| blob | 89024c10fe2ba5aa8e618c78bd987575072ff3c8 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
50 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
51 instantiations have been deferred, either because their definitions
52 were not yet available, or because we were putting off doing the work. */
56 };
71 /* Live only within one (recursive) call to tsubst_expr. We use
72 this to pass the statement expression node from the STMT_EXPR
73 to the EXPR_STMT that is its result. */
76 // -------------------------------------------------------------------------- //
77 // Local Specialization Stack
78 //
79 // Implementation of the RAII helper for creating new local
80 // specializations.
83 {
86 else
88 }
91 {
94 }
96 /* True if we've recursed into fn_type_unification too many times. */
100 {
101 tree tmpl;
102 tree args;
103 tree spec;
104 };
107 {
110 };
116 /* Contains canonical template parameter types. The vector is indexed by
117 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
118 TREE_LIST, whose TREE_VALUEs contain the canonical template
119 parameters of various types and levels. */
122 #define UNIFY_ALLOW_NONE 0
123 #define UNIFY_ALLOW_MORE_CV_QUAL 1
124 #define UNIFY_ALLOW_LESS_CV_QUAL 2
125 #define UNIFY_ALLOW_DERIVED 4
126 #define UNIFY_ALLOW_INTEGER 8
127 #define UNIFY_ALLOW_OUTER_LEVEL 16
128 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
129 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
132 tbr_incomplete_type,
133 tbr_ambiguous_baseclass,
134 tbr_success
135 };
158 tree);
215 location_t);
227 /* Make the current scope suitable for access checking when we are
228 processing T. T can be FUNCTION_DECL for instantiated function
229 template, VAR_DECL for static member variable, or TYPE_DECL for
230 alias template (needed by instantiate_decl). */
232 static void
234 {
242 else
246 {
247 saved_access_scope = tree_cons
250 }
251 }
253 /* Restore the scope set up by push_access_scope. T is the node we
254 are processing. */
256 static void
258 {
260 {
263 }
267 else
269 }
271 /* Do any processing required when DECL (a member template
272 declaration) is finished. Returns the TEMPLATE_DECL corresponding
273 to DECL, unless it is a specialization, in which case the DECL
274 itself is returned. */
276 tree
278 {
285 {
286 tree type;
294 {
298 }
300 }
304 {
306 {
309 }
310 else
312 }
313 else
317 }
319 /* Create a template info node. */
321 tree
323 {
328 }
330 /* Return the template info node corresponding to T, whatever T is. */
332 tree
334 {
356 }
358 /* Returns the template nesting level of the indicated class TYPE.
360 For example, in:
361 template <class T>
362 struct A
363 {
364 template <class U>
365 struct B {};
366 };
368 A<T>::B<U> has depth two, while A<T> has depth one.
369 Both A<T>::B<int> and A<int>::B<U> have depth one, if
370 they are instantiations, not specializations.
372 This function is guaranteed to return 0 if passed NULL_TREE so
373 that, for example, `template_class_depth (current_class_type)' is
374 always safe. */
376 int
378 {
382 {
393 else
395 }
398 }
400 /* Subroutine of maybe_begin_member_template_processing.
401 Returns true if processing DECL needs us to push template parms. */
403 static bool
405 {
411 }
413 /* Subroutine of maybe_begin_member_template_processing.
414 Push the template parms in PARMS, starting from LEVELS steps into the
415 chain, and ending at the beginning, since template parms are listed
416 innermost first. */
418 static void
420 {
428 current_template_parms
434 NULL);
436 {
445 {
452 /* Push the CONST_DECL. */
458 }
459 }
460 }
462 /* Restore the template parameter context for a member template, a
463 friend template defined in a class definition, or a non-template
464 member of template class. */
466 void
468 {
469 tree parms;
474 {
477 /* Disregard full specializations (c++/60999). */
480 }
483 {
488 {
491 }
494 }
496 /* Remember how many levels of template parameters we pushed so that
497 we can pop them later. */
499 }
501 /* Undo the effects of maybe_begin_member_template_processing. */
503 void
505 {
514 {
518 }
519 }
521 /* Return a new template argument vector which contains all of ARGS,
522 but has as its innermost set of arguments the EXTRA_ARGS. */
524 static tree
526 {
527 tree new_args;
545 }
547 /* Like add_to_template_args, but only the outermost ARGS are added to
548 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
549 (EXTRA_ARGS) levels are added. This function is used to combine
550 the template arguments from a partial instantiation with the
551 template arguments used to attain the full instantiation from the
552 partial instantiation. */
554 static tree
556 {
557 tree new_args;
559 /* If there are more levels of EXTRA_ARGS than there are ARGS,
560 something very fishy is going on. */
563 /* If *all* the new arguments will be the EXTRA_ARGS, just return
564 them. */
568 /* For the moment, we make ARGS look like it contains fewer levels. */
573 /* Now, we restore ARGS to its full dimensions. */
577 }
579 /* Return the N levels of innermost template arguments from the ARGS. */
581 tree
583 {
584 tree new_args;
590 /* If N is 1, just return the innermost set of template arguments. */
594 /* If we're not removing anything, just return the arguments we were
595 given. */
601 /* Make a new set of arguments, not containing the outer arguments. */
608 }
610 /* The inverse of get_innermost_template_args: Return all but the innermost
611 EXTRA_LEVELS levels of template arguments from the ARGS. */
613 static tree
615 {
616 tree new_args;
622 /* If N is 1, just return the outermost set of template arguments. */
626 /* If we're not removing anything, just return the arguments we were
627 given. */
632 /* Make a new set of arguments, not containing the inner arguments. */
639 }
641 /* We've got a template header coming up; push to a new level for storing
642 the parms. */
644 void
646 {
647 /* We use a non-tag-transparent scope here, which causes pushtag to
648 put tags in this scope, rather than in the enclosing class or
649 namespace scope. This is the right thing, since we want
650 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
651 global template class, push_template_decl handles putting the
652 TEMPLATE_DECL into top-level scope. For a nested template class,
653 e.g.:
655 template <class T> struct S1 {
656 template <class T> struct S2 {};
657 };
659 pushtag contains special code to insert the TEMPLATE_DECL for S2
660 at the right scope. */
666 /* Add a dummy parameter level while we process the parameter list. */
667 current_template_parms
670 current_template_parms);
671 }
673 /* This routine is called when a specialization is declared. If it is
674 invalid to declare a specialization here, an error is reported and
675 false is returned, otherwise this routine will return true. */
677 static bool
679 {
682 /* [temp.expl.spec]
684 An explicit specialization shall be declared in the namespace of
685 which the template is a member, or, for member templates, in the
686 namespace of which the enclosing class or enclosing class
687 template is a member. An explicit specialization of a member
688 function, member class or static data member of a class template
689 shall be declared in the namespace of which the class template
690 is a member. */
692 {
695 }
697 /* [temp.expl.spec]
699 In an explicit specialization declaration for a member of a class
700 template or a member template that appears in namespace scope,
701 the member template and some of its enclosing class templates may
702 remain unspecialized, except that the declaration shall not
703 explicitly specialize a class member template if its enclosing
704 class templates are not explicitly specialized as well. */
706 {
709 }
712 }
714 /* We've just seen template <>. */
716 bool
718 {
722 }
724 /* Called at then end of processing a declaration preceded by
725 template<>. */
727 void
729 {
732 }
734 /* Any template <>'s that we have seen thus far are not referring to a
735 function specialization. */
737 void
739 {
742 }
744 /* We've just seen a template header. If SPECIALIZATION is nonzero,
745 it was of the form template <>. */
747 static void
749 {
751 template_header_count++;
752 }
754 /* We're beginning an explicit instantiation. */
756 void
758 {
761 }
764 void
766 {
769 }
771 /* An explicit specialization or partial specialization of TMPL is being
772 declared. Check that the namespace in which the specialization is
773 occurring is permissible. Returns false iff it is invalid to
774 specialize TMPL in the current namespace. */
776 static bool
778 {
781 /* [tmpl.expl.spec]
783 An explicit specialization shall be declared in a namespace enclosing the
784 specialized template. An explicit specialization whose declarator-id is
785 not qualified shall be declared in the nearest enclosing namespace of the
786 template, or, if the namespace is inline (7.3.1), any namespace from its
787 enclosing namespace set. */
790 {
793 }
796 /* Same or enclosing namespace. */
798 else
799 {
805 }
806 }
808 /* SPEC is an explicit instantiation. Check that it is valid to
809 perform this explicit instantiation in the current namespace. */
811 static void
813 {
814 tree ns;
816 /* DR 275: An explicit instantiation shall appear in an enclosing
817 namespace of its template. */
823 }
825 // Returns the type of a template specialization only if that
826 // specialization needs to be defined. Otherwise (e.g., if the type has
827 // already been defined), the function returns NULL_TREE.
828 static tree
830 {
831 // An implicit instantiation of an incomplete type implies
832 // the definition of a new class template.
833 //
834 // template<typename T>
835 // struct S;
836 //
837 // template<typename T>
838 // struct S<T*>;
839 //
840 // Here, S<T*> is an implicit instantiation of S whose type
841 // is incomplete.
845 // It can also be the case that TYPE is a completed specialization.
846 // Continuing the previous example, suppose we also declare:
847 //
848 // template<typename T>
849 // requires Integral<T>
850 // struct S<T*>;
851 //
852 // Here, S<T*> refers to the specialization S<T*> defined
853 // above. However, we need to differentiate definitions because
854 // we intend to define a new partial specialization. In this case,
855 // we rely on the fact that the constraints are different for
856 // this declaration than that above.
857 //
858 // Note that we also get here for injected class names and
859 // late-parsed template definitions. We must ensure that we
860 // do not create new type declarations for those cases.
862 {
866 // If there are no template parameters, this cannot be a new
867 // partial template specializtion?
871 // The injected-class-name is not a new partial specialization.
875 // If the constraints are not the same as those of the primary
876 // then, we can probably create a new specialization.
880 {
884 }
886 // Also, if there's a pre-existing specialization with matching
887 // constraints, then this also isn't new.
890 {
898 }
900 // Create a new type node (and corresponding type decl)
901 // for the newly declared specialization.
906 /* We only need a separate type node for storing the definition of this
907 partial specialization; uses of S<T*> are unconstrained, so all are
908 equivalent. So keep TYPE_CANONICAL the same. */
911 // Build the corresponding type decl.
917 }
920 }
922 /* The TYPE is being declared. If it is a template type, that means it
923 is a partial specialization. Do appropriate error-checking. */
925 tree
927 {
928 tree context;
933 /* A lambda that appears in specialization context is not itself a
934 specialization. */
939 {
943 }
948 {
954 else
957 }
959 {
960 /* This is for ordinary explicit specialization and partial
961 specialization of a template class such as:
963 template <> class C<int>;
965 or:
967 template <class T> class C<T*>;
969 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
972 {
979 {
984 }
985 }
991 /* Trying to define a specialization either without a template<> header
992 or in an inappropriate place. We've already given an error, so just
993 bail now so we don't actually define the specialization. */
995 }
1001 {
1002 /* This is for an explicit specialization of member class
1003 template according to [temp.expl.spec/18]:
1005 template <> template <class U> class C<int>::D;
1007 The context `C<int>' must be an implicit instantiation.
1008 Otherwise this is just a member class template declared
1009 earlier like:
1011 template <> class C<int> { template <class U> class D; };
1012 template <> template <class U> class C<int>::D;
1014 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1015 while in the second case, `C<int>::D' is a primary template
1016 and `C<T>::D' may not exist. */
1020 {
1021 tree t;
1026 {
1031 }
1033 /* Check for invalid specialization after instantiation:
1035 template <> template <> class C<int>::D<int>;
1036 template <> template <class U> class C<int>::D; */
1040 {
1044 {
1045 /* We already have a full specialization of this partial
1046 instantiation, or a full specialization has been
1047 looked up but not instantiated. Reassign it to the
1048 new member specialization template. */
1049 spec_entry elt;
1061 spec_entry **slot
1066 }
1067 else
1068 /* But if we've had an implicit instantiation, that's a
1069 problem ([temp.expl.spec]/6). */
1072 }
1074 /* Mark TYPE as a specialization. And as a result, we only
1075 have one level of template argument for the innermost
1076 class template. */
1081 }
1082 }
1084 {
1085 /* Someday C++0x may allow for enum template specialization. */
1090 else
1091 {
1094 }
1095 }
1098 }
1100 /* Returns nonzero if we can optimize the retrieval of specializations
1101 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1102 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1106 {
1109 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1110 parameter. */
1112 /* The optimized lookup depends on the fact that the
1113 template arguments for the member function template apply
1114 purely to the containing class, which is not true if the
1115 containing class is an explicit or partial
1116 specialization. */
1120 /* It is possible to have a template that is not a member
1121 template and is not a member of a template class:
1123 template <typename T>
1124 struct S { friend A::f(); };
1126 Here, the friend function is a template, but the context does
1127 not have template information. The optimized lookup relies
1128 on having ARGS be the template arguments for both the class
1129 and the function template. */
1131 }
1133 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1134 gone through coerce_template_parms by now. */
1136 static void
1138 {
1141 {
1144 {
1151 /* Allow typedefs on the type of a non-type argument, since a
1153 else
1155 }
1156 }
1158 }
1160 /* Retrieve the specialization (in the sense of [temp.spec] - a
1161 specialization is either an instantiation or an explicit
1162 specialization) of TMPL for the given template ARGS. If there is
1163 no such specialization, return NULL_TREE. The ARGS are a vector of
1164 arguments, or a vector of vectors of arguments, in the case of
1165 templates with more than one level of parameters.
1167 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1168 then we search for a partial specialization matching ARGS. This
1169 parameter is ignored if TMPL is not a class template.
1171 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1172 result is a NONTYPE_ARGUMENT_PACK. */
1174 static tree
1176 {
1186 /* There should be as many levels of arguments as there are
1187 levels of parameters. */
1196 /* Lambda functions in templates aren't instantiated normally, but through
1197 tsubst_lambda_expr. */
1202 {
1203 /* The template arguments actually apply to the containing
1204 class. Find the class specialization with those
1205 arguments. */
1207 tree class_specialization
1212 /* Find the instance of TMPL. */
1215 {
1218 /* using-declarations can add base methods to the method vec,
1219 and we don't want those here. */
1222 }
1224 }
1225 else
1226 {
1228 spec_entry elt;
1237 else
1245 }
1248 }
1250 /* Like retrieve_specialization, but for local declarations. */
1252 tree
1254 {
1260 }
1262 /* Returns nonzero iff DECL is a specialization of TMPL. */
1264 int
1266 {
1267 tree t;
1270 {
1276 }
1277 else
1278 {
1287 }
1290 }
1292 /* Returns nonzero iff DECL is a specialization of friend declaration
1293 FRIEND_DECL according to [temp.friend]. */
1295 bool
1297 {
1304 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1305 of a template class, we want to check if DECL is a specialization
1306 if this. */
1310 {
1311 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1314 }
1319 /* There is nothing to do if this is not a template friend. */
1326 /* [temp.friend/6]
1327 A member of a class template may be declared to be a friend of a
1328 non-template class. In this case, the corresponding member of
1329 every specialization of the class template is a friend of the
1330 class granting friendship.
1332 For example, given a template friend declaration
1334 template <class T> friend void A<T>::f();
1336 the member function below is considered a friend
1338 template <> struct A<int> {
1339 void f();
1340 };
1342 For this type of template friend, TEMPLATE_DEPTH below will be
1343 nonzero. To determine if DECL is a friend of FRIEND, we first
1344 check if the enclosing class is a specialization of another. */
1351 {
1352 /* Next, we check the members themselves. In order to handle
1353 a few tricky cases, such as when FRIEND_DECL's are
1355 template <class T> friend void A<T>::g(T t);
1356 template <class T> template <T t> friend void A<T>::h();
1358 and DECL's are
1360 void A<int>::g(int);
1361 template <int> void A<int>::h();
1363 we need to figure out ARGS, the template arguments from
1364 the context of DECL. This is required for template substitution
1365 of `T' in the function parameter of `g' and template parameter
1366 of `h' in the above examples. Here ARGS corresponds to `int'. */
1373 {
1375 {
1378 else
1380 current_depth++;
1381 }
1383 }
1386 {
1388 tree friend_type;
1389 tree decl_type;
1390 tree friend_args_type;
1391 tree decl_args_type;
1393 /* Make sure that both DECL and FRIEND_DECL are templates or
1394 non-templates. */
1400 {
1401 /* If both are templates, check template parameter list. */
1402 tree friend_parms
1407 friend_parms))
1411 }
1412 else
1420 /* Check if return types match. */
1424 /* Check if function parameter types match, ignoring the
1425 `this' parameter. */
1434 }
1435 else
1436 {
1437 /* DECL is a TYPE_DECL */
1441 /* Make sure that both DECL and FRIEND_DECL are templates or
1442 non-templates. */
1443 is_template
1450 {
1451 tree friend_parms;
1452 /* If both are templates, check the name of the two
1453 TEMPLATE_DECL's first because is_friend didn't. */
1458 /* Now check template parameter list. */
1459 friend_parms
1462 return comp_template_parms
1464 friend_parms);
1465 }
1466 else
1469 }
1470 }
1472 }
1474 /* Register the specialization SPEC as a specialization of TMPL with
1475 the indicated ARGS. IS_FRIEND indicates whether the specialization
1476 is actually just a friend declaration. ATTRLIST is the list of
1477 attributes that the specialization is declared with or NULL when
1478 it isn't. Returns SPEC, or an equivalent prior declaration, if
1479 available.
1481 We also store instantiations of field packs in the hash table, even
1482 though they are not themselves templates, to make lookup easier. */
1484 static tree
1486 hashval_t hash)
1487 {
1488 tree fn;
1490 spec_entry elt;
1498 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1499 register it; we want the corresponding TEMPLATE_DECL instead.
1500 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1501 the more obvious `uses_template_parms (spec)' to avoid problems
1502 with default function arguments. In particular, given
1503 something like this:
1505 template <class T> void f(T t1, T t = T())
1507 the default argument expression is not substituted for in an
1508 instantiation unless and until it is actually needed. */
1512 /* We don't put these specializations in the hash table, but we might
1513 want to give an error about a mismatch. */
1515 else
1516 {
1524 slot =
1528 else
1530 }
1532 /* We can sometimes try to re-register a specialization that we've
1533 already got. In particular, regenerate_decl_from_template calls
1534 duplicate_decls which will update the specialization list. But,
1535 we'll still get called again here anyhow. It's more convenient
1536 to simply allow this than to try to prevent it. */
1540 {
1542 {
1545 {
1547 fn);
1549 }
1550 else
1551 {
1552 tree clone;
1553 /* This situation should occur only if the first
1554 specialization is an implicit instantiation, the
1555 second is an explicit specialization, and the
1556 implicit instantiation has not yet been used. That
1557 situation can occur if we have implicitly
1558 instantiated a member function and then specialized
1559 it later.
1561 We can also wind up here if a friend declaration that
1562 looked like an instantiation turns out to be a
1563 specialization:
1565 template <class T> void foo(T);
1566 class S { friend void foo<>(int) };
1567 template <> void foo(int);
1569 We transform the existing DECL in place so that any
1570 pointers to it become pointers to the updated
1571 declaration.
1573 If there was a definition for the template, but not
1574 for the specialization, we want this to look as if
1575 there were no definition, and vice versa. */
1578 /* The call to duplicate_decls will have applied
1579 [temp.expl.spec]:
1581 An explicit specialization of a function template
1582 is inline only if it is explicitly declared to be,
1583 and independently of whether its function template
1584 is.
1586 to the primary function; now copy the inline bits to
1587 the various clones. */
1589 {
1596 }
1600 }
1601 }
1603 {
1606 /* We've already complained in duplicate_decls. */
1610 /* Dup decl failed, but this is a new definition. Set the
1611 line number so any errors match this new
1612 definition. */
1616 }
1617 }
1621 /* A specialization must be declared in the same namespace as the
1622 template it is specializing. */
1628 {
1637 /* If TMPL is a forward declaration of a template function, keep a list
1638 of all specializations in case we need to reassign them to a friend
1639 template later in tsubst_friend_function.
1641 Also keep a list of all variable template instantiations so that
1642 process_partial_specialization can check whether a later partial
1643 specialization would have used it. */
1646 }
1649 }
1651 /* Returns true iff two spec_entry nodes are equivalent. */
1655 bool
1657 {
1664 /* tmpl could be a FIELD_DECL for a capture pack. */
1668 {
1669 /* Partial specializations of a variable template can be distinguished by
1670 constraints. */
1674 }
1678 }
1680 /* Returns a hash for a template TMPL and template arguments ARGS. */
1682 static hashval_t
1684 {
1687 }
1689 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1690 ignoring SPEC. */
1692 hashval_t
1694 {
1696 }
1698 /* Recursively calculate a hash value for a template argument ARG, for use
1699 in the hash tables of template specializations. */
1701 hashval_t
1703 {
1723 {
1731 {
1736 }
1758 {
1762 {
1765 }
1767 }
1771 {
1774 }
1785 val = iterative_hash_template_arg
1797 val);
1799 val);
1808 /* A lambda can't appear in a template arg, but don't crash on
1809 erroneous input. */
1821 /* Now hash operands as usual. */
1826 }
1829 {
1832 {
1833 // We want an alias specialization that survived strip_typedefs
1834 // to hash differently from its TYPE_CANONICAL, to avoid hash
1835 // collisions that compare as different in template_args_equal.
1836 // These could be dependent specializations that strip_typedefs
1837 // left alone, or untouched specializations because
1838 // coerce_template_parms returns the unconverted template
1839 // arguments if it sees incomplete argument packs.
1842 }
1845 val);
1848 /* Otherwise just compare the types during lookup. */
1857 {
1862 }
1863 }
1866 }
1868 /* Unregister the specialization SPEC as a specialization of TMPL.
1869 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1870 if the SPEC was listed as a specialization of TMPL.
1872 Note that SPEC has been ggc_freed, so we can't look inside it. */
1874 bool
1876 {
1878 spec_entry elt;
1886 {
1891 }
1894 }
1896 /* Like register_specialization, but for local declarations. We are
1897 registering SPEC, an instantiation of TMPL. */
1899 void
1901 {
1904 }
1906 /* TYPE is a class type. Returns true if TYPE is an explicitly
1907 specialized class. */
1909 bool
1911 {
1915 }
1917 /* Print the list of functions at FNS, going through all the overloads
1918 for each element of the list. Alternatively, FNS can not be a
1919 TREE_LIST, in which case it will be printed together with all the
1920 overloads.
1922 MORE and *STR should respectively be FALSE and NULL when the function
1923 is called from the outside. They are used internally on recursive
1924 calls. print_candidates manages the two parameters and leaves NULL
1925 in *STR when it ends. */
1927 static void
1929 {
1933 else
1935 {
1941 {
1944 else
1947 }
1949 }
1950 }
1952 /* Print the list of candidate FNS in an error message. FNS can also
1953 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1955 void
1957 {
1961 }
1963 /* Get a (possibly) constrained template declaration for the
1964 purpose of ordering candidates. */
1965 static tree
1967 {
1973 }
1975 /* Among candidates having the same signature, return the
1976 most constrained or NULL_TREE if there is no best candidate.
1977 If the signatures of candidates vary (e.g., template
1978 specialization vs. member function), then there can be no
1979 most constrained.
1981 Note that we don't compare constraints on the functions
1982 themselves, but rather those of their templates. */
1983 static tree
1985 {
1986 // Try to find the best candidate in a first pass.
1989 {
1996 }
1998 // Verify that the champ is better than previous candidates.
2003 }
2006 }
2009 /* Returns the template (one of the functions given by TEMPLATE_ID)
2010 which can be specialized to match the indicated DECL with the
2011 explicit template args given in TEMPLATE_ID. The DECL may be
2012 NULL_TREE if none is available. In that case, the functions in
2013 TEMPLATE_ID are non-members.
2015 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2016 specialization of a member template.
2018 The TEMPLATE_COUNT is the number of references to qualifying
2019 template classes that appeared in the name of the function. See
2020 check_explicit_specialization for a more accurate description.
2022 TSK indicates what kind of template declaration (if any) is being
2023 declared. TSK_TEMPLATE indicates that the declaration given by
2024 DECL, though a FUNCTION_DECL, has template parameters, and is
2025 therefore a template function.
2027 The template args (those explicitly specified and those deduced)
2028 are output in a newly created vector *TARGS_OUT.
2030 If it is impossible to determine the result, an error message is
2031 issued. The error_mark_node is returned to indicate failure. */
2033 static tree
2035 tree decl,
2039 tmpl_spec_kind tsk)
2040 {
2041 tree fns;
2042 tree targs;
2043 tree explicit_targs;
2046 /* A TREE_LIST of templates of which DECL may be a specialization.
2047 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2048 corresponding TREE_PURPOSE is the set of template arguments that,
2049 when used to instantiate the template, would produce a function
2050 with the signature of DECL. */
2060 /* We shouldn't be specializing a member template of an
2061 unspecialized class template; we already gave an error in
2062 check_specialization_scope, now avoid crashing. */
2066 {
2069 }
2077 /* Check for baselinks. */
2082 {
2085 }
2087 {
2090 }
2092 /* Count the number of template headers specified for this
2093 specialization. */
2103 {
2106 tf_warning_or_error,
2110 }
2112 {
2116 {
2117 tree decl_arg_types;
2118 tree fn_arg_types;
2119 tree insttype;
2121 /* In case of explicit specialization, we need to check if
2122 the number of template headers appearing in the specialization
2123 is correct. This is usually done in check_explicit_specialization,
2124 but the check done there cannot be exhaustive when specializing
2125 member functions. Consider the following code:
2127 template <> void A<int>::f(int);
2128 template <> template <> void A<int>::f(int);
2130 Assuming that A<int> is not itself an explicit specialization
2131 already, the first line specializes "f" which is a non-template
2132 member function, whilst the second line specializes "f" which
2133 is a template member function. So both lines are syntactically
2134 correct, and check_explicit_specialization does not reject
2135 them.
2137 Here, we can do better, as we are matching the specialization
2138 against the declarations. We count the number of template
2139 headers, and we check if they match TEMPLATE_COUNT + 1
2140 (TEMPLATE_COUNT is the number of qualifying template classes,
2141 plus there must be another header for the member template
2142 itself).
2144 Notice that if header_count is zero, this is not a
2145 specialization but rather a template instantiation, so there
2146 is no check we can perform here. */
2150 /* Check that the number of template arguments at the
2151 innermost level for DECL is the same as for FN. */
2159 /* DECL might be a specialization of FN. */
2163 /* For a non-static member function, we need to make sure
2164 that the const qualification is the same. Since
2165 get_bindings does not try to merge the "this" parameter,
2166 we must do the comparison explicitly. */
2168 {
2173 /* And the ref-qualification. */
2177 }
2179 /* Skip the "this" parameter and, for constructors of
2180 classes with virtual bases, the VTT parameter. A
2181 full specialization of a constructor will have a VTT
2182 parameter, but a template never will. */
2183 decl_arg_types
2185 fn_arg_types
2188 /* Function templates cannot be specializations; there are
2189 no partial specializations of functions. Therefore, if
2190 the type of DECL does not match FN, there is no
2191 match.
2193 Note that it should never be the case that we have both
2194 candidates added here, and for regular member functions
2195 below. */
2197 {
2201 }
2203 /* See whether this function might be a specialization of this
2204 template. Suppress access control because we might be trying
2205 to make this specialization a friend, and we have already done
2206 access control for the declaration of the specialization. */
2212 /* We cannot deduce template arguments that when used to
2213 specialize TMPL will produce DECL. */
2217 /* We deduced something involving 'auto', which isn't a valid
2218 template argument. */
2221 /* Remove, from the set of candidates, all those functions
2222 whose constraints are not satisfied. */
2226 // Then, try to form the new function type.
2230 fn_arg_types
2235 /* Save this template, and the arguments deduced. */
2237 }
2239 /* FN is an ordinary member function, and we need a
2240 specialization of a member template. */
2241 ;
2243 /* We can get IDENTIFIER_NODEs here in certain erroneous
2244 cases. */
2245 ;
2247 /* This is just an ordinary non-member function. Nothing can
2248 be a specialization of that. */
2249 ;
2251 /* Cannot specialize functions that are created implicitly. */
2252 ;
2253 else
2254 {
2255 tree decl_arg_types;
2257 /* This is an ordinary member function. However, since
2258 we're here, we can assume its enclosing class is a
2259 template class. For example,
2261 template <typename T> struct S { void f(); };
2262 template <> void S<int>::f() {}
2264 Here, S<int>::f is a non-template, but S<int> is a
2265 template class. If FN has the same type as DECL, we
2266 might be in business. */
2269 /* Its enclosing class is an explicit specialization
2270 of a template class. This is not a candidate. */
2275 /* The return types differ. */
2278 /* Adjust the type of DECL in case FN is a static member. */
2285 decl_arg_types))
2293 // If the deduced arguments do not satisfy the constraints,
2294 // this is not a candidate.
2298 // Add the candidate.
2300 }
2301 }
2304 {
2305 /* We have:
2307 [temp.expl.spec]
2309 It is possible for a specialization with a given function
2310 signature to be instantiated from more than one function
2311 template. In such cases, explicit specification of the
2312 template arguments must be used to uniquely identify the
2313 function template specialization being specialized.
2315 Note that here, there's no suggestion that we're supposed to
2316 determine which of the candidate templates is most
2317 specialized. However, we, also have:
2319 [temp.func.order]
2321 Partial ordering of overloaded function template
2322 declarations is used in the following contexts to select
2323 the function template to which a function template
2324 specialization refers:
2326 -- when an explicit specialization refers to a function
2327 template.
2329 So, we do use the partial ordering rules, at least for now.
2330 This extension can only serve to make invalid programs valid,
2331 so it's safe. And, there is strong anecdotal evidence that
2332 the committee intended the partial ordering rules to apply;
2333 the EDG front end has that behavior, and John Spicer claims
2334 that the committee simply forgot to delete the wording in
2335 [temp.expl.spec]. */
2338 {
2341 }
2342 }
2344 // Concepts allows multiple declarations of member functions
2345 // with the same signature. Like above, we need to rely on
2346 // on the partial ordering of those candidates to determine which
2347 // is the best.
2349 {
2351 {
2354 }
2355 }
2358 {
2365 else
2368 }
2372 {
2378 }
2380 /* We have one, and exactly one, match. */
2382 {
2386 // Propagate the candidate's constraints to the declaration.
2389 /* DECL is a re-declaration or partial instantiation of a template
2390 function. */
2393 /* It was a specialization of an ordinary member function in a
2394 template class. */
2396 }
2398 /* It was a specialization of a template. */
2401 {
2406 }
2407 else
2410 }
2412 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2413 but with the default argument values filled in from those in the
2414 TMPL_TYPES. */
2416 static tree
2418 tree tmpl_types)
2419 {
2420 tree new_spec_types;
2428 /* Substitute into the rest of the list. */
2429 new_spec_types =
2433 /* Add the default argument for this parameter. */
2436 new_spec_types);
2437 }
2439 /* DECL is an explicit specialization. Replicate default arguments
2440 from the template it specializes. (That way, code like:
2442 template <class T> void f(T = 3);
2443 template <> void f(double);
2444 void g () { f (); }
2446 works, as required.) An alternative approach would be to look up
2447 the correct default arguments at the call-site, but this approach
2448 is consistent with how implicit instantiations are handled. */
2450 static void
2452 {
2453 tree tmpl;
2454 tree spec_types;
2455 tree tmpl_types;
2456 tree new_spec_types;
2457 tree old_type;
2458 tree new_type;
2459 tree t;
2464 /* See if there's anything we need to do. */
2477 {
2478 /* Remove the this pointer, but remember the object's type for
2479 CV quals. */
2485 {
2486 /* DECL may contain more parameters than TMPL due to the extra
2487 in-charge parameter in constructors and destructors. */
2490 }
2492 {
2495 }
2496 }
2498 /* Compute the merged default arguments. */
2499 new_spec_types =
2502 /* Compute the new FUNCTION_TYPE. */
2504 {
2508 new_spec_types);
2511 /* Put the in-charge parameter back. */
2514 new_spec_types);
2518 new_spec_types);
2519 }
2520 else
2522 new_spec_types);
2532 }
2534 /* Return the number of template headers we expect to see for a definition
2535 or specialization of CTYPE or one of its non-template members. */
2537 int
2539 {
2543 {
2544 /* You're supposed to have one `template <...>' for every
2545 template class, but you don't need one for a full
2546 specialization. For example:
2548 template <class T> struct S{};
2549 template <> struct S<int> { void f(); };
2550 void S<int>::f () {}
2552 is correct; there shouldn't be a `template <>' for the
2553 definition of `S<int>::f'. */
2555 /* If CTYPE does not have template information of any
2556 kind, then it is not a template, nor is it nested
2557 within a template. */
2565 }
2568 }
2570 /* Do a simple sanity check on the template headers that precede the
2571 variable declaration DECL. */
2573 void
2575 {
2580 {
2583 "variable templates only available with "
2586 // Namespace-scope variable templates should have a template header.
2588 }
2590 {
2592 "too many template headers for %qD "
2598 "members of an explicitly specialized class are defined "
2600 }
2601 }
2603 /* An explicit specialization whose declarator-id or class-head-name is not
2604 qualified shall be declared in the nearest enclosing namespace of the
2605 template, or, if the namespace is inline (7.3.1), any namespace from its
2606 enclosing namespace set.
2608 If the name declared in the explicit instantiation is an unqualified name,
2609 the explicit instantiation shall appear in the namespace where its template
2610 is declared or, if that namespace is inline (7.3.1), any namespace from its
2611 enclosing namespace set. */
2613 void
2615 {
2620 {
2626 /* This was allowed in C++98, so only pedwarn. */
2628 "outside its namespace must use a nested-name-"
2630 }
2631 }
2633 /* Warn for a template specialization SPEC that is missing some of a set
2634 of function or type attributes that the template TEMPL is declared with.
2635 ATTRLIST is a list of additional attributes that SPEC should be taken
2636 to ultimately be declared with. */
2638 static void
2640 {
2647 /* Avoid warning if either declaration or its type is deprecated. */
2669 /* Avoid warning if the primary has no attributes. */
2673 /* Avoid warning if either declaration contains an attribute on
2674 the white list below. */
2677 };
2685 /* Avoid warning if the difference between the primary and
2686 the specialization is not in one of the attributes below. */
2690 };
2692 /* Put together a list of the black listed attributes that the primary
2693 template is declared with that the specialization is not, in case
2694 it's not apparent from the most recent declaration of the primary. */
2696 pretty_printer str;
2699 {
2701 {
2706 {
2716 }
2717 }
2718 }
2725 spec))
2731 }
2733 /* Check to see if the function just declared, as indicated in
2734 DECLARATOR, and in DECL, is a specialization of a function
2735 template. We may also discover that the declaration is an explicit
2736 instantiation at this point.
2738 Returns DECL, or an equivalent declaration that should be used
2739 instead if all goes well. Issues an error message if something is
2740 amiss. Returns error_mark_node if the error is not easily
2741 recoverable.
2743 FLAGS is a bitmask consisting of the following flags:
2745 2: The function has a definition.
2746 4: The function is a friend.
2748 The TEMPLATE_COUNT is the number of references to qualifying
2749 template classes that appeared in the name of the function. For
2750 example, in
2752 template <class T> struct S { void f(); };
2753 void S<int>::f();
2755 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2756 classes are not counted in the TEMPLATE_COUNT, so that in
2758 template <class T> struct S {};
2759 template <> struct S<int> { void f(); }
2760 template <> void S<int>::f();
2762 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2763 invalid; there should be no template <>.)
2765 If the function is a specialization, it is marked as such via
2766 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2767 is set up correctly, and it is added to the list of specializations
2768 for that template. */
2770 tree
2772 tree decl,
2775 tree attrlist)
2776 {
2785 tmpl_spec_kind tsk;
2788 {
2791 else
2793 }
2794 else
2798 {
2801 {
2804 }
2806 {
2808 /* This could be something like:
2810 template <class T> void f(T);
2811 class S { friend void f<>(int); } */
2813 else
2814 {
2815 /* This case handles bogus declarations like template <>
2816 template <class T> void f<int>(); */
2819 declarator);
2821 }
2822 }
2826 /* The error has already been reported in
2827 check_specialization_scope. */
2833 /* Fall through. */
2846 decl);
2849 else
2853 /* Fall through. */
2859 /* In cases like template<> constexpr bool v = true;
2860 We'll give an error in check_template_variable. */
2866 else
2872 {
2873 /* This case handles bogus declarations like template <>
2874 template <class T> void f<int>(); */
2878 declarator);
2880 {
2881 /* Partial specialization of variable template. */
2885 }
2889 else
2893 ok:;
2894 }
2897 /* This is a specialization of a member template, without
2898 specialization the containing class. Something like:
2900 template <class T> struct S {
2901 template <class U> void f (U);
2902 };
2903 template <> template <class U> void S<int>::f(U) {}
2905 That's a specialization -- but of the entire template. */
2911 }
2914 /* This doesn't apply to variable templates. */
2917 {
2921 {
2925 }
2926 }
2929 {
2934 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2936 {
2937 tree fns;
2942 else
2943 {
2944 /* If there is no class context, the explicit instantiation
2945 must be at namespace scope. */
2948 /* Find the namespace binding, using the declaration
2949 context. */
2953 /* If lookup fails, look for a friend declaration so we can
2954 give a better diagnostic. */
2960 {
2963 }
2964 }
2967 }
2973 {
2975 /* A specialization in class scope. This is invalid,
2976 but the error will already have been flagged by
2977 check_specialization_scope. */
2979 else
2980 {
2981 /* It's not valid to write an explicit instantiation in
2982 class scope, e.g.:
2984 class C { template void f(); }
2986 This case is caught by the parser. However, on
2987 something like:
2989 template class C { void f(); };
2991 (which is invalid) we can get here. The error will be
2992 issued later. */
2993 ;
2994 }
2997 }
3000 {
3001 // We'll match variable templates in start_decl.
