| blob | 6072432382d51afa304f7a791e57e5cd2098f761 |
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. */
3609 {
3610 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3611 type_pack_expansion_p to false so that any placeholders
3612 within the expression don't get marked as parameter packs. */
3620 }
3624 }
3627 }
3629 /* Determines if the expression or type T uses any parameter packs. */
3630 bool
3632 {
3641 }
3643 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3644 representation a base-class initializer into a parameter pack
3645 expansion. If all goes well, the resulting node will be an
3646 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3647 respectively. */
3648 tree
3650 {
3651 tree result;
3660 {
3661 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3662 class initializer. In this case, the TREE_PURPOSE will be a
3663 _TYPE node (representing the base class expansion we're
3664 initializing) and the TREE_VALUE will be a TREE_LIST
3665 containing the initialization arguments.
3667 The resulting expansion looks somewhat different from most
3668 expansions. Rather than returning just one _EXPANSION, we
3669 return a TREE_LIST whose TREE_PURPOSE is a
3670 TYPE_PACK_EXPANSION containing the bases that will be
3671 initialized. The TREE_VALUE will be identical to the
3672 original TREE_VALUE, which is a list of arguments that will
3673 be passed to each base. We do not introduce any new pack
3674 expansion nodes into the TREE_VALUE (although it is possible
3675 that some already exist), because the TREE_PURPOSE and
3676 TREE_VALUE all need to be expanded together with the same
3677 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3678 resulting TREE_PURPOSE will mention the parameter packs in
3679 both the bases and the arguments to the bases. */
3680 tree purpose;
3681 tree value;
3684 /* Determine which parameter packs will be used by the base
3685 class expansion. */
3694 {
3698 }
3701 {
3702 /* Collect the sets of parameter packs used in each of the
3703 initialization arguments. */
3705 {
3706 /* Determine which parameter packs will be expanded in this
3707 argument. */
3710 }
3711 }
3715 /* Create the pack expansion type for the base type. */
3720 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3721 they will rarely be compared to anything. */
3725 }
3730 /* Build the PACK_EXPANSION_* node. */
3731 result = for_types
3736 {
3737 /* Propagate type and const-expression information. */
3740 /* Mark this read now, since the expansion might be length 0. */
3742 }
3743 else
3744 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3745 they will rarely be compared to anything. */
3748 /* Determine which parameter packs will be expanded. */
3755 /* Make sure we found some parameter packs. */
3757 {
3760 else
3763 }
3769 }
3771 /* Checks T for any "bare" parameter packs, which have not yet been
3772 expanded, and issues an error if any are found. This operation can
3773 only be done on full expressions or types (e.g., an expression
3774 statement, "if" condition, etc.), because we could have expressions like:
3776 foo(f(g(h(args)))...)
3778 where "args" is a parameter pack. check_for_bare_parameter_packs
3779 should not be called for the subexpressions args, h(args),
3780 g(h(args)), or f(g(h(args))), because we would produce erroneous
3781 error messages.
3783 Returns TRUE and emits an error if there were bare parameter packs,
3784 returns FALSE otherwise. */
3785 bool
3787 {
3804 {
3808 {
3817 else
3822 else
3826 }
3829 }
3832 }
3834 /* Expand any parameter packs that occur in the template arguments in
3835 ARGS. */
3836 tree
3838 {
3847 /* First, determine if we need to expand anything, and the number of
3848 slots we'll need. */
3850 {
3855 {
3859 else
3861 }
3862 else
3863 {
3865 num_result_args++;
3866 }
3867 }
3869 /* If no expansion is necessary, we're done. */
3873 /* Expand arguments. */
3876 non_default_args_count =
3879 {
3882 {
3889 }
3890 else
3891 {
3894 }
3895 }
3899 }
3901 /* Checks if DECL shadows a template parameter.
3903 [temp.local]: A template-parameter shall not be redeclared within its
3904 scope (including nested scopes).
3906 Emits an error and returns TRUE if the DECL shadows a parameter,
3907 returns FALSE otherwise. */
3909 bool
3911 {
3912 tree olddecl;
3914 /* If we're not in a template, we can't possibly shadow a template
3915 parameter. */
3919 /* Figure out what we're shadowing. */
3924 /* If there's no previous binding for this name, we're not shadowing
3925 anything, let alone a template parameter. */
3929 /* If we're not shadowing a template parameter, we're done. Note
3930 that OLDDECL might be an OVERLOAD (or perhaps even an
3931 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3932 node. */
3936 /* We check for decl != olddecl to avoid bogus errors for using a
3937 name inside a class. We check TPFI to avoid duplicate errors for
3938 inline member templates. */
3944 /* Don't complain about the injected class name, as we've already
3945 complained about the class itself. */
3952 else
3957 }
3959 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3960 ORIG_LEVEL, DECL, and TYPE. */
3962 static tree
3966 tree decl,
3967 tree type)
3968 {
3979 }
3981 /* Find the canonical type parameter for the given template type
3982 parameter. Returns the canonical type parameter, which may be TYPE
3983 if no such parameter existed. */
3985 static tree
3987 {
3988 tree list;
4002 else
4003 {
4008 }
4009 }
4011 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4012 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4013 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4014 new one is created. */
4016 static tree
4018 tsubst_flags_t complain)
4019 {
4024 {
4043 /* Template template parameters need this. */
4045 {
4052 }
4053 }
4056 }
4058 /* Process information from new template parameter PARM and append it
4059 to the LIST being built. This new parameter is a non-type
4060 parameter iff IS_NON_TYPE is true. This new parameter is a
4061 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4062 is in PARM_LOC. */
4064 tree
4067 {
4076 {
4080 {
4084 else
4086 }
4089 }
4092 {
4098 {
4099 /* [temp.param]
4101 The top-level cv-qualifiers on the template-parameter are
4102 ignored when determining its type. */
4107 && !is_parameter_pack
4108 /* If we're in a nested template parameter list, the template
4109 template parameter could be a parameter pack. */
4111 {
4112 /* This template parameter is not a parameter pack, but it
4113 should be. Complain about "bare" parameter packs. */
4116 /* Recover by calling this a parameter pack. */
4118 }
4119 }
4121 /* A template parameter is not modifiable. */
4130 processing_template_decl,
4135 }
4136 else
4137 {
4138 tree t;
4142 {
4144 /* This is for distinguishing between real templates and template
4145 template parameters */
4149 }
4150 else
4151 {
4153 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4156 }
4163 processing_template_decl,
4167 }
4171 /* Build requirements for the type/template parameter.
4172 This must be done after SET_DECL_TEMPLATE_PARM_P or
4173 process_template_parm could fail. */
4178 /* Build the parameter node linking the parameter declaration,
4179 its default argument (if any), and its constraints (if any). */
4184 }
4186 /* The end of a template parameter list has been reached. Process the
4187 tree list into a parameter vector, converting each parameter into a more
4188 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4189 as PARM_DECLs. */
4191 tree
4193 {
4198 /* Pop the dummy parameter level and add the real one. */
4201 current_template_parms
4206 {
4210 }
4215 }
4217 // Explicitly indicate the end of the template parameter list. We assume
4218 // that the current template parameters have been constructed and/or
4219 // managed explicitly, as when creating new template template parameters
4220 // from a shorthand constraint.
4221 void
4223 {
4225 }
4227 /* end_template_decl is called after a template declaration is seen. */
4229 void
4231 {
4237 /* This matches the pushlevel in begin_template_parm_list. */
4242 }
4244 /* Takes a TREE_LIST representing a template parameter and convert it
4245 into an argument suitable to be passed to the type substitution
4246 functions. Note that If the TREE_LIST contains an error_mark
4247 node, the returned argument is error_mark_node. */
4249 tree
4251 {
4264 {
4268 {
4269 /* Turn this argument into a TYPE_ARGUMENT_PACK
4270 with a single element, which expands T. */
4279 }
4280 }
4281 else
4282 {
4286 {
4287 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4288 with a single element, which expands T. */
4300 }
4301 else
4303 }
4305 }
4307 /* Given a single level of template parameters (a TREE_VEC), return it
4308 as a set of template arguments. */
4310 static tree
4312 {
4322 }
4324 /* Given a set of template parameters, return them as a set of template
4325 arguments. The template parameters are represented as a TREE_VEC, in
4326 the form documented in cp-tree.h for template arguments. */
4328 static tree
4330 {
4331 tree header;
4336 /* If there is only one level of template parameters, we do not
4337 create a TREE_VEC of TREE_VECs. Instead, we return a single
4338 TREE_VEC containing the arguments. */
4343 {
4348 else
4350 }
4353 }
4355 /* Within the declaration of a template, return the currently active
4356 template parameters as an argument TREE_VEC. */
4358 static tree
4360 {
4362 }
4364 /* Update the declared TYPE by doing any lookups which were thought to be
4365 dependent, but are not now that we know the SCOPE of the declarator. */
4367 tree
4369 {
4380 /* Don't bother building up the args in this case. */
4382 {
4383 /* tsubst in the args corresponding to the template parameters,
4384 including auto if present. Most things will be unchanged, but
4385 make_typename_type and tsubst_qualified_id will resolve
4386 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4389 tree pushed;
4391 {
4395 }
4400 }
4406 {
4409 else
4411 }
4413 }
4415 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4416 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4417 the new template is a member template. */
4419 tree
4421 {
4429 }
4431 struct template_parm_data
4432 {
4433 /* The level of the template parameters we are currently
4434 processing. */
4437 /* The index of the specialization argument we are currently
4438 processing. */
4441 /* An array whose size is the number of template parameters. The
4442 elements are nonzero if the parameter has been used in any one
4443 of the arguments processed so far. */
4446 /* An array whose size is the number of template arguments. The
4447 elements are nonzero if the argument makes use of template
4448 parameters of this level. */
4450 };
4452 /* Subroutine of push_template_decl used to see if each template
4453 parameter in a partial specialization is used in the explicit
4454 argument list. If T is of the LEVEL given in DATA (which is
4455 treated as a template_parm_data*), then DATA->PARMS is marked
4456 appropriately. */
4458 static int
4460 {
4468 {
4471 }
4473 /* In C++17 the type of a non-type argument is a deduced context. */
4478 data,
4479 NULL,
4482 /* Return zero so that for_each_template_parm will continue the
4483 traversal of the tree; we want to mark *every* template parm. */
4485 }
4487 /* Process the partial specialization DECL. */
4489 static tree
4491 {
4498 tree inner_parms;
4499 tree inst;
4509 /* A concept cannot be specialized. */
4511 {
4514 }
4519 /* We check that each of the template parameters given in the
4520 partial specialization is used in the argument list to the
4521 specialization. For example:
4523 template <class T> struct S;
4524 template <class T> struct S<T*>;
4526 The second declaration is OK because `T*' uses the template
4527 parameter T, whereas
4529 template <class T> struct S<int>;
4531 is no good. Even trickier is:
4533 template <class T>
4534 struct S1
4535 {
4536 template <class U>
4537 struct S2;
4538 template <class U>
4539 struct S2<T>;
4540 };
4542 The S2<T> declaration is actually invalid; it is a
4543 full-specialization. Of course,
4545 template <class U>
4546 struct S2<T (*)(U)>;
4548 or some such would have been OK. */
4556 {
4561 NULL,
4563 }
4566 {
4567 /* One of the template parms was not used in a deduced context in the
4568 specialization. */
4570 {
4574 }
4578 }
4583 /* [temp.class.spec]
4585 The argument list of the specialization shall not be identical to
4586 the implicit argument list of the primary template. */
4587 tree main_args
4590 && (!flag_concepts
4593 {
4597 else
4601 }
4603 /* A partial specialization that replaces multiple parameters of the
4604 primary template with a pack expansion is less specialized for those
4605 parameters. */
4607 {
4609 "primary template because it replaces multiple parameters "
4612 /* Avoid crash in process_partial_specialization. */
4614 }
4616 /* If we aren't in a dependent class, we can actually try deduction. */
4619 {
4623 maintmpl);
4624 }
4626 /* [temp.class.spec]
4628 A partially specialized non-type argument expression shall not
4629 involve template parameters of the partial specialization except
4630 when the argument expression is a simple identifier.
4632 The type of a template parameter corresponding to a specialized
4633 non-type argument shall not be dependent on a parameter of the
4634 specialization.
4636 Also, we verify that pack expansions only occur at the
4637 end of the argument list. */
4641 {
4648 {
4649 /* Extract the arguments from the argument pack. We'll be
4650 iterating over these in the following loop. */
4653 }
4656 {
4658 /* Get the Jth argument in the parameter pack. */
4662 {
4663 /* Pack expansions must come at the end of the
4664 argument list. */
4667 {
4671 else
4674 }
4675 }
4678 /* We only care about the pattern. */
4684 /* This next two lines are the `argument expression is not just a
4685 simple identifier' condition and also the `specialized
4686 non-type argument' bit. */
4690 {
4694 arg);
4695 else
4696 {
4697 /* Look at the corresponding template parameter,
4698 marking which template parameters its type depends
4699 upon. */
4703 {
4704 /* We haven't yet initialized TPD2. Do so now. */
4706 /* The number of parameters here is the number in the
4707 main template, which, as checked in the assertion
4708 above, is NARGS. */
4712 }
4714 /* Mark the template parameters. But this time, we're
4715 looking for the template parameters of the main
4716 template, not in the specialization. */
4723 NULL,
4727 {
4728 /* The type depended on some template parameters.
4729 If they are fully specialized in the
4730 specialization, that's OK. */
4739 "type %qT of template argument %qE depends "
4741 "type %qT of template argument %qE depends "
4743 type,
4744 arg);
4745 }
4746 }
4747 }
4748 }
4749 }
4751 /* We should only get here once. */
4755 // Build the template decl.
4764 /* Give template template parms a DECL_CONTEXT of the template
4765 for which they are a parameter. */
4767 {
4771 }
4774 /* We didn't register this in check_explicit_specialization so we could
4775 wait until the constraints were set. */
4777 else
4787 {
4793 {
4801 "declaration of %qD ambiguates earlier template "
4805 "partial specialization of %qD after instantiation "
4807 }
4808 }
4811 }
4813 /* PARM is a template parameter of some form; return the corresponding
4814 TEMPLATE_PARM_INDEX. */
4816 static tree
4818 {
4831 }
4833 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4834 parameter packs used by the template parameter PARM. */
4836 static void
4838 {
4839 /* A type parm can't refer to another parm. */
4843 {
4847 }
4854 }
4856 /* PARM is a template parameter pack. Return any parameter packs used in
4857 its type or the type of any of its template parameters. If there are
4858 any such packs, it will be instantiated into a fixed template parameter
4859 list by partial instantiation rather than be fully deduced. */
4861 tree
4863 {
4864 /* This can only be true in a member template. */
4867 /* This can only be true for a parameter pack. */
4870 /* A type parm can't refer to another parm. */
4884 }
4886 /* Check that a template declaration's use of default arguments and
4887 parameter packs is not invalid. Here, PARMS are the template
4888 parameters. IS_PRIMARY is true if DECL is the thing declared by
4889 a primary template. IS_PARTIAL is true if DECL is a partial
4890 specialization.
4892 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4893 declaration (but not a definition); 1 indicates a declaration, 2
4894 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4895 emitted for extraneous default arguments.
4897 Returns TRUE if there were no errors found, FALSE otherwise. */
4899 bool
4902 {
4905 tree parm_level;
4908 /* [temp.param]
4910 A default template-argument shall not be specified in a
4911 function template declaration or a function template definition, nor
4912 in the template-parameter-list of the definition of a member of a
4913 class template. */
4917 /* You can't have a function template declaration in a local
4918 scope, nor you can you define a member of a class template in a
4919 local scope. */
4927 /* A lambda doesn't have an explicit declaration; don't complain
4928 about the parms of the enclosing class. */
4935 /* If this is either a friend defined in the scope of the class
4936 or a member function. */
4942 /* And, if it was a member function, it really was defined in
4943 the scope of the class. */
4946 /* We already checked these parameters when the template was
4947 declared, so there's no need to do it again now. This function
4948 was defined in class scope, but we're processing its body now
4949 that the class is complete. */
4952 /* Core issue 226 (C++0x only): the following only applies to class
4953 templates. */
4956 {
4957 /* [temp.param]
4959 If a template-parameter has a default template-argument, all
4960 subsequent template-parameters shall have a default
4961 template-argument supplied. */
4963 {
4970 {
4980 {
4982 /* For better subsequent error-recovery, we indicate that
4983 there should have been a default argument. */
4986 }
4988 && !is_friend_decl
4989 /* Don't complain about an enclosing partial
4990 specialization. */
4995 /* A fixed parameter pack will be partially
4996 instantiated into a fixed length list. */
4998 {
4999 /* A primary class template can only have one
5000 parameter pack, at the end of the template
5001 parameter list. */
5009 }
5010 }
5011 }
5012 }
5015 || is_partial
5016 || !is_primary
5018 /* For an ordinary class template, default template arguments are
5019 allowed at the innermost level, e.g.:
5020 template <class T = int>
5021 struct S {};
5022 but, in a partial specialization, they're not allowed even
5023 there, as we have in [temp.class.spec]:
5025 The template parameter list of a specialization shall not
5026 contain default template argument values.
5028 So, for a partial specialization, or for a function template
5029 (in C++98/C++03), we look at all of them. */
5030 ;
5031 else
5032 /* But, for a primary class template that is not a partial
5033 specialization we look at all template parameters except the
5034 innermost ones. */
5037 /* Figure out what error message to issue. */
5052 else
5053 /* Per [temp.param]/9, "A default template-argument shall not be
5054 specified in the template-parameter-lists of the definition of
5055 a member of a class template that appears outside of the member's
5056 class.", thus if we aren't handling a member of a class template
5057 there is no need to examine the parameters. */
5061 /* If we're inside a class definition, there's no need to
5062 examine the parameters to the class itself. On the one
5063 hand, they will be checked when the class is defined, and,
5064 on the other, default arguments are valid in things like:
5065 template <class T = double>
5066 struct S { template <class U> void f(U); };
5067 Here the default argument for `S' has no bearing on the
5068 declaration of `f'. */
5070 else
5071 /* Check everything. */
5077 {
5084 {
5089 {
5091 {
5098 }
5100 /* Clear out the default argument so that we are not
5101 confused later. */
5103 }
5104 }
5106 /* At this point, if we're still interested in issuing messages,
5107 they must apply to classes surrounding the object declared. */
5111 }
5114 }
5116 /* Worker for push_template_decl_real, called via
5117 for_each_template_parm. DATA is really an int, indicating the
5118 level of the parameters we are interested in. If T is a template
5119 parameter of that level, return nonzero. */
5121 static int
5123 {
5129 else
5132 }
5134 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5135 DATA is really an int, indicating the innermost outer level of parameters.
5136 If T is a template parameter of that level or further out, return
5137 nonzero. */
5139 static int
5141 {
5147 else
5150 }
5152 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5153 parameters given by current_template_args, or reuses a
5154 previously existing one, if appropriate. Returns the DECL, or an
5155 equivalent one, if it is replaced via a call to duplicate_decls.
5157 If IS_FRIEND is true, DECL is a friend declaration. */
5159 tree
5161 {
5162 tree tmpl;
5163 tree args;
5164 tree info;
5165 tree ctx;
5169 /* True if the template is a member template, in the sense of
5170 [temp.mem]. */
5176 /* See if this is a partial specialization. */
5189 /* For a friend, we want the context of the friend function, not
5190 the type of which it is a friend. */
5194 /* In the case of a virtual function, we want the class in which
5195 it is defined. */
5197 else
5198 /* Otherwise, if we're currently defining some class, the DECL
5199 is assumed to be a member of the class. */
5208 /* See if this is a primary template. */
5211 /* A friend template that specifies a class context, i.e.
5212 template <typename T> friend void A<T>::f();
5213 is not primary. */
5218 else
5222 {
5229 {
5232 }
5234 {
5236 {
5239 }
5241 {
5242 /* [temp.mem]
5244 A destructor shall not be a member template. */
5247 }
5254 {
5255 /* [basic.stc.dynamic.allocation]
5257 An allocation function can be a function
5258 template. ... Template allocation functions shall
5259 have two or more parameters. */
5262 }
5263 }
5266 {
5267 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5270 {
5276 }
5277 }
5280 /* alias-declaration */
5284 else
5285 {
5288 }
5289 }
5291 /* Check to see that the rules regarding the use of default
5292 arguments are not being violated. */
5296 /* Ensure that there are no parameter packs in the type of this
5297 declaration that have not been expanded. */
5299 {
5300 /* Check each of the arguments individually to see if there are
5301 any bare parameter packs. */
5307 {
5310 {
5311 /* This is a PARM_DECL that contains unexpanded parameter
5312 packs. We have already complained about this in the
5313 check_for_bare_parameter_packs call, so just replace
5314 these types with ERROR_MARK_NODE. */
5317 }
5321 }
5323 /* Check for bare parameter packs in the return type and the
5324 exception specifiers. */
5326 /* Errors were already issued, set return type to int
5327 as the frontend doesn't expect error_mark_node as
5328 the return type. */
5332 }
5337 {
5340 }
5353 {
5358 /* If DECL is a TYPE_DECL for a class-template, then there won't
5359 be DECL_LANG_SPECIFIC. The information equivalent to
5360 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5364 {
5365 /* Since a template declaration already existed for this
5366 class-type, we must be redeclaring it here. Make sure
5367 that the redeclaration is valid. */
5369 current_template_parms,
5371 /* We don't need to create a new TEMPLATE_DECL; just use the
5372 one we already had. */
5374 }
5375 else
5376 {
5378 member_template_p);
5383 {
5384 /* A specialization of a member template of a template
5385 class. */
5389 }
5390 }
5391 }
5392 else
5393 {
5399 {
5402 }
5410 {
5411 tree new_tmpl;
5413 /* The declaration is a specialization of a member
5414 template, declared outside the class. Therefore, the
5415 innermost template arguments will be NULL, so we
5416 replace them with the arguments determined by the
5417 earlier call to check_explicit_specialization. */
5420 new_tmpl
5422 member_template_p);
5432 args,
5435 }
5437 /* Make sure the template headers we got make sense. */
5442 {
5447 }
5448 else
5450 {
5455 {
5459 else
5463 /* Avoid crash in import_export_decl. */
5466 }
5471 /* Can happen in erroneous input. */
5473 else
5475 }
5477 /* Check that the parms are used in the appropriate qualifying scopes
5478 in the declarator. */
5482 {
5488 /* Avoid crash in import_export_decl. */
5491 }
5492 }
5497 /* Push template declarations for global functions and types. Note
5498 that we do not try to push a global template friend declared in a
5499 template class; such a thing may well depend on the template
5500 parameters of the class. */
5503 {
5508 /* Hide template friend classes that haven't been declared yet. */
5510 {
5513 }
5514 }
5517 {
5523 {
5526 /* It is a conversion operator. See if the type converted to
5527 depends on innermost template operands. */
5530 depth))
5532 }
5534 /* Give template template parms a DECL_CONTEXT of the template
5535 for which they are a parameter. */
5538 {
5542 }
5548 }
5550 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5551 back to its most general template. If TMPL is a specialization,
5552 ARGS may only have the innermost set of arguments. Add the missing
5553 argument levels if necessary. */
5561 else
5562 {
5567 }
5570 && !is_friend
5573 /* Set DECL_COMDAT on template instantiations; if we force
5574 them to be emitted by explicit instantiation or -frepo,
5575 mark_needed will tell cgraph to do the right thing. */
5579 }
5581 tree
5583 {
5585 }
5587 /* FN is an inheriting constructor that inherits from the constructor
5588 template INHERITED; turn FN into a constructor template with a matching
5589 template header. */
5591 tree
5593 {
5594 tree inner_parms
5597 tree parms
5608 }
5610 /* Called when a class template TYPE is redeclared with the indicated
5611 template PARMS, e.g.:
5613 template <class T> struct S;
5614 template <class T> struct S {}; */
5616 bool
5618 {
5619 tree tmpl;
5620 tree tmpl_parms;
5624 {
5627 }
5631 /* The type is nested in some template class. Nothing to worry
5632 about here; there are no new template parameters for the nested
5633 type. */
5637 {
5639 tmpl);
5641 }
5647 {
5657 }
5660 {
5661 tree tmpl_parm;
5662 tree parm;
5663 tree tmpl_default;
5664 tree parm_default;
5678 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5679 TEMPLATE_DECL. */
5689 {
5693 }
5696 {
5697 /* We have in [temp.param]:
5699 A template-parameter may not be given default arguments
5700 by two different declarations in the same scope. */
5705 }
5708 /* Update the previous template parameters (which are the ones
5709 that will really count) with the new default value. */
5712 /* Update the new parameters, too; they'll be used as the
5713 parameters for any members. */
5716 /* Give each template template parm in this redeclaration a
5717 DECL_CONTEXT of the template for which they are a parameter. */
5719 {
5722 }
5723 }
5725 // Cannot redeclare a class template with a different set of constraints.
5727 {
5732 }
5735 }
5737 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5738 to be used when the caller has already checked
5739 (processing_template_decl
5740 && !instantiation_dependent_expression_p (expr)
5741 && potential_constant_expression (expr))
5742 and cleared processing_template_decl. */
5744 tree
5746 {
5749 complain,
5753 }
5755 /* Simplify EXPR if it is a non-dependent expression. Returns the
5756 (possibly simplified) expression. */
5758 tree
5760 {
5764 /* If we're in a template, but EXPR isn't value dependent, simplify
5765 it. We're supposed to treat:
5767 template <typename T> void f(T[1 + 1]);
5768 template <typename T> void f(T[2]);
5770 as two declarations of the same function, for example. */
5773 {
5774 processing_template_decl_sentinel s;
5776 }
5778 }
5780 tree
5782 {
5784 }
5786 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5787 an uninstantiated expression. */
5789 tree
5791 {
5795 {
5798 else
5799 {
5800 processing_template_decl_sentinel s;
5802 }
5803 }
5805 }
5807 /* True iff T is a specialization of a variable template. */
5809 bool
5811 {
5816 }
5818 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5819 template declaration, or a TYPE_DECL for an alias declaration. */
5821 bool
5823 {
5831 }
5833 /* Return TRUE iff T is a specialization of an alias template. */
5835 bool
5837 {
5838 /* It's an alias template specialization if it's an alias and its
5839 TYPE_NAME is a specialization of a primary template. */
5845 }
5847 /* An alias template is complex from a SFINAE perspective if a template-id
5848 using that alias can be ill-formed when the expansion is not, as with
5849 the void_t template. We determine this by checking whether the
5850 expansion for the alias template uses all its template parameters. */
5852 struct uses_all_template_parms_data
5853 {
5856 };
5858 static int
5860 {
5868 }
5870 static bool
5872 {
5887 }
5889 /* Return TRUE iff T is a specialization of a complex alias template with
5890 dependent template-arguments. */
5892 bool
5894 {
5907 }
5909 /* Return the number of innermost template parameters in TMPL. */
5911 static int
5913 {
5916 }
5918 /* Return either TMPL or another template that it is equivalent to under DR
5919 1286: An alias that just changes the name of a template is equivalent to
5920 the other template. */
5922 static tree
5924 {
5927 {
5928 /* Determine if the alias is equivalent to an underlying template. */
5940 tree alias_args = INNERMOST_TEMPLATE_ARGS
5945 /* Alias is equivalent. Strip it and repeat. */
5947 }
5950 }
5952 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5953 must be a reference-to-function or a pointer-to-function type, as specified
5954 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5955 and check that the resulting function has external linkage. */
5957 static tree
5959 tsubst_flags_t complain)
5960 {
5963 linkage_kind linkage;
5978 /* [temp.arg.nontype]/1
5980 A template-argument for a non-type, non-template template-parameter
5981 shall be one of:
5982 [...]
5983 -- the address of an object or function with external [C++11: or
5984 internal] linkage. */
5987 {
5989 {
5995 else
5998 }
6000 }
6004 {
6006 {
6011 else
6015 }
6017 }
6025 }
6027 /* Subroutine of convert_nontype_argument.
6028 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6029 Emit an error otherwise. */
6031 static bool
6033 tsubst_flags_t complain)
6034 {
6045 {
6049 }
6051 }
6053 /* Returns TRUE iff the address of OP is value-dependent.
6055 14.6.2.4 [temp.dep.temp]:
6056 A non-integral non-type template-argument is dependent if its type is
6057 dependent or it has either of the following forms
6058 qualified-id
6059 & qualified-id
6060 and contains a nested-name-specifier which specifies a class-name that
6061 names a dependent type.
6063 We generalize this to just say that the address of a member of a
6064 dependent class is value-dependent; the above doesn't cover the
6065 address of a static data member named with an unqualified-id. */
6067 static bool
6069 {
6070 /* We could use get_inner_reference here, but there's no need;
6071 this is only relevant for template non-type arguments, which
6072 can only be expressed as &id-expression. */
6074 {
6078 }
6081 }
6083 /* The next set of functions are used for providing helpful explanatory
6084 diagnostics for failed overload resolution. Their messages should be
6085 indented by two spaces for consistency with the messages in
6086 call.c */
6088 static int
6090 {
6092 }
6094 static int
6096 {
6101 }
6103 static int
6105 {
6107 }
6109 static int
6111 {
6117 }
6119 static int
6121 {
6125 }
6127 static int
6129 {
6132 " template parameter %qD is not a parameter pack, but "
6136 }
6138 static int
6140 {
6143 " template argument %qE does not match "
6147 }
6149 static int
6151 {
6155 }
6157 static int
6159 {
6165 }
6167 static int
6169 {
6171 {
6176 else
6178 " deduced conflicting values for non-type parameter "
6180 }
6182 }
6184 static int
6186 {
6189 " variable-sized array type %qT is not "
6191 arg);
6193 }
6195 static int
6197 {
6201 arg);
6203 }
6205 static int
6207 {
6209 {
6215 else
6220 }
6222 }
6224 static int
6226 {
6228 }
6230 static int
6233 {
6235 }
6237 static int
6240 {
6246 }
6248 static int
6251 {
6254 {
6262 }
6264 }
6266 static int
6268 {
6271 " template parameters of a template template argument are "
6274 }
6276 static int
6278 {
6284 }
6286 static int
6288 {
6293 }
6295 static int
6297 {
6301 arg);
6303 }
6305 /* Attempt to convert the non-type template parameter EXPR to the
6306 indicated TYPE. If the conversion is successful, return the
6307 converted value. If the conversion is unsuccessful, return
6308 NULL_TREE if we issued an error message, or error_mark_node if we
6309 did not. We issue error messages for out-and-out bad template
6310 parameters, but not simply because the conversion failed, since we
6311 might be just trying to do argument deduction. Both TYPE and EXPR
6312 must be non-dependent.
6314 The conversion follows the special rules described in
6315 [temp.arg.nontype], and it is much more strict than an implicit
6316 conversion.
6318 This function is called twice for each template argument (see
6319 lookup_template_class for a more accurate description of this
6320 problem). This means that we need to handle expressions which
6321 are not valid in a C++ source, but can be created from the
6322 first call (for instance, casts to perform conversions). These
6323 hacks can go away after we fix the double coercion problem. */
6325 static tree
6327 {
6328 tree expr_type;
6330 /* Detect immediately string literals as invalid non-type argument.
