| blob | 2cac24f071450c769aab8716895fac71be6a41af |
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 {
1603 /* Dup decl failed, but this is a new definition. Set the
1604 line number so any errors match this new
1605 definition. */
1609 }
1610 }
1614 /* A specialization must be declared in the same namespace as the
1615 template it is specializing. */
1621 {
1630 /* If TMPL is a forward declaration of a template function, keep a list
1631 of all specializations in case we need to reassign them to a friend
1632 template later in tsubst_friend_function.
1634 Also keep a list of all variable template instantiations so that
1635 process_partial_specialization can check whether a later partial
1636 specialization would have used it. */
1639 }
1642 }
1644 /* Returns true iff two spec_entry nodes are equivalent. */
1648 bool
1650 {
1657 /* tmpl could be a FIELD_DECL for a capture pack. */
1661 {
1662 /* Partial specializations of a variable template can be distinguished by
1663 constraints. */
1667 }
1671 }
1673 /* Returns a hash for a template TMPL and template arguments ARGS. */
1675 static hashval_t
1677 {
1680 }
1682 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1683 ignoring SPEC. */
1685 hashval_t
1687 {
1689 }
1691 /* Recursively calculate a hash value for a template argument ARG, for use
1692 in the hash tables of template specializations. */
1694 hashval_t
1696 {
1716 {
1724 {
1729 }
1751 {
1755 {
1758 }
1760 }
1764 {
1767 }
1778 val = iterative_hash_template_arg
1790 val);
1792 val);
1801 /* A lambda can't appear in a template arg, but don't crash on
1802 erroneous input. */
1814 /* Now hash operands as usual. */
1819 }
1822 {
1825 {
1826 // We want an alias specialization that survived strip_typedefs
1827 // to hash differently from its TYPE_CANONICAL, to avoid hash
1828 // collisions that compare as different in template_args_equal.
1829 // These could be dependent specializations that strip_typedefs
1830 // left alone, or untouched specializations because
1831 // coerce_template_parms returns the unconverted template
1832 // arguments if it sees incomplete argument packs.
1835 }
1838 val);
1841 /* Otherwise just compare the types during lookup. */
1850 {
1855 }
1856 }
1859 }
1861 /* Unregister the specialization SPEC as a specialization of TMPL.
1862 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1863 if the SPEC was listed as a specialization of TMPL.
1865 Note that SPEC has been ggc_freed, so we can't look inside it. */
1867 bool
1869 {
1871 spec_entry elt;
1879 {
1884 }
1887 }
1889 /* Like register_specialization, but for local declarations. We are
1890 registering SPEC, an instantiation of TMPL. */
1892 void
1894 {
1896 }
1898 /* TYPE is a class type. Returns true if TYPE is an explicitly
1899 specialized class. */
1901 bool
1903 {
1907 }
1909 /* Print the list of functions at FNS, going through all the overloads
1910 for each element of the list. Alternatively, FNS can not be a
1911 TREE_LIST, in which case it will be printed together with all the
1912 overloads.
1914 MORE and *STR should respectively be FALSE and NULL when the function
1915 is called from the outside. They are used internally on recursive
1916 calls. print_candidates manages the two parameters and leaves NULL
1917 in *STR when it ends. */
1919 static void
1921 {
1927 {
1931 }
1932 else
1933 {
1936 {
1937 /* Pick the prefix string. */
1939 {
1943 }
1947 }
1950 }
1953 {
1956 }
1957 }
1959 /* Print the list of candidate FNS in an error message. FNS can also
1960 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1962 void
1964 {
1968 }
1970 /* Get a (possibly) constrained template declaration for the
1971 purpose of ordering candidates. */
1972 static tree
1974 {
1980 }
1982 /* Among candidates having the same signature, return the
1983 most constrained or NULL_TREE if there is no best candidate.
1984 If the signatures of candidates vary (e.g., template
1985 specialization vs. member function), then there can be no
1986 most constrained.
1988 Note that we don't compare constraints on the functions
1989 themselves, but rather those of their templates. */
1990 static tree
1992 {
1993 // Try to find the best candidate in a first pass.
1996 {
2003 }
2005 // Verify that the champ is better than previous candidates.
2010 }
2013 }
2016 /* Returns the template (one of the functions given by TEMPLATE_ID)
2017 which can be specialized to match the indicated DECL with the
2018 explicit template args given in TEMPLATE_ID. The DECL may be
2019 NULL_TREE if none is available. In that case, the functions in
2020 TEMPLATE_ID are non-members.
2022 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2023 specialization of a member template.
2025 The TEMPLATE_COUNT is the number of references to qualifying
2026 template classes that appeared in the name of the function. See
2027 check_explicit_specialization for a more accurate description.
2029 TSK indicates what kind of template declaration (if any) is being
2030 declared. TSK_TEMPLATE indicates that the declaration given by
2031 DECL, though a FUNCTION_DECL, has template parameters, and is
2032 therefore a template function.
2034 The template args (those explicitly specified and those deduced)
2035 are output in a newly created vector *TARGS_OUT.
2037 If it is impossible to determine the result, an error message is
2038 issued. The error_mark_node is returned to indicate failure. */
2040 static tree
2042 tree decl,
2046 tmpl_spec_kind tsk)
2047 {
2048 tree fns;
2049 tree targs;
2050 tree explicit_targs;
2053 /* A TREE_LIST of templates of which DECL may be a specialization.
2054 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2055 corresponding TREE_PURPOSE is the set of template arguments that,
2056 when used to instantiate the template, would produce a function
2057 with the signature of DECL. */
2067 /* We shouldn't be specializing a member template of an
2068 unspecialized class template; we already gave an error in
2069 check_specialization_scope, now avoid crashing. */
2072 {
2075 }
2083 /* Check for baselinks. */
2088 {
2091 }
2093 {
2096 }
2098 /* Count the number of template headers specified for this
2099 specialization. */
2109 {
2112 tf_warning_or_error,
2116 }
2118 {
2122 {
2123 tree decl_arg_types;
2124 tree fn_arg_types;
2125 tree insttype;
2127 /* In case of explicit specialization, we need to check if
2128 the number of template headers appearing in the specialization
2129 is correct. This is usually done in check_explicit_specialization,
2130 but the check done there cannot be exhaustive when specializing
2131 member functions. Consider the following code:
2133 template <> void A<int>::f(int);
2134 template <> template <> void A<int>::f(int);
2136 Assuming that A<int> is not itself an explicit specialization
2137 already, the first line specializes "f" which is a non-template
2138 member function, whilst the second line specializes "f" which
2139 is a template member function. So both lines are syntactically
2140 correct, and check_explicit_specialization does not reject
2141 them.
2143 Here, we can do better, as we are matching the specialization
2144 against the declarations. We count the number of template
2145 headers, and we check if they match TEMPLATE_COUNT + 1
2146 (TEMPLATE_COUNT is the number of qualifying template classes,
2147 plus there must be another header for the member template
2148 itself).
2150 Notice that if header_count is zero, this is not a
2151 specialization but rather a template instantiation, so there
2152 is no check we can perform here. */
2156 /* Check that the number of template arguments at the
2157 innermost level for DECL is the same as for FN. */
2165 /* DECL might be a specialization of FN. */
2169 /* For a non-static member function, we need to make sure
2170 that the const qualification is the same. Since
2171 get_bindings does not try to merge the "this" parameter,
2172 we must do the comparison explicitly. */
2178 /* Skip the "this" parameter and, for constructors of
2179 classes with virtual bases, the VTT parameter. A
2180 full specialization of a constructor will have a VTT
2181 parameter, but a template never will. */
2182 decl_arg_types
2184 fn_arg_types
2187 /* Function templates cannot be specializations; there are
2188 no partial specializations of functions. Therefore, if
2189 the type of DECL does not match FN, there is no
2190 match.
2192 Note that it should never be the case that we have both
2193 candidates added here, and for regular member functions
2194 below. */
2196 {
2200 }
2202 /* See whether this function might be a specialization of this
2203 template. Suppress access control because we might be trying
2204 to make this specialization a friend, and we have already done
2205 access control for the declaration of the specialization. */
2211 /* We cannot deduce template arguments that when used to
2212 specialize TMPL will produce DECL. */
2215 /* Remove, from the set of candidates, all those functions
2216 whose constraints are not satisfied. */
2220 // Then, try to form the new function type.
2224 fn_arg_types
2229 /* Save this template, and the arguments deduced. */
2231 }
2233 /* FN is an ordinary member function, and we need a
2234 specialization of a member template. */
2235 ;
2237 /* We can get IDENTIFIER_NODEs here in certain erroneous
2238 cases. */
2239 ;
2241 /* This is just an ordinary non-member function. Nothing can
2242 be a specialization of that. */
2243 ;
2245 /* Cannot specialize functions that are created implicitly. */
2246 ;
2247 else
2248 {
2249 tree decl_arg_types;
2251 /* This is an ordinary member function. However, since
2252 we're here, we can assume its enclosing class is a
2253 template class. For example,
2255 template <typename T> struct S { void f(); };
2256 template <> void S<int>::f() {}
2258 Here, S<int>::f is a non-template, but S<int> is a
2259 template class. If FN has the same type as DECL, we
2260 might be in business. */
2263 /* Its enclosing class is an explicit specialization
2264 of a template class. This is not a candidate. */
2269 /* The return types differ. */
2272 /* Adjust the type of DECL in case FN is a static member. */
2279 decl_arg_types))
2282 // If the deduced arguments do not satisfy the constraints,
2283 // this is not a candidate.
2287 // Add the candidate.
2289 }
2290 }
2293 {
2294 /* We have:
2296 [temp.expl.spec]
2298 It is possible for a specialization with a given function
2299 signature to be instantiated from more than one function
2300 template. In such cases, explicit specification of the
2301 template arguments must be used to uniquely identify the
2302 function template specialization being specialized.
2304 Note that here, there's no suggestion that we're supposed to
2305 determine which of the candidate templates is most
2306 specialized. However, we, also have:
2308 [temp.func.order]
2310 Partial ordering of overloaded function template
2311 declarations is used in the following contexts to select
2312 the function template to which a function template
2313 specialization refers:
2315 -- when an explicit specialization refers to a function
2316 template.
2318 So, we do use the partial ordering rules, at least for now.
2319 This extension can only serve to make invalid programs valid,
2320 so it's safe. And, there is strong anecdotal evidence that
2321 the committee intended the partial ordering rules to apply;
2322 the EDG front end has that behavior, and John Spicer claims
2323 that the committee simply forgot to delete the wording in
2324 [temp.expl.spec]. */
2327 {
2330 }
2331 }
2333 // Concepts allows multiple declarations of member functions
2334 // with the same signature. Like above, we need to rely on
2335 // on the partial ordering of those candidates to determine which
2336 // is the best.
2338 {
2340 {
2343 }
2344 }
2347 {
2354 else
2357 }
2361 {
2367 }
2369 /* We have one, and exactly one, match. */
2371 {
2375 // Propagate the candidate's constraints to the declaration.
2378 /* DECL is a re-declaration or partial instantiation of a template
2379 function. */
2382 /* It was a specialization of an ordinary member function in a
2383 template class. */
2385 }
2387 /* It was a specialization of a template. */
2390 {
2395 }
2396 else
2399 }
2401 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2402 but with the default argument values filled in from those in the
2403 TMPL_TYPES. */
2405 static tree
2407 tree tmpl_types)
2408 {
2409 tree new_spec_types;
2417 /* Substitute into the rest of the list. */
2418 new_spec_types =
2422 /* Add the default argument for this parameter. */
2425 new_spec_types);
2426 }
2428 /* DECL is an explicit specialization. Replicate default arguments
2429 from the template it specializes. (That way, code like:
2431 template <class T> void f(T = 3);
2432 template <> void f(double);
2433 void g () { f (); }
2435 works, as required.) An alternative approach would be to look up
2436 the correct default arguments at the call-site, but this approach
2437 is consistent with how implicit instantiations are handled. */
2439 static void
2441 {
2442 tree tmpl;
2443 tree spec_types;
2444 tree tmpl_types;
2445 tree new_spec_types;
2446 tree old_type;
2447 tree new_type;
2448 tree t;
2453 /* See if there's anything we need to do. */
2466 {
2467 /* Remove the this pointer, but remember the object's type for
2468 CV quals. */
2474 {
2475 /* DECL may contain more parameters than TMPL due to the extra
2476 in-charge parameter in constructors and destructors. */
2479 }
2481 {
2484 }
2485 }
2487 /* Compute the merged default arguments. */
2488 new_spec_types =
2491 /* Compute the new FUNCTION_TYPE. */
2493 {
2497 new_spec_types);
2500 /* Put the in-charge parameter back. */
2503 new_spec_types);
2507 new_spec_types);
2508 }
2509 else
2511 new_spec_types);
2521 }
2523 /* Return the number of template headers we expect to see for a definition
2524 or specialization of CTYPE or one of its non-template members. */
2526 int
2528 {
2532 {
2533 /* You're supposed to have one `template <...>' for every
2534 template class, but you don't need one for a full
2535 specialization. For example:
2537 template <class T> struct S{};
2538 template <> struct S<int> { void f(); };
2539 void S<int>::f () {}
2541 is correct; there shouldn't be a `template <>' for the
2542 definition of `S<int>::f'. */
2544 /* If CTYPE does not have template information of any
2545 kind, then it is not a template, nor is it nested
2546 within a template. */
2554 }
2557 }
2559 /* Do a simple sanity check on the template headers that precede the
2560 variable declaration DECL. */
2562 void
2564 {
2569 {
2572 "variable templates only available with "
2575 // Namespace-scope variable templates should have a template header.
2577 }
2579 {
2586 "members of an explicitly specialized class are defined "
2588 }
2589 }
2591 /* An explicit specialization whose declarator-id or class-head-name is not
2592 qualified shall be declared in the nearest enclosing namespace of the
2593 template, or, if the namespace is inline (7.3.1), any namespace from its
2594 enclosing namespace set.
2596 If the name declared in the explicit instantiation is an unqualified name,
2597 the explicit instantiation shall appear in the namespace where its template
2598 is declared or, if that namespace is inline (7.3.1), any namespace from its
2599 enclosing namespace set. */
2601 void
2603 {
2608 {
2614 /* This was allowed in C++98, so only pedwarn. */
2616 "outside its namespace must use a nested-name-"
2618 }
2619 }
2621 /* Check to see if the function just declared, as indicated in
2622 DECLARATOR, and in DECL, is a specialization of a function
2623 template. We may also discover that the declaration is an explicit
2624 instantiation at this point.
2626 Returns DECL, or an equivalent declaration that should be used
2627 instead if all goes well. Issues an error message if something is
2628 amiss. Returns error_mark_node if the error is not easily
2629 recoverable.
2631 FLAGS is a bitmask consisting of the following flags:
2633 2: The function has a definition.
2634 4: The function is a friend.
2636 The TEMPLATE_COUNT is the number of references to qualifying
2637 template classes that appeared in the name of the function. For
2638 example, in
2640 template <class T> struct S { void f(); };
2641 void S<int>::f();
2643 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2644 classes are not counted in the TEMPLATE_COUNT, so that in
2646 template <class T> struct S {};
2647 template <> struct S<int> { void f(); }
2648 template <> void S<int>::f();
2650 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2651 invalid; there should be no template <>.)
2653 If the function is a specialization, it is marked as such via
2654 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2655 is set up correctly, and it is added to the list of specializations
2656 for that template. */
2658 tree
2660 tree decl,
2663 {
2672 tmpl_spec_kind tsk;
2675 {
2678 else
2680 }
2681 else
2685 {
2688 {
2691 }
2693 {
2695 /* This could be something like:
2697 template <class T> void f(T);
2698 class S { friend void f<>(int); } */
2700 else
2701 {
2702 /* This case handles bogus declarations like template <>
2703 template <class T> void f<int>(); */
2706 declarator);
2708 }
2709 }
2713 /* The error has already been reported in
2714 check_specialization_scope. */
2720 /* Fall through. */
2733 decl);
2736 else
2740 /* Fall through. */
2746 /* In cases like template<> constexpr bool v = true;
2747 We'll give an error in check_template_variable. */
2753 else
2759 {
2760 /* This case handles bogus declarations like template <>
2761 template <class T> void f<int>(); */
2765 declarator);
2767 {
2768 /* Partial specialization of variable template. */
2772 }
2776 else
2780 ok:;
2781 }
2784 /* This is a specialization of a member template, without
2785 specialization the containing class. Something like:
2787 template <class T> struct S {
2788 template <class U> void f (U);
2789 };
2790 template <> template <class U> void S<int>::f(U) {}
2792 That's a specialization -- but of the entire template. */
2798 }
2801 /* This doesn't apply to variable templates. */
2804 {
2808 {
2812 }
2813 }
2816 {
2821 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2823 {
2824 tree fns;
2829 else
2830 {
2831 /* If there is no class context, the explicit instantiation
2832 must be at namespace scope. */
2835 /* Find the namespace binding, using the declaration
2836 context. */
2840 /* If lookup fails, look for a friend declaration so we can
2841 give a better diagnostic. */
2847 {
2850 }
2851 }
2854 }
2860 {
2862 /* A specialization in class scope. This is invalid,
2863 but the error will already have been flagged by
2864 check_specialization_scope. */
2866 else
2867 {
2868 /* It's not valid to write an explicit instantiation in
2869 class scope, e.g.:
2871 class C { template void f(); }
2873 This case is caught by the parser. However, on
2874 something like:
2876 template class C { void f(); };
2878 (which is invalid) we can get here. The error will be
2879 issued later. */
2880 ;
2881 }
2884 }
2887 {
2888 // We'll match variable templates in start_decl.
2892 /* Find the list of functions in ctype that have the same
2893 name as the declared function. */
2899 {
2904 {
2905 /* From [temp.expl.spec]:
2907 If such an explicit specialization for the member
2908 of a class template names an implicitly-declared
2909 special member function (clause _special_), the
2910 program is ill-formed.
2912 Similar language is found in [temp.explicit]. */
2915 }
2918 }
2921 {
2925 }
2926 else
2927 {
2929 tree ovl;
2931 /* For a type-conversion operator, we cannot do a
2932 name-based lookup. We might be looking for `operator
2933 int' which will be a specialization of `operator T'.
2934 So, we find *all* the conversion operators, and then
2935 select from them. */
2943 {
2945 /* There are no more conversion functions. */
2948 /* Glue all these conversion functions together
2949 with those we already have. */
2952 }
2953 }
2956 {
2959 }
2960 else
2962 }
2964 /* Figure out what exactly is being specialized at this point.
2965 Note that for an explicit instantiation, even one for a
2966 member function, we cannot tell apriori whether the
2967 instantiation is for a member template, or just a member
2968 function of a template class. Even if a member template is
2969 being instantiated, the member template arguments may be
2970 elided if they can be deduced from the rest of the
2971 declaration. */
2974 member_specialization,
2975 template_count,
2976 tsk);
2979 /* We couldn't figure out what this declaration was
2980 specializing. */
2982 else
2983 {
2986 {
2988 "friend declaration %qD is not visible to "
2992 }
3000 {
3001 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3002 is done by do_decl_instantiation later. */
3008 {
3009 /* If TMPL is not the most general template (for
3010 example, if TMPL is a friend template that is
3011 injected into namespace scope), then there will
3012 be too many levels of TARGS. Remove some of them
3013 here. */
3015 tree new_targs;
3022 }
3025 }
3027 /* If we thought that the DECL was a member function, but it
3028 turns out to be specializing a static member function,
3029 make DECL a static member function as well. */
3035 /* If this is a specialization of a member template of a
3036 template class, we want to return the TEMPLATE_DECL, not
3037 the specialization of it. */
3039 {
3044 {
3045 tree parm;
3049 /* We want to use the argument list specified in the
3050 definition, not in the original declaration. */
3055 }
3058 }
3060 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3066 /* Inherit default function arguments from the template
3067 DECL is specializing. */
3071 /* This specialization has the same protection as the
3072 template it specializes. */
3076 /* 7.1.1-1 [dcl.stc]
3078 A storage-class-specifier shall not be specified in an
3079 explicit specialization...
3081 The parser rejects these, so unless action is taken here,
3082 explicit function specializations will always appear with
3083 global linkage.
3085 The action recommended by the C++ CWG in response to C++
3086 defect report 605 is to make the storage class and linkage
3087 of the explicit specialization match the templated function:
3089 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3090 */
3092 {
3096 /* A concept cannot be specialized. */
3098 {
3100 gen_tmpl);
3102 }
3104 /* This specialization has the same linkage and visibility as
3105 the function template it specializes. */
3108 {
3111 }
3114 {
3117 }
3118 }
3120 /* If DECL is a friend declaration, declared using an
3121 unqualified name, the namespace associated with DECL may
3122 have been set incorrectly. For example, in:
3124 template <typename T> void f(T);
3125 namespace N {
3126 struct S { friend void f<int>(int); }
3127 }
3129 we will have set the DECL_CONTEXT for the friend
3130 declaration to N, rather than to the global namespace. */
3135 /* This is not really a declaration of a specialization.
3136 It's just the name of an instantiation. But, it's not
3137 a request for an instantiation, either. */
3140 /* A specialization is not necessarily COMDAT. */
3146 /* If this is a full specialization, register it so that we can find
3147 it again. Partial specializations will be registered in
3148 process_partial_specialization. */
3153 /* A 'structor should already have clones. */
3159 }
3160 }
3163 }
3165 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3166 parameters. These are represented in the same format used for
3167 DECL_TEMPLATE_PARMS. */
3169 int
3171 {
3172 const_tree p1;
3173 const_tree p2;
3181 {
3193 {
3197 /* If either of the template parameters are invalid, assume
3198 they match for the sake of error recovery. */
3211 }
3212 }
3215 /* One set of parameters has more parameters lists than the
3216 other. */
3220 }
3222 /* Determine whether PARM is a parameter pack. */
3224 bool
3226 {
3227 /* Determine if we have a non-type template parameter pack. */
3234 /* If this is a list of template parameters, we could get a
3235 TYPE_DECL or a TEMPLATE_DECL. */
3239 /* Otherwise it must be a type template parameter. */
3243 }
3245 /* Determine if T is a function parameter pack. */
3247 bool
3249 {
3253 }
3255 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3256 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3258 tree
3260 {
3267 }
3269 /* Return true iff the function parameter PARAM_DECL was expanded
3270 from the function parameter pack PACK. */
3272 bool
3274 {
3279 /* The parameter pack and its pack arguments have the same
3280 DECL_PARM_INDEX. */
3282 }
3284 /* Determine whether ARGS describes a variadic template args list,
3285 i.e., one that is terminated by a template argument pack. */
3287 static bool
3289 {
3291 tree last_parm;
3305 }
3307 /* Generate a new name for the parameter pack name NAME (an
3308 IDENTIFIER_NODE) that incorporates its */
3310 static tree
3312 {
3313 /* Munge the name to include the parameter index. */
3314 #define NUMBUF_LEN 128
3328 }
3330 /* Return true if T is a primary function, class or alias template
3331 instantiation. */
3333 bool
3335 {
3349 }
3351 /* Return true if PARM is a template template parameter. */
3353 bool
3355 {
3357 }
3359 /* Return true iff PARM is a DECL representing a type template
3360 parameter. */
3362 bool
3364 {
3369 }
3371 /* Return the template parameters of T if T is a
3372 primary template instantiation, NULL otherwise. */
3374 tree
3376 {
3381 parms = INNERMOST_TEMPLATE_PARMS
3385 }
3387 /* Return the template parameters of the LEVELth level from the full list
3388 of template parameters PARMS. */
3390 tree
3392 {
3393 tree p;
3404 }
3406 /* Returns the template arguments of T if T is a template instantiation,
3407 NULL otherwise. */
3409 tree
3411 {
3419 }
3421 /* Return the argument pack elements of T if T is a template argument pack,
3422 NULL otherwise. */
3424 tree
3426 {
3432 }
3434 /* Structure used to track the progress of find_parameter_packs_r. */
3435 struct find_parameter_pack_data
3436 {
3437 /* TREE_LIST that will contain all of the parameter packs found by
3438 the traversal. */
3441 /* Set of AST nodes that have been visited by the traversal. */
3444 /* True iff we're making a type pack expansion. */
3446 };
3448 /* Identifies all of the argument packs that occur in a template
3449 argument and appends them to the TREE_LIST inside DATA, which is a
3450 find_parameter_pack_data structure. This is a subroutine of
3451 make_pack_expansion and uses_parameter_packs. */
3452 static tree
3454 {
3460 /* Handle type aliases/typedefs. */
3462 {
3469 }
3471 /* Identify whether this is a parameter pack or not. */
3473 {
3481 /* FALLTHRU */
3483 /* If the placeholder appears in the decl-specifier-seq of a function
3484 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3485 is a pack expansion, the invented template parameter is a template
3486 parameter pack. */
3496 {
3497 /* We don't want to walk into the type of a PARM_DECL,
3498 because we don't want to see the type parameter pack. */
3501 }
3504 /* Look through a lambda capture proxy to the field pack. */
3507 {
3513 }
3515 {
3517 find_parameter_packs_r,
3520 }
3527 /* Not a parameter pack. */
3529 }
3532 {
3533 /* Add this parameter pack to the list. */
3535 }
3541 /* This switch statement will return immediately if we don't find a
3542 parameter pack. */
3544 {
3549 /* Check the template itself. */
3552 /* Check the template arguments. */
3568 /* Fall through. */
3613 {
3614 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3615 type_pack_expansion_p to false so that any placeholders
3616 within the expression don't get marked as parameter packs. */
3624 }
3628 }
3631 }
3633 /* Determines if the expression or type T uses any parameter packs. */
3634 bool
3636 {
3645 }
3647 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3648 representation a base-class initializer into a parameter pack
3649 expansion. If all goes well, the resulting node will be an
3650 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3651 respectively. */
3652 tree
3654 {
3655 tree result;
3664 {
3665 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3666 class initializer. In this case, the TREE_PURPOSE will be a
3667 _TYPE node (representing the base class expansion we're
3668 initializing) and the TREE_VALUE will be a TREE_LIST
3669 containing the initialization arguments.
3671 The resulting expansion looks somewhat different from most
3672 expansions. Rather than returning just one _EXPANSION, we
3673 return a TREE_LIST whose TREE_PURPOSE is a
3674 TYPE_PACK_EXPANSION containing the bases that will be
3675 initialized. The TREE_VALUE will be identical to the
3676 original TREE_VALUE, which is a list of arguments that will
3677 be passed to each base. We do not introduce any new pack
3678 expansion nodes into the TREE_VALUE (although it is possible
3679 that some already exist), because the TREE_PURPOSE and
3680 TREE_VALUE all need to be expanded together with the same
3681 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3682 resulting TREE_PURPOSE will mention the parameter packs in
3683 both the bases and the arguments to the bases. */
3684 tree purpose;
3685 tree value;
3688 /* Determine which parameter packs will be used by the base
3689 class expansion. */
3698 {
3702 }
3705 {
3706 /* Collect the sets of parameter packs used in each of the
3707 initialization arguments. */
3709 {
3710 /* Determine which parameter packs will be expanded in this
3711 argument. */
3714 }
3715 }
3719 /* Create the pack expansion type for the base type. */
3724 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3725 they will rarely be compared to anything. */
3729 }
3734 /* Build the PACK_EXPANSION_* node. */
3735 result = for_types
3740 {
3741 /* Propagate type and const-expression information. */
3744 /* Mark this read now, since the expansion might be length 0. */
3746 }
3747 else
3748 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3749 they will rarely be compared to anything. */
3752 /* Determine which parameter packs will be expanded. */
3759 /* Make sure we found some parameter packs. */
3761 {
3764 else
3767 }
3773 }
3775 /* Checks T for any "bare" parameter packs, which have not yet been
3776 expanded, and issues an error if any are found. This operation can
3777 only be done on full expressions or types (e.g., an expression
3778 statement, "if" condition, etc.), because we could have expressions like:
3780 foo(f(g(h(args)))...)
3782 where "args" is a parameter pack. check_for_bare_parameter_packs
3783 should not be called for the subexpressions args, h(args),
3784 g(h(args)), or f(g(h(args))), because we would produce erroneous
3785 error messages.
3787 Returns TRUE and emits an error if there were bare parameter packs,
3788 returns FALSE otherwise. */
3789 bool
3791 {
3808 {
3812 {
3821 else
3826 else
3830 }
3833 }
3836 }
3838 /* Expand any parameter packs that occur in the template arguments in
3839 ARGS. */
3840 tree
3842 {
3851 /* First, determine if we need to expand anything, and the number of
3852 slots we'll need. */
3854 {
3859 {
3863 else
3865 }
3866 else
3867 {
3869 num_result_args++;
3870 }
3871 }
3873 /* If no expansion is necessary, we're done. */
3877 /* Expand arguments. */
3880 non_default_args_count =
3883 {
3886 {
3893 }
3894 else
3895 {
3898 }
3899 }
3903 }
3905 /* Checks if DECL shadows a template parameter.
3907 [temp.local]: A template-parameter shall not be redeclared within its
3908 scope (including nested scopes).
3910 Emits an error and returns TRUE if the DECL shadows a parameter,
3911 returns FALSE otherwise. */
3913 bool
3915 {
3916 tree olddecl;
3918 /* If we're not in a template, we can't possibly shadow a template
3919 parameter. */
3923 /* Figure out what we're shadowing. */
3928 /* If there's no previous binding for this name, we're not shadowing
3929 anything, let alone a template parameter. */
3933 /* If we're not shadowing a template parameter, we're done. Note
3934 that OLDDECL might be an OVERLOAD (or perhaps even an
3935 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3936 node. */
3940 /* We check for decl != olddecl to avoid bogus errors for using a
3941 name inside a class. We check TPFI to avoid duplicate errors for
3942 inline member templates. */
3948 /* Don't complain about the injected class name, as we've already
3949 complained about the class itself. */
3956 else
3961 }
3963 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3964 ORIG_LEVEL, DECL, and TYPE. */
3966 static tree
3970 tree decl,
3971 tree type)
3972 {
3983 }
3985 /* Find the canonical type parameter for the given template type
3986 parameter. Returns the canonical type parameter, which may be TYPE
3987 if no such parameter existed. */
3989 static tree
3991 {
3992 tree list;
4006 else
4007 {
4012 }
4013 }
4015 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4016 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4017 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4018 new one is created. */
4020 static tree
4022 tsubst_flags_t complain)
4023 {
4028 {
4047 /* Template template parameters need this. */
4049 {
4056 }
4057 }
4060 }
4062 /* Process information from new template parameter PARM and append it
4063 to the LIST being built. This new parameter is a non-type
4064 parameter iff IS_NON_TYPE is true. This new parameter is a
4065 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4066 is in PARM_LOC. */
4068 tree
4071 {
4080 {
4084 {
4088 else
4090 }
4093 }
4096 {
4102 {
4103 /* [temp.param]
4105 The top-level cv-qualifiers on the template-parameter are
4106 ignored when determining its type. */
4111 && !is_parameter_pack
4112 /* If we're in a nested template parameter list, the template
4113 template parameter could be a parameter pack. */
4115 {
4116 /* This template parameter is not a parameter pack, but it
4117 should be. Complain about "bare" parameter packs. */
4120 /* Recover by calling this a parameter pack. */
4122 }
4123 }
4125 /* A template parameter is not modifiable. */
4134 processing_template_decl,
4139 }
4140 else
4141 {
4142 tree t;
4146 {
4148 /* This is for distinguishing between real templates and template
4149 template parameters */
4153 }
4154 else
4155 {
4157 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4160 }
4167 processing_template_decl,
4171 }
4175 /* Build requirements for the type/template parameter.
4176 This must be done after SET_DECL_TEMPLATE_PARM_P or
4177 process_template_parm could fail. */
4182 /* Build the parameter node linking the parameter declaration,
4183 its default argument (if any), and its constraints (if any). */
4188 }
4190 /* The end of a template parameter list has been reached. Process the
4191 tree list into a parameter vector, converting each parameter into a more
4192 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4193 as PARM_DECLs. */
4195 tree
4197 {
4202 /* Pop the dummy parameter level and add the real one. */
4205 current_template_parms
4210 {
4214 }
4219 }
4221 // Explicitly indicate the end of the template parameter list. We assume
4222 // that the current template parameters have been constructed and/or
4223 // managed explicitly, as when creating new template template parameters
4224 // from a shorthand constraint.
