| blob | 180dfd6861c1c910e01cb12b2291d3be880da056 |
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);
2538 }
2540 /* Return the number of template headers we expect to see for a definition
2541 or specialization of CTYPE or one of its non-template members. */
2543 int
2545 {
2549 {
2550 /* You're supposed to have one `template <...>' for every
2551 template class, but you don't need one for a full
2552 specialization. For example:
2554 template <class T> struct S{};
2555 template <> struct S<int> { void f(); };
2556 void S<int>::f () {}
2558 is correct; there shouldn't be a `template <>' for the
2559 definition of `S<int>::f'. */
2561 /* If CTYPE does not have template information of any
2562 kind, then it is not a template, nor is it nested
2563 within a template. */
2571 }
2574 }
2576 /* Do a simple sanity check on the template headers that precede the
2577 variable declaration DECL. */
2579 void
2581 {
2586 {
2589 "variable templates only available with "
2592 // Namespace-scope variable templates should have a template header.
2594 }
2596 {
2598 "too many template headers for %qD "
2604 "members of an explicitly specialized class are defined "
2606 }
2607 }
2609 /* An explicit specialization whose declarator-id or class-head-name is not
2610 qualified shall be declared in the nearest enclosing namespace of the
2611 template, or, if the namespace is inline (7.3.1), any namespace from its
2612 enclosing namespace set.
2614 If the name declared in the explicit instantiation is an unqualified name,
2615 the explicit instantiation shall appear in the namespace where its template
2616 is declared or, if that namespace is inline (7.3.1), any namespace from its
2617 enclosing namespace set. */
2619 void
2621 {
2626 {
2632 /* This was allowed in C++98, so only pedwarn. */
2634 "outside its namespace must use a nested-name-"
2636 }
2637 }
2639 /* Warn for a template specialization SPEC that is missing some of a set
2640 of function or type attributes that the template TEMPL is declared with.
2641 ATTRLIST is a list of additional attributes that SPEC should be taken
2642 to ultimately be declared with. */
2644 static void
2646 {
2653 /* Avoid warning if either declaration or its type is deprecated. */
2675 /* Avoid warning if the primary has no attributes. */
2679 /* Avoid warning if either declaration contains an attribute on
2680 the white list below. */
2683 };
2691 /* Avoid warning if the difference between the primary and
2692 the specialization is not in one of the attributes below. */
2696 };
2698 /* Put together a list of the black listed attributes that the primary
2699 template is declared with that the specialization is not, in case
2700 it's not apparent from the most recent declaration of the primary. */
2702 pretty_printer str;
2705 {
2707 {
2712 {
2722 }
2723 }
2724 }
2731 spec))
2737 }
2739 /* Check to see if the function just declared, as indicated in
2740 DECLARATOR, and in DECL, is a specialization of a function
2741 template. We may also discover that the declaration is an explicit
2742 instantiation at this point.
2744 Returns DECL, or an equivalent declaration that should be used
2745 instead if all goes well. Issues an error message if something is
2746 amiss. Returns error_mark_node if the error is not easily
2747 recoverable.
2749 FLAGS is a bitmask consisting of the following flags:
2751 2: The function has a definition.
2752 4: The function is a friend.
2754 The TEMPLATE_COUNT is the number of references to qualifying
2755 template classes that appeared in the name of the function. For
2756 example, in
2758 template <class T> struct S { void f(); };
2759 void S<int>::f();
2761 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2762 classes are not counted in the TEMPLATE_COUNT, so that in
2764 template <class T> struct S {};
2765 template <> struct S<int> { void f(); }
2766 template <> void S<int>::f();
2768 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2769 invalid; there should be no template <>.)
2771 If the function is a specialization, it is marked as such via
2772 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2773 is set up correctly, and it is added to the list of specializations
2774 for that template. */
2776 tree
2778 tree decl,
2781 tree attrlist)
2782 {
2791 tmpl_spec_kind tsk;
2794 {
2797 else
2799 }
2800 else
2804 {
2807 {
2810 }
2812 {
2814 /* This could be something like:
2816 template <class T> void f(T);
2817 class S { friend void f<>(int); } */
2819 else
2820 {
2821 /* This case handles bogus declarations like template <>
2822 template <class T> void f<int>(); */
2825 declarator);
2827 }
2828 }
2832 /* The error has already been reported in
2833 check_specialization_scope. */
2839 /* Fall through. */
2852 decl);
2855 else
2859 /* Fall through. */
2865 /* In cases like template<> constexpr bool v = true;
2866 We'll give an error in check_template_variable. */
2872 else
2878 {
2879 /* This case handles bogus declarations like template <>
2880 template <class T> void f<int>(); */
2884 declarator);
2886 {
2887 /* Partial specialization of variable template. */
2891 }
2895 else
2899 ok:;
2900 }
2903 /* This is a specialization of a member template, without
2904 specialization the containing class. Something like:
2906 template <class T> struct S {
2907 template <class U> void f (U);
2908 };
2909 template <> template <class U> void S<int>::f(U) {}
2911 That's a specialization -- but of the entire template. */
2917 }
2920 /* This doesn't apply to variable templates. */
2923 {
2927 {
2931 }
2932 }
2935 {
2940 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2942 {
2943 tree fns;
2948 else
2949 {
2950 /* If there is no class context, the explicit instantiation
2951 must be at namespace scope. */
2954 /* Find the namespace binding, using the declaration
2955 context. */
2959 /* If lookup fails, look for a friend declaration so we can
2960 give a better diagnostic. */
2966 {
2969 }
2970 }
2973 }
2979 {
2981 /* A specialization in class scope. This is invalid,
2982 but the error will already have been flagged by
2983 check_specialization_scope. */
2985 else
2986 {
2987 /* It's not valid to write an explicit instantiation in
2988 class scope, e.g.:
2990 class C { template void f(); }
2992 This case is caught by the parser. However, on
2993 something like:
2995 template class C { void f(); };
2997 (which is invalid) we can get here. The error will be
2998 issued later. */
2999 ;
3000 }
3003 }
3006 {
3007 // We'll match variable templates in start_decl.
3011 /* Find the list of functions in ctype that have the same
3012 name as the declared function. */
3016 {
3020 {
3021 /* From [temp.expl.spec]:
3023 If such an explicit specialization for the member
3024 of a class template names an implicitly-declared
3025 special member function (clause _special_), the
3026 program is ill-formed.
3028 Similar language is found in [temp.explicit]. */
3031 }
3034 }
3036 /* For a type-conversion operator, We might be looking for
3037 `operator int' which will be a specialization of
3038 `operator T'. Grab all the conversion operators, and
3039 then select from them. */
3044 {
3047 }
3048 else
3050 }
3052 /* Figure out what exactly is being specialized at this point.
3053 Note that for an explicit instantiation, even one for a
3054 member function, we cannot tell a priori whether the
3055 instantiation is for a member template, or just a member
3056 function of a template class. Even if a member template is
3057 being instantiated, the member template arguments may be
3058 elided if they can be deduced from the rest of the
3059 declaration. */
3062 member_specialization,
3063 template_count,
3064 tsk);
3067 /* We couldn't figure out what this declaration was
3068 specializing. */
3070 else
3071 {
3074 {
3076 "friend declaration %qD is not visible to "
3080 }
3088 {
3089 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3090 is done by do_decl_instantiation later. */
3096 {
3097 /* If TMPL is not the most general template (for
3098 example, if TMPL is a friend template that is
3099 injected into namespace scope), then there will
3100 be too many levels of TARGS. Remove some of them
3101 here. */
3103 tree new_targs;
3110 }
3113 }
3115 /* If we thought that the DECL was a member function, but it
3116 turns out to be specializing a static member function,
3117 make DECL a static member function as well. */
3123 /* If this is a specialization of a member template of a
3124 template class, we want to return the TEMPLATE_DECL, not
3125 the specialization of it. */
3127 {
3132 {
3133 tree parm;
3137 /* We want to use the argument list specified in the
3138 definition, not in the original declaration. */
3143 }
3146 }
3148 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3154 /* Inherit default function arguments from the template
3155 DECL is specializing. */
3159 /* This specialization has the same protection as the
3160 template it specializes. */
3164 /* 7.1.1-1 [dcl.stc]
3166 A storage-class-specifier shall not be specified in an
3167 explicit specialization...
3169 The parser rejects these, so unless action is taken here,
3170 explicit function specializations will always appear with
3171 global linkage.
3173 The action recommended by the C++ CWG in response to C++
3174 defect report 605 is to make the storage class and linkage
3175 of the explicit specialization match the templated function:
3177 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3178 */
3180 {
3184 /* A concept cannot be specialized. */
3186 {
3188 gen_tmpl);
3190 }
3192 /* This specialization has the same linkage and visibility as
3193 the function template it specializes. */
3196 {
3199 }
3202 {
3205 }
3206 }
3208 /* If DECL is a friend declaration, declared using an
3209 unqualified name, the namespace associated with DECL may
3210 have been set incorrectly. For example, in:
3212 template <typename T> void f(T);
3213 namespace N {
3214 struct S { friend void f<int>(int); }
3215 }
3217 we will have set the DECL_CONTEXT for the friend
3218 declaration to N, rather than to the global namespace. */
3223 /* This is not really a declaration of a specialization.
3224 It's just the name of an instantiation. But, it's not
3225 a request for an instantiation, either. */
3228 /* A specialization is not necessarily COMDAT. */
3234 /* If this is a full specialization, register it so that we can find
3235 it again. Partial specializations will be registered in
3236 process_partial_specialization. */
3238 {
3243 }
3246 /* A 'structor should already have clones. */
3252 }
3253 }
3256 }
3258 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3259 parameters. These are represented in the same format used for
3260 DECL_TEMPLATE_PARMS. */
3262 int
3264 {
3265 const_tree p1;
3266 const_tree p2;
3274 {
3286 {
3290 /* If either of the template parameters are invalid, assume
3291 they match for the sake of error recovery. */
3304 }
3305 }
3308 /* One set of parameters has more parameters lists than the
3309 other. */
3313 }
3315 /* Determine whether PARM is a parameter pack. */
3317 bool
3319 {
3320 /* Determine if we have a non-type template parameter pack. */
3327 /* If this is a list of template parameters, we could get a
3328 TYPE_DECL or a TEMPLATE_DECL. */
3332 /* Otherwise it must be a type template parameter. */
3336 }
3338 /* Determine if T is a function parameter pack. */
3340 bool
3342 {
3346 }
3348 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3349 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3351 tree
3353 {
3360 }
3362 /* Return true iff the function parameter PARAM_DECL was expanded
3363 from the function parameter pack PACK. */
3365 bool
3367 {
3372 /* The parameter pack and its pack arguments have the same
3373 DECL_PARM_INDEX. */
3375 }
3377 /* Determine whether ARGS describes a variadic template args list,
3378 i.e., one that is terminated by a template argument pack. */
3380 static bool
3382 {
3384 tree last_parm;
3398 }
3400 /* Generate a new name for the parameter pack name NAME (an
3401 IDENTIFIER_NODE) that incorporates its */
3403 static tree
3405 {
3406 /* Munge the name to include the parameter index. */
3407 #define NUMBUF_LEN 128
3421 }
3423 /* Return true if T is a primary function, class or alias template
3424 specialization, not including the template pattern. */
3426 bool
3428 {
3444 }
3446 /* Return true if PARM is a template template parameter. */
3448 bool
3450 {
3452 }
3454 /* Return true iff PARM is a DECL representing a type template
3455 parameter. */
3457 bool
3459 {
3464 }
3466 /* Return the template parameters of T if T is a
3467 primary template instantiation, NULL otherwise. */
3469 tree
3471 {
3476 parms = INNERMOST_TEMPLATE_PARMS
3480 }
3482 /* Return the template parameters of the LEVELth level from the full list
3483 of template parameters PARMS. */
3485 tree
3487 {
3488 tree p;
3499 }
3501 /* Returns the template arguments of T if T is a template instantiation,
3502 NULL otherwise. */
3504 tree
3506 {
3514 }
3516 /* Return the argument pack elements of T if T is a template argument pack,
3517 NULL otherwise. */
3519 tree
3521 {
3527 }
3529 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3530 ARGUMENT_PACK_SELECT represents. */
3532 static tree
3534 {
3538 /* If the selected argument is an expansion E, that most likely means we were
3539 called from gen_elem_of_pack_expansion_instantiation during the
3540 substituting of an argument pack (of which the Ith element is a pack
3541 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3542 In this case, the Ith element resulting from this substituting is going to
3543 be a pack expansion, which pattern is the pattern of E. Let's return the
3544 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3545 resulting pack expansion from it. */
3547 {
3548 /* Make sure we aren't throwing away arg info. */
3551 }
3554 }
3557 /* True iff FN is a function representing a built-in variadic parameter
3558 pack. */
3560 bool
3562 {
3572 }
3574 /* True iff CALL is a call to a function representing a built-in variadic
3575 parameter pack. */
3577 static bool
3579 {
3583 }
3585 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3587 static tree
3589 tree in_decl)
3590 {
3596 {
3598 {
3601 }
3606 }
3607 else
3608 {
3612 /* Calculate the largest value of len that won't make the size of the vec
3613 overflow an int. The compiler will exceed resource limits long before
3614 this, but it seems a decent place to diagnose. */
3618 {
3623 }
3631 }
3632 }
3634 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3635 CALL. */
3637 static tree
3639 tree in_decl)
3640 {
3650 }
3652 /* Structure used to track the progress of find_parameter_packs_r. */
3653 struct find_parameter_pack_data
3654 {
3655 /* TREE_LIST that will contain all of the parameter packs found by
3656 the traversal. */
3659 /* Set of AST nodes that have been visited by the traversal. */
3662 /* True iff we're making a type pack expansion. */
3664 };
3666 /* Identifies all of the argument packs that occur in a template
3667 argument and appends them to the TREE_LIST inside DATA, which is a
3668 find_parameter_pack_data structure. This is a subroutine of
3669 make_pack_expansion and uses_parameter_packs. */
3670 static tree
3672 {
3678 /* Handle type aliases/typedefs. */
3680 {
3687 }
3689 /* Identify whether this is a parameter pack or not. */
3691 {
3699 /* FALLTHRU */
3701 /* If the placeholder appears in the decl-specifier-seq of a function
3702 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3703 is a pack expansion, the invented template parameter is a template
3704 parameter pack. */
3714 {
3715 /* We don't want to walk into the type of a PARM_DECL,
3716 because we don't want to see the type parameter pack. */
3719 }
3724 {
3725 /* We don't want to walk into the type of a variadic capture proxy,
3726 because we don't want to see the type parameter pack. */
3729 }
3731 {
3733 find_parameter_packs_r,
3736 }
3748 /* Not a parameter pack. */
3750 }
3753 {
3754 /* Add this parameter pack to the list. */
3756 }
3762 /* This switch statement will return immediately if we don't find a
3763 parameter pack. */
3765 {
3770 /* Check the template itself. */
3773 /* Check the template arguments. */
3787 /* Ignore the declaration of a capture proxy for a parameter pack. */
3795 /* Fall through. */
3840 {
3841 /* Look at explicit captures. */
3846 /* Since we defer implicit capture, look in the body as well. */
3852 }
3855 {
3856 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3857 type_pack_expansion_p to false so that any placeholders
3858 within the expression don't get marked as parameter packs. */
3866 }
3870 }
3873 }
3875 /* Determines if the expression or type T uses any parameter packs. */
3876 bool
3878 {
3887 }
3889 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3890 representation a base-class initializer into a parameter pack
3891 expansion. If all goes well, the resulting node will be an
3892 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3893 respectively. */
3894 tree
3896 {
3897 tree result;
3906 {
3907 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3908 class initializer. In this case, the TREE_PURPOSE will be a
3909 _TYPE node (representing the base class expansion we're
3910 initializing) and the TREE_VALUE will be a TREE_LIST
3911 containing the initialization arguments.
3913 The resulting expansion looks somewhat different from most
3914 expansions. Rather than returning just one _EXPANSION, we
3915 return a TREE_LIST whose TREE_PURPOSE is a
3916 TYPE_PACK_EXPANSION containing the bases that will be
3917 initialized. The TREE_VALUE will be identical to the
3918 original TREE_VALUE, which is a list of arguments that will
3919 be passed to each base. We do not introduce any new pack
3920 expansion nodes into the TREE_VALUE (although it is possible
3921 that some already exist), because the TREE_PURPOSE and
3922 TREE_VALUE all need to be expanded together with the same
3923 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3924 resulting TREE_PURPOSE will mention the parameter packs in
3925 both the bases and the arguments to the bases. */
3926 tree purpose;
3927 tree value;
3930 /* Determine which parameter packs will be used by the base
3931 class expansion. */
3940 {
3943 arg);
3946 }
3949 {
3950 /* Collect the sets of parameter packs used in each of the
3951 initialization arguments. */
3953 {
3954 /* Determine which parameter packs will be expanded in this
3955 argument. */
3958 }
3959 }
3963 /* Create the pack expansion type for the base type. */
3969 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3970 they will rarely be compared to anything. */
3974 }
3979 /* Build the PACK_EXPANSION_* node. */
3980 result = for_types
3985 {
3986 /* Propagate type and const-expression information. */
3989 /* Mark this read now, since the expansion might be length 0. */
3991 }
3992 else
3993 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3994 they will rarely be compared to anything. */
3997 /* Determine which parameter packs will be expanded. */
4004 /* Make sure we found some parameter packs. */
4006 {
4008 {
4011 else
4013 }
4015 }
4021 }
4023 /* Checks T for any "bare" parameter packs, which have not yet been
4024 expanded, and issues an error if any are found. This operation can
4025 only be done on full expressions or types (e.g., an expression
4026 statement, "if" condition, etc.), because we could have expressions like:
4028 foo(f(g(h(args)))...)
4030 where "args" is a parameter pack. check_for_bare_parameter_packs
4031 should not be called for the subexpressions args, h(args),
4032 g(h(args)), or f(g(h(args))), because we would produce erroneous
4033 error messages.
4035 Returns TRUE and emits an error if there were bare parameter packs,
4036 returns FALSE otherwise. */
4037 bool
4039 {
4046 /* A lambda might use a parameter pack from the containing context. */
4061 {
4065 {
4076 else
4081 else
4085 }
4088 }
4091 }
4093 /* Expand any parameter packs that occur in the template arguments in
4094 ARGS. */
4095 tree
4097 {
4106 /* First, determine if we need to expand anything, and the number of
4107 slots we'll need. */
4109 {
4114 {
4118 else
4120 }
4121 else
4122 {
4124 num_result_args++;
4125 }
4126 }
4128 /* If no expansion is necessary, we're done. */
4132 /* Expand arguments. */
4135 non_default_args_count =
4138 {
4141 {
4148 }
4149 else
4150 {
4153 }
4154 }
4158 }
4160 /* Checks if DECL shadows a template parameter.
4162 [temp.local]: A template-parameter shall not be redeclared within its
4163 scope (including nested scopes).
4165 Emits an error and returns TRUE if the DECL shadows a parameter,
4166 returns FALSE otherwise. */
4168 bool
4170 {
4171 tree olddecl;
4173 /* If we're not in a template, we can't possibly shadow a template
4174 parameter. */
4178 /* Figure out what we're shadowing. */
4182 /* If there's no previous binding for this name, we're not shadowing
4183 anything, let alone a template parameter. */
4187 /* If we're not shadowing a template parameter, we're done. Note
4188 that OLDDECL might be an OVERLOAD (or perhaps even an
4189 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4190 node. */
4194 /* We check for decl != olddecl to avoid bogus errors for using a
4195 name inside a class. We check TPFI to avoid duplicate errors for
4196 inline member templates. */
4202 /* Don't complain about the injected class name, as we've already
4203 complained about the class itself. */
4210 else
4215 }
4217 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4218 ORIG_LEVEL, DECL, and TYPE. */
4220 static tree
4224 tree decl,
4225 tree type)
4226 {
4237 }
4239 /* Find the canonical type parameter for the given template type
4240 parameter. Returns the canonical type parameter, which may be TYPE
4241 if no such parameter existed. */
4243 static tree
4245 {
4246 tree list;
4260 else
4261 {
4265 }
4266 }
4268 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4269 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4270 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4271 new one is created. */
4273 static tree
4275 tsubst_flags_t complain)
4276 {
4281 {
4300 /* Template template parameters need this. */
4302 {
4309 }
4310 }
4313 }
4315 /* Process information from new template parameter PARM and append it
4316 to the LIST being built. This new parameter is a non-type
4317 parameter iff IS_NON_TYPE is true. This new parameter is a
4318 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4319 is in PARM_LOC. */
4321 tree
4324 {
4333 {
4337 {
4341 else
4343 }
4346 }
4349 {
4355 {
4356 /* [temp.param]
4358 The top-level cv-qualifiers on the template-parameter are
4359 ignored when determining its type. */
4364 && !is_parameter_pack
4365 /* If we're in a nested template parameter list, the template
4366 template parameter could be a parameter pack. */
4368 {
4369 /* This template parameter is not a parameter pack, but it
4370 should be. Complain about "bare" parameter packs. */
4373 /* Recover by calling this a parameter pack. */
4375 }
4376 }
4378 /* A template parameter is not modifiable. */
4387 processing_template_decl,
4392 }
4393 else
4394 {
4395 tree t;
4399 {
4401 /* This is for distinguishing between real templates and template
4402 template parameters */
4406 }
4407 else
4408 {
4410 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4413 }
4420 processing_template_decl,
4424 }
4428 /* Build requirements for the type/template parameter.
4429 This must be done after SET_DECL_TEMPLATE_PARM_P or
4430 process_template_parm could fail. */
4438 /* Build the parameter node linking the parameter declaration,
4439 its default argument (if any), and its constraints (if any). */
4444 }
4446 /* The end of a template parameter list has been reached. Process the
4447 tree list into a parameter vector, converting each parameter into a more
4448 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4449 as PARM_DECLs. */
4451 tree
4453 {
4458 /* Pop the dummy parameter level and add the real one. */
4461 current_template_parms
4466 {
4470 }
4475 }
4477 // Explicitly indicate the end of the template parameter list. We assume
4478 // that the current template parameters have been constructed and/or
4479 // managed explicitly, as when creating new template template parameters
4480 // from a shorthand constraint.
4481 void
4483 {
4485 }
4487 /* end_template_decl is called after a template declaration is seen. */
4489 void
4491 {
4497 /* This matches the pushlevel in begin_template_parm_list. */
4502 }
4504 /* Takes a TREE_LIST representing a template parameter and convert it
4505 into an argument suitable to be passed to the type substitution
4506 functions. Note that If the TREE_LIST contains an error_mark
4507 node, the returned argument is error_mark_node. */
4509 tree
4511 {
4524 {
4528 {
4529 /* Turn this argument into a TYPE_ARGUMENT_PACK
4530 with a single element, which expands T. */
4539 }
4540 }
4541 else
4542 {
4546 {
4547 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4548 with a single element, which expands T. */
4558 }
4559 else
4561 }
4563 }
4565 /* Given a single level of template parameters (a TREE_VEC), return it
4566 as a set of template arguments. */
4568 static tree
4570 {
4580 }
4582 /* Given a set of template parameters, return them as a set of template
4583 arguments. The template parameters are represented as a TREE_VEC, in
4584 the form documented in cp-tree.h for template arguments. */
4586 static tree
4588 {
4589 tree header;
4594 /* If there is only one level of template parameters, we do not
4595 create a TREE_VEC of TREE_VECs. Instead, we return a single
4596 TREE_VEC containing the arguments. */
4601 {
4606 else
4608 }
4611 }
4613 /* Within the declaration of a template, return the currently active
4614 template parameters as an argument TREE_VEC. */
4616 static tree
4618 {
4620 }
4622 /* Update the declared TYPE by doing any lookups which were thought to be
4623 dependent, but are not now that we know the SCOPE of the declarator. */
4625 tree
4627 {
4638 /* Don't bother building up the args in this case. */
4640 {
4641 /* tsubst in the args corresponding to the template parameters,
4642 including auto if present. Most things will be unchanged, but
4643 make_typename_type and tsubst_qualified_id will resolve
4644 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4647 tree pushed;
4649 {
4653 }
4658 }
4664 {
4667 else
4669 }
4671 }
4673 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4674 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4675 the new template is a member template. */
4677 static tree
4679 {
4688 }
4690 struct template_parm_data
4691 {
4692 /* The level of the template parameters we are currently
4693 processing. */
4696 /* The index of the specialization argument we are currently
4697 processing. */
4700 /* An array whose size is the number of template parameters. The
4701 elements are nonzero if the parameter has been used in any one
4702 of the arguments processed so far. */
4705 /* An array whose size is the number of template arguments. The
4706 elements are nonzero if the argument makes use of template
4707 parameters of this level. */
4709 };
4711 /* Subroutine of push_template_decl used to see if each template
4712 parameter in a partial specialization is used in the explicit
4713 argument list. If T is of the LEVEL given in DATA (which is
4714 treated as a template_parm_data*), then DATA->PARMS is marked
4715 appropriately. */
4717 static int
4719 {
4727 {
4730 }
4732 /* In C++17 the type of a non-type argument is a deduced context. */
4737 data,
4738 NULL,
4741 /* Return zero so that for_each_template_parm will continue the
4742 traversal of the tree; we want to mark *every* template parm. */
4744 }
4746 /* Process the partial specialization DECL. */
4748 static tree
4750 {
4757 tree inner_parms;
4758 tree inst;
4768 /* A concept cannot be specialized. */
4770 {
4773 }
4778 /* We check that each of the template parameters given in the
4779 partial specialization is used in the argument list to the
4780 specialization. For example:
4782 template <class T> struct S;
4783 template <class T> struct S<T*>;
4785 The second declaration is OK because `T*' uses the template
4786 parameter T, whereas
4788 template <class T> struct S<int>;
4790 is no good. Even trickier is:
4792 template <class T>
4793 struct S1
4794 {
4795 template <class U>
4796 struct S2;
4797 template <class U>
4798 struct S2<T>;
4799 };
4801 The S2<T> declaration is actually invalid; it is a
4802 full-specialization. Of course,
4804 template <class U>
4805 struct S2<T (*)(U)>;
4807 or some such would have been OK. */
4815 {
4820 NULL,
4822 }
4825 {
4826 /* One of the template parms was not used in a deduced context in the
4827 specialization. */
4829 {
4833 }
4837 }
4842 /* [temp.class.spec]
4844 The argument list of the specialization shall not be identical to
4845 the implicit argument list of the primary template. */
4846 tree main_args
4849 && (!flag_concepts
4852 {
4855 "any template arguments; to define the primary template, "
4857 else
4859 "template arguments and is not more constrained than "
4860 "the primary template; to define the primary template, "
4863 }
4865 /* A partial specialization that replaces multiple parameters of the
4866 primary template with a pack expansion is less specialized for those
4867 parameters. */
4869 {
4871 "primary template because it replaces multiple parameters "
4874 /* Avoid crash in process_partial_specialization. */
4876 }
4878 /* If we aren't in a dependent class, we can actually try deduction. */
4880 /* FIXME we should be able to handle a partial specialization of a
4881 partial instantiation, but currently we can't (c++/41727). */
4884 {
4888 maintmpl);
4889 }
4891 /* [temp.class.spec]
4893 A partially specialized non-type argument expression shall not
4894 involve template parameters of the partial specialization except
4895 when the argument expression is a simple identifier.
4897 The type of a template parameter corresponding to a specialized
4898 non-type argument shall not be dependent on a parameter of the
4899 specialization.
4901 Also, we verify that pack expansions only occur at the
4902 end of the argument list. */
4906 {
4913 {
4914 /* Extract the arguments from the argument pack. We'll be
4915 iterating over these in the following loop. */
4918 }
4921 {
4923 /* Get the Jth argument in the parameter pack. */
4927 {
4928 /* Pack expansions must come at the end of the
4929 argument list. */
4932 {
4936 else
4939 }
4940 }
4943 /* We only care about the pattern. */
4949 /* This next two lines are the `argument expression is not just a
4950 simple identifier' condition and also the `specialized
4951 non-type argument' bit. */
4955 {
4959 arg);
4960 else
4961 {
4962 /* Look at the corresponding template parameter,
4963 marking which template parameters its type depends
4964 upon. */
4968 {
4969 /* We haven't yet initialized TPD2. Do so now. */
4971 /* The number of parameters here is the number in the
4972 main template, which, as checked in the assertion
4973 above, is NARGS. */
4977 }
4979 /* Mark the template parameters. But this time, we're
4980 looking for the template parameters of the main
4981 template, not in the specialization. */
4988 NULL,
4992 {
4993 /* The type depended on some template parameters.
4994 If they are fully specialized in the
4995 specialization, that's OK. */
5004 "type %qT of template argument %qE depends "
5006 "type %qT of template argument %qE depends "
5008 type,
5009 arg);
5010 }
5011 }
5012 }
5013 }
5014 }
5016 /* We should only get here once. */
5020 // Build the template decl.
5029 /* Give template template parms a DECL_CONTEXT of the template
5030 for which they are a parameter. */
5032 {
5036 }
5039 /* We didn't register this in check_explicit_specialization so we could
5040 wait until the constraints were set. */
5042 else
5052 {
5058 {
5066 "declaration of %qD ambiguates earlier template "
5070 "partial specialization of %qD after instantiation "
5072 }
5073 }
5076 }
5078 /* PARM is a template parameter of some form; return the corresponding
5079 TEMPLATE_PARM_INDEX. */
5081 static tree
5083 {
5096 }
5098 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5099 parameter packs used by the template parameter PARM. */
5101 static void
5103 {
5104 /* A type parm can't refer to another parm. */
5108 {
5112 }
5119 }
5121 /* PARM is a template parameter pack. Return any parameter packs used in
5122 its type or the type of any of its template parameters. If there are
5123 any such packs, it will be instantiated into a fixed template parameter
5124 list by partial instantiation rather than be fully deduced. */
5126 tree
5128 {
5129 /* This can only be true in a member template. */
5132 /* This can only be true for a parameter pack. */
5135 /* A type parm can't refer to another parm. */
5149 }
5151 /* Check that a template declaration's use of default arguments and
5152 parameter packs is not invalid. Here, PARMS are the template
5153 parameters. IS_PRIMARY is true if DECL is the thing declared by
5154 a primary template. IS_PARTIAL is true if DECL is a partial
5155 specialization.
5157 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5158 function template declaration or a friend class template
5159 declaration. In the function case, 1 indicates a declaration, 2
5160 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5161 emitted for extraneous default arguments.
5163 Returns TRUE if there were no errors found, FALSE otherwise. */
5165 bool
5168 {
5171 tree parm_level;
5174 /* [temp.param]
5176 A default template-argument shall not be specified in a
5177 function template declaration or a function template definition, nor
5178 in the template-parameter-list of the definition of a member of a
5179 class template. */
5183 /* You can't have a function template declaration in a local
5184 scope, nor you can you define a member of a class template in a
5185 local scope. */
5193 /* A lambda doesn't have an explicit declaration; don't complain
5194 about the parms of the enclosing class. */
5201 /* If this is either a friend defined in the scope of the class
5202 or a member function. */
5208 /* And, if it was a member function, it really was defined in
5209 the scope of the class. */
5212 /* We already checked these parameters when the template was
5213 declared, so there's no need to do it again now. This function
5214 was defined in class scope, but we're processing its body now
5215 that the class is complete. */
5218 /* Core issue 226 (C++0x only): the following only applies to class
5219 templates. */
5222 {
5223 /* [temp.param]
5225 If a template-parameter has a default template-argument, all
5226 subsequent template-parameters shall have a default
5227 template-argument supplied. */
5229 {
5236 {
5246 {
5248 /* For better subsequent error-recovery, we indicate that
5249 there should have been a default argument. */
5252 }
5254 && !is_friend_decl
5255 /* Don't complain about an enclosing partial
5256 specialization. */
5261 /* A fixed parameter pack will be partially
5262 instantiated into a fixed length list. */
5264 {
5265 /* A primary class template can only have one
5266 parameter pack, at the end of the template
5267 parameter list. */
5275 }
5276 }
5277 }
5278 }
5281 || is_partial
5282 || !is_primary
5284 /* For an ordinary class template, default template arguments are
5285 allowed at the innermost level, e.g.:
5286 template <class T = int>
5287 struct S {};
5288 but, in a partial specialization, they're not allowed even
5289 there, as we have in [temp.class.spec]:
5291 The template parameter list of a specialization shall not
5292 contain default template argument values.
