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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2016 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
44 /* The type of functions taking a tree, and some additional data, and
45 returning an int. */
48 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
49 instantiations have been deferred, either because their definitions
50 were not yet available, or because we were putting off doing the work. */
54 };
69 /* Live only within one (recursive) call to tsubst_expr. We use
70 this to pass the statement expression node from the STMT_EXPR
71 to the EXPR_STMT that is its result. */
74 // -------------------------------------------------------------------------- //
75 // Local Specialization Stack
76 //
77 // Implementation of the RAII helper for creating new local
78 // specializations.
81 {
83 }
86 {
89 }
91 /* True if we've recursed into fn_type_unification too many times. */
95 {
96 tree tmpl;
97 tree args;
98 tree spec;
99 };
102 {
105 };
111 /* Contains canonical template parameter types. The vector is indexed by
112 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
113 TREE_LIST, whose TREE_VALUEs contain the canonical template
114 parameters of various types and levels. */
117 #define UNIFY_ALLOW_NONE 0
118 #define UNIFY_ALLOW_MORE_CV_QUAL 1
119 #define UNIFY_ALLOW_LESS_CV_QUAL 2
120 #define UNIFY_ALLOW_DERIVED 4
121 #define UNIFY_ALLOW_INTEGER 8
122 #define UNIFY_ALLOW_OUTER_LEVEL 16
123 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
124 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
127 tbr_incomplete_type,
128 tbr_ambiguous_baseclass,
129 tbr_success
130 };
153 tree);
211 location_t);
218 /* Make the current scope suitable for access checking when we are
219 processing T. T can be FUNCTION_DECL for instantiated function
220 template, VAR_DECL for static member variable, or TYPE_DECL for
221 alias template (needed by instantiate_decl). */
223 static void
225 {
233 else
237 {
238 saved_access_scope = tree_cons
241 }
242 }
244 /* Restore the scope set up by push_access_scope. T is the node we
245 are processing. */
247 static void
249 {
251 {
254 }
258 else
260 }
262 /* Do any processing required when DECL (a member template
263 declaration) is finished. Returns the TEMPLATE_DECL corresponding
264 to DECL, unless it is a specialization, in which case the DECL
265 itself is returned. */
267 tree
269 {
276 {
277 tree type;
285 {
289 }
291 }
295 {
297 {
300 }
301 else
303 }
304 else
308 }
310 /* Create a template info node. */
312 tree
314 {
319 }
321 /* Return the template info node corresponding to T, whatever T is. */
323 tree
325 {
346 }
348 /* Returns the template nesting level of the indicated class TYPE.
350 For example, in:
351 template <class T>
352 struct A
353 {
354 template <class U>
355 struct B {};
356 };
358 A<T>::B<U> has depth two, while A<T> has depth one.
359 Both A<T>::B<int> and A<int>::B<U> have depth one, if
360 they are instantiations, not specializations.
362 This function is guaranteed to return 0 if passed NULL_TREE so
363 that, for example, `template_class_depth (current_class_type)' is
364 always safe. */
366 int
368 {
375 {
381 }
384 }
386 /* Subroutine of maybe_begin_member_template_processing.
387 Returns true if processing DECL needs us to push template parms. */
389 static bool
391 {
397 }
399 /* Subroutine of maybe_begin_member_template_processing.
400 Push the template parms in PARMS, starting from LEVELS steps into the
401 chain, and ending at the beginning, since template parms are listed
402 innermost first. */
404 static void
406 {
414 current_template_parms
420 NULL);
422 {
431 {
438 /* Push the CONST_DECL. */
444 }
445 }
446 }
448 /* Restore the template parameter context for a member template, a
449 friend template defined in a class definition, or a non-template
450 member of template class. */
452 void
454 {
455 tree parms;
460 {
463 /* Disregard full specializations (c++/60999). */
466 }
469 {
474 {
477 }
480 }
482 /* Remember how many levels of template parameters we pushed so that
483 we can pop them later. */
485 }
487 /* Undo the effects of maybe_begin_member_template_processing. */
489 void
491 {
500 {
504 }
505 }
507 /* Return a new template argument vector which contains all of ARGS,
508 but has as its innermost set of arguments the EXTRA_ARGS. */
510 static tree
512 {
513 tree new_args;
531 }
533 /* Like add_to_template_args, but only the outermost ARGS are added to
534 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
535 (EXTRA_ARGS) levels are added. This function is used to combine
536 the template arguments from a partial instantiation with the
537 template arguments used to attain the full instantiation from the
538 partial instantiation. */
540 static tree
542 {
543 tree new_args;
545 /* If there are more levels of EXTRA_ARGS than there are ARGS,
546 something very fishy is going on. */
549 /* If *all* the new arguments will be the EXTRA_ARGS, just return
550 them. */
554 /* For the moment, we make ARGS look like it contains fewer levels. */
559 /* Now, we restore ARGS to its full dimensions. */
563 }
565 /* Return the N levels of innermost template arguments from the ARGS. */
567 tree
569 {
570 tree new_args;
576 /* If N is 1, just return the innermost set of template arguments. */
580 /* If we're not removing anything, just return the arguments we were
581 given. */
587 /* Make a new set of arguments, not containing the outer arguments. */
594 }
596 /* The inverse of get_innermost_template_args: Return all but the innermost
597 EXTRA_LEVELS levels of template arguments from the ARGS. */
599 static tree
601 {
602 tree new_args;
608 /* If N is 1, just return the outermost set of template arguments. */
612 /* If we're not removing anything, just return the arguments we were
613 given. */
618 /* Make a new set of arguments, not containing the inner arguments. */
625 }
627 /* We've got a template header coming up; push to a new level for storing
628 the parms. */
630 void
632 {
633 /* We use a non-tag-transparent scope here, which causes pushtag to
634 put tags in this scope, rather than in the enclosing class or
635 namespace scope. This is the right thing, since we want
636 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
637 global template class, push_template_decl handles putting the
638 TEMPLATE_DECL into top-level scope. For a nested template class,
639 e.g.:
641 template <class T> struct S1 {
642 template <class T> struct S2 {};
643 };
645 pushtag contains special code to call pushdecl_with_scope on the
646 TEMPLATE_DECL for S2. */
652 /* Add a dummy parameter level while we process the parameter list. */
653 current_template_parms
656 current_template_parms);
657 }
659 /* This routine is called when a specialization is declared. If it is
660 invalid to declare a specialization here, an error is reported and
661 false is returned, otherwise this routine will return true. */
663 static bool
665 {
668 /* [temp.expl.spec]
670 An explicit specialization shall be declared in the namespace of
671 which the template is a member, or, for member templates, in the
672 namespace of which the enclosing class or enclosing class
673 template is a member. An explicit specialization of a member
674 function, member class or static data member of a class template
675 shall be declared in the namespace of which the class template
676 is a member. */
678 {
681 }
683 /* [temp.expl.spec]
685 In an explicit specialization declaration for a member of a class
686 template or a member template that appears in namespace scope,
687 the member template and some of its enclosing class templates may
688 remain unspecialized, except that the declaration shall not
689 explicitly specialize a class member template if its enclosing
690 class templates are not explicitly specialized as well. */
692 {
695 }
698 }
700 /* We've just seen template <>. */
702 bool
704 {
708 }
710 /* Called at then end of processing a declaration preceded by
711 template<>. */
713 void
715 {
718 }
720 /* Any template <>'s that we have seen thus far are not referring to a
721 function specialization. */
723 void
725 {
728 }
730 /* We've just seen a template header. If SPECIALIZATION is nonzero,
731 it was of the form template <>. */
733 static void
735 {
737 template_header_count++;
738 }
740 /* We're beginning an explicit instantiation. */
742 void
744 {
747 }
750 void
752 {
755 }
757 /* An explicit specialization or partial specialization of TMPL is being
758 declared. Check that the namespace in which the specialization is
759 occurring is permissible. Returns false iff it is invalid to
760 specialize TMPL in the current namespace. */
762 static bool
764 {
767 /* [tmpl.expl.spec]
769 An explicit specialization shall be declared in the namespace of
770 which the template is a member, or, for member templates, in the
771 namespace of which the enclosing class or enclosing class
772 template is a member. An explicit specialization of a member
773 function, member class or static data member of a class template
774 shall be declared in the namespace of which the class template is
775 a member. */
778 {
781 }
783 /* Same or super-using namespace. */
785 else
786 {
792 }
793 }
795 /* SPEC is an explicit instantiation. Check that it is valid to
796 perform this explicit instantiation in the current namespace. */
798 static void
800 {
801 tree ns;
803 /* DR 275: An explicit instantiation shall appear in an enclosing
804 namespace of its template. */
810 }
812 // Returns the type of a template specialization only if that
813 // specialization needs to be defined. Otherwise (e.g., if the type has
814 // already been defined), the function returns NULL_TREE.
815 static tree
817 {
818 // An implicit instantiation of an incomplete type implies
819 // the definition of a new class template.
820 //
821 // template<typename T>
822 // struct S;
823 //
824 // template<typename T>
825 // struct S<T*>;
826 //
827 // Here, S<T*> is an implicit instantiation of S whose type
828 // is incomplete.
832 // It can also be the case that TYPE is a completed specialization.
833 // Continuing the previous example, suppose we also declare:
834 //
835 // template<typename T>
836 // requires Integral<T>
837 // struct S<T*>;
838 //
839 // Here, S<T*> refers to the specialization S<T*> defined
840 // above. However, we need to differentiate definitions because
841 // we intend to define a new partial specialization. In this case,
842 // we rely on the fact that the constraints are different for
843 // this declaration than that above.
844 //
845 // Note that we also get here for injected class names and
846 // late-parsed template definitions. We must ensure that we
847 // do not create new type declarations for those cases.
849 {
853 // If there are no template parameters, this cannot be a new
854 // partial template specializtion?
858 // The injected-class-name is not a new partial specialization.
862 // If the constraints are not the same as those of the primary
863 // then, we can probably create a new specialization.
867 {
871 }
873 // Also, if there's a pre-existing specialization with matching
874 // constraints, then this also isn't new.
877 {
885 }
887 // Create a new type node (and corresponding type decl)
888 // for the newly declared specialization.
894 /* We only need a separate type node for storing the definition of this
895 partial specialization; uses of S<T*> are unconstrained, so all are
896 equivalent. So keep TYPE_CANONICAL the same. */
899 // Build the corresponding type decl.
905 }
908 }
910 /* The TYPE is being declared. If it is a template type, that means it
911 is a partial specialization. Do appropriate error-checking. */
913 tree
915 {
916 tree context;
921 /* A lambda that appears in specialization context is not itself a
922 specialization. */
927 {
931 }
936 {
941 else
944 }
946 {
947 /* This is for ordinary explicit specialization and partial
948 specialization of a template class such as:
950 template <> class C<int>;
952 or:
954 template <class T> class C<T*>;
956 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
959 {
966 {
971 }
972 }
978 /* Trying to define a specialization either without a template<> header
979 or in an inappropriate place. We've already given an error, so just
980 bail now so we don't actually define the specialization. */
982 }
988 {
989 /* This is for an explicit specialization of member class
990 template according to [temp.expl.spec/18]:
992 template <> template <class U> class C<int>::D;
994 The context `C<int>' must be an implicit instantiation.
995 Otherwise this is just a member class template declared
996 earlier like:
998 template <> class C<int> { template <class U> class D; };
999 template <> template <class U> class C<int>::D;
1001 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1002 while in the second case, `C<int>::D' is a primary template
1003 and `C<T>::D' may not exist. */
1007 {
1008 tree t;
1013 {
1018 }
1020 /* Check for invalid specialization after instantiation:
1022 template <> template <> class C<int>::D<int>;
1023 template <> template <class U> class C<int>::D; */
1027 {
1031 {
1032 /* We already have a full specialization of this partial
1033 instantiation, or a full specialization has been
1034 looked up but not instantiated. Reassign it to the
1035 new member specialization template. */
1036 spec_entry elt;
1048 spec_entry **slot
1053 }
1054 else
1055 /* But if we've had an implicit instantiation, that's a
1056 problem ([temp.expl.spec]/6). */
1059 }
1061 /* Mark TYPE as a specialization. And as a result, we only
1062 have one level of template argument for the innermost
1063 class template. */
1068 }
1069 }
1071 {
1072 /* Someday C++0x may allow for enum template specialization. */
1077 else
1078 {
1081 }
1082 }
1085 }
1087 /* Returns nonzero if we can optimize the retrieval of specializations
1088 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1089 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1093 {
1096 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1097 parameter. */
1099 /* The optimized lookup depends on the fact that the
1100 template arguments for the member function template apply
1101 purely to the containing class, which is not true if the
1102 containing class is an explicit or partial
1103 specialization. */
1107 /* It is possible to have a template that is not a member
1108 template and is not a member of a template class:
1110 template <typename T>
1111 struct S { friend A::f(); };
1113 Here, the friend function is a template, but the context does
1114 not have template information. The optimized lookup relies
1115 on having ARGS be the template arguments for both the class
1116 and the function template. */
1118 }
1120 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1121 gone through coerce_template_parms by now. */
1123 static void
1125 {
1128 {
1131 {
1138 /* Allow typedefs on the type of a non-type argument, since a
1140 else
1142 }
1143 }
1145 }
1147 /* Retrieve the specialization (in the sense of [temp.spec] - a
1148 specialization is either an instantiation or an explicit
1149 specialization) of TMPL for the given template ARGS. If there is
1150 no such specialization, return NULL_TREE. The ARGS are a vector of
1151 arguments, or a vector of vectors of arguments, in the case of
1152 templates with more than one level of parameters.
1154 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1155 then we search for a partial specialization matching ARGS. This
1156 parameter is ignored if TMPL is not a class template.
1158 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1159 result is a NONTYPE_ARGUMENT_PACK. */
1161 static tree
1163 {
1173 /* There should be as many levels of arguments as there are
1174 levels of parameters. */
1184 {
1185 tree class_template;
1186 tree class_specialization;
1188 tree fns;
1191 /* The template arguments actually apply to the containing
1192 class. Find the class specialization with those
1193 arguments. */
1195 class_specialization
1199 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1200 for the specialization. */
1204 /* Iterate through the methods with the indicated name, looking
1205 for the one that has an instance of TMPL. */
1208 {
1211 /* using-declarations can add base methods to the method vec,
1212 and we don't want those here. */
1215 }
1217 }
1218 else
1219 {
1221 spec_entry elt;
1230 else
1238 }
1241 }
1243 /* Like retrieve_specialization, but for local declarations. */
1245 tree
1247 {
1253 }
1255 /* Returns nonzero iff DECL is a specialization of TMPL. */
1257 int
1259 {
1260 tree t;
1263 {
1269 }
1270 else
1271 {
1280 }
1283 }
1285 /* Returns nonzero iff DECL is a specialization of friend declaration
1286 FRIEND_DECL according to [temp.friend]. */
1288 bool
1290 {
1297 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1298 of a template class, we want to check if DECL is a specialization
1299 if this. */
1303 {
1304 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1307 }
1312 /* There is nothing to do if this is not a template friend. */
1319 /* [temp.friend/6]
1320 A member of a class template may be declared to be a friend of a
1321 non-template class. In this case, the corresponding member of
1322 every specialization of the class template is a friend of the
1323 class granting friendship.
1325 For example, given a template friend declaration
1327 template <class T> friend void A<T>::f();
1329 the member function below is considered a friend
1331 template <> struct A<int> {
1332 void f();
1333 };
1335 For this type of template friend, TEMPLATE_DEPTH below will be
1336 nonzero. To determine if DECL is a friend of FRIEND, we first
1337 check if the enclosing class is a specialization of another. */
1344 {
1345 /* Next, we check the members themselves. In order to handle
1346 a few tricky cases, such as when FRIEND_DECL's are
1348 template <class T> friend void A<T>::g(T t);
1349 template <class T> template <T t> friend void A<T>::h();
1351 and DECL's are
1353 void A<int>::g(int);
1354 template <int> void A<int>::h();
1356 we need to figure out ARGS, the template arguments from
1357 the context of DECL. This is required for template substitution
1358 of `T' in the function parameter of `g' and template parameter
1359 of `h' in the above examples. Here ARGS corresponds to `int'. */
1366 {
1368 {
1371 else
1373 current_depth++;
1374 }
1376 }
1379 {
1381 tree friend_type;
1382 tree decl_type;
1383 tree friend_args_type;
1384 tree decl_args_type;
1386 /* Make sure that both DECL and FRIEND_DECL are templates or
1387 non-templates. */
1393 {
1394 /* If both are templates, check template parameter list. */
1395 tree friend_parms
1400 friend_parms))
1404 }
1405 else
1413 /* Check if return types match. */
1417 /* Check if function parameter types match, ignoring the
1418 `this' parameter. */
1427 }
1428 else
1429 {
1430 /* DECL is a TYPE_DECL */
1434 /* Make sure that both DECL and FRIEND_DECL are templates or
1435 non-templates. */
1436 is_template
1443 {
1444 tree friend_parms;
1445 /* If both are templates, check the name of the two
1446 TEMPLATE_DECL's first because is_friend didn't. */
1451 /* Now check template parameter list. */
1452 friend_parms
1455 return comp_template_parms
1457 friend_parms);
1458 }
1459 else
1462 }
1463 }
1465 }
1467 /* Register the specialization SPEC as a specialization of TMPL with
1468 the indicated ARGS. IS_FRIEND indicates whether the specialization
1469 is actually just a friend declaration. Returns SPEC, or an
1470 equivalent prior declaration, if available.
1472 We also store instantiations of field packs in the hash table, even
1473 though they are not themselves templates, to make lookup easier. */
1475 static tree
1477 hashval_t hash)
1478 {
1479 tree fn;
1481 spec_entry elt;
1489 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1490 register it; we want the corresponding TEMPLATE_DECL instead.
1491 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1492 the more obvious `uses_template_parms (spec)' to avoid problems
1493 with default function arguments. In particular, given
1494 something like this:
1496 template <class T> void f(T t1, T t = T())
1498 the default argument expression is not substituted for in an
1499 instantiation unless and until it is actually needed. */
1503 /* We don't put these specializations in the hash table, but we might
1504 want to give an error about a mismatch. */
1506 else
1507 {
1515 slot =
1519 else
1521 }
1523 /* We can sometimes try to re-register a specialization that we've
1524 already got. In particular, regenerate_decl_from_template calls
1525 duplicate_decls which will update the specialization list. But,
1526 we'll still get called again here anyhow. It's more convenient
1527 to simply allow this than to try to prevent it. */
1531 {
1533 {
1536 {
1538 fn);
1540 }
1541 else
1542 {
1543 tree clone;
1544 /* This situation should occur only if the first
1545 specialization is an implicit instantiation, the
1546 second is an explicit specialization, and the
1547 implicit instantiation has not yet been used. That
1548 situation can occur if we have implicitly
1549 instantiated a member function and then specialized
1550 it later.
1552 We can also wind up here if a friend declaration that
1553 looked like an instantiation turns out to be a
1554 specialization:
1556 template <class T> void foo(T);
1557 class S { friend void foo<>(int) };
1558 template <> void foo(int);
1560 We transform the existing DECL in place so that any
1561 pointers to it become pointers to the updated
1562 declaration.
1564 If there was a definition for the template, but not
1565 for the specialization, we want this to look as if
1566 there were no definition, and vice versa. */
1569 /* The call to duplicate_decls will have applied
1570 [temp.expl.spec]:
1572 An explicit specialization of a function template
1573 is inline only if it is explicitly declared to be,
1574 and independently of whether its function template
1575 is.
1577 to the primary function; now copy the inline bits to
1578 the various clones. */
1580 {
1587 }
1591 }
1592 }
1594 {
1596 /* Dup decl failed, but this is a new definition. Set the
1597 line number so any errors match this new
1598 definition. */
1602 }
1603 }
1607 /* A specialization must be declared in the same namespace as the
1608 template it is specializing. */
1614 {
1623 /* If TMPL is a forward declaration of a template function, keep a list
1624 of all specializations in case we need to reassign them to a friend
1625 template later in tsubst_friend_function.
1627 Also keep a list of all variable template instantiations so that
1628 process_partial_specialization can check whether a later partial
1629 specialization would have used it. */
1632 }
1635 }
1637 /* Returns true iff two spec_entry nodes are equivalent. */
1641 bool
1643 {
1650 /* tmpl could be a FIELD_DECL for a capture pack. */
1654 {
1655 /* Partial specializations of a variable template can be distinguished by
1656 constraints. */
1660 }
1664 }
1666 /* Returns a hash for a template TMPL and template arguments ARGS. */
1668 static hashval_t
1670 {
1673 }
1675 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1676 ignoring SPEC. */
1678 hashval_t
1680 {
1682 }
1684 /* Recursively calculate a hash value for a template argument ARG, for use
1685 in the hash tables of template specializations. */
1687 hashval_t
1689 {
1701 /* We can get one of these when re-hashing a previous entry in the middle
1702 of substituting into a pack expansion. Just look through it. */
1711 {
1719 {
1724 }
1746 {
1750 {
1753 }
1755 }
1759 {
1762 }
1773 val = iterative_hash_template_arg
1785 val);
1787 val);
1796 /* A lambda can't appear in a template arg, but don't crash on
1797 erroneous input. */
1809 /* Now hash operands as usual. */
1814 }
1817 {
1820 {
1821 // We want an alias specialization that survived strip_typedefs
1822 // to hash differently from its TYPE_CANONICAL, to avoid hash
1823 // collisions that compare as different in template_args_equal.
1824 // These could be dependent specializations that strip_typedefs
1825 // left alone, or untouched specializations because
1826 // coerce_template_parms returns the unconverted template
1827 // arguments if it sees incomplete argument packs.
1830 }
1833 val);
1836 /* Otherwise just compare the types during lookup. */
1845 {
1850 }
1851 }
1854 }
1856 /* Unregister the specialization SPEC as a specialization of TMPL.
1857 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1858 if the SPEC was listed as a specialization of TMPL.
1860 Note that SPEC has been ggc_freed, so we can't look inside it. */
1862 bool
1864 {
1866 spec_entry elt;
1874 {
1879 }
1882 }
1884 /* Like register_specialization, but for local declarations. We are
1885 registering SPEC, an instantiation of TMPL. */
1887 void
1889 {
1891 }
1893 /* TYPE is a class type. Returns true if TYPE is an explicitly
1894 specialized class. */
1896 bool
1898 {
1902 }
1904 /* Print the list of functions at FNS, going through all the overloads
1905 for each element of the list. Alternatively, FNS can not be a
1906 TREE_LIST, in which case it will be printed together with all the
1907 overloads.
1909 MORE and *STR should respectively be FALSE and NULL when the function
1910 is called from the outside. They are used internally on recursive
1911 calls. print_candidates manages the two parameters and leaves NULL
1912 in *STR when it ends. */
1914 static void
1916 {
1922 {
1926 }
1927 else
1928 {
1931 {
1932 /* Pick the prefix string. */
1934 {
1938 }
1942 }
1945 }
1948 {
1951 }
1952 }
1954 /* Print the list of candidate FNS in an error message. FNS can also
1955 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1957 void
1959 {
1963 }
1965 /* Get a (possibly) constrained template declaration for the
1966 purpose of ordering candidates. */
1967 static tree
1969 {
1975 }
1977 /* Among candidates having the same signature, return the
1978 most constrained or NULL_TREE if there is no best candidate.
1979 If the signatures of candidates vary (e.g., template
1980 specialization vs. member function), then there can be no
1981 most constrained.
1983 Note that we don't compare constraints on the functions
1984 themselves, but rather those of their templates. */
1985 static tree
1987 {
1988 // Try to find the best candidate in a first pass.
1991 {
1998 }
2000 // Verify that the champ is better than previous candidates.
2005 }
2008 }
2011 /* Returns the template (one of the functions given by TEMPLATE_ID)
2012 which can be specialized to match the indicated DECL with the
2013 explicit template args given in TEMPLATE_ID. The DECL may be
2014 NULL_TREE if none is available. In that case, the functions in
2015 TEMPLATE_ID are non-members.
2017 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2018 specialization of a member template.
2020 The TEMPLATE_COUNT is the number of references to qualifying
2021 template classes that appeared in the name of the function. See
2022 check_explicit_specialization for a more accurate description.
2024 TSK indicates what kind of template declaration (if any) is being
2025 declared. TSK_TEMPLATE indicates that the declaration given by
2026 DECL, though a FUNCTION_DECL, has template parameters, and is
2027 therefore a template function.
2029 The template args (those explicitly specified and those deduced)
2030 are output in a newly created vector *TARGS_OUT.
2032 If it is impossible to determine the result, an error message is
2033 issued. The error_mark_node is returned to indicate failure. */
2035 static tree
2037 tree decl,
2041 tmpl_spec_kind tsk)
2042 {
2043 tree fns;
2044 tree targs;
2045 tree explicit_targs;
2048 /* A TREE_LIST of templates of which DECL may be a specialization.
2049 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2050 corresponding TREE_PURPOSE is the set of template arguments that,
2051 when used to instantiate the template, would produce a function
2052 with the signature of DECL. */
2062 /* We shouldn't be specializing a member template of an
2063 unspecialized class template; we already gave an error in
2064 check_specialization_scope, now avoid crashing. */
2067 {
2070 }
2078 /* Check for baselinks. */
2083 {
2086 }
2088 {
2091 }
2093 /* Count the number of template headers specified for this
2094 specialization. */
2104 {
2107 tf_warning_or_error,
2111 }
2113 {
2117 {
2118 tree decl_arg_types;
2119 tree fn_arg_types;
2120 tree insttype;
2122 /* In case of explicit specialization, we need to check if
2123 the number of template headers appearing in the specialization
2124 is correct. This is usually done in check_explicit_specialization,
2125 but the check done there cannot be exhaustive when specializing
2126 member functions. Consider the following code:
2128 template <> void A<int>::f(int);
2129 template <> template <> void A<int>::f(int);
2131 Assuming that A<int> is not itself an explicit specialization
2132 already, the first line specializes "f" which is a non-template
2133 member function, whilst the second line specializes "f" which
2134 is a template member function. So both lines are syntactically
2135 correct, and check_explicit_specialization does not reject
2136 them.
2138 Here, we can do better, as we are matching the specialization
2139 against the declarations. We count the number of template
2140 headers, and we check if they match TEMPLATE_COUNT + 1
2141 (TEMPLATE_COUNT is the number of qualifying template classes,
2142 plus there must be another header for the member template
2143 itself).
2145 Notice that if header_count is zero, this is not a
2146 specialization but rather a template instantiation, so there
2147 is no check we can perform here. */
2151 /* Check that the number of template arguments at the
2152 innermost level for DECL is the same as for FN. */
2160 /* DECL might be a specialization of FN. */
2164 /* For a non-static member function, we need to make sure
2165 that the const qualification is the same. Since
2166 get_bindings does not try to merge the "this" parameter,
2167 we must do the comparison explicitly. */
2173 /* Skip the "this" parameter and, for constructors of
2174 classes with virtual bases, the VTT parameter. A
2175 full specialization of a constructor will have a VTT
2176 parameter, but a template never will. */
2177 decl_arg_types
2179 fn_arg_types
2182 /* Function templates cannot be specializations; there are
2183 no partial specializations of functions. Therefore, if
2184 the type of DECL does not match FN, there is no
2185 match.
2187 Note that it should never be the case that we have both
2188 candidates added here, and for regular member functions
2189 below. */
2191 {
2195 }
2197 /* See whether this function might be a specialization of this
2198 template. Suppress access control because we might be trying
2199 to make this specialization a friend, and we have already done
2200 access control for the declaration of the specialization. */
2206 /* We cannot deduce template arguments that when used to
2207 specialize TMPL will produce DECL. */
2210 /* Remove, from the set of candidates, all those functions
2211 whose constraints are not satisfied. */
2215 // Then, try to form the new function type.
2219 fn_arg_types
2224 /* Save this template, and the arguments deduced. */
2226 }
2228 /* FN is an ordinary member function, and we need a
2229 specialization of a member template. */
2230 ;
2232 /* We can get IDENTIFIER_NODEs here in certain erroneous
2233 cases. */
2234 ;
2236 /* This is just an ordinary non-member function. Nothing can
2237 be a specialization of that. */
2238 ;
2240 /* Cannot specialize functions that are created implicitly. */
2241 ;
2242 else
2243 {
2244 tree decl_arg_types;
2246 /* This is an ordinary member function. However, since
2247 we're here, we can assume its enclosing class is a
2248 template class. For example,
2250 template <typename T> struct S { void f(); };
2251 template <> void S<int>::f() {}
2253 Here, S<int>::f is a non-template, but S<int> is a
2254 template class. If FN has the same type as DECL, we
2255 might be in business. */
2258 /* Its enclosing class is an explicit specialization
2259 of a template class. This is not a candidate. */
2264 /* The return types differ. */
2267 /* Adjust the type of DECL in case FN is a static member. */
2274 decl_arg_types))
2277 // If the deduced arguments do not satisfy the constraints,
2278 // this is not a candidate.
2282 // Add the candidate.
2284 }
2285 }
2288 {
2289 /* We have:
2291 [temp.expl.spec]
2293 It is possible for a specialization with a given function
2294 signature to be instantiated from more than one function
2295 template. In such cases, explicit specification of the
2296 template arguments must be used to uniquely identify the
2297 function template specialization being specialized.
2299 Note that here, there's no suggestion that we're supposed to
2300 determine which of the candidate templates is most
2301 specialized. However, we, also have:
2303 [temp.func.order]
2305 Partial ordering of overloaded function template
2306 declarations is used in the following contexts to select
2307 the function template to which a function template
2308 specialization refers:
2310 -- when an explicit specialization refers to a function
2311 template.
2313 So, we do use the partial ordering rules, at least for now.
2314 This extension can only serve to make invalid programs valid,
2315 so it's safe. And, there is strong anecdotal evidence that
2316 the committee intended the partial ordering rules to apply;
2317 the EDG front end has that behavior, and John Spicer claims
2318 that the committee simply forgot to delete the wording in
2319 [temp.expl.spec]. */
2322 {
2325 }
2326 }
2328 // Concepts allows multiple declarations of member functions
2329 // with the same signature. Like above, we need to rely on
2330 // on the partial ordering of those candidates to determine which
2331 // is the best.
2333 {
2335 {
2338 }
2339 }
2342 {
2349 else
2352 }
2356 {
2362 }
2364 /* We have one, and exactly one, match. */
2366 {
2370 // Propagate the candidate's constraints to the declaration.
2373 /* DECL is a re-declaration or partial instantiation of a template
2374 function. */
2377 /* It was a specialization of an ordinary member function in a
2378 template class. */
2380 }
2382 /* It was a specialization of a template. */
2385 {
2390 }
2391 else
2394 }
2396 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2397 but with the default argument values filled in from those in the
2398 TMPL_TYPES. */
2400 static tree
2402 tree tmpl_types)
2403 {
2404 tree new_spec_types;
2412 /* Substitute into the rest of the list. */
2413 new_spec_types =
2417 /* Add the default argument for this parameter. */
2420 new_spec_types);
2421 }
2423 /* DECL is an explicit specialization. Replicate default arguments
2424 from the template it specializes. (That way, code like:
2426 template <class T> void f(T = 3);
2427 template <> void f(double);
2428 void g () { f (); }
2430 works, as required.) An alternative approach would be to look up
2431 the correct default arguments at the call-site, but this approach
2432 is consistent with how implicit instantiations are handled. */
2434 static void
2436 {
2437 tree tmpl;
2438 tree spec_types;
2439 tree tmpl_types;
2440 tree new_spec_types;
2441 tree old_type;
2442 tree new_type;
2443 tree t;
2448 /* See if there's anything we need to do. */
2461 {
2462 /* Remove the this pointer, but remember the object's type for
2463 CV quals. */
2469 {
2470 /* DECL may contain more parameters than TMPL due to the extra
2471 in-charge parameter in constructors and destructors. */
2474 }
2476 {
2479 }
2480 }
2482 /* Compute the merged default arguments. */
2483 new_spec_types =
2486 /* Compute the new FUNCTION_TYPE. */
2488 {
2492 new_spec_types);
2495 /* Put the in-charge parameter back. */
2498 new_spec_types);
2502 new_spec_types);
2503 }
2504 else
2506 new_spec_types);
2516 }
2518 /* Return the number of template headers we expect to see for a definition
2519 or specialization of CTYPE or one of its non-template members. */
2521 int
2523 {
2527 {
2528 /* You're supposed to have one `template <...>' for every
2529 template class, but you don't need one for a full
2530 specialization. For example:
2532 template <class T> struct S{};
2533 template <> struct S<int> { void f(); };
2534 void S<int>::f () {}
2536 is correct; there shouldn't be a `template <>' for the
2537 definition of `S<int>::f'. */
2539 /* If CTYPE does not have template information of any
2540 kind, then it is not a template, nor is it nested
2541 within a template. */
2549 }
2552 }
2554 /* Do a simple sanity check on the template headers that precede the
2555 variable declaration DECL. */
2557 void
2559 {
2564 {
2567 "variable templates only available with "
2570 // Namespace-scope variable templates should have a template header.
2572 }
2574 {
2581 "members of an explicitly specialized class are defined "
2583 }
2584 }
2586 /* Check to see if the function just declared, as indicated in
2587 DECLARATOR, and in DECL, is a specialization of a function
2588 template. We may also discover that the declaration is an explicit
2589 instantiation at this point.
2591 Returns DECL, or an equivalent declaration that should be used
2592 instead if all goes well. Issues an error message if something is
2593 amiss. Returns error_mark_node if the error is not easily
2594 recoverable.
2596 FLAGS is a bitmask consisting of the following flags:
2598 2: The function has a definition.
2599 4: The function is a friend.
2601 The TEMPLATE_COUNT is the number of references to qualifying
2602 template classes that appeared in the name of the function. For
2603 example, in
2605 template <class T> struct S { void f(); };
2606 void S<int>::f();
2608 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2609 classes are not counted in the TEMPLATE_COUNT, so that in
2611 template <class T> struct S {};
2612 template <> struct S<int> { void f(); }
2613 template <> void S<int>::f();
2615 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2616 invalid; there should be no template <>.)
