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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2017 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". */
44 /* The type of functions taking a tree, and some additional data, and
45 returning an int. */
48 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
49 instantiations have been deferred, either because their definitions
50 were not yet available, or because we were putting off doing the work. */
54 };
69 /* Live only within one (recursive) call to tsubst_expr. We use
70 this to pass the statement expression node from the STMT_EXPR
71 to the EXPR_STMT that is its result. */
74 // -------------------------------------------------------------------------- //
75 // Local Specialization Stack
76 //
77 // Implementation of the RAII helper for creating new local
78 // specializations.
81 {
83 }
86 {
89 }
91 /* True if we've recursed into fn_type_unification too many times. */
95 {
96 tree tmpl;
97 tree args;
98 tree spec;
99 };
102 {
105 };
111 /* Contains canonical template parameter types. The vector is indexed by
112 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
113 TREE_LIST, whose TREE_VALUEs contain the canonical template
114 parameters of various types and levels. */
117 #define UNIFY_ALLOW_NONE 0
118 #define UNIFY_ALLOW_MORE_CV_QUAL 1
119 #define UNIFY_ALLOW_LESS_CV_QUAL 2
120 #define UNIFY_ALLOW_DERIVED 4
121 #define UNIFY_ALLOW_INTEGER 8
122 #define UNIFY_ALLOW_OUTER_LEVEL 16
123 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
124 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
127 tbr_incomplete_type,
128 tbr_ambiguous_baseclass,
129 tbr_success
130 };
153 tree);
210 location_t);
219 /* Make the current scope suitable for access checking when we are
220 processing T. T can be FUNCTION_DECL for instantiated function
221 template, VAR_DECL for static member variable, or TYPE_DECL for
222 alias template (needed by instantiate_decl). */
224 static void
226 {
234 else
238 {
239 saved_access_scope = tree_cons
242 }
243 }
245 /* Restore the scope set up by push_access_scope. T is the node we
246 are processing. */
248 static void
250 {
252 {
255 }
259 else
261 }
263 /* Do any processing required when DECL (a member template
264 declaration) is finished. Returns the TEMPLATE_DECL corresponding
265 to DECL, unless it is a specialization, in which case the DECL
266 itself is returned. */
268 tree
270 {
277 {
278 tree type;
286 {
290 }
292 }
296 {
298 {
301 }
302 else
304 }
305 else
309 }
311 /* Create a template info node. */
313 tree
315 {
320 }
322 /* Return the template info node corresponding to T, whatever T is. */
324 tree
326 {
348 }
350 /* Returns the template nesting level of the indicated class TYPE.
352 For example, in:
353 template <class T>
354 struct A
355 {
356 template <class U>
357 struct B {};
358 };
360 A<T>::B<U> has depth two, while A<T> has depth one.
361 Both A<T>::B<int> and A<int>::B<U> have depth one, if
362 they are instantiations, not specializations.
364 This function is guaranteed to return 0 if passed NULL_TREE so
365 that, for example, `template_class_depth (current_class_type)' is
366 always safe. */
368 int
370 {
374 {
385 else
387 }
390 }
392 /* Subroutine of maybe_begin_member_template_processing.
393 Returns true if processing DECL needs us to push template parms. */
395 static bool
397 {
403 }
405 /* Subroutine of maybe_begin_member_template_processing.
406 Push the template parms in PARMS, starting from LEVELS steps into the
407 chain, and ending at the beginning, since template parms are listed
408 innermost first. */
410 static void
412 {
420 current_template_parms
426 NULL);
428 {
437 {
444 /* Push the CONST_DECL. */
450 }
451 }
452 }
454 /* Restore the template parameter context for a member template, a
455 friend template defined in a class definition, or a non-template
456 member of template class. */
458 void
460 {
461 tree parms;
466 {
469 /* Disregard full specializations (c++/60999). */
472 }
475 {
480 {
483 }
486 }
488 /* Remember how many levels of template parameters we pushed so that
489 we can pop them later. */
491 }
493 /* Undo the effects of maybe_begin_member_template_processing. */
495 void
497 {
506 {
510 }
511 }
513 /* Return a new template argument vector which contains all of ARGS,
514 but has as its innermost set of arguments the EXTRA_ARGS. */
516 static tree
518 {
519 tree new_args;
537 }
539 /* Like add_to_template_args, but only the outermost ARGS are added to
540 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
541 (EXTRA_ARGS) levels are added. This function is used to combine
542 the template arguments from a partial instantiation with the
543 template arguments used to attain the full instantiation from the
544 partial instantiation. */
546 static tree
548 {
549 tree new_args;
551 /* If there are more levels of EXTRA_ARGS than there are ARGS,
552 something very fishy is going on. */
555 /* If *all* the new arguments will be the EXTRA_ARGS, just return
556 them. */
560 /* For the moment, we make ARGS look like it contains fewer levels. */
565 /* Now, we restore ARGS to its full dimensions. */
569 }
571 /* Return the N levels of innermost template arguments from the ARGS. */
573 tree
575 {
576 tree new_args;
582 /* If N is 1, just return the innermost set of template arguments. */
586 /* If we're not removing anything, just return the arguments we were
587 given. */
593 /* Make a new set of arguments, not containing the outer arguments. */
600 }
602 /* The inverse of get_innermost_template_args: Return all but the innermost
603 EXTRA_LEVELS levels of template arguments from the ARGS. */
605 static tree
607 {
608 tree new_args;
614 /* If N is 1, just return the outermost set of template arguments. */
618 /* If we're not removing anything, just return the arguments we were
619 given. */
624 /* Make a new set of arguments, not containing the inner arguments. */
631 }
633 /* We've got a template header coming up; push to a new level for storing
634 the parms. */
636 void
638 {
639 /* We use a non-tag-transparent scope here, which causes pushtag to
640 put tags in this scope, rather than in the enclosing class or
641 namespace scope. This is the right thing, since we want
642 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
643 global template class, push_template_decl handles putting the
644 TEMPLATE_DECL into top-level scope. For a nested template class,
645 e.g.:
647 template <class T> struct S1 {
648 template <class T> struct S2 {};
649 };
651 pushtag contains special code to call pushdecl_with_scope on the
652 TEMPLATE_DECL for S2. */
658 /* Add a dummy parameter level while we process the parameter list. */
659 current_template_parms
662 current_template_parms);
663 }
665 /* This routine is called when a specialization is declared. If it is
666 invalid to declare a specialization here, an error is reported and
667 false is returned, otherwise this routine will return true. */
669 static bool
671 {
674 /* [temp.expl.spec]
676 An explicit specialization shall be declared in the namespace of
677 which the template is a member, or, for member templates, in the
678 namespace of which the enclosing class or enclosing class
679 template is a member. An explicit specialization of a member
680 function, member class or static data member of a class template
681 shall be declared in the namespace of which the class template
682 is a member. */
684 {
687 }
689 /* [temp.expl.spec]
691 In an explicit specialization declaration for a member of a class
692 template or a member template that appears in namespace scope,
693 the member template and some of its enclosing class templates may
694 remain unspecialized, except that the declaration shall not
695 explicitly specialize a class member template if its enclosing
696 class templates are not explicitly specialized as well. */
698 {
701 }
704 }
706 /* We've just seen template <>. */
708 bool
710 {
714 }
716 /* Called at then end of processing a declaration preceded by
717 template<>. */
719 void
721 {
724 }
726 /* Any template <>'s that we have seen thus far are not referring to a
727 function specialization. */
729 void
731 {
734 }
736 /* We've just seen a template header. If SPECIALIZATION is nonzero,
737 it was of the form template <>. */
739 static void
741 {
743 template_header_count++;
744 }
746 /* We're beginning an explicit instantiation. */
748 void
750 {
753 }
756 void
758 {
761 }
763 /* An explicit specialization or partial specialization of TMPL is being
764 declared. Check that the namespace in which the specialization is
765 occurring is permissible. Returns false iff it is invalid to
766 specialize TMPL in the current namespace. */
768 static bool
770 {
773 /* [tmpl.expl.spec]
775 An explicit specialization shall be declared in a namespace enclosing the
776 specialized template. An explicit specialization whose declarator-id is
777 not qualified shall be declared in the nearest enclosing namespace of the
778 template, or, if the namespace is inline (7.3.1), any namespace from its
779 enclosing namespace set. */
782 {
785 }
790 /* Same or enclosing namespace. */
792 else
793 {
799 }
800 }
802 /* SPEC is an explicit instantiation. Check that it is valid to
803 perform this explicit instantiation in the current namespace. */
805 static void
807 {
808 tree ns;
810 /* DR 275: An explicit instantiation shall appear in an enclosing
811 namespace of its template. */
817 }
819 // Returns the type of a template specialization only if that
820 // specialization needs to be defined. Otherwise (e.g., if the type has
821 // already been defined), the function returns NULL_TREE.
822 static tree
824 {
825 // An implicit instantiation of an incomplete type implies
826 // the definition of a new class template.
827 //
828 // template<typename T>
829 // struct S;
830 //
831 // template<typename T>
832 // struct S<T*>;
833 //
834 // Here, S<T*> is an implicit instantiation of S whose type
835 // is incomplete.
839 // It can also be the case that TYPE is a completed specialization.
840 // Continuing the previous example, suppose we also declare:
841 //
842 // template<typename T>
843 // requires Integral<T>
844 // struct S<T*>;
845 //
846 // Here, S<T*> refers to the specialization S<T*> defined
847 // above. However, we need to differentiate definitions because
848 // we intend to define a new partial specialization. In this case,
849 // we rely on the fact that the constraints are different for
850 // this declaration than that above.
851 //
852 // Note that we also get here for injected class names and
853 // late-parsed template definitions. We must ensure that we
854 // do not create new type declarations for those cases.
856 {
860 // If there are no template parameters, this cannot be a new
861 // partial template specializtion?
865 // The injected-class-name is not a new partial specialization.
869 // If the constraints are not the same as those of the primary
870 // then, we can probably create a new specialization.
874 {
878 }
880 // Also, if there's a pre-existing specialization with matching
881 // constraints, then this also isn't new.
884 {
892 }
894 // Create a new type node (and corresponding type decl)
895 // for the newly declared specialization.
900 /* We only need a separate type node for storing the definition of this
901 partial specialization; uses of S<T*> are unconstrained, so all are
902 equivalent. So keep TYPE_CANONICAL the same. */
905 // Build the corresponding type decl.
911 }
914 }
916 /* The TYPE is being declared. If it is a template type, that means it
917 is a partial specialization. Do appropriate error-checking. */
919 tree
921 {
922 tree context;
927 /* A lambda that appears in specialization context is not itself a
928 specialization. */
933 {
937 }
942 {
948 else
951 }
953 {
954 /* This is for ordinary explicit specialization and partial
955 specialization of a template class such as:
957 template <> class C<int>;
959 or:
961 template <class T> class C<T*>;
963 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
966 {
973 {
978 }
979 }
985 /* Trying to define a specialization either without a template<> header
986 or in an inappropriate place. We've already given an error, so just
987 bail now so we don't actually define the specialization. */
989 }
995 {
996 /* This is for an explicit specialization of member class
997 template according to [temp.expl.spec/18]:
999 template <> template <class U> class C<int>::D;
1001 The context `C<int>' must be an implicit instantiation.
1002 Otherwise this is just a member class template declared
1003 earlier like:
1005 template <> class C<int> { template <class U> class D; };
1006 template <> template <class U> class C<int>::D;
1008 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1009 while in the second case, `C<int>::D' is a primary template
1010 and `C<T>::D' may not exist. */
1014 {
1015 tree t;
1020 {
1025 }
1027 /* Check for invalid specialization after instantiation:
1029 template <> template <> class C<int>::D<int>;
1030 template <> template <class U> class C<int>::D; */
1034 {
1038 {
1039 /* We already have a full specialization of this partial
1040 instantiation, or a full specialization has been
1041 looked up but not instantiated. Reassign it to the
1042 new member specialization template. */
1043 spec_entry elt;
1055 spec_entry **slot
1060 }
1061 else
1062 /* But if we've had an implicit instantiation, that's a
1063 problem ([temp.expl.spec]/6). */
1066 }
1068 /* Mark TYPE as a specialization. And as a result, we only
1069 have one level of template argument for the innermost
1070 class template. */
1075 }
1076 }
1078 {
1079 /* Someday C++0x may allow for enum template specialization. */
1084 else
1085 {
1088 }
1089 }
1092 }
1094 /* Returns nonzero if we can optimize the retrieval of specializations
1095 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1096 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1100 {
1103 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1104 parameter. */
1106 /* The optimized lookup depends on the fact that the
1107 template arguments for the member function template apply
1108 purely to the containing class, which is not true if the
1109 containing class is an explicit or partial
1110 specialization. */
1114 /* It is possible to have a template that is not a member
1115 template and is not a member of a template class:
1117 template <typename T>
1118 struct S { friend A::f(); };
1120 Here, the friend function is a template, but the context does
1121 not have template information. The optimized lookup relies
1122 on having ARGS be the template arguments for both the class
1123 and the function template. */
1125 }
1127 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1128 gone through coerce_template_parms by now. */
1130 static void
1132 {
1135 {
1138 {
1145 /* Allow typedefs on the type of a non-type argument, since a
1147 else
1149 }
1150 }
1152 }
1154 /* Retrieve the specialization (in the sense of [temp.spec] - a
1155 specialization is either an instantiation or an explicit
1156 specialization) of TMPL for the given template ARGS. If there is
1157 no such specialization, return NULL_TREE. The ARGS are a vector of
1158 arguments, or a vector of vectors of arguments, in the case of
1159 templates with more than one level of parameters.
1161 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1162 then we search for a partial specialization matching ARGS. This
1163 parameter is ignored if TMPL is not a class template.
1165 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1166 result is a NONTYPE_ARGUMENT_PACK. */
1168 static tree
1170 {
1180 /* There should be as many levels of arguments as there are
1181 levels of parameters. */
1191 {
1192 tree class_template;
1193 tree class_specialization;
1195 tree fns;
1198 /* The template arguments actually apply to the containing
1199 class. Find the class specialization with those
1200 arguments. */
1202 class_specialization
1206 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1207 for the specialization. */
1211 /* Iterate through the methods with the indicated name, looking
1212 for the one that has an instance of TMPL. */
1215 {
1218 /* using-declarations can add base methods to the method vec,
1219 and we don't want those here. */
1222 }
1224 }
1225 else
1226 {
1228 spec_entry elt;
1237 else
1245 }
1248 }
1250 /* Like retrieve_specialization, but for local declarations. */
1252 tree
1254 {
1260 }
1262 /* Returns nonzero iff DECL is a specialization of TMPL. */
1264 int
1266 {
1267 tree t;
1270 {
1276 }
1277 else
1278 {
1287 }
1290 }
1292 /* Returns nonzero iff DECL is a specialization of friend declaration
1293 FRIEND_DECL according to [temp.friend]. */
1295 bool
1297 {
1304 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1305 of a template class, we want to check if DECL is a specialization
1306 if this. */
1310 {
1311 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1314 }
1319 /* There is nothing to do if this is not a template friend. */
1326 /* [temp.friend/6]
1327 A member of a class template may be declared to be a friend of a
1328 non-template class. In this case, the corresponding member of
1329 every specialization of the class template is a friend of the
1330 class granting friendship.
1332 For example, given a template friend declaration
1334 template <class T> friend void A<T>::f();
1336 the member function below is considered a friend
1338 template <> struct A<int> {
1339 void f();
1340 };
1342 For this type of template friend, TEMPLATE_DEPTH below will be
1343 nonzero. To determine if DECL is a friend of FRIEND, we first
1344 check if the enclosing class is a specialization of another. */
1351 {
1352 /* Next, we check the members themselves. In order to handle
1353 a few tricky cases, such as when FRIEND_DECL's are
1355 template <class T> friend void A<T>::g(T t);
1356 template <class T> template <T t> friend void A<T>::h();
1358 and DECL's are
1360 void A<int>::g(int);
1361 template <int> void A<int>::h();
1363 we need to figure out ARGS, the template arguments from
1364 the context of DECL. This is required for template substitution
1365 of `T' in the function parameter of `g' and template parameter
1366 of `h' in the above examples. Here ARGS corresponds to `int'. */
1373 {
1375 {
1378 else
1380 current_depth++;
1381 }
1383 }
1386 {
1388 tree friend_type;
1389 tree decl_type;
1390 tree friend_args_type;
1391 tree decl_args_type;
1393 /* Make sure that both DECL and FRIEND_DECL are templates or
1394 non-templates. */
1400 {
1401 /* If both are templates, check template parameter list. */
1402 tree friend_parms
1407 friend_parms))
1411 }
1412 else
1420 /* Check if return types match. */
1424 /* Check if function parameter types match, ignoring the
1425 `this' parameter. */
1434 }
1435 else
1436 {
1437 /* DECL is a TYPE_DECL */
1441 /* Make sure that both DECL and FRIEND_DECL are templates or
1442 non-templates. */
1443 is_template
1450 {
1451 tree friend_parms;
1452 /* If both are templates, check the name of the two
1453 TEMPLATE_DECL's first because is_friend didn't. */
1458 /* Now check template parameter list. */
1459 friend_parms
1462 return comp_template_parms
1464 friend_parms);
1465 }
1466 else
1469 }
1470 }
1472 }
1474 /* Register the specialization SPEC as a specialization of TMPL with
1475 the indicated ARGS. IS_FRIEND indicates whether the specialization
1476 is actually just a friend declaration. Returns SPEC, or an
1477 equivalent prior declaration, if available.
1479 We also store instantiations of field packs in the hash table, even
1480 though they are not themselves templates, to make lookup easier. */
1482 static tree
1484 hashval_t hash)
1485 {
1486 tree fn;
1488 spec_entry elt;
1496 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1497 register it; we want the corresponding TEMPLATE_DECL instead.
1498 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1499 the more obvious `uses_template_parms (spec)' to avoid problems
1500 with default function arguments. In particular, given
1501 something like this:
1503 template <class T> void f(T t1, T t = T())
1505 the default argument expression is not substituted for in an
1506 instantiation unless and until it is actually needed. */
1510 /* We don't put these specializations in the hash table, but we might
1511 want to give an error about a mismatch. */
1513 else
1514 {
1522 slot =
1526 else
1528 }
1530 /* We can sometimes try to re-register a specialization that we've
1531 already got. In particular, regenerate_decl_from_template calls
1532 duplicate_decls which will update the specialization list. But,
1533 we'll still get called again here anyhow. It's more convenient
1534 to simply allow this than to try to prevent it. */
1538 {
1540 {
1543 {
1545 fn);
1547 }
1548 else
1549 {
1550 tree clone;
1551 /* This situation should occur only if the first
1552 specialization is an implicit instantiation, the
1553 second is an explicit specialization, and the
1554 implicit instantiation has not yet been used. That
1555 situation can occur if we have implicitly
1556 instantiated a member function and then specialized
1557 it later.
1559 We can also wind up here if a friend declaration that
1560 looked like an instantiation turns out to be a
1561 specialization:
1563 template <class T> void foo(T);
1564 class S { friend void foo<>(int) };
1565 template <> void foo(int);
1567 We transform the existing DECL in place so that any
1568 pointers to it become pointers to the updated
1569 declaration.
1571 If there was a definition for the template, but not
1572 for the specialization, we want this to look as if
1573 there were no definition, and vice versa. */
1576 /* The call to duplicate_decls will have applied
1577 [temp.expl.spec]:
1579 An explicit specialization of a function template
1580 is inline only if it is explicitly declared to be,
1581 and independently of whether its function template
1582 is.
1584 to the primary function; now copy the inline bits to
1585 the various clones. */
1587 {
1594 }
1598 }
1599 }
1601 {
1604 /* We've already complained in duplicate_decls. */
1608 /* Dup decl failed, but this is a new definition. Set the
1609 line number so any errors match this new
1610 definition. */
1614 }
1615 }
1619 /* A specialization must be declared in the same namespace as the
1620 template it is specializing. */
1626 {
1635 /* If TMPL is a forward declaration of a template function, keep a list
1636 of all specializations in case we need to reassign them to a friend
1637 template later in tsubst_friend_function.
1639 Also keep a list of all variable template instantiations so that
1640 process_partial_specialization can check whether a later partial
1641 specialization would have used it. */
1644 }
1647 }
1649 /* Returns true iff two spec_entry nodes are equivalent. */
1653 bool
1655 {
1662 /* tmpl could be a FIELD_DECL for a capture pack. */
1666 {
1667 /* Partial specializations of a variable template can be distinguished by
1668 constraints. */
1672 }
1676 }
1678 /* Returns a hash for a template TMPL and template arguments ARGS. */
1680 static hashval_t
1682 {
1685 }
1687 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1688 ignoring SPEC. */
1690 hashval_t
1692 {
1694 }
1696 /* Recursively calculate a hash value for a template argument ARG, for use
1697 in the hash tables of template specializations. */
1699 hashval_t
1701 {
1721 {
1729 {
1734 }
1756 {
1760 {
1763 }
1765 }
1769 {
1772 }
1783 val = iterative_hash_template_arg
1795 val);
1797 val);
1806 /* A lambda can't appear in a template arg, but don't crash on
1807 erroneous input. */
1819 /* Now hash operands as usual. */
1824 }
1827 {
1830 {
1831 // We want an alias specialization that survived strip_typedefs
1832 // to hash differently from its TYPE_CANONICAL, to avoid hash
1833 // collisions that compare as different in template_args_equal.
1834 // These could be dependent specializations that strip_typedefs
1835 // left alone, or untouched specializations because
1836 // coerce_template_parms returns the unconverted template
1837 // arguments if it sees incomplete argument packs.
1840 }
1843 val);
1846 /* Otherwise just compare the types during lookup. */
1855 {
1860 }
1861 }
1864 }
1866 /* Unregister the specialization SPEC as a specialization of TMPL.
1867 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1868 if the SPEC was listed as a specialization of TMPL.
1870 Note that SPEC has been ggc_freed, so we can't look inside it. */
1872 bool
1874 {
1876 spec_entry elt;
1884 {
1889 }
1892 }
1894 /* Like register_specialization, but for local declarations. We are
1895 registering SPEC, an instantiation of TMPL. */
1897 void
1899 {
1901 }
1903 /* TYPE is a class type. Returns true if TYPE is an explicitly
1904 specialized class. */
1906 bool
1908 {
1912 }
1914 /* Print the list of functions at FNS, going through all the overloads
1915 for each element of the list. Alternatively, FNS can not be a
1916 TREE_LIST, in which case it will be printed together with all the
1917 overloads.
1919 MORE and *STR should respectively be FALSE and NULL when the function
1920 is called from the outside. They are used internally on recursive
1921 calls. print_candidates manages the two parameters and leaves NULL
1922 in *STR when it ends. */
1924 static void
1926 {
1932 {
1936 }
1937 else
1938 {
1941 {
1942 /* Pick the prefix string. */
1944 {
1948 }
1952 }
1955 }
1958 {
1961 }
1962 }
1964 /* Print the list of candidate FNS in an error message. FNS can also
1965 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1967 void
1969 {
1973 }
1975 /* Get a (possibly) constrained template declaration for the
1976 purpose of ordering candidates. */
1977 static tree
1979 {
1985 }
1987 /* Among candidates having the same signature, return the
1988 most constrained or NULL_TREE if there is no best candidate.
1989 If the signatures of candidates vary (e.g., template
1990 specialization vs. member function), then there can be no
1991 most constrained.
1993 Note that we don't compare constraints on the functions
1994 themselves, but rather those of their templates. */
1995 static tree
1997 {
1998 // Try to find the best candidate in a first pass.
2001 {
2008 }
2010 // Verify that the champ is better than previous candidates.
2015 }
2018 }
2021 /* Returns the template (one of the functions given by TEMPLATE_ID)
2022 which can be specialized to match the indicated DECL with the
2023 explicit template args given in TEMPLATE_ID. The DECL may be
2024 NULL_TREE if none is available. In that case, the functions in
2025 TEMPLATE_ID are non-members.
2027 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2028 specialization of a member template.
2030 The TEMPLATE_COUNT is the number of references to qualifying
2031 template classes that appeared in the name of the function. See
2032 check_explicit_specialization for a more accurate description.
2034 TSK indicates what kind of template declaration (if any) is being
2035 declared. TSK_TEMPLATE indicates that the declaration given by
2036 DECL, though a FUNCTION_DECL, has template parameters, and is
2037 therefore a template function.
2039 The template args (those explicitly specified and those deduced)
2040 are output in a newly created vector *TARGS_OUT.
2042 If it is impossible to determine the result, an error message is
2043 issued. The error_mark_node is returned to indicate failure. */
2045 static tree
2047 tree decl,
2051 tmpl_spec_kind tsk)
2052 {
2053 tree fns;
2054 tree targs;
2055 tree explicit_targs;
2058 /* A TREE_LIST of templates of which DECL may be a specialization.
2059 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2060 corresponding TREE_PURPOSE is the set of template arguments that,
2061 when used to instantiate the template, would produce a function
2062 with the signature of DECL. */
2072 /* We shouldn't be specializing a member template of an
2073 unspecialized class template; we already gave an error in
2074 check_specialization_scope, now avoid crashing. */
2077 {
2080 }
2088 /* Check for baselinks. */
2093 {
2096 }
2098 {
2101 }
2103 /* Count the number of template headers specified for this
2104 specialization. */
2114 {
2117 tf_warning_or_error,
2121 }
2123 {
2127 {
2128 tree decl_arg_types;
2129 tree fn_arg_types;
2130 tree insttype;
2132 /* In case of explicit specialization, we need to check if
2133 the number of template headers appearing in the specialization
2134 is correct. This is usually done in check_explicit_specialization,
2135 but the check done there cannot be exhaustive when specializing
2136 member functions. Consider the following code:
2138 template <> void A<int>::f(int);
2139 template <> template <> void A<int>::f(int);
2141 Assuming that A<int> is not itself an explicit specialization
2142 already, the first line specializes "f" which is a non-template
2143 member function, whilst the second line specializes "f" which
2144 is a template member function. So both lines are syntactically
2145 correct, and check_explicit_specialization does not reject
2146 them.
2148 Here, we can do better, as we are matching the specialization
2149 against the declarations. We count the number of template
2150 headers, and we check if they match TEMPLATE_COUNT + 1
2151 (TEMPLATE_COUNT is the number of qualifying template classes,
2152 plus there must be another header for the member template
2153 itself).
2155 Notice that if header_count is zero, this is not a
2156 specialization but rather a template instantiation, so there
2157 is no check we can perform here. */
2161 /* Check that the number of template arguments at the
2162 innermost level for DECL is the same as for FN. */
2170 /* DECL might be a specialization of FN. */
2174 /* For a non-static member function, we need to make sure
2175 that the const qualification is the same. Since
2176 get_bindings does not try to merge the "this" parameter,
2177 we must do the comparison explicitly. */
2183 /* Skip the "this" parameter and, for constructors of
2184 classes with virtual bases, the VTT parameter. A
2185 full specialization of a constructor will have a VTT
2186 parameter, but a template never will. */
2187 decl_arg_types
2189 fn_arg_types
2192 /* Function templates cannot be specializations; there are
2193 no partial specializations of functions. Therefore, if
2194 the type of DECL does not match FN, there is no
2195 match.
2197 Note that it should never be the case that we have both
2198 candidates added here, and for regular member functions
2199 below. */
2201 {
2205 }
2207 /* See whether this function might be a specialization of this
2208 template. Suppress access control because we might be trying
2209 to make this specialization a friend, and we have already done
2210 access control for the declaration of the specialization. */
2216 /* We cannot deduce template arguments that when used to
2217 specialize TMPL will produce DECL. */
2220 /* Remove, from the set of candidates, all those functions
2221 whose constraints are not satisfied. */
2225 // Then, try to form the new function type.
2229 fn_arg_types
2234 /* Save this template, and the arguments deduced. */
2236 }
2238 /* FN is an ordinary member function, and we need a
2239 specialization of a member template. */
2240 ;
2242 /* We can get IDENTIFIER_NODEs here in certain erroneous
2243 cases. */
2244 ;
2246 /* This is just an ordinary non-member function. Nothing can
2247 be a specialization of that. */
2248 ;
2250 /* Cannot specialize functions that are created implicitly. */
2251 ;
2252 else
2253 {
2254 tree decl_arg_types;
2256 /* This is an ordinary member function. However, since
2257 we're here, we can assume its enclosing class is a
2258 template class. For example,
2260 template <typename T> struct S { void f(); };
2261 template <> void S<int>::f() {}
2263 Here, S<int>::f is a non-template, but S<int> is a
2264 template class. If FN has the same type as DECL, we
2265 might be in business. */
2268 /* Its enclosing class is an explicit specialization
2269 of a template class. This is not a candidate. */
2274 /* The return types differ. */
2277 /* Adjust the type of DECL in case FN is a static member. */
2284 decl_arg_types))
2287 // If the deduced arguments do not satisfy the constraints,
2288 // this is not a candidate.
2292 // Add the candidate.
2294 }
2295 }
2298 {
2299 /* We have:
2301 [temp.expl.spec]
2303 It is possible for a specialization with a given function
2304 signature to be instantiated from more than one function
2305 template. In such cases, explicit specification of the
2306 template arguments must be used to uniquely identify the
2307 function template specialization being specialized.
2309 Note that here, there's no suggestion that we're supposed to
2310 determine which of the candidate templates is most
2311 specialized. However, we, also have:
2313 [temp.func.order]
2315 Partial ordering of overloaded function template
2316 declarations is used in the following contexts to select
2317 the function template to which a function template
2318 specialization refers:
2320 -- when an explicit specialization refers to a function
2321 template.
2323 So, we do use the partial ordering rules, at least for now.
2324 This extension can only serve to make invalid programs valid,
2325 so it's safe. And, there is strong anecdotal evidence that
2326 the committee intended the partial ordering rules to apply;
2327 the EDG front end has that behavior, and John Spicer claims
2328 that the committee simply forgot to delete the wording in
2329 [temp.expl.spec]. */
2332 {
2335 }
2336 }
2338 // Concepts allows multiple declarations of member functions
2339 // with the same signature. Like above, we need to rely on
2340 // on the partial ordering of those candidates to determine which
2341 // is the best.
2343 {
2345 {
2348 }
2349 }
2352 {
2359 else
2362 }
2366 {
2372 }
2374 /* We have one, and exactly one, match. */
2376 {
2380 // Propagate the candidate's constraints to the declaration.
2383 /* DECL is a re-declaration or partial instantiation of a template
2384 function. */
2387 /* It was a specialization of an ordinary member function in a
2388 template class. */
2390 }
2392 /* It was a specialization of a template. */
2395 {
2400 }
2401 else
2404 }
2406 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2407 but with the default argument values filled in from those in the
2408 TMPL_TYPES. */
2410 static tree
2412 tree tmpl_types)
2413 {
2414 tree new_spec_types;
2422 /* Substitute into the rest of the list. */
2423 new_spec_types =
2427 /* Add the default argument for this parameter. */
2430 new_spec_types);
2431 }
2433 /* DECL is an explicit specialization. Replicate default arguments
2434 from the template it specializes. (That way, code like:
2436 template <class T> void f(T = 3);
2437 template <> void f(double);
2438 void g () { f (); }
2440 works, as required.) An alternative approach would be to look up
2441 the correct default arguments at the call-site, but this approach
2442 is consistent with how implicit instantiations are handled. */
2444 static void
2446 {
2447 tree tmpl;
2448 tree spec_types;
2449 tree tmpl_types;
2450 tree new_spec_types;
2451 tree old_type;
2452 tree new_type;
2453 tree t;
2458 /* See if there's anything we need to do. */
2471 {
2472 /* Remove the this pointer, but remember the object's type for
2473 CV quals. */
2479 {
2480 /* DECL may contain more parameters than TMPL due to the extra
2481 in-charge parameter in constructors and destructors. */
2484 }
2486 {
2489 }
2490 }
2492 /* Compute the merged default arguments. */
2493 new_spec_types =
2496 /* Compute the new FUNCTION_TYPE. */
2498 {
2502 new_spec_types);
2505 /* Put the in-charge parameter back. */
2508 new_spec_types);
2512 new_spec_types);
2513 }
2514 else
2516 new_spec_types);
2526 }
2528 /* Return the number of template headers we expect to see for a definition
2529 or specialization of CTYPE or one of its non-template members. */
2531 int
2533 {
2537 {
2538 /* You're supposed to have one `template <...>' for every
2539 template class, but you don't need one for a full
2540 specialization. For example:
2542 template <class T> struct S{};
2543 template <> struct S<int> { void f(); };
2544 void S<int>::f () {}
2546 is correct; there shouldn't be a `template <>' for the
2547 definition of `S<int>::f'. */
2549 /* If CTYPE does not have template information of any
2550 kind, then it is not a template, nor is it nested
2551 within a template. */
2559 }
2562 }
2564 /* Do a simple sanity check on the template headers that precede the
2565 variable declaration DECL. */
2567 void
2569 {
2574 {
2577 "variable templates only available with "
2580 // Namespace-scope variable templates should have a template header.
2582 }
2584 {
2591 "members of an explicitly specialized class are defined "
2593 }
2594 }
2596 /* An explicit specialization whose declarator-id or class-head-name is not
2597 qualified shall be declared in the nearest enclosing namespace of the
2598 template, or, if the namespace is inline (7.3.1), any namespace from its
2599 enclosing namespace set.
2601 If the name declared in the explicit instantiation is an unqualified name,
2602 the explicit instantiation shall appear in the namespace where its template
2603 is declared or, if that namespace is inline (7.3.1), any namespace from its
2604 enclosing namespace set. */
2606 void
2608 {
2613 {
2619 /* This was allowed in C++98, so only pedwarn. */
2621 "outside its namespace must use a nested-name-"
2623 }
2624 }
2626 /* Check to see if the function just declared, as indicated in
2627 DECLARATOR, and in DECL, is a specialization of a function
2628 template. We may also discover that the declaration is an explicit
2629 instantiation at this point.
2631 Returns DECL, or an equivalent declaration that should be used
2632 instead if all goes well. Issues an error message if something is
2633 amiss. Returns error_mark_node if the error is not easily
2634 recoverable.
2636 FLAGS is a bitmask consisting of the following flags:
2638 2: The function has a definition.
2639 4: The function is a friend.
2641 The TEMPLATE_COUNT is the number of references to qualifying
2642 template classes that appeared in the name of the function. For
2643 example, in
2645 template <class T> struct S { void f(); };
2646 void S<int>::f();
2648 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2649 classes are not counted in the TEMPLATE_COUNT, so that in
2651 template <class T> struct S {};
2652 template <> struct S<int> { void f(); }
2653 template <> void S<int>::f();
2655 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2656 invalid; there should be no template <>.)
2658 If the function is a specialization, it is marked as such via
2659 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2660 is set up correctly, and it is added to the list of specializations
2661 for that template. */
2663 tree
2665 tree decl,
2668 {
2677 tmpl_spec_kind tsk;
2680 {
2683 else
2685 }
2686 else
2690 {
2693 {
2696 }
2698 {
2700 /* This could be something like:
2702 template <class T> void f(T);
2703 class S { friend void f<>(int); } */
2705 else
2706 {
2707 /* This case handles bogus declarations like template <>
2708 template <class T> void f<int>(); */
2711 declarator);
2713 }
2714 }
2718 /* The error has already been reported in
2719 check_specialization_scope. */
2725 /* Fall through. */
2738 decl);
2741 else
2745 /* Fall through. */
2751 /* In cases like template<> constexpr bool v = true;
2752 We'll give an error in check_template_variable. */
2758 else
2764 {
2765 /* This case handles bogus declarations like template <>
2766 template <class T> void f<int>(); */
2770 declarator);
2772 {
2773 /* Partial specialization of variable template. */
2777 }
2781 else
2785 ok:;
2786 }
2789 /* This is a specialization of a member template, without
2790 specialization the containing class. Something like:
2792 template <class T> struct S {
2793 template <class U> void f (U);
2794 };
2795 template <> template <class U> void S<int>::f(U) {}
2797 That's a specialization -- but of the entire template. */
2803 }
2806 /* This doesn't apply to variable templates. */
2809 {
2813 {
2817 }
2818 }
2821 {
2826 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2828 {
2829 tree fns;
2834 else
2835 {
2836 /* If there is no class context, the explicit instantiation
2837 must be at namespace scope. */
2840 /* Find the namespace binding, using the declaration
2841 context. */
2845 /* If lookup fails, look for a friend declaration so we can
2846 give a better diagnostic. */
2852 {
2855 }
2856 }
2859 }
2865 {
2867 /* A specialization in class scope. This is invalid,
2868 but the error will already have been flagged by
2869 check_specialization_scope. */
2871 else
2872 {
2873 /* It's not valid to write an explicit instantiation in
2874 class scope, e.g.:
2876 class C { template void f(); }
2878 This case is caught by the parser. However, on
2879 something like:
2881 template class C { void f(); };
2883 (which is invalid) we can get here. The error will be
2884 issued later. */
2885 ;
2886 }
2889 }
2892 {
2893 // We'll match variable templates in start_decl.
2897 /* Find the list of functions in ctype that have the same
2898 name as the declared function. */
2904 {
2909 {
2910 /* From [temp.expl.spec]:
2912 If such an explicit specialization for the member
2913 of a class template names an implicitly-declared
2914 special member function (clause _special_), the
2915 program is ill-formed.
