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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2017 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
45 /* The type of functions taking a tree, and some additional data, and
46 returning an int. */
49 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
50 instantiations have been deferred, either because their definitions
51 were not yet available, or because we were putting off doing the work. */
55 };
70 /* Live only within one (recursive) call to tsubst_expr. We use
71 this to pass the statement expression node from the STMT_EXPR
72 to the EXPR_STMT that is its result. */
75 // -------------------------------------------------------------------------- //
76 // Local Specialization Stack
77 //
78 // Implementation of the RAII helper for creating new local
79 // specializations.
82 {
84 }
87 {
90 }
92 /* True if we've recursed into fn_type_unification too many times. */
96 {
97 tree tmpl;
98 tree args;
99 tree spec;
100 };
103 {
106 };
112 /* Contains canonical template parameter types. The vector is indexed by
113 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
114 TREE_LIST, whose TREE_VALUEs contain the canonical template
115 parameters of various types and levels. */
118 #define UNIFY_ALLOW_NONE 0
119 #define UNIFY_ALLOW_MORE_CV_QUAL 1
120 #define UNIFY_ALLOW_LESS_CV_QUAL 2
121 #define UNIFY_ALLOW_DERIVED 4
122 #define UNIFY_ALLOW_INTEGER 8
123 #define UNIFY_ALLOW_OUTER_LEVEL 16
124 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
125 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
128 tbr_incomplete_type,
129 tbr_ambiguous_baseclass,
130 tbr_success
131 };
154 tree);
211 location_t);
221 /* Make the current scope suitable for access checking when we are
222 processing T. T can be FUNCTION_DECL for instantiated function
223 template, VAR_DECL for static member variable, or TYPE_DECL for
224 alias template (needed by instantiate_decl). */
226 static void
228 {
236 else
240 {
241 saved_access_scope = tree_cons
244 }
245 }
247 /* Restore the scope set up by push_access_scope. T is the node we
248 are processing. */
250 static void
252 {
254 {
257 }
261 else
263 }
265 /* Do any processing required when DECL (a member template
266 declaration) is finished. Returns the TEMPLATE_DECL corresponding
267 to DECL, unless it is a specialization, in which case the DECL
268 itself is returned. */
270 tree
272 {
279 {
280 tree type;
288 {
292 }
294 }
298 {
300 {
303 }
304 else
306 }
307 else
311 }
313 /* Create a template info node. */
315 tree
317 {
322 }
324 /* Return the template info node corresponding to T, whatever T is. */
326 tree
328 {
350 }
352 /* Returns the template nesting level of the indicated class TYPE.
354 For example, in:
355 template <class T>
356 struct A
357 {
358 template <class U>
359 struct B {};
360 };
362 A<T>::B<U> has depth two, while A<T> has depth one.
363 Both A<T>::B<int> and A<int>::B<U> have depth one, if
364 they are instantiations, not specializations.
366 This function is guaranteed to return 0 if passed NULL_TREE so
367 that, for example, `template_class_depth (current_class_type)' is
368 always safe. */
370 int
372 {
376 {
387 else
389 }
392 }
394 /* Subroutine of maybe_begin_member_template_processing.
395 Returns true if processing DECL needs us to push template parms. */
397 static bool
399 {
405 }
407 /* Subroutine of maybe_begin_member_template_processing.
408 Push the template parms in PARMS, starting from LEVELS steps into the
409 chain, and ending at the beginning, since template parms are listed
410 innermost first. */
412 static void
414 {
422 current_template_parms
428 NULL);
430 {
439 {
446 /* Push the CONST_DECL. */
452 }
453 }
454 }
456 /* Restore the template parameter context for a member template, a
457 friend template defined in a class definition, or a non-template
458 member of template class. */
460 void
462 {
463 tree parms;
468 {
471 /* Disregard full specializations (c++/60999). */
474 }
477 {
482 {
485 }
488 }
490 /* Remember how many levels of template parameters we pushed so that
491 we can pop them later. */
493 }
495 /* Undo the effects of maybe_begin_member_template_processing. */
497 void
499 {
508 {
512 }
513 }
515 /* Return a new template argument vector which contains all of ARGS,
516 but has as its innermost set of arguments the EXTRA_ARGS. */
518 static tree
520 {
521 tree new_args;
539 }
541 /* Like add_to_template_args, but only the outermost ARGS are added to
542 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
543 (EXTRA_ARGS) levels are added. This function is used to combine
544 the template arguments from a partial instantiation with the
545 template arguments used to attain the full instantiation from the
546 partial instantiation. */
548 static tree
550 {
551 tree new_args;
553 /* If there are more levels of EXTRA_ARGS than there are ARGS,
554 something very fishy is going on. */
557 /* If *all* the new arguments will be the EXTRA_ARGS, just return
558 them. */
562 /* For the moment, we make ARGS look like it contains fewer levels. */
567 /* Now, we restore ARGS to its full dimensions. */
571 }
573 /* Return the N levels of innermost template arguments from the ARGS. */
575 tree
577 {
578 tree new_args;
584 /* If N is 1, just return the innermost set of template arguments. */
588 /* If we're not removing anything, just return the arguments we were
589 given. */
595 /* Make a new set of arguments, not containing the outer arguments. */
602 }
604 /* The inverse of get_innermost_template_args: Return all but the innermost
605 EXTRA_LEVELS levels of template arguments from the ARGS. */
607 static tree
609 {
610 tree new_args;
616 /* If N is 1, just return the outermost set of template arguments. */
620 /* If we're not removing anything, just return the arguments we were
621 given. */
626 /* Make a new set of arguments, not containing the inner arguments. */
633 }
635 /* We've got a template header coming up; push to a new level for storing
636 the parms. */
638 void
640 {
641 /* We use a non-tag-transparent scope here, which causes pushtag to
642 put tags in this scope, rather than in the enclosing class or
643 namespace scope. This is the right thing, since we want
644 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
645 global template class, push_template_decl handles putting the
646 TEMPLATE_DECL into top-level scope. For a nested template class,
647 e.g.:
649 template <class T> struct S1 {
650 template <class T> struct S2 {};
651 };
653 pushtag contains special code to insert the TEMPLATE_DECL for S2
654 at the right scope. */
660 /* Add a dummy parameter level while we process the parameter list. */
661 current_template_parms
664 current_template_parms);
665 }
667 /* This routine is called when a specialization is declared. If it is
668 invalid to declare a specialization here, an error is reported and
669 false is returned, otherwise this routine will return true. */
671 static bool
673 {
676 /* [temp.expl.spec]
678 An explicit specialization shall be declared in the namespace of
679 which the template is a member, or, for member templates, in the
680 namespace of which the enclosing class or enclosing class
681 template is a member. An explicit specialization of a member
682 function, member class or static data member of a class template
683 shall be declared in the namespace of which the class template
684 is a member. */
686 {
689 }
691 /* [temp.expl.spec]
693 In an explicit specialization declaration for a member of a class
694 template or a member template that appears in namespace scope,
695 the member template and some of its enclosing class templates may
696 remain unspecialized, except that the declaration shall not
697 explicitly specialize a class member template if its enclosing
698 class templates are not explicitly specialized as well. */
700 {
703 }
706 }
708 /* We've just seen template <>. */
710 bool
712 {
716 }
718 /* Called at then end of processing a declaration preceded by
719 template<>. */
721 void
723 {
726 }
728 /* Any template <>'s that we have seen thus far are not referring to a
729 function specialization. */
731 void
733 {
736 }
738 /* We've just seen a template header. If SPECIALIZATION is nonzero,
739 it was of the form template <>. */
741 static void
743 {
745 template_header_count++;
746 }
748 /* We're beginning an explicit instantiation. */
750 void
752 {
755 }
758 void
760 {
763 }
765 /* An explicit specialization or partial specialization of TMPL is being
766 declared. Check that the namespace in which the specialization is
767 occurring is permissible. Returns false iff it is invalid to
768 specialize TMPL in the current namespace. */
770 static bool
772 {
775 /* [tmpl.expl.spec]
777 An explicit specialization shall be declared in a namespace enclosing the
778 specialized template. An explicit specialization whose declarator-id is
779 not qualified shall be declared in the nearest enclosing namespace of the
780 template, or, if the namespace is inline (7.3.1), any namespace from its
781 enclosing namespace set. */
784 {
787 }
790 /* Same or enclosing namespace. */
792 else
793 {
799 }
800 }
802 /* SPEC is an explicit instantiation. Check that it is valid to
803 perform this explicit instantiation in the current namespace. */
805 static void
807 {
808 tree ns;
810 /* DR 275: An explicit instantiation shall appear in an enclosing
811 namespace of its template. */
817 }
819 // Returns the type of a template specialization only if that
820 // specialization needs to be defined. Otherwise (e.g., if the type has
821 // already been defined), the function returns NULL_TREE.
822 static tree
824 {
825 // An implicit instantiation of an incomplete type implies
826 // the definition of a new class template.
827 //
828 // template<typename T>
829 // struct S;
830 //
831 // template<typename T>
832 // struct S<T*>;
833 //
834 // Here, S<T*> is an implicit instantiation of S whose type
835 // is incomplete.
839 // It can also be the case that TYPE is a completed specialization.
840 // Continuing the previous example, suppose we also declare:
841 //
842 // template<typename T>
843 // requires Integral<T>
844 // struct S<T*>;
845 //
846 // Here, S<T*> refers to the specialization S<T*> defined
847 // above. However, we need to differentiate definitions because
848 // we intend to define a new partial specialization. In this case,
849 // we rely on the fact that the constraints are different for
850 // this declaration than that above.
851 //
852 // Note that we also get here for injected class names and
853 // late-parsed template definitions. We must ensure that we
854 // do not create new type declarations for those cases.
856 {
860 // If there are no template parameters, this cannot be a new
861 // partial template specializtion?
865 // The injected-class-name is not a new partial specialization.
869 // If the constraints are not the same as those of the primary
870 // then, we can probably create a new specialization.
874 {
878 }
880 // Also, if there's a pre-existing specialization with matching
881 // constraints, then this also isn't new.
884 {
892 }
894 // Create a new type node (and corresponding type decl)
895 // for the newly declared specialization.
900 /* We only need a separate type node for storing the definition of this
901 partial specialization; uses of S<T*> are unconstrained, so all are
902 equivalent. So keep TYPE_CANONICAL the same. */
905 // Build the corresponding type decl.
911 }
914 }
916 /* The TYPE is being declared. If it is a template type, that means it
917 is a partial specialization. Do appropriate error-checking. */
919 tree
921 {
922 tree context;
927 /* A lambda that appears in specialization context is not itself a
928 specialization. */
933 {
937 }
942 {
948 else
951 }
953 {
954 /* This is for ordinary explicit specialization and partial
955 specialization of a template class such as:
957 template <> class C<int>;
959 or:
961 template <class T> class C<T*>;
963 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
966 {
973 {
978 }
979 }
985 /* Trying to define a specialization either without a template<> header
986 or in an inappropriate place. We've already given an error, so just
987 bail now so we don't actually define the specialization. */
989 }
995 {
996 /* This is for an explicit specialization of member class
997 template according to [temp.expl.spec/18]:
999 template <> template <class U> class C<int>::D;
1001 The context `C<int>' must be an implicit instantiation.
1002 Otherwise this is just a member class template declared
1003 earlier like:
1005 template <> class C<int> { template <class U> class D; };
1006 template <> template <class U> class C<int>::D;
1008 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1009 while in the second case, `C<int>::D' is a primary template
1010 and `C<T>::D' may not exist. */
1014 {
1015 tree t;
1020 {
1025 }
1027 /* Check for invalid specialization after instantiation:
1029 template <> template <> class C<int>::D<int>;
1030 template <> template <class U> class C<int>::D; */
1034 {
1038 {
1039 /* We already have a full specialization of this partial
1040 instantiation, or a full specialization has been
1041 looked up but not instantiated. Reassign it to the
1042 new member specialization template. */
1043 spec_entry elt;
1055 spec_entry **slot
1060 }
1061 else
1062 /* But if we've had an implicit instantiation, that's a
1063 problem ([temp.expl.spec]/6). */
1066 }
1068 /* Mark TYPE as a specialization. And as a result, we only
1069 have one level of template argument for the innermost
1070 class template. */
1075 }
1076 }
1078 {
1079 /* Someday C++0x may allow for enum template specialization. */
1084 else
1085 {
1088 }
1089 }
1092 }
1094 /* Returns nonzero if we can optimize the retrieval of specializations
1095 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1096 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1100 {
1103 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1104 parameter. */
1106 /* The optimized lookup depends on the fact that the
1107 template arguments for the member function template apply
1108 purely to the containing class, which is not true if the
1109 containing class is an explicit or partial
1110 specialization. */
1114 /* It is possible to have a template that is not a member
1115 template and is not a member of a template class:
1117 template <typename T>
1118 struct S { friend A::f(); };
1120 Here, the friend function is a template, but the context does
1121 not have template information. The optimized lookup relies
1122 on having ARGS be the template arguments for both the class
1123 and the function template. */
1125 }
1127 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1128 gone through coerce_template_parms by now. */
1130 static void
1132 {
1135 {
1138 {
1145 /* Allow typedefs on the type of a non-type argument, since a
1147 else
1149 }
1150 }
1152 }
1154 /* Retrieve the specialization (in the sense of [temp.spec] - a
1155 specialization is either an instantiation or an explicit
1156 specialization) of TMPL for the given template ARGS. If there is
1157 no such specialization, return NULL_TREE. The ARGS are a vector of
1158 arguments, or a vector of vectors of arguments, in the case of
1159 templates with more than one level of parameters.
1161 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1162 then we search for a partial specialization matching ARGS. This
1163 parameter is ignored if TMPL is not a class template.
1165 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1166 result is a NONTYPE_ARGUMENT_PACK. */
1168 static tree
1170 {
1180 /* There should be as many levels of arguments as there are
1181 levels of parameters. */
1191 {
1192 /* The template arguments actually apply to the containing
1193 class. Find the class specialization with those
1194 arguments. */
1196 tree class_specialization
1201 /* Find the instance of TMPL. */
1204 {
1207 /* using-declarations can add base methods to the method vec,
1208 and we don't want those here. */
1211 }
1213 }
1214 else
1215 {
1217 spec_entry elt;
1226 else
1234 }
1237 }
1239 /* Like retrieve_specialization, but for local declarations. */
1241 tree
1243 {
1249 }
1251 /* Returns nonzero iff DECL is a specialization of TMPL. */
1253 int
1255 {
1256 tree t;
1259 {
1265 }
1266 else
1267 {
1276 }
1279 }
1281 /* Returns nonzero iff DECL is a specialization of friend declaration
1282 FRIEND_DECL according to [temp.friend]. */
1284 bool
1286 {
1293 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1294 of a template class, we want to check if DECL is a specialization
1295 if this. */
1299 {
1300 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1303 }
1308 /* There is nothing to do if this is not a template friend. */
1315 /* [temp.friend/6]
1316 A member of a class template may be declared to be a friend of a
1317 non-template class. In this case, the corresponding member of
1318 every specialization of the class template is a friend of the
1319 class granting friendship.
1321 For example, given a template friend declaration
1323 template <class T> friend void A<T>::f();
1325 the member function below is considered a friend
1327 template <> struct A<int> {
1328 void f();
1329 };
1331 For this type of template friend, TEMPLATE_DEPTH below will be
1332 nonzero. To determine if DECL is a friend of FRIEND, we first
1333 check if the enclosing class is a specialization of another. */
1340 {
1341 /* Next, we check the members themselves. In order to handle
1342 a few tricky cases, such as when FRIEND_DECL's are
1344 template <class T> friend void A<T>::g(T t);
1345 template <class T> template <T t> friend void A<T>::h();
1347 and DECL's are
1349 void A<int>::g(int);
1350 template <int> void A<int>::h();
1352 we need to figure out ARGS, the template arguments from
1353 the context of DECL. This is required for template substitution
1354 of `T' in the function parameter of `g' and template parameter
1355 of `h' in the above examples. Here ARGS corresponds to `int'. */
1362 {
1364 {
1367 else
1369 current_depth++;
1370 }
1372 }
1375 {
1377 tree friend_type;
1378 tree decl_type;
1379 tree friend_args_type;
1380 tree decl_args_type;
1382 /* Make sure that both DECL and FRIEND_DECL are templates or
1383 non-templates. */
1389 {
1390 /* If both are templates, check template parameter list. */
1391 tree friend_parms
1396 friend_parms))
1400 }
1401 else
1409 /* Check if return types match. */
1413 /* Check if function parameter types match, ignoring the
1414 `this' parameter. */
1423 }
1424 else
1425 {
1426 /* DECL is a TYPE_DECL */
1430 /* Make sure that both DECL and FRIEND_DECL are templates or
1431 non-templates. */
1432 is_template
1439 {
1440 tree friend_parms;
1441 /* If both are templates, check the name of the two
1442 TEMPLATE_DECL's first because is_friend didn't. */
1447 /* Now check template parameter list. */
1448 friend_parms
1451 return comp_template_parms
1453 friend_parms);
1454 }
1455 else
1458 }
1459 }
1461 }
1463 /* Register the specialization SPEC as a specialization of TMPL with
1464 the indicated ARGS. IS_FRIEND indicates whether the specialization
1465 is actually just a friend declaration. Returns SPEC, or an
1466 equivalent prior declaration, if available.
1468 We also store instantiations of field packs in the hash table, even
1469 though they are not themselves templates, to make lookup easier. */
1471 static tree
1473 hashval_t hash)
1474 {
1475 tree fn;
1477 spec_entry elt;
1485 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1486 register it; we want the corresponding TEMPLATE_DECL instead.
1487 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1488 the more obvious `uses_template_parms (spec)' to avoid problems
1489 with default function arguments. In particular, given
1490 something like this:
1492 template <class T> void f(T t1, T t = T())
1494 the default argument expression is not substituted for in an
1495 instantiation unless and until it is actually needed. */
1499 /* We don't put these specializations in the hash table, but we might
1500 want to give an error about a mismatch. */
1502 else
1503 {
1511 slot =
1515 else
1517 }
1519 /* We can sometimes try to re-register a specialization that we've
1520 already got. In particular, regenerate_decl_from_template calls
1521 duplicate_decls which will update the specialization list. But,
1522 we'll still get called again here anyhow. It's more convenient
1523 to simply allow this than to try to prevent it. */
1527 {
1529 {
1532 {
1534 fn);
1536 }
1537 else
1538 {
1539 tree clone;
1540 /* This situation should occur only if the first
1541 specialization is an implicit instantiation, the
1542 second is an explicit specialization, and the
1543 implicit instantiation has not yet been used. That
1544 situation can occur if we have implicitly
1545 instantiated a member function and then specialized
1546 it later.
1548 We can also wind up here if a friend declaration that
1549 looked like an instantiation turns out to be a
1550 specialization:
1552 template <class T> void foo(T);
1553 class S { friend void foo<>(int) };
1554 template <> void foo(int);
1556 We transform the existing DECL in place so that any
1557 pointers to it become pointers to the updated
1558 declaration.
1560 If there was a definition for the template, but not
1561 for the specialization, we want this to look as if
1562 there were no definition, and vice versa. */
1565 /* The call to duplicate_decls will have applied
1566 [temp.expl.spec]:
1568 An explicit specialization of a function template
1569 is inline only if it is explicitly declared to be,
1570 and independently of whether its function template
1571 is.
1573 to the primary function; now copy the inline bits to
1574 the various clones. */
1576 {
1583 }
1587 }
1588 }
1590 {
1593 /* We've already complained in duplicate_decls. */
1597 /* Dup decl failed, but this is a new definition. Set the
1598 line number so any errors match this new
1599 definition. */
1603 }
1604 }
1608 /* A specialization must be declared in the same namespace as the
1609 template it is specializing. */
1615 {
1624 /* If TMPL is a forward declaration of a template function, keep a list
1625 of all specializations in case we need to reassign them to a friend
1626 template later in tsubst_friend_function.
1628 Also keep a list of all variable template instantiations so that
1629 process_partial_specialization can check whether a later partial
1630 specialization would have used it. */
1633 }
1636 }
1638 /* Returns true iff two spec_entry nodes are equivalent. */
1642 bool
1644 {
1651 /* tmpl could be a FIELD_DECL for a capture pack. */
1655 {
1656 /* Partial specializations of a variable template can be distinguished by
1657 constraints. */
1661 }
1665 }
1667 /* Returns a hash for a template TMPL and template arguments ARGS. */
1669 static hashval_t
1671 {
1674 }
1676 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1677 ignoring SPEC. */
1679 hashval_t
1681 {
1683 }
1685 /* Recursively calculate a hash value for a template argument ARG, for use
1686 in the hash tables of template specializations. */
1688 hashval_t
1690 {
1710 {
1718 {
1723 }
1745 {
1749 {
1752 }
1754 }
1758 {
1761 }
1772 val = iterative_hash_template_arg
1784 val);
1786 val);
1795 /* A lambda can't appear in a template arg, but don't crash on
1796 erroneous input. */
1808 /* Now hash operands as usual. */
1813 }
1816 {
1819 {
1820 // We want an alias specialization that survived strip_typedefs
1821 // to hash differently from its TYPE_CANONICAL, to avoid hash
1822 // collisions that compare as different in template_args_equal.
1823 // These could be dependent specializations that strip_typedefs
1824 // left alone, or untouched specializations because
1825 // coerce_template_parms returns the unconverted template
1826 // arguments if it sees incomplete argument packs.
1829 }
1832 val);
1835 /* Otherwise just compare the types during lookup. */
1844 {
1849 }
1850 }
1853 }
1855 /* Unregister the specialization SPEC as a specialization of TMPL.
1856 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1857 if the SPEC was listed as a specialization of TMPL.
1859 Note that SPEC has been ggc_freed, so we can't look inside it. */
1861 bool
1863 {
1865 spec_entry elt;
1873 {
1878 }
1881 }
1883 /* Like register_specialization, but for local declarations. We are
1884 registering SPEC, an instantiation of TMPL. */
1886 void
1888 {
1890 }
1892 /* TYPE is a class type. Returns true if TYPE is an explicitly
1893 specialized class. */
1895 bool
1897 {
1901 }
1903 /* Print the list of functions at FNS, going through all the overloads
1904 for each element of the list. Alternatively, FNS can not be a
1905 TREE_LIST, in which case it will be printed together with all the
1906 overloads.
1908 MORE and *STR should respectively be FALSE and NULL when the function
1909 is called from the outside. They are used internally on recursive
1910 calls. print_candidates manages the two parameters and leaves NULL
1911 in *STR when it ends. */
1913 static void
1915 {
1919 else
1921 {
1927 {
1930 else
1933 }
1935 }
1936 }
1938 /* Print the list of candidate FNS in an error message. FNS can also
1939 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1941 void
1943 {
1947 }
1949 /* Get a (possibly) constrained template declaration for the
1950 purpose of ordering candidates. */
1951 static tree
1953 {
1959 }
1961 /* Among candidates having the same signature, return the
1962 most constrained or NULL_TREE if there is no best candidate.
1963 If the signatures of candidates vary (e.g., template
1964 specialization vs. member function), then there can be no
1965 most constrained.
1967 Note that we don't compare constraints on the functions
1968 themselves, but rather those of their templates. */
1969 static tree
1971 {
1972 // Try to find the best candidate in a first pass.
1975 {
1982 }
1984 // Verify that the champ is better than previous candidates.
1989 }
1992 }
1995 /* Returns the template (one of the functions given by TEMPLATE_ID)
1996 which can be specialized to match the indicated DECL with the
1997 explicit template args given in TEMPLATE_ID. The DECL may be
1998 NULL_TREE if none is available. In that case, the functions in
1999 TEMPLATE_ID are non-members.
2001 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2002 specialization of a member template.
2004 The TEMPLATE_COUNT is the number of references to qualifying
2005 template classes that appeared in the name of the function. See
2006 check_explicit_specialization for a more accurate description.
2008 TSK indicates what kind of template declaration (if any) is being
2009 declared. TSK_TEMPLATE indicates that the declaration given by
2010 DECL, though a FUNCTION_DECL, has template parameters, and is
2011 therefore a template function.
2013 The template args (those explicitly specified and those deduced)
2014 are output in a newly created vector *TARGS_OUT.
2016 If it is impossible to determine the result, an error message is
2017 issued. The error_mark_node is returned to indicate failure. */
2019 static tree
2021 tree decl,
2025 tmpl_spec_kind tsk)
2026 {
2027 tree fns;
2028 tree targs;
2029 tree explicit_targs;
2032 /* A TREE_LIST of templates of which DECL may be a specialization.
2033 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2034 corresponding TREE_PURPOSE is the set of template arguments that,
2035 when used to instantiate the template, would produce a function
2036 with the signature of DECL. */
2046 /* We shouldn't be specializing a member template of an
2047 unspecialized class template; we already gave an error in
2048 check_specialization_scope, now avoid crashing. */
2051 {
2054 }
2062 /* Check for baselinks. */
2067 {
2070 }
2072 {
2075 }
2077 /* Count the number of template headers specified for this
2078 specialization. */
2088 {
2091 tf_warning_or_error,
2095 }
2097 {
2101 {
2102 tree decl_arg_types;
2103 tree fn_arg_types;
2104 tree insttype;
2106 /* In case of explicit specialization, we need to check if
2107 the number of template headers appearing in the specialization
2108 is correct. This is usually done in check_explicit_specialization,
2109 but the check done there cannot be exhaustive when specializing
2110 member functions. Consider the following code:
2112 template <> void A<int>::f(int);
2113 template <> template <> void A<int>::f(int);
2115 Assuming that A<int> is not itself an explicit specialization
2116 already, the first line specializes "f" which is a non-template
2117 member function, whilst the second line specializes "f" which
2118 is a template member function. So both lines are syntactically
2119 correct, and check_explicit_specialization does not reject
2120 them.
2122 Here, we can do better, as we are matching the specialization
2123 against the declarations. We count the number of template
2124 headers, and we check if they match TEMPLATE_COUNT + 1
2125 (TEMPLATE_COUNT is the number of qualifying template classes,
2126 plus there must be another header for the member template
2127 itself).
2129 Notice that if header_count is zero, this is not a
2130 specialization but rather a template instantiation, so there
2131 is no check we can perform here. */
2135 /* Check that the number of template arguments at the
2136 innermost level for DECL is the same as for FN. */
2144 /* DECL might be a specialization of FN. */
2148 /* For a non-static member function, we need to make sure
2149 that the const qualification is the same. Since
2150 get_bindings does not try to merge the "this" parameter,
2151 we must do the comparison explicitly. */
2157 /* Skip the "this" parameter and, for constructors of
2158 classes with virtual bases, the VTT parameter. A
2159 full specialization of a constructor will have a VTT
2160 parameter, but a template never will. */
2161 decl_arg_types
2163 fn_arg_types
2166 /* Function templates cannot be specializations; there are
2167 no partial specializations of functions. Therefore, if
2168 the type of DECL does not match FN, there is no
2169 match.
2171 Note that it should never be the case that we have both
2172 candidates added here, and for regular member functions
2173 below. */
2175 {
2179 }
2181 /* See whether this function might be a specialization of this
2182 template. Suppress access control because we might be trying
2183 to make this specialization a friend, and we have already done
2184 access control for the declaration of the specialization. */
2190 /* We cannot deduce template arguments that when used to
2191 specialize TMPL will produce DECL. */
2194 /* Remove, from the set of candidates, all those functions
2195 whose constraints are not satisfied. */
2199 // Then, try to form the new function type.
2203 fn_arg_types
2208 /* Save this template, and the arguments deduced. */
2210 }
2212 /* FN is an ordinary member function, and we need a
2213 specialization of a member template. */
2214 ;
2216 /* We can get IDENTIFIER_NODEs here in certain erroneous
2217 cases. */
2218 ;
2220 /* This is just an ordinary non-member function. Nothing can
2221 be a specialization of that. */
2222 ;
2224 /* Cannot specialize functions that are created implicitly. */
2225 ;
2226 else
2227 {
2228 tree decl_arg_types;
2230 /* This is an ordinary member function. However, since
2231 we're here, we can assume its enclosing class is a
2232 template class. For example,
2234 template <typename T> struct S { void f(); };
2235 template <> void S<int>::f() {}
2237 Here, S<int>::f is a non-template, but S<int> is a
2238 template class. If FN has the same type as DECL, we
2239 might be in business. */
2242 /* Its enclosing class is an explicit specialization
2243 of a template class. This is not a candidate. */
2248 /* The return types differ. */
2251 /* Adjust the type of DECL in case FN is a static member. */
2258 decl_arg_types))
2261 // If the deduced arguments do not satisfy the constraints,
2262 // this is not a candidate.
2266 // Add the candidate.
2268 }
2269 }
2272 {
2273 /* We have:
2275 [temp.expl.spec]
2277 It is possible for a specialization with a given function
2278 signature to be instantiated from more than one function
2279 template. In such cases, explicit specification of the
2280 template arguments must be used to uniquely identify the
2281 function template specialization being specialized.
2283 Note that here, there's no suggestion that we're supposed to
2284 determine which of the candidate templates is most
2285 specialized. However, we, also have:
2287 [temp.func.order]
2289 Partial ordering of overloaded function template
2290 declarations is used in the following contexts to select
2291 the function template to which a function template
2292 specialization refers:
2294 -- when an explicit specialization refers to a function
2295 template.
2297 So, we do use the partial ordering rules, at least for now.
2298 This extension can only serve to make invalid programs valid,
2299 so it's safe. And, there is strong anecdotal evidence that
2300 the committee intended the partial ordering rules to apply;
2301 the EDG front end has that behavior, and John Spicer claims
2302 that the committee simply forgot to delete the wording in
2303 [temp.expl.spec]. */
2306 {
2309 }
2310 }
2312 // Concepts allows multiple declarations of member functions
2313 // with the same signature. Like above, we need to rely on
2314 // on the partial ordering of those candidates to determine which
2315 // is the best.
2317 {
2319 {
2322 }
2323 }
2326 {
2333 else
2336 }
2340 {
2346 }
2348 /* We have one, and exactly one, match. */
2350 {
2354 // Propagate the candidate's constraints to the declaration.
2357 /* DECL is a re-declaration or partial instantiation of a template
2358 function. */
2361 /* It was a specialization of an ordinary member function in a
2362 template class. */
2364 }
2366 /* It was a specialization of a template. */
2369 {
2374 }
2375 else
2378 }
2380 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2381 but with the default argument values filled in from those in the
2382 TMPL_TYPES. */
2384 static tree
2386 tree tmpl_types)
2387 {
2388 tree new_spec_types;
2396 /* Substitute into the rest of the list. */
2397 new_spec_types =
2401 /* Add the default argument for this parameter. */
2404 new_spec_types);
2405 }
2407 /* DECL is an explicit specialization. Replicate default arguments
2408 from the template it specializes. (That way, code like:
2410 template <class T> void f(T = 3);
2411 template <> void f(double);
2412 void g () { f (); }
2414 works, as required.) An alternative approach would be to look up
2415 the correct default arguments at the call-site, but this approach
2416 is consistent with how implicit instantiations are handled. */
2418 static void
2420 {
2421 tree tmpl;
2422 tree spec_types;
2423 tree tmpl_types;
2424 tree new_spec_types;
2425 tree old_type;
2426 tree new_type;
2427 tree t;
2432 /* See if there's anything we need to do. */
2445 {
2446 /* Remove the this pointer, but remember the object's type for
2447 CV quals. */
2453 {
2454 /* DECL may contain more parameters than TMPL due to the extra
2455 in-charge parameter in constructors and destructors. */
2458 }
2460 {
2463 }
2464 }
2466 /* Compute the merged default arguments. */
2467 new_spec_types =
2470 /* Compute the new FUNCTION_TYPE. */
2472 {
2476 new_spec_types);
2479 /* Put the in-charge parameter back. */
2482 new_spec_types);
2486 new_spec_types);
2487 }
2488 else
2490 new_spec_types);
2500 }
2502 /* Return the number of template headers we expect to see for a definition
2503 or specialization of CTYPE or one of its non-template members. */
2505 int
2507 {
2511 {
2512 /* You're supposed to have one `template <...>' for every
2513 template class, but you don't need one for a full
2514 specialization. For example:
2516 template <class T> struct S{};
2517 template <> struct S<int> { void f(); };
2518 void S<int>::f () {}
2520 is correct; there shouldn't be a `template <>' for the
2521 definition of `S<int>::f'. */
2523 /* If CTYPE does not have template information of any
2524 kind, then it is not a template, nor is it nested
2525 within a template. */
2533 }
2536 }
2538 /* Do a simple sanity check on the template headers that precede the
2539 variable declaration DECL. */
2541 void
2543 {
2548 {
2551 "variable templates only available with "
2554 // Namespace-scope variable templates should have a template header.
2556 }
2558 {
2560 "too many template headers for %qD "
2566 "members of an explicitly specialized class are defined "
2568 }
2569 }
2571 /* An explicit specialization whose declarator-id or class-head-name is not
2572 qualified shall be declared in the nearest enclosing namespace of the
2573 template, or, if the namespace is inline (7.3.1), any namespace from its
2574 enclosing namespace set.
2576 If the name declared in the explicit instantiation is an unqualified name,
2577 the explicit instantiation shall appear in the namespace where its template
2578 is declared or, if that namespace is inline (7.3.1), any namespace from its
2579 enclosing namespace set. */
2581 void
2583 {
2588 {
2594 /* This was allowed in C++98, so only pedwarn. */
2596 "outside its namespace must use a nested-name-"
2598 }
2599 }
2601 /* Check to see if the function just declared, as indicated in
2602 DECLARATOR, and in DECL, is a specialization of a function
2603 template. We may also discover that the declaration is an explicit
2604 instantiation at this point.
2606 Returns DECL, or an equivalent declaration that should be used
2607 instead if all goes well. Issues an error message if something is
2608 amiss. Returns error_mark_node if the error is not easily
2609 recoverable.
2611 FLAGS is a bitmask consisting of the following flags:
2613 2: The function has a definition.
2614 4: The function is a friend.
2616 The TEMPLATE_COUNT is the number of references to qualifying
2617 template classes that appeared in the name of the function. For
2618 example, in
2620 template <class T> struct S { void f(); };
2621 void S<int>::f();
2623 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2624 classes are not counted in the TEMPLATE_COUNT, so that in
2626 template <class T> struct S {};
2627 template <> struct S<int> { void f(); }
2628 template <> void S<int>::f();
2630 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2631 invalid; there should be no template <>.)
2633 If the function is a specialization, it is marked as such via
2634 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2635 is set up correctly, and it is added to the list of specializations
2636 for that template. */
2638 tree
2640 tree decl,
2643 {
2652 tmpl_spec_kind tsk;
2655 {
2658 else
2660 }
2661 else
2665 {
2668 {
2671 }
2673 {
2675 /* This could be something like:
2677 template <class T> void f(T);
2678 class S { friend void f<>(int); } */
2680 else
2681 {
2682 /* This case handles bogus declarations like template <>
2683 template <class T> void f<int>(); */
2686 declarator);
2688 }
2689 }
2693 /* The error has already been reported in
2694 check_specialization_scope. */
2700 /* Fall through. */
2713 decl);
2716 else
2720 /* Fall through. */
2726 /* In cases like template<> constexpr bool v = true;
2727 We'll give an error in check_template_variable. */
2733 else
2739 {
2740 /* This case handles bogus declarations like template <>
2741 template <class T> void f<int>(); */
2745 declarator);
2747 {
2748 /* Partial specialization of variable template. */
2752 }
2756 else
2760 ok:;
2761 }
2764 /* This is a specialization of a member template, without
2765 specialization the containing class. Something like:
2767 template <class T> struct S {
2768 template <class U> void f (U);
2769 };
2770 template <> template <class U> void S<int>::f(U) {}
2772 That's a specialization -- but of the entire template. */
2778 }
2781 /* This doesn't apply to variable templates. */
2784 {
2788 {
2792 }
2793 }
2796 {
2801 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2803 {
2804 tree fns;
2809 else
2810 {
2811 /* If there is no class context, the explicit instantiation
2812 must be at namespace scope. */
2815 /* Find the namespace binding, using the declaration
2816 context. */
2820 /* If lookup fails, look for a friend declaration so we can
2821 give a better diagnostic. */
2827 {
2830 }
2831 }
2834 }
2840 {
2842 /* A specialization in class scope. This is invalid,
2843 but the error will already have been flagged by
2844 check_specialization_scope. */
2846 else
2847 {
2848 /* It's not valid to write an explicit instantiation in
2849 class scope, e.g.:
2851 class C { template void f(); }
2853 This case is caught by the parser. However, on
2854 something like:
2856 template class C { void f(); };
2858 (which is invalid) we can get here. The error will be
2859 issued later. */
2860 ;
2861 }
2864 }
2867 {
2868 // We'll match variable templates in start_decl.
2872 /* Find the list of functions in ctype that have the same
2873 name as the declared function. */
2877 {
2881 {
2882 /* From [temp.expl.spec]:
2884 If such an explicit specialization for the member
2885 of a class template names an implicitly-declared
2886 special member function (clause _special_), the
2887 program is ill-formed.
2889 Similar language is found in [temp.explicit]. */
2892 }
2895 }
2899 /* For a type-conversion operator, we cannot do a
2900 name-based lookup. We might be looking for `operator
2901 int' which will be a specialization of `operator T'.
2902 Grab all the conversion operators, and then select from
2903 them. */
2905 else
2909 {
2912 }
2913 else
2915 }
2917 /* Figure out what exactly is being specialized at this point.