2618 If the function is a specialization, it is marked as such via
2619 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2620 is set up correctly, and it is added to the list of specializations
2621 for that template. */
2623 tree
2625 tree decl,
2628 {
2637 tmpl_spec_kind tsk;
2640 {
2643 else
2645 }
2646 else
2650 {
2653 {
2656 }
2658 {
2660 /* This could be something like:
2662 template <class T> void f(T);
2663 class S { friend void f<>(int); } */
2665 else
2666 {
2667 /* This case handles bogus declarations like template <>
2668 template <class T> void f<int>(); */
2671 declarator);
2673 }
2674 }
2678 /* The error has already been reported in
2679 check_specialization_scope. */
2685 /* Fall through. */
2698 decl);
2701 else
2705 /* Fall through. */
2711 /* In cases like template<> constexpr bool v = true;
2712 We'll give an error in check_template_variable. */
2718 else
2724 {
2725 /* This case handles bogus declarations like template <>
2726 template <class T> void f<int>(); */
2730 declarator);
2732 {
2733 /* Partial specialization of variable template. */
2737 }
2741 else
2745 ok:;
2746 }
2749 /* This is a specialization of a member template, without
2750 specialization the containing class. Something like:
2752 template <class T> struct S {
2753 template <class U> void f (U);
2754 };
2755 template <> template <class U> void S<int>::f(U) {}
2757 That's a specialization -- but of the entire template. */
2763 }
2766 /* This doesn't apply to variable templates. */
2769 {
2773 {
2777 }
2778 }
2781 {
2786 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2788 {
2789 tree fns;
2794 else
2795 {
2796 /* If there is no class context, the explicit instantiation
2797 must be at namespace scope. */
2800 /* Find the namespace binding, using the declaration
2801 context. */
2805 {
2808 }
2809 }
2812 }
2818 {
2820 /* A specialization in class scope. This is invalid,
2821 but the error will already have been flagged by
2822 check_specialization_scope. */
2824 else
2825 {
2826 /* It's not valid to write an explicit instantiation in
2827 class scope, e.g.:
2829 class C { template void f(); }
2831 This case is caught by the parser. However, on
2832 something like:
2834 template class C { void f(); };
2836 (which is invalid) we can get here. The error will be
2837 issued later. */
2838 ;
2839 }
2842 }
2845 {
2846 // We'll match variable templates in start_decl.
2850 /* Find the list of functions in ctype that have the same
2851 name as the declared function. */
2857 {
2862 {
2863 /* From [temp.expl.spec]:
2865 If such an explicit specialization for the member
2866 of a class template names an implicitly-declared
2867 special member function (clause _special_), the
2868 program is ill-formed.
2870 Similar language is found in [temp.explicit]. */
2873 }
2876 }
2879 {
2883 }
2884 else
2885 {
2887 tree ovl;
2889 /* For a type-conversion operator, we cannot do a
2890 name-based lookup. We might be looking for `operator
2891 int' which will be a specialization of `operator T'.
2892 So, we find *all* the conversion operators, and then
2893 select from them. */
2901 {
2903 /* There are no more conversion functions. */
2906 /* Glue all these conversion functions together
2907 with those we already have. */
2910 }
2911 }
2914 {
2917 }
2918 else
2920 }
2922 /* Figure out what exactly is being specialized at this point.
2923 Note that for an explicit instantiation, even one for a
2924 member function, we cannot tell apriori whether the
2925 instantiation is for a member template, or just a member
2926 function of a template class. Even if a member template is
2927 being instantiated, the member template arguments may be
2928 elided if they can be deduced from the rest of the
2929 declaration. */
2932 member_specialization,
2933 template_count,
2934 tsk);
2937 /* We couldn't figure out what this declaration was
2938 specializing. */
2940 else
2941 {
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 /* Structure used to track the progress of find_parameter_packs_r. */
3388 struct find_parameter_pack_data
3389 {
3390 /* TREE_LIST that will contain all of the parameter packs found by
3391 the traversal. */
3394 /* Set of AST nodes that have been visited by the traversal. */
3397 /* True iff we're making a type pack expansion. */
3399 };
3401 /* Identifies all of the argument packs that occur in a template
3402 argument and appends them to the TREE_LIST inside DATA, which is a
3403 find_parameter_pack_data structure. This is a subroutine of
3404 make_pack_expansion and uses_parameter_packs. */
3405 static tree
3407 {
3413 /* Handle type aliases/typedefs. */
3415 {
3422 }
3424 /* Identify whether this is a parameter pack or not. */
3426 {
3435 /* If the placeholder appears in the decl-specifier-seq of a function
3436 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3437 is a pack expansion, the invented template parameter is a template
3438 parameter pack. */
3448 {
3449 /* We don't want to walk into the type of a PARM_DECL,
3450 because we don't want to see the type parameter pack. */
3453 }
3456 /* Look through a lambda capture proxy to the field pack. */
3459 {
3465 }
3467 {
3469 find_parameter_packs_r,
3472 }
3479 /* Not a parameter pack. */
3481 }
3484 {
3485 /* Add this parameter pack to the list. */
3487 }
3493 /* This switch statement will return immediately if we don't find a
3494 parameter pack. */
3496 {
3501 /* Check the template itself. */
3504 /* Check the template arguments. */
3520 /* Fall through. */
3561 {
3562 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3563 type_pack_expansion_p to false so that any placeholders
3564 within the expression don't get marked as parameter packs. */
3572 }
3576 }
3579 }
3581 /* Determines if the expression or type T uses any parameter packs. */
3582 bool
3584 {
3593 }
3595 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3596 representation a base-class initializer into a parameter pack
3597 expansion. If all goes well, the resulting node will be an
3598 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3599 respectively. */
3600 tree
3602 {
3603 tree result;
3612 {
3613 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3614 class initializer. In this case, the TREE_PURPOSE will be a
3615 _TYPE node (representing the base class expansion we're
3616 initializing) and the TREE_VALUE will be a TREE_LIST
3617 containing the initialization arguments.
3619 The resulting expansion looks somewhat different from most
3620 expansions. Rather than returning just one _EXPANSION, we
3621 return a TREE_LIST whose TREE_PURPOSE is a
3622 TYPE_PACK_EXPANSION containing the bases that will be
3623 initialized. The TREE_VALUE will be identical to the
3624 original TREE_VALUE, which is a list of arguments that will
3625 be passed to each base. We do not introduce any new pack
3626 expansion nodes into the TREE_VALUE (although it is possible
3627 that some already exist), because the TREE_PURPOSE and
3628 TREE_VALUE all need to be expanded together with the same
3629 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3630 resulting TREE_PURPOSE will mention the parameter packs in
3631 both the bases and the arguments to the bases. */
3632 tree purpose;
3633 tree value;
3636 /* Determine which parameter packs will be used by the base
3637 class expansion. */
3646 {
3650 }
3653 {
3654 /* Collect the sets of parameter packs used in each of the
3655 initialization arguments. */
3657 {
3658 /* Determine which parameter packs will be expanded in this
3659 argument. */
3662 }
3663 }
3667 /* Create the pack expansion type for the base type. */
3672 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3673 they will rarely be compared to anything. */
3677 }
3682 /* Build the PACK_EXPANSION_* node. */
3683 result = for_types
3688 {
3689 /* Propagate type and const-expression information. */
3692 }
3693 else
3694 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3695 they will rarely be compared to anything. */
3698 /* Determine which parameter packs will be expanded. */
3705 /* Make sure we found some parameter packs. */
3707 {
3710 else
3713 }
3719 }
3721 /* Checks T for any "bare" parameter packs, which have not yet been
3722 expanded, and issues an error if any are found. This operation can
3723 only be done on full expressions or types (e.g., an expression
3724 statement, "if" condition, etc.), because we could have expressions like:
3726 foo(f(g(h(args)))...)
3728 where "args" is a parameter pack. check_for_bare_parameter_packs
3729 should not be called for the subexpressions args, h(args),
3730 g(h(args)), or f(g(h(args))), because we would produce erroneous
3731 error messages.
3733 Returns TRUE and emits an error if there were bare parameter packs,
3734 returns FALSE otherwise. */
3735 bool
3737 {
3754 {
3757 {
3766 else
3771 else
3775 }
3778 }
3781 }
3783 /* Expand any parameter packs that occur in the template arguments in
3784 ARGS. */
3785 tree
3787 {
3793 /* First, determine if we need to expand anything, and the number of
3794 slots we'll need. */
3796 {
3801 {
3805 else
3807 }
3808 else
3809 {
3811 num_result_args++;
3812 }
3813 }
3815 /* If no expansion is necessary, we're done. */
3819 /* Expand arguments. */
3822 non_default_args_count =
3825 {
3828 {
3835 }
3836 else
3837 {
3840 }
3841 }
3845 }
3847 /* Checks if DECL shadows a template parameter.
3849 [temp.local]: A template-parameter shall not be redeclared within its
3850 scope (including nested scopes).
3852 Emits an error and returns TRUE if the DECL shadows a parameter,
3853 returns FALSE otherwise. */
3855 bool
3857 {
3858 tree olddecl;
3860 /* If we're not in a template, we can't possibly shadow a template
3861 parameter. */
3865 /* Figure out what we're shadowing. */
3870 /* If there's no previous binding for this name, we're not shadowing
3871 anything, let alone a template parameter. */
3875 /* If we're not shadowing a template parameter, we're done. Note
3876 that OLDDECL might be an OVERLOAD (or perhaps even an
3877 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3878 node. */
3882 /* We check for decl != olddecl to avoid bogus errors for using a
3883 name inside a class. We check TPFI to avoid duplicate errors for
3884 inline member templates. */
3890 /* Don't complain about the injected class name, as we've already
3891 complained about the class itself. */
3898 else
3903 }
3905 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3906 ORIG_LEVEL, DECL, and TYPE. */
3908 static tree
3912 tree decl,
3913 tree type)
3914 {
3925 }
3927 /* Find the canonical type parameter for the given template type
3928 parameter. Returns the canonical type parameter, which may be TYPE
3929 if no such parameter existed. */
3931 static tree
3933 {
3934 tree list;
3948 else
3949 {
3954 }
3955 }
3957 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3958 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3959 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3960 new one is created. */
3962 static tree
3964 tsubst_flags_t complain)
3965 {
3970 {
3989 /* Template template parameters need this. */
3991 {
3998 }
3999 }
4002 }
4004 /* Process information from new template parameter PARM and append it
4005 to the LIST being built. This new parameter is a non-type
4006 parameter iff IS_NON_TYPE is true. This new parameter is a
4007 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4008 is in PARM_LOC. */
4010 tree
4013 {
4022 {
4026 {
4030 else
4032 }
4035 }
4038 {
4044 {
4045 /* [temp.param]
4047 The top-level cv-qualifiers on the template-parameter are
4048 ignored when determining its type. */
4053 && !is_parameter_pack
4054 /* If we're in a nested template parameter list, the template
4055 template parameter could be a parameter pack. */
4057 {
4058 /* This template parameter is not a parameter pack, but it
4059 should be. Complain about "bare" parameter packs. */
4062 /* Recover by calling this a parameter pack. */
4064 }
4065 }
4067 /* A template parameter is not modifiable. */
4076 processing_template_decl,
4081 }
4082 else
4083 {
4084 tree t;
4088 {
4090 /* This is for distinguishing between real templates and template
4091 template parameters */
4095 }
4096 else
4097 {
4099 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4102 }
4109 processing_template_decl,
4113 }
4117 /* Build requirements for the type/template parameter.
4118 This must be done after SET_DECL_TEMPLATE_PARM_P or
4119 process_template_parm could fail. */
4124 /* Build the parameter node linking the parameter declaration,
4125 its default argument (if any), and its constraints (if any). */
4130 }
4132 /* The end of a template parameter list has been reached. Process the
4133 tree list into a parameter vector, converting each parameter into a more
4134 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4135 as PARM_DECLs. */
4137 tree
4139 {
4144 /* Pop the dummy parameter level and add the real one. */
4147 current_template_parms
4152 {
4156 }
4161 }
4163 // Explicitly indicate the end of the template parameter list. We assume
4164 // that the current template parameters have been constructed and/or
4165 // managed explicitly, as when creating new template template parameters
4166 // from a shorthand constraint.
4167 void
4169 {
4171 }
4173 /* end_template_decl is called after a template declaration is seen. */
4175 void
4177 {
4183 /* This matches the pushlevel in begin_template_parm_list. */
4188 }
4190 /* Takes a TREE_LIST representing a template parameter and convert it
4191 into an argument suitable to be passed to the type substitution
4192 functions. Note that If the TREE_LIST contains an error_mark
4193 node, the returned argument is error_mark_node. */
4195 tree
4197 {
4210 {
4214 {
4215 /* Turn this argument into a TYPE_ARGUMENT_PACK
4216 with a single element, which expands T. */
4225 }
4226 }
4227 else
4228 {
4232 {
4233 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4234 with a single element, which expands T. */
4246 }
4247 else
4249 }
4251 }
4253 /* Given a set of template parameters, return them as a set of template
4254 arguments. The template parameters are represented as a TREE_VEC, in
4255 the form documented in cp-tree.h for template arguments. */
4257 static tree
4259 {
4260 tree header;
4265 /* If there is only one level of template parameters, we do not
4266 create a TREE_VEC of TREE_VECs. Instead, we return a single
4267 TREE_VEC containing the arguments. */
4272 {
4285 else
4287 }
4290 }
4292 /* Within the declaration of a template, return the currently active
4293 template parameters as an argument TREE_VEC. */
4295 static tree
4297 {
4299 }
4301 /* Update the declared TYPE by doing any lookups which were thought to be
4302 dependent, but are not now that we know the SCOPE of the declarator. */
4304 tree
4306 {
4317 /* Don't bother building up the args in this case. */
4319 {
4320 /* tsubst in the args corresponding to the template parameters,
4321 including auto if present. Most things will be unchanged, but
4322 make_typename_type and tsubst_qualified_id will resolve
4323 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4326 tree pushed;
4328 {
4332 }
4337 }
4343 {
4346 else
4348 }
4350 }
4352 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4353 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4354 the new template is a member template. */
4356 tree
4358 {
4366 }
4368 struct template_parm_data
4369 {
4370 /* The level of the template parameters we are currently
4371 processing. */
4374 /* The index of the specialization argument we are currently
4375 processing. */
4378 /* An array whose size is the number of template parameters. The
4379 elements are nonzero if the parameter has been used in any one
4380 of the arguments processed so far. */
4383 /* An array whose size is the number of template arguments. The
4384 elements are nonzero if the argument makes use of template
4385 parameters of this level. */
4387 };
4389 /* Subroutine of push_template_decl used to see if each template
4390 parameter in a partial specialization is used in the explicit
4391 argument list. If T is of the LEVEL given in DATA (which is
4392 treated as a template_parm_data*), then DATA->PARMS is marked
4393 appropriately. */
4395 static int
4397 {
4405 {
4408 }
4410 /* Return zero so that for_each_template_parm will continue the
4411 traversal of the tree; we want to mark *every* template parm. */
4413 }
4415 /* Process the partial specialization DECL. */
4417 static tree
4419 {
4426 tree inner_parms;
4427 tree inst;
4437 /* A concept cannot be specialized. */
4439 {
4442 }
4447 /* We check that each of the template parameters given in the
4448 partial specialization is used in the argument list to the
4449 specialization. For example:
4451 template <class T> struct S;
4452 template <class T> struct S<T*>;
4454 The second declaration is OK because `T*' uses the template
4455 parameter T, whereas
4457 template <class T> struct S<int>;
4459 is no good. Even trickier is:
4461 template <class T>
4462 struct S1
4463 {
4464 template <class U>
4465 struct S2;
4466 template <class U>
4467 struct S2<T>;
4468 };
4470 The S2<T> declaration is actually invalid; it is a
4471 full-specialization. Of course,
4473 template <class U>
4474 struct S2<T (*)(U)>;
4476 or some such would have been OK. */
4484 {
4489 NULL,
4491 }
4494 {
4495 /* One of the template parms was not used in a deduced context in the
4496 specialization. */
4498 {
4502 }
4506 }
4511 /* [temp.class.spec]
4513 The argument list of the specialization shall not be identical to
4514 the implicit argument list of the primary template. */
4515 tree main_args
4518 && (!flag_concepts
4521 {
4525 else
4529 }
4531 /* A partial specialization that replaces multiple parameters of the
4532 primary template with a pack expansion is less specialized for those
4533 parameters. */
4535 {
4537 "primary template because it replaces multiple parameters "
4541 }
4543 /* [temp.class.spec]
4545 A partially specialized non-type argument expression shall not
4546 involve template parameters of the partial specialization except
4547 when the argument expression is a simple identifier.
4549 The type of a template parameter corresponding to a specialized
4550 non-type argument shall not be dependent on a parameter of the
4551 specialization.
4553 Also, we verify that pack expansions only occur at the
4554 end of the argument list. */
4558 {
4565 {
4566 /* Extract the arguments from the argument pack. We'll be
4567 iterating over these in the following loop. */
4570 }
4573 {
4575 /* Get the Jth argument in the parameter pack. */
4579 {
4580 /* Pack expansions must come at the end of the
4581 argument list. */
4584 {
4588 else
4591 }
4592 }
4595 /* We only care about the pattern. */
4601 /* This next two lines are the `argument expression is not just a
4602 simple identifier' condition and also the `specialized
4603 non-type argument' bit. */
4607 {
4611 arg);
4612 else
4613 {
4614 /* Look at the corresponding template parameter,
4615 marking which template parameters its type depends
4616 upon. */
4620 {
4621 /* We haven't yet initialized TPD2. Do so now. */
4623 /* The number of parameters here is the number in the
4624 main template, which, as checked in the assertion
4625 above, is NARGS. */
4629 }
4631 /* Mark the template parameters. But this time, we're
4632 looking for the template parameters of the main
4633 template, not in the specialization. */
4640 NULL,
4644 {
4645 /* The type depended on some template parameters.
4646 If they are fully specialized in the
4647 specialization, that's OK. */
4656 "type %qT of template argument %qE depends "
4658 "type %qT of template argument %qE depends "
4660 type,
4661 arg);
4662 }
4663 }
4664 }
4665 }
4666 }
4668 /* We should only get here once. */
4672 // Build the template decl.
4682 /* We didn't register this in check_explicit_specialization so we could
4683 wait until the constraints were set. */
4685 else
4695 {
4701 {
4709 "declaration of %qD ambiguates earlier template "
4713 "partial specialization of %qD after instantiation "
4715 }
4716 }
4719 }
4721 /* PARM is a template parameter of some form; return the corresponding
4722 TEMPLATE_PARM_INDEX. */
4724 static tree
4726 {
4739 }
4741 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4742 parameter packs used by the template parameter PARM. */
4744 static void
4746 {
4747 /* A type parm can't refer to another parm. */
4751 {
4755 }
4762 }
4764 /* PARM is a template parameter pack. Return any parameter packs used in
4765 its type or the type of any of its template parameters. If there are
4766 any such packs, it will be instantiated into a fixed template parameter
4767 list by partial instantiation rather than be fully deduced. */
4769 tree
4771 {
4772 /* This can only be true in a member template. */
4775 /* This can only be true for a parameter pack. */
4778 /* A type parm can't refer to another parm. */
4792 }
4794 /* Check that a template declaration's use of default arguments and
4795 parameter packs is not invalid. Here, PARMS are the template
4796 parameters. IS_PRIMARY is true if DECL is the thing declared by
4797 a primary template. IS_PARTIAL is true if DECL is a partial
4798 specialization.
4800 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4801 declaration (but not a definition); 1 indicates a declaration, 2
4802 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4803 emitted for extraneous default arguments.
4805 Returns TRUE if there were no errors found, FALSE otherwise. */
4807 bool
4810 {
4813 tree parm_level;
4816 /* [temp.param]
4818 A default template-argument shall not be specified in a
4819 function template declaration or a function template definition, nor
4820 in the template-parameter-list of the definition of a member of a
4821 class template. */
4825 /* You can't have a function template declaration in a local
4826 scope, nor you can you define a member of a class template in a
4827 local scope. */
4835 /* A lambda doesn't have an explicit declaration; don't complain
4836 about the parms of the enclosing class. */
4843 /* If this is either a friend defined in the scope of the class
4844 or a member function. */
4850 /* And, if it was a member function, it really was defined in
4851 the scope of the class. */
4854 /* We already checked these parameters when the template was
4855 declared, so there's no need to do it again now. This function
4856 was defined in class scope, but we're processing its body now
4857 that the class is complete. */
4860 /* Core issue 226 (C++0x only): the following only applies to class
4861 templates. */
4864 {
4865 /* [temp.param]
4867 If a template-parameter has a default template-argument, all
4868 subsequent template-parameters shall have a default
4869 template-argument supplied. */
4871 {
4878 {
4888 {
4890 /* For better subsequent error-recovery, we indicate that
4891 there should have been a default argument. */
4894 }
4896 && !is_friend_decl
4897 /* Don't complain about an enclosing partial
4898 specialization. */
4903 /* A fixed parameter pack will be partially
4904 instantiated into a fixed length list. */
4906 {
4907 /* A primary class template can only have one
4908 parameter pack, at the end of the template
4909 parameter list. */
4917 }
4918 }
4919 }
4920 }
4923 || is_partial
4924 || !is_primary
4926 /* For an ordinary class template, default template arguments are
4927 allowed at the innermost level, e.g.:
4928 template <class T = int>
4929 struct S {};
4930 but, in a partial specialization, they're not allowed even
4931 there, as we have in [temp.class.spec]:
4933 The template parameter list of a specialization shall not
4934 contain default template argument values.
4936 So, for a partial specialization, or for a function template
4937 (in C++98/C++03), we look at all of them. */
4938 ;
4939 else
4940 /* But, for a primary class template that is not a partial
4941 specialization we look at all template parameters except the
4942 innermost ones. */
4945 /* Figure out what error message to issue. */
4960 else
4961 /* Per [temp.param]/9, "A default template-argument shall not be
4962 specified in the template-parameter-lists of the definition of
4963 a member of a class template that appears outside of the member's
4964 class.", thus if we aren't handling a member of a class template
4965 there is no need to examine the parameters. */
4969 /* If we're inside a class definition, there's no need to
4970 examine the parameters to the class itself. On the one
4971 hand, they will be checked when the class is defined, and,
4972 on the other, default arguments are valid in things like:
4973 template <class T = double>
4974 struct S { template <class U> void f(U); };
4975 Here the default argument for `S' has no bearing on the
4976 declaration of `f'. */
4978 else
4979 /* Check everything. */
4985 {
4992 {
4997 {
4999 {
5006 }
5008 /* Clear out the default argument so that we are not
5009 confused later. */
5011 }
5012 }
5014 /* At this point, if we're still interested in issuing messages,
5015 they must apply to classes surrounding the object declared. */
5019 }
5022 }
5024 /* Worker for push_template_decl_real, called via
5025 for_each_template_parm. DATA is really an int, indicating the
5026 level of the parameters we are interested in. If T is a template
5027 parameter of that level, return nonzero. */
5029 static int
5031 {
5037 else
5040 }
5042 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5043 parameters given by current_template_args, or reuses a
5044 previously existing one, if appropriate. Returns the DECL, or an
5045 equivalent one, if it is replaced via a call to duplicate_decls.
5047 If IS_FRIEND is true, DECL is a friend declaration. */
5049 tree
5051 {
5052 tree tmpl;
5053 tree args;
5054 tree info;
5055 tree ctx;
5059 /* True if the template is a member template, in the sense of
5060 [temp.mem]. */
5066 /* See if this is a partial specialization. */
5079 /* For a friend, we want the context of the friend function, not
5080 the type of which it is a friend. */
5084 /* In the case of a virtual function, we want the class in which
5085 it is defined. */
5087 else
5088 /* Otherwise, if we're currently defining some class, the DECL
5089 is assumed to be a member of the class. */
5098 /* See if this is a primary template. */
5101 /* A friend template that specifies a class context, i.e.
5102 template <typename T> friend void A<T>::f();
5103 is not primary. */
5108 else
5112 {
5119 {
5122 }
5124 {
5126 {
5129 }
5131 {
5132 /* [temp.mem]
5134 A destructor shall not be a member template. */
5137 }
5144 {
5145 /* [basic.stc.dynamic.allocation]
5147 An allocation function can be a function
5148 template. ... Template allocation functions shall
5149 have two or more parameters. */
5152 }
5153 }
5159 /* alias-declaration */
5163 else
5164 {
5167 }
5168 }
5170 /* Check to see that the rules regarding the use of default
5171 arguments are not being violated. */
5175 /* Ensure that there are no parameter packs in the type of this
5176 declaration that have not been expanded. */
5178 {
5179 /* Check each of the arguments individually to see if there are
5180 any bare parameter packs. */
5186 {
5189 {
5190 /* This is a PARM_DECL that contains unexpanded parameter
5191 packs. We have already complained about this in the
5192 check_for_bare_parameter_packs call, so just replace
5193 these types with ERROR_MARK_NODE. */
5196 }
5200 }
5202 /* Check for bare parameter packs in the return type and the
5203 exception specifiers. */
5205 /* Errors were already issued, set return type to int
5206 as the frontend doesn't expect error_mark_node as
5207 the return type. */
5211 }
5216 {
5219 }
5232 {
5237 /* If DECL is a TYPE_DECL for a class-template, then there won't
5238 be DECL_LANG_SPECIFIC. The information equivalent to
5239 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5243 {
5244 /* Since a template declaration already existed for this
5245 class-type, we must be redeclaring it here. Make sure
5246 that the redeclaration is valid. */
5248 current_template_parms,
5250 /* We don't need to create a new TEMPLATE_DECL; just use the
5251 one we already had. */
5253 }
5254 else
5255 {
5257 member_template_p);
5262 {
5263 /* A specialization of a member template of a template
5264 class. */
5268 }
5269 }
5270 }
5271 else
5272 {
5278 {
5281 }
5289 {
5290 tree new_tmpl;
5292 /* The declaration is a specialization of a member
5293 template, declared outside the class. Therefore, the
5294 innermost template arguments will be NULL, so we
5295 replace them with the arguments determined by the
5296 earlier call to check_explicit_specialization. */
5299 new_tmpl
5301 member_template_p);
5311 args,
5314 }
5316 /* Make sure the template headers we got make sense. */
5321 {
5326 }
5327 else
5329 {
5334 {
5338 else
5342 /* Avoid crash in import_export_decl. */
5345 }
5350 /* Can happen in erroneous input. */
5352 else
5354 }
5356 /* Check that the parms are used in the appropriate qualifying scopes
5357 in the declarator. */
5361 {
5367 /* Avoid crash in import_export_decl. */
5370 }
5371 }
5376 /* Push template declarations for global functions and types. Note
5377 that we do not try to push a global template friend declared in a
5378 template class; such a thing may well depend on the template
5379 parameters of the class. */
5382 {
5387 /* Hide template friend classes that haven't been declared yet. */
5389 {
5392 }
5393 }
5396 {
5402 {
5405 /* It is a conversion operator. See if the type converted to
5406 depends on innermost template operands. */
5409 depth))
5411 }
5413 /* Give template template parms a DECL_CONTEXT of the template
5414 for which they are a parameter. */
5417 {
5421 }
5427 }
5429 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5430 back to its most general template. If TMPL is a specialization,
5431 ARGS may only have the innermost set of arguments. Add the missing
5432 argument levels if necessary. */
5440 else
5441 {
5446 }
5449 && !is_friend
5452 /* Set DECL_COMDAT on template instantiations; if we force
5453 them to be emitted by explicit instantiation or -frepo,
5454 mark_needed will tell cgraph to do the right thing. */
5458 }
5460 tree
5462 {
5464 }
5466 /* FN is an inheriting constructor that inherits from the constructor
5467 template INHERITED; turn FN into a constructor template with a matching
5468 template header. */
5470 tree
5472 {
5473 tree inner_parms
5476 tree parms
5487 }
5489 /* Called when a class template TYPE is redeclared with the indicated
5490 template PARMS, e.g.:
5492 template <class T> struct S;
5493 template <class T> struct S {}; */
5495 bool
5497 {
5498 tree tmpl;
5499 tree tmpl_parms;
5503 {
5506 }
5510 /* The type is nested in some template class. Nothing to worry
5511 about here; there are no new template parameters for the nested
5512 type. */
5516 {
5518 tmpl);
5520 }
5526 {
5536 }
5539 {
5540 tree tmpl_parm;
5541 tree parm;
5542 tree tmpl_default;
5543 tree parm_default;
5557 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5558 TEMPLATE_DECL. */
5568 {
5572 }
5575 {
5576 /* We have in [temp.param]:
5578 A template-parameter may not be given default arguments
5579 by two different declarations in the same scope. */
5584 }
5587 /* Update the previous template parameters (which are the ones
5588 that will really count) with the new default value. */
5591 /* Update the new parameters, too; they'll be used as the
5592 parameters for any members. */
5595 /* Give each template template parm in this redeclaration a
5596 DECL_CONTEXT of the template for which they are a parameter. */
5598 {
5601 }
5602 }
5604 // Cannot redeclare a class template with a different set of constraints.
5606 {
5611 }
5614 }
5616 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5617 to be used when the caller has already checked
5618 (processing_template_decl
5619 && !instantiation_dependent_expression_p (expr)
5620 && potential_constant_expression (expr))
5621 and cleared processing_template_decl. */
5623 tree
5625 {
5628 complain,
5632 }
5634 /* Simplify EXPR if it is a non-dependent expression. Returns the
5635 (possibly simplified) expression. */
5637 tree
5639 {
5643 /* If we're in a template, but EXPR isn't value dependent, simplify
5644 it. We're supposed to treat:
5646 template <typename T> void f(T[1 + 1]);
5647 template <typename T> void f(T[2]);
5649 as two declarations of the same function, for example. */
5653 {
5654 processing_template_decl_sentinel s;
5656 }
5658 }
5660 tree
5662 {
5664 }
5666 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5667 an uninstantiated expression. */
5669 tree
5671 {
5675 {
5679 else
5680 {
5681 processing_template_decl_sentinel s;
5683 }
5684 }
5686 }
5688 /* True iff T is a specialization of a variable template. */
5690 bool
5692 {
5697 }
5699 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5700 template declaration, or a TYPE_DECL for an alias declaration. */
5702 bool
5704 {
5712 }
5714 /* Return TRUE iff T is a specialization of an alias template. */
5716 bool
5718 {
5719 /* It's an alias template specialization if it's an alias and its
5720 TYPE_NAME is a specialization of a primary template. */
5722 {
5726 {
5729 }
5730 }
5732 }
5734 /* An alias template is complex from a SFINAE perspective if a template-id
5735 using that alias can be ill-formed when the expansion is not, as with
5736 the void_t template. We determine this by checking whether the
5737 expansion for the alias template uses all its template parameters. */
5739 struct uses_all_template_parms_data
5740 {
5743 };
5745 static int
5747 {
5755 }
5757 static bool
5759 {
5774 }
5776 /* Return TRUE iff T is a specialization of a complex alias template with
5777 dependent template-arguments. */
5779 bool
5781 {
5784 && (any_dependent_template_arguments_p
5786 }
5788 /* Return the number of innermost template parameters in TMPL. */
5790 static int
5792 {
5795 }
5797 /* Return either TMPL or another template that it is equivalent to under DR
5798 1286: An alias that just changes the name of a template is equivalent to
5799 the other template. */
5801 static tree
5803 {
5806 {
5809 {
5814 {
5815 tree alias_args = INNERMOST_TEMPLATE_ARGS
5819 /* The alias type is equivalent to the pattern of the
5820 underlying template, so strip the alias. */
5823 }
5824 }
5826 }
5828 }
5830 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5831 must be a function or a pointer-to-function type, as specified
5832 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5833 and check that the resulting function has external linkage. */
5835 static tree
5837 tsubst_flags_t complain)
5838 {
5841 linkage_kind linkage;
5853 /* [temp.arg.nontype]/1
5855 A template-argument for a non-type, non-template template-parameter
5856 shall be one of:
5857 [...]
5858 -- the address of an object or function with external [C++11: or
5859 internal] linkage. */
5862 {
5864 {
5870 else
5873 }
5875 }
5879 {
5881 {
5886 else
5890 }
5892 }
5895 }
5897 /* Subroutine of convert_nontype_argument.
5898 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5899 Emit an error otherwise. */
5901 static bool
5903 tsubst_flags_t complain)
5904 {
5915 {
5919 }
5921 }
5923 /* Returns TRUE iff the address of OP is value-dependent.
5925 14.6.2.4 [temp.dep.temp]:
5926 A non-integral non-type template-argument is dependent if its type is
5927 dependent or it has either of the following forms
5928 qualified-id
5929 & qualified-id
5930 and contains a nested-name-specifier which specifies a class-name that
5931 names a dependent type.
5933 We generalize this to just say that the address of a member of a
5934 dependent class is value-dependent; the above doesn't cover the
5935 address of a static data member named with an unqualified-id. */
5937 static bool
5939 {
5940 /* We could use get_inner_reference here, but there's no need;
5941 this is only relevant for template non-type arguments, which
5942 can only be expressed as &id-expression. */
5944 {
5948 }
5951 }
5953 /* The next set of functions are used for providing helpful explanatory
5954 diagnostics for failed overload resolution. Their messages should be
5955 indented by two spaces for consistency with the messages in
5956 call.c */
5958 static int
5960 {
5962 }
5964 static int
5966 {
5971 }
5973 static int
5975 {
5977 }
5979 static int
5981 {
5987 }
5989 static int
5991 {
5995 }
5997 static int
5999 {
6002 " template parameter %qD is not a parameter pack, but "
6006 }
6008 static int
6010 {
6013 " template argument %qE does not match "
6017 }
6019 static int
6021 {
6025 }
6027 static int
6029 {
6035 }
6037 static int
6039 {
6041 {
6046 else
6048 " deduced conflicting values for non-type parameter "
6050 }
6052 }
6054 static int
6056 {
6059 " variable-sized array type %qT is not "
6061 arg);
6063 }
6065 static int
6067 {
6071 arg);
6073 }
6075 static int
6077 {
6079 {
6085 else
6090 }
6092 }
6094 static int
6096 {
6098 }
6100 static int
6103 {
6105 }
6107 static int
6110 {
6116 }
6118 static int
6121 {
6124 {
6132 }
6134 }
6136 static int
6138 {
6141 " template parameters of a template template argument are "
6144 }
6146 static int
6148 {
6154 }
6156 static int
6158 {
6163 }
6165 static int
6167 {
6171 arg);
6173 }
6175 /* Attempt to convert the non-type template parameter EXPR to the
6176 indicated TYPE. If the conversion is successful, return the
6177 converted value. If the conversion is unsuccessful, return
6178 NULL_TREE if we issued an error message, or error_mark_node if we
6179 did not. We issue error messages for out-and-out bad template
6180 parameters, but not simply because the conversion failed, since we
6181 might be just trying to do argument deduction. Both TYPE and EXPR
6182 must be non-dependent.
6184 The conversion follows the special rules described in
6185 [temp.arg.nontype], and it is much more strict than an implicit
6186 conversion.
6188 This function is called twice for each template argument (see
6189 lookup_template_class for a more accurate description of this
6190 problem). This means that we need to handle expressions which
6191 are not valid in a C++ source, but can be created from the
6192 first call (for instance, casts to perform conversions). These
6193 hacks can go away after we fix the double coercion problem. */
6195 static tree
6197 {
6198 tree expr_type;
6200 /* Detect immediately string literals as invalid non-type argument.
