are the `argument expression is not just a
4946 simple identifier' condition and also the `specialized
4947 non-type argument' bit. */
4951 {
4955 arg);
4956 else
4957 {
4958 /* Look at the corresponding template parameter,
4959 marking which template parameters its type depends
4960 upon. */
4964 {
4965 /* We haven't yet initialized TPD2. Do so now. */
4967 /* The number of parameters here is the number in the
4968 main template, which, as checked in the assertion
4969 above, is NARGS. */
4973 }
4975 /* Mark the template parameters. But this time, we're
4976 looking for the template parameters of the main
4977 template, not in the specialization. */
4984 NULL,
4988 {
4989 /* The type depended on some template parameters.
4990 If they are fully specialized in the
4991 specialization, that's OK. */
5000 "type %qT of template argument %qE depends "
5002 "type %qT of template argument %qE depends "
5004 type,
5005 arg);
5006 }
5007 }
5008 }
5009 }
5010 }
5012 /* We should only get here once. */
5016 // Build the template decl.
5025 /* Give template template parms a DECL_CONTEXT of the template
5026 for which they are a parameter. */
5028 {
5032 }
5035 /* We didn't register this in check_explicit_specialization so we could
5036 wait until the constraints were set. */
5038 else
5048 {
5054 {
5062 "declaration of %qD ambiguates earlier template "
5066 "partial specialization of %qD after instantiation "
5068 }
5069 }
5072 }
5074 /* PARM is a template parameter of some form; return the corresponding
5075 TEMPLATE_PARM_INDEX. */
5077 static tree
5079 {
5092 }
5094 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5095 parameter packs used by the template parameter PARM. */
5097 static void
5099 {
5100 /* A type parm can't refer to another parm. */
5104 {
5108 }
5115 }
5117 /* PARM is a template parameter pack. Return any parameter packs used in
5118 its type or the type of any of its template parameters. If there are
5119 any such packs, it will be instantiated into a fixed template parameter
5120 list by partial instantiation rather than be fully deduced. */
5122 tree
5124 {
5125 /* This can only be true in a member template. */
5128 /* This can only be true for a parameter pack. */
5131 /* A type parm can't refer to another parm. */
5145 }
5147 /* Check that a template declaration's use of default arguments and
5148 parameter packs is not invalid. Here, PARMS are the template
5149 parameters. IS_PRIMARY is true if DECL is the thing declared by
5150 a primary template. IS_PARTIAL is true if DECL is a partial
5151 specialization.
5153 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5154 function template declaration or a friend class template
5155 declaration. In the function case, 1 indicates a declaration, 2
5156 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5157 emitted for extraneous default arguments.
5159 Returns TRUE if there were no errors found, FALSE otherwise. */
5161 bool
5164 {
5167 tree parm_level;
5170 /* [temp.param]
5172 A default template-argument shall not be specified in a
5173 function template declaration or a function template definition, nor
5174 in the template-parameter-list of the definition of a member of a
5175 class template. */
5179 /* You can't have a function template declaration in a local
5180 scope, nor you can you define a member of a class template in a
5181 local scope. */
5189 /* A lambda doesn't have an explicit declaration; don't complain
5190 about the parms of the enclosing class. */
5197 /* If this is either a friend defined in the scope of the class
5198 or a member function. */
5204 /* And, if it was a member function, it really was defined in
5205 the scope of the class. */
5208 /* We already checked these parameters when the template was
5209 declared, so there's no need to do it again now. This function
5210 was defined in class scope, but we're processing its body now
5211 that the class is complete. */
5214 /* Core issue 226 (C++0x only): the following only applies to class
5215 templates. */
5218 {
5219 /* [temp.param]
5221 If a template-parameter has a default template-argument, all
5222 subsequent template-parameters shall have a default
5223 template-argument supplied. */
5225 {
5232 {
5242 {
5244 /* For better subsequent error-recovery, we indicate that
5245 there should have been a default argument. */
5248 }
5250 && !is_friend_decl
5251 /* Don't complain about an enclosing partial
5252 specialization. */
5257 /* A fixed parameter pack will be partially
5258 instantiated into a fixed length list. */
5260 {
5261 /* A primary class template can only have one
5262 parameter pack, at the end of the template
5263 parameter list. */
5271 }
5272 }
5273 }
5274 }
5277 || is_partial
5278 || !is_primary
5280 /* For an ordinary class template, default template arguments are
5281 allowed at the innermost level, e.g.:
5282 template <class T = int>
5283 struct S {};
5284 but, in a partial specialization, they're not allowed even
5285 there, as we have in [temp.class.spec]:
5287 The template parameter list of a specialization shall not
5288 contain default template argument values.
5290 So, for a partial specialization, or for a function template
5291 (in C++98/C++03), we look at all of them. */
5292 ;
5293 else
5294 /* But, for a primary class template that is not a partial
5295 specialization we look at all template parameters except the
5296 innermost ones. */
5299 /* Figure out what error message to issue. */
5314 else
5315 /* Per [temp.param]/9, "A default template-argument shall not be
5316 specified in the template-parameter-lists of the definition of
5317 a member of a class template that appears outside of the member's
5318 class.", thus if we aren't handling a member of a class template
5319 there is no need to examine the parameters. */
5323 /* If we're inside a class definition, there's no need to
5324 examine the parameters to the class itself. On the one
5325 hand, they will be checked when the class is defined, and,
5326 on the other, default arguments are valid in things like:
5327 template <class T = double>
5328 struct S { template <class U> void f(U); };
5329 Here the default argument for `S' has no bearing on the
5330 declaration of `f'. */
5332 else
5333 /* Check everything. */
5339 {
5346 {
5351 {
5353 {
5360 }
5362 /* Clear out the default argument so that we are not
5363 confused later. */
5365 }
5366 }
5368 /* At this point, if we're still interested in issuing messages,
5369 they must apply to classes surrounding the object declared. */
5373 }
5376 }
5378 /* Worker for push_template_decl_real, called via
5379 for_each_template_parm. DATA is really an int, indicating the
5380 level of the parameters we are interested in. If T is a template
5381 parameter of that level, return nonzero. */
5383 static int
5385 {
5391 else
5394 }
5396 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5397 DATA is really an int, indicating the innermost outer level of parameters.
5398 If T is a template parameter of that level or further out, return
5399 nonzero. */
5401 static int
5403 {
5409 else
5412 }
5414 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5415 parameters given by current_template_args, or reuses a
5416 previously existing one, if appropriate. Returns the DECL, or an
5417 equivalent one, if it is replaced via a call to duplicate_decls.
5419 If IS_FRIEND is true, DECL is a friend declaration. */
5421 tree
5423 {
5424 tree tmpl;
5425 tree args;
5426 tree info;
5427 tree ctx;
5431 /* True if the template is a member template, in the sense of
5432 [temp.mem]. */
5438 /* See if this is a partial specialization. */
5451 /* For a friend, we want the context of the friend, not
5452 the type of which it is a friend. */
5456 /* In the case of a virtual function, we want the class in which
5457 it is defined. */
5459 else
5460 /* Otherwise, if we're currently defining some class, the DECL
5461 is assumed to be a member of the class. */
5470 /* See if this is a primary template. */
5473 /* A friend template that specifies a class context, i.e.
5474 template <typename T> friend void A<T>::f();
5475 is not primary. */
5480 else
5484 {
5491 {
5494 }
5496 {
5498 {
5501 }
5503 {
5504 /* [temp.mem]
5506 A destructor shall not be a member template. */
5509 }
5516 {
5517 /* [basic.stc.dynamic.allocation]
5519 An allocation function can be a function
5520 template. ... Template allocation functions shall
5521 have two or more parameters. */
5524 }
5525 }
5528 {
5529 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5532 {
5538 }
5539 }
5542 /* alias-declaration */
5546 else
5547 {
5550 }
5551 }
5553 /* Check to see that the rules regarding the use of default
5554 arguments are not being violated. We check args for a friend
5555 functions when we know whether it's a definition, introducing
5556 declaration or re-declaration. */
5561 /* Ensure that there are no parameter packs in the type of this
5562 declaration that have not been expanded. */
5564 {
5565 /* Check each of the arguments individually to see if there are
5566 any bare parameter packs. */
5572 {
5575 {
5576 /* This is a PARM_DECL that contains unexpanded parameter
5577 packs. We have already complained about this in the
5578 check_for_bare_parameter_packs call, so just replace
5579 these types with ERROR_MARK_NODE. */
5582 }
5586 }
5588 /* Check for bare parameter packs in the return type and the
5589 exception specifiers. */
5591 /* Errors were already issued, set return type to int
5592 as the frontend doesn't expect error_mark_node as
5593 the return type. */
5597 }
5602 {
5605 }
5618 {
5623 /* If DECL is a TYPE_DECL for a class-template, then there won't
5624 be DECL_LANG_SPECIFIC. The information equivalent to
5625 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5629 {
5630 /* Since a template declaration already existed for this
5631 class-type, we must be redeclaring it here. Make sure
5632 that the redeclaration is valid. */
5634 current_template_parms,
5636 /* We don't need to create a new TEMPLATE_DECL; just use the
5637 one we already had. */
5639 }
5640 else
5641 {
5643 member_template_p);
5648 {
5649 /* A specialization of a member template of a template
5650 class. */
5654 }
5655 }
5656 }
5657 else
5658 {
5664 {
5667 }
5675 {
5676 tree new_tmpl;
5678 /* The declaration is a specialization of a member
5679 template, declared outside the class. Therefore, the
5680 innermost template arguments will be NULL, so we
5681 replace them with the arguments determined by the
5682 earlier call to check_explicit_specialization. */
5685 new_tmpl
5687 member_template_p);
5697 args,
5700 }
5702 /* Make sure the template headers we got make sense. */
5707 {
5712 }
5713 else
5715 {
5720 {
5724 else
5728 /* Avoid crash in import_export_decl. */
5731 }
5736 /* Can happen in erroneous input. */
5738 else
5740 }
5742 /* Check that the parms are used in the appropriate qualifying scopes
5743 in the declarator. */
5747 {
5753 /* Avoid crash in import_export_decl. */
5756 }
5757 }
5762 /* Push template declarations for global functions and types. Note
5763 that we do not try to push a global template friend declared in a
5764 template class; such a thing may well depend on the template
5765 parameters of the class. */
5768 {
5773 /* Hide template friend classes that haven't been declared yet. */
5775 {
5778 }
5779 }
5782 {
5787 /* Give template template parms a DECL_CONTEXT of the template
5788 for which they are a parameter. */
5791 {
5795 }
5801 }
5803 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5804 back to its most general template. If TMPL is a specialization,
5805 ARGS may only have the innermost set of arguments. Add the missing
5806 argument levels if necessary. */
5814 else
5815 {
5820 }
5823 && !is_friend
5826 /* Set DECL_COMDAT on template instantiations; if we force
5827 them to be emitted by explicit instantiation or -frepo,
5828 mark_needed will tell cgraph to do the right thing. */
5832 }
5834 tree
5836 {
5838 }
5840 /* FN is an inheriting constructor that inherits from the constructor
5841 template INHERITED; turn FN into a constructor template with a matching
5842 template header. */
5844 tree
5846 {
5847 tree inner_parms
5850 tree parms
5861 }
5863 /* Called when a class template TYPE is redeclared with the indicated
5864 template PARMS, e.g.:
5866 template <class T> struct S;
5867 template <class T> struct S {}; */
5869 bool
5871 {
5872 tree tmpl;
5873 tree tmpl_parms;
5877 {
5880 }
5884 /* The type is nested in some template class. Nothing to worry
5885 about here; there are no new template parameters for the nested
5886 type. */
5890 {
5892 tmpl);
5894 }
5900 {
5910 }
5913 {
5914 tree tmpl_parm;
5915 tree parm;
5916 tree tmpl_default;
5917 tree parm_default;
5931 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5932 TEMPLATE_DECL. */
5942 {
5946 }
5949 {
5950 /* We have in [temp.param]:
5952 A template-parameter may not be given default arguments
5953 by two different declarations in the same scope. */
5958 }
5961 /* Update the previous template parameters (which are the ones
5962 that will really count) with the new default value. */
5965 /* Update the new parameters, too; they'll be used as the
5966 parameters for any members. */
5969 /* Give each template template parm in this redeclaration a
5970 DECL_CONTEXT of the template for which they are a parameter. */
5972 {
5975 }
5979 }
5981 // Cannot redeclare a class template with a different set of constraints.
5983 {
5988 }
5991 }
5993 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5994 to be used when the caller has already checked
5995 (processing_template_decl
5996 && !instantiation_dependent_expression_p (expr)
5997 && potential_constant_expression (expr))
5998 and cleared processing_template_decl. */
6000 tree
6002 {
6005 complain,
6009 }
6011 /* Simplify EXPR if it is a non-dependent expression. Returns the
6012 (possibly simplified) expression. */
6014 tree
6016 {
6020 /* If we're in a template, but EXPR isn't value dependent, simplify
6021 it. We're supposed to treat:
6023 template <typename T> void f(T[1 + 1]);
6024 template <typename T> void f(T[2]);
6026 as two declarations of the same function, for example. */
6029 {
6030 processing_template_decl_sentinel s;
6032 }
6034 }
6036 tree
6038 {
6040 }
6042 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6043 an uninstantiated expression. */
6045 tree
6047 {
6051 {
6054 else
6055 {
6056 processing_template_decl_sentinel s;
6058 }
6059 }
6061 }
6063 /* True iff T is a specialization of a variable template. */
6065 bool
6067 {
6072 }
6074 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6075 template declaration, or a TYPE_DECL for an alias declaration. */
6077 bool
6079 {
6087 }
6089 /* Return TRUE iff T is a specialization of an alias template. */
6091 bool
6093 {
6094 /* It's an alias template specialization if it's an alias and its
6095 TYPE_NAME is a specialization of a primary template. */
6101 }
6103 /* An alias template is complex from a SFINAE perspective if a template-id
6104 using that alias can be ill-formed when the expansion is not, as with
6105 the void_t template. We determine this by checking whether the
6106 expansion for the alias template uses all its template parameters. */
6108 struct uses_all_template_parms_data
6109 {
6112 };
6114 static int
6116 {
6124 }
6126 static bool
6128 {
6143 }
6145 /* Return TRUE iff T is a specialization of a complex alias template with
6146 dependent template-arguments. */
6148 bool
6150 {
6163 }
6165 /* Return the number of innermost template parameters in TMPL. */
6167 static int
6169 {
6172 }
6174 /* Return either TMPL or another template that it is equivalent to under DR
6175 1286: An alias that just changes the name of a template is equivalent to
6176 the other template. */
6178 static tree
6180 {
6183 {
6184 /* Determine if the alias is equivalent to an underlying template. */
6196 tree alias_args = INNERMOST_TEMPLATE_ARGS
6201 /* Alias is equivalent. Strip it and repeat. */
6203 }
6206 }
6208 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6209 must be a reference-to-function or a pointer-to-function type, as specified
6210 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6211 and check that the resulting function has external linkage. */
6213 static tree
6215 tsubst_flags_t complain)
6216 {
6219 linkage_kind linkage;
6234 /* [temp.arg.nontype]/1
6236 A template-argument for a non-type, non-template template-parameter
6237 shall be one of:
6238 [...]
6239 -- the address of an object or function with external [C++11: or
6240 internal] linkage. */
6243 {
6245 {
6251 else
6254 }
6256 }
6260 {
6262 {
6267 else
6271 }
6273 }
6275 accept:
6277 {
6280 else
6282 }
6287 }
6289 /* Subroutine of convert_nontype_argument.
6290 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6291 Emit an error otherwise. */
6293 static bool
6295 tsubst_flags_t complain)
6296 {
6313 {
6318 else
6320 }
6322 }
6324 /* Returns TRUE iff the address of OP is value-dependent.
6326 14.6.2.4 [temp.dep.temp]:
6327 A non-integral non-type template-argument is dependent if its type is
6328 dependent or it has either of the following forms
6329 qualified-id
6330 & qualified-id
6331 and contains a nested-name-specifier which specifies a class-name that
6332 names a dependent type.
6334 We generalize this to just say that the address of a member of a
6335 dependent class is value-dependent; the above doesn't cover the
6336 address of a static data member named with an unqualified-id. */
6338 static bool
6340 {
6341 /* We could use get_inner_reference here, but there's no need;
6342 this is only relevant for template non-type arguments, which
6343 can only be expressed as &id-expression. */
6345 {
6349 }
6352 }
6354 /* The next set of functions are used for providing helpful explanatory
6355 diagnostics for failed overload resolution. Their messages should be
6356 indented by two spaces for consistency with the messages in
6357 call.c */
6359 static int
6361 {
6363 }
6365 /* Other failure functions should call this one, to provide a single function
6366 for setting a breakpoint on. */
6368 static int
6370 {
6372 }
6374 static int
6376 {
6381 }
6383 static int
6385 {
6391 }
6393 static int
6395 {
6399 }
6401 static int
6403 {
6406 " template parameter %qD is not a parameter pack, but "
6410 }
6412 static int
6414 {
6417 " template argument %qE does not match "
6421 }
6423 static int
6425 {
6429 }
6431 static int
6433 {
6439 }
6441 static int
6443 {
6445 {
6450 else
6452 " deduced conflicting values for non-type parameter "
6454 }
6456 }
6458 static int
6460 {
6463 " variable-sized array type %qT is not "
6465 arg);
6467 }
6469 static int
6471 {
6475 arg);
6477 }
6479 static int
6481 {
6483 {
6489 else
6494 }
6496 }
6498 static int
6500 {
6502 }
6504 static int
6507 {
6509 }
6511 static int
6514 {
6520 }
6522 static int
6525 {
6528 {
6536 }
6538 }
6540 static int
6542 {
6545 " template parameters of a template template argument are "
6548 }
6550 static int
6552 {
6558 }
6560 static int
6562 {
6567 }
6569 /* Attempt to convert the non-type template parameter EXPR to the
6570 indicated TYPE. If the conversion is successful, return the
6571 converted value. If the conversion is unsuccessful, return
6572 NULL_TREE if we issued an error message, or error_mark_node if we
6573 did not. We issue error messages for out-and-out bad template
6574 parameters, but not simply because the conversion failed, since we
6575 might be just trying to do argument deduction. Both TYPE and EXPR
6576 must be non-dependent.
6578 The conversion follows the special rules described in
6579 [temp.arg.nontype], and it is much more strict than an implicit
6580 conversion.
6582 This function is called twice for each template argument (see
6583 lookup_template_class for a more accurate description of this
6584 problem). This means that we need to handle expressions which
6585 are not valid in a C++ source, but can be created from the
6586 first call (for instance, casts to perform conversions). These
6587 hacks can go away after we fix the double coercion problem. */
6589 static tree
6591 {
6592 tree expr_type;
6596 /* Detect immediately string literals as invalid non-type argument.
6597 This special-case is not needed for correctness (we would easily
6598 catch this later), but only to provide better diagnostic for this
6599 common user mistake. As suggested by DR 100, we do not mention
6600 linkage issues in the diagnostic as this is not the point. */
6601 /* FIXME we're making this OK. */
6603 {
6609 }
6611 /* Add the ADDR_EXPR now for the benefit of
6612 value_dependent_expression_p. */
6615 {
6619 }
6621 /* If we are in a template, EXPR may be non-dependent, but still
6622 have a syntactic, rather than semantic, form. For example, EXPR
6623 might be a SCOPE_REF, rather than the VAR_DECL to which the
6624 SCOPE_REF refers. Preserving the qualifying scope is necessary
6625 so that access checking can be performed when the template is
6626 instantiated -- but here we need the resolved form so that we can
6627 convert the argument. */
6639 /* If the argument is non-dependent, perform any conversions in
6640 non-dependent context as well. */
6648 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6649 to a non-type argument of "nullptr". */
6653 /* In C++11, integral or enumeration non-type template arguments can be
6654 arbitrary constant expressions. Pointer and pointer to
6655 member arguments can be general constant expressions that evaluate
6656 to a null value, but otherwise still need to be of a specific form. */
6658 {
6660 /* A PTRMEM_CST is already constant, and a valid template
6661 argument for a parameter of pointer to member type, we just want
6662 to leave it in that form rather than lower it to a
6666 {
6667 /* C++17: A template-argument for a non-type template-parameter shall
6668 be a converted constant expression (8.20) of the type of the
6669 template-parameter. */
6675 }
6677 {
6682 }
6683 }
6687 else
6690 /* HACK: Due to double coercion, we can get a
6691 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6692 which is the tree that we built on the first call (see
6693 below when coercing to reference to object or to reference to
6694 function). We just strip everything and get to the arg.
6695 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6696 for examples. */
6698 {
6704 {
6705 /* ??? Maybe we could use convert_from_reference here, but we
6706 would need to relax its constraints because the NOP_EXPR
6707 could actually change the type to something more cv-qualified,
6708 and this is not folded by convert_from_reference. */
6713 && (same_type_ignoring_top_level_qualifiers_p
6716 {
6719 }
6720 }
6721 }
6723 /* [temp.arg.nontype]/5, bullet 1
6725 For a non-type template-parameter of integral or enumeration type,
6726 integral promotions (_conv.prom_) and integral conversions
6727 (_conv.integral_) are applied. */
6729 {
6731 {
6736 }
6741 /* Notice that there are constant expressions like '4 % 0' which
6742 do not fold into integer constants. */
6745 {
6747 {
6751 else
6757 /* else cxx_constant_value complained but gave us
6758 a real constant, so go ahead. */
6760 {
6761 /* Some assemble time constant expressions like
6762 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6763 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6764 as we can emit them into .rodata initializers of
6765 variables, yet they can't fold into an INTEGER_CST at
6766 compile time. Refuse them here. */
6771 }
6772 }
6773 else
6775 }
6777 /* Avoid typedef problems. */
6780 }
6781 /* [temp.arg.nontype]/5, bullet 2
6783 For a non-type template-parameter of type pointer to object,
6784 qualification conversions (_conv.qual_) and the array-to-pointer
6785 conversion (_conv.array_) are applied. */
6787 {
6790 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6791 decay_conversion or an explicit cast. If it's a problematic cast,
6792 we'll complain about it below. */
6794 {
6799 {
6802 }
6803 }
6805 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6807 A template-argument for a non-type, non-template template-parameter
6808 shall be one of: [...]
6810 -- the name of a non-type template-parameter;
6811 -- the address of an object or function with external linkage, [...]
6812 expressed as "& id-expression" where the & is optional if the name
6813 refers to a function or array, or if the corresponding
6814 template-parameter is a reference.
6816 Here, we do not care about functions, as they are invalid anyway
6817 for a parameter of type pointer-to-object. */
6820 /* Non-type template parameters are OK. */
6821 ;
6825 {
6827 {
6830 "because %qD is a variable, not the address of "
6833 }
6835 {
6841 }
6842 /* Other values, like integer constants, might be valid
6843 non-type arguments of some other type. */
6845 }
6846 else
6847 {
6851 {
6856 }
6858 {
6864 }
6867 {
6872 }
6873 /* C++17: For a non-type template-parameter of reference or pointer
6874 type, the value of the constant expression shall not refer to (or
6875 for a pointer type, shall not be the address of):
6876 * a subobject (4.5),
6877 * a temporary object (15.2),
6878 * a string literal (5.13.5),
6879 * the result of a typeid expression (8.2.8), or
6880 * a predefined __func__ variable (11.4.1). */
6882 {
6885 decl);
6887 }
6891 {
6896 }
6898 {
6902 decl);
6904 }
6905 }
6912 }
6913 /* [temp.arg.nontype]/5, bullet 3
6915 For a non-type template-parameter of type reference to object, no
6916 conversions apply. The type referred to by the reference may be more
6917 cv-qualified than the (otherwise identical) type of the
6918 template-argument. The template-parameter is bound directly to the
6919 template-argument, which must be an lvalue. */
6921 {
6923 expr_type))
6927 {
6932 }
6935 {
6940 }
6942 /* [temp.arg.nontype]/1
6944 A template-argument for a non-type, non-template template-parameter
6945 shall be one of: [...]
6947 -- the address of an object or function with external linkage. */
6950 {
6953 {
6956 "because a reference variable does not have a constant "
6959 }
6960 }
6964 /* OK, dependent reference. We don't want to ask whether a DECL is
6966 else
6967 {
6969 {
6975 }
6977 /* DR 1155 allows internal linkage in C++11 and up. */
6980 {
6986 }
6989 }
6993 }
6994 /* [temp.arg.nontype]/5, bullet 4
6996 For a non-type template-parameter of type pointer to function, only
6997 the function-to-pointer conversion (_conv.func_) is applied. If the
6998 template-argument represents a set of overloaded functions (or a
6999 pointer to such), the matching function is selected from the set
7000 (_over.over_). */
7002 {
7003 /* If the argument is a template-id, we might not have enough
7004 context information to decay the pointer. */
7006 {
7010 }
7013 /* Null pointer values are OK in C++11. */
7019 }
7020 /* [temp.arg.nontype]/5, bullet 5
7022 For a non-type template-parameter of type reference to function, no
7023 conversions apply. If the template-argument represents a set of
7024 overloaded functions, the matching function is selected from the set
7025 (_over.over_). */
7027 {
7029 {
7031 {
7036 }
7038 }
7043 }
7044 /* [temp.arg.nontype]/5, bullet 6
7046 For a non-type template-parameter of type pointer to member function,
7047 no conversions apply. If the template-argument represents a set of
7048 overloaded member functions, the matching member function is selected
7049 from the set (_over.over_). */
7051 {
7056 /* [temp.arg.nontype] bullet 1 says the pointer to member
7057 expression must be a pointer-to-member constant. */
7062 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7063 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7066 }
7067 /* [temp.arg.nontype]/5, bullet 7
7069 For a non-type template-parameter of type pointer to data member,
7070 qualification conversions (_conv.qual_) are applied. */
7072 {
7073 /* [temp.arg.nontype] bullet 1 says the pointer to member
7074 expression must be a pointer-to-member constant. */
7082 }
7084 {
7086 {
7091 }
7093 }
7094 /* A template non-type parameter must be one of the above. */
7095 else
7098 /* Sanity check: did we actually convert the argument to the
7099 right type? */
7103 }
7105 /* Subroutine of coerce_template_template_parms, which returns 1 if
7106 PARM_PARM and ARG_PARM match using the rule for the template
7107 parameters of template template parameters. Both PARM and ARG are
7108 template parameters; the rest of the arguments are the same as for
7109 coerce_template_template_parms.
7110 */
7111 static int
7113 tree arg,
7114 tsubst_flags_t complain,
7115 tree in_decl,
7116 tree outer_args)
7117 {
7126 {
7128 /* We encounter instantiations of templates like
7129 template <template <template <class> class> class TT>
7130 class C; */
7131 {
7138 }
7139 /* Fall through. */
7144 /* Argument is a parameter pack but parameter is not. */
7149 /* The tsubst call is used to handle cases such as
7151 template <int> class C {};
7152 template <class T, template <T> class TT> class D {};
7153 D<int, C> d;
7155 i.e. the parameter list of TT depends on earlier parameters. */
7157 {
7162 }
7166 /* Argument is a parameter pack but parameter is not. */
7173 }
7176 }
7178 /* Coerce template argument list ARGLIST for use with template
7179 template-parameter TEMPL. */
7181 static tree
7183 tsubst_flags_t complain)
7184 {
7185 /* Consider an example where a template template parameter declared as
7187 template <class T, class U = std::allocator<T> > class TT
7189 The template parameter level of T and U are one level larger than
7190 of TT. To proper process the default argument of U, say when an
7191 instantiation `TT<int>' is seen, we need to build the full
7192 arguments containing {int} as the innermost level. Outer levels,
7193 available when not appearing as default template argument, can be
7194 obtained from the arguments of the enclosing template.
7196 Suppose that TT is later substituted with std::vector. The above
7197 instantiation is `TT<int, std::allocator<T> >' with TT at
7198 level 1, and T at level 2, while the template arguments at level 1
7199 becomes {std::vector} and the inner level 2 is {int}. */
7203 {
7205 /* We want arguments for the partial specialization, not arguments for
7206 the primary template. */
7208 else
7210 }
7212 {
7213 /* This is an argument of the current template, so we haven't set
7214 DECL_CONTEXT yet. */
7215 tree relevant_template_parms;
7217 /* Parameter levels that are greater than the level of the given
7218 template template parm are irrelevant. */
7225 }
7232 complain,
7235 }
7237 /* A cache of template template parameters with match-all default
7238 arguments. */
7240 static void
7242 {
7246 }
7247 static tree
7249 {
7254 }
7256 /* T is a bound template template-parameter. Copy its arguments into default
7257 arguments of the template template-parameter's template parameters. */
7259 static tree
7261 {
7284 {
7287 {
7290 }
7291 }
7295 }
7297 /* ARG is a bound potential template template-argument, and PARGS is a list
7298 of arguments for the corresponding template template-parameter. Adjust
7299 PARGS as appropriate for application to ARG's template, and if ARG is a
7300 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7301 arguments to the template template parameter. */
7303 static tree
7305 {
7309 {
7310 /* When comparing two template template-parameters in partial ordering,
7311 rewrite the one currently being used as an argument to have default
7312 arguments for all parameters. */
7318 }
7319 else
7320 {
7321 tree aparms
7326 }
7329 }
7331 /* Subroutine of unify for the case when PARM is a
7332 BOUND_TEMPLATE_TEMPLATE_PARM. */
7334 static int
7337 {
7341 /* The template template parm might be variadic and the argument
7342 not, so flatten both argument lists. */
7347 {
7348 /* In keeping with P0522R0, adjust P's template arguments
7349 to apply to A's template; then flatten it again. */
7358 /* If the P0522 adjustment eliminated a pack expansion, deduce
7359 empty packs. */
7365 }
7366 else
7367 {
7368 /* Deduce arguments T, i from TT<T> or TT<i>.
7369 We check each element of PARMVEC and ARGVEC individually
7370 rather than the whole TREE_VEC since they can have
7371 different number of elements, which is allowed under N2555. */
7375 /* Check if the parameters end in a pack, making them
7376 variadic. */
7383 /* If the template argument list of P contains a pack
7384 expansion that is not the last template argument, the
7385 entire template argument list is a non-deduced
7386 context. */
7404 DEDUCE_EXACT,
7407 }
7410 }
7412 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7413 template template parameters. Both PARM_PARMS and ARG_PARMS are
7414 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7415 or PARM_DECL.
7417 Consider the example:
7418 template <class T> class A;
7419 template<template <class U> class TT> class B;
7421 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7422 the parameters to A, and OUTER_ARGS contains A. */
7424 static int
7426 tree arg_parms,
7427 tsubst_flags_t complain,
7428 tree in_decl,
7429 tree outer_args)
7430 {
7442 {
7443 /* P0522R0: A template template-parameter P is at least as specialized as
7444 a template template-argument A if, given the following rewrite to two
7445 function templates, the function template corresponding to P is at
7446 least as specialized as the function template corresponding to A
7447 according to the partial ordering rules for function templates
7448 ([temp.func.order]). Given an invented class template X with the
7449 template parameter list of A (including default arguments):
7451 * Each of the two function templates has the same template parameters,
7452 respectively, as P or A.