2918 Note that for an explicit instantiation, even one for a
2919 member function, we cannot tell a priori whether the
2920 instantiation is for a member template, or just a member
2921 function of a template class. Even if a member template is
2922 being instantiated, the member template arguments may be
2923 elided if they can be deduced from the rest of the
2924 declaration. */
2927 member_specialization,
2928 template_count,
2929 tsk);
2932 /* We couldn't figure out what this declaration was
2933 specializing. */
2935 else
2936 {
2939 {
2941 "friend declaration %qD is not visible to "
2945 }
2953 {
2954 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2955 is done by do_decl_instantiation later. */
2961 {
2962 /* If TMPL is not the most general template (for
2963 example, if TMPL is a friend template that is
2964 injected into namespace scope), then there will
2965 be too many levels of TARGS. Remove some of them
2966 here. */
2968 tree new_targs;
2975 }
2978 }
2980 /* If we thought that the DECL was a member function, but it
2981 turns out to be specializing a static member function,
2982 make DECL a static member function as well. */
2988 /* If this is a specialization of a member template of a
2989 template class, we want to return the TEMPLATE_DECL, not
2990 the specialization of it. */
2992 {
2997 {
2998 tree parm;
3002 /* We want to use the argument list specified in the
3003 definition, not in the original declaration. */
3008 }
3011 }
3013 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3019 /* Inherit default function arguments from the template
3020 DECL is specializing. */
3024 /* This specialization has the same protection as the
3025 template it specializes. */
3029 /* 7.1.1-1 [dcl.stc]
3031 A storage-class-specifier shall not be specified in an
3032 explicit specialization...
3034 The parser rejects these, so unless action is taken here,
3035 explicit function specializations will always appear with
3036 global linkage.
3038 The action recommended by the C++ CWG in response to C++
3039 defect report 605 is to make the storage class and linkage
3040 of the explicit specialization match the templated function:
3042 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3043 */
3045 {
3049 /* A concept cannot be specialized. */
3051 {
3053 gen_tmpl);
3055 }
3057 /* This specialization has the same linkage and visibility as
3058 the function template it specializes. */
3061 {
3064 }
3067 {
3070 }
3071 }
3073 /* If DECL is a friend declaration, declared using an
3074 unqualified name, the namespace associated with DECL may
3075 have been set incorrectly. For example, in:
3077 template <typename T> void f(T);
3078 namespace N {
3079 struct S { friend void f<int>(int); }
3080 }
3082 we will have set the DECL_CONTEXT for the friend
3083 declaration to N, rather than to the global namespace. */
3088 /* This is not really a declaration of a specialization.
3089 It's just the name of an instantiation. But, it's not
3090 a request for an instantiation, either. */
3093 /* A specialization is not necessarily COMDAT. */
3099 /* If this is a full specialization, register it so that we can find
3100 it again. Partial specializations will be registered in
3101 process_partial_specialization. */
3106 /* A 'structor should already have clones. */
3112 }
3113 }
3116 }
3118 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3119 parameters. These are represented in the same format used for
3120 DECL_TEMPLATE_PARMS. */
3122 int
3124 {
3125 const_tree p1;
3126 const_tree p2;
3134 {
3146 {
3150 /* If either of the template parameters are invalid, assume
3151 they match for the sake of error recovery. */
3164 }
3165 }
3168 /* One set of parameters has more parameters lists than the
3169 other. */
3173 }
3175 /* Determine whether PARM is a parameter pack. */
3177 bool
3179 {
3180 /* Determine if we have a non-type template parameter pack. */
3187 /* If this is a list of template parameters, we could get a
3188 TYPE_DECL or a TEMPLATE_DECL. */
3192 /* Otherwise it must be a type template parameter. */
3196 }
3198 /* Determine if T is a function parameter pack. */
3200 bool
3202 {
3206 }
3208 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3209 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3211 tree
3213 {
3220 }
3222 /* Return true iff the function parameter PARAM_DECL was expanded
3223 from the function parameter pack PACK. */
3225 bool
3227 {
3232 /* The parameter pack and its pack arguments have the same
3233 DECL_PARM_INDEX. */
3235 }
3237 /* Determine whether ARGS describes a variadic template args list,
3238 i.e., one that is terminated by a template argument pack. */
3240 static bool
3242 {
3244 tree last_parm;
3258 }
3260 /* Generate a new name for the parameter pack name NAME (an
3261 IDENTIFIER_NODE) that incorporates its */
3263 static tree
3265 {
3266 /* Munge the name to include the parameter index. */
3267 #define NUMBUF_LEN 128
3281 }
3283 /* Return true if T is a primary function, class or alias template
3284 instantiation. */
3286 bool
3288 {
3302 }
3304 /* Return true if PARM is a template template parameter. */
3306 bool
3308 {
3310 }
3312 /* Return true iff PARM is a DECL representing a type template
3313 parameter. */
3315 bool
3317 {
3322 }
3324 /* Return the template parameters of T if T is a
3325 primary template instantiation, NULL otherwise. */
3327 tree
3329 {
3334 parms = INNERMOST_TEMPLATE_PARMS
3338 }
3340 /* Return the template parameters of the LEVELth level from the full list
3341 of template parameters PARMS. */
3343 tree
3345 {
3346 tree p;
3357 }
3359 /* Returns the template arguments of T if T is a template instantiation,
3360 NULL otherwise. */
3362 tree
3364 {
3372 }
3374 /* Return the argument pack elements of T if T is a template argument pack,
3375 NULL otherwise. */
3377 tree
3379 {
3385 }
3387 /* True iff FN is a function representing a built-in variadic parameter
3388 pack. */
3390 bool
3392 {
3402 }
3404 /* True iff CALL is a call to a function representing a built-in variadic
3405 parameter pack. */
3407 static bool
3409 {
3413 }
3415 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3417 static tree
3419 tree in_decl)
3420 {
3426 {
3428 {
3431 }
3436 }
3437 else
3438 {
3442 /* Calculate the largest value of len that won't make the size of the vec
3443 overflow an int. The compiler will exceed resource limits long before
3444 this, but it seems a decent place to diagnose. */
3448 {
3453 }
3461 }
3462 }
3464 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3465 CALL. */
3467 static tree
3469 tree in_decl)
3470 {
3480 }
3482 /* Structure used to track the progress of find_parameter_packs_r. */
3483 struct find_parameter_pack_data
3484 {
3485 /* TREE_LIST that will contain all of the parameter packs found by
3486 the traversal. */
3489 /* Set of AST nodes that have been visited by the traversal. */
3492 /* True iff we're making a type pack expansion. */
3494 };
3496 /* Identifies all of the argument packs that occur in a template
3497 argument and appends them to the TREE_LIST inside DATA, which is a
3498 find_parameter_pack_data structure. This is a subroutine of
3499 make_pack_expansion and uses_parameter_packs. */
3500 static tree
3502 {
3508 /* Handle type aliases/typedefs. */
3510 {
3517 }
3519 /* Identify whether this is a parameter pack or not. */
3521 {
3529 /* FALLTHRU */
3531 /* If the placeholder appears in the decl-specifier-seq of a function
3532 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3533 is a pack expansion, the invented template parameter is a template
3534 parameter pack. */
3544 {
3545 /* We don't want to walk into the type of a PARM_DECL,
3546 because we don't want to see the type parameter pack. */
3549 }
3552 /* Look through a lambda capture proxy to the field pack. */
3555 {
3561 }
3563 {
3565 find_parameter_packs_r,
3568 }
3580 /* Not a parameter pack. */
3582 }
3585 {
3586 /* Add this parameter pack to the list. */
3588 }
3594 /* This switch statement will return immediately if we don't find a
3595 parameter pack. */
3597 {
3602 /* Check the template itself. */
3605 /* Check the template arguments. */
3621 /* Fall through. */
3666 {
3667 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3668 type_pack_expansion_p to false so that any placeholders
3669 within the expression don't get marked as parameter packs. */
3677 }
3681 }
3684 }
3686 /* Determines if the expression or type T uses any parameter packs. */
3687 bool
3689 {
3698 }
3700 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3701 representation a base-class initializer into a parameter pack
3702 expansion. If all goes well, the resulting node will be an
3703 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3704 respectively. */
3705 tree
3707 {
3708 tree result;
3717 {
3718 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3719 class initializer. In this case, the TREE_PURPOSE will be a
3720 _TYPE node (representing the base class expansion we're
3721 initializing) and the TREE_VALUE will be a TREE_LIST
3722 containing the initialization arguments.
3724 The resulting expansion looks somewhat different from most
3725 expansions. Rather than returning just one _EXPANSION, we
3726 return a TREE_LIST whose TREE_PURPOSE is a
3727 TYPE_PACK_EXPANSION containing the bases that will be
3728 initialized. The TREE_VALUE will be identical to the
3729 original TREE_VALUE, which is a list of arguments that will
3730 be passed to each base. We do not introduce any new pack
3731 expansion nodes into the TREE_VALUE (although it is possible
3732 that some already exist), because the TREE_PURPOSE and
3733 TREE_VALUE all need to be expanded together with the same
3734 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3735 resulting TREE_PURPOSE will mention the parameter packs in
3736 both the bases and the arguments to the bases. */
3737 tree purpose;
3738 tree value;
3741 /* Determine which parameter packs will be used by the base
3742 class expansion. */
3751 {
3755 }
3758 {
3759 /* Collect the sets of parameter packs used in each of the
3760 initialization arguments. */
3762 {
3763 /* Determine which parameter packs will be expanded in this
3764 argument. */
3767 }
3768 }
3772 /* Create the pack expansion type for the base type. */
3777 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3778 they will rarely be compared to anything. */
3782 }
3787 /* Build the PACK_EXPANSION_* node. */
3788 result = for_types
3793 {
3794 /* Propagate type and const-expression information. */
3797 /* Mark this read now, since the expansion might be length 0. */
3799 }
3800 else
3801 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3802 they will rarely be compared to anything. */
3805 /* Determine which parameter packs will be expanded. */
3812 /* Make sure we found some parameter packs. */
3814 {
3817 else
3820 }
3826 }
3828 /* Checks T for any "bare" parameter packs, which have not yet been
3829 expanded, and issues an error if any are found. This operation can
3830 only be done on full expressions or types (e.g., an expression
3831 statement, "if" condition, etc.), because we could have expressions like:
3833 foo(f(g(h(args)))...)
3835 where "args" is a parameter pack. check_for_bare_parameter_packs
3836 should not be called for the subexpressions args, h(args),
3837 g(h(args)), or f(g(h(args))), because we would produce erroneous
3838 error messages.
3840 Returns TRUE and emits an error if there were bare parameter packs,
3841 returns FALSE otherwise. */
3842 bool
3844 {
3861 {
3865 {
3876 else
3881 else
3885 }
3888 }
3891 }
3893 /* Expand any parameter packs that occur in the template arguments in
3894 ARGS. */
3895 tree
3897 {
3906 /* First, determine if we need to expand anything, and the number of
3907 slots we'll need. */
3909 {
3914 {
3918 else
3920 }
3921 else
3922 {
3924 num_result_args++;
3925 }
3926 }
3928 /* If no expansion is necessary, we're done. */
3932 /* Expand arguments. */
3935 non_default_args_count =
3938 {
3941 {
3948 }
3949 else
3950 {
3953 }
3954 }
3958 }
3960 /* Checks if DECL shadows a template parameter.
3962 [temp.local]: A template-parameter shall not be redeclared within its
3963 scope (including nested scopes).
3965 Emits an error and returns TRUE if the DECL shadows a parameter,
3966 returns FALSE otherwise. */
3968 bool
3970 {
3971 tree olddecl;
3973 /* If we're not in a template, we can't possibly shadow a template
3974 parameter. */
3978 /* Figure out what we're shadowing. */
3982 /* If there's no previous binding for this name, we're not shadowing
3983 anything, let alone a template parameter. */
3987 /* If we're not shadowing a template parameter, we're done. Note
3988 that OLDDECL might be an OVERLOAD (or perhaps even an
3989 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3990 node. */
3994 /* We check for decl != olddecl to avoid bogus errors for using a
3995 name inside a class. We check TPFI to avoid duplicate errors for
3996 inline member templates. */
4002 /* Don't complain about the injected class name, as we've already
4003 complained about the class itself. */
4010 else
4015 }
4017 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4018 ORIG_LEVEL, DECL, and TYPE. */
4020 static tree
4024 tree decl,
4025 tree type)
4026 {
4037 }
4039 /* Find the canonical type parameter for the given template type
4040 parameter. Returns the canonical type parameter, which may be TYPE
4041 if no such parameter existed. */
4043 static tree
4045 {
4046 tree list;
4060 else
4061 {
4065 }
4066 }
4068 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4069 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4070 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4071 new one is created. */
4073 static tree
4075 tsubst_flags_t complain)
4076 {
4081 {
4100 /* Template template parameters need this. */
4102 {
4109 }
4110 }
4113 }
4115 /* Process information from new template parameter PARM and append it
4116 to the LIST being built. This new parameter is a non-type
4117 parameter iff IS_NON_TYPE is true. This new parameter is a
4118 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4119 is in PARM_LOC. */
4121 tree
4124 {
4133 {
4137 {
4141 else
4143 }
4146 }
4149 {
4155 {
4156 /* [temp.param]
4158 The top-level cv-qualifiers on the template-parameter are
4159 ignored when determining its type. */
4164 && !is_parameter_pack
4165 /* If we're in a nested template parameter list, the template
4166 template parameter could be a parameter pack. */
4168 {
4169 /* This template parameter is not a parameter pack, but it
4170 should be. Complain about "bare" parameter packs. */
4173 /* Recover by calling this a parameter pack. */
4175 }
4176 }
4178 /* A template parameter is not modifiable. */
4187 processing_template_decl,
4192 }
4193 else
4194 {
4195 tree t;
4199 {
4201 /* This is for distinguishing between real templates and template
4202 template parameters */
4206 }
4207 else
4208 {
4210 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4213 }
4220 processing_template_decl,
4224 }
4228 /* Build requirements for the type/template parameter.
4229 This must be done after SET_DECL_TEMPLATE_PARM_P or
4230 process_template_parm could fail. */
4235 /* Build the parameter node linking the parameter declaration,
4236 its default argument (if any), and its constraints (if any). */
4241 }
4243 /* The end of a template parameter list has been reached. Process the
4244 tree list into a parameter vector, converting each parameter into a more
4245 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4246 as PARM_DECLs. */
4248 tree
4250 {
4255 /* Pop the dummy parameter level and add the real one. */
4258 current_template_parms
4263 {
4267 }
4272 }
4274 // Explicitly indicate the end of the template parameter list. We assume
4275 // that the current template parameters have been constructed and/or
4276 // managed explicitly, as when creating new template template parameters
4277 // from a shorthand constraint.
4278 void
4280 {
4282 }
4284 /* end_template_decl is called after a template declaration is seen. */
4286 void
4288 {
4294 /* This matches the pushlevel in begin_template_parm_list. */
4299 }
4301 /* Takes a TREE_LIST representing a template parameter and convert it
4302 into an argument suitable to be passed to the type substitution
4303 functions. Note that If the TREE_LIST contains an error_mark
4304 node, the returned argument is error_mark_node. */
4306 tree
4308 {
4321 {
4325 {
4326 /* Turn this argument into a TYPE_ARGUMENT_PACK
4327 with a single element, which expands T. */
4336 }
4337 }
4338 else
4339 {
4343 {
4344 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4345 with a single element, which expands T. */
4355 }
4356 else
4358 }
4360 }
4362 /* Given a single level of template parameters (a TREE_VEC), return it
4363 as a set of template arguments. */
4365 static tree
4367 {
4377 }
4379 /* Given a set of template parameters, return them as a set of template
4380 arguments. The template parameters are represented as a TREE_VEC, in
4381 the form documented in cp-tree.h for template arguments. */
4383 static tree
4385 {
4386 tree header;
4391 /* If there is only one level of template parameters, we do not
4392 create a TREE_VEC of TREE_VECs. Instead, we return a single
4393 TREE_VEC containing the arguments. */
4398 {
4403 else
4405 }
4408 }
4410 /* Within the declaration of a template, return the currently active
4411 template parameters as an argument TREE_VEC. */
4413 static tree
4415 {
4417 }
4419 /* Update the declared TYPE by doing any lookups which were thought to be
4420 dependent, but are not now that we know the SCOPE of the declarator. */
4422 tree
4424 {
4435 /* Don't bother building up the args in this case. */
4437 {
4438 /* tsubst in the args corresponding to the template parameters,
4439 including auto if present. Most things will be unchanged, but
4440 make_typename_type and tsubst_qualified_id will resolve
4441 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4444 tree pushed;
4446 {
4450 }
4455 }
4461 {
4464 else
4466 }
4468 }
4470 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4471 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4472 the new template is a member template. */
4474 tree
4476 {
4484 }
4486 struct template_parm_data
4487 {
4488 /* The level of the template parameters we are currently
4489 processing. */
4492 /* The index of the specialization argument we are currently
4493 processing. */
4496 /* An array whose size is the number of template parameters. The
4497 elements are nonzero if the parameter has been used in any one
4498 of the arguments processed so far. */
4501 /* An array whose size is the number of template arguments. The
4502 elements are nonzero if the argument makes use of template
4503 parameters of this level. */
4505 };
4507 /* Subroutine of push_template_decl used to see if each template
4508 parameter in a partial specialization is used in the explicit
4509 argument list. If T is of the LEVEL given in DATA (which is
4510 treated as a template_parm_data*), then DATA->PARMS is marked
4511 appropriately. */
4513 static int
4515 {
4523 {
4526 }
4528 /* In C++17 the type of a non-type argument is a deduced context. */
4533 data,
4534 NULL,
4537 /* Return zero so that for_each_template_parm will continue the
4538 traversal of the tree; we want to mark *every* template parm. */
4540 }
4542 /* Process the partial specialization DECL. */
4544 static tree
4546 {
4553 tree inner_parms;
4554 tree inst;
4564 /* A concept cannot be specialized. */
4566 {
4569 }
4574 /* We check that each of the template parameters given in the
4575 partial specialization is used in the argument list to the
4576 specialization. For example:
4578 template <class T> struct S;
4579 template <class T> struct S<T*>;
4581 The second declaration is OK because `T*' uses the template
4582 parameter T, whereas
4584 template <class T> struct S<int>;
4586 is no good. Even trickier is:
4588 template <class T>
4589 struct S1
4590 {
4591 template <class U>
4592 struct S2;
4593 template <class U>
4594 struct S2<T>;
4595 };
4597 The S2<T> declaration is actually invalid; it is a
4598 full-specialization. Of course,
4600 template <class U>
4601 struct S2<T (*)(U)>;
4603 or some such would have been OK. */
4611 {
4616 NULL,
4618 }
4621 {
4622 /* One of the template parms was not used in a deduced context in the
4623 specialization. */
4625 {
4629 }
4633 }
4638 /* [temp.class.spec]
4640 The argument list of the specialization shall not be identical to
4641 the implicit argument list of the primary template. */
4642 tree main_args
4645 && (!flag_concepts
4648 {
4652 else
4656 }
4658 /* A partial specialization that replaces multiple parameters of the
4659 primary template with a pack expansion is less specialized for those
4660 parameters. */
4662 {
4664 "primary template because it replaces multiple parameters "
4667 /* Avoid crash in process_partial_specialization. */
4669 }
4671 /* If we aren't in a dependent class, we can actually try deduction. */
4673 /* FIXME we should be able to handle a partial specialization of a
4674 partial instantiation, but currently we can't (c++/41727). */
4677 {
4681 maintmpl);
4682 }
4684 /* [temp.class.spec]
4686 A partially specialized non-type argument expression shall not
4687 involve template parameters of the partial specialization except
4688 when the argument expression is a simple identifier.
4690 The type of a template parameter corresponding to a specialized
4691 non-type argument shall not be dependent on a parameter of the
4692 specialization.
4694 Also, we verify that pack expansions only occur at the
4695 end of the argument list. */
4699 {
4706 {
4707 /* Extract the arguments from the argument pack. We'll be
4708 iterating over these in the following loop. */
4711 }
4714 {
4716 /* Get the Jth argument in the parameter pack. */
4720 {
4721 /* Pack expansions must come at the end of the
4722 argument list. */
4725 {
4729 else
4732 }
4733 }
4736 /* We only care about the pattern. */
4742 /* This next two lines are the `argument expression is not just a
4743 simple identifier' condition and also the `specialized
4744 non-type argument' bit. */
4748 {
4752 arg);
4753 else
4754 {
4755 /* Look at the corresponding template parameter,
4756 marking which template parameters its type depends
4757 upon. */
4761 {
4762 /* We haven't yet initialized TPD2. Do so now. */
4764 /* The number of parameters here is the number in the
4765 main template, which, as checked in the assertion
4766 above, is NARGS. */
4770 }
4772 /* Mark the template parameters. But this time, we're
4773 looking for the template parameters of the main
4774 template, not in the specialization. */
4781 NULL,
4785 {
4786 /* The type depended on some template parameters.
4787 If they are fully specialized in the
4788 specialization, that's OK. */
4797 "type %qT of template argument %qE depends "
4799 "type %qT of template argument %qE depends "
4801 type,
4802 arg);
4803 }
4804 }
4805 }
4806 }
4807 }
4809 /* We should only get here once. */
4813 // Build the template decl.
4822 /* Give template template parms a DECL_CONTEXT of the template
4823 for which they are a parameter. */
4825 {
4829 }
4832 /* We didn't register this in check_explicit_specialization so we could
4833 wait until the constraints were set. */
4835 else
4845 {
4851 {
4859 "declaration of %qD ambiguates earlier template "
4863 "partial specialization of %qD after instantiation "
4865 }
4866 }
4869 }
4871 /* PARM is a template parameter of some form; return the corresponding
4872 TEMPLATE_PARM_INDEX. */
4874 static tree
4876 {
4889 }
4891 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4892 parameter packs used by the template parameter PARM. */
4894 static void
4896 {
4897 /* A type parm can't refer to another parm. */
4901 {
4905 }
4912 }
4914 /* PARM is a template parameter pack. Return any parameter packs used in
4915 its type or the type of any of its template parameters. If there are
4916 any such packs, it will be instantiated into a fixed template parameter
4917 list by partial instantiation rather than be fully deduced. */
4919 tree
4921 {
4922 /* This can only be true in a member template. */
4925 /* This can only be true for a parameter pack. */
4928 /* A type parm can't refer to another parm. */
4942 }
4944 /* Check that a template declaration's use of default arguments and
4945 parameter packs is not invalid. Here, PARMS are the template
4946 parameters. IS_PRIMARY is true if DECL is the thing declared by
4947 a primary template. IS_PARTIAL is true if DECL is a partial
4948 specialization.
4950 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4951 declaration (but not a definition); 1 indicates a declaration, 2
4952 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4953 emitted for extraneous default arguments.
4955 Returns TRUE if there were no errors found, FALSE otherwise. */
4957 bool
4960 {
4963 tree parm_level;
4966 /* [temp.param]
4968 A default template-argument shall not be specified in a
4969 function template declaration or a function template definition, nor
4970 in the template-parameter-list of the definition of a member of a
4971 class template. */
4975 /* You can't have a function template declaration in a local
4976 scope, nor you can you define a member of a class template in a
4977 local scope. */
4985 /* A lambda doesn't have an explicit declaration; don't complain
4986 about the parms of the enclosing class. */
4993 /* If this is either a friend defined in the scope of the class
4994 or a member function. */
5000 /* And, if it was a member function, it really was defined in
5001 the scope of the class. */
5004 /* We already checked these parameters when the template was
5005 declared, so there's no need to do it again now. This function
5006 was defined in class scope, but we're processing its body now
5007 that the class is complete. */
5010 /* Core issue 226 (C++0x only): the following only applies to class
5011 templates. */
5014 {
5015 /* [temp.param]
5017 If a template-parameter has a default template-argument, all
5018 subsequent template-parameters shall have a default
5019 template-argument supplied. */
5021 {
5028 {
5038 {
5040 /* For better subsequent error-recovery, we indicate that
5041 there should have been a default argument. */
5044 }
5046 && !is_friend_decl
5047 /* Don't complain about an enclosing partial
5048 specialization. */
5053 /* A fixed parameter pack will be partially
5054 instantiated into a fixed length list. */
5056 {
5057 /* A primary class template can only have one
5058 parameter pack, at the end of the template
5059 parameter list. */
5067 }
5068 }
5069 }
5070 }
5073 || is_partial
5074 || !is_primary
5076 /* For an ordinary class template, default template arguments are
5077 allowed at the innermost level, e.g.:
5078 template <class T = int>
5079 struct S {};
5080 but, in a partial specialization, they're not allowed even
5081 there, as we have in [temp.class.spec]:
5083 The template parameter list of a specialization shall not
5084 contain default template argument values.
5086 So, for a partial specialization, or for a function template
5087 (in C++98/C++03), we look at all of them. */
5088 ;
5089 else
5090 /* But, for a primary class template that is not a partial
5091 specialization we look at all template parameters except the
5092 innermost ones. */
5095 /* Figure out what error message to issue. */
5110 else
5111 /* Per [temp.param]/9, "A default template-argument shall not be
5112 specified in the template-parameter-lists of the definition of
5113 a member of a class template that appears outside of the member's
5114 class.", thus if we aren't handling a member of a class template
5115 there is no need to examine the parameters. */
5119 /* If we're inside a class definition, there's no need to
5120 examine the parameters to the class itself. On the one
5121 hand, they will be checked when the class is defined, and,
5122 on the other, default arguments are valid in things like:
5123 template <class T = double>
5124 struct S { template <class U> void f(U); };
5125 Here the default argument for `S' has no bearing on the
5126 declaration of `f'. */
5128 else
5129 /* Check everything. */
5135 {
5142 {
5147 {
5149 {
5156 }
5158 /* Clear out the default argument so that we are not
5159 confused later. */
5161 }
5162 }
5164 /* At this point, if we're still interested in issuing messages,
5165 they must apply to classes surrounding the object declared. */
5169 }
5172 }
5174 /* Worker for push_template_decl_real, called via
5175 for_each_template_parm. DATA is really an int, indicating the
5176 level of the parameters we are interested in. If T is a template
5177 parameter of that level, return nonzero. */
5179 static int
5181 {
5187 else
5190 }
5192 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5193 DATA is really an int, indicating the innermost outer level of parameters.
5194 If T is a template parameter of that level or further out, return
5195 nonzero. */
5197 static int
5199 {
5205 else
5208 }
5210 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5211 parameters given by current_template_args, or reuses a
5212 previously existing one, if appropriate. Returns the DECL, or an
5213 equivalent one, if it is replaced via a call to duplicate_decls.
5215 If IS_FRIEND is true, DECL is a friend declaration. */
5217 tree
5219 {
5220 tree tmpl;
5221 tree args;
5222 tree info;
5223 tree ctx;
5227 /* True if the template is a member template, in the sense of
5228 [temp.mem]. */
5234 /* See if this is a partial specialization. */
5247 /* For a friend, we want the context of the friend function, not
5248 the type of which it is a friend. */
5252 /* In the case of a virtual function, we want the class in which
5253 it is defined. */
5255 else
5256 /* Otherwise, if we're currently defining some class, the DECL
5257 is assumed to be a member of the class. */
5266 /* See if this is a primary template. */
5269 /* A friend template that specifies a class context, i.e.
5270 template <typename T> friend void A<T>::f();
5271 is not primary. */
5276 else
5280 {
5287 {
5290 }
5292 {
5294 {
5297 }
5299 {
5300 /* [temp.mem]
5302 A destructor shall not be a member template. */
5305 }
5312 {
5313 /* [basic.stc.dynamic.allocation]
5315 An allocation function can be a function
5316 template. ... Template allocation functions shall
5317 have two or more parameters. */
5320 }
5321 }
5324 {
5325 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5328 {
5334 }
5335 }
5338 /* alias-declaration */
5342 else
5343 {
5346 }
5347 }
5349 /* Check to see that the rules regarding the use of default
5350 arguments are not being violated. */
5354 /* Ensure that there are no parameter packs in the type of this
5355 declaration that have not been expanded. */
5357 {
5358 /* Check each of the arguments individually to see if there are
5359 any bare parameter packs. */
5365 {
5368 {
5369 /* This is a PARM_DECL that contains unexpanded parameter
5370 packs. We have already complained about this in the
5371 check_for_bare_parameter_packs call, so just replace
5372 these types with ERROR_MARK_NODE. */
5375 }
5379 }
5381 /* Check for bare parameter packs in the return type and the
5382 exception specifiers. */
5384 /* Errors were already issued, set return type to int
5385 as the frontend doesn't expect error_mark_node as
5386 the return type. */
5390 }
5395 {
5398 }
5411 {
5416 /* If DECL is a TYPE_DECL for a class-template, then there won't
5417 be DECL_LANG_SPECIFIC. The information equivalent to
5418 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5422 {
5423 /* Since a template declaration already existed for this
5424 class-type, we must be redeclaring it here. Make sure
5425 that the redeclaration is valid. */
5427 current_template_parms,
5429 /* We don't need to create a new TEMPLATE_DECL; just use the
5430 one we already had. */
5432 }
5433 else
5434 {
5436 member_template_p);
5441 {
5442 /* A specialization of a member template of a template
5443 class. */
5447 }
5448 }
5449 }
5450 else
5451 {
5457 {
5460 }
5468 {
5469 tree new_tmpl;
5471 /* The declaration is a specialization of a member
5472 template, declared outside the class. Therefore, the
5473 innermost template arguments will be NULL, so we
5474 replace them with the arguments determined by the
5475 earlier call to check_explicit_specialization. */
5478 new_tmpl
5480 member_template_p);
5490 args,
5493 }
5495 /* Make sure the template headers we got make sense. */
5500 {
5505 }
5506 else
5508 {
5513 {
5517 else
5521 /* Avoid crash in import_export_decl. */
5524 }
5529 /* Can happen in erroneous input. */
5531 else
5533 }
5535 /* Check that the parms are used in the appropriate qualifying scopes
5536 in the declarator. */
5540 {
5546 /* Avoid crash in import_export_decl. */
5549 }
5550 }
5555 /* Push template declarations for global functions and types. Note
5556 that we do not try to push a global template friend declared in a
5557 template class; such a thing may well depend on the template
5558 parameters of the class. */
5561 {
5566 /* Hide template friend classes that haven't been declared yet. */
5568 {
5571 }
5572 }
5575 {
5581 {
5584 /* It is a conversion operator. See if the type converted to
5585 depends on innermost template operands. */
5588 depth))
5590 }
5592 /* Give template template parms a DECL_CONTEXT of the template
5593 for which they are a parameter. */
5596 {
5600 }
5606 }
5608 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5609 back to its most general template. If TMPL is a specialization,
5610 ARGS may only have the innermost set of arguments. Add the missing
5611 argument levels if necessary. */
5619 else
5620 {
5625 }
5628 && !is_friend
5631 /* Set DECL_COMDAT on template instantiations; if we force
5632 them to be emitted by explicit instantiation or -frepo,
5633 mark_needed will tell cgraph to do the right thing. */
5637 }
5639 tree
5641 {
5643 }
5645 /* FN is an inheriting constructor that inherits from the constructor
5646 template INHERITED; turn FN into a constructor template with a matching
5647 template header. */
5649 tree
5651 {
5652 tree inner_parms
5655 tree parms
5666 }
5668 /* Called when a class template TYPE is redeclared with the indicated
5669 template PARMS, e.g.:
5671 template <class T> struct S;
5672 template <class T> struct S {}; */
5674 bool
5676 {
5677 tree tmpl;
5678 tree tmpl_parms;
5682 {
5685 }
5689 /* The type is nested in some template class. Nothing to worry
5690 about here; there are no new template parameters for the nested
5691 type. */
5695 {
5697 tmpl);
5699 }
5705 {
5715 }
5718 {
5719 tree tmpl_parm;
5720 tree parm;
5721 tree tmpl_default;
5722 tree parm_default;
5736 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5737 TEMPLATE_DECL. */
5747 {
5751 }
5754 {
5755 /* We have in [temp.param]:
5757 A template-parameter may not be given default arguments
5758 by two different declarations in the same scope. */
5763 }
5766 /* Update the previous template parameters (which are the ones
5767 that will really count) with the new default value. */
5770 /* Update the new parameters, too; they'll be used as the
5771 parameters for any members. */
5774 /* Give each template template parm in this redeclaration a
5775 DECL_CONTEXT of the template for which they are a parameter. */
5777 {
5780 }
5784 }
5786 // Cannot redeclare a class template with a different set of constraints.
5788 {
5793 }
5796 }
5798 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5799 to be used when the caller has already checked
5800 (processing_template_decl
5801 && !instantiation_dependent_expression_p (expr)
5802 && potential_constant_expression (expr))
5803 and cleared processing_template_decl. */
5805 tree
5807 {
5810 complain,
5814 }
5816 /* Simplify EXPR if it is a non-dependent expression. Returns the
5817 (possibly simplified) expression. */
5819 tree
5821 {
5825 /* If we're in a template, but EXPR isn't value dependent, simplify
5826 it. We're supposed to treat:
5828 template <typename T> void f(T[1 + 1]);
5829 template <typename T> void f(T[2]);
5831 as two declarations of the same function, for example. */
5834 {
5835 processing_template_decl_sentinel s;
5837 }
5839 }
5841 tree
5843 {
5845 }
5847 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5848 an uninstantiated expression. */
5850 tree
5852 {
5856 {
5859 else
5860 {
5861 processing_template_decl_sentinel s;
5863 }
5864 }
5866 }
5868 /* True iff T is a specialization of a variable template. */
5870 bool
5872 {
5877 }
5879 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5880 template declaration, or a TYPE_DECL for an alias declaration. */
5882 bool
5884 {
5892 }
5894 /* Return TRUE iff T is a specialization of an alias template. */
5896 bool
5898 {
5899 /* It's an alias template specialization if it's an alias and its
5900 TYPE_NAME is a specialization of a primary template. */
5906 }
5908 /* An alias template is complex from a SFINAE perspective if a template-id
5909 using that alias can be ill-formed when the expansion is not, as with
5910 the void_t template. We determine this by checking whether the
5911 expansion for the alias template uses all its template parameters. */
5913 struct uses_all_template_parms_data
5914 {
5917 };
5919 static int
5921 {
5929 }
5931 static bool
5933 {
5948 }
5950 /* Return TRUE iff T is a specialization of a complex alias template with
5951 dependent template-arguments. */
5953 bool
5955 {
5968 }
5970 /* Return the number of innermost template parameters in TMPL. */
5972 static int
5974 {
5977 }
5979 /* Return either TMPL or another template that it is equivalent to under DR
5980 1286: An alias that just changes the name of a template is equivalent to
5981 the other template. */
5983 static tree
5985 {
5988 {
5989 /* Determine if the alias is equivalent to an underlying template. */
6001 tree alias_args = INNERMOST_TEMPLATE_ARGS
6006 /* Alias is equivalent. Strip it and repeat. */
6008 }
6011 }
6013 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6014 must be a reference-to-function or a pointer-to-function type, as specified
6015 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6016 and check that the resulting function has external linkage. */
6018 static tree
6020 tsubst_flags_t complain)
6021 {
6024 linkage_kind linkage;
6039 /* [temp.arg.nontype]/1
6041 A template-argument for a non-type, non-template template-parameter
6042 shall be one of:
6043 [...]
6044 -- the address of an object or function with external [C++11: or
6045 internal] linkage. */
6048 {
6050 {
6056 else
6059 }
6061 }
6065 {
6067 {
6072 else
6076 }
6078 }
6080 accept:
6087 }
6089 /* Subroutine of convert_nontype_argument.
6090 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6091 Emit an error otherwise. */
6093 static bool
6095 tsubst_flags_t complain)
6096 {
6113 {
6118 else
6120 }
6122 }
6124 /* Returns TRUE iff the address of OP is value-dependent.
6126 14.6.2.4 [temp.dep.temp]:
6127 A non-integral non-type template-argument is dependent if its type is
6128 dependent or it has either of the following forms
6129 qualified-id
6130 & qualified-id
6131 and contains a nested-name-specifier which specifies a class-name that
6132 names a dependent type.
6134 We generalize this to just say that the address of a member of a
6135 dependent class is value-dependent; the above doesn't cover the
6136 address of a static data member named with an unqualified-id. */
6138 static bool
6140 {
6141 /* We could use get_inner_reference here, but there's no need;
6142 this is only relevant for template non-type arguments, which
6143 can only be expressed as &id-expression. */
6145 {
6149 }
6152 }
6154 /* The next set of functions are used for providing helpful explanatory
6155 diagnostics for failed overload resolution. Their messages should be
6156 indented by two spaces for consistency with the messages in
6157 call.c */
6159 static int
6161 {
6163 }
6165 /* Other failure functions should call this one, to provide a single function
6166 for setting a breakpoint on. */
6168 static int
6170 {
6172 }
6174 static int
6176 {
6181 }
6183 static int
6185 {
6191 }
6193 static int
6195 {
6199 }
6201 static int
6203 {
6206 " template parameter %qD is not a parameter pack, but "
6210 }
6212 static int
6214 {
6217 " template argument %qE does not match "
6221 }
6223 static int
6225 {
6229 }
6231 static int
6233 {
6239 }
6241 static int
6243 {
6245 {
6250 else
6252 " deduced conflicting values for non-type parameter "
6254 }
6256 }
6258 static int
6260 {
6263 " variable-sized array type %qT is not "
6265 arg);
6267 }
6269 static int
6271 {
6275 arg);
6277 }
6279 static int
6281 {
6283 {
6289 else
6294 }
6296 }
6298 static int
6300 {
6302 }
6304 static int
6307 {
6309 }
6311 static int
6314 {
6320 }
6322 static int
6325 {
6328 {
6336 }
6338 }
6340 static int
6342 {
6345 " template parameters of a template template argument are "
6348 }
6350 static int
6352 {
6358 }
6360 static int
6362 {
6367 }
6369 static int
6371 {
6375 arg);
6377 }
6379 /* Attempt to convert the non-type template parameter EXPR to the
6380 indicated TYPE. If the conversion is successful, return the
6381 converted value. If the conversion is unsuccessful, return
6382 NULL_TREE if we issued an error message, or error_mark_node if we
6383 did not. We issue error messages for out-and-out bad template
6384 parameters, but not simply because the conversion failed, since we
6385 might be just trying to do argument deduction. Both TYPE and EXPR
6386 must be non-dependent.