2917 Similar language is found in [temp.explicit]. */
2920 }
2923 }
2926 {
2930 }
2931 else
2932 {
2934 tree ovl;
2936 /* For a type-conversion operator, we cannot do a
2937 name-based lookup. We might be looking for `operator
2938 int' which will be a specialization of `operator T'.
2939 So, we find *all* the conversion operators, and then
2940 select from them. */
2948 {
2950 /* There are no more conversion functions. */
2953 /* Glue all these conversion functions together
2954 with those we already have. */
2957 }
2958 }
2961 {
2964 }
2965 else
2967 }
2969 /* Figure out what exactly is being specialized at this point.
2970 Note that for an explicit instantiation, even one for a
2971 member function, we cannot tell a priori whether the
2972 instantiation is for a member template, or just a member
2973 function of a template class. Even if a member template is
2974 being instantiated, the member template arguments may be
2975 elided if they can be deduced from the rest of the
2976 declaration. */
2979 member_specialization,
2980 template_count,
2981 tsk);
2984 /* We couldn't figure out what this declaration was
2985 specializing. */
2987 else
2988 {
2991 {
2993 "friend declaration %qD is not visible to "
2997 }
3005 {
3006 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3007 is done by do_decl_instantiation later. */
3013 {
3014 /* If TMPL is not the most general template (for
3015 example, if TMPL is a friend template that is
3016 injected into namespace scope), then there will
3017 be too many levels of TARGS. Remove some of them
3018 here. */
3020 tree new_targs;
3027 }
3030 }
3032 /* If we thought that the DECL was a member function, but it
3033 turns out to be specializing a static member function,
3034 make DECL a static member function as well. */
3040 /* If this is a specialization of a member template of a
3041 template class, we want to return the TEMPLATE_DECL, not
3042 the specialization of it. */
3044 {
3049 {
3050 tree parm;
3054 /* We want to use the argument list specified in the
3055 definition, not in the original declaration. */
3060 }
3063 }
3065 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3071 /* Inherit default function arguments from the template
3072 DECL is specializing. */
3076 /* This specialization has the same protection as the
3077 template it specializes. */
3081 /* 7.1.1-1 [dcl.stc]
3083 A storage-class-specifier shall not be specified in an
3084 explicit specialization...
3086 The parser rejects these, so unless action is taken here,
3087 explicit function specializations will always appear with
3088 global linkage.
3090 The action recommended by the C++ CWG in response to C++
3091 defect report 605 is to make the storage class and linkage
3092 of the explicit specialization match the templated function:
3094 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3095 */
3097 {
3101 /* A concept cannot be specialized. */
3103 {
3105 gen_tmpl);
3107 }
3109 /* This specialization has the same linkage and visibility as
3110 the function template it specializes. */
3113 {
3116 }
3119 {
3122 }
3123 }
3125 /* If DECL is a friend declaration, declared using an
3126 unqualified name, the namespace associated with DECL may
3127 have been set incorrectly. For example, in:
3129 template <typename T> void f(T);
3130 namespace N {
3131 struct S { friend void f<int>(int); }
3132 }
3134 we will have set the DECL_CONTEXT for the friend
3135 declaration to N, rather than to the global namespace. */
3140 /* This is not really a declaration of a specialization.
3141 It's just the name of an instantiation. But, it's not
3142 a request for an instantiation, either. */
3145 /* A specialization is not necessarily COMDAT. */
3151 /* If this is a full specialization, register it so that we can find
3152 it again. Partial specializations will be registered in
3153 process_partial_specialization. */
3158 /* A 'structor should already have clones. */
3164 }
3165 }
3168 }
3170 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3171 parameters. These are represented in the same format used for
3172 DECL_TEMPLATE_PARMS. */
3174 int
3176 {
3177 const_tree p1;
3178 const_tree p2;
3186 {
3198 {
3202 /* If either of the template parameters are invalid, assume
3203 they match for the sake of error recovery. */
3216 }
3217 }
3220 /* One set of parameters has more parameters lists than the
3221 other. */
3225 }
3227 /* Determine whether PARM is a parameter pack. */
3229 bool
3231 {
3232 /* Determine if we have a non-type template parameter pack. */
3239 /* If this is a list of template parameters, we could get a
3240 TYPE_DECL or a TEMPLATE_DECL. */
3244 /* Otherwise it must be a type template parameter. */
3248 }
3250 /* Determine if T is a function parameter pack. */
3252 bool
3254 {
3258 }
3260 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3261 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3263 tree
3265 {
3272 }
3274 /* Return true iff the function parameter PARAM_DECL was expanded
3275 from the function parameter pack PACK. */
3277 bool
3279 {
3284 /* The parameter pack and its pack arguments have the same
3285 DECL_PARM_INDEX. */
3287 }
3289 /* Determine whether ARGS describes a variadic template args list,
3290 i.e., one that is terminated by a template argument pack. */
3292 static bool
3294 {
3296 tree last_parm;
3310 }
3312 /* Generate a new name for the parameter pack name NAME (an
3313 IDENTIFIER_NODE) that incorporates its */
3315 static tree
3317 {
3318 /* Munge the name to include the parameter index. */
3319 #define NUMBUF_LEN 128
3333 }
3335 /* Return true if T is a primary function, class or alias template
3336 instantiation. */
3338 bool
3340 {
3354 }
3356 /* Return true if PARM is a template template parameter. */
3358 bool
3360 {
3362 }
3364 /* Return true iff PARM is a DECL representing a type template
3365 parameter. */
3367 bool
3369 {
3374 }
3376 /* Return the template parameters of T if T is a
3377 primary template instantiation, NULL otherwise. */
3379 tree
3381 {
3386 parms = INNERMOST_TEMPLATE_PARMS
3390 }
3392 /* Return the template parameters of the LEVELth level from the full list
3393 of template parameters PARMS. */
3395 tree
3397 {
3398 tree p;
3409 }
3411 /* Returns the template arguments of T if T is a template instantiation,
3412 NULL otherwise. */
3414 tree
3416 {
3424 }
3426 /* Return the argument pack elements of T if T is a template argument pack,
3427 NULL otherwise. */
3429 tree
3431 {
3437 }
3439 /* Structure used to track the progress of find_parameter_packs_r. */
3440 struct find_parameter_pack_data
3441 {
3442 /* TREE_LIST that will contain all of the parameter packs found by
3443 the traversal. */
3446 /* Set of AST nodes that have been visited by the traversal. */
3449 /* True iff we're making a type pack expansion. */
3451 };
3453 /* Identifies all of the argument packs that occur in a template
3454 argument and appends them to the TREE_LIST inside DATA, which is a
3455 find_parameter_pack_data structure. This is a subroutine of
3456 make_pack_expansion and uses_parameter_packs. */
3457 static tree
3459 {
3465 /* Handle type aliases/typedefs. */
3467 {
3474 }
3476 /* Identify whether this is a parameter pack or not. */
3478 {
3486 /* FALLTHRU */
3488 /* If the placeholder appears in the decl-specifier-seq of a function
3489 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3490 is a pack expansion, the invented template parameter is a template
3491 parameter pack. */
3501 {
3502 /* We don't want to walk into the type of a PARM_DECL,
3503 because we don't want to see the type parameter pack. */
3506 }
3509 /* Look through a lambda capture proxy to the field pack. */
3512 {
3518 }
3520 {
3522 find_parameter_packs_r,
3525 }
3532 /* Not a parameter pack. */
3534 }
3537 {
3538 /* Add this parameter pack to the list. */
3540 }
3546 /* This switch statement will return immediately if we don't find a
3547 parameter pack. */
3549 {
3554 /* Check the template itself. */
3557 /* Check the template arguments. */
3573 /* Fall through. */
3618 {
3619 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3620 type_pack_expansion_p to false so that any placeholders
3621 within the expression don't get marked as parameter packs. */
3629 }
3633 }
3636 }
3638 /* Determines if the expression or type T uses any parameter packs. */
3639 bool
3641 {
3650 }
3652 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3653 representation a base-class initializer into a parameter pack
3654 expansion. If all goes well, the resulting node will be an
3655 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3656 respectively. */
3657 tree
3659 {
3660 tree result;
3669 {
3670 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3671 class initializer. In this case, the TREE_PURPOSE will be a
3672 _TYPE node (representing the base class expansion we're
3673 initializing) and the TREE_VALUE will be a TREE_LIST
3674 containing the initialization arguments.
3676 The resulting expansion looks somewhat different from most
3677 expansions. Rather than returning just one _EXPANSION, we
3678 return a TREE_LIST whose TREE_PURPOSE is a
3679 TYPE_PACK_EXPANSION containing the bases that will be
3680 initialized. The TREE_VALUE will be identical to the
3681 original TREE_VALUE, which is a list of arguments that will
3682 be passed to each base. We do not introduce any new pack
3683 expansion nodes into the TREE_VALUE (although it is possible
3684 that some already exist), because the TREE_PURPOSE and
3685 TREE_VALUE all need to be expanded together with the same
3686 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3687 resulting TREE_PURPOSE will mention the parameter packs in
3688 both the bases and the arguments to the bases. */
3689 tree purpose;
3690 tree value;
3693 /* Determine which parameter packs will be used by the base
3694 class expansion. */
3703 {
3707 }
3710 {
3711 /* Collect the sets of parameter packs used in each of the
3712 initialization arguments. */
3714 {
3715 /* Determine which parameter packs will be expanded in this
3716 argument. */
3719 }
3720 }
3724 /* Create the pack expansion type for the base type. */
3729 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3730 they will rarely be compared to anything. */
3734 }
3739 /* Build the PACK_EXPANSION_* node. */
3740 result = for_types
3745 {
3746 /* Propagate type and const-expression information. */
3749 /* Mark this read now, since the expansion might be length 0. */
3751 }
3752 else
3753 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3754 they will rarely be compared to anything. */
3757 /* Determine which parameter packs will be expanded. */
3764 /* Make sure we found some parameter packs. */
3766 {
3769 else
3772 }
3778 }
3780 /* Checks T for any "bare" parameter packs, which have not yet been
3781 expanded, and issues an error if any are found. This operation can
3782 only be done on full expressions or types (e.g., an expression
3783 statement, "if" condition, etc.), because we could have expressions like:
3785 foo(f(g(h(args)))...)
3787 where "args" is a parameter pack. check_for_bare_parameter_packs
3788 should not be called for the subexpressions args, h(args),
3789 g(h(args)), or f(g(h(args))), because we would produce erroneous
3790 error messages.
3792 Returns TRUE and emits an error if there were bare parameter packs,
3793 returns FALSE otherwise. */
3794 bool
3796 {
3813 {
3817 {
3826 else
3831 else
3835 }
3838 }
3841 }
3843 /* Expand any parameter packs that occur in the template arguments in
3844 ARGS. */
3845 tree
3847 {
3856 /* First, determine if we need to expand anything, and the number of
3857 slots we'll need. */
3859 {
3864 {
3868 else
3870 }
3871 else
3872 {
3874 num_result_args++;
3875 }
3876 }
3878 /* If no expansion is necessary, we're done. */
3882 /* Expand arguments. */
3885 non_default_args_count =
3888 {
3891 {
3898 }
3899 else
3900 {
3903 }
3904 }
3908 }
3910 /* Checks if DECL shadows a template parameter.
3912 [temp.local]: A template-parameter shall not be redeclared within its
3913 scope (including nested scopes).
3915 Emits an error and returns TRUE if the DECL shadows a parameter,
3916 returns FALSE otherwise. */
3918 bool
3920 {
3921 tree olddecl;
3923 /* If we're not in a template, we can't possibly shadow a template
3924 parameter. */
3928 /* Figure out what we're shadowing. */
3933 /* If there's no previous binding for this name, we're not shadowing
3934 anything, let alone a template parameter. */
3938 /* If we're not shadowing a template parameter, we're done. Note
3939 that OLDDECL might be an OVERLOAD (or perhaps even an
3940 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3941 node. */
3945 /* We check for decl != olddecl to avoid bogus errors for using a
3946 name inside a class. We check TPFI to avoid duplicate errors for
3947 inline member templates. */
3953 /* Don't complain about the injected class name, as we've already
3954 complained about the class itself. */
3961 else
3966 }
3968 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3969 ORIG_LEVEL, DECL, and TYPE. */
3971 static tree
3975 tree decl,
3976 tree type)
3977 {
3988 }
3990 /* Find the canonical type parameter for the given template type
3991 parameter. Returns the canonical type parameter, which may be TYPE
3992 if no such parameter existed. */
3994 static tree
3996 {
3997 tree list;
4011 else
4012 {
4016 }
4017 }
4019 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4020 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4021 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4022 new one is created. */
4024 static tree
4026 tsubst_flags_t complain)
4027 {
4032 {
4051 /* Template template parameters need this. */
4053 {
4060 }
4061 }
4064 }
4066 /* Process information from new template parameter PARM and append it
4067 to the LIST being built. This new parameter is a non-type
4068 parameter iff IS_NON_TYPE is true. This new parameter is a
4069 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4070 is in PARM_LOC. */
4072 tree
4075 {
4084 {
4088 {
4092 else
4094 }
4097 }
4100 {
4106 {
4107 /* [temp.param]
4109 The top-level cv-qualifiers on the template-parameter are
4110 ignored when determining its type. */
4115 && !is_parameter_pack
4116 /* If we're in a nested template parameter list, the template
4117 template parameter could be a parameter pack. */
4119 {
4120 /* This template parameter is not a parameter pack, but it
4121 should be. Complain about "bare" parameter packs. */
4124 /* Recover by calling this a parameter pack. */
4126 }
4127 }
4129 /* A template parameter is not modifiable. */
4138 processing_template_decl,
4143 }
4144 else
4145 {
4146 tree t;
4150 {
4152 /* This is for distinguishing between real templates and template
4153 template parameters */
4157 }
4158 else
4159 {
4161 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4164 }
4171 processing_template_decl,
4175 }
4179 /* Build requirements for the type/template parameter.
4180 This must be done after SET_DECL_TEMPLATE_PARM_P or
4181 process_template_parm could fail. */
4186 /* Build the parameter node linking the parameter declaration,
4187 its default argument (if any), and its constraints (if any). */
4192 }
4194 /* The end of a template parameter list has been reached. Process the
4195 tree list into a parameter vector, converting each parameter into a more
4196 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4197 as PARM_DECLs. */
4199 tree
4201 {
4206 /* Pop the dummy parameter level and add the real one. */
4209 current_template_parms
4214 {
4218 }
4223 }
4225 // Explicitly indicate the end of the template parameter list. We assume
4226 // that the current template parameters have been constructed and/or
4227 // managed explicitly, as when creating new template template parameters
4228 // from a shorthand constraint.
4229 void
4231 {
4233 }
4235 /* end_template_decl is called after a template declaration is seen. */
4237 void
4239 {
4245 /* This matches the pushlevel in begin_template_parm_list. */
4250 }
4252 /* Takes a TREE_LIST representing a template parameter and convert it
4253 into an argument suitable to be passed to the type substitution
4254 functions. Note that If the TREE_LIST contains an error_mark
4255 node, the returned argument is error_mark_node. */
4257 tree
4259 {
4272 {
4276 {
4277 /* Turn this argument into a TYPE_ARGUMENT_PACK
4278 with a single element, which expands T. */
4287 }
4288 }
4289 else
4290 {
4294 {
4295 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4296 with a single element, which expands T. */
4308 }
4309 else
4311 }
4313 }
4315 /* Given a single level of template parameters (a TREE_VEC), return it
4316 as a set of template arguments. */
4318 static tree
4320 {
4330 }
4332 /* Given a set of template parameters, return them as a set of template
4333 arguments. The template parameters are represented as a TREE_VEC, in
4334 the form documented in cp-tree.h for template arguments. */
4336 static tree
4338 {
4339 tree header;
4344 /* If there is only one level of template parameters, we do not
4345 create a TREE_VEC of TREE_VECs. Instead, we return a single
4346 TREE_VEC containing the arguments. */
4351 {
4356 else
4358 }
4361 }
4363 /* Within the declaration of a template, return the currently active
4364 template parameters as an argument TREE_VEC. */
4366 static tree
4368 {
4370 }
4372 /* Update the declared TYPE by doing any lookups which were thought to be
4373 dependent, but are not now that we know the SCOPE of the declarator. */
4375 tree
4377 {
4388 /* Don't bother building up the args in this case. */
4390 {
4391 /* tsubst in the args corresponding to the template parameters,
4392 including auto if present. Most things will be unchanged, but
4393 make_typename_type and tsubst_qualified_id will resolve
4394 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4397 tree pushed;
4399 {
4403 }
4408 }
4414 {
4417 else
4419 }
4421 }
4423 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4424 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4425 the new template is a member template. */
4427 tree
4429 {
4437 }
4439 struct template_parm_data
4440 {
4441 /* The level of the template parameters we are currently
4442 processing. */
4445 /* The index of the specialization argument we are currently
4446 processing. */
4449 /* An array whose size is the number of template parameters. The
4450 elements are nonzero if the parameter has been used in any one
4451 of the arguments processed so far. */
4454 /* An array whose size is the number of template arguments. The
4455 elements are nonzero if the argument makes use of template
4456 parameters of this level. */
4458 };
4460 /* Subroutine of push_template_decl used to see if each template
4461 parameter in a partial specialization is used in the explicit
4462 argument list. If T is of the LEVEL given in DATA (which is
4463 treated as a template_parm_data*), then DATA->PARMS is marked
4464 appropriately. */
4466 static int
4468 {
4476 {
4479 }
4481 /* In C++17 the type of a non-type argument is a deduced context. */
4486 data,
4487 NULL,
4490 /* Return zero so that for_each_template_parm will continue the
4491 traversal of the tree; we want to mark *every* template parm. */
4493 }
4495 /* Process the partial specialization DECL. */
4497 static tree
4499 {
4506 tree inner_parms;
4507 tree inst;
4517 /* A concept cannot be specialized. */
4519 {
4522 }
4527 /* We check that each of the template parameters given in the
4528 partial specialization is used in the argument list to the
4529 specialization. For example:
4531 template <class T> struct S;
4532 template <class T> struct S<T*>;
4534 The second declaration is OK because `T*' uses the template
4535 parameter T, whereas
4537 template <class T> struct S<int>;
4539 is no good. Even trickier is:
4541 template <class T>
4542 struct S1
4543 {
4544 template <class U>
4545 struct S2;
4546 template <class U>
4547 struct S2<T>;
4548 };
4550 The S2<T> declaration is actually invalid; it is a
4551 full-specialization. Of course,
4553 template <class U>
4554 struct S2<T (*)(U)>;
4556 or some such would have been OK. */
4564 {
4569 NULL,
4571 }
4574 {
4575 /* One of the template parms was not used in a deduced context in the
4576 specialization. */
4578 {
4582 }
4586 }
4591 /* [temp.class.spec]
4593 The argument list of the specialization shall not be identical to
4594 the implicit argument list of the primary template. */
4595 tree main_args
4598 && (!flag_concepts
4601 {
4605 else
4609 }
4611 /* A partial specialization that replaces multiple parameters of the
4612 primary template with a pack expansion is less specialized for those
4613 parameters. */
4615 {
4617 "primary template because it replaces multiple parameters "
4620 /* Avoid crash in process_partial_specialization. */
4622 }
4624 /* If we aren't in a dependent class, we can actually try deduction. */
4626 /* FIXME we should be able to handle a partial specialization of a
4627 partial instantiation, but currently we can't (c++/41727). */
4630 {
4634 maintmpl);
4635 }
4637 /* [temp.class.spec]
4639 A partially specialized non-type argument expression shall not
4640 involve template parameters of the partial specialization except
4641 when the argument expression is a simple identifier.
4643 The type of a template parameter corresponding to a specialized
4644 non-type argument shall not be dependent on a parameter of the
4645 specialization.
4647 Also, we verify that pack expansions only occur at the
4648 end of the argument list. */
4652 {
4659 {
4660 /* Extract the arguments from the argument pack. We'll be
4661 iterating over these in the following loop. */
4664 }
4667 {
4669 /* Get the Jth argument in the parameter pack. */
4673 {
4674 /* Pack expansions must come at the end of the
4675 argument list. */
4678 {
4682 else
4685 }
4686 }
4689 /* We only care about the pattern. */
4695 /* This next two lines are the `argument expression is not just a
4696 simple identifier' condition and also the `specialized
4697 non-type argument' bit. */
4701 {
4705 arg);
4706 else
4707 {
4708 /* Look at the corresponding template parameter,
4709 marking which template parameters its type depends
4710 upon. */
4714 {
4715 /* We haven't yet initialized TPD2. Do so now. */
4717 /* The number of parameters here is the number in the
4718 main template, which, as checked in the assertion
4719 above, is NARGS. */
4723 }
4725 /* Mark the template parameters. But this time, we're
4726 looking for the template parameters of the main
4727 template, not in the specialization. */
4734 NULL,
4738 {
4739 /* The type depended on some template parameters.
4740 If they are fully specialized in the
4741 specialization, that's OK. */
4750 "type %qT of template argument %qE depends "
4752 "type %qT of template argument %qE depends "
4754 type,
4755 arg);
4756 }
4757 }
4758 }
4759 }
4760 }
4762 /* We should only get here once. */
4766 // Build the template decl.
4775 /* Give template template parms a DECL_CONTEXT of the template
4776 for which they are a parameter. */
4778 {
4782 }
4785 /* We didn't register this in check_explicit_specialization so we could
4786 wait until the constraints were set. */
4788 else
4798 {
4804 {
4812 "declaration of %qD ambiguates earlier template "
4816 "partial specialization of %qD after instantiation "
4818 }
4819 }
4822 }
4824 /* PARM is a template parameter of some form; return the corresponding
4825 TEMPLATE_PARM_INDEX. */
4827 static tree
4829 {
4842 }
4844 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4845 parameter packs used by the template parameter PARM. */
4847 static void
4849 {
4850 /* A type parm can't refer to another parm. */
4854 {
4858 }
4865 }
4867 /* PARM is a template parameter pack. Return any parameter packs used in
4868 its type or the type of any of its template parameters. If there are
4869 any such packs, it will be instantiated into a fixed template parameter
4870 list by partial instantiation rather than be fully deduced. */
4872 tree
4874 {
4875 /* This can only be true in a member template. */
4878 /* This can only be true for a parameter pack. */
4881 /* A type parm can't refer to another parm. */
4895 }
4897 /* Check that a template declaration's use of default arguments and
4898 parameter packs is not invalid. Here, PARMS are the template
4899 parameters. IS_PRIMARY is true if DECL is the thing declared by
4900 a primary template. IS_PARTIAL is true if DECL is a partial
4901 specialization.
4903 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4904 declaration (but not a definition); 1 indicates a declaration, 2
4905 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4906 emitted for extraneous default arguments.
4908 Returns TRUE if there were no errors found, FALSE otherwise. */
4910 bool
4913 {
4916 tree parm_level;
4919 /* [temp.param]
4921 A default template-argument shall not be specified in a
4922 function template declaration or a function template definition, nor
4923 in the template-parameter-list of the definition of a member of a
4924 class template. */
4928 /* You can't have a function template declaration in a local
4929 scope, nor you can you define a member of a class template in a
4930 local scope. */
4938 /* A lambda doesn't have an explicit declaration; don't complain
4939 about the parms of the enclosing class. */
4946 /* If this is either a friend defined in the scope of the class
4947 or a member function. */
4953 /* And, if it was a member function, it really was defined in
4954 the scope of the class. */
4957 /* We already checked these parameters when the template was
4958 declared, so there's no need to do it again now. This function
4959 was defined in class scope, but we're processing its body now
4960 that the class is complete. */
4963 /* Core issue 226 (C++0x only): the following only applies to class
4964 templates. */
4967 {
4968 /* [temp.param]
4970 If a template-parameter has a default template-argument, all
4971 subsequent template-parameters shall have a default
4972 template-argument supplied. */
4974 {
4981 {
4991 {
4993 /* For better subsequent error-recovery, we indicate that
4994 there should have been a default argument. */
4997 }
4999 && !is_friend_decl
5000 /* Don't complain about an enclosing partial
5001 specialization. */
5006 /* A fixed parameter pack will be partially
5007 instantiated into a fixed length list. */
5009 {
5010 /* A primary class template can only have one
5011 parameter pack, at the end of the template
5012 parameter list. */
5020 }
5021 }
5022 }
5023 }
5026 || is_partial
5027 || !is_primary
5029 /* For an ordinary class template, default template arguments are
5030 allowed at the innermost level, e.g.:
5031 template <class T = int>
5032 struct S {};
5033 but, in a partial specialization, they're not allowed even
5034 there, as we have in [temp.class.spec]:
5036 The template parameter list of a specialization shall not
5037 contain default template argument values.
5039 So, for a partial specialization, or for a function template
5040 (in C++98/C++03), we look at all of them. */
5041 ;
5042 else
5043 /* But, for a primary class template that is not a partial
5044 specialization we look at all template parameters except the
5045 innermost ones. */
5048 /* Figure out what error message to issue. */
5063 else
5064 /* Per [temp.param]/9, "A default template-argument shall not be
5065 specified in the template-parameter-lists of the definition of
5066 a member of a class template that appears outside of the member's
5067 class.", thus if we aren't handling a member of a class template
5068 there is no need to examine the parameters. */
5072 /* If we're inside a class definition, there's no need to
5073 examine the parameters to the class itself. On the one
5074 hand, they will be checked when the class is defined, and,
5075 on the other, default arguments are valid in things like:
5076 template <class T = double>
5077 struct S { template <class U> void f(U); };
5078 Here the default argument for `S' has no bearing on the
5079 declaration of `f'. */
5081 else
5082 /* Check everything. */
5088 {
5095 {
5100 {
5102 {
5109 }
5111 /* Clear out the default argument so that we are not
5112 confused later. */
5114 }
5115 }
5117 /* At this point, if we're still interested in issuing messages,
5118 they must apply to classes surrounding the object declared. */
5122 }
5125 }
5127 /* Worker for push_template_decl_real, called via
5128 for_each_template_parm. DATA is really an int, indicating the
5129 level of the parameters we are interested in. If T is a template
5130 parameter of that level, return nonzero. */
5132 static int
5134 {
5140 else
5143 }
5145 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5146 DATA is really an int, indicating the innermost outer level of parameters.
5147 If T is a template parameter of that level or further out, return
5148 nonzero. */
5150 static int
5152 {
5158 else
5161 }
5163 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5164 parameters given by current_template_args, or reuses a
5165 previously existing one, if appropriate. Returns the DECL, or an
5166 equivalent one, if it is replaced via a call to duplicate_decls.
5168 If IS_FRIEND is true, DECL is a friend declaration. */
5170 tree
5172 {
5173 tree tmpl;
5174 tree args;
5175 tree info;
5176 tree ctx;
5180 /* True if the template is a member template, in the sense of
5181 [temp.mem]. */
5187 /* See if this is a partial specialization. */
5200 /* For a friend, we want the context of the friend function, not
5201 the type of which it is a friend. */
5205 /* In the case of a virtual function, we want the class in which
5206 it is defined. */
5208 else
5209 /* Otherwise, if we're currently defining some class, the DECL
5210 is assumed to be a member of the class. */
5219 /* See if this is a primary template. */
5222 /* A friend template that specifies a class context, i.e.
5223 template <typename T> friend void A<T>::f();
5224 is not primary. */
5229 else
5233 {
5240 {
5243 }
5245 {
5247 {
5250 }
5252 {
5253 /* [temp.mem]
5255 A destructor shall not be a member template. */
5258 }
5265 {
5266 /* [basic.stc.dynamic.allocation]
5268 An allocation function can be a function
5269 template. ... Template allocation functions shall
5270 have two or more parameters. */
5273 }
5274 }
5277 {
5278 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5281 {
5287 }
5288 }
5291 /* alias-declaration */
5295 else
5296 {
5299 }
5300 }
5302 /* Check to see that the rules regarding the use of default
5303 arguments are not being violated. */
5307 /* Ensure that there are no parameter packs in the type of this
5308 declaration that have not been expanded. */
5310 {
5311 /* Check each of the arguments individually to see if there are
5312 any bare parameter packs. */
5318 {
5321 {
5322 /* This is a PARM_DECL that contains unexpanded parameter
5323 packs. We have already complained about this in the
5324 check_for_bare_parameter_packs call, so just replace
5325 these types with ERROR_MARK_NODE. */
5328 }
5332 }
5334 /* Check for bare parameter packs in the return type and the
5335 exception specifiers. */
5337 /* Errors were already issued, set return type to int
5338 as the frontend doesn't expect error_mark_node as
5339 the return type. */
5343 }
5348 {
5351 }
5364 {
5369 /* If DECL is a TYPE_DECL for a class-template, then there won't
5370 be DECL_LANG_SPECIFIC. The information equivalent to
5371 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5375 {
5376 /* Since a template declaration already existed for this
5377 class-type, we must be redeclaring it here. Make sure
5378 that the redeclaration is valid. */
5380 current_template_parms,
5382 /* We don't need to create a new TEMPLATE_DECL; just use the
5383 one we already had. */
5385 }
5386 else
5387 {
5389 member_template_p);
5394 {
5395 /* A specialization of a member template of a template
5396 class. */
5400 }
5401 }
5402 }
5403 else
5404 {
5410 {
5413 }
5421 {
5422 tree new_tmpl;
5424 /* The declaration is a specialization of a member
5425 template, declared outside the class. Therefore, the
5426 innermost template arguments will be NULL, so we
5427 replace them with the arguments determined by the
5428 earlier call to check_explicit_specialization. */
5431 new_tmpl
5433 member_template_p);
5443 args,
5446 }
5448 /* Make sure the template headers we got make sense. */
5453 {
5458 }
5459 else
5461 {
5466 {
5470 else
5474 /* Avoid crash in import_export_decl. */
5477 }
5482 /* Can happen in erroneous input. */
5484 else
5486 }
5488 /* Check that the parms are used in the appropriate qualifying scopes
5489 in the declarator. */
5493 {
5499 /* Avoid crash in import_export_decl. */
5502 }
5503 }
5508 /* Push template declarations for global functions and types. Note
5509 that we do not try to push a global template friend declared in a
5510 template class; such a thing may well depend on the template
5511 parameters of the class. */
5514 {
5519 /* Hide template friend classes that haven't been declared yet. */
5521 {
5524 }
5525 }
5528 {
5534 {
5537 /* It is a conversion operator. See if the type converted to
5538 depends on innermost template operands. */
5541 depth))
5543 }
5545 /* Give template template parms a DECL_CONTEXT of the template
5546 for which they are a parameter. */
5549 {
5553 }
5559 }
5561 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5562 back to its most general template. If TMPL is a specialization,
5563 ARGS may only have the innermost set of arguments. Add the missing
5564 argument levels if necessary. */
5572 else
5573 {
5578 }
5581 && !is_friend
5584 /* Set DECL_COMDAT on template instantiations; if we force
5585 them to be emitted by explicit instantiation or -frepo,
5586 mark_needed will tell cgraph to do the right thing. */
5590 }
5592 tree
5594 {
5596 }
5598 /* FN is an inheriting constructor that inherits from the constructor
5599 template INHERITED; turn FN into a constructor template with a matching
5600 template header. */
5602 tree
5604 {
5605 tree inner_parms
5608 tree parms
5619 }
5621 /* Called when a class template TYPE is redeclared with the indicated
5622 template PARMS, e.g.:
5624 template <class T> struct S;
5625 template <class T> struct S {}; */
5627 bool
5629 {
5630 tree tmpl;
5631 tree tmpl_parms;
5635 {
5638 }
5642 /* The type is nested in some template class. Nothing to worry
5643 about here; there are no new template parameters for the nested
5644 type. */
5648 {
5650 tmpl);
5652 }
5658 {
5668 }
5671 {
5672 tree tmpl_parm;
5673 tree parm;
5674 tree tmpl_default;
5675 tree parm_default;
5689 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5690 TEMPLATE_DECL. */
5700 {
5704 }
5707 {
5708 /* We have in [temp.param]:
5710 A template-parameter may not be given default arguments
5711 by two different declarations in the same scope. */
5716 }
5719 /* Update the previous template parameters (which are the ones
5720 that will really count) with the new default value. */
5723 /* Update the new parameters, too; they'll be used as the
5724 parameters for any members. */
5727 /* Give each template template parm in this redeclaration a
5728 DECL_CONTEXT of the template for which they are a parameter. */
5730 {
5733 }
5737 }
5739 // Cannot redeclare a class template with a different set of constraints.
5741 {
5746 }
5749 }
5751 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5752 to be used when the caller has already checked
5753 (processing_template_decl
5754 && !instantiation_dependent_expression_p (expr)
5755 && potential_constant_expression (expr))
5756 and cleared processing_template_decl. */
5758 tree
5760 {
5763 complain,
5767 }
5769 /* Simplify EXPR if it is a non-dependent expression. Returns the
5770 (possibly simplified) expression. */
5772 tree
5774 {
5778 /* If we're in a template, but EXPR isn't value dependent, simplify
5779 it. We're supposed to treat:
5781 template <typename T> void f(T[1 + 1]);
5782 template <typename T> void f(T[2]);
5784 as two declarations of the same function, for example. */
5787 {
5788 processing_template_decl_sentinel s;
5790 }
5792 }
5794 tree
5796 {
5798 }
5800 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5801 an uninstantiated expression. */
5803 tree
5805 {
5809 {
5812 else
5813 {
5814 processing_template_decl_sentinel s;
5816 }
5817 }
5819 }
5821 /* True iff T is a specialization of a variable template. */
5823 bool
5825 {
5830 }
5832 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5833 template declaration, or a TYPE_DECL for an alias declaration. */
5835 bool
5837 {
5845 }
5847 /* Return TRUE iff T is a specialization of an alias template. */
5849 bool
5851 {
5852 /* It's an alias template specialization if it's an alias and its
5853 TYPE_NAME is a specialization of a primary template. */
5859 }
5861 /* An alias template is complex from a SFINAE perspective if a template-id
5862 using that alias can be ill-formed when the expansion is not, as with
5863 the void_t template. We determine this by checking whether the
5864 expansion for the alias template uses all its template parameters. */
5866 struct uses_all_template_parms_data
5867 {
5870 };
5872 static int
5874 {
5882 }
5884 static bool
5886 {
5901 }
5903 /* Return TRUE iff T is a specialization of a complex alias template with
5904 dependent template-arguments. */
5906 bool
5908 {
5921 }
5923 /* Return the number of innermost template parameters in TMPL. */
5925 static int
5927 {
5930 }
5932 /* Return either TMPL or another template that it is equivalent to under DR
5933 1286: An alias that just changes the name of a template is equivalent to
5934 the other template. */
5936 static tree
5938 {
5941 {
5942 /* Determine if the alias is equivalent to an underlying template. */
5954 tree alias_args = INNERMOST_TEMPLATE_ARGS
5959 /* Alias is equivalent. Strip it and repeat. */
5961 }
5964 }
5966 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5967 must be a reference-to-function or a pointer-to-function type, as specified
5968 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5969 and check that the resulting function has external linkage. */
5971 static tree
5973 tsubst_flags_t complain)
5974 {
5977 linkage_kind linkage;
5992 /* [temp.arg.nontype]/1
5994 A template-argument for a non-type, non-template template-parameter
5995 shall be one of:
5996 [...]
5997 -- the address of an object or function with external [C++11: or
5998 internal] linkage. */
6001 {
6003 {
6009 else
6012 }
6014 }
6018 {
6020 {
6025 else
6029 }
6031 }
6033 accept:
6040 }
6042 /* Subroutine of convert_nontype_argument.
6043 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6044 Emit an error otherwise. */
6046 static bool
6048 tsubst_flags_t complain)
6049 {
6060 {
6064 }
6066 }
6068 /* Returns TRUE iff the address of OP is value-dependent.
6070 14.6.2.4 [temp.dep.temp]:
6071 A non-integral non-type template-argument is dependent if its type is
6072 dependent or it has either of the following forms
6073 qualified-id
6074 & qualified-id
6075 and contains a nested-name-specifier which specifies a class-name that
6076 names a dependent type.
6078 We generalize this to just say that the address of a member of a
6079 dependent class is value-dependent; the above doesn't cover the
6080 address of a static data member named with an unqualified-id. */
6082 static bool
6084 {
6085 /* We could use get_inner_reference here, but there's no need;
6086 this is only relevant for template non-type arguments, which
6087 can only be expressed as &id-expression. */
6089 {
6093 }
6096 }
6098 /* The next set of functions are used for providing helpful explanatory
6099 diagnostics for failed overload resolution. Their messages should be
6100 indented by two spaces for consistency with the messages in
6101 call.c */
6103 static int
6105 {
6107 }
6109 static int
6111 {
6116 }
6118 static int
6120 {
6122 }
6124 static int
6126 {
6132 }
6134 static int
6136 {
6140 }
6142 static int
6144 {
6147 " template parameter %qD is not a parameter pack, but "
6151 }
6153 static int
6155 {
6158 " template argument %qE does not match "
6162 }
6164 static int
6166 {
6170 }
6172 static int
6174 {
6180 }
6182 static int
6184 {
6186 {
6191 else
6193 " deduced conflicting values for non-type parameter "
6195 }
6197 }
6199 static int
6201 {
6204 " variable-sized array type %qT is not "
6206 arg);
6208 }
6210 static int
6212 {
6216 arg);
6218 }
6220 static int
6222 {
6224 {
6230 else
6235 }
6237 }
6239 static int
6241 {
6243 }
6245 static int
6248 {
6250 }
6252 static int
6255 {
6261 }
6263 static int
6266 {
6269 {
6277 }
6279 }
6281 static int
6283 {
6286 " template parameters of a template template argument are "
6289 }
6291 static int
6293 {
6299 }
6301 static int
6303 {
6308 }
6310 static int
6312 {
6316 arg);
6318 }
6320 /* Attempt to convert the non-type template parameter EXPR to the
6321 indicated TYPE. If the conversion is successful, return the
6322 converted value. If the conversion is unsuccessful, return
6323 NULL_TREE if we issued an error message, or error_mark_node if we
6324 did not. We issue error messages for out-and-out bad template
6325 parameters, but not simply because the conversion failed, since we
6326 might be just trying to do argument deduction. Both TYPE and EXPR
6327 must be non-dependent.