4225 void
4227 {
4229 }
4231 /* end_template_decl is called after a template declaration is seen. */
4233 void
4235 {
4241 /* This matches the pushlevel in begin_template_parm_list. */
4246 }
4248 /* Takes a TREE_LIST representing a template parameter and convert it
4249 into an argument suitable to be passed to the type substitution
4250 functions. Note that If the TREE_LIST contains an error_mark
4251 node, the returned argument is error_mark_node. */
4253 tree
4255 {
4268 {
4272 {
4273 /* Turn this argument into a TYPE_ARGUMENT_PACK
4274 with a single element, which expands T. */
4283 }
4284 }
4285 else
4286 {
4290 {
4291 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4292 with a single element, which expands T. */
4304 }
4305 else
4307 }
4309 }
4311 /* Given a single level of template parameters (a TREE_VEC), return it
4312 as a set of template arguments. */
4314 static tree
4316 {
4326 }
4328 /* Given a set of template parameters, return them as a set of template
4329 arguments. The template parameters are represented as a TREE_VEC, in
4330 the form documented in cp-tree.h for template arguments. */
4332 static tree
4334 {
4335 tree header;
4340 /* If there is only one level of template parameters, we do not
4341 create a TREE_VEC of TREE_VECs. Instead, we return a single
4342 TREE_VEC containing the arguments. */
4347 {
4352 else
4354 }
4357 }
4359 /* Within the declaration of a template, return the currently active
4360 template parameters as an argument TREE_VEC. */
4362 static tree
4364 {
4366 }
4368 /* Update the declared TYPE by doing any lookups which were thought to be
4369 dependent, but are not now that we know the SCOPE of the declarator. */
4371 tree
4373 {
4384 /* Don't bother building up the args in this case. */
4386 {
4387 /* tsubst in the args corresponding to the template parameters,
4388 including auto if present. Most things will be unchanged, but
4389 make_typename_type and tsubst_qualified_id will resolve
4390 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4393 tree pushed;
4395 {
4399 }
4404 }
4410 {
4413 else
4415 }
4417 }
4419 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4420 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4421 the new template is a member template. */
4423 tree
4425 {
4433 }
4435 struct template_parm_data
4436 {
4437 /* The level of the template parameters we are currently
4438 processing. */
4441 /* The index of the specialization argument we are currently
4442 processing. */
4445 /* An array whose size is the number of template parameters. The
4446 elements are nonzero if the parameter has been used in any one
4447 of the arguments processed so far. */
4450 /* An array whose size is the number of template arguments. The
4451 elements are nonzero if the argument makes use of template
4452 parameters of this level. */
4454 };
4456 /* Subroutine of push_template_decl used to see if each template
4457 parameter in a partial specialization is used in the explicit
4458 argument list. If T is of the LEVEL given in DATA (which is
4459 treated as a template_parm_data*), then DATA->PARMS is marked
4460 appropriately. */
4462 static int
4464 {
4472 {
4475 }
4477 /* In C++17 the type of a non-type argument is a deduced context. */
4482 data,
4483 NULL,
4486 /* Return zero so that for_each_template_parm will continue the
4487 traversal of the tree; we want to mark *every* template parm. */
4489 }
4491 /* Process the partial specialization DECL. */
4493 static tree
4495 {
4502 tree inner_parms;
4503 tree inst;
4513 /* A concept cannot be specialized. */
4515 {
4518 }
4523 /* We check that each of the template parameters given in the
4524 partial specialization is used in the argument list to the
4525 specialization. For example:
4527 template <class T> struct S;
4528 template <class T> struct S<T*>;
4530 The second declaration is OK because `T*' uses the template
4531 parameter T, whereas
4533 template <class T> struct S<int>;
4535 is no good. Even trickier is:
4537 template <class T>
4538 struct S1
4539 {
4540 template <class U>
4541 struct S2;
4542 template <class U>
4543 struct S2<T>;
4544 };
4546 The S2<T> declaration is actually invalid; it is a
4547 full-specialization. Of course,
4549 template <class U>
4550 struct S2<T (*)(U)>;
4552 or some such would have been OK. */
4560 {
4565 NULL,
4567 }
4570 {
4571 /* One of the template parms was not used in a deduced context in the
4572 specialization. */
4574 {
4578 }
4582 }
4587 /* [temp.class.spec]
4589 The argument list of the specialization shall not be identical to
4590 the implicit argument list of the primary template. */
4591 tree main_args
4594 && (!flag_concepts
4597 {
4601 else
4605 }
4607 /* A partial specialization that replaces multiple parameters of the
4608 primary template with a pack expansion is less specialized for those
4609 parameters. */
4611 {
4613 "primary template because it replaces multiple parameters "
4616 /* Avoid crash in process_partial_specialization. */
4618 }
4620 /* If we aren't in a dependent class, we can actually try deduction. */
4623 {
4627 maintmpl);
4628 }
4630 /* [temp.class.spec]
4632 A partially specialized non-type argument expression shall not
4633 involve template parameters of the partial specialization except
4634 when the argument expression is a simple identifier.
4636 The type of a template parameter corresponding to a specialized
4637 non-type argument shall not be dependent on a parameter of the
4638 specialization.
4640 Also, we verify that pack expansions only occur at the
4641 end of the argument list. */
4645 {
4652 {
4653 /* Extract the arguments from the argument pack. We'll be
4654 iterating over these in the following loop. */
4657 }
4660 {
4662 /* Get the Jth argument in the parameter pack. */
4666 {
4667 /* Pack expansions must come at the end of the
4668 argument list. */
4671 {
4675 else
4678 }
4679 }
4682 /* We only care about the pattern. */
4688 /* This next two lines are the `argument expression is not just a
4689 simple identifier' condition and also the `specialized
4690 non-type argument' bit. */
4694 {
4698 arg);
4699 else
4700 {
4701 /* Look at the corresponding template parameter,
4702 marking which template parameters its type depends
4703 upon. */
4707 {
4708 /* We haven't yet initialized TPD2. Do so now. */
4710 /* The number of parameters here is the number in the
4711 main template, which, as checked in the assertion
4712 above, is NARGS. */
4716 }
4718 /* Mark the template parameters. But this time, we're
4719 looking for the template parameters of the main
4720 template, not in the specialization. */
4727 NULL,
4731 {
4732 /* The type depended on some template parameters.
4733 If they are fully specialized in the
4734 specialization, that's OK. */
4743 "type %qT of template argument %qE depends "
4745 "type %qT of template argument %qE depends "
4747 type,
4748 arg);
4749 }
4750 }
4751 }
4752 }
4753 }
4755 /* We should only get here once. */
4759 // Build the template decl.
4768 /* Give template template parms a DECL_CONTEXT of the template
4769 for which they are a parameter. */
4771 {
4775 }
4778 /* We didn't register this in check_explicit_specialization so we could
4779 wait until the constraints were set. */
4781 else
4791 {
4797 {
4805 "declaration of %qD ambiguates earlier template "
4809 "partial specialization of %qD after instantiation "
4811 }
4812 }
4815 }
4817 /* PARM is a template parameter of some form; return the corresponding
4818 TEMPLATE_PARM_INDEX. */
4820 static tree
4822 {
4835 }
4837 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4838 parameter packs used by the template parameter PARM. */
4840 static void
4842 {
4843 /* A type parm can't refer to another parm. */
4847 {
4851 }
4858 }
4860 /* PARM is a template parameter pack. Return any parameter packs used in
4861 its type or the type of any of its template parameters. If there are
4862 any such packs, it will be instantiated into a fixed template parameter
4863 list by partial instantiation rather than be fully deduced. */
4865 tree
4867 {
4868 /* This can only be true in a member template. */
4871 /* This can only be true for a parameter pack. */
4874 /* A type parm can't refer to another parm. */
4888 }
4890 /* Check that a template declaration's use of default arguments and
4891 parameter packs is not invalid. Here, PARMS are the template
4892 parameters. IS_PRIMARY is true if DECL is the thing declared by
4893 a primary template. IS_PARTIAL is true if DECL is a partial
4894 specialization.
4896 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4897 declaration (but not a definition); 1 indicates a declaration, 2
4898 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4899 emitted for extraneous default arguments.
4901 Returns TRUE if there were no errors found, FALSE otherwise. */
4903 bool
4906 {
4909 tree parm_level;
4912 /* [temp.param]
4914 A default template-argument shall not be specified in a
4915 function template declaration or a function template definition, nor
4916 in the template-parameter-list of the definition of a member of a
4917 class template. */
4921 /* You can't have a function template declaration in a local
4922 scope, nor you can you define a member of a class template in a
4923 local scope. */
4931 /* A lambda doesn't have an explicit declaration; don't complain
4932 about the parms of the enclosing class. */
4939 /* If this is either a friend defined in the scope of the class
4940 or a member function. */
4946 /* And, if it was a member function, it really was defined in
4947 the scope of the class. */
4950 /* We already checked these parameters when the template was
4951 declared, so there's no need to do it again now. This function
4952 was defined in class scope, but we're processing its body now
4953 that the class is complete. */
4956 /* Core issue 226 (C++0x only): the following only applies to class
4957 templates. */
4960 {
4961 /* [temp.param]
4963 If a template-parameter has a default template-argument, all
4964 subsequent template-parameters shall have a default
4965 template-argument supplied. */
4967 {
4974 {
4984 {
4986 /* For better subsequent error-recovery, we indicate that
4987 there should have been a default argument. */
4990 }
4992 && !is_friend_decl
4993 /* Don't complain about an enclosing partial
4994 specialization. */
4999 /* A fixed parameter pack will be partially
5000 instantiated into a fixed length list. */
5002 {
5003 /* A primary class template can only have one
5004 parameter pack, at the end of the template
5005 parameter list. */
5013 }
5014 }
5015 }
5016 }
5019 || is_partial
5020 || !is_primary
5022 /* For an ordinary class template, default template arguments are
5023 allowed at the innermost level, e.g.:
5024 template <class T = int>
5025 struct S {};
5026 but, in a partial specialization, they're not allowed even
5027 there, as we have in [temp.class.spec]:
5029 The template parameter list of a specialization shall not
5030 contain default template argument values.
5032 So, for a partial specialization, or for a function template
5033 (in C++98/C++03), we look at all of them. */
5034 ;
5035 else
5036 /* But, for a primary class template that is not a partial
5037 specialization we look at all template parameters except the
5038 innermost ones. */
5041 /* Figure out what error message to issue. */
5056 else
5057 /* Per [temp.param]/9, "A default template-argument shall not be
5058 specified in the template-parameter-lists of the definition of
5059 a member of a class template that appears outside of the member's
5060 class.", thus if we aren't handling a member of a class template
5061 there is no need to examine the parameters. */
5065 /* If we're inside a class definition, there's no need to
5066 examine the parameters to the class itself. On the one
5067 hand, they will be checked when the class is defined, and,
5068 on the other, default arguments are valid in things like:
5069 template <class T = double>
5070 struct S { template <class U> void f(U); };
5071 Here the default argument for `S' has no bearing on the
5072 declaration of `f'. */
5074 else
5075 /* Check everything. */
5081 {
5088 {
5093 {
5095 {
5102 }
5104 /* Clear out the default argument so that we are not
5105 confused later. */
5107 }
5108 }
5110 /* At this point, if we're still interested in issuing messages,
5111 they must apply to classes surrounding the object declared. */
5115 }
5118 }
5120 /* Worker for push_template_decl_real, called via
5121 for_each_template_parm. DATA is really an int, indicating the
5122 level of the parameters we are interested in. If T is a template
5123 parameter of that level, return nonzero. */
5125 static int
5127 {
5133 else
5136 }
5138 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5139 DATA is really an int, indicating the innermost outer level of parameters.
5140 If T is a template parameter of that level or further out, return
5141 nonzero. */
5143 static int
5145 {
5151 else
5154 }
5156 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5157 parameters given by current_template_args, or reuses a
5158 previously existing one, if appropriate. Returns the DECL, or an
5159 equivalent one, if it is replaced via a call to duplicate_decls.
5161 If IS_FRIEND is true, DECL is a friend declaration. */
5163 tree
5165 {
5166 tree tmpl;
5167 tree args;
5168 tree info;
5169 tree ctx;
5173 /* True if the template is a member template, in the sense of
5174 [temp.mem]. */
5180 /* See if this is a partial specialization. */
5193 /* For a friend, we want the context of the friend function, not
5194 the type of which it is a friend. */
5198 /* In the case of a virtual function, we want the class in which
5199 it is defined. */
5201 else
5202 /* Otherwise, if we're currently defining some class, the DECL
5203 is assumed to be a member of the class. */
5212 /* See if this is a primary template. */
5215 /* A friend template that specifies a class context, i.e.
5216 template <typename T> friend void A<T>::f();
5217 is not primary. */
5222 else
5226 {
5233 {
5236 }
5238 {
5240 {
5243 }
5245 {
5246 /* [temp.mem]
5248 A destructor shall not be a member template. */
5251 }
5258 {
5259 /* [basic.stc.dynamic.allocation]
5261 An allocation function can be a function
5262 template. ... Template allocation functions shall
5263 have two or more parameters. */
5266 }
5267 }
5270 {
5271 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5274 {
5280 }
5281 }
5284 /* alias-declaration */
5288 else
5289 {
5292 }
5293 }
5295 /* Check to see that the rules regarding the use of default
5296 arguments are not being violated. */
5300 /* Ensure that there are no parameter packs in the type of this
5301 declaration that have not been expanded. */
5303 {
5304 /* Check each of the arguments individually to see if there are
5305 any bare parameter packs. */
5311 {
5314 {
5315 /* This is a PARM_DECL that contains unexpanded parameter
5316 packs. We have already complained about this in the
5317 check_for_bare_parameter_packs call, so just replace
5318 these types with ERROR_MARK_NODE. */
5321 }
5325 }
5327 /* Check for bare parameter packs in the return type and the
5328 exception specifiers. */
5330 /* Errors were already issued, set return type to int
5331 as the frontend doesn't expect error_mark_node as
5332 the return type. */
5336 }
5341 {
5344 }
5357 {
5362 /* If DECL is a TYPE_DECL for a class-template, then there won't
5363 be DECL_LANG_SPECIFIC. The information equivalent to
5364 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5368 {
5369 /* Since a template declaration already existed for this
5370 class-type, we must be redeclaring it here. Make sure
5371 that the redeclaration is valid. */
5373 current_template_parms,
5375 /* We don't need to create a new TEMPLATE_DECL; just use the
5376 one we already had. */
5378 }
5379 else
5380 {
5382 member_template_p);
5387 {
5388 /* A specialization of a member template of a template
5389 class. */
5393 }
5394 }
5395 }
5396 else
5397 {
5403 {
5406 }
5414 {
5415 tree new_tmpl;
5417 /* The declaration is a specialization of a member
5418 template, declared outside the class. Therefore, the
5419 innermost template arguments will be NULL, so we
5420 replace them with the arguments determined by the
5421 earlier call to check_explicit_specialization. */
5424 new_tmpl
5426 member_template_p);
5436 args,
5439 }
5441 /* Make sure the template headers we got make sense. */
5446 {
5451 }
5452 else
5454 {
5459 {
5463 else
5467 /* Avoid crash in import_export_decl. */
5470 }
5475 /* Can happen in erroneous input. */
5477 else
5479 }
5481 /* Check that the parms are used in the appropriate qualifying scopes
5482 in the declarator. */
5486 {
5492 /* Avoid crash in import_export_decl. */
5495 }
5496 }
5501 /* Push template declarations for global functions and types. Note
5502 that we do not try to push a global template friend declared in a
5503 template class; such a thing may well depend on the template
5504 parameters of the class. */
5507 {
5512 /* Hide template friend classes that haven't been declared yet. */
5514 {
5517 }
5518 }
5521 {
5527 {
5530 /* It is a conversion operator. See if the type converted to
5531 depends on innermost template operands. */
5534 depth))
5536 }
5538 /* Give template template parms a DECL_CONTEXT of the template
5539 for which they are a parameter. */
5542 {
5546 }
5552 }
5554 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5555 back to its most general template. If TMPL is a specialization,
5556 ARGS may only have the innermost set of arguments. Add the missing
5557 argument levels if necessary. */
5565 else
5566 {
5571 }
5574 && !is_friend
5577 /* Set DECL_COMDAT on template instantiations; if we force
5578 them to be emitted by explicit instantiation or -frepo,
5579 mark_needed will tell cgraph to do the right thing. */
5583 }
5585 tree
5587 {
5589 }
5591 /* FN is an inheriting constructor that inherits from the constructor
5592 template INHERITED; turn FN into a constructor template with a matching
5593 template header. */
5595 tree
5597 {
5598 tree inner_parms
5601 tree parms
5612 }
5614 /* Called when a class template TYPE is redeclared with the indicated
5615 template PARMS, e.g.:
5617 template <class T> struct S;
5618 template <class T> struct S {}; */
5620 bool
5622 {
5623 tree tmpl;
5624 tree tmpl_parms;
5628 {
5631 }
5635 /* The type is nested in some template class. Nothing to worry
5636 about here; there are no new template parameters for the nested
5637 type. */
5641 {
5643 tmpl);
5645 }
5651 {
5661 }
5664 {
5665 tree tmpl_parm;
5666 tree parm;
5667 tree tmpl_default;
5668 tree parm_default;
5682 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5683 TEMPLATE_DECL. */
5693 {
5697 }
5700 {
5701 /* We have in [temp.param]:
5703 A template-parameter may not be given default arguments
5704 by two different declarations in the same scope. */
5709 }
5712 /* Update the previous template parameters (which are the ones
5713 that will really count) with the new default value. */
5716 /* Update the new parameters, too; they'll be used as the
5717 parameters for any members. */
5720 /* Give each template template parm in this redeclaration a
5721 DECL_CONTEXT of the template for which they are a parameter. */
5723 {
5726 }
5727 }
5729 // Cannot redeclare a class template with a different set of constraints.
5731 {
5736 }
5739 }
5741 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5742 to be used when the caller has already checked
5743 (processing_template_decl
5744 && !instantiation_dependent_expression_p (expr)
5745 && potential_constant_expression (expr))
5746 and cleared processing_template_decl. */
5748 tree
5750 {
5753 complain,
5757 }
5759 /* Simplify EXPR if it is a non-dependent expression. Returns the
5760 (possibly simplified) expression. */
5762 tree
5764 {
5768 /* If we're in a template, but EXPR isn't value dependent, simplify
5769 it. We're supposed to treat:
5771 template <typename T> void f(T[1 + 1]);
5772 template <typename T> void f(T[2]);
5774 as two declarations of the same function, for example. */
5777 {
5778 processing_template_decl_sentinel s;
5780 }
5782 }
5784 tree
5786 {
5788 }
5790 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5791 an uninstantiated expression. */
5793 tree
5795 {
5799 {
5802 else
5803 {
5804 processing_template_decl_sentinel s;
5806 }
5807 }
5809 }
5811 /* True iff T is a specialization of a variable template. */
5813 bool
5815 {
5820 }
5822 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5823 template declaration, or a TYPE_DECL for an alias declaration. */
5825 bool
5827 {
5835 }
5837 /* Return TRUE iff T is a specialization of an alias template. */
5839 bool
5841 {
5842 /* It's an alias template specialization if it's an alias and its
5843 TYPE_NAME is a specialization of a primary template. */
5849 }
5851 /* An alias template is complex from a SFINAE perspective if a template-id
5852 using that alias can be ill-formed when the expansion is not, as with
5853 the void_t template. We determine this by checking whether the
5854 expansion for the alias template uses all its template parameters. */
5856 struct uses_all_template_parms_data
5857 {
5860 };
5862 static int
5864 {
5872 }
5874 static bool
5876 {
5891 }
5893 /* Return TRUE iff T is a specialization of a complex alias template with
5894 dependent template-arguments. */
5896 bool
5898 {
5911 }
5913 /* Return the number of innermost template parameters in TMPL. */
5915 static int
5917 {
5920 }
5922 /* Return either TMPL or another template that it is equivalent to under DR
5923 1286: An alias that just changes the name of a template is equivalent to
5924 the other template. */
5926 static tree
5928 {
5931 {
5932 /* Determine if the alias is equivalent to an underlying template. */
5944 tree alias_args = INNERMOST_TEMPLATE_ARGS
5949 /* Alias is equivalent. Strip it and repeat. */
5951 }
5954 }
5956 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5957 must be a reference-to-function or a pointer-to-function type, as specified
5958 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5959 and check that the resulting function has external linkage. */
5961 static tree
5963 tsubst_flags_t complain)
5964 {
5967 linkage_kind linkage;
5982 /* [temp.arg.nontype]/1
5984 A template-argument for a non-type, non-template template-parameter
5985 shall be one of:
5986 [...]
5987 -- the address of an object or function with external [C++11: or
5988 internal] linkage. */
5991 {
5993 {
5999 else
6002 }
6004 }
6008 {
6010 {
6015 else
6019 }
6021 }
6029 }
6031 /* Subroutine of convert_nontype_argument.
6032 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6033 Emit an error otherwise. */
6035 static bool
6037 tsubst_flags_t complain)
6038 {
6049 {
6053 }
6055 }
6057 /* Returns TRUE iff the address of OP is value-dependent.
6059 14.6.2.4 [temp.dep.temp]:
6060 A non-integral non-type template-argument is dependent if its type is
6061 dependent or it has either of the following forms
6062 qualified-id
6063 & qualified-id
6064 and contains a nested-name-specifier which specifies a class-name that
6065 names a dependent type.
6067 We generalize this to just say that the address of a member of a
6068 dependent class is value-dependent; the above doesn't cover the
6069 address of a static data member named with an unqualified-id. */
6071 static bool
6073 {
6074 /* We could use get_inner_reference here, but there's no need;
6075 this is only relevant for template non-type arguments, which
6076 can only be expressed as &id-expression. */
6078 {
6082 }
6085 }
6087 /* The next set of functions are used for providing helpful explanatory
6088 diagnostics for failed overload resolution. Their messages should be
6089 indented by two spaces for consistency with the messages in
6090 call.c */
6092 static int
6094 {
6096 }
6098 static int
6100 {
6105 }
6107 static int
6109 {
6111 }
6113 static int
6115 {
6121 }
6123 static int
6125 {
6129 }
6131 static int
6133 {
6136 " template parameter %qD is not a parameter pack, but "
6140 }
6142 static int
6144 {
6147 " template argument %qE does not match "
6151 }
6153 static int
6155 {
6159 }
6161 static int
6163 {
6169 }
6171 static int
6173 {
6175 {
6180 else
6182 " deduced conflicting values for non-type parameter "
6184 }
6186 }
6188 static int
6190 {
6193 " variable-sized array type %qT is not "
6195 arg);
6197 }
6199 static int
6201 {
6205 arg);
6207 }
6209 static int
6211 {
6213 {
6219 else
6224 }
6226 }
6228 static int
6230 {
6232 }
6234 static int
6237 {
6239 }
6241 static int
6244 {
6250 }
6252 static int
6255 {
6258 {
6266 }
6268 }
6270 static int
6272 {
6275 " template parameters of a template template argument are "
6278 }
6280 static int
6282 {
6288 }
6290 static int
6292 {
6297 }
6299 static int
6301 {
6305 arg);
6307 }
6309 /* Attempt to convert the non-type template parameter EXPR to the
6310 indicated TYPE. If the conversion is successful, return the
6311 converted value. If the conversion is unsuccessful, return
6312 NULL_TREE if we issued an error message, or error_mark_node if we
6313 did not. We issue error messages for out-and-out bad template
6314 parameters, but not simply because the conversion failed, since we
6315 might be just trying to do argument deduction. Both TYPE and EXPR
6316 must be non-dependent.
6318 The conversion follows the special rules described in
6319 [temp.arg.nontype], and it is much more strict than an implicit
6320 conversion.
6322 This function is called twice for each template argument (see
6323 lookup_template_class for a more accurate description of this
6324 problem). This means that we need to handle expressions which
6325 are not valid in a C++ source, but can be created from the
6326 first call (for instance, casts to perform conversions). These
6327 hacks can go away after we fix the double coercion problem. */
6329 static tree
6331 {
6332 tree expr_type;
6334 /* Detect immediately string literals as invalid non-type argument.
6335 This special-case is not needed for correctness (we would easily
6336 catch this later), but only to provide better diagnostic for this
6337 common user mistake. As suggested by DR 100, we do not mention
6338 linkage issues in the diagnostic as this is not the point. */
6339 /* FIXME we're making this OK. */
6341 {
6347 }
6349 /* Add the ADDR_EXPR now for the benefit of
6350 value_dependent_expression_p. */
6353 {
6357 }
6359 /* If we are in a template, EXPR may be non-dependent, but still
6360 have a syntactic, rather than semantic, form. For example, EXPR
6361 might be a SCOPE_REF, rather than the VAR_DECL to which the
6362 SCOPE_REF refers. Preserving the qualifying scope is necessary
6363 so that access checking can be performed when the template is
6364 instantiated -- but here we need the resolved form so that we can
6365 convert the argument. */
6378 else
6381 /* If the argument is non-dependent, perform any conversions in
6382 non-dependent context as well. */
6390 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6391 to a non-type argument of "nullptr". */
6395 /* In C++11, integral or enumeration non-type template arguments can be
6396 arbitrary constant expressions. Pointer and pointer to
6397 member arguments can be general constant expressions that evaluate
6398 to a null value, but otherwise still need to be of a specific form. */
6400 {
6402 /* A PTRMEM_CST is already constant, and a valid template
6403 argument for a parameter of pointer to member type, we just want
6404 to leave it in that form rather than lower it to a
6409 {
6413 {
6417 }
6418 }
6420 {
6425 }
6426 }
6428 /* HACK: Due to double coercion, we can get a
6429 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6430 which is the tree that we built on the first call (see
6431 below when coercing to reference to object or to reference to
6432 function). We just strip everything and get to the arg.
6433 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6434 for examples. */
6436 {
6442 {
6443 /* ??? Maybe we could use convert_from_reference here, but we
6444 would need to relax its constraints because the NOP_EXPR
6445 could actually change the type to something more cv-qualified,
6446 and this is not folded by convert_from_reference. */
6451 && (same_type_ignoring_top_level_qualifiers_p
6454 {
6457 }
6458 }
6459 }
6461 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6462 parameter is a pointer to object, through decay and
6463 qualification conversion. Let's strip everything. */
6465 {
6470 {
6471 /* Skip the ADDR_EXPR only if it is part of the decay for
6472 an array. Otherwise, it is part of the original argument
6473 in the source code. */
6478 }
6479 }
6481 /* [temp.arg.nontype]/5, bullet 1
6483 For a non-type template-parameter of integral or enumeration type,
6484 integral promotions (_conv.prom_) and integral conversions
6485 (_conv.integral_) are applied. */
6487 {
6496 /* Notice that there are constant expressions like '4 % 0' which
6497 do not fold into integer constants. */
6500 {
6502 {
6513 /* else cxx_constant_value complained but gave us
6514 a real constant, so go ahead. */
6516 }
6517 else
6519 }
6521 /* Avoid typedef problems. */
6524 }
6525 /* [temp.arg.nontype]/5, bullet 2
6527 For a non-type template-parameter of type pointer to object,
6528 qualification conversions (_conv.qual_) and the array-to-pointer
6529 conversion (_conv.array_) are applied. */
6531 {
6532 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6534 A template-argument for a non-type, non-template template-parameter
6535 shall be one of: [...]
6537 -- the name of a non-type template-parameter;
6538 -- the address of an object or function with external linkage, [...]
6539 expressed as "& id-expression" where the & is optional if the name
6540 refers to a function or array, or if the corresponding
6541 template-parameter is a reference.
6543 Here, we do not care about functions, as they are invalid anyway
6544 for a parameter of type pointer-to-object. */
6547 /* Non-type template parameters are OK. */
6548 ;
6553 {
6555 {
6558 "because %qD is a variable, not the address of "
6561 }
6563 {
6569 }
6570 /* Other values, like integer constants, might be valid
6571 non-type arguments of some other type. */
6573 }
6574 else
6575 {
6576 tree decl;
6581 {
6586 }
6588 {
6594 }
6596 {
6601 }
6602 }
6611 }
6612 /* [temp.arg.nontype]/5, bullet 3
6614 For a non-type template-parameter of type reference to object, no
6615 conversions apply. The type referred to by the reference may be more
6616 cv-qualified than the (otherwise identical) type of the
6617 template-argument. The template-parameter is bound directly to the
6618 template-argument, which must be an lvalue. */
6620 {
6622 expr_type))
6626 {
6631 }
6634 {
6639 }
6641 /* [temp.arg.nontype]/1
6643 A template-argument for a non-type, non-template template-parameter
6644 shall be one of: [...]
6646 -- the address of an object or function with external linkage. */
6649 {
6652 {
6655 "because a reference variable does not have a constant "
6658 }
6659 }
6662 {
6664 {
6670 }
6672 /* DR 1155 allows internal linkage in C++11 and up. */
6675 {
6681 }
6684 }
6685 }
6686 /* [temp.arg.nontype]/5, bullet 4
6688 For a non-type template-parameter of type pointer to function, only
6689 the function-to-pointer conversion (_conv.func_) is applied. If the
6690 template-argument represents a set of overloaded functions (or a
6691 pointer to such), the matching function is selected from the set
6692 (_over.over_). */
6694 {
6695 /* If the argument is a template-id, we might not have enough
6696 context information to decay the pointer. */
6698 {
6702 }
6705 /* Null pointer values are OK in C++11. */
6711 }
6712 /* [temp.arg.nontype]/5, bullet 5
6714 For a non-type template-parameter of type reference to function, no
6715 conversions apply. If the template-argument represents a set of
6716 overloaded functions, the matching function is selected from the set
6717 (_over.over_). */
6719 {
6721 {
6723 {
6728 }
6730 }
6735 }
6736 /* [temp.arg.nontype]/5, bullet 6
6738 For a non-type template-parameter of type pointer to member function,
6739 no conversions apply. If the template-argument represents a set of
6740 overloaded member functions, the matching member function is selected
6741 from the set (_over.over_). */
6743 {
6748 /* [temp.arg.nontype] bullet 1 says the pointer to member
6749 expression must be a pointer-to-member constant. */
6754 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6755 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6759 /* There is no way to disable standard conversions in
6760 resolve_address_of_overloaded_function (called by
6761 instantiate_type). It is possible that the call succeeded by
6762 converting &B::I to &D::I (where B is a base of D), so we need
6763 to reject this conversion here.
6765 Actually, even if there was a way to disable standard conversions,
6766 it would still be better to reject them here so that we can
6767 provide a superior diagnostic. */
6769 {
6771 {
6775 /* If we are just one standard conversion off, explain. */
6779 }
6781 }
6782 }
6783 /* [temp.arg.nontype]/5, bullet 7
6785 For a non-type template-parameter of type pointer to data member,
6786 qualification conversions (_conv.qual_) are applied. */
6788 {
6789 /* [temp.arg.nontype] bullet 1 says the pointer to member
6790 expression must be a pointer-to-member constant. */
6798 }
6800 {
6802 {
6807 }
6809 }
6810 /* A template non-type parameter must be one of the above. */
6811 else
6814 /* Sanity check: did we actually convert the argument to the
6815 right type? */
6819 }
6821 /* Subroutine of coerce_template_template_parms, which returns 1 if
6822 PARM_PARM and ARG_PARM match using the rule for the template
6823 parameters of template template parameters. Both PARM and ARG are
6824 template parameters; the rest of the arguments are the same as for
6825 coerce_template_template_parms.
6826 */
6827 static int
6829 tree arg,
6830 tsubst_flags_t complain,
6831 tree in_decl,
6832 tree outer_args)
6833 {
6842 {
6844 /* We encounter instantiations of templates like
6845 template <template <template <class> class> class TT>
6846 class C; */
6847 {
6854 }
6855 /* Fall through. */
6860 /* Argument is a parameter pack but parameter is not. */
6865 /* The tsubst call is used to handle cases such as
6867 template <int> class C {};
6868 template <class T, template <T> class TT> class D {};
6869 D<int, C> d;
6871 i.e. the parameter list of TT depends on earlier parameters. */
6873 {
6878 }
6882 /* Argument is a parameter pack but parameter is not. */
6889 }
6892 }
6894 /* Coerce template argument list ARGLIST for use with template
6895 template-parameter TEMPL. */
6897 static tree
6899 tsubst_flags_t complain)
6900 {
6901 /* Consider an example where a template template parameter declared as
6903 template <class T, class U = std::allocator<T> > class TT
6905 The template parameter level of T and U are one level larger than
6906 of TT. To proper process the default argument of U, say when an
6907 instantiation `TT<int>' is seen, we need to build the full
6908 arguments containing {int} as the innermost level. Outer levels,
6909 available when not appearing as default template argument, can be
6910 obtained from the arguments of the enclosing template.
6912 Suppose that TT is later substituted with std::vector. The above
6913 instantiation is `TT<int, std::allocator<T> >' with TT at
6914 level 1, and T at level 2, while the template arguments at level 1
6915 becomes {std::vector} and the inner level 2 is {int}. */
6919 {
6921 /* We want arguments for the partial specialization, not arguments for
6922 the primary template. */
6924 else
6926 }
6928 {
6929 /* This is an argument of the current template, so we haven't set
6930 DECL_CONTEXT yet. */
6931 tree relevant_template_parms;
6933 /* Parameter levels that are greater than the level of the given
6934 template template parm are irrelevant. */
6941 }
6948 complain,
6951 }
6953 /* A cache of template template parameters with match-all default
6954 arguments. */
6956 static void
6958 {
6962 }
6963 static tree
6965 {
6970 }
6972 /* T is a bound template template-parameter. Copy its arguments into default
6973 arguments of the template template-parameter's template parameters. */
6975 static tree
6977 {
7000 {
7003 {
7006 }
7007 }
7011 }
7013 /* ARG is a bound potential template template-argument, and PARGS is a list
7014 of arguments for the corresponding template template-parameter. Adjust
7015 PARGS as appropriate for application to ARG's template, and if ARG is a
7016 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7017 arguments to the template template parameter. */
7019 static tree
7021 {
7025 {
7026 /* When comparing two template template-parameters in partial ordering,
7027 rewrite the one currently being used as an argument to have default
7028 arguments for all parameters. */
7034 }
7035 else
7036 {
7037 tree aparms
7042 }
7045 }
7047 /* Subroutine of unify for the case when PARM is a
7048 BOUND_TEMPLATE_TEMPLATE_PARM. */
7050 static int
7053 {
7057 /* The template template parm might be variadic and the argument
7058 not, so flatten both argument lists. */
7064 {
7065 /* In keeping with P0522R0, adjust P's template arguments
7066 to apply to A's template; then flatten it again. */
7069 }
7075 /* If the P0522 adjustment eliminated a pack expansion, deduce
7076 empty packs. */
7084 }
7086 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7087 template template parameters. Both PARM_PARMS and ARG_PARMS are
7088 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7089 or PARM_DECL.
7091 Consider the example:
7092 template <class T> class A;
7093 template<template <class U> class TT> class B;
7095 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7096 the parameters to A, and OUTER_ARGS contains A. */
7098 static int
7100 tree arg_parms,
7101 tsubst_flags_t complain,
7102 tree in_decl,
7103 tree outer_args)
7104 {
7116 {
7117 /* P0522R0: A template template-parameter P is at least as specialized as
7118 a template template-argument A if, given the following rewrite to two
7119 function templates, the function template corresponding to P is at
7120 least as specialized as the function template corresponding to A
7121 according to the partial ordering rules for function templates
7122 ([temp.func.order]). Given an invented class template X with the
7123 template parameter list of A (including default arguments):
7125 * Each of the two function templates has the same template parameters,
7126 respectively, as P or A.
7128 * Each function template has a single function parameter whose type is
7129 a specialization of X with template arguments corresponding to the
7130 template parameters from the respective function template where, for
7131 each template parameter PP in the template parameter list of the
7132 function template, a corresponding template argument AA is formed. If
7133 PP declares a parameter pack, then AA is the pack expansion
7134 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7136 If the rewrite produces an invalid type, then P is not at least as
7137 specialized as A. */
7139 /* So coerce P's args to apply to A's parms, and then deduce between A's
7140 args and the converted args. If that succeeds, A is at least as
7141 specialized as P, so they match.*/
7148 {
7154 }
7155 }
7157 /* Determine whether we have a parameter pack at the end of the
7158 template template parameter's template parameter list. */
7160 {
7167 {
7181 }
7182 }
7188 /* Check all of the template parameters except the parameter pack at
7189 the end (if any). */
7191 {
7200 outer_args))
7203 }
7206 {
7207 /* Check each of the template parameters in the template
7208 argument against the template parameter pack at the end of
7209 the template template parameter. */
7216 {
7223 outer_args))
7225 }
7226 }
7229 }
7231 /* Verifies that the deduced template arguments (in TARGS) for the
7232 template template parameters (in TPARMS) represent valid bindings,
7233 by comparing the template parameter list of each template argument
7234 to the template parameter list of its corresponding template
7235 template parameter, in accordance with DR150. This
7236 routine can only be called after all template arguments have been
7237 deduced. It will return TRUE if all of the template template
7238 parameter bindings are okay, FALSE otherwise. */
7239 bool
7241 {
7245 /* We're dealing with template parms in this process. */
7251 {
7256 {
7261 {
7262 /* Look inside the argument pack. */
7265 }
7268 {
7272 /* Extract the next argument from the argument
7273 pack. */
7277 /* Look at the pattern of the pack expansion. */
7280 /* Extract the template parameters from the template
7281 argument. */
7287 /* Verify that we can coerce the template template
7288 parameters from the template argument to the template
7289 parameter. This requires an exact match. */
7291 && !coerce_template_template_parms
7293 targ_parms,
7294 tf_none,
7295 tparm,
7296 targs))
7297 {
7300 }
7301 }
7302 }
7303 }
7305 out:
7309 }
7311 /* Since type attributes aren't mangled, we need to strip them from
7312 template type arguments. */
7314 static tree
7316 {
7326 }
7328 /* And from inside dependent non-type arguments like sizeof(Type). */
7330 static tree
7332 {
7342 }
7344 // A template declaration can be substituted for a constrained
7345 // template template parameter only when the argument is more
7346 // constrained than the parameter.