5294 So, for a partial specialization, or for a function template
5295 (in C++98/C++03), we look at all of them. */
5296 ;
5297 else
5298 /* But, for a primary class template that is not a partial
5299 specialization we look at all template parameters except the
5300 innermost ones. */
5303 /* Figure out what error message to issue. */
5318 else
5319 /* Per [temp.param]/9, "A default template-argument shall not be
5320 specified in the template-parameter-lists of the definition of
5321 a member of a class template that appears outside of the member's
5322 class.", thus if we aren't handling a member of a class template
5323 there is no need to examine the parameters. */
5327 /* If we're inside a class definition, there's no need to
5328 examine the parameters to the class itself. On the one
5329 hand, they will be checked when the class is defined, and,
5330 on the other, default arguments are valid in things like:
5331 template <class T = double>
5332 struct S { template <class U> void f(U); };
5333 Here the default argument for `S' has no bearing on the
5334 declaration of `f'. */
5336 else
5337 /* Check everything. */
5343 {
5350 {
5355 {
5357 {
5364 }
5366 /* Clear out the default argument so that we are not
5367 confused later. */
5369 }
5370 }
5372 /* At this point, if we're still interested in issuing messages,
5373 they must apply to classes surrounding the object declared. */
5377 }
5380 }
5382 /* Worker for push_template_decl_real, called via
5383 for_each_template_parm. DATA is really an int, indicating the
5384 level of the parameters we are interested in. If T is a template
5385 parameter of that level, return nonzero. */
5387 static int
5389 {
5395 else
5398 }
5400 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5401 DATA is really an int, indicating the innermost outer level of parameters.
5402 If T is a template parameter of that level or further out, return
5403 nonzero. */
5405 static int
5407 {
5413 else
5416 }
5418 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5419 parameters given by current_template_args, or reuses a
5420 previously existing one, if appropriate. Returns the DECL, or an
5421 equivalent one, if it is replaced via a call to duplicate_decls.
5423 If IS_FRIEND is true, DECL is a friend declaration. */
5425 tree
5427 {
5428 tree tmpl;
5429 tree args;
5430 tree info;
5431 tree ctx;
5435 /* True if the template is a member template, in the sense of
5436 [temp.mem]. */
5442 /* See if this is a partial specialization. */
5455 /* For a friend, we want the context of the friend, not
5456 the type of which it is a friend. */
5460 /* In the case of a virtual function, we want the class in which
5461 it is defined. */
5463 else
5464 /* Otherwise, if we're currently defining some class, the DECL
5465 is assumed to be a member of the class. */
5474 /* See if this is a primary template. */
5477 /* A friend template that specifies a class context, i.e.
5478 template <typename T> friend void A<T>::f();
5479 is not primary. */
5484 else
5488 {
5495 {
5498 }
5500 {
5502 {
5505 }
5507 {
5508 /* [temp.mem]
5510 A destructor shall not be a member template. */
5513 }
5520 {
5521 /* [basic.stc.dynamic.allocation]
5523 An allocation function can be a function
5524 template. ... Template allocation functions shall
5525 have two or more parameters. */
5528 }
5529 }
5532 {
5533 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5536 {
5542 }
5543 }
5546 /* alias-declaration */
5550 else
5551 {
5554 }
5555 }
5557 /* Check to see that the rules regarding the use of default
5558 arguments are not being violated. We check args for a friend
5559 functions when we know whether it's a definition, introducing
5560 declaration or re-declaration. */
5565 /* Ensure that there are no parameter packs in the type of this
5566 declaration that have not been expanded. */
5568 {
5569 /* Check each of the arguments individually to see if there are
5570 any bare parameter packs. */
5576 {
5579 {
5580 /* This is a PARM_DECL that contains unexpanded parameter
5581 packs. We have already complained about this in the
5582 check_for_bare_parameter_packs call, so just replace
5583 these types with ERROR_MARK_NODE. */
5586 }
5590 }
5592 /* Check for bare parameter packs in the return type and the
5593 exception specifiers. */
5595 /* Errors were already issued, set return type to int
5596 as the frontend doesn't expect error_mark_node as
5597 the return type. */
5601 }
5606 {
5609 }
5622 {
5627 /* If DECL is a TYPE_DECL for a class-template, then there won't
5628 be DECL_LANG_SPECIFIC. The information equivalent to
5629 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5633 {
5634 /* Since a template declaration already existed for this
5635 class-type, we must be redeclaring it here. Make sure
5636 that the redeclaration is valid. */
5638 current_template_parms,
5640 /* We don't need to create a new TEMPLATE_DECL; just use the
5641 one we already had. */
5643 }
5644 else
5645 {
5647 member_template_p);
5652 {
5653 /* A specialization of a member template of a template
5654 class. */
5658 }
5659 }
5660 }
5661 else
5662 {
5668 {
5671 }
5679 {
5680 tree new_tmpl;
5682 /* The declaration is a specialization of a member
5683 template, declared outside the class. Therefore, the
5684 innermost template arguments will be NULL, so we
5685 replace them with the arguments determined by the
5686 earlier call to check_explicit_specialization. */
5689 new_tmpl
5691 member_template_p);
5701 args,
5704 }
5706 /* Make sure the template headers we got make sense. */
5711 {
5716 }
5717 else
5719 {
5724 {
5728 else
5732 /* Avoid crash in import_export_decl. */
5735 }
5740 /* Can happen in erroneous input. */
5742 else
5744 }
5746 /* Check that the parms are used in the appropriate qualifying scopes
5747 in the declarator. */
5751 {
5757 /* Avoid crash in import_export_decl. */
5760 }
5761 }
5766 /* Push template declarations for global functions and types. Note
5767 that we do not try to push a global template friend declared in a
5768 template class; such a thing may well depend on the template
5769 parameters of the class. */
5772 {
5777 /* Hide template friend classes that haven't been declared yet. */
5779 {
5782 }
5783 }
5786 {
5791 /* Give template template parms a DECL_CONTEXT of the template
5792 for which they are a parameter. */
5795 {
5799 }
5805 }
5807 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5808 back to its most general template. If TMPL is a specialization,
5809 ARGS may only have the innermost set of arguments. Add the missing
5810 argument levels if necessary. */
5818 else
5819 {
5824 }
5827 && !is_friend
5830 /* Set DECL_COMDAT on template instantiations; if we force
5831 them to be emitted by explicit instantiation or -frepo,
5832 mark_needed will tell cgraph to do the right thing. */
5836 }
5838 tree
5840 {
5842 }
5844 /* FN is an inheriting constructor that inherits from the constructor
5845 template INHERITED; turn FN into a constructor template with a matching
5846 template header. */
5848 tree
5850 {
5851 tree inner_parms
5854 tree parms
5865 }
5867 /* Called when a class template TYPE is redeclared with the indicated
5868 template PARMS, e.g.:
5870 template <class T> struct S;
5871 template <class T> struct S {}; */
5873 bool
5875 {
5876 tree tmpl;
5877 tree tmpl_parms;
5881 {
5884 }
5888 /* The type is nested in some template class. Nothing to worry
5889 about here; there are no new template parameters for the nested
5890 type. */
5894 {
5896 tmpl);
5898 }
5904 {
5914 }
5917 {
5918 tree tmpl_parm;
5919 tree parm;
5920 tree tmpl_default;
5921 tree parm_default;
5935 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5936 TEMPLATE_DECL. */
5946 {
5950 }
5953 {
5954 /* We have in [temp.param]:
5956 A template-parameter may not be given default arguments
5957 by two different declarations in the same scope. */
5962 }
5965 /* Update the previous template parameters (which are the ones
5966 that will really count) with the new default value. */
5969 /* Update the new parameters, too; they'll be used as the
5970 parameters for any members. */
5973 /* Give each template template parm in this redeclaration a
5974 DECL_CONTEXT of the template for which they are a parameter. */
5976 {
5979 }
5983 }
5985 // Cannot redeclare a class template with a different set of constraints.
5987 {
5992 }
5995 }
5997 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5998 to be used when the caller has already checked
5999 (processing_template_decl
6000 && !instantiation_dependent_expression_p (expr)
6001 && potential_constant_expression (expr))
6002 and cleared processing_template_decl. */
6004 tree
6006 {
6009 complain,
6013 }
6015 /* Simplify EXPR if it is a non-dependent expression. Returns the
6016 (possibly simplified) expression. */
6018 tree
6020 {
6024 /* If we're in a template, but EXPR isn't value dependent, simplify
6025 it. We're supposed to treat:
6027 template <typename T> void f(T[1 + 1]);
6028 template <typename T> void f(T[2]);
6030 as two declarations of the same function, for example. */
6033 {
6034 processing_template_decl_sentinel s;
6036 }
6038 }
6040 tree
6042 {
6044 }
6046 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6047 an uninstantiated expression. */
6049 tree
6051 {
6055 {
6058 else
6059 {
6060 processing_template_decl_sentinel s;
6062 }
6063 }
6065 }
6067 /* True iff T is a specialization of a variable template. */
6069 bool
6071 {
6076 }
6078 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6079 template declaration, or a TYPE_DECL for an alias declaration. */
6081 bool
6083 {
6091 }
6093 /* Return TRUE iff T is a specialization of an alias template. */
6095 bool
6097 {
6098 /* It's an alias template specialization if it's an alias and its
6099 TYPE_NAME is a specialization of a primary template. */
6105 }
6107 /* An alias template is complex from a SFINAE perspective if a template-id
6108 using that alias can be ill-formed when the expansion is not, as with
6109 the void_t template. We determine this by checking whether the
6110 expansion for the alias template uses all its template parameters. */
6112 struct uses_all_template_parms_data
6113 {
6116 };
6118 static int
6120 {
6128 }
6130 static bool
6132 {
6147 }
6149 /* Return TRUE iff T is a specialization of a complex alias template with
6150 dependent template-arguments. */
6152 bool
6154 {
6167 }
6169 /* Return the number of innermost template parameters in TMPL. */
6171 static int
6173 {
6176 }
6178 /* Return either TMPL or another template that it is equivalent to under DR
6179 1286: An alias that just changes the name of a template is equivalent to
6180 the other template. */
6182 static tree
6184 {
6187 {
6188 /* Determine if the alias is equivalent to an underlying template. */
6200 tree alias_args = INNERMOST_TEMPLATE_ARGS
6205 /* Alias is equivalent. Strip it and repeat. */
6207 }
6210 }
6212 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6213 must be a reference-to-function or a pointer-to-function type, as specified
6214 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6215 and check that the resulting function has external linkage. */
6217 static tree
6219 tsubst_flags_t complain)
6220 {
6223 linkage_kind linkage;
6238 /* [temp.arg.nontype]/1
6240 A template-argument for a non-type, non-template template-parameter
6241 shall be one of:
6242 [...]
6243 -- the address of an object or function with external [C++11: or
6244 internal] linkage. */
6247 {
6249 {
6255 else
6258 }
6260 }
6264 {
6266 {
6271 else
6275 }
6277 }
6279 accept:
6281 {
6284 else
6286 }
6291 }
6293 /* Subroutine of convert_nontype_argument.
6294 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6295 Emit an error otherwise. */
6297 static bool
6299 tsubst_flags_t complain)
6300 {
6317 {
6322 else
6324 }
6326 }
6328 /* Returns TRUE iff the address of OP is value-dependent.
6330 14.6.2.4 [temp.dep.temp]:
6331 A non-integral non-type template-argument is dependent if its type is
6332 dependent or it has either of the following forms
6333 qualified-id
6334 & qualified-id
6335 and contains a nested-name-specifier which specifies a class-name that
6336 names a dependent type.
6338 We generalize this to just say that the address of a member of a
6339 dependent class is value-dependent; the above doesn't cover the
6340 address of a static data member named with an unqualified-id. */
6342 static bool
6344 {
6345 /* We could use get_inner_reference here, but there's no need;
6346 this is only relevant for template non-type arguments, which
6347 can only be expressed as &id-expression. */
6349 {
6353 }
6356 }
6358 /* The next set of functions are used for providing helpful explanatory
6359 diagnostics for failed overload resolution. Their messages should be
6360 indented by two spaces for consistency with the messages in
6361 call.c */
6363 static int
6365 {
6367 }
6369 /* Other failure functions should call this one, to provide a single function
6370 for setting a breakpoint on. */
6372 static int
6374 {
6376 }
6378 static int
6380 {
6385 }
6387 static int
6389 {
6395 }
6397 static int
6399 {
6403 }
6405 static int
6407 {
6410 " template parameter %qD is not a parameter pack, but "
6414 }
6416 static int
6418 {
6421 " template argument %qE does not match "
6425 }
6427 static int
6429 {
6433 }
6435 static int
6437 {
6443 }
6445 static int
6447 {
6449 {
6454 else
6456 " deduced conflicting values for non-type parameter "
6458 }
6460 }
6462 static int
6464 {
6467 " variable-sized array type %qT is not "
6469 arg);
6471 }
6473 static int
6475 {
6479 arg);
6481 }
6483 static int
6485 {
6487 {
6493 else
6498 }
6500 }
6502 static int
6504 {
6506 }
6508 static int
6511 {
6513 }
6515 static int
6518 {
6524 }
6526 static int
6529 {
6532 {
6540 }
6542 }
6544 static int
6546 {
6549 " template parameters of a template template argument are "
6552 }
6554 static int
6556 {
6562 }
6564 static int
6566 {
6571 }
6573 /* Attempt to convert the non-type template parameter EXPR to the
6574 indicated TYPE. If the conversion is successful, return the
6575 converted value. If the conversion is unsuccessful, return
6576 NULL_TREE if we issued an error message, or error_mark_node if we
6577 did not. We issue error messages for out-and-out bad template
6578 parameters, but not simply because the conversion failed, since we
6579 might be just trying to do argument deduction. Both TYPE and EXPR
6580 must be non-dependent.
6582 The conversion follows the special rules described in
6583 [temp.arg.nontype], and it is much more strict than an implicit
6584 conversion.
6586 This function is called twice for each template argument (see
6587 lookup_template_class for a more accurate description of this
6588 problem). This means that we need to handle expressions which
6589 are not valid in a C++ source, but can be created from the
6590 first call (for instance, casts to perform conversions). These
6591 hacks can go away after we fix the double coercion problem. */
6593 static tree
6595 {
6596 tree expr_type;
6600 /* Detect immediately string literals as invalid non-type argument.
6601 This special-case is not needed for correctness (we would easily
6602 catch this later), but only to provide better diagnostic for this
6603 common user mistake. As suggested by DR 100, we do not mention
6604 linkage issues in the diagnostic as this is not the point. */
6605 /* FIXME we're making this OK. */
6607 {
6613 }
6615 /* Add the ADDR_EXPR now for the benefit of
6616 value_dependent_expression_p. */
6619 {
6623 }
6625 /* If we are in a template, EXPR may be non-dependent, but still
6626 have a syntactic, rather than semantic, form. For example, EXPR
6627 might be a SCOPE_REF, rather than the VAR_DECL to which the
6628 SCOPE_REF refers. Preserving the qualifying scope is necessary
6629 so that access checking can be performed when the template is
6630 instantiated -- but here we need the resolved form so that we can
6631 convert the argument. */
6643 /* If the argument is non-dependent, perform any conversions in
6644 non-dependent context as well. */
6652 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6653 to a non-type argument of "nullptr". */
6657 /* In C++11, integral or enumeration non-type template arguments can be
6658 arbitrary constant expressions. Pointer and pointer to
6659 member arguments can be general constant expressions that evaluate
6660 to a null value, but otherwise still need to be of a specific form. */
6662 {
6664 /* A PTRMEM_CST is already constant, and a valid template
6665 argument for a parameter of pointer to member type, we just want
6666 to leave it in that form rather than lower it to a
6670 {
6671 /* C++17: A template-argument for a non-type template-parameter shall
6672 be a converted constant expression (8.20) of the type of the
6673 template-parameter. */
6679 }
6681 {
6686 }
6687 }
6691 else
6694 /* HACK: Due to double coercion, we can get a
6695 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6696 which is the tree that we built on the first call (see
6697 below when coercing to reference to object or to reference to
6698 function). We just strip everything and get to the arg.
6699 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6700 for examples. */
6702 {
6708 {
6709 /* ??? Maybe we could use convert_from_reference here, but we
6710 would need to relax its constraints because the NOP_EXPR
6711 could actually change the type to something more cv-qualified,
6712 and this is not folded by convert_from_reference. */
6717 && (same_type_ignoring_top_level_qualifiers_p
6720 {
6723 }
6724 }
6725 }
6727 /* [temp.arg.nontype]/5, bullet 1
6729 For a non-type template-parameter of integral or enumeration type,
6730 integral promotions (_conv.prom_) and integral conversions
6731 (_conv.integral_) are applied. */
6733 {
6735 {
6740 }
6745 /* Notice that there are constant expressions like '4 % 0' which
6746 do not fold into integer constants. */
6749 {
6751 {
6755 else
6761 /* else cxx_constant_value complained but gave us
6762 a real constant, so go ahead. */
6764 {
6765 /* Some assemble time constant expressions like
6766 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6767 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6768 as we can emit them into .rodata initializers of
6769 variables, yet they can't fold into an INTEGER_CST at
6770 compile time. Refuse them here. */
6775 }
6776 }
6777 else
6779 }
6781 /* Avoid typedef problems. */
6784 }
6785 /* [temp.arg.nontype]/5, bullet 2
6787 For a non-type template-parameter of type pointer to object,
6788 qualification conversions (_conv.qual_) and the array-to-pointer
6789 conversion (_conv.array_) are applied. */
6791 {
6794 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6795 decay_conversion or an explicit cast. If it's a problematic cast,
6796 we'll complain about it below. */
6798 {
6803 {
6806 }
6807 }
6809 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6811 A template-argument for a non-type, non-template template-parameter
6812 shall be one of: [...]
6814 -- the name of a non-type template-parameter;
6815 -- the address of an object or function with external linkage, [...]
6816 expressed as "& id-expression" where the & is optional if the name
6817 refers to a function or array, or if the corresponding
6818 template-parameter is a reference.
6820 Here, we do not care about functions, as they are invalid anyway
6821 for a parameter of type pointer-to-object. */
6824 /* Non-type template parameters are OK. */
6825 ;
6829 {
6831 {
6834 "because %qD is a variable, not the address of "
6837 }
6839 {
6845 }
6846 /* Other values, like integer constants, might be valid
6847 non-type arguments of some other type. */
6849 }
6850 else
6851 {
6855 {
6860 }
6862 {
6868 }
6871 {
6876 }
6877 /* C++17: For a non-type template-parameter of reference or pointer
6878 type, the value of the constant expression shall not refer to (or
6879 for a pointer type, shall not be the address of):
6880 * a subobject (4.5),
6881 * a temporary object (15.2),
6882 * a string literal (5.13.5),
6883 * the result of a typeid expression (8.2.8), or
6884 * a predefined __func__ variable (11.4.1). */
6886 {
6889 decl);
6891 }
6895 {
6900 }
6902 {
6906 decl);
6908 }
6909 }
6916 }
6917 /* [temp.arg.nontype]/5, bullet 3
6919 For a non-type template-parameter of type reference to object, no
6920 conversions apply. The type referred to by the reference may be more
6921 cv-qualified than the (otherwise identical) type of the
6922 template-argument. The template-parameter is bound directly to the
6923 template-argument, which must be an lvalue. */
6925 {
6927 expr_type))
6931 {
6936 }
6939 {
6944 }
6946 /* [temp.arg.nontype]/1
6948 A template-argument for a non-type, non-template template-parameter
6949 shall be one of: [...]
6951 -- the address of an object or function with external linkage. */
6954 {
6957 {
6960 "because a reference variable does not have a constant "
6963 }
6964 }
6968 /* OK, dependent reference. We don't want to ask whether a DECL is
6970 else
6971 {
6973 {
6979 }
6981 /* DR 1155 allows internal linkage in C++11 and up. */
6984 {
6990 }
6993 }
6997 }
6998 /* [temp.arg.nontype]/5, bullet 4
7000 For a non-type template-parameter of type pointer to function, only
7001 the function-to-pointer conversion (_conv.func_) is applied. If the
7002 template-argument represents a set of overloaded functions (or a
7003 pointer to such), the matching function is selected from the set
7004 (_over.over_). */
7006 {
7007 /* If the argument is a template-id, we might not have enough
7008 context information to decay the pointer. */
7010 {
7014 }
7017 /* Null pointer values are OK in C++11. */
7023 }
7024 /* [temp.arg.nontype]/5, bullet 5
7026 For a non-type template-parameter of type reference to function, no
7027 conversions apply. If the template-argument represents a set of
7028 overloaded functions, the matching function is selected from the set
7029 (_over.over_). */
7031 {
7033 {
7035 {
7040 }
7042 }
7047 }
7048 /* [temp.arg.nontype]/5, bullet 6
7050 For a non-type template-parameter of type pointer to member function,
7051 no conversions apply. If the template-argument represents a set of
7052 overloaded member functions, the matching member function is selected
7053 from the set (_over.over_). */
7055 {
7060 /* [temp.arg.nontype] bullet 1 says the pointer to member
7061 expression must be a pointer-to-member constant. */
7066 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7067 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7070 }
7071 /* [temp.arg.nontype]/5, bullet 7
7073 For a non-type template-parameter of type pointer to data member,
7074 qualification conversions (_conv.qual_) are applied. */
7076 {
7077 /* [temp.arg.nontype] bullet 1 says the pointer to member
7078 expression must be a pointer-to-member constant. */
7086 }
7088 {
7090 {
7095 }
7097 }
7098 /* A template non-type parameter must be one of the above. */
7099 else
7102 /* Sanity check: did we actually convert the argument to the
7103 right type? */
7107 }
7109 /* Subroutine of coerce_template_template_parms, which returns 1 if
7110 PARM_PARM and ARG_PARM match using the rule for the template
7111 parameters of template template parameters. Both PARM and ARG are
7112 template parameters; the rest of the arguments are the same as for
7113 coerce_template_template_parms.
7114 */
7115 static int
7117 tree arg,
7118 tsubst_flags_t complain,
7119 tree in_decl,
7120 tree outer_args)
7121 {
7130 {
7132 /* We encounter instantiations of templates like
7133 template <template <template <class> class> class TT>
7134 class C; */
7135 {
7142 }
7143 /* Fall through. */
7148 /* Argument is a parameter pack but parameter is not. */
7153 /* The tsubst call is used to handle cases such as
7155 template <int> class C {};
7156 template <class T, template <T> class TT> class D {};
7157 D<int, C> d;
7159 i.e. the parameter list of TT depends on earlier parameters. */
7161 {
7166 }
7170 /* Argument is a parameter pack but parameter is not. */
7177 }
7180 }
7182 /* Coerce template argument list ARGLIST for use with template
7183 template-parameter TEMPL. */
7185 static tree
7187 tsubst_flags_t complain)
7188 {
7189 /* Consider an example where a template template parameter declared as
7191 template <class T, class U = std::allocator<T> > class TT
7193 The template parameter level of T and U are one level larger than
7194 of TT. To proper process the default argument of U, say when an
7195 instantiation `TT<int>' is seen, we need to build the full
7196 arguments containing {int} as the innermost level. Outer levels,
7197 available when not appearing as default template argument, can be
7198 obtained from the arguments of the enclosing template.
7200 Suppose that TT is later substituted with std::vector. The above
7201 instantiation is `TT<int, std::allocator<T> >' with TT at
7202 level 1, and T at level 2, while the template arguments at level 1
7203 becomes {std::vector} and the inner level 2 is {int}. */
7207 {
7209 /* We want arguments for the partial specialization, not arguments for
7210 the primary template. */
7212 else
7214 }
7216 {
7217 /* This is an argument of the current template, so we haven't set
7218 DECL_CONTEXT yet. */
7219 tree relevant_template_parms;
7221 /* Parameter levels that are greater than the level of the given
7222 template template parm are irrelevant. */
7229 }
7236 complain,
7239 }
7241 /* A cache of template template parameters with match-all default
7242 arguments. */
7244 static void
7246 {
7250 }
7251 static tree
7253 {
7258 }
7260 /* T is a bound template template-parameter. Copy its arguments into default
7261 arguments of the template template-parameter's template parameters. */
7263 static tree
7265 {
7288 {
7291 {
7294 }
7295 }
7299 }
7301 /* ARG is a bound potential template template-argument, and PARGS is a list
7302 of arguments for the corresponding template template-parameter. Adjust
7303 PARGS as appropriate for application to ARG's template, and if ARG is a
7304 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7305 arguments to the template template parameter. */
7307 static tree
7309 {
7313 {
7314 /* When comparing two template template-parameters in partial ordering,
7315 rewrite the one currently being used as an argument to have default
7316 arguments for all parameters. */
7322 }
7323 else
7324 {
7325 tree aparms
7330 }
7333 }
7335 /* Subroutine of unify for the case when PARM is a
7336 BOUND_TEMPLATE_TEMPLATE_PARM. */
7338 static int
7341 {
7345 /* The template template parm might be variadic and the argument
7346 not, so flatten both argument lists. */
7351 {
7352 /* In keeping with P0522R0, adjust P's template arguments
7353 to apply to A's template; then flatten it again. */
7362 /* If the P0522 adjustment eliminated a pack expansion, deduce
7363 empty packs. */
7369 }
7370 else
7371 {
7372 /* Deduce arguments T, i from TT<T> or TT<i>.
7373 We check each element of PARMVEC and ARGVEC individually
7374 rather than the whole TREE_VEC since they can have
7375 different number of elements, which is allowed under N2555. */
7379 /* Check if the parameters end in a pack, making them
7380 variadic. */
7387 /* If the template argument list of P contains a pack
7388 expansion that is not the last template argument, the
7389 entire template argument list is a non-deduced
7390 context. */
7408 DEDUCE_EXACT,
7411 }
7414 }
7416 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7417 template template parameters. Both PARM_PARMS and ARG_PARMS are
7418 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7419 or PARM_DECL.
7421 Consider the example:
7422 template <class T> class A;
7423 template<template <class U> class TT> class B;
7425 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7426 the parameters to A, and OUTER_ARGS contains A. */
7428 static int
7430 tree arg_parms,
7431 tsubst_flags_t complain,
7432 tree in_decl,
7433 tree outer_args)
7434 {
7446 {
7447 /* P0522R0: A template template-parameter P is at least as specialized as
7448 a template template-argument A if, given the following rewrite to two
7449 function templates, the function template corresponding to P is at
7450 least as specialized as the function template corresponding to A
7451 according to the partial ordering rules for function templates
7452 ([temp.func.order]). Given an invented class template X with the
7453 template parameter list of A (including default arguments):
7455 * Each of the two function templates has the same template parameters,
7456 respectively, as P or A.
7458 * Each function template has a single function parameter whose type is
7459 a specialization of X with template arguments corresponding to the
7460 template parameters from the respective function template where, for
7461 each template parameter PP in the template parameter list of the
7462 function template, a corresponding template argument AA is formed. If
7463 PP declares a parameter pack, then AA is the pack expansion
7464 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7466 If the rewrite produces an invalid type, then P is not at least as
7467 specialized as A. */
7469 /* So coerce P's args to apply to A's parms, and then deduce between A's
7470 args and the converted args. If that succeeds, A is at least as
7471 specialized as P, so they match.*/
7478 {
7484 }
7485 }
7487 /* Determine whether we have a parameter pack at the end of the
7488 template template parameter's template parameter list. */
7490 {
7497 {
7511 }
7512 }
7518 /* Check all of the template parameters except the parameter pack at
7519 the end (if any). */
7521 {
7530 outer_args))
7533 }
7536 {
7537 /* Check each of the template parameters in the template
7538 argument against the template parameter pack at the end of
7539 the template template parameter. */
7546 {
7553 outer_args))
7555 }
7556 }
7559 }
7561 /* Verifies that the deduced template arguments (in TARGS) for the
7562 template template parameters (in TPARMS) represent valid bindings,
7563 by comparing the template parameter list of each template argument
7564 to the template parameter list of its corresponding template
7565 template parameter, in accordance with DR150. This
7566 routine can only be called after all template arguments have been
7567 deduced. It will return TRUE if all of the template template
7568 parameter bindings are okay, FALSE otherwise. */
7569 bool
7571 {
7575 /* We're dealing with template parms in this process. */
7581 {
7586 {
7591 {
7592 /* Look inside the argument pack. */
7595 }
7598 {
7602 /* Extract the next argument from the argument
7603 pack. */
7607 /* Look at the pattern of the pack expansion. */
7610 /* Extract the template parameters from the template
7611 argument. */
7617 /* Verify that we can coerce the template template
7618 parameters from the template argument to the template
7619 parameter. This requires an exact match. */
7621 && !coerce_template_template_parms
7623 targ_parms,
7624 tf_none,
7625 tparm,
7626 targs))
7627 {
7630 }
7631 }
7632 }
7633 }
7635 out:
7639 }
7641 /* Since type attributes aren't mangled, we need to strip them from
7642 template type arguments. */
7644 static tree
7646 {
7656 }
7658 /* And from inside dependent non-type arguments like sizeof(Type). */
7660 static tree
7662 {
7672 }
7674 // A template declaration can be substituted for a constrained
7675 // template template parameter only when the argument is more
7676 // constrained than the parameter.
7677 static bool
7679 {
7682 /* For now, allow constrained template template arguments
7683 and unconstrained template template parameters. */
7689 // If the template parameter is constrained, we need to rewrite its
7690 // constraints in terms of the ARG's template parameters. This ensures
7691 // that all of the template parameter types will have the same depth.
7692 //
7693 // Note that this is only valid when coerce_template_template_parm is
7694 // true for the innermost template parameters of PARM and ARG. In other
7695 // words, because coercion is successful, this conversion will be valid.
7697 {
7704 }
7707 }
7709 // Convert a placeholder argument into a binding to the original
7710 // parameter. The original parameter is saved as the TREE_TYPE of
7711 // ARG.
7714 {
7717 }
7719 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7720 because one of them is dependent. But we need to represent the
7721 conversion for the benefit of cp_tree_equal. */
7723 static tree
7725 {
7726 /* Auto parms get no conversion. */
7729 /* We don't need or want to add this conversion now if we're going to use the
7730 argument for deduction. */
7742 }
7744 /* Convert the indicated template ARG as necessary to match the
7745 indicated template PARM. Returns the converted ARG, or
7746 error_mark_node if the conversion was unsuccessful. Error and
7747 warning messages are issued under control of COMPLAIN. This
7748 conversion is for the Ith parameter in the parameter list. ARGS is
7749 the full set of template arguments deduced so far. */
7751 static tree
7753 tree arg,
7754 tree args,
7755 tsubst_flags_t complain,
7757 tree in_decl)
7758 {
7759 tree orig_arg;
7760 tree val;
7766 /* Trivially convert placeholders. */
7775 {
7776 /* The template argument was the name of some
7777 member function. That's usually
7778 invalid, but static members are OK. In any
7779 case, grab the underlying fields/functions
7780 and issue an error later if required. */
7783 }
7791 /* When determining whether an argument pack expansion is a template,
7792 look at the pattern. */
7796 /* Deal with an injected-class-name used as a template template arg. */
7798 {
7801 {
7811 }
7812 }
7814 is_tmpl_type =
7830 {
7832 {
7836 }
7839 "to refer to a type member of a template parameter, "
7844 typename_type,
7845 complain);
7848 }
7850 {
7852 {
7854 {
7866 else
7869 }
7870 }
7872 }
7874 {
7876 {
7883 else
7886 }
7888 }
7891 /* We already did the appropriate conversion when packing args. */
7894 {
7896 {
7898 /* The number of argument required is not known yet.
