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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
46 /* The type of functions taking a tree, and some additional data, and
47 returning an int. */
50 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
51 instantiations have been deferred, either because their definitions
52 were not yet available, or because we were putting off doing the work. */
54 {
57 };
72 /* Live only within one (recursive) call to tsubst_expr. We use
73 this to pass the statement expression node from the STMT_EXPR
74 to the EXPR_STMT that is its result. */
77 // -------------------------------------------------------------------------- //
78 // Local Specialization Stack
79 //
80 // Implementation of the RAII helper for creating new local
81 // specializations.
84 {
87 else
89 }
92 {
95 }
97 /* True if we've recursed into fn_type_unification too many times. */
101 {
102 tree tmpl;
103 tree args;
104 tree spec;
105 };
108 {
111 };
117 /* Contains canonical template parameter types. The vector is indexed by
118 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
119 TREE_LIST, whose TREE_VALUEs contain the canonical template
120 parameters of various types and levels. */
123 #define UNIFY_ALLOW_NONE 0
124 #define UNIFY_ALLOW_MORE_CV_QUAL 1
125 #define UNIFY_ALLOW_LESS_CV_QUAL 2
126 #define UNIFY_ALLOW_DERIVED 4
127 #define UNIFY_ALLOW_INTEGER 8
128 #define UNIFY_ALLOW_OUTER_LEVEL 16
129 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
130 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
133 tbr_incomplete_type,
134 tbr_ambiguous_baseclass,
135 tbr_success
136 };
161 tree);
218 location_t);
230 /* Make the current scope suitable for access checking when we are
231 processing T. T can be FUNCTION_DECL for instantiated function
232 template, VAR_DECL for static member variable, or TYPE_DECL for
233 alias template (needed by instantiate_decl). */
235 static void
237 {
245 else
249 {
250 saved_access_scope = tree_cons
253 }
254 }
256 /* Restore the scope set up by push_access_scope. T is the node we
257 are processing. */
259 static void
261 {
263 {
266 }
270 else
272 }
274 /* Do any processing required when DECL (a member template
275 declaration) is finished. Returns the TEMPLATE_DECL corresponding
276 to DECL, unless it is a specialization, in which case the DECL
277 itself is returned. */
279 tree
281 {
288 {
289 tree type;
297 {
301 }
303 }
307 {
309 {
312 }
313 else
315 }
316 else
320 }
322 /* Create a template info node. */
324 tree
326 {
331 }
333 /* Return the template info node corresponding to T, whatever T is. */
335 tree
337 {
359 }
361 /* Returns the template nesting level of the indicated class TYPE.
363 For example, in:
364 template <class T>
365 struct A
366 {
367 template <class U>
368 struct B {};
369 };
371 A<T>::B<U> has depth two, while A<T> has depth one.
372 Both A<T>::B<int> and A<int>::B<U> have depth one, if
373 they are instantiations, not specializations.
375 This function is guaranteed to return 0 if passed NULL_TREE so
376 that, for example, `template_class_depth (current_class_type)' is
377 always safe. */
379 int
381 {
385 {
396 else
398 }
401 }
403 /* Subroutine of maybe_begin_member_template_processing.
404 Returns true if processing DECL needs us to push template parms. */
406 static bool
408 {
414 }
416 /* Subroutine of maybe_begin_member_template_processing.
417 Push the template parms in PARMS, starting from LEVELS steps into the
418 chain, and ending at the beginning, since template parms are listed
419 innermost first. */
421 static void
423 {
431 current_template_parms
437 NULL);
439 {
448 {
455 /* Push the CONST_DECL. */
461 }
462 }
463 }
465 /* Restore the template parameter context for a member template, a
466 friend template defined in a class definition, or a non-template
467 member of template class. */
469 void
471 {
472 tree parms;
477 {
480 /* Disregard full specializations (c++/60999). */
483 }
486 {
491 {
494 }
497 }
499 /* Remember how many levels of template parameters we pushed so that
500 we can pop them later. */
502 }
504 /* Undo the effects of maybe_begin_member_template_processing. */
506 void
508 {
517 {
521 }
522 }
524 /* Return a new template argument vector which contains all of ARGS,
525 but has as its innermost set of arguments the EXTRA_ARGS. */
527 static tree
529 {
530 tree new_args;
548 }
550 /* Like add_to_template_args, but only the outermost ARGS are added to
551 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
552 (EXTRA_ARGS) levels are added. This function is used to combine
553 the template arguments from a partial instantiation with the
554 template arguments used to attain the full instantiation from the
555 partial instantiation. */
557 static tree
559 {
560 tree new_args;
562 /* If there are more levels of EXTRA_ARGS than there are ARGS,
563 something very fishy is going on. */
566 /* If *all* the new arguments will be the EXTRA_ARGS, just return
567 them. */
571 /* For the moment, we make ARGS look like it contains fewer levels. */
576 /* Now, we restore ARGS to its full dimensions. */
580 }
582 /* Return the N levels of innermost template arguments from the ARGS. */
584 tree
586 {
587 tree new_args;
593 /* If N is 1, just return the innermost set of template arguments. */
597 /* If we're not removing anything, just return the arguments we were
598 given. */
604 /* Make a new set of arguments, not containing the outer arguments. */
611 }
613 /* The inverse of get_innermost_template_args: Return all but the innermost
614 EXTRA_LEVELS levels of template arguments from the ARGS. */
616 static tree
618 {
619 tree new_args;
625 /* If N is 1, just return the outermost set of template arguments. */
629 /* If we're not removing anything, just return the arguments we were
630 given. */
635 /* Make a new set of arguments, not containing the inner arguments. */
642 }
644 /* We've got a template header coming up; push to a new level for storing
645 the parms. */
647 void
649 {
650 /* We use a non-tag-transparent scope here, which causes pushtag to
651 put tags in this scope, rather than in the enclosing class or
652 namespace scope. This is the right thing, since we want
653 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
654 global template class, push_template_decl handles putting the
655 TEMPLATE_DECL into top-level scope. For a nested template class,
656 e.g.:
658 template <class T> struct S1 {
659 template <class T> struct S2 {};
660 };
662 pushtag contains special code to insert the TEMPLATE_DECL for S2
663 at the right scope. */
669 /* Add a dummy parameter level while we process the parameter list. */
670 current_template_parms
673 current_template_parms);
674 }
676 /* This routine is called when a specialization is declared. If it is
677 invalid to declare a specialization here, an error is reported and
678 false is returned, otherwise this routine will return true. */
680 static bool
682 {
685 /* [temp.expl.spec]
687 An explicit specialization shall be declared in the namespace of
688 which the template is a member, or, for member templates, in the
689 namespace of which the enclosing class or enclosing class
690 template is a member. An explicit specialization of a member
691 function, member class or static data member of a class template
692 shall be declared in the namespace of which the class template
693 is a member. */
695 {
698 }
700 /* [temp.expl.spec]
702 In an explicit specialization declaration for a member of a class
703 template or a member template that appears in namespace scope,
704 the member template and some of its enclosing class templates may
705 remain unspecialized, except that the declaration shall not
706 explicitly specialize a class member template if its enclosing
707 class templates are not explicitly specialized as well. */
709 {
712 }
715 }
717 /* We've just seen template <>. */
719 bool
721 {
725 }
727 /* Called at then end of processing a declaration preceded by
728 template<>. */
730 void
732 {
735 }
737 /* Any template <>'s that we have seen thus far are not referring to a
738 function specialization. */
740 void
742 {
745 }
747 /* We've just seen a template header. If SPECIALIZATION is nonzero,
748 it was of the form template <>. */
750 static void
752 {
754 template_header_count++;
755 }
757 /* We're beginning an explicit instantiation. */
759 void
761 {
764 }
767 void
769 {
772 }
774 /* An explicit specialization or partial specialization of TMPL is being
775 declared. Check that the namespace in which the specialization is
776 occurring is permissible. Returns false iff it is invalid to
777 specialize TMPL in the current namespace. */
779 static bool
781 {
784 /* [tmpl.expl.spec]
786 An explicit specialization shall be declared in a namespace enclosing the
787 specialized template. An explicit specialization whose declarator-id is
788 not qualified shall be declared in the nearest enclosing namespace of the
789 template, or, if the namespace is inline (7.3.1), any namespace from its
790 enclosing namespace set. */
793 {
796 }
799 /* Same or enclosing namespace. */
801 else
802 {
808 }
809 }
811 /* SPEC is an explicit instantiation. Check that it is valid to
812 perform this explicit instantiation in the current namespace. */
814 static void
816 {
817 tree ns;
819 /* DR 275: An explicit instantiation shall appear in an enclosing
820 namespace of its template. */
826 }
828 // Returns the type of a template specialization only if that
829 // specialization needs to be defined. Otherwise (e.g., if the type has
830 // already been defined), the function returns NULL_TREE.
831 static tree
833 {
834 // An implicit instantiation of an incomplete type implies
835 // the definition of a new class template.
836 //
837 // template<typename T>
838 // struct S;
839 //
840 // template<typename T>
841 // struct S<T*>;
842 //
843 // Here, S<T*> is an implicit instantiation of S whose type
844 // is incomplete.
848 // It can also be the case that TYPE is a completed specialization.
849 // Continuing the previous example, suppose we also declare:
850 //
851 // template<typename T>
852 // requires Integral<T>
853 // struct S<T*>;
854 //
855 // Here, S<T*> refers to the specialization S<T*> defined
856 // above. However, we need to differentiate definitions because
857 // we intend to define a new partial specialization. In this case,
858 // we rely on the fact that the constraints are different for
859 // this declaration than that above.
860 //
861 // Note that we also get here for injected class names and
862 // late-parsed template definitions. We must ensure that we
863 // do not create new type declarations for those cases.
865 {
869 // If there are no template parameters, this cannot be a new
870 // partial template specializtion?
874 // The injected-class-name is not a new partial specialization.
878 // If the constraints are not the same as those of the primary
879 // then, we can probably create a new specialization.
883 {
887 }
889 // Also, if there's a pre-existing specialization with matching
890 // constraints, then this also isn't new.
893 {
901 }
903 // Create a new type node (and corresponding type decl)
904 // for the newly declared specialization.
909 /* We only need a separate type node for storing the definition of this
910 partial specialization; uses of S<T*> are unconstrained, so all are
911 equivalent. So keep TYPE_CANONICAL the same. */
914 // Build the corresponding type decl.
920 }
923 }
925 /* The TYPE is being declared. If it is a template type, that means it
926 is a partial specialization. Do appropriate error-checking. */
928 tree
930 {
931 tree context;
936 /* A lambda that appears in specialization context is not itself a
937 specialization. */
942 {
946 }
951 {
957 else
960 }
962 {
963 /* This is for ordinary explicit specialization and partial
964 specialization of a template class such as:
966 template <> class C<int>;
968 or:
970 template <class T> class C<T*>;
972 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
975 {
982 {
987 }
988 }
994 /* Trying to define a specialization either without a template<> header
995 or in an inappropriate place. We've already given an error, so just
996 bail now so we don't actually define the specialization. */
998 }
1004 {
1005 /* This is for an explicit specialization of member class
1006 template according to [temp.expl.spec/18]:
1008 template <> template <class U> class C<int>::D;
1010 The context `C<int>' must be an implicit instantiation.
1011 Otherwise this is just a member class template declared
1012 earlier like:
1014 template <> class C<int> { template <class U> class D; };
1015 template <> template <class U> class C<int>::D;
1017 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1018 while in the second case, `C<int>::D' is a primary template
1019 and `C<T>::D' may not exist. */
1023 {
1024 tree t;
1029 {
1034 }
1036 /* Check for invalid specialization after instantiation:
1038 template <> template <> class C<int>::D<int>;
1039 template <> template <class U> class C<int>::D; */
1043 {
1047 {
1048 /* We already have a full specialization of this partial
1049 instantiation, or a full specialization has been
1050 looked up but not instantiated. Reassign it to the
1051 new member specialization template. */
1052 spec_entry elt;
1064 spec_entry **slot
1069 }
1070 else
1071 /* But if we've had an implicit instantiation, that's a
1072 problem ([temp.expl.spec]/6). */
1075 }
1077 /* Mark TYPE as a specialization. And as a result, we only
1078 have one level of template argument for the innermost
1079 class template. */
1084 }
1085 }
1087 {
1088 /* Someday C++0x may allow for enum template specialization. */
1093 else
1094 {
1097 }
1098 }
1101 }
1103 /* Returns nonzero if we can optimize the retrieval of specializations
1104 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1105 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1109 {
1112 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1113 parameter. */
1115 /* The optimized lookup depends on the fact that the
1116 template arguments for the member function template apply
1117 purely to the containing class, which is not true if the
1118 containing class is an explicit or partial
1119 specialization. */
1123 /* It is possible to have a template that is not a member
1124 template and is not a member of a template class:
1126 template <typename T>
1127 struct S { friend A::f(); };
1129 Here, the friend function is a template, but the context does
1130 not have template information. The optimized lookup relies
1131 on having ARGS be the template arguments for both the class
1132 and the function template. */
1134 }
1136 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1137 gone through coerce_template_parms by now. */
1139 static void
1141 {
1143 {
1152 /* Allow typedefs on the type of a non-type argument, since a
1154 else
1156 }
1157 }
1159 static void
1161 {
1166 }
1168 /* Retrieve the specialization (in the sense of [temp.spec] - a
1169 specialization is either an instantiation or an explicit
1170 specialization) of TMPL for the given template ARGS. If there is
1171 no such specialization, return NULL_TREE. The ARGS are a vector of
1172 arguments, or a vector of vectors of arguments, in the case of
1173 templates with more than one level of parameters.
1175 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1176 then we search for a partial specialization matching ARGS. This
1177 parameter is ignored if TMPL is not a class template.
1179 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1180 result is a NONTYPE_ARGUMENT_PACK. */
1182 static tree
1184 {
1194 /* There should be as many levels of arguments as there are
1195 levels of parameters. */
1204 /* Lambda functions in templates aren't instantiated normally, but through
1205 tsubst_lambda_expr. */
1210 {
1211 /* The template arguments actually apply to the containing
1212 class. Find the class specialization with those
1213 arguments. */
1215 tree class_specialization
1220 /* Find the instance of TMPL. */
1223 {
1226 /* using-declarations can add base methods to the method vec,
1227 and we don't want those here. */
1230 }
1232 }
1233 else
1234 {
1236 spec_entry elt;
1245 else
1253 }
1256 }
1258 /* Like retrieve_specialization, but for local declarations. */
1260 tree
1262 {
1268 }
1270 /* Returns nonzero iff DECL is a specialization of TMPL. */
1272 int
1274 {
1275 tree t;
1278 {
1284 }
1285 else
1286 {
1295 }
1298 }
1300 /* Returns nonzero iff DECL is a specialization of friend declaration
1301 FRIEND_DECL according to [temp.friend]. */
1303 bool
1305 {
1312 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1313 of a template class, we want to check if DECL is a specialization
1314 if this. */
1318 {
1319 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1322 }
1327 /* There is nothing to do if this is not a template friend. */
1334 /* [temp.friend/6]
1335 A member of a class template may be declared to be a friend of a
1336 non-template class. In this case, the corresponding member of
1337 every specialization of the class template is a friend of the
1338 class granting friendship.
1340 For example, given a template friend declaration
1342 template <class T> friend void A<T>::f();
1344 the member function below is considered a friend
1346 template <> struct A<int> {
1347 void f();
1348 };
1350 For this type of template friend, TEMPLATE_DEPTH below will be
1351 nonzero. To determine if DECL is a friend of FRIEND, we first
1352 check if the enclosing class is a specialization of another. */
1359 {
1360 /* Next, we check the members themselves. In order to handle
1361 a few tricky cases, such as when FRIEND_DECL's are
1363 template <class T> friend void A<T>::g(T t);
1364 template <class T> template <T t> friend void A<T>::h();
1366 and DECL's are
1368 void A<int>::g(int);
1369 template <int> void A<int>::h();
1371 we need to figure out ARGS, the template arguments from
1372 the context of DECL. This is required for template substitution
1373 of `T' in the function parameter of `g' and template parameter
1374 of `h' in the above examples. Here ARGS corresponds to `int'. */
1381 {
1383 {
1386 else
1388 current_depth++;
1389 }
1391 }
1394 {
1396 tree friend_type;
1397 tree decl_type;
1398 tree friend_args_type;
1399 tree decl_args_type;
1401 /* Make sure that both DECL and FRIEND_DECL are templates or
1402 non-templates. */
1408 {
1409 /* If both are templates, check template parameter list. */
1410 tree friend_parms
1415 friend_parms))
1419 }
1420 else
1428 /* Check if return types match. */
1432 /* Check if function parameter types match, ignoring the
1433 `this' parameter. */
1442 }
1443 else
1444 {
1445 /* DECL is a TYPE_DECL */
1449 /* Make sure that both DECL and FRIEND_DECL are templates or
1450 non-templates. */
1451 is_template
1458 {
1459 tree friend_parms;
1460 /* If both are templates, check the name of the two
1461 TEMPLATE_DECL's first because is_friend didn't. */
1466 /* Now check template parameter list. */
1467 friend_parms
1470 return comp_template_parms
1472 friend_parms);
1473 }
1474 else
1477 }
1478 }
1480 }
1482 /* Register the specialization SPEC as a specialization of TMPL with
1483 the indicated ARGS. IS_FRIEND indicates whether the specialization
1484 is actually just a friend declaration. ATTRLIST is the list of
1485 attributes that the specialization is declared with or NULL when
1486 it isn't. Returns SPEC, or an equivalent prior declaration, if
1487 available.
1489 We also store instantiations of field packs in the hash table, even
1490 though they are not themselves templates, to make lookup easier. */
1492 static tree
1494 hashval_t hash)
1495 {
1496 tree fn;
1498 spec_entry elt;
1506 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1507 register it; we want the corresponding TEMPLATE_DECL instead.
1508 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1509 the more obvious `uses_template_parms (spec)' to avoid problems
1510 with default function arguments. In particular, given
1511 something like this:
1513 template <class T> void f(T t1, T t = T())
1515 the default argument expression is not substituted for in an
1516 instantiation unless and until it is actually needed. */
1520 /* We don't put these specializations in the hash table, but we might
1521 want to give an error about a mismatch. */
1523 else
1524 {
1532 slot =
1536 else
1538 }
1540 /* We can sometimes try to re-register a specialization that we've
1541 already got. In particular, regenerate_decl_from_template calls
1542 duplicate_decls which will update the specialization list. But,
1543 we'll still get called again here anyhow. It's more convenient
1544 to simply allow this than to try to prevent it. */
1548 {
1550 {
1553 {
1555 fn);
1557 }
1558 else
1559 {
1560 tree clone;
1561 /* This situation should occur only if the first
1562 specialization is an implicit instantiation, the
1563 second is an explicit specialization, and the
1564 implicit instantiation has not yet been used. That
1565 situation can occur if we have implicitly
1566 instantiated a member function and then specialized
1567 it later.
1569 We can also wind up here if a friend declaration that
1570 looked like an instantiation turns out to be a
1571 specialization:
1573 template <class T> void foo(T);
1574 class S { friend void foo<>(int) };
1575 template <> void foo(int);
1577 We transform the existing DECL in place so that any
1578 pointers to it become pointers to the updated
1579 declaration.
1581 If there was a definition for the template, but not
1582 for the specialization, we want this to look as if
1583 there were no definition, and vice versa. */
1586 /* The call to duplicate_decls will have applied
1587 [temp.expl.spec]:
1589 An explicit specialization of a function template
1590 is inline only if it is explicitly declared to be,
1591 and independently of whether its function template
1592 is.
1594 to the primary function; now copy the inline bits to
1595 the various clones. */
1597 {
1604 }
1608 }
1609 }
1611 {
1614 /* We've already complained in duplicate_decls. */
1618 /* Dup decl failed, but this is a new definition. Set the
1619 line number so any errors match this new
1620 definition. */
1624 }
1625 }
1629 /* A specialization must be declared in the same namespace as the
1630 template it is specializing. */
1636 {
1645 /* If TMPL is a forward declaration of a template function, keep a list
1646 of all specializations in case we need to reassign them to a friend
1647 template later in tsubst_friend_function.
1649 Also keep a list of all variable template instantiations so that
1650 process_partial_specialization can check whether a later partial
1651 specialization would have used it. */
1654 }
1657 }
1659 /* Returns true iff two spec_entry nodes are equivalent. */
1663 bool
1665 {
1672 /* tmpl could be a FIELD_DECL for a capture pack. */
1676 {
1677 /* Partial specializations of a variable template can be distinguished by
1678 constraints. */
1682 }
1686 }
1688 /* Returns a hash for a template TMPL and template arguments ARGS. */
1690 static hashval_t
1692 {
1695 }
1697 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1698 ignoring SPEC. */
1700 hashval_t
1702 {
1704 }
1706 /* Recursively calculate a hash value for a template argument ARG, for use
1707 in the hash tables of template specializations. */
1709 hashval_t
1711 {
1731 {
1739 {
1744 }
1766 {
1770 {
1773 }
1775 }
1779 {
1782 }
1793 val = iterative_hash_template_arg
1805 val);
1807 val);
1816 /* A lambda can't appear in a template arg, but don't crash on
1817 erroneous input. */
1829 /* Now hash operands as usual. */
1834 }
1837 {
1840 {
1841 // We want an alias specialization that survived strip_typedefs
1842 // to hash differently from its TYPE_CANONICAL, to avoid hash
1843 // collisions that compare as different in template_args_equal.
1844 // These could be dependent specializations that strip_typedefs
1845 // left alone, or untouched specializations because
1846 // coerce_template_parms returns the unconverted template
1847 // arguments if it sees incomplete argument packs.
1850 }
1853 val);
1856 /* Otherwise just compare the types during lookup. */
1865 {
1870 }
1871 }
1874 }
1876 /* Unregister the specialization SPEC as a specialization of TMPL.
1877 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1878 if the SPEC was listed as a specialization of TMPL.
1880 Note that SPEC has been ggc_freed, so we can't look inside it. */
1882 bool
1884 {
1886 spec_entry elt;
1894 {
1899 }
1902 }
1904 /* Like register_specialization, but for local declarations. We are
1905 registering SPEC, an instantiation of TMPL. */
1907 void
1909 {
1912 }
1914 /* TYPE is a class type. Returns true if TYPE is an explicitly
1915 specialized class. */
1917 bool
1919 {
1923 }
1925 /* Print the list of functions at FNS, going through all the overloads
1926 for each element of the list. Alternatively, FNS can not be a
1927 TREE_LIST, in which case it will be printed together with all the
1928 overloads.
1930 MORE and *STR should respectively be FALSE and NULL when the function
1931 is called from the outside. They are used internally on recursive
1932 calls. print_candidates manages the two parameters and leaves NULL
1933 in *STR when it ends. */
1935 static void
1937 {
1941 else
1943 {
1949 {
1952 else
1955 }
1957 }
1958 }
1960 /* Print the list of candidate FNS in an error message. FNS can also
1961 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1963 void
1965 {
1969 }
1971 /* Get a (possibly) constrained template declaration for the
1972 purpose of ordering candidates. */
1973 static tree
1975 {
1981 }
1983 /* Among candidates having the same signature, return the
1984 most constrained or NULL_TREE if there is no best candidate.
1985 If the signatures of candidates vary (e.g., template
1986 specialization vs. member function), then there can be no
1987 most constrained.
1989 Note that we don't compare constraints on the functions
1990 themselves, but rather those of their templates. */
1991 static tree
1993 {
1994 // Try to find the best candidate in a first pass.
1997 {
2004 }
2006 // Verify that the champ is better than previous candidates.
2011 }
2014 }
2017 /* Returns the template (one of the functions given by TEMPLATE_ID)
2018 which can be specialized to match the indicated DECL with the
2019 explicit template args given in TEMPLATE_ID. The DECL may be
2020 NULL_TREE if none is available. In that case, the functions in
2021 TEMPLATE_ID are non-members.
2023 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2024 specialization of a member template.
2026 The TEMPLATE_COUNT is the number of references to qualifying
2027 template classes that appeared in the name of the function. See
2028 check_explicit_specialization for a more accurate description.
2030 TSK indicates what kind of template declaration (if any) is being
2031 declared. TSK_TEMPLATE indicates that the declaration given by
2032 DECL, though a FUNCTION_DECL, has template parameters, and is
2033 therefore a template function.
2035 The template args (those explicitly specified and those deduced)
2036 are output in a newly created vector *TARGS_OUT.
2038 If it is impossible to determine the result, an error message is
2039 issued. The error_mark_node is returned to indicate failure. */
2041 static tree
2043 tree decl,
2047 tmpl_spec_kind tsk)
2048 {
2049 tree fns;
2050 tree targs;
2051 tree explicit_targs;
2054 /* A TREE_LIST of templates of which DECL may be a specialization.
2055 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2056 corresponding TREE_PURPOSE is the set of template arguments that,
2057 when used to instantiate the template, would produce a function
2058 with the signature of DECL. */
2068 /* We shouldn't be specializing a member template of an
2069 unspecialized class template; we already gave an error in
2070 check_specialization_scope, now avoid crashing. */
2074 {
2077 }
2085 /* Check for baselinks. */
2090 {
2093 }
2095 {
2098 }
2100 /* Count the number of template headers specified for this
2101 specialization. */
2111 {
2114 tf_warning_or_error,
2118 }
2120 {
2124 {
2125 tree decl_arg_types;
2126 tree fn_arg_types;
2127 tree insttype;
2129 /* In case of explicit specialization, we need to check if
2130 the number of template headers appearing in the specialization
2131 is correct. This is usually done in check_explicit_specialization,
2132 but the check done there cannot be exhaustive when specializing
2133 member functions. Consider the following code:
2135 template <> void A<int>::f(int);
2136 template <> template <> void A<int>::f(int);
2138 Assuming that A<int> is not itself an explicit specialization
2139 already, the first line specializes "f" which is a non-template
2140 member function, whilst the second line specializes "f" which
2141 is a template member function. So both lines are syntactically
2142 correct, and check_explicit_specialization does not reject
2143 them.
2145 Here, we can do better, as we are matching the specialization
2146 against the declarations. We count the number of template
2147 headers, and we check if they match TEMPLATE_COUNT + 1
2148 (TEMPLATE_COUNT is the number of qualifying template classes,
2149 plus there must be another header for the member template
2150 itself).
2152 Notice that if header_count is zero, this is not a
2153 specialization but rather a template instantiation, so there
2154 is no check we can perform here. */
2158 /* Check that the number of template arguments at the
2159 innermost level for DECL is the same as for FN. */
2167 /* DECL might be a specialization of FN. */
2171 /* For a non-static member function, we need to make sure
2172 that the const qualification is the same. Since
2173 get_bindings does not try to merge the "this" parameter,
2174 we must do the comparison explicitly. */
2176 {
2181 /* And the ref-qualification. */
2185 }
2187 /* Skip the "this" parameter and, for constructors of
2188 classes with virtual bases, the VTT parameter. A
2189 full specialization of a constructor will have a VTT
2190 parameter, but a template never will. */
2191 decl_arg_types
2193 fn_arg_types
2196 /* Function templates cannot be specializations; there are
2197 no partial specializations of functions. Therefore, if
2198 the type of DECL does not match FN, there is no
2199 match.
2201 Note that it should never be the case that we have both
2202 candidates added here, and for regular member functions
2203 below. */
2205 {
2209 }
2211 /* See whether this function might be a specialization of this
2212 template. Suppress access control because we might be trying
2213 to make this specialization a friend, and we have already done
2214 access control for the declaration of the specialization. */
2220 /* We cannot deduce template arguments that when used to
2221 specialize TMPL will produce DECL. */
2225 /* We deduced something involving 'auto', which isn't a valid
2226 template argument. */
2229 /* Remove, from the set of candidates, all those functions
2230 whose constraints are not satisfied. */
2234 // Then, try to form the new function type.
2238 fn_arg_types
2243 /* Save this template, and the arguments deduced. */
2245 }
2247 /* FN is an ordinary member function, and we need a
2248 specialization of a member template. */
2249 ;
2251 /* We can get IDENTIFIER_NODEs here in certain erroneous
2252 cases. */
2253 ;
2255 /* This is just an ordinary non-member function. Nothing can
2256 be a specialization of that. */
2257 ;
2259 /* Cannot specialize functions that are created implicitly. */
2260 ;
2261 else
2262 {
2263 tree decl_arg_types;
2265 /* This is an ordinary member function. However, since
2266 we're here, we can assume its enclosing class is a
2267 template class. For example,
2269 template <typename T> struct S { void f(); };
2270 template <> void S<int>::f() {}
2272 Here, S<int>::f is a non-template, but S<int> is a
2273 template class. If FN has the same type as DECL, we
2274 might be in business. */
2277 /* Its enclosing class is an explicit specialization
2278 of a template class. This is not a candidate. */
2283 /* The return types differ. */
2286 /* Adjust the type of DECL in case FN is a static member. */
2293 decl_arg_types))
2301 // If the deduced arguments do not satisfy the constraints,
2302 // this is not a candidate.
2306 // Add the candidate.
2308 }
2309 }
2312 {
2313 /* We have:
2315 [temp.expl.spec]
2317 It is possible for a specialization with a given function
2318 signature to be instantiated from more than one function
2319 template. In such cases, explicit specification of the
2320 template arguments must be used to uniquely identify the
2321 function template specialization being specialized.
2323 Note that here, there's no suggestion that we're supposed to
2324 determine which of the candidate templates is most
2325 specialized. However, we, also have:
2327 [temp.func.order]
2329 Partial ordering of overloaded function template
2330 declarations is used in the following contexts to select
2331 the function template to which a function template
2332 specialization refers:
2334 -- when an explicit specialization refers to a function
2335 template.
2337 So, we do use the partial ordering rules, at least for now.
2338 This extension can only serve to make invalid programs valid,
2339 so it's safe. And, there is strong anecdotal evidence that
2340 the committee intended the partial ordering rules to apply;
2341 the EDG front end has that behavior, and John Spicer claims
2342 that the committee simply forgot to delete the wording in
2343 [temp.expl.spec]. */
2346 {
2349 }
2350 }
2352 // Concepts allows multiple declarations of member functions
2353 // with the same signature. Like above, we need to rely on
2354 // on the partial ordering of those candidates to determine which
2355 // is the best.
2357 {
2359 {
2362 }
2363 }
2366 {
2373 else
2376 }
2380 {
2386 }
2388 /* We have one, and exactly one, match. */
2390 {
2394 // Propagate the candidate's constraints to the declaration.
2397 /* DECL is a re-declaration or partial instantiation of a template
2398 function. */
2401 /* It was a specialization of an ordinary member function in a
2402 template class. */
2404 }
2406 /* It was a specialization of a template. */
2409 {
2414 }
2415 else
2418 }
2420 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2421 but with the default argument values filled in from those in the
2422 TMPL_TYPES. */
2424 static tree
2426 tree tmpl_types)
2427 {
2428 tree new_spec_types;
2436 /* Substitute into the rest of the list. */
2437 new_spec_types =
2441 /* Add the default argument for this parameter. */
2444 new_spec_types);
2445 }
2447 /* DECL is an explicit specialization. Replicate default arguments
2448 from the template it specializes. (That way, code like:
2450 template <class T> void f(T = 3);
2451 template <> void f(double);
2452 void g () { f (); }
2454 works, as required.) An alternative approach would be to look up
2455 the correct default arguments at the call-site, but this approach
2456 is consistent with how implicit instantiations are handled. */
2458 static void
2460 {
2461 tree tmpl;
2462 tree spec_types;
2463 tree tmpl_types;
2464 tree new_spec_types;
2465 tree old_type;
2466 tree new_type;
2467 tree t;
2472 /* See if there's anything we need to do. */
2485 {
2486 /* Remove the this pointer, but remember the object's type for
2487 CV quals. */
2493 {
2494 /* DECL may contain more parameters than TMPL due to the extra
2495 in-charge parameter in constructors and destructors. */
2498 }
2500 {
2503 }
2504 }
2506 /* Compute the merged default arguments. */
2507 new_spec_types =
2510 /* Compute the new FUNCTION_TYPE. */
2512 {
2516 new_spec_types);
2519 /* Put the in-charge parameter back. */
2522 new_spec_types);
2526 new_spec_types);
2527 }
2528 else
2530 new_spec_types);
2536 }
2538 /* Return the number of template headers we expect to see for a definition
2539 or specialization of CTYPE or one of its non-template members. */
2541 int
2543 {
2547 {
2548 /* You're supposed to have one `template <...>' for every
2549 template class, but you don't need one for a full
2550 specialization. For example:
2552 template <class T> struct S{};
2553 template <> struct S<int> { void f(); };
2554 void S<int>::f () {}
2556 is correct; there shouldn't be a `template <>' for the
2557 definition of `S<int>::f'. */
2559 /* If CTYPE does not have template information of any
2560 kind, then it is not a template, nor is it nested
2561 within a template. */
2569 }
2572 }
2574 /* Do a simple sanity check on the template headers that precede the
2575 variable declaration DECL. */
2577 void
2579 {
2584 {
2587 "variable templates only available with "
2590 // Namespace-scope variable templates should have a template header.
2592 }
2594 {
2596 "too many template headers for %qD "
2602 "members of an explicitly specialized class are defined "
2604 }
2605 }
2607 /* An explicit specialization whose declarator-id or class-head-name is not
2608 qualified shall be declared in the nearest enclosing namespace of the
2609 template, or, if the namespace is inline (7.3.1), any namespace from its
2610 enclosing namespace set.
2612 If the name declared in the explicit instantiation is an unqualified name,
2613 the explicit instantiation shall appear in the namespace where its template
2614 is declared or, if that namespace is inline (7.3.1), any namespace from its
2615 enclosing namespace set. */
2617 void
2619 {
2624 {
2630 /* This was allowed in C++98, so only pedwarn. */
2632 "outside its namespace must use a nested-name-"
2634 }
2635 }
2637 /* Warn for a template specialization SPEC that is missing some of a set
2638 of function or type attributes that the template TEMPL is declared with.
2639 ATTRLIST is a list of additional attributes that SPEC should be taken
2640 to ultimately be declared with. */
2642 static void
2644 {
2651 /* Avoid warning if either declaration or its type is deprecated. */
2673 /* Avoid warning if the primary has no attributes. */
2677 /* Avoid warning if either declaration contains an attribute on
2678 the white list below. */
2681 };
2689 /* Avoid warning if the difference between the primary and
2690 the specialization is not in one of the attributes below. */
2694 };
2696 /* Put together a list of the black listed attributes that the primary
2697 template is declared with that the specialization is not, in case
2698 it's not apparent from the most recent declaration of the primary. */
2700 pretty_printer str;
2703 {
2705 {
2710 {
2720 }
2721 }
2722 }
2729 spec))
2735 }
2737 /* Check to see if the function just declared, as indicated in
2738 DECLARATOR, and in DECL, is a specialization of a function
2739 template. We may also discover that the declaration is an explicit
2740 instantiation at this point.
2742 Returns DECL, or an equivalent declaration that should be used
2743 instead if all goes well. Issues an error message if something is
2744 amiss. Returns error_mark_node if the error is not easily
2745 recoverable.
2747 FLAGS is a bitmask consisting of the following flags:
2749 2: The function has a definition.
2750 4: The function is a friend.
2752 The TEMPLATE_COUNT is the number of references to qualifying
2753 template classes that appeared in the name of the function. For
2754 example, in
2756 template <class T> struct S { void f(); };
2757 void S<int>::f();
2759 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2760 classes are not counted in the TEMPLATE_COUNT, so that in
2762 template <class T> struct S {};
2763 template <> struct S<int> { void f(); }
2764 template <> void S<int>::f();
2766 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2767 invalid; there should be no template <>.)
2769 If the function is a specialization, it is marked as such via
2770 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2771 is set up correctly, and it is added to the list of specializations
2772 for that template. */
2774 tree
2776 tree decl,
2779 tree attrlist)
2780 {
2789 tmpl_spec_kind tsk;
2792 {
2795 else
2797 }
2798 else
2802 {
2805 {
2808 }
2810 {
2812 /* This could be something like:
2814 template <class T> void f(T);
2815 class S { friend void f<>(int); } */
2817 else
2818 {
2819 /* This case handles bogus declarations like template <>
2820 template <class T> void f<int>(); */
2823 declarator);
2825 }
2826 }
2830 /* The error has already been reported in
2831 check_specialization_scope. */
2837 /* Fall through. */
2850 decl);
2853 else
2857 /* Fall through. */
2863 /* In cases like template<> constexpr bool v = true;
2864 We'll give an error in check_template_variable. */
2870 else
2876 {
2877 /* This case handles bogus declarations like template <>
2878 template <class T> void f<int>(); */
2882 declarator);
2884 {
2885 /* Partial specialization of variable template. */
2889 }
2893 else
2897 ok:;
2898 }
2901 /* This is a specialization of a member template, without
2902 specialization the containing class. Something like:
2904 template <class T> struct S {
2905 template <class U> void f (U);
2906 };
2907 template <> template <class U> void S<int>::f(U) {}
2909 That's a specialization -- but of the entire template. */
2915 }
2918 /* This doesn't apply to variable templates. */
2921 {
2925 {
2929 }
2930 }
2933 {
2938 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2940 {
2941 tree fns;
2946 else
2947 {
2948 /* If there is no class context, the explicit instantiation
2949 must be at namespace scope. */
2952 /* Find the namespace binding, using the declaration
2953 context. */
2957 /* If lookup fails, look for a friend declaration so we can
2958 give a better diagnostic. */
2964 {
2967 }
2968 }
2971 }
2977 {
2979 /* A specialization in class scope. This is invalid,
2980 but the error will already have been flagged by
2981 check_specialization_scope. */
2983 else
2984 {
2985 /* It's not valid to write an explicit instantiation in
2986 class scope, e.g.:
2988 class C { template void f(); }
2990 This case is caught by the parser. However, on
2991 something like:
2993 template class C { void f(); };
2995 (which is invalid) we can get here. The error will be
2996 issued later. */
2997 ;
2998 }
3001 }
3004 {
3005 // We'll match variable templates in start_decl.
3009 /* Find the list of functions in ctype that have the same
3010 name as the declared function. */
3014 {
3018 {
3019 /* From [temp.expl.spec]:
3021 If such an explicit specialization for the member
3022 of a class template names an implicitly-declared
3023 special member function (clause _special_), the
3024 program is ill-formed.
3026 Similar language is found in [temp.explicit]. */
3029 }
3032 }
3034 /* For a type-conversion operator, We might be looking for
3035 `operator int' which will be a specialization of
3036 `operator T'. Grab all the conversion operators, and
3037 then select from them. */
3042 {
3045 }
3046 else
3048 }
3050 /* Figure out what exactly is being specialized at this point.
3051 Note that for an explicit instantiation, even one for a
3052 member function, we cannot tell a priori whether the
3053 instantiation is for a member template, or just a member
3054 function of a template class. Even if a member template is
3055 being instantiated, the member template arguments may be
3056 elided if they can be deduced from the rest of the
3057 declaration. */
3060 member_specialization,
3061 template_count,
3062 tsk);
3065 /* We couldn't figure out what this declaration was
3066 specializing. */
3068 else
3069 {
3072 {
3074 "friend declaration %qD is not visible to "
3078 }
3086 {
3087 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3088 is done by do_decl_instantiation later. */
3094 {
3095 /* If TMPL is not the most general template (for
3096 example, if TMPL is a friend template that is
3097 injected into namespace scope), then there will
3098 be too many levels of TARGS. Remove some of them
3099 here. */
3101 tree new_targs;
3108 }
3111 }
3113 /* If we thought that the DECL was a member function, but it
3114 turns out to be specializing a static member function,
3115 make DECL a static member function as well. */
3121 /* If this is a specialization of a member template of a
3122 template class, we want to return the TEMPLATE_DECL, not
3123 the specialization of it. */
3125 {
3130 {
3131 tree parm;
3135 /* We want to use the argument list specified in the
3136 definition, not in the original declaration. */
3141 }
3144 }
3146 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3152 /* Inherit default function arguments from the template
3153 DECL is specializing. */
3157 /* This specialization has the same protection as the
3158 template it specializes. */
3162 /* 7.1.1-1 [dcl.stc]
3164 A storage-class-specifier shall not be specified in an
3165 explicit specialization...