7454 * Each function template has a single function parameter whose type is
7455 a specialization of X with template arguments corresponding to the
7456 template parameters from the respective function template where, for
7457 each template parameter PP in the template parameter list of the
7458 function template, a corresponding template argument AA is formed. If
7459 PP declares a parameter pack, then AA is the pack expansion
7460 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7462 If the rewrite produces an invalid type, then P is not at least as
7463 specialized as A. */
7465 /* So coerce P's args to apply to A's parms, and then deduce between A's
7466 args and the converted args. If that succeeds, A is at least as
7467 specialized as P, so they match.*/
7474 {
7480 }
7481 }
7483 /* Determine whether we have a parameter pack at the end of the
7484 template template parameter's template parameter list. */
7486 {
7493 {
7507 }
7508 }
7514 /* Check all of the template parameters except the parameter pack at
7515 the end (if any). */
7517 {
7526 outer_args))
7529 }
7532 {
7533 /* Check each of the template parameters in the template
7534 argument against the template parameter pack at the end of
7535 the template template parameter. */
7542 {
7549 outer_args))
7551 }
7552 }
7555 }
7557 /* Verifies that the deduced template arguments (in TARGS) for the
7558 template template parameters (in TPARMS) represent valid bindings,
7559 by comparing the template parameter list of each template argument
7560 to the template parameter list of its corresponding template
7561 template parameter, in accordance with DR150. This
7562 routine can only be called after all template arguments have been
7563 deduced. It will return TRUE if all of the template template
7564 parameter bindings are okay, FALSE otherwise. */
7565 bool
7567 {
7571 /* We're dealing with template parms in this process. */
7577 {
7582 {
7587 {
7588 /* Look inside the argument pack. */
7591 }
7594 {
7598 /* Extract the next argument from the argument
7599 pack. */
7603 /* Look at the pattern of the pack expansion. */
7606 /* Extract the template parameters from the template
7607 argument. */
7613 /* Verify that we can coerce the template template
7614 parameters from the template argument to the template
7615 parameter. This requires an exact match. */
7617 && !coerce_template_template_parms
7619 targ_parms,
7620 tf_none,
7621 tparm,
7622 targs))
7623 {
7626 }
7627 }
7628 }
7629 }
7631 out:
7635 }
7637 /* Since type attributes aren't mangled, we need to strip them from
7638 template type arguments. */
7640 static tree
7642 {
7652 }
7654 /* And from inside dependent non-type arguments like sizeof(Type). */
7656 static tree
7658 {
7668 }
7670 // A template declaration can be substituted for a constrained
7671 // template template parameter only when the argument is more
7672 // constrained than the parameter.
7673 static bool
7675 {
7678 /* For now, allow constrained template template arguments
7679 and unconstrained template template parameters. */
7685 // If the template parameter is constrained, we need to rewrite its
7686 // constraints in terms of the ARG's template parameters. This ensures
7687 // that all of the template parameter types will have the same depth.
7688 //
7689 // Note that this is only valid when coerce_template_template_parm is
7690 // true for the innermost template parameters of PARM and ARG. In other
7691 // words, because coercion is successful, this conversion will be valid.
7693 {
7700 }
7703 }
7705 // Convert a placeholder argument into a binding to the original
7706 // parameter. The original parameter is saved as the TREE_TYPE of
7707 // ARG.
7710 {
7713 }
7715 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7716 because one of them is dependent. But we need to represent the
7717 conversion for the benefit of cp_tree_equal. */
7719 static tree
7721 {
7722 /* Auto parms get no conversion. */
7725 /* We don't need or want to add this conversion now if we're going to use the
7726 argument for deduction. */
7738 }
7740 /* Convert the indicated template ARG as necessary to match the
7741 indicated template PARM. Returns the converted ARG, or
7742 error_mark_node if the conversion was unsuccessful. Error and
7743 warning messages are issued under control of COMPLAIN. This
7744 conversion is for the Ith parameter in the parameter list. ARGS is
7745 the full set of template arguments deduced so far. */
7747 static tree
7749 tree arg,
7750 tree args,
7751 tsubst_flags_t complain,
7753 tree in_decl)
7754 {
7755 tree orig_arg;
7756 tree val;
7762 /* Trivially convert placeholders. */
7771 {
7772 /* The template argument was the name of some
7773 member function. That's usually
7774 invalid, but static members are OK. In any
7775 case, grab the underlying fields/functions
7776 and issue an error later if required. */
7779 }
7787 /* When determining whether an argument pack expansion is a template,
7788 look at the pattern. */
7792 /* Deal with an injected-class-name used as a template template arg. */
7794 {
7797 {
7807 }
7808 }
7810 is_tmpl_type =
7826 {
7828 {
7832 }
7835 "to refer to a type member of a template parameter, "
7840 typename_type,
7841 complain);
7844 }
7846 {
7848 {
7850 {
7862 else
7865 }
7866 }
7868 }
7870 {
7872 {
7879 else
7882 }
7884 }
7887 /* We already did the appropriate conversion when packing args. */
7890 {
7892 {
7894 /* The number of argument required is not known yet.
7895 Just accept it for now. */
7897 else
7898 {
7900 tree argparm;
7902 /* Strip alias templates that are equivalent to another
7903 template. */
7909 args))
7910 {
7913 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7914 TEMPLATE_DECL. */
7916 {
7921 }
7922 }
7923 else
7924 {
7926 {
7933 }
7936 }
7938 // Check that the constraints are compatible before allowing the
7939 // substitution.
7942 {
7944 {
7950 }
7952 }
7953 }
7954 }
7955 else
7957 /* We only form one instance of each template specialization.
7958 Therefore, if we use a non-canonical variant (i.e., a
7959 typedef), any future messages referring to the type will use
7960 the typedef, which is confusing if those future uses do not
7961 themselves also use the typedef. */
7964 }
7965 else
7966 {
7971 /* We don't have enough levels of args to do any substitution. This
7974 {
7978 }
7979 else
7987 /* We used to call digest_init here. However, digest_init
7988 will report errors, which we don't want when complain
7989 is zero. More importantly, digest_init will try too
7990 hard to convert things: for example, `0' should not be
7991 converted to pointer type at this point according to
7992 the standard. Accepting this is not merely an
7993 extension, since deciding whether or not these
7994 conversions can occur is part of determining which
7995 function template to call, or whether a given explicit
7996 argument specification is valid. */
7998 else
7999 {
8002 }
8012 {
8013 /* Reject template arguments that are references to built-in
8014 functions with no library fallbacks. */
8023 }
8026 {
8027 /* Strip typedefs from the SCOPE_REF. */
8030 complain);
8033 }
8034 }
8037 }
8039 /* Coerces the remaining template arguments in INNER_ARGS (from
8040 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8041 Returns the coerced argument pack. PARM_IDX is the position of this
8042 parameter in the template parameter list. ARGS is the original
8043 template argument list. */
8044 static tree
8047 tree args,
8048 tree inner_args,
8050 tree new_args,
8052 tree in_decl,
8053 tsubst_flags_t complain)
8054 {
8057 tree packed_args;
8058 tree argument_pack;
8065 {
8066 /* When the template parameter is a non-type template parameter pack
8067 or template template parameter pack whose type or template
8068 parameters use parameter packs, we know exactly how many arguments
8069 we are looking for. Build a vector of the instantiated decls for
8070 these template parameters in PACKED_PARMS. */
8071 /* We can't use make_pack_expansion here because it would interpret a
8072 _DECL as a use rather than a declaration. */
8086 /* If we're doing a partial instantiation of a member template,
8087 verify that all of the types used for the non-type
8088 template parameter pack are, in fact, valid for non-type
8089 template parameters. */
8092 {
8095 {
8099 }
8100 /* We don't know how many args we have yet, just
8101 use the unconverted ones for now. */
8103 }
8106 }
8107 /* Check if we have a placeholder pack, which indicates we're
8108 in the context of a introduction list. In that case we want
8109 to match this pack to the single placeholder. */
8113 {
8116 }
8117 else
8120 /* Convert the remaining arguments, which will be a part of the
8121 parameter pack "parm". */
8124 {
8130 {
8131 /* Once we've packed as many args as we have types, stop. */
8135 /* We don't know how many args we have yet, just
8136 use the unconverted ones for now. */
8138 else
8140 }
8143 {
8146 }
8147 else
8150 in_decl);
8154 }
8158 {
8163 }
8168 else
8169 {
8172 }
8179 }
8181 /* Returns the number of pack expansions in the template argument vector
8182 ARGS. */
8184 static int
8186 {
8191 {
8195 }
8197 }
8199 /* Convert all template arguments to their appropriate types, and
8200 return a vector containing the innermost resulting template
8201 arguments. If any error occurs, return error_mark_node. Error and
8202 warning messages are issued under control of COMPLAIN.
8204 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8205 for arguments not specified in ARGS. Otherwise, if
8206 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8207 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8208 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8209 ARGS. */
8211 static tree
8213 tree args,
8214 tree in_decl,
8215 tsubst_flags_t complain,
8218 {
8220 tree orig_inner_args;
8221 tree inner_args;
8222 tree new_args;
8223 tree new_inner_args;
8227 /* When used as a boolean value, indicates whether this is a
8228 variadic template parameter list. Since it's an int, we can also
8229 subtract it from nparms to get the number of non-variadic
8230 parameters. */
8235 /* Adjustment to nparms for fixed parameter packs. */
8240 /* Likewise for parameters with default arguments. */
8248 /* Determine if there are any parameter packs or default arguments. */
8250 {
8258 }
8261 /* If there are no parameters that follow a parameter pack, we need to
8262 expand any argument packs so that we can deduce a parameter pack from
8263 some non-packed args followed by an argument pack, as in variadic85.C.
8264 If there are such parameters, we need to leave argument packs intact
8265 so the arguments are assigned properly. This can happen when dealing
8266 with a nested class inside a partial specialization of a class
8267 template, as in variadic92.C, or when deducing a template parameter pack
8268 from a sub-declarator, as in variadic114.C. */
8272 /* Count any pack expansion args. */
8278 && require_all_args
8279 && !variadic_args_p
8280 && (!use_default_args
8283 {
8284 bad_nargs:
8286 {
8288 {
8292 }
8293 else
8300 }
8303 }
8304 /* We can't pass a pack expansion to a non-pack parameter of an alias
8305 template (DR 1430). */
8309 && variadic_args_p
8311 {
8313 {
8315 {
8321 {
8324 "pack expansion argument for non-pack parameter "
8326 else
8328 "pack expansion argument for non-pack parameter "
8332 }
8333 }
8335 found:;
8336 }
8338 }
8340 /* We need to evaluate the template arguments, even though this
8341 template-id may be nested within a "sizeof". */
8350 {
8351 tree arg;
8352 tree parm;
8354 /* Get the Ith template parameter. */
8358 {
8361 }
8363 /* Calculate the next argument. */
8366 else
8371 {
8372 /* Some arguments will be placed in the
8373 template parameter pack PARM. */
8380 {
8381 /* We don't know how many args we have yet, just use the
8382 unconverted (and still packed) ones for now. */
8386 }
8390 /* Store this argument. */
8392 {
8393 lost++;
8394 /* We are done with all of the arguments. */
8397 }
8398 else
8399 {
8403 {
8406 }
8407 }
8410 }
8412 {
8414 {
8415 /* "If every valid specialization of a variadic template
8416 requires an empty template parameter pack, the template is
8417 ill-formed, no diagnostic required." So check that the
8418 pattern works with this parameter. */
8423 in_decl);
8425 {
8430 }
8432 /* Recover from missing typename. */
8436 /* We don't know how many args we have yet, just
8437 use the unconverted ones for now. */
8441 }
8442 }
8444 {
8445 /* There must be a default arg in this case. */
8448 /* The position of the first default template argument,
8449 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8450 Record that. */
8454 }
8455 else
8459 {
8462 }
8464 {
8465 /* This can occur if there was an error in the template
8466 parameter list itself (which we would already have
8467 reported) that we are trying to recover from, e.g., a class
8468 template with a parameter list such as
8469 template<typename..., typename> (cpp0x/variadic150.C). */
8472 /* This can also happen with a fixed parameter pack (71834). */
8475 }
8476 else
8482 lost++;
8484 }
8489 {
8490 /* If we had fixed parameter packs, we didn't know how many arguments we
8491 actually needed earlier; now we do. */
8495 }
8498 {
8499 /* We had some pack expansion arguments that will only work if the packs
8500 are empty, but wait until instantiation time to complain.
8501 See variadic-ttp3.C. */
8511 }
8514 {
8517 }
8524 }
8526 /* Convert all template arguments to their appropriate types, and
8527 return a vector containing the innermost resulting template
8528 arguments. If any error occurs, return error_mark_node. Error and
8529 warning messages are not issued.
8531 Note that no function argument deduction is performed, and default
8532 arguments are used to fill in unspecified arguments. */
8533 tree
8535 {
8537 }
8539 /* Convert all template arguments to their appropriate type, and
8540 instantiate default arguments as needed. This returns a vector
8541 containing the innermost resulting template arguments, or
8542 error_mark_node if unsuccessful. */
8543 tree
8545 tsubst_flags_t complain)
8546 {
8548 }
8550 /* Like coerce_template_parms. If PARMS represents all template
8551 parameters levels, this function returns a vector of vectors
8552 representing all the resulting argument levels. Note that in this
8553 case, only the innermost arguments are coerced because the
8554 outermost ones are supposed to have been coerced already.
8556 Otherwise, if PARMS represents only (the innermost) vector of
8557 parameters, this function returns a vector containing just the
8558 innermost resulting arguments. */
8560 static tree
8562 tree args,
8563 tree in_decl,
8564 tsubst_flags_t complain,
8567 {
8570 tree coerced_args;
8573 {
8575 tree level;
8581 {
8582 tree l;
8586 require_all_args,
8587 use_default_args);
8588 else
8595 }
8596 }
8597 else
8600 require_all_args,
8601 use_default_args);
8603 }
8605 /* Returns 1 if template args OT and NT are equivalent. */
8607 int
8609 {
8618 /* For member templates */
8627 {
8644 }
8648 {
8651 /* Don't treat an alias template specialization with dependent
8652 arguments as equivalent to its underlying type when used as a
8653 template argument; we need them to be distinct so that we
8654 substitute into the specialization arguments at instantiation
8655 time. And aliases can't be equivalent without being ==, so
8656 we don't need to look any deeper.
8658 During partial ordering, however, we need to treat them normally so
8659 that we can order uses of the same alias with different
8660 cv-qualification (79960). */
8664 else
8666 }
8669 else
8670 {
8671 /* Try to treat a template non-type argument that has been converted
8672 to the parameter type as equivalent to one that hasn't yet. */
8685 }
8686 }
8688 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8689 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8690 NEWARG_PTR with the offending arguments if they are non-NULL. */
8692 int
8696 {
8709 {
8714 {
8720 }
8721 }
8723 }
8727 {
8729 }
8731 /* Implement a freelist interface for objects of type T.
8733 Head is a separate object, rather than a regular member, so that we
8734 can define it as a GTY deletable pointer, which is highly
8735 desirable. A data member could be declared that way, but then the
8736 containing object would implicitly get GTY((user)), which would
8737 prevent us from instantiating freelists as global objects.
8738 Although this way we can create freelist global objects, they're
8739 such thin wrappers that instantiating temporaries at every use
8740 loses nothing and saves permanent storage for the freelist object.
8742 Member functions next, anew, poison and reinit have default
8743 implementations that work for most of the types we're interested
8744 in, but if they don't work for some type, they should be explicitly
8745 specialized. See the comments before them for requirements, and
8746 the example specializations for the tree_list_freelist. */
8748 class freelist
8749 {
8750 /* Return the next object in a chain. We could just do type
8751 punning, but if we access the object with its underlying type, we
8752 avoid strict-aliasing trouble. This needs only work between
8753 poison and reinit. */
8756 /* Return a newly allocated, uninitialized or minimally-initialized
8757 object of type T. Any initialization performed by anew should
8758 either remain across the life of the object and the execution of
8759 poison, or be redone by reinit. */
8762 /* Optionally scribble all over the bits holding the object, so that
8763 they become (mostly?) uninitialized memory. This is called while
8764 preparing to make the object part of the free list. */
8769 #ifdef ENABLE_GC_CHECKING
8770 /* Poison the data, to indicate the data is garbage. */
8773 #endif
8774 /* Let valgrind know the object is free. */
8777 /* Let valgrind know the next portion of the object is available,
8778 but uninitialized. */
8780 }
8782 /* Bring an object that underwent at least one lifecycle after anew
8783 and before the most recent free and poison, back to a usable
8784 state, reinitializing whatever is needed for it to be
8785 functionally equivalent to an object just allocated and returned
8786 by anew. This may poison or clear the next field, used by
8787 freelist housekeeping after poison was called. */
8791 #ifdef ENABLE_GC_CHECKING
8793 #endif
8794 /* Let valgrind know the entire object is available, but
8795 uninitialized. */
8797 }
8799 /* Reference a GTY-deletable pointer that points to the first object
8800 in the free list proper. */
8803 /* Construct a freelist object chaining objects off of HEAD. */
8806 /* Add OBJ to the free object list. The former head becomes OBJ's
8807 successor. */
8809 {
8813 }
8815 /* Take an object from the free list, if one is available, or
8816 allocate a new one. Objects taken from the free list should be
8817 regarded as filled with garbage, except for bits that are
8818 configured to be preserved across free and alloc. */
8820 {
8822 {
8827 }
8828 else
8830 }
8831 };
8833 /* Explicitly specialize the interfaces for freelist<tree_node>: we
8834 want to allocate a TREE_LIST using the usual interface, and ensure
8835 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
8836 build_tree_list logic in reinit, so this could go out of sync. */
8840 {
8842 }
8844 inline tree
8846 {
8848 }
8852 {
8858 #ifdef ENABLE_GC_CHECKING
8861 /* Poison the data, to indicate the data is garbage. */
8864 #endif
8865 /* Let valgrind know the object is free. */
8867 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
8871 #ifdef ENABLE_GC_CHECKING
8873 /* Keep TREE_CHAIN functional. */
8875 #else
8877 #endif
8878 }
8882 {
8885 #ifdef ENABLE_GC_CHECKING
8889 #endif
8891 /* Let valgrind know the entire object is available, but
8892 uninitialized. */
8895 #ifdef ENABLE_GC_CHECKING
8897 #else
8899 #endif
8900 }
8902 /* Point to the first object in the TREE_LIST freelist. */
8904 /* Return the/an actual TREE_LIST freelist. */
8907 {
8909 }
8911 /* Point to the first object in the tinst_level freelist. */
8913 /* Return the/an actual tinst_level freelist. */
8916 {
8918 }
8920 /* Point to the first object in the pending_template freelist. */
8922 /* Return the/an actual pending_template freelist. */
8925 {
8927 }
8929 /* Build the TREE_LIST object out of a split list, store it
8930 permanently, and return it. */
8931 tree
8933 {
8942 }
8946 /* Increment OBJ's refcount unless it is already infinite. */
8949 {
8953 }
8955 /* Release storage for OBJ and node, if it's a TREE_LIST. */
8956 void
8958 {
8962 }
8964 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
8965 OBJ's DECL and OBJ, and start over with the tinst_level object that
8966 used to be referenced by OBJ's NEXT. */
8967 static void
8969 {
8973 {
8977 }
8978 }
8980 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
8981 and of the former PTR. Omitting the second argument is equivalent
8982 to passing (T*)NULL; this is allowed because passing the
8983 zero-valued integral constant NULL confuses type deduction and/or
8984 overload resolution. */
8986 static void
8988 {
8992 }
8994 static void
8996 {
9006 /* We are called both from instantiate_decl, where we've already had a
9007 tinst_level pushed, and instantiate_template, where we haven't.
9008 Compensate. */
9010 level = !current_tinst_level
9022 else
9031 }
9034 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9035 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9036 documentation for TEMPLATE_ID_EXPR. */
9038 tree
9040 {
9041 tree type;
9049 {
9052 }
9055 {
9057 unknown_type_node,
9059 arglist);
9061 }
9068 }
9070 /* Within the scope of a template class S<T>, the name S gets bound
9071 (in build_self_reference) to a TYPE_DECL for the class, not a
9072 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9073 or one of its enclosing classes, and that type is a template,
9074 return the associated TEMPLATE_DECL. Otherwise, the original
9075 DECL is returned.
9077 Also handle the case when DECL is a TREE_LIST of ambiguous
9078 injected-class-names from different bases. */
9080 tree
9082 {
9086 /* DR 176: A lookup that finds an injected-class-name (10.2
9087 [class.member.lookup]) can result in an ambiguity in certain cases
9088 (for example, if it is found in more than one base class). If all of
9089 the injected-class-names that are found refer to specializations of
9090 the same class template, and if the name is followed by a
9091 template-argument-list, the reference refers to the class template
9092 itself and not a specialization thereof, and is not ambiguous. */
9094 {
9097 {
9103 }
9106 else
9108 }
9114 }
9116 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9117 parameters, find the desired type.
9119 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9121 IN_DECL, if non-NULL, is the template declaration we are trying to
9122 instantiate.
9124 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9125 the class we are looking up.
9127 Issue error and warning messages under control of COMPLAIN.
9129 If the template class is really a local class in a template
9130 function, then the FUNCTION_CONTEXT is the function in which it is
9131 being instantiated.
9133 ??? Note that this function is currently called *twice* for each
9134 template-id: the first time from the parser, while creating the
9135 incomplete type (finish_template_type), and the second type during the
9136 real instantiation (instantiate_template_class). This is surely something
9137 that we want to avoid. It also causes some problems with argument
9138 coercion (see convert_nontype_argument for more information on this). */
9140 static tree
9143 {
9145 tree t;
9148 spec_entry elt;
9149 hashval_t hash;
9152 {
9156 else
9157 {
9164 }
9167 }
9169 {
9172 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9173 an implicit typename for the second A. Deal with it. */
9178 {
9181 }
9182 }
9185 {
9188 }
9190 {
9194 }
9196 {
9199 }
9201 /* Issue an error message if we didn't find a template. */
9203 {
9207 }
9210 /* Make sure it's a user visible template, if it was named by
9211 the user. */
9214 {
9216 {
9220 }
9222 }
9226 /* An alias that just changes the name of a template is equivalent to the
9227 other template, so if any of the arguments are pack expansions, strip
9228 the alias to avoid problems with a pack expansion passed to a non-pack
9229 alias template parameter (DR 1430). */
9234 {
9235 tree parm;
9244 }
9245 else
9246 {
9248 tree gen_tmpl;
9249 tree type_decl;
9257 /* An error occurred while building the template TEMPL, and a
9258 diagnostic has most certainly been emitted for that
9259 already. Let's propagate that error. */
9268 {
9269 /* We've been given an incomplete set of template arguments.
9270 For example, given:
9272 template <class T> struct S1 {
9273 template <class U> struct S2 {};
9274 template <class U> struct S2<U*> {};
9275 };
9277 we will be called with an ARGLIST of `U*', but the
9278 TEMPLATE will be `template <class T> template
9279 <class U> struct S1<T>::S2'. We must fill in the missing
9280 arguments. */
9284 }
9286 /* Now we should have enough arguments. */
9289 /* From here on, we're only interested in the most general
9290 template. */
9292 /* Calculate the BOUND_ARGS. These will be the args that are
9293 actually tsubst'd into the definition to create the
9294 instantiation. */
9296 complain,
9301 /* We were unable to bind the arguments. */
9304 /* In the scope of a template class, explicit references to the
9305 template class refer to the type of the template, not any
9306 instantiation of it. For example, in:
9308 template <class T> class C { void f(C<T>); }
9310 the `C<T>' is just the same as `C'. Outside of the
9311 class, however, such a reference is an instantiation. */
9315 {
9320 }
9322 /* If we already have this specialization, return it. */
9332 /* If the the template's constraints are not satisfied,
9333 then we cannot form a valid type.
9335 Note that the check is deferred until after the hash
9336 lookup. This prevents redundant checks on previously
9337 instantiated specializations. */
9339 {
9341 {
9344 }
9346 }
9350 /* If the deduced arguments are invalid, then the binding
9351 failed. */
9355 complain))
9362 {
9367 }
9377 /* Create the type. */
9379 {
9380 /* The user referred to a specialization of an alias
9381 template represented by GEN_TMPL.
9383 [temp.alias]/2 says:
9385 When a template-id refers to the specialization of an
9386 alias template, it is equivalent to the associated
9387 type obtained by substitution of its
9388 template-arguments for the template-parameters in the
9389 type-id of the alias template. */
9392 /* Note that the call above (by indirectly calling
9393 register_specialization in tsubst_decl) registers the
9394 TYPE_DECL representing the specialization of the alias
9395 template. So next time someone substitutes ARGLIST for
9396 the template parms into the alias template (GEN_TMPL),
9397 she'll get that TYPE_DECL back. */
9401 }
9403 {
9405 {
9416 }
9417 else
9418 {
9419 /* We don't want to call start_enum for this type, since
9420 the values for the enumeration constants may involve
9421 template parameters. And, no one should be interested
9422 in the enumeration constants for such a type. */
9425 }
9429 }
9431 {
9432 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9433 instantiated here. */
9441 /* A local class. Make sure the decl gets registered properly. */
9448 /* This instantiation is another name for the primary
9449 template type. Set the TYPE_CANONICAL field
9450 appropriately. */
9453 /* Some of the template arguments require structural
9454 equality testing, so this template class requires
9455 structural equality testing. */
9457 }
9458 else
9461 /* If we called start_enum or pushtag above, this information
9462 will already be set up. */
9464 {
9471 }
9472 else
9476 {
9482 {
9485 }
9486 }
9490 {
9494 {
9495 tree attributes
9503 }
9504 }
9506 /* Let's consider the explicit specialization of a member
9507 of a class template specialization that is implicitly instantiated,
9508 e.g.:
9509 template<class T>
9510 struct S
9511 {
9512 template<class U> struct M {}; //#0
9513 };
9515 template<>
9516 template<>
9517 struct S<int>::M<char> //#1
9518 {
9519 int i;
9520 };
9521 [temp.expl.spec]/4 says this is valid.
9523 In this case, when we write:
9524 S<int>::M<char> m;
9526 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9527 the one of #0.
9529 When we encounter #1, we want to store the partial instantiation
9530 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9532 For all cases other than this "explicit specialization of member of a
9533 class template", we just want to store the most general template into
9534 the CLASSTYPE_TI_TEMPLATE of M.
9536 This case of "explicit specialization of member of a class template"
9537 only happens when:
9538 1/ the enclosing class is an instantiation of, and therefore not
9539 the same as, the context of the most general template, and
9540 2/ we aren't looking at the partial instantiation itself, i.e.
9541 the innermost arguments are not the same as the innermost parms of
9542 the most general template.
9544 So it's only when 1/ and 2/ happens that we want to use the partial
9545 instantiation of the member template in lieu of its most general
9546 template. */
9550 /* the enclosing class must be an instantiation... */
9553 {
9557 tree partial_inst_args =
9564 use_partial_inst_tmpl =
9565 /*...and we must not be looking at the partial instantiation
9566 itself. */
9568 partial_inst_args);
9569 }
9572 /* This case is easy; there are no member templates involved. */
9574 else
9575 {
9576 /* This is a full instantiation of a member template. Find
9577 the partial instantiation of which this is an instance. */
9579 /* Temporarily reduce by one the number of levels in the ARGLIST
9580 so as to avoid comparing the last set of arguments. */
9584 /* FOUND is either a proper class type, or an alias
9585 template specialization. In the later case, it's a
9586 TYPE_DECL, resulting from the substituting of arguments
9587 for parameters in the TYPE_DECL of the alias template
9588 done earlier. So be careful while getting the template
9589 of FOUND. */
9591 ? found
9595 }
9597 // Build template info for the new specialization.
9606 /* Note this use of the partial instantiation so we can check it
9607 later in maybe_process_partial_specialization. */
9614 /* Now that the type has been registered on the instantiations
9615 list, we set up the enumerators. Because the enumeration
9616 constants may involve the enumeration type itself, we make
9617 sure to register the type first, and then create the
9618 constants. That way, doing tsubst_expr for the enumeration
9619 constants won't result in recursive calls here; we'll find
9620 the instantiation and exit above. */
9624 /* If the type makes use of template parameters, the
9625 code that generates debugging information will crash. */
9628 /* Possibly limit visibility based on template args. */
9635 }
9636 }
9638 /* Wrapper for lookup_template_class_1. */
9640 tree
9643 {
9644 tree ret;
9650 }
9652 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9654 tree
9656 {
9657 /* The type of the expression is NULL_TREE since the template-id could refer
9658 to an explicit or partial specialization. */
9661 /* Except that concepts are always bool. */
9664 }
9666 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9668 tree
9670 {
9674 /* We never want to return a VAR_DECL for a variable concept, since they
9675 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9690 {
9692 {
9695 }
9697 }
9699 /* If a template-id refers to a specialization of a variable
9700 concept, then the expression is true if and only if the
9701 concept's constraints are satisfied by the given template
9702 arguments.
9704 NOTE: This is an extension of Concepts Lite TS that
9705 allows constraints to be used in expressions. */
9707 {
9710 }
9713 }
9715 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9716 TARGS template args, and instantiate it if it's not dependent. */
9718 tree
9720 tsubst_flags_t complain)
9721 {
9724 {
9727 }
9730 }
9732 \f
9733 struct pair_fn_data
9734 {
9735 tree_fn_t fn;
9736 tree_fn_t any_fn;
9738 /* True when we should also visit template parameters that occur in
9739 non-deduced contexts. */
9742 };
9744 /* Called from for_each_template_parm via walk_tree. */
9746 static tree
9748 {
9755 #define WALK_SUBTREE(NODE) \
9756 do \
9757 { \
9758 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9759 pfd->include_nondeduced_p, \
9760 pfd->any_fn); \
9761 if (result) goto out; \
9762 } \
9763 while (0)
9773 {
9777 /* Fall through. */
9783 else
9793 /* Since we're not going to walk subtrees, we have to do this
9794 explicitly here. */
9796 /* Fall through. */
9799 /* Check the return type. */
9802 /* Check the parameter types. Since default arguments are not
9803 instantiated until they are needed, the TYPE_ARG_TYPES may
9804 contain expressions that involve template parameters. But,
9805 no-one should be looking at them yet. And, once they're
9806 instantiated, they don't contain template parameters, so
9807 there's no point in looking at them then, either. */
9808 {
9809 tree parm;
9814 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9815 want walk_tree walking into them itself. */
9817 }
9820 {
9824 }
9843 /* Fall through. */
9855 /* Record template parameters such as `T' inside `TT<T>'. */
9857 /* Fall through. */
9869 /* A template template parameter is encountered. */
9873 /* Already substituted template template parameter */
9878 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9879 partial instantiation. */
9891 /* If there's no type, then this thing must be some expression
9892 involving template parameters. */
9914 }
9916 #undef WALK_SUBTREE
9918 /* We didn't find any template parameters we liked. */
9919 out:
9921 }
9923 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9924 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9925 call FN with the parameter and the DATA.
9926 If FN returns nonzero, the iteration is terminated, and
9927 for_each_template_parm returns 1. Otherwise, the iteration
9928 continues. If FN never returns a nonzero value, the value
9929 returned by for_each_template_parm is 0. If FN is NULL, it is
9930 considered to be the function which always returns 1.