3005 /* Find the list of functions in ctype that have the same
3006 name as the declared function. */
3010 {
3014 {
3015 /* From [temp.expl.spec]:
3017 If such an explicit specialization for the member
3018 of a class template names an implicitly-declared
3019 special member function (clause _special_), the
3020 program is ill-formed.
3022 Similar language is found in [temp.explicit]. */
3025 }
3028 }
3030 /* For a type-conversion operator, We might be looking for
3031 `operator int' which will be a specialization of
3032 `operator T'. Grab all the conversion operators, and
3033 then select from them. */
3038 {
3041 }
3042 else
3044 }
3046 /* Figure out what exactly is being specialized at this point.
3047 Note that for an explicit instantiation, even one for a
3048 member function, we cannot tell a priori whether the
3049 instantiation is for a member template, or just a member
3050 function of a template class. Even if a member template is
3051 being instantiated, the member template arguments may be
3052 elided if they can be deduced from the rest of the
3053 declaration. */
3056 member_specialization,
3057 template_count,
3058 tsk);
3061 /* We couldn't figure out what this declaration was
3062 specializing. */
3064 else
3065 {
3068 {
3070 "friend declaration %qD is not visible to "
3074 }
3082 {
3083 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3084 is done by do_decl_instantiation later. */
3090 {
3091 /* If TMPL is not the most general template (for
3092 example, if TMPL is a friend template that is
3093 injected into namespace scope), then there will
3094 be too many levels of TARGS. Remove some of them
3095 here. */
3097 tree new_targs;
3104 }
3107 }
3109 /* If we thought that the DECL was a member function, but it
3110 turns out to be specializing a static member function,
3111 make DECL a static member function as well. */
3117 /* If this is a specialization of a member template of a
3118 template class, we want to return the TEMPLATE_DECL, not
3119 the specialization of it. */
3121 {
3126 {
3127 tree parm;
3131 /* We want to use the argument list specified in the
3132 definition, not in the original declaration. */
3137 }
3140 }
3142 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3148 /* Inherit default function arguments from the template
3149 DECL is specializing. */
3153 /* This specialization has the same protection as the
3154 template it specializes. */
3158 /* 7.1.1-1 [dcl.stc]
3160 A storage-class-specifier shall not be specified in an
3161 explicit specialization...
3163 The parser rejects these, so unless action is taken here,
3164 explicit function specializations will always appear with
3165 global linkage.
3167 The action recommended by the C++ CWG in response to C++
3168 defect report 605 is to make the storage class and linkage
3169 of the explicit specialization match the templated function:
3171 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3172 */
3174 {
3178 /* A concept cannot be specialized. */
3180 {
3182 gen_tmpl);
3184 }
3186 /* This specialization has the same linkage and visibility as
3187 the function template it specializes. */
3190 {
3193 }
3196 {
3199 }
3200 }
3202 /* If DECL is a friend declaration, declared using an
3203 unqualified name, the namespace associated with DECL may
3204 have been set incorrectly. For example, in:
3206 template <typename T> void f(T);
3207 namespace N {
3208 struct S { friend void f<int>(int); }
3209 }
3211 we will have set the DECL_CONTEXT for the friend
3212 declaration to N, rather than to the global namespace. */
3217 /* This is not really a declaration of a specialization.
3218 It's just the name of an instantiation. But, it's not
3219 a request for an instantiation, either. */
3222 /* A specialization is not necessarily COMDAT. */
3228 /* If this is a full specialization, register it so that we can find
3229 it again. Partial specializations will be registered in
3230 process_partial_specialization. */
3232 {
3237 }
3240 /* A 'structor should already have clones. */
3246 }
3247 }
3250 }
3252 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3253 parameters. These are represented in the same format used for
3254 DECL_TEMPLATE_PARMS. */
3256 int
3258 {
3259 const_tree p1;
3260 const_tree p2;
3268 {
3280 {
3284 /* If either of the template parameters are invalid, assume
3285 they match for the sake of error recovery. */
3298 }
3299 }
3302 /* One set of parameters has more parameters lists than the
3303 other. */
3307 }
3309 /* Determine whether PARM is a parameter pack. */
3311 bool
3313 {
3314 /* Determine if we have a non-type template parameter pack. */
3321 /* If this is a list of template parameters, we could get a
3322 TYPE_DECL or a TEMPLATE_DECL. */
3326 /* Otherwise it must be a type template parameter. */
3330 }
3332 /* Determine if T is a function parameter pack. */
3334 bool
3336 {
3340 }
3342 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3343 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3345 tree
3347 {
3354 }
3356 /* Return true iff the function parameter PARAM_DECL was expanded
3357 from the function parameter pack PACK. */
3359 bool
3361 {
3366 /* The parameter pack and its pack arguments have the same
3367 DECL_PARM_INDEX. */
3369 }
3371 /* Determine whether ARGS describes a variadic template args list,
3372 i.e., one that is terminated by a template argument pack. */
3374 static bool
3376 {
3378 tree last_parm;
3392 }
3394 /* Generate a new name for the parameter pack name NAME (an
3395 IDENTIFIER_NODE) that incorporates its */
3397 static tree
3399 {
3400 /* Munge the name to include the parameter index. */
3401 #define NUMBUF_LEN 128
3415 }
3417 /* Return true if T is a primary function, class or alias template
3418 specialization, not including the template pattern. */
3420 bool
3422 {
3438 }
3440 /* Return true if PARM is a template template parameter. */
3442 bool
3444 {
3446 }
3448 /* Return true iff PARM is a DECL representing a type template
3449 parameter. */
3451 bool
3453 {
3458 }
3460 /* Return the template parameters of T if T is a
3461 primary template instantiation, NULL otherwise. */
3463 tree
3465 {
3470 parms = INNERMOST_TEMPLATE_PARMS
3474 }
3476 /* Return the template parameters of the LEVELth level from the full list
3477 of template parameters PARMS. */
3479 tree
3481 {
3482 tree p;
3493 }
3495 /* Returns the template arguments of T if T is a template instantiation,
3496 NULL otherwise. */
3498 tree
3500 {
3508 }
3510 /* Return the argument pack elements of T if T is a template argument pack,
3511 NULL otherwise. */
3513 tree
3515 {
3521 }
3523 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3524 ARGUMENT_PACK_SELECT represents. */
3526 static tree
3528 {
3532 /* If the selected argument is an expansion E, that most likely means we were
3533 called from gen_elem_of_pack_expansion_instantiation during the
3534 substituting of an argument pack (of which the Ith element is a pack
3535 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3536 In this case, the Ith element resulting from this substituting is going to
3537 be a pack expansion, which pattern is the pattern of E. Let's return the
3538 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3539 resulting pack expansion from it. */
3541 {
3542 /* Make sure we aren't throwing away arg info. */
3545 }
3548 }
3551 /* True iff FN is a function representing a built-in variadic parameter
3552 pack. */
3554 bool
3556 {
3566 }
3568 /* True iff CALL is a call to a function representing a built-in variadic
3569 parameter pack. */
3571 static bool
3573 {
3577 }
3579 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3581 static tree
3583 tree in_decl)
3584 {
3590 {
3592 {
3595 }
3600 }
3601 else
3602 {
3606 /* Calculate the largest value of len that won't make the size of the vec
3607 overflow an int. The compiler will exceed resource limits long before
3608 this, but it seems a decent place to diagnose. */
3612 {
3617 }
3625 }
3626 }
3628 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3629 CALL. */
3631 static tree
3633 tree in_decl)
3634 {
3644 }
3646 /* Structure used to track the progress of find_parameter_packs_r. */
3647 struct find_parameter_pack_data
3648 {
3649 /* TREE_LIST that will contain all of the parameter packs found by
3650 the traversal. */
3653 /* Set of AST nodes that have been visited by the traversal. */
3656 /* True iff we're making a type pack expansion. */
3658 };
3660 /* Identifies all of the argument packs that occur in a template
3661 argument and appends them to the TREE_LIST inside DATA, which is a
3662 find_parameter_pack_data structure. This is a subroutine of
3663 make_pack_expansion and uses_parameter_packs. */
3664 static tree
3666 {
3672 /* Handle type aliases/typedefs. */
3674 {
3681 }
3683 /* Identify whether this is a parameter pack or not. */
3685 {
3693 /* FALLTHRU */
3695 /* If the placeholder appears in the decl-specifier-seq of a function
3696 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3697 is a pack expansion, the invented template parameter is a template
3698 parameter pack. */
3708 {
3709 /* We don't want to walk into the type of a PARM_DECL,
3710 because we don't want to see the type parameter pack. */
3713 }
3718 {
3719 /* We don't want to walk into the type of a variadic capture proxy,
3720 because we don't want to see the type parameter pack. */
3723 }
3725 {
3727 find_parameter_packs_r,
3730 }
3742 /* Not a parameter pack. */
3744 }
3747 {
3748 /* Add this parameter pack to the list. */
3750 }
3756 /* This switch statement will return immediately if we don't find a
3757 parameter pack. */
3759 {
3764 /* Check the template itself. */
3767 /* Check the template arguments. */
3781 /* Ignore the declaration of a capture proxy for a parameter pack. */
3789 /* Fall through. */
3834 {
3835 /* Look at explicit captures. */
3840 /* Since we defer implicit capture, look in the body as well. */
3846 }
3849 {
3850 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3851 type_pack_expansion_p to false so that any placeholders
3852 within the expression don't get marked as parameter packs. */
3860 }
3864 }
3867 }
3869 /* Determines if the expression or type T uses any parameter packs. */
3870 bool
3872 {
3881 }
3883 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3884 representation a base-class initializer into a parameter pack
3885 expansion. If all goes well, the resulting node will be an
3886 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3887 respectively. */
3888 tree
3890 {
3891 tree result;
3900 {
3901 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3902 class initializer. In this case, the TREE_PURPOSE will be a
3903 _TYPE node (representing the base class expansion we're
3904 initializing) and the TREE_VALUE will be a TREE_LIST
3905 containing the initialization arguments.
3907 The resulting expansion looks somewhat different from most
3908 expansions. Rather than returning just one _EXPANSION, we
3909 return a TREE_LIST whose TREE_PURPOSE is a
3910 TYPE_PACK_EXPANSION containing the bases that will be
3911 initialized. The TREE_VALUE will be identical to the
3912 original TREE_VALUE, which is a list of arguments that will
3913 be passed to each base. We do not introduce any new pack
3914 expansion nodes into the TREE_VALUE (although it is possible
3915 that some already exist), because the TREE_PURPOSE and
3916 TREE_VALUE all need to be expanded together with the same
3917 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3918 resulting TREE_PURPOSE will mention the parameter packs in
3919 both the bases and the arguments to the bases. */
3920 tree purpose;
3921 tree value;
3924 /* Determine which parameter packs will be used by the base
3925 class expansion. */
3934 {
3937 arg);
3940 }
3943 {
3944 /* Collect the sets of parameter packs used in each of the
3945 initialization arguments. */
3947 {
3948 /* Determine which parameter packs will be expanded in this
3949 argument. */
3952 }
3953 }
3957 /* Create the pack expansion type for the base type. */
3963 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3964 they will rarely be compared to anything. */
3968 }
3973 /* Build the PACK_EXPANSION_* node. */
3974 result = for_types
3979 {
3980 /* Propagate type and const-expression information. */
3983 /* Mark this read now, since the expansion might be length 0. */
3985 }
3986 else
3987 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3988 they will rarely be compared to anything. */
3991 /* Determine which parameter packs will be expanded. */
3998 /* Make sure we found some parameter packs. */
4000 {
4002 {
4005 else
4007 }
4009 }
4015 }
4017 /* Checks T for any "bare" parameter packs, which have not yet been
4018 expanded, and issues an error if any are found. This operation can
4019 only be done on full expressions or types (e.g., an expression
4020 statement, "if" condition, etc.), because we could have expressions like:
4022 foo(f(g(h(args)))...)
4024 where "args" is a parameter pack. check_for_bare_parameter_packs
4025 should not be called for the subexpressions args, h(args),
4026 g(h(args)), or f(g(h(args))), because we would produce erroneous
4027 error messages.
4029 Returns TRUE and emits an error if there were bare parameter packs,
4030 returns FALSE otherwise. */
4031 bool
4033 {
4040 /* A lambda might use a parameter pack from the containing context. */
4054 {
4058 {
4069 else
4074 else
4078 }
4081 }
4084 }
4086 /* Expand any parameter packs that occur in the template arguments in
4087 ARGS. */
4088 tree
4090 {
4099 /* First, determine if we need to expand anything, and the number of
4100 slots we'll need. */
4102 {
4107 {
4111 else
4113 }
4114 else
4115 {
4117 num_result_args++;
4118 }
4119 }
4121 /* If no expansion is necessary, we're done. */
4125 /* Expand arguments. */
4128 non_default_args_count =
4131 {
4134 {
4141 }
4142 else
4143 {
4146 }
4147 }
4151 }
4153 /* Checks if DECL shadows a template parameter.
4155 [temp.local]: A template-parameter shall not be redeclared within its
4156 scope (including nested scopes).
4158 Emits an error and returns TRUE if the DECL shadows a parameter,
4159 returns FALSE otherwise. */
4161 bool
4163 {
4164 tree olddecl;
4166 /* If we're not in a template, we can't possibly shadow a template
4167 parameter. */
4171 /* Figure out what we're shadowing. */
4175 /* If there's no previous binding for this name, we're not shadowing
4176 anything, let alone a template parameter. */
4180 /* If we're not shadowing a template parameter, we're done. Note
4181 that OLDDECL might be an OVERLOAD (or perhaps even an
4182 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4183 node. */
4187 /* We check for decl != olddecl to avoid bogus errors for using a
4188 name inside a class. We check TPFI to avoid duplicate errors for
4189 inline member templates. */
4195 /* Don't complain about the injected class name, as we've already
4196 complained about the class itself. */
4203 else
4208 }
4210 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4211 ORIG_LEVEL, DECL, and TYPE. */
4213 static tree
4217 tree decl,
4218 tree type)
4219 {
4230 }
4232 /* Find the canonical type parameter for the given template type
4233 parameter. Returns the canonical type parameter, which may be TYPE
4234 if no such parameter existed. */
4236 static tree
4238 {
4239 tree list;
4253 else
4254 {
4258 }
4259 }
4261 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4262 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4263 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4264 new one is created. */
4266 static tree
4268 tsubst_flags_t complain)
4269 {
4274 {
4293 /* Template template parameters need this. */
4295 {
4302 }
4303 }
4306 }
4308 /* Process information from new template parameter PARM and append it
4309 to the LIST being built. This new parameter is a non-type
4310 parameter iff IS_NON_TYPE is true. This new parameter is a
4311 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4312 is in PARM_LOC. */
4314 tree
4317 {
4326 {
4330 {
4334 else
4336 }
4339 }
4342 {
4348 {
4349 /* [temp.param]
4351 The top-level cv-qualifiers on the template-parameter are
4352 ignored when determining its type. */
4357 && !is_parameter_pack
4358 /* If we're in a nested template parameter list, the template
4359 template parameter could be a parameter pack. */
4361 {
4362 /* This template parameter is not a parameter pack, but it
4363 should be. Complain about "bare" parameter packs. */
4366 /* Recover by calling this a parameter pack. */
4368 }
4369 }
4371 /* A template parameter is not modifiable. */
4380 processing_template_decl,
4385 }
4386 else
4387 {
4388 tree t;
4392 {
4394 /* This is for distinguishing between real templates and template
4395 template parameters */
4399 }
4400 else
4401 {
4403 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4406 }
4413 processing_template_decl,
4417 }
4421 /* Build requirements for the type/template parameter.
4422 This must be done after SET_DECL_TEMPLATE_PARM_P or
4423 process_template_parm could fail. */
4431 /* Build the parameter node linking the parameter declaration,
4432 its default argument (if any), and its constraints (if any). */
4437 }
4439 /* The end of a template parameter list has been reached. Process the
4440 tree list into a parameter vector, converting each parameter into a more
4441 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4442 as PARM_DECLs. */
4444 tree
4446 {
4451 /* Pop the dummy parameter level and add the real one. */
4454 current_template_parms
4459 {
4463 }
4468 }
4470 // Explicitly indicate the end of the template parameter list. We assume
4471 // that the current template parameters have been constructed and/or
4472 // managed explicitly, as when creating new template template parameters
4473 // from a shorthand constraint.
4474 void
4476 {
4478 }
4480 /* end_template_decl is called after a template declaration is seen. */
4482 void
4484 {
4490 /* This matches the pushlevel in begin_template_parm_list. */
4495 }
4497 /* Takes a TREE_LIST representing a template parameter and convert it
4498 into an argument suitable to be passed to the type substitution
4499 functions. Note that If the TREE_LIST contains an error_mark
4500 node, the returned argument is error_mark_node. */
4502 tree
4504 {
4517 {
4521 {
4522 /* Turn this argument into a TYPE_ARGUMENT_PACK
4523 with a single element, which expands T. */
4532 }
4533 }
4534 else
4535 {
4539 {
4540 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4541 with a single element, which expands T. */
4551 }
4552 else
4554 }
4556 }
4558 /* Given a single level of template parameters (a TREE_VEC), return it
4559 as a set of template arguments. */
4561 static tree
4563 {
4573 }
4575 /* Given a set of template parameters, return them as a set of template
4576 arguments. The template parameters are represented as a TREE_VEC, in
4577 the form documented in cp-tree.h for template arguments. */
4579 static tree
4581 {
4582 tree header;
4587 /* If there is only one level of template parameters, we do not
4588 create a TREE_VEC of TREE_VECs. Instead, we return a single
4589 TREE_VEC containing the arguments. */
4594 {
4599 else
4601 }
4604 }
4606 /* Within the declaration of a template, return the currently active
4607 template parameters as an argument TREE_VEC. */
4609 static tree
4611 {
4613 }
4615 /* Update the declared TYPE by doing any lookups which were thought to be
4616 dependent, but are not now that we know the SCOPE of the declarator. */
4618 tree
4620 {
4631 /* Don't bother building up the args in this case. */
4633 {
4634 /* tsubst in the args corresponding to the template parameters,
4635 including auto if present. Most things will be unchanged, but
4636 make_typename_type and tsubst_qualified_id will resolve
4637 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4640 tree pushed;
4642 {
4646 }
4651 }
4657 {
4660 else
4662 }
4664 }
4666 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4667 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4668 the new template is a member template. */
4670 tree
4672 {
4680 }
4682 struct template_parm_data
4683 {
4684 /* The level of the template parameters we are currently
4685 processing. */
4688 /* The index of the specialization argument we are currently
4689 processing. */
4692 /* An array whose size is the number of template parameters. The
4693 elements are nonzero if the parameter has been used in any one
4694 of the arguments processed so far. */
4697 /* An array whose size is the number of template arguments. The
4698 elements are nonzero if the argument makes use of template
4699 parameters of this level. */
4701 };
4703 /* Subroutine of push_template_decl used to see if each template
4704 parameter in a partial specialization is used in the explicit
4705 argument list. If T is of the LEVEL given in DATA (which is
4706 treated as a template_parm_data*), then DATA->PARMS is marked
4707 appropriately. */
4709 static int
4711 {
4719 {
4722 }
4724 /* In C++17 the type of a non-type argument is a deduced context. */
4729 data,
4730 NULL,
4733 /* Return zero so that for_each_template_parm will continue the
4734 traversal of the tree; we want to mark *every* template parm. */
4736 }
4738 /* Process the partial specialization DECL. */
4740 static tree
4742 {
4749 tree inner_parms;
4750 tree inst;
4760 /* A concept cannot be specialized. */
4762 {
4765 }
4770 /* We check that each of the template parameters given in the
4771 partial specialization is used in the argument list to the
4772 specialization. For example:
4774 template <class T> struct S;
4775 template <class T> struct S<T*>;
4777 The second declaration is OK because `T*' uses the template
4778 parameter T, whereas
4780 template <class T> struct S<int>;
4782 is no good. Even trickier is:
4784 template <class T>
4785 struct S1
4786 {
4787 template <class U>
4788 struct S2;
4789 template <class U>
4790 struct S2<T>;
4791 };
4793 The S2<T> declaration is actually invalid; it is a
4794 full-specialization. Of course,
4796 template <class U>
4797 struct S2<T (*)(U)>;
4799 or some such would have been OK. */
4807 {
4812 NULL,
4814 }
4817 {
4818 /* One of the template parms was not used in a deduced context in the
4819 specialization. */
4821 {
4825 }
4829 }
4834 /* [temp.class.spec]
4836 The argument list of the specialization shall not be identical to
4837 the implicit argument list of the primary template. */
4838 tree main_args
4841 && (!flag_concepts
4844 {
4847 "any template arguments; to define the primary template, "
4849 else
4851 "template arguments and is not more constrained than "
4852 "the primary template; to define the primary template, "
4855 }
4857 /* A partial specialization that replaces multiple parameters of the
4858 primary template with a pack expansion is less specialized for those
4859 parameters. */
4861 {
4863 "primary template because it replaces multiple parameters "
4866 /* Avoid crash in process_partial_specialization. */
4868 }
4870 /* If we aren't in a dependent class, we can actually try deduction. */
4872 /* FIXME we should be able to handle a partial specialization of a
4873 partial instantiation, but currently we can't (c++/41727). */
4876 {
4880 maintmpl);
4881 }
4883 /* [temp.class.spec]
4885 A partially specialized non-type argument expression shall not
4886 involve template parameters of the partial specialization except
4887 when the argument expression is a simple identifier.
4889 The type of a template parameter corresponding to a specialized
4890 non-type argument shall not be dependent on a parameter of the
4891 specialization.
4893 Also, we verify that pack expansions only occur at the
4894 end of the argument list. */
4898 {
4905 {
4906 /* Extract the arguments from the argument pack. We'll be
4907 iterating over these in the following loop. */
4910 }
4913 {
4915 /* Get the Jth argument in the parameter pack. */
4919 {
4920 /* Pack expansions must come at the end of the
4921 argument list. */
4924 {
4928 else
4931 }
4932 }
4935 /* We only care about the pattern. */
4941 /* This next two lines are the `argument expression is not just a
4942 simple identifier' condition and also the `specialized
4943 non-type argument' bit. */
4947 {
4951 arg);
4952 else
4953 {
4954 /* Look at the corresponding template parameter,
4955 marking which template parameters its type depends
4956 upon. */
4960 {
4961 /* We haven't yet initialized TPD2. Do so now. */
4963 /* The number of parameters here is the number in the
4964 main template, which, as checked in the assertion
4965 above, is NARGS. */
4969 }
4971 /* Mark the template parameters. But this time, we're
4972 looking for the template parameters of the main
4973 template, not in the specialization. */
4980 NULL,
4984 {
4985 /* The type depended on some template parameters.
4986 If they are fully specialized in the
4987 specialization, that's OK. */
4996 "type %qT of template argument %qE depends "
4998 "type %qT of template argument %qE depends "
5000 type,
5001 arg);
5002 }
5003 }
5004 }
5005 }
5006 }
5008 /* We should only get here once. */
5012 // Build the template decl.
5021 /* Give template template parms a DECL_CONTEXT of the template
5022 for which they are a parameter. */
5024 {
5028 }
5031 /* We didn't register this in check_explicit_specialization so we could
5032 wait until the constraints were set. */
5034 else
5044 {
5050 {
5058 "declaration of %qD ambiguates earlier template "
5062 "partial specialization of %qD after instantiation "
5064 }
5065 }
5068 }
5070 /* PARM is a template parameter of some form; return the corresponding
5071 TEMPLATE_PARM_INDEX. */
5073 static tree
5075 {
5088 }
5090 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5091 parameter packs used by the template parameter PARM. */
5093 static void
5095 {
5096 /* A type parm can't refer to another parm. */
5100 {
5104 }
5111 }
5113 /* PARM is a template parameter pack. Return any parameter packs used in
5114 its type or the type of any of its template parameters. If there are
5115 any such packs, it will be instantiated into a fixed template parameter
5116 list by partial instantiation rather than be fully deduced. */
5118 tree
5120 {
5121 /* This can only be true in a member template. */
5124 /* This can only be true for a parameter pack. */
5127 /* A type parm can't refer to another parm. */
5141 }
5143 /* Check that a template declaration's use of default arguments and
5144 parameter packs is not invalid. Here, PARMS are the template
5145 parameters. IS_PRIMARY is true if DECL is the thing declared by
5146 a primary template. IS_PARTIAL is true if DECL is a partial
5147 specialization.
5149 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5150 function template declaration or a friend class template
5151 declaration. In the function case, 1 indicates a declaration, 2
5152 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5153 emitted for extraneous default arguments.
5155 Returns TRUE if there were no errors found, FALSE otherwise. */
5157 bool
5160 {
5163 tree parm_level;
5166 /* [temp.param]
5168 A default template-argument shall not be specified in a
5169 function template declaration or a function template definition, nor
5170 in the template-parameter-list of the definition of a member of a
5171 class template. */
5175 /* You can't have a function template declaration in a local
5176 scope, nor you can you define a member of a class template in a
5177 local scope. */
5185 /* A lambda doesn't have an explicit declaration; don't complain
5186 about the parms of the enclosing class. */
5193 /* If this is either a friend defined in the scope of the class
5194 or a member function. */
5200 /* And, if it was a member function, it really was defined in
5201 the scope of the class. */
5204 /* We already checked these parameters when the template was
5205 declared, so there's no need to do it again now. This function
5206 was defined in class scope, but we're processing its body now
5207 that the class is complete. */
5210 /* Core issue 226 (C++0x only): the following only applies to class
5211 templates. */
5214 {
5215 /* [temp.param]
5217 If a template-parameter has a default template-argument, all
5218 subsequent template-parameters shall have a default
5219 template-argument supplied. */
5221 {
5228 {
5238 {
5240 /* For better subsequent error-recovery, we indicate that
5241 there should have been a default argument. */
5244 }
5246 && !is_friend_decl
5247 /* Don't complain about an enclosing partial
5248 specialization. */
5253 /* A fixed parameter pack will be partially
5254 instantiated into a fixed length list. */
5256 {
5257 /* A primary class template can only have one
5258 parameter pack, at the end of the template
5259 parameter list. */
5267 }
5268 }
5269 }
5270 }
5273 || is_partial
5274 || !is_primary
5276 /* For an ordinary class template, default template arguments are
5277 allowed at the innermost level, e.g.:
5278 template <class T = int>
5279 struct S {};
5280 but, in a partial specialization, they're not allowed even
5281 there, as we have in [temp.class.spec]:
5283 The template parameter list of a specialization shall not
5284 contain default template argument values.
5286 So, for a partial specialization, or for a function template
5287 (in C++98/C++03), we look at all of them. */
5288 ;
5289 else
5290 /* But, for a primary class template that is not a partial
5291 specialization we look at all template parameters except the
5292 innermost ones. */
5295 /* Figure out what error message to issue. */
5310 else
5311 /* Per [temp.param]/9, "A default template-argument shall not be
5312 specified in the template-parameter-lists of the definition of
5313 a member of a class template that appears outside of the member's
5314 class.", thus if we aren't handling a member of a class template
5315 there is no need to examine the parameters. */
5319 /* If we're inside a class definition, there's no need to
5320 examine the parameters to the class itself. On the one
5321 hand, they will be checked when the class is defined, and,
5322 on the other, default arguments are valid in things like:
5323 template <class T = double>
5324 struct S { template <class U> void f(U); };
5325 Here the default argument for `S' has no bearing on the
5326 declaration of `f'. */
5328 else
5329 /* Check everything. */
5335 {
5342 {
5347 {
5349 {
5356 }
5358 /* Clear out the default argument so that we are not
5359 confused later. */
5361 }
5362 }
5364 /* At this point, if we're still interested in issuing messages,
5365 they must apply to classes surrounding the object declared. */
5369 }
5372 }
5374 /* Worker for push_template_decl_real, called via
5375 for_each_template_parm. DATA is really an int, indicating the
5376 level of the parameters we are interested in. If T is a template
5377 parameter of that level, return nonzero. */
5379 static int
5381 {
5387 else
5390 }
5392 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5393 DATA is really an int, indicating the innermost outer level of parameters.
5394 If T is a template parameter of that level or further out, return
5395 nonzero. */
5397 static int
5399 {
5405 else
5408 }
5410 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5411 parameters given by current_template_args, or reuses a
5412 previously existing one, if appropriate. Returns the DECL, or an
5413 equivalent one, if it is replaced via a call to duplicate_decls.
5415 If IS_FRIEND is true, DECL is a friend declaration. */
5417 tree
5419 {
5420 tree tmpl;
5421 tree args;
5422 tree info;
5423 tree ctx;
5427 /* True if the template is a member template, in the sense of
5428 [temp.mem]. */
5434 /* See if this is a partial specialization. */
5447 /* For a friend, we want the context of the friend, not
5448 the type of which it is a friend. */
5452 /* In the case of a virtual function, we want the class in which
5453 it is defined. */
5455 else
5456 /* Otherwise, if we're currently defining some class, the DECL
5457 is assumed to be a member of the class. */
5466 /* See if this is a primary template. */
5469 /* A friend template that specifies a class context, i.e.
5470 template <typename T> friend void A<T>::f();
5471 is not primary. */
5476 else
5480 {
5487 {
5490 }
5492 {
5494 {
5497 }
5499 {
5500 /* [temp.mem]
5502 A destructor shall not be a member template. */
5505 }
5512 {
5513 /* [basic.stc.dynamic.allocation]
5515 An allocation function can be a function
5516 template. ... Template allocation functions shall
5517 have two or more parameters. */
5520 }
5521 }
5524 {
5525 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5528 {
5534 }
5535 }
5538 /* alias-declaration */
5542 else
5543 {
5546 }
5547 }
5549 /* Check to see that the rules regarding the use of default
5550 arguments are not being violated. We check args for a friend
5551 functions when we know whether it's a definition, introducing
5552 declaration or re-declaration. */
5557 /* Ensure that there are no parameter packs in the type of this
5558 declaration that have not been expanded. */
5560 {
5561 /* Check each of the arguments individually to see if there are
5562 any bare parameter packs. */
5568 {
5571 {
5572 /* This is a PARM_DECL that contains unexpanded parameter
5573 packs. We have already complained about this in the
5574 check_for_bare_parameter_packs call, so just replace
5575 these types with ERROR_MARK_NODE. */
5578 }
5582 }
5584 /* Check for bare parameter packs in the return type and the
5585 exception specifiers. */
5587 /* Errors were already issued, set return type to int
5588 as the frontend doesn't expect error_mark_node as
5589 the return type. */
5593 }
5598 {
5601 }
5614 {
5619 /* If DECL is a TYPE_DECL for a class-template, then there won't
5620 be DECL_LANG_SPECIFIC. The information equivalent to
5621 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5625 {
5626 /* Since a template declaration already existed for this
5627 class-type, we must be redeclaring it here. Make sure
5628 that the redeclaration is valid. */
5630 current_template_parms,
5632 /* We don't need to create a new TEMPLATE_DECL; just use the
5633 one we already had. */
5635 }
5636 else
5637 {
5639 member_template_p);
5644 {
5645 /* A specialization of a member template of a template
5646 class. */
5650 }
5651 }
5652 }
5653 else
5654 {
5660 {
5663 }
5671 {
5672 tree new_tmpl;
5674 /* The declaration is a specialization of a member
5675 template, declared outside the class. Therefore, the
5676 innermost template arguments will be NULL, so we
5677 replace them with the arguments determined by the
5678 earlier call to check_explicit_specialization. */
5681 new_tmpl
5683 member_template_p);
5693 args,
5696 }
5698 /* Make sure the template headers we got make sense. */
5703 {
5708 }
5709 else
5711 {
5716 {
5720 else
5724 /* Avoid crash in import_export_decl. */
5727 }
5732 /* Can happen in erroneous input. */
5734 else
5736 }
5738 /* Check that the parms are used in the appropriate qualifying scopes
5739 in the declarator. */
5743 {
5749 /* Avoid crash in import_export_decl. */
5752 }
5753 }
5758 /* Push template declarations for global functions and types. Note
5759 that we do not try to push a global template friend declared in a
5760 template class; such a thing may well depend on the template
5761 parameters of the class. */
5764 {
5769 /* Hide template friend classes that haven't been declared yet. */
5771 {
5774 }
5775 }
5778 {
5783 /* Give template template parms a DECL_CONTEXT of the template
5784 for which they are a parameter. */
5787 {
5791 }
5797 }
5799 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5800 back to its most general template. If TMPL is a specialization,
5801 ARGS may only have the innermost set of arguments. Add the missing
5802 argument levels if necessary. */
5810 else
5811 {
5816 }
5819 && !is_friend
5822 /* Set DECL_COMDAT on template instantiations; if we force
5823 them to be emitted by explicit instantiation or -frepo,
5824 mark_needed will tell cgraph to do the right thing. */
5828 }
5830 tree
5832 {
5834 }
5836 /* FN is an inheriting constructor that inherits from the constructor
5837 template INHERITED; turn FN into a constructor template with a matching
5838 template header. */
5840 tree
5842 {
5843 tree inner_parms
5846 tree parms
5857 }
5859 /* Called when a class template TYPE is redeclared with the indicated
5860 template PARMS, e.g.:
5862 template <class T> struct S;
5863 template <class T> struct S {}; */
5865 bool
5867 {
5868 tree tmpl;
5869 tree tmpl_parms;
5873 {
5876 }
5880 /* The type is nested in some template class. Nothing to worry
5881 about here; there are no new template parameters for the nested
5882 type. */
5886 {
5888 tmpl);
5890 }
5896 {
5906 }
5909 {
5910 tree tmpl_parm;
5911 tree parm;
5912 tree tmpl_default;
5913 tree parm_default;
5927 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5928 TEMPLATE_DECL. */
5938 {
5942 }
5945 {
5946 /* We have in [temp.param]:
5948 A template-parameter may not be given default arguments
5949 by two different declarations in the same scope. */
5954 }
5957 /* Update the previous template parameters (which are the ones
5958 that will really count) with the new default value. */
5961 /* Update the new parameters, too; they'll be used as the
5962 parameters for any members. */
5965 /* Give each template template parm in this redeclaration a
5966 DECL_CONTEXT of the template for which they are a parameter. */
5968 {
5971 }
5975 }
5977 // Cannot redeclare a class template with a different set of constraints.
5979 {
5984 }
5987 }
5989 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5990 to be used when the caller has already checked
5991 (processing_template_decl
5992 && !instantiation_dependent_expression_p (expr)
5993 && potential_constant_expression (expr))
5994 and cleared processing_template_decl. */
5996 tree
5998 {
6001 complain,
6005 }
6007 /* Simplify EXPR if it is a non-dependent expression. Returns the
6008 (possibly simplified) expression. */
6010 tree
6012 {
6016 /* If we're in a template, but EXPR isn't value dependent, simplify
6017 it. We're supposed to treat:
6019 template <typename T> void f(T[1 + 1]);
6020 template <typename T> void f(T[2]);
6022 as two declarations of the same function, for example. */
6025 {
6026 processing_template_decl_sentinel s;
6028 }
6030 }
6032 tree
6034 {
6036 }
6038 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6039 an uninstantiated expression. */
6041 tree
6043 {
6047 {
6050 else
6051 {
6052 processing_template_decl_sentinel s;
6054 }
6055 }
6057 }
6059 /* True iff T is a specialization of a variable template. */
6061 bool
6063 {
6068 }
6070 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6071 template declaration, or a TYPE_DECL for an alias declaration. */
6073 bool
6075 {
6083 }
6085 /* Return TRUE iff T is a specialization of an alias template. */
6087 bool
6089 {
6090 /* It's an alias template specialization if it's an alias and its
6091 TYPE_NAME is a specialization of a primary template. */
6097 }
6099 /* An alias template is complex from a SFINAE perspective if a template-id
6100 using that alias can be ill-formed when the expansion is not, as with
6101 the void_t template. We determine this by checking whether the
6102 expansion for the alias template uses all its template parameters. */
6104 struct uses_all_template_parms_data
6105 {
6108 };
6110 static int
6112 {
6120 }
6122 static bool
6124 {
6139 }
6141 /* Return TRUE iff T is a specialization of a complex alias template with
6142 dependent template-arguments. */
6144 bool
6146 {
6159 }
6161 /* Return the number of innermost template parameters in TMPL. */
6163 static int
6165 {
6168 }
6170 /* Return either TMPL or another template that it is equivalent to under DR
6171 1286: An alias that just changes the name of a template is equivalent to
6172 the other template. */
6174 static tree
6176 {
6179 {
6180 /* Determine if the alias is equivalent to an underlying template. */
6192 tree alias_args = INNERMOST_TEMPLATE_ARGS
6197 /* Alias is equivalent. Strip it and repeat. */
6199 }
6202 }
6204 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6205 must be a reference-to-function or a pointer-to-function type, as specified
6206 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6207 and check that the resulting function has external linkage. */
6209 static tree
6211 tsubst_flags_t complain)
6212 {
6215 linkage_kind linkage;
6230 /* [temp.arg.nontype]/1
6232 A template-argument for a non-type, non-template template-parameter
6233 shall be one of:
6234 [...]
6235 -- the address of an object or function with external [C++11: or
6236 internal] linkage. */
6239 {
6241 {
6247 else
6250 }
6252 }
6256 {
6258 {
6263 else
6267 }
6269 }
6271 accept:
6273 {
6276 else
6278 }
6283 }
6285 /* Subroutine of convert_nontype_argument.
6286 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6287 Emit an error otherwise. */
6289 static bool
6291 tsubst_flags_t complain)
6292 {
6309 {
6314 else
6316 }
6318 }
6320 /* Returns TRUE iff the address of OP is value-dependent.
6322 14.6.2.4 [temp.dep.temp]:
6323 A non-integral non-type template-argument is dependent if its type is
6324 dependent or it has either of the following forms
6325 qualified-id
6326 & qualified-id
6327 and contains a nested-name-specifier which specifies a class-name that
6328 names a dependent type.