3167 The parser rejects these, so unless action is taken here,
3168 explicit function specializations will always appear with
3169 global linkage.
3171 The action recommended by the C++ CWG in response to C++
3172 defect report 605 is to make the storage class and linkage
3173 of the explicit specialization match the templated function:
3175 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3176 */
3178 {
3182 /* A concept cannot be specialized. */
3184 {
3186 gen_tmpl);
3188 }
3190 /* This specialization has the same linkage and visibility as
3191 the function template it specializes. */
3194 {
3197 }
3200 {
3203 }
3204 }
3206 /* If DECL is a friend declaration, declared using an
3207 unqualified name, the namespace associated with DECL may
3208 have been set incorrectly. For example, in:
3210 template <typename T> void f(T);
3211 namespace N {
3212 struct S { friend void f<int>(int); }
3213 }
3215 we will have set the DECL_CONTEXT for the friend
3216 declaration to N, rather than to the global namespace. */
3221 /* This is not really a declaration of a specialization.
3222 It's just the name of an instantiation. But, it's not
3223 a request for an instantiation, either. */
3226 /* A specialization is not necessarily COMDAT. */
3232 /* If this is a full specialization, register it so that we can find
3233 it again. Partial specializations will be registered in
3234 process_partial_specialization. */
3236 {
3241 }
3244 /* A 'structor should already have clones. */
3250 }
3251 }
3254 }
3256 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3257 parameters. These are represented in the same format used for
3258 DECL_TEMPLATE_PARMS. */
3260 int
3262 {
3263 const_tree p1;
3264 const_tree p2;
3272 {
3284 {
3288 /* If either of the template parameters are invalid, assume
3289 they match for the sake of error recovery. */
3302 }
3303 }
3306 /* One set of parameters has more parameters lists than the
3307 other. */
3311 }
3313 /* Determine whether PARM is a parameter pack. */
3315 bool
3317 {
3318 /* Determine if we have a non-type template parameter pack. */
3325 /* If this is a list of template parameters, we could get a
3326 TYPE_DECL or a TEMPLATE_DECL. */
3330 /* Otherwise it must be a type template parameter. */
3334 }
3336 /* Determine if T is a function parameter pack. */
3338 bool
3340 {
3344 }
3346 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3347 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3349 tree
3351 {
3358 }
3360 /* Return true iff the function parameter PARAM_DECL was expanded
3361 from the function parameter pack PACK. */
3363 bool
3365 {
3370 /* The parameter pack and its pack arguments have the same
3371 DECL_PARM_INDEX. */
3373 }
3375 /* Determine whether ARGS describes a variadic template args list,
3376 i.e., one that is terminated by a template argument pack. */
3378 static bool
3380 {
3382 tree last_parm;
3396 }
3398 /* Generate a new name for the parameter pack name NAME (an
3399 IDENTIFIER_NODE) that incorporates its */
3401 static tree
3403 {
3404 /* Munge the name to include the parameter index. */
3405 #define NUMBUF_LEN 128
3419 }
3421 /* Return true if T is a primary function, class or alias template
3422 specialization, not including the template pattern. */
3424 bool
3426 {
3442 }
3444 /* Return true if PARM is a template template parameter. */
3446 bool
3448 {
3450 }
3452 /* Return true iff PARM is a DECL representing a type template
3453 parameter. */
3455 bool
3457 {
3462 }
3464 /* Return the template parameters of T if T is a
3465 primary template instantiation, NULL otherwise. */
3467 tree
3469 {
3474 parms = INNERMOST_TEMPLATE_PARMS
3478 }
3480 /* Return the template parameters of the LEVELth level from the full list
3481 of template parameters PARMS. */
3483 tree
3485 {
3486 tree p;
3497 }
3499 /* Returns the template arguments of T if T is a template instantiation,
3500 NULL otherwise. */
3502 tree
3504 {
3512 }
3514 /* Return the argument pack elements of T if T is a template argument pack,
3515 NULL otherwise. */
3517 tree
3519 {
3525 }
3527 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3528 ARGUMENT_PACK_SELECT represents. */
3530 static tree
3532 {
3536 /* If the selected argument is an expansion E, that most likely means we were
3537 called from gen_elem_of_pack_expansion_instantiation during the
3538 substituting of an argument pack (of which the Ith element is a pack
3539 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3540 In this case, the Ith element resulting from this substituting is going to
3541 be a pack expansion, which pattern is the pattern of E. Let's return the
3542 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3543 resulting pack expansion from it. */
3545 {
3546 /* Make sure we aren't throwing away arg info. */
3549 }
3552 }
3555 /* True iff FN is a function representing a built-in variadic parameter
3556 pack. */
3558 bool
3560 {
3570 }
3572 /* True iff CALL is a call to a function representing a built-in variadic
3573 parameter pack. */
3575 static bool
3577 {
3581 }
3583 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3585 static tree
3587 tree in_decl)
3588 {
3594 {
3596 {
3599 }
3604 }
3605 else
3606 {
3610 /* Calculate the largest value of len that won't make the size of the vec
3611 overflow an int. The compiler will exceed resource limits long before
3612 this, but it seems a decent place to diagnose. */
3616 {
3621 }
3629 }
3630 }
3632 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3633 CALL. */
3635 static tree
3637 tree in_decl)
3638 {
3648 }
3650 /* Structure used to track the progress of find_parameter_packs_r. */
3651 struct find_parameter_pack_data
3652 {
3653 /* TREE_LIST that will contain all of the parameter packs found by
3654 the traversal. */
3657 /* Set of AST nodes that have been visited by the traversal. */
3660 /* True iff we're making a type pack expansion. */
3662 };
3664 /* Identifies all of the argument packs that occur in a template
3665 argument and appends them to the TREE_LIST inside DATA, which is a
3666 find_parameter_pack_data structure. This is a subroutine of
3667 make_pack_expansion and uses_parameter_packs. */
3668 static tree
3670 {
3676 /* Handle type aliases/typedefs. */
3678 {
3685 }
3687 /* Identify whether this is a parameter pack or not. */
3689 {
3697 /* FALLTHRU */
3699 /* If the placeholder appears in the decl-specifier-seq of a function
3700 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3701 is a pack expansion, the invented template parameter is a template
3702 parameter pack. */
3712 {
3713 /* We don't want to walk into the type of a PARM_DECL,
3714 because we don't want to see the type parameter pack. */
3717 }
3722 {
3723 /* We don't want to walk into the type of a variadic capture proxy,
3724 because we don't want to see the type parameter pack. */
3727 }
3729 {
3731 find_parameter_packs_r,
3734 }
3746 /* Not a parameter pack. */
3748 }
3751 {
3752 /* Add this parameter pack to the list. */
3754 }
3760 /* This switch statement will return immediately if we don't find a
3761 parameter pack. */
3763 {
3768 /* Check the template itself. */
3771 /* Check the template arguments. */
3785 /* Ignore the declaration of a capture proxy for a parameter pack. */
3793 /* Fall through. */
3838 {
3839 /* Look at explicit captures. */
3844 /* Since we defer implicit capture, look in the parms and body. */
3852 }
3855 {
3856 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3857 type_pack_expansion_p to false so that any placeholders
3858 within the expression don't get marked as parameter packs. */
3866 }
3875 /* Don't walk into IF_STMT_EXTRA_ARGS. */
3881 }
3884 }
3886 /* Determines if the expression or type T uses any parameter packs. */
3887 bool
3889 {
3898 }
3900 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3901 representation a base-class initializer into a parameter pack
3902 expansion. If all goes well, the resulting node will be an
3903 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3904 respectively. */
3905 tree
3907 {
3908 tree result;
3917 {
3918 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3919 class initializer. In this case, the TREE_PURPOSE will be a
3920 _TYPE node (representing the base class expansion we're
3921 initializing) and the TREE_VALUE will be a TREE_LIST
3922 containing the initialization arguments.
3924 The resulting expansion looks somewhat different from most
3925 expansions. Rather than returning just one _EXPANSION, we
3926 return a TREE_LIST whose TREE_PURPOSE is a
3927 TYPE_PACK_EXPANSION containing the bases that will be
3928 initialized. The TREE_VALUE will be identical to the
3929 original TREE_VALUE, which is a list of arguments that will
3930 be passed to each base. We do not introduce any new pack
3931 expansion nodes into the TREE_VALUE (although it is possible
3932 that some already exist), because the TREE_PURPOSE and
3933 TREE_VALUE all need to be expanded together with the same
3934 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3935 resulting TREE_PURPOSE will mention the parameter packs in
3936 both the bases and the arguments to the bases. */
3937 tree purpose;
3938 tree value;
3941 /* Determine which parameter packs will be used by the base
3942 class expansion. */
3951 {
3954 arg);
3957 }
3960 {
3961 /* Collect the sets of parameter packs used in each of the
3962 initialization arguments. */
3964 {
3965 /* Determine which parameter packs will be expanded in this
3966 argument. */
3969 }
3970 }
3974 /* Create the pack expansion type for the base type. */
3980 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3981 they will rarely be compared to anything. */
3985 }
3990 /* Build the PACK_EXPANSION_* node. */
3991 result = for_types
3996 {
3997 /* Propagate type and const-expression information. */
4000 /* Mark this read now, since the expansion might be length 0. */
4002 }
4003 else
4004 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4005 they will rarely be compared to anything. */
4008 /* Determine which parameter packs will be expanded. */
4015 /* Make sure we found some parameter packs. */
4017 {
4019 {
4022 else
4024 }
4026 }
4032 }
4034 /* Checks T for any "bare" parameter packs, which have not yet been
4035 expanded, and issues an error if any are found. This operation can
4036 only be done on full expressions or types (e.g., an expression
4037 statement, "if" condition, etc.), because we could have expressions like:
4039 foo(f(g(h(args)))...)
4041 where "args" is a parameter pack. check_for_bare_parameter_packs
4042 should not be called for the subexpressions args, h(args),
4043 g(h(args)), or f(g(h(args))), because we would produce erroneous
4044 error messages.
4046 Returns TRUE and emits an error if there were bare parameter packs,
4047 returns FALSE otherwise. */
4048 bool
4050 {
4057 /* A lambda might use a parameter pack from the containing context. */
4072 {
4077 {
4088 else
4093 else
4097 }
4100 }
4103 }
4105 /* Expand any parameter packs that occur in the template arguments in
4106 ARGS. */
4107 tree
4109 {
4118 /* First, determine if we need to expand anything, and the number of
4119 slots we'll need. */
4121 {
4126 {
4130 else
4132 }
4133 else
4134 {
4136 num_result_args++;
4137 }
4138 }
4140 /* If no expansion is necessary, we're done. */
4144 /* Expand arguments. */
4147 non_default_args_count =
4150 {
4153 {
4160 }
4161 else
4162 {
4165 }
4166 }
4170 }
4172 /* Checks if DECL shadows a template parameter.
4174 [temp.local]: A template-parameter shall not be redeclared within its
4175 scope (including nested scopes).
4177 Emits an error and returns TRUE if the DECL shadows a parameter,
4178 returns FALSE otherwise. */
4180 bool
4182 {
4183 tree olddecl;
4185 /* If we're not in a template, we can't possibly shadow a template
4186 parameter. */
4190 /* Figure out what we're shadowing. */
4194 /* If there's no previous binding for this name, we're not shadowing
4195 anything, let alone a template parameter. */
4199 /* If we're not shadowing a template parameter, we're done. Note
4200 that OLDDECL might be an OVERLOAD (or perhaps even an
4201 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4202 node. */
4206 /* We check for decl != olddecl to avoid bogus errors for using a
4207 name inside a class. We check TPFI to avoid duplicate errors for
4208 inline member templates. */
4214 /* Don't complain about the injected class name, as we've already
4215 complained about the class itself. */
4222 else
4227 }
4229 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4230 ORIG_LEVEL, DECL, and TYPE. */
4232 static tree
4236 tree decl,
4237 tree type)
4238 {
4249 }
4251 /* Find the canonical type parameter for the given template type
4252 parameter. Returns the canonical type parameter, which may be TYPE
4253 if no such parameter existed. */
4255 static tree
4257 {
4258 tree list;
4272 else
4273 {
4277 }
4278 }
4280 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4281 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4282 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4283 new one is created. */
4285 static tree
4287 tsubst_flags_t complain)
4288 {
4293 {
4312 /* Template template parameters need this. */
4314 {
4321 }
4322 }
4325 }
4327 /* Process information from new template parameter PARM and append it
4328 to the LIST being built. This new parameter is a non-type
4329 parameter iff IS_NON_TYPE is true. This new parameter is a
4330 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4331 is in PARM_LOC. */
4333 tree
4336 {
4345 {
4349 {
4353 else
4355 }
4358 }
4361 {
4367 {
4368 /* [temp.param]
4370 The top-level cv-qualifiers on the template-parameter are
4371 ignored when determining its type. */
4376 && !is_parameter_pack
4377 /* If we're in a nested template parameter list, the template
4378 template parameter could be a parameter pack. */
4380 {
4381 /* This template parameter is not a parameter pack, but it
4382 should be. Complain about "bare" parameter packs. */
4385 /* Recover by calling this a parameter pack. */
4387 }
4388 }
4390 /* A template parameter is not modifiable. */
4399 processing_template_decl,
4404 }
4405 else
4406 {
4407 tree t;
4411 {
4413 /* This is for distinguishing between real templates and template
4414 template parameters */
4418 }
4419 else
4420 {
4422 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4425 }
4432 processing_template_decl,
4436 }
4440 /* Build requirements for the type/template parameter.
4441 This must be done after SET_DECL_TEMPLATE_PARM_P or
4442 process_template_parm could fail. */
4447 /* Build the parameter node linking the parameter declaration,
4448 its default argument (if any), and its constraints (if any). */
4453 }
4455 /* The end of a template parameter list has been reached. Process the
4456 tree list into a parameter vector, converting each parameter into a more
4457 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4458 as PARM_DECLs. */
4460 tree
4462 {
4467 /* Pop the dummy parameter level and add the real one. */
4470 current_template_parms
4475 {
4479 }
4484 }
4486 // Explicitly indicate the end of the template parameter list. We assume
4487 // that the current template parameters have been constructed and/or
4488 // managed explicitly, as when creating new template template parameters
4489 // from a shorthand constraint.
4490 void
4492 {
4494 }
4496 /* end_template_decl is called after a template declaration is seen. */
4498 void
4500 {
4506 /* This matches the pushlevel in begin_template_parm_list. */
4511 }
4513 /* Takes a TREE_LIST representing a template parameter and convert it
4514 into an argument suitable to be passed to the type substitution
4515 functions. Note that If the TREE_LIST contains an error_mark
4516 node, the returned argument is error_mark_node. */
4518 tree
4520 {
4533 {
4537 {
4538 /* Turn this argument into a TYPE_ARGUMENT_PACK
4539 with a single element, which expands T. */
4548 }
4549 }
4550 else
4551 {
4555 {
4556 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4557 with a single element, which expands T. */
4567 }
4568 else
4570 }
4572 }
4574 /* Given a single level of template parameters (a TREE_VEC), return it
4575 as a set of template arguments. */
4577 static tree
4579 {
4589 }
4591 /* Given a set of template parameters, return them as a set of template
4592 arguments. The template parameters are represented as a TREE_VEC, in
4593 the form documented in cp-tree.h for template arguments. */
4595 static tree
4597 {
4598 tree header;
4603 /* If there is only one level of template parameters, we do not
4604 create a TREE_VEC of TREE_VECs. Instead, we return a single
4605 TREE_VEC containing the arguments. */
4610 {
4615 else
4617 }
4620 }
4622 /* Within the declaration of a template, return the currently active
4623 template parameters as an argument TREE_VEC. */
4625 static tree
4627 {
4629 }
4631 /* Update the declared TYPE by doing any lookups which were thought to be
4632 dependent, but are not now that we know the SCOPE of the declarator. */
4634 tree
4636 {
4647 /* Don't bother building up the args in this case. */
4649 {
4650 /* tsubst in the args corresponding to the template parameters,
4651 including auto if present. Most things will be unchanged, but
4652 make_typename_type and tsubst_qualified_id will resolve
4653 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4656 tree pushed;
4658 {
4662 }
4667 }
4673 {
4676 else
4678 }
4680 }
4682 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4683 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4684 the new template is a member template. */
4686 static tree
4688 {
4697 }
4699 struct template_parm_data
4700 {
4701 /* The level of the template parameters we are currently
4702 processing. */
4705 /* The index of the specialization argument we are currently
4706 processing. */
4709 /* An array whose size is the number of template parameters. The
4710 elements are nonzero if the parameter has been used in any one
4711 of the arguments processed so far. */
4714 /* An array whose size is the number of template arguments. The
4715 elements are nonzero if the argument makes use of template
4716 parameters of this level. */
4718 };
4720 /* Subroutine of push_template_decl used to see if each template
4721 parameter in a partial specialization is used in the explicit
4722 argument list. If T is of the LEVEL given in DATA (which is
4723 treated as a template_parm_data*), then DATA->PARMS is marked
4724 appropriately. */
4726 static int
4728 {
4736 {
4739 }
4741 /* In C++17 the type of a non-type argument is a deduced context. */
4746 data,
4747 NULL,
4750 /* Return zero so that for_each_template_parm will continue the
4751 traversal of the tree; we want to mark *every* template parm. */
4753 }
4755 /* Process the partial specialization DECL. */
4757 static tree
4759 {
4766 tree inner_parms;
4767 tree inst;
4777 /* A concept cannot be specialized. */
4779 {
4782 }
4787 /* We check that each of the template parameters given in the
4788 partial specialization is used in the argument list to the
4789 specialization. For example:
4791 template <class T> struct S;
4792 template <class T> struct S<T*>;
4794 The second declaration is OK because `T*' uses the template
4795 parameter T, whereas
4797 template <class T> struct S<int>;
4799 is no good. Even trickier is:
4801 template <class T>
4802 struct S1
4803 {
4804 template <class U>
4805 struct S2;
4806 template <class U>
4807 struct S2<T>;
4808 };
4810 The S2<T> declaration is actually invalid; it is a
4811 full-specialization. Of course,
4813 template <class U>
4814 struct S2<T (*)(U)>;
4816 or some such would have been OK. */
4824 {
4829 NULL,
4831 }
4834 {
4835 /* One of the template parms was not used in a deduced context in the
4836 specialization. */
4838 {
4842 }
4846 }
4851 /* [temp.class.spec]
4853 The argument list of the specialization shall not be identical to
4854 the implicit argument list of the primary template. */
4855 tree main_args
4858 && (!flag_concepts
4861 {
4864 "any template arguments; to define the primary template, "
4866 else
4868 "template arguments and is not more constrained than "
4869 "the primary template; to define the primary template, "
4872 }
4874 /* A partial specialization that replaces multiple parameters of the
4875 primary template with a pack expansion is less specialized for those
4876 parameters. */
4878 {
4880 "primary template because it replaces multiple parameters "
4883 /* Avoid crash in process_partial_specialization. */
4885 }
4887 /* If we aren't in a dependent class, we can actually try deduction. */
4889 /* FIXME we should be able to handle a partial specialization of a
4890 partial instantiation, but currently we can't (c++/41727). */
4893 {
4897 maintmpl);
4898 }
4900 /* [temp.class.spec]
4902 A partially specialized non-type argument expression shall not
4903 involve template parameters of the partial specialization except
4904 when the argument expression is a simple identifier.
4906 The type of a template parameter corresponding to a specialized
4907 non-type argument shall not be dependent on a parameter of the
4908 specialization.
4910 Also, we verify that pack expansions only occur at the
4911 end of the argument list. */
4915 {
4922 {
4923 /* Extract the arguments from the argument pack. We'll be
4924 iterating over these in the following loop. */
4927 }
4930 {
4932 /* Get the Jth argument in the parameter pack. */
4936 {
4937 /* Pack expansions must come at the end of the
4938 argument list. */
4941 {
4945 else
4948 }
4949 }
4952 /* We only care about the pattern. */
4958 /* This next two lines are the `argument expression is not just a
4959 simple identifier' condition and also the `specialized
4960 non-type argument' bit. */
4964 {
4968 arg);
4969 else
4970 {
4971 /* Look at the corresponding template parameter,
4972 marking which template parameters its type depends
4973 upon. */
4977 {
4978 /* We haven't yet initialized TPD2. Do so now. */
4980 /* The number of parameters here is the number in the
4981 main template, which, as checked in the assertion
4982 above, is NARGS. */
4986 }
4988 /* Mark the template parameters. But this time, we're
4989 looking for the template parameters of the main
4990 template, not in the specialization. */
4997 NULL,
5001 {
5002 /* The type depended on some template parameters.
5003 If they are fully specialized in the
5004 specialization, that's OK. */
5013 "type %qT of template argument %qE depends "
5015 "type %qT of template argument %qE depends "
5017 type,
5018 arg);
5019 }
5020 }
5021 }
5022 }
5023 }
5025 /* We should only get here once. */
5029 // Build the template decl.
5038 /* Give template template parms a DECL_CONTEXT of the template
5039 for which they are a parameter. */
5041 {
5045 }
5048 /* We didn't register this in check_explicit_specialization so we could
5049 wait until the constraints were set. */
5051 else
5061 {
5067 {
5075 "declaration of %qD ambiguates earlier template "
5079 "partial specialization of %qD after instantiation "
5081 }
5082 }
5085 }
5087 /* PARM is a template parameter of some form; return the corresponding
5088 TEMPLATE_PARM_INDEX. */
5090 static tree
5092 {
5105 }
5107 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5108 parameter packs used by the template parameter PARM. */
5110 static void
5112 {
5113 /* A type parm can't refer to another parm. */
5117 {
5121 }
5128 }
5130 /* PARM is a template parameter pack. Return any parameter packs used in
5131 its type or the type of any of its template parameters. If there are
5132 any such packs, it will be instantiated into a fixed template parameter
5133 list by partial instantiation rather than be fully deduced. */
5135 tree
5137 {
5138 /* This can only be true in a member template. */
5141 /* This can only be true for a parameter pack. */
5144 /* A type parm can't refer to another parm. */
5158 }
5160 /* Check that a template declaration's use of default arguments and
5161 parameter packs is not invalid. Here, PARMS are the template
5162 parameters. IS_PRIMARY is true if DECL is the thing declared by
5163 a primary template. IS_PARTIAL is true if DECL is a partial
5164 specialization.
5166 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5167 function template declaration or a friend class template
5168 declaration. In the function case, 1 indicates a declaration, 2
5169 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5170 emitted for extraneous default arguments.
5172 Returns TRUE if there were no errors found, FALSE otherwise. */
5174 bool
5177 {
5180 tree parm_level;
5183 /* [temp.param]
5185 A default template-argument shall not be specified in a
5186 function template declaration or a function template definition, nor
5187 in the template-parameter-list of the definition of a member of a
5188 class template. */
5192 /* You can't have a function template declaration in a local
5193 scope, nor you can you define a member of a class template in a
5194 local scope. */
5202 /* A lambda doesn't have an explicit declaration; don't complain
5203 about the parms of the enclosing class. */
5210 /* If this is either a friend defined in the scope of the class
5211 or a member function. */
5217 /* And, if it was a member function, it really was defined in
5218 the scope of the class. */
5221 /* We already checked these parameters when the template was
5222 declared, so there's no need to do it again now. This function
5223 was defined in class scope, but we're processing its body now
5224 that the class is complete. */
5227 /* Core issue 226 (C++0x only): the following only applies to class
5228 templates. */
5231 {
5232 /* [temp.param]
5234 If a template-parameter has a default template-argument, all
5235 subsequent template-parameters shall have a default
5236 template-argument supplied. */
5238 {
5245 {
5255 {
5257 /* For better subsequent error-recovery, we indicate that
5258 there should have been a default argument. */
5261 }
5263 && !is_friend_decl
5264 /* Don't complain about an enclosing partial
5265 specialization. */
5270 /* A fixed parameter pack will be partially
5271 instantiated into a fixed length list. */
5273 {
5274 /* A primary class template can only have one
5275 parameter pack, at the end of the template
5276 parameter list. */
5284 }
5285 }
5286 }
5287 }
5290 || is_partial
5291 || !is_primary
5293 /* For an ordinary class template, default template arguments are
5294 allowed at the innermost level, e.g.:
5295 template <class T = int>
5296 struct S {};
5297 but, in a partial specialization, they're not allowed even
5298 there, as we have in [temp.class.spec]:
5300 The template parameter list of a specialization shall not
5301 contain default template argument values.
5303 So, for a partial specialization, or for a function template
5304 (in C++98/C++03), we look at all of them. */
5305 ;
5306 else
5307 /* But, for a primary class template that is not a partial
5308 specialization we look at all template parameters except the
5309 innermost ones. */
5312 /* Figure out what error message to issue. */
5327 else
5328 /* Per [temp.param]/9, "A default template-argument shall not be
5329 specified in the template-parameter-lists of the definition of
5330 a member of a class template that appears outside of the member's
5331 class.", thus if we aren't handling a member of a class template
5332 there is no need to examine the parameters. */
5336 /* If we're inside a class definition, there's no need to
5337 examine the parameters to the class itself. On the one
5338 hand, they will be checked when the class is defined, and,
5339 on the other, default arguments are valid in things like:
5340 template <class T = double>
5341 struct S { template <class U> void f(U); };
5342 Here the default argument for `S' has no bearing on the
5343 declaration of `f'. */
5345 else
5346 /* Check everything. */
5352 {
5359 {
5364 {
5366 {
5373 }
5375 /* Clear out the default argument so that we are not
5376 confused later. */
5378 }
5379 }
5381 /* At this point, if we're still interested in issuing messages,
5382 they must apply to classes surrounding the object declared. */
5386 }
5389 }
5391 /* Worker for push_template_decl_real, called via
5392 for_each_template_parm. DATA is really an int, indicating the
5393 level of the parameters we are interested in. If T is a template
5394 parameter of that level, return nonzero. */
5396 static int
5398 {
5404 else
5407 }
5409 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5410 DATA is really an int, indicating the innermost outer level of parameters.
5411 If T is a template parameter of that level or further out, return
5412 nonzero. */
5414 static int
5416 {
5422 else
5425 }
5427 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5428 parameters given by current_template_args, or reuses a
5429 previously existing one, if appropriate. Returns the DECL, or an
5430 equivalent one, if it is replaced via a call to duplicate_decls.
5432 If IS_FRIEND is true, DECL is a friend declaration. */
5434 tree
5436 {
5437 tree tmpl;
5438 tree args;
5439 tree info;
5440 tree ctx;
5444 /* True if the template is a member template, in the sense of
5445 [temp.mem]. */
5451 /* See if this is a partial specialization. */
5464 /* For a friend, we want the context of the friend, not
5465 the type of which it is a friend. */
5469 /* In the case of a virtual function, we want the class in which
5470 it is defined. */
5472 else
5473 /* Otherwise, if we're currently defining some class, the DECL
5474 is assumed to be a member of the class. */
5483 /* See if this is a primary template. */
5486 /* A friend template that specifies a class context, i.e.
5487 template <typename T> friend void A<T>::f();
5488 is not primary. */
5493 else
5497 {
5504 {
5507 }
5509 {
5511 {
5514 }
5516 {
5517 /* [temp.mem]
5519 A destructor shall not be a member template. */
5522 }
5529 {
5530 /* [basic.stc.dynamic.allocation]
5532 An allocation function can be a function
5533 template. ... Template allocation functions shall
5534 have two or more parameters. */
5537 }
5538 }
5541 {
5542 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5545 {
5551 }
5552 }
5555 /* alias-declaration */
5559 else
5560 {
5563 }
5564 }
5566 /* Check to see that the rules regarding the use of default
5567 arguments are not being violated. We check args for a friend
5568 functions when we know whether it's a definition, introducing
5569 declaration or re-declaration. */
5574 /* Ensure that there are no parameter packs in the type of this
5575 declaration that have not been expanded. */
5577 {
5578 /* Check each of the arguments individually to see if there are
5579 any bare parameter packs. */
5585 {
5588 {
5589 /* This is a PARM_DECL that contains unexpanded parameter
5590 packs. We have already complained about this in the
5591 check_for_bare_parameter_packs call, so just replace
5592 these types with ERROR_MARK_NODE. */
5595 }
5599 }
5601 /* Check for bare parameter packs in the return type and the
5602 exception specifiers. */
5604 /* Errors were already issued, set return type to int
5605 as the frontend doesn't expect error_mark_node as
5606 the return type. */
5610 }
5615 {
5618 }
5631 {
5636 /* If DECL is a TYPE_DECL for a class-template, then there won't
5637 be DECL_LANG_SPECIFIC. The information equivalent to
5638 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5642 {
5643 /* Since a template declaration already existed for this
5644 class-type, we must be redeclaring it here. Make sure
5645 that the redeclaration is valid. */
5647 current_template_parms,
5649 /* We don't need to create a new TEMPLATE_DECL; just use the
5650 one we already had. */
5652 }
5653 else
5654 {
5656 member_template_p);
5661 {
5662 /* A specialization of a member template of a template
5663 class. */
5667 }
5668 }
5669 }
5670 else
5671 {
5677 {
5680 }
5688 {
5689 tree new_tmpl;
5691 /* The declaration is a specialization of a member
5692 template, declared outside the class. Therefore, the
5693 innermost template arguments will be NULL, so we
5694 replace them with the arguments determined by the
5695 earlier call to check_explicit_specialization. */
5698 new_tmpl
5700 member_template_p);
5710 args,
5713 }
5715 /* Make sure the template headers we got make sense. */
5720 {
5725 }
5726 else
5728 {
5733 {
5737 else
5741 /* Avoid crash in import_export_decl. */
5744 }
5749 /* Can happen in erroneous input. */
5751 else
5753 }
5755 /* Check that the parms are used in the appropriate qualifying scopes
5756 in the declarator. */
5760 {
5766 /* Avoid crash in import_export_decl. */
5769 }
5770 }
5775 /* Push template declarations for global functions and types. Note
5776 that we do not try to push a global template friend declared in a
5777 template class; such a thing may well depend on the template
5778 parameters of the class. */
5781 {
5786 /* Hide template friend classes that haven't been declared yet. */
5788 {
5791 }
5792 }
5795 {
5800 /* Give template template parms a DECL_CONTEXT of the template
5801 for which they are a parameter. */
5804 {
5808 }
5814 }
5816 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5817 back to its most general template. If TMPL is a specialization,
5818 ARGS may only have the innermost set of arguments. Add the missing
5819 argument levels if necessary. */
5827 else
5828 {
5833 }
5836 && !is_friend
5839 /* Set DECL_COMDAT on template instantiations; if we force
5840 them to be emitted by explicit instantiation or -frepo,
5841 mark_needed will tell cgraph to do the right thing. */
5845 }
5847 tree
5849 {
5851 }
5853 /* FN is an inheriting constructor that inherits from the constructor
5854 template INHERITED; turn FN into a constructor template with a matching
5855 template header. */
5857 tree
5859 {
5860 tree inner_parms
5863 tree parms
5874 }
5876 /* Called when a class template TYPE is redeclared with the indicated
5877 template PARMS, e.g.:
5879 template <class T> struct S;
5880 template <class T> struct S {}; */
5882 bool
5884 {
5885 tree tmpl;
5886 tree tmpl_parms;
5890 {
5893 }
5897 /* The type is nested in some template class. Nothing to worry
5898 about here; there are no new template parameters for the nested
5899 type. */
5903 {
5905 tmpl);
5907 }
5913 {
5923 }
5926 {
5927 tree tmpl_parm;
5928 tree parm;
5929 tree tmpl_default;
5930 tree parm_default;
5944 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5945 TEMPLATE_DECL. */
5955 {
5959 }
5962 {
5963 /* We have in [temp.param]:
5965 A template-parameter may not be given default arguments
5966 by two different declarations in the same scope. */
5971 }
5974 /* Update the previous template parameters (which are the ones
5975 that will really count) with the new default value. */
5978 /* Update the new parameters, too; they'll be used as the
5979 parameters for any members. */
5982 /* Give each template template parm in this redeclaration a
5983 DECL_CONTEXT of the template for which they are a parameter. */
5985 {
5988 }
5992 }
5994 // Cannot redeclare a class template with a different set of constraints.
5996 {
6001 }
6004 }
6006 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
6007 to be used when the caller has already checked
6008 (processing_template_decl
6009 && !instantiation_dependent_expression_p (expr)
6010 && potential_constant_expression (expr))
6011 and cleared processing_template_decl. */
6013 tree
6015 {
6018 complain,
6022 }
6024 /* Simplify EXPR if it is a non-dependent expression. Returns the
6025 (possibly simplified) expression. */
6027 tree
6029 {
6033 /* If we're in a template, but EXPR isn't value dependent, simplify
6034 it. We're supposed to treat:
6036 template <typename T> void f(T[1 + 1]);
6037 template <typename T> void f(T[2]);
6039 as two declarations of the same function, for example. */
6042 {
6043 processing_template_decl_sentinel s;
6045 }
6047 }
6049 tree
6051 {
6053 }
6055 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
6056 an uninstantiated expression. */
6058 tree
6060 {
6064 {
6067 else
6068 {
6069 processing_template_decl_sentinel s;
6071 }
6072 }
6074 }
6076 /* True iff T is a specialization of a variable template. */
6078 bool
6080 {
6085 }
6087 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6088 template declaration, or a TYPE_DECL for an alias declaration. */
6090 bool
6092 {
6100 }
6102 /* Return TRUE iff T is a specialization of an alias template. */
6104 bool
6106 {
6107 /* It's an alias template specialization if it's an alias and its
6108 TYPE_NAME is a specialization of a primary template. */
6114 }
6116 /* An alias template is complex from a SFINAE perspective if a template-id
6117 using that alias can be ill-formed when the expansion is not, as with
6118 the void_t template. We determine this by checking whether the
6119 expansion for the alias template uses all its template parameters. */
6121 struct uses_all_template_parms_data
6122 {
6125 };
6127 static int
6129 {
6137 }
6139 static bool
6141 {
6156 }
6158 /* Return TRUE iff T is a specialization of a complex alias template with
6159 dependent template-arguments. */
6161 bool
6163 {
6176 }
6178 /* Return the number of innermost template parameters in TMPL. */
6180 static int
6182 {
6185 }
6187 /* Return either TMPL or another template that it is equivalent to under DR
6188 1286: An alias that just changes the name of a template is equivalent to
6189 the other template. */
6191 static tree
6193 {
6196 {
6197 /* Determine if the alias is equivalent to an underlying template. */
6209 tree alias_args = INNERMOST_TEMPLATE_ARGS
6214 /* Alias is equivalent. Strip it and repeat. */
6216 }
6219 }
6221 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6222 must be a reference-to-function or a pointer-to-function type, as specified
6223 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6224 and check that the resulting function has external linkage. */
6226 static tree
6228 tsubst_flags_t complain)
6229 {
6232 linkage_kind linkage;
6247 /* [temp.arg.nontype]/1
6249 A template-argument for a non-type, non-template template-parameter
6250 shall be one of:
6251 [...]
6252 -- the address of an object or function with external [C++11: or
6253 internal] linkage. */
6256 {
6258 {
6264 else
6267 }
6269 }
6273 {
6275 {
6280 else
6284 }
6286 }
6288 accept:
6290 {
6293 else
6295 }
6300 }
6302 /* Subroutine of convert_nontype_argument.
6303 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6304 Emit an error otherwise. */
6306 static bool
6308 tsubst_flags_t complain)
6309 {
6326 {
6331 else
6333 }
6335 }
6337 /* Returns TRUE iff the address of OP is value-dependent.
6339 14.6.2.4 [temp.dep.temp]:
6340 A non-integral non-type template-argument is dependent if its type is
6341 dependent or it has either of the following forms
6342 qualified-id
6343 & qualified-id
6344 and contains a nested-name-specifier which specifies a class-name that
6345 names a dependent type.
6347 We generalize this to just say that the address of a member of a
6348 dependent class is value-dependent; the above doesn't cover the
6349 address of a static data member named with an unqualified-id. */
6351 static bool
6353 {
6354 /* We could use get_inner_reference here, but there's no need;
6355 this is only relevant for template non-type arguments, which
6356 can only be expressed as &id-expression. */
6358 {
6362 }
6365 }
6367 /* The next set of functions are used for providing helpful explanatory
6368 diagnostics for failed overload resolution. Their messages should be
6369 indented by two spaces for consistency with the messages in
6370 call.c */
6372 static int
6374 {
6376 }
6378 /* Other failure functions should call this one, to provide a single function
6379 for setting a breakpoint on. */
6381 static int
6383 {
6385 }
6387 static int
6389 {
6394 }
6396 static int
6398 {
6404 }
6406 static int
6408 {
6412 }
6414 static int
6416 {
6419 " template parameter %qD is not a parameter pack, but "
6423 }
6425 static int
6427 {
6430 " template argument %qE does not match "
6434 }
6436 static int
6438 {
6442 }
6444 static int
6446 {
6452 }
6454 static int
6456 {
6458 {
6463 else
6465 " deduced conflicting values for non-type parameter "
6467 }
6469 }
6471 static int
6473 {
6476 " variable-sized array type %qT is not "
6478 arg);
6480 }
6482 static int
6484 {
6488 arg);
6490 }
6492 static int
6494 {
6496 {
6502 else
6507 }
6509 }
6511 static int
6513 {
6515 }
6517 static int
6520 {
6522 }
6524 static int
6527 {
6533 }
6535 static int
6538 {
6541 {
6549 }
6551 }
6553 static int
6555 {
6558 " template parameters of a template template argument are "
6561 }
6563 static int
6565 {
6571 }
6573 static int
6575 {
6580 }
6582 /* Attempt to convert the non-type template parameter EXPR to the
6583 indicated TYPE. If the conversion is successful, return the
6584 converted value. If the conversion is unsuccessful, return
6585 NULL_TREE if we issued an error message, or error_mark_node if we
6586 did not. We issue error messages for out-and-out bad template
6587 parameters, but not simply because the conversion failed, since we
6588 might be just trying to do argument deduction. Both TYPE and EXPR
6589 must be non-dependent.
6591 The conversion follows the special rules described in
6592 [temp.arg.nontype], and it is much more strict than an implicit
6593 conversion.
6595 This function is called twice for each template argument (see
6596 lookup_template_class for a more accurate description of this
6597 problem). This means that we need to handle expressions which
6598 are not valid in a C++ source, but can be created from the
6599 first call (for instance, casts to perform conversions). These
6600 hacks can go away after we fix the double coercion problem. */
6602 static tree
6604 {
6605 tree expr_type;
6609 /* Detect immediately string literals as invalid non-type argument.