6201 This special-case is not needed for correctness (we would easily
6202 catch this later), but only to provide better diagnostic for this
6203 common user mistake. As suggested by DR 100, we do not mention
6204 linkage issues in the diagnostic as this is not the point. */
6205 /* FIXME we're making this OK. */
6207 {
6213 }
6215 /* Add the ADDR_EXPR now for the benefit of
6216 value_dependent_expression_p. */
6219 {
6223 }
6225 /* If we are in a template, EXPR may be non-dependent, but still
6226 have a syntactic, rather than semantic, form. For example, EXPR
6227 might be a SCOPE_REF, rather than the VAR_DECL to which the
6228 SCOPE_REF refers. Preserving the qualifying scope is necessary
6229 so that access checking can be performed when the template is
6230 instantiated -- but here we need the resolved form so that we can
6231 convert the argument. */
6237 && processing_template_decl
6246 else
6249 /* If the argument is non-dependent, perform any conversions in
6250 non-dependent context as well. */
6255 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6256 to a non-type argument of "nullptr". */
6260 /* In C++11, integral or enumeration non-type template arguments can be
6261 arbitrary constant expressions. Pointer and pointer to
6262 member arguments can be general constant expressions that evaluate
6263 to a null value, but otherwise still need to be of a specific form. */
6265 {
6267 /* A PTRMEM_CST is already constant, and a valid template
6268 argument for a parameter of pointer to member type, we just want
6269 to leave it in that form rather than lower it to a
6274 {
6278 {
6282 }
6283 }
6285 {
6290 }
6291 }
6293 /* HACK: Due to double coercion, we can get a
6294 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6295 which is the tree that we built on the first call (see
6296 below when coercing to reference to object or to reference to
6297 function). We just strip everything and get to the arg.
6298 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6299 for examples. */
6301 {
6307 {
6308 /* ??? Maybe we could use convert_from_reference here, but we
6309 would need to relax its constraints because the NOP_EXPR
6310 could actually change the type to something more cv-qualified,
6311 and this is not folded by convert_from_reference. */
6316 && (same_type_ignoring_top_level_qualifiers_p
6319 {
6322 }
6323 }
6324 }
6326 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
6327 parameter is a pointer to object, through decay and
6328 qualification conversion. Let's strip everything. */
6330 {
6335 {
6336 /* Skip the ADDR_EXPR only if it is part of the decay for
6337 an array. Otherwise, it is part of the original argument
6338 in the source code. */
6343 }
6344 }
6346 /* [temp.arg.nontype]/5, bullet 1
6348 For a non-type template-parameter of integral or enumeration type,
6349 integral promotions (_conv.prom_) and integral conversions
6350 (_conv.integral_) are applied. */
6352 {
6361 /* Notice that there are constant expressions like '4 % 0' which
6362 do not fold into integer constants. */
6364 {
6366 {
6377 /* else cxx_constant_value complained but gave us
6378 a real constant, so go ahead. */
6380 }
6381 else
6383 }
6385 /* Avoid typedef problems. */
6388 }
6389 /* [temp.arg.nontype]/5, bullet 2
6391 For a non-type template-parameter of type pointer to object,
6392 qualification conversions (_conv.qual_) and the array-to-pointer
6393 conversion (_conv.array_) are applied. */
6395 {
6396 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6398 A template-argument for a non-type, non-template template-parameter
6399 shall be one of: [...]
6401 -- the name of a non-type template-parameter;
6402 -- the address of an object or function with external linkage, [...]
6403 expressed as "& id-expression" where the & is optional if the name
6404 refers to a function or array, or if the corresponding
6405 template-parameter is a reference.
6407 Here, we do not care about functions, as they are invalid anyway
6408 for a parameter of type pointer-to-object. */
6411 /* Non-type template parameters are OK. */
6412 ;
6417 {
6419 {
6422 "because %qD is a variable, not the address of "
6425 }
6427 {
6433 }
6434 /* Other values, like integer constants, might be valid
6435 non-type arguments of some other type. */
6437 }
6438 else
6439 {
6440 tree decl;
6445 {
6450 }
6452 {
6458 }
6460 {
6465 }
6466 }
6475 }
6476 /* [temp.arg.nontype]/5, bullet 3
6478 For a non-type template-parameter of type reference to object, no
6479 conversions apply. The type referred to by the reference may be more
6480 cv-qualified than the (otherwise identical) type of the
6481 template-argument. The template-parameter is bound directly to the
6482 template-argument, which must be an lvalue. */
6484 {
6486 expr_type))
6490 {
6495 }
6498 {
6503 }
6505 /* [temp.arg.nontype]/1
6507 A template-argument for a non-type, non-template template-parameter
6508 shall be one of: [...]
6510 -- the address of an object or function with external linkage. */
6513 {
6516 {
6519 "because a reference variable does not have a constant "
6522 }
6523 }
6526 {
6532 }
6534 /* DR 1155 allows internal linkage in C++11 and up. */
6537 {
6543 }
6546 }
6547 /* [temp.arg.nontype]/5, bullet 4
6549 For a non-type template-parameter of type pointer to function, only
6550 the function-to-pointer conversion (_conv.func_) is applied. If the
6551 template-argument represents a set of overloaded functions (or a
6552 pointer to such), the matching function is selected from the set
6553 (_over.over_). */
6555 {
6556 /* If the argument is a template-id, we might not have enough
6557 context information to decay the pointer. */
6559 {
6563 }
6566 /* Null pointer values are OK in C++11. */
6572 }
6573 /* [temp.arg.nontype]/5, bullet 5
6575 For a non-type template-parameter of type reference to function, no
6576 conversions apply. If the template-argument represents a set of
6577 overloaded functions, the matching function is selected from the set
6578 (_over.over_). */
6580 {
6582 {
6584 {
6589 }
6591 }
6598 }
6599 /* [temp.arg.nontype]/5, bullet 6
6601 For a non-type template-parameter of type pointer to member function,
6602 no conversions apply. If the template-argument represents a set of
6603 overloaded member functions, the matching member function is selected
6604 from the set (_over.over_). */
6606 {
6611 /* [temp.arg.nontype] bullet 1 says the pointer to member
6612 expression must be a pointer-to-member constant. */
6616 /* There is no way to disable standard conversions in
6617 resolve_address_of_overloaded_function (called by
6618 instantiate_type). It is possible that the call succeeded by
6619 converting &B::I to &D::I (where B is a base of D), so we need
6620 to reject this conversion here.
6622 Actually, even if there was a way to disable standard conversions,
6623 it would still be better to reject them here so that we can
6624 provide a superior diagnostic. */
6626 {
6628 {
6632 /* If we are just one standard conversion off, explain. */
6636 }
6638 }
6639 }
6640 /* [temp.arg.nontype]/5, bullet 7
6642 For a non-type template-parameter of type pointer to data member,
6643 qualification conversions (_conv.qual_) are applied. */
6645 {
6646 /* [temp.arg.nontype] bullet 1 says the pointer to member
6647 expression must be a pointer-to-member constant. */
6654 }
6656 {
6658 {
6663 }
6665 }
6666 /* A template non-type parameter must be one of the above. */
6667 else
6670 /* Sanity check: did we actually convert the argument to the
6671 right type? */
6675 }
6677 /* Subroutine of coerce_template_template_parms, which returns 1 if
6678 PARM_PARM and ARG_PARM match using the rule for the template
6679 parameters of template template parameters. Both PARM and ARG are
6680 template parameters; the rest of the arguments are the same as for
6681 coerce_template_template_parms.
6682 */
6683 static int
6685 tree arg,
6686 tsubst_flags_t complain,
6687 tree in_decl,
6688 tree outer_args)
6689 {
6698 {
6700 /* We encounter instantiations of templates like
6701 template <template <template <class> class> class TT>
6702 class C; */
6703 {
6710 }
6711 /* Fall through. */
6716 /* Argument is a parameter pack but parameter is not. */
6721 /* The tsubst call is used to handle cases such as
6723 template <int> class C {};
6724 template <class T, template <T> class TT> class D {};
6725 D<int, C> d;
6727 i.e. the parameter list of TT depends on earlier parameters. */
6729 {
6734 }
6738 /* Argument is a parameter pack but parameter is not. */
6745 }
6748 }
6751 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6752 template template parameters. Both PARM_PARMS and ARG_PARMS are
6753 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6754 or PARM_DECL.
6756 Consider the example:
6757 template <class T> class A;
6758 template<template <class U> class TT> class B;
6760 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6761 the parameters to A, and OUTER_ARGS contains A. */
6763 static int
6765 tree arg_parms,
6766 tsubst_flags_t complain,
6767 tree in_decl,
6768 tree outer_args)
6769 {
6780 /* Determine whether we have a parameter pack at the end of the
6781 template template parameter's template parameter list. */
6783 {
6790 {
6804 }
6805 }
6811 /* Check all of the template parameters except the parameter pack at
6812 the end (if any). */
6814 {
6823 outer_args))
6826 }
6829 {
6830 /* Check each of the template parameters in the template
6831 argument against the template parameter pack at the end of
6832 the template template parameter. */
6839 {
6846 outer_args))
6848 }
6849 }
6852 }
6854 /* Verifies that the deduced template arguments (in TARGS) for the
6855 template template parameters (in TPARMS) represent valid bindings,
6856 by comparing the template parameter list of each template argument
6857 to the template parameter list of its corresponding template
6858 template parameter, in accordance with DR150. This
6859 routine can only be called after all template arguments have been
6860 deduced. It will return TRUE if all of the template template
6861 parameter bindings are okay, FALSE otherwise. */
6862 bool
6864 {
6868 /* We're dealing with template parms in this process. */
6874 {
6879 {
6884 {
6885 /* Look inside the argument pack. */
6888 }
6891 {
6895 /* Extract the next argument from the argument
6896 pack. */
6900 /* Look at the pattern of the pack expansion. */
6903 /* Extract the template parameters from the template
6904 argument. */
6910 /* Verify that we can coerce the template template
6911 parameters from the template argument to the template
6912 parameter. This requires an exact match. */
6914 && !coerce_template_template_parms
6916 targ_parms,
6917 tf_none,
6918 tparm,
6919 targs))
6920 {
6923 }
6924 }
6925 }
6926 }
6928 out:
6932 }
6934 /* Since type attributes aren't mangled, we need to strip them from
6935 template type arguments. */
6937 static tree
6939 {
6948 }
6950 // A template declaration can be substituted for a constrained
6951 // template template parameter only when the argument is more
6952 // constrained than the parameter.
6953 static bool
6955 {
6958 /* For now, allow constrained template template arguments
6959 and unconstrained template template parameters. */
6965 // If the template parameter is constrained, we need to rewrite its
6966 // constraints in terms of the ARG's template parameters. This ensures
6967 // that all of the template parameter types will have the same depth.
6968 //
6969 // Note that this is only valid when coerce_template_template_parm is
6970 // true for the innermost template parameters of PARM and ARG. In other
6971 // words, because coercion is successful, this conversion will be valid.
6973 {
6980 }
6983 }
6985 // Convert a placeholder argument into a binding to the original
6986 // parameter. The original parameter is saved as the TREE_TYPE of
6987 // ARG.
6990 {
6993 }
6995 /* Convert the indicated template ARG as necessary to match the
6996 indicated template PARM. Returns the converted ARG, or
6997 error_mark_node if the conversion was unsuccessful. Error and
6998 warning messages are issued under control of COMPLAIN. This
6999 conversion is for the Ith parameter in the parameter list. ARGS is
7000 the full set of template arguments deduced so far. */
7002 static tree
7004 tree arg,
7005 tree args,
7006 tsubst_flags_t complain,
7008 tree in_decl)
7009 {
7010 tree orig_arg;
7011 tree val;
7017 /* Trivially convert placeholders. */
7023 {
7024 /* The template argument was the name of some
7025 member function. That's usually
7026 invalid, but static members are OK. In any
7027 case, grab the underlying fields/functions
7028 and issue an error later if required. */
7031 }
7039 /* When determining whether an argument pack expansion is a template,
7040 look at the pattern. */
7044 /* Deal with an injected-class-name used as a template template arg. */
7046 {
7049 {
7059 }
7060 }
7062 is_tmpl_type =
7078 {
7080 {
7084 }
7087 "to refer to a type member of a template parameter, "
7092 typename_type,
7093 complain);
7096 }
7098 {
7100 {
7102 {
7114 else
7117 }
7118 }
7120 }
7122 {
7124 {
7131 else
7134 }
7136 }
7139 {
7141 {
7145 /* The number of argument required is not known yet.
7146 Just accept it for now. */
7148 else
7149 {
7151 tree argparm;
7153 /* Strip alias templates that are equivalent to another
7154 template. */
7160 args))
7161 {
7164 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7165 TEMPLATE_DECL. */
7167 {
7172 }
7173 }
7174 else
7175 {
7177 {
7184 }
7187 }
7189 // Check that the constraints are compatible before allowing the
7190 // substitution.
7193 {
7195 {
7201 }
7203 }
7204 }
7205 }
7206 else
7208 /* We only form one instance of each template specialization.
7209 Therefore, if we use a non-canonical variant (i.e., a
7210 typedef), any future messages referring to the type will use
7211 the typedef, which is confusing if those future uses do not
7212 themselves also use the typedef. */
7215 }
7216 else
7217 {
7224 {
7227 else
7228 {
7229 /* Not sure if this is reachable, but it doesn't hurt
7230 to be robust. */
7233 }
7234 }
7237 /* We used to call digest_init here. However, digest_init
7238 will report errors, which we don't want when complain
7239 is zero. More importantly, digest_init will try too
7240 hard to convert things: for example, `0' should not be
7241 converted to pointer type at this point according to
7242 the standard. Accepting this is not merely an
7243 extension, since deciding whether or not these
7244 conversions can occur is part of determining which
7245 function template to call, or whether a given explicit
7246 argument specification is valid. */
7248 else
7249 {
7252 }
7260 {
7261 /* Reject template arguments that are references to built-in
7262 functions with no library fallbacks. */
7270 }
7273 {
7274 /* Strip typedefs from the SCOPE_REF. */
7277 complain);
7280 }
7281 }
7284 }
7286 /* Coerces the remaining template arguments in INNER_ARGS (from
7287 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7288 Returns the coerced argument pack. PARM_IDX is the position of this
7289 parameter in the template parameter list. ARGS is the original
7290 template argument list. */
7291 static tree
7294 tree args,
7295 tree inner_args,
7297 tree new_args,
7299 tree in_decl,
7300 tsubst_flags_t complain)
7301 {
7304 tree packed_args;
7305 tree argument_pack;
7312 {
7313 /* When the template parameter is a non-type template parameter pack
7314 or template template parameter pack whose type or template
7315 parameters use parameter packs, we know exactly how many arguments
7316 we are looking for. Build a vector of the instantiated decls for
7317 these template parameters in PACKED_PARMS. */
7318 /* We can't use make_pack_expansion here because it would interpret a
7319 _DECL as a use rather than a declaration. */
7333 /* If we're doing a partial instantiation of a member template,
7334 verify that all of the types used for the non-type
7335 template parameter pack are, in fact, valid for non-type
7336 template parameters. */
7339 {
7342 {
7346 }
7347 /* We don't know how many args we have yet, just
7348 use the unconverted ones for now. */
7350 }
7353 }
7354 /* Check if we have a placeholder pack, which indicates we're
7355 in the context of a introduction list. In that case we want
7356 to match this pack to the single placeholder. */
7360 {
7363 }
7364 else
7367 /* Convert the remaining arguments, which will be a part of the
7368 parameter pack "parm". */
7370 {
7376 {
7377 /* Once we've packed as many args as we have types, stop. */
7381 /* We don't know how many args we have yet, just
7382 use the unconverted ones for now. */
7384 else
7386 }
7389 {
7392 }
7393 else
7396 in_decl);
7400 }
7404 {
7409 }
7414 else
7415 {
7420 }
7427 }
7429 /* Returns the number of pack expansions in the template argument vector
7430 ARGS. */
7432 static int
7434 {
7439 {
7443 }
7445 }
7447 /* Convert all template arguments to their appropriate types, and
7448 return a vector containing the innermost resulting template
7449 arguments. If any error occurs, return error_mark_node. Error and
7450 warning messages are issued under control of COMPLAIN.
7452 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
7453 for arguments not specified in ARGS. Otherwise, if
7454 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
7455 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
7456 USE_DEFAULT_ARGS is false, then all arguments must be specified in
7457 ARGS. */
7459 static tree
7461 tree args,
7462 tree in_decl,
7463 tsubst_flags_t complain,
7466 {
7468 tree orig_inner_args;
7469 tree inner_args;
7470 tree new_args;
7471 tree new_inner_args;
7475 /* When used as a boolean value, indicates whether this is a
7476 variadic template parameter list. Since it's an int, we can also
7477 subtract it from nparms to get the number of non-variadic
7478 parameters. */
7483 /* Likewise for parameters with default arguments. */
7491 /* Determine if there are any parameter packs or default arguments. */
7493 {
7501 }
7504 /* If there are no parameters that follow a parameter pack, we need to
7505 expand any argument packs so that we can deduce a parameter pack from
7506 some non-packed args followed by an argument pack, as in variadic85.C.
7507 If there are such parameters, we need to leave argument packs intact
7508 so the arguments are assigned properly. This can happen when dealing
7509 with a nested class inside a partial specialization of a class
7510 template, as in variadic92.C, or when deducing a template parameter pack
7511 from a sub-declarator, as in variadic114.C. */
7515 /* Count any pack expansion args. */
7521 && require_all_args
7522 && !variadic_args_p
7523 && (!use_default_args
7526 {
7528 {
7530 {
7534 }
7535 else
7542 }
7545 }
7546 /* We can't pass a pack expansion to a non-pack parameter of an alias
7547 template (DR 1430). */
7551 && variadic_args_p
7553 {
7555 {
7557 {
7563 {
7566 "pack expansion argument for non-pack parameter "
7568 else
7570 "pack expansion argument for non-pack parameter "
7574 }
7575 }
7577 found:;
7578 }
7580 }
7582 /* We need to evaluate the template arguments, even though this
7583 template-id may be nested within a "sizeof". */
7592 {
7593 tree arg;
7594 tree parm;
7596 /* Get the Ith template parameter. */
7600 {
7603 }
7605 /* Calculate the next argument. */
7608 else
7613 {
7614 /* Some arguments will be placed in the
7615 template parameter pack PARM. */
7622 {
7623 /* We don't know how many args we have yet, just use the
7624 unconverted (and still packed) ones for now. */
7628 }
7632 /* Store this argument. */
7634 {
7635 lost++;
7636 /* We are done with all of the arguments. */
7638 }
7639 else
7640 {
7643 }
7646 }
7648 {
7650 {
7651 /* "If every valid specialization of a variadic template
7652 requires an empty template parameter pack, the template is
7653 ill-formed, no diagnostic required." So check that the
7654 pattern works with this parameter. */
7659 in_decl);
7661 {
7665 }
7667 /* Recover from missing typename. */
7671 /* We don't know how many args we have yet, just
7672 use the unconverted ones for now. */
7676 }
7677 }
7679 {
7680 /* There must be a default arg in this case. */
7683 /* The position of the first default template argument,
7684 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
7685 Record that. */
7689 }
7690 else
7694 {
7697 }
7699 /* This only occurs if there was an error in the template
7700 parameter list itself (which we would already have
7701 reported) that we are trying to recover from, e.g., a class
7702 template with a parameter list such as
7703 template<typename..., typename>. */
7705 else
7711 lost++;
7713 }
7718 {
7720 {
7725 }
7727 }
7737 }
7739 /* Convert all template arguments to their appropriate types, and
7740 return a vector containing the innermost resulting template
7741 arguments. If any error occurs, return error_mark_node. Error and
7742 warning messages are not issued.
7744 Note that no function argument deduction is performed, and default
7745 arguments are used to fill in unspecified arguments. */
7746 tree
7748 {
7750 }
7752 /* Convert all template arguments to their appropriate type, and
7753 instantiate default arguments as needed. This returns a vector
7754 containing the innermost resulting template arguments, or
7755 error_mark_node if unsuccessful. */
7756 tree
7758 tsubst_flags_t complain)
7759 {
7761 }
7763 /* Like coerce_template_parms. If PARMS represents all template
7764 parameters levels, this function returns a vector of vectors
7765 representing all the resulting argument levels. Note that in this
7766 case, only the innermost arguments are coerced because the
7767 outermost ones are supposed to have been coerced already.
7769 Otherwise, if PARMS represents only (the innermost) vector of
7770 parameters, this function returns a vector containing just the
7771 innermost resulting arguments. */
7773 static tree
7775 tree args,
7776 tree in_decl,
7777 tsubst_flags_t complain,
7780 {
7783 tree coerced_args;
7786 {
7788 tree level;
7794 {
7795 tree l;
7799 require_all_args,
7800 use_default_args);
7801 else
7808 }
7809 }
7810 else
7813 require_all_args,
7814 use_default_args);
7816 }
7818 /* Returns 1 if template args OT and NT are equivalent. */
7820 static int
7822 {
7829 /* For member templates */
7838 {
7855 }
7857 {
7858 /* We get here probably because we are in the middle of substituting
7859 into the pattern of a pack expansion. In that case the
7860 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
7861 interested in. So we want to use the initial pack argument for
7862 the comparison. */
7867 }
7869 {
7872 /* Don't treat an alias template specialization with dependent
7873 arguments as equivalent to its underlying type when used as a
7874 template argument; we need them to be distinct so that we
7875 substitute into the specialization arguments at instantiation
7876 time. And aliases can't be equivalent without being ==, so
7877 we don't need to look any deeper. */
7880 else
7882 }
7885 else
7886 {
7887 /* Try to treat a template non-type argument that has been converted
7888 to the parameter type as equivalent to one that hasn't yet. */
7901 }
7902 }
7904 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
7905 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
7906 NEWARG_PTR with the offending arguments if they are non-NULL. */
7908 int
7911 {
7924 {
7929 {
7935 }
7936 }
7938 }
7940 static void
7942 {
7952 /* We are called both from instantiate_decl, where we've already had a
7953 tinst_level pushed, and instantiate_template, where we haven't.
7954 Compensate. */
7965 else
7974 }
7977 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
7978 ARGLIST. Valid choices for FNS are given in the cp-tree.def
7979 documentation for TEMPLATE_ID_EXPR. */
7981 tree
7983 {
7984 tree type;
7992 {
7995 }
7998 {
8000 unknown_type_node,
8002 arglist);
8004 }
8011 }
8013 /* Within the scope of a template class S<T>, the name S gets bound
8014 (in build_self_reference) to a TYPE_DECL for the class, not a
8015 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8016 or one of its enclosing classes, and that type is a template,
8017 return the associated TEMPLATE_DECL. Otherwise, the original
8018 DECL is returned.
8020 Also handle the case when DECL is a TREE_LIST of ambiguous
8021 injected-class-names from different bases. */
8023 tree
8025 {
8029 /* DR 176: A lookup that finds an injected-class-name (10.2
8030 [class.member.lookup]) can result in an ambiguity in certain cases
8031 (for example, if it is found in more than one base class). If all of
8032 the injected-class-names that are found refer to specializations of
8033 the same class template, and if the name is followed by a
8034 template-argument-list, the reference refers to the class template
8035 itself and not a specialization thereof, and is not ambiguous. */
8037 {
8040 {
8046 }
8049 else
8051 }
8057 }
8059 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8060 parameters, find the desired type.
8062 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8064 IN_DECL, if non-NULL, is the template declaration we are trying to
8065 instantiate.
8067 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8068 the class we are looking up.
8070 Issue error and warning messages under control of COMPLAIN.
8072 If the template class is really a local class in a template
8073 function, then the FUNCTION_CONTEXT is the function in which it is
8074 being instantiated.
8076 ??? Note that this function is currently called *twice* for each
8077 template-id: the first time from the parser, while creating the
8078 incomplete type (finish_template_type), and the second type during the
8079 real instantiation (instantiate_template_class). This is surely something
8080 that we want to avoid. It also causes some problems with argument
8081 coercion (see convert_nontype_argument for more information on this). */
8083 static tree
8086 {
8088 tree t;
8091 spec_entry elt;
8092 hashval_t hash;
8095 {
8099 else
8100 {
8107 }
8110 }
8112 {
8115 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8116 an implicit typename for the second A. Deal with it. */
8121 {
8124 }
8125 }
8128 {
8131 }
8133 {
8137 }
8139 {
8142 }
8144 /* Issue an error message if we didn't find a template. */
8146 {
8150 }
8153 /* Make sure it's a user visible template, if it was named by
8154 the user. */
8157 {
8159 {
8163 }
8165 }
8169 /* An alias that just changes the name of a template is equivalent to the
8170 other template, so if any of the arguments are pack expansions, strip
8171 the alias to avoid problems with a pack expansion passed to a non-pack
8172 alias template parameter (DR 1430). */
8177 {
8178 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
8179 template arguments */
8181 tree parm;
8182 tree arglist2;
8183 tree outer;
8187 /* Consider an example where a template template parameter declared as
8189 template <class T, class U = std::allocator<T> > class TT
8191 The template parameter level of T and U are one level larger than
8192 of TT. To proper process the default argument of U, say when an
8193 instantiation `TT<int>' is seen, we need to build the full
8194 arguments containing {int} as the innermost level. Outer levels,
8195 available when not appearing as default template argument, can be
8196 obtained from the arguments of the enclosing template.
8198 Suppose that TT is later substituted with std::vector. The above
8199 instantiation is `TT<int, std::allocator<T> >' with TT at
8200 level 1, and T at level 2, while the template arguments at level 1
8201 becomes {std::vector} and the inner level 2 is {int}. */
8207 {
8208 /* This is an argument of the current template, so we haven't set
8209 DECL_CONTEXT yet. */
8210 tree relevant_template_parms;
8212 /* Parameter levels that are greater than the level of the given
8213 template template parm are irrelevant. */
8220 }
8226 complain,
8236 }
8237 else
8238 {
8240 tree gen_tmpl;
8241 tree type_decl;
8249 /* An error occurred while building the template TEMPL, and a
8250 diagnostic has most certainly been emitted for that
8251 already. Let's propagate that error. */
8260 {
8261 /* We've been given an incomplete set of template arguments.
8262 For example, given:
8264 template <class T> struct S1 {
8265 template <class U> struct S2 {};
8266 template <class U> struct S2<U*> {};
8267 };
8269 we will be called with an ARGLIST of `U*', but the
8270 TEMPLATE will be `template <class T> template
8271 <class U> struct S1<T>::S2'. We must fill in the missing
8272 arguments. */
8273 arglist
8275 arglist);
8277 }
8279 /* Now we should have enough arguments. */
8282 /* From here on, we're only interested in the most general
8283 template. */
8285 /* Calculate the BOUND_ARGS. These will be the args that are
8286 actually tsubst'd into the definition to create the
8287 instantiation. */
8289 complain,
8294 /* We were unable to bind the arguments. */
8297 /* In the scope of a template class, explicit references to the
8298 template class refer to the type of the template, not any
8299 instantiation of it. For example, in:
8301 template <class T> class C { void f(C<T>); }
8303 the `C<T>' is just the same as `C'. Outside of the
8304 class, however, such a reference is an instantiation. */
8308 /* comp_template_args is expensive, check it last. */
8310 arglist))
8313 /* If we already have this specialization, return it. */
8323 /* If the the template's constraints are not satisfied,
8324 then we cannot form a valid type.
8326 Note that the check is deferred until after the hash
8327 lookup. This prevents redundant checks on previously
8328 instantiated specializations. */
8330 {
8332 {
8335 }
8337 }
8341 /* If the deduced arguments are invalid, then the binding
8342 failed. */
8346 complain))
8353 {
8358 }
8368 /* Create the type. */
8370 {
8371 /* The user referred to a specialization of an alias
8372 template represented by GEN_TMPL.
8374 [temp.alias]/2 says:
8376 When a template-id refers to the specialization of an
8377 alias template, it is equivalent to the associated
8378 type obtained by substitution of its
8379 template-arguments for the template-parameters in the
8380 type-id of the alias template. */
8383 /* Note that the call above (by indirectly calling
8384 register_specialization in tsubst_decl) registers the
8385 TYPE_DECL representing the specialization of the alias
8386 template. So next time someone substitutes ARGLIST for
8387 the template parms into the alias template (GEN_TMPL),
8388 she'll get that TYPE_DECL back. */
8392 }
8394 {
8396 {
8405 }
8406 else
8407 {
8408 /* We don't want to call start_enum for this type, since
8409 the values for the enumeration constants may involve
8410 template parameters. And, no one should be interested
8411 in the enumeration constants for such a type. */
8414 }
8418 }
8420 {
8427 /* A local class. Make sure the decl gets registered properly. */
8432 /* This instantiation is another name for the primary
8433 template type. Set the TYPE_CANONICAL field
8434 appropriately. */
8437 /* Some of the template arguments require structural
8438 equality testing, so this template class requires
8439 structural equality testing. */
8441 }
8442 else
8445 /* If we called start_enum or pushtag above, this information
8446 will already be set up. */
8448 {
8455 }
8456 else
8460 {
8466 {
8469 }
8470 }
8474 {
8478 {
8479 tree attributes
8483 ;
8486 else
8491 }
8492 }
8494 /* Let's consider the explicit specialization of a member
8495 of a class template specialization that is implicitly instantiated,
8496 e.g.:
8497 template<class T>
8498 struct S
8499 {
8500 template<class U> struct M {}; //#0
8501 };
8503 template<>
8504 template<>
8505 struct S<int>::M<char> //#1
8506 {
8507 int i;
8508 };
8509 [temp.expl.spec]/4 says this is valid.
8511 In this case, when we write:
8512 S<int>::M<char> m;
8514 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
8515 the one of #0.
8517 When we encounter #1, we want to store the partial instantiation
8518 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
8520 For all cases other than this "explicit specialization of member of a
8521 class template", we just want to store the most general template into
8522 the CLASSTYPE_TI_TEMPLATE of M.
8524 This case of "explicit specialization of member of a class template"
8525 only happens when:
8526 1/ the enclosing class is an instantiation of, and therefore not
8527 the same as, the context of the most general template, and
8528 2/ we aren't looking at the partial instantiation itself, i.e.
8529 the innermost arguments are not the same as the innermost parms of
8530 the most general template.
8532 So it's only when 1/ and 2/ happens that we want to use the partial
8533 instantiation of the member template in lieu of its most general
8534 template. */
8538 /* the enclosing class must be an instantiation... */
8541 {
8542 tree partial_inst_args;
8545 partial_inst_args =
8551 use_partial_inst_tmpl =
8552 /*...and we must not be looking at the partial instantiation
8553 itself. */
8555 partial_inst_args);
8556 }
8559 /* This case is easy; there are no member templates involved. */
8561 else
8562 {
8563 /* This is a full instantiation of a member template. Find
8564 the partial instantiation of which this is an instance. */
8566 /* Temporarily reduce by one the number of levels in the ARGLIST
8567 so as to avoid comparing the last set of arguments. */
8571 /* FOUND is either a proper class type, or an alias
8572 template specialization. In the later case, it's a
8573 TYPE_DECL, resulting from the substituting of arguments
8574 for parameters in the TYPE_DECL of the alias template
8575 done earlier. So be careful while getting the template
8576 of FOUND. */
8580 }
8582 // Build template info for the new specialization.
8591 /* Note this use of the partial instantiation so we can check it
8592 later in maybe_process_partial_specialization. */
8599 /* Now that the type has been registered on the instantiations
8600 list, we set up the enumerators. Because the enumeration
8601 constants may involve the enumeration type itself, we make
8602 sure to register the type first, and then create the
8603 constants. That way, doing tsubst_expr for the enumeration
8604 constants won't result in recursive calls here; we'll find
8605 the instantiation and exit above. */
8609 /* If the type makes use of template parameters, the
8610 code that generates debugging information will crash. */
8613 /* Possibly limit visibility based on template args. */
8620 }
8621 }
8623 /* Wrapper for lookup_template_class_1. */
8625 tree
8628 {
8629 tree ret;
8635 }
8637 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
8639 tree
8641 {
8642 /* The type of the expression is NULL_TREE since the template-id could refer
8643 to an explicit or partial specialization. */
8646 /* Except that concepts are always bool. */
8649 }
8651 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
8653 tree
8655 {
8659 /* We never want to return a VAR_DECL for a variable concept, since they
8660 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
8674 {
8676 {
8679 }
8681 }
8683 /* If a template-id refers to a specialization of a variable
8684 concept, then the expression is true if and only if the
8685 concept's constraints are satisfied by the given template
8686 arguments.
8688 NOTE: This is an extension of Concepts Lite TS that
8689 allows constraints to be used in expressions. */
8691 {
8694 }
8697 }
8698 \f
8699 struct pair_fn_data
8700 {
8701 tree_fn_t fn;
8703 /* True when we should also visit template parameters that occur in
8704 non-deduced contexts. */
8707 };
8709 /* Called from for_each_template_parm via walk_tree. */
8711 static tree
8713 {
8720 #define WALK_SUBTREE(NODE) \
8721 do \
8722 { \
8723 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
8724 pfd->include_nondeduced_p); \
8725 if (result) goto out; \
8726 } \
8727 while (0)
8734 {
8738 /* Fall through. */
8744 else
8754 /* Since we're not going to walk subtrees, we have to do this
8755 explicitly here. */
8757 /* Fall through. */
8760 /* Check the return type. */
8763 /* Check the parameter types. Since default arguments are not
8764 instantiated until they are needed, the TYPE_ARG_TYPES may
8765 contain expressions that involve template parameters. But,
8766 no-one should be looking at them yet. And, once they're
8767 instantiated, they don't contain template parameters, so
8768 there's no point in looking at them then, either. */
8769 {
8770 tree parm;
8775 /* Since we've already handled the TYPE_ARG_TYPES, we don't
8776 want walk_tree walking into them itself. */
8778 }
8794 /* Fall through. */
8806 /* Record template parameters such as `T' inside `TT<T>'. */
8808 /* Fall through. */
8820 /* A template template parameter is encountered. */
8824 /* Already substituted template template parameter */
8841 /* If there's no type, then this thing must be some expression
8842 involving template parameters. */
8864 }
8866 #undef WALK_SUBTREE
8868 /* We didn't find any template parameters we liked. */
8869 out:
8871 }
8873 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
8874 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
8875 call FN with the parameter and the DATA.
8876 If FN returns nonzero, the iteration is terminated, and
8877 for_each_template_parm returns 1. Otherwise, the iteration
8878 continues. If FN never returns a nonzero value, the value
8879 returned by for_each_template_parm is 0. If FN is NULL, it is
8880 considered to be the function which always returns 1.