6330 We generalize this to just say that the address of a member of a
6331 dependent class is value-dependent; the above doesn't cover the
6332 address of a static data member named with an unqualified-id. */
6334 static bool
6336 {
6337 /* We could use get_inner_reference here, but there's no need;
6338 this is only relevant for template non-type arguments, which
6339 can only be expressed as &id-expression. */
6341 {
6345 }
6348 }
6350 /* The next set of functions are used for providing helpful explanatory
6351 diagnostics for failed overload resolution. Their messages should be
6352 indented by two spaces for consistency with the messages in
6353 call.c */
6355 static int
6357 {
6359 }
6361 /* Other failure functions should call this one, to provide a single function
6362 for setting a breakpoint on. */
6364 static int
6366 {
6368 }
6370 static int
6372 {
6377 }
6379 static int
6381 {
6387 }
6389 static int
6391 {
6395 }
6397 static int
6399 {
6402 " template parameter %qD is not a parameter pack, but "
6406 }
6408 static int
6410 {
6413 " template argument %qE does not match "
6417 }
6419 static int
6421 {
6425 }
6427 static int
6429 {
6435 }
6437 static int
6439 {
6441 {
6446 else
6448 " deduced conflicting values for non-type parameter "
6450 }
6452 }
6454 static int
6456 {
6459 " variable-sized array type %qT is not "
6461 arg);
6463 }
6465 static int
6467 {
6471 arg);
6473 }
6475 static int
6477 {
6479 {
6485 else
6490 }
6492 }
6494 static int
6496 {
6498 }
6500 static int
6503 {
6505 }
6507 static int
6510 {
6516 }
6518 static int
6521 {
6524 {
6532 }
6534 }
6536 static int
6538 {
6541 " template parameters of a template template argument are "
6544 }
6546 static int
6548 {
6554 }
6556 static int
6558 {
6563 }
6565 /* Attempt to convert the non-type template parameter EXPR to the
6566 indicated TYPE. If the conversion is successful, return the
6567 converted value. If the conversion is unsuccessful, return
6568 NULL_TREE if we issued an error message, or error_mark_node if we
6569 did not. We issue error messages for out-and-out bad template
6570 parameters, but not simply because the conversion failed, since we
6571 might be just trying to do argument deduction. Both TYPE and EXPR
6572 must be non-dependent.
6574 The conversion follows the special rules described in
6575 [temp.arg.nontype], and it is much more strict than an implicit
6576 conversion.
6578 This function is called twice for each template argument (see
6579 lookup_template_class for a more accurate description of this
6580 problem). This means that we need to handle expressions which
6581 are not valid in a C++ source, but can be created from the
6582 first call (for instance, casts to perform conversions). These
6583 hacks can go away after we fix the double coercion problem. */
6585 static tree
6587 {
6588 tree expr_type;
6592 /* Detect immediately string literals as invalid non-type argument.
6593 This special-case is not needed for correctness (we would easily
6594 catch this later), but only to provide better diagnostic for this
6595 common user mistake. As suggested by DR 100, we do not mention
6596 linkage issues in the diagnostic as this is not the point. */
6597 /* FIXME we're making this OK. */
6599 {
6605 }
6607 /* Add the ADDR_EXPR now for the benefit of
6608 value_dependent_expression_p. */
6611 {
6615 }
6617 /* If we are in a template, EXPR may be non-dependent, but still
6618 have a syntactic, rather than semantic, form. For example, EXPR
6619 might be a SCOPE_REF, rather than the VAR_DECL to which the
6620 SCOPE_REF refers. Preserving the qualifying scope is necessary
6621 so that access checking can be performed when the template is
6622 instantiated -- but here we need the resolved form so that we can
6623 convert the argument. */
6635 /* If the argument is non-dependent, perform any conversions in
6636 non-dependent context as well. */
6644 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6645 to a non-type argument of "nullptr". */
6649 /* In C++11, integral or enumeration non-type template arguments can be
6650 arbitrary constant expressions. Pointer and pointer to
6651 member arguments can be general constant expressions that evaluate
6652 to a null value, but otherwise still need to be of a specific form. */
6654 {
6656 /* A PTRMEM_CST is already constant, and a valid template
6657 argument for a parameter of pointer to member type, we just want
6658 to leave it in that form rather than lower it to a
6662 {
6663 /* C++17: A template-argument for a non-type template-parameter shall
6664 be a converted constant expression (8.20) of the type of the
6665 template-parameter. */
6671 }
6673 {
6678 }
6679 }
6683 else
6686 /* HACK: Due to double coercion, we can get a
6687 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6688 which is the tree that we built on the first call (see
6689 below when coercing to reference to object or to reference to
6690 function). We just strip everything and get to the arg.
6691 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6692 for examples. */
6694 {
6700 {
6701 /* ??? Maybe we could use convert_from_reference here, but we
6702 would need to relax its constraints because the NOP_EXPR
6703 could actually change the type to something more cv-qualified,
6704 and this is not folded by convert_from_reference. */
6709 && (same_type_ignoring_top_level_qualifiers_p
6712 {
6715 }
6716 }
6717 }
6719 /* [temp.arg.nontype]/5, bullet 1
6721 For a non-type template-parameter of integral or enumeration type,
6722 integral promotions (_conv.prom_) and integral conversions
6723 (_conv.integral_) are applied. */
6725 {
6727 {
6732 }
6737 /* Notice that there are constant expressions like '4 % 0' which
6738 do not fold into integer constants. */
6741 {
6743 {
6747 else
6753 /* else cxx_constant_value complained but gave us
6754 a real constant, so go ahead. */
6756 {
6757 /* Some assemble time constant expressions like
6758 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6759 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6760 as we can emit them into .rodata initializers of
6761 variables, yet they can't fold into an INTEGER_CST at
6762 compile time. Refuse them here. */
6767 }
6768 }
6769 else
6771 }
6773 /* Avoid typedef problems. */
6776 }
6777 /* [temp.arg.nontype]/5, bullet 2
6779 For a non-type template-parameter of type pointer to object,
6780 qualification conversions (_conv.qual_) and the array-to-pointer
6781 conversion (_conv.array_) are applied. */
6783 {
6786 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6787 decay_conversion or an explicit cast. If it's a problematic cast,
6788 we'll complain about it below. */
6790 {
6795 {
6798 }
6799 }
6801 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6803 A template-argument for a non-type, non-template template-parameter
6804 shall be one of: [...]
6806 -- the name of a non-type template-parameter;
6807 -- the address of an object or function with external linkage, [...]
6808 expressed as "& id-expression" where the & is optional if the name
6809 refers to a function or array, or if the corresponding
6810 template-parameter is a reference.
6812 Here, we do not care about functions, as they are invalid anyway
6813 for a parameter of type pointer-to-object. */
6816 /* Non-type template parameters are OK. */
6817 ;
6821 {
6823 {
6826 "because %qD is a variable, not the address of "
6829 }
6831 {
6837 }
6838 /* Other values, like integer constants, might be valid
6839 non-type arguments of some other type. */
6841 }
6842 else
6843 {
6847 {
6852 }
6854 {
6860 }
6863 {
6868 }
6869 /* C++17: For a non-type template-parameter of reference or pointer
6870 type, the value of the constant expression shall not refer to (or
6871 for a pointer type, shall not be the address of):
6872 * a subobject (4.5),
6873 * a temporary object (15.2),
6874 * a string literal (5.13.5),
6875 * the result of a typeid expression (8.2.8), or
6876 * a predefined __func__ variable (11.4.1). */
6878 {
6881 decl);
6883 }
6887 {
6892 }
6894 {
6898 decl);
6900 }
6901 }
6908 }
6909 /* [temp.arg.nontype]/5, bullet 3
6911 For a non-type template-parameter of type reference to object, no
6912 conversions apply. The type referred to by the reference may be more
6913 cv-qualified than the (otherwise identical) type of the
6914 template-argument. The template-parameter is bound directly to the
6915 template-argument, which must be an lvalue. */
6917 {
6919 expr_type))
6923 {
6928 }
6931 {
6936 }
6938 /* [temp.arg.nontype]/1
6940 A template-argument for a non-type, non-template template-parameter
6941 shall be one of: [...]
6943 -- the address of an object or function with external linkage. */
6946 {
6949 {
6952 "because a reference variable does not have a constant "
6955 }
6956 }
6960 /* OK, dependent reference. We don't want to ask whether a DECL is
6962 else
6963 {
6965 {
6971 }
6973 /* DR 1155 allows internal linkage in C++11 and up. */
6976 {
6982 }
6985 }
6989 }
6990 /* [temp.arg.nontype]/5, bullet 4
6992 For a non-type template-parameter of type pointer to function, only
6993 the function-to-pointer conversion (_conv.func_) is applied. If the
6994 template-argument represents a set of overloaded functions (or a
6995 pointer to such), the matching function is selected from the set
6996 (_over.over_). */
6998 {
6999 /* If the argument is a template-id, we might not have enough
7000 context information to decay the pointer. */
7002 {
7006 }
7009 /* Null pointer values are OK in C++11. */
7015 }
7016 /* [temp.arg.nontype]/5, bullet 5
7018 For a non-type template-parameter of type reference to function, no
7019 conversions apply. If the template-argument represents a set of
7020 overloaded functions, the matching function is selected from the set
7021 (_over.over_). */
7023 {
7025 {
7027 {
7032 }
7034 }
7039 }
7040 /* [temp.arg.nontype]/5, bullet 6
7042 For a non-type template-parameter of type pointer to member function,
7043 no conversions apply. If the template-argument represents a set of
7044 overloaded member functions, the matching member function is selected
7045 from the set (_over.over_). */
7047 {
7052 /* [temp.arg.nontype] bullet 1 says the pointer to member
7053 expression must be a pointer-to-member constant. */
7058 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7059 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7062 }
7063 /* [temp.arg.nontype]/5, bullet 7
7065 For a non-type template-parameter of type pointer to data member,
7066 qualification conversions (_conv.qual_) are applied. */
7068 {
7069 /* [temp.arg.nontype] bullet 1 says the pointer to member
7070 expression must be a pointer-to-member constant. */
7078 }
7080 {
7082 {
7087 }
7089 }
7090 /* A template non-type parameter must be one of the above. */
7091 else
7094 /* Sanity check: did we actually convert the argument to the
7095 right type? */
7099 }
7101 /* Subroutine of coerce_template_template_parms, which returns 1 if
7102 PARM_PARM and ARG_PARM match using the rule for the template
7103 parameters of template template parameters. Both PARM and ARG are
7104 template parameters; the rest of the arguments are the same as for
7105 coerce_template_template_parms.
7106 */
7107 static int
7109 tree arg,
7110 tsubst_flags_t complain,
7111 tree in_decl,
7112 tree outer_args)
7113 {
7122 {
7124 /* We encounter instantiations of templates like
7125 template <template <template <class> class> class TT>
7126 class C; */
7127 {
7134 }
7135 /* Fall through. */
7140 /* Argument is a parameter pack but parameter is not. */
7145 /* The tsubst call is used to handle cases such as
7147 template <int> class C {};
7148 template <class T, template <T> class TT> class D {};
7149 D<int, C> d;
7151 i.e. the parameter list of TT depends on earlier parameters. */
7153 {
7158 }
7162 /* Argument is a parameter pack but parameter is not. */
7169 }
7172 }
7174 /* Coerce template argument list ARGLIST for use with template
7175 template-parameter TEMPL. */
7177 static tree
7179 tsubst_flags_t complain)
7180 {
7181 /* Consider an example where a template template parameter declared as
7183 template <class T, class U = std::allocator<T> > class TT
7185 The template parameter level of T and U are one level larger than
7186 of TT. To proper process the default argument of U, say when an
7187 instantiation `TT<int>' is seen, we need to build the full
7188 arguments containing {int} as the innermost level. Outer levels,
7189 available when not appearing as default template argument, can be
7190 obtained from the arguments of the enclosing template.
7192 Suppose that TT is later substituted with std::vector. The above
7193 instantiation is `TT<int, std::allocator<T> >' with TT at
7194 level 1, and T at level 2, while the template arguments at level 1
7195 becomes {std::vector} and the inner level 2 is {int}. */
7199 {
7201 /* We want arguments for the partial specialization, not arguments for
7202 the primary template. */
7204 else
7206 }
7208 {
7209 /* This is an argument of the current template, so we haven't set
7210 DECL_CONTEXT yet. */
7211 tree relevant_template_parms;
7213 /* Parameter levels that are greater than the level of the given
7214 template template parm are irrelevant. */
7221 }
7228 complain,
7231 }
7233 /* A cache of template template parameters with match-all default
7234 arguments. */
7236 static void
7238 {
7242 }
7243 static tree
7245 {
7250 }
7252 /* T is a bound template template-parameter. Copy its arguments into default
7253 arguments of the template template-parameter's template parameters. */
7255 static tree
7257 {
7280 {
7283 {
7286 }
7287 }
7291 }
7293 /* ARG is a bound potential template template-argument, and PARGS is a list
7294 of arguments for the corresponding template template-parameter. Adjust
7295 PARGS as appropriate for application to ARG's template, and if ARG is a
7296 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7297 arguments to the template template parameter. */
7299 static tree
7301 {
7305 {
7306 /* When comparing two template template-parameters in partial ordering,
7307 rewrite the one currently being used as an argument to have default
7308 arguments for all parameters. */
7314 }
7315 else
7316 {
7317 tree aparms
7322 }
7325 }
7327 /* Subroutine of unify for the case when PARM is a
7328 BOUND_TEMPLATE_TEMPLATE_PARM. */
7330 static int
7333 {
7337 /* The template template parm might be variadic and the argument
7338 not, so flatten both argument lists. */
7343 {
7344 /* In keeping with P0522R0, adjust P's template arguments
7345 to apply to A's template; then flatten it again. */
7354 /* If the P0522 adjustment eliminated a pack expansion, deduce
7355 empty packs. */
7361 }
7362 else
7363 {
7364 /* Deduce arguments T, i from TT<T> or TT<i>.
7365 We check each element of PARMVEC and ARGVEC individually
7366 rather than the whole TREE_VEC since they can have
7367 different number of elements, which is allowed under N2555. */
7371 /* Check if the parameters end in a pack, making them
7372 variadic. */
7379 /* If the template argument list of P contains a pack
7380 expansion that is not the last template argument, the
7381 entire template argument list is a non-deduced
7382 context. */
7400 DEDUCE_EXACT,
7403 }
7406 }
7408 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7409 template template parameters. Both PARM_PARMS and ARG_PARMS are
7410 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7411 or PARM_DECL.
7413 Consider the example:
7414 template <class T> class A;
7415 template<template <class U> class TT> class B;
7417 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7418 the parameters to A, and OUTER_ARGS contains A. */
7420 static int
7422 tree arg_parms,
7423 tsubst_flags_t complain,
7424 tree in_decl,
7425 tree outer_args)
7426 {
7438 {
7439 /* P0522R0: A template template-parameter P is at least as specialized as
7440 a template template-argument A if, given the following rewrite to two
7441 function templates, the function template corresponding to P is at
7442 least as specialized as the function template corresponding to A
7443 according to the partial ordering rules for function templates
7444 ([temp.func.order]). Given an invented class template X with the
7445 template parameter list of A (including default arguments):
7447 * Each of the two function templates has the same template parameters,
7448 respectively, as P or A.
7450 * Each function template has a single function parameter whose type is
7451 a specialization of X with template arguments corresponding to the
7452 template parameters from the respective function template where, for
7453 each template parameter PP in the template parameter list of the
7454 function template, a corresponding template argument AA is formed. If
7455 PP declares a parameter pack, then AA is the pack expansion
7456 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7458 If the rewrite produces an invalid type, then P is not at least as
7459 specialized as A. */
7461 /* So coerce P's args to apply to A's parms, and then deduce between A's
7462 args and the converted args. If that succeeds, A is at least as
7463 specialized as P, so they match.*/
7470 {
7476 }
7477 }
7479 /* Determine whether we have a parameter pack at the end of the
7480 template template parameter's template parameter list. */
7482 {
7489 {
7503 }
7504 }
7510 /* Check all of the template parameters except the parameter pack at
7511 the end (if any). */
7513 {
7522 outer_args))
7525 }
7528 {
7529 /* Check each of the template parameters in the template
7530 argument against the template parameter pack at the end of
7531 the template template parameter. */
7538 {
7545 outer_args))
7547 }
7548 }
7551 }
7553 /* Verifies that the deduced template arguments (in TARGS) for the
7554 template template parameters (in TPARMS) represent valid bindings,
7555 by comparing the template parameter list of each template argument
7556 to the template parameter list of its corresponding template
7557 template parameter, in accordance with DR150. This
7558 routine can only be called after all template arguments have been
7559 deduced. It will return TRUE if all of the template template
7560 parameter bindings are okay, FALSE otherwise. */
7561 bool
7563 {
7567 /* We're dealing with template parms in this process. */
7573 {
7578 {
7583 {
7584 /* Look inside the argument pack. */
7587 }
7590 {
7594 /* Extract the next argument from the argument
7595 pack. */
7599 /* Look at the pattern of the pack expansion. */
7602 /* Extract the template parameters from the template
7603 argument. */
7609 /* Verify that we can coerce the template template
7610 parameters from the template argument to the template
7611 parameter. This requires an exact match. */
7613 && !coerce_template_template_parms
7615 targ_parms,
7616 tf_none,
7617 tparm,
7618 targs))
7619 {
7622 }
7623 }
7624 }
7625 }
7627 out:
7631 }
7633 /* Since type attributes aren't mangled, we need to strip them from
7634 template type arguments. */
7636 static tree
7638 {
7648 }
7650 /* And from inside dependent non-type arguments like sizeof(Type). */
7652 static tree
7654 {
7664 }
7666 // A template declaration can be substituted for a constrained
7667 // template template parameter only when the argument is more
7668 // constrained than the parameter.
7669 static bool
7671 {
7674 /* For now, allow constrained template template arguments
7675 and unconstrained template template parameters. */
7681 // If the template parameter is constrained, we need to rewrite its
7682 // constraints in terms of the ARG's template parameters. This ensures
7683 // that all of the template parameter types will have the same depth.
7684 //
7685 // Note that this is only valid when coerce_template_template_parm is
7686 // true for the innermost template parameters of PARM and ARG. In other
7687 // words, because coercion is successful, this conversion will be valid.
7689 {
7696 }
7699 }
7701 // Convert a placeholder argument into a binding to the original
7702 // parameter. The original parameter is saved as the TREE_TYPE of
7703 // ARG.
7706 {
7709 }
7711 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7712 because one of them is dependent. But we need to represent the
7713 conversion for the benefit of cp_tree_equal. */
7715 static tree
7717 {
7718 /* Auto parms get no conversion. */
7721 /* We don't need or want to add this conversion now if we're going to use the
7722 argument for deduction. */
7734 }
7736 /* Convert the indicated template ARG as necessary to match the
7737 indicated template PARM. Returns the converted ARG, or
7738 error_mark_node if the conversion was unsuccessful. Error and
7739 warning messages are issued under control of COMPLAIN. This
7740 conversion is for the Ith parameter in the parameter list. ARGS is
7741 the full set of template arguments deduced so far. */
7743 static tree
7745 tree arg,
7746 tree args,
7747 tsubst_flags_t complain,
7749 tree in_decl)
7750 {
7751 tree orig_arg;
7752 tree val;
7758 /* Trivially convert placeholders. */
7767 {
7768 /* The template argument was the name of some
7769 member function. That's usually
7770 invalid, but static members are OK. In any
7771 case, grab the underlying fields/functions
7772 and issue an error later if required. */
7775 }
7783 /* When determining whether an argument pack expansion is a template,
7784 look at the pattern. */
7788 /* Deal with an injected-class-name used as a template template arg. */
7790 {
7793 {
7803 }
7804 }
7806 is_tmpl_type =
7822 {
7824 {
7828 }
7831 "to refer to a type member of a template parameter, "
7836 typename_type,
7837 complain);
7840 }
7842 {
7844 {
7846 {
7858 else
7861 }
7862 }
7864 }
7866 {
7868 {
7875 else
7878 }
7880 }
7883 /* We already did the appropriate conversion when packing args. */
7886 {
7888 {
7890 /* The number of argument required is not known yet.
7891 Just accept it for now. */
7893 else
7894 {
7896 tree argparm;
7898 /* Strip alias templates that are equivalent to another
7899 template. */
7905 args))
7906 {
7909 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7910 TEMPLATE_DECL. */
7912 {
7917 }
7918 }
7919 else
7920 {
7922 {
7929 }
7932 }
7934 // Check that the constraints are compatible before allowing the
7935 // substitution.
7938 {
7940 {
7946 }
7948 }
7949 }
7950 }
7951 else
7953 /* We only form one instance of each template specialization.
7954 Therefore, if we use a non-canonical variant (i.e., a
7955 typedef), any future messages referring to the type will use
7956 the typedef, which is confusing if those future uses do not
7957 themselves also use the typedef. */
7960 }
7961 else
7962 {
7966 {
7970 }
7971 else
7979 /* We used to call digest_init here. However, digest_init
7980 will report errors, which we don't want when complain
7981 is zero. More importantly, digest_init will try too
7982 hard to convert things: for example, `0' should not be
7983 converted to pointer type at this point according to
7984 the standard. Accepting this is not merely an
7985 extension, since deciding whether or not these
7986 conversions can occur is part of determining which
7987 function template to call, or whether a given explicit
7988 argument specification is valid. */
7990 else
7991 {
7994 }
8004 {
8005 /* Reject template arguments that are references to built-in
8006 functions with no library fallbacks. */
8015 }
8018 {
8019 /* Strip typedefs from the SCOPE_REF. */
8022 complain);
8025 }
8026 }
8029 }
8031 /* Coerces the remaining template arguments in INNER_ARGS (from
8032 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8033 Returns the coerced argument pack. PARM_IDX is the position of this
8034 parameter in the template parameter list. ARGS is the original
8035 template argument list. */
8036 static tree
8039 tree args,
8040 tree inner_args,
8042 tree new_args,
8044 tree in_decl,
8045 tsubst_flags_t complain)
8046 {
8049 tree packed_args;
8050 tree argument_pack;
8057 {
8058 /* When the template parameter is a non-type template parameter pack
8059 or template template parameter pack whose type or template
8060 parameters use parameter packs, we know exactly how many arguments
8061 we are looking for. Build a vector of the instantiated decls for
8062 these template parameters in PACKED_PARMS. */
8063 /* We can't use make_pack_expansion here because it would interpret a
8064 _DECL as a use rather than a declaration. */
8078 /* If we're doing a partial instantiation of a member template,
8079 verify that all of the types used for the non-type
8080 template parameter pack are, in fact, valid for non-type
8081 template parameters. */
8084 {
8087 {
8091 }
8092 /* We don't know how many args we have yet, just
8093 use the unconverted ones for now. */
8095 }
8098 }
8099 /* Check if we have a placeholder pack, which indicates we're
8100 in the context of a introduction list. In that case we want
8101 to match this pack to the single placeholder. */
8105 {
8108 }
8109 else
8112 /* Convert the remaining arguments, which will be a part of the
8113 parameter pack "parm". */
8116 {
8122 {
8123 /* Once we've packed as many args as we have types, stop. */
8127 /* We don't know how many args we have yet, just
8128 use the unconverted ones for now. */
8130 else
8132 }
8135 {
8138 }
8139 else
8142 in_decl);
8146 }
8150 {
8155 }
8160 else
8161 {
8164 }
8171 }
8173 /* Returns the number of pack expansions in the template argument vector
8174 ARGS. */
8176 static int
8178 {
8183 {
8187 }
8189 }
8191 /* Convert all template arguments to their appropriate types, and
8192 return a vector containing the innermost resulting template
8193 arguments. If any error occurs, return error_mark_node. Error and
8194 warning messages are issued under control of COMPLAIN.
8196 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8197 for arguments not specified in ARGS. Otherwise, if
8198 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8199 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8200 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8201 ARGS. */
8203 static tree
8205 tree args,
8206 tree in_decl,
8207 tsubst_flags_t complain,
8210 {
8212 tree orig_inner_args;
8213 tree inner_args;
8214 tree new_args;
8215 tree new_inner_args;
8219 /* When used as a boolean value, indicates whether this is a
8220 variadic template parameter list. Since it's an int, we can also
8221 subtract it from nparms to get the number of non-variadic
8222 parameters. */
8227 /* Likewise for parameters with default arguments. */
8235 /* Determine if there are any parameter packs or default arguments. */
8237 {
8245 }
8248 /* If there are no parameters that follow a parameter pack, we need to
8249 expand any argument packs so that we can deduce a parameter pack from
8250 some non-packed args followed by an argument pack, as in variadic85.C.
8251 If there are such parameters, we need to leave argument packs intact
8252 so the arguments are assigned properly. This can happen when dealing
8253 with a nested class inside a partial specialization of a class
8254 template, as in variadic92.C, or when deducing a template parameter pack
8255 from a sub-declarator, as in variadic114.C. */
8259 /* Count any pack expansion args. */
8265 && require_all_args
8266 && !variadic_args_p
8267 && (!use_default_args
8270 {
8272 {
8274 {
8278 }
8279 else
8286 }
8289 }
8290 /* We can't pass a pack expansion to a non-pack parameter of an alias
8291 template (DR 1430). */
8295 && variadic_args_p
8297 {
8299 {
8301 {
8307 {
8310 "pack expansion argument for non-pack parameter "
8312 else
8314 "pack expansion argument for non-pack parameter "
8318 }
8319 }
8321 found:;
8322 }
8324 }
8326 /* We need to evaluate the template arguments, even though this
8327 template-id may be nested within a "sizeof". */
8336 {
8337 tree arg;
8338 tree parm;
8340 /* Get the Ith template parameter. */
8344 {
8347 }
8349 /* Calculate the next argument. */
8352 else
8357 {
8358 /* Some arguments will be placed in the
8359 template parameter pack PARM. */
8366 {
8367 /* We don't know how many args we have yet, just use the
8368 unconverted (and still packed) ones for now. */
8372 }
8376 /* Store this argument. */
8378 {
8379 lost++;
8380 /* We are done with all of the arguments. */
8382 }
8383 else
8384 {
8387 }
8390 }
8392 {
8394 {
8395 /* "If every valid specialization of a variadic template
8396 requires an empty template parameter pack, the template is
8397 ill-formed, no diagnostic required." So check that the
8398 pattern works with this parameter. */
8403 in_decl);
8405 {
8410 }
8412 /* Recover from missing typename. */
8416 /* We don't know how many args we have yet, just
8417 use the unconverted ones for now. */
8421 }
8422 }
8424 {
8425 /* There must be a default arg in this case. */
8428 /* The position of the first default template argument,
8429 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8430 Record that. */
8434 }
8435 else
8439 {
8442 }
8444 /* This only occurs if there was an error in the template
8445 parameter list itself (which we would already have
8446 reported) that we are trying to recover from, e.g., a class
8447 template with a parameter list such as
8448 template<typename..., typename>. */
8450 else
8456 lost++;
8458 }
8463 {
8465 {
8470 }
8472 }
8482 }
8484 /* Convert all template arguments to their appropriate types, and
8485 return a vector containing the innermost resulting template
8486 arguments. If any error occurs, return error_mark_node. Error and
8487 warning messages are not issued.
8489 Note that no function argument deduction is performed, and default
8490 arguments are used to fill in unspecified arguments. */
8491 tree
8493 {
8495 }
8497 /* Convert all template arguments to their appropriate type, and
8498 instantiate default arguments as needed. This returns a vector
8499 containing the innermost resulting template arguments, or
8500 error_mark_node if unsuccessful. */
8501 tree
8503 tsubst_flags_t complain)
8504 {
8506 }
8508 /* Like coerce_template_parms. If PARMS represents all template
8509 parameters levels, this function returns a vector of vectors
8510 representing all the resulting argument levels. Note that in this
8511 case, only the innermost arguments are coerced because the
8512 outermost ones are supposed to have been coerced already.
8514 Otherwise, if PARMS represents only (the innermost) vector of
8515 parameters, this function returns a vector containing just the
8516 innermost resulting arguments. */
8518 static tree
8520 tree args,
8521 tree in_decl,
8522 tsubst_flags_t complain,
8525 {
8528 tree coerced_args;
8531 {
8533 tree level;
8539 {
8540 tree l;
8544 require_all_args,
8545 use_default_args);
8546 else
8553 }
8554 }
8555 else
8558 require_all_args,
8559 use_default_args);
8561 }
8563 /* Returns 1 if template args OT and NT are equivalent. */
8565 int
8567 {
8576 /* For member templates */
8585 {
8602 }
8606 {
8609 /* Don't treat an alias template specialization with dependent
8610 arguments as equivalent to its underlying type when used as a
8611 template argument; we need them to be distinct so that we
8612 substitute into the specialization arguments at instantiation
8613 time. And aliases can't be equivalent without being ==, so
8614 we don't need to look any deeper.
8616 During partial ordering, however, we need to treat them normally so
8617 that we can order uses of the same alias with different
8618 cv-qualification (79960). */
8622 else
8624 }
8627 else
8628 {
8629 /* Try to treat a template non-type argument that has been converted
8630 to the parameter type as equivalent to one that hasn't yet. */
8643 }
8644 }
8646 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8647 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8648 NEWARG_PTR with the offending arguments if they are non-NULL. */
8650 int
8654 {
8667 {
8672 {
8678 }
8679 }
8681 }
8685 {
8687 }
8689 static void
8691 {
8701 /* We are called both from instantiate_decl, where we've already had a
8702 tinst_level pushed, and instantiate_template, where we haven't.
8703 Compensate. */
8714 else
8723 }
8726 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8727 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8728 documentation for TEMPLATE_ID_EXPR. */
8730 tree
8732 {
8733 tree type;
8741 {
8744 }
8747 {
8749 unknown_type_node,
8751 arglist);
8753 }
8760 }
8762 /* Within the scope of a template class S<T>, the name S gets bound
8763 (in build_self_reference) to a TYPE_DECL for the class, not a
8764 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8765 or one of its enclosing classes, and that type is a template,
8766 return the associated TEMPLATE_DECL. Otherwise, the original
8767 DECL is returned.
8769 Also handle the case when DECL is a TREE_LIST of ambiguous
8770 injected-class-names from different bases. */
8772 tree
8774 {
8778 /* DR 176: A lookup that finds an injected-class-name (10.2
8779 [class.member.lookup]) can result in an ambiguity in certain cases
8780 (for example, if it is found in more than one base class). If all of
8781 the injected-class-names that are found refer to specializations of
8782 the same class template, and if the name is followed by a
8783 template-argument-list, the reference refers to the class template
8784 itself and not a specialization thereof, and is not ambiguous. */
8786 {
8789 {
8795 }
8798 else
8800 }
8806 }
8808 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8809 parameters, find the desired type.
8811 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8813 IN_DECL, if non-NULL, is the template declaration we are trying to
8814 instantiate.
8816 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8817 the class we are looking up.
8819 Issue error and warning messages under control of COMPLAIN.
8821 If the template class is really a local class in a template
8822 function, then the FUNCTION_CONTEXT is the function in which it is
8823 being instantiated.
8825 ??? Note that this function is currently called *twice* for each
8826 template-id: the first time from the parser, while creating the
8827 incomplete type (finish_template_type), and the second type during the
8828 real instantiation (instantiate_template_class). This is surely something
8829 that we want to avoid. It also causes some problems with argument
8830 coercion (see convert_nontype_argument for more information on this). */
8832 static tree
8835 {
8837 tree t;
8840 spec_entry elt;
8841 hashval_t hash;
8844 {
8848 else
8849 {
8856 }
8859 }
8861 {
8864 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8865 an implicit typename for the second A. Deal with it. */
8870 {
8873 }
8874 }
8877 {
8880 }
8882 {
8886 }
8888 {
8891 }
8893 /* Issue an error message if we didn't find a template. */
8895 {
8899 }
8902 /* Make sure it's a user visible template, if it was named by
8903 the user. */
8906 {
8908 {
8912 }
8914 }
8918 /* An alias that just changes the name of a template is equivalent to the
8919 other template, so if any of the arguments are pack expansions, strip
8920 the alias to avoid problems with a pack expansion passed to a non-pack
8921 alias template parameter (DR 1430). */
8926 {
8927 tree parm;
8936 }
8937 else
8938 {
8940 tree gen_tmpl;
8941 tree type_decl;
8949 /* An error occurred while building the template TEMPL, and a
8950 diagnostic has most certainly been emitted for that
8951 already. Let's propagate that error. */
8960 {
8961 /* We've been given an incomplete set of template arguments.
8962 For example, given:
8964 template <class T> struct S1 {
8965 template <class U> struct S2 {};
8966 template <class U> struct S2<U*> {};
8967 };
8969 we will be called with an ARGLIST of `U*', but the
8970 TEMPLATE will be `template <class T> template
8971 <class U> struct S1<T>::S2'. We must fill in the missing
8972 arguments. */
8976 }
8978 /* Now we should have enough arguments. */
8981 /* From here on, we're only interested in the most general
8982 template. */
8984 /* Calculate the BOUND_ARGS. These will be the args that are
8985 actually tsubst'd into the definition to create the
8986 instantiation. */
8988 complain,
8993 /* We were unable to bind the arguments. */
8996 /* In the scope of a template class, explicit references to the
8997 template class refer to the type of the template, not any
8998 instantiation of it. For example, in:
9000 template <class T> class C { void f(C<T>); }
9002 the `C<T>' is just the same as `C'. Outside of the
9003 class, however, such a reference is an instantiation. */
9007 {
9012 }
9014 /* If we already have this specialization, return it. */
9024 /* If the the template's constraints are not satisfied,
9025 then we cannot form a valid type.
9027 Note that the check is deferred until after the hash
9028 lookup. This prevents redundant checks on previously
9029 instantiated specializations. */
9031 {
9033 {
9036 }
9038 }
9042 /* If the deduced arguments are invalid, then the binding
9043 failed. */
9047 complain))
9054 {
9059 }
9069 /* Create the type. */
9071 {
9072 /* The user referred to a specialization of an alias
9073 template represented by GEN_TMPL.
9075 [temp.alias]/2 says:
9077 When a template-id refers to the specialization of an
9078 alias template, it is equivalent to the associated
9079 type obtained by substitution of its
9080 template-arguments for the template-parameters in the
9081 type-id of the alias template. */
9084 /* Note that the call above (by indirectly calling
9085 register_specialization in tsubst_decl) registers the
9086 TYPE_DECL representing the specialization of the alias
9087 template. So next time someone substitutes ARGLIST for
9088 the template parms into the alias template (GEN_TMPL),
9089 she'll get that TYPE_DECL back. */
9093 }
9095 {
9097 {
9108 }
9109 else
9110 {
9111 /* We don't want to call start_enum for this type, since
9112 the values for the enumeration constants may involve
9113 template parameters. And, no one should be interested
9114 in the enumeration constants for such a type. */
9117 }
9121 }
9123 {
9124 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9125 instantiated here. */
9133 /* A local class. Make sure the decl gets registered properly. */
9138 /* This instantiation is another name for the primary
9139 template type. Set the TYPE_CANONICAL field
9140 appropriately. */
9143 /* Some of the template arguments require structural
9144 equality testing, so this template class requires
9145 structural equality testing. */
9147 }
9148 else
9151 /* If we called start_enum or pushtag above, this information
9152 will already be set up. */
9154 {
9161 }
9162 else
9166 {
9172 {
9175 }
9176 }
9180 {
9184 {
9185 tree attributes
9193 }
9194 }
9196 /* Let's consider the explicit specialization of a member
9197 of a class template specialization that is implicitly instantiated,
9198 e.g.:
9199 template<class T>
9200 struct S
9201 {
9202 template<class U> struct M {}; //#0
9203 };
9205 template<>
9206 template<>
9207 struct S<int>::M<char> //#1
9208 {
9209 int i;
9210 };
9211 [temp.expl.spec]/4 says this is valid.
9213 In this case, when we write:
9214 S<int>::M<char> m;
9216 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9217 the one of #0.
9219 When we encounter #1, we want to store the partial instantiation
9220 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9222 For all cases other than this "explicit specialization of member of a
9223 class template", we just want to store the most general template into
9224 the CLASSTYPE_TI_TEMPLATE of M.
9226 This case of "explicit specialization of member of a class template"
9227 only happens when:
9228 1/ the enclosing class is an instantiation of, and therefore not
9229 the same as, the context of the most general template, and
9230 2/ we aren't looking at the partial instantiation itself, i.e.
9231 the innermost arguments are not the same as the innermost parms of
9232 the most general template.
9234 So it's only when 1/ and 2/ happens that we want to use the partial
9235 instantiation of the member template in lieu of its most general
9236 template. */
9240 /* the enclosing class must be an instantiation... */
9243 {
9247 tree partial_inst_args =
9254 use_partial_inst_tmpl =
9255 /*...and we must not be looking at the partial instantiation
9256 itself. */
9258 partial_inst_args);
9259 }
9262 /* This case is easy; there are no member templates involved. */
9264 else
9265 {
9266 /* This is a full instantiation of a member template. Find
9267 the partial instantiation of which this is an instance. */
9269 /* Temporarily reduce by one the number of levels in the ARGLIST
9270 so as to avoid comparing the last set of arguments. */
9274 /* FOUND is either a proper class type, or an alias
9275 template specialization. In the later case, it's a
9276 TYPE_DECL, resulting from the substituting of arguments
9277 for parameters in the TYPE_DECL of the alias template
9278 done earlier. So be careful while getting the template
9279 of FOUND. */
9281 ? found
9285 }
9287 // Build template info for the new specialization.