6610 This special-case is not needed for correctness (we would easily
6611 catch this later), but only to provide better diagnostic for this
6612 common user mistake. As suggested by DR 100, we do not mention
6613 linkage issues in the diagnostic as this is not the point. */
6614 /* FIXME we're making this OK. */
6616 {
6622 }
6624 /* Add the ADDR_EXPR now for the benefit of
6625 value_dependent_expression_p. */
6628 {
6632 }
6634 /* If we are in a template, EXPR may be non-dependent, but still
6635 have a syntactic, rather than semantic, form. For example, EXPR
6636 might be a SCOPE_REF, rather than the VAR_DECL to which the
6637 SCOPE_REF refers. Preserving the qualifying scope is necessary
6638 so that access checking can be performed when the template is
6639 instantiated -- but here we need the resolved form so that we can
6640 convert the argument. */
6652 /* If the argument is non-dependent, perform any conversions in
6653 non-dependent context as well. */
6661 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6662 to a non-type argument of "nullptr". */
6666 /* In C++11, integral or enumeration non-type template arguments can be
6667 arbitrary constant expressions. Pointer and pointer to
6668 member arguments can be general constant expressions that evaluate
6669 to a null value, but otherwise still need to be of a specific form. */
6671 {
6673 /* A PTRMEM_CST is already constant, and a valid template
6674 argument for a parameter of pointer to member type, we just want
6675 to leave it in that form rather than lower it to a
6679 {
6680 /* C++17: A template-argument for a non-type template-parameter shall
6681 be a converted constant expression (8.20) of the type of the
6682 template-parameter. */
6688 }
6690 {
6695 }
6696 }
6700 else
6703 /* HACK: Due to double coercion, we can get a
6704 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6705 which is the tree that we built on the first call (see
6706 below when coercing to reference to object or to reference to
6707 function). We just strip everything and get to the arg.
6708 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6709 for examples. */
6711 {
6717 {
6718 /* ??? Maybe we could use convert_from_reference here, but we
6719 would need to relax its constraints because the NOP_EXPR
6720 could actually change the type to something more cv-qualified,
6721 and this is not folded by convert_from_reference. */
6726 && (same_type_ignoring_top_level_qualifiers_p
6729 {
6732 }
6733 }
6734 }
6736 /* [temp.arg.nontype]/5, bullet 1
6738 For a non-type template-parameter of integral or enumeration type,
6739 integral promotions (_conv.prom_) and integral conversions
6740 (_conv.integral_) are applied. */
6742 {
6744 {
6749 }
6754 /* Notice that there are constant expressions like '4 % 0' which
6755 do not fold into integer constants. */
6758 {
6760 {
6764 else
6770 /* else cxx_constant_value complained but gave us
6771 a real constant, so go ahead. */
6773 {
6774 /* Some assemble time constant expressions like
6775 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6776 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6777 as we can emit them into .rodata initializers of
6778 variables, yet they can't fold into an INTEGER_CST at
6779 compile time. Refuse them here. */
6784 }
6785 }
6786 else
6788 }
6790 /* Avoid typedef problems. */
6793 }
6794 /* [temp.arg.nontype]/5, bullet 2
6796 For a non-type template-parameter of type pointer to object,
6797 qualification conversions (_conv.qual_) and the array-to-pointer
6798 conversion (_conv.array_) are applied. */
6800 {
6803 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6804 decay_conversion or an explicit cast. If it's a problematic cast,
6805 we'll complain about it below. */
6807 {
6812 {
6815 }
6816 }
6818 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6820 A template-argument for a non-type, non-template template-parameter
6821 shall be one of: [...]
6823 -- the name of a non-type template-parameter;
6824 -- the address of an object or function with external linkage, [...]
6825 expressed as "& id-expression" where the & is optional if the name
6826 refers to a function or array, or if the corresponding
6827 template-parameter is a reference.
6829 Here, we do not care about functions, as they are invalid anyway
6830 for a parameter of type pointer-to-object. */
6833 /* Non-type template parameters are OK. */
6834 ;
6838 {
6840 {
6843 "because %qD is a variable, not the address of "
6846 }
6848 {
6854 }
6855 /* Other values, like integer constants, might be valid
6856 non-type arguments of some other type. */
6858 }
6859 else
6860 {
6864 {
6869 }
6871 {
6877 }
6880 {
6885 }
6886 /* C++17: For a non-type template-parameter of reference or pointer
6887 type, the value of the constant expression shall not refer to (or
6888 for a pointer type, shall not be the address of):
6889 * a subobject (4.5),
6890 * a temporary object (15.2),
6891 * a string literal (5.13.5),
6892 * the result of a typeid expression (8.2.8), or
6893 * a predefined __func__ variable (11.4.1). */
6895 {
6898 decl);
6900 }
6904 {
6909 }
6911 {
6915 decl);
6917 }
6918 }
6925 }
6926 /* [temp.arg.nontype]/5, bullet 3
6928 For a non-type template-parameter of type reference to object, no
6929 conversions apply. The type referred to by the reference may be more
6930 cv-qualified than the (otherwise identical) type of the
6931 template-argument. The template-parameter is bound directly to the
6932 template-argument, which must be an lvalue. */
6934 {
6936 expr_type))
6940 {
6945 }
6948 {
6953 }
6955 /* [temp.arg.nontype]/1
6957 A template-argument for a non-type, non-template template-parameter
6958 shall be one of: [...]
6960 -- the address of an object or function with external linkage. */
6963 {
6966 {
6969 "because a reference variable does not have a constant "
6972 }
6973 }
6977 /* OK, dependent reference. We don't want to ask whether a DECL is
6979 else
6980 {
6982 {
6988 }
6990 /* DR 1155 allows internal linkage in C++11 and up. */
6993 {
6999 }
7002 }
7006 }
7007 /* [temp.arg.nontype]/5, bullet 4
7009 For a non-type template-parameter of type pointer to function, only
7010 the function-to-pointer conversion (_conv.func_) is applied. If the
7011 template-argument represents a set of overloaded functions (or a
7012 pointer to such), the matching function is selected from the set
7013 (_over.over_). */
7015 {
7016 /* If the argument is a template-id, we might not have enough
7017 context information to decay the pointer. */
7019 {
7023 }
7026 /* Null pointer values are OK in C++11. */
7032 }
7033 /* [temp.arg.nontype]/5, bullet 5
7035 For a non-type template-parameter of type reference to function, no
7036 conversions apply. If the template-argument represents a set of
7037 overloaded functions, the matching function is selected from the set
7038 (_over.over_). */
7040 {
7042 {
7044 {
7049 }
7051 }
7056 }
7057 /* [temp.arg.nontype]/5, bullet 6
7059 For a non-type template-parameter of type pointer to member function,
7060 no conversions apply. If the template-argument represents a set of
7061 overloaded member functions, the matching member function is selected
7062 from the set (_over.over_). */
7064 {
7069 /* [temp.arg.nontype] bullet 1 says the pointer to member
7070 expression must be a pointer-to-member constant. */
7075 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7076 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7079 }
7080 /* [temp.arg.nontype]/5, bullet 7
7082 For a non-type template-parameter of type pointer to data member,
7083 qualification conversions (_conv.qual_) are applied. */
7085 {
7086 /* [temp.arg.nontype] bullet 1 says the pointer to member
7087 expression must be a pointer-to-member constant. */
7095 }
7097 {
7099 {
7104 }
7106 }
7107 /* A template non-type parameter must be one of the above. */
7108 else
7111 /* Sanity check: did we actually convert the argument to the
7112 right type? */
7116 }
7118 /* Subroutine of coerce_template_template_parms, which returns 1 if
7119 PARM_PARM and ARG_PARM match using the rule for the template
7120 parameters of template template parameters. Both PARM and ARG are
7121 template parameters; the rest of the arguments are the same as for
7122 coerce_template_template_parms.
7123 */
7124 static int
7126 tree arg,
7127 tsubst_flags_t complain,
7128 tree in_decl,
7129 tree outer_args)
7130 {
7139 {
7141 /* We encounter instantiations of templates like
7142 template <template <template <class> class> class TT>
7143 class C; */
7144 {
7151 }
7152 /* Fall through. */
7157 /* Argument is a parameter pack but parameter is not. */
7162 /* The tsubst call is used to handle cases such as
7164 template <int> class C {};
7165 template <class T, template <T> class TT> class D {};
7166 D<int, C> d;
7168 i.e. the parameter list of TT depends on earlier parameters. */
7170 {
7175 }
7179 /* Argument is a parameter pack but parameter is not. */
7186 }
7189 }
7191 /* Coerce template argument list ARGLIST for use with template
7192 template-parameter TEMPL. */
7194 static tree
7196 tsubst_flags_t complain)
7197 {
7198 /* Consider an example where a template template parameter declared as
7200 template <class T, class U = std::allocator<T> > class TT
7202 The template parameter level of T and U are one level larger than
7203 of TT. To proper process the default argument of U, say when an
7204 instantiation `TT<int>' is seen, we need to build the full
7205 arguments containing {int} as the innermost level. Outer levels,
7206 available when not appearing as default template argument, can be
7207 obtained from the arguments of the enclosing template.
7209 Suppose that TT is later substituted with std::vector. The above
7210 instantiation is `TT<int, std::allocator<T> >' with TT at
7211 level 1, and T at level 2, while the template arguments at level 1
7212 becomes {std::vector} and the inner level 2 is {int}. */
7216 {
7218 /* We want arguments for the partial specialization, not arguments for
7219 the primary template. */
7221 else
7223 }
7225 {
7226 /* This is an argument of the current template, so we haven't set
7227 DECL_CONTEXT yet. */
7228 tree relevant_template_parms;
7230 /* Parameter levels that are greater than the level of the given
7231 template template parm are irrelevant. */
7238 }
7245 complain,
7248 }
7250 /* A cache of template template parameters with match-all default
7251 arguments. */
7253 static void
7255 {
7259 }
7260 static tree
7262 {
7267 }
7269 /* T is a bound template template-parameter. Copy its arguments into default
7270 arguments of the template template-parameter's template parameters. */
7272 static tree
7274 {
7297 {
7300 {
7303 }
7304 }
7308 }
7310 /* ARG is a bound potential template template-argument, and PARGS is a list
7311 of arguments for the corresponding template template-parameter. Adjust
7312 PARGS as appropriate for application to ARG's template, and if ARG is a
7313 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7314 arguments to the template template parameter. */
7316 static tree
7318 {
7322 {
7323 /* When comparing two template template-parameters in partial ordering,
7324 rewrite the one currently being used as an argument to have default
7325 arguments for all parameters. */
7331 }
7332 else
7333 {
7334 tree aparms
7339 }
7342 }
7344 /* Subroutine of unify for the case when PARM is a
7345 BOUND_TEMPLATE_TEMPLATE_PARM. */
7347 static int
7350 {
7354 /* The template template parm might be variadic and the argument
7355 not, so flatten both argument lists. */
7360 {
7361 /* In keeping with P0522R0, adjust P's template arguments
7362 to apply to A's template; then flatten it again. */
7371 /* If the P0522 adjustment eliminated a pack expansion, deduce
7372 empty packs. */
7378 }
7379 else
7380 {
7381 /* Deduce arguments T, i from TT<T> or TT<i>.
7382 We check each element of PARMVEC and ARGVEC individually
7383 rather than the whole TREE_VEC since they can have
7384 different number of elements, which is allowed under N2555. */
7388 /* Check if the parameters end in a pack, making them
7389 variadic. */
7396 /* If the template argument list of P contains a pack
7397 expansion that is not the last template argument, the
7398 entire template argument list is a non-deduced
7399 context. */
7417 DEDUCE_EXACT,
7420 }
7423 }
7425 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7426 template template parameters. Both PARM_PARMS and ARG_PARMS are
7427 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7428 or PARM_DECL.
7430 Consider the example:
7431 template <class T> class A;
7432 template<template <class U> class TT> class B;
7434 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7435 the parameters to A, and OUTER_ARGS contains A. */
7437 static int
7439 tree arg_parms,
7440 tsubst_flags_t complain,
7441 tree in_decl,
7442 tree outer_args)
7443 {
7455 {
7456 /* P0522R0: A template template-parameter P is at least as specialized as
7457 a template template-argument A if, given the following rewrite to two
7458 function templates, the function template corresponding to P is at
7459 least as specialized as the function template corresponding to A
7460 according to the partial ordering rules for function templates
7461 ([temp.func.order]). Given an invented class template X with the
7462 template parameter list of A (including default arguments):
7464 * Each of the two function templates has the same template parameters,
7465 respectively, as P or A.
7467 * Each function template has a single function parameter whose type is
7468 a specialization of X with template arguments corresponding to the
7469 template parameters from the respective function template where, for
7470 each template parameter PP in the template parameter list of the
7471 function template, a corresponding template argument AA is formed. If
7472 PP declares a parameter pack, then AA is the pack expansion
7473 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7475 If the rewrite produces an invalid type, then P is not at least as
7476 specialized as A. */
7478 /* So coerce P's args to apply to A's parms, and then deduce between A's
7479 args and the converted args. If that succeeds, A is at least as
7480 specialized as P, so they match.*/
7487 {
7493 }
7494 }
7496 /* Determine whether we have a parameter pack at the end of the
7497 template template parameter's template parameter list. */
7499 {
7506 {
7520 }
7521 }
7527 /* Check all of the template parameters except the parameter pack at
7528 the end (if any). */
7530 {
7539 outer_args))
7542 }
7545 {
7546 /* Check each of the template parameters in the template
7547 argument against the template parameter pack at the end of
7548 the template template parameter. */
7555 {
7562 outer_args))
7564 }
7565 }
7568 }
7570 /* Verifies that the deduced template arguments (in TARGS) for the
7571 template template parameters (in TPARMS) represent valid bindings,
7572 by comparing the template parameter list of each template argument
7573 to the template parameter list of its corresponding template
7574 template parameter, in accordance with DR150. This
7575 routine can only be called after all template arguments have been
7576 deduced. It will return TRUE if all of the template template
7577 parameter bindings are okay, FALSE otherwise. */
7578 bool
7580 {
7584 /* We're dealing with template parms in this process. */
7590 {
7595 {
7600 {
7601 /* Look inside the argument pack. */
7604 }
7607 {
7611 /* Extract the next argument from the argument
7612 pack. */
7616 /* Look at the pattern of the pack expansion. */
7619 /* Extract the template parameters from the template
7620 argument. */
7626 /* Verify that we can coerce the template template
7627 parameters from the template argument to the template
7628 parameter. This requires an exact match. */
7630 && !coerce_template_template_parms
7632 targ_parms,
7633 tf_none,
7634 tparm,
7635 targs))
7636 {
7639 }
7640 }
7641 }
7642 }
7644 out:
7648 }
7650 /* Since type attributes aren't mangled, we need to strip them from
7651 template type arguments. */
7653 static tree
7655 {
7665 }
7667 /* And from inside dependent non-type arguments like sizeof(Type). */
7669 static tree
7671 {
7681 }
7683 // A template declaration can be substituted for a constrained
7684 // template template parameter only when the argument is more
7685 // constrained than the parameter.
7686 static bool
7688 {
7691 /* For now, allow constrained template template arguments
7692 and unconstrained template template parameters. */
7698 // If the template parameter is constrained, we need to rewrite its
7699 // constraints in terms of the ARG's template parameters. This ensures
7700 // that all of the template parameter types will have the same depth.
7701 //
7702 // Note that this is only valid when coerce_template_template_parm is
7703 // true for the innermost template parameters of PARM and ARG. In other
7704 // words, because coercion is successful, this conversion will be valid.
7706 {
7713 }
7716 }
7718 // Convert a placeholder argument into a binding to the original
7719 // parameter. The original parameter is saved as the TREE_TYPE of
7720 // ARG.
7723 {
7726 }
7728 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7729 because one of them is dependent. But we need to represent the
7730 conversion for the benefit of cp_tree_equal. */
7732 static tree
7734 {
7735 /* Auto parms get no conversion. */
7738 /* We don't need or want to add this conversion now if we're going to use the
7739 argument for deduction. */
7751 }
7753 /* Convert the indicated template ARG as necessary to match the
7754 indicated template PARM. Returns the converted ARG, or
7755 error_mark_node if the conversion was unsuccessful. Error and
7756 warning messages are issued under control of COMPLAIN. This
7757 conversion is for the Ith parameter in the parameter list. ARGS is
7758 the full set of template arguments deduced so far. */
7760 static tree
7762 tree arg,
7763 tree args,
7764 tsubst_flags_t complain,
7766 tree in_decl)
7767 {
7768 tree orig_arg;
7769 tree val;
7775 /* Trivially convert placeholders. */
7784 {
7785 /* The template argument was the name of some
7786 member function. That's usually
7787 invalid, but static members are OK. In any
7788 case, grab the underlying fields/functions
7789 and issue an error later if required. */
7792 }
7800 /* When determining whether an argument pack expansion is a template,
7801 look at the pattern. */
7805 /* Deal with an injected-class-name used as a template template arg. */
7807 {
7810 {
7820 }
7821 }
7823 is_tmpl_type =
7839 {
7841 {
7845 }
7848 "to refer to a type member of a template parameter, "
7853 typename_type,
7854 complain);
7857 }
7859 {
7861 {
7863 {
7875 else
7878 }
7879 }
7881 }
7883 {
7885 {
7892 else
7895 }
7897 }
7900 /* We already did the appropriate conversion when packing args. */
7903 {
7905 {
7907 /* The number of argument required is not known yet.
7908 Just accept it for now. */
7910 else
7911 {
7913 tree argparm;
7915 /* Strip alias templates that are equivalent to another
7916 template. */
7922 args))
7923 {
7926 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7927 TEMPLATE_DECL. */
7929 {
7934 }
7935 }
7936 else
7937 {
7939 {
7946 }
7949 }
7951 // Check that the constraints are compatible before allowing the
7952 // substitution.
7955 {
7957 {
7963 }
7965 }
7966 }
7967 }
7968 else
7970 /* We only form one instance of each template specialization.
7971 Therefore, if we use a non-canonical variant (i.e., a
7972 typedef), any future messages referring to the type will use
7973 the typedef, which is confusing if those future uses do not
7974 themselves also use the typedef. */
7977 }
7978 else
7979 {
7984 /* We don't have enough levels of args to do any substitution. This
7987 {
7991 }
7992 else
8000 /* We used to call digest_init here. However, digest_init
8001 will report errors, which we don't want when complain
8002 is zero. More importantly, digest_init will try too
8003 hard to convert things: for example, `0' should not be
8004 converted to pointer type at this point according to
8005 the standard. Accepting this is not merely an
8006 extension, since deciding whether or not these
8007 conversions can occur is part of determining which
8008 function template to call, or whether a given explicit
8009 argument specification is valid. */
8011 else
8012 {
8015 }
8025 {
8026 /* Reject template arguments that are references to built-in
8027 functions with no library fallbacks. */
8036 }
8039 {
8040 /* Strip typedefs from the SCOPE_REF. */
8043 complain);
8046 }
8047 }
8050 }
8052 /* Coerces the remaining template arguments in INNER_ARGS (from
8053 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8054 Returns the coerced argument pack. PARM_IDX is the position of this
8055 parameter in the template parameter list. ARGS is the original
8056 template argument list. */
8057 static tree
8060 tree args,
8061 tree inner_args,
8063 tree new_args,
8065 tree in_decl,
8066 tsubst_flags_t complain)
8067 {
8070 tree packed_args;
8071 tree argument_pack;
8078 {
8079 /* When the template parameter is a non-type template parameter pack
8080 or template template parameter pack whose type or template
8081 parameters use parameter packs, we know exactly how many arguments
8082 we are looking for. Build a vector of the instantiated decls for
8083 these template parameters in PACKED_PARMS. */
8084 /* We can't use make_pack_expansion here because it would interpret a
8085 _DECL as a use rather than a declaration. */
8099 /* If we're doing a partial instantiation of a member template,
8100 verify that all of the types used for the non-type
8101 template parameter pack are, in fact, valid for non-type
8102 template parameters. */
8105 {
8108 {
8112 }
8113 /* We don't know how many args we have yet, just
8114 use the unconverted ones for now. */
8116 }
8119 }
8120 /* Check if we have a placeholder pack, which indicates we're
8121 in the context of a introduction list. In that case we want
8122 to match this pack to the single placeholder. */
8126 {
8129 }
8130 else
8133 /* Convert the remaining arguments, which will be a part of the
8134 parameter pack "parm". */
8137 {
8143 {
8144 /* Once we've packed as many args as we have types, stop. */
8148 /* We don't know how many args we have yet, just
8149 use the unconverted ones for now. */
8151 else
8153 }
8156 {
8159 }
8160 else
8163 in_decl);
8167 }
8171 {
8176 }
8181 else
8182 {
8185 }
8192 }
8194 /* Returns the number of pack expansions in the template argument vector
8195 ARGS. */
8197 static int
8199 {
8204 {
8208 }
8210 }
8212 /* Convert all template arguments to their appropriate types, and
8213 return a vector containing the innermost resulting template
8214 arguments. If any error occurs, return error_mark_node. Error and
8215 warning messages are issued under control of COMPLAIN.
8217 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8218 for arguments not specified in ARGS. Otherwise, if
8219 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8220 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8221 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8222 ARGS. */
8224 static tree
8226 tree args,
8227 tree in_decl,
8228 tsubst_flags_t complain,
8231 {
8233 tree orig_inner_args;
8234 tree inner_args;
8235 tree new_args;
8236 tree new_inner_args;
8240 /* When used as a boolean value, indicates whether this is a
8241 variadic template parameter list. Since it's an int, we can also
8242 subtract it from nparms to get the number of non-variadic
8243 parameters. */
8248 /* Adjustment to nparms for fixed parameter packs. */
8253 /* Likewise for parameters with default arguments. */
8261 /* Determine if there are any parameter packs or default arguments. */
8263 {
8271 }
8274 /* If there are no parameters that follow a parameter pack, we need to
8275 expand any argument packs so that we can deduce a parameter pack from
8276 some non-packed args followed by an argument pack, as in variadic85.C.
8277 If there are such parameters, we need to leave argument packs intact
8278 so the arguments are assigned properly. This can happen when dealing
8279 with a nested class inside a partial specialization of a class
8280 template, as in variadic92.C, or when deducing a template parameter pack
8281 from a sub-declarator, as in variadic114.C. */
8285 /* Count any pack expansion args. */
8291 && require_all_args
8292 && !variadic_args_p
8293 && (!use_default_args
8296 {
8297 bad_nargs:
8299 {
8301 {
8305 }
8306 else
8313 }
8316 }
8317 /* We can't pass a pack expansion to a non-pack parameter of an alias
8318 template (DR 1430). */
8322 && variadic_args_p
8324 {
8326 {
8328 {
8334 {
8337 "pack expansion argument for non-pack parameter "
8339 else
8341 "pack expansion argument for non-pack parameter "
8345 }
8346 }
8348 found:;
8349 }
8351 }
8353 /* We need to evaluate the template arguments, even though this
8354 template-id may be nested within a "sizeof". */
8363 {
8364 tree arg;
8365 tree parm;
8367 /* Get the Ith template parameter. */
8371 {
8374 }
8376 /* Calculate the next argument. */
8379 else
8384 {
8385 /* Some arguments will be placed in the
8386 template parameter pack PARM. */
8393 {
8394 /* We don't know how many args we have yet, just use the
8395 unconverted (and still packed) ones for now. */
8399 }
8403 /* Store this argument. */
8405 {
8406 lost++;
8407 /* We are done with all of the arguments. */
8410 }
8411 else
8412 {
8416 {
8419 }
8420 }
8423 }
8425 {
8427 {
8428 /* "If every valid specialization of a variadic template
8429 requires an empty template parameter pack, the template is
8430 ill-formed, no diagnostic required." So check that the
8431 pattern works with this parameter. */
8436 in_decl);
8438 {
8443 }
8445 /* Recover from missing typename. */
8449 /* We don't know how many args we have yet, just
8450 use the unconverted ones for now. */
8454 }
8455 }
8457 {
8458 /* There must be a default arg in this case. */
8461 /* The position of the first default template argument,
8462 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8463 Record that. */
8467 }
8468 else
8472 {
8475 }
8477 {
8478 /* This can occur if there was an error in the template
8479 parameter list itself (which we would already have
8480 reported) that we are trying to recover from, e.g., a class
8481 template with a parameter list such as
8482 template<typename..., typename> (cpp0x/variadic150.C). */
8485 /* This can also happen with a fixed parameter pack (71834). */
8488 }
8489 else
8495 lost++;
8497 }
8502 {
8503 /* If we had fixed parameter packs, we didn't know how many arguments we
8504 actually needed earlier; now we do. */
8508 }
8511 {
8512 /* We had some pack expansion arguments that will only work if the packs
8513 are empty, but wait until instantiation time to complain.
8514 See variadic-ttp3.C. */
8524 }
8527 {
8530 }
8537 }
8539 /* Convert all template arguments to their appropriate types, and
8540 return a vector containing the innermost resulting template
8541 arguments. If any error occurs, return error_mark_node. Error and
8542 warning messages are not issued.
8544 Note that no function argument deduction is performed, and default
8545 arguments are used to fill in unspecified arguments. */
8546 tree
8548 {
8550 }
8552 /* Convert all template arguments to their appropriate type, and
8553 instantiate default arguments as needed. This returns a vector
8554 containing the innermost resulting template arguments, or
8555 error_mark_node if unsuccessful. */
8556 tree
8558 tsubst_flags_t complain)
8559 {
8561 }
8563 /* Like coerce_template_parms. If PARMS represents all template
8564 parameters levels, this function returns a vector of vectors
8565 representing all the resulting argument levels. Note that in this
8566 case, only the innermost arguments are coerced because the
8567 outermost ones are supposed to have been coerced already.
8569 Otherwise, if PARMS represents only (the innermost) vector of
8570 parameters, this function returns a vector containing just the
8571 innermost resulting arguments. */
8573 static tree
8575 tree args,
8576 tree in_decl,
8577 tsubst_flags_t complain,
8580 {
8583 tree coerced_args;
8586 {
8588 tree level;
8594 {
8595 tree l;
8599 require_all_args,
8600 use_default_args);
8601 else
8608 }
8609 }
8610 else
8613 require_all_args,
8614 use_default_args);
8616 }
8618 /* Returns 1 if template args OT and NT are equivalent. */
8620 int
8622 {
8631 /* For member templates */
8640 {
8657 }
8661 {
8664 /* Don't treat an alias template specialization with dependent
8665 arguments as equivalent to its underlying type when used as a
8666 template argument; we need them to be distinct so that we
8667 substitute into the specialization arguments at instantiation
8668 time. And aliases can't be equivalent without being ==, so
8669 we don't need to look any deeper.
8671 During partial ordering, however, we need to treat them normally so
8672 that we can order uses of the same alias with different
8673 cv-qualification (79960). */
8677 else
8679 }
8682 else
8683 {
8684 /* Try to treat a template non-type argument that has been converted
8685 to the parameter type as equivalent to one that hasn't yet. */
8698 }
8699 }
8701 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8702 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8703 NEWARG_PTR with the offending arguments if they are non-NULL. */
8705 int
8709 {
8722 {
8727 {
8733 }
8734 }
8736 }
8740 {
8742 }
8744 /* Implement a freelist interface for objects of type T.
8746 Head is a separate object, rather than a regular member, so that we
8747 can define it as a GTY deletable pointer, which is highly
8748 desirable. A data member could be declared that way, but then the
8749 containing object would implicitly get GTY((user)), which would
8750 prevent us from instantiating freelists as global objects.
8751 Although this way we can create freelist global objects, they're
8752 such thin wrappers that instantiating temporaries at every use
8753 loses nothing and saves permanent storage for the freelist object.
8755 Member functions next, anew, poison and reinit have default
8756 implementations that work for most of the types we're interested
8757 in, but if they don't work for some type, they should be explicitly
8758 specialized. See the comments before them for requirements, and
8759 the example specializations for the tree_list_freelist. */
8761 class freelist
8762 {
8763 /* Return the next object in a chain. We could just do type
8764 punning, but if we access the object with its underlying type, we
8765 avoid strict-aliasing trouble. This needs only work between
8766 poison and reinit. */
8769 /* Return a newly allocated, uninitialized or minimally-initialized
8770 object of type T. Any initialization performed by anew should
8771 either remain across the life of the object and the execution of
8772 poison, or be redone by reinit. */
8775 /* Optionally scribble all over the bits holding the object, so that
8776 they become (mostly?) uninitialized memory. This is called while
8777 preparing to make the object part of the free list. */
8782 #ifdef ENABLE_GC_CHECKING
8783 /* Poison the data, to indicate the data is garbage. */
8786 #endif
8787 /* Let valgrind know the object is free. */
8790 /* Let valgrind know the next portion of the object is available,
8791 but uninitialized. */
8793 }
8795 /* Bring an object that underwent at least one lifecycle after anew
8796 and before the most recent free and poison, back to a usable
8797 state, reinitializing whatever is needed for it to be
8798 functionally equivalent to an object just allocated and returned
8799 by anew. This may poison or clear the next field, used by
8800 freelist housekeeping after poison was called. */
8804 #ifdef ENABLE_GC_CHECKING
8806 #endif
8807 /* Let valgrind know the entire object is available, but
8808 uninitialized. */
8810 }
8812 /* Reference a GTY-deletable pointer that points to the first object
8813 in the free list proper. */
8816 /* Construct a freelist object chaining objects off of HEAD. */
8819 /* Add OBJ to the free object list. The former head becomes OBJ's
8820 successor. */
8822 {
8826 }
8828 /* Take an object from the free list, if one is available, or
8829 allocate a new one. Objects taken from the free list should be
8830 regarded as filled with garbage, except for bits that are
8831 configured to be preserved across free and alloc. */
8833 {
8835 {
8840 }
8841 else
8843 }
8844 };
8846 /* Explicitly specialize the interfaces for freelist<tree_node>: we
8847 want to allocate a TREE_LIST using the usual interface, and ensure
8848 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
8849 build_tree_list logic in reinit, so this could go out of sync. */
8853 {
8855 }
8857 inline tree
8859 {
8861 }
8865 {
8871 #ifdef ENABLE_GC_CHECKING
8874 /* Poison the data, to indicate the data is garbage. */
8877 #endif
8878 /* Let valgrind know the object is free. */
8880 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
8884 #ifdef ENABLE_GC_CHECKING
8886 /* Keep TREE_CHAIN functional. */
8888 #else
8890 #endif
8891 }
8895 {
8898 #ifdef ENABLE_GC_CHECKING
8902 #endif
8904 /* Let valgrind know the entire object is available, but
8905 uninitialized. */
8908 #ifdef ENABLE_GC_CHECKING
8910 #else
8912 #endif
8913 }
8915 /* Point to the first object in the TREE_LIST freelist. */
8917 /* Return the/an actual TREE_LIST freelist. */
8920 {
8922 }
8924 /* Point to the first object in the tinst_level freelist. */
8926 /* Return the/an actual tinst_level freelist. */
8929 {
8931 }
8933 /* Point to the first object in the pending_template freelist. */
8935 /* Return the/an actual pending_template freelist. */
8938 {
8940 }
8942 /* Build the TREE_LIST object out of a split list, store it
8943 permanently, and return it. */
8944 tree
8946 {
8955 }
8959 /* Increment OBJ's refcount unless it is already infinite. */
8962 {
8966 }
8968 /* Release storage for OBJ and node, if it's a TREE_LIST. */
8969 void
8971 {
8975 }
8977 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
8978 OBJ's DECL and OBJ, and start over with the tinst_level object that
8979 used to be referenced by OBJ's NEXT. */
8980 static void
8982 {
8986 {
8990 }
8991 }
8993 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
8994 and of the former PTR. Omitting the second argument is equivalent
8995 to passing (T*)NULL; this is allowed because passing the
8996 zero-valued integral constant NULL confuses type deduction and/or
8997 overload resolution. */
8999 static void
9001 {
9005 }
9007 static void
9009 {
9019 /* We are called both from instantiate_decl, where we've already had a
9020 tinst_level pushed, and instantiate_template, where we haven't.
9021 Compensate. */
9023 level = !current_tinst_level
9035 else
9044 }
9047 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9048 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9049 documentation for TEMPLATE_ID_EXPR. */
9051 tree
9053 {
9054 tree type;
9062 {
9065 }
9068 {
9070 unknown_type_node,
9072 arglist);
9074 }
9081 }
9083 /* Within the scope of a template class S<T>, the name S gets bound
9084 (in build_self_reference) to a TYPE_DECL for the class, not a
9085 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9086 or one of its enclosing classes, and that type is a template,
9087 return the associated TEMPLATE_DECL. Otherwise, the original
9088 DECL is returned.
9090 Also handle the case when DECL is a TREE_LIST of ambiguous
9091 injected-class-names from different bases. */
9093 tree
9095 {
9099 /* DR 176: A lookup that finds an injected-class-name (10.2
9100 [class.member.lookup]) can result in an ambiguity in certain cases
9101 (for example, if it is found in more than one base class). If all of
9102 the injected-class-names that are found refer to specializations of
9103 the same class template, and if the name is followed by a
9104 template-argument-list, the reference refers to the class template
9105 itself and not a specialization thereof, and is not ambiguous. */
9107 {
9110 {
9116 }
9119 else
9121 }
9127 }
9129 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9130 parameters, find the desired type.
9132 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
9134 IN_DECL, if non-NULL, is the template declaration we are trying to
9135 instantiate.
9137 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
9138 the class we are looking up.
9140 Issue error and warning messages under control of COMPLAIN.
9142 If the template class is really a local class in a template
9143 function, then the FUNCTION_CONTEXT is the function in which it is
9144 being instantiated.
9146 ??? Note that this function is currently called *twice* for each
9147 template-id: the first time from the parser, while creating the
9148 incomplete type (finish_template_type), and the second type during the
9149 real instantiation (instantiate_template_class). This is surely something
9150 that we want to avoid. It also causes some problems with argument
9151 coercion (see convert_nontype_argument for more information on this). */
9153 static tree
9156 {
9158 tree t;
9161 spec_entry elt;
9162 hashval_t hash;
9165 {
9169 else
9170 {
9177 }
9180 }
9182 {
9185 /* If we are declaring a constructor, say A<T>::A<T>, we will get
9186 an implicit typename for the second A. Deal with it. */
9191 {
9194 }
9195 }
9198 {
9201 }
9203 {
9207 }
9209 {
9212 }
9214 /* Issue an error message if we didn't find a template. */
9216 {
9220 }
9223 /* Make sure it's a user visible template, if it was named by
9224 the user. */
9227 {
9229 {
9233 }
9235 }
9239 /* An alias that just changes the name of a template is equivalent to the
9240 other template, so if any of the arguments are pack expansions, strip
9241 the alias to avoid problems with a pack expansion passed to a non-pack
9242 alias template parameter (DR 1430). */
9247 {
9248 tree parm;
9257 }
9258 else
9259 {
9261 tree gen_tmpl;
9262 tree type_decl;
9270 /* An error occurred while building the template TEMPL, and a
9271 diagnostic has most certainly been emitted for that
9272 already. Let's propagate that error. */
9281 {
9282 /* We've been given an incomplete set of template arguments.
9283 For example, given:
9285 template <class T> struct S1 {
9286 template <class U> struct S2 {};
9287 template <class U> struct S2<U*> {};
9288 };
9290 we will be called with an ARGLIST of `U*', but the
9291 TEMPLATE will be `template <class T> template
9292 <class U> struct S1<T>::S2'. We must fill in the missing
9293 arguments. */
9297 }
9299 /* Now we should have enough arguments. */
9302 /* From here on, we're only interested in the most general
9303 template. */
9305 /* Calculate the BOUND_ARGS. These will be the args that are
9306 actually tsubst'd into the definition to create the
9307 instantiation. */
9309 complain,
9314 /* We were unable to bind the arguments. */
9317 /* In the scope of a template class, explicit references to the
9318 template class refer to the type of the template, not any
9319 instantiation of it. For example, in:
9321 template <class T> class C { void f(C<T>); }
9323 the `C<T>' is just the same as `C'. Outside of the
9324 class, however, such a reference is an instantiation. */
9328 {
9333 }
9335 /* If we already have this specialization, return it. */
9345 /* If the the template's constraints are not satisfied,
9346 then we cannot form a valid type.
9348 Note that the check is deferred until after the hash
9349 lookup. This prevents redundant checks on previously
9350 instantiated specializations. */
9352 {
9354 {
9357 }
9359 }
9363 /* If the deduced arguments are invalid, then the binding
9364 failed. */
9368 complain))
9375 {
9380 }
9384 {
9387 }
9388 else
9397 /* Create the type. */
9399 {
9400 /* The user referred to a specialization of an alias
9401 template represented by GEN_TMPL.
9403 [temp.alias]/2 says:
9405 When a template-id refers to the specialization of an
9406 alias template, it is equivalent to the associated
9407 type obtained by substitution of its
9408 template-arguments for the template-parameters in the
9409 type-id of the alias template. */
9412 /* Note that the call above (by indirectly calling
9413 register_specialization in tsubst_decl) registers the
9414 TYPE_DECL representing the specialization of the alias
9415 template. So next time someone substitutes ARGLIST for
9416 the template parms into the alias template (GEN_TMPL),
9417 she'll get that TYPE_DECL back. */
9421 }
9423 {
9425 {
9436 }
9437 else
9438 {
9439 /* We don't want to call start_enum for this type, since
9440 the values for the enumeration constants may involve
9441 template parameters. And, no one should be interested
9442 in the enumeration constants for such a type. */
9445 }
9449 }
9451 {
9452 /* Lambda closures are regenerated in tsubst_lambda_expr, not
9453 instantiated here. */
9461 /* A local class. Make sure the decl gets registered properly. */
9468 /* This instantiation is another name for the primary
9469 template type. Set the TYPE_CANONICAL field
9470 appropriately. */
9473 /* Some of the template arguments require structural
9474 equality testing, so this template class requires
9475 structural equality testing. */
9477 }
9478 else
9481 /* If we called start_enum or pushtag above, this information
9482 will already be set up. */
9484 {
9491 }
9492 else
9496 {
9502 {
9505 }
9506 }
9510 {
9514 {
9515 tree attributes
9523 }
9524 }
9526 /* Let's consider the explicit specialization of a member
9527 of a class template specialization that is implicitly instantiated,
9528 e.g.:
9529 template<class T>
9530 struct S
9531 {
9532 template<class U> struct M {}; //#0
9533 };
9535 template<>
9536 template<>
9537 struct S<int>::M<char> //#1
9538 {
9539 int i;
9540 };
9541 [temp.expl.spec]/4 says this is valid.
9543 In this case, when we write:
9544 S<int>::M<char> m;
9546 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9547 the one of #0.
9549 When we encounter #1, we want to store the partial instantiation
9550 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9552 For all cases other than this "explicit specialization of member of a
9553 class template", we just want to store the most general template into
9554 the CLASSTYPE_TI_TEMPLATE of M.
9556 This case of "explicit specialization of member of a class template"
9557 only happens when:
9558 1/ the enclosing class is an instantiation of, and therefore not
9559 the same as, the context of the most general template, and
9560 2/ we aren't looking at the partial instantiation itself, i.e.
9561 the innermost arguments are not the same as the innermost parms of
9562 the most general template.