8882 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
8883 parameters that occur in non-deduced contexts. When false, only
8884 visits those template parameters that can be deduced. */
8886 static tree
8890 {
8892 tree result;
8894 /* Set up. */
8899 /* Walk the tree. (Conceptually, we would like to walk without
8900 duplicates, but for_each_template_parm_r recursively calls
8901 for_each_template_parm, so we would need to reorganize a fair
8902 bit to use walk_tree_without_duplicates, so we keep our own
8903 visited list.) */
8906 else
8909 for_each_template_parm_r,
8913 /* Clean up. */
8915 {
8918 }
8921 }
8923 /* Returns true if T depends on any template parameter. */
8925 int
8927 {
8957 else
8958 {
8961 }
8966 }
8968 /* Returns true iff current_function_decl is an incompletely instantiated
8969 template. Useful instead of processing_template_decl because the latter
8970 is set to 0 during instantiate_non_dependent_expr. */
8972 bool
8974 {
8983 }
8985 /* Returns true if T depends on any template parameter with level LEVEL. */
8987 bool
8989 {
8992 }
8994 /* Returns TRUE iff INST is an instantiation we don't need to do in an
8995 ill-formed translation unit, i.e. a variable or function that isn't
8996 usable in a constant expression. */
9000 {
9004 }
9006 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9007 neglectable and instantiated from within an erroneous instantiation. */
9009 static bool
9011 {
9022 }
9030 /* We're starting to instantiate D; record the template instantiation context
9031 for diagnostics and to restore it later. */
9033 bool
9035 {
9037 }
9039 /* We're starting to instantiate D; record the template instantiation context
9040 at LOC for diagnostics and to restore it later. */
9042 bool
9044 {
9048 {
9050 "template instantiation depth exceeds maximum of %d"
9052 max_tinst_depth);
9054 }
9056 /* If the current instantiation caused problems, don't let it instantiate
9057 anything else. Do allow deduction substitution and decls usable in
9058 constant expressions. */
9075 }
9077 /* We're done instantiating this template; return to the instantiation
9078 context. */
9080 void
9082 {
9083 /* Restore the filename and line number stashed away when we started
9084 this instantiation. */
9088 }
9090 /* We're instantiating a deferred template; restore the template
9091 instantiation context in which the instantiation was requested, which
9092 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9094 static tree
9096 {
9108 }
9110 /* Returns the TINST_LEVEL which gives the original instantiation
9111 context. */
9115 {
9121 }
9123 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9124 vector of template arguments, as for tsubst.
9126 Returns an appropriate tsubst'd friend declaration. */
9128 static tree
9130 {
9131 tree new_friend;
9136 /* This was a friend declared with an explicit template
9137 argument list, e.g.:
9139 friend void f<>(T);
9141 to indicate that f was a template instantiation, not a new
9142 function declaration. Now, we have to figure out what
9143 instantiation of what template. */
9144 {
9146 tree new_args;
9147 tree tmpl;
9150 /* Friend functions are looked up in the containing namespace scope.
9151 We must enter that scope, to avoid finding member functions of the
9152 current class with same name. */
9167 tsk_none);
9169 }
9173 /* The NEW_FRIEND will look like an instantiation, to the
9174 compiler, but is not an instantiation from the point of view of
9175 the language. For example, we might have had:
9177 template <class T> struct S {
9178 template <class U> friend void f(T, U);
9179 };
9181 Then, in S<int>, template <class U> void f(int, U) is not an
9182 instantiation of anything. */
9188 {
9192 }
9194 /* The mangled name for the NEW_FRIEND is incorrect. The function
9195 is not a template instantiation and should not be mangled like
9196 one. Therefore, we forget the mangling here; we'll recompute it
9197 later if we need it. */
9199 {
9202 }
9205 {
9206 tree old_decl;
9207 tree new_friend_template_info;
9208 tree new_friend_result_template_info;
9209 tree ns;
9212 /* We must save some information from NEW_FRIEND before calling
9213 duplicate decls since that function will free NEW_FRIEND if
9214 possible. */
9216 new_friend_is_defn =
9221 {
9222 /* This declaration is a `primary' template. */
9225 new_friend_result_template_info
9227 }
9228 else
9231 /* Make the init_value nonzero so pushdecl knows this is a defn. */
9235 /* Inside pushdecl_namespace_level, we will push into the
9236 current namespace. However, the friend function should go
9237 into the namespace of the template. */
9247 {
9248 /* This new friend declaration matched an existing
9249 declaration. For example, given:
9251 template <class T> void f(T);
9252 template <class U> class C {
9253 template <class T> friend void f(T) {}
9254 };
9256 the friend declaration actually provides the definition
9257 of `f', once C has been instantiated for some type. So,
9258 old_decl will be the out-of-class template declaration,
9259 while new_friend is the in-class definition.
9261 But, if `f' was called before this point, the
9262 instantiation of `f' will have DECL_TI_ARGS corresponding
9263 to `T' but not to `U', references to which might appear
9264 in the definition of `f'. Previously, the most general
9265 template for an instantiation of `f' was the out-of-class
9266 version; now it is the in-class version. Therefore, we
9267 run through all specialization of `f', adding to their
9268 DECL_TI_ARGS appropriately. In particular, they need a
9269 new set of outer arguments, corresponding to the
9270 arguments for this class instantiation.
9272 The same situation can arise with something like this:
9274 friend void f(int);
9275 template <class T> class C {
9276 friend void f(T) {}
9277 };
9279 when `C<int>' is instantiated. Now, `f(int)' is defined
9280 in the class. */
9283 /* On the other hand, if the in-class declaration does
9284 *not* provide a definition, then we don't want to alter
9285 existing definitions. We can just leave everything
9286 alone. */
9287 ;
9288 else
9289 {
9293 /* Overwrite whatever template info was there before, if
9294 any, with the new template information pertaining to
9295 the declaration. */
9299 {
9300 /* We should have called reregister_specialization in
9301 duplicate_decls. */
9306 /* Instantiate it if the global has already been used. */
9310 }
9311 else
9312 {
9313 tree t;
9315 /* Indicate that the old function template is a partial
9316 instantiation. */
9324 /* Reassign any specializations already in the hash table
9325 to the new more general template, and add the
9326 additional template args. */
9330 {
9332 spec_entry elt;
9344 register_specialization
9347 }
9349 }
9350 }
9352 /* The information from NEW_FRIEND has been merged into OLD_DECL
9353 by duplicate_decls. */
9355 }
9356 }
9357 else
9358 {
9362 /* In the code
9363 template <class T> class C {
9364 template <class U> friend void C1<U>::f (); // case 1
9365 friend void C2<T>::f (); // case 2
9366 };
9367 we only need to make sure CONTEXT is a complete type for
9368 case 2. To distinguish between the two cases, we note that
9369 CONTEXT of case 1 remains dependent type after tsubst while
9370 this isn't true for case 2. */
9380 {
9382 /* do_friend adds the TEMPLATE_DECL for any member friend
9383 template even if it isn't a member template, i.e.
9384 template <class T> friend A<T>::f();
9385 Look through it in that case. */
9389 /* Check to see that the declaration is really present, and,
9390 possibly obtain an improved declaration. */
9395 }
9396 }
9399 }
9401 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
9402 template arguments, as for tsubst.
9404 Returns an appropriate tsubst'd friend type or error_mark_node on
9405 failure. */
9407 static tree
9409 {
9410 tree friend_type;
9411 tree tmpl;
9412 tree context;
9415 {
9418 }
9423 {
9426 else
9428 }
9430 /* Look for a class template declaration. We look for hidden names
9431 because two friend declarations of the same template are the
9432 same. For example, in:
9434 struct A {
9435 template <typename> friend class F;
9436 };
9437 template <typename> struct B {
9438 template <typename> friend class F;
9439 };
9441 both F templates are the same. */
9445 /* But, if we don't find one, it might be because we're in a
9446 situation like this:
9448 template <class T>
9449 struct S {
9450 template <class U>
9451 friend struct S;
9452 };
9454 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
9455 for `S<int>', not the TEMPLATE_DECL. */
9457 {
9460 }
9463 {
9464 /* The friend template has already been declared. Just
9465 check to see that the declarations match, and install any new
9466 default parameters. We must tsubst the default parameters,
9467 of course. We only need the innermost template parameters
9468 because that is all that redeclare_class_template will look
9469 at. */
9472 {
9473 tree parms;
9474 location_t saved_input_location;
9484 }
9487 }
9488 else
9489 {
9490 /* The friend template has not already been declared. In this
9491 case, the instantiation of the template class will cause the
9492 injection of this template into the global scope. */
9497 /* The new TMPL is not an instantiation of anything, so we
9498 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
9499 the new type because that is supposed to be the corresponding
9500 template decl, i.e., TMPL. */
9507 /* Inject this template into the global scope. */
9509 }
9512 {
9515 else
9517 }
9520 }
9522 /* Returns zero if TYPE cannot be completed later due to circularity.
9523 Otherwise returns one. */
9525 static int
9527 {
9537 else
9539 }
9543 /* Apply any attributes which had to be deferred until instantiation
9544 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
9545 ARGS, COMPLAIN, IN_DECL are as tsubst. */
9547 static void
9550 {
9552 tree t;
9557 {
9561 }
9564 {
9568 }
9569 else
9573 {
9578 {
9581 {
9588 {
9595 clauses
9599 else
9601 }
9602 /* If the first attribute argument is an identifier, don't
9603 pass it through tsubst. Attributes like mode, format,
9604 cleanup and several target specific attributes expect it
9605 unmodified. */
9608 {
9609 tree chain
9611 in_decl,
9616 chain);
9617 }
9619 {
9620 /* An attribute pack expansion. */
9622 tree pack = (tsubst_pack_expansion
9626 {
9630 }
9632 }
9633 else
9639 }
9640 else
9642 }
9645 }
9646 }
9648 /* Perform (or defer) access check for typedefs that were referenced
9649 from within the template TMPL code.
9650 This is a subroutine of instantiate_decl and instantiate_class_template.
9651 TMPL is the template to consider and TARGS is the list of arguments of
9652 that template. */
9654 static void
9656 {
9657 location_t saved_location;
9668 {
9680 /* Make access check error messages point to the location
9681 of the use of the typedef. */
9685 tf_warning_or_error);
9686 }
9688 }
9690 static tree
9692 {
9694 tree typedecl;
9695 tree pbinfo;
9696 tree base_list;
9698 tree fn_context;
9707 /* Figure out which template is being instantiated. */
9711 /* Determine what specialization of the original template to
9712 instantiate. */
9715 {
9718 }
9720 {
9721 /* This TYPE is actually an instantiation of a partial
9722 specialization. We replace the innermost set of ARGS with
9723 the arguments appropriate for substitution. For example,
9724 given:
9726 template <class T> struct S {};
9727 template <class T> struct S<T*> {};
9729 and supposing that we are instantiating S<int*>, ARGS will
9730 presently be {int*} -- but we need {int}. */
9733 }
9734 else
9735 {
9738 }
9740 /* If the template we're instantiating is incomplete, then clearly
9741 there's nothing we can do. */
9745 /* If we've recursively instantiated too many templates, stop. */
9749 /* Now we're really doing the instantiation. Mark the type as in
9750 the process of being defined. */
9753 /* We may be in the middle of deferred access check. Disable
9754 it now. */
9761 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
9766 else
9767 {
9770 }
9771 /* Use #pragma pack from the template context. */
9777 /* Set the input location to the most specialized template definition.
9778 This is needed if tsubsting causes an error. */
9790 {
9793 /* Adjust visibility for template arguments. */
9795 }
9801 /* We should never instantiate a nested class before its enclosing
9802 class; we need to look up the nested class by name before we can
9803 instantiate it, and that lookup should instantiate the enclosing
9804 class. */
9810 {
9811 tree pbase_binfo;
9812 tree pushed_scope;
9815 /* We must enter the scope containing the type, as that is where
9816 the accessibility of types named in dependent bases are
9817 looked up from. */
9820 /* Substitute into each of the bases to determine the actual
9821 basetypes. */
9823 {
9824 tree base;
9830 {
9831 expanded_bases =
9838 }
9841 {
9843 /* Extract the already-expanded base class. */
9845 else
9846 /* Substitute to figure out the base class. */
9848 NULL_TREE);
9856 }
9857 }
9859 /* The list is now in reverse order; correct that. */
9864 }
9865 /* Now call xref_basetypes to set up all the base-class
9866 information. */
9874 /* Now that our base classes are set up, enter the scope of the
9875 class, so that name lookups into base classes, etc. will work
9876 correctly. This is precisely analogous to what we do in
9877 begin_class_definition when defining an ordinary non-template
9878 class, except we also need to push the enclosing classes. */
9881 /* Now members are processed in the order of declaration. */
9884 {
9888 {
9890 {
9891 /* Build new CLASSTYPE_NESTED_UTDS. */
9893 tree newtag;
9899 /* If the member is a class template, then -- even after
9900 substitution -- there may be dependent types in the
9901 template argument list for the class. We increment
9902 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
9903 that function will assume that no types are dependent
9904 when outside of a template. */
9914 {
9918 /* Unfortunately, lookup_template_class sets
9919 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
9920 instantiation (i.e., for the type of a member
9921 template class nested within a template class.)
9922 This behavior is required for
9923 maybe_process_partial_specialization to work
9924 correctly, but is not accurate in this case;
9925 the TAG is not an instantiation of anything.
9926 (The corresponding TEMPLATE_DECL is an
9927 instantiation, but the TYPE is not.) */
9930 /* Now, we call pushtag to put this NEWTAG into the scope of
9931 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
9932 pushtag calling push_template_decl. We don't have to do
9933 this for enums because it will already have been done in
9934 tsubst_enum. */
9938 }
9939 }
9941 {
9942 /* Build new TYPE_METHODS. */
9943 tree r;
9952 /* Instantiate members marked with attribute used. */
9958 }
9961 /* A closure type for a lambda in a default argument for a
9962 member template. Ignore it; it will be instantiated with
9964 else
9965 {
9966 /* Build new TYPE_FIELDS. */
9968 {
9969 tree condition;
9972 condition =
9982 }
9984 {
9985 tree r;
9989 /* The file and line for this declaration, to
9990 assist in error message reporting. Since we
9991 called push_tinst_level above, we don't need to
9992 restore these. */
10002 {
10003 /* A capture pack became multiple fields. */
10006 }
10009 {
10013 {
10014 /* In [temp.inst]:
10016 [t]he initialization (and any associated
10017 side-effects) of a static data member does
10018 not occur unless the static data member is
10019 itself used in a way that requires the
10020 definition of the static data member to
10021 exist.
10023 Therefore, we do not substitute into the
10024 initialized for the static data member here. */
10025 finish_static_data_member_decl
10031 /* Instantiate members marked with attribute used. */
10034 }
10036 {
10037 /* Determine whether R has a valid type and can be
10038 completed later. If R is invalid, then its type
10039 is replaced by error_mark_node. */
10048 {
10049 /* Flexible array mmembers of elements
10050 of complete type have an incomplete type
10051 and that's okay. */
10052 }
10054 {
10057 }
10058 }
10060 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10061 such a thing will already have been added to the field
10062 list by tsubst_enum in finish_member_declaration in the
10063 CLASSTYPE_NESTED_UTDS case above. */
10067 {
10070 }
10071 }
10072 }
10073 }
10074 }
10075 else
10076 {
10079 {
10080 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10086 {
10087 /* template <class T> friend class C; */
10090 }
10092 {
10093 /* template <class T> friend class C::D; */
10099 }
10102 {
10103 /* This could be either
10105 friend class T::C;
10107 when dependent_type_p is false or
10109 template <class U> friend class T::C;
10111 otherwise. */
10114 /* Bump processing_template_decl for correct
10115 dependent_type_p calculation. */
10120 }
10123 {
10124 /* friend class C;
10126 where C hasn't been declared yet. Let's lookup name
10127 from namespace scope directly, bypassing any name that
10128 come from dependent base class. */
10131 /* The call to xref_tag_from_type does injection for friend
10132 classes. */
10134 friend_type =
10138 }
10140 /* friend class C<T>; */
10143 /* Otherwise it's
10145 friend class C;
10147 where C is already declared or
10149 friend class C<int>;
10151 We don't have to do anything in these cases. */
10154 /* Trick make_friend_class into realizing that the friend
10155 we're adding is a template, not an ordinary class. It's
10156 important that we use make_friend_class since it will
10157 perform some error-checking and output cross-reference
10158 information. */
10166 }
10167 else
10168 {
10169 /* Build new DECL_FRIENDLIST. */
10170 tree r;
10172 /* The file and line for this declaration, to
10173 assist in error message reporting. Since we
10174 called push_tinst_level above, we don't need to
10175 restore these. */
10179 {
10182 }
10187 {
10190 }
10191 }
10192 }
10193 }
10196 {
10197 /* Restore these before substituting into the lambda capture
10198 initializers. */
10201 }
10204 {
10207 {
10210 {
10211 /* Set function_depth to avoid garbage collection. */
10215 }
10217 /* We need to instantiate the capture list from the template
10218 after we've instantiated the closure members, but before we
10219 consider adding the conversion op. Also keep any captures
10220 that may have been added during instantiation of the op(). */
10222 tree tmpl_cap
10231 }
10232 else
10234 }
10236 /* Set the file and line number information to whatever is given for
10237 the class itself. This puts error messages involving generated
10238 implicit functions at a predictable point, and the same point
10239 that would be used for non-template classes. */
10246 /* We don't instantiate default arguments for member functions. 14.7.1:
10248 The implicit instantiation of a class template specialization causes
10249 the implicit instantiation of the declarations, but not of the
10250 definitions or default arguments, of the class member functions,
10251 member classes, static data members and member templates.... */
10253 /* Some typedefs referenced from within the template code need to be access
10254 checked at template instantiation time, i.e now. These types were
10255 added to the template at parsing time. Let's get those and perform
10256 the access checks then. */
10266 /* The vtable for a template class can be emitted in any translation
10267 unit in which the class is instantiated. When there is no key
10268 method, however, finish_struct_1 will already have added TYPE to
10269 the keyed_classes list. */
10274 }
10276 /* Wrapper for instantiate_class_template_1. */
10278 tree
10280 {
10281 tree ret;
10286 }
10288 static tree
10290 {
10291 tree r;
10297 else
10298 {
10305 }
10307 }
10309 /* Given a function parameter pack TMPL_PARM and some function parameters
10310 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10311 and set *SPEC_P to point at the next point in the list. */
10313 tree
10315 {
10316 /* Collect all of the extra "packed" parameters into an
10317 argument pack. */
10318 tree parmvec;
10319 tree parmtypevec;
10330 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10335 {
10338 }
10340 /* Build the argument packs. */
10347 }
10349 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10350 NONTYPE_ARGUMENT_PACK. */
10352 static tree
10354 {
10356 }
10358 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10359 pack expansion with no extra args, 2 if it has extra args, or 0
10360 if it is not a pack expansion. */
10362 static int
10364 {
10370 /* A decl pack is itself an expansion. */
10377 }
10380 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
10382 static tree
10384 {
10391 }
10393 /* This is a subroutine of tsubst_pack_expansion.
10395 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
10396 mechanism to store the (non complete list of) arguments of the
10397 substitution and return a non substituted pack expansion, in order
10398 to wait for when we have enough arguments to really perform the
10399 substitution. */
10401 static bool
10405 {
10406 /* If one pack has an expansion and another pack has a normal
10407 argument or if one pack has an empty argument and an another
10408 one hasn't then tsubst_pack_expansion cannot perform the
10409 substitution and need to fall back on the
10410 PACK_EXPANSION_EXTRA mechanism. */
10418 {
10421 parm_pack;
10423 {
10428 /* We can't substitute a pack expansion with extra args into
10429 our pattern. */
10433 else
10435 }
10439 }
10441 }
10443 /* [temp.variadic]/6 says that:
10445 The instantiation of a pack expansion [...]
10446 produces a list E1,E2, ..., En, where N is the number of elements
10447 in the pack expansion parameters.
10449 This subroutine of tsubst_pack_expansion produces one of these Ei.
10451 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
10452 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
10453 PATTERN, and each TREE_VALUE is its corresponding argument pack.
10454 INDEX is the index 'i' of the element Ei to produce. ARGS,
10455 COMPLAIN, and IN_DECL are the same parameters as for the
10456 tsubst_pack_expansion function.
10458 The function returns the resulting Ei upon successful completion,
10459 or error_mark_node.
10461 Note that this function possibly modifies the ARGS parameter, so
10462 it's the responsibility of the caller to restore it. */
10464 static tree
10466 tree parm_packs,
10468 tree args /* This parm gets
10470 tsubst_flags_t complain,
10471 tree in_decl)
10472 {
10473 tree t;
10476 /* For each parameter pack, change the substitution of the parameter
10477 pack to the ith argument in its argument pack, then expand the
10478 pattern. */
10480 {
10485 ith_elem_is_expansion |=
10488 /* Select the Ith argument from the pack. */
10491 {
10493 {
10498 }
10499 else
10501 }
10502 else
10503 {
10508 {
10510 /* Update the corresponding argument. */
10512 }
10513 else
10514 /* Re-use the ARGUMENT_PACK_SELECT. */
10516 }
10518 }
10520 /* Substitute into the PATTERN with the (possibly altered)
10521 arguments. */
10523 /* Expanding a fixed parameter pack from
10524 coerce_template_parameter_pack. */
10529 {
10532 else
10535 }
10539 else
10542 /* If the Ith argument pack element is a pack expansion, then
10543 the Ith element resulting from the substituting is going to
10544 be a pack expansion as well. */
10549 }
10551 /* When the unexpanded parameter pack in a fold expression expands to an empty
10552 sequence, the value of the expression is as follows; the program is
10553 ill-formed if the operator is not listed in this table.
10555 * 1
10556 + 0
10557 & -1
10558 | 0
10559 && true
10560 || false
10561 , void() */
10563 tree
10565 {
10569 {
10586 }
10592 }
10594 /* Given a fold-expression T and a current LEFT and RIGHT operand,
10595 form an expression that combines the two terms using the
10596 operator of T. */
10598 static tree
10600 {
10604 // Handle compound assignment operators.
10609 {
10619 complain);
10620 }
10621 }
10623 /* Substitute ARGS into the pack of a fold expression T. */
10627 {
10629 }
10631 /* Substitute ARGS into the pack of a fold expression T. */
10635 {
10637 }
10639 /* Expand a PACK of arguments into a grouped as left fold.
10640 Given a pack containing elements A0, A1, ..., An and an
10641 operator @, this builds the expression:
10643 ((A0 @ A1) @ A2) ... @ An
10645 Note that PACK must not be empty.
10647 The operator is defined by the original fold expression T. */
10649 static tree
10651 {
10654 {
10657 }
10659 }
10661 /* Substitute into a unary left fold expression. */
10663 static tree
10665 tree in_decl)
10666 {
10672 else
10674 }
10676 /* Substitute into a binary left fold expression.
10678 Do ths by building a single (non-empty) vector of argumnts and
10679 building the expression from those elements. */
10681 static tree
10683 tree in_decl)
10684 {
10698 }
10700 /* Expand a PACK of arguments into a grouped as right fold.
10701 Given a pack containing elementns A0, A1, ..., and an
10702 operator @, this builds the expression:
10704 A0@ ... (An-2 @ (An-1 @ An))
10706 Note that PACK must not be empty.
10708 The operator is defined by the original fold expression T. */
10710 tree
10712 {
10713 // Build the expression.
10717 {
10720 }
10722 }
10724 /* Substitute into a unary right fold expression. */
10726 static tree
10728 tree in_decl)
10729 {
10735 else
10737 }
10739 /* Substitute into a binary right fold expression.
10741 Do ths by building a single (non-empty) vector of arguments and
10742 building the expression from those elements. */
10744 static tree
10746 tree in_decl)
10747 {
10762 }
10765 /* Substitute ARGS into T, which is an pack expansion
10766 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
10767 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
10768 (if only a partial substitution could be performed) or
10769 ERROR_MARK_NODE if there was an error. */
10770 tree
10772 tree in_decl)
10773 {
10774 tree pattern;
10778 tree result;
10786 /* Add in any args remembered from an earlier partial instantiation. */
10791 /* Determine the argument packs that will instantiate the parameter
10792 packs used in the expansion expression. While we're at it,
10793 compute the number of arguments to be expanded and make sure it
10794 is consistent. */
10797 {
10804 {
10808 else
10811 }
10813 {
10814 /* We know we have correct local_specializations if this
10815 expansion is at function scope, or if we're dealing with a
10816 local parameter in a requires expression; for the latter,
10817 tsubst_requires_expr set it up appropriately. */
10820 else
10821 /* We can't rely on local_specializations for a parameter
10822 name used later in a function declaration (such as in a
10823 late-specified return type). Even if it exists, it might
10824 have the wrong value for a recursive call. */
10828 {
10829 /* This parameter pack was used in an unevaluated context. Just
10830 make a dummy decl, since it's only used for its type. */
10833 /* Partial instantiation of the parm_pack, we can't build
10834 up an argument pack yet. */
10836 else
10838 }
10839 }
10842 else
10843 {
10849 }
10856 /* This can only happen if we forget to expand an argument
10857 pack somewhere else. Just return an error, silently. */
10858 {
10862 }
10865 {
10869 /* Don't bother trying to do a partial substitution with
10870 incomplete packs; we'll try again after deduction. */
10877 {
10883 pattern);
10884 else
10887 pattern);
10889 }
10891 /* Keep track of the parameter packs and their corresponding
10892 argument packs. */
10895 }
10896 else
10897 {
10898 /* We can't substitute for this parameter pack. We use a flag as
10899 well as the missing_level counter because function parameter
10900 packs don't have a level. */
10902 }
10903 }
10905 /* If the expansion is just T..., return the matching argument pack, unless
10906 we need to call convert_from_reference on all the elements. This is an
10907 important optimization; see c++/68422. */
10910 {
10912 /* Types need no adjustment, nor does sizeof..., and if we still have
10913 some pack expansion args we won't do anything yet. */
10918 /* Also optimize expression pack expansions if we can tell that the
10919 elements won't have reference type. */
10925 /* Otherwise use the normal path so we get convert_from_reference. */
10926 }
10928 /* We cannot expand this expansion expression, because we don't have
10929 all of the argument packs we need. */
10931 {
10932 /* We got some full packs, but we can't substitute them in until we
10933 have values for all the packs. So remember these until then. */
10938 }
10940 {
10941 /* There were no real arguments, we're just replacing a parameter
10942 pack with another version of itself. Substitute into the
10943 pattern and return a PACK_EXPANSION_*. The caller will need to
10944 deal with that. */
10948 else
10952 }
10957 {
10958 /* We're in a late-specified return type, so create our own local
10959 specializations map; the current map is either NULL or (in the
10960 case of recursive unification) might have bindings that we don't
10961 want to use or alter. */
10964 }
10966 /* For each argument in each argument pack, substitute into the
10967 pattern. */
10970 {
10972 i,
10974 in_decl);
10977 {
10980 }
10981 }
10983 /* Update ARGS to restore the substitution from parameter packs to
10984 their argument packs. */
10986 {
10992 else
10993 {
11001 /* Update the corresponding argument. */
11005 else
11007 }
11008 }
11011 {
11014 }
11017 }
11019 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11020 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11021 parameter packs; all parms generated from a function parameter pack will
11022 have the same DECL_PARM_INDEX. */
11024 tree
11026 {
11028 tree patparm;
11031 {
11037 }
11038 else
11039 {
11044 }
11047 }
11049 /* Substitute ARGS into the vector or list of template arguments T. */
11051 static tree
11053 {
11065 {
11067 tree new_arg;
11072 {
11073 /* Substitute into an expansion expression. */
11077 /* Add to the expanded length adjustment the number of
11078 expanded arguments. We subtract one from this
11079 measurement, because the argument pack expression
11080 itself is already counted as 1 in
11081 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11082 the argument pack is empty. */
11084 }
11086 {
11087 /* Substitute into each of the arguments. */
11093 new_arg,
11107 }
11108 }
11109 else
11118 }
11123 /* Make space for the expanded arguments coming from template
11124 argument packs. */
11126 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11127 arguments for a member template.
11128 In that case each TREE_VEC in ORIG_T represents a level of template
11129 arguments, and ORIG_T won't carry any non defaulted argument count.
11130 It will rather be the nested TREE_VECs that will carry one.
11131 In other words, ORIG_T carries a non defaulted argument count only
11132 if it doesn't contain any nested TREE_VEC. */
11134 {
11138 }
11140 {
11144 {
11147 /* Now expand the template argument pack "in place". */
11150 }
11151 else
11152 {
11154 out++;
11155 }
11156 }
11159 }
11161 /* Return the result of substituting ARGS into the template parameters
11162 given by PARMS. If there are m levels of ARGS and m + n levels of
11163 PARMS, then the result will contain n levels of PARMS. For
11164 example, if PARMS is `template <class T> template <class U>
11165 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11166 result will be `template <int*, double, class V>'. */
11168 static tree
11170 {
11174 /* When substituting into a template, we must set
11175 PROCESSING_TEMPLATE_DECL as the template parameters may be
11176 dependent if they are based on one-another, and the dependency
11177 predicates are short-circuit outside of templates. */
11184 {
11185 tree new_vec =
11190 {
11191 tree tuple;
11203 }
11209 }
11214 }
11216 /* Return the result of substituting ARGS into one template parameter
11217 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11218 parameter and which TREE_PURPOSE is the default argument of the
11219 template parameter. */
11221 static tree
11223 {
11244 }
11246 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11247 type T. If T is not an aggregate or enumeration type, it is
11248 handled as if by tsubst. IN_DECL is as for tsubst. If
11249 ENTERING_SCOPE is nonzero, T is the context for a template which
11250 we are presently tsubst'ing. Return the substituted value. */
11252 static tree
11254 tree args,
11255 tsubst_flags_t complain,
11256 tree in_decl,
11258 {
11263 {
11268 /* Else fall through. */
11272 {
11273 tree argvec;
11274 tree context;
11275 tree r;
11279 /* In "sizeof(X<I>)" we need to evaluate "I". */
11285 /* First, determine the context for the type we are looking
11286 up. */
11289 {
11292 /* If context is a nested class inside a class template,
11293 it may still need to be instantiated (c++/33959). */
11295 }
11297 /* Then, figure out what arguments are appropriate for the
11298 type we are trying to find. For example, given:
11300 template <class T> struct S;
11301 template <class T, class U> void f(T, U) { S<U> su; }
11303 and supposing that we are instantiating f<int, double>,
11304 then our ARGS will be {int, double}, but, when looking up
11305 S we only want {double}. */
11310 else
11311 {
11315 }
11321 }
11322 else
11323 /* This is not a template type, so there's nothing to do. */
11328 }
11329 }
11331 /* Substitute into the default argument ARG (a default argument for
11332 FN), which has the indicated TYPE. */
11334 tree
11336 {
11341 /* This can happen in invalid code. */
11345 /* This default argument came from a template. Instantiate the
11346 default argument here, not in tsubst. In the case of
11347 something like:
11349 template <class T>
11350 struct S {
11351 static T t();
11352 void f(T = t());
11353 };
11355 we must be careful to do name lookup in the scope of S<T>,
11356 rather than in the current class. */
11358 /* The "this" pointer is not valid in a default argument. */
11360 {
11365 }
11368 /* The default argument expression may cause implicitly defined
11369 member functions to be synthesized, which will result in garbage
11370 collection. We must treat this situation as if we were within
11371 the body of function so as to avoid collecting live data on the
11372 stack. */
11380 /* Restore the "this" pointer. */
11382 {
11385 }
11392 /* Make sure the default argument is reasonable. */
11398 }
11400 /* Substitute into all the default arguments for FN. */
11402 static void
11404 {
11405 tree arg;
11406 tree tmpl_args;
11410 /* If this function is not yet instantiated, we certainly don't need
11411 its default arguments. */
11414 /* Don't do this again for clones. */
11419 arg;
11425 complain);
11426 }
11428 /* Substitute the ARGS into the T, which is a _DECL. Return the
11429 result of the substitution. Issue error and warning messages under
11430 control of COMPLAIN. */
11432 static tree
11434 {
11435 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
11436 location_t saved_loc;
11441 /* Set the filename and linenumber to improve error-reporting. */
11446 {
11448 {
11449 /* We can get here when processing a member function template,
11450 member class template, or template template parameter. */
11452 tree spec;
11453 tree tmpl_args;
11454 tree full_args;
11457 {
11458 /* Template template parameter is treated here. */
11462 /* If we get a real template back, return it. This can happen in
11463 the context of most_specialized_partial_spec. */
11466 else
11467 /* The new TEMPLATE_DECL was built in
11468 reduce_template_parm_level. */
11471 }
11473 /* We might already have an instance of this template.
11474 The ARGS are for the surrounding class type, so the
11475 full args contain the tsubst'd args for the context,
11476 plus the innermost args from the template decl. */
11480 /* Because this is a template, the arguments will still be
11481 dependent, even after substitution. If
11482 PROCESSING_TEMPLATE_DECL is not set, the dependency
11483 predicates will short-circuit. */
11491 /* If this is a default template template argument,
11492 tsubst might not have changed anything. */
11499 {
11502 }
11504 /* Make a new template decl. It will be similar to the
11505 original, but will record the current template arguments.
11506 We also create a new function declaration, which is just
11507 like the old one, but points to this new template, rather
11508 than the old one. */
11513 // Build new template info linking to the original template decl.
11518 {
11519 tree new_type;
11527 /* For a partial specialization, we need to keep pointing to
11528 the primary template. */
11534 }
11535 else
11536 {
11537 tree new_decl;
11549 }
11555 /* The template parameters for this new template are all the
11556 template parameters for the old template, except the
11557 outermost level of parameters. */
11560 complain);
11566 /* Record this non-type partial instantiation. */
11570 }
11574 {
11575 tree ctx;
11578 tree gen_tmpl;
11579 tree type;
11584 /* Nobody should be tsubst'ing into non-template functions. */
11588 {
11589 tree spec;
11592 /* If T is not dependent, just return it. We have to
11593 increment PROCESSING_TEMPLATE_DECL because
11594 value_dependent_expression_p assumes that nothing is
11595 dependent when PROCESSING_TEMPLATE_DECL is zero. */
11602 /* Calculate the most general template of which R is a
11603 specialization, and the complete set of arguments used to
11604 specialize R. */
11607 (DECL_TEMPLATE_RESULT
11613 /* Check to see if we already have this specialization. */
11618 {
11621 }
11623 /* We can see more levels of arguments than parameters if
11624 there was a specialization of a member template, like
11625 this:
11627 template <class T> struct S { template <class U> void f(); }
11628 template <> template <class U> void S<int>::f(U);
11630 Here, we'll be substituting into the specialization,
11631 because that's where we can find the code we actually
11632 want to generate, but we'll have enough arguments for
11633 the most general template.