9296 /* Note this use of the partial instantiation so we can check it
9297 later in maybe_process_partial_specialization. */
9304 /* Now that the type has been registered on the instantiations
9305 list, we set up the enumerators. Because the enumeration
9306 constants may involve the enumeration type itself, we make
9307 sure to register the type first, and then create the
9308 constants. That way, doing tsubst_expr for the enumeration
9309 constants won't result in recursive calls here; we'll find
9310 the instantiation and exit above. */
9314 /* If the type makes use of template parameters, the
9315 code that generates debugging information will crash. */
9318 /* Possibly limit visibility based on template args. */
9325 }
9326 }
9328 /* Wrapper for lookup_template_class_1. */
9330 tree
9333 {
9334 tree ret;
9340 }
9342 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9344 tree
9346 {
9347 /* The type of the expression is NULL_TREE since the template-id could refer
9348 to an explicit or partial specialization. */
9351 /* Except that concepts are always bool. */
9354 }
9356 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9358 tree
9360 {
9364 /* We never want to return a VAR_DECL for a variable concept, since they
9365 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9380 {
9382 {
9385 }
9387 }
9389 /* If a template-id refers to a specialization of a variable
9390 concept, then the expression is true if and only if the
9391 concept's constraints are satisfied by the given template
9392 arguments.
9394 NOTE: This is an extension of Concepts Lite TS that
9395 allows constraints to be used in expressions. */
9397 {
9400 }
9403 }
9405 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9406 TARGS template args, and instantiate it if it's not dependent. */
9408 tree
9410 tsubst_flags_t complain)
9411 {
9414 {
9417 }
9420 }
9422 \f
9423 struct pair_fn_data
9424 {
9425 tree_fn_t fn;
9426 tree_fn_t any_fn;
9428 /* True when we should also visit template parameters that occur in
9429 non-deduced contexts. */
9432 };
9434 /* Called from for_each_template_parm via walk_tree. */
9436 static tree
9438 {
9445 #define WALK_SUBTREE(NODE) \
9446 do \
9447 { \
9448 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9449 pfd->include_nondeduced_p, \
9450 pfd->any_fn); \
9451 if (result) goto out; \
9452 } \
9453 while (0)
9463 {
9467 /* Fall through. */
9473 else
9483 /* Since we're not going to walk subtrees, we have to do this
9484 explicitly here. */
9486 /* Fall through. */
9489 /* Check the return type. */
9492 /* Check the parameter types. Since default arguments are not
9493 instantiated until they are needed, the TYPE_ARG_TYPES may
9494 contain expressions that involve template parameters. But,
9495 no-one should be looking at them yet. And, once they're
9496 instantiated, they don't contain template parameters, so
9497 there's no point in looking at them then, either. */
9498 {
9499 tree parm;
9504 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9505 want walk_tree walking into them itself. */
9507 }
9510 {
9514 }
9531 /* Fall through. */
9543 /* Record template parameters such as `T' inside `TT<T>'. */
9545 /* Fall through. */
9557 /* A template template parameter is encountered. */
9561 /* Already substituted template template parameter */
9566 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9567 partial instantiation. */
9579 /* If there's no type, then this thing must be some expression
9580 involving template parameters. */
9602 }
9604 #undef WALK_SUBTREE
9606 /* We didn't find any template parameters we liked. */
9607 out:
9609 }
9611 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9612 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9613 call FN with the parameter and the DATA.
9614 If FN returns nonzero, the iteration is terminated, and
9615 for_each_template_parm returns 1. Otherwise, the iteration
9616 continues. If FN never returns a nonzero value, the value
9617 returned by for_each_template_parm is 0. If FN is NULL, it is
9618 considered to be the function which always returns 1.
9620 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9621 parameters that occur in non-deduced contexts. When false, only
9622 visits those template parameters that can be deduced. */
9624 static tree
9628 tree_fn_t any_fn)
9629 {
9631 tree result;
9633 /* Set up. */
9639 /* Walk the tree. (Conceptually, we would like to walk without
9640 duplicates, but for_each_template_parm_r recursively calls
9641 for_each_template_parm, so we would need to reorganize a fair
9642 bit to use walk_tree_without_duplicates, so we keep our own
9643 visited list.) */
9646 else
9649 for_each_template_parm_r,
9653 /* Clean up. */
9655 {
9658 }
9661 }
9663 /* Returns true if T depends on any template parameter. */
9665 int
9667 {
9697 else
9698 {
9701 }
9706 }
9708 /* Returns true iff current_function_decl is an incompletely instantiated
9709 template. Useful instead of processing_template_decl because the latter
9710 is set to 0 during instantiate_non_dependent_expr. */
9712 bool
9714 {
9723 }
9725 /* Returns true if T depends on any template parameter with level LEVEL. */
9727 bool
9729 {
9732 }
9734 /* Returns true if the signature of DECL depends on any template parameter from
9735 its enclosing class. */
9737 bool
9739 {
9749 template_parm_outer_level,
9759 }
9761 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9762 ill-formed translation unit, i.e. a variable or function that isn't
9763 usable in a constant expression. */
9767 {
9772 }
9774 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9775 neglectable and instantiated from within an erroneous instantiation. */
9777 static bool
9779 {
9790 }
9798 /* We're starting to instantiate D; record the template instantiation context
9799 for diagnostics and to restore it later. */
9801 bool
9803 {
9805 }
9807 /* We're starting to instantiate D; record the template instantiation context
9808 at LOC for diagnostics and to restore it later. */
9810 bool
9812 {
9816 {
9817 /* Tell error.c not to try to instantiate any templates. */
9820 "template instantiation depth exceeds maximum of %d"
9822 max_tinst_depth);
9824 }
9826 /* If the current instantiation caused problems, don't let it instantiate
9827 anything else. Do allow deduction substitution and decls usable in
9828 constant expressions. */
9832 /* When not -quiet, dump template instantiations other than functions, since
9833 announce_function will take care of those. */
9852 }
9854 /* We're done instantiating this template; return to the instantiation
9855 context. */
9857 void
9859 {
9860 /* Restore the filename and line number stashed away when we started
9861 this instantiation. */
9865 }
9867 /* We're instantiating a deferred template; restore the template
9868 instantiation context in which the instantiation was requested, which
9869 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9871 static tree
9873 {
9885 }
9887 /* Returns the TINST_LEVEL which gives the original instantiation
9888 context. */
9892 {
9898 }
9900 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9901 vector of template arguments, as for tsubst.
9903 Returns an appropriate tsubst'd friend declaration. */
9905 static tree
9907 {
9908 tree new_friend;
9913 /* This was a friend declared with an explicit template
9914 argument list, e.g.:
9916 friend void f<>(T);
9918 to indicate that f was a template instantiation, not a new
9919 function declaration. Now, we have to figure out what
9920 instantiation of what template. */
9921 {
9923 tree new_args;
9924 tree tmpl;
9927 /* Friend functions are looked up in the containing namespace scope.
9928 We must enter that scope, to avoid finding member functions of the
9929 current class with same name. */
9944 tsk_none);
9946 }
9950 /* The NEW_FRIEND will look like an instantiation, to the
9951 compiler, but is not an instantiation from the point of view of
9952 the language. For example, we might have had:
9954 template <class T> struct S {
9955 template <class U> friend void f(T, U);
9956 };
9958 Then, in S<int>, template <class U> void f(int, U) is not an
9959 instantiation of anything. */
9965 {
9969 }
9971 /* The mangled name for the NEW_FRIEND is incorrect. The function
9972 is not a template instantiation and should not be mangled like
9973 one. Therefore, we forget the mangling here; we'll recompute it
9974 later if we need it. */
9976 {
9979 }
9982 {
9983 tree old_decl;
9984 tree new_friend_template_info;
9985 tree new_friend_result_template_info;
9986 tree ns;
9989 /* We must save some information from NEW_FRIEND before calling
9990 duplicate decls since that function will free NEW_FRIEND if
9991 possible. */
9993 new_friend_is_defn =
9998 {
9999 /* This declaration is a `primary' template. */
10002 new_friend_result_template_info
10004 }
10005 else
10008 /* Inside pushdecl_namespace_level, we will push into the
10009 current namespace. However, the friend function should go
10010 into the namespace of the template. */
10020 {
10021 /* This new friend declaration matched an existing
10022 declaration. For example, given:
10024 template <class T> void f(T);
10025 template <class U> class C {
10026 template <class T> friend void f(T) {}
10027 };
10029 the friend declaration actually provides the definition
10030 of `f', once C has been instantiated for some type. So,
10031 old_decl will be the out-of-class template declaration,
10032 while new_friend is the in-class definition.
10034 But, if `f' was called before this point, the
10035 instantiation of `f' will have DECL_TI_ARGS corresponding
10036 to `T' but not to `U', references to which might appear
10037 in the definition of `f'. Previously, the most general
10038 template for an instantiation of `f' was the out-of-class
10039 version; now it is the in-class version. Therefore, we
10040 run through all specialization of `f', adding to their
10041 DECL_TI_ARGS appropriately. In particular, they need a
10042 new set of outer arguments, corresponding to the
10043 arguments for this class instantiation.
10045 The same situation can arise with something like this:
10047 friend void f(int);
10048 template <class T> class C {
10049 friend void f(T) {}
10050 };
10052 when `C<int>' is instantiated. Now, `f(int)' is defined
10053 in the class. */
10056 /* On the other hand, if the in-class declaration does
10057 *not* provide a definition, then we don't want to alter
10058 existing definitions. We can just leave everything
10059 alone. */
10060 ;
10061 else
10062 {
10066 /* Overwrite whatever template info was there before, if
10067 any, with the new template information pertaining to
10068 the declaration. */
10072 {
10073 /* We should have called reregister_specialization in
10074 duplicate_decls. */
10079 /* Instantiate it if the global has already been used. */
10083 }
10084 else
10085 {
10086 tree t;
10088 /* Indicate that the old function template is a partial
10089 instantiation. */
10097 /* Reassign any specializations already in the hash table
10098 to the new more general template, and add the
10099 additional template args. */
10103 {
10105 spec_entry elt;
10117 register_specialization
10120 }
10122 }
10123 }
10125 /* The information from NEW_FRIEND has been merged into OLD_DECL
10126 by duplicate_decls. */
10128 }
10129 }
10130 else
10131 {
10135 /* In the code
10136 template <class T> class C {
10137 template <class U> friend void C1<U>::f (); // case 1
10138 friend void C2<T>::f (); // case 2
10139 };
10140 we only need to make sure CONTEXT is a complete type for
10141 case 2. To distinguish between the two cases, we note that
10142 CONTEXT of case 1 remains dependent type after tsubst while
10143 this isn't true for case 2. */
10153 {
10155 /* do_friend adds the TEMPLATE_DECL for any member friend
10156 template even if it isn't a member template, i.e.
10157 template <class T> friend A<T>::f();
10158 Look through it in that case. */
10162 /* Check to see that the declaration is really present, and,
10163 possibly obtain an improved declaration. */
10168 }
10169 }
10172 }
10174 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10175 template arguments, as for tsubst.
10177 Returns an appropriate tsubst'd friend type or error_mark_node on
10178 failure. */
10180 static tree
10182 {
10183 tree tmpl;
10186 {
10189 }
10194 else
10202 {
10203 /* The friend template has already been declared. Just
10204 check to see that the declarations match, and install any new
10205 default parameters. We must tsubst the default parameters,
10206 of course. We only need the innermost template parameters
10207 because that is all that redeclare_class_template will look
10208 at. */
10211 {
10219 }
10220 }
10221 else
10222 {
10223 /* The friend template has not already been declared. In this
10224 case, the instantiation of the template class will cause the
10225 injection of this template into the namespace scope. */
10229 {
10230 /* The new TMPL is not an instantiation of anything, so we
10231 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10232 for the new type because that is supposed to be the
10233 corresponding template decl, i.e., TMPL. */
10240 /* It is hidden. */
10245 /* Inject this template into the enclosing namspace scope. */
10247 }
10248 }
10252 else
10256 }
10258 /* Returns zero if TYPE cannot be completed later due to circularity.
10259 Otherwise returns one. */
10261 static int
10263 {
10273 else
10275 }
10280 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10281 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10283 static tree
10286 {
10295 {
10302 clauses
10306 else
10308 }
10309 /* If the first attribute argument is an identifier, don't
10310 pass it through tsubst. Attributes like mode, format,
10311 cleanup and several target specific attributes expect it
10312 unmodified. */
10314 {
10315 tree chain
10320 }
10322 {
10323 /* An attribute pack expansion. */
10332 {
10336 }
10338 }
10339 else
10346 }
10348 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10349 unchanged or a new TREE_LIST chain. */
10351 static tree
10354 {
10359 {
10363 }
10367 {
10370 {
10373 {
10379 }
10380 }
10382 }
10385 }
10387 /* Apply any attributes which had to be deferred until instantiation
10388 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10389 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10391 static void
10394 {
10396 tree t;
10403 {
10407 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10408 to our attributes parameter. */
10410 }
10411 else
10412 {
10414 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10415 lookup_template_class_1, and should be preserved. */
10419 }
10423 {
10427 }
10431 {
10436 {
10439 {
10445 }
10446 else
10448 }
10451 }
10452 }
10454 /* Perform (or defer) access check for typedefs that were referenced
10455 from within the template TMPL code.
10456 This is a subroutine of instantiate_decl and instantiate_class_template.
10457 TMPL is the template to consider and TARGS is the list of arguments of
10458 that template. */
10460 static void
10462 {
10463 location_t saved_location;
10474 {
10486 /* Make access check error messages point to the location
10487 of the use of the typedef. */
10491 tf_warning_or_error);
10492 }
10494 }
10496 static tree
10498 {
10500 tree typedecl;
10501 tree pbinfo;
10502 tree base_list;
10504 tree fn_context;
10513 /* Figure out which template is being instantiated. */
10517 /* Mark the type as in the process of being defined. */
10520 /* Determine what specialization of the original template to
10521 instantiate. */
10526 {
10527 /* This TYPE is actually an instantiation of a partial
10528 specialization. We replace the innermost set of ARGS with
10529 the arguments appropriate for substitution. For example,
10530 given:
10532 template <class T> struct S {};
10533 template <class T> struct S<T*> {};
10535 and supposing that we are instantiating S<int*>, ARGS will
10536 presently be {int*} -- but we need {int}. */
10539 }
10540 else
10541 {
10544 }
10546 /* If the template we're instantiating is incomplete, then clearly
10547 there's nothing we can do. */
10549 {
10550 /* We can try again later. */
10553 }
10555 /* If we've recursively instantiated too many templates, stop. */
10559 /* We may be in the middle of deferred access check. Disable
10560 it now. */
10567 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10572 else
10573 {
10576 }
10577 /* Use #pragma pack from the template context. */
10583 /* Set the input location to the most specialized template definition.
10584 This is needed if tsubsting causes an error. */
10596 {
10599 /* Adjust visibility for template arguments. */
10601 }
10607 /* We should never instantiate a nested class before its enclosing
10608 class; we need to look up the nested class by name before we can
10609 instantiate it, and that lookup should instantiate the enclosing
10610 class. */
10616 {
10617 tree pbase_binfo;
10618 tree pushed_scope;
10621 /* We must enter the scope containing the type, as that is where
10622 the accessibility of types named in dependent bases are
10623 looked up from. */
10626 /* Substitute into each of the bases to determine the actual
10627 basetypes. */
10629 {
10630 tree base;
10636 {
10637 expanded_bases =
10644 }
10647 {
10649 /* Extract the already-expanded base class. */
10651 else
10652 /* Substitute to figure out the base class. */
10654 NULL_TREE);
10662 }
10663 }
10665 /* The list is now in reverse order; correct that. */
10670 }
10671 /* Now call xref_basetypes to set up all the base-class
10672 information. */
10680 /* Now that our base classes are set up, enter the scope of the
10681 class, so that name lookups into base classes, etc. will work
10682 correctly. This is precisely analogous to what we do in
10683 begin_class_definition when defining an ordinary non-template
10684 class, except we also need to push the enclosing classes. */
10687 /* Now members are processed in the order of declaration. */
10690 {
10694 {
10696 {
10698 /* A closure type for a lambda in an NSDMI or default argument.
10699 Ignore it; it will be regenerated when needed. */
10702 /* Build new CLASSTYPE_NESTED_UTDS. */
10704 tree newtag;
10710 /* If the member is a class template, then -- even after
10711 substitution -- there may be dependent types in the
10712 template argument list for the class. We increment
10713 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10714 that function will assume that no types are dependent
10715 when outside of a template. */
10725 {
10729 /* Unfortunately, lookup_template_class sets
10730 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10731 instantiation (i.e., for the type of a member
10732 template class nested within a template class.)
10733 This behavior is required for
10734 maybe_process_partial_specialization to work
10735 correctly, but is not accurate in this case;
10736 the TAG is not an instantiation of anything.
10737 (The corresponding TEMPLATE_DECL is an
10738 instantiation, but the TYPE is not.) */
10741 /* Now, we call pushtag to put this NEWTAG into the scope of
10742 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10743 pushtag calling push_template_decl. We don't have to do
10744 this for enums because it will already have been done in
10745 tsubst_enum. */
10749 }
10750 }
10752 {
10753 tree r;
10762 /* Instantiate members marked with attribute used. */
10768 }
10771 /* A closure type for a lambda in an NSDMI or default argument.
10773 else
10774 {
10775 /* Build new TYPE_FIELDS. */
10777 {
10778 tree condition;
10781 condition =
10791 }
10793 {
10794 tree r;
10798 /* The file and line for this declaration, to
10799 assist in error message reporting. Since we
10800 called push_tinst_level above, we don't need to
10801 restore these. */
10811 {
10812 /* A capture pack became multiple fields. */
10815 }
10818 {
10822 {
10823 /* In [temp.inst]:
10825 [t]he initialization (and any associated
10826 side-effects) of a static data member does
10827 not occur unless the static data member is
10828 itself used in a way that requires the
10829 definition of the static data member to
10830 exist.
10832 Therefore, we do not substitute into the
10833 initialized for the static data member here. */
10834 finish_static_data_member_decl
10840 /* Instantiate members marked with attribute used. */
10843 }
10845 {
10846 /* Determine whether R has a valid type and can be
10847 completed later. If R is invalid, then its type
10848 is replaced by error_mark_node. */
10854 {
10855 /* If R's type couldn't be completed and
10856 it isn't a flexible array member (whose
10857 type is incomplete by definition) give
10858 an error. */
10861 }
10862 }
10864 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10865 such a thing will already have been added to the field
10866 list by tsubst_enum in finish_member_declaration in the
10867 CLASSTYPE_NESTED_UTDS case above. */
10871 {
10874 }
10875 }
10876 }
10877 }
10878 }
10879 else
10880 {
10883 {
10884 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10890 {
10891 /* template <class T> friend class C; */
10894 }
10896 {
10897 /* template <class T> friend class C::D; */
10903 }
10906 {
10907 /* This could be either
10909 friend class T::C;
10911 when dependent_type_p is false or
10913 template <class U> friend class T::C;
10915 otherwise. */
10916 /* Bump processing_template_decl in case this is something like
10917 template <class T> friend struct A<T>::B. */
10924 }
10928 {
10929 /* friend class C;
10931 where C hasn't been declared yet. Let's lookup name
10932 from namespace scope directly, bypassing any name that
10933 come from dependent base class. */
10936 /* The call to xref_tag_from_type does injection for friend
10937 classes. */
10939 friend_type =
10943 }
10945 /* friend class C<T>; */
10948 /* Otherwise it's
10950 friend class C;
10952 where C is already declared or
10954 friend class C<int>;
10956 We don't have to do anything in these cases. */
10959 /* Trick make_friend_class into realizing that the friend
10960 we're adding is a template, not an ordinary class. It's
10961 important that we use make_friend_class since it will
10962 perform some error-checking and output cross-reference
10963 information. */
10971 }
10972 else
10973 {
10974 /* Build new DECL_FRIENDLIST. */
10975 tree r;
10977 /* The file and line for this declaration, to
10978 assist in error message reporting. Since we
10979 called push_tinst_level above, we don't need to
10980 restore these. */
10984 {
10987 }
10992 {
10995 }
10996 }
10997 }
10998 }
11001 {
11002 /* Restore these before substituting into the lambda capture
11003 initializers. */
11006 }
11008 /* Set the file and line number information to whatever is given for
11009 the class itself. This puts error messages involving generated
11010 implicit functions at a predictable point, and the same point
11011 that would be used for non-template classes. */
11018 /* We don't instantiate default arguments for member functions. 14.7.1:
11020 The implicit instantiation of a class template specialization causes
11021 the implicit instantiation of the declarations, but not of the
11022 definitions or default arguments, of the class member functions,
11023 member classes, static data members and member templates.... */
11025 /* Some typedefs referenced from within the template code need to be access
11026 checked at template instantiation time, i.e now. These types were
11027 added to the template at parsing time. Let's get those and perform
11028 the access checks then. */
11038 /* The vtable for a template class can be emitted in any translation
11039 unit in which the class is instantiated. When there is no key
11040 method, however, finish_struct_1 will already have added TYPE to
11041 the keyed_classes. */
11046 }
11048 /* Wrapper for instantiate_class_template_1. */
11050 tree
11052 {
11053 tree ret;
11058 }
11060 static tree
11062 {
11063 tree r;
11069 else
11070 {
11077 }
11079 }
11081 /* Given a function parameter pack TMPL_PARM and some function parameters
11082 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11083 and set *SPEC_P to point at the next point in the list. */
11085 tree
11087 {
11088 /* Collect all of the extra "packed" parameters into an
11089 argument pack. */
11090 tree parmvec;
11100 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11104 {
11109 }
11111 /* Build the argument packs. */
11116 }
11118 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11119 NONTYPE_ARGUMENT_PACK. */
11121 static tree
11123 {
11125 }
11127 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11128 pack expansion with no extra args, 2 if it has extra args, or 0
11129 if it is not a pack expansion. */
11131 static int
11133 {
11139 /* A decl pack is itself an expansion. */
11146 }
11149 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11151 static tree
11153 {
11160 }
11162 /* This is a subroutine of tsubst_pack_expansion.
11164 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11165 mechanism to store the (non complete list of) arguments of the
11166 substitution and return a non substituted pack expansion, in order
11167 to wait for when we have enough arguments to really perform the
11168 substitution. */
11170 static bool
11174 {
11175 /* If one pack has an expansion and another pack has a normal
11176 argument or if one pack has an empty argument and an another
11177 one hasn't then tsubst_pack_expansion cannot perform the
11178 substitution and need to fall back on the
11179 PACK_EXPANSION_EXTRA mechanism. */
11187 {
11190 parm_pack;
11192 {
11197 /* We can't substitute a pack expansion with extra args into
11198 our pattern. */
11202 else
11204 }
11208 }
11210 }
11212 /* [temp.variadic]/6 says that:
11214 The instantiation of a pack expansion [...]
11215 produces a list E1,E2, ..., En, where N is the number of elements
11216 in the pack expansion parameters.
11218 This subroutine of tsubst_pack_expansion produces one of these Ei.
11220 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11221 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11222 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11223 INDEX is the index 'i' of the element Ei to produce. ARGS,
11224 COMPLAIN, and IN_DECL are the same parameters as for the
11225 tsubst_pack_expansion function.
11227 The function returns the resulting Ei upon successful completion,
11228 or error_mark_node.
11230 Note that this function possibly modifies the ARGS parameter, so
11231 it's the responsibility of the caller to restore it. */
11233 static tree
11235 tree parm_packs,
11237 tree args /* This parm gets
11239 tsubst_flags_t complain,
11240 tree in_decl)
11241 {
11242 tree t;
11245 /* For each parameter pack, change the substitution of the parameter
11246 pack to the ith argument in its argument pack, then expand the
11247 pattern. */
11249 {
11254 ith_elem_is_expansion |=
11257 /* Select the Ith argument from the pack. */
11261 {
11263 {
11268 }
11269 else
11271 }
11272 else
11273 {
11278 {
11280 /* Update the corresponding argument. */
11282 }
11283 else
11284 /* Re-use the ARGUMENT_PACK_SELECT. */
11286 }
11288 }
11290 /* Substitute into the PATTERN with the (possibly altered)
11291 arguments. */
11293 /* Expanding a fixed parameter pack from
11294 coerce_template_parameter_pack. */
11299 {
11302 else
11305 }
11309 else
11312 /* If the Ith argument pack element is a pack expansion, then
11313 the Ith element resulting from the substituting is going to
11314 be a pack expansion as well. */
11319 }
11321 /* When the unexpanded parameter pack in a fold expression expands to an empty
11322 sequence, the value of the expression is as follows; the program is
11323 ill-formed if the operator is not listed in this table.
11325 && true
11326 || false
11327 , void() */
11329 tree
11331 {
11335 {
11344 }
11350 }
11352 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11353 form an expression that combines the two terms using the
11354 operator of T. */
11356 static tree
11358 {
11362 // Handle compound assignment operators.
11367 {
11377 complain);
11378 }
11379 }
11381 /* Substitute ARGS into the pack of a fold expression T. */
11385 {
11387 }
11389 /* Substitute ARGS into the pack of a fold expression T. */
11393 {
11395 }
11397 /* Expand a PACK of arguments into a grouped as left fold.
11398 Given a pack containing elements A0, A1, ..., An and an
11399 operator @, this builds the expression:
11401 ((A0 @ A1) @ A2) ... @ An
11403 Note that PACK must not be empty.
11405 The operator is defined by the original fold expression T. */
11407 static tree
11409 {
11412 {
11415 }
11417 }
11419 /* Substitute into a unary left fold expression. */
11421 static tree
11423 tree in_decl)
11424 {
11429 {
11433 }
11436 else
11438 }
11440 /* Substitute into a binary left fold expression.
11442 Do ths by building a single (non-empty) vector of argumnts and
11443 building the expression from those elements. */
11445 static tree
11447 tree in_decl)
11448 {
11457 {
11462 }
11470 }
11472 /* Expand a PACK of arguments into a grouped as right fold.
11473 Given a pack containing elementns A0, A1, ..., and an
11474 operator @, this builds the expression:
11476 A0@ ... (An-2 @ (An-1 @ An))
11478 Note that PACK must not be empty.
11480 The operator is defined by the original fold expression T. */
11482 tree
11484 {
11485 // Build the expression.
11489 {
11492 }
11494 }
11496 /* Substitute into a unary right fold expression. */
11498 static tree
11500 tree in_decl)
11501 {
11506 {
11510 }
11513 else
11515 }
11517 /* Substitute into a binary right fold expression.
11519 Do ths by building a single (non-empty) vector of arguments and
11520 building the expression from those elements. */
11522 static tree
11524 tree in_decl)
11525 {
11534 {
11539 }
11548 }
11550 /* Walk through the pattern of a pack expansion, adding everything in
11551 local_specializations to a list. */
11553 struct el_data
11554 {
11555 tree extra;
11556 tsubst_flags_t complain;
11557 };
11558 static tree
11560 {
11565 {
11567 {
11568 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11571 {
11577 }
11579 {
11580 /* Handle lambda capture here, since we aren't doing any
11581 substitution now, and so tsubst_copy won't call
11582 process_outer_var_ref. */
11586 {
11592 {
11593 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11594 proxies. */
11596 {
11601 }
11603 }
11604 }
11605 }
11606 }
11610 }
11612 }
11613 static tree
11615 {
11619 }
11621 /* Substitute ARGS into T, which is an pack expansion
11622 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11623 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11624 (if only a partial substitution could be performed) or
11625 ERROR_MARK_NODE if there was an error. */
11626 tree
11628 tree in_decl)
11629 {
11630 tree pattern;
11635 tree result;
11643 /* Add in any args remembered from an earlier partial instantiation. */
11646 {
11648 {
11649 /* The partial instantiation involved local declarations collected in
11650 extract_local_specs; map from the general template to our local
11651 context. */
11657 /* else inst is already a full instantiation of the pack. */
11659 }
11662 }
11667 /* Determine the argument packs that will instantiate the parameter
11668 packs used in the expansion expression. While we're at it,
11669 compute the number of arguments to be expanded and make sure it
11670 is consistent. */
11673 {
11680 {
11685 else
11688 }
11690 {
11691 /* ??? Support use in other patterns. */
11695 }
11697 {
11698 /* We know we have correct local_specializations if this
11699 expansion is at function scope, or if we're dealing with a
11700 local parameter in a requires expression; for the latter,
11701 tsubst_requires_expr set it up appropriately. */
11704 else
11705 /* We can't rely on local_specializations for a parameter
11706 name used later in a function declaration (such as in a
11707 late-specified return type). Even if it exists, it might
11708 have the wrong value for a recursive call. */
11712 {
11713 /* This parameter pack was used in an unevaluated context. Just
11714 make a dummy decl, since it's only used for its type. */
11717 /* Partial instantiation of the parm_pack, we can't build
11718 up an argument pack yet. */
11720 else
11722 }
11724 /* This argument pack isn't fully instantiated yet. We set this
11725 flag rather than clear arg_pack because we do want to do the
11726 optimization below, and we don't want to substitute directly
11727 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
11728 where it isn't expected). */
11730 }
11732 {
11736 }
11737 else
11738 {
11744 }
11751 /* This can only happen if we forget to expand an argument
11752 pack somewhere else. Just return an error, silently. */
11753 {
11757 }
11760 {
11764 /* Don't bother trying to do a partial substitution with
11765 incomplete packs; we'll try again after deduction. */
11773 {
11778 pattern);
11779 else
11781 pattern);
11783 }
11785 /* Keep track of the parameter packs and their corresponding
11786 argument packs. */
11789 }
11790 else
11791 {
11792 /* We can't substitute for this parameter pack. We use a flag as
11793 well as the missing_level counter because function parameter
11794 packs don't have a level. */
11797 }
11798 }
11800 /* If the expansion is just T..., return the matching argument pack, unless
11801 we need to call convert_from_reference on all the elements. This is an
11802 important optimization; see c++/68422. */
11805 {
11808 /* If the argument pack is a single pack expansion, pull it out. */
11813 /* Types need no adjustment, nor does sizeof..., and if we still have
11814 some pack expansion args we won't do anything yet. */
11819 /* Also optimize expression pack expansions if we can tell that the
11820 elements won't have reference type. */
11826 /* Otherwise use the normal path so we get convert_from_reference. */
11827 }
11829 /* We cannot expand this expansion expression, because we don't have
11830 all of the argument packs we need. */
11832 {
11833 /* We got some full packs, but we can't substitute them in until we
11834 have values for all the packs. So remember these until then. */
11843 }
11845 {
11846 /* There were no real arguments, we're just replacing a parameter
11847 pack with another version of itself. Substitute into the
11848 pattern and return a PACK_EXPANSION_*. The caller will need to
11849 deal with that. */
11853 else
11857 }
11862 {
11863 /* We're in a late-specified return type, so create our own local
11864 specializations map; the current map is either NULL or (in the
11865 case of recursive unification) might have bindings that we don't
11866 want to use or alter. */
11869 }
11871 /* For each argument in each argument pack, substitute into the
11872 pattern. */
11876 {
11878 i,
11880 in_decl);
11883 {
11886 }
11887 }
11889 /* Update ARGS to restore the substitution from parameter packs to
11890 their argument packs. */
11892 {
11899 else
11900 {
11908 /* Update the corresponding argument. */
11912 else
11914 }
11915 }
11918 {
11921 }
11923 /* If the dependent pack arguments were such that we end up with only a
11924 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11930 }
11932 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11933 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11934 parameter packs; all parms generated from a function parameter pack will
11935 have the same DECL_PARM_INDEX. */
11937 tree
11939 {
11941 tree patparm;
11944 {
11950 }
11951 else
11952 {
11957 }
11960 }
11962 /* Make an argument pack out of the TREE_VEC VEC. */
11964 static tree
11966 {
11967 tree pack;
11971 else
11972 {
11975 }
11978 }
11980 /* Return an exact copy of template args T that can be modified
11981 independently. */
11983 static tree
11985 {
11993 {
11998 }
12004 }
12006 /* Substitute ARGS into the vector or list of template arguments T. */
12008 static tree
12010 {
12022 {
12024 tree new_arg;
12029 {
12030 /* Substitute into an expansion expression. */
12034 /* Add to the expanded length adjustment the number of
12035 expanded arguments. We subtract one from this
12036 measurement, because the argument pack expression
12037 itself is already counted as 1 in
12038 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12039 the argument pack is empty. */
12041 }
12043 {
12044 /* Substitute into each of the arguments. */
12053 else
12058 }
12059 else
12068 }
12073 /* Make space for the expanded arguments coming from template
12074 argument packs. */
12076 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12077 arguments for a member template.
12078 In that case each TREE_VEC in ORIG_T represents a level of template
12079 arguments, and ORIG_T won't carry any non defaulted argument count.
12080 It will rather be the nested TREE_VECs that will carry one.
12081 In other words, ORIG_T carries a non defaulted argument count only
12082 if it doesn't contain any nested TREE_VEC. */
12084 {
12088 }
12090 {
12094 {
12097 /* Now expand the template argument pack "in place". */
12100 }
12101 else
12102 {
12104 out++;
12105 }
12106 }
12109 }
12111 /* Substitute ARGS into one level PARMS of template parameters. */
12113 static tree
12115 {
12122 {
12130 }
12133 }
12135 /* Return the result of substituting ARGS into the template parameters
12136 given by PARMS. If there are m levels of ARGS and m + n levels of
12137 PARMS, then the result will contain n levels of PARMS. For
12138 example, if PARMS is `template <class T> template <class U>
12139 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12140 result will be `template <int*, double, class V>'. */
12142 static tree
12144 {
12148 /* When substituting into a template, we must set
12149 PROCESSING_TEMPLATE_DECL as the template parameters may be
12150 dependent if they are based on one-another, and the dependency
12151 predicates are short-circuit outside of templates. */
12158 {
12165 }
12170 }
12172 /* Return the result of substituting ARGS into one template parameter
12173 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12174 parameter and which TREE_PURPOSE is the default argument of the
12175 template parameter. */
12177 static tree
12179 {
12200 }
12202 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12203 type T. If T is not an aggregate or enumeration type, it is
12204 handled as if by tsubst. IN_DECL is as for tsubst. If
12205 ENTERING_SCOPE is nonzero, T is the context for a template which
12206 we are presently tsubst'ing. Return the substituted value. */
12208 static tree
12210 tree args,
12211 tsubst_flags_t complain,
12212 tree in_decl,
12214 {
12219 {
12224 /* Fall through. */
12228 {
12229 tree argvec;
12230 tree context;
12231 tree r;
12235 /* In "sizeof(X<I>)" we need to evaluate "I". */
12241 /* First, determine the context for the type we are looking
12242 up. */
12245 {
12248 /* If context is a nested class inside a class template,
12249 it may still need to be instantiated (c++/33959). */
12251 }
12253 /* Then, figure out what arguments are appropriate for the
12254 type we are trying to find. For example, given:
12256 template <class T> struct S;
12257 template <class T, class U> void f(T, U) { S<U> su; }
12259 and supposing that we are instantiating f<int, double>,
12260 then our ARGS will be {int, double}, but, when looking up
12261 S we only want {double}. */
12266 else
12267 {
12271 }
12277 }
12278 else
12279 /* This is not a template type, so there's nothing to do. */
12284 }
12285 }
12289 /* Substitute into the default argument ARG (a default argument for
12290 FN), which has the indicated TYPE. */
12292 tree
12294 tsubst_flags_t complain)
12295 {
12300 /* This can happen in invalid code. */
12315 /* This default argument came from a template. Instantiate the
12316 default argument here, not in tsubst. In the case of
12317 something like:
12319 template <class T>
12320 struct S {
12321 static T t();
12322 void f(T = t());
12323 };
12325 we must be careful to do name lookup in the scope of S<T>,
12326 rather than in the current class. */
12328 /* The "this" pointer is not valid in a default argument. */
12330 {
12335 }
12340 /* The default argument expression may cause implicitly defined
12341 member functions to be synthesized, which will result in garbage
12342 collection. We must treat this situation as if we were within
12343 the body of function so as to avoid collecting live data on the
12344 stack. */
12354 /* Restore the "this" pointer. */
12356 {
12359 }
12366 /* Make sure the default argument is reasonable. */
12372 {
12376 }
12379 }
12381 /* Substitute into all the default arguments for FN. */
12383 static void
12385 {
12386 tree arg;
12387 tree tmpl_args;
12391 /* If this function is not yet instantiated, we certainly don't need
12392 its default arguments. */
12395 /* Don't do this again for clones. */
12401 arg;
12407 complain);
12408 }
12410 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12412 static tree
12414 tree lambda_fntype)
12415 {
12420 /* Nobody should be tsubst'ing into non-template functions. */
12424 {
12425 /* If T is not dependent, just return it. */
12429 /* Calculate the most general template of which R is a
12430 specialization. */
12433 /* We're substituting a lambda function under tsubst_lambda_expr but not
12434 directly from it; find the matching function we're already inside.
12435 But don't do this if T is a generic lambda with a single level of
12436 template parms, as in that case we're doing a normal instantiation. */
12442 /* Calculate the complete set of arguments used to
12443 specialize R. */
12445 (DECL_TEMPLATE_RESULT
12451 /* Check to see if we already have this specialization. */
12453 {
12457 }
12459 /* We can see more levels of arguments than parameters if
12460 there was a specialization of a member template, like
12461 this:
12463 template <class T> struct S { template <class U> void f(); }
12464 template <> template <class U> void S<int>::f(U);
12466 Here, we'll be substituting into the specialization,
12467 because that's where we can find the code we actually
12468 want to generate, but we'll have enough arguments for
12469 the most general template.