9564 So it's only when 1/ and 2/ happens that we want to use the partial
9565 instantiation of the member template in lieu of its most general
9566 template. */
9570 /* the enclosing class must be an instantiation... */
9573 {
9577 tree partial_inst_args =
9584 use_partial_inst_tmpl =
9585 /*...and we must not be looking at the partial instantiation
9586 itself. */
9588 partial_inst_args);
9589 }
9592 /* This case is easy; there are no member templates involved. */
9594 else
9595 {
9596 /* This is a full instantiation of a member template. Find
9597 the partial instantiation of which this is an instance. */
9599 /* Temporarily reduce by one the number of levels in the ARGLIST
9600 so as to avoid comparing the last set of arguments. */
9604 /* FOUND is either a proper class type, or an alias
9605 template specialization. In the later case, it's a
9606 TYPE_DECL, resulting from the substituting of arguments
9607 for parameters in the TYPE_DECL of the alias template
9608 done earlier. So be careful while getting the template
9609 of FOUND. */
9611 ? found
9615 }
9617 // Build template info for the new specialization.
9626 /* Note this use of the partial instantiation so we can check it
9627 later in maybe_process_partial_specialization. */
9634 /* Now that the type has been registered on the instantiations
9635 list, we set up the enumerators. Because the enumeration
9636 constants may involve the enumeration type itself, we make
9637 sure to register the type first, and then create the
9638 constants. That way, doing tsubst_expr for the enumeration
9639 constants won't result in recursive calls here; we'll find
9640 the instantiation and exit above. */
9644 /* If the type makes use of template parameters, the
9645 code that generates debugging information will crash. */
9648 /* Possibly limit visibility based on template args. */
9655 }
9656 }
9658 /* Wrapper for lookup_template_class_1. */
9660 tree
9663 {
9664 tree ret;
9670 }
9672 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9674 tree
9676 {
9677 /* The type of the expression is NULL_TREE since the template-id could refer
9678 to an explicit or partial specialization. */
9681 /* Except that concepts are always bool. */
9684 }
9686 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9688 tree
9690 {
9694 /* We never want to return a VAR_DECL for a variable concept, since they
9695 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9710 {
9712 {
9715 }
9717 }
9719 /* If a template-id refers to a specialization of a variable
9720 concept, then the expression is true if and only if the
9721 concept's constraints are satisfied by the given template
9722 arguments.
9724 NOTE: This is an extension of Concepts Lite TS that
9725 allows constraints to be used in expressions. */
9727 {
9730 }
9733 }
9735 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9736 TARGS template args, and instantiate it if it's not dependent. */
9738 tree
9740 tsubst_flags_t complain)
9741 {
9744 {
9747 }
9750 }
9752 \f
9753 struct pair_fn_data
9754 {
9755 tree_fn_t fn;
9756 tree_fn_t any_fn;
9758 /* True when we should also visit template parameters that occur in
9759 non-deduced contexts. */
9762 };
9764 /* Called from for_each_template_parm via walk_tree. */
9766 static tree
9768 {
9775 #define WALK_SUBTREE(NODE) \
9776 do \
9777 { \
9778 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9779 pfd->include_nondeduced_p, \
9780 pfd->any_fn); \
9781 if (result) goto out; \
9782 } \
9783 while (0)
9793 {
9797 /* Fall through. */
9803 else
9813 /* Since we're not going to walk subtrees, we have to do this
9814 explicitly here. */
9816 /* Fall through. */
9819 /* Check the return type. */
9822 /* Check the parameter types. Since default arguments are not
9823 instantiated until they are needed, the TYPE_ARG_TYPES may
9824 contain expressions that involve template parameters. But,
9825 no-one should be looking at them yet. And, once they're
9826 instantiated, they don't contain template parameters, so
9827 there's no point in looking at them then, either. */
9828 {
9829 tree parm;
9834 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9835 want walk_tree walking into them itself. */
9837 }
9840 {
9844 }
9863 /* Fall through. */
9875 /* Record template parameters such as `T' inside `TT<T>'. */
9877 /* Fall through. */
9889 /* A template template parameter is encountered. */
9893 /* Already substituted template template parameter */
9898 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9899 partial instantiation. */
9911 /* If there's no type, then this thing must be some expression
9912 involving template parameters. */
9934 }
9936 #undef WALK_SUBTREE
9938 /* We didn't find any template parameters we liked. */
9939 out:
9941 }
9943 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9944 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9945 call FN with the parameter and the DATA.
9946 If FN returns nonzero, the iteration is terminated, and
9947 for_each_template_parm returns 1. Otherwise, the iteration
9948 continues. If FN never returns a nonzero value, the value
9949 returned by for_each_template_parm is 0. If FN is NULL, it is
9950 considered to be the function which always returns 1.
9952 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9953 parameters that occur in non-deduced contexts. When false, only
9954 visits those template parameters that can be deduced. */
9956 static tree
9960 tree_fn_t any_fn)
9961 {
9963 tree result;
9965 /* Set up. */
9971 /* Walk the tree. (Conceptually, we would like to walk without
9972 duplicates, but for_each_template_parm_r recursively calls
9973 for_each_template_parm, so we would need to reorganize a fair
9974 bit to use walk_tree_without_duplicates, so we keep our own
9975 visited list.) */
9978 else
9981 for_each_template_parm_r,
9985 /* Clean up. */
9987 {
9990 }
9993 }
9995 /* Returns true if T depends on any template parameter. */
9997 int
9999 {
10029 else
10030 {
10033 }
10038 }
10040 /* Returns true iff current_function_decl is an incompletely instantiated
10041 template. Useful instead of processing_template_decl because the latter
10042 is set to 0 during instantiate_non_dependent_expr. */
10044 bool
10046 {
10055 }
10057 /* Returns true if T depends on any template parameter with level LEVEL. */
10059 bool
10061 {
10064 }
10066 /* Returns true if the signature of DECL depends on any template parameter from
10067 its enclosing class. */
10069 bool
10071 {
10081 template_parm_outer_level,
10091 }
10093 /* Returns TRUE iff INST is an instantiation we don't need to do in an
10094 ill-formed translation unit, i.e. a variable or function that isn't
10095 usable in a constant expression. */
10099 {
10104 }
10106 /* Returns TRUE iff we should refuse to instantiate DECL because it's
10107 neglectable and instantiated from within an erroneous instantiation. */
10109 static bool
10111 {
10122 }
10130 /* We're starting to instantiate D; record the template instantiation context
10131 at LOC for diagnostics and to restore it later. */
10133 static bool
10135 {
10139 {
10140 /* Tell error.c not to try to instantiate any templates. */
10143 "template instantiation depth exceeds maximum of %d"
10145 max_tinst_depth);
10147 }
10149 /* If the current instantiation caused problems, don't let it instantiate
10150 anything else. Do allow deduction substitution and decls usable in
10151 constant expressions. */
10155 /* When not -quiet, dump template instantiations other than functions, since
10156 announce_function will take care of those. */
10177 }
10179 /* We're starting substitution of TMPL<ARGS>; record the template
10180 substitution context for diagnostics and to restore it later. */
10182 static bool
10184 {
10186 }
10188 /* We're starting to instantiate D; record INPUT_LOCATION and the
10189 template instantiation context for diagnostics and to restore it
10190 later. */
10192 bool
10194 {
10196 }
10198 /* Likewise, but record LOC as the program location. */
10200 bool
10202 {
10205 }
10207 /* We're done instantiating this template; return to the instantiation
10208 context. */
10210 void
10212 {
10213 /* Restore the filename and line number stashed away when we started
10214 this instantiation. */
10218 }
10220 /* We're instantiating a deferred template; restore the template
10221 instantiation context in which the instantiation was requested, which
10222 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
10224 static tree
10226 {
10238 }
10240 /* Returns the TINST_LEVEL which gives the original instantiation
10241 context. */
10245 {
10251 }
10253 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
10254 vector of template arguments, as for tsubst.
10256 Returns an appropriate tsubst'd friend declaration. */
10258 static tree
10260 {
10261 tree new_friend;
10266 /* This was a friend declared with an explicit template
10267 argument list, e.g.:
10269 friend void f<>(T);
10271 to indicate that f was a template instantiation, not a new
10272 function declaration. Now, we have to figure out what
10273 instantiation of what template. */
10274 {
10276 tree new_args;
10277 tree tmpl;
10280 /* Friend functions are looked up in the containing namespace scope.
10281 We must enter that scope, to avoid finding member functions of the
10282 current class with same name. */
10297 tsk_none);
10299 }
10303 /* The NEW_FRIEND will look like an instantiation, to the
10304 compiler, but is not an instantiation from the point of view of
10305 the language. For example, we might have had:
10307 template <class T> struct S {
10308 template <class U> friend void f(T, U);
10309 };
10311 Then, in S<int>, template <class U> void f(int, U) is not an
10312 instantiation of anything. */
10318 {
10322 }
10324 /* The mangled name for the NEW_FRIEND is incorrect. The function
10325 is not a template instantiation and should not be mangled like
10326 one. Therefore, we forget the mangling here; we'll recompute it
10327 later if we need it. */
10329 {
10332 }
10335 {
10336 tree old_decl;
10337 tree new_friend_template_info;
10338 tree new_friend_result_template_info;
10339 tree ns;
10342 /* We must save some information from NEW_FRIEND before calling
10343 duplicate decls since that function will free NEW_FRIEND if
10344 possible. */
10346 new_friend_is_defn =
10351 {
10352 /* This declaration is a `primary' template. */
10355 new_friend_result_template_info
10357 }
10358 else
10361 /* Inside pushdecl_namespace_level, we will push into the
10362 current namespace. However, the friend function should go
10363 into the namespace of the template. */
10373 {
10374 /* This new friend declaration matched an existing
10375 declaration. For example, given:
10377 template <class T> void f(T);
10378 template <class U> class C {
10379 template <class T> friend void f(T) {}
10380 };
10382 the friend declaration actually provides the definition
10383 of `f', once C has been instantiated for some type. So,
10384 old_decl will be the out-of-class template declaration,
10385 while new_friend is the in-class definition.
10387 But, if `f' was called before this point, the
10388 instantiation of `f' will have DECL_TI_ARGS corresponding
10389 to `T' but not to `U', references to which might appear
10390 in the definition of `f'. Previously, the most general
10391 template for an instantiation of `f' was the out-of-class
10392 version; now it is the in-class version. Therefore, we
10393 run through all specialization of `f', adding to their
10394 DECL_TI_ARGS appropriately. In particular, they need a
10395 new set of outer arguments, corresponding to the
10396 arguments for this class instantiation.
10398 The same situation can arise with something like this:
10400 friend void f(int);
10401 template <class T> class C {
10402 friend void f(T) {}
10403 };
10405 when `C<int>' is instantiated. Now, `f(int)' is defined
10406 in the class. */
10409 /* On the other hand, if the in-class declaration does
10410 *not* provide a definition, then we don't want to alter
10411 existing definitions. We can just leave everything
10412 alone. */
10413 ;
10414 else
10415 {
10419 /* Overwrite whatever template info was there before, if
10420 any, with the new template information pertaining to
10421 the declaration. */
10425 {
10426 /* We should have called reregister_specialization in
10427 duplicate_decls. */
10432 /* Instantiate it if the global has already been used. */
10436 }
10437 else
10438 {
10439 tree t;
10441 /* Indicate that the old function template is a partial
10442 instantiation. */
10450 /* Reassign any specializations already in the hash table
10451 to the new more general template, and add the
10452 additional template args. */
10456 {
10458 spec_entry elt;
10470 register_specialization
10473 }
10475 }
10476 }
10478 /* The information from NEW_FRIEND has been merged into OLD_DECL
10479 by duplicate_decls. */
10481 }
10482 }
10483 else
10484 {
10488 /* In the code
10489 template <class T> class C {
10490 template <class U> friend void C1<U>::f (); // case 1
10491 friend void C2<T>::f (); // case 2
10492 };
10493 we only need to make sure CONTEXT is a complete type for
10494 case 2. To distinguish between the two cases, we note that
10495 CONTEXT of case 1 remains dependent type after tsubst while
10496 this isn't true for case 2. */
10506 {
10508 /* do_friend adds the TEMPLATE_DECL for any member friend
10509 template even if it isn't a member template, i.e.
10510 template <class T> friend A<T>::f();
10511 Look through it in that case. */
10515 /* Check to see that the declaration is really present, and,
10516 possibly obtain an improved declaration. */
10521 }
10522 }
10525 }
10527 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10528 template arguments, as for tsubst.
10530 Returns an appropriate tsubst'd friend type or error_mark_node on
10531 failure. */
10533 static tree
10535 {
10536 tree tmpl;
10539 {
10542 }
10547 else
10555 {
10556 /* The friend template has already been declared. Just
10557 check to see that the declarations match, and install any new
10558 default parameters. We must tsubst the default parameters,
10559 of course. We only need the innermost template parameters
10560 because that is all that redeclare_class_template will look
10561 at. */
10564 {
10572 }
10573 }
10574 else
10575 {
10576 /* The friend template has not already been declared. In this
10577 case, the instantiation of the template class will cause the
10578 injection of this template into the namespace scope. */
10582 {
10583 /* The new TMPL is not an instantiation of anything, so we
10584 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10585 for the new type because that is supposed to be the
10586 corresponding template decl, i.e., TMPL. */
10593 /* It is hidden. */
10598 /* Inject this template into the enclosing namspace scope. */
10600 }
10601 }
10605 else
10609 }
10611 /* Returns zero if TYPE cannot be completed later due to circularity.
10612 Otherwise returns one. */
10614 static int
10616 {
10626 else
10628 }
10633 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10634 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10636 static tree
10639 {
10648 {
10655 clauses
10659 else
10661 }
10662 /* If the first attribute argument is an identifier, don't
10663 pass it through tsubst. Attributes like mode, format,
10664 cleanup and several target specific attributes expect it
10665 unmodified. */
10667 {
10668 tree chain
10673 }
10675 {
10676 /* An attribute pack expansion. */
10685 {
10689 }
10691 }
10692 else
10699 }
10701 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10702 unchanged or a new TREE_LIST chain. */
10704 static tree
10707 {
10712 {
10716 }
10720 {
10723 {
10726 {
10732 }
10733 }
10735 }
10738 }
10740 /* Apply any attributes which had to be deferred until instantiation
10741 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10742 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10744 static void
10747 {
10749 tree t;
10756 {
10760 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10761 to our attributes parameter. */
10763 }
10764 else
10765 {
10767 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10768 lookup_template_class_1, and should be preserved. */
10772 }
10776 {
10780 }
10784 {
10789 {
10792 {
10798 }
10799 else
10801 }
10804 }
10805 }
10807 /* Perform (or defer) access check for typedefs that were referenced
10808 from within the template TMPL code.
10809 This is a subroutine of instantiate_decl and instantiate_class_template.
10810 TMPL is the template to consider and TARGS is the list of arguments of
10811 that template. */
10813 static void
10815 {
10816 location_t saved_location;
10827 {
10839 /* Make access check error messages point to the location
10840 of the use of the typedef. */
10844 tf_warning_or_error);
10845 }
10847 }
10849 static tree
10851 {
10853 tree typedecl;
10854 tree pbinfo;
10855 tree base_list;
10857 tree fn_context;
10866 /* Figure out which template is being instantiated. */
10870 /* Mark the type as in the process of being defined. */
10873 /* We may be in the middle of deferred access check. Disable
10874 it now. */
10877 /* Determine what specialization of the original template to
10878 instantiate. */
10883 {
10884 /* This TYPE is actually an instantiation of a partial
10885 specialization. We replace the innermost set of ARGS with
10886 the arguments appropriate for substitution. For example,
10887 given:
10889 template <class T> struct S {};
10890 template <class T> struct S<T*> {};
10892 and supposing that we are instantiating S<int*>, ARGS will
10893 presently be {int*} -- but we need {int}. */
10896 }
10897 else
10898 {
10901 }
10903 /* If the template we're instantiating is incomplete, then clearly
10904 there's nothing we can do. */
10906 {
10907 /* We can try again later. */
10910 }
10912 /* If we've recursively instantiated too many templates, stop. */
10920 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10925 else
10926 {
10929 }
10930 /* Use #pragma pack from the template context. */
10936 /* Set the input location to the most specialized template definition.
10937 This is needed if tsubsting causes an error. */
10949 {
10952 /* Adjust visibility for template arguments. */
10954 }
10960 /* We should never instantiate a nested class before its enclosing
10961 class; we need to look up the nested class by name before we can
10962 instantiate it, and that lookup should instantiate the enclosing
10963 class. */
10969 {
10970 tree pbase_binfo;
10971 tree pushed_scope;
10974 /* We must enter the scope containing the type, as that is where
10975 the accessibility of types named in dependent bases are
10976 looked up from. */
10979 /* Substitute into each of the bases to determine the actual
10980 basetypes. */
10982 {
10983 tree base;
10989 {
10990 expanded_bases =
10997 }
11000 {
11002 /* Extract the already-expanded base class. */
11004 else
11005 /* Substitute to figure out the base class. */
11007 NULL_TREE);
11015 }
11016 }
11018 /* The list is now in reverse order; correct that. */
11023 }
11024 /* Now call xref_basetypes to set up all the base-class
11025 information. */
11033 /* Now that our base classes are set up, enter the scope of the
11034 class, so that name lookups into base classes, etc. will work
11035 correctly. This is precisely analogous to what we do in
11036 begin_class_definition when defining an ordinary non-template
11037 class, except we also need to push the enclosing classes. */
11040 /* Now members are processed in the order of declaration. */
11043 {
11047 {
11049 {
11051 /* A closure type for a lambda in an NSDMI or default argument.
11052 Ignore it; it will be regenerated when needed. */
11055 /* Build new CLASSTYPE_NESTED_UTDS. */
11057 tree newtag;
11063 /* If the member is a class template, then -- even after
11064 substitution -- there may be dependent types in the
11065 template argument list for the class. We increment
11066 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
11067 that function will assume that no types are dependent
11068 when outside of a template. */
11078 {
11082 /* Unfortunately, lookup_template_class sets
11083 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
11084 instantiation (i.e., for the type of a member
11085 template class nested within a template class.)
11086 This behavior is required for
11087 maybe_process_partial_specialization to work
11088 correctly, but is not accurate in this case;
11089 the TAG is not an instantiation of anything.
11090 (The corresponding TEMPLATE_DECL is an
11091 instantiation, but the TYPE is not.) */
11094 /* Now, we call pushtag to put this NEWTAG into the scope of
11095 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
11096 pushtag calling push_template_decl. We don't have to do
11097 this for enums because it will already have been done in
11098 tsubst_enum. */
11102 }
11103 }
11105 {
11106 tree r;
11115 /* Instantiate members marked with attribute used. */
11121 }
11124 /* A closure type for a lambda in an NSDMI or default argument.
11126 else
11127 {
11128 /* Build new TYPE_FIELDS. */
11130 {
11131 tree condition;
11134 condition =
11144 }
11146 {
11147 tree r;
11151 /* The file and line for this declaration, to
11152 assist in error message reporting. Since we
11153 called push_tinst_level above, we don't need to
11154 restore these. */
11164 {
11165 /* A capture pack became multiple fields. */
11168 }
11171 {
11175 {
11176 /* In [temp.inst]:
11178 [t]he initialization (and any associated
11179 side-effects) of a static data member does
11180 not occur unless the static data member is
11181 itself used in a way that requires the
11182 definition of the static data member to
11183 exist.
11185 Therefore, we do not substitute into the
11186 initialized for the static data member here. */
11187 finish_static_data_member_decl
11193 /* Instantiate members marked with attribute used. */
11196 }
11198 {
11199 /* Determine whether R has a valid type and can be
11200 completed later. If R is invalid, then its type
11201 is replaced by error_mark_node. */
11207 {
11208 /* If R's type couldn't be completed and
11209 it isn't a flexible array member (whose
11210 type is incomplete by definition) give
11211 an error. */
11214 }
11219 {
11222 }
11223 }
11225 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
11226 such a thing will already have been added to the field
11227 list by tsubst_enum in finish_member_declaration in the
11228 CLASSTYPE_NESTED_UTDS case above. */
11232 {
11235 }
11236 }
11237 }
11238 }
11239 }
11240 else
11241 {
11244 {
11245 /* Build new CLASSTYPE_FRIEND_CLASSES. */
11251 {
11252 /* template <class T> friend class C; */
11255 }
11257 {
11258 /* template <class T> friend class C::D; */
11264 }
11267 {
11268 /* This could be either
11270 friend class T::C;
11272 when dependent_type_p is false or
11274 template <class U> friend class T::C;
11276 otherwise. */
11277 /* Bump processing_template_decl in case this is something like
11278 template <class T> friend struct A<T>::B. */
11285 }
11289 {
11290 /* friend class C;
11292 where C hasn't been declared yet. Let's lookup name
11293 from namespace scope directly, bypassing any name that
11294 come from dependent base class. */
11297 /* The call to xref_tag_from_type does injection for friend
11298 classes. */
11300 friend_type =
11304 }
11306 /* friend class C<T>; */
11309 /* Otherwise it's
11311 friend class C;
11313 where C is already declared or
11315 friend class C<int>;
11317 We don't have to do anything in these cases. */
11320 /* Trick make_friend_class into realizing that the friend
11321 we're adding is a template, not an ordinary class. It's
11322 important that we use make_friend_class since it will
11323 perform some error-checking and output cross-reference
11324 information. */
11332 }
11333 else
11334 {
11335 /* Build new DECL_FRIENDLIST. */
11336 tree r;
11338 /* The file and line for this declaration, to
11339 assist in error message reporting. Since we
11340 called push_tinst_level above, we don't need to
11341 restore these. */
11345 {
11348 }
11353 {
11356 }
11357 }
11358 }
11359 }
11362 {
11363 /* Restore these before substituting into the lambda capture
11364 initializers. */
11367 }
11369 /* Set the file and line number information to whatever is given for
11370 the class itself. This puts error messages involving generated
11371 implicit functions at a predictable point, and the same point
11372 that would be used for non-template classes. */
11379 /* We don't instantiate default arguments for member functions. 14.7.1:
11381 The implicit instantiation of a class template specialization causes
11382 the implicit instantiation of the declarations, but not of the
11383 definitions or default arguments, of the class member functions,
11384 member classes, static data members and member templates.... */
11386 /* Some typedefs referenced from within the template code need to be access
11387 checked at template instantiation time, i.e now. These types were
11388 added to the template at parsing time. Let's get those and perform
11389 the access checks then. */
11398 /* The vtable for a template class can be emitted in any translation
11399 unit in which the class is instantiated. When there is no key
11400 method, however, finish_struct_1 will already have added TYPE to
11401 the keyed_classes. */
11406 }
11408 /* Wrapper for instantiate_class_template_1. */
11410 tree
11412 {
11413 tree ret;
11418 }
11420 static tree
11422 {
11423 tree r;
11429 else
11430 {
11437 }
11439 }
11441 /* Given a function parameter pack TMPL_PARM and some function parameters
11442 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
11443 and set *SPEC_P to point at the next point in the list. */
11445 tree
11447 {
11448 /* Collect all of the extra "packed" parameters into an
11449 argument pack. */
11450 tree parmvec;
11460 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
11464 {
11469 }
11471 /* Build the argument packs. */
11476 }
11478 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
11479 NONTYPE_ARGUMENT_PACK. */
11481 static tree
11483 {
11485 }
11487 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
11488 pack expansion with no extra args, 2 if it has extra args, or 0
11489 if it is not a pack expansion. */
11491 static int
11493 {
11499 /* A decl pack is itself an expansion. */
11506 }
11509 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11511 static tree
11513 {
11520 }
11522 /* This is a subroutine of tsubst_pack_expansion.
11524 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11525 mechanism to store the (non complete list of) arguments of the
11526 substitution and return a non substituted pack expansion, in order
11527 to wait for when we have enough arguments to really perform the
11528 substitution. */
11530 static bool
11534 {
11535 /* If one pack has an expansion and another pack has a normal
11536 argument or if one pack has an empty argument and an another
11537 one hasn't then tsubst_pack_expansion cannot perform the
11538 substitution and need to fall back on the
11539 PACK_EXPANSION_EXTRA mechanism. */
11547 {
11550 parm_pack;
11552 {
11557 /* We can't substitute a pack expansion with extra args into
11558 our pattern. */
11562 else
11564 }
11568 }
11570 }
11572 /* [temp.variadic]/6 says that:
11574 The instantiation of a pack expansion [...]
11575 produces a list E1,E2, ..., En, where N is the number of elements
11576 in the pack expansion parameters.
11578 This subroutine of tsubst_pack_expansion produces one of these Ei.
11580 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11581 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11582 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11583 INDEX is the index 'i' of the element Ei to produce. ARGS,
11584 COMPLAIN, and IN_DECL are the same parameters as for the
11585 tsubst_pack_expansion function.
11587 The function returns the resulting Ei upon successful completion,
11588 or error_mark_node.
11590 Note that this function possibly modifies the ARGS parameter, so
11591 it's the responsibility of the caller to restore it. */
11593 static tree
11595 tree parm_packs,
11597 tree args /* This parm gets
11599 tsubst_flags_t complain,
11600 tree in_decl)
11601 {
11602 tree t;
11605 /* For each parameter pack, change the substitution of the parameter
11606 pack to the ith argument in its argument pack, then expand the
11607 pattern. */
11609 {
11614 ith_elem_is_expansion |=
11617 /* Select the Ith argument from the pack. */
11621 {
11623 {
11628 }
11629 else
11631 }
11632 else
11633 {
11638 {
11640 /* Update the corresponding argument. */
11642 }
11643 else
11644 /* Re-use the ARGUMENT_PACK_SELECT. */
11646 }
11648 }
11650 /* Substitute into the PATTERN with the (possibly altered)
11651 arguments. */
11653 /* Expanding a fixed parameter pack from
11654 coerce_template_parameter_pack. */
11659 {
11662 else
11665 }
11669 else
11672 /* If the Ith argument pack element is a pack expansion, then
11673 the Ith element resulting from the substituting is going to
11674 be a pack expansion as well. */
11679 }
11681 /* When the unexpanded parameter pack in a fold expression expands to an empty
11682 sequence, the value of the expression is as follows; the program is
11683 ill-formed if the operator is not listed in this table.
11685 && true
11686 || false
11687 , void() */
11689 tree
11691 {
11695 {
11704 }
11710 }
11712 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11713 form an expression that combines the two terms using the
11714 operator of T. */
11716 static tree
11718 {
11722 // Handle compound assignment operators.
11727 {
11737 complain);
11738 }
11739 }
11741 /* Substitute ARGS into the pack of a fold expression T. */
11745 {
11747 }
11749 /* Substitute ARGS into the pack of a fold expression T. */
11753 {
11755 }
11757 /* Expand a PACK of arguments into a grouped as left fold.
11758 Given a pack containing elements A0, A1, ..., An and an
11759 operator @, this builds the expression:
11761 ((A0 @ A1) @ A2) ... @ An
11763 Note that PACK must not be empty.
11765 The operator is defined by the original fold expression T. */
11767 static tree
11769 {
11772 {
11775 }
11777 }
11779 /* Substitute into a unary left fold expression. */
11781 static tree
11783 tree in_decl)
11784 {
11789 {
11793 }
11796 else
11798 }
11800 /* Substitute into a binary left fold expression.
11802 Do ths by building a single (non-empty) vector of argumnts and
11803 building the expression from those elements. */
11805 static tree
11807 tree in_decl)
11808 {
11817 {
11822 }
11830 }
11832 /* Expand a PACK of arguments into a grouped as right fold.
11833 Given a pack containing elementns A0, A1, ..., and an
11834 operator @, this builds the expression:
11836 A0@ ... (An-2 @ (An-1 @ An))
11838 Note that PACK must not be empty.
11840 The operator is defined by the original fold expression T. */
11842 tree
11844 {
11845 // Build the expression.
11849 {
11852 }
11854 }
11856 /* Substitute into a unary right fold expression. */
11858 static tree
11860 tree in_decl)
11861 {
11866 {
11870 }
11873 else
11875 }
11877 /* Substitute into a binary right fold expression.
11879 Do ths by building a single (non-empty) vector of arguments and
11880 building the expression from those elements. */
11882 static tree
11884 tree in_decl)
11885 {
11894 {
11899 }
11908 }
11910 /* Walk through the pattern of a pack expansion, adding everything in
11911 local_specializations to a list. */
11913 struct el_data
11914 {
11916 tree extra;
11917 tsubst_flags_t complain;
11921 };
11922 static tree
11924 {
11930 /* Remember local typedefs (85214). */
11936 {
11938 /* Don't mess with variables declared within the pattern. */
11941 {
11942 /* Maybe pull out the PARM_DECL for a partial instantiation. */
11945 {
11951 }
11953 {
11954 /* Handle lambda capture here, since we aren't doing any
11955 substitution now, and so tsubst_copy won't call
11956 process_outer_var_ref. */
11960 {
11966 {
11967 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
11968 proxies. */
11970 {
11975 }
11977 }
11978 }
11979 }
11980 }
11984 }
11986 }
11987 static tree
11989 {
11993 }
11995 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
11996 for use in PACK_EXPANSION_EXTRA_ARGS. */
11998 tree
12000 {
12006 }
12008 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
12009 normal template args to ARGS. */
12011 tree
12013 {
12015 {
12017 {
12018 /* The partial instantiation involved local declarations collected in
12019 extract_local_specs; map from the general template to our local
12020 context. */
12026 /* else inst is already a full instantiation of the pack. */
12028 }
12031 }
12033 }
12035 /* Substitute ARGS into T, which is an pack expansion
12036 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
12037 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
12038 (if only a partial substitution could be performed) or
12039 ERROR_MARK_NODE if there was an error. */
12040 tree
12042 tree in_decl)
12043 {
12044 tree pattern;
12049 tree result;
12057 /* Add in any args remembered from an earlier partial instantiation. */
12062 /* Determine the argument packs that will instantiate the parameter
12063 packs used in the expansion expression. While we're at it,
12064 compute the number of arguments to be expanded and make sure it
12065 is consistent. */
12068 {
12075 {
12081 complain);
12082 else
12086 }
12088 {
12090 {
12093 parm_pack);
12095 }
12098 }
12100 {
12101 /* We know we have correct local_specializations if this
12102 expansion is at function scope, or if we're dealing with a
12103 local parameter in a requires expression; for the latter,
12104 tsubst_requires_expr set it up appropriately. */
12107 else
12108 /* We can't rely on local_specializations for a parameter
12109 name used later in a function declaration (such as in a
12110 late-specified return type). Even if it exists, it might
12111 have the wrong value for a recursive call. */
12115 {
12116 /* This parameter pack was used in an unevaluated context. Just
12117 make a dummy decl, since it's only used for its type. */
12122 /* Partial instantiation of the parm_pack, we can't build
12123 up an argument pack yet. */
12125 else
12127 }
12129 /* This argument pack isn't fully instantiated yet. We set this
12130 flag rather than clear arg_pack because we do want to do the
12131 optimization below, and we don't want to substitute directly
12132 into the pattern (as that would expose a NONTYPE_ARGUMENT_PACK
12133 where it isn't expected). */
12135 }
12137 {
12141 }
12142 else
12143 {
12149 }
12156 /* This can only happen if we forget to expand an argument
12157 pack somewhere else. Just return an error, silently. */
12158 {
12162 }
12165 {
12169 /* Don't bother trying to do a partial substitution with
12170 incomplete packs; we'll try again after deduction. */
12178 {
12183 pattern);
12184 else
12186 pattern);
12188 }
12190 /* Keep track of the parameter packs and their corresponding
12191 argument packs. */
12194 }
12195 else
12196 {
12197 /* We can't substitute for this parameter pack. We use a flag as
12198 well as the missing_level counter because function parameter
12199 packs don't have a level. */
12202 }
12203 }
12205 /* If the expansion is just T..., return the matching argument pack, unless
12206 we need to call convert_from_reference on all the elements. This is an
12207 important optimization; see c++/68422. */
12210 {
12213 /* If the argument pack is a single pack expansion, pull it out. */
12218 /* Types need no adjustment, nor does sizeof..., and if we still have
12219 some pack expansion args we won't do anything yet. */
12224 /* Also optimize expression pack expansions if we can tell that the
12225 elements won't have reference type. */
12231 /* Otherwise use the normal path so we get convert_from_reference. */
12232 }
12234 /* We cannot expand this expansion expression, because we don't have
12235 all of the argument packs we need. */
12237 {
12238 /* We got some full packs, but we can't substitute them in until we
12239 have values for all the packs. So remember these until then. */
12245 }
12247 {
12248 /* There were no real arguments, we're just replacing a parameter
12249 pack with another version of itself. Substitute into the
12250 pattern and return a PACK_EXPANSION_*. The caller will need to
12251 deal with that. */
12255 else
12259 }
12264 {
12265 /* We're in a late-specified return type, so create our own local
12266 specializations map; the current map is either NULL or (in the
12267 case of recursive unification) might have bindings that we don't
12268 want to use or alter. */
12271 }
12273 /* For each argument in each argument pack, substitute into the
12274 pattern. */
12278 {
12280 i,
12282 in_decl);
12285 {
12288 }
12289 }
12291 /* Update ARGS to restore the substitution from parameter packs to
12292 their argument packs. */
12294 {
12301 else
12302 {
12310 /* Update the corresponding argument. */
12314 else
12316 }
12317 }
12320 {
12323 }
12325 /* If the dependent pack arguments were such that we end up with only a
12326 single pack expansion again, there's no need to keep it in a TREE_VEC. */
12332 }
12334 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
12335 TMPL. We do this using DECL_PARM_INDEX, which should work even with
12336 parameter packs; all parms generated from a function parameter pack will
12337 have the same DECL_PARM_INDEX. */
12339 tree
12341 {
12343 tree patparm;
12346 {
12352 }
12353 else
12354 {
12359 }
12362 }
12364 /* Make an argument pack out of the TREE_VEC VEC. */
12366 static tree
12368 {
12369 tree pack;
12373 else
12374 {
12377 }
12380 }
12382 /* Return an exact copy of template args T that can be modified
12383 independently. */
12385 static tree
12387 {
12395 {
12400 }
12406 }
12408 /* Substitute ARGS into the vector or list of template arguments T. */
12410 static tree
12412 {
12424 {
12426 tree new_arg;
12431 {
12432 /* Substitute into an expansion expression. */
12436 /* Add to the expanded length adjustment the number of
12437 expanded arguments. We subtract one from this
12438 measurement, because the argument pack expression
12439 itself is already counted as 1 in
12440 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
12441 the argument pack is empty. */
12443 }
12445 {
12446 /* Substitute into each of the arguments. */
12455 else
12460 }
12461 else
12470 }
12475 /* Make space for the expanded arguments coming from template
12476 argument packs. */
12478 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
12479 arguments for a member template.
12480 In that case each TREE_VEC in ORIG_T represents a level of template
12481 arguments, and ORIG_T won't carry any non defaulted argument count.
12482 It will rather be the nested TREE_VECs that will carry one.
12483 In other words, ORIG_T carries a non defaulted argument count only
12484 if it doesn't contain any nested TREE_VEC. */
12486 {
12490 }
12492 {
12496 {
12499 /* Now expand the template argument pack "in place". */
12502 }
12503 else
12504 {
12506 out++;
12507 }
12508 }
12511 }
12513 /* Substitute ARGS into one level PARMS of template parameters. */
12515 static tree
12517 {
12524 {
12532 }
12535 }
12537 /* Return the result of substituting ARGS into the template parameters
12538 given by PARMS. If there are m levels of ARGS and m + n levels of
12539 PARMS, then the result will contain n levels of PARMS. For
12540 example, if PARMS is `template <class T> template <class U>
12541 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
12542 result will be `template <int*, double, class V>'. */
12544 static tree
12546 {
12550 /* When substituting into a template, we must set
12551 PROCESSING_TEMPLATE_DECL as the template parameters may be
12552 dependent if they are based on one-another, and the dependency
12553 predicates are short-circuit outside of templates. */
12560 {
12567 }
12572 }
12574 /* Return the result of substituting ARGS into one template parameter
12575 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
12576 parameter and which TREE_PURPOSE is the default argument of the
12577 template parameter. */
12579 static tree
12581 {
12602 }
12604 /* Substitute the ARGS into the indicated aggregate (or enumeration)
12605 type T. If T is not an aggregate or enumeration type, it is
12606 handled as if by tsubst. IN_DECL is as for tsubst. If
12607 ENTERING_SCOPE is nonzero, T is the context for a template which
12608 we are presently tsubst'ing. Return the substituted value. */
12610 static tree
12612 tree args,
12613 tsubst_flags_t complain,
12614 tree in_decl,
12616 {
12621 {
12626 /* Fall through. */
12630 {
12631 tree argvec;
12632 tree context;
12633 tree r;
12637 /* In "sizeof(X<I>)" we need to evaluate "I". */
12643 /* First, determine the context for the type we are looking
12644 up. */
12647 {
12650 /* If context is a nested class inside a class template,
12651 it may still need to be instantiated (c++/33959). */
12653 }
12655 /* Then, figure out what arguments are appropriate for the
12656 type we are trying to find. For example, given:
12658 template <class T> struct S;
12659 template <class T, class U> void f(T, U) { S<U> su; }
12661 and supposing that we are instantiating f<int, double>,
12662 then our ARGS will be {int, double}, but, when looking up
12663 S we only want {double}. */
12668 else
12669 {
12673 }
12679 }
12680 else
12681 /* This is not a template type, so there's nothing to do. */
12686 }
12687 }
12691 /* Substitute into the default argument ARG (a default argument for
12692 FN), which has the indicated TYPE. */
12694 tree
12696 tsubst_flags_t complain)
12697 {
12700 /* This can happen in invalid code. */
12718 /* This default argument came from a template. Instantiate the
12719 default argument here, not in tsubst. In the case of
12720 something like:
12722 template <class T>
12723 struct S {
12724 static T t();
12725 void f(T = t());
12726 };
12728 we must be careful to do name lookup in the scope of S<T>,
12729 rather than in the current class. */
12734 /* The default argument expression may cause implicitly defined
12735 member functions to be synthesized, which will result in garbage
12736 collection. We must treat this situation as if we were within
12737 the body of function so as to avoid collecting live data on the
12738 stack. */
12752 /* Make sure the default argument is reasonable. */
12759 {
12763 }
12766 }
12768 /* Substitute into all the default arguments for FN. */
12770 static void
12772 {
12773 tree arg;
12774 tree tmpl_args;
12778 /* If this function is not yet instantiated, we certainly don't need
12779 its default arguments. */
12782 /* Don't do this again for clones. */
12788 arg;
12794 complain);
12795 }
12797 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12799 static tree
12801 tree lambda_fntype)
12802 {
12807 /* Nobody should be tsubst'ing into non-template functions. */
12811 {
12812 /* If T is not dependent, just return it. */
12816 /* Calculate the most general template of which R is a
12817 specialization. */
12820 /* We're substituting a lambda function under tsubst_lambda_expr but not
12821 directly from it; find the matching function we're already inside.
12822 But don't do this if T is a generic lambda with a single level of
12823 template parms, as in that case we're doing a normal instantiation. */
12829 /* Calculate the complete set of arguments used to
12830 specialize R. */
12832 (DECL_TEMPLATE_RESULT
12838 /* Check to see if we already have this specialization. */
12840 {
12844 }
12846 /* We can see more levels of arguments than parameters if
12847 there was a specialization of a member template, like
12848 this:
12850 template <class T> struct S { template <class U> void f(); }
12851 template <> template <class U> void S<int>::f(U);
12853 Here, we'll be substituting into the specialization,
12854 because that's where we can find the code we actually
12855 want to generate, but we'll have enough arguments for
12856 the most general template.