7347 static bool
7349 {
7352 /* For now, allow constrained template template arguments
7353 and unconstrained template template parameters. */
7359 // If the template parameter is constrained, we need to rewrite its
7360 // constraints in terms of the ARG's template parameters. This ensures
7361 // that all of the template parameter types will have the same depth.
7362 //
7363 // Note that this is only valid when coerce_template_template_parm is
7364 // true for the innermost template parameters of PARM and ARG. In other
7365 // words, because coercion is successful, this conversion will be valid.
7367 {
7374 }
7377 }
7379 // Convert a placeholder argument into a binding to the original
7380 // parameter. The original parameter is saved as the TREE_TYPE of
7381 // ARG.
7384 {
7387 }
7389 /* Convert the indicated template ARG as necessary to match the
7390 indicated template PARM. Returns the converted ARG, or
7391 error_mark_node if the conversion was unsuccessful. Error and
7392 warning messages are issued under control of COMPLAIN. This
7393 conversion is for the Ith parameter in the parameter list. ARGS is
7394 the full set of template arguments deduced so far. */
7396 static tree
7398 tree arg,
7399 tree args,
7400 tsubst_flags_t complain,
7402 tree in_decl)
7403 {
7404 tree orig_arg;
7405 tree val;
7411 /* Trivially convert placeholders. */
7420 {
7421 /* The template argument was the name of some
7422 member function. That's usually
7423 invalid, but static members are OK. In any
7424 case, grab the underlying fields/functions
7425 and issue an error later if required. */
7428 }
7436 /* When determining whether an argument pack expansion is a template,
7437 look at the pattern. */
7441 /* Deal with an injected-class-name used as a template template arg. */
7443 {
7446 {
7456 }
7457 }
7459 is_tmpl_type =
7475 {
7477 {
7481 }
7484 "to refer to a type member of a template parameter, "
7489 typename_type,
7490 complain);
7493 }
7495 {
7497 {
7499 {
7511 else
7514 }
7515 }
7517 }
7519 {
7521 {
7528 else
7531 }
7533 }
7536 {
7538 {
7542 /* The number of argument required is not known yet.
7543 Just accept it for now. */
7545 else
7546 {
7548 tree argparm;
7550 /* Strip alias templates that are equivalent to another
7551 template. */
7557 args))
7558 {
7561 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7562 TEMPLATE_DECL. */
7564 {
7569 }
7570 }
7571 else
7572 {
7574 {
7581 }
7584 }
7586 // Check that the constraints are compatible before allowing the
7587 // substitution.
7590 {
7592 {
7598 }
7600 }
7601 }
7602 }
7603 else
7605 /* We only form one instance of each template specialization.
7606 Therefore, if we use a non-canonical variant (i.e., a
7607 typedef), any future messages referring to the type will use
7608 the typedef, which is confusing if those future uses do not
7609 themselves also use the typedef. */
7612 }
7613 else
7614 {
7618 {
7620 /* There's nothing to check for an auto argument pack. */
7626 }
7627 else
7634 {
7637 else
7638 {
7639 /* Not sure if this is reachable, but it doesn't hurt
7640 to be robust. */
7643 }
7644 }
7647 /* We used to call digest_init here. However, digest_init
7648 will report errors, which we don't want when complain
7649 is zero. More importantly, digest_init will try too
7650 hard to convert things: for example, `0' should not be
7651 converted to pointer type at this point according to
7652 the standard. Accepting this is not merely an
7653 extension, since deciding whether or not these
7654 conversions can occur is part of determining which
7655 function template to call, or whether a given explicit
7656 argument specification is valid. */
7658 else
7668 {
7669 /* Reject template arguments that are references to built-in
7670 functions with no library fallbacks. */
7679 }
7682 {
7683 /* Strip typedefs from the SCOPE_REF. */
7686 complain);
7689 }
7690 }
7693 }
7695 /* Coerces the remaining template arguments in INNER_ARGS (from
7696 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7697 Returns the coerced argument pack. PARM_IDX is the position of this
7698 parameter in the template parameter list. ARGS is the original
7699 template argument list. */
7700 static tree
7703 tree args,
7704 tree inner_args,
7706 tree new_args,
7708 tree in_decl,
7709 tsubst_flags_t complain)
7710 {
7713 tree packed_args;
7714 tree argument_pack;
7721 {
7722 /* When the template parameter is a non-type template parameter pack
7723 or template template parameter pack whose type or template
7724 parameters use parameter packs, we know exactly how many arguments
7725 we are looking for. Build a vector of the instantiated decls for
7726 these template parameters in PACKED_PARMS. */
7727 /* We can't use make_pack_expansion here because it would interpret a
7728 _DECL as a use rather than a declaration. */
7742 /* If we're doing a partial instantiation of a member template,
7743 verify that all of the types used for the non-type
7744 template parameter pack are, in fact, valid for non-type
7745 template parameters. */
7748 {
7751 {
7755 }
7756 /* We don't know how many args we have yet, just
7757 use the unconverted ones for now. */
7759 }
7762 }
7763 /* Check if we have a placeholder pack, which indicates we're
7764 in the context of a introduction list. In that case we want
7765 to match this pack to the single placeholder. */
7769 {
7772 }
7773 else
7776 /* Convert the remaining arguments, which will be a part of the
7777 parameter pack "parm". */
7780 {
7786 {
7787 /* Once we've packed as many args as we have types, stop. */
7791 /* We don't know how many args we have yet, just
7792 use the unconverted ones for now. */
7794 else
7796 }
7799 {
7802 }
7803 else
7806 in_decl);
7810 }
7814 {
7819 }
7824 else
7825 {
7830 }
7837 }
7839 /* Returns the number of pack expansions in the template argument vector
7840 ARGS. */
7842 static int
7844 {
7849 {
7853 }
7855 }
7857 /* Convert all template arguments to their appropriate types, and
7858 return a vector containing the innermost resulting template
7859 arguments. If any error occurs, return error_mark_node. Error and
7860 warning messages are issued under control of COMPLAIN.
7862 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7863 for arguments not specified in ARGS. Otherwise, if
7864 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7865 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7866 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7867 ARGS. */
7869 static tree
7871 tree args,
7872 tree in_decl,
7873 tsubst_flags_t complain,
7876 {
7878 tree orig_inner_args;
7879 tree inner_args;
7880 tree new_args;
7881 tree new_inner_args;
7885 /* When used as a boolean value, indicates whether this is a
7886 variadic template parameter list. Since it's an int, we can also
7887 subtract it from nparms to get the number of non-variadic
7888 parameters. */
7893 /* Likewise for parameters with default arguments. */
7901 /* Determine if there are any parameter packs or default arguments. */
7903 {
7911 }
7914 /* If there are no parameters that follow a parameter pack, we need to
7915 expand any argument packs so that we can deduce a parameter pack from
7916 some non-packed args followed by an argument pack, as in variadic85.C.
7917 If there are such parameters, we need to leave argument packs intact
7918 so the arguments are assigned properly. This can happen when dealing
7919 with a nested class inside a partial specialization of a class
7920 template, as in variadic92.C, or when deducing a template parameter pack
7921 from a sub-declarator, as in variadic114.C. */
7925 /* Count any pack expansion args. */
7931 && require_all_args
7932 && !variadic_args_p
7933 && (!use_default_args
7936 {
7938 {
7940 {
7944 }
7945 else
7952 }
7955 }
7956 /* We can't pass a pack expansion to a non-pack parameter of an alias
7957 template (DR 1430). */
7961 && variadic_args_p
7963 {
7965 {
7967 {
7973 {
7976 "pack expansion argument for non-pack parameter "
7978 else
7980 "pack expansion argument for non-pack parameter "
7984 }
7985 }
7987 found:;
7988 }
7990 }
7992 /* We need to evaluate the template arguments, even though this
7993 template-id may be nested within a "sizeof". */
8002 {
8003 tree arg;
8004 tree parm;
8006 /* Get the Ith template parameter. */
8010 {
8013 }
8015 /* Calculate the next argument. */
8018 else
8023 {
8024 /* Some arguments will be placed in the
8025 template parameter pack PARM. */
8032 {
8033 /* We don't know how many args we have yet, just use the
8034 unconverted (and still packed) ones for now. */
8038 }
8042 /* Store this argument. */
8044 {
8045 lost++;
8046 /* We are done with all of the arguments. */
8048 }
8049 else
8050 {
8053 }
8056 }
8058 {
8060 {
8061 /* "If every valid specialization of a variadic template
8062 requires an empty template parameter pack, the template is
8063 ill-formed, no diagnostic required." So check that the
8064 pattern works with this parameter. */
8069 in_decl);
8071 {
8076 }
8078 /* Recover from missing typename. */
8082 /* We don't know how many args we have yet, just
8083 use the unconverted ones for now. */
8087 }
8088 }
8090 {
8091 /* There must be a default arg in this case. */
8094 /* The position of the first default template argument,
8095 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8096 Record that. */
8100 }
8101 else
8105 {
8108 }
8110 /* This only occurs if there was an error in the template
8111 parameter list itself (which we would already have
8112 reported) that we are trying to recover from, e.g., a class
8113 template with a parameter list such as
8114 template<typename..., typename>. */
8116 else
8122 lost++;
8124 }
8129 {
8131 {
8136 }
8138 }
8148 }
8150 /* Convert all template arguments to their appropriate types, and
8151 return a vector containing the innermost resulting template
8152 arguments. If any error occurs, return error_mark_node. Error and
8153 warning messages are not issued.
8155 Note that no function argument deduction is performed, and default
8156 arguments are used to fill in unspecified arguments. */
8157 tree
8159 {
8161 }
8163 /* Convert all template arguments to their appropriate type, and
8164 instantiate default arguments as needed. This returns a vector
8165 containing the innermost resulting template arguments, or
8166 error_mark_node if unsuccessful. */
8167 tree
8169 tsubst_flags_t complain)
8170 {
8172 }
8174 /* Like coerce_template_parms. If PARMS represents all template
8175 parameters levels, this function returns a vector of vectors
8176 representing all the resulting argument levels. Note that in this
8177 case, only the innermost arguments are coerced because the
8178 outermost ones are supposed to have been coerced already.
8180 Otherwise, if PARMS represents only (the innermost) vector of
8181 parameters, this function returns a vector containing just the
8182 innermost resulting arguments. */
8184 static tree
8186 tree args,
8187 tree in_decl,
8188 tsubst_flags_t complain,
8191 {
8194 tree coerced_args;
8197 {
8199 tree level;
8205 {
8206 tree l;
8210 require_all_args,
8211 use_default_args);
8212 else
8219 }
8220 }
8221 else
8224 require_all_args,
8225 use_default_args);
8227 }
8229 /* Returns 1 if template args OT and NT are equivalent. */
8231 int
8233 {
8242 /* For member templates */
8251 {
8268 }
8272 {
8275 /* Don't treat an alias template specialization with dependent
8276 arguments as equivalent to its underlying type when used as a
8277 template argument; we need them to be distinct so that we
8278 substitute into the specialization arguments at instantiation
8279 time. And aliases can't be equivalent without being ==, so
8280 we don't need to look any deeper. */
8283 else
8285 }
8288 else
8289 {
8290 /* Try to treat a template non-type argument that has been converted
8291 to the parameter type as equivalent to one that hasn't yet. */
8304 }
8305 }
8307 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8308 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8309 NEWARG_PTR with the offending arguments if they are non-NULL. */
8311 int
8314 {
8327 {
8332 {
8338 }
8339 }
8341 }
8343 static void
8345 {
8355 /* We are called both from instantiate_decl, where we've already had a
8356 tinst_level pushed, and instantiate_template, where we haven't.
8357 Compensate. */
8368 else
8377 }
8380 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8381 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8382 documentation for TEMPLATE_ID_EXPR. */
8384 tree
8386 {
8387 tree type;
8395 {
8398 }
8401 {
8403 unknown_type_node,
8405 arglist);
8407 }
8414 }
8416 /* Within the scope of a template class S<T>, the name S gets bound
8417 (in build_self_reference) to a TYPE_DECL for the class, not a
8418 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8419 or one of its enclosing classes, and that type is a template,
8420 return the associated TEMPLATE_DECL. Otherwise, the original
8421 DECL is returned.
8423 Also handle the case when DECL is a TREE_LIST of ambiguous
8424 injected-class-names from different bases. */
8426 tree
8428 {
8432 /* DR 176: A lookup that finds an injected-class-name (10.2
8433 [class.member.lookup]) can result in an ambiguity in certain cases
8434 (for example, if it is found in more than one base class). If all of
8435 the injected-class-names that are found refer to specializations of
8436 the same class template, and if the name is followed by a
8437 template-argument-list, the reference refers to the class template
8438 itself and not a specialization thereof, and is not ambiguous. */
8440 {
8443 {
8449 }
8452 else
8454 }
8460 }
8462 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8463 parameters, find the desired type.
8465 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8467 IN_DECL, if non-NULL, is the template declaration we are trying to
8468 instantiate.
8470 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8471 the class we are looking up.
8473 Issue error and warning messages under control of COMPLAIN.
8475 If the template class is really a local class in a template
8476 function, then the FUNCTION_CONTEXT is the function in which it is
8477 being instantiated.
8479 ??? Note that this function is currently called *twice* for each
8480 template-id: the first time from the parser, while creating the
8481 incomplete type (finish_template_type), and the second type during the
8482 real instantiation (instantiate_template_class). This is surely something
8483 that we want to avoid. It also causes some problems with argument
8484 coercion (see convert_nontype_argument for more information on this). */
8486 static tree
8489 {
8491 tree t;
8494 spec_entry elt;
8495 hashval_t hash;
8498 {
8502 else
8503 {
8510 }
8513 }
8515 {
8518 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8519 an implicit typename for the second A. Deal with it. */
8524 {
8527 }
8528 }
8531 {
8534 }
8536 {
8540 }
8542 {
8545 }
8547 /* Issue an error message if we didn't find a template. */
8549 {
8553 }
8556 /* Make sure it's a user visible template, if it was named by
8557 the user. */
8560 {
8562 {
8566 }
8568 }
8572 /* An alias that just changes the name of a template is equivalent to the
8573 other template, so if any of the arguments are pack expansions, strip
8574 the alias to avoid problems with a pack expansion passed to a non-pack
8575 alias template parameter (DR 1430). */
8580 {
8581 tree parm;
8590 }
8591 else
8592 {
8594 tree gen_tmpl;
8595 tree type_decl;
8603 /* An error occurred while building the template TEMPL, and a
8604 diagnostic has most certainly been emitted for that
8605 already. Let's propagate that error. */
8614 {
8615 /* We've been given an incomplete set of template arguments.
8616 For example, given:
8618 template <class T> struct S1 {
8619 template <class U> struct S2 {};
8620 template <class U> struct S2<U*> {};
8621 };
8623 we will be called with an ARGLIST of `U*', but the
8624 TEMPLATE will be `template <class T> template
8625 <class U> struct S1<T>::S2'. We must fill in the missing
8626 arguments. */
8630 }
8632 /* Now we should have enough arguments. */
8635 /* From here on, we're only interested in the most general
8636 template. */
8638 /* Calculate the BOUND_ARGS. These will be the args that are
8639 actually tsubst'd into the definition to create the
8640 instantiation. */
8642 complain,
8647 /* We were unable to bind the arguments. */
8650 /* In the scope of a template class, explicit references to the
8651 template class refer to the type of the template, not any
8652 instantiation of it. For example, in:
8654 template <class T> class C { void f(C<T>); }
8656 the `C<T>' is just the same as `C'. Outside of the
8657 class, however, such a reference is an instantiation. */
8661 {
8666 }
8668 /* If we already have this specialization, return it. */
8678 /* If the the template's constraints are not satisfied,
8679 then we cannot form a valid type.
8681 Note that the check is deferred until after the hash
8682 lookup. This prevents redundant checks on previously
8683 instantiated specializations. */
8685 {
8687 {
8690 }
8692 }
8696 /* If the deduced arguments are invalid, then the binding
8697 failed. */
8701 complain))
8708 {
8713 }
8723 /* Create the type. */
8725 {
8726 /* The user referred to a specialization of an alias
8727 template represented by GEN_TMPL.
8729 [temp.alias]/2 says:
8731 When a template-id refers to the specialization of an
8732 alias template, it is equivalent to the associated
8733 type obtained by substitution of its
8734 template-arguments for the template-parameters in the
8735 type-id of the alias template. */
8738 /* Note that the call above (by indirectly calling
8739 register_specialization in tsubst_decl) registers the
8740 TYPE_DECL representing the specialization of the alias
8741 template. So next time someone substitutes ARGLIST for
8742 the template parms into the alias template (GEN_TMPL),
8743 she'll get that TYPE_DECL back. */
8747 }
8749 {
8751 {
8762 }
8763 else
8764 {
8765 /* We don't want to call start_enum for this type, since
8766 the values for the enumeration constants may involve
8767 template parameters. And, no one should be interested
8768 in the enumeration constants for such a type. */
8771 }
8775 }
8777 {
8783 /* A local class. Make sure the decl gets registered properly. */
8788 /* This instantiation is another name for the primary
8789 template type. Set the TYPE_CANONICAL field
8790 appropriately. */
8793 /* Some of the template arguments require structural
8794 equality testing, so this template class requires
8795 structural equality testing. */
8797 }
8798 else
8801 /* If we called start_enum or pushtag above, this information
8802 will already be set up. */
8804 {
8811 }
8812 else
8816 {
8822 {
8825 }
8826 }
8830 {
8834 {
8835 tree attributes
8843 }
8844 }
8846 /* Let's consider the explicit specialization of a member
8847 of a class template specialization that is implicitly instantiated,
8848 e.g.:
8849 template<class T>
8850 struct S
8851 {
8852 template<class U> struct M {}; //#0
8853 };
8855 template<>
8856 template<>
8857 struct S<int>::M<char> //#1
8858 {
8859 int i;
8860 };
8861 [temp.expl.spec]/4 says this is valid.
8863 In this case, when we write:
8864 S<int>::M<char> m;
8866 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8867 the one of #0.
8869 When we encounter #1, we want to store the partial instantiation
8870 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8872 For all cases other than this "explicit specialization of member of a
8873 class template", we just want to store the most general template into
8874 the CLASSTYPE_TI_TEMPLATE of M.
8876 This case of "explicit specialization of member of a class template"
8877 only happens when:
8878 1/ the enclosing class is an instantiation of, and therefore not
8879 the same as, the context of the most general template, and
8880 2/ we aren't looking at the partial instantiation itself, i.e.
8881 the innermost arguments are not the same as the innermost parms of
8882 the most general template.
8884 So it's only when 1/ and 2/ happens that we want to use the partial
8885 instantiation of the member template in lieu of its most general
8886 template. */
8890 /* the enclosing class must be an instantiation... */
8893 {
8897 tree partial_inst_args =
8904 use_partial_inst_tmpl =
8905 /*...and we must not be looking at the partial instantiation
8906 itself. */
8908 partial_inst_args);
8909 }
8912 /* This case is easy; there are no member templates involved. */
8914 else
8915 {
8916 /* This is a full instantiation of a member template. Find
8917 the partial instantiation of which this is an instance. */
8919 /* Temporarily reduce by one the number of levels in the ARGLIST
8920 so as to avoid comparing the last set of arguments. */
8924 /* FOUND is either a proper class type, or an alias
8925 template specialization. In the later case, it's a
8926 TYPE_DECL, resulting from the substituting of arguments
8927 for parameters in the TYPE_DECL of the alias template
8928 done earlier. So be careful while getting the template
8929 of FOUND. */
8931 ? found
8935 }
8937 // Build template info for the new specialization.
8946 /* Note this use of the partial instantiation so we can check it
8947 later in maybe_process_partial_specialization. */
8954 /* Now that the type has been registered on the instantiations
8955 list, we set up the enumerators. Because the enumeration
8956 constants may involve the enumeration type itself, we make
8957 sure to register the type first, and then create the
8958 constants. That way, doing tsubst_expr for the enumeration
8959 constants won't result in recursive calls here; we'll find
8960 the instantiation and exit above. */
8964 /* If the type makes use of template parameters, the
8965 code that generates debugging information will crash. */
8968 /* Possibly limit visibility based on template args. */
8975 }
8976 }
8978 /* Wrapper for lookup_template_class_1. */
8980 tree
8983 {
8984 tree ret;
8990 }
8992 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
8994 tree
8996 {
8997 /* The type of the expression is NULL_TREE since the template-id could refer
8998 to an explicit or partial specialization. */
9001 /* Except that concepts are always bool. */
9004 }
9006 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9008 tree
9010 {
9014 /* We never want to return a VAR_DECL for a variable concept, since they
9015 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9030 {
9032 {
9035 }
9037 }
9039 /* If a template-id refers to a specialization of a variable
9040 concept, then the expression is true if and only if the
9041 concept's constraints are satisfied by the given template
9042 arguments.
9044 NOTE: This is an extension of Concepts Lite TS that
9045 allows constraints to be used in expressions. */
9047 {
9050 }
9053 }
9055 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9056 TARGS template args, and instantiate it if it's not dependent. */
9058 tree
9060 tsubst_flags_t complain)
9061 {
9064 {
9067 }
9070 }
9072 \f
9073 struct pair_fn_data
9074 {
9075 tree_fn_t fn;
9076 tree_fn_t any_fn;
9078 /* True when we should also visit template parameters that occur in
9079 non-deduced contexts. */
9082 };
9084 /* Called from for_each_template_parm via walk_tree. */
9086 static tree
9088 {
9095 #define WALK_SUBTREE(NODE) \
9096 do \
9097 { \
9098 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9099 pfd->include_nondeduced_p, \
9100 pfd->any_fn); \
9101 if (result) goto out; \
9102 } \
9103 while (0)
9113 {
9117 /* Fall through. */
9123 else
9133 /* Since we're not going to walk subtrees, we have to do this
9134 explicitly here. */
9136 /* Fall through. */
9139 /* Check the return type. */
9142 /* Check the parameter types. Since default arguments are not
9143 instantiated until they are needed, the TYPE_ARG_TYPES may
9144 contain expressions that involve template parameters. But,
9145 no-one should be looking at them yet. And, once they're
9146 instantiated, they don't contain template parameters, so
9147 there's no point in looking at them then, either. */
9148 {
9149 tree parm;
9154 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9155 want walk_tree walking into them itself. */
9157 }
9160 {
9164 }
9181 /* Fall through. */
9193 /* Record template parameters such as `T' inside `TT<T>'. */
9195 /* Fall through. */
9207 /* A template template parameter is encountered. */
9211 /* Already substituted template template parameter */
9216 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9217 partial instantiation. */
9229 /* If there's no type, then this thing must be some expression
9230 involving template parameters. */
9252 }
9254 #undef WALK_SUBTREE
9256 /* We didn't find any template parameters we liked. */
9257 out:
9259 }
9261 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9262 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9263 call FN with the parameter and the DATA.
9264 If FN returns nonzero, the iteration is terminated, and
9265 for_each_template_parm returns 1. Otherwise, the iteration
9266 continues. If FN never returns a nonzero value, the value
9267 returned by for_each_template_parm is 0. If FN is NULL, it is
9268 considered to be the function which always returns 1.
9270 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9271 parameters that occur in non-deduced contexts. When false, only
9272 visits those template parameters that can be deduced. */
9274 static tree
9278 tree_fn_t any_fn)
9279 {
9281 tree result;
9283 /* Set up. */
9289 /* Walk the tree. (Conceptually, we would like to walk without
9290 duplicates, but for_each_template_parm_r recursively calls
9291 for_each_template_parm, so we would need to reorganize a fair
9292 bit to use walk_tree_without_duplicates, so we keep our own
9293 visited list.) */
9296 else
9299 for_each_template_parm_r,
9303 /* Clean up. */
9305 {
9308 }
9311 }
9313 /* Returns true if T depends on any template parameter. */
9315 int
9317 {
9347 else
9348 {
9351 }
9356 }
9358 /* Returns true iff current_function_decl is an incompletely instantiated
9359 template. Useful instead of processing_template_decl because the latter
9360 is set to 0 during instantiate_non_dependent_expr. */
9362 bool
9364 {
9373 }
9375 /* Returns true if T depends on any template parameter with level LEVEL. */
9377 bool
9379 {
9382 }
9384 /* Returns true if the signature of DECL depends on any template parameter from
9385 its enclosing class. */
9387 bool
9389 {
9399 template_parm_outer_level,
9409 }
9411 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9412 ill-formed translation unit, i.e. a variable or function that isn't
9413 usable in a constant expression. */
9417 {
9421 }
9423 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9424 neglectable and instantiated from within an erroneous instantiation. */
9426 static bool
9428 {
9439 }
9447 /* We're starting to instantiate D; record the template instantiation context
9448 for diagnostics and to restore it later. */
9450 bool
9452 {
9454 }
9456 /* We're starting to instantiate D; record the template instantiation context
9457 at LOC for diagnostics and to restore it later. */
9459 bool
9461 {
9465 {
9466 /* Tell error.c not to try to instantiate any templates. */
9469 "template instantiation depth exceeds maximum of %d"
9471 max_tinst_depth);
9473 }
9475 /* If the current instantiation caused problems, don't let it instantiate
9476 anything else. Do allow deduction substitution and decls usable in
9477 constant expressions. */
9481 /* When not -quiet, dump template instantiations other than functions, since
9482 announce_function will take care of those. */
9501 }
9503 /* We're done instantiating this template; return to the instantiation
9504 context. */
9506 void
9508 {
9509 /* Restore the filename and line number stashed away when we started
9510 this instantiation. */
9514 }
9516 /* We're instantiating a deferred template; restore the template
9517 instantiation context in which the instantiation was requested, which
9518 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9520 static tree
9522 {
9534 }
9536 /* Returns the TINST_LEVEL which gives the original instantiation
9537 context. */
9541 {
9547 }
9549 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9550 vector of template arguments, as for tsubst.
9552 Returns an appropriate tsubst'd friend declaration. */
9554 static tree
9556 {
9557 tree new_friend;
9562 /* This was a friend declared with an explicit template
9563 argument list, e.g.:
9565 friend void f<>(T);
9567 to indicate that f was a template instantiation, not a new
9568 function declaration. Now, we have to figure out what
9569 instantiation of what template. */
9570 {
9572 tree new_args;
9573 tree tmpl;
9576 /* Friend functions are looked up in the containing namespace scope.
9577 We must enter that scope, to avoid finding member functions of the
9578 current class with same name. */
9593 tsk_none);
9595 }
9599 /* The NEW_FRIEND will look like an instantiation, to the
9600 compiler, but is not an instantiation from the point of view of
9601 the language. For example, we might have had:
9603 template <class T> struct S {
9604 template <class U> friend void f(T, U);
9605 };
9607 Then, in S<int>, template <class U> void f(int, U) is not an
9608 instantiation of anything. */
9614 {
9618 }
9620 /* The mangled name for the NEW_FRIEND is incorrect. The function
9621 is not a template instantiation and should not be mangled like
9622 one. Therefore, we forget the mangling here; we'll recompute it
9623 later if we need it. */
9625 {
9628 }
9631 {
9632 tree old_decl;
9633 tree new_friend_template_info;
9634 tree new_friend_result_template_info;
9635 tree ns;
9638 /* We must save some information from NEW_FRIEND before calling
9639 duplicate decls since that function will free NEW_FRIEND if
9640 possible. */
9642 new_friend_is_defn =
9647 {
9648 /* This declaration is a `primary' template. */
9651 new_friend_result_template_info
9653 }
9654 else
9657 /* Inside pushdecl_namespace_level, we will push into the
9658 current namespace. However, the friend function should go
9659 into the namespace of the template. */
9669 {
9670 /* This new friend declaration matched an existing
9671 declaration. For example, given:
9673 template <class T> void f(T);
9674 template <class U> class C {
9675 template <class T> friend void f(T) {}
9676 };
9678 the friend declaration actually provides the definition
9679 of `f', once C has been instantiated for some type. So,
9680 old_decl will be the out-of-class template declaration,
9681 while new_friend is the in-class definition.
9683 But, if `f' was called before this point, the
9684 instantiation of `f' will have DECL_TI_ARGS corresponding
9685 to `T' but not to `U', references to which might appear
9686 in the definition of `f'. Previously, the most general
9687 template for an instantiation of `f' was the out-of-class
9688 version; now it is the in-class version. Therefore, we
9689 run through all specialization of `f', adding to their
9690 DECL_TI_ARGS appropriately. In particular, they need a
9691 new set of outer arguments, corresponding to the
9692 arguments for this class instantiation.
9694 The same situation can arise with something like this:
9696 friend void f(int);
9697 template <class T> class C {
9698 friend void f(T) {}
9699 };
9701 when `C<int>' is instantiated. Now, `f(int)' is defined
9702 in the class. */
9705 /* On the other hand, if the in-class declaration does
9706 *not* provide a definition, then we don't want to alter
9707 existing definitions. We can just leave everything
9708 alone. */
9709 ;
9710 else
9711 {
9715 /* Overwrite whatever template info was there before, if
9716 any, with the new template information pertaining to
9717 the declaration. */
9721 {
9722 /* We should have called reregister_specialization in
9723 duplicate_decls. */
9728 /* Instantiate it if the global has already been used. */
9732 }
9733 else
9734 {
9735 tree t;
9737 /* Indicate that the old function template is a partial
9738 instantiation. */
9746 /* Reassign any specializations already in the hash table
9747 to the new more general template, and add the
9748 additional template args. */
9752 {
9754 spec_entry elt;
9766 register_specialization
9769 }
9771 }
9772 }
9774 /* The information from NEW_FRIEND has been merged into OLD_DECL
9775 by duplicate_decls. */
9777 }
9778 }
9779 else
9780 {
9784 /* In the code
9785 template <class T> class C {
9786 template <class U> friend void C1<U>::f (); // case 1
9787 friend void C2<T>::f (); // case 2
9788 };
9789 we only need to make sure CONTEXT is a complete type for
9790 case 2. To distinguish between the two cases, we note that
9791 CONTEXT of case 1 remains dependent type after tsubst while
9792 this isn't true for case 2. */
9802 {
9804 /* do_friend adds the TEMPLATE_DECL for any member friend
9805 template even if it isn't a member template, i.e.
9806 template <class T> friend A<T>::f();
9807 Look through it in that case. */
9811 /* Check to see that the declaration is really present, and,
9812 possibly obtain an improved declaration. */
9817 }
9818 }
9821 }
9823 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9824 template arguments, as for tsubst.
9826 Returns an appropriate tsubst'd friend type or error_mark_node on
9827 failure. */
9829 static tree
9831 {
9832 tree friend_type;
9833 tree tmpl;
9834 tree context;
9837 {
9840 }
9845 {
9848 else
9850 }
9852 /* Look for a class template declaration. We look for hidden names
9853 because two friend declarations of the same template are the
9854 same. For example, in:
9856 struct A {
9857 template <typename> friend class F;
9858 };
9859 template <typename> struct B {
9860 template <typename> friend class F;
9861 };
9863 both F templates are the same. */
9867 /* But, if we don't find one, it might be because we're in a
9868 situation like this:
9870 template <class T>
9871 struct S {
9872 template <class U>
9873 friend struct S;
9874 };
9876 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9877 for `S<int>', not the TEMPLATE_DECL. */
9879 {
9882 }
9885 {
9886 /* The friend template has already been declared. Just
9887 check to see that the declarations match, and install any new
9888 default parameters. We must tsubst the default parameters,
9889 of course. We only need the innermost template parameters
9890 because that is all that redeclare_class_template will look
9891 at. */
9894 {
9895 tree parms;
9896 location_t saved_input_location;
9906 }
9909 }
9910 else
9911 {
9912 /* The friend template has not already been declared. In this
9913 case, the instantiation of the template class will cause the
9914 injection of this template into the global scope. */
9919 /* The new TMPL is not an instantiation of anything, so we
9920 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9921 the new type because that is supposed to be the corresponding
9922 template decl, i.e., TMPL. */
9929 /* Inject this template into the global scope. */
9931 }
9934 {
9937 else
9939 }
9942 }
9944 /* Returns zero if TYPE cannot be completed later due to circularity.
9945 Otherwise returns one. */
9947 static int
9949 {
9959 else
9961 }
9966 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
9967 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
9969 static tree
9972 {
9981 {
9988 clauses
9992 else
9994 }
9995 /* If the first attribute argument is an identifier, don't
9996 pass it through tsubst. Attributes like mode, format,
9997 cleanup and several target specific attributes expect it
9998 unmodified. */
10000 {
10001 tree chain
10006 }
10008 {
10009 /* An attribute pack expansion. */
10016 {
10020 }
10022 }
10023 else
10030 }
10032 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10033 unchanged or a new TREE_LIST chain. */
10035 static tree
10038 {
10043 {
10047 }
10051 {
10054 {
10057 {
10059 do
10064 }
10065 }
10067 }
10070 }
10072 /* Apply any attributes which had to be deferred until instantiation
10073 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10074 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10076 static void
10079 {
10081 tree t;
10088 {
10092 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10093 to our attributes parameter. */
10095 }
10096 else
10097 {
10099 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10100 lookup_template_class_1, and should be preserved. */
10104 }
10108 {
10112 }
10116 {
10121 {
10124 {
10128 do
10131 }
10132 else
10134 }
10137 }
10138 }
10140 /* Perform (or defer) access check for typedefs that were referenced
10141 from within the template TMPL code.