7899 Just accept it for now. */
7901 else
7902 {
7904 tree argparm;
7906 /* Strip alias templates that are equivalent to another
7907 template. */
7913 args))
7914 {
7917 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7918 TEMPLATE_DECL. */
7920 {
7925 }
7926 }
7927 else
7928 {
7930 {
7937 }
7940 }
7942 // Check that the constraints are compatible before allowing the
7943 // substitution.
7946 {
7948 {
7954 }
7956 }
7957 }
7958 }
7959 else
7961 /* We only form one instance of each template specialization.
7962 Therefore, if we use a non-canonical variant (i.e., a
7963 typedef), any future messages referring to the type will use
7964 the typedef, which is confusing if those future uses do not
7965 themselves also use the typedef. */
7968 }
7969 else
7970 {
7975 /* We don't have enough levels of args to do any substitution. This
7978 {
7982 }
7983 else
7991 /* We used to call digest_init here. However, digest_init
7992 will report errors, which we don't want when complain
7993 is zero. More importantly, digest_init will try too
7994 hard to convert things: for example, `0' should not be
7995 converted to pointer type at this point according to
7996 the standard. Accepting this is not merely an
7997 extension, since deciding whether or not these
7998 conversions can occur is part of determining which
7999 function template to call, or whether a given explicit
8000 argument specification is valid. */
8002 else
8003 {
8006 }
8016 {
8017 /* Reject template arguments that are references to built-in
8018 functions with no library fallbacks. */
8027 }
8030 {
8031 /* Strip typedefs from the SCOPE_REF. */
8034 complain);
8037 }
8038 }
8041 }
8043 /* Coerces the remaining template arguments in INNER_ARGS (from
8044 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8045 Returns the coerced argument pack. PARM_IDX is the position of this
8046 parameter in the template parameter list. ARGS is the original
8047 template argument list. */
8048 static tree
8051 tree args,
8052 tree inner_args,
8054 tree new_args,
8056 tree in_decl,
8057 tsubst_flags_t complain)
8058 {
8061 tree packed_args;
8062 tree argument_pack;
8069 {
8070 /* When the template parameter is a non-type template parameter pack
8071 or template template parameter pack whose type or template
8072 parameters use parameter packs, we know exactly how many arguments
8073 we are looking for. Build a vector of the instantiated decls for
8074 these template parameters in PACKED_PARMS. */
8075 /* We can't use make_pack_expansion here because it would interpret a
8076 _DECL as a use rather than a declaration. */
8090 /* If we're doing a partial instantiation of a member template,
8091 verify that all of the types used for the non-type
8092 template parameter pack are, in fact, valid for non-type
8093 template parameters. */
8096 {
8099 {
8103 }
8104 /* We don't know how many args we have yet, just
8105 use the unconverted ones for now. */
8107 }
8110 }
8111 /* Check if we have a placeholder pack, which indicates we're
8112 in the context of a introduction list. In that case we want
8113 to match this pack to the single placeholder. */
8117 {
8120 }
8121 else
8124 /* Convert the remaining arguments, which will be a part of the
8125 parameter pack "parm". */
8128 {
8134 {
8135 /* Once we've packed as many args as we have types, stop. */
8139 /* We don't know how many args we have yet, just
8140 use the unconverted ones for now. */
8142 else
8144 }
8147 {
8150 }
8151 else
8154 in_decl);
8158 }
8162 {
8167 }
8172 else
8173 {
8176 }
8183 }
8185 /* Returns the number of pack expansions in the template argument vector
8186 ARGS. */
8188 static int
8190 {
8195 {
8199 }
8201 }
8203 /* Convert all template arguments to their appropriate types, and
8204 return a vector containing the innermost resulting template
8205 arguments. If any error occurs, return error_mark_node. Error and
8206 warning messages are issued under control of COMPLAIN.
8208 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8209 for arguments not specified in ARGS. Otherwise, if
8210 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8211 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8212 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8213 ARGS. */
8215 static tree
8217 tree args,
8218 tree in_decl,
8219 tsubst_flags_t complain,
8222 {
8224 tree orig_inner_args;
8225 tree inner_args;
8226 tree new_args;
8227 tree new_inner_args;
8231 /* When used as a boolean value, indicates whether this is a
8232 variadic template parameter list. Since it's an int, we can also
8233 subtract it from nparms to get the number of non-variadic
8234 parameters. */
8239 /* Adjustment to nparms for fixed parameter packs. */
8244 /* Likewise for parameters with default arguments. */
8252 /* Determine if there are any parameter packs or default arguments. */
8254 {
8262 }
8265 /* If there are no parameters that follow a parameter pack, we need to
8266 expand any argument packs so that we can deduce a parameter pack from
8267 some non-packed args followed by an argument pack, as in variadic85.C.
8268 If there are such parameters, we need to leave argument packs intact
8269 so the arguments are assigned properly. This can happen when dealing
8270 with a nested class inside a partial specialization of a class
8271 template, as in variadic92.C, or when deducing a template parameter pack
8272 from a sub-declarator, as in variadic114.C. */
8276 /* Count any pack expansion args. */
8282 && require_all_args
8283 && !variadic_args_p
8284 && (!use_default_args
8287 {
8288 bad_nargs:
8290 {
8292 {
8296 }
8297 else
8304 }
8307 }
8308 /* We can't pass a pack expansion to a non-pack parameter of an alias
8309 template (DR 1430). */
8313 && variadic_args_p
8315 {
8317 {
8319 {
8325 {
8328 "pack expansion argument for non-pack parameter "
8330 else
8332 "pack expansion argument for non-pack parameter "
8336 }
8337 }
8339 found:;
8340 }
8342 }
8344 /* We need to evaluate the template arguments, even though this
8345 template-id may be nested within a "sizeof". */
8354 {
8355 tree arg;
8356 tree parm;
8358 /* Get the Ith template parameter. */
8362 {
8365 }
8367 /* Calculate the next argument. */
8370 else
8375 {
8376 /* Some arguments will be placed in the
8377 template parameter pack PARM. */
8384 {
8385 /* We don't know how many args we have yet, just use the
8386 unconverted (and still packed) ones for now. */
8390 }
8394 /* Store this argument. */
8396 {
8397 lost++;
8398 /* We are done with all of the arguments. */
8401 }
8402 else
8403 {
8407 {
8410 }
8411 }
8414 }
8416 {
8418 {
8419 /* "If every valid specialization of a variadic template
8420 requires an empty template parameter pack, the template is
8421 ill-formed, no diagnostic required." So check that the
8422 pattern works with this parameter. */
8427 in_decl);
8429 {
8434 }
8436 /* Recover from missing typename. */
8440 /* We don't know how many args we have yet, just
8441 use the unconverted ones for now. */
8445 }
8446 }
8448 {
8449 /* There must be a default arg in this case. */
8452 /* The position of the first default template argument,
8453 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8454 Record that. */
8458 }
8459 else
8463 {
8466 }
8468 {
8469 /* This can occur if there was an error in the template
8470 parameter list itself (which we would already have
8471 reported) that we are trying to recover from, e.g., a class
8472 template with a parameter list such as
8473 template<typename..., typename> (cpp0x/variadic150.C). */
8476 /* This can also happen with a fixed parameter pack (71834). */
8479 }
8480 else
8486 lost++;
8488 }
8493 {
8494 /* If we had fixed parameter packs, we didn't know how many arguments we
8495 actually needed earlier; now we do. */
8499 }
8502 {
8503 /* We had some pack expansion arguments that will only work if the packs
8504 are empty, but wait until instantiation time to complain.
8505 See variadic-ttp3.C. */
8515 }
8518 {
8521 }
8528 }
8530 /* Convert all template arguments to their appropriate types, and
8531 return a vector containing the innermost resulting template
8532 arguments. If any error occurs, return error_mark_node. Error and
8533 warning messages are not issued.
8535 Note that no function argument deduction is performed, and default
8536 arguments are used to fill in unspecified arguments. */
8537 tree
8539 {
8541 }
8543 /* Convert all template arguments to their appropriate type, and
8544 instantiate default arguments as needed. This returns a vector
8545 containing the innermost resulting template arguments, or
8546 error_mark_node if unsuccessful. */
8547 tree
8549 tsubst_flags_t complain)
8550 {
8552 }
8554 /* Like coerce_template_parms. If PARMS represents all template
8555 parameters levels, this function returns a vector of vectors
8556 representing all the resulting argument levels. Note that in this
8557 case, only the innermost arguments are coerced because the
8558 outermost ones are supposed to have been coerced already.
8560 Otherwise, if PARMS represents only (the innermost) vector of
8561 parameters, this function returns a vector containing just the
8562 innermost resulting arguments. */
8564 static tree
8566 tree args,
8567 tree in_decl,
8568 tsubst_flags_t complain,
8571 {
8574 tree coerced_args;
8577 {
8579 tree level;
8585 {
8586 tree l;
8590 require_all_args,
8591 use_default_args);
8592 else
8599 }
8600 }
8601 else
8604 require_all_args,
8605 use_default_args);
8607 }
8609 /* Returns 1 if template args OT and NT are equivalent. */
8611 int
8613 {
8622 /* For member templates */
8631 {
8648 }
8652 {
8655 /* Don't treat an alias template specialization with dependent
8656 arguments as equivalent to its underlying type when used as a
8657 template argument; we need them to be distinct so that we
8658 substitute into the specialization arguments at instantiation
8659 time. And aliases can't be equivalent without being ==, so
8660 we don't need to look any deeper.
8662 During partial ordering, however, we need to treat them normally so
8663 that we can order uses of the same alias with different
8664 cv-qualification (79960). */
8668 else
8670 }
8673 else
8674 {
8675 /* Try to treat a template non-type argument that has been converted
8676 to the parameter type as equivalent to one that hasn't yet. */
8689 }
8690 }
8692 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8693 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8694 NEWARG_PTR with the offending arguments if they are non-NULL. */
8696 int
8700 {
8713 {
8718 {
8724 }
8725 }
8727 }
8731 {
8733 }
8735 /* Implement a freelist interface for objects of type T.
8737 Head is a separate object, rather than a regular member, so that we
8738 can define it as a GTY deletable pointer, which is highly
8739 desirable. A data member could be declared that way, but then the
8740 containing object would implicitly get GTY((user)), which would
8741 prevent us from instantiating freelists as global objects.
8742 Although this way we can create freelist global objects, they're
8743 such thin wrappers that instantiating temporaries at every use
8744 loses nothing and saves permanent storage for the freelist object.
8746 Member functions next, anew, poison and reinit have default
8747 implementations that work for most of the types we're interested
8748 in, but if they don't work for some type, they should be explicitly
8749 specialized. See the comments before them for requirements, and
8750 the example specializations for the tree_list_freelist. */
8752 class freelist
8753 {
8754 /* Return the next object in a chain. We could just do type
8755 punning, but if we access the object with its underlying type, we
8756 avoid strict-aliasing trouble. This needs only work between
8757 poison and reinit. */
8760 /* Return a newly allocated, uninitialized or minimally-initialized
8761 object of type T. Any initialization performed by anew should
8762 either remain across the life of the object and the execution of
8763 poison, or be redone by reinit. */
8766 /* Optionally scribble all over the bits holding the object, so that
8767 they become (mostly?) uninitialized memory. This is called while
8768 preparing to make the object part of the free list. */
8773 #ifdef ENABLE_GC_CHECKING
8774 /* Poison the data, to indicate the data is garbage. */
8777 #endif
8778 /* Let valgrind know the object is free. */
8781 /* Let valgrind know the next portion of the object is available,
8782 but uninitialized. */
8784 }
8786 /* Bring an object that underwent at least one lifecycle after anew
8787 and before the most recent free and poison, back to a usable
8788 state, reinitializing whatever is needed for it to be
8789 functionally equivalent to an object just allocated and returned
8790 by anew. This may poison or clear the next field, used by
8791 freelist housekeeping after poison was called. */
8795 #ifdef ENABLE_GC_CHECKING
8797 #endif
8798 /* Let valgrind know the entire object is available, but
8799 uninitialized. */
8801 }
8803 /* Reference a GTY-deletable pointer that points to the first object
8804 in the free list proper. */
8807 /* Construct a freelist object chaining objects off of HEAD. */
8810 /* Add OBJ to the free object list. The former head becomes OBJ's
8811 successor. */
8813 {
8817 }
8819 /* Take an object from the free list, if one is available, or
8820 allocate a new one. Objects taken from the free list should be
8821 regarded as filled with garbage, except for bits that are
8822 configured to be preserved across free and alloc. */
8824 {
8826 {
8831 }
8832 else
8834 }
8835 };
8837 /* Explicitly specialize the interfaces for freelist<tree_node>: we
8838 want to allocate a TREE_LIST using the usual interface, and ensure
8839 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
8840 build_tree_list logic in reinit, so this could go out of sync. */
8844 {
8846 }
8848 inline tree
8850 {
8852 }
8856 {
8862 #ifdef ENABLE_GC_CHECKING
8865 /* Poison the data, to indicate the data is garbage. */
8868 #endif
8869 /* Let valgrind know the object is free. */
8871 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
8875 #ifdef ENABLE_GC_CHECKING
8877 /* Keep TREE_CHAIN functional. */
8879 #else
8881 #endif
8882 }
8886 {
8889 #ifdef ENABLE_GC_CHECKING
8893 #endif
8895 /* Let valgrind know the entire object is available, but
8896 uninitialized. */
8899 #ifdef ENABLE_GC_CHECKING
8901 #else
8903 #endif
8904 }
8906 /* Point to the first object in the TREE_LIST freelist. */
8908 /* Return the/an actual TREE_LIST freelist. */
8911 {
8913 }
8915 /* Point to the first object in the tinst_level freelist. */
8917 /* Return the/an actual tinst_level freelist. */
8920 {
8922 }
8924 /* Point to the first object in the pending_template freelist. */
8926 /* Return the/an actual pending_template freelist. */
8929 {
8931 }
8933 /* Build the TREE_LIST object out of a split list, store it
8934 permanently, and return it. */
8935 tree
8937 {
8946 }
8950 /* Increment OBJ's refcount unless it is already infinite. */
8953 {
8957 }
8959 /* Release storage for OBJ and node, if it's a TREE_LIST. */
8960 void
8962 {
8966 }
8968 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
8969 OBJ's DECL and OBJ, and start over with the tinst_level object that
8970 used to be referenced by OBJ's NEXT. */
8971 static void
8973 {
8977 {
8981 }
8982 }
8984 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
8985 and of the former PTR. Omitting the second argument is equivalent
8986 to passing (T*)NULL; this is allowed because passing the
8987 zero-valued integral constant NULL confuses type deduction and/or
8988 overload resolution. */
8990 static void
8992 {
8996 }
8998 static void
9000 {
9010 /* We are called both from instantiate_decl, where we've already had a
9011 tinst_level pushed, and instantiate_template, where we haven't.
9012 Compensate. */
9014 level = !current_tinst_level
9026 else
9035 }
9038 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9039 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9040 documentation for TEMPLATE_ID_EXPR. */
9042 tree
9044 {
9045 tree type;
9053 {
9056 }
9059 {
9061 unknown_type_node,
9063 arglist);
9065 }
9072 }
9074 /* Within the scope of a template class S<T>, the name S gets bound
9075 (in build_self_reference) to a TYPE_DECL for the class, not a
9076 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9077 or one of its enclosing classes, and that type is a template,
9078 return the associated TEMPLATE_DECL. Otherwise, the original
9079 DECL is returned.
9081 Also handle the case when DECL is a TREE_LIST of ambiguous
9082 injected-class-names from different bases. */
9084 tree
9086 {
9090 /* DR 176: A lookup that finds an injected-class-name (10.2
9091 [class.member.lookup]) can result in an ambiguity in certain cases
9092 (for example, if it is found in more than one base class). If all of
9093 the injected-class-names that are found refer to specializations of
9094 the same class template, and if the name is followed by a
9095 template-argument-list, the reference refers to the class template
9096 itself and not a specialization thereof, and is not ambiguous. */
9098 {
9101 {
9107 }
9110 else
9112 }
9118 }
9120 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9121 parameters, find the desired type.
9123 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9125 IN_DECL, if non-NULL, is the template declaration we are trying to
9126 instantiate.
9128 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9129 the class we are looking up.
9131 Issue error and warning messages under control of COMPLAIN.
9133 If the template class is really a local class in a template
9134 function, then the FUNCTION_CONTEXT is the function in which it is
9135 being instantiated.
9137 ??? Note that this function is currently called *twice* for each
9138 template-id: the first time from the parser, while creating the
9139 incomplete type (finish_template_type), and the second type during the
9140 real instantiation (instantiate_template_class). This is surely something
9141 that we want to avoid. It also causes some problems with argument
9142 coercion (see convert_nontype_argument for more information on this). */
9144 static tree
9147 {
9149 tree t;
9152 spec_entry elt;
9153 hashval_t hash;
9156 {
9160 else
9161 {
9168 }
9171 }
9173 {
9176 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9177 an implicit typename for the second A. Deal with it. */
9182 {
9185 }
9186 }
9189 {
9192 }
9194 {
9198 }
9200 {
9203 }
9205 /* Issue an error message if we didn't find a template. */
9207 {
9211 }
9214 /* Make sure it's a user visible template, if it was named by
9215 the user. */
9218 {
9220 {
9224 }
9226 }
9230 /* An alias that just changes the name of a template is equivalent to the
9231 other template, so if any of the arguments are pack expansions, strip
9232 the alias to avoid problems with a pack expansion passed to a non-pack
9233 alias template parameter (DR 1430). */
9238 {
9239 tree parm;
9248 }
9249 else
9250 {
9252 tree gen_tmpl;
9253 tree type_decl;
9261 /* An error occurred while building the template TEMPL, and a
9262 diagnostic has most certainly been emitted for that
9263 already. Let's propagate that error. */
9272 {
9273 /* We've been given an incomplete set of template arguments.
9274 For example, given:
9276 template <class T> struct S1 {
9277 template <class U> struct S2 {};
9278 template <class U> struct S2<U*> {};
9279 };
9281 we will be called with an ARGLIST of `U*', but the
9282 TEMPLATE will be `template <class T> template
9283 <class U> struct S1<T>::S2'. We must fill in the missing
9284 arguments. */
9288 }
9290 /* Now we should have enough arguments. */
9293 /* From here on, we're only interested in the most general
9294 template. */
9296 /* Calculate the BOUND_ARGS. These will be the args that are
9297 actually tsubst'd into the definition to create the
9298 instantiation. */
9300 complain,
9305 /* We were unable to bind the arguments. */
9308 /* In the scope of a template class, explicit references to the
9309 template class refer to the type of the template, not any
9310 instantiation of it. For example, in:
9312 template <class T> class C { void f(C<T>); }
9314 the `C<T>' is just the same as `C'. Outside of the
9315 class, however, such a reference is an instantiation. */
9319 {
9324 }
9326 /* If we already have this specialization, return it. */
9336 /* If the the template's constraints are not satisfied,
9337 then we cannot form a valid type.
9339 Note that the check is deferred until after the hash
9340 lookup. This prevents redundant checks on previously
9341 instantiated specializations. */
9343 {
9345 {
9348 }
9350 }
9354 /* If the deduced arguments are invalid, then the binding
9355 failed. */
9359 complain))
9366 {
9371 }
9381 /* Create the type. */
9383 {
9384 /* The user referred to a specialization of an alias
9385 template represented by GEN_TMPL.
9387 [temp.alias]/2 says:
9389 When a template-id refers to the specialization of an
9390 alias template, it is equivalent to the associated
9391 type obtained by substitution of its
9392 template-arguments for the template-parameters in the
9393 type-id of the alias template. */
9396 /* Note that the call above (by indirectly calling
9397 register_specialization in tsubst_decl) registers the
9398 TYPE_DECL representing the specialization of the alias
9399 template. So next time someone substitutes ARGLIST for
9400 the template parms into the alias template (GEN_TMPL),
9401 she'll get that TYPE_DECL back. */
9405 }
9407 {
9409 {
9420 }
9421 else
9422 {
9423 /* We don't want to call start_enum for this type, since
9424 the values for the enumeration constants may involve
9425 template parameters. And, no one should be interested
9426 in the enumeration constants for such a type. */
9429 }
9433 }
9435 {
9436 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9437 instantiated here. */
9445 /* A local class. Make sure the decl gets registered properly. */
9452 /* This instantiation is another name for the primary
9453 template type. Set the TYPE_CANONICAL field
9454 appropriately. */
9457 /* Some of the template arguments require structural
9458 equality testing, so this template class requires
9459 structural equality testing. */
9461 }
9462 else
9465 /* If we called start_enum or pushtag above, this information
9466 will already be set up. */
9468 {
9475 }
9476 else
9480 {
9486 {
9489 }
9490 }
9494 {
9498 {
9499 tree attributes
9507 }
9508 }
9510 /* Let's consider the explicit specialization of a member
9511 of a class template specialization that is implicitly instantiated,
9512 e.g.:
9513 template<class T>
9514 struct S
9515 {
9516 template<class U> struct M {}; //#0
9517 };
9519 template<>
9520 template<>
9521 struct S<int>::M<char> //#1
9522 {
9523 int i;
9524 };
9525 [temp.expl.spec]/4 says this is valid.
9527 In this case, when we write:
9528 S<int>::M<char> m;
9530 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9531 the one of #0.
9533 When we encounter #1, we want to store the partial instantiation
9534 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9536 For all cases other than this "explicit specialization of member of a
9537 class template", we just want to store the most general template into
9538 the CLASSTYPE_TI_TEMPLATE of M.
9540 This case of "explicit specialization of member of a class template"
9541 only happens when:
9542 1/ the enclosing class is an instantiation of, and therefore not
9543 the same as, the context of the most general template, and
9544 2/ we aren't looking at the partial instantiation itself, i.e.
9545 the innermost arguments are not the same as the innermost parms of
9546 the most general template.
9548 So it's only when 1/ and 2/ happens that we want to use the partial
9549 instantiation of the member template in lieu of its most general
9550 template. */
9554 /* the enclosing class must be an instantiation... */
9557 {
9561 tree partial_inst_args =
9568 use_partial_inst_tmpl =
9569 /*...and we must not be looking at the partial instantiation
9570 itself. */
9572 partial_inst_args);
9573 }
9576 /* This case is easy; there are no member templates involved. */
9578 else
9579 {
9580 /* This is a full instantiation of a member template. Find
9581 the partial instantiation of which this is an instance. */
9583 /* Temporarily reduce by one the number of levels in the ARGLIST
9584 so as to avoid comparing the last set of arguments. */
9588 /* FOUND is either a proper class type, or an alias
9589 template specialization. In the later case, it's a
9590 TYPE_DECL, resulting from the substituting of arguments
9591 for parameters in the TYPE_DECL of the alias template
9592 done earlier. So be careful while getting the template
9593 of FOUND. */
9595 ? found
9599 }
9601 // Build template info for the new specialization.
9610 /* Note this use of the partial instantiation so we can check it
9611 later in maybe_process_partial_specialization. */
9618 /* Now that the type has been registered on the instantiations
9619 list, we set up the enumerators. Because the enumeration
9620 constants may involve the enumeration type itself, we make
9621 sure to register the type first, and then create the
9622 constants. That way, doing tsubst_expr for the enumeration
9623 constants won't result in recursive calls here; we'll find
9624 the instantiation and exit above. */
9628 /* If the type makes use of template parameters, the
9629 code that generates debugging information will crash. */
9632 /* Possibly limit visibility based on template args. */
9639 }
9640 }
9642 /* Wrapper for lookup_template_class_1. */
9644 tree
9647 {
9648 tree ret;
9654 }
9656 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9658 tree
9660 {
9661 /* The type of the expression is NULL_TREE since the template-id could refer
9662 to an explicit or partial specialization. */
9665 /* Except that concepts are always bool. */
9668 }
9670 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9672 tree
9674 {
9678 /* We never want to return a VAR_DECL for a variable concept, since they
9679 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9694 {
9696 {
9699 }
9701 }
9703 /* If a template-id refers to a specialization of a variable
9704 concept, then the expression is true if and only if the
9705 concept's constraints are satisfied by the given template
9706 arguments.
9708 NOTE: This is an extension of Concepts Lite TS that
9709 allows constraints to be used in expressions. */
9711 {
9714 }
9717 }
9719 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9720 TARGS template args, and instantiate it if it's not dependent. */
9722 tree
9724 tsubst_flags_t complain)
9725 {
9728 {
9731 }
9734 }
9736 \f
9737 struct pair_fn_data
9738 {
9739 tree_fn_t fn;
9740 tree_fn_t any_fn;
9742 /* True when we should also visit template parameters that occur in
9743 non-deduced contexts. */
9746 };
9748 /* Called from for_each_template_parm via walk_tree. */
9750 static tree
9752 {
9759 #define WALK_SUBTREE(NODE) \
9760 do \
9761 { \
9762 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9763 pfd->include_nondeduced_p, \
9764 pfd->any_fn); \
9765 if (result) goto out; \
9766 } \
9767 while (0)
9777 {
9781 /* Fall through. */
9787 else
9797 /* Since we're not going to walk subtrees, we have to do this
9798 explicitly here. */
9800 /* Fall through. */
9803 /* Check the return type. */
9806 /* Check the parameter types. Since default arguments are not
9807 instantiated until they are needed, the TYPE_ARG_TYPES may
9808 contain expressions that involve template parameters. But,
9809 no-one should be looking at them yet. And, once they're
9810 instantiated, they don't contain template parameters, so
9811 there's no point in looking at them then, either. */
9812 {
9813 tree parm;
9818 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9819 want walk_tree walking into them itself. */
9821 }
9824 {
9828 }
9847 /* Fall through. */
9859 /* Record template parameters such as `T' inside `TT<T>'. */
9861 /* Fall through. */
9873 /* A template template parameter is encountered. */
9877 /* Already substituted template template parameter */
9882 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9883 partial instantiation. */
9895 /* If there's no type, then this thing must be some expression
9896 involving template parameters. */
9918 }
9920 #undef WALK_SUBTREE
9922 /* We didn't find any template parameters we liked. */
9923 out:
9925 }
9927 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9928 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9929 call FN with the parameter and the DATA.
9930 If FN returns nonzero, the iteration is terminated, and
9931 for_each_template_parm returns 1. Otherwise, the iteration
9932 continues. If FN never returns a nonzero value, the value
9933 returned by for_each_template_parm is 0. If FN is NULL, it is
9934 considered to be the function which always returns 1.
9936 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9937 parameters that occur in non-deduced contexts. When false, only
9938 visits those template parameters that can be deduced. */
9940 static tree
9944 tree_fn_t any_fn)
9945 {
9947 tree result;
9949 /* Set up. */
9955 /* Walk the tree. (Conceptually, we would like to walk without
9956 duplicates, but for_each_template_parm_r recursively calls
9957 for_each_template_parm, so we would need to reorganize a fair
9958 bit to use walk_tree_without_duplicates, so we keep our own
9959 visited list.) */
9962 else
9965 for_each_template_parm_r,
9969 /* Clean up. */
9971 {
9974 }
9977 }
9979 /* Returns true if T depends on any template parameter. */
9981 int
9983 {
10013 else
10014 {
10017 }
10022 }
10024 /* Returns true iff current_function_decl is an incompletely instantiated
10025 template. Useful instead of processing_template_decl because the latter
10026 is set to 0 during instantiate_non_dependent_expr. */
10028 bool
10030 {
10039 }
10041 /* Returns true if T depends on any template parameter with level LEVEL. */
10043 bool
10045 {
10048 }
10050 /* Returns true if the signature of DECL depends on any template parameter from
10051 its enclosing class. */
10053 bool
10055 {
10065 template_parm_outer_level,
10075 }
10077 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10078 ill-formed translation unit, i.e. a variable or function that isn't
10079 usable in a constant expression. */
10083 {
10088 }
10090 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10091 neglectable and instantiated from within an erroneous instantiation. */
10093 static bool
10095 {
10106 }
10114 /* We're starting to instantiate D; record the template instantiation context
10115 at LOC for diagnostics and to restore it later. */
10117 static bool
10119 {
10123 {
10124 /* Tell error.c not to try to instantiate any templates. */
10127 "template instantiation depth exceeds maximum of %d"
10129 max_tinst_depth);
10131 }
10133 /* If the current instantiation caused problems, don't let it instantiate
10134 anything else. Do allow deduction substitution and decls usable in
10135 constant expressions. */
10139 /* When not -quiet, dump template instantiations other than functions, since
10140 announce_function will take care of those. */
10161 }
10163 /* We're starting substitution of TMPL<ARGS>; record the template
10164 substitution context for diagnostics and to restore it later. */
10166 static bool
10168 {
10170 }
10172 /* We're starting to instantiate D; record INPUT_LOCATION and the
10173 template instantiation context for diagnostics and to restore it
10174 later. */
10176 bool
10178 {
10180 }
10182 /* Likewise, but record LOC as the program location. */
10184 bool
10186 {
10189 }
10191 /* We're done instantiating this template; return to the instantiation
10192 context. */
10194 void
10196 {
10197 /* Restore the filename and line number stashed away when we started
10198 this instantiation. */
10202 }
10204 /* We're instantiating a deferred template; restore the template
10205 instantiation context in which the instantiation was requested, which
10206 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
10208 static tree
10210 {
10222 }
10224 /* Returns the TINST_LEVEL which gives the original instantiation
10225 context. */
10229 {
10235 }
10237 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
10238 vector of template arguments, as for tsubst.
10240 Returns an appropriate tsubst'd friend declaration. */
10242 static tree
10244 {
10245 tree new_friend;
10250 /* This was a friend declared with an explicit template
10251 argument list, e.g.:
10253 friend void f<>(T);
10255 to indicate that f was a template instantiation, not a new
10256 function declaration. Now, we have to figure out what
10257 instantiation of what template. */
10258 {
10260 tree new_args;
10261 tree tmpl;
10264 /* Friend functions are looked up in the containing namespace scope.
10265 We must enter that scope, to avoid finding member functions of the
10266 current class with same name. */
10281 tsk_none);
10283 }
10287 /* The NEW_FRIEND will look like an instantiation, to the
10288 compiler, but is not an instantiation from the point of view of
10289 the language. For example, we might have had:
10291 template <class T> struct S {
10292 template <class U> friend void f(T, U);
10293 };
10295 Then, in S<int>, template <class U> void f(int, U) is not an
10296 instantiation of anything. */
10302 {
10306 }
10308 /* The mangled name for the NEW_FRIEND is incorrect. The function
10309 is not a template instantiation and should not be mangled like
10310 one. Therefore, we forget the mangling here; we'll recompute it
10311 later if we need it. */
10313 {
10316 }
10319 {
10320 tree old_decl;
10321 tree new_friend_template_info;
10322 tree new_friend_result_template_info;
10323 tree ns;
10326 /* We must save some information from NEW_FRIEND before calling
10327 duplicate decls since that function will free NEW_FRIEND if
10328 possible. */
10330 new_friend_is_defn =
10335 {
10336 /* This declaration is a `primary' template. */
10339 new_friend_result_template_info
10341 }
10342 else
10345 /* Inside pushdecl_namespace_level, we will push into the
10346 current namespace. However, the friend function should go
10347 into the namespace of the template. */
10357 {
10358 /* This new friend declaration matched an existing
10359 declaration. For example, given:
10361 template <class T> void f(T);
10362 template <class U> class C {
10363 template <class T> friend void f(T) {}
10364 };
10366 the friend declaration actually provides the definition
10367 of `f', once C has been instantiated for some type. So,
10368 old_decl will be the out-of-class template declaration,
10369 while new_friend is the in-class definition.
10371 But, if `f' was called before this point, the
10372 instantiation of `f' will have DECL_TI_ARGS corresponding
10373 to `T' but not to `U', references to which might appear
10374 in the definition of `f'. Previously, the most general
10375 template for an instantiation of `f' was the out-of-class
10376 version; now it is the in-class version. Therefore, we
10377 run through all specialization of `f', adding to their
10378 DECL_TI_ARGS appropriately. In particular, they need a
10379 new set of outer arguments, corresponding to the
10380 arguments for this class instantiation.