9932 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9933 parameters that occur in non-deduced contexts. When false, only
9934 visits those template parameters that can be deduced. */
9936 static tree
9940 tree_fn_t any_fn)
9941 {
9943 tree result;
9945 /* Set up. */
9951 /* Walk the tree. (Conceptually, we would like to walk without
9952 duplicates, but for_each_template_parm_r recursively calls
9953 for_each_template_parm, so we would need to reorganize a fair
9954 bit to use walk_tree_without_duplicates, so we keep our own
9955 visited list.) */
9958 else
9961 for_each_template_parm_r,
9965 /* Clean up. */
9967 {
9970 }
9973 }
9975 /* Returns true if T depends on any template parameter. */
9977 int
9979 {
10009 else
10010 {
10013 }
10018 }
10020 /* Returns true iff current_function_decl is an incompletely instantiated
10021 template. Useful instead of processing_template_decl because the latter
10022 is set to 0 during instantiate_non_dependent_expr. */
10024 bool
10026 {
10035 }
10037 /* Returns true if T depends on any template parameter with level LEVEL. */
10039 bool
10041 {
10044 }
10046 /* Returns true if the signature of DECL depends on any template parameter from
10047 its enclosing class. */
10049 bool
10051 {
10061 template_parm_outer_level,
10071 }
10073 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10074 ill-formed translation unit, i.e. a variable or function that isn't
10075 usable in a constant expression. */
10079 {
10084 }
10086 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10087 neglectable and instantiated from within an erroneous instantiation. */
10089 static bool
10091 {
10102 }
10110 /* We're starting to instantiate D; record the template instantiation context
10111 at LOC for diagnostics and to restore it later. */
10113 static bool
10115 {
10119 {
10120 /* Tell error.c not to try to instantiate any templates. */
10123 "template instantiation depth exceeds maximum of %d"
10125 max_tinst_depth);
10127 }
10129 /* If the current instantiation caused problems, don't let it instantiate
10130 anything else. Do allow deduction substitution and decls usable in
10131 constant expressions. */
10135 /* When not -quiet, dump template instantiations other than functions, since
10136 announce_function will take care of those. */
10157 }
10159 /* We're starting substitution of TMPL<ARGS>; record the template
10160 substitution context for diagnostics and to restore it later. */
10162 static bool
10164 {
10166 }
10168 /* We're starting to instantiate D; record INPUT_LOCATION and the
10169 template instantiation context for diagnostics and to restore it
10170 later. */
10172 bool
10174 {
10176 }
10178 /* Likewise, but record LOC as the program location. */
10180 bool
10182 {
10185 }
10187 /* We're done instantiating this template; return to the instantiation
10188 context. */
10190 void
10192 {
10193 /* Restore the filename and line number stashed away when we started
10194 this instantiation. */
10198 }
10200 /* We're instantiating a deferred template; restore the template
10201 instantiation context in which the instantiation was requested, which
10202 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
10204 static tree
10206 {
10218 }
10220 /* Returns the TINST_LEVEL which gives the original instantiation
10221 context. */
10225 {
10231 }
10233 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
10234 vector of template arguments, as for tsubst.
10236 Returns an appropriate tsubst'd friend declaration. */
10238 static tree
10240 {
10241 tree new_friend;
10246 /* This was a friend declared with an explicit template
10247 argument list, e.g.:
10249 friend void f<>(T);
10251 to indicate that f was a template instantiation, not a new
10252 function declaration. Now, we have to figure out what
10253 instantiation of what template. */
10254 {
10256 tree new_args;
10257 tree tmpl;
10260 /* Friend functions are looked up in the containing namespace scope.
10261 We must enter that scope, to avoid finding member functions of the
10262 current class with same name. */
10277 tsk_none);
10279 }
10283 /* The NEW_FRIEND will look like an instantiation, to the
10284 compiler, but is not an instantiation from the point of view of
10285 the language. For example, we might have had:
10287 template <class T> struct S {
10288 template <class U> friend void f(T, U);
10289 };
10291 Then, in S<int>, template <class U> void f(int, U) is not an
10292 instantiation of anything. */
10298 {
10302 }
10304 /* The mangled name for the NEW_FRIEND is incorrect. The function
10305 is not a template instantiation and should not be mangled like
10306 one. Therefore, we forget the mangling here; we'll recompute it
10307 later if we need it. */
10309 {
10312 }
10315 {
10316 tree old_decl;
10317 tree new_friend_template_info;
10318 tree new_friend_result_template_info;
10319 tree ns;
10322 /* We must save some information from NEW_FRIEND before calling
10323 duplicate decls since that function will free NEW_FRIEND if
10324 possible. */
10326 new_friend_is_defn =
10331 {
10332 /* This declaration is a `primary' template. */
10335 new_friend_result_template_info
10337 }
10338 else
10341 /* Inside pushdecl_namespace_level, we will push into the
10342 current namespace. However, the friend function should go
10343 into the namespace of the template. */
10353 {
10354 /* This new friend declaration matched an existing
10355 declaration. For example, given:
10357 template <class T> void f(T);
10358 template <class U> class C {
10359 template <class T> friend void f(T) {}
10360 };
10362 the friend declaration actually provides the definition
10363 of `f', once C has been instantiated for some type. So,
10364 old_decl will be the out-of-class template declaration,
10365 while new_friend is the in-class definition.
10367 But, if `f' was called before this point, the
10368 instantiation of `f' will have DECL_TI_ARGS corresponding
10369 to `T' but not to `U', references to which might appear
10370 in the definition of `f'. Previously, the most general
10371 template for an instantiation of `f' was the out-of-class
10372 version; now it is the in-class version. Therefore, we
10373 run through all specialization of `f', adding to their
10374 DECL_TI_ARGS appropriately. In particular, they need a
10375 new set of outer arguments, corresponding to the
10376 arguments for this class instantiation.
10378 The same situation can arise with something like this:
10380 friend void f(int);
10381 template <class T> class C {
10382 friend void f(T) {}
10383 };
10385 when `C<int>' is instantiated. Now, `f(int)' is defined
10386 in the class. */
10389 /* On the other hand, if the in-class declaration does
10390 *not* provide a definition, then we don't want to alter
10391 existing definitions. We can just leave everything
10392 alone. */
10393 ;
10394 else
10395 {
10399 /* Overwrite whatever template info was there before, if
10400 any, with the new template information pertaining to
10401 the declaration. */
10405 {
10406 /* We should have called reregister_specialization in
10407 duplicate_decls. */
10412 /* Instantiate it if the global has already been used. */
10416 }
10417 else
10418 {
10419 tree t;
10421 /* Indicate that the old function template is a partial
10422 instantiation. */
10430 /* Reassign any specializations already in the hash table
10431 to the new more general template, and add the
10432 additional template args. */
10436 {
10438 spec_entry elt;
10450 register_specialization
10453 }
10455 }
10456 }
10458 /* The information from NEW_FRIEND has been merged into OLD_DECL
10459 by duplicate_decls. */
10461 }
10462 }
10463 else
10464 {
10468 /* In the code
10469 template <class T> class C {
10470 template <class U> friend void C1<U>::f (); // case 1
10471 friend void C2<T>::f (); // case 2
10472 };
10473 we only need to make sure CONTEXT is a complete type for
10474 case 2. To distinguish between the two cases, we note that
10475 CONTEXT of case 1 remains dependent type after tsubst while
10476 this isn't true for case 2. */
10486 {
10488 /* do_friend adds the TEMPLATE_DECL for any member friend
10489 template even if it isn't a member template, i.e.
10490 template <class T> friend A<T>::f();
10491 Look through it in that case. */
10495 /* Check to see that the declaration is really present, and,
10496 possibly obtain an improved declaration. */
10501 }
10502 }
10505 }
10507 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10508 template arguments, as for tsubst.
10510 Returns an appropriate tsubst'd friend type or error_mark_node on
10511 failure. */
10513 static tree
10515 {
10516 tree tmpl;
10519 {
10522 }
10527 else
10535 {
10536 /* The friend template has already been declared. Just
10537 check to see that the declarations match, and install any new
10538 default parameters. We must tsubst the default parameters,
10539 of course. We only need the innermost template parameters
10540 because that is all that redeclare_class_template will look
10541 at. */
10544 {
10552 }
10553 }
10554 else
10555 {
10556 /* The friend template has not already been declared. In this
10557 case, the instantiation of the template class will cause the
10558 injection of this template into the namespace scope. */
10562 {
10563 /* The new TMPL is not an instantiation of anything, so we
10564 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10565 for the new type because that is supposed to be the
10566 corresponding template decl, i.e., TMPL. */
10573 /* It is hidden. */
10578 /* Inject this template into the enclosing namspace scope. */
10580 }
10581 }
10585 else
10589 }
10591 /* Returns zero if TYPE cannot be completed later due to circularity.
10592 Otherwise returns one. */
10594 static int
10596 {
10606 else
10608 }
10613 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10614 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10616 static tree
10619 {
10628 {
10635 clauses
10639 else
10641 }
10642 /* If the first attribute argument is an identifier, don't
10643 pass it through tsubst. Attributes like mode, format,
10644 cleanup and several target specific attributes expect it
10645 unmodified. */
10647 {
10648 tree chain
10653 }
10655 {
10656 /* An attribute pack expansion. */
10665 {
10669 }
10671 }
10672 else
10679 }
10681 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10682 unchanged or a new TREE_LIST chain. */
10684 static tree
10687 {
10692 {
10696 }
10700 {
10703 {
10706 {
10712 }
10713 }
10715 }
10718 }
10720 /* Apply any attributes which had to be deferred until instantiation
10721 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10722 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10724 static void
10727 {
10729 tree t;
10736 {
10740 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10741 to our attributes parameter. */
10743 }
10744 else
10745 {
10747 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10748 lookup_template_class_1, and should be preserved. */
10752 }
10756 {
10760 }
10764 {
10769 {
10772 {
10778 }
10779 else
10781 }
10784 }
10785 }
10787 /* Perform (or defer) access check for typedefs that were referenced
10788 from within the template TMPL code.
10789 This is a subroutine of instantiate_decl and instantiate_class_template.
10790 TMPL is the template to consider and TARGS is the list of arguments of
10791 that template. */
10793 static void
10795 {
10796 location_t saved_location;
10807 {
10819 /* Make access check error messages point to the location
10820 of the use of the typedef. */
10824 tf_warning_or_error);
10825 }
10827 }
10829 static tree
10831 {
10833 tree typedecl;
10834 tree pbinfo;
10835 tree base_list;
10837 tree fn_context;
10846 /* Figure out which template is being instantiated. */
10850 /* Mark the type as in the process of being defined. */
10853 /* We may be in the middle of deferred access check. Disable
10854 it now. */
10857 /* Determine what specialization of the original template to
10858 instantiate. */
10863 {
10864 /* This TYPE is actually an instantiation of a partial
10865 specialization. We replace the innermost set of ARGS with
10866 the arguments appropriate for substitution. For example,
10867 given:
10869 template <class T> struct S {};
10870 template <class T> struct S<T*> {};
10872 and supposing that we are instantiating S<int*>, ARGS will
10873 presently be {int*} -- but we need {int}. */
10876 }
10877 else
10878 {
10881 }
10883 /* If the template we're instantiating is incomplete, then clearly
10884 there's nothing we can do. */
10886 {
10887 /* We can try again later. */
10890 }
10892 /* If we've recursively instantiated too many templates, stop. */
10900 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10905 else
10906 {
10909 }
10910 /* Use #pragma pack from the template context. */
10916 /* Set the input location to the most specialized template definition.
10917 This is needed if tsubsting causes an error. */
10929 {
10932 /* Adjust visibility for template arguments. */
10934 }
10940 /* We should never instantiate a nested class before its enclosing
10941 class; we need to look up the nested class by name before we can
10942 instantiate it, and that lookup should instantiate the enclosing
10943 class. */
10949 {
10950 tree pbase_binfo;
10951 tree pushed_scope;
10954 /* We must enter the scope containing the type, as that is where
10955 the accessibility of types named in dependent bases are
10956 looked up from. */
10959 /* Substitute into each of the bases to determine the actual
10960 basetypes. */
10962 {
10963 tree base;
10969 {
10970 expanded_bases =
10977 }
10980 {
10982 /* Extract the already-expanded base class. */
10984 else
10985 /* Substitute to figure out the base class. */
10987 NULL_TREE);
10995 }
10996 }
10998 /* The list is now in reverse order; correct that. */
11003 }
11004 /* Now call xref_basetypes to set up all the base-class
11005 information. */
11013 /* Now that our base classes are set up, enter the scope of the
11014 class, so that name lookups into base classes, etc. will work
11015 correctly. This is precisely analogous to what we do in
11016 begin_class_definition when defining an ordinary non-template
11017 class, except we also need to push the enclosing classes. */
11020 /* Now members are processed in the order of declaration. */
11023 {
11027 {
11029 {
11031 /* A closure type for a lambda in an NSDMI or default argument.
11032 Ignore it; it will be regenerated when needed. */
11035 /* Build new CLASSTYPE_NESTED_UTDS. */
11037 tree newtag;
11043 /* If the member is a class template, then -- even after
11044 substitution -- there may be dependent types in the
11045 template argument list for the class. We increment
11046 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11047 that function will assume that no types are dependent
11048 when outside of a template. */
11058 {
11062 /* Unfortunately, lookup_template_class sets
11063 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11064 instantiation (i.e., for the type of a member
11065 template class nested within a template class.)
11066 This behavior is required for
11067 maybe_process_partial_specialization to work
11068 correctly, but is not accurate in this case;
11069 the TAG is not an instantiation of anything.
11070 (The corresponding TEMPLATE_DECL is an
11071 instantiation, but the TYPE is not.) */
11074 /* Now, we call pushtag to put this NEWTAG into the scope of
11075 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
11076 pushtag calling push_template_decl. We don't have to do
11077 this for enums because it will already have been done in
11078 tsubst_enum. */
11082 }
11083 }
11085 {
11086 tree r;
11095 /* Instantiate members marked with attribute used. */
11101 }
11104 /* A closure type for a lambda in an NSDMI or default argument.
11106 else
11107 {
11108 /* Build new TYPE_FIELDS. */
11110 {
11111 tree condition;
11114 condition =
11124 }
11126 {
11127 tree r;
11131 /* The file and line for this declaration, to
11132 assist in error message reporting. Since we
11133 called push_tinst_level above, we don't need to
11134 restore these. */
11144 {
11145 /* A capture pack became multiple fields. */
11148 }
11151 {
11155 {
11156 /* In [temp.inst]:
11158 [t]he initialization (and any associated
11159 side-effects) of a static data member does
11160 not occur unless the static data member is
11161 itself used in a way that requires the
11162 definition of the static data member to
11163 exist.
11165 Therefore, we do not substitute into the
11166 initialized for the static data member here. */
11167 finish_static_data_member_decl
11173 /* Instantiate members marked with attribute used. */
11176 }
11178 {
11179 /* Determine whether R has a valid type and can be
11180 completed later. If R is invalid, then its type
11181 is replaced by error_mark_node. */
11187 {
11188 /* If R's type couldn't be completed and
11189 it isn't a flexible array member (whose
11190 type is incomplete by definition) give
11191 an error. */
11194 }
11199 {
11202 }
11203 }
11205 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
11206 such a thing will already have been added to the field
11207 list by tsubst_enum in finish_member_declaration in the
11208 CLASSTYPE_NESTED_UTDS case above. */
11212 {
11215 }
11216 }
11217 }
11218 }
11219 }
11220 else
11221 {
11224 {
11225 /* Build new CLASSTYPE_FRIEND_CLASSES. */
11231 {
11232 /* template <class T> friend class C; */
11235 }
11237 {
11238 /* template <class T> friend class C::D; */
11244 }
11247 {
11248 /* This could be either
11250 friend class T::C;
11252 when dependent_type_p is false or
11254 template <class U> friend class T::C;
11256 otherwise. */
11257 /* Bump processing_template_decl in case this is something like
11258 template <class T> friend struct A<T>::B. */
11265 }
11269 {
11270 /* friend class C;
11272 where C hasn't been declared yet. Let's lookup name
11273 from namespace scope directly, bypassing any name that
11274 come from dependent base class. */
11277 /* The call to xref_tag_from_type does injection for friend
11278 classes. */
11280 friend_type =
11284 }
11286 /* friend class C<T>; */
11289 /* Otherwise it's
11291 friend class C;
11293 where C is already declared or
11295 friend class C<int>;
11297 We don't have to do anything in these cases. */
11300 /* Trick make_friend_class into realizing that the friend
11301 we're adding is a template, not an ordinary class. It's
11302 important that we use make_friend_class since it will
11303 perform some error-checking and output cross-reference
11304 information. */
11312 }
11313 else
11314 {
11315 /* Build new DECL_FRIENDLIST. */
11316 tree r;
11318 /* The file and line for this declaration, to
11319 assist in error message reporting. Since we
11320 called push_tinst_level above, we don't need to
11321 restore these. */
11325 {
11328 }
11333 {
11336 }
11337 }
11338 }
11339 }
11342 {
11343 /* Restore these before substituting into the lambda capture
11344 initializers. */
11347 }
11349 /* Set the file and line number information to whatever is given for
11350 the class itself. This puts error messages involving generated
11351 implicit functions at a predictable point, and the same point
11352 that would be used for non-template classes. */
11359 /* We don't instantiate default arguments for member functions. 14.7.1:
11361 The implicit instantiation of a class template specialization causes
11362 the implicit instantiation of the declarations, but not of the
11363 definitions or default arguments, of the class member functions,
11364 member classes, static data members and member templates.... */
11366 /* Some typedefs referenced from within the template code need to be access
11367 checked at template instantiation time, i.e now. These types were
11368 added to the template at parsing time. Let's get those and perform
11369 the access checks then. */
11378 /* The vtable for a template class can be emitted in any translation
11379 unit in which the class is instantiated. When there is no key
11380 method, however, finish_struct_1 will already have added TYPE to
11381 the keyed_classes. */
11386 }
11388 /* Wrapper for instantiate_class_template_1. */
11390 tree
11392 {
11393 tree ret;
11398 }
11400 static tree
11402 {
11403 tree r;
11409 else
11410 {
11417 }
11419 }
11421 /* Given a function parameter pack TMPL_PARM and some function parameters
11422 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11423 and set *SPEC_P to point at the next point in the list. */
11425 tree
11427 {
11428 /* Collect all of the extra "packed" parameters into an
11429 argument pack. */
11430 tree parmvec;
11440 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11444 {
11449 }
11451 /* Build the argument packs. */
11456 }
11458 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11459 NONTYPE_ARGUMENT_PACK. */
11461 static tree
11463 {
11465 }
11467 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11468 pack expansion with no extra args, 2 if it has extra args, or 0
11469 if it is not a pack expansion. */
11471 static int
11473 {
11479 /* A decl pack is itself an expansion. */
11486 }
11489 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11491 static tree
11493 {
11500 }
11502 /* This is a subroutine of tsubst_pack_expansion.
11504 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11505 mechanism to store the (non complete list of) arguments of the
11506 substitution and return a non substituted pack expansion, in order
11507 to wait for when we have enough arguments to really perform the
11508 substitution. */
11510 static bool
11514 {
11515 /* If one pack has an expansion and another pack has a normal
11516 argument or if one pack has an empty argument and an another
11517 one hasn't then tsubst_pack_expansion cannot perform the
11518 substitution and need to fall back on the
11519 PACK_EXPANSION_EXTRA mechanism. */
11527 {
11530 parm_pack;
11532 {
11537 /* We can't substitute a pack expansion with extra args into
11538 our pattern. */
11542 else
11544 }
11548 }
11550 }
11552 /* [temp.variadic]/6 says that:
11554 The instantiation of a pack expansion [...]
11555 produces a list E1,E2, ..., En, where N is the number of elements
11556 in the pack expansion parameters.
11558 This subroutine of tsubst_pack_expansion produces one of these Ei.
11560 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11561 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11562 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11563 INDEX is the index 'i' of the element Ei to produce. ARGS,
11564 COMPLAIN, and IN_DECL are the same parameters as for the
11565 tsubst_pack_expansion function.
11567 The function returns the resulting Ei upon successful completion,
11568 or error_mark_node.
11570 Note that this function possibly modifies the ARGS parameter, so
11571 it's the responsibility of the caller to restore it. */
11573 static tree
11575 tree parm_packs,
11577 tree args /* This parm gets
11579 tsubst_flags_t complain,
11580 tree in_decl)
11581 {
11582 tree t;
11585 /* For each parameter pack, change the substitution of the parameter
11586 pack to the ith argument in its argument pack, then expand the
11587 pattern. */
11589 {
11594 ith_elem_is_expansion |=
11597 /* Select the Ith argument from the pack. */
11601 {
11603 {
11608 }
11609 else
11611 }
11612 else
11613 {
11618 {
11620 /* Update the corresponding argument. */
11622 }
11623 else
11624 /* Re-use the ARGUMENT_PACK_SELECT. */
11626 }
11628 }
11630 /* Substitute into the PATTERN with the (possibly altered)
11631 arguments. */
11633 /* Expanding a fixed parameter pack from
11634 coerce_template_parameter_pack. */
11639 {
11642 else
11645 }
11649 else
11652 /* If the Ith argument pack element is a pack expansion, then
11653 the Ith element resulting from the substituting is going to
11654 be a pack expansion as well. */
11659 }
11661 /* When the unexpanded parameter pack in a fold expression expands to an empty
11662 sequence, the value of the expression is as follows; the program is
11663 ill-formed if the operator is not listed in this table.
11665 && true
11666 || false
11667 , void() */
11669 tree
11671 {
11675 {
11684 }
11690 }
11692 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11693 form an expression that combines the two terms using the
11694 operator of T. */
11696 static tree
11698 {
11702 // Handle compound assignment operators.
11707 {
11717 complain);
11718 }
11719 }
11721 /* Substitute ARGS into the pack of a fold expression T. */
11725 {
11727 }
11729 /* Substitute ARGS into the pack of a fold expression T. */
11733 {
11735 }
11737 /* Expand a PACK of arguments into a grouped as left fold.
11738 Given a pack containing elements A0, A1, ..., An and an
11739 operator @, this builds the expression:
11741 ((A0 @ A1) @ A2) ... @ An
11743 Note that PACK must not be empty.
11745 The operator is defined by the original fold expression T. */
11747 static tree
11749 {
11752 {
11755 }
11757 }
11759 /* Substitute into a unary left fold expression. */
11761 static tree
11763 tree in_decl)
11764 {
11769 {
11773 }
11776 else
11778 }
11780 /* Substitute into a binary left fold expression.
11782 Do ths by building a single (non-empty) vector of argumnts and
11783 building the expression from those elements. */
11785 static tree
11787 tree in_decl)
11788 {
11797 {
11802 }
11810 }
11812 /* Expand a PACK of arguments into a grouped as right fold.
11813 Given a pack containing elementns A0, A1, ..., and an
11814 operator @, this builds the expression:
11816 A0@ ... (An-2 @ (An-1 @ An))
11818 Note that PACK must not be empty.
11820 The operator is defined by the original fold expression T. */
11822 tree
11824 {
11825 // Build the expression.
11829 {
11832 }
11834 }
11836 /* Substitute into a unary right fold expression. */
11838 static tree
11840 tree in_decl)
11841 {
11846 {
11850 }
11853 else
11855 }
11857 /* Substitute into a binary right fold expression.
11859 Do ths by building a single (non-empty) vector of arguments and
11860 building the expression from those elements. */
11862 static tree
11864 tree in_decl)
11865 {
11874 {
11879 }
11888 }
11890 /* Walk through the pattern of a pack expansion, adding everything in
11891 local_specializations to a list. */
11893 struct el_data
11894 {
11896 tree extra;
11897 tsubst_flags_t complain;
11901 };
11902 static tree
11904 {
11910 /* Remember local typedefs (85214). */
11916 {
11918 /* Don't mess with variables declared within the pattern. */
11921 {
11922 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11925 {
11931 }
11933 {
11934 /* Handle lambda capture here, since we aren't doing any
11935 substitution now, and so tsubst_copy won't call
11936 process_outer_var_ref. */
11940 {
11946 {
11947 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11948 proxies. */
11950 {
11955 }
11957 }
11958 }
11959 }
11960 }
11964 }
11966 }
11967 static tree
11969 {
11973 }
11975 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
11976 for use in PACK_EXPANSION_EXTRA_ARGS. */
11978 tree
11980 {
11986 }
11988 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
11989 normal template args to ARGS. */
11991 tree
11993 {
11995 {
11997 {
11998 /* The partial instantiation involved local declarations collected in
11999 extract_local_specs; map from the general template to our local
12000 context. */
12006 /* else inst is already a full instantiation of the pack. */
12008 }
12011 }
12013 }
12015 /* Substitute ARGS into T, which is an pack expansion
12016 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12017 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12018 (if only a partial substitution could be performed) or
12019 ERROR_MARK_NODE if there was an error. */
12020 tree
12022 tree in_decl)
12023 {
12024 tree pattern;
12029 tree result;
12037 /* Add in any args remembered from an earlier partial instantiation. */
12042 /* Determine the argument packs that will instantiate the parameter
12043 packs used in the expansion expression. While we're at it,
12044 compute the number of arguments to be expanded and make sure it
12045 is consistent. */
12048 {
12055 {
12061 complain);
12062 else
12066 }
12068 {
12070 {
12073 parm_pack);
12075 }
12078 }
12080 {
12081 /* We know we have correct local_specializations if this
12082 expansion is at function scope, or if we're dealing with a
12083 local parameter in a requires expression; for the latter,
12084 tsubst_requires_expr set it up appropriately. */
12087 else
12088 /* We can't rely on local_specializations for a parameter
12089 name used later in a function declaration (such as in a
12090 late-specified return type). Even if it exists, it might
12091 have the wrong value for a recursive call. */
12095 {
12096 /* This parameter pack was used in an unevaluated context. Just
12097 make a dummy decl, since it's only used for its type. */
12102 /* Partial instantiation of the parm_pack, we can't build
12103 up an argument pack yet. */
12105 else
12107 }
12109 /* This argument pack isn't fully instantiated yet. We set this
12110 flag rather than clear arg_pack because we do want to do the
12111 optimization below, and we don't want to substitute directly
12112 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
12113 where it isn't expected). */
12115 }
12117 {
12121 }
12122 else
12123 {
12129 }
12136 /* This can only happen if we forget to expand an argument
12137 pack somewhere else. Just return an error, silently. */
12138 {
12142 }
12145 {
12149 /* Don't bother trying to do a partial substitution with
12150 incomplete packs; we'll try again after deduction. */
12158 {
12163 pattern);
12164 else
12166 pattern);
12168 }
12170 /* Keep track of the parameter packs and their corresponding
12171 argument packs. */
12174 }
12175 else
12176 {
12177 /* We can't substitute for this parameter pack. We use a flag as
12178 well as the missing_level counter because function parameter
12179 packs don't have a level. */
12182 }
12183 }
12185 /* If the expansion is just T..., return the matching argument pack, unless
12186 we need to call convert_from_reference on all the elements. This is an
12187 important optimization; see c++/68422. */
12190 {
12193 /* If the argument pack is a single pack expansion, pull it out. */
12198 /* Types need no adjustment, nor does sizeof..., and if we still have
12199 some pack expansion args we won't do anything yet. */
12204 /* Also optimize expression pack expansions if we can tell that the
12205 elements won't have reference type. */
12211 /* Otherwise use the normal path so we get convert_from_reference. */
12212 }
12214 /* We cannot expand this expansion expression, because we don't have
12215 all of the argument packs we need. */
12217 {
12218 /* We got some full packs, but we can't substitute them in until we
12219 have values for all the packs. So remember these until then. */
12225 }
12227 {
12228 /* There were no real arguments, we're just replacing a parameter
12229 pack with another version of itself. Substitute into the
12230 pattern and return a PACK_EXPANSION_*. The caller will need to
12231 deal with that. */
12235 else
12239 }
12244 {
12245 /* We're in a late-specified return type, so create our own local
12246 specializations map; the current map is either NULL or (in the
12247 case of recursive unification) might have bindings that we don't
12248 want to use or alter. */
12251 }
12253 /* For each argument in each argument pack, substitute into the
12254 pattern. */
12258 {
12260 i,
12262 in_decl);
12265 {
12268 }
12269 }
12271 /* Update ARGS to restore the substitution from parameter packs to
12272 their argument packs. */
12274 {
12281 else
12282 {
12290 /* Update the corresponding argument. */
12294 else
12296 }
12297 }
12300 {
12303 }
12305 /* If the dependent pack arguments were such that we end up with only a
12306 single pack expansion again, there's no need to keep it in a TREE_VEC. */
12312 }
12314 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
12315 TMPL. We do this using DECL_PARM_INDEX, which should work even with
12316 parameter packs; all parms generated from a function parameter pack will
12317 have the same DECL_PARM_INDEX. */
12319 tree
12321 {
12323 tree patparm;
12326 {
12332 }
12333 else
12334 {
12339 }
12342 }
12344 /* Make an argument pack out of the TREE_VEC VEC. */
12346 static tree
12348 {
12349 tree pack;
12353 else
12354 {
12357 }
12360 }
12362 /* Return an exact copy of template args T that can be modified
12363 independently. */
12365 static tree
12367 {
12375 {
12380 }
12386 }
12388 /* Substitute ARGS into the vector or list of template arguments T. */
12390 static tree
12392 {
12404 {
12406 tree new_arg;
12411 {
12412 /* Substitute into an expansion expression. */
12416 /* Add to the expanded length adjustment the number of
12417 expanded arguments. We subtract one from this
12418 measurement, because the argument pack expression
12419 itself is already counted as 1 in
12420 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12421 the argument pack is empty. */
12423 }
12425 {
12426 /* Substitute into each of the arguments. */
12435 else
12440 }
12441 else
12450 }
12455 /* Make space for the expanded arguments coming from template
12456 argument packs. */
12458 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12459 arguments for a member template.
12460 In that case each TREE_VEC in ORIG_T represents a level of template
12461 arguments, and ORIG_T won't carry any non defaulted argument count.
12462 It will rather be the nested TREE_VECs that will carry one.
12463 In other words, ORIG_T carries a non defaulted argument count only
12464 if it doesn't contain any nested TREE_VEC. */
12466 {
12470 }
12472 {
12476 {
12479 /* Now expand the template argument pack "in place". */
12482 }
12483 else
12484 {
12486 out++;
12487 }
12488 }
12491 }
12493 /* Substitute ARGS into one level PARMS of template parameters. */
12495 static tree
12497 {
12504 {
12512 }
12515 }
12517 /* Return the result of substituting ARGS into the template parameters
12518 given by PARMS. If there are m levels of ARGS and m + n levels of
12519 PARMS, then the result will contain n levels of PARMS. For
12520 example, if PARMS is `template <class T> template <class U>
12521 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12522 result will be `template <int*, double, class V>'. */
12524 static tree
12526 {
12530 /* When substituting into a template, we must set
12531 PROCESSING_TEMPLATE_DECL as the template parameters may be
12532 dependent if they are based on one-another, and the dependency
12533 predicates are short-circuit outside of templates. */
12540 {
12547 }
12552 }
12554 /* Return the result of substituting ARGS into one template parameter
12555 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12556 parameter and which TREE_PURPOSE is the default argument of the
12557 template parameter. */
12559 static tree
12561 {
12582 }
12584 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12585 type T. If T is not an aggregate or enumeration type, it is
12586 handled as if by tsubst. IN_DECL is as for tsubst. If
12587 ENTERING_SCOPE is nonzero, T is the context for a template which
12588 we are presently tsubst'ing. Return the substituted value. */
12590 static tree
12592 tree args,
12593 tsubst_flags_t complain,
12594 tree in_decl,
12596 {
12601 {
12606 /* Fall through. */
12610 {
12611 tree argvec;
12612 tree context;
12613 tree r;
12617 /* In "sizeof(X<I>)" we need to evaluate "I". */
12623 /* First, determine the context for the type we are looking
12624 up. */
12627 {
12630 /* If context is a nested class inside a class template,
12631 it may still need to be instantiated (c++/33959). */
12633 }
12635 /* Then, figure out what arguments are appropriate for the
12636 type we are trying to find. For example, given:
12638 template <class T> struct S;
12639 template <class T, class U> void f(T, U) { S<U> su; }
12641 and supposing that we are instantiating f<int, double>,
12642 then our ARGS will be {int, double}, but, when looking up
12643 S we only want {double}. */
12648 else
12649 {
12653 }
12659 }
12660 else
12661 /* This is not a template type, so there's nothing to do. */
12666 }
12667 }
12671 /* Substitute into the default argument ARG (a default argument for
12672 FN), which has the indicated TYPE. */
12674 tree
12676 tsubst_flags_t complain)
12677 {
12682 /* This can happen in invalid code. */
12700 /* This default argument came from a template. Instantiate the
12701 default argument here, not in tsubst. In the case of
12702 something like:
12704 template <class T>
12705 struct S {
12706 static T t();
12707 void f(T = t());
12708 };
12710 we must be careful to do name lookup in the scope of S<T>,
12711 rather than in the current class. */
12713 /* The "this" pointer is not valid in a default argument. */
12715 {
12720 }
12725 /* The default argument expression may cause implicitly defined
12726 member functions to be synthesized, which will result in garbage
12727 collection. We must treat this situation as if we were within
12728 the body of function so as to avoid collecting live data on the
12729 stack. */
12739 /* Restore the "this" pointer. */
12741 {
12744 }
12751 /* Make sure the default argument is reasonable. */
12757 {
12761 }
12764 }
12766 /* Substitute into all the default arguments for FN. */
12768 static void
12770 {
12771 tree arg;
12772 tree tmpl_args;
12776 /* If this function is not yet instantiated, we certainly don't need
12777 its default arguments. */
12780 /* Don't do this again for clones. */
12786 arg;
12792 complain);
12793 }
12795 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12797 static tree
12799 tree lambda_fntype)
12800 {
12805 /* Nobody should be tsubst'ing into non-template functions. */
12809 {
12810 /* If T is not dependent, just return it. */
12814 /* Calculate the most general template of which R is a
12815 specialization. */
12818 /* We're substituting a lambda function under tsubst_lambda_expr but not
12819 directly from it; find the matching function we're already inside.