12471 We also deal with the peculiar case:
12473 template <class T> struct S {
12474 template <class U> friend void f();
12475 };
12476 template <class U> void f() {}
12477 template S<int>;
12478 template void f<double>();
12480 Here, the ARGS for the instantiation of will be {int,
12481 double}. But, we only need as many ARGS as there are
12482 levels of template parameters in CODE_PATTERN. We are
12483 careful not to get fooled into reducing the ARGS in
12484 situations like:
12486 template <class T> struct S { template <class U> void f(U); }
12487 template <class T> template <> void S<T>::f(int) {}
12489 which we can spot because the pattern will be a
12490 specialization in this case. */
12497 }
12498 else
12499 {
12500 /* This special case arises when we have something like this:
12502 template <class T> struct S {
12503 friend void f<int>(int, double);
12504 };
12506 Here, the DECL_TI_TEMPLATE for the friend declaration
12507 will be an IDENTIFIER_NODE. We are being called from
12508 tsubst_friend_function, and we want only to create a
12509 new decl (R) with appropriate types so that we can call
12510 determine_specialization. */
12513 }
12530 /* If we hit excessive deduction depth, the type is bogus even if
12531 it isn't error_mark_node, so don't build a decl. */
12535 /* We do NOT check for matching decls pushed separately at this
12536 point, as they may not represent instantiations of this
12537 template, and in any case are considered separate under the
12538 discrete model. */
12542 /* Clear out the mangled name and RTL for the instantiation. */
12545 /* Leave DECL_INITIAL set on deleted instantiations. */
12550 /* OpenMP UDRs have the only argument a reference to the declared
12551 type. We want to diagnose if the declared type is a reference,
12552 which is invalid, but as references to references are usually
12553 quietly merged, diagnose it here. */
12555 {
12556 tree argtype
12561 "reference type %qT in "
12565 argtype);
12566 }
12569 /* Type-conversion operator. Reconstruct the name, in
12570 case it's the name of one of the template's parameters. */
12580 {
12584 }
12591 /* If this is an instantiation of a function with internal
12592 linkage, we already know what object file linkage will be
12593 assigned to the instantiation. */
12602 /* We'll re-clone as appropriate in instantiate_template. */
12605 /* If we aren't complaining now, return on error before we register
12606 the specialization so that we'll complain eventually. */
12612 /* When instantiating a constrained member, substitute
12613 into the constraints to create a new constraint. */
12616 {
12619 }
12621 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12622 this in the special friend case mentioned above where
12623 GEN_TMPL is NULL. */
12625 {
12630 tree new_r
12633 /* We instantiated this while substituting into
12634 the type earlier (template/friend54.C). */
12637 /* We're not supposed to instantiate default arguments
12638 until they are called, for a template. But, for a
12639 declaration like:
12641 template <class T> void f ()
12642 { extern void g(int i = T()); }
12644 we should do the substitution when the template is
12645 instantiated. We handle the member function case in
12646 instantiate_class_template since the default arguments
12647 might refer to other members of the class. */
12652 }
12653 else
12656 /* Copy the list of befriending classes. */
12660 {
12664 }
12667 {
12671 /* If this is an instantiation of a member template, clone it.
12672 If it isn't, that'll be handled by
12673 clone_constructors_and_destructors. */
12676 }
12687 /* Possibly limit visibility based on template args. */
12690 {
12694 }
12703 }
12705 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12707 static tree
12709 tree lambda_fntype)
12710 {
12711 /* We can get here when processing a member function template,
12712 member class template, or template template parameter. */
12715 tree spec;
12716 tree tmpl_args;
12717 tree full_args;
12718 tree r;
12722 {
12723 /* Template template parameter is treated here. */
12727 /* If we get a real template back, return it. This can happen in
12728 the context of most_specialized_partial_spec. */
12731 else
12732 /* The new TEMPLATE_DECL was built in
12733 reduce_template_parm_level. */
12736 }
12739 {
12740 /* We might already have an instance of this template.
12741 The ARGS are for the surrounding class type, so the
12742 full args contain the tsubst'd args for the context,
12743 plus the innermost args from the template decl. */
12747 /* Because this is a template, the arguments will still be
12748 dependent, even after substitution. If
12749 PROCESSING_TEMPLATE_DECL is not set, the dependency
12750 predicates will short-circuit. */
12758 /* If this is a default template template argument,
12759 tsubst might not have changed anything. */
12767 }
12769 /* Make a new template decl. It will be similar to the
12770 original, but will record the current template arguments.
12771 We also create a new function declaration, which is just
12772 like the old one, but points to this new template, rather
12773 than the old one. */
12778 // Build new template info linking to the original template decl.
12780 {
12783 }
12784 else
12787 /* The template parameters for this new template are all the
12788 template parameters for the old template, except the
12789 outermost level of parameters. */
12792 complain);
12796 {
12797 tree new_type;
12805 /* For a partial specialization, we need to keep pointing to
12806 the primary template. */
12812 }
12813 else
12814 {
12815 tree new_decl;
12819 else
12829 {
12832 }
12833 else
12834 {
12837 }
12838 }
12848 /* Record this non-type partial instantiation. */
12854 }
12856 /* True if FN is the op() for a lambda in an uninstantiated template. */
12858 bool
12860 {
12865 }
12867 /* We're instantiating a variable from template function TCTX. Return the
12868 corresponding current enclosing scope. This gets complicated because lambda
12869 functions in templates are regenerated rather than instantiated, but generic
12870 lambda functions are subsequently instantiated. */
12872 static tree
12874 {
12883 {
12896 }
12898 }
12900 /* Substitute the ARGS into the T, which is a _DECL. Return the
12901 result of the substitution. Issue error and warning messages under
12902 control of COMPLAIN. */
12904 static tree
12906 {
12907 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12908 location_t saved_loc;
12913 /* Set the filename and linenumber to improve error-reporting. */
12918 {
12928 {
12936 {
12937 /* If there is a local specialization that isn't a
12938 parameter pack, it means that we're doing a "simple"
12939 substitution from inside tsubst_pack_expansion. Just
12940 return the local specialization (which will be a single
12941 parm). */
12948 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12949 the parameters in this function parameter pack. */
12953 {
12956 /* Zero-length parameter packs are boring. Just substitute
12957 into the chain. */
12961 }
12962 else
12963 {
12964 /* All we did was update the type. Make a note of that. */
12967 }
12968 }
12970 /* Loop through all of the parameters we'll build. When T is
12971 a function parameter pack, LEN is the number of expanded
12972 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12975 {
12982 /* We're on the Ith parameter of the function parameter
12983 pack. */
12984 {
12985 /* Get the Ith type. */
12988 /* Rename the parameter to include the index. */
12991 }
12993 /* We're dealing with a normal parameter. */
13001 {
13004 else
13007 }
13017 /* Keep track of the first new parameter we
13018 generate. That's what will be returned to the
13019 caller. */
13023 /* Build a proper chain of parameters when substituting
13024 into a function parameter pack. */
13027 }
13029 /* If cp_unevaluated_operand is set, we're just looking for a
13030 single dummy parameter, so don't keep going. */
13035 /* FIRST_R contains the start of the chain we've built. */
13037 }
13041 {
13048 {
13049 /* This field is a lambda capture pack. Return a TREE_VEC of
13050 the expanded fields to instantiate_class_template_1. */
13054 {
13057 }
13058 else
13059 {
13060 /* All we did was update the type. Make a note of that. */
13063 }
13064 }
13067 {
13070 {
13074 }
13084 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13085 number of bits. */
13091 {
13092 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13093 NSDMI in perform_member_init. Still set DECL_INITIAL
13094 so that we know there is one. */
13099 }
13100 /* We don't have to set DECL_CONTEXT here; it is set by
13101 finish_member_declaration. */
13109 }
13113 }
13117 /* We reach here only for member using decls. We also need to check
13118 uses_template_parms because DECL_DEPENDENT_P is not set for a
13119 using-declaration that designates a member of the current
13120 instantiation (c++/53549). */
13123 {
13127 {
13132 {
13136 {
13139 }
13140 else
13141 {
13144 }
13146 }
13147 }
13148 else
13149 {
13155 else
13156 {
13159 }
13160 }
13161 }
13162 else
13163 {
13166 }
13171 {
13174 tree spec;
13176 tree ctx;
13185 {
13186 /* If this is the canonical decl, we don't have to
13187 mess with instantiations, and often we can't (for
13188 typename, template type parms and such). Note that
13189 TYPE_NAME is not correct for the above test if
13190 we've copied the type for a typedef. */
13196 }
13198 /* Check to see if we already have the specialization we
13199 need. */
13202 {
13203 /* T is a static data member or namespace-scope entity.
13204 We have to substitute into namespace-scope variables
13205 (not just variable templates) because of cases like:
13207 template <class T> void f() { extern T t; }
13209 where the entity referenced is not known until
13210 instantiation time. */
13214 {
13216 complain,
13218 /* If CTX is unchanged, then T is in fact the
13219 specialization we want. That situation occurs when
13220 referencing a static data member within in its own
13221 class. We can use pointer equality, rather than
13222 same_type_p, because DECL_CONTEXT is always
13223 canonical... */
13225 /* ... unless T is a member template; in which
13226 case our caller can be willing to create a
13227 specialization of that template represented
13228 by T. */
13232 }
13235 {
13240 argvec = (coerce_innermost_template_parms
13248 }
13249 }
13250 else
13251 {
13252 /* A local variable. */
13254 /* Subsequent calls to pushdecl will fill this in. */
13256 /* Unless this is a reference to a static variable from an
13257 enclosing function, in which case we need to fill it in now. */
13259 {
13263 }
13265 }
13266 /* If we already have the specialization we need, there is
13267 nothing more to do. */
13269 {
13272 }
13274 /* Create a new node for the specialization we need. */
13277 {
13280 else
13288 {
13289 /* Mask off any template args past the variable's context so we
13290 don't replace the auto with an unrelated argument. */
13294 /* This should never happen with the new lambda instantiation
13295 model, but keep the handling just in case. */
13298 }
13300 }
13302 {
13303 /* Even if the original location is out of scope, the
13304 newly substituted one is not. */
13311 {
13312 /* It may seem that this case cannot occur, since:
13314 typedef void f();
13315 void g() { f x; }
13317 declares a function, not a variable. However:
13319 typedef void f();
13320 template <typename T> void g() { T t; }
13321 template void g<f>();
13323 is an attempt to declare a variable with function
13324 type. */
13326 /* R is not yet sufficiently initialized, so we
13327 just use its name. */
13330 }
13332 /* Wait until cp_finish_decl to set this again, to handle
13333 circular dependency (template/instantiate6.C). */
13338 {
13343 {
13346 }
13348 }
13352 }
13358 /* Clear out the mangled name and RTL for the instantiation. */
13362 /* The initializer must not be expanded until it is required;
13363 see [temp.inst]. */
13367 {
13373 /* Possibly limit visibility based on template args. */
13376 {
13380 }
13382 }
13385 {
13386 /* A static data member declaration is always marked
13387 external when it is declared in-class, even if an
13388 initializer is present. We mimic the non-template
13389 processing here. */
13397 }
13398 else
13399 {
13404 }
13412 /* Preserve a typedef that names a type. */
13414 {
13418 /* An alias template specialization can be dependent
13419 even if its underlying type is not. */
13421 }
13424 }
13429 }
13430 #undef RETURN
13432 out:
13433 /* Restore the file and line information. */
13437 }
13439 /* Substitute into the ARG_TYPES of a function type.
13440 If END is a TREE_CHAIN, leave it and any following types
13441 un-substituted. */
13443 static tree
13445 tree args,
13446 tree end,
13447 tsubst_flags_t complain,
13448 tree in_decl)
13449 {
13450 tree remaining_arg_types;
13454 tree default_arg;
13465 {
13466 /* For a pack expansion, perform substitution on the
13467 entire expression. Later on, we'll handle the arguments
13468 one-by-one. */
13473 /* So that we'll spin through the parameters, one by one. */
13475 else
13476 {
13477 /* We only partially substituted into the parameter
13478 pack. Our type is TYPE_PACK_EXPANSION. */
13481 }
13482 }
13495 {
13497 {
13501 }
13503 }
13504 /* DR 657. */
13508 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13509 top-level qualifiers as required. */
13512 /* We do not substitute into default arguments here. The standard
13513 mandates that they be instantiated only when needed, which is
13514 done in build_over_call. */
13517 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13518 since the new op() won't have any associated template arguments for us
13519 to refer to later. */
13525 {
13526 /* We've instantiated a template before its default arguments
13527 have been parsed. This can happen for a nested template
13528 class, and is not an error unless we require the default
13529 argument in a call of this function. */
13530 remaining_arg_types =
13533 }
13534 else
13535 remaining_arg_types =
13537 }
13540 }
13542 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13543 *not* handle the exception-specification for FNTYPE, because the
13544 initial substitution of explicitly provided template parameters
13545 during argument deduction forbids substitution into the
13546 exception-specification:
13548 [temp.deduct]
13550 All references in the function type of the function template to the
13551 corresponding template parameters are replaced by the specified tem-
13552 plate argument values. If a substitution in a template parameter or
13553 in the function type of the function template results in an invalid
13554 type, type deduction fails. [Note: The equivalent substitution in
13555 exception specifications is done only when the function is instanti-
13556 ated, at which point a program is ill-formed if the substitution
13557 results in an invalid type.] */
13559 static tree
13561 tree args,
13562 tsubst_flags_t complain,
13563 tree in_decl)
13564 {
13565 tree return_type;
13567 tree fntype;
13569 /* The TYPE_CONTEXT is not used for function/method types. */
13572 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13573 failure. */
13577 {
13578 /* Substitute the argument types. */
13590 {
13591 /* DR 1207: 'this' is in scope in the trailing return type. */
13593 }
13595 /* Substitute the return type. */
13599 {
13602 }
13603 }
13604 else
13605 /* Substitute the return type. */
13610 /* DR 486 clarifies that creation of a function type with an
13611 invalid return type is a deduction failure. */
13614 {
13616 {
13619 else
13621 }
13623 }
13624 /* And DR 657. */
13629 {
13630 /* Substitute the argument types. */
13635 }
13637 /* Construct a new type node and return it. */
13639 {
13644 }
13645 else
13646 {
13648 /* Don't pick up extra function qualifiers from the basetype. */
13651 {
13652 /* [temp.deduct]
13654 Type deduction may fail for any of the following
13655 reasons:
13657 -- Attempting to create "pointer to member of T" when T
13658 is not a class type. */
13661 r);
13663 }
13668 }
13675 }
13677 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13678 ARGS into that specification, and return the substituted
13679 specification. If there is no specification, return NULL_TREE. */
13681 static tree
13683 tree args,
13684 tsubst_flags_t complain,
13685 tree in_decl,
13687 {
13688 tree specs;
13689 tree new_specs;
13694 {
13695 /* A noexcept-specifier. */
13700 {
13701 /* Defer instantiation of noexcept-specifiers to avoid
13702 excessive instantiations (c++/49107). */
13705 {
13706 /* We already partially instantiated this member template,
13707 so combine the new args with the old. */
13712 }
13713 else
13714 {
13717 }
13718 }
13719 else
13720 new_specs = tsubst_copy_and_build
13724 }
13726 {
13729 else
13731 {
13732 tree spec;
13737 {
13738 /* Expand the pack expansion type. */
13741 in_decl);
13747 else
13748 {
13749 /* We're substituting into a member template, so
13750 we got a TYPE_PACK_EXPANSION back. Add that
13751 expansion and move on. */
13755 expanded_specs,
13756 complain);
13759 }
13760 }
13763 {
13766 else
13771 complain);
13772 }
13775 }
13776 }
13778 }
13780 /* Take the tree structure T and replace template parameters used
13781 therein with the argument vector ARGS. IN_DECL is an associated
13782 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13783 Issue error and warning messages under control of COMPLAIN. Note
13784 that we must be relatively non-tolerant of extensions here, in
13785 order to preserve conformance; if we allow substitutions that
13786 should not be allowed, we may allow argument deductions that should
13787 not succeed, and therefore report ambiguous overload situations
13788 where there are none. In theory, we could allow the substitution,
13789 but indicate that it should have failed, and allow our caller to
13790 make sure that the right thing happens, but we don't try to do this
13791 yet.
13793 This function is used for dealing with types, decls and the like;
13794 for expressions, use tsubst_expr or tsubst_copy. */
13796 tree
13798 {
13821 else
13826 /* Reuse typedefs. We need to do this to handle dependent attributes,
13827 such as attribute aligned. */
13830 {
13834 {
13835 /* DECL represents an alias template and we want to
13836 instantiate it. */
13840 }
13844 {
13848 }
13853 else
13854 /* The typedef is from a non-template context. */
13858 {
13860 r = cp_build_qualified_type_real
13864 }
13865 else
13866 {
13867 /* We don't have an instantiation yet, so drop the typedef. */
13872 }
13873 }
13890 {
13916 {
13922 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13923 needed. */
13929 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13930 with TREE_SIDE_EFFECTS that indicates this is not an integral
13931 constant expression. */
13934 {
13937 }
13940 }
13946 {
13952 /* Early in template argument deduction substitution, we don't
13953 want to reduce the level of 'auto', or it will be confused
13954 with a normal template parm in subsequent deduction. */
13966 {
13969 /* See through ARGUMENT_PACK_SELECT arguments. */
13972 }
13977 {
13979 /* If ARG is an argument pack, we don't actually want to
13980 perform a substitution here, because substitutions
13981 for argument packs are only done
13982 element-by-element. We can get to this point when
13983 substituting the type of a non-type template
13984 parameter pack, when that type actually contains
13985 template parameter packs from an outer template, e.g.,
13987 template<typename... Types> struct A {
13988 template<Types... Values> struct B { };
13989 }; */
13993 {
13999 return cp_build_qualified_type_real
14001 }
14003 {
14004 /* We are processing a type constructed from a
14005 template template parameter. */
14016 /* Consider this code:
14018 template <template <class> class Template>
14019 struct Internal {
14020 template <class Arg> using Bind = Template<Arg>;
14021 };
14023 template <template <class> class Template, class Arg>
14024 using Instantiate = Template<Arg>; //#0
14026 template <template <class> class Template,
14027 class Argument>
14028 using Bind =
14029 Instantiate<Internal<Template>::template Bind,
14030 Argument>; //#1
14032 When #1 is parsed, the
14033 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14034 parameter `Template' in #0 matches the
14035 UNBOUND_CLASS_TEMPLATE representing the argument
14036 `Internal<Template>::template Bind'; We then want
14037 to assemble the type `Bind<Argument>' that can't
14038 be fully created right now, because
14039 `Internal<Template>' not being complete, the Bind
14040 template cannot be looked up in that context. So
14041 we need to "store" `Bind<Argument>' for later
14042 when the context of Bind becomes complete. Let's
14043 store that in a TYPENAME_TYPE. */
14047 argvec),
14048 typename_type,
14049 complain);
14051 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14052 are resolving nested-types in the signature of a
14053 member function templates. Otherwise ARG is a
14054 TEMPLATE_DECL and is the real template to be
14055 instantiated. */
14063 complain);
14064 return cp_build_qualified_type_real
14066 }
14069 else
14070 /* TEMPLATE_PARM_INDEX. */
14072 }
14075 /* This can happen during the attempted tsubst'ing in
14076 unify. This means that we don't yet have any information
14077 about the template parameter in question. */
14080 /* If we get here, we must have been looking at a parm for a
14081 more deeply nested template. Make a new version of this
14082 template parameter, but with a lower level. */
14084 {
14089 {
14091 r = cp_build_qualified_type_real
14095 }
14102 /* Break infinite recursion when substituting the constraints
14104 else
14105 {
14116 {
14117 /* Propagate constraints on placeholders. */
14122 {
14126 }
14127 }
14130 /* We have reduced the level of the template
14131 template parameter, but not the levels of its
14132 template parameters, so canonical_type_parameter
14133 will not be able to find the canonical template
14134 template parameter for this level. Thus, we
14135 require structural equality checking to compare
14136 TEMPLATE_TEMPLATE_PARMs. */
14140 else
14144 {
14146 /* We might need to substitute into the types of non-type
14147 template parameters. */
14159 }
14160 }
14164 /* OK, now substitute the type of the non-type parameter. We
14165 couldn't do it earlier because it might be an auto parameter,
14166 and we wouldn't need to if we had an argument. */
14175 }
14178 }
14181 {
14189 {
14193 }
14196 {
14200 }
14203 {
14207 }
14213 }
14216 /* We should never be tsubsting a binfo. */
14220 /* A vector of template arguments. */
14226 {
14230 /* [temp.deduct]
14232 Type deduction may fail for any of the following
14233 reasons:
14235 -- Attempting to create a pointer to reference type.
14236 -- Attempting to create a reference to a reference type or
14237 a reference to void.
14239 Core issue 106 says that creating a reference to a reference
14240 during instantiation is no longer a cause for failure. We
14241 only enforce this check in strict C++98 mode. */
14245 {
14248 /* We keep track of the last time we issued this error
14249 message to avoid spewing a ton of messages during a
14250 single bad template instantiation. */
14253 {
14258 else
14261 }
14264 }
14268 {
14270 {
14273 type);
14274 else
14276 type);
14277 }
14279 }
14281 {
14285 }
14287 /* In C++0x, during template argument substitution, when there is an
14288 attempt to create a reference to a reference type, reference
14289 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14291 "If a template-argument for a template-parameter T names a type
14292 that is a reference to a type A, an attempt to create the type
14293 'lvalue reference to cv T' creates the type 'lvalue reference to
14294 A,' while an attempt to create the type type rvalue reference to
14295 cv T' creates the type T"
14296 */
14297 r = cp_build_reference_type
14300 else
14305 /* Will this ever be needed for TYPE_..._TO values? */
14309 }
14311 {
14314 {
14315 /* [temp.deduct]
14317 Type deduction may fail for any of the following
14318 reasons:
14320 -- Attempting to create "pointer to member of T" when T
14321 is not a class type. */
14325 }
14327 {
14331 }
14333 {
14337 }
14340 {
14341 /* The type of the implicit object parameter gets its
14342 cv-qualifiers from the FUNCTION_TYPE. */
14343 tree memptr;
14344 tree method_type
14349 complain);
14350 }
14351 else
14354 complain);
14355 }
14358 {
14359 tree fntype;
14360 tree specs;
14365 /* Substitute the exception specification. */
14373 }
14375 {
14380 /* As an optimization, we avoid regenerating the array type if
14381 it will obviously be the same as T. */
14385 /* These checks should match the ones in create_array_type_for_decl.
14387 [temp.deduct]
14389 The deduction may fail for any of the following reasons:
14391 -- Attempting to create an array with an element type that
14392 is void, a function type, or a reference type, or [DR337]
14393 an abstract class type. */
14399 {
14403 }
14411 {
14414 }
14417 }
14420 {
14432 {
14436 }
14438 {
14439 /* Normally, make_typename_type does not require that the CTX
14440 have complete type in order to allow things like:
14442 template <class T> struct S { typename S<T>::X Y; };
14444 But, such constructs have already been resolved by this
14445 point, so here CTX really should have complete type, unless
14446 it's a partial instantiation. */
14449 {
14453 }
14454 }
14461 {
14464 }
14467 {
14469 {
14473 else
14475 }
14477 {
14481 else
14483 }
14484 }
14486 return cp_build_qualified_type_real
14488 }
14491 {
14503 }
14506 {
14507 tree type;
14523 complain);
14524 }
14527 {
14528 tree type;
14539 {
14541 {
14545 }
14548 }
14559 else
14560 {
14564 /* In a template ~id could be either a complement expression
14565 or an unqualified-id naming a destructor; if instantiating
14566 it produces an expression, it's not an id-expression or
14567 member access. */
14570 }
14575 }
14578 {
14582 }
14586 {
14587 tree r;
14591 else
14599 }
14614 /* We should use one of the expression tsubsts for these codes. */
14620 }
14621 }
14623 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14624 expression on the left-hand side of the "." or "->" operator. We
14625 only do the lookup if we had a dependent BASELINK. Otherwise we
14626 adjust it onto the instantiated heirarchy. */
14628 static tree
14631 {
14643 {
14650 }
14657 {
14663 /* Treat as-if non-dependent below. */
14668 {
14674 }
14678 }
14679 else
14680 /* We're going to overwrite pieces below, make a duplicate. */
14683 /* If lookup found a single function, mark it as used at this point.
14684 (If lookup found multiple functions the one selected later by
14685 overload resolution will be marked as used at that point.) */
14691 {
14692 /* Add back the template arguments, if present. */
14697 /* Update the conversion operator type. */
14699 }
14705 {
14707 qualifying_scope,
14708 object_type);
14710 /* We need to call adjust_result_of_qualified_name_lookup in case the
14711 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14712 so that we still get virtual function binding. */
14714 }
14717 }
14719 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14720 true if the qualified-id will be a postfix-expression in-and-of
14721 itself; false if more of the postfix-expression follows the
14722 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14723 of "&". */
14725 static tree
14729 {
14730 tree expr;
14731 tree scope;
14732 tree name;
14734 tree template_args;
14739 /* Figure out what name to look up. */
14742 {
14752 }
14753 else
14754 {
14757 }
14759 /* Substitute into the qualifying scope. When there are no ARGS, we
14760 are just trying to simplify a non-dependent expression. In that
14761 case the qualifying scope may be dependent, and, in any case,
14762 substituting will not help. */
14765 {
14768 }
14769 else
14773 {
14780 }
14783 {
14785 {
14786 /* A BIT_NOT_EXPR is used to represent a destructor. */
14788 {
14792 }
14793 else
14796 }
14797 else
14801 {
14803 {
14807 }
14809 }
14810 }
14813 {
14815 scope);
14816 /* Remember that there was a reference to this entity. */
14819 }
14822 {
14828 }
14831 {
14834 complain);
14835 else
14837 }
14843 {
14844 expr = (adjust_result_of_qualified_name_lookup
14846 expr = (finish_qualified_id_expr
14850 }
14852 /* Expressions do not generally have reference type. */
14854 /* However, if we're about to form a pointer-to-member, we just
14855 want the referenced member referenced. */
14863 }
14865 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14866 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14867 for tsubst. */
14869 static tree
14872 {
14879 {
14880 /* If we had an initializer but it
14881 instantiated to nothing,
14882 value-initialize the object. This will
14883 only occur when the initializer was a
14884 pack expansion where the parameter packs
14885 used in that expansion were of length
14886 zero. */
14888 complain);
14893 }
14896 }
14898 /* Like tsubst, but deals with expressions. This function just replaces
14899 template parms; to finish processing the resultant expression, use
14900 tsubst_copy_and_build or tsubst_expr. */
14902 static tree
14904 {
14906 tree r;
14914 {
14919 {
14920 /* We get here for a use of 'this' in an NSDMI. */
14924 /* This can happen for a parameter name used later in a function
14925 declaration (such as in a late-specified return type). Just
14926 make a dummy decl, since it's only used for its type. */
14929 /* Give it the template pattern as its context; its true context
14930 hasn't been instantiated yet and this is good enough for
14931 mangling. */
14933 }
14942 {
14943 tree enum_type;
14944 tree v;
14948 /* There is no need to substitute into namespace-scope
14949 enumerators. */
14952 /* If ARGS is NULL, then T is known to be non-dependent. */
14956 /* Unfortunately, we cannot just call lookup_name here.
14957 Consider:
14959 template <int I> int f() {
14960 enum E { a = I };
14961 struct S { void g() { E e = a; } };
14962 };
14964 When we instantiate f<7>::S::g(), say, lookup_name is not
14965 clever enough to find f<7>::a. */
14966 enum_type
14976 /* We didn't find the name. That should never happen; if
14977 name-lookup found it during preliminary parsing, we
14978 should find it again here during instantiation. */
14980 }
14985 {
14986 tree ctx;
14991 {
14994 {
14998 }
15000 }
15001 }
15011 {
15014 {
15015 /* First try name lookup to find the instantiation. */
15018 {
15019 /* Make sure that the one we found is the one we want. */
15023 }
15027 else
15028 {
15029 /* This can happen for a variable used in a
15030 late-specified return type of a local lambda, or for a
15031 local static or constant. Building a new VAR_DECL
15032 should be OK in all those cases. */
15035 /* Avoid infinite recursion (79640). */
15038 {
15039 /* We can't call cp_finish_decl, so handle the
15040 initializer by hand. */
15055 }
15062 }
15063 /* Remember this for subsequent uses. */
15066 }
15069 }
15070 else
15080 /* An OVERLOAD will always be a non-dependent overload set; an
15081 overload set from function scope will just be represented with an
15082 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15084 /* We must have marked any lookups as persistent. */
15100 {
15101 /* Template template argument like the following example need
15102 special treatment:
15104 template <template <class> class TT> struct C {};
15105 template <class T> struct D {
15106 template <class U> struct E {};
15107 C<E> c; // #1
15108 };
15109 D<int> d; // #2
15111 We are processing the template argument `E' in #1 for
15112 the template instantiation #2. Originally, `E' is a
15113 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15114 have to substitute this with one having context `D<int>'. */
15118 {
15119 /* When rewriting a constructor into a deduction guide, a
15120 non-dependent name can become dependent, so memtmpl<args>
15121 becomes context::template memtmpl<args>. */
15125 }
15127 }
15128 else
15129 /* Ordinary template template argument. */
15134 {
15135 /* Handle location wrappers by substituting the wrapped node
15136 first, *then* reusing the resulting type. Doing the type
15137 first ensures that we handle template parameters and
15138 parameter pack expansions. */
15142 }
15152 {
15156 }
15161 {
15170 /* We only want to compute the number of arguments. */
15173 else
15180 {
15182 /* Set TREE_USED for the benefit of -Wunused. */
15186 }
15194 {
15199 else
15205 else
15208 }
15209 else
15211 }
15213 {
15221 }
15222 /* Fall through */
15238 {
15242 }
15245 {
15246 tree object;
15247 tree name;
15252 {
15256 }
15259 {
15269 }
15274 in_decl);
15275 else
15278 }
15316 {
15320 }
15323 {
15328 }
15331 {
15335 }
15338 {
15346 }
15352 {
15359 }
15362 {
15369 }
15372 {
15379 }
15382 {
15383 /* Substituted template arguments */
15392 }
15395 {
15415 }
15440 /* Fall through. */
15443 {
15446 }
15447 else
15451 /* This is handled by tsubst_copy_and_build. */
15455 {
15459 }
15462 /* We shouldn't have built any of these during initial template
15463 generation. Instead, they should be built during instantiation
15464 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15468 {
15478 }
15496 {
15497 /* Instantiate any typedefs in the type. */
15502 }
15505 /* These can sometimes show up in a partial instantiation, but never
15506 involve template parms. */
15522 /* ??? There's no point in copying it for now, but maybe some
15523 day it will contain more information, such as a pointer back
15524 to the containing function, inlined copy or so. */
15528 /* We shouldn't get here, but keep going if !flag_checking. */
15532 }
15533 }
15535 /* Helper function for tsubst_omp_clauses, used for instantiation of
15536 OMP_CLAUSE_DECL of clauses. */
15538 static tree
15540 tree in_decl)
15541 {
15545 /* Handle an OpenMP array section represented as a TREE_LIST (or
15546 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15547 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15548 TREE_LIST. We can handle it exactly the same as an array section
15549 (purpose, value, and a chain), even though the nomenclature
15550 (low_bound, length, etc) is different. */
15552 {
15553 tree low_bound
15559 in_decl);
15568 }
15571 /* Undo convert_from_reference tsubst_expr could have called. */
15577 }
15579 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15581 static tree
15584 {
15589 {
15595 {
15598 {
15604 }
15605 /* FALLTHRU */
15620 in_decl);
15652 {
15655 {
15662 }
15663 else
15665 }
15668 in_decl);
15674 in_decl);
15682 in_decl);
15684 {
15687 }
15692 else
15695 in_decl,
15719 }
15722 {
15732 /* tsubst_expr on SCOPE_REF results in returning
15733 finish_non_static_data_member result. Undo that here. */
15737 {
15742 {
15746 CASE_CONVERT:
15755 /* FALLTHRU */
15759 }
15760 }
15766 {
15769 {
15772 }
15773 }
15777 }
15778 }
15782 {
15787 {
15790 }
15791 }
15793 }
15795 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15797 static tree
15799 tree in_decl)
15800 {
15801 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15821 {
15824 else
15825 {
15829 }
15830 }
15835 #undef RECUR
15836 }
15838 /* Used to temporarily communicate the list of #pragma omp parallel
15839 clauses to #pragma omp for instantiation if they are combined
15840 together. */
15844 /* Substitute one OMP_FOR iterator. */
15846 static void
15851 {
15852 #define RECUR(NODE) \
15853 tsubst_expr ((NODE), args, complain, in_decl, \
15854 integral_constant_expression_p)
15861 {
15864 }
15870 {
15871 /* We need to jump through some hoops to handle declarations in the
15872 init-statement, since we might need to handle auto deduction,
15873 but we need to keep control of initialization. */
15877 }
15878 else
15879 {
15881 {
15884 {
15888 {
15892 CASE_CONVERT:
15900 {
15903 }
15904 /* FALLTHRU */
15908 }
15909 }
15910 }
15911 else
15913 }
15924 {
15926 {
15927 /* Declare the variable, but don't let that initialize it. */
15932 }
15937 {
15942 }
15943 else
15950 }
15953 {
15954 /* Declare and initialize the variable. */
15957 }
15959 {
15963 {
15965 {
15971 {
15974 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15979 }
15982 {
15984 decl);
15986 }
15989 {
15991 decl);
15993 }
15994 else
15996 }
15999 }
16001 {
16006 {
16009 }
16010 }
16011 }
16014 {
16018 }
16019 else
16023 {
16034 {
16042 }
16043 else
16049 {
16055 }
16059 {
16067 }
16068 else
16074 }
16080 #undef RECUR
16081 }
16083 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16084 of OMP_TARGET's body. */
16086 static tree
16088 {
16091 {
16100 }
16102 }
16104 /* Helper function for tsubst_expr. For decomposition declaration
16105 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16106 also the corresponding decls representing the identifiers
16107 of the decomposition declaration. Return DECL if successful
16108 or error_mark_node otherwise, set *FIRST to the first decl
16109 in the list chained through DECL_CHAIN and *CNT to the number
16110 of such decls. */
16112 static tree
16116 {
16121 decl2
16126 {
16128 {
16131 }
16148 {
16151 }
16152 else
16154 }
16157 }
16159 /* Like tsubst_copy for expressions, etc. but also does semantic
16160 processing. */
16162 tree
16165 {
16166 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16167 #define RECUR(NODE) \
16168 tsubst_expr ((NODE), args, complain, in_decl, \
16169 integral_constant_expression_p)
16172 tree r;
16173 location_t loc;
16185 {
16187 {
16188 tree_stmt_iterator i;
16192 }
16207 else
16217 {
16219 tree init;
16225 {
16235 else
16237 }
16240 {
16241 /* We're in tsubst_lambda_expr, we've already inserted a new
16242 capture proxy, so look it up and register it. */
16243 tree inst;
16245 {
16246 inst = (retrieve_local_specialization
16249 }
16250 else
16251 {
16255 }
16258 }
16261 /* Don't copy the old closure; we'll create a new one in
16262 tsubst_lambda_expr. */
16264 else
16265 {
16269 {
16270 /* By marking the declaration as instantiated, we avoid
16271 trying to instantiate it. Since instantiate_decl can't
16272 handle local variables, and since we've already done
16273 all that needs to be done, that's the right thing to
16274 do. */
16279 /* Anonymous aggregates are a special case. */
16282 {
16285 {
16289 }
16291 }
16297 {
16302 }
16303 else
16304 {
16309 {
16310 /* For __PRETTY_FUNCTION__ we have to adjust the
16311 initializer. */
16315 }
16316 else
16320 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16325 {
16327 tree first;
16328 tree ndecl
16336 }
16337 else
16339 }
16340 }
16341 }
16344 }
16354 {
16358 }
16363 {
16364 /* Construct another range_for, if this is not a final
16365 substitution (for inside inside a generic lambda of a
16366 template). Otherwise convert to a regular for. */
16368 stmt = (processing_template_decl
16384 {
16388 }
16389 else
16390 {
16396 }
16402 }
16409 {
16413 }
16419 {
16423 }
16436 else
16437 {
16444 }
16450 {
16459 }
16467 else
16475 else
16496 {
16503 }
16507 {
16509 tree label;
16516 }
16522 /* Computed goto's must be tsubst'd into. On the other hand,
16523 non-computed gotos must not be; the identifier in question
16524 will have no binding. */
16526 else
16532 {
16548 }
16553 {
16558 }
16559 else
16560 {
16565 else
16572 else
16578 else
16580 }
16584 {
16588 {
16590 /* Prevent instantiate_decl from trying to instantiate
16591 this variable. We've already done all that needs to be
16592 done. */
16595 }
16600 }
16606 {
16607 /* Local classes are not independent templates; they are
16608 instantiated along with their containing function. And this
16609 way we don't have to deal with pushing out of one local class
16610 to instantiate a member of another local class. */
16611 /* Closures are handled by the LAMBDA_EXPR. */
16621 }
16625 {
16626 tree condition;
16629 condition =
16631 args,
16640 }
16646 in_decl);
16681 {
16694 in_decl);
16696 {
16703 }
16715 integral_constant_expression_p);
16726 else
16727 {
16735 }
16739 }
16744 /* FALLTHRU */
16751 in_decl);
16768 in_decl);
16779 {
16782 {
16783 /* For combined target teams, ensure the num_teams and
16784 thread_limit clause expressions are evaluated on the host,
16785 before entering the target construct. */
16786 tree c;
16792 {
16801 OMP_CLAUSE_FIRSTPRIVATE);
16805 }
16806 }
16807 }
16867 {
16872 {
16875 }
16881 }
16882 else
16883 {
16890 {
16893 }
16896 {
16901 {
16904 }
16910 }
16911 else
16912 {
16916 }
16919 }
16923 {
16929 {
16933 {
16938 }
16942 }
16943 else
16944 {
16949 }
16950 }
16954 {
16958 }
16971 /* If the first operand was a statement, we're done with it. */
16975 complain));
16989 integral_constant_expression_p));
16990 }
16993 out:
16996 #undef RECUR
16997 #undef RETURN
16998 }
17000 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17001 function. For description of the body see comment above
17002 cp_parser_omp_declare_reduction_exprs. */
17004 static void
17006 {
17012 tree_stmt_iterator tsi;
17023 {
17042 }
17044 {
17064 }
17065 }
17067 /* T is a postfix-expression that is not being used in a function
17068 call. Return the substituted version of T. */
17070 static tree
17072 tsubst_flags_t complain,
17073 tree in_decl)
17074 {
17078 else
17084 }
17086 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17087 instantiation context. Instantiating a pack expansion containing a lambda
17088 might result in multiple lambdas all based on the same lambda in the
17089 template. */
17091 tree
17093 {
17107 else
17115 {
17127 else
17132 {
17141 }
17142 else
17143 {
17149 }
17150 }
17154 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17172 else
17173 {
17174 /* Fix the type of 'this'. */
17180 {
17184 }
17185 else
17186 {
17190 }
17192 /* Let finish_function set this. */
17198 else
17199 /* Still increment function_depth so that we don't GC in the
17200 middle of an expression. */
17216 else
17219 /* The capture list was built up in reverse order; fix that now. */
17226 }
17233 }
17235 /* Like tsubst but deals with expressions and performs semantic
17236 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17238 tree
17240 tree args,
17241 tsubst_flags_t complain,
17242 tree in_decl,
17245 {
17246 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17247 #define RECUR(NODE) \
17248 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17250 integral_constant_expression_p)
17253 location_t loc;
17262 /* N3276 decltype magic only applies to calls at the top level or on the
17263 right side of a comma. */
17268 {
17271 /* Fall through. */
17273 {
17274 tree decl;
17275 cp_id_kind idk;
17280 {
17283 }
17285 /* Look up the name. */
17288 /* By convention, expressions use ERROR_MARK_NODE to indicate
17289 failure, not NULL_TREE. */
17295 integral_constant_expression_p,
17303 input_location);
17307 {
17311 }
17313 }
17316 {
17317 tree object;
17327 {
17332 }
17338 {
17341 }
17342 else
17349 else
17351 }
17354 {
17358 {
17359 /* A type conversion to reference type will be enclosed in
17360 such an indirect ref, but the substitution of the cast
17361 will have also added such an indirect ref. */
17363 }
17364 else
17372 }
17375 {
17379 }
17382 {
17386 {
17391 }
17393 /* We'll pass this to convert_nontype_argument again, we don't need
17394 to actually perform any conversion here. */
17400 flags));
17401 }
17404 {
17410 }
17417 {
17418 tree type;
17424 {
17429 }
17436 {
17454 }
17457 }
17491 else
17493 in_decl);
17528 {
17535 tree r = build_x_binary_op
17537 op0,
17539 ? ERROR_MARK
17541 op1,
17543 ? ERROR_MARK
17551 }
17554 {
17558 }
17574 /* Fall through */
17577 {
17578 tree r;
17584 {
17585 /* When there are no ARGS, we are trying to evaluate a
17586 non-dependent expression from the parser. Trying to do
17587 the substitutions may not work. */
17590 }
17591 else
17592 {
17597 else
17600 /*integral_constant_expression_p=*/
17604 }
17608 else
17612 {
17614 {
17616 {
17620 }
17621 else
17625 }
17627 }
17629 }
17632 {
17642 }
17658 {
17662 tree r = build_x_modify_expr
17665 /* TREE_NO_WARNING must be set if either the expression was
17666 parenthesized or it uses an operator such as >>= rather
17667 than plain assignment. In the former case, it was already
17668 set and must be copied. In the latter case,
17669 build_x_modify_expr sets it and it must not be reset
17670 here. */
17675 }
17680 /* Remember that there was a reference to this entity. */
17687 {
17692 tree ret;
17696 else
17697 {
17701 }
17703 /* If there was an initializer in the original tree, but it
17704 instantiated to an empty list, then we should pass a
17705 non-NULL empty vector to tell build_new that it was an
17706 empty initializer() rather than no initializer. This can
17707 only happen when the initializer is a pack expansion whose
17708 parameter packs are of length zero. */
17711 else
17712 {
17716 else
17717 {
17720 }
17721 }
17727 complain);
17735 }
17738 {
17744 complain));
17745 }
17748 {
17752 integral_constant_expression_p);
17754 op0,
17757 }
17760 {
17761 tree function;
17766 tree ret;
17769 /* Internal function with no arguments. */
17773 /* When we parsed the expression, we determined whether or
17774 not Koenig lookup should be performed. */
17777 {
17780 }
17782 {
17787 }
17789 {
17790 /* Do nothing; calling tsubst_copy_and_build on an identifier
17791 would incorrectly perform unqualified lookup again.