6329 The conversion follows the special rules described in
6330 [temp.arg.nontype], and it is much more strict than an implicit
6331 conversion.
6333 This function is called twice for each template argument (see
6334 lookup_template_class for a more accurate description of this
6335 problem). This means that we need to handle expressions which
6336 are not valid in a C++ source, but can be created from the
6337 first call (for instance, casts to perform conversions). These
6338 hacks can go away after we fix the double coercion problem. */
6340 static tree
6342 {
6343 tree expr_type;
6345 /* Detect immediately string literals as invalid non-type argument.
6346 This special-case is not needed for correctness (we would easily
6347 catch this later), but only to provide better diagnostic for this
6348 common user mistake. As suggested by DR 100, we do not mention
6349 linkage issues in the diagnostic as this is not the point. */
6350 /* FIXME we're making this OK. */
6352 {
6358 }
6360 /* Add the ADDR_EXPR now for the benefit of
6361 value_dependent_expression_p. */
6364 {
6368 }
6370 /* If we are in a template, EXPR may be non-dependent, but still
6371 have a syntactic, rather than semantic, form. For example, EXPR
6372 might be a SCOPE_REF, rather than the VAR_DECL to which the
6373 SCOPE_REF refers. Preserving the qualifying scope is necessary
6374 so that access checking can be performed when the template is
6375 instantiated -- but here we need the resolved form so that we can
6376 convert the argument. */
6389 else
6392 /* If the argument is non-dependent, perform any conversions in
6393 non-dependent context as well. */
6401 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6402 to a non-type argument of "nullptr". */
6406 /* In C++11, integral or enumeration non-type template arguments can be
6407 arbitrary constant expressions. Pointer and pointer to
6408 member arguments can be general constant expressions that evaluate
6409 to a null value, but otherwise still need to be of a specific form. */
6411 {
6413 /* A PTRMEM_CST is already constant, and a valid template
6414 argument for a parameter of pointer to member type, we just want
6415 to leave it in that form rather than lower it to a
6420 {
6424 {
6428 }
6429 }
6431 {
6436 }
6437 }
6439 /* HACK: Due to double coercion, we can get a
6440 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6441 which is the tree that we built on the first call (see
6442 below when coercing to reference to object or to reference to
6443 function). We just strip everything and get to the arg.
6444 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6445 for examples. */
6447 {
6453 {
6454 /* ??? Maybe we could use convert_from_reference here, but we
6455 would need to relax its constraints because the NOP_EXPR
6456 could actually change the type to something more cv-qualified,
6457 and this is not folded by convert_from_reference. */
6462 && (same_type_ignoring_top_level_qualifiers_p
6465 {
6468 }
6469 }
6470 }
6472 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6473 parameter is a pointer to object, through decay and
6474 qualification conversion. Let's strip everything. */
6476 {
6481 {
6482 /* Skip the ADDR_EXPR only if it is part of the decay for
6483 an array. Otherwise, it is part of the original argument
6484 in the source code. */
6489 }
6490 }
6492 /* [temp.arg.nontype]/5, bullet 1
6494 For a non-type template-parameter of integral or enumeration type,
6495 integral promotions (_conv.prom_) and integral conversions
6496 (_conv.integral_) are applied. */
6498 {
6507 /* Notice that there are constant expressions like '4 % 0' which
6508 do not fold into integer constants. */
6511 {
6513 {
6524 /* else cxx_constant_value complained but gave us
6525 a real constant, so go ahead. */
6527 }
6528 else
6530 }
6532 /* Avoid typedef problems. */
6535 }
6536 /* [temp.arg.nontype]/5, bullet 2
6538 For a non-type template-parameter of type pointer to object,
6539 qualification conversions (_conv.qual_) and the array-to-pointer
6540 conversion (_conv.array_) are applied. */
6542 {
6543 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6545 A template-argument for a non-type, non-template template-parameter
6546 shall be one of: [...]
6548 -- the name of a non-type template-parameter;
6549 -- the address of an object or function with external linkage, [...]
6550 expressed as "& id-expression" where the & is optional if the name
6551 refers to a function or array, or if the corresponding
6552 template-parameter is a reference.
6554 Here, we do not care about functions, as they are invalid anyway
6555 for a parameter of type pointer-to-object. */
6558 /* Non-type template parameters are OK. */
6559 ;
6564 {
6566 {
6569 "because %qD is a variable, not the address of "
6572 }
6574 {
6580 }
6581 /* Other values, like integer constants, might be valid
6582 non-type arguments of some other type. */
6584 }
6585 else
6586 {
6587 tree decl;
6592 {
6597 }
6599 {
6605 }
6607 {
6612 }
6613 }
6622 }
6623 /* [temp.arg.nontype]/5, bullet 3
6625 For a non-type template-parameter of type reference to object, no
6626 conversions apply. The type referred to by the reference may be more
6627 cv-qualified than the (otherwise identical) type of the
6628 template-argument. The template-parameter is bound directly to the
6629 template-argument, which must be an lvalue. */
6631 {
6633 expr_type))
6637 {
6642 }
6645 {
6650 }
6652 /* [temp.arg.nontype]/1
6654 A template-argument for a non-type, non-template template-parameter
6655 shall be one of: [...]
6657 -- the address of an object or function with external linkage. */
6660 {
6663 {
6666 "because a reference variable does not have a constant "
6669 }
6670 }
6673 {
6675 {
6681 }
6683 /* DR 1155 allows internal linkage in C++11 and up. */
6686 {
6692 }
6695 }
6696 }
6697 /* [temp.arg.nontype]/5, bullet 4
6699 For a non-type template-parameter of type pointer to function, only
6700 the function-to-pointer conversion (_conv.func_) is applied. If the
6701 template-argument represents a set of overloaded functions (or a
6702 pointer to such), the matching function is selected from the set
6703 (_over.over_). */
6705 {
6706 /* If the argument is a template-id, we might not have enough
6707 context information to decay the pointer. */
6709 {
6713 }
6716 /* Null pointer values are OK in C++11. */
6722 }
6723 /* [temp.arg.nontype]/5, bullet 5
6725 For a non-type template-parameter of type reference to function, no
6726 conversions apply. If the template-argument represents a set of
6727 overloaded functions, the matching function is selected from the set
6728 (_over.over_). */
6730 {
6732 {
6734 {
6739 }
6741 }
6746 }
6747 /* [temp.arg.nontype]/5, bullet 6
6749 For a non-type template-parameter of type pointer to member function,
6750 no conversions apply. If the template-argument represents a set of
6751 overloaded member functions, the matching member function is selected
6752 from the set (_over.over_). */
6754 {
6759 /* [temp.arg.nontype] bullet 1 says the pointer to member
6760 expression must be a pointer-to-member constant. */
6765 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6766 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6770 /* There is no way to disable standard conversions in
6771 resolve_address_of_overloaded_function (called by
6772 instantiate_type). It is possible that the call succeeded by
6773 converting &B::I to &D::I (where B is a base of D), so we need
6774 to reject this conversion here.
6776 Actually, even if there was a way to disable standard conversions,
6777 it would still be better to reject them here so that we can
6778 provide a superior diagnostic. */
6780 {
6782 {
6786 /* If we are just one standard conversion off, explain. */
6790 }
6792 }
6793 }
6794 /* [temp.arg.nontype]/5, bullet 7
6796 For a non-type template-parameter of type pointer to data member,
6797 qualification conversions (_conv.qual_) are applied. */
6799 {
6800 /* [temp.arg.nontype] bullet 1 says the pointer to member
6801 expression must be a pointer-to-member constant. */
6809 }
6811 {
6813 {
6818 }
6820 }
6821 /* A template non-type parameter must be one of the above. */
6822 else
6825 /* Sanity check: did we actually convert the argument to the
6826 right type? */
6830 }
6832 /* Subroutine of coerce_template_template_parms, which returns 1 if
6833 PARM_PARM and ARG_PARM match using the rule for the template
6834 parameters of template template parameters. Both PARM and ARG are
6835 template parameters; the rest of the arguments are the same as for
6836 coerce_template_template_parms.
6837 */
6838 static int
6840 tree arg,
6841 tsubst_flags_t complain,
6842 tree in_decl,
6843 tree outer_args)
6844 {
6853 {
6855 /* We encounter instantiations of templates like
6856 template <template <template <class> class> class TT>
6857 class C; */
6858 {
6865 }
6866 /* Fall through. */
6871 /* Argument is a parameter pack but parameter is not. */
6876 /* The tsubst call is used to handle cases such as
6878 template <int> class C {};
6879 template <class T, template <T> class TT> class D {};
6880 D<int, C> d;
6882 i.e. the parameter list of TT depends on earlier parameters. */
6884 {
6889 }
6893 /* Argument is a parameter pack but parameter is not. */
6900 }
6903 }
6905 /* Coerce template argument list ARGLIST for use with template
6906 template-parameter TEMPL. */
6908 static tree
6910 tsubst_flags_t complain)
6911 {
6912 /* Consider an example where a template template parameter declared as
6914 template <class T, class U = std::allocator<T> > class TT
6916 The template parameter level of T and U are one level larger than
6917 of TT. To proper process the default argument of U, say when an
6918 instantiation `TT<int>' is seen, we need to build the full
6919 arguments containing {int} as the innermost level. Outer levels,
6920 available when not appearing as default template argument, can be
6921 obtained from the arguments of the enclosing template.
6923 Suppose that TT is later substituted with std::vector. The above
6924 instantiation is `TT<int, std::allocator<T> >' with TT at
6925 level 1, and T at level 2, while the template arguments at level 1
6926 becomes {std::vector} and the inner level 2 is {int}. */
6930 {
6932 /* We want arguments for the partial specialization, not arguments for
6933 the primary template. */
6935 else
6937 }
6939 {
6940 /* This is an argument of the current template, so we haven't set
6941 DECL_CONTEXT yet. */
6942 tree relevant_template_parms;
6944 /* Parameter levels that are greater than the level of the given
6945 template template parm are irrelevant. */
6952 }
6959 complain,
6962 }
6964 /* A cache of template template parameters with match-all default
6965 arguments. */
6967 static void
6969 {
6973 }
6974 static tree
6976 {
6981 }
6983 /* T is a bound template template-parameter. Copy its arguments into default
6984 arguments of the template template-parameter's template parameters. */
6986 static tree
6988 {
7011 {
7014 {
7017 }
7018 }
7022 }
7024 /* ARG is a bound potential template template-argument, and PARGS is a list
7025 of arguments for the corresponding template template-parameter. Adjust
7026 PARGS as appropriate for application to ARG's template, and if ARG is a
7027 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7028 arguments to the template template parameter. */
7030 static tree
7032 {
7036 {
7037 /* When comparing two template template-parameters in partial ordering,
7038 rewrite the one currently being used as an argument to have default
7039 arguments for all parameters. */
7045 }
7046 else
7047 {
7048 tree aparms
7053 }
7056 }
7058 /* Subroutine of unify for the case when PARM is a
7059 BOUND_TEMPLATE_TEMPLATE_PARM. */
7061 static int
7064 {
7068 /* The template template parm might be variadic and the argument
7069 not, so flatten both argument lists. */
7075 {
7076 /* In keeping with P0522R0, adjust P's template arguments
7077 to apply to A's template; then flatten it again. */
7080 }
7086 /* If the P0522 adjustment eliminated a pack expansion, deduce
7087 empty packs. */
7095 }
7097 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7098 template template parameters. Both PARM_PARMS and ARG_PARMS are
7099 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7100 or PARM_DECL.
7102 Consider the example:
7103 template <class T> class A;
7104 template<template <class U> class TT> class B;
7106 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7107 the parameters to A, and OUTER_ARGS contains A. */
7109 static int
7111 tree arg_parms,
7112 tsubst_flags_t complain,
7113 tree in_decl,
7114 tree outer_args)
7115 {
7127 {
7128 /* P0522R0: A template template-parameter P is at least as specialized as
7129 a template template-argument A if, given the following rewrite to two
7130 function templates, the function template corresponding to P is at
7131 least as specialized as the function template corresponding to A
7132 according to the partial ordering rules for function templates
7133 ([temp.func.order]). Given an invented class template X with the
7134 template parameter list of A (including default arguments):
7136 * Each of the two function templates has the same template parameters,
7137 respectively, as P or A.
7139 * Each function template has a single function parameter whose type is
7140 a specialization of X with template arguments corresponding to the
7141 template parameters from the respective function template where, for
7142 each template parameter PP in the template parameter list of the
7143 function template, a corresponding template argument AA is formed. If
7144 PP declares a parameter pack, then AA is the pack expansion
7145 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7147 If the rewrite produces an invalid type, then P is not at least as
7148 specialized as A. */
7150 /* So coerce P's args to apply to A's parms, and then deduce between A's
7151 args and the converted args. If that succeeds, A is at least as
7152 specialized as P, so they match.*/
7159 {
7165 }
7166 }
7168 /* Determine whether we have a parameter pack at the end of the
7169 template template parameter's template parameter list. */
7171 {
7178 {
7192 }
7193 }
7199 /* Check all of the template parameters except the parameter pack at
7200 the end (if any). */
7202 {
7211 outer_args))
7214 }
7217 {
7218 /* Check each of the template parameters in the template
7219 argument against the template parameter pack at the end of
7220 the template template parameter. */
7227 {
7234 outer_args))
7236 }
7237 }
7240 }
7242 /* Verifies that the deduced template arguments (in TARGS) for the
7243 template template parameters (in TPARMS) represent valid bindings,
7244 by comparing the template parameter list of each template argument
7245 to the template parameter list of its corresponding template
7246 template parameter, in accordance with DR150. This
7247 routine can only be called after all template arguments have been
7248 deduced. It will return TRUE if all of the template template
7249 parameter bindings are okay, FALSE otherwise. */
7250 bool
7252 {
7256 /* We're dealing with template parms in this process. */
7262 {
7267 {
7272 {
7273 /* Look inside the argument pack. */
7276 }
7279 {
7283 /* Extract the next argument from the argument
7284 pack. */
7288 /* Look at the pattern of the pack expansion. */
7291 /* Extract the template parameters from the template
7292 argument. */
7298 /* Verify that we can coerce the template template
7299 parameters from the template argument to the template
7300 parameter. This requires an exact match. */
7302 && !coerce_template_template_parms
7304 targ_parms,
7305 tf_none,
7306 tparm,
7307 targs))
7308 {
7311 }
7312 }
7313 }
7314 }
7316 out:
7320 }
7322 /* Since type attributes aren't mangled, we need to strip them from
7323 template type arguments. */
7325 static tree
7327 {
7337 }
7339 /* And from inside dependent non-type arguments like sizeof(Type). */
7341 static tree
7343 {
7353 }
7355 // A template declaration can be substituted for a constrained
7356 // template template parameter only when the argument is more
7357 // constrained than the parameter.
7358 static bool
7360 {
7363 /* For now, allow constrained template template arguments
7364 and unconstrained template template parameters. */
7370 // If the template parameter is constrained, we need to rewrite its
7371 // constraints in terms of the ARG's template parameters. This ensures
7372 // that all of the template parameter types will have the same depth.
7373 //
7374 // Note that this is only valid when coerce_template_template_parm is
7375 // true for the innermost template parameters of PARM and ARG. In other
7376 // words, because coercion is successful, this conversion will be valid.
7378 {
7385 }
7388 }
7390 // Convert a placeholder argument into a binding to the original
7391 // parameter. The original parameter is saved as the TREE_TYPE of
7392 // ARG.
7395 {
7398 }
7400 /* Convert the indicated template ARG as necessary to match the
7401 indicated template PARM. Returns the converted ARG, or
7402 error_mark_node if the conversion was unsuccessful. Error and
7403 warning messages are issued under control of COMPLAIN. This
7404 conversion is for the Ith parameter in the parameter list. ARGS is
7405 the full set of template arguments deduced so far. */
7407 static tree
7409 tree arg,
7410 tree args,
7411 tsubst_flags_t complain,
7413 tree in_decl)
7414 {
7415 tree orig_arg;
7416 tree val;
7422 /* Trivially convert placeholders. */
7431 {
7432 /* The template argument was the name of some
7433 member function. That's usually
7434 invalid, but static members are OK. In any
7435 case, grab the underlying fields/functions
7436 and issue an error later if required. */
7439 }
7447 /* When determining whether an argument pack expansion is a template,
7448 look at the pattern. */
7452 /* Deal with an injected-class-name used as a template template arg. */
7454 {
7457 {
7467 }
7468 }
7470 is_tmpl_type =
7486 {
7488 {
7492 }
7495 "to refer to a type member of a template parameter, "
7500 typename_type,
7501 complain);
7504 }
7506 {
7508 {
7510 {
7522 else
7525 }
7526 }
7528 }
7530 {
7532 {
7539 else
7542 }
7544 }
7547 {
7549 {
7553 /* The number of argument required is not known yet.
7554 Just accept it for now. */
7556 else
7557 {
7559 tree argparm;
7561 /* Strip alias templates that are equivalent to another
7562 template. */
7568 args))
7569 {
7572 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7573 TEMPLATE_DECL. */
7575 {
7580 }
7581 }
7582 else
7583 {
7585 {
7592 }
7595 }
7597 // Check that the constraints are compatible before allowing the
7598 // substitution.
7601 {
7603 {
7609 }
7611 }
7612 }
7613 }
7614 else
7616 /* We only form one instance of each template specialization.
7617 Therefore, if we use a non-canonical variant (i.e., a
7618 typedef), any future messages referring to the type will use
7619 the typedef, which is confusing if those future uses do not
7620 themselves also use the typedef. */
7623 }
7624 else
7625 {
7629 {
7631 /* There's nothing to check for an auto argument pack. */
7637 }
7638 else
7645 {
7648 else
7649 {
7650 /* Not sure if this is reachable, but it doesn't hurt
7651 to be robust. */
7654 }
7655 }
7658 /* We used to call digest_init here. However, digest_init
7659 will report errors, which we don't want when complain
7660 is zero. More importantly, digest_init will try too
7661 hard to convert things: for example, `0' should not be
7662 converted to pointer type at this point according to
7663 the standard. Accepting this is not merely an
7664 extension, since deciding whether or not these
7665 conversions can occur is part of determining which
7666 function template to call, or whether a given explicit
7667 argument specification is valid. */
7669 else
7679 {
7680 /* Reject template arguments that are references to built-in
7681 functions with no library fallbacks. */
7690 }
7693 {
7694 /* Strip typedefs from the SCOPE_REF. */
7697 complain);
7700 }
7701 }
7704 }
7706 /* Coerces the remaining template arguments in INNER_ARGS (from
7707 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7708 Returns the coerced argument pack. PARM_IDX is the position of this
7709 parameter in the template parameter list. ARGS is the original
7710 template argument list. */
7711 static tree
7714 tree args,
7715 tree inner_args,
7717 tree new_args,
7719 tree in_decl,
7720 tsubst_flags_t complain)
7721 {
7724 tree packed_args;
7725 tree argument_pack;
7732 {
7733 /* When the template parameter is a non-type template parameter pack
7734 or template template parameter pack whose type or template
7735 parameters use parameter packs, we know exactly how many arguments
7736 we are looking for. Build a vector of the instantiated decls for
7737 these template parameters in PACKED_PARMS. */
7738 /* We can't use make_pack_expansion here because it would interpret a
7739 _DECL as a use rather than a declaration. */
7753 /* If we're doing a partial instantiation of a member template,
7754 verify that all of the types used for the non-type
7755 template parameter pack are, in fact, valid for non-type
7756 template parameters. */
7759 {
7762 {
7766 }
7767 /* We don't know how many args we have yet, just
7768 use the unconverted ones for now. */
7770 }
7773 }
7774 /* Check if we have a placeholder pack, which indicates we're
7775 in the context of a introduction list. In that case we want
7776 to match this pack to the single placeholder. */
7780 {
7783 }
7784 else
7787 /* Convert the remaining arguments, which will be a part of the
7788 parameter pack "parm". */
7791 {
7797 {
7798 /* Once we've packed as many args as we have types, stop. */
7802 /* We don't know how many args we have yet, just
7803 use the unconverted ones for now. */
7805 else
7807 }
7810 {
7813 }
7814 else
7817 in_decl);
7821 }
7825 {
7830 }
7835 else
7836 {
7841 }
7848 }
7850 /* Returns the number of pack expansions in the template argument vector
7851 ARGS. */
7853 static int
7855 {
7860 {
7864 }
7866 }
7868 /* Convert all template arguments to their appropriate types, and
7869 return a vector containing the innermost resulting template
7870 arguments. If any error occurs, return error_mark_node. Error and
7871 warning messages are issued under control of COMPLAIN.
7873 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7874 for arguments not specified in ARGS. Otherwise, if
7875 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7876 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7877 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7878 ARGS. */
7880 static tree
7882 tree args,
7883 tree in_decl,
7884 tsubst_flags_t complain,
7887 {
7889 tree orig_inner_args;
7890 tree inner_args;
7891 tree new_args;
7892 tree new_inner_args;
7896 /* When used as a boolean value, indicates whether this is a
7897 variadic template parameter list. Since it's an int, we can also
7898 subtract it from nparms to get the number of non-variadic
7899 parameters. */
7904 /* Likewise for parameters with default arguments. */
7912 /* Determine if there are any parameter packs or default arguments. */
7914 {
7922 }
7925 /* If there are no parameters that follow a parameter pack, we need to
7926 expand any argument packs so that we can deduce a parameter pack from
7927 some non-packed args followed by an argument pack, as in variadic85.C.
7928 If there are such parameters, we need to leave argument packs intact
7929 so the arguments are assigned properly. This can happen when dealing
7930 with a nested class inside a partial specialization of a class
7931 template, as in variadic92.C, or when deducing a template parameter pack
7932 from a sub-declarator, as in variadic114.C. */
7936 /* Count any pack expansion args. */
7942 && require_all_args
7943 && !variadic_args_p
7944 && (!use_default_args
7947 {
7949 {
7951 {
7955 }
7956 else
7963 }
7966 }
7967 /* We can't pass a pack expansion to a non-pack parameter of an alias
7968 template (DR 1430). */
7972 && variadic_args_p
7974 {
7976 {
7978 {
7984 {
7987 "pack expansion argument for non-pack parameter "
7989 else
7991 "pack expansion argument for non-pack parameter "
7995 }
7996 }
7998 found:;
7999 }
8001 }
8003 /* We need to evaluate the template arguments, even though this
8004 template-id may be nested within a "sizeof". */
8013 {
8014 tree arg;
8015 tree parm;
8017 /* Get the Ith template parameter. */
8021 {
8024 }
8026 /* Calculate the next argument. */
8029 else
8034 {
8035 /* Some arguments will be placed in the
8036 template parameter pack PARM. */
8043 {
8044 /* We don't know how many args we have yet, just use the
8045 unconverted (and still packed) ones for now. */
8049 }
8053 /* Store this argument. */
8055 {
8056 lost++;
8057 /* We are done with all of the arguments. */
8059 }
8060 else
8061 {
8064 }
8067 }
8069 {
8071 {
8072 /* "If every valid specialization of a variadic template
8073 requires an empty template parameter pack, the template is
8074 ill-formed, no diagnostic required." So check that the
8075 pattern works with this parameter. */
8080 in_decl);
8082 {
8087 }
8089 /* Recover from missing typename. */
8093 /* We don't know how many args we have yet, just
8094 use the unconverted ones for now. */
8098 }
8099 }
8101 {
8102 /* There must be a default arg in this case. */
8105 /* The position of the first default template argument,
8106 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8107 Record that. */
8111 }
8112 else
8116 {
8119 }
8121 /* This only occurs if there was an error in the template
8122 parameter list itself (which we would already have
8123 reported) that we are trying to recover from, e.g., a class
8124 template with a parameter list such as
8125 template<typename..., typename>. */
8127 else
8133 lost++;
8135 }
8140 {
8142 {
8147 }
8149 }
8159 }
8161 /* Convert all template arguments to their appropriate types, and
8162 return a vector containing the innermost resulting template
8163 arguments. If any error occurs, return error_mark_node. Error and
8164 warning messages are not issued.
8166 Note that no function argument deduction is performed, and default
8167 arguments are used to fill in unspecified arguments. */
8168 tree
8170 {
8172 }
8174 /* Convert all template arguments to their appropriate type, and
8175 instantiate default arguments as needed. This returns a vector
8176 containing the innermost resulting template arguments, or
8177 error_mark_node if unsuccessful. */
8178 tree
8180 tsubst_flags_t complain)
8181 {
8183 }
8185 /* Like coerce_template_parms. If PARMS represents all template
8186 parameters levels, this function returns a vector of vectors
8187 representing all the resulting argument levels. Note that in this
8188 case, only the innermost arguments are coerced because the
8189 outermost ones are supposed to have been coerced already.
8191 Otherwise, if PARMS represents only (the innermost) vector of
8192 parameters, this function returns a vector containing just the
8193 innermost resulting arguments. */
8195 static tree
8197 tree args,
8198 tree in_decl,
8199 tsubst_flags_t complain,
8202 {
8205 tree coerced_args;
8208 {
8210 tree level;
8216 {
8217 tree l;
8221 require_all_args,
8222 use_default_args);
8223 else
8230 }
8231 }
8232 else
8235 require_all_args,
8236 use_default_args);
8238 }
8240 /* Returns 1 if template args OT and NT are equivalent. */
8242 int
8244 {
8253 /* For member templates */
8262 {
8279 }
8283 {
8286 /* Don't treat an alias template specialization with dependent
8287 arguments as equivalent to its underlying type when used as a
8288 template argument; we need them to be distinct so that we
8289 substitute into the specialization arguments at instantiation
8290 time. And aliases can't be equivalent without being ==, so
8291 we don't need to look any deeper.
8293 During partial ordering, however, we need to treat them normally so
8294 that we can order uses of the same alias with different
8295 cv-qualification (79960). */
8299 else
8301 }
8304 else
8305 {
8306 /* Try to treat a template non-type argument that has been converted
8307 to the parameter type as equivalent to one that hasn't yet. */
8320 }
8321 }
8323 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8324 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8325 NEWARG_PTR with the offending arguments if they are non-NULL. */
8327 int
8331 {
8344 {
8349 {
8355 }
8356 }
8358 }
8362 {
8364 }
8366 static void
8368 {
8378 /* We are called both from instantiate_decl, where we've already had a
8379 tinst_level pushed, and instantiate_template, where we haven't.
8380 Compensate. */
8391 else
8400 }
8403 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8404 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8405 documentation for TEMPLATE_ID_EXPR. */
8407 tree
8409 {
8410 tree type;
8418 {
8421 }
8424 {
8426 unknown_type_node,
8428 arglist);
8430 }
8437 }
8439 /* Within the scope of a template class S<T>, the name S gets bound
8440 (in build_self_reference) to a TYPE_DECL for the class, not a
8441 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8442 or one of its enclosing classes, and that type is a template,
8443 return the associated TEMPLATE_DECL. Otherwise, the original
8444 DECL is returned.
8446 Also handle the case when DECL is a TREE_LIST of ambiguous
8447 injected-class-names from different bases. */
8449 tree
8451 {
8455 /* DR 176: A lookup that finds an injected-class-name (10.2
8456 [class.member.lookup]) can result in an ambiguity in certain cases
8457 (for example, if it is found in more than one base class). If all of
8458 the injected-class-names that are found refer to specializations of
8459 the same class template, and if the name is followed by a
8460 template-argument-list, the reference refers to the class template
8461 itself and not a specialization thereof, and is not ambiguous. */
8463 {
8466 {
8472 }
8475 else
8477 }
8483 }
8485 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8486 parameters, find the desired type.
8488 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8490 IN_DECL, if non-NULL, is the template declaration we are trying to
8491 instantiate.
8493 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8494 the class we are looking up.
8496 Issue error and warning messages under control of COMPLAIN.
8498 If the template class is really a local class in a template
8499 function, then the FUNCTION_CONTEXT is the function in which it is
8500 being instantiated.
8502 ??? Note that this function is currently called *twice* for each
8503 template-id: the first time from the parser, while creating the
8504 incomplete type (finish_template_type), and the second type during the
8505 real instantiation (instantiate_template_class). This is surely something
8506 that we want to avoid. It also causes some problems with argument
8507 coercion (see convert_nontype_argument for more information on this). */
8509 static tree
8512 {
8514 tree t;
8517 spec_entry elt;
8518 hashval_t hash;
8521 {
8525 else
8526 {
8533 }
8536 }
8538 {
8541 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8542 an implicit typename for the second A. Deal with it. */
8547 {
8550 }
8551 }
8554 {
8557 }
8559 {
8563 }
8565 {
8568 }
8570 /* Issue an error message if we didn't find a template. */
8572 {
8576 }
8579 /* Make sure it's a user visible template, if it was named by
8580 the user. */
8583 {
8585 {
8589 }
8591 }
8595 /* An alias that just changes the name of a template is equivalent to the
8596 other template, so if any of the arguments are pack expansions, strip
8597 the alias to avoid problems with a pack expansion passed to a non-pack
8598 alias template parameter (DR 1430). */
8603 {
8604 tree parm;
8613 }
8614 else
8615 {
8617 tree gen_tmpl;
8618 tree type_decl;
8626 /* An error occurred while building the template TEMPL, and a
8627 diagnostic has most certainly been emitted for that
8628 already. Let's propagate that error. */
8637 {
8638 /* We've been given an incomplete set of template arguments.
8639 For example, given:
8641 template <class T> struct S1 {
8642 template <class U> struct S2 {};
8643 template <class U> struct S2<U*> {};
8644 };
8646 we will be called with an ARGLIST of `U*', but the
8647 TEMPLATE will be `template <class T> template
8648 <class U> struct S1<T>::S2'. We must fill in the missing
8649 arguments. */
8653 }
8655 /* Now we should have enough arguments. */
8658 /* From here on, we're only interested in the most general
8659 template. */
8661 /* Calculate the BOUND_ARGS. These will be the args that are
8662 actually tsubst'd into the definition to create the
8663 instantiation. */
8665 complain,
8670 /* We were unable to bind the arguments. */
8673 /* In the scope of a template class, explicit references to the
8674 template class refer to the type of the template, not any
8675 instantiation of it. For example, in:
8677 template <class T> class C { void f(C<T>); }
8679 the `C<T>' is just the same as `C'. Outside of the
8680 class, however, such a reference is an instantiation. */
8684 {
8689 }
8691 /* If we already have this specialization, return it. */
8701 /* If the the template's constraints are not satisfied,
8702 then we cannot form a valid type.
8704 Note that the check is deferred until after the hash
8705 lookup. This prevents redundant checks on previously
8706 instantiated specializations. */
8708 {
8710 {
8713 }
8715 }
8719 /* If the deduced arguments are invalid, then the binding
8720 failed. */
8724 complain))
8731 {
8736 }
8746 /* Create the type. */
8748 {
8749 /* The user referred to a specialization of an alias
8750 template represented by GEN_TMPL.
8752 [temp.alias]/2 says:
8754 When a template-id refers to the specialization of an
8755 alias template, it is equivalent to the associated
8756 type obtained by substitution of its
8757 template-arguments for the template-parameters in the
8758 type-id of the alias template. */
8761 /* Note that the call above (by indirectly calling
8762 register_specialization in tsubst_decl) registers the
8763 TYPE_DECL representing the specialization of the alias
8764 template. So next time someone substitutes ARGLIST for
8765 the template parms into the alias template (GEN_TMPL),
8766 she'll get that TYPE_DECL back. */
8770 }
8772 {
8774 {
8785 }
8786 else
8787 {
8788 /* We don't want to call start_enum for this type, since
8789 the values for the enumeration constants may involve
8790 template parameters. And, no one should be interested
8791 in the enumeration constants for such a type. */
8794 }
8798 }
8800 {
8806 /* A local class. Make sure the decl gets registered properly. */
8811 /* This instantiation is another name for the primary
8812 template type. Set the TYPE_CANONICAL field
8813 appropriately. */
8816 /* Some of the template arguments require structural
8817 equality testing, so this template class requires
8818 structural equality testing. */
8820 }
8821 else
8824 /* If we called start_enum or pushtag above, this information
8825 will already be set up. */
8827 {
8834 }
8835 else
8839 {
8845 {
8848 }
8849 }
8853 {
8857 {
8858 tree attributes
8866 }
8867 }
8869 /* Let's consider the explicit specialization of a member
8870 of a class template specialization that is implicitly instantiated,
8871 e.g.:
8872 template<class T>
8873 struct S
8874 {
8875 template<class U> struct M {}; //#0
8876 };
8878 template<>
8879 template<>
8880 struct S<int>::M<char> //#1
8881 {
8882 int i;
8883 };
8884 [temp.expl.spec]/4 says this is valid.
8886 In this case, when we write:
8887 S<int>::M<char> m;
8889 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8890 the one of #0.
8892 When we encounter #1, we want to store the partial instantiation
8893 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8895 For all cases other than this "explicit specialization of member of a
8896 class template", we just want to store the most general template into
8897 the CLASSTYPE_TI_TEMPLATE of M.
8899 This case of "explicit specialization of member of a class template"
8900 only happens when:
8901 1/ the enclosing class is an instantiation of, and therefore not
8902 the same as, the context of the most general template, and
8903 2/ we aren't looking at the partial instantiation itself, i.e.
8904 the innermost arguments are not the same as the innermost parms of
8905 the most general template.
8907 So it's only when 1/ and 2/ happens that we want to use the partial
8908 instantiation of the member template in lieu of its most general
8909 template. */
8913 /* the enclosing class must be an instantiation... */
8916 {
8920 tree partial_inst_args =
8927 use_partial_inst_tmpl =
8928 /*...and we must not be looking at the partial instantiation
8929 itself. */
8931 partial_inst_args);
8932 }
8935 /* This case is easy; there are no member templates involved. */
8937 else
8938 {
8939 /* This is a full instantiation of a member template. Find
8940 the partial instantiation of which this is an instance. */
8942 /* Temporarily reduce by one the number of levels in the ARGLIST
8943 so as to avoid comparing the last set of arguments. */
8947 /* FOUND is either a proper class type, or an alias
8948 template specialization. In the later case, it's a
8949 TYPE_DECL, resulting from the substituting of arguments
8950 for parameters in the TYPE_DECL of the alias template
8951 done earlier. So be careful while getting the template
8952 of FOUND. */
8954 ? found
8958 }
8960 // Build template info for the new specialization.
8969 /* Note this use of the partial instantiation so we can check it
8970 later in maybe_process_partial_specialization. */
8977 /* Now that the type has been registered on the instantiations
8978 list, we set up the enumerators. Because the enumeration
8979 constants may involve the enumeration type itself, we make
8980 sure to register the type first, and then create the
8981 constants. That way, doing tsubst_expr for the enumeration
8982 constants won't result in recursive calls here; we'll find
8983 the instantiation and exit above. */
8987 /* If the type makes use of template parameters, the
8988 code that generates debugging information will crash. */
8991 /* Possibly limit visibility based on template args. */
8998 }
8999 }
9001 /* Wrapper for lookup_template_class_1. */
9003 tree
9006 {
9007 tree ret;
9013 }
9015 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9017 tree
9019 {
9020 /* The type of the expression is NULL_TREE since the template-id could refer
9021 to an explicit or partial specialization. */
9024 /* Except that concepts are always bool. */
9027 }
9029 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9031 tree
9033 {
9037 /* We never want to return a VAR_DECL for a variable concept, since they
9038 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9053 {
9055 {
9058 }
9060 }
9062 /* If a template-id refers to a specialization of a variable
9063 concept, then the expression is true if and only if the
9064 concept's constraints are satisfied by the given template
9065 arguments.