10382 The same situation can arise with something like this:
10384 friend void f(int);
10385 template <class T> class C {
10386 friend void f(T) {}
10387 };
10389 when `C<int>' is instantiated. Now, `f(int)' is defined
10390 in the class. */
10393 /* On the other hand, if the in-class declaration does
10394 *not* provide a definition, then we don't want to alter
10395 existing definitions. We can just leave everything
10396 alone. */
10397 ;
10398 else
10399 {
10403 /* Overwrite whatever template info was there before, if
10404 any, with the new template information pertaining to
10405 the declaration. */
10409 {
10410 /* We should have called reregister_specialization in
10411 duplicate_decls. */
10416 /* Instantiate it if the global has already been used. */
10420 }
10421 else
10422 {
10423 tree t;
10425 /* Indicate that the old function template is a partial
10426 instantiation. */
10434 /* Reassign any specializations already in the hash table
10435 to the new more general template, and add the
10436 additional template args. */
10440 {
10442 spec_entry elt;
10454 register_specialization
10457 }
10459 }
10460 }
10462 /* The information from NEW_FRIEND has been merged into OLD_DECL
10463 by duplicate_decls. */
10465 }
10466 }
10467 else
10468 {
10472 /* In the code
10473 template <class T> class C {
10474 template <class U> friend void C1<U>::f (); // case 1
10475 friend void C2<T>::f (); // case 2
10476 };
10477 we only need to make sure CONTEXT is a complete type for
10478 case 2. To distinguish between the two cases, we note that
10479 CONTEXT of case 1 remains dependent type after tsubst while
10480 this isn't true for case 2. */
10490 {
10492 /* do_friend adds the TEMPLATE_DECL for any member friend
10493 template even if it isn't a member template, i.e.
10494 template <class T> friend A<T>::f();
10495 Look through it in that case. */
10499 /* Check to see that the declaration is really present, and,
10500 possibly obtain an improved declaration. */
10505 }
10506 }
10509 }
10511 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10512 template arguments, as for tsubst.
10514 Returns an appropriate tsubst'd friend type or error_mark_node on
10515 failure. */
10517 static tree
10519 {
10520 tree tmpl;
10523 {
10526 }
10531 else
10539 {
10540 /* The friend template has already been declared. Just
10541 check to see that the declarations match, and install any new
10542 default parameters. We must tsubst the default parameters,
10543 of course. We only need the innermost template parameters
10544 because that is all that redeclare_class_template will look
10545 at. */
10548 {
10556 }
10557 }
10558 else
10559 {
10560 /* The friend template has not already been declared. In this
10561 case, the instantiation of the template class will cause the
10562 injection of this template into the namespace scope. */
10566 {
10567 /* The new TMPL is not an instantiation of anything, so we
10568 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10569 for the new type because that is supposed to be the
10570 corresponding template decl, i.e., TMPL. */
10577 /* It is hidden. */
10582 /* Inject this template into the enclosing namspace scope. */
10584 }
10585 }
10589 else
10593 }
10595 /* Returns zero if TYPE cannot be completed later due to circularity.
10596 Otherwise returns one. */
10598 static int
10600 {
10610 else
10612 }
10617 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10618 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10620 static tree
10623 {
10632 {
10639 clauses
10643 else
10645 }
10646 /* If the first attribute argument is an identifier, don't
10647 pass it through tsubst. Attributes like mode, format,
10648 cleanup and several target specific attributes expect it
10649 unmodified. */
10651 {
10652 tree chain
10657 }
10659 {
10660 /* An attribute pack expansion. */
10669 {
10673 }
10675 }
10676 else
10683 }
10685 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10686 unchanged or a new TREE_LIST chain. */
10688 static tree
10691 {
10696 {
10700 }
10704 {
10707 {
10710 {
10716 }
10717 }
10719 }
10722 }
10724 /* Apply any attributes which had to be deferred until instantiation
10725 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10726 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10728 static void
10731 {
10733 tree t;
10740 {
10744 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10745 to our attributes parameter. */
10747 }
10748 else
10749 {
10751 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10752 lookup_template_class_1, and should be preserved. */
10756 }
10760 {
10764 }
10768 {
10773 {
10776 {
10782 }
10783 else
10785 }
10788 }
10789 }
10791 /* Perform (or defer) access check for typedefs that were referenced
10792 from within the template TMPL code.
10793 This is a subroutine of instantiate_decl and instantiate_class_template.
10794 TMPL is the template to consider and TARGS is the list of arguments of
10795 that template. */
10797 static void
10799 {
10800 location_t saved_location;
10811 {
10823 /* Make access check error messages point to the location
10824 of the use of the typedef. */
10828 tf_warning_or_error);
10829 }
10831 }
10833 static tree
10835 {
10837 tree typedecl;
10838 tree pbinfo;
10839 tree base_list;
10841 tree fn_context;
10850 /* Figure out which template is being instantiated. */
10854 /* Mark the type as in the process of being defined. */
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. */
10896 /* We may be in the middle of deferred access check. Disable
10897 it now. */
10904 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10909 else
10910 {
10913 }
10914 /* Use #pragma pack from the template context. */
10920 /* Set the input location to the most specialized template definition.
10921 This is needed if tsubsting causes an error. */
10933 {
10936 /* Adjust visibility for template arguments. */
10938 }
10944 /* We should never instantiate a nested class before its enclosing
10945 class; we need to look up the nested class by name before we can
10946 instantiate it, and that lookup should instantiate the enclosing
10947 class. */
10953 {
10954 tree pbase_binfo;
10955 tree pushed_scope;
10958 /* We must enter the scope containing the type, as that is where
10959 the accessibility of types named in dependent bases are
10960 looked up from. */
10963 /* Substitute into each of the bases to determine the actual
10964 basetypes. */
10966 {
10967 tree base;
10973 {
10974 expanded_bases =
10981 }
10984 {
10986 /* Extract the already-expanded base class. */
10988 else
10989 /* Substitute to figure out the base class. */
10991 NULL_TREE);
10999 }
11000 }
11002 /* The list is now in reverse order; correct that. */
11007 }
11008 /* Now call xref_basetypes to set up all the base-class
11009 information. */
11017 /* Now that our base classes are set up, enter the scope of the
11018 class, so that name lookups into base classes, etc. will work
11019 correctly. This is precisely analogous to what we do in
11020 begin_class_definition when defining an ordinary non-template
11021 class, except we also need to push the enclosing classes. */
11024 /* Now members are processed in the order of declaration. */
11027 {
11031 {
11033 {
11035 /* A closure type for a lambda in an NSDMI or default argument.
11036 Ignore it; it will be regenerated when needed. */
11039 /* Build new CLASSTYPE_NESTED_UTDS. */
11041 tree newtag;
11047 /* If the member is a class template, then -- even after
11048 substitution -- there may be dependent types in the
11049 template argument list for the class. We increment
11050 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11051 that function will assume that no types are dependent
11052 when outside of a template. */
11062 {
11066 /* Unfortunately, lookup_template_class sets
11067 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11068 instantiation (i.e., for the type of a member
11069 template class nested within a template class.)
11070 This behavior is required for
11071 maybe_process_partial_specialization to work
11072 correctly, but is not accurate in this case;
11073 the TAG is not an instantiation of anything.
11074 (The corresponding TEMPLATE_DECL is an
11075 instantiation, but the TYPE is not.) */
11078 /* Now, we call pushtag to put this NEWTAG into the scope of
11079 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
11080 pushtag calling push_template_decl. We don't have to do
11081 this for enums because it will already have been done in
11082 tsubst_enum. */
11086 }
11087 }
11089 {
11090 tree r;
11099 /* Instantiate members marked with attribute used. */
11105 }
11108 /* A closure type for a lambda in an NSDMI or default argument.
11110 else
11111 {
11112 /* Build new TYPE_FIELDS. */
11114 {
11115 tree condition;
11118 condition =
11128 }
11130 {
11131 tree r;
11135 /* The file and line for this declaration, to
11136 assist in error message reporting. Since we
11137 called push_tinst_level above, we don't need to
11138 restore these. */
11148 {
11149 /* A capture pack became multiple fields. */
11152 }
11155 {
11159 {
11160 /* In [temp.inst]:
11162 [t]he initialization (and any associated
11163 side-effects) of a static data member does
11164 not occur unless the static data member is
11165 itself used in a way that requires the
11166 definition of the static data member to
11167 exist.
11169 Therefore, we do not substitute into the
11170 initialized for the static data member here. */
11171 finish_static_data_member_decl
11177 /* Instantiate members marked with attribute used. */
11180 }
11182 {
11183 /* Determine whether R has a valid type and can be
11184 completed later. If R is invalid, then its type
11185 is replaced by error_mark_node. */
11191 {
11192 /* If R's type couldn't be completed and
11193 it isn't a flexible array member (whose
11194 type is incomplete by definition) give
11195 an error. */
11198 }
11203 {
11206 }
11207 }
11209 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
11210 such a thing will already have been added to the field
11211 list by tsubst_enum in finish_member_declaration in the
11212 CLASSTYPE_NESTED_UTDS case above. */
11216 {
11219 }
11220 }
11221 }
11222 }
11223 }
11224 else
11225 {
11228 {
11229 /* Build new CLASSTYPE_FRIEND_CLASSES. */
11235 {
11236 /* template <class T> friend class C; */
11239 }
11241 {
11242 /* template <class T> friend class C::D; */
11248 }
11251 {
11252 /* This could be either
11254 friend class T::C;
11256 when dependent_type_p is false or
11258 template <class U> friend class T::C;
11260 otherwise. */
11261 /* Bump processing_template_decl in case this is something like
11262 template <class T> friend struct A<T>::B. */
11269 }
11273 {
11274 /* friend class C;
11276 where C hasn't been declared yet. Let's lookup name
11277 from namespace scope directly, bypassing any name that
11278 come from dependent base class. */
11281 /* The call to xref_tag_from_type does injection for friend
11282 classes. */
11284 friend_type =
11288 }
11290 /* friend class C<T>; */
11293 /* Otherwise it's
11295 friend class C;
11297 where C is already declared or
11299 friend class C<int>;
11301 We don't have to do anything in these cases. */
11304 /* Trick make_friend_class into realizing that the friend
11305 we're adding is a template, not an ordinary class. It's
11306 important that we use make_friend_class since it will
11307 perform some error-checking and output cross-reference
11308 information. */
11316 }
11317 else
11318 {
11319 /* Build new DECL_FRIENDLIST. */
11320 tree r;
11322 /* The file and line for this declaration, to
11323 assist in error message reporting. Since we
11324 called push_tinst_level above, we don't need to
11325 restore these. */
11329 {
11332 }
11337 {
11340 }
11341 }
11342 }
11343 }
11346 {
11347 /* Restore these before substituting into the lambda capture
11348 initializers. */
11351 }
11353 /* Set the file and line number information to whatever is given for
11354 the class itself. This puts error messages involving generated
11355 implicit functions at a predictable point, and the same point
11356 that would be used for non-template classes. */
11363 /* We don't instantiate default arguments for member functions. 14.7.1:
11365 The implicit instantiation of a class template specialization causes
11366 the implicit instantiation of the declarations, but not of the
11367 definitions or default arguments, of the class member functions,
11368 member classes, static data members and member templates.... */
11370 /* Some typedefs referenced from within the template code need to be access
11371 checked at template instantiation time, i.e now. These types were
11372 added to the template at parsing time. Let's get those and perform
11373 the access checks then. */
11383 /* The vtable for a template class can be emitted in any translation
11384 unit in which the class is instantiated. When there is no key
11385 method, however, finish_struct_1 will already have added TYPE to
11386 the keyed_classes. */
11391 }
11393 /* Wrapper for instantiate_class_template_1. */
11395 tree
11397 {
11398 tree ret;
11403 }
11405 static tree
11407 {
11408 tree r;
11414 else
11415 {
11422 }
11424 }
11426 /* Given a function parameter pack TMPL_PARM and some function parameters
11427 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11428 and set *SPEC_P to point at the next point in the list. */
11430 tree
11432 {
11433 /* Collect all of the extra "packed" parameters into an
11434 argument pack. */
11435 tree parmvec;
11445 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11449 {
11454 }
11456 /* Build the argument packs. */
11461 }
11463 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11464 NONTYPE_ARGUMENT_PACK. */
11466 static tree
11468 {
11470 }
11472 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11473 pack expansion with no extra args, 2 if it has extra args, or 0
11474 if it is not a pack expansion. */
11476 static int
11478 {
11484 /* A decl pack is itself an expansion. */
11491 }
11494 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11496 static tree
11498 {
11505 }
11507 /* This is a subroutine of tsubst_pack_expansion.
11509 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11510 mechanism to store the (non complete list of) arguments of the
11511 substitution and return a non substituted pack expansion, in order
11512 to wait for when we have enough arguments to really perform the
11513 substitution. */
11515 static bool
11519 {
11520 /* If one pack has an expansion and another pack has a normal
11521 argument or if one pack has an empty argument and an another
11522 one hasn't then tsubst_pack_expansion cannot perform the
11523 substitution and need to fall back on the
11524 PACK_EXPANSION_EXTRA mechanism. */
11532 {
11535 parm_pack;
11537 {
11542 /* We can't substitute a pack expansion with extra args into
11543 our pattern. */
11547 else
11549 }
11553 }
11555 }
11557 /* [temp.variadic]/6 says that:
11559 The instantiation of a pack expansion [...]
11560 produces a list E1,E2, ..., En, where N is the number of elements
11561 in the pack expansion parameters.
11563 This subroutine of tsubst_pack_expansion produces one of these Ei.
11565 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11566 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11567 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11568 INDEX is the index 'i' of the element Ei to produce. ARGS,
11569 COMPLAIN, and IN_DECL are the same parameters as for the
11570 tsubst_pack_expansion function.
11572 The function returns the resulting Ei upon successful completion,
11573 or error_mark_node.
11575 Note that this function possibly modifies the ARGS parameter, so
11576 it's the responsibility of the caller to restore it. */
11578 static tree
11580 tree parm_packs,
11582 tree args /* This parm gets
11584 tsubst_flags_t complain,
11585 tree in_decl)
11586 {
11587 tree t;
11590 /* For each parameter pack, change the substitution of the parameter
11591 pack to the ith argument in its argument pack, then expand the
11592 pattern. */
11594 {
11599 ith_elem_is_expansion |=
11602 /* Select the Ith argument from the pack. */
11606 {
11608 {
11613 }
11614 else
11616 }
11617 else
11618 {
11623 {
11625 /* Update the corresponding argument. */
11627 }
11628 else
11629 /* Re-use the ARGUMENT_PACK_SELECT. */
11631 }
11633 }
11635 /* Substitute into the PATTERN with the (possibly altered)
11636 arguments. */
11638 /* Expanding a fixed parameter pack from
11639 coerce_template_parameter_pack. */
11644 {
11647 else
11650 }
11654 else
11657 /* If the Ith argument pack element is a pack expansion, then
11658 the Ith element resulting from the substituting is going to
11659 be a pack expansion as well. */
11664 }
11666 /* When the unexpanded parameter pack in a fold expression expands to an empty
11667 sequence, the value of the expression is as follows; the program is
11668 ill-formed if the operator is not listed in this table.
11670 && true
11671 || false
11672 , void() */
11674 tree
11676 {
11680 {
11689 }
11695 }
11697 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11698 form an expression that combines the two terms using the
11699 operator of T. */
11701 static tree
11703 {
11707 // Handle compound assignment operators.
11712 {
11722 complain);
11723 }
11724 }
11726 /* Substitute ARGS into the pack of a fold expression T. */
11730 {
11732 }
11734 /* Substitute ARGS into the pack of a fold expression T. */
11738 {
11740 }
11742 /* Expand a PACK of arguments into a grouped as left fold.
11743 Given a pack containing elements A0, A1, ..., An and an
11744 operator @, this builds the expression:
11746 ((A0 @ A1) @ A2) ... @ An
11748 Note that PACK must not be empty.
11750 The operator is defined by the original fold expression T. */
11752 static tree
11754 {
11757 {
11760 }
11762 }
11764 /* Substitute into a unary left fold expression. */
11766 static tree
11768 tree in_decl)
11769 {
11774 {
11778 }
11781 else
11783 }
11785 /* Substitute into a binary left fold expression.
11787 Do ths by building a single (non-empty) vector of argumnts and
11788 building the expression from those elements. */
11790 static tree
11792 tree in_decl)
11793 {
11802 {
11807 }
11815 }
11817 /* Expand a PACK of arguments into a grouped as right fold.
11818 Given a pack containing elementns A0, A1, ..., and an
11819 operator @, this builds the expression:
11821 A0@ ... (An-2 @ (An-1 @ An))
11823 Note that PACK must not be empty.
11825 The operator is defined by the original fold expression T. */
11827 tree
11829 {
11830 // Build the expression.
11834 {
11837 }
11839 }
11841 /* Substitute into a unary right fold expression. */
11843 static tree
11845 tree in_decl)
11846 {
11851 {
11855 }
11858 else
11860 }
11862 /* Substitute into a binary right fold expression.
11864 Do ths by building a single (non-empty) vector of arguments and
11865 building the expression from those elements. */
11867 static tree
11869 tree in_decl)
11870 {
11879 {
11884 }
11893 }
11895 /* Walk through the pattern of a pack expansion, adding everything in
11896 local_specializations to a list. */
11898 struct el_data
11899 {
11901 tree extra;
11902 tsubst_flags_t complain;
11906 };
11907 static tree
11909 {
11915 /* Remember local typedefs (85214). */
11921 {
11923 /* Don't mess with variables declared within the pattern. */
11926 {
11927 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11930 {
11936 }
11938 {
11939 /* Handle lambda capture here, since we aren't doing any
11940 substitution now, and so tsubst_copy won't call
11941 process_outer_var_ref. */
11945 {
11951 {
11952 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11953 proxies. */
11955 {
11960 }
11962 }
11963 }
11964 }
11965 }
11969 }
11971 }
11972 static tree
11974 {
11978 }
11980 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
11981 for use in PACK_EXPANSION_EXTRA_ARGS. */
11983 tree
11985 {
11991 }
11993 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
11994 normal template args to ARGS. */
11996 tree
11998 {
12000 {
12002 {
12003 /* The partial instantiation involved local declarations collected in
12004 extract_local_specs; map from the general template to our local
12005 context. */
12011 /* else inst is already a full instantiation of the pack. */
12013 }
12016 }
12018 }
12020 /* Substitute ARGS into T, which is an pack expansion
12021 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12022 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12023 (if only a partial substitution could be performed) or
12024 ERROR_MARK_NODE if there was an error. */
12025 tree
12027 tree in_decl)
12028 {
12029 tree pattern;
12034 tree result;
12042 /* Add in any args remembered from an earlier partial instantiation. */
12047 /* Determine the argument packs that will instantiate the parameter
12048 packs used in the expansion expression. While we're at it,
12049 compute the number of arguments to be expanded and make sure it
12050 is consistent. */
12053 {
12060 {
12066 complain);
12067 else
12071 }
12073 {
12074 /* ??? Support use in other patterns. */
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 {
14026 }
14027 else
14028 {
14030 /* Don't pick up extra function qualifiers from the basetype. */
14033 {
14034 /* [temp.deduct]
14036 Type deduction may fail for any of the following
14037 reasons:
14039 -- Attempting to create "pointer to member of T" when T
14040 is not a class type. */
14043 r);
14045 }
14050 }
14057 }
14059 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
14060 ARGS into that specification, and return the substituted
14061 specification. If there is no specification, return NULL_TREE. */
14063 static tree
14065 tree args,
14066 tsubst_flags_t complain,
14067 tree in_decl,
14069 {
14070 tree specs;
14071 tree new_specs;
14076 {
14077 /* A noexcept-specifier. */
14082 {
14083 /* Defer instantiation of noexcept-specifiers to avoid
14084 excessive instantiations (c++/49107). */
14087 {
14088 /* We already partially instantiated this member template,
14089 so combine the new args with the old. */
14094 }
14095 else
14096 {
14099 }
14100 }
14101 else
14102 new_specs = tsubst_copy_and_build
14106 }
14108 {
14111 else
14113 {
14114 tree spec;
14119 {
14120 /* Expand the pack expansion type. */
14123 in_decl);
14129 else
14130 {
14131 /* We're substituting into a member template, so
14132 we got a TYPE_PACK_EXPANSION back. Add that
14133 expansion and move on. */
14137 expanded_specs,
14138 complain);
14141 }
14142 }
14145 {
14148 else
14153 complain);
14154 }
14157 }
14158 }
14160 }
14162 /* Take the tree structure T and replace template parameters used
14163 therein with the argument vector ARGS. IN_DECL is an associated
14164 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
14165 Issue error and warning messages under control of COMPLAIN. Note
14166 that we must be relatively non-tolerant of extensions here, in
14167 order to preserve conformance; if we allow substitutions that
14168 should not be allowed, we may allow argument deductions that should
14169 not succeed, and therefore report ambiguous overload situations
14170 where there are none. In theory, we could allow the substitution,
14171 but indicate that it should have failed, and allow our caller to
14172 make sure that the right thing happens, but we don't try to do this
14173 yet.
14175 This function is used for dealing with types, decls and the like;
14176 for expressions, use tsubst_expr or tsubst_copy. */
14178 tree
14180 {
14203 else
14208 /* Reuse typedefs. We need to do this to handle dependent attributes,
14209 such as attribute aligned. */
14212 {
14216 {
14217 /* DECL represents an alias template and we want to
14218 instantiate it. */
14222 }
14226 {
14230 }
14235 else
14236 /* The typedef is from a non-template context. */
14240 {
14242 r = cp_build_qualified_type_real
14246 }
14247 else
14248 {
14249 /* We don't have an instantiation yet, so drop the typedef. */
14254 }
14255 }
14272 {
14298 {
14304 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
14305 needed. */
14311 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
14312 with TREE_SIDE_EFFECTS that indicates this is not an integral
14313 constant expression. */
14316 {
14319 }
14322 }
14328 {
14334 /* Early in template argument deduction substitution, we don't
14335 want to reduce the level of 'auto', or it will be confused
14336 with a normal template parm in subsequent deduction. */
14348 {
14351 /* See through ARGUMENT_PACK_SELECT arguments. */
14354 }
14359 {
14361 /* If ARG is an argument pack, we don't actually want to
14362 perform a substitution here, because substitutions
14363 for argument packs are only done
14364 element-by-element. We can get to this point when
14365 substituting the type of a non-type template
14366 parameter pack, when that type actually contains
14367 template parameter packs from an outer template, e.g.,
14369 template<typename... Types> struct A {
14370 template<Types... Values> struct B { };
14371 }; */
14375 {
14381 return cp_build_qualified_type_real
14383 }
14385 {
14386 /* We are processing a type constructed from a
14387 template template parameter. */
14398 /* Consider this code:
14400 template <template <class> class Template>
14401 struct Internal {
14402 template <class Arg> using Bind = Template<Arg>;
14403 };
14405 template <template <class> class Template, class Arg>
14406 using Instantiate = Template<Arg>; //#0
14408 template <template <class> class Template,
14409 class Argument>
14410 using Bind =
14411 Instantiate<Internal<Template>::template Bind,
14412 Argument>; //#1
14414 When #1 is parsed, the
14415 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14416 parameter `Template' in #0 matches the
14417 UNBOUND_CLASS_TEMPLATE representing the argument
14418 `Internal<Template>::template Bind'; We then want
14419 to assemble the type `Bind<Argument>' that can't
14420 be fully created right now, because
14421 `Internal<Template>' not being complete, the Bind
14422 template cannot be looked up in that context. So
14423 we need to "store" `Bind<Argument>' for later
14424 when the context of Bind becomes complete. Let's
14425 store that in a TYPENAME_TYPE. */
14429 argvec),
14430 typename_type,
14431 complain);
14433 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14434 are resolving nested-types in the signature of a
14435 member function templates. Otherwise ARG is a
14436 TEMPLATE_DECL and is the real template to be
14437 instantiated. */
14445 complain);
14446 return cp_build_qualified_type_real
14448 }
14451 else
14452 /* TEMPLATE_PARM_INDEX. */
14454 }
14457 /* This can happen during the attempted tsubst'ing in
14458 unify. This means that we don't yet have any information
14459 about the template parameter in question. */
14462 /* If we get here, we must have been looking at a parm for a
14463 more deeply nested template. Make a new version of this
14464 template parameter, but with a lower level. */
14466 {
14471 {
14473 r = cp_build_qualified_type_real
14477 }
14484 /* Break infinite recursion when substituting the constraints
14486 else
14487 {
14498 {
14499 /* Propagate constraints on placeholders. */
14504 {
14507 }
14508 }
14511 /* We have reduced the level of the template
14512 template parameter, but not the levels of its
14513 template parameters, so canonical_type_parameter
14514 will not be able to find the canonical template
14515 template parameter for this level. Thus, we
14516 require structural equality checking to compare
14517 TEMPLATE_TEMPLATE_PARMs. */
14521 else
14525 {
14527 /* We might need to substitute into the types of non-type
14528 template parameters. */
14540 }
14541 }
14545 /* OK, now substitute the type of the non-type parameter. We
14546 couldn't do it earlier because it might be an auto parameter,
14547 and we wouldn't need to if we had an argument. */
14556 }
14559 }
14562 {
14570 {
14574 }
14577 {
14581 }
14584 {
14588 }
14594 }
14597 /* We should never be tsubsting a binfo. */
14601 /* A vector of template arguments. */
14607 {
14611 /* [temp.deduct]
14613 Type deduction may fail for any of the following
14614 reasons:
14616 -- Attempting to create a pointer to reference type.
14617 -- Attempting to create a reference to a reference type or
14618 a reference to void.
14620 Core issue 106 says that creating a reference to a reference
14621 during instantiation is no longer a cause for failure. We
14622 only enforce this check in strict C++98 mode. */
14626 {
14629 /* We keep track of the last time we issued this error
14630 message to avoid spewing a ton of messages during a
14631 single bad template instantiation. */
14634 {
14639 else
14642 }
14645 }
14649 {
14651 {
14654 type);
14655 else
14657 type);
14658 }
14660 }
14662 {
14666 }
14668 /* In C++0x, during template argument substitution, when there is an
14669 attempt to create a reference to a reference type, reference
14670 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14672 "If a template-argument for a template-parameter T names a type
14673 that is a reference to a type A, an attempt to create the type
14674 'lvalue reference to cv T' creates the type 'lvalue reference to
14675 A,' while an attempt to create the type type rvalue reference to
14676 cv T' creates the type T"
14677 */
14678 r = cp_build_reference_type
14681 else
14686 /* Will this ever be needed for TYPE_..._TO values? */
14690 }
14692 {
14695 {
14696 /* [temp.deduct]
14698 Type deduction may fail for any of the following
14699 reasons:
14701 -- Attempting to create "pointer to member of T" when T
14702 is not a class type. */
14706 }
14708 {
14712 }
14714 {
14718 }
14721 {
14722 /* The type of the implicit object parameter gets its
14723 cv-qualifiers from the FUNCTION_TYPE. */
14724 tree memptr;
14725 tree method_type
14730 complain);
14731 }
14732 else
14735 complain);
14736 }
14739 {
14740 tree fntype;
14741 tree specs;
14746 /* Substitute the exception specification. */
14754 }
14756 {
14761 /* As an optimization, we avoid regenerating the array type if
14762 it will obviously be the same as T. */
14766 /* These checks should match the ones in create_array_type_for_decl.
14768 [temp.deduct]
14770 The deduction may fail for any of the following reasons:
14772 -- Attempting to create an array with an element type that
14773 is void, a function type, or a reference type, or [DR337]
14774 an abstract class type. */
14780 {
14784 }
14792 {
14795 }
14798 }
14801 {
14813 {
14817 }
14819 {
14820 /* Normally, make_typename_type does not require that the CTX
14821 have complete type in order to allow things like:
14823 template <class T> struct S { typename S<T>::X Y; };
14825 But, such constructs have already been resolved by this
14826 point, so here CTX really should have complete type, unless
14827 it's a partial instantiation. */
14830 {
14834 }
14835 }
14842 {
14845 }
14848 {
14850 {
14854 else
14856 }
14858 {
14862 else
14864 }
14865 }
14867 return cp_build_qualified_type_real
14869 }
14872 {
14884 }
14887 {
14888 tree type;
14904 complain);
14905 }
14908 {
14909 tree type;
14920 {
14922 {
14926 }
14929 }
14940 else
14941 {
14945 /* In a template ~id could be either a complement expression
14946 or an unqualified-id naming a destructor; if instantiating
14947 it produces an expression, it's not an id-expression or
14948 member access. */
14951 }
14956 }
14959 {
14963 }
14967 {
14968 tree r;
14972 else
14980 }
14995 /* We should use one of the expression tsubsts for these codes. */
15001 }
15002 }
15004 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
15005 expression on the left-hand side of the "." or "->" operator. We
15006 only do the lookup if we had a dependent BASELINK. Otherwise we
15007 adjust it onto the instantiated heirarchy. */
15009 static tree
15012 {
15024 {
15031 }
15038 {
15044 /* Treat as-if non-dependent below. */
15049 {
15055 }
15059 }
15060 else
15061 /* We're going to overwrite pieces below, make a duplicate. */
15064 /* If lookup found a single function, mark it as used at this point.
15065 (If lookup found multiple functions the one selected later by
15066 overload resolution will be marked as used at that point.) */
15068 {
15074 /* We might have instantiated an auto function. */
15076 }
15079 {
15080 /* Add back the template arguments, if present. */
15085 /* Update the conversion operator type. */
15087 }
15093 {
15095 qualifying_scope,
15096 object_type);
15098 /* We need to call adjust_result_of_qualified_name_lookup in case the
15099 destructor names a base class, but we unset BASELINK_QUALIFIED_P
15100 so that we still get virtual function binding. */
15102 }
15105 }
15107 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
15108 true if the qualified-id will be a postfix-expression in-and-of
15109 itself; false if more of the postfix-expression follows the
15110 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
15111 of "&". */
15113 static tree
15117 {
15118 tree expr;
15119 tree scope;
15120 tree name;
15122 tree template_args;
15127 /* Figure out what name to look up. */
15130 {
15140 }
15141 else
15142 {
15145 }
15147 /* Substitute into the qualifying scope. When there are no ARGS, we
15148 are just trying to simplify a non-dependent expression. In that
15149 case the qualifying scope may be dependent, and, in any case,
15150 substituting will not help. */
15153 {
15156 }
15157 else
15161 {
15168 }
15171 {
15173 {
15174 /* A BIT_NOT_EXPR is used to represent a destructor. */
15176 {
15180 }
15181 else
15184 }
15185 else
15189 {
15191 {
15195 }
15197 }
15198 }
15201 {
15203 scope);
15204 /* Remember that there was a reference to this entity. */
15207 }
15210 {
15216 }
15219 {
15220 /* We may be repeating a check already done during parsing, but
15221 if it was well-formed and passed then, it will pass again
15222 now, and if it didn't, we wouldn't have got here. The case
15223 we want to catch is when we couldn't tell then, and can now,
15224 namely when templ prior to substitution was an
15225 identifier. */
15231 complain);
15232 else
15234 }
15240 {
15241 expr = (adjust_result_of_qualified_name_lookup
15243 expr = (finish_qualified_id_expr
15247 }
15249 /* Expressions do not generally have reference type. */
15251 /* However, if we're about to form a pointer-to-member, we just
15252 want the referenced member referenced. */
15260 }
15262 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
15263 initializer, DECL is the substituted VAR_DECL. Other arguments are as
15264 for tsubst. */
15266 static tree
15269 {
15276 {
15277 /* If we had an initializer but it
15278 instantiated to nothing,
15279 value-initialize the object. This will
15280 only occur when the initializer was a
15281 pack expansion where the parameter packs
15282 used in that expansion were of length
15283 zero. */
15285 complain);
15290 }
15293 }
15295 /* Like tsubst, but deals with expressions. This function just replaces
15296 template parms; to finish processing the resultant expression, use
15297 tsubst_copy_and_build or tsubst_expr. */
15299 static tree
15301 {
15303 tree r;
15311 {
15316 {
15317 /* We get here for a use of 'this' in an NSDMI. */
15321 /* This can happen for a parameter name used later in a function
15322 declaration (such as in a late-specified return type). Just
15323 make a dummy decl, since it's only used for its type. */
15326 /* Give it the template pattern as its context; its true context
15327 hasn't been instantiated yet and this is good enough for
15328 mangling. */
15330 }
15339 {
15340 tree enum_type;
15341 tree v;
15345 /* There is no need to substitute into namespace-scope
15346 enumerators. */
15349 /* If ARGS is NULL, then T is known to be non-dependent. */
15353 /* Unfortunately, we cannot just call lookup_name here.