10142 This is a subroutine of instantiate_decl and instantiate_class_template.
10143 TMPL is the template to consider and TARGS is the list of arguments of
10144 that template. */
10146 static void
10148 {
10149 location_t saved_location;
10160 {
10172 /* Make access check error messages point to the location
10173 of the use of the typedef. */
10177 tf_warning_or_error);
10178 }
10180 }
10182 static tree
10184 {
10186 tree typedecl;
10187 tree pbinfo;
10188 tree base_list;
10190 tree fn_context;
10199 /* Figure out which template is being instantiated. */
10203 /* Determine what specialization of the original template to
10204 instantiate. */
10207 {
10210 }
10212 {
10213 /* This TYPE is actually an instantiation of a partial
10214 specialization. We replace the innermost set of ARGS with
10215 the arguments appropriate for substitution. For example,
10216 given:
10218 template <class T> struct S {};
10219 template <class T> struct S<T*> {};
10221 and supposing that we are instantiating S<int*>, ARGS will
10222 presently be {int*} -- but we need {int}. */
10225 }
10226 else
10227 {
10230 }
10232 /* If the template we're instantiating is incomplete, then clearly
10233 there's nothing we can do. */
10237 /* If we've recursively instantiated too many templates, stop. */
10241 /* Now we're really doing the instantiation. Mark the type as in
10242 the process of being defined. */
10245 /* We may be in the middle of deferred access check. Disable
10246 it now. */
10253 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10258 else
10259 {
10262 }
10263 /* Use #pragma pack from the template context. */
10269 /* Set the input location to the most specialized template definition.
10270 This is needed if tsubsting causes an error. */
10282 {
10285 /* Adjust visibility for template arguments. */
10287 }
10293 /* We should never instantiate a nested class before its enclosing
10294 class; we need to look up the nested class by name before we can
10295 instantiate it, and that lookup should instantiate the enclosing
10296 class. */
10302 {
10303 tree pbase_binfo;
10304 tree pushed_scope;
10307 /* We must enter the scope containing the type, as that is where
10308 the accessibility of types named in dependent bases are
10309 looked up from. */
10312 /* Substitute into each of the bases to determine the actual
10313 basetypes. */
10315 {
10316 tree base;
10322 {
10323 expanded_bases =
10330 }
10333 {
10335 /* Extract the already-expanded base class. */
10337 else
10338 /* Substitute to figure out the base class. */
10340 NULL_TREE);
10348 }
10349 }
10351 /* The list is now in reverse order; correct that. */
10356 }
10357 /* Now call xref_basetypes to set up all the base-class
10358 information. */
10366 /* Now that our base classes are set up, enter the scope of the
10367 class, so that name lookups into base classes, etc. will work
10368 correctly. This is precisely analogous to what we do in
10369 begin_class_definition when defining an ordinary non-template
10370 class, except we also need to push the enclosing classes. */
10373 /* Now members are processed in the order of declaration. */
10376 {
10380 {
10382 {
10383 /* Build new CLASSTYPE_NESTED_UTDS. */
10385 tree newtag;
10391 /* If the member is a class template, then -- even after
10392 substitution -- there may be dependent types in the
10393 template argument list for the class. We increment
10394 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10395 that function will assume that no types are dependent
10396 when outside of a template. */
10406 {
10410 /* Unfortunately, lookup_template_class sets
10411 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10412 instantiation (i.e., for the type of a member
10413 template class nested within a template class.)
10414 This behavior is required for
10415 maybe_process_partial_specialization to work
10416 correctly, but is not accurate in this case;
10417 the TAG is not an instantiation of anything.
10418 (The corresponding TEMPLATE_DECL is an
10419 instantiation, but the TYPE is not.) */
10422 /* Now, we call pushtag to put this NEWTAG into the scope of
10423 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10424 pushtag calling push_template_decl. We don't have to do
10425 this for enums because it will already have been done in
10426 tsubst_enum. */
10430 }
10431 }
10433 {
10434 /* Build new TYPE_METHODS. */
10435 tree r;
10444 /* Instantiate members marked with attribute used. */
10450 }
10453 /* A closure type for a lambda in a default argument for a
10454 member template. Ignore it; it will be instantiated with
10456 else
10457 {
10458 /* Build new TYPE_FIELDS. */
10460 {
10461 tree condition;
10464 condition =
10474 }
10476 {
10477 tree r;
10481 /* The file and line for this declaration, to
10482 assist in error message reporting. Since we
10483 called push_tinst_level above, we don't need to
10484 restore these. */
10494 {
10495 /* A capture pack became multiple fields. */
10498 }
10501 {
10505 {
10506 /* In [temp.inst]:
10508 [t]he initialization (and any associated
10509 side-effects) of a static data member does
10510 not occur unless the static data member is
10511 itself used in a way that requires the
10512 definition of the static data member to
10513 exist.
10515 Therefore, we do not substitute into the
10516 initialized for the static data member here. */
10517 finish_static_data_member_decl
10523 /* Instantiate members marked with attribute used. */
10526 }
10528 {
10529 /* Determine whether R has a valid type and can be
10530 completed later. If R is invalid, then its type
10531 is replaced by error_mark_node. */
10537 {
10538 /* If R's type couldn't be completed and
10539 it isn't a flexible array member (whose
10540 type is incomplete by definition) give
10541 an error. */
10544 }
10545 }
10547 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10548 such a thing will already have been added to the field
10549 list by tsubst_enum in finish_member_declaration in the
10550 CLASSTYPE_NESTED_UTDS case above. */
10554 {
10557 }
10558 }
10559 }
10560 }
10561 }
10562 else
10563 {
10566 {
10567 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10573 {
10574 /* template <class T> friend class C; */
10577 }
10579 {
10580 /* template <class T> friend class C::D; */
10586 }
10589 {
10590 /* This could be either
10592 friend class T::C;
10594 when dependent_type_p is false or
10596 template <class U> friend class T::C;
10598 otherwise. */
10599 /* Bump processing_template_decl in case this is something like
10600 template <class T> friend struct A<T>::B. */
10607 }
10610 {
10611 /* friend class C;
10613 where C hasn't been declared yet. Let's lookup name
10614 from namespace scope directly, bypassing any name that
10615 come from dependent base class. */
10618 /* The call to xref_tag_from_type does injection for friend
10619 classes. */
10621 friend_type =
10625 }
10627 /* friend class C<T>; */
10630 /* Otherwise it's
10632 friend class C;
10634 where C is already declared or
10636 friend class C<int>;
10638 We don't have to do anything in these cases. */
10641 /* Trick make_friend_class into realizing that the friend
10642 we're adding is a template, not an ordinary class. It's
10643 important that we use make_friend_class since it will
10644 perform some error-checking and output cross-reference
10645 information. */
10653 }
10654 else
10655 {
10656 /* Build new DECL_FRIENDLIST. */
10657 tree r;
10659 /* The file and line for this declaration, to
10660 assist in error message reporting. Since we
10661 called push_tinst_level above, we don't need to
10662 restore these. */
10666 {
10669 }
10674 {
10677 }
10678 }
10679 }
10680 }
10683 {
10684 /* Restore these before substituting into the lambda capture
10685 initializers. */
10688 }
10691 {
10694 {
10700 {
10701 /* Set function_depth to avoid garbage collection. */
10705 }
10707 /* We need to instantiate the capture list from the template
10708 after we've instantiated the closure members, but before we
10709 consider adding the conversion op. Also keep any captures
10710 that may have been added during instantiation of the op(). */
10712 tree tmpl_cap
10721 }
10722 else
10724 }
10726 /* Set the file and line number information to whatever is given for
10727 the class itself. This puts error messages involving generated
10728 implicit functions at a predictable point, and the same point
10729 that would be used for non-template classes. */
10736 /* We don't instantiate default arguments for member functions. 14.7.1:
10738 The implicit instantiation of a class template specialization causes
10739 the implicit instantiation of the declarations, but not of the
10740 definitions or default arguments, of the class member functions,
10741 member classes, static data members and member templates.... */
10743 /* Some typedefs referenced from within the template code need to be access
10744 checked at template instantiation time, i.e now. These types were
10745 added to the template at parsing time. Let's get those and perform
10746 the access checks then. */
10756 /* The vtable for a template class can be emitted in any translation
10757 unit in which the class is instantiated. When there is no key
10758 method, however, finish_struct_1 will already have added TYPE to
10759 the keyed_classes list. */
10764 }
10766 /* Wrapper for instantiate_class_template_1. */
10768 tree
10770 {
10771 tree ret;
10776 }
10778 static tree
10780 {
10781 tree r;
10787 else
10788 {
10795 }
10797 }
10799 /* Given a function parameter pack TMPL_PARM and some function parameters
10800 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10801 and set *SPEC_P to point at the next point in the list. */
10803 tree
10805 {
10806 /* Collect all of the extra "packed" parameters into an
10807 argument pack. */
10808 tree parmvec;
10809 tree parmtypevec;
10820 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10825 {
10828 }
10830 /* Build the argument packs. */
10837 }
10839 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10840 NONTYPE_ARGUMENT_PACK. */
10842 static tree
10844 {
10846 }
10848 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10849 pack expansion with no extra args, 2 if it has extra args, or 0
10850 if it is not a pack expansion. */
10852 static int
10854 {
10860 /* A decl pack is itself an expansion. */
10867 }
10870 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10872 static tree
10874 {
10881 }
10883 /* This is a subroutine of tsubst_pack_expansion.
10885 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10886 mechanism to store the (non complete list of) arguments of the
10887 substitution and return a non substituted pack expansion, in order
10888 to wait for when we have enough arguments to really perform the
10889 substitution. */
10891 static bool
10895 {
10896 /* If one pack has an expansion and another pack has a normal
10897 argument or if one pack has an empty argument and an another
10898 one hasn't then tsubst_pack_expansion cannot perform the
10899 substitution and need to fall back on the
10900 PACK_EXPANSION_EXTRA mechanism. */
10908 {
10911 parm_pack;
10913 {
10918 /* We can't substitute a pack expansion with extra args into
10919 our pattern. */
10923 else
10925 }
10929 }
10931 }
10933 /* [temp.variadic]/6 says that:
10935 The instantiation of a pack expansion [...]
10936 produces a list E1,E2, ..., En, where N is the number of elements
10937 in the pack expansion parameters.
10939 This subroutine of tsubst_pack_expansion produces one of these Ei.
10941 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10942 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10943 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10944 INDEX is the index 'i' of the element Ei to produce. ARGS,
10945 COMPLAIN, and IN_DECL are the same parameters as for the
10946 tsubst_pack_expansion function.
10948 The function returns the resulting Ei upon successful completion,
10949 or error_mark_node.
10951 Note that this function possibly modifies the ARGS parameter, so
10952 it's the responsibility of the caller to restore it. */
10954 static tree
10956 tree parm_packs,
10958 tree args /* This parm gets
10960 tsubst_flags_t complain,
10961 tree in_decl)
10962 {
10963 tree t;
10966 /* For each parameter pack, change the substitution of the parameter
10967 pack to the ith argument in its argument pack, then expand the
10968 pattern. */
10970 {
10975 ith_elem_is_expansion |=
10978 /* Select the Ith argument from the pack. */
10981 {
10983 {
10988 }
10989 else
10991 }
10992 else
10993 {
10998 {
11000 /* Update the corresponding argument. */
11002 }
11003 else
11004 /* Re-use the ARGUMENT_PACK_SELECT. */
11006 }
11008 }
11010 /* Substitute into the PATTERN with the (possibly altered)
11011 arguments. */
11013 /* Expanding a fixed parameter pack from
11014 coerce_template_parameter_pack. */
11019 {
11022 else
11025 }
11029 else
11032 /* If the Ith argument pack element is a pack expansion, then
11033 the Ith element resulting from the substituting is going to
11034 be a pack expansion as well. */
11039 }
11041 /* When the unexpanded parameter pack in a fold expression expands to an empty
11042 sequence, the value of the expression is as follows; the program is
11043 ill-formed if the operator is not listed in this table.
11045 && true
11046 || false
11047 , void() */
11049 tree
11051 {
11055 {
11064 }
11070 }
11072 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11073 form an expression that combines the two terms using the
11074 operator of T. */
11076 static tree
11078 {
11082 // Handle compound assignment operators.
11087 {
11097 complain);
11098 }
11099 }
11101 /* Substitute ARGS into the pack of a fold expression T. */
11105 {
11107 }
11109 /* Substitute ARGS into the pack of a fold expression T. */
11113 {
11115 }
11117 /* Expand a PACK of arguments into a grouped as left fold.
11118 Given a pack containing elements A0, A1, ..., An and an
11119 operator @, this builds the expression:
11121 ((A0 @ A1) @ A2) ... @ An
11123 Note that PACK must not be empty.
11125 The operator is defined by the original fold expression T. */
11127 static tree
11129 {
11132 {
11135 }
11137 }
11139 /* Substitute into a unary left fold expression. */
11141 static tree
11143 tree in_decl)
11144 {
11149 {
11153 }
11156 else
11158 }
11160 /* Substitute into a binary left fold expression.
11162 Do ths by building a single (non-empty) vector of argumnts and
11163 building the expression from those elements. */
11165 static tree
11167 tree in_decl)
11168 {
11177 {
11182 }
11190 }
11192 /* Expand a PACK of arguments into a grouped as right fold.
11193 Given a pack containing elementns A0, A1, ..., and an
11194 operator @, this builds the expression:
11196 A0@ ... (An-2 @ (An-1 @ An))
11198 Note that PACK must not be empty.
11200 The operator is defined by the original fold expression T. */
11202 tree
11204 {
11205 // Build the expression.
11209 {
11212 }
11214 }
11216 /* Substitute into a unary right fold expression. */
11218 static tree
11220 tree in_decl)
11221 {
11226 {
11230 }
11233 else
11235 }
11237 /* Substitute into a binary right fold expression.
11239 Do ths by building a single (non-empty) vector of arguments and
11240 building the expression from those elements. */
11242 static tree
11244 tree in_decl)
11245 {
11254 {
11259 }
11268 }
11271 /* Substitute ARGS into T, which is an pack expansion
11272 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11273 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11274 (if only a partial substitution could be performed) or
11275 ERROR_MARK_NODE if there was an error. */
11276 tree
11278 tree in_decl)
11279 {
11280 tree pattern;
11284 tree result;
11292 /* Add in any args remembered from an earlier partial instantiation. */
11297 /* Determine the argument packs that will instantiate the parameter
11298 packs used in the expansion expression. While we're at it,
11299 compute the number of arguments to be expanded and make sure it
11300 is consistent. */
11303 {
11310 {
11314 else
11317 }
11319 {
11320 /* We know we have correct local_specializations if this
11321 expansion is at function scope, or if we're dealing with a
11322 local parameter in a requires expression; for the latter,
11323 tsubst_requires_expr set it up appropriately. */
11326 else
11327 /* We can't rely on local_specializations for a parameter
11328 name used later in a function declaration (such as in a
11329 late-specified return type). Even if it exists, it might
11330 have the wrong value for a recursive call. */
11334 {
11335 /* This parameter pack was used in an unevaluated context. Just
11336 make a dummy decl, since it's only used for its type. */
11339 /* Partial instantiation of the parm_pack, we can't build
11340 up an argument pack yet. */
11342 else
11344 }
11345 }
11348 else
11349 {
11355 }
11362 /* This can only happen if we forget to expand an argument
11363 pack somewhere else. Just return an error, silently. */
11364 {
11368 }
11371 {
11375 /* Don't bother trying to do a partial substitution with
11376 incomplete packs; we'll try again after deduction. */
11383 {
11389 pattern);
11390 else
11393 pattern);
11395 }
11397 /* Keep track of the parameter packs and their corresponding
11398 argument packs. */
11401 }
11402 else
11403 {
11404 /* We can't substitute for this parameter pack. We use a flag as
11405 well as the missing_level counter because function parameter
11406 packs don't have a level. */
11409 }
11410 }
11412 /* If the expansion is just T..., return the matching argument pack, unless
11413 we need to call convert_from_reference on all the elements. This is an
11414 important optimization; see c++/68422. */
11417 {
11419 /* Types need no adjustment, nor does sizeof..., and if we still have
11420 some pack expansion args we won't do anything yet. */
11425 /* Also optimize expression pack expansions if we can tell that the
11426 elements won't have reference type. */
11432 /* Otherwise use the normal path so we get convert_from_reference. */
11433 }
11435 /* We cannot expand this expansion expression, because we don't have
11436 all of the argument packs we need. */
11438 {
11439 /* We got some full packs, but we can't substitute them in until we
11440 have values for all the packs. So remember these until then. */
11445 }
11447 {
11448 /* There were no real arguments, we're just replacing a parameter
11449 pack with another version of itself. Substitute into the
11450 pattern and return a PACK_EXPANSION_*. The caller will need to
11451 deal with that. */
11455 else
11459 }
11464 {
11465 /* We're in a late-specified return type, so create our own local
11466 specializations map; the current map is either NULL or (in the
11467 case of recursive unification) might have bindings that we don't
11468 want to use or alter. */
11471 }
11473 /* For each argument in each argument pack, substitute into the
11474 pattern. */
11478 {
11480 i,
11482 in_decl);
11485 {
11488 }
11489 }
11491 /* Update ARGS to restore the substitution from parameter packs to
11492 their argument packs. */
11494 {
11500 else
11501 {
11509 /* Update the corresponding argument. */
11513 else
11515 }
11516 }
11519 {
11522 }
11524 /* If the dependent pack arguments were such that we end up with only a
11525 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11531 }
11533 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11534 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11535 parameter packs; all parms generated from a function parameter pack will
11536 have the same DECL_PARM_INDEX. */
11538 tree
11540 {
11542 tree patparm;
11545 {
11551 }
11552 else
11553 {
11558 }
11561 }
11563 /* Make an argument pack out of the TREE_VEC VEC. */
11565 static tree
11567 {
11568 tree pack;
11572 else
11573 {
11577 }
11580 }
11582 /* Return an exact copy of template args T that can be modified
11583 independently. */
11585 static tree
11587 {
11595 {
11600 }
11606 }
11608 /* Substitute ARGS into the vector or list of template arguments T. */
11610 static tree
11612 {
11624 {
11626 tree new_arg;
11631 {
11632 /* Substitute into an expansion expression. */
11636 /* Add to the expanded length adjustment the number of
11637 expanded arguments. We subtract one from this
11638 measurement, because the argument pack expression
11639 itself is already counted as 1 in
11640 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11641 the argument pack is empty. */
11643 }
11645 {
11646 /* Substitute into each of the arguments. */
11652 new_arg,
11662 else
11669 }
11670 }
11671 else
11680 }
11685 /* Make space for the expanded arguments coming from template
11686 argument packs. */
11688 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11689 arguments for a member template.
11690 In that case each TREE_VEC in ORIG_T represents a level of template
11691 arguments, and ORIG_T won't carry any non defaulted argument count.
11692 It will rather be the nested TREE_VECs that will carry one.
11693 In other words, ORIG_T carries a non defaulted argument count only
11694 if it doesn't contain any nested TREE_VEC. */
11696 {
11700 }
11702 {
11706 {
11709 /* Now expand the template argument pack "in place". */
11712 }
11713 else
11714 {
11716 out++;
11717 }
11718 }
11721 }
11723 /* Substitute ARGS into one level PARMS of template parameters. */
11725 static tree
11727 {
11734 {
11742 }
11745 }
11747 /* Return the result of substituting ARGS into the template parameters
11748 given by PARMS. If there are m levels of ARGS and m + n levels of
11749 PARMS, then the result will contain n levels of PARMS. For
11750 example, if PARMS is `template <class T> template <class U>
11751 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11752 result will be `template <int*, double, class V>'. */
11754 static tree
11756 {
11760 /* When substituting into a template, we must set
11761 PROCESSING_TEMPLATE_DECL as the template parameters may be
11762 dependent if they are based on one-another, and the dependency
11763 predicates are short-circuit outside of templates. */
11770 {
11777 }
11782 }
11784 /* Return the result of substituting ARGS into one template parameter
11785 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11786 parameter and which TREE_PURPOSE is the default argument of the
11787 template parameter. */
11789 static tree
11791 {
11812 }
11814 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11815 type T. If T is not an aggregate or enumeration type, it is
11816 handled as if by tsubst. IN_DECL is as for tsubst. If
11817 ENTERING_SCOPE is nonzero, T is the context for a template which
11818 we are presently tsubst'ing. Return the substituted value. */
11820 static tree
11822 tree args,
11823 tsubst_flags_t complain,
11824 tree in_decl,
11826 {
11831 {
11836 /* Fall through. */
11840 {
11841 tree argvec;
11842 tree context;
11843 tree r;
11847 /* In "sizeof(X<I>)" we need to evaluate "I". */
11853 /* First, determine the context for the type we are looking
11854 up. */
11857 {
11860 /* If context is a nested class inside a class template,
11861 it may still need to be instantiated (c++/33959). */
11863 }
11865 /* Then, figure out what arguments are appropriate for the
11866 type we are trying to find. For example, given:
11868 template <class T> struct S;
11869 template <class T, class U> void f(T, U) { S<U> su; }
11871 and supposing that we are instantiating f<int, double>,
11872 then our ARGS will be {int, double}, but, when looking up
11873 S we only want {double}. */
11878 else
11879 {
11883 }
11889 }
11890 else
11891 /* This is not a template type, so there's nothing to do. */
11896 }
11897 }
11899 /* Substitute into the default argument ARG (a default argument for
11900 FN), which has the indicated TYPE. */
11902 tree
11904 {
11909 /* This can happen in invalid code. */
11913 /* This default argument came from a template. Instantiate the
11914 default argument here, not in tsubst. In the case of
11915 something like:
11917 template <class T>
11918 struct S {
11919 static T t();
11920 void f(T = t());
11921 };
11923 we must be careful to do name lookup in the scope of S<T>,
11924 rather than in the current class. */
11926 /* The "this" pointer is not valid in a default argument. */
11928 {
11933 }
11936 /* The default argument expression may cause implicitly defined
11937 member functions to be synthesized, which will result in garbage
11938 collection. We must treat this situation as if we were within
11939 the body of function so as to avoid collecting live data on the
11940 stack. */
11948 /* Restore the "this" pointer. */
11950 {
11953 }
11960 /* Make sure the default argument is reasonable. */
11966 }
11968 /* Substitute into all the default arguments for FN. */
11970 static void
11972 {
11973 tree arg;
11974 tree tmpl_args;
11978 /* If this function is not yet instantiated, we certainly don't need
11979 its default arguments. */
11982 /* Don't do this again for clones. */
11987 arg;
11993 complain);
11994 }
11996 /* Substitute the ARGS into the T, which is a _DECL. Return the
11997 result of the substitution. Issue error and warning messages under
11998 control of COMPLAIN. */
12000 static tree
12002 {
12003 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12004 location_t saved_loc;
12009 /* Set the filename and linenumber to improve error-reporting. */
12014 {
12016 {
12017 /* We can get here when processing a member function template,
12018 member class template, or template template parameter. */
12020 tree spec;
12021 tree tmpl_args;
12022 tree full_args;
12025 {
12026 /* Template template parameter is treated here. */
12030 /* If we get a real template back, return it. This can happen in
12031 the context of most_specialized_partial_spec. */
12034 else
12035 /* The new TEMPLATE_DECL was built in
12036 reduce_template_parm_level. */
12039 }
12041 /* We might already have an instance of this template.
12042 The ARGS are for the surrounding class type, so the
12043 full args contain the tsubst'd args for the context,
12044 plus the innermost args from the template decl. */
12048 /* Because this is a template, the arguments will still be
12049 dependent, even after substitution. If
12050 PROCESSING_TEMPLATE_DECL is not set, the dependency
12051 predicates will short-circuit. */
12059 /* If this is a default template template argument,
12060 tsubst might not have changed anything. */
12067 {
12070 }
12072 /* Make a new template decl. It will be similar to the
12073 original, but will record the current template arguments.
12074 We also create a new function declaration, which is just
12075 like the old one, but points to this new template, rather
12076 than the old one. */
12081 // Build new template info linking to the original template decl.
12086 {
12087 tree new_type;
12095 /* For a partial specialization, we need to keep pointing to
12096 the primary template. */
12102 }
12103 else
12104 {
12105 tree new_decl;
12117 }
12123 /* The template parameters for this new template are all the
12124 template parameters for the old template, except the
12125 outermost level of parameters. */
12128 complain);
12134 /* Record this non-type partial instantiation. */
12138 }
12142 {
12143 tree ctx;
12146 tree gen_tmpl;
12147 tree type;
12152 /* Nobody should be tsubst'ing into non-template functions. */
12156 {
12157 tree spec;
12159 /* If T is not dependent, just return it. */
12163 /* Calculate the most general template of which R is a
12164 specialization, and the complete set of arguments used to
12165 specialize R. */
12168 (DECL_TEMPLATE_RESULT
12174 /* Check to see if we already have this specialization. */
12179 {
12182 }
12184 /* We can see more levels of arguments than parameters if
12185 there was a specialization of a member template, like
12186 this:
12188 template <class T> struct S { template <class U> void f(); }
12189 template <> template <class U> void S<int>::f(U);
12191 Here, we'll be substituting into the specialization,
12192 because that's where we can find the code we actually
12193 want to generate, but we'll have enough arguments for
12194 the most general template.
12196 We also deal with the peculiar case:
12198 template <class T> struct S {
12199 template <class U> friend void f();
12200 };
12201 template <class U> void f() {}
12202 template S<int>;
12203 template void f<double>();
12205 Here, the ARGS for the instantiation of will be {int,
12206 double}. But, we only need as many ARGS as there are
12207 levels of template parameters in CODE_PATTERN. We are
12208 careful not to get fooled into reducing the ARGS in
12209 situations like:
12211 template <class T> struct S { template <class U> void f(U); }
12212 template <class T> template <> void S<T>::f(int) {}
12214 which we can spot because the pattern will be a
12215 specialization in this case. */
12217 parms_depth =
12222 }
12223 else
12224 {
12225 /* This special case arises when we have something like this:
12227 template <class T> struct S {
12228 friend void f<int>(int, double);
12229 };
12231 Here, the DECL_TI_TEMPLATE for the friend declaration
12232 will be an IDENTIFIER_NODE. We are being called from
12233 tsubst_friend_function, and we want only to create a
12234 new decl (R) with appropriate types so that we can call
12235 determine_specialization. */
12237 }
12240 {
12243 else
12247 }
12248 else
12249 {
12252 }
12257 /* If we hit excessive deduction depth, the type is bogus even if
12258 it isn't error_mark_node, so don't build a decl. */
12262 /* We do NOT check for matching decls pushed separately at this
12263 point, as they may not represent instantiations of this
12264 template, and in any case are considered separate under the
12265 discrete model. */
12269 /* Clear out the mangled name and RTL for the instantiation. */
12272 /* Leave DECL_INITIAL set on deleted instantiations. */
12277 /* OpenMP UDRs have the only argument a reference to the declared
12278 type. We want to diagnose if the declared type is a reference,
12279 which is invalid, but as references to references are usually
12280 quietly merged, diagnose it here. */
12282 {
12283 tree argtype
12288 "reference type %qT in "
12292 argtype);
12293 }
12296 /* Type-conversion operator. Reconstruct the name, in
12297 case it's the name of one of the template's parameters. */
12307 /* If this is an instantiation of a function with internal
12308 linkage, we already know what object file linkage will be
12309 assigned to the instantiation. */
12318 /* We'll re-clone as appropriate in instantiate_template. */
12321 /* If we aren't complaining now, return on error before we register
12322 the specialization so that we'll complain eventually. */
12328 /* When instantiating a constrained member, substitute
12329 into the constraints to create a new constraint. */
12332 {
12335 }
12337 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12338 this in the special friend case mentioned above where
12339 GEN_TMPL is NULL. */
12341 {
12346 tree new_r
12349 /* We instantiated this while substituting into
12350 the type earlier (template/friend54.C). */
12353 /* We're not supposed to instantiate default arguments
12354 until they are called, for a template. But, for a
12355 declaration like:
12357 template <class T> void f ()
12358 { extern void g(int i = T()); }
12360 we should do the substitution when the template is
12361 instantiated. We handle the member function case in
12362 instantiate_class_template since the default arguments
12363 might refer to other members of the class. */
12368 }
12369 else
12372 /* Copy the list of befriending classes. */
12376 {
12380 in_decl);
12381 }
12384 {
12388 /* If this is an instantiation of a member template, clone it.
12389 If it isn't, that'll be handled by
12390 clone_constructors_and_destructors. */
12393 }
12404 /* Possibly limit visibility based on template args. */
12407 {
12411 }
12419 }
12423 {
12431 {
12432 /* If there is a local specialization that isn't a
12433 parameter pack, it means that we're doing a "simple"
12434 substitution from inside tsubst_pack_expansion. Just
12435 return the local specialization (which will be a single
12436 parm). */
12443 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12444 the parameters in this function parameter pack. */
12448 {
12451 /* Zero-length parameter packs are boring. Just substitute
12452 into the chain. */
12456 }
12457 else
12458 {
12459 /* All we did was update the type. Make a note of that. */
12462 }
12463 }
12465 /* Loop through all of the parameters we'll build. When T is
12466 a function parameter pack, LEN is the number of expanded
12467 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12470 {
12477 /* We're on the Ith parameter of the function parameter
12478 pack. */
12479 {
12480 /* Get the Ith type. */
12483 /* Rename the parameter to include the index. */
12486 }
12488 /* We're dealing with a normal parameter. */
12496 {
12499 else
12502 }
12512 /* Keep track of the first new parameter we
12513 generate. That's what will be returned to the
12514 caller. */
12518 /* Build a proper chain of parameters when substituting
12519 into a function parameter pack. */
12522 }
12524 /* If cp_unevaluated_operand is set, we're just looking for a
12525 single dummy parameter, so don't keep going. */
12530 /* FIRST_R contains the start of the chain we've built. */
12532 }
12536 {
12543 {
12544 /* This field is a lambda capture pack. Return a TREE_VEC of
12545 the expanded fields to instantiate_class_template_1 and
12546 store them in the specializations hash table as a
12547 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12551 {
12554 }
12555 else
12556 {
12557 /* All we did was update the type. Make a note of that. */
12560 }
12561 }
12564 {
12567 {
12571 }
12581 /* For bit-fields, DECL_INITIAL gives the number of bits. For
12582 non-bit-fields DECL_INITIAL is a non-static data member
12583 initializer, which gets deferred instantiation. */
12589 {
12590 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12591 NSDMI in perform_member_init. Still set DECL_INITIAL
12592 so that we know there is one. */
12597 }
12598 /* We don't have to set DECL_CONTEXT here; it is set by
12599 finish_member_declaration. */
12607 }
12610 {
12618 }
12619 }
12623 /* We reach here only for member using decls. We also need to check
12624 uses_template_parms because DECL_DEPENDENT_P is not set for a
12625 using-declaration that designates a member of the current
12626 instantiation (c++/53549). */
12629 {
12633 {
12638 {
12642 {
12645 }
12646 else
12647 {
12650 }
12652 }
12653 }
12654 else
12655 {
12661 else
12662 {
12665 }
12666 }
12667 }
12668 else
12669 {
12672 }
12677 {
12680 tree spec;
12682 tree ctx;
12691 {
12692 /* If this is the canonical decl, we don't have to
12693 mess with instantiations, and often we can't (for
12694 typename, template type parms and such). Note that
12695 TYPE_NAME is not correct for the above test if
12696 we've copied the type for a typedef. */
12702 }
12704 /* Check to see if we already have the specialization we
12705 need. */
12708 {
12709 /* T is a static data member or namespace-scope entity.
12710 We have to substitute into namespace-scope variables
12711 (not just variable templates) because of cases like:
12713 template <class T> void f() { extern T t; }
12715 where the entity referenced is not known until
12716 instantiation time. */
12720 {
12722 complain,
12724 /* If CTX is unchanged, then T is in fact the
12725 specialization we want. That situation occurs when
12726 referencing a static data member within in its own
12727 class. We can use pointer equality, rather than
12728 same_type_p, because DECL_CONTEXT is always
12729 canonical... */
12731 /* ... unless T is a member template; in which
12732 case our caller can be willing to create a
12733 specialization of that template represented
12734 by T. */
12738 }
12741 {
12746 argvec = (coerce_innermost_template_parms
12754 }
12755 }
12756 else
12757 {
12758 /* A local variable. */
12760 /* Subsequent calls to pushdecl will fill this in. */
12762 /* Unless this is a reference to a static variable from an
12763 enclosing function, in which case we need to fill it in now. */
12765 {
12769 }
12771 }
12772 /* If we already have the specialization we need, there is
12773 nothing more to do. */
12775 {
12778 }
12780 /* Create a new node for the specialization we need. */
12783 {
12786 else
12793 }
12795 {
12796 /* Even if the original location is out of scope, the
12797 newly substituted one is not. */
12804 {
12805 /* It may seem that this case cannot occur, since:
12807 typedef void f();
12808 void g() { f x; }
12810 declares a function, not a variable. However:
12812 typedef void f();
12813 template <typename T> void g() { T t; }
12814 template void g<f>();
12816 is an attempt to declare a variable with function
12817 type. */
12819 /* R is not yet sufficiently initialized, so we
12820 just use its name. */
12823 }
12825 /* Wait until cp_finish_decl to set this again, to handle
12826 circular dependency (template/instantiate6.C). */
12831 {
12836 {
12839 }
12841 }
12845 }
12851 /* Clear out the mangled name and RTL for the instantiation. */
12855 /* The initializer must not be expanded until it is required;
12856 see [temp.inst]. */
12864 {
12865 /* Possibly limit visibility based on template args. */
12868 {
12872 }
12874 }
12877 {
12878 /* A static data member declaration is always marked
12879 external when it is declared in-class, even if an
12880 initializer is present. We mimic the non-template
12881 processing here. */
12889 }
12890 else
12891 {
12896 }
12904 /* Preserve a typedef that names a type. */
12906 {
12910 /* An alias template specialization can be dependent
12911 even if its underlying type is not. */
12913 }
12916 }
12921 }
12922 #undef RETURN
12924 out:
12925 /* Restore the file and line information. */
12929 }
12931 /* Substitute into the ARG_TYPES of a function type.