9067 NOTE: This is an extension of Concepts Lite TS that
9068 allows constraints to be used in expressions. */
9070 {
9073 }
9076 }
9078 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9079 TARGS template args, and instantiate it if it's not dependent. */
9081 tree
9083 tsubst_flags_t complain)
9084 {
9087 {
9090 }
9093 }
9095 \f
9096 struct pair_fn_data
9097 {
9098 tree_fn_t fn;
9099 tree_fn_t any_fn;
9101 /* True when we should also visit template parameters that occur in
9102 non-deduced contexts. */
9105 };
9107 /* Called from for_each_template_parm via walk_tree. */
9109 static tree
9111 {
9118 #define WALK_SUBTREE(NODE) \
9119 do \
9120 { \
9121 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9122 pfd->include_nondeduced_p, \
9123 pfd->any_fn); \
9124 if (result) goto out; \
9125 } \
9126 while (0)
9136 {
9140 /* Fall through. */
9146 else
9156 /* Since we're not going to walk subtrees, we have to do this
9157 explicitly here. */
9159 /* Fall through. */
9162 /* Check the return type. */
9165 /* Check the parameter types. Since default arguments are not
9166 instantiated until they are needed, the TYPE_ARG_TYPES may
9167 contain expressions that involve template parameters. But,
9168 no-one should be looking at them yet. And, once they're
9169 instantiated, they don't contain template parameters, so
9170 there's no point in looking at them then, either. */
9171 {
9172 tree parm;
9177 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9178 want walk_tree walking into them itself. */
9180 }
9183 {
9187 }
9204 /* Fall through. */
9216 /* Record template parameters such as `T' inside `TT<T>'. */
9218 /* Fall through. */
9230 /* A template template parameter is encountered. */
9234 /* Already substituted template template parameter */
9239 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9240 partial instantiation. */
9252 /* If there's no type, then this thing must be some expression
9253 involving template parameters. */
9275 }
9277 #undef WALK_SUBTREE
9279 /* We didn't find any template parameters we liked. */
9280 out:
9282 }
9284 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9285 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9286 call FN with the parameter and the DATA.
9287 If FN returns nonzero, the iteration is terminated, and
9288 for_each_template_parm returns 1. Otherwise, the iteration
9289 continues. If FN never returns a nonzero value, the value
9290 returned by for_each_template_parm is 0. If FN is NULL, it is
9291 considered to be the function which always returns 1.
9293 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9294 parameters that occur in non-deduced contexts. When false, only
9295 visits those template parameters that can be deduced. */
9297 static tree
9301 tree_fn_t any_fn)
9302 {
9304 tree result;
9306 /* Set up. */
9312 /* Walk the tree. (Conceptually, we would like to walk without
9313 duplicates, but for_each_template_parm_r recursively calls
9314 for_each_template_parm, so we would need to reorganize a fair
9315 bit to use walk_tree_without_duplicates, so we keep our own
9316 visited list.) */
9319 else
9322 for_each_template_parm_r,
9326 /* Clean up. */
9328 {
9331 }
9334 }
9336 /* Returns true if T depends on any template parameter. */
9338 int
9340 {
9370 else
9371 {
9374 }
9379 }
9381 /* Returns true iff current_function_decl is an incompletely instantiated
9382 template. Useful instead of processing_template_decl because the latter
9383 is set to 0 during instantiate_non_dependent_expr. */
9385 bool
9387 {
9396 }
9398 /* Returns true if T depends on any template parameter with level LEVEL. */
9400 bool
9402 {
9405 }
9407 /* Returns true if the signature of DECL depends on any template parameter from
9408 its enclosing class. */
9410 bool
9412 {
9422 template_parm_outer_level,
9432 }
9434 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9435 ill-formed translation unit, i.e. a variable or function that isn't
9436 usable in a constant expression. */
9440 {
9444 }
9446 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9447 neglectable and instantiated from within an erroneous instantiation. */
9449 static bool
9451 {
9462 }
9470 /* We're starting to instantiate D; record the template instantiation context
9471 for diagnostics and to restore it later. */
9473 bool
9475 {
9477 }
9479 /* We're starting to instantiate D; record the template instantiation context
9480 at LOC for diagnostics and to restore it later. */
9482 bool
9484 {
9488 {
9489 /* Tell error.c not to try to instantiate any templates. */
9492 "template instantiation depth exceeds maximum of %d"
9494 max_tinst_depth);
9496 }
9498 /* If the current instantiation caused problems, don't let it instantiate
9499 anything else. Do allow deduction substitution and decls usable in
9500 constant expressions. */
9504 /* When not -quiet, dump template instantiations other than functions, since
9505 announce_function will take care of those. */
9524 }
9526 /* We're done instantiating this template; return to the instantiation
9527 context. */
9529 void
9531 {
9532 /* Restore the filename and line number stashed away when we started
9533 this instantiation. */
9537 }
9539 /* We're instantiating a deferred template; restore the template
9540 instantiation context in which the instantiation was requested, which
9541 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9543 static tree
9545 {
9557 }
9559 /* Returns the TINST_LEVEL which gives the original instantiation
9560 context. */
9564 {
9570 }
9572 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9573 vector of template arguments, as for tsubst.
9575 Returns an appropriate tsubst'd friend declaration. */
9577 static tree
9579 {
9580 tree new_friend;
9585 /* This was a friend declared with an explicit template
9586 argument list, e.g.:
9588 friend void f<>(T);
9590 to indicate that f was a template instantiation, not a new
9591 function declaration. Now, we have to figure out what
9592 instantiation of what template. */
9593 {
9595 tree new_args;
9596 tree tmpl;
9599 /* Friend functions are looked up in the containing namespace scope.
9600 We must enter that scope, to avoid finding member functions of the
9601 current class with same name. */
9616 tsk_none);
9618 }
9622 /* The NEW_FRIEND will look like an instantiation, to the
9623 compiler, but is not an instantiation from the point of view of
9624 the language. For example, we might have had:
9626 template <class T> struct S {
9627 template <class U> friend void f(T, U);
9628 };
9630 Then, in S<int>, template <class U> void f(int, U) is not an
9631 instantiation of anything. */
9637 {
9641 }
9643 /* The mangled name for the NEW_FRIEND is incorrect. The function
9644 is not a template instantiation and should not be mangled like
9645 one. Therefore, we forget the mangling here; we'll recompute it
9646 later if we need it. */
9648 {
9651 }
9654 {
9655 tree old_decl;
9656 tree new_friend_template_info;
9657 tree new_friend_result_template_info;
9658 tree ns;
9661 /* We must save some information from NEW_FRIEND before calling
9662 duplicate decls since that function will free NEW_FRIEND if
9663 possible. */
9665 new_friend_is_defn =
9670 {
9671 /* This declaration is a `primary' template. */
9674 new_friend_result_template_info
9676 }
9677 else
9680 /* Inside pushdecl_namespace_level, we will push into the
9681 current namespace. However, the friend function should go
9682 into the namespace of the template. */
9692 {
9693 /* This new friend declaration matched an existing
9694 declaration. For example, given:
9696 template <class T> void f(T);
9697 template <class U> class C {
9698 template <class T> friend void f(T) {}
9699 };
9701 the friend declaration actually provides the definition
9702 of `f', once C has been instantiated for some type. So,
9703 old_decl will be the out-of-class template declaration,
9704 while new_friend is the in-class definition.
9706 But, if `f' was called before this point, the
9707 instantiation of `f' will have DECL_TI_ARGS corresponding
9708 to `T' but not to `U', references to which might appear
9709 in the definition of `f'. Previously, the most general
9710 template for an instantiation of `f' was the out-of-class
9711 version; now it is the in-class version. Therefore, we
9712 run through all specialization of `f', adding to their
9713 DECL_TI_ARGS appropriately. In particular, they need a
9714 new set of outer arguments, corresponding to the
9715 arguments for this class instantiation.
9717 The same situation can arise with something like this:
9719 friend void f(int);
9720 template <class T> class C {
9721 friend void f(T) {}
9722 };
9724 when `C<int>' is instantiated. Now, `f(int)' is defined
9725 in the class. */
9728 /* On the other hand, if the in-class declaration does
9729 *not* provide a definition, then we don't want to alter
9730 existing definitions. We can just leave everything
9731 alone. */
9732 ;
9733 else
9734 {
9738 /* Overwrite whatever template info was there before, if
9739 any, with the new template information pertaining to
9740 the declaration. */
9744 {
9745 /* We should have called reregister_specialization in
9746 duplicate_decls. */
9751 /* Instantiate it if the global has already been used. */
9755 }
9756 else
9757 {
9758 tree t;
9760 /* Indicate that the old function template is a partial
9761 instantiation. */
9769 /* Reassign any specializations already in the hash table
9770 to the new more general template, and add the
9771 additional template args. */
9775 {
9777 spec_entry elt;
9789 register_specialization
9792 }
9794 }
9795 }
9797 /* The information from NEW_FRIEND has been merged into OLD_DECL
9798 by duplicate_decls. */
9800 }
9801 }
9802 else
9803 {
9807 /* In the code
9808 template <class T> class C {
9809 template <class U> friend void C1<U>::f (); // case 1
9810 friend void C2<T>::f (); // case 2
9811 };
9812 we only need to make sure CONTEXT is a complete type for
9813 case 2. To distinguish between the two cases, we note that
9814 CONTEXT of case 1 remains dependent type after tsubst while
9815 this isn't true for case 2. */
9825 {
9827 /* do_friend adds the TEMPLATE_DECL for any member friend
9828 template even if it isn't a member template, i.e.
9829 template <class T> friend A<T>::f();
9830 Look through it in that case. */
9834 /* Check to see that the declaration is really present, and,
9835 possibly obtain an improved declaration. */
9840 }
9841 }
9844 }
9846 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9847 template arguments, as for tsubst.
9849 Returns an appropriate tsubst'd friend type or error_mark_node on
9850 failure. */
9852 static tree
9854 {
9855 tree friend_type;
9856 tree tmpl;
9857 tree context;
9860 {
9863 }
9868 {
9871 else
9873 }
9875 /* Look for a class template declaration. We look for hidden names
9876 because two friend declarations of the same template are the
9877 same. For example, in:
9879 struct A {
9880 template <typename> friend class F;
9881 };
9882 template <typename> struct B {
9883 template <typename> friend class F;
9884 };
9886 both F templates are the same. */
9890 /* But, if we don't find one, it might be because we're in a
9891 situation like this:
9893 template <class T>
9894 struct S {
9895 template <class U>
9896 friend struct S;
9897 };
9899 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9900 for `S<int>', not the TEMPLATE_DECL. */
9902 {
9905 }
9908 {
9909 /* The friend template has already been declared. Just
9910 check to see that the declarations match, and install any new
9911 default parameters. We must tsubst the default parameters,
9912 of course. We only need the innermost template parameters
9913 because that is all that redeclare_class_template will look
9914 at. */
9917 {
9918 tree parms;
9919 location_t saved_input_location;
9929 }
9932 }
9933 else
9934 {
9935 /* The friend template has not already been declared. In this
9936 case, the instantiation of the template class will cause the
9937 injection of this template into the global scope. */
9942 /* The new TMPL is not an instantiation of anything, so we
9943 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9944 the new type because that is supposed to be the corresponding
9945 template decl, i.e., TMPL. */
9952 /* Inject this template into the global scope. */
9954 }
9957 {
9960 else
9962 }
9965 }
9967 /* Returns zero if TYPE cannot be completed later due to circularity.
9968 Otherwise returns one. */
9970 static int
9972 {
9982 else
9984 }
9989 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
9990 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
9992 static tree
9995 {
10004 {
10011 clauses
10015 else
10017 }
10018 /* If the first attribute argument is an identifier, don't
10019 pass it through tsubst. Attributes like mode, format,
10020 cleanup and several target specific attributes expect it
10021 unmodified. */
10023 {
10024 tree chain
10029 }
10031 {
10032 /* An attribute pack expansion. */
10041 {
10045 }
10047 }
10048 else
10055 }
10057 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10058 unchanged or a new TREE_LIST chain. */
10060 static tree
10063 {
10068 {
10072 }
10076 {
10079 {
10082 {
10084 do
10089 }
10090 }
10092 }
10095 }
10097 /* Apply any attributes which had to be deferred until instantiation
10098 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10099 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10101 static void
10104 {
10106 tree t;
10113 {
10117 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10118 to our attributes parameter. */
10120 }
10121 else
10122 {
10124 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10125 lookup_template_class_1, and should be preserved. */
10129 }
10133 {
10137 }
10141 {
10146 {
10149 {
10153 do
10156 }
10157 else
10159 }
10162 }
10163 }
10165 /* Perform (or defer) access check for typedefs that were referenced
10166 from within the template TMPL code.
10167 This is a subroutine of instantiate_decl and instantiate_class_template.
10168 TMPL is the template to consider and TARGS is the list of arguments of
10169 that template. */
10171 static void
10173 {
10174 location_t saved_location;
10185 {
10197 /* Make access check error messages point to the location
10198 of the use of the typedef. */
10202 tf_warning_or_error);
10203 }
10205 }
10207 static tree
10209 {
10211 tree typedecl;
10212 tree pbinfo;
10213 tree base_list;
10215 tree fn_context;
10224 /* Figure out which template is being instantiated. */
10228 /* Determine what specialization of the original template to
10229 instantiate. */
10232 {
10235 }
10237 {
10238 /* This TYPE is actually an instantiation of a partial
10239 specialization. We replace the innermost set of ARGS with
10240 the arguments appropriate for substitution. For example,
10241 given:
10243 template <class T> struct S {};
10244 template <class T> struct S<T*> {};
10246 and supposing that we are instantiating S<int*>, ARGS will
10247 presently be {int*} -- but we need {int}. */
10250 }
10251 else
10252 {
10255 }
10257 /* If the template we're instantiating is incomplete, then clearly
10258 there's nothing we can do. */
10262 /* If we've recursively instantiated too many templates, stop. */
10266 /* Now we're really doing the instantiation. Mark the type as in
10267 the process of being defined. */
10270 /* We may be in the middle of deferred access check. Disable
10271 it now. */
10278 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10283 else
10284 {
10287 }
10288 /* Use #pragma pack from the template context. */
10294 /* Set the input location to the most specialized template definition.
10295 This is needed if tsubsting causes an error. */
10307 {
10310 /* Adjust visibility for template arguments. */
10312 }
10318 /* We should never instantiate a nested class before its enclosing
10319 class; we need to look up the nested class by name before we can
10320 instantiate it, and that lookup should instantiate the enclosing
10321 class. */
10327 {
10328 tree pbase_binfo;
10329 tree pushed_scope;
10332 /* We must enter the scope containing the type, as that is where
10333 the accessibility of types named in dependent bases are
10334 looked up from. */
10337 /* Substitute into each of the bases to determine the actual
10338 basetypes. */
10340 {
10341 tree base;
10347 {
10348 expanded_bases =
10355 }
10358 {
10360 /* Extract the already-expanded base class. */
10362 else
10363 /* Substitute to figure out the base class. */
10365 NULL_TREE);
10373 }
10374 }
10376 /* The list is now in reverse order; correct that. */
10381 }
10382 /* Now call xref_basetypes to set up all the base-class
10383 information. */
10391 /* Now that our base classes are set up, enter the scope of the
10392 class, so that name lookups into base classes, etc. will work
10393 correctly. This is precisely analogous to what we do in
10394 begin_class_definition when defining an ordinary non-template
10395 class, except we also need to push the enclosing classes. */
10398 /* Now members are processed in the order of declaration. */
10401 {
10405 {
10407 {
10408 /* Build new CLASSTYPE_NESTED_UTDS. */
10410 tree newtag;
10416 /* If the member is a class template, then -- even after
10417 substitution -- there may be dependent types in the
10418 template argument list for the class. We increment
10419 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10420 that function will assume that no types are dependent
10421 when outside of a template. */
10431 {
10435 /* Unfortunately, lookup_template_class sets
10436 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10437 instantiation (i.e., for the type of a member
10438 template class nested within a template class.)
10439 This behavior is required for
10440 maybe_process_partial_specialization to work
10441 correctly, but is not accurate in this case;
10442 the TAG is not an instantiation of anything.
10443 (The corresponding TEMPLATE_DECL is an
10444 instantiation, but the TYPE is not.) */
10447 /* Now, we call pushtag to put this NEWTAG into the scope of
10448 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10449 pushtag calling push_template_decl. We don't have to do
10450 this for enums because it will already have been done in
10451 tsubst_enum. */
10455 }
10456 }
10458 {
10459 /* Build new TYPE_METHODS. */
10460 tree r;
10469 /* Instantiate members marked with attribute used. */
10475 }
10478 /* A closure type for a lambda in a default argument for a
10479 member template. Ignore it; it will be instantiated with
10481 else
10482 {
10483 /* Build new TYPE_FIELDS. */
10485 {
10486 tree condition;
10489 condition =
10499 }
10501 {
10502 tree r;
10506 /* The file and line for this declaration, to
10507 assist in error message reporting. Since we
10508 called push_tinst_level above, we don't need to
10509 restore these. */
10519 {
10520 /* A capture pack became multiple fields. */
10523 }
10526 {
10530 {
10531 /* In [temp.inst]:
10533 [t]he initialization (and any associated
10534 side-effects) of a static data member does
10535 not occur unless the static data member is
10536 itself used in a way that requires the
10537 definition of the static data member to
10538 exist.
10540 Therefore, we do not substitute into the
10541 initialized for the static data member here. */
10542 finish_static_data_member_decl
10548 /* Instantiate members marked with attribute used. */
10551 }
10553 {
10554 /* Determine whether R has a valid type and can be
10555 completed later. If R is invalid, then its type
10556 is replaced by error_mark_node. */
10562 {
10563 /* If R's type couldn't be completed and
10564 it isn't a flexible array member (whose
10565 type is incomplete by definition) give
10566 an error. */
10569 }
10570 }
10572 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10573 such a thing will already have been added to the field
10574 list by tsubst_enum in finish_member_declaration in the
10575 CLASSTYPE_NESTED_UTDS case above. */
10579 {
10582 }
10583 }
10584 }
10585 }
10586 }
10587 else
10588 {
10591 {
10592 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10598 {
10599 /* template <class T> friend class C; */
10602 }
10604 {
10605 /* template <class T> friend class C::D; */
10611 }
10614 {
10615 /* This could be either
10617 friend class T::C;
10619 when dependent_type_p is false or
10621 template <class U> friend class T::C;
10623 otherwise. */
10624 /* Bump processing_template_decl in case this is something like
10625 template <class T> friend struct A<T>::B. */
10632 }
10635 {
10636 /* friend class C;
10638 where C hasn't been declared yet. Let's lookup name
10639 from namespace scope directly, bypassing any name that
10640 come from dependent base class. */
10643 /* The call to xref_tag_from_type does injection for friend
10644 classes. */
10646 friend_type =
10650 }
10652 /* friend class C<T>; */
10655 /* Otherwise it's
10657 friend class C;
10659 where C is already declared or
10661 friend class C<int>;
10663 We don't have to do anything in these cases. */
10666 /* Trick make_friend_class into realizing that the friend
10667 we're adding is a template, not an ordinary class. It's
10668 important that we use make_friend_class since it will
10669 perform some error-checking and output cross-reference
10670 information. */
10678 }
10679 else
10680 {
10681 /* Build new DECL_FRIENDLIST. */
10682 tree r;
10684 /* The file and line for this declaration, to
10685 assist in error message reporting. Since we
10686 called push_tinst_level above, we don't need to
10687 restore these. */
10691 {
10694 }
10699 {
10702 }
10703 }
10704 }
10705 }
10708 {
10709 /* Restore these before substituting into the lambda capture
10710 initializers. */
10713 }
10716 {
10719 {
10725 {
10726 /* Set function_depth to avoid garbage collection. */
10730 }
10732 /* We need to instantiate the capture list from the template
10733 after we've instantiated the closure members, but before we
10734 consider adding the conversion op. Also keep any captures
10735 that may have been added during instantiation of the op(). */
10737 tree tmpl_cap
10746 }
10747 else
10749 }
10751 /* Set the file and line number information to whatever is given for
10752 the class itself. This puts error messages involving generated
10753 implicit functions at a predictable point, and the same point
10754 that would be used for non-template classes. */
10761 /* We don't instantiate default arguments for member functions. 14.7.1:
10763 The implicit instantiation of a class template specialization causes
10764 the implicit instantiation of the declarations, but not of the
10765 definitions or default arguments, of the class member functions,
10766 member classes, static data members and member templates.... */
10768 /* Some typedefs referenced from within the template code need to be access
10769 checked at template instantiation time, i.e now. These types were
10770 added to the template at parsing time. Let's get those and perform
10771 the access checks then. */
10781 /* The vtable for a template class can be emitted in any translation
10782 unit in which the class is instantiated. When there is no key
10783 method, however, finish_struct_1 will already have added TYPE to
10784 the keyed_classes list. */
10789 }
10791 /* Wrapper for instantiate_class_template_1. */
10793 tree
10795 {
10796 tree ret;
10801 }
10803 static tree
10805 {
10806 tree r;
10812 else
10813 {
10820 }
10822 }
10824 /* Given a function parameter pack TMPL_PARM and some function parameters
10825 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10826 and set *SPEC_P to point at the next point in the list. */
10828 tree
10830 {
10831 /* Collect all of the extra "packed" parameters into an
10832 argument pack. */
10833 tree parmvec;
10834 tree parmtypevec;
10845 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10850 {
10853 }
10855 /* Build the argument packs. */
10862 }
10864 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10865 NONTYPE_ARGUMENT_PACK. */
10867 static tree
10869 {
10871 }
10873 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10874 pack expansion with no extra args, 2 if it has extra args, or 0
10875 if it is not a pack expansion. */
10877 static int
10879 {
10885 /* A decl pack is itself an expansion. */
10892 }
10895 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10897 static tree
10899 {
10906 }
10908 /* This is a subroutine of tsubst_pack_expansion.
10910 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10911 mechanism to store the (non complete list of) arguments of the
10912 substitution and return a non substituted pack expansion, in order
10913 to wait for when we have enough arguments to really perform the
10914 substitution. */
10916 static bool
10920 {
10921 /* If one pack has an expansion and another pack has a normal
10922 argument or if one pack has an empty argument and an another
10923 one hasn't then tsubst_pack_expansion cannot perform the
10924 substitution and need to fall back on the
10925 PACK_EXPANSION_EXTRA mechanism. */
10933 {
10936 parm_pack;
10938 {
10943 /* We can't substitute a pack expansion with extra args into
10944 our pattern. */
10948 else
10950 }
10954 }
10956 }
10958 /* [temp.variadic]/6 says that:
10960 The instantiation of a pack expansion [...]
10961 produces a list E1,E2, ..., En, where N is the number of elements
10962 in the pack expansion parameters.
10964 This subroutine of tsubst_pack_expansion produces one of these Ei.
10966 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10967 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10968 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10969 INDEX is the index 'i' of the element Ei to produce. ARGS,
10970 COMPLAIN, and IN_DECL are the same parameters as for the
10971 tsubst_pack_expansion function.
10973 The function returns the resulting Ei upon successful completion,
10974 or error_mark_node.
10976 Note that this function possibly modifies the ARGS parameter, so
10977 it's the responsibility of the caller to restore it. */
10979 static tree
10981 tree parm_packs,
10983 tree args /* This parm gets
10985 tsubst_flags_t complain,
10986 tree in_decl)
10987 {
10988 tree t;
10991 /* For each parameter pack, change the substitution of the parameter
10992 pack to the ith argument in its argument pack, then expand the
10993 pattern. */
10995 {
11000 ith_elem_is_expansion |=
11003 /* Select the Ith argument from the pack. */
11006 {
11008 {
11013 }
11014 else
11016 }
11017 else
11018 {
11023 {
11025 /* Update the corresponding argument. */
11027 }
11028 else
11029 /* Re-use the ARGUMENT_PACK_SELECT. */
11031 }
11033 }
11035 /* Substitute into the PATTERN with the (possibly altered)
11036 arguments. */
11038 /* Expanding a fixed parameter pack from
11039 coerce_template_parameter_pack. */
11044 {
11047 else
11050 }
11054 else
11057 /* If the Ith argument pack element is a pack expansion, then
11058 the Ith element resulting from the substituting is going to
11059 be a pack expansion as well. */
11064 }
11066 /* When the unexpanded parameter pack in a fold expression expands to an empty
11067 sequence, the value of the expression is as follows; the program is
11068 ill-formed if the operator is not listed in this table.
11070 && true
11071 || false
11072 , void() */
11074 tree
11076 {
11080 {
11089 }
11095 }
11097 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11098 form an expression that combines the two terms using the
11099 operator of T. */
11101 static tree
11103 {
11107 // Handle compound assignment operators.
11112 {
11122 complain);
11123 }
11124 }
11126 /* Substitute ARGS into the pack of a fold expression T. */
11130 {
11132 }
11134 /* Substitute ARGS into the pack of a fold expression T. */
11138 {
11140 }
11142 /* Expand a PACK of arguments into a grouped as left fold.
11143 Given a pack containing elements A0, A1, ..., An and an
11144 operator @, this builds the expression:
11146 ((A0 @ A1) @ A2) ... @ An
11148 Note that PACK must not be empty.
11150 The operator is defined by the original fold expression T. */
11152 static tree
11154 {
11157 {
11160 }
11162 }
11164 /* Substitute into a unary left fold expression. */
11166 static tree
11168 tree in_decl)
11169 {
11174 {
11178 }
11181 else
11183 }
11185 /* Substitute into a binary left fold expression.
11187 Do ths by building a single (non-empty) vector of argumnts and
11188 building the expression from those elements. */
11190 static tree
11192 tree in_decl)
11193 {
11202 {
11207 }
11215 }
11217 /* Expand a PACK of arguments into a grouped as right fold.
11218 Given a pack containing elementns A0, A1, ..., and an
11219 operator @, this builds the expression:
11221 A0@ ... (An-2 @ (An-1 @ An))
11223 Note that PACK must not be empty.
11225 The operator is defined by the original fold expression T. */
11227 tree
11229 {
11230 // Build the expression.
11234 {
11237 }
11239 }
11241 /* Substitute into a unary right fold expression. */
11243 static tree
11245 tree in_decl)
11246 {
11251 {
11255 }
11258 else
11260 }
11262 /* Substitute into a binary right fold expression.
11264 Do ths by building a single (non-empty) vector of arguments and
11265 building the expression from those elements. */
11267 static tree
11269 tree in_decl)
11270 {
11279 {
11284 }
11293 }
11296 /* Substitute ARGS into T, which is an pack expansion
11297 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11298 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11299 (if only a partial substitution could be performed) or
11300 ERROR_MARK_NODE if there was an error. */
11301 tree
11303 tree in_decl)
11304 {
11305 tree pattern;
11309 tree result;
11317 /* Add in any args remembered from an earlier partial instantiation. */
11322 /* Determine the argument packs that will instantiate the parameter
11323 packs used in the expansion expression. While we're at it,
11324 compute the number of arguments to be expanded and make sure it
11325 is consistent. */
11328 {
11335 {
11339 else
11342 }
11344 {
11345 /* We know we have correct local_specializations if this
11346 expansion is at function scope, or if we're dealing with a
11347 local parameter in a requires expression; for the latter,
11348 tsubst_requires_expr set it up appropriately. */
11351 else
11352 /* We can't rely on local_specializations for a parameter
11353 name used later in a function declaration (such as in a
11354 late-specified return type). Even if it exists, it might
11355 have the wrong value for a recursive call. */
11359 {
11360 /* This parameter pack was used in an unevaluated context. Just
11361 make a dummy decl, since it's only used for its type. */
11364 /* Partial instantiation of the parm_pack, we can't build
11365 up an argument pack yet. */
11367 else
11369 }
11370 }
11373 else
11374 {
11380 }
11387 /* This can only happen if we forget to expand an argument
11388 pack somewhere else. Just return an error, silently. */
11389 {
11393 }
11396 {
11400 /* Don't bother trying to do a partial substitution with
11401 incomplete packs; we'll try again after deduction. */
11408 {
11414 pattern);
11415 else
11418 pattern);
11420 }
11422 /* Keep track of the parameter packs and their corresponding
11423 argument packs. */
11426 }
11427 else
11428 {
11429 /* We can't substitute for this parameter pack. We use a flag as
11430 well as the missing_level counter because function parameter
11431 packs don't have a level. */
11434 }
11435 }
11437 /* If the expansion is just T..., return the matching argument pack, unless
11438 we need to call convert_from_reference on all the elements. This is an
11439 important optimization; see c++/68422. */
11442 {
11444 /* Types need no adjustment, nor does sizeof..., and if we still have
11445 some pack expansion args we won't do anything yet. */
11450 /* Also optimize expression pack expansions if we can tell that the
11451 elements won't have reference type. */
11457 /* Otherwise use the normal path so we get convert_from_reference. */
11458 }
11460 /* We cannot expand this expansion expression, because we don't have
11461 all of the argument packs we need. */
11463 {
11464 /* We got some full packs, but we can't substitute them in until we
11465 have values for all the packs. So remember these until then. */
11470 }
11472 {
11473 /* There were no real arguments, we're just replacing a parameter
11474 pack with another version of itself. Substitute into the
11475 pattern and return a PACK_EXPANSION_*. The caller will need to
11476 deal with that. */
11480 else
11484 }
11489 {
11490 /* We're in a late-specified return type, so create our own local
11491 specializations map; the current map is either NULL or (in the
11492 case of recursive unification) might have bindings that we don't
11493 want to use or alter. */
11496 }
11498 /* For each argument in each argument pack, substitute into the
11499 pattern. */
11503 {
11505 i,
11507 in_decl);
11510 {
11513 }
11514 }
11516 /* Update ARGS to restore the substitution from parameter packs to
11517 their argument packs. */
11519 {
11525 else
11526 {
11534 /* Update the corresponding argument. */
11538 else
11540 }
11541 }
11544 {
11547 }
11549 /* If the dependent pack arguments were such that we end up with only a
11550 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11556 }
11558 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11559 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11560 parameter packs; all parms generated from a function parameter pack will
11561 have the same DECL_PARM_INDEX. */
11563 tree
11565 {
11567 tree patparm;
11570 {
11576 }
11577 else
11578 {
11583 }
11586 }
11588 /* Make an argument pack out of the TREE_VEC VEC. */
11590 static tree
11592 {
11593 tree pack;
11597 else
11598 {
11602 }
11605 }
11607 /* Return an exact copy of template args T that can be modified
11608 independently. */
11610 static tree
11612 {
11620 {
11625 }
11631 }
11633 /* Substitute ARGS into the vector or list of template arguments T. */
11635 static tree
11637 {
11649 {
11651 tree new_arg;
11656 {
11657 /* Substitute into an expansion expression. */
11661 /* Add to the expanded length adjustment the number of
11662 expanded arguments. We subtract one from this
11663 measurement, because the argument pack expression
11664 itself is already counted as 1 in
11665 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11666 the argument pack is empty. */
11668 }
11670 {
11671 /* Substitute into each of the arguments. */
11677 new_arg,
11687 else
11694 }
11695 }
11696 else
11705 }
11710 /* Make space for the expanded arguments coming from template
11711 argument packs. */
11713 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11714 arguments for a member template.
11715 In that case each TREE_VEC in ORIG_T represents a level of template
11716 arguments, and ORIG_T won't carry any non defaulted argument count.
11717 It will rather be the nested TREE_VECs that will carry one.
11718 In other words, ORIG_T carries a non defaulted argument count only
11719 if it doesn't contain any nested TREE_VEC. */
11721 {
11725 }
11727 {
11731 {
11734 /* Now expand the template argument pack "in place". */
11737 }
11738 else
11739 {
11741 out++;
11742 }
11743 }
11746 }
11748 /* Substitute ARGS into one level PARMS of template parameters. */
11750 static tree
11752 {
11759 {
11767 }
11770 }
11772 /* Return the result of substituting ARGS into the template parameters
11773 given by PARMS. If there are m levels of ARGS and m + n levels of
11774 PARMS, then the result will contain n levels of PARMS. For
11775 example, if PARMS is `template <class T> template <class U>
11776 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11777 result will be `template <int*, double, class V>'. */
11779 static tree
11781 {
11785 /* When substituting into a template, we must set
11786 PROCESSING_TEMPLATE_DECL as the template parameters may be
11787 dependent if they are based on one-another, and the dependency
11788 predicates are short-circuit outside of templates. */
11795 {
11802 }
11807 }
11809 /* Return the result of substituting ARGS into one template parameter
11810 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11811 parameter and which TREE_PURPOSE is the default argument of the
11812 template parameter. */
11814 static tree
11816 {
11837 }
11839 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11840 type T. If T is not an aggregate or enumeration type, it is
11841 handled as if by tsubst. IN_DECL is as for tsubst. If
11842 ENTERING_SCOPE is nonzero, T is the context for a template which
11843 we are presently tsubst'ing. Return the substituted value. */
11845 static tree
11847 tree args,
11848 tsubst_flags_t complain,
11849 tree in_decl,
11851 {
11856 {
11861 /* Fall through. */
11865 {
11866 tree argvec;
11867 tree context;
11868 tree r;
11872 /* In "sizeof(X<I>)" we need to evaluate "I". */
11878 /* First, determine the context for the type we are looking
11879 up. */
11882 {
11885 /* If context is a nested class inside a class template,
11886 it may still need to be instantiated (c++/33959). */
11888 }
11890 /* Then, figure out what arguments are appropriate for the
11891 type we are trying to find. For example, given:
11893 template <class T> struct S;
11894 template <class T, class U> void f(T, U) { S<U> su; }
11896 and supposing that we are instantiating f<int, double>,
11897 then our ARGS will be {int, double}, but, when looking up
11898 S we only want {double}. */
11903 else
11904 {
11908 }
11914 }
11915 else
11916 /* This is not a template type, so there's nothing to do. */
11921 }
11922 }
11924 /* Substitute into the default argument ARG (a default argument for
11925 FN), which has the indicated TYPE. */
11927 tree
11929 {
11934 /* This can happen in invalid code. */
11938 /* This default argument came from a template. Instantiate the
11939 default argument here, not in tsubst. In the case of
11940 something like:
11942 template <class T>
11943 struct S {
11944 static T t();
11945 void f(T = t());
11946 };
11948 we must be careful to do name lookup in the scope of S<T>,
11949 rather than in the current class. */
11951 /* The "this" pointer is not valid in a default argument. */
11953 {
11958 }
11961 /* The default argument expression may cause implicitly defined
11962 member functions to be synthesized, which will result in garbage
11963 collection. We must treat this situation as if we were within
11964 the body of function so as to avoid collecting live data on the
11965 stack. */
11973 /* Restore the "this" pointer. */
11975 {
11978 }
11985 /* Make sure the default argument is reasonable. */
11991 }
11993 /* Substitute into all the default arguments for FN. */
11995 static void
11997 {
11998 tree arg;
11999 tree tmpl_args;
12003 /* If this function is not yet instantiated, we certainly don't need
12004 its default arguments. */
12007 /* Don't do this again for clones. */
12012 arg;
12018 complain);
12019 }
12021 /* Substitute the ARGS into the T, which is a _DECL. Return the
12022 result of the substitution. Issue error and warning messages under
12023 control of COMPLAIN. */
12025 static tree
12027 {
12028 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12029 location_t saved_loc;
12034 /* Set the filename and linenumber to improve error-reporting. */
12039 {
12041 {
12042 /* We can get here when processing a member function template,
12043 member class template, or template template parameter. */
12045 tree spec;
12046 tree tmpl_args;
12047 tree full_args;
12050 {
12051 /* Template template parameter is treated here. */
12055 /* If we get a real template back, return it. This can happen in
12056 the context of most_specialized_partial_spec. */
12059 else
12060 /* The new TEMPLATE_DECL was built in
12061 reduce_template_parm_level. */
12064 }
12066 /* We might already have an instance of this template.
12067 The ARGS are for the surrounding class type, so the
12068 full args contain the tsubst'd args for the context,
12069 plus the innermost args from the template decl. */
12073 /* Because this is a template, the arguments will still be
12074 dependent, even after substitution. If
12075 PROCESSING_TEMPLATE_DECL is not set, the dependency
12076 predicates will short-circuit. */
12084 /* If this is a default template template argument,
12085 tsubst might not have changed anything. */
12092 {
12095 }
12097 /* Make a new template decl. It will be similar to the
12098 original, but will record the current template arguments.
12099 We also create a new function declaration, which is just
12100 like the old one, but points to this new template, rather
12101 than the old one. */
12106 // Build new template info linking to the original template decl.
12111 {
12112 tree new_type;
12120 /* For a partial specialization, we need to keep pointing to
12121 the primary template. */
12127 }
12128 else
12129 {
12130 tree new_decl;
12142 }
12148 /* The template parameters for this new template are all the
12149 template parameters for the old template, except the
12150 outermost level of parameters. */
12153 complain);
12159 /* Record this non-type partial instantiation. */
12163 }
12167 {
12168 tree ctx;
12171 tree gen_tmpl;
12172 tree type;
12177 /* Nobody should be tsubst'ing into non-template functions. */
12181 {
12182 tree spec;
12184 /* If T is not dependent, just return it. */
12188 /* Calculate the most general template of which R is a
12189 specialization, and the complete set of arguments used to
12190 specialize R. */
12193 (DECL_TEMPLATE_RESULT
12199 /* Check to see if we already have this specialization. */
12204 {
12207 }
12209 /* We can see more levels of arguments than parameters if
12210 there was a specialization of a member template, like
12211 this:
12213 template <class T> struct S { template <class U> void f(); }
12214 template <> template <class U> void S<int>::f(U);
12216 Here, we'll be substituting into the specialization,
12217 because that's where we can find the code we actually
12218 want to generate, but we'll have enough arguments for
12219 the most general template.