11635 We also deal with the peculiar case:
11637 template <class T> struct S {
11638 template <class U> friend void f();
11639 };
11640 template <class U> void f() {}
11641 template S<int>;
11642 template void f<double>();
11644 Here, the ARGS for the instantiation of will be {int,
11645 double}. But, we only need as many ARGS as there are
11646 levels of template parameters in CODE_PATTERN. We are
11647 careful not to get fooled into reducing the ARGS in
11648 situations like:
11650 template <class T> struct S { template <class U> void f(U); }
11651 template <class T> template <> void S<T>::f(int) {}
11653 which we can spot because the pattern will be a
11654 specialization in this case. */
11656 parms_depth =
11661 }
11662 else
11663 {
11664 /* This special case arises when we have something like this:
11666 template <class T> struct S {
11667 friend void f<int>(int, double);
11668 };
11670 Here, the DECL_TI_TEMPLATE for the friend declaration
11671 will be an IDENTIFIER_NODE. We are being called from
11672 tsubst_friend_function, and we want only to create a
11673 new decl (R) with appropriate types so that we can call
11674 determine_specialization. */
11676 }
11679 {
11682 else
11686 }
11687 else
11688 {
11691 }
11696 /* If we hit excessive deduction depth, the type is bogus even if
11697 it isn't error_mark_node, so don't build a decl. */
11701 /* We do NOT check for matching decls pushed separately at this
11702 point, as they may not represent instantiations of this
11703 template, and in any case are considered separate under the
11704 discrete model. */
11708 /* Clear out the mangled name and RTL for the instantiation. */
11711 /* Leave DECL_INITIAL set on deleted instantiations. */
11716 /* OpenMP UDRs have the only argument a reference to the declared
11717 type. We want to diagnose if the declared type is a reference,
11718 which is invalid, but as references to references are usually
11719 quietly merged, diagnose it here. */
11721 {
11722 tree argtype
11727 "reference type %qT in "
11731 argtype);
11732 }
11735 /* Type-conversion operator. Reconstruct the name, in
11736 case it's the name of one of the template's parameters. */
11746 /* If this is an instantiation of a function with internal
11747 linkage, we already know what object file linkage will be
11748 assigned to the instantiation. */
11757 /* We'll re-clone as appropriate in instantiate_template. */
11760 /* If we aren't complaining now, return on error before we register
11761 the specialization so that we'll complain eventually. */
11767 /* When instantiating a constrained member, substitute
11768 into the constraints to create a new constraint. */
11771 {
11774 }
11776 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
11777 this in the special friend case mentioned above where
11778 GEN_TMPL is NULL. */
11780 {
11785 tree new_r
11788 /* We instantiated this while substituting into
11789 the type earlier (template/friend54.C). */
11792 /* We're not supposed to instantiate default arguments
11793 until they are called, for a template. But, for a
11794 declaration like:
11796 template <class T> void f ()
11797 { extern void g(int i = T()); }
11799 we should do the substitution when the template is
11800 instantiated. We handle the member function case in
11801 instantiate_class_template since the default arguments
11802 might refer to other members of the class. */
11807 }
11808 else
11811 /* Copy the list of befriending classes. */
11815 {
11819 in_decl);
11820 }
11823 {
11829 /* If this is an instantiation of a member template, clone it.
11830 If it isn't, that'll be handled by
11831 clone_constructors_and_destructors. */
11834 }
11845 /* Possibly limit visibility based on template args. */
11848 {
11852 }
11860 }
11864 {
11872 {
11873 /* If there is a local specialization that isn't a
11874 parameter pack, it means that we're doing a "simple"
11875 substitution from inside tsubst_pack_expansion. Just
11876 return the local specialization (which will be a single
11877 parm). */
11884 /* Expand the TYPE_PACK_EXPANSION that provides the types for
11885 the parameters in this function parameter pack. */
11889 {
11892 /* Zero-length parameter packs are boring. Just substitute
11893 into the chain. */
11897 }
11898 else
11899 {
11900 /* All we did was update the type. Make a note of that. */
11903 }
11904 }
11906 /* Loop through all of the parameters we'll build. When T is
11907 a function parameter pack, LEN is the number of expanded
11908 types in EXPANDED_TYPES; otherwise, LEN is 1. */
11911 {
11918 /* We're on the Ith parameter of the function parameter
11919 pack. */
11920 {
11921 /* Get the Ith type. */
11924 /* Rename the parameter to include the index. */
11927 }
11929 /* We're dealing with a normal parameter. */
11937 {
11940 else
11943 }
11953 /* Keep track of the first new parameter we
11954 generate. That's what will be returned to the
11955 caller. */
11959 /* Build a proper chain of parameters when substituting
11960 into a function parameter pack. */
11963 }
11965 /* If cp_unevaluated_operand is set, we're just looking for a
11966 single dummy parameter, so don't keep going. */
11971 /* FIRST_R contains the start of the chain we've built. */
11973 }
11977 {
11984 {
11985 /* This field is a lambda capture pack. Return a TREE_VEC of
11986 the expanded fields to instantiate_class_template_1 and
11987 store them in the specializations hash table as a
11988 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
11992 {
11995 }
11996 else
11997 {
11998 /* All we did was update the type. Make a note of that. */
12001 }
12002 }
12005 {
12008 {
12012 }
12022 /* For bit-fields, DECL_INITIAL gives the number of bits. For
12023 non-bit-fields DECL_INITIAL is a non-static data member
12024 initializer, which gets deferred instantiation. */
12030 {
12031 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12032 NSDMI in perform_member_init. Still set DECL_INITIAL
12033 so that we know there is one. */
12038 }
12039 /* We don't have to set DECL_CONTEXT here; it is set by
12040 finish_member_declaration. */
12048 }
12051 {
12059 }
12060 }
12064 /* We reach here only for member using decls. We also need to check
12065 uses_template_parms because DECL_DEPENDENT_P is not set for a
12066 using-declaration that designates a member of the current
12067 instantiation (c++/53549). */
12070 {
12077 else
12078 {
12081 }
12082 }
12083 else
12084 {
12087 }
12092 {
12095 tree spec;
12097 tree ctx;
12106 {
12107 /* If this is the canonical decl, we don't have to
12108 mess with instantiations, and often we can't (for
12109 typename, template type parms and such). Note that
12110 TYPE_NAME is not correct for the above test if
12111 we've copied the type for a typedef. */
12117 }
12119 /* Check to see if we already have the specialization we
12120 need. */
12123 {
12124 /* T is a static data member or namespace-scope entity.
12125 We have to substitute into namespace-scope variables
12126 (not just variable templates) because of cases like:
12128 template <class T> void f() { extern T t; }
12130 where the entity referenced is not known until
12131 instantiation time. */
12135 {
12137 complain,
12139 /* If CTX is unchanged, then T is in fact the
12140 specialization we want. That situation occurs when
12141 referencing a static data member within in its own
12142 class. We can use pointer equality, rather than
12143 same_type_p, because DECL_CONTEXT is always
12144 canonical... */
12146 /* ... unless T is a member template; in which
12147 case our caller can be willing to create a
12148 specialization of that template represented
12149 by T. */
12153 }
12156 {
12161 argvec = (coerce_innermost_template_parms
12169 }
12170 }
12171 else
12172 {
12173 /* A local variable. */
12175 /* Subsequent calls to pushdecl will fill this in. */
12178 }
12179 /* If we already have the specialization we need, there is
12180 nothing more to do. */
12182 {
12185 }
12187 /* Create a new node for the specialization we need. */
12190 {
12193 else
12200 }
12202 {
12203 /* Even if the original location is out of scope, the
12204 newly substituted one is not. */
12211 {
12212 /* It may seem that this case cannot occur, since:
12214 typedef void f();
12215 void g() { f x; }
12217 declares a function, not a variable. However:
12219 typedef void f();
12220 template <typename T> void g() { T t; }
12221 template void g<f>();
12223 is an attempt to declare a variable with function
12224 type. */
12226 /* R is not yet sufficiently initialized, so we
12227 just use its name. */
12230 }
12232 /* Wait until cp_finish_decl to set this again, to handle
12233 circular dependency (template/instantiate6.C). */
12238 {
12243 {
12246 }
12248 }
12252 }
12258 /* Clear out the mangled name and RTL for the instantiation. */
12262 /* The initializer must not be expanded until it is required;
12263 see [temp.inst]. */
12269 {
12270 /* Possibly limit visibility based on template args. */
12273 {
12277 }
12279 }
12282 {
12283 /* A static data member declaration is always marked
12284 external when it is declared in-class, even if an
12285 initializer is present. We mimic the non-template
12286 processing here. */
12294 }
12295 else
12296 {
12301 }
12309 /* Preserve a typedef that names a type. */
12311 {
12315 /* An alias template specialization can be dependent
12316 even if its underlying type is not. */
12318 }
12321 }
12326 }
12327 #undef RETURN
12329 out:
12330 /* Restore the file and line information. */
12334 }
12336 /* Substitute into the ARG_TYPES of a function type.
12337 If END is a TREE_CHAIN, leave it and any following types
12338 un-substituted. */
12340 static tree
12342 tree args,
12343 tree end,
12344 tsubst_flags_t complain,
12345 tree in_decl)
12346 {
12347 tree remaining_arg_types;
12351 tree default_arg;
12362 {
12363 /* For a pack expansion, perform substitution on the
12364 entire expression. Later on, we'll handle the arguments
12365 one-by-one. */
12370 /* So that we'll spin through the parameters, one by one. */
12372 else
12373 {
12374 /* We only partially substituted into the parameter
12375 pack. Our type is TYPE_PACK_EXPANSION. */
12378 }
12379 }
12392 {
12394 {
12398 }
12400 }
12401 /* DR 657. */
12405 /* Do array-to-pointer, function-to-pointer conversion, and ignore
12406 top-level qualifiers as required. */
12409 /* We do not substitute into default arguments here. The standard
12410 mandates that they be instantiated only when needed, which is
12411 done in build_over_call. */
12415 {
12416 /* We've instantiated a template before its default arguments
12417 have been parsed. This can happen for a nested template
12418 class, and is not an error unless we require the default
12419 argument in a call of this function. */
12420 remaining_arg_types =
12423 }
12424 else
12425 remaining_arg_types =
12427 }
12430 }
12432 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
12433 *not* handle the exception-specification for FNTYPE, because the
12434 initial substitution of explicitly provided template parameters
12435 during argument deduction forbids substitution into the
12436 exception-specification:
12438 [temp.deduct]
12440 All references in the function type of the function template to the
12441 corresponding template parameters are replaced by the specified tem-
12442 plate argument values. If a substitution in a template parameter or
12443 in the function type of the function template results in an invalid
12444 type, type deduction fails. [Note: The equivalent substitution in
12445 exception specifications is done only when the function is instanti-
12446 ated, at which point a program is ill-formed if the substitution
12447 results in an invalid type.] */
12449 static tree
12451 tree args,
12452 tsubst_flags_t complain,
12453 tree in_decl)
12454 {
12455 tree return_type;
12457 tree fntype;
12459 /* The TYPE_CONTEXT is not used for function/method types. */
12462 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
12463 failure. */
12467 {
12468 /* Substitute the argument types. */
12480 {
12481 /* DR 1207: 'this' is in scope in the trailing return type. */
12483 }
12485 /* Substitute the return type. */
12489 {
12492 }
12493 }
12494 else
12495 /* Substitute the return type. */
12500 /* DR 486 clarifies that creation of a function type with an
12501 invalid return type is a deduction failure. */
12504 {
12506 {
12509 else
12511 }
12513 }
12514 /* And DR 657. */
12519 {
12520 /* Substitute the argument types. */
12525 }
12527 /* Construct a new type node and return it. */
12529 {
12534 }
12535 else
12536 {
12538 /* Don't pick up extra function qualifiers from the basetype. */
12541 {
12542 /* [temp.deduct]
12544 Type deduction may fail for any of the following
12545 reasons:
12547 -- Attempting to create "pointer to member of T" when T
12548 is not a class type. */
12551 r);
12553 }
12558 }
12565 }
12567 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
12568 ARGS into that specification, and return the substituted
12569 specification. If there is no specification, return NULL_TREE. */
12571 static tree
12573 tree args,
12574 tsubst_flags_t complain,
12575 tree in_decl,
12577 {
12578 tree specs;
12579 tree new_specs;
12584 {
12585 /* A noexcept-specifier. */
12590 {
12591 /* Defer instantiation of noexcept-specifiers to avoid
12592 excessive instantiations (c++/49107). */
12595 {
12596 /* We already partially instantiated this member template,
12597 so combine the new args with the old. */
12602 }
12603 else
12604 {
12607 }
12608 }
12609 else
12610 new_specs = tsubst_copy_and_build
12614 }
12616 {
12619 else
12621 {
12622 tree spec;
12627 {
12628 /* Expand the pack expansion type. */
12631 in_decl);
12637 else
12638 {
12639 /* We're substituting into a member template, so
12640 we got a TYPE_PACK_EXPANSION back. Add that
12641 expansion and move on. */
12645 expanded_specs,
12646 complain);
12649 }
12650 }
12653 {
12656 else
12661 complain);
12662 }
12665 }
12666 }
12668 }
12670 /* Take the tree structure T and replace template parameters used
12671 therein with the argument vector ARGS. IN_DECL is an associated
12672 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
12673 Issue error and warning messages under control of COMPLAIN. Note
12674 that we must be relatively non-tolerant of extensions here, in
12675 order to preserve conformance; if we allow substitutions that
12676 should not be allowed, we may allow argument deductions that should
12677 not succeed, and therefore report ambiguous overload situations
12678 where there are none. In theory, we could allow the substitution,
12679 but indicate that it should have failed, and allow our caller to
12680 make sure that the right thing happens, but we don't try to do this
12681 yet.
12683 This function is used for dealing with types, decls and the like;
12684 for expressions, use tsubst_expr or tsubst_copy. */
12686 tree
12688 {
12711 else
12716 /* Reuse typedefs. We need to do this to handle dependent attributes,
12717 such as attribute aligned. */
12720 {
12724 {
12725 /* DECL represents an alias template and we want to
12726 instantiate it. */
12730 }
12734 {
12738 }
12743 else
12744 /* The typedef is from a non-template context. */
12748 {
12750 r = cp_build_qualified_type_real
12754 }
12755 else
12756 {
12757 /* We don't have an instantiation yet, so drop the typedef. */
12762 }
12763 }
12776 {
12799 {
12805 }
12807 {
12813 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
12814 needed. */
12820 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
12821 with TREE_SIDE_EFFECTS that indicates this is not an integral
12822 constant expression. */
12825 {
12828 }
12831 }
12837 {
12843 /* Early in template argument deduction substitution, we don't
12844 want to reduce the level of 'auto', or it will be confused
12845 with a normal template parm in subsequent deduction. */
12857 {
12861 {
12862 /* See through ARGUMENT_PACK_SELECT arguments. */
12864 /* If the selected argument is an expansion E, that most
12865 likely means we were called from
12866 gen_elem_of_pack_expansion_instantiation during the
12867 substituting of pack an argument pack (which Ith
12868 element is a pack expansion, where I is
12869 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
12870 In this case, the Ith element resulting from this
12871 substituting is going to be a pack expansion, which
12872 pattern is the pattern of E. Let's return the
12873 pattern of E, and
12874 gen_elem_of_pack_expansion_instantiation will
12875 build the resulting pack expansion from it. */
12877 {
12878 /* Make sure we aren't throwing away arg info. */
12881 }
12882 }
12883 }
12888 {
12890 /* If ARG is an argument pack, we don't actually want to
12891 perform a substitution here, because substitutions
12892 for argument packs are only done
12893 element-by-element. We can get to this point when
12894 substituting the type of a non-type template
12895 parameter pack, when that type actually contains
12896 template parameter packs from an outer template, e.g.,
12898 template<typename... Types> struct A {
12899 template<Types... Values> struct B { };
12900 }; */
12904 {
12910 return cp_build_qualified_type_real
12912 }
12914 {
12915 /* We are processing a type constructed from a
12916 template template parameter. */
12927 /* Consider this code:
12929 template <template <class> class Template>
12930 struct Internal {
12931 template <class Arg> using Bind = Template<Arg>;
12932 };
12934 template <template <class> class Template, class Arg>
12935 using Instantiate = Template<Arg>; //#0
12937 template <template <class> class Template,
12938 class Argument>
12939 using Bind =
12940 Instantiate<Internal<Template>::template Bind,
12941 Argument>; //#1
12943 When #1 is parsed, the
12944 BOUND_TEMPLATE_TEMPLATE_PARM representing the
12945 parameter `Template' in #0 matches the
12946 UNBOUND_CLASS_TEMPLATE representing the argument
12947 `Internal<Template>::template Bind'; We then want
12948 to assemble the type `Bind<Argument>' that can't
12949 be fully created right now, because
12950 `Internal<Template>' not being complete, the Bind
12951 template cannot be looked up in that context. So
12952 we need to "store" `Bind<Argument>' for later
12953 when the context of Bind becomes complete. Let's
12954 store that in a TYPENAME_TYPE. */
12958 argvec),
12959 typename_type,
12960 complain);
12962 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
12963 are resolving nested-types in the signature of a
12964 member function templates. Otherwise ARG is a
12965 TEMPLATE_DECL and is the real template to be
12966 instantiated. */
12974 complain);
12975 return cp_build_qualified_type_real
12977 }
12978 else
12979 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
12981 }
12984 /* This can happen during the attempted tsubst'ing in
12985 unify. This means that we don't yet have any information
12986 about the template parameter in question. */
12989 /* If we get here, we must have been looking at a parm for a
12990 more deeply nested template. Make a new version of this
12991 template parameter, but with a lower level. */
12993 {
12998 {
13000 r = cp_build_qualified_type_real
13004 }
13011 /* Break infinite recursion when substituting the constraints
13013 else
13014 {
13024 /* Propagate constraints on placeholders. */
13031 /* We have reduced the level of the template
13032 template parameter, but not the levels of its
13033 template parameters, so canonical_type_parameter
13034 will not be able to find the canonical template
13035 template parameter for this level. Thus, we
13036 require structural equality checking to compare
13037 TEMPLATE_TEMPLATE_PARMs. */
13041 else
13045 {
13053 }
13054 }
13063 }
13066 }
13069 {
13077 {
13081 }
13084 {
13088 }
13091 {
13095 }
13101 }
13104 /* We should never be tsubsting a binfo. */
13108 /* A vector of template arguments. */
13114 {
13118 /* [temp.deduct]
13120 Type deduction may fail for any of the following
13121 reasons:
13123 -- Attempting to create a pointer to reference type.
13124 -- Attempting to create a reference to a reference type or
13125 a reference to void.
13127 Core issue 106 says that creating a reference to a reference
13128 during instantiation is no longer a cause for failure. We
13129 only enforce this check in strict C++98 mode. */
13133 {
13136 /* We keep track of the last time we issued this error
13137 message to avoid spewing a ton of messages during a
13138 single bad template instantiation. */
13141 {
13146 else
13149 }
13152 }
13156 {
13158 {
13161 type);
13162 else
13164 type);
13165 }
13167 }
13169 {
13173 }
13175 /* In C++0x, during template argument substitution, when there is an
13176 attempt to create a reference to a reference type, reference
13177 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
13179 "If a template-argument for a template-parameter T names a type
13180 that is a reference to a type A, an attempt to create the type
13181 'lvalue reference to cv T' creates the type 'lvalue reference to
13182 A,' while an attempt to create the type type rvalue reference to
13183 cv T' creates the type T"
13184 */
13185 r = cp_build_reference_type
13188 else
13193 /* Will this ever be needed for TYPE_..._TO values? */
13197 }
13199 {
13202 {
13203 /* [temp.deduct]
13205 Type deduction may fail for any of the following
13206 reasons:
13208 -- Attempting to create "pointer to member of T" when T
13209 is not a class type. */
13213 }
13215 {
13219 }
13221 {
13225 }
13228 {
13229 /* The type of the implicit object parameter gets its
13230 cv-qualifiers from the FUNCTION_TYPE. */
13231 tree memptr;
13232 tree method_type
13237 complain);
13238 }
13239 else
13242 complain);
13243 }
13246 {
13247 tree fntype;
13248 tree specs;
13253 /* Substitute the exception specification. */
13261 }
13263 {
13268 /* As an optimization, we avoid regenerating the array type if
13269 it will obviously be the same as T. */
13273 /* These checks should match the ones in create_array_type_for_decl.
13275 [temp.deduct]
13277 The deduction may fail for any of the following reasons:
13279 -- Attempting to create an array with an element type that
13280 is void, a function type, or a reference type, or [DR337]
13281 an abstract class type. */
13287 {
13291 }
13299 {
13302 }
13305 }
13308 {
13318 {
13322 }
13324 {
13325 /* Normally, make_typename_type does not require that the CTX
13326 have complete type in order to allow things like:
13328 template <class T> struct S { typename S<T>::X Y; };
13330 But, such constructs have already been resolved by this
13331 point, so here CTX really should have complete type, unless
13332 it's a partial instantiation. */
13335 {
13339 }
13340 }
13347 {
13350 }
13353 {
13355 {
13359 else
13361 }
13363 {
13367 else
13369 }
13370 }
13372 return cp_build_qualified_type_real
13374 }
13377 {
13389 }
13392 {
13393 tree type;
13409 complain);
13410 }
13413 {
13414 tree type;
13432 else
13433 {
13437 /* In a template ~id could be either a complement expression
13438 or an unqualified-id naming a destructor; if instantiating
13439 it produces an expression, it's not an id-expression or
13440 member access. */
13443 }
13448 }
13451 {
13455 }
13459 {
13461 tree packed_out =
13463 args,
13464 complain,
13465 in_decl);
13468 /* For template nontype argument packs, also substitute into
13469 the type. */
13474 }
13490 /* We should use one of the expression tsubsts for these codes. */
13496 }
13497 }
13499 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
13500 type of the expression on the left-hand side of the "." or "->"
13501 operator. */
13503 static tree
13506 {
13507 tree name;
13508 tree qualifying_scope;
13509 tree fns;
13510 tree optype;
13515 /* A baselink indicates a function from a base class. Both the
13516 BASELINK_ACCESS_BINFO and the base class referenced may
13517 indicate bases of the template class, rather than the
13518 instantiated class. In addition, lookups that were not
13519 ambiguous before may be ambiguous now. Therefore, we perform
13520 the lookup again. */
13527 {
13534 }
13542 /* If lookup found a single function, mark it as used at this
13543 point. (If it lookup found multiple functions the one selected
13544 later by overload resolution will be marked as used at that
13545 point.) */
13552 /* Add back the template arguments, if present. */
13557 template_args);
13558 /* Update the conversion operator type. */
13566 qualifying_scope,
13567 object_type);
13569 }
13571 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
13572 true if the qualified-id will be a postfix-expression in-and-of
13573 itself; false if more of the postfix-expression follows the
13574 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
13575 of "&". */
13577 static tree
13581 {
13582 tree expr;
13583 tree scope;
13584 tree name;
13586 tree template_args;
13591 /* Figure out what name to look up. */
13594 {
13602 }
13603 else
13604 {
13607 }
13609 /* Substitute into the qualifying scope. When there are no ARGS, we
13610 are just trying to simplify a non-dependent expression. In that
13611 case the qualifying scope may be dependent, and, in any case,
13612 substituting will not help. */
13615 {
13618 }
13619 else
13623 {
13628 }
13631 {
13633 {
13634 /* A BIT_NOT_EXPR is used to represent a destructor. */
13636 {
13640 }
13641 else
13644 }
13645 else
13649 {
13651 {
13655 }
13657 }
13658 }
13661 {
13663 scope);
13664 /* Remember that there was a reference to this entity. */
13667 }
13670 {
13676 }
13685 {
13686 expr = (adjust_result_of_qualified_name_lookup
13688 expr = (finish_qualified_id_expr
13692 }
13694 /* Expressions do not generally have reference type. */
13696 /* However, if we're about to form a pointer-to-member, we just
13697 want the referenced member referenced. */
13702 }
13704 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
13705 initializer, DECL is the substituted VAR_DECL. Other arguments are as
13706 for tsubst. */
13708 static tree
13711 {
13718 {
13719 /* If we had an initializer but it
13720 instantiated to nothing,
13721 value-initialize the object. This will
13722 only occur when the initializer was a
13723 pack expansion where the parameter packs
13724 used in that expansion were of length
13725 zero. */
13727 complain);
13730 }
13733 }
13735 /* Like tsubst, but deals with expressions. This function just replaces
13736 template parms; to finish processing the resultant expression, use
13737 tsubst_copy_and_build or tsubst_expr. */
13739 static tree
13741 {
13743 tree r;
13751 {
13756 {
13757 /* We get here for a use of 'this' in an NSDMI. */
13759 && current_function_decl
13763 /* This can happen for a parameter name used later in a function
13764 declaration (such as in a late-specified return type). Just
13765 make a dummy decl, since it's only used for its type. */
13768 /* Give it the template pattern as its context; its true context
13769 hasn't been instantiated yet and this is good enough for
13770 mangling. */
13772 }
13781 {
13782 tree enum_type;
13783 tree v;
13787 /* There is no need to substitute into namespace-scope
13788 enumerators. */
13791 /* If ARGS is NULL, then T is known to be non-dependent. */
13795 /* Unfortunately, we cannot just call lookup_name here.
13796 Consider:
13798 template <int I> int f() {
13799 enum E { a = I };
13800 struct S { void g() { E e = a; } };
13801 };
13803 When we instantiate f<7>::S::g(), say, lookup_name is not
13804 clever enough to find f<7>::a. */
13805 enum_type
13815 /* We didn't find the name. That should never happen; if
13816 name-lookup found it during preliminary parsing, we
13817 should find it again here during instantiation. */
13819 }
13824 {
13825 /* Check for a local specialization set up by
13826 tsubst_pack_expansion. */
13828 {
13832 }
13834 /* When retrieving a capture pack from a generic lambda, remove the
13835 lambda call op's own template argument list from ARGS. Only the
13836 template arguments active for the closure type should be used to
13837 retrieve the pack specialization. */
13843 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
13844 tsubst_decl put in the hash table. */
13846 }
13849 {
13850 tree ctx;
13855 {
13858 {
13862 }
13864 }
13865 }
13874 {
13877 {
13878 /* First try name lookup to find the instantiation. */
13881 {
13882 /* Make sure that the one we found is the one we want. */
13888 }
13892 else
13893 {
13894 /* This can happen for a variable used in a
13895 late-specified return type of a local lambda, or for a
13896 local static or constant. Building a new VAR_DECL
13897 should be OK in all those cases. */
13900 {
13901 /* We can't call cp_finish_decl, so handle the
13902 initializer by hand. */
13913 }
13918 {
13921 at_eof);
13922 else
13924 }
13925 }
13926 /* Remember this for subsequent uses. */
13929 }
13930 }
13931 else
13941 /* An OVERLOAD will always be a non-dependent overload set; an
13942 overload set from function scope will just be represented with an
13943 IDENTIFIER_NODE, and from class scope with a BASELINK. */
13959 {
13960 /* Template template argument like the following example need
13961 special treatment:
13963 template <template <class> class TT> struct C {};
13964 template <class T> struct D {
13965 template <class U> struct E {};
13966 C<E> c; // #1
13967 };
13968 D<int> d; // #2
13970 We are processing the template argument `E' in #1 for
13971 the template instantiation #2. Originally, `E' is a
13972 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
13973 have to substitute this with one having context `D<int>'. */
13977 }
13978 else
13979 /* Ordinary template template argument. */
13990 {
13994 }
13998 {
14007 /* We only want to compute the number of arguments. */
14021 {
14024 else
14030 else
14033 }
14034 else
14036 }
14038 {
14046 }
14047 /* Fall through */
14063 {
14067 }
14070 {
14071 tree object;
14072 tree name;
14077 {
14081 }
14084 {
14094 }
14099 in_decl);
14100 else
14103 }
14141 {
14145 }
14148 {
14153 }
14156 {
14160 }
14163 {
14171 }
14177 {
14184 }
14187 {
14194 }
14197 {
14204 }
14207 {
14208 /* Substituted template arguments */
14217 }
14220 {
14240 }
14265 /* Fall through. */
14268 {
14271 }
14272 else
14276 /* This is handled by tsubst_copy_and_build. */
14280 {
14284 }
14287 /* We shouldn't have built any of these during initial template
14288 generation. Instead, they should be built during instantiation
14289 in response to the saved STMT_IS_FULL_EXPR_P setting. */
14293 {
14303 }
14321 {
14322 /* Instantiate any typedefs in the type. */
14327 }
14330 /* These can sometimes show up in a partial instantiation, but never
14331 involve template parms. */
14345 /* We shouldn't get here, but keep going if !flag_checking. */
14349 }
14350 }
14352 /* Helper function for tsubst_omp_clauses, used for instantiation of
14353 OMP_CLAUSE_DECL of clauses. */
14355 static tree
14357 tree in_decl)
14358 {
14362 /* Handle an OpenMP array section represented as a TREE_LIST (or
14363 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
14364 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
14365 TREE_LIST. We can handle it exactly the same as an array section
14366 (purpose, value, and a chain), even though the nomenclature
14367 (low_bound, length, etc) is different. */
14369 {
14370 tree low_bound
14376 in_decl);
14385 }
14388 /* Undo convert_from_reference tsubst_expr could have called. */
14394 }
14396 /* Like tsubst_copy, but specifically for OpenMP clauses. */
14398 static tree
14401 {
14406 {
14412 {
14415 {
14421 }
14422 /* FALLTHRU */
14437 in_decl);
14468 {
14471 {
14478 }
14479 else
14481 }
14484 in_decl);
14490 in_decl);
14498 in_decl);
14500 {
14503 }
14508 else
14511 in_decl,
14534 {
14538 loc;
14540 {
14543 }
14544 }
14548 }
14551 {
14561 /* tsubst_expr on SCOPE_REF results in returning
14562 finish_non_static_data_member result. Undo that here. */
14566 {
14571 {
14575 CASE_CONVERT:
14584 /* FALLTHRU */
14588 }
14589 }
14595 {
14598 {
14602 }
14603 }
14607 }
14608 }
14612 {
14617 {
14620 }
14621 }
14623 }
14625 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
14627 static tree
14629 tree in_decl)
14630 {
14631 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
14651 {
14654 else
14655 {
14659 }
14660 }
14665 #undef RECUR
14666 }
14668 /* Used to temporarily communicate the list of #pragma omp parallel
14669 clauses to #pragma omp for instantiation if they are combined
14670 together. */
14674 /* Substitute one OMP_FOR iterator. */
14676 static void
14681 {
14682 #define RECUR(NODE) \
14683 tsubst_expr ((NODE), args, complain, in_decl, \
14684 integral_constant_expression_p)
14691 {
14694 }
14700 {
14701 /* We need to jump through some hoops to handle declarations in the
14702 for-init-statement, since we might need to handle auto deduction,
14703 but we need to keep control of initialization. */
14707 }
14708 else
14709 {
14711 {
14714 {
14718 {
14722 CASE_CONVERT:
14730 {
14733 }
14734 /* FALLTHRU */
14738 }
14739 }
14740 }
14741 else
14743 }
14754 {
14756 {
14757 /* Declare the variable, but don't let that initialize it. */
14762 }
14767 {
14772 }
14773 else
14780 }
14783 {
14784 /* Declare and initialize the variable. */
14787 }
14789 {
14793 {
14795 {
14801 {
14804 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
14809 }
14812 {
14814 decl);
14816 }
14819 {
14821 decl);
14823 }
14824 else
14826 }
14829 }
14831 {
14836 {
14839 }
14840 }
14841 }
14844 {
14848 }
14849 else
14853 {
14864 {
14872 }
14873 else
14879 {
14885 }
14889 {
14897 }
14898 else
14904 }
14910 #undef RECUR
14911 }
14913 /* Helper function of tsubst_expr, find OMP_TEAMS inside
14914 of OMP_TARGET's body. */
14916 static tree
14918 {
14921 {
14930 }
14932 }
14934 /* Like tsubst_copy for expressions, etc. but also does semantic
14935 processing. */
14937 tree
14940 {
14941 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
14942 #define RECUR(NODE) \
14943 tsubst_expr ((NODE), args, complain, in_decl, \
14944 integral_constant_expression_p)
14947 tree r;
14948 location_t loc;
14960 {
14962 {
14963 tree_stmt_iterator i;
14967 }
14982 else
14991 {
14993 tree init;
14999 {
15002 tree decl;
15010 else
15012 }
15014 {
15015 /* Don't build up decls for a variadic capture proxy, we'll
15016 instantiate the elements directly as needed. */
15018 }
15019 else
15020 {
15024 {
15025 /* By marking the declaration as instantiated, we avoid
15026 trying to instantiate it. Since instantiate_decl can't
15027 handle local variables, and since we've already done
15028 all that needs to be done, that's the right thing to
15029 do. */
15034 /* Anonymous aggregates are a special case. */
15037 {
15040 {
15044 }
15046 }
15052 {
15057 }
15058 else
15059 {
15064 {
15065 /* For __PRETTY_FUNCTION__ we have to adjust the
15066 initializer. */
15070 }
15071 else
15075 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
15078 }
15079 }
15080 }
15083 }
15098 {
15108 }
15135 {
15139 }
15147 else
15155 else
15176 {
15180 }
15184 {
15186 tree label;
15191 }
15197 /* Computed goto's must be tsubst'd into. On the other hand,
15198 non-computed gotos must not be; the identifier in question
15199 will have no binding. */
15201 else
15207 {
15223 }
15228 {
15233 }
15234 else
15235 {
15240 else
15247 else
15253 else
15255 }
15259 {
15263 {
15265 /* Prevent instantiate_decl from trying to instantiate
15266 this variable. We've already done all that needs to be
15267 done. */
15270 }
15275 }
15281 {
15282 /* Local classes are not independent templates; they are
15283 instantiated along with their containing function. And this
15284 way we don't have to deal with pushing out of one local class
15285 to instantiate a member of another local class. */
15286 tree fn;
15287 /* Closures are handled by the LAMBDA_EXPR. */
15293 }
15297 {
15298 tree condition;
15301 condition =
15303 args,
15312 }
15318 in_decl);
15355 {
15367 {
15374 }
15386 integral_constant_expression_p);
15397 else
15398 {
15406 }
15410 }
15415 /* FALLTHRU */
15450 {
15453 {
15454 /* For combined target teams, ensure the num_teams and
15455 thread_limit clause expressions are evaluated on the host,
15456 before entering the target construct. */
15457 tree c;
15463 {
15472 OMP_CLAUSE_FIRSTPRIVATE);
15476 }
15477 }
15478 }
15538 {
15543 {
15546 }
15552 }
15553 else
15554 {
15561 {
15564 }
15567 {
15572 {
15575 }
15581 }
15582 else
15583 {
15587 }
15590 }
15594 {
15600 {
15604 {
15609 }
15613 }
15614 else
15615 {
15620 }
15621 }
15625 {
15629 }
15649 /* If the first operand was a statement, we're done with it. */
15653 complain));
15665 integral_constant_expression_p));
15666 }
15669 out:
15672 #undef RECUR
15673 #undef RETURN
15674 }
15676 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
15677 function. For description of the body see comment above
15678 cp_parser_omp_declare_reduction_exprs. */
15680 static void
15682 {
15688 tree_stmt_iterator tsi;
15699 {
15718 }
15720 {
15740 }
15741 }
15743 /* T is a postfix-expression that is not being used in a function
15744 call. Return the substituted version of T. */
15746 static tree
15748 tsubst_flags_t complain,
15749 tree in_decl)
15750 {
15754 else
15760 }
15762 /* Like tsubst but deals with expressions and performs semantic
15763 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
15765 tree
15767 tree args,
15768 tsubst_flags_t complain,
15769 tree in_decl,
15772 {
15773 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
15774 #define RECUR(NODE) \
15775 tsubst_copy_and_build (NODE, args, complain, in_decl, \
15777 integral_constant_expression_p)
15780 location_t loc;
15789 /* N3276 decltype magic only applies to calls at the top level or on the
15790 right side of a comma. */
15795 {
15798 /* Fall through. */
15800 {
15801 tree decl;
15802 cp_id_kind idk;
15807 {
15810 }
15812 /* Look up the name. */
15815 /* By convention, expressions use ERROR_MARK_NODE to indicate
15816 failure, not NULL_TREE. */
15822 integral_constant_expression_p,
15830 input_location);
15834 {
15838 }
15840 }
15843 {
15844 tree object;
15854 {
15857 {
15860 }
15862 }
15865 {
15868 }
15869 else
15876 else
15878 }
15881 {
15885 {
15886 /* A type conversion to reference type will be enclosed in
15887 such an indirect ref, but the substitution of the cast
15888 will have also added such an indirect ref. */
15891 }
15892 else
15896 }
15899 {
15903 }
15906 {
15913 flags));
15914 }
15917 {
15921 }
15928 {
15929 tree type;
15935 {
15940 }
15946 {
15964 }
15967 }
16001 else
16003 in_decl);
16038 {
16045 tree r = build_x_binary_op
16047 op0,
16049 ? ERROR_MARK
16051 op1,
16053 ? ERROR_MARK
16061 }
16064 {
16068 }
16081 {
16090 }
16094 /* Fall through */
16097 {
16098 tree r;
16104 {
16105 /* When there are no ARGS, we are trying to evaluate a
16106 non-dependent expression from the parser. Trying to do
16107 the substitutions may not work. */
16110 }
16111 else
16112 {
16117 else
16120 /*integral_constant_expression_p=*/
16124 }
16128 else
16132 {
16134 {
16136 {
16140 }
16141 else
16145 }
16147 }
16149 }
16152 {
16162 }
16178 {
16182 tree r = build_x_modify_expr
16185 /* TREE_NO_WARNING must be set if either the expression was
16186 parenthesized or it uses an operator such as >>= rather
16187 than plain assignment. In the former case, it was already
16188 set and must be copied. In the latter case,
16189 build_x_modify_expr sets it and it must not be reset
16190 here. */
16195 }
16200 /* Remember that there was a reference to this entity. */
16207 {
16212 tree ret;
16216 else
16217 {
16221 }
16223 /* If there was an initializer in the original tree, but it
16224 instantiated to an empty list, then we should pass a
16225 non-NULL empty vector to tell build_new that it was an
16226 empty initializer() rather than no initializer. This can
16227 only happen when the initializer is a pack expansion whose
16228 parameter packs are of length zero. */
16231 else
16232 {
16236 else
16237 {
16240 }
16241 }
16247 complain);
16255 }
16258 {
16264 complain));
16265 }
16268 {
16272 integral_constant_expression_p);
16274 op0,
16277 }
16280 {
16281 tree function;
16286 tree ret;
16289 /* When we parsed the expression, we determined whether or
16290 not Koenig lookup should be performed. */
16293 {
16298 }
16300 {
16301 /* Do nothing; calling tsubst_copy_and_build on an identifier
16302 would incorrectly perform unqualified lookup again.