15354 Consider:
15356 template <int I> int f() {
15357 enum E { a = I };
15358 struct S { void g() { E e = a; } };
15359 };
15361 When we instantiate f<7>::S::g(), say, lookup_name is not
15362 clever enough to find f<7>::a. */
15363 enum_type
15373 /* We didn't find the name. That should never happen; if
15374 name-lookup found it during preliminary parsing, we
15375 should find it again here during instantiation. */
15377 }
15382 {
15383 tree ctx;
15388 {
15391 {
15395 }
15397 }
15398 }
15408 {
15411 {
15412 /* First try name lookup to find the instantiation. */
15415 {
15416 /* Make sure that the one we found is the one we want. */
15420 }
15424 else
15425 {
15426 /* This can happen for a variable used in a
15427 late-specified return type of a local lambda, or for a
15428 local static or constant. Building a new VAR_DECL
15429 should be OK in all those cases. */
15432 /* Avoid infinite recursion (79640). */
15435 {
15436 /* We can't call cp_finish_decl, so handle the
15437 initializer by hand. */
15452 }
15459 }
15460 /* Remember this for subsequent uses. */
15463 }
15466 }
15467 else
15477 /* An OVERLOAD will always be a non-dependent overload set; an
15478 overload set from function scope will just be represented with an
15479 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15481 /* We must have marked any lookups as persistent. */
15497 {
15498 /* Template template argument like the following example need
15499 special treatment:
15501 template <template <class> class TT> struct C {};
15502 template <class T> struct D {
15503 template <class U> struct E {};
15504 C<E> c; // #1
15505 };
15506 D<int> d; // #2
15508 We are processing the template argument `E' in #1 for
15509 the template instantiation #2. Originally, `E' is a
15510 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15511 have to substitute this with one having context `D<int>'. */
15515 {
15516 /* When rewriting a constructor into a deduction guide, a
15517 non-dependent name can become dependent, so memtmpl<args>
15518 becomes context::template memtmpl<args>. */
15522 }
15524 }
15525 else
15526 /* Ordinary template template argument. */
15531 {
15532 /* Handle location wrappers by substituting the wrapped node
15533 first, *then* reusing the resulting type. Doing the type
15534 first ensures that we handle template parameters and
15535 parameter pack expansions. */
15539 }
15549 {
15553 }
15558 {
15567 /* We only want to compute the number of arguments. */
15570 else
15577 {
15579 /* Set TREE_USED for the benefit of -Wunused. */
15583 }
15591 {
15596 else
15603 else
15606 }
15607 else
15609 }
15611 {
15619 }
15620 /* Fall through */
15636 {
15643 }
15646 {
15647 tree object;
15648 tree name;
15653 {
15657 }
15660 {
15670 }
15675 in_decl);
15676 else
15679 }
15717 {
15721 }
15724 {
15729 }
15732 {
15736 }
15739 {
15747 }
15753 {
15760 }
15763 {
15770 }
15773 {
15780 }
15783 {
15784 /* Substituted template arguments */
15793 }
15796 {
15816 }
15841 /* Fall through. */
15844 {
15847 }
15848 else
15852 /* This is handled by tsubst_copy_and_build. */
15856 {
15860 }
15863 /* We shouldn't have built any of these during initial template
15864 generation. Instead, they should be built during instantiation
15865 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15869 {
15879 }
15897 {
15898 /* Instantiate any typedefs in the type. */
15903 }
15906 /* These can sometimes show up in a partial instantiation, but never
15907 involve template parms. */
15923 /* ??? There's no point in copying it for now, but maybe some
15924 day it will contain more information, such as a pointer back
15925 to the containing function, inlined copy or so. */
15929 /* We shouldn't get here, but keep going if !flag_checking. */
15933 }
15934 }
15936 /* Helper function for tsubst_omp_clauses, used for instantiation of
15937 OMP_CLAUSE_DECL of clauses. */
15939 static tree
15941 tree in_decl)
15942 {
15946 /* Handle an OpenMP array section represented as a TREE_LIST (or
15947 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15948 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15949 TREE_LIST. We can handle it exactly the same as an array section
15950 (purpose, value, and a chain), even though the nomenclature
15951 (low_bound, length, etc) is different. */
15953 {
15954 tree low_bound
15960 in_decl);
15969 }
15972 /* Undo convert_from_reference tsubst_expr could have called. */
15978 }
15980 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15982 static tree
15985 {
15990 {
15996 {
15999 {
16005 }
16006 /* FALLTHRU */
16021 in_decl);
16053 {
16056 {
16063 }
16064 else
16066 }
16069 in_decl);
16075 in_decl);
16083 in_decl);
16085 {
16088 }
16093 else
16096 in_decl,
16120 }
16123 {
16133 /* tsubst_expr on SCOPE_REF results in returning
16134 finish_non_static_data_member result. Undo that here. */
16138 {
16143 {
16147 CASE_CONVERT:
16156 /* FALLTHRU */
16160 }
16161 }
16167 {
16170 {
16173 }
16174 }
16178 }
16179 }
16183 {
16188 {
16191 }
16192 }
16194 }
16196 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
16198 static tree
16200 tree in_decl)
16201 {
16202 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
16222 {
16225 else
16226 {
16230 }
16231 }
16236 #undef RECUR
16237 }
16239 /* Used to temporarily communicate the list of #pragma omp parallel
16240 clauses to #pragma omp for instantiation if they are combined
16241 together. */
16245 /* Substitute one OMP_FOR iterator. */
16247 static void
16252 {
16253 #define RECUR(NODE) \
16254 tsubst_expr ((NODE), args, complain, in_decl, \
16255 integral_constant_expression_p)
16262 {
16265 }
16271 {
16272 /* We need to jump through some hoops to handle declarations in the
16273 init-statement, since we might need to handle auto deduction,
16274 but we need to keep control of initialization. */
16278 }
16279 else
16280 {
16282 {
16285 {
16289 {
16293 CASE_CONVERT:
16301 {
16304 }
16305 /* FALLTHRU */
16309 }
16310 }
16311 }
16312 else
16314 }
16325 {
16327 {
16328 /* Declare the variable, but don't let that initialize it. */
16333 }
16338 {
16343 }
16344 else
16351 }
16354 {
16355 /* Declare and initialize the variable. */
16358 }
16360 {
16364 {
16366 {
16372 {
16375 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
16380 }
16383 {
16385 decl);
16387 }
16390 {
16392 decl);
16394 }
16395 else
16397 }
16400 }
16402 {
16407 {
16410 }
16411 }
16412 }
16415 {
16419 }
16420 else
16424 {
16435 {
16443 }
16444 else
16450 {
16456 }
16460 {
16468 }
16469 else
16475 }
16481 #undef RECUR
16482 }
16484 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16485 of OMP_TARGET's body. */
16487 static tree
16489 {
16492 {
16501 }
16503 }
16505 /* Helper function for tsubst_expr. For decomposition declaration
16506 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16507 also the corresponding decls representing the identifiers
16508 of the decomposition declaration. Return DECL if successful
16509 or error_mark_node otherwise, set *FIRST to the first decl
16510 in the list chained through DECL_CHAIN and *CNT to the number
16511 of such decls. */
16513 static tree
16517 {
16522 decl2
16527 {
16529 {
16532 }
16544 else
16545 {
16549 }
16556 {
16559 }
16560 else
16562 }
16565 }
16567 /* Like tsubst_copy for expressions, etc. but also does semantic
16568 processing. */
16570 tree
16573 {
16574 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16575 #define RECUR(NODE) \
16576 tsubst_expr ((NODE), args, complain, in_decl, \
16577 integral_constant_expression_p)
16580 tree r;
16581 location_t loc;
16593 {
16595 {
16596 tree_stmt_iterator i;
16600 }
16615 else
16625 {
16627 tree init;
16633 {
16643 else
16645 }
16648 {
16649 /* We're in tsubst_lambda_expr, we've already inserted a new
16650 capture proxy, so look it up and register it. */
16651 tree inst;
16653 {
16654 inst = (retrieve_local_specialization
16657 }
16658 else
16659 {
16663 }
16666 }
16669 /* Don't copy the old closure; we'll create a new one in
16670 tsubst_lambda_expr. */
16672 else
16673 {
16677 {
16678 /* By marking the declaration as instantiated, we avoid
16679 trying to instantiate it. Since instantiate_decl can't
16680 handle local variables, and since we've already done
16681 all that needs to be done, that's the right thing to
16682 do. */
16687 /* Anonymous aggregates are a special case. */
16690 {
16693 {
16697 }
16699 }
16705 {
16710 }
16711 else
16712 {
16717 {
16718 /* For __PRETTY_FUNCTION__ we have to adjust the
16719 initializer. */
16723 }
16724 else
16728 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16733 {
16735 tree first;
16736 tree ndecl
16744 }
16745 else
16747 }
16748 }
16749 }
16752 }
16762 {
16766 }
16771 {
16772 /* Construct another range_for, if this is not a final
16773 substitution (for inside inside a generic lambda of a
16774 template). Otherwise convert to a regular for. */
16776 stmt = (processing_template_decl
16792 {
16796 }
16797 else
16798 {
16804 }
16810 }
16817 {
16821 }
16827 {
16831 }
16846 {
16847 /* We're partially instantiating a generic lambda, but the condition
16848 of the constexpr if is still dependent. Don't substitute into the
16849 branches now, just remember the template arguments. */
16857 }
16860 else
16861 {
16868 }
16874 {
16883 }
16891 else
16899 else
16920 {
16927 }
16931 {
16933 tree label;
16940 }
16946 /* Computed goto's must be tsubst'd into. On the other hand,
16947 non-computed gotos must not be; the identifier in question
16948 will have no binding. */
16950 else
16956 {
16972 }
16977 {
16982 }
16983 else
16984 {
16989 else
16996 else
17002 else
17004 }
17008 {
17012 {
17014 /* Prevent instantiate_decl from trying to instantiate
17015 this variable. We've already done all that needs to be
17016 done. */
17019 }
17024 }
17030 {
17031 /* Local classes are not independent templates; they are
17032 instantiated along with their containing function. And this
17033 way we don't have to deal with pushing out of one local class
17034 to instantiate a member of another local class. */
17035 /* Closures are handled by the LAMBDA_EXPR. */
17045 }
17049 {
17050 tree condition;
17053 condition =
17055 args,
17064 }
17070 in_decl);
17105 {
17118 in_decl);
17120 {
17127 }
17139 integral_constant_expression_p);
17150 else
17151 {
17159 }
17163 }
17168 /* FALLTHRU */
17175 in_decl);
17192 in_decl);
17203 {
17206 {
17207 /* For combined target teams, ensure the num_teams and
17208 thread_limit clause expressions are evaluated on the host,
17209 before entering the target construct. */
17210 tree c;
17216 {
17225 OMP_CLAUSE_FIRSTPRIVATE);
17229 }
17230 }
17231 }
17291 {
17296 {
17299 }
17305 }
17306 else
17307 {
17314 {
17317 }
17320 {
17325 {
17328 }
17334 }
17335 else
17336 {
17340 }
17343 }
17347 {
17353 {
17357 {
17362 }
17366 }
17367 else
17368 {
17373 }
17374 }
17378 {
17382 }
17395 /* If the first operand was a statement, we're done with it. */
17399 complain));
17413 integral_constant_expression_p));
17414 }
17417 out:
17420 #undef RECUR
17421 #undef RETURN
17422 }
17424 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17425 function. For description of the body see comment above
17426 cp_parser_omp_declare_reduction_exprs. */
17428 static void
17430 {
17436 tree_stmt_iterator tsi;
17447 {
17466 }
17468 {
17488 }
17489 }
17491 /* T is a postfix-expression that is not being used in a function
17492 call. Return the substituted version of T. */
17494 static tree
17496 tsubst_flags_t complain,
17497 tree in_decl)
17498 {
17502 else
17508 }
17510 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17511 instantiation context. Instantiating a pack expansion containing a lambda
17512 might result in multiple lambdas all based on the same lambda in the
17513 template. */
17515 tree
17517 {
17531 else
17539 {
17551 else
17556 {
17565 }
17566 else
17567 {
17573 }
17574 }
17580 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17598 else
17599 {
17600 /* Fix the type of 'this'. */
17606 {
17610 }
17611 else
17612 {
17616 }
17618 /* Let finish_function set this. */
17624 else
17625 /* Still increment function_depth so that we don't GC in the
17626 middle of an expression. */
17642 else
17645 /* The capture list was built up in reverse order; fix that now. */
17652 }
17659 }
17661 /* Like tsubst but deals with expressions and performs semantic
17662 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17664 tree
17666 tree args,
17667 tsubst_flags_t complain,
17668 tree in_decl,
17671 {
17672 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17673 #define RECUR(NODE) \
17674 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17676 integral_constant_expression_p)
17679 location_t loc;
17688 /* N3276 decltype magic only applies to calls at the top level or on the
17689 right side of a comma. */
17694 {
17697 /* Fall through. */
17699 {
17700 tree decl;
17701 cp_id_kind idk;
17706 {
17709 }
17711 /* Look up the name. */
17714 /* By convention, expressions use ERROR_MARK_NODE to indicate
17715 failure, not NULL_TREE. */
17721 integral_constant_expression_p,
17729 input_location);
17733 {
17737 }
17739 }
17742 {
17743 tree object;
17753 {
17758 }
17764 {
17767 }
17768 else
17775 else
17777 }
17780 {
17784 {
17785 /* A type conversion to reference type will be enclosed in
17786 such an indirect ref, but the substitution of the cast
17787 will have also added such an indirect ref. */
17789 }
17790 else
17798 }
17801 {
17805 }
17808 {
17812 {
17817 }
17819 /* We'll pass this to convert_nontype_argument again, we don't need
17820 to actually perform any conversion here. */
17826 flags));
17827 }
17830 {
17836 }
17843 {
17844 tree type;
17850 {
17855 }
17862 {
17880 }
17883 }
17916 else
17918 in_decl);
17953 {
17960 tree r = build_x_binary_op
17962 op0,
17964 ? ERROR_MARK
17966 op1,
17968 ? ERROR_MARK
17976 }
17979 {
17983 }
17999 /* Fall through */
18002 {
18003 tree r;
18011 {
18012 /* When there are no ARGS, we are trying to evaluate a
18013 non-dependent expression from the parser. Trying to do
18014 the substitutions may not work. */
18017 }
18018 else
18019 {
18024 else
18027 /*integral_constant_expression_p=*/
18031 }
18035 else
18039 {
18041 {
18043 {
18047 }
18048 else
18052 }
18054 }
18056 }
18059 {
18069 }
18085 {
18089 tree r = build_x_modify_expr
18092 /* TREE_NO_WARNING must be set if either the expression was
18093 parenthesized or it uses an operator such as >>= rather
18094 than plain assignment. In the former case, it was already
18095 set and must be copied. In the latter case,
18096 build_x_modify_expr sets it and it must not be reset
18097 here. */
18102 }
18107 /* Remember that there was a reference to this entity. */
18114 {
18119 tree ret;
18123 else
18124 {
18128 }
18130 /* If there was an initializer in the original tree, but it
18131 instantiated to an empty list, then we should pass a
18132 non-NULL empty vector to tell build_new that it was an
18133 empty initializer() rather than no initializer. This can
18134 only happen when the initializer is a pack expansion whose
18135 parameter packs are of length zero. */
18138 else
18139 {
18143 else
18144 {
18147 }
18148 }
18154 complain);
18162 }
18165 {
18171 complain));
18172 }
18175 {
18179 integral_constant_expression_p);
18181 op0,
18184 }
18187 {
18188 tree function;
18193 tree ret;
18196 /* Internal function with no arguments. */
18200 /* When we parsed the expression, we determined whether or
18201 not Koenig lookup should be performed. */
18204 {
18207 }
18209 {
18214 }
18216 {
18217 /* Do nothing; calling tsubst_copy_and_build on an identifier
18218 would incorrectly perform unqualified lookup again.
18220 Note that we can also have an IDENTIFIER_NODE if the earlier
18221 unqualified lookup found a member function; in that case
18222 koenig_p will be false and we do want to do the lookup
18223 again to find the instantiated member function.
18225 FIXME but doing that causes c++/15272, so we need to stop
18226 using IDENTIFIER_NODE in that situation. */
18228 }
18229 else
18230 {
18232 {
18238 }
18239 else
18244 /* Avoid error about taking the address of a constructor. */
18248 in_decl,
18250 integral_constant_expression_p);
18254 }
18259 {
18264 else
18265 {
18266 /* Expand the pack expansion and push each entry onto
18267 CALL_ARGS. */
18270 {
18275 {
18280 }
18281 }
18282 else
18283 {
18284 /* A partial substitution. Add one entry. */
18286 }
18287 }
18288 }
18290 /* We do not perform argument-dependent lookup if normal
18291 lookup finds a non-function, in accordance with the
18292 expected resolution of DR 218. */
18295 /* If lookup found a member function, the Koenig lookup is
18296 not appropriate, even if an unqualified-name was used
18297 to denote the function. */
18300 /* Only do this when substitution turns a dependent call
18301 into a non-dependent call. */
18309 {
18311 {
18312 /* For backwards compatibility and good diagnostics, try
18313 the unqualified lookup again if we aren't in SFINAE
18314 context. */
18315 tree unq = (tsubst_copy_and_build
18317 integral_constant_expression_p));
18319 {
18322 }
18325 {
18326 /* In a lambda fn, we have to be careful to not
18327 introduce new this captures. Legacy code can't
18328 be using lambdas anyway, so it's ok to be
18329 stricter. */
18334 "and no declarations were found by "
18335 "argument-dependent lookup at the point "
18342 else
18346 {
18357 {
18359 input_location);
18361 "declarations in dependent base %qT are "
18367 else
18371 }
18372 else
18374 "%qD declared here, later in the "
18377 {
18380 }
18381 }
18384 }
18385 }
18387 {
18392 }
18393 }
18395 /* Remember that there was a reference to this entity. */
18399 {
18402 }
18404 /* Put back tf_decltype for the actual call. */
18409 {
18413 {
18415 "wrong number of arguments to "
18418 }
18419 else
18421 input_location),
18426 /* Unsupported internal function with arguments. */
18428 }
18431 complain);
18433 {
18448 complain);
18449 else
18450 ret = (build_new_method_call
18455 complain));
18456 }
18457 else
18460 koenig_p,
18461 complain);
18466 {
18472 {
18478 {
18481 else
18483 /* The thunk location is not interesting. */
18485 }
18486 }
18487 }
18490 }
18493 {
18499 {
18501 {
18506 }
18507 else
18508 {
18513 }
18515 }
18516 else
18517 {
18520 }
18525 }
18528 {
18533 input_location));
18534 }
18537 {
18545 {
18546 /* We have pack expansions, so expand those and
18547 create a new list out of it. */
18550 tree chain;
18553 /* Expand the argument expressions. */
18561 /* Build the rest of the list. */
18566 /* Determine the number of arguments. */
18568 {
18571 }
18574 else
18575 {
18576 /* Since we only performed a partial substitution into
18577 the argument pack, we only RETURN (a single list
18578 node. */
18585 }
18587 /* Convert the argument vectors into a TREE_LIST */
18590 {
18591 /* Grab the Ith values. */
18592 i--;
18595 value
18599 /* Build the list (backwards). */
18601 }
18604 }
18620 }
18623 {
18624 tree object;
18625 tree object_type;
18626 tree member;
18627 tree r;
18631 /* Remember that there was a reference to this entity. */
18642 else
18648 {
18653 }
18657 {
18659 {
18664 {
18667 }
18669 {
18674 }
18675 }
18676 }
18679 {
18680 /* Lookup the template functions now that we know what the
18681 scope is. */
18689 {
18692 args);
18693 member = (adjust_result_of_qualified_name_lookup
18695 object_type));
18696 }
18697 else
18698 {
18700 input_location);
18702 }
18703 }
18707 {
18709 {
18713 else
18716 }
18718 }
18722 complain);
18726 }
18733 {
18741 tree r;
18746 /* We do not want to process the index of aggregate
18747 initializers as they are identifier nodes which will be
18748 looked up by digest_init. */
18754 {
18756 /* An identifier index is looked up in the type
18757 being initialized, not the current scope. */
18762 {
18763 /* Substitute into the pack expansion. */
18765 in_decl);
18769 ;
18771 /* Just move the argument into place. */
18773 else
18774 {
18775 /* Update the length of the final CONSTRUCTOR
18776 arguments vector, and note that we will need to
18777 copy.*/
18780 }
18781 }
18782 else
18784 }
18787 {
18792 {
18794 {
18799 }
18800 else
18802 }
18803 }
18809 {
18814 }
18818 }
18821 {
18824 {
18827 }
18828 else
18829 {
18832 }
18833 }
18838 /* Fall through */
18841 {
18843 /* ??? We're doing a subset of finish_id_expression here. */
18845 && !processing_template_decl
18846 && !cp_unevaluated_operand
18849 {
18851 /* Replace an evaluated use of the thread_local variable with
18852 a call to its wrapper. */
18854 }
18859 /* If the original type was a reference, we'll be wrapped in
18860 the appropriate INDIRECT_REF. */
18863 }
18866 {
18870 }
18873 {
18874 tree object_ptr
18881 }
18888 {
18899 }
18902 {
18908 integral_constant_expression_p);
18912 /* If the resulting list of expression statement is empty,
18913 fold it further into void_node. */
18918 }
18921 {
18925 }
18928 /* We can get here for a constant initializer of non-dependent type.
18929 FIXME stop folding in cp_parser_initializer_clause. */
18930 {
18932 complain);
18934 }
18938 integral_constant_expression_p));
18944 {
18949 complain));
18950 }
18957 /* We should only see these for location wrapper nodes, or within
18958 instantiate_non_dependent_expr (when args is NULL_TREE). */
18963 /* fallthrough. */
18966 /* Handle Objective-C++ constructs, if appropriate. */
18967 {
18968 tree subst
18973 }
18975 }
18977 #undef RECUR
18978 #undef RETURN
18979 out:
18982 }
18984 /* Verify that the instantiated ARGS are valid. For type arguments,
18985 make sure that the type's linkage is ok. For non-type arguments,
18986 make sure they are constants if they are integral or enumerations.
18987 Emit an error under control of COMPLAIN, and return TRUE on error. */
18989 static bool
18991 {
18995 {
19005 }
19007 {
19008 /* [basic.link]: A name with no linkage (notably, the name
19009 of a class or enumeration declared in a local scope)
19010 shall not be used to declare an entity with linkage.
19011 This implies that names with no linkage cannot be used as
19012 template arguments
19014 DR 757 relaxes this restriction for C++0x. */
19019 {
19020 /* DR 488 makes use of a type with no linkage cause
19021 type deduction to fail. */
19023 {
19026 else
19029 }
19031 }
19032 /* In order to avoid all sorts of complications, we do not
19033 allow variably-modified types as template arguments. */
19035 {
19039 }
19040 }
19041 /* Class template and alias template arguments should be OK. */
19043 ;
19044 /* A non-type argument of integral or enumerated type must be a
19045 constant. */
19050 {
19054 }
19056 }
19058 static bool
19060 {
19065 {
19068 }
19072 }
19074 /* We're out of SFINAE context now, so generate diagnostics for the access
19075 errors we saw earlier when instantiating D from TMPL and ARGS. */
19077 static void
19079 {
19091 }
19093 /* Instantiate the indicated variable, function, or alias template TMPL with
19094 the template arguments in TARG_PTR. */
19096 static tree
19098 {
19100 tree fndecl;
19101 tree gen_tmpl;
19102 tree spec;
19110 /* If this function is a clone, handle it specially. */
19112 {
19113 tree spec;
19114 tree clone;
19116 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
19117 DECL_CLONED_FUNCTION. */
19123 /* Look for the clone. */
19127 /* We should always have found the clone by now. */
19130 }
19135 /* Check to see if we already have this specialization. */
19139 /* targ_ptr only has the innermost template args, so add the outer ones
19140 from tmpl, which could be either a partial instantiation or gen_tmpl (in
19141 the case of a non-dependent call within a template definition). */
19142 targ_ptr = (add_outermost_template_args
19144 targ_ptr));
19146 /* It would be nice to avoid hashing here and then again in tsubst_decl,
19147 but it doesn't seem to be on the hot path. */
19156 {
19158 {
19162 }
19164 }
19167 complain))
19170 /* We are building a FUNCTION_DECL, during which the access of its
19171 parameters and return types have to be checked. However this
19172 FUNCTION_DECL which is the desired context for access checking
19173 is not built yet. We solve this chicken-and-egg problem by
19174 deferring all checks until we have the FUNCTION_DECL. */
19177 /* Instantiation of the function happens in the context of the function
19178 template, not the context of the overload resolution we're doing. */
19180 /* If there are dependent arguments, e.g. because we're doing partial
19181 ordering, make sure processing_template_decl stays set. */
19185 {
19189 }
19195 {
19196 /* We need to determine if we're using a partial or explicit
19197 specialization now, because the type of the variable could be
19198 different. */
19204 {
19209 }
19210 }
19212 /* Substitute template parameters to obtain the specialization. */
19220 {
19223 }
19225 /* The DECL_TI_TEMPLATE should always be the immediate parent
19226 template, not the most general template. */
19230 /* Now we know the specialization, compute access previously
19231 deferred. Do no access control for inheriting constructors,
19232 as we already checked access for the inherited constructor. */
19235 {
19240 }
19243 /* If we've just instantiated the main entry point for a function,
19244 instantiate all the alternate entry points as well. We do this
19245 by cloning the instantiation of the main entry point, not by
19246 instantiating the template clones. */
19251 {
19253 {
19254 /* Remember to reinstantiate when we're out of SFINAE so the user
19255 can see the errors. */
19257 }
19259 }
19261 }
19263 /* Wrapper for instantiate_template_1. */
19265 tree
19267 {
19268 tree ret;
19273 }
19275 /* Instantiate the alias template TMPL with ARGS. Also push a template
19276 instantiation level, which instantiate_template doesn't do because
19277 functions and variables have sufficient context established by the
19278 callers. */
19280 static tree
19282 {
19288 args =
19298 }
19300 /* PARM is a template parameter pack for FN. Returns true iff
19301 PARM is used in a deducible way in the argument list of FN. */
19303 static bool
19305 {
19308 {
19310 tree packs;
19316 {
19317 /* The template parameter pack is used in a function parameter
19318 pack. If this is the end of the parameter list, the
19319 template parameter pack is deducible. */
19322 else
19323 /* Otherwise, not. Well, it could be deduced from
19324 a non-pack parameter, but doing so would end up with
19325 a deduction mismatch, so don't bother. */
19327 }
19328 }
19329 /* The template parameter pack isn't used in any function parameter
19330 packs, but it might be used deeper, e.g. tuple<Args...>. */
19332 }
19334 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
19335 NARGS elements of the arguments that are being used when calling
19336 it. TARGS is a vector into which the deduced template arguments
19337 are placed.
19339 Returns either a FUNCTION_DECL for the matching specialization of FN or
19340 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
19341 true, diagnostics will be printed to explain why it failed.
19343 If FN is a conversion operator, or we are trying to produce a specific
19344 specialization, RETURN_TYPE is the return type desired.
19346 The EXPLICIT_TARGS are explicit template arguments provided via a
19347 template-id.
19349 The parameter STRICT is one of:
19351 DEDUCE_CALL:
19352 We are deducing arguments for a function call, as in
19353 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
19354 deducing arguments for a call to the result of a conversion
19355 function template, as in [over.call.object].
19357 DEDUCE_CONV:
19358 We are deducing arguments for a conversion function, as in
19359 [temp.deduct.conv].
19361 DEDUCE_EXACT:
19362 We are deducing arguments when doing an explicit instantiation
19363 as in [temp.explicit], when determining an explicit specialization
19364 as in [temp.expl.spec], or when taking the address of a function
19365 template, as in [temp.deduct.funcaddr]. */
19367 tree
19369 tree explicit_targs,
19370 tree targs,
19373 tree return_type,
19374 unification_kind_t strict,
19378 {
19379 tree parms;
19380 tree fntype;
19396 full_targs = (add_outermost_template_args
19398 targs));
19403 /* In C++0x, it's possible to have a function template whose type depends
19404 on itself recursively. This is most obvious with decltype, but can also
19405 occur with enumeration scope (c++/48969). So we need to catch infinite
19406 recursion and reject the substitution at deduction time; this function
19407 will return error_mark_node for any repeated substitution.
19409 This also catches excessive recursion such as when f<N> depends on
19410 f<N-1> across all integers, and returns error_mark_node for all the
19411 substitutions back up to the initial one.
19413 This is, of course, not reentrant. */
19422 {
19423 /* [temp.deduct]
19425 The specified template arguments must match the template
19426 parameters in kind (i.e., type, nontype, template), and there
19427 must not be more arguments than there are parameters;
19428 otherwise type deduction fails.
19430 Nontype arguments must match the types of the corresponding
19431 nontype template parameters, or must be convertible to the
19432 types of the corresponding nontype parameters as specified in
19433 _temp.arg.nontype_, otherwise type deduction fails.
19435 All references in the function type of the function template
19436 to the corresponding template parameters are replaced by the
19437 specified template argument values. If a substitution in a
19438 template parameter or in the function type of the function
19439 template results in an invalid type, type deduction fails. */
19450 explicit_targs);
19452 /* Adjust any explicit template arguments before entering the
19453 substitution context. */
19454 explicit_targs
19456 complain,
19462 /* Substitute the explicit args into the function type. This is
19463 necessary so that, for instance, explicitly declared function
19464 arguments can match null pointed constants. If we were given
19465 an incomplete set of explicit args, we must not do semantic
19466 processing during substitution as we could create partial
19467 instantiations. */
19469 {
19474 /* Dig out the actual parm. */
19477 {
19480 }
19482 {
19485 }
19488 /* No explicit argument for this template parameter. */
19492 {
19493 /* Mark the argument pack as "incomplete". We could
19494 still deduce more arguments during unification.
19495 We remove this mark in type_unification_real. */
19497 {
19501 }
19503 /* We have some incomplete argument packs. */
19505 }
19506 }
19509 {
19512 }
19515 /* Ignore any access checks; we'll see them again in
19516 instantiate_template and they might have the wrong
19517 access path at this point. */
19529 /* Place the explicitly specified arguments in TARGS. */
19533 }
19535 /* Never do unification on the 'this' parameter. */
19539 {
19540 /* We're deducing for a call to the result of a template conversion
19541 function. The parms we really want are in return_type. */
19545 }
19547 {
19556 }
19558 /* We allow incomplete unification without an error message here
19559 because the standard doesn't seem to explicitly prohibit it. Our
19560 callers must be ready to deal with unification failures in any
19561 event. */
19563 /* If we aren't explaining yet, push tinst context so we can see where
19564 any errors (e.g. from class instantiations triggered by instantiation
19565 of default template arguments) come from. If we are explaining, this
19566 context is redundant. */
19568 {
19571 }
19573 /* type_unification_real will pass back any access checks from default
19574 template argument substitution. */
19586 /* Now that we have bindings for all of the template arguments,
19587 ensure that the arguments deduced for the template template
19588 parameters have compatible template parameter lists. We cannot
19589 check this property before we have deduced all template
19590 arguments, because the template parameter types of a template
19591 template parameter might depend on prior template parameters
19592 deduced after the template template parameter. The following
19593 ill-formed example illustrates this issue:
19595 template<typename T, template<T> class C> void f(C<5>, T);
19597 template<int N> struct X {};
19599 void g() {
19600 f(X<5>(), 5l); // error: template argument deduction fails
19601 }
19603 The template parameter list of 'C' depends on the template type
19604 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19605 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19606 time that we deduce 'C'. */
19609 {
19612 }
19614 /* All is well so far. Now, check:
19616 [temp.deduct]
19618 When all template arguments have been deduced, all uses of
19619 template parameters in nondeduced contexts are replaced with
19620 the corresponding deduced argument values. If the
19621 substitution results in an invalid type, as described above,
19622 type deduction fails. */
19624 {
19627 }
19629 /* Also collect access checks from the instantiation. */
19642 /* Now perform any access checks encountered during substitution. */
19649 /* If we're looking for an exact match, check that what we got
19650 is indeed an exact match. It might not be if some template
19651 parameters are used in non-deduced contexts. But don't check
19652 for an exact match if we have dependent template arguments;
19653 in that case we're doing partial ordering, and we already know
19654 that we have two candidates that will provide the actual type. */
19656 {
19660 tree sarg
19666 {
19670 }
19671 }
19673 /* After doing deduction with the inherited constructor, actually return an
19674 instantiation of the inheriting constructor. */
19680 fail:
19683 {
19685 /* Reset once we're all the way out. */
19687 }
19690 }
19692 /* Adjust types before performing type deduction, as described in
19693 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19694 sections are symmetric. PARM is the type of a function parameter
19695 or the return type of the conversion function. ARG is the type of
19696 the argument passed to the call, or the type of the value
19697 initialized with the result of the conversion function.