12820 But don't do this if T is a generic lambda with a single level of
12821 template parms, as in that case we're doing a normal instantiation. */
12827 /* Calculate the complete set of arguments used to
12828 specialize R. */
12830 (DECL_TEMPLATE_RESULT
12836 /* Check to see if we already have this specialization. */
12838 {
12842 }
12844 /* We can see more levels of arguments than parameters if
12845 there was a specialization of a member template, like
12846 this:
12848 template <class T> struct S { template <class U> void f(); }
12849 template <> template <class U> void S<int>::f(U);
12851 Here, we'll be substituting into the specialization,
12852 because that's where we can find the code we actually
12853 want to generate, but we'll have enough arguments for
12854 the most general template.
12856 We also deal with the peculiar case:
12858 template <class T> struct S {
12859 template <class U> friend void f();
12860 };
12861 template <class U> void f() {}
12862 template S<int>;
12863 template void f<double>();
12865 Here, the ARGS for the instantiation of will be {int,
12866 double}. But, we only need as many ARGS as there are
12867 levels of template parameters in CODE_PATTERN. We are
12868 careful not to get fooled into reducing the ARGS in
12869 situations like:
12871 template <class T> struct S { template <class U> void f(U); }
12872 template <class T> template <> void S<T>::f(int) {}
12874 which we can spot because the pattern will be a
12875 specialization in this case. */
12882 }
12883 else
12884 {
12885 /* This special case arises when we have something like this:
12887 template <class T> struct S {
12888 friend void f<int>(int, double);
12889 };
12891 Here, the DECL_TI_TEMPLATE for the friend declaration
12892 will be an IDENTIFIER_NODE. We are being called from
12893 tsubst_friend_function, and we want only to create a
12894 new decl (R) with appropriate types so that we can call
12895 determine_specialization. */
12898 }
12915 /* If we hit excessive deduction depth, the type is bogus even if
12916 it isn't error_mark_node, so don't build a decl. */
12920 /* We do NOT check for matching decls pushed separately at this
12921 point, as they may not represent instantiations of this
12922 template, and in any case are considered separate under the
12923 discrete model. */
12927 /* Clear out the mangled name and RTL for the instantiation. */
12930 /* Leave DECL_INITIAL set on deleted instantiations. */
12935 /* OpenMP UDRs have the only argument a reference to the declared
12936 type. We want to diagnose if the declared type is a reference,
12937 which is invalid, but as references to references are usually
12938 quietly merged, diagnose it here. */
12940 {
12941 tree argtype
12946 "reference type %qT in "
12950 argtype);
12951 }
12954 /* Type-conversion operator. Reconstruct the name, in
12955 case it's the name of one of the template's parameters. */
12965 {
12969 }
12976 /* If this is an instantiation of a function with internal
12977 linkage, we already know what object file linkage will be
12978 assigned to the instantiation. */
12987 /* We'll re-clone as appropriate in instantiate_template. */
12990 /* If we aren't complaining now, return on error before we register
12991 the specialization so that we'll complain eventually. */
12997 /* When instantiating a constrained member, substitute
12998 into the constraints to create a new constraint. */
13001 {
13004 }
13006 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
13007 this in the special friend case mentioned above where
13008 GEN_TMPL is NULL. */
13010 {
13015 tree new_r
13018 /* We instantiated this while substituting into
13019 the type earlier (template/friend54.C). */
13022 /* We're not supposed to instantiate default arguments
13023 until they are called, for a template. But, for a
13024 declaration like:
13026 template <class T> void f ()
13027 { extern void g(int i = T()); }
13029 we should do the substitution when the template is
13030 instantiated. We handle the member function case in
13031 instantiate_class_template since the default arguments
13032 might refer to other members of the class. */
13037 }
13038 else
13041 /* Copy the list of befriending classes. */
13045 {
13049 }
13052 {
13056 /* If this is an instantiation of a member template, clone it.
13057 If it isn't, that'll be handled by
13058 clone_constructors_and_destructors. */
13061 }
13072 /* Possibly limit visibility based on template args. */
13075 {
13079 }
13088 }
13090 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
13092 static tree
13094 tree lambda_fntype)
13095 {
13096 /* We can get here when processing a member function template,
13097 member class template, or template template parameter. */
13100 tree spec;
13101 tree tmpl_args;
13102 tree full_args;
13103 tree r;
13107 {
13108 /* Template template parameter is treated here. */
13112 /* If we get a real template back, return it. This can happen in
13113 the context of most_specialized_partial_spec. */
13116 else
13117 /* The new TEMPLATE_DECL was built in
13118 reduce_template_parm_level. */
13121 }
13124 {
13125 /* We might already have an instance of this template.
13126 The ARGS are for the surrounding class type, so the
13127 full args contain the tsubst'd args for the context,
13128 plus the innermost args from the template decl. */
13132 /* Because this is a template, the arguments will still be
13133 dependent, even after substitution. If
13134 PROCESSING_TEMPLATE_DECL is not set, the dependency
13135 predicates will short-circuit. */
13143 /* If this is a default template template argument,
13144 tsubst might not have changed anything. */
13152 }
13154 /* Make a new template decl. It will be similar to the
13155 original, but will record the current template arguments.
13156 We also create a new function declaration, which is just
13157 like the old one, but points to this new template, rather
13158 than the old one. */
13163 // Build new template info linking to the original template decl.
13165 {
13168 }
13169 else
13172 /* The template parameters for this new template are all the
13173 template parameters for the old template, except the
13174 outermost level of parameters. */
13177 complain);
13181 {
13182 tree new_type;
13190 /* For a partial specialization, we need to keep pointing to
13191 the primary template. */
13197 }
13198 else
13199 {
13200 tree new_decl;
13204 else
13214 {
13217 }
13218 else
13219 {
13222 }
13223 }
13233 /* Record this non-type partial instantiation. */
13239 }
13241 /* True if FN is the op() for a lambda in an uninstantiated template. */
13243 bool
13245 {
13250 }
13252 /* We're instantiating a variable from template function TCTX. Return the
13253 corresponding current enclosing scope. This gets complicated because lambda
13254 functions in templates are regenerated rather than instantiated, but generic
13255 lambda functions are subsequently instantiated. */
13257 static tree
13259 {
13268 {
13281 }
13283 }
13285 /* Substitute the ARGS into the T, which is a _DECL. Return the
13286 result of the substitution. Issue error and warning messages under
13287 control of COMPLAIN. */
13289 static tree
13291 {
13292 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13293 location_t saved_loc;
13298 /* Set the filename and linenumber to improve error-reporting. */
13303 {
13313 {
13321 {
13322 /* If there is a local specialization that isn't a
13323 parameter pack, it means that we're doing a "simple"
13324 substitution from inside tsubst_pack_expansion. Just
13325 return the local specialization (which will be a single
13326 parm). */
13333 /* Expand the TYPE_PACK_EXPANSION that provides the types for
13334 the parameters in this function parameter pack. */
13338 {
13341 /* Zero-length parameter packs are boring. Just substitute
13342 into the chain. */
13346 }
13347 else
13348 {
13349 /* All we did was update the type. Make a note of that. */
13352 }
13353 }
13355 /* Loop through all of the parameters we'll build. When T is
13356 a function parameter pack, LEN is the number of expanded
13357 types in EXPANDED_TYPES; otherwise, LEN is 1. */
13360 {
13367 /* We're on the Ith parameter of the function parameter
13368 pack. */
13369 {
13370 /* Get the Ith type. */
13373 /* Rename the parameter to include the index. */
13376 }
13378 /* We're dealing with a normal parameter. */
13386 {
13389 else
13392 }
13402 /* Keep track of the first new parameter we
13403 generate. That's what will be returned to the
13404 caller. */
13408 /* Build a proper chain of parameters when substituting
13409 into a function parameter pack. */
13412 }
13414 /* If cp_unevaluated_operand is set, we're just looking for a
13415 single dummy parameter, so don't keep going. */
13420 /* FIRST_R contains the start of the chain we've built. */
13422 }
13426 {
13433 {
13434 /* This field is a lambda capture pack. Return a TREE_VEC of
13435 the expanded fields to instantiate_class_template_1. */
13439 {
13442 }
13443 else
13444 {
13445 /* All we did was update the type. Make a note of that. */
13448 }
13449 }
13452 {
13455 {
13459 }
13469 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13470 number of bits. */
13476 {
13477 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13478 NSDMI in perform_member_init. Still set DECL_INITIAL
13479 so that we know there is one. */
13484 }
13485 /* We don't have to set DECL_CONTEXT here; it is set by
13486 finish_member_declaration. */
13494 }
13498 }
13502 /* We reach here only for member using decls. We also need to check
13503 uses_template_parms because DECL_DEPENDENT_P is not set for a
13504 using-declaration that designates a member of the current
13505 instantiation (c++/53549). */
13508 {
13512 {
13517 {
13521 {
13524 }
13525 else
13526 {
13529 }
13531 }
13532 }
13533 else
13534 {
13540 else
13541 {
13544 }
13545 }
13546 }
13547 else
13548 {
13551 }
13556 {
13559 tree spec;
13561 tree ctx;
13570 {
13571 /* If this is the canonical decl, we don't have to
13572 mess with instantiations, and often we can't (for
13573 typename, template type parms and such). Note that
13574 TYPE_NAME is not correct for the above test if
13575 we've copied the type for a typedef. */
13581 }
13583 /* Check to see if we already have the specialization we
13584 need. */
13587 {
13588 /* T is a static data member or namespace-scope entity.
13589 We have to substitute into namespace-scope variables
13590 (not just variable templates) because of cases like:
13592 template <class T> void f() { extern T t; }
13594 where the entity referenced is not known until
13595 instantiation time. */
13599 {
13601 complain,
13603 /* If CTX is unchanged, then T is in fact the
13604 specialization we want. That situation occurs when
13605 referencing a static data member within in its own
13606 class. We can use pointer equality, rather than
13607 same_type_p, because DECL_CONTEXT is always
13608 canonical... */
13610 /* ... unless T is a member template; in which
13611 case our caller can be willing to create a
13612 specialization of that template represented
13613 by T. */
13617 }
13620 {
13625 argvec = (coerce_innermost_template_parms
13633 }
13634 }
13635 else
13636 {
13637 /* A local variable. */
13639 /* Subsequent calls to pushdecl will fill this in. */
13641 /* Unless this is a reference to a static variable from an
13642 enclosing function, in which case we need to fill it in now. */
13644 {
13648 }
13650 }
13651 /* If we already have the specialization we need, there is
13652 nothing more to do. */
13654 {
13657 }
13659 /* Create a new node for the specialization we need. */
13662 {
13665 else
13673 {
13674 /* Mask off any template args past the variable's context so we
13675 don't replace the auto with an unrelated argument. */
13679 /* This should never happen with the new lambda instantiation
13680 model, but keep the handling just in case. */
13683 }
13685 }
13687 {
13693 {
13694 /* It may seem that this case cannot occur, since:
13696 typedef void f();
13697 void g() { f x; }
13699 declares a function, not a variable. However:
13701 typedef void f();
13702 template <typename T> void g() { T t; }
13703 template void g<f>();
13705 is an attempt to declare a variable with function
13706 type. */
13708 /* R is not yet sufficiently initialized, so we
13709 just use its name. */
13712 }
13714 /* Wait until cp_finish_decl to set this again, to handle
13715 circular dependency (template/instantiate6.C). */
13720 {
13725 {
13728 }
13730 }
13734 }
13740 /* Clear out the mangled name and RTL for the instantiation. */
13744 /* The initializer must not be expanded until it is required;
13745 see [temp.inst]. */
13749 {
13755 /* Possibly limit visibility based on template args. */
13758 {
13762 }
13764 }
13767 {
13768 /* A static data member declaration is always marked
13769 external when it is declared in-class, even if an
13770 initializer is present. We mimic the non-template
13771 processing here. */
13779 }
13780 else
13781 {
13786 }
13794 /* Preserve a typedef that names a type. */
13796 {
13800 /* An alias template specialization can be dependent
13801 even if its underlying type is not. */
13803 }
13806 }
13811 }
13812 #undef RETURN
13814 out:
13815 /* Restore the file and line information. */
13819 }
13821 /* Substitute into the ARG_TYPES of a function type.
13822 If END is a TREE_CHAIN, leave it and any following types
13823 un-substituted. */
13825 static tree
13827 tree args,
13828 tree end,
13829 tsubst_flags_t complain,
13830 tree in_decl)
13831 {
13832 tree remaining_arg_types;
13836 tree default_arg;
13847 {
13848 /* For a pack expansion, perform substitution on the
13849 entire expression. Later on, we'll handle the arguments
13850 one-by-one. */
13855 /* So that we'll spin through the parameters, one by one. */
13857 else
13858 {
13859 /* We only partially substituted into the parameter
13860 pack. Our type is TYPE_PACK_EXPANSION. */
13863 }
13864 }
13877 {
13879 {
13883 }
13885 }
13886 /* DR 657. */
13890 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13891 top-level qualifiers as required. */
13894 /* We do not substitute into default arguments here. The standard
13895 mandates that they be instantiated only when needed, which is
13896 done in build_over_call. */
13899 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13900 since the new op() won't have any associated template arguments for us
13901 to refer to later. */
13907 {
13908 /* We've instantiated a template before its default arguments
13909 have been parsed. This can happen for a nested template
13910 class, and is not an error unless we require the default
13911 argument in a call of this function. */
13912 remaining_arg_types =
13915 }
13916 else
13917 remaining_arg_types =
13919 }
13922 }
13924 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13925 *not* handle the exception-specification for FNTYPE, because the
13926 initial substitution of explicitly provided template parameters
13927 during argument deduction forbids substitution into the
13928 exception-specification:
13930 [temp.deduct]
13932 All references in the function type of the function template to the
13933 corresponding template parameters are replaced by the specified tem-
13934 plate argument values. If a substitution in a template parameter or
13935 in the function type of the function template results in an invalid
13936 type, type deduction fails. [Note: The equivalent substitution in
13937 exception specifications is done only when the function is instanti-
13938 ated, at which point a program is ill-formed if the substitution
13939 results in an invalid type.] */
13941 static tree
13943 tree args,
13944 tsubst_flags_t complain,
13945 tree in_decl)
13946 {
13947 tree return_type;
13949 tree fntype;
13951 /* The TYPE_CONTEXT is not used for function/method types. */
13954 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13955 failure. */
13959 {
13960 /* Substitute the argument types. */
13972 {
13973 /* DR 1207: 'this' is in scope in the trailing return type. */
13975 }
13977 /* Substitute the return type. */
13981 {
13984 }
13985 }
13986 else
13987 /* Substitute the return type. */
13992 /* DR 486 clarifies that creation of a function type with an
13993 invalid return type is a deduction failure. */
13996 {
13998 {
14001 else
14003 }
14005 }
14006 /* And DR 657. */
14011 {
14012 /* Substitute the argument types. */
14017 }
14019 /* Construct a new type node and return it. */
14021 {
14024 }
14025 else
14026 {
14028 /* Don't pick up extra function qualifiers from the basetype. */
14031 {
14032 /* [temp.deduct]
14034 Type deduction may fail for any of the following
14035 reasons:
14037 -- Attempting to create "pointer to member of T" when T
14038 is not a class type. */
14041 r);
14043 }
14047 }
14050 /* See comment above. */
14056 }
14058 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
14059 ARGS into that specification, and return the substituted
14060 specification. If there is no specification, return NULL_TREE. */
14062 static tree
14064 tree args,
14065 tsubst_flags_t complain,
14066 tree in_decl,
14068 {
14069 tree specs;
14070 tree new_specs;
14075 {
14076 /* A noexcept-specifier. */
14081 {
14082 /* Defer instantiation of noexcept-specifiers to avoid
14083 excessive instantiations (c++/49107). */
14086 {
14087 /* We already partially instantiated this member template,
14088 so combine the new args with the old. */
14093 }
14094 else
14095 {
14098 }
14099 }
14100 else
14101 new_specs = tsubst_copy_and_build
14105 }
14107 {
14110 else
14112 {
14113 tree spec;
14118 {
14119 /* Expand the pack expansion type. */
14122 in_decl);
14128 else
14129 {
14130 /* We're substituting into a member template, so
14131 we got a TYPE_PACK_EXPANSION back. Add that
14132 expansion and move on. */
14136 expanded_specs,
14137 complain);
14140 }
14141 }
14144 {
14147 else
14152 complain);
14153 }
14156 }
14157 }
14159 }
14161 /* Take the tree structure T and replace template parameters used
14162 therein with the argument vector ARGS. IN_DECL is an associated
14163 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
14164 Issue error and warning messages under control of COMPLAIN. Note
14165 that we must be relatively non-tolerant of extensions here, in
14166 order to preserve conformance; if we allow substitutions that
14167 should not be allowed, we may allow argument deductions that should
14168 not succeed, and therefore report ambiguous overload situations
14169 where there are none. In theory, we could allow the substitution,
14170 but indicate that it should have failed, and allow our caller to
14171 make sure that the right thing happens, but we don't try to do this
14172 yet.
14174 This function is used for dealing with types, decls and the like;
14175 for expressions, use tsubst_expr or tsubst_copy. */
14177 tree
14179 {
14202 else
14207 /* Reuse typedefs. We need to do this to handle dependent attributes,
14208 such as attribute aligned. */
14211 {
14215 {
14216 /* DECL represents an alias template and we want to
14217 instantiate it. */
14221 }
14225 {
14229 }
14234 else
14235 /* The typedef is from a non-template context. */
14239 {
14241 r = cp_build_qualified_type_real
14245 }
14246 else
14247 {
14248 /* We don't have an instantiation yet, so drop the typedef. */
14253 }
14254 }
14271 {
14297 {
14303 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
14304 needed. */
14310 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
14311 with TREE_SIDE_EFFECTS that indicates this is not an integral
14312 constant expression. */
14315 {
14318 }
14321 }
14327 {
14333 /* Early in template argument deduction substitution, we don't
14334 want to reduce the level of 'auto', or it will be confused
14335 with a normal template parm in subsequent deduction. */
14347 {
14350 /* See through ARGUMENT_PACK_SELECT arguments. */
14353 }
14358 {
14360 /* If ARG is an argument pack, we don't actually want to
14361 perform a substitution here, because substitutions
14362 for argument packs are only done
14363 element-by-element. We can get to this point when
14364 substituting the type of a non-type template
14365 parameter pack, when that type actually contains
14366 template parameter packs from an outer template, e.g.,
14368 template<typename... Types> struct A {
14369 template<Types... Values> struct B { };
14370 }; */
14374 {
14380 return cp_build_qualified_type_real
14382 }
14384 {
14385 /* We are processing a type constructed from a
14386 template template parameter. */
14397 /* Consider this code:
14399 template <template <class> class Template>
14400 struct Internal {
14401 template <class Arg> using Bind = Template<Arg>;
14402 };
14404 template <template <class> class Template, class Arg>
14405 using Instantiate = Template<Arg>; //#0
14407 template <template <class> class Template,
14408 class Argument>
14409 using Bind =
14410 Instantiate<Internal<Template>::template Bind,
14411 Argument>; //#1
14413 When #1 is parsed, the
14414 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14415 parameter `Template' in #0 matches the
14416 UNBOUND_CLASS_TEMPLATE representing the argument
14417 `Internal<Template>::template Bind'; We then want
14418 to assemble the type `Bind<Argument>' that can't
14419 be fully created right now, because
14420 `Internal<Template>' not being complete, the Bind
14421 template cannot be looked up in that context. So
14422 we need to "store" `Bind<Argument>' for later
14423 when the context of Bind becomes complete. Let's
14424 store that in a TYPENAME_TYPE. */
14428 argvec),
14429 typename_type,
14430 complain);
14432 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14433 are resolving nested-types in the signature of a
14434 member function templates. Otherwise ARG is a
14435 TEMPLATE_DECL and is the real template to be
14436 instantiated. */
14444 complain);
14445 return cp_build_qualified_type_real
14447 }
14450 else
14451 /* TEMPLATE_PARM_INDEX. */
14453 }
14456 /* This can happen during the attempted tsubst'ing in
14457 unify. This means that we don't yet have any information
14458 about the template parameter in question. */
14461 /* If we get here, we must have been looking at a parm for a
14462 more deeply nested template. Make a new version of this
14463 template parameter, but with a lower level. */
14465 {
14470 {
14472 r = cp_build_qualified_type_real
14476 }
14483 /* Break infinite recursion when substituting the constraints
14485 else
14486 {
14497 {
14498 /* Propagate constraints on placeholders. */
14503 {
14506 }
14507 }
14510 /* We have reduced the level of the template
14511 template parameter, but not the levels of its
14512 template parameters, so canonical_type_parameter
14513 will not be able to find the canonical template
14514 template parameter for this level. Thus, we
14515 require structural equality checking to compare
14516 TEMPLATE_TEMPLATE_PARMs. */
14520 else
14524 {
14526 /* We might need to substitute into the types of non-type
14527 template parameters. */
14539 }
14540 }
14544 /* OK, now substitute the type of the non-type parameter. We
14545 couldn't do it earlier because it might be an auto parameter,
14546 and we wouldn't need to if we had an argument. */
14555 }
14558 }
14561 {
14569 {
14573 }
14576 {
14580 }
14583 {
14587 }
14593 }
14596 /* We should never be tsubsting a binfo. */
14600 /* A vector of template arguments. */
14606 {
14610 /* [temp.deduct]
14612 Type deduction may fail for any of the following
14613 reasons:
14615 -- Attempting to create a pointer to reference type.
14616 -- Attempting to create a reference to a reference type or
14617 a reference to void.
14619 Core issue 106 says that creating a reference to a reference
14620 during instantiation is no longer a cause for failure. We
14621 only enforce this check in strict C++98 mode. */
14625 {
14628 /* We keep track of the last time we issued this error
14629 message to avoid spewing a ton of messages during a
14630 single bad template instantiation. */
14633 {
14638 else
14641 }
14644 }
14648 {
14650 {
14653 type);
14654 else
14656 type);
14657 }
14659 }
14661 {
14665 }
14667 /* In C++0x, during template argument substitution, when there is an
14668 attempt to create a reference to a reference type, reference
14669 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14671 "If a template-argument for a template-parameter T names a type
14672 that is a reference to a type A, an attempt to create the type
14673 'lvalue reference to cv T' creates the type 'lvalue reference to
14674 A,' while an attempt to create the type type rvalue reference to
14675 cv T' creates the type T"
14676 */
14677 r = cp_build_reference_type
14680 else
14685 /* Will this ever be needed for TYPE_..._TO values? */
14689 }
14691 {
14694 {
14695 /* [temp.deduct]
14697 Type deduction may fail for any of the following
14698 reasons:
14700 -- Attempting to create "pointer to member of T" when T
14701 is not a class type. */
14705 }
14707 {
14711 }
14713 {
14717 }
14720 {
14721 /* The type of the implicit object parameter gets its
14722 cv-qualifiers from the FUNCTION_TYPE. */
14723 tree memptr;
14724 tree method_type
14729 complain);
14730 }
14731 else
14734 complain);
14735 }
14738 {
14739 tree fntype;
14740 tree specs;
14745 /* Substitute the exception specification. */
14753 }
14755 {
14760 /* As an optimization, we avoid regenerating the array type if
14761 it will obviously be the same as T. */
14765 /* These checks should match the ones in create_array_type_for_decl.
14767 [temp.deduct]
14769 The deduction may fail for any of the following reasons:
14771 -- Attempting to create an array with an element type that
14772 is void, a function type, or a reference type, or [DR337]
14773 an abstract class type. */
14779 {
14783 }
14795 {
14798 }
14801 }
14804 {
14816 {
14820 }
14822 {
14823 /* Normally, make_typename_type does not require that the CTX
14824 have complete type in order to allow things like:
14826 template <class T> struct S { typename S<T>::X Y; };
14828 But, such constructs have already been resolved by this
14829 point, so here CTX really should have complete type, unless
14830 it's a partial instantiation. */
14833 {
14837 }
14838 }
14845 {
14848 }
14851 {
14853 {
14857 else
14859 }
14861 {
14865 else
14867 }
14868 }
14870 return cp_build_qualified_type_real
14872 }
14875 {
14887 }
14890 {
14891 tree type;
14907 complain);
14908 }
14911 {
14912 tree type;
14923 {
14925 {
14929 }
14932 }
14943 else
14944 {
14948 /* In a template ~id could be either a complement expression
14949 or an unqualified-id naming a destructor; if instantiating
14950 it produces an expression, it's not an id-expression or
14951 member access. */
14954 }
14959 }
14962 {
14966 }
14970 {
14971 tree r;
14975 else
14983 }
14998 /* We should use one of the expression tsubsts for these codes. */
15004 }
15005 }
15007 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
15008 expression on the left-hand side of the "." or "->" operator. We
15009 only do the lookup if we had a dependent BASELINK. Otherwise we
15010 adjust it onto the instantiated heirarchy. */
15012 static tree
15015 {
15027 {
15034 }
15041 {
15047 /* Treat as-if non-dependent below. */
15052 {
15058 }
15062 }
15063 else
15064 /* We're going to overwrite pieces below, make a duplicate. */
15067 /* If lookup found a single function, mark it as used at this point.
15068 (If lookup found multiple functions the one selected later by
15069 overload resolution will be marked as used at that point.) */
15071 {
15077 /* We might have instantiated an auto function. */
15079 }
15082 {
15083 /* Add back the template arguments, if present. */
15088 /* Update the conversion operator type. */
15090 }
15096 {
15098 qualifying_scope,
15099 object_type);
15101 /* We need to call adjust_result_of_qualified_name_lookup in case the
15102 destructor names a base class, but we unset BASELINK_QUALIFIED_P
15103 so that we still get virtual function binding. */
15105 }
15108 }
15110 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
15111 true if the qualified-id will be a postfix-expression in-and-of
15112 itself; false if more of the postfix-expression follows the
15113 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
15114 of "&". */
15116 static tree
15120 {
15121 tree expr;
15122 tree scope;
15123 tree name;
15125 tree template_args;
15130 /* Figure out what name to look up. */
15133 {
15143 }
15144 else
15145 {
15148 }
15150 /* Substitute into the qualifying scope. When there are no ARGS, we
15151 are just trying to simplify a non-dependent expression. In that
15152 case the qualifying scope may be dependent, and, in any case,
15153 substituting will not help. */
15156 {
15159 }
15160 else
15164 {
15171 }
15174 {
15176 {
15177 /* A BIT_NOT_EXPR is used to represent a destructor. */
15179 {
15183 }
15184 else
15187 }
15188 else
15192 {
15194 {
15198 }
15200 }
15201 }
15204 {
15206 scope);
15207 /* Remember that there was a reference to this entity. */
15210 }
15213 {
15219 }
15222 {
15223 /* We may be repeating a check already done during parsing, but
15224 if it was well-formed and passed then, it will pass again
15225 now, and if it didn't, we wouldn't have got here. The case
15226 we want to catch is when we couldn't tell then, and can now,
15227 namely when templ prior to substitution was an
15228 identifier. */
15234 complain);
15235 else
15237 }
15243 {
15244 expr = (adjust_result_of_qualified_name_lookup
15246 expr = (finish_qualified_id_expr
15250 }
15252 /* Expressions do not generally have reference type. */
15254 /* However, if we're about to form a pointer-to-member, we just
15255 want the referenced member referenced. */
15263 }
15265 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
15266 initializer, DECL is the substituted VAR_DECL. Other arguments are as
15267 for tsubst. */
15269 static tree
15272 {
15279 {
15280 /* If we had an initializer but it
15281 instantiated to nothing,
15282 value-initialize the object. This will
15283 only occur when the initializer was a
15284 pack expansion where the parameter packs
15285 used in that expansion were of length
15286 zero. */
15288 complain);
15293 }
15296 }
15298 /* Like tsubst, but deals with expressions. This function just replaces
15299 template parms; to finish processing the resultant expression, use
15300 tsubst_copy_and_build or tsubst_expr. */
15302 static tree
15304 {
15306 tree r;
15314 {
15319 {
15320 /* We get here for a use of 'this' in an NSDMI. */
15324 /* This can happen for a parameter name used later in a function
15325 declaration (such as in a late-specified return type). Just
15326 make a dummy decl, since it's only used for its type. */
15329 /* Give it the template pattern as its context; its true context
15330 hasn't been instantiated yet and this is good enough for
15331 mangling. */
15333 }
15342 {
15343 tree enum_type;
15344 tree v;
15348 /* There is no need to substitute into namespace-scope
15349 enumerators. */
15352 /* If ARGS is NULL, then T is known to be non-dependent. */
15356 /* Unfortunately, we cannot just call lookup_name here.