12858 We also deal with the peculiar case:
12860 template <class T> struct S {
12861 template <class U> friend void f();
12862 };
12863 template <class U> void f() {}
12864 template S<int>;
12865 template void f<double>();
12867 Here, the ARGS for the instantiation of will be {int,
12868 double}. But, we only need as many ARGS as there are
12869 levels of template parameters in CODE_PATTERN. We are
12870 careful not to get fooled into reducing the ARGS in
12871 situations like:
12873 template <class T> struct S { template <class U> void f(U); }
12874 template <class T> template <> void S<T>::f(int) {}
12876 which we can spot because the pattern will be a
12877 specialization in this case. */
12884 }
12885 else
12886 {
12887 /* This special case arises when we have something like this:
12889 template <class T> struct S {
12890 friend void f<int>(int, double);
12891 };
12893 Here, the DECL_TI_TEMPLATE for the friend declaration
12894 will be an IDENTIFIER_NODE. We are being called from
12895 tsubst_friend_function, and we want only to create a
12896 new decl (R) with appropriate types so that we can call
12897 determine_specialization. */
12900 }
12917 /* If we hit excessive deduction depth, the type is bogus even if
12918 it isn't error_mark_node, so don't build a decl. */
12922 /* We do NOT check for matching decls pushed separately at this
12923 point, as they may not represent instantiations of this
12924 template, and in any case are considered separate under the
12925 discrete model. */
12929 /* Clear out the mangled name and RTL for the instantiation. */
12932 /* Leave DECL_INITIAL set on deleted instantiations. */
12937 /* OpenMP UDRs have the only argument a reference to the declared
12938 type. We want to diagnose if the declared type is a reference,
12939 which is invalid, but as references to references are usually
12940 quietly merged, diagnose it here. */
12942 {
12943 tree argtype
12948 "reference type %qT in "
12952 argtype);
12953 }
12956 /* Type-conversion operator. Reconstruct the name, in
12957 case it's the name of one of the template's parameters. */
12967 {
12971 }
12978 /* If this is an instantiation of a function with internal
12979 linkage, we already know what object file linkage will be
12980 assigned to the instantiation. */
12989 /* We'll re-clone as appropriate in instantiate_template. */
12992 /* If we aren't complaining now, return on error before we register
12993 the specialization so that we'll complain eventually. */
12999 /* When instantiating a constrained member, substitute
13000 into the constraints to create a new constraint. */
13003 {
13006 }
13008 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
13009 this in the special friend case mentioned above where
13010 GEN_TMPL is NULL. */
13012 {
13017 tree new_r
13020 /* We instantiated this while substituting into
13021 the type earlier (template/friend54.C). */
13024 /* We're not supposed to instantiate default arguments
13025 until they are called, for a template. But, for a
13026 declaration like:
13028 template <class T> void f ()
13029 { extern void g(int i = T()); }
13031 we should do the substitution when the template is
13032 instantiated. We handle the member function case in
13033 instantiate_class_template since the default arguments
13034 might refer to other members of the class. */
13039 }
13040 else
13043 /* Copy the list of befriending classes. */
13047 {
13051 }
13054 {
13058 /* If this is an instantiation of a member template, clone it.
13059 If it isn't, that'll be handled by
13060 clone_constructors_and_destructors. */
13063 }
13074 /* Possibly limit visibility based on template args. */
13077 {
13081 }
13090 }
13092 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
13094 static tree
13096 tree lambda_fntype)
13097 {
13098 /* We can get here when processing a member function template,
13099 member class template, or template template parameter. */
13102 tree spec;
13103 tree tmpl_args;
13104 tree full_args;
13105 tree r;
13109 {
13110 /* Template template parameter is treated here. */
13114 /* If we get a real template back, return it. This can happen in
13115 the context of most_specialized_partial_spec. */
13118 else
13119 /* The new TEMPLATE_DECL was built in
13120 reduce_template_parm_level. */
13123 }
13126 {
13127 /* We might already have an instance of this template.
13128 The ARGS are for the surrounding class type, so the
13129 full args contain the tsubst'd args for the context,
13130 plus the innermost args from the template decl. */
13134 /* Because this is a template, the arguments will still be
13135 dependent, even after substitution. If
13136 PROCESSING_TEMPLATE_DECL is not set, the dependency
13137 predicates will short-circuit. */
13145 /* If this is a default template template argument,
13146 tsubst might not have changed anything. */
13154 }
13156 /* Make a new template decl. It will be similar to the
13157 original, but will record the current template arguments.
13158 We also create a new function declaration, which is just
13159 like the old one, but points to this new template, rather
13160 than the old one. */
13165 // Build new template info linking to the original template decl.
13167 {
13170 }
13171 else
13174 /* The template parameters for this new template are all the
13175 template parameters for the old template, except the
13176 outermost level of parameters. */
13179 complain);
13183 {
13184 tree new_type;
13192 /* For a partial specialization, we need to keep pointing to
13193 the primary template. */
13199 }
13200 else
13201 {
13202 tree new_decl;
13206 else
13216 {
13219 }
13220 else
13221 {
13224 }
13225 }
13235 /* Record this non-type partial instantiation. */
13241 }
13243 /* True if FN is the op() for a lambda in an uninstantiated template. */
13245 bool
13247 {
13252 }
13254 /* We're instantiating a variable from template function TCTX. Return the
13255 corresponding current enclosing scope. This gets complicated because lambda
13256 functions in templates are regenerated rather than instantiated, but generic
13257 lambda functions are subsequently instantiated. */
13259 static tree
13261 {
13270 {
13283 }
13285 }
13287 /* Substitute the ARGS into the T, which is a _DECL. Return the
13288 result of the substitution. Issue error and warning messages under
13289 control of COMPLAIN. */
13291 static tree
13293 {
13294 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13295 location_t saved_loc;
13300 /* Set the filename and linenumber to improve error-reporting. */
13305 {
13315 {
13323 {
13324 /* If there is a local specialization that isn't a
13325 parameter pack, it means that we're doing a "simple"
13326 substitution from inside tsubst_pack_expansion. Just
13327 return the local specialization (which will be a single
13328 parm). */
13335 /* Expand the TYPE_PACK_EXPANSION that provides the types for
13336 the parameters in this function parameter pack. */
13340 {
13343 /* Zero-length parameter packs are boring. Just substitute
13344 into the chain. */
13348 }
13349 else
13350 {
13351 /* All we did was update the type. Make a note of that. */
13354 }
13355 }
13357 /* Loop through all of the parameters we'll build. When T is
13358 a function parameter pack, LEN is the number of expanded
13359 types in EXPANDED_TYPES; otherwise, LEN is 1. */
13362 {
13369 /* We're on the Ith parameter of the function parameter
13370 pack. */
13371 {
13372 /* Get the Ith type. */
13375 /* Rename the parameter to include the index. */
13378 }
13380 /* We're dealing with a normal parameter. */
13388 {
13391 else
13394 }
13404 /* Keep track of the first new parameter we
13405 generate. That's what will be returned to the
13406 caller. */
13410 /* Build a proper chain of parameters when substituting
13411 into a function parameter pack. */
13414 }
13416 /* If cp_unevaluated_operand is set, we're just looking for a
13417 single dummy parameter, so don't keep going. */
13422 /* FIRST_R contains the start of the chain we've built. */
13424 }
13428 {
13435 {
13436 /* This field is a lambda capture pack. Return a TREE_VEC of
13437 the expanded fields to instantiate_class_template_1. */
13441 {
13444 }
13445 else
13446 {
13447 /* All we did was update the type. Make a note of that. */
13450 }
13451 }
13454 {
13457 {
13461 }
13471 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
13472 number of bits. */
13478 {
13479 /* Set up DECL_TEMPLATE_INFO so that we can get at the
13480 NSDMI in perform_member_init. Still set DECL_INITIAL
13481 so that we know there is one. */
13486 }
13487 /* We don't have to set DECL_CONTEXT here; it is set by
13488 finish_member_declaration. */
13496 }
13500 }
13504 /* We reach here only for member using decls. We also need to check
13505 uses_template_parms because DECL_DEPENDENT_P is not set for a
13506 using-declaration that designates a member of the current
13507 instantiation (c++/53549). */
13510 {
13514 {
13519 {
13523 {
13526 }
13527 else
13528 {
13531 }
13533 }
13534 }
13535 else
13536 {
13542 else
13543 {
13546 }
13547 }
13548 }
13549 else
13550 {
13553 }
13558 {
13561 tree spec;
13563 tree ctx;
13572 {
13573 /* If this is the canonical decl, we don't have to
13574 mess with instantiations, and often we can't (for
13575 typename, template type parms and such). Note that
13576 TYPE_NAME is not correct for the above test if
13577 we've copied the type for a typedef. */
13583 }
13585 /* Check to see if we already have the specialization we
13586 need. */
13589 {
13590 /* T is a static data member or namespace-scope entity.
13591 We have to substitute into namespace-scope variables
13592 (not just variable templates) because of cases like:
13594 template <class T> void f() { extern T t; }
13596 where the entity referenced is not known until
13597 instantiation time. */
13601 {
13603 complain,
13605 /* If CTX is unchanged, then T is in fact the
13606 specialization we want. That situation occurs when
13607 referencing a static data member within in its own
13608 class. We can use pointer equality, rather than
13609 same_type_p, because DECL_CONTEXT is always
13610 canonical... */
13612 /* ... unless T is a member template; in which
13613 case our caller can be willing to create a
13614 specialization of that template represented
13615 by T. */
13619 }
13622 {
13627 argvec = (coerce_innermost_template_parms
13635 }
13636 }
13637 else
13638 {
13639 /* A local variable. */
13641 /* Subsequent calls to pushdecl will fill this in. */
13643 /* Unless this is a reference to a static variable from an
13644 enclosing function, in which case we need to fill it in now. */
13646 {
13650 }
13652 }
13653 /* If we already have the specialization we need, there is
13654 nothing more to do. */
13656 {
13659 }
13661 /* Create a new node for the specialization we need. */
13663 {
13666 else
13674 {
13675 /* Mask off any template args past the variable's context so we
13676 don't replace the auto with an unrelated argument. */
13680 /* This should never happen with the new lambda instantiation
13681 model, but keep the handling just in case. */
13684 }
13686 /* Substituting the type might have recursively instantiated this
13687 same alias (c++/86171). */
13690 {
13693 }
13694 }
13697 {
13703 {
13704 /* It may seem that this case cannot occur, since:
13706 typedef void f();
13707 void g() { f x; }
13709 declares a function, not a variable. However:
13711 typedef void f();
13712 template <typename T> void g() { T t; }
13713 template void g<f>();
13715 is an attempt to declare a variable with function
13716 type. */
13718 /* R is not yet sufficiently initialized, so we
13719 just use its name. */
13722 }
13724 /* Wait until cp_finish_decl to set this again, to handle
13725 circular dependency (template/instantiate6.C). */
13730 {
13735 {
13738 }
13740 }
13744 }
13750 /* Clear out the mangled name and RTL for the instantiation. */
13754 /* The initializer must not be expanded until it is required;
13755 see [temp.inst]. */
13759 {
13765 /* Possibly limit visibility based on template args. */
13768 {
13772 }
13774 }
13777 {
13778 /* A static data member declaration is always marked
13779 external when it is declared in-class, even if an
13780 initializer is present. We mimic the non-template
13781 processing here. */
13789 }
13790 else
13791 {
13796 }
13804 /* Preserve a typedef that names a type. */
13806 {
13810 /* An alias template specialization can be dependent
13811 even if its underlying type is not. */
13813 }
13816 }
13821 }
13822 #undef RETURN
13824 out:
13825 /* Restore the file and line information. */
13829 }
13831 /* Substitute into the ARG_TYPES of a function type.
13832 If END is a TREE_CHAIN, leave it and any following types
13833 un-substituted. */
13835 static tree
13837 tree args,
13838 tree end,
13839 tsubst_flags_t complain,
13840 tree in_decl)
13841 {
13842 tree remaining_arg_types;
13846 tree default_arg;
13857 {
13858 /* For a pack expansion, perform substitution on the
13859 entire expression. Later on, we'll handle the arguments
13860 one-by-one. */
13865 /* So that we'll spin through the parameters, one by one. */
13867 else
13868 {
13869 /* We only partially substituted into the parameter
13870 pack. Our type is TYPE_PACK_EXPANSION. */
13873 }
13874 }
13887 {
13889 {
13893 }
13895 }
13896 /* DR 657. */
13900 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13901 top-level qualifiers as required. */
13904 /* We do not substitute into default arguments here. The standard
13905 mandates that they be instantiated only when needed, which is
13906 done in build_over_call. */
13909 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13910 since the new op() won't have any associated template arguments for us
13911 to refer to later. */
13917 {
13918 /* We've instantiated a template before its default arguments
13919 have been parsed. This can happen for a nested template
13920 class, and is not an error unless we require the default
13921 argument in a call of this function. */
13922 remaining_arg_types =
13925 }
13926 else
13927 remaining_arg_types =
13929 }
13932 }
13934 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13935 *not* handle the exception-specification for FNTYPE, because the
13936 initial substitution of explicitly provided template parameters
13937 during argument deduction forbids substitution into the
13938 exception-specification:
13940 [temp.deduct]
13942 All references in the function type of the function template to the
13943 corresponding template parameters are replaced by the specified tem-
13944 plate argument values. If a substitution in a template parameter or
13945 in the function type of the function template results in an invalid
13946 type, type deduction fails. [Note: The equivalent substitution in
13947 exception specifications is done only when the function is instanti-
13948 ated, at which point a program is ill-formed if the substitution
13949 results in an invalid type.] */
13951 static tree
13953 tree args,
13954 tsubst_flags_t complain,
13955 tree in_decl)
13956 {
13957 tree return_type;
13959 tree fntype;
13961 /* The TYPE_CONTEXT is not used for function/method types. */
13964 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13965 failure. */
13969 {
13970 /* Substitute the argument types. */
13982 {
13983 /* DR 1207: 'this' is in scope in the trailing return type. */
13985 }
13987 /* Substitute the return type. */
13991 {
13994 }
13995 }
13996 else
13997 /* Substitute the return type. */
14002 /* DR 486 clarifies that creation of a function type with an
14003 invalid return type is a deduction failure. */
14006 {
14008 {
14011 else
14013 }
14015 }
14016 /* And DR 657. */
14021 {
14022 /* Substitute the argument types. */
14027 }
14029 /* Construct a new type node and return it. */
14031 {
14034 }
14035 else
14036 {
14038 /* Don't pick up extra function qualifiers from the basetype. */
14041 {
14042 /* [temp.deduct]
14044 Type deduction may fail for any of the following
14045 reasons:
14047 -- Attempting to create "pointer to member of T" when T
14048 is not a class type. */
14051 r);
14053 }
14057 }
14060 /* See comment above. */
14066 }
14068 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
14069 ARGS into that specification, and return the substituted
14070 specification. If there is no specification, return NULL_TREE. */
14072 static tree
14074 tree args,
14075 tsubst_flags_t complain,
14076 tree in_decl,
14078 {
14079 tree specs;
14080 tree new_specs;
14085 {
14086 /* A noexcept-specifier. */
14091 {
14092 /* Defer instantiation of noexcept-specifiers to avoid
14093 excessive instantiations (c++/49107). */
14096 {
14097 /* We already partially instantiated this member template,
14098 so combine the new args with the old. */
14103 }
14104 else
14105 {
14108 }
14109 }
14110 else
14111 new_specs = tsubst_copy_and_build
14115 }
14117 {
14120 else
14122 {
14123 tree spec;
14128 {
14129 /* Expand the pack expansion type. */
14132 in_decl);
14138 else
14139 {
14140 /* We're substituting into a member template, so
14141 we got a TYPE_PACK_EXPANSION back. Add that
14142 expansion and move on. */
14146 expanded_specs,
14147 complain);
14150 }
14151 }
14154 {
14157 else
14162 complain);
14163 }
14166 }
14167 }
14169 }
14171 /* Take the tree structure T and replace template parameters used
14172 therein with the argument vector ARGS. IN_DECL is an associated
14173 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
14174 Issue error and warning messages under control of COMPLAIN. Note
14175 that we must be relatively non-tolerant of extensions here, in
14176 order to preserve conformance; if we allow substitutions that
14177 should not be allowed, we may allow argument deductions that should
14178 not succeed, and therefore report ambiguous overload situations
14179 where there are none. In theory, we could allow the substitution,
14180 but indicate that it should have failed, and allow our caller to
14181 make sure that the right thing happens, but we don't try to do this
14182 yet.
14184 This function is used for dealing with types, decls and the like;
14185 for expressions, use tsubst_expr or tsubst_copy. */
14187 tree
14189 {
14212 else
14217 /* Reuse typedefs. We need to do this to handle dependent attributes,
14218 such as attribute aligned. */
14221 {
14225 {
14226 /* DECL represents an alias template and we want to
14227 instantiate it. */
14231 }
14235 {
14239 }
14244 else
14245 /* The typedef is from a non-template context. */
14249 {
14251 r = cp_build_qualified_type_real
14255 }
14256 else
14257 {
14258 /* We don't have an instantiation yet, so drop the typedef. */
14263 }
14264 }
14281 {
14307 {
14313 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
14314 needed. */
14320 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
14321 with TREE_SIDE_EFFECTS that indicates this is not an integral
14322 constant expression. */
14325 {
14328 }
14331 }
14337 {
14343 /* Early in template argument deduction substitution, we don't
14344 want to reduce the level of 'auto', or it will be confused
14345 with a normal template parm in subsequent deduction. */
14357 {
14360 /* See through ARGUMENT_PACK_SELECT arguments. */
14363 }
14368 {
14370 /* If ARG is an argument pack, we don't actually want to
14371 perform a substitution here, because substitutions
14372 for argument packs are only done
14373 element-by-element. We can get to this point when
14374 substituting the type of a non-type template
14375 parameter pack, when that type actually contains
14376 template parameter packs from an outer template, e.g.,
14378 template<typename... Types> struct A {
14379 template<Types... Values> struct B { };
14380 }; */
14384 {
14390 return cp_build_qualified_type_real
14392 }
14394 {
14395 /* We are processing a type constructed from a
14396 template template parameter. */
14407 /* Consider this code:
14409 template <template <class> class Template>
14410 struct Internal {
14411 template <class Arg> using Bind = Template<Arg>;
14412 };
14414 template <template <class> class Template, class Arg>
14415 using Instantiate = Template<Arg>; //#0
14417 template <template <class> class Template,
14418 class Argument>
14419 using Bind =
14420 Instantiate<Internal<Template>::template Bind,
14421 Argument>; //#1
14423 When #1 is parsed, the
14424 BOUND_TEMPLATE_TEMPLATE_PARM representing the
14425 parameter `Template' in #0 matches the
14426 UNBOUND_CLASS_TEMPLATE representing the argument
14427 `Internal<Template>::template Bind'; We then want
14428 to assemble the type `Bind<Argument>' that can't
14429 be fully created right now, because
14430 `Internal<Template>' not being complete, the Bind
14431 template cannot be looked up in that context. So
14432 we need to "store" `Bind<Argument>' for later
14433 when the context of Bind becomes complete. Let's
14434 store that in a TYPENAME_TYPE. */
14438 argvec),
14439 typename_type,
14440 complain);
14442 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
14443 are resolving nested-types in the signature of a
14444 member function templates. Otherwise ARG is a
14445 TEMPLATE_DECL and is the real template to be
14446 instantiated. */
14454 complain);
14455 return cp_build_qualified_type_real
14457 }
14460 else
14461 /* TEMPLATE_PARM_INDEX. */
14463 }
14466 /* This can happen during the attempted tsubst'ing in
14467 unify. This means that we don't yet have any information
14468 about the template parameter in question. */
14471 /* If we get here, we must have been looking at a parm for a
14472 more deeply nested template. Make a new version of this
14473 template parameter, but with a lower level. */
14475 {
14480 {
14482 r = cp_build_qualified_type_real
14486 }
14493 /* Break infinite recursion when substituting the constraints
14502 /* Cache the simple case of lowering a type parameter. */
14504 else
14505 {
14516 {
14517 /* Propagate constraints on placeholders. */
14522 {
14525 }
14526 }
14529 /* We have reduced the level of the template
14530 template parameter, but not the levels of its
14531 template parameters, so canonical_type_parameter
14532 will not be able to find the canonical template
14533 template parameter for this level. Thus, we
14534 require structural equality checking to compare
14535 TEMPLATE_TEMPLATE_PARMs. */
14539 else
14543 {
14545 /* We might need to substitute into the types of non-type
14546 template parameters. */
14558 }
14559 }
14563 /* OK, now substitute the type of the non-type parameter. We
14564 couldn't do it earlier because it might be an auto parameter,
14565 and we wouldn't need to if we had an argument. */
14574 }
14577 }
14580 {
14588 {
14592 }
14595 {
14599 }
14602 {
14606 }
14612 }
14615 /* We should never be tsubsting a binfo. */
14619 /* A vector of template arguments. */
14625 {
14629 /* [temp.deduct]
14631 Type deduction may fail for any of the following
14632 reasons:
14634 -- Attempting to create a pointer to reference type.
14635 -- Attempting to create a reference to a reference type or
14636 a reference to void.
14638 Core issue 106 says that creating a reference to a reference
14639 during instantiation is no longer a cause for failure. We
14640 only enforce this check in strict C++98 mode. */
14644 {
14647 /* We keep track of the last time we issued this error
14648 message to avoid spewing a ton of messages during a
14649 single bad template instantiation. */
14652 {
14657 else
14660 }
14663 }
14667 {
14669 {
14672 type);
14673 else
14675 type);
14676 }
14678 }
14680 {
14684 }
14686 /* In C++0x, during template argument substitution, when there is an
14687 attempt to create a reference to a reference type, reference
14688 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14690 "If a template-argument for a template-parameter T names a type
14691 that is a reference to a type A, an attempt to create the type
14692 'lvalue reference to cv T' creates the type 'lvalue reference to
14693 A,' while an attempt to create the type type rvalue reference to
14694 cv T' creates the type T"
14695 */
14696 r = cp_build_reference_type
14699 else
14704 /* Will this ever be needed for TYPE_..._TO values? */
14708 }
14710 {
14713 {
14714 /* [temp.deduct]
14716 Type deduction may fail for any of the following
14717 reasons:
14719 -- Attempting to create "pointer to member of T" when T
14720 is not a class type. */
14724 }
14726 {
14730 }
14732 {
14736 }
14739 {
14740 /* The type of the implicit object parameter gets its
14741 cv-qualifiers from the FUNCTION_TYPE. */
14742 tree memptr;
14743 tree method_type
14748 complain);
14749 }
14750 else
14753 complain);
14754 }
14757 {
14758 tree fntype;
14759 tree specs;
14764 /* Substitute the exception specification. */
14772 }
14774 {
14779 /* As an optimization, we avoid regenerating the array type if
14780 it will obviously be the same as T. */
14784 /* These checks should match the ones in create_array_type_for_decl.
14786 [temp.deduct]
14788 The deduction may fail for any of the following reasons:
14790 -- Attempting to create an array with an element type that
14791 is void, a function type, or a reference type, or [DR337]
14792 an abstract class type. */
14798 {
14802 }
14814 {
14817 }
14820 }
14823 {
14835 {
14839 }
14841 {
14842 /* Normally, make_typename_type does not require that the CTX
14843 have complete type in order to allow things like:
14845 template <class T> struct S { typename S<T>::X Y; };
14847 But, such constructs have already been resolved by this
14848 point, so here CTX really should have complete type, unless
14849 it's a partial instantiation. */
14852 {
14856 }
14857 }
14864 {
14867 }
14870 {
14872 {
14876 else
14878 }
14880 {
14884 else
14886 }
14887 }
14889 return cp_build_qualified_type_real
14891 }
14894 {
14906 }
14909 {
14910 tree type;
14926 complain);
14927 }
14930 {
14931 tree type;
14942 {
14944 {
14948 }
14951 }
14962 else
14963 {
14967 /* In a template ~id could be either a complement expression
14968 or an unqualified-id naming a destructor; if instantiating
14969 it produces an expression, it's not an id-expression or
14970 member access. */
14973 }
14978 }
14981 {
14985 }
14989 {
14990 tree r;
14994 else
15002 }
15017 /* We should use one of the expression tsubsts for these codes. */
15023 }
15024 }
15026 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
15027 expression on the left-hand side of the "." or "->" operator. We
15028 only do the lookup if we had a dependent BASELINK. Otherwise we
15029 adjust it onto the instantiated heirarchy. */
15031 static tree
15034 {
15046 {
15053 }
15060 {
15066 /* Treat as-if non-dependent below. */
15071 {
15077 }
15081 }
15082 else
15083 /* We're going to overwrite pieces below, make a duplicate. */
15086 /* If lookup found a single function, mark it as used at this point.
15087 (If lookup found multiple functions the one selected later by
15088 overload resolution will be marked as used at that point.) */
15090 {
15096 /* We might have instantiated an auto function. */
15098 }
15101 {
15102 /* Add back the template arguments, if present. */
15107 /* Update the conversion operator type. */
15109 }
15115 {
15117 qualifying_scope,
15118 object_type);
15120 /* We need to call adjust_result_of_qualified_name_lookup in case the
15121 destructor names a base class, but we unset BASELINK_QUALIFIED_P
15122 so that we still get virtual function binding. */
15124 }
15127 }
15129 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
15130 true if the qualified-id will be a postfix-expression in-and-of
15131 itself; false if more of the postfix-expression follows the
15132 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
15133 of "&". */
15135 static tree
15139 {
15140 tree expr;
15141 tree scope;
15142 tree name;
15144 tree template_args;
15149 /* Figure out what name to look up. */
15152 {
15162 }
15163 else
15164 {
15167 }
15169 /* Substitute into the qualifying scope. When there are no ARGS, we
15170 are just trying to simplify a non-dependent expression. In that
15171 case the qualifying scope may be dependent, and, in any case,
15172 substituting will not help. */
15175 {
15178 }
15179 else
15183 {
15190 }
15193 {
15195 {
15196 /* A BIT_NOT_EXPR is used to represent a destructor. */
15198 {
15202 }
15203 else
15206 }
15207 else
15211 {
15213 {
15217 }
15219 }
15220 }
15223 {
15225 scope);
15226 /* Remember that there was a reference to this entity. */
15229 }
15232 {
15238 }
15241 {
15242 /* We may be repeating a check already done during parsing, but
15243 if it was well-formed and passed then, it will pass again
15244 now, and if it didn't, we wouldn't have got here. The case
15245 we want to catch is when we couldn't tell then, and can now,
15246 namely when templ prior to substitution was an
15247 identifier. */
15253 complain);
15254 else
15256 }
15262 {
15263 expr = (adjust_result_of_qualified_name_lookup
15265 expr = (finish_qualified_id_expr
15269 }
15271 /* Expressions do not generally have reference type. */
15273 /* However, if we're about to form a pointer-to-member, we just
15274 want the referenced member referenced. */
15282 }
15284 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
15285 initializer, DECL is the substituted VAR_DECL. Other arguments are as
15286 for tsubst. */
15288 static tree
15291 {
15298 {
15299 /* If we had an initializer but it
15300 instantiated to nothing,
15301 value-initialize the object. This will
15302 only occur when the initializer was a
15303 pack expansion where the parameter packs
15304 used in that expansion were of length
15305 zero. */
15307 complain);
15312 }
15315 }
15317 /* Like tsubst, but deals with expressions. This function just replaces
15318 template parms; to finish processing the resultant expression, use
15319 tsubst_copy_and_build or tsubst_expr. */
15321 static tree
15323 {
15325 tree r;
15333 {
15338 {
15339 /* We get here for a use of 'this' in an NSDMI. */
15343 /* This can happen for a parameter name used later in a function
15344 declaration (such as in a late-specified return type). Just
15345 make a dummy decl, since it's only used for its type. */
15348 /* Give it the template pattern as its context; its true context
15349 hasn't been instantiated yet and this is good enough for
15350 mangling. */
15352 }
15361 {
15362 tree enum_type;
15363 tree v;
15367 /* There is no need to substitute into namespace-scope
15368 enumerators. */
15371 /* If ARGS is NULL, then T is known to be non-dependent. */
15375 /* Unfortunately, we cannot just call lookup_name here.
15376 Consider:
15378 template <int I> int f() {
15379 enum E { a = I };
15380 struct S { void g() { E e = a; } };
15381 };
15383 When we instantiate f<7>::S::g(), say, lookup_name is not
15384 clever enough to find f<7>::a. */
15385 enum_type
15395 /* We didn't find the name. That should never happen; if
15396 name-lookup found it during preliminary parsing, we
15397 should find it again here during instantiation. */
15399 }
15404 {
15405 tree ctx;
15410 {
15413 {
15417 }
15419 }
15420 }
15430 {
15433 {
15434 /* First try name lookup to find the instantiation. */
15437 {
15438 /* Make sure that the one we found is the one we want. */
15442 }
15446 else
15447 {
15448 /* This can happen for a variable used in a
15449 late-specified return type of a local lambda, or for a
15450 local static or constant. Building a new VAR_DECL
15451 should be OK in all those cases. */
15454 /* Avoid infinite recursion (79640). */
15457 {
15458 /* We can't call cp_finish_decl, so handle the
15459 initializer by hand. */
15474 }
15481 }
15482 /* Remember this for subsequent uses. */
15485 }
15488 }
15489 else
15499 /* An OVERLOAD will always be a non-dependent overload set; an
15500 overload set from function scope will just be represented with an
15501 IDENTIFIER_NODE, and from class scope with a BASELINK. */
15503 /* We must have marked any lookups as persistent. */
15519 {
15520 /* Template template argument like the following example need
15521 special treatment:
15523 template <template <class> class TT> struct C {};
15524 template <class T> struct D {
15525 template <class U> struct E {};
15526 C<E> c; // #1
15527 };
15528 D<int> d; // #2
15530 We are processing the template argument `E' in #1 for
15531 the template instantiation #2. Originally, `E' is a
15532 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
15533 have to substitute this with one having context `D<int>'. */
15537 {
15538 /* When rewriting a constructor into a deduction guide, a
15539 non-dependent name can become dependent, so memtmpl<args>
15540 becomes context::template memtmpl<args>. */
15544 }
15546 }
15547 else
15548 /* Ordinary template template argument. */
15553 {
15554 /* Handle location wrappers by substituting the wrapped node
15555 first, *then* reusing the resulting type. Doing the type
15556 first ensures that we handle template parameters and
15557 parameter pack expansions. */
15561 }
15571 {
15575 }
15580 {
15589 /* We only want to compute the number of arguments. */
15592 else
15599 {
15601 /* Set TREE_USED for the benefit of -Wunused. */
15605 }
15613 {
15618 else
15625 else
15628 }
15629 else
15631 }
15633 {
15641 }
15642 /* Fall through */
15658 {
15665 }
15668 {
15669 tree object;
15670 tree name;
15675 {
15679 }
15682 {
15692 }
15697 in_decl);
15698 else
15701 }
15739 {
15743 }
15746 {
15751 }
15754 {
15758 }
15761 {
15769 }
15775 {
15782 }
15785 {
15792 }
15795 {
15802 }
15805 {
15806 /* Substituted template arguments */
15815 }
15818 {
15838 }
15863 /* Fall through. */
15866 {
15869 }
15870 else
15874 /* This is handled by tsubst_copy_and_build. */
15878 {
15882 }
15885 /* We shouldn't have built any of these during initial template
15886 generation. Instead, they should be built during instantiation
15887 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15891 {
15901 }
15919 {
15920 /* Instantiate any typedefs in the type. */
15925 }
15928 /* These can sometimes show up in a partial instantiation, but never
15929 involve template parms. */
15945 /* ??? There's no point in copying it for now, but maybe some
15946 day it will contain more information, such as a pointer back
15947 to the containing function, inlined copy or so. */
15951 /* We shouldn't get here, but keep going if !flag_checking. */
15955 }
15956 }
15958 /* Helper function for tsubst_omp_clauses, used for instantiation of
15959 OMP_CLAUSE_DECL of clauses. */
15961 static tree
15963 tree in_decl)
15964 {
15968 /* Handle an OpenMP array section represented as a TREE_LIST (or
15969 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15970 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15971 TREE_LIST. We can handle it exactly the same as an array section
15972 (purpose, value, and a chain), even though the nomenclature
15973 (low_bound, length, etc) is different. */
15975 {
15976 tree low_bound
15982 in_decl);
15991 }
15994 /* Undo convert_from_reference tsubst_expr could have called. */
16000 }
16002 /* Like tsubst_copy, but specifically for OpenMP clauses. */
16004 static tree
16007 {
16012 {
16018 {
16021 {
16027 }
16028 /* FALLTHRU */
16043 in_decl);
16075 {
16078 {
16085 }
16086 else
16088 }
16091 in_decl);
16097 in_decl);
16105 in_decl);
16107 {
16110 }
16115 else
16118 in_decl,
16144 }
16147 {
16157 /* tsubst_expr on SCOPE_REF results in returning
16158 finish_non_static_data_member result. Undo that here. */
16162 {
16167 {
16171 CASE_CONVERT:
16180 /* FALLTHRU */
16184 }
16185 }
16191 {
16194 {
16197 }
16198 }
16202 }
16203 }
16207 {
16212 {
16215 }
16216 }
16218 }
16220 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
16222 static tree
16224 tree in_decl)
16225 {
16226 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
16246 {
16249 else
16250 {
16254 }
16255 }
16260 #undef RECUR
16261 }
16263 /* Used to temporarily communicate the list of #pragma omp parallel
16264 clauses to #pragma omp for instantiation if they are combined
16265 together. */
16269 /* Substitute one OMP_FOR iterator. */
16271 static void
16276 {
16277 #define RECUR(NODE) \
16278 tsubst_expr ((NODE), args, complain, in_decl, \
16279 integral_constant_expression_p)
16286 {
16292 else
16294 }
16300 {
16301 /* We need to jump through some hoops to handle declarations in the
16302 init-statement, since we might need to handle auto deduction,
16303 but we need to keep control of initialization. */
16307 }
16308 else
16309 {
16311 {
16314 {
16318 {
16322 CASE_CONVERT:
16330 {
16333 }
16334 /* FALLTHRU */
16338 }
16339 }
16340 }
16341 else
16343 }
16354 {
16356 {
16357 /* Declare the variable, but don't let that initialize it. */
16362 }
16367 {
16372 }
16373 else
16380 }
16383 {
16384 /* Declare and initialize the variable. */
16387 }
16389 {
16393 {
16395 {
16401 {
16404 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
16409 }
16412 {
16414 decl);
16416 }
16419 {
16421 decl);
16423 }
16424 else
16426 }
16429 }
16431 {
16436 {
16439 }
16440 }
16441 }
16444 {
16448 }
16449 else
16453 {
16464 {
16472 }
16473 else
16479 {
16485 }
16489 {
16497 }
16498 else
16504 }
16510 #undef RECUR
16511 }
16513 /* Helper function of tsubst_expr, find OMP_TEAMS inside
16514 of OMP_TARGET's body. */
16516 static tree
16518 {
16521 {
16530 }
16532 }
16534 /* Helper function for tsubst_expr. For decomposition declaration
16535 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
16536 also the corresponding decls representing the identifiers
16537 of the decomposition declaration. Return DECL if successful
16538 or error_mark_node otherwise, set *FIRST to the first decl
16539 in the list chained through DECL_CHAIN and *CNT to the number
16540 of such decls. */
16542 static tree
16546 {
16551 decl2
16556 {
16558 {
16561 }
16573 else
16574 {
16578 }
16585 {
16588 }
16589 else
16591 }
16594 }
16596 /* Like tsubst_copy for expressions, etc. but also does semantic
16597 processing. */
16599 tree
16602 {
16603 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
16604 #define RECUR(NODE) \
16605 tsubst_expr ((NODE), args, complain, in_decl, \
16606 integral_constant_expression_p)
16609 tree r;
16610 location_t loc;
16622 {
16624 {
16625 tree_stmt_iterator i;
16629 }
16644 else
16654 {
16656 tree init;
16662 {
16672 else
16674 }
16677 {
16678 /* We're in tsubst_lambda_expr, we've already inserted a new
16679 capture proxy, so look it up and register it. */
16680 tree inst;
16682 {
16683 inst = (retrieve_local_specialization
16686 }
16687 else
16688 {
16692 }
16695 }
16698 /* Don't copy the old closure; we'll create a new one in
16699 tsubst_lambda_expr. */
16701 else
16702 {
16706 {
16707 /* By marking the declaration as instantiated, we avoid
16708 trying to instantiate it. Since instantiate_decl can't
16709 handle local variables, and since we've already done
16710 all that needs to be done, that's the right thing to
16711 do. */
16716 /* Anonymous aggregates are a special case. */
16719 {
16722 {
16726 }
16728 }
16734 {
16739 }
16740 else
16741 {
16756 {
16757 /* For __PRETTY_FUNCTION__ we have to adjust the
16758 initializer. */
16762 }
16763 else
16767 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16777 }
16778 }
16779 }
16782 }
16792 {
16796 }
16801 {
16802 /* Construct another range_for, if this is not a final
16803 substitution (for inside inside a generic lambda of a
16804 template). Otherwise convert to a regular for. */
16806 stmt = (processing_template_decl
16822 {
16826 }
16827 else
16828 {
16834 }
16840 }
16847 {
16851 }
16857 {
16861 }
16876 {
16877 /* We're partially instantiating a generic lambda, but the condition
16878 of the constexpr if is still dependent. Don't substitute into the
16879 branches now, just remember the template arguments. */
16887 }
16890 else
16891 {
16899 }
16905 {
16915 }
16923 else
16931 else
16952 {
16959 }
16963 {
16965 tree label;
16972 }
16978 /* Computed goto's must be tsubst'd into. On the other hand,
16979 non-computed gotos must not be; the identifier in question
16980 will have no binding. */
16982 else
16988 {
17004 }
17009 {
17014 }
17015 else
17016 {
17021 else
17028 else
17034 else
17036 }
17040 {
17044 {
17046 /* Prevent instantiate_decl from trying to instantiate
17047 this variable. We've already done all that needs to be
17048 done. */
17051 }
17056 }
17062 {
17063 /* Local classes are not independent templates; they are
17064 instantiated along with their containing function. And this
17065 way we don't have to deal with pushing out of one local class
17066 to instantiate a member of another local class. */
17067 /* Closures are handled by the LAMBDA_EXPR. */
17077 }
17081 {
17082 tree condition;
17085 condition =
17087 args,
17096 }
17102 in_decl);
17137 {
17150 in_decl);
17152 {
17159 }
17171 integral_constant_expression_p);
17182 else
17183 {
17191 }
17195 }
17200 /* FALLTHRU */
17207 in_decl);
17224 in_decl);
17235 {
17238 {
17239 /* For combined target teams, ensure the num_teams and
17240 thread_limit clause expressions are evaluated on the host,
17241 before entering the target construct. */
17242 tree c;
17248 {
17257 OMP_CLAUSE_FIRSTPRIVATE);
17261 }
17262 }
17263 }
17323 {
17328 {
17331 }
17337 }
17338 else
17339 {
17346 {
17349 }
17352 {
17357 {
17360 }
17366 }
17367 else
17368 {
17372 }
17375 }
17379 {
17385 {
17389 {
17394 }
17398 }
17399 else
17400 {
17405 }
17406 }
17410 {
17414 }
17427 /* If the first operand was a statement, we're done with it. */
17431 complain));
17445 integral_constant_expression_p));
17446 }
17449 out:
17452 #undef RECUR
17453 #undef RETURN
17454 }
17456 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
17457 function. For description of the body see comment above
17458 cp_parser_omp_declare_reduction_exprs. */
17460 static void
17462 {
17468 tree_stmt_iterator tsi;
17479 {
17498 }
17500 {
17520 }
17521 }
17523 /* T is a postfix-expression that is not being used in a function
17524 call. Return the substituted version of T. */
17526 static tree
17528 tsubst_flags_t complain,
17529 tree in_decl)
17530 {
17534 else
17540 }
17542 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
17543 instantiation context. Instantiating a pack expansion containing a lambda
17544 might result in multiple lambdas all based on the same lambda in the
17545 template. */
17547 tree
17549 {
17562 /* A lambda in a default argument outside a class gets no
17563 LAMBDA_EXPR_EXTRA_SCOPE, as specified by the ABI. But
17564 tsubst_default_argument calls start_lambda_scope, so we need to
17565 specifically ignore it here, and use the global scope. */
17567 else
17575 {
17587 else
17592 {
17601 }
17602 else
17603 {
17609 }
17610 }
17616 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17634 else
17635 {
17636 /* Fix the type of 'this'. */
17642 {
17646 }
17647 else
17648 {
17652 }
17654 /* Let finish_function set this. */
17660 else
17661 /* Still increment function_depth so that we don't GC in the
17662 middle of an expression. */
17672 {
17673 /* We might not partially instantiate some parts of the function, so
17674 copy these flags from the original template. */
17680 }
17689 else
17692 /* The capture list was built up in reverse order; fix that now. */
17699 }
17706 }
17708 /* Like tsubst but deals with expressions and performs semantic
17709 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
17711 tree
17713 tree args,
17714 tsubst_flags_t complain,
17715 tree in_decl,
17718 {
17719 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17720 #define RECUR(NODE) \
17721 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17723 integral_constant_expression_p)
17726 location_t loc;
17735 /* N3276 decltype magic only applies to calls at the top level or on the
17736 right side of a comma. */
17741 {
17744 /* Fall through. */
17746 {
17747 tree decl;
17748 cp_id_kind idk;
17753 {
17756 }
17758 /* Look up the name. */
17761 /* By convention, expressions use ERROR_MARK_NODE to indicate
17762 failure, not NULL_TREE. */
17768 integral_constant_expression_p,
17776 input_location);
17780 {
17784 }
17786 }
17789 {
17790 tree object;
17800 {
17805 }
17811 {
17814 }
17815 else
17822 else
17824 }
17827 {
17831 {
17832 /* A type conversion to reference type will be enclosed in
17833 such an indirect ref, but the substitution of the cast
17834 will have also added such an indirect ref. */
17836 }
17837 else
17845 }
17848 {
17852 }
17855 {
17859 {
17864 }
17866 /* We'll pass this to convert_nontype_argument again, we don't need
17867 to actually perform any conversion here. */
17873 flags));
17874 }
17877 {
17883 }
17890 {
17891 tree type;
17897 {
17902 }
17909 {
17927 }
17930 }
17963 else
17965 in_decl);
18000 {
18007 tree r = build_x_binary_op
18009 op0,
18011 ? ERROR_MARK
18013 op1,
18015 ? ERROR_MARK
18023 }
18026 {
18030 }
18046 /* Fall through */
18049 {
18050 tree r;
18058 {
18059 /* When there are no ARGS, we are trying to evaluate a
18060 non-dependent expression from the parser. Trying to do
18061 the substitutions may not work. */
18064 }
18065 else
18066 {
18071 else
18074 /*integral_constant_expression_p=*/
18078 }
18082 else
18086 {
18088 {
18090 {
18094 }
18095 else
18099 }
18101 }
18103 }
18106 {
18116 }
18132 {
18136 tree r = build_x_modify_expr
18139 /* TREE_NO_WARNING must be set if either the expression was
18140 parenthesized or it uses an operator such as >>= rather
18141 than plain assignment. In the former case, it was already
18142 set and must be copied. In the latter case,
18143 build_x_modify_expr sets it and it must not be reset
18144 here. */
18149 }
18154 /* Remember that there was a reference to this entity. */
18161 {
18166 tree ret;
18170 else
18171 {
18175 }
18177 /* If there was an initializer in the original tree, but it
18178 instantiated to an empty list, then we should pass a
18179 non-NULL empty vector to tell build_new that it was an
18180 empty initializer() rather than no initializer. This can
18181 only happen when the initializer is a pack expansion whose
18182 parameter packs are of length zero. */
18185 else
18186 {
18190 else
18191 {
18194 }
18195 }
18197 /* Avoid passing an enclosing decl to valid_array_size_p. */
18204 complain);
18212 }
18215 {
18221 complain));
18222 }
18225 {
18229 integral_constant_expression_p);
18231 op0,
18234 }
18237 {
18238 tree function;
18243 tree ret;
18246 /* Internal function with no arguments. */
18250 /* When we parsed the expression, we determined whether or
18251 not Koenig lookup should be performed. */
18254 {
18257 }
18259 {
18264 }
18266 {
18267 /* Do nothing; calling tsubst_copy_and_build on an identifier
18268 would incorrectly perform unqualified lookup again.