6331 This special-case is not needed for correctness (we would easily
6332 catch this later), but only to provide better diagnostic for this
6333 common user mistake. As suggested by DR 100, we do not mention
6334 linkage issues in the diagnostic as this is not the point. */
6335 /* FIXME we're making this OK. */
6337 {
6343 }
6345 /* Add the ADDR_EXPR now for the benefit of
6346 value_dependent_expression_p. */
6349 {
6353 }
6355 /* If we are in a template, EXPR may be non-dependent, but still
6356 have a syntactic, rather than semantic, form. For example, EXPR
6357 might be a SCOPE_REF, rather than the VAR_DECL to which the
6358 SCOPE_REF refers. Preserving the qualifying scope is necessary
6359 so that access checking can be performed when the template is
6360 instantiated -- but here we need the resolved form so that we can
6361 convert the argument. */
6374 else
6377 /* If the argument is non-dependent, perform any conversions in
6378 non-dependent context as well. */
6386 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6387 to a non-type argument of "nullptr". */
6391 /* In C++11, integral or enumeration non-type template arguments can be
6392 arbitrary constant expressions. Pointer and pointer to
6393 member arguments can be general constant expressions that evaluate
6394 to a null value, but otherwise still need to be of a specific form. */
6396 {
6398 /* A PTRMEM_CST is already constant, and a valid template
6399 argument for a parameter of pointer to member type, we just want
6400 to leave it in that form rather than lower it to a
6405 {
6409 {
6413 }
6414 }
6416 {
6421 }
6422 }
6424 /* HACK: Due to double coercion, we can get a
6425 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6426 which is the tree that we built on the first call (see
6427 below when coercing to reference to object or to reference to
6428 function). We just strip everything and get to the arg.
6429 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6430 for examples. */
6432 {
6438 {
6439 /* ??? Maybe we could use convert_from_reference here, but we
6440 would need to relax its constraints because the NOP_EXPR
6441 could actually change the type to something more cv-qualified,
6442 and this is not folded by convert_from_reference. */
6447 && (same_type_ignoring_top_level_qualifiers_p
6450 {
6453 }
6454 }
6455 }
6457 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6458 parameter is a pointer to object, through decay and
6459 qualification conversion. Let's strip everything. */
6461 {
6466 {
6467 /* Skip the ADDR_EXPR only if it is part of the decay for
6468 an array. Otherwise, it is part of the original argument
6469 in the source code. */
6474 }
6475 }
6477 /* [temp.arg.nontype]/5, bullet 1
6479 For a non-type template-parameter of integral or enumeration type,
6480 integral promotions (_conv.prom_) and integral conversions
6481 (_conv.integral_) are applied. */
6483 {
6492 /* Notice that there are constant expressions like '4 % 0' which
6493 do not fold into integer constants. */
6496 {
6498 {
6509 /* else cxx_constant_value complained but gave us
6510 a real constant, so go ahead. */
6512 }
6513 else
6515 }
6517 /* Avoid typedef problems. */
6520 }
6521 /* [temp.arg.nontype]/5, bullet 2
6523 For a non-type template-parameter of type pointer to object,
6524 qualification conversions (_conv.qual_) and the array-to-pointer
6525 conversion (_conv.array_) are applied. */
6527 {
6528 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6530 A template-argument for a non-type, non-template template-parameter
6531 shall be one of: [...]
6533 -- the name of a non-type template-parameter;
6534 -- the address of an object or function with external linkage, [...]
6535 expressed as "& id-expression" where the & is optional if the name
6536 refers to a function or array, or if the corresponding
6537 template-parameter is a reference.
6539 Here, we do not care about functions, as they are invalid anyway
6540 for a parameter of type pointer-to-object. */
6543 /* Non-type template parameters are OK. */
6544 ;
6549 {
6551 {
6554 "because %qD is a variable, not the address of "
6557 }
6559 {
6565 }
6566 /* Other values, like integer constants, might be valid
6567 non-type arguments of some other type. */
6569 }
6570 else
6571 {
6572 tree decl;
6577 {
6582 }
6584 {
6590 }
6592 {
6597 }
6598 }
6607 }
6608 /* [temp.arg.nontype]/5, bullet 3
6610 For a non-type template-parameter of type reference to object, no
6611 conversions apply. The type referred to by the reference may be more
6612 cv-qualified than the (otherwise identical) type of the
6613 template-argument. The template-parameter is bound directly to the
6614 template-argument, which must be an lvalue. */
6616 {
6618 expr_type))
6622 {
6627 }
6630 {
6635 }
6637 /* [temp.arg.nontype]/1
6639 A template-argument for a non-type, non-template template-parameter
6640 shall be one of: [...]
6642 -- the address of an object or function with external linkage. */
6645 {
6648 {
6651 "because a reference variable does not have a constant "
6654 }
6655 }
6658 {
6660 {
6666 }
6668 /* DR 1155 allows internal linkage in C++11 and up. */
6671 {
6677 }
6680 }
6681 }
6682 /* [temp.arg.nontype]/5, bullet 4
6684 For a non-type template-parameter of type pointer to function, only
6685 the function-to-pointer conversion (_conv.func_) is applied. If the
6686 template-argument represents a set of overloaded functions (or a
6687 pointer to such), the matching function is selected from the set
6688 (_over.over_). */
6690 {
6691 /* If the argument is a template-id, we might not have enough
6692 context information to decay the pointer. */
6694 {
6698 }
6701 /* Null pointer values are OK in C++11. */
6707 }
6708 /* [temp.arg.nontype]/5, bullet 5
6710 For a non-type template-parameter of type reference to function, no
6711 conversions apply. If the template-argument represents a set of
6712 overloaded functions, the matching function is selected from the set
6713 (_over.over_). */
6715 {
6717 {
6719 {
6724 }
6726 }
6731 }
6732 /* [temp.arg.nontype]/5, bullet 6
6734 For a non-type template-parameter of type pointer to member function,
6735 no conversions apply. If the template-argument represents a set of
6736 overloaded member functions, the matching member function is selected
6737 from the set (_over.over_). */
6739 {
6744 /* [temp.arg.nontype] bullet 1 says the pointer to member
6745 expression must be a pointer-to-member constant. */
6750 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6751 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6755 /* There is no way to disable standard conversions in
6756 resolve_address_of_overloaded_function (called by
6757 instantiate_type). It is possible that the call succeeded by
6758 converting &B::I to &D::I (where B is a base of D), so we need
6759 to reject this conversion here.
6761 Actually, even if there was a way to disable standard conversions,
6762 it would still be better to reject them here so that we can
6763 provide a superior diagnostic. */
6765 {
6767 {
6771 /* If we are just one standard conversion off, explain. */
6775 }
6777 }
6778 }
6779 /* [temp.arg.nontype]/5, bullet 7
6781 For a non-type template-parameter of type pointer to data member,
6782 qualification conversions (_conv.qual_) are applied. */
6784 {
6785 /* [temp.arg.nontype] bullet 1 says the pointer to member
6786 expression must be a pointer-to-member constant. */
6794 }
6796 {
6798 {
6803 }
6805 }
6806 /* A template non-type parameter must be one of the above. */
6807 else
6810 /* Sanity check: did we actually convert the argument to the
6811 right type? */
6815 }
6817 /* Subroutine of coerce_template_template_parms, which returns 1 if
6818 PARM_PARM and ARG_PARM match using the rule for the template
6819 parameters of template template parameters. Both PARM and ARG are
6820 template parameters; the rest of the arguments are the same as for
6821 coerce_template_template_parms.
6822 */
6823 static int
6825 tree arg,
6826 tsubst_flags_t complain,
6827 tree in_decl,
6828 tree outer_args)
6829 {
6838 {
6840 /* We encounter instantiations of templates like
6841 template <template <template <class> class> class TT>
6842 class C; */
6843 {
6850 }
6851 /* Fall through. */
6856 /* Argument is a parameter pack but parameter is not. */
6861 /* The tsubst call is used to handle cases such as
6863 template <int> class C {};
6864 template <class T, template <T> class TT> class D {};
6865 D<int, C> d;
6867 i.e. the parameter list of TT depends on earlier parameters. */
6869 {
6874 }
6878 /* Argument is a parameter pack but parameter is not. */
6885 }
6888 }
6890 /* Coerce template argument list ARGLIST for use with template
6891 template-parameter TEMPL. */
6893 static tree
6895 tsubst_flags_t complain)
6896 {
6897 /* Consider an example where a template template parameter declared as
6899 template <class T, class U = std::allocator<T> > class TT
6901 The template parameter level of T and U are one level larger than
6902 of TT. To proper process the default argument of U, say when an
6903 instantiation `TT<int>' is seen, we need to build the full
6904 arguments containing {int} as the innermost level. Outer levels,
6905 available when not appearing as default template argument, can be
6906 obtained from the arguments of the enclosing template.
6908 Suppose that TT is later substituted with std::vector. The above
6909 instantiation is `TT<int, std::allocator<T> >' with TT at
6910 level 1, and T at level 2, while the template arguments at level 1
6911 becomes {std::vector} and the inner level 2 is {int}. */
6915 {
6917 /* We want arguments for the partial specialization, not arguments for
6918 the primary template. */
6920 else
6922 }
6924 {
6925 /* This is an argument of the current template, so we haven't set
6926 DECL_CONTEXT yet. */
6927 tree relevant_template_parms;
6929 /* Parameter levels that are greater than the level of the given
6930 template template parm are irrelevant. */
6937 }
6944 complain,
6947 }
6949 /* A cache of template template parameters with match-all default
6950 arguments. */
6952 static void
6954 {
6958 }
6959 static tree
6961 {
6966 }
6968 /* T is a bound template template-parameter. Copy its arguments into default
6969 arguments of the template template-parameter's template parameters. */
6971 static tree
6973 {
6996 {
6999 {
7002 }
7003 }
7007 }
7009 /* ARG is a bound potential template template-argument, and PARGS is a list
7010 of arguments for the corresponding template template-parameter. Adjust
7011 PARGS as appropriate for application to ARG's template, and if ARG is a
7012 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7013 arguments to the template template parameter. */
7015 static tree
7017 {
7021 {
7022 /* When comparing two template template-parameters in partial ordering,
7023 rewrite the one currently being used as an argument to have default
7024 arguments for all parameters. */
7030 }
7031 else
7032 {
7033 tree aparms
7038 }
7041 }
7043 /* Subroutine of unify for the case when PARM is a
7044 BOUND_TEMPLATE_TEMPLATE_PARM. */
7046 static int
7049 {
7053 /* The template template parm might be variadic and the argument
7054 not, so flatten both argument lists. */
7060 {
7061 /* In keeping with P0522R0, adjust P's template arguments
7062 to apply to A's template; then flatten it again. */
7065 }
7071 /* If the P0522 adjustment eliminated a pack expansion, deduce
7072 empty packs. */
7080 }
7082 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7083 template template parameters. Both PARM_PARMS and ARG_PARMS are
7084 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7085 or PARM_DECL.
7087 Consider the example:
7088 template <class T> class A;
7089 template<template <class U> class TT> class B;
7091 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7092 the parameters to A, and OUTER_ARGS contains A. */
7094 static int
7096 tree arg_parms,
7097 tsubst_flags_t complain,
7098 tree in_decl,
7099 tree outer_args)
7100 {
7112 {
7113 /* P0522R0: A template template-parameter P is at least as specialized as
7114 a template template-argument A if, given the following rewrite to two
7115 function templates, the function template corresponding to P is at
7116 least as specialized as the function template corresponding to A
7117 according to the partial ordering rules for function templates
7118 ([temp.func.order]). Given an invented class template X with the
7119 template parameter list of A (including default arguments):
7121 * Each of the two function templates has the same template parameters,
7122 respectively, as P or A.
7124 * Each function template has a single function parameter whose type is
7125 a specialization of X with template arguments corresponding to the
7126 template parameters from the respective function template where, for
7127 each template parameter PP in the template parameter list of the
7128 function template, a corresponding template argument AA is formed. If
7129 PP declares a parameter pack, then AA is the pack expansion
7130 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7132 If the rewrite produces an invalid type, then P is not at least as
7133 specialized as A. */
7135 /* So coerce P's args to apply to A's parms, and then deduce between A's
7136 args and the converted args. If that succeeds, A is at least as
7137 specialized as P, so they match.*/
7144 {
7150 }
7151 }
7153 /* Determine whether we have a parameter pack at the end of the
7154 template template parameter's template parameter list. */
7156 {
7163 {
7177 }
7178 }
7184 /* Check all of the template parameters except the parameter pack at
7185 the end (if any). */
7187 {
7196 outer_args))
7199 }
7202 {
7203 /* Check each of the template parameters in the template
7204 argument against the template parameter pack at the end of
7205 the template template parameter. */
7212 {
7219 outer_args))
7221 }
7222 }
7225 }
7227 /* Verifies that the deduced template arguments (in TARGS) for the
7228 template template parameters (in TPARMS) represent valid bindings,
7229 by comparing the template parameter list of each template argument
7230 to the template parameter list of its corresponding template
7231 template parameter, in accordance with DR150. This
7232 routine can only be called after all template arguments have been
7233 deduced. It will return TRUE if all of the template template
7234 parameter bindings are okay, FALSE otherwise. */
7235 bool
7237 {
7241 /* We're dealing with template parms in this process. */
7247 {
7252 {
7257 {
7258 /* Look inside the argument pack. */
7261 }
7264 {
7268 /* Extract the next argument from the argument
7269 pack. */
7273 /* Look at the pattern of the pack expansion. */
7276 /* Extract the template parameters from the template
7277 argument. */
7283 /* Verify that we can coerce the template template
7284 parameters from the template argument to the template
7285 parameter. This requires an exact match. */
7287 && !coerce_template_template_parms
7289 targ_parms,
7290 tf_none,
7291 tparm,
7292 targs))
7293 {
7296 }
7297 }
7298 }
7299 }
7301 out:
7305 }
7307 /* Since type attributes aren't mangled, we need to strip them from
7308 template type arguments. */
7310 static tree
7312 {
7322 }
7324 /* And from inside dependent non-type arguments like sizeof(Type). */
7326 static tree
7328 {
7338 }
7340 // A template declaration can be substituted for a constrained
7341 // template template parameter only when the argument is more
7342 // constrained than the parameter.
7343 static bool
7345 {
7348 /* For now, allow constrained template template arguments
7349 and unconstrained template template parameters. */
7355 // If the template parameter is constrained, we need to rewrite its
7356 // constraints in terms of the ARG's template parameters. This ensures
7357 // that all of the template parameter types will have the same depth.
7358 //
7359 // Note that this is only valid when coerce_template_template_parm is
7360 // true for the innermost template parameters of PARM and ARG. In other
7361 // words, because coercion is successful, this conversion will be valid.
7363 {
7370 }
7373 }
7375 // Convert a placeholder argument into a binding to the original
7376 // parameter. The original parameter is saved as the TREE_TYPE of
7377 // ARG.
7380 {
7383 }
7385 /* Convert the indicated template ARG as necessary to match the
7386 indicated template PARM. Returns the converted ARG, or
7387 error_mark_node if the conversion was unsuccessful. Error and
7388 warning messages are issued under control of COMPLAIN. This
7389 conversion is for the Ith parameter in the parameter list. ARGS is
7390 the full set of template arguments deduced so far. */
7392 static tree
7394 tree arg,
7395 tree args,
7396 tsubst_flags_t complain,
7398 tree in_decl)
7399 {
7400 tree orig_arg;
7401 tree val;
7407 /* Trivially convert placeholders. */
7416 {
7417 /* The template argument was the name of some
7418 member function. That's usually
7419 invalid, but static members are OK. In any
7420 case, grab the underlying fields/functions
7421 and issue an error later if required. */
7424 }
7432 /* When determining whether an argument pack expansion is a template,
7433 look at the pattern. */
7437 /* Deal with an injected-class-name used as a template template arg. */
7439 {
7442 {
7452 }
7453 }
7455 is_tmpl_type =
7471 {
7473 {
7477 }
7480 "to refer to a type member of a template parameter, "
7485 typename_type,
7486 complain);
7489 }
7491 {
7493 {
7495 {
7507 else
7510 }
7511 }
7513 }
7515 {
7517 {
7524 else
7527 }
7529 }
7532 {
7534 {
7538 /* The number of argument required is not known yet.
7539 Just accept it for now. */
7541 else
7542 {
7544 tree argparm;
7546 /* Strip alias templates that are equivalent to another
7547 template. */
7553 args))
7554 {
7557 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7558 TEMPLATE_DECL. */
7560 {
7565 }
7566 }
7567 else
7568 {
7570 {
7577 }
7580 }
7582 // Check that the constraints are compatible before allowing the
7583 // substitution.
7586 {
7588 {
7594 }
7596 }
7597 }
7598 }
7599 else
7601 /* We only form one instance of each template specialization.
7602 Therefore, if we use a non-canonical variant (i.e., a
7603 typedef), any future messages referring to the type will use
7604 the typedef, which is confusing if those future uses do not
7605 themselves also use the typedef. */
7608 }
7609 else
7610 {
7614 {
7618 }
7619 else
7626 {
7629 else
7630 {
7631 /* Not sure if this is reachable, but it doesn't hurt
7632 to be robust. */
7635 }
7636 }
7639 /* We used to call digest_init here. However, digest_init
7640 will report errors, which we don't want when complain
7641 is zero. More importantly, digest_init will try too
7642 hard to convert things: for example, `0' should not be
7643 converted to pointer type at this point according to
7644 the standard. Accepting this is not merely an
7645 extension, since deciding whether or not these
7646 conversions can occur is part of determining which
7647 function template to call, or whether a given explicit
7648 argument specification is valid. */
7650 else
7660 {
7661 /* Reject template arguments that are references to built-in
7662 functions with no library fallbacks. */
7671 }
7674 {
7675 /* Strip typedefs from the SCOPE_REF. */
7678 complain);
7681 }
7682 }
7685 }
7687 /* Coerces the remaining template arguments in INNER_ARGS (from
7688 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7689 Returns the coerced argument pack. PARM_IDX is the position of this
7690 parameter in the template parameter list. ARGS is the original
7691 template argument list. */
7692 static tree
7695 tree args,
7696 tree inner_args,
7698 tree new_args,
7700 tree in_decl,
7701 tsubst_flags_t complain)
7702 {
7705 tree packed_args;
7706 tree argument_pack;
7713 {
7714 /* When the template parameter is a non-type template parameter pack
7715 or template template parameter pack whose type or template
7716 parameters use parameter packs, we know exactly how many arguments
7717 we are looking for. Build a vector of the instantiated decls for
7718 these template parameters in PACKED_PARMS. */
7719 /* We can't use make_pack_expansion here because it would interpret a
7720 _DECL as a use rather than a declaration. */
7734 /* If we're doing a partial instantiation of a member template,
7735 verify that all of the types used for the non-type
7736 template parameter pack are, in fact, valid for non-type
7737 template parameters. */
7740 {
7743 {
7747 }
7748 /* We don't know how many args we have yet, just
7749 use the unconverted ones for now. */
7751 }
7754 }
7755 /* Check if we have a placeholder pack, which indicates we're
7756 in the context of a introduction list. In that case we want
7757 to match this pack to the single placeholder. */
7761 {
7764 }
7765 else
7768 /* Convert the remaining arguments, which will be a part of the
7769 parameter pack "parm". */
7772 {
7778 {
7779 /* Once we've packed as many args as we have types, stop. */
7783 /* We don't know how many args we have yet, just
7784 use the unconverted ones for now. */
7786 else
7788 }
7791 {
7794 }
7795 else
7798 in_decl);
7802 }
7806 {
7811 }
7816 else
7817 {
7822 }
7829 }
7831 /* Returns the number of pack expansions in the template argument vector
7832 ARGS. */
7834 static int
7836 {
7841 {
7845 }
7847 }
7849 /* Convert all template arguments to their appropriate types, and
7850 return a vector containing the innermost resulting template
7851 arguments. If any error occurs, return error_mark_node. Error and
7852 warning messages are issued under control of COMPLAIN.
7854 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7855 for arguments not specified in ARGS. Otherwise, if
7856 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7857 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7858 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7859 ARGS. */
7861 static tree
7863 tree args,
7864 tree in_decl,
7865 tsubst_flags_t complain,
7868 {
7870 tree orig_inner_args;
7871 tree inner_args;
7872 tree new_args;
7873 tree new_inner_args;
7877 /* When used as a boolean value, indicates whether this is a
7878 variadic template parameter list. Since it's an int, we can also
7879 subtract it from nparms to get the number of non-variadic
7880 parameters. */
7885 /* Likewise for parameters with default arguments. */
7893 /* Determine if there are any parameter packs or default arguments. */
7895 {
7903 }
7906 /* If there are no parameters that follow a parameter pack, we need to
7907 expand any argument packs so that we can deduce a parameter pack from
7908 some non-packed args followed by an argument pack, as in variadic85.C.
7909 If there are such parameters, we need to leave argument packs intact
7910 so the arguments are assigned properly. This can happen when dealing
7911 with a nested class inside a partial specialization of a class
7912 template, as in variadic92.C, or when deducing a template parameter pack
7913 from a sub-declarator, as in variadic114.C. */
7917 /* Count any pack expansion args. */
7923 && require_all_args
7924 && !variadic_args_p
7925 && (!use_default_args
7928 {
7930 {
7932 {
7936 }
7937 else
7944 }
7947 }
7948 /* We can't pass a pack expansion to a non-pack parameter of an alias
7949 template (DR 1430). */
7953 && variadic_args_p
7955 {
7957 {
7959 {
7965 {
7968 "pack expansion argument for non-pack parameter "
7970 else
7972 "pack expansion argument for non-pack parameter "
7976 }
7977 }
7979 found:;
7980 }
7982 }
7984 /* We need to evaluate the template arguments, even though this
7985 template-id may be nested within a "sizeof". */
7994 {
7995 tree arg;
7996 tree parm;
7998 /* Get the Ith template parameter. */
8002 {
8005 }
8007 /* Calculate the next argument. */
8010 else
8015 {
8016 /* Some arguments will be placed in the
8017 template parameter pack PARM. */
8024 {
8025 /* We don't know how many args we have yet, just use the
8026 unconverted (and still packed) ones for now. */
8030 }
8034 /* Store this argument. */
8036 {
8037 lost++;
8038 /* We are done with all of the arguments. */
8040 }
8041 else
8042 {
8045 }
8048 }
8050 {
8052 {
8053 /* "If every valid specialization of a variadic template
8054 requires an empty template parameter pack, the template is
8055 ill-formed, no diagnostic required." So check that the
8056 pattern works with this parameter. */
8061 in_decl);
8063 {
8068 }
8070 /* Recover from missing typename. */
8074 /* We don't know how many args we have yet, just
8075 use the unconverted ones for now. */
8079 }
8080 }
8082 {
8083 /* There must be a default arg in this case. */
8086 /* The position of the first default template argument,
8087 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8088 Record that. */
8092 }
8093 else
8097 {
8100 }
8102 /* This only occurs if there was an error in the template
8103 parameter list itself (which we would already have
8104 reported) that we are trying to recover from, e.g., a class
8105 template with a parameter list such as
8106 template<typename..., typename>. */
8108 else
8114 lost++;
8116 }
8121 {
8123 {
8128 }
8130 }
8140 }
8142 /* Convert all template arguments to their appropriate types, and
8143 return a vector containing the innermost resulting template
8144 arguments. If any error occurs, return error_mark_node. Error and
8145 warning messages are not issued.
8147 Note that no function argument deduction is performed, and default
8148 arguments are used to fill in unspecified arguments. */
8149 tree
8151 {
8153 }
8155 /* Convert all template arguments to their appropriate type, and
8156 instantiate default arguments as needed. This returns a vector
8157 containing the innermost resulting template arguments, or
8158 error_mark_node if unsuccessful. */
8159 tree
8161 tsubst_flags_t complain)
8162 {
8164 }
8166 /* Like coerce_template_parms. If PARMS represents all template
8167 parameters levels, this function returns a vector of vectors
8168 representing all the resulting argument levels. Note that in this
8169 case, only the innermost arguments are coerced because the
8170 outermost ones are supposed to have been coerced already.
8172 Otherwise, if PARMS represents only (the innermost) vector of
8173 parameters, this function returns a vector containing just the
8174 innermost resulting arguments. */
8176 static tree
8178 tree args,
8179 tree in_decl,
8180 tsubst_flags_t complain,
8183 {
8186 tree coerced_args;
8189 {
8191 tree level;
8197 {
8198 tree l;
8202 require_all_args,
8203 use_default_args);
8204 else
8211 }
8212 }
8213 else
8216 require_all_args,
8217 use_default_args);
8219 }
8221 /* Returns 1 if template args OT and NT are equivalent. */
8223 int
8225 {
8234 /* For member templates */
8243 {
8260 }
8264 {
8267 /* Don't treat an alias template specialization with dependent
8268 arguments as equivalent to its underlying type when used as a
8269 template argument; we need them to be distinct so that we
8270 substitute into the specialization arguments at instantiation
8271 time. And aliases can't be equivalent without being ==, so
8272 we don't need to look any deeper. */
8275 else
8277 }
8280 else
8281 {
8282 /* Try to treat a template non-type argument that has been converted
8283 to the parameter type as equivalent to one that hasn't yet. */
8296 }
8297 }
8299 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8300 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8301 NEWARG_PTR with the offending arguments if they are non-NULL. */
8303 int
8306 {
8319 {
8324 {
8330 }
8331 }
8333 }
8335 static void
8337 {
8347 /* We are called both from instantiate_decl, where we've already had a
8348 tinst_level pushed, and instantiate_template, where we haven't.
8349 Compensate. */
8360 else
8369 }
8372 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8373 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8374 documentation for TEMPLATE_ID_EXPR. */
8376 tree
8378 {
8379 tree type;
8387 {
8390 }
8393 {
8395 unknown_type_node,
8397 arglist);
8399 }
8406 }
8408 /* Within the scope of a template class S<T>, the name S gets bound
8409 (in build_self_reference) to a TYPE_DECL for the class, not a
8410 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8411 or one of its enclosing classes, and that type is a template,
8412 return the associated TEMPLATE_DECL. Otherwise, the original
8413 DECL is returned.
8415 Also handle the case when DECL is a TREE_LIST of ambiguous
8416 injected-class-names from different bases. */
8418 tree
8420 {
8424 /* DR 176: A lookup that finds an injected-class-name (10.2
8425 [class.member.lookup]) can result in an ambiguity in certain cases
8426 (for example, if it is found in more than one base class). If all of
8427 the injected-class-names that are found refer to specializations of
8428 the same class template, and if the name is followed by a
8429 template-argument-list, the reference refers to the class template
8430 itself and not a specialization thereof, and is not ambiguous. */
8432 {
8435 {
8441 }
8444 else
8446 }
8452 }
8454 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8455 parameters, find the desired type.
8457 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8459 IN_DECL, if non-NULL, is the template declaration we are trying to
8460 instantiate.
8462 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8463 the class we are looking up.
8465 Issue error and warning messages under control of COMPLAIN.
8467 If the template class is really a local class in a template
8468 function, then the FUNCTION_CONTEXT is the function in which it is
8469 being instantiated.
8471 ??? Note that this function is currently called *twice* for each
8472 template-id: the first time from the parser, while creating the
8473 incomplete type (finish_template_type), and the second type during the
8474 real instantiation (instantiate_template_class). This is surely something
8475 that we want to avoid. It also causes some problems with argument
8476 coercion (see convert_nontype_argument for more information on this). */
8478 static tree
8481 {
8483 tree t;
8486 spec_entry elt;
8487 hashval_t hash;
8490 {
8494 else
8495 {
8502 }
8505 }
8507 {
8510 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8511 an implicit typename for the second A. Deal with it. */
8516 {
8519 }
8520 }
8523 {
8526 }
8528 {
8532 }
8534 {
8537 }
8539 /* Issue an error message if we didn't find a template. */
8541 {
8545 }
8548 /* Make sure it's a user visible template, if it was named by
8549 the user. */
8552 {
8554 {
8558 }
8560 }
8564 /* An alias that just changes the name of a template is equivalent to the
8565 other template, so if any of the arguments are pack expansions, strip
8566 the alias to avoid problems with a pack expansion passed to a non-pack
8567 alias template parameter (DR 1430). */
8572 {
8573 tree parm;
8582 }
8583 else
8584 {
8586 tree gen_tmpl;
8587 tree type_decl;
8595 /* An error occurred while building the template TEMPL, and a
8596 diagnostic has most certainly been emitted for that
8597 already. Let's propagate that error. */
8606 {
8607 /* We've been given an incomplete set of template arguments.
8608 For example, given:
8610 template <class T> struct S1 {
8611 template <class U> struct S2 {};
8612 template <class U> struct S2<U*> {};
8613 };
8615 we will be called with an ARGLIST of `U*', but the
8616 TEMPLATE will be `template <class T> template
8617 <class U> struct S1<T>::S2'. We must fill in the missing
8618 arguments. */
8622 }
8624 /* Now we should have enough arguments. */
8627 /* From here on, we're only interested in the most general
8628 template. */
8630 /* Calculate the BOUND_ARGS. These will be the args that are
8631 actually tsubst'd into the definition to create the
8632 instantiation. */
8634 complain,
8639 /* We were unable to bind the arguments. */
8642 /* In the scope of a template class, explicit references to the
8643 template class refer to the type of the template, not any
8644 instantiation of it. For example, in:
8646 template <class T> class C { void f(C<T>); }
8648 the `C<T>' is just the same as `C'. Outside of the
8649 class, however, such a reference is an instantiation. */
8653 {
8658 }
8660 /* If we already have this specialization, return it. */
8670 /* If the the template's constraints are not satisfied,
8671 then we cannot form a valid type.
8673 Note that the check is deferred until after the hash
8674 lookup. This prevents redundant checks on previously
8675 instantiated specializations. */
8677 {
8679 {
8682 }
8684 }
8688 /* If the deduced arguments are invalid, then the binding
8689 failed. */
8693 complain))
8700 {
8705 }
8715 /* Create the type. */
8717 {
8718 /* The user referred to a specialization of an alias
8719 template represented by GEN_TMPL.
8721 [temp.alias]/2 says:
8723 When a template-id refers to the specialization of an
8724 alias template, it is equivalent to the associated
8725 type obtained by substitution of its
8726 template-arguments for the template-parameters in the
8727 type-id of the alias template. */
8730 /* Note that the call above (by indirectly calling
8731 register_specialization in tsubst_decl) registers the
8732 TYPE_DECL representing the specialization of the alias
8733 template. So next time someone substitutes ARGLIST for
8734 the template parms into the alias template (GEN_TMPL),
8735 she'll get that TYPE_DECL back. */
8739 }
8741 {
8743 {
8754 }
8755 else
8756 {
8757 /* We don't want to call start_enum for this type, since
8758 the values for the enumeration constants may involve
8759 template parameters. And, no one should be interested
8760 in the enumeration constants for such a type. */
8763 }
8767 }
8769 {
8775 /* A local class. Make sure the decl gets registered properly. */
8780 /* This instantiation is another name for the primary
8781 template type. Set the TYPE_CANONICAL field
8782 appropriately. */
8785 /* Some of the template arguments require structural
8786 equality testing, so this template class requires
8787 structural equality testing. */
8789 }
8790 else
8793 /* If we called start_enum or pushtag above, this information
8794 will already be set up. */
8796 {
8803 }
8804 else
8808 {
8814 {
8817 }
8818 }
8822 {
8826 {
8827 tree attributes
8835 }
8836 }
8838 /* Let's consider the explicit specialization of a member
8839 of a class template specialization that is implicitly instantiated,
8840 e.g.:
8841 template<class T>
8842 struct S
8843 {
8844 template<class U> struct M {}; //#0
8845 };
8847 template<>
8848 template<>
8849 struct S<int>::M<char> //#1
8850 {
8851 int i;
8852 };
8853 [temp.expl.spec]/4 says this is valid.