15357 Consider:
15359 template <int I> int f() {
15360 enum E { a = I };
15361 struct S { void g() { E e = a; } };
15362 };
15364 When we instantiate f<7>::S::g(), say, lookup_name is not
15365 clever enough to find f<7>::a. */
15366 enum_type
15376 /* We didn't find the name. That should never happen; if
15377 name-lookup found it during preliminary parsing, we
15378 should find it again here during instantiation. */
15380 }
15385 {
15386 tree ctx;
15391 {
15394 {
15398 }
15400 }
15401 }
15411 {
15414 {
15415 /* First try name lookup to find the instantiation. */
15418 {
15419 /* Make sure that the one we found is the one we want. */
15423 }
15427 else
15428 {
15429 /* This can happen for a variable used in a
15430 late-specified return type of a local lambda, or for a
15431 local static or constant. Building a new VAR_DECL
15432 should be OK in all those cases. */
15435 /* Avoid infinite recursion (79640). */
15438 {
15439 /* We can't call cp_finish_decl, so handle the
15440 initializer by hand. */
15455 }
15462 }
15463 /* Remember this for subsequent uses. */
15466 }
15469 }
15470 else
15480 /* An OVERLOAD will always be a non-dependent overload set; an
15481 overload set from function scope will just be represented with an
15482 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15484 /* We must have marked any lookups as persistent. */
15500 {
15501 /* Template template argument like the following example need
15502 special treatment:
15504 template <template <class> class TT> struct C {};
15505 template <class T> struct D {
15506 template <class U> struct E {};
15507 C<E> c; // #1
15508 };
15509 D<int> d; // #2
15511 We are processing the template argument `E' in #1 for
15512 the template instantiation #2. Originally, `E' is a
15513 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15514 have to substitute this with one having context `D<int>'. */
15518 {
15519 /* When rewriting a constructor into a deduction guide, a
15520 non-dependent name can become dependent, so memtmpl<args>
15521 becomes context::template memtmpl<args>. */
15525 }
15527 }
15528 else
15529 /* Ordinary template template argument. */
15534 {
15535 /* Handle location wrappers by substituting the wrapped node
15536 first, *then* reusing the resulting type. Doing the type
15537 first ensures that we handle template parameters and
15538 parameter pack expansions. */
15542 }
15552 {
15556 }
15561 {
15570 /* We only want to compute the number of arguments. */
15573 else
15580 {
15582 /* Set TREE_USED for the benefit of -Wunused. */
15586 }
15594 {
15599 else
15606 else
15609 }
15610 else
15612 }
15614 {
15622 }
15623 /* Fall through */
15639 {
15646 }
15649 {
15650 tree object;
15651 tree name;
15656 {
15660 }
15663 {
15673 }
15678 in_decl);
15679 else
15682 }
15720 {
15724 }
15727 {
15732 }
15735 {
15739 }
15742 {
15750 }
15756 {
15763 }
15766 {
15773 }
15776 {
15783 }
15786 {
15787 /* Substituted template arguments */
15796 }
15799 {
15819 }
15844 /* Fall through. */
15847 {
15850 }
15851 else
15855 /* This is handled by tsubst_copy_and_build. */
15859 {
15863 }
15866 /* We shouldn't have built any of these during initial template
15867 generation. Instead, they should be built during instantiation
15868 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15872 {
15882 }
15900 {
15901 /* Instantiate any typedefs in the type. */
15906 }
15909 /* These can sometimes show up in a partial instantiation, but never
15910 involve template parms. */
15926 /* ??? There's no point in copying it for now, but maybe some
15927 day it will contain more information, such as a pointer back
15928 to the containing function, inlined copy or so. */
15932 /* We shouldn't get here, but keep going if !flag_checking. */
15936 }
15937 }
15939 /* Helper function for tsubst_omp_clauses, used for instantiation of
15940 OMP_CLAUSE_DECL of clauses. */
15942 static tree
15944 tree in_decl)
15945 {
15949 /* Handle an OpenMP array section represented as a TREE_LIST (or
15950 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15951 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15952 TREE_LIST. We can handle it exactly the same as an array section
15953 (purpose, value, and a chain), even though the nomenclature
15954 (low_bound, length, etc) is different. */
15956 {
15957 tree low_bound
15963 in_decl);
15972 }
15975 /* Undo convert_from_reference tsubst_expr could have called. */
15981 }
15983 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15985 static tree
15988 {
15993 {
15999 {
16002 {
16008 }
16009 /* FALLTHRU */
16024 in_decl);
16056 {
16059 {
16066 }
16067 else
16069 }
16072 in_decl);
16078 in_decl);
16086 in_decl);
16088 {
16091 }
16096 else
16099 in_decl,
16123 }
16126 {
16136 /* tsubst_expr on SCOPE_REF results in returning
16137 finish_non_static_data_member result. Undo that here. */
16141 {
16146 {
16150 CASE_CONVERT:
16159 /* FALLTHRU */
16163 }
16164 }
16170 {
16173 {
16176 }
16177 }
16181 }
16182 }
16186 {
16191 {
16194 }
16195 }
16197 }
16199 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
16201 static tree
16203 tree in_decl)
16204 {
16205 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
16225 {
16228 else
16229 {
16233 }
16234 }
16239 #undef RECUR
16240 }
16242 /* Used to temporarily communicate the list of #pragma omp parallel
16243 clauses to #pragma omp for instantiation if they are combined
16244 together. */
16248 /* Substitute one OMP_FOR iterator. */
16250 static void
16255 {
16256 #define RECUR(NODE) \
16257 tsubst_expr ((NODE), args, complain, in_decl, \
16258 integral_constant_expression_p)
16265 {
16268 }
16274 {
16275 /* We need to jump through some hoops to handle declarations in the
16276 init-statement, since we might need to handle auto deduction,
16277 but we need to keep control of initialization. */
16281 }
16282 else
16283 {
16285 {
16288 {
16292 {
16296 CASE_CONVERT:
16304 {
16307 }
16308 /* FALLTHRU */
16312 }
16313 }
16314 }
16315 else
16317 }
16328 {
16330 {
16331 /* Declare the variable, but don't let that initialize it. */
16336 }
16341 {
16346 }
16347 else
16354 }
16357 {
16358 /* Declare and initialize the variable. */
16361 }
16363 {
16367 {
16369 {
16375 {
16378 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
16383 }
16386 {
16388 decl);
16390 }
16393 {
16395 decl);
16397 }
16398 else
16400 }
16403 }
16405 {
16410 {
16413 }
16414 }
16415 }
16418 {
16422 }
16423 else
16427 {
16438 {
16446 }
16447 else
16453 {
16459 }
16463 {
16471 }
16472 else
16478 }
16484 #undef RECUR
16485 }
16487 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16488 of OMP_TARGET's body. */
16490 static tree
16492 {
16495 {
16504 }
16506 }
16508 /* Helper function for tsubst_expr. For decomposition declaration
16509 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16510 also the corresponding decls representing the identifiers
16511 of the decomposition declaration. Return DECL if successful
16512 or error_mark_node otherwise, set *FIRST to the first decl
16513 in the list chained through DECL_CHAIN and *CNT to the number
16514 of such decls. */
16516 static tree
16520 {
16525 decl2
16530 {
16532 {
16535 }
16547 else
16548 {
16552 }
16559 {
16562 }
16563 else
16565 }
16568 }
16570 /* Like tsubst_copy for expressions, etc. but also does semantic
16571 processing. */
16573 tree
16576 {
16577 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16578 #define RECUR(NODE) \
16579 tsubst_expr ((NODE), args, complain, in_decl, \
16580 integral_constant_expression_p)
16583 tree r;
16584 location_t loc;
16596 {
16598 {
16599 tree_stmt_iterator i;
16603 }
16618 else
16628 {
16630 tree init;
16636 {
16646 else
16648 }
16651 {
16652 /* We're in tsubst_lambda_expr, we've already inserted a new
16653 capture proxy, so look it up and register it. */
16654 tree inst;
16656 {
16657 inst = (retrieve_local_specialization
16660 }
16661 else
16662 {
16666 }
16669 }
16672 /* Don't copy the old closure; we'll create a new one in
16673 tsubst_lambda_expr. */
16675 else
16676 {
16680 {
16681 /* By marking the declaration as instantiated, we avoid
16682 trying to instantiate it. Since instantiate_decl can't
16683 handle local variables, and since we've already done
16684 all that needs to be done, that's the right thing to
16685 do. */
16690 /* Anonymous aggregates are a special case. */
16693 {
16696 {
16700 }
16702 }
16708 {
16713 }
16714 else
16715 {
16720 {
16721 /* For __PRETTY_FUNCTION__ we have to adjust the
16722 initializer. */
16726 }
16727 else
16731 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16736 {
16738 tree first;
16739 tree ndecl
16747 }
16748 else
16750 }
16751 }
16752 }
16755 }
16765 {
16769 }
16774 {
16775 /* Construct another range_for, if this is not a final
16776 substitution (for inside inside a generic lambda of a
16777 template). Otherwise convert to a regular for. */
16779 stmt = (processing_template_decl
16795 {
16799 }
16800 else
16801 {
16807 }
16813 }
16820 {
16824 }
16830 {
16834 }
16849 {
16850 /* We're partially instantiating a generic lambda, but the condition
16851 of the constexpr if is still dependent. Don't substitute into the
16852 branches now, just remember the template arguments. */
16860 }
16863 else
16864 {
16871 }
16877 {
16886 }
16894 else
16902 else
16923 {
16930 }
16934 {
16936 tree label;
16943 }
16949 /* Computed goto's must be tsubst'd into. On the other hand,
16950 non-computed gotos must not be; the identifier in question
16951 will have no binding. */
16953 else
16959 {
16975 }
16980 {
16985 }
16986 else
16987 {
16992 else
16999 else
17005 else
17007 }
17011 {
17015 {
17017 /* Prevent instantiate_decl from trying to instantiate
17018 this variable. We've already done all that needs to be
17019 done. */
17022 }
17027 }
17033 {
17034 /* Local classes are not independent templates; they are
17035 instantiated along with their containing function. And this
17036 way we don't have to deal with pushing out of one local class
17037 to instantiate a member of another local class. */
17038 /* Closures are handled by the LAMBDA_EXPR. */
17048 }
17052 {
17053 tree condition;
17056 condition =
17058 args,
17067 }
17073 in_decl);
17108 {
17121 in_decl);
17123 {
17130 }
17142 integral_constant_expression_p);
17153 else
17154 {
17162 }
17166 }
17171 /* FALLTHRU */
17178 in_decl);
17195 in_decl);
17206 {
17209 {
17210 /* For combined target teams, ensure the num_teams and
17211 thread_limit clause expressions are evaluated on the host,
17212 before entering the target construct. */
17213 tree c;
17219 {
17228 OMP_CLAUSE_FIRSTPRIVATE);
17232 }
17233 }
17234 }
17294 {
17299 {
17302 }
17308 }
17309 else
17310 {
17317 {
17320 }
17323 {
17328 {
17331 }
17337 }
17338 else
17339 {
17343 }
17346 }
17350 {
17356 {
17360 {
17365 }
17369 }
17370 else
17371 {
17376 }
17377 }
17381 {
17385 }
17398 /* If the first operand was a statement, we're done with it. */
17402 complain));
17416 integral_constant_expression_p));
17417 }
17420 out:
17423 #undef RECUR
17424 #undef RETURN
17425 }
17427 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17428 function. For description of the body see comment above
17429 cp_parser_omp_declare_reduction_exprs. */
17431 static void
17433 {
17439 tree_stmt_iterator tsi;
17450 {
17469 }
17471 {
17491 }
17492 }
17494 /* T is a postfix-expression that is not being used in a function
17495 call. Return the substituted version of T. */
17497 static tree
17499 tsubst_flags_t complain,
17500 tree in_decl)
17501 {
17505 else
17511 }
17513 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17514 instantiation context. Instantiating a pack expansion containing a lambda
17515 might result in multiple lambdas all based on the same lambda in the
17516 template. */
17518 tree
17520 {
17534 else
17542 {
17554 else
17559 {
17568 }
17569 else
17570 {
17576 }
17577 }
17583 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17601 else
17602 {
17603 /* Fix the type of 'this'. */
17609 {
17613 }
17614 else
17615 {
17619 }
17621 /* Let finish_function set this. */
17627 else
17628 /* Still increment function_depth so that we don't GC in the
17629 middle of an expression. */
17639 {
17640 /* We might not partially instantiate some parts of the function, so
17641 copy these flags from the original template. */
17647 }
17656 else
17659 /* The capture list was built up in reverse order; fix that now. */
17666 }
17673 }
17675 /* Like tsubst but deals with expressions and performs semantic
17676 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17678 tree
17680 tree args,
17681 tsubst_flags_t complain,
17682 tree in_decl,
17685 {
17686 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17687 #define RECUR(NODE) \
17688 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17690 integral_constant_expression_p)
17693 location_t loc;
17702 /* N3276 decltype magic only applies to calls at the top level or on the
17703 right side of a comma. */
17708 {
17711 /* Fall through. */
17713 {
17714 tree decl;
17715 cp_id_kind idk;
17720 {
17723 }
17725 /* Look up the name. */
17728 /* By convention, expressions use ERROR_MARK_NODE to indicate
17729 failure, not NULL_TREE. */
17735 integral_constant_expression_p,
17743 input_location);
17747 {
17751 }
17753 }
17756 {
17757 tree object;
17767 {
17772 }
17778 {
17781 }
17782 else
17789 else
17791 }
17794 {
17798 {
17799 /* A type conversion to reference type will be enclosed in
17800 such an indirect ref, but the substitution of the cast
17801 will have also added such an indirect ref. */
17803 }
17804 else
17812 }
17815 {
17819 }
17822 {
17826 {
17831 }
17833 /* We'll pass this to convert_nontype_argument again, we don't need
17834 to actually perform any conversion here. */
17840 flags));
17841 }
17844 {
17850 }
17857 {
17858 tree type;
17864 {
17869 }
17876 {
17894 }
17897 }
17930 else
17932 in_decl);
17967 {
17974 tree r = build_x_binary_op
17976 op0,
17978 ? ERROR_MARK
17980 op1,
17982 ? ERROR_MARK
17990 }
17993 {
17997 }
18013 /* Fall through */
18016 {
18017 tree r;
18025 {
18026 /* When there are no ARGS, we are trying to evaluate a
18027 non-dependent expression from the parser. Trying to do
18028 the substitutions may not work. */
18031 }
18032 else
18033 {
18038 else
18041 /*integral_constant_expression_p=*/
18045 }
18049 else
18053 {
18055 {
18057 {
18061 }
18062 else
18066 }
18068 }
18070 }
18073 {
18083 }
18099 {
18103 tree r = build_x_modify_expr
18106 /* TREE_NO_WARNING must be set if either the expression was
18107 parenthesized or it uses an operator such as >>= rather
18108 than plain assignment. In the former case, it was already
18109 set and must be copied. In the latter case,
18110 build_x_modify_expr sets it and it must not be reset
18111 here. */
18116 }
18121 /* Remember that there was a reference to this entity. */
18128 {
18133 tree ret;
18137 else
18138 {
18142 }
18144 /* If there was an initializer in the original tree, but it
18145 instantiated to an empty list, then we should pass a
18146 non-NULL empty vector to tell build_new that it was an
18147 empty initializer() rather than no initializer. This can
18148 only happen when the initializer is a pack expansion whose
18149 parameter packs are of length zero. */
18152 else
18153 {
18157 else
18158 {
18161 }
18162 }
18164 /* Avoid passing an enclosing decl to valid_array_size_p. */
18171 complain);
18179 }
18182 {
18188 complain));
18189 }
18192 {
18196 integral_constant_expression_p);
18198 op0,
18201 }
18204 {
18205 tree function;
18210 tree ret;
18213 /* Internal function with no arguments. */
18217 /* When we parsed the expression, we determined whether or
18218 not Koenig lookup should be performed. */
18221 {
18224 }
18226 {
18231 }
18233 {
18234 /* Do nothing; calling tsubst_copy_and_build on an identifier
18235 would incorrectly perform unqualified lookup again.
18237 Note that we can also have an IDENTIFIER_NODE if the earlier
18238 unqualified lookup found a member function; in that case
18239 koenig_p will be false and we do want to do the lookup
18240 again to find the instantiated member function.
18242 FIXME but doing that causes c++/15272, so we need to stop
18243 using IDENTIFIER_NODE in that situation. */
18245 }
18246 else
18247 {
18249 {
18255 }
18256 else
18261 /* Avoid error about taking the address of a constructor. */
18265 in_decl,
18267 integral_constant_expression_p);
18271 }
18276 {
18281 else
18282 {
18283 /* Expand the pack expansion and push each entry onto
18284 CALL_ARGS. */
18287 {
18292 {
18297 }
18298 }
18299 else
18300 {
18301 /* A partial substitution. Add one entry. */
18303 }
18304 }
18305 }
18307 /* We do not perform argument-dependent lookup if normal
18308 lookup finds a non-function, in accordance with the
18309 expected resolution of DR 218. */
18312 /* If lookup found a member function, the Koenig lookup is
18313 not appropriate, even if an unqualified-name was used
18314 to denote the function. */
18317 /* Only do this when substitution turns a dependent call
18318 into a non-dependent call. */
18326 {
18328 {
18329 /* For backwards compatibility and good diagnostics, try
18330 the unqualified lookup again if we aren't in SFINAE
18331 context. */
18332 tree unq = (tsubst_copy_and_build
18334 integral_constant_expression_p));
18336 {
18339 }
18342 {
18343 /* In a lambda fn, we have to be careful to not
18344 introduce new this captures. Legacy code can't
18345 be using lambdas anyway, so it's ok to be
18346 stricter. */
18351 "and no declarations were found by "
18352 "argument-dependent lookup at the point "
18359 else
18363 {
18374 {
18376 input_location);
18378 "declarations in dependent base %qT are "
18384 else
18388 }
18389 else
18391 "%qD declared here, later in the "
18394 {
18397 }
18398 }
18401 }
18402 }
18404 {
18409 }
18410 }
18412 /* Remember that there was a reference to this entity. */
18416 {
18419 }
18421 /* Put back tf_decltype for the actual call. */
18426 {
18430 {
18432 "wrong number of arguments to "
18435 }
18436 else
18438 input_location),
18443 /* Unsupported internal function with arguments. */
18445 }
18450 complain);
18452 {
18467 complain);
18468 else
18469 ret = (build_new_method_call
18474 complain));
18475 }
18476 else
18479 koenig_p,
18480 complain);
18485 {
18491 {
18497 {
18500 else
18502 /* The thunk location is not interesting. */
18504 }
18505 }
18506 }
18509 }
18512 {
18519 {
18521 {
18526 }
18527 else
18528 {
18533 }
18535 }
18536 else
18537 {
18540 }
18545 }
18548 {
18553 input_location));
18554 }
18557 {
18565 {
18566 /* We have pack expansions, so expand those and
18567 create a new list out of it. */
18570 tree chain;
18573 /* Expand the argument expressions. */
18581 /* Build the rest of the list. */
18586 /* Determine the number of arguments. */
18588 {
18591 }
18594 else
18595 {
18596 /* Since we only performed a partial substitution into
18597 the argument pack, we only RETURN (a single list
18598 node. */
18605 }
18607 /* Convert the argument vectors into a TREE_LIST */
18610 {
18611 /* Grab the Ith values. */
18612 i--;
18615 value
18619 /* Build the list (backwards). */
18621 }
18624 }
18640 }
18643 {
18644 tree object;
18645 tree object_type;
18646 tree member;
18647 tree r;
18651 /* Remember that there was a reference to this entity. */
18662 else
18668 {
18673 }
18677 {
18679 {
18684 {
18687 }
18689 {
18694 }
18695 }
18696 }
18699 {
18700 /* Lookup the template functions now that we know what the
18701 scope is. */
18709 {
18712 args);
18713 member = (adjust_result_of_qualified_name_lookup
18715 object_type));
18716 }
18717 else
18718 {
18720 input_location);
18722 }
18723 }
18727 {
18729 {
18733 else
18736 }
18738 }
18742 complain);
18746 }
18753 {
18761 tree r;
18766 /* We do not want to process the index of aggregate
18767 initializers as they are identifier nodes which will be
18768 looked up by digest_init. */
18774 {
18776 /* An identifier index is looked up in the type
18777 being initialized, not the current scope. */
18782 {
18783 /* Substitute into the pack expansion. */
18785 in_decl);
18789 ;
18791 /* Just move the argument into place. */
18793 else
18794 {
18795 /* Update the length of the final CONSTRUCTOR
18796 arguments vector, and note that we will need to
18797 copy.*/
18800 }
18801 }
18802 else
18804 }
18807 {
18812 {
18814 {
18819 }
18820 else
18822 }
18823 }
18829 {
18834 }
18838 }
18841 {
18844 {
18847 }
18848 else
18849 {
18852 }
18853 }
18858 /* Fall through */
18861 {
18863 /* ??? We're doing a subset of finish_id_expression here. */
18865 && !processing_template_decl
18866 && !cp_unevaluated_operand
18869 {
18871 /* Replace an evaluated use of the thread_local variable with
18872 a call to its wrapper. */
18874 }
18879 /* If the original type was a reference, we'll be wrapped in
18880 the appropriate INDIRECT_REF. */
18883 }
18886 {
18890 }
18893 {
18894 tree object_ptr
18901 }
18908 {
18919 }
18922 {
18928 integral_constant_expression_p);
18932 /* If the resulting list of expression statement is empty,
18933 fold it further into void_node. */
18938 }
18941 {
18945 }
18948 /* We can get here for a constant initializer of non-dependent type.
18949 FIXME stop folding in cp_parser_initializer_clause. */
18950 {
18952 complain);
18954 }
18958 integral_constant_expression_p));
18964 {
18969 complain));
18970 }
18977 /* We should only see these for location wrapper nodes, or within
18978 instantiate_non_dependent_expr (when args is NULL_TREE). */
18983 /* fallthrough. */
18986 /* Handle Objective-C++ constructs, if appropriate. */
18987 {
18988 tree subst
18993 }
18995 }
18997 #undef RECUR
18998 #undef RETURN
18999 out:
19002 }
19004 /* Verify that the instantiated ARGS are valid. For type arguments,
19005 make sure that the type's linkage is ok. For non-type arguments,
19006 make sure they are constants if they are integral or enumerations.
19007 Emit an error under control of COMPLAIN, and return TRUE on error. */
19009 static bool
19011 {
19015 {
19025 }
19027 {
19028 /* [basic.link]: A name with no linkage (notably, the name
19029 of a class or enumeration declared in a local scope)
19030 shall not be used to declare an entity with linkage.
19031 This implies that names with no linkage cannot be used as
19032 template arguments
19034 DR 757 relaxes this restriction for C++0x. */
19039 {
19040 /* DR 488 makes use of a type with no linkage cause
19041 type deduction to fail. */
19043 {
19046 else
19049 }
19051 }
19052 /* In order to avoid all sorts of complications, we do not
19053 allow variably-modified types as template arguments. */
19055 {
19059 }
19060 }
19061 /* Class template and alias template arguments should be OK. */
19063 ;
19064 /* A non-type argument of integral or enumerated type must be a
19065 constant. */
19070 {
19074 }
19076 }
19078 static bool
19080 {
19085 {
19088 }
19092 }
19094 /* We're out of SFINAE context now, so generate diagnostics for the access
19095 errors we saw earlier when instantiating D from TMPL and ARGS. */
19097 static void
19099 {
19111 }
19113 /* Instantiate the indicated variable, function, or alias template TMPL with
19114 the template arguments in TARG_PTR. */
19116 static tree
19118 {
19120 tree fndecl;
19121 tree gen_tmpl;
19122 tree spec;
19130 /* If this function is a clone, handle it specially. */
19132 {
19133 tree spec;
19134 tree clone;
19136 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
19137 DECL_CLONED_FUNCTION. */
19143 /* Look for the clone. */
19147 /* We should always have found the clone by now. */
19150 }
19155 /* Check to see if we already have this specialization. */
19159 /* targ_ptr only has the innermost template args, so add the outer ones
19160 from tmpl, which could be either a partial instantiation or gen_tmpl (in
19161 the case of a non-dependent call within a template definition). */
19162 targ_ptr = (add_outermost_template_args
19164 targ_ptr));
19166 /* It would be nice to avoid hashing here and then again in tsubst_decl,
19167 but it doesn't seem to be on the hot path. */
19176 {
19178 {
19182 }
19184 }
19187 complain))
19190 /* We are building a FUNCTION_DECL, during which the access of its
19191 parameters and return types have to be checked. However this
19192 FUNCTION_DECL which is the desired context for access checking
19193 is not built yet. We solve this chicken-and-egg problem by
19194 deferring all checks until we have the FUNCTION_DECL. */
19197 /* Instantiation of the function happens in the context of the function
19198 template, not the context of the overload resolution we're doing. */
19200 /* If there are dependent arguments, e.g. because we're doing partial
19201 ordering, make sure processing_template_decl stays set. */
19205 {
19209 }
19215 {
19216 /* We need to determine if we're using a partial or explicit
19217 specialization now, because the type of the variable could be
19218 different. */
19224 {
19229 }
19230 }
19232 /* Substitute template parameters to obtain the specialization. */
19240 {
19243 }
19245 /* The DECL_TI_TEMPLATE should always be the immediate parent
19246 template, not the most general template. */
19250 /* Now we know the specialization, compute access previously
19251 deferred. Do no access control for inheriting constructors,
19252 as we already checked access for the inherited constructor. */
19255 {
19260 }
19263 /* If we've just instantiated the main entry point for a function,
19264 instantiate all the alternate entry points as well. We do this
19265 by cloning the instantiation of the main entry point, not by
19266 instantiating the template clones. */
19271 {
19273 {
19274 /* Remember to reinstantiate when we're out of SFINAE so the user
19275 can see the errors. */
19277 }
19279 }
19281 }
19283 /* Wrapper for instantiate_template_1. */
19285 tree
19287 {
19288 tree ret;
19293 }
19295 /* Instantiate the alias template TMPL with ARGS. Also push a template
19296 instantiation level, which instantiate_template doesn't do because
19297 functions and variables have sufficient context established by the
19298 callers. */
19300 static tree
19302 {
19308 args =
19318 }
19320 /* PARM is a template parameter pack for FN. Returns true iff
19321 PARM is used in a deducible way in the argument list of FN. */
19323 static bool
19325 {
19328 {
19330 tree packs;
19336 {
19337 /* The template parameter pack is used in a function parameter
19338 pack. If this is the end of the parameter list, the
19339 template parameter pack is deducible. */
19342 else
19343 /* Otherwise, not. Well, it could be deduced from
19344 a non-pack parameter, but doing so would end up with
19345 a deduction mismatch, so don't bother. */
19347 }
19348 }
19349 /* The template parameter pack isn't used in any function parameter
19350 packs, but it might be used deeper, e.g. tuple<Args...>. */
19352 }
19354 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
19355 NARGS elements of the arguments that are being used when calling
19356 it. TARGS is a vector into which the deduced template arguments
19357 are placed.
19359 Returns either a FUNCTION_DECL for the matching specialization of FN or
19360 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
19361 true, diagnostics will be printed to explain why it failed.
19363 If FN is a conversion operator, or we are trying to produce a specific
19364 specialization, RETURN_TYPE is the return type desired.
19366 The EXPLICIT_TARGS are explicit template arguments provided via a
19367 template-id.
19369 The parameter STRICT is one of:
19371 DEDUCE_CALL:
19372 We are deducing arguments for a function call, as in
19373 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
19374 deducing arguments for a call to the result of a conversion
19375 function template, as in [over.call.object].
19377 DEDUCE_CONV:
19378 We are deducing arguments for a conversion function, as in
19379 [temp.deduct.conv].
19381 DEDUCE_EXACT:
19382 We are deducing arguments when doing an explicit instantiation
19383 as in [temp.explicit], when determining an explicit specialization
19384 as in [temp.expl.spec], or when taking the address of a function
19385 template, as in [temp.deduct.funcaddr]. */
19387 tree
19389 tree explicit_targs,
19390 tree targs,
19393 tree return_type,
19394 unification_kind_t strict,
19398 {
19399 tree parms;
19400 tree fntype;
19416 full_targs = (add_outermost_template_args
19418 targs));
19423 /* In C++0x, it's possible to have a function template whose type depends
19424 on itself recursively. This is most obvious with decltype, but can also
19425 occur with enumeration scope (c++/48969). So we need to catch infinite
19426 recursion and reject the substitution at deduction time; this function
19427 will return error_mark_node for any repeated substitution.
19429 This also catches excessive recursion such as when f<N> depends on
19430 f<N-1> across all integers, and returns error_mark_node for all the
19431 substitutions back up to the initial one.
19433 This is, of course, not reentrant. */
19442 {
19443 /* [temp.deduct]
19445 The specified template arguments must match the template
19446 parameters in kind (i.e., type, nontype, template), and there
19447 must not be more arguments than there are parameters;
19448 otherwise type deduction fails.
19450 Nontype arguments must match the types of the corresponding
19451 nontype template parameters, or must be convertible to the
19452 types of the corresponding nontype parameters as specified in
19453 _temp.arg.nontype_, otherwise type deduction fails.
19455 All references in the function type of the function template
19456 to the corresponding template parameters are replaced by the
19457 specified template argument values. If a substitution in a
19458 template parameter or in the function type of the function
19459 template results in an invalid type, type deduction fails. */
19470 explicit_targs);
19472 /* Adjust any explicit template arguments before entering the
19473 substitution context. */
19474 explicit_targs
19476 complain,
19482 /* Substitute the explicit args into the function type. This is
19483 necessary so that, for instance, explicitly declared function
19484 arguments can match null pointed constants. If we were given
19485 an incomplete set of explicit args, we must not do semantic
19486 processing during substitution as we could create partial
19487 instantiations. */
19489 {
19494 /* Dig out the actual parm. */
19497 {
19500 }
19502 {
19505 }
19508 /* No explicit argument for this template parameter. */
19512 {
19513 /* Mark the argument pack as "incomplete". We could
19514 still deduce more arguments during unification.
19515 We remove this mark in type_unification_real. */
19517 {
19521 }
19523 /* We have some incomplete argument packs. */
19525 }
19526 }
19529 {
19532 }
19535 /* Ignore any access checks; we'll see them again in
19536 instantiate_template and they might have the wrong
19537 access path at this point. */
19549 /* Place the explicitly specified arguments in TARGS. */
19553 }
19555 /* Never do unification on the 'this' parameter. */
19559 {
19560 /* We're deducing for a call to the result of a template conversion
19561 function. The parms we really want are in return_type. */
19565 }
19567 {
19576 }
19578 /* We allow incomplete unification without an error message here
19579 because the standard doesn't seem to explicitly prohibit it. Our
19580 callers must be ready to deal with unification failures in any
19581 event. */
19583 /* If we aren't explaining yet, push tinst context so we can see where
19584 any errors (e.g. from class instantiations triggered by instantiation
19585 of default template arguments) come from. If we are explaining, this
19586 context is redundant. */
19588 {
19591 }
19593 /* type_unification_real will pass back any access checks from default
19594 template argument substitution. */
19606 /* Now that we have bindings for all of the template arguments,
19607 ensure that the arguments deduced for the template template
19608 parameters have compatible template parameter lists. We cannot
19609 check this property before we have deduced all template
19610 arguments, because the template parameter types of a template
19611 template parameter might depend on prior template parameters
19612 deduced after the template template parameter. The following
19613 ill-formed example illustrates this issue:
19615 template<typename T, template<T> class C> void f(C<5>, T);
19617 template<int N> struct X {};
19619 void g() {
19620 f(X<5>(), 5l); // error: template argument deduction fails
19621 }
19623 The template parameter list of 'C' depends on the template type
19624 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19625 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19626 time that we deduce 'C'. */
19629 {
19632 }
19634 /* All is well so far. Now, check:
19636 [temp.deduct]
19638 When all template arguments have been deduced, all uses of
19639 template parameters in nondeduced contexts are replaced with
19640 the corresponding deduced argument values. If the
19641 substitution results in an invalid type, as described above,
19642 type deduction fails. */
19644 {
19647 }
19649 /* Also collect access checks from the instantiation. */
19662 /* Now perform any access checks encountered during substitution. */
19669 /* If we're looking for an exact match, check that what we got
19670 is indeed an exact match. It might not be if some template
19671 parameters are used in non-deduced contexts. But don't check
19672 for an exact match if we have dependent template arguments;
19673 in that case we're doing partial ordering, and we already know
19674 that we have two candidates that will provide the actual type. */
19676 {
19680 tree sarg
19686 {
19690 }
19691 }
19693 /* After doing deduction with the inherited constructor, actually return an
19694 instantiation of the inheriting constructor. */
19700 fail:
19703 {
19705 /* Reset once we're all the way out. */
19707 }
19710 }
19712 /* Adjust types before performing type deduction, as described in
19713 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19714 sections are symmetric. PARM is the type of a function parameter
19715 or the return type of the conversion function. ARG is the type of
19716 the argument passed to the call, or the type of the value
19717 initialized with the result of the conversion function.