18270 Note that we can also have an IDENTIFIER_NODE if the earlier
18271 unqualified lookup found a member function; in that case
18272 koenig_p will be false and we do want to do the lookup
18273 again to find the instantiated member function.
18275 FIXME but doing that causes c++/15272, so we need to stop
18276 using IDENTIFIER_NODE in that situation. */
18278 }
18279 else
18280 {
18282 {
18288 }
18289 else
18294 /* Avoid error about taking the address of a constructor. */
18298 in_decl,
18300 integral_constant_expression_p);
18304 }
18309 {
18314 else
18315 {
18316 /* Expand the pack expansion and push each entry onto
18317 CALL_ARGS. */
18320 {
18325 {
18330 }
18331 }
18332 else
18333 {
18334 /* A partial substitution. Add one entry. */
18336 }
18337 }
18338 }
18340 /* We do not perform argument-dependent lookup if normal
18341 lookup finds a non-function, in accordance with the
18342 expected resolution of DR 218. */
18345 /* If lookup found a member function, the Koenig lookup is
18346 not appropriate, even if an unqualified-name was used
18347 to denote the function. */
18350 /* Only do this when substitution turns a dependent call
18351 into a non-dependent call. */
18359 {
18361 {
18362 /* For backwards compatibility and good diagnostics, try
18363 the unqualified lookup again if we aren't in SFINAE
18364 context. */
18365 tree unq = (tsubst_copy_and_build
18367 integral_constant_expression_p));
18369 {
18372 }
18375 {
18376 /* In a lambda fn, we have to be careful to not
18377 introduce new this captures. Legacy code can't
18378 be using lambdas anyway, so it's ok to be
18379 stricter. */
18384 "and no declarations were found by "
18385 "argument-dependent lookup at the point "
18392 else
18396 {
18407 {
18409 input_location);
18411 "declarations in dependent base %qT are "
18417 else
18421 }
18422 else
18424 "%qD declared here, later in the "
18427 {
18430 }
18431 }
18434 }
18435 }
18437 {
18442 }
18443 }
18445 /* Remember that there was a reference to this entity. */
18449 {
18452 }
18454 /* Put back tf_decltype for the actual call. */
18459 {
18463 {
18465 "wrong number of arguments to "
18468 }
18469 else
18471 input_location),
18476 /* Unsupported internal function with arguments. */
18478 }
18483 complain);
18485 {
18500 complain);
18501 else
18502 ret = (build_new_method_call
18507 complain));
18508 }
18509 else
18512 koenig_p,
18513 complain);
18518 {
18524 {
18530 {
18533 else
18535 /* The thunk location is not interesting. */
18537 }
18538 }
18539 }
18542 }
18545 {
18552 {
18554 {
18559 }
18560 else
18561 {
18566 }
18568 }
18569 else
18570 {
18573 }
18578 }
18581 {
18586 input_location));
18587 }
18590 {
18598 {
18599 /* We have pack expansions, so expand those and
18600 create a new list out of it. */
18603 tree chain;
18606 /* Expand the argument expressions. */
18614 /* Build the rest of the list. */
18619 /* Determine the number of arguments. */
18621 {
18624 }
18627 else
18628 {
18629 /* Since we only performed a partial substitution into
18630 the argument pack, we only RETURN (a single list
18631 node. */
18638 }
18640 /* Convert the argument vectors into a TREE_LIST */
18643 {
18644 /* Grab the Ith values. */
18645 i--;
18648 value
18652 /* Build the list (backwards). */
18654 }
18657 }
18673 }
18676 {
18677 tree object;
18678 tree object_type;
18679 tree member;
18680 tree r;
18684 /* Remember that there was a reference to this entity. */
18695 else
18701 {
18706 }
18710 {
18712 {
18717 {
18720 }
18722 {
18727 }
18728 }
18729 }
18732 {
18733 /* Lookup the template functions now that we know what the
18734 scope is. */
18742 {
18745 args);
18746 member = (adjust_result_of_qualified_name_lookup
18748 object_type));
18749 }
18750 else
18751 {
18753 input_location);
18755 }
18756 }
18760 {
18762 {
18766 else
18769 }
18771 }
18775 complain);
18779 }
18786 {
18794 tree r;
18799 /* We do not want to process the index of aggregate
18800 initializers as they are identifier nodes which will be
18801 looked up by digest_init. */
18807 {
18809 /* An identifier index is looked up in the type
18810 being initialized, not the current scope. */
18815 {
18816 /* Substitute into the pack expansion. */
18818 in_decl);
18822 ;
18824 /* Just move the argument into place. */
18826 else
18827 {
18828 /* Update the length of the final CONSTRUCTOR
18829 arguments vector, and note that we will need to
18830 copy.*/
18833 }
18834 }
18835 else
18837 }
18840 {
18845 {
18847 {
18852 }
18853 else
18855 }
18856 }
18862 {
18867 }
18871 }
18874 {
18877 {
18880 }
18881 else
18882 {
18885 }
18886 }
18891 /* Fall through */
18894 {
18896 /* ??? We're doing a subset of finish_id_expression here. */
18898 && !processing_template_decl
18899 && !cp_unevaluated_operand
18902 {
18904 /* Replace an evaluated use of the thread_local variable with
18905 a call to its wrapper. */
18907 }
18912 /* If the original type was a reference, we'll be wrapped in
18913 the appropriate INDIRECT_REF. */
18916 }
18919 {
18923 }
18926 {
18927 tree object_ptr
18934 }
18941 {
18952 }
18955 {
18961 integral_constant_expression_p);
18965 /* If the resulting list of expression statement is empty,
18966 fold it further into void_node. */
18971 }
18974 {
18978 }
18981 /* We can get here for a constant initializer of non-dependent type.
18982 FIXME stop folding in cp_parser_initializer_clause. */
18983 {
18985 complain);
18987 }
18991 integral_constant_expression_p));
18997 {
19002 complain));
19003 }
19010 /* We should only see these for location wrapper nodes, or within
19011 instantiate_non_dependent_expr (when args is NULL_TREE). */
19016 /* fallthrough. */
19019 /* Handle Objective-C++ constructs, if appropriate. */
19020 {
19021 tree subst
19026 }
19028 }
19030 #undef RECUR
19031 #undef RETURN
19032 out:
19035 }
19037 /* Verify that the instantiated ARGS are valid. For type arguments,
19038 make sure that the type's linkage is ok. For non-type arguments,
19039 make sure they are constants if they are integral or enumerations.
19040 Emit an error under control of COMPLAIN, and return TRUE on error. */
19042 static bool
19044 {
19048 {
19058 }
19060 {
19061 /* [basic.link]: A name with no linkage (notably, the name
19062 of a class or enumeration declared in a local scope)
19063 shall not be used to declare an entity with linkage.
19064 This implies that names with no linkage cannot be used as
19065 template arguments
19067 DR 757 relaxes this restriction for C++0x. */
19072 {
19073 /* DR 488 makes use of a type with no linkage cause
19074 type deduction to fail. */
19076 {
19079 else
19082 }
19084 }
19085 /* In order to avoid all sorts of complications, we do not
19086 allow variably-modified types as template arguments. */
19088 {
19092 }
19093 }
19094 /* Class template and alias template arguments should be OK. */
19096 ;
19097 /* A non-type argument of integral or enumerated type must be a
19098 constant. */
19103 {
19107 }
19109 }
19111 static bool
19113 {
19118 {
19121 }
19125 }
19127 /* We're out of SFINAE context now, so generate diagnostics for the access
19128 errors we saw earlier when instantiating D from TMPL and ARGS. */
19130 static void
19132 {
19144 }
19146 /* Instantiate the indicated variable, function, or alias template TMPL with
19147 the template arguments in TARG_PTR. */
19149 static tree
19151 {
19153 tree fndecl;
19154 tree gen_tmpl;
19155 tree spec;
19163 /* If this function is a clone, handle it specially. */
19165 {
19166 tree spec;
19167 tree clone;
19169 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
19170 DECL_CLONED_FUNCTION. */
19176 /* Look for the clone. */
19180 /* We should always have found the clone by now. */
19183 }
19188 /* Check to see if we already have this specialization. */
19192 /* targ_ptr only has the innermost template args, so add the outer ones
19193 from tmpl, which could be either a partial instantiation or gen_tmpl (in
19194 the case of a non-dependent call within a template definition). */
19195 targ_ptr = (add_outermost_template_args
19197 targ_ptr));
19199 /* It would be nice to avoid hashing here and then again in tsubst_decl,
19200 but it doesn't seem to be on the hot path. */
19209 {
19211 {
19215 }
19217 }
19220 complain))
19223 /* We are building a FUNCTION_DECL, during which the access of its
19224 parameters and return types have to be checked. However this
19225 FUNCTION_DECL which is the desired context for access checking
19226 is not built yet. We solve this chicken-and-egg problem by
19227 deferring all checks until we have the FUNCTION_DECL. */
19230 /* Instantiation of the function happens in the context of the function
19231 template, not the context of the overload resolution we're doing. */
19233 /* If there are dependent arguments, e.g. because we're doing partial
19234 ordering, make sure processing_template_decl stays set. */
19238 {
19242 }
19248 {
19249 /* We need to determine if we're using a partial or explicit
19250 specialization now, because the type of the variable could be
19251 different. */
19257 {
19262 }
19263 }
19265 /* Substitute template parameters to obtain the specialization. */
19273 {
19276 }
19278 /* The DECL_TI_TEMPLATE should always be the immediate parent
19279 template, not the most general template. */
19283 /* Now we know the specialization, compute access previously
19284 deferred. Do no access control for inheriting constructors,
19285 as we already checked access for the inherited constructor. */
19288 {
19293 }
19296 /* If we've just instantiated the main entry point for a function,
19297 instantiate all the alternate entry points as well. We do this
19298 by cloning the instantiation of the main entry point, not by
19299 instantiating the template clones. */
19304 {
19306 {
19307 /* Remember to reinstantiate when we're out of SFINAE so the user
19308 can see the errors. */
19310 }
19312 }
19314 }
19316 /* Wrapper for instantiate_template_1. */
19318 tree
19320 {
19321 tree ret;
19326 }
19328 /* Instantiate the alias template TMPL with ARGS. Also push a template
19329 instantiation level, which instantiate_template doesn't do because
19330 functions and variables have sufficient context established by the
19331 callers. */
19333 static tree
19335 {
19341 args =
19351 }
19353 /* PARM is a template parameter pack for FN. Returns true iff
19354 PARM is used in a deducible way in the argument list of FN. */
19356 static bool
19358 {
19361 {
19363 tree packs;
19369 {
19370 /* The template parameter pack is used in a function parameter
19371 pack. If this is the end of the parameter list, the
19372 template parameter pack is deducible. */
19375 else
19376 /* Otherwise, not. Well, it could be deduced from
19377 a non-pack parameter, but doing so would end up with
19378 a deduction mismatch, so don't bother. */
19380 }
19381 }
19382 /* The template parameter pack isn't used in any function parameter
19383 packs, but it might be used deeper, e.g. tuple<Args...>. */
19385 }
19387 /* Subroutine of fn_type_unification: check non-dependent parms for
19388 convertibility. */
19390 static int
19394 {
19395 /* Non-constructor methods need to leave a conversion for 'this', which
19396 isn't included in nargs here. */
19402 {
19408 /* For a function parameter pack that occurs at the end of the
19409 parameter-declaration-list, the type A of each remaining
19410 argument of the call is compared with the type P of the
19411 declarator-id of the function parameter pack. */
19417 /* For a function parameter pack that does not occur at the
19418 end of the parameter-declaration-list, the type of the
19419 parameter pack is a non-deduced context. */
19423 {
19431 }
19434 }
19437 }
19439 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
19440 NARGS elements of the arguments that are being used when calling
19441 it. TARGS is a vector into which the deduced template arguments
19442 are placed.
19444 Returns either a FUNCTION_DECL for the matching specialization of FN or
19445 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
19446 true, diagnostics will be printed to explain why it failed.
19448 If FN is a conversion operator, or we are trying to produce a specific
19449 specialization, RETURN_TYPE is the return type desired.
19451 The EXPLICIT_TARGS are explicit template arguments provided via a
19452 template-id.
19454 The parameter STRICT is one of:
19456 DEDUCE_CALL:
19457 We are deducing arguments for a function call, as in
19458 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
19459 deducing arguments for a call to the result of a conversion
19460 function template, as in [over.call.object].
19462 DEDUCE_CONV:
19463 We are deducing arguments for a conversion function, as in
19464 [temp.deduct.conv].
19466 DEDUCE_EXACT:
19467 We are deducing arguments when doing an explicit instantiation
19468 as in [temp.explicit], when determining an explicit specialization
19469 as in [temp.expl.spec], or when taking the address of a function
19470 template, as in [temp.deduct.funcaddr]. */
19472 tree
19474 tree explicit_targs,
19475 tree targs,
19478 tree return_type,
19479 unification_kind_t strict,
19484 {
19485 tree parms;
19486 tree fntype;
19502 full_targs = (add_outermost_template_args
19504 targs));
19509 /* In C++0x, it's possible to have a function template whose type depends
19510 on itself recursively. This is most obvious with decltype, but can also
19511 occur with enumeration scope (c++/48969). So we need to catch infinite
19512 recursion and reject the substitution at deduction time; this function
19513 will return error_mark_node for any repeated substitution.
19515 This also catches excessive recursion such as when f<N> depends on
19516 f<N-1> across all integers, and returns error_mark_node for all the
19517 substitutions back up to the initial one.
19519 This is, of course, not reentrant. */
19528 {
19529 /* [temp.deduct]
19531 The specified template arguments must match the template
19532 parameters in kind (i.e., type, nontype, template), and there
19533 must not be more arguments than there are parameters;
19534 otherwise type deduction fails.
19536 Nontype arguments must match the types of the corresponding
19537 nontype template parameters, or must be convertible to the
19538 types of the corresponding nontype parameters as specified in
19539 _temp.arg.nontype_, otherwise type deduction fails.
19541 All references in the function type of the function template
19542 to the corresponding template parameters are replaced by the
19543 specified template argument values. If a substitution in a
19544 template parameter or in the function type of the function
19545 template results in an invalid type, type deduction fails. */
19556 explicit_targs);
19558 /* Adjust any explicit template arguments before entering the
19559 substitution context. */
19560 explicit_targs
19562 complain,
19568 /* Substitute the explicit args into the function type. This is
19569 necessary so that, for instance, explicitly declared function
19570 arguments can match null pointed constants. If we were given
19571 an incomplete set of explicit args, we must not do semantic
19572 processing during substitution as we could create partial
19573 instantiations. */
19575 {
19580 /* Dig out the actual parm. */
19583 {
19586 }
19588 {
19591 }
19594 /* No explicit argument for this template parameter. */
19598 {
19599 /* Mark the argument pack as "incomplete". We could
19600 still deduce more arguments during unification.
19601 We remove this mark in type_unification_real. */
19603 {
19607 }
19609 /* We have some incomplete argument packs. */
19611 }
19612 }
19615 {
19618 }
19621 /* Ignore any access checks; we'll see them again in
19622 instantiate_template and they might have the wrong
19623 access path at this point. */
19635 /* Place the explicitly specified arguments in TARGS. */
19639 }
19641 /* Never do unification on the 'this' parameter. */
19645 {
19646 /* We're deducing for a call to the result of a template conversion
19647 function. The parms we really want are in return_type. */
19651 }
19653 {
19662 }
19664 /* We allow incomplete unification without an error message here
19665 because the standard doesn't seem to explicitly prohibit it. Our
19666 callers must be ready to deal with unification failures in any
19667 event. */
19669 /* If we aren't explaining yet, push tinst context so we can see where
19670 any errors (e.g. from class instantiations triggered by instantiation
19671 of default template arguments) come from. If we are explaining, this
19672 context is redundant. */
19674 {
19677 }
19679 /* type_unification_real will pass back any access checks from default
19680 template argument substitution. */
19692 /* Now that we have bindings for all of the template arguments,
19693 ensure that the arguments deduced for the template template
19694 parameters have compatible template parameter lists. We cannot
19695 check this property before we have deduced all template
19696 arguments, because the template parameter types of a template
19697 template parameter might depend on prior template parameters
19698 deduced after the template template parameter. The following
19699 ill-formed example illustrates this issue:
19701 template<typename T, template<T> class C> void f(C<5>, T);
19703 template<int N> struct X {};
19705 void g() {
19706 f(X<5>(), 5l); // error: template argument deduction fails
19707 }
19709 The template parameter list of 'C' depends on the template type
19710 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
19711 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
19712 time that we deduce 'C'. */
19715 {
19718 }
19720 /* DR 1391: All parameters have args, now check non-dependent parms for
19721 convertibility. */
19726 /* All is well so far. Now, check:
19728 [temp.deduct]
19730 When all template arguments have been deduced, all uses of
19731 template parameters in nondeduced contexts are replaced with
19732 the corresponding deduced argument values. If the
19733 substitution results in an invalid type, as described above,
19734 type deduction fails. */
19736 {
19739 }
19741 /* Also collect access checks from the instantiation. */
19754 /* Now perform any access checks encountered during substitution. */
19761 /* If we're looking for an exact match, check that what we got
19762 is indeed an exact match. It might not be if some template
19763 parameters are used in non-deduced contexts. But don't check
19764 for an exact match if we have dependent template arguments;
19765 in that case we're doing partial ordering, and we already know
19766 that we have two candidates that will provide the actual type. */
19768 {
19772 tree sarg
19778 {
19782 }
19783 }
19785 /* After doing deduction with the inherited constructor, actually return an
19786 instantiation of the inheriting constructor. */
19792 fail:
19795 {
19797 /* Reset once we're all the way out. */
19799 }
19802 }
19804 /* Adjust types before performing type deduction, as described in
19805 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19806 sections are symmetric. PARM is the type of a function parameter
19807 or the return type of the conversion function. ARG is the type of
19808 the argument passed to the call, or the type of the value
19809 initialized with the result of the conversion function.
19810 ARG_EXPR is the original argument expression, which may be null. */
19812 static int
19816 tree arg_expr)
19817 {
19821 {
19826 /* Swap PARM and ARG throughout the remainder of this
19827 function; the handling is precisely symmetric since PARM
19828 will initialize ARG rather than vice versa. */
19833 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19834 too, but here handle it by stripping the reference from PARM
19835 rather than by adding it to ARG. */
19843 /* Nothing else to do in this case. */
19848 }
19851 {
19852 /* [temp.deduct.call]
19854 If P is not a reference type:
19856 --If A is an array type, the pointer type produced by the
19857 array-to-pointer standard conversion (_conv.array_) is
19858 used in place of A for type deduction; otherwise,
19860 --If A is a function type, the pointer type produced by
19861 the function-to-pointer standard conversion
19862 (_conv.func_) is used in place of A for type deduction;
19863 otherwise,
19865 --If A is a cv-qualified type, the top level
19866 cv-qualifiers of A's type are ignored for type
19867 deduction. */
19872 else
19874 }
19876 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19877 reference to a cv-unqualified template parameter that does not represent a
19878 template parameter of a class template (during class template argument
19879 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19880 an lvalue, the type "lvalue reference to A" is used in place of A for type
19881 deduction. */
19888 /* try_one_overload doesn't provide an arg_expr, but
19889 functions are always lvalues. */
19893 /* [temp.deduct.call]
19895 If P is a cv-qualified type, the top level cv-qualifiers
19896 of P's type are ignored for type deduction. If P is a
19897 reference type, the type referred to by P is used for
19898 type deduction. */
19901 {
19904 }
19906 /* DR 322. For conversion deduction, remove a reference type on parm
19907 too (which has been swapped into ARG). */
19912 }
19914 /* Subroutine of fn_type_unification. PARM is a function parameter of a
19915 template which doesn't contain any deducible template parameters; check if
19916 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19917 unify_one_argument. */
19919 static int
19923 {
19924 tree type;
19928 else
19936 {
19939 }
19941 {
19945 /* Avoid recalculating this in add_function_candidate. */
19946 ok = (*conv_p
19948 else
19952 }
19956 else
19958 }
19962 /* Returns true iff the expression EXPR is one from which a template
19963 argument can be deduced. In other words, if it's an undecorated
19964 use of a template non-type parameter. */
19966 static bool
19968 {
19969 /* Strip implicit conversions. */
19973 }
19975 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19976 deducible way; that is, if it has a max value of <PARM> - 1. */
19978 static bool
19980 {
19989 }
19991 /* Returns true iff the template arguments ARGS use a template parameter
19992 in a deducible way. */
19994 static bool
19996 {
19998 {
20003 else
20004 {
20011 else
20013 }
20016 }
20018 }
20020 /* Returns true iff TYPE contains any deducible references to template
20021 parameters, as per 14.8.2.5. */
20023 static bool
20025 {
20029 /* T
20030 cv-list T
20031 TT<T>
20032 TT<i>
20033 TT<> */
20038 /* T*
20039 T&
20040 T&& */
20044 /* T[integer-constant ]
20045 type [i] */
20050 /* T type ::*
20051 type T::*
20052 T T::*
20053 T (type ::*)()
20054 type (T::*)()
20055 type (type ::*)(T)
20056 type (T::*)(T)
20057 T (type ::*)(T)
20058 T (T::*)()
20059 T (T::*)(T) */
20062 || (uses_deducible_template_parms
20065 /* template-name <T> (where template-name refers to a class template)
20066 template-name <i> (where template-name refers to a class template) */
20073 /* type (T)
20074 T()
20075 T(T) */
20078 {
20087 }
20090 }
20092 /* Subroutine of type_unification_real and unify_pack_expansion to
20093 handle unification of a single P/A pair. Parameters are as
20094 for those functions. */
20096 static int
20100 {
20107 /* We can't deduce anything from this, but we might get all the
20108 template args from other function args. */
20111 /* Implicit conversions (Clause 4) will be performed on a function
20112 argument to convert it to the type of the corresponding function
20113 parameter if the parameter type contains no template-parameters that
20114 participate in template argument deduction. */
20117 /* For function parameters with no deducible template parameters,
20118 just return. We'll check non-dependent conversions later. */
20122 {
20124 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
20125 | UNIFY_ALLOW_MORE_CV_QUAL
20139 }
20141 /* We only do these transformations if this is the top-level
20142 parameter_type_list in a call or declaration matching; in other
20143 situations (nested function declarators, template argument lists) we
20144 won't be comparing a type to an expression, and we don't do any type
20145 adjustments. */
20147 {
20149 {
20152 {
20153 /* [temp.deduct.type] A template-argument can be
20154 deduced from a pointer to function or pointer
20155 to member function argument if the set of
20156 overloaded functions does not contain function
20157 templates and at most one of a set of
20158 overloaded functions provides a unique
20159 match. */
20163 /* If a unique match was not found, this is a
20164 non-deduced context, so we still succeed. */
20166 }
20172 }
20174 arg_strict |=
20176 }
20177 else
20182 /* For deduction from an init-list we need the actual list. */
20186 }
20188 /* for_each_template_parm callback that always returns 0. */
20190 static int
20192 {
20194 }
20196 /* for_each_template_parm any_fn callback to handle deduction of a template
20197 type argument from the type of an array bound. */
20199 static int
20201 {
20209 {
20215 }
20217 /* Keep walking. */
20219 }
20221 /* Try to deduce any not-yet-deduced template type arguments from the type of
20222 an array bound. This is handled separately from unify because 14.8.2.5 says
20223 "The type of a type parameter is only deduced from an array bound if it is
20224 not otherwise deduced." */
20226 static void
20228 {
20233 }
20235 /* Most parms like fn_type_unification.
20237 If SUBR is 1, we're being called recursively (to unify the
20238 arguments of a function or method parameter of a function
20239 template).
20241 CHECKS is a pointer to a vector of access checks encountered while
20242 substituting default template arguments. */
20244 static int
20246 tree full_targs,
20247 tree xparms,
20251 unification_kind_t strict,
20254 {
20259 tree parms;
20270 /* Reset the number of non-defaulted template arguments contained
20271 in TARGS. */
20274 again:
20282 {
20287 /* For a function parameter pack that occurs at the end of the
20288 parameter-declaration-list, the type A of each remaining
20289 argument of the call is compared with the type P of the
20290 declarator-id of the function parameter pack. */
20296 /* For a function parameter pack that does not occur at the
20297 end of the parameter-declaration-list, the type of the
20298 parameter pack is a non-deduced context. */
20305 explain_p))
20307 }
20312 {
20313 /* Unify the remaining arguments with the pack expansion type. */
20314 tree argvec;
20317 /* Allocate a TREE_VEC and copy in all of the arguments */
20322 /* Copy the parameter into parmvec. */
20328 /* Advance to the end of the list of parameters. */
20330 }
20332 /* Fail if we've reached the end of the parm list, and more args
20333 are present, and the parm list isn't variadic. */
20336 /* Fail if parms are left and they don't have default values and
20337 they aren't all deduced as empty packs (c++/57397). This is
20338 consistent with sufficient_parms_p. */
20341 {
20345 do
20346 {
20349 count++;
20351 }
20355 type_pack_p);
20356 }
20359 {
20360 tsubst_flags_t complain = (explain_p
20361 ? tf_warning_or_error
20366 {
20370 /* Clear the "incomplete" flags on all argument packs now so that
20371 substituting them into later default arguments works. */
20373 {
20376 }
20384 {
20389 }
20391 /* If this is an undeduced nontype parameter that depends on
20392 a type parameter, try another pass; its type may have been
20393 deduced from a later argument than the one from which
20394 this parameter can be deduced. */
20398 {
20401 }
20403 /* Core issue #226 (C++0x) [temp.deduct]:
20405 If a template argument has not been deduced, its
20406 default template argument, if any, is used.
20408 When we are in C++98 mode, TREE_PURPOSE will either
20409 be NULL_TREE or ERROR_MARK_NODE, so we do not need
20410 to explicitly check cxx_dialect here. */
20412 /* OK, there is a default argument. Wait until after the
20413 conversion check to do substitution. */
20416 /* If the type parameter is a parameter pack, then it will
20417 be deduced to an empty parameter pack. */
20419 {
20420 tree arg;
20423 {
20426 }
20427 else
20434 }
20437 }
20439 /* Now substitute into the default template arguments. */
20441 {
20457 {
20458 /* The type of this non-type parameter depends on undeduced
20459 parameters. Don't try to use its default argument yet,
20460 since we might deduce an argument for it on the next pass,
20461 but do check whether the arguments we already have cause
20462 substitution failure, so that that happens before we try
20463 later default arguments (78489). */
20466 NULL_TREE);
20470 else
20472 }
20473 else
20474 {
20477 {
20478 /* First instatiate in template context, in case we still
20479 depend on undeduced template parameters. */
20482 NULL_TREE);
20486 /* We replaced all the tparms, substitute again out of
20487 template context. */
20489 }
20492 NULL_TREE);
20499 else
20501 }
20510 {
20512 /* The position of the first default template argument,
20513 is also the number of non-defaulted arguments in TARGS.
20514 Record that. */
20517 }
20518 }
20522 }
20528 }
20530 /* Subroutine of type_unification_real. Args are like the variables
20531 at the call site. ARG is an overloaded function (or template-id);
20532 we try deducing template args from each of the overloads, and if
20533 only one succeeds, we go with that. Modifies TARGS and returns
20534 true on success. */
20536 static bool
20538 tree targs,
20539 tree parm,
20540 tree arg,
20541 unification_kind_t strict,
20544 {
20551 {
20554 }
20555 else
20559 /* Handle `&x' where `x' is some static or non-static member
20560 function name. */
20566 /* Strip baselink information. */
20571 {
20572 /* If we got some explicit template args, we need to plug them into
20573 the affected templates before we try to unify, in case the
20574 explicit args will completely resolve the templates in question. */
20581 {
20594 {
20599 {
20602 }
20603 }
20606 }
20607 /* If no templates (or more than one) are fully resolved by the
20608 explicit arguments, this template-id is a non-deduced context; it
20609 could still be OK if we deduce all template arguments for the
20610 enclosing call through other arguments. */
20613 }
20616 /* If ARG is, for example, "(0, &f)" then its type will be unknown
20617 -- but the deduction does not succeed because the expression is
20618 not just the function on its own. */
20620 else
20622 {
20627 {
20630 }
20631 }
20633 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20634 to function or pointer to member function argument if the set of
20635 overloaded functions does not contain function templates and at most
20636 one of a set of overloaded functions provides a unique match.
20638 So if we found multiple possibilities, we return success but don't
20639 deduce anything. */
20642 {
20646 {
20651 /* Don't forget explicit template arguments in a pack. */
20655 }
20656 }
20661 }
20663 /* Core DR 115: In contexts where deduction is done and fails, or in
20664 contexts where deduction is not done, if a template argument list is
20665 specified and it, along with any default template arguments, identifies
20666 a single function template specialization, then the template-id is an
20667 lvalue for the function template specialization. */
20669 tree
20671 {
20684 {
20687 }
20689 {
20692 }
20694 {
20697 }
20700 {
20704 /* If we got some explicit template args, we need to plug them into
20705 the affected templates before we try to unify, in case the
20706 explicit args will completely resolve the templates in question. */
20714 {
20727 {
20730 {
20733 }
20735 {
20738 }
20739 }
20740 }
20742 {
20750 {
20751 tree base
20754 }
20758 }
20760 /* There were no good options and at least one bad one, so let the
20761 user know what the problem is. */
20763 }
20765 }
20767 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20768 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20769 different overloads deduce different arguments for a given parm.
20770 ADDR_P is true if the expression for which deduction is being
20771 performed was of the form "& fn" rather than simply "fn".
20773 Returns 1 on success. */
20775 static int
20777 tree orig_targs,
20778 tree targs,
20779 tree parm,
20780 tree arg,
20781 unification_kind_t strict,
20785 {
20787 tree tempargs;
20793 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20794 to function or pointer to member function argument if the set of
20795 overloaded functions does not contain function templates and at most
20796 one of a set of overloaded functions provides a unique match.
20798 So if this is a template, just return success. */
20810 /* We don't copy orig_targs for this because if we have already deduced
20811 some template args from previous args, unify would complain when we
20812 try to deduce a template parameter for the same argument, even though
20813 there isn't really a conflict. */
20820 /* First make sure we didn't deduce anything that conflicts with
20821 explicitly specified args. */
20823 {
20830 /* Since we're unifying against ourselves, we will fill in
20831 template args used in the function parm list with our own
20832 template parms. Discard them. */
20835 {
20836 /* Check that the argument at each index of the deduced argument pack
20837 is equivalent to the corresponding explicitly specified argument.
20838 We may have deduced more arguments than were explicitly specified,
20839 and that's OK. */
20841 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20842 that's wrong if we deduce the same argument pack from multiple
20843 function arguments: it's only incomplete the first time. */
20856 }
20859 }
20862 {
20867 }
20870 }
20872 /* PARM is a template class (perhaps with unbound template
20873 parameters). ARG is a fully instantiated type. If ARG can be
20874 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20875 TARGS are as for unify. */
20877 static tree
20880 {
20881 tree copy_of_targs;
20891 /* We need to make a new template argument vector for the call to
20892 unify. If we used TARGS, we'd clutter it up with the result of
20893 the attempted unification, even if this class didn't work out.
20894 We also don't want to commit ourselves to all the unifications
20895 we've already done, since unification is supposed to be done on
20896 an argument-by-argument basis. In other words, consider the
20897 following pathological case:
20899 template <int I, int J, int K>
20900 struct S {};
20902 template <int I, int J>
20903 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20905 template <int I, int J, int K>
20906 void f(S<I, J, K>, S<I, I, I>);
20908 void g() {
20909 S<0, 0, 0> s0;
20910 S<0, 1, 2> s2;
20912 f(s0, s2);
20913 }
20915 Now, by the time we consider the unification involving `s2', we
20916 already know that we must have `f<0, 0, 0>'. But, even though
20917 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20918 because there are two ways to unify base classes of S<0, 1, 2>
20919 with S<I, I, I>. If we kept the already deduced knowledge, we
20920 would reject the possibility I=1. */
20924 {
20928 }
20930 /* If unification failed, we're done. */
20936 }
20938 /* Given a template type PARM and a class type ARG, find the unique
20939 base type in ARG that is an instance of PARM. We do not examine
20940 ARG itself; only its base-classes. If there is not exactly one
20941 appropriate base class, return NULL_TREE. PARM may be the type of
20942 a partial specialization, as well as a plain template type. Used
20943 by unify. */
20945 static enum template_base_result
20948 {
20950 tree binfo;
20956 {
20957 /* The type could not be completed. */
20960 }
20962 /* Walk in inheritance graph order. The search order is not
20963 important, and this avoids multiple walks of virtual bases. */
20965 {
20970 {
20971 /* If there is more than one satisfactory baseclass, then:
20973 [temp.deduct.call]
20975 If they yield more than one possible deduced A, the type
20976 deduction fails.
20978 applies. */
20980 {
20983 }
20986 }
20987 }
20991 }
20993 /* Returns the level of DECL, which declares a template parameter. */
20995 static int
20997 {
20999 {
21009 }
21011 }
21013 /* Decide whether ARG can be unified with PARM, considering only the
21014 cv-qualifiers of each type, given STRICT as documented for unify.
21015 Returns nonzero iff the unification is OK on that basis. */
21017 static int
21019 {
21025 {
21026 /* Although a CVR qualifier is ignored when being applied to a
21027 substituted template parameter ([8.3.2]/1 for example), that
21028 does not allow us to unify "const T" with "int&" because both
21029 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
21030 It is ok when we're allowing additional CV qualifiers
21031 at the outer level [14.8.2.1]/3,1st bullet. */
21041 }
21052 }
21054 /* Determines the LEVEL and INDEX for the template parameter PARM. */
21055 void
21057 {
21061 {
21064 }
21065 else
21066 {
21069 }
21070 }
21072 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
21073 do { \
21074 if (unify (TP, TA, P, A, S, EP)) \
21075 return 1; \
21076 } while (0)
21078 /* Unifies the remaining arguments in PACKED_ARGS with the pack
21079 expansion at the end of PACKED_PARMS. Returns 0 if the type
21080 deduction succeeds, 1 otherwise. STRICT is the same as in
21081 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
21082 function call argument list. We'll need to adjust the arguments to make them
21083 types. SUBR tells us if this is from a recursive call to
21084 type_unification_real, or for comparing two template argument
21085 lists. */
21087 static int
21091 {
21092 tree parm
21098 /* Add in any args remembered from an earlier partial instantiation. */
21106 /* Determine the parameter packs we will be deducing from the
21107 pattern, and record their current deductions. */
21110 {
21114 /* Only template parameter packs can be deduced, not e.g. function
21115 parameter packs or __bases or __integer_pack. */
21119 /* Determine the index and level of this parameter pack. */
21124 /* Keep track of the parameter packs and their corresponding
21125 argument packs. */
21128 }
21130 /* Loop through all of the arguments that have not yet been
21131 unified and unify each with the pattern. */
21133 {
21134 tree parm;
21138 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
21139 or the element of its argument pack at the current index if
21140 this argument was explicitly specified. */
21142 {
21151 {
21154 }
21156 }
21158 /* If we had explicit template arguments, substitute them into the
21159 pattern before deduction. */
21161 {
21162 /* Some arguments might still be unspecified or dependent. */
21170 NULL_TREE);
21175 }
21176 else
21179 /* Unify the pattern with the current argument. */
21181 explain_p))
21184 /* For each parameter pack, collect the deduced value. */
21186 {
21192 }
21193 }
21195 /* Verify that the results of unification with the parameter packs
21196 produce results consistent with what we've seen before, and make
21197 the deduced argument packs available. */
21199 {
21206 /* By default keep the original deduced argument pack.