12932 If END is a TREE_CHAIN, leave it and any following types
12933 un-substituted. */
12935 static tree
12937 tree args,
12938 tree end,
12939 tsubst_flags_t complain,
12940 tree in_decl)
12941 {
12942 tree remaining_arg_types;
12946 tree default_arg;
12957 {
12958 /* For a pack expansion, perform substitution on the
12959 entire expression. Later on, we'll handle the arguments
12960 one-by-one. */
12965 /* So that we'll spin through the parameters, one by one. */
12967 else
12968 {
12969 /* We only partially substituted into the parameter
12970 pack. Our type is TYPE_PACK_EXPANSION. */
12973 }
12974 }
12987 {
12989 {
12993 }
12995 }
12996 /* DR 657. */
13000 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13001 top-level qualifiers as required. */
13004 /* We do not substitute into default arguments here. The standard
13005 mandates that they be instantiated only when needed, which is
13006 done in build_over_call. */
13010 {
13011 /* We've instantiated a template before its default arguments
13012 have been parsed. This can happen for a nested template
13013 class, and is not an error unless we require the default
13014 argument in a call of this function. */
13015 remaining_arg_types =
13018 }
13019 else
13020 remaining_arg_types =
13022 }
13025 }
13027 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13028 *not* handle the exception-specification for FNTYPE, because the
13029 initial substitution of explicitly provided template parameters
13030 during argument deduction forbids substitution into the
13031 exception-specification:
13033 [temp.deduct]
13035 All references in the function type of the function template to the
13036 corresponding template parameters are replaced by the specified tem-
13037 plate argument values. If a substitution in a template parameter or
13038 in the function type of the function template results in an invalid
13039 type, type deduction fails. [Note: The equivalent substitution in
13040 exception specifications is done only when the function is instanti-
13041 ated, at which point a program is ill-formed if the substitution
13042 results in an invalid type.] */
13044 static tree
13046 tree args,
13047 tsubst_flags_t complain,
13048 tree in_decl)
13049 {
13050 tree return_type;
13052 tree fntype;
13054 /* The TYPE_CONTEXT is not used for function/method types. */
13057 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13058 failure. */
13062 {
13063 /* Substitute the argument types. */
13075 {
13076 /* DR 1207: 'this' is in scope in the trailing return type. */
13078 }
13080 /* Substitute the return type. */
13084 {
13087 }
13088 }
13089 else
13090 /* Substitute the return type. */
13095 /* DR 486 clarifies that creation of a function type with an
13096 invalid return type is a deduction failure. */
13099 {
13101 {
13104 else
13106 }
13108 }
13109 /* And DR 657. */
13114 {
13115 /* Substitute the argument types. */
13120 }
13122 /* Construct a new type node and return it. */
13124 {
13129 }
13130 else
13131 {
13133 /* Don't pick up extra function qualifiers from the basetype. */
13136 {
13137 /* [temp.deduct]
13139 Type deduction may fail for any of the following
13140 reasons:
13142 -- Attempting to create "pointer to member of T" when T
13143 is not a class type. */
13146 r);
13148 }
13153 }
13160 }
13162 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13163 ARGS into that specification, and return the substituted
13164 specification. If there is no specification, return NULL_TREE. */
13166 static tree
13168 tree args,
13169 tsubst_flags_t complain,
13170 tree in_decl,
13172 {
13173 tree specs;
13174 tree new_specs;
13179 {
13180 /* A noexcept-specifier. */
13185 {
13186 /* Defer instantiation of noexcept-specifiers to avoid
13187 excessive instantiations (c++/49107). */
13190 {
13191 /* We already partially instantiated this member template,
13192 so combine the new args with the old. */
13197 }
13198 else
13199 {
13202 }
13203 }
13204 else
13205 new_specs = tsubst_copy_and_build
13209 }
13211 {
13214 else
13216 {
13217 tree spec;
13222 {
13223 /* Expand the pack expansion type. */
13226 in_decl);
13232 else
13233 {
13234 /* We're substituting into a member template, so
13235 we got a TYPE_PACK_EXPANSION back. Add that
13236 expansion and move on. */
13240 expanded_specs,
13241 complain);
13244 }
13245 }
13248 {
13251 else
13256 complain);
13257 }
13260 }
13261 }
13263 }
13265 /* Take the tree structure T and replace template parameters used
13266 therein with the argument vector ARGS. IN_DECL is an associated
13267 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13268 Issue error and warning messages under control of COMPLAIN. Note
13269 that we must be relatively non-tolerant of extensions here, in
13270 order to preserve conformance; if we allow substitutions that
13271 should not be allowed, we may allow argument deductions that should
13272 not succeed, and therefore report ambiguous overload situations
13273 where there are none. In theory, we could allow the substitution,
13274 but indicate that it should have failed, and allow our caller to
13275 make sure that the right thing happens, but we don't try to do this
13276 yet.
13278 This function is used for dealing with types, decls and the like;
13279 for expressions, use tsubst_expr or tsubst_copy. */
13281 tree
13283 {
13306 else
13311 /* Reuse typedefs. We need to do this to handle dependent attributes,
13312 such as attribute aligned. */
13315 {
13319 {
13320 /* DECL represents an alias template and we want to
13321 instantiate it. */
13325 }
13329 {
13333 }
13338 else
13339 /* The typedef is from a non-template context. */
13343 {
13345 r = cp_build_qualified_type_real
13349 }
13350 else
13351 {
13352 /* We don't have an instantiation yet, so drop the typedef. */
13357 }
13358 }
13374 {
13400 {
13406 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13407 needed. */
13413 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13414 with TREE_SIDE_EFFECTS that indicates this is not an integral
13415 constant expression. */
13418 {
13421 }
13424 }
13430 {
13436 /* Early in template argument deduction substitution, we don't
13437 want to reduce the level of 'auto', or it will be confused
13438 with a normal template parm in subsequent deduction. */
13450 {
13454 {
13455 /* See through ARGUMENT_PACK_SELECT arguments. */
13457 /* If the selected argument is an expansion E, that most
13458 likely means we were called from
13459 gen_elem_of_pack_expansion_instantiation during the
13460 substituting of pack an argument pack (which Ith
13461 element is a pack expansion, where I is
13462 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13463 In this case, the Ith element resulting from this
13464 substituting is going to be a pack expansion, which
13465 pattern is the pattern of E. Let's return the
13466 pattern of E, and
13467 gen_elem_of_pack_expansion_instantiation will
13468 build the resulting pack expansion from it. */
13470 {
13471 /* Make sure we aren't throwing away arg info. */
13474 }
13475 }
13476 }
13481 {
13483 /* If ARG is an argument pack, we don't actually want to
13484 perform a substitution here, because substitutions
13485 for argument packs are only done
13486 element-by-element. We can get to this point when
13487 substituting the type of a non-type template
13488 parameter pack, when that type actually contains
13489 template parameter packs from an outer template, e.g.,
13491 template<typename... Types> struct A {
13492 template<Types... Values> struct B { };
13493 }; */
13497 {
13503 return cp_build_qualified_type_real
13505 }
13507 {
13508 /* We are processing a type constructed from a
13509 template template parameter. */
13520 /* Consider this code:
13522 template <template <class> class Template>
13523 struct Internal {
13524 template <class Arg> using Bind = Template<Arg>;
13525 };
13527 template <template <class> class Template, class Arg>
13528 using Instantiate = Template<Arg>; //#0
13530 template <template <class> class Template,
13531 class Argument>
13532 using Bind =
13533 Instantiate<Internal<Template>::template Bind,
13534 Argument>; //#1
13536 When #1 is parsed, the
13537 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13538 parameter `Template' in #0 matches the
13539 UNBOUND_CLASS_TEMPLATE representing the argument
13540 `Internal<Template>::template Bind'; We then want
13541 to assemble the type `Bind<Argument>' that can't
13542 be fully created right now, because
13543 `Internal<Template>' not being complete, the Bind
13544 template cannot be looked up in that context. So
13545 we need to "store" `Bind<Argument>' for later
13546 when the context of Bind becomes complete. Let's
13547 store that in a TYPENAME_TYPE. */
13551 argvec),
13552 typename_type,
13553 complain);
13555 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13556 are resolving nested-types in the signature of a
13557 member function templates. Otherwise ARG is a
13558 TEMPLATE_DECL and is the real template to be
13559 instantiated. */
13567 complain);
13568 return cp_build_qualified_type_real
13570 }
13573 else
13574 /* TEMPLATE_PARM_INDEX. */
13576 }
13579 /* This can happen during the attempted tsubst'ing in
13580 unify. This means that we don't yet have any information
13581 about the template parameter in question. */
13584 /* If we get here, we must have been looking at a parm for a
13585 more deeply nested template. Make a new version of this
13586 template parameter, but with a lower level. */
13588 {
13593 {
13595 r = cp_build_qualified_type_real
13599 }
13606 /* Break infinite recursion when substituting the constraints
13608 else
13609 {
13620 {
13621 /* Propagate constraints on placeholders. */
13626 {
13630 }
13631 }
13634 /* We have reduced the level of the template
13635 template parameter, but not the levels of its
13636 template parameters, so canonical_type_parameter
13637 will not be able to find the canonical template
13638 template parameter for this level. Thus, we
13639 require structural equality checking to compare
13640 TEMPLATE_TEMPLATE_PARMs. */
13644 else
13648 {
13650 /* We might need to substitute into the types of non-type
13651 template parameters. */
13663 }
13664 }
13673 }
13676 }
13679 {
13687 {
13691 }
13694 {
13698 }
13701 {
13705 }
13711 }
13714 /* We should never be tsubsting a binfo. */
13718 /* A vector of template arguments. */
13724 {
13728 /* [temp.deduct]
13730 Type deduction may fail for any of the following
13731 reasons:
13733 -- Attempting to create a pointer to reference type.
13734 -- Attempting to create a reference to a reference type or
13735 a reference to void.
13737 Core issue 106 says that creating a reference to a reference
13738 during instantiation is no longer a cause for failure. We
13739 only enforce this check in strict C++98 mode. */
13743 {
13746 /* We keep track of the last time we issued this error
13747 message to avoid spewing a ton of messages during a
13748 single bad template instantiation. */
13751 {
13756 else
13759 }
13762 }
13766 {
13768 {
13771 type);
13772 else
13774 type);
13775 }
13777 }
13779 {
13783 }
13785 /* In C++0x, during template argument substitution, when there is an
13786 attempt to create a reference to a reference type, reference
13787 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13789 "If a template-argument for a template-parameter T names a type
13790 that is a reference to a type A, an attempt to create the type
13791 'lvalue reference to cv T' creates the type 'lvalue reference to
13792 A,' while an attempt to create the type type rvalue reference to
13793 cv T' creates the type T"
13794 */
13795 r = cp_build_reference_type
13798 else
13803 /* Will this ever be needed for TYPE_..._TO values? */
13807 }
13809 {
13812 {
13813 /* [temp.deduct]
13815 Type deduction may fail for any of the following
13816 reasons:
13818 -- Attempting to create "pointer to member of T" when T
13819 is not a class type. */
13823 }
13825 {
13829 }
13831 {
13835 }
13838 {
13839 /* The type of the implicit object parameter gets its
13840 cv-qualifiers from the FUNCTION_TYPE. */
13841 tree memptr;
13842 tree method_type
13847 complain);
13848 }
13849 else
13852 complain);
13853 }
13856 {
13857 tree fntype;
13858 tree specs;
13863 /* Substitute the exception specification. */
13871 }
13873 {
13878 /* As an optimization, we avoid regenerating the array type if
13879 it will obviously be the same as T. */
13883 /* These checks should match the ones in create_array_type_for_decl.
13885 [temp.deduct]
13887 The deduction may fail for any of the following reasons:
13889 -- Attempting to create an array with an element type that
13890 is void, a function type, or a reference type, or [DR337]
13891 an abstract class type. */
13897 {
13901 }
13909 {
13912 }
13915 }
13918 {
13930 {
13934 }
13936 {
13937 /* Normally, make_typename_type does not require that the CTX
13938 have complete type in order to allow things like:
13940 template <class T> struct S { typename S<T>::X Y; };
13942 But, such constructs have already been resolved by this
13943 point, so here CTX really should have complete type, unless
13944 it's a partial instantiation. */
13947 {
13951 }
13952 }
13959 {
13962 }
13965 {
13967 {
13971 else
13973 }
13975 {
13979 else
13981 }
13982 }
13984 return cp_build_qualified_type_real
13986 }
13989 {
14001 }
14004 {
14005 tree type;
14021 complain);
14022 }
14025 {
14026 tree type;
14037 {
14039 {
14043 }
14046 }
14057 else
14058 {
14062 /* In a template ~id could be either a complement expression
14063 or an unqualified-id naming a destructor; if instantiating
14064 it produces an expression, it's not an id-expression or
14065 member access. */
14068 }
14073 }
14076 {
14080 }
14084 {
14085 tree r;
14088 {
14090 /* Set the already-substituted type. */
14092 }
14093 else
14101 }
14116 /* We should use one of the expression tsubsts for these codes. */
14122 }
14123 }
14125 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
14126 type of the expression on the left-hand side of the "." or "->"
14127 operator. */
14129 static tree
14132 {
14133 tree name;
14134 tree qualifying_scope;
14135 tree fns;
14136 tree optype;
14141 /* A baselink indicates a function from a base class. Both the
14142 BASELINK_ACCESS_BINFO and the base class referenced may
14143 indicate bases of the template class, rather than the
14144 instantiated class. In addition, lookups that were not
14145 ambiguous before may be ambiguous now. Therefore, we perform
14146 the lookup again. */
14153 {
14160 }
14166 {
14168 {
14172 }
14174 }
14176 /* If lookup found a single function, mark it as used at this
14177 point. (If it lookup found multiple functions the one selected
14178 later by overload resolution will be marked as used at that
14179 point.) */
14186 /* Add back the template arguments, if present. */
14190 unknown_type_node,
14192 template_args);
14193 /* Update the conversion operator type. */
14201 {
14203 qualifying_scope,
14204 object_type);
14206 /* We need to call adjust_result_of_qualified_name_lookup in case the
14207 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14208 so that we still get virtual function binding. */
14210 }
14212 }
14214 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14215 true if the qualified-id will be a postfix-expression in-and-of
14216 itself; false if more of the postfix-expression follows the
14217 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14218 of "&". */
14220 static tree
14224 {
14225 tree expr;
14226 tree scope;
14227 tree name;
14229 tree template_args;
14234 /* Figure out what name to look up. */
14237 {
14247 }
14248 else
14249 {
14252 }
14254 /* Substitute into the qualifying scope. When there are no ARGS, we
14255 are just trying to simplify a non-dependent expression. In that
14256 case the qualifying scope may be dependent, and, in any case,
14257 substituting will not help. */
14260 {
14263 }
14264 else
14268 {
14275 }
14278 {
14280 {
14281 /* A BIT_NOT_EXPR is used to represent a destructor. */
14283 {
14287 }
14288 else
14291 }
14292 else
14296 {
14298 {
14302 }
14304 }
14305 }
14308 {
14310 scope);
14311 /* Remember that there was a reference to this entity. */
14314 }
14317 {
14323 }
14326 {
14329 complain);
14330 else
14332 }
14338 {
14339 expr = (adjust_result_of_qualified_name_lookup
14341 expr = (finish_qualified_id_expr
14345 }
14347 /* Expressions do not generally have reference type. */
14349 /* However, if we're about to form a pointer-to-member, we just
14350 want the referenced member referenced. */
14358 }
14360 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14361 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14362 for tsubst. */
14364 static tree
14367 {
14374 {
14375 /* If we had an initializer but it
14376 instantiated to nothing,
14377 value-initialize the object. This will
14378 only occur when the initializer was a
14379 pack expansion where the parameter packs
14380 used in that expansion were of length
14381 zero. */
14383 complain);
14386 }
14389 }
14391 /* Like tsubst, but deals with expressions. This function just replaces
14392 template parms; to finish processing the resultant expression, use
14393 tsubst_copy_and_build or tsubst_expr. */
14395 static tree
14397 {
14399 tree r;
14407 {
14412 {
14413 /* We get here for a use of 'this' in an NSDMI as part of a
14414 constructor call or as part of an aggregate initialization. */
14416 && ((current_function_decl
14418 || (current_class_ref
14422 /* This can happen for a parameter name used later in a function
14423 declaration (such as in a late-specified return type). Just
14424 make a dummy decl, since it's only used for its type. */
14427 /* Give it the template pattern as its context; its true context
14428 hasn't been instantiated yet and this is good enough for
14429 mangling. */
14431 }
14440 {
14441 tree enum_type;
14442 tree v;
14446 /* There is no need to substitute into namespace-scope
14447 enumerators. */
14450 /* If ARGS is NULL, then T is known to be non-dependent. */
14454 /* Unfortunately, we cannot just call lookup_name here.
14455 Consider:
14457 template <int I> int f() {
14458 enum E { a = I };
14459 struct S { void g() { E e = a; } };
14460 };
14462 When we instantiate f<7>::S::g(), say, lookup_name is not
14463 clever enough to find f<7>::a. */
14464 enum_type
14474 /* We didn't find the name. That should never happen; if
14475 name-lookup found it during preliminary parsing, we
14476 should find it again here during instantiation. */
14478 }
14483 {
14484 /* Check for a local specialization set up by
14485 tsubst_pack_expansion. */
14487 {
14491 }
14493 /* When retrieving a capture pack from a generic lambda, remove the
14494 lambda call op's own template argument list from ARGS. Only the
14495 template arguments active for the closure type should be used to
14496 retrieve the pack specialization. */
14502 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14503 tsubst_decl put in the hash table. */
14505 }
14508 {
14509 tree ctx;
14514 {
14517 {
14521 }
14523 }
14524 }
14534 {
14537 {
14538 /* First try name lookup to find the instantiation. */
14541 {
14542 /* Make sure that the one we found is the one we want. */
14548 }
14552 else
14553 {
14554 /* This can happen for a variable used in a
14555 late-specified return type of a local lambda, or for a
14556 local static or constant. Building a new VAR_DECL
14557 should be OK in all those cases. */
14560 {
14561 /* We can't call cp_finish_decl, so handle the
14562 initializer by hand. */
14573 }
14580 }
14581 /* Remember this for subsequent uses. */
14584 }
14585 }
14586 else
14596 /* An OVERLOAD will always be a non-dependent overload set; an
14597 overload set from function scope will just be represented with an
14598 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14614 {
14615 /* Template template argument like the following example need
14616 special treatment:
14618 template <template <class> class TT> struct C {};
14619 template <class T> struct D {
14620 template <class U> struct E {};
14621 C<E> c; // #1
14622 };
14623 D<int> d; // #2
14625 We are processing the template argument `E' in #1 for
14626 the template instantiation #2. Originally, `E' is a
14627 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14628 have to substitute this with one having context `D<int>'. */
14632 }
14633 else
14634 /* Ordinary template template argument. */
14645 {
14649 }
14654 {
14663 /* We only want to compute the number of arguments. */
14666 else
14673 {
14675 /* Set TREE_USED for the benefit of -Wunused. */
14679 }
14687 {
14692 else
14698 else
14701 }
14702 else
14704 }
14706 {
14714 }
14715 /* Fall through */
14731 {
14735 }
14738 {
14739 tree object;
14740 tree name;
14745 {
14749 }
14752 {
14762 }
14767 in_decl);
14768 else
14771 }
14809 {
14813 }
14816 {
14821 }
14824 {
14828 }
14831 {
14839 }
14845 {
14852 }
14855 {
14862 }
14865 {
14872 }
14875 {
14876 /* Substituted template arguments */
14885 }
14888 {
14908 }
14933 /* Fall through. */
14936 {
14939 }
14940 else
14944 /* This is handled by tsubst_copy_and_build. */
14948 {
14952 }
14955 /* We shouldn't have built any of these during initial template
14956 generation. Instead, they should be built during instantiation
14957 in response to the saved STMT_IS_FULL_EXPR_P setting. */
14961 {
14971 }
14989 {
14990 /* Instantiate any typedefs in the type. */
14995 }
14998 /* These can sometimes show up in a partial instantiation, but never
14999 involve template parms. */
15013 /* We shouldn't get here, but keep going if !flag_checking. */
15017 }
15018 }
15020 /* Helper function for tsubst_omp_clauses, used for instantiation of
15021 OMP_CLAUSE_DECL of clauses. */
15023 static tree
15025 tree in_decl)
15026 {
15030 /* Handle an OpenMP array section represented as a TREE_LIST (or
15031 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15032 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15033 TREE_LIST. We can handle it exactly the same as an array section
15034 (purpose, value, and a chain), even though the nomenclature
15035 (low_bound, length, etc) is different. */
15037 {
15038 tree low_bound
15044 in_decl);
15053 }
15056 /* Undo convert_from_reference tsubst_expr could have called. */
15062 }
15064 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15066 static tree
15069 {
15074 {
15080 {
15083 {
15089 }
15090 /* FALLTHRU */
15105 in_decl);
15137 {
15140 {
15147 }
15148 else
15150 }
15153 in_decl);
15159 in_decl);
15167 in_decl);
15169 {
15172 }
15177 else
15180 in_decl,
15204 }
15207 {
15217 /* tsubst_expr on SCOPE_REF results in returning
15218 finish_non_static_data_member result. Undo that here. */
15222 {
15227 {
15231 CASE_CONVERT:
15240 /* FALLTHRU */
15244 }
15245 }
15251 {
15254 {
15258 }
15259 }
15263 }
15264 }
15268 {
15273 {
15276 }
15277 }
15279 }
15281 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15283 static tree
15285 tree in_decl)
15286 {
15287 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15307 {
15310 else
15311 {
15315 }
15316 }
15321 #undef RECUR
15322 }
15324 /* Used to temporarily communicate the list of #pragma omp parallel
15325 clauses to #pragma omp for instantiation if they are combined
15326 together. */
15330 /* Substitute one OMP_FOR iterator. */
15332 static void
15337 {
15338 #define RECUR(NODE) \
15339 tsubst_expr ((NODE), args, complain, in_decl, \
15340 integral_constant_expression_p)
15347 {
15350 }
15356 {
15357 /* We need to jump through some hoops to handle declarations in the
15358 init-statement, since we might need to handle auto deduction,
15359 but we need to keep control of initialization. */
15363 }
15364 else
15365 {
15367 {
15370 {
15374 {
15378 CASE_CONVERT:
15386 {
15389 }
15390 /* FALLTHRU */
15394 }
15395 }
15396 }
15397 else
15399 }
15410 {
15412 {
15413 /* Declare the variable, but don't let that initialize it. */
15418 }
15423 {
15428 }
15429 else
15436 }
15439 {
15440 /* Declare and initialize the variable. */
15443 }
15445 {
15449 {
15451 {
15457 {
15460 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15465 }
15468 {
15470 decl);
15472 }
15475 {
15477 decl);
15479 }
15480 else
15482 }
15485 }
15487 {
15492 {
15495 }
15496 }
15497 }
15500 {
15504 }
15505 else
15509 {
15520 {
15528 }
15529 else
15535 {
15541 }
15545 {
15553 }
15554 else
15560 }
15566 #undef RECUR
15567 }
15569 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15570 of OMP_TARGET's body. */
15572 static tree
15574 {
15577 {
15586 }
15588 }
15590 /* Helper function for tsubst_expr. For decomposition declaration
15591 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15592 also the corresponding decls representing the identifiers
15593 of the decomposition declaration. Return DECL if successful
15594 or error_mark_node otherwise, set *FIRST to the first decl
15595 in the list chained through DECL_CHAIN and *CNT to the number
15596 of such decls. */
15598 static tree
15602 {
15607 decl2
15612 {
15628 {
15631 }
15632 else
15634 }
15637 }
15639 /* Like tsubst_copy for expressions, etc. but also does semantic
15640 processing. */
15642 tree
15645 {
15646 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15647 #define RECUR(NODE) \
15648 tsubst_expr ((NODE), args, complain, in_decl, \
15649 integral_constant_expression_p)
15652 tree r;
15653 location_t loc;
15665 {
15667 {
15668 tree_stmt_iterator i;
15672 }
15687 else
15696 {
15698 tree init;
15704 {
15714 else
15716 }
15718 {
15719 /* Don't build up decls for a variadic capture proxy, we'll
15720 instantiate the elements directly as needed. */
15722 }
15723 else
15724 {
15728 {
15729 /* By marking the declaration as instantiated, we avoid
15730 trying to instantiate it. Since instantiate_decl can't
15731 handle local variables, and since we've already done
15732 all that needs to be done, that's the right thing to
15733 do. */
15738 /* Anonymous aggregates are a special case. */
15741 {
15744 {
15748 }
15750 }
15756 {
15761 }
15762 else
15763 {
15768 {
15769 /* For __PRETTY_FUNCTION__ we have to adjust the
15770 initializer. */
15774 }
15775 else
15779 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15785 {
15787 tree first;
15793 }
15794 }
15795 }
15796 }
15799 }
15814 {
15822 {
15824 tree first;
15829 }
15830 else
15835 }
15861 else
15862 {
15869 }
15875 {
15884 }
15892 else
15900 else
15921 {
15928 }
15932 {
15934 tree label;
15941 }
15947 /* Computed goto's must be tsubst'd into. On the other hand,
15948 non-computed gotos must not be; the identifier in question
15949 will have no binding. */
15951 else
15957 {
15973 }
15978 {
15983 }
15984 else
15985 {
15990 else
15997 else
16003 else
16005 }
16009 {
16013 {
16015 /* Prevent instantiate_decl from trying to instantiate
16016 this variable. We've already done all that needs to be
16017 done. */
16020 }
16025 }
16031 {
16032 /* Local classes are not independent templates; they are
16033 instantiated along with their containing function. And this
16034 way we don't have to deal with pushing out of one local class
16035 to instantiate a member of another local class. */
16036 tree fn;
16037 /* Closures are handled by the LAMBDA_EXPR. */
16044 }
16048 {
16049 tree condition;
16052 condition =
16054 args,
16063 }
16069 in_decl);
16106 {
16121 in_decl);
16123 {
16130 }
16142 integral_constant_expression_p);
16153 else
16154 {
16162 }
16166 }
16171 /* FALLTHRU */
16178 in_decl);
16195 in_decl);
16206 {
16209 {
16210 /* For combined target teams, ensure the num_teams and
16211 thread_limit clause expressions are evaluated on the host,
16212 before entering the target construct. */
16213 tree c;
16219 {
16228 OMP_CLAUSE_FIRSTPRIVATE);
16232 }
16233 }
16234 }
16294 {
16299 {
16302 }
16308 }
16309 else
16310 {
16317 {
16320 }
16323 {
16328 {
16331 }
16337 }
16338 else
16339 {
16343 }
16346 }
16350 {
16356 {
16360 {
16365 }
16369 }
16370 else
16371 {
16376 }
16377 }
16381 {
16385 }
16405 /* If the first operand was a statement, we're done with it. */
16409 complain));
16421 integral_constant_expression_p));
16422 }
16425 out:
16428 #undef RECUR
16429 #undef RETURN
16430 }
16432 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16433 function. For description of the body see comment above
16434 cp_parser_omp_declare_reduction_exprs. */
16436 static void
16438 {
16444 tree_stmt_iterator tsi;
16455 {
16474 }
16476 {
16496 }
16497 }
16499 /* T is a postfix-expression that is not being used in a function
16500 call. Return the substituted version of T. */
16502 static tree
16504 tsubst_flags_t complain,
16505 tree in_decl)
16506 {
16510 else
16516 }
16518 /* Like tsubst but deals with expressions and performs semantic
16519 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16521 tree
16523 tree args,
16524 tsubst_flags_t complain,
16525 tree in_decl,
16528 {
16529 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16530 #define RECUR(NODE) \
16531 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16533 integral_constant_expression_p)
16536 location_t loc;
16545 /* N3276 decltype magic only applies to calls at the top level or on the
16546 right side of a comma. */
16551 {
16554 /* Fall through. */
16556 {
16557 tree decl;
16558 cp_id_kind idk;
16563 {
16566 }
16568 /* Look up the name. */
16571 /* By convention, expressions use ERROR_MARK_NODE to indicate
16572 failure, not NULL_TREE. */
16578 integral_constant_expression_p,
16586 input_location);
16590 {
16594 }
16596 }
16599 {
16600 tree object;
16613 {
16616 }
16617 else
16624 else
16626 }
16629 {
16633 {
16634 /* A type conversion to reference type will be enclosed in
16635 such an indirect ref, but the substitution of the cast
16636 will have also added such an indirect ref. */
16639 }
16640 else
16648 }
16651 {
16655 }
16658 {
16665 flags));
16666 }
16669 {
16673 }
16680 {
16681 tree type;
16687 {
16692 }
16698 {
16716 }
16719 }
16753 else
16755 in_decl);
16790 {
16797 tree r = build_x_binary_op
16799 op0,
16801 ? ERROR_MARK
16803 op1,
16805 ? ERROR_MARK
16813 }
16816 {
16820 }
16833 {
16842 }
16847 /* Fall through */
16850 {
16851 tree r;
16857 {
16858 /* When there are no ARGS, we are trying to evaluate a
16859 non-dependent expression from the parser. Trying to do
16860 the substitutions may not work. */
16863 }
16864 else
16865 {
16870 else
16873 /*integral_constant_expression_p=*/
16877 }
16881 else
16885 {
16887 {
16889 {
16893 }
16894 else
16898 }
16900 }
16902 }
16905 {
16915 }
16931 {
16935 tree r = build_x_modify_expr
16938 /* TREE_NO_WARNING must be set if either the expression was
16939 parenthesized or it uses an operator such as >>= rather
16940 than plain assignment. In the former case, it was already
16941 set and must be copied. In the latter case,
16942 build_x_modify_expr sets it and it must not be reset
16943 here. */
16948 }
16953 /* Remember that there was a reference to this entity. */
16960 {
16965 tree ret;
16969 else
16970 {
16974 }
16976 /* If there was an initializer in the original tree, but it
16977 instantiated to an empty list, then we should pass a
16978 non-NULL empty vector to tell build_new that it was an
16979 empty initializer() rather than no initializer. This can
16980 only happen when the initializer is a pack expansion whose
16981 parameter packs are of length zero. */
16984 else
16985 {
16989 else
16990 {
16993 }
16994 }
17000 complain);
17008 }
17011 {
17017 complain));
17018 }
17021 {
17025 integral_constant_expression_p);
17027 op0,
17030 }
17033 {
17034 tree function;
17039 tree ret;
17042 /* Internal function with no arguments. */
17046 /* When we parsed the expression, we determined whether or
17047 not Koenig lookup should be performed. */
17050 {
17053 }
17055 {
17060 }
17062 {
17063 /* Do nothing; calling tsubst_copy_and_build on an identifier
17064 would incorrectly perform unqualified lookup again.
17066 Note that we can also have an IDENTIFIER_NODE if the earlier
17067 unqualified lookup found a member function; in that case
17068 koenig_p will be false and we do want to do the lookup
17069 again to find the instantiated member function.
17071 FIXME but doing that causes c++/15272, so we need to stop
17072 using IDENTIFIER_NODE in that situation. */
17074 }
17075 else
17076 {
17078 {
17084 }
17085 else
17090 /* Avoid error about taking the address of a constructor. */
17094 in_decl,
17096 integral_constant_expression_p);
17100 }
17105 {
17110 else
17111 {
17112 /* Expand the pack expansion and push each entry onto
17113 CALL_ARGS. */
17116 {
17121 {
17126 }
17127 }
17128 else
17129 {
17130 /* A partial substitution. Add one entry. */
17132 }
17133 }
17134 }
17136 /* We do not perform argument-dependent lookup if normal
17137 lookup finds a non-function, in accordance with the
17138 expected resolution of DR 218. */
17141 /* If lookup found a member function, the Koenig lookup is
17142 not appropriate, even if an unqualified-name was used
17143 to denote the function. */
17146 /* Only do this when substitution turns a dependent call
17147 into a non-dependent call. */
17155 {
17157 {
17158 /* For backwards compatibility and good diagnostics, try
17159 the unqualified lookup again if we aren't in SFINAE
17160 context. */
17161 tree unq = (tsubst_copy_and_build
17163 integral_constant_expression_p));
17165 {
17168 }
17171 {
17172 /* In a lambda fn, we have to be careful to not
17173 introduce new this captures. Legacy code can't
17174 be using lambdas anyway, so it's ok to be
17175 stricter. */
17179 "and no declarations were found by "
17180 "argument-dependent lookup at the point "
17187 else
17191 {
17203 {
17205 input_location);
17207 "declarations in dependent base %qT are "
17213 else
17217 }
17218 else
17220 "%qD declared here, later in the "
17223 {
17226 }
17227 }
17230 }
17231 }
17233 {
17238 }
17239 }
17241 /* Remember that there was a reference to this entity. */
17245 {
17248 }
17250 /* Put back tf_decltype for the actual call. */
17255 {
17259 {
17261 "wrong number of arguments to "
17264 }
17265 else
17267 input_location),
17272 /* Unsupported internal function with arguments. */
17274 }
17277 complain);
17279 {
17294 complain);
17295 else
17296 ret = (build_new_method_call
17301 complain));
17302 }
17303 else
17306 koenig_p,
17307 complain);
17312 {
17318 {
17324 {
17326 /* The thunk location is not interesting. */
17328 }
17329 }
17330 }
17333 }
17336 {
17342 {
17344 {
17349 }
17350 else
17351 {
17356 }
17358 }
17359 else
17360 {
17363 }
17367 }
17370 {
17375 input_location));
17376 }
17379 {
17387 {
17388 /* We have pack expansions, so expand those and
17389 create a new list out of it. */
17392 tree chain;
17395 /* Expand the argument expressions. */
17403 /* Build the rest of the list. */
17408 /* Determine the number of arguments. */
17410 {
17413 }
17416 else
17417 {
17418 /* Since we only performed a partial substitution into
17419 the argument pack, we only RETURN (a single list
17420 node. */
17427 }
17429 /* Convert the argument vectors into a TREE_LIST */
17432 {
17433 /* Grab the Ith values. */
17434 i--;
17437 value
17441 /* Build the list (backwards). */
17443 }
17446 }
17462 }
17465 {
17466 tree object;
17467 tree object_type;
17468 tree member;
17469 tree r;
17473 /* Remember that there was a reference to this entity. */
17484 else
17490 {
17495 }
17499 {
17501 {
17506 {
17509 }
17511 {
17516 }
17517 }
17518 }
17521 {
17522 /* Lookup the template functions now that we know what the
17523 scope is. */
17531 {
17534 args);
17535 member = (adjust_result_of_qualified_name_lookup
17537 object_type));
17538 }
17539 else
17540 {
17542 input_location);
17544 }
17545 }
17549 {
17551 {
17555 else
17558 }
17560 }
17564 complain);
17568 }
17575 {
17583 tree r;
17588 /* digest_init will do the wrong thing if we let it. */
17592 /* We do not want to process the index of aggregate
17593 initializers as they are identifier nodes which will be
17594 looked up by digest_init. */
17600 {
17602 /* An identifier index is looked up in the type
17603 being initialized, not the current scope. */
17608 {
17609 /* Substitute into the pack expansion. */
17611 in_decl);
17615 ;
17617 /* Just move the argument into place. */
17619 else
17620 {
17621 /* Update the length of the final CONSTRUCTOR
17622 arguments vector, and note that we will need to
17623 copy.*/
17626 }
17627 }
17628 else
17630 }
17633 {
17638 {
17640 {
17645 }
17646 else
17648 }
17649 }
17659 }
17662 {
17665 {
17668 }
17669 else
17670 {
17673 }
17674 }
17680 {
17681 /* We don't build decls for an instantiation of a
17682 variadic capture proxy, we instantiate the elements
17683 when needed. */
17686 }
17687 /* Fall through */
17690 {
17692 /* ??? We're doing a subset of finish_id_expression here. */
17694 && !processing_template_decl
17695 && !cp_unevaluated_operand
17698 {
17700 /* Replace an evaluated use of the thread_local variable with
17701 a call to its wrapper. */
17703 }
17705 {
17709 }
17712 /* If the original type was a reference, we'll be wrapped in
17713 the appropriate INDIRECT_REF. */
17716 }
17719 {
17723 }
17726 {
17727 tree object_ptr
17734 }
17741 {
17752 }
17755 {
17761 integral_constant_expression_p);
17765 /* If the resulting list of expression statement is empty,
17766 fold it further into void_node. */
17771 }
17774 {
17792 /* For a function or variable scope, we want to use tsubst so that we
17793 don't complain about referring to an auto before deduction. */
17796 {
17797 /* Look up the parameter we want directly, as tsubst_copy
17798 doesn't do what we need. */
17804 /* FIXME Work around the parm not having DECL_CONTEXT set. */
17807 }
17809 /* For a field, use tsubst_copy so that we look up the existing field
17810 rather than build a new one. */
17812 else
17819 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17821 /* Now that we know visibility, instantiate the type so we have a
17822 declaration of the op() for later calls to lambda_function. */
17833 }
17836 /* We can get here for a constant initializer of non-dependent type.