17793 Note that we can also have an IDENTIFIER_NODE if the earlier
17794 unqualified lookup found a member function; in that case
17795 koenig_p will be false and we do want to do the lookup
17796 again to find the instantiated member function.
17798 FIXME but doing that causes c++/15272, so we need to stop
17799 using IDENTIFIER_NODE in that situation. */
17801 }
17802 else
17803 {
17805 {
17811 }
17812 else
17817 /* Avoid error about taking the address of a constructor. */
17821 in_decl,
17823 integral_constant_expression_p);
17827 }
17832 {
17837 else
17838 {
17839 /* Expand the pack expansion and push each entry onto
17840 CALL_ARGS. */
17843 {
17848 {
17853 }
17854 }
17855 else
17856 {
17857 /* A partial substitution. Add one entry. */
17859 }
17860 }
17861 }
17863 /* We do not perform argument-dependent lookup if normal
17864 lookup finds a non-function, in accordance with the
17865 expected resolution of DR 218. */
17868 /* If lookup found a member function, the Koenig lookup is
17869 not appropriate, even if an unqualified-name was used
17870 to denote the function. */
17873 /* Only do this when substitution turns a dependent call
17874 into a non-dependent call. */
17882 {
17884 {
17885 /* For backwards compatibility and good diagnostics, try
17886 the unqualified lookup again if we aren't in SFINAE
17887 context. */
17888 tree unq = (tsubst_copy_and_build
17890 integral_constant_expression_p));
17892 {
17895 }
17898 {
17899 /* In a lambda fn, we have to be careful to not
17900 introduce new this captures. Legacy code can't
17901 be using lambdas anyway, so it's ok to be
17902 stricter. */
17907 "and no declarations were found by "
17908 "argument-dependent lookup at the point "
17915 else
17919 {
17930 {
17932 input_location);
17934 "declarations in dependent base %qT are "
17940 else
17944 }
17945 else
17947 "%qD declared here, later in the "
17950 {
17953 }
17954 }
17957 }
17958 }
17960 {
17965 }
17966 }
17968 /* Remember that there was a reference to this entity. */
17972 {
17975 }
17977 /* Put back tf_decltype for the actual call. */
17982 {
17986 {
17988 "wrong number of arguments to "
17991 }
17992 else
17994 input_location),
17999 /* Unsupported internal function with arguments. */
18001 }
18004 complain);
18006 {
18021 complain);
18022 else
18023 ret = (build_new_method_call
18028 complain));
18029 }
18030 else
18033 koenig_p,
18034 complain);
18039 {
18045 {
18051 {
18054 else
18056 /* The thunk location is not interesting. */
18058 }
18059 }
18060 }
18063 }
18066 {
18072 {
18074 {
18079 }
18080 else
18081 {
18086 }
18088 }
18089 else
18090 {
18093 }
18098 }
18101 {
18106 input_location));
18107 }
18110 {
18118 {
18119 /* We have pack expansions, so expand those and
18120 create a new list out of it. */
18123 tree chain;
18126 /* Expand the argument expressions. */
18134 /* Build the rest of the list. */
18139 /* Determine the number of arguments. */
18141 {
18144 }
18147 else
18148 {
18149 /* Since we only performed a partial substitution into
18150 the argument pack, we only RETURN (a single list
18151 node. */
18158 }
18160 /* Convert the argument vectors into a TREE_LIST */
18163 {
18164 /* Grab the Ith values. */
18165 i--;
18168 value
18172 /* Build the list (backwards). */
18174 }
18177 }
18193 }
18196 {
18197 tree object;
18198 tree object_type;
18199 tree member;
18200 tree r;
18204 /* Remember that there was a reference to this entity. */
18215 else
18221 {
18226 }
18230 {
18232 {
18237 {
18240 }
18242 {
18247 }
18248 }
18249 }
18252 {
18253 /* Lookup the template functions now that we know what the
18254 scope is. */
18262 {
18265 args);
18266 member = (adjust_result_of_qualified_name_lookup
18268 object_type));
18269 }
18270 else
18271 {
18273 input_location);
18275 }
18276 }
18280 {
18282 {
18286 else
18289 }
18291 }
18295 complain);
18299 }
18306 {
18314 tree r;
18319 /* We do not want to process the index of aggregate
18320 initializers as they are identifier nodes which will be
18321 looked up by digest_init. */
18327 {
18329 /* An identifier index is looked up in the type
18330 being initialized, not the current scope. */
18335 {
18336 /* Substitute into the pack expansion. */
18338 in_decl);
18342 ;
18344 /* Just move the argument into place. */
18346 else
18347 {
18348 /* Update the length of the final CONSTRUCTOR
18349 arguments vector, and note that we will need to
18350 copy.*/
18353 }
18354 }
18355 else
18357 }
18360 {
18365 {
18367 {
18372 }
18373 else
18375 }
18376 }
18382 {
18387 }
18391 }
18394 {
18397 {
18400 }
18401 else
18402 {
18405 }
18406 }
18411 /* Fall through */
18414 {
18416 /* ??? We're doing a subset of finish_id_expression here. */
18418 && !processing_template_decl
18419 && !cp_unevaluated_operand
18422 {
18424 /* Replace an evaluated use of the thread_local variable with
18425 a call to its wrapper. */
18427 }
18432 /* If the original type was a reference, we'll be wrapped in
18433 the appropriate INDIRECT_REF. */
18436 }
18439 {
18443 }
18446 {
18447 tree object_ptr
18454 }
18461 {
18472 }
18475 {
18481 integral_constant_expression_p);
18485 /* If the resulting list of expression statement is empty,
18486 fold it further into void_node. */
18491 }
18494 {
18498 }
18501 /* We can get here for a constant initializer of non-dependent type.
18502 FIXME stop folding in cp_parser_initializer_clause. */
18503 {
18505 complain);
18507 }
18511 integral_constant_expression_p));
18517 {
18522 complain));
18523 }
18530 /* We should only see these for location wrapper nodes, or within
18531 instantiate_non_dependent_expr (when args is NULL_TREE). */
18536 /* fallthrough. */
18539 /* Handle Objective-C++ constructs, if appropriate. */
18540 {
18541 tree subst
18546 }
18548 }
18550 #undef RECUR
18551 #undef RETURN
18552 out:
18555 }
18557 /* Verify that the instantiated ARGS are valid. For type arguments,
18558 make sure that the type's linkage is ok. For non-type arguments,
18559 make sure they are constants if they are integral or enumerations.
18560 Emit an error under control of COMPLAIN, and return TRUE on error. */
18562 static bool
18564 {
18568 {
18578 }
18580 {
18581 /* [basic.link]: A name with no linkage (notably, the name
18582 of a class or enumeration declared in a local scope)
18583 shall not be used to declare an entity with linkage.
18584 This implies that names with no linkage cannot be used as
18585 template arguments
18587 DR 757 relaxes this restriction for C++0x. */
18592 {
18593 /* DR 488 makes use of a type with no linkage cause
18594 type deduction to fail. */
18596 {
18599 else
18602 }
18604 }
18605 /* In order to avoid all sorts of complications, we do not
18606 allow variably-modified types as template arguments. */
18608 {
18612 }
18613 }
18614 /* Class template and alias template arguments should be OK. */
18616 ;
18617 /* A non-type argument of integral or enumerated type must be a
18618 constant. */
18623 {
18627 }
18629 }
18631 static bool
18633 {
18638 {
18641 }
18645 }
18647 /* We're out of SFINAE context now, so generate diagnostics for the access
18648 errors we saw earlier when instantiating D from TMPL and ARGS. */
18650 static void
18652 {
18664 }
18666 /* Instantiate the indicated variable, function, or alias template TMPL with
18667 the template arguments in TARG_PTR. */
18669 static tree
18671 {
18673 tree fndecl;
18674 tree gen_tmpl;
18675 tree spec;
18683 /* If this function is a clone, handle it specially. */
18685 {
18686 tree spec;
18687 tree clone;
18689 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18690 DECL_CLONED_FUNCTION. */
18696 /* Look for the clone. */
18700 /* We should always have found the clone by now. */
18703 }
18708 /* Check to see if we already have this specialization. */
18712 /* targ_ptr only has the innermost template args, so add the outer ones
18713 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18714 the case of a non-dependent call within a template definition). */
18715 targ_ptr = (add_outermost_template_args
18717 targ_ptr));
18719 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18720 but it doesn't seem to be on the hot path. */
18729 {
18731 {
18735 }
18737 }
18740 complain))
18743 /* We are building a FUNCTION_DECL, during which the access of its
18744 parameters and return types have to be checked. However this
18745 FUNCTION_DECL which is the desired context for access checking
18746 is not built yet. We solve this chicken-and-egg problem by
18747 deferring all checks until we have the FUNCTION_DECL. */
18750 /* Instantiation of the function happens in the context of the function
18751 template, not the context of the overload resolution we're doing. */
18753 /* If there are dependent arguments, e.g. because we're doing partial
18754 ordering, make sure processing_template_decl stays set. */
18758 {
18762 }
18768 {
18769 /* We need to determine if we're using a partial or explicit
18770 specialization now, because the type of the variable could be
18771 different. */
18777 {
18782 }
18783 }
18785 /* Substitute template parameters to obtain the specialization. */
18793 {
18796 }
18798 /* The DECL_TI_TEMPLATE should always be the immediate parent
18799 template, not the most general template. */
18803 /* Now we know the specialization, compute access previously
18804 deferred. Do no access control for inheriting constructors,
18805 as we already checked access for the inherited constructor. */
18808 {
18813 }
18816 /* If we've just instantiated the main entry point for a function,
18817 instantiate all the alternate entry points as well. We do this
18818 by cloning the instantiation of the main entry point, not by
18819 instantiating the template clones. */
18824 {
18826 {
18827 /* Remember to reinstantiate when we're out of SFINAE so the user
18828 can see the errors. */
18830 }
18832 }
18834 }
18836 /* Wrapper for instantiate_template_1. */
18838 tree
18840 {
18841 tree ret;
18846 }
18848 /* Instantiate the alias template TMPL with ARGS. Also push a template
18849 instantiation level, which instantiate_template doesn't do because
18850 functions and variables have sufficient context established by the
18851 callers. */
18853 static tree
18855 {
18862 {
18865 }
18867 args =
18875 /* We can't free this if a pending_template entry or last_error_tinst_level
18876 is pointing at it. */
18882 }
18884 /* PARM is a template parameter pack for FN. Returns true iff
18885 PARM is used in a deducible way in the argument list of FN. */
18887 static bool
18889 {
18892 {
18894 tree packs;
18900 {
18901 /* The template parameter pack is used in a function parameter
18902 pack. If this is the end of the parameter list, the
18903 template parameter pack is deducible. */
18906 else
18907 /* Otherwise, not. Well, it could be deduced from
18908 a non-pack parameter, but doing so would end up with
18909 a deduction mismatch, so don't bother. */
18911 }
18912 }
18913 /* The template parameter pack isn't used in any function parameter
18914 packs, but it might be used deeper, e.g. tuple<Args...>. */
18916 }
18918 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18919 NARGS elements of the arguments that are being used when calling
18920 it. TARGS is a vector into which the deduced template arguments
18921 are placed.
18923 Returns either a FUNCTION_DECL for the matching specialization of FN or
18924 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18925 true, diagnostics will be printed to explain why it failed.
18927 If FN is a conversion operator, or we are trying to produce a specific
18928 specialization, RETURN_TYPE is the return type desired.
18930 The EXPLICIT_TARGS are explicit template arguments provided via a
18931 template-id.
18933 The parameter STRICT is one of:
18935 DEDUCE_CALL:
18936 We are deducing arguments for a function call, as in
18937 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18938 deducing arguments for a call to the result of a conversion
18939 function template, as in [over.call.object].
18941 DEDUCE_CONV:
18942 We are deducing arguments for a conversion function, as in
18943 [temp.deduct.conv].
18945 DEDUCE_EXACT:
18946 We are deducing arguments when doing an explicit instantiation
18947 as in [temp.explicit], when determining an explicit specialization
18948 as in [temp.expl.spec], or when taking the address of a function
18949 template, as in [temp.deduct.funcaddr]. */
18951 tree
18953 tree explicit_targs,
18954 tree targs,
18957 tree return_type,
18958 unification_kind_t strict,
18962 {
18963 tree parms;
18964 tree fntype;
18977 tree tinst;
18983 full_targs = (add_outermost_template_args
18985 targs));
18990 /* In C++0x, it's possible to have a function template whose type depends
18991 on itself recursively. This is most obvious with decltype, but can also
18992 occur with enumeration scope (c++/48969). So we need to catch infinite
18993 recursion and reject the substitution at deduction time; this function
18994 will return error_mark_node for any repeated substitution.
18996 This also catches excessive recursion such as when f<N> depends on
18997 f<N-1> across all integers, and returns error_mark_node for all the
18998 substitutions back up to the initial one.
19000 This is, of course, not reentrant. */
19010 {
19011 /* [temp.deduct]
19013 The specified template arguments must match the template
19014 parameters in kind (i.e., type, nontype, template), and there
19015 must not be more arguments than there are parameters;
19016 otherwise type deduction fails.
19018 Nontype arguments must match the types of the corresponding
19019 nontype template parameters, or must be convertible to the
19020 types of the corresponding nontype parameters as specified in
19021 _temp.arg.nontype_, otherwise type deduction fails.
19023 All references in the function type of the function template
19024 to the corresponding template parameters are replaced by the
19025 specified template argument values. If a substitution in a
19026 template parameter or in the function type of the function
19027 template results in an invalid type, type deduction fails. */
19038 explicit_targs);
19040 /* Adjust any explicit template arguments before entering the
19041 substitution context. */
19042 explicit_targs
19044 complain,
19050 /* Substitute the explicit args into the function type. This is
19051 necessary so that, for instance, explicitly declared function
19052 arguments can match null pointed constants. If we were given
19053 an incomplete set of explicit args, we must not do semantic
19054 processing during substitution as we could create partial
19055 instantiations. */
19057 {
19062 /* Dig out the actual parm. */
19065 {
19068 }
19070 {
19073 }
19076 /* No explicit argument for this template parameter. */
19080 {
19081 /* Mark the argument pack as "incomplete". We could
19082 still deduce more arguments during unification.
19083 We remove this mark in type_unification_real. */
19085 {
19089 }
19091 /* We have some incomplete argument packs. */
19093 }
19094 }
19098 {
19101 }
19104 /* Ignore any access checks; we'll see them again in
19105 instantiate_template and they might have the wrong
19106 access path at this point. */
19118 /* Place the explicitly specified arguments in TARGS. */
19122 }
19124 /* Never do unification on the 'this' parameter. */
19128 {
19129 /* We're deducing for a call to the result of a template conversion
19130 function. The parms we really want are in return_type. */
19134 }
19136 {
19145 }
19147 /* We allow incomplete unification without an error message here
19148 because the standard doesn't seem to explicitly prohibit it. Our
19149 callers must be ready to deal with unification failures in any
19150 event. */
19153 /* If we aren't explaining yet, push tinst context so we can see where
19154 any errors (e.g. from class instantiations triggered by instantiation
19155 of default template arguments) come from. If we are explaining, this
19156 context is redundant. */
19158 {
19161 }
19163 /* type_unification_real will pass back any access checks from default
19164 template argument substitution. */
19176 /* Now that we have bindings for all of the template arguments,
19177 ensure that the arguments deduced for the template template
19178 parameters have compatible template parameter lists. We cannot
19179 check this property before we have deduced all template
19180 arguments, because the template parameter types of a template
19181 template parameter might depend on prior template parameters
19182 deduced after the template template parameter. The following
19183 ill-formed example illustrates this issue:
19185 template<typename T, template<T> class C> void f(C<5>, T);
19187 template<int N> struct X {};
19189 void g() {
19190 f(X<5>(), 5l); // error: template argument deduction fails
19191 }
19193 The template parameter list of 'C' depends on the template type
19194 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19195 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19196 time that we deduce 'C'. */
19199 {
19202 }
19204 /* All is well so far. Now, check:
19206 [temp.deduct]
19208 When all template arguments have been deduced, all uses of
19209 template parameters in nondeduced contexts are replaced with
19210 the corresponding deduced argument values. If the
19211 substitution results in an invalid type, as described above,
19212 type deduction fails. */
19215 {
19218 }
19220 /* Also collect access checks from the instantiation. */
19233 /* Now perform any access checks encountered during substitution. */
19240 /* If we're looking for an exact match, check that what we got
19241 is indeed an exact match. It might not be if some template
19242 parameters are used in non-deduced contexts. But don't check
19243 for an exact match if we have dependent template arguments;
19244 in that case we're doing partial ordering, and we already know
19245 that we have two candidates that will provide the actual type. */
19247 {
19251 tree sarg
19257 {
19261 }
19262 }
19264 /* After doing deduction with the inherited constructor, actually return an
19265 instantiation of the inheriting constructor. */
19271 fail:
19274 {
19276 /* Reset once we're all the way out. */
19278 }
19280 /* We can't free this if a pending_template entry or last_error_tinst_level
19281 is pointing at it. */
19287 }
19289 /* Adjust types before performing type deduction, as described in
19290 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19291 sections are symmetric. PARM is the type of a function parameter
19292 or the return type of the conversion function. ARG is the type of
19293 the argument passed to the call, or the type of the value
19294 initialized with the result of the conversion function.
19295 ARG_EXPR is the original argument expression, which may be null. */
19297 static int
19301 tree arg_expr)
19302 {
19306 {
19311 /* Swap PARM and ARG throughout the remainder of this
19312 function; the handling is precisely symmetric since PARM
19313 will initialize ARG rather than vice versa. */
19318 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19319 too, but here handle it by stripping the reference from PARM
19320 rather than by adding it to ARG. */
19328 /* Nothing else to do in this case. */
19333 }
19336 {
19337 /* [temp.deduct.call]
19339 If P is not a reference type:
19341 --If A is an array type, the pointer type produced by the
19342 array-to-pointer standard conversion (_conv.array_) is
19343 used in place of A for type deduction; otherwise,
19345 --If A is a function type, the pointer type produced by
19346 the function-to-pointer standard conversion
19347 (_conv.func_) is used in place of A for type deduction;
19348 otherwise,
19350 --If A is a cv-qualified type, the top level
19351 cv-qualifiers of A's type are ignored for type
19352 deduction. */
19357 else
19359 }
19361 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19362 reference to a cv-unqualified template parameter that does not represent a
19363 template parameter of a class template (during class template argument
19364 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19365 an lvalue, the type "lvalue reference to A" is used in place of A for type
19366 deduction. */
19373 /* try_one_overload doesn't provide an arg_expr, but
19374 functions are always lvalues. */
19378 /* [temp.deduct.call]
19380 If P is a cv-qualified type, the top level cv-qualifiers
19381 of P's type are ignored for type deduction. If P is a
19382 reference type, the type referred to by P is used for
19383 type deduction. */
19386 {
19389 }
19391 /* DR 322. For conversion deduction, remove a reference type on parm
19392 too (which has been swapped into ARG). */
19397 }
19399 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19400 template which does contain any deducible template parameters; check if
19401 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19402 unify_one_argument. */
19404 static int
19407 {
19408 tree type;
19412 else
19419 {
19423 }
19425 {
19430 }
19434 else
19436 }
19440 /* Returns true iff the expression EXPR is one from which a template
19441 argument can be deduced. In other words, if it's an undecorated
19442 use of a template non-type parameter. */
19444 static bool
19446 {
19447 /* Strip implicit conversions. */
19451 }
19453 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19454 deducible way; that is, if it has a max value of <PARM> - 1. */
19456 static bool
19458 {
19467 }
19469 /* Returns true iff the template arguments ARGS use a template parameter
19470 in a deducible way. */
19472 static bool
19474 {
19476 {
19481 else
19482 {
19489 else
19491 }
19494 }
19496 }
19498 /* Returns true iff TYPE contains any deducible references to template
19499 parameters, as per 14.8.2.5. */
19501 static bool
19503 {
19507 /* T
19508 cv-list T
19509 TT<T>
19510 TT<i>
19511 TT<> */
19516 /* T*
19517 T&
19518 T&& */
19522 /* T[integer-constant ]
19523 type [i] */
19528 /* T type ::*
19529 type T::*
19530 T T::*
19531 T (type ::*)()
19532 type (T::*)()
19533 type (type ::*)(T)
19534 type (T::*)(T)
19535 T (type ::*)(T)
19536 T (T::*)()
19537 T (T::*)(T) */
19540 || (uses_deducible_template_parms
19543 /* template-name <T> (where template-name refers to a class template)
19544 template-name <i> (where template-name refers to a class template) */
19551 /* type (T)
19552 T()
19553 T(T) */
19556 {
19565 }
19568 }
19570 /* Subroutine of type_unification_real and unify_pack_expansion to
19571 handle unification of a single P/A pair. Parameters are as
19572 for those functions. */
19574 static int
19578 {
19585 /* We can't deduce anything from this, but we might get all the
19586 template args from other function args. */
19589 /* Implicit conversions (Clause 4) will be performed on a function
19590 argument to convert it to the type of the corresponding function
19591 parameter if the parameter type contains no template-parameters that
19592 participate in template argument deduction. */
19595 /* For function parameters with no deducible template parameters,
19596 just return. We'll check non-dependent conversions later. */
19600 {
19602 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19603 | UNIFY_ALLOW_MORE_CV_QUAL
19617 }
19619 /* We only do these transformations if this is the top-level
19620 parameter_type_list in a call or declaration matching; in other
19621 situations (nested function declarators, template argument lists) we
19622 won't be comparing a type to an expression, and we don't do any type
19623 adjustments. */
19625 {
19627 {
19630 {
19631 /* [temp.deduct.type] A template-argument can be
19632 deduced from a pointer to function or pointer
19633 to member function argument if the set of
19634 overloaded functions does not contain function
19635 templates and at most one of a set of
19636 overloaded functions provides a unique
19637 match. */
19641 /* If a unique match was not found, this is a
19642 non-deduced context, so we still succeed. */
19644 }
19650 }
19652 arg_strict |=
19654 }
19655 else
19660 /* For deduction from an init-list we need the actual list. */
19664 }
19666 /* for_each_template_parm callback that always returns 0. */
19668 static int
19670 {
19672 }
19674 /* for_each_template_parm any_fn callback to handle deduction of a template
19675 type argument from the type of an array bound. */
19677 static int
19679 {
19687 {
19693 }
19695 /* Keep walking. */
19697 }
19699 /* Try to deduce any not-yet-deduced template type arguments from the type of
19700 an array bound. This is handled separately from unify because 14.8.2.5 says
19701 "The type of a type parameter is only deduced from an array bound if it is
19702 not otherwise deduced." */
19704 static void
19706 {
19711 }
19713 /* Most parms like fn_type_unification.
19715 If SUBR is 1, we're being called recursively (to unify the
19716 arguments of a function or method parameter of a function
19717 template).
19719 CHECKS is a pointer to a vector of access checks encountered while
19720 substituting default template arguments. */
19722 static int
19724 tree full_targs,
19725 tree xparms,
19729 unification_kind_t strict,
19733 {
19738 tree parms;
19749 /* Reset the number of non-defaulted template arguments contained
19750 in TARGS. */
19753 again:
19761 {
19766 /* For a function parameter pack that occurs at the end of the
19767 parameter-declaration-list, the type A of each remaining
19768 argument of the call is compared with the type P of the
19769 declarator-id of the function parameter pack. */
19775 /* For a function parameter pack that does not occur at the
19776 end of the parameter-declaration-list, the type of the
19777 parameter pack is a non-deduced context. */
19784 explain_p))
19786 }
19791 {
19792 /* Unify the remaining arguments with the pack expansion type. */
19793 tree argvec;
19796 /* Allocate a TREE_VEC and copy in all of the arguments */
19801 /* Copy the parameter into parmvec. */
19807 /* Advance to the end of the list of parameters. */
19809 }
19811 /* Fail if we've reached the end of the parm list, and more args
19812 are present, and the parm list isn't variadic. */
19815 /* Fail if parms are left and they don't have default values and
19816 they aren't all deduced as empty packs (c++/57397). This is
19817 consistent with sufficient_parms_p. */
19820 {
19824 do
19825 {
19828 count++;
19830 }
19834 type_pack_p);
19835 }
19838 {
19839 tsubst_flags_t complain = (explain_p
19840 ? tf_warning_or_error
19845 {
19849 /* Clear the "incomplete" flags on all argument packs now so that
19850 substituting them into later default arguments works. */
19852 {
19855 }
19863 {
19868 }
19870 /* If this is an undeduced nontype parameter that depends on
19871 a type parameter, try another pass; its type may have been
19872 deduced from a later argument than the one from which
19873 this parameter can be deduced. */
19877 {
19880 }
19882 /* Core issue #226 (C++0x) [temp.deduct]:
19884 If a template argument has not been deduced, its
19885 default template argument, if any, is used.
19887 When we are in C++98 mode, TREE_PURPOSE will either
19888 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19889 to explicitly check cxx_dialect here. */
19891 /* OK, there is a default argument. Wait until after the
19892 conversion check to do substitution. */
19895 /* If the type parameter is a parameter pack, then it will
19896 be deduced to an empty parameter pack. */
19898 {
19899 tree arg;
19902 {
19905 }
19906 else
19913 }
19916 }
19918 /* DR 1391: All parameters have args, now check non-dependent parms for
19919 convertibility. */
19923 {
19929 /* For a function parameter pack that occurs at the end of the
19930 parameter-declaration-list, the type A of each remaining
19931 argument of the call is compared with the type P of the
19932 declarator-id of the function parameter pack. */
19938 /* For a function parameter pack that does not occur at the
19939 end of the parameter-declaration-list, the type of the
19940 parameter pack is a non-deduced context. */
19949 explain_p))
19951 }
19953 /* Now substitute into the default template arguments. */
19955 {
19965 {
19966 /* When saw_undeduced == 1, substitution into parm and arg might
19967 fail or not replace all template parameters, and that's
19968 fine. */
19973 }
19986 else
19994 {
19996 /* The position of the first default template argument,
19997 is also the number of non-defaulted arguments in TARGS.
19998 Record that. */
20001 }
20002 }
20006 }
20012 }
20014 /* Subroutine of type_unification_real. Args are like the variables
20015 at the call site. ARG is an overloaded function (or template-id);
20016 we try deducing template args from each of the overloads, and if
20017 only one succeeds, we go with that. Modifies TARGS and returns
20018 true on success. */
20020 static bool
20022 tree targs,
20023 tree parm,
20024 tree arg,
20025 unification_kind_t strict,
20028 {
20035 {
20038 }
20039 else
20043 /* Handle `&x' where `x' is some static or non-static member
20044 function name. */
20050 /* Strip baselink information. */
20055 {
20056 /* If we got some explicit template args, we need to plug them into
20057 the affected templates before we try to unify, in case the
20058 explicit args will completely resolve the templates in question. */
20065 {
20078 {
20083 {
20086 }
20087 }
20090 }
20091 /* If no templates (or more than one) are fully resolved by the
20092 explicit arguments, this template-id is a non-deduced context; it
20093 could still be OK if we deduce all template arguments for the
20094 enclosing call through other arguments. */
20097 }
20100 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20101 -- but the deduction does not succeed because the expression is
20102 not just the function on its own. */
20104 else
20106 {
20111 {
20114 }
20115 }
20117 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20118 to function or pointer to member function argument if the set of
20119 overloaded functions does not contain function templates and at most
20120 one of a set of overloaded functions provides a unique match.
20122 So if we found multiple possibilities, we return success but don't
20123 deduce anything. */
20126 {
20130 {
20135 /* Don't forget explicit template arguments in a pack. */
20139 }
20140 }
20145 }
20147 /* Core DR 115: In contexts where deduction is done and fails, or in
20148 contexts where deduction is not done, if a template argument list is
20149 specified and it, along with any default template arguments, identifies
20150 a single function template specialization, then the template-id is an
20151 lvalue for the function template specialization. */
20153 tree
20155 {
20168 {
20171 }
20173 {
20176 }
20178 {
20181 }
20184 {
20188 /* If we got some explicit template args, we need to plug them into
20189 the affected templates before we try to unify, in case the
20190 explicit args will completely resolve the templates in question. */
20198 {
20211 {
20214 {
20217 }
20219 {
20222 }
20223 }
20224 }
20226 {
20234 {
20235 tree base
20238 }
20242 }
20244 /* There were no good options and at least one bad one, so let the
20245 user know what the problem is. */
20247 }
20249 }
20251 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20252 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20253 different overloads deduce different arguments for a given parm.
20254 ADDR_P is true if the expression for which deduction is being
20255 performed was of the form "& fn" rather than simply "fn".
20257 Returns 1 on success. */
20259 static int
20261 tree orig_targs,
20262 tree targs,
20263 tree parm,
20264 tree arg,
20265 unification_kind_t strict,
20269 {
20271 tree tempargs;
20277 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20278 to function or pointer to member function argument if the set of
20279 overloaded functions does not contain function templates and at most
20280 one of a set of overloaded functions provides a unique match.
20282 So if this is a template, just return success. */
20294 /* We don't copy orig_targs for this because if we have already deduced
20295 some template args from previous args, unify would complain when we
20296 try to deduce a template parameter for the same argument, even though
20297 there isn't really a conflict. */
20304 /* First make sure we didn't deduce anything that conflicts with
20305 explicitly specified args. */
20307 {
20314 /* Since we're unifying against ourselves, we will fill in
20315 template args used in the function parm list with our own
20316 template parms. Discard them. */
20319 {
20320 /* Check that the argument at each index of the deduced argument pack
20321 is equivalent to the corresponding explicitly specified argument.
20322 We may have deduced more arguments than were explicitly specified,
20323 and that's OK. */
20325 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20326 that's wrong if we deduce the same argument pack from multiple
20327 function arguments: it's only incomplete the first time. */
20340 }
20343 }
20346 {
20351 }
20354 }
20356 /* PARM is a template class (perhaps with unbound template
20357 parameters). ARG is a fully instantiated type. If ARG can be
20358 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20359 TARGS are as for unify. */
20361 static tree
20364 {
20365 tree copy_of_targs;
20375 /* We need to make a new template argument vector for the call to
20376 unify. If we used TARGS, we'd clutter it up with the result of
20377 the attempted unification, even if this class didn't work out.
20378 We also don't want to commit ourselves to all the unifications
20379 we've already done, since unification is supposed to be done on
20380 an argument-by-argument basis. In other words, consider the
20381 following pathological case:
20383 template <int I, int J, int K>
20384 struct S {};
20386 template <int I, int J>
20387 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20389 template <int I, int J, int K>
20390 void f(S<I, J, K>, S<I, I, I>);
20392 void g() {
20393 S<0, 0, 0> s0;
20394 S<0, 1, 2> s2;
20396 f(s0, s2);
20397 }
20399 Now, by the time we consider the unification involving `s2', we
20400 already know that we must have `f<0, 0, 0>'. But, even though
20401 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20402 because there are two ways to unify base classes of S<0, 1, 2>
20403 with S<I, I, I>. If we kept the already deduced knowledge, we
20404 would reject the possibility I=1. */
20408 {
20412 }
20414 /* If unification failed, we're done. */
20420 }
20422 /* Given a template type PARM and a class type ARG, find the unique
20423 base type in ARG that is an instance of PARM. We do not examine
20424 ARG itself; only its base-classes. If there is not exactly one
20425 appropriate base class, return NULL_TREE. PARM may be the type of
20426 a partial specialization, as well as a plain template type. Used
20427 by unify. */
20429 static enum template_base_result
20432 {
20434 tree binfo;
20440 {
20441 /* The type could not be completed. */
20444 }
20446 /* Walk in inheritance graph order. The search order is not
20447 important, and this avoids multiple walks of virtual bases. */
20449 {
20454 {
20455 /* If there is more than one satisfactory baseclass, then:
20457 [temp.deduct.call]
20459 If they yield more than one possible deduced A, the type
20460 deduction fails.
20462 applies. */
20464 {
20467 }
20470 }
20471 }
20475 }
20477 /* Returns the level of DECL, which declares a template parameter. */
20479 static int
20481 {
20483 {
20493 }
20495 }
20497 /* Decide whether ARG can be unified with PARM, considering only the
20498 cv-qualifiers of each type, given STRICT as documented for unify.
20499 Returns nonzero iff the unification is OK on that basis. */
20501 static int
20503 {
20509 {
20510 /* Although a CVR qualifier is ignored when being applied to a
20511 substituted template parameter ([8.3.2]/1 for example), that
20512 does not allow us to unify "const T" with "int&" because both
20513 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20514 It is ok when we're allowing additional CV qualifiers
20515 at the outer level [14.8.2.1]/3,1st bullet. */
20525 }
20536 }
20538 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20539 void
20541 {
20545 {
20548 }
20549 else
20550 {
20553 }
20554 }
20556 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20557 do { \
20558 if (unify (TP, TA, P, A, S, EP)) \
20559 return 1; \
20560 } while (0)
20562 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20563 expansion at the end of PACKED_PARMS. Returns 0 if the type
20564 deduction succeeds, 1 otherwise. STRICT is the same as in
20565 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20566 function call argument list. We'll need to adjust the arguments to make them
20567 types. SUBR tells us if this is from a recursive call to
20568 type_unification_real, or for comparing two template argument
20569 lists. */
20571 static int
20575 {
20576 tree parm
20582 /* Add in any args remembered from an earlier partial instantiation. */
20590 /* Determine the parameter packs we will be deducing from the
20591 pattern, and record their current deductions. */
20594 {
20598 /* Determine the index and level of this parameter pack. */
20603 /* Keep track of the parameter packs and their corresponding
20604 argument packs. */
20607 }
20609 /* Loop through all of the arguments that have not yet been
20610 unified and unify each with the pattern. */
20612 {
20613 tree parm;
20617 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20618 or the element of its argument pack at the current index if
20619 this argument was explicitly specified. */
20621 {
20630 {
20633 }
20635 }
20637 /* If we had explicit template arguments, substitute them into the
20638 pattern before deduction. */
20640 {
20641 /* Some arguments might still be unspecified or dependent. */
20649 NULL_TREE);
20654 }
20655 else
20658 /* Unify the pattern with the current argument. */
20660 explain_p))
20663 /* For each parameter pack, collect the deduced value. */
20665 {
20671 }
20672 }
20674 /* Verify that the results of unification with the parameter packs
20675 produce results consistent with what we've seen before, and make
20676 the deduced argument packs available. */
20678 {
20685 /* By default keep the original deduced argument pack.