21207 If necessary, more specific code is going to update the
21208 resulting deduced argument later down in this function. */
21212 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
21213 actually deduce anything. */
21221 {
21222 /* If we had fewer function args than explicit template args,
21223 just use the explicits. */
21228 }
21231 {
21232 tree result;
21233 /* Build the deduced *_ARGUMENT_PACK. */
21235 {
21238 }
21239 else
21244 /* Note the deduced argument packs for this parameter
21245 pack. */
21247 }
21251 {
21252 /* We only had the explicitly-provided arguments before, but
21253 now we have a complete set of arguments. */
21259 }
21260 else
21261 {
21267 /* Inconsistent unification of this parameter pack. */
21269 bad_old_arg,
21270 bad_new_arg);
21271 }
21272 }
21275 }
21277 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
21278 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
21279 parameters and return value are as for unify. */
21281 static int
21285 {
21286 tree parm_max;
21287 tree arg_max;
21291 /* Our representation of array types uses "N - 1" as the
21292 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
21293 not an integer constant. We cannot unify arbitrarily
21294 complex expressions, so we eliminate the MINUS_EXPRs
21295 here. */
21299 {
21302 }
21306 {
21307 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
21308 trying to unify the type of a variable with the type
21309 of a template parameter. For example:
21311 template <unsigned int N>
21312 void f (char (&) [N]);
21313 int g();
21314 void h(int i) {
21315 char a[g(i)];
21316 f(a);
21317 }
21319 Here, the type of the ARG will be "int [g(i)]", and
21320 may be a SAVE_EXPR, etc. */
21324 }
21326 /* If only one of the bounds used a MINUS_EXPR, compensate
21327 by adding one to the other bound. */
21330 integer_type_node,
21331 parm_max,
21332 integer_one_node);
21335 integer_type_node,
21336 arg_max,
21337 integer_one_node);
21341 }
21343 /* Returns whether T, a P or A in unify, is a type, template or expression. */
21347 static pa_kind_t
21349 {
21358 else
21360 }
21362 /* Deduce the value of template parameters. TPARMS is the (innermost)
21363 set of template parameters to a template. TARGS is the bindings
21364 for those template parameters, as determined thus far; TARGS may
21365 include template arguments for outer levels of template parameters
21366 as well. PARM is a parameter to a template function, or a
21367 subcomponent of that parameter; ARG is the corresponding argument.
21368 This function attempts to match PARM with ARG in a manner
21369 consistent with the existing assignments in TARGS. If more values
21370 are deduced, then TARGS is updated.
21372 Returns 0 if the type deduction succeeds, 1 otherwise. The
21373 parameter STRICT is a bitwise or of the following flags:
21375 UNIFY_ALLOW_NONE:
21376 Require an exact match between PARM and ARG.
21377 UNIFY_ALLOW_MORE_CV_QUAL:
21378 Allow the deduced ARG to be more cv-qualified (by qualification
21379 conversion) than ARG.
21380 UNIFY_ALLOW_LESS_CV_QUAL:
21381 Allow the deduced ARG to be less cv-qualified than ARG.
21382 UNIFY_ALLOW_DERIVED:
21383 Allow the deduced ARG to be a template base class of ARG,
21384 or a pointer to a template base class of the type pointed to by
21385 ARG.
21386 UNIFY_ALLOW_INTEGER:
21387 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
21388 case for more information.
21389 UNIFY_ALLOW_OUTER_LEVEL:
21390 This is the outermost level of a deduction. Used to determine validity
21391 of qualification conversions. A valid qualification conversion must
21392 have const qualified pointers leading up to the inner type which
21393 requires additional CV quals, except at the outer level, where const
21394 is not required [conv.qual]. It would be normal to set this flag in
21395 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
21396 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
21397 This is the outermost level of a deduction, and PARM can be more CV
21398 qualified at this point.
21399 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
21400 This is the outermost level of a deduction, and PARM can be less CV
21401 qualified at this point. */
21403 static int
21406 {
21408 tree targ;
21409 tree tparm;
21411 tsubst_flags_t complain = (explain_p
21412 ? tf_warning_or_error
21415 /* I don't think this will do the right thing with respect to types.
21416 But the only case I've seen it in so far has been array bounds, where
21417 signedness is the only information lost, and I think that will be
21418 okay. */
21426 /* We can't deduce anything from this, but we might get all the
21427 template args from other function args. */
21433 /* If PARM uses template parameters, then we can't bail out here,
21434 even if ARG == PARM, since we won't record unifications for the
21435 template parameters. We might need them if we're trying to
21436 figure out which of two things is more specialized. */
21440 /* Handle init lists early, so the rest of the function can assume
21441 we're dealing with a type. */
21443 {
21448 /* Replace T with std::initializer_list<T> for deduction. */
21455 /* We can only deduce from an initializer list argument if the
21456 parameter is std::initializer_list or an array; otherwise this
21457 is a non-deduced context. */
21462 else
21463 {
21465 /* Deduction is defined in terms of a single type, so just punt
21466 on the (bizarre) std::initializer_list<T...>. */
21469 }
21474 /* If ELTTYPE has no deducible template parms, skip deduction from
21476 else
21478 {
21485 {
21489 /* It should only be possible to get here for a call. */
21491 elt_strict |= maybe_adjust_types_for_deduction
21494 }
21497 explain_p);
21498 }
21502 {
21503 /* Also deduce from the length of the initializer list. */
21510 }
21512 /* If the std::initializer_list<T> deduction worked, replace the
21513 deduced A with std::initializer_list<A>. */
21515 {
21520 }
21522 }
21524 /* If parm and arg aren't the same kind of thing (template, type, or
21525 expression), fail early. */
21529 /* Immediately reject some pairs that won't unify because of
21530 cv-qualification mismatches. */
21533 /* It is the elements of the array which hold the cv quals of an array
21534 type, and the elements might be template type parms. We'll check
21535 when we recurse. */
21537 /* We check the cv-qualifiers when unifying with template type
21538 parameters below. We want to allow ARG `const T' to unify with
21539 PARM `T' for example, when computing which of two templates
21540 is more specialized, for example. */
21554 {
21558 /* In a type which contains a nested-name-specifier, template
21559 argument values cannot be deduced for template parameters used
21560 within the nested-name-specifier. */
21572 /* The PARM is not one we're trying to unify. Just check
21573 to see if it matches ARG. */
21574 {
21579 else
21581 }
21588 /* Check for mixed types and values. */
21596 {
21599 {
21600 /* First try to match ARG directly. */
21602 explain_p);
21604 {
21605 /* Otherwise, look for a suitable base of ARG, as below. */
21612 }
21613 }
21614 /* ARG must be constructed from a template class or a template
21615 template parameter. */
21620 /* Deduce arguments T, i from TT<T> or TT<i>. */
21626 /* Fall through to deduce template name. */
21627 }
21631 {
21632 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
21634 /* Simple cases: Value already set, does match or doesn't. */
21639 }
21640 else
21641 {
21642 /* If PARM is `const T' and ARG is only `int', we don't have
21643 a match unless we are allowing additional qualification.
21644 If ARG is `const int' and PARM is just `T' that's OK;
21645 that binds `const int' to `T'. */
21650 /* Consider the case where ARG is `const volatile int' and
21651 PARM is `const T'. Then, T should be `volatile int'. */
21652 arg = cp_build_qualified_type_real
21657 /* Simple cases: Value already set, does match or doesn't. */
21663 /* Make sure that ARG is not a variable-sized array. (Note
21664 that were talking about variable-sized arrays (like
21665 `int[n]'), rather than arrays of unknown size (like
21666 `int[]').) We'll get very confused by such a type since
21667 the bound of the array is not constant, and therefore
21668 not mangleable. Besides, such types are not allowed in
21669 ISO C++, so we can do as we please here. We do allow
21670 them for 'auto' deduction, since that isn't ABI-exposed. */
21674 /* Strip typedefs as in convert_template_argument. */
21676 }
21678 /* If ARG is a parameter pack or an expansion, we cannot unify
21679 against it unless PARM is also a parameter pack. */
21684 /* If the argument deduction results is a METHOD_TYPE,
21685 then there is a problem.
21686 METHOD_TYPE doesn't map to any real C++ type the result of
21687 the deduction can not be of that type. */
21701 {
21702 /* The PARM is not one we're trying to unify. Just check
21703 to see if it matches ARG. */
21709 }
21715 {
21719 /* We're deducing from an array bound, the type doesn't matter. */
21725 }
21727 /* [temp.deduct.type] If, in the declaration of a function template
21728 with a non-type template-parameter, the non-type
21729 template-parameter is used in an expression in the function
21730 parameter-list and, if the corresponding template-argument is
21731 deduced, the template-argument type shall match the type of the
21732 template-parameter exactly, except that a template-argument
21733 deduced from an array bound may be of any integral type.
21734 The non-type parameter might use already deduced type parameters. */
21737 /* We don't have enough levels of args to do any substitution. This
21739 else
21740 {
21746 {
21750 }
21751 }
21754 /* Template-parameter dependent expression. Just accept it for now.
21755 It will later be processed in convert_template_argument. */
21756 ;
21762 /* Convert the ARG to the type of PARM; the deduced non-type
21763 template argument must exactly match the types of the
21764 corresponding parameter. */
21767 {
21768 /* We haven't deduced the type of this parameter yet. */
21770 /* We deduce from array bounds in try_array_deduction. */
21772 {
21773 /* Deduce it from the non-type argument. */
21778 }
21779 else
21780 /* Try again later. */
21782 }
21783 else
21786 /* If ARG is a parameter pack or an expansion, we cannot unify
21787 against it unless PARM is also a parameter pack. */
21792 {
21795 }
21800 {
21801 /* A pointer-to-member constant can be unified only with
21802 another constant. */
21806 /* Just unify the class member. It would be useless (and possibly
21807 wrong, depending on the strict flags) to unify also
21808 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21809 arg refer to the same variable, even if through different
21810 classes. For instance:
21812 struct A { int x; };
21813 struct B : A { };
21815 Unification of &A::x and &B::x must succeed. */
21818 }
21821 {
21825 /* [temp.deduct.call]
21827 A can be another pointer or pointer to member type that can
21828 be converted to the deduced A via a qualification
21829 conversion (_conv.qual_).
21831 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21832 This will allow for additional cv-qualification of the
21833 pointed-to types if appropriate. */
21836 /* The derived-to-base conversion only persists through one
21837 level of pointers. */
21842 }
21874 /* We have already checked cv-qualification at the top of the
21875 function. */
21879 /* As far as unification is concerned, this wins. Later checks
21880 will invalidate it if necessary. */
21883 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21884 /* Type INTEGER_CST can come from ordinary constant template args. */
21896 {
21906 /* Check for pack expansions in the parameters. */
21908 {
21910 {
21912 /* We can unify against something with a trailing
21913 parameter pack. */
21915 else
21916 /* [temp.deduct.type]/9: If the template argument list of
21917 P contains a pack expansion that is not the last
21918 template argument, the entire template argument list
21919 is a non-deduced context. */
21921 }
21922 }
21924 /* If we don't have enough arguments to satisfy the parameters
21925 (not counting the pack expression at the end), or we have
21926 too many arguments for a parameter list that doesn't end in
21927 a pack expression, we can't unify. */
21933 /* Unify all of the parameters that precede the (optional)
21934 pack expression. */
21936 {
21941 }
21944 DEDUCE_EXACT,
21947 }
21955 {
21963 }
21968 {
21972 {
21973 /* First, we try to unify the PARM and ARG directly. */
21978 {
21979 /* Fallback to the special case allowed in
21980 [temp.deduct.call]:
21982 If P is a class, and P has the form
21983 template-id, then A can be a derived class of
21984 the deduced A. Likewise, if P is a pointer to
21985 a class of the form template-id, A can be a
21986 pointer to a derived class pointed to by the
21987 deduced A. */
21993 {
21994 /* Don't give the derived diagnostic if we're
21995 already dealing with the same template. */
21996 bool same_template
22002 }
22003 }
22004 }
22008 /* Perhaps PARM is something like S<U> and ARG is S<int>.
22009 Then, we should unify `int' and `U'. */
22011 else
22012 /* There's no chance of unification succeeding. */
22017 }
22024 {
22027 tree a;
22033 /* CV qualifications for methods can never be deduced, they must
22034 match exactly. We need to check them explicitly here,
22035 because type_unification_real treats them as any other
22036 cv-qualified parameter. */
22038 && (!check_cv_quals_for_unify
22066 {
22078 }
22081 }
22084 /* Unify a pointer to member with a pointer to member function, which
22085 deduces the type of the member as a function type. */
22087 {
22088 /* Check top-level cv qualifiers */
22096 /* Determine the type of the function we are unifying against. */
22100 }
22119 /* Matched cases are handled by the ARG == PARM test above. */
22123 /* We might get a variable as a non-type template argument in parm if the
22124 corresponding parameter is type-dependent. Make any necessary
22125 adjustments based on whether arg is a reference. */
22129 {
22134 }
22135 /* Now use the normal expression code to check whether they match. */
22146 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
22147 or UNDERLYING_TYPE nodes. */
22151 /* Unification fails if we hit an error node. */
22156 {
22166 }
22167 /* FALLTHRU */
22170 /* An unresolved overload is a nondeduced context. */
22174 expr:
22175 /* We must be looking at an expression. This can happen with
22176 something like:
22178 template <int I>
22179 void foo(S<I>, S<I + 2>);
22181 This is a "nondeduced context":
22183 [deduct.type]
22185 The nondeduced contexts are:
22187 --A type that is a template-id in which one or more of
22188 the template-arguments is an expression that references
22189 a template-parameter.
22191 In these cases, we assume deduction succeeded, but don't
22192 actually infer any unifications. */
22197 else
22199 }
22200 }
22201 #undef RECUR_AND_CHECK_FAILURE
22202 \f
22203 /* Note that DECL can be defined in this translation unit, if
22204 required. */
22206 static void
22208 {
22209 tree clone;
22213 }
22215 /* Called if RESULT is explicitly instantiated, or is a member of an
22216 explicitly instantiated class. */
22218 void
22220 {
22223 /* If this entity has already been written out, it's too late to
22224 make any modifications. */
22228 /* For anonymous namespace we don't need to do anything. */
22230 {
22233 }
22236 /* The TREE_PUBLIC flag for function declarations will have been
22237 set correctly by tsubst. */
22240 /* This might have been set by an earlier implicit instantiation. */
22245 else
22246 {
22249 /* Always make artificials weak. */
22252 /* For WIN32 we also want to put explicit instantiations in
22253 linkonce sections. */
22258 /* If the function has already been instantiated, clear DECL_EXTERNAL,
22259 since start_preparsed_function wouldn't have if we had an earlier
22260 extern explicit instantiation. */
22262 }
22264 /* If EXTERN_P, then this function will not be emitted -- unless
22265 followed by an explicit instantiation, at which point its linkage
22266 will be adjusted. If !EXTERN_P, then this function will be
22267 emitted here. In neither circumstance do we want
22268 import_export_decl to adjust the linkage. */
22270 }
22272 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
22273 important template arguments. If any are missing, we check whether
22274 they're important by using error_mark_node for substituting into any
22275 args that were used for partial ordering (the ones between ARGS and END)
22276 and seeing if it bubbles up. */
22278 static bool
22280 {
22285 {
22288 }
22290 {
22294 }
22296 }
22298 /* Given two function templates PAT1 and PAT2, return:
22300 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
22301 -1 if PAT2 is more specialized than PAT1.
22302 0 if neither is more specialized.
22304 LEN indicates the number of parameters we should consider
22305 (defaulted parameters should not be considered).
22307 The 1998 std underspecified function template partial ordering, and
22308 DR214 addresses the issue. We take pairs of arguments, one from
22309 each of the templates, and deduce them against each other. One of
22310 the templates will be more specialized if all the *other*
22311 template's arguments deduce against its arguments and at least one
22312 of its arguments *does* *not* deduce against the other template's
22313 corresponding argument. Deduction is done as for class templates.
22314 The arguments used in deduction have reference and top level cv
22315 qualifiers removed. Iff both arguments were originally reference
22316 types *and* deduction succeeds in both directions, an lvalue reference
22317 wins against an rvalue reference and otherwise the template
22318 with the more cv-qualified argument wins for that pairing (if
22319 neither is more cv-qualified, they both are equal). Unlike regular
22320 deduction, after all the arguments have been deduced in this way,
22321 we do *not* verify the deduced template argument values can be
22322 substituted into non-deduced contexts.
22324 The logic can be a bit confusing here, because we look at deduce1 and
22325 targs1 to see if pat2 is at least as specialized, and vice versa; if we
22326 can find template arguments for pat1 to make arg1 look like arg2, that
22327 means that arg2 is at least as specialized as arg1. */
22329 int
22331 {
22344 /* Remove the this parameter from non-static member functions. If
22345 one is a non-static member function and the other is not a static
22346 member function, remove the first parameter from that function
22347 also. This situation occurs for operator functions where we
22348 locate both a member function (with this pointer) and non-member
22349 operator (with explicit first operand). */
22351 {
22356 }
22358 {
22361 {
22362 len--;
22364 }
22365 }
22367 /* If only one is a conversion operator, they are unordered. */
22371 /* Consider the return type for a conversion function */
22373 {
22376 len++;
22377 }
22379 processing_template_decl++;
22385 /* Stop when an ellipsis is seen. */
22387 {
22398 {
22399 /* When both arguments are pack expansions, we need only
22400 unify the patterns themselves. */
22404 /* This is the last comparison we need to do. */
22406 }
22408 /* DR 1847: If a particular P contains no template-parameters that
22409 participate in template argument deduction, that P is not used to
22410 determine the ordering. */
22416 {
22420 }
22423 {
22427 }
22433 {
22439 /* Setup the parameter vector, which contains only ARG1. */
22442 /* Setup the argument vector, which contains the remaining
22443 arguments. */
22452 /* We cannot deduce in the other direction, because ARG1 is
22453 a pack expansion but ARG2 is not. */
22455 }
22457 {
22463 /* Setup the parameter vector, which contains only ARG1. */
22466 /* Setup the argument vector, which contains the remaining
22467 arguments. */
22476 /* We cannot deduce in the other direction, because ARG2 is
22477 a pack expansion but ARG1 is not.*/
22479 }
22481 else
22482 {
22483 /* The normal case, where neither argument is a pack
22484 expansion. */
22491 }
22493 /* If we couldn't deduce arguments for tparms1 to make arg1 match
22494 arg2, then arg2 is not as specialized as arg1. */
22500 /* "If, for a given type, deduction succeeds in both directions
22501 (i.e., the types are identical after the transformations above)
22502 and both P and A were reference types (before being replaced with
22503 the type referred to above):
22504 - if the type from the argument template was an lvalue reference and
22505 the type from the parameter template was not, the argument type is
22506 considered to be more specialized than the other; otherwise,
22507 - if the type from the argument template is more cv-qualified
22508 than the type from the parameter template (as described above),
22509 the argument type is considered to be more specialized than the other;
22510 otherwise,
22511 - neither type is more specialized than the other." */
22514 {
22516 {
22519 else
22521 }
22523 {
22528 }
22529 }
22532 /* We've failed to deduce something in either direction.
22533 These must be unordered. */
22536 next:
22540 /* We have already processed all of the arguments in our
22541 handing of the pack expansion type. */
22546 }
22548 /* "In most cases, all template parameters must have values in order for
22549 deduction to succeed, but for partial ordering purposes a template
22550 parameter may remain without a value provided it is not used in the
22551 types being used for partial ordering."
22553 Thus, if we are missing any of the targs1 we need to substitute into
22554 origs1, then pat2 is not as specialized as pat1. This can happen when
22555 there is a nondeduced context. */
22561 processing_template_decl--;
22563 /* If both deductions succeed, the partial ordering selects the more
22564 constrained template. */
22566 {
22571 }
22573 /* All things being equal, if the next argument is a pack expansion
22574 for one function but not for the other, prefer the
22575 non-variadic function. FIXME this is bogus; see c++/41958. */
22579 {
22582 }
22588 else
22590 }
22592 /* Determine which of two partial specializations of TMPL is more
22593 specialized.
22595 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
22596 to the first partial specialization. The TREE_PURPOSE is the
22597 innermost set of template parameters for the partial
22598 specialization. PAT2 is similar, but for the second template.
22600 Return 1 if the first partial specialization is more specialized;
22601 -1 if the second is more specialized; 0 if neither is more
22602 specialized.
22604 See [temp.class.order] for information about determining which of
22605 two templates is more specialized. */
22607 static int
22609 {
22610 tree targs;
22619 /* Just like what happens for functions, if we are ordering between
22620 different template specializations, we may encounter dependent
22621 types in the arguments, and we need our dependency check functions
22622 to behave correctly. */
22626 {
22629 }
22633 {
22636 }
22639 /* If both deductions succeed, the partial ordering selects the more
22640 constrained template. */
22644 /* In the case of a tie where at least one of the templates
22645 has a parameter pack at the end, the template with the most
22646 non-packed parameters wins. */
22648 && any_deductions
22651 {
22657 /* We don't count the pack expansion at the end. */
22667 }
22670 }
22672 /* Return the template arguments that will produce the function signature
22673 DECL from the function template FN, with the explicit template
22674 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
22675 also match. Return NULL_TREE if no satisfactory arguments could be
22676 found. */
22678 static tree
22680 {
22684 tree decl_arg_types;
22687 tree arg;
22691 /* Never do unification on the 'this' parameter. */
22713 }
22715 /* Return the innermost template arguments that, when applied to a partial
22716 specialization SPEC_TMPL of TMPL, yield the ARGS.
22718 For example, suppose we have:
22720 template <class T, class U> struct S {};
22721 template <class T> struct S<T*, int> {};
22723 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
22724 partial specialization and the ARGS will be {double*, int}. The resulting
22725 vector will be {double}, indicating that `T' is bound to `double'. */
22727 static tree
22729 {
22731 tree spec_args
22734 tree deduced_args;
22735 tree innermost_deduced_args;
22739 {
22743 innermost_deduced_args);
22744 }
22745 else
22749 again:
22758 {
22760 {
22766 }
22768 }
22771 {
22774 }
22776 /* Verify that nondeduced template arguments agree with the type
22777 obtained from argument deduction.
22779 For example:
22781 struct A { typedef int X; };
22782 template <class T, class U> struct C {};
22783 template <class T> struct C<T, typename T::X> {};
22785 Then with the instantiation `C<A, int>', we can deduce that
22786 `T' is `A' but unify () does not check whether `typename T::X'
22787 is `int'. */
22798 /* We only need to check the innermost arguments; the other
22799 arguments will always agree. */
22804 /* Now that we have bindings for all of the template arguments,
22805 ensure that the arguments deduced for the template template
22806 parameters have compatible template parameter lists. See the use
22807 of template_template_parm_bindings_ok_p in fn_type_unification
22808 for more information. */
22813 }
22815 // Compare two function templates T1 and T2 by deducing bindings
22816 // from one against the other. If both deductions succeed, compare
22817 // constraints to see which is more constrained.
22818 static int
22820 {
22825 {
22828 }
22831 {
22834 }
22836 // If both deductions succeed, then one may be more constrained.
22841 }
22843 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22844 Return the TREE_LIST node with the most specialized template, if
22845 any. If there is no most specialized template, the error_mark_node
22846 is returned.
22848 Note that this function does not look at, or modify, the
22849 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22850 returned is one of the elements of INSTANTIATIONS, callers may
22851 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22852 and retrieve it from the value returned. */
22854 tree
22856 {
22863 {
22869 {
22870 /* Equally specialized, move to next function. If there
22871 is no next function, nothing's most specialized. */
22876 }
22877 }
22880 /* Now verify that champ is better than everything earlier in the
22881 instantiation list. */
22884 {
22887 }
22888 }
22890 processing_template_decl--;
22896 }
22898 /* If DECL is a specialization of some template, return the most
22899 general such template. Otherwise, returns NULL_TREE.
22901 For example, given:
22903 template <class T> struct S { template <class U> void f(U); };
22905 if TMPL is `template <class U> void S<int>::f(U)' this will return
22906 the full template. This function will not trace past partial
22907 specializations, however. For example, given in addition:
22909 template <class T> struct S<T*> { template <class U> void f(U); };
22911 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22912 `template <class T> template <class U> S<T*>::f(U)'. */
22914 tree
22916 {
22918 {
22921 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22922 template friend, or a FIELD_DECL for a capture pack. */
22925 }
22927 /* Look for more and more general templates. */
22929 {
22930 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22931 (See cp-tree.h for details.) */
22940 /* Stop if we run into an explicitly specialized class template. */
22947 }
22950 }
22952 /* Return the most specialized of the template partial specializations
22953 which can produce TARGET, a specialization of some class or variable
22954 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22955 a TEMPLATE_DECL node corresponding to the partial specialization, while
22956 the TREE_PURPOSE is the set of template arguments that must be
22957 substituted into the template pattern in order to generate TARGET.
22959 If the choice of partial specialization is ambiguous, a diagnostic
22960 is issued, and the error_mark_node is returned. If there are no
22961 partial specializations matching TARGET, then NULL_TREE is
22962 returned, indicating that the primary template should be used. */
22964 static tree
22966 {
22968 tree t;
22969 tree champ;
22976 {
22980 }
22982 {
22985 }
22987 {
22991 }
22992 else
22997 /* For determining which partial specialization to use, only the
22998 innermost args are interesting. */
23000 {
23003 }
23006 {
23007 tree spec_args;
23011 {
23012 /* Substitute in the template args from the enclosing class. */
23016 }
23023 {
23027 /* Keep the candidate only if the constraints are satisfied,
23028 or if we're not compiling with concepts. */
23031 {
23034 }
23035 }
23036 }
23046 {
23049 ;
23050 else
23051 {
23053 {
23056 {
23059 }
23060 }
23062 }
23063 }
23067 {
23070 {
23073 }
23074 }
23077 {
23084 else
23088 {
23093 }
23096 }
23099 }
23101 /* Explicitly instantiate DECL. */
23103 void
23105 {
23110 /* An error occurred, for which grokdeclarator has already issued
23111 an appropriate message. */
23114 {
23117 }
23123 {
23124 /* There is an asymmetry here in the way VAR_DECLs and
23125 FUNCTION_DECLs are handled by grokdeclarator. In the case of
23126 the latter, the DECL we get back will be marked as a
23127 template instantiation, and the appropriate
23128 DECL_TEMPLATE_INFO will be set up. This does not happen for
23129 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
23130 should handle VAR_DECLs as it currently handles
23131 FUNCTION_DECLs. */
23133 {
23136 }
23139 {
23142 }
23144 {
23149 }
23150 }
23152 {
23155 }
23156 else
23159 /* Check for various error cases. Note that if the explicit
23160 instantiation is valid the RESULT will currently be marked as an
23161 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
23162 until we get here. */
23165 {
23166 /* DR 259 [temp.spec].
23168 Both an explicit instantiation and a declaration of an explicit
23169 specialization shall not appear in a program unless the explicit
23170 instantiation follows a declaration of the explicit specialization.
23172 For a given set of template parameters, if an explicit
23173 instantiation of a template appears after a declaration of an
23174 explicit specialization for that template, the explicit
23175 instantiation has no effect. */
23177 }
23179 {
23180 /* [temp.spec]
23182 No program shall explicitly instantiate any template more
23183 than once.
23185 We check DECL_NOT_REALLY_EXTERN so as not to complain when
23186 the first instantiation was `extern' and the second is not,
23187 and EXTERN_P for the opposite case. */
23190 /* If an "extern" explicit instantiation follows an ordinary
23191 explicit instantiation, the template is instantiated. */
23194 }
23196 {
23199 }
23201 {
23204 }
23207 ;
23209 {
23212 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
23215 }
23216 else
23224 }
23226 static void
23228 {
23234 {
23237 }
23238 }
23240 /* Called from do_type_instantiation through binding_table_foreach to
23241 do recursive instantiation for the type bound in ENTRY. */
23242 static void
23244 {
23251 }
23253 /* Perform an explicit instantiation of template class T. STORAGE, if
23254 non-null, is the RID for extern, inline or static. COMPLAIN is
23255 nonzero if this is called from the parser, zero if called recursively,
23256 since the standard is unclear (as detailed below). */
23258 void
23260 {
23270 {
23271 tree tmpl =
23275 else
23278 }
23283 {
23286 t);
23288 }
23291 {
23293 {
23295 {
23298 "ISO C++ 1998 forbids the use of %<extern%> on "
23300 }
23301 else
23303 "ISO C++ forbids the use of %qE"
23305 }
23313 else
23314 {
23316 storage);
23318 }
23319 }
23322 {
23323 /* DR 259 [temp.spec].
23325 Both an explicit instantiation and a declaration of an explicit
23326 specialization shall not appear in a program unless the explicit
23327 instantiation follows a declaration of the explicit specialization.
23329 For a given set of template parameters, if an explicit
23330 instantiation of a template appears after a declaration of an
23331 explicit specialization for that template, the explicit
23332 instantiation has no effect. */
23334 }
23336 {
23337 /* [temp.spec]
23339 No program shall explicitly instantiate any template more
23340 than once.
23342 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
23343 instantiation was `extern'. If EXTERN_P then the second is.
23344 These cases are OK. */
23351 /* If we've already instantiated the template, just return now. */
23354 }
23362 /* In contrast to implicit instantiation, where only the
23363 declarations, and not the definitions, of members are
23364 instantiated, we have here:
23366 [temp.explicit]
23368 The explicit instantiation of a class template specialization
23369 implies the instantiation of all of its members not
23370 previously explicitly specialized in the translation unit
23371 containing the explicit instantiation.
23373 Of course, we can't instantiate member template classes, since we
23374 don't have any arguments for them. Note that the standard is
23375 unclear on whether the instantiation of the members are
23376 *explicit* instantiations or not. However, the most natural
23377 interpretation is that it should be an explicit
23378 instantiation. */
23382 && !static_p
23385 {
23390 }
23395 }
23397 /* Given a function DECL, which is a specialization of TMPL, modify
23398 DECL to be a re-instantiation of TMPL with the same template
23399 arguments. TMPL should be the template into which tsubst'ing
23400 should occur for DECL, not the most general template.
23402 One reason for doing this is a scenario like this:
23404 template <class T>
23405 void f(const T&, int i);
23407 void g() { f(3, 7); }
23409 template <class T>
23410 void f(const T& t, const int i) { }
23412 Note that when the template is first instantiated, with
23413 instantiate_template, the resulting DECL will have no name for the
23414 first parameter, and the wrong type for the second. So, when we go
23415 to instantiate the DECL, we regenerate it. */
23417 static void
23419 {
23420 /* The arguments used to instantiate DECL, from the most general
23421 template. */
23422 tree code_pattern;
23426 /* Make sure that we can see identifiers, and compute access
23427 correctly. */
23431 {
23432 tree decl_parm;
23433 tree pattern_parm;
23434 tree specs;
23448 specs);
23450 /* Merge parameter declarations. */
23453 pattern_parm
23457 {
23458 tree parm_type;
23459 tree attributes;
23464 NULL_TREE);
23470 {
23473 }
23476 }
23477 /* Merge any parameters that match with the function parameter
23478 pack. */
23480 {
23482 tree expanded_types;
23483 /* Expand the TYPE_PACK_EXPANSION that provides the types for
23484 the parameters in this function parameter pack. */
23489 {
23490 tree parm_type;
23491 tree attributes;
23494 /* Rename the parameter to include the index. */
23503 {
23506 }
23508 }
23509 }
23510 /* Merge additional specifiers from the CODE_PATTERN. */
23514 }
23516 {
23526 }
23527 else
23531 }
23533 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
23534 substituted to get DECL. */
23536 tree
23538 {
23541 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
23542 for the instantiation. This is not always the most general
23543 template. Consider, for example:
23545 template <class T>
23546 struct S { template <class U> void f();
23547 template <> void f<int>(); };
23549 and an instantiation of S<double>::f<int>. We want TD to be the
23550 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
23552 more general template. */
23554 /* We must also deal with friend templates. Given:
23556 template <class T> struct S {
23557 template <class U> friend void f() {};
23558 };
23560 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
23561 so far as the language is concerned, but that's still
23562 where we get the pattern for the instantiation from. On
23563 other hand, if the definition comes outside the class, say:
23565 template <class T> struct S {
23566 template <class U> friend void f();
23567 };
23568 template <class U> friend void f() {}
23570 we don't need to look any further. That's what the check for
23571 DECL_INITIAL is for. */
23575 {
23576 /* The present template, TD, should not be a definition. If it
23577 were a definition, we should be using it! Note that we
23578 cannot restructure the loop to just keep going until we find
23579 a template with a definition, since that might go too far if
23580 a specialization was declared, but not defined. */
23582 /* Fetch the more general template. */
23584 }
23587 }
23589 /* Returns true if we need to instantiate this template instance even if we
23590 know we aren't going to emit it. */
23592 bool
23594 {
23595 /* We always instantiate inline functions so that we can inline them. An
23596 explicit instantiation declaration prohibits implicit instantiation of
23597 non-inline functions. With high levels of optimization, we would
23598 normally inline non-inline functions -- but we're not allowed to do
23599 that for "extern template" functions. Therefore, we check
23600 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
23604 /* And we need to instantiate static data members so that
23605 their initializers are available in integral constant
23606 expressions. */
23609 }
23611 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
23612 instantiate it now, modifying TREE_TYPE (fn). Returns false on
23613 error, true otherwise. */
23615 bool
23617 {
23620 /* Don't instantiate a noexcept-specification from template context. */
23636 {
23642 {
23643 /* If hash_set::add returns true, the element was already there. */
23648 fn);
23650 }
23652 {
23667 }
23668 else
23678 }
23681 {
23684 else
23686 }
23689 }
23691 /* We're starting to process the function INST, an instantiation of PATTERN;
23692 add their parameters to local_specializations. */
23694 static void
23696 {
23700 {
23704 }
23706 {
23708 {
23711 }
23712 else
23713 {
23714 /* Register the (value) argument pack as a specialization of
23715 TMPL_PARM, then move on. */
23718 }
23719 }
23721 }
23723 /* Produce the definition of D, a _DECL generated from a template. If
23724 DEFER_OK is true, then we don't have to actually do the
23725 instantiation now; we just have to do it sometime. Normally it is
23726 an error if this is an explicit instantiation but D is undefined.
23727 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
23728 instantiated class template. */
23730 tree
23732 {
23734 tree gen_args;
23735 tree args;
23736 tree td;
23737 tree code_pattern;
23738 tree spec;
23739 tree gen_tmpl;
23747 /* This function should only be used to instantiate templates for
23748 functions and static member variables. */
23751 /* A concept is never instantiated. */
23754 /* Variables are never deferred; if instantiation is required, they
23755 are instantiated right away. That allows for better code in the
23756 case that an expression refers to the value of the variable --
23757 if the variable has a constant value the referring expression can
23758 take advantage of that fact. */
23762 /* Don't instantiate cloned functions. Instead, instantiate the
23763 functions they cloned. */
23771 /* D has already been instantiated or explicitly specialized, so
23772 there's nothing for us to do here.