6388 The conversion follows the special rules described in
6389 [temp.arg.nontype], and it is much more strict than an implicit
6390 conversion.
6392 This function is called twice for each template argument (see
6393 lookup_template_class for a more accurate description of this
6394 problem). This means that we need to handle expressions which
6395 are not valid in a C++ source, but can be created from the
6396 first call (for instance, casts to perform conversions). These
6397 hacks can go away after we fix the double coercion problem. */
6399 static tree
6401 {
6402 tree expr_type;
6406 /* Detect immediately string literals as invalid non-type argument.
6407 This special-case is not needed for correctness (we would easily
6408 catch this later), but only to provide better diagnostic for this
6409 common user mistake. As suggested by DR 100, we do not mention
6410 linkage issues in the diagnostic as this is not the point. */
6411 /* FIXME we're making this OK. */
6413 {
6419 }
6421 /* Add the ADDR_EXPR now for the benefit of
6422 value_dependent_expression_p. */
6425 {
6429 }
6431 /* If we are in a template, EXPR may be non-dependent, but still
6432 have a syntactic, rather than semantic, form. For example, EXPR
6433 might be a SCOPE_REF, rather than the VAR_DECL to which the
6434 SCOPE_REF refers. Preserving the qualifying scope is necessary
6435 so that access checking can be performed when the template is
6436 instantiated -- but here we need the resolved form so that we can
6437 convert the argument. */
6450 else
6453 /* If the argument is non-dependent, perform any conversions in
6454 non-dependent context as well. */
6462 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6463 to a non-type argument of "nullptr". */
6467 /* In C++11, integral or enumeration non-type template arguments can be
6468 arbitrary constant expressions. Pointer and pointer to
6469 member arguments can be general constant expressions that evaluate
6470 to a null value, but otherwise still need to be of a specific form. */
6472 {
6474 /* A PTRMEM_CST is already constant, and a valid template
6475 argument for a parameter of pointer to member type, we just want
6476 to leave it in that form rather than lower it to a
6480 {
6481 /* C++17: A template-argument for a non-type template-parameter shall
6482 be a converted constant expression (8.20) of the type of the
6483 template-parameter. */
6489 }
6491 {
6496 }
6497 }
6499 /* HACK: Due to double coercion, we can get a
6500 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6501 which is the tree that we built on the first call (see
6502 below when coercing to reference to object or to reference to
6503 function). We just strip everything and get to the arg.
6504 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6505 for examples. */
6507 {
6513 {
6514 /* ??? Maybe we could use convert_from_reference here, but we
6515 would need to relax its constraints because the NOP_EXPR
6516 could actually change the type to something more cv-qualified,
6517 and this is not folded by convert_from_reference. */
6522 && (same_type_ignoring_top_level_qualifiers_p
6525 {
6528 }
6529 }
6530 }
6532 /* [temp.arg.nontype]/5, bullet 1
6534 For a non-type template-parameter of integral or enumeration type,
6535 integral promotions (_conv.prom_) and integral conversions
6536 (_conv.integral_) are applied. */
6538 {
6540 {
6545 }
6550 /* Notice that there are constant expressions like '4 % 0' which
6551 do not fold into integer constants. */
6554 {
6556 {
6560 else
6566 /* else cxx_constant_value complained but gave us
6567 a real constant, so go ahead. */
6569 }
6570 else
6572 }
6574 /* Avoid typedef problems. */
6577 }
6578 /* [temp.arg.nontype]/5, bullet 2
6580 For a non-type template-parameter of type pointer to object,
6581 qualification conversions (_conv.qual_) and the array-to-pointer
6582 conversion (_conv.array_) are applied. */
6584 {
6587 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6588 decay_conversion or an explicit cast. If it's a problematic cast,
6589 we'll complain about it below. */
6591 {
6596 {
6599 }
6600 }
6602 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6604 A template-argument for a non-type, non-template template-parameter
6605 shall be one of: [...]
6607 -- the name of a non-type template-parameter;
6608 -- the address of an object or function with external linkage, [...]
6609 expressed as "& id-expression" where the & is optional if the name
6610 refers to a function or array, or if the corresponding
6611 template-parameter is a reference.
6613 Here, we do not care about functions, as they are invalid anyway
6614 for a parameter of type pointer-to-object. */
6617 /* Non-type template parameters are OK. */
6618 ;
6622 {
6624 {
6627 "because %qD is a variable, not the address of "
6630 }
6632 {
6638 }
6639 /* Other values, like integer constants, might be valid
6640 non-type arguments of some other type. */
6642 }
6643 else
6644 {
6648 {
6653 }
6655 {
6661 }
6664 {
6669 }
6670 /* C++17: For a non-type template-parameter of reference or pointer
6671 type, the value of the constant expression shall not refer to (or
6672 for a pointer type, shall not be the address of):
6673 * a subobject (4.5),
6674 * a temporary object (15.2),
6675 * a string literal (5.13.5),
6676 * the result of a typeid expression (8.2.8), or
6677 * a predefined __func__ variable (11.4.1). */
6679 {
6682 decl);
6684 }
6688 {
6693 }
6695 {
6699 decl);
6701 }
6702 }
6709 }
6710 /* [temp.arg.nontype]/5, bullet 3
6712 For a non-type template-parameter of type reference to object, no
6713 conversions apply. The type referred to by the reference may be more
6714 cv-qualified than the (otherwise identical) type of the
6715 template-argument. The template-parameter is bound directly to the
6716 template-argument, which must be an lvalue. */
6718 {
6720 expr_type))
6724 {
6729 }
6732 {
6737 }
6739 /* [temp.arg.nontype]/1
6741 A template-argument for a non-type, non-template template-parameter
6742 shall be one of: [...]
6744 -- the address of an object or function with external linkage. */
6747 {
6750 {
6753 "because a reference variable does not have a constant "
6756 }
6757 }
6761 /* OK, dependent reference. We don't want to ask whether a DECL is
6763 else
6764 {
6766 {
6772 }
6774 /* DR 1155 allows internal linkage in C++11 and up. */
6777 {
6783 }
6786 }
6790 }
6791 /* [temp.arg.nontype]/5, bullet 4
6793 For a non-type template-parameter of type pointer to function, only
6794 the function-to-pointer conversion (_conv.func_) is applied. If the
6795 template-argument represents a set of overloaded functions (or a
6796 pointer to such), the matching function is selected from the set
6797 (_over.over_). */
6799 {
6800 /* If the argument is a template-id, we might not have enough
6801 context information to decay the pointer. */
6803 {
6807 }
6810 /* Null pointer values are OK in C++11. */
6816 }
6817 /* [temp.arg.nontype]/5, bullet 5
6819 For a non-type template-parameter of type reference to function, no
6820 conversions apply. If the template-argument represents a set of
6821 overloaded functions, the matching function is selected from the set
6822 (_over.over_). */
6824 {
6826 {
6828 {
6833 }
6835 }
6840 }
6841 /* [temp.arg.nontype]/5, bullet 6
6843 For a non-type template-parameter of type pointer to member function,
6844 no conversions apply. If the template-argument represents a set of
6845 overloaded member functions, the matching member function is selected
6846 from the set (_over.over_). */
6848 {
6853 /* [temp.arg.nontype] bullet 1 says the pointer to member
6854 expression must be a pointer-to-member constant. */
6859 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6860 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6863 }
6864 /* [temp.arg.nontype]/5, bullet 7
6866 For a non-type template-parameter of type pointer to data member,
6867 qualification conversions (_conv.qual_) are applied. */
6869 {
6870 /* [temp.arg.nontype] bullet 1 says the pointer to member
6871 expression must be a pointer-to-member constant. */
6879 }
6881 {
6883 {
6888 }
6890 }
6891 /* A template non-type parameter must be one of the above. */
6892 else
6895 /* Sanity check: did we actually convert the argument to the
6896 right type? */
6900 }
6902 /* Subroutine of coerce_template_template_parms, which returns 1 if
6903 PARM_PARM and ARG_PARM match using the rule for the template
6904 parameters of template template parameters. Both PARM and ARG are
6905 template parameters; the rest of the arguments are the same as for
6906 coerce_template_template_parms.
6907 */
6908 static int
6910 tree arg,
6911 tsubst_flags_t complain,
6912 tree in_decl,
6913 tree outer_args)
6914 {
6923 {
6925 /* We encounter instantiations of templates like
6926 template <template <template <class> class> class TT>
6927 class C; */
6928 {
6935 }
6936 /* Fall through. */
6941 /* Argument is a parameter pack but parameter is not. */
6946 /* The tsubst call is used to handle cases such as
6948 template <int> class C {};
6949 template <class T, template <T> class TT> class D {};
6950 D<int, C> d;
6952 i.e. the parameter list of TT depends on earlier parameters. */
6954 {
6959 }
6963 /* Argument is a parameter pack but parameter is not. */
6970 }
6973 }
6975 /* Coerce template argument list ARGLIST for use with template
6976 template-parameter TEMPL. */
6978 static tree
6980 tsubst_flags_t complain)
6981 {
6982 /* Consider an example where a template template parameter declared as
6984 template <class T, class U = std::allocator<T> > class TT
6986 The template parameter level of T and U are one level larger than
6987 of TT. To proper process the default argument of U, say when an
6988 instantiation `TT<int>' is seen, we need to build the full
6989 arguments containing {int} as the innermost level. Outer levels,
6990 available when not appearing as default template argument, can be
6991 obtained from the arguments of the enclosing template.
6993 Suppose that TT is later substituted with std::vector. The above
6994 instantiation is `TT<int, std::allocator<T> >' with TT at
6995 level 1, and T at level 2, while the template arguments at level 1
6996 becomes {std::vector} and the inner level 2 is {int}. */
7000 {
7002 /* We want arguments for the partial specialization, not arguments for
7003 the primary template. */
7005 else
7007 }
7009 {
7010 /* This is an argument of the current template, so we haven't set
7011 DECL_CONTEXT yet. */
7012 tree relevant_template_parms;
7014 /* Parameter levels that are greater than the level of the given
7015 template template parm are irrelevant. */
7022 }
7029 complain,
7032 }
7034 /* A cache of template template parameters with match-all default
7035 arguments. */
7037 static void
7039 {
7043 }
7044 static tree
7046 {
7051 }
7053 /* T is a bound template template-parameter. Copy its arguments into default
7054 arguments of the template template-parameter's template parameters. */
7056 static tree
7058 {
7081 {
7084 {
7087 }
7088 }
7092 }
7094 /* ARG is a bound potential template template-argument, and PARGS is a list
7095 of arguments for the corresponding template template-parameter. Adjust
7096 PARGS as appropriate for application to ARG's template, and if ARG is a
7097 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7098 arguments to the template template parameter. */
7100 static tree
7102 {
7106 {
7107 /* When comparing two template template-parameters in partial ordering,
7108 rewrite the one currently being used as an argument to have default
7109 arguments for all parameters. */
7115 }
7116 else
7117 {
7118 tree aparms
7123 }
7126 }
7128 /* Subroutine of unify for the case when PARM is a
7129 BOUND_TEMPLATE_TEMPLATE_PARM. */
7131 static int
7134 {
7138 /* The template template parm might be variadic and the argument
7139 not, so flatten both argument lists. */
7144 {
7145 /* In keeping with P0522R0, adjust P's template arguments
7146 to apply to A's template; then flatten it again. */
7155 /* If the P0522 adjustment eliminated a pack expansion, deduce
7156 empty packs. */
7162 }
7163 else
7164 {
7165 /* Deduce arguments T, i from TT<T> or TT<i>.
7166 We check each element of PARMVEC and ARGVEC individually
7167 rather than the whole TREE_VEC since they can have
7168 different number of elements, which is allowed under N2555. */
7172 /* Check if the parameters end in a pack, making them
7173 variadic. */
7180 /* If the template argument list of P contains a pack
7181 expansion that is not the last template argument, the
7182 entire template argument list is a non-deduced
7183 context. */
7201 DEDUCE_EXACT,
7204 }
7207 }
7209 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7210 template template parameters. Both PARM_PARMS and ARG_PARMS are
7211 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7212 or PARM_DECL.
7214 Consider the example:
7215 template <class T> class A;
7216 template<template <class U> class TT> class B;
7218 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7219 the parameters to A, and OUTER_ARGS contains A. */
7221 static int
7223 tree arg_parms,
7224 tsubst_flags_t complain,
7225 tree in_decl,
7226 tree outer_args)
7227 {
7239 {
7240 /* P0522R0: A template template-parameter P is at least as specialized as
7241 a template template-argument A if, given the following rewrite to two
7242 function templates, the function template corresponding to P is at
7243 least as specialized as the function template corresponding to A
7244 according to the partial ordering rules for function templates
7245 ([temp.func.order]). Given an invented class template X with the
7246 template parameter list of A (including default arguments):
7248 * Each of the two function templates has the same template parameters,
7249 respectively, as P or A.
7251 * Each function template has a single function parameter whose type is
7252 a specialization of X with template arguments corresponding to the
7253 template parameters from the respective function template where, for
7254 each template parameter PP in the template parameter list of the
7255 function template, a corresponding template argument AA is formed. If
7256 PP declares a parameter pack, then AA is the pack expansion
7257 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7259 If the rewrite produces an invalid type, then P is not at least as
7260 specialized as A. */
7262 /* So coerce P's args to apply to A's parms, and then deduce between A's
7263 args and the converted args. If that succeeds, A is at least as
7264 specialized as P, so they match.*/
7271 {
7277 }
7278 }
7280 /* Determine whether we have a parameter pack at the end of the
7281 template template parameter's template parameter list. */
7283 {
7290 {
7304 }
7305 }
7311 /* Check all of the template parameters except the parameter pack at
7312 the end (if any). */
7314 {
7323 outer_args))
7326 }
7329 {
7330 /* Check each of the template parameters in the template
7331 argument against the template parameter pack at the end of
7332 the template template parameter. */
7339 {
7346 outer_args))
7348 }
7349 }
7352 }
7354 /* Verifies that the deduced template arguments (in TARGS) for the
7355 template template parameters (in TPARMS) represent valid bindings,
7356 by comparing the template parameter list of each template argument
7357 to the template parameter list of its corresponding template
7358 template parameter, in accordance with DR150. This
7359 routine can only be called after all template arguments have been
7360 deduced. It will return TRUE if all of the template template
7361 parameter bindings are okay, FALSE otherwise. */
7362 bool
7364 {
7368 /* We're dealing with template parms in this process. */
7374 {
7379 {
7384 {
7385 /* Look inside the argument pack. */
7388 }
7391 {
7395 /* Extract the next argument from the argument
7396 pack. */
7400 /* Look at the pattern of the pack expansion. */
7403 /* Extract the template parameters from the template
7404 argument. */
7410 /* Verify that we can coerce the template template
7411 parameters from the template argument to the template
7412 parameter. This requires an exact match. */
7414 && !coerce_template_template_parms
7416 targ_parms,
7417 tf_none,
7418 tparm,
7419 targs))
7420 {
7423 }
7424 }
7425 }
7426 }
7428 out:
7432 }
7434 /* Since type attributes aren't mangled, we need to strip them from
7435 template type arguments. */
7437 static tree
7439 {
7449 }
7451 /* And from inside dependent non-type arguments like sizeof(Type). */
7453 static tree
7455 {
7465 }
7467 // A template declaration can be substituted for a constrained
7468 // template template parameter only when the argument is more
7469 // constrained than the parameter.
7470 static bool
7472 {
7475 /* For now, allow constrained template template arguments
7476 and unconstrained template template parameters. */
7482 // If the template parameter is constrained, we need to rewrite its
7483 // constraints in terms of the ARG's template parameters. This ensures
7484 // that all of the template parameter types will have the same depth.
7485 //
7486 // Note that this is only valid when coerce_template_template_parm is
7487 // true for the innermost template parameters of PARM and ARG. In other
7488 // words, because coercion is successful, this conversion will be valid.
7490 {
7497 }
7500 }
7502 // Convert a placeholder argument into a binding to the original
7503 // parameter. The original parameter is saved as the TREE_TYPE of
7504 // ARG.
7507 {
7510 }
7512 /* Convert the indicated template ARG as necessary to match the
7513 indicated template PARM. Returns the converted ARG, or
7514 error_mark_node if the conversion was unsuccessful. Error and
7515 warning messages are issued under control of COMPLAIN. This
7516 conversion is for the Ith parameter in the parameter list. ARGS is
7517 the full set of template arguments deduced so far. */
7519 static tree
7521 tree arg,
7522 tree args,
7523 tsubst_flags_t complain,
7525 tree in_decl)
7526 {
7527 tree orig_arg;
7528 tree val;
7534 /* Trivially convert placeholders. */
7543 {
7544 /* The template argument was the name of some
7545 member function. That's usually
7546 invalid, but static members are OK. In any
7547 case, grab the underlying fields/functions
7548 and issue an error later if required. */
7551 }
7559 /* When determining whether an argument pack expansion is a template,
7560 look at the pattern. */
7564 /* Deal with an injected-class-name used as a template template arg. */
7566 {
7569 {
7579 }
7580 }
7582 is_tmpl_type =
7598 {
7600 {
7604 }
7607 "to refer to a type member of a template parameter, "
7612 typename_type,
7613 complain);
7616 }
7618 {
7620 {
7622 {
7634 else
7637 }
7638 }
7640 }
7642 {
7644 {
7651 else
7654 }
7656 }
7659 /* We already did the appropriate conversion when packing args. */
7662 {
7664 {
7666 /* The number of argument required is not known yet.
7667 Just accept it for now. */
7669 else
7670 {
7672 tree argparm;
7674 /* Strip alias templates that are equivalent to another
7675 template. */
7681 args))
7682 {
7685 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7686 TEMPLATE_DECL. */
7688 {
7693 }
7694 }
7695 else
7696 {
7698 {
7705 }
7708 }
7710 // Check that the constraints are compatible before allowing the
7711 // substitution.
7714 {
7716 {
7722 }
7724 }
7725 }
7726 }
7727 else
7729 /* We only form one instance of each template specialization.
7730 Therefore, if we use a non-canonical variant (i.e., a
7731 typedef), any future messages referring to the type will use
7732 the typedef, which is confusing if those future uses do not
7733 themselves also use the typedef. */
7736 }
7737 else
7738 {
7742 {
7746 }
7747 else
7755 /* We used to call digest_init here. However, digest_init
7756 will report errors, which we don't want when complain
7757 is zero. More importantly, digest_init will try too
7758 hard to convert things: for example, `0' should not be
7759 converted to pointer type at this point according to
7760 the standard. Accepting this is not merely an
7761 extension, since deciding whether or not these
7762 conversions can occur is part of determining which
7763 function template to call, or whether a given explicit
7764 argument specification is valid. */
7766 else
7776 {
7777 /* Reject template arguments that are references to built-in
7778 functions with no library fallbacks. */
7787 }
7790 {
7791 /* Strip typedefs from the SCOPE_REF. */
7794 complain);
7797 }
7798 }
7801 }
7803 /* Coerces the remaining template arguments in INNER_ARGS (from
7804 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7805 Returns the coerced argument pack. PARM_IDX is the position of this
7806 parameter in the template parameter list. ARGS is the original
7807 template argument list. */
7808 static tree
7811 tree args,
7812 tree inner_args,
7814 tree new_args,
7816 tree in_decl,
7817 tsubst_flags_t complain)
7818 {
7821 tree packed_args;
7822 tree argument_pack;
7829 {
7830 /* When the template parameter is a non-type template parameter pack
7831 or template template parameter pack whose type or template
7832 parameters use parameter packs, we know exactly how many arguments
7833 we are looking for. Build a vector of the instantiated decls for
7834 these template parameters in PACKED_PARMS. */
7835 /* We can't use make_pack_expansion here because it would interpret a
7836 _DECL as a use rather than a declaration. */
7850 /* If we're doing a partial instantiation of a member template,
7851 verify that all of the types used for the non-type
7852 template parameter pack are, in fact, valid for non-type
7853 template parameters. */
7856 {
7859 {
7863 }
7864 /* We don't know how many args we have yet, just
7865 use the unconverted ones for now. */
7867 }
7870 }
7871 /* Check if we have a placeholder pack, which indicates we're
7872 in the context of a introduction list. In that case we want
7873 to match this pack to the single placeholder. */
7877 {
7880 }
7881 else
7884 /* Convert the remaining arguments, which will be a part of the
7885 parameter pack "parm". */
7888 {
7894 {
7895 /* Once we've packed as many args as we have types, stop. */
7899 /* We don't know how many args we have yet, just
7900 use the unconverted ones for now. */
7902 else
7904 }
7907 {
7910 }
7911 else
7914 in_decl);
7918 }
7922 {
7927 }
7932 else
7933 {
7936 }
7943 }
7945 /* Returns the number of pack expansions in the template argument vector
7946 ARGS. */
7948 static int
7950 {
7955 {
7959 }
7961 }
7963 /* Convert all template arguments to their appropriate types, and
7964 return a vector containing the innermost resulting template
7965 arguments. If any error occurs, return error_mark_node. Error and
7966 warning messages are issued under control of COMPLAIN.
7968 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7969 for arguments not specified in ARGS. Otherwise, if
7970 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7971 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7972 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7973 ARGS. */
7975 static tree
7977 tree args,
7978 tree in_decl,
7979 tsubst_flags_t complain,
7982 {
7984 tree orig_inner_args;
7985 tree inner_args;
7986 tree new_args;
7987 tree new_inner_args;
7991 /* When used as a boolean value, indicates whether this is a
7992 variadic template parameter list. Since it's an int, we can also
7993 subtract it from nparms to get the number of non-variadic
7994 parameters. */
7999 /* Likewise for parameters with default arguments. */
8007 /* Determine if there are any parameter packs or default arguments. */
8009 {
8017 }
8020 /* If there are no parameters that follow a parameter pack, we need to
8021 expand any argument packs so that we can deduce a parameter pack from
8022 some non-packed args followed by an argument pack, as in variadic85.C.
8023 If there are such parameters, we need to leave argument packs intact
8024 so the arguments are assigned properly. This can happen when dealing
8025 with a nested class inside a partial specialization of a class
8026 template, as in variadic92.C, or when deducing a template parameter pack
8027 from a sub-declarator, as in variadic114.C. */
8031 /* Count any pack expansion args. */
8037 && require_all_args
8038 && !variadic_args_p
8039 && (!use_default_args
8042 {
8044 {
8046 {
8050 }
8051 else
8058 }
8061 }
8062 /* We can't pass a pack expansion to a non-pack parameter of an alias
8063 template (DR 1430). */
8067 && variadic_args_p
8069 {
8071 {
8073 {
8079 {
8082 "pack expansion argument for non-pack parameter "
8084 else
8086 "pack expansion argument for non-pack parameter "
8090 }
8091 }
8093 found:;
8094 }
8096 }
8098 /* We need to evaluate the template arguments, even though this
8099 template-id may be nested within a "sizeof". */
8108 {
8109 tree arg;
8110 tree parm;
8112 /* Get the Ith template parameter. */
8116 {
8119 }
8121 /* Calculate the next argument. */
8124 else
8129 {
8130 /* Some arguments will be placed in the
8131 template parameter pack PARM. */
8138 {
8139 /* We don't know how many args we have yet, just use the
8140 unconverted (and still packed) ones for now. */
8144 }
8148 /* Store this argument. */
8150 {
8151 lost++;
8152 /* We are done with all of the arguments. */
8154 }
8155 else
8156 {
8159 }
8162 }
8164 {
8166 {
8167 /* "If every valid specialization of a variadic template
8168 requires an empty template parameter pack, the template is
8169 ill-formed, no diagnostic required." So check that the
8170 pattern works with this parameter. */
8175 in_decl);
8177 {
8182 }
8184 /* Recover from missing typename. */
8188 /* We don't know how many args we have yet, just
8189 use the unconverted ones for now. */
8193 }
8194 }
8196 {
8197 /* There must be a default arg in this case. */
8200 /* The position of the first default template argument,
8201 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8202 Record that. */
8206 }
8207 else
8211 {
8214 }
8216 /* This only occurs if there was an error in the template
8217 parameter list itself (which we would already have
8218 reported) that we are trying to recover from, e.g., a class
8219 template with a parameter list such as
8220 template<typename..., typename>. */
8222 else
8228 lost++;
8230 }
8235 {
8237 {
8242 }
8244 }
8254 }
8256 /* Convert all template arguments to their appropriate types, and
8257 return a vector containing the innermost resulting template
8258 arguments. If any error occurs, return error_mark_node. Error and
8259 warning messages are not issued.
8261 Note that no function argument deduction is performed, and default
8262 arguments are used to fill in unspecified arguments. */
8263 tree
8265 {
8267 }
8269 /* Convert all template arguments to their appropriate type, and
8270 instantiate default arguments as needed. This returns a vector
8271 containing the innermost resulting template arguments, or
8272 error_mark_node if unsuccessful. */
8273 tree
8275 tsubst_flags_t complain)
8276 {
8278 }
8280 /* Like coerce_template_parms. If PARMS represents all template
8281 parameters levels, this function returns a vector of vectors
8282 representing all the resulting argument levels. Note that in this
8283 case, only the innermost arguments are coerced because the
8284 outermost ones are supposed to have been coerced already.
8286 Otherwise, if PARMS represents only (the innermost) vector of
8287 parameters, this function returns a vector containing just the
8288 innermost resulting arguments. */
8290 static tree
8292 tree args,
8293 tree in_decl,
8294 tsubst_flags_t complain,
8297 {
8300 tree coerced_args;
8303 {
8305 tree level;
8311 {
8312 tree l;
8316 require_all_args,
8317 use_default_args);
8318 else
8325 }
8326 }
8327 else
8330 require_all_args,
8331 use_default_args);
8333 }
8335 /* Returns 1 if template args OT and NT are equivalent. */
8337 int
8339 {
8348 /* For member templates */
8357 {
8374 }
8378 {
8381 /* Don't treat an alias template specialization with dependent
8382 arguments as equivalent to its underlying type when used as a
8383 template argument; we need them to be distinct so that we
8384 substitute into the specialization arguments at instantiation
8385 time. And aliases can't be equivalent without being ==, so
8386 we don't need to look any deeper.
8388 During partial ordering, however, we need to treat them normally so
8389 that we can order uses of the same alias with different
8390 cv-qualification (79960). */
8394 else
8396 }
8399 else
8400 {
8401 /* Try to treat a template non-type argument that has been converted
8402 to the parameter type as equivalent to one that hasn't yet. */
8415 }
8416 }
8418 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8419 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8420 NEWARG_PTR with the offending arguments if they are non-NULL. */
8422 int
8426 {
8439 {
8444 {
8450 }
8451 }
8453 }
8457 {
8459 }
8461 static void
8463 {
8473 /* We are called both from instantiate_decl, where we've already had a
8474 tinst_level pushed, and instantiate_template, where we haven't.
8475 Compensate. */
8486 else
8495 }
8498 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8499 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8500 documentation for TEMPLATE_ID_EXPR. */
8502 tree
8504 {
8505 tree type;
8513 {
8516 }
8519 {
8521 unknown_type_node,
8523 arglist);
8525 }
8532 }
8534 /* Within the scope of a template class S<T>, the name S gets bound
8535 (in build_self_reference) to a TYPE_DECL for the class, not a
8536 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8537 or one of its enclosing classes, and that type is a template,
8538 return the associated TEMPLATE_DECL. Otherwise, the original
8539 DECL is returned.
8541 Also handle the case when DECL is a TREE_LIST of ambiguous
8542 injected-class-names from different bases. */
8544 tree
8546 {
8550 /* DR 176: A lookup that finds an injected-class-name (10.2
8551 [class.member.lookup]) can result in an ambiguity in certain cases
8552 (for example, if it is found in more than one base class). If all of
8553 the injected-class-names that are found refer to specializations of
8554 the same class template, and if the name is followed by a
8555 template-argument-list, the reference refers to the class template
8556 itself and not a specialization thereof, and is not ambiguous. */
8558 {
8561 {
8567 }
8570 else
8572 }
8578 }
8580 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8581 parameters, find the desired type.
8583 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8585 IN_DECL, if non-NULL, is the template declaration we are trying to
8586 instantiate.
8588 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8589 the class we are looking up.
8591 Issue error and warning messages under control of COMPLAIN.
8593 If the template class is really a local class in a template
8594 function, then the FUNCTION_CONTEXT is the function in which it is
8595 being instantiated.
8597 ??? Note that this function is currently called *twice* for each
8598 template-id: the first time from the parser, while creating the
8599 incomplete type (finish_template_type), and the second type during the
8600 real instantiation (instantiate_template_class). This is surely something
8601 that we want to avoid. It also causes some problems with argument
8602 coercion (see convert_nontype_argument for more information on this). */
8604 static tree
8607 {
8609 tree t;
8612 spec_entry elt;
8613 hashval_t hash;
8616 {
8620 else
8621 {
8628 }
8631 }
8633 {
8636 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8637 an implicit typename for the second A. Deal with it. */
8642 {
8645 }
8646 }
8649 {
8652 }
8654 {
8658 }
8660 {
8663 }
8665 /* Issue an error message if we didn't find a template. */
8667 {
8671 }
8674 /* Make sure it's a user visible template, if it was named by
8675 the user. */
8678 {
8680 {
8684 }
8686 }
8690 /* An alias that just changes the name of a template is equivalent to the
8691 other template, so if any of the arguments are pack expansions, strip
8692 the alias to avoid problems with a pack expansion passed to a non-pack
8693 alias template parameter (DR 1430). */
8698 {
8699 tree parm;
8708 }
8709 else
8710 {
8712 tree gen_tmpl;
8713 tree type_decl;
8721 /* An error occurred while building the template TEMPL, and a
8722 diagnostic has most certainly been emitted for that
8723 already. Let's propagate that error. */
8732 {
8733 /* We've been given an incomplete set of template arguments.
8734 For example, given:
8736 template <class T> struct S1 {
8737 template <class U> struct S2 {};
8738 template <class U> struct S2<U*> {};
8739 };
8741 we will be called with an ARGLIST of `U*', but the
8742 TEMPLATE will be `template <class T> template
8743 <class U> struct S1<T>::S2'. We must fill in the missing
8744 arguments. */
8748 }
8750 /* Now we should have enough arguments. */
8753 /* From here on, we're only interested in the most general
8754 template. */
8756 /* Calculate the BOUND_ARGS. These will be the args that are
8757 actually tsubst'd into the definition to create the
8758 instantiation. */
8760 complain,
8765 /* We were unable to bind the arguments. */
8768 /* In the scope of a template class, explicit references to the
8769 template class refer to the type of the template, not any
8770 instantiation of it. For example, in:
8772 template <class T> class C { void f(C<T>); }
8774 the `C<T>' is just the same as `C'. Outside of the
8775 class, however, such a reference is an instantiation. */
8779 {
8784 }
8786 /* If we already have this specialization, return it. */
8796 /* If the the template's constraints are not satisfied,
8797 then we cannot form a valid type.
8799 Note that the check is deferred until after the hash
8800 lookup. This prevents redundant checks on previously
8801 instantiated specializations. */
8803 {
8805 {
8808 }
8810 }
8814 /* If the deduced arguments are invalid, then the binding
8815 failed. */
8819 complain))
8826 {
8831 }
8841 /* Create the type. */
8843 {
8844 /* The user referred to a specialization of an alias
8845 template represented by GEN_TMPL.
8847 [temp.alias]/2 says:
8849 When a template-id refers to the specialization of an
8850 alias template, it is equivalent to the associated
8851 type obtained by substitution of its
8852 template-arguments for the template-parameters in the
8853 type-id of the alias template. */
8856 /* Note that the call above (by indirectly calling
8857 register_specialization in tsubst_decl) registers the
8858 TYPE_DECL representing the specialization of the alias
8859 template. So next time someone substitutes ARGLIST for
8860 the template parms into the alias template (GEN_TMPL),
8861 she'll get that TYPE_DECL back. */
8865 }
8867 {
8869 {
8880 }
8881 else
8882 {
8883 /* We don't want to call start_enum for this type, since
8884 the values for the enumeration constants may involve
8885 template parameters. And, no one should be interested
8886 in the enumeration constants for such a type. */
8889 }
8893 }
8895 {
8901 /* A local class. Make sure the decl gets registered properly. */
8906 /* This instantiation is another name for the primary
8907 template type. Set the TYPE_CANONICAL field
8908 appropriately. */
8911 /* Some of the template arguments require structural
8912 equality testing, so this template class requires
8913 structural equality testing. */
8915 }
8916 else
8919 /* If we called start_enum or pushtag above, this information
8920 will already be set up. */
8922 {
8929 }
8930 else
8934 {
8940 {
8943 }
8944 }
8948 {
8952 {
8953 tree attributes
8961 }
8962 }
8964 /* Let's consider the explicit specialization of a member
8965 of a class template specialization that is implicitly instantiated,
8966 e.g.:
8967 template<class T>
8968 struct S
8969 {
8970 template<class U> struct M {}; //#0
8971 };
8973 template<>
8974 template<>
8975 struct S<int>::M<char> //#1
8976 {
8977 int i;
8978 };
8979 [temp.expl.spec]/4 says this is valid.
8981 In this case, when we write:
8982 S<int>::M<char> m;
8984 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8985 the one of #0.
8987 When we encounter #1, we want to store the partial instantiation
8988 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8990 For all cases other than this "explicit specialization of member of a
8991 class template", we just want to store the most general template into
8992 the CLASSTYPE_TI_TEMPLATE of M.
8994 This case of "explicit specialization of member of a class template"
8995 only happens when:
8996 1/ the enclosing class is an instantiation of, and therefore not
8997 the same as, the context of the most general template, and
8998 2/ we aren't looking at the partial instantiation itself, i.e.
8999 the innermost arguments are not the same as the innermost parms of
9000 the most general template.
9002 So it's only when 1/ and 2/ happens that we want to use the partial
9003 instantiation of the member template in lieu of its most general
9004 template. */
9008 /* the enclosing class must be an instantiation... */
9011 {
9015 tree partial_inst_args =
9022 use_partial_inst_tmpl =
9023 /*...and we must not be looking at the partial instantiation
9024 itself. */
9026 partial_inst_args);
9027 }
9030 /* This case is easy; there are no member templates involved. */
9032 else
9033 {
9034 /* This is a full instantiation of a member template. Find
9035 the partial instantiation of which this is an instance. */
9037 /* Temporarily reduce by one the number of levels in the ARGLIST
9038 so as to avoid comparing the last set of arguments. */
9042 /* FOUND is either a proper class type, or an alias
9043 template specialization. In the later case, it's a
9044 TYPE_DECL, resulting from the substituting of arguments
9045 for parameters in the TYPE_DECL of the alias template
9046 done earlier. So be careful while getting the template
9047 of FOUND. */
9049 ? found
9053 }
9055 // Build template info for the new specialization.
9064 /* Note this use of the partial instantiation so we can check it
9065 later in maybe_process_partial_specialization. */
9072 /* Now that the type has been registered on the instantiations
9073 list, we set up the enumerators. Because the enumeration
9074 constants may involve the enumeration type itself, we make
9075 sure to register the type first, and then create the
9076 constants. That way, doing tsubst_expr for the enumeration
9077 constants won't result in recursive calls here; we'll find
9078 the instantiation and exit above. */
9082 /* If the type makes use of template parameters, the
9083 code that generates debugging information will crash. */
9086 /* Possibly limit visibility based on template args. */
9093 }
9094 }
9096 /* Wrapper for lookup_template_class_1. */
9098 tree
9101 {
9102 tree ret;
9108 }
9110 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9112 tree
9114 {
9115 /* The type of the expression is NULL_TREE since the template-id could refer
9116 to an explicit or partial specialization. */
9119 /* Except that concepts are always bool. */
9122 }
9124 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9126 tree
9128 {
9132 /* We never want to return a VAR_DECL for a variable concept, since they
9133 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9148 {
9150 {
9153 }
9155 }
9157 /* If a template-id refers to a specialization of a variable
9158 concept, then the expression is true if and only if the
9159 concept's constraints are satisfied by the given template
9160 arguments.