16304 Note that we can also have an IDENTIFIER_NODE if the earlier
16305 unqualified lookup found a member function; in that case
16306 koenig_p will be false and we do want to do the lookup
16307 again to find the instantiated member function.
16309 FIXME but doing that causes c++/15272, so we need to stop
16310 using IDENTIFIER_NODE in that situation. */
16312 }
16313 else
16314 {
16316 {
16322 }
16323 else
16328 /* Avoid error about taking the address of a constructor. */
16332 in_decl,
16334 integral_constant_expression_p);
16338 }
16343 {
16348 else
16349 {
16350 /* Expand the pack expansion and push each entry onto
16351 CALL_ARGS. */
16354 {
16359 {
16364 }
16365 }
16366 else
16367 {
16368 /* A partial substitution. Add one entry. */
16370 }
16371 }
16372 }
16374 /* We do not perform argument-dependent lookup if normal
16375 lookup finds a non-function, in accordance with the
16376 expected resolution of DR 218. */
16379 /* If lookup found a member function, the Koenig lookup is
16380 not appropriate, even if an unqualified-name was used
16381 to denote the function. */
16384 /* Only do this when substitution turns a dependent call
16385 into a non-dependent call. */
16392 {
16394 {
16395 /* For backwards compatibility and good diagnostics, try
16396 the unqualified lookup again if we aren't in SFINAE
16397 context. */
16398 tree unq = (tsubst_copy_and_build
16400 integral_constant_expression_p));
16405 {
16414 "%qD was not declared in this scope, "
16415 "and no declarations were found by "
16416 "argument-dependent lookup at the point "
16418 {
16422 {
16424 input_location);
16426 "declarations in dependent base %qT are "
16432 else
16436 }
16437 else
16439 "%qD declared here, later in the "
16441 }
16443 }
16444 }
16446 {
16451 }
16452 }
16454 /* Remember that there was a reference to this entity. */
16459 /* Put back tf_decltype for the actual call. */
16464 complain);
16466 {
16481 complain);
16482 else
16483 ret = (build_new_method_call
16488 complain));
16489 }
16490 else
16493 koenig_p,
16494 complain);
16499 }
16502 {
16508 {
16510 {
16515 }
16516 else
16517 {
16522 }
16524 }
16525 else
16526 {
16529 }
16533 }
16536 {
16541 input_location));
16542 }
16545 {
16553 {
16554 /* We have pack expansions, so expand those and
16555 create a new list out of it. */
16558 tree chain;
16561 /* Expand the argument expressions. */
16569 /* Build the rest of the list. */
16574 /* Determine the number of arguments. */
16576 {
16579 }
16582 else
16583 {
16584 /* Since we only performed a partial substitution into
16585 the argument pack, we only RETURN (a single list
16586 node. */
16593 }
16595 /* Convert the argument vectors into a TREE_LIST */
16598 {
16599 /* Grab the Ith values. */
16600 i--;
16603 value
16607 /* Build the list (backwards). */
16609 }
16612 }
16628 }
16631 {
16632 tree object;
16633 tree object_type;
16634 tree member;
16635 tree r;
16639 /* Remember that there was a reference to this entity. */
16650 else
16658 {
16660 {
16665 {
16668 }
16670 {
16675 }
16676 }
16677 }
16680 {
16681 /* Lookup the template functions now that we know what the
16682 scope is. */
16690 {
16693 args);
16694 member = (adjust_result_of_qualified_name_lookup
16696 object_type));
16697 }
16698 else
16699 {
16701 input_location);
16703 }
16704 }
16708 {
16710 {
16714 else
16717 }
16719 }
16721 {
16726 }
16730 complain);
16734 }
16741 {
16749 tree r;
16754 /* digest_init will do the wrong thing if we let it. */
16758 /* We do not want to process the index of aggregate
16759 initializers as they are identifier nodes which will be
16760 looked up by digest_init. */
16766 {
16768 /* An identifier index is looked up in the type
16769 being initialized, not the current scope. */
16774 {
16775 /* Substitute into the pack expansion. */
16777 in_decl);
16781 ;
16783 /* Just move the argument into place. */
16785 else
16786 {
16787 /* Update the length of the final CONSTRUCTOR
16788 arguments vector, and note that we will need to
16789 copy.*/
16792 }
16793 }
16794 else
16796 }
16799 {
16804 {
16806 {
16811 }
16812 else
16814 }
16815 }
16825 }
16828 {
16831 {
16834 }
16835 else
16836 {
16839 }
16840 }
16846 {
16847 /* We don't build decls for an instantiation of a
16848 variadic capture proxy, we instantiate the elements
16849 when needed. */
16852 }
16853 /* Fall through */
16856 {
16858 /* ??? We're doing a subset of finish_id_expression here. */
16860 && !processing_template_decl
16861 && !cp_unevaluated_operand
16864 {
16866 /* Replace an evaluated use of the thread_local variable with
16867 a call to its wrapper. */
16869 }
16871 {
16875 }
16878 /* If the original type was a reference, we'll be wrapped in
16879 the appropriate INDIRECT_REF. */
16882 }
16885 {
16889 }
16896 {
16907 }
16910 {
16916 integral_constant_expression_p);
16920 /* If the resulting list of expression statement is empty,
16921 fold it further into void_node. */
16926 }
16929 {
16947 /* For a function or variable scope, we want to use tsubst so that we
16948 don't complain about referring to an auto before deduction. */
16951 {
16952 /* Look up the parameter we want directly, as tsubst_copy
16953 doesn't do what we need. */
16959 /* FIXME Work around the parm not having DECL_CONTEXT set. */
16962 }
16964 /* For a field, use tsubst_copy so that we look up the existing field
16965 rather than build a new one. */
16967 else
16976 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
16978 /* Now that we know visibility, instantiate the type so we have a
16979 declaration of the op() for later calls to lambda_function. */
16987 }
16990 /* We can get here for a constant initializer of non-dependent type.
16991 FIXME stop folding in cp_parser_initializer_clause. */
16992 {
16994 complain);
16996 }
17000 integral_constant_expression_p));
17006 {
17011 complain));
17012 }
17018 /* Handle Objective-C++ constructs, if appropriate. */
17019 {
17020 tree subst
17025 }
17027 }
17029 #undef RECUR
17030 #undef RETURN
17031 out:
17034 }
17036 /* Verify that the instantiated ARGS are valid. For type arguments,
17037 make sure that the type's linkage is ok. For non-type arguments,
17038 make sure they are constants if they are integral or enumerations.
17039 Emit an error under control of COMPLAIN, and return TRUE on error. */
17041 static bool
17043 {
17047 {
17057 }
17059 {
17060 /* [basic.link]: A name with no linkage (notably, the name
17061 of a class or enumeration declared in a local scope)
17062 shall not be used to declare an entity with linkage.
17063 This implies that names with no linkage cannot be used as
17064 template arguments
17066 DR 757 relaxes this restriction for C++0x. */
17071 {
17072 /* DR 488 makes use of a type with no linkage cause
17073 type deduction to fail. */
17075 {
17078 else
17081 }
17083 }
17084 /* In order to avoid all sorts of complications, we do not
17085 allow variably-modified types as template arguments. */
17087 {
17091 }
17092 }
17093 /* Class template and alias template arguments should be OK. */
17095 ;
17096 /* A non-type argument of integral or enumerated type must be a
17097 constant. */
17102 {
17106 }
17108 }
17110 static bool
17112 {
17117 {
17120 }
17124 }
17126 /* We're out of SFINAE context now, so generate diagnostics for the access
17127 errors we saw earlier when instantiating D from TMPL and ARGS. */
17129 static void
17131 {
17143 }
17145 /* Instantiate the indicated variable, function, or alias template TMPL with
17146 the template arguments in TARG_PTR. */
17148 static tree
17150 {
17152 tree fndecl;
17153 tree gen_tmpl;
17154 tree spec;
17162 /* If this function is a clone, handle it specially. */
17164 {
17165 tree spec;
17166 tree clone;
17168 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
17169 DECL_CLONED_FUNCTION. */
17175 /* Look for the clone. */
17179 /* We should always have found the clone by now. */
17182 }
17187 /* Check to see if we already have this specialization. */
17190 /* The TMPL is a partial instantiation. To get a full set of
17191 arguments we must add the arguments used to perform the
17192 partial instantiation. */
17194 targ_ptr);
17196 /* It would be nice to avoid hashing here and then again in tsubst_decl,
17197 but it doesn't seem to be on the hot path. */
17206 {
17208 {
17212 }
17214 }
17217 complain))
17220 /* We are building a FUNCTION_DECL, during which the access of its
17221 parameters and return types have to be checked. However this
17222 FUNCTION_DECL which is the desired context for access checking
17223 is not built yet. We solve this chicken-and-egg problem by
17224 deferring all checks until we have the FUNCTION_DECL. */
17227 /* Instantiation of the function happens in the context of the function
17228 template, not the context of the overload resolution we're doing. */
17230 /* If there are dependent arguments, e.g. because we're doing partial
17231 ordering, make sure processing_template_decl stays set. */
17235 {
17239 }
17244 {
17245 /* We need to determine if we're using a partial or explicit
17246 specialization now, because the type of the variable could be
17247 different. */
17253 {
17257 }
17258 }
17260 /* Substitute template parameters to obtain the specialization. */
17267 {
17270 }
17272 /* The DECL_TI_TEMPLATE should always be the immediate parent
17273 template, not the most general template. */
17277 /* Now we know the specialization, compute access previously
17278 deferred. */
17285 /* If we've just instantiated the main entry point for a function,
17286 instantiate all the alternate entry points as well. We do this
17287 by cloning the instantiation of the main entry point, not by
17288 instantiating the template clones. */
17293 {
17295 {
17296 /* Remember to reinstantiate when we're out of SFINAE so the user
17297 can see the errors. */
17299 }
17301 }
17303 }
17305 /* Wrapper for instantiate_template_1. */
17307 tree
17309 {
17310 tree ret;
17315 }
17317 /* Instantiate the alias template TMPL with ARGS. Also push a template
17318 instantiation level, which instantiate_template doesn't do because
17319 functions and variables have sufficient context established by the
17320 callers. */
17322 static tree
17324 {
17331 {
17334 }
17336 args =
17344 /* We can't free this if a pending_template entry or last_error_tinst_level
17345 is pointing at it. */
17351 }
17353 /* PARM is a template parameter pack for FN. Returns true iff
17354 PARM is used in a deducible way in the argument list of FN. */
17356 static bool
17358 {
17361 {
17363 tree packs;
17369 {
17370 /* The template parameter pack is used in a function parameter
17371 pack. If this is the end of the parameter list, the
17372 template parameter pack is deducible. */
17375 else
17376 /* Otherwise, not. Well, it could be deduced from
17377 a non-pack parameter, but doing so would end up with
17378 a deduction mismatch, so don't bother. */
17380 }
17381 }
17382 /* The template parameter pack isn't used in any function parameter
17383 packs, but it might be used deeper, e.g. tuple<Args...>. */
17385 }
17387 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
17388 NARGS elements of the arguments that are being used when calling
17389 it. TARGS is a vector into which the deduced template arguments
17390 are placed.
17392 Returns either a FUNCTION_DECL for the matching specialization of FN or
17393 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
17394 true, diagnostics will be printed to explain why it failed.
17396 If FN is a conversion operator, or we are trying to produce a specific
17397 specialization, RETURN_TYPE is the return type desired.
17399 The EXPLICIT_TARGS are explicit template arguments provided via a
17400 template-id.
17402 The parameter STRICT is one of:
17404 DEDUCE_CALL:
17405 We are deducing arguments for a function call, as in
17406 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
17407 deducing arguments for a call to the result of a conversion
17408 function template, as in [over.call.object].
17410 DEDUCE_CONV:
17411 We are deducing arguments for a conversion function, as in
17412 [temp.deduct.conv].
17414 DEDUCE_EXACT:
17415 We are deducing arguments when doing an explicit instantiation
17416 as in [temp.explicit], when determining an explicit specialization
17417 as in [temp.expl.spec], or when taking the address of a function
17418 template, as in [temp.deduct.funcaddr]. */
17420 tree
17422 tree explicit_targs,
17423 tree targs,
17426 tree return_type,
17427 unification_kind_t strict,
17431 {
17432 tree parms;
17433 tree fntype;
17441 tree tinst;
17447 /* In C++0x, it's possible to have a function template whose type depends
17448 on itself recursively. This is most obvious with decltype, but can also
17449 occur with enumeration scope (c++/48969). So we need to catch infinite
17450 recursion and reject the substitution at deduction time; this function
17451 will return error_mark_node for any repeated substitution.
17453 This also catches excessive recursion such as when f<N> depends on
17454 f<N-1> across all integers, and returns error_mark_node for all the
17455 substitutions back up to the initial one.
17457 This is, of course, not reentrant. */
17467 {
17468 /* [temp.deduct]
17470 The specified template arguments must match the template
17471 parameters in kind (i.e., type, nontype, template), and there
17472 must not be more arguments than there are parameters;
17473 otherwise type deduction fails.
17475 Nontype arguments must match the types of the corresponding
17476 nontype template parameters, or must be convertible to the
17477 types of the corresponding nontype parameters as specified in
17478 _temp.arg.nontype_, otherwise type deduction fails.
17480 All references in the function type of the function template
17481 to the corresponding template parameters are replaced by the
17482 specified template argument values. If a substitution in a
17483 template parameter or in the function type of the function
17484 template results in an invalid type, type deduction fails. */
17489 /* Adjust any explicit template arguments before entering the
17490 substitution context. */
17491 explicit_targs
17493 complain,
17499 /* Substitute the explicit args into the function type. This is
17500 necessary so that, for instance, explicitly declared function
17501 arguments can match null pointed constants. If we were given
17502 an incomplete set of explicit args, we must not do semantic
17503 processing during substitution as we could create partial
17504 instantiations. */
17506 {
17511 /* Dig out the actual parm. */
17514 {
17517 }
17519 {
17522 }
17525 /* No explicit argument for this template parameter. */
17529 {
17530 /* Mark the argument pack as "incomplete". We could
17531 still deduce more arguments during unification.
17532 We remove this mark in type_unification_real. */
17534 {
17538 }
17540 /* We have some incomplete argument packs. */
17542 }
17543 }
17547 {
17550 }
17553 /* Ignore any access checks; we'll see them again in
17554 instantiate_template and they might have the wrong
17555 access path at this point. */
17567 /* Place the explicitly specified arguments in TARGS. */
17570 }
17572 /* Never do unification on the 'this' parameter. */
17576 {
17577 /* We're deducing for a call to the result of a template conversion
17578 function. The parms we really want are in return_type. */
17582 }
17584 {
17593 }
17595 /* We allow incomplete unification without an error message here
17596 because the standard doesn't seem to explicitly prohibit it. Our
17597 callers must be ready to deal with unification failures in any
17598 event. */
17601 /* If we aren't explaining yet, push tinst context so we can see where
17602 any errors (e.g. from class instantiations triggered by instantiation
17603 of default template arguments) come from. If we are explaining, this
17604 context is redundant. */
17606 {
17609 }
17611 /* type_unification_real will pass back any access checks from default
17612 template argument substitution. */
17624 /* Now that we have bindings for all of the template arguments,
17625 ensure that the arguments deduced for the template template
17626 parameters have compatible template parameter lists. We cannot
17627 check this property before we have deduced all template
17628 arguments, because the template parameter types of a template
17629 template parameter might depend on prior template parameters
17630 deduced after the template template parameter. The following
17631 ill-formed example illustrates this issue:
17633 template<typename T, template<T> class C> void f(C<5>, T);
17635 template<int N> struct X {};
17637 void g() {
17638 f(X<5>(), 5l); // error: template argument deduction fails
17639 }
17641 The template parameter list of 'C' depends on the template type
17642 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
17643 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
17644 time that we deduce 'C'. */
17647 {
17650 }
17652 /* All is well so far. Now, check:
17654 [temp.deduct]
17656 When all template arguments have been deduced, all uses of
17657 template parameters in nondeduced contexts are replaced with
17658 the corresponding deduced argument values. If the
17659 substitution results in an invalid type, as described above,
17660 type deduction fails. */
17663 {
17666 }
17668 /* Also collect access checks from the instantiation. */
17681 /* Now perform any access checks encountered during substitution. */
17688 /* If we're looking for an exact match, check that what we got
17689 is indeed an exact match. It might not be if some template
17690 parameters are used in non-deduced contexts. But don't check
17691 for an exact match if we have dependent template arguments;
17692 in that case we're doing partial ordering, and we already know
17693 that we have two candidates that will provide the actual type. */
17695 {
17699 tree sarg
17705 {
17709 }
17710 }
17714 fail:
17717 {
17719 /* Reset once we're all the way out. */
17721 }
17723 /* We can't free this if a pending_template entry or last_error_tinst_level
17724 is pointing at it. */
17730 }
17732 /* Adjust types before performing type deduction, as described in
17733 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
17734 sections are symmetric. PARM is the type of a function parameter
17735 or the return type of the conversion function. ARG is the type of
17736 the argument passed to the call, or the type of the value
17737 initialized with the result of the conversion function.
17738 ARG_EXPR is the original argument expression, which may be null. */
17740 static int
17744 tree arg_expr)
17745 {
17749 {
17754 /* Swap PARM and ARG throughout the remainder of this
17755 function; the handling is precisely symmetric since PARM
17756 will initialize ARG rather than vice versa. */
17761 /* Core issue #873: Do the DR606 thing (see below) for these cases,
17762 too, but here handle it by stripping the reference from PARM
17763 rather than by adding it to ARG. */
17771 /* Nothing else to do in this case. */
17776 }
17779 {
17780 /* [temp.deduct.call]
17782 If P is not a reference type:
17784 --If A is an array type, the pointer type produced by the
17785 array-to-pointer standard conversion (_conv.array_) is
17786 used in place of A for type deduction; otherwise,
17788 --If A is a function type, the pointer type produced by
17789 the function-to-pointer standard conversion
17790 (_conv.func_) is used in place of A for type deduction;
17791 otherwise,
17793 --If A is a cv-qualified type, the top level
17794 cv-qualifiers of A's type are ignored for type
17795 deduction. */
17800 else
17802 }
17804 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
17805 of the form T&&, where T is a template parameter, and the argument
17806 is an lvalue, T is deduced as A& */
17812 /* try_one_overload doesn't provide an arg_expr, but
17813 functions are always lvalues. */
17817 /* [temp.deduct.call]
17819 If P is a cv-qualified type, the top level cv-qualifiers
17820 of P's type are ignored for type deduction. If P is a
17821 reference type, the type referred to by P is used for
17822 type deduction. */
17825 {
17828 }
17830 /* DR 322. For conversion deduction, remove a reference type on parm
17831 too (which has been swapped into ARG). */
17836 }
17838 /* Subroutine of unify_one_argument. PARM is a function parameter of a
17839 template which does contain any deducible template parameters; check if
17840 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
17841 unify_one_argument. */
17843 static int
17846 {
17847 tree type;
17851 else
17858 {
17862 }
17864 {
17869 }
17873 else
17875 }
17879 /* Returns true iff the expression EXPR is one from which a template
17880 argument can be deduced. In other words, if it's an undecorated
17881 use of a template non-type parameter. */
17883 static bool
17885 {
17887 }
17889 /* Returns true iff the array domain DOMAIN uses a template parameter in a
17890 deducible way; that is, if it has a max value of <PARM> - 1. */
17892 static bool
17894 {
17903 }
17905 /* Returns true iff the template arguments ARGS use a template parameter
17906 in a deducible way. */
17908 static bool
17910 {
17912 {
17917 else
17918 {
17925 else
17927 }
17930 }
17932 }
17934 /* Returns true iff TYPE contains any deducible references to template
17935 parameters, as per 14.8.2.5. */
17937 static bool
17939 {
17943 /* T
17944 cv-list T
17945 TT<T>
17946 TT<i>
17947 TT<> */
17952 /* T*
17953 T&
17954 T&& */
17958 /* T[integer-constant ]
17959 type [i] */
17964 /* T type ::*
17965 type T::*
17966 T T::*
17967 T (type ::*)()
17968 type (T::*)()
17969 type (type ::*)(T)
17970 type (T::*)(T)
17971 T (type ::*)(T)
17972 T (T::*)()
17973 T (T::*)(T) */
17976 || (uses_deducible_template_parms
17979 /* template-name <T> (where template-name refers to a class template)
17980 template-name <i> (where template-name refers to a class template) */
17987 /* type (T)
17988 T()
17989 T(T) */
17992 {
18001 }
18004 }
18006 /* Subroutine of type_unification_real and unify_pack_expansion to
18007 handle unification of a single P/A pair. Parameters are as
18008 for those functions. */
18010 static int
18014 {
18021 /* We can't deduce anything from this, but we might get all the
18022 template args from other function args. */
18025 /* Implicit conversions (Clause 4) will be performed on a function
18026 argument to convert it to the type of the corresponding function
18027 parameter if the parameter type contains no template-parameters that
18028 participate in template argument deduction. */
18031 /* For function parameters with no deducible template parameters,
18032 just return. We'll check non-dependent conversions later. */
18036 {
18038 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
18039 | UNIFY_ALLOW_MORE_CV_QUAL
18053 }
18055 /* We only do these transformations if this is the top-level
18056 parameter_type_list in a call or declaration matching; in other
18057 situations (nested function declarators, template argument lists) we
18058 won't be comparing a type to an expression, and we don't do any type
18059 adjustments. */
18061 {
18063 {
18066 {
18067 /* [temp.deduct.type] A template-argument can be
18068 deduced from a pointer to function or pointer
18069 to member function argument if the set of
18070 overloaded functions does not contain function
18071 templates and at most one of a set of
18072 overloaded functions provides a unique
18073 match. */
18080 }
18086 }
18088 arg_strict |=
18090 }
18091 else
18096 /* For deduction from an init-list we need the actual list. */
18100 }
18102 /* Most parms like fn_type_unification.
18104 If SUBR is 1, we're being called recursively (to unify the
18105 arguments of a function or method parameter of a function
18106 template).
18108 CHECKS is a pointer to a vector of access checks encountered while
18109 substituting default template arguments. */
18111 static int
18113 tree targs,
18114 tree xparms,
18118 unification_kind_t strict,
18122 {
18127 tree parms;
18136 /* Reset the number of non-defaulted template arguments contained
18137 in TARGS. */
18140 again:
18148 {
18153 /* For a function parameter pack that occurs at the end of the
18154 parameter-declaration-list, the type A of each remaining
18155 argument of the call is compared with the type P of the
18156 declarator-id of the function parameter pack. */
18162 /* For a function parameter pack that does not occur at the
18163 end of the parameter-declaration-list, the type of the
18164 parameter pack is a non-deduced context. */
18171 explain_p))
18173 }
18178 {
18179 /* Unify the remaining arguments with the pack expansion type. */
18180 tree argvec;
18183 /* Allocate a TREE_VEC and copy in all of the arguments */
18188 /* Copy the parameter into parmvec. */
18194 /* Advance to the end of the list of parameters. */
18196 }
18198 /* Fail if we've reached the end of the parm list, and more args
18199 are present, and the parm list isn't variadic. */
18202 /* Fail if parms are left and they don't have default values and
18203 they aren't all deduced as empty packs (c++/57397). This is
18204 consistent with sufficient_parms_p. */
18207 {
18211 do
18212 {
18215 count++;
18217 }
18221 type_pack_p);
18222 }
18225 {
18226 tsubst_flags_t complain = (explain_p
18227 ? tf_warning_or_error
18231 {
18235 /* Clear the "incomplete" flags on all argument packs now so that
18236 substituting them into later default arguments works. */
18238 {
18241 }
18247 /* If this is an undeduced nontype parameter that depends on
18248 a type parameter, try another pass; its type may have been
18249 deduced from a later argument than the one from which
18250 this parameter can be deduced. */
18254 {
18257 }
18259 /* Core issue #226 (C++0x) [temp.deduct]:
18261 If a template argument has not been deduced, its
18262 default template argument, if any, is used.
18264 When we are in C++98 mode, TREE_PURPOSE will either
18265 be NULL_TREE or ERROR_MARK_NODE, so we do not need
18266 to explicitly check cxx_dialect here. */
18268 /* OK, there is a default argument. Wait until after the
18269 conversion check to do substitution. */
18272 /* If the type parameter is a parameter pack, then it will
18273 be deduced to an empty parameter pack. */
18275 {
18276 tree arg;
18279 {
18283 }
18284 else
18291 }
18294 }
18296 /* DR 1391: All parameters have args, now check non-dependent parms for
18297 convertibility. */
18301 {
18307 /* For a function parameter pack that occurs at the end of the
18308 parameter-declaration-list, the type A of each remaining
18309 argument of the call is compared with the type P of the
18310 declarator-id of the function parameter pack. */
18316 /* For a function parameter pack that does not occur at the
18317 end of the parameter-declaration-list, the type of the
18318 parameter pack is a non-deduced context. */
18327 explain_p))
18329 }
18331 /* Now substitute into the default template arguments. */
18333 {
18359 else
18360 {
18362 /* The position of the first default template argument,
18363 is also the number of non-defaulted arguments in TARGS.
18364 Record that. */
18368 }
18369 }
18373 }
18379 }
18381 /* Subroutine of type_unification_real. Args are like the variables
18382 at the call site. ARG is an overloaded function (or template-id);
18383 we try deducing template args from each of the overloads, and if
18384 only one succeeds, we go with that. Modifies TARGS and returns
18385 true on success. */
18387 static bool
18389 tree targs,
18390 tree parm,
18391 tree arg,
18392 unification_kind_t strict,
18395 {
18402 {
18405 }
18406 else
18410 /* Handle `&x' where `x' is some static or non-static member
18411 function name. */
18417 /* Strip baselink information. */
18422 {
18423 /* If we got some explicit template args, we need to plug them into
18424 the affected templates before we try to unify, in case the
18425 explicit args will completely resolve the templates in question. */
18432 {
18445 {
18450 {
18453 }
18454 }
18457 }
18458 /* If no templates (or more than one) are fully resolved by the
18459 explicit arguments, this template-id is a non-deduced context; it
18460 could still be OK if we deduce all template arguments for the
18461 enclosing call through other arguments. */
18464 }
18467 /* If ARG is, for example, "(0, &f)" then its type will be unknown
18468 -- but the deduction does not succeed because the expression is
18469 not just the function on its own. */
18471 else
18477 {
18480 }
18482 /* [temp.deduct.type] A template-argument can be deduced from a pointer
18483 to function or pointer to member function argument if the set of
18484 overloaded functions does not contain function templates and at most
18485 one of a set of overloaded functions provides a unique match.
18487 So if we found multiple possibilities, we return success but don't
18488 deduce anything. */
18491 {
18495 {
18500 /* Don't forget explicit template arguments in a pack. */
18504 }
18505 }
18510 }
18512 /* Core DR 115: In contexts where deduction is done and fails, or in
18513 contexts where deduction is not done, if a template argument list is
18514 specified and it, along with any default template arguments, identifies
18515 a single function template specialization, then the template-id is an
18516 lvalue for the function template specialization. */
18518 tree
18520 {
18533 {
18536 }
18538 {
18541 }
18543 {
18546 }
18549 {
18553 /* If we got some explicit template args, we need to plug them into
18554 the affected templates before we try to unify, in case the
18555 explicit args will completely resolve the templates in question. */
18563 {
18576 {
18579 {
18582 }
18584 {
18587 }
18588 }
18589 }
18591 {
18599 {
18600 tree base
18603 }
18607 }
18609 /* There were no good options and at least one bad one, so let the
18610 user know what the problem is. */
18612 }
18614 }
18616 /* Subroutine of resolve_overloaded_unification; does deduction for a single
18617 overload. Fills TARGS with any deduced arguments, or error_mark_node if
18618 different overloads deduce different arguments for a given parm.
18619 ADDR_P is true if the expression for which deduction is being
18620 performed was of the form "& fn" rather than simply "fn".
18622 Returns 1 on success. */
18624 static int
18626 tree orig_targs,
18627 tree targs,
18628 tree parm,
18629 tree arg,
18630 unification_kind_t strict,
18634 {
18636 tree tempargs;
18642 /* [temp.deduct.type] A template-argument can be deduced from a pointer
18643 to function or pointer to member function argument if the set of
18644 overloaded functions does not contain function templates and at most
18645 one of a set of overloaded functions provides a unique match.
18647 So if this is a template, just return success. */
18659 /* We don't copy orig_targs for this because if we have already deduced
18660 some template args from previous args, unify would complain when we
18661 try to deduce a template parameter for the same argument, even though
18662 there isn't really a conflict. */
18669 /* First make sure we didn't deduce anything that conflicts with
18670 explicitly specified args. */
18672 {
18679 /* Since we're unifying against ourselves, we will fill in
18680 template args used in the function parm list with our own
18681 template parms. Discard them. */
18685 }
18688 {
18693 }
18696 }
18698 /* PARM is a template class (perhaps with unbound template
18699 parameters). ARG is a fully instantiated type. If ARG can be
18700 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
18701 TARGS are as for unify. */
18703 static tree
18706 {
18707 tree copy_of_targs;
18714 /* We need to make a new template argument vector for the call to
18715 unify. If we used TARGS, we'd clutter it up with the result of
18716 the attempted unification, even if this class didn't work out.
18717 We also don't want to commit ourselves to all the unifications
18718 we've already done, since unification is supposed to be done on
18719 an argument-by-argument basis. In other words, consider the
18720 following pathological case:
18722 template <int I, int J, int K>
18723 struct S {};
18725 template <int I, int J>
18726 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
18728 template <int I, int J, int K>
18729 void f(S<I, J, K>, S<I, I, I>);
18731 void g() {
18732 S<0, 0, 0> s0;
18733 S<0, 1, 2> s2;
18735 f(s0, s2);
18736 }
18738 Now, by the time we consider the unification involving `s2', we
18739 already know that we must have `f<0, 0, 0>'. But, even though
18740 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
18741 because there are two ways to unify base classes of S<0, 1, 2>
18742 with S<I, I, I>. If we kept the already deduced knowledge, we
18743 would reject the possibility I=1. */
18746 /* If unification failed, we're done. */
18752 }
18754 /* Given a template type PARM and a class type ARG, find the unique
18755 base type in ARG that is an instance of PARM. We do not examine
18756 ARG itself; only its base-classes. If there is not exactly one
18757 appropriate base class, return NULL_TREE. PARM may be the type of
18758 a partial specialization, as well as a plain template type. Used
18759 by unify. */
18761 static enum template_base_result
18764 {
18766 tree binfo;
18772 {
18773 /* The type could not be completed. */
18776 }
18778 /* Walk in inheritance graph order. The search order is not
18779 important, and this avoids multiple walks of virtual bases. */
18781 {
18786 {
18787 /* If there is more than one satisfactory baseclass, then:
18789 [temp.deduct.call]
18791 If they yield more than one possible deduced A, the type
18792 deduction fails.
18794 applies. */
18796 {
18799 }
18802 }
18803 }
18807 }
18809 /* Returns the level of DECL, which declares a template parameter. */
18811 static int
18813 {
18815 {
18825 }
18827 }
18829 /* Decide whether ARG can be unified with PARM, considering only the
18830 cv-qualifiers of each type, given STRICT as documented for unify.