8855 In this case, when we write:
8856 S<int>::M<char> m;
8858 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8859 the one of #0.
8861 When we encounter #1, we want to store the partial instantiation
8862 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8864 For all cases other than this "explicit specialization of member of a
8865 class template", we just want to store the most general template into
8866 the CLASSTYPE_TI_TEMPLATE of M.
8868 This case of "explicit specialization of member of a class template"
8869 only happens when:
8870 1/ the enclosing class is an instantiation of, and therefore not
8871 the same as, the context of the most general template, and
8872 2/ we aren't looking at the partial instantiation itself, i.e.
8873 the innermost arguments are not the same as the innermost parms of
8874 the most general template.
8876 So it's only when 1/ and 2/ happens that we want to use the partial
8877 instantiation of the member template in lieu of its most general
8878 template. */
8882 /* the enclosing class must be an instantiation... */
8885 {
8889 tree partial_inst_args =
8896 use_partial_inst_tmpl =
8897 /*...and we must not be looking at the partial instantiation
8898 itself. */
8900 partial_inst_args);
8901 }
8904 /* This case is easy; there are no member templates involved. */
8906 else
8907 {
8908 /* This is a full instantiation of a member template. Find
8909 the partial instantiation of which this is an instance. */
8911 /* Temporarily reduce by one the number of levels in the ARGLIST
8912 so as to avoid comparing the last set of arguments. */
8916 /* FOUND is either a proper class type, or an alias
8917 template specialization. In the later case, it's a
8918 TYPE_DECL, resulting from the substituting of arguments
8919 for parameters in the TYPE_DECL of the alias template
8920 done earlier. So be careful while getting the template
8921 of FOUND. */
8923 ? found
8927 }
8929 // Build template info for the new specialization.
8938 /* Note this use of the partial instantiation so we can check it
8939 later in maybe_process_partial_specialization. */
8946 /* Now that the type has been registered on the instantiations
8947 list, we set up the enumerators. Because the enumeration
8948 constants may involve the enumeration type itself, we make
8949 sure to register the type first, and then create the
8950 constants. That way, doing tsubst_expr for the enumeration
8951 constants won't result in recursive calls here; we'll find
8952 the instantiation and exit above. */
8956 /* If the type makes use of template parameters, the
8957 code that generates debugging information will crash. */
8960 /* Possibly limit visibility based on template args. */
8967 }
8968 }
8970 /* Wrapper for lookup_template_class_1. */
8972 tree
8975 {
8976 tree ret;
8982 }
8984 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
8986 tree
8988 {
8989 /* The type of the expression is NULL_TREE since the template-id could refer
8990 to an explicit or partial specialization. */
8993 /* Except that concepts are always bool. */
8996 }
8998 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9000 tree
9002 {
9006 /* We never want to return a VAR_DECL for a variable concept, since they
9007 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9022 {
9024 {
9027 }
9029 }
9031 /* If a template-id refers to a specialization of a variable
9032 concept, then the expression is true if and only if the
9033 concept's constraints are satisfied by the given template
9034 arguments.
9036 NOTE: This is an extension of Concepts Lite TS that
9037 allows constraints to be used in expressions. */
9039 {
9042 }
9045 }
9047 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9048 TARGS template args, and instantiate it if it's not dependent. */
9050 tree
9052 tsubst_flags_t complain)
9053 {
9056 {
9059 }
9062 }
9064 \f
9065 struct pair_fn_data
9066 {
9067 tree_fn_t fn;
9068 tree_fn_t any_fn;
9070 /* True when we should also visit template parameters that occur in
9071 non-deduced contexts. */
9074 };
9076 /* Called from for_each_template_parm via walk_tree. */
9078 static tree
9080 {
9087 #define WALK_SUBTREE(NODE) \
9088 do \
9089 { \
9090 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9091 pfd->include_nondeduced_p, \
9092 pfd->any_fn); \
9093 if (result) goto out; \
9094 } \
9095 while (0)
9105 {
9109 /* Fall through. */
9115 else
9125 /* Since we're not going to walk subtrees, we have to do this
9126 explicitly here. */
9128 /* Fall through. */
9131 /* Check the return type. */
9134 /* Check the parameter types. Since default arguments are not
9135 instantiated until they are needed, the TYPE_ARG_TYPES may
9136 contain expressions that involve template parameters. But,
9137 no-one should be looking at them yet. And, once they're
9138 instantiated, they don't contain template parameters, so
9139 there's no point in looking at them then, either. */
9140 {
9141 tree parm;
9146 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9147 want walk_tree walking into them itself. */
9149 }
9152 {
9156 }
9173 /* Fall through. */
9185 /* Record template parameters such as `T' inside `TT<T>'. */
9187 /* Fall through. */
9199 /* A template template parameter is encountered. */
9203 /* Already substituted template template parameter */
9208 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9209 partial instantiation. */
9221 /* If there's no type, then this thing must be some expression
9222 involving template parameters. */
9244 }
9246 #undef WALK_SUBTREE
9248 /* We didn't find any template parameters we liked. */
9249 out:
9251 }
9253 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9254 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9255 call FN with the parameter and the DATA.
9256 If FN returns nonzero, the iteration is terminated, and
9257 for_each_template_parm returns 1. Otherwise, the iteration
9258 continues. If FN never returns a nonzero value, the value
9259 returned by for_each_template_parm is 0. If FN is NULL, it is
9260 considered to be the function which always returns 1.
9262 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9263 parameters that occur in non-deduced contexts. When false, only
9264 visits those template parameters that can be deduced. */
9266 static tree
9270 tree_fn_t any_fn)
9271 {
9273 tree result;
9275 /* Set up. */
9281 /* Walk the tree. (Conceptually, we would like to walk without
9282 duplicates, but for_each_template_parm_r recursively calls
9283 for_each_template_parm, so we would need to reorganize a fair
9284 bit to use walk_tree_without_duplicates, so we keep our own
9285 visited list.) */
9288 else
9291 for_each_template_parm_r,
9295 /* Clean up. */
9297 {
9300 }
9303 }
9305 /* Returns true if T depends on any template parameter. */
9307 int
9309 {
9339 else
9340 {
9343 }
9348 }
9350 /* Returns true iff current_function_decl is an incompletely instantiated
9351 template. Useful instead of processing_template_decl because the latter
9352 is set to 0 during instantiate_non_dependent_expr. */
9354 bool
9356 {
9365 }
9367 /* Returns true if T depends on any template parameter with level LEVEL. */
9369 bool
9371 {
9374 }
9376 /* Returns true if the signature of DECL depends on any template parameter from
9377 its enclosing class. */
9379 bool
9381 {
9391 template_parm_outer_level,
9401 }
9403 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9404 ill-formed translation unit, i.e. a variable or function that isn't
9405 usable in a constant expression. */
9409 {
9413 }
9415 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9416 neglectable and instantiated from within an erroneous instantiation. */
9418 static bool
9420 {
9431 }
9439 /* We're starting to instantiate D; record the template instantiation context
9440 for diagnostics and to restore it later. */
9442 bool
9444 {
9446 }
9448 /* We're starting to instantiate D; record the template instantiation context
9449 at LOC for diagnostics and to restore it later. */
9451 bool
9453 {
9457 {
9458 /* Tell error.c not to try to instantiate any templates. */
9461 "template instantiation depth exceeds maximum of %d"
9463 max_tinst_depth);
9465 }
9467 /* If the current instantiation caused problems, don't let it instantiate
9468 anything else. Do allow deduction substitution and decls usable in
9469 constant expressions. */
9473 /* When not -quiet, dump template instantiations other than functions, since
9474 announce_function will take care of those. */
9493 }
9495 /* We're done instantiating this template; return to the instantiation
9496 context. */
9498 void
9500 {
9501 /* Restore the filename and line number stashed away when we started
9502 this instantiation. */
9506 }
9508 /* We're instantiating a deferred template; restore the template
9509 instantiation context in which the instantiation was requested, which
9510 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9512 static tree
9514 {
9526 }
9528 /* Returns the TINST_LEVEL which gives the original instantiation
9529 context. */
9533 {
9539 }
9541 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9542 vector of template arguments, as for tsubst.
9544 Returns an appropriate tsubst'd friend declaration. */
9546 static tree
9548 {
9549 tree new_friend;
9554 /* This was a friend declared with an explicit template
9555 argument list, e.g.:
9557 friend void f<>(T);
9559 to indicate that f was a template instantiation, not a new
9560 function declaration. Now, we have to figure out what
9561 instantiation of what template. */
9562 {
9564 tree new_args;
9565 tree tmpl;
9568 /* Friend functions are looked up in the containing namespace scope.
9569 We must enter that scope, to avoid finding member functions of the
9570 current class with same name. */
9585 tsk_none);
9587 }
9591 /* The NEW_FRIEND will look like an instantiation, to the
9592 compiler, but is not an instantiation from the point of view of
9593 the language. For example, we might have had:
9595 template <class T> struct S {
9596 template <class U> friend void f(T, U);
9597 };
9599 Then, in S<int>, template <class U> void f(int, U) is not an
9600 instantiation of anything. */
9606 {
9610 }
9612 /* The mangled name for the NEW_FRIEND is incorrect. The function
9613 is not a template instantiation and should not be mangled like
9614 one. Therefore, we forget the mangling here; we'll recompute it
9615 later if we need it. */
9617 {
9620 }
9623 {
9624 tree old_decl;
9625 tree new_friend_template_info;
9626 tree new_friend_result_template_info;
9627 tree ns;
9630 /* We must save some information from NEW_FRIEND before calling
9631 duplicate decls since that function will free NEW_FRIEND if
9632 possible. */
9634 new_friend_is_defn =
9639 {
9640 /* This declaration is a `primary' template. */
9643 new_friend_result_template_info
9645 }
9646 else
9649 /* Inside pushdecl_namespace_level, we will push into the
9650 current namespace. However, the friend function should go
9651 into the namespace of the template. */
9661 {
9662 /* This new friend declaration matched an existing
9663 declaration. For example, given:
9665 template <class T> void f(T);
9666 template <class U> class C {
9667 template <class T> friend void f(T) {}
9668 };
9670 the friend declaration actually provides the definition
9671 of `f', once C has been instantiated for some type. So,
9672 old_decl will be the out-of-class template declaration,
9673 while new_friend is the in-class definition.
9675 But, if `f' was called before this point, the
9676 instantiation of `f' will have DECL_TI_ARGS corresponding
9677 to `T' but not to `U', references to which might appear
9678 in the definition of `f'. Previously, the most general
9679 template for an instantiation of `f' was the out-of-class
9680 version; now it is the in-class version. Therefore, we
9681 run through all specialization of `f', adding to their
9682 DECL_TI_ARGS appropriately. In particular, they need a
9683 new set of outer arguments, corresponding to the
9684 arguments for this class instantiation.
9686 The same situation can arise with something like this:
9688 friend void f(int);
9689 template <class T> class C {
9690 friend void f(T) {}
9691 };
9693 when `C<int>' is instantiated. Now, `f(int)' is defined
9694 in the class. */
9697 /* On the other hand, if the in-class declaration does
9698 *not* provide a definition, then we don't want to alter
9699 existing definitions. We can just leave everything
9700 alone. */
9701 ;
9702 else
9703 {
9707 /* Overwrite whatever template info was there before, if
9708 any, with the new template information pertaining to
9709 the declaration. */
9713 {
9714 /* We should have called reregister_specialization in
9715 duplicate_decls. */
9720 /* Instantiate it if the global has already been used. */
9724 }
9725 else
9726 {
9727 tree t;
9729 /* Indicate that the old function template is a partial
9730 instantiation. */
9738 /* Reassign any specializations already in the hash table
9739 to the new more general template, and add the
9740 additional template args. */
9744 {
9746 spec_entry elt;
9758 register_specialization
9761 }
9763 }
9764 }
9766 /* The information from NEW_FRIEND has been merged into OLD_DECL
9767 by duplicate_decls. */
9769 }
9770 }
9771 else
9772 {
9776 /* In the code
9777 template <class T> class C {
9778 template <class U> friend void C1<U>::f (); // case 1
9779 friend void C2<T>::f (); // case 2
9780 };
9781 we only need to make sure CONTEXT is a complete type for
9782 case 2. To distinguish between the two cases, we note that
9783 CONTEXT of case 1 remains dependent type after tsubst while
9784 this isn't true for case 2. */
9794 {
9796 /* do_friend adds the TEMPLATE_DECL for any member friend
9797 template even if it isn't a member template, i.e.
9798 template <class T> friend A<T>::f();
9799 Look through it in that case. */
9803 /* Check to see that the declaration is really present, and,
9804 possibly obtain an improved declaration. */
9809 }
9810 }
9813 }
9815 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9816 template arguments, as for tsubst.
9818 Returns an appropriate tsubst'd friend type or error_mark_node on
9819 failure. */
9821 static tree
9823 {
9824 tree friend_type;
9825 tree tmpl;
9826 tree context;
9829 {
9832 }
9837 {
9840 else
9842 }
9844 /* Look for a class template declaration. We look for hidden names
9845 because two friend declarations of the same template are the
9846 same. For example, in:
9848 struct A {
9849 template <typename> friend class F;
9850 };
9851 template <typename> struct B {
9852 template <typename> friend class F;
9853 };
9855 both F templates are the same. */
9859 /* But, if we don't find one, it might be because we're in a
9860 situation like this:
9862 template <class T>
9863 struct S {
9864 template <class U>
9865 friend struct S;
9866 };
9868 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9869 for `S<int>', not the TEMPLATE_DECL. */
9871 {
9874 }
9877 {
9878 /* The friend template has already been declared. Just
9879 check to see that the declarations match, and install any new
9880 default parameters. We must tsubst the default parameters,
9881 of course. We only need the innermost template parameters
9882 because that is all that redeclare_class_template will look
9883 at. */
9886 {
9887 tree parms;
9888 location_t saved_input_location;
9898 }
9901 }
9902 else
9903 {
9904 /* The friend template has not already been declared. In this
9905 case, the instantiation of the template class will cause the
9906 injection of this template into the global scope. */
9911 /* The new TMPL is not an instantiation of anything, so we
9912 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9913 the new type because that is supposed to be the corresponding
9914 template decl, i.e., TMPL. */
9921 /* Inject this template into the global scope. */
9923 }
9926 {
9929 else
9931 }
9934 }
9936 /* Returns zero if TYPE cannot be completed later due to circularity.
9937 Otherwise returns one. */
9939 static int
9941 {
9951 else
9953 }
9958 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
9959 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
9961 static tree
9964 {
9973 {
9980 clauses
9984 else
9986 }
9987 /* If the first attribute argument is an identifier, don't
9988 pass it through tsubst. Attributes like mode, format,
9989 cleanup and several target specific attributes expect it
9990 unmodified. */
9992 {
9993 tree chain
9998 }
10000 {
10001 /* An attribute pack expansion. */
10008 {
10012 }
10014 }
10015 else
10022 }
10024 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10025 unchanged or a new TREE_LIST chain. */
10027 static tree
10030 {
10035 {
10039 }
10043 {
10046 {
10049 {
10051 do
10056 }
10057 }
10059 }
10062 }
10064 /* Apply any attributes which had to be deferred until instantiation
10065 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10066 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10068 static void
10071 {
10073 tree t;
10078 {
10082 }
10085 {
10089 }
10090 else
10094 {
10099 {
10102 {
10106 do
10109 }
10110 else
10112 }
10115 }
10116 }
10118 /* Perform (or defer) access check for typedefs that were referenced
10119 from within the template TMPL code.
10120 This is a subroutine of instantiate_decl and instantiate_class_template.
10121 TMPL is the template to consider and TARGS is the list of arguments of
10122 that template. */
10124 static void
10126 {
10127 location_t saved_location;
10138 {
10150 /* Make access check error messages point to the location
10151 of the use of the typedef. */
10155 tf_warning_or_error);
10156 }
10158 }
10160 static tree
10162 {
10164 tree typedecl;
10165 tree pbinfo;
10166 tree base_list;
10168 tree fn_context;
10177 /* Figure out which template is being instantiated. */
10181 /* Determine what specialization of the original template to
10182 instantiate. */
10185 {
10188 }
10190 {
10191 /* This TYPE is actually an instantiation of a partial
10192 specialization. We replace the innermost set of ARGS with
10193 the arguments appropriate for substitution. For example,
10194 given:
10196 template <class T> struct S {};
10197 template <class T> struct S<T*> {};
10199 and supposing that we are instantiating S<int*>, ARGS will
10200 presently be {int*} -- but we need {int}. */
10203 }
10204 else
10205 {
10208 }
10210 /* If the template we're instantiating is incomplete, then clearly
10211 there's nothing we can do. */
10215 /* If we've recursively instantiated too many templates, stop. */
10219 /* Now we're really doing the instantiation. Mark the type as in
10220 the process of being defined. */
10223 /* We may be in the middle of deferred access check. Disable
10224 it now. */
10231 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10236 else
10237 {
10240 }
10241 /* Use #pragma pack from the template context. */
10247 /* Set the input location to the most specialized template definition.
10248 This is needed if tsubsting causes an error. */
10259 {
10262 /* Adjust visibility for template arguments. */
10264 }
10270 /* We should never instantiate a nested class before its enclosing
10271 class; we need to look up the nested class by name before we can
10272 instantiate it, and that lookup should instantiate the enclosing
10273 class. */
10279 {
10280 tree pbase_binfo;
10281 tree pushed_scope;
10284 /* We must enter the scope containing the type, as that is where
10285 the accessibility of types named in dependent bases are
10286 looked up from. */
10289 /* Substitute into each of the bases to determine the actual
10290 basetypes. */
10292 {
10293 tree base;
10299 {
10300 expanded_bases =
10307 }
10310 {
10312 /* Extract the already-expanded base class. */
10314 else
10315 /* Substitute to figure out the base class. */
10317 NULL_TREE);
10325 }
10326 }
10328 /* The list is now in reverse order; correct that. */
10333 }
10334 /* Now call xref_basetypes to set up all the base-class
10335 information. */
10343 /* Now that our base classes are set up, enter the scope of the
10344 class, so that name lookups into base classes, etc. will work
10345 correctly. This is precisely analogous to what we do in
10346 begin_class_definition when defining an ordinary non-template
10347 class, except we also need to push the enclosing classes. */
10350 /* Now members are processed in the order of declaration. */
10353 {
10357 {
10359 {
10360 /* Build new CLASSTYPE_NESTED_UTDS. */
10362 tree newtag;
10368 /* If the member is a class template, then -- even after
10369 substitution -- there may be dependent types in the
10370 template argument list for the class. We increment
10371 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10372 that function will assume that no types are dependent
10373 when outside of a template. */
10383 {
10387 /* Unfortunately, lookup_template_class sets
10388 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10389 instantiation (i.e., for the type of a member
10390 template class nested within a template class.)
10391 This behavior is required for
10392 maybe_process_partial_specialization to work
10393 correctly, but is not accurate in this case;
10394 the TAG is not an instantiation of anything.
10395 (The corresponding TEMPLATE_DECL is an
10396 instantiation, but the TYPE is not.) */
10399 /* Now, we call pushtag to put this NEWTAG into the scope of
10400 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10401 pushtag calling push_template_decl. We don't have to do
10402 this for enums because it will already have been done in
10403 tsubst_enum. */
10407 }
10408 }
10410 {
10411 /* Build new TYPE_METHODS. */
10412 tree r;
10421 /* Instantiate members marked with attribute used. */
10427 }
10430 /* A closure type for a lambda in a default argument for a
10431 member template. Ignore it; it will be instantiated with
10433 else
10434 {
10435 /* Build new TYPE_FIELDS. */
10437 {
10438 tree condition;
10441 condition =
10451 }
10453 {
10454 tree r;
10458 /* The file and line for this declaration, to
10459 assist in error message reporting. Since we
10460 called push_tinst_level above, we don't need to
10461 restore these. */
10471 {
10472 /* A capture pack became multiple fields. */
10475 }
10478 {
10482 {
10483 /* In [temp.inst]:
10485 [t]he initialization (and any associated
10486 side-effects) of a static data member does
10487 not occur unless the static data member is
10488 itself used in a way that requires the
10489 definition of the static data member to
10490 exist.
10492 Therefore, we do not substitute into the
10493 initialized for the static data member here. */
10494 finish_static_data_member_decl
10500 /* Instantiate members marked with attribute used. */
10503 }
10505 {
10506 /* Determine whether R has a valid type and can be
10507 completed later. If R is invalid, then its type
10508 is replaced by error_mark_node. */
10514 {
10515 /* If R's type couldn't be completed and
10516 it isn't a flexible array member (whose
10517 type is incomplete by definition) give
10518 an error. */
10521 }
10522 }
10524 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10525 such a thing will already have been added to the field
10526 list by tsubst_enum in finish_member_declaration in the
10527 CLASSTYPE_NESTED_UTDS case above. */
10531 {
10534 }
10535 }
10536 }
10537 }
10538 }
10539 else
10540 {
10543 {
10544 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10550 {
10551 /* template <class T> friend class C; */
10554 }
10556 {
10557 /* template <class T> friend class C::D; */
10563 }
10566 {
10567 /* This could be either
10569 friend class T::C;
10571 when dependent_type_p is false or
10573 template <class U> friend class T::C;
10575 otherwise. */
10576 /* Bump processing_template_decl in case this is something like
10577 template <class T> friend struct A<T>::B. */
10584 }
10587 {
10588 /* friend class C;
10590 where C hasn't been declared yet. Let's lookup name
10591 from namespace scope directly, bypassing any name that
10592 come from dependent base class. */
10595 /* The call to xref_tag_from_type does injection for friend
10596 classes. */
10598 friend_type =
10602 }
10604 /* friend class C<T>; */
10607 /* Otherwise it's
10609 friend class C;
10611 where C is already declared or
10613 friend class C<int>;
10615 We don't have to do anything in these cases. */
10618 /* Trick make_friend_class into realizing that the friend
10619 we're adding is a template, not an ordinary class. It's
10620 important that we use make_friend_class since it will
10621 perform some error-checking and output cross-reference
10622 information. */
10630 }
10631 else
10632 {
10633 /* Build new DECL_FRIENDLIST. */
10634 tree r;
10636 /* The file and line for this declaration, to
10637 assist in error message reporting. Since we
10638 called push_tinst_level above, we don't need to
10639 restore these. */
10643 {
10646 }
10651 {
10654 }
10655 }
10656 }
10657 }
10660 {
10661 /* Restore these before substituting into the lambda capture
10662 initializers. */
10665 }
10668 {
10671 {
10677 {
10678 /* Set function_depth to avoid garbage collection. */
10682 }
10684 /* We need to instantiate the capture list from the template
10685 after we've instantiated the closure members, but before we
10686 consider adding the conversion op. Also keep any captures
10687 that may have been added during instantiation of the op(). */
10689 tree tmpl_cap
10698 }
10699 else
10701 }
10703 /* Set the file and line number information to whatever is given for
10704 the class itself. This puts error messages involving generated
10705 implicit functions at a predictable point, and the same point
10706 that would be used for non-template classes. */
10713 /* We don't instantiate default arguments for member functions. 14.7.1:
10715 The implicit instantiation of a class template specialization causes
10716 the implicit instantiation of the declarations, but not of the
10717 definitions or default arguments, of the class member functions,
10718 member classes, static data members and member templates.... */
10720 /* Some typedefs referenced from within the template code need to be access
10721 checked at template instantiation time, i.e now. These types were
10722 added to the template at parsing time. Let's get those and perform
10723 the access checks then. */
10733 /* The vtable for a template class can be emitted in any translation
10734 unit in which the class is instantiated. When there is no key
10735 method, however, finish_struct_1 will already have added TYPE to
10736 the keyed_classes list. */
10741 }
10743 /* Wrapper for instantiate_class_template_1. */
10745 tree
10747 {
10748 tree ret;
10753 }
10755 static tree
10757 {
10758 tree r;
10764 else
10765 {
10772 }
10774 }
10776 /* Given a function parameter pack TMPL_PARM and some function parameters
10777 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10778 and set *SPEC_P to point at the next point in the list. */
10780 tree
10782 {
10783 /* Collect all of the extra "packed" parameters into an
10784 argument pack. */
10785 tree parmvec;
10786 tree parmtypevec;
10797 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10802 {
10805 }
10807 /* Build the argument packs. */
10814 }
10816 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10817 NONTYPE_ARGUMENT_PACK. */
10819 static tree
10821 {
10823 }
10825 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10826 pack expansion with no extra args, 2 if it has extra args, or 0
10827 if it is not a pack expansion. */
10829 static int
10831 {
10837 /* A decl pack is itself an expansion. */
10844 }
10847 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10849 static tree
10851 {
10858 }
10860 /* This is a subroutine of tsubst_pack_expansion.
10862 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10863 mechanism to store the (non complete list of) arguments of the
10864 substitution and return a non substituted pack expansion, in order
10865 to wait for when we have enough arguments to really perform the
10866 substitution. */
10868 static bool
10872 {
10873 /* If one pack has an expansion and another pack has a normal
10874 argument or if one pack has an empty argument and an another
10875 one hasn't then tsubst_pack_expansion cannot perform the
10876 substitution and need to fall back on the
10877 PACK_EXPANSION_EXTRA mechanism. */
10885 {
10888 parm_pack;
10890 {
10895 /* We can't substitute a pack expansion with extra args into
10896 our pattern. */
10900 else
10902 }
10906 }
10908 }
10910 /* [temp.variadic]/6 says that:
10912 The instantiation of a pack expansion [...]
10913 produces a list E1,E2, ..., En, where N is the number of elements
10914 in the pack expansion parameters.
10916 This subroutine of tsubst_pack_expansion produces one of these Ei.
10918 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10919 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10920 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10921 INDEX is the index 'i' of the element Ei to produce. ARGS,
10922 COMPLAIN, and IN_DECL are the same parameters as for the
10923 tsubst_pack_expansion function.
10925 The function returns the resulting Ei upon successful completion,
10926 or error_mark_node.
10928 Note that this function possibly modifies the ARGS parameter, so
10929 it's the responsibility of the caller to restore it. */
10931 static tree
10933 tree parm_packs,
10935 tree args /* This parm gets
10937 tsubst_flags_t complain,
10938 tree in_decl)
10939 {
10940 tree t;
10943 /* For each parameter pack, change the substitution of the parameter
10944 pack to the ith argument in its argument pack, then expand the
10945 pattern. */
10947 {
10952 ith_elem_is_expansion |=
10955 /* Select the Ith argument from the pack. */
10958 {
10960 {
10965 }
10966 else
10968 }
10969 else
10970 {
10975 {
10977 /* Update the corresponding argument. */
10979 }
10980 else
10981 /* Re-use the ARGUMENT_PACK_SELECT. */
10983 }
10985 }
10987 /* Substitute into the PATTERN with the (possibly altered)
10988 arguments. */
10990 /* Expanding a fixed parameter pack from
10991 coerce_template_parameter_pack. */
10996 {
10999 else
11002 }
11006 else
11009 /* If the Ith argument pack element is a pack expansion, then
11010 the Ith element resulting from the substituting is going to
11011 be a pack expansion as well. */
11016 }
11018 /* When the unexpanded parameter pack in a fold expression expands to an empty
11019 sequence, the value of the expression is as follows; the program is
11020 ill-formed if the operator is not listed in this table.
11022 && true
11023 || false
11024 , void() */
11026 tree
11028 {
11032 {
11041 }
11047 }
11049 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11050 form an expression that combines the two terms using the
11051 operator of T. */
11053 static tree
11055 {
11059 // Handle compound assignment operators.
11064 {
11074 complain);
11075 }
11076 }
11078 /* Substitute ARGS into the pack of a fold expression T. */
11082 {
11084 }
11086 /* Substitute ARGS into the pack of a fold expression T. */
11090 {
11092 }
11094 /* Expand a PACK of arguments into a grouped as left fold.
11095 Given a pack containing elements A0, A1, ..., An and an
11096 operator @, this builds the expression:
11098 ((A0 @ A1) @ A2) ... @ An
11100 Note that PACK must not be empty.
11102 The operator is defined by the original fold expression T. */
11104 static tree
11106 {
11109 {
11112 }
11114 }
11116 /* Substitute into a unary left fold expression. */
11118 static tree
11120 tree in_decl)
11121 {
11126 {
11130 }
11133 else
11135 }
11137 /* Substitute into a binary left fold expression.
11139 Do ths by building a single (non-empty) vector of argumnts and
11140 building the expression from those elements. */
11142 static tree
11144 tree in_decl)
11145 {
11154 {
11159 }
11167 }
11169 /* Expand a PACK of arguments into a grouped as right fold.
11170 Given a pack containing elementns A0, A1, ..., and an
11171 operator @, this builds the expression:
11173 A0@ ... (An-2 @ (An-1 @ An))
11175 Note that PACK must not be empty.
11177 The operator is defined by the original fold expression T. */
11179 tree
11181 {
11182 // Build the expression.
11186 {
11189 }
11191 }
11193 /* Substitute into a unary right fold expression. */
11195 static tree
11197 tree in_decl)
11198 {
11203 {
11207 }
11210 else
11212 }
11214 /* Substitute into a binary right fold expression.