9162 NOTE: This is an extension of Concepts Lite TS that
9163 allows constraints to be used in expressions. */
9165 {
9168 }
9171 }
9173 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9174 TARGS template args, and instantiate it if it's not dependent. */
9176 tree
9178 tsubst_flags_t complain)
9179 {
9182 {
9185 }
9188 }
9190 \f
9191 struct pair_fn_data
9192 {
9193 tree_fn_t fn;
9194 tree_fn_t any_fn;
9196 /* True when we should also visit template parameters that occur in
9197 non-deduced contexts. */
9200 };
9202 /* Called from for_each_template_parm via walk_tree. */
9204 static tree
9206 {
9213 #define WALK_SUBTREE(NODE) \
9214 do \
9215 { \
9216 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9217 pfd->include_nondeduced_p, \
9218 pfd->any_fn); \
9219 if (result) goto out; \
9220 } \
9221 while (0)
9231 {
9235 /* Fall through. */
9241 else
9251 /* Since we're not going to walk subtrees, we have to do this
9252 explicitly here. */
9254 /* Fall through. */
9257 /* Check the return type. */
9260 /* Check the parameter types. Since default arguments are not
9261 instantiated until they are needed, the TYPE_ARG_TYPES may
9262 contain expressions that involve template parameters. But,
9263 no-one should be looking at them yet. And, once they're
9264 instantiated, they don't contain template parameters, so
9265 there's no point in looking at them then, either. */
9266 {
9267 tree parm;
9272 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9273 want walk_tree walking into them itself. */
9275 }
9278 {
9282 }
9299 /* Fall through. */
9311 /* Record template parameters such as `T' inside `TT<T>'. */
9313 /* Fall through. */
9325 /* A template template parameter is encountered. */
9329 /* Already substituted template template parameter */
9334 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9335 partial instantiation. */
9347 /* If there's no type, then this thing must be some expression
9348 involving template parameters. */
9370 }
9372 #undef WALK_SUBTREE
9374 /* We didn't find any template parameters we liked. */
9375 out:
9377 }
9379 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9380 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9381 call FN with the parameter and the DATA.
9382 If FN returns nonzero, the iteration is terminated, and
9383 for_each_template_parm returns 1. Otherwise, the iteration
9384 continues. If FN never returns a nonzero value, the value
9385 returned by for_each_template_parm is 0. If FN is NULL, it is
9386 considered to be the function which always returns 1.
9388 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9389 parameters that occur in non-deduced contexts. When false, only
9390 visits those template parameters that can be deduced. */
9392 static tree
9396 tree_fn_t any_fn)
9397 {
9399 tree result;
9401 /* Set up. */
9407 /* Walk the tree. (Conceptually, we would like to walk without
9408 duplicates, but for_each_template_parm_r recursively calls
9409 for_each_template_parm, so we would need to reorganize a fair
9410 bit to use walk_tree_without_duplicates, so we keep our own
9411 visited list.) */
9414 else
9417 for_each_template_parm_r,
9421 /* Clean up. */
9423 {
9426 }
9429 }
9431 /* Returns true if T depends on any template parameter. */
9433 int
9435 {
9465 else
9466 {
9469 }
9474 }
9476 /* Returns true iff current_function_decl is an incompletely instantiated
9477 template. Useful instead of processing_template_decl because the latter
9478 is set to 0 during instantiate_non_dependent_expr. */
9480 bool
9482 {
9491 }
9493 /* Returns true if T depends on any template parameter with level LEVEL. */
9495 bool
9497 {
9500 }
9502 /* Returns true if the signature of DECL depends on any template parameter from
9503 its enclosing class. */
9505 bool
9507 {
9517 template_parm_outer_level,
9527 }
9529 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9530 ill-formed translation unit, i.e. a variable or function that isn't
9531 usable in a constant expression. */
9535 {
9539 }
9541 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9542 neglectable and instantiated from within an erroneous instantiation. */
9544 static bool
9546 {
9557 }
9565 /* We're starting to instantiate D; record the template instantiation context
9566 for diagnostics and to restore it later. */
9568 bool
9570 {
9572 }
9574 /* We're starting to instantiate D; record the template instantiation context
9575 at LOC for diagnostics and to restore it later. */
9577 bool
9579 {
9583 {
9584 /* Tell error.c not to try to instantiate any templates. */
9587 "template instantiation depth exceeds maximum of %d"
9589 max_tinst_depth);
9591 }
9593 /* If the current instantiation caused problems, don't let it instantiate
9594 anything else. Do allow deduction substitution and decls usable in
9595 constant expressions. */
9599 /* When not -quiet, dump template instantiations other than functions, since
9600 announce_function will take care of those. */
9619 }
9621 /* We're done instantiating this template; return to the instantiation
9622 context. */
9624 void
9626 {
9627 /* Restore the filename and line number stashed away when we started
9628 this instantiation. */
9632 }
9634 /* We're instantiating a deferred template; restore the template
9635 instantiation context in which the instantiation was requested, which
9636 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9638 static tree
9640 {
9652 }
9654 /* Returns the TINST_LEVEL which gives the original instantiation
9655 context. */
9659 {
9665 }
9667 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9668 vector of template arguments, as for tsubst.
9670 Returns an appropriate tsubst'd friend declaration. */
9672 static tree
9674 {
9675 tree new_friend;
9680 /* This was a friend declared with an explicit template
9681 argument list, e.g.:
9683 friend void f<>(T);
9685 to indicate that f was a template instantiation, not a new
9686 function declaration. Now, we have to figure out what
9687 instantiation of what template. */
9688 {
9690 tree new_args;
9691 tree tmpl;
9694 /* Friend functions are looked up in the containing namespace scope.
9695 We must enter that scope, to avoid finding member functions of the
9696 current class with same name. */
9711 tsk_none);
9713 }
9717 /* The NEW_FRIEND will look like an instantiation, to the
9718 compiler, but is not an instantiation from the point of view of
9719 the language. For example, we might have had:
9721 template <class T> struct S {
9722 template <class U> friend void f(T, U);
9723 };
9725 Then, in S<int>, template <class U> void f(int, U) is not an
9726 instantiation of anything. */
9732 {
9736 }
9738 /* The mangled name for the NEW_FRIEND is incorrect. The function
9739 is not a template instantiation and should not be mangled like
9740 one. Therefore, we forget the mangling here; we'll recompute it
9741 later if we need it. */
9743 {
9746 }
9749 {
9750 tree old_decl;
9751 tree new_friend_template_info;
9752 tree new_friend_result_template_info;
9753 tree ns;
9756 /* We must save some information from NEW_FRIEND before calling
9757 duplicate decls since that function will free NEW_FRIEND if
9758 possible. */
9760 new_friend_is_defn =
9765 {
9766 /* This declaration is a `primary' template. */
9769 new_friend_result_template_info
9771 }
9772 else
9775 /* Inside pushdecl_namespace_level, we will push into the
9776 current namespace. However, the friend function should go
9777 into the namespace of the template. */
9787 {
9788 /* This new friend declaration matched an existing
9789 declaration. For example, given:
9791 template <class T> void f(T);
9792 template <class U> class C {
9793 template <class T> friend void f(T) {}
9794 };
9796 the friend declaration actually provides the definition
9797 of `f', once C has been instantiated for some type. So,
9798 old_decl will be the out-of-class template declaration,
9799 while new_friend is the in-class definition.
9801 But, if `f' was called before this point, the
9802 instantiation of `f' will have DECL_TI_ARGS corresponding
9803 to `T' but not to `U', references to which might appear
9804 in the definition of `f'. Previously, the most general
9805 template for an instantiation of `f' was the out-of-class
9806 version; now it is the in-class version. Therefore, we
9807 run through all specialization of `f', adding to their
9808 DECL_TI_ARGS appropriately. In particular, they need a
9809 new set of outer arguments, corresponding to the
9810 arguments for this class instantiation.
9812 The same situation can arise with something like this:
9814 friend void f(int);
9815 template <class T> class C {
9816 friend void f(T) {}
9817 };
9819 when `C<int>' is instantiated. Now, `f(int)' is defined
9820 in the class. */
9823 /* On the other hand, if the in-class declaration does
9824 *not* provide a definition, then we don't want to alter
9825 existing definitions. We can just leave everything
9826 alone. */
9827 ;
9828 else
9829 {
9833 /* Overwrite whatever template info was there before, if
9834 any, with the new template information pertaining to
9835 the declaration. */
9839 {
9840 /* We should have called reregister_specialization in
9841 duplicate_decls. */
9846 /* Instantiate it if the global has already been used. */
9850 }
9851 else
9852 {
9853 tree t;
9855 /* Indicate that the old function template is a partial
9856 instantiation. */
9864 /* Reassign any specializations already in the hash table
9865 to the new more general template, and add the
9866 additional template args. */
9870 {
9872 spec_entry elt;
9884 register_specialization
9887 }
9889 }
9890 }
9892 /* The information from NEW_FRIEND has been merged into OLD_DECL
9893 by duplicate_decls. */
9895 }
9896 }
9897 else
9898 {
9902 /* In the code
9903 template <class T> class C {
9904 template <class U> friend void C1<U>::f (); // case 1
9905 friend void C2<T>::f (); // case 2
9906 };
9907 we only need to make sure CONTEXT is a complete type for
9908 case 2. To distinguish between the two cases, we note that
9909 CONTEXT of case 1 remains dependent type after tsubst while
9910 this isn't true for case 2. */
9920 {
9922 /* do_friend adds the TEMPLATE_DECL for any member friend
9923 template even if it isn't a member template, i.e.
9924 template <class T> friend A<T>::f();
9925 Look through it in that case. */
9929 /* Check to see that the declaration is really present, and,
9930 possibly obtain an improved declaration. */
9935 }
9936 }
9939 }
9941 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9942 template arguments, as for tsubst.
9944 Returns an appropriate tsubst'd friend type or error_mark_node on
9945 failure. */
9947 static tree
9949 {
9950 tree friend_type;
9951 tree tmpl;
9952 tree context;
9955 {
9958 }
9963 {
9966 else
9968 }
9970 /* Look for a class template declaration. We look for hidden names
9971 because two friend declarations of the same template are the
9972 same. For example, in:
9974 struct A {
9975 template <typename> friend class F;
9976 };
9977 template <typename> struct B {
9978 template <typename> friend class F;
9979 };
9981 both F templates are the same. */
9985 /* But, if we don't find one, it might be because we're in a
9986 situation like this:
9988 template <class T>
9989 struct S {
9990 template <class U>
9991 friend struct S;
9992 };
9994 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9995 for `S<int>', not the TEMPLATE_DECL. */
9997 {
10000 }
10003 {
10004 /* The friend template has already been declared. Just
10005 check to see that the declarations match, and install any new
10006 default parameters. We must tsubst the default parameters,
10007 of course. We only need the innermost template parameters
10008 because that is all that redeclare_class_template will look
10009 at. */
10012 {
10013 tree parms;
10014 location_t saved_input_location;
10024 }
10027 }
10028 else
10029 {
10030 /* The friend template has not already been declared. In this
10031 case, the instantiation of the template class will cause the
10032 injection of this template into the global scope. */
10037 /* The new TMPL is not an instantiation of anything, so we
10038 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
10039 the new type because that is supposed to be the corresponding
10040 template decl, i.e., TMPL. */
10047 /* Inject this template into the global scope. */
10049 }
10052 {
10055 else
10057 }
10060 }
10062 /* Returns zero if TYPE cannot be completed later due to circularity.
10063 Otherwise returns one. */
10065 static int
10067 {
10077 else
10079 }
10084 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10085 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10087 static tree
10090 {
10099 {
10106 clauses
10110 else
10112 }
10113 /* If the first attribute argument is an identifier, don't
10114 pass it through tsubst. Attributes like mode, format,
10115 cleanup and several target specific attributes expect it
10116 unmodified. */
10118 {
10119 tree chain
10124 }
10126 {
10127 /* An attribute pack expansion. */
10136 {
10140 }
10142 }
10143 else
10150 }
10152 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10153 unchanged or a new TREE_LIST chain. */
10155 static tree
10158 {
10163 {
10167 }
10171 {
10174 {
10177 {
10179 do
10184 }
10185 }
10187 }
10190 }
10192 /* Apply any attributes which had to be deferred until instantiation
10193 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10194 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10196 static void
10199 {
10201 tree t;
10208 {
10212 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10213 to our attributes parameter. */
10215 }
10216 else
10217 {
10219 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10220 lookup_template_class_1, and should be preserved. */
10224 }
10228 {
10232 }
10236 {
10241 {
10244 {
10248 do
10251 }
10252 else
10254 }
10257 }
10258 }
10260 /* Perform (or defer) access check for typedefs that were referenced
10261 from within the template TMPL code.
10262 This is a subroutine of instantiate_decl and instantiate_class_template.
10263 TMPL is the template to consider and TARGS is the list of arguments of
10264 that template. */
10266 static void
10268 {
10269 location_t saved_location;
10280 {
10292 /* Make access check error messages point to the location
10293 of the use of the typedef. */
10297 tf_warning_or_error);
10298 }
10300 }
10302 static tree
10304 {
10306 tree typedecl;
10307 tree pbinfo;
10308 tree base_list;
10310 tree fn_context;
10319 /* Figure out which template is being instantiated. */
10323 /* Determine what specialization of the original template to
10324 instantiate. */
10327 {
10330 }
10332 {
10333 /* This TYPE is actually an instantiation of a partial
10334 specialization. We replace the innermost set of ARGS with
10335 the arguments appropriate for substitution. For example,
10336 given:
10338 template <class T> struct S {};
10339 template <class T> struct S<T*> {};
10341 and supposing that we are instantiating S<int*>, ARGS will
10342 presently be {int*} -- but we need {int}. */
10345 }
10346 else
10347 {
10350 }
10352 /* If the template we're instantiating is incomplete, then clearly
10353 there's nothing we can do. */
10357 /* If we've recursively instantiated too many templates, stop. */
10361 /* Now we're really doing the instantiation. Mark the type as in
10362 the process of being defined. */
10365 /* We may be in the middle of deferred access check. Disable
10366 it now. */
10373 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10378 else
10379 {
10382 }
10383 /* Use #pragma pack from the template context. */
10389 /* Set the input location to the most specialized template definition.
10390 This is needed if tsubsting causes an error. */
10402 {
10405 /* Adjust visibility for template arguments. */
10407 }
10413 /* We should never instantiate a nested class before its enclosing
10414 class; we need to look up the nested class by name before we can
10415 instantiate it, and that lookup should instantiate the enclosing
10416 class. */
10422 {
10423 tree pbase_binfo;
10424 tree pushed_scope;
10427 /* We must enter the scope containing the type, as that is where
10428 the accessibility of types named in dependent bases are
10429 looked up from. */
10432 /* Substitute into each of the bases to determine the actual
10433 basetypes. */
10435 {
10436 tree base;
10442 {
10443 expanded_bases =
10450 }
10453 {
10455 /* Extract the already-expanded base class. */
10457 else
10458 /* Substitute to figure out the base class. */
10460 NULL_TREE);
10468 }
10469 }
10471 /* The list is now in reverse order; correct that. */
10476 }
10477 /* Now call xref_basetypes to set up all the base-class
10478 information. */
10486 /* Now that our base classes are set up, enter the scope of the
10487 class, so that name lookups into base classes, etc. will work
10488 correctly. This is precisely analogous to what we do in
10489 begin_class_definition when defining an ordinary non-template
10490 class, except we also need to push the enclosing classes. */
10493 /* Now members are processed in the order of declaration. */
10496 {
10500 {
10502 {
10503 /* Build new CLASSTYPE_NESTED_UTDS. */
10505 tree newtag;
10511 /* If the member is a class template, then -- even after
10512 substitution -- there may be dependent types in the
10513 template argument list for the class. We increment
10514 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10515 that function will assume that no types are dependent
10516 when outside of a template. */
10526 {
10530 /* Unfortunately, lookup_template_class sets
10531 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10532 instantiation (i.e., for the type of a member
10533 template class nested within a template class.)
10534 This behavior is required for
10535 maybe_process_partial_specialization to work
10536 correctly, but is not accurate in this case;
10537 the TAG is not an instantiation of anything.
10538 (The corresponding TEMPLATE_DECL is an
10539 instantiation, but the TYPE is not.) */
10542 /* Now, we call pushtag to put this NEWTAG into the scope of
10543 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10544 pushtag calling push_template_decl. We don't have to do
10545 this for enums because it will already have been done in
10546 tsubst_enum. */
10550 }
10551 }
10553 {
10554 tree r;
10563 /* Instantiate members marked with attribute used. */
10569 }
10572 /* A closure type for a lambda in a default argument for a
10573 member template. Ignore it; it will be instantiated with
10575 else
10576 {
10577 /* Build new TYPE_FIELDS. */
10579 {
10580 tree condition;
10583 condition =
10593 }
10595 {
10596 tree r;
10600 /* The file and line for this declaration, to
10601 assist in error message reporting. Since we
10602 called push_tinst_level above, we don't need to
10603 restore these. */
10613 {
10614 /* A capture pack became multiple fields. */
10617 }
10620 {
10624 {
10625 /* In [temp.inst]:
10627 [t]he initialization (and any associated
10628 side-effects) of a static data member does
10629 not occur unless the static data member is
10630 itself used in a way that requires the
10631 definition of the static data member to
10632 exist.
10634 Therefore, we do not substitute into the
10635 initialized for the static data member here. */
10636 finish_static_data_member_decl
10642 /* Instantiate members marked with attribute used. */
10645 }
10647 {
10648 /* Determine whether R has a valid type and can be
10649 completed later. If R is invalid, then its type
10650 is replaced by error_mark_node. */
10656 {
10657 /* If R's type couldn't be completed and
10658 it isn't a flexible array member (whose
10659 type is incomplete by definition) give
10660 an error. */
10663 }
10664 }
10666 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10667 such a thing will already have been added to the field
10668 list by tsubst_enum in finish_member_declaration in the
10669 CLASSTYPE_NESTED_UTDS case above. */
10673 {
10676 }
10677 }
10678 }
10679 }
10680 }
10681 else
10682 {
10685 {
10686 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10692 {
10693 /* template <class T> friend class C; */
10696 }
10698 {
10699 /* template <class T> friend class C::D; */
10705 }
10708 {
10709 /* This could be either
10711 friend class T::C;
10713 when dependent_type_p is false or
10715 template <class U> friend class T::C;
10717 otherwise. */
10718 /* Bump processing_template_decl in case this is something like
10719 template <class T> friend struct A<T>::B. */
10726 }
10729 {
10730 /* friend class C;
10732 where C hasn't been declared yet. Let's lookup name
10733 from namespace scope directly, bypassing any name that
10734 come from dependent base class. */
10737 /* The call to xref_tag_from_type does injection for friend
10738 classes. */
10740 friend_type =
10744 }
10746 /* friend class C<T>; */
10749 /* Otherwise it's
10751 friend class C;
10753 where C is already declared or
10755 friend class C<int>;
10757 We don't have to do anything in these cases. */
10760 /* Trick make_friend_class into realizing that the friend
10761 we're adding is a template, not an ordinary class. It's
10762 important that we use make_friend_class since it will
10763 perform some error-checking and output cross-reference
10764 information. */
10772 }
10773 else
10774 {
10775 /* Build new DECL_FRIENDLIST. */
10776 tree r;
10778 /* The file and line for this declaration, to
10779 assist in error message reporting. Since we
10780 called push_tinst_level above, we don't need to
10781 restore these. */
10785 {
10788 }
10793 {
10796 }
10797 }
10798 }
10799 }
10802 {
10803 /* Restore these before substituting into the lambda capture
10804 initializers. */
10807 }
10810 {
10813 {
10819 {
10820 /* Set function_depth to avoid garbage collection. */
10824 }
10826 /* We need to instantiate the capture list from the template
10827 after we've instantiated the closure members, but before we
10828 consider adding the conversion op. Also keep any captures
10829 that may have been added during instantiation of the op(). */
10831 tree tmpl_cap
10840 }
10841 else
10843 }
10845 /* Set the file and line number information to whatever is given for
10846 the class itself. This puts error messages involving generated
10847 implicit functions at a predictable point, and the same point
10848 that would be used for non-template classes. */
10855 /* We don't instantiate default arguments for member functions. 14.7.1:
10857 The implicit instantiation of a class template specialization causes
10858 the implicit instantiation of the declarations, but not of the
10859 definitions or default arguments, of the class member functions,
10860 member classes, static data members and member templates.... */
10862 /* Some typedefs referenced from within the template code need to be access
10863 checked at template instantiation time, i.e now. These types were
10864 added to the template at parsing time. Let's get those and perform
10865 the access checks then. */
10875 /* The vtable for a template class can be emitted in any translation
10876 unit in which the class is instantiated. When there is no key
10877 method, however, finish_struct_1 will already have added TYPE to
10878 the keyed_classes. */
10883 }
10885 /* Wrapper for instantiate_class_template_1. */
10887 tree
10889 {
10890 tree ret;
10895 }
10897 static tree
10899 {
10900 tree r;
10906 else
10907 {
10914 }
10916 }
10918 /* Given a function parameter pack TMPL_PARM and some function parameters
10919 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10920 and set *SPEC_P to point at the next point in the list. */
10922 tree
10924 {
10925 /* Collect all of the extra "packed" parameters into an
10926 argument pack. */
10927 tree parmvec;
10937 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10943 /* Build the argument packs. */
10948 }
10950 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10951 NONTYPE_ARGUMENT_PACK. */
10953 static tree
10955 {
10957 }
10959 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10960 pack expansion with no extra args, 2 if it has extra args, or 0
10961 if it is not a pack expansion. */
10963 static int
10965 {
10971 /* A decl pack is itself an expansion. */
10978 }
10981 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10983 static tree
10985 {
10992 }
10994 /* This is a subroutine of tsubst_pack_expansion.
10996 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10997 mechanism to store the (non complete list of) arguments of the
10998 substitution and return a non substituted pack expansion, in order
10999 to wait for when we have enough arguments to really perform the
11000 substitution. */
11002 static bool
11006 {
11007 /* If one pack has an expansion and another pack has a normal
11008 argument or if one pack has an empty argument and an another
11009 one hasn't then tsubst_pack_expansion cannot perform the
11010 substitution and need to fall back on the
11011 PACK_EXPANSION_EXTRA mechanism. */
11019 {
11022 parm_pack;
11024 {
11029 /* We can't substitute a pack expansion with extra args into
11030 our pattern. */
11034 else
11036 }
11040 }
11042 }
11044 /* [temp.variadic]/6 says that:
11046 The instantiation of a pack expansion [...]
11047 produces a list E1,E2, ..., En, where N is the number of elements
11048 in the pack expansion parameters.
11050 This subroutine of tsubst_pack_expansion produces one of these Ei.
11052 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11053 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11054 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11055 INDEX is the index 'i' of the element Ei to produce. ARGS,
11056 COMPLAIN, and IN_DECL are the same parameters as for the
11057 tsubst_pack_expansion function.
11059 The function returns the resulting Ei upon successful completion,
11060 or error_mark_node.
11062 Note that this function possibly modifies the ARGS parameter, so
11063 it's the responsibility of the caller to restore it. */
11065 static tree
11067 tree parm_packs,
11069 tree args /* This parm gets
11071 tsubst_flags_t complain,
11072 tree in_decl)
11073 {
11074 tree t;
11077 /* For each parameter pack, change the substitution of the parameter
11078 pack to the ith argument in its argument pack, then expand the
11079 pattern. */
11081 {
11086 ith_elem_is_expansion |=
11089 /* Select the Ith argument from the pack. */
11092 {
11094 {
11099 }
11100 else
11102 }
11103 else
11104 {
11109 {
11111 /* Update the corresponding argument. */
11113 }
11114 else
11115 /* Re-use the ARGUMENT_PACK_SELECT. */
11117 }
11119 }
11121 /* Substitute into the PATTERN with the (possibly altered)
11122 arguments. */
11124 /* Expanding a fixed parameter pack from
11125 coerce_template_parameter_pack. */
11130 {
11133 else
11136 }
11140 else
11143 /* If the Ith argument pack element is a pack expansion, then
11144 the Ith element resulting from the substituting is going to
11145 be a pack expansion as well. */
11150 }
11152 /* When the unexpanded parameter pack in a fold expression expands to an empty
11153 sequence, the value of the expression is as follows; the program is
11154 ill-formed if the operator is not listed in this table.
11156 && true
11157 || false
11158 , void() */
11160 tree
11162 {
11166 {
11175 }
11181 }
11183 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11184 form an expression that combines the two terms using the
11185 operator of T. */
11187 static tree
11189 {
11193 // Handle compound assignment operators.
11198 {
11208 complain);
11209 }
11210 }
11212 /* Substitute ARGS into the pack of a fold expression T. */
11216 {
11218 }
11220 /* Substitute ARGS into the pack of a fold expression T. */
11224 {
11226 }
11228 /* Expand a PACK of arguments into a grouped as left fold.
11229 Given a pack containing elements A0, A1, ..., An and an
11230 operator @, this builds the expression:
11232 ((A0 @ A1) @ A2) ... @ An
11234 Note that PACK must not be empty.
11236 The operator is defined by the original fold expression T. */
11238 static tree
11240 {
11243 {
11246 }
11248 }
11250 /* Substitute into a unary left fold expression. */
11252 static tree
11254 tree in_decl)
11255 {
11260 {
11264 }
11267 else
11269 }
11271 /* Substitute into a binary left fold expression.
11273 Do ths by building a single (non-empty) vector of argumnts and
11274 building the expression from those elements. */
11276 static tree
11278 tree in_decl)
11279 {
11288 {
11293 }
11301 }
11303 /* Expand a PACK of arguments into a grouped as right fold.
11304 Given a pack containing elementns A0, A1, ..., and an
11305 operator @, this builds the expression:
11307 A0@ ... (An-2 @ (An-1 @ An))
11309 Note that PACK must not be empty.
11311 The operator is defined by the original fold expression T. */
11313 tree
11315 {
11316 // Build the expression.
11320 {
11323 }
11325 }
11327 /* Substitute into a unary right fold expression. */
11329 static tree
11331 tree in_decl)
11332 {
11337 {
11341 }
11344 else
11346 }
11348 /* Substitute into a binary right fold expression.
11350 Do ths by building a single (non-empty) vector of arguments and
11351 building the expression from those elements. */
11353 static tree
11355 tree in_decl)
11356 {
11365 {
11370 }
11379 }
11382 /* Substitute ARGS into T, which is an pack expansion
11383 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11384 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11385 (if only a partial substitution could be performed) or
11386 ERROR_MARK_NODE if there was an error. */
11387 tree
11389 tree in_decl)
11390 {
11391 tree pattern;
11395 tree result;
11403 /* Add in any args remembered from an earlier partial instantiation. */
11408 /* Determine the argument packs that will instantiate the parameter
11409 packs used in the expansion expression. While we're at it,
11410 compute the number of arguments to be expanded and make sure it
11411 is consistent. */
11414 {
11421 {
11426 else
11429 }
11431 {
11432 /* ??? Support use in other patterns. */
11436 }
11438 {
11439 /* We know we have correct local_specializations if this
11440 expansion is at function scope, or if we're dealing with a
11441 local parameter in a requires expression; for the latter,
11442 tsubst_requires_expr set it up appropriately. */
11445 else
11446 /* We can't rely on local_specializations for a parameter
11447 name used later in a function declaration (such as in a
11448 late-specified return type). Even if it exists, it might
11449 have the wrong value for a recursive call. */
11453 {
11454 /* This parameter pack was used in an unevaluated context. Just
11455 make a dummy decl, since it's only used for its type. */
11458 /* Partial instantiation of the parm_pack, we can't build
11459 up an argument pack yet. */
11461 else
11463 }
11464 }
11467 else
11468 {
11474 }
11481 /* This can only happen if we forget to expand an argument
11482 pack somewhere else. Just return an error, silently. */
11483 {
11487 }
11490 {
11494 /* Don't bother trying to do a partial substitution with
11495 incomplete packs; we'll try again after deduction. */
11502 {
11507 pattern);
11508 else
11510 pattern);
11512 }
11514 /* Keep track of the parameter packs and their corresponding
11515 argument packs. */
11518 }
11519 else
11520 {
11521 /* We can't substitute for this parameter pack. We use a flag as
11522 well as the missing_level counter because function parameter
11523 packs don't have a level. */
11526 }
11527 }
11529 /* If the expansion is just T..., return the matching argument pack, unless
11530 we need to call convert_from_reference on all the elements. This is an
11531 important optimization; see c++/68422. */
11534 {
11536 /* Types need no adjustment, nor does sizeof..., and if we still have
11537 some pack expansion args we won't do anything yet. */
11542 /* Also optimize expression pack expansions if we can tell that the
11543 elements won't have reference type. */
11549 /* Otherwise use the normal path so we get convert_from_reference. */
11550 }
11552 /* We cannot expand this expansion expression, because we don't have
11553 all of the argument packs we need. */
11555 {
11556 /* We got some full packs, but we can't substitute them in until we
11557 have values for all the packs. So remember these until then. */
11562 }
11564 {
11565 /* There were no real arguments, we're just replacing a parameter
11566 pack with another version of itself. Substitute into the
11567 pattern and return a PACK_EXPANSION_*. The caller will need to
11568 deal with that. */
11572 else
11576 }
11581 {
11582 /* We're in a late-specified return type, so create our own local
11583 specializations map; the current map is either NULL or (in the
11584 case of recursive unification) might have bindings that we don't
11585 want to use or alter. */
11588 }
11590 /* For each argument in each argument pack, substitute into the
11591 pattern. */
11595 {
11597 i,
11599 in_decl);
11602 {
11605 }
11606 }
11608 /* Update ARGS to restore the substitution from parameter packs to
11609 their argument packs. */
11611 {
11617 else
11618 {
11626 /* Update the corresponding argument. */
11630 else
11632 }
11633 }
11636 {
11639 }
11641 /* If the dependent pack arguments were such that we end up with only a
11642 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11648 }
11650 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11651 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11652 parameter packs; all parms generated from a function parameter pack will
11653 have the same DECL_PARM_INDEX. */
11655 tree
11657 {
11659 tree patparm;
11662 {
11668 }
11669 else
11670 {
11675 }
11678 }
11680 /* Make an argument pack out of the TREE_VEC VEC. */
11682 static tree
11684 {
11685 tree pack;
11689 else
11690 {
11693 }
11696 }
11698 /* Return an exact copy of template args T that can be modified
11699 independently. */
11701 static tree
11703 {
11711 {
11716 }
11722 }
11724 /* Substitute ARGS into the vector or list of template arguments T. */
11726 static tree
11728 {
11740 {
11742 tree new_arg;
11747 {
11748 /* Substitute into an expansion expression. */
11752 /* Add to the expanded length adjustment the number of
11753 expanded arguments. We subtract one from this
11754 measurement, because the argument pack expression
11755 itself is already counted as 1 in
11756 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11757 the argument pack is empty. */
11759 }
11761 {
11762 /* Substitute into each of the arguments. */
11771 else
11776 }
11777 else
11786 }
11791 /* Make space for the expanded arguments coming from template
11792 argument packs. */
11794 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11795 arguments for a member template.
11796 In that case each TREE_VEC in ORIG_T represents a level of template
11797 arguments, and ORIG_T won't carry any non defaulted argument count.
11798 It will rather be the nested TREE_VECs that will carry one.
11799 In other words, ORIG_T carries a non defaulted argument count only
11800 if it doesn't contain any nested TREE_VEC. */
11802 {
11806 }
11808 {
11812 {
11815 /* Now expand the template argument pack "in place". */
11818 }
11819 else
11820 {
11822 out++;
11823 }
11824 }
11827 }
11829 /* Substitute ARGS into one level PARMS of template parameters. */
11831 static tree
11833 {
11840 {
11848 }
11851 }
11853 /* Return the result of substituting ARGS into the template parameters
11854 given by PARMS. If there are m levels of ARGS and m + n levels of
11855 PARMS, then the result will contain n levels of PARMS. For
11856 example, if PARMS is `template <class T> template <class U>
11857 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11858 result will be `template <int*, double, class V>'. */
11860 static tree
11862 {
11866 /* When substituting into a template, we must set
11867 PROCESSING_TEMPLATE_DECL as the template parameters may be
11868 dependent if they are based on one-another, and the dependency
11869 predicates are short-circuit outside of templates. */
11876 {
11883 }
11888 }
11890 /* Return the result of substituting ARGS into one template parameter
11891 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11892 parameter and which TREE_PURPOSE is the default argument of the
11893 template parameter. */
11895 static tree
11897 {
11918 }
11920 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11921 type T. If T is not an aggregate or enumeration type, it is
11922 handled as if by tsubst. IN_DECL is as for tsubst. If
11923 ENTERING_SCOPE is nonzero, T is the context for a template which
11924 we are presently tsubst'ing. Return the substituted value. */
11926 static tree
11928 tree args,
11929 tsubst_flags_t complain,
11930 tree in_decl,
11932 {
11937 {
11942 /* Fall through. */
11946 {
11947 tree argvec;
11948 tree context;
11949 tree r;
11953 /* In "sizeof(X<I>)" we need to evaluate "I". */
11959 /* First, determine the context for the type we are looking
11960 up. */
11963 {
11966 /* If context is a nested class inside a class template,
11967 it may still need to be instantiated (c++/33959). */
11969 }
11971 /* Then, figure out what arguments are appropriate for the
11972 type we are trying to find. For example, given:
11974 template <class T> struct S;
11975 template <class T, class U> void f(T, U) { S<U> su; }
11977 and supposing that we are instantiating f<int, double>,
11978 then our ARGS will be {int, double}, but, when looking up
11979 S we only want {double}. */
11984 else
11985 {
11989 }
11995 }
11996 else
11997 /* This is not a template type, so there's nothing to do. */
12002 }
12003 }
12005 /* Substitute into the default argument ARG (a default argument for
12006 FN), which has the indicated TYPE. */
12008 tree
12010 {
12015 /* This can happen in invalid code. */
12019 /* This default argument came from a template. Instantiate the
12020 default argument here, not in tsubst. In the case of
12021 something like:
12023 template <class T>
12024 struct S {
12025 static T t();
12026 void f(T = t());
12027 };
12029 we must be careful to do name lookup in the scope of S<T>,
12030 rather than in the current class. */
12032 /* The "this" pointer is not valid in a default argument. */
12034 {
12039 }
12042 /* The default argument expression may cause implicitly defined
12043 member functions to be synthesized, which will result in garbage
12044 collection. We must treat this situation as if we were within
12045 the body of function so as to avoid collecting live data on the
12046 stack. */
12054 /* Restore the "this" pointer. */
12056 {
12059 }
12066 /* Make sure the default argument is reasonable. */
12072 }
12074 /* Substitute into all the default arguments for FN. */
12076 static void
12078 {
12079 tree arg;
12080 tree tmpl_args;
12084 /* If this function is not yet instantiated, we certainly don't need
12085 its default arguments. */
12088 /* Don't do this again for clones. */
12093 arg;
12099 complain);
12100 }
12102 /* Substitute the ARGS into the T, which is a _DECL. Return the
12103 result of the substitution. Issue error and warning messages under
12104 control of COMPLAIN. */
12106 static tree
12108 {
12109 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12110 location_t saved_loc;
12115 /* Set the filename and linenumber to improve error-reporting. */
12120 {
12122 {
12123 /* We can get here when processing a member function template,
12124 member class template, or template template parameter. */
12126 tree spec;
12127 tree tmpl_args;
12128 tree full_args;
12131 {
12132 /* Template template parameter is treated here. */
12136 /* If we get a real template back, return it. This can happen in
12137 the context of most_specialized_partial_spec. */
12140 else
12141 /* The new TEMPLATE_DECL was built in
12142 reduce_template_parm_level. */
12145 }
12147 /* We might already have an instance of this template.
12148 The ARGS are for the surrounding class type, so the
12149 full args contain the tsubst'd args for the context,
12150 plus the innermost args from the template decl. */
12154 /* Because this is a template, the arguments will still be
12155 dependent, even after substitution. If
12156 PROCESSING_TEMPLATE_DECL is not set, the dependency
12157 predicates will short-circuit. */
12165 /* If this is a default template template argument,
12166 tsubst might not have changed anything. */
12173 {
12176 }
12178 /* Make a new template decl. It will be similar to the
12179 original, but will record the current template arguments.
12180 We also create a new function declaration, which is just
12181 like the old one, but points to this new template, rather
12182 than the old one. */
12187 // Build new template info linking to the original template decl.
12192 {
12193 tree new_type;
12201 /* For a partial specialization, we need to keep pointing to
12202 the primary template. */
12208 }
12209 else
12210 {
12211 tree new_decl;
12223 }
12229 /* The template parameters for this new template are all the
12230 template parameters for the old template, except the
12231 outermost level of parameters. */
12234 complain);
12240 /* Record this non-type partial instantiation. */
12244 }
12248 {
12251 /* Nobody should be tsubst'ing into non-template functions. */
12255 {
12256 /* If T is not dependent, just return it. */
12260 /* Calculate the most general template of which R is a
12261 specialization, and the complete set of arguments used to
12262 specialize R. */
12265 (DECL_TEMPLATE_RESULT
12271 /* Check to see if we already have this specialization. */
12274 {
12277 }
12279 /* We can see more levels of arguments than parameters if
12280 there was a specialization of a member template, like
12281 this:
12283 template <class T> struct S { template <class U> void f(); }
12284 template <> template <class U> void S<int>::f(U);
12286 Here, we'll be substituting into the specialization,
12287 because that's where we can find the code we actually
12288 want to generate, but we'll have enough arguments for
12289 the most general template.