19698 ARG_EXPR is the original argument expression, which may be null. */
19700 static int
19704 tree arg_expr)
19705 {
19709 {
19714 /* Swap PARM and ARG throughout the remainder of this
19715 function; the handling is precisely symmetric since PARM
19716 will initialize ARG rather than vice versa. */
19721 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19722 too, but here handle it by stripping the reference from PARM
19723 rather than by adding it to ARG. */
19731 /* Nothing else to do in this case. */
19736 }
19739 {
19740 /* [temp.deduct.call]
19742 If P is not a reference type:
19744 --If A is an array type, the pointer type produced by the
19745 array-to-pointer standard conversion (_conv.array_) is
19746 used in place of A for type deduction; otherwise,
19748 --If A is a function type, the pointer type produced by
19749 the function-to-pointer standard conversion
19750 (_conv.func_) is used in place of A for type deduction;
19751 otherwise,
19753 --If A is a cv-qualified type, the top level
19754 cv-qualifiers of A's type are ignored for type
19755 deduction. */
19760 else
19762 }
19764 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19765 reference to a cv-unqualified template parameter that does not represent a
19766 template parameter of a class template (during class template argument
19767 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19768 an lvalue, the type "lvalue reference to A" is used in place of A for type
19769 deduction. */
19776 /* try_one_overload doesn't provide an arg_expr, but
19777 functions are always lvalues. */
19781 /* [temp.deduct.call]
19783 If P is a cv-qualified type, the top level cv-qualifiers
19784 of P's type are ignored for type deduction. If P is a
19785 reference type, the type referred to by P is used for
19786 type deduction. */
19789 {
19792 }
19794 /* DR 322. For conversion deduction, remove a reference type on parm
19795 too (which has been swapped into ARG). */
19800 }
19802 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19803 template which does contain any deducible template parameters; check if
19804 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19805 unify_one_argument. */
19807 static int
19810 {
19811 tree type;
19815 else
19822 {
19826 }
19828 {
19833 }
19837 else
19839 }
19843 /* Returns true iff the expression EXPR is one from which a template
19844 argument can be deduced. In other words, if it's an undecorated
19845 use of a template non-type parameter. */
19847 static bool
19849 {
19850 /* Strip implicit conversions. */
19854 }
19856 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19857 deducible way; that is, if it has a max value of <PARM> - 1. */
19859 static bool
19861 {
19870 }
19872 /* Returns true iff the template arguments ARGS use a template parameter
19873 in a deducible way. */
19875 static bool
19877 {
19879 {
19884 else
19885 {
19892 else
19894 }
19897 }
19899 }
19901 /* Returns true iff TYPE contains any deducible references to template
19902 parameters, as per 14.8.2.5. */
19904 static bool
19906 {
19910 /* T
19911 cv-list T
19912 TT<T>
19913 TT<i>
19914 TT<> */
19919 /* T*
19920 T&
19921 T&& */
19925 /* T[integer-constant ]
19926 type [i] */
19931 /* T type ::*
19932 type T::*
19933 T T::*
19934 T (type ::*)()
19935 type (T::*)()
19936 type (type ::*)(T)
19937 type (T::*)(T)
19938 T (type ::*)(T)
19939 T (T::*)()
19940 T (T::*)(T) */
19943 || (uses_deducible_template_parms
19946 /* template-name <T> (where template-name refers to a class template)
19947 template-name <i> (where template-name refers to a class template) */
19954 /* type (T)
19955 T()
19956 T(T) */
19959 {
19968 }
19971 }
19973 /* Subroutine of type_unification_real and unify_pack_expansion to
19974 handle unification of a single P/A pair. Parameters are as
19975 for those functions. */
19977 static int
19981 {
19988 /* We can't deduce anything from this, but we might get all the
19989 template args from other function args. */
19992 /* Implicit conversions (Clause 4) will be performed on a function
19993 argument to convert it to the type of the corresponding function
19994 parameter if the parameter type contains no template-parameters that
19995 participate in template argument deduction. */
19998 /* For function parameters with no deducible template parameters,
19999 just return. We'll check non-dependent conversions later. */
20003 {
20005 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
20006 | UNIFY_ALLOW_MORE_CV_QUAL
20020 }
20022 /* We only do these transformations if this is the top-level
20023 parameter_type_list in a call or declaration matching; in other
20024 situations (nested function declarators, template argument lists) we
20025 won't be comparing a type to an expression, and we don't do any type
20026 adjustments. */
20028 {
20030 {
20033 {
20034 /* [temp.deduct.type] A template-argument can be
20035 deduced from a pointer to function or pointer
20036 to member function argument if the set of
20037 overloaded functions does not contain function
20038 templates and at most one of a set of
20039 overloaded functions provides a unique
20040 match. */
20044 /* If a unique match was not found, this is a
20045 non-deduced context, so we still succeed. */
20047 }
20053 }
20055 arg_strict |=
20057 }
20058 else
20063 /* For deduction from an init-list we need the actual list. */
20067 }
20069 /* for_each_template_parm callback that always returns 0. */
20071 static int
20073 {
20075 }
20077 /* for_each_template_parm any_fn callback to handle deduction of a template
20078 type argument from the type of an array bound. */
20080 static int
20082 {
20090 {
20096 }
20098 /* Keep walking. */
20100 }
20102 /* Try to deduce any not-yet-deduced template type arguments from the type of
20103 an array bound. This is handled separately from unify because 14.8.2.5 says
20104 "The type of a type parameter is only deduced from an array bound if it is
20105 not otherwise deduced." */
20107 static void
20109 {
20114 }
20116 /* Most parms like fn_type_unification.
20118 If SUBR is 1, we're being called recursively (to unify the
20119 arguments of a function or method parameter of a function
20120 template).
20122 CHECKS is a pointer to a vector of access checks encountered while
20123 substituting default template arguments. */
20125 static int
20127 tree full_targs,
20128 tree xparms,
20132 unification_kind_t strict,
20136 {
20141 tree parms;
20152 /* Reset the number of non-defaulted template arguments contained
20153 in TARGS. */
20156 again:
20164 {
20169 /* For a function parameter pack that occurs at the end of the
20170 parameter-declaration-list, the type A of each remaining
20171 argument of the call is compared with the type P of the
20172 declarator-id of the function parameter pack. */
20178 /* For a function parameter pack that does not occur at the
20179 end of the parameter-declaration-list, the type of the
20180 parameter pack is a non-deduced context. */
20187 explain_p))
20189 }
20194 {
20195 /* Unify the remaining arguments with the pack expansion type. */
20196 tree argvec;
20199 /* Allocate a TREE_VEC and copy in all of the arguments */
20204 /* Copy the parameter into parmvec. */
20210 /* Advance to the end of the list of parameters. */
20212 }
20214 /* Fail if we've reached the end of the parm list, and more args
20215 are present, and the parm list isn't variadic. */
20218 /* Fail if parms are left and they don't have default values and
20219 they aren't all deduced as empty packs (c++/57397). This is
20220 consistent with sufficient_parms_p. */
20223 {
20227 do
20228 {
20231 count++;
20233 }
20237 type_pack_p);
20238 }
20241 {
20242 tsubst_flags_t complain = (explain_p
20243 ? tf_warning_or_error
20248 {
20252 /* Clear the "incomplete" flags on all argument packs now so that
20253 substituting them into later default arguments works. */
20255 {
20258 }
20266 {
20271 }
20273 /* If this is an undeduced nontype parameter that depends on
20274 a type parameter, try another pass; its type may have been
20275 deduced from a later argument than the one from which
20276 this parameter can be deduced. */
20280 {
20283 }
20285 /* Core issue #226 (C++0x) [temp.deduct]:
20287 If a template argument has not been deduced, its
20288 default template argument, if any, is used.
20290 When we are in C++98 mode, TREE_PURPOSE will either
20291 be NULL_TREE or ERROR_MARK_NODE, so we do not need
20292 to explicitly check cxx_dialect here. */
20294 /* OK, there is a default argument. Wait until after the
20295 conversion check to do substitution. */
20298 /* If the type parameter is a parameter pack, then it will
20299 be deduced to an empty parameter pack. */
20301 {
20302 tree arg;
20305 {
20308 }
20309 else
20316 }
20319 }
20321 /* DR 1391: All parameters have args, now check non-dependent parms for
20322 convertibility. */
20326 {
20332 /* For a function parameter pack that occurs at the end of the
20333 parameter-declaration-list, the type A of each remaining
20334 argument of the call is compared with the type P of the
20335 declarator-id of the function parameter pack. */
20341 /* For a function parameter pack that does not occur at the
20342 end of the parameter-declaration-list, the type of the
20343 parameter pack is a non-deduced context. */
20352 explain_p))
20354 }
20356 /* Now substitute into the default template arguments. */
20358 {
20376 {
20377 /* The type of this non-type parameter depends on undeduced
20378 parameters. Don't try to use its default argument yet,
20379 but do check whether the arguments we already have cause
20380 substitution failure, so that that happens before we try
20381 later default arguments (78489). */
20383 NULL_TREE);
20386 else
20388 }
20389 else
20390 {
20398 else
20400 }
20411 {
20413 /* The position of the first default template argument,
20414 is also the number of non-defaulted arguments in TARGS.
20415 Record that. */
20418 }
20419 }
20423 }
20429 }
20431 /* Subroutine of type_unification_real. Args are like the variables
20432 at the call site. ARG is an overloaded function (or template-id);
20433 we try deducing template args from each of the overloads, and if
20434 only one succeeds, we go with that. Modifies TARGS and returns
20435 true on success. */
20437 static bool
20439 tree targs,
20440 tree parm,
20441 tree arg,
20442 unification_kind_t strict,
20445 {
20452 {
20455 }
20456 else
20460 /* Handle `&x' where `x' is some static or non-static member
20461 function name. */
20467 /* Strip baselink information. */
20472 {
20473 /* If we got some explicit template args, we need to plug them into
20474 the affected templates before we try to unify, in case the
20475 explicit args will completely resolve the templates in question. */
20482 {
20495 {
20500 {
20503 }
20504 }
20507 }
20508 /* If no templates (or more than one) are fully resolved by the
20509 explicit arguments, this template-id is a non-deduced context; it
20510 could still be OK if we deduce all template arguments for the
20511 enclosing call through other arguments. */
20514 }
20517 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20518 -- but the deduction does not succeed because the expression is
20519 not just the function on its own. */
20521 else
20523 {
20528 {
20531 }
20532 }
20534 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20535 to function or pointer to member function argument if the set of
20536 overloaded functions does not contain function templates and at most
20537 one of a set of overloaded functions provides a unique match.
20539 So if we found multiple possibilities, we return success but don't
20540 deduce anything. */
20543 {
20547 {
20552 /* Don't forget explicit template arguments in a pack. */
20556 }
20557 }
20562 }
20564 /* Core DR 115: In contexts where deduction is done and fails, or in
20565 contexts where deduction is not done, if a template argument list is
20566 specified and it, along with any default template arguments, identifies
20567 a single function template specialization, then the template-id is an
20568 lvalue for the function template specialization. */
20570 tree
20572 {
20585 {
20588 }
20590 {
20593 }
20595 {
20598 }
20601 {
20605 /* If we got some explicit template args, we need to plug them into
20606 the affected templates before we try to unify, in case the
20607 explicit args will completely resolve the templates in question. */
20615 {
20628 {
20631 {
20634 }
20636 {
20639 }
20640 }
20641 }
20643 {
20651 {
20652 tree base
20655 }
20659 }
20661 /* There were no good options and at least one bad one, so let the
20662 user know what the problem is. */
20664 }
20666 }
20668 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20669 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20670 different overloads deduce different arguments for a given parm.
20671 ADDR_P is true if the expression for which deduction is being
20672 performed was of the form "& fn" rather than simply "fn".
20674 Returns 1 on success. */
20676 static int
20678 tree orig_targs,
20679 tree targs,
20680 tree parm,
20681 tree arg,
20682 unification_kind_t strict,
20686 {
20688 tree tempargs;
20694 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20695 to function or pointer to member function argument if the set of
20696 overloaded functions does not contain function templates and at most
20697 one of a set of overloaded functions provides a unique match.
20699 So if this is a template, just return success. */
20711 /* We don't copy orig_targs for this because if we have already deduced
20712 some template args from previous args, unify would complain when we
20713 try to deduce a template parameter for the same argument, even though
20714 there isn't really a conflict. */
20721 /* First make sure we didn't deduce anything that conflicts with
20722 explicitly specified args. */
20724 {
20731 /* Since we're unifying against ourselves, we will fill in
20732 template args used in the function parm list with our own
20733 template parms. Discard them. */
20736 {
20737 /* Check that the argument at each index of the deduced argument pack
20738 is equivalent to the corresponding explicitly specified argument.
20739 We may have deduced more arguments than were explicitly specified,
20740 and that's OK. */
20742 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20743 that's wrong if we deduce the same argument pack from multiple
20744 function arguments: it's only incomplete the first time. */
20757 }
20760 }
20763 {
20768 }
20771 }
20773 /* PARM is a template class (perhaps with unbound template
20774 parameters). ARG is a fully instantiated type. If ARG can be
20775 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20776 TARGS are as for unify. */
20778 static tree
20781 {
20782 tree copy_of_targs;
20792 /* We need to make a new template argument vector for the call to
20793 unify. If we used TARGS, we'd clutter it up with the result of
20794 the attempted unification, even if this class didn't work out.
20795 We also don't want to commit ourselves to all the unifications
20796 we've already done, since unification is supposed to be done on
20797 an argument-by-argument basis. In other words, consider the
20798 following pathological case:
20800 template <int I, int J, int K>
20801 struct S {};
20803 template <int I, int J>
20804 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20806 template <int I, int J, int K>
20807 void f(S<I, J, K>, S<I, I, I>);
20809 void g() {
20810 S<0, 0, 0> s0;
20811 S<0, 1, 2> s2;
20813 f(s0, s2);
20814 }
20816 Now, by the time we consider the unification involving `s2', we
20817 already know that we must have `f<0, 0, 0>'. But, even though
20818 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20819 because there are two ways to unify base classes of S<0, 1, 2>
20820 with S<I, I, I>. If we kept the already deduced knowledge, we
20821 would reject the possibility I=1. */
20825 {
20829 }
20831 /* If unification failed, we're done. */
20837 }
20839 /* Given a template type PARM and a class type ARG, find the unique
20840 base type in ARG that is an instance of PARM. We do not examine
20841 ARG itself; only its base-classes. If there is not exactly one
20842 appropriate base class, return NULL_TREE. PARM may be the type of
20843 a partial specialization, as well as a plain template type. Used
20844 by unify. */
20846 static enum template_base_result
20849 {
20851 tree binfo;
20857 {
20858 /* The type could not be completed. */
20861 }
20863 /* Walk in inheritance graph order. The search order is not
20864 important, and this avoids multiple walks of virtual bases. */
20866 {
20871 {
20872 /* If there is more than one satisfactory baseclass, then:
20874 [temp.deduct.call]
20876 If they yield more than one possible deduced A, the type
20877 deduction fails.
20879 applies. */
20881 {
20884 }
20887 }
20888 }
20892 }
20894 /* Returns the level of DECL, which declares a template parameter. */
20896 static int
20898 {
20900 {
20910 }
20912 }
20914 /* Decide whether ARG can be unified with PARM, considering only the
20915 cv-qualifiers of each type, given STRICT as documented for unify.
20916 Returns nonzero iff the unification is OK on that basis. */
20918 static int
20920 {
20926 {
20927 /* Although a CVR qualifier is ignored when being applied to a
20928 substituted template parameter ([8.3.2]/1 for example), that
20929 does not allow us to unify "const T" with "int&" because both
20930 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20931 It is ok when we're allowing additional CV qualifiers
20932 at the outer level [14.8.2.1]/3,1st bullet. */
20942 }
20953 }
20955 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20956 void
20958 {
20962 {
20965 }
20966 else
20967 {
20970 }
20971 }
20973 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20974 do { \
20975 if (unify (TP, TA, P, A, S, EP)) \
20976 return 1; \
20977 } while (0)
20979 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20980 expansion at the end of PACKED_PARMS. Returns 0 if the type
20981 deduction succeeds, 1 otherwise. STRICT is the same as in
20982 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20983 function call argument list. We'll need to adjust the arguments to make them
20984 types. SUBR tells us if this is from a recursive call to
20985 type_unification_real, or for comparing two template argument
20986 lists. */
20988 static int
20992 {
20993 tree parm
20999 /* Add in any args remembered from an earlier partial instantiation. */
21007 /* Determine the parameter packs we will be deducing from the
21008 pattern, and record their current deductions. */
21011 {
21015 /* Only template parameter packs can be deduced, not e.g. function
21016 parameter packs or __bases or __integer_pack. */
21020 /* Determine the index and level of this parameter pack. */
21025 /* Keep track of the parameter packs and their corresponding
21026 argument packs. */
21029 }
21031 /* Loop through all of the arguments that have not yet been
21032 unified and unify each with the pattern. */
21034 {
21035 tree parm;
21039 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
21040 or the element of its argument pack at the current index if
21041 this argument was explicitly specified. */
21043 {
21052 {
21055 }
21057 }
21059 /* If we had explicit template arguments, substitute them into the
21060 pattern before deduction. */
21062 {
21063 /* Some arguments might still be unspecified or dependent. */
21071 NULL_TREE);
21076 }
21077 else
21080 /* Unify the pattern with the current argument. */
21082 explain_p))
21085 /* For each parameter pack, collect the deduced value. */
21087 {
21093 }
21094 }
21096 /* Verify that the results of unification with the parameter packs
21097 produce results consistent with what we've seen before, and make
21098 the deduced argument packs available. */
21100 {
21107 /* By default keep the original deduced argument pack.
21108 If necessary, more specific code is going to update the
21109 resulting deduced argument later down in this function. */
21113 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
21114 actually deduce anything. */
21122 {
21123 /* If we had fewer function args than explicit template args,
21124 just use the explicits. */
21129 }
21132 {
21133 tree result;
21134 /* Build the deduced *_ARGUMENT_PACK. */
21136 {
21139 }
21140 else
21145 /* Note the deduced argument packs for this parameter
21146 pack. */
21148 }
21152 {
21153 /* We only had the explicitly-provided arguments before, but
21154 now we have a complete set of arguments. */
21160 }
21161 else
21162 {
21168 /* Inconsistent unification of this parameter pack. */
21170 bad_old_arg,
21171 bad_new_arg);
21172 }
21173 }
21176 }
21178 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
21179 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
21180 parameters and return value are as for unify. */
21182 static int
21186 {
21187 tree parm_max;
21188 tree arg_max;
21192 /* Our representation of array types uses "N - 1" as the
21193 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
21194 not an integer constant. We cannot unify arbitrarily
21195 complex expressions, so we eliminate the MINUS_EXPRs
21196 here. */
21200 {
21203 }
21207 {
21208 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
21209 trying to unify the type of a variable with the type
21210 of a template parameter. For example:
21212 template <unsigned int N>
21213 void f (char (&) [N]);
21214 int g();
21215 void h(int i) {
21216 char a[g(i)];
21217 f(a);
21218 }
21220 Here, the type of the ARG will be "int [g(i)]", and
21221 may be a SAVE_EXPR, etc. */
21225 }
21227 /* If only one of the bounds used a MINUS_EXPR, compensate
21228 by adding one to the other bound. */
21231 integer_type_node,
21232 parm_max,
21233 integer_one_node);
21236 integer_type_node,
21237 arg_max,
21238 integer_one_node);
21242 }
21244 /* Returns whether T, a P or A in unify, is a type, template or expression. */
21248 static pa_kind_t
21250 {
21259 else
21261 }
21263 /* Deduce the value of template parameters. TPARMS is the (innermost)
21264 set of template parameters to a template. TARGS is the bindings
21265 for those template parameters, as determined thus far; TARGS may
21266 include template arguments for outer levels of template parameters
21267 as well. PARM is a parameter to a template function, or a
21268 subcomponent of that parameter; ARG is the corresponding argument.
21269 This function attempts to match PARM with ARG in a manner
21270 consistent with the existing assignments in TARGS. If more values
21271 are deduced, then TARGS is updated.
21273 Returns 0 if the type deduction succeeds, 1 otherwise. The
21274 parameter STRICT is a bitwise or of the following flags:
21276 UNIFY_ALLOW_NONE:
21277 Require an exact match between PARM and ARG.
21278 UNIFY_ALLOW_MORE_CV_QUAL:
21279 Allow the deduced ARG to be more cv-qualified (by qualification
21280 conversion) than ARG.
21281 UNIFY_ALLOW_LESS_CV_QUAL:
21282 Allow the deduced ARG to be less cv-qualified than ARG.
21283 UNIFY_ALLOW_DERIVED:
21284 Allow the deduced ARG to be a template base class of ARG,
21285 or a pointer to a template base class of the type pointed to by
21286 ARG.
21287 UNIFY_ALLOW_INTEGER:
21288 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
21289 case for more information.
21290 UNIFY_ALLOW_OUTER_LEVEL:
21291 This is the outermost level of a deduction. Used to determine validity
21292 of qualification conversions. A valid qualification conversion must
21293 have const qualified pointers leading up to the inner type which
21294 requires additional CV quals, except at the outer level, where const
21295 is not required [conv.qual]. It would be normal to set this flag in
21296 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
21297 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
21298 This is the outermost level of a deduction, and PARM can be more CV
21299 qualified at this point.
21300 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
21301 This is the outermost level of a deduction, and PARM can be less CV
21302 qualified at this point. */
21304 static int
21307 {
21309 tree targ;
21310 tree tparm;
21312 tsubst_flags_t complain = (explain_p
21313 ? tf_warning_or_error
21316 /* I don't think this will do the right thing with respect to types.
21317 But the only case I've seen it in so far has been array bounds, where
21318 signedness is the only information lost, and I think that will be
21319 okay. */
21327 /* We can't deduce anything from this, but we might get all the
21328 template args from other function args. */
21334 /* If PARM uses template parameters, then we can't bail out here,
21335 even if ARG == PARM, since we won't record unifications for the
21336 template parameters. We might need them if we're trying to
21337 figure out which of two things is more specialized. */
21341 /* Handle init lists early, so the rest of the function can assume
21342 we're dealing with a type. */
21344 {
21349 /* Replace T with std::initializer_list<T> for deduction. */
21356 /* We can only deduce from an initializer list argument if the
21357 parameter is std::initializer_list or an array; otherwise this
21358 is a non-deduced context. */
21363 else
21364 {
21366 /* Deduction is defined in terms of a single type, so just punt
21367 on the (bizarre) std::initializer_list<T...>. */
21370 }
21373 {
21380 {
21384 /* It should only be possible to get here for a call. */
21386 elt_strict |= maybe_adjust_types_for_deduction
21389 }
21392 explain_p);
21393 }
21397 {
21398 /* Also deduce from the length of the initializer list. */
21405 }
21407 /* If the std::initializer_list<T> deduction worked, replace the
21408 deduced A with std::initializer_list<A>. */
21410 {
21415 }
21417 }
21419 /* If parm and arg aren't the same kind of thing (template, type, or
21420 expression), fail early. */
21424 /* Immediately reject some pairs that won't unify because of
21425 cv-qualification mismatches. */
21428 /* It is the elements of the array which hold the cv quals of an array
21429 type, and the elements might be template type parms. We'll check
21430 when we recurse. */
21432 /* We check the cv-qualifiers when unifying with template type
21433 parameters below. We want to allow ARG `const T' to unify with
21434 PARM `T' for example, when computing which of two templates
21435 is more specialized, for example. */
21449 {
21453 /* In a type which contains a nested-name-specifier, template
21454 argument values cannot be deduced for template parameters used
21455 within the nested-name-specifier. */
21467 /* The PARM is not one we're trying to unify. Just check
21468 to see if it matches ARG. */
21469 {
21474 else
21476 }
21483 /* Check for mixed types and values. */
21491 {
21494 {
21495 /* First try to match ARG directly. */
21497 explain_p);
21499 {
21500 /* Otherwise, look for a suitable base of ARG, as below. */
21507 }
21508 }
21509 /* ARG must be constructed from a template class or a template
21510 template parameter. */
21515 /* Deduce arguments T, i from TT<T> or TT<i>. */
21521 /* Fall through to deduce template name. */
21522 }
21526 {
21527 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21529 /* Simple cases: Value already set, does match or doesn't. */
21534 }
21535 else
21536 {
21537 /* If PARM is `const T' and ARG is only `int', we don't have
21538 a match unless we are allowing additional qualification.
21539 If ARG is `const int' and PARM is just `T' that's OK;
21540 that binds `const int' to `T'. */
21545 /* Consider the case where ARG is `const volatile int' and
21546 PARM is `const T'. Then, T should be `volatile int'. */
21547 arg = cp_build_qualified_type_real
21552 /* Simple cases: Value already set, does match or doesn't. */
21558 /* Make sure that ARG is not a variable-sized array. (Note
21559 that were talking about variable-sized arrays (like
21560 `int[n]'), rather than arrays of unknown size (like
21561 `int[]').) We'll get very confused by such a type since
21562 the bound of the array is not constant, and therefore
21563 not mangleable. Besides, such types are not allowed in
21564 ISO C++, so we can do as we please here. We do allow
21565 them for 'auto' deduction, since that isn't ABI-exposed. */
21569 /* Strip typedefs as in convert_template_argument. */
21571 }
21573 /* If ARG is a parameter pack or an expansion, we cannot unify
21574 against it unless PARM is also a parameter pack. */
21579 /* If the argument deduction results is a METHOD_TYPE,
21580 then there is a problem.
21581 METHOD_TYPE doesn't map to any real C++ type the result of
21582 the deduction can not be of that type. */
21596 {
21597 /* The PARM is not one we're trying to unify. Just check
21598 to see if it matches ARG. */
21604 }
21610 {
21614 /* We're deducing from an array bound, the type doesn't matter. */
21620 }
21622 /* [temp.deduct.type] If, in the declaration of a function template
21623 with a non-type template-parameter, the non-type
21624 template-parameter is used in an expression in the function
21625 parameter-list and, if the corresponding template-argument is
21626 deduced, the template-argument type shall match the type of the
21627 template-parameter exactly, except that a template-argument
21628 deduced from an array bound may be of any integral type.
21629 The non-type parameter might use already deduced type parameters. */
21632 /* We don't have enough levels of args to do any substitution. This
21634 else
21635 {
21641 {
21645 }
21646 }
21649 /* Template-parameter dependent expression. Just accept it for now.
21650 It will later be processed in convert_template_argument. */
21651 ;
21657 /* Convert the ARG to the type of PARM; the deduced non-type
21658 template argument must exactly match the types of the
21659 corresponding parameter. */
21662 {
21663 /* We haven't deduced the type of this parameter yet. */
21665 /* We deduce from array bounds in try_array_deduction. */
21667 {
21668 /* Deduce it from the non-type argument. */
21673 }
21674 else
21675 /* Try again later. */
21677 }
21678 else
21681 /* If ARG is a parameter pack or an expansion, we cannot unify
21682 against it unless PARM is also a parameter pack. */
21687 {
21690 }
21695 {
21696 /* A pointer-to-member constant can be unified only with
21697 another constant. */
21701 /* Just unify the class member. It would be useless (and possibly
21702 wrong, depending on the strict flags) to unify also
21703 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21704 arg refer to the same variable, even if through different
21705 classes. For instance:
21707 struct A { int x; };
21708 struct B : A { };
21710 Unification of &A::x and &B::x must succeed. */
21713 }
21716 {
21720 /* [temp.deduct.call]
21722 A can be another pointer or pointer to member type that can
21723 be converted to the deduced A via a qualification
21724 conversion (_conv.qual_).
21726 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21727 This will allow for additional cv-qualification of the
21728 pointed-to types if appropriate. */
21731 /* The derived-to-base conversion only persists through one
21732 level of pointers. */
21737 }
21769 /* We have already checked cv-qualification at the top of the
21770 function. */
21774 /* As far as unification is concerned, this wins. Later checks
21775 will invalidate it if necessary. */
21778 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21779 /* Type INTEGER_CST can come from ordinary constant template args. */
21791 {
21801 /* Check for pack expansions in the parameters. */
21803 {
21805 {
21807 /* We can unify against something with a trailing
21808 parameter pack. */
21810 else
21811 /* [temp.deduct.type]/9: If the template argument list of
21812 P contains a pack expansion that is not the last
21813 template argument, the entire template argument list
21814 is a non-deduced context. */
21816 }
21817 }
21819 /* If we don't have enough arguments to satisfy the parameters
21820 (not counting the pack expression at the end), or we have
21821 too many arguments for a parameter list that doesn't end in
21822 a pack expression, we can't unify. */
21828 /* Unify all of the parameters that precede the (optional)
21829 pack expression. */
21831 {
21836 }
21839 DEDUCE_EXACT,
21842 }
21850 {
21858 }
21863 {
21867 {
21868 /* First, we try to unify the PARM and ARG directly. */
21873 {
21874 /* Fallback to the special case allowed in
21875 [temp.deduct.call]:
21877 If P is a class, and P has the form
21878 template-id, then A can be a derived class of
21879 the deduced A. Likewise, if P is a pointer to
21880 a class of the form template-id, A can be a
21881 pointer to a derived class pointed to by the
21882 deduced A. */
21888 {
21889 /* Don't give the derived diagnostic if we're
21890 already dealing with the same template. */
21891 bool same_template
21897 }
21898 }
21899 }
21903 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21904 Then, we should unify `int' and `U'. */
21906 else
21907 /* There's no chance of unification succeeding. */
21912 }
21919 {
21922 tree a;
21928 /* CV qualifications for methods can never be deduced, they must
21929 match exactly. We need to check them explicitly here,
21930 because type_unification_real treats them as any other
21931 cv-qualified parameter. */
21933 && (!check_cv_quals_for_unify
21961 {
21973 }
21976 }
21979 /* Unify a pointer to member with a pointer to member function, which
21980 deduces the type of the member as a function type. */
21982 {
21983 /* Check top-level cv qualifiers */
21991 /* Determine the type of the function we are unifying against. */
21995 }
22014 /* Matched cases are handled by the ARG == PARM test above. */
22018 /* We might get a variable as a non-type template argument in parm if the
22019 corresponding parameter is type-dependent. Make any necessary
22020 adjustments based on whether arg is a reference. */
22024 {
22029 }
22030 /* Now use the normal expression code to check whether they match. */
22041 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
22042 or UNDERLYING_TYPE nodes. */
22046 /* Unification fails if we hit an error node. */
22051 {
22061 }
22062 /* FALLTHRU */
22065 /* An unresolved overload is a nondeduced context. */
22069 expr:
22070 /* We must be looking at an expression. This can happen with
22071 something like:
22073 template <int I>
22074 void foo(S<I>, S<I + 2>);
22076 This is a "nondeduced context":
22078 [deduct.type]
22080 The nondeduced contexts are:
22082 --A type that is a template-id in which one or more of
22083 the template-arguments is an expression that references
22084 a template-parameter.