11216 Do ths by building a single (non-empty) vector of arguments and
11217 building the expression from those elements. */
11219 static tree
11221 tree in_decl)
11222 {
11231 {
11236 }
11245 }
11248 /* Substitute ARGS into T, which is an pack expansion
11249 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11250 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11251 (if only a partial substitution could be performed) or
11252 ERROR_MARK_NODE if there was an error. */
11253 tree
11255 tree in_decl)
11256 {
11257 tree pattern;
11261 tree result;
11269 /* Add in any args remembered from an earlier partial instantiation. */
11274 /* Determine the argument packs that will instantiate the parameter
11275 packs used in the expansion expression. While we're at it,
11276 compute the number of arguments to be expanded and make sure it
11277 is consistent. */
11280 {
11287 {
11291 else
11294 }
11296 {
11297 /* We know we have correct local_specializations if this
11298 expansion is at function scope, or if we're dealing with a
11299 local parameter in a requires expression; for the latter,
11300 tsubst_requires_expr set it up appropriately. */
11303 else
11304 /* We can't rely on local_specializations for a parameter
11305 name used later in a function declaration (such as in a
11306 late-specified return type). Even if it exists, it might
11307 have the wrong value for a recursive call. */
11311 {
11312 /* This parameter pack was used in an unevaluated context. Just
11313 make a dummy decl, since it's only used for its type. */
11316 /* Partial instantiation of the parm_pack, we can't build
11317 up an argument pack yet. */
11319 else
11321 }
11322 }
11325 else
11326 {
11332 }
11339 /* This can only happen if we forget to expand an argument
11340 pack somewhere else. Just return an error, silently. */
11341 {
11345 }
11348 {
11352 /* Don't bother trying to do a partial substitution with
11353 incomplete packs; we'll try again after deduction. */
11360 {
11366 pattern);
11367 else
11370 pattern);
11372 }
11374 /* Keep track of the parameter packs and their corresponding
11375 argument packs. */
11378 }
11379 else
11380 {
11381 /* We can't substitute for this parameter pack. We use a flag as
11382 well as the missing_level counter because function parameter
11383 packs don't have a level. */
11386 }
11387 }
11389 /* If the expansion is just T..., return the matching argument pack, unless
11390 we need to call convert_from_reference on all the elements. This is an
11391 important optimization; see c++/68422. */
11394 {
11396 /* Types need no adjustment, nor does sizeof..., and if we still have
11397 some pack expansion args we won't do anything yet. */
11402 /* Also optimize expression pack expansions if we can tell that the
11403 elements won't have reference type. */
11409 /* Otherwise use the normal path so we get convert_from_reference. */
11410 }
11412 /* We cannot expand this expansion expression, because we don't have
11413 all of the argument packs we need. */
11415 {
11416 /* We got some full packs, but we can't substitute them in until we
11417 have values for all the packs. So remember these until then. */
11422 }
11424 {
11425 /* There were no real arguments, we're just replacing a parameter
11426 pack with another version of itself. Substitute into the
11427 pattern and return a PACK_EXPANSION_*. The caller will need to
11428 deal with that. */
11432 else
11436 }
11441 {
11442 /* We're in a late-specified return type, so create our own local
11443 specializations map; the current map is either NULL or (in the
11444 case of recursive unification) might have bindings that we don't
11445 want to use or alter. */
11448 }
11450 /* For each argument in each argument pack, substitute into the
11451 pattern. */
11455 {
11457 i,
11459 in_decl);
11462 {
11465 }
11466 }
11468 /* Update ARGS to restore the substitution from parameter packs to
11469 their argument packs. */
11471 {
11477 else
11478 {
11486 /* Update the corresponding argument. */
11490 else
11492 }
11493 }
11496 {
11499 }
11501 /* If the dependent pack arguments were such that we end up with only a
11502 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11508 }
11510 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11511 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11512 parameter packs; all parms generated from a function parameter pack will
11513 have the same DECL_PARM_INDEX. */
11515 tree
11517 {
11519 tree patparm;
11522 {
11528 }
11529 else
11530 {
11535 }
11538 }
11540 /* Make an argument pack out of the TREE_VEC VEC. */
11542 static tree
11544 {
11545 tree pack;
11549 else
11550 {
11554 }
11557 }
11559 /* Return an exact copy of template args T that can be modified
11560 independently. */
11562 static tree
11564 {
11572 {
11577 }
11583 }
11585 /* Substitute ARGS into the vector or list of template arguments T. */
11587 static tree
11589 {
11601 {
11603 tree new_arg;
11608 {
11609 /* Substitute into an expansion expression. */
11613 /* Add to the expanded length adjustment the number of
11614 expanded arguments. We subtract one from this
11615 measurement, because the argument pack expression
11616 itself is already counted as 1 in
11617 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11618 the argument pack is empty. */
11620 }
11622 {
11623 /* Substitute into each of the arguments. */
11629 new_arg,
11643 }
11644 }
11645 else
11654 }
11659 /* Make space for the expanded arguments coming from template
11660 argument packs. */
11662 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11663 arguments for a member template.
11664 In that case each TREE_VEC in ORIG_T represents a level of template
11665 arguments, and ORIG_T won't carry any non defaulted argument count.
11666 It will rather be the nested TREE_VECs that will carry one.
11667 In other words, ORIG_T carries a non defaulted argument count only
11668 if it doesn't contain any nested TREE_VEC. */
11670 {
11674 }
11676 {
11680 {
11683 /* Now expand the template argument pack "in place". */
11686 }
11687 else
11688 {
11690 out++;
11691 }
11692 }
11695 }
11697 /* Substitute ARGS into one level PARMS of template parameters. */
11699 static tree
11701 {
11708 {
11716 }
11719 }
11721 /* Return the result of substituting ARGS into the template parameters
11722 given by PARMS. If there are m levels of ARGS and m + n levels of
11723 PARMS, then the result will contain n levels of PARMS. For
11724 example, if PARMS is `template <class T> template <class U>
11725 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11726 result will be `template <int*, double, class V>'. */
11728 static tree
11730 {
11734 /* When substituting into a template, we must set
11735 PROCESSING_TEMPLATE_DECL as the template parameters may be
11736 dependent if they are based on one-another, and the dependency
11737 predicates are short-circuit outside of templates. */
11744 {
11751 }
11756 }
11758 /* Return the result of substituting ARGS into one template parameter
11759 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11760 parameter and which TREE_PURPOSE is the default argument of the
11761 template parameter. */
11763 static tree
11765 {
11786 }
11788 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11789 type T. If T is not an aggregate or enumeration type, it is
11790 handled as if by tsubst. IN_DECL is as for tsubst. If
11791 ENTERING_SCOPE is nonzero, T is the context for a template which
11792 we are presently tsubst'ing. Return the substituted value. */
11794 static tree
11796 tree args,
11797 tsubst_flags_t complain,
11798 tree in_decl,
11800 {
11805 {
11810 /* Fall through. */
11814 {
11815 tree argvec;
11816 tree context;
11817 tree r;
11821 /* In "sizeof(X<I>)" we need to evaluate "I". */
11827 /* First, determine the context for the type we are looking
11828 up. */
11831 {
11834 /* If context is a nested class inside a class template,
11835 it may still need to be instantiated (c++/33959). */
11837 }
11839 /* Then, figure out what arguments are appropriate for the
11840 type we are trying to find. For example, given:
11842 template <class T> struct S;
11843 template <class T, class U> void f(T, U) { S<U> su; }
11845 and supposing that we are instantiating f<int, double>,
11846 then our ARGS will be {int, double}, but, when looking up
11847 S we only want {double}. */
11852 else
11853 {
11857 }
11863 }
11864 else
11865 /* This is not a template type, so there's nothing to do. */
11870 }
11871 }
11873 /* Substitute into the default argument ARG (a default argument for
11874 FN), which has the indicated TYPE. */
11876 tree
11878 {
11883 /* This can happen in invalid code. */
11887 /* This default argument came from a template. Instantiate the
11888 default argument here, not in tsubst. In the case of
11889 something like:
11891 template <class T>
11892 struct S {
11893 static T t();
11894 void f(T = t());
11895 };
11897 we must be careful to do name lookup in the scope of S<T>,
11898 rather than in the current class. */
11900 /* The "this" pointer is not valid in a default argument. */
11902 {
11907 }
11910 /* The default argument expression may cause implicitly defined
11911 member functions to be synthesized, which will result in garbage
11912 collection. We must treat this situation as if we were within
11913 the body of function so as to avoid collecting live data on the
11914 stack. */
11922 /* Restore the "this" pointer. */
11924 {
11927 }
11934 /* Make sure the default argument is reasonable. */
11940 }
11942 /* Substitute into all the default arguments for FN. */
11944 static void
11946 {
11947 tree arg;
11948 tree tmpl_args;
11952 /* If this function is not yet instantiated, we certainly don't need
11953 its default arguments. */
11956 /* Don't do this again for clones. */
11961 arg;
11967 complain);
11968 }
11970 /* Substitute the ARGS into the T, which is a _DECL. Return the
11971 result of the substitution. Issue error and warning messages under
11972 control of COMPLAIN. */
11974 static tree
11976 {
11977 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
11978 location_t saved_loc;
11983 /* Set the filename and linenumber to improve error-reporting. */
11988 {
11990 {
11991 /* We can get here when processing a member function template,
11992 member class template, or template template parameter. */
11994 tree spec;
11995 tree tmpl_args;
11996 tree full_args;
11999 {
12000 /* Template template parameter is treated here. */
12004 /* If we get a real template back, return it. This can happen in
12005 the context of most_specialized_partial_spec. */
12008 else
12009 /* The new TEMPLATE_DECL was built in
12010 reduce_template_parm_level. */
12013 }
12015 /* We might already have an instance of this template.
12016 The ARGS are for the surrounding class type, so the
12017 full args contain the tsubst'd args for the context,
12018 plus the innermost args from the template decl. */
12022 /* Because this is a template, the arguments will still be
12023 dependent, even after substitution. If
12024 PROCESSING_TEMPLATE_DECL is not set, the dependency
12025 predicates will short-circuit. */
12033 /* If this is a default template template argument,
12034 tsubst might not have changed anything. */
12041 {
12044 }
12046 /* Make a new template decl. It will be similar to the
12047 original, but will record the current template arguments.
12048 We also create a new function declaration, which is just
12049 like the old one, but points to this new template, rather
12050 than the old one. */
12055 // Build new template info linking to the original template decl.
12060 {
12061 tree new_type;
12069 /* For a partial specialization, we need to keep pointing to
12070 the primary template. */
12076 }
12077 else
12078 {
12079 tree new_decl;
12091 }
12097 /* The template parameters for this new template are all the
12098 template parameters for the old template, except the
12099 outermost level of parameters. */
12102 complain);
12108 /* Record this non-type partial instantiation. */
12112 }
12116 {
12117 tree ctx;
12120 tree gen_tmpl;
12121 tree type;
12126 /* Nobody should be tsubst'ing into non-template functions. */
12130 {
12131 tree spec;
12133 /* If T is not dependent, just return it. */
12137 /* Calculate the most general template of which R is a
12138 specialization, and the complete set of arguments used to
12139 specialize R. */
12142 (DECL_TEMPLATE_RESULT
12148 /* Check to see if we already have this specialization. */
12153 {
12156 }
12158 /* We can see more levels of arguments than parameters if
12159 there was a specialization of a member template, like
12160 this:
12162 template <class T> struct S { template <class U> void f(); }
12163 template <> template <class U> void S<int>::f(U);
12165 Here, we'll be substituting into the specialization,
12166 because that's where we can find the code we actually
12167 want to generate, but we'll have enough arguments for
12168 the most general template.
12170 We also deal with the peculiar case:
12172 template <class T> struct S {
12173 template <class U> friend void f();
12174 };
12175 template <class U> void f() {}
12176 template S<int>;
12177 template void f<double>();
12179 Here, the ARGS for the instantiation of will be {int,
12180 double}. But, we only need as many ARGS as there are
12181 levels of template parameters in CODE_PATTERN. We are
12182 careful not to get fooled into reducing the ARGS in
12183 situations like:
12185 template <class T> struct S { template <class U> void f(U); }
12186 template <class T> template <> void S<T>::f(int) {}
12188 which we can spot because the pattern will be a
12189 specialization in this case. */
12191 parms_depth =
12196 }
12197 else
12198 {
12199 /* This special case arises when we have something like this:
12201 template <class T> struct S {
12202 friend void f<int>(int, double);
12203 };
12205 Here, the DECL_TI_TEMPLATE for the friend declaration
12206 will be an IDENTIFIER_NODE. We are being called from
12207 tsubst_friend_function, and we want only to create a
12208 new decl (R) with appropriate types so that we can call
12209 determine_specialization. */
12211 }
12214 {
12217 else
12221 }
12222 else
12223 {
12226 }
12231 /* If we hit excessive deduction depth, the type is bogus even if
12232 it isn't error_mark_node, so don't build a decl. */
12236 /* We do NOT check for matching decls pushed separately at this
12237 point, as they may not represent instantiations of this
12238 template, and in any case are considered separate under the
12239 discrete model. */
12243 /* Clear out the mangled name and RTL for the instantiation. */
12246 /* Leave DECL_INITIAL set on deleted instantiations. */
12251 /* OpenMP UDRs have the only argument a reference to the declared
12252 type. We want to diagnose if the declared type is a reference,
12253 which is invalid, but as references to references are usually
12254 quietly merged, diagnose it here. */
12256 {
12257 tree argtype
12262 "reference type %qT in "
12266 argtype);
12267 }
12270 /* Type-conversion operator. Reconstruct the name, in
12271 case it's the name of one of the template's parameters. */
12281 /* If this is an instantiation of a function with internal
12282 linkage, we already know what object file linkage will be
12283 assigned to the instantiation. */
12292 /* We'll re-clone as appropriate in instantiate_template. */
12295 /* If we aren't complaining now, return on error before we register
12296 the specialization so that we'll complain eventually. */
12302 /* When instantiating a constrained member, substitute
12303 into the constraints to create a new constraint. */
12306 {
12309 }
12311 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12312 this in the special friend case mentioned above where
12313 GEN_TMPL is NULL. */
12315 {
12320 tree new_r
12323 /* We instantiated this while substituting into
12324 the type earlier (template/friend54.C). */
12327 /* We're not supposed to instantiate default arguments
12328 until they are called, for a template. But, for a
12329 declaration like:
12331 template <class T> void f ()
12332 { extern void g(int i = T()); }
12334 we should do the substitution when the template is
12335 instantiated. We handle the member function case in
12336 instantiate_class_template since the default arguments
12337 might refer to other members of the class. */
12342 }
12343 else
12346 /* Copy the list of befriending classes. */
12350 {
12354 in_decl);
12355 }
12358 {
12362 /* If this is an instantiation of a member template, clone it.
12363 If it isn't, that'll be handled by
12364 clone_constructors_and_destructors. */
12367 }
12378 /* Possibly limit visibility based on template args. */
12381 {
12385 }
12393 }
12397 {
12405 {
12406 /* If there is a local specialization that isn't a
12407 parameter pack, it means that we're doing a "simple"
12408 substitution from inside tsubst_pack_expansion. Just
12409 return the local specialization (which will be a single
12410 parm). */
12417 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12418 the parameters in this function parameter pack. */
12422 {
12425 /* Zero-length parameter packs are boring. Just substitute
12426 into the chain. */
12430 }
12431 else
12432 {
12433 /* All we did was update the type. Make a note of that. */
12436 }
12437 }
12439 /* Loop through all of the parameters we'll build. When T is
12440 a function parameter pack, LEN is the number of expanded
12441 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12444 {
12451 /* We're on the Ith parameter of the function parameter
12452 pack. */
12453 {
12454 /* Get the Ith type. */
12457 /* Rename the parameter to include the index. */
12460 }
12462 /* We're dealing with a normal parameter. */
12470 {
12473 else
12476 }
12486 /* Keep track of the first new parameter we
12487 generate. That's what will be returned to the
12488 caller. */
12492 /* Build a proper chain of parameters when substituting
12493 into a function parameter pack. */
12496 }
12498 /* If cp_unevaluated_operand is set, we're just looking for a
12499 single dummy parameter, so don't keep going. */
12504 /* FIRST_R contains the start of the chain we've built. */
12506 }
12510 {
12517 {
12518 /* This field is a lambda capture pack. Return a TREE_VEC of
12519 the expanded fields to instantiate_class_template_1 and
12520 store them in the specializations hash table as a
12521 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12525 {
12528 }
12529 else
12530 {
12531 /* All we did was update the type. Make a note of that. */
12534 }
12535 }
12538 {
12541 {
12545 }
12555 /* For bit-fields, DECL_INITIAL gives the number of bits. For
12556 non-bit-fields DECL_INITIAL is a non-static data member
12557 initializer, which gets deferred instantiation. */
12563 {
12564 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12565 NSDMI in perform_member_init. Still set DECL_INITIAL
12566 so that we know there is one. */
12571 }
12572 /* We don't have to set DECL_CONTEXT here; it is set by
12573 finish_member_declaration. */
12581 }
12584 {
12592 }
12593 }
12597 /* We reach here only for member using decls. We also need to check
12598 uses_template_parms because DECL_DEPENDENT_P is not set for a
12599 using-declaration that designates a member of the current
12600 instantiation (c++/53549). */
12603 {
12607 {
12612 {
12616 {
12619 }
12620 else
12621 {
12624 }
12626 }
12627 }
12628 else
12629 {
12635 else
12636 {
12639 }
12640 }
12641 }
12642 else
12643 {
12646 }
12651 {
12654 tree spec;
12656 tree ctx;
12665 {
12666 /* If this is the canonical decl, we don't have to
12667 mess with instantiations, and often we can't (for
12668 typename, template type parms and such). Note that
12669 TYPE_NAME is not correct for the above test if
12670 we've copied the type for a typedef. */
12676 }
12678 /* Check to see if we already have the specialization we
12679 need. */
12682 {
12683 /* T is a static data member or namespace-scope entity.
12684 We have to substitute into namespace-scope variables
12685 (not just variable templates) because of cases like:
12687 template <class T> void f() { extern T t; }
12689 where the entity referenced is not known until
12690 instantiation time. */
12694 {
12696 complain,
12698 /* If CTX is unchanged, then T is in fact the
12699 specialization we want. That situation occurs when
12700 referencing a static data member within in its own
12701 class. We can use pointer equality, rather than
12702 same_type_p, because DECL_CONTEXT is always
12703 canonical... */
12705 /* ... unless T is a member template; in which
12706 case our caller can be willing to create a
12707 specialization of that template represented
12708 by T. */
12712 }
12715 {
12720 argvec = (coerce_innermost_template_parms
12728 }
12729 }
12730 else
12731 {
12732 /* A local variable. */
12734 /* Subsequent calls to pushdecl will fill this in. */
12736 /* Unless this is a reference to a static variable from an
12737 enclosing function, in which case we need to fill it in now. */
12739 {
12743 }
12745 }
12746 /* If we already have the specialization we need, there is
12747 nothing more to do. */
12749 {
12752 }
12754 /* Create a new node for the specialization we need. */
12757 {
12760 else
12767 }
12769 {
12770 /* Even if the original location is out of scope, the
12771 newly substituted one is not. */
12778 {
12779 /* It may seem that this case cannot occur, since:
12781 typedef void f();
12782 void g() { f x; }
12784 declares a function, not a variable. However:
12786 typedef void f();
12787 template <typename T> void g() { T t; }
12788 template void g<f>();
12790 is an attempt to declare a variable with function
12791 type. */
12793 /* R is not yet sufficiently initialized, so we
12794 just use its name. */
12797 }
12799 /* Wait until cp_finish_decl to set this again, to handle
12800 circular dependency (template/instantiate6.C). */
12805 {
12810 {
12813 }
12815 }
12819 }
12825 /* Clear out the mangled name and RTL for the instantiation. */
12829 /* The initializer must not be expanded until it is required;
12830 see [temp.inst]. */
12838 {
12839 /* Possibly limit visibility based on template args. */
12842 {
12846 }
12848 }
12851 {
12852 /* A static data member declaration is always marked
12853 external when it is declared in-class, even if an
12854 initializer is present. We mimic the non-template
12855 processing here. */
12863 }
12864 else
12865 {
12870 }
12878 /* Preserve a typedef that names a type. */
12880 {
12884 /* An alias template specialization can be dependent
12885 even if its underlying type is not. */
12887 }
12890 }
12895 }
12896 #undef RETURN
12898 out:
12899 /* Restore the file and line information. */
12903 }
12905 /* Substitute into the ARG_TYPES of a function type.
12906 If END is a TREE_CHAIN, leave it and any following types
12907 un-substituted. */
12909 static tree
12911 tree args,
12912 tree end,
12913 tsubst_flags_t complain,
12914 tree in_decl)
12915 {
12916 tree remaining_arg_types;
12920 tree default_arg;
12931 {
12932 /* For a pack expansion, perform substitution on the
12933 entire expression. Later on, we'll handle the arguments
12934 one-by-one. */
12939 /* So that we'll spin through the parameters, one by one. */
12941 else
12942 {
12943 /* We only partially substituted into the parameter
12944 pack. Our type is TYPE_PACK_EXPANSION. */
12947 }
12948 }
12961 {
12963 {
12967 }
12969 }
12970 /* DR 657. */
12974 /* Do array-to-pointer, function-to-pointer conversion, and ignore
12975 top-level qualifiers as required. */
12978 /* We do not substitute into default arguments here. The standard
12979 mandates that they be instantiated only when needed, which is
12980 done in build_over_call. */
12984 {
12985 /* We've instantiated a template before its default arguments
12986 have been parsed. This can happen for a nested template
12987 class, and is not an error unless we require the default
12988 argument in a call of this function. */
12989 remaining_arg_types =
12992 }
12993 else
12994 remaining_arg_types =
12996 }
12999 }
13001 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13002 *not* handle the exception-specification for FNTYPE, because the
13003 initial substitution of explicitly provided template parameters
13004 during argument deduction forbids substitution into the
13005 exception-specification:
13007 [temp.deduct]
13009 All references in the function type of the function template to the
13010 corresponding template parameters are replaced by the specified tem-
13011 plate argument values. If a substitution in a template parameter or
13012 in the function type of the function template results in an invalid
13013 type, type deduction fails. [Note: The equivalent substitution in
13014 exception specifications is done only when the function is instanti-
13015 ated, at which point a program is ill-formed if the substitution
13016 results in an invalid type.] */
13018 static tree
13020 tree args,
13021 tsubst_flags_t complain,
13022 tree in_decl)
13023 {
13024 tree return_type;
13026 tree fntype;
13028 /* The TYPE_CONTEXT is not used for function/method types. */
13031 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13032 failure. */
13036 {
13037 /* Substitute the argument types. */
13049 {
13050 /* DR 1207: 'this' is in scope in the trailing return type. */
13052 }
13054 /* Substitute the return type. */
13058 {
13061 }
13062 }
13063 else
13064 /* Substitute the return type. */
13069 /* DR 486 clarifies that creation of a function type with an
13070 invalid return type is a deduction failure. */
13073 {
13075 {
13078 else
13080 }
13082 }
13083 /* And DR 657. */
13088 {
13089 /* Substitute the argument types. */
13094 }
13096 /* Construct a new type node and return it. */
13098 {
13103 }
13104 else
13105 {
13107 /* Don't pick up extra function qualifiers from the basetype. */
13110 {
13111 /* [temp.deduct]
13113 Type deduction may fail for any of the following
13114 reasons:
13116 -- Attempting to create "pointer to member of T" when T
13117 is not a class type. */
13120 r);
13122 }
13127 }
13134 }
13136 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13137 ARGS into that specification, and return the substituted
13138 specification. If there is no specification, return NULL_TREE. */
13140 static tree
13142 tree args,
13143 tsubst_flags_t complain,
13144 tree in_decl,
13146 {
13147 tree specs;
13148 tree new_specs;
13153 {
13154 /* A noexcept-specifier. */
13159 {
13160 /* Defer instantiation of noexcept-specifiers to avoid
13161 excessive instantiations (c++/49107). */
13164 {
13165 /* We already partially instantiated this member template,
13166 so combine the new args with the old. */
13171 }
13172 else
13173 {
13176 }
13177 }
13178 else
13179 new_specs = tsubst_copy_and_build
13183 }
13185 {
13188 else
13190 {
13191 tree spec;
13196 {
13197 /* Expand the pack expansion type. */
13200 in_decl);
13206 else
13207 {
13208 /* We're substituting into a member template, so
13209 we got a TYPE_PACK_EXPANSION back. Add that
13210 expansion and move on. */
13214 expanded_specs,
13215 complain);
13218 }
13219 }
13222 {
13225 else
13230 complain);
13231 }
13234 }
13235 }
13237 }
13239 /* Take the tree structure T and replace template parameters used
13240 therein with the argument vector ARGS. IN_DECL is an associated
13241 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13242 Issue error and warning messages under control of COMPLAIN. Note
13243 that we must be relatively non-tolerant of extensions here, in
13244 order to preserve conformance; if we allow substitutions that
13245 should not be allowed, we may allow argument deductions that should
13246 not succeed, and therefore report ambiguous overload situations
13247 where there are none. In theory, we could allow the substitution,
13248 but indicate that it should have failed, and allow our caller to
13249 make sure that the right thing happens, but we don't try to do this
13250 yet.
13252 This function is used for dealing with types, decls and the like;
13253 for expressions, use tsubst_expr or tsubst_copy. */
13255 tree
13257 {
13280 else
13285 /* Reuse typedefs. We need to do this to handle dependent attributes,
13286 such as attribute aligned. */
13289 {
13293 {
13294 /* DECL represents an alias template and we want to
13295 instantiate it. */
13299 }
13303 {
13307 }
13312 else
13313 /* The typedef is from a non-template context. */
13317 {
13319 r = cp_build_qualified_type_real
13323 }
13324 else
13325 {
13326 /* We don't have an instantiation yet, so drop the typedef. */
13331 }
13332 }
13348 {
13374 {
13380 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13381 needed. */
13387 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13388 with TREE_SIDE_EFFECTS that indicates this is not an integral
13389 constant expression. */
13392 {
13395 }
13398 }
13404 {
13410 /* Early in template argument deduction substitution, we don't
13411 want to reduce the level of 'auto', or it will be confused
13412 with a normal template parm in subsequent deduction. */
13424 {
13428 {
13429 /* See through ARGUMENT_PACK_SELECT arguments. */
13431 /* If the selected argument is an expansion E, that most
13432 likely means we were called from
13433 gen_elem_of_pack_expansion_instantiation during the
13434 substituting of pack an argument pack (which Ith
13435 element is a pack expansion, where I is
13436 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13437 In this case, the Ith element resulting from this
13438 substituting is going to be a pack expansion, which
13439 pattern is the pattern of E. Let's return the
13440 pattern of E, and
13441 gen_elem_of_pack_expansion_instantiation will
13442 build the resulting pack expansion from it. */
13444 {
13445 /* Make sure we aren't throwing away arg info. */
13448 }
13449 }
13450 }
13455 {
13457 /* If ARG is an argument pack, we don't actually want to
13458 perform a substitution here, because substitutions
13459 for argument packs are only done
13460 element-by-element. We can get to this point when
13461 substituting the type of a non-type template
13462 parameter pack, when that type actually contains
13463 template parameter packs from an outer template, e.g.,
13465 template<typename... Types> struct A {
13466 template<Types... Values> struct B { };
13467 }; */
13471 {
13477 return cp_build_qualified_type_real
13479 }
13481 {
13482 /* We are processing a type constructed from a
13483 template template parameter. */
13494 /* Consider this code:
13496 template <template <class> class Template>
13497 struct Internal {
13498 template <class Arg> using Bind = Template<Arg>;
13499 };
13501 template <template <class> class Template, class Arg>
13502 using Instantiate = Template<Arg>; //#0
13504 template <template <class> class Template,
13505 class Argument>
13506 using Bind =
13507 Instantiate<Internal<Template>::template Bind,
13508 Argument>; //#1
13510 When #1 is parsed, the
13511 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13512 parameter `Template' in #0 matches the
13513 UNBOUND_CLASS_TEMPLATE representing the argument
13514 `Internal<Template>::template Bind'; We then want
13515 to assemble the type `Bind<Argument>' that can't
13516 be fully created right now, because
13517 `Internal<Template>' not being complete, the Bind
13518 template cannot be looked up in that context. So
13519 we need to "store" `Bind<Argument>' for later
13520 when the context of Bind becomes complete. Let's
13521 store that in a TYPENAME_TYPE. */
13525 argvec),
13526 typename_type,
13527 complain);
13529 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13530 are resolving nested-types in the signature of a
13531 member function templates. Otherwise ARG is a
13532 TEMPLATE_DECL and is the real template to be
13533 instantiated. */
13541 complain);
13542 return cp_build_qualified_type_real
13544 }
13547 else
13548 /* TEMPLATE_PARM_INDEX. */
13550 }
13553 /* This can happen during the attempted tsubst'ing in
13554 unify. This means that we don't yet have any information
13555 about the template parameter in question. */
13558 /* If we get here, we must have been looking at a parm for a
13559 more deeply nested template. Make a new version of this
13560 template parameter, but with a lower level. */
13562 {
13567 {
13569 r = cp_build_qualified_type_real
13573 }
13580 /* Break infinite recursion when substituting the constraints
13582 else
13583 {
13594 {
13595 /* Propagate constraints on placeholders. */
13600 {
13604 }
13605 }
13608 /* We have reduced the level of the template
13609 template parameter, but not the levels of its
13610 template parameters, so canonical_type_parameter
13611 will not be able to find the canonical template
13612 template parameter for this level. Thus, we
13613 require structural equality checking to compare
13614 TEMPLATE_TEMPLATE_PARMs. */
13618 else
13622 {
13624 /* We might need to substitute into the types of non-type
13625 template parameters. */
13637 }
13638 }
13647 }
13650 }
13653 {
13661 {
13665 }
13668 {
13672 }
13675 {
13679 }
13685 }
13688 /* We should never be tsubsting a binfo. */
13692 /* A vector of template arguments. */
13698 {
13702 /* [temp.deduct]
13704 Type deduction may fail for any of the following
13705 reasons:
13707 -- Attempting to create a pointer to reference type.
13708 -- Attempting to create a reference to a reference type or
13709 a reference to void.
13711 Core issue 106 says that creating a reference to a reference
13712 during instantiation is no longer a cause for failure. We
13713 only enforce this check in strict C++98 mode. */
13717 {
13720 /* We keep track of the last time we issued this error
13721 message to avoid spewing a ton of messages during a
13722 single bad template instantiation. */
13725 {
13730 else
13733 }
13736 }
13740 {
13742 {
13745 type);
13746 else
13748 type);
13749 }
13751 }
13753 {
13757 }
13759 /* In C++0x, during template argument substitution, when there is an
13760 attempt to create a reference to a reference type, reference
13761 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13763 "If a template-argument for a template-parameter T names a type
13764 that is a reference to a type A, an attempt to create the type
13765 'lvalue reference to cv T' creates the type 'lvalue reference to
13766 A,' while an attempt to create the type type rvalue reference to
13767 cv T' creates the type T"
13768 */
13769 r = cp_build_reference_type
13772 else
13777 /* Will this ever be needed for TYPE_..._TO values? */
13781 }
13783 {
13786 {
13787 /* [temp.deduct]
13789 Type deduction may fail for any of the following
13790 reasons:
13792 -- Attempting to create "pointer to member of T" when T
13793 is not a class type. */
13797 }
13799 {
13803 }
13805 {
13809 }
13812 {
13813 /* The type of the implicit object parameter gets its
13814 cv-qualifiers from the FUNCTION_TYPE. */
13815 tree memptr;
13816 tree method_type
13821 complain);
13822 }
13823 else
13826 complain);
13827 }
13830 {
13831 tree fntype;
13832 tree specs;
13837 /* Substitute the exception specification. */
13845 }
13847 {
13852 /* As an optimization, we avoid regenerating the array type if
13853 it will obviously be the same as T. */
13857 /* These checks should match the ones in create_array_type_for_decl.