12221 We also deal with the peculiar case:
12223 template <class T> struct S {
12224 template <class U> friend void f();
12225 };
12226 template <class U> void f() {}
12227 template S<int>;
12228 template void f<double>();
12230 Here, the ARGS for the instantiation of will be {int,
12231 double}. But, we only need as many ARGS as there are
12232 levels of template parameters in CODE_PATTERN. We are
12233 careful not to get fooled into reducing the ARGS in
12234 situations like:
12236 template <class T> struct S { template <class U> void f(U); }
12237 template <class T> template <> void S<T>::f(int) {}
12239 which we can spot because the pattern will be a
12240 specialization in this case. */
12242 parms_depth =
12247 }
12248 else
12249 {
12250 /* This special case arises when we have something like this:
12252 template <class T> struct S {
12253 friend void f<int>(int, double);
12254 };
12256 Here, the DECL_TI_TEMPLATE for the friend declaration
12257 will be an IDENTIFIER_NODE. We are being called from
12258 tsubst_friend_function, and we want only to create a
12259 new decl (R) with appropriate types so that we can call
12260 determine_specialization. */
12262 }
12265 {
12268 else
12272 }
12273 else
12274 {
12277 }
12282 /* If we hit excessive deduction depth, the type is bogus even if
12283 it isn't error_mark_node, so don't build a decl. */
12287 /* We do NOT check for matching decls pushed separately at this
12288 point, as they may not represent instantiations of this
12289 template, and in any case are considered separate under the
12290 discrete model. */
12294 /* Clear out the mangled name and RTL for the instantiation. */
12297 /* Leave DECL_INITIAL set on deleted instantiations. */
12302 /* OpenMP UDRs have the only argument a reference to the declared
12303 type. We want to diagnose if the declared type is a reference,
12304 which is invalid, but as references to references are usually
12305 quietly merged, diagnose it here. */
12307 {
12308 tree argtype
12313 "reference type %qT in "
12317 argtype);
12318 }
12321 /* Type-conversion operator. Reconstruct the name, in
12322 case it's the name of one of the template's parameters. */
12332 /* If this is an instantiation of a function with internal
12333 linkage, we already know what object file linkage will be
12334 assigned to the instantiation. */
12343 /* We'll re-clone as appropriate in instantiate_template. */
12346 /* If we aren't complaining now, return on error before we register
12347 the specialization so that we'll complain eventually. */
12353 /* When instantiating a constrained member, substitute
12354 into the constraints to create a new constraint. */
12357 {
12360 }
12362 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12363 this in the special friend case mentioned above where
12364 GEN_TMPL is NULL. */
12366 {
12371 tree new_r
12374 /* We instantiated this while substituting into
12375 the type earlier (template/friend54.C). */
12378 /* We're not supposed to instantiate default arguments
12379 until they are called, for a template. But, for a
12380 declaration like:
12382 template <class T> void f ()
12383 { extern void g(int i = T()); }
12385 we should do the substitution when the template is
12386 instantiated. We handle the member function case in
12387 instantiate_class_template since the default arguments
12388 might refer to other members of the class. */
12393 }
12394 else
12397 /* Copy the list of befriending classes. */
12401 {
12405 in_decl);
12406 }
12409 {
12413 /* If this is an instantiation of a member template, clone it.
12414 If it isn't, that'll be handled by
12415 clone_constructors_and_destructors. */
12418 }
12429 /* Possibly limit visibility based on template args. */
12432 {
12436 }
12444 }
12448 {
12456 {
12457 /* If there is a local specialization that isn't a
12458 parameter pack, it means that we're doing a "simple"
12459 substitution from inside tsubst_pack_expansion. Just
12460 return the local specialization (which will be a single
12461 parm). */
12468 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12469 the parameters in this function parameter pack. */
12473 {
12476 /* Zero-length parameter packs are boring. Just substitute
12477 into the chain. */
12481 }
12482 else
12483 {
12484 /* All we did was update the type. Make a note of that. */
12487 }
12488 }
12490 /* Loop through all of the parameters we'll build. When T is
12491 a function parameter pack, LEN is the number of expanded
12492 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12495 {
12502 /* We're on the Ith parameter of the function parameter
12503 pack. */
12504 {
12505 /* Get the Ith type. */
12508 /* Rename the parameter to include the index. */
12511 }
12513 /* We're dealing with a normal parameter. */
12521 {
12524 else
12527 }
12537 /* Keep track of the first new parameter we
12538 generate. That's what will be returned to the
12539 caller. */
12543 /* Build a proper chain of parameters when substituting
12544 into a function parameter pack. */
12547 }
12549 /* If cp_unevaluated_operand is set, we're just looking for a
12550 single dummy parameter, so don't keep going. */
12555 /* FIRST_R contains the start of the chain we've built. */
12557 }
12561 {
12568 {
12569 /* This field is a lambda capture pack. Return a TREE_VEC of
12570 the expanded fields to instantiate_class_template_1 and
12571 store them in the specializations hash table as a
12572 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12576 {
12579 }
12580 else
12581 {
12582 /* All we did was update the type. Make a note of that. */
12585 }
12586 }
12589 {
12592 {
12596 }
12606 /* For bit-fields, DECL_INITIAL gives the number of bits. For
12607 non-bit-fields DECL_INITIAL is a non-static data member
12608 initializer, which gets deferred instantiation. */
12614 {
12615 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12616 NSDMI in perform_member_init. Still set DECL_INITIAL
12617 so that we know there is one. */
12622 }
12623 /* We don't have to set DECL_CONTEXT here; it is set by
12624 finish_member_declaration. */
12632 }
12635 {
12643 }
12644 }
12648 /* We reach here only for member using decls. We also need to check
12649 uses_template_parms because DECL_DEPENDENT_P is not set for a
12650 using-declaration that designates a member of the current
12651 instantiation (c++/53549). */
12654 {
12658 {
12663 {
12667 {
12670 }
12671 else
12672 {
12675 }
12677 }
12678 }
12679 else
12680 {
12686 else
12687 {
12690 }
12691 }
12692 }
12693 else
12694 {
12697 }
12702 {
12705 tree spec;
12707 tree ctx;
12716 {
12717 /* If this is the canonical decl, we don't have to
12718 mess with instantiations, and often we can't (for
12719 typename, template type parms and such). Note that
12720 TYPE_NAME is not correct for the above test if
12721 we've copied the type for a typedef. */
12727 }
12729 /* Check to see if we already have the specialization we
12730 need. */
12733 {
12734 /* T is a static data member or namespace-scope entity.
12735 We have to substitute into namespace-scope variables
12736 (not just variable templates) because of cases like:
12738 template <class T> void f() { extern T t; }
12740 where the entity referenced is not known until
12741 instantiation time. */
12745 {
12747 complain,
12749 /* If CTX is unchanged, then T is in fact the
12750 specialization we want. That situation occurs when
12751 referencing a static data member within in its own
12752 class. We can use pointer equality, rather than
12753 same_type_p, because DECL_CONTEXT is always
12754 canonical... */
12756 /* ... unless T is a member template; in which
12757 case our caller can be willing to create a
12758 specialization of that template represented
12759 by T. */
12763 }
12766 {
12771 argvec = (coerce_innermost_template_parms
12779 }
12780 }
12781 else
12782 {
12783 /* A local variable. */
12785 /* Subsequent calls to pushdecl will fill this in. */
12787 /* Unless this is a reference to a static variable from an
12788 enclosing function, in which case we need to fill it in now. */
12790 {
12794 }
12796 }
12797 /* If we already have the specialization we need, there is
12798 nothing more to do. */
12800 {
12803 }
12805 /* Create a new node for the specialization we need. */
12808 {
12811 else
12818 }
12820 {
12821 /* Even if the original location is out of scope, the
12822 newly substituted one is not. */
12829 {
12830 /* It may seem that this case cannot occur, since:
12832 typedef void f();
12833 void g() { f x; }
12835 declares a function, not a variable. However:
12837 typedef void f();
12838 template <typename T> void g() { T t; }
12839 template void g<f>();
12841 is an attempt to declare a variable with function
12842 type. */
12844 /* R is not yet sufficiently initialized, so we
12845 just use its name. */
12848 }
12850 /* Wait until cp_finish_decl to set this again, to handle
12851 circular dependency (template/instantiate6.C). */
12856 {
12861 {
12864 }
12866 }
12870 }
12876 /* Clear out the mangled name and RTL for the instantiation. */
12880 /* The initializer must not be expanded until it is required;
12881 see [temp.inst]. */
12889 {
12890 /* Possibly limit visibility based on template args. */
12893 {
12897 }
12899 }
12902 {
12903 /* A static data member declaration is always marked
12904 external when it is declared in-class, even if an
12905 initializer is present. We mimic the non-template
12906 processing here. */
12914 }
12915 else
12916 {
12921 }
12929 /* Preserve a typedef that names a type. */
12931 {
12935 /* An alias template specialization can be dependent
12936 even if its underlying type is not. */
12938 }
12941 }
12946 }
12947 #undef RETURN
12949 out:
12950 /* Restore the file and line information. */
12954 }
12956 /* Substitute into the ARG_TYPES of a function type.
12957 If END is a TREE_CHAIN, leave it and any following types
12958 un-substituted. */
12960 static tree
12962 tree args,
12963 tree end,
12964 tsubst_flags_t complain,
12965 tree in_decl)
12966 {
12967 tree remaining_arg_types;
12971 tree default_arg;
12982 {
12983 /* For a pack expansion, perform substitution on the
12984 entire expression. Later on, we'll handle the arguments
12985 one-by-one. */
12990 /* So that we'll spin through the parameters, one by one. */
12992 else
12993 {
12994 /* We only partially substituted into the parameter
12995 pack. Our type is TYPE_PACK_EXPANSION. */
12998 }
12999 }
13012 {
13014 {
13018 }
13020 }
13021 /* DR 657. */
13025 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13026 top-level qualifiers as required. */
13029 /* We do not substitute into default arguments here. The standard
13030 mandates that they be instantiated only when needed, which is
13031 done in build_over_call. */
13035 {
13036 /* We've instantiated a template before its default arguments
13037 have been parsed. This can happen for a nested template
13038 class, and is not an error unless we require the default
13039 argument in a call of this function. */
13040 remaining_arg_types =
13043 }
13044 else
13045 remaining_arg_types =
13047 }
13050 }
13052 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13053 *not* handle the exception-specification for FNTYPE, because the
13054 initial substitution of explicitly provided template parameters
13055 during argument deduction forbids substitution into the
13056 exception-specification:
13058 [temp.deduct]
13060 All references in the function type of the function template to the
13061 corresponding template parameters are replaced by the specified tem-
13062 plate argument values. If a substitution in a template parameter or
13063 in the function type of the function template results in an invalid
13064 type, type deduction fails. [Note: The equivalent substitution in
13065 exception specifications is done only when the function is instanti-
13066 ated, at which point a program is ill-formed if the substitution
13067 results in an invalid type.] */
13069 static tree
13071 tree args,
13072 tsubst_flags_t complain,
13073 tree in_decl)
13074 {
13075 tree return_type;
13077 tree fntype;
13079 /* The TYPE_CONTEXT is not used for function/method types. */
13082 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13083 failure. */
13087 {
13088 /* Substitute the argument types. */
13100 {
13101 /* DR 1207: 'this' is in scope in the trailing return type. */
13103 }
13105 /* Substitute the return type. */
13109 {
13112 }
13113 }
13114 else
13115 /* Substitute the return type. */
13120 /* DR 486 clarifies that creation of a function type with an
13121 invalid return type is a deduction failure. */
13124 {
13126 {
13129 else
13131 }
13133 }
13134 /* And DR 657. */
13139 {
13140 /* Substitute the argument types. */
13145 }
13147 /* Construct a new type node and return it. */
13149 {
13154 }
13155 else
13156 {
13158 /* Don't pick up extra function qualifiers from the basetype. */
13161 {
13162 /* [temp.deduct]
13164 Type deduction may fail for any of the following
13165 reasons:
13167 -- Attempting to create "pointer to member of T" when T
13168 is not a class type. */
13171 r);
13173 }
13178 }
13185 }
13187 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13188 ARGS into that specification, and return the substituted
13189 specification. If there is no specification, return NULL_TREE. */
13191 static tree
13193 tree args,
13194 tsubst_flags_t complain,
13195 tree in_decl,
13197 {
13198 tree specs;
13199 tree new_specs;
13204 {
13205 /* A noexcept-specifier. */
13210 {
13211 /* Defer instantiation of noexcept-specifiers to avoid
13212 excessive instantiations (c++/49107). */
13215 {
13216 /* We already partially instantiated this member template,
13217 so combine the new args with the old. */
13222 }
13223 else
13224 {
13227 }
13228 }
13229 else
13230 new_specs = tsubst_copy_and_build
13234 }
13236 {
13239 else
13241 {
13242 tree spec;
13247 {
13248 /* Expand the pack expansion type. */
13251 in_decl);
13257 else
13258 {
13259 /* We're substituting into a member template, so
13260 we got a TYPE_PACK_EXPANSION back. Add that
13261 expansion and move on. */
13265 expanded_specs,
13266 complain);
13269 }
13270 }
13273 {
13276 else
13281 complain);
13282 }
13285 }
13286 }
13288 }
13290 /* Take the tree structure T and replace template parameters used
13291 therein with the argument vector ARGS. IN_DECL is an associated
13292 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13293 Issue error and warning messages under control of COMPLAIN. Note
13294 that we must be relatively non-tolerant of extensions here, in
13295 order to preserve conformance; if we allow substitutions that
13296 should not be allowed, we may allow argument deductions that should
13297 not succeed, and therefore report ambiguous overload situations
13298 where there are none. In theory, we could allow the substitution,
13299 but indicate that it should have failed, and allow our caller to
13300 make sure that the right thing happens, but we don't try to do this
13301 yet.
13303 This function is used for dealing with types, decls and the like;
13304 for expressions, use tsubst_expr or tsubst_copy. */
13306 tree
13308 {
13331 else
13336 /* Reuse typedefs. We need to do this to handle dependent attributes,
13337 such as attribute aligned. */
13340 {
13344 {
13345 /* DECL represents an alias template and we want to
13346 instantiate it. */
13350 }
13354 {
13358 }
13363 else
13364 /* The typedef is from a non-template context. */
13368 {
13370 r = cp_build_qualified_type_real
13374 }
13375 else
13376 {
13377 /* We don't have an instantiation yet, so drop the typedef. */
13382 }
13383 }
13400 {
13426 {
13432 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13433 needed. */
13439 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13440 with TREE_SIDE_EFFECTS that indicates this is not an integral
13441 constant expression. */
13444 {
13447 }
13450 }
13456 {
13462 /* Early in template argument deduction substitution, we don't
13463 want to reduce the level of 'auto', or it will be confused
13464 with a normal template parm in subsequent deduction. */
13476 {
13480 {
13481 /* See through ARGUMENT_PACK_SELECT arguments. */
13483 /* If the selected argument is an expansion E, that most
13484 likely means we were called from
13485 gen_elem_of_pack_expansion_instantiation during the
13486 substituting of pack an argument pack (which Ith
13487 element is a pack expansion, where I is
13488 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13489 In this case, the Ith element resulting from this
13490 substituting is going to be a pack expansion, which
13491 pattern is the pattern of E. Let's return the
13492 pattern of E, and
13493 gen_elem_of_pack_expansion_instantiation will
13494 build the resulting pack expansion from it. */
13496 {
13497 /* Make sure we aren't throwing away arg info. */
13500 }
13501 }
13502 }
13507 {
13509 /* If ARG is an argument pack, we don't actually want to
13510 perform a substitution here, because substitutions
13511 for argument packs are only done
13512 element-by-element. We can get to this point when
13513 substituting the type of a non-type template
13514 parameter pack, when that type actually contains
13515 template parameter packs from an outer template, e.g.,
13517 template<typename... Types> struct A {
13518 template<Types... Values> struct B { };
13519 }; */
13523 {
13529 return cp_build_qualified_type_real
13531 }
13533 {
13534 /* We are processing a type constructed from a
13535 template template parameter. */
13546 /* Consider this code:
13548 template <template <class> class Template>
13549 struct Internal {
13550 template <class Arg> using Bind = Template<Arg>;
13551 };
13553 template <template <class> class Template, class Arg>
13554 using Instantiate = Template<Arg>; //#0
13556 template <template <class> class Template,
13557 class Argument>
13558 using Bind =
13559 Instantiate<Internal<Template>::template Bind,
13560 Argument>; //#1
13562 When #1 is parsed, the
13563 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13564 parameter `Template' in #0 matches the
13565 UNBOUND_CLASS_TEMPLATE representing the argument
13566 `Internal<Template>::template Bind'; We then want
13567 to assemble the type `Bind<Argument>' that can't
13568 be fully created right now, because
13569 `Internal<Template>' not being complete, the Bind
13570 template cannot be looked up in that context. So
13571 we need to "store" `Bind<Argument>' for later
13572 when the context of Bind becomes complete. Let's
13573 store that in a TYPENAME_TYPE. */
13577 argvec),
13578 typename_type,
13579 complain);
13581 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13582 are resolving nested-types in the signature of a
13583 member function templates. Otherwise ARG is a
13584 TEMPLATE_DECL and is the real template to be
13585 instantiated. */
13593 complain);
13594 return cp_build_qualified_type_real
13596 }
13599 else
13600 /* TEMPLATE_PARM_INDEX. */
13602 }
13605 /* This can happen during the attempted tsubst'ing in
13606 unify. This means that we don't yet have any information
13607 about the template parameter in question. */
13610 /* If we get here, we must have been looking at a parm for a
13611 more deeply nested template. Make a new version of this
13612 template parameter, but with a lower level. */
13614 {
13619 {
13621 r = cp_build_qualified_type_real
13625 }
13632 /* Break infinite recursion when substituting the constraints
13634 else
13635 {
13646 {
13647 /* Propagate constraints on placeholders. */
13652 {
13656 }
13657 }
13660 /* We have reduced the level of the template
13661 template parameter, but not the levels of its
13662 template parameters, so canonical_type_parameter
13663 will not be able to find the canonical template
13664 template parameter for this level. Thus, we
13665 require structural equality checking to compare
13666 TEMPLATE_TEMPLATE_PARMs. */
13670 else
13674 {
13676 /* We might need to substitute into the types of non-type
13677 template parameters. */
13689 }
13690 }
13694 /* OK, now substitute the type of the non-type parameter. We
13695 couldn't do it earlier because it might be an auto parameter,
13696 and we wouldn't need to if we had an argument. */
13703 }
13706 }
13709 {
13717 {
13721 }
13724 {
13728 }
13731 {
13735 }
13741 }
13744 /* We should never be tsubsting a binfo. */
13748 /* A vector of template arguments. */
13754 {
13758 /* [temp.deduct]
13760 Type deduction may fail for any of the following
13761 reasons:
13763 -- Attempting to create a pointer to reference type.
13764 -- Attempting to create a reference to a reference type or
13765 a reference to void.
13767 Core issue 106 says that creating a reference to a reference
13768 during instantiation is no longer a cause for failure. We
13769 only enforce this check in strict C++98 mode. */
13773 {
13776 /* We keep track of the last time we issued this error
13777 message to avoid spewing a ton of messages during a
13778 single bad template instantiation. */
13781 {
13786 else
13789 }
13792 }
13796 {
13798 {
13801 type);
13802 else
13804 type);
13805 }
13807 }
13809 {
13813 }
13815 /* In C++0x, during template argument substitution, when there is an
13816 attempt to create a reference to a reference type, reference
13817 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13819 "If a template-argument for a template-parameter T names a type
13820 that is a reference to a type A, an attempt to create the type
13821 'lvalue reference to cv T' creates the type 'lvalue reference to
13822 A,' while an attempt to create the type type rvalue reference to
13823 cv T' creates the type T"
13824 */
13825 r = cp_build_reference_type
13828 else
13833 /* Will this ever be needed for TYPE_..._TO values? */
13837 }
13839 {
13842 {
13843 /* [temp.deduct]
13845 Type deduction may fail for any of the following
13846 reasons:
13848 -- Attempting to create "pointer to member of T" when T
13849 is not a class type. */
13853 }
13855 {
13859 }
13861 {
13865 }
13868 {
13869 /* The type of the implicit object parameter gets its
13870 cv-qualifiers from the FUNCTION_TYPE. */
13871 tree memptr;
13872 tree method_type
13877 complain);
13878 }
13879 else
13882 complain);
13883 }
13886 {
13887 tree fntype;
13888 tree specs;
13893 /* Substitute the exception specification. */
13901 }
13903 {
13908 /* As an optimization, we avoid regenerating the array type if
13909 it will obviously be the same as T. */
13913 /* These checks should match the ones in create_array_type_for_decl.
13915 [temp.deduct]
13917 The deduction may fail for any of the following reasons:
13919 -- Attempting to create an array with an element type that
13920 is void, a function type, or a reference type, or [DR337]
13921 an abstract class type. */
13927 {
13931 }
13939 {
13942 }
13945 }
13948 {
13960 {
13964 }
13966 {
13967 /* Normally, make_typename_type does not require that the CTX
13968 have complete type in order to allow things like:
13970 template <class T> struct S { typename S<T>::X Y; };
13972 But, such constructs have already been resolved by this
13973 point, so here CTX really should have complete type, unless
13974 it's a partial instantiation. */
13977 {
13981 }
13982 }
13989 {
13992 }
13995 {
13997 {
14001 else
14003 }
14005 {
14009 else
14011 }
14012 }
14014 return cp_build_qualified_type_real
14016 }
14019 {
14031 }
14034 {
14035 tree type;
14051 complain);
14052 }
14055 {
14056 tree type;
14067 {
14069 {
14073 }
14076 }
14087 else
14088 {
14092 /* In a template ~id could be either a complement expression
14093 or an unqualified-id naming a destructor; if instantiating
14094 it produces an expression, it's not an id-expression or
14095 member access. */
14098 }
14103 }
14106 {
14110 }
14114 {
14115 tree r;
14118 {
14120 /* Set the already-substituted type. */
14122 }
14123 else
14131 }
14146 /* We should use one of the expression tsubsts for these codes. */
14152 }
14153 }
14155 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
14156 type of the expression on the left-hand side of the "." or "->"
14157 operator. */
14159 static tree
14162 {
14163 tree name;
14164 tree qualifying_scope;
14165 tree fns;
14166 tree optype;
14171 /* A baselink indicates a function from a base class. Both the
14172 BASELINK_ACCESS_BINFO and the base class referenced may
14173 indicate bases of the template class, rather than the
14174 instantiated class. In addition, lookups that were not
14175 ambiguous before may be ambiguous now. Therefore, we perform
14176 the lookup again. */
14183 {
14190 }
14196 {
14198 {
14202 }
14204 }
14206 /* If lookup found a single function, mark it as used at this
14207 point. (If it lookup found multiple functions the one selected
14208 later by overload resolution will be marked as used at that
14209 point.) */
14216 /* Add back the template arguments, if present. */
14220 unknown_type_node,
14222 template_args);
14223 /* Update the conversion operator type. */
14231 {
14233 qualifying_scope,
14234 object_type);
14236 /* We need to call adjust_result_of_qualified_name_lookup in case the
14237 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14238 so that we still get virtual function binding. */
14240 }
14242 }
14244 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14245 true if the qualified-id will be a postfix-expression in-and-of
14246 itself; false if more of the postfix-expression follows the
14247 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14248 of "&". */
14250 static tree
14254 {
14255 tree expr;
14256 tree scope;
14257 tree name;
14259 tree template_args;
14264 /* Figure out what name to look up. */
14267 {
14277 }
14278 else
14279 {
14282 }
14284 /* Substitute into the qualifying scope. When there are no ARGS, we
14285 are just trying to simplify a non-dependent expression. In that
14286 case the qualifying scope may be dependent, and, in any case,
14287 substituting will not help. */
14290 {
14293 }
14294 else
14298 {
14305 }
14308 {
14310 {
14311 /* A BIT_NOT_EXPR is used to represent a destructor. */
14313 {
14317 }
14318 else
14321 }
14322 else
14326 {
14328 {
14332 }
14334 }
14335 }
14338 {
14340 scope);
14341 /* Remember that there was a reference to this entity. */
14344 }
14347 {
14353 }
14356 {
14359 complain);
14360 else
14362 }
14368 {
14369 expr = (adjust_result_of_qualified_name_lookup
14371 expr = (finish_qualified_id_expr
14375 }
14377 /* Expressions do not generally have reference type. */
14379 /* However, if we're about to form a pointer-to-member, we just
14380 want the referenced member referenced. */
14388 }
14390 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14391 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14392 for tsubst. */
14394 static tree
14397 {
14404 {
14405 /* If we had an initializer but it
14406 instantiated to nothing,
14407 value-initialize the object. This will
14408 only occur when the initializer was a
14409 pack expansion where the parameter packs
14410 used in that expansion were of length
14411 zero. */
14413 complain);
14418 }
14421 }
14423 /* Like tsubst, but deals with expressions. This function just replaces
14424 template parms; to finish processing the resultant expression, use
14425 tsubst_copy_and_build or tsubst_expr. */
14427 static tree
14429 {
14431 tree r;
14439 {
14444 {
14445 /* We get here for a use of 'this' in an NSDMI as part of a
14446 constructor call or as part of an aggregate initialization. */
14448 && ((current_function_decl
14450 || (current_class_ref
14454 /* This can happen for a parameter name used later in a function
14455 declaration (such as in a late-specified return type). Just
14456 make a dummy decl, since it's only used for its type. */
14459 /* Give it the template pattern as its context; its true context
14460 hasn't been instantiated yet and this is good enough for
14461 mangling. */
14463 }
14472 {
14473 tree enum_type;
14474 tree v;
14478 /* There is no need to substitute into namespace-scope
14479 enumerators. */
14482 /* If ARGS is NULL, then T is known to be non-dependent. */
14486 /* Unfortunately, we cannot just call lookup_name here.
14487 Consider:
14489 template <int I> int f() {
14490 enum E { a = I };
14491 struct S { void g() { E e = a; } };
14492 };
14494 When we instantiate f<7>::S::g(), say, lookup_name is not
14495 clever enough to find f<7>::a. */
14496 enum_type
14506 /* We didn't find the name. That should never happen; if
14507 name-lookup found it during preliminary parsing, we
14508 should find it again here during instantiation. */
14510 }
14515 {
14516 /* Check for a local specialization set up by
14517 tsubst_pack_expansion. */
14519 {
14523 }
14525 /* When retrieving a capture pack from a generic lambda, remove the
14526 lambda call op's own template argument list from ARGS. Only the
14527 template arguments active for the closure type should be used to
14528 retrieve the pack specialization. */
14534 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14535 tsubst_decl put in the hash table. */
14537 }
14540 {
14541 tree ctx;
14546 {
14549 {
14553 }
14555 }
14556 }
14566 {
14569 {
14570 /* First try name lookup to find the instantiation. */
14573 {
14574 /* Make sure that the one we found is the one we want. */
14580 }
14584 else
14585 {
14586 /* This can happen for a variable used in a
14587 late-specified return type of a local lambda, or for a
14588 local static or constant. Building a new VAR_DECL
14589 should be OK in all those cases. */
14592 /* Avoid infinite recursion (79640). */
14595 {
14596 /* We can't call cp_finish_decl, so handle the
14597 initializer by hand. */
14608 }
14615 }
14616 /* Remember this for subsequent uses. */
14619 }
14620 }
14621 else
14631 /* An OVERLOAD will always be a non-dependent overload set; an
14632 overload set from function scope will just be represented with an
14633 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14649 {
14650 /* Template template argument like the following example need
14651 special treatment:
14653 template <template <class> class TT> struct C {};
14654 template <class T> struct D {
14655 template <class U> struct E {};
14656 C<E> c; // #1
14657 };
14658 D<int> d; // #2
14660 We are processing the template argument `E' in #1 for
14661 the template instantiation #2. Originally, `E' is a
14662 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14663 have to substitute this with one having context `D<int>'. */
14667 {
14668 /* When rewriting a constructor into a deduction guide, a
14669 non-dependent name can become dependent, so memtmpl<args>
14670 becomes context::template memtmpl<args>. */
14674 }
14676 }
14677 else
14678 /* Ordinary template template argument. */
14689 {
14693 }
14698 {
14707 /* We only want to compute the number of arguments. */
14710 else
14717 {
14719 /* Set TREE_USED for the benefit of -Wunused. */
14723 }
14731 {
14736 else
14742 else
14745 }
14746 else
14748 }
14750 {
14758 }
14759 /* Fall through */
14775 {
14779 }
14782 {
14783 tree object;
14784 tree name;
14789 {
14793 }
14796 {
14806 }
14811 in_decl);
14812 else
14815 }
14853 {
14857 }
14860 {
14865 }
14868 {
14872 }
14875 {
14883 }
14889 {
14896 }
14899 {
14906 }
14909 {
14916 }
14919 {
14920 /* Substituted template arguments */
14929 }
14932 {
14952 }
14977 /* Fall through. */
14980 {
14983 }
14984 else
14988 /* This is handled by tsubst_copy_and_build. */
14992 {
14996 }
14999 /* We shouldn't have built any of these during initial template
15000 generation. Instead, they should be built during instantiation
15001 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15005 {
15015 }
15033 {
15034 /* Instantiate any typedefs in the type. */
15039 }
15042 /* These can sometimes show up in a partial instantiation, but never
15043 involve template parms. */
15057 /* We shouldn't get here, but keep going if !flag_checking. */
15061 }
15062 }
15064 /* Helper function for tsubst_omp_clauses, used for instantiation of
15065 OMP_CLAUSE_DECL of clauses. */
15067 static tree
15069 tree in_decl)
15070 {
15074 /* Handle an OpenMP array section represented as a TREE_LIST (or
15075 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15076 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15077 TREE_LIST. We can handle it exactly the same as an array section
15078 (purpose, value, and a chain), even though the nomenclature
15079 (low_bound, length, etc) is different. */
15081 {
15082 tree low_bound
15088 in_decl);
15097 }
15100 /* Undo convert_from_reference tsubst_expr could have called. */
15106 }
15108 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15110 static tree
15113 {
15118 {
15124 {
15127 {
15133 }
15134 /* FALLTHRU */
15149 in_decl);
15181 {
15184 {
15191 }
15192 else
15194 }
15197 in_decl);
15203 in_decl);
15211 in_decl);
15213 {
15216 }
15221 else
15224 in_decl,
15248 }
15251 {
15261 /* tsubst_expr on SCOPE_REF results in returning
15262 finish_non_static_data_member result. Undo that here. */
15266 {
15271 {
15275 CASE_CONVERT:
15284 /* FALLTHRU */
15288 }
15289 }
15295 {
15298 {
15302 }
15303 }
15307 }
15308 }
15312 {
15317 {
15320 }
15321 }
15323 }
15325 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15327 static tree
15329 tree in_decl)
15330 {
15331 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15351 {
15354 else
15355 {
15359 }
15360 }
15365 #undef RECUR
15366 }
15368 /* Used to temporarily communicate the list of #pragma omp parallel
15369 clauses to #pragma omp for instantiation if they are combined
15370 together. */
15374 /* Substitute one OMP_FOR iterator. */
15376 static void
15381 {
15382 #define RECUR(NODE) \
15383 tsubst_expr ((NODE), args, complain, in_decl, \
15384 integral_constant_expression_p)
15391 {
15394 }
15400 {
15401 /* We need to jump through some hoops to handle declarations in the
15402 init-statement, since we might need to handle auto deduction,
15403 but we need to keep control of initialization. */
15407 }
15408 else
15409 {
15411 {
15414 {
15418 {
15422 CASE_CONVERT:
15430 {
15433 }
15434 /* FALLTHRU */
15438 }
15439 }
15440 }
15441 else
15443 }
15454 {
15456 {
15457 /* Declare the variable, but don't let that initialize it. */
15462 }
15467 {
15472 }
15473 else
15480 }
15483 {
15484 /* Declare and initialize the variable. */
15487 }
15489 {
15493 {
15495 {
15501 {
15504 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15509 }
15512 {
15514 decl);
15516 }
15519 {
15521 decl);
15523 }
15524 else
15526 }
15529 }
15531 {
15536 {
15539 }
15540 }
15541 }
15544 {
15548 }
15549 else
15553 {
15564 {
15572 }
15573 else
15579 {
15585 }
15589 {
15597 }
15598 else
15604 }
15610 #undef RECUR
15611 }
15613 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15614 of OMP_TARGET's body. */
15616 static tree
15618 {
15621 {
15630 }
15632 }
15634 /* Helper function for tsubst_expr. For decomposition declaration
15635 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15636 also the corresponding decls representing the identifiers
15637 of the decomposition declaration. Return DECL if successful
15638 or error_mark_node otherwise, set *FIRST to the first decl
15639 in the list chained through DECL_CHAIN and *CNT to the number
15640 of such decls. */
15642 static tree
15646 {
15651 decl2
15656 {
15658 {
15661 }
15677 {
15680 }
15681 else
15683 }
15686 }
15688 /* Like tsubst_copy for expressions, etc. but also does semantic
15689 processing. */
15691 tree
15694 {
15695 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15696 #define RECUR(NODE) \
15697 tsubst_expr ((NODE), args, complain, in_decl, \
15698 integral_constant_expression_p)
15701 tree r;
15702 location_t loc;
15714 {
15716 {
15717 tree_stmt_iterator i;
15721 }
15736 else
15745 {
15747 tree init;
15753 {
15763 else
15765 }
15767 {
15768 /* Don't build up decls for a variadic capture proxy, we'll
15769 instantiate the elements directly as needed. */
15771 }
15772 else
15773 {
15777 {
15778 /* By marking the declaration as instantiated, we avoid
15779 trying to instantiate it. Since instantiate_decl can't
15780 handle local variables, and since we've already done
15781 all that needs to be done, that's the right thing to
15782 do. */
15787 /* Anonymous aggregates are a special case. */
15790 {
15793 {
15797 }
15799 }
15805 {
15810 }
15811 else
15812 {
15817 {
15818 /* For __PRETTY_FUNCTION__ we have to adjust the
15819 initializer. */
15823 }
15824 else
15828 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15834 {
15836 tree first;
15842 }
15843 }
15844 }
15845 }
15848 }
15863 {
15871 {
15873 tree first;
15878 }
15879 else
15884 }
15910 else
15911 {
15918 }
15924 {
15933 }
15941 else
15949 else
15970 {
15977 }
15981 {
15983 tree label;
15990 }
15996 /* Computed goto's must be tsubst'd into. On the other hand,
15997 non-computed gotos must not be; the identifier in question
15998 will have no binding. */
16000 else
16006 {
16022 }
16027 {
16032 }
16033 else
16034 {
16039 else
16046 else
16052 else
16054 }
16058 {
16062 {
16064 /* Prevent instantiate_decl from trying to instantiate
16065 this variable. We've already done all that needs to be
16066 done. */
16069 }
16074 }
16080 {
16081 /* Local classes are not independent templates; they are
16082 instantiated along with their containing function. And this
16083 way we don't have to deal with pushing out of one local class
16084 to instantiate a member of another local class. */
16085 tree fn;
16086 /* Closures are handled by the LAMBDA_EXPR. */
16093 }
16097 {
16098 tree condition;
16101 condition =
16103 args,
16112 }
16118 in_decl);
16155 {
16170 in_decl);
16172 {
16179 }
16191 integral_constant_expression_p);
16202 else
16203 {
16211 }
16215 }
16220 /* FALLTHRU */
16227 in_decl);
16244 in_decl);
16255 {
16258 {
16259 /* For combined target teams, ensure the num_teams and
16260 thread_limit clause expressions are evaluated on the host,
16261 before entering the target construct. */
16262 tree c;
16268 {
16277 OMP_CLAUSE_FIRSTPRIVATE);
16281 }
16282 }
16283 }
16343 {
16348 {
16351 }
16357 }
16358 else
16359 {
16366 {
16369 }
16372 {
16377 {
16380 }
16386 }
16387 else
16388 {
16392 }
16395 }
16399 {
16405 {
16409 {
16414 }
16418 }
16419 else
16420 {
16425 }
16426 }
16430 {
16434 }
16454 /* If the first operand was a statement, we're done with it. */
16458 complain));
16470 integral_constant_expression_p));
16471 }
16474 out:
16477 #undef RECUR
16478 #undef RETURN
16479 }
16481 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16482 function. For description of the body see comment above
16483 cp_parser_omp_declare_reduction_exprs. */
16485 static void
16487 {
16493 tree_stmt_iterator tsi;
16504 {
16523 }
16525 {
16545 }
16546 }
16548 /* T is a postfix-expression that is not being used in a function
16549 call. Return the substituted version of T. */
16551 static tree
16553 tsubst_flags_t complain,
16554 tree in_decl)
16555 {
16559 else
16565 }
16567 /* Like tsubst but deals with expressions and performs semantic
16568 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16570 tree
16572 tree args,
16573 tsubst_flags_t complain,
16574 tree in_decl,
16577 {
16578 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16579 #define RECUR(NODE) \
16580 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16582 integral_constant_expression_p)
16585 location_t loc;
16594 /* N3276 decltype magic only applies to calls at the top level or on the
16595 right side of a comma. */
16600 {
16603 /* Fall through. */
16605 {
16606 tree decl;
16607 cp_id_kind idk;
16612 {
16615 }
16617 /* Look up the name. */
16620 /* By convention, expressions use ERROR_MARK_NODE to indicate
16621 failure, not NULL_TREE. */
16627 integral_constant_expression_p,
16635 input_location);
16639 {
16643 }
16645 }
16648 {
16649 tree object;
16659 {
16664 }
16670 {
16673 }
16674 else
16681 else
16683 }
16686 {
16690 {
16691 /* A type conversion to reference type will be enclosed in
16692 such an indirect ref, but the substitution of the cast
16693 will have also added such an indirect ref. */
16696 }
16697 else
16705 }
16708 {
16712 }
16715 {
16722 flags));
16723 }
16726 {
16730 }
16737 {
16738 tree type;
16744 {
16749 }
16755 {
16773 }
16776 }
16810 else
16812 in_decl);
16847 {
16854 tree r = build_x_binary_op
16856 op0,
16858 ? ERROR_MARK
16860 op1,
16862 ? ERROR_MARK
16870 }
16873 {
16877 }
16890 {
16899 }
16904 /* Fall through */
16907 {
16908 tree r;
16914 {
16915 /* When there are no ARGS, we are trying to evaluate a
16916 non-dependent expression from the parser. Trying to do
16917 the substitutions may not work. */
16920 }
16921 else
16922 {
16927 else
16930 /*integral_constant_expression_p=*/
16934 }
16938 else
16942 {
16944 {
16946 {
16950 }
16951 else
16955 }
16957 }
16959 }
16962 {
16972 }
16988 {
16992 tree r = build_x_modify_expr
16995 /* TREE_NO_WARNING must be set if either the expression was
16996 parenthesized or it uses an operator such as >>= rather
16997 than plain assignment. In the former case, it was already
16998 set and must be copied. In the latter case,
16999 build_x_modify_expr sets it and it must not be reset
17000 here. */
17005 }
17010 /* Remember that there was a reference to this entity. */
17017 {
17022 tree ret;
17026 else
17027 {
17031 }
17033 /* If there was an initializer in the original tree, but it
17034 instantiated to an empty list, then we should pass a
17035 non-NULL empty vector to tell build_new that it was an
17036 empty initializer() rather than no initializer. This can
17037 only happen when the initializer is a pack expansion whose
17038 parameter packs are of length zero. */
17041 else
17042 {
17046 else
17047 {
17050 }
17051 }
17057 complain);
17065 }
17068 {
17074 complain));
17075 }
17078 {
17082 integral_constant_expression_p);
17084 op0,
17087 }
17090 {
17091 tree function;
17096 tree ret;
17099 /* Internal function with no arguments. */
17103 /* When we parsed the expression, we determined whether or
17104 not Koenig lookup should be performed. */
17107 {
17110 }
17112 {
17117 }
17119 {
17120 /* Do nothing; calling tsubst_copy_and_build on an identifier
17121 would incorrectly perform unqualified lookup again.