19718 ARG_EXPR is the original argument expression, which may be null. */
19720 static int
19724 tree arg_expr)
19725 {
19729 {
19734 /* Swap PARM and ARG throughout the remainder of this
19735 function; the handling is precisely symmetric since PARM
19736 will initialize ARG rather than vice versa. */
19741 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19742 too, but here handle it by stripping the reference from PARM
19743 rather than by adding it to ARG. */
19751 /* Nothing else to do in this case. */
19756 }
19759 {
19760 /* [temp.deduct.call]
19762 If P is not a reference type:
19764 --If A is an array type, the pointer type produced by the
19765 array-to-pointer standard conversion (_conv.array_) is
19766 used in place of A for type deduction; otherwise,
19768 --If A is a function type, the pointer type produced by
19769 the function-to-pointer standard conversion
19770 (_conv.func_) is used in place of A for type deduction;
19771 otherwise,
19773 --If A is a cv-qualified type, the top level
19774 cv-qualifiers of A's type are ignored for type
19775 deduction. */
19780 else
19782 }
19784 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19785 reference to a cv-unqualified template parameter that does not represent a
19786 template parameter of a class template (during class template argument
19787 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19788 an lvalue, the type "lvalue reference to A" is used in place of A for type
19789 deduction. */
19796 /* try_one_overload doesn't provide an arg_expr, but
19797 functions are always lvalues. */
19801 /* [temp.deduct.call]
19803 If P is a cv-qualified type, the top level cv-qualifiers
19804 of P's type are ignored for type deduction. If P is a
19805 reference type, the type referred to by P is used for
19806 type deduction. */
19809 {
19812 }
19814 /* DR 322. For conversion deduction, remove a reference type on parm
19815 too (which has been swapped into ARG). */
19820 }
19822 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19823 template which does contain any deducible template parameters; check if
19824 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19825 unify_one_argument. */
19827 static int
19830 {
19831 tree type;
19835 else
19842 {
19846 }
19848 {
19853 }
19857 else
19859 }
19863 /* Returns true iff the expression EXPR is one from which a template
19864 argument can be deduced. In other words, if it's an undecorated
19865 use of a template non-type parameter. */
19867 static bool
19869 {
19870 /* Strip implicit conversions. */
19874 }
19876 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19877 deducible way; that is, if it has a max value of <PARM> - 1. */
19879 static bool
19881 {
19890 }
19892 /* Returns true iff the template arguments ARGS use a template parameter
19893 in a deducible way. */
19895 static bool
19897 {
19899 {
19904 else
19905 {
19912 else
19914 }
19917 }
19919 }
19921 /* Returns true iff TYPE contains any deducible references to template
19922 parameters, as per 14.8.2.5. */
19924 static bool
19926 {
19930 /* T
19931 cv-list T
19932 TT<T>
19933 TT<i>
19934 TT<> */
19939 /* T*
19940 T&
19941 T&& */
19945 /* T[integer-constant ]
19946 type [i] */
19951 /* T type ::*
19952 type T::*
19953 T T::*
19954 T (type ::*)()
19955 type (T::*)()
19956 type (type ::*)(T)
19957 type (T::*)(T)
19958 T (type ::*)(T)
19959 T (T::*)()
19960 T (T::*)(T) */
19963 || (uses_deducible_template_parms
19966 /* template-name <T> (where template-name refers to a class template)
19967 template-name <i> (where template-name refers to a class template) */
19974 /* type (T)
19975 T()
19976 T(T) */
19979 {
19988 }
19991 }
19993 /* Subroutine of type_unification_real and unify_pack_expansion to
19994 handle unification of a single P/A pair. Parameters are as
19995 for those functions. */
19997 static int
20001 {
20008 /* We can't deduce anything from this, but we might get all the
20009 template args from other function args. */
20012 /* Implicit conversions (Clause 4) will be performed on a function
20013 argument to convert it to the type of the corresponding function
20014 parameter if the parameter type contains no template-parameters that
20015 participate in template argument deduction. */
20018 /* For function parameters with no deducible template parameters,
20019 just return. We'll check non-dependent conversions later. */
20023 {
20025 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
20026 | UNIFY_ALLOW_MORE_CV_QUAL
20040 }
20042 /* We only do these transformations if this is the top-level
20043 parameter_type_list in a call or declaration matching; in other
20044 situations (nested function declarators, template argument lists) we
20045 won't be comparing a type to an expression, and we don't do any type
20046 adjustments. */
20048 {
20050 {
20053 {
20054 /* [temp.deduct.type] A template-argument can be
20055 deduced from a pointer to function or pointer
20056 to member function argument if the set of
20057 overloaded functions does not contain function
20058 templates and at most one of a set of
20059 overloaded functions provides a unique
20060 match. */
20064 /* If a unique match was not found, this is a
20065 non-deduced context, so we still succeed. */
20067 }
20073 }
20075 arg_strict |=
20077 }
20078 else
20083 /* For deduction from an init-list we need the actual list. */
20087 }
20089 /* for_each_template_parm callback that always returns 0. */
20091 static int
20093 {
20095 }
20097 /* for_each_template_parm any_fn callback to handle deduction of a template
20098 type argument from the type of an array bound. */
20100 static int
20102 {
20110 {
20116 }
20118 /* Keep walking. */
20120 }
20122 /* Try to deduce any not-yet-deduced template type arguments from the type of
20123 an array bound. This is handled separately from unify because 14.8.2.5 says
20124 "The type of a type parameter is only deduced from an array bound if it is
20125 not otherwise deduced." */
20127 static void
20129 {
20134 }
20136 /* Most parms like fn_type_unification.
20138 If SUBR is 1, we're being called recursively (to unify the
20139 arguments of a function or method parameter of a function
20140 template).
20142 CHECKS is a pointer to a vector of access checks encountered while
20143 substituting default template arguments. */
20145 static int
20147 tree full_targs,
20148 tree xparms,
20152 unification_kind_t strict,
20156 {
20161 tree parms;
20172 /* Reset the number of non-defaulted template arguments contained
20173 in TARGS. */
20176 again:
20184 {
20189 /* For a function parameter pack that occurs at the end of the
20190 parameter-declaration-list, the type A of each remaining
20191 argument of the call is compared with the type P of the
20192 declarator-id of the function parameter pack. */
20198 /* For a function parameter pack that does not occur at the
20199 end of the parameter-declaration-list, the type of the
20200 parameter pack is a non-deduced context. */
20207 explain_p))
20209 }
20214 {
20215 /* Unify the remaining arguments with the pack expansion type. */
20216 tree argvec;
20219 /* Allocate a TREE_VEC and copy in all of the arguments */
20224 /* Copy the parameter into parmvec. */
20230 /* Advance to the end of the list of parameters. */
20232 }
20234 /* Fail if we've reached the end of the parm list, and more args
20235 are present, and the parm list isn't variadic. */
20238 /* Fail if parms are left and they don't have default values and
20239 they aren't all deduced as empty packs (c++/57397). This is
20240 consistent with sufficient_parms_p. */
20243 {
20247 do
20248 {
20251 count++;
20253 }
20257 type_pack_p);
20258 }
20261 {
20262 tsubst_flags_t complain = (explain_p
20263 ? tf_warning_or_error
20268 {
20272 /* Clear the "incomplete" flags on all argument packs now so that
20273 substituting them into later default arguments works. */
20275 {
20278 }
20286 {
20291 }
20293 /* If this is an undeduced nontype parameter that depends on
20294 a type parameter, try another pass; its type may have been
20295 deduced from a later argument than the one from which
20296 this parameter can be deduced. */
20300 {
20303 }
20305 /* Core issue #226 (C++0x) [temp.deduct]:
20307 If a template argument has not been deduced, its
20308 default template argument, if any, is used.
20310 When we are in C++98 mode, TREE_PURPOSE will either
20311 be NULL_TREE or ERROR_MARK_NODE, so we do not need
20312 to explicitly check cxx_dialect here. */
20314 /* OK, there is a default argument. Wait until after the
20315 conversion check to do substitution. */
20318 /* If the type parameter is a parameter pack, then it will
20319 be deduced to an empty parameter pack. */
20321 {
20322 tree arg;
20325 {
20328 }
20329 else
20336 }
20339 }
20341 /* DR 1391: All parameters have args, now check non-dependent parms for
20342 convertibility. */
20346 {
20352 /* For a function parameter pack that occurs at the end of the
20353 parameter-declaration-list, the type A of each remaining
20354 argument of the call is compared with the type P of the
20355 declarator-id of the function parameter pack. */
20361 /* For a function parameter pack that does not occur at the
20362 end of the parameter-declaration-list, the type of the
20363 parameter pack is a non-deduced context. */
20372 explain_p))
20377 {
20383 else
20389 }
20390 }
20392 /* Now substitute into the default template arguments. */
20394 {
20410 {
20411 /* The type of this non-type parameter depends on undeduced
20412 parameters. Don't try to use its default argument yet,
20413 since we might deduce an argument for it on the next pass,
20414 but do check whether the arguments we already have cause
20415 substitution failure, so that that happens before we try
20416 later default arguments (78489). */
20419 NULL_TREE);
20423 else
20425 }
20426 else
20427 {
20430 {
20431 /* First instatiate in template context, in case we still
20432 depend on undeduced template parameters. */
20435 NULL_TREE);
20439 /* We replaced all the tparms, substitute again out of
20440 template context. */
20442 }
20445 NULL_TREE);
20452 else
20454 }
20463 {
20465 /* The position of the first default template argument,
20466 is also the number of non-defaulted arguments in TARGS.
20467 Record that. */
20470 }
20471 }
20475 }
20481 }
20483 /* Subroutine of type_unification_real. Args are like the variables
20484 at the call site. ARG is an overloaded function (or template-id);
20485 we try deducing template args from each of the overloads, and if
20486 only one succeeds, we go with that. Modifies TARGS and returns
20487 true on success. */
20489 static bool
20491 tree targs,
20492 tree parm,
20493 tree arg,
20494 unification_kind_t strict,
20497 {
20504 {
20507 }
20508 else
20512 /* Handle `&x' where `x' is some static or non-static member
20513 function name. */
20519 /* Strip baselink information. */
20524 {
20525 /* If we got some explicit template args, we need to plug them into
20526 the affected templates before we try to unify, in case the
20527 explicit args will completely resolve the templates in question. */
20534 {
20547 {
20552 {
20555 }
20556 }
20559 }
20560 /* If no templates (or more than one) are fully resolved by the
20561 explicit arguments, this template-id is a non-deduced context; it
20562 could still be OK if we deduce all template arguments for the
20563 enclosing call through other arguments. */
20566 }
20569 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20570 -- but the deduction does not succeed because the expression is
20571 not just the function on its own. */
20573 else
20575 {
20580 {
20583 }
20584 }
20586 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20587 to function or pointer to member function argument if the set of
20588 overloaded functions does not contain function templates and at most
20589 one of a set of overloaded functions provides a unique match.
20591 So if we found multiple possibilities, we return success but don't
20592 deduce anything. */
20595 {
20599 {
20604 /* Don't forget explicit template arguments in a pack. */
20608 }
20609 }
20614 }
20616 /* Core DR 115: In contexts where deduction is done and fails, or in
20617 contexts where deduction is not done, if a template argument list is
20618 specified and it, along with any default template arguments, identifies
20619 a single function template specialization, then the template-id is an
20620 lvalue for the function template specialization. */
20622 tree
20624 {
20637 {
20640 }
20642 {
20645 }
20647 {
20650 }
20653 {
20657 /* If we got some explicit template args, we need to plug them into
20658 the affected templates before we try to unify, in case the
20659 explicit args will completely resolve the templates in question. */
20667 {
20680 {
20683 {
20686 }
20688 {
20691 }
20692 }
20693 }
20695 {
20703 {
20704 tree base
20707 }
20711 }
20713 /* There were no good options and at least one bad one, so let the
20714 user know what the problem is. */
20716 }
20718 }
20720 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20721 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20722 different overloads deduce different arguments for a given parm.
20723 ADDR_P is true if the expression for which deduction is being
20724 performed was of the form "& fn" rather than simply "fn".
20726 Returns 1 on success. */
20728 static int
20730 tree orig_targs,
20731 tree targs,
20732 tree parm,
20733 tree arg,
20734 unification_kind_t strict,
20738 {
20740 tree tempargs;
20746 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20747 to function or pointer to member function argument if the set of
20748 overloaded functions does not contain function templates and at most
20749 one of a set of overloaded functions provides a unique match.
20751 So if this is a template, just return success. */
20763 /* We don't copy orig_targs for this because if we have already deduced
20764 some template args from previous args, unify would complain when we
20765 try to deduce a template parameter for the same argument, even though
20766 there isn't really a conflict. */
20773 /* First make sure we didn't deduce anything that conflicts with
20774 explicitly specified args. */
20776 {
20783 /* Since we're unifying against ourselves, we will fill in
20784 template args used in the function parm list with our own
20785 template parms. Discard them. */
20788 {
20789 /* Check that the argument at each index of the deduced argument pack
20790 is equivalent to the corresponding explicitly specified argument.
20791 We may have deduced more arguments than were explicitly specified,
20792 and that's OK. */
20794 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20795 that's wrong if we deduce the same argument pack from multiple
20796 function arguments: it's only incomplete the first time. */
20809 }
20812 }
20815 {
20820 }
20823 }
20825 /* PARM is a template class (perhaps with unbound template
20826 parameters). ARG is a fully instantiated type. If ARG can be
20827 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20828 TARGS are as for unify. */
20830 static tree
20833 {
20834 tree copy_of_targs;
20844 /* We need to make a new template argument vector for the call to
20845 unify. If we used TARGS, we'd clutter it up with the result of
20846 the attempted unification, even if this class didn't work out.
20847 We also don't want to commit ourselves to all the unifications
20848 we've already done, since unification is supposed to be done on
20849 an argument-by-argument basis. In other words, consider the
20850 following pathological case:
20852 template <int I, int J, int K>
20853 struct S {};
20855 template <int I, int J>
20856 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20858 template <int I, int J, int K>
20859 void f(S<I, J, K>, S<I, I, I>);
20861 void g() {
20862 S<0, 0, 0> s0;
20863 S<0, 1, 2> s2;
20865 f(s0, s2);
20866 }
20868 Now, by the time we consider the unification involving `s2', we
20869 already know that we must have `f<0, 0, 0>'. But, even though
20870 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20871 because there are two ways to unify base classes of S<0, 1, 2>
20872 with S<I, I, I>. If we kept the already deduced knowledge, we
20873 would reject the possibility I=1. */
20877 {
20881 }
20883 /* If unification failed, we're done. */
20889 }
20891 /* Given a template type PARM and a class type ARG, find the unique
20892 base type in ARG that is an instance of PARM. We do not examine
20893 ARG itself; only its base-classes. If there is not exactly one
20894 appropriate base class, return NULL_TREE. PARM may be the type of
20895 a partial specialization, as well as a plain template type. Used
20896 by unify. */
20898 static enum template_base_result
20901 {
20903 tree binfo;
20909 {
20910 /* The type could not be completed. */
20913 }
20915 /* Walk in inheritance graph order. The search order is not
20916 important, and this avoids multiple walks of virtual bases. */
20918 {
20923 {
20924 /* If there is more than one satisfactory baseclass, then:
20926 [temp.deduct.call]
20928 If they yield more than one possible deduced A, the type
20929 deduction fails.
20931 applies. */
20933 {
20936 }
20939 }
20940 }
20944 }
20946 /* Returns the level of DECL, which declares a template parameter. */
20948 static int
20950 {
20952 {
20962 }
20964 }
20966 /* Decide whether ARG can be unified with PARM, considering only the
20967 cv-qualifiers of each type, given STRICT as documented for unify.
20968 Returns nonzero iff the unification is OK on that basis. */
20970 static int
20972 {
20978 {
20979 /* Although a CVR qualifier is ignored when being applied to a
20980 substituted template parameter ([8.3.2]/1 for example), that
20981 does not allow us to unify "const T" with "int&" because both
20982 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20983 It is ok when we're allowing additional CV qualifiers
20984 at the outer level [14.8.2.1]/3,1st bullet. */
20994 }
21005 }
21007 /* Determines the LEVEL and INDEX for the template parameter PARM. */
21008 void
21010 {
21014 {
21017 }
21018 else
21019 {
21022 }
21023 }
21025 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
21026 do { \
21027 if (unify (TP, TA, P, A, S, EP)) \
21028 return 1; \
21029 } while (0)
21031 /* Unifies the remaining arguments in PACKED_ARGS with the pack
21032 expansion at the end of PACKED_PARMS. Returns 0 if the type
21033 deduction succeeds, 1 otherwise. STRICT is the same as in
21034 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
21035 function call argument list. We'll need to adjust the arguments to make them
21036 types. SUBR tells us if this is from a recursive call to
21037 type_unification_real, or for comparing two template argument
21038 lists. */
21040 static int
21044 {
21045 tree parm
21051 /* Add in any args remembered from an earlier partial instantiation. */
21059 /* Determine the parameter packs we will be deducing from the
21060 pattern, and record their current deductions. */
21063 {
21067 /* Only template parameter packs can be deduced, not e.g. function
21068 parameter packs or __bases or __integer_pack. */
21072 /* Determine the index and level of this parameter pack. */
21077 /* Keep track of the parameter packs and their corresponding
21078 argument packs. */
21081 }
21083 /* Loop through all of the arguments that have not yet been
21084 unified and unify each with the pattern. */
21086 {
21087 tree parm;
21091 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
21092 or the element of its argument pack at the current index if
21093 this argument was explicitly specified. */
21095 {
21104 {
21107 }
21109 }
21111 /* If we had explicit template arguments, substitute them into the
21112 pattern before deduction. */
21114 {
21115 /* Some arguments might still be unspecified or dependent. */
21123 NULL_TREE);
21128 }
21129 else
21132 /* Unify the pattern with the current argument. */
21134 explain_p))
21137 /* For each parameter pack, collect the deduced value. */
21139 {
21145 }
21146 }
21148 /* Verify that the results of unification with the parameter packs
21149 produce results consistent with what we've seen before, and make
21150 the deduced argument packs available. */
21152 {
21159 /* By default keep the original deduced argument pack.
21160 If necessary, more specific code is going to update the
21161 resulting deduced argument later down in this function. */
21165 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
21166 actually deduce anything. */
21174 {
21175 /* If we had fewer function args than explicit template args,
21176 just use the explicits. */
21181 }
21184 {
21185 tree result;
21186 /* Build the deduced *_ARGUMENT_PACK. */
21188 {
21191 }
21192 else
21197 /* Note the deduced argument packs for this parameter
21198 pack. */
21200 }
21204 {
21205 /* We only had the explicitly-provided arguments before, but
21206 now we have a complete set of arguments. */
21212 }
21213 else
21214 {
21220 /* Inconsistent unification of this parameter pack. */
21222 bad_old_arg,
21223 bad_new_arg);
21224 }
21225 }
21228 }
21230 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
21231 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
21232 parameters and return value are as for unify. */
21234 static int
21238 {
21239 tree parm_max;
21240 tree arg_max;
21244 /* Our representation of array types uses "N - 1" as the
21245 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
21246 not an integer constant. We cannot unify arbitrarily
21247 complex expressions, so we eliminate the MINUS_EXPRs
21248 here. */
21252 {
21255 }
21259 {
21260 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
21261 trying to unify the type of a variable with the type
21262 of a template parameter. For example:
21264 template <unsigned int N>
21265 void f (char (&) [N]);
21266 int g();
21267 void h(int i) {
21268 char a[g(i)];
21269 f(a);
21270 }
21272 Here, the type of the ARG will be "int [g(i)]", and
21273 may be a SAVE_EXPR, etc. */
21277 }
21279 /* If only one of the bounds used a MINUS_EXPR, compensate
21280 by adding one to the other bound. */
21283 integer_type_node,
21284 parm_max,
21285 integer_one_node);
21288 integer_type_node,
21289 arg_max,
21290 integer_one_node);
21294 }
21296 /* Returns whether T, a P or A in unify, is a type, template or expression. */
21300 static pa_kind_t
21302 {
21311 else
21313 }
21315 /* Deduce the value of template parameters. TPARMS is the (innermost)
21316 set of template parameters to a template. TARGS is the bindings
21317 for those template parameters, as determined thus far; TARGS may
21318 include template arguments for outer levels of template parameters
21319 as well. PARM is a parameter to a template function, or a
21320 subcomponent of that parameter; ARG is the corresponding argument.
21321 This function attempts to match PARM with ARG in a manner
21322 consistent with the existing assignments in TARGS. If more values
21323 are deduced, then TARGS is updated.
21325 Returns 0 if the type deduction succeeds, 1 otherwise. The
21326 parameter STRICT is a bitwise or of the following flags:
21328 UNIFY_ALLOW_NONE:
21329 Require an exact match between PARM and ARG.
21330 UNIFY_ALLOW_MORE_CV_QUAL:
21331 Allow the deduced ARG to be more cv-qualified (by qualification
21332 conversion) than ARG.
21333 UNIFY_ALLOW_LESS_CV_QUAL:
21334 Allow the deduced ARG to be less cv-qualified than ARG.
21335 UNIFY_ALLOW_DERIVED:
21336 Allow the deduced ARG to be a template base class of ARG,
21337 or a pointer to a template base class of the type pointed to by
21338 ARG.
21339 UNIFY_ALLOW_INTEGER:
21340 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
21341 case for more information.
21342 UNIFY_ALLOW_OUTER_LEVEL:
21343 This is the outermost level of a deduction. Used to determine validity
21344 of qualification conversions. A valid qualification conversion must
21345 have const qualified pointers leading up to the inner type which
21346 requires additional CV quals, except at the outer level, where const
21347 is not required [conv.qual]. It would be normal to set this flag in
21348 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
21349 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
21350 This is the outermost level of a deduction, and PARM can be more CV
21351 qualified at this point.
21352 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
21353 This is the outermost level of a deduction, and PARM can be less CV
21354 qualified at this point. */
21356 static int
21359 {
21361 tree targ;
21362 tree tparm;
21364 tsubst_flags_t complain = (explain_p
21365 ? tf_warning_or_error
21368 /* I don't think this will do the right thing with respect to types.
21369 But the only case I've seen it in so far has been array bounds, where
21370 signedness is the only information lost, and I think that will be
21371 okay. */
21379 /* We can't deduce anything from this, but we might get all the
21380 template args from other function args. */
21386 /* If PARM uses template parameters, then we can't bail out here,
21387 even if ARG == PARM, since we won't record unifications for the
21388 template parameters. We might need them if we're trying to
21389 figure out which of two things is more specialized. */
21393 /* Handle init lists early, so the rest of the function can assume
21394 we're dealing with a type. */
21396 {
21401 /* Replace T with std::initializer_list<T> for deduction. */
21408 /* We can only deduce from an initializer list argument if the
21409 parameter is std::initializer_list or an array; otherwise this
21410 is a non-deduced context. */
21415 else
21416 {
21418 /* Deduction is defined in terms of a single type, so just punt
21419 on the (bizarre) std::initializer_list<T...>. */
21422 }
21427 /* If ELTTYPE has no deducible template parms, skip deduction from
21429 else
21431 {
21438 {
21442 /* It should only be possible to get here for a call. */
21444 elt_strict |= maybe_adjust_types_for_deduction
21447 }
21450 explain_p);
21451 }
21455 {
21456 /* Also deduce from the length of the initializer list. */
21463 }
21465 /* If the std::initializer_list<T> deduction worked, replace the
21466 deduced A with std::initializer_list<A>. */
21468 {
21473 }
21475 }
21477 /* If parm and arg aren't the same kind of thing (template, type, or
21478 expression), fail early. */
21482 /* Immediately reject some pairs that won't unify because of
21483 cv-qualification mismatches. */
21486 /* It is the elements of the array which hold the cv quals of an array
21487 type, and the elements might be template type parms. We'll check
21488 when we recurse. */
21490 /* We check the cv-qualifiers when unifying with template type
21491 parameters below. We want to allow ARG `const T' to unify with
21492 PARM `T' for example, when computing which of two templates
21493 is more specialized, for example. */
21507 {
21511 /* In a type which contains a nested-name-specifier, template
21512 argument values cannot be deduced for template parameters used
21513 within the nested-name-specifier. */
21525 /* The PARM is not one we're trying to unify. Just check
21526 to see if it matches ARG. */
21527 {
21532 else
21534 }
21541 /* Check for mixed types and values. */
21549 {
21552 {
21553 /* First try to match ARG directly. */
21555 explain_p);
21557 {
21558 /* Otherwise, look for a suitable base of ARG, as below. */
21565 }
21566 }
21567 /* ARG must be constructed from a template class or a template
21568 template parameter. */
21573 /* Deduce arguments T, i from TT<T> or TT<i>. */
21579 /* Fall through to deduce template name. */
21580 }
21584 {
21585 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21587 /* Simple cases: Value already set, does match or doesn't. */
21592 }
21593 else
21594 {
21595 /* If PARM is `const T' and ARG is only `int', we don't have
21596 a match unless we are allowing additional qualification.
21597 If ARG is `const int' and PARM is just `T' that's OK;
21598 that binds `const int' to `T'. */
21603 /* Consider the case where ARG is `const volatile int' and
21604 PARM is `const T'. Then, T should be `volatile int'. */
21605 arg = cp_build_qualified_type_real
21610 /* Simple cases: Value already set, does match or doesn't. */
21616 /* Make sure that ARG is not a variable-sized array. (Note
21617 that were talking about variable-sized arrays (like
21618 `int[n]'), rather than arrays of unknown size (like
21619 `int[]').) We'll get very confused by such a type since
21620 the bound of the array is not constant, and therefore
21621 not mangleable. Besides, such types are not allowed in
21622 ISO C++, so we can do as we please here. We do allow
21623 them for 'auto' deduction, since that isn't ABI-exposed. */
21627 /* Strip typedefs as in convert_template_argument. */
21629 }
21631 /* If ARG is a parameter pack or an expansion, we cannot unify
21632 against it unless PARM is also a parameter pack. */
21637 /* If the argument deduction results is a METHOD_TYPE,
21638 then there is a problem.
21639 METHOD_TYPE doesn't map to any real C++ type the result of
21640 the deduction can not be of that type. */
21654 {
21655 /* The PARM is not one we're trying to unify. Just check
21656 to see if it matches ARG. */
21662 }
21668 {
21672 /* We're deducing from an array bound, the type doesn't matter. */
21678 }
21680 /* [temp.deduct.type] If, in the declaration of a function template
21681 with a non-type template-parameter, the non-type
21682 template-parameter is used in an expression in the function
21683 parameter-list and, if the corresponding template-argument is
21684 deduced, the template-argument type shall match the type of the
21685 template-parameter exactly, except that a template-argument
21686 deduced from an array bound may be of any integral type.
21687 The non-type parameter might use already deduced type parameters. */
21690 /* We don't have enough levels of args to do any substitution. This
21692 else
21693 {
21699 {
21703 }
21704 }
21707 /* Template-parameter dependent expression. Just accept it for now.
21708 It will later be processed in convert_template_argument. */
21709 ;
21715 /* Convert the ARG to the type of PARM; the deduced non-type
21716 template argument must exactly match the types of the
21717 corresponding parameter. */
21720 {
21721 /* We haven't deduced the type of this parameter yet. */
21723 /* We deduce from array bounds in try_array_deduction. */
21725 {
21726 /* Deduce it from the non-type argument. */
21731 }
21732 else
21733 /* Try again later. */
21735 }
21736 else
21739 /* If ARG is a parameter pack or an expansion, we cannot unify
21740 against it unless PARM is also a parameter pack. */
21745 {
21748 }
21753 {
21754 /* A pointer-to-member constant can be unified only with
21755 another constant. */
21759 /* Just unify the class member. It would be useless (and possibly
21760 wrong, depending on the strict flags) to unify also
21761 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21762 arg refer to the same variable, even if through different
21763 classes. For instance:
21765 struct A { int x; };
21766 struct B : A { };
21768 Unification of &A::x and &B::x must succeed. */
21771 }
21774 {
21778 /* [temp.deduct.call]
21780 A can be another pointer or pointer to member type that can
21781 be converted to the deduced A via a qualification
21782 conversion (_conv.qual_).
21784 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21785 This will allow for additional cv-qualification of the
21786 pointed-to types if appropriate. */
21789 /* The derived-to-base conversion only persists through one
21790 level of pointers. */
21795 }
21827 /* We have already checked cv-qualification at the top of the
21828 function. */
21832 /* As far as unification is concerned, this wins. Later checks
21833 will invalidate it if necessary. */
21836 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21837 /* Type INTEGER_CST can come from ordinary constant template args. */
21849 {
21859 /* Check for pack expansions in the parameters. */
21861 {
21863 {
21865 /* We can unify against something with a trailing
21866 parameter pack. */
21868 else
21869 /* [temp.deduct.type]/9: If the template argument list of
21870 P contains a pack expansion that is not the last
21871 template argument, the entire template argument list
21872 is a non-deduced context. */
21874 }
21875 }
21877 /* If we don't have enough arguments to satisfy the parameters
21878 (not counting the pack expression at the end), or we have
21879 too many arguments for a parameter list that doesn't end in
21880 a pack expression, we can't unify. */
21886 /* Unify all of the parameters that precede the (optional)
21887 pack expression. */
21889 {
21894 }
21897 DEDUCE_EXACT,
21900 }
21908 {
21916 }
21921 {
21925 {
21926 /* First, we try to unify the PARM and ARG directly. */
21931 {
21932 /* Fallback to the special case allowed in
21933 [temp.deduct.call]:
21935 If P is a class, and P has the form
21936 template-id, then A can be a derived class of
21937 the deduced A. Likewise, if P is a pointer to
21938 a class of the form template-id, A can be a
21939 pointer to a derived class pointed to by the
21940 deduced A. */
21946 {
21947 /* Don't give the derived diagnostic if we're
21948 already dealing with the same template. */
21949 bool same_template
21955 }
21956 }
21957 }
21961 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21962 Then, we should unify `int' and `U'. */
21964 else
21965 /* There's no chance of unification succeeding. */
21970 }
21977 {
21980 tree a;
21986 /* CV qualifications for methods can never be deduced, they must
21987 match exactly. We need to check them explicitly here,
21988 because type_unification_real treats them as any other
21989 cv-qualified parameter. */
21991 && (!check_cv_quals_for_unify
22019 {
22031 }
22034 }
22037 /* Unify a pointer to member with a pointer to member function, which
22038 deduces the type of the member as a function type. */
22040 {
22041 /* Check top-level cv qualifiers */
22049 /* Determine the type of the function we are unifying against. */
22053 }
22072 /* Matched cases are handled by the ARG == PARM test above. */
22076 /* We might get a variable as a non-type template argument in parm if the
22077 corresponding parameter is type-dependent. Make any necessary
22078 adjustments based on whether arg is a reference. */
22082 {
22087 }
22088 /* Now use the normal expression code to check whether they match. */
22099 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
22100 or UNDERLYING_TYPE nodes. */
22104 /* Unification fails if we hit an error node. */
22109 {
22119 }
22120 /* FALLTHRU */
22123 /* An unresolved overload is a nondeduced context. */
22127 expr:
22128 /* We must be looking at an expression. This can happen with
22129 something like:
22131 template <int I>
22132 void foo(S<I>, S<I + 2>);
22134 This is a "nondeduced context":
22136 [deduct.type]
22138 The nondeduced contexts are:
22140 --A type that is a template-id in which one or more of
22141 the template-arguments is an expression that references
22142 a template-parameter.