13859 [temp.deduct]
13861 The deduction may fail for any of the following reasons:
13863 -- Attempting to create an array with an element type that
13864 is void, a function type, or a reference type, or [DR337]
13865 an abstract class type. */
13871 {
13875 }
13883 {
13886 }
13889 }
13892 {
13904 {
13908 }
13910 {
13911 /* Normally, make_typename_type does not require that the CTX
13912 have complete type in order to allow things like:
13914 template <class T> struct S { typename S<T>::X Y; };
13916 But, such constructs have already been resolved by this
13917 point, so here CTX really should have complete type, unless
13918 it's a partial instantiation. */
13921 {
13925 }
13926 }
13933 {
13936 }
13939 {
13941 {
13945 else
13947 }
13949 {
13953 else
13955 }
13956 }
13958 return cp_build_qualified_type_real
13960 }
13963 {
13975 }
13978 {
13979 tree type;
13995 complain);
13996 }
13999 {
14000 tree type;
14011 {
14013 {
14017 }
14020 }
14031 else
14032 {
14036 /* In a template ~id could be either a complement expression
14037 or an unqualified-id naming a destructor; if instantiating
14038 it produces an expression, it's not an id-expression or
14039 member access. */
14042 }
14047 }
14050 {
14054 }
14058 {
14059 tree r;
14062 {
14064 /* Set the already-substituted type. */
14066 }
14067 else
14075 }
14090 /* We should use one of the expression tsubsts for these codes. */
14096 }
14097 }
14099 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
14100 type of the expression on the left-hand side of the "." or "->"
14101 operator. */
14103 static tree
14106 {
14107 tree name;
14108 tree qualifying_scope;
14109 tree fns;
14110 tree optype;
14115 /* A baselink indicates a function from a base class. Both the
14116 BASELINK_ACCESS_BINFO and the base class referenced may
14117 indicate bases of the template class, rather than the
14118 instantiated class. In addition, lookups that were not
14119 ambiguous before may be ambiguous now. Therefore, we perform
14120 the lookup again. */
14127 {
14134 }
14140 {
14142 {
14146 }
14148 }
14150 /* If lookup found a single function, mark it as used at this
14151 point. (If it lookup found multiple functions the one selected
14152 later by overload resolution will be marked as used at that
14153 point.) */
14160 /* Add back the template arguments, if present. */
14164 unknown_type_node,
14166 template_args);
14167 /* Update the conversion operator type. */
14175 {
14177 qualifying_scope,
14178 object_type);
14180 /* We need to call adjust_result_of_qualified_name_lookup in case the
14181 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14182 so that we still get virtual function binding. */
14184 }
14186 }
14188 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14189 true if the qualified-id will be a postfix-expression in-and-of
14190 itself; false if more of the postfix-expression follows the
14191 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14192 of "&". */
14194 static tree
14198 {
14199 tree expr;
14200 tree scope;
14201 tree name;
14203 tree template_args;
14208 /* Figure out what name to look up. */
14211 {
14221 }
14222 else
14223 {
14226 }
14228 /* Substitute into the qualifying scope. When there are no ARGS, we
14229 are just trying to simplify a non-dependent expression. In that
14230 case the qualifying scope may be dependent, and, in any case,
14231 substituting will not help. */
14234 {
14237 }
14238 else
14242 {
14249 }
14252 {
14254 {
14255 /* A BIT_NOT_EXPR is used to represent a destructor. */
14257 {
14261 }
14262 else
14265 }
14266 else
14270 {
14272 {
14276 }
14278 }
14279 }
14282 {
14284 scope);
14285 /* Remember that there was a reference to this entity. */
14288 }
14291 {
14297 }
14300 {
14303 complain);
14304 else
14306 }
14312 {
14313 expr = (adjust_result_of_qualified_name_lookup
14315 expr = (finish_qualified_id_expr
14319 }
14321 /* Expressions do not generally have reference type. */
14323 /* However, if we're about to form a pointer-to-member, we just
14324 want the referenced member referenced. */
14332 }
14334 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14335 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14336 for tsubst. */
14338 static tree
14341 {
14348 {
14349 /* If we had an initializer but it
14350 instantiated to nothing,
14351 value-initialize the object. This will
14352 only occur when the initializer was a
14353 pack expansion where the parameter packs
14354 used in that expansion were of length
14355 zero. */
14357 complain);
14360 }
14363 }
14365 /* Like tsubst, but deals with expressions. This function just replaces
14366 template parms; to finish processing the resultant expression, use
14367 tsubst_copy_and_build or tsubst_expr. */
14369 static tree
14371 {
14373 tree r;
14381 {
14386 {
14387 /* We get here for a use of 'this' in an NSDMI as part of a
14388 constructor call or as part of an aggregate initialization. */
14390 && ((current_function_decl
14392 || (current_class_ref
14396 /* This can happen for a parameter name used later in a function
14397 declaration (such as in a late-specified return type). Just
14398 make a dummy decl, since it's only used for its type. */
14401 /* Give it the template pattern as its context; its true context
14402 hasn't been instantiated yet and this is good enough for
14403 mangling. */
14405 }
14414 {
14415 tree enum_type;
14416 tree v;
14420 /* There is no need to substitute into namespace-scope
14421 enumerators. */
14424 /* If ARGS is NULL, then T is known to be non-dependent. */
14428 /* Unfortunately, we cannot just call lookup_name here.
14429 Consider:
14431 template <int I> int f() {
14432 enum E { a = I };
14433 struct S { void g() { E e = a; } };
14434 };
14436 When we instantiate f<7>::S::g(), say, lookup_name is not
14437 clever enough to find f<7>::a. */
14438 enum_type
14448 /* We didn't find the name. That should never happen; if
14449 name-lookup found it during preliminary parsing, we
14450 should find it again here during instantiation. */
14452 }
14457 {
14458 /* Check for a local specialization set up by
14459 tsubst_pack_expansion. */
14461 {
14465 }
14467 /* When retrieving a capture pack from a generic lambda, remove the
14468 lambda call op's own template argument list from ARGS. Only the
14469 template arguments active for the closure type should be used to
14470 retrieve the pack specialization. */
14476 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14477 tsubst_decl put in the hash table. */
14479 }
14482 {
14483 tree ctx;
14488 {
14491 {
14495 }
14497 }
14498 }
14508 {
14511 {
14512 /* First try name lookup to find the instantiation. */
14515 {
14516 /* Make sure that the one we found is the one we want. */
14522 }
14526 else
14527 {
14528 /* This can happen for a variable used in a
14529 late-specified return type of a local lambda, or for a
14530 local static or constant. Building a new VAR_DECL
14531 should be OK in all those cases. */
14534 {
14535 /* We can't call cp_finish_decl, so handle the
14536 initializer by hand. */
14547 }
14554 }
14555 /* Remember this for subsequent uses. */
14558 }
14559 }
14560 else
14570 /* An OVERLOAD will always be a non-dependent overload set; an
14571 overload set from function scope will just be represented with an
14572 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14588 {
14589 /* Template template argument like the following example need
14590 special treatment:
14592 template <template <class> class TT> struct C {};
14593 template <class T> struct D {
14594 template <class U> struct E {};
14595 C<E> c; // #1
14596 };
14597 D<int> d; // #2
14599 We are processing the template argument `E' in #1 for
14600 the template instantiation #2. Originally, `E' is a
14601 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14602 have to substitute this with one having context `D<int>'. */
14606 }
14607 else
14608 /* Ordinary template template argument. */
14619 {
14623 }
14628 {
14637 /* We only want to compute the number of arguments. */
14640 else
14647 {
14649 /* Set TREE_USED for the benefit of -Wunused. */
14653 }
14661 {
14666 else
14672 else
14675 }
14676 else
14678 }
14680 {
14688 }
14689 /* Fall through */
14705 {
14709 }
14712 {
14713 tree object;
14714 tree name;
14719 {
14723 }
14726 {
14736 }
14741 in_decl);
14742 else
14745 }
14783 {
14787 }
14790 {
14795 }
14798 {
14802 }
14805 {
14813 }
14819 {
14826 }
14829 {
14836 }
14839 {
14846 }
14849 {
14850 /* Substituted template arguments */
14859 }
14862 {
14882 }
14907 /* Fall through. */
14910 {
14913 }
14914 else
14918 /* This is handled by tsubst_copy_and_build. */
14922 {
14926 }
14929 /* We shouldn't have built any of these during initial template
14930 generation. Instead, they should be built during instantiation
14931 in response to the saved STMT_IS_FULL_EXPR_P setting. */
14935 {
14945 }
14963 {
14964 /* Instantiate any typedefs in the type. */
14969 }
14972 /* These can sometimes show up in a partial instantiation, but never
14973 involve template parms. */
14987 /* We shouldn't get here, but keep going if !flag_checking. */
14991 }
14992 }
14994 /* Helper function for tsubst_omp_clauses, used for instantiation of
14995 OMP_CLAUSE_DECL of clauses. */
14997 static tree
14999 tree in_decl)
15000 {
15004 /* Handle an OpenMP array section represented as a TREE_LIST (or
15005 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15006 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15007 TREE_LIST. We can handle it exactly the same as an array section
15008 (purpose, value, and a chain), even though the nomenclature
15009 (low_bound, length, etc) is different. */
15011 {
15012 tree low_bound
15018 in_decl);
15027 }
15030 /* Undo convert_from_reference tsubst_expr could have called. */
15036 }
15038 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15040 static tree
15043 {
15048 {
15054 {
15057 {
15063 }
15064 /* FALLTHRU */
15079 in_decl);
15110 {
15113 {
15120 }
15121 else
15123 }
15126 in_decl);
15132 in_decl);
15140 in_decl);
15142 {
15145 }
15150 else
15153 in_decl,
15176 {
15180 loc;
15182 {
15185 }
15186 }
15190 }
15193 {
15203 /* tsubst_expr on SCOPE_REF results in returning
15204 finish_non_static_data_member result. Undo that here. */
15208 {
15213 {
15217 CASE_CONVERT:
15226 /* FALLTHRU */
15230 }
15231 }
15237 {
15240 {
15244 }
15245 }
15249 }
15250 }
15254 {
15259 {
15262 }
15263 }
15265 }
15267 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15269 static tree
15271 tree in_decl)
15272 {
15273 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15293 {
15296 else
15297 {
15301 }
15302 }
15307 #undef RECUR
15308 }
15310 /* Used to temporarily communicate the list of #pragma omp parallel
15311 clauses to #pragma omp for instantiation if they are combined
15312 together. */
15316 /* Substitute one OMP_FOR iterator. */
15318 static void
15323 {
15324 #define RECUR(NODE) \
15325 tsubst_expr ((NODE), args, complain, in_decl, \
15326 integral_constant_expression_p)
15333 {
15336 }
15342 {
15343 /* We need to jump through some hoops to handle declarations in the
15344 init-statement, since we might need to handle auto deduction,
15345 but we need to keep control of initialization. */
15349 }
15350 else
15351 {
15353 {
15356 {
15360 {
15364 CASE_CONVERT:
15372 {
15375 }
15376 /* FALLTHRU */
15380 }
15381 }
15382 }
15383 else
15385 }
15396 {
15398 {
15399 /* Declare the variable, but don't let that initialize it. */
15404 }
15409 {
15414 }
15415 else
15422 }
15425 {
15426 /* Declare and initialize the variable. */
15429 }
15431 {
15435 {
15437 {
15443 {
15446 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15451 }
15454 {
15456 decl);
15458 }
15461 {
15463 decl);
15465 }
15466 else
15468 }
15471 }
15473 {
15478 {
15481 }
15482 }
15483 }
15486 {
15490 }
15491 else
15495 {
15506 {
15514 }
15515 else
15521 {
15527 }
15531 {
15539 }
15540 else
15546 }
15552 #undef RECUR
15553 }
15555 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15556 of OMP_TARGET's body. */
15558 static tree
15560 {
15563 {
15572 }
15574 }
15576 /* Helper function for tsubst_expr. For decomposition declaration
15577 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15578 also the corresponding decls representing the identifiers
15579 of the decomposition declaration. Return DECL if successful
15580 or error_mark_node otherwise, set *FIRST to the first decl
15581 in the list chained through DECL_CHAIN and *CNT to the number
15582 of such decls. */
15584 static tree
15588 {
15593 decl2
15598 {
15614 {
15617 }
15618 else
15620 }
15623 }
15625 /* Like tsubst_copy for expressions, etc. but also does semantic
15626 processing. */
15628 tree
15631 {
15632 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15633 #define RECUR(NODE) \
15634 tsubst_expr ((NODE), args, complain, in_decl, \
15635 integral_constant_expression_p)
15638 tree r;
15639 location_t loc;
15651 {
15653 {
15654 tree_stmt_iterator i;
15658 }
15673 else
15682 {
15684 tree init;
15690 {
15700 else
15702 }
15704 {
15705 /* Don't build up decls for a variadic capture proxy, we'll
15706 instantiate the elements directly as needed. */
15708 }
15709 else
15710 {
15714 {
15715 /* By marking the declaration as instantiated, we avoid
15716 trying to instantiate it. Since instantiate_decl can't
15717 handle local variables, and since we've already done
15718 all that needs to be done, that's the right thing to
15719 do. */
15724 /* Anonymous aggregates are a special case. */
15727 {
15730 {
15734 }
15736 }
15742 {
15747 }
15748 else
15749 {
15754 {
15755 /* For __PRETTY_FUNCTION__ we have to adjust the
15756 initializer. */
15760 }
15761 else
15765 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15771 {
15773 tree first;
15779 }
15780 }
15781 }
15782 }
15785 }
15800 {
15808 {
15810 tree first;
15815 }
15816 else
15821 }
15847 else
15848 {
15855 }
15861 {
15870 }
15878 else
15886 else
15907 {
15914 }
15918 {
15920 tree label;
15927 }
15933 /* Computed goto's must be tsubst'd into. On the other hand,
15934 non-computed gotos must not be; the identifier in question
15935 will have no binding. */
15937 else
15943 {
15959 }
15964 {
15969 }
15970 else
15971 {
15976 else
15983 else
15989 else
15991 }
15995 {
15999 {
16001 /* Prevent instantiate_decl from trying to instantiate
16002 this variable. We've already done all that needs to be
16003 done. */
16006 }
16011 }
16017 {
16018 /* Local classes are not independent templates; they are
16019 instantiated along with their containing function. And this
16020 way we don't have to deal with pushing out of one local class
16021 to instantiate a member of another local class. */
16022 tree fn;
16023 /* Closures are handled by the LAMBDA_EXPR. */
16030 }
16034 {
16035 tree condition;
16038 condition =
16040 args,
16049 }
16055 in_decl);
16092 {
16107 in_decl);
16109 {
16116 }
16128 integral_constant_expression_p);
16139 else
16140 {
16148 }
16152 }
16157 /* FALLTHRU */
16164 in_decl);
16181 in_decl);
16192 {
16195 {
16196 /* For combined target teams, ensure the num_teams and
16197 thread_limit clause expressions are evaluated on the host,
16198 before entering the target construct. */
16199 tree c;
16205 {
16214 OMP_CLAUSE_FIRSTPRIVATE);
16218 }
16219 }
16220 }
16280 {
16285 {
16288 }
16294 }
16295 else
16296 {
16303 {
16306 }
16309 {
16314 {
16317 }
16323 }
16324 else
16325 {
16329 }
16332 }
16336 {
16342 {
16346 {
16351 }
16355 }
16356 else
16357 {
16362 }
16363 }
16367 {
16371 }
16391 /* If the first operand was a statement, we're done with it. */
16395 complain));
16407 integral_constant_expression_p));
16408 }
16411 out:
16414 #undef RECUR
16415 #undef RETURN
16416 }
16418 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16419 function. For description of the body see comment above
16420 cp_parser_omp_declare_reduction_exprs. */
16422 static void
16424 {
16430 tree_stmt_iterator tsi;
16441 {
16460 }
16462 {
16482 }
16483 }
16485 /* T is a postfix-expression that is not being used in a function
16486 call. Return the substituted version of T. */
16488 static tree
16490 tsubst_flags_t complain,
16491 tree in_decl)
16492 {
16496 else
16502 }
16504 /* Like tsubst but deals with expressions and performs semantic
16505 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16507 tree
16509 tree args,
16510 tsubst_flags_t complain,
16511 tree in_decl,
16514 {
16515 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16516 #define RECUR(NODE) \
16517 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16519 integral_constant_expression_p)
16522 location_t loc;
16531 /* N3276 decltype magic only applies to calls at the top level or on the
16532 right side of a comma. */
16537 {
16540 /* Fall through. */
16542 {
16543 tree decl;
16544 cp_id_kind idk;
16549 {
16552 }
16554 /* Look up the name. */
16557 /* By convention, expressions use ERROR_MARK_NODE to indicate
16558 failure, not NULL_TREE. */
16564 integral_constant_expression_p,
16572 input_location);
16576 {
16580 }
16582 }
16585 {
16586 tree object;
16599 {
16602 }
16603 else
16610 else
16612 }
16615 {
16619 {
16620 /* A type conversion to reference type will be enclosed in
16621 such an indirect ref, but the substitution of the cast
16622 will have also added such an indirect ref. */
16625 }
16626 else
16634 }
16637 {
16641 }
16644 {
16651 flags));
16652 }
16655 {
16659 }
16666 {
16667 tree type;
16673 {
16678 }
16684 {
16702 }
16705 }
16739 else
16741 in_decl);
16776 {
16783 tree r = build_x_binary_op
16785 op0,
16787 ? ERROR_MARK
16789 op1,
16791 ? ERROR_MARK
16799 }
16802 {
16806 }
16819 {
16828 }
16833 /* Fall through */
16836 {
16837 tree r;
16843 {
16844 /* When there are no ARGS, we are trying to evaluate a
16845 non-dependent expression from the parser. Trying to do
16846 the substitutions may not work. */
16849 }
16850 else
16851 {
16856 else
16859 /*integral_constant_expression_p=*/
16863 }
16867 else
16871 {
16873 {
16875 {
16879 }
16880 else
16884 }
16886 }
16888 }
16891 {
16901 }
16917 {
16921 tree r = build_x_modify_expr
16924 /* TREE_NO_WARNING must be set if either the expression was
16925 parenthesized or it uses an operator such as >>= rather
16926 than plain assignment. In the former case, it was already
16927 set and must be copied. In the latter case,
16928 build_x_modify_expr sets it and it must not be reset
16929 here. */
16934 }
16939 /* Remember that there was a reference to this entity. */
16946 {
16951 tree ret;
16955 else
16956 {
16960 }
16962 /* If there was an initializer in the original tree, but it
16963 instantiated to an empty list, then we should pass a
16964 non-NULL empty vector to tell build_new that it was an
16965 empty initializer() rather than no initializer. This can
16966 only happen when the initializer is a pack expansion whose
16967 parameter packs are of length zero. */
16970 else
16971 {
16975 else
16976 {
16979 }
16980 }
16986 complain);
16994 }
16997 {
17003 complain));
17004 }
17007 {
17011 integral_constant_expression_p);
17013 op0,
17016 }
17019 {
17020 tree function;
17025 tree ret;
17028 /* Internal function with no arguments. */
17032 /* When we parsed the expression, we determined whether or
17033 not Koenig lookup should be performed. */
17036 {
17039 }
17041 {
17046 }
17048 {
17049 /* Do nothing; calling tsubst_copy_and_build on an identifier
17050 would incorrectly perform unqualified lookup again.
17052 Note that we can also have an IDENTIFIER_NODE if the earlier
17053 unqualified lookup found a member function; in that case
17054 koenig_p will be false and we do want to do the lookup
17055 again to find the instantiated member function.
17057 FIXME but doing that causes c++/15272, so we need to stop
17058 using IDENTIFIER_NODE in that situation. */
17060 }
17061 else
17062 {
17064 {
17070 }
17071 else
17076 /* Avoid error about taking the address of a constructor. */
17080 in_decl,
17082 integral_constant_expression_p);
17086 }
17091 {
17096 else
17097 {
17098 /* Expand the pack expansion and push each entry onto
17099 CALL_ARGS. */
17102 {
17107 {
17112 }
17113 }
17114 else
17115 {
17116 /* A partial substitution. Add one entry. */
17118 }
17119 }
17120 }
17122 /* We do not perform argument-dependent lookup if normal
17123 lookup finds a non-function, in accordance with the
17124 expected resolution of DR 218. */
17127 /* If lookup found a member function, the Koenig lookup is
17128 not appropriate, even if an unqualified-name was used
17129 to denote the function. */
17132 /* Only do this when substitution turns a dependent call
17133 into a non-dependent call. */
17141 {
17143 {
17144 /* For backwards compatibility and good diagnostics, try
17145 the unqualified lookup again if we aren't in SFINAE
17146 context. */
17147 tree unq = (tsubst_copy_and_build
17149 integral_constant_expression_p));
17151 {
17154 }
17157 {
17158 /* In a lambda fn, we have to be careful to not
17159 introduce new this captures. Legacy code can't
17160 be using lambdas anyway, so it's ok to be
17161 stricter. */
17165 "and no declarations were found by "
17166 "argument-dependent lookup at the point "
17173 else
17177 {
17189 {
17191 input_location);
17193 "declarations in dependent base %qT are "
17199 else
17203 }
17204 else
17206 "%qD declared here, later in the "
17209 {
17212 }
17213 }
17216 }
17217 }
17219 {
17224 }
17225 }
17227 /* Remember that there was a reference to this entity. */
17231 {
17234 }
17236 /* Put back tf_decltype for the actual call. */
17241 {
17245 {
17247 "wrong number of arguments to "
17250 }
17251 else
17253 input_location),
17258 /* Unsupported internal function with arguments. */
17260 }
17263 complain);
17265 {
17280 complain);
17281 else
17282 ret = (build_new_method_call
17287 complain));
17288 }
17289 else
17292 koenig_p,
17293 complain);
17298 {
17304 {
17310 {
17312 /* The thunk location is not interesting. */
17314 }
17315 }
17316 }
17319 }
17322 {
17328 {
17330 {
17335 }
17336 else
17337 {
17342 }
17344 }
17345 else
17346 {
17349 }
17353 }
17356 {
17361 input_location));
17362 }
17365 {
17373 {
17374 /* We have pack expansions, so expand those and
17375 create a new list out of it. */
17378 tree chain;
17381 /* Expand the argument expressions. */
17389 /* Build the rest of the list. */
17394 /* Determine the number of arguments. */
17396 {
17399 }
17402 else
17403 {
17404 /* Since we only performed a partial substitution into
17405 the argument pack, we only RETURN (a single list
17406 node. */
17413 }
17415 /* Convert the argument vectors into a TREE_LIST */
17418 {
17419 /* Grab the Ith values. */
17420 i--;
17423 value
17427 /* Build the list (backwards). */
17429 }
17432 }
17448 }
17451 {
17452 tree object;
17453 tree object_type;
17454 tree member;
17455 tree r;
17459 /* Remember that there was a reference to this entity. */
17470 else
17476 {
17481 }
17485 {
17487 {
17492 {
17495 }
17497 {
17502 }
17503 }
17504 }
17507 {
17508 /* Lookup the template functions now that we know what the
17509 scope is. */
17517 {
17520 args);
17521 member = (adjust_result_of_qualified_name_lookup
17523 object_type));
17524 }
17525 else
17526 {
17528 input_location);
17530 }
17531 }
17535 {
17537 {
17541 else
17544 }
17546 }
17550 complain);
17554 }
17561 {
17569 tree r;
17574 /* digest_init will do the wrong thing if we let it. */
17578 /* We do not want to process the index of aggregate
17579 initializers as they are identifier nodes which will be
17580 looked up by digest_init. */
17586 {
17588 /* An identifier index is looked up in the type
17589 being initialized, not the current scope. */
17594 {
17595 /* Substitute into the pack expansion. */
17597 in_decl);
17601 ;
17603 /* Just move the argument into place. */
17605 else
17606 {
17607 /* Update the length of the final CONSTRUCTOR
17608 arguments vector, and note that we will need to
17609 copy.*/
17612 }
17613 }
17614 else
17616 }
17619 {
17624 {
17626 {
17631 }
17632 else
17634 }
17635 }
17645 }
17648 {
17651 {
17654 }
17655 else
17656 {
17659 }
17660 }
17666 {
17667 /* We don't build decls for an instantiation of a
17668 variadic capture proxy, we instantiate the elements
17669 when needed. */
17672 }
17673 /* Fall through */
17676 {
17678 /* ??? We're doing a subset of finish_id_expression here. */
17680 && !processing_template_decl
17681 && !cp_unevaluated_operand
17684 {
17686 /* Replace an evaluated use of the thread_local variable with
17687 a call to its wrapper. */
17689 }
17691 {
17695 }
17698 /* If the original type was a reference, we'll be wrapped in
17699 the appropriate INDIRECT_REF. */
17702 }
17705 {
17709 }
17712 {
17713 tree object_ptr
17720 }
17727 {
17738 }
17741 {
17747 integral_constant_expression_p);
17751 /* If the resulting list of expression statement is empty,
17752 fold it further into void_node. */
17757 }
17760 {
17778 /* For a function or variable scope, we want to use tsubst so that we
17779 don't complain about referring to an auto before deduction. */
17782 {
17783 /* Look up the parameter we want directly, as tsubst_copy
17784 doesn't do what we need. */
17790 /* FIXME Work around the parm not having DECL_CONTEXT set. */
17793 }
17795 /* For a field, use tsubst_copy so that we look up the existing field
17796 rather than build a new one. */
17798 else
17805 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17807 /* Now that we know visibility, instantiate the type so we have a
17808 declaration of the op() for later calls to lambda_function. */
17819 }
17822 /* We can get here for a constant initializer of non-dependent type.
17823 FIXME stop folding in cp_parser_initializer_clause. */
17824 {
17826 complain);
17828 }
17832 integral_constant_expression_p));
17838 {
17843 complain));
17844 }
17850 /* Handle Objective-C++ constructs, if appropriate. */
17851 {
17852 tree subst
17857 }
17859 }
17861 #undef RECUR
17862 #undef RETURN
17863 out:
17866 }
17868 /* Verify that the instantiated ARGS are valid. For type arguments,
17869 make sure that the type's linkage is ok. For non-type arguments,
17870 make sure they are constants if they are integral or enumerations.
17871 Emit an error under control of COMPLAIN, and return TRUE on error. */
17873 static bool
17875 {
17879 {
17889 }
17891 {
17892 /* [basic.link]: A name with no linkage (notably, the name
17893 of a class or enumeration declared in a local scope)
17894 shall not be used to declare an entity with linkage.
17895 This implies that names with no linkage cannot be used as
17896 template arguments
17898 DR 757 relaxes this restriction for C++0x. */
17903 {
17904 /* DR 488 makes use of a type with no linkage cause
17905 type deduction to fail. */
17907 {
17910 else
17913 }
17915 }
17916 /* In order to avoid all sorts of complications, we do not
17917 allow variably-modified types as template arguments. */
17919 {
17923 }
17924 }
17925 /* Class template and alias template arguments should be OK. */
17927 ;
17928 /* A non-type argument of integral or enumerated type must be a
17929 constant. */
17934 {
17938 }
17940 }
17942 static bool
17944 {
17949 {
17952 }
17956 }
17958 /* We're out of SFINAE context now, so generate diagnostics for the access
17959 errors we saw earlier when instantiating D from TMPL and ARGS. */
17961 static void
17963 {
17975 }
17977 /* Instantiate the indicated variable, function, or alias template TMPL with
17978 the template arguments in TARG_PTR. */
17980 static tree
17982 {
17984 tree fndecl;
17985 tree gen_tmpl;
17986 tree spec;
17994 /* If this function is a clone, handle it specially. */
17996 {
17997 tree spec;
17998 tree clone;
18000 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18001 DECL_CLONED_FUNCTION. */
18007 /* Look for the clone. */
18011 /* We should always have found the clone by now. */
18014 }
18019 /* Check to see if we already have this specialization. */
18023 /* targ_ptr only has the innermost template args, so add the outer ones
18024 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18025 the case of a non-dependent call within a template definition). */
18026 targ_ptr = (add_outermost_template_args
18028 targ_ptr));
18030 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18031 but it doesn't seem to be on the hot path. */
18040 {
18042 {
18046 }
18048 }
18051 complain))
18054 /* We are building a FUNCTION_DECL, during which the access of its
18055 parameters and return types have to be checked. However this
18056 FUNCTION_DECL which is the desired context for access checking
18057 is not built yet. We solve this chicken-and-egg problem by
18058 deferring all checks until we have the FUNCTION_DECL. */
18061 /* Instantiation of the function happens in the context of the function
18062 template, not the context of the overload resolution we're doing. */
18064 /* If there are dependent arguments, e.g. because we're doing partial
18065 ordering, make sure processing_template_decl stays set. */
18069 {
18073 }
18079 {
18080 /* We need to determine if we're using a partial or explicit
18081 specialization now, because the type of the variable could be
18082 different. */
18088 {
18093 }
18094 }
18096 /* Substitute template parameters to obtain the specialization. */
18104 {
18107 }
18109 /* The DECL_TI_TEMPLATE should always be the immediate parent
18110 template, not the most general template. */
18114 /* Now we know the specialization, compute access previously
18115 deferred. Do no access control for inheriting constructors,
18116 as we already checked access for the inherited constructor. */
18119 {
18124 }
18127 /* If we've just instantiated the main entry point for a function,
18128 instantiate all the alternate entry points as well. We do this
18129 by cloning the instantiation of the main entry point, not by
18130 instantiating the template clones. */
18135 {
18137 {
18138 /* Remember to reinstantiate when we're out of SFINAE so the user
18139 can see the errors. */
18141 }
18143 }
18145 }
18147 /* Wrapper for instantiate_template_1. */
18149 tree
18151 {
18152 tree ret;
18157 }
18159 /* Instantiate the alias template TMPL with ARGS. Also push a template
18160 instantiation level, which instantiate_template doesn't do because
18161 functions and variables have sufficient context established by the
18162 callers. */
18164 static tree
18166 {
18173 {
18176 }
18178 args =
18186 /* We can't free this if a pending_template entry or last_error_tinst_level
18187 is pointing at it. */
18193 }
18195 /* PARM is a template parameter pack for FN. Returns true iff
18196 PARM is used in a deducible way in the argument list of FN. */
18198 static bool
18200 {
18203 {
18205 tree packs;
18211 {
18212 /* The template parameter pack is used in a function parameter
18213 pack. If this is the end of the parameter list, the
18214 template parameter pack is deducible. */
18217 else
18218 /* Otherwise, not. Well, it could be deduced from
18219 a non-pack parameter, but doing so would end up with
18220 a deduction mismatch, so don't bother. */
18222 }
18223 }
18224 /* The template parameter pack isn't used in any function parameter
18225 packs, but it might be used deeper, e.g. tuple<Args...>. */
18227 }
18229 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18230 NARGS elements of the arguments that are being used when calling
18231 it. TARGS is a vector into which the deduced template arguments
18232 are placed.
18234 Returns either a FUNCTION_DECL for the matching specialization of FN or
18235 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18236 true, diagnostics will be printed to explain why it failed.
18238 If FN is a conversion operator, or we are trying to produce a specific
18239 specialization, RETURN_TYPE is the return type desired.
18241 The EXPLICIT_TARGS are explicit template arguments provided via a
18242 template-id.
18244 The parameter STRICT is one of:
18246 DEDUCE_CALL:
18247 We are deducing arguments for a function call, as in
18248 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18249 deducing arguments for a call to the result of a conversion
18250 function template, as in [over.call.object].
18252 DEDUCE_CONV:
18253 We are deducing arguments for a conversion function, as in
18254 [temp.deduct.conv].
18256 DEDUCE_EXACT:
18257 We are deducing arguments when doing an explicit instantiation
18258 as in [temp.explicit], when determining an explicit specialization
18259 as in [temp.expl.spec], or when taking the address of a function
18260 template, as in [temp.deduct.funcaddr]. */
18262 tree
18264 tree explicit_targs,
18265 tree targs,
18268 tree return_type,
18269 unification_kind_t strict,
18273 {
18274 tree parms;
18275 tree fntype;
18288 tree tinst;
18294 full_targs = (add_outermost_template_args
18296 targs));
18301 /* In C++0x, it's possible to have a function template whose type depends
18302 on itself recursively. This is most obvious with decltype, but can also
18303 occur with enumeration scope (c++/48969). So we need to catch infinite
18304 recursion and reject the substitution at deduction time; this function
18305 will return error_mark_node for any repeated substitution.
18307 This also catches excessive recursion such as when f<N> depends on
18308 f<N-1> across all integers, and returns error_mark_node for all the
18309 substitutions back up to the initial one.
18311 This is, of course, not reentrant. */
18321 {
18322 /* [temp.deduct]
18324 The specified template arguments must match the template
18325 parameters in kind (i.e., type, nontype, template), and there
18326 must not be more arguments than there are parameters;
18327 otherwise type deduction fails.
18329 Nontype arguments must match the types of the corresponding
18330 nontype template parameters, or must be convertible to the
18331 types of the corresponding nontype parameters as specified in
18332 _temp.arg.nontype_, otherwise type deduction fails.