17123 Note that we can also have an IDENTIFIER_NODE if the earlier
17124 unqualified lookup found a member function; in that case
17125 koenig_p will be false and we do want to do the lookup
17126 again to find the instantiated member function.
17128 FIXME but doing that causes c++/15272, so we need to stop
17129 using IDENTIFIER_NODE in that situation. */
17131 }
17132 else
17133 {
17135 {
17141 }
17142 else
17147 /* Avoid error about taking the address of a constructor. */
17151 in_decl,
17153 integral_constant_expression_p);
17157 }
17162 {
17167 else
17168 {
17169 /* Expand the pack expansion and push each entry onto
17170 CALL_ARGS. */
17173 {
17178 {
17183 }
17184 }
17185 else
17186 {
17187 /* A partial substitution. Add one entry. */
17189 }
17190 }
17191 }
17193 /* We do not perform argument-dependent lookup if normal
17194 lookup finds a non-function, in accordance with the
17195 expected resolution of DR 218. */
17198 /* If lookup found a member function, the Koenig lookup is
17199 not appropriate, even if an unqualified-name was used
17200 to denote the function. */
17203 /* Only do this when substitution turns a dependent call
17204 into a non-dependent call. */
17212 {
17214 {
17215 /* For backwards compatibility and good diagnostics, try
17216 the unqualified lookup again if we aren't in SFINAE
17217 context. */
17218 tree unq = (tsubst_copy_and_build
17220 integral_constant_expression_p));
17222 {
17225 }
17228 {
17229 /* In a lambda fn, we have to be careful to not
17230 introduce new this captures. Legacy code can't
17231 be using lambdas anyway, so it's ok to be
17232 stricter. */
17237 "and no declarations were found by "
17238 "argument-dependent lookup at the point "
17245 else
17249 {
17261 {
17263 input_location);
17265 "declarations in dependent base %qT are "
17271 else
17275 }
17276 else
17278 "%qD declared here, later in the "
17281 {
17284 }
17285 }
17288 }
17289 }
17291 {
17296 }
17297 }
17299 /* Remember that there was a reference to this entity. */
17303 {
17306 }
17308 /* Put back tf_decltype for the actual call. */
17313 {
17317 {
17319 "wrong number of arguments to "
17322 }
17323 else
17325 input_location),
17330 /* Unsupported internal function with arguments. */
17332 }
17335 complain);
17337 {
17352 complain);
17353 else
17354 ret = (build_new_method_call
17359 complain));
17360 }
17361 else
17364 koenig_p,
17365 complain);
17370 {
17376 {
17382 {
17384 /* The thunk location is not interesting. */
17386 }
17387 }
17388 }
17391 }
17394 {
17400 {
17402 {
17407 }
17408 else
17409 {
17414 }
17416 }
17417 else
17418 {
17421 }
17425 }
17428 {
17433 input_location));
17434 }
17437 {
17445 {
17446 /* We have pack expansions, so expand those and
17447 create a new list out of it. */
17450 tree chain;
17453 /* Expand the argument expressions. */
17461 /* Build the rest of the list. */
17466 /* Determine the number of arguments. */
17468 {
17471 }
17474 else
17475 {
17476 /* Since we only performed a partial substitution into
17477 the argument pack, we only RETURN (a single list
17478 node. */
17485 }
17487 /* Convert the argument vectors into a TREE_LIST */
17490 {
17491 /* Grab the Ith values. */
17492 i--;
17495 value
17499 /* Build the list (backwards). */
17501 }
17504 }
17520 }
17523 {
17524 tree object;
17525 tree object_type;
17526 tree member;
17527 tree r;
17531 /* Remember that there was a reference to this entity. */
17542 else
17548 {
17553 }
17557 {
17559 {
17564 {
17567 }
17569 {
17574 }
17575 }
17576 }
17579 {
17580 /* Lookup the template functions now that we know what the
17581 scope is. */
17589 {
17592 args);
17593 member = (adjust_result_of_qualified_name_lookup
17595 object_type));
17596 }
17597 else
17598 {
17600 input_location);
17602 }
17603 }
17607 {
17609 {
17613 else
17616 }
17618 }
17622 complain);
17626 }
17633 {
17641 tree r;
17646 /* digest_init will do the wrong thing if we let it. */
17650 /* We do not want to process the index of aggregate
17651 initializers as they are identifier nodes which will be
17652 looked up by digest_init. */
17658 {
17660 /* An identifier index is looked up in the type
17661 being initialized, not the current scope. */
17666 {
17667 /* Substitute into the pack expansion. */
17669 in_decl);
17673 ;
17675 /* Just move the argument into place. */
17677 else
17678 {
17679 /* Update the length of the final CONSTRUCTOR
17680 arguments vector, and note that we will need to
17681 copy.*/
17684 }
17685 }
17686 else
17688 }
17691 {
17696 {
17698 {
17703 }
17704 else
17706 }
17707 }
17717 }
17720 {
17723 {
17726 }
17727 else
17728 {
17731 }
17732 }
17738 {
17739 /* We don't build decls for an instantiation of a
17740 variadic capture proxy, we instantiate the elements
17741 when needed. */
17744 }
17745 /* Fall through */
17748 {
17750 /* ??? We're doing a subset of finish_id_expression here. */
17752 && !processing_template_decl
17753 && !cp_unevaluated_operand
17756 {
17758 /* Replace an evaluated use of the thread_local variable with
17759 a call to its wrapper. */
17761 }
17763 {
17767 }
17770 /* If the original type was a reference, we'll be wrapped in
17771 the appropriate INDIRECT_REF. */
17774 }
17777 {
17781 }
17784 {
17785 tree object_ptr
17792 }
17799 {
17810 }
17813 {
17819 integral_constant_expression_p);
17823 /* If the resulting list of expression statement is empty,
17824 fold it further into void_node. */
17829 }
17832 {
17850 /* For a function or variable scope, we want to use tsubst so that we
17851 don't complain about referring to an auto before deduction. */
17854 {
17855 /* Look up the parameter we want directly, as tsubst_copy
17856 doesn't do what we need. */
17862 /* FIXME Work around the parm not having DECL_CONTEXT set. */
17865 }
17867 /* For a field, use tsubst_copy so that we look up the existing field
17868 rather than build a new one. */
17870 else
17877 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17879 /* Now that we know visibility, instantiate the type so we have a
17880 declaration of the op() for later calls to lambda_function. */
17891 }
17894 /* We can get here for a constant initializer of non-dependent type.
17895 FIXME stop folding in cp_parser_initializer_clause. */
17896 {
17898 complain);
17900 }
17904 integral_constant_expression_p));
17910 {
17915 complain));
17916 }
17922 /* Handle Objective-C++ constructs, if appropriate. */
17923 {
17924 tree subst
17929 }
17931 }
17933 #undef RECUR
17934 #undef RETURN
17935 out:
17938 }
17940 /* Verify that the instantiated ARGS are valid. For type arguments,
17941 make sure that the type's linkage is ok. For non-type arguments,
17942 make sure they are constants if they are integral or enumerations.
17943 Emit an error under control of COMPLAIN, and return TRUE on error. */
17945 static bool
17947 {
17951 {
17961 }
17963 {
17964 /* [basic.link]: A name with no linkage (notably, the name
17965 of a class or enumeration declared in a local scope)
17966 shall not be used to declare an entity with linkage.
17967 This implies that names with no linkage cannot be used as
17968 template arguments
17970 DR 757 relaxes this restriction for C++0x. */
17975 {
17976 /* DR 488 makes use of a type with no linkage cause
17977 type deduction to fail. */
17979 {
17982 else
17985 }
17987 }
17988 /* In order to avoid all sorts of complications, we do not
17989 allow variably-modified types as template arguments. */
17991 {
17995 }
17996 }
17997 /* Class template and alias template arguments should be OK. */
17999 ;
18000 /* A non-type argument of integral or enumerated type must be a
18001 constant. */
18006 {
18010 }
18012 }
18014 static bool
18016 {
18021 {
18024 }
18028 }
18030 /* We're out of SFINAE context now, so generate diagnostics for the access
18031 errors we saw earlier when instantiating D from TMPL and ARGS. */
18033 static void
18035 {
18047 }
18049 /* Instantiate the indicated variable, function, or alias template TMPL with
18050 the template arguments in TARG_PTR. */
18052 static tree
18054 {
18056 tree fndecl;
18057 tree gen_tmpl;
18058 tree spec;
18066 /* If this function is a clone, handle it specially. */
18068 {
18069 tree spec;
18070 tree clone;
18072 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18073 DECL_CLONED_FUNCTION. */
18079 /* Look for the clone. */
18083 /* We should always have found the clone by now. */
18086 }
18091 /* Check to see if we already have this specialization. */
18095 /* targ_ptr only has the innermost template args, so add the outer ones
18096 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18097 the case of a non-dependent call within a template definition). */
18098 targ_ptr = (add_outermost_template_args
18100 targ_ptr));
18102 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18103 but it doesn't seem to be on the hot path. */
18112 {
18114 {
18118 }
18120 }
18123 complain))
18126 /* We are building a FUNCTION_DECL, during which the access of its
18127 parameters and return types have to be checked. However this
18128 FUNCTION_DECL which is the desired context for access checking
18129 is not built yet. We solve this chicken-and-egg problem by
18130 deferring all checks until we have the FUNCTION_DECL. */
18133 /* Instantiation of the function happens in the context of the function
18134 template, not the context of the overload resolution we're doing. */
18136 /* If there are dependent arguments, e.g. because we're doing partial
18137 ordering, make sure processing_template_decl stays set. */
18141 {
18145 }
18151 {
18152 /* We need to determine if we're using a partial or explicit
18153 specialization now, because the type of the variable could be
18154 different. */
18160 {
18165 }
18166 }
18168 /* Substitute template parameters to obtain the specialization. */
18176 {
18179 }
18181 /* The DECL_TI_TEMPLATE should always be the immediate parent
18182 template, not the most general template. */
18186 /* Now we know the specialization, compute access previously
18187 deferred. Do no access control for inheriting constructors,
18188 as we already checked access for the inherited constructor. */
18191 {
18196 }
18199 /* If we've just instantiated the main entry point for a function,
18200 instantiate all the alternate entry points as well. We do this
18201 by cloning the instantiation of the main entry point, not by
18202 instantiating the template clones. */
18207 {
18209 {
18210 /* Remember to reinstantiate when we're out of SFINAE so the user
18211 can see the errors. */
18213 }
18215 }
18217 }
18219 /* Wrapper for instantiate_template_1. */
18221 tree
18223 {
18224 tree ret;
18229 }
18231 /* Instantiate the alias template TMPL with ARGS. Also push a template
18232 instantiation level, which instantiate_template doesn't do because
18233 functions and variables have sufficient context established by the
18234 callers. */
18236 static tree
18238 {
18245 {
18248 }
18250 args =
18258 /* We can't free this if a pending_template entry or last_error_tinst_level
18259 is pointing at it. */
18265 }
18267 /* PARM is a template parameter pack for FN. Returns true iff
18268 PARM is used in a deducible way in the argument list of FN. */
18270 static bool
18272 {
18275 {
18277 tree packs;
18283 {
18284 /* The template parameter pack is used in a function parameter
18285 pack. If this is the end of the parameter list, the
18286 template parameter pack is deducible. */
18289 else
18290 /* Otherwise, not. Well, it could be deduced from
18291 a non-pack parameter, but doing so would end up with
18292 a deduction mismatch, so don't bother. */
18294 }
18295 }
18296 /* The template parameter pack isn't used in any function parameter
18297 packs, but it might be used deeper, e.g. tuple<Args...>. */
18299 }
18301 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18302 NARGS elements of the arguments that are being used when calling
18303 it. TARGS is a vector into which the deduced template arguments
18304 are placed.
18306 Returns either a FUNCTION_DECL for the matching specialization of FN or
18307 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18308 true, diagnostics will be printed to explain why it failed.
18310 If FN is a conversion operator, or we are trying to produce a specific
18311 specialization, RETURN_TYPE is the return type desired.
18313 The EXPLICIT_TARGS are explicit template arguments provided via a
18314 template-id.
18316 The parameter STRICT is one of:
18318 DEDUCE_CALL:
18319 We are deducing arguments for a function call, as in
18320 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18321 deducing arguments for a call to the result of a conversion
18322 function template, as in [over.call.object].
18324 DEDUCE_CONV:
18325 We are deducing arguments for a conversion function, as in
18326 [temp.deduct.conv].
18328 DEDUCE_EXACT:
18329 We are deducing arguments when doing an explicit instantiation
18330 as in [temp.explicit], when determining an explicit specialization
18331 as in [temp.expl.spec], or when taking the address of a function
18332 template, as in [temp.deduct.funcaddr]. */
18334 tree
18336 tree explicit_targs,
18337 tree targs,
18340 tree return_type,
18341 unification_kind_t strict,
18345 {
18346 tree parms;
18347 tree fntype;
18360 tree tinst;
18366 full_targs = (add_outermost_template_args
18368 targs));
18373 /* In C++0x, it's possible to have a function template whose type depends
18374 on itself recursively. This is most obvious with decltype, but can also
18375 occur with enumeration scope (c++/48969). So we need to catch infinite
18376 recursion and reject the substitution at deduction time; this function
18377 will return error_mark_node for any repeated substitution.
18379 This also catches excessive recursion such as when f<N> depends on
18380 f<N-1> across all integers, and returns error_mark_node for all the
18381 substitutions back up to the initial one.
18383 This is, of course, not reentrant. */
18393 {
18394 /* [temp.deduct]
18396 The specified template arguments must match the template
18397 parameters in kind (i.e., type, nontype, template), and there
18398 must not be more arguments than there are parameters;
18399 otherwise type deduction fails.
18401 Nontype arguments must match the types of the corresponding
18402 nontype template parameters, or must be convertible to the
18403 types of the corresponding nontype parameters as specified in
18404 _temp.arg.nontype_, otherwise type deduction fails.
18406 All references in the function type of the function template
18407 to the corresponding template parameters are replaced by the
18408 specified template argument values. If a substitution in a
18409 template parameter or in the function type of the function
18410 template results in an invalid type, type deduction fails. */
18421 explicit_targs);
18423 /* Adjust any explicit template arguments before entering the
18424 substitution context. */
18425 explicit_targs
18427 complain,
18433 /* Substitute the explicit args into the function type. This is
18434 necessary so that, for instance, explicitly declared function
18435 arguments can match null pointed constants. If we were given
18436 an incomplete set of explicit args, we must not do semantic
18437 processing during substitution as we could create partial
18438 instantiations. */
18440 {
18445 /* Dig out the actual parm. */
18448 {
18451 }
18453 {
18456 }
18459 /* No explicit argument for this template parameter. */
18463 {
18464 /* Mark the argument pack as "incomplete". We could
18465 still deduce more arguments during unification.
18466 We remove this mark in type_unification_real. */
18468 {
18472 }
18474 /* We have some incomplete argument packs. */
18476 }
18477 }
18481 {
18484 }
18487 /* Ignore any access checks; we'll see them again in
18488 instantiate_template and they might have the wrong
18489 access path at this point. */
18501 /* Place the explicitly specified arguments in TARGS. */
18505 }
18507 /* Never do unification on the 'this' parameter. */
18511 {
18512 /* We're deducing for a call to the result of a template conversion
18513 function. The parms we really want are in return_type. */
18517 }
18519 {
18528 }
18530 /* We allow incomplete unification without an error message here
18531 because the standard doesn't seem to explicitly prohibit it. Our
18532 callers must be ready to deal with unification failures in any
18533 event. */
18536 /* If we aren't explaining yet, push tinst context so we can see where
18537 any errors (e.g. from class instantiations triggered by instantiation
18538 of default template arguments) come from. If we are explaining, this
18539 context is redundant. */
18541 {
18544 }
18546 /* type_unification_real will pass back any access checks from default
18547 template argument substitution. */
18559 /* Now that we have bindings for all of the template arguments,
18560 ensure that the arguments deduced for the template template
18561 parameters have compatible template parameter lists. We cannot
18562 check this property before we have deduced all template
18563 arguments, because the template parameter types of a template
18564 template parameter might depend on prior template parameters
18565 deduced after the template template parameter. The following
18566 ill-formed example illustrates this issue:
18568 template<typename T, template<T> class C> void f(C<5>, T);
18570 template<int N> struct X {};
18572 void g() {
18573 f(X<5>(), 5l); // error: template argument deduction fails
18574 }
18576 The template parameter list of 'C' depends on the template type
18577 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18578 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18579 time that we deduce 'C'. */
18582 {
18585 }
18587 /* All is well so far. Now, check:
18589 [temp.deduct]
18591 When all template arguments have been deduced, all uses of
18592 template parameters in nondeduced contexts are replaced with
18593 the corresponding deduced argument values. If the
18594 substitution results in an invalid type, as described above,
18595 type deduction fails. */
18598 {
18601 }
18603 /* Also collect access checks from the instantiation. */
18616 /* Now perform any access checks encountered during substitution. */
18623 /* If we're looking for an exact match, check that what we got
18624 is indeed an exact match. It might not be if some template
18625 parameters are used in non-deduced contexts. But don't check
18626 for an exact match if we have dependent template arguments;
18627 in that case we're doing partial ordering, and we already know
18628 that we have two candidates that will provide the actual type. */
18630 {
18634 tree sarg
18640 {
18644 }
18645 }
18647 /* After doing deduction with the inherited constructor, actually return an
18648 instantiation of the inheriting constructor. */
18654 fail:
18657 {
18659 /* Reset once we're all the way out. */
18661 }
18663 /* We can't free this if a pending_template entry or last_error_tinst_level
18664 is pointing at it. */
18670 }
18672 /* Adjust types before performing type deduction, as described in
18673 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
18674 sections are symmetric. PARM is the type of a function parameter
18675 or the return type of the conversion function. ARG is the type of
18676 the argument passed to the call, or the type of the value
18677 initialized with the result of the conversion function.
18678 ARG_EXPR is the original argument expression, which may be null. */
18680 static int
18684 tree arg_expr)
18685 {
18689 {
18694 /* Swap PARM and ARG throughout the remainder of this
18695 function; the handling is precisely symmetric since PARM
18696 will initialize ARG rather than vice versa. */
18701 /* Core issue #873: Do the DR606 thing (see below) for these cases,
18702 too, but here handle it by stripping the reference from PARM
18703 rather than by adding it to ARG. */
18711 /* Nothing else to do in this case. */
18716 }
18719 {
18720 /* [temp.deduct.call]
18722 If P is not a reference type:
18724 --If A is an array type, the pointer type produced by the
18725 array-to-pointer standard conversion (_conv.array_) is
18726 used in place of A for type deduction; otherwise,
18728 --If A is a function type, the pointer type produced by
18729 the function-to-pointer standard conversion
18730 (_conv.func_) is used in place of A for type deduction;
18731 otherwise,
18733 --If A is a cv-qualified type, the top level
18734 cv-qualifiers of A's type are ignored for type
18735 deduction. */
18740 else
18742 }
18744 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
18745 reference to a cv-unqualified template parameter that does not represent a
18746 template parameter of a class template (during class template argument
18747 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
18748 an lvalue, the type "lvalue reference to A" is used in place of A for type
18749 deduction. */
18756 /* try_one_overload doesn't provide an arg_expr, but
18757 functions are always lvalues. */
18761 /* [temp.deduct.call]
18763 If P is a cv-qualified type, the top level cv-qualifiers
18764 of P's type are ignored for type deduction. If P is a
18765 reference type, the type referred to by P is used for
18766 type deduction. */
18769 {
18772 }
18774 /* DR 322. For conversion deduction, remove a reference type on parm
18775 too (which has been swapped into ARG). */
18780 }
18782 /* Subroutine of unify_one_argument. PARM is a function parameter of a
18783 template which does contain any deducible template parameters; check if
18784 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
18785 unify_one_argument. */
18787 static int
18790 {
18791 tree type;
18795 else
18802 {
18806 }
18808 {
18813 }
18817 else
18819 }
18823 /* Returns true iff the expression EXPR is one from which a template
18824 argument can be deduced. In other words, if it's an undecorated
18825 use of a template non-type parameter. */
18827 static bool
18829 {
18830 /* Strip implicit conversions. */
18834 }
18836 /* Returns true iff the array domain DOMAIN uses a template parameter in a
18837 deducible way; that is, if it has a max value of <PARM> - 1. */
18839 static bool
18841 {
18850 }
18852 /* Returns true iff the template arguments ARGS use a template parameter
18853 in a deducible way. */
18855 static bool
18857 {
18859 {
18864 else
18865 {
18872 else
18874 }
18877 }
18879 }
18881 /* Returns true iff TYPE contains any deducible references to template
18882 parameters, as per 14.8.2.5. */
18884 static bool
18886 {
18890 /* T
18891 cv-list T
18892 TT<T>
18893 TT<i>
18894 TT<> */
18899 /* T*
18900 T&
18901 T&& */
18905 /* T[integer-constant ]
18906 type [i] */
18911 /* T type ::*
18912 type T::*
18913 T T::*
18914 T (type ::*)()
18915 type (T::*)()
18916 type (type ::*)(T)
18917 type (T::*)(T)
18918 T (type ::*)(T)
18919 T (T::*)()
18920 T (T::*)(T) */
18923 || (uses_deducible_template_parms
18926 /* template-name <T> (where template-name refers to a class template)
18927 template-name <i> (where template-name refers to a class template) */
18934 /* type (T)
18935 T()
18936 T(T) */
18939 {
18948 }
18951 }
18953 /* Subroutine of type_unification_real and unify_pack_expansion to
18954 handle unification of a single P/A pair. Parameters are as
18955 for those functions. */
18957 static int
18961 {
18968 /* We can't deduce anything from this, but we might get all the
18969 template args from other function args. */
18972 /* Implicit conversions (Clause 4) will be performed on a function
18973 argument to convert it to the type of the corresponding function
18974 parameter if the parameter type contains no template-parameters that
18975 participate in template argument deduction. */
18978 /* For function parameters with no deducible template parameters,
18979 just return. We'll check non-dependent conversions later. */
18983 {
18985 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
18986 | UNIFY_ALLOW_MORE_CV_QUAL
19000 }
19002 /* We only do these transformations if this is the top-level
19003 parameter_type_list in a call or declaration matching; in other
19004 situations (nested function declarators, template argument lists) we
19005 won't be comparing a type to an expression, and we don't do any type
19006 adjustments. */
19008 {
19010 {
19013 {
19014 /* [temp.deduct.type] A template-argument can be
19015 deduced from a pointer to function or pointer
19016 to member function argument if the set of
19017 overloaded functions does not contain function
19018 templates and at most one of a set of
19019 overloaded functions provides a unique
19020 match. */
19027 }
19033 }
19035 arg_strict |=
19037 }
19038 else
19043 /* For deduction from an init-list we need the actual list. */
19047 }
19049 /* for_each_template_parm callback that always returns 0. */
19051 static int
19053 {
19055 }
19057 /* for_each_template_parm any_fn callback to handle deduction of a template
19058 type argument from the type of an array bound. */
19060 static int
19062 {
19070 {
19076 }
19078 /* Keep walking. */
19080 }
19082 /* Try to deduce any not-yet-deduced template type arguments from the type of
19083 an array bound. This is handled separately from unify because 14.8.2.5 says
19084 "The type of a type parameter is only deduced from an array bound if it is
19085 not otherwise deduced." */
19087 static void
19089 {
19094 }
19096 /* Most parms like fn_type_unification.
19098 If SUBR is 1, we're being called recursively (to unify the
19099 arguments of a function or method parameter of a function
19100 template).
19102 CHECKS is a pointer to a vector of access checks encountered while
19103 substituting default template arguments. */
19105 static int
19107 tree full_targs,
19108 tree xparms,
19112 unification_kind_t strict,
19116 {
19121 tree parms;
19132 /* Reset the number of non-defaulted template arguments contained
19133 in TARGS. */
19136 again:
19144 {
19149 /* For a function parameter pack that occurs at the end of the
19150 parameter-declaration-list, the type A of each remaining
19151 argument of the call is compared with the type P of the
19152 declarator-id of the function parameter pack. */
19158 /* For a function parameter pack that does not occur at the
19159 end of the parameter-declaration-list, the type of the
19160 parameter pack is a non-deduced context. */
19167 explain_p))
19169 }
19174 {
19175 /* Unify the remaining arguments with the pack expansion type. */
19176 tree argvec;
19179 /* Allocate a TREE_VEC and copy in all of the arguments */
19184 /* Copy the parameter into parmvec. */
19190 /* Advance to the end of the list of parameters. */
19192 }
19194 /* Fail if we've reached the end of the parm list, and more args
19195 are present, and the parm list isn't variadic. */
19198 /* Fail if parms are left and they don't have default values and
19199 they aren't all deduced as empty packs (c++/57397). This is
19200 consistent with sufficient_parms_p. */
19203 {
19207 do
19208 {
19211 count++;
19213 }
19217 type_pack_p);
19218 }
19221 {
19222 tsubst_flags_t complain = (explain_p
19223 ? tf_warning_or_error
19228 {
19232 /* Clear the "incomplete" flags on all argument packs now so that
19233 substituting them into later default arguments works. */
19235 {
19238 }
19246 {
19251 }
19253 /* If this is an undeduced nontype parameter that depends on
19254 a type parameter, try another pass; its type may have been
19255 deduced from a later argument than the one from which
19256 this parameter can be deduced. */
19260 {
19263 }
19265 /* Core issue #226 (C++0x) [temp.deduct]:
19267 If a template argument has not been deduced, its
19268 default template argument, if any, is used.
19270 When we are in C++98 mode, TREE_PURPOSE will either
19271 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19272 to explicitly check cxx_dialect here. */
19274 /* OK, there is a default argument. Wait until after the
19275 conversion check to do substitution. */
19278 /* If the type parameter is a parameter pack, then it will
19279 be deduced to an empty parameter pack. */
19281 {
19282 tree arg;
19285 {
19289 }
19290 else
19297 }
19300 }
19302 /* DR 1391: All parameters have args, now check non-dependent parms for
19303 convertibility. */
19307 {
19313 /* For a function parameter pack that occurs at the end of the
19314 parameter-declaration-list, the type A of each remaining
19315 argument of the call is compared with the type P of the
19316 declarator-id of the function parameter pack. */
19322 /* For a function parameter pack that does not occur at the
19323 end of the parameter-declaration-list, the type of the
19324 parameter pack is a non-deduced context. */
19333 explain_p))
19335 }
19337 /* Now substitute into the default template arguments. */
19339 {
19363 else
19371 {
19373 /* The position of the first default template argument,
19374 is also the number of non-defaulted arguments in TARGS.
19375 Record that. */
19378 }
19379 }
19383 }
19389 }
19391 /* Subroutine of type_unification_real. Args are like the variables
19392 at the call site. ARG is an overloaded function (or template-id);
19393 we try deducing template args from each of the overloads, and if
19394 only one succeeds, we go with that. Modifies TARGS and returns
19395 true on success. */
19397 static bool
19399 tree targs,
19400 tree parm,
19401 tree arg,
19402 unification_kind_t strict,
19405 {
19412 {
19415 }
19416 else
19420 /* Handle `&x' where `x' is some static or non-static member
19421 function name. */
19427 /* Strip baselink information. */
19432 {
19433 /* If we got some explicit template args, we need to plug them into
19434 the affected templates before we try to unify, in case the
19435 explicit args will completely resolve the templates in question. */
19442 {
19455 {
19460 {
19463 }
19464 }
19467 }
19468 /* If no templates (or more than one) are fully resolved by the
19469 explicit arguments, this template-id is a non-deduced context; it
19470 could still be OK if we deduce all template arguments for the
19471 enclosing call through other arguments. */
19474 }
19477 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19478 -- but the deduction does not succeed because the expression is
19479 not just the function on its own. */
19481 else
19487 {
19490 }
19492 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19493 to function or pointer to member function argument if the set of
19494 overloaded functions does not contain function templates and at most
19495 one of a set of overloaded functions provides a unique match.
19497 So if we found multiple possibilities, we return success but don't
19498 deduce anything. */
19501 {
19505 {
19510 /* Don't forget explicit template arguments in a pack. */
19514 }
19515 }
19520 }
19522 /* Core DR 115: In contexts where deduction is done and fails, or in
19523 contexts where deduction is not done, if a template argument list is
19524 specified and it, along with any default template arguments, identifies
19525 a single function template specialization, then the template-id is an
19526 lvalue for the function template specialization. */
19528 tree
19530 {
19543 {
19546 }
19548 {
19551 }
19553 {
19556 }
19559 {
19563 /* If we got some explicit template args, we need to plug them into
19564 the affected templates before we try to unify, in case the
19565 explicit args will completely resolve the templates in question. */
19573 {
19586 {
19589 {
19592 }
19594 {
19597 }
19598 }
19599 }
19601 {
19609 {
19610 tree base
19613 }
19617 }
19619 /* There were no good options and at least one bad one, so let the
19620 user know what the problem is. */
19622 }
19624 }
19626 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19627 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19628 different overloads deduce different arguments for a given parm.
19629 ADDR_P is true if the expression for which deduction is being
19630 performed was of the form "& fn" rather than simply "fn".
19632 Returns 1 on success. */
19634 static int
19636 tree orig_targs,
19637 tree targs,
19638 tree parm,
19639 tree arg,
19640 unification_kind_t strict,
19644 {
19646 tree tempargs;
19652 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19653 to function or pointer to member function argument if the set of
19654 overloaded functions does not contain function templates and at most
19655 one of a set of overloaded functions provides a unique match.
19657 So if this is a template, just return success. */
19669 /* We don't copy orig_targs for this because if we have already deduced
19670 some template args from previous args, unify would complain when we
19671 try to deduce a template parameter for the same argument, even though
19672 there isn't really a conflict. */
19679 /* First make sure we didn't deduce anything that conflicts with
19680 explicitly specified args. */
19682 {
19689 /* Since we're unifying against ourselves, we will fill in
19690 template args used in the function parm list with our own
19691 template parms. Discard them. */
19694 {
19695 /* Check that the argument at each index of the deduced argument pack
19696 is equivalent to the corresponding explicitly specified argument.
19697 We may have deduced more arguments than were explicitly specified,
19698 and that's OK. */
19700 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
19701 that's wrong if we deduce the same argument pack from multiple
19702 function arguments: it's only incomplete the first time. */
19715 }
19718 }
19721 {
19726 }
19729 }
19731 /* PARM is a template class (perhaps with unbound template
19732 parameters). ARG is a fully instantiated type. If ARG can be
19733 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
19734 TARGS are as for unify. */
19736 static tree
19739 {
19740 tree copy_of_targs;
19750 /* We need to make a new template argument vector for the call to
19751 unify. If we used TARGS, we'd clutter it up with the result of
19752 the attempted unification, even if this class didn't work out.
19753 We also don't want to commit ourselves to all the unifications
19754 we've already done, since unification is supposed to be done on
19755 an argument-by-argument basis. In other words, consider the
19756 following pathological case:
19758 template <int I, int J, int K>
19759 struct S {};
19761 template <int I, int J>
19762 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
19764 template <int I, int J, int K>
19765 void f(S<I, J, K>, S<I, I, I>);
19767 void g() {
19768 S<0, 0, 0> s0;
19769 S<0, 1, 2> s2;
19771 f(s0, s2);
19772 }
19774 Now, by the time we consider the unification involving `s2', we
19775 already know that we must have `f<0, 0, 0>'. But, even though
19776 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
19777 because there are two ways to unify base classes of S<0, 1, 2>
19778 with S<I, I, I>. If we kept the already deduced knowledge, we
19779 would reject the possibility I=1. */
19783 {
19787 }
19789 /* If unification failed, we're done. */
19795 }
19797 /* Given a template type PARM and a class type ARG, find the unique
19798 base type in ARG that is an instance of PARM. We do not examine
19799 ARG itself; only its base-classes. If there is not exactly one
19800 appropriate base class, return NULL_TREE. PARM may be the type of
19801 a partial specialization, as well as a plain template type. Used
19802 by unify. */
19804 static enum template_base_result
19807 {
19809 tree binfo;
19815 {
19816 /* The type could not be completed. */
19819 }
19821 /* Walk in inheritance graph order. The search order is not
19822 important, and this avoids multiple walks of virtual bases. */
19824 {
19829 {
19830 /* If there is more than one satisfactory baseclass, then:
19832 [temp.deduct.call]
19834 If they yield more than one possible deduced A, the type
19835 deduction fails.
19837 applies. */
19839 {
19842 }
19845 }
19846 }
19850 }
19852 /* Returns the level of DECL, which declares a template parameter. */
19854 static int
19856 {
19858 {
19868 }
19870 }
19872 /* Decide whether ARG can be unified with PARM, considering only the
19873 cv-qualifiers of each type, given STRICT as documented for unify.
19874 Returns nonzero iff the unification is OK on that basis. */
19876 static int
19878 {
19884 {
19885 /* Although a CVR qualifier is ignored when being applied to a
19886 substituted template parameter ([8.3.2]/1 for example), that
19887 does not allow us to unify "const T" with "int&" because both
19888 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
19889 It is ok when we're allowing additional CV qualifiers
19890 at the outer level [14.8.2.1]/3,1st bullet. */
19900 }
19911 }
19913 /* Determines the LEVEL and INDEX for the template parameter PARM. */
19914 void
19916 {
19920 {
19923 }
19924 else
19925 {
19928 }
19929 }
19931 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
19932 do { \
19933 if (unify (TP, TA, P, A, S, EP)) \
19934 return 1; \
19935 } while (0)
19937 /* Unifies the remaining arguments in PACKED_ARGS with the pack
19938 expansion at the end of PACKED_PARMS. Returns 0 if the type
19939 deduction succeeds, 1 otherwise. STRICT is the same as in
19940 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
19941 function call argument list. We'll need to adjust the arguments to make them
19942 types. SUBR tells us if this is from a recursive call to
19943 type_unification_real, or for comparing two template argument
19944 lists. */
19946 static int
19950 {
19951 tree parm
19961 /* Determine the parameter packs we will be deducing from the
19962 pattern, and record their current deductions. */
19965 {
19969 /* Determine the index and level of this parameter pack. */
19972 /* Keep track of the parameter packs and their corresponding
19973 argument packs. */
19976 }
19978 /* Loop through all of the arguments that have not yet been
19979 unified and unify each with the pattern. */
19981 {
19982 tree parm;
19986 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
19987 or the element of its argument pack at the current index if
19988 this argument was explicitly specified. */
19990 {
19999 {
20002 }
20004 }
20006 /* If we had explicit template arguments, substitute them into the
20007 pattern before deduction. */
20009 {
20010 /* Some arguments might still be unspecified or dependent. */
20018 NULL_TREE);
20023 }
20024 else
20027 /* Unify the pattern with the current argument. */
20029 explain_p))
20032 /* For each parameter pack, collect the deduced value. */
20034 {
20040 }
20041 }
20043 /* Verify that the results of unification with the parameter packs
20044 produce results consistent with what we've seen before, and make
20045 the deduced argument packs available. */
20047 {
20054 /* By default keep the original deduced argument pack.