18831 Returns nonzero iff the unification is OK on that basis. */
18833 static int
18835 {
18841 {
18842 /* Although a CVR qualifier is ignored when being applied to a
18843 substituted template parameter ([8.3.2]/1 for example), that
18844 does not allow us to unify "const T" with "int&" because both
18845 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
18846 It is ok when we're allowing additional CV qualifiers
18847 at the outer level [14.8.2.1]/3,1st bullet. */
18857 }
18868 }
18870 /* Determines the LEVEL and INDEX for the template parameter PARM. */
18871 void
18873 {
18877 {
18880 }
18881 else
18882 {
18885 }
18886 }
18888 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
18889 do { \
18890 if (unify (TP, TA, P, A, S, EP)) \
18891 return 1; \
18892 } while (0);
18894 /* Unifies the remaining arguments in PACKED_ARGS with the pack
18895 expansion at the end of PACKED_PARMS. Returns 0 if the type
18896 deduction succeeds, 1 otherwise. STRICT is the same as in
18897 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
18898 call argument list. We'll need to adjust the arguments to make them
18899 types. SUBR tells us if this is from a recursive call to
18900 type_unification_real, or for comparing two template argument
18901 lists. */
18903 static int
18907 {
18908 tree parm
18918 /* Determine the parameter packs we will be deducing from the
18919 pattern, and record their current deductions. */
18922 {
18926 /* Determine the index and level of this parameter pack. */
18929 /* Keep track of the parameter packs and their corresponding
18930 argument packs. */
18933 }
18935 /* Loop through all of the arguments that have not yet been
18936 unified and unify each with the pattern. */
18938 {
18939 tree parm;
18943 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
18944 or the element of its argument pack at the current index if
18945 this argument was explicitly specified. */
18947 {
18956 {
18959 }
18961 }
18963 /* If we had explicit template arguments, substitute them into the
18964 pattern before deduction. */
18966 {
18967 /* Some arguments might still be unspecified or dependent. */
18975 NULL_TREE);
18980 }
18981 else
18984 /* Unify the pattern with the current argument. */
18986 explain_p))
18989 /* For each parameter pack, collect the deduced value. */
18991 {
18997 }
18998 }
19000 /* Verify that the results of unification with the parameter packs
19001 produce results consistent with what we've seen before, and make
19002 the deduced argument packs available. */
19004 {
19011 /* By default keep the original deduced argument pack.
19012 If necessary, more specific code is going to update the
19013 resulting deduced argument later down in this function. */
19017 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
19018 actually deduce anything. */
19026 {
19027 /* If we had fewer function args than explicit template args,
19028 just use the explicits. */
19033 }
19036 {
19037 tree result;
19038 /* Build the deduced *_ARGUMENT_PACK. */
19040 {
19045 }
19046 else
19051 /* Note the deduced argument packs for this parameter
19052 pack. */
19054 }
19058 {
19059 /* We only had the explicitly-provided arguments before, but
19060 now we have a complete set of arguments. */
19066 }
19067 else
19068 {
19074 /* Inconsistent unification of this parameter pack. */
19076 bad_old_arg,
19077 bad_new_arg);
19078 }
19079 }
19082 }
19084 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
19085 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
19086 parameters and return value are as for unify. */
19088 static int
19092 {
19093 tree parm_max;
19094 tree arg_max;
19098 /* Our representation of array types uses "N - 1" as the
19099 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
19100 not an integer constant. We cannot unify arbitrarily
19101 complex expressions, so we eliminate the MINUS_EXPRs
19102 here. */
19106 {
19109 }
19113 {
19114 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
19115 trying to unify the type of a variable with the type
19116 of a template parameter. For example:
19118 template <unsigned int N>
19119 void f (char (&) [N]);
19120 int g();
19121 void h(int i) {
19122 char a[g(i)];
19123 f(a);
19124 }
19126 Here, the type of the ARG will be "int [g(i)]", and
19127 may be a SAVE_EXPR, etc. */
19131 }
19133 /* If only one of the bounds used a MINUS_EXPR, compensate
19134 by adding one to the other bound. */
19137 integer_type_node,
19138 parm_max,
19139 integer_one_node);
19142 integer_type_node,
19143 arg_max,
19144 integer_one_node);
19148 }
19150 /* Deduce the value of template parameters. TPARMS is the (innermost)
19151 set of template parameters to a template. TARGS is the bindings
19152 for those template parameters, as determined thus far; TARGS may
19153 include template arguments for outer levels of template parameters
19154 as well. PARM is a parameter to a template function, or a
19155 subcomponent of that parameter; ARG is the corresponding argument.
19156 This function attempts to match PARM with ARG in a manner
19157 consistent with the existing assignments in TARGS. If more values
19158 are deduced, then TARGS is updated.
19160 Returns 0 if the type deduction succeeds, 1 otherwise. The
19161 parameter STRICT is a bitwise or of the following flags:
19163 UNIFY_ALLOW_NONE:
19164 Require an exact match between PARM and ARG.
19165 UNIFY_ALLOW_MORE_CV_QUAL:
19166 Allow the deduced ARG to be more cv-qualified (by qualification
19167 conversion) than ARG.
19168 UNIFY_ALLOW_LESS_CV_QUAL:
19169 Allow the deduced ARG to be less cv-qualified than ARG.
19170 UNIFY_ALLOW_DERIVED:
19171 Allow the deduced ARG to be a template base class of ARG,
19172 or a pointer to a template base class of the type pointed to by
19173 ARG.
19174 UNIFY_ALLOW_INTEGER:
19175 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
19176 case for more information.
19177 UNIFY_ALLOW_OUTER_LEVEL:
19178 This is the outermost level of a deduction. Used to determine validity
19179 of qualification conversions. A valid qualification conversion must
19180 have const qualified pointers leading up to the inner type which
19181 requires additional CV quals, except at the outer level, where const
19182 is not required [conv.qual]. It would be normal to set this flag in
19183 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
19184 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
19185 This is the outermost level of a deduction, and PARM can be more CV
19186 qualified at this point.
19187 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
19188 This is the outermost level of a deduction, and PARM can be less CV
19189 qualified at this point. */
19191 static int
19194 {
19196 tree targ;
19197 tree tparm;
19200 /* I don't think this will do the right thing with respect to types.
19201 But the only case I've seen it in so far has been array bounds, where
19202 signedness is the only information lost, and I think that will be
19203 okay. */
19211 /* We can't deduce anything from this, but we might get all the
19212 template args from other function args. */
19215 /* If PARM uses template parameters, then we can't bail out here,
19216 even if ARG == PARM, since we won't record unifications for the
19217 template parameters. We might need them if we're trying to
19218 figure out which of two things is more specialized. */
19222 /* Handle init lists early, so the rest of the function can assume
19223 we're dealing with a type. */
19225 {
19230 /* Replace T with std::initializer_list<T> for deduction. */
19237 /* We can only deduce from an initializer list argument if the
19238 parameter is std::initializer_list or an array; otherwise this
19239 is a non-deduced context. */
19244 else
19245 {
19247 /* Deduction is defined in terms of a single type, so just punt
19248 on the (bizarre) std::initializer_list<T...>. */
19251 }
19254 {
19261 {
19265 /* It should only be possible to get here for a call. */
19267 elt_strict |= maybe_adjust_types_for_deduction
19270 }
19273 explain_p);
19274 }
19278 {
19279 /* Also deduce from the length of the initializer list. */
19286 }
19288 /* If the std::initializer_list<T> deduction worked, replace the
19289 deduced A with std::initializer_list<A>. */
19291 {
19296 }
19298 }
19300 /* Immediately reject some pairs that won't unify because of
19301 cv-qualification mismatches. */
19304 /* It is the elements of the array which hold the cv quals of an array
19305 type, and the elements might be template type parms. We'll check
19306 when we recurse. */
19308 /* We check the cv-qualifiers when unifying with template type
19309 parameters below. We want to allow ARG `const T' to unify with
19310 PARM `T' for example, when computing which of two templates
19311 is more specialized, for example. */
19325 {
19329 /* In a type which contains a nested-name-specifier, template
19330 argument values cannot be deduced for template parameters used
19331 within the nested-name-specifier. */
19343 /* The PARM is not one we're trying to unify. Just check
19344 to see if it matches ARG. */
19345 {
19350 else
19352 }
19359 /* Check for mixed types and values. */
19367 {
19368 /* ARG must be constructed from a template class or a template
19369 template parameter. */
19373 {
19375 /* An alias template name is never deduced. */
19380 tree parm_parms
19381 = DECL_INNERMOST_TEMPLATE_PARMS
19386 /* The resolution to DR150 makes clear that default
19387 arguments for an N-argument may not be used to bind T
19388 to a template template parameter with fewer than N
19389 parameters. It is not safe to permit the binding of
19390 default arguments as an extension, as that may change
19391 the meaning of a conforming program. Consider:
19393 struct Dense { static const unsigned int dim = 1; };
19395 template <template <typename> class View,
19396 typename Block>
19397 void operator+(float, View<Block> const&);
19399 template <typename Block,
19400 unsigned int Dim = Block::dim>
19401 struct Lvalue_proxy { operator float() const; };
19403 void
19404 test_1d (void) {
19405 Lvalue_proxy<Dense> p;
19406 float b;
19407 b + p;
19408 }
19410 Here, if Lvalue_proxy is permitted to bind to View, then
19411 the global operator+ will be used; if they are not, the
19412 Lvalue_proxy will be converted to float. */
19414 full_argvec,
19416 (explain_p
19417 ? tf_warning_or_error
19424 /* Deduce arguments T, i from TT<T> or TT<i>.
19425 We check each element of PARMVEC and ARGVEC individually
19426 rather than the whole TREE_VEC since they can have
19427 different number of elements. */
19434 /* Check if the parameters end in a pack, making them
19435 variadic. */
19441 /* If the template argument list of P contains a pack
19442 expansion that is not the last template argument, the
19443 entire template argument list is a non-deduced
19444 context. */
19453 {
19458 }
19463 DEDUCE_EXACT,
19466 }
19469 /* Fall through to deduce template name. */
19470 }
19474 {
19475 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
19477 /* Simple cases: Value already set, does match or doesn't. */
19482 }
19483 else
19484 {
19485 /* If PARM is `const T' and ARG is only `int', we don't have
19486 a match unless we are allowing additional qualification.
19487 If ARG is `const int' and PARM is just `T' that's OK;
19488 that binds `const int' to `T'. */
19493 /* Consider the case where ARG is `const volatile int' and
19494 PARM is `const T'. Then, T should be `volatile int'. */
19495 arg = cp_build_qualified_type_real
19500 /* Simple cases: Value already set, does match or doesn't. */
19506 /* Make sure that ARG is not a variable-sized array. (Note
19507 that were talking about variable-sized arrays (like
19508 `int[n]'), rather than arrays of unknown size (like
19509 `int[]').) We'll get very confused by such a type since
19510 the bound of the array is not constant, and therefore
19511 not mangleable. Besides, such types are not allowed in
19512 ISO C++, so we can do as we please here. We do allow
19513 them for 'auto' deduction, since that isn't ABI-exposed. */
19517 /* Strip typedefs as in convert_template_argument. */
19519 }
19521 /* If ARG is a parameter pack or an expansion, we cannot unify
19522 against it unless PARM is also a parameter pack. */
19527 /* If the argument deduction results is a METHOD_TYPE,
19528 then there is a problem.
19529 METHOD_TYPE doesn't map to any real C++ type the result of
19530 the deduction can not be of that type. */
19544 {
19545 /* The PARM is not one we're trying to unify. Just check
19546 to see if it matches ARG. */
19552 }
19558 {
19563 }
19565 /* [temp.deduct.type] If, in the declaration of a function template
19566 with a non-type template-parameter, the non-type
19567 template-parameter is used in an expression in the function
19568 parameter-list and, if the corresponding template-argument is
19569 deduced, the template-argument type shall match the type of the
19570 template-parameter exactly, except that a template-argument
19571 deduced from an array bound may be of any integral type.
19572 The non-type parameter might use already deduced type parameters. */
19575 /* Template-parameter dependent expression. Just accept it for now.
19576 It will later be processed in convert_template_argument. */
19577 ;
19582 /* Convert the ARG to the type of PARM; the deduced non-type
19583 template argument must exactly match the types of the
19584 corresponding parameter. */
19587 /* We haven't deduced the type of this parameter yet. Try again
19588 later. */
19590 else
19593 /* If ARG is a parameter pack or an expansion, we cannot unify
19594 against it unless PARM is also a parameter pack. */
19599 {
19602 }
19607 {
19608 /* A pointer-to-member constant can be unified only with
19609 another constant. */
19613 /* Just unify the class member. It would be useless (and possibly
19614 wrong, depending on the strict flags) to unify also
19615 PTRMEM_CST_CLASS, because we want to be sure that both parm and
19616 arg refer to the same variable, even if through different
19617 classes. For instance:
19619 struct A { int x; };
19620 struct B : A { };
19622 Unification of &A::x and &B::x must succeed. */
19625 }
19628 {
19632 /* [temp.deduct.call]
19634 A can be another pointer or pointer to member type that can
19635 be converted to the deduced A via a qualification
19636 conversion (_conv.qual_).
19638 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
19639 This will allow for additional cv-qualification of the
19640 pointed-to types if appropriate. */
19643 /* The derived-to-base conversion only persists through one
19644 level of pointers. */
19649 }
19681 /* We have already checked cv-qualification at the top of the
19682 function. */
19686 /* As far as unification is concerned, this wins. Later checks
19687 will invalidate it if necessary. */
19690 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
19691 /* Type INTEGER_CST can come from ordinary constant template args. */
19703 {
19713 /* Check for pack expansions in the parameters. */
19715 {
19717 {
19719 /* We can unify against something with a trailing
19720 parameter pack. */
19722 else
19723 /* [temp.deduct.type]/9: If the template argument list of
19724 P contains a pack expansion that is not the last
19725 template argument, the entire template argument list
19726 is a non-deduced context. */
19728 }
19729 }
19731 /* If we don't have enough arguments to satisfy the parameters
19732 (not counting the pack expression at the end), or we have
19733 too many arguments for a parameter list that doesn't end in
19734 a pack expression, we can't unify. */
19740 /* Unify all of the parameters that precede the (optional)
19741 pack expression. */
19743 {
19748 }
19751 DEDUCE_EXACT,
19754 }
19762 {
19770 }
19775 {
19779 {
19780 /* First, we try to unify the PARM and ARG directly. */
19785 {
19786 /* Fallback to the special case allowed in
19787 [temp.deduct.call]:
19789 If P is a class, and P has the form
19790 template-id, then A can be a derived class of
19791 the deduced A. Likewise, if P is a pointer to
19792 a class of the form template-id, A can be a
19793 pointer to a derived class pointed to by the
19794 deduced A. */
19800 {
19801 /* Don't give the derived diagnostic if we're
19802 already dealing with the same template. */
19803 bool same_template
19809 }
19810 }
19811 }
19815 /* Perhaps PARM is something like S<U> and ARG is S<int>.
19816 Then, we should unify `int' and `U'. */
19818 else
19819 /* There's no chance of unification succeeding. */
19824 }
19831 {
19834 tree a;
19840 /* CV qualifications for methods can never be deduced, they must
19841 match exactly. We need to check them explicitly here,
19842 because type_unification_real treats them as any other
19843 cv-qualified parameter. */
19845 && (!check_cv_quals_for_unify
19865 }
19868 /* Unify a pointer to member with a pointer to member function, which
19869 deduces the type of the member as a function type. */
19871 {
19872 /* Check top-level cv qualifiers */
19880 /* Determine the type of the function we are unifying against. */
19884 }
19903 /* Matched cases are handled by the ARG == PARM test above. */
19907 /* A non-type template parameter that is a variable should be a
19908 an integral constant, in which case, it whould have been
19909 folded into its (constant) value. So we should not be getting
19910 a variable here. */
19921 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
19922 or UNDERLYING_TYPE nodes. */
19926 /* Unification fails if we hit an error node. */
19931 {
19936 }
19937 /* FALLTHRU */
19940 /* An unresolved overload is a nondeduced context. */
19945 /* We must be looking at an expression. This can happen with
19946 something like:
19948 template <int I>
19949 void foo(S<I>, S<I + 2>);
19951 This is a "nondeduced context":
19953 [deduct.type]
19955 The nondeduced contexts are:
19957 --A type that is a template-id in which one or more of
19958 the template-arguments is an expression that references
19959 a template-parameter.
19961 In these cases, we assume deduction succeeded, but don't
19962 actually infer any unifications. */
19967 else
19969 }
19970 }
19971 #undef RECUR_AND_CHECK_FAILURE
19972 \f
19973 /* Note that DECL can be defined in this translation unit, if
19974 required. */
19976 static void
19978 {
19979 tree clone;
19983 }
19985 /* Called if RESULT is explicitly instantiated, or is a member of an
19986 explicitly instantiated class. */
19988 void
19990 {
19993 /* If this entity has already been written out, it's too late to
19994 make any modifications. */
19998 /* For anonymous namespace we don't need to do anything. */
20000 {
20003 }
20006 /* The TREE_PUBLIC flag for function declarations will have been
20007 set correctly by tsubst. */
20010 /* This might have been set by an earlier implicit instantiation. */
20015 else
20016 {
20019 /* Always make artificials weak. */
20022 /* For WIN32 we also want to put explicit instantiations in
20023 linkonce sections. */
20026 }
20028 /* If EXTERN_P, then this function will not be emitted -- unless
20029 followed by an explicit instantiation, at which point its linkage
20030 will be adjusted. If !EXTERN_P, then this function will be
20031 emitted here. In neither circumstance do we want
20032 import_export_decl to adjust the linkage. */
20034 }
20036 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
20037 important template arguments. If any are missing, we check whether
20038 they're important by using error_mark_node for substituting into any
20039 args that were used for partial ordering (the ones between ARGS and END)
20040 and seeing if it bubbles up. */
20042 static bool
20044 {
20049 {
20052 }
20054 {
20058 }
20060 }
20062 /* Given two function templates PAT1 and PAT2, return:
20064 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
20065 -1 if PAT2 is more specialized than PAT1.
20066 0 if neither is more specialized.
20068 LEN indicates the number of parameters we should consider
20069 (defaulted parameters should not be considered).
20071 The 1998 std underspecified function template partial ordering, and
20072 DR214 addresses the issue. We take pairs of arguments, one from
20073 each of the templates, and deduce them against each other. One of
20074 the templates will be more specialized if all the *other*
20075 template's arguments deduce against its arguments and at least one
20076 of its arguments *does* *not* deduce against the other template's
20077 corresponding argument. Deduction is done as for class templates.
20078 The arguments used in deduction have reference and top level cv
20079 qualifiers removed. Iff both arguments were originally reference
20080 types *and* deduction succeeds in both directions, an lvalue reference
20081 wins against an rvalue reference and otherwise the template
20082 with the more cv-qualified argument wins for that pairing (if
20083 neither is more cv-qualified, they both are equal). Unlike regular
20084 deduction, after all the arguments have been deduced in this way,
20085 we do *not* verify the deduced template argument values can be
20086 substituted into non-deduced contexts.
20088 The logic can be a bit confusing here, because we look at deduce1 and
20089 targs1 to see if pat2 is at least as specialized, and vice versa; if we
20090 can find template arguments for pat1 to make arg1 look like arg2, that
20091 means that arg2 is at least as specialized as arg1. */
20093 int
20095 {
20108 /* Remove the this parameter from non-static member functions. If
20109 one is a non-static member function and the other is not a static
20110 member function, remove the first parameter from that function
20111 also. This situation occurs for operator functions where we
20112 locate both a member function (with this pointer) and non-member
20113 operator (with explicit first operand). */
20115 {
20120 }
20122 {
20125 {
20126 len--;
20128 }
20129 }
20131 /* If only one is a conversion operator, they are unordered. */
20135 /* Consider the return type for a conversion function */
20137 {
20140 len++;
20141 }
20143 processing_template_decl++;
20149 /* Stop when an ellipsis is seen. */
20151 {
20162 {
20163 /* When both arguments are pack expansions, we need only
20164 unify the patterns themselves. */
20168 /* This is the last comparison we need to do. */
20170 }
20173 {
20177 }
20180 {
20184 }
20190 {
20196 /* Setup the parameter vector, which contains only ARG1. */
20199 /* Setup the argument vector, which contains the remaining
20200 arguments. */
20209 /* We cannot deduce in the other direction, because ARG1 is
20210 a pack expansion but ARG2 is not. */
20212 }
20214 {
20220 /* Setup the parameter vector, which contains only ARG1. */
20223 /* Setup the argument vector, which contains the remaining
20224 arguments. */
20233 /* We cannot deduce in the other direction, because ARG2 is
20234 a pack expansion but ARG1 is not.*/
20236 }
20238 else
20239 {
20240 /* The normal case, where neither argument is a pack
20241 expansion. */
20248 }
20250 /* If we couldn't deduce arguments for tparms1 to make arg1 match
20251 arg2, then arg2 is not as specialized as arg1. */
20257 /* "If, for a given type, deduction succeeds in both directions
20258 (i.e., the types are identical after the transformations above)
20259 and both P and A were reference types (before being replaced with
20260 the type referred to above):
20261 - if the type from the argument template was an lvalue reference and
20262 the type from the parameter template was not, the argument type is
20263 considered to be more specialized than the other; otherwise,
20264 - if the type from the argument template is more cv-qualified
20265 than the type from the parameter template (as described above),
20266 the argument type is considered to be more specialized than the other;
20267 otherwise,
20268 - neither type is more specialized than the other." */
20271 {
20273 {
20276 else
20278 }
20280 {
20285 }
20286 }
20289 /* We've failed to deduce something in either direction.
20290 These must be unordered. */
20295 /* We have already processed all of the arguments in our
20296 handing of the pack expansion type. */
20301 }
20303 /* "In most cases, all template parameters must have values in order for
20304 deduction to succeed, but for partial ordering purposes a template
20305 parameter may remain without a value provided it is not used in the
20306 types being used for partial ordering."
20308 Thus, if we are missing any of the targs1 we need to substitute into
20309 origs1, then pat2 is not as specialized as pat1. This can happen when
20310 there is a nondeduced context. */
20316 processing_template_decl--;
20318 /* If both deductions succeed, the partial ordering selects the more
20319 constrained template. */
20321 {
20326 }
20328 /* All things being equal, if the next argument is a pack expansion
20329 for one function but not for the other, prefer the
20330 non-variadic function. FIXME this is bogus; see c++/41958. */
20334 {
20337 }
20343 else
20345 }
20347 /* Determine which of two partial specializations of TMPL is more
20348 specialized.
20350 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
20351 to the first partial specialization. The TREE_PURPOSE is the
20352 innermost set of template parameters for the partial
20353 specialization. PAT2 is similar, but for the second template.
20355 Return 1 if the first partial specialization is more specialized;
20356 -1 if the second is more specialized; 0 if neither is more
20357 specialized.
20359 See [temp.class.order] for information about determining which of
20360 two templates is more specialized. */
20362 static int
20364 {
20365 tree targs;
20376 /* Just like what happens for functions, if we are ordering between
20377 different template specializations, we may encounter dependent
20378 types in the arguments, and we need our dependency check functions
20379 to behave correctly. */
20383 {
20386 }
20390 {
20393 }
20396 /* If both deductions succeed, the partial ordering selects the more
20397 constrained template. */
20401 /* In the case of a tie where at least one of the templates
20402 has a parameter pack at the end, the template with the most
20403 non-packed parameters wins. */
20405 && any_deductions
20408 {
20414 /* We don't count the pack expansion at the end. */
20424 }
20427 }
20429 /* Return the template arguments that will produce the function signature
20430 DECL from the function template FN, with the explicit template
20431 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
20432 also match. Return NULL_TREE if no satisfactory arguments could be
20433 found. */
20435 static tree
20437 {
20441 tree decl_arg_types;
20444 tree arg;
20448 /* Never do unification on the 'this' parameter. */
20469 }
20471 /* Return the innermost template arguments that, when applied to a partial
20472 specialization of TMPL whose innermost template parameters are
20473 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
20474 ARGS.
20476 For example, suppose we have:
20478 template <class T, class U> struct S {};
20479 template <class T> struct S<T*, int> {};
20481 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
20482 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
20483 int}. The resulting vector will be {double}, indicating that `T'
20484 is bound to `double'. */
20486 static tree
20488 {
20490 tree deduced_args;
20491 tree innermost_deduced_args;
20495 {
20499 innermost_deduced_args);
20500 }
20501 else
20514 /* Verify that nondeduced template arguments agree with the type
20515 obtained from argument deduction.
20517 For example:
20519 struct A { typedef int X; };
20520 template <class T, class U> struct C {};
20521 template <class T> struct C<T, typename T::X> {};
20523 Then with the instantiation `C<A, int>', we can deduce that
20524 `T' is `A' but unify () does not check whether `typename T::X'
20525 is `int'. */
20531 /* We only need to check the innermost arguments; the other
20532 arguments will always agree. */
20537 /* Now that we have bindings for all of the template arguments,
20538 ensure that the arguments deduced for the template template
20539 parameters have compatible template parameter lists. See the use
20540 of template_template_parm_bindings_ok_p in fn_type_unification
20541 for more information. */
20546 }
20548 // Compare two function templates T1 and T2 by deducing bindings
20549 // from one against the other. If both deductions succeed, compare
20550 // constraints to see which is more constrained.
20551 static int
20553 {
20558 {
20561 }
20564 {
20567 }
20569 // If both deductions succeed, then one may be more constrained.
20574 }
20576 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
20577 Return the TREE_LIST node with the most specialized template, if
20578 any. If there is no most specialized template, the error_mark_node
20579 is returned.
20581 Note that this function does not look at, or modify, the
20582 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
20583 returned is one of the elements of INSTANTIATIONS, callers may
20584 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
20585 and retrieve it from the value returned. */
20587 tree
20589 {
20596 {
20601 {
20602 /* Equally specialized, move to next function. If there
20603 is no next function, nothing's most specialized. */
20608 }
20609 }
20612 /* Now verify that champ is better than everything earlier in the
20613 instantiation list. */
20616 {
20619 }
20620 }
20622 processing_template_decl--;
20628 }
20630 /* If DECL is a specialization of some template, return the most
20631 general such template. Otherwise, returns NULL_TREE.
20633 For example, given:
20635 template <class T> struct S { template <class U> void f(U); };
20637 if TMPL is `template <class U> void S<int>::f(U)' this will return
20638 the full template. This function will not trace past partial
20639 specializations, however. For example, given in addition:
20641 template <class T> struct S<T*> { template <class U> void f(U); };
20643 if TMPL is `template <class U> void S<int*>::f(U)' this will return
20644 `template <class T> template <class U> S<T*>::f(U)'. */
20646 tree
20648 {
20650 {
20653 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
20654 template friend, or a FIELD_DECL for a capture pack. */
20657 }
20659 /* Look for more and more general templates. */
20661 {
20662 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
20663 (See cp-tree.h for details.) */
20672 /* Stop if we run into an explicitly specialized class template. */
20679 }
20682 }
20684 /* Return the most specialized of the template partial specializations
20685 which can produce TARGET, a specialization of some class or variable
20686 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
20687 a TEMPLATE_DECL node corresponding to the partial specialization, while
20688 the TREE_PURPOSE is the set of template arguments that must be
20689 substituted into the template pattern in order to generate TARGET.
20691 If the choice of partial specialization is ambiguous, a diagnostic
20692 is issued, and the error_mark_node is returned. If there are no
20693 partial specializations matching TARGET, then NULL_TREE is
20694 returned, indicating that the primary template should be used. */
20696 static tree
20698 {
20700 tree t;
20701 tree champ;
20708 {
20712 }
20714 {
20717 }
20719 {
20723 }
20724 else
20729 /* For determining which partial specialization to use, only the
20730 innermost args are interesting. */
20732 {
20735 }
20738 {
20739 tree partial_spec_args;
20740 tree spec_args;
20748 {
20749 /* Discard the outer levels of args, and then substitute in the
20750 template args from the enclosing class. */
20752 partial_spec_args = tsubst_template_args
20755 /* And the same for the partial specialization TEMPLATE_DECL. */
20757 }
20759 partial_spec_args =
20761 partial_spec_args,
20775 partial_spec_args,
20776 args);
20778 {
20782 /* Keep the candidate only if the constraints are satisfied,
20783 or if we're not compiling with concepts. */
20786 {
20789 }
20790 }
20791 }
20801 {
20804 ;
20805 else
20806 {
20808 {
20811 {
20814 }
20815 }
20817 }
20818 }
20822 {
20825 {
20828 }
20829 }
20832 {
20839 else
20843 {
20848 }
20851 }
20854 }
20856 /* Explicitly instantiate DECL. */
20858 void
20860 {
20865 /* An error occurred, for which grokdeclarator has already issued
20866 an appropriate message. */
20869 {
20872 }
20878 {
20879 /* There is an asymmetry here in the way VAR_DECLs and
20880 FUNCTION_DECLs are handled by grokdeclarator. In the case of
20881 the latter, the DECL we get back will be marked as a
20882 template instantiation, and the appropriate
20883 DECL_TEMPLATE_INFO will be set up. This does not happen for
20884 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
20885 should handle VAR_DECLs as it currently handles
20886 FUNCTION_DECLs. */
20888 {
20891 }
20894 {
20897 }
20899 {
20904 }
20905 }
20907 {
20910 }
20911 else
20914 /* Check for various error cases. Note that if the explicit
20915 instantiation is valid the RESULT will currently be marked as an
20916 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
20917 until we get here. */
20920 {
20921 /* DR 259 [temp.spec].
20923 Both an explicit instantiation and a declaration of an explicit
20924 specialization shall not appear in a program unless the explicit
20925 instantiation follows a declaration of the explicit specialization.
20927 For a given set of template parameters, if an explicit
20928 instantiation of a template appears after a declaration of an
20929 explicit specialization for that template, the explicit
20930 instantiation has no effect. */
20932 }
20934 {
20935 /* [temp.spec]
20937 No program shall explicitly instantiate any template more
20938 than once.
20940 We check DECL_NOT_REALLY_EXTERN so as not to complain when
20941 the first instantiation was `extern' and the second is not,
20942 and EXTERN_P for the opposite case. */
20945 /* If an "extern" explicit instantiation follows an ordinary
20946 explicit instantiation, the template is instantiated. */
20949 }
20951 {
20954 }
20956 {
20959 }
20962 ;
20964 {
20967 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
20970 }
20971 else
20979 }
20981 static void
20983 {
20989 {
20992 }
20993 }
20995 /* Called from do_type_instantiation through binding_table_foreach to
20996 do recursive instantiation for the type bound in ENTRY. */
20997 static void
20999 {
21005 }
21007 /* Called from do_type_instantiation to instantiate a member
21008 (a member function or a static member variable) of an
21009 explicitly instantiated class template. */
21010 static void
21012 {
21017 }
21019 /* Perform an explicit instantiation of template class T. STORAGE, if
21020 non-null, is the RID for extern, inline or static. COMPLAIN is
21021 nonzero if this is called from the parser, zero if called recursively,
21022 since the standard is unclear (as detailed below). */
21024 void
21026 {
21036 {
21037 tree tmpl =
21041 else
21044 }
21049 {
21052 t);
21054 }
21057 {
21059 {
21061 {
21064 "ISO C++ 1998 forbids the use of %<extern%> on "
21066 }
21067 else
21069 "ISO C++ forbids the use of %qE"
21071 }
21079 else
21080 {
21082 storage);
21084 }
21085 }
21088 {
21089 /* DR 259 [temp.spec].
21091 Both an explicit instantiation and a declaration of an explicit
21092 specialization shall not appear in a program unless the explicit
21093 instantiation follows a declaration of the explicit specialization.
21095 For a given set of template parameters, if an explicit
21096 instantiation of a template appears after a declaration of an
21097 explicit specialization for that template, the explicit
21098 instantiation has no effect. */
21100 }
21102 {
21103 /* [temp.spec]
21105 No program shall explicitly instantiate any template more
21106 than once.
21108 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
21109 instantiation was `extern'. If EXTERN_P then the second is.
21110 These cases are OK. */
21117 /* If we've already instantiated the template, just return now. */
21120 }
21128 {
21129 tree tmp;
21131 /* In contrast to implicit instantiation, where only the
21132 declarations, and not the definitions, of members are
21133 instantiated, we have here:
21135 [temp.explicit]
21137 The explicit instantiation of a class template specialization
21138 implies the instantiation of all of its members not
21139 previously explicitly specialized in the translation unit
21140 containing the explicit instantiation.
21142 Of course, we can't instantiate member template classes, since
21143 we don't have any arguments for them. Note that the standard
21144 is unclear on whether the instantiation of the members are
21145 *explicit* instantiations or not. However, the most natural
21146 interpretation is that it should be an explicit instantiation. */
21161 }
21162 }
21164 /* Given a function DECL, which is a specialization of TMPL, modify
21165 DECL to be a re-instantiation of TMPL with the same template
21166 arguments. TMPL should be the template into which tsubst'ing
21167 should occur for DECL, not the most general template.
21169 One reason for doing this is a scenario like this:
21171 template <class T>
21172 void f(const T&, int i);
21174 void g() { f(3, 7); }
21176 template <class T>
21177 void f(const T& t, const int i) { }
21179 Note that when the template is first instantiated, with
21180 instantiate_template, the resulting DECL will have no name for the
21181 first parameter, and the wrong type for the second. So, when we go
21182 to instantiate the DECL, we regenerate it. */
21184 static void
21186 {
21187 /* The arguments used to instantiate DECL, from the most general
21188 template. */
21189 tree args;
21190 tree code_pattern;
21195 /* Make sure that we can see identifiers, and compute access
21196 correctly. */
21200 {
21201 tree decl_parm;
21202 tree pattern_parm;
21203 tree specs;
21217 specs);
21219 /* Merge parameter declarations. */
21222 pattern_parm
21226 {
21227 tree parm_type;
21228 tree attributes;
21233 NULL_TREE);
21239 {
21242 }
21245 }
21246 /* Merge any parameters that match with the function parameter
21247 pack. */
21249 {
21251 tree expanded_types;
21252 /* Expand the TYPE_PACK_EXPANSION that provides the types for
21253 the parameters in this function parameter pack. */
21258 {
21259 tree parm_type;
21260 tree attributes;
21263 /* Rename the parameter to include the index. */
21272 {
21275 }
21277 }
21278 }
21279 /* Merge additional specifiers from the CODE_PATTERN. */
21283 }
21285 {
21293 }
21294 else
21298 }
21300 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
21301 substituted to get DECL. */
21303 tree
21305 {
21308 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
21309 for the instantiation. This is not always the most general
21310 template. Consider, for example:
21312 template <class T>
21313 struct S { template <class U> void f();
21314 template <> void f<int>(); };
21316 and an instantiation of S<double>::f<int>. We want TD to be the
21317 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
21319 more general template. */
21321 /* We must also deal with friend templates. Given:
21323 template <class T> struct S {
21324 template <class U> friend void f() {};
21325 };
21327 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
21328 so far as the language is concerned, but that's still
21329 where we get the pattern for the instantiation from. On
21330 other hand, if the definition comes outside the class, say:
21332 template <class T> struct S {
21333 template <class U> friend void f();
21334 };
21335 template <class U> friend void f() {}
21337 we don't need to look any further. That's what the check for
21338 DECL_INITIAL is for. */
21342 {
21343 /* The present template, TD, should not be a definition. If it
21344 were a definition, we should be using it! Note that we
21345 cannot restructure the loop to just keep going until we find
21346 a template with a definition, since that might go too far if
21347 a specialization was declared, but not defined. */
21349 /* Fetch the more general template. */
21351 }
21354 }
21356 /* Returns true if we need to instantiate this template instance even if we
21357 know we aren't going to emit it. */
21359 bool
21361 {
21362 /* We always instantiate inline functions so that we can inline them. An
21363 explicit instantiation declaration prohibits implicit instantiation of
21364 non-inline functions. With high levels of optimization, we would
21365 normally inline non-inline functions -- but we're not allowed to do
21366 that for "extern template" functions. Therefore, we check
21367 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
21371 /* And we need to instantiate static data members so that
21372 their initializers are available in integral constant
21373 expressions. */
21376 }
21378 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
21379 instantiate it now, modifying TREE_TYPE (fn). */
21381 void
21383 {
21386 /* Don't instantiate a noexcept-specification from template context. */
21401 {
21405 {
21420 }
21421 else
21425 }
21428 {
21431 else
21433 }
21434 }
21436 /* Produce the definition of D, a _DECL generated from a template. If
21437 DEFER_OK is nonzero, then we don't have to actually do the
21438 instantiation now; we just have to do it sometime. Normally it is
21439 an error if this is an explicit instantiation but D is undefined.