18334 All references in the function type of the function template
18335 to the corresponding template parameters are replaced by the
18336 specified template argument values. If a substitution in a
18337 template parameter or in the function type of the function
18338 template results in an invalid type, type deduction fails. */
18349 explicit_targs);
18351 /* Adjust any explicit template arguments before entering the
18352 substitution context. */
18353 explicit_targs
18355 complain,
18361 /* Substitute the explicit args into the function type. This is
18362 necessary so that, for instance, explicitly declared function
18363 arguments can match null pointed constants. If we were given
18364 an incomplete set of explicit args, we must not do semantic
18365 processing during substitution as we could create partial
18366 instantiations. */
18368 {
18373 /* Dig out the actual parm. */
18376 {
18379 }
18381 {
18384 }
18387 /* No explicit argument for this template parameter. */
18391 {
18392 /* Mark the argument pack as "incomplete". We could
18393 still deduce more arguments during unification.
18394 We remove this mark in type_unification_real. */
18396 {
18400 }
18402 /* We have some incomplete argument packs. */
18404 }
18405 }
18409 {
18412 }
18415 /* Ignore any access checks; we'll see them again in
18416 instantiate_template and they might have the wrong
18417 access path at this point. */
18429 /* Place the explicitly specified arguments in TARGS. */
18433 }
18435 /* Never do unification on the 'this' parameter. */
18439 {
18440 /* We're deducing for a call to the result of a template conversion
18441 function. The parms we really want are in return_type. */
18445 }
18447 {
18456 }
18458 /* We allow incomplete unification without an error message here
18459 because the standard doesn't seem to explicitly prohibit it. Our
18460 callers must be ready to deal with unification failures in any
18461 event. */
18464 /* If we aren't explaining yet, push tinst context so we can see where
18465 any errors (e.g. from class instantiations triggered by instantiation
18466 of default template arguments) come from. If we are explaining, this
18467 context is redundant. */
18469 {
18472 }
18474 /* type_unification_real will pass back any access checks from default
18475 template argument substitution. */
18487 /* Now that we have bindings for all of the template arguments,
18488 ensure that the arguments deduced for the template template
18489 parameters have compatible template parameter lists. We cannot
18490 check this property before we have deduced all template
18491 arguments, because the template parameter types of a template
18492 template parameter might depend on prior template parameters
18493 deduced after the template template parameter. The following
18494 ill-formed example illustrates this issue:
18496 template<typename T, template<T> class C> void f(C<5>, T);
18498 template<int N> struct X {};
18500 void g() {
18501 f(X<5>(), 5l); // error: template argument deduction fails
18502 }
18504 The template parameter list of 'C' depends on the template type
18505 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18506 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18507 time that we deduce 'C'. */
18510 {
18513 }
18515 /* All is well so far. Now, check:
18517 [temp.deduct]
18519 When all template arguments have been deduced, all uses of
18520 template parameters in nondeduced contexts are replaced with
18521 the corresponding deduced argument values. If the
18522 substitution results in an invalid type, as described above,
18523 type deduction fails. */
18526 {
18529 }
18531 /* Also collect access checks from the instantiation. */
18544 /* Now perform any access checks encountered during substitution. */
18551 /* If we're looking for an exact match, check that what we got
18552 is indeed an exact match. It might not be if some template
18553 parameters are used in non-deduced contexts. But don't check
18554 for an exact match if we have dependent template arguments;
18555 in that case we're doing partial ordering, and we already know
18556 that we have two candidates that will provide the actual type. */
18558 {
18562 tree sarg
18568 {
18572 }
18573 }
18575 /* After doing deduction with the inherited constructor, actually return an
18576 instantiation of the inheriting constructor. */
18582 fail:
18585 {
18587 /* Reset once we're all the way out. */
18589 }
18591 /* We can't free this if a pending_template entry or last_error_tinst_level
18592 is pointing at it. */
18598 }
18600 /* Adjust types before performing type deduction, as described in
18601 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
18602 sections are symmetric. PARM is the type of a function parameter
18603 or the return type of the conversion function. ARG is the type of
18604 the argument passed to the call, or the type of the value
18605 initialized with the result of the conversion function.
18606 ARG_EXPR is the original argument expression, which may be null. */
18608 static int
18612 tree arg_expr)
18613 {
18617 {
18622 /* Swap PARM and ARG throughout the remainder of this
18623 function; the handling is precisely symmetric since PARM
18624 will initialize ARG rather than vice versa. */
18629 /* Core issue #873: Do the DR606 thing (see below) for these cases,
18630 too, but here handle it by stripping the reference from PARM
18631 rather than by adding it to ARG. */
18639 /* Nothing else to do in this case. */
18644 }
18647 {
18648 /* [temp.deduct.call]
18650 If P is not a reference type:
18652 --If A is an array type, the pointer type produced by the
18653 array-to-pointer standard conversion (_conv.array_) is
18654 used in place of A for type deduction; otherwise,
18656 --If A is a function type, the pointer type produced by
18657 the function-to-pointer standard conversion
18658 (_conv.func_) is used in place of A for type deduction;
18659 otherwise,
18661 --If A is a cv-qualified type, the top level
18662 cv-qualifiers of A's type are ignored for type
18663 deduction. */
18668 else
18670 }
18672 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
18673 reference to a cv-unqualified template parameter that does not represent a
18674 template parameter of a class template (during class template argument
18675 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
18676 an lvalue, the type "lvalue reference to A" is used in place of A for type
18677 deduction. */
18684 /* try_one_overload doesn't provide an arg_expr, but
18685 functions are always lvalues. */
18689 /* [temp.deduct.call]
18691 If P is a cv-qualified type, the top level cv-qualifiers
18692 of P's type are ignored for type deduction. If P is a
18693 reference type, the type referred to by P is used for
18694 type deduction. */
18697 {
18700 }
18702 /* DR 322. For conversion deduction, remove a reference type on parm
18703 too (which has been swapped into ARG). */
18708 }
18710 /* Subroutine of unify_one_argument. PARM is a function parameter of a
18711 template which does contain any deducible template parameters; check if
18712 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
18713 unify_one_argument. */
18715 static int
18718 {
18719 tree type;
18723 else
18730 {
18734 }
18736 {
18741 }
18745 else
18747 }
18751 /* Returns true iff the expression EXPR is one from which a template
18752 argument can be deduced. In other words, if it's an undecorated
18753 use of a template non-type parameter. */
18755 static bool
18757 {
18758 /* Strip implicit conversions. */
18762 }
18764 /* Returns true iff the array domain DOMAIN uses a template parameter in a
18765 deducible way; that is, if it has a max value of <PARM> - 1. */
18767 static bool
18769 {
18778 }
18780 /* Returns true iff the template arguments ARGS use a template parameter
18781 in a deducible way. */
18783 static bool
18785 {
18787 {
18792 else
18793 {
18800 else
18802 }
18805 }
18807 }
18809 /* Returns true iff TYPE contains any deducible references to template
18810 parameters, as per 14.8.2.5. */
18812 static bool
18814 {
18818 /* T
18819 cv-list T
18820 TT<T>
18821 TT<i>
18822 TT<> */
18827 /* T*
18828 T&
18829 T&& */
18833 /* T[integer-constant ]
18834 type [i] */
18839 /* T type ::*
18840 type T::*
18841 T T::*
18842 T (type ::*)()
18843 type (T::*)()
18844 type (type ::*)(T)
18845 type (T::*)(T)
18846 T (type ::*)(T)
18847 T (T::*)()
18848 T (T::*)(T) */
18851 || (uses_deducible_template_parms
18854 /* template-name <T> (where template-name refers to a class template)
18855 template-name <i> (where template-name refers to a class template) */
18862 /* type (T)
18863 T()
18864 T(T) */
18867 {
18876 }
18879 }
18881 /* Subroutine of type_unification_real and unify_pack_expansion to
18882 handle unification of a single P/A pair. Parameters are as
18883 for those functions. */
18885 static int
18889 {
18896 /* We can't deduce anything from this, but we might get all the
18897 template args from other function args. */
18900 /* Implicit conversions (Clause 4) will be performed on a function
18901 argument to convert it to the type of the corresponding function
18902 parameter if the parameter type contains no template-parameters that
18903 participate in template argument deduction. */
18906 /* For function parameters with no deducible template parameters,
18907 just return. We'll check non-dependent conversions later. */
18911 {
18913 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
18914 | UNIFY_ALLOW_MORE_CV_QUAL
18928 }
18930 /* We only do these transformations if this is the top-level
18931 parameter_type_list in a call or declaration matching; in other
18932 situations (nested function declarators, template argument lists) we
18933 won't be comparing a type to an expression, and we don't do any type
18934 adjustments. */
18936 {
18938 {
18941 {
18942 /* [temp.deduct.type] A template-argument can be
18943 deduced from a pointer to function or pointer
18944 to member function argument if the set of
18945 overloaded functions does not contain function
18946 templates and at most one of a set of
18947 overloaded functions provides a unique
18948 match. */
18955 }
18961 }
18963 arg_strict |=
18965 }
18966 else
18971 /* For deduction from an init-list we need the actual list. */
18975 }
18977 /* for_each_template_parm callback that always returns 0. */
18979 static int
18981 {
18983 }
18985 /* for_each_template_parm any_fn callback to handle deduction of a template
18986 type argument from the type of an array bound. */
18988 static int
18990 {
18998 {
19004 }
19006 /* Keep walking. */
19008 }
19010 /* Try to deduce any not-yet-deduced template type arguments from the type of
19011 an array bound. This is handled separately from unify because 14.8.2.5 says
19012 "The type of a type parameter is only deduced from an array bound if it is
19013 not otherwise deduced." */
19015 static void
19017 {
19022 }
19024 /* Most parms like fn_type_unification.
19026 If SUBR is 1, we're being called recursively (to unify the
19027 arguments of a function or method parameter of a function
19028 template).
19030 CHECKS is a pointer to a vector of access checks encountered while
19031 substituting default template arguments. */
19033 static int
19035 tree full_targs,
19036 tree xparms,
19040 unification_kind_t strict,
19044 {
19049 tree parms;
19060 /* Reset the number of non-defaulted template arguments contained
19061 in TARGS. */
19064 again:
19072 {
19077 /* For a function parameter pack that occurs at the end of the
19078 parameter-declaration-list, the type A of each remaining
19079 argument of the call is compared with the type P of the
19080 declarator-id of the function parameter pack. */
19086 /* For a function parameter pack that does not occur at the
19087 end of the parameter-declaration-list, the type of the
19088 parameter pack is a non-deduced context. */
19095 explain_p))
19097 }
19102 {
19103 /* Unify the remaining arguments with the pack expansion type. */
19104 tree argvec;
19107 /* Allocate a TREE_VEC and copy in all of the arguments */
19112 /* Copy the parameter into parmvec. */
19118 /* Advance to the end of the list of parameters. */
19120 }
19122 /* Fail if we've reached the end of the parm list, and more args
19123 are present, and the parm list isn't variadic. */
19126 /* Fail if parms are left and they don't have default values and
19127 they aren't all deduced as empty packs (c++/57397). This is
19128 consistent with sufficient_parms_p. */
19131 {
19135 do
19136 {
19139 count++;
19141 }
19145 type_pack_p);
19146 }
19149 {
19150 tsubst_flags_t complain = (explain_p
19151 ? tf_warning_or_error
19156 {
19160 /* Clear the "incomplete" flags on all argument packs now so that
19161 substituting them into later default arguments works. */
19163 {
19166 }
19174 {
19179 }
19181 /* If this is an undeduced nontype parameter that depends on
19182 a type parameter, try another pass; its type may have been
19183 deduced from a later argument than the one from which
19184 this parameter can be deduced. */
19188 {
19191 }
19193 /* Core issue #226 (C++0x) [temp.deduct]:
19195 If a template argument has not been deduced, its
19196 default template argument, if any, is used.
19198 When we are in C++98 mode, TREE_PURPOSE will either
19199 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19200 to explicitly check cxx_dialect here. */
19202 /* OK, there is a default argument. Wait until after the
19203 conversion check to do substitution. */
19206 /* If the type parameter is a parameter pack, then it will
19207 be deduced to an empty parameter pack. */
19209 {
19210 tree arg;
19213 {
19217 }
19218 else
19225 }
19228 }
19230 /* DR 1391: All parameters have args, now check non-dependent parms for
19231 convertibility. */
19235 {
19241 /* For a function parameter pack that occurs at the end of the
19242 parameter-declaration-list, the type A of each remaining
19243 argument of the call is compared with the type P of the
19244 declarator-id of the function parameter pack. */
19250 /* For a function parameter pack that does not occur at the
19251 end of the parameter-declaration-list, the type of the
19252 parameter pack is a non-deduced context. */
19261 explain_p))
19263 }
19265 /* Now substitute into the default template arguments. */
19267 {
19291 else
19299 {
19301 /* The position of the first default template argument,
19302 is also the number of non-defaulted arguments in TARGS.
19303 Record that. */
19306 }
19307 }
19311 }
19317 }
19319 /* Subroutine of type_unification_real. Args are like the variables
19320 at the call site. ARG is an overloaded function (or template-id);
19321 we try deducing template args from each of the overloads, and if
19322 only one succeeds, we go with that. Modifies TARGS and returns
19323 true on success. */
19325 static bool
19327 tree targs,
19328 tree parm,
19329 tree arg,
19330 unification_kind_t strict,
19333 {
19340 {
19343 }
19344 else
19348 /* Handle `&x' where `x' is some static or non-static member
19349 function name. */
19355 /* Strip baselink information. */
19360 {
19361 /* If we got some explicit template args, we need to plug them into
19362 the affected templates before we try to unify, in case the
19363 explicit args will completely resolve the templates in question. */
19370 {
19383 {
19388 {
19391 }
19392 }
19395 }
19396 /* If no templates (or more than one) are fully resolved by the
19397 explicit arguments, this template-id is a non-deduced context; it
19398 could still be OK if we deduce all template arguments for the
19399 enclosing call through other arguments. */
19402 }
19405 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19406 -- but the deduction does not succeed because the expression is
19407 not just the function on its own. */
19409 else
19415 {
19418 }
19420 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19421 to function or pointer to member function argument if the set of
19422 overloaded functions does not contain function templates and at most
19423 one of a set of overloaded functions provides a unique match.
19425 So if we found multiple possibilities, we return success but don't
19426 deduce anything. */
19429 {
19433 {
19438 /* Don't forget explicit template arguments in a pack. */
19442 }
19443 }
19448 }
19450 /* Core DR 115: In contexts where deduction is done and fails, or in
19451 contexts where deduction is not done, if a template argument list is
19452 specified and it, along with any default template arguments, identifies
19453 a single function template specialization, then the template-id is an
19454 lvalue for the function template specialization. */
19456 tree
19458 {
19471 {
19474 }
19476 {
19479 }
19481 {
19484 }
19487 {
19491 /* If we got some explicit template args, we need to plug them into
19492 the affected templates before we try to unify, in case the
19493 explicit args will completely resolve the templates in question. */
19501 {
19514 {
19517 {
19520 }
19522 {
19525 }
19526 }
19527 }
19529 {
19537 {
19538 tree base
19541 }
19545 }
19547 /* There were no good options and at least one bad one, so let the
19548 user know what the problem is. */
19550 }
19552 }
19554 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19555 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19556 different overloads deduce different arguments for a given parm.
19557 ADDR_P is true if the expression for which deduction is being
19558 performed was of the form "& fn" rather than simply "fn".
19560 Returns 1 on success. */
19562 static int
19564 tree orig_targs,
19565 tree targs,
19566 tree parm,
19567 tree arg,
19568 unification_kind_t strict,
19572 {
19574 tree tempargs;
19580 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19581 to function or pointer to member function argument if the set of
19582 overloaded functions does not contain function templates and at most
19583 one of a set of overloaded functions provides a unique match.
19585 So if this is a template, just return success. */
19597 /* We don't copy orig_targs for this because if we have already deduced
19598 some template args from previous args, unify would complain when we
19599 try to deduce a template parameter for the same argument, even though
19600 there isn't really a conflict. */
19607 /* First make sure we didn't deduce anything that conflicts with
19608 explicitly specified args. */
19610 {
19617 /* Since we're unifying against ourselves, we will fill in
19618 template args used in the function parm list with our own
19619 template parms. Discard them. */
19622 {
19623 /* Check that the argument at each index of the deduced argument pack
19624 is equivalent to the corresponding explicitly specified argument.
19625 We may have deduced more arguments than were explicitly specified,
19626 and that's OK. */
19642 }
19645 }
19648 {
19653 }
19656 }
19658 /* PARM is a template class (perhaps with unbound template
19659 parameters). ARG is a fully instantiated type. If ARG can be
19660 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
19661 TARGS are as for unify. */
19663 static tree
19666 {
19667 tree copy_of_targs;
19677 /* We need to make a new template argument vector for the call to
19678 unify. If we used TARGS, we'd clutter it up with the result of
19679 the attempted unification, even if this class didn't work out.
19680 We also don't want to commit ourselves to all the unifications
19681 we've already done, since unification is supposed to be done on
19682 an argument-by-argument basis. In other words, consider the
19683 following pathological case:
19685 template <int I, int J, int K>
19686 struct S {};
19688 template <int I, int J>
19689 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
19691 template <int I, int J, int K>
19692 void f(S<I, J, K>, S<I, I, I>);
19694 void g() {
19695 S<0, 0, 0> s0;
19696 S<0, 1, 2> s2;
19698 f(s0, s2);
19699 }
19701 Now, by the time we consider the unification involving `s2', we
19702 already know that we must have `f<0, 0, 0>'. But, even though
19703 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
19704 because there are two ways to unify base classes of S<0, 1, 2>
19705 with S<I, I, I>. If we kept the already deduced knowledge, we
19706 would reject the possibility I=1. */
19710 {
19714 }
19716 /* If unification failed, we're done. */
19722 }
19724 /* Given a template type PARM and a class type ARG, find the unique
19725 base type in ARG that is an instance of PARM. We do not examine
19726 ARG itself; only its base-classes. If there is not exactly one
19727 appropriate base class, return NULL_TREE. PARM may be the type of
19728 a partial specialization, as well as a plain template type. Used
19729 by unify. */
19731 static enum template_base_result
19734 {
19736 tree binfo;
19742 {
19743 /* The type could not be completed. */
19746 }
19748 /* Walk in inheritance graph order. The search order is not
19749 important, and this avoids multiple walks of virtual bases. */
19751 {
19756 {
19757 /* If there is more than one satisfactory baseclass, then:
19759 [temp.deduct.call]
19761 If they yield more than one possible deduced A, the type
19762 deduction fails.
19764 applies. */
19766 {
19769 }
19772 }
19773 }
19777 }
19779 /* Returns the level of DECL, which declares a template parameter. */
19781 static int
19783 {
19785 {
19795 }
19797 }
19799 /* Decide whether ARG can be unified with PARM, considering only the
19800 cv-qualifiers of each type, given STRICT as documented for unify.
19801 Returns nonzero iff the unification is OK on that basis. */
19803 static int
19805 {
19811 {
19812 /* Although a CVR qualifier is ignored when being applied to a
19813 substituted template parameter ([8.3.2]/1 for example), that
19814 does not allow us to unify "const T" with "int&" because both
19815 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
19816 It is ok when we're allowing additional CV qualifiers
19817 at the outer level [14.8.2.1]/3,1st bullet. */
19827 }
19838 }
19840 /* Determines the LEVEL and INDEX for the template parameter PARM. */
19841 void
19843 {
19847 {
19850 }
19851 else
19852 {
19855 }
19856 }
19858 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
19859 do { \
19860 if (unify (TP, TA, P, A, S, EP)) \
19861 return 1; \
19862 } while (0)
19864 /* Unifies the remaining arguments in PACKED_ARGS with the pack
19865 expansion at the end of PACKED_PARMS. Returns 0 if the type
19866 deduction succeeds, 1 otherwise. STRICT is the same as in
19867 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
19868 function call argument list. We'll need to adjust the arguments to make them
19869 types. SUBR tells us if this is from a recursive call to
19870 type_unification_real, or for comparing two template argument
19871 lists. */
19873 static int
19877 {
19878 tree parm
19888 /* Determine the parameter packs we will be deducing from the
19889 pattern, and record their current deductions. */
19892 {
19896 /* Determine the index and level of this parameter pack. */
19899 /* Keep track of the parameter packs and their corresponding
19900 argument packs. */
19903 }
19905 /* Loop through all of the arguments that have not yet been
19906 unified and unify each with the pattern. */
19908 {
19909 tree parm;
19913 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
19914 or the element of its argument pack at the current index if
19915 this argument was explicitly specified. */
19917 {
19926 {
19929 }
19931 }
19933 /* If we had explicit template arguments, substitute them into the
19934 pattern before deduction. */
19936 {
19937 /* Some arguments might still be unspecified or dependent. */
19945 NULL_TREE);
19950 }
19951 else
19954 /* Unify the pattern with the current argument. */
19956 explain_p))
19959 /* For each parameter pack, collect the deduced value. */
19961 {
19967 }
19968 }
19970 /* Verify that the results of unification with the parameter packs
19971 produce results consistent with what we've seen before, and make
19972 the deduced argument packs available. */
19974 {
19981 /* By default keep the original deduced argument pack.
19982 If necessary, more specific code is going to update the
19983 resulting deduced argument later down in this function. */
19987 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
19988 actually deduce anything. */
19996 {
19997 /* If we had fewer function args than explicit template args,
19998 just use the explicits. */
20003 }
20006 {
20007 tree result;
20008 /* Build the deduced *_ARGUMENT_PACK. */
20010 {
20015 }
20016 else
20021 /* Note the deduced argument packs for this parameter
20022 pack. */
20024 }
20028 {
20029 /* We only had the explicitly-provided arguments before, but
20030 now we have a complete set of arguments. */
20036 }
20037 else
20038 {
20044 /* Inconsistent unification of this parameter pack. */
20046 bad_old_arg,
20047 bad_new_arg);
20048 }
20049 }
20052 }
20054 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20055 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20056 parameters and return value are as for unify. */
20058 static int
20062 {
20063 tree parm_max;
20064 tree arg_max;
20068 /* Our representation of array types uses "N - 1" as the
20069 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20070 not an integer constant. We cannot unify arbitrarily
20071 complex expressions, so we eliminate the MINUS_EXPRs
20072 here. */
20076 {
20079 }
20083 {
20084 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20085 trying to unify the type of a variable with the type
20086 of a template parameter. For example:
20088 template <unsigned int N>
20089 void f (char (&) [N]);
20090 int g();
20091 void h(int i) {
20092 char a[g(i)];
20093 f(a);
20094 }
20096 Here, the type of the ARG will be "int [g(i)]", and
20097 may be a SAVE_EXPR, etc. */
20101 }
20103 /* If only one of the bounds used a MINUS_EXPR, compensate
20104 by adding one to the other bound. */
20107 integer_type_node,
20108 parm_max,
20109 integer_one_node);
20112 integer_type_node,
20113 arg_max,
20114 integer_one_node);
20118 }
20120 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20124 static pa_kind_t
20126 {
20135 else
20137 }
20139 /* Deduce the value of template parameters. TPARMS is the (innermost)
20140 set of template parameters to a template. TARGS is the bindings
20141 for those template parameters, as determined thus far; TARGS may
20142 include template arguments for outer levels of template parameters
20143 as well. PARM is a parameter to a template function, or a
20144 subcomponent of that parameter; ARG is the corresponding argument.
20145 This function attempts to match PARM with ARG in a manner
20146 consistent with the existing assignments in TARGS. If more values
20147 are deduced, then TARGS is updated.
20149 Returns 0 if the type deduction succeeds, 1 otherwise. The
20150 parameter STRICT is a bitwise or of the following flags:
20152 UNIFY_ALLOW_NONE:
20153 Require an exact match between PARM and ARG.
20154 UNIFY_ALLOW_MORE_CV_QUAL:
20155 Allow the deduced ARG to be more cv-qualified (by qualification
20156 conversion) than ARG.
20157 UNIFY_ALLOW_LESS_CV_QUAL:
20158 Allow the deduced ARG to be less cv-qualified than ARG.
20159 UNIFY_ALLOW_DERIVED:
20160 Allow the deduced ARG to be a template base class of ARG,
20161 or a pointer to a template base class of the type pointed to by
20162 ARG.
20163 UNIFY_ALLOW_INTEGER:
20164 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20165 case for more information.
20166 UNIFY_ALLOW_OUTER_LEVEL:
20167 This is the outermost level of a deduction. Used to determine validity
20168 of qualification conversions. A valid qualification conversion must
20169 have const qualified pointers leading up to the inner type which
20170 requires additional CV quals, except at the outer level, where const
20171 is not required [conv.qual]. It would be normal to set this flag in
20172 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20173 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20174 This is the outermost level of a deduction, and PARM can be more CV
20175 qualified at this point.
20176 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20177 This is the outermost level of a deduction, and PARM can be less CV
20178 qualified at this point. */
20180 static int
20183 {
20185 tree targ;
20186 tree tparm;
20188 tsubst_flags_t complain = (explain_p
20189 ? tf_warning_or_error
20192 /* I don't think this will do the right thing with respect to types.
20193 But the only case I've seen it in so far has been array bounds, where
20194 signedness is the only information lost, and I think that will be
20195 okay. */
20203 /* We can't deduce anything from this, but we might get all the
20204 template args from other function args. */
20210 /* If PARM uses template parameters, then we can't bail out here,
20211 even if ARG == PARM, since we won't record unifications for the
20212 template parameters. We might need them if we're trying to
20213 figure out which of two things is more specialized. */
20217 /* Handle init lists early, so the rest of the function can assume
20218 we're dealing with a type. */
20220 {
20225 /* Replace T with std::initializer_list<T> for deduction. */
20232 /* We can only deduce from an initializer list argument if the
20233 parameter is std::initializer_list or an array; otherwise this
20234 is a non-deduced context. */
20239 else
20240 {
20242 /* Deduction is defined in terms of a single type, so just punt
20243 on the (bizarre) std::initializer_list<T...>. */
20246 }
20249 {
20256 {
20260 /* It should only be possible to get here for a call. */
20262 elt_strict |= maybe_adjust_types_for_deduction
20265 }
20268 explain_p);
20269 }
20273 {
20274 /* Also deduce from the length of the initializer list. */
20281 }
20283 /* If the std::initializer_list<T> deduction worked, replace the
20284 deduced A with std::initializer_list<A>. */
20286 {
20291 }
20293 }
20295 /* If parm and arg aren't the same kind of thing (template, type, or
20296 expression), fail early. */
20300 /* Immediately reject some pairs that won't unify because of
20301 cv-qualification mismatches. */
20304 /* It is the elements of the array which hold the cv quals of an array
20305 type, and the elements might be template type parms. We'll check
20306 when we recurse. */
20308 /* We check the cv-qualifiers when unifying with template type
20309 parameters below. We want to allow ARG `const T' to unify with
20310 PARM `T' for example, when computing which of two templates
20311 is more specialized, for example. */
20325 {
20329 /* In a type which contains a nested-name-specifier, template
20330 argument values cannot be deduced for template parameters used
20331 within the nested-name-specifier. */
20343 /* The PARM is not one we're trying to unify. Just check
20344 to see if it matches ARG. */
20345 {
20350 else
20352 }
20359 /* Check for mixed types and values. */
20367 {
20370 {
20371 /* First try to match ARG directly. */
20373 explain_p);
20375 {
20376 /* Otherwise, look for a suitable base of ARG, as below. */
20383 }
20384 }
20385 /* ARG must be constructed from a template class or a template
20386 template parameter. */
20391 /* Deduce arguments T, i from TT<T> or TT<i>. */
20397 /* Fall through to deduce template name. */
20398 }
20402 {
20403 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20405 /* Simple cases: Value already set, does match or doesn't. */
20410 }
20411 else
20412 {
20413 /* If PARM is `const T' and ARG is only `int', we don't have
20414 a match unless we are allowing additional qualification.
20415 If ARG is `const int' and PARM is just `T' that's OK;
20416 that binds `const int' to `T'. */
20421 /* Consider the case where ARG is `const volatile int' and
20422 PARM is `const T'. Then, T should be `volatile int'. */
20423 arg = cp_build_qualified_type_real
20428 /* Simple cases: Value already set, does match or doesn't. */
20434 /* Make sure that ARG is not a variable-sized array. (Note
20435 that were talking about variable-sized arrays (like
20436 `int[n]'), rather than arrays of unknown size (like
20437 `int[]').) We'll get very confused by such a type since
20438 the bound of the array is not constant, and therefore
20439 not mangleable. Besides, such types are not allowed in
20440 ISO C++, so we can do as we please here. We do allow
20441 them for 'auto' deduction, since that isn't ABI-exposed. */
20445 /* Strip typedefs as in convert_template_argument. */
20447 }
20449 /* If ARG is a parameter pack or an expansion, we cannot unify
20450 against it unless PARM is also a parameter pack. */
20455 /* If the argument deduction results is a METHOD_TYPE,
20456 then there is a problem.
20457 METHOD_TYPE doesn't map to any real C++ type the result of
20458 the deduction can not be of that type. */
20472 {
20473 /* The PARM is not one we're trying to unify. Just check
20474 to see if it matches ARG. */
20480 }
20486 {
20491 }
20494 /* We deduce from array bounds in try_array_deduction. */
20498 {
20503 }
20505 /* [temp.deduct.type] If, in the declaration of a function template
20506 with a non-type template-parameter, the non-type
20507 template-parameter is used in an expression in the function
20508 parameter-list and, if the corresponding template-argument is
20509 deduced, the template-argument type shall match the type of the
20510 template-parameter exactly, except that a template-argument
20511 deduced from an array bound may be of any integral type.
20512 The non-type parameter might use already deduced type parameters. */
20515 {
20519 }
20522 /* Template-parameter dependent expression. Just accept it for now.
20523 It will later be processed in convert_template_argument. */
20524 ;
20529 /* Convert the ARG to the type of PARM; the deduced non-type
20530 template argument must exactly match the types of the
20531 corresponding parameter. */
20534 /* We haven't deduced the type of this parameter yet. Try again
20535 later. */
20537 else
20540 /* If ARG is a parameter pack or an expansion, we cannot unify
20541 against it unless PARM is also a parameter pack. */
20546 {
20549 }
20554 {
20555 /* A pointer-to-member constant can be unified only with
20556 another constant. */
20560 /* Just unify the class member. It would be useless (and possibly
20561 wrong, depending on the strict flags) to unify also
20562 PTRMEM_CST_CLASS, because we want to be sure that both parm and
20563 arg refer to the same variable, even if through different
20564 classes. For instance:
20566 struct A { int x; };
20567 struct B : A { };
20569 Unification of &A::x and &B::x must succeed. */
20572 }
20575 {
20579 /* [temp.deduct.call]
20581 A can be another pointer or pointer to member type that can
20582 be converted to the deduced A via a qualification
20583 conversion (_conv.qual_).