23774 It might seem reasonable to check whether or not D is an explicit
23775 instantiation, and, if so, stop here. But when an explicit
23776 instantiation is deferred until the end of the compilation,
23777 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
23778 the instantiation. */
23781 /* Check to see whether we know that this template will be
23782 instantiated in some other file, as with "extern template"
23783 extension. */
23786 /* In general, we do not instantiate such templates. */
23794 /* We should already have the extra args. */
23797 /* And what's in the hash table should match D. */
23801 /* This needs to happen before any tsubsting. */
23807 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23808 for the instantiation. */
23813 {
23814 /* Look up an explicit specialization, if any. */
23818 {
23821 }
23822 }
23826 /* We should never be trying to instantiate a member of a class
23827 template or partial specialization. */
23832 /* In the case of a friend template whose definition is provided
23833 outside the class, we may have too many arguments. Drop the
23834 ones we don't need. The same is true for specializations. */
23835 args = get_innermost_template_args
23839 {
23845 }
23846 else
23847 {
23852 else
23854 }
23856 /* We may be in the middle of deferred access check. Disable it now. */
23859 /* Unless an explicit instantiation directive has already determined
23860 the linkage of D, remember that a definition is available for
23861 this entity. */
23871 /* If D is a member of an explicitly instantiated class template,
23872 and no definition is available, treat it like an implicit
23873 instantiation. */
23876 {
23877 /* Leave linkage flags alone on instantiations with anonymous
23878 visibility. */
23880 {
23883 }
23885 }
23887 /* Defer all other templates, unless we have been explicitly
23888 forbidden from doing so. */
23890 template. */
23891 ! pattern_defined
23892 /* If it's OK to postpone instantiation, do so. */
23893 || defer_ok
23894 /* If this is a static data member that will be defined
23895 elsewhere, we don't want to instantiate the entire data
23896 member, but we do want to instantiate the initializer so that
23897 we can substitute that elsewhere. */
23899 /* Handle here a deleted function too, avoid generating
23900 its body (c++/61080). */
23902 {
23903 /* The definition of the static data member is now required so
23904 we must substitute the initializer. */
23908 {
23909 tree ns;
23910 tree init;
23919 args,
23922 /* If instantiating the initializer involved instantiating this
23923 again, don't call cp_finish_decl twice. */
23925 {
23926 /* Make sure the initializer is still constant, in case of
23927 circular dependency (template/instantiate6.C). */
23928 const_init
23932 LOOKUP_ONLYCONVERTING);
23933 }
23937 }
23939 /* We restore the source position here because it's used by
23940 add_pending_template. */
23946 /* [temp.explicit]
23948 The definition of a non-exported function template, a
23949 non-exported member function template, or a non-exported
23950 member function or static data member of a class template
23951 shall be present in every translation unit in which it is
23952 explicitly instantiated. */
23956 /* If we're in unevaluated context, we just wanted to get the
23957 constant value; this isn't an odr use, so don't queue
23958 a full instantiation. */
23961 /* ??? Historically, we have instantiated inline functions, even
23962 when marked as "extern template". */
23966 }
23967 /* Tell the repository that D is available in this translation unit
23968 -- and see if it is supposed to be instantiated here. */
23970 {
23971 /* In a PCH file, despite the fact that the repository hasn't
23972 requested instantiation in the PCH it is still possible that
23973 an instantiation will be required in a file that includes the
23974 PCH. */
23977 /* Instantiate inline functions so that the inliner can do its
23978 job, even though we'll not be emitting a copy of this
23979 function. */
23982 }
23985 tree fn_context;
23988 /* tsubst_lambda_expr resolved any references to enclosing functions. */
23999 else
24000 {
24005 }
24007 /* Mark D as instantiated so that recursive calls to
24008 instantiate_decl do not try to instantiate it again. */
24011 /* Regenerate the declaration in case the template has been modified
24012 by a subsequent redeclaration. */
24015 /* We already set the file and line above. Reset them now in case
24016 they changed as a result of calling regenerate_decl_from_template. */
24020 {
24021 tree init;
24024 /* Clear out DECL_RTL; whatever was there before may not be right
24025 since we've reset the type of the declaration. */
24029 /* The initializer is placed in DECL_INITIAL by
24030 regenerate_decl_from_template so we don't need to
24031 push/pop_access_scope again here. Pull it out so that
24032 cp_finish_decl can process it. */
24037 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
24038 initializer. That function will defer actual emission until
24039 we have a chance to determine linkage. */
24042 /* Enter the scope of D so that access-checking works correctly. */
24055 }
24059 {
24060 /* Set up the list of local specializations. */
24064 /* Set up context. */
24068 else
24071 /* Some typedefs referenced from within the template code need to be
24072 access checked at template instantiation time, i.e now. These
24073 types were added to the template at parsing time. Let's get those
24074 and perform the access checks then. */
24076 args);
24078 /* Create substitution entries for the parameters. */
24081 /* Substitute into the body of the function. */
24085 else
24086 {
24091 /* Set the current input_location to the end of the function
24092 so that finish_function knows where we are. */
24093 input_location
24096 /* Remember if we saw an infinite loop in the template. */
24097 current_function_infinite_loop
24099 }
24101 /* Finish the function. */
24105 else
24106 {
24109 }
24113 }
24115 /* We're not deferring instantiation any more. */
24120 else
24126 out:
24135 }
24137 /* Run through the list of templates that we wish we could
24138 instantiate, and instantiate any we can. RETRIES is the
24139 number of times we retry pending template instantiation. */
24141 void
24143 {
24147 /* Instantiating templates may trigger vtable generation. This in turn
24148 may require further template instantiations. We place a limit here
24149 to avoid infinite loop. */
24151 {
24155 "template instantiation depth exceeds maximum of %d"
24156 " instantiating %q+D, possibly from virtual table generation"
24160 /* Pretend that we defined it. */
24163 }
24165 do
24166 {
24171 {
24176 {
24178 {
24193 }
24196 }
24197 else
24198 {
24201 {
24202 instantiation
24208 }
24212 }
24215 {
24216 /* If INSTANTIATION has been instantiated, then we don't
24217 need to consider it again in the future. */
24222 }
24223 else
24224 {
24227 }
24230 }
24232 }
24236 }
24238 /* Substitute ARGVEC into T, which is a list of initializers for
24239 either base class or a non-static data member. The TREE_PURPOSEs
24240 are DECLs, and the TREE_VALUEs are the initializer values. Used by
24241 instantiate_decl. */
24243 static tree
24245 {
24250 {
24251 tree decl;
24252 tree init;
24258 {
24259 tree expr;
24260 tree arg;
24262 /* Expand the base class expansion type into separate base
24263 classes. */
24265 tf_warning_or_error,
24266 NULL_TREE);
24270 /* We'll be building separate TREE_LISTs of arguments for
24271 each base. */
24277 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
24278 expand each argument in the TREE_VALUE of t. */
24285 /* VOID_TYPE_NODE is used to indicate
24286 value-initialization. */
24287 {
24290 }
24291 else
24292 {
24293 /* Substitute parameter packs into each argument in the
24294 TREE_LIST. */
24297 {
24298 tree expanded_exprs;
24300 /* Expand the argument. */
24302 expanded_exprs
24304 tf_warning_or_error,
24305 NULL_TREE);
24309 /* Prepend each of the expanded expressions to the
24310 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
24312 {
24317 }
24318 }
24321 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
24322 since we built them backwards. */
24324 {
24327 }
24328 }
24329 }
24332 {
24334 {
24338 }
24339 else
24340 {
24341 tree tmp;
24356 /* If we had an initializer but it instantiated to nothing,
24357 value-initialize the object. This will only occur when
24358 the initializer was a pack expansion where the parameter
24359 packs used in that expansion were of length zero. */
24362 }
24366 {
24368 decl);
24370 }
24371 /* Look for a target constructor. */
24375 {
24378 {
24382 }
24384 }
24387 {
24391 }
24392 }
24393 }
24395 }
24397 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
24399 static void
24401 {
24406 else
24408 }
24410 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
24411 is the instantiation (which should have been created with
24412 start_enum) and ARGS are the template arguments to use. */
24414 static void
24416 {
24417 tree e;
24423 {
24424 tree value;
24425 tree decl;
24428 /* Note that in a template enum, the TREE_VALUE is the
24429 CONST_DECL, not the corresponding INTEGER_CST. */
24434 /* Give this enumeration constant the correct access. */
24437 /* Actually build the enumerator itself. Here we're assuming that
24438 enumerators can't have dependent attributes. */
24441 }
24451 }
24453 /* DECL is a FUNCTION_DECL that is a template specialization. Return
24454 its type -- but without substituting the innermost set of template
24455 arguments. So, innermost set of template parameters will appear in
24456 the type. */
24458 tree
24460 {
24461 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
24463 }
24465 /* Return truthvalue if we're processing a template different from
24466 the last one involved in diagnostics. */
24467 bool
24469 {
24471 }
24473 /* Remember current template involved in diagnostics. */
24474 void
24476 {
24478 }
24482 {
24484 }
24486 /* Return TRUE if current_function_decl is being instantiated, false
24487 otherwise. */
24489 bool
24491 {
24495 }
24497 /* [temp.param] Check that template non-type parm TYPE is of an allowable
24498 type. Return false for ok, true for disallowed. Issue error and
24499 inform messages under control of COMPLAIN. */
24501 static bool
24503 {
24521 /* A bound template template parm could later be instantiated to have a valid
24522 nontype parm type via an alias template. */
24528 {
24531 else
24533 type);
24534 }
24536 }
24538 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
24539 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
24541 static bool
24543 {
24544 tree scope;
24546 /* [temp.dep.type]
24548 A type is dependent if it is:
24550 -- a template parameter. Template template parameters are types
24551 for us (since TYPE_P holds true for them) so we handle
24552 them here. */
24556 /* -- a qualified-id with a nested-name-specifier which contains a
24557 class-name that names a dependent type or whose unqualified-id
24558 names a dependent type. */
24562 /* An alias template specialization can be dependent even if the
24563 resulting type is not. */
24567 /* -- a cv-qualified type where the cv-unqualified type is
24568 dependent.
24569 No code is necessary for this bullet; the code below handles
24570 cv-qualified types, and we don't want to strip aliases with
24571 TYPE_MAIN_VARIANT because of DR 1558. */
24572 /* -- a compound type constructed from any dependent type. */
24581 {
24582 tree arg_type;
24587 arg_type;
24592 /* A value-dependent noexcept-specifier makes the type dependent. */
24595 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
24596 affect overload resolution and treating it as dependent breaks
24597 things. */
24602 }
24603 /* -- an array type constructed from any dependent type or whose
24604 size is specified by a constant expression that is
24605 value-dependent.
24607 We checked for type- and value-dependence of the bounds in
24608 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
24610 {
24615 }
24617 /* -- a template-id in which either the template name is a template
24618 parameter ... */
24621 /* ... or any of the template arguments is a dependent type or
24622 an expression that is type-dependent or value-dependent. */
24624 && (any_dependent_template_arguments_p
24628 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
24629 dependent; if the argument of the `typeof' expression is not
24630 type-dependent, then it should already been have resolved. */
24636 /* A template argument pack is dependent if any of its packed
24637 arguments are. */
24639 {
24645 }
24647 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
24648 be template parameters. */
24655 /* The standard does not specifically mention types that are local
24656 to template functions or local classes, but they should be
24657 considered dependent too. For example:
24659 template <int I> void f() {
24660 enum E { a = I };
24661 S<sizeof (E)> s;
24662 }
24664 The size of `E' cannot be known until the value of `I' has been
24665 determined. Therefore, `E' must be considered dependent. */
24669 /* Don't use type_dependent_expression_p here, as it can lead
24670 to infinite recursion trying to determine whether a lambda
24671 nested in a lambda is dependent (c++/47687). */
24675 && (any_dependent_template_arguments_p
24679 /* Other types are non-dependent. */
24681 }
24683 /* Returns TRUE if TYPE is dependent, in the sense of
24684 [temp.dep.type]. Note that a NULL type is considered dependent. */
24686 bool
24688 {
24689 /* If there are no template parameters in scope, then there can't be
24690 any dependent types. */
24692 {
24693 /* If we are not processing a template, then nobody should be
24694 providing us with a dependent type. */
24698 }
24700 /* If the type is NULL, we have not computed a type for the entity
24701 in question; in that case, the type is dependent. */
24705 /* Erroneous types can be considered non-dependent. */
24709 /* Getting here with global_type_node means we improperly called this
24710 function on the TREE_TYPE of an IDENTIFIER_NODE. */
24713 /* If we have not already computed the appropriate value for TYPE,
24714 do so now. */
24716 {
24719 }
24722 }
24724 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
24725 lookup. In other words, a dependent type that is not the current
24726 instantiation. */
24728 bool
24730 {
24733 }
24735 /* T is a SCOPE_REF. Return whether it represents a non-static member of
24736 an unknown base of 'this' (and is therefore instantiation-dependent). */
24738 static bool
24740 {
24757 }
24759 /* T is a SCOPE_REF; return whether we need to consider it
24760 instantiation-dependent so that we can check access at instantiation
24761 time even though we know which member it resolves to. */
24763 static bool
24765 {
24772 else
24774 }
24776 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
24777 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
24778 expression. */
24780 /* Note that this predicate is not appropriate for general expressions;
24781 only constant expressions (that satisfy potential_constant_expression)
24782 can be tested for value dependence. */
24784 bool
24786 {
24790 /* A type-dependent expression is also value-dependent. */
24795 {
24797 /* A dependent member function of the current instantiation. */
24801 /* A dependent member function of the current instantiation. */
24808 /* A name that has not been looked up -- must be dependent. */
24812 /* A non-type template parm. */
24816 /* A non-type template parm. */
24822 /* A constant with literal type and is initialized
24823 with an expression that is value-dependent. */
24825 /* FIXME cp_finish_decl doesn't fold reference initializers. */
24829 {
24833 }
24842 /* These expressions are value-dependent if the type to which
24843 the cast occurs is dependent or the expression being casted
24844 is value-dependent. */
24845 {
24851 /* A functional cast has a list of operands. */
24854 {
24855 /* If there are no operands, it must be an expression such
24856 as "int()". This should not happen for aggregate types
24857 because it would form non-constant expressions. */
24862 }
24868 }
24873 /* FALLTHRU */
24876 /* A `sizeof' expression is value-dependent if the operand is
24877 type-dependent or is a pack expansion. */
24886 /* An 'encode' expression is value-dependent if the operand is
24887 type-dependent. */
24896 /* All instantiation-dependent expressions should also be considered
24897 value-dependent. */
24905 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24906 is value-dependent. */
24907 {
24916 }
24919 {
24936 }
24947 {
24951 }
24954 /* Treat all requires-expressions as value-dependent so
24955 we don't try to fold them. */
24962 {
24969 {
24971 /* In a call to a constexpr member function, look through the
24972 implicit ADDR_EXPR on the object argument so that it doesn't
24973 cause the call to be considered value-dependent. We also
24974 look through it in potential_constant_expression. */
24981 }
24983 }
24989 {
24991 tree val;
24998 }
25001 /* Treat a GNU statement expression as dependent to avoid crashing
25002 under instantiate_non_dependent_expr; it can't be constant. */
25006 /* A constant expression is value-dependent if any subexpression is
25007 value-dependent. */
25009 {
25016 {
25020 {
25023 /* In some cases, some of the operands may be missing.
25024 (For example, in the case of PREDECREMENT_EXPR, the
25025 amount to increment by may be missing.) That doesn't
25026 make the expression dependent. */
25029 }
25030 }
25034 }
25036 }
25038 /* The expression is not value-dependent. */
25040 }
25042 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
25043 [temp.dep.expr]. Note that an expression with no type is
25044 considered dependent. Other parts of the compiler arrange for an
25045 expression with type-dependent subexpressions to have no type, so
25046 this function doesn't have to be fully recursive. */
25048 bool
25050 {
25059 /* An unresolved name is always dependent. */
25065 /* A fold expression is type-dependent. */
25072 /* Some expression forms are never type-dependent. */
25086 /* The types of these expressions depends only on the type to which
25087 the cast occurs. */
25096 /* The types of these expressions depends only on the type created
25097 by the expression. */
25100 {
25101 /* For NEW_EXPR tree nodes created inside a template, either
25102 the object type itself or a TREE_LIST may appear as the
25103 operand 1. */
25106 /* This is an array type. We need to check array dimensions
25107 as well. */
25109 || value_dependent_expression_p
25111 else
25113 }
25116 {
25120 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
25121 contains an identifier associated by name lookup with one or more
25122 declarations declared with a dependent type, or...a
25123 nested-name-specifier or qualified-id that names a member of an
25124 unknown specialization. */
25127 }
25137 {
25138 tree elt;
25142 {
25145 }
25147 }
25149 /* A static data member of the current instantiation with incomplete
25150 array type is type-dependent, as the definition and specializations
25151 can have different bounds. */
25158 /* An array of unknown bound depending on a variadic parameter, eg:
25160 template<typename... Args>
25161 void foo (Args... args)
25162 {
25163 int arr[] = { args... };
25164 }
25166 template<int... vals>
25167 void bar ()
25168 {
25169 int arr[] = { vals... };
25170 }
25172 If the array has no length and has an initializer, it must be that
25173 we couldn't determine its length in cp_complete_array_type because
25174 it is dependent. */
25182 /* A function or variable template-id is type-dependent if it has any
25183 dependent template arguments. */
25187 {
25188 /* Consider the innermost template arguments, since those are the ones
25189 that come from the template-id; the template arguments for the
25190 enclosing class do not make it type-dependent unless they are used in
25191 the type of the decl. */
25193 && (any_dependent_template_arguments_p
25196 }
25198 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
25199 type-dependent. Checking this is important for functions with auto return
25200 type, which looks like a dependent type. */
25209 {
25213 }
25215 /* Always dependent, on the number of arguments if nothing else. */
25220 {
25225 {
25231 }
25232 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
25237 {
25242 }
25245 {
25252 }
25262 }
25266 /* Dependent type attributes might not have made it from the decl to
25267 the type yet. */
25273 }
25275 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
25276 type-dependent if the expression refers to a member of the current
25277 instantiation and the type of the referenced member is dependent, or the
25278 class member access expression refers to a member of an unknown
25279 specialization.
25281 This function returns true if the OBJECT in such a class member access
25282 expression is of an unknown specialization. */
25284 bool
25286 {
25287 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
25288 dependent. */
25293 }
25295 /* walk_tree callback function for instantiation_dependent_expression_p,
25296 below. Returns non-zero if a dependent subexpression is found. */
25298 static tree
25301 {
25303 {
25304 /* We don't have to worry about decltype currently because decltype
25305 of an instantiation-dependent expr is a dependent type. This
25306 might change depending on the resolution of DR 1172. */
25309 }
25312 {
25313 /* Don't treat an argument list as dependent just because it has no
25314 TREE_TYPE. */
25323 /* Handle expressions with type operands. */
25328 {
25333 {
25336 else
25337 {
25340 }
25341 }
25343 }
25347 /* In a template, finish_class_member_access_expr creates a
25348 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
25349 type-dependent, so that we can check access control at
25350 instantiation time (PR 42277). See also Core issue 1273. */
25357 else
25360 /* Treat statement-expressions as dependent. */
25364 /* Treat requires-expressions as dependent. */
25369 /* Treat calls to function concepts as dependent. */
25375 /* And variable concepts. */
25382 }
25386 else
25388 }
25390 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
25391 sense defined by the ABI:
25393 "An expression is instantiation-dependent if it is type-dependent
25394 or value-dependent, or it has a subexpression that is type-dependent
25395 or value-dependent."
25397 Except don't actually check value-dependence for unevaluated expressions,
25398 because in sizeof(i) we don't care about the value of i. Checking
25399 type-dependence will in turn check value-dependence of array bounds/template
25400 arguments as needed. */
25402 bool
25404 {
25405 tree result;
25416 }
25418 /* As above, but also check value-dependence of the expression as a whole. */
25420 bool
25422 {
25425 }
25427 /* Like type_dependent_expression_p, but it also works while not processing
25428 a template definition, i.e. during substitution or mangling. */
25430 bool
25432 {
25438 }
25440 /* Returns TRUE if ARGS contains a type-dependent expression. */
25442 bool
25444 {
25446 tree arg;
25449 {
25452 }
25454 }
25456 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25457 expressions) contains any type-dependent expressions. */
25459 bool
25461 {
25467 }
25469 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
25470 expressions) contains any value-dependent expressions. */
25472 bool
25474 {
25480 }
25482 /* Returns TRUE if the ARG (a template argument) is dependent. */
25484 bool
25486 {
25490 /* Assume a template argument that was wrongly written by the user
25491 is dependent. This is consistent with what
25492 any_dependent_template_arguments_p [that calls this function]
25493 does. */
25503 {
25506 /* A member template of a dependent class is not necessarily
25507 type-dependent, but it is a dependent template argument because it
25508 will be a member of an unknown specialization to that template. */
25511 }
25513 {
25517 {
25520 }
25523 }
25526 else
25529 }
25531 /* Returns true if ARGS (a collection of template arguments) contains
25532 any types that require structural equality testing. */
25534 bool
25536 {
25546 {
25549 {
25555 {
25556 /* Look inside the argument pack. */
25559 }
25562 {
25575 }
25576 }
25577 }
25580 }
25582 /* Returns true if ARGS (a collection of template arguments) contains
25583 any dependent arguments. */
25585 bool
25587 {
25597 {
25602 }
25605 }
25607 /* Returns true if ARGS contains any errors. */
25609 bool
25611 {
25619 {
25622 else
25624 }
25630 {
25635 }
25638 }
25640 /* Returns TRUE if the template TMPL is type-dependent. */
25642 bool
25644 {
25646 {
25651 }
25653 /* Template template parameters are dependent. */
25657 /* So are names that have not been looked up. */
25661 }
25663 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
25665 bool
25667 {
25670 }
25672 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
25673 are dependent. */
25675 bool
25677 {
25684 {
25706 {
25710 }
25714 {
25718 {
25723 }
25724 }
25725 }
25728 }
25730 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
25731 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
25732 no such TYPE can be found. Note that this function peers inside
25733 uninstantiated templates and therefore should be used only in
25734 extremely limited situations. ONLY_CURRENT_P restricts this
25735 peering to the currently open classes hierarchy (which is required
25736 when comparing types). */
25738 tree
25740 {
25741 tree scope;
25742 tree name;
25743 tree decl;
25745 tree pushed_scope;
25746 tree result;
25751 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
25754 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
25755 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
25756 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
25757 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
25758 identifier of the TYPENAME_TYPE anymore.
25759 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
25760 TYPENAME_TYPE instead, we avoid messing up with a possible
25761 typedef variant case. */
25764 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
25765 it first before we can figure out what NAME refers to. */
25767 {
25769 /* Given a class template A with a dependent base with nested type C,
25770 typedef typename A::C::C C will land us here, as trying to resolve
25771 the initial A::C leads to the local C typedef, which leads back to
25772 A::C::C. So we break the recursion now. */
25774 else
25776 }
25777 /* If we don't know what SCOPE refers to, then we cannot resolve the
25778 TYPENAME_TYPE. */
25781 /* If this is a typedef, we don't want to look inside (c++/11987). */
25784 /* If SCOPE isn't the template itself, it will not have a valid
25785 TYPE_FIELDS list. */
25787 /* scope is either the template itself or a compatible instantiation
25788 like X<T>, so look up the name in the original template. */
25790 /* If scope has no fields, it can't be a current instantiation. Check this
25791 before currently_open_class to avoid infinite recursion (71515). */
25794 /* If the SCOPE is not the current instantiation, there's no reason
25795 to look inside it. */
25798 /* Enter the SCOPE so that name lookup will be resolved as if we
25799 were in the class definition. In particular, SCOPE will no
25800 longer be considered a dependent type. */
25802 /* Look up the declaration. */
25804 tf_warning_or_error);
25808 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
25809 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
25815 {
25819 }
25822 {
25823 /* Obtain the template and the arguments. */
25826 {
25827 /* We get here with a plain identifier because a previous tentative
25828 parse of the nested-name-specifier as part of a ptr-operator saw
25829 ::template X<A>. The use of ::template is necessary in a
25830 ptr-operator, but wrong in a declarator-id.
25832 [temp.names]: In a qualified-id of a declarator-id, the keyword
25833 template shall not appear at the top level. */
25837 }
25839 /* Instantiate the template. */
25845 }
25847 /* Leave the SCOPE. */
25851 /* If we failed to resolve it, return the original typename. */
25855 /* If lookup found a typename type, resolve that too. */
25857 {
25858 /* Ill-formed programs can cause infinite recursion here, so we
25859 must catch that. */
25863 }
25865 /* Qualify the resulting type. */
25871 }
25873 /* EXPR is an expression which is not type-dependent. Return a proxy
25874 for EXPR that can be used to compute the types of larger
25875 expressions containing EXPR. */
25877 tree
25879 {
25881 tree inner_expr;
25883 /* When checking, try to get a constant value for all non-dependent
25884 expressions in order to expose bugs in *_dependent_expression_p
25885 and constexpr. This can affect code generation, see PR70704, so
25886 only do this for -fchecking=2. */
25889 /* Don't do this during nsdmi parsing as it can lead to
25890 unexpected recursive instantiations. */
25892 /* Don't do this during concept expansion either and for
25893 the same reason. */
25899 /* Preserve OVERLOADs; the functions must be available to resolve
25900 types. */
25911 /* There is no need to return a proxy for a variable or enumerator. */
25914 /* Preserve string constants; conversions from string constants to
25915 "char *" are allowed, even though normally a "const char *"
25916 cannot be used to initialize a "char *". */
25919 /* Preserve void and arithmetic constants, as an optimization -- there is no
25920 reason to create a new node. */
25925 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25926 There is at least one place where we want to know that a
25927 particular expression is a throw-expression: when checking a ?:
25928 expression, there are special rules if the second or third
25929 argument is a throw-expression. */
25933 /* Don't wrap an initializer list, we need to be able to look inside. */
25937 /* Don't wrap a dummy object, we need to be able to test for it. */
25956 /* If the type is unknown, it can't really be non-dependent */
25959 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25962 }
25964 /* ARGS is a vector of expressions as arguments to a function call.
25965 Replace the arguments with equivalent non-dependent expressions.
25966 This modifies ARGS in place. */
25968 void
25970 {
25972 tree arg;
25975 {
25979 }
25980 }
25982 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25983 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25984 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25986 static tree
25988 {
26002 }
26004 tree
26006 {
26008 }
26010 tree
26012 {
26014 }
26016 /* Return a C++17 deduction placeholder for class template TMPL. */
26018 tree
26020 {
26024 }
26026 /* True iff T is a C++17 class template deduction placeholder. */
26028 bool
26030 {
26032 }
26034 /* Make a "constrained auto" type-specifier. This is an
26035 auto type with constraints that must be associated after
26036 deduction. The constraint is formed from the given
26037 CONC and its optional sequence of arguments, which are
26038 non-null if written as partial-concept-id. */
26040 tree
26042 {
26045 /* Build the constraint. */
26053 /* Our canonical type depends on the constraint. */
26056 /* Attach the constraint to the type declaration. */
26059 }
26061 /* Given type ARG, return std::initializer_list<ARG>. */
26063 static tree
26065 {
26069 {
26073 "deducing from brace-enclosed initializer list"
26077 }
26083 }
26085 /* Replace auto in TYPE with std::initializer_list<auto>. */
26087 static tree
26089 {
26096 }
26098 /* Hash traits for hashing possibly constrained 'auto'
26099 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
26102 {
26105 };
26107 /* Hash the 'auto' T. */
26109 inline hashval_t
26111 {
26113 /* Matching constrained-type-specifiers denote the same template
26114 parameter, so hash the constraint. */
26116 else
26117 /* But unconstrained autos are all separate, so just hash the pointer. */
26119 }
26121 /* Compare two 'auto's. */
26125 {
26132 /* Two unconstrained autos are distinct. */
26137 }
26139 /* for_each_template_parm callback for extract_autos: if t is a (possibly
26140 constrained) auto, add it to the vector. */
26142 static int
26144 {
26147 {
26148 /* All the autos were built with index 0; fix that up now. */
26152 /* If this is a repeated constrained-type-specifier, use the index we
26153 chose before. */
26155 else
26156 {
26157 /* Otherwise this is new, so use the current count. */
26160 }
26162 }
26164 /* Always keep walking. */
26166 }
26168 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
26169 says they can appear anywhere in the type. */
26171 static tree
26173 {
26182 {
26187 }
26190 }
26192 /* The stem for deduction guide names. */
26195 /* Return the name for a deduction guide for class template TMPL. */
26197 tree
26199 {
26210 }
26212 /* True if NAME is the name of a deduction guide. */
26214 bool
26216 {
26221 }
26223 /* True if FN is a deduction guide. */
26225 bool
26227 {
26232 }
26234 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
26236 bool
26238 {
26245 }
26247 /* True if FN is a guide generated from a constructor template. */
26249 bool
26251 {
26259 }
26261 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
26262 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
26263 template parameter types. Note that the handling of template template
26264 parameters relies on current_template_parms being set appropriately for the
26265 new template. */
26267 static tree
26270 {
26276 tree newtype;
26279 {
26286 }
26287 else
26288 {
26291 {
26292 // Substitute once to fix references to other template parameters.
26295 // Now substitute again to reduce the level of the auto.
26298 }
26299 else
26302 }
26304 tree newdecl
26309 tree newidx;
26312 {
26322 {
26327 // First create a copy (ttargs) of tsubst_args with an
26328 // additional level for the template template parameter's own
26329 // template parameters (ttparms).
26330 tree ttparms = (INNERMOST_TEMPLATE_PARMS
26338 // Substitute ttargs into ttparms to fix references to
26339 // other template parameters.
26342 // Now substitute again with args based on tparms, to reduce
26343 // the level of the ttparms.
26346 complain);
26347 // Finally, tack the adjusted parms onto tparms.
26349 current_template_parms);
26351 }
26352 }
26353 else
26354 {
26356 tree newconst
26368 }
26371 }
26373 /* Returns a C++17 class deduction guide template based on the constructor
26374 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
26375 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
26377 static tree
26379 {
26383 location_t loc;
26387 {
26391 {
26394 }
26395 else
26405 }
26406 else
26407 {
26411 fn_tmpl
26421 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
26422 fully specialized args for the enclosing class. Strip those off, as
26423 the deduction guide won't have those template parameters. */
26426 /* Discard the 'this' parameter. */
26434 {
26437 /* For a member template constructor, we need to flatten the two
26438 template parameter lists into one, and then adjust the function
26439 signature accordingly. This gets...complicated. */
26442 /* For a member template we should have two levels of parms/args, one
26443 for the class and one for the constructor. We stripped
26444 specialized args for further enclosing classes above. */
26448 /* Template args for translating references to the two-level template
26449 parameters into references to the one-level template parameters we
26450 are creating. */
26455 /* Template parms for the constructor template. */
26458 /* Template parms for the class template. */
26462 /* Template parms for the deduction guide start as a copy of the
26463 template parms for the class. We set current_template_parms for
26464 lookup_template_class_1. */
26470 /* Now we need to rewrite the constructor parms to append them to the
26471 class parms. */
26473 {
26490 }
26492 /* Now we have a final set of template parms to substitute into the
26493 function signature. */
26502 }
26507 }
26510 {
26511 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
26515 }
26519 FUNCTION_DECL,
26536 }
26538 /* Deduce template arguments for the class template placeholder PTYPE for
26539 template TMPL based on the initializer INIT, and return the resulting
26540 type. */
26542 static tree
26544 tsubst_flags_t complain)
26545 {
26547 {
26548 /* We should have handled this in the caller. */
26554 }
26565 {
26568 {
26569 /* As an exception, the first phase in 16.3.1.7 (considering the
26570 initializer list as a single argument) is omitted if the
26571 initializer list consists of a single expression of type cv U,
26572 where U is a specialization of C or a class derived from a
26573 specialization of C. */
26584 }
26587 else
26589 }
26590 else
26601 /* Prune explicit deduction guides in copy-initialization context. */
26603 {
26609 {
26610 /* Found a nonconverting guide, prune the candidates. */
26617 }
26618 }
26623 {
26626 }
26629 // FIXME cache artificial deduction guides
26631 {
26632 /* Skip inherited constructors. */
26642 else
26646 }
26650 /* If this is list-initialization and the class has a list constructor, first
26651 try deducing from the list as a single argument, as [over.match.list]. */
26655 {
26659 }
26661 {
26667 {
26668 /* That didn't work, now try treating the list as a sequence of
26669 arguments. */
26672 }
26673 }
26675 /* Maybe generate an implicit deduction guide. */
26677 {
26681 /* Generate a copy guide. */
26684 /* Generate a default guide. */
26688 {
26693 }
26694 }
26697 {
26699 " of %qT, as it has no non-explicit deduction guides or "
26702 }
26704 {
26708 }
26711 {
26715 }
26718 {
26728 }
26733 }
26735 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
26736 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
26737 The CONTEXT determines the context in which auto deduction is performed
26738 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
26739 OUTER_TARGS are used during template argument deduction
26740 (context == adc_unify) to properly substitute the result, and is ignored
26741 in other contexts.
26743 For partial-concept-ids, extra args may be appended to the list of deduced
26744 template arguments prior to determining constraint satisfaction. */
26746 tree
26750 {
26751 tree targs;
26758 /* Defining a subset of type-dependent expressions that we can deduce
26759 from ahead of time isn't worth the trouble. */
26762 /* Similarly, we can't deduce from another undeduced decl. */
26767 /* C++17 class template argument deduction. */
26771 /* Nothing we can do with this, even in deduction context. */
26774 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
26775 with either a new invented type template parameter U or, if the
26776 initializer is a braced-init-list (8.5.4), with
26777 std::initializer_list<U>. */
26779 {
26784 else
26785 {
26787 {
26791 "for deduction to %<std::initializer_list%>, use copy-"
26793 }
26795 }
26796 }
26807 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
26808 and initializer has array type, deduce cv-qualified array type. */
26810 complain);
26812 {
26821 {
26825 }
26826 }
26827 else
26828 {
26830 tree tparms;
26834 else
26835 {
26839 }
26843 DEDUCE_CALL,
26846 {
26848 /* Try again at instantiation time. */
26852 /* If type is error_mark_node a diagnostic must have been
26853 emitted by now. Also, having a mention to '<type error>'
26854 in the diagnostic is not really useful to the user. */
26855 {
26859 else
26862 DEDUCE_CALL,
26864 }
26866 }
26867 }
26869 /* Check any placeholder constraints against the deduced type. */
26872 {
26873 /* Use the deduced type to check the associated constraints. If we
26874 have a partial-concept-id, rebuild the argument list so that
26875 we check using the extra arguments. */
26879 {
26882 }
26883 else
26886 {
26888 {
26890 {
26908 }
26910 }
26912 }
26913 }
26919 }
26921 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
26922 result. */
26924 tree
26926 {
26928 {
26934 /* In an abbreviated function template we didn't know we were dealing
26935 with a function template when we saw the auto return type, so update
26936 it to have the correct level. */
26938 }
26940 }
26942 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26943 'decltype(auto)' or a deduced class template. */
26945 bool
26947 {
26953 else
26955 }
26957 /* for_each_template_parm callback for type_uses_auto. */
26959 int
26961 {
26963 }
26965 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26966 a use of `auto'. Returns NULL_TREE otherwise. */
26968 tree
26970 {
26974 {
26975 /* The Concepts TS allows multiple autos in one type-specifier; just
26976 return the first one we find, do_auto_deduction will collect all of
26977 them. */
26981 else
26983 }
26984 else
26986 }
26988 /* Report ill-formed occurrences of auto types in ARGUMENTS. If
26989 concepts are enabled, auto is acceptable in template arguments, but
26990 only when TEMPL identifies a template class. Return TRUE if any
26991 such errors were reported. */
26993 bool
26995 {
26996 /* If there were previous errors, nevermind. */
27000 /* If TMPL is an identifier, we're parsing and we can't tell yet
27001 whether TMPL is supposed to be a type, a function or a variable.
27002 We'll only be able to tell during template substitution, so we
27003 expect to be called again then. If concepts are enabled and we
27004 know we have a type, we're ok. */
27012 /* Quickly search for any occurrences of auto; usually there won't
27013 be any, and then we'll avoid allocating the vector. */
27021 {
27026 }
27029 }
27031 /* For a given template T, return the vector of typedefs referenced
27032 in T for which access check is needed at T instantiation time.
27033 T is either a FUNCTION_DECL or a RECORD_TYPE.
27034 Those typedefs were added to T by the function
27035 append_type_to_template_for_access_check. */
27039 {
27040 tree ti;
27051 {
27056 }
27059 }
27061 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
27062 tied to T. That list of typedefs will be access checked at
27063 T instantiation time.
27064 T is either a FUNCTION_DECL or a RECORD_TYPE.
27065 TYPE_DECL is a TYPE_DECL node representing a typedef.
27066 SCOPE is the scope through which TYPE_DECL is accessed.
27067 LOCATION is the location of the usage point of TYPE_DECL.
27069 This function is a subroutine of
27070 append_type_to_template_for_access_check. */
27072 static void
27074 tree type_decl,
27075 tree scope,
27076 location_t location)
27077 {
27078 qualified_typedef_usage_t typedef_usage;
27079 tree ti;
27086 && type_decl
27100 }
27102 /* Append TYPE_DECL to the template TEMPL.
27103 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
27104 At TEMPL instanciation time, TYPE_DECL will be checked to see
27105 if it can be accessed through SCOPE.
27106 LOCATION is the location of the usage point of TYPE_DECL.
27108 e.g. consider the following code snippet:
27110 class C
27111 {
27112 typedef int myint;
27113 };
27115 template<class U> struct S
27116 {
27117 C::myint mi; // <-- usage point of the typedef C::myint
27118 };
27120 S<char> s;
27122 At S<char> instantiation time, we need to check the access of C::myint
27123 In other words, we need to check the access of the myint typedef through
27124 the C scope. For that purpose, this function will add the myint typedef
27125 and the scope C through which its being accessed to a list of typedefs
27126 tied to the template S. That list will be walked at template instantiation
27127 time and access check performed on each typedefs it contains.
27128 Note that this particular code snippet should yield an error because
27129 myint is private to C. */
27131 void
27133 tree type_decl,
27134 tree scope,
27135 location_t location)
27136 {
27142 /* Make sure we don't append the type to the template twice. */
27149 }
27151 /* Convert the generic type parameters in PARM that match the types given in the
27152 range [START_IDX, END_IDX) from the current_template_parms into generic type
27153 packs. */
27155 tree
27157 {
27168 {
27169 /* Create a distinct parameter pack type from the current parm and add it
27170 to the replacement args to tsubst below into the generic function
27171 parameter. */
27186 }
27192 /* If there are more levels then build up the replacement with the outer
27193 template parms. */
27197 replacement);
27200 }
27202 /* Entries in the decl_constraint hash table. */
27204 {
27205 tree decl;
27206 tree ci;
27207 };
27209 /* Hashing function and equality for constraint entries. */
27211 {
27213 {
27215 }
27218 {
27220 }
27221 };
27223 /* A mapping from declarations to constraint information. Note that
27224 both templates and their underlying declarations are mapped to the
27225 same constraint information.
27227 FIXME: This is defined in pt.c because garbage collection
27228 code is not being generated for constraint.cc. */
27232 /* Returns the template constraints of declaration T. If T is not
27233 constrained, return NULL_TREE. Note that T must be non-null. */
27235 tree
27237 {
27248 else
27250 }
27252 /* Associate the given constraint information CI with the declaration
27253 T. If T is a template, then the constraints are associated with
27254 its underlying declaration. Don't build associations if CI is
27255 NULL_TREE. */
27257 void
27259 {
27271 }
27273 /* Remove the associated constraints of the declaration T. */
27275 void
27277 {
27286 }
27288 /* Memoized satisfaction results for declarations. This
27289 maps the pair (constraint_info, arguments) to the result computed
27290 by constraints_satisfied_p. */
27293 {
27294 tree ci;
27295 tree args;
27296 tree result;
27297 };
27299 /* Hashing function and equality for constraint entries. */
27302 {
27304 {
27307 }
27310 {
27312 }
27313 };
27315 /* Memoized satisfaction results for concept checks. */
27318 {
27319 tree tmpl;
27320 tree args;
27321 tree result;
27322 };
27324 /* Hashing function and equality for constraint entries. */
27327 {
27329 {
27331 }
27334 {
27339 }
27340 };
27345 /* Search for a memoized satisfaction result. Returns one of the
27346 truth value nodes if previously memoized, or NULL_TREE otherwise. */
27348 tree
27350 {
27355 else
27357 }
27359 /* Memoize the result of a satisfication test. Returns the saved result. */
27361 tree
27363 {
27370 }
27372 /* Search for a memoized satisfaction result for a concept. */
27374 tree
27376 {
27381 else
27383 }
27385 /* Memoize the result of a concept check. Returns the saved result. */
27387 tree
27389 {
27396 }
27400 /* Returns a prior concept specialization. This returns the substituted
27401 and normalized constraints defined by the concept. */
27403 tree
27405 {
27410 else
27412 }
27414 /* Save a concept expansion for later. */
27416 tree
27418 {
27425 }
27427 static hashval_t
27429 {
27438 }
27440 /* Compare the constraints of two subsumption entries. The LEFT1 and
27441 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
27442 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
27444 static bool
27446 {
27454 }
27456 /* Key/value pair for learning and memoizing subsumption results. This
27457 associates a pair of check constraints (including arguments) with
27458 a boolean value indicating the result. */
27461 {
27462 tree t1;
27463 tree t2;
27465 };
27467 /* Hashing function and equality for constraint entries. */
27470 {
27472 {
27474 }
27477 {
27482 }
27483 };
27487 /* Search for a previously cached subsumption result. */
27491 {
27496 else
27498 }
27500 /* Save a subsumption result. */
27502 bool
27504 {
27511 }
27513 /* Set up the hash table for constraint association. */
27515 void
27517 {
27526 }
27528 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
27529 0..N-1. */
27531 void
27533 {
27536 integer_type_node,
27537 NULL_TREE),
27543 }
27545 /* Set up the hash tables for template instantiations. */
27547 void
27549 {
27555 }
27557 /* Print stats about the template hash tables for -fstats. */
27559 void
27561 {
27570 }
27572 #if CHECKING_P
27576 /* Verify that build_non_dependent_expr () works, for various expressions,
27577 and that location wrappers don't affect the results. */
27579 static void
27581 {
27584 /* Verify constants, without and with location wrappers. */
27601 }
27603 /* Verify that type_dependent_expression_p () works correctly, even
27604 in the presence of location wrapper nodes. */
27606 static void
27608 {
27613 /* If no templates are involved, nothing is type-dependent. */
27619 /* Within a template, an unresolved name is always type-dependent. */
27622 /* Ensure it copes with NULL_TREE and errors. */
27626 /* A USING_DECL in a template should be type-dependent, even if wrapped
27627 with a location wrapper (PR c++/83799). */
27636 }
27638 /* Run all of the selftests within this file. */
27640 void
27642 {
27645 }