12291 We also deal with the peculiar case:
12293 template <class T> struct S {
12294 template <class U> friend void f();
12295 };
12296 template <class U> void f() {}
12297 template S<int>;
12298 template void f<double>();
12300 Here, the ARGS for the instantiation of will be {int,
12301 double}. But, we only need as many ARGS as there are
12302 levels of template parameters in CODE_PATTERN. We are
12303 careful not to get fooled into reducing the ARGS in
12304 situations like:
12306 template <class T> struct S { template <class U> void f(U); }
12307 template <class T> template <> void S<T>::f(int) {}
12309 which we can spot because the pattern will be a
12310 specialization in this case. */
12317 }
12318 else
12319 {
12320 /* This special case arises when we have something like this:
12322 template <class T> struct S {
12323 friend void f<int>(int, double);
12324 };
12326 Here, the DECL_TI_TEMPLATE for the friend declaration
12327 will be an IDENTIFIER_NODE. We are being called from
12328 tsubst_friend_function, and we want only to create a
12329 new decl (R) with appropriate types so that we can call
12330 determine_specialization. */
12333 }
12347 /* If we hit excessive deduction depth, the type is bogus even if
12348 it isn't error_mark_node, so don't build a decl. */
12352 /* We do NOT check for matching decls pushed separately at this
12353 point, as they may not represent instantiations of this
12354 template, and in any case are considered separate under the
12355 discrete model. */
12359 /* Clear out the mangled name and RTL for the instantiation. */
12362 /* Leave DECL_INITIAL set on deleted instantiations. */
12367 /* OpenMP UDRs have the only argument a reference to the declared
12368 type. We want to diagnose if the declared type is a reference,
12369 which is invalid, but as references to references are usually
12370 quietly merged, diagnose it here. */
12372 {
12373 tree argtype
12378 "reference type %qT in "
12382 argtype);
12383 }
12386 /* Type-conversion operator. Reconstruct the name, in
12387 case it's the name of one of the template's parameters. */
12397 /* If this is an instantiation of a function with internal
12398 linkage, we already know what object file linkage will be
12399 assigned to the instantiation. */
12408 /* We'll re-clone as appropriate in instantiate_template. */
12411 /* If we aren't complaining now, return on error before we register
12412 the specialization so that we'll complain eventually. */
12418 /* When instantiating a constrained member, substitute
12419 into the constraints to create a new constraint. */
12422 {
12425 }
12427 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12428 this in the special friend case mentioned above where
12429 GEN_TMPL is NULL. */
12431 {
12436 tree new_r
12439 /* We instantiated this while substituting into
12440 the type earlier (template/friend54.C). */
12443 /* We're not supposed to instantiate default arguments
12444 until they are called, for a template. But, for a
12445 declaration like:
12447 template <class T> void f ()
12448 { extern void g(int i = T()); }
12450 we should do the substitution when the template is
12451 instantiated. We handle the member function case in
12452 instantiate_class_template since the default arguments
12453 might refer to other members of the class. */
12458 }
12459 else
12462 /* Copy the list of befriending classes. */
12466 {
12470 }
12473 {
12477 /* If this is an instantiation of a member template, clone it.
12478 If it isn't, that'll be handled by
12479 clone_constructors_and_destructors. */
12482 }
12493 /* Possibly limit visibility based on template args. */
12496 {
12500 }
12508 }
12512 {
12520 {
12521 /* If there is a local specialization that isn't a
12522 parameter pack, it means that we're doing a "simple"
12523 substitution from inside tsubst_pack_expansion. Just
12524 return the local specialization (which will be a single
12525 parm). */
12532 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12533 the parameters in this function parameter pack. */
12537 {
12540 /* Zero-length parameter packs are boring. Just substitute
12541 into the chain. */
12545 }
12546 else
12547 {
12548 /* All we did was update the type. Make a note of that. */
12551 }
12552 }
12554 /* Loop through all of the parameters we'll build. When T is
12555 a function parameter pack, LEN is the number of expanded
12556 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12559 {
12566 /* We're on the Ith parameter of the function parameter
12567 pack. */
12568 {
12569 /* Get the Ith type. */
12572 /* Rename the parameter to include the index. */
12575 }
12577 /* We're dealing with a normal parameter. */
12585 {
12588 else
12591 }
12601 /* Keep track of the first new parameter we
12602 generate. That's what will be returned to the
12603 caller. */
12607 /* Build a proper chain of parameters when substituting
12608 into a function parameter pack. */
12611 }
12613 /* If cp_unevaluated_operand is set, we're just looking for a
12614 single dummy parameter, so don't keep going. */
12619 /* FIRST_R contains the start of the chain we've built. */
12621 }
12625 {
12632 {
12633 /* This field is a lambda capture pack. Return a TREE_VEC of
12634 the expanded fields to instantiate_class_template_1 and
12635 store them in the specializations hash table as a
12636 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12640 {
12643 }
12644 else
12645 {
12646 /* All we did was update the type. Make a note of that. */
12649 }
12650 }
12653 {
12656 {
12660 }
12670 /* For bit-fields, DECL_INITIAL gives the number of bits. For
12671 non-bit-fields DECL_INITIAL is a non-static data member
12672 initializer, which gets deferred instantiation. */
12678 {
12679 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12680 NSDMI in perform_member_init. Still set DECL_INITIAL
12681 so that we know there is one. */
12686 }
12687 /* We don't have to set DECL_CONTEXT here; it is set by
12688 finish_member_declaration. */
12696 }
12699 {
12704 }
12705 }
12709 /* We reach here only for member using decls. We also need to check
12710 uses_template_parms because DECL_DEPENDENT_P is not set for a
12711 using-declaration that designates a member of the current
12712 instantiation (c++/53549). */
12715 {
12719 {
12724 {
12728 {
12731 }
12732 else
12733 {
12736 }
12738 }
12739 }
12740 else
12741 {
12747 else
12748 {
12751 }
12752 }
12753 }
12754 else
12755 {
12758 }
12763 {
12766 tree spec;
12768 tree ctx;
12777 {
12778 /* If this is the canonical decl, we don't have to
12779 mess with instantiations, and often we can't (for
12780 typename, template type parms and such). Note that
12781 TYPE_NAME is not correct for the above test if
12782 we've copied the type for a typedef. */
12788 }
12790 /* Check to see if we already have the specialization we
12791 need. */
12794 {
12795 /* T is a static data member or namespace-scope entity.
12796 We have to substitute into namespace-scope variables
12797 (not just variable templates) because of cases like:
12799 template <class T> void f() { extern T t; }
12801 where the entity referenced is not known until
12802 instantiation time. */
12806 {
12808 complain,
12810 /* If CTX is unchanged, then T is in fact the
12811 specialization we want. That situation occurs when
12812 referencing a static data member within in its own
12813 class. We can use pointer equality, rather than
12814 same_type_p, because DECL_CONTEXT is always
12815 canonical... */
12817 /* ... unless T is a member template; in which
12818 case our caller can be willing to create a
12819 specialization of that template represented
12820 by T. */
12824 }
12827 {
12832 argvec = (coerce_innermost_template_parms
12840 }
12841 }
12842 else
12843 {
12844 /* A local variable. */
12846 /* Subsequent calls to pushdecl will fill this in. */
12848 /* Unless this is a reference to a static variable from an
12849 enclosing function, in which case we need to fill it in now. */
12851 {
12855 }
12857 }
12858 /* If we already have the specialization we need, there is
12859 nothing more to do. */
12861 {
12864 }
12866 /* Create a new node for the specialization we need. */
12869 {
12872 else
12881 /* Mask off any template args past the variable's context so we
12882 don't replace the auto with an unrelated argument. */
12887 }
12889 {
12890 /* Even if the original location is out of scope, the
12891 newly substituted one is not. */
12898 {
12899 /* It may seem that this case cannot occur, since:
12901 typedef void f();
12902 void g() { f x; }
12904 declares a function, not a variable. However:
12906 typedef void f();
12907 template <typename T> void g() { T t; }
12908 template void g<f>();
12910 is an attempt to declare a variable with function
12911 type. */
12913 /* R is not yet sufficiently initialized, so we
12914 just use its name. */
12917 }
12919 /* Wait until cp_finish_decl to set this again, to handle
12920 circular dependency (template/instantiate6.C). */
12925 {
12930 {
12933 }
12935 }
12939 }
12945 /* Clear out the mangled name and RTL for the instantiation. */
12949 /* The initializer must not be expanded until it is required;
12950 see [temp.inst]. */
12954 {
12957 /* Possibly limit visibility based on template args. */
12960 {
12964 }
12966 }
12969 {
12970 /* A static data member declaration is always marked
12971 external when it is declared in-class, even if an
12972 initializer is present. We mimic the non-template
12973 processing here. */
12981 }
12982 else
12983 {
12988 }
12996 /* Preserve a typedef that names a type. */
12998 {
13002 /* An alias template specialization can be dependent
13003 even if its underlying type is not. */
13005 }
13008 }
13013 }
13014 #undef RETURN
13016 out:
13017 /* Restore the file and line information. */
13021 }
13023 /* Substitute into the ARG_TYPES of a function type.
13024 If END is a TREE_CHAIN, leave it and any following types
13025 un-substituted. */
13027 static tree
13029 tree args,
13030 tree end,
13031 tsubst_flags_t complain,
13032 tree in_decl)
13033 {
13034 tree remaining_arg_types;
13038 tree default_arg;
13049 {
13050 /* For a pack expansion, perform substitution on the
13051 entire expression. Later on, we'll handle the arguments
13052 one-by-one. */
13057 /* So that we'll spin through the parameters, one by one. */
13059 else
13060 {
13061 /* We only partially substituted into the parameter
13062 pack. Our type is TYPE_PACK_EXPANSION. */
13065 }
13066 }
13079 {
13081 {
13085 }
13087 }
13088 /* DR 657. */
13092 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13093 top-level qualifiers as required. */
13096 /* We do not substitute into default arguments here. The standard
13097 mandates that they be instantiated only when needed, which is
13098 done in build_over_call. */
13102 {
13103 /* We've instantiated a template before its default arguments
13104 have been parsed. This can happen for a nested template
13105 class, and is not an error unless we require the default
13106 argument in a call of this function. */
13107 remaining_arg_types =
13110 }
13111 else
13112 remaining_arg_types =
13114 }
13117 }
13119 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13120 *not* handle the exception-specification for FNTYPE, because the
13121 initial substitution of explicitly provided template parameters
13122 during argument deduction forbids substitution into the
13123 exception-specification:
13125 [temp.deduct]
13127 All references in the function type of the function template to the
13128 corresponding template parameters are replaced by the specified tem-
13129 plate argument values. If a substitution in a template parameter or
13130 in the function type of the function template results in an invalid
13131 type, type deduction fails. [Note: The equivalent substitution in
13132 exception specifications is done only when the function is instanti-
13133 ated, at which point a program is ill-formed if the substitution
13134 results in an invalid type.] */
13136 static tree
13138 tree args,
13139 tsubst_flags_t complain,
13140 tree in_decl)
13141 {
13142 tree return_type;
13144 tree fntype;
13146 /* The TYPE_CONTEXT is not used for function/method types. */
13149 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13150 failure. */
13154 {
13155 /* Substitute the argument types. */
13167 {
13168 /* DR 1207: 'this' is in scope in the trailing return type. */
13170 }
13172 /* Substitute the return type. */
13176 {
13179 }
13180 }
13181 else
13182 /* Substitute the return type. */
13187 /* DR 486 clarifies that creation of a function type with an
13188 invalid return type is a deduction failure. */
13191 {
13193 {
13196 else
13198 }
13200 }
13201 /* And DR 657. */
13206 {
13207 /* Substitute the argument types. */
13212 }
13214 /* Construct a new type node and return it. */
13216 {
13221 }
13222 else
13223 {
13225 /* Don't pick up extra function qualifiers from the basetype. */
13228 {
13229 /* [temp.deduct]
13231 Type deduction may fail for any of the following
13232 reasons:
13234 -- Attempting to create "pointer to member of T" when T
13235 is not a class type. */
13238 r);
13240 }
13245 }
13252 }
13254 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13255 ARGS into that specification, and return the substituted
13256 specification. If there is no specification, return NULL_TREE. */
13258 static tree
13260 tree args,
13261 tsubst_flags_t complain,
13262 tree in_decl,
13264 {
13265 tree specs;
13266 tree new_specs;
13271 {
13272 /* A noexcept-specifier. */
13277 {
13278 /* Defer instantiation of noexcept-specifiers to avoid
13279 excessive instantiations (c++/49107). */
13282 {
13283 /* We already partially instantiated this member template,
13284 so combine the new args with the old. */
13289 }
13290 else
13291 {
13294 }
13295 }
13296 else
13297 new_specs = tsubst_copy_and_build
13301 }
13303 {
13306 else
13308 {
13309 tree spec;
13314 {
13315 /* Expand the pack expansion type. */
13318 in_decl);
13324 else
13325 {
13326 /* We're substituting into a member template, so
13327 we got a TYPE_PACK_EXPANSION back. Add that
13328 expansion and move on. */
13332 expanded_specs,
13333 complain);
13336 }
13337 }
13340 {
13343 else
13348 complain);
13349 }
13352 }
13353 }
13355 }
13357 /* Take the tree structure T and replace template parameters used
13358 therein with the argument vector ARGS. IN_DECL is an associated
13359 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13360 Issue error and warning messages under control of COMPLAIN. Note
13361 that we must be relatively non-tolerant of extensions here, in
13362 order to preserve conformance; if we allow substitutions that
13363 should not be allowed, we may allow argument deductions that should
13364 not succeed, and therefore report ambiguous overload situations
13365 where there are none. In theory, we could allow the substitution,
13366 but indicate that it should have failed, and allow our caller to
13367 make sure that the right thing happens, but we don't try to do this
13368 yet.
13370 This function is used for dealing with types, decls and the like;
13371 for expressions, use tsubst_expr or tsubst_copy. */
13373 tree
13375 {
13398 else
13403 /* Reuse typedefs. We need to do this to handle dependent attributes,
13404 such as attribute aligned. */
13407 {
13411 {
13412 /* DECL represents an alias template and we want to
13413 instantiate it. */
13417 }
13421 {
13425 }
13430 else
13431 /* The typedef is from a non-template context. */
13435 {
13437 r = cp_build_qualified_type_real
13441 }
13442 else
13443 {
13444 /* We don't have an instantiation yet, so drop the typedef. */
13449 }
13450 }
13467 {
13493 {
13499 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13500 needed. */
13506 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13507 with TREE_SIDE_EFFECTS that indicates this is not an integral
13508 constant expression. */
13511 {
13514 }
13517 }
13523 {
13529 /* Early in template argument deduction substitution, we don't
13530 want to reduce the level of 'auto', or it will be confused
13531 with a normal template parm in subsequent deduction. */
13543 {
13547 {
13548 /* See through ARGUMENT_PACK_SELECT arguments. */
13550 /* If the selected argument is an expansion E, that most
13551 likely means we were called from
13552 gen_elem_of_pack_expansion_instantiation during the
13553 substituting of pack an argument pack (which Ith
13554 element is a pack expansion, where I is
13555 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13556 In this case, the Ith element resulting from this
13557 substituting is going to be a pack expansion, which
13558 pattern is the pattern of E. Let's return the
13559 pattern of E, and
13560 gen_elem_of_pack_expansion_instantiation will
13561 build the resulting pack expansion from it. */
13563 {
13564 /* Make sure we aren't throwing away arg info. */
13567 }
13568 }
13569 }
13574 {
13576 /* If ARG is an argument pack, we don't actually want to
13577 perform a substitution here, because substitutions
13578 for argument packs are only done
13579 element-by-element. We can get to this point when
13580 substituting the type of a non-type template
13581 parameter pack, when that type actually contains
13582 template parameter packs from an outer template, e.g.,
13584 template<typename... Types> struct A {
13585 template<Types... Values> struct B { };
13586 }; */
13590 {
13596 return cp_build_qualified_type_real
13598 }
13600 {
13601 /* We are processing a type constructed from a
13602 template template parameter. */
13613 /* Consider this code:
13615 template <template <class> class Template>
13616 struct Internal {
13617 template <class Arg> using Bind = Template<Arg>;
13618 };
13620 template <template <class> class Template, class Arg>
13621 using Instantiate = Template<Arg>; //#0
13623 template <template <class> class Template,
13624 class Argument>
13625 using Bind =
13626 Instantiate<Internal<Template>::template Bind,
13627 Argument>; //#1
13629 When #1 is parsed, the
13630 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13631 parameter `Template' in #0 matches the
13632 UNBOUND_CLASS_TEMPLATE representing the argument
13633 `Internal<Template>::template Bind'; We then want
13634 to assemble the type `Bind<Argument>' that can't
13635 be fully created right now, because
13636 `Internal<Template>' not being complete, the Bind
13637 template cannot be looked up in that context. So
13638 we need to "store" `Bind<Argument>' for later
13639 when the context of Bind becomes complete. Let's
13640 store that in a TYPENAME_TYPE. */
13644 argvec),
13645 typename_type,
13646 complain);
13648 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13649 are resolving nested-types in the signature of a
13650 member function templates. Otherwise ARG is a
13651 TEMPLATE_DECL and is the real template to be
13652 instantiated. */
13660 complain);
13661 return cp_build_qualified_type_real
13663 }
13666 else
13667 /* TEMPLATE_PARM_INDEX. */
13669 }
13672 /* This can happen during the attempted tsubst'ing in
13673 unify. This means that we don't yet have any information
13674 about the template parameter in question. */
13677 /* If we get here, we must have been looking at a parm for a
13678 more deeply nested template. Make a new version of this
13679 template parameter, but with a lower level. */
13681 {
13686 {
13688 r = cp_build_qualified_type_real
13692 }
13699 /* Break infinite recursion when substituting the constraints
13701 else
13702 {
13713 {
13714 /* Propagate constraints on placeholders. */
13719 {
13723 }
13724 }
13727 /* We have reduced the level of the template
13728 template parameter, but not the levels of its
13729 template parameters, so canonical_type_parameter
13730 will not be able to find the canonical template
13731 template parameter for this level. Thus, we
13732 require structural equality checking to compare
13733 TEMPLATE_TEMPLATE_PARMs. */
13737 else
13741 {
13743 /* We might need to substitute into the types of non-type
13744 template parameters. */
13756 }
13757 }
13761 /* OK, now substitute the type of the non-type parameter. We
13762 couldn't do it earlier because it might be an auto parameter,
13763 and we wouldn't need to if we had an argument. */
13770 }
13773 }
13776 {
13784 {
13788 }
13791 {
13795 }
13798 {
13802 }
13808 }
13811 /* We should never be tsubsting a binfo. */
13815 /* A vector of template arguments. */
13821 {
13825 /* [temp.deduct]
13827 Type deduction may fail for any of the following
13828 reasons:
13830 -- Attempting to create a pointer to reference type.
13831 -- Attempting to create a reference to a reference type or
13832 a reference to void.
13834 Core issue 106 says that creating a reference to a reference
13835 during instantiation is no longer a cause for failure. We
13836 only enforce this check in strict C++98 mode. */
13840 {
13843 /* We keep track of the last time we issued this error
13844 message to avoid spewing a ton of messages during a
13845 single bad template instantiation. */
13848 {
13853 else
13856 }
13859 }
13863 {
13865 {
13868 type);
13869 else
13871 type);
13872 }
13874 }
13876 {
13880 }
13882 /* In C++0x, during template argument substitution, when there is an
13883 attempt to create a reference to a reference type, reference
13884 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13886 "If a template-argument for a template-parameter T names a type
13887 that is a reference to a type A, an attempt to create the type
13888 'lvalue reference to cv T' creates the type 'lvalue reference to
13889 A,' while an attempt to create the type type rvalue reference to
13890 cv T' creates the type T"
13891 */
13892 r = cp_build_reference_type
13895 else
13900 /* Will this ever be needed for TYPE_..._TO values? */
13904 }
13906 {
13909 {
13910 /* [temp.deduct]
13912 Type deduction may fail for any of the following
13913 reasons:
13915 -- Attempting to create "pointer to member of T" when T
13916 is not a class type. */
13920 }
13922 {
13926 }
13928 {
13932 }
13935 {
13936 /* The type of the implicit object parameter gets its
13937 cv-qualifiers from the FUNCTION_TYPE. */
13938 tree memptr;
13939 tree method_type
13944 complain);
13945 }
13946 else
13949 complain);
13950 }
13953 {
13954 tree fntype;
13955 tree specs;
13960 /* Substitute the exception specification. */
13968 }
13970 {
13975 /* As an optimization, we avoid regenerating the array type if
13976 it will obviously be the same as T. */
13980 /* These checks should match the ones in create_array_type_for_decl.
13982 [temp.deduct]
13984 The deduction may fail for any of the following reasons:
13986 -- Attempting to create an array with an element type that
13987 is void, a function type, or a reference type, or [DR337]
13988 an abstract class type. */
13994 {
13998 }
14006 {
14009 }
14012 }
14015 {
14027 {
14031 }
14033 {
14034 /* Normally, make_typename_type does not require that the CTX
14035 have complete type in order to allow things like:
14037 template <class T> struct S { typename S<T>::X Y; };
14039 But, such constructs have already been resolved by this
14040 point, so here CTX really should have complete type, unless
14041 it's a partial instantiation. */
14044 {
14048 }
14049 }
14056 {
14059 }
14062 {
14064 {
14068 else
14070 }
14072 {
14076 else
14078 }
14079 }
14081 return cp_build_qualified_type_real
14083 }
14086 {
14098 }
14101 {
14102 tree type;
14118 complain);
14119 }
14122 {
14123 tree type;
14134 {
14136 {
14140 }
14143 }
14154 else
14155 {
14159 /* In a template ~id could be either a complement expression
14160 or an unqualified-id naming a destructor; if instantiating
14161 it produces an expression, it's not an id-expression or
14162 member access. */
14165 }
14170 }
14173 {
14177 }
14181 {
14182 tree r;
14186 else
14194 }
14209 /* We should use one of the expression tsubsts for these codes. */
14215 }
14216 }
14218 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14219 expression on the left-hand side of the "." or "->" operator. A
14220 baselink indicates a function from a base class. Both the
14221 BASELINK_ACCESS_BINFO and the base class referenced may indicate
14222 bases of the template class, rather than the instantiated class.
14223 In addition, lookups that were not ambiguous before may be
14224 ambiguous now. Therefore, we perform the lookup again. */
14226 static tree
14229 {
14242 {
14249 }
14257 {
14262 }
14264 /* If lookup found a single function, mark it as used at this point.
14265 (If it lookup found multiple functions the one selected later by
14266 overload resolution will be marked as used at that point.) */
14274 {
14275 /* Add back the template arguments, if present. */
14281 /* Update the conversion operator type. */
14283 }
14289 {
14291 qualifying_scope,
14292 object_type);
14294 /* We need to call adjust_result_of_qualified_name_lookup in case the
14295 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14296 so that we still get virtual function binding. */
14298 }
14301 }
14303 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14304 true if the qualified-id will be a postfix-expression in-and-of
14305 itself; false if more of the postfix-expression follows the
14306 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14307 of "&". */
14309 static tree
14313 {
14314 tree expr;
14315 tree scope;
14316 tree name;
14318 tree template_args;
14323 /* Figure out what name to look up. */
14326 {
14336 }
14337 else
14338 {
14341 }
14343 /* Substitute into the qualifying scope. When there are no ARGS, we
14344 are just trying to simplify a non-dependent expression. In that
14345 case the qualifying scope may be dependent, and, in any case,
14346 substituting will not help. */
14349 {
14352 }
14353 else
14357 {
14364 }
14367 {
14369 {
14370 /* A BIT_NOT_EXPR is used to represent a destructor. */
14372 {
14376 }
14377 else
14380 }
14381 else
14385 {
14387 {
14391 }
14393 }
14394 }
14397 {
14399 scope);
14400 /* Remember that there was a reference to this entity. */
14403 }
14406 {
14412 }
14415 {
14418 complain);
14419 else
14421 }
14427 {
14428 expr = (adjust_result_of_qualified_name_lookup
14430 expr = (finish_qualified_id_expr
14434 }
14436 /* Expressions do not generally have reference type. */
14438 /* However, if we're about to form a pointer-to-member, we just
14439 want the referenced member referenced. */
14447 }
14449 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14450 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14451 for tsubst. */
14453 static tree
14456 {
14463 {
14464 /* If we had an initializer but it
14465 instantiated to nothing,
14466 value-initialize the object. This will
14467 only occur when the initializer was a
14468 pack expansion where the parameter packs
14469 used in that expansion were of length
14470 zero. */
14472 complain);
14477 }
14480 }
14482 /* Like tsubst, but deals with expressions. This function just replaces
14483 template parms; to finish processing the resultant expression, use
14484 tsubst_copy_and_build or tsubst_expr. */
14486 static tree
14488 {
14490 tree r;
14498 {
14503 {
14504 /* We get here for a use of 'this' in an NSDMI as part of a
14505 constructor call or as part of an aggregate initialization. */
14507 && ((current_function_decl
14509 || (current_class_ref
14513 /* This can happen for a parameter name used later in a function
14514 declaration (such as in a late-specified return type). Just
14515 make a dummy decl, since it's only used for its type. */
14518 /* Give it the template pattern as its context; its true context
14519 hasn't been instantiated yet and this is good enough for
14520 mangling. */
14522 }
14531 {
14532 tree enum_type;
14533 tree v;
14537 /* There is no need to substitute into namespace-scope
14538 enumerators. */
14541 /* If ARGS is NULL, then T is known to be non-dependent. */
14545 /* Unfortunately, we cannot just call lookup_name here.
14546 Consider:
14548 template <int I> int f() {
14549 enum E { a = I };
14550 struct S { void g() { E e = a; } };
14551 };
14553 When we instantiate f<7>::S::g(), say, lookup_name is not
14554 clever enough to find f<7>::a. */
14555 enum_type
14565 /* We didn't find the name. That should never happen; if
14566 name-lookup found it during preliminary parsing, we
14567 should find it again here during instantiation. */
14569 }
14574 {
14575 /* Check for a local specialization set up by
14576 tsubst_pack_expansion. */
14578 {
14582 }
14584 /* When retrieving a capture pack from a generic lambda, remove the
14585 lambda call op's own template argument list from ARGS. Only the
14586 template arguments active for the closure type should be used to
14587 retrieve the pack specialization. */
14593 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14594 tsubst_decl put in the hash table. */
14596 }
14599 {
14600 tree ctx;
14605 {
14608 {
14612 }
14614 }
14615 }
14625 {
14628 {
14629 /* First try name lookup to find the instantiation. */
14632 {
14633 /* Make sure that the one we found is the one we want. */
14639 }
14643 else
14644 {
14645 /* This can happen for a variable used in a
14646 late-specified return type of a local lambda, or for a
14647 local static or constant. Building a new VAR_DECL
14648 should be OK in all those cases. */
14651 /* Avoid infinite recursion (79640). */
14654 {
14655 /* We can't call cp_finish_decl, so handle the
14656 initializer by hand. */
14671 }
14678 }
14679 /* Remember this for subsequent uses. */
14682 }
14683 }
14684 else
14694 /* An OVERLOAD will always be a non-dependent overload set; an
14695 overload set from function scope will just be represented with an
14696 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14698 /* We must have marked any lookups as persistent. */
14714 {
14715 /* Template template argument like the following example need
14716 special treatment:
14718 template <template <class> class TT> struct C {};
14719 template <class T> struct D {
14720 template <class U> struct E {};
14721 C<E> c; // #1
14722 };
14723 D<int> d; // #2
14725 We are processing the template argument `E' in #1 for
14726 the template instantiation #2. Originally, `E' is a
14727 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14728 have to substitute this with one having context `D<int>'. */
14732 {
14733 /* When rewriting a constructor into a deduction guide, a
14734 non-dependent name can become dependent, so memtmpl<args>
14735 becomes context::template memtmpl<args>. */
14739 }
14741 }
14742 else
14743 /* Ordinary template template argument. */
14754 {
14758 }
14763 {
14772 /* We only want to compute the number of arguments. */
14775 else
14782 {
14784 /* Set TREE_USED for the benefit of -Wunused. */
14788 }
14796 {
14801 else
14807 else
14810 }
14811 else
14813 }
14815 {
14823 }
14824 /* Fall through */
14840 {
14844 }
14847 {
14848 tree object;
14849 tree name;
14854 {
14858 }
14861 {
14871 }
14876 in_decl);
14877 else
14880 }
14918 {
14922 }
14925 {
14930 }
14933 {
14937 }
14940 {
14948 }
14954 {
14961 }
14964 {
14971 }
14974 {
14981 }
14984 {
14985 /* Substituted template arguments */
14994 }
14997 {
15017 }
15042 /* Fall through. */
15045 {
15048 }
15049 else
15053 /* This is handled by tsubst_copy_and_build. */
15057 {
15061 }
15064 /* We shouldn't have built any of these during initial template
15065 generation. Instead, they should be built during instantiation
15066 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15070 {
15080 }
15098 {
15099 /* Instantiate any typedefs in the type. */
15104 }
15107 /* These can sometimes show up in a partial instantiation, but never
15108 involve template parms. */
15124 /* We shouldn't get here, but keep going if !flag_checking. */
15128 }
15129 }
15131 /* Helper function for tsubst_omp_clauses, used for instantiation of
15132 OMP_CLAUSE_DECL of clauses. */
15134 static tree
15136 tree in_decl)
15137 {
15141 /* Handle an OpenMP array section represented as a TREE_LIST (or
15142 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15143 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15144 TREE_LIST. We can handle it exactly the same as an array section
15145 (purpose, value, and a chain), even though the nomenclature
15146 (low_bound, length, etc) is different. */
15148 {
15149 tree low_bound
15155 in_decl);
15164 }
15167 /* Undo convert_from_reference tsubst_expr could have called. */
15173 }
15175 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15177 static tree
15180 {
15185 {
15191 {
15194 {
15200 }
15201 /* FALLTHRU */
15216 in_decl);
15248 {
15251 {
15258 }
15259 else
15261 }
15264 in_decl);
15270 in_decl);
15278 in_decl);
15280 {
15283 }
15288 else
15291 in_decl,
15315 }
15318 {
15328 /* tsubst_expr on SCOPE_REF results in returning
15329 finish_non_static_data_member result. Undo that here. */
15333 {
15338 {
15342 CASE_CONVERT:
15351 /* FALLTHRU */
15355 }
15356 }
15362 {
15365 {
15368 }
15369 }
15373 }
15374 }
15378 {
15383 {
15386 }
15387 }
15389 }
15391 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15393 static tree
15395 tree in_decl)
15396 {
15397 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15417 {
15420 else
15421 {
15425 }
15426 }
15431 #undef RECUR
15432 }
15434 /* Used to temporarily communicate the list of #pragma omp parallel
15435 clauses to #pragma omp for instantiation if they are combined
15436 together. */
15440 /* Substitute one OMP_FOR iterator. */
15442 static void
15447 {
15448 #define RECUR(NODE) \
15449 tsubst_expr ((NODE), args, complain, in_decl, \
15450 integral_constant_expression_p)
15457 {
15460 }
15466 {
15467 /* We need to jump through some hoops to handle declarations in the
15468 init-statement, since we might need to handle auto deduction,
15469 but we need to keep control of initialization. */
15473 }
15474 else
15475 {
15477 {
15480 {
15484 {
15488 CASE_CONVERT:
15496 {
15499 }
15500 /* FALLTHRU */
15504 }
15505 }
15506 }
15507 else
15509 }
15520 {
15522 {
15523 /* Declare the variable, but don't let that initialize it. */
15528 }
15533 {
15538 }
15539 else
15546 }
15549 {
15550 /* Declare and initialize the variable. */
15553 }
15555 {
15559 {
15561 {
15567 {
15570 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15575 }
15578 {
15580 decl);
15582 }
15585 {
15587 decl);
15589 }
15590 else
15592 }
15595 }
15597 {
15602 {
15605 }
15606 }
15607 }
15610 {
15614 }
15615 else
15619 {
15630 {
15638 }
15639 else
15645 {
15651 }
15655 {
15663 }
15664 else
15670 }
15676 #undef RECUR
15677 }
15679 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15680 of OMP_TARGET's body. */
15682 static tree
15684 {
15687 {
15696 }
15698 }
15700 /* Helper function for tsubst_expr. For decomposition declaration
15701 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15702 also the corresponding decls representing the identifiers
15703 of the decomposition declaration. Return DECL if successful
15704 or error_mark_node otherwise, set *FIRST to the first decl
15705 in the list chained through DECL_CHAIN and *CNT to the number
15706 of such decls. */
15708 static tree
15712 {
15717 decl2
15722 {
15724 {
15727 }
15744 {
15747 }
15748 else
15750 }
15753 }
15755 /* Like tsubst_copy for expressions, etc. but also does semantic
15756 processing. */
15758 tree
15761 {
15762 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15763 #define RECUR(NODE) \
15764 tsubst_expr ((NODE), args, complain, in_decl, \
15765 integral_constant_expression_p)
15768 tree r;
15769 location_t loc;
15781 {
15783 {
15784 tree_stmt_iterator i;
15788 }
15803 else
15813 {
15815 tree init;
15821 {
15831 else
15833 }
15835 {
15836 /* Don't build up decls for a variadic capture proxy, we'll
15837 instantiate the elements directly as needed. */
15839 }
15840 else
15841 {
15845 {
15846 /* By marking the declaration as instantiated, we avoid
15847 trying to instantiate it. Since instantiate_decl can't
15848 handle local variables, and since we've already done
15849 all that needs to be done, that's the right thing to
15850 do. */
15855 /* Anonymous aggregates are a special case. */
15858 {
15861 {
15865 }
15867 }
15873 {
15878 }
15879 else
15880 {
15885 {
15886 /* For __PRETTY_FUNCTION__ we have to adjust the
15887 initializer. */
15891 }
15892 else
15896 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15902 {
15904 tree first;
15910 }
15911 }
15912 }
15913 }
15916 }
15931 {
15939 {
15941 tree first;
15946 }
15947 else
15952 }
15978 else
15979 {
15986 }
15992 {
16001 }
16009 else
16017 else
16038 {
16045 }
16049 {
16051 tree label;
16058 }
16064 /* Computed goto's must be tsubst'd into. On the other hand,
16065 non-computed gotos must not be; the identifier in question
16066 will have no binding. */
16068 else
16074 {
16090 }
16095 {
16100 }
16101 else
16102 {
16107 else
16114 else
16120 else
16122 }
16126 {
16130 {
16132 /* Prevent instantiate_decl from trying to instantiate
16133 this variable. We've already done all that needs to be
16134 done. */
16137 }
16142 }
16148 {
16149 /* Local classes are not independent templates; they are
16150 instantiated along with their containing function. And this
16151 way we don't have to deal with pushing out of one local class
16152 to instantiate a member of another local class. */
16153 /* Closures are handled by the LAMBDA_EXPR. */
16163 }
16167 {
16168 tree condition;
16171 condition =
16173 args,
16182 }
16188 in_decl);
16225 {
16240 in_decl);
16242 {
16249 }
16261 integral_constant_expression_p);
16272 else
16273 {
16281 }
16285 }
16290 /* FALLTHRU */
16297 in_decl);
16314 in_decl);
16325 {
16328 {
16329 /* For combined target teams, ensure the num_teams and
16330 thread_limit clause expressions are evaluated on the host,
16331 before entering the target construct. */
16332 tree c;
16338 {
16347 OMP_CLAUSE_FIRSTPRIVATE);
16351 }
16352 }
16353 }
16413 {
16418 {
16421 }
16427 }
16428 else
16429 {
16436 {
16439 }
16442 {
16447 {
16450 }
16456 }
16457 else
16458 {
16462 }
16465 }
16469 {
16475 {
16479 {
16484 }
16488 }
16489 else
16490 {
16495 }
16496 }
16500 {
16504 }
16524 /* If the first operand was a statement, we're done with it. */
16528 complain));
16540 integral_constant_expression_p));
16541 }
16544 out:
16547 #undef RECUR
16548 #undef RETURN
16549 }
16551 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16552 function. For description of the body see comment above
16553 cp_parser_omp_declare_reduction_exprs. */
16555 static void
16557 {
16563 tree_stmt_iterator tsi;
16574 {
16593 }
16595 {
16615 }
16616 }
16618 /* T is a postfix-expression that is not being used in a function
16619 call. Return the substituted version of T. */
16621 static tree
16623 tsubst_flags_t complain,
16624 tree in_decl)
16625 {
16629 else
16635 }
16637 /* Like tsubst but deals with expressions and performs semantic
16638 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16640 tree
16642 tree args,
16643 tsubst_flags_t complain,
16644 tree in_decl,
16647 {
16648 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
16649 #define RECUR(NODE) \
16650 tsubst_copy_and_build (NODE, args, complain, in_decl, \
16652 integral_constant_expression_p)
16655 location_t loc;
16664 /* N3276 decltype magic only applies to calls at the top level or on the
16665 right side of a comma. */
16670 {
16673 /* Fall through. */
16675 {
16676 tree decl;
16677 cp_id_kind idk;
16682 {
16685 }
16687 /* Look up the name. */
16690 /* By convention, expressions use ERROR_MARK_NODE to indicate
16691 failure, not NULL_TREE. */
16697 integral_constant_expression_p,
16705 input_location);
16709 {
16713 }
16715 }
16718 {
16719 tree object;
16729 {
16734 }
16740 {
16743 }
16744 else
16751 else
16753 }
16756 {
16760 {
16761 /* A type conversion to reference type will be enclosed in
16762 such an indirect ref, but the substitution of the cast
16763 will have also added such an indirect ref. */
16766 }
16767 else
16775 }
16778 {
16782 }
16785 {
16792 flags));
16793 }
16796 {
16800 }
16807 {
16808 tree type;
16814 {
16819 }
16825 {
16843 }
16846 }
16880 else
16882 in_decl);
16917 {
16924 tree r = build_x_binary_op
16926 op0,
16928 ? ERROR_MARK
16930 op1,
16932 ? ERROR_MARK
16940 }
16943 {
16947 }
16960 {
16969 }
16974 /* Fall through */
16977 {
16978 tree r;
16984 {
16985 /* When there are no ARGS, we are trying to evaluate a
16986 non-dependent expression from the parser. Trying to do
16987 the substitutions may not work. */
16990 }
16991 else
16992 {
16997 else
17000 /*integral_constant_expression_p=*/
17004 }
17008 else
17012 {
17014 {
17016 {
17020 }
17021 else
17025 }
17027 }
17029 }
17032 {
17042 }
17058 {
17062 tree r = build_x_modify_expr
17065 /* TREE_NO_WARNING must be set if either the expression was
17066 parenthesized or it uses an operator such as >>= rather
17067 than plain assignment. In the former case, it was already
17068 set and must be copied. In the latter case,
17069 build_x_modify_expr sets it and it must not be reset
17070 here. */
17075 }
17080 /* Remember that there was a reference to this entity. */
17087 {
17092 tree ret;
17096 else
17097 {
17101 }
17103 /* If there was an initializer in the original tree, but it
17104 instantiated to an empty list, then we should pass a
17105 non-NULL empty vector to tell build_new that it was an
17106 empty initializer() rather than no initializer. This can
17107 only happen when the initializer is a pack expansion whose
17108 parameter packs are of length zero. */
17111 else
17112 {
17116 else
17117 {
17120 }
17121 }
17127 complain);
17135 }
17138 {
17144 complain));
17145 }
17148 {
17152 integral_constant_expression_p);
17154 op0,
17157 }
17160 {
17161 tree function;
17166 tree ret;
17169 /* Internal function with no arguments. */
17173 /* When we parsed the expression, we determined whether or
17174 not Koenig lookup should be performed. */
17177 {
17180 }
17182 {
17187 }
17189 {
17190 /* Do nothing; calling tsubst_copy_and_build on an identifier
17191 would incorrectly perform unqualified lookup again.