20585 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
20586 This will allow for additional cv-qualification of the
20587 pointed-to types if appropriate. */
20590 /* The derived-to-base conversion only persists through one
20591 level of pointers. */
20596 }
20628 /* We have already checked cv-qualification at the top of the
20629 function. */
20633 /* As far as unification is concerned, this wins. Later checks
20634 will invalidate it if necessary. */
20637 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
20638 /* Type INTEGER_CST can come from ordinary constant template args. */
20650 {
20660 /* Check for pack expansions in the parameters. */
20662 {
20664 {
20666 /* We can unify against something with a trailing
20667 parameter pack. */
20669 else
20670 /* [temp.deduct.type]/9: If the template argument list of
20671 P contains a pack expansion that is not the last
20672 template argument, the entire template argument list
20673 is a non-deduced context. */
20675 }
20676 }
20678 /* If we don't have enough arguments to satisfy the parameters
20679 (not counting the pack expression at the end), or we have
20680 too many arguments for a parameter list that doesn't end in
20681 a pack expression, we can't unify. */
20687 /* Unify all of the parameters that precede the (optional)
20688 pack expression. */
20690 {
20695 }
20698 DEDUCE_EXACT,
20701 }
20709 {
20717 }
20722 {
20726 {
20727 /* First, we try to unify the PARM and ARG directly. */
20732 {
20733 /* Fallback to the special case allowed in
20734 [temp.deduct.call]:
20736 If P is a class, and P has the form
20737 template-id, then A can be a derived class of
20738 the deduced A. Likewise, if P is a pointer to
20739 a class of the form template-id, A can be a
20740 pointer to a derived class pointed to by the
20741 deduced A. */
20747 {
20748 /* Don't give the derived diagnostic if we're
20749 already dealing with the same template. */
20750 bool same_template
20756 }
20757 }
20758 }
20762 /* Perhaps PARM is something like S<U> and ARG is S<int>.
20763 Then, we should unify `int' and `U'. */
20765 else
20766 /* There's no chance of unification succeeding. */
20771 }
20778 {
20781 tree a;
20787 /* CV qualifications for methods can never be deduced, they must
20788 match exactly. We need to check them explicitly here,
20789 because type_unification_real treats them as any other
20790 cv-qualified parameter. */
20792 && (!check_cv_quals_for_unify
20820 {
20832 }
20835 }
20838 /* Unify a pointer to member with a pointer to member function, which
20839 deduces the type of the member as a function type. */
20841 {
20842 /* Check top-level cv qualifiers */
20850 /* Determine the type of the function we are unifying against. */
20854 }
20873 /* Matched cases are handled by the ARG == PARM test above. */
20877 /* We might get a variable as a non-type template argument in parm if the
20878 corresponding parameter is type-dependent. Make any necessary
20879 adjustments based on whether arg is a reference. */
20883 {
20888 }
20889 /* Now use the normal expression code to check whether they match. */
20900 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
20901 or UNDERLYING_TYPE nodes. */
20905 /* Unification fails if we hit an error node. */
20910 {
20915 }
20916 /* FALLTHRU */
20919 /* An unresolved overload is a nondeduced context. */
20923 expr:
20924 /* We must be looking at an expression. This can happen with
20925 something like:
20927 template <int I>
20928 void foo(S<I>, S<I + 2>);
20930 This is a "nondeduced context":
20932 [deduct.type]
20934 The nondeduced contexts are:
20936 --A type that is a template-id in which one or more of
20937 the template-arguments is an expression that references
20938 a template-parameter.
20940 In these cases, we assume deduction succeeded, but don't
20941 actually infer any unifications. */
20946 else
20948 }
20949 }
20950 #undef RECUR_AND_CHECK_FAILURE
20951 \f
20952 /* Note that DECL can be defined in this translation unit, if
20953 required. */
20955 static void
20957 {
20958 tree clone;
20962 }
20964 /* Called if RESULT is explicitly instantiated, or is a member of an
20965 explicitly instantiated class. */
20967 void
20969 {
20972 /* If this entity has already been written out, it's too late to
20973 make any modifications. */
20977 /* For anonymous namespace we don't need to do anything. */
20979 {
20982 }
20985 /* The TREE_PUBLIC flag for function declarations will have been
20986 set correctly by tsubst. */
20989 /* This might have been set by an earlier implicit instantiation. */
20994 else
20995 {
20998 /* Always make artificials weak. */
21001 /* For WIN32 we also want to put explicit instantiations in
21002 linkonce sections. */
21005 }
21007 /* If EXTERN_P, then this function will not be emitted -- unless
21008 followed by an explicit instantiation, at which point its linkage
21009 will be adjusted. If !EXTERN_P, then this function will be
21010 emitted here. In neither circumstance do we want
21011 import_export_decl to adjust the linkage. */
21013 }
21015 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21016 important template arguments. If any are missing, we check whether
21017 they're important by using error_mark_node for substituting into any
21018 args that were used for partial ordering (the ones between ARGS and END)
21019 and seeing if it bubbles up. */
21021 static bool
21023 {
21028 {
21031 }
21033 {
21037 }
21039 }
21041 /* Given two function templates PAT1 and PAT2, return:
21043 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21044 -1 if PAT2 is more specialized than PAT1.
21045 0 if neither is more specialized.
21047 LEN indicates the number of parameters we should consider
21048 (defaulted parameters should not be considered).
21050 The 1998 std underspecified function template partial ordering, and
21051 DR214 addresses the issue. We take pairs of arguments, one from
21052 each of the templates, and deduce them against each other. One of
21053 the templates will be more specialized if all the *other*
21054 template's arguments deduce against its arguments and at least one
21055 of its arguments *does* *not* deduce against the other template's
21056 corresponding argument. Deduction is done as for class templates.
21057 The arguments used in deduction have reference and top level cv
21058 qualifiers removed. Iff both arguments were originally reference
21059 types *and* deduction succeeds in both directions, an lvalue reference
21060 wins against an rvalue reference and otherwise the template
21061 with the more cv-qualified argument wins for that pairing (if
21062 neither is more cv-qualified, they both are equal). Unlike regular
21063 deduction, after all the arguments have been deduced in this way,
21064 we do *not* verify the deduced template argument values can be
21065 substituted into non-deduced contexts.
21067 The logic can be a bit confusing here, because we look at deduce1 and
21068 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21069 can find template arguments for pat1 to make arg1 look like arg2, that
21070 means that arg2 is at least as specialized as arg1. */
21072 int
21074 {
21087 /* Remove the this parameter from non-static member functions. If
21088 one is a non-static member function and the other is not a static
21089 member function, remove the first parameter from that function
21090 also. This situation occurs for operator functions where we
21091 locate both a member function (with this pointer) and non-member
21092 operator (with explicit first operand). */
21094 {
21099 }
21101 {
21104 {
21105 len--;
21107 }
21108 }
21110 /* If only one is a conversion operator, they are unordered. */
21114 /* Consider the return type for a conversion function */
21116 {
21119 len++;
21120 }
21122 processing_template_decl++;
21128 /* Stop when an ellipsis is seen. */
21130 {
21141 {
21142 /* When both arguments are pack expansions, we need only
21143 unify the patterns themselves. */
21147 /* This is the last comparison we need to do. */
21149 }
21152 {
21156 }
21159 {
21163 }
21169 {
21175 /* Setup the parameter vector, which contains only ARG1. */
21178 /* Setup the argument vector, which contains the remaining
21179 arguments. */
21188 /* We cannot deduce in the other direction, because ARG1 is
21189 a pack expansion but ARG2 is not. */
21191 }
21193 {
21199 /* Setup the parameter vector, which contains only ARG1. */
21202 /* Setup the argument vector, which contains the remaining
21203 arguments. */
21212 /* We cannot deduce in the other direction, because ARG2 is
21213 a pack expansion but ARG1 is not.*/
21215 }
21217 else
21218 {
21219 /* The normal case, where neither argument is a pack
21220 expansion. */
21227 }
21229 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21230 arg2, then arg2 is not as specialized as arg1. */
21236 /* "If, for a given type, deduction succeeds in both directions
21237 (i.e., the types are identical after the transformations above)
21238 and both P and A were reference types (before being replaced with
21239 the type referred to above):
21240 - if the type from the argument template was an lvalue reference and
21241 the type from the parameter template was not, the argument type is
21242 considered to be more specialized than the other; otherwise,
21243 - if the type from the argument template is more cv-qualified
21244 than the type from the parameter template (as described above),
21245 the argument type is considered to be more specialized than the other;
21246 otherwise,
21247 - neither type is more specialized than the other." */
21250 {
21252 {
21255 else
21257 }
21259 {
21264 }
21265 }
21268 /* We've failed to deduce something in either direction.
21269 These must be unordered. */
21274 /* We have already processed all of the arguments in our
21275 handing of the pack expansion type. */
21280 }
21282 /* "In most cases, all template parameters must have values in order for
21283 deduction to succeed, but for partial ordering purposes a template
21284 parameter may remain without a value provided it is not used in the
21285 types being used for partial ordering."
21287 Thus, if we are missing any of the targs1 we need to substitute into
21288 origs1, then pat2 is not as specialized as pat1. This can happen when
21289 there is a nondeduced context. */
21295 processing_template_decl--;
21297 /* If both deductions succeed, the partial ordering selects the more
21298 constrained template. */
21300 {
21305 }
21307 /* All things being equal, if the next argument is a pack expansion
21308 for one function but not for the other, prefer the
21309 non-variadic function. FIXME this is bogus; see c++/41958. */
21313 {
21316 }
21322 else
21324 }
21326 /* Determine which of two partial specializations of TMPL is more
21327 specialized.
21329 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21330 to the first partial specialization. The TREE_PURPOSE is the
21331 innermost set of template parameters for the partial
21332 specialization. PAT2 is similar, but for the second template.
21334 Return 1 if the first partial specialization is more specialized;
21335 -1 if the second is more specialized; 0 if neither is more
21336 specialized.
21338 See [temp.class.order] for information about determining which of
21339 two templates is more specialized. */
21341 static int
21343 {
21344 tree targs;
21353 /* Just like what happens for functions, if we are ordering between
21354 different template specializations, we may encounter dependent
21355 types in the arguments, and we need our dependency check functions
21356 to behave correctly. */
21360 {
21363 }
21367 {
21370 }
21373 /* If both deductions succeed, the partial ordering selects the more
21374 constrained template. */
21378 /* In the case of a tie where at least one of the templates
21379 has a parameter pack at the end, the template with the most
21380 non-packed parameters wins. */
21382 && any_deductions
21385 {
21391 /* We don't count the pack expansion at the end. */
21401 }
21404 }
21406 /* Return the template arguments that will produce the function signature
21407 DECL from the function template FN, with the explicit template
21408 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21409 also match. Return NULL_TREE if no satisfactory arguments could be
21410 found. */
21412 static tree
21414 {
21418 tree decl_arg_types;
21421 tree arg;
21425 /* Never do unification on the 'this' parameter. */
21446 }
21448 /* Return the innermost template arguments that, when applied to a partial
21449 specialization SPEC_TMPL of TMPL, yield the ARGS.
21451 For example, suppose we have:
21453 template <class T, class U> struct S {};
21454 template <class T> struct S<T*, int> {};
21456 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21457 partial specialization and the ARGS will be {double*, int}. The resulting
21458 vector will be {double}, indicating that `T' is bound to `double'. */
21460 static tree
21462 {
21464 tree spec_args
21467 tree deduced_args;
21468 tree innermost_deduced_args;
21472 {
21476 innermost_deduced_args);
21477 }
21478 else
21482 again:
21491 {
21493 {
21499 }
21501 }
21505 {
21508 }
21510 /* Verify that nondeduced template arguments agree with the type
21511 obtained from argument deduction.
21513 For example:
21515 struct A { typedef int X; };
21516 template <class T, class U> struct C {};
21517 template <class T> struct C<T, typename T::X> {};
21519 Then with the instantiation `C<A, int>', we can deduce that
21520 `T' is `A' but unify () does not check whether `typename T::X'
21521 is `int'. */
21530 /* We only need to check the innermost arguments; the other
21531 arguments will always agree. */
21536 /* Now that we have bindings for all of the template arguments,
21537 ensure that the arguments deduced for the template template
21538 parameters have compatible template parameter lists. See the use
21539 of template_template_parm_bindings_ok_p in fn_type_unification
21540 for more information. */
21545 }
21547 // Compare two function templates T1 and T2 by deducing bindings
21548 // from one against the other. If both deductions succeed, compare
21549 // constraints to see which is more constrained.
21550 static int
21552 {
21557 {
21560 }
21563 {
21566 }
21568 // If both deductions succeed, then one may be more constrained.
21573 }
21575 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
21576 Return the TREE_LIST node with the most specialized template, if
21577 any. If there is no most specialized template, the error_mark_node
21578 is returned.
21580 Note that this function does not look at, or modify, the
21581 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
21582 returned is one of the elements of INSTANTIATIONS, callers may
21583 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
21584 and retrieve it from the value returned. */
21586 tree
21588 {
21595 {
21600 {
21601 /* Equally specialized, move to next function. If there
21602 is no next function, nothing's most specialized. */
21607 }
21608 }
21611 /* Now verify that champ is better than everything earlier in the
21612 instantiation list. */
21615 {
21618 }
21619 }
21621 processing_template_decl--;
21627 }
21629 /* If DECL is a specialization of some template, return the most
21630 general such template. Otherwise, returns NULL_TREE.
21632 For example, given:
21634 template <class T> struct S { template <class U> void f(U); };
21636 if TMPL is `template <class U> void S<int>::f(U)' this will return
21637 the full template. This function will not trace past partial
21638 specializations, however. For example, given in addition:
21640 template <class T> struct S<T*> { template <class U> void f(U); };
21642 if TMPL is `template <class U> void S<int*>::f(U)' this will return
21643 `template <class T> template <class U> S<T*>::f(U)'. */
21645 tree
21647 {
21649 {
21652 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
21653 template friend, or a FIELD_DECL for a capture pack. */
21656 }
21658 /* Look for more and more general templates. */
21660 {
21661 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
21662 (See cp-tree.h for details.) */
21671 /* Stop if we run into an explicitly specialized class template. */
21678 }
21681 }
21683 /* Return the most specialized of the template partial specializations
21684 which can produce TARGET, a specialization of some class or variable
21685 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
21686 a TEMPLATE_DECL node corresponding to the partial specialization, while
21687 the TREE_PURPOSE is the set of template arguments that must be
21688 substituted into the template pattern in order to generate TARGET.
21690 If the choice of partial specialization is ambiguous, a diagnostic
21691 is issued, and the error_mark_node is returned. If there are no
21692 partial specializations matching TARGET, then NULL_TREE is
21693 returned, indicating that the primary template should be used. */
21695 static tree
21697 {
21699 tree t;
21700 tree champ;
21707 {
21711 }
21713 {
21716 }
21718 {
21722 }
21723 else
21728 /* For determining which partial specialization to use, only the
21729 innermost args are interesting. */
21731 {
21734 }
21737 {
21738 tree spec_args;
21742 {
21743 /* Substitute in the template args from the enclosing class. */
21747 }
21754 {
21758 /* Keep the candidate only if the constraints are satisfied,
21759 or if we're not compiling with concepts. */
21762 {
21765 }
21766 }
21767 }
21777 {
21780 ;
21781 else
21782 {
21784 {
21787 {
21790 }
21791 }
21793 }
21794 }
21798 {
21801 {
21804 }
21805 }
21808 {
21815 else
21819 {
21824 }
21827 }
21830 }
21832 /* Explicitly instantiate DECL. */
21834 void
21836 {
21841 /* An error occurred, for which grokdeclarator has already issued
21842 an appropriate message. */
21845 {
21848 }
21854 {
21855 /* There is an asymmetry here in the way VAR_DECLs and
21856 FUNCTION_DECLs are handled by grokdeclarator. In the case of
21857 the latter, the DECL we get back will be marked as a
21858 template instantiation, and the appropriate
21859 DECL_TEMPLATE_INFO will be set up. This does not happen for
21860 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
21861 should handle VAR_DECLs as it currently handles
21862 FUNCTION_DECLs. */
21864 {
21867 }
21870 {
21873 }
21875 {
21880 }
21881 }
21883 {
21886 }
21887 else
21890 /* Check for various error cases. Note that if the explicit
21891 instantiation is valid the RESULT will currently be marked as an
21892 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
21893 until we get here. */
21896 {
21897 /* DR 259 [temp.spec].
21899 Both an explicit instantiation and a declaration of an explicit
21900 specialization shall not appear in a program unless the explicit
21901 instantiation follows a declaration of the explicit specialization.
21903 For a given set of template parameters, if an explicit
21904 instantiation of a template appears after a declaration of an
21905 explicit specialization for that template, the explicit
21906 instantiation has no effect. */
21908 }
21910 {
21911 /* [temp.spec]
21913 No program shall explicitly instantiate any template more
21914 than once.
21916 We check DECL_NOT_REALLY_EXTERN so as not to complain when
21917 the first instantiation was `extern' and the second is not,
21918 and EXTERN_P for the opposite case. */
21921 /* If an "extern" explicit instantiation follows an ordinary
21922 explicit instantiation, the template is instantiated. */
21925 }
21927 {
21930 }
21932 {
21935 }
21938 ;
21940 {
21943 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
21946 }
21947 else
21955 }
21957 static void
21959 {
21965 {
21968 }
21969 }
21971 /* Called from do_type_instantiation through binding_table_foreach to
21972 do recursive instantiation for the type bound in ENTRY. */
21973 static void
21975 {
21981 }
21983 /* Called from do_type_instantiation to instantiate a member
21984 (a member function or a static member variable) of an
21985 explicitly instantiated class template. */
21986 static void
21988 {
21993 }
21995 /* Perform an explicit instantiation of template class T. STORAGE, if
21996 non-null, is the RID for extern, inline or static. COMPLAIN is
21997 nonzero if this is called from the parser, zero if called recursively,
21998 since the standard is unclear (as detailed below). */
22000 void
22002 {
22012 {
22013 tree tmpl =
22017 else
22020 }
22025 {
22028 t);
22030 }
22033 {
22035 {
22037 {
22040 "ISO C++ 1998 forbids the use of %<extern%> on "
22042 }
22043 else
22045 "ISO C++ forbids the use of %qE"
22047 }
22055 else
22056 {
22058 storage);
22060 }
22061 }
22064 {
22065 /* DR 259 [temp.spec].
22067 Both an explicit instantiation and a declaration of an explicit
22068 specialization shall not appear in a program unless the explicit
22069 instantiation follows a declaration of the explicit specialization.
22071 For a given set of template parameters, if an explicit
22072 instantiation of a template appears after a declaration of an
22073 explicit specialization for that template, the explicit
22074 instantiation has no effect. */
22076 }
22078 {
22079 /* [temp.spec]
22081 No program shall explicitly instantiate any template more
22082 than once.
22084 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22085 instantiation was `extern'. If EXTERN_P then the second is.
22086 These cases are OK. */
22093 /* If we've already instantiated the template, just return now. */
22096 }
22104 {
22105 tree tmp;
22107 /* In contrast to implicit instantiation, where only the
22108 declarations, and not the definitions, of members are
22109 instantiated, we have here:
22111 [temp.explicit]
22113 The explicit instantiation of a class template specialization
22114 implies the instantiation of all of its members not
22115 previously explicitly specialized in the translation unit
22116 containing the explicit instantiation.
22118 Of course, we can't instantiate member template classes, since
22119 we don't have any arguments for them. Note that the standard
22120 is unclear on whether the instantiation of the members are
22121 *explicit* instantiations or not. However, the most natural
22122 interpretation is that it should be an explicit instantiation. */
22138 }
22139 }
22141 /* Given a function DECL, which is a specialization of TMPL, modify
22142 DECL to be a re-instantiation of TMPL with the same template
22143 arguments. TMPL should be the template into which tsubst'ing
22144 should occur for DECL, not the most general template.
22146 One reason for doing this is a scenario like this:
22148 template <class T>
22149 void f(const T&, int i);
22151 void g() { f(3, 7); }
22153 template <class T>
22154 void f(const T& t, const int i) { }
22156 Note that when the template is first instantiated, with
22157 instantiate_template, the resulting DECL will have no name for the
22158 first parameter, and the wrong type for the second. So, when we go
22159 to instantiate the DECL, we regenerate it. */
22161 static void
22163 {
22164 /* The arguments used to instantiate DECL, from the most general
22165 template. */
22166 tree code_pattern;
22170 /* Make sure that we can see identifiers, and compute access
22171 correctly. */
22175 {
22176 tree decl_parm;
22177 tree pattern_parm;
22178 tree specs;
22192 specs);
22194 /* Merge parameter declarations. */
22197 pattern_parm
22201 {
22202 tree parm_type;
22203 tree attributes;
22208 NULL_TREE);
22214 {
22217 }
22220 }
22221 /* Merge any parameters that match with the function parameter
22222 pack. */
22224 {
22226 tree expanded_types;
22227 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22228 the parameters in this function parameter pack. */
22233 {
22234 tree parm_type;
22235 tree attributes;
22238 /* Rename the parameter to include the index. */
22247 {
22250 }
22252 }
22253 }
22254 /* Merge additional specifiers from the CODE_PATTERN. */
22258 }
22260 {
22268 }
22269 else
22273 }
22275 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22276 substituted to get DECL. */
22278 tree
22280 {
22283 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22284 for the instantiation. This is not always the most general
22285 template. Consider, for example:
22287 template <class T>
22288 struct S { template <class U> void f();
22289 template <> void f<int>(); };
22291 and an instantiation of S<double>::f<int>. We want TD to be the
22292 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22294 more general template. */
22296 /* We must also deal with friend templates. Given:
22298 template <class T> struct S {
22299 template <class U> friend void f() {};
22300 };
22302 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22303 so far as the language is concerned, but that's still
22304 where we get the pattern for the instantiation from. On
22305 other hand, if the definition comes outside the class, say:
22307 template <class T> struct S {
22308 template <class U> friend void f();
22309 };
22310 template <class U> friend void f() {}
22312 we don't need to look any further. That's what the check for
22313 DECL_INITIAL is for. */
22317 {
22318 /* The present template, TD, should not be a definition. If it
22319 were a definition, we should be using it! Note that we
22320 cannot restructure the loop to just keep going until we find
22321 a template with a definition, since that might go too far if
22322 a specialization was declared, but not defined. */
22324 /* Fetch the more general template. */
22326 }
22329 }
22331 /* Returns true if we need to instantiate this template instance even if we
22332 know we aren't going to emit it. */
22334 bool
22336 {
22337 /* We always instantiate inline functions so that we can inline them. An
22338 explicit instantiation declaration prohibits implicit instantiation of
22339 non-inline functions. With high levels of optimization, we would
22340 normally inline non-inline functions -- but we're not allowed to do
22341 that for "extern template" functions. Therefore, we check
22342 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22346 /* And we need to instantiate static data members so that
22347 their initializers are available in integral constant
22348 expressions. */
22351 }
22353 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22354 instantiate it now, modifying TREE_TYPE (fn). */
22356 void
22358 {
22361 /* Don't instantiate a noexcept-specification from template context. */
22376 {
22380 {
22395 }
22396 else
22400 }
22403 {
22406 else
22408 }
22409 }
22411 /* Produce the definition of D, a _DECL generated from a template. If
22412 DEFER_OK is true, then we don't have to actually do the
22413 instantiation now; we just have to do it sometime. Normally it is
22414 an error if this is an explicit instantiation but D is undefined.
22415 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22416 instantiated class template. */
22418 tree
22420 {
22422 tree gen_args;
22423 tree args;
22424 tree td;
22425 tree code_pattern;
22426 tree spec;
22427 tree gen_tmpl;
22435 /* This function should only be used to instantiate templates for
22436 functions and static member variables. */
22439 /* A concept is never instantiated. */
22442 /* Variables are never deferred; if instantiation is required, they
22443 are instantiated right away. That allows for better code in the
22444 case that an expression refers to the value of the variable --
22445 if the variable has a constant value the referring expression can
22446 take advantage of that fact. */
22450 /* Don't instantiate cloned functions. Instead, instantiate the
22451 functions they cloned. */
22459 /* D has already been instantiated or explicitly specialized, so
22460 there's nothing for us to do here.
22462 It might seem reasonable to check whether or not D is an explicit
22463 instantiation, and, if so, stop here. But when an explicit
22464 instantiation is deferred until the end of the compilation,
22465 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22466 the instantiation. */
22469 /* Check to see whether we know that this template will be
22470 instantiated in some other file, as with "extern template"
22471 extension. */
22474 /* In general, we do not instantiate such templates. */
22482 /* We should already have the extra args. */
22485 /* And what's in the hash table should match D. */
22489 /* This needs to happen before any tsubsting. */
22495 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
22496 for the instantiation. */
22501 {
22502 /* Look up an explicit specialization, if any. */
22506 {
22509 }
22510 }
22514 /* We should never be trying to instantiate a member of a class
22515 template or partial specialization. */
22520 /* In the case of a friend template whose definition is provided
22521 outside the class, we may have too many arguments. Drop the
22522 ones we don't need. The same is true for specializations. */
22523 args = get_innermost_template_args
22527 {
22533 }
22534 else
22535 {
22540 else
22542 }
22544 /* We may be in the middle of deferred access check. Disable it now. */
22547 /* Unless an explicit instantiation directive has already determined
22548 the linkage of D, remember that a definition is available for
22549 this entity. */
22559 /* If D is a member of an explicitly instantiated class template,
22560 and no definition is available, treat it like an implicit
22561 instantiation. */
22564 {
22565 /* Leave linkage flags alone on instantiations with anonymous
22566 visibility. */
22568 {
22571 }
22573 }
22575 /* Defer all other templates, unless we have been explicitly
22576 forbidden from doing so. */
22578 template. */
22579 ! pattern_defined
22580 /* If it's OK to postpone instantiation, do so. */
22581 || defer_ok
22582 /* If this is a static data member that will be defined
22583 elsewhere, we don't want to instantiate the entire data
22584 member, but we do want to instantiate the initializer so that
22585 we can substitute that elsewhere. */
22587 /* Handle here a deleted function too, avoid generating
22588 its body (c++/61080). */
22590 {
22591 /* The definition of the static data member is now required so
22592 we must substitute the initializer. */
22596 {
22597 tree ns;
22598 tree init;
22607 args,
22610 /* If instantiating the initializer involved instantiating this
22611 again, don't call cp_finish_decl twice. */
22613 {
22614 /* Make sure the initializer is still constant, in case of
22615 circular dependency (template/instantiate6.C). */
22616 const_init
22620 LOOKUP_ONLYCONVERTING);
22621 }
22625 }
22627 /* We restore the source position here because it's used by
22628 add_pending_template. */
22634 /* [temp.explicit]
22636 The definition of a non-exported function template, a
22637 non-exported member function template, or a non-exported
22638 member function or static data member of a class template
22639 shall be present in every translation unit in which it is
22640 explicitly instantiated. */
22644 /* If we're in unevaluated context, we just wanted to get the
22645 constant value; this isn't an odr use, so don't queue
22646 a full instantiation. */
22649 /* ??? Historically, we have instantiated inline functions, even
22650 when marked as "extern template". */
22654 }
22655 /* Tell the repository that D is available in this translation unit
22656 -- and see if it is supposed to be instantiated here. */
22658 {
22659 /* In a PCH file, despite the fact that the repository hasn't
22660 requested instantiation in the PCH it is still possible that
22661 an instantiation will be required in a file that includes the
22662 PCH. */
22665 /* Instantiate inline functions so that the inliner can do its
22666 job, even though we'll not be emitting a copy of this
22667 function. */
22670 }
22673 tree fn_context;
22684 else
22685 {
22689 }
22691 /* Mark D as instantiated so that recursive calls to
22692 instantiate_decl do not try to instantiate it again. */
22695 /* Regenerate the declaration in case the template has been modified
22696 by a subsequent redeclaration. */
22699 /* We already set the file and line above. Reset them now in case
22700 they changed as a result of calling regenerate_decl_from_template. */
22704 {
22705 tree init;
22708 /* Clear out DECL_RTL; whatever was there before may not be right
22709 since we've reset the type of the declaration. */
22713 /* The initializer is placed in DECL_INITIAL by
22714 regenerate_decl_from_template so we don't need to
22715 push/pop_access_scope again here. Pull it out so that
22716 cp_finish_decl can process it. */
22721 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
22722 initializer. That function will defer actual emission until
22723 we have a chance to determine linkage. */
22726 /* Enter the scope of D so that access-checking works correctly. */
22739 }
22743 {
22745 tree tmpl_parm;
22746 tree spec_parm;
22750 /* Save away the current list, in case we are instantiating one
22751 template from within the body of another. */
22754 /* Set up the list of local specializations. */
22757 /* Set up context. */
22761 else
22762 {
22764 {
22765 /* When instantiating a lambda's templated function
22766 operator, we need to push the non-lambda class scope
22767 of the lambda itself so that the nested function
22768 stack is sufficiently correct to deal with this
22769 capture. */
22771 do
22776 }
22778 }
22780 /* Some typedefs referenced from within the template code need to be
22781 access checked at template instantiation time, i.e now. These
22782 types were added to the template at parsing time. Let's get those
22783 and perform the access checks then. */
22785 args);
22787 /* Create substitution entries for the parameters. */
22791 {
22795 }
22797 {
22799 {
22802 }
22803 else
22804 {
22805 /* Register the (value) argument pack as a specialization of
22806 TMPL_PARM, then move on. */
22809 }
22810 }
22813 /* Substitute into the body of the function. */
22817 else
22818 {
22823 /* Set the current input_location to the end of the function
22824 so that finish_function knows where we are. */
22825 input_location
22828 /* Remember if we saw an infinite loop in the template. */
22829 current_function_infinite_loop
22831 }
22833 /* We don't need the local specializations any more. */
22837 /* Finish the function. */
22841 else
22842 {
22845 }
22851 }
22853 /* We're not deferring instantiation any more. */
22858 else
22864 out:
22873 }
22875 /* Run through the list of templates that we wish we could
22876 instantiate, and instantiate any we can. RETRIES is the
22877 number of times we retry pending template instantiation. */
22879 void
22881 {
22885 /* Instantiating templates may trigger vtable generation. This in turn
22886 may require further template instantiations. We place a limit here
22887 to avoid infinite loop. */
22889 {
22893 "template instantiation depth exceeds maximum of %d"
22894 " instantiating %q+D, possibly from virtual table generation"
22898 /* Pretend that we defined it. */
22901 }
22903 do
22904 {
22909 {
22914 {
22915 tree fn;
22918 {
22922 fn;
22930 }
22933 }
22934 else
22935 {
22938 {
22939 instantiation
22945 }
22949 }
22952 /* If INSTANTIATION has been instantiated, then we don't
22953 need to consider it again in the future. */
22955 else
22956 {
22959 }
22962 }
22964 }
22968 }
22970 /* Substitute ARGVEC into T, which is a list of initializers for
22971 either base class or a non-static data member. The TREE_PURPOSEs
22972 are DECLs, and the TREE_VALUEs are the initializer values. Used by
22973 instantiate_decl. */
22975 static tree
22977 {
22981 {
22982 tree decl;
22983 tree init;
22989 {
22990 tree expr;
22991 tree arg;
22993 /* Expand the base class expansion type into separate base
22994 classes. */
22996 tf_warning_or_error,
22997 NULL_TREE);
23001 /* We'll be building separate TREE_LISTs of arguments for
23002 each base. */
23008 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23009 expand each argument in the TREE_VALUE of t. */
23016 /* VOID_TYPE_NODE is used to indicate
23017 value-initialization. */
23018 {
23021 }
23022 else
23023 {
23024 /* Substitute parameter packs into each argument in the
23025 TREE_LIST. */
23028 {
23029 tree expanded_exprs;
23031 /* Expand the argument. */
23033 expanded_exprs
23035 tf_warning_or_error,
23036 NULL_TREE);
23040 /* Prepend each of the expanded expressions to the
23041 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23043 {
23048 }
23049 }
23052 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23053 since we built them backwards. */
23055 {
23058 }
23059 }
23060 }
23063 {
23065 {
23069 }
23070 else
23071 {
23072 tree tmp;
23087 /* If we had an initializer but it instantiated to nothing,
23088 value-initialize the object. This will only occur when
23089 the initializer was a pack expansion where the parameter
23090 packs used in that expansion were of length zero. */
23093 }
23096 {
23100 }
23101 }
23102 }
23104 }
23106 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23108 static void
23110 {
23115 else
23117 }
23119 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23120 is the instantiation (which should have been created with
23121 start_enum) and ARGS are the template arguments to use. */
23123 static void
23125 {
23126 tree e;
23132 {
23133 tree value;
23134 tree decl;
23137 /* Note that in a template enum, the TREE_VALUE is the
23138 CONST_DECL, not the corresponding INTEGER_CST. */
23143 /* Give this enumeration constant the correct access. */
23146 /* Actually build the enumerator itself. Here we're assuming that
23147 enumerators can't have dependent attributes. */
23150 }
23160 }
23162 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23163 its type -- but without substituting the innermost set of template
23164 arguments. So, innermost set of template parameters will appear in
23165 the type. */
23167 tree
23169 {
23170 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23172 }
23174 /* Return truthvalue if we're processing a template different from
23175 the last one involved in diagnostics. */
23176 bool
23178 {
23180 }
23182 /* Remember current template involved in diagnostics. */
23183 void
23185 {
23187 }
23191 {
23193 }
23195 /* Return TRUE if current_function_decl is being instantiated, false
23196 otherwise. */
23198 bool
23200 {
23203 }
23205 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23206 type. Return zero for ok, nonzero for disallowed. Issue error and
23207 warning messages under control of COMPLAIN. */
23209 static int
23211 {
23226 /* A bound template template parm could later be instantiated to have a valid
23227 nontype parm type via an alias template. */
23233 {
23236 else
23238 type);
23239 }
23241 }
23243 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23244 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23246 static bool
23248 {
23249 tree scope;
23251 /* [temp.dep.type]
23253 A type is dependent if it is:
23255 -- a template parameter. Template template parameters are types
23256 for us (since TYPE_P holds true for them) so we handle
23257 them here. */
23261 /* -- a qualified-id with a nested-name-specifier which contains a
23262 class-name that names a dependent type or whose unqualified-id
23263 names a dependent type. */
23267 /* An alias template specialization can be dependent even if the
23268 resulting type is not. */
23272 /* -- a cv-qualified type where the cv-unqualified type is
23273 dependent.