20686 If necessary, more specific code is going to update the
20687 resulting deduced argument later down in this function. */
20691 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20692 actually deduce anything. */
20700 {
20701 /* If we had fewer function args than explicit template args,
20702 just use the explicits. */
20707 }
20710 {
20711 tree result;
20712 /* Build the deduced *_ARGUMENT_PACK. */
20714 {
20717 }
20718 else
20723 /* Note the deduced argument packs for this parameter
20724 pack. */
20726 }
20730 {
20731 /* We only had the explicitly-provided arguments before, but
20732 now we have a complete set of arguments. */
20738 }
20739 else
20740 {
20746 /* Inconsistent unification of this parameter pack. */
20748 bad_old_arg,
20749 bad_new_arg);
20750 }
20751 }
20754 }
20756 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20757 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20758 parameters and return value are as for unify. */
20760 static int
20764 {
20765 tree parm_max;
20766 tree arg_max;
20770 /* Our representation of array types uses "N - 1" as the
20771 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20772 not an integer constant. We cannot unify arbitrarily
20773 complex expressions, so we eliminate the MINUS_EXPRs
20774 here. */
20778 {
20781 }
20785 {
20786 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20787 trying to unify the type of a variable with the type
20788 of a template parameter. For example:
20790 template <unsigned int N>
20791 void f (char (&) [N]);
20792 int g();
20793 void h(int i) {
20794 char a[g(i)];
20795 f(a);
20796 }
20798 Here, the type of the ARG will be "int [g(i)]", and
20799 may be a SAVE_EXPR, etc. */
20803 }
20805 /* If only one of the bounds used a MINUS_EXPR, compensate
20806 by adding one to the other bound. */
20809 integer_type_node,
20810 parm_max,
20811 integer_one_node);
20814 integer_type_node,
20815 arg_max,
20816 integer_one_node);
20820 }
20822 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20826 static pa_kind_t
20828 {
20837 else
20839 }
20841 /* Deduce the value of template parameters. TPARMS is the (innermost)
20842 set of template parameters to a template. TARGS is the bindings
20843 for those template parameters, as determined thus far; TARGS may
20844 include template arguments for outer levels of template parameters
20845 as well. PARM is a parameter to a template function, or a
20846 subcomponent of that parameter; ARG is the corresponding argument.
20847 This function attempts to match PARM with ARG in a manner
20848 consistent with the existing assignments in TARGS. If more values
20849 are deduced, then TARGS is updated.
20851 Returns 0 if the type deduction succeeds, 1 otherwise. The
20852 parameter STRICT is a bitwise or of the following flags:
20854 UNIFY_ALLOW_NONE:
20855 Require an exact match between PARM and ARG.
20856 UNIFY_ALLOW_MORE_CV_QUAL:
20857 Allow the deduced ARG to be more cv-qualified (by qualification
20858 conversion) than ARG.
20859 UNIFY_ALLOW_LESS_CV_QUAL:
20860 Allow the deduced ARG to be less cv-qualified than ARG.
20861 UNIFY_ALLOW_DERIVED:
20862 Allow the deduced ARG to be a template base class of ARG,
20863 or a pointer to a template base class of the type pointed to by
20864 ARG.
20865 UNIFY_ALLOW_INTEGER:
20866 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20867 case for more information.
20868 UNIFY_ALLOW_OUTER_LEVEL:
20869 This is the outermost level of a deduction. Used to determine validity
20870 of qualification conversions. A valid qualification conversion must
20871 have const qualified pointers leading up to the inner type which
20872 requires additional CV quals, except at the outer level, where const
20873 is not required [conv.qual]. It would be normal to set this flag in
20874 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20875 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20876 This is the outermost level of a deduction, and PARM can be more CV
20877 qualified at this point.
20878 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20879 This is the outermost level of a deduction, and PARM can be less CV
20880 qualified at this point. */
20882 static int
20885 {
20887 tree targ;
20888 tree tparm;
20890 tsubst_flags_t complain = (explain_p
20891 ? tf_warning_or_error
20894 /* I don't think this will do the right thing with respect to types.
20895 But the only case I've seen it in so far has been array bounds, where
20896 signedness is the only information lost, and I think that will be
20897 okay. */
20905 /* We can't deduce anything from this, but we might get all the
20906 template args from other function args. */
20912 /* If PARM uses template parameters, then we can't bail out here,
20913 even if ARG == PARM, since we won't record unifications for the
20914 template parameters. We might need them if we're trying to
20915 figure out which of two things is more specialized. */
20919 /* Handle init lists early, so the rest of the function can assume
20920 we're dealing with a type. */
20922 {
20927 /* Replace T with std::initializer_list<T> for deduction. */
20934 /* We can only deduce from an initializer list argument if the
20935 parameter is std::initializer_list or an array; otherwise this
20936 is a non-deduced context. */
20941 else
20942 {
20944 /* Deduction is defined in terms of a single type, so just punt
20945 on the (bizarre) std::initializer_list<T...>. */
20948 }
20951 {
20958 {
20962 /* It should only be possible to get here for a call. */
20964 elt_strict |= maybe_adjust_types_for_deduction
20967 }
20970 explain_p);
20971 }
20975 {
20976 /* Also deduce from the length of the initializer list. */
20983 }
20985 /* If the std::initializer_list<T> deduction worked, replace the
20986 deduced A with std::initializer_list<A>. */
20988 {
20993 }
20995 }
20997 /* If parm and arg aren't the same kind of thing (template, type, or
20998 expression), fail early. */
21002 /* Immediately reject some pairs that won't unify because of
21003 cv-qualification mismatches. */
21006 /* It is the elements of the array which hold the cv quals of an array
21007 type, and the elements might be template type parms. We'll check
21008 when we recurse. */
21010 /* We check the cv-qualifiers when unifying with template type
21011 parameters below. We want to allow ARG `const T' to unify with
21012 PARM `T' for example, when computing which of two templates
21013 is more specialized, for example. */
21027 {
21031 /* In a type which contains a nested-name-specifier, template
21032 argument values cannot be deduced for template parameters used
21033 within the nested-name-specifier. */
21045 /* The PARM is not one we're trying to unify. Just check
21046 to see if it matches ARG. */
21047 {
21052 else
21054 }
21061 /* Check for mixed types and values. */
21069 {
21072 {
21073 /* First try to match ARG directly. */
21075 explain_p);
21077 {
21078 /* Otherwise, look for a suitable base of ARG, as below. */
21085 }
21086 }
21087 /* ARG must be constructed from a template class or a template
21088 template parameter. */
21093 /* Deduce arguments T, i from TT<T> or TT<i>. */
21099 /* Fall through to deduce template name. */
21100 }
21104 {
21105 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21107 /* Simple cases: Value already set, does match or doesn't. */
21112 }
21113 else
21114 {
21115 /* If PARM is `const T' and ARG is only `int', we don't have
21116 a match unless we are allowing additional qualification.
21117 If ARG is `const int' and PARM is just `T' that's OK;
21118 that binds `const int' to `T'. */
21123 /* Consider the case where ARG is `const volatile int' and
21124 PARM is `const T'. Then, T should be `volatile int'. */
21125 arg = cp_build_qualified_type_real
21130 /* Simple cases: Value already set, does match or doesn't. */
21136 /* Make sure that ARG is not a variable-sized array. (Note
21137 that were talking about variable-sized arrays (like
21138 `int[n]'), rather than arrays of unknown size (like
21139 `int[]').) We'll get very confused by such a type since
21140 the bound of the array is not constant, and therefore
21141 not mangleable. Besides, such types are not allowed in
21142 ISO C++, so we can do as we please here. We do allow
21143 them for 'auto' deduction, since that isn't ABI-exposed. */
21147 /* Strip typedefs as in convert_template_argument. */
21149 }
21151 /* If ARG is a parameter pack or an expansion, we cannot unify
21152 against it unless PARM is also a parameter pack. */
21157 /* If the argument deduction results is a METHOD_TYPE,
21158 then there is a problem.
21159 METHOD_TYPE doesn't map to any real C++ type the result of
21160 the deduction can not be of that type. */
21174 {
21175 /* The PARM is not one we're trying to unify. Just check
21176 to see if it matches ARG. */
21182 }
21188 {
21192 /* We're deducing from an array bound, the type doesn't matter. */
21198 }
21200 /* [temp.deduct.type] If, in the declaration of a function template
21201 with a non-type template-parameter, the non-type
21202 template-parameter is used in an expression in the function
21203 parameter-list and, if the corresponding template-argument is
21204 deduced, the template-argument type shall match the type of the
21205 template-parameter exactly, except that a template-argument
21206 deduced from an array bound may be of any integral type.
21207 The non-type parameter might use already deduced type parameters. */
21212 {
21216 }
21219 /* Template-parameter dependent expression. Just accept it for now.
21220 It will later be processed in convert_template_argument. */
21221 ;
21227 /* Convert the ARG to the type of PARM; the deduced non-type
21228 template argument must exactly match the types of the
21229 corresponding parameter. */
21232 {
21233 /* We haven't deduced the type of this parameter yet. */
21235 /* We deduce from array bounds in try_array_deduction. */
21237 {
21238 /* Deduce it from the non-type argument. */
21243 }
21244 else
21245 /* Try again later. */
21247 }
21248 else
21251 /* If ARG is a parameter pack or an expansion, we cannot unify
21252 against it unless PARM is also a parameter pack. */
21257 {
21260 }
21265 {
21266 /* A pointer-to-member constant can be unified only with
21267 another constant. */
21271 /* Just unify the class member. It would be useless (and possibly
21272 wrong, depending on the strict flags) to unify also
21273 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21274 arg refer to the same variable, even if through different
21275 classes. For instance:
21277 struct A { int x; };
21278 struct B : A { };
21280 Unification of &A::x and &B::x must succeed. */
21283 }
21286 {
21290 /* [temp.deduct.call]
21292 A can be another pointer or pointer to member type that can
21293 be converted to the deduced A via a qualification
21294 conversion (_conv.qual_).
21296 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21297 This will allow for additional cv-qualification of the
21298 pointed-to types if appropriate. */
21301 /* The derived-to-base conversion only persists through one
21302 level of pointers. */
21307 }
21339 /* We have already checked cv-qualification at the top of the
21340 function. */
21344 /* As far as unification is concerned, this wins. Later checks
21345 will invalidate it if necessary. */
21348 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21349 /* Type INTEGER_CST can come from ordinary constant template args. */
21361 {
21371 /* Check for pack expansions in the parameters. */
21373 {
21375 {
21377 /* We can unify against something with a trailing
21378 parameter pack. */
21380 else
21381 /* [temp.deduct.type]/9: If the template argument list of
21382 P contains a pack expansion that is not the last
21383 template argument, the entire template argument list
21384 is a non-deduced context. */
21386 }
21387 }
21389 /* If we don't have enough arguments to satisfy the parameters
21390 (not counting the pack expression at the end), or we have
21391 too many arguments for a parameter list that doesn't end in
21392 a pack expression, we can't unify. */
21398 /* Unify all of the parameters that precede the (optional)
21399 pack expression. */
21401 {
21406 }
21409 DEDUCE_EXACT,
21412 }
21420 {
21428 }
21433 {
21437 {
21438 /* First, we try to unify the PARM and ARG directly. */
21443 {
21444 /* Fallback to the special case allowed in
21445 [temp.deduct.call]:
21447 If P is a class, and P has the form
21448 template-id, then A can be a derived class of
21449 the deduced A. Likewise, if P is a pointer to
21450 a class of the form template-id, A can be a
21451 pointer to a derived class pointed to by the
21452 deduced A. */
21458 {
21459 /* Don't give the derived diagnostic if we're
21460 already dealing with the same template. */
21461 bool same_template
21467 }
21468 }
21469 }
21473 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21474 Then, we should unify `int' and `U'. */
21476 else
21477 /* There's no chance of unification succeeding. */
21482 }
21489 {
21492 tree a;
21498 /* CV qualifications for methods can never be deduced, they must
21499 match exactly. We need to check them explicitly here,
21500 because type_unification_real treats them as any other
21501 cv-qualified parameter. */
21503 && (!check_cv_quals_for_unify
21531 {
21543 }
21546 }
21549 /* Unify a pointer to member with a pointer to member function, which
21550 deduces the type of the member as a function type. */
21552 {
21553 /* Check top-level cv qualifiers */
21561 /* Determine the type of the function we are unifying against. */
21565 }
21584 /* Matched cases are handled by the ARG == PARM test above. */
21588 /* We might get a variable as a non-type template argument in parm if the
21589 corresponding parameter is type-dependent. Make any necessary
21590 adjustments based on whether arg is a reference. */
21594 {
21599 }
21600 /* Now use the normal expression code to check whether they match. */
21611 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21612 or UNDERLYING_TYPE nodes. */
21616 /* Unification fails if we hit an error node. */
21621 {
21631 }
21632 /* FALLTHRU */
21635 /* An unresolved overload is a nondeduced context. */
21639 expr:
21640 /* We must be looking at an expression. This can happen with
21641 something like:
21643 template <int I>
21644 void foo(S<I>, S<I + 2>);
21646 This is a "nondeduced context":
21648 [deduct.type]
21650 The nondeduced contexts are:
21652 --A type that is a template-id in which one or more of
21653 the template-arguments is an expression that references
21654 a template-parameter.
21656 In these cases, we assume deduction succeeded, but don't
21657 actually infer any unifications. */
21662 else
21664 }
21665 }
21666 #undef RECUR_AND_CHECK_FAILURE
21667 \f
21668 /* Note that DECL can be defined in this translation unit, if
21669 required. */
21671 static void
21673 {
21674 tree clone;
21678 }
21680 /* Called if RESULT is explicitly instantiated, or is a member of an
21681 explicitly instantiated class. */
21683 void
21685 {
21688 /* If this entity has already been written out, it's too late to
21689 make any modifications. */
21693 /* For anonymous namespace we don't need to do anything. */
21695 {
21698 }
21701 /* The TREE_PUBLIC flag for function declarations will have been
21702 set correctly by tsubst. */
21705 /* This might have been set by an earlier implicit instantiation. */
21710 else
21711 {
21714 /* Always make artificials weak. */
21717 /* For WIN32 we also want to put explicit instantiations in
21718 linkonce sections. */
21721 }
21723 /* If EXTERN_P, then this function will not be emitted -- unless
21724 followed by an explicit instantiation, at which point its linkage
21725 will be adjusted. If !EXTERN_P, then this function will be
21726 emitted here. In neither circumstance do we want
21727 import_export_decl to adjust the linkage. */
21729 }
21731 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21732 important template arguments. If any are missing, we check whether
21733 they're important by using error_mark_node for substituting into any
21734 args that were used for partial ordering (the ones between ARGS and END)
21735 and seeing if it bubbles up. */
21737 static bool
21739 {
21744 {
21747 }
21749 {
21753 }
21755 }
21757 /* Given two function templates PAT1 and PAT2, return:
21759 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21760 -1 if PAT2 is more specialized than PAT1.
21761 0 if neither is more specialized.
21763 LEN indicates the number of parameters we should consider
21764 (defaulted parameters should not be considered).
21766 The 1998 std underspecified function template partial ordering, and
21767 DR214 addresses the issue. We take pairs of arguments, one from
21768 each of the templates, and deduce them against each other. One of
21769 the templates will be more specialized if all the *other*
21770 template's arguments deduce against its arguments and at least one
21771 of its arguments *does* *not* deduce against the other template's
21772 corresponding argument. Deduction is done as for class templates.
21773 The arguments used in deduction have reference and top level cv
21774 qualifiers removed. Iff both arguments were originally reference
21775 types *and* deduction succeeds in both directions, an lvalue reference
21776 wins against an rvalue reference and otherwise the template
21777 with the more cv-qualified argument wins for that pairing (if
21778 neither is more cv-qualified, they both are equal). Unlike regular
21779 deduction, after all the arguments have been deduced in this way,
21780 we do *not* verify the deduced template argument values can be
21781 substituted into non-deduced contexts.
21783 The logic can be a bit confusing here, because we look at deduce1 and
21784 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21785 can find template arguments for pat1 to make arg1 look like arg2, that
21786 means that arg2 is at least as specialized as arg1. */
21788 int
21790 {
21803 /* Remove the this parameter from non-static member functions. If
21804 one is a non-static member function and the other is not a static
21805 member function, remove the first parameter from that function
21806 also. This situation occurs for operator functions where we
21807 locate both a member function (with this pointer) and non-member
21808 operator (with explicit first operand). */
21810 {
21815 }
21817 {
21820 {
21821 len--;
21823 }
21824 }
21826 /* If only one is a conversion operator, they are unordered. */
21830 /* Consider the return type for a conversion function */
21832 {
21835 len++;
21836 }
21838 processing_template_decl++;
21844 /* Stop when an ellipsis is seen. */
21846 {
21857 {
21858 /* When both arguments are pack expansions, we need only
21859 unify the patterns themselves. */
21863 /* This is the last comparison we need to do. */
21865 }
21867 /* DR 1847: If a particular P contains no template-parameters that
21868 participate in template argument deduction, that P is not used to
21869 determine the ordering. */
21875 {
21879 }
21882 {
21886 }
21892 {
21898 /* Setup the parameter vector, which contains only ARG1. */
21901 /* Setup the argument vector, which contains the remaining
21902 arguments. */
21911 /* We cannot deduce in the other direction, because ARG1 is
21912 a pack expansion but ARG2 is not. */
21914 }
21916 {
21922 /* Setup the parameter vector, which contains only ARG1. */
21925 /* Setup the argument vector, which contains the remaining
21926 arguments. */
21935 /* We cannot deduce in the other direction, because ARG2 is
21936 a pack expansion but ARG1 is not.*/
21938 }
21940 else
21941 {
21942 /* The normal case, where neither argument is a pack
21943 expansion. */
21950 }
21952 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21953 arg2, then arg2 is not as specialized as arg1. */
21959 /* "If, for a given type, deduction succeeds in both directions
21960 (i.e., the types are identical after the transformations above)
21961 and both P and A were reference types (before being replaced with
21962 the type referred to above):
21963 - if the type from the argument template was an lvalue reference and
21964 the type from the parameter template was not, the argument type is
21965 considered to be more specialized than the other; otherwise,
21966 - if the type from the argument template is more cv-qualified
21967 than the type from the parameter template (as described above),
21968 the argument type is considered to be more specialized than the other;
21969 otherwise,
21970 - neither type is more specialized than the other." */
21973 {
21975 {
21978 else
21980 }
21982 {
21987 }
21988 }
21991 /* We've failed to deduce something in either direction.
21992 These must be unordered. */
21995 next:
21999 /* We have already processed all of the arguments in our
22000 handing of the pack expansion type. */
22005 }
22007 /* "In most cases, all template parameters must have values in order for
22008 deduction to succeed, but for partial ordering purposes a template
22009 parameter may remain without a value provided it is not used in the
22010 types being used for partial ordering."
22012 Thus, if we are missing any of the targs1 we need to substitute into
22013 origs1, then pat2 is not as specialized as pat1. This can happen when
22014 there is a nondeduced context. */
22020 processing_template_decl--;
22022 /* If both deductions succeed, the partial ordering selects the more
22023 constrained template. */
22025 {
22030 }
22032 /* All things being equal, if the next argument is a pack expansion
22033 for one function but not for the other, prefer the
22034 non-variadic function. FIXME this is bogus; see c++/41958. */
22038 {
22041 }
22047 else
22049 }
22051 /* Determine which of two partial specializations of TMPL is more
22052 specialized.
22054 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22055 to the first partial specialization. The TREE_PURPOSE is the
22056 innermost set of template parameters for the partial
22057 specialization. PAT2 is similar, but for the second template.
22059 Return 1 if the first partial specialization is more specialized;
22060 -1 if the second is more specialized; 0 if neither is more
22061 specialized.
22063 See [temp.class.order] for information about determining which of
22064 two templates is more specialized. */
22066 static int
22068 {
22069 tree targs;
22078 /* Just like what happens for functions, if we are ordering between
22079 different template specializations, we may encounter dependent
22080 types in the arguments, and we need our dependency check functions
22081 to behave correctly. */
22085 {
22088 }
22092 {
22095 }
22098 /* If both deductions succeed, the partial ordering selects the more
22099 constrained template. */
22103 /* In the case of a tie where at least one of the templates
22104 has a parameter pack at the end, the template with the most
22105 non-packed parameters wins. */
22107 && any_deductions
22110 {
22116 /* We don't count the pack expansion at the end. */
22126 }
22129 }
22131 /* Return the template arguments that will produce the function signature
22132 DECL from the function template FN, with the explicit template
22133 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22134 also match. Return NULL_TREE if no satisfactory arguments could be
22135 found. */
22137 static tree
22139 {
22143 tree decl_arg_types;
22146 tree arg;
22150 /* Never do unification on the 'this' parameter. */
22171 }
22173 /* Return the innermost template arguments that, when applied to a partial
22174 specialization SPEC_TMPL of TMPL, yield the ARGS.
22176 For example, suppose we have:
22178 template <class T, class U> struct S {};
22179 template <class T> struct S<T*, int> {};
22181 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22182 partial specialization and the ARGS will be {double*, int}. The resulting
22183 vector will be {double}, indicating that `T' is bound to `double'. */
22185 static tree
22187 {
22189 tree spec_args
22192 tree deduced_args;
22193 tree innermost_deduced_args;
22197 {
22201 innermost_deduced_args);
22202 }
22203 else
22207 again:
22216 {
22218 {
22224 }
22226 }
22230 {
22233 }
22235 /* Verify that nondeduced template arguments agree with the type
22236 obtained from argument deduction.
22238 For example:
22240 struct A { typedef int X; };
22241 template <class T, class U> struct C {};
22242 template <class T> struct C<T, typename T::X> {};
22244 Then with the instantiation `C<A, int>', we can deduce that
22245 `T' is `A' but unify () does not check whether `typename T::X'
22246 is `int'. */
22257 /* We only need to check the innermost arguments; the other
22258 arguments will always agree. */
22263 /* Now that we have bindings for all of the template arguments,
22264 ensure that the arguments deduced for the template template
22265 parameters have compatible template parameter lists. See the use
22266 of template_template_parm_bindings_ok_p in fn_type_unification
22267 for more information. */
22272 }
22274 // Compare two function templates T1 and T2 by deducing bindings
22275 // from one against the other. If both deductions succeed, compare
22276 // constraints to see which is more constrained.
22277 static int
22279 {
22284 {
22287 }
22290 {
22293 }
22295 // If both deductions succeed, then one may be more constrained.
22300 }
22302 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22303 Return the TREE_LIST node with the most specialized template, if
22304 any. If there is no most specialized template, the error_mark_node
22305 is returned.
22307 Note that this function does not look at, or modify, the
22308 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22309 returned is one of the elements of INSTANTIATIONS, callers may
22310 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22311 and retrieve it from the value returned. */
22313 tree
22315 {
22322 {
22328 {
22329 /* Equally specialized, move to next function. If there
22330 is no next function, nothing's most specialized. */
22335 }
22336 }
22339 /* Now verify that champ is better than everything earlier in the
22340 instantiation list. */
22343 {
22346 }
22347 }
22349 processing_template_decl--;
22355 }
22357 /* If DECL is a specialization of some template, return the most
22358 general such template. Otherwise, returns NULL_TREE.
22360 For example, given:
22362 template <class T> struct S { template <class U> void f(U); };
22364 if TMPL is `template <class U> void S<int>::f(U)' this will return
22365 the full template. This function will not trace past partial
22366 specializations, however. For example, given in addition:
22368 template <class T> struct S<T*> { template <class U> void f(U); };
22370 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22371 `template <class T> template <class U> S<T*>::f(U)'. */
22373 tree
22375 {
22377 {
22380 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22381 template friend, or a FIELD_DECL for a capture pack. */
22384 }
22386 /* Look for more and more general templates. */
22388 {
22389 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22390 (See cp-tree.h for details.) */
22399 /* Stop if we run into an explicitly specialized class template. */
22406 }
22409 }
22411 /* Return the most specialized of the template partial specializations
22412 which can produce TARGET, a specialization of some class or variable
22413 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22414 a TEMPLATE_DECL node corresponding to the partial specialization, while
22415 the TREE_PURPOSE is the set of template arguments that must be
22416 substituted into the template pattern in order to generate TARGET.
22418 If the choice of partial specialization is ambiguous, a diagnostic
22419 is issued, and the error_mark_node is returned. If there are no
22420 partial specializations matching TARGET, then NULL_TREE is
22421 returned, indicating that the primary template should be used. */
22423 static tree
22425 {
22427 tree t;
22428 tree champ;
22435 {
22439 }
22441 {
22444 }
22446 {
22450 }
22451 else
22456 /* For determining which partial specialization to use, only the
22457 innermost args are interesting. */
22459 {
22462 }
22465 {
22466 tree spec_args;
22470 {
22471 /* Substitute in the template args from the enclosing class. */
22475 }
22482 {
22486 /* Keep the candidate only if the constraints are satisfied,
22487 or if we're not compiling with concepts. */
22490 {
22493 }
22494 }
22495 }
22505 {
22508 ;
22509 else
22510 {
22512 {
22515 {
22518 }
22519 }
22521 }
22522 }
22526 {
22529 {
22532 }
22533 }
22536 {
22543 else
22547 {
22552 }
22555 }
22558 }
22560 /* Explicitly instantiate DECL. */
22562 void
22564 {
22569 /* An error occurred, for which grokdeclarator has already issued
22570 an appropriate message. */
22573 {
22576 }
22582 {
22583 /* There is an asymmetry here in the way VAR_DECLs and
22584 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22585 the latter, the DECL we get back will be marked as a
22586 template instantiation, and the appropriate
22587 DECL_TEMPLATE_INFO will be set up. This does not happen for
22588 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22589 should handle VAR_DECLs as it currently handles
22590 FUNCTION_DECLs. */
22592 {
22595 }
22598 {
22601 }
22603 {
22608 }
22609 }
22611 {
22614 }
22615 else
22618 /* Check for various error cases. Note that if the explicit
22619 instantiation is valid the RESULT will currently be marked as an
22620 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22621 until we get here. */
22624 {
22625 /* DR 259 [temp.spec].
22627 Both an explicit instantiation and a declaration of an explicit
22628 specialization shall not appear in a program unless the explicit
22629 instantiation follows a declaration of the explicit specialization.
22631 For a given set of template parameters, if an explicit
22632 instantiation of a template appears after a declaration of an
22633 explicit specialization for that template, the explicit
22634 instantiation has no effect. */
22636 }
22638 {
22639 /* [temp.spec]
22641 No program shall explicitly instantiate any template more
22642 than once.
22644 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22645 the first instantiation was `extern' and the second is not,
22646 and EXTERN_P for the opposite case. */
22649 /* If an "extern" explicit instantiation follows an ordinary
22650 explicit instantiation, the template is instantiated. */
22653 }
22655 {
22658 }
22660 {
22663 }
22666 ;
22668 {
22671 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22674 }
22675 else
22683 }
22685 static void
22687 {
22693 {
22696 }
22697 }
22699 /* Called from do_type_instantiation through binding_table_foreach to
22700 do recursive instantiation for the type bound in ENTRY. */
22701 static void
22703 {
22709 }
22711 /* Perform an explicit instantiation of template class T. STORAGE, if
22712 non-null, is the RID for extern, inline or static. COMPLAIN is
22713 nonzero if this is called from the parser, zero if called recursively,
22714 since the standard is unclear (as detailed below). */
22716 void
22718 {
22728 {
22729 tree tmpl =
22733 else
22736 }
22741 {
22744 t);
22746 }
22749 {
22751 {
22753 {
22756 "ISO C++ 1998 forbids the use of %<extern%> on "
22758 }
22759 else
22761 "ISO C++ forbids the use of %qE"
22763 }
22771 else
22772 {
22774 storage);
22776 }
22777 }
22780 {
22781 /* DR 259 [temp.spec].
22783 Both an explicit instantiation and a declaration of an explicit
22784 specialization shall not appear in a program unless the explicit
22785 instantiation follows a declaration of the explicit specialization.
22787 For a given set of template parameters, if an explicit
22788 instantiation of a template appears after a declaration of an
22789 explicit specialization for that template, the explicit
22790 instantiation has no effect. */
22792 }
22794 {
22795 /* [temp.spec]
22797 No program shall explicitly instantiate any template more
22798 than once.
22800 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22801 instantiation was `extern'. If EXTERN_P then the second is.
22802 These cases are OK. */
22809 /* If we've already instantiated the template, just return now. */
22812 }
22820 /* In contrast to implicit instantiation, where only the
22821 declarations, and not the definitions, of members are
22822 instantiated, we have here:
22824 [temp.explicit]
22826 The explicit instantiation of a class template specialization
22827 implies the instantiation of all of its members not
22828 previously explicitly specialized in the translation unit
22829 containing the explicit instantiation.
22831 Of course, we can't instantiate member template classes, since we
22832 don't have any arguments for them. Note that the standard is
22833 unclear on whether the instantiation of the members are
22834 *explicit* instantiations or not. However, the most natural
22835 interpretation is that it should be an explicit
22836 instantiation. */
22840 && !static_p
22843 {
22848 }
22853 }
22855 /* Given a function DECL, which is a specialization of TMPL, modify
22856 DECL to be a re-instantiation of TMPL with the same template
22857 arguments. TMPL should be the template into which tsubst'ing
22858 should occur for DECL, not the most general template.
22860 One reason for doing this is a scenario like this:
22862 template <class T>
22863 void f(const T&, int i);
22865 void g() { f(3, 7); }
22867 template <class T>
22868 void f(const T& t, const int i) { }
22870 Note that when the template is first instantiated, with
22871 instantiate_template, the resulting DECL will have no name for the
22872 first parameter, and the wrong type for the second. So, when we go
22873 to instantiate the DECL, we regenerate it. */
22875 static void
22877 {
22878 /* The arguments used to instantiate DECL, from the most general
22879 template. */
22880 tree code_pattern;
22884 /* Make sure that we can see identifiers, and compute access
22885 correctly. */
22889 {
22890 tree decl_parm;
22891 tree pattern_parm;
22892 tree specs;
22906 specs);
22908 /* Merge parameter declarations. */
22911 pattern_parm
22915 {
22916 tree parm_type;
22917 tree attributes;
22922 NULL_TREE);
22928 {
22931 }
22934 }
22935 /* Merge any parameters that match with the function parameter
22936 pack. */
22938 {
22940 tree expanded_types;
22941 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22942 the parameters in this function parameter pack. */
22947 {
22948 tree parm_type;
22949 tree attributes;
22952 /* Rename the parameter to include the index. */
22961 {
22964 }
22966 }
22967 }
22968 /* Merge additional specifiers from the CODE_PATTERN. */
22972 }
22974 {
22984 }
22985 else
22989 }
22991 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22992 substituted to get DECL. */
22994 tree
22996 {
22999 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23000 for the instantiation. This is not always the most general
23001 template. Consider, for example:
23003 template <class T>
23004 struct S { template <class U> void f();
23005 template <> void f<int>(); };
23007 and an instantiation of S<double>::f<int>. We want TD to be the
23008 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23010 more general template. */
23012 /* We must also deal with friend templates. Given:
23014 template <class T> struct S {
23015 template <class U> friend void f() {};
23016 };
23018 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23019 so far as the language is concerned, but that's still
23020 where we get the pattern for the instantiation from. On
23021 other hand, if the definition comes outside the class, say:
23023 template <class T> struct S {
23024 template <class U> friend void f();
23025 };
23026 template <class U> friend void f() {}
23028 we don't need to look any further. That's what the check for
23029 DECL_INITIAL is for. */
23033 {
23034 /* The present template, TD, should not be a definition. If it
23035 were a definition, we should be using it! Note that we
23036 cannot restructure the loop to just keep going until we find
23037 a template with a definition, since that might go too far if
23038 a specialization was declared, but not defined. */
23040 /* Fetch the more general template. */
23042 }
23045 }
23047 /* Returns true if we need to instantiate this template instance even if we
23048 know we aren't going to emit it. */
23050 bool
23052 {
23053 /* We always instantiate inline functions so that we can inline them. An
23054 explicit instantiation declaration prohibits implicit instantiation of
23055 non-inline functions. With high levels of optimization, we would
23056 normally inline non-inline functions -- but we're not allowed to do
23057 that for "extern template" functions. Therefore, we check
23058 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23062 /* And we need to instantiate static data members so that
23063 their initializers are available in integral constant
23064 expressions. */
23067 }
23069 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23070 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23071 error, true otherwise. */
23073 bool
23075 {
23078 /* Don't instantiate a noexcept-specification from template context. */
23093 {
23099 {
23100 /* If hash_set::add returns true, the element was already there. */
23105 fn);
23107 }
23109 {
23124 }
23125 else
23135 }
23138 {
23141 else
23143 }
23146 }
23148 /* We're starting to process the function INST, an instantiation of PATTERN;
23149 add their parameters to local_specializations. */
23151 static void
23153 {
23157 {
23161 }
23163 {
23165 {
23168 }
23169 else
23170 {
23171 /* Register the (value) argument pack as a specialization of
23172 TMPL_PARM, then move on. */
23175 }
23176 }
23178 }
23180 /* Produce the definition of D, a _DECL generated from a template. If
23181 DEFER_OK is true, then we don't have to actually do the
23182 instantiation now; we just have to do it sometime. Normally it is
23183 an error if this is an explicit instantiation but D is undefined.
23184 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23185 instantiated class template. */
23187 tree
23189 {
23191 tree gen_args;
23192 tree args;
23193 tree td;
23194 tree code_pattern;
23195 tree spec;
23196 tree gen_tmpl;
23204 /* This function should only be used to instantiate templates for
23205 functions and static member variables. */
23208 /* A concept is never instantiated. */
23211 /* Variables are never deferred; if instantiation is required, they
23212 are instantiated right away. That allows for better code in the
23213 case that an expression refers to the value of the variable --
23214 if the variable has a constant value the referring expression can
23215 take advantage of that fact. */
23219 /* Don't instantiate cloned functions. Instead, instantiate the
23220 functions they cloned. */
23228 /* D has already been instantiated or explicitly specialized, so
23229 there's nothing for us to do here.