21440 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
21441 explicitly instantiated class template. */
21443 tree
21446 {
21448 tree gen_args;
21449 tree args;
21450 tree td;
21451 tree code_pattern;
21452 tree spec;
21453 tree gen_tmpl;
21460 tree fn_context;
21463 /* This function should only be used to instantiate templates for
21464 functions and static member variables. */
21467 /* A concept is never instantiated. */
21470 /* Variables are never deferred; if instantiation is required, they
21471 are instantiated right away. That allows for better code in the
21472 case that an expression refers to the value of the variable --
21473 if the variable has a constant value the referring expression can
21474 take advantage of that fact. */
21479 /* Don't instantiate cloned functions. Instead, instantiate the
21480 functions they cloned. */
21488 /* D has already been instantiated or explicitly specialized, so
21489 there's nothing for us to do here.
21491 It might seem reasonable to check whether or not D is an explicit
21492 instantiation, and, if so, stop here. But when an explicit
21493 instantiation is deferred until the end of the compilation,
21494 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
21495 the instantiation. */
21498 /* Check to see whether we know that this template will be
21499 instantiated in some other file, as with "extern template"
21500 extension. */
21503 /* In general, we do not instantiate such templates. */
21511 /* We should already have the extra args. */
21514 /* And what's in the hash table should match D. */
21518 /* This needs to happen before any tsubsting. */
21524 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
21525 for the instantiation. */
21529 /* We should never be trying to instantiate a member of a class
21530 template or partial specialization. */
21535 /* In the case of a friend template whose definition is provided
21536 outside the class, we may have too many arguments. Drop the
21537 ones we don't need. The same is true for specializations. */
21538 args = get_innermost_template_args
21540 else
21544 {
21549 }
21550 else
21551 {
21554 }
21556 /* We may be in the middle of deferred access check. Disable it now. */
21559 /* Unless an explicit instantiation directive has already determined
21560 the linkage of D, remember that a definition is available for
21561 this entity. */
21571 /* If D is a member of an explicitly instantiated class template,
21572 and no definition is available, treat it like an implicit
21573 instantiation. */
21576 {
21577 /* Leave linkage flags alone on instantiations with anonymous
21578 visibility. */
21580 {
21583 }
21585 }
21587 /* Defer all other templates, unless we have been explicitly
21588 forbidden from doing so. */
21590 template. */
21591 ! pattern_defined
21592 /* If it's OK to postpone instantiation, do so. */
21593 || defer_ok
21594 /* If this is a static data member that will be defined
21595 elsewhere, we don't want to instantiate the entire data
21596 member, but we do want to instantiate the initializer so that
21597 we can substitute that elsewhere. */
21599 /* Handle here a deleted function too, avoid generating
21600 its body (c++/61080). */
21602 {
21603 /* The definition of the static data member is now required so
21604 we must substitute the initializer. */
21608 {
21609 tree ns;
21610 tree init;
21619 args,
21622 /* If instantiating the initializer involved instantiating this
21623 again, don't call cp_finish_decl twice. */
21625 {
21626 /* Make sure the initializer is still constant, in case of
21627 circular dependency (template/instantiate6.C). */
21628 const_init
21632 LOOKUP_ONLYCONVERTING);
21633 }
21637 }
21639 /* We restore the source position here because it's used by
21640 add_pending_template. */
21646 /* [temp.explicit]
21648 The definition of a non-exported function template, a
21649 non-exported member function template, or a non-exported
21650 member function or static data member of a class template
21651 shall be present in every translation unit in which it is
21652 explicitly instantiated. */
21656 /* If we're in unevaluated context, we just wanted to get the
21657 constant value; this isn't an odr use, so don't queue
21658 a full instantiation. */
21661 /* ??? Historically, we have instantiated inline functions, even
21662 when marked as "extern template". */
21666 }
21667 /* Tell the repository that D is available in this translation unit
21668 -- and see if it is supposed to be instantiated here. */
21670 {
21671 /* In a PCH file, despite the fact that the repository hasn't
21672 requested instantiation in the PCH it is still possible that
21673 an instantiation will be required in a file that includes the
21674 PCH. */
21677 /* Instantiate inline functions so that the inliner can do its
21678 job, even though we'll not be emitting a copy of this
21679 function. */
21682 }
21692 else
21693 {
21698 }
21700 /* Mark D as instantiated so that recursive calls to
21701 instantiate_decl do not try to instantiate it again. */
21704 /* Regenerate the declaration in case the template has been modified
21705 by a subsequent redeclaration. */
21708 /* We already set the file and line above. Reset them now in case
21709 they changed as a result of calling regenerate_decl_from_template. */
21713 {
21714 tree init;
21717 /* Clear out DECL_RTL; whatever was there before may not be right
21718 since we've reset the type of the declaration. */
21722 /* The initializer is placed in DECL_INITIAL by
21723 regenerate_decl_from_template so we don't need to
21724 push/pop_access_scope again here. Pull it out so that
21725 cp_finish_decl can process it. */
21730 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
21731 initializer. That function will defer actual emission until
21732 we have a chance to determine linkage. */
21735 /* Enter the scope of D so that access-checking works correctly. */
21748 }
21752 {
21754 tree subst_decl;
21755 tree tmpl_parm;
21756 tree spec_parm;
21759 /* Save away the current list, in case we are instantiating one
21760 template from within the body of another. */
21763 /* Set up the list of local specializations. */
21766 /* Set up context. */
21770 else
21773 /* Some typedefs referenced from within the template code need to be
21774 access checked at template instantiation time, i.e now. These
21775 types were added to the template at parsing time. Let's get those
21776 and perform the access checks then. */
21778 gen_args);
21780 /* Create substitution entries for the parameters. */
21785 {
21789 }
21791 {
21793 {
21796 }
21797 else
21798 {
21799 /* Register the (value) argument pack as a specialization of
21800 TMPL_PARM, then move on. */
21803 }
21804 }
21807 /* Substitute into the body of the function. */
21811 else
21812 {
21817 /* Set the current input_location to the end of the function
21818 so that finish_function knows where we are. */
21819 input_location
21822 /* Remember if we saw an infinite loop in the template. */
21823 current_function_infinite_loop
21825 }
21827 /* We don't need the local specializations any more. */
21831 /* Finish the function. */
21835 else
21836 {
21839 }
21843 }
21845 /* We're not deferring instantiation any more. */
21853 out:
21865 }
21867 /* Run through the list of templates that we wish we could
21868 instantiate, and instantiate any we can. RETRIES is the
21869 number of times we retry pending template instantiation. */
21871 void
21873 {
21877 /* Instantiating templates may trigger vtable generation. This in turn
21878 may require further template instantiations. We place a limit here
21879 to avoid infinite loop. */
21881 {
21885 "template instantiation depth exceeds maximum of %d"
21886 " instantiating %q+D, possibly from virtual table generation"
21890 /* Pretend that we defined it. */
21893 }
21895 do
21896 {
21901 {
21906 {
21907 tree fn;
21910 {
21914 fn;
21922 }
21925 }
21926 else
21927 {
21930 {
21931 instantiation
21937 }
21941 }
21944 /* If INSTANTIATION has been instantiated, then we don't
21945 need to consider it again in the future. */
21947 else
21948 {
21951 }
21954 }
21956 }
21960 }
21962 /* Substitute ARGVEC into T, which is a list of initializers for
21963 either base class or a non-static data member. The TREE_PURPOSEs
21964 are DECLs, and the TREE_VALUEs are the initializer values. Used by
21965 instantiate_decl. */
21967 static tree
21969 {
21973 {
21974 tree decl;
21975 tree init;
21981 {
21982 tree expr;
21983 tree arg;
21985 /* Expand the base class expansion type into separate base
21986 classes. */
21988 tf_warning_or_error,
21989 NULL_TREE);
21993 /* We'll be building separate TREE_LISTs of arguments for
21994 each base. */
22000 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
22001 expand each argument in the TREE_VALUE of t. */
22008 /* VOID_TYPE_NODE is used to indicate
22009 value-initialization. */
22010 {
22013 }
22014 else
22015 {
22016 /* Substitute parameter packs into each argument in the
22017 TREE_LIST. */
22020 {
22021 tree expanded_exprs;
22023 /* Expand the argument. */
22025 expanded_exprs
22027 tf_warning_or_error,
22028 NULL_TREE);
22032 /* Prepend each of the expanded expressions to the
22033 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
22035 {
22040 }
22041 }
22044 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
22045 since we built them backwards. */
22047 {
22050 }
22051 }
22052 }
22055 {
22057 {
22061 }
22062 else
22063 {
22064 tree tmp;
22079 /* If we had an initializer but it instantiated to nothing,
22080 value-initialize the object. This will only occur when
22081 the initializer was a pack expansion where the parameter
22082 packs used in that expansion were of length zero. */
22085 }
22088 {
22092 }
22093 }
22094 }
22096 }
22098 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
22100 static void
22102 {
22107 else
22109 }
22111 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
22112 is the instantiation (which should have been created with
22113 start_enum) and ARGS are the template arguments to use. */
22115 static void
22117 {
22118 tree e;
22124 {
22125 tree value;
22126 tree decl;
22129 /* Note that in a template enum, the TREE_VALUE is the
22130 CONST_DECL, not the corresponding INTEGER_CST. */
22135 /* Give this enumeration constant the correct access. */
22138 /* Actually build the enumerator itself. Here we're assuming that
22139 enumerators can't have dependent attributes. */
22142 }
22152 }
22154 /* DECL is a FUNCTION_DECL that is a template specialization. Return
22155 its type -- but without substituting the innermost set of template
22156 arguments. So, innermost set of template parameters will appear in
22157 the type. */
22159 tree
22161 {
22162 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
22164 }
22166 /* Return truthvalue if we're processing a template different from
22167 the last one involved in diagnostics. */
22168 bool
22170 {
22172 }
22174 /* Remember current template involved in diagnostics. */
22175 void
22177 {
22179 }
22183 {
22185 }
22187 /* Return TRUE if current_function_decl is being instantiated, false
22188 otherwise. */
22190 bool
22192 {
22195 }
22197 /* [temp.param] Check that template non-type parm TYPE is of an allowable
22198 type. Return zero for ok, nonzero for disallowed. Issue error and
22199 warning messages under control of COMPLAIN. */
22201 static int
22203 {
22218 /* A bound template template parm could later be instantiated to have a valid
22219 nontype parm type via an alias template. */
22225 {
22228 else
22230 type);
22231 }
22233 }
22235 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
22236 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
22238 static bool
22240 {
22241 tree scope;
22243 /* [temp.dep.type]
22245 A type is dependent if it is:
22247 -- a template parameter. Template template parameters are types
22248 for us (since TYPE_P holds true for them) so we handle
22249 them here. */
22253 /* -- a qualified-id with a nested-name-specifier which contains a
22254 class-name that names a dependent type or whose unqualified-id
22255 names a dependent type. */
22259 /* An alias template specialization can be dependent even if the
22260 resulting type is not. */
22264 /* -- a cv-qualified type where the cv-unqualified type is
22265 dependent.
22266 No code is necessary for this bullet; the code below handles
22267 cv-qualified types, and we don't want to strip aliases with
22268 TYPE_MAIN_VARIANT because of DR 1558. */
22269 /* -- a compound type constructed from any dependent type. */
22279 {
22280 tree arg_type;
22285 arg_type;
22290 }
22291 /* -- an array type constructed from any dependent type or whose
22292 size is specified by a constant expression that is
22293 value-dependent.
22295 We checked for type- and value-dependence of the bounds in
22296 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
22298 {
22303 }
22305 /* -- a template-id in which either the template name is a template
22306 parameter ... */
22309 /* ... or any of the template arguments is a dependent type or
22310 an expression that is type-dependent or value-dependent. */
22312 && (any_dependent_template_arguments_p
22316 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
22317 dependent; if the argument of the `typeof' expression is not
22318 type-dependent, then it should already been have resolved. */
22324 /* A template argument pack is dependent if any of its packed
22325 arguments are. */
22327 {
22333 }
22335 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
22336 be template parameters. */
22340 /* The standard does not specifically mention types that are local
22341 to template functions or local classes, but they should be
22342 considered dependent too. For example:
22344 template <int I> void f() {
22345 enum E { a = I };
22346 S<sizeof (E)> s;
22347 }
22349 The size of `E' cannot be known until the value of `I' has been
22350 determined. Therefore, `E' must be considered dependent. */
22354 /* Don't use type_dependent_expression_p here, as it can lead
22355 to infinite recursion trying to determine whether a lambda
22356 nested in a lambda is dependent (c++/47687). */
22360 && (any_dependent_template_arguments_p
22364 /* Other types are non-dependent. */
22366 }
22368 /* Returns TRUE if TYPE is dependent, in the sense of
22369 [temp.dep.type]. Note that a NULL type is considered dependent. */
22371 bool
22373 {
22374 /* If there are no template parameters in scope, then there can't be
22375 any dependent types. */
22377 {
22378 /* If we are not processing a template, then nobody should be
22379 providing us with a dependent type. */
22383 }
22385 /* If the type is NULL, we have not computed a type for the entity
22386 in question; in that case, the type is dependent. */
22390 /* Erroneous types can be considered non-dependent. */
22394 /* If we have not already computed the appropriate value for TYPE,
22395 do so now. */
22397 {
22400 }
22403 }
22405 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
22406 lookup. In other words, a dependent type that is not the current
22407 instantiation. */
22409 bool
22411 {
22414 }
22416 /* T is a SCOPE_REF; return whether we need to consider it
22417 instantiation-dependent so that we can check access at instantiation
22418 time even though we know which member it resolves to. */
22420 static bool
22422 {
22428 else
22430 }
22432 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
22433 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
22434 expression. */
22436 /* Note that this predicate is not appropriate for general expressions;
22437 only constant expressions (that satisfy potential_constant_expression)
22438 can be tested for value dependence. */
22440 bool
22442 {
22446 /* A name declared with a dependent type. */
22451 {
22453 /* A name that has not been looked up -- must be dependent. */
22457 /* A non-type template parm. */
22461 /* A non-type template parm. */
22467 /* A constant with literal type and is initialized
22468 with an expression that is value-dependent.
22470 Note that a non-dependent parenthesized initializer will have
22471 already been replaced with its constant value, so if we see
22472 a TREE_LIST it must be dependent. */
22476 /* cp_finish_decl doesn't fold reference initializers. */
22487 /* These expressions are value-dependent if the type to which
22488 the cast occurs is dependent or the expression being casted
22489 is value-dependent. */
22490 {
22496 /* A functional cast has a list of operands. */
22499 {
22500 /* If there are no operands, it must be an expression such
22501 as "int()". This should not happen for aggregate types
22502 because it would form non-constant expressions. */
22507 }
22513 }
22518 /* FALLTHRU */
22521 /* A `sizeof' expression is value-dependent if the operand is
22522 type-dependent or is a pack expansion. */
22531 /* An 'encode' expression is value-dependent if the operand is
22532 type-dependent. */
22541 /* All instantiation-dependent expressions should also be considered
22542 value-dependent. */
22550 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
22551 is value-dependent. */
22552 {
22561 }
22564 {
22568 }
22579 {
22583 }
22586 /* Treat all requires-expressions as value-dependent so
22587 we don't try to fold them. */
22594 {
22601 {
22603 /* In a call to a constexpr member function, look through the
22604 implicit ADDR_EXPR on the object argument so that it doesn't
22605 cause the call to be considered value-dependent. We also
22606 look through it in potential_constant_expression. */
22613 }
22615 }
22618 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
22619 type-dependent. */
22624 {
22626 tree val;
22633 }
22636 /* Treat a GNU statement expression as dependent to avoid crashing
22637 under instantiate_non_dependent_expr; it can't be constant. */
22641 /* A constant expression is value-dependent if any subexpression is
22642 value-dependent. */
22644 {
22651 {
22655 {
22658 /* In some cases, some of the operands may be missing.l
22659 (For example, in the case of PREDECREMENT_EXPR, the
22660 amount to increment by may be missing.) That doesn't
22661 make the expression dependent. */
22664 }
22665 }
22669 }
22671 }
22673 /* The expression is not value-dependent. */
22675 }
22677 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
22678 [temp.dep.expr]. Note that an expression with no type is
22679 considered dependent. Other parts of the compiler arrange for an
22680 expression with type-dependent subexpressions to have no type, so
22681 this function doesn't have to be fully recursive. */
22683 bool
22685 {
22692 /* An unresolved name is always dependent. */
22698 /* A fold expression is type-dependent. */
22705 /* Some expression forms are never type-dependent. */
22719 /* The types of these expressions depends only on the type to which
22720 the cast occurs. */
22729 /* The types of these expressions depends only on the type created
22730 by the expression. */
22733 {
22734 /* For NEW_EXPR tree nodes created inside a template, either
22735 the object type itself or a TREE_LIST may appear as the
22736 operand 1. */
22739 /* This is an array type. We need to check array dimensions
22740 as well. */
22742 || value_dependent_expression_p
22744 else
22746 }
22749 {
22753 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
22754 contains an identifier associated by name lookup with one or more
22755 declarations declared with a dependent type, or...a
22756 nested-name-specifier or qualified-id that names a member of an
22757 unknown specialization. */
22760 }
22765 && (any_dependent_template_arguments_p
22777 {
22778 tree elt;
22782 {
22785 }
22787 }
22789 /* A static data member of the current instantiation with incomplete
22790 array type is type-dependent, as the definition and specializations
22791 can have different bounds. */
22798 /* An array of unknown bound depending on a variadic parameter, eg:
22800 template<typename... Args>
22801 void foo (Args... args)
22802 {
22803 int arr[] = { args... };
22804 }
22806 template<int... vals>
22807 void bar ()
22808 {
22809 int arr[] = { vals... };
22810 }
22812 If the array has no length and has an initializer, it must be that
22813 we couldn't determine its length in cp_complete_array_type because
22814 it is dependent. */
22821 /* A variable template specialization is type-dependent if it has any
22822 dependent template arguments. */
22829 /* Always dependent, on the number of arguments if nothing else. */
22834 {
22839 {
22845 }
22846 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
22851 {
22856 }
22859 {
22866 }
22872 {
22876 }
22878 }
22883 }
22885 /* walk_tree callback function for instantiation_dependent_expression_p,
22886 below. Returns non-zero if a dependent subexpression is found. */
22888 static tree
22891 {
22893 {
22894 /* We don't have to worry about decltype currently because decltype
22895 of an instantiation-dependent expr is a dependent type. This
22896 might change depending on the resolution of DR 1172. */
22899 }
22902 {
22903 /* Don't treat an argument list as dependent just because it has no
22904 TREE_TYPE. */
22911 /* A constant with a dependent initializer is dependent. */
22919 /* Handle expressions with type operands. */
22924 {
22929 {
22932 else
22933 {
22936 }
22937 }
22939 }
22949 /* In a template, finish_class_member_access_expr creates a
22950 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
22951 type-dependent, so that we can check access control at
22952 instantiation time (PR 42277). See also Core issue 1273. */
22959 else
22962 /* Treat statement-expressions as dependent. */
22966 /* Treat requires-expressions as dependent. */
22971 /* Treat calls to function concepts as dependent. */
22977 /* And variable concepts. */
22984 }
22988 else
22990 }
22992 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
22993 sense defined by the ABI:
22995 "An expression is instantiation-dependent if it is type-dependent
22996 or value-dependent, or it has a subexpression that is type-dependent
22997 or value-dependent." */
22999 bool
23001 {
23002 tree result;
23013 }
23015 /* Like type_dependent_expression_p, but it also works while not processing
23016 a template definition, i.e. during substitution or mangling. */
23018 bool
23020 {
23026 }
23028 /* Returns TRUE if ARGS contains a type-dependent expression. */
23030 bool
23032 {
23034 tree arg;
23037 {
23040 }
23042 }
23044 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23045 expressions) contains any type-dependent expressions. */
23047 bool
23049 {
23055 }
23057 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
23058 expressions) contains any value-dependent expressions. */
23060 bool
23062 {
23068 }
23070 /* Returns TRUE if the ARG (a template argument) is dependent. */
23072 bool
23074 {
23078 /* Assume a template argument that was wrongly written by the user
23079 is dependent. This is consistent with what
23080 any_dependent_template_arguments_p [that calls this function]
23081 does. */
23092 {
23096 {
23099 }
23102 }
23105 else
23108 }
23110 /* Returns true if ARGS (a collection of template arguments) contains
23111 any types that require structural equality testing. */
23113 bool
23115 {
23125 {
23128 {
23134 {
23135 /* Look inside the argument pack. */
23138 }
23141 {
23154 }
23155 }
23156 }
23159 }
23161 /* Returns true if ARGS (a collection of template arguments) contains
23162 any dependent arguments. */
23164 bool
23166 {
23176 {
23181 }
23184 }
23186 /* Returns TRUE if the template TMPL is dependent. */
23188 bool
23190 {
23192 {
23194 {
23198 }
23200 }
23202 /* Template template parameters are dependent. */
23206 /* So are names that have not been looked up. */
23209 /* So are member templates of dependent classes. */
23213 }
23215 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
23217 bool
23219 {
23222 }
23224 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
23225 are dependent. */
23227 bool
23229 {
23236 {
23258 {
23262 }
23266 {
23270 {
23275 }
23276 }
23277 }
23280 }
23282 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
23283 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
23284 no such TYPE can be found. Note that this function peers inside
23285 uninstantiated templates and therefore should be used only in
23286 extremely limited situations. ONLY_CURRENT_P restricts this
23287 peering to the currently open classes hierarchy (which is required
23288 when comparing types). */
23290 tree
23292 {
23293 tree scope;
23294 tree name;
23295 tree decl;
23297 tree pushed_scope;
23298 tree result;
23303 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
23304 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
23305 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
23306 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
23307 identifier of the TYPENAME_TYPE anymore.
23308 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
23309 TYPENAME_TYPE instead, we avoid messing up with a possible
23310 typedef variant case. */
23313 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
23314 it first before we can figure out what NAME refers to. */
23316 {
23318 /* Given a class template A with a dependent base with nested type C,
23319 typedef typename A::C::C C will land us here, as trying to resolve
23320 the initial A::C leads to the local C typedef, which leads back to
23321 A::C::C. So we break the recursion now. */
23323 else
23325 }
23326 /* If we don't know what SCOPE refers to, then we cannot resolve the
23327 TYPENAME_TYPE. */
23330 /* If the SCOPE is a template type parameter, we have no way of
23331 resolving the name. */
23334 /* If the SCOPE is not the current instantiation, there's no reason
23335 to look inside it. */
23338 /* If this is a typedef, we don't want to look inside (c++/11987). */
23341 /* If SCOPE isn't the template itself, it will not have a valid
23342 TYPE_FIELDS list. */
23345 /* scope is either the template itself or a compatible instantiation
23346 like X<T>, so look up the name in the original template. */
23348 else
23349 /* scope is a partial instantiation, so we can't do the lookup or we
23350 will lose the template arguments. */
23352 /* Enter the SCOPE so that name lookup will be resolved as if we
23353 were in the class definition. In particular, SCOPE will no
23354 longer be considered a dependent type. */
23356 /* Look up the declaration. */
23358 tf_warning_or_error);
23362 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
23363 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
23368 {
23372 }
23375 {
23376 tree tmpl;
23377 tree args;
23378 /* Obtain the template and the arguments. */
23381 /* Instantiate the template. */
23387 }
23389 /* Leave the SCOPE. */
23393 /* If we failed to resolve it, return the original typename. */
23397 /* If lookup found a typename type, resolve that too. */
23399 {
23400 /* Ill-formed programs can cause infinite recursion here, so we
23401 must catch that. */
23405 }
23407 /* Qualify the resulting type. */
23413 }
23415 /* EXPR is an expression which is not type-dependent. Return a proxy
23416 for EXPR that can be used to compute the types of larger
23417 expressions containing EXPR. */
23419 tree
23421 {
23422 tree inner_expr;
23424 /* When checking, try to get a constant value for all non-dependent
23425 expressions in order to expose bugs in *_dependent_expression_p
23426 and constexpr. */
23428 /* Don't do this during nsdmi parsing as it can lead to
23429 unexpected recursive instantiations. */
23433 /* Preserve OVERLOADs; the functions must be available to resolve
23434 types. */
23445 /* There is no need to return a proxy for a variable. */
23448 /* Preserve string constants; conversions from string constants to
23449 "char *" are allowed, even though normally a "const char *"
23450 cannot be used to initialize a "char *". */
23453 /* Preserve void and arithmetic constants, as an optimization -- there is no
23454 reason to create a new node. */
23459 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
23460 There is at least one place where we want to know that a
23461 particular expression is a throw-expression: when checking a ?:
23462 expression, there are special rules if the second or third
23463 argument is a throw-expression. */
23467 /* Don't wrap an initializer list, we need to be able to look inside. */
23471 /* Don't wrap a dummy object, we need to be able to test for it. */
23490 /* If the type is unknown, it can't really be non-dependent */
23493 /* Otherwise, build a NON_DEPENDENT_EXPR. */
23495 }
23497 /* ARGS is a vector of expressions as arguments to a function call.
23498 Replace the arguments with equivalent non-dependent expressions.
23499 This modifies ARGS in place. */
23501 void
23503 {
23505 tree arg;
23508 {
23512 }
23513 }
23515 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
23516 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
23517 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
23519 static tree
23521 {
23535 }
23537 tree
23539 {
23541 }
23543 tree
23545 {
23547 }
23549 /* Make a "constrained auto" type-specifier. This is an
23550 auto type with constraints that must be associated after
23551 deduction. The constraint is formed from the given
23552 CONC and its optional sequence of arguments, which are
23553 non-null if written as partial-concept-id. */
23555 tree
23557 {
23560 /* Build the constraint. */
23562 tree expr;
23565 else
23571 /* Our canonical type depends on the constraint. */
23574 /* Attach the constraint to the type declaration. */
23577 }
23579 /* Given type ARG, return std::initializer_list<ARG>. */
23581 static tree
23583 {
23584 tree std_init_list = namespace_binding
23586 tree argvec;
23588 {
23592 }
23597 }
23599 /* Replace auto in TYPE with std::initializer_list<auto>. */
23601 static tree
23603 {
23610 }
23612 /* Hash traits for hashing possibly constrained 'auto'
23613 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
23616 {
23619 };
23621 /* Hash the 'auto' T. */
23623 inline hashval_t
23625 {
23627 /* Matching constrained-type-specifiers denote the same template
23628 parameter, so hash the constraint. */
23630 else
23631 /* But unconstrained autos are all separate, so just hash the pointer. */
23633 }
23635 /* Compare two 'auto's. */
23639 {
23646 /* Two unconstrained autos are distinct. */
23651 }
23653 /* for_each_template_parm callback for extract_autos: if t is a (possibly
23654 constrained) auto, add it to the vector. */
23656 static int
23658 {
23661 {
23662 /* All the autos were built with index 0; fix that up now. */
23666 /* If this is a repeated constrained-type-specifier, use the index we
23667 chose before. */
23669 else
23670 {
23671 /* Otherwise this is new, so use the current count. */
23674 }
23676 }
23678 /* Always keep walking. */
23680 }
23682 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
23683 says they can appear anywhere in the type. */
23685 static tree
23687 {
23696 {
23701 }
23704 }
23706 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
23707 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
23709 tree
23711 {
23713 tf_warning_or_error,
23714 adc_unspecified);
23715 }
23717 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
23718 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
23719 The CONTEXT determines the context in which auto deduction is performed
23720 and is used to control error diagnostics. */
23722 tree
23725 {
23726 tree targs;
23732 /* Defining a subset of type-dependent expressions that we can deduce
23733 from ahead of time isn't worth the trouble. */
23736 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
23737 with either a new invented type template parameter U or, if the
23738 initializer is a braced-init-list (8.5.4), with
23739 std::initializer_list<U>. */
23741 {
23746 else
23747 {
23749 {
23753 "for deduction to %<std::initializer_list%>, use copy-"
23755 }
23757 }
23758 }
23766 {
23773 {
23777 }
23778 }
23779 else
23780 {
23782 tree tparms;
23786 else
23787 {
23791 }
23798 {
23800 /* Try again at instantiation time. */
23804 /* If type is error_mark_node a diagnostic must have been
23805 emitted by now. Also, having a mention to '<type error>'
23806 in the diagnostic is not really useful to the user. */
23807 {
23811 else
23816 }
23818 }
23819 }
23821 /* Check any placeholder constraints against the deduced type. */
23824 {
23825 /* Use the deduced type to check the associated constraints. */
23827 {
23829 {
23831 {
23847 }
23849 }
23851 }
23852 }
23857 }
23859 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
23860 result. */
23862 tree
23864 {
23866 {
23872 /* In an abbreviated function template we didn't know we were dealing
23873 with a function template when we saw the auto return type, so update
23874 it to have the correct level. */
23876 }
23878 }
23880 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
23881 'decltype(auto)'. */
23883 bool
23885 {
23890 else
23892 }
23894 /* for_each_template_parm callback for type_uses_auto. */
23896 int
23898 {
23900 }
23902 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
23903 a use of `auto'. Returns NULL_TREE otherwise. */
23905 tree
23907 {
23911 {
23912 /* The Concepts TS allows multiple autos in one type-specifier; just
23913 return the first one we find, do_auto_deduction will collect all of
23914 them. */
23918 else
23920 }
23921 else
23923 }
23925 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
23926 'decltype(auto)' or a concept. */
23928 bool
23930 {
23932 }
23934 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
23935 a concept identifier) iff TYPE contains a use of a generic type. Returns
23936 NULL_TREE otherwise. */
23938 tree
23940 {
23942 }
23945 /* For a given template T, return the vector of typedefs referenced
23946 in T for which access check is needed at T instantiation time.
23947 T is either a FUNCTION_DECL or a RECORD_TYPE.
23948 Those typedefs were added to T by the function
23949 append_type_to_template_for_access_check. */
23953 {
23954 tree ti;
23965 {
23970 }
23973 }
23975 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
23976 tied to T. That list of typedefs will be access checked at
23977 T instantiation time.
23978 T is either a FUNCTION_DECL or a RECORD_TYPE.
23979 TYPE_DECL is a TYPE_DECL node representing a typedef.
23980 SCOPE is the scope through which TYPE_DECL is accessed.
23981 LOCATION is the location of the usage point of TYPE_DECL.
23983 This function is a subroutine of
23984 append_type_to_template_for_access_check. */
23986 static void
23988 tree type_decl,
23989 tree scope,
23990 location_t location)
23991 {
23992 qualified_typedef_usage_t typedef_usage;
23993 tree ti;
24000 && type_decl
24014 }
24016 /* Append TYPE_DECL to the template TEMPL.
24017 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
24018 At TEMPL instanciation time, TYPE_DECL will be checked to see
24019 if it can be accessed through SCOPE.
24020 LOCATION is the location of the usage point of TYPE_DECL.
24022 e.g. consider the following code snippet:
24024 class C
24025 {
24026 typedef int myint;
24027 };
24029 template<class U> struct S
24030 {
24031 C::myint mi; // <-- usage point of the typedef C::myint
24032 };
24034 S<char> s;
24036 At S<char> instantiation time, we need to check the access of C::myint
24037 In other words, we need to check the access of the myint typedef through
24038 the C scope. For that purpose, this function will add the myint typedef
24039 and the scope C through which its being accessed to a list of typedefs
24040 tied to the template S. That list will be walked at template instantiation
24041 time and access check performed on each typedefs it contains.
24042 Note that this particular code snippet should yield an error because
24043 myint is private to C. */
24045 void
24047 tree type_decl,
24048 tree scope,
24049 location_t location)
24050 {
24056 /* Make sure we don't append the type to the template twice. */
24063 }
24065 /* Convert the generic type parameters in PARM that match the types given in the
24066 range [START_IDX, END_IDX) from the current_template_parms into generic type
24067 packs. */
24069 tree
24071 {
24082 {
24083 /* Create a distinct parameter pack type from the current parm and add it
24084 to the replacement args to tsubst below into the generic function
24085 parameter. */
24100 }
24106 /* If there are more levels then build up the replacement with the outer
24107 template parms. */
24111 replacement);
24114 }
24116 /* Entries in the decl_constraint hash table. */
24118 {
24119 tree decl;
24120 tree ci;
24121 };
24123 /* Hashing function and equality for constraint entries. */
24125 {
24127 {
24129 }
24132 {
24134 }
24135 };
24137 /* A mapping from declarations to constraint information. Note that
24138 both templates and their underlying declarations are mapped to the
24139 same constraint information.
24141 FIXME: This is defined in pt.c because garbage collection
24142 code is not being generated for constraint.cc. */
24146 /* Returns true iff cinfo contains a valid set of constraints.
24147 This is the case when the associated requirements have been
24148 successfully decomposed into lists of atomic constraints.
24149 That is, when the saved assumptions are not error_mark_node. */
24151 bool
24153 {
24156 }
24158 /* Returns the template constraints of declaration T. If T is not
24159 constrained, return NULL_TREE. Note that T must be non-null. */
24161 tree
24163 {
24171 else
24173 }
24175 /* Associate the given constraint information CI with the declaration
24176 T. If T is a template, then the constraints are associated with
24177 its underlying declaration. Don't build associations if CI is
24178 NULL_TREE. */
24180 void
24182 {
24194 }
24196 /* Remove the associated constraints of the declaration T. */
24198 void
24200 {
24209 }
24211 /* Set up the hash table for constraint association. */
24213 void
24215 {
24217 }
24219 /* Set up the hash tables for template instantiations. */
24221 void
24223 {
24226 }
24228 /* Print stats about the template hash tables for -fstats. */
24230 void
24232 {
24241 }