17193 Note that we can also have an IDENTIFIER_NODE if the earlier
17194 unqualified lookup found a member function; in that case
17195 koenig_p will be false and we do want to do the lookup
17196 again to find the instantiated member function.
17198 FIXME but doing that causes c++/15272, so we need to stop
17199 using IDENTIFIER_NODE in that situation. */
17201 }
17202 else
17203 {
17205 {
17211 }
17212 else
17217 /* Avoid error about taking the address of a constructor. */
17221 in_decl,
17223 integral_constant_expression_p);
17227 }
17232 {
17237 else
17238 {
17239 /* Expand the pack expansion and push each entry onto
17240 CALL_ARGS. */
17243 {
17248 {
17253 }
17254 }
17255 else
17256 {
17257 /* A partial substitution. Add one entry. */
17259 }
17260 }
17261 }
17263 /* We do not perform argument-dependent lookup if normal
17264 lookup finds a non-function, in accordance with the
17265 expected resolution of DR 218. */
17268 /* If lookup found a member function, the Koenig lookup is
17269 not appropriate, even if an unqualified-name was used
17270 to denote the function. */
17273 /* Only do this when substitution turns a dependent call
17274 into a non-dependent call. */
17282 {
17284 {
17285 /* For backwards compatibility and good diagnostics, try
17286 the unqualified lookup again if we aren't in SFINAE
17287 context. */
17288 tree unq = (tsubst_copy_and_build
17290 integral_constant_expression_p));
17292 {
17295 }
17298 {
17299 /* In a lambda fn, we have to be careful to not
17300 introduce new this captures. Legacy code can't
17301 be using lambdas anyway, so it's ok to be
17302 stricter. */
17307 "and no declarations were found by "
17308 "argument-dependent lookup at the point "
17315 else
17319 {
17330 {
17332 input_location);
17334 "declarations in dependent base %qT are "
17340 else
17344 }
17345 else
17347 "%qD declared here, later in the "
17350 {
17353 }
17354 }
17357 }
17358 }
17360 {
17365 }
17366 }
17368 /* Remember that there was a reference to this entity. */
17372 {
17375 }
17377 /* Put back tf_decltype for the actual call. */
17382 {
17386 {
17388 "wrong number of arguments to "
17391 }
17392 else
17394 input_location),
17399 /* Unsupported internal function with arguments. */
17401 }
17404 complain);
17406 {
17421 complain);
17422 else
17423 ret = (build_new_method_call
17428 complain));
17429 }
17430 else
17433 koenig_p,
17434 complain);
17439 {
17445 {
17451 {
17453 /* The thunk location is not interesting. */
17455 }
17456 }
17457 }
17460 }
17463 {
17469 {
17471 {
17476 }
17477 else
17478 {
17483 }
17485 }
17486 else
17487 {
17490 }
17494 }
17497 {
17502 input_location));
17503 }
17506 {
17514 {
17515 /* We have pack expansions, so expand those and
17516 create a new list out of it. */
17519 tree chain;
17522 /* Expand the argument expressions. */
17530 /* Build the rest of the list. */
17535 /* Determine the number of arguments. */
17537 {
17540 }
17543 else
17544 {
17545 /* Since we only performed a partial substitution into
17546 the argument pack, we only RETURN (a single list
17547 node. */
17554 }
17556 /* Convert the argument vectors into a TREE_LIST */
17559 {
17560 /* Grab the Ith values. */
17561 i--;
17564 value
17568 /* Build the list (backwards). */
17570 }
17573 }
17589 }
17592 {
17593 tree object;
17594 tree object_type;
17595 tree member;
17596 tree r;
17600 /* Remember that there was a reference to this entity. */
17611 else
17617 {
17622 }
17626 {
17628 {
17633 {
17636 }
17638 {
17643 }
17644 }
17645 }
17648 {
17649 /* Lookup the template functions now that we know what the
17650 scope is. */
17658 {
17661 args);
17662 member = (adjust_result_of_qualified_name_lookup
17664 object_type));
17665 }
17666 else
17667 {
17669 input_location);
17671 }
17672 }
17676 {
17678 {
17682 else
17685 }
17687 }
17691 complain);
17695 }
17702 {
17710 tree r;
17715 /* digest_init will do the wrong thing if we let it. */
17719 /* We do not want to process the index of aggregate
17720 initializers as they are identifier nodes which will be
17721 looked up by digest_init. */
17727 {
17729 /* An identifier index is looked up in the type
17730 being initialized, not the current scope. */
17735 {
17736 /* Substitute into the pack expansion. */
17738 in_decl);
17742 ;
17744 /* Just move the argument into place. */
17746 else
17747 {
17748 /* Update the length of the final CONSTRUCTOR
17749 arguments vector, and note that we will need to
17750 copy.*/
17753 }
17754 }
17755 else
17757 }
17760 {
17765 {
17767 {
17772 }
17773 else
17775 }
17776 }
17782 {
17787 }
17791 }
17794 {
17797 {
17800 }
17801 else
17802 {
17805 }
17806 }
17812 {
17813 /* We don't build decls for an instantiation of a
17814 variadic capture proxy, we instantiate the elements
17815 when needed. */
17818 }
17819 /* Fall through */
17822 {
17824 /* ??? We're doing a subset of finish_id_expression here. */
17826 && !processing_template_decl
17827 && !cp_unevaluated_operand
17830 {
17832 /* Replace an evaluated use of the thread_local variable with
17833 a call to its wrapper. */
17835 }
17837 {
17841 }
17844 /* If the original type was a reference, we'll be wrapped in
17845 the appropriate INDIRECT_REF. */
17848 }
17851 {
17855 }
17858 {
17859 tree object_ptr
17866 }
17873 {
17884 }
17887 {
17893 integral_constant_expression_p);
17897 /* If the resulting list of expression statement is empty,
17898 fold it further into void_node. */
17903 }
17906 {
17924 /* For a function or variable scope, we want to use tsubst so that we
17925 don't complain about referring to an auto before deduction. */
17928 {
17929 /* Look up the parameter we want directly, as tsubst_copy
17930 doesn't do what we need. */
17936 /* FIXME Work around the parm not having DECL_CONTEXT set. */
17939 }
17941 /* For a field, use tsubst_copy so that we look up the existing field
17942 rather than build a new one. */
17944 else
17951 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
17953 /* Now that we know visibility, instantiate the type so we have a
17954 declaration of the op() for later calls to lambda_function. */
17965 }
17968 /* We can get here for a constant initializer of non-dependent type.
17969 FIXME stop folding in cp_parser_initializer_clause. */
17970 {
17972 complain);
17974 }
17978 integral_constant_expression_p));
17984 {
17989 complain));
17990 }
17996 /* Handle Objective-C++ constructs, if appropriate. */
17997 {
17998 tree subst
18003 }
18005 }
18007 #undef RECUR
18008 #undef RETURN
18009 out:
18012 }
18014 /* Verify that the instantiated ARGS are valid. For type arguments,
18015 make sure that the type's linkage is ok. For non-type arguments,
18016 make sure they are constants if they are integral or enumerations.
18017 Emit an error under control of COMPLAIN, and return TRUE on error. */
18019 static bool
18021 {
18025 {
18035 }
18037 {
18038 /* [basic.link]: A name with no linkage (notably, the name
18039 of a class or enumeration declared in a local scope)
18040 shall not be used to declare an entity with linkage.
18041 This implies that names with no linkage cannot be used as
18042 template arguments
18044 DR 757 relaxes this restriction for C++0x. */
18049 {
18050 /* DR 488 makes use of a type with no linkage cause
18051 type deduction to fail. */
18053 {
18056 else
18059 }
18061 }
18062 /* In order to avoid all sorts of complications, we do not
18063 allow variably-modified types as template arguments. */
18065 {
18069 }
18070 }
18071 /* Class template and alias template arguments should be OK. */
18073 ;
18074 /* A non-type argument of integral or enumerated type must be a
18075 constant. */
18080 {
18084 }
18086 }
18088 static bool
18090 {
18095 {
18098 }
18102 }
18104 /* We're out of SFINAE context now, so generate diagnostics for the access
18105 errors we saw earlier when instantiating D from TMPL and ARGS. */
18107 static void
18109 {
18121 }
18123 /* Instantiate the indicated variable, function, or alias template TMPL with
18124 the template arguments in TARG_PTR. */
18126 static tree
18128 {
18130 tree fndecl;
18131 tree gen_tmpl;
18132 tree spec;
18140 /* If this function is a clone, handle it specially. */
18142 {
18143 tree spec;
18144 tree clone;
18146 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18147 DECL_CLONED_FUNCTION. */
18153 /* Look for the clone. */
18157 /* We should always have found the clone by now. */
18160 }
18165 /* Check to see if we already have this specialization. */
18169 /* targ_ptr only has the innermost template args, so add the outer ones
18170 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18171 the case of a non-dependent call within a template definition). */
18172 targ_ptr = (add_outermost_template_args
18174 targ_ptr));
18176 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18177 but it doesn't seem to be on the hot path. */
18186 {
18188 {
18192 }
18194 }
18197 complain))
18200 /* We are building a FUNCTION_DECL, during which the access of its
18201 parameters and return types have to be checked. However this
18202 FUNCTION_DECL which is the desired context for access checking
18203 is not built yet. We solve this chicken-and-egg problem by
18204 deferring all checks until we have the FUNCTION_DECL. */
18207 /* Instantiation of the function happens in the context of the function
18208 template, not the context of the overload resolution we're doing. */
18210 /* If there are dependent arguments, e.g. because we're doing partial
18211 ordering, make sure processing_template_decl stays set. */
18215 {
18219 }
18225 {
18226 /* We need to determine if we're using a partial or explicit
18227 specialization now, because the type of the variable could be
18228 different. */
18234 {
18239 }
18240 }
18242 /* Substitute template parameters to obtain the specialization. */
18250 {
18253 }
18255 /* The DECL_TI_TEMPLATE should always be the immediate parent
18256 template, not the most general template. */
18260 /* Now we know the specialization, compute access previously
18261 deferred. Do no access control for inheriting constructors,
18262 as we already checked access for the inherited constructor. */
18265 {
18270 }
18273 /* If we've just instantiated the main entry point for a function,
18274 instantiate all the alternate entry points as well. We do this
18275 by cloning the instantiation of the main entry point, not by
18276 instantiating the template clones. */
18281 {
18283 {
18284 /* Remember to reinstantiate when we're out of SFINAE so the user
18285 can see the errors. */
18287 }
18289 }
18291 }
18293 /* Wrapper for instantiate_template_1. */
18295 tree
18297 {
18298 tree ret;
18303 }
18305 /* Instantiate the alias template TMPL with ARGS. Also push a template
18306 instantiation level, which instantiate_template doesn't do because
18307 functions and variables have sufficient context established by the
18308 callers. */
18310 static tree
18312 {
18319 {
18322 }
18324 args =
18332 /* We can't free this if a pending_template entry or last_error_tinst_level
18333 is pointing at it. */
18339 }
18341 /* PARM is a template parameter pack for FN. Returns true iff
18342 PARM is used in a deducible way in the argument list of FN. */
18344 static bool
18346 {
18349 {
18351 tree packs;
18357 {
18358 /* The template parameter pack is used in a function parameter
18359 pack. If this is the end of the parameter list, the
18360 template parameter pack is deducible. */
18363 else
18364 /* Otherwise, not. Well, it could be deduced from
18365 a non-pack parameter, but doing so would end up with
18366 a deduction mismatch, so don't bother. */
18368 }
18369 }
18370 /* The template parameter pack isn't used in any function parameter
18371 packs, but it might be used deeper, e.g. tuple<Args...>. */
18373 }
18375 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18376 NARGS elements of the arguments that are being used when calling
18377 it. TARGS is a vector into which the deduced template arguments
18378 are placed.
18380 Returns either a FUNCTION_DECL for the matching specialization of FN or
18381 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18382 true, diagnostics will be printed to explain why it failed.
18384 If FN is a conversion operator, or we are trying to produce a specific
18385 specialization, RETURN_TYPE is the return type desired.
18387 The EXPLICIT_TARGS are explicit template arguments provided via a
18388 template-id.
18390 The parameter STRICT is one of:
18392 DEDUCE_CALL:
18393 We are deducing arguments for a function call, as in
18394 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18395 deducing arguments for a call to the result of a conversion
18396 function template, as in [over.call.object].
18398 DEDUCE_CONV:
18399 We are deducing arguments for a conversion function, as in
18400 [temp.deduct.conv].
18402 DEDUCE_EXACT:
18403 We are deducing arguments when doing an explicit instantiation
18404 as in [temp.explicit], when determining an explicit specialization
18405 as in [temp.expl.spec], or when taking the address of a function
18406 template, as in [temp.deduct.funcaddr]. */
18408 tree
18410 tree explicit_targs,
18411 tree targs,
18414 tree return_type,
18415 unification_kind_t strict,
18419 {
18420 tree parms;
18421 tree fntype;
18434 tree tinst;
18440 full_targs = (add_outermost_template_args
18442 targs));
18447 /* In C++0x, it's possible to have a function template whose type depends
18448 on itself recursively. This is most obvious with decltype, but can also
18449 occur with enumeration scope (c++/48969). So we need to catch infinite
18450 recursion and reject the substitution at deduction time; this function
18451 will return error_mark_node for any repeated substitution.
18453 This also catches excessive recursion such as when f<N> depends on
18454 f<N-1> across all integers, and returns error_mark_node for all the
18455 substitutions back up to the initial one.
18457 This is, of course, not reentrant. */
18467 {
18468 /* [temp.deduct]
18470 The specified template arguments must match the template
18471 parameters in kind (i.e., type, nontype, template), and there
18472 must not be more arguments than there are parameters;
18473 otherwise type deduction fails.
18475 Nontype arguments must match the types of the corresponding
18476 nontype template parameters, or must be convertible to the
18477 types of the corresponding nontype parameters as specified in
18478 _temp.arg.nontype_, otherwise type deduction fails.
18480 All references in the function type of the function template
18481 to the corresponding template parameters are replaced by the
18482 specified template argument values. If a substitution in a
18483 template parameter or in the function type of the function
18484 template results in an invalid type, type deduction fails. */
18495 explicit_targs);
18497 /* Adjust any explicit template arguments before entering the
18498 substitution context. */
18499 explicit_targs
18501 complain,
18507 /* Substitute the explicit args into the function type. This is
18508 necessary so that, for instance, explicitly declared function
18509 arguments can match null pointed constants. If we were given
18510 an incomplete set of explicit args, we must not do semantic
18511 processing during substitution as we could create partial
18512 instantiations. */
18514 {
18519 /* Dig out the actual parm. */
18522 {
18525 }
18527 {
18530 }
18533 /* No explicit argument for this template parameter. */
18537 {
18538 /* Mark the argument pack as "incomplete". We could
18539 still deduce more arguments during unification.
18540 We remove this mark in type_unification_real. */
18542 {
18546 }
18548 /* We have some incomplete argument packs. */
18550 }
18551 }
18555 {
18558 }
18561 /* Ignore any access checks; we'll see them again in
18562 instantiate_template and they might have the wrong
18563 access path at this point. */
18575 /* Place the explicitly specified arguments in TARGS. */
18579 }
18581 /* Never do unification on the 'this' parameter. */
18585 {
18586 /* We're deducing for a call to the result of a template conversion
18587 function. The parms we really want are in return_type. */
18591 }
18593 {
18602 }
18604 /* We allow incomplete unification without an error message here
18605 because the standard doesn't seem to explicitly prohibit it. Our
18606 callers must be ready to deal with unification failures in any
18607 event. */
18610 /* If we aren't explaining yet, push tinst context so we can see where
18611 any errors (e.g. from class instantiations triggered by instantiation
18612 of default template arguments) come from. If we are explaining, this
18613 context is redundant. */
18615 {
18618 }
18620 /* type_unification_real will pass back any access checks from default
18621 template argument substitution. */
18633 /* Now that we have bindings for all of the template arguments,
18634 ensure that the arguments deduced for the template template
18635 parameters have compatible template parameter lists. We cannot
18636 check this property before we have deduced all template
18637 arguments, because the template parameter types of a template
18638 template parameter might depend on prior template parameters
18639 deduced after the template template parameter. The following
18640 ill-formed example illustrates this issue:
18642 template<typename T, template<T> class C> void f(C<5>, T);
18644 template<int N> struct X {};
18646 void g() {
18647 f(X<5>(), 5l); // error: template argument deduction fails
18648 }
18650 The template parameter list of 'C' depends on the template type
18651 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18652 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18653 time that we deduce 'C'. */
18656 {
18659 }
18661 /* All is well so far. Now, check:
18663 [temp.deduct]
18665 When all template arguments have been deduced, all uses of
18666 template parameters in nondeduced contexts are replaced with
18667 the corresponding deduced argument values. If the
18668 substitution results in an invalid type, as described above,
18669 type deduction fails. */
18672 {
18675 }
18677 /* Also collect access checks from the instantiation. */
18690 /* Now perform any access checks encountered during substitution. */
18697 /* If we're looking for an exact match, check that what we got
18698 is indeed an exact match. It might not be if some template
18699 parameters are used in non-deduced contexts. But don't check
18700 for an exact match if we have dependent template arguments;
18701 in that case we're doing partial ordering, and we already know
18702 that we have two candidates that will provide the actual type. */
18704 {
18708 tree sarg
18714 {
18718 }
18719 }
18721 /* After doing deduction with the inherited constructor, actually return an
18722 instantiation of the inheriting constructor. */
18728 fail:
18731 {
18733 /* Reset once we're all the way out. */
18735 }
18737 /* We can't free this if a pending_template entry or last_error_tinst_level
18738 is pointing at it. */
18744 }
18746 /* Adjust types before performing type deduction, as described in
18747 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
18748 sections are symmetric. PARM is the type of a function parameter
18749 or the return type of the conversion function. ARG is the type of
18750 the argument passed to the call, or the type of the value
18751 initialized with the result of the conversion function.
18752 ARG_EXPR is the original argument expression, which may be null. */
18754 static int
18758 tree arg_expr)
18759 {
18763 {
18768 /* Swap PARM and ARG throughout the remainder of this
18769 function; the handling is precisely symmetric since PARM
18770 will initialize ARG rather than vice versa. */
18775 /* Core issue #873: Do the DR606 thing (see below) for these cases,
18776 too, but here handle it by stripping the reference from PARM
18777 rather than by adding it to ARG. */
18785 /* Nothing else to do in this case. */
18790 }
18793 {
18794 /* [temp.deduct.call]
18796 If P is not a reference type:
18798 --If A is an array type, the pointer type produced by the
18799 array-to-pointer standard conversion (_conv.array_) is
18800 used in place of A for type deduction; otherwise,
18802 --If A is a function type, the pointer type produced by
18803 the function-to-pointer standard conversion
18804 (_conv.func_) is used in place of A for type deduction;
18805 otherwise,
18807 --If A is a cv-qualified type, the top level
18808 cv-qualifiers of A's type are ignored for type
18809 deduction. */
18814 else
18816 }
18818 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
18819 reference to a cv-unqualified template parameter that does not represent a
18820 template parameter of a class template (during class template argument
18821 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
18822 an lvalue, the type "lvalue reference to A" is used in place of A for type
18823 deduction. */
18830 /* try_one_overload doesn't provide an arg_expr, but
18831 functions are always lvalues. */
18835 /* [temp.deduct.call]
18837 If P is a cv-qualified type, the top level cv-qualifiers
18838 of P's type are ignored for type deduction. If P is a
18839 reference type, the type referred to by P is used for
18840 type deduction. */
18843 {
18846 }
18848 /* DR 322. For conversion deduction, remove a reference type on parm
18849 too (which has been swapped into ARG). */
18854 }
18856 /* Subroutine of unify_one_argument. PARM is a function parameter of a
18857 template which does contain any deducible template parameters; check if
18858 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
18859 unify_one_argument. */
18861 static int
18864 {
18865 tree type;
18869 else
18876 {
18880 }
18882 {
18887 }
18891 else
18893 }
18897 /* Returns true iff the expression EXPR is one from which a template
18898 argument can be deduced. In other words, if it's an undecorated
18899 use of a template non-type parameter. */
18901 static bool
18903 {
18904 /* Strip implicit conversions. */
18908 }
18910 /* Returns true iff the array domain DOMAIN uses a template parameter in a
18911 deducible way; that is, if it has a max value of <PARM> - 1. */
18913 static bool
18915 {
18924 }
18926 /* Returns true iff the template arguments ARGS use a template parameter
18927 in a deducible way. */
18929 static bool
18931 {
18933 {
18938 else
18939 {
18946 else
18948 }
18951 }
18953 }
18955 /* Returns true iff TYPE contains any deducible references to template
18956 parameters, as per 14.8.2.5. */
18958 static bool
18960 {
18964 /* T
18965 cv-list T
18966 TT<T>
18967 TT<i>
18968 TT<> */
18973 /* T*
18974 T&
18975 T&& */
18979 /* T[integer-constant ]
18980 type [i] */
18985 /* T type ::*
18986 type T::*
18987 T T::*
18988 T (type ::*)()
18989 type (T::*)()
18990 type (type ::*)(T)
18991 type (T::*)(T)
18992 T (type ::*)(T)
18993 T (T::*)()
18994 T (T::*)(T) */
18997 || (uses_deducible_template_parms
19000 /* template-name <T> (where template-name refers to a class template)
19001 template-name <i> (where template-name refers to a class template) */
19008 /* type (T)
19009 T()
19010 T(T) */
19013 {
19022 }
19025 }
19027 /* Subroutine of type_unification_real and unify_pack_expansion to
19028 handle unification of a single P/A pair. Parameters are as
19029 for those functions. */
19031 static int
19035 {
19042 /* We can't deduce anything from this, but we might get all the
19043 template args from other function args. */
19046 /* Implicit conversions (Clause 4) will be performed on a function
19047 argument to convert it to the type of the corresponding function
19048 parameter if the parameter type contains no template-parameters that
19049 participate in template argument deduction. */
19052 /* For function parameters with no deducible template parameters,
19053 just return. We'll check non-dependent conversions later. */
19057 {
19059 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19060 | UNIFY_ALLOW_MORE_CV_QUAL
19074 }
19076 /* We only do these transformations if this is the top-level
19077 parameter_type_list in a call or declaration matching; in other
19078 situations (nested function declarators, template argument lists) we
19079 won't be comparing a type to an expression, and we don't do any type
19080 adjustments. */
19082 {
19084 {
19087 {
19088 /* [temp.deduct.type] A template-argument can be
19089 deduced from a pointer to function or pointer
19090 to member function argument if the set of
19091 overloaded functions does not contain function
19092 templates and at most one of a set of
19093 overloaded functions provides a unique
19094 match. */
19101 }
19107 }
19109 arg_strict |=
19111 }
19112 else
19117 /* For deduction from an init-list we need the actual list. */
19121 }
19123 /* for_each_template_parm callback that always returns 0. */
19125 static int
19127 {
19129 }
19131 /* for_each_template_parm any_fn callback to handle deduction of a template
19132 type argument from the type of an array bound. */
19134 static int
19136 {
19144 {
19150 }
19152 /* Keep walking. */
19154 }
19156 /* Try to deduce any not-yet-deduced template type arguments from the type of
19157 an array bound. This is handled separately from unify because 14.8.2.5 says
19158 "The type of a type parameter is only deduced from an array bound if it is
19159 not otherwise deduced." */
19161 static void
19163 {
19168 }
19170 /* Most parms like fn_type_unification.
19172 If SUBR is 1, we're being called recursively (to unify the
19173 arguments of a function or method parameter of a function
19174 template).
19176 CHECKS is a pointer to a vector of access checks encountered while
19177 substituting default template arguments. */
19179 static int
19181 tree full_targs,
19182 tree xparms,
19186 unification_kind_t strict,
19190 {
19195 tree parms;
19206 /* Reset the number of non-defaulted template arguments contained
19207 in TARGS. */
19210 again:
19218 {
19223 /* For a function parameter pack that occurs at the end of the
19224 parameter-declaration-list, the type A of each remaining
19225 argument of the call is compared with the type P of the
19226 declarator-id of the function parameter pack. */
19232 /* For a function parameter pack that does not occur at the
19233 end of the parameter-declaration-list, the type of the
19234 parameter pack is a non-deduced context. */
19241 explain_p))
19243 }
19248 {
19249 /* Unify the remaining arguments with the pack expansion type. */
19250 tree argvec;
19253 /* Allocate a TREE_VEC and copy in all of the arguments */
19258 /* Copy the parameter into parmvec. */
19264 /* Advance to the end of the list of parameters. */
19266 }
19268 /* Fail if we've reached the end of the parm list, and more args
19269 are present, and the parm list isn't variadic. */
19272 /* Fail if parms are left and they don't have default values and
19273 they aren't all deduced as empty packs (c++/57397). This is
19274 consistent with sufficient_parms_p. */
19277 {
19281 do
19282 {
19285 count++;
19287 }
19291 type_pack_p);
19292 }
19295 {
19296 tsubst_flags_t complain = (explain_p
19297 ? tf_warning_or_error
19302 {
19306 /* Clear the "incomplete" flags on all argument packs now so that
19307 substituting them into later default arguments works. */
19309 {
19312 }
19320 {
19325 }
19327 /* If this is an undeduced nontype parameter that depends on
19328 a type parameter, try another pass; its type may have been
19329 deduced from a later argument than the one from which
19330 this parameter can be deduced. */
19334 {
19337 }
19339 /* Core issue #226 (C++0x) [temp.deduct]:
19341 If a template argument has not been deduced, its
19342 default template argument, if any, is used.
19344 When we are in C++98 mode, TREE_PURPOSE will either
19345 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19346 to explicitly check cxx_dialect here. */
19348 /* OK, there is a default argument. Wait until after the
19349 conversion check to do substitution. */
19352 /* If the type parameter is a parameter pack, then it will
19353 be deduced to an empty parameter pack. */
19355 {
19356 tree arg;
19359 {
19362 }
19363 else
19370 }
19373 }
19375 /* DR 1391: All parameters have args, now check non-dependent parms for
19376 convertibility. */
19380 {
19386 /* For a function parameter pack that occurs at the end of the
19387 parameter-declaration-list, the type A of each remaining
19388 argument of the call is compared with the type P of the
19389 declarator-id of the function parameter pack. */
19395 /* For a function parameter pack that does not occur at the
19396 end of the parameter-declaration-list, the type of the
19397 parameter pack is a non-deduced context. */
19406 explain_p))
19408 }
19410 /* Now substitute into the default template arguments. */
19412 {
19436 else
19444 {
19446 /* The position of the first default template argument,
19447 is also the number of non-defaulted arguments in TARGS.
19448 Record that. */
19451 }
19452 }
19456 }
19462 }
19464 /* Subroutine of type_unification_real. Args are like the variables
19465 at the call site. ARG is an overloaded function (or template-id);
19466 we try deducing template args from each of the overloads, and if
19467 only one succeeds, we go with that. Modifies TARGS and returns
19468 true on success. */
19470 static bool
19472 tree targs,
19473 tree parm,
19474 tree arg,
19475 unification_kind_t strict,
19478 {
19485 {
19488 }
19489 else
19493 /* Handle `&x' where `x' is some static or non-static member
19494 function name. */
19500 /* Strip baselink information. */
19505 {
19506 /* If we got some explicit template args, we need to plug them into
19507 the affected templates before we try to unify, in case the
19508 explicit args will completely resolve the templates in question. */
19515 {
19528 {
19533 {
19536 }
19537 }
19540 }
19541 /* If no templates (or more than one) are fully resolved by the
19542 explicit arguments, this template-id is a non-deduced context; it
19543 could still be OK if we deduce all template arguments for the
19544 enclosing call through other arguments. */
19547 }
19550 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19551 -- but the deduction does not succeed because the expression is
19552 not just the function on its own. */
19554 else
19556 {
19561 {
19564 }
19565 }
19567 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19568 to function or pointer to member function argument if the set of
19569 overloaded functions does not contain function templates and at most
19570 one of a set of overloaded functions provides a unique match.
19572 So if we found multiple possibilities, we return success but don't
19573 deduce anything. */
19576 {
19580 {
19585 /* Don't forget explicit template arguments in a pack. */
19589 }
19590 }
19595 }
19597 /* Core DR 115: In contexts where deduction is done and fails, or in
19598 contexts where deduction is not done, if a template argument list is
19599 specified and it, along with any default template arguments, identifies
19600 a single function template specialization, then the template-id is an
19601 lvalue for the function template specialization. */
19603 tree
19605 {
19618 {
19621 }
19623 {
19626 }
19628 {
19631 }
19634 {
19638 /* If we got some explicit template args, we need to plug them into
19639 the affected templates before we try to unify, in case the
19640 explicit args will completely resolve the templates in question. */
19648 {
19661 {
19664 {
19667 }
19669 {
19672 }
19673 }
19674 }
19676 {
19684 {
19685 tree base
19688 }
19692 }
19694 /* There were no good options and at least one bad one, so let the
19695 user know what the problem is. */
19697 }
19699 }
19701 /* Subroutine of resolve_overloaded_unification; does deduction for a single
19702 overload. Fills TARGS with any deduced arguments, or error_mark_node if
19703 different overloads deduce different arguments for a given parm.
19704 ADDR_P is true if the expression for which deduction is being
19705 performed was of the form "& fn" rather than simply "fn".
19707 Returns 1 on success. */
19709 static int
19711 tree orig_targs,
19712 tree targs,
19713 tree parm,
19714 tree arg,
19715 unification_kind_t strict,
19719 {
19721 tree tempargs;
19727 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19728 to function or pointer to member function argument if the set of
19729 overloaded functions does not contain function templates and at most
19730 one of a set of overloaded functions provides a unique match.
19732 So if this is a template, just return success. */
19744 /* We don't copy orig_targs for this because if we have already deduced
19745 some template args from previous args, unify would complain when we
19746 try to deduce a template parameter for the same argument, even though
19747 there isn't really a conflict. */
19754 /* First make sure we didn't deduce anything that conflicts with
19755 explicitly specified args. */
19757 {
19764 /* Since we're unifying against ourselves, we will fill in
19765 template args used in the function parm list with our own
19766 template parms. Discard them. */
19769 {
19770 /* Check that the argument at each index of the deduced argument pack
19771 is equivalent to the corresponding explicitly specified argument.
19772 We may have deduced more arguments than were explicitly specified,
19773 and that's OK. */
19775 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
19776 that's wrong if we deduce the same argument pack from multiple
19777 function arguments: it's only incomplete the first time. */
19790 }
19793 }
19796 {
19801 }
19804 }
19806 /* PARM is a template class (perhaps with unbound template
19807 parameters). ARG is a fully instantiated type. If ARG can be
19808 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
19809 TARGS are as for unify. */
19811 static tree
19814 {
19815 tree copy_of_targs;
19825 /* We need to make a new template argument vector for the call to
19826 unify. If we used TARGS, we'd clutter it up with the result of
19827 the attempted unification, even if this class didn't work out.
19828 We also don't want to commit ourselves to all the unifications
19829 we've already done, since unification is supposed to be done on
19830 an argument-by-argument basis. In other words, consider the
19831 following pathological case:
19833 template <int I, int J, int K>
19834 struct S {};
19836 template <int I, int J>
19837 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
19839 template <int I, int J, int K>
19840 void f(S<I, J, K>, S<I, I, I>);
19842 void g() {
19843 S<0, 0, 0> s0;
19844 S<0, 1, 2> s2;
19846 f(s0, s2);
19847 }
19849 Now, by the time we consider the unification involving `s2', we
19850 already know that we must have `f<0, 0, 0>'. But, even though
19851 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
19852 because there are two ways to unify base classes of S<0, 1, 2>
19853 with S<I, I, I>. If we kept the already deduced knowledge, we
19854 would reject the possibility I=1. */
19858 {
19862 }
19864 /* If unification failed, we're done. */
19870 }
19872 /* Given a template type PARM and a class type ARG, find the unique
19873 base type in ARG that is an instance of PARM. We do not examine
19874 ARG itself; only its base-classes. If there is not exactly one
19875 appropriate base class, return NULL_TREE. PARM may be the type of
19876 a partial specialization, as well as a plain template type. Used
19877 by unify. */
19879 static enum template_base_result
19882 {
19884 tree binfo;
19890 {
19891 /* The type could not be completed. */
19894 }
19896 /* Walk in inheritance graph order. The search order is not
19897 important, and this avoids multiple walks of virtual bases. */
19899 {
19904 {
19905 /* If there is more than one satisfactory baseclass, then:
19907 [temp.deduct.call]
19909 If they yield more than one possible deduced A, the type
19910 deduction fails.
19912 applies. */
19914 {
19917 }
19920 }
19921 }
19925 }
19927 /* Returns the level of DECL, which declares a template parameter. */
19929 static int
19931 {
19933 {
19943 }
19945 }
19947 /* Decide whether ARG can be unified with PARM, considering only the
19948 cv-qualifiers of each type, given STRICT as documented for unify.
19949 Returns nonzero iff the unification is OK on that basis. */
19951 static int
19953 {
19959 {
19960 /* Although a CVR qualifier is ignored when being applied to a
19961 substituted template parameter ([8.3.2]/1 for example), that
19962 does not allow us to unify "const T" with "int&" because both
19963 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
19964 It is ok when we're allowing additional CV qualifiers
19965 at the outer level [14.8.2.1]/3,1st bullet. */
19975 }
19986 }
19988 /* Determines the LEVEL and INDEX for the template parameter PARM. */
19989 void
19991 {
19995 {
19998 }
19999 else
20000 {
20003 }
20004 }
20006 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20007 do { \
20008 if (unify (TP, TA, P, A, S, EP)) \
20009 return 1; \
20010 } while (0)
20012 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20013 expansion at the end of PACKED_PARMS. Returns 0 if the type
20014 deduction succeeds, 1 otherwise. STRICT is the same as in
20015 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20016 function call argument list. We'll need to adjust the arguments to make them
20017 types. SUBR tells us if this is from a recursive call to
20018 type_unification_real, or for comparing two template argument
20019 lists. */
20021 static int
20025 {
20026 tree parm
20032 /* Add in any args remembered from an earlier partial instantiation. */
20039 /* Determine the parameter packs we will be deducing from the
20040 pattern, and record their current deductions. */
20043 {
20047 /* Determine the index and level of this parameter pack. */
20050 /* Keep track of the parameter packs and their corresponding
20051 argument packs. */
20054 }
20056 /* Loop through all of the arguments that have not yet been
20057 unified and unify each with the pattern. */
20059 {
20060 tree parm;
20064 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20065 or the element of its argument pack at the current index if
20066 this argument was explicitly specified. */
20068 {
20077 {
20080 }
20082 }
20084 /* If we had explicit template arguments, substitute them into the
20085 pattern before deduction. */
20087 {
20088 /* Some arguments might still be unspecified or dependent. */
20096 NULL_TREE);
20101 }
20102 else
20105 /* Unify the pattern with the current argument. */
20107 explain_p))
20110 /* For each parameter pack, collect the deduced value. */
20112 {
20118 }
20119 }
20121 /* Verify that the results of unification with the parameter packs
20122 produce results consistent with what we've seen before, and make
20123 the deduced argument packs available. */
20125 {
20132 /* By default keep the original deduced argument pack.