22086 In these cases, we assume deduction succeeded, but don't
22087 actually infer any unifications. */
22092 else
22094 }
22095 }
22096 #undef RECUR_AND_CHECK_FAILURE
22097 \f
22098 /* Note that DECL can be defined in this translation unit, if
22099 required. */
22101 static void
22103 {
22104 tree clone;
22108 }
22110 /* Called if RESULT is explicitly instantiated, or is a member of an
22111 explicitly instantiated class. */
22113 void
22115 {
22118 /* If this entity has already been written out, it's too late to
22119 make any modifications. */
22123 /* For anonymous namespace we don't need to do anything. */
22125 {
22128 }
22131 /* The TREE_PUBLIC flag for function declarations will have been
22132 set correctly by tsubst. */
22135 /* This might have been set by an earlier implicit instantiation. */
22140 else
22141 {
22144 /* Always make artificials weak. */
22147 /* For WIN32 we also want to put explicit instantiations in
22148 linkonce sections. */
22151 }
22153 /* If EXTERN_P, then this function will not be emitted -- unless
22154 followed by an explicit instantiation, at which point its linkage
22155 will be adjusted. If !EXTERN_P, then this function will be
22156 emitted here. In neither circumstance do we want
22157 import_export_decl to adjust the linkage. */
22159 }
22161 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
22162 important template arguments. If any are missing, we check whether
22163 they're important by using error_mark_node for substituting into any
22164 args that were used for partial ordering (the ones between ARGS and END)
22165 and seeing if it bubbles up. */
22167 static bool
22169 {
22174 {
22177 }
22179 {
22183 }
22185 }
22187 /* Given two function templates PAT1 and PAT2, return:
22189 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
22190 -1 if PAT2 is more specialized than PAT1.
22191 0 if neither is more specialized.
22193 LEN indicates the number of parameters we should consider
22194 (defaulted parameters should not be considered).
22196 The 1998 std underspecified function template partial ordering, and
22197 DR214 addresses the issue. We take pairs of arguments, one from
22198 each of the templates, and deduce them against each other. One of
22199 the templates will be more specialized if all the *other*
22200 template's arguments deduce against its arguments and at least one
22201 of its arguments *does* *not* deduce against the other template's
22202 corresponding argument. Deduction is done as for class templates.
22203 The arguments used in deduction have reference and top level cv
22204 qualifiers removed. Iff both arguments were originally reference
22205 types *and* deduction succeeds in both directions, an lvalue reference
22206 wins against an rvalue reference and otherwise the template
22207 with the more cv-qualified argument wins for that pairing (if
22208 neither is more cv-qualified, they both are equal). Unlike regular
22209 deduction, after all the arguments have been deduced in this way,
22210 we do *not* verify the deduced template argument values can be
22211 substituted into non-deduced contexts.
22213 The logic can be a bit confusing here, because we look at deduce1 and
22214 targs1 to see if pat2 is at least as specialized, and vice versa; if we
22215 can find template arguments for pat1 to make arg1 look like arg2, that
22216 means that arg2 is at least as specialized as arg1. */
22218 int
22220 {
22233 /* Remove the this parameter from non-static member functions. If
22234 one is a non-static member function and the other is not a static
22235 member function, remove the first parameter from that function
22236 also. This situation occurs for operator functions where we
22237 locate both a member function (with this pointer) and non-member
22238 operator (with explicit first operand). */
22240 {
22245 }
22247 {
22250 {
22251 len--;
22253 }
22254 }
22256 /* If only one is a conversion operator, they are unordered. */
22260 /* Consider the return type for a conversion function */
22262 {
22265 len++;
22266 }
22268 processing_template_decl++;
22274 /* Stop when an ellipsis is seen. */
22276 {
22287 {
22288 /* When both arguments are pack expansions, we need only
22289 unify the patterns themselves. */
22293 /* This is the last comparison we need to do. */
22295 }
22297 /* DR 1847: If a particular P contains no template-parameters that
22298 participate in template argument deduction, that P is not used to
22299 determine the ordering. */
22305 {
22309 }
22312 {
22316 }
22322 {
22328 /* Setup the parameter vector, which contains only ARG1. */
22331 /* Setup the argument vector, which contains the remaining
22332 arguments. */
22341 /* We cannot deduce in the other direction, because ARG1 is
22342 a pack expansion but ARG2 is not. */
22344 }
22346 {
22352 /* Setup the parameter vector, which contains only ARG1. */
22355 /* Setup the argument vector, which contains the remaining
22356 arguments. */
22365 /* We cannot deduce in the other direction, because ARG2 is
22366 a pack expansion but ARG1 is not.*/
22368 }
22370 else
22371 {
22372 /* The normal case, where neither argument is a pack
22373 expansion. */
22380 }
22382 /* If we couldn't deduce arguments for tparms1 to make arg1 match
22383 arg2, then arg2 is not as specialized as arg1. */
22389 /* "If, for a given type, deduction succeeds in both directions
22390 (i.e., the types are identical after the transformations above)
22391 and both P and A were reference types (before being replaced with
22392 the type referred to above):
22393 - if the type from the argument template was an lvalue reference and
22394 the type from the parameter template was not, the argument type is
22395 considered to be more specialized than the other; otherwise,
22396 - if the type from the argument template is more cv-qualified
22397 than the type from the parameter template (as described above),
22398 the argument type is considered to be more specialized than the other;
22399 otherwise,
22400 - neither type is more specialized than the other." */
22403 {
22405 {
22408 else
22410 }
22412 {
22417 }
22418 }
22421 /* We've failed to deduce something in either direction.
22422 These must be unordered. */
22425 next:
22429 /* We have already processed all of the arguments in our
22430 handing of the pack expansion type. */
22435 }
22437 /* "In most cases, all template parameters must have values in order for
22438 deduction to succeed, but for partial ordering purposes a template
22439 parameter may remain without a value provided it is not used in the
22440 types being used for partial ordering."
22442 Thus, if we are missing any of the targs1 we need to substitute into
22443 origs1, then pat2 is not as specialized as pat1. This can happen when
22444 there is a nondeduced context. */
22450 processing_template_decl--;
22452 /* If both deductions succeed, the partial ordering selects the more
22453 constrained template. */
22455 {
22460 }
22462 /* All things being equal, if the next argument is a pack expansion
22463 for one function but not for the other, prefer the
22464 non-variadic function. FIXME this is bogus; see c++/41958. */
22468 {
22471 }
22477 else
22479 }
22481 /* Determine which of two partial specializations of TMPL is more
22482 specialized.
22484 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22485 to the first partial specialization. The TREE_PURPOSE is the
22486 innermost set of template parameters for the partial
22487 specialization. PAT2 is similar, but for the second template.
22489 Return 1 if the first partial specialization is more specialized;
22490 -1 if the second is more specialized; 0 if neither is more
22491 specialized.
22493 See [temp.class.order] for information about determining which of
22494 two templates is more specialized. */
22496 static int
22498 {
22499 tree targs;
22508 /* Just like what happens for functions, if we are ordering between
22509 different template specializations, we may encounter dependent
22510 types in the arguments, and we need our dependency check functions
22511 to behave correctly. */
22515 {
22518 }
22522 {
22525 }
22528 /* If both deductions succeed, the partial ordering selects the more
22529 constrained template. */
22533 /* In the case of a tie where at least one of the templates
22534 has a parameter pack at the end, the template with the most
22535 non-packed parameters wins. */
22537 && any_deductions
22540 {
22546 /* We don't count the pack expansion at the end. */
22556 }
22559 }
22561 /* Return the template arguments that will produce the function signature
22562 DECL from the function template FN, with the explicit template
22563 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22564 also match. Return NULL_TREE if no satisfactory arguments could be
22565 found. */
22567 static tree
22569 {
22573 tree decl_arg_types;
22576 tree arg;
22580 /* Never do unification on the 'this' parameter. */
22601 }
22603 /* Return the innermost template arguments that, when applied to a partial
22604 specialization SPEC_TMPL of TMPL, yield the ARGS.
22606 For example, suppose we have:
22608 template <class T, class U> struct S {};
22609 template <class T> struct S<T*, int> {};
22611 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22612 partial specialization and the ARGS will be {double*, int}. The resulting
22613 vector will be {double}, indicating that `T' is bound to `double'. */
22615 static tree
22617 {
22619 tree spec_args
22622 tree deduced_args;
22623 tree innermost_deduced_args;
22627 {
22631 innermost_deduced_args);
22632 }
22633 else
22637 again:
22646 {
22648 {
22654 }
22656 }
22659 {
22662 }
22664 /* Verify that nondeduced template arguments agree with the type
22665 obtained from argument deduction.
22667 For example:
22669 struct A { typedef int X; };
22670 template <class T, class U> struct C {};
22671 template <class T> struct C<T, typename T::X> {};
22673 Then with the instantiation `C<A, int>', we can deduce that
22674 `T' is `A' but unify () does not check whether `typename T::X'
22675 is `int'. */
22686 /* We only need to check the innermost arguments; the other
22687 arguments will always agree. */
22692 /* Now that we have bindings for all of the template arguments,
22693 ensure that the arguments deduced for the template template
22694 parameters have compatible template parameter lists. See the use
22695 of template_template_parm_bindings_ok_p in fn_type_unification
22696 for more information. */
22701 }
22703 // Compare two function templates T1 and T2 by deducing bindings
22704 // from one against the other. If both deductions succeed, compare
22705 // constraints to see which is more constrained.
22706 static int
22708 {
22713 {
22716 }
22719 {
22722 }
22724 // If both deductions succeed, then one may be more constrained.
22729 }
22731 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22732 Return the TREE_LIST node with the most specialized template, if
22733 any. If there is no most specialized template, the error_mark_node
22734 is returned.
22736 Note that this function does not look at, or modify, the
22737 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22738 returned is one of the elements of INSTANTIATIONS, callers may
22739 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22740 and retrieve it from the value returned. */
22742 tree
22744 {
22751 {
22757 {
22758 /* Equally specialized, move to next function. If there
22759 is no next function, nothing's most specialized. */
22764 }
22765 }
22768 /* Now verify that champ is better than everything earlier in the
22769 instantiation list. */
22772 {
22775 }
22776 }
22778 processing_template_decl--;
22784 }
22786 /* If DECL is a specialization of some template, return the most
22787 general such template. Otherwise, returns NULL_TREE.
22789 For example, given:
22791 template <class T> struct S { template <class U> void f(U); };
22793 if TMPL is `template <class U> void S<int>::f(U)' this will return
22794 the full template. This function will not trace past partial
22795 specializations, however. For example, given in addition:
22797 template <class T> struct S<T*> { template <class U> void f(U); };
22799 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22800 `template <class T> template <class U> S<T*>::f(U)'. */
22802 tree
22804 {
22806 {
22809 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22810 template friend, or a FIELD_DECL for a capture pack. */
22813 }
22815 /* Look for more and more general templates. */
22817 {
22818 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22819 (See cp-tree.h for details.) */
22828 /* Stop if we run into an explicitly specialized class template. */
22835 }
22838 }
22840 /* Return the most specialized of the template partial specializations
22841 which can produce TARGET, a specialization of some class or variable
22842 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22843 a TEMPLATE_DECL node corresponding to the partial specialization, while
22844 the TREE_PURPOSE is the set of template arguments that must be
22845 substituted into the template pattern in order to generate TARGET.
22847 If the choice of partial specialization is ambiguous, a diagnostic
22848 is issued, and the error_mark_node is returned. If there are no
22849 partial specializations matching TARGET, then NULL_TREE is
22850 returned, indicating that the primary template should be used. */
22852 static tree
22854 {
22856 tree t;
22857 tree champ;
22864 {
22868 }
22870 {
22873 }
22875 {
22879 }
22880 else
22885 /* For determining which partial specialization to use, only the
22886 innermost args are interesting. */
22888 {
22891 }
22894 {
22895 tree spec_args;
22899 {
22900 /* Substitute in the template args from the enclosing class. */
22904 }
22911 {
22915 /* Keep the candidate only if the constraints are satisfied,
22916 or if we're not compiling with concepts. */
22919 {
22922 }
22923 }
22924 }
22934 {
22937 ;
22938 else
22939 {
22941 {
22944 {
22947 }
22948 }
22950 }
22951 }
22955 {
22958 {
22961 }
22962 }
22965 {
22972 else
22976 {
22981 }
22984 }
22987 }
22989 /* Explicitly instantiate DECL. */
22991 void
22993 {
22998 /* An error occurred, for which grokdeclarator has already issued
22999 an appropriate message. */
23002 {
23005 }
23011 {
23012 /* There is an asymmetry here in the way VAR_DECLs and
23013 FUNCTION_DECLs are handled by grokdeclarator. In the case of
23014 the latter, the DECL we get back will be marked as a
23015 template instantiation, and the appropriate
23016 DECL_TEMPLATE_INFO will be set up. This does not happen for
23017 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
23018 should handle VAR_DECLs as it currently handles
23019 FUNCTION_DECLs. */
23021 {
23024 }
23027 {
23030 }
23032 {
23037 }
23038 }
23040 {
23043 }
23044 else
23047 /* Check for various error cases. Note that if the explicit
23048 instantiation is valid the RESULT will currently be marked as an
23049 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
23050 until we get here. */
23053 {
23054 /* DR 259 [temp.spec].
23056 Both an explicit instantiation and a declaration of an explicit
23057 specialization shall not appear in a program unless the explicit
23058 instantiation follows a declaration of the explicit specialization.
23060 For a given set of template parameters, if an explicit
23061 instantiation of a template appears after a declaration of an
23062 explicit specialization for that template, the explicit
23063 instantiation has no effect. */
23065 }
23067 {
23068 /* [temp.spec]
23070 No program shall explicitly instantiate any template more
23071 than once.
23073 We check DECL_NOT_REALLY_EXTERN so as not to complain when
23074 the first instantiation was `extern' and the second is not,
23075 and EXTERN_P for the opposite case. */
23078 /* If an "extern" explicit instantiation follows an ordinary
23079 explicit instantiation, the template is instantiated. */
23082 }
23084 {
23087 }
23089 {
23092 }
23095 ;
23097 {
23100 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
23103 }
23104 else
23112 }
23114 static void
23116 {
23122 {
23125 }
23126 }
23128 /* Called from do_type_instantiation through binding_table_foreach to
23129 do recursive instantiation for the type bound in ENTRY. */
23130 static void
23132 {
23139 }
23141 /* Perform an explicit instantiation of template class T. STORAGE, if
23142 non-null, is the RID for extern, inline or static. COMPLAIN is
23143 nonzero if this is called from the parser, zero if called recursively,
23144 since the standard is unclear (as detailed below). */
23146 void
23148 {
23158 {
23159 tree tmpl =
23163 else
23166 }
23171 {
23174 t);
23176 }
23179 {
23181 {
23183 {
23186 "ISO C++ 1998 forbids the use of %<extern%> on "
23188 }
23189 else
23191 "ISO C++ forbids the use of %qE"
23193 }
23201 else
23202 {
23204 storage);
23206 }
23207 }
23210 {
23211 /* DR 259 [temp.spec].
23213 Both an explicit instantiation and a declaration of an explicit
23214 specialization shall not appear in a program unless the explicit
23215 instantiation follows a declaration of the explicit specialization.
23217 For a given set of template parameters, if an explicit
23218 instantiation of a template appears after a declaration of an
23219 explicit specialization for that template, the explicit
23220 instantiation has no effect. */
23222 }
23224 {
23225 /* [temp.spec]
23227 No program shall explicitly instantiate any template more
23228 than once.
23230 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
23231 instantiation was `extern'. If EXTERN_P then the second is.
23232 These cases are OK. */
23239 /* If we've already instantiated the template, just return now. */
23242 }
23250 /* In contrast to implicit instantiation, where only the
23251 declarations, and not the definitions, of members are
23252 instantiated, we have here:
23254 [temp.explicit]
23256 The explicit instantiation of a class template specialization
23257 implies the instantiation of all of its members not
23258 previously explicitly specialized in the translation unit
23259 containing the explicit instantiation.
23261 Of course, we can't instantiate member template classes, since we
23262 don't have any arguments for them. Note that the standard is
23263 unclear on whether the instantiation of the members are
23264 *explicit* instantiations or not. However, the most natural
23265 interpretation is that it should be an explicit
23266 instantiation. */
23270 && !static_p
23273 {
23278 }
23283 }
23285 /* Given a function DECL, which is a specialization of TMPL, modify
23286 DECL to be a re-instantiation of TMPL with the same template
23287 arguments. TMPL should be the template into which tsubst'ing
23288 should occur for DECL, not the most general template.
23290 One reason for doing this is a scenario like this:
23292 template <class T>
23293 void f(const T&, int i);
23295 void g() { f(3, 7); }
23297 template <class T>
23298 void f(const T& t, const int i) { }
23300 Note that when the template is first instantiated, with
23301 instantiate_template, the resulting DECL will have no name for the
23302 first parameter, and the wrong type for the second. So, when we go
23303 to instantiate the DECL, we regenerate it. */
23305 static void
23307 {
23308 /* The arguments used to instantiate DECL, from the most general
23309 template. */
23310 tree code_pattern;
23314 /* Make sure that we can see identifiers, and compute access
23315 correctly. */
23319 {
23320 tree decl_parm;
23321 tree pattern_parm;
23322 tree specs;
23336 specs);
23338 /* Merge parameter declarations. */
23341 pattern_parm
23345 {
23346 tree parm_type;
23347 tree attributes;
23352 NULL_TREE);
23358 {
23361 }
23364 }
23365 /* Merge any parameters that match with the function parameter
23366 pack. */
23368 {
23370 tree expanded_types;
23371 /* Expand the TYPE_PACK_EXPANSION that provides the types for
23372 the parameters in this function parameter pack. */
23377 {
23378 tree parm_type;
23379 tree attributes;
23382 /* Rename the parameter to include the index. */
23391 {
23394 }
23396 }
23397 }
23398 /* Merge additional specifiers from the CODE_PATTERN. */
23402 }
23404 {
23414 }
23415 else
23419 }
23421 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
23422 substituted to get DECL. */
23424 tree
23426 {
23429 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23430 for the instantiation. This is not always the most general
23431 template. Consider, for example:
23433 template <class T>
23434 struct S { template <class U> void f();
23435 template <> void f<int>(); };
23437 and an instantiation of S<double>::f<int>. We want TD to be the
23438 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23440 more general template. */
23442 /* We must also deal with friend templates. Given:
23444 template <class T> struct S {
23445 template <class U> friend void f() {};
23446 };
23448 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23449 so far as the language is concerned, but that's still
23450 where we get the pattern for the instantiation from. On
23451 other hand, if the definition comes outside the class, say:
23453 template <class T> struct S {
23454 template <class U> friend void f();
23455 };
23456 template <class U> friend void f() {}
23458 we don't need to look any further. That's what the check for
23459 DECL_INITIAL is for. */
23463 {
23464 /* The present template, TD, should not be a definition. If it
23465 were a definition, we should be using it! Note that we
23466 cannot restructure the loop to just keep going until we find
23467 a template with a definition, since that might go too far if
23468 a specialization was declared, but not defined. */
23470 /* Fetch the more general template. */
23472 }
23475 }
23477 /* Returns true if we need to instantiate this template instance even if we
23478 know we aren't going to emit it. */
23480 bool
23482 {
23483 /* We always instantiate inline functions so that we can inline them. An
23484 explicit instantiation declaration prohibits implicit instantiation of
23485 non-inline functions. With high levels of optimization, we would
23486 normally inline non-inline functions -- but we're not allowed to do
23487 that for "extern template" functions. Therefore, we check
23488 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23492 /* And we need to instantiate static data members so that
23493 their initializers are available in integral constant
23494 expressions. */
23497 }
23499 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23500 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23501 error, true otherwise. */
23503 bool
23505 {
23508 /* Don't instantiate a noexcept-specification from template context. */
23524 {
23530 {
23531 /* If hash_set::add returns true, the element was already there. */
23536 fn);
23538 }
23540 {
23555 }
23556 else
23566 }
23569 {
23572 else
23574 }
23577 }
23579 /* We're starting to process the function INST, an instantiation of PATTERN;
23580 add their parameters to local_specializations. */
23582 static void
23584 {
23588 {
23592 }
23594 {
23596 {
23599 }
23600 else
23601 {
23602 /* Register the (value) argument pack as a specialization of
23603 TMPL_PARM, then move on. */
23606 }
23607 }
23609 }
23611 /* Produce the definition of D, a _DECL generated from a template. If
23612 DEFER_OK is true, then we don't have to actually do the
23613 instantiation now; we just have to do it sometime. Normally it is
23614 an error if this is an explicit instantiation but D is undefined.
23615 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23616 instantiated class template. */
23618 tree
23620 {
23622 tree gen_args;
23623 tree args;
23624 tree td;
23625 tree code_pattern;
23626 tree spec;
23627 tree gen_tmpl;
23635 /* This function should only be used to instantiate templates for
23636 functions and static member variables. */
23639 /* A concept is never instantiated. */
23642 /* Variables are never deferred; if instantiation is required, they
23643 are instantiated right away. That allows for better code in the
23644 case that an expression refers to the value of the variable --
23645 if the variable has a constant value the referring expression can
23646 take advantage of that fact. */
23650 /* Don't instantiate cloned functions. Instead, instantiate the
23651 functions they cloned. */
23659 /* D has already been instantiated or explicitly specialized, so
23660 there's nothing for us to do here.
23662 It might seem reasonable to check whether or not D is an explicit
23663 instantiation, and, if so, stop here. But when an explicit
23664 instantiation is deferred until the end of the compilation,
23665 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23666 the instantiation. */
23669 /* Check to see whether we know that this template will be
23670 instantiated in some other file, as with "extern template"
23671 extension. */
23674 /* In general, we do not instantiate such templates. */
23682 /* We should already have the extra args. */
23685 /* And what's in the hash table should match D. */
23689 /* This needs to happen before any tsubsting. */
23695 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23696 for the instantiation. */
23701 {
23702 /* Look up an explicit specialization, if any. */
23706 {
23709 }
23710 }
23714 /* We should never be trying to instantiate a member of a class
23715 template or partial specialization. */
23720 /* In the case of a friend template whose definition is provided
23721 outside the class, we may have too many arguments. Drop the
23722 ones we don't need. The same is true for specializations. */
23723 args = get_innermost_template_args
23727 {
23733 }
23734 else
23735 {
23740 else
23742 }
23744 /* We may be in the middle of deferred access check. Disable it now. */
23747 /* Unless an explicit instantiation directive has already determined
23748 the linkage of D, remember that a definition is available for
23749 this entity. */
23759 /* If D is a member of an explicitly instantiated class template,
23760 and no definition is available, treat it like an implicit
23761 instantiation. */
23764 {
23765 /* Leave linkage flags alone on instantiations with anonymous
23766 visibility. */
23768 {
23771 }
23773 }
23775 /* Defer all other templates, unless we have been explicitly
23776 forbidden from doing so. */
23778 template. */
23779 ! pattern_defined
23780 /* If it's OK to postpone instantiation, do so. */
23781 || defer_ok
23782 /* If this is a static data member that will be defined
23783 elsewhere, we don't want to instantiate the entire data
23784 member, but we do want to instantiate the initializer so that
23785 we can substitute that elsewhere. */
23787 /* Handle here a deleted function too, avoid generating
23788 its body (c++/61080). */
23790 {
23791 /* The definition of the static data member is now required so
23792 we must substitute the initializer. */
23796 {
23797 tree ns;
23798 tree init;
23807 args,
23810 /* If instantiating the initializer involved instantiating this
23811 again, don't call cp_finish_decl twice. */
23813 {
23814 /* Make sure the initializer is still constant, in case of
23815 circular dependency (template/instantiate6.C). */
23816 const_init
23820 LOOKUP_ONLYCONVERTING);
23821 }
23825 }
23827 /* We restore the source position here because it's used by
23828 add_pending_template. */
23834 /* [temp.explicit]
23836 The definition of a non-exported function template, a
23837 non-exported member function template, or a non-exported
23838 member function or static data member of a class template
23839 shall be present in every translation unit in which it is
23840 explicitly instantiated. */
23844 /* If we're in unevaluated context, we just wanted to get the
23845 constant value; this isn't an odr use, so don't queue
23846 a full instantiation. */
23849 /* ??? Historically, we have instantiated inline functions, even
23850 when marked as "extern template". */
23854 }
23855 /* Tell the repository that D is available in this translation unit
23856 -- and see if it is supposed to be instantiated here. */
23858 {
23859 /* In a PCH file, despite the fact that the repository hasn't
23860 requested instantiation in the PCH it is still possible that
23861 an instantiation will be required in a file that includes the
23862 PCH. */
23865 /* Instantiate inline functions so that the inliner can do its
23866 job, even though we'll not be emitting a copy of this
23867 function. */
23870 }
23873 tree fn_context;
23876 /* tsubst_lambda_expr resolved any references to enclosing functions. */
23887 else
23888 {
23892 }
23894 /* Mark D as instantiated so that recursive calls to
23895 instantiate_decl do not try to instantiate it again. */
23898 /* Regenerate the declaration in case the template has been modified
23899 by a subsequent redeclaration. */
23902 /* We already set the file and line above. Reset them now in case
23903 they changed as a result of calling regenerate_decl_from_template. */
23907 {
23908 tree init;
23911 /* Clear out DECL_RTL; whatever was there before may not be right
23912 since we've reset the type of the declaration. */
23916 /* The initializer is placed in DECL_INITIAL by
23917 regenerate_decl_from_template so we don't need to
23918 push/pop_access_scope again here. Pull it out so that
23919 cp_finish_decl can process it. */
23924 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23925 initializer. That function will defer actual emission until
23926 we have a chance to determine linkage. */
23929 /* Enter the scope of D so that access-checking works correctly. */
23942 }
23946 {
23947 /* Set up the list of local specializations. */
23951 /* Set up context. */
23955 else
23958 /* Some typedefs referenced from within the template code need to be
23959 access checked at template instantiation time, i.e now. These
23960 types were added to the template at parsing time. Let's get those
23961 and perform the access checks then. */
23963 args);
23965 /* Create substitution entries for the parameters. */
23968 /* Substitute into the body of the function. */
23972 else
23973 {
23978 /* Set the current input_location to the end of the function
23979 so that finish_function knows where we are. */
23980 input_location
23983 /* Remember if we saw an infinite loop in the template. */
23984 current_function_infinite_loop
23986 }
23988 /* Finish the function. */
23992 else
23993 {
23996 }
24000 }
24002 /* We're not deferring instantiation any more. */
24007 else
24013 out:
24022 }
24024 /* Run through the list of templates that we wish we could
24025 instantiate, and instantiate any we can. RETRIES is the
24026 number of times we retry pending template instantiation. */
24028 void
24030 {
24034 /* Instantiating templates may trigger vtable generation. This in turn
24035 may require further template instantiations. We place a limit here
24036 to avoid infinite loop. */
24038 {
24042 "template instantiation depth exceeds maximum of %d"
24043 " instantiating %q+D, possibly from virtual table generation"
24047 /* Pretend that we defined it. */
24050 }
24052 do
24053 {
24058 {
24063 {
24065 {
24080 }
24083 }
24084 else
24085 {
24088 {
24089 instantiation
24095 }
24099 }
24102 {
24103 /* If INSTANTIATION has been instantiated, then we don't
24104 need to consider it again in the future. */
24109 }
24110 else
24111 {
24114 }
24117 }
24119 }
24123 }
24125 /* Substitute ARGVEC into T, which is a list of initializers for
24126 either base class or a non-static data member. The TREE_PURPOSEs
24127 are DECLs, and the TREE_VALUEs are the initializer values. Used by
24128 instantiate_decl. */
24130 static tree
24132 {
24137 {
24138 tree decl;
24139 tree init;
24145 {
24146 tree expr;
24147 tree arg;
24149 /* Expand the base class expansion type into separate base
24150 classes. */
24152 tf_warning_or_error,
24153 NULL_TREE);
24157 /* We'll be building separate TREE_LISTs of arguments for
24158 each base. */
24164 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
24165 expand each argument in the TREE_VALUE of t. */
24172 /* VOID_TYPE_NODE is used to indicate
24173 value-initialization. */
24174 {
24177 }
24178 else
24179 {
24180 /* Substitute parameter packs into each argument in the
24181 TREE_LIST. */
24184 {
24185 tree expanded_exprs;
24187 /* Expand the argument. */
24189 expanded_exprs
24191 tf_warning_or_error,
24192 NULL_TREE);
24196 /* Prepend each of the expanded expressions to the
24197 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
24199 {
24204 }
24205 }
24208 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
24209 since we built them backwards. */
24211 {
24214 }
24215 }
24216 }
24219 {
24221 {
24225 }
24226 else
24227 {
24228 tree tmp;
24243 /* If we had an initializer but it instantiated to nothing,
24244 value-initialize the object. This will only occur when
24245 the initializer was a pack expansion where the parameter
24246 packs used in that expansion were of length zero. */
24249 }
24253 {
24255 decl);
24257 }
24258 /* Look for a target constructor. */
24262 {
24265 {
24269 }
24271 }
24274 {
24278 }
24279 }
24280 }
24282 }
24284 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
24286 static void
24288 {
24293 else
24295 }
24297 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
24298 is the instantiation (which should have been created with
24299 start_enum) and ARGS are the template arguments to use. */
24301 static void
24303 {
24304 tree e;
24310 {
24311 tree value;
24312 tree decl;
24315 /* Note that in a template enum, the TREE_VALUE is the
24316 CONST_DECL, not the corresponding INTEGER_CST. */
24321 /* Give this enumeration constant the correct access. */
24324 /* Actually build the enumerator itself. Here we're assuming that
24325 enumerators can't have dependent attributes. */
24328 }
24338 }
24340 /* DECL is a FUNCTION_DECL that is a template specialization. Return
24341 its type -- but without substituting the innermost set of template
24342 arguments. So, innermost set of template parameters will appear in
24343 the type. */
24345 tree
24347 {
24348 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
24350 }
24352 /* Return truthvalue if we're processing a template different from
24353 the last one involved in diagnostics. */
24354 bool
24356 {
24358 }
24360 /* Remember current template involved in diagnostics. */
24361 void
24363 {
24365 }
24369 {
24371 }
24373 /* Return TRUE if current_function_decl is being instantiated, false
24374 otherwise. */
24376 bool
24378 {
24382 }
24384 /* [temp.param] Check that template non-type parm TYPE is of an allowable
24385 type. Return false for ok, true for disallowed. Issue error and
24386 inform messages under control of COMPLAIN. */
24388 static bool
24390 {
24408 /* A bound template template parm could later be instantiated to have a valid
24409 nontype parm type via an alias template. */
24415 {
24418 else
24420 type);
24421 }
24423 }
24425 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
24426 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
24428 static bool
24430 {
24431 tree scope;
24433 /* [temp.dep.type]
24435 A type is dependent if it is:
24437 -- a template parameter. Template template parameters are types
24438 for us (since TYPE_P holds true for them) so we handle
24439 them here. */
24443 /* -- a qualified-id with a nested-name-specifier which contains a
24444 class-name that names a dependent type or whose unqualified-id
24445 names a dependent type. */
24449 /* An alias template specialization can be dependent even if the
24450 resulting type is not. */
24454 /* -- a cv-qualified type where the cv-unqualified type is
24455 dependent.
24456 No code is necessary for this bullet; the code below handles
24457 cv-qualified types, and we don't want to strip aliases with
24458 TYPE_MAIN_VARIANT because of DR 1558. */
24459 /* -- a compound type constructed from any dependent type. */
24469 {
24470 tree arg_type;
24475 arg_type;
24480 /* A value-dependent noexcept-specifier makes the type dependent. */
24483 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24484 affect overload resolution and treating it as dependent breaks
24485 things. */
24490 }
24491 /* -- an array type constructed from any dependent type or whose
24492 size is specified by a constant expression that is
24493 value-dependent.