23231 It might seem reasonable to check whether or not D is an explicit
23232 instantiation, and, if so, stop here. But when an explicit
23233 instantiation is deferred until the end of the compilation,
23234 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23235 the instantiation. */
23238 /* Check to see whether we know that this template will be
23239 instantiated in some other file, as with "extern template"
23240 extension. */
23243 /* In general, we do not instantiate such templates. */
23251 /* We should already have the extra args. */
23254 /* And what's in the hash table should match D. */
23258 /* This needs to happen before any tsubsting. */
23264 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23265 for the instantiation. */
23270 {
23271 /* Look up an explicit specialization, if any. */
23275 {
23278 }
23279 }
23283 /* We should never be trying to instantiate a member of a class
23284 template or partial specialization. */
23289 /* In the case of a friend template whose definition is provided
23290 outside the class, we may have too many arguments. Drop the
23291 ones we don't need. The same is true for specializations. */
23292 args = get_innermost_template_args
23296 {
23302 }
23303 else
23304 {
23309 else
23311 }
23313 /* We may be in the middle of deferred access check. Disable it now. */
23316 /* Unless an explicit instantiation directive has already determined
23317 the linkage of D, remember that a definition is available for
23318 this entity. */
23328 /* If D is a member of an explicitly instantiated class template,
23329 and no definition is available, treat it like an implicit
23330 instantiation. */
23333 {
23334 /* Leave linkage flags alone on instantiations with anonymous
23335 visibility. */
23337 {
23340 }
23342 }
23344 /* Defer all other templates, unless we have been explicitly
23345 forbidden from doing so. */
23347 template. */
23348 ! pattern_defined
23349 /* If it's OK to postpone instantiation, do so. */
23350 || defer_ok
23351 /* If this is a static data member that will be defined
23352 elsewhere, we don't want to instantiate the entire data
23353 member, but we do want to instantiate the initializer so that
23354 we can substitute that elsewhere. */
23356 /* Handle here a deleted function too, avoid generating
23357 its body (c++/61080). */
23359 {
23360 /* The definition of the static data member is now required so
23361 we must substitute the initializer. */
23365 {
23366 tree ns;
23367 tree init;
23376 args,
23379 /* If instantiating the initializer involved instantiating this
23380 again, don't call cp_finish_decl twice. */
23382 {
23383 /* Make sure the initializer is still constant, in case of
23384 circular dependency (template/instantiate6.C). */
23385 const_init
23389 LOOKUP_ONLYCONVERTING);
23390 }
23394 }
23396 /* We restore the source position here because it's used by
23397 add_pending_template. */
23403 /* [temp.explicit]
23405 The definition of a non-exported function template, a
23406 non-exported member function template, or a non-exported
23407 member function or static data member of a class template
23408 shall be present in every translation unit in which it is
23409 explicitly instantiated. */
23413 /* If we're in unevaluated context, we just wanted to get the
23414 constant value; this isn't an odr use, so don't queue
23415 a full instantiation. */
23418 /* ??? Historically, we have instantiated inline functions, even
23419 when marked as "extern template". */
23423 }
23424 /* Tell the repository that D is available in this translation unit
23425 -- and see if it is supposed to be instantiated here. */
23427 {
23428 /* In a PCH file, despite the fact that the repository hasn't
23429 requested instantiation in the PCH it is still possible that
23430 an instantiation will be required in a file that includes the
23431 PCH. */
23434 /* Instantiate inline functions so that the inliner can do its
23435 job, even though we'll not be emitting a copy of this
23436 function. */
23439 }
23442 tree fn_context;
23453 else
23454 {
23458 }
23460 /* Mark D as instantiated so that recursive calls to
23461 instantiate_decl do not try to instantiate it again. */
23464 /* Regenerate the declaration in case the template has been modified
23465 by a subsequent redeclaration. */
23468 /* We already set the file and line above. Reset them now in case
23469 they changed as a result of calling regenerate_decl_from_template. */
23473 {
23474 tree init;
23477 /* Clear out DECL_RTL; whatever was there before may not be right
23478 since we've reset the type of the declaration. */
23482 /* The initializer is placed in DECL_INITIAL by
23483 regenerate_decl_from_template so we don't need to
23484 push/pop_access_scope again here. Pull it out so that
23485 cp_finish_decl can process it. */
23490 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23491 initializer. That function will defer actual emission until
23492 we have a chance to determine linkage. */
23495 /* Enter the scope of D so that access-checking works correctly. */
23508 }
23512 {
23513 /* Set up the list of local specializations. */
23517 /* Set up context. */
23521 else
23524 /* Some typedefs referenced from within the template code need to be
23525 access checked at template instantiation time, i.e now. These
23526 types were added to the template at parsing time. Let's get those
23527 and perform the access checks then. */
23529 args);
23531 /* Create substitution entries for the parameters. */
23534 /* Substitute into the body of the function. */
23538 else
23539 {
23544 /* Set the current input_location to the end of the function
23545 so that finish_function knows where we are. */
23546 input_location
23549 /* Remember if we saw an infinite loop in the template. */
23550 current_function_infinite_loop
23552 }
23554 /* Finish the function. */
23558 else
23559 {
23562 }
23566 }
23568 /* We're not deferring instantiation any more. */
23573 else
23579 out:
23588 }
23590 /* Run through the list of templates that we wish we could
23591 instantiate, and instantiate any we can. RETRIES is the
23592 number of times we retry pending template instantiation. */
23594 void
23596 {
23600 /* Instantiating templates may trigger vtable generation. This in turn
23601 may require further template instantiations. We place a limit here
23602 to avoid infinite loop. */
23604 {
23608 "template instantiation depth exceeds maximum of %d"
23609 " instantiating %q+D, possibly from virtual table generation"
23613 /* Pretend that we defined it. */
23616 }
23618 do
23619 {
23624 {
23629 {
23631 {
23646 }
23649 }
23650 else
23651 {
23654 {
23655 instantiation
23661 }
23665 }
23668 /* If INSTANTIATION has been instantiated, then we don't
23669 need to consider it again in the future. */
23671 else
23672 {
23675 }
23678 }
23680 }
23684 }
23686 /* Substitute ARGVEC into T, which is a list of initializers for
23687 either base class or a non-static data member. The TREE_PURPOSEs
23688 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23689 instantiate_decl. */
23691 static tree
23693 {
23698 {
23699 tree decl;
23700 tree init;
23706 {
23707 tree expr;
23708 tree arg;
23710 /* Expand the base class expansion type into separate base
23711 classes. */
23713 tf_warning_or_error,
23714 NULL_TREE);
23718 /* We'll be building separate TREE_LISTs of arguments for
23719 each base. */
23725 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23726 expand each argument in the TREE_VALUE of t. */
23733 /* VOID_TYPE_NODE is used to indicate
23734 value-initialization. */
23735 {
23738 }
23739 else
23740 {
23741 /* Substitute parameter packs into each argument in the
23742 TREE_LIST. */
23745 {
23746 tree expanded_exprs;
23748 /* Expand the argument. */
23750 expanded_exprs
23752 tf_warning_or_error,
23753 NULL_TREE);
23757 /* Prepend each of the expanded expressions to the
23758 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23760 {
23765 }
23766 }
23769 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23770 since we built them backwards. */
23772 {
23775 }
23776 }
23777 }
23780 {
23782 {
23786 }
23787 else
23788 {
23789 tree tmp;
23804 /* If we had an initializer but it instantiated to nothing,
23805 value-initialize the object. This will only occur when
23806 the initializer was a pack expansion where the parameter
23807 packs used in that expansion were of length zero. */
23810 }
23814 {
23816 decl);
23818 }
23819 /* Look for a target constructor. */
23823 {
23826 {
23830 }
23832 }
23835 {
23839 }
23840 }
23841 }
23843 }
23845 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23847 static void
23849 {
23854 else
23856 }
23858 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23859 is the instantiation (which should have been created with
23860 start_enum) and ARGS are the template arguments to use. */
23862 static void
23864 {
23865 tree e;
23871 {
23872 tree value;
23873 tree decl;
23876 /* Note that in a template enum, the TREE_VALUE is the
23877 CONST_DECL, not the corresponding INTEGER_CST. */
23882 /* Give this enumeration constant the correct access. */
23885 /* Actually build the enumerator itself. Here we're assuming that
23886 enumerators can't have dependent attributes. */
23889 }
23899 }
23901 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23902 its type -- but without substituting the innermost set of template
23903 arguments. So, innermost set of template parameters will appear in
23904 the type. */
23906 tree
23908 {
23909 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23911 }
23913 /* Return truthvalue if we're processing a template different from
23914 the last one involved in diagnostics. */
23915 bool
23917 {
23919 }
23921 /* Remember current template involved in diagnostics. */
23922 void
23924 {
23926 }
23930 {
23932 }
23934 /* Return TRUE if current_function_decl is being instantiated, false
23935 otherwise. */
23937 bool
23939 {
23942 }
23944 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23945 type. Return false for ok, true for disallowed. Issue error and
23946 inform messages under control of COMPLAIN. */
23948 static bool
23950 {
23965 /* A bound template template parm could later be instantiated to have a valid
23966 nontype parm type via an alias template. */
23972 {
23975 else
23977 type);
23978 }
23980 }
23982 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23983 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23985 static bool
23987 {
23988 tree scope;
23990 /* [temp.dep.type]
23992 A type is dependent if it is:
23994 -- a template parameter. Template template parameters are types
23995 for us (since TYPE_P holds true for them) so we handle
23996 them here. */
24000 /* -- a qualified-id with a nested-name-specifier which contains a
24001 class-name that names a dependent type or whose unqualified-id
24002 names a dependent type. */
24006 /* An alias template specialization can be dependent even if the
24007 resulting type is not. */
24011 /* -- a cv-qualified type where the cv-unqualified type is
24012 dependent.
24013 No code is necessary for this bullet; the code below handles
24014 cv-qualified types, and we don't want to strip aliases with
24015 TYPE_MAIN_VARIANT because of DR 1558. */
24016 /* -- a compound type constructed from any dependent type. */
24026 {
24027 tree arg_type;
24032 arg_type;
24037 /* A value-dependent noexcept-specifier makes the type dependent. */
24040 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24041 affect overload resolution and treating it as dependent breaks
24042 things. */
24047 }
24048 /* -- an array type constructed from any dependent type or whose
24049 size is specified by a constant expression that is
24050 value-dependent.
24052 We checked for type- and value-dependence of the bounds in
24053 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24055 {
24060 }
24062 /* -- a template-id in which either the template name is a template
24063 parameter ... */
24066 /* ... or any of the template arguments is a dependent type or
24067 an expression that is type-dependent or value-dependent. */
24069 && (any_dependent_template_arguments_p
24073 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24074 dependent; if the argument of the `typeof' expression is not
24075 type-dependent, then it should already been have resolved. */
24081 /* A template argument pack is dependent if any of its packed
24082 arguments are. */
24084 {
24090 }
24092 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24093 be template parameters. */
24100 /* The standard does not specifically mention types that are local
24101 to template functions or local classes, but they should be
24102 considered dependent too. For example:
24104 template <int I> void f() {
24105 enum E { a = I };
24106 S<sizeof (E)> s;
24107 }
24109 The size of `E' cannot be known until the value of `I' has been
24110 determined. Therefore, `E' must be considered dependent. */
24114 /* Don't use type_dependent_expression_p here, as it can lead
24115 to infinite recursion trying to determine whether a lambda
24116 nested in a lambda is dependent (c++/47687). */
24120 && (any_dependent_template_arguments_p
24124 /* Other types are non-dependent. */
24126 }
24128 /* Returns TRUE if TYPE is dependent, in the sense of
24129 [temp.dep.type]. Note that a NULL type is considered dependent. */
24131 bool
24133 {
24134 /* If there are no template parameters in scope, then there can't be
24135 any dependent types. */
24137 {
24138 /* If we are not processing a template, then nobody should be
24139 providing us with a dependent type. */
24143 }
24145 /* If the type is NULL, we have not computed a type for the entity
24146 in question; in that case, the type is dependent. */
24150 /* Erroneous types can be considered non-dependent. */
24154 /* Getting here with global_type_node means we improperly called this
24155 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24158 /* If we have not already computed the appropriate value for TYPE,
24159 do so now. */
24161 {
24164 }
24167 }
24169 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24170 lookup. In other words, a dependent type that is not the current
24171 instantiation. */
24173 bool
24175 {
24178 }
24180 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24181 an unknown base of 'this' (and is therefore instantiation-dependent). */
24183 static bool
24185 {
24202 }
24204 /* T is a SCOPE_REF; return whether we need to consider it
24205 instantiation-dependent so that we can check access at instantiation
24206 time even though we know which member it resolves to. */
24208 static bool
24210 {
24217 else
24219 }
24221 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24222 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24223 expression. */
24225 /* Note that this predicate is not appropriate for general expressions;
24226 only constant expressions (that satisfy potential_constant_expression)
24227 can be tested for value dependence. */
24229 bool
24231 {
24235 /* A type-dependent expression is also value-dependent. */
24240 {
24242 /* A dependent member function of the current instantiation. */
24246 /* A dependent member function of the current instantiation. */
24253 /* A name that has not been looked up -- must be dependent. */
24257 /* A non-type template parm. */
24261 /* A non-type template parm. */
24267 /* A constant with literal type and is initialized
24268 with an expression that is value-dependent. */
24270 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24274 {
24278 }
24287 /* These expressions are value-dependent if the type to which
24288 the cast occurs is dependent or the expression being casted
24289 is value-dependent. */
24290 {
24296 /* A functional cast has a list of operands. */
24299 {
24300 /* If there are no operands, it must be an expression such
24301 as "int()". This should not happen for aggregate types
24302 because it would form non-constant expressions. */
24307 }
24313 }
24318 /* FALLTHRU */
24321 /* A `sizeof' expression is value-dependent if the operand is
24322 type-dependent or is a pack expansion. */
24331 /* An 'encode' expression is value-dependent if the operand is
24332 type-dependent. */
24341 /* All instantiation-dependent expressions should also be considered
24342 value-dependent. */
24350 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24351 is value-dependent. */
24352 {
24361 }
24364 {
24381 }
24392 {
24396 }
24399 /* Treat all requires-expressions as value-dependent so
24400 we don't try to fold them. */
24407 {
24414 {
24416 /* In a call to a constexpr member function, look through the
24417 implicit ADDR_EXPR on the object argument so that it doesn't
24418 cause the call to be considered value-dependent. We also
24419 look through it in potential_constant_expression. */
24426 }
24428 }
24434 {
24436 tree val;
24443 }
24446 /* Treat a GNU statement expression as dependent to avoid crashing
24447 under instantiate_non_dependent_expr; it can't be constant. */
24451 /* A constant expression is value-dependent if any subexpression is
24452 value-dependent. */
24454 {
24461 {
24465 {
24468 /* In some cases, some of the operands may be missing.
24469 (For example, in the case of PREDECREMENT_EXPR, the
24470 amount to increment by may be missing.) That doesn't
24471 make the expression dependent. */
24474 }
24475 }
24479 }
24481 }
24483 /* The expression is not value-dependent. */
24485 }
24487 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24488 [temp.dep.expr]. Note that an expression with no type is
24489 considered dependent. Other parts of the compiler arrange for an
24490 expression with type-dependent subexpressions to have no type, so
24491 this function doesn't have to be fully recursive. */
24493 bool
24495 {
24504 /* An unresolved name is always dependent. */
24510 /* A fold expression is type-dependent. */
24517 /* Some expression forms are never type-dependent. */
24531 /* The types of these expressions depends only on the type to which
24532 the cast occurs. */
24541 /* The types of these expressions depends only on the type created
24542 by the expression. */
24545 {
24546 /* For NEW_EXPR tree nodes created inside a template, either
24547 the object type itself or a TREE_LIST may appear as the
24548 operand 1. */
24551 /* This is an array type. We need to check array dimensions
24552 as well. */
24554 || value_dependent_expression_p
24556 else
24558 }
24561 {
24565 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24566 contains an identifier associated by name lookup with one or more
24567 declarations declared with a dependent type, or...a
24568 nested-name-specifier or qualified-id that names a member of an
24569 unknown specialization. */
24572 }
24582 {
24583 tree elt;
24587 {
24590 }
24592 }
24594 /* A static data member of the current instantiation with incomplete
24595 array type is type-dependent, as the definition and specializations
24596 can have different bounds. */
24603 /* An array of unknown bound depending on a variadic parameter, eg:
24605 template<typename... Args>
24606 void foo (Args... args)
24607 {
24608 int arr[] = { args... };
24609 }
24611 template<int... vals>
24612 void bar ()
24613 {
24614 int arr[] = { vals... };
24615 }
24617 If the array has no length and has an initializer, it must be that
24618 we couldn't determine its length in cp_complete_array_type because
24619 it is dependent. */
24627 /* A function or variable template-id is type-dependent if it has any
24628 dependent template arguments. */
24632 {
24633 /* Consider the innermost template arguments, since those are the ones
24634 that come from the template-id; the template arguments for the
24635 enclosing class do not make it type-dependent unless they are used in
24636 the type of the decl. */
24638 && (any_dependent_template_arguments_p
24641 }
24643 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24644 type-dependent. Checking this is important for functions with auto return
24645 type, which looks like a dependent type. */
24654 {
24658 }
24660 /* Always dependent, on the number of arguments if nothing else. */
24665 {
24670 {
24676 }
24677 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24682 {
24687 }
24690 {
24697 }
24707 }
24711 /* Dependent type attributes might not have made it from the decl to
24712 the type yet. */
24718 }
24720 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24721 type-dependent if the expression refers to a member of the current
24722 instantiation and the type of the referenced member is dependent, or the
24723 class member access expression refers to a member of an unknown
24724 specialization.
24726 This function returns true if the OBJECT in such a class member access
24727 expression is of an unknown specialization. */
24729 bool
24731 {
24732 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24733 dependent. */
24738 }
24740 /* walk_tree callback function for instantiation_dependent_expression_p,
24741 below. Returns non-zero if a dependent subexpression is found. */
24743 static tree
24746 {
24748 {
24749 /* We don't have to worry about decltype currently because decltype
24750 of an instantiation-dependent expr is a dependent type. This
24751 might change depending on the resolution of DR 1172. */
24754 }
24757 {
24758 /* Don't treat an argument list as dependent just because it has no
24759 TREE_TYPE. */
24767 /* Handle expressions with type operands. */
24772 {
24777 {
24780 else
24781 {
24784 }
24785 }
24787 }
24791 /* In a template, finish_class_member_access_expr creates a
24792 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24793 type-dependent, so that we can check access control at
24794 instantiation time (PR 42277). See also Core issue 1273. */
24801 else
24804 /* Treat statement-expressions as dependent. */
24808 /* Treat requires-expressions as dependent. */
24813 /* Treat calls to function concepts as dependent. */
24819 /* And variable concepts. */
24826 }
24830 else
24832 }
24834 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24835 sense defined by the ABI:
24837 "An expression is instantiation-dependent if it is type-dependent
24838 or value-dependent, or it has a subexpression that is type-dependent
24839 or value-dependent."
24841 Except don't actually check value-dependence for unevaluated expressions,
24842 because in sizeof(i) we don't care about the value of i. Checking
24843 type-dependence will in turn check value-dependence of array bounds/template
24844 arguments as needed. */
24846 bool
24848 {
24849 tree result;
24860 }
24862 /* As above, but also check value-dependence of the expression as a whole. */
24864 bool
24866 {
24869 }
24871 /* Like type_dependent_expression_p, but it also works while not processing
24872 a template definition, i.e. during substitution or mangling. */
24874 bool
24876 {
24882 }
24884 /* Returns TRUE if ARGS contains a type-dependent expression. */
24886 bool
24888 {
24890 tree arg;
24893 {
24896 }
24898 }
24900 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24901 expressions) contains any type-dependent expressions. */
24903 bool
24905 {
24911 }
24913 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24914 expressions) contains any value-dependent expressions. */
24916 bool
24918 {
24924 }
24926 /* Returns TRUE if the ARG (a template argument) is dependent. */
24928 bool
24930 {
24934 /* Assume a template argument that was wrongly written by the user
24935 is dependent. This is consistent with what
24936 any_dependent_template_arguments_p [that calls this function]
24937 does. */
24947 {
24950 /* A member template of a dependent class is not necessarily
24951 type-dependent, but it is a dependent template argument because it
24952 will be a member of an unknown specialization to that template. */
24955 }
24957 {
24961 {
24964 }
24967 }
24970 else
24973 }
24975 /* Returns true if ARGS (a collection of template arguments) contains
24976 any types that require structural equality testing. */
24978 bool
24980 {
24990 {
24993 {
24999 {
25000 /* Look inside the argument pack. */
25003 }
25006 {
25019 }
25020 }
25021 }
25024 }
25026 /* Returns true if ARGS (a collection of template arguments) contains
25027 any dependent arguments. */
25029 bool
25031 {
25041 {
25046 }
25049 }
25051 /* Returns TRUE if the template TMPL is type-dependent. */
25053 bool
25055 {
25057 {
25062 }
25064 /* Template template parameters are dependent. */
25068 /* So are names that have not been looked up. */
25072 }
25074 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25076 bool
25078 {
25081 }
25083 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25084 are dependent. */
25086 bool
25088 {
25095 {
25117 {
25121 }
25125 {
25129 {
25134 }
25135 }
25136 }
25139 }
25141 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25142 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25143 no such TYPE can be found. Note that this function peers inside
25144 uninstantiated templates and therefore should be used only in
25145 extremely limited situations. ONLY_CURRENT_P restricts this
25146 peering to the currently open classes hierarchy (which is required
25147 when comparing types). */
25149 tree
25151 {
25152 tree scope;
25153 tree name;
25154 tree decl;
25156 tree pushed_scope;
25157 tree result;
25162 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25163 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25164 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25165 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25166 identifier of the TYPENAME_TYPE anymore.
25167 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25168 TYPENAME_TYPE instead, we avoid messing up with a possible
25169 typedef variant case. */
25172 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25173 it first before we can figure out what NAME refers to. */
25175 {
25177 /* Given a class template A with a dependent base with nested type C,
25178 typedef typename A::C::C C will land us here, as trying to resolve
25179 the initial A::C leads to the local C typedef, which leads back to
25180 A::C::C. So we break the recursion now. */
25182 else
25184 }
25185 /* If we don't know what SCOPE refers to, then we cannot resolve the
25186 TYPENAME_TYPE. */
25189 /* If this is a typedef, we don't want to look inside (c++/11987). */
25192 /* If SCOPE isn't the template itself, it will not have a valid
25193 TYPE_FIELDS list. */
25195 /* scope is either the template itself or a compatible instantiation
25196 like X<T>, so look up the name in the original template. */
25198 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25200 /* If scope has no fields, it can't be a current instantiation. Check this
25201 before currently_open_class to avoid infinite recursion (71515). */
25204 /* If the SCOPE is not the current instantiation, there's no reason
25205 to look inside it. */
25208 /* Enter the SCOPE so that name lookup will be resolved as if we
25209 were in the class definition. In particular, SCOPE will no
25210 longer be considered a dependent type. */
25212 /* Look up the declaration. */
25214 tf_warning_or_error);
25218 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25219 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25225 {
25229 }
25232 {
25233 /* Obtain the template and the arguments. */
25236 {
25237 /* We get here with a plain identifier because a previous tentative
25238 parse of the nested-name-specifier as part of a ptr-operator saw
25239 ::template X<A>. The use of ::template is necessary in a
25240 ptr-operator, but wrong in a declarator-id.
25242 [temp.names]: In a qualified-id of a declarator-id, the keyword
25243 template shall not appear at the top level. */
25247 }
25249 /* Instantiate the template. */
25255 }
25257 /* Leave the SCOPE. */
25261 /* If we failed to resolve it, return the original typename. */
25265 /* If lookup found a typename type, resolve that too. */
25267 {
25268 /* Ill-formed programs can cause infinite recursion here, so we
25269 must catch that. */
25273 }
25275 /* Qualify the resulting type. */
25281 }
25283 /* EXPR is an expression which is not type-dependent. Return a proxy
25284 for EXPR that can be used to compute the types of larger
25285 expressions containing EXPR. */
25287 tree
25289 {
25291 tree inner_expr;
25293 /* When checking, try to get a constant value for all non-dependent
25294 expressions in order to expose bugs in *_dependent_expression_p
25295 and constexpr. This can affect code generation, see PR70704, so
25296 only do this for -fchecking=2. */
25299 /* Don't do this during nsdmi parsing as it can lead to
25300 unexpected recursive instantiations. */
25302 /* Don't do this during concept expansion either and for
25303 the same reason. */
25309 /* Preserve OVERLOADs; the functions must be available to resolve
25310 types. */
25321 /* There is no need to return a proxy for a variable. */
25324 /* Preserve string constants; conversions from string constants to
25325 "char *" are allowed, even though normally a "const char *"
25326 cannot be used to initialize a "char *". */
25329 /* Preserve void and arithmetic constants, as an optimization -- there is no
25330 reason to create a new node. */
25335 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25336 There is at least one place where we want to know that a
25337 particular expression is a throw-expression: when checking a ?:
25338 expression, there are special rules if the second or third
25339 argument is a throw-expression. */
25343 /* Don't wrap an initializer list, we need to be able to look inside. */
25347 /* Don't wrap a dummy object, we need to be able to test for it. */
25366 /* If the type is unknown, it can't really be non-dependent */
25369 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25371 }
25373 /* ARGS is a vector of expressions as arguments to a function call.
25374 Replace the arguments with equivalent non-dependent expressions.
25375 This modifies ARGS in place. */
25377 void
25379 {
25381 tree arg;
25384 {
25388 }
25389 }
25391 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25392 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25393 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25395 static tree
25397 {
25411 }
25413 tree
25415 {
25417 }
25419 tree
25421 {
25423 }
25425 /* Return a C++17 deduction placeholder for class template TMPL. */
25427 tree
25429 {
25433 }
25435 /* True iff T is a C++17 class template deduction placeholder. */
25437 bool
25439 {
25441 }
25443 /* Make a "constrained auto" type-specifier. This is an
25444 auto type with constraints that must be associated after
25445 deduction. The constraint is formed from the given
25446 CONC and its optional sequence of arguments, which are
25447 non-null if written as partial-concept-id. */
25449 tree
25451 {
25454 /* Build the constraint. */
25462 /* Our canonical type depends on the constraint. */
25465 /* Attach the constraint to the type declaration. */
25468 }
25470 /* Given type ARG, return std::initializer_list<ARG>. */
25472 static tree
25474 {
25478 {
25482 "deducing from brace-enclosed initializer list"
25486 }
25492 }
25494 /* Replace auto in TYPE with std::initializer_list<auto>. */
25496 static tree
25498 {
25505 }
25507 /* Hash traits for hashing possibly constrained 'auto'
25508 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25511 {
25514 };
25516 /* Hash the 'auto' T. */
25518 inline hashval_t
25520 {
25522 /* Matching constrained-type-specifiers denote the same template
25523 parameter, so hash the constraint. */
25525 else
25526 /* But unconstrained autos are all separate, so just hash the pointer. */
25528 }
25530 /* Compare two 'auto's. */
25534 {
25541 /* Two unconstrained autos are distinct. */
25546 }
25548 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25549 constrained) auto, add it to the vector. */
25551 static int
25553 {
25556 {
25557 /* All the autos were built with index 0; fix that up now. */
25561 /* If this is a repeated constrained-type-specifier, use the index we
25562 chose before. */
25564 else
25565 {
25566 /* Otherwise this is new, so use the current count. */
25569 }
25571 }
25573 /* Always keep walking. */
25575 }
25577 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25578 says they can appear anywhere in the type. */
25580 static tree
25582 {
25591 {
25596 }
25599 }
25601 /* The stem for deduction guide names. */
25604 /* Return the name for a deduction guide for class template TMPL. */
25606 tree
25608 {
25619 }
25621 /* True if NAME is the name of a deduction guide. */
25623 bool
25625 {
25630 }
25632 /* True if FN is a deduction guide. */
25634 bool
25636 {
25641 }
25643 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25645 bool
25647 {
25654 }
25656 /* True if FN is a guide generated from a constructor template. */
25658 bool
25660 {
25668 }
25670 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25671 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25672 template parameter types. Note that the handling of template template
25673 parameters relies on current_template_parms being set appropriately for the
25674 new template. */
25676 static tree
25679 {
25682 tree newtype;
25685 {
25692 }
25693 else
25697 tree newdecl
25702 tree newidx;
25705 {
25715 {
25720 // First create a copy (ttargs) of tsubst_args with an
25721 // additional level for the template template parameter's own
25722 // template parameters (ttparms).
25723 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25731 // Substitute ttargs into ttparms to fix references to
25732 // other template parameters.
25735 // Now substitute again with args based on tparms, to reduce
25736 // the level of the ttparms.
25739 complain);
25740 // Finally, tack the adjusted parms onto tparms.
25742 current_template_parms);
25744 }
25745 }
25746 else
25747 {
25749 tree newconst
25761 }
25764 }
25766 /* Returns a C++17 class deduction guide template based on the constructor
25767 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25768 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25770 static tree
25772 {
25776 location_t loc;
25780 {
25784 {
25787 }
25788 else
25798 }
25799 else
25800 {
25803 fn_tmpl
25813 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25814 fully specialized args for the enclosing class. Strip those off, as
25815 the deduction guide won't have those template parameters. */
25818 /* Discard the 'this' parameter. */
25826 {
25829 /* For a member template constructor, we need to flatten the two
25830 template parameter lists into one, and then adjust the function
25831 signature accordingly. This gets...complicated. */
25834 /* For a member template we should have two levels of parms/args, one
25835 for the class and one for the constructor. We stripped
25836 specialized args for further enclosing classes above. */
25840 /* Template args for translating references to the two-level template
25841 parameters into references to the one-level template parameters we
25842 are creating. */
25847 /* Template parms for the constructor template. */
25850 /* Template parms for the class template. */
25854 /* Template parms for the deduction guide start as a copy of the
25855 template parms for the class. We set current_template_parms for
25856 lookup_template_class_1. */
25862 /* Now we need to rewrite the constructor parms to append them to the
25863 class parms. */
25865 {
25880 }
25882 /* Now we have a final set of template parms to substitute into the
25883 function signature. */
25892 }
25894 }
25897 {
25898 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25902 }
25906 FUNCTION_DECL,
25923 }
25925 /* Deduce template arguments for the class template placeholder PTYPE for
25926 template TMPL based on the initializer INIT, and return the resulting
25927 type. */
25929 static tree
25931 tsubst_flags_t complain)
25932 {
25934 {
25935 /* We should have handled this in the caller. */
25941 }
25952 {
25955 {
25956 /* As an exception, the first phase in 16.3.1.7 (considering the
25957 initializer list as a single argument) is omitted if the
25958 initializer list consists of a single expression of type cv U,
25959 where U is a specialization of C or a class derived from a
25960 specialization of C. */
25971 }
25974 else
25976 }
25977 else
25988 /* Prune explicit deduction guides in copy-initialization context. */
25990 {
25996 {
25997 /* Found a nonconverting guide, prune the candidates. */
26004 }
26005 }
26010 {
26013 }
26016 // FIXME cache artificial deduction guides
26018 {
26023 else
26027 }
26031 /* If this is list-initialization and the class has a list constructor, first
26032 try deducing from the list as a single argument, as [over.match.list]. */
26036 {
26040 }
26042 {
26048 {
26049 /* That didn't work, now try treating the list as a sequence of
26050 arguments. */
26053 }
26054 }
26056 /* Maybe generate an implicit deduction guide. */
26058 {
26062 /* Generate a copy guide. */
26065 /* Generate a default guide. */
26069 {
26072 }
26073 }
26076 {
26078 " of %qT, as it has no non-explicit deduction guides or "
26081 }
26083 {
26087 }
26090 {
26094 }
26097 {
26107 }
26112 }
26114 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26115 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26116 The CONTEXT determines the context in which auto deduction is performed
26117 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26118 OUTER_TARGS are used during template argument deduction
26119 (context == adc_unify) to properly substitute the result, and is ignored
26120 in other contexts.
26122 For partial-concept-ids, extra args may be appended to the list of deduced
26123 template arguments prior to determining constraint satisfaction. */
26125 tree
26129 {
26130 tree targs;
26137 /* Defining a subset of type-dependent expressions that we can deduce
26138 from ahead of time isn't worth the trouble. */
26141 /* Similarly, we can't deduce from another undeduced decl. */
26146 /* C++17 class template argument deduction. */
26150 /* Nothing we can do with this, even in deduction context. */
26153 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26154 with either a new invented type template parameter U or, if the
26155 initializer is a braced-init-list (8.5.4), with
26156 std::initializer_list<U>. */
26158 {
26163 else
26164 {
26166 {
26170 "for deduction to %<std::initializer_list%>, use copy-"
26172 }
26174 }
26175 }
26186 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26187 and initializer has array type, deduce cv-qualified array type. */
26189 complain);
26191 {
26200 {
26204 }
26205 }
26206 else
26207 {
26209 tree tparms;
26213 else
26214 {
26218 }
26225 {
26227 /* Try again at instantiation time. */
26231 /* If type is error_mark_node a diagnostic must have been
26232 emitted by now. Also, having a mention to '<type error>'
26233 in the diagnostic is not really useful to the user. */
26234 {
26238 else
26243 }
26245 }
26246 }
26248 /* Check any placeholder constraints against the deduced type. */
26251 {
26252 /* Use the deduced type to check the associated constraints. If we
26253 have a partial-concept-id, rebuild the argument list so that
26254 we check using the extra arguments. */
26258 {
26261 }
26262 else
26265 {
26267 {
26269 {
26287 }
26289 }
26291 }
26292 }
26298 }
26300 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26301 result. */
26303 tree
26305 {
26307 {
26313 /* In an abbreviated function template we didn't know we were dealing
26314 with a function template when we saw the auto return type, so update
26315 it to have the correct level. */
26317 }
26319 }
26321 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26322 'decltype(auto)' or a deduced class template. */
26324 bool
26326 {
26332 else
26334 }
26336 /* for_each_template_parm callback for type_uses_auto. */
26338 int
26340 {
26342 }
26344 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26345 a use of `auto'. Returns NULL_TREE otherwise. */
26347 tree
26349 {
26353 {
26354 /* The Concepts TS allows multiple autos in one type-specifier; just
26355 return the first one we find, do_auto_deduction will collect all of
26356 them. */
26360 else
26362 }
26363 else
26365 }
26367 /* For a given template T, return the vector of typedefs referenced
26368 in T for which access check is needed at T instantiation time.
26369 T is either a FUNCTION_DECL or a RECORD_TYPE.
26370 Those typedefs were added to T by the function
26371 append_type_to_template_for_access_check. */
26375 {
26376 tree ti;
26387 {
26392 }
26395 }
26397 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26398 tied to T. That list of typedefs will be access checked at
26399 T instantiation time.
26400 T is either a FUNCTION_DECL or a RECORD_TYPE.
26401 TYPE_DECL is a TYPE_DECL node representing a typedef.
26402 SCOPE is the scope through which TYPE_DECL is accessed.
26403 LOCATION is the location of the usage point of TYPE_DECL.
26405 This function is a subroutine of
26406 append_type_to_template_for_access_check. */
26408 static void
26410 tree type_decl,
26411 tree scope,
26412 location_t location)
26413 {
26414 qualified_typedef_usage_t typedef_usage;
26415 tree ti;
26422 && type_decl
26436 }
26438 /* Append TYPE_DECL to the template TEMPL.
26439 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26440 At TEMPL instanciation time, TYPE_DECL will be checked to see
26441 if it can be accessed through SCOPE.
26442 LOCATION is the location of the usage point of TYPE_DECL.
26444 e.g. consider the following code snippet:
26446 class C
26447 {
26448 typedef int myint;
26449 };
26451 template<class U> struct S
26452 {
26453 C::myint mi; // <-- usage point of the typedef C::myint
26454 };
26456 S<char> s;
26458 At S<char> instantiation time, we need to check the access of C::myint
26459 In other words, we need to check the access of the myint typedef through
26460 the C scope. For that purpose, this function will add the myint typedef
26461 and the scope C through which its being accessed to a list of typedefs
26462 tied to the template S. That list will be walked at template instantiation
26463 time and access check performed on each typedefs it contains.
26464 Note that this particular code snippet should yield an error because
26465 myint is private to C. */
26467 void
26469 tree type_decl,
26470 tree scope,
26471 location_t location)
26472 {
26478 /* Make sure we don't append the type to the template twice. */
26485 }
26487 /* Convert the generic type parameters in PARM that match the types given in the
26488 range [START_IDX, END_IDX) from the current_template_parms into generic type
26489 packs. */
26491 tree
26493 {
26504 {
26505 /* Create a distinct parameter pack type from the current parm and add it
26506 to the replacement args to tsubst below into the generic function
26507 parameter. */
26522 }
26528 /* If there are more levels then build up the replacement with the outer
26529 template parms. */
26533 replacement);
26536 }
26538 /* Entries in the decl_constraint hash table. */
26540 {
26541 tree decl;
26542 tree ci;
26543 };
26545 /* Hashing function and equality for constraint entries. */
26547 {
26549 {
26551 }
26554 {
26556 }
26557 };
26559 /* A mapping from declarations to constraint information. Note that
26560 both templates and their underlying declarations are mapped to the
26561 same constraint information.
26563 FIXME: This is defined in pt.c because garbage collection
26564 code is not being generated for constraint.cc. */
26568 /* Returns the template constraints of declaration T. If T is not
26569 constrained, return NULL_TREE. Note that T must be non-null. */
26571 tree
26573 {
26584 else
26586 }
26588 /* Associate the given constraint information CI with the declaration
26589 T. If T is a template, then the constraints are associated with
26590 its underlying declaration. Don't build associations if CI is
26591 NULL_TREE. */
26593 void
26595 {
26607 }
26609 /* Remove the associated constraints of the declaration T. */
26611 void
26613 {
26622 }
26624 /* Memoized satisfaction results for declarations. This
26625 maps the pair (constraint_info, arguments) to the result computed
26626 by constraints_satisfied_p. */
26629 {
26630 tree ci;
26631 tree args;
26632 tree result;
26633 };
26635 /* Hashing function and equality for constraint entries. */
26638 {
26640 {
26643 }
26646 {
26648 }
26649 };
26651 /* Memoized satisfaction results for concept checks. */
26654 {
26655 tree tmpl;
26656 tree args;
26657 tree result;
26658 };
26660 /* Hashing function and equality for constraint entries. */
26663 {
26665 {
26667 }
26670 {
26675 }
26676 };
26681 /* Search for a memoized satisfaction result. Returns one of the
26682 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26684 tree
26686 {
26691 else
26693 }
26695 /* Memoize the result of a satisfication test. Returns the saved result. */
26697 tree
26699 {
26706 }
26708 /* Search for a memoized satisfaction result for a concept. */
26710 tree
26712 {
26717 else
26719 }
26721 /* Memoize the result of a concept check. Returns the saved result. */
26723 tree
26725 {
26732 }
26736 /* Returns a prior concept specialization. This returns the substituted
26737 and normalized constraints defined by the concept. */
26739 tree
26741 {
26746 else
26748 }
26750 /* Save a concept expansion for later. */
26752 tree
26754 {
26761 }
26763 static hashval_t
26765 {
26774 }
26776 /* Compare the constraints of two subsumption entries. The LEFT1 and
26777 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26778 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26780 static bool
26782 {
26790 }
26792 /* Key/value pair for learning and memoizing subsumption results. This
26793 associates a pair of check constraints (including arguments) with
26794 a boolean value indicating the result. */
26797 {
26798 tree t1;
26799 tree t2;
26801 };
26803 /* Hashing function and equality for constraint entries. */
26806 {
26808 {
26810 }
26813 {
26818 }
26819 };
26823 /* Search for a previously cached subsumption result. */
26827 {
26832 else
26834 }
26836 /* Save a subsumption result. */
26838 bool
26840 {
26847 }
26849 /* Set up the hash table for constraint association. */
26851 void
26853 {
26862 }
26864 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26865 0..N-1. */
26867 void
26869 {
26872 integer_type_node,
26873 NULL_TREE),
26877 }
26879 /* Set up the hash tables for template instantiations. */
26881 void
26883 {
26889 }
26891 /* Print stats about the template hash tables for -fstats. */
26893 void
26895 {
26904 }
26906 #if CHECKING_P
26910 /* Verify that build_non_dependent_expr () works, for various expressions,
26911 and that location wrappers don't affect the results. */
26913 static void
26915 {
26918 /* Verify constants, without and with location wrappers. */
26935 }
26937 /* Verify that type_dependent_expression_p () works correctly, even
26938 in the presence of location wrapper nodes. */
26940 static void
26942 {
26947 /* If no templates are involved, nothing is type-dependent. */
26953 /* Within a template, an unresolved name is always type-dependent. */
26956 /* Ensure it copes with NULL_TREE and errors. */
26960 /* A USING_DECL in a template should be type-dependent, even if wrapped
26961 with a location wrapper (PR c++/83799). */
26970 }
26972 /* Run all of the selftests within this file. */
26974 void
26976 {
26979 }