20133 If necessary, more specific code is going to update the
20134 resulting deduced argument later down in this function. */
20138 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20139 actually deduce anything. */
20147 {
20148 /* If we had fewer function args than explicit template args,
20149 just use the explicits. */
20154 }
20157 {
20158 tree result;
20159 /* Build the deduced *_ARGUMENT_PACK. */
20161 {
20164 }
20165 else
20170 /* Note the deduced argument packs for this parameter
20171 pack. */
20173 }
20177 {
20178 /* We only had the explicitly-provided arguments before, but
20179 now we have a complete set of arguments. */
20185 }
20186 else
20187 {
20193 /* Inconsistent unification of this parameter pack. */
20195 bad_old_arg,
20196 bad_new_arg);
20197 }
20198 }
20201 }
20203 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20204 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20205 parameters and return value are as for unify. */
20207 static int
20211 {
20212 tree parm_max;
20213 tree arg_max;
20217 /* Our representation of array types uses "N - 1" as the
20218 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20219 not an integer constant. We cannot unify arbitrarily
20220 complex expressions, so we eliminate the MINUS_EXPRs
20221 here. */
20225 {
20228 }
20232 {
20233 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20234 trying to unify the type of a variable with the type
20235 of a template parameter. For example:
20237 template <unsigned int N>
20238 void f (char (&) [N]);
20239 int g();
20240 void h(int i) {
20241 char a[g(i)];
20242 f(a);
20243 }
20245 Here, the type of the ARG will be "int [g(i)]", and
20246 may be a SAVE_EXPR, etc. */
20250 }
20252 /* If only one of the bounds used a MINUS_EXPR, compensate
20253 by adding one to the other bound. */
20256 integer_type_node,
20257 parm_max,
20258 integer_one_node);
20261 integer_type_node,
20262 arg_max,
20263 integer_one_node);
20267 }
20269 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20273 static pa_kind_t
20275 {
20284 else
20286 }
20288 /* Deduce the value of template parameters. TPARMS is the (innermost)
20289 set of template parameters to a template. TARGS is the bindings
20290 for those template parameters, as determined thus far; TARGS may
20291 include template arguments for outer levels of template parameters
20292 as well. PARM is a parameter to a template function, or a
20293 subcomponent of that parameter; ARG is the corresponding argument.
20294 This function attempts to match PARM with ARG in a manner
20295 consistent with the existing assignments in TARGS. If more values
20296 are deduced, then TARGS is updated.
20298 Returns 0 if the type deduction succeeds, 1 otherwise. The
20299 parameter STRICT is a bitwise or of the following flags:
20301 UNIFY_ALLOW_NONE:
20302 Require an exact match between PARM and ARG.
20303 UNIFY_ALLOW_MORE_CV_QUAL:
20304 Allow the deduced ARG to be more cv-qualified (by qualification
20305 conversion) than ARG.
20306 UNIFY_ALLOW_LESS_CV_QUAL:
20307 Allow the deduced ARG to be less cv-qualified than ARG.
20308 UNIFY_ALLOW_DERIVED:
20309 Allow the deduced ARG to be a template base class of ARG,
20310 or a pointer to a template base class of the type pointed to by
20311 ARG.
20312 UNIFY_ALLOW_INTEGER:
20313 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20314 case for more information.
20315 UNIFY_ALLOW_OUTER_LEVEL:
20316 This is the outermost level of a deduction. Used to determine validity
20317 of qualification conversions. A valid qualification conversion must
20318 have const qualified pointers leading up to the inner type which
20319 requires additional CV quals, except at the outer level, where const
20320 is not required [conv.qual]. It would be normal to set this flag in
20321 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20322 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20323 This is the outermost level of a deduction, and PARM can be more CV
20324 qualified at this point.
20325 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20326 This is the outermost level of a deduction, and PARM can be less CV
20327 qualified at this point. */
20329 static int
20332 {
20334 tree targ;
20335 tree tparm;
20337 tsubst_flags_t complain = (explain_p
20338 ? tf_warning_or_error
20341 /* I don't think this will do the right thing with respect to types.
20342 But the only case I've seen it in so far has been array bounds, where
20343 signedness is the only information lost, and I think that will be
20344 okay. */
20352 /* We can't deduce anything from this, but we might get all the
20353 template args from other function args. */
20359 /* If PARM uses template parameters, then we can't bail out here,
20360 even if ARG == PARM, since we won't record unifications for the
20361 template parameters. We might need them if we're trying to
20362 figure out which of two things is more specialized. */
20366 /* Handle init lists early, so the rest of the function can assume
20367 we're dealing with a type. */
20369 {
20374 /* Replace T with std::initializer_list<T> for deduction. */
20381 /* We can only deduce from an initializer list argument if the
20382 parameter is std::initializer_list or an array; otherwise this
20383 is a non-deduced context. */
20388 else
20389 {
20391 /* Deduction is defined in terms of a single type, so just punt
20392 on the (bizarre) std::initializer_list<T...>. */
20395 }
20398 {
20405 {
20409 /* It should only be possible to get here for a call. */
20411 elt_strict |= maybe_adjust_types_for_deduction
20414 }
20417 explain_p);
20418 }
20422 {
20423 /* Also deduce from the length of the initializer list. */
20430 }
20432 /* If the std::initializer_list<T> deduction worked, replace the
20433 deduced A with std::initializer_list<A>. */
20435 {
20440 }
20442 }
20444 /* If parm and arg aren't the same kind of thing (template, type, or
20445 expression), fail early. */
20449 /* Immediately reject some pairs that won't unify because of
20450 cv-qualification mismatches. */
20453 /* It is the elements of the array which hold the cv quals of an array
20454 type, and the elements might be template type parms. We'll check
20455 when we recurse. */
20457 /* We check the cv-qualifiers when unifying with template type
20458 parameters below. We want to allow ARG `const T' to unify with
20459 PARM `T' for example, when computing which of two templates
20460 is more specialized, for example. */
20474 {
20478 /* In a type which contains a nested-name-specifier, template
20479 argument values cannot be deduced for template parameters used
20480 within the nested-name-specifier. */
20492 /* The PARM is not one we're trying to unify. Just check
20493 to see if it matches ARG. */
20494 {
20499 else
20501 }
20508 /* Check for mixed types and values. */
20516 {
20519 {
20520 /* First try to match ARG directly. */
20522 explain_p);
20524 {
20525 /* Otherwise, look for a suitable base of ARG, as below. */
20532 }
20533 }
20534 /* ARG must be constructed from a template class or a template
20535 template parameter. */
20540 /* Deduce arguments T, i from TT<T> or TT<i>. */
20546 /* Fall through to deduce template name. */
20547 }
20551 {
20552 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20554 /* Simple cases: Value already set, does match or doesn't. */
20559 }
20560 else
20561 {
20562 /* If PARM is `const T' and ARG is only `int', we don't have
20563 a match unless we are allowing additional qualification.
20564 If ARG is `const int' and PARM is just `T' that's OK;
20565 that binds `const int' to `T'. */
20570 /* Consider the case where ARG is `const volatile int' and
20571 PARM is `const T'. Then, T should be `volatile int'. */
20572 arg = cp_build_qualified_type_real
20577 /* Simple cases: Value already set, does match or doesn't. */
20583 /* Make sure that ARG is not a variable-sized array. (Note
20584 that were talking about variable-sized arrays (like
20585 `int[n]'), rather than arrays of unknown size (like
20586 `int[]').) We'll get very confused by such a type since
20587 the bound of the array is not constant, and therefore
20588 not mangleable. Besides, such types are not allowed in
20589 ISO C++, so we can do as we please here. We do allow
20590 them for 'auto' deduction, since that isn't ABI-exposed. */
20594 /* Strip typedefs as in convert_template_argument. */
20596 }
20598 /* If ARG is a parameter pack or an expansion, we cannot unify
20599 against it unless PARM is also a parameter pack. */
20604 /* If the argument deduction results is a METHOD_TYPE,
20605 then there is a problem.
20606 METHOD_TYPE doesn't map to any real C++ type the result of
20607 the deduction can not be of that type. */
20621 {
20622 /* The PARM is not one we're trying to unify. Just check
20623 to see if it matches ARG. */
20629 }
20635 {
20640 }
20642 /* [temp.deduct.type] If, in the declaration of a function template
20643 with a non-type template-parameter, the non-type
20644 template-parameter is used in an expression in the function
20645 parameter-list and, if the corresponding template-argument is
20646 deduced, the template-argument type shall match the type of the
20647 template-parameter exactly, except that a template-argument
20648 deduced from an array bound may be of any integral type.
20649 The non-type parameter might use already deduced type parameters. */
20652 {
20656 }
20659 /* Template-parameter dependent expression. Just accept it for now.
20660 It will later be processed in convert_template_argument. */
20661 ;
20667 /* Convert the ARG to the type of PARM; the deduced non-type
20668 template argument must exactly match the types of the
20669 corresponding parameter. */
20672 {
20673 /* We haven't deduced the type of this parameter yet. */
20675 /* We deduce from array bounds in try_array_deduction. */
20677 {
20678 /* Deduce it from the non-type argument. */
20683 }
20684 else
20685 /* Try again later. */
20687 }
20688 else
20691 /* If ARG is a parameter pack or an expansion, we cannot unify
20692 against it unless PARM is also a parameter pack. */
20697 {
20700 }
20705 {
20706 /* A pointer-to-member constant can be unified only with
20707 another constant. */
20711 /* Just unify the class member. It would be useless (and possibly
20712 wrong, depending on the strict flags) to unify also
20713 PTRMEM_CST_CLASS, because we want to be sure that both parm and
20714 arg refer to the same variable, even if through different
20715 classes. For instance:
20717 struct A { int x; };
20718 struct B : A { };
20720 Unification of &A::x and &B::x must succeed. */
20723 }
20726 {
20730 /* [temp.deduct.call]
20732 A can be another pointer or pointer to member type that can
20733 be converted to the deduced A via a qualification
20734 conversion (_conv.qual_).
20736 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
20737 This will allow for additional cv-qualification of the
20738 pointed-to types if appropriate. */
20741 /* The derived-to-base conversion only persists through one
20742 level of pointers. */
20747 }
20779 /* We have already checked cv-qualification at the top of the
20780 function. */
20784 /* As far as unification is concerned, this wins. Later checks
20785 will invalidate it if necessary. */
20788 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
20789 /* Type INTEGER_CST can come from ordinary constant template args. */
20801 {
20811 /* Check for pack expansions in the parameters. */
20813 {
20815 {
20817 /* We can unify against something with a trailing
20818 parameter pack. */
20820 else
20821 /* [temp.deduct.type]/9: If the template argument list of
20822 P contains a pack expansion that is not the last
20823 template argument, the entire template argument list
20824 is a non-deduced context. */
20826 }
20827 }
20829 /* If we don't have enough arguments to satisfy the parameters
20830 (not counting the pack expression at the end), or we have
20831 too many arguments for a parameter list that doesn't end in
20832 a pack expression, we can't unify. */
20838 /* Unify all of the parameters that precede the (optional)
20839 pack expression. */
20841 {
20846 }
20849 DEDUCE_EXACT,
20852 }
20860 {
20868 }
20873 {
20877 {
20878 /* First, we try to unify the PARM and ARG directly. */
20883 {
20884 /* Fallback to the special case allowed in
20885 [temp.deduct.call]:
20887 If P is a class, and P has the form
20888 template-id, then A can be a derived class of
20889 the deduced A. Likewise, if P is a pointer to
20890 a class of the form template-id, A can be a
20891 pointer to a derived class pointed to by the
20892 deduced A. */
20898 {
20899 /* Don't give the derived diagnostic if we're
20900 already dealing with the same template. */
20901 bool same_template
20907 }
20908 }
20909 }
20913 /* Perhaps PARM is something like S<U> and ARG is S<int>.
20914 Then, we should unify `int' and `U'. */
20916 else
20917 /* There's no chance of unification succeeding. */
20922 }
20929 {
20932 tree a;
20938 /* CV qualifications for methods can never be deduced, they must
20939 match exactly. We need to check them explicitly here,
20940 because type_unification_real treats them as any other
20941 cv-qualified parameter. */
20943 && (!check_cv_quals_for_unify
20971 {
20983 }
20986 }
20989 /* Unify a pointer to member with a pointer to member function, which
20990 deduces the type of the member as a function type. */
20992 {
20993 /* Check top-level cv qualifiers */
21001 /* Determine the type of the function we are unifying against. */
21005 }
21024 /* Matched cases are handled by the ARG == PARM test above. */
21028 /* We might get a variable as a non-type template argument in parm if the
21029 corresponding parameter is type-dependent. Make any necessary
21030 adjustments based on whether arg is a reference. */
21034 {
21039 }
21040 /* Now use the normal expression code to check whether they match. */
21051 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21052 or UNDERLYING_TYPE nodes. */
21056 /* Unification fails if we hit an error node. */
21061 {
21071 }
21072 /* FALLTHRU */
21075 /* An unresolved overload is a nondeduced context. */
21079 expr:
21080 /* We must be looking at an expression. This can happen with
21081 something like:
21083 template <int I>
21084 void foo(S<I>, S<I + 2>);
21086 This is a "nondeduced context":
21088 [deduct.type]
21090 The nondeduced contexts are:
21092 --A type that is a template-id in which one or more of
21093 the template-arguments is an expression that references
21094 a template-parameter.
21096 In these cases, we assume deduction succeeded, but don't
21097 actually infer any unifications. */
21102 else
21104 }
21105 }
21106 #undef RECUR_AND_CHECK_FAILURE
21107 \f
21108 /* Note that DECL can be defined in this translation unit, if
21109 required. */
21111 static void
21113 {
21114 tree clone;
21118 }
21120 /* Called if RESULT is explicitly instantiated, or is a member of an
21121 explicitly instantiated class. */
21123 void
21125 {
21128 /* If this entity has already been written out, it's too late to
21129 make any modifications. */
21133 /* For anonymous namespace we don't need to do anything. */
21135 {
21138 }
21141 /* The TREE_PUBLIC flag for function declarations will have been
21142 set correctly by tsubst. */
21145 /* This might have been set by an earlier implicit instantiation. */
21150 else
21151 {
21154 /* Always make artificials weak. */
21157 /* For WIN32 we also want to put explicit instantiations in
21158 linkonce sections. */
21161 }
21163 /* If EXTERN_P, then this function will not be emitted -- unless
21164 followed by an explicit instantiation, at which point its linkage
21165 will be adjusted. If !EXTERN_P, then this function will be
21166 emitted here. In neither circumstance do we want
21167 import_export_decl to adjust the linkage. */
21169 }
21171 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21172 important template arguments. If any are missing, we check whether
21173 they're important by using error_mark_node for substituting into any
21174 args that were used for partial ordering (the ones between ARGS and END)
21175 and seeing if it bubbles up. */
21177 static bool
21179 {
21184 {
21187 }
21189 {
21193 }
21195 }
21197 /* Given two function templates PAT1 and PAT2, return:
21199 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21200 -1 if PAT2 is more specialized than PAT1.
21201 0 if neither is more specialized.
21203 LEN indicates the number of parameters we should consider
21204 (defaulted parameters should not be considered).
21206 The 1998 std underspecified function template partial ordering, and
21207 DR214 addresses the issue. We take pairs of arguments, one from
21208 each of the templates, and deduce them against each other. One of
21209 the templates will be more specialized if all the *other*
21210 template's arguments deduce against its arguments and at least one
21211 of its arguments *does* *not* deduce against the other template's
21212 corresponding argument. Deduction is done as for class templates.
21213 The arguments used in deduction have reference and top level cv
21214 qualifiers removed. Iff both arguments were originally reference
21215 types *and* deduction succeeds in both directions, an lvalue reference
21216 wins against an rvalue reference and otherwise the template
21217 with the more cv-qualified argument wins for that pairing (if
21218 neither is more cv-qualified, they both are equal). Unlike regular
21219 deduction, after all the arguments have been deduced in this way,
21220 we do *not* verify the deduced template argument values can be
21221 substituted into non-deduced contexts.
21223 The logic can be a bit confusing here, because we look at deduce1 and
21224 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21225 can find template arguments for pat1 to make arg1 look like arg2, that
21226 means that arg2 is at least as specialized as arg1. */
21228 int
21230 {
21243 /* Remove the this parameter from non-static member functions. If
21244 one is a non-static member function and the other is not a static
21245 member function, remove the first parameter from that function
21246 also. This situation occurs for operator functions where we
21247 locate both a member function (with this pointer) and non-member
21248 operator (with explicit first operand). */
21250 {
21255 }
21257 {
21260 {
21261 len--;
21263 }
21264 }
21266 /* If only one is a conversion operator, they are unordered. */
21270 /* Consider the return type for a conversion function */
21272 {
21275 len++;
21276 }
21278 processing_template_decl++;
21284 /* Stop when an ellipsis is seen. */
21286 {
21297 {
21298 /* When both arguments are pack expansions, we need only
21299 unify the patterns themselves. */
21303 /* This is the last comparison we need to do. */
21305 }
21307 /* DR 1847: If a particular P contains no template-parameters that
21308 participate in template argument deduction, that P is not used to
21309 determine the ordering. */
21315 {
21319 }
21322 {
21326 }
21332 {
21338 /* Setup the parameter vector, which contains only ARG1. */
21341 /* Setup the argument vector, which contains the remaining
21342 arguments. */
21351 /* We cannot deduce in the other direction, because ARG1 is
21352 a pack expansion but ARG2 is not. */
21354 }
21356 {
21362 /* Setup the parameter vector, which contains only ARG1. */
21365 /* Setup the argument vector, which contains the remaining
21366 arguments. */
21375 /* We cannot deduce in the other direction, because ARG2 is
21376 a pack expansion but ARG1 is not.*/
21378 }
21380 else
21381 {
21382 /* The normal case, where neither argument is a pack
21383 expansion. */
21390 }
21392 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21393 arg2, then arg2 is not as specialized as arg1. */
21399 /* "If, for a given type, deduction succeeds in both directions
21400 (i.e., the types are identical after the transformations above)
21401 and both P and A were reference types (before being replaced with
21402 the type referred to above):
21403 - if the type from the argument template was an lvalue reference and
21404 the type from the parameter template was not, the argument type is
21405 considered to be more specialized than the other; otherwise,
21406 - if the type from the argument template is more cv-qualified
21407 than the type from the parameter template (as described above),
21408 the argument type is considered to be more specialized than the other;
21409 otherwise,
21410 - neither type is more specialized than the other." */
21413 {
21415 {
21418 else
21420 }
21422 {
21427 }
21428 }
21431 /* We've failed to deduce something in either direction.
21432 These must be unordered. */
21435 next:
21439 /* We have already processed all of the arguments in our
21440 handing of the pack expansion type. */
21445 }
21447 /* "In most cases, all template parameters must have values in order for
21448 deduction to succeed, but for partial ordering purposes a template
21449 parameter may remain without a value provided it is not used in the
21450 types being used for partial ordering."
21452 Thus, if we are missing any of the targs1 we need to substitute into
21453 origs1, then pat2 is not as specialized as pat1. This can happen when
21454 there is a nondeduced context. */
21460 processing_template_decl--;
21462 /* If both deductions succeed, the partial ordering selects the more
21463 constrained template. */
21465 {
21470 }
21472 /* All things being equal, if the next argument is a pack expansion
21473 for one function but not for the other, prefer the
21474 non-variadic function. FIXME this is bogus; see c++/41958. */
21478 {
21481 }
21487 else
21489 }
21491 /* Determine which of two partial specializations of TMPL is more
21492 specialized.
21494 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21495 to the first partial specialization. The TREE_PURPOSE is the
21496 innermost set of template parameters for the partial
21497 specialization. PAT2 is similar, but for the second template.
21499 Return 1 if the first partial specialization is more specialized;
21500 -1 if the second is more specialized; 0 if neither is more
21501 specialized.
21503 See [temp.class.order] for information about determining which of
21504 two templates is more specialized. */
21506 static int
21508 {
21509 tree targs;
21518 /* Just like what happens for functions, if we are ordering between
21519 different template specializations, we may encounter dependent
21520 types in the arguments, and we need our dependency check functions
21521 to behave correctly. */
21525 {
21528 }
21532 {
21535 }
21538 /* If both deductions succeed, the partial ordering selects the more
21539 constrained template. */
21543 /* In the case of a tie where at least one of the templates
21544 has a parameter pack at the end, the template with the most
21545 non-packed parameters wins. */
21547 && any_deductions
21550 {
21556 /* We don't count the pack expansion at the end. */
21566 }
21569 }
21571 /* Return the template arguments that will produce the function signature
21572 DECL from the function template FN, with the explicit template
21573 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21574 also match. Return NULL_TREE if no satisfactory arguments could be
21575 found. */
21577 static tree
21579 {
21583 tree decl_arg_types;
21586 tree arg;
21590 /* Never do unification on the 'this' parameter. */
21611 }
21613 /* Return the innermost template arguments that, when applied to a partial
21614 specialization SPEC_TMPL of TMPL, yield the ARGS.
21616 For example, suppose we have:
21618 template <class T, class U> struct S {};
21619 template <class T> struct S<T*, int> {};
21621 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21622 partial specialization and the ARGS will be {double*, int}. The resulting
21623 vector will be {double}, indicating that `T' is bound to `double'. */
21625 static tree
21627 {
21629 tree spec_args
21632 tree deduced_args;
21633 tree innermost_deduced_args;
21637 {
21641 innermost_deduced_args);
21642 }
21643 else
21647 again:
21656 {
21658 {
21664 }
21666 }
21670 {
21673 }
21675 /* Verify that nondeduced template arguments agree with the type
21676 obtained from argument deduction.
21678 For example:
21680 struct A { typedef int X; };
21681 template <class T, class U> struct C {};
21682 template <class T> struct C<T, typename T::X> {};
21684 Then with the instantiation `C<A, int>', we can deduce that
21685 `T' is `A' but unify () does not check whether `typename T::X'
21686 is `int'. */
21697 /* We only need to check the innermost arguments; the other
21698 arguments will always agree. */
21703 /* Now that we have bindings for all of the template arguments,
21704 ensure that the arguments deduced for the template template
21705 parameters have compatible template parameter lists. See the use
21706 of template_template_parm_bindings_ok_p in fn_type_unification
21707 for more information. */
21712 }
21714 // Compare two function templates T1 and T2 by deducing bindings
21715 // from one against the other. If both deductions succeed, compare
21716 // constraints to see which is more constrained.
21717 static int
21719 {
21724 {
21727 }
21730 {
21733 }
21735 // If both deductions succeed, then one may be more constrained.
21740 }
21742 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
21743 Return the TREE_LIST node with the most specialized template, if
21744 any. If there is no most specialized template, the error_mark_node
21745 is returned.
21747 Note that this function does not look at, or modify, the
21748 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
21749 returned is one of the elements of INSTANTIATIONS, callers may
21750 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
21751 and retrieve it from the value returned. */
21753 tree
21755 {
21762 {
21768 {
21769 /* Equally specialized, move to next function. If there
21770 is no next function, nothing's most specialized. */
21775 }
21776 }
21779 /* Now verify that champ is better than everything earlier in the
21780 instantiation list. */
21783 {
21786 }
21787 }
21789 processing_template_decl--;
21795 }
21797 /* If DECL is a specialization of some template, return the most
21798 general such template. Otherwise, returns NULL_TREE.
21800 For example, given:
21802 template <class T> struct S { template <class U> void f(U); };
21804 if TMPL is `template <class U> void S<int>::f(U)' this will return
21805 the full template. This function will not trace past partial
21806 specializations, however. For example, given in addition:
21808 template <class T> struct S<T*> { template <class U> void f(U); };
21810 if TMPL is `template <class U> void S<int*>::f(U)' this will return
21811 `template <class T> template <class U> S<T*>::f(U)'. */
21813 tree
21815 {
21817 {
21820 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
21821 template friend, or a FIELD_DECL for a capture pack. */
21824 }
21826 /* Look for more and more general templates. */
21828 {
21829 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
21830 (See cp-tree.h for details.) */
21839 /* Stop if we run into an explicitly specialized class template. */
21846 }
21849 }
21851 /* Return the most specialized of the template partial specializations
21852 which can produce TARGET, a specialization of some class or variable
21853 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
21854 a TEMPLATE_DECL node corresponding to the partial specialization, while
21855 the TREE_PURPOSE is the set of template arguments that must be
21856 substituted into the template pattern in order to generate TARGET.
21858 If the choice of partial specialization is ambiguous, a diagnostic
21859 is issued, and the error_mark_node is returned. If there are no
21860 partial specializations matching TARGET, then NULL_TREE is
21861 returned, indicating that the primary template should be used. */
21863 static tree
21865 {
21867 tree t;
21868 tree champ;
21875 {
21879 }
21881 {
21884 }
21886 {
21890 }
21891 else
21896 /* For determining which partial specialization to use, only the
21897 innermost args are interesting. */
21899 {
21902 }
21905 {
21906 tree spec_args;
21910 {
21911 /* Substitute in the template args from the enclosing class. */
21915 }
21922 {
21926 /* Keep the candidate only if the constraints are satisfied,
21927 or if we're not compiling with concepts. */
21930 {
21933 }
21934 }
21935 }
21945 {
21948 ;
21949 else
21950 {
21952 {
21955 {
21958 }
21959 }
21961 }
21962 }
21966 {
21969 {
21972 }
21973 }
21976 {
21983 else
21987 {
21992 }
21995 }
21998 }
22000 /* Explicitly instantiate DECL. */
22002 void
22004 {
22009 /* An error occurred, for which grokdeclarator has already issued
22010 an appropriate message. */
22013 {
22016 }
22022 {
22023 /* There is an asymmetry here in the way VAR_DECLs and
22024 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22025 the latter, the DECL we get back will be marked as a
22026 template instantiation, and the appropriate
22027 DECL_TEMPLATE_INFO will be set up. This does not happen for
22028 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22029 should handle VAR_DECLs as it currently handles
22030 FUNCTION_DECLs. */
22032 {
22035 }
22038 {
22041 }
22043 {
22048 }
22049 }
22051 {
22054 }
22055 else
22058 /* Check for various error cases. Note that if the explicit
22059 instantiation is valid the RESULT will currently be marked as an
22060 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22061 until we get here. */
22064 {
22065 /* DR 259 [temp.spec].
22067 Both an explicit instantiation and a declaration of an explicit
22068 specialization shall not appear in a program unless the explicit
22069 instantiation follows a declaration of the explicit specialization.
22071 For a given set of template parameters, if an explicit
22072 instantiation of a template appears after a declaration of an
22073 explicit specialization for that template, the explicit
22074 instantiation has no effect. */
22076 }
22078 {
22079 /* [temp.spec]
22081 No program shall explicitly instantiate any template more
22082 than once.
22084 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22085 the first instantiation was `extern' and the second is not,
22086 and EXTERN_P for the opposite case. */
22089 /* If an "extern" explicit instantiation follows an ordinary
22090 explicit instantiation, the template is instantiated. */
22093 }
22095 {
22098 }
22100 {
22103 }
22106 ;
22108 {
22111 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22114 }
22115 else
22123 }
22125 static void
22127 {
22133 {
22136 }
22137 }
22139 /* Called from do_type_instantiation through binding_table_foreach to
22140 do recursive instantiation for the type bound in ENTRY. */
22141 static void
22143 {
22149 }
22151 /* Perform an explicit instantiation of template class T. STORAGE, if
22152 non-null, is the RID for extern, inline or static. COMPLAIN is
22153 nonzero if this is called from the parser, zero if called recursively,
22154 since the standard is unclear (as detailed below). */
22156 void
22158 {
22168 {
22169 tree tmpl =
22173 else
22176 }
22181 {
22184 t);
22186 }
22189 {
22191 {
22193 {
22196 "ISO C++ 1998 forbids the use of %<extern%> on "
22198 }
22199 else
22201 "ISO C++ forbids the use of %qE"
22203 }
22211 else
22212 {
22214 storage);
22216 }
22217 }
22220 {
22221 /* DR 259 [temp.spec].
22223 Both an explicit instantiation and a declaration of an explicit
22224 specialization shall not appear in a program unless the explicit
22225 instantiation follows a declaration of the explicit specialization.
22227 For a given set of template parameters, if an explicit
22228 instantiation of a template appears after a declaration of an
22229 explicit specialization for that template, the explicit
22230 instantiation has no effect. */
22232 }
22234 {
22235 /* [temp.spec]
22237 No program shall explicitly instantiate any template more
22238 than once.
22240 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22241 instantiation was `extern'. If EXTERN_P then the second is.
22242 These cases are OK. */
22249 /* If we've already instantiated the template, just return now. */
22252 }
22260 /* In contrast to implicit instantiation, where only the
22261 declarations, and not the definitions, of members are
22262 instantiated, we have here:
22264 [temp.explicit]
22266 The explicit instantiation of a class template specialization
22267 implies the instantiation of all of its members not
22268 previously explicitly specialized in the translation unit
22269 containing the explicit instantiation.
22271 Of course, we can't instantiate member template classes, since we
22272 don't have any arguments for them. Note that the standard is
22273 unclear on whether the instantiation of the members are
22274 *explicit* instantiations or not. However, the most natural
22275 interpretation is that it should be an explicit
22276 instantiation. */
22280 && !static_p
22283 {
22288 }
22293 }
22295 /* Given a function DECL, which is a specialization of TMPL, modify
22296 DECL to be a re-instantiation of TMPL with the same template
22297 arguments. TMPL should be the template into which tsubst'ing
22298 should occur for DECL, not the most general template.
22300 One reason for doing this is a scenario like this:
22302 template <class T>
22303 void f(const T&, int i);
22305 void g() { f(3, 7); }
22307 template <class T>
22308 void f(const T& t, const int i) { }
22310 Note that when the template is first instantiated, with
22311 instantiate_template, the resulting DECL will have no name for the
22312 first parameter, and the wrong type for the second. So, when we go
22313 to instantiate the DECL, we regenerate it. */
22315 static void
22317 {
22318 /* The arguments used to instantiate DECL, from the most general
22319 template. */
22320 tree code_pattern;
22324 /* Make sure that we can see identifiers, and compute access
22325 correctly. */
22329 {
22330 tree decl_parm;
22331 tree pattern_parm;
22332 tree specs;
22346 specs);
22348 /* Merge parameter declarations. */
22351 pattern_parm
22355 {
22356 tree parm_type;
22357 tree attributes;
22362 NULL_TREE);
22368 {
22371 }
22374 }
22375 /* Merge any parameters that match with the function parameter
22376 pack. */
22378 {
22380 tree expanded_types;
22381 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22382 the parameters in this function parameter pack. */
22387 {
22388 tree parm_type;
22389 tree attributes;
22392 /* Rename the parameter to include the index. */
22401 {
22404 }
22406 }
22407 }
22408 /* Merge additional specifiers from the CODE_PATTERN. */
22412 }
22414 {
22422 }
22423 else
22427 }
22429 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22430 substituted to get DECL. */
22432 tree
22434 {
22437 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22438 for the instantiation. This is not always the most general
22439 template. Consider, for example:
22441 template <class T>
22442 struct S { template <class U> void f();
22443 template <> void f<int>(); };
22445 and an instantiation of S<double>::f<int>. We want TD to be the
22446 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22448 more general template. */
22450 /* We must also deal with friend templates. Given:
22452 template <class T> struct S {
22453 template <class U> friend void f() {};
22454 };
22456 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22457 so far as the language is concerned, but that's still
22458 where we get the pattern for the instantiation from. On
22459 other hand, if the definition comes outside the class, say:
22461 template <class T> struct S {
22462 template <class U> friend void f();
22463 };
22464 template <class U> friend void f() {}
22466 we don't need to look any further. That's what the check for
22467 DECL_INITIAL is for. */
22471 {
22472 /* The present template, TD, should not be a definition. If it
22473 were a definition, we should be using it! Note that we
22474 cannot restructure the loop to just keep going until we find
22475 a template with a definition, since that might go too far if
22476 a specialization was declared, but not defined. */
22478 /* Fetch the more general template. */
22480 }
22483 }
22485 /* Returns true if we need to instantiate this template instance even if we
22486 know we aren't going to emit it. */
22488 bool
22490 {
22491 /* We always instantiate inline functions so that we can inline them. An
22492 explicit instantiation declaration prohibits implicit instantiation of
22493 non-inline functions. With high levels of optimization, we would
22494 normally inline non-inline functions -- but we're not allowed to do
22495 that for "extern template" functions. Therefore, we check
22496 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22500 /* And we need to instantiate static data members so that
22501 their initializers are available in integral constant
22502 expressions. */
22505 }
22507 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22508 instantiate it now, modifying TREE_TYPE (fn). Returns false on
22509 error, true otherwise. */
22511 bool
22513 {
22516 /* Don't instantiate a noexcept-specification from template context. */
22531 {
22537 {
22538 /* If hash_set::add returns true, the element was already there. */
22543 fn);
22545 }
22547 {
22562 }
22563 else
22573 }
22576 {
22579 else
22581 }
22584 }
22586 /* Produce the definition of D, a _DECL generated from a template. If
22587 DEFER_OK is true, then we don't have to actually do the
22588 instantiation now; we just have to do it sometime. Normally it is
22589 an error if this is an explicit instantiation but D is undefined.
22590 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22591 instantiated class template. */
22593 tree
22595 {
22597 tree gen_args;
22598 tree args;
22599 tree td;
22600 tree code_pattern;
22601 tree spec;
22602 tree gen_tmpl;
22610 /* This function should only be used to instantiate templates for
22611 functions and static member variables. */
22614 /* A concept is never instantiated. */
22617 /* Variables are never deferred; if instantiation is required, they
22618 are instantiated right away. That allows for better code in the
22619 case that an expression refers to the value of the variable --
22620 if the variable has a constant value the referring expression can
22621 take advantage of that fact. */
22625 /* Don't instantiate cloned functions. Instead, instantiate the
22626 functions they cloned. */
22634 /* D has already been instantiated or explicitly specialized, so
22635 there's nothing for us to do here.