23274 No code is necessary for this bullet; the code below handles
23275 cv-qualified types, and we don't want to strip aliases with
23276 TYPE_MAIN_VARIANT because of DR 1558. */
23277 /* -- a compound type constructed from any dependent type. */
23287 {
23288 tree arg_type;
23293 arg_type;
23298 }
23299 /* -- an array type constructed from any dependent type or whose
23300 size is specified by a constant expression that is
23301 value-dependent.
23303 We checked for type- and value-dependence of the bounds in
23304 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23306 {
23311 }
23313 /* -- a template-id in which either the template name is a template
23314 parameter ... */
23317 /* ... or any of the template arguments is a dependent type or
23318 an expression that is type-dependent or value-dependent. */
23320 && (any_dependent_template_arguments_p
23324 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23325 dependent; if the argument of the `typeof' expression is not
23326 type-dependent, then it should already been have resolved. */
23332 /* A template argument pack is dependent if any of its packed
23333 arguments are. */
23335 {
23341 }
23343 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23344 be template parameters. */
23351 /* The standard does not specifically mention types that are local
23352 to template functions or local classes, but they should be
23353 considered dependent too. For example:
23355 template <int I> void f() {
23356 enum E { a = I };
23357 S<sizeof (E)> s;
23358 }
23360 The size of `E' cannot be known until the value of `I' has been
23361 determined. Therefore, `E' must be considered dependent. */
23365 /* Don't use type_dependent_expression_p here, as it can lead
23366 to infinite recursion trying to determine whether a lambda
23367 nested in a lambda is dependent (c++/47687). */
23371 && (any_dependent_template_arguments_p
23375 /* Other types are non-dependent. */
23377 }
23379 /* Returns TRUE if TYPE is dependent, in the sense of
23380 [temp.dep.type]. Note that a NULL type is considered dependent. */
23382 bool
23384 {
23385 /* If there are no template parameters in scope, then there can't be
23386 any dependent types. */
23388 {
23389 /* If we are not processing a template, then nobody should be
23390 providing us with a dependent type. */
23394 }
23396 /* If the type is NULL, we have not computed a type for the entity
23397 in question; in that case, the type is dependent. */
23401 /* Erroneous types can be considered non-dependent. */
23405 /* If we have not already computed the appropriate value for TYPE,
23406 do so now. */
23408 {
23411 }
23414 }
23416 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23417 lookup. In other words, a dependent type that is not the current
23418 instantiation. */
23420 bool
23422 {
23425 }
23427 /* T is a SCOPE_REF; return whether we need to consider it
23428 instantiation-dependent so that we can check access at instantiation
23429 time even though we know which member it resolves to. */
23431 static bool
23433 {
23439 else
23441 }
23443 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23444 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23445 expression. */
23447 /* Note that this predicate is not appropriate for general expressions;
23448 only constant expressions (that satisfy potential_constant_expression)
23449 can be tested for value dependence. */
23451 bool
23453 {
23457 /* A name declared with a dependent type. */
23462 {
23464 /* A dependent member function of the current instantiation. */
23468 /* A dependent member function of the current instantiation. */
23475 /* A name that has not been looked up -- must be dependent. */
23479 /* A non-type template parm. */
23483 /* A non-type template parm. */
23489 /* A constant with literal type and is initialized
23490 with an expression that is value-dependent.
23492 Note that a non-dependent parenthesized initializer will have
23493 already been replaced with its constant value, so if we see
23494 a TREE_LIST it must be dependent. */
23498 /* cp_finish_decl doesn't fold reference initializers. */
23510 /* These expressions are value-dependent if the type to which
23511 the cast occurs is dependent or the expression being casted
23512 is value-dependent. */
23513 {
23519 /* A functional cast has a list of operands. */
23522 {
23523 /* If there are no operands, it must be an expression such
23524 as "int()". This should not happen for aggregate types
23525 because it would form non-constant expressions. */
23530 }
23536 }
23541 /* FALLTHRU */
23544 /* A `sizeof' expression is value-dependent if the operand is
23545 type-dependent or is a pack expansion. */
23554 /* An 'encode' expression is value-dependent if the operand is
23555 type-dependent. */
23564 /* All instantiation-dependent expressions should also be considered
23565 value-dependent. */
23573 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
23574 is value-dependent. */
23575 {
23584 }
23587 {
23591 }
23602 {
23606 }
23609 /* Treat all requires-expressions as value-dependent so
23610 we don't try to fold them. */
23617 {
23624 {
23626 /* In a call to a constexpr member function, look through the
23627 implicit ADDR_EXPR on the object argument so that it doesn't
23628 cause the call to be considered value-dependent. We also
23629 look through it in potential_constant_expression. */
23636 }
23638 }
23641 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
23642 type-dependent. */
23647 {
23649 tree val;
23656 }
23659 /* Treat a GNU statement expression as dependent to avoid crashing
23660 under instantiate_non_dependent_expr; it can't be constant. */
23664 /* A constant expression is value-dependent if any subexpression is
23665 value-dependent. */
23667 {
23674 {
23678 {
23681 /* In some cases, some of the operands may be missing.l
23682 (For example, in the case of PREDECREMENT_EXPR, the
23683 amount to increment by may be missing.) That doesn't
23684 make the expression dependent. */
23687 }
23688 }
23692 }
23694 }
23696 /* The expression is not value-dependent. */
23698 }
23700 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
23701 [temp.dep.expr]. Note that an expression with no type is
23702 considered dependent. Other parts of the compiler arrange for an
23703 expression with type-dependent subexpressions to have no type, so
23704 this function doesn't have to be fully recursive. */
23706 bool
23708 {
23715 /* An unresolved name is always dependent. */
23721 /* A fold expression is type-dependent. */
23728 /* Some expression forms are never type-dependent. */
23742 /* The types of these expressions depends only on the type to which
23743 the cast occurs. */
23752 /* The types of these expressions depends only on the type created
23753 by the expression. */
23756 {
23757 /* For NEW_EXPR tree nodes created inside a template, either
23758 the object type itself or a TREE_LIST may appear as the
23759 operand 1. */
23762 /* This is an array type. We need to check array dimensions
23763 as well. */
23765 || value_dependent_expression_p
23767 else
23769 }
23772 {
23776 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
23777 contains an identifier associated by name lookup with one or more
23778 declarations declared with a dependent type, or...a
23779 nested-name-specifier or qualified-id that names a member of an
23780 unknown specialization. */
23783 }
23793 {
23794 tree elt;
23798 {
23801 }
23803 }
23805 /* A static data member of the current instantiation with incomplete
23806 array type is type-dependent, as the definition and specializations
23807 can have different bounds. */
23814 /* An array of unknown bound depending on a variadic parameter, eg:
23816 template<typename... Args>
23817 void foo (Args... args)
23818 {
23819 int arr[] = { args... };
23820 }
23822 template<int... vals>
23823 void bar ()
23824 {
23825 int arr[] = { vals... };
23826 }
23828 If the array has no length and has an initializer, it must be that
23829 we couldn't determine its length in cp_complete_array_type because
23830 it is dependent. */
23837 /* A function or variable template-id is type-dependent if it has any
23838 dependent template arguments. Note that we only consider the innermost
23839 template arguments here, since those are the ones that come from the
23840 template-id; the template arguments for the enclosing class do not make it
23841 type-dependent, they only make a member function value-dependent. */
23846 && (any_dependent_template_arguments_p
23850 /* Always dependent, on the number of arguments if nothing else. */
23855 {
23860 {
23866 }
23867 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
23872 {
23877 }
23880 {
23887 }
23893 {
23897 }
23899 }
23903 /* Dependent type attributes might not have made it from the decl to
23904 the type yet. */
23910 }
23912 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
23913 type-dependent if the expression refers to a member of the current
23914 instantiation and the type of the referenced member is dependent, or the
23915 class member access expression refers to a member of an unknown
23916 specialization.
23918 This function returns true if the OBJECT in such a class member access
23919 expression is of an unknown specialization. */
23921 bool
23923 {
23926 }
23928 /* walk_tree callback function for instantiation_dependent_expression_p,
23929 below. Returns non-zero if a dependent subexpression is found. */
23931 static tree
23934 {
23936 {
23937 /* We don't have to worry about decltype currently because decltype
23938 of an instantiation-dependent expr is a dependent type. This
23939 might change depending on the resolution of DR 1172. */
23942 }
23945 {
23946 /* Don't treat an argument list as dependent just because it has no
23947 TREE_TYPE. */
23955 /* Handle expressions with type operands. */
23960 {
23965 {
23968 else
23969 {
23972 }
23973 }
23975 }
23979 /* In a template, finish_class_member_access_expr creates a
23980 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
23981 type-dependent, so that we can check access control at
23982 instantiation time (PR 42277). See also Core issue 1273. */
23989 else
23992 /* Treat statement-expressions as dependent. */
23996 /* Treat requires-expressions as dependent. */
24001 /* Treat calls to function concepts as dependent. */
24007 /* And variable concepts. */
24014 }
24018 else
24020 }
24022 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24023 sense defined by the ABI:
24025 "An expression is instantiation-dependent if it is type-dependent
24026 or value-dependent, or it has a subexpression that is type-dependent
24027 or value-dependent."
24029 Except don't actually check value-dependence for unevaluated expressions,
24030 because in sizeof(i) we don't care about the value of i. Checking
24031 type-dependence will in turn check value-dependence of array bounds/template
24032 arguments as needed. */
24034 bool
24036 {
24037 tree result;
24048 }
24050 /* As above, but also check value-dependence of the expression as a whole. */
24052 bool
24054 {
24057 }
24059 /* Like type_dependent_expression_p, but it also works while not processing
24060 a template definition, i.e. during substitution or mangling. */
24062 bool
24064 {
24070 }
24072 /* Returns TRUE if ARGS contains a type-dependent expression. */
24074 bool
24076 {
24078 tree arg;
24081 {
24084 }
24086 }
24088 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24089 expressions) contains any type-dependent expressions. */
24091 bool
24093 {
24099 }
24101 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24102 expressions) contains any value-dependent expressions. */
24104 bool
24106 {
24112 }
24114 /* Returns TRUE if the ARG (a template argument) is dependent. */
24116 bool
24118 {
24122 /* Assume a template argument that was wrongly written by the user
24123 is dependent. This is consistent with what
24124 any_dependent_template_arguments_p [that calls this function]
24125 does. */
24135 {
24138 /* A member template of a dependent class is not necessarily
24139 type-dependent, but it is a dependent template argument because it
24140 will be a member of an unknown specialization to that template. */
24143 }
24145 {
24149 {
24152 }
24155 }
24158 else
24161 }
24163 /* Returns true if ARGS (a collection of template arguments) contains
24164 any types that require structural equality testing. */
24166 bool
24168 {
24178 {
24181 {
24187 {
24188 /* Look inside the argument pack. */
24191 }
24194 {
24207 }
24208 }
24209 }
24212 }
24214 /* Returns true if ARGS (a collection of template arguments) contains
24215 any dependent arguments. */
24217 bool
24219 {
24229 {
24234 }
24237 }
24239 /* Returns TRUE if the template TMPL is type-dependent. */
24241 bool
24243 {
24245 {
24247 {
24251 }
24253 }
24255 /* Template template parameters are dependent. */
24259 /* So are names that have not been looked up. */
24263 }
24265 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24267 bool
24269 {
24272 }
24274 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24275 are dependent. */
24277 bool
24279 {
24286 {
24308 {
24312 }
24316 {
24320 {
24325 }
24326 }
24327 }
24330 }
24332 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24333 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24334 no such TYPE can be found. Note that this function peers inside
24335 uninstantiated templates and therefore should be used only in
24336 extremely limited situations. ONLY_CURRENT_P restricts this
24337 peering to the currently open classes hierarchy (which is required
24338 when comparing types). */
24340 tree
24342 {
24343 tree scope;
24344 tree name;
24345 tree decl;
24347 tree pushed_scope;
24348 tree result;
24353 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24354 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24355 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24356 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24357 identifier of the TYPENAME_TYPE anymore.
24358 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24359 TYPENAME_TYPE instead, we avoid messing up with a possible
24360 typedef variant case. */
24363 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24364 it first before we can figure out what NAME refers to. */
24366 {
24368 /* Given a class template A with a dependent base with nested type C,
24369 typedef typename A::C::C C will land us here, as trying to resolve
24370 the initial A::C leads to the local C typedef, which leads back to
24371 A::C::C. So we break the recursion now. */
24373 else
24375 }
24376 /* If we don't know what SCOPE refers to, then we cannot resolve the
24377 TYPENAME_TYPE. */
24380 /* If this is a typedef, we don't want to look inside (c++/11987). */
24383 /* If SCOPE isn't the template itself, it will not have a valid
24384 TYPE_FIELDS list. */
24386 /* scope is either the template itself or a compatible instantiation
24387 like X<T>, so look up the name in the original template. */
24389 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24391 /* If scope has no fields, it can't be a current instantiation. Check this
24392 before currently_open_class to avoid infinite recursion (71515). */
24395 /* If the SCOPE is not the current instantiation, there's no reason
24396 to look inside it. */
24399 /* Enter the SCOPE so that name lookup will be resolved as if we
24400 were in the class definition. In particular, SCOPE will no
24401 longer be considered a dependent type. */
24403 /* Look up the declaration. */
24405 tf_warning_or_error);
24409 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24410 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24415 {
24419 }
24422 {
24423 tree tmpl;
24424 tree args;
24425 /* Obtain the template and the arguments. */
24428 /* Instantiate the template. */
24434 }
24436 /* Leave the SCOPE. */
24440 /* If we failed to resolve it, return the original typename. */
24444 /* If lookup found a typename type, resolve that too. */
24446 {
24447 /* Ill-formed programs can cause infinite recursion here, so we
24448 must catch that. */
24452 }
24454 /* Qualify the resulting type. */
24460 }
24462 /* EXPR is an expression which is not type-dependent. Return a proxy
24463 for EXPR that can be used to compute the types of larger
24464 expressions containing EXPR. */
24466 tree
24468 {
24469 tree inner_expr;
24471 /* When checking, try to get a constant value for all non-dependent
24472 expressions in order to expose bugs in *_dependent_expression_p
24473 and constexpr. This can affect code generation, see PR70704, so
24474 only do this for -fchecking=2. */
24477 /* Don't do this during nsdmi parsing as it can lead to
24478 unexpected recursive instantiations. */
24480 /* Don't do this during concept expansion either and for
24481 the same reason. */
24485 /* Preserve OVERLOADs; the functions must be available to resolve
24486 types. */
24497 /* There is no need to return a proxy for a variable. */
24500 /* Preserve string constants; conversions from string constants to
24501 "char *" are allowed, even though normally a "const char *"
24502 cannot be used to initialize a "char *". */
24505 /* Preserve void and arithmetic constants, as an optimization -- there is no
24506 reason to create a new node. */
24511 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
24512 There is at least one place where we want to know that a
24513 particular expression is a throw-expression: when checking a ?:
24514 expression, there are special rules if the second or third
24515 argument is a throw-expression. */
24519 /* Don't wrap an initializer list, we need to be able to look inside. */
24523 /* Don't wrap a dummy object, we need to be able to test for it. */
24542 /* If the type is unknown, it can't really be non-dependent */
24545 /* Otherwise, build a NON_DEPENDENT_EXPR. */
24547 }
24549 /* ARGS is a vector of expressions as arguments to a function call.
24550 Replace the arguments with equivalent non-dependent expressions.
24551 This modifies ARGS in place. */
24553 void
24555 {
24557 tree arg;
24560 {
24564 }
24565 }
24567 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
24568 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
24569 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
24571 static tree
24573 {
24587 }
24589 tree
24591 {
24593 }
24595 tree
24597 {
24599 }
24601 /* Return a C++17 deduction placeholder for class template TMPL. */
24603 tree
24605 {
24609 }
24611 /* Make a "constrained auto" type-specifier. This is an
24612 auto type with constraints that must be associated after
24613 deduction. The constraint is formed from the given
24614 CONC and its optional sequence of arguments, which are
24615 non-null if written as partial-concept-id. */
24617 tree
24619 {
24622 /* Build the constraint. */
24624 tree expr;
24627 else
24633 /* Our canonical type depends on the constraint. */
24636 /* Attach the constraint to the type declaration. */
24639 }
24641 /* Given type ARG, return std::initializer_list<ARG>. */
24643 static tree
24645 {
24646 tree std_init_list = namespace_binding
24648 tree argvec;
24650 {
24654 }
24659 }
24661 /* Replace auto in TYPE with std::initializer_list<auto>. */
24663 static tree
24665 {
24672 }
24674 /* Hash traits for hashing possibly constrained 'auto'
24675 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
24678 {
24681 };
24683 /* Hash the 'auto' T. */
24685 inline hashval_t
24687 {
24689 /* Matching constrained-type-specifiers denote the same template
24690 parameter, so hash the constraint. */
24692 else
24693 /* But unconstrained autos are all separate, so just hash the pointer. */
24695 }
24697 /* Compare two 'auto's. */
24701 {
24708 /* Two unconstrained autos are distinct. */
24713 }
24715 /* for_each_template_parm callback for extract_autos: if t is a (possibly
24716 constrained) auto, add it to the vector. */
24718 static int
24720 {
24723 {
24724 /* All the autos were built with index 0; fix that up now. */
24728 /* If this is a repeated constrained-type-specifier, use the index we
24729 chose before. */
24731 else
24732 {
24733 /* Otherwise this is new, so use the current count. */
24736 }
24738 }
24740 /* Always keep walking. */
24742 }
24744 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
24745 says they can appear anywhere in the type. */
24747 static tree
24749 {
24758 {
24763 }
24766 }
24768 /* The stem for deduction guide names. */
24771 /* Return the name for a deduction guide for class template TMPL. */
24773 tree
24775 {
24786 }
24788 /* True if NAME is the name of a deduction guide. */
24790 bool
24792 {
24796 }
24798 /* True if FN is a deduction guide. */
24800 bool
24802 {
24807 }
24809 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
24810 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
24811 template parameter types. Note that the handling of template template
24812 parameters relies on current_template_parms being set appropriately for the
24813 new template. */
24815 static tree
24818 {
24821 tree newtype;
24824 {
24831 }
24832 else
24836 tree newdecl
24841 tree newidx;
24844 {
24852 {
24857 // First create a copy (ttargs) of tsubst_args with an
24858 // additional level for the template template parameter's own
24859 // template parameters (ttparms).
24860 tree ttparms = (INNERMOST_TEMPLATE_PARMS
24868 // Substitute ttargs into ttparms to fix references to
24869 // other template parameters.
24871 complain);
24872 // Now substitute again with args based on tparms, to reduce
24873 // the level of the ttparms.
24876 complain);
24877 // Finally, tack the adjusted parms onto tparms.
24879 current_template_parms);
24881 }
24882 }
24883 else
24884 {
24886 tree newconst
24896 }
24901 }
24903 /* Returns a C++17 class deduction guide template based on the constructor
24904 CTOR. */
24906 static tree
24908 {
24912 tree fn_tmpl;
24914 {
24917 }
24918 else
24922 /* If type is a member class template, DECL_TI_ARGS (ctor) will have fully
24923 specialized args for the enclosing class. Strip those off, as the
24924 deduction guide won't have those template parameters. */
24927 /* Discard the 'this' parameter. */
24933 {
24934 /* For a member template constructor, we need to flatten the two template
24935 parameter lists into one, and then adjust the function signature
24936 accordingly. This gets...complicated. */
24940 /* For a member template we should have two levels of parms/args, one for
24941 the class and one for the constructor. We stripped specialized args
24942 for further enclosing classes above. */
24946 /* Template args for translating references to the two-level template
24947 parameters into references to the one-level template parameters we are
24948 creating. */
24953 /* Template parms for the constructor template. */
24956 /* Template parms for the class template. */
24960 /* Template parms for the deduction guide start as a copy of the template
24961 parms for the class. We set current_template_parms for
24962 lookup_template_class_1. */
24968 /* Now we need to rewrite the constructor parms to append them to the
24969 class parms. */
24971 {
24986 }
24988 /* Now we have a final set of template parms to substitute into the
24989 function signature. */
24999 }
25000 else
25001 {
25002 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25006 }
25010 FUNCTION_DECL,
25024 }
25026 /* Deduce template arguments for the class template placeholder PTYPE for
25027 template TMPL based on the initializer INIT, and return the resulting
25028 type. */
25030 tree
25032 {
25034 {
25035 /* We should have handled this in the caller. */
25041 }
25050 else
25054 {
25055 /* First try to deduce directly, since we don't have implicitly-declared
25056 constructors yet. */
25065 }
25077 {
25080 }
25083 // FIXME cache artificial deduction guides
25085 {
25089 }
25092 {
25096 }
25105 }
25107 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25108 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25110 tree
25112 {
25114 tf_warning_or_error,
25115 adc_unspecified);
25116 }
25118 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25119 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25120 The CONTEXT determines the context in which auto deduction is performed
25121 and is used to control error diagnostics.
25123 For partial-concept-ids, extra args may be appended to the list of deduced
25124 template arguments prior to determining constraint satisfaction. */
25126 tree
25129 tree outer_targs)
25130 {
25131 tree targs;
25138 /* Defining a subset of type-dependent expressions that we can deduce
25139 from ahead of time isn't worth the trouble. */
25143 /* C++17 class template argument deduction. */
25146 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25147 with either a new invented type template parameter U or, if the
25148 initializer is a braced-init-list (8.5.4), with
25149 std::initializer_list<U>. */
25151 {
25156 else
25157 {
25159 {
25163 "for deduction to %<std::initializer_list%>, use copy-"
25165 }
25167 }
25168 }
25179 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25180 and initializer has array type, deduce cv-qualified array type. */
25182 complain);
25184 {
25193 {
25197 }
25198 }
25199 else
25200 {
25202 tree tparms;
25206 else
25207 {
25211 }
25218 {
25220 /* Try again at instantiation time. */
25224 /* If type is error_mark_node a diagnostic must have been
25225 emitted by now. Also, having a mention to '<type error>'
25226 in the diagnostic is not really useful to the user. */
25227 {
25231 else
25236 }
25238 }
25239 }
25241 /* Check any placeholder constraints against the deduced type. */
25244 {
25245 /* Use the deduced type to check the associated constraints. If we
25246 have a partial-concept-id, rebuild the argument list so that
25247 we check using the extra arguments. */
25251 {
25254 }
25255 else
25258 {
25260 {
25262 {
25280 }
25282 }
25284 }
25285 }
25291 }
25293 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
25294 result. */
25296 tree
25298 {
25300 {
25306 /* In an abbreviated function template we didn't know we were dealing
25307 with a function template when we saw the auto return type, so update
25308 it to have the correct level. */
25310 }
25312 }
25314 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
25315 'decltype(auto)' or a deduced class template. */
25317 bool
25319 {
25325 else
25327 }
25329 /* for_each_template_parm callback for type_uses_auto. */
25331 int
25333 {
25335 }
25337 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
25338 a use of `auto'. Returns NULL_TREE otherwise. */
25340 tree
25342 {
25346 {
25347 /* The Concepts TS allows multiple autos in one type-specifier; just
25348 return the first one we find, do_auto_deduction will collect all of
25349 them. */
25353 else
25355 }
25356 else
25358 }
25360 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
25361 'decltype(auto)' or a concept. */
25363 bool
25365 {
25367 }
25369 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
25370 a concept identifier) iff TYPE contains a use of a generic type. Returns
25371 NULL_TREE otherwise. */
25373 tree
25375 {
25377 }
25380 /* For a given template T, return the vector of typedefs referenced
25381 in T for which access check is needed at T instantiation time.
25382 T is either a FUNCTION_DECL or a RECORD_TYPE.
25383 Those typedefs were added to T by the function
25384 append_type_to_template_for_access_check. */
25388 {
25389 tree ti;
25400 {
25405 }
25408 }
25410 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
25411 tied to T. That list of typedefs will be access checked at
25412 T instantiation time.
25413 T is either a FUNCTION_DECL or a RECORD_TYPE.
25414 TYPE_DECL is a TYPE_DECL node representing a typedef.
25415 SCOPE is the scope through which TYPE_DECL is accessed.
25416 LOCATION is the location of the usage point of TYPE_DECL.
25418 This function is a subroutine of
25419 append_type_to_template_for_access_check. */
25421 static void
25423 tree type_decl,
25424 tree scope,
25425 location_t location)
25426 {
25427 qualified_typedef_usage_t typedef_usage;
25428 tree ti;
25435 && type_decl
25449 }
25451 /* Append TYPE_DECL to the template TEMPL.
25452 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
25453 At TEMPL instanciation time, TYPE_DECL will be checked to see
25454 if it can be accessed through SCOPE.
25455 LOCATION is the location of the usage point of TYPE_DECL.
25457 e.g. consider the following code snippet:
25459 class C
25460 {
25461 typedef int myint;
25462 };
25464 template<class U> struct S
25465 {
25466 C::myint mi; // <-- usage point of the typedef C::myint
25467 };
25469 S<char> s;
25471 At S<char> instantiation time, we need to check the access of C::myint
25472 In other words, we need to check the access of the myint typedef through
25473 the C scope. For that purpose, this function will add the myint typedef
25474 and the scope C through which its being accessed to a list of typedefs
25475 tied to the template S. That list will be walked at template instantiation
25476 time and access check performed on each typedefs it contains.
25477 Note that this particular code snippet should yield an error because
25478 myint is private to C. */
25480 void
25482 tree type_decl,
25483 tree scope,
25484 location_t location)
25485 {
25491 /* Make sure we don't append the type to the template twice. */
25498 }
25500 /* Convert the generic type parameters in PARM that match the types given in the
25501 range [START_IDX, END_IDX) from the current_template_parms into generic type
25502 packs. */
25504 tree
25506 {
25517 {
25518 /* Create a distinct parameter pack type from the current parm and add it
25519 to the replacement args to tsubst below into the generic function
25520 parameter. */
25535 }
25541 /* If there are more levels then build up the replacement with the outer
25542 template parms. */
25546 replacement);
25549 }
25551 /* Entries in the decl_constraint hash table. */
25553 {
25554 tree decl;
25555 tree ci;
25556 };
25558 /* Hashing function and equality for constraint entries. */
25560 {
25562 {
25564 }
25567 {
25569 }
25570 };
25572 /* A mapping from declarations to constraint information. Note that
25573 both templates and their underlying declarations are mapped to the
25574 same constraint information.
25576 FIXME: This is defined in pt.c because garbage collection
25577 code is not being generated for constraint.cc. */
25581 /* Returns the template constraints of declaration T. If T is not
25582 constrained, return NULL_TREE. Note that T must be non-null. */
25584 tree
25586 {
25597 else
25599 }
25601 /* Associate the given constraint information CI with the declaration
25602 T. If T is a template, then the constraints are associated with
25603 its underlying declaration. Don't build associations if CI is
25604 NULL_TREE. */
25606 void
25608 {
25620 }
25622 /* Remove the associated constraints of the declaration T. */
25624 void
25626 {
25635 }
25637 /* Memoized satisfaction results for declarations. This
25638 maps the pair (constraint_info, arguments) to the result computed
25639 by constraints_satisfied_p. */
25642 {
25643 tree ci;
25644 tree args;
25645 tree result;
25646 };
25648 /* Hashing function and equality for constraint entries. */
25651 {
25653 {
25656 }
25659 {
25661 }
25662 };
25664 /* Memoized satisfaction results for concept checks. */
25667 {
25668 tree tmpl;
25669 tree args;
25670 tree result;
25671 };
25673 /* Hashing function and equality for constraint entries. */
25676 {
25678 {
25680 }
25683 {
25688 }
25689 };
25694 /* Search for a memoized satisfaction result. Returns one of the
25695 truth value nodes if previously memoized, or NULL_TREE otherwise. */
25697 tree
25699 {
25704 else
25706 }
25708 /* Memoize the result of a satisfication test. Returns the saved result. */
25710 tree
25712 {
25719 }
25721 /* Search for a memoized satisfaction result for a concept. */
25723 tree
25725 {
25730 else
25732 }
25734 /* Memoize the result of a concept check. Returns the saved result. */
25736 tree
25738 {
25745 }
25749 /* Returns a prior concept specialization. This returns the substituted
25750 and normalized constraints defined by the concept. */
25752 tree
25754 {
25759 else
25761 }
25763 /* Save a concept expansion for later. */
25765 tree
25767 {
25774 }
25776 static hashval_t
25778 {
25787 }
25789 /* Compare the constraints of two subsumption entries. The LEFT1 and
25790 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
25791 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
25793 static bool
25795 {
25803 }
25805 /* Key/value pair for learning and memoizing subsumption results. This
25806 associates a pair of check constraints (including arguments) with
25807 a boolean value indicating the result. */
25810 {
25811 tree t1;
25812 tree t2;
25814 };
25816 /* Hashing function and equality for constraint entries. */
25819 {
25821 {
25823 }
25826 {
25831 }
25832 };
25836 /* Search for a previously cached subsumption result. */
25840 {
25845 else
25847 }
25849 /* Save a subsumption result. */
25851 bool
25853 {
25860 }
25862 /* Set up the hash table for constraint association. */
25864 void
25866 {
25875 }
25877 /* Set up the hash tables for template instantiations. */
25879 void
25881 {
25884 }
25886 /* Print stats about the template hash tables for -fstats. */
25888 void
25890 {
25899 }