17837 FIXME stop folding in cp_parser_initializer_clause. */
17838 {
17840 complain);
17842 }
17846 integral_constant_expression_p));
17852 {
17857 complain));
17858 }
17864 /* Handle Objective-C++ constructs, if appropriate. */
17865 {
17866 tree subst
17871 }
17873 }
17875 #undef RECUR
17876 #undef RETURN
17877 out:
17880 }
17882 /* Verify that the instantiated ARGS are valid. For type arguments,
17883 make sure that the type's linkage is ok. For non-type arguments,
17884 make sure they are constants if they are integral or enumerations.
17885 Emit an error under control of COMPLAIN, and return TRUE on error. */
17887 static bool
17889 {
17893 {
17903 }
17905 {
17906 /* [basic.link]: A name with no linkage (notably, the name
17907 of a class or enumeration declared in a local scope)
17908 shall not be used to declare an entity with linkage.
17909 This implies that names with no linkage cannot be used as
17910 template arguments
17912 DR 757 relaxes this restriction for C++0x. */
17917 {
17918 /* DR 488 makes use of a type with no linkage cause
17919 type deduction to fail. */
17921 {
17924 else
17927 }
17929 }
17930 /* In order to avoid all sorts of complications, we do not
17931 allow variably-modified types as template arguments. */
17933 {
17937 }
17938 }
17939 /* Class template and alias template arguments should be OK. */
17941 ;
17942 /* A non-type argument of integral or enumerated type must be a
17943 constant. */
17948 {
17952 }
17954 }
17956 static bool
17958 {
17963 {
17966 }
17970 }
17972 /* We're out of SFINAE context now, so generate diagnostics for the access
17973 errors we saw earlier when instantiating D from TMPL and ARGS. */
17975 static void
17977 {
17989 }
17991 /* Instantiate the indicated variable, function, or alias template TMPL with
17992 the template arguments in TARG_PTR. */
17994 static tree
17996 {
17998 tree fndecl;
17999 tree gen_tmpl;
18000 tree spec;
18008 /* If this function is a clone, handle it specially. */
18010 {
18011 tree spec;
18012 tree clone;
18014 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18015 DECL_CLONED_FUNCTION. */
18021 /* Look for the clone. */
18025 /* We should always have found the clone by now. */
18028 }
18033 /* Check to see if we already have this specialization. */
18037 /* targ_ptr only has the innermost template args, so add the outer ones
18038 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18039 the case of a non-dependent call within a template definition). */
18040 targ_ptr = (add_outermost_template_args
18042 targ_ptr));
18044 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18045 but it doesn't seem to be on the hot path. */
18054 {
18056 {
18060 }
18062 }
18065 complain))
18068 /* We are building a FUNCTION_DECL, during which the access of its
18069 parameters and return types have to be checked. However this
18070 FUNCTION_DECL which is the desired context for access checking
18071 is not built yet. We solve this chicken-and-egg problem by
18072 deferring all checks until we have the FUNCTION_DECL. */
18075 /* Instantiation of the function happens in the context of the function
18076 template, not the context of the overload resolution we're doing. */
18078 /* If there are dependent arguments, e.g. because we're doing partial
18079 ordering, make sure processing_template_decl stays set. */
18083 {
18087 }
18093 {
18094 /* We need to determine if we're using a partial or explicit
18095 specialization now, because the type of the variable could be
18096 different. */
18102 {
18107 }
18108 }
18110 /* Substitute template parameters to obtain the specialization. */
18118 {
18121 }
18123 /* The DECL_TI_TEMPLATE should always be the immediate parent
18124 template, not the most general template. */
18128 /* Now we know the specialization, compute access previously
18129 deferred. Do no access control for inheriting constructors,
18130 as we already checked access for the inherited constructor. */
18133 {
18138 }
18141 /* If we've just instantiated the main entry point for a function,
18142 instantiate all the alternate entry points as well. We do this
18143 by cloning the instantiation of the main entry point, not by
18144 instantiating the template clones. */
18149 {
18151 {
18152 /* Remember to reinstantiate when we're out of SFINAE so the user
18153 can see the errors. */
18155 }
18157 }
18159 }
18161 /* Wrapper for instantiate_template_1. */
18163 tree
18165 {
18166 tree ret;
18171 }
18173 /* Instantiate the alias template TMPL with ARGS. Also push a template
18174 instantiation level, which instantiate_template doesn't do because
18175 functions and variables have sufficient context established by the
18176 callers. */
18178 static tree
18180 {
18187 {
18190 }
18192 args =
18200 /* We can't free this if a pending_template entry or last_error_tinst_level
18201 is pointing at it. */
18207 }
18209 /* PARM is a template parameter pack for FN. Returns true iff
18210 PARM is used in a deducible way in the argument list of FN. */
18212 static bool
18214 {
18217 {
18219 tree packs;
18225 {
18226 /* The template parameter pack is used in a function parameter
18227 pack. If this is the end of the parameter list, the
18228 template parameter pack is deducible. */
18231 else
18232 /* Otherwise, not. Well, it could be deduced from
18233 a non-pack parameter, but doing so would end up with
18234 a deduction mismatch, so don't bother. */
18236 }
18237 }
18238 /* The template parameter pack isn't used in any function parameter
18239 packs, but it might be used deeper, e.g. tuple<Args...>. */
18241 }
18243 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18244 NARGS elements of the arguments that are being used when calling
18245 it. TARGS is a vector into which the deduced template arguments
18246 are placed.
18248 Returns either a FUNCTION_DECL for the matching specialization of FN or
18249 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18250 true, diagnostics will be printed to explain why it failed.
18252 If FN is a conversion operator, or we are trying to produce a specific
18253 specialization, RETURN_TYPE is the return type desired.
18255 The EXPLICIT_TARGS are explicit template arguments provided via a
18256 template-id.
18258 The parameter STRICT is one of:
18260 DEDUCE_CALL:
18261 We are deducing arguments for a function call, as in
18262 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18263 deducing arguments for a call to the result of a conversion
18264 function template, as in [over.call.object].
18266 DEDUCE_CONV:
18267 We are deducing arguments for a conversion function, as in
18268 [temp.deduct.conv].
18270 DEDUCE_EXACT:
18271 We are deducing arguments when doing an explicit instantiation
18272 as in [temp.explicit], when determining an explicit specialization
18273 as in [temp.expl.spec], or when taking the address of a function
18274 template, as in [temp.deduct.funcaddr]. */
18276 tree
18278 tree explicit_targs,
18279 tree targs,
18282 tree return_type,
18283 unification_kind_t strict,
18287 {
18288 tree parms;
18289 tree fntype;
18302 tree tinst;
18308 full_targs = (add_outermost_template_args
18310 targs));
18315 /* In C++0x, it's possible to have a function template whose type depends
18316 on itself recursively. This is most obvious with decltype, but can also
18317 occur with enumeration scope (c++/48969). So we need to catch infinite
18318 recursion and reject the substitution at deduction time; this function
18319 will return error_mark_node for any repeated substitution.
18321 This also catches excessive recursion such as when f<N> depends on
18322 f<N-1> across all integers, and returns error_mark_node for all the
18323 substitutions back up to the initial one.
18325 This is, of course, not reentrant. */
18335 {
18336 /* [temp.deduct]
18338 The specified template arguments must match the template
18339 parameters in kind (i.e., type, nontype, template), and there
18340 must not be more arguments than there are parameters;
18341 otherwise type deduction fails.
18343 Nontype arguments must match the types of the corresponding
18344 nontype template parameters, or must be convertible to the
18345 types of the corresponding nontype parameters as specified in
18346 _temp.arg.nontype_, otherwise type deduction fails.
18348 All references in the function type of the function template
18349 to the corresponding template parameters are replaced by the
18350 specified template argument values. If a substitution in a
18351 template parameter or in the function type of the function
18352 template results in an invalid type, type deduction fails. */
18363 explicit_targs);
18365 /* Adjust any explicit template arguments before entering the
18366 substitution context. */
18367 explicit_targs
18369 complain,
18375 /* Substitute the explicit args into the function type. This is
18376 necessary so that, for instance, explicitly declared function
18377 arguments can match null pointed constants. If we were given
18378 an incomplete set of explicit args, we must not do semantic
18379 processing during substitution as we could create partial
18380 instantiations. */
18382 {
18387 /* Dig out the actual parm. */
18390 {
18393 }
18395 {
18398 }
18401 /* No explicit argument for this template parameter. */
18405 {
18406 /* Mark the argument pack as "incomplete". We could
18407 still deduce more arguments during unification.
18408 We remove this mark in type_unification_real. */
18410 {
18414 }
18416 /* We have some incomplete argument packs. */
18418 }
18419 }
18423 {
18426 }
18429 /* Ignore any access checks; we'll see them again in
18430 instantiate_template and they might have the wrong
18431 access path at this point. */
18443 /* Place the explicitly specified arguments in TARGS. */
18447 }
18449 /* Never do unification on the 'this' parameter. */
18453 {
18454 /* We're deducing for a call to the result of a template conversion
18455 function. The parms we really want are in return_type. */
18459 }
18461 {
18470 }
18472 /* We allow incomplete unification without an error message here
18473 because the standard doesn't seem to explicitly prohibit it. Our
18474 callers must be ready to deal with unification failures in any
18475 event. */
18478 /* If we aren't explaining yet, push tinst context so we can see where
18479 any errors (e.g. from class instantiations triggered by instantiation
18480 of default template arguments) come from. If we are explaining, this
18481 context is redundant. */
18483 {
18486 }
18488 /* type_unification_real will pass back any access checks from default
18489 template argument substitution. */
18501 /* Now that we have bindings for all of the template arguments,
18502 ensure that the arguments deduced for the template template
18503 parameters have compatible template parameter lists. We cannot
18504 check this property before we have deduced all template
18505 arguments, because the template parameter types of a template
18506 template parameter might depend on prior template parameters
18507 deduced after the template template parameter. The following
18508 ill-formed example illustrates this issue:
18510 template<typename T, template<T> class C> void f(C<5>, T);
18512 template<int N> struct X {};
18514 void g() {
18515 f(X<5>(), 5l); // error: template argument deduction fails
18516 }
18518 The template parameter list of 'C' depends on the template type
18519 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18520 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18521 time that we deduce 'C'. */
18524 {
18527 }
18529 /* All is well so far. Now, check:
18531 [temp.deduct]
18533 When all template arguments have been deduced, all uses of
18534 template parameters in nondeduced contexts are replaced with
18535 the corresponding deduced argument values. If the
18536 substitution results in an invalid type, as described above,
18537 type deduction fails. */
18540 {
18543 }
18545 /* Also collect access checks from the instantiation. */
18558 /* Now perform any access checks encountered during substitution. */
18565 /* If we're looking for an exact match, check that what we got
18566 is indeed an exact match. It might not be if some template
18567 parameters are used in non-deduced contexts. But don't check
18568 for an exact match if we have dependent template arguments;
18569 in that case we're doing partial ordering, and we already know
18570 that we have two candidates that will provide the actual type. */
18572 {
18576 tree sarg
18582 {
18586 }
18587 }
18589 /* After doing deduction with the inherited constructor, actually return an
18590 instantiation of the inheriting constructor. */
18596 fail:
18599 {
18601 /* Reset once we're all the way out. */
18603 }
18605 /* We can't free this if a pending_template entry or last_error_tinst_level
18606 is pointing at it. */
18612 }
18614 /* Adjust types before performing type deduction, as described in
18615 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
18616 sections are symmetric. PARM is the type of a function parameter
18617 or the return type of the conversion function. ARG is the type of
18618 the argument passed to the call, or the type of the value
18619 initialized with the result of the conversion function.
18620 ARG_EXPR is the original argument expression, which may be null. */
18622 static int
18626 tree arg_expr)
18627 {
18631 {
18636 /* Swap PARM and ARG throughout the remainder of this
18637 function; the handling is precisely symmetric since PARM
18638 will initialize ARG rather than vice versa. */
18643 /* Core issue #873: Do the DR606 thing (see below) for these cases,
18644 too, but here handle it by stripping the reference from PARM
18645 rather than by adding it to ARG. */
18653 /* Nothing else to do in this case. */
18658 }
18661 {
18662 /* [temp.deduct.call]
18664 If P is not a reference type:
18666 --If A is an array type, the pointer type produced by the
18667 array-to-pointer standard conversion (_conv.array_) is
18668 used in place of A for type deduction; otherwise,
18670 --If A is a function type, the pointer type produced by
18671 the function-to-pointer standard conversion
18672 (_conv.func_) is used in place of A for type deduction;
18673 otherwise,
18675 --If A is a cv-qualified type, the top level
18676 cv-qualifiers of A's type are ignored for type
18677 deduction. */
18682 else
18684 }
18686 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
18687 reference to a cv-unqualified template parameter that does not represent a
18688 template parameter of a class template (during class template argument
18689 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
18690 an lvalue, the type "lvalue reference to A" is used in place of A for type
18691 deduction. */
18698 /* try_one_overload doesn't provide an arg_expr, but
18699 functions are always lvalues. */
18703 /* [temp.deduct.call]
18705 If P is a cv-qualified type, the top level cv-qualifiers
18706 of P's type are ignored for type deduction. If P is a
18707 reference type, the type referred to by P is used for
18708 type deduction. */
18711 {
18714 }
18716 /* DR 322. For conversion deduction, remove a reference type on parm
18717 too (which has been swapped into ARG). */
18722 }
18724 /* Subroutine of unify_one_argument. PARM is a function parameter of a
18725 template which does contain any deducible template parameters; check if
18726 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
18727 unify_one_argument. */
18729 static int
18732 {
18733 tree type;
18737 else
18744 {
18748 }
18750 {
18755 }
18759 else
18761 }
18765 /* Returns true iff the expression EXPR is one from which a template
18766 argument can be deduced. In other words, if it's an undecorated
18767 use of a template non-type parameter. */
18769 static bool
18771 {
18772 /* Strip implicit conversions. */
18776 }
18778 /* Returns true iff the array domain DOMAIN uses a template parameter in a
18779 deducible way; that is, if it has a max value of <PARM> - 1. */
18781 static bool
18783 {
18792 }
18794 /* Returns true iff the template arguments ARGS use a template parameter
18795 in a deducible way. */
18797 static bool
18799 {
18801 {
18806 else
18807 {
18814 else
18816 }
18819 }
18821 }
18823 /* Returns true iff TYPE contains any deducible references to template
18824 parameters, as per 14.8.2.5. */
18826 static bool
18828 {
18832 /* T
18833 cv-list T
18834 TT<T>
18835 TT<i>
18836 TT<> */
18841 /* T*
18842 T&
18843 T&& */
18847 /* T[integer-constant ]
18848 type [i] */
18853 /* T type ::*
18854 type T::*
18855 T T::*
18856 T (type ::*)()
18857 type (T::*)()
18858 type (type ::*)(T)
18859 type (T::*)(T)
18860 T (type ::*)(T)
18861 T (T::*)()
18862 T (T::*)(T) */
18865 || (uses_deducible_template_parms
18868 /* template-name <T> (where template-name refers to a class template)
18869 template-name <i> (where template-name refers to a class template) */
18876 /* type (T)
18877 T()
18878 T(T) */
18881 {
18890 }
18893 }
18895 /* Subroutine of type_unification_real and unify_pack_expansion to
18896 handle unification of a single P/A pair. Parameters are as
18897 for those functions. */
18899 static int
18903 {
18910 /* We can't deduce anything from this, but we might get all the
18911 template args from other function args. */
18914 /* Implicit conversions (Clause 4) will be performed on a function
18915 argument to convert it to the type of the corresponding function
18916 parameter if the parameter type contains no template-parameters that
18917 participate in template argument deduction. */
18920 /* For function parameters with no deducible template parameters,
18921 just return. We'll check non-dependent conversions later. */
18925 {
18927 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
18928 | UNIFY_ALLOW_MORE_CV_QUAL
18942 }
18944 /* We only do these transformations if this is the top-level
18945 parameter_type_list in a call or declaration matching; in other
18946 situations (nested function declarators, template argument lists) we
18947 won't be comparing a type to an expression, and we don't do any type
18948 adjustments. */
18950 {
18952 {
18955 {
18956 /* [temp.deduct.type] A template-argument can be
18957 deduced from a pointer to function or pointer
18958 to member function argument if the set of
18959 overloaded functions does not contain function
18960 templates and at most one of a set of
18961 overloaded functions provides a unique
18962 match. */
18969 }
18975 }
18977 arg_strict |=
18979 }
18980 else
18985 /* For deduction from an init-list we need the actual list. */
18989 }
18991 /* for_each_template_parm callback that always returns 0. */
18993 static int
18995 {
18997 }
18999 /* for_each_template_parm any_fn callback to handle deduction of a template
19000 type argument from the type of an array bound. */
19002 static int
19004 {
19012 {
19018 }
19020 /* Keep walking. */
19022 }
19024 /* Try to deduce any not-yet-deduced template type arguments from the type of
19025 an array bound. This is handled separately from unify because 14.8.2.5 says
19026 "The type of a type parameter is only deduced from an array bound if it is
19027 not otherwise deduced." */
19029 static void
19031 {
19036 }
19038 /* Most parms like fn_type_unification.
19040 If SUBR is 1, we're being called recursively (to unify the
19041 arguments of a function or method parameter of a function
19042 template).
19044 CHECKS is a pointer to a vector of access checks encountered while
19045 substituting default template arguments. */
19047 static int
19049 tree full_targs,
19050 tree xparms,
19054 unification_kind_t strict,
19058 {
19063 tree parms;
19074 /* Reset the number of non-defaulted template arguments contained
19075 in TARGS. */
19078 again:
19086 {
19091 /* For a function parameter pack that occurs at the end of the
19092 parameter-declaration-list, the type A of each remaining
19093 argument of the call is compared with the type P of the
19094 declarator-id of the function parameter pack. */
19100 /* For a function parameter pack that does not occur at the
19101 end of the parameter-declaration-list, the type of the
19102 parameter pack is a non-deduced context. */
19109 explain_p))
19111 }
19116 {
19117 /* Unify the remaining arguments with the pack expansion type. */
19118 tree argvec;
19121 /* Allocate a TREE_VEC and copy in all of the arguments */
19126 /* Copy the parameter into parmvec. */
19132 /* Advance to the end of the list of parameters. */
19134 }
19136 /* Fail if we've reached the end of the parm list, and more args
19137 are present, and the parm list isn't variadic. */
19140 /* Fail if parms are left and they don't have default values and
19141 they aren't all deduced as empty packs (c++/57397). This is
19142 consistent with sufficient_parms_p. */
19145 {
19149 do
19150 {
19153 count++;
19155 }
19159 type_pack_p);
19160 }
19163 {
19164 tsubst_flags_t complain = (explain_p
19165 ? tf_warning_or_error
19170 {
19174 /* Clear the "incomplete" flags on all argument packs now so that
19175 substituting them into later default arguments works. */
19177 {
19180 }
19188 {
19193 }
19195 /* If this is an undeduced nontype parameter that depends on
19196 a type parameter, try another pass; its type may have been
19197 deduced from a later argument than the one from which
19198 this parameter can be deduced. */
19202 {
19205 }
19207 /* Core issue #226 (C++0x) [temp.deduct]:
19209 If a template argument has not been deduced, its
19210 default template argument, if any, is used.
19212 When we are in C++98 mode, TREE_PURPOSE will either
19213 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19214 to explicitly check cxx_dialect here. */
19216 /* OK, there is a default argument. Wait until after the
19217 conversion check to do substitution. */
19220 /* If the type parameter is a parameter pack, then it will
19221 be deduced to an empty parameter pack. */
19223 {
19224 tree arg;
19227 {
19231 }
19232 else
19239 }
19242 }
19244 /* DR 1391: All parameters have args, now check non-dependent parms for
19245 convertibility. */
19249 {
19255 /* For a function parameter pack that occurs at the end of the
19256 parameter-declaration-list, the type A of each remaining
19257 argument of the call is compared with the type P of the
19258 declarator-id of the function parameter pack. */
19264 /* For a function parameter pack that does not occur at the
19265 end of the parameter-declaration-list, the type of the
19266 parameter pack is a non-deduced context. */
19275 explain_p))
19277 }
19279 /* Now substitute into the default template arguments. */
19281 {
19305 else
19313 {
19315 /* The position of the first default template argument,
19316 is also the number of non-defaulted arguments in TARGS.
19317 Record that. */
19320 }
19321 }
19325 }
19331 }
19333 /* Subroutine of type_unification_real. Args are like the variables
19334 at the call site. ARG is an overloaded function (or template-id);
19335 we try deducing template args from each of the overloads, and if
19336 only one succeeds, we go with that. Modifies TARGS and returns
19337 true on success. */
19339 static bool
19341 tree targs,
19342 tree parm,
19343 tree arg,
19344 unification_kind_t strict,
19347 {
19354 {
19357 }
19358 else
19362 /* Handle `&x' where `x' is some static or non-static member
19363 function name. */
19369 /* Strip baselink information. */
19374 {
19375 /* If we got some explicit template args, we need to plug them into
19376 the affected templates before we try to unify, in case the
19377 explicit args will completely resolve the templates in question. */
19384 {
19397 {
19402 {
19405 }
19406 }
19409 }
19410 /* If no templates (or more than one) are fully resolved by the
19411 explicit arguments, this template-id is a non-deduced context; it
19412 could still be OK if we deduce all template arguments for the
19413 enclosing call through other arguments. */
19416 }
19419 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19420 -- but the deduction does not succeed because the expression is
19421 not just the function on its own. */
19423 else
19429 {
19432 }
19434 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19435 to function or pointer to member function argument if the set of
19436 overloaded functions does not contain function templates and at most
19437 one of a set of overloaded functions provides a unique match.
19439 So if we found multiple possibilities, we return success but don't
19440 deduce anything. */
19443 {
19447 {
19452 /* Don't forget explicit template arguments in a pack. */
19456 }
19457 }
19462 }
19464 /* Core DR 115: In contexts where deduction is done and fails, or in
19465 contexts where deduction is not done, if a template argument list is
19466 specified and it, along with any default template arguments, identifies
19467 a single function template specialization, then the template-id is an
19468 lvalue for the function template specialization. */
19470 tree
19472 {
19485 {
19488 }
19490 {
19493 }
19495 {
19498 }
19501 {
19505 /* If we got some explicit template args, we need to plug them into
19506 the affected templates before we try to unify, in case the
19507 explicit args will completely resolve the templates in question. */
19515 {
19528 {
19531 {
19534 }
19536 {
19539 }
19540 }
19541 }
19543 {
19551 {
19552 tree base
19555 }
19559 }
19561 /* There were no good options and at least one bad one, so let the
19562 user know what the problem is. */
19564 }
19566 }
19568 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19569 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19570 different overloads deduce different arguments for a given parm.
19571 ADDR_P is true if the expression for which deduction is being
19572 performed was of the form "& fn" rather than simply "fn".
19574 Returns 1 on success. */
19576 static int
19578 tree orig_targs,
19579 tree targs,
19580 tree parm,
19581 tree arg,
19582 unification_kind_t strict,
19586 {
19588 tree tempargs;
19594 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19595 to function or pointer to member function argument if the set of
19596 overloaded functions does not contain function templates and at most
19597 one of a set of overloaded functions provides a unique match.
19599 So if this is a template, just return success. */
19611 /* We don't copy orig_targs for this because if we have already deduced
19612 some template args from previous args, unify would complain when we
19613 try to deduce a template parameter for the same argument, even though
19614 there isn't really a conflict. */
19621 /* First make sure we didn't deduce anything that conflicts with
19622 explicitly specified args. */
19624 {
19631 /* Since we're unifying against ourselves, we will fill in
19632 template args used in the function parm list with our own
19633 template parms. Discard them. */
19636 {
19637 /* Check that the argument at each index of the deduced argument pack
19638 is equivalent to the corresponding explicitly specified argument.
19639 We may have deduced more arguments than were explicitly specified,
19640 and that's OK. */
19656 }
19659 }
19662 {
19667 }
19670 }
19672 /* PARM is a template class (perhaps with unbound template
19673 parameters). ARG is a fully instantiated type. If ARG can be
19674 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
19675 TARGS are as for unify. */
19677 static tree
19680 {
19681 tree copy_of_targs;
19691 /* We need to make a new template argument vector for the call to
19692 unify. If we used TARGS, we'd clutter it up with the result of
19693 the attempted unification, even if this class didn't work out.
19694 We also don't want to commit ourselves to all the unifications
19695 we've already done, since unification is supposed to be done on
19696 an argument-by-argument basis. In other words, consider the
19697 following pathological case:
19699 template <int I, int J, int K>
19700 struct S {};
19702 template <int I, int J>
19703 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
19705 template <int I, int J, int K>
19706 void f(S<I, J, K>, S<I, I, I>);
19708 void g() {
19709 S<0, 0, 0> s0;
19710 S<0, 1, 2> s2;
19712 f(s0, s2);
19713 }
19715 Now, by the time we consider the unification involving `s2', we
19716 already know that we must have `f<0, 0, 0>'. But, even though
19717 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
19718 because there are two ways to unify base classes of S<0, 1, 2>
19719 with S<I, I, I>. If we kept the already deduced knowledge, we
19720 would reject the possibility I=1. */
19724 {
19728 }
19730 /* If unification failed, we're done. */
19736 }
19738 /* Given a template type PARM and a class type ARG, find the unique
19739 base type in ARG that is an instance of PARM. We do not examine
19740 ARG itself; only its base-classes. If there is not exactly one
19741 appropriate base class, return NULL_TREE. PARM may be the type of
19742 a partial specialization, as well as a plain template type. Used
19743 by unify. */
19745 static enum template_base_result
19748 {
19750 tree binfo;
19756 {
19757 /* The type could not be completed. */
19760 }
19762 /* Walk in inheritance graph order. The search order is not
19763 important, and this avoids multiple walks of virtual bases. */
19765 {
19770 {
19771 /* If there is more than one satisfactory baseclass, then:
19773 [temp.deduct.call]
19775 If they yield more than one possible deduced A, the type
19776 deduction fails.
19778 applies. */
19780 {
19783 }
19786 }
19787 }
19791 }
19793 /* Returns the level of DECL, which declares a template parameter. */
19795 static int
19797 {
19799 {
19809 }
19811 }
19813 /* Decide whether ARG can be unified with PARM, considering only the
19814 cv-qualifiers of each type, given STRICT as documented for unify.
19815 Returns nonzero iff the unification is OK on that basis. */
19817 static int
19819 {
19825 {
19826 /* Although a CVR qualifier is ignored when being applied to a
19827 substituted template parameter ([8.3.2]/1 for example), that
19828 does not allow us to unify "const T" with "int&" because both
19829 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
19830 It is ok when we're allowing additional CV qualifiers
19831 at the outer level [14.8.2.1]/3,1st bullet. */
19841 }
19852 }
19854 /* Determines the LEVEL and INDEX for the template parameter PARM. */
19855 void
19857 {
19861 {
19864 }
19865 else
19866 {
19869 }
19870 }
19872 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
19873 do { \
19874 if (unify (TP, TA, P, A, S, EP)) \
19875 return 1; \
19876 } while (0)
19878 /* Unifies the remaining arguments in PACKED_ARGS with the pack
19879 expansion at the end of PACKED_PARMS. Returns 0 if the type
19880 deduction succeeds, 1 otherwise. STRICT is the same as in
19881 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
19882 function call argument list. We'll need to adjust the arguments to make them
19883 types. SUBR tells us if this is from a recursive call to
19884 type_unification_real, or for comparing two template argument
19885 lists. */
19887 static int
19891 {
19892 tree parm
19902 /* Determine the parameter packs we will be deducing from the
19903 pattern, and record their current deductions. */
19906 {
19910 /* Determine the index and level of this parameter pack. */
19913 /* Keep track of the parameter packs and their corresponding
19914 argument packs. */
19917 }
19919 /* Loop through all of the arguments that have not yet been
19920 unified and unify each with the pattern. */
19922 {
19923 tree parm;
19927 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
19928 or the element of its argument pack at the current index if
19929 this argument was explicitly specified. */
19931 {
19940 {
19943 }
19945 }
19947 /* If we had explicit template arguments, substitute them into the
19948 pattern before deduction. */
19950 {
19951 /* Some arguments might still be unspecified or dependent. */
19959 NULL_TREE);
19964 }
19965 else
19968 /* Unify the pattern with the current argument. */
19970 explain_p))
19973 /* For each parameter pack, collect the deduced value. */
19975 {
19981 }
19982 }
19984 /* Verify that the results of unification with the parameter packs
19985 produce results consistent with what we've seen before, and make
19986 the deduced argument packs available. */
19988 {
19995 /* By default keep the original deduced argument pack.
19996 If necessary, more specific code is going to update the
19997 resulting deduced argument later down in this function. */
20001 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20002 actually deduce anything. */
20010 {
20011 /* If we had fewer function args than explicit template args,
20012 just use the explicits. */
20017 }
20020 {
20021 tree result;
20022 /* Build the deduced *_ARGUMENT_PACK. */
20024 {
20029 }
20030 else
20035 /* Note the deduced argument packs for this parameter
20036 pack. */
20038 }
20042 {
20043 /* We only had the explicitly-provided arguments before, but
20044 now we have a complete set of arguments. */
20050 }
20051 else
20052 {
20058 /* Inconsistent unification of this parameter pack. */
20060 bad_old_arg,
20061 bad_new_arg);
20062 }
20063 }
20066 }
20068 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20069 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20070 parameters and return value are as for unify. */
20072 static int
20076 {
20077 tree parm_max;
20078 tree arg_max;
20082 /* Our representation of array types uses "N - 1" as the
20083 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20084 not an integer constant. We cannot unify arbitrarily
20085 complex expressions, so we eliminate the MINUS_EXPRs
20086 here. */
20090 {
20093 }
20097 {
20098 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20099 trying to unify the type of a variable with the type
20100 of a template parameter. For example:
20102 template <unsigned int N>
20103 void f (char (&) [N]);
20104 int g();
20105 void h(int i) {
20106 char a[g(i)];
20107 f(a);
20108 }
20110 Here, the type of the ARG will be "int [g(i)]", and
20111 may be a SAVE_EXPR, etc. */
20115 }
20117 /* If only one of the bounds used a MINUS_EXPR, compensate
20118 by adding one to the other bound. */
20121 integer_type_node,
20122 parm_max,
20123 integer_one_node);
20126 integer_type_node,
20127 arg_max,
20128 integer_one_node);
20132 }
20134 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20138 static pa_kind_t
20140 {
20149 else
20151 }
20153 /* Deduce the value of template parameters. TPARMS is the (innermost)
20154 set of template parameters to a template. TARGS is the bindings
20155 for those template parameters, as determined thus far; TARGS may
20156 include template arguments for outer levels of template parameters
20157 as well. PARM is a parameter to a template function, or a
20158 subcomponent of that parameter; ARG is the corresponding argument.
20159 This function attempts to match PARM with ARG in a manner
20160 consistent with the existing assignments in TARGS. If more values
20161 are deduced, then TARGS is updated.
20163 Returns 0 if the type deduction succeeds, 1 otherwise. The
20164 parameter STRICT is a bitwise or of the following flags:
20166 UNIFY_ALLOW_NONE:
20167 Require an exact match between PARM and ARG.
20168 UNIFY_ALLOW_MORE_CV_QUAL:
20169 Allow the deduced ARG to be more cv-qualified (by qualification
20170 conversion) than ARG.
20171 UNIFY_ALLOW_LESS_CV_QUAL:
20172 Allow the deduced ARG to be less cv-qualified than ARG.
20173 UNIFY_ALLOW_DERIVED:
20174 Allow the deduced ARG to be a template base class of ARG,
20175 or a pointer to a template base class of the type pointed to by
20176 ARG.
20177 UNIFY_ALLOW_INTEGER:
20178 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20179 case for more information.
20180 UNIFY_ALLOW_OUTER_LEVEL:
20181 This is the outermost level of a deduction. Used to determine validity
20182 of qualification conversions. A valid qualification conversion must
20183 have const qualified pointers leading up to the inner type which
20184 requires additional CV quals, except at the outer level, where const
20185 is not required [conv.qual]. It would be normal to set this flag in
20186 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20187 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20188 This is the outermost level of a deduction, and PARM can be more CV
20189 qualified at this point.
20190 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20191 This is the outermost level of a deduction, and PARM can be less CV
20192 qualified at this point. */
20194 static int
20197 {
20199 tree targ;
20200 tree tparm;
20202 tsubst_flags_t complain = (explain_p
20203 ? tf_warning_or_error
20206 /* I don't think this will do the right thing with respect to types.