22144 In these cases, we assume deduction succeeded, but don't
22145 actually infer any unifications. */
22150 else
22152 }
22153 }
22154 #undef RECUR_AND_CHECK_FAILURE
22155 \f
22156 /* Note that DECL can be defined in this translation unit, if
22157 required. */
22159 static void
22161 {
22162 tree clone;
22166 }
22168 /* Called if RESULT is explicitly instantiated, or is a member of an
22169 explicitly instantiated class. */
22171 void
22173 {
22176 /* If this entity has already been written out, it's too late to
22177 make any modifications. */
22181 /* For anonymous namespace we don't need to do anything. */
22183 {
22186 }
22189 /* The TREE_PUBLIC flag for function declarations will have been
22190 set correctly by tsubst. */
22193 /* This might have been set by an earlier implicit instantiation. */
22198 else
22199 {
22202 /* Always make artificials weak. */
22205 /* For WIN32 we also want to put explicit instantiations in
22206 linkonce sections. */
22211 /* If the function has already been instantiated, clear DECL_EXTERNAL,
22212 since start_preparsed_function wouldn't have if we had an earlier
22213 extern explicit instantiation. */
22215 }
22217 /* If EXTERN_P, then this function will not be emitted -- unless
22218 followed by an explicit instantiation, at which point its linkage
22219 will be adjusted. If !EXTERN_P, then this function will be
22220 emitted here. In neither circumstance do we want
22221 import_export_decl to adjust the linkage. */
22223 }
22225 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
22226 important template arguments. If any are missing, we check whether
22227 they're important by using error_mark_node for substituting into any
22228 args that were used for partial ordering (the ones between ARGS and END)
22229 and seeing if it bubbles up. */
22231 static bool
22233 {
22238 {
22241 }
22243 {
22247 }
22249 }
22251 /* Given two function templates PAT1 and PAT2, return:
22253 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
22254 -1 if PAT2 is more specialized than PAT1.
22255 0 if neither is more specialized.
22257 LEN indicates the number of parameters we should consider
22258 (defaulted parameters should not be considered).
22260 The 1998 std underspecified function template partial ordering, and
22261 DR214 addresses the issue. We take pairs of arguments, one from
22262 each of the templates, and deduce them against each other. One of
22263 the templates will be more specialized if all the *other*
22264 template's arguments deduce against its arguments and at least one
22265 of its arguments *does* *not* deduce against the other template's
22266 corresponding argument. Deduction is done as for class templates.
22267 The arguments used in deduction have reference and top level cv
22268 qualifiers removed. Iff both arguments were originally reference
22269 types *and* deduction succeeds in both directions, an lvalue reference
22270 wins against an rvalue reference and otherwise the template
22271 with the more cv-qualified argument wins for that pairing (if
22272 neither is more cv-qualified, they both are equal). Unlike regular
22273 deduction, after all the arguments have been deduced in this way,
22274 we do *not* verify the deduced template argument values can be
22275 substituted into non-deduced contexts.
22277 The logic can be a bit confusing here, because we look at deduce1 and
22278 targs1 to see if pat2 is at least as specialized, and vice versa; if we
22279 can find template arguments for pat1 to make arg1 look like arg2, that
22280 means that arg2 is at least as specialized as arg1. */
22282 int
22284 {
22297 /* Remove the this parameter from non-static member functions. If
22298 one is a non-static member function and the other is not a static
22299 member function, remove the first parameter from that function
22300 also. This situation occurs for operator functions where we
22301 locate both a member function (with this pointer) and non-member
22302 operator (with explicit first operand). */
22304 {
22309 }
22311 {
22314 {
22315 len--;
22317 }
22318 }
22320 /* If only one is a conversion operator, they are unordered. */
22324 /* Consider the return type for a conversion function */
22326 {
22329 len++;
22330 }
22332 processing_template_decl++;
22338 /* Stop when an ellipsis is seen. */
22340 {
22351 {
22352 /* When both arguments are pack expansions, we need only
22353 unify the patterns themselves. */
22357 /* This is the last comparison we need to do. */
22359 }
22361 /* DR 1847: If a particular P contains no template-parameters that
22362 participate in template argument deduction, that P is not used to
22363 determine the ordering. */
22369 {
22373 }
22376 {
22380 }
22386 {
22392 /* Setup the parameter vector, which contains only ARG1. */
22395 /* Setup the argument vector, which contains the remaining
22396 arguments. */
22405 /* We cannot deduce in the other direction, because ARG1 is
22406 a pack expansion but ARG2 is not. */
22408 }
22410 {
22416 /* Setup the parameter vector, which contains only ARG1. */
22419 /* Setup the argument vector, which contains the remaining
22420 arguments. */
22429 /* We cannot deduce in the other direction, because ARG2 is
22430 a pack expansion but ARG1 is not.*/
22432 }
22434 else
22435 {
22436 /* The normal case, where neither argument is a pack
22437 expansion. */
22444 }
22446 /* If we couldn't deduce arguments for tparms1 to make arg1 match
22447 arg2, then arg2 is not as specialized as arg1. */
22453 /* "If, for a given type, deduction succeeds in both directions
22454 (i.e., the types are identical after the transformations above)
22455 and both P and A were reference types (before being replaced with
22456 the type referred to above):
22457 - if the type from the argument template was an lvalue reference and
22458 the type from the parameter template was not, the argument type is
22459 considered to be more specialized than the other; otherwise,
22460 - if the type from the argument template is more cv-qualified
22461 than the type from the parameter template (as described above),
22462 the argument type is considered to be more specialized than the other;
22463 otherwise,
22464 - neither type is more specialized than the other." */
22467 {
22469 {
22472 else
22474 }
22476 {
22481 }
22482 }
22485 /* We've failed to deduce something in either direction.
22486 These must be unordered. */
22489 next:
22493 /* We have already processed all of the arguments in our
22494 handing of the pack expansion type. */
22499 }
22501 /* "In most cases, all template parameters must have values in order for
22502 deduction to succeed, but for partial ordering purposes a template
22503 parameter may remain without a value provided it is not used in the
22504 types being used for partial ordering."
22506 Thus, if we are missing any of the targs1 we need to substitute into
22507 origs1, then pat2 is not as specialized as pat1. This can happen when
22508 there is a nondeduced context. */
22514 processing_template_decl--;
22516 /* If both deductions succeed, the partial ordering selects the more
22517 constrained template. */
22519 {
22524 }
22526 /* All things being equal, if the next argument is a pack expansion
22527 for one function but not for the other, prefer the
22528 non-variadic function. FIXME this is bogus; see c++/41958. */
22532 {
22535 }
22541 else
22543 }
22545 /* Determine which of two partial specializations of TMPL is more
22546 specialized.
22548 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22549 to the first partial specialization. The TREE_PURPOSE is the
22550 innermost set of template parameters for the partial
22551 specialization. PAT2 is similar, but for the second template.
22553 Return 1 if the first partial specialization is more specialized;
22554 -1 if the second is more specialized; 0 if neither is more
22555 specialized.
22557 See [temp.class.order] for information about determining which of
22558 two templates is more specialized. */
22560 static int
22562 {
22563 tree targs;
22572 /* Just like what happens for functions, if we are ordering between
22573 different template specializations, we may encounter dependent
22574 types in the arguments, and we need our dependency check functions
22575 to behave correctly. */
22579 {
22582 }
22586 {
22589 }
22592 /* If both deductions succeed, the partial ordering selects the more
22593 constrained template. */
22597 /* In the case of a tie where at least one of the templates
22598 has a parameter pack at the end, the template with the most
22599 non-packed parameters wins. */
22601 && any_deductions
22604 {
22610 /* We don't count the pack expansion at the end. */
22620 }
22623 }
22625 /* Return the template arguments that will produce the function signature
22626 DECL from the function template FN, with the explicit template
22627 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22628 also match. Return NULL_TREE if no satisfactory arguments could be
22629 found. */
22631 static tree
22633 {
22637 tree decl_arg_types;
22640 tree arg;
22644 /* Never do unification on the 'this' parameter. */
22665 }
22667 /* Return the innermost template arguments that, when applied to a partial
22668 specialization SPEC_TMPL of TMPL, yield the ARGS.
22670 For example, suppose we have:
22672 template <class T, class U> struct S {};
22673 template <class T> struct S<T*, int> {};
22675 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22676 partial specialization and the ARGS will be {double*, int}. The resulting
22677 vector will be {double}, indicating that `T' is bound to `double'. */
22679 static tree
22681 {
22683 tree spec_args
22686 tree deduced_args;
22687 tree innermost_deduced_args;
22691 {
22695 innermost_deduced_args);
22696 }
22697 else
22701 again:
22710 {
22712 {
22718 }
22720 }
22723 {
22726 }
22728 /* Verify that nondeduced template arguments agree with the type
22729 obtained from argument deduction.
22731 For example:
22733 struct A { typedef int X; };
22734 template <class T, class U> struct C {};
22735 template <class T> struct C<T, typename T::X> {};
22737 Then with the instantiation `C<A, int>', we can deduce that
22738 `T' is `A' but unify () does not check whether `typename T::X'
22739 is `int'. */
22750 /* We only need to check the innermost arguments; the other
22751 arguments will always agree. */
22756 /* Now that we have bindings for all of the template arguments,
22757 ensure that the arguments deduced for the template template
22758 parameters have compatible template parameter lists. See the use
22759 of template_template_parm_bindings_ok_p in fn_type_unification
22760 for more information. */
22765 }
22767 // Compare two function templates T1 and T2 by deducing bindings
22768 // from one against the other. If both deductions succeed, compare
22769 // constraints to see which is more constrained.
22770 static int
22772 {
22777 {
22780 }
22783 {
22786 }
22788 // If both deductions succeed, then one may be more constrained.
22793 }
22795 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22796 Return the TREE_LIST node with the most specialized template, if
22797 any. If there is no most specialized template, the error_mark_node
22798 is returned.
22800 Note that this function does not look at, or modify, the
22801 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22802 returned is one of the elements of INSTANTIATIONS, callers may
22803 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22804 and retrieve it from the value returned. */
22806 tree
22808 {
22815 {
22821 {
22822 /* Equally specialized, move to next function. If there
22823 is no next function, nothing's most specialized. */
22828 }
22829 }
22832 /* Now verify that champ is better than everything earlier in the
22833 instantiation list. */
22836 {
22839 }
22840 }
22842 processing_template_decl--;
22848 }
22850 /* If DECL is a specialization of some template, return the most
22851 general such template. Otherwise, returns NULL_TREE.
22853 For example, given:
22855 template <class T> struct S { template <class U> void f(U); };
22857 if TMPL is `template <class U> void S<int>::f(U)' this will return
22858 the full template. This function will not trace past partial
22859 specializations, however. For example, given in addition:
22861 template <class T> struct S<T*> { template <class U> void f(U); };
22863 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22864 `template <class T> template <class U> S<T*>::f(U)'. */
22866 tree
22868 {
22870 {
22873 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22874 template friend, or a FIELD_DECL for a capture pack. */
22877 }
22879 /* Look for more and more general templates. */
22881 {
22882 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22883 (See cp-tree.h for details.) */
22892 /* Stop if we run into an explicitly specialized class template. */
22899 }
22902 }
22904 /* Return the most specialized of the template partial specializations
22905 which can produce TARGET, a specialization of some class or variable
22906 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22907 a TEMPLATE_DECL node corresponding to the partial specialization, while
22908 the TREE_PURPOSE is the set of template arguments that must be
22909 substituted into the template pattern in order to generate TARGET.
22911 If the choice of partial specialization is ambiguous, a diagnostic
22912 is issued, and the error_mark_node is returned. If there are no
22913 partial specializations matching TARGET, then NULL_TREE is
22914 returned, indicating that the primary template should be used. */
22916 static tree
22918 {
22920 tree t;
22921 tree champ;
22928 {
22932 }
22934 {
22937 }
22939 {
22943 }
22944 else
22949 /* For determining which partial specialization to use, only the
22950 innermost args are interesting. */
22952 {
22955 }
22958 {
22959 tree spec_args;
22963 {
22964 /* Substitute in the template args from the enclosing class. */
22968 }
22975 {
22979 /* Keep the candidate only if the constraints are satisfied,
22980 or if we're not compiling with concepts. */
22983 {
22986 }
22987 }
22988 }
22998 {
23001 ;
23002 else
23003 {
23005 {
23008 {
23011 }
23012 }
23014 }
23015 }
23019 {
23022 {
23025 }
23026 }
23029 {
23036 else
23040 {
23045 }
23048 }
23051 }
23053 /* Explicitly instantiate DECL. */
23055 void
23057 {
23062 /* An error occurred, for which grokdeclarator has already issued
23063 an appropriate message. */
23066 {
23069 }
23075 {
23076 /* There is an asymmetry here in the way VAR_DECLs and
23077 FUNCTION_DECLs are handled by grokdeclarator. In the case of
23078 the latter, the DECL we get back will be marked as a
23079 template instantiation, and the appropriate
23080 DECL_TEMPLATE_INFO will be set up. This does not happen for
23081 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
23082 should handle VAR_DECLs as it currently handles
23083 FUNCTION_DECLs. */
23085 {
23088 }
23091 {
23094 }
23096 {
23101 }
23102 }
23104 {
23107 }
23108 else
23111 /* Check for various error cases. Note that if the explicit
23112 instantiation is valid the RESULT will currently be marked as an
23113 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
23114 until we get here. */
23117 {
23118 /* DR 259 [temp.spec].
23120 Both an explicit instantiation and a declaration of an explicit
23121 specialization shall not appear in a program unless the explicit
23122 instantiation follows a declaration of the explicit specialization.
23124 For a given set of template parameters, if an explicit
23125 instantiation of a template appears after a declaration of an
23126 explicit specialization for that template, the explicit
23127 instantiation has no effect. */
23129 }
23131 {
23132 /* [temp.spec]
23134 No program shall explicitly instantiate any template more
23135 than once.
23137 We check DECL_NOT_REALLY_EXTERN so as not to complain when
23138 the first instantiation was `extern' and the second is not,
23139 and EXTERN_P for the opposite case. */
23142 /* If an "extern" explicit instantiation follows an ordinary
23143 explicit instantiation, the template is instantiated. */
23146 }
23148 {
23151 }
23153 {
23156 }
23159 ;
23161 {
23164 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
23167 }
23168 else
23176 }
23178 static void
23180 {
23186 {
23189 }
23190 }
23192 /* Called from do_type_instantiation through binding_table_foreach to
23193 do recursive instantiation for the type bound in ENTRY. */
23194 static void
23196 {
23203 }
23205 /* Perform an explicit instantiation of template class T. STORAGE, if
23206 non-null, is the RID for extern, inline or static. COMPLAIN is
23207 nonzero if this is called from the parser, zero if called recursively,
23208 since the standard is unclear (as detailed below). */
23210 void
23212 {
23222 {
23223 tree tmpl =
23227 else
23230 }
23235 {
23238 t);
23240 }
23243 {
23245 {
23247 {
23250 "ISO C++ 1998 forbids the use of %<extern%> on "
23252 }
23253 else
23255 "ISO C++ forbids the use of %qE"
23257 }
23265 else
23266 {
23268 storage);
23270 }
23271 }
23274 {
23275 /* DR 259 [temp.spec].
23277 Both an explicit instantiation and a declaration of an explicit
23278 specialization shall not appear in a program unless the explicit
23279 instantiation follows a declaration of the explicit specialization.
23281 For a given set of template parameters, if an explicit
23282 instantiation of a template appears after a declaration of an
23283 explicit specialization for that template, the explicit
23284 instantiation has no effect. */
23286 }
23288 {
23289 /* [temp.spec]
23291 No program shall explicitly instantiate any template more
23292 than once.
23294 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
23295 instantiation was `extern'. If EXTERN_P then the second is.
23296 These cases are OK. */
23303 /* If we've already instantiated the template, just return now. */
23306 }
23314 /* In contrast to implicit instantiation, where only the
23315 declarations, and not the definitions, of members are
23316 instantiated, we have here:
23318 [temp.explicit]
23320 The explicit instantiation of a class template specialization
23321 implies the instantiation of all of its members not
23322 previously explicitly specialized in the translation unit
23323 containing the explicit instantiation.
23325 Of course, we can't instantiate member template classes, since we
23326 don't have any arguments for them. Note that the standard is
23327 unclear on whether the instantiation of the members are
23328 *explicit* instantiations or not. However, the most natural
23329 interpretation is that it should be an explicit
23330 instantiation. */
23334 && !static_p
23337 {
23342 }
23347 }
23349 /* Given a function DECL, which is a specialization of TMPL, modify
23350 DECL to be a re-instantiation of TMPL with the same template
23351 arguments. TMPL should be the template into which tsubst'ing
23352 should occur for DECL, not the most general template.
23354 One reason for doing this is a scenario like this:
23356 template <class T>
23357 void f(const T&, int i);
23359 void g() { f(3, 7); }
23361 template <class T>
23362 void f(const T& t, const int i) { }
23364 Note that when the template is first instantiated, with
23365 instantiate_template, the resulting DECL will have no name for the
23366 first parameter, and the wrong type for the second. So, when we go
23367 to instantiate the DECL, we regenerate it. */
23369 static void
23371 {
23372 /* The arguments used to instantiate DECL, from the most general
23373 template. */
23374 tree code_pattern;
23378 /* Make sure that we can see identifiers, and compute access
23379 correctly. */
23383 {
23384 tree decl_parm;
23385 tree pattern_parm;
23386 tree specs;
23400 specs);
23402 /* Merge parameter declarations. */
23405 pattern_parm
23409 {
23410 tree parm_type;
23411 tree attributes;
23416 NULL_TREE);
23422 {
23425 }
23428 }
23429 /* Merge any parameters that match with the function parameter
23430 pack. */
23432 {
23434 tree expanded_types;
23435 /* Expand the TYPE_PACK_EXPANSION that provides the types for
23436 the parameters in this function parameter pack. */
23441 {
23442 tree parm_type;
23443 tree attributes;
23446 /* Rename the parameter to include the index. */
23455 {
23458 }
23460 }
23461 }
23462 /* Merge additional specifiers from the CODE_PATTERN. */
23466 }
23468 {
23478 }
23479 else
23483 }
23485 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
23486 substituted to get DECL. */
23488 tree
23490 {
23493 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23494 for the instantiation. This is not always the most general
23495 template. Consider, for example:
23497 template <class T>
23498 struct S { template <class U> void f();
23499 template <> void f<int>(); };
23501 and an instantiation of S<double>::f<int>. We want TD to be the
23502 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23504 more general template. */
23506 /* We must also deal with friend templates. Given:
23508 template <class T> struct S {
23509 template <class U> friend void f() {};
23510 };
23512 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23513 so far as the language is concerned, but that's still
23514 where we get the pattern for the instantiation from. On
23515 other hand, if the definition comes outside the class, say:
23517 template <class T> struct S {
23518 template <class U> friend void f();
23519 };
23520 template <class U> friend void f() {}
23522 we don't need to look any further. That's what the check for
23523 DECL_INITIAL is for. */
23527 {
23528 /* The present template, TD, should not be a definition. If it
23529 were a definition, we should be using it! Note that we
23530 cannot restructure the loop to just keep going until we find
23531 a template with a definition, since that might go too far if
23532 a specialization was declared, but not defined. */
23534 /* Fetch the more general template. */
23536 }
23539 }
23541 /* Returns true if we need to instantiate this template instance even if we
23542 know we aren't going to emit it. */
23544 bool
23546 {
23547 /* We always instantiate inline functions so that we can inline them. An
23548 explicit instantiation declaration prohibits implicit instantiation of
23549 non-inline functions. With high levels of optimization, we would
23550 normally inline non-inline functions -- but we're not allowed to do
23551 that for "extern template" functions. Therefore, we check
23552 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23556 /* And we need to instantiate static data members so that
23557 their initializers are available in integral constant
23558 expressions. */
23561 }
23563 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23564 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23565 error, true otherwise. */
23567 bool
23569 {
23572 /* Don't instantiate a noexcept-specification from template context. */
23588 {
23594 {
23595 /* If hash_set::add returns true, the element was already there. */
23600 fn);
23602 }
23604 {
23619 }
23620 else
23630 }
23633 {
23636 else
23638 }
23641 }
23643 /* We're starting to process the function INST, an instantiation of PATTERN;
23644 add their parameters to local_specializations. */
23646 static void
23648 {
23652 {
23656 }
23658 {
23660 {
23663 }
23664 else
23665 {
23666 /* Register the (value) argument pack as a specialization of
23667 TMPL_PARM, then move on. */
23670 }
23671 }
23673 }
23675 /* Produce the definition of D, a _DECL generated from a template. If
23676 DEFER_OK is true, then we don't have to actually do the
23677 instantiation now; we just have to do it sometime. Normally it is
23678 an error if this is an explicit instantiation but D is undefined.
23679 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23680 instantiated class template. */
23682 tree
23684 {
23686 tree gen_args;
23687 tree args;
23688 tree td;
23689 tree code_pattern;
23690 tree spec;
23691 tree gen_tmpl;
23699 /* This function should only be used to instantiate templates for
23700 functions and static member variables. */
23703 /* A concept is never instantiated. */
23706 /* Variables are never deferred; if instantiation is required, they
23707 are instantiated right away. That allows for better code in the
23708 case that an expression refers to the value of the variable --
23709 if the variable has a constant value the referring expression can
23710 take advantage of that fact. */
23714 /* Don't instantiate cloned functions. Instead, instantiate the
23715 functions they cloned. */
23723 /* D has already been instantiated or explicitly specialized, so
23724 there's nothing for us to do here.
23726 It might seem reasonable to check whether or not D is an explicit
23727 instantiation, and, if so, stop here. But when an explicit
23728 instantiation is deferred until the end of the compilation,
23729 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23730 the instantiation. */
23733 /* Check to see whether we know that this template will be
23734 instantiated in some other file, as with "extern template"
23735 extension. */
23738 /* In general, we do not instantiate such templates. */
23746 /* We should already have the extra args. */
23749 /* And what's in the hash table should match D. */
23753 /* This needs to happen before any tsubsting. */
23759 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23760 for the instantiation. */
23765 {
23766 /* Look up an explicit specialization, if any. */
23770 {
23773 }
23774 }
23778 /* We should never be trying to instantiate a member of a class
23779 template or partial specialization. */
23784 /* In the case of a friend template whose definition is provided
23785 outside the class, we may have too many arguments. Drop the
23786 ones we don't need. The same is true for specializations. */
23787 args = get_innermost_template_args
23791 {
23797 }
23798 else
23799 {
23804 else
23806 }
23808 /* We may be in the middle of deferred access check. Disable it now. */
23811 /* Unless an explicit instantiation directive has already determined
23812 the linkage of D, remember that a definition is available for
23813 this entity. */
23823 /* If D is a member of an explicitly instantiated class template,
23824 and no definition is available, treat it like an implicit
23825 instantiation. */
23828 {
23829 /* Leave linkage flags alone on instantiations with anonymous
23830 visibility. */
23832 {
23835 }
23837 }
23839 /* Defer all other templates, unless we have been explicitly
23840 forbidden from doing so. */
23842 template. */
23843 ! pattern_defined
23844 /* If it's OK to postpone instantiation, do so. */
23845 || defer_ok
23846 /* If this is a static data member that will be defined
23847 elsewhere, we don't want to instantiate the entire data
23848 member, but we do want to instantiate the initializer so that
23849 we can substitute that elsewhere. */
23851 /* Handle here a deleted function too, avoid generating
23852 its body (c++/61080). */
23854 {
23855 /* The definition of the static data member is now required so
23856 we must substitute the initializer. */
23860 {
23861 tree ns;
23862 tree init;
23871 args,
23874 /* If instantiating the initializer involved instantiating this
23875 again, don't call cp_finish_decl twice. */
23877 {
23878 /* Make sure the initializer is still constant, in case of
23879 circular dependency (template/instantiate6.C). */
23880 const_init
23884 LOOKUP_ONLYCONVERTING);
23885 }
23889 }
23891 /* We restore the source position here because it's used by
23892 add_pending_template. */
23898 /* [temp.explicit]
23900 The definition of a non-exported function template, a
23901 non-exported member function template, or a non-exported
23902 member function or static data member of a class template
23903 shall be present in every translation unit in which it is
23904 explicitly instantiated. */
23908 /* If we're in unevaluated context, we just wanted to get the
23909 constant value; this isn't an odr use, so don't queue
23910 a full instantiation. */
23913 /* ??? Historically, we have instantiated inline functions, even
23914 when marked as "extern template". */
23918 }
23919 /* Tell the repository that D is available in this translation unit
23920 -- and see if it is supposed to be instantiated here. */
23922 {
23923 /* In a PCH file, despite the fact that the repository hasn't
23924 requested instantiation in the PCH it is still possible that
23925 an instantiation will be required in a file that includes the
23926 PCH. */
23929 /* Instantiate inline functions so that the inliner can do its
23930 job, even though we'll not be emitting a copy of this
23931 function. */
23934 }
23937 tree fn_context;
23940 /* tsubst_lambda_expr resolved any references to enclosing functions. */
23951 else
23952 {
23957 }
23959 /* Mark D as instantiated so that recursive calls to
23960 instantiate_decl do not try to instantiate it again. */
23963 /* Regenerate the declaration in case the template has been modified
23964 by a subsequent redeclaration. */
23967 /* We already set the file and line above. Reset them now in case
23968 they changed as a result of calling regenerate_decl_from_template. */
23972 {
23973 tree init;
23976 /* Clear out DECL_RTL; whatever was there before may not be right
23977 since we've reset the type of the declaration. */
23981 /* The initializer is placed in DECL_INITIAL by
23982 regenerate_decl_from_template so we don't need to
23983 push/pop_access_scope again here. Pull it out so that
23984 cp_finish_decl can process it. */
23989 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23990 initializer. That function will defer actual emission until
23991 we have a chance to determine linkage. */
23994 /* Enter the scope of D so that access-checking works correctly. */
24007 }
24011 {
24012 /* Set up the list of local specializations. */
24016 /* Set up context. */
24020 else
24023 /* Some typedefs referenced from within the template code need to be
24024 access checked at template instantiation time, i.e now. These
24025 types were added to the template at parsing time. Let's get those
24026 and perform the access checks then. */
24028 args);
24030 /* Create substitution entries for the parameters. */
24033 /* Substitute into the body of the function. */
24037 else
24038 {
24043 /* Set the current input_location to the end of the function
24044 so that finish_function knows where we are. */
24045 input_location
24048 /* Remember if we saw an infinite loop in the template. */
24049 current_function_infinite_loop
24051 }
24053 /* Finish the function. */
24057 else
24058 {
24061 }
24065 }
24067 /* We're not deferring instantiation any more. */
24072 else
24078 out:
24087 }
24089 /* Run through the list of templates that we wish we could
24090 instantiate, and instantiate any we can. RETRIES is the
24091 number of times we retry pending template instantiation. */
24093 void
24095 {
24099 /* Instantiating templates may trigger vtable generation. This in turn
24100 may require further template instantiations. We place a limit here
24101 to avoid infinite loop. */
24103 {
24107 "template instantiation depth exceeds maximum of %d"
24108 " instantiating %q+D, possibly from virtual table generation"
24112 /* Pretend that we defined it. */
24115 }
24117 do
24118 {
24123 {
24128 {
24130 {
24145 }
24148 }
24149 else
24150 {
24153 {
24154 instantiation
24160 }
24164 }
24167 {
24168 /* If INSTANTIATION has been instantiated, then we don't
24169 need to consider it again in the future. */
24174 }
24175 else
24176 {
24179 }
24182 }
24184 }
24188 }
24190 /* Substitute ARGVEC into T, which is a list of initializers for
24191 either base class or a non-static data member. The TREE_PURPOSEs
24192 are DECLs, and the TREE_VALUEs are the initializer values. Used by
24193 instantiate_decl. */
24195 static tree
24197 {
24202 {
24203 tree decl;
24204 tree init;
24210 {
24211 tree expr;
24212 tree arg;
24214 /* Expand the base class expansion type into separate base
24215 classes. */
24217 tf_warning_or_error,
24218 NULL_TREE);
24222 /* We'll be building separate TREE_LISTs of arguments for
24223 each base. */
24229 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
24230 expand each argument in the TREE_VALUE of t. */
24237 /* VOID_TYPE_NODE is used to indicate
24238 value-initialization. */
24239 {
24242 }
24243 else
24244 {
24245 /* Substitute parameter packs into each argument in the
24246 TREE_LIST. */
24249 {
24250 tree expanded_exprs;
24252 /* Expand the argument. */
24254 expanded_exprs
24256 tf_warning_or_error,
24257 NULL_TREE);
24261 /* Prepend each of the expanded expressions to the
24262 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
24264 {
24269 }
24270 }
24273 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
24274 since we built them backwards. */
24276 {
24279 }
24280 }
24281 }
24284 {
24286 {
24290 }
24291 else
24292 {
24293 tree tmp;
24308 /* If we had an initializer but it instantiated to nothing,
24309 value-initialize the object. This will only occur when
24310 the initializer was a pack expansion where the parameter
24311 packs used in that expansion were of length zero. */
24314 }
24318 {
24320 decl);
24322 }
24323 /* Look for a target constructor. */
24327 {
24330 {
24334 }
24336 }
24339 {
24343 }
24344 }
24345 }
24347 }
24349 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
24351 static void
24353 {
24358 else
24360 }
24362 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
24363 is the instantiation (which should have been created with
24364 start_enum) and ARGS are the template arguments to use. */
24366 static void
24368 {
24369 tree e;
24375 {
24376 tree value;
24377 tree decl;
24380 /* Note that in a template enum, the TREE_VALUE is the
24381 CONST_DECL, not the corresponding INTEGER_CST. */
24386 /* Give this enumeration constant the correct access. */
24389 /* Actually build the enumerator itself. Here we're assuming that
24390 enumerators can't have dependent attributes. */
24393 }
24403 }
24405 /* DECL is a FUNCTION_DECL that is a template specialization. Return
24406 its type -- but without substituting the innermost set of template
24407 arguments. So, innermost set of template parameters will appear in
24408 the type. */
24410 tree
24412 {
24413 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
24415 }
24417 /* Return truthvalue if we're processing a template different from
24418 the last one involved in diagnostics. */
24419 bool
24421 {
24423 }
24425 /* Remember current template involved in diagnostics. */
24426 void
24428 {
24430 }
24434 {
24436 }
24438 /* Return TRUE if current_function_decl is being instantiated, false
24439 otherwise. */
24441 bool
24443 {
24447 }
24449 /* [temp.param] Check that template non-type parm TYPE is of an allowable
24450 type. Return false for ok, true for disallowed. Issue error and
24451 inform messages under control of COMPLAIN. */
24453 static bool
24455 {
24473 /* A bound template template parm could later be instantiated to have a valid
24474 nontype parm type via an alias template. */
24480 {
24483 else
24485 type);
24486 }
24488 }
24490 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
24491 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
24493 static bool
24495 {
24496 tree scope;
24498 /* [temp.dep.type]
24500 A type is dependent if it is:
24502 -- a template parameter. Template template parameters are types
24503 for us (since TYPE_P holds true for them) so we handle
24504 them here. */
24508 /* -- a qualified-id with a nested-name-specifier which contains a
24509 class-name that names a dependent type or whose unqualified-id
24510 names a dependent type. */
24514 /* An alias template specialization can be dependent even if the
24515 resulting type is not. */
24519 /* -- a cv-qualified type where the cv-unqualified type is
24520 dependent.
24521 No code is necessary for this bullet; the code below handles
24522 cv-qualified types, and we don't want to strip aliases with
24523 TYPE_MAIN_VARIANT because of DR 1558. */
24524 /* -- a compound type constructed from any dependent type. */
24533 {
24534 tree arg_type;
24539 arg_type;
24544 /* A value-dependent noexcept-specifier makes the type dependent. */
24547 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24548 affect overload resolution and treating it as dependent breaks
24549 things. */
24554 }
24555 /* -- an array type constructed from any dependent type or whose
24556 size is specified by a constant expression that is
24557 value-dependent.