24495 We checked for type- and value-dependence of the bounds in
24496 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24498 {
24503 }
24505 /* -- a template-id in which either the template name is a template
24506 parameter ... */
24509 /* ... or any of the template arguments is a dependent type or
24510 an expression that is type-dependent or value-dependent. */
24512 && (any_dependent_template_arguments_p
24516 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24517 dependent; if the argument of the `typeof' expression is not
24518 type-dependent, then it should already been have resolved. */
24524 /* A template argument pack is dependent if any of its packed
24525 arguments are. */
24527 {
24533 }
24535 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24536 be template parameters. */
24543 /* The standard does not specifically mention types that are local
24544 to template functions or local classes, but they should be
24545 considered dependent too. For example:
24547 template <int I> void f() {
24548 enum E { a = I };
24549 S<sizeof (E)> s;
24550 }
24552 The size of `E' cannot be known until the value of `I' has been
24553 determined. Therefore, `E' must be considered dependent. */
24557 /* Don't use type_dependent_expression_p here, as it can lead
24558 to infinite recursion trying to determine whether a lambda
24559 nested in a lambda is dependent (c++/47687). */
24563 && (any_dependent_template_arguments_p
24567 /* Other types are non-dependent. */
24569 }
24571 /* Returns TRUE if TYPE is dependent, in the sense of
24572 [temp.dep.type]. Note that a NULL type is considered dependent. */
24574 bool
24576 {
24577 /* If there are no template parameters in scope, then there can't be
24578 any dependent types. */
24580 {
24581 /* If we are not processing a template, then nobody should be
24582 providing us with a dependent type. */
24586 }
24588 /* If the type is NULL, we have not computed a type for the entity
24589 in question; in that case, the type is dependent. */
24593 /* Erroneous types can be considered non-dependent. */
24597 /* Getting here with global_type_node means we improperly called this
24598 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24601 /* If we have not already computed the appropriate value for TYPE,
24602 do so now. */
24604 {
24607 }
24610 }
24612 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24613 lookup. In other words, a dependent type that is not the current
24614 instantiation. */
24616 bool
24618 {
24621 }
24623 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24624 an unknown base of 'this' (and is therefore instantiation-dependent). */
24626 static bool
24628 {
24645 }
24647 /* T is a SCOPE_REF; return whether we need to consider it
24648 instantiation-dependent so that we can check access at instantiation
24649 time even though we know which member it resolves to. */
24651 static bool
24653 {
24660 else
24662 }
24664 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24665 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24666 expression. */
24668 /* Note that this predicate is not appropriate for general expressions;
24669 only constant expressions (that satisfy potential_constant_expression)
24670 can be tested for value dependence. */
24672 bool
24674 {
24678 /* A type-dependent expression is also value-dependent. */
24683 {
24685 /* A dependent member function of the current instantiation. */
24689 /* A dependent member function of the current instantiation. */
24696 /* A name that has not been looked up -- must be dependent. */
24700 /* A non-type template parm. */
24704 /* A non-type template parm. */
24710 /* A constant with literal type and is initialized
24711 with an expression that is value-dependent. */
24713 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24717 {
24721 }
24730 /* These expressions are value-dependent if the type to which
24731 the cast occurs is dependent or the expression being casted
24732 is value-dependent. */
24733 {
24739 /* A functional cast has a list of operands. */
24742 {
24743 /* If there are no operands, it must be an expression such
24744 as "int()". This should not happen for aggregate types
24745 because it would form non-constant expressions. */
24750 }
24756 }
24761 /* FALLTHRU */
24764 /* A `sizeof' expression is value-dependent if the operand is
24765 type-dependent or is a pack expansion. */
24774 /* An 'encode' expression is value-dependent if the operand is
24775 type-dependent. */
24784 /* All instantiation-dependent expressions should also be considered
24785 value-dependent. */
24793 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24794 is value-dependent. */
24795 {
24804 }
24807 {
24824 }
24835 {
24839 }
24842 /* Treat all requires-expressions as value-dependent so
24843 we don't try to fold them. */
24850 {
24857 {
24859 /* In a call to a constexpr member function, look through the
24860 implicit ADDR_EXPR on the object argument so that it doesn't
24861 cause the call to be considered value-dependent. We also
24862 look through it in potential_constant_expression. */
24869 }
24871 }
24877 {
24879 tree val;
24886 }
24889 /* Treat a GNU statement expression as dependent to avoid crashing
24890 under instantiate_non_dependent_expr; it can't be constant. */
24894 /* A constant expression is value-dependent if any subexpression is
24895 value-dependent. */
24897 {
24904 {
24908 {
24911 /* In some cases, some of the operands may be missing.
24912 (For example, in the case of PREDECREMENT_EXPR, the
24913 amount to increment by may be missing.) That doesn't
24914 make the expression dependent. */
24917 }
24918 }
24922 }
24924 }
24926 /* The expression is not value-dependent. */
24928 }
24930 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24931 [temp.dep.expr]. Note that an expression with no type is
24932 considered dependent. Other parts of the compiler arrange for an
24933 expression with type-dependent subexpressions to have no type, so
24934 this function doesn't have to be fully recursive. */
24936 bool
24938 {
24947 /* An unresolved name is always dependent. */
24953 /* A fold expression is type-dependent. */
24960 /* Some expression forms are never type-dependent. */
24974 /* The types of these expressions depends only on the type to which
24975 the cast occurs. */
24984 /* The types of these expressions depends only on the type created
24985 by the expression. */
24988 {
24989 /* For NEW_EXPR tree nodes created inside a template, either
24990 the object type itself or a TREE_LIST may appear as the
24991 operand 1. */
24994 /* This is an array type. We need to check array dimensions
24995 as well. */
24997 || value_dependent_expression_p
24999 else
25001 }
25004 {
25008 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
25009 contains an identifier associated by name lookup with one or more
25010 declarations declared with a dependent type, or...a
25011 nested-name-specifier or qualified-id that names a member of an
25012 unknown specialization. */
25015 }
25025 {
25026 tree elt;
25030 {
25033 }
25035 }
25037 /* A static data member of the current instantiation with incomplete
25038 array type is type-dependent, as the definition and specializations
25039 can have different bounds. */
25046 /* An array of unknown bound depending on a variadic parameter, eg:
25048 template<typename... Args>
25049 void foo (Args... args)
25050 {
25051 int arr[] = { args... };
25052 }
25054 template<int... vals>
25055 void bar ()
25056 {
25057 int arr[] = { vals... };
25058 }
25060 If the array has no length and has an initializer, it must be that
25061 we couldn't determine its length in cp_complete_array_type because
25062 it is dependent. */
25070 /* A function or variable template-id is type-dependent if it has any
25071 dependent template arguments. */
25075 {
25076 /* Consider the innermost template arguments, since those are the ones
25077 that come from the template-id; the template arguments for the
25078 enclosing class do not make it type-dependent unless they are used in
25079 the type of the decl. */
25081 && (any_dependent_template_arguments_p
25084 }
25086 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
25087 type-dependent. Checking this is important for functions with auto return
25088 type, which looks like a dependent type. */
25097 {
25101 }
25103 /* Always dependent, on the number of arguments if nothing else. */
25108 {
25113 {
25119 }
25120 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
25125 {
25130 }
25133 {
25140 }
25150 }
25154 /* Dependent type attributes might not have made it from the decl to
25155 the type yet. */
25161 }
25163 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
25164 type-dependent if the expression refers to a member of the current
25165 instantiation and the type of the referenced member is dependent, or the
25166 class member access expression refers to a member of an unknown
25167 specialization.
25169 This function returns true if the OBJECT in such a class member access
25170 expression is of an unknown specialization. */
25172 bool
25174 {
25175 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
25176 dependent. */
25181 }
25183 /* walk_tree callback function for instantiation_dependent_expression_p,
25184 below. Returns non-zero if a dependent subexpression is found. */
25186 static tree
25189 {
25191 {
25192 /* We don't have to worry about decltype currently because decltype
25193 of an instantiation-dependent expr is a dependent type. This
25194 might change depending on the resolution of DR 1172. */
25197 }
25200 {
25201 /* Don't treat an argument list as dependent just because it has no
25202 TREE_TYPE. */
25210 /* Handle expressions with type operands. */
25215 {
25220 {
25223 else
25224 {
25227 }
25228 }
25230 }
25234 /* In a template, finish_class_member_access_expr creates a
25235 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
25236 type-dependent, so that we can check access control at
25237 instantiation time (PR 42277). See also Core issue 1273. */
25244 else
25247 /* Treat statement-expressions as dependent. */
25251 /* Treat requires-expressions as dependent. */
25256 /* Treat calls to function concepts as dependent. */
25262 /* And variable concepts. */
25269 }
25273 else
25275 }
25277 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
25278 sense defined by the ABI:
25280 "An expression is instantiation-dependent if it is type-dependent
25281 or value-dependent, or it has a subexpression that is type-dependent
25282 or value-dependent."
25284 Except don't actually check value-dependence for unevaluated expressions,
25285 because in sizeof(i) we don't care about the value of i. Checking
25286 type-dependence will in turn check value-dependence of array bounds/template
25287 arguments as needed. */
25289 bool
25291 {
25292 tree result;
25303 }
25305 /* As above, but also check value-dependence of the expression as a whole. */
25307 bool
25309 {
25312 }
25314 /* Like type_dependent_expression_p, but it also works while not processing
25315 a template definition, i.e. during substitution or mangling. */
25317 bool
25319 {
25325 }
25327 /* Returns TRUE if ARGS contains a type-dependent expression. */
25329 bool
25331 {
25333 tree arg;
25336 {
25339 }
25341 }
25343 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25344 expressions) contains any type-dependent expressions. */
25346 bool
25348 {
25354 }
25356 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25357 expressions) contains any value-dependent expressions. */
25359 bool
25361 {
25367 }
25369 /* Returns TRUE if the ARG (a template argument) is dependent. */
25371 bool
25373 {
25377 /* Assume a template argument that was wrongly written by the user
25378 is dependent. This is consistent with what
25379 any_dependent_template_arguments_p [that calls this function]
25380 does. */
25390 {
25393 /* A member template of a dependent class is not necessarily
25394 type-dependent, but it is a dependent template argument because it
25395 will be a member of an unknown specialization to that template. */
25398 }
25400 {
25404 {
25407 }
25410 }
25413 else
25416 }
25418 /* Returns true if ARGS (a collection of template arguments) contains
25419 any types that require structural equality testing. */
25421 bool
25423 {
25433 {
25436 {
25442 {
25443 /* Look inside the argument pack. */
25446 }
25449 {
25462 }
25463 }
25464 }
25467 }
25469 /* Returns true if ARGS (a collection of template arguments) contains
25470 any dependent arguments. */
25472 bool
25474 {
25484 {
25489 }
25492 }
25494 /* Returns true if ARGS contains any errors. */
25496 bool
25498 {
25506 {
25509 else
25511 }
25517 {
25522 }
25525 }
25527 /* Returns TRUE if the template TMPL is type-dependent. */
25529 bool
25531 {
25533 {
25538 }
25540 /* Template template parameters are dependent. */
25544 /* So are names that have not been looked up. */
25548 }
25550 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25552 bool
25554 {
25557 }
25559 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25560 are dependent. */
25562 bool
25564 {
25571 {
25593 {
25597 }
25601 {
25605 {
25610 }
25611 }
25612 }
25615 }
25617 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25618 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25619 no such TYPE can be found. Note that this function peers inside
25620 uninstantiated templates and therefore should be used only in
25621 extremely limited situations. ONLY_CURRENT_P restricts this
25622 peering to the currently open classes hierarchy (which is required
25623 when comparing types). */
25625 tree
25627 {
25628 tree scope;
25629 tree name;
25630 tree decl;
25632 tree pushed_scope;
25633 tree result;
25638 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25641 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25642 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25643 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25644 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25645 identifier of the TYPENAME_TYPE anymore.
25646 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25647 TYPENAME_TYPE instead, we avoid messing up with a possible
25648 typedef variant case. */
25651 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25652 it first before we can figure out what NAME refers to. */
25654 {
25656 /* Given a class template A with a dependent base with nested type C,
25657 typedef typename A::C::C C will land us here, as trying to resolve
25658 the initial A::C leads to the local C typedef, which leads back to
25659 A::C::C. So we break the recursion now. */
25661 else
25663 }
25664 /* If we don't know what SCOPE refers to, then we cannot resolve the
25665 TYPENAME_TYPE. */
25668 /* If this is a typedef, we don't want to look inside (c++/11987). */
25671 /* If SCOPE isn't the template itself, it will not have a valid
25672 TYPE_FIELDS list. */
25674 /* scope is either the template itself or a compatible instantiation
25675 like X<T>, so look up the name in the original template. */
25677 /* If scope has no fields, it can't be a current instantiation. Check this
25678 before currently_open_class to avoid infinite recursion (71515). */
25681 /* If the SCOPE is not the current instantiation, there's no reason
25682 to look inside it. */
25685 /* Enter the SCOPE so that name lookup will be resolved as if we
25686 were in the class definition. In particular, SCOPE will no
25687 longer be considered a dependent type. */
25689 /* Look up the declaration. */
25691 tf_warning_or_error);
25695 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25696 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25702 {
25706 }
25709 {
25710 /* Obtain the template and the arguments. */
25713 {
25714 /* We get here with a plain identifier because a previous tentative
25715 parse of the nested-name-specifier as part of a ptr-operator saw
25716 ::template X<A>. The use of ::template is necessary in a
25717 ptr-operator, but wrong in a declarator-id.
25719 [temp.names]: In a qualified-id of a declarator-id, the keyword
25720 template shall not appear at the top level. */
25724 }
25726 /* Instantiate the template. */
25732 }
25734 /* Leave the SCOPE. */
25738 /* If we failed to resolve it, return the original typename. */
25742 /* If lookup found a typename type, resolve that too. */
25744 {
25745 /* Ill-formed programs can cause infinite recursion here, so we
25746 must catch that. */
25750 }
25752 /* Qualify the resulting type. */
25758 }
25760 /* EXPR is an expression which is not type-dependent. Return a proxy
25761 for EXPR that can be used to compute the types of larger
25762 expressions containing EXPR. */
25764 tree
25766 {
25768 tree inner_expr;
25770 /* When checking, try to get a constant value for all non-dependent
25771 expressions in order to expose bugs in *_dependent_expression_p
25772 and constexpr. This can affect code generation, see PR70704, so
25773 only do this for -fchecking=2. */
25776 /* Don't do this during nsdmi parsing as it can lead to
25777 unexpected recursive instantiations. */
25779 /* Don't do this during concept expansion either and for
25780 the same reason. */
25786 /* Preserve OVERLOADs; the functions must be available to resolve
25787 types. */
25798 /* There is no need to return a proxy for a variable. */
25801 /* Preserve string constants; conversions from string constants to
25802 "char *" are allowed, even though normally a "const char *"
25803 cannot be used to initialize a "char *". */
25806 /* Preserve void and arithmetic constants, as an optimization -- there is no
25807 reason to create a new node. */
25812 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25813 There is at least one place where we want to know that a
25814 particular expression is a throw-expression: when checking a ?:
25815 expression, there are special rules if the second or third
25816 argument is a throw-expression. */
25820 /* Don't wrap an initializer list, we need to be able to look inside. */
25824 /* Don't wrap a dummy object, we need to be able to test for it. */
25843 /* If the type is unknown, it can't really be non-dependent */
25846 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25849 }
25851 /* ARGS is a vector of expressions as arguments to a function call.
25852 Replace the arguments with equivalent non-dependent expressions.
25853 This modifies ARGS in place. */
25855 void
25857 {
25859 tree arg;
25862 {
25866 }
25867 }
25869 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25870 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25871 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25873 static tree
25875 {
25889 }
25891 tree
25893 {
25895 }
25897 tree
25899 {
25901 }
25903 /* Return a C++17 deduction placeholder for class template TMPL. */
25905 tree
25907 {
25911 }
25913 /* True iff T is a C++17 class template deduction placeholder. */
25915 bool
25917 {
25919 }
25921 /* Make a "constrained auto" type-specifier. This is an
25922 auto type with constraints that must be associated after
25923 deduction. The constraint is formed from the given
25924 CONC and its optional sequence of arguments, which are
25925 non-null if written as partial-concept-id. */
25927 tree
25929 {
25932 /* Build the constraint. */
25940 /* Our canonical type depends on the constraint. */
25943 /* Attach the constraint to the type declaration. */
25946 }
25948 /* Given type ARG, return std::initializer_list<ARG>. */
25950 static tree
25952 {
25956 {
25960 "deducing from brace-enclosed initializer list"
25964 }
25970 }
25972 /* Replace auto in TYPE with std::initializer_list<auto>. */
25974 static tree
25976 {
25983 }
25985 /* Hash traits for hashing possibly constrained 'auto'
25986 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25989 {
25992 };
25994 /* Hash the 'auto' T. */
25996 inline hashval_t
25998 {
26000 /* Matching constrained-type-specifiers denote the same template
26001 parameter, so hash the constraint. */
26003 else
26004 /* But unconstrained autos are all separate, so just hash the pointer. */
26006 }
26008 /* Compare two 'auto's. */
26012 {
26019 /* Two unconstrained autos are distinct. */
26024 }
26026 /* for_each_template_parm callback for extract_autos: if t is a (possibly
26027 constrained) auto, add it to the vector. */
26029 static int
26031 {
26034 {
26035 /* All the autos were built with index 0; fix that up now. */
26039 /* If this is a repeated constrained-type-specifier, use the index we
26040 chose before. */
26042 else
26043 {
26044 /* Otherwise this is new, so use the current count. */
26047 }
26049 }
26051 /* Always keep walking. */
26053 }
26055 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
26056 says they can appear anywhere in the type. */
26058 static tree
26060 {
26069 {
26074 }
26077 }
26079 /* The stem for deduction guide names. */
26082 /* Return the name for a deduction guide for class template TMPL. */
26084 tree
26086 {
26097 }
26099 /* True if NAME is the name of a deduction guide. */
26101 bool
26103 {
26108 }
26110 /* True if FN is a deduction guide. */
26112 bool
26114 {
26119 }
26121 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
26123 bool
26125 {
26132 }
26134 /* True if FN is a guide generated from a constructor template. */
26136 bool
26138 {
26146 }
26148 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
26149 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
26150 template parameter types. Note that the handling of template template
26151 parameters relies on current_template_parms being set appropriately for the
26152 new template. */
26154 static tree
26157 {
26163 tree newtype;
26166 {
26173 }
26174 else
26175 {
26178 {
26179 // Substitute once to fix references to other template parameters.
26182 // Now substitute again to reduce the level of the auto.
26185 }
26186 else
26189 }
26191 tree newdecl
26196 tree newidx;
26199 {
26209 {
26214 // First create a copy (ttargs) of tsubst_args with an
26215 // additional level for the template template parameter's own
26216 // template parameters (ttparms).
26217 tree ttparms = (INNERMOST_TEMPLATE_PARMS
26225 // Substitute ttargs into ttparms to fix references to
26226 // other template parameters.
26229 // Now substitute again with args based on tparms, to reduce
26230 // the level of the ttparms.
26233 complain);
26234 // Finally, tack the adjusted parms onto tparms.
26236 current_template_parms);
26238 }
26239 }
26240 else
26241 {
26243 tree newconst
26255 }
26258 }
26260 /* Returns a C++17 class deduction guide template based on the constructor
26261 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
26262 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
26264 static tree
26266 {
26270 location_t loc;
26274 {
26278 {
26281 }
26282 else
26292 }
26293 else
26294 {
26298 fn_tmpl
26308 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
26309 fully specialized args for the enclosing class. Strip those off, as
26310 the deduction guide won't have those template parameters. */
26313 /* Discard the 'this' parameter. */
26321 {
26324 /* For a member template constructor, we need to flatten the two
26325 template parameter lists into one, and then adjust the function
26326 signature accordingly. This gets...complicated. */
26329 /* For a member template we should have two levels of parms/args, one
26330 for the class and one for the constructor. We stripped
26331 specialized args for further enclosing classes above. */
26335 /* Template args for translating references to the two-level template
26336 parameters into references to the one-level template parameters we
26337 are creating. */
26342 /* Template parms for the constructor template. */
26345 /* Template parms for the class template. */
26349 /* Template parms for the deduction guide start as a copy of the
26350 template parms for the class. We set current_template_parms for
26351 lookup_template_class_1. */
26357 /* Now we need to rewrite the constructor parms to append them to the
26358 class parms. */
26360 {
26377 }
26379 /* Now we have a final set of template parms to substitute into the
26380 function signature. */
26389 }
26394 }
26397 {
26398 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
26402 }
26406 FUNCTION_DECL,
26423 }
26425 /* Deduce template arguments for the class template placeholder PTYPE for
26426 template TMPL based on the initializer INIT, and return the resulting
26427 type. */
26429 static tree
26431 tsubst_flags_t complain)
26432 {
26434 {
26435 /* We should have handled this in the caller. */
26441 }
26452 {
26455 {
26456 /* As an exception, the first phase in 16.3.1.7 (considering the
26457 initializer list as a single argument) is omitted if the
26458 initializer list consists of a single expression of type cv U,
26459 where U is a specialization of C or a class derived from a
26460 specialization of C. */
26471 }
26474 else
26476 }
26477 else
26488 /* Prune explicit deduction guides in copy-initialization context. */
26490 {
26496 {
26497 /* Found a nonconverting guide, prune the candidates. */
26504 }
26505 }
26510 {
26513 }
26516 // FIXME cache artificial deduction guides
26518 {
26519 /* Skip inherited constructors. */
26529 else
26533 }
26537 /* If this is list-initialization and the class has a list constructor, first
26538 try deducing from the list as a single argument, as [over.match.list]. */
26542 {
26546 }
26548 {
26554 {
26555 /* That didn't work, now try treating the list as a sequence of
26556 arguments. */
26559 }
26560 }
26562 /* Maybe generate an implicit deduction guide. */
26564 {
26568 /* Generate a copy guide. */
26571 /* Generate a default guide. */
26575 {
26580 }
26581 }
26584 {
26586 " of %qT, as it has no non-explicit deduction guides or "
26589 }
26591 {
26595 }
26598 {
26602 }
26605 {
26615 }
26620 }
26622 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26623 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26624 The CONTEXT determines the context in which auto deduction is performed
26625 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26626 OUTER_TARGS are used during template argument deduction
26627 (context == adc_unify) to properly substitute the result, and is ignored
26628 in other contexts.
26630 For partial-concept-ids, extra args may be appended to the list of deduced
26631 template arguments prior to determining constraint satisfaction. */
26633 tree
26637 {
26638 tree targs;
26645 /* Defining a subset of type-dependent expressions that we can deduce
26646 from ahead of time isn't worth the trouble. */
26649 /* Similarly, we can't deduce from another undeduced decl. */
26654 /* C++17 class template argument deduction. */
26658 /* Nothing we can do with this, even in deduction context. */
26661 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26662 with either a new invented type template parameter U or, if the
26663 initializer is a braced-init-list (8.5.4), with
26664 std::initializer_list<U>. */
26666 {
26671 else
26672 {
26674 {
26678 "for deduction to %<std::initializer_list%>, use copy-"
26680 }
26682 }
26683 }
26694 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26695 and initializer has array type, deduce cv-qualified array type. */
26697 complain);
26699 {
26708 {
26712 }
26713 }
26714 else
26715 {
26717 tree tparms;
26721 else
26722 {
26726 }
26733 {
26735 /* Try again at instantiation time. */
26739 /* If type is error_mark_node a diagnostic must have been
26740 emitted by now. Also, having a mention to '<type error>'
26741 in the diagnostic is not really useful to the user. */
26742 {
26746 else
26751 }
26753 }
26754 }
26756 /* Check any placeholder constraints against the deduced type. */
26759 {
26760 /* Use the deduced type to check the associated constraints. If we
26761 have a partial-concept-id, rebuild the argument list so that
26762 we check using the extra arguments. */
26766 {
26769 }
26770 else
26773 {
26775 {
26777 {
26795 }
26797 }
26799 }
26800 }
26806 }
26808 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26809 result. */
26811 tree
26813 {
26815 {
26821 /* In an abbreviated function template we didn't know we were dealing
26822 with a function template when we saw the auto return type, so update
26823 it to have the correct level. */
26825 }
26827 }
26829 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26830 'decltype(auto)' or a deduced class template. */
26832 bool
26834 {
26840 else
26842 }
26844 /* for_each_template_parm callback for type_uses_auto. */
26846 int
26848 {
26850 }
26852 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26853 a use of `auto'. Returns NULL_TREE otherwise. */
26855 tree
26857 {
26861 {
26862 /* The Concepts TS allows multiple autos in one type-specifier; just
26863 return the first one we find, do_auto_deduction will collect all of
26864 them. */
26868 else
26870 }
26871 else
26873 }
26875 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
26876 concepts are enabled, auto is acceptable in template arguments, but
26877 only when TEMPL identifies a template class. Return TRUE if any
26878 such errors were reported. */
26880 bool
26882 {
26883 /* If there were previous errors, nevermind. */
26887 /* If TMPL is an identifier, we're parsing and we can't tell yet
26888 whether TMPL is supposed to be a type, a function or a variable.
26889 We'll only be able to tell during template substitution, so we
26890 expect to be called again then. If concepts are enabled and we
26891 know we have a type, we're ok. */
26899 /* Quickly search for any occurrences of auto; usually there won't
26900 be any, and then we'll avoid allocating the vector. */
26908 {
26913 }
26916 }
26918 /* For a given template T, return the vector of typedefs referenced
26919 in T for which access check is needed at T instantiation time.
26920 T is either a FUNCTION_DECL or a RECORD_TYPE.
26921 Those typedefs were added to T by the function
26922 append_type_to_template_for_access_check. */
26926 {
26927 tree ti;
26938 {
26943 }
26946 }
26948 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26949 tied to T. That list of typedefs will be access checked at
26950 T instantiation time.
26951 T is either a FUNCTION_DECL or a RECORD_TYPE.
26952 TYPE_DECL is a TYPE_DECL node representing a typedef.
26953 SCOPE is the scope through which TYPE_DECL is accessed.
26954 LOCATION is the location of the usage point of TYPE_DECL.
26956 This function is a subroutine of
26957 append_type_to_template_for_access_check. */
26959 static void
26961 tree type_decl,
26962 tree scope,
26963 location_t location)
26964 {
26965 qualified_typedef_usage_t typedef_usage;
26966 tree ti;
26973 && type_decl
26987 }
26989 /* Append TYPE_DECL to the template TEMPL.
26990 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26991 At TEMPL instanciation time, TYPE_DECL will be checked to see
26992 if it can be accessed through SCOPE.
26993 LOCATION is the location of the usage point of TYPE_DECL.
26995 e.g. consider the following code snippet:
26997 class C
26998 {
26999 typedef int myint;
27000 };
27002 template<class U> struct S
27003 {
27004 C::myint mi; // <-- usage point of the typedef C::myint
27005 };
27007 S<char> s;
27009 At S<char> instantiation time, we need to check the access of C::myint
27010 In other words, we need to check the access of the myint typedef through
27011 the C scope. For that purpose, this function will add the myint typedef
27012 and the scope C through which its being accessed to a list of typedefs
27013 tied to the template S. That list will be walked at template instantiation
27014 time and access check performed on each typedefs it contains.
27015 Note that this particular code snippet should yield an error because
27016 myint is private to C. */
27018 void
27020 tree type_decl,
27021 tree scope,
27022 location_t location)
27023 {
27029 /* Make sure we don't append the type to the template twice. */
27036 }
27038 /* Convert the generic type parameters in PARM that match the types given in the
27039 range [START_IDX, END_IDX) from the current_template_parms into generic type
27040 packs. */
27042 tree
27044 {
27055 {
27056 /* Create a distinct parameter pack type from the current parm and add it
27057 to the replacement args to tsubst below into the generic function
27058 parameter. */
27073 }
27079 /* If there are more levels then build up the replacement with the outer
27080 template parms. */
27084 replacement);
27087 }
27089 /* Entries in the decl_constraint hash table. */
27091 {
27092 tree decl;
27093 tree ci;
27094 };
27096 /* Hashing function and equality for constraint entries. */
27098 {
27100 {
27102 }
27105 {
27107 }
27108 };
27110 /* A mapping from declarations to constraint information. Note that
27111 both templates and their underlying declarations are mapped to the
27112 same constraint information.
27114 FIXME: This is defined in pt.c because garbage collection
27115 code is not being generated for constraint.cc. */
27119 /* Returns the template constraints of declaration T. If T is not
27120 constrained, return NULL_TREE. Note that T must be non-null. */
27122 tree
27124 {
27135 else
27137 }
27139 /* Associate the given constraint information CI with the declaration
27140 T. If T is a template, then the constraints are associated with
27141 its underlying declaration. Don't build associations if CI is
27142 NULL_TREE. */
27144 void
27146 {
27158 }
27160 /* Remove the associated constraints of the declaration T. */
27162 void
27164 {
27173 }
27175 /* Memoized satisfaction results for declarations. This
27176 maps the pair (constraint_info, arguments) to the result computed
27177 by constraints_satisfied_p. */
27180 {
27181 tree ci;
27182 tree args;
27183 tree result;
27184 };
27186 /* Hashing function and equality for constraint entries. */
27189 {
27191 {
27194 }
27197 {
27199 }
27200 };
27202 /* Memoized satisfaction results for concept checks. */
27205 {
27206 tree tmpl;
27207 tree args;
27208 tree result;
27209 };
27211 /* Hashing function and equality for constraint entries. */
27214 {
27216 {
27218 }
27221 {
27226 }
27227 };
27232 /* Search for a memoized satisfaction result. Returns one of the
27233 truth value nodes if previously memoized, or NULL_TREE otherwise. */
27235 tree
27237 {
27242 else
27244 }
27246 /* Memoize the result of a satisfication test. Returns the saved result. */
27248 tree
27250 {
27257 }
27259 /* Search for a memoized satisfaction result for a concept. */
27261 tree
27263 {
27268 else
27270 }
27272 /* Memoize the result of a concept check. Returns the saved result. */
27274 tree
27276 {
27283 }
27287 /* Returns a prior concept specialization. This returns the substituted
27288 and normalized constraints defined by the concept. */
27290 tree
27292 {
27297 else
27299 }
27301 /* Save a concept expansion for later. */
27303 tree
27305 {
27312 }
27314 static hashval_t
27316 {
27325 }
27327 /* Compare the constraints of two subsumption entries. The LEFT1 and
27328 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
27329 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
27331 static bool
27333 {
27341 }
27343 /* Key/value pair for learning and memoizing subsumption results. This
27344 associates a pair of check constraints (including arguments) with
27345 a boolean value indicating the result. */
27348 {
27349 tree t1;
27350 tree t2;
27352 };
27354 /* Hashing function and equality for constraint entries. */
27357 {
27359 {
27361 }
27364 {
27369 }
27370 };
27374 /* Search for a previously cached subsumption result. */
27378 {
27383 else
27385 }
27387 /* Save a subsumption result. */
27389 bool
27391 {
27398 }
27400 /* Set up the hash table for constraint association. */
27402 void
27404 {
27413 }
27415 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
27416 0..N-1. */
27418 void
27420 {
27423 integer_type_node,
27424 NULL_TREE),
27428 }
27430 /* Set up the hash tables for template instantiations. */
27432 void
27434 {
27440 }
27442 /* Print stats about the template hash tables for -fstats. */
27444 void
27446 {
27455 }
27457 #if CHECKING_P
27461 /* Verify that build_non_dependent_expr () works, for various expressions,
27462 and that location wrappers don't affect the results. */
27464 static void
27466 {
27469 /* Verify constants, without and with location wrappers. */
27486 }
27488 /* Verify that type_dependent_expression_p () works correctly, even
27489 in the presence of location wrapper nodes. */
27491 static void
27493 {
27498 /* If no templates are involved, nothing is type-dependent. */
27504 /* Within a template, an unresolved name is always type-dependent. */
27507 /* Ensure it copes with NULL_TREE and errors. */
27511 /* A USING_DECL in a template should be type-dependent, even if wrapped
27512 with a location wrapper (PR c++/83799). */
27521 }
27523 /* Run all of the selftests within this file. */
27525 void
27527 {
27530 }