20207 But the only case I've seen it in so far has been array bounds, where
20208 signedness is the only information lost, and I think that will be
20209 okay. */
20217 /* We can't deduce anything from this, but we might get all the
20218 template args from other function args. */
20224 /* If PARM uses template parameters, then we can't bail out here,
20225 even if ARG == PARM, since we won't record unifications for the
20226 template parameters. We might need them if we're trying to
20227 figure out which of two things is more specialized. */
20231 /* Handle init lists early, so the rest of the function can assume
20232 we're dealing with a type. */
20234 {
20239 /* Replace T with std::initializer_list<T> for deduction. */
20246 /* We can only deduce from an initializer list argument if the
20247 parameter is std::initializer_list or an array; otherwise this
20248 is a non-deduced context. */
20253 else
20254 {
20256 /* Deduction is defined in terms of a single type, so just punt
20257 on the (bizarre) std::initializer_list<T...>. */
20260 }
20263 {
20270 {
20274 /* It should only be possible to get here for a call. */
20276 elt_strict |= maybe_adjust_types_for_deduction
20279 }
20282 explain_p);
20283 }
20287 {
20288 /* Also deduce from the length of the initializer list. */
20295 }
20297 /* If the std::initializer_list<T> deduction worked, replace the
20298 deduced A with std::initializer_list<A>. */
20300 {
20305 }
20307 }
20309 /* If parm and arg aren't the same kind of thing (template, type, or
20310 expression), fail early. */
20314 /* Immediately reject some pairs that won't unify because of
20315 cv-qualification mismatches. */
20318 /* It is the elements of the array which hold the cv quals of an array
20319 type, and the elements might be template type parms. We'll check
20320 when we recurse. */
20322 /* We check the cv-qualifiers when unifying with template type
20323 parameters below. We want to allow ARG `const T' to unify with
20324 PARM `T' for example, when computing which of two templates
20325 is more specialized, for example. */
20339 {
20343 /* In a type which contains a nested-name-specifier, template
20344 argument values cannot be deduced for template parameters used
20345 within the nested-name-specifier. */
20357 /* The PARM is not one we're trying to unify. Just check
20358 to see if it matches ARG. */
20359 {
20364 else
20366 }
20373 /* Check for mixed types and values. */
20381 {
20384 {
20385 /* First try to match ARG directly. */
20387 explain_p);
20389 {
20390 /* Otherwise, look for a suitable base of ARG, as below. */
20397 }
20398 }
20399 /* ARG must be constructed from a template class or a template
20400 template parameter. */
20405 /* Deduce arguments T, i from TT<T> or TT<i>. */
20411 /* Fall through to deduce template name. */
20412 }
20416 {
20417 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20419 /* Simple cases: Value already set, does match or doesn't. */
20424 }
20425 else
20426 {
20427 /* If PARM is `const T' and ARG is only `int', we don't have
20428 a match unless we are allowing additional qualification.
20429 If ARG is `const int' and PARM is just `T' that's OK;
20430 that binds `const int' to `T'. */
20435 /* Consider the case where ARG is `const volatile int' and
20436 PARM is `const T'. Then, T should be `volatile int'. */
20437 arg = cp_build_qualified_type_real
20442 /* Simple cases: Value already set, does match or doesn't. */
20448 /* Make sure that ARG is not a variable-sized array. (Note
20449 that were talking about variable-sized arrays (like
20450 `int[n]'), rather than arrays of unknown size (like
20451 `int[]').) We'll get very confused by such a type since
20452 the bound of the array is not constant, and therefore
20453 not mangleable. Besides, such types are not allowed in
20454 ISO C++, so we can do as we please here. We do allow
20455 them for 'auto' deduction, since that isn't ABI-exposed. */
20459 /* Strip typedefs as in convert_template_argument. */
20461 }
20463 /* If ARG is a parameter pack or an expansion, we cannot unify
20464 against it unless PARM is also a parameter pack. */
20469 /* If the argument deduction results is a METHOD_TYPE,
20470 then there is a problem.
20471 METHOD_TYPE doesn't map to any real C++ type the result of
20472 the deduction can not be of that type. */
20486 {
20487 /* The PARM is not one we're trying to unify. Just check
20488 to see if it matches ARG. */
20494 }
20500 {
20505 }
20508 /* We deduce from array bounds in try_array_deduction. */
20512 {
20517 }
20519 /* [temp.deduct.type] If, in the declaration of a function template
20520 with a non-type template-parameter, the non-type
20521 template-parameter is used in an expression in the function
20522 parameter-list and, if the corresponding template-argument is
20523 deduced, the template-argument type shall match the type of the
20524 template-parameter exactly, except that a template-argument
20525 deduced from an array bound may be of any integral type.
20526 The non-type parameter might use already deduced type parameters. */
20529 {
20533 }
20536 /* Template-parameter dependent expression. Just accept it for now.
20537 It will later be processed in convert_template_argument. */
20538 ;
20543 /* Convert the ARG to the type of PARM; the deduced non-type
20544 template argument must exactly match the types of the
20545 corresponding parameter. */
20548 /* We haven't deduced the type of this parameter yet. Try again
20549 later. */
20551 else
20554 /* If ARG is a parameter pack or an expansion, we cannot unify
20555 against it unless PARM is also a parameter pack. */
20560 {
20563 }
20568 {
20569 /* A pointer-to-member constant can be unified only with
20570 another constant. */
20574 /* Just unify the class member. It would be useless (and possibly
20575 wrong, depending on the strict flags) to unify also
20576 PTRMEM_CST_CLASS, because we want to be sure that both parm and
20577 arg refer to the same variable, even if through different
20578 classes. For instance:
20580 struct A { int x; };
20581 struct B : A { };
20583 Unification of &A::x and &B::x must succeed. */
20586 }
20589 {
20593 /* [temp.deduct.call]
20595 A can be another pointer or pointer to member type that can
20596 be converted to the deduced A via a qualification
20597 conversion (_conv.qual_).
20599 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
20600 This will allow for additional cv-qualification of the
20601 pointed-to types if appropriate. */
20604 /* The derived-to-base conversion only persists through one
20605 level of pointers. */
20610 }
20642 /* We have already checked cv-qualification at the top of the
20643 function. */
20647 /* As far as unification is concerned, this wins. Later checks
20648 will invalidate it if necessary. */
20651 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
20652 /* Type INTEGER_CST can come from ordinary constant template args. */
20664 {
20674 /* Check for pack expansions in the parameters. */
20676 {
20678 {
20680 /* We can unify against something with a trailing
20681 parameter pack. */
20683 else
20684 /* [temp.deduct.type]/9: If the template argument list of
20685 P contains a pack expansion that is not the last
20686 template argument, the entire template argument list
20687 is a non-deduced context. */
20689 }
20690 }
20692 /* If we don't have enough arguments to satisfy the parameters
20693 (not counting the pack expression at the end), or we have
20694 too many arguments for a parameter list that doesn't end in
20695 a pack expression, we can't unify. */
20701 /* Unify all of the parameters that precede the (optional)
20702 pack expression. */
20704 {
20709 }
20712 DEDUCE_EXACT,
20715 }
20723 {
20731 }
20736 {
20740 {
20741 /* First, we try to unify the PARM and ARG directly. */
20746 {
20747 /* Fallback to the special case allowed in
20748 [temp.deduct.call]:
20750 If P is a class, and P has the form
20751 template-id, then A can be a derived class of
20752 the deduced A. Likewise, if P is a pointer to
20753 a class of the form template-id, A can be a
20754 pointer to a derived class pointed to by the
20755 deduced A. */
20761 {
20762 /* Don't give the derived diagnostic if we're
20763 already dealing with the same template. */
20764 bool same_template
20770 }
20771 }
20772 }
20776 /* Perhaps PARM is something like S<U> and ARG is S<int>.
20777 Then, we should unify `int' and `U'. */
20779 else
20780 /* There's no chance of unification succeeding. */
20785 }
20792 {
20795 tree a;
20801 /* CV qualifications for methods can never be deduced, they must
20802 match exactly. We need to check them explicitly here,
20803 because type_unification_real treats them as any other
20804 cv-qualified parameter. */
20806 && (!check_cv_quals_for_unify
20834 {
20846 }
20849 }
20852 /* Unify a pointer to member with a pointer to member function, which
20853 deduces the type of the member as a function type. */
20855 {
20856 /* Check top-level cv qualifiers */
20864 /* Determine the type of the function we are unifying against. */
20868 }
20887 /* Matched cases are handled by the ARG == PARM test above. */
20891 /* We might get a variable as a non-type template argument in parm if the
20892 corresponding parameter is type-dependent. Make any necessary
20893 adjustments based on whether arg is a reference. */
20897 {
20902 }
20903 /* Now use the normal expression code to check whether they match. */
20914 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
20915 or UNDERLYING_TYPE nodes. */
20919 /* Unification fails if we hit an error node. */
20924 {
20934 }
20935 /* FALLTHRU */
20938 /* An unresolved overload is a nondeduced context. */
20942 expr:
20943 /* We must be looking at an expression. This can happen with
20944 something like:
20946 template <int I>
20947 void foo(S<I>, S<I + 2>);
20949 This is a "nondeduced context":
20951 [deduct.type]
20953 The nondeduced contexts are:
20955 --A type that is a template-id in which one or more of
20956 the template-arguments is an expression that references
20957 a template-parameter.
20959 In these cases, we assume deduction succeeded, but don't
20960 actually infer any unifications. */
20965 else
20967 }
20968 }
20969 #undef RECUR_AND_CHECK_FAILURE
20970 \f
20971 /* Note that DECL can be defined in this translation unit, if
20972 required. */
20974 static void
20976 {
20977 tree clone;
20981 }
20983 /* Called if RESULT is explicitly instantiated, or is a member of an
20984 explicitly instantiated class. */
20986 void
20988 {
20991 /* If this entity has already been written out, it's too late to
20992 make any modifications. */
20996 /* For anonymous namespace we don't need to do anything. */
20998 {
21001 }
21004 /* The TREE_PUBLIC flag for function declarations will have been
21005 set correctly by tsubst. */
21008 /* This might have been set by an earlier implicit instantiation. */
21013 else
21014 {
21017 /* Always make artificials weak. */
21020 /* For WIN32 we also want to put explicit instantiations in
21021 linkonce sections. */
21024 }
21026 /* If EXTERN_P, then this function will not be emitted -- unless
21027 followed by an explicit instantiation, at which point its linkage
21028 will be adjusted. If !EXTERN_P, then this function will be
21029 emitted here. In neither circumstance do we want
21030 import_export_decl to adjust the linkage. */
21032 }
21034 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21035 important template arguments. If any are missing, we check whether
21036 they're important by using error_mark_node for substituting into any
21037 args that were used for partial ordering (the ones between ARGS and END)
21038 and seeing if it bubbles up. */
21040 static bool
21042 {
21047 {
21050 }
21052 {
21056 }
21058 }
21060 /* Given two function templates PAT1 and PAT2, return:
21062 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21063 -1 if PAT2 is more specialized than PAT1.
21064 0 if neither is more specialized.
21066 LEN indicates the number of parameters we should consider
21067 (defaulted parameters should not be considered).
21069 The 1998 std underspecified function template partial ordering, and
21070 DR214 addresses the issue. We take pairs of arguments, one from
21071 each of the templates, and deduce them against each other. One of
21072 the templates will be more specialized if all the *other*
21073 template's arguments deduce against its arguments and at least one
21074 of its arguments *does* *not* deduce against the other template's
21075 corresponding argument. Deduction is done as for class templates.
21076 The arguments used in deduction have reference and top level cv
21077 qualifiers removed. Iff both arguments were originally reference
21078 types *and* deduction succeeds in both directions, an lvalue reference
21079 wins against an rvalue reference and otherwise the template
21080 with the more cv-qualified argument wins for that pairing (if
21081 neither is more cv-qualified, they both are equal). Unlike regular
21082 deduction, after all the arguments have been deduced in this way,
21083 we do *not* verify the deduced template argument values can be
21084 substituted into non-deduced contexts.
21086 The logic can be a bit confusing here, because we look at deduce1 and
21087 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21088 can find template arguments for pat1 to make arg1 look like arg2, that
21089 means that arg2 is at least as specialized as arg1. */
21091 int
21093 {
21106 /* Remove the this parameter from non-static member functions. If
21107 one is a non-static member function and the other is not a static
21108 member function, remove the first parameter from that function
21109 also. This situation occurs for operator functions where we
21110 locate both a member function (with this pointer) and non-member
21111 operator (with explicit first operand). */
21113 {
21118 }
21120 {
21123 {
21124 len--;
21126 }
21127 }
21129 /* If only one is a conversion operator, they are unordered. */
21133 /* Consider the return type for a conversion function */
21135 {
21138 len++;
21139 }
21141 processing_template_decl++;
21147 /* Stop when an ellipsis is seen. */
21149 {
21160 {
21161 /* When both arguments are pack expansions, we need only
21162 unify the patterns themselves. */
21166 /* This is the last comparison we need to do. */
21168 }
21171 {
21175 }
21178 {
21182 }
21188 {
21194 /* Setup the parameter vector, which contains only ARG1. */
21197 /* Setup the argument vector, which contains the remaining
21198 arguments. */
21207 /* We cannot deduce in the other direction, because ARG1 is
21208 a pack expansion but ARG2 is not. */
21210 }
21212 {
21218 /* Setup the parameter vector, which contains only ARG1. */
21221 /* Setup the argument vector, which contains the remaining
21222 arguments. */
21231 /* We cannot deduce in the other direction, because ARG2 is
21232 a pack expansion but ARG1 is not.*/
21234 }
21236 else
21237 {
21238 /* The normal case, where neither argument is a pack
21239 expansion. */
21246 }
21248 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21249 arg2, then arg2 is not as specialized as arg1. */
21255 /* "If, for a given type, deduction succeeds in both directions
21256 (i.e., the types are identical after the transformations above)
21257 and both P and A were reference types (before being replaced with
21258 the type referred to above):
21259 - if the type from the argument template was an lvalue reference and
21260 the type from the parameter template was not, the argument type is
21261 considered to be more specialized than the other; otherwise,
21262 - if the type from the argument template is more cv-qualified
21263 than the type from the parameter template (as described above),
21264 the argument type is considered to be more specialized than the other;
21265 otherwise,
21266 - neither type is more specialized than the other." */
21269 {
21271 {
21274 else
21276 }
21278 {
21283 }
21284 }
21287 /* We've failed to deduce something in either direction.
21288 These must be unordered. */
21293 /* We have already processed all of the arguments in our
21294 handing of the pack expansion type. */
21299 }
21301 /* "In most cases, all template parameters must have values in order for
21302 deduction to succeed, but for partial ordering purposes a template
21303 parameter may remain without a value provided it is not used in the
21304 types being used for partial ordering."
21306 Thus, if we are missing any of the targs1 we need to substitute into
21307 origs1, then pat2 is not as specialized as pat1. This can happen when
21308 there is a nondeduced context. */
21314 processing_template_decl--;
21316 /* If both deductions succeed, the partial ordering selects the more
21317 constrained template. */
21319 {
21324 }
21326 /* All things being equal, if the next argument is a pack expansion
21327 for one function but not for the other, prefer the
21328 non-variadic function. FIXME this is bogus; see c++/41958. */
21332 {
21335 }
21341 else
21343 }
21345 /* Determine which of two partial specializations of TMPL is more
21346 specialized.
21348 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21349 to the first partial specialization. The TREE_PURPOSE is the
21350 innermost set of template parameters for the partial
21351 specialization. PAT2 is similar, but for the second template.
21353 Return 1 if the first partial specialization is more specialized;
21354 -1 if the second is more specialized; 0 if neither is more
21355 specialized.
21357 See [temp.class.order] for information about determining which of
21358 two templates is more specialized. */
21360 static int
21362 {
21363 tree targs;
21372 /* Just like what happens for functions, if we are ordering between
21373 different template specializations, we may encounter dependent
21374 types in the arguments, and we need our dependency check functions
21375 to behave correctly. */
21379 {
21382 }
21386 {
21389 }
21392 /* If both deductions succeed, the partial ordering selects the more
21393 constrained template. */
21397 /* In the case of a tie where at least one of the templates
21398 has a parameter pack at the end, the template with the most
21399 non-packed parameters wins. */
21401 && any_deductions
21404 {
21410 /* We don't count the pack expansion at the end. */
21420 }
21423 }
21425 /* Return the template arguments that will produce the function signature
21426 DECL from the function template FN, with the explicit template
21427 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21428 also match. Return NULL_TREE if no satisfactory arguments could be
21429 found. */
21431 static tree
21433 {
21437 tree decl_arg_types;
21440 tree arg;
21444 /* Never do unification on the 'this' parameter. */
21465 }
21467 /* Return the innermost template arguments that, when applied to a partial
21468 specialization SPEC_TMPL of TMPL, yield the ARGS.
21470 For example, suppose we have:
21472 template <class T, class U> struct S {};
21473 template <class T> struct S<T*, int> {};
21475 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21476 partial specialization and the ARGS will be {double*, int}. The resulting
21477 vector will be {double}, indicating that `T' is bound to `double'. */
21479 static tree
21481 {
21483 tree spec_args
21486 tree deduced_args;
21487 tree innermost_deduced_args;
21491 {
21495 innermost_deduced_args);
21496 }
21497 else
21501 again:
21510 {
21512 {
21518 }
21520 }
21524 {
21527 }
21529 /* Verify that nondeduced template arguments agree with the type
21530 obtained from argument deduction.
21532 For example:
21534 struct A { typedef int X; };
21535 template <class T, class U> struct C {};
21536 template <class T> struct C<T, typename T::X> {};
21538 Then with the instantiation `C<A, int>', we can deduce that
21539 `T' is `A' but unify () does not check whether `typename T::X'
21540 is `int'. */
21549 /* We only need to check the innermost arguments; the other
21550 arguments will always agree. */
21555 /* Now that we have bindings for all of the template arguments,
21556 ensure that the arguments deduced for the template template
21557 parameters have compatible template parameter lists. See the use
21558 of template_template_parm_bindings_ok_p in fn_type_unification
21559 for more information. */
21564 }
21566 // Compare two function templates T1 and T2 by deducing bindings
21567 // from one against the other. If both deductions succeed, compare
21568 // constraints to see which is more constrained.
21569 static int
21571 {
21576 {
21579 }
21582 {
21585 }
21587 // If both deductions succeed, then one may be more constrained.
21592 }
21594 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
21595 Return the TREE_LIST node with the most specialized template, if
21596 any. If there is no most specialized template, the error_mark_node
21597 is returned.
21599 Note that this function does not look at, or modify, the
21600 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
21601 returned is one of the elements of INSTANTIATIONS, callers may
21602 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
21603 and retrieve it from the value returned. */
21605 tree
21607 {
21614 {
21619 {
21620 /* Equally specialized, move to next function. If there
21621 is no next function, nothing's most specialized. */
21626 }
21627 }
21630 /* Now verify that champ is better than everything earlier in the
21631 instantiation list. */
21634 {
21637 }
21638 }
21640 processing_template_decl--;
21646 }
21648 /* If DECL is a specialization of some template, return the most
21649 general such template. Otherwise, returns NULL_TREE.
21651 For example, given:
21653 template <class T> struct S { template <class U> void f(U); };
21655 if TMPL is `template <class U> void S<int>::f(U)' this will return
21656 the full template. This function will not trace past partial
21657 specializations, however. For example, given in addition:
21659 template <class T> struct S<T*> { template <class U> void f(U); };
21661 if TMPL is `template <class U> void S<int*>::f(U)' this will return
21662 `template <class T> template <class U> S<T*>::f(U)'. */
21664 tree
21666 {
21668 {
21671 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
21672 template friend, or a FIELD_DECL for a capture pack. */
21675 }
21677 /* Look for more and more general templates. */
21679 {
21680 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
21681 (See cp-tree.h for details.) */
21690 /* Stop if we run into an explicitly specialized class template. */
21697 }
21700 }
21702 /* Return the most specialized of the template partial specializations
21703 which can produce TARGET, a specialization of some class or variable
21704 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
21705 a TEMPLATE_DECL node corresponding to the partial specialization, while
21706 the TREE_PURPOSE is the set of template arguments that must be
21707 substituted into the template pattern in order to generate TARGET.
21709 If the choice of partial specialization is ambiguous, a diagnostic
21710 is issued, and the error_mark_node is returned. If there are no
21711 partial specializations matching TARGET, then NULL_TREE is
21712 returned, indicating that the primary template should be used. */
21714 static tree
21716 {
21718 tree t;
21719 tree champ;
21726 {
21730 }
21732 {
21735 }
21737 {
21741 }
21742 else
21747 /* For determining which partial specialization to use, only the
21748 innermost args are interesting. */
21750 {
21753 }
21756 {
21757 tree spec_args;
21761 {
21762 /* Substitute in the template args from the enclosing class. */
21766 }
21773 {
21777 /* Keep the candidate only if the constraints are satisfied,
21778 or if we're not compiling with concepts. */
21781 {
21784 }
21785 }
21786 }
21796 {
21799 ;
21800 else
21801 {
21803 {
21806 {
21809 }
21810 }
21812 }
21813 }
21817 {
21820 {
21823 }
21824 }
21827 {
21834 else
21838 {
21843 }
21846 }
21849 }
21851 /* Explicitly instantiate DECL. */
21853 void
21855 {
21860 /* An error occurred, for which grokdeclarator has already issued
21861 an appropriate message. */
21864 {
21867 }
21873 {
21874 /* There is an asymmetry here in the way VAR_DECLs and
21875 FUNCTION_DECLs are handled by grokdeclarator. In the case of
21876 the latter, the DECL we get back will be marked as a
21877 template instantiation, and the appropriate
21878 DECL_TEMPLATE_INFO will be set up. This does not happen for
21879 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
21880 should handle VAR_DECLs as it currently handles
21881 FUNCTION_DECLs. */
21883 {
21886 }
21889 {
21892 }
21894 {
21899 }
21900 }
21902 {
21905 }
21906 else
21909 /* Check for various error cases. Note that if the explicit
21910 instantiation is valid the RESULT will currently be marked as an
21911 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
21912 until we get here. */
21915 {
21916 /* DR 259 [temp.spec].
21918 Both an explicit instantiation and a declaration of an explicit
21919 specialization shall not appear in a program unless the explicit
21920 instantiation follows a declaration of the explicit specialization.
21922 For a given set of template parameters, if an explicit
21923 instantiation of a template appears after a declaration of an
21924 explicit specialization for that template, the explicit
21925 instantiation has no effect. */
21927 }
21929 {
21930 /* [temp.spec]
21932 No program shall explicitly instantiate any template more
21933 than once.
21935 We check DECL_NOT_REALLY_EXTERN so as not to complain when
21936 the first instantiation was `extern' and the second is not,
21937 and EXTERN_P for the opposite case. */
21940 /* If an "extern" explicit instantiation follows an ordinary
21941 explicit instantiation, the template is instantiated. */
21944 }
21946 {
21949 }
21951 {
21954 }
21957 ;
21959 {
21962 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
21965 }
21966 else
21974 }
21976 static void
21978 {
21984 {
21987 }
21988 }
21990 /* Called from do_type_instantiation through binding_table_foreach to
21991 do recursive instantiation for the type bound in ENTRY. */
21992 static void
21994 {
22000 }
22002 /* Called from do_type_instantiation to instantiate a member
22003 (a member function or a static member variable) of an
22004 explicitly instantiated class template. */
22005 static void
22007 {
22012 }
22014 /* Perform an explicit instantiation of template class T. STORAGE, if
22015 non-null, is the RID for extern, inline or static. COMPLAIN is
22016 nonzero if this is called from the parser, zero if called recursively,
22017 since the standard is unclear (as detailed below). */
22019 void
22021 {
22031 {
22032 tree tmpl =
22036 else
22039 }
22044 {
22047 t);
22049 }
22052 {
22054 {
22056 {
22059 "ISO C++ 1998 forbids the use of %<extern%> on "
22061 }
22062 else
22064 "ISO C++ forbids the use of %qE"
22066 }
22074 else
22075 {
22077 storage);
22079 }
22080 }
22083 {
22084 /* DR 259 [temp.spec].
22086 Both an explicit instantiation and a declaration of an explicit
22087 specialization shall not appear in a program unless the explicit
22088 instantiation follows a declaration of the explicit specialization.
22090 For a given set of template parameters, if an explicit
22091 instantiation of a template appears after a declaration of an
22092 explicit specialization for that template, the explicit
22093 instantiation has no effect. */
22095 }
22097 {
22098 /* [temp.spec]
22100 No program shall explicitly instantiate any template more
22101 than once.
22103 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22104 instantiation was `extern'. If EXTERN_P then the second is.
22105 These cases are OK. */
22112 /* If we've already instantiated the template, just return now. */
22115 }
22123 {
22124 tree tmp;
22126 /* In contrast to implicit instantiation, where only the
22127 declarations, and not the definitions, of members are
22128 instantiated, we have here:
22130 [temp.explicit]
22132 The explicit instantiation of a class template specialization
22133 implies the instantiation of all of its members not
22134 previously explicitly specialized in the translation unit
22135 containing the explicit instantiation.
22137 Of course, we can't instantiate member template classes, since
22138 we don't have any arguments for them. Note that the standard
22139 is unclear on whether the instantiation of the members are
22140 *explicit* instantiations or not. However, the most natural
22141 interpretation is that it should be an explicit instantiation. */
22157 }
22158 }
22160 /* Given a function DECL, which is a specialization of TMPL, modify
22161 DECL to be a re-instantiation of TMPL with the same template
22162 arguments. TMPL should be the template into which tsubst'ing
22163 should occur for DECL, not the most general template.
22165 One reason for doing this is a scenario like this:
22167 template <class T>
22168 void f(const T&, int i);
22170 void g() { f(3, 7); }
22172 template <class T>
22173 void f(const T& t, const int i) { }
22175 Note that when the template is first instantiated, with
22176 instantiate_template, the resulting DECL will have no name for the
22177 first parameter, and the wrong type for the second. So, when we go
22178 to instantiate the DECL, we regenerate it. */
22180 static void
22182 {
22183 /* The arguments used to instantiate DECL, from the most general
22184 template. */
22185 tree code_pattern;
22189 /* Make sure that we can see identifiers, and compute access
22190 correctly. */
22194 {
22195 tree decl_parm;
22196 tree pattern_parm;
22197 tree specs;
22211 specs);
22213 /* Merge parameter declarations. */
22216 pattern_parm
22220 {
22221 tree parm_type;
22222 tree attributes;
22227 NULL_TREE);
22233 {
22236 }
22239 }
22240 /* Merge any parameters that match with the function parameter
22241 pack. */
22243 {
22245 tree expanded_types;
22246 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22247 the parameters in this function parameter pack. */
22252 {
22253 tree parm_type;
22254 tree attributes;
22257 /* Rename the parameter to include the index. */
22266 {
22269 }
22271 }
22272 }
22273 /* Merge additional specifiers from the CODE_PATTERN. */
22277 }
22279 {
22287 }
22288 else
22292 }
22294 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22295 substituted to get DECL. */
22297 tree
22299 {
22302 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22303 for the instantiation. This is not always the most general
22304 template. Consider, for example:
22306 template <class T>
22307 struct S { template <class U> void f();
22308 template <> void f<int>(); };
22310 and an instantiation of S<double>::f<int>. We want TD to be the
22311 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22313 more general template. */
22315 /* We must also deal with friend templates. Given:
22317 template <class T> struct S {
22318 template <class U> friend void f() {};
22319 };
22321 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22322 so far as the language is concerned, but that's still
22323 where we get the pattern for the instantiation from. On
22324 other hand, if the definition comes outside the class, say:
22326 template <class T> struct S {
22327 template <class U> friend void f();
22328 };
22329 template <class U> friend void f() {}
22331 we don't need to look any further. That's what the check for
22332 DECL_INITIAL is for. */
22336 {
22337 /* The present template, TD, should not be a definition. If it
22338 were a definition, we should be using it! Note that we
22339 cannot restructure the loop to just keep going until we find
22340 a template with a definition, since that might go too far if
22341 a specialization was declared, but not defined. */
22343 /* Fetch the more general template. */
22345 }
22348 }
22350 /* Returns true if we need to instantiate this template instance even if we
22351 know we aren't going to emit it. */
22353 bool
22355 {
22356 /* We always instantiate inline functions so that we can inline them. An
22357 explicit instantiation declaration prohibits implicit instantiation of
22358 non-inline functions. With high levels of optimization, we would
22359 normally inline non-inline functions -- but we're not allowed to do
22360 that for "extern template" functions. Therefore, we check
22361 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22365 /* And we need to instantiate static data members so that
22366 their initializers are available in integral constant
22367 expressions. */
22370 }
22372 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22373 instantiate it now, modifying TREE_TYPE (fn). */
22375 void
22377 {
22380 /* Don't instantiate a noexcept-specification from template context. */
22395 {
22399 {
22414 }
22415 else
22419 }
22422 {
22425 else
22427 }
22428 }
22430 /* Produce the definition of D, a _DECL generated from a template. If
22431 DEFER_OK is true, then we don't have to actually do the
22432 instantiation now; we just have to do it sometime. Normally it is
22433 an error if this is an explicit instantiation but D is undefined.
22434 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22435 instantiated class template. */
22437 tree
22439 {
22441 tree gen_args;
22442 tree args;
22443 tree td;
22444 tree code_pattern;
22445 tree spec;
22446 tree gen_tmpl;
22454 /* This function should only be used to instantiate templates for
22455 functions and static member variables. */
22458 /* A concept is never instantiated. */
22461 /* Variables are never deferred; if instantiation is required, they
22462 are instantiated right away. That allows for better code in the
22463 case that an expression refers to the value of the variable --
22464 if the variable has a constant value the referring expression can
22465 take advantage of that fact. */
22469 /* Don't instantiate cloned functions. Instead, instantiate the
22470 functions they cloned. */
22478 /* D has already been instantiated or explicitly specialized, so
22479 there's nothing for us to do here.
22481 It might seem reasonable to check whether or not D is an explicit
22482 instantiation, and, if so, stop here. But when an explicit
22483 instantiation is deferred until the end of the compilation,
22484 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22485 the instantiation. */
22488 /* Check to see whether we know that this template will be
22489 instantiated in some other file, as with "extern template"
22490 extension. */
22493 /* In general, we do not instantiate such templates. */
22501 /* We should already have the extra args. */
22504 /* And what's in the hash table should match D. */
22508 /* This needs to happen before any tsubsting. */
22514 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
22515 for the instantiation. */
22520 {
22521 /* Look up an explicit specialization, if any. */
22525 {
22528 }
22529 }
22533 /* We should never be trying to instantiate a member of a class
22534 template or partial specialization. */
22539 /* In the case of a friend template whose definition is provided
22540 outside the class, we may have too many arguments. Drop the
22541 ones we don't need. The same is true for specializations. */
22542 args = get_innermost_template_args
22546 {
22552 }
22553 else
22554 {
22559 else
22561 }
22563 /* We may be in the middle of deferred access check. Disable it now. */
22566 /* Unless an explicit instantiation directive has already determined
22567 the linkage of D, remember that a definition is available for
22568 this entity. */
22578 /* If D is a member of an explicitly instantiated class template,
22579 and no definition is available, treat it like an implicit
22580 instantiation. */
22583 {
22584 /* Leave linkage flags alone on instantiations with anonymous
22585 visibility. */
22587 {
22590 }
22592 }
22594 /* Defer all other templates, unless we have been explicitly
22595 forbidden from doing so. */
22597 template. */
22598 ! pattern_defined
22599 /* If it's OK to postpone instantiation, do so. */
22600 || defer_ok
22601 /* If this is a static data member that will be defined
22602 elsewhere, we don't want to instantiate the entire data
22603 member, but we do want to instantiate the initializer so that
22604 we can substitute that elsewhere. */
22606 /* Handle here a deleted function too, avoid generating
22607 its body (c++/61080). */
22609 {
22610 /* The definition of the static data member is now required so
22611 we must substitute the initializer. */
22615 {
22616 tree ns;
22617 tree init;
22626 args,
22629 /* If instantiating the initializer involved instantiating this
22630 again, don't call cp_finish_decl twice. */
22632 {
22633 /* Make sure the initializer is still constant, in case of
22634 circular dependency (template/instantiate6.C). */
22635 const_init
22639 LOOKUP_ONLYCONVERTING);
22640 }
22644 }
22646 /* We restore the source position here because it's used by
22647 add_pending_template. */
22653 /* [temp.explicit]
22655 The definition of a non-exported function template, a
22656 non-exported member function template, or a non-exported
22657 member function or static data member of a class template
22658 shall be present in every translation unit in which it is
22659 explicitly instantiated. */
22663 /* If we're in unevaluated context, we just wanted to get the
22664 constant value; this isn't an odr use, so don't queue
22665 a full instantiation. */
22668 /* ??? Historically, we have instantiated inline functions, even
22669 when marked as "extern template". */
22673 }
22674 /* Tell the repository that D is available in this translation unit
22675 -- and see if it is supposed to be instantiated here. */
22677 {
22678 /* In a PCH file, despite the fact that the repository hasn't
22679 requested instantiation in the PCH it is still possible that
22680 an instantiation will be required in a file that includes the
22681 PCH. */
22684 /* Instantiate inline functions so that the inliner can do its
22685 job, even though we'll not be emitting a copy of this
22686 function. */
22689 }
22692 tree fn_context;
22703 else
22704 {
22708 }
22710 /* Mark D as instantiated so that recursive calls to
22711 instantiate_decl do not try to instantiate it again. */
22714 /* Regenerate the declaration in case the template has been modified
22715 by a subsequent redeclaration. */
22718 /* We already set the file and line above. Reset them now in case
22719 they changed as a result of calling regenerate_decl_from_template. */
22723 {
22724 tree init;
22727 /* Clear out DECL_RTL; whatever was there before may not be right
22728 since we've reset the type of the declaration. */
22732 /* The initializer is placed in DECL_INITIAL by
22733 regenerate_decl_from_template so we don't need to
22734 push/pop_access_scope again here. Pull it out so that
22735 cp_finish_decl can process it. */
22740 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
22741 initializer. That function will defer actual emission until
22742 we have a chance to determine linkage. */
22745 /* Enter the scope of D so that access-checking works correctly. */
22758 }
22762 {
22764 tree tmpl_parm;
22765 tree spec_parm;
22769 /* Save away the current list, in case we are instantiating one
22770 template from within the body of another. */
22773 /* Set up the list of local specializations. */
22776 /* Set up context. */
22780 else
22781 {
22783 {
22784 /* When instantiating a lambda's templated function
22785 operator, we need to push the non-lambda class scope
22786 of the lambda itself so that the nested function
22787 stack is sufficiently correct to deal with this
22788 capture. */
22790 do
22795 }
22797 }
22799 /* Some typedefs referenced from within the template code need to be
22800 access checked at template instantiation time, i.e now. These
22801 types were added to the template at parsing time. Let's get those
22802 and perform the access checks then. */
22804 args);
22806 /* Create substitution entries for the parameters. */
22810 {
22814 }
22816 {
22818 {
22821 }
22822 else
22823 {
22824 /* Register the (value) argument pack as a specialization of
22825 TMPL_PARM, then move on. */
22828 }
22829 }
22832 /* Substitute into the body of the function. */
22836 else
22837 {
22842 /* Set the current input_location to the end of the function
22843 so that finish_function knows where we are. */
22844 input_location
22847 /* Remember if we saw an infinite loop in the template. */
22848 current_function_infinite_loop
22850 }
22852 /* We don't need the local specializations any more. */
22856 /* Finish the function. */
22860 else
22861 {
22864 }
22870 }
22872 /* We're not deferring instantiation any more. */
22877 else
22883 out:
22892 }
22894 /* Run through the list of templates that we wish we could
22895 instantiate, and instantiate any we can. RETRIES is the
22896 number of times we retry pending template instantiation. */
22898 void
22900 {
22904 /* Instantiating templates may trigger vtable generation. This in turn
22905 may require further template instantiations. We place a limit here
22906 to avoid infinite loop. */
22908 {
22912 "template instantiation depth exceeds maximum of %d"
22913 " instantiating %q+D, possibly from virtual table generation"
22917 /* Pretend that we defined it. */
22920 }
22922 do
22923 {
22928 {
22933 {
22934 tree fn;
22937 {
22941 fn;
22949 }
22952 }
22953 else
22954 {
22957 {
22958 instantiation
22964 }
22968 }
22971 /* If INSTANTIATION has been instantiated, then we don't
22972 need to consider it again in the future. */
22974 else
22975 {
22978 }
22981 }
22983 }
22987 }
22989 /* Substitute ARGVEC into T, which is a list of initializers for
22990 either base class or a non-static data member. The TREE_PURPOSEs
22991 are DECLs, and the TREE_VALUEs are the initializer values. Used by
22992 instantiate_decl. */
22994 static tree
22996 {
23000 {
23001 tree decl;
23002 tree init;
23008 {
23009 tree expr;
23010 tree arg;
23012 /* Expand the base class expansion type into separate base
23013 classes. */
23015 tf_warning_or_error,
23016 NULL_TREE);
23020 /* We'll be building separate TREE_LISTs of arguments for
23021 each base. */
23027 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23028 expand each argument in the TREE_VALUE of t. */
23035 /* VOID_TYPE_NODE is used to indicate
23036 value-initialization. */
23037 {
23040 }
23041 else
23042 {
23043 /* Substitute parameter packs into each argument in the
23044 TREE_LIST. */
23047 {
23048 tree expanded_exprs;
23050 /* Expand the argument. */
23052 expanded_exprs
23054 tf_warning_or_error,
23055 NULL_TREE);
23059 /* Prepend each of the expanded expressions to the
23060 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23062 {
23067 }
23068 }
23071 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23072 since we built them backwards. */
23074 {
23077 }
23078 }
23079 }
23082 {
23084 {
23088 }
23089 else
23090 {
23091 tree tmp;
23106 /* If we had an initializer but it instantiated to nothing,
23107 value-initialize the object. This will only occur when
23108 the initializer was a pack expansion where the parameter
23109 packs used in that expansion were of length zero. */
23112 }
23115 {
23119 }
23120 }
23121 }
23123 }
23125 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23127 static void
23129 {
23134 else
23136 }
23138 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23139 is the instantiation (which should have been created with
23140 start_enum) and ARGS are the template arguments to use. */
23142 static void
23144 {
23145 tree e;
23151 {
23152 tree value;
23153 tree decl;
23156 /* Note that in a template enum, the TREE_VALUE is the
23157 CONST_DECL, not the corresponding INTEGER_CST. */
23162 /* Give this enumeration constant the correct access. */
23165 /* Actually build the enumerator itself. Here we're assuming that
23166 enumerators can't have dependent attributes. */
23169 }
23179 }
23181 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23182 its type -- but without substituting the innermost set of template
23183 arguments. So, innermost set of template parameters will appear in
23184 the type. */
23186 tree
23188 {
23189 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23191 }
23193 /* Return truthvalue if we're processing a template different from
23194 the last one involved in diagnostics. */
23195 bool
23197 {
23199 }
23201 /* Remember current template involved in diagnostics. */
23202 void
23204 {
23206 }
23210 {
23212 }
23214 /* Return TRUE if current_function_decl is being instantiated, false
23215 otherwise. */
23217 bool
23219 {
23222 }
23224 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23225 type. Return zero for ok, nonzero for disallowed. Issue error and
23226 warning messages under control of COMPLAIN. */
23228 static int
23230 {
23245 /* A bound template template parm could later be instantiated to have a valid
23246 nontype parm type via an alias template. */
23252 {
23255 else
23257 type);
23258 }
23260 }
23262 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23263 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23265 static bool
23267 {
23268 tree scope;
23270 /* [temp.dep.type]
23272 A type is dependent if it is:
23274 -- a template parameter. Template template parameters are types
23275 for us (since TYPE_P holds true for them) so we handle
23276 them here. */
23280 /* -- a qualified-id with a nested-name-specifier which contains a
23281 class-name that names a dependent type or whose unqualified-id
23282 names a dependent type. */
23286 /* An alias template specialization can be dependent even if the
23287 resulting type is not. */
23291 /* -- a cv-qualified type where the cv-unqualified type is
23292 dependent.