22637 It might seem reasonable to check whether or not D is an explicit
22638 instantiation, and, if so, stop here. But when an explicit
22639 instantiation is deferred until the end of the compilation,
22640 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22641 the instantiation. */
22644 /* Check to see whether we know that this template will be
22645 instantiated in some other file, as with "extern template"
22646 extension. */
22649 /* In general, we do not instantiate such templates. */
22657 /* We should already have the extra args. */
22660 /* And what's in the hash table should match D. */
22664 /* This needs to happen before any tsubsting. */
22670 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
22671 for the instantiation. */
22676 {
22677 /* Look up an explicit specialization, if any. */
22681 {
22684 }
22685 }
22689 /* We should never be trying to instantiate a member of a class
22690 template or partial specialization. */
22695 /* In the case of a friend template whose definition is provided
22696 outside the class, we may have too many arguments. Drop the
22697 ones we don't need. The same is true for specializations. */
22698 args = get_innermost_template_args
22702 {
22708 }
22709 else
22710 {
22715 else
22717 }
22719 /* We may be in the middle of deferred access check. Disable it now. */
22722 /* Unless an explicit instantiation directive has already determined
22723 the linkage of D, remember that a definition is available for
22724 this entity. */
22734 /* If D is a member of an explicitly instantiated class template,
22735 and no definition is available, treat it like an implicit
22736 instantiation. */
22739 {
22740 /* Leave linkage flags alone on instantiations with anonymous
22741 visibility. */
22743 {
22746 }
22748 }
22750 /* Defer all other templates, unless we have been explicitly
22751 forbidden from doing so. */
22753 template. */
22754 ! pattern_defined
22755 /* If it's OK to postpone instantiation, do so. */
22756 || defer_ok
22757 /* If this is a static data member that will be defined
22758 elsewhere, we don't want to instantiate the entire data
22759 member, but we do want to instantiate the initializer so that
22760 we can substitute that elsewhere. */
22762 /* Handle here a deleted function too, avoid generating
22763 its body (c++/61080). */
22765 {
22766 /* The definition of the static data member is now required so
22767 we must substitute the initializer. */
22771 {
22772 tree ns;
22773 tree init;
22782 args,
22785 /* If instantiating the initializer involved instantiating this
22786 again, don't call cp_finish_decl twice. */
22788 {
22789 /* Make sure the initializer is still constant, in case of
22790 circular dependency (template/instantiate6.C). */
22791 const_init
22795 LOOKUP_ONLYCONVERTING);
22796 }
22800 }
22802 /* We restore the source position here because it's used by
22803 add_pending_template. */
22809 /* [temp.explicit]
22811 The definition of a non-exported function template, a
22812 non-exported member function template, or a non-exported
22813 member function or static data member of a class template
22814 shall be present in every translation unit in which it is
22815 explicitly instantiated. */
22819 /* If we're in unevaluated context, we just wanted to get the
22820 constant value; this isn't an odr use, so don't queue
22821 a full instantiation. */
22824 /* ??? Historically, we have instantiated inline functions, even
22825 when marked as "extern template". */
22829 }
22830 /* Tell the repository that D is available in this translation unit
22831 -- and see if it is supposed to be instantiated here. */
22833 {
22834 /* In a PCH file, despite the fact that the repository hasn't
22835 requested instantiation in the PCH it is still possible that
22836 an instantiation will be required in a file that includes the
22837 PCH. */
22840 /* Instantiate inline functions so that the inliner can do its
22841 job, even though we'll not be emitting a copy of this
22842 function. */
22845 }
22848 tree fn_context;
22859 else
22860 {
22864 }
22866 /* Mark D as instantiated so that recursive calls to
22867 instantiate_decl do not try to instantiate it again. */
22870 /* Regenerate the declaration in case the template has been modified
22871 by a subsequent redeclaration. */
22874 /* We already set the file and line above. Reset them now in case
22875 they changed as a result of calling regenerate_decl_from_template. */
22879 {
22880 tree init;
22883 /* Clear out DECL_RTL; whatever was there before may not be right
22884 since we've reset the type of the declaration. */
22888 /* The initializer is placed in DECL_INITIAL by
22889 regenerate_decl_from_template so we don't need to
22890 push/pop_access_scope again here. Pull it out so that
22891 cp_finish_decl can process it. */
22896 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
22897 initializer. That function will defer actual emission until
22898 we have a chance to determine linkage. */
22901 /* Enter the scope of D so that access-checking works correctly. */
22914 }
22918 {
22920 tree tmpl_parm;
22921 tree spec_parm;
22925 /* Save away the current list, in case we are instantiating one
22926 template from within the body of another. */
22929 /* Set up the list of local specializations. */
22932 /* Set up context. */
22936 else
22937 {
22939 {
22940 /* When instantiating a lambda's templated function
22941 operator, we need to push the non-lambda class scope
22942 of the lambda itself so that the nested function
22943 stack is sufficiently correct to deal with this
22944 capture. */
22946 do
22951 }
22953 }
22955 /* Some typedefs referenced from within the template code need to be
22956 access checked at template instantiation time, i.e now. These
22957 types were added to the template at parsing time. Let's get those
22958 and perform the access checks then. */
22960 args);
22962 /* Create substitution entries for the parameters. */
22966 {
22970 }
22972 {
22974 {
22977 }
22978 else
22979 {
22980 /* Register the (value) argument pack as a specialization of
22981 TMPL_PARM, then move on. */
22984 }
22985 }
22988 /* Substitute into the body of the function. */
22992 else
22993 {
22998 /* Set the current input_location to the end of the function
22999 so that finish_function knows where we are. */
23000 input_location
23003 /* Remember if we saw an infinite loop in the template. */
23004 current_function_infinite_loop
23006 }
23008 /* We don't need the local specializations any more. */
23012 /* Finish the function. */
23016 else
23017 {
23020 }
23026 }
23028 /* We're not deferring instantiation any more. */
23033 else
23039 out:
23048 }
23050 /* Run through the list of templates that we wish we could
23051 instantiate, and instantiate any we can. RETRIES is the
23052 number of times we retry pending template instantiation. */
23054 void
23056 {
23060 /* Instantiating templates may trigger vtable generation. This in turn
23061 may require further template instantiations. We place a limit here
23062 to avoid infinite loop. */
23064 {
23068 "template instantiation depth exceeds maximum of %d"
23069 " instantiating %q+D, possibly from virtual table generation"
23073 /* Pretend that we defined it. */
23076 }
23078 do
23079 {
23084 {
23089 {
23091 {
23106 }
23109 }
23110 else
23111 {
23114 {
23115 instantiation
23121 }
23125 }
23128 /* If INSTANTIATION has been instantiated, then we don't
23129 need to consider it again in the future. */
23131 else
23132 {
23135 }
23138 }
23140 }
23144 }
23146 /* Substitute ARGVEC into T, which is a list of initializers for
23147 either base class or a non-static data member. The TREE_PURPOSEs
23148 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23149 instantiate_decl. */
23151 static tree
23153 {
23157 {
23158 tree decl;
23159 tree init;
23165 {
23166 tree expr;
23167 tree arg;
23169 /* Expand the base class expansion type into separate base
23170 classes. */
23172 tf_warning_or_error,
23173 NULL_TREE);
23177 /* We'll be building separate TREE_LISTs of arguments for
23178 each base. */
23184 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23185 expand each argument in the TREE_VALUE of t. */
23192 /* VOID_TYPE_NODE is used to indicate
23193 value-initialization. */
23194 {
23197 }
23198 else
23199 {
23200 /* Substitute parameter packs into each argument in the
23201 TREE_LIST. */
23204 {
23205 tree expanded_exprs;
23207 /* Expand the argument. */
23209 expanded_exprs
23211 tf_warning_or_error,
23212 NULL_TREE);
23216 /* Prepend each of the expanded expressions to the
23217 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23219 {
23224 }
23225 }
23228 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23229 since we built them backwards. */
23231 {
23234 }
23235 }
23236 }
23239 {
23241 {
23245 }
23246 else
23247 {
23248 tree tmp;
23263 /* If we had an initializer but it instantiated to nothing,
23264 value-initialize the object. This will only occur when
23265 the initializer was a pack expansion where the parameter
23266 packs used in that expansion were of length zero. */
23269 }
23272 {
23276 }
23277 }
23278 }
23280 }
23282 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23284 static void
23286 {
23291 else
23293 }
23295 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23296 is the instantiation (which should have been created with
23297 start_enum) and ARGS are the template arguments to use. */
23299 static void
23301 {
23302 tree e;
23308 {
23309 tree value;
23310 tree decl;
23313 /* Note that in a template enum, the TREE_VALUE is the
23314 CONST_DECL, not the corresponding INTEGER_CST. */
23319 /* Give this enumeration constant the correct access. */
23322 /* Actually build the enumerator itself. Here we're assuming that
23323 enumerators can't have dependent attributes. */
23326 }
23336 }
23338 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23339 its type -- but without substituting the innermost set of template
23340 arguments. So, innermost set of template parameters will appear in
23341 the type. */
23343 tree
23345 {
23346 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23348 }
23350 /* Return truthvalue if we're processing a template different from
23351 the last one involved in diagnostics. */
23352 bool
23354 {
23356 }
23358 /* Remember current template involved in diagnostics. */
23359 void
23361 {
23363 }
23367 {
23369 }
23371 /* Return TRUE if current_function_decl is being instantiated, false
23372 otherwise. */
23374 bool
23376 {
23379 }
23381 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23382 type. Return zero for ok, nonzero for disallowed. Issue error and
23383 warning messages under control of COMPLAIN. */
23385 static int
23387 {
23402 /* A bound template template parm could later be instantiated to have a valid
23403 nontype parm type via an alias template. */
23409 {
23412 else
23414 type);
23415 }
23417 }
23419 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23420 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23422 static bool
23424 {
23425 tree scope;
23427 /* [temp.dep.type]
23429 A type is dependent if it is:
23431 -- a template parameter. Template template parameters are types
23432 for us (since TYPE_P holds true for them) so we handle
23433 them here. */
23437 /* -- a qualified-id with a nested-name-specifier which contains a
23438 class-name that names a dependent type or whose unqualified-id
23439 names a dependent type. */
23443 /* An alias template specialization can be dependent even if the
23444 resulting type is not. */
23448 /* -- a cv-qualified type where the cv-unqualified type is
23449 dependent.
23450 No code is necessary for this bullet; the code below handles
23451 cv-qualified types, and we don't want to strip aliases with
23452 TYPE_MAIN_VARIANT because of DR 1558. */
23453 /* -- a compound type constructed from any dependent type. */
23463 {
23464 tree arg_type;
23469 arg_type;
23474 {
23475 /* A value-dependent noexcept-specifier makes the type dependent. */
23480 }
23482 }
23483 /* -- an array type constructed from any dependent type or whose
23484 size is specified by a constant expression that is
23485 value-dependent.
23487 We checked for type- and value-dependence of the bounds in
23488 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23490 {
23495 }
23497 /* -- a template-id in which either the template name is a template
23498 parameter ... */
23501 /* ... or any of the template arguments is a dependent type or
23502 an expression that is type-dependent or value-dependent. */
23504 && (any_dependent_template_arguments_p
23508 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23509 dependent; if the argument of the `typeof' expression is not
23510 type-dependent, then it should already been have resolved. */
23516 /* A template argument pack is dependent if any of its packed
23517 arguments are. */
23519 {
23525 }
23527 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23528 be template parameters. */
23535 /* The standard does not specifically mention types that are local
23536 to template functions or local classes, but they should be
23537 considered dependent too. For example:
23539 template <int I> void f() {
23540 enum E { a = I };
23541 S<sizeof (E)> s;
23542 }
23544 The size of `E' cannot be known until the value of `I' has been
23545 determined. Therefore, `E' must be considered dependent. */
23549 /* Don't use type_dependent_expression_p here, as it can lead
23550 to infinite recursion trying to determine whether a lambda
23551 nested in a lambda is dependent (c++/47687). */
23555 && (any_dependent_template_arguments_p
23559 /* Other types are non-dependent. */
23561 }
23563 /* Returns TRUE if TYPE is dependent, in the sense of
23564 [temp.dep.type]. Note that a NULL type is considered dependent. */
23566 bool
23568 {
23569 /* If there are no template parameters in scope, then there can't be
23570 any dependent types. */
23572 {
23573 /* If we are not processing a template, then nobody should be
23574 providing us with a dependent type. */
23578 }
23580 /* If the type is NULL, we have not computed a type for the entity
23581 in question; in that case, the type is dependent. */
23585 /* Erroneous types can be considered non-dependent. */
23589 /* Getting here with global_type_node means we improperly called this
23590 function on the TREE_TYPE of an IDENTIFIER_NODE. */
23593 /* If we have not already computed the appropriate value for TYPE,
23594 do so now. */
23596 {
23599 }
23602 }
23604 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23605 lookup. In other words, a dependent type that is not the current
23606 instantiation. */
23608 bool
23610 {
23613 }
23615 /* T is a SCOPE_REF; return whether we need to consider it
23616 instantiation-dependent so that we can check access at instantiation
23617 time even though we know which member it resolves to. */
23619 static bool
23621 {
23627 else
23629 }
23631 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23632 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23633 expression. */
23635 /* Note that this predicate is not appropriate for general expressions;
23636 only constant expressions (that satisfy potential_constant_expression)
23637 can be tested for value dependence. */
23639 bool
23641 {
23645 /* A name declared with a dependent type. */
23650 {
23652 /* A dependent member function of the current instantiation. */
23656 /* A dependent member function of the current instantiation. */
23663 /* A name that has not been looked up -- must be dependent. */
23667 /* A non-type template parm. */
23671 /* A non-type template parm. */
23677 /* A constant with literal type and is initialized
23678 with an expression that is value-dependent.
23680 Note that a non-dependent parenthesized initializer will have
23681 already been replaced with its constant value, so if we see
23682 a TREE_LIST it must be dependent. */
23686 /* cp_finish_decl doesn't fold reference initializers. */
23692 {
23696 }
23704 /* These expressions are value-dependent if the type to which
23705 the cast occurs is dependent or the expression being casted
23706 is value-dependent. */
23707 {
23713 /* A functional cast has a list of operands. */
23716 {
23717 /* If there are no operands, it must be an expression such
23718 as "int()". This should not happen for aggregate types
23719 because it would form non-constant expressions. */
23724 }
23730 }
23735 /* FALLTHRU */
23738 /* A `sizeof' expression is value-dependent if the operand is
23739 type-dependent or is a pack expansion. */
23748 /* An 'encode' expression is value-dependent if the operand is
23749 type-dependent. */
23758 /* All instantiation-dependent expressions should also be considered
23759 value-dependent. */
23767 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
23768 is value-dependent. */
23769 {
23778 }
23781 {
23785 }
23796 {
23800 }
23803 /* Treat all requires-expressions as value-dependent so
23804 we don't try to fold them. */
23811 {
23818 {
23820 /* In a call to a constexpr member function, look through the
23821 implicit ADDR_EXPR on the object argument so that it doesn't
23822 cause the call to be considered value-dependent. We also
23823 look through it in potential_constant_expression. */
23830 }
23832 }
23835 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
23836 type-dependent. */
23841 {
23843 tree val;
23850 }
23853 /* Treat a GNU statement expression as dependent to avoid crashing
23854 under instantiate_non_dependent_expr; it can't be constant. */
23858 /* A constant expression is value-dependent if any subexpression is
23859 value-dependent. */
23861 {
23868 {
23872 {
23875 /* In some cases, some of the operands may be missing.
23876 (For example, in the case of PREDECREMENT_EXPR, the
23877 amount to increment by may be missing.) That doesn't
23878 make the expression dependent. */
23881 }
23882 }
23886 }
23888 }
23890 /* The expression is not value-dependent. */
23892 }
23894 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
23895 [temp.dep.expr]. Note that an expression with no type is
23896 considered dependent. Other parts of the compiler arrange for an
23897 expression with type-dependent subexpressions to have no type, so
23898 this function doesn't have to be fully recursive. */
23900 bool
23902 {
23909 /* An unresolved name is always dependent. */
23915 /* A fold expression is type-dependent. */
23922 /* Some expression forms are never type-dependent. */
23936 /* The types of these expressions depends only on the type to which
23937 the cast occurs. */
23946 /* The types of these expressions depends only on the type created
23947 by the expression. */
23950 {
23951 /* For NEW_EXPR tree nodes created inside a template, either
23952 the object type itself or a TREE_LIST may appear as the
23953 operand 1. */
23956 /* This is an array type. We need to check array dimensions
23957 as well. */
23959 || value_dependent_expression_p
23961 else
23963 }
23966 {
23970 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
23971 contains an identifier associated by name lookup with one or more
23972 declarations declared with a dependent type, or...a
23973 nested-name-specifier or qualified-id that names a member of an
23974 unknown specialization. */
23977 }
23987 {
23988 tree elt;
23992 {
23995 }
23997 }
23999 /* A static data member of the current instantiation with incomplete
24000 array type is type-dependent, as the definition and specializations
24001 can have different bounds. */
24008 /* An array of unknown bound depending on a variadic parameter, eg:
24010 template<typename... Args>
24011 void foo (Args... args)
24012 {
24013 int arr[] = { args... };
24014 }
24016 template<int... vals>
24017 void bar ()
24018 {
24019 int arr[] = { vals... };
24020 }
24022 If the array has no length and has an initializer, it must be that
24023 we couldn't determine its length in cp_complete_array_type because
24024 it is dependent. */
24032 /* A function or variable template-id is type-dependent if it has any
24033 dependent template arguments. */
24037 {
24038 /* Consider the innermost template arguments, since those are the ones
24039 that come from the template-id; the template arguments for the
24040 enclosing class do not make it type-dependent unless they are used in
24041 the type of the decl. */
24043 && (any_dependent_template_arguments_p
24047 /* Otherwise, if the decl isn't from a dependent scope, it can't be
24048 type-dependent. Checking this is important for functions with auto
24049 return type, which looks like a dependent type. */
24056 {
24060 }
24061 }
24063 /* Always dependent, on the number of arguments if nothing else. */
24068 {
24073 {
24079 }
24080 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24085 {
24090 }
24093 {
24100 }
24110 }
24114 /* Dependent type attributes might not have made it from the decl to
24115 the type yet. */
24121 }
24123 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24124 type-dependent if the expression refers to a member of the current
24125 instantiation and the type of the referenced member is dependent, or the
24126 class member access expression refers to a member of an unknown
24127 specialization.
24129 This function returns true if the OBJECT in such a class member access
24130 expression is of an unknown specialization. */
24132 bool
24134 {
24135 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24136 dependent. */
24141 }
24143 /* walk_tree callback function for instantiation_dependent_expression_p,
24144 below. Returns non-zero if a dependent subexpression is found. */
24146 static tree
24149 {
24151 {
24152 /* We don't have to worry about decltype currently because decltype
24153 of an instantiation-dependent expr is a dependent type. This
24154 might change depending on the resolution of DR 1172. */
24157 }
24160 {
24161 /* Don't treat an argument list as dependent just because it has no
24162 TREE_TYPE. */
24170 /* Handle expressions with type operands. */
24175 {
24180 {
24183 else
24184 {
24187 }
24188 }
24190 }
24194 /* In a template, finish_class_member_access_expr creates a
24195 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24196 type-dependent, so that we can check access control at
24197 instantiation time (PR 42277). See also Core issue 1273. */
24204 else
24207 /* Treat statement-expressions as dependent. */
24211 /* Treat requires-expressions as dependent. */
24216 /* Treat calls to function concepts as dependent. */
24222 /* And variable concepts. */
24229 }
24233 else
24235 }
24237 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24238 sense defined by the ABI:
24240 "An expression is instantiation-dependent if it is type-dependent
24241 or value-dependent, or it has a subexpression that is type-dependent
24242 or value-dependent."
24244 Except don't actually check value-dependence for unevaluated expressions,
24245 because in sizeof(i) we don't care about the value of i. Checking
24246 type-dependence will in turn check value-dependence of array bounds/template
24247 arguments as needed. */
24249 bool
24251 {
24252 tree result;
24263 }
24265 /* As above, but also check value-dependence of the expression as a whole. */
24267 bool
24269 {
24272 }
24274 /* Like type_dependent_expression_p, but it also works while not processing
24275 a template definition, i.e. during substitution or mangling. */
24277 bool
24279 {
24285 }
24287 /* Returns TRUE if ARGS contains a type-dependent expression. */
24289 bool
24291 {
24293 tree arg;
24296 {
24299 }
24301 }
24303 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24304 expressions) contains any type-dependent expressions. */
24306 bool
24308 {
24314 }
24316 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24317 expressions) contains any value-dependent expressions. */
24319 bool
24321 {
24327 }
24329 /* Returns TRUE if the ARG (a template argument) is dependent. */
24331 bool
24333 {
24337 /* Assume a template argument that was wrongly written by the user
24338 is dependent. This is consistent with what
24339 any_dependent_template_arguments_p [that calls this function]
24340 does. */
24350 {
24353 /* A member template of a dependent class is not necessarily
24354 type-dependent, but it is a dependent template argument because it
24355 will be a member of an unknown specialization to that template. */
24358 }
24360 {
24364 {
24367 }
24370 }
24373 else
24376 }
24378 /* Returns true if ARGS (a collection of template arguments) contains
24379 any types that require structural equality testing. */
24381 bool
24383 {
24393 {
24396 {
24402 {
24403 /* Look inside the argument pack. */
24406 }
24409 {
24422 }
24423 }
24424 }
24427 }
24429 /* Returns true if ARGS (a collection of template arguments) contains
24430 any dependent arguments. */
24432 bool
24434 {
24444 {
24449 }
24452 }
24454 /* Returns TRUE if the template TMPL is type-dependent. */
24456 bool
24458 {
24460 {
24465 }
24467 /* Template template parameters are dependent. */
24471 /* So are names that have not been looked up. */
24475 }
24477 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24479 bool
24481 {
24484 }
24486 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24487 are dependent. */
24489 bool
24491 {
24498 {
24520 {
24524 }
24528 {
24532 {
24537 }
24538 }
24539 }
24542 }
24544 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24545 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24546 no such TYPE can be found. Note that this function peers inside
24547 uninstantiated templates and therefore should be used only in
24548 extremely limited situations. ONLY_CURRENT_P restricts this
24549 peering to the currently open classes hierarchy (which is required
24550 when comparing types). */
24552 tree
24554 {
24555 tree scope;
24556 tree name;
24557 tree decl;
24559 tree pushed_scope;
24560 tree result;
24565 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24566 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24567 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24568 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24569 identifier of the TYPENAME_TYPE anymore.
24570 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24571 TYPENAME_TYPE instead, we avoid messing up with a possible
24572 typedef variant case. */
24575 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24576 it first before we can figure out what NAME refers to. */
24578 {
24580 /* Given a class template A with a dependent base with nested type C,
24581 typedef typename A::C::C C will land us here, as trying to resolve
24582 the initial A::C leads to the local C typedef, which leads back to
24583 A::C::C. So we break the recursion now. */
24585 else
24587 }
24588 /* If we don't know what SCOPE refers to, then we cannot resolve the
24589 TYPENAME_TYPE. */
24592 /* If this is a typedef, we don't want to look inside (c++/11987). */
24595 /* If SCOPE isn't the template itself, it will not have a valid
24596 TYPE_FIELDS list. */
24598 /* scope is either the template itself or a compatible instantiation
24599 like X<T>, so look up the name in the original template. */
24601 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24603 /* If scope has no fields, it can't be a current instantiation. Check this
24604 before currently_open_class to avoid infinite recursion (71515). */
24607 /* If the SCOPE is not the current instantiation, there's no reason
24608 to look inside it. */
24611 /* Enter the SCOPE so that name lookup will be resolved as if we
24612 were in the class definition. In particular, SCOPE will no
24613 longer be considered a dependent type. */
24615 /* Look up the declaration. */
24617 tf_warning_or_error);
24621 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24622 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24628 {
24632 }
24635 {
24636 /* Obtain the template and the arguments. */
24639 {
24640 /* We get here with a plain identifier because a previous tentative
24641 parse of the nested-name-specifier as part of a ptr-operator saw
24642 ::template X<A>. The use of ::template is necessary in a
24643 ptr-operator, but wrong in a declarator-id.
24645 [temp.names]: In a qualified-id of a declarator-id, the keyword
24646 template shall not appear at the top level. */
24650 }
24652 /* Instantiate the template. */
24658 }
24660 /* Leave the SCOPE. */
24664 /* If we failed to resolve it, return the original typename. */
24668 /* If lookup found a typename type, resolve that too. */
24670 {
24671 /* Ill-formed programs can cause infinite recursion here, so we
24672 must catch that. */
24676 }
24678 /* Qualify the resulting type. */
24684 }
24686 /* EXPR is an expression which is not type-dependent. Return a proxy
24687 for EXPR that can be used to compute the types of larger
24688 expressions containing EXPR. */
24690 tree
24692 {
24693 tree inner_expr;
24695 /* When checking, try to get a constant value for all non-dependent
24696 expressions in order to expose bugs in *_dependent_expression_p
24697 and constexpr. This can affect code generation, see PR70704, so
24698 only do this for -fchecking=2. */
24701 /* Don't do this during nsdmi parsing as it can lead to
24702 unexpected recursive instantiations. */
24704 /* Don't do this during concept expansion either and for
24705 the same reason. */
24709 /* Preserve OVERLOADs; the functions must be available to resolve
24710 types. */
24721 /* There is no need to return a proxy for a variable. */
24724 /* Preserve string constants; conversions from string constants to
24725 "char *" are allowed, even though normally a "const char *"
24726 cannot be used to initialize a "char *". */
24729 /* Preserve void and arithmetic constants, as an optimization -- there is no
24730 reason to create a new node. */
24735 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
24736 There is at least one place where we want to know that a
24737 particular expression is a throw-expression: when checking a ?:
24738 expression, there are special rules if the second or third
24739 argument is a throw-expression. */
24743 /* Don't wrap an initializer list, we need to be able to look inside. */
24747 /* Don't wrap a dummy object, we need to be able to test for it. */
24766 /* If the type is unknown, it can't really be non-dependent */
24769 /* Otherwise, build a NON_DEPENDENT_EXPR. */
24771 }
24773 /* ARGS is a vector of expressions as arguments to a function call.
24774 Replace the arguments with equivalent non-dependent expressions.
24775 This modifies ARGS in place. */
24777 void
24779 {
24781 tree arg;
24784 {
24788 }
24789 }
24791 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
24792 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
24793 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
24795 static tree
24797 {
24811 }
24813 tree
24815 {
24817 }
24819 tree
24821 {
24823 }
24825 /* Return a C++17 deduction placeholder for class template TMPL. */
24827 tree
24829 {
24833 }
24835 /* True iff T is a C++17 class template deduction placeholder. */
24837 bool
24839 {
24841 }
24843 /* Make a "constrained auto" type-specifier. This is an
24844 auto type with constraints that must be associated after
24845 deduction. The constraint is formed from the given
24846 CONC and its optional sequence of arguments, which are
24847 non-null if written as partial-concept-id. */
24849 tree
24851 {
24854 /* Build the constraint. */
24862 /* Our canonical type depends on the constraint. */
24865 /* Attach the constraint to the type declaration. */
24868 }
24870 /* Given type ARG, return std::initializer_list<ARG>. */
24872 static tree
24874 {
24878 {
24882 "deducing from brace-enclosed initializer list"
24886 }
24892 }
24894 /* Replace auto in TYPE with std::initializer_list<auto>. */
24896 static tree
24898 {
24905 }
24907 /* Hash traits for hashing possibly constrained 'auto'
24908 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
24911 {
24914 };
24916 /* Hash the 'auto' T. */
24918 inline hashval_t
24920 {
24922 /* Matching constrained-type-specifiers denote the same template
24923 parameter, so hash the constraint. */
24925 else
24926 /* But unconstrained autos are all separate, so just hash the pointer. */
24928 }
24930 /* Compare two 'auto's. */
24934 {
24941 /* Two unconstrained autos are distinct. */
24946 }
24948 /* for_each_template_parm callback for extract_autos: if t is a (possibly
24949 constrained) auto, add it to the vector. */
24951 static int
24953 {
24956 {
24957 /* All the autos were built with index 0; fix that up now. */
24961 /* If this is a repeated constrained-type-specifier, use the index we
24962 chose before. */
24964 else
24965 {
24966 /* Otherwise this is new, so use the current count. */
24969 }
24971 }
24973 /* Always keep walking. */
24975 }
24977 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
24978 says they can appear anywhere in the type. */
24980 static tree
24982 {
24991 {
24996 }
24999 }
25001 /* The stem for deduction guide names. */
25004 /* Return the name for a deduction guide for class template TMPL. */
25006 tree
25008 {
25019 }
25021 /* True if NAME is the name of a deduction guide. */
25023 bool
25025 {
25029 }
25031 /* True if FN is a deduction guide. */
25033 bool
25035 {
25040 }
25042 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25044 bool
25046 {
25053 }
25055 /* True if FN is a guide generated from a constructor template. */
25057 bool
25059 {
25064 {
25067 }
25069 }
25071 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25072 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25073 template parameter types. Note that the handling of template template
25074 parameters relies on current_template_parms being set appropriately for the
25075 new template. */
25077 static tree
25080 {
25083 tree newtype;
25086 {
25093 }
25094 else
25098 tree newdecl
25103 tree newidx;
25106 {
25116 {
25121 // First create a copy (ttargs) of tsubst_args with an
25122 // additional level for the template template parameter's own
25123 // template parameters (ttparms).
25124 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25132 // Substitute ttargs into ttparms to fix references to
25133 // other template parameters.
25135 complain);
25136 // Now substitute again with args based on tparms, to reduce
25137 // the level of the ttparms.
25140 complain);
25141 // Finally, tack the adjusted parms onto tparms.
25143 current_template_parms);
25145 }
25146 }
25147 else
25148 {
25150 tree newconst
25162 }
25165 }
25167 /* Returns a C++17 class deduction guide template based on the constructor
25168 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25169 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25171 static tree
25173 {
25177 location_t loc;
25180 {
25184 {
25187 }
25188 else
25198 }
25199 else
25200 {
25203 tree fn_tmpl
25213 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25214 fully specialized args for the enclosing class. Strip those off, as
25215 the deduction guide won't have those template parameters. */
25218 /* Discard the 'this' parameter. */
25226 {
25229 /* For a member template constructor, we need to flatten the two
25230 template parameter lists into one, and then adjust the function
25231 signature accordingly. This gets...complicated. */
25234 /* For a member template we should have two levels of parms/args, one
25235 for the class and one for the constructor. We stripped
25236 specialized args for further enclosing classes above. */
25240 /* Template args for translating references to the two-level template
25241 parameters into references to the one-level template parameters we
25242 are creating. */
25247 /* Template parms for the constructor template. */
25250 /* Template parms for the class template. */
25254 /* Template parms for the deduction guide start as a copy of the
25255 template parms for the class. We set current_template_parms for
25256 lookup_template_class_1. */
25262 /* Now we need to rewrite the constructor parms to append them to the
25263 class parms. */
25265 {
25280 }
25282 /* Now we have a final set of template parms to substitute into the
25283 function signature. */
25292 }
25294 }
25297 {
25298 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25302 }
25306 FUNCTION_DECL,
25323 }
25325 /* Deduce template arguments for the class template placeholder PTYPE for
25326 template TMPL based on the initializer INIT, and return the resulting
25327 type. */
25329 static tree
25331 tsubst_flags_t complain)
25332 {
25334 {
25335 /* We should have handled this in the caller. */
25341 }
25352 {
25355 {
25356 /* As an exception, the first phase in 16.3.1.7 (considering the
25357 initializer list as a single argument) is omitted if the
25358 initializer list consists of a single expression of type cv U,
25359 where U is a specialization of C or a class derived from a
25360 specialization of C. */
25371 }
25374 else
25376 }
25377 else
25388 /* Prune explicit deduction guides in copy-initialization context. */
25390 {
25396 {
25397 /* Found a nonconverting guide, prune the candidates. */
25404 }
25405 }
25410 {
25413 }
25417 // FIXME cache artificial deduction guides
25420 {
25425 else
25429 }
25433 /* If this is list-initialization and the class has a list constructor, first
25434 try deducing from the list as a single argument, as [over.match.list]. */
25438 {
25442 }
25444 {
25450 {
25451 /* That didn't work, now try treating the list as a sequence of
25452 arguments. */
25455 }
25456 }
25458 /* Maybe generate an implicit deduction guide. */
25460 {
25464 /* Generate a copy guide. */
25467 /* Generate a default guide. */
25471 {
25474 }
25475 }
25478 {
25480 " of %qT, as it has no non-explicit deduction guides or "
25483 }
25485 {
25489 }
25492 {
25496 }
25499 {
25509 }
25514 }
25516 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25517 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25519 tree
25521 {
25523 tf_warning_or_error,
25524 adc_unspecified);
25525 }
25527 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25528 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25529 The CONTEXT determines the context in which auto deduction is performed
25530 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25531 OUTER_TARGS are used during template argument deduction
25532 (context == adc_unify) to properly substitute the result, and is ignored
25533 in other contexts.
25535 For partial-concept-ids, extra args may be appended to the list of deduced
25536 template arguments prior to determining constraint satisfaction. */
25538 tree
25542 {
25543 tree targs;
25550 /* Defining a subset of type-dependent expressions that we can deduce
25551 from ahead of time isn't worth the trouble. */
25555 /* C++17 class template argument deduction. */
25559 /* Nothing we can do with this, even in deduction context. */
25562 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25563 with either a new invented type template parameter U or, if the
25564 initializer is a braced-init-list (8.5.4), with
25565 std::initializer_list<U>. */
25567 {
25572 else
25573 {
25575 {
25579 "for deduction to %<std::initializer_list%>, use copy-"
25581 }
25583 }
25584 }
25595 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25596 and initializer has array type, deduce cv-qualified array type. */
25598 complain);
25600 {
25609 {
25613 }
25614 }
25615 else
25616 {
25618 tree tparms;
25622 else
25623 {
25627 }
25634 {
25636 /* Try again at instantiation time. */
25640 /* If type is error_mark_node a diagnostic must have been
25641 emitted by now. Also, having a mention to '<type error>'
25642 in the diagnostic is not really useful to the user. */
25643 {
25647 else
25652 }
25654 }
25655 }
25657 /* Check any placeholder constraints against the deduced type. */
25660 {
25661 /* Use the deduced type to check the associated constraints. If we
25662 have a partial-concept-id, rebuild the argument list so that
25663 we check using the extra arguments. */
25667 {
25670 }
25671 else
25674 {
25676 {
25678 {
25696 }
25698 }
25700 }
25701 }
25707 }
25709 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
25710 result. */
25712 tree
25714 {
25716 {
25722 /* In an abbreviated function template we didn't know we were dealing
25723 with a function template when we saw the auto return type, so update
25724 it to have the correct level. */
25726 }
25728 }
25730 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
25731 'decltype(auto)' or a deduced class template. */
25733 bool
25735 {
25741 else
25743 }
25745 /* for_each_template_parm callback for type_uses_auto. */
25747 int
25749 {
25751 }
25753 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
25754 a use of `auto'. Returns NULL_TREE otherwise. */
25756 tree
25758 {
25762 {
25763 /* The Concepts TS allows multiple autos in one type-specifier; just
25764 return the first one we find, do_auto_deduction will collect all of
25765 them. */
25769 else
25771 }
25772 else
25774 }
25776 /* For a given template T, return the vector of typedefs referenced
25777 in T for which access check is needed at T instantiation time.
25778 T is either a FUNCTION_DECL or a RECORD_TYPE.
25779 Those typedefs were added to T by the function
25780 append_type_to_template_for_access_check. */
25784 {
25785 tree ti;
25796 {
25801 }
25804 }
25806 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
25807 tied to T. That list of typedefs will be access checked at
25808 T instantiation time.
25809 T is either a FUNCTION_DECL or a RECORD_TYPE.
25810 TYPE_DECL is a TYPE_DECL node representing a typedef.
25811 SCOPE is the scope through which TYPE_DECL is accessed.
25812 LOCATION is the location of the usage point of TYPE_DECL.
25814 This function is a subroutine of
25815 append_type_to_template_for_access_check. */
25817 static void
25819 tree type_decl,
25820 tree scope,
25821 location_t location)
25822 {
25823 qualified_typedef_usage_t typedef_usage;
25824 tree ti;
25831 && type_decl
25845 }
25847 /* Append TYPE_DECL to the template TEMPL.
25848 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
25849 At TEMPL instanciation time, TYPE_DECL will be checked to see
25850 if it can be accessed through SCOPE.
25851 LOCATION is the location of the usage point of TYPE_DECL.
25853 e.g. consider the following code snippet:
25855 class C
25856 {
25857 typedef int myint;
25858 };
25860 template<class U> struct S
25861 {
25862 C::myint mi; // <-- usage point of the typedef C::myint
25863 };
25865 S<char> s;
25867 At S<char> instantiation time, we need to check the access of C::myint
25868 In other words, we need to check the access of the myint typedef through
25869 the C scope. For that purpose, this function will add the myint typedef
25870 and the scope C through which its being accessed to a list of typedefs
25871 tied to the template S. That list will be walked at template instantiation
25872 time and access check performed on each typedefs it contains.
25873 Note that this particular code snippet should yield an error because
25874 myint is private to C. */
25876 void
25878 tree type_decl,
25879 tree scope,
25880 location_t location)
25881 {
25887 /* Make sure we don't append the type to the template twice. */
25894 }
25896 /* Convert the generic type parameters in PARM that match the types given in the
25897 range [START_IDX, END_IDX) from the current_template_parms into generic type
25898 packs. */
25900 tree
25902 {
25913 {
25914 /* Create a distinct parameter pack type from the current parm and add it
25915 to the replacement args to tsubst below into the generic function
25916 parameter. */
25931 }
25937 /* If there are more levels then build up the replacement with the outer
25938 template parms. */
25942 replacement);
25945 }
25947 /* Entries in the decl_constraint hash table. */
25949 {
25950 tree decl;
25951 tree ci;
25952 };
25954 /* Hashing function and equality for constraint entries. */
25956 {
25958 {
25960 }
25963 {
25965 }
25966 };
25968 /* A mapping from declarations to constraint information. Note that
25969 both templates and their underlying declarations are mapped to the
25970 same constraint information.
25972 FIXME: This is defined in pt.c because garbage collection
25973 code is not being generated for constraint.cc. */
25977 /* Returns the template constraints of declaration T. If T is not
25978 constrained, return NULL_TREE. Note that T must be non-null. */
25980 tree
25982 {
25993 else
25995 }
25997 /* Associate the given constraint information CI with the declaration
25998 T. If T is a template, then the constraints are associated with
25999 its underlying declaration. Don't build associations if CI is
26000 NULL_TREE. */
26002 void
26004 {
26016 }
26018 /* Remove the associated constraints of the declaration T. */
26020 void
26022 {
26031 }
26033 /* Memoized satisfaction results for declarations. This
26034 maps the pair (constraint_info, arguments) to the result computed
26035 by constraints_satisfied_p. */
26038 {
26039 tree ci;
26040 tree args;
26041 tree result;
26042 };
26044 /* Hashing function and equality for constraint entries. */
26047 {
26049 {
26052 }
26055 {
26057 }
26058 };
26060 /* Memoized satisfaction results for concept checks. */
26063 {
26064 tree tmpl;
26065 tree args;
26066 tree result;
26067 };
26069 /* Hashing function and equality for constraint entries. */
26072 {
26074 {
26076 }
26079 {
26084 }
26085 };
26090 /* Search for a memoized satisfaction result. Returns one of the
26091 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26093 tree
26095 {
26100 else
26102 }
26104 /* Memoize the result of a satisfication test. Returns the saved result. */
26106 tree
26108 {
26115 }
26117 /* Search for a memoized satisfaction result for a concept. */
26119 tree
26121 {
26126 else
26128 }
26130 /* Memoize the result of a concept check. Returns the saved result. */
26132 tree
26134 {
26141 }
26145 /* Returns a prior concept specialization. This returns the substituted
26146 and normalized constraints defined by the concept. */
26148 tree
26150 {
26155 else
26157 }
26159 /* Save a concept expansion for later. */
26161 tree
26163 {
26170 }
26172 static hashval_t
26174 {
26183 }
26185 /* Compare the constraints of two subsumption entries. The LEFT1 and
26186 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26187 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26189 static bool
26191 {
26199 }
26201 /* Key/value pair for learning and memoizing subsumption results. This
26202 associates a pair of check constraints (including arguments) with
26203 a boolean value indicating the result. */
26206 {
26207 tree t1;
26208 tree t2;
26210 };
26212 /* Hashing function and equality for constraint entries. */
26215 {
26217 {
26219 }
26222 {
26227 }
26228 };
26232 /* Search for a previously cached subsumption result. */
26236 {
26241 else
26243 }
26245 /* Save a subsumption result. */
26247 bool
26249 {
26256 }
26258 /* Set up the hash table for constraint association. */
26260 void
26262 {
26271 }
26273 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26274 0..N-1. */
26276 void
26278 {
26281 integer_type_node,
26282 NULL_TREE),
26286 }
26288 /* Set up the hash tables for template instantiations. */
26290 void
26292 {
26298 }
26300 /* Print stats about the template hash tables for -fstats. */
26302 void
26304 {
26313 }