20055 If necessary, more specific code is going to update the
20056 resulting deduced argument later down in this function. */
20060 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20061 actually deduce anything. */
20069 {
20070 /* If we had fewer function args than explicit template args,
20071 just use the explicits. */
20076 }
20079 {
20080 tree result;
20081 /* Build the deduced *_ARGUMENT_PACK. */
20083 {
20088 }
20089 else
20094 /* Note the deduced argument packs for this parameter
20095 pack. */
20097 }
20101 {
20102 /* We only had the explicitly-provided arguments before, but
20103 now we have a complete set of arguments. */
20109 }
20110 else
20111 {
20117 /* Inconsistent unification of this parameter pack. */
20119 bad_old_arg,
20120 bad_new_arg);
20121 }
20122 }
20125 }
20127 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20128 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20129 parameters and return value are as for unify. */
20131 static int
20135 {
20136 tree parm_max;
20137 tree arg_max;
20141 /* Our representation of array types uses "N - 1" as the
20142 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20143 not an integer constant. We cannot unify arbitrarily
20144 complex expressions, so we eliminate the MINUS_EXPRs
20145 here. */
20149 {
20152 }
20156 {
20157 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20158 trying to unify the type of a variable with the type
20159 of a template parameter. For example:
20161 template <unsigned int N>
20162 void f (char (&) [N]);
20163 int g();
20164 void h(int i) {
20165 char a[g(i)];
20166 f(a);
20167 }
20169 Here, the type of the ARG will be "int [g(i)]", and
20170 may be a SAVE_EXPR, etc. */
20174 }
20176 /* If only one of the bounds used a MINUS_EXPR, compensate
20177 by adding one to the other bound. */
20180 integer_type_node,
20181 parm_max,
20182 integer_one_node);
20185 integer_type_node,
20186 arg_max,
20187 integer_one_node);
20191 }
20193 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20197 static pa_kind_t
20199 {
20208 else
20210 }
20212 /* Deduce the value of template parameters. TPARMS is the (innermost)
20213 set of template parameters to a template. TARGS is the bindings
20214 for those template parameters, as determined thus far; TARGS may
20215 include template arguments for outer levels of template parameters
20216 as well. PARM is a parameter to a template function, or a
20217 subcomponent of that parameter; ARG is the corresponding argument.
20218 This function attempts to match PARM with ARG in a manner
20219 consistent with the existing assignments in TARGS. If more values
20220 are deduced, then TARGS is updated.
20222 Returns 0 if the type deduction succeeds, 1 otherwise. The
20223 parameter STRICT is a bitwise or of the following flags:
20225 UNIFY_ALLOW_NONE:
20226 Require an exact match between PARM and ARG.
20227 UNIFY_ALLOW_MORE_CV_QUAL:
20228 Allow the deduced ARG to be more cv-qualified (by qualification
20229 conversion) than ARG.
20230 UNIFY_ALLOW_LESS_CV_QUAL:
20231 Allow the deduced ARG to be less cv-qualified than ARG.
20232 UNIFY_ALLOW_DERIVED:
20233 Allow the deduced ARG to be a template base class of ARG,
20234 or a pointer to a template base class of the type pointed to by
20235 ARG.
20236 UNIFY_ALLOW_INTEGER:
20237 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20238 case for more information.
20239 UNIFY_ALLOW_OUTER_LEVEL:
20240 This is the outermost level of a deduction. Used to determine validity
20241 of qualification conversions. A valid qualification conversion must
20242 have const qualified pointers leading up to the inner type which
20243 requires additional CV quals, except at the outer level, where const
20244 is not required [conv.qual]. It would be normal to set this flag in
20245 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20246 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20247 This is the outermost level of a deduction, and PARM can be more CV
20248 qualified at this point.
20249 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20250 This is the outermost level of a deduction, and PARM can be less CV
20251 qualified at this point. */
20253 static int
20256 {
20258 tree targ;
20259 tree tparm;
20261 tsubst_flags_t complain = (explain_p
20262 ? tf_warning_or_error
20265 /* I don't think this will do the right thing with respect to types.
20266 But the only case I've seen it in so far has been array bounds, where
20267 signedness is the only information lost, and I think that will be
20268 okay. */
20276 /* We can't deduce anything from this, but we might get all the
20277 template args from other function args. */
20283 /* If PARM uses template parameters, then we can't bail out here,
20284 even if ARG == PARM, since we won't record unifications for the
20285 template parameters. We might need them if we're trying to
20286 figure out which of two things is more specialized. */
20290 /* Handle init lists early, so the rest of the function can assume
20291 we're dealing with a type. */
20293 {
20298 /* Replace T with std::initializer_list<T> for deduction. */
20305 /* We can only deduce from an initializer list argument if the
20306 parameter is std::initializer_list or an array; otherwise this
20307 is a non-deduced context. */
20312 else
20313 {
20315 /* Deduction is defined in terms of a single type, so just punt
20316 on the (bizarre) std::initializer_list<T...>. */
20319 }
20322 {
20329 {
20333 /* It should only be possible to get here for a call. */
20335 elt_strict |= maybe_adjust_types_for_deduction
20338 }
20341 explain_p);
20342 }
20346 {
20347 /* Also deduce from the length of the initializer list. */
20354 }
20356 /* If the std::initializer_list<T> deduction worked, replace the
20357 deduced A with std::initializer_list<A>. */
20359 {
20364 }
20366 }
20368 /* If parm and arg aren't the same kind of thing (template, type, or
20369 expression), fail early. */
20373 /* Immediately reject some pairs that won't unify because of
20374 cv-qualification mismatches. */
20377 /* It is the elements of the array which hold the cv quals of an array
20378 type, and the elements might be template type parms. We'll check
20379 when we recurse. */
20381 /* We check the cv-qualifiers when unifying with template type
20382 parameters below. We want to allow ARG `const T' to unify with
20383 PARM `T' for example, when computing which of two templates
20384 is more specialized, for example. */
20398 {
20402 /* In a type which contains a nested-name-specifier, template
20403 argument values cannot be deduced for template parameters used
20404 within the nested-name-specifier. */
20416 /* The PARM is not one we're trying to unify. Just check
20417 to see if it matches ARG. */
20418 {
20423 else
20425 }
20432 /* Check for mixed types and values. */
20440 {
20443 {
20444 /* First try to match ARG directly. */
20446 explain_p);
20448 {
20449 /* Otherwise, look for a suitable base of ARG, as below. */
20456 }
20457 }
20458 /* ARG must be constructed from a template class or a template
20459 template parameter. */
20464 /* Deduce arguments T, i from TT<T> or TT<i>. */
20470 /* Fall through to deduce template name. */
20471 }
20475 {
20476 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20478 /* Simple cases: Value already set, does match or doesn't. */
20483 }
20484 else
20485 {
20486 /* If PARM is `const T' and ARG is only `int', we don't have
20487 a match unless we are allowing additional qualification.
20488 If ARG is `const int' and PARM is just `T' that's OK;
20489 that binds `const int' to `T'. */
20494 /* Consider the case where ARG is `const volatile int' and
20495 PARM is `const T'. Then, T should be `volatile int'. */
20496 arg = cp_build_qualified_type_real
20501 /* Simple cases: Value already set, does match or doesn't. */
20507 /* Make sure that ARG is not a variable-sized array. (Note
20508 that were talking about variable-sized arrays (like
20509 `int[n]'), rather than arrays of unknown size (like
20510 `int[]').) We'll get very confused by such a type since
20511 the bound of the array is not constant, and therefore
20512 not mangleable. Besides, such types are not allowed in
20513 ISO C++, so we can do as we please here. We do allow
20514 them for 'auto' deduction, since that isn't ABI-exposed. */
20518 /* Strip typedefs as in convert_template_argument. */
20520 }
20522 /* If ARG is a parameter pack or an expansion, we cannot unify
20523 against it unless PARM is also a parameter pack. */
20528 /* If the argument deduction results is a METHOD_TYPE,
20529 then there is a problem.
20530 METHOD_TYPE doesn't map to any real C++ type the result of
20531 the deduction can not be of that type. */
20545 {
20546 /* The PARM is not one we're trying to unify. Just check
20547 to see if it matches ARG. */
20553 }
20559 {
20564 }
20567 /* We deduce from array bounds in try_array_deduction. */
20571 {
20576 }
20578 /* [temp.deduct.type] If, in the declaration of a function template
20579 with a non-type template-parameter, the non-type
20580 template-parameter is used in an expression in the function
20581 parameter-list and, if the corresponding template-argument is
20582 deduced, the template-argument type shall match the type of the
20583 template-parameter exactly, except that a template-argument
20584 deduced from an array bound may be of any integral type.
20585 The non-type parameter might use already deduced type parameters. */
20588 {
20592 }
20595 /* Template-parameter dependent expression. Just accept it for now.
20596 It will later be processed in convert_template_argument. */
20597 ;
20602 /* Convert the ARG to the type of PARM; the deduced non-type
20603 template argument must exactly match the types of the
20604 corresponding parameter. */
20607 /* We haven't deduced the type of this parameter yet. Try again
20608 later. */
20610 else
20613 /* If ARG is a parameter pack or an expansion, we cannot unify
20614 against it unless PARM is also a parameter pack. */
20619 {
20622 }
20627 {
20628 /* A pointer-to-member constant can be unified only with
20629 another constant. */
20633 /* Just unify the class member. It would be useless (and possibly
20634 wrong, depending on the strict flags) to unify also
20635 PTRMEM_CST_CLASS, because we want to be sure that both parm and
20636 arg refer to the same variable, even if through different
20637 classes. For instance:
20639 struct A { int x; };
20640 struct B : A { };
20642 Unification of &A::x and &B::x must succeed. */
20645 }
20648 {
20652 /* [temp.deduct.call]
20654 A can be another pointer or pointer to member type that can
20655 be converted to the deduced A via a qualification
20656 conversion (_conv.qual_).
20658 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
20659 This will allow for additional cv-qualification of the
20660 pointed-to types if appropriate. */
20663 /* The derived-to-base conversion only persists through one
20664 level of pointers. */
20669 }
20701 /* We have already checked cv-qualification at the top of the
20702 function. */
20706 /* As far as unification is concerned, this wins. Later checks
20707 will invalidate it if necessary. */
20710 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
20711 /* Type INTEGER_CST can come from ordinary constant template args. */
20723 {
20733 /* Check for pack expansions in the parameters. */
20735 {
20737 {
20739 /* We can unify against something with a trailing
20740 parameter pack. */
20742 else
20743 /* [temp.deduct.type]/9: If the template argument list of
20744 P contains a pack expansion that is not the last
20745 template argument, the entire template argument list
20746 is a non-deduced context. */
20748 }
20749 }
20751 /* If we don't have enough arguments to satisfy the parameters
20752 (not counting the pack expression at the end), or we have
20753 too many arguments for a parameter list that doesn't end in
20754 a pack expression, we can't unify. */
20760 /* Unify all of the parameters that precede the (optional)
20761 pack expression. */
20763 {
20768 }
20771 DEDUCE_EXACT,
20774 }
20782 {
20790 }
20795 {
20799 {
20800 /* First, we try to unify the PARM and ARG directly. */
20805 {
20806 /* Fallback to the special case allowed in
20807 [temp.deduct.call]:
20809 If P is a class, and P has the form
20810 template-id, then A can be a derived class of
20811 the deduced A. Likewise, if P is a pointer to
20812 a class of the form template-id, A can be a
20813 pointer to a derived class pointed to by the
20814 deduced A. */
20820 {
20821 /* Don't give the derived diagnostic if we're
20822 already dealing with the same template. */
20823 bool same_template
20829 }
20830 }
20831 }
20835 /* Perhaps PARM is something like S<U> and ARG is S<int>.
20836 Then, we should unify `int' and `U'. */
20838 else
20839 /* There's no chance of unification succeeding. */
20844 }
20851 {
20854 tree a;
20860 /* CV qualifications for methods can never be deduced, they must
20861 match exactly. We need to check them explicitly here,
20862 because type_unification_real treats them as any other
20863 cv-qualified parameter. */
20865 && (!check_cv_quals_for_unify
20893 {
20905 }
20908 }
20911 /* Unify a pointer to member with a pointer to member function, which
20912 deduces the type of the member as a function type. */
20914 {
20915 /* Check top-level cv qualifiers */
20923 /* Determine the type of the function we are unifying against. */
20927 }
20946 /* Matched cases are handled by the ARG == PARM test above. */
20950 /* We might get a variable as a non-type template argument in parm if the
20951 corresponding parameter is type-dependent. Make any necessary
20952 adjustments based on whether arg is a reference. */
20956 {
20961 }
20962 /* Now use the normal expression code to check whether they match. */
20973 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
20974 or UNDERLYING_TYPE nodes. */
20978 /* Unification fails if we hit an error node. */
20983 {
20993 }
20994 /* FALLTHRU */
20997 /* An unresolved overload is a nondeduced context. */
21001 expr:
21002 /* We must be looking at an expression. This can happen with
21003 something like:
21005 template <int I>
21006 void foo(S<I>, S<I + 2>);
21008 This is a "nondeduced context":
21010 [deduct.type]
21012 The nondeduced contexts are:
21014 --A type that is a template-id in which one or more of
21015 the template-arguments is an expression that references
21016 a template-parameter.
21018 In these cases, we assume deduction succeeded, but don't
21019 actually infer any unifications. */
21024 else
21026 }
21027 }
21028 #undef RECUR_AND_CHECK_FAILURE
21029 \f
21030 /* Note that DECL can be defined in this translation unit, if
21031 required. */
21033 static void
21035 {
21036 tree clone;
21040 }
21042 /* Called if RESULT is explicitly instantiated, or is a member of an
21043 explicitly instantiated class. */
21045 void
21047 {
21050 /* If this entity has already been written out, it's too late to
21051 make any modifications. */
21055 /* For anonymous namespace we don't need to do anything. */
21057 {
21060 }
21063 /* The TREE_PUBLIC flag for function declarations will have been
21064 set correctly by tsubst. */
21067 /* This might have been set by an earlier implicit instantiation. */
21072 else
21073 {
21076 /* Always make artificials weak. */
21079 /* For WIN32 we also want to put explicit instantiations in
21080 linkonce sections. */
21083 }
21085 /* If EXTERN_P, then this function will not be emitted -- unless
21086 followed by an explicit instantiation, at which point its linkage
21087 will be adjusted. If !EXTERN_P, then this function will be
21088 emitted here. In neither circumstance do we want
21089 import_export_decl to adjust the linkage. */
21091 }
21093 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21094 important template arguments. If any are missing, we check whether
21095 they're important by using error_mark_node for substituting into any
21096 args that were used for partial ordering (the ones between ARGS and END)
21097 and seeing if it bubbles up. */
21099 static bool
21101 {
21106 {
21109 }
21111 {
21115 }
21117 }
21119 /* Given two function templates PAT1 and PAT2, return:
21121 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21122 -1 if PAT2 is more specialized than PAT1.
21123 0 if neither is more specialized.
21125 LEN indicates the number of parameters we should consider
21126 (defaulted parameters should not be considered).
21128 The 1998 std underspecified function template partial ordering, and
21129 DR214 addresses the issue. We take pairs of arguments, one from
21130 each of the templates, and deduce them against each other. One of
21131 the templates will be more specialized if all the *other*
21132 template's arguments deduce against its arguments and at least one
21133 of its arguments *does* *not* deduce against the other template's
21134 corresponding argument. Deduction is done as for class templates.
21135 The arguments used in deduction have reference and top level cv
21136 qualifiers removed. Iff both arguments were originally reference
21137 types *and* deduction succeeds in both directions, an lvalue reference
21138 wins against an rvalue reference and otherwise the template
21139 with the more cv-qualified argument wins for that pairing (if
21140 neither is more cv-qualified, they both are equal). Unlike regular
21141 deduction, after all the arguments have been deduced in this way,
21142 we do *not* verify the deduced template argument values can be
21143 substituted into non-deduced contexts.
21145 The logic can be a bit confusing here, because we look at deduce1 and
21146 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21147 can find template arguments for pat1 to make arg1 look like arg2, that
21148 means that arg2 is at least as specialized as arg1. */
21150 int
21152 {
21165 /* Remove the this parameter from non-static member functions. If
21166 one is a non-static member function and the other is not a static
21167 member function, remove the first parameter from that function
21168 also. This situation occurs for operator functions where we
21169 locate both a member function (with this pointer) and non-member
21170 operator (with explicit first operand). */
21172 {
21177 }
21179 {
21182 {
21183 len--;
21185 }
21186 }
21188 /* If only one is a conversion operator, they are unordered. */
21192 /* Consider the return type for a conversion function */
21194 {
21197 len++;
21198 }
21200 processing_template_decl++;
21206 /* Stop when an ellipsis is seen. */
21208 {
21219 {
21220 /* When both arguments are pack expansions, we need only
21221 unify the patterns themselves. */
21225 /* This is the last comparison we need to do. */
21227 }
21230 {
21234 }
21237 {
21241 }
21247 {
21253 /* Setup the parameter vector, which contains only ARG1. */
21256 /* Setup the argument vector, which contains the remaining
21257 arguments. */
21266 /* We cannot deduce in the other direction, because ARG1 is
21267 a pack expansion but ARG2 is not. */
21269 }
21271 {
21277 /* Setup the parameter vector, which contains only ARG1. */
21280 /* Setup the argument vector, which contains the remaining
21281 arguments. */
21290 /* We cannot deduce in the other direction, because ARG2 is
21291 a pack expansion but ARG1 is not.*/
21293 }
21295 else
21296 {
21297 /* The normal case, where neither argument is a pack
21298 expansion. */
21305 }
21307 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21308 arg2, then arg2 is not as specialized as arg1. */
21314 /* "If, for a given type, deduction succeeds in both directions
21315 (i.e., the types are identical after the transformations above)
21316 and both P and A were reference types (before being replaced with
21317 the type referred to above):
21318 - if the type from the argument template was an lvalue reference and
21319 the type from the parameter template was not, the argument type is
21320 considered to be more specialized than the other; otherwise,
21321 - if the type from the argument template is more cv-qualified
21322 than the type from the parameter template (as described above),
21323 the argument type is considered to be more specialized than the other;
21324 otherwise,
21325 - neither type is more specialized than the other." */
21328 {
21330 {
21333 else
21335 }
21337 {
21342 }
21343 }
21346 /* We've failed to deduce something in either direction.
21347 These must be unordered. */
21352 /* We have already processed all of the arguments in our
21353 handing of the pack expansion type. */
21358 }
21360 /* "In most cases, all template parameters must have values in order for
21361 deduction to succeed, but for partial ordering purposes a template
21362 parameter may remain without a value provided it is not used in the
21363 types being used for partial ordering."
21365 Thus, if we are missing any of the targs1 we need to substitute into
21366 origs1, then pat2 is not as specialized as pat1. This can happen when
21367 there is a nondeduced context. */
21373 processing_template_decl--;
21375 /* If both deductions succeed, the partial ordering selects the more
21376 constrained template. */
21378 {
21383 }
21385 /* All things being equal, if the next argument is a pack expansion
21386 for one function but not for the other, prefer the
21387 non-variadic function. FIXME this is bogus; see c++/41958. */
21391 {
21394 }
21400 else
21402 }
21404 /* Determine which of two partial specializations of TMPL is more
21405 specialized.
21407 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21408 to the first partial specialization. The TREE_PURPOSE is the
21409 innermost set of template parameters for the partial
21410 specialization. PAT2 is similar, but for the second template.
21412 Return 1 if the first partial specialization is more specialized;
21413 -1 if the second is more specialized; 0 if neither is more
21414 specialized.
21416 See [temp.class.order] for information about determining which of
21417 two templates is more specialized. */
21419 static int
21421 {
21422 tree targs;
21431 /* Just like what happens for functions, if we are ordering between
21432 different template specializations, we may encounter dependent
21433 types in the arguments, and we need our dependency check functions
21434 to behave correctly. */
21438 {
21441 }
21445 {
21448 }
21451 /* If both deductions succeed, the partial ordering selects the more
21452 constrained template. */
21456 /* In the case of a tie where at least one of the templates
21457 has a parameter pack at the end, the template with the most
21458 non-packed parameters wins. */
21460 && any_deductions
21463 {
21469 /* We don't count the pack expansion at the end. */
21479 }
21482 }
21484 /* Return the template arguments that will produce the function signature
21485 DECL from the function template FN, with the explicit template
21486 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21487 also match. Return NULL_TREE if no satisfactory arguments could be
21488 found. */
21490 static tree
21492 {
21496 tree decl_arg_types;
21499 tree arg;
21503 /* Never do unification on the 'this' parameter. */
21524 }
21526 /* Return the innermost template arguments that, when applied to a partial
21527 specialization SPEC_TMPL of TMPL, yield the ARGS.
21529 For example, suppose we have:
21531 template <class T, class U> struct S {};
21532 template <class T> struct S<T*, int> {};
21534 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21535 partial specialization and the ARGS will be {double*, int}. The resulting
21536 vector will be {double}, indicating that `T' is bound to `double'. */
21538 static tree
21540 {
21542 tree spec_args
21545 tree deduced_args;
21546 tree innermost_deduced_args;
21550 {
21554 innermost_deduced_args);
21555 }
21556 else
21560 again:
21569 {
21571 {
21577 }
21579 }
21583 {
21586 }
21588 /* Verify that nondeduced template arguments agree with the type
21589 obtained from argument deduction.
21591 For example:
21593 struct A { typedef int X; };
21594 template <class T, class U> struct C {};
21595 template <class T> struct C<T, typename T::X> {};
21597 Then with the instantiation `C<A, int>', we can deduce that
21598 `T' is `A' but unify () does not check whether `typename T::X'
21599 is `int'. */
21608 /* We only need to check the innermost arguments; the other
21609 arguments will always agree. */
21614 /* Now that we have bindings for all of the template arguments,
21615 ensure that the arguments deduced for the template template
21616 parameters have compatible template parameter lists. See the use
21617 of template_template_parm_bindings_ok_p in fn_type_unification
21618 for more information. */
21623 }
21625 // Compare two function templates T1 and T2 by deducing bindings
21626 // from one against the other. If both deductions succeed, compare
21627 // constraints to see which is more constrained.
21628 static int
21630 {
21635 {
21638 }
21641 {
21644 }
21646 // If both deductions succeed, then one may be more constrained.
21651 }
21653 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
21654 Return the TREE_LIST node with the most specialized template, if
21655 any. If there is no most specialized template, the error_mark_node
21656 is returned.
21658 Note that this function does not look at, or modify, the
21659 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
21660 returned is one of the elements of INSTANTIATIONS, callers may
21661 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
21662 and retrieve it from the value returned. */
21664 tree
21666 {
21673 {
21678 {
21679 /* Equally specialized, move to next function. If there
21680 is no next function, nothing's most specialized. */
21685 }
21686 }
21689 /* Now verify that champ is better than everything earlier in the
21690 instantiation list. */
21693 {
21696 }
21697 }
21699 processing_template_decl--;
21705 }
21707 /* If DECL is a specialization of some template, return the most
21708 general such template. Otherwise, returns NULL_TREE.
21710 For example, given:
21712 template <class T> struct S { template <class U> void f(U); };
21714 if TMPL is `template <class U> void S<int>::f(U)' this will return
21715 the full template. This function will not trace past partial
21716 specializations, however. For example, given in addition:
21718 template <class T> struct S<T*> { template <class U> void f(U); };
21720 if TMPL is `template <class U> void S<int*>::f(U)' this will return
21721 `template <class T> template <class U> S<T*>::f(U)'. */
21723 tree
21725 {
21727 {
21730 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
21731 template friend, or a FIELD_DECL for a capture pack. */
21734 }
21736 /* Look for more and more general templates. */
21738 {
21739 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
21740 (See cp-tree.h for details.) */
21749 /* Stop if we run into an explicitly specialized class template. */
21756 }
21759 }
21761 /* Return the most specialized of the template partial specializations
21762 which can produce TARGET, a specialization of some class or variable
21763 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
21764 a TEMPLATE_DECL node corresponding to the partial specialization, while
21765 the TREE_PURPOSE is the set of template arguments that must be
21766 substituted into the template pattern in order to generate TARGET.
21768 If the choice of partial specialization is ambiguous, a diagnostic
21769 is issued, and the error_mark_node is returned. If there are no
21770 partial specializations matching TARGET, then NULL_TREE is
21771 returned, indicating that the primary template should be used. */
21773 static tree
21775 {
21777 tree t;
21778 tree champ;
21785 {
21789 }
21791 {
21794 }
21796 {
21800 }
21801 else
21806 /* For determining which partial specialization to use, only the
21807 innermost args are interesting. */
21809 {
21812 }
21815 {
21816 tree spec_args;
21820 {
21821 /* Substitute in the template args from the enclosing class. */
21825 }
21832 {
21836 /* Keep the candidate only if the constraints are satisfied,
21837 or if we're not compiling with concepts. */
21840 {
21843 }
21844 }
21845 }
21855 {
21858 ;
21859 else
21860 {
21862 {
21865 {
21868 }
21869 }
21871 }
21872 }
21876 {
21879 {
21882 }
21883 }
21886 {
21893 else
21897 {
21902 }
21905 }
21908 }
21910 /* Explicitly instantiate DECL. */
21912 void
21914 {
21919 /* An error occurred, for which grokdeclarator has already issued
21920 an appropriate message. */
21923 {
21926 }
21932 {
21933 /* There is an asymmetry here in the way VAR_DECLs and
21934 FUNCTION_DECLs are handled by grokdeclarator. In the case of
21935 the latter, the DECL we get back will be marked as a
21936 template instantiation, and the appropriate
21937 DECL_TEMPLATE_INFO will be set up. This does not happen for
21938 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
21939 should handle VAR_DECLs as it currently handles
21940 FUNCTION_DECLs. */
21942 {
21945 }
21948 {
21951 }
21953 {
21958 }
21959 }
21961 {
21964 }
21965 else
21968 /* Check for various error cases. Note that if the explicit
21969 instantiation is valid the RESULT will currently be marked as an
21970 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
21971 until we get here. */
21974 {
21975 /* DR 259 [temp.spec].
21977 Both an explicit instantiation and a declaration of an explicit
21978 specialization shall not appear in a program unless the explicit
21979 instantiation follows a declaration of the explicit specialization.
21981 For a given set of template parameters, if an explicit
21982 instantiation of a template appears after a declaration of an
21983 explicit specialization for that template, the explicit
21984 instantiation has no effect. */
21986 }
21988 {
21989 /* [temp.spec]
21991 No program shall explicitly instantiate any template more
21992 than once.
21994 We check DECL_NOT_REALLY_EXTERN so as not to complain when
21995 the first instantiation was `extern' and the second is not,
21996 and EXTERN_P for the opposite case. */
21999 /* If an "extern" explicit instantiation follows an ordinary
22000 explicit instantiation, the template is instantiated. */
22003 }
22005 {
22008 }
22010 {
22013 }
22016 ;
22018 {
22021 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22024 }
22025 else
22033 }
22035 static void
22037 {
22043 {
22046 }
22047 }
22049 /* Called from do_type_instantiation through binding_table_foreach to
22050 do recursive instantiation for the type bound in ENTRY. */
22051 static void
22053 {
22059 }
22061 /* Called from do_type_instantiation to instantiate a member
22062 (a member function or a static member variable) of an
22063 explicitly instantiated class template. */
22064 static void
22066 {
22071 }
22073 /* Perform an explicit instantiation of template class T. STORAGE, if
22074 non-null, is the RID for extern, inline or static. COMPLAIN is
22075 nonzero if this is called from the parser, zero if called recursively,
22076 since the standard is unclear (as detailed below). */
22078 void
22080 {
22090 {
22091 tree tmpl =
22095 else
22098 }
22103 {
22106 t);
22108 }
22111 {
22113 {
22115 {
22118 "ISO C++ 1998 forbids the use of %<extern%> on "
22120 }
22121 else
22123 "ISO C++ forbids the use of %qE"
22125 }
22133 else
22134 {
22136 storage);
22138 }
22139 }
22142 {
22143 /* DR 259 [temp.spec].
22145 Both an explicit instantiation and a declaration of an explicit
22146 specialization shall not appear in a program unless the explicit
22147 instantiation follows a declaration of the explicit specialization.
22149 For a given set of template parameters, if an explicit
22150 instantiation of a template appears after a declaration of an
22151 explicit specialization for that template, the explicit
22152 instantiation has no effect. */
22154 }
22156 {
22157 /* [temp.spec]
22159 No program shall explicitly instantiate any template more
22160 than once.
22162 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22163 instantiation was `extern'. If EXTERN_P then the second is.
22164 These cases are OK. */
22171 /* If we've already instantiated the template, just return now. */
22174 }
22182 {
22183 tree tmp;
22185 /* In contrast to implicit instantiation, where only the
22186 declarations, and not the definitions, of members are
22187 instantiated, we have here:
22189 [temp.explicit]
22191 The explicit instantiation of a class template specialization
22192 implies the instantiation of all of its members not
22193 previously explicitly specialized in the translation unit
22194 containing the explicit instantiation.
22196 Of course, we can't instantiate member template classes, since
22197 we don't have any arguments for them. Note that the standard
22198 is unclear on whether the instantiation of the members are
22199 *explicit* instantiations or not. However, the most natural
22200 interpretation is that it should be an explicit instantiation. */
22216 }
22217 }
22219 /* Given a function DECL, which is a specialization of TMPL, modify
22220 DECL to be a re-instantiation of TMPL with the same template
22221 arguments. TMPL should be the template into which tsubst'ing
22222 should occur for DECL, not the most general template.
22224 One reason for doing this is a scenario like this:
22226 template <class T>
22227 void f(const T&, int i);
22229 void g() { f(3, 7); }
22231 template <class T>
22232 void f(const T& t, const int i) { }
22234 Note that when the template is first instantiated, with
22235 instantiate_template, the resulting DECL will have no name for the
22236 first parameter, and the wrong type for the second. So, when we go
22237 to instantiate the DECL, we regenerate it. */
22239 static void
22241 {
22242 /* The arguments used to instantiate DECL, from the most general
22243 template. */
22244 tree code_pattern;
22248 /* Make sure that we can see identifiers, and compute access
22249 correctly. */
22253 {
22254 tree decl_parm;
22255 tree pattern_parm;
22256 tree specs;
22270 specs);
22272 /* Merge parameter declarations. */
22275 pattern_parm
22279 {
22280 tree parm_type;
22281 tree attributes;
22286 NULL_TREE);
22292 {
22295 }
22298 }
22299 /* Merge any parameters that match with the function parameter
22300 pack. */
22302 {
22304 tree expanded_types;
22305 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22306 the parameters in this function parameter pack. */
22311 {
22312 tree parm_type;
22313 tree attributes;
22316 /* Rename the parameter to include the index. */
22325 {
22328 }
22330 }
22331 }
22332 /* Merge additional specifiers from the CODE_PATTERN. */
22336 }
22338 {
22346 }
22347 else
22351 }
22353 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22354 substituted to get DECL. */
22356 tree
22358 {
22361 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22362 for the instantiation. This is not always the most general
22363 template. Consider, for example:
22365 template <class T>
22366 struct S { template <class U> void f();
22367 template <> void f<int>(); };
22369 and an instantiation of S<double>::f<int>. We want TD to be the
22370 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22372 more general template. */
22374 /* We must also deal with friend templates. Given:
22376 template <class T> struct S {
22377 template <class U> friend void f() {};
22378 };
22380 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22381 so far as the language is concerned, but that's still
22382 where we get the pattern for the instantiation from. On
22383 other hand, if the definition comes outside the class, say:
22385 template <class T> struct S {
22386 template <class U> friend void f();
22387 };
22388 template <class U> friend void f() {}
22390 we don't need to look any further. That's what the check for
22391 DECL_INITIAL is for. */
22395 {
22396 /* The present template, TD, should not be a definition. If it
22397 were a definition, we should be using it! Note that we
22398 cannot restructure the loop to just keep going until we find
22399 a template with a definition, since that might go too far if
22400 a specialization was declared, but not defined. */
22402 /* Fetch the more general template. */
22404 }
22407 }
22409 /* Returns true if we need to instantiate this template instance even if we
22410 know we aren't going to emit it. */
22412 bool
22414 {
22415 /* We always instantiate inline functions so that we can inline them. An
22416 explicit instantiation declaration prohibits implicit instantiation of
22417 non-inline functions. With high levels of optimization, we would
22418 normally inline non-inline functions -- but we're not allowed to do
22419 that for "extern template" functions. Therefore, we check
22420 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22424 /* And we need to instantiate static data members so that
22425 their initializers are available in integral constant
22426 expressions. */
22429 }
22431 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22432 instantiate it now, modifying TREE_TYPE (fn). */
22434 void
22436 {
22439 /* Don't instantiate a noexcept-specification from template context. */
22454 {
22458 {
22473 }
22474 else
22478 }
22481 {
22484 else
22486 }
22487 }
22489 /* Produce the definition of D, a _DECL generated from a template. If
22490 DEFER_OK is true, then we don't have to actually do the
22491 instantiation now; we just have to do it sometime. Normally it is
22492 an error if this is an explicit instantiation but D is undefined.
22493 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22494 instantiated class template. */
22496 tree
22498 {
22500 tree gen_args;
22501 tree args;
22502 tree td;
22503 tree code_pattern;
22504 tree spec;
22505 tree gen_tmpl;
22513 /* This function should only be used to instantiate templates for
22514 functions and static member variables. */
22517 /* A concept is never instantiated. */
22520 /* Variables are never deferred; if instantiation is required, they
22521 are instantiated right away. That allows for better code in the
22522 case that an expression refers to the value of the variable --
22523 if the variable has a constant value the referring expression can
22524 take advantage of that fact. */
22528 /* Don't instantiate cloned functions. Instead, instantiate the
22529 functions they cloned. */
22537 /* D has already been instantiated or explicitly specialized, so
22538 there's nothing for us to do here.