23293 No code is necessary for this bullet; the code below handles
23294 cv-qualified types, and we don't want to strip aliases with
23295 TYPE_MAIN_VARIANT because of DR 1558. */
23296 /* -- a compound type constructed from any dependent type. */
23306 {
23307 tree arg_type;
23312 arg_type;
23317 }
23318 /* -- an array type constructed from any dependent type or whose
23319 size is specified by a constant expression that is
23320 value-dependent.
23322 We checked for type- and value-dependence of the bounds in
23323 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23325 {
23330 }
23332 /* -- a template-id in which either the template name is a template
23333 parameter ... */
23336 /* ... or any of the template arguments is a dependent type or
23337 an expression that is type-dependent or value-dependent. */
23339 && (any_dependent_template_arguments_p
23343 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23344 dependent; if the argument of the `typeof' expression is not
23345 type-dependent, then it should already been have resolved. */
23351 /* A template argument pack is dependent if any of its packed
23352 arguments are. */
23354 {
23360 }
23362 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23363 be template parameters. */
23370 /* The standard does not specifically mention types that are local
23371 to template functions or local classes, but they should be
23372 considered dependent too. For example:
23374 template <int I> void f() {
23375 enum E { a = I };
23376 S<sizeof (E)> s;
23377 }
23379 The size of `E' cannot be known until the value of `I' has been
23380 determined. Therefore, `E' must be considered dependent. */
23384 /* Don't use type_dependent_expression_p here, as it can lead
23385 to infinite recursion trying to determine whether a lambda
23386 nested in a lambda is dependent (c++/47687). */
23390 && (any_dependent_template_arguments_p
23394 /* Other types are non-dependent. */
23396 }
23398 /* Returns TRUE if TYPE is dependent, in the sense of
23399 [temp.dep.type]. Note that a NULL type is considered dependent. */
23401 bool
23403 {
23404 /* If there are no template parameters in scope, then there can't be
23405 any dependent types. */
23407 {
23408 /* If we are not processing a template, then nobody should be
23409 providing us with a dependent type. */
23413 }
23415 /* If the type is NULL, we have not computed a type for the entity
23416 in question; in that case, the type is dependent. */
23420 /* Erroneous types can be considered non-dependent. */
23424 /* If we have not already computed the appropriate value for TYPE,
23425 do so now. */
23427 {
23430 }
23433 }
23435 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23436 lookup. In other words, a dependent type that is not the current
23437 instantiation. */
23439 bool
23441 {
23444 }
23446 /* T is a SCOPE_REF; return whether we need to consider it
23447 instantiation-dependent so that we can check access at instantiation
23448 time even though we know which member it resolves to. */
23450 static bool
23452 {
23458 else
23460 }
23462 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23463 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23464 expression. */
23466 /* Note that this predicate is not appropriate for general expressions;
23467 only constant expressions (that satisfy potential_constant_expression)
23468 can be tested for value dependence. */
23470 bool
23472 {
23476 /* A name declared with a dependent type. */
23481 {
23483 /* A dependent member function of the current instantiation. */
23487 /* A dependent member function of the current instantiation. */
23494 /* A name that has not been looked up -- must be dependent. */
23498 /* A non-type template parm. */
23502 /* A non-type template parm. */
23508 /* A constant with literal type and is initialized
23509 with an expression that is value-dependent.
23511 Note that a non-dependent parenthesized initializer will have
23512 already been replaced with its constant value, so if we see
23513 a TREE_LIST it must be dependent. */
23517 /* cp_finish_decl doesn't fold reference initializers. */
23529 /* These expressions are value-dependent if the type to which
23530 the cast occurs is dependent or the expression being casted
23531 is value-dependent. */
23532 {
23538 /* A functional cast has a list of operands. */
23541 {
23542 /* If there are no operands, it must be an expression such
23543 as "int()". This should not happen for aggregate types
23544 because it would form non-constant expressions. */
23549 }
23555 }
23560 /* FALLTHRU */
23563 /* A `sizeof' expression is value-dependent if the operand is
23564 type-dependent or is a pack expansion. */
23573 /* An 'encode' expression is value-dependent if the operand is
23574 type-dependent. */
23583 /* All instantiation-dependent expressions should also be considered
23584 value-dependent. */
23592 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
23593 is value-dependent. */
23594 {
23603 }
23606 {
23610 }
23621 {
23625 }
23628 /* Treat all requires-expressions as value-dependent so
23629 we don't try to fold them. */
23636 {
23643 {
23645 /* In a call to a constexpr member function, look through the
23646 implicit ADDR_EXPR on the object argument so that it doesn't
23647 cause the call to be considered value-dependent. We also
23648 look through it in potential_constant_expression. */
23655 }
23657 }
23660 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
23661 type-dependent. */
23666 {
23668 tree val;
23675 }
23678 /* Treat a GNU statement expression as dependent to avoid crashing
23679 under instantiate_non_dependent_expr; it can't be constant. */
23683 /* A constant expression is value-dependent if any subexpression is
23684 value-dependent. */
23686 {
23693 {
23697 {
23700 /* In some cases, some of the operands may be missing.l
23701 (For example, in the case of PREDECREMENT_EXPR, the
23702 amount to increment by may be missing.) That doesn't
23703 make the expression dependent. */
23706 }
23707 }
23711 }
23713 }
23715 /* The expression is not value-dependent. */
23717 }
23719 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
23720 [temp.dep.expr]. Note that an expression with no type is
23721 considered dependent. Other parts of the compiler arrange for an
23722 expression with type-dependent subexpressions to have no type, so
23723 this function doesn't have to be fully recursive. */
23725 bool
23727 {
23734 /* An unresolved name is always dependent. */
23740 /* A fold expression is type-dependent. */
23747 /* Some expression forms are never type-dependent. */
23761 /* The types of these expressions depends only on the type to which
23762 the cast occurs. */
23771 /* The types of these expressions depends only on the type created
23772 by the expression. */
23775 {
23776 /* For NEW_EXPR tree nodes created inside a template, either
23777 the object type itself or a TREE_LIST may appear as the
23778 operand 1. */
23781 /* This is an array type. We need to check array dimensions
23782 as well. */
23784 || value_dependent_expression_p
23786 else
23788 }
23791 {
23795 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
23796 contains an identifier associated by name lookup with one or more
23797 declarations declared with a dependent type, or...a
23798 nested-name-specifier or qualified-id that names a member of an
23799 unknown specialization. */
23802 }
23812 {
23813 tree elt;
23817 {
23820 }
23822 }
23824 /* A static data member of the current instantiation with incomplete
23825 array type is type-dependent, as the definition and specializations
23826 can have different bounds. */
23833 /* An array of unknown bound depending on a variadic parameter, eg:
23835 template<typename... Args>
23836 void foo (Args... args)
23837 {
23838 int arr[] = { args... };
23839 }
23841 template<int... vals>
23842 void bar ()
23843 {
23844 int arr[] = { vals... };
23845 }
23847 If the array has no length and has an initializer, it must be that
23848 we couldn't determine its length in cp_complete_array_type because
23849 it is dependent. */
23857 /* A function or variable template-id is type-dependent if it has any
23858 dependent template arguments. Note that we only consider the innermost
23859 template arguments here, since those are the ones that come from the
23860 template-id; the template arguments for the enclosing class do not make it
23861 type-dependent, they only make a member function value-dependent. */
23866 && (any_dependent_template_arguments_p
23870 /* Always dependent, on the number of arguments if nothing else. */
23875 {
23880 {
23886 }
23887 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
23892 {
23897 }
23900 {
23907 }
23913 {
23917 }
23919 }
23923 /* Dependent type attributes might not have made it from the decl to
23924 the type yet. */
23930 }
23932 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
23933 type-dependent if the expression refers to a member of the current
23934 instantiation and the type of the referenced member is dependent, or the
23935 class member access expression refers to a member of an unknown
23936 specialization.
23938 This function returns true if the OBJECT in such a class member access
23939 expression is of an unknown specialization. */
23941 bool
23943 {
23944 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
23945 dependent. */
23950 }
23952 /* walk_tree callback function for instantiation_dependent_expression_p,
23953 below. Returns non-zero if a dependent subexpression is found. */
23955 static tree
23958 {
23960 {
23961 /* We don't have to worry about decltype currently because decltype
23962 of an instantiation-dependent expr is a dependent type. This
23963 might change depending on the resolution of DR 1172. */
23966 }
23969 {
23970 /* Don't treat an argument list as dependent just because it has no
23971 TREE_TYPE. */
23979 /* Handle expressions with type operands. */
23984 {
23989 {
23992 else
23993 {
23996 }
23997 }
23999 }
24003 /* In a template, finish_class_member_access_expr creates a
24004 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24005 type-dependent, so that we can check access control at
24006 instantiation time (PR 42277). See also Core issue 1273. */
24013 else
24016 /* Treat statement-expressions as dependent. */
24020 /* Treat requires-expressions as dependent. */
24025 /* Treat calls to function concepts as dependent. */
24031 /* And variable concepts. */
24038 }
24042 else
24044 }
24046 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24047 sense defined by the ABI:
24049 "An expression is instantiation-dependent if it is type-dependent
24050 or value-dependent, or it has a subexpression that is type-dependent
24051 or value-dependent."
24053 Except don't actually check value-dependence for unevaluated expressions,
24054 because in sizeof(i) we don't care about the value of i. Checking
24055 type-dependence will in turn check value-dependence of array bounds/template
24056 arguments as needed. */
24058 bool
24060 {
24061 tree result;
24072 }
24074 /* As above, but also check value-dependence of the expression as a whole. */
24076 bool
24078 {
24081 }
24083 /* Like type_dependent_expression_p, but it also works while not processing
24084 a template definition, i.e. during substitution or mangling. */
24086 bool
24088 {
24094 }
24096 /* Returns TRUE if ARGS contains a type-dependent expression. */
24098 bool
24100 {
24102 tree arg;
24105 {
24108 }
24110 }
24112 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24113 expressions) contains any type-dependent expressions. */
24115 bool
24117 {
24123 }
24125 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24126 expressions) contains any value-dependent expressions. */
24128 bool
24130 {
24136 }
24138 /* Returns TRUE if the ARG (a template argument) is dependent. */
24140 bool
24142 {
24146 /* Assume a template argument that was wrongly written by the user
24147 is dependent. This is consistent with what
24148 any_dependent_template_arguments_p [that calls this function]
24149 does. */
24159 {
24162 /* A member template of a dependent class is not necessarily
24163 type-dependent, but it is a dependent template argument because it
24164 will be a member of an unknown specialization to that template. */
24167 }
24169 {
24173 {
24176 }
24179 }
24182 else
24185 }
24187 /* Returns true if ARGS (a collection of template arguments) contains
24188 any types that require structural equality testing. */
24190 bool
24192 {
24202 {
24205 {
24211 {
24212 /* Look inside the argument pack. */
24215 }
24218 {
24231 }
24232 }
24233 }
24236 }
24238 /* Returns true if ARGS (a collection of template arguments) contains
24239 any dependent arguments. */
24241 bool
24243 {
24253 {
24258 }
24261 }
24263 /* Returns TRUE if the template TMPL is type-dependent. */
24265 bool
24267 {
24269 {
24271 {
24275 }
24277 }
24279 /* Template template parameters are dependent. */
24283 /* So are names that have not been looked up. */
24287 }
24289 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24291 bool
24293 {
24296 }
24298 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24299 are dependent. */
24301 bool
24303 {
24310 {
24332 {
24336 }
24340 {
24344 {
24349 }
24350 }
24351 }
24354 }
24356 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24357 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24358 no such TYPE can be found. Note that this function peers inside
24359 uninstantiated templates and therefore should be used only in
24360 extremely limited situations. ONLY_CURRENT_P restricts this
24361 peering to the currently open classes hierarchy (which is required
24362 when comparing types). */
24364 tree
24366 {
24367 tree scope;
24368 tree name;
24369 tree decl;
24371 tree pushed_scope;
24372 tree result;
24377 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24378 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24379 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24380 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24381 identifier of the TYPENAME_TYPE anymore.
24382 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24383 TYPENAME_TYPE instead, we avoid messing up with a possible
24384 typedef variant case. */
24387 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24388 it first before we can figure out what NAME refers to. */
24390 {
24392 /* Given a class template A with a dependent base with nested type C,
24393 typedef typename A::C::C C will land us here, as trying to resolve
24394 the initial A::C leads to the local C typedef, which leads back to
24395 A::C::C. So we break the recursion now. */
24397 else
24399 }
24400 /* If we don't know what SCOPE refers to, then we cannot resolve the
24401 TYPENAME_TYPE. */
24404 /* If this is a typedef, we don't want to look inside (c++/11987). */
24407 /* If SCOPE isn't the template itself, it will not have a valid
24408 TYPE_FIELDS list. */
24410 /* scope is either the template itself or a compatible instantiation
24411 like X<T>, so look up the name in the original template. */
24413 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24415 /* If scope has no fields, it can't be a current instantiation. Check this
24416 before currently_open_class to avoid infinite recursion (71515). */
24419 /* If the SCOPE is not the current instantiation, there's no reason
24420 to look inside it. */
24423 /* Enter the SCOPE so that name lookup will be resolved as if we
24424 were in the class definition. In particular, SCOPE will no
24425 longer be considered a dependent type. */
24427 /* Look up the declaration. */
24429 tf_warning_or_error);
24433 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24434 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24439 {
24443 }
24446 {
24447 tree tmpl;
24448 tree args;
24449 /* Obtain the template and the arguments. */
24452 /* Instantiate the template. */
24458 }
24460 /* Leave the SCOPE. */
24464 /* If we failed to resolve it, return the original typename. */
24468 /* If lookup found a typename type, resolve that too. */
24470 {
24471 /* Ill-formed programs can cause infinite recursion here, so we
24472 must catch that. */
24476 }
24478 /* Qualify the resulting type. */
24484 }
24486 /* EXPR is an expression which is not type-dependent. Return a proxy
24487 for EXPR that can be used to compute the types of larger
24488 expressions containing EXPR. */
24490 tree
24492 {
24493 tree inner_expr;
24495 /* When checking, try to get a constant value for all non-dependent
24496 expressions in order to expose bugs in *_dependent_expression_p
24497 and constexpr. This can affect code generation, see PR70704, so
24498 only do this for -fchecking=2. */
24501 /* Don't do this during nsdmi parsing as it can lead to
24502 unexpected recursive instantiations. */
24504 /* Don't do this during concept expansion either and for
24505 the same reason. */
24509 /* Preserve OVERLOADs; the functions must be available to resolve
24510 types. */
24521 /* There is no need to return a proxy for a variable. */
24524 /* Preserve string constants; conversions from string constants to
24525 "char *" are allowed, even though normally a "const char *"
24526 cannot be used to initialize a "char *". */
24529 /* Preserve void and arithmetic constants, as an optimization -- there is no
24530 reason to create a new node. */
24535 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
24536 There is at least one place where we want to know that a
24537 particular expression is a throw-expression: when checking a ?:
24538 expression, there are special rules if the second or third
24539 argument is a throw-expression. */
24543 /* Don't wrap an initializer list, we need to be able to look inside. */
24547 /* Don't wrap a dummy object, we need to be able to test for it. */
24566 /* If the type is unknown, it can't really be non-dependent */
24569 /* Otherwise, build a NON_DEPENDENT_EXPR. */
24571 }
24573 /* ARGS is a vector of expressions as arguments to a function call.
24574 Replace the arguments with equivalent non-dependent expressions.
24575 This modifies ARGS in place. */
24577 void
24579 {
24581 tree arg;
24584 {
24588 }
24589 }
24591 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
24592 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
24593 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
24595 static tree
24597 {
24611 }
24613 tree
24615 {
24617 }
24619 tree
24621 {
24623 }
24625 /* Return a C++17 deduction placeholder for class template TMPL. */
24627 tree
24629 {
24633 }
24635 /* Make a "constrained auto" type-specifier. This is an
24636 auto type with constraints that must be associated after
24637 deduction. The constraint is formed from the given
24638 CONC and its optional sequence of arguments, which are
24639 non-null if written as partial-concept-id. */
24641 tree
24643 {
24646 /* Build the constraint. */
24648 tree expr;
24651 else
24657 /* Our canonical type depends on the constraint. */
24660 /* Attach the constraint to the type declaration. */
24663 }
24665 /* Given type ARG, return std::initializer_list<ARG>. */
24667 static tree
24669 {
24670 tree std_init_list = namespace_binding
24672 tree argvec;
24674 {
24678 }
24683 }
24685 /* Replace auto in TYPE with std::initializer_list<auto>. */
24687 static tree
24689 {
24696 }
24698 /* Hash traits for hashing possibly constrained 'auto'
24699 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
24702 {
24705 };
24707 /* Hash the 'auto' T. */
24709 inline hashval_t
24711 {
24713 /* Matching constrained-type-specifiers denote the same template
24714 parameter, so hash the constraint. */
24716 else
24717 /* But unconstrained autos are all separate, so just hash the pointer. */
24719 }
24721 /* Compare two 'auto's. */
24725 {
24732 /* Two unconstrained autos are distinct. */
24737 }
24739 /* for_each_template_parm callback for extract_autos: if t is a (possibly
24740 constrained) auto, add it to the vector. */
24742 static int
24744 {
24747 {
24748 /* All the autos were built with index 0; fix that up now. */
24752 /* If this is a repeated constrained-type-specifier, use the index we
24753 chose before. */
24755 else
24756 {
24757 /* Otherwise this is new, so use the current count. */
24760 }
24762 }
24764 /* Always keep walking. */
24766 }
24768 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
24769 says they can appear anywhere in the type. */
24771 static tree
24773 {
24782 {
24787 }
24790 }
24792 /* The stem for deduction guide names. */
24795 /* Return the name for a deduction guide for class template TMPL. */
24797 tree
24799 {
24810 }
24812 /* True if NAME is the name of a deduction guide. */
24814 bool
24816 {
24820 }
24822 /* True if FN is a deduction guide. */
24824 bool
24826 {
24831 }
24833 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
24834 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
24835 template parameter types. Note that the handling of template template
24836 parameters relies on current_template_parms being set appropriately for the
24837 new template. */
24839 static tree
24842 {
24845 tree newtype;
24848 {
24855 }
24856 else
24860 tree newdecl
24865 tree newidx;
24868 {
24876 {
24881 // First create a copy (ttargs) of tsubst_args with an
24882 // additional level for the template template parameter's own
24883 // template parameters (ttparms).
24884 tree ttparms = (INNERMOST_TEMPLATE_PARMS
24892 // Substitute ttargs into ttparms to fix references to
24893 // other template parameters.
24895 complain);
24896 // Now substitute again with args based on tparms, to reduce
24897 // the level of the ttparms.
24900 complain);
24901 // Finally, tack the adjusted parms onto tparms.
24903 current_template_parms);
24905 }
24906 }
24907 else
24908 {
24910 tree newconst
24920 }
24925 }
24927 /* Returns a C++17 class deduction guide template based on the constructor
24928 CTOR. */
24930 static tree
24932 {
24936 tree fn_tmpl;
24938 {
24941 }
24942 else
24946 /* If type is a member class template, DECL_TI_ARGS (ctor) will have fully
24947 specialized args for the enclosing class. Strip those off, as the
24948 deduction guide won't have those template parameters. */
24951 /* Discard the 'this' parameter. */
24957 {
24958 /* For a member template constructor, we need to flatten the two template
24959 parameter lists into one, and then adjust the function signature
24960 accordingly. This gets...complicated. */
24964 /* For a member template we should have two levels of parms/args, one for
24965 the class and one for the constructor. We stripped specialized args
24966 for further enclosing classes above. */
24970 /* Template args for translating references to the two-level template
24971 parameters into references to the one-level template parameters we are
24972 creating. */
24977 /* Template parms for the constructor template. */
24980 /* Template parms for the class template. */
24984 /* Template parms for the deduction guide start as a copy of the template
24985 parms for the class. We set current_template_parms for
24986 lookup_template_class_1. */
24992 /* Now we need to rewrite the constructor parms to append them to the
24993 class parms. */
24995 {
25010 }
25012 /* Now we have a final set of template parms to substitute into the
25013 function signature. */
25023 }
25024 else
25025 {
25026 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25030 }
25034 FUNCTION_DECL,
25049 }
25051 /* Deduce template arguments for the class template placeholder PTYPE for
25052 template TMPL based on the initializer INIT, and return the resulting
25053 type. */
25055 static tree
25057 tsubst_flags_t complain)
25058 {
25060 {
25061 /* We should have handled this in the caller. */
25067 }
25076 else
25080 {
25081 /* First try to deduce directly, since we don't have implicitly-declared
25082 constructors yet. */
25091 }
25103 {
25106 }
25109 // FIXME cache artificial deduction guides
25111 {
25115 }
25118 {
25122 }
25124 /* Prune explicit deduction guides in copy-initialization context. */
25127 {
25133 {
25136 {
25140 }
25143 {
25145 " of %qT, as it has no non-explicit deduction guides or "
25148 }
25149 }
25150 }
25154 tf_decltype);
25157 {
25164 }
25170 }
25172 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25173 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25175 tree
25177 {
25179 tf_warning_or_error,
25180 adc_unspecified);
25181 }
25183 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25184 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25185 The CONTEXT determines the context in which auto deduction is performed
25186 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25187 OUTER_TARGS are used during template argument deduction
25188 (context == adc_unify) to properly substitute the result, and is ignored
25189 in other contexts.
25191 For partial-concept-ids, extra args may be appended to the list of deduced
25192 template arguments prior to determining constraint satisfaction. */
25194 tree
25198 {
25199 tree targs;
25206 /* Defining a subset of type-dependent expressions that we can deduce
25207 from ahead of time isn't worth the trouble. */
25211 /* C++17 class template argument deduction. */
25215 /* Nothing we can do with this, even in deduction context. */
25218 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25219 with either a new invented type template parameter U or, if the
25220 initializer is a braced-init-list (8.5.4), with
25221 std::initializer_list<U>. */
25223 {
25228 else
25229 {
25231 {
25235 "for deduction to %<std::initializer_list%>, use copy-"
25237 }
25239 }
25240 }
25251 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25252 and initializer has array type, deduce cv-qualified array type. */
25254 complain);
25256 {
25265 {
25269 }
25270 }
25271 else
25272 {
25274 tree tparms;
25278 else
25279 {
25283 }
25290 {
25292 /* Try again at instantiation time. */
25296 /* If type is error_mark_node a diagnostic must have been
25297 emitted by now. Also, having a mention to '<type error>'
25298 in the diagnostic is not really useful to the user. */
25299 {
25303 else
25308 }
25310 }
25311 }
25313 /* Check any placeholder constraints against the deduced type. */
25316 {
25317 /* Use the deduced type to check the associated constraints. If we
25318 have a partial-concept-id, rebuild the argument list so that
25319 we check using the extra arguments. */
25323 {
25326 }
25327 else
25330 {
25332 {
25334 {
25352 }
25354 }
25356 }
25357 }
25363 }
25365 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
25366 result. */
25368 tree
25370 {
25372 {
25378 /* In an abbreviated function template we didn't know we were dealing
25379 with a function template when we saw the auto return type, so update
25380 it to have the correct level. */
25382 }
25384 }
25386 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
25387 'decltype(auto)' or a deduced class template. */
25389 bool
25391 {
25397 else
25399 }
25401 /* for_each_template_parm callback for type_uses_auto. */
25403 int
25405 {
25407 }
25409 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
25410 a use of `auto'. Returns NULL_TREE otherwise. */
25412 tree
25414 {
25418 {
25419 /* The Concepts TS allows multiple autos in one type-specifier; just
25420 return the first one we find, do_auto_deduction will collect all of
25421 them. */
25425 else
25427 }
25428 else
25430 }
25432 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
25433 'decltype(auto)' or a concept. */
25435 bool
25437 {
25439 }
25441 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
25442 a concept identifier) iff TYPE contains a use of a generic type. Returns
25443 NULL_TREE otherwise. */
25445 tree
25447 {
25449 }
25452 /* For a given template T, return the vector of typedefs referenced
25453 in T for which access check is needed at T instantiation time.
25454 T is either a FUNCTION_DECL or a RECORD_TYPE.
25455 Those typedefs were added to T by the function
25456 append_type_to_template_for_access_check. */
25460 {
25461 tree ti;
25472 {
25477 }
25480 }
25482 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
25483 tied to T. That list of typedefs will be access checked at
25484 T instantiation time.
25485 T is either a FUNCTION_DECL or a RECORD_TYPE.
25486 TYPE_DECL is a TYPE_DECL node representing a typedef.
25487 SCOPE is the scope through which TYPE_DECL is accessed.
25488 LOCATION is the location of the usage point of TYPE_DECL.
25490 This function is a subroutine of
25491 append_type_to_template_for_access_check. */
25493 static void
25495 tree type_decl,
25496 tree scope,
25497 location_t location)
25498 {
25499 qualified_typedef_usage_t typedef_usage;
25500 tree ti;
25507 && type_decl
25521 }
25523 /* Append TYPE_DECL to the template TEMPL.
25524 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
25525 At TEMPL instanciation time, TYPE_DECL will be checked to see
25526 if it can be accessed through SCOPE.
25527 LOCATION is the location of the usage point of TYPE_DECL.
25529 e.g. consider the following code snippet:
25531 class C
25532 {
25533 typedef int myint;
25534 };
25536 template<class U> struct S
25537 {
25538 C::myint mi; // <-- usage point of the typedef C::myint
25539 };
25541 S<char> s;
25543 At S<char> instantiation time, we need to check the access of C::myint
25544 In other words, we need to check the access of the myint typedef through
25545 the C scope. For that purpose, this function will add the myint typedef
25546 and the scope C through which its being accessed to a list of typedefs
25547 tied to the template S. That list will be walked at template instantiation
25548 time and access check performed on each typedefs it contains.
25549 Note that this particular code snippet should yield an error because
25550 myint is private to C. */
25552 void
25554 tree type_decl,
25555 tree scope,
25556 location_t location)
25557 {
25563 /* Make sure we don't append the type to the template twice. */
25570 }
25572 /* Convert the generic type parameters in PARM that match the types given in the
25573 range [START_IDX, END_IDX) from the current_template_parms into generic type
25574 packs. */
25576 tree
25578 {
25589 {
25590 /* Create a distinct parameter pack type from the current parm and add it
25591 to the replacement args to tsubst below into the generic function
25592 parameter. */
25607 }
25613 /* If there are more levels then build up the replacement with the outer
25614 template parms. */
25618 replacement);
25621 }
25623 /* Entries in the decl_constraint hash table. */
25625 {
25626 tree decl;
25627 tree ci;
25628 };
25630 /* Hashing function and equality for constraint entries. */
25632 {
25634 {
25636 }
25639 {
25641 }
25642 };
25644 /* A mapping from declarations to constraint information. Note that
25645 both templates and their underlying declarations are mapped to the
25646 same constraint information.
25648 FIXME: This is defined in pt.c because garbage collection
25649 code is not being generated for constraint.cc. */
25653 /* Returns the template constraints of declaration T. If T is not
25654 constrained, return NULL_TREE. Note that T must be non-null. */
25656 tree
25658 {
25669 else
25671 }
25673 /* Associate the given constraint information CI with the declaration
25674 T. If T is a template, then the constraints are associated with
25675 its underlying declaration. Don't build associations if CI is
25676 NULL_TREE. */
25678 void
25680 {
25692 }
25694 /* Remove the associated constraints of the declaration T. */
25696 void
25698 {
25707 }
25709 /* Memoized satisfaction results for declarations. This
25710 maps the pair (constraint_info, arguments) to the result computed
25711 by constraints_satisfied_p. */
25714 {
25715 tree ci;
25716 tree args;
25717 tree result;
25718 };
25720 /* Hashing function and equality for constraint entries. */
25723 {
25725 {
25728 }
25731 {
25733 }
25734 };
25736 /* Memoized satisfaction results for concept checks. */
25739 {
25740 tree tmpl;
25741 tree args;
25742 tree result;
25743 };
25745 /* Hashing function and equality for constraint entries. */
25748 {
25750 {
25752 }
25755 {
25760 }
25761 };
25766 /* Search for a memoized satisfaction result. Returns one of the
25767 truth value nodes if previously memoized, or NULL_TREE otherwise. */
25769 tree
25771 {
25776 else
25778 }
25780 /* Memoize the result of a satisfication test. Returns the saved result. */
25782 tree
25784 {
25791 }
25793 /* Search for a memoized satisfaction result for a concept. */
25795 tree
25797 {
25802 else
25804 }
25806 /* Memoize the result of a concept check. Returns the saved result. */
25808 tree
25810 {
25817 }
25821 /* Returns a prior concept specialization. This returns the substituted
25822 and normalized constraints defined by the concept. */
25824 tree
25826 {
25831 else
25833 }
25835 /* Save a concept expansion for later. */
25837 tree
25839 {
25846 }
25848 static hashval_t
25850 {
25859 }
25861 /* Compare the constraints of two subsumption entries. The LEFT1 and
25862 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
25863 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
25865 static bool
25867 {
25875 }
25877 /* Key/value pair for learning and memoizing subsumption results. This
25878 associates a pair of check constraints (including arguments) with
25879 a boolean value indicating the result. */
25882 {
25883 tree t1;
25884 tree t2;
25886 };
25888 /* Hashing function and equality for constraint entries. */
25891 {
25893 {
25895 }
25898 {
25903 }
25904 };
25908 /* Search for a previously cached subsumption result. */
25912 {
25917 else
25919 }
25921 /* Save a subsumption result. */
25923 bool
25925 {
25932 }
25934 /* Set up the hash table for constraint association. */
25936 void
25938 {
25947 }
25949 /* Set up the hash tables for template instantiations. */
25951 void
25953 {
25956 }
25958 /* Print stats about the template hash tables for -fstats. */
25960 void
25962 {
25971 }