24559 We checked for type- and value-dependence of the bounds in
24560 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24562 {
24567 }
24569 /* -- a template-id in which either the template name is a template
24570 parameter ... */
24573 /* ... or any of the template arguments is a dependent type or
24574 an expression that is type-dependent or value-dependent. */
24576 && (any_dependent_template_arguments_p
24580 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24581 dependent; if the argument of the `typeof' expression is not
24582 type-dependent, then it should already been have resolved. */
24588 /* A template argument pack is dependent if any of its packed
24589 arguments are. */
24591 {
24597 }
24599 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24600 be template parameters. */
24607 /* The standard does not specifically mention types that are local
24608 to template functions or local classes, but they should be
24609 considered dependent too. For example:
24611 template <int I> void f() {
24612 enum E { a = I };
24613 S<sizeof (E)> s;
24614 }
24616 The size of `E' cannot be known until the value of `I' has been
24617 determined. Therefore, `E' must be considered dependent. */
24621 /* Don't use type_dependent_expression_p here, as it can lead
24622 to infinite recursion trying to determine whether a lambda
24623 nested in a lambda is dependent (c++/47687). */
24627 && (any_dependent_template_arguments_p
24631 /* Other types are non-dependent. */
24633 }
24635 /* Returns TRUE if TYPE is dependent, in the sense of
24636 [temp.dep.type]. Note that a NULL type is considered dependent. */
24638 bool
24640 {
24641 /* If there are no template parameters in scope, then there can't be
24642 any dependent types. */
24644 {
24645 /* If we are not processing a template, then nobody should be
24646 providing us with a dependent type. */
24650 }
24652 /* If the type is NULL, we have not computed a type for the entity
24653 in question; in that case, the type is dependent. */
24657 /* Erroneous types can be considered non-dependent. */
24661 /* Getting here with global_type_node means we improperly called this
24662 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24665 /* If we have not already computed the appropriate value for TYPE,
24666 do so now. */
24668 {
24671 }
24674 }
24676 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24677 lookup. In other words, a dependent type that is not the current
24678 instantiation. */
24680 bool
24682 {
24685 }
24687 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24688 an unknown base of 'this' (and is therefore instantiation-dependent). */
24690 static bool
24692 {
24709 }
24711 /* T is a SCOPE_REF; return whether we need to consider it
24712 instantiation-dependent so that we can check access at instantiation
24713 time even though we know which member it resolves to. */
24715 static bool
24717 {
24724 else
24726 }
24728 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24729 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24730 expression. */
24732 /* Note that this predicate is not appropriate for general expressions;
24733 only constant expressions (that satisfy potential_constant_expression)
24734 can be tested for value dependence. */
24736 bool
24738 {
24742 /* A type-dependent expression is also value-dependent. */
24747 {
24749 /* A dependent member function of the current instantiation. */
24753 /* A dependent member function of the current instantiation. */
24760 /* A name that has not been looked up -- must be dependent. */
24764 /* A non-type template parm. */
24768 /* A non-type template parm. */
24774 /* A constant with literal type and is initialized
24775 with an expression that is value-dependent. */
24777 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24781 {
24785 }
24794 /* These expressions are value-dependent if the type to which
24795 the cast occurs is dependent or the expression being casted
24796 is value-dependent. */
24797 {
24803 /* A functional cast has a list of operands. */
24806 {
24807 /* If there are no operands, it must be an expression such
24808 as "int()". This should not happen for aggregate types
24809 because it would form non-constant expressions. */
24814 }
24820 }
24825 /* FALLTHRU */
24828 /* A `sizeof' expression is value-dependent if the operand is
24829 type-dependent or is a pack expansion. */
24838 /* An 'encode' expression is value-dependent if the operand is
24839 type-dependent. */
24848 /* All instantiation-dependent expressions should also be considered
24849 value-dependent. */
24857 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24858 is value-dependent. */
24859 {
24868 }
24871 {
24888 }
24899 {
24903 }
24906 /* Treat all requires-expressions as value-dependent so
24907 we don't try to fold them. */
24914 {
24921 {
24923 /* In a call to a constexpr member function, look through the
24924 implicit ADDR_EXPR on the object argument so that it doesn't
24925 cause the call to be considered value-dependent. We also
24926 look through it in potential_constant_expression. */
24933 }
24935 }
24941 {
24943 tree val;
24950 }
24953 /* Treat a GNU statement expression as dependent to avoid crashing
24954 under instantiate_non_dependent_expr; it can't be constant. */
24958 /* A constant expression is value-dependent if any subexpression is
24959 value-dependent. */
24961 {
24968 {
24972 {
24975 /* In some cases, some of the operands may be missing.
24976 (For example, in the case of PREDECREMENT_EXPR, the
24977 amount to increment by may be missing.) That doesn't
24978 make the expression dependent. */
24981 }
24982 }
24986 }
24988 }
24990 /* The expression is not value-dependent. */
24992 }
24994 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24995 [temp.dep.expr]. Note that an expression with no type is
24996 considered dependent. Other parts of the compiler arrange for an
24997 expression with type-dependent subexpressions to have no type, so
24998 this function doesn't have to be fully recursive. */
25000 bool
25002 {
25011 /* An unresolved name is always dependent. */
25017 /* A fold expression is type-dependent. */
25024 /* Some expression forms are never type-dependent. */
25038 /* The types of these expressions depends only on the type to which
25039 the cast occurs. */
25048 /* The types of these expressions depends only on the type created
25049 by the expression. */
25052 {
25053 /* For NEW_EXPR tree nodes created inside a template, either
25054 the object type itself or a TREE_LIST may appear as the
25055 operand 1. */
25058 /* This is an array type. We need to check array dimensions
25059 as well. */
25061 || value_dependent_expression_p
25063 else
25065 }
25068 {
25072 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
25073 contains an identifier associated by name lookup with one or more
25074 declarations declared with a dependent type, or...a
25075 nested-name-specifier or qualified-id that names a member of an
25076 unknown specialization. */
25079 }
25089 {
25090 tree elt;
25094 {
25097 }
25099 }
25101 /* A static data member of the current instantiation with incomplete
25102 array type is type-dependent, as the definition and specializations
25103 can have different bounds. */
25110 /* An array of unknown bound depending on a variadic parameter, eg:
25112 template<typename... Args>
25113 void foo (Args... args)
25114 {
25115 int arr[] = { args... };
25116 }
25118 template<int... vals>
25119 void bar ()
25120 {
25121 int arr[] = { vals... };
25122 }
25124 If the array has no length and has an initializer, it must be that
25125 we couldn't determine its length in cp_complete_array_type because
25126 it is dependent. */
25134 /* A function or variable template-id is type-dependent if it has any
25135 dependent template arguments. */
25139 {
25140 /* Consider the innermost template arguments, since those are the ones
25141 that come from the template-id; the template arguments for the
25142 enclosing class do not make it type-dependent unless they are used in
25143 the type of the decl. */
25145 && (any_dependent_template_arguments_p
25148 }
25150 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
25151 type-dependent. Checking this is important for functions with auto return
25152 type, which looks like a dependent type. */
25161 {
25165 }
25167 /* Always dependent, on the number of arguments if nothing else. */
25172 {
25177 {
25183 }
25184 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
25189 {
25194 }
25197 {
25204 }
25214 }
25218 /* Dependent type attributes might not have made it from the decl to
25219 the type yet. */
25225 }
25227 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
25228 type-dependent if the expression refers to a member of the current
25229 instantiation and the type of the referenced member is dependent, or the
25230 class member access expression refers to a member of an unknown
25231 specialization.
25233 This function returns true if the OBJECT in such a class member access
25234 expression is of an unknown specialization. */
25236 bool
25238 {
25239 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
25240 dependent. */
25245 }
25247 /* walk_tree callback function for instantiation_dependent_expression_p,
25248 below. Returns non-zero if a dependent subexpression is found. */
25250 static tree
25253 {
25255 {
25256 /* We don't have to worry about decltype currently because decltype
25257 of an instantiation-dependent expr is a dependent type. This
25258 might change depending on the resolution of DR 1172. */
25261 }
25264 {
25265 /* Don't treat an argument list as dependent just because it has no
25266 TREE_TYPE. */
25275 /* Handle expressions with type operands. */
25280 {
25285 {
25288 else
25289 {
25292 }
25293 }
25295 }
25299 /* In a template, finish_class_member_access_expr creates a
25300 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
25301 type-dependent, so that we can check access control at
25302 instantiation time (PR 42277). See also Core issue 1273. */
25309 else
25312 /* Treat statement-expressions as dependent. */
25316 /* Treat requires-expressions as dependent. */
25321 /* Treat calls to function concepts as dependent. */
25327 /* And variable concepts. */
25334 }
25338 else
25340 }
25342 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
25343 sense defined by the ABI:
25345 "An expression is instantiation-dependent if it is type-dependent
25346 or value-dependent, or it has a subexpression that is type-dependent
25347 or value-dependent."
25349 Except don't actually check value-dependence for unevaluated expressions,
25350 because in sizeof(i) we don't care about the value of i. Checking
25351 type-dependence will in turn check value-dependence of array bounds/template
25352 arguments as needed. */
25354 bool
25356 {
25357 tree result;
25368 }
25370 /* As above, but also check value-dependence of the expression as a whole. */
25372 bool
25374 {
25377 }
25379 /* Like type_dependent_expression_p, but it also works while not processing
25380 a template definition, i.e. during substitution or mangling. */
25382 bool
25384 {
25390 }
25392 /* Returns TRUE if ARGS contains a type-dependent expression. */
25394 bool
25396 {
25398 tree arg;
25401 {
25404 }
25406 }
25408 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25409 expressions) contains any type-dependent expressions. */
25411 bool
25413 {
25419 }
25421 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25422 expressions) contains any value-dependent expressions. */
25424 bool
25426 {
25432 }
25434 /* Returns TRUE if the ARG (a template argument) is dependent. */
25436 bool
25438 {
25442 /* Assume a template argument that was wrongly written by the user
25443 is dependent. This is consistent with what
25444 any_dependent_template_arguments_p [that calls this function]
25445 does. */
25455 {
25458 /* A member template of a dependent class is not necessarily
25459 type-dependent, but it is a dependent template argument because it
25460 will be a member of an unknown specialization to that template. */
25463 }
25465 {
25469 {
25472 }
25475 }
25478 else
25481 }
25483 /* Returns true if ARGS (a collection of template arguments) contains
25484 any types that require structural equality testing. */
25486 bool
25488 {
25498 {
25501 {
25507 {
25508 /* Look inside the argument pack. */
25511 }
25514 {
25527 }
25528 }
25529 }
25532 }
25534 /* Returns true if ARGS (a collection of template arguments) contains
25535 any dependent arguments. */
25537 bool
25539 {
25549 {
25554 }
25557 }
25559 /* Returns true if ARGS contains any errors. */
25561 bool
25563 {
25571 {
25574 else
25576 }
25582 {
25587 }
25590 }
25592 /* Returns TRUE if the template TMPL is type-dependent. */
25594 bool
25596 {
25598 {
25603 }
25605 /* Template template parameters are dependent. */
25609 /* So are names that have not been looked up. */
25613 }
25615 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25617 bool
25619 {
25622 }
25624 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25625 are dependent. */
25627 bool
25629 {
25636 {
25658 {
25662 }
25666 {
25670 {
25675 }
25676 }
25677 }
25680 }
25682 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25683 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25684 no such TYPE can be found. Note that this function peers inside
25685 uninstantiated templates and therefore should be used only in
25686 extremely limited situations. ONLY_CURRENT_P restricts this
25687 peering to the currently open classes hierarchy (which is required
25688 when comparing types). */
25690 tree
25692 {
25693 tree scope;
25694 tree name;
25695 tree decl;
25697 tree pushed_scope;
25698 tree result;
25703 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25706 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25707 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25708 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25709 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25710 identifier of the TYPENAME_TYPE anymore.
25711 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25712 TYPENAME_TYPE instead, we avoid messing up with a possible
25713 typedef variant case. */
25716 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25717 it first before we can figure out what NAME refers to. */
25719 {
25721 /* Given a class template A with a dependent base with nested type C,
25722 typedef typename A::C::C C will land us here, as trying to resolve
25723 the initial A::C leads to the local C typedef, which leads back to
25724 A::C::C. So we break the recursion now. */
25726 else
25728 }
25729 /* If we don't know what SCOPE refers to, then we cannot resolve the
25730 TYPENAME_TYPE. */
25733 /* If this is a typedef, we don't want to look inside (c++/11987). */
25736 /* If SCOPE isn't the template itself, it will not have a valid
25737 TYPE_FIELDS list. */
25739 /* scope is either the template itself or a compatible instantiation
25740 like X<T>, so look up the name in the original template. */
25742 /* If scope has no fields, it can't be a current instantiation. Check this
25743 before currently_open_class to avoid infinite recursion (71515). */
25746 /* If the SCOPE is not the current instantiation, there's no reason
25747 to look inside it. */
25750 /* Enter the SCOPE so that name lookup will be resolved as if we
25751 were in the class definition. In particular, SCOPE will no
25752 longer be considered a dependent type. */
25754 /* Look up the declaration. */
25756 tf_warning_or_error);
25760 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25761 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25767 {
25771 }
25774 {
25775 /* Obtain the template and the arguments. */
25778 {
25779 /* We get here with a plain identifier because a previous tentative
25780 parse of the nested-name-specifier as part of a ptr-operator saw
25781 ::template X<A>. The use of ::template is necessary in a
25782 ptr-operator, but wrong in a declarator-id.
25784 [temp.names]: In a qualified-id of a declarator-id, the keyword
25785 template shall not appear at the top level. */
25789 }
25791 /* Instantiate the template. */
25797 }
25799 /* Leave the SCOPE. */
25803 /* If we failed to resolve it, return the original typename. */
25807 /* If lookup found a typename type, resolve that too. */
25809 {
25810 /* Ill-formed programs can cause infinite recursion here, so we
25811 must catch that. */
25815 }
25817 /* Qualify the resulting type. */
25823 }
25825 /* EXPR is an expression which is not type-dependent. Return a proxy
25826 for EXPR that can be used to compute the types of larger
25827 expressions containing EXPR. */
25829 tree
25831 {
25833 tree inner_expr;
25835 /* When checking, try to get a constant value for all non-dependent
25836 expressions in order to expose bugs in *_dependent_expression_p
25837 and constexpr. This can affect code generation, see PR70704, so
25838 only do this for -fchecking=2. */
25841 /* Don't do this during nsdmi parsing as it can lead to
25842 unexpected recursive instantiations. */
25844 /* Don't do this during concept expansion either and for
25845 the same reason. */
25851 /* Preserve OVERLOADs; the functions must be available to resolve
25852 types. */
25863 /* There is no need to return a proxy for a variable or enumerator. */
25866 /* Preserve string constants; conversions from string constants to
25867 "char *" are allowed, even though normally a "const char *"
25868 cannot be used to initialize a "char *". */
25871 /* Preserve void and arithmetic constants, as an optimization -- there is no
25872 reason to create a new node. */
25877 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25878 There is at least one place where we want to know that a
25879 particular expression is a throw-expression: when checking a ?:
25880 expression, there are special rules if the second or third
25881 argument is a throw-expression. */
25885 /* Don't wrap an initializer list, we need to be able to look inside. */
25889 /* Don't wrap a dummy object, we need to be able to test for it. */
25908 /* If the type is unknown, it can't really be non-dependent */
25911 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25914 }
25916 /* ARGS is a vector of expressions as arguments to a function call.
25917 Replace the arguments with equivalent non-dependent expressions.
25918 This modifies ARGS in place. */
25920 void
25922 {
25924 tree arg;
25927 {
25931 }
25932 }
25934 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25935 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25936 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25938 static tree
25940 {
25954 }
25956 tree
25958 {
25960 }
25962 tree
25964 {
25966 }
25968 /* Return a C++17 deduction placeholder for class template TMPL. */
25970 tree
25972 {
25976 }
25978 /* True iff T is a C++17 class template deduction placeholder. */
25980 bool
25982 {
25984 }
25986 /* Make a "constrained auto" type-specifier. This is an
25987 auto type with constraints that must be associated after
25988 deduction. The constraint is formed from the given
25989 CONC and its optional sequence of arguments, which are
25990 non-null if written as partial-concept-id. */
25992 tree
25994 {
25997 /* Build the constraint. */
26005 /* Our canonical type depends on the constraint. */
26008 /* Attach the constraint to the type declaration. */
26011 }
26013 /* Given type ARG, return std::initializer_list<ARG>. */
26015 static tree
26017 {
26021 {
26025 "deducing from brace-enclosed initializer list"
26029 }
26035 }
26037 /* Replace auto in TYPE with std::initializer_list<auto>. */
26039 static tree
26041 {
26048 }
26050 /* Hash traits for hashing possibly constrained 'auto'
26051 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
26054 {
26057 };
26059 /* Hash the 'auto' T. */
26061 inline hashval_t
26063 {
26065 /* Matching constrained-type-specifiers denote the same template
26066 parameter, so hash the constraint. */
26068 else
26069 /* But unconstrained autos are all separate, so just hash the pointer. */
26071 }
26073 /* Compare two 'auto's. */
26077 {
26084 /* Two unconstrained autos are distinct. */
26089 }
26091 /* for_each_template_parm callback for extract_autos: if t is a (possibly
26092 constrained) auto, add it to the vector. */
26094 static int
26096 {
26099 {
26100 /* All the autos were built with index 0; fix that up now. */
26104 /* If this is a repeated constrained-type-specifier, use the index we
26105 chose before. */
26107 else
26108 {
26109 /* Otherwise this is new, so use the current count. */
26112 }
26114 }
26116 /* Always keep walking. */
26118 }
26120 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
26121 says they can appear anywhere in the type. */
26123 static tree
26125 {
26134 {
26139 }
26142 }
26144 /* The stem for deduction guide names. */
26147 /* Return the name for a deduction guide for class template TMPL. */
26149 tree
26151 {
26162 }
26164 /* True if NAME is the name of a deduction guide. */
26166 bool
26168 {
26173 }
26175 /* True if FN is a deduction guide. */
26177 bool
26179 {
26184 }
26186 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
26188 bool
26190 {
26197 }
26199 /* True if FN is a guide generated from a constructor template. */
26201 bool
26203 {
26211 }
26213 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
26214 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
26215 template parameter types. Note that the handling of template template
26216 parameters relies on current_template_parms being set appropriately for the
26217 new template. */
26219 static tree
26222 {
26228 tree newtype;
26231 {
26238 }
26239 else
26240 {
26243 {
26244 // Substitute once to fix references to other template parameters.
26247 // Now substitute again to reduce the level of the auto.
26250 }
26251 else
26254 }
26256 tree newdecl
26261 tree newidx;
26264 {
26274 {
26279 // First create a copy (ttargs) of tsubst_args with an
26280 // additional level for the template template parameter's own
26281 // template parameters (ttparms).
26282 tree ttparms = (INNERMOST_TEMPLATE_PARMS
26290 // Substitute ttargs into ttparms to fix references to
26291 // other template parameters.
26294 // Now substitute again with args based on tparms, to reduce
26295 // the level of the ttparms.
26298 complain);
26299 // Finally, tack the adjusted parms onto tparms.
26301 current_template_parms);
26303 }
26304 }
26305 else
26306 {
26308 tree newconst
26320 }
26323 }
26325 /* Returns a C++17 class deduction guide template based on the constructor
26326 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
26327 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
26329 static tree
26331 {
26335 location_t loc;
26339 {
26343 {
26346 }
26347 else
26357 }
26358 else
26359 {
26363 fn_tmpl
26373 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
26374 fully specialized args for the enclosing class. Strip those off, as
26375 the deduction guide won't have those template parameters. */
26378 /* Discard the 'this' parameter. */
26386 {
26389 /* For a member template constructor, we need to flatten the two
26390 template parameter lists into one, and then adjust the function
26391 signature accordingly. This gets...complicated. */
26394 /* For a member template we should have two levels of parms/args, one
26395 for the class and one for the constructor. We stripped
26396 specialized args for further enclosing classes above. */
26400 /* Template args for translating references to the two-level template
26401 parameters into references to the one-level template parameters we
26402 are creating. */
26407 /* Template parms for the constructor template. */
26410 /* Template parms for the class template. */
26414 /* Template parms for the deduction guide start as a copy of the
26415 template parms for the class. We set current_template_parms for
26416 lookup_template_class_1. */
26422 /* Now we need to rewrite the constructor parms to append them to the
26423 class parms. */
26425 {
26442 }
26444 /* Now we have a final set of template parms to substitute into the
26445 function signature. */
26454 }
26459 }
26462 {
26463 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
26467 }
26471 FUNCTION_DECL,
26488 }
26490 /* Deduce template arguments for the class template placeholder PTYPE for
26491 template TMPL based on the initializer INIT, and return the resulting
26492 type. */
26494 static tree
26496 tsubst_flags_t complain)
26497 {
26499 {
26500 /* We should have handled this in the caller. */
26506 }
26517 {
26520 {
26521 /* As an exception, the first phase in 16.3.1.7 (considering the
26522 initializer list as a single argument) is omitted if the
26523 initializer list consists of a single expression of type cv U,
26524 where U is a specialization of C or a class derived from a
26525 specialization of C. */
26536 }
26539 else
26541 }
26542 else
26553 /* Prune explicit deduction guides in copy-initialization context. */
26555 {
26561 {
26562 /* Found a nonconverting guide, prune the candidates. */
26569 }
26570 }
26575 {
26578 }
26581 // FIXME cache artificial deduction guides
26583 {
26584 /* Skip inherited constructors. */
26594 else
26598 }
26602 /* If this is list-initialization and the class has a list constructor, first
26603 try deducing from the list as a single argument, as [over.match.list]. */
26607 {
26611 }
26613 {
26619 {
26620 /* That didn't work, now try treating the list as a sequence of
26621 arguments. */
26624 }
26625 }
26627 /* Maybe generate an implicit deduction guide. */
26629 {
26633 /* Generate a copy guide. */
26636 /* Generate a default guide. */
26640 {
26645 }
26646 }
26649 {
26651 " of %qT, as it has no non-explicit deduction guides or "
26654 }
26656 {
26660 }
26663 {
26667 }
26670 {
26680 }
26685 }
26687 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26688 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26689 The CONTEXT determines the context in which auto deduction is performed
26690 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26691 OUTER_TARGS are used during template argument deduction
26692 (context == adc_unify) to properly substitute the result, and is ignored
26693 in other contexts.
26695 For partial-concept-ids, extra args may be appended to the list of deduced
26696 template arguments prior to determining constraint satisfaction. */
26698 tree
26702 {
26703 tree targs;
26710 /* Defining a subset of type-dependent expressions that we can deduce
26711 from ahead of time isn't worth the trouble. */
26714 /* Similarly, we can't deduce from another undeduced decl. */
26719 /* C++17 class template argument deduction. */
26723 /* Nothing we can do with this, even in deduction context. */
26726 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26727 with either a new invented type template parameter U or, if the
26728 initializer is a braced-init-list (8.5.4), with
26729 std::initializer_list<U>. */
26731 {
26736 else
26737 {
26739 {
26743 "for deduction to %<std::initializer_list%>, use copy-"
26745 }
26747 }
26748 }
26759 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26760 and initializer has array type, deduce cv-qualified array type. */
26762 complain);
26764 {
26773 {
26777 }
26778 }
26779 else
26780 {
26782 tree tparms;
26786 else
26787 {
26791 }
26798 {
26800 /* Try again at instantiation time. */
26804 /* If type is error_mark_node a diagnostic must have been
26805 emitted by now. Also, having a mention to '<type error>'
26806 in the diagnostic is not really useful to the user. */
26807 {
26811 else
26816 }
26818 }
26819 }
26821 /* Check any placeholder constraints against the deduced type. */
26824 {
26825 /* Use the deduced type to check the associated constraints. If we
26826 have a partial-concept-id, rebuild the argument list so that
26827 we check using the extra arguments. */
26831 {
26834 }
26835 else
26838 {
26840 {
26842 {
26860 }
26862 }
26864 }
26865 }
26871 }
26873 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26874 result. */
26876 tree
26878 {
26880 {
26886 /* In an abbreviated function template we didn't know we were dealing
26887 with a function template when we saw the auto return type, so update
26888 it to have the correct level. */
26890 }
26892 }
26894 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26895 'decltype(auto)' or a deduced class template. */
26897 bool
26899 {
26905 else
26907 }
26909 /* for_each_template_parm callback for type_uses_auto. */
26911 int
26913 {
26915 }
26917 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26918 a use of `auto'. Returns NULL_TREE otherwise. */
26920 tree
26922 {
26926 {
26927 /* The Concepts TS allows multiple autos in one type-specifier; just
26928 return the first one we find, do_auto_deduction will collect all of
26929 them. */
26933 else
26935 }
26936 else
26938 }
26940 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
26941 concepts are enabled, auto is acceptable in template arguments, but
26942 only when TEMPL identifies a template class. Return TRUE if any
26943 such errors were reported. */
26945 bool
26947 {
26948 /* If there were previous errors, nevermind. */
26952 /* If TMPL is an identifier, we're parsing and we can't tell yet
26953 whether TMPL is supposed to be a type, a function or a variable.
26954 We'll only be able to tell during template substitution, so we
26955 expect to be called again then. If concepts are enabled and we
26956 know we have a type, we're ok. */
26964 /* Quickly search for any occurrences of auto; usually there won't
26965 be any, and then we'll avoid allocating the vector. */
26973 {
26978 }
26981 }
26983 /* For a given template T, return the vector of typedefs referenced
26984 in T for which access check is needed at T instantiation time.
26985 T is either a FUNCTION_DECL or a RECORD_TYPE.
26986 Those typedefs were added to T by the function
26987 append_type_to_template_for_access_check. */
26991 {
26992 tree ti;
27003 {
27008 }
27011 }
27013 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
27014 tied to T. That list of typedefs will be access checked at
27015 T instantiation time.
27016 T is either a FUNCTION_DECL or a RECORD_TYPE.
27017 TYPE_DECL is a TYPE_DECL node representing a typedef.
27018 SCOPE is the scope through which TYPE_DECL is accessed.
27019 LOCATION is the location of the usage point of TYPE_DECL.
27021 This function is a subroutine of
27022 append_type_to_template_for_access_check. */
27024 static void
27026 tree type_decl,
27027 tree scope,
27028 location_t location)
27029 {
27030 qualified_typedef_usage_t typedef_usage;
27031 tree ti;
27038 && type_decl
27052 }
27054 /* Append TYPE_DECL to the template TEMPL.
27055 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
27056 At TEMPL instanciation time, TYPE_DECL will be checked to see
27057 if it can be accessed through SCOPE.
27058 LOCATION is the location of the usage point of TYPE_DECL.
27060 e.g. consider the following code snippet:
27062 class C
27063 {
27064 typedef int myint;
27065 };
27067 template<class U> struct S
27068 {
27069 C::myint mi; // <-- usage point of the typedef C::myint
27070 };
27072 S<char> s;
27074 At S<char> instantiation time, we need to check the access of C::myint
27075 In other words, we need to check the access of the myint typedef through
27076 the C scope. For that purpose, this function will add the myint typedef
27077 and the scope C through which its being accessed to a list of typedefs
27078 tied to the template S. That list will be walked at template instantiation
27079 time and access check performed on each typedefs it contains.
27080 Note that this particular code snippet should yield an error because
27081 myint is private to C. */
27083 void
27085 tree type_decl,
27086 tree scope,
27087 location_t location)
27088 {
27094 /* Make sure we don't append the type to the template twice. */
27101 }
27103 /* Convert the generic type parameters in PARM that match the types given in the
27104 range [START_IDX, END_IDX) from the current_template_parms into generic type
27105 packs. */
27107 tree
27109 {
27120 {
27121 /* Create a distinct parameter pack type from the current parm and add it
27122 to the replacement args to tsubst below into the generic function
27123 parameter. */
27138 }
27144 /* If there are more levels then build up the replacement with the outer
27145 template parms. */
27149 replacement);
27152 }
27154 /* Entries in the decl_constraint hash table. */
27156 {
27157 tree decl;
27158 tree ci;
27159 };
27161 /* Hashing function and equality for constraint entries. */
27163 {
27165 {
27167 }
27170 {
27172 }
27173 };
27175 /* A mapping from declarations to constraint information. Note that
27176 both templates and their underlying declarations are mapped to the
27177 same constraint information.
27179 FIXME: This is defined in pt.c because garbage collection
27180 code is not being generated for constraint.cc. */
27184 /* Returns the template constraints of declaration T. If T is not
27185 constrained, return NULL_TREE. Note that T must be non-null. */
27187 tree
27189 {
27200 else
27202 }
27204 /* Associate the given constraint information CI with the declaration
27205 T. If T is a template, then the constraints are associated with
27206 its underlying declaration. Don't build associations if CI is
27207 NULL_TREE. */
27209 void
27211 {
27223 }
27225 /* Remove the associated constraints of the declaration T. */
27227 void
27229 {
27238 }
27240 /* Memoized satisfaction results for declarations. This
27241 maps the pair (constraint_info, arguments) to the result computed
27242 by constraints_satisfied_p. */
27245 {
27246 tree ci;
27247 tree args;
27248 tree result;
27249 };
27251 /* Hashing function and equality for constraint entries. */
27254 {
27256 {
27259 }
27262 {
27264 }
27265 };
27267 /* Memoized satisfaction results for concept checks. */
27270 {
27271 tree tmpl;
27272 tree args;
27273 tree result;
27274 };
27276 /* Hashing function and equality for constraint entries. */
27279 {
27281 {
27283 }
27286 {
27291 }
27292 };
27297 /* Search for a memoized satisfaction result. Returns one of the
27298 truth value nodes if previously memoized, or NULL_TREE otherwise. */
27300 tree
27302 {
27307 else
27309 }
27311 /* Memoize the result of a satisfication test. Returns the saved result. */
27313 tree
27315 {
27322 }
27324 /* Search for a memoized satisfaction result for a concept. */
27326 tree
27328 {
27333 else
27335 }
27337 /* Memoize the result of a concept check. Returns the saved result. */
27339 tree
27341 {
27348 }
27352 /* Returns a prior concept specialization. This returns the substituted
27353 and normalized constraints defined by the concept. */
27355 tree
27357 {
27362 else
27364 }
27366 /* Save a concept expansion for later. */
27368 tree
27370 {
27377 }
27379 static hashval_t
27381 {
27390 }
27392 /* Compare the constraints of two subsumption entries. The LEFT1 and
27393 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
27394 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
27396 static bool
27398 {
27406 }
27408 /* Key/value pair for learning and memoizing subsumption results. This
27409 associates a pair of check constraints (including arguments) with
27410 a boolean value indicating the result. */
27413 {
27414 tree t1;
27415 tree t2;
27417 };
27419 /* Hashing function and equality for constraint entries. */
27422 {
27424 {
27426 }
27429 {
27434 }
27435 };
27439 /* Search for a previously cached subsumption result. */
27443 {
27448 else
27450 }
27452 /* Save a subsumption result. */
27454 bool
27456 {
27463 }
27465 /* Set up the hash table for constraint association. */
27467 void
27469 {
27478 }
27480 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
27481 0..N-1. */
27483 void
27485 {
27488 integer_type_node,
27489 NULL_TREE),
27493 }
27495 /* Set up the hash tables for template instantiations. */
27497 void
27499 {
27505 }
27507 /* Print stats about the template hash tables for -fstats. */
27509 void
27511 {
27520 }
27522 #if CHECKING_P
27526 /* Verify that build_non_dependent_expr () works, for various expressions,
27527 and that location wrappers don't affect the results. */
27529 static void
27531 {
27534 /* Verify constants, without and with location wrappers. */
27551 }
27553 /* Verify that type_dependent_expression_p () works correctly, even
27554 in the presence of location wrapper nodes. */
27556 static void
27558 {
27563 /* If no templates are involved, nothing is type-dependent. */
27569 /* Within a template, an unresolved name is always type-dependent. */
27572 /* Ensure it copes with NULL_TREE and errors. */
27576 /* A USING_DECL in a template should be type-dependent, even if wrapped
27577 with a location wrapper (PR c++/83799). */
27586 }
27588 /* Run all of the selftests within this file. */
27590 void
27592 {
27595 }