22540 It might seem reasonable to check whether or not D is an explicit
22541 instantiation, and, if so, stop here. But when an explicit
22542 instantiation is deferred until the end of the compilation,
22543 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22544 the instantiation. */
22547 /* Check to see whether we know that this template will be
22548 instantiated in some other file, as with "extern template"
22549 extension. */
22552 /* In general, we do not instantiate such templates. */
22560 /* We should already have the extra args. */
22563 /* And what's in the hash table should match D. */
22567 /* This needs to happen before any tsubsting. */
22573 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
22574 for the instantiation. */
22579 {
22580 /* Look up an explicit specialization, if any. */
22584 {
22587 }
22588 }
22592 /* We should never be trying to instantiate a member of a class
22593 template or partial specialization. */
22598 /* In the case of a friend template whose definition is provided
22599 outside the class, we may have too many arguments. Drop the
22600 ones we don't need. The same is true for specializations. */
22601 args = get_innermost_template_args
22605 {
22611 }
22612 else
22613 {
22618 else
22620 }
22622 /* We may be in the middle of deferred access check. Disable it now. */
22625 /* Unless an explicit instantiation directive has already determined
22626 the linkage of D, remember that a definition is available for
22627 this entity. */
22637 /* If D is a member of an explicitly instantiated class template,
22638 and no definition is available, treat it like an implicit
22639 instantiation. */
22642 {
22643 /* Leave linkage flags alone on instantiations with anonymous
22644 visibility. */
22646 {
22649 }
22651 }
22653 /* Defer all other templates, unless we have been explicitly
22654 forbidden from doing so. */
22656 template. */
22657 ! pattern_defined
22658 /* If it's OK to postpone instantiation, do so. */
22659 || defer_ok
22660 /* If this is a static data member that will be defined
22661 elsewhere, we don't want to instantiate the entire data
22662 member, but we do want to instantiate the initializer so that
22663 we can substitute that elsewhere. */
22665 /* Handle here a deleted function too, avoid generating
22666 its body (c++/61080). */
22668 {
22669 /* The definition of the static data member is now required so
22670 we must substitute the initializer. */
22674 {
22675 tree ns;
22676 tree init;
22685 args,
22688 /* If instantiating the initializer involved instantiating this
22689 again, don't call cp_finish_decl twice. */
22691 {
22692 /* Make sure the initializer is still constant, in case of
22693 circular dependency (template/instantiate6.C). */
22694 const_init
22698 LOOKUP_ONLYCONVERTING);
22699 }
22703 }
22705 /* We restore the source position here because it's used by
22706 add_pending_template. */
22712 /* [temp.explicit]
22714 The definition of a non-exported function template, a
22715 non-exported member function template, or a non-exported
22716 member function or static data member of a class template
22717 shall be present in every translation unit in which it is
22718 explicitly instantiated. */
22722 /* If we're in unevaluated context, we just wanted to get the
22723 constant value; this isn't an odr use, so don't queue
22724 a full instantiation. */
22727 /* ??? Historically, we have instantiated inline functions, even
22728 when marked as "extern template". */
22732 }
22733 /* Tell the repository that D is available in this translation unit
22734 -- and see if it is supposed to be instantiated here. */
22736 {
22737 /* In a PCH file, despite the fact that the repository hasn't
22738 requested instantiation in the PCH it is still possible that
22739 an instantiation will be required in a file that includes the
22740 PCH. */
22743 /* Instantiate inline functions so that the inliner can do its
22744 job, even though we'll not be emitting a copy of this
22745 function. */
22748 }
22751 tree fn_context;
22762 else
22763 {
22767 }
22769 /* Mark D as instantiated so that recursive calls to
22770 instantiate_decl do not try to instantiate it again. */
22773 /* Regenerate the declaration in case the template has been modified
22774 by a subsequent redeclaration. */
22777 /* We already set the file and line above. Reset them now in case
22778 they changed as a result of calling regenerate_decl_from_template. */
22782 {
22783 tree init;
22786 /* Clear out DECL_RTL; whatever was there before may not be right
22787 since we've reset the type of the declaration. */
22791 /* The initializer is placed in DECL_INITIAL by
22792 regenerate_decl_from_template so we don't need to
22793 push/pop_access_scope again here. Pull it out so that
22794 cp_finish_decl can process it. */
22799 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
22800 initializer. That function will defer actual emission until
22801 we have a chance to determine linkage. */
22804 /* Enter the scope of D so that access-checking works correctly. */
22817 }
22821 {
22823 tree tmpl_parm;
22824 tree spec_parm;
22828 /* Save away the current list, in case we are instantiating one
22829 template from within the body of another. */
22832 /* Set up the list of local specializations. */
22835 /* Set up context. */
22839 else
22840 {
22842 {
22843 /* When instantiating a lambda's templated function
22844 operator, we need to push the non-lambda class scope
22845 of the lambda itself so that the nested function
22846 stack is sufficiently correct to deal with this
22847 capture. */
22849 do
22854 }
22856 }
22858 /* Some typedefs referenced from within the template code need to be
22859 access checked at template instantiation time, i.e now. These
22860 types were added to the template at parsing time. Let's get those
22861 and perform the access checks then. */
22863 args);
22865 /* Create substitution entries for the parameters. */
22869 {
22873 }
22875 {
22877 {
22880 }
22881 else
22882 {
22883 /* Register the (value) argument pack as a specialization of
22884 TMPL_PARM, then move on. */
22887 }
22888 }
22891 /* Substitute into the body of the function. */
22895 else
22896 {
22901 /* Set the current input_location to the end of the function
22902 so that finish_function knows where we are. */
22903 input_location
22906 /* Remember if we saw an infinite loop in the template. */
22907 current_function_infinite_loop
22909 }
22911 /* We don't need the local specializations any more. */
22915 /* Finish the function. */
22919 else
22920 {
22923 }
22929 }
22931 /* We're not deferring instantiation any more. */
22936 else
22942 out:
22951 }
22953 /* Run through the list of templates that we wish we could
22954 instantiate, and instantiate any we can. RETRIES is the
22955 number of times we retry pending template instantiation. */
22957 void
22959 {
22963 /* Instantiating templates may trigger vtable generation. This in turn
22964 may require further template instantiations. We place a limit here
22965 to avoid infinite loop. */
22967 {
22971 "template instantiation depth exceeds maximum of %d"
22972 " instantiating %q+D, possibly from virtual table generation"
22976 /* Pretend that we defined it. */
22979 }
22981 do
22982 {
22987 {
22992 {
22993 tree fn;
22996 {
23000 fn;
23008 }
23011 }
23012 else
23013 {
23016 {
23017 instantiation
23023 }
23027 }
23030 /* If INSTANTIATION has been instantiated, then we don't
23031 need to consider it again in the future. */
23033 else
23034 {
23037 }
23040 }
23042 }
23046 }
23048 /* Substitute ARGVEC into T, which is a list of initializers for
23049 either base class or a non-static data member. The TREE_PURPOSEs
23050 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23051 instantiate_decl. */
23053 static tree
23055 {
23059 {
23060 tree decl;
23061 tree init;
23067 {
23068 tree expr;
23069 tree arg;
23071 /* Expand the base class expansion type into separate base
23072 classes. */
23074 tf_warning_or_error,
23075 NULL_TREE);
23079 /* We'll be building separate TREE_LISTs of arguments for
23080 each base. */
23086 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23087 expand each argument in the TREE_VALUE of t. */
23094 /* VOID_TYPE_NODE is used to indicate
23095 value-initialization. */
23096 {
23099 }
23100 else
23101 {
23102 /* Substitute parameter packs into each argument in the
23103 TREE_LIST. */
23106 {
23107 tree expanded_exprs;
23109 /* Expand the argument. */
23111 expanded_exprs
23113 tf_warning_or_error,
23114 NULL_TREE);
23118 /* Prepend each of the expanded expressions to the
23119 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23121 {
23126 }
23127 }
23130 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23131 since we built them backwards. */
23133 {
23136 }
23137 }
23138 }
23141 {
23143 {
23147 }
23148 else
23149 {
23150 tree tmp;
23165 /* If we had an initializer but it instantiated to nothing,
23166 value-initialize the object. This will only occur when
23167 the initializer was a pack expansion where the parameter
23168 packs used in that expansion were of length zero. */
23171 }
23174 {
23178 }
23179 }
23180 }
23182 }
23184 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23186 static void
23188 {
23193 else
23195 }
23197 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23198 is the instantiation (which should have been created with
23199 start_enum) and ARGS are the template arguments to use. */
23201 static void
23203 {
23204 tree e;
23210 {
23211 tree value;
23212 tree decl;
23215 /* Note that in a template enum, the TREE_VALUE is the
23216 CONST_DECL, not the corresponding INTEGER_CST. */
23221 /* Give this enumeration constant the correct access. */
23224 /* Actually build the enumerator itself. Here we're assuming that
23225 enumerators can't have dependent attributes. */
23228 }
23238 }
23240 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23241 its type -- but without substituting the innermost set of template
23242 arguments. So, innermost set of template parameters will appear in
23243 the type. */
23245 tree
23247 {
23248 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23250 }
23252 /* Return truthvalue if we're processing a template different from
23253 the last one involved in diagnostics. */
23254 bool
23256 {
23258 }
23260 /* Remember current template involved in diagnostics. */
23261 void
23263 {
23265 }
23269 {
23271 }
23273 /* Return TRUE if current_function_decl is being instantiated, false
23274 otherwise. */
23276 bool
23278 {
23281 }
23283 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23284 type. Return zero for ok, nonzero for disallowed. Issue error and
23285 warning messages under control of COMPLAIN. */
23287 static int
23289 {
23304 /* A bound template template parm could later be instantiated to have a valid
23305 nontype parm type via an alias template. */
23311 {
23314 else
23316 type);
23317 }
23319 }
23321 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23322 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23324 static bool
23326 {
23327 tree scope;
23329 /* [temp.dep.type]
23331 A type is dependent if it is:
23333 -- a template parameter. Template template parameters are types
23334 for us (since TYPE_P holds true for them) so we handle
23335 them here. */
23339 /* -- a qualified-id with a nested-name-specifier which contains a
23340 class-name that names a dependent type or whose unqualified-id
23341 names a dependent type. */
23345 /* An alias template specialization can be dependent even if the
23346 resulting type is not. */
23350 /* -- a cv-qualified type where the cv-unqualified type is
23351 dependent.
23352 No code is necessary for this bullet; the code below handles
23353 cv-qualified types, and we don't want to strip aliases with
23354 TYPE_MAIN_VARIANT because of DR 1558. */
23355 /* -- a compound type constructed from any dependent type. */
23365 {
23366 tree arg_type;
23371 arg_type;
23376 }
23377 /* -- an array type constructed from any dependent type or whose
23378 size is specified by a constant expression that is
23379 value-dependent.
23381 We checked for type- and value-dependence of the bounds in
23382 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23384 {
23389 }
23391 /* -- a template-id in which either the template name is a template
23392 parameter ... */
23395 /* ... or any of the template arguments is a dependent type or
23396 an expression that is type-dependent or value-dependent. */
23398 && (any_dependent_template_arguments_p
23402 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23403 dependent; if the argument of the `typeof' expression is not
23404 type-dependent, then it should already been have resolved. */
23410 /* A template argument pack is dependent if any of its packed
23411 arguments are. */
23413 {
23419 }
23421 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23422 be template parameters. */
23429 /* The standard does not specifically mention types that are local
23430 to template functions or local classes, but they should be
23431 considered dependent too. For example:
23433 template <int I> void f() {
23434 enum E { a = I };
23435 S<sizeof (E)> s;
23436 }
23438 The size of `E' cannot be known until the value of `I' has been
23439 determined. Therefore, `E' must be considered dependent. */
23443 /* Don't use type_dependent_expression_p here, as it can lead
23444 to infinite recursion trying to determine whether a lambda
23445 nested in a lambda is dependent (c++/47687). */
23449 && (any_dependent_template_arguments_p
23453 /* Other types are non-dependent. */
23455 }
23457 /* Returns TRUE if TYPE is dependent, in the sense of
23458 [temp.dep.type]. Note that a NULL type is considered dependent. */
23460 bool
23462 {
23463 /* If there are no template parameters in scope, then there can't be
23464 any dependent types. */
23466 {
23467 /* If we are not processing a template, then nobody should be
23468 providing us with a dependent type. */
23472 }
23474 /* If the type is NULL, we have not computed a type for the entity
23475 in question; in that case, the type is dependent. */
23479 /* Erroneous types can be considered non-dependent. */
23483 /* If we have not already computed the appropriate value for TYPE,
23484 do so now. */
23486 {
23489 }
23492 }
23494 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23495 lookup. In other words, a dependent type that is not the current
23496 instantiation. */
23498 bool
23500 {
23503 }
23505 /* T is a SCOPE_REF; return whether we need to consider it
23506 instantiation-dependent so that we can check access at instantiation
23507 time even though we know which member it resolves to. */
23509 static bool
23511 {
23517 else
23519 }
23521 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23522 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23523 expression. */
23525 /* Note that this predicate is not appropriate for general expressions;
23526 only constant expressions (that satisfy potential_constant_expression)
23527 can be tested for value dependence. */
23529 bool
23531 {
23535 /* A name declared with a dependent type. */
23540 {
23542 /* A dependent member function of the current instantiation. */
23546 /* A dependent member function of the current instantiation. */
23553 /* A name that has not been looked up -- must be dependent. */
23557 /* A non-type template parm. */
23561 /* A non-type template parm. */
23567 /* A constant with literal type and is initialized
23568 with an expression that is value-dependent.
23570 Note that a non-dependent parenthesized initializer will have
23571 already been replaced with its constant value, so if we see
23572 a TREE_LIST it must be dependent. */
23576 /* cp_finish_decl doesn't fold reference initializers. */
23582 {
23586 }
23594 /* These expressions are value-dependent if the type to which
23595 the cast occurs is dependent or the expression being casted
23596 is value-dependent. */
23597 {
23603 /* A functional cast has a list of operands. */
23606 {
23607 /* If there are no operands, it must be an expression such
23608 as "int()". This should not happen for aggregate types
23609 because it would form non-constant expressions. */
23614 }
23620 }
23625 /* FALLTHRU */
23628 /* A `sizeof' expression is value-dependent if the operand is
23629 type-dependent or is a pack expansion. */
23638 /* An 'encode' expression is value-dependent if the operand is
23639 type-dependent. */
23648 /* All instantiation-dependent expressions should also be considered
23649 value-dependent. */
23657 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
23658 is value-dependent. */
23659 {
23668 }
23671 {
23675 }
23686 {
23690 }
23693 /* Treat all requires-expressions as value-dependent so
23694 we don't try to fold them. */
23701 {
23708 {
23710 /* In a call to a constexpr member function, look through the
23711 implicit ADDR_EXPR on the object argument so that it doesn't
23712 cause the call to be considered value-dependent. We also
23713 look through it in potential_constant_expression. */
23720 }
23722 }
23725 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
23726 type-dependent. */
23731 {
23733 tree val;
23740 }
23743 /* Treat a GNU statement expression as dependent to avoid crashing
23744 under instantiate_non_dependent_expr; it can't be constant. */
23748 /* A constant expression is value-dependent if any subexpression is
23749 value-dependent. */
23751 {
23758 {
23762 {
23765 /* In some cases, some of the operands may be missing.l
23766 (For example, in the case of PREDECREMENT_EXPR, the
23767 amount to increment by may be missing.) That doesn't
23768 make the expression dependent. */
23771 }
23772 }
23776 }
23778 }
23780 /* The expression is not value-dependent. */
23782 }
23784 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
23785 [temp.dep.expr]. Note that an expression with no type is
23786 considered dependent. Other parts of the compiler arrange for an
23787 expression with type-dependent subexpressions to have no type, so
23788 this function doesn't have to be fully recursive. */
23790 bool
23792 {
23799 /* An unresolved name is always dependent. */
23805 /* A fold expression is type-dependent. */
23812 /* Some expression forms are never type-dependent. */
23826 /* The types of these expressions depends only on the type to which
23827 the cast occurs. */
23836 /* The types of these expressions depends only on the type created
23837 by the expression. */
23840 {
23841 /* For NEW_EXPR tree nodes created inside a template, either
23842 the object type itself or a TREE_LIST may appear as the
23843 operand 1. */
23846 /* This is an array type. We need to check array dimensions
23847 as well. */
23849 || value_dependent_expression_p
23851 else
23853 }
23856 {
23860 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
23861 contains an identifier associated by name lookup with one or more
23862 declarations declared with a dependent type, or...a
23863 nested-name-specifier or qualified-id that names a member of an
23864 unknown specialization. */
23867 }
23877 {
23878 tree elt;
23882 {
23885 }
23887 }
23889 /* A static data member of the current instantiation with incomplete
23890 array type is type-dependent, as the definition and specializations
23891 can have different bounds. */
23898 /* An array of unknown bound depending on a variadic parameter, eg:
23900 template<typename... Args>
23901 void foo (Args... args)
23902 {
23903 int arr[] = { args... };
23904 }
23906 template<int... vals>
23907 void bar ()
23908 {
23909 int arr[] = { vals... };
23910 }
23912 If the array has no length and has an initializer, it must be that
23913 we couldn't determine its length in cp_complete_array_type because
23914 it is dependent. */
23922 /* A function or variable template-id is type-dependent if it has any
23923 dependent template arguments. Note that we only consider the innermost
23924 template arguments here, since those are the ones that come from the
23925 template-id; the template arguments for the enclosing class do not make it
23926 type-dependent, they only make a member function value-dependent. */
23931 && (any_dependent_template_arguments_p
23935 /* Always dependent, on the number of arguments if nothing else. */
23940 {
23945 {
23951 }
23952 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
23957 {
23962 }
23965 {
23972 }
23978 {
23982 }
23984 }
23988 /* Dependent type attributes might not have made it from the decl to
23989 the type yet. */
23995 }
23997 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
23998 type-dependent if the expression refers to a member of the current
23999 instantiation and the type of the referenced member is dependent, or the
24000 class member access expression refers to a member of an unknown
24001 specialization.
24003 This function returns true if the OBJECT in such a class member access
24004 expression is of an unknown specialization. */
24006 bool
24008 {
24009 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24010 dependent. */
24015 }
24017 /* walk_tree callback function for instantiation_dependent_expression_p,
24018 below. Returns non-zero if a dependent subexpression is found. */
24020 static tree
24023 {
24025 {
24026 /* We don't have to worry about decltype currently because decltype
24027 of an instantiation-dependent expr is a dependent type. This
24028 might change depending on the resolution of DR 1172. */
24031 }
24034 {
24035 /* Don't treat an argument list as dependent just because it has no
24036 TREE_TYPE. */
24044 /* Handle expressions with type operands. */
24049 {
24054 {
24057 else
24058 {
24061 }
24062 }
24064 }
24068 /* In a template, finish_class_member_access_expr creates a
24069 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24070 type-dependent, so that we can check access control at
24071 instantiation time (PR 42277). See also Core issue 1273. */
24078 else
24081 /* Treat statement-expressions as dependent. */
24085 /* Treat requires-expressions as dependent. */
24090 /* Treat calls to function concepts as dependent. */
24096 /* And variable concepts. */
24103 }
24107 else
24109 }
24111 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24112 sense defined by the ABI:
24114 "An expression is instantiation-dependent if it is type-dependent
24115 or value-dependent, or it has a subexpression that is type-dependent
24116 or value-dependent."
24118 Except don't actually check value-dependence for unevaluated expressions,
24119 because in sizeof(i) we don't care about the value of i. Checking
24120 type-dependence will in turn check value-dependence of array bounds/template
24121 arguments as needed. */
24123 bool
24125 {
24126 tree result;
24137 }
24139 /* As above, but also check value-dependence of the expression as a whole. */
24141 bool
24143 {
24146 }
24148 /* Like type_dependent_expression_p, but it also works while not processing
24149 a template definition, i.e. during substitution or mangling. */
24151 bool
24153 {
24159 }
24161 /* Returns TRUE if ARGS contains a type-dependent expression. */
24163 bool
24165 {
24167 tree arg;
24170 {
24173 }
24175 }
24177 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24178 expressions) contains any type-dependent expressions. */
24180 bool
24182 {
24188 }
24190 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24191 expressions) contains any value-dependent expressions. */
24193 bool
24195 {
24201 }
24203 /* Returns TRUE if the ARG (a template argument) is dependent. */
24205 bool
24207 {
24211 /* Assume a template argument that was wrongly written by the user
24212 is dependent. This is consistent with what
24213 any_dependent_template_arguments_p [that calls this function]
24214 does. */
24224 {
24227 /* A member template of a dependent class is not necessarily
24228 type-dependent, but it is a dependent template argument because it
24229 will be a member of an unknown specialization to that template. */
24232 }
24234 {
24238 {
24241 }
24244 }
24247 else
24250 }
24252 /* Returns true if ARGS (a collection of template arguments) contains
24253 any types that require structural equality testing. */
24255 bool
24257 {
24267 {
24270 {
24276 {
24277 /* Look inside the argument pack. */
24280 }
24283 {
24296 }
24297 }
24298 }
24301 }
24303 /* Returns true if ARGS (a collection of template arguments) contains
24304 any dependent arguments. */
24306 bool
24308 {
24318 {
24323 }
24326 }
24328 /* Returns TRUE if the template TMPL is type-dependent. */
24330 bool
24332 {
24334 {
24336 {
24340 }
24342 }
24344 /* Template template parameters are dependent. */
24348 /* So are names that have not been looked up. */
24352 }
24354 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24356 bool
24358 {
24361 }
24363 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24364 are dependent. */
24366 bool
24368 {
24375 {
24397 {
24401 }
24405 {
24409 {
24414 }
24415 }
24416 }
24419 }
24421 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24422 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24423 no such TYPE can be found. Note that this function peers inside
24424 uninstantiated templates and therefore should be used only in
24425 extremely limited situations. ONLY_CURRENT_P restricts this
24426 peering to the currently open classes hierarchy (which is required
24427 when comparing types). */
24429 tree
24431 {
24432 tree scope;
24433 tree name;
24434 tree decl;
24436 tree pushed_scope;
24437 tree result;
24442 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24443 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24444 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24445 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24446 identifier of the TYPENAME_TYPE anymore.
24447 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24448 TYPENAME_TYPE instead, we avoid messing up with a possible
24449 typedef variant case. */
24452 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24453 it first before we can figure out what NAME refers to. */
24455 {
24457 /* Given a class template A with a dependent base with nested type C,
24458 typedef typename A::C::C C will land us here, as trying to resolve
24459 the initial A::C leads to the local C typedef, which leads back to
24460 A::C::C. So we break the recursion now. */
24462 else
24464 }
24465 /* If we don't know what SCOPE refers to, then we cannot resolve the
24466 TYPENAME_TYPE. */
24469 /* If this is a typedef, we don't want to look inside (c++/11987). */
24472 /* If SCOPE isn't the template itself, it will not have a valid
24473 TYPE_FIELDS list. */
24475 /* scope is either the template itself or a compatible instantiation
24476 like X<T>, so look up the name in the original template. */
24478 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24480 /* If scope has no fields, it can't be a current instantiation. Check this
24481 before currently_open_class to avoid infinite recursion (71515). */
24484 /* If the SCOPE is not the current instantiation, there's no reason
24485 to look inside it. */
24488 /* Enter the SCOPE so that name lookup will be resolved as if we
24489 were in the class definition. In particular, SCOPE will no
24490 longer be considered a dependent type. */
24492 /* Look up the declaration. */
24494 tf_warning_or_error);
24498 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24499 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24504 {
24508 }
24511 {
24512 tree tmpl;
24513 tree args;
24514 /* Obtain the template and the arguments. */
24517 /* Instantiate the template. */
24523 }
24525 /* Leave the SCOPE. */
24529 /* If we failed to resolve it, return the original typename. */
24533 /* If lookup found a typename type, resolve that too. */
24535 {
24536 /* Ill-formed programs can cause infinite recursion here, so we
24537 must catch that. */
24541 }
24543 /* Qualify the resulting type. */
24549 }
24551 /* EXPR is an expression which is not type-dependent. Return a proxy
24552 for EXPR that can be used to compute the types of larger
24553 expressions containing EXPR. */
24555 tree
24557 {
24558 tree inner_expr;
24560 /* When checking, try to get a constant value for all non-dependent
24561 expressions in order to expose bugs in *_dependent_expression_p
24562 and constexpr. This can affect code generation, see PR70704, so
24563 only do this for -fchecking=2. */
24566 /* Don't do this during nsdmi parsing as it can lead to
24567 unexpected recursive instantiations. */
24569 /* Don't do this during concept expansion either and for
24570 the same reason. */
24574 /* Preserve OVERLOADs; the functions must be available to resolve
24575 types. */
24586 /* There is no need to return a proxy for a variable. */
24589 /* Preserve string constants; conversions from string constants to
24590 "char *" are allowed, even though normally a "const char *"
24591 cannot be used to initialize a "char *". */
24594 /* Preserve void and arithmetic constants, as an optimization -- there is no
24595 reason to create a new node. */
24600 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
24601 There is at least one place where we want to know that a
24602 particular expression is a throw-expression: when checking a ?:
24603 expression, there are special rules if the second or third
24604 argument is a throw-expression. */
24608 /* Don't wrap an initializer list, we need to be able to look inside. */
24612 /* Don't wrap a dummy object, we need to be able to test for it. */
24631 /* If the type is unknown, it can't really be non-dependent */
24634 /* Otherwise, build a NON_DEPENDENT_EXPR. */
24636 }
24638 /* ARGS is a vector of expressions as arguments to a function call.
24639 Replace the arguments with equivalent non-dependent expressions.
24640 This modifies ARGS in place. */
24642 void
24644 {
24646 tree arg;
24649 {
24653 }
24654 }
24656 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
24657 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
24658 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
24660 static tree
24662 {
24676 }
24678 tree
24680 {
24682 }
24684 tree
24686 {
24688 }
24690 /* Return a C++17 deduction placeholder for class template TMPL. */
24692 tree
24694 {
24698 }
24700 /* Make a "constrained auto" type-specifier. This is an
24701 auto type with constraints that must be associated after
24702 deduction. The constraint is formed from the given
24703 CONC and its optional sequence of arguments, which are
24704 non-null if written as partial-concept-id. */
24706 tree
24708 {
24711 /* Build the constraint. */
24713 tree expr;
24716 else
24722 /* Our canonical type depends on the constraint. */
24725 /* Attach the constraint to the type declaration. */
24728 }
24730 /* Given type ARG, return std::initializer_list<ARG>. */
24732 static tree
24734 {
24735 tree std_init_list = namespace_binding
24737 tree argvec;
24739 {
24743 }
24748 }
24750 /* Replace auto in TYPE with std::initializer_list<auto>. */
24752 static tree
24754 {
24761 }
24763 /* Hash traits for hashing possibly constrained 'auto'
24764 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
24767 {
24770 };
24772 /* Hash the 'auto' T. */
24774 inline hashval_t
24776 {
24778 /* Matching constrained-type-specifiers denote the same template
24779 parameter, so hash the constraint. */
24781 else
24782 /* But unconstrained autos are all separate, so just hash the pointer. */
24784 }
24786 /* Compare two 'auto's. */
24790 {
24797 /* Two unconstrained autos are distinct. */
24802 }
24804 /* for_each_template_parm callback for extract_autos: if t is a (possibly
24805 constrained) auto, add it to the vector. */
24807 static int
24809 {
24812 {
24813 /* All the autos were built with index 0; fix that up now. */
24817 /* If this is a repeated constrained-type-specifier, use the index we
24818 chose before. */
24820 else
24821 {
24822 /* Otherwise this is new, so use the current count. */
24825 }
24827 }
24829 /* Always keep walking. */
24831 }
24833 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
24834 says they can appear anywhere in the type. */
24836 static tree
24838 {
24847 {
24852 }
24855 }
24857 /* The stem for deduction guide names. */
24860 /* Return the name for a deduction guide for class template TMPL. */
24862 tree
24864 {
24875 }
24877 /* True if NAME is the name of a deduction guide. */
24879 bool
24881 {
24885 }
24887 /* True if FN is a deduction guide. */
24889 bool
24891 {
24896 }
24898 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
24900 bool
24902 {
24909 }
24911 /* True if FN is a guide generated from a constructor template. */
24913 bool
24915 {
24920 {
24923 }
24925 }
24927 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
24928 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
24929 template parameter types. Note that the handling of template template
24930 parameters relies on current_template_parms being set appropriately for the
24931 new template. */
24933 static tree
24936 {
24939 tree newtype;
24942 {
24949 }
24950 else
24954 tree newdecl
24959 tree newidx;
24962 {
24972 {
24977 // First create a copy (ttargs) of tsubst_args with an
24978 // additional level for the template template parameter's own
24979 // template parameters (ttparms).
24980 tree ttparms = (INNERMOST_TEMPLATE_PARMS
24988 // Substitute ttargs into ttparms to fix references to
24989 // other template parameters.
24991 complain);
24992 // Now substitute again with args based on tparms, to reduce
24993 // the level of the ttparms.
24996 complain);
24997 // Finally, tack the adjusted parms onto tparms.
24999 current_template_parms);
25001 }
25002 }
25003 else
25004 {
25006 tree newconst
25018 }
25021 }
25023 /* Returns a C++17 class deduction guide template based on the constructor
25024 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25025 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25027 static tree
25029 {
25033 location_t loc;
25036 {
25040 {
25043 }
25044 else
25054 }
25055 else
25056 {
25060 tree fn_tmpl;
25062 {
25065 }
25066 else
25070 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25071 fully specialized args for the enclosing class. Strip those off, as
25072 the deduction guide won't have those template parameters. */
25075 /* Discard the 'this' parameter. */
25083 {
25086 /* For a member template constructor, we need to flatten the two
25087 template parameter lists into one, and then adjust the function
25088 signature accordingly. This gets...complicated. */
25092 /* For a member template we should have two levels of parms/args, one
25093 for the class and one for the constructor. We stripped
25094 specialized args for further enclosing classes above. */
25098 /* Template args for translating references to the two-level template
25099 parameters into references to the one-level template parameters we
25100 are creating. */
25105 /* Template parms for the constructor template. */
25108 /* Template parms for the class template. */
25112 /* Template parms for the deduction guide start as a copy of the
25113 template parms for the class. We set current_template_parms for
25114 lookup_template_class_1. */
25120 /* Now we need to rewrite the constructor parms to append them to the
25121 class parms. */
25123 {
25138 }
25140 /* Now we have a final set of template parms to substitute into the
25141 function signature. */
25151 }
25152 }
25155 {
25156 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25160 }
25164 FUNCTION_DECL,
25181 }
25183 /* Deduce template arguments for the class template placeholder PTYPE for
25184 template TMPL based on the initializer INIT, and return the resulting
25185 type. */
25187 static tree
25189 tsubst_flags_t complain)
25190 {
25192 {
25193 /* We should have handled this in the caller. */
25199 }
25211 else
25224 {
25227 }
25231 // FIXME cache artificial deduction guides
25233 {
25239 }
25242 {
25245 }
25247 {
25251 }
25253 /* Prune explicit deduction guides in copy-initialization context. */
25256 {
25262 {
25265 {
25269 }
25272 {
25274 " of %qT, as it has no non-explicit deduction guides or "
25277 }
25278 }
25279 }
25283 tf_decltype);
25286 {
25293 }
25299 }
25301 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25302 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25304 tree
25306 {
25308 tf_warning_or_error,
25309 adc_unspecified);
25310 }
25312 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25313 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25314 The CONTEXT determines the context in which auto deduction is performed
25315 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25316 OUTER_TARGS are used during template argument deduction
25317 (context == adc_unify) to properly substitute the result, and is ignored
25318 in other contexts.
25320 For partial-concept-ids, extra args may be appended to the list of deduced
25321 template arguments prior to determining constraint satisfaction. */
25323 tree
25327 {
25328 tree targs;
25335 /* Defining a subset of type-dependent expressions that we can deduce
25336 from ahead of time isn't worth the trouble. */
25340 /* C++17 class template argument deduction. */
25344 /* Nothing we can do with this, even in deduction context. */
25347 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25348 with either a new invented type template parameter U or, if the
25349 initializer is a braced-init-list (8.5.4), with
25350 std::initializer_list<U>. */
25352 {
25357 else
25358 {
25360 {
25364 "for deduction to %<std::initializer_list%>, use copy-"
25366 }
25368 }
25369 }
25380 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25381 and initializer has array type, deduce cv-qualified array type. */
25383 complain);
25385 {
25394 {
25398 }
25399 }
25400 else
25401 {
25403 tree tparms;
25407 else
25408 {
25412 }
25419 {
25421 /* Try again at instantiation time. */
25425 /* If type is error_mark_node a diagnostic must have been
25426 emitted by now. Also, having a mention to '<type error>'
25427 in the diagnostic is not really useful to the user. */
25428 {
25432 else
25437 }
25439 }
25440 }
25442 /* Check any placeholder constraints against the deduced type. */
25445 {
25446 /* Use the deduced type to check the associated constraints. If we
25447 have a partial-concept-id, rebuild the argument list so that
25448 we check using the extra arguments. */
25452 {
25455 }
25456 else
25459 {
25461 {
25463 {
25481 }
25483 }
25485 }
25486 }
25492 }
25494 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
25495 result. */
25497 tree
25499 {
25501 {
25507 /* In an abbreviated function template we didn't know we were dealing
25508 with a function template when we saw the auto return type, so update
25509 it to have the correct level. */
25511 }
25513 }
25515 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
25516 'decltype(auto)' or a deduced class template. */
25518 bool
25520 {
25526 else
25528 }
25530 /* for_each_template_parm callback for type_uses_auto. */
25532 int
25534 {
25536 }
25538 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
25539 a use of `auto'. Returns NULL_TREE otherwise. */
25541 tree
25543 {
25547 {
25548 /* The Concepts TS allows multiple autos in one type-specifier; just
25549 return the first one we find, do_auto_deduction will collect all of
25550 them. */
25554 else
25556 }
25557 else
25559 }
25561 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
25562 'decltype(auto)' or a concept. */
25564 bool
25566 {
25568 }
25570 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
25571 a concept identifier) iff TYPE contains a use of a generic type. Returns
25572 NULL_TREE otherwise. */
25574 tree
25576 {
25578 }
25581 /* For a given template T, return the vector of typedefs referenced
25582 in T for which access check is needed at T instantiation time.
25583 T is either a FUNCTION_DECL or a RECORD_TYPE.
25584 Those typedefs were added to T by the function
25585 append_type_to_template_for_access_check. */
25589 {
25590 tree ti;
25601 {
25606 }
25609 }
25611 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
25612 tied to T. That list of typedefs will be access checked at
25613 T instantiation time.
25614 T is either a FUNCTION_DECL or a RECORD_TYPE.
25615 TYPE_DECL is a TYPE_DECL node representing a typedef.
25616 SCOPE is the scope through which TYPE_DECL is accessed.
25617 LOCATION is the location of the usage point of TYPE_DECL.
25619 This function is a subroutine of
25620 append_type_to_template_for_access_check. */
25622 static void
25624 tree type_decl,
25625 tree scope,
25626 location_t location)
25627 {
25628 qualified_typedef_usage_t typedef_usage;
25629 tree ti;
25636 && type_decl
25650 }
25652 /* Append TYPE_DECL to the template TEMPL.
25653 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
25654 At TEMPL instanciation time, TYPE_DECL will be checked to see
25655 if it can be accessed through SCOPE.
25656 LOCATION is the location of the usage point of TYPE_DECL.
25658 e.g. consider the following code snippet:
25660 class C
25661 {
25662 typedef int myint;
25663 };
25665 template<class U> struct S
25666 {
25667 C::myint mi; // <-- usage point of the typedef C::myint
25668 };
25670 S<char> s;
25672 At S<char> instantiation time, we need to check the access of C::myint
25673 In other words, we need to check the access of the myint typedef through
25674 the C scope. For that purpose, this function will add the myint typedef
25675 and the scope C through which its being accessed to a list of typedefs
25676 tied to the template S. That list will be walked at template instantiation
25677 time and access check performed on each typedefs it contains.
25678 Note that this particular code snippet should yield an error because
25679 myint is private to C. */
25681 void
25683 tree type_decl,
25684 tree scope,
25685 location_t location)
25686 {
25692 /* Make sure we don't append the type to the template twice. */
25699 }
25701 /* Convert the generic type parameters in PARM that match the types given in the
25702 range [START_IDX, END_IDX) from the current_template_parms into generic type
25703 packs. */
25705 tree
25707 {
25718 {
25719 /* Create a distinct parameter pack type from the current parm and add it
25720 to the replacement args to tsubst below into the generic function
25721 parameter. */
25736 }
25742 /* If there are more levels then build up the replacement with the outer
25743 template parms. */
25747 replacement);
25750 }
25752 /* Entries in the decl_constraint hash table. */
25754 {
25755 tree decl;
25756 tree ci;
25757 };
25759 /* Hashing function and equality for constraint entries. */
25761 {
25763 {
25765 }
25768 {
25770 }
25771 };
25773 /* A mapping from declarations to constraint information. Note that
25774 both templates and their underlying declarations are mapped to the
25775 same constraint information.
25777 FIXME: This is defined in pt.c because garbage collection
25778 code is not being generated for constraint.cc. */
25782 /* Returns the template constraints of declaration T. If T is not
25783 constrained, return NULL_TREE. Note that T must be non-null. */
25785 tree
25787 {
25798 else
25800 }
25802 /* Associate the given constraint information CI with the declaration
25803 T. If T is a template, then the constraints are associated with
25804 its underlying declaration. Don't build associations if CI is
25805 NULL_TREE. */
25807 void
25809 {
25821 }
25823 /* Remove the associated constraints of the declaration T. */
25825 void
25827 {
25836 }
25838 /* Memoized satisfaction results for declarations. This
25839 maps the pair (constraint_info, arguments) to the result computed
25840 by constraints_satisfied_p. */
25843 {
25844 tree ci;
25845 tree args;
25846 tree result;
25847 };
25849 /* Hashing function and equality for constraint entries. */
25852 {
25854 {
25857 }
25860 {
25862 }
25863 };
25865 /* Memoized satisfaction results for concept checks. */
25868 {
25869 tree tmpl;
25870 tree args;
25871 tree result;
25872 };
25874 /* Hashing function and equality for constraint entries. */
25877 {
25879 {
25881 }
25884 {
25889 }
25890 };
25895 /* Search for a memoized satisfaction result. Returns one of the
25896 truth value nodes if previously memoized, or NULL_TREE otherwise. */
25898 tree
25900 {
25905 else
25907 }
25909 /* Memoize the result of a satisfication test. Returns the saved result. */
25911 tree
25913 {
25920 }
25922 /* Search for a memoized satisfaction result for a concept. */
25924 tree
25926 {
25931 else
25933 }
25935 /* Memoize the result of a concept check. Returns the saved result. */
25937 tree
25939 {
25946 }
25950 /* Returns a prior concept specialization. This returns the substituted
25951 and normalized constraints defined by the concept. */
25953 tree
25955 {
25960 else
25962 }
25964 /* Save a concept expansion for later. */
25966 tree
25968 {
25975 }
25977 static hashval_t
25979 {
25988 }
25990 /* Compare the constraints of two subsumption entries. The LEFT1 and
25991 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
25992 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
25994 static bool
25996 {
26004 }
26006 /* Key/value pair for learning and memoizing subsumption results. This
26007 associates a pair of check constraints (including arguments) with
26008 a boolean value indicating the result. */
26011 {
26012 tree t1;
26013 tree t2;
26015 };
26017 /* Hashing function and equality for constraint entries. */
26020 {
26022 {
26024 }
26027 {
26032 }
26033 };
26037 /* Search for a previously cached subsumption result. */
26041 {
26046 else
26048 }
26050 /* Save a subsumption result. */
26052 bool
26054 {
26061 }
26063 /* Set up the hash table for constraint association. */
26065 void
26067 {
26076 }
26078 /* Set up the hash tables for template instantiations. */
26080 void
26082 {
26085 }
26087 /* Print stats about the template hash tables for -fstats. */
26089 void
26091 {
26100 }