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1 /* Handle parameterized types (templates) for GNU C++.
2 Copyright (C) 1992-2014 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". */
51 /* The type of functions taking a tree, and some additional data, and
52 returning an int. */
55 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
56 instantiations have been deferred, either because their definitions
57 were not yet available, or because we were putting off doing the work. */
61 };
76 /* Live only within one (recursive) call to tsubst_expr. We use
77 this to pass the statement expression node from the STMT_EXPR
78 to the EXPR_STMT that is its result. */
81 /* A map from local variable declarations in the body of the template
82 presently being instantiated to the corresponding instantiated
83 local variables. */
86 /* True if we've recursed into fn_type_unification too many times. */
90 {
91 tree tmpl;
92 tree args;
93 tree spec;
97 htab_t decl_specializations;
100 htab_t type_specializations;
102 /* Contains canonical template parameter types. The vector is indexed by
103 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
104 TREE_LIST, whose TREE_VALUEs contain the canonical template
105 parameters of various types and levels. */
108 #define UNIFY_ALLOW_NONE 0
109 #define UNIFY_ALLOW_MORE_CV_QUAL 1
110 #define UNIFY_ALLOW_LESS_CV_QUAL 2
111 #define UNIFY_ALLOW_DERIVED 4
112 #define UNIFY_ALLOW_INTEGER 8
113 #define UNIFY_ALLOW_OUTER_LEVEL 16
114 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
115 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
118 tbr_incomplete_type,
119 tbr_ambiguous_baseclass,
120 tbr_success
121 };
144 tree);
207 location_t);
215 /* Make the current scope suitable for access checking when we are
216 processing T. T can be FUNCTION_DECL for instantiated function
217 template, VAR_DECL for static member variable, or TYPE_DECL for
218 alias template (needed by instantiate_decl). */
220 static void
222 {
230 else
234 {
235 saved_access_scope = tree_cons
238 }
239 }
241 /* Restore the scope set up by push_access_scope. T is the node we
242 are processing. */
244 static void
246 {
248 {
251 }
255 else
257 }
259 /* Do any processing required when DECL (a member template
260 declaration) is finished. Returns the TEMPLATE_DECL corresponding
261 to DECL, unless it is a specialization, in which case the DECL
262 itself is returned. */
264 tree
266 {
273 {
274 tree type;
282 {
286 }
288 }
292 {
294 {
297 }
298 else
300 }
301 else
305 }
307 /* Create a template info node. */
309 tree
311 {
316 }
318 /* Return the template info node corresponding to T, whatever T is. */
320 tree
322 {
340 }
342 /* Returns the template nesting level of the indicated class TYPE.
344 For example, in:
345 template <class T>
346 struct A
347 {
348 template <class U>
349 struct B {};
350 };
352 A<T>::B<U> has depth two, while A<T> has depth one.
353 Both A<T>::B<int> and A<int>::B<U> have depth one, if
354 they are instantiations, not specializations.
356 This function is guaranteed to return 0 if passed NULL_TREE so
357 that, for example, `template_class_depth (current_class_type)' is
358 always safe. */
360 int
362 {
369 {
375 }
378 }
380 /* Subroutine of maybe_begin_member_template_processing.
381 Returns true if processing DECL needs us to push template parms. */
383 static bool
385 {
391 }
393 /* Subroutine of maybe_begin_member_template_processing.
394 Push the template parms in PARMS, starting from LEVELS steps into the
395 chain, and ending at the beginning, since template parms are listed
396 innermost first. */
398 static void
400 {
408 current_template_parms
414 NULL);
416 {
425 {
432 {
433 /* Make a CONST_DECL as is done in process_template_parm.
434 It is ugly that we recreate this here; the original
435 version built in process_template_parm is no longer
436 available. */
446 }
451 }
452 }
453 }
455 /* Restore the template parameter context for a member template, a
456 friend template defined in a class definition, or a non-template
457 member of template class. */
459 void
461 {
462 tree parms;
472 {
477 {
480 }
483 }
485 /* Remember how many levels of template parameters we pushed so that
486 we can pop them later. */
488 }
490 /* Undo the effects of maybe_begin_member_template_processing. */
492 void
494 {
503 {
507 }
508 }
510 /* Return a new template argument vector which contains all of ARGS,
511 but has as its innermost set of arguments the EXTRA_ARGS. */
513 static tree
515 {
516 tree new_args;
534 }
536 /* Like add_to_template_args, but only the outermost ARGS are added to
537 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
538 (EXTRA_ARGS) levels are added. This function is used to combine
539 the template arguments from a partial instantiation with the
540 template arguments used to attain the full instantiation from the
541 partial instantiation. */
543 static tree
545 {
546 tree new_args;
548 /* If there are more levels of EXTRA_ARGS than there are ARGS,
549 something very fishy is going on. */
552 /* If *all* the new arguments will be the EXTRA_ARGS, just return
553 them. */
557 /* For the moment, we make ARGS look like it contains fewer levels. */
562 /* Now, we restore ARGS to its full dimensions. */
566 }
568 /* Return the N levels of innermost template arguments from the ARGS. */
570 tree
572 {
573 tree new_args;
579 /* If N is 1, just return the innermost set of template arguments. */
583 /* If we're not removing anything, just return the arguments we were
584 given. */
590 /* Make a new set of arguments, not containing the outer arguments. */
597 }
599 /* The inverse of get_innermost_template_args: Return all but the innermost
600 EXTRA_LEVELS levels of template arguments from the ARGS. */
602 static tree
604 {
605 tree new_args;
611 /* If N is 1, just return the outermost set of template arguments. */
615 /* If we're not removing anything, just return the arguments we were
616 given. */
621 /* Make a new set of arguments, not containing the inner arguments. */
628 }
630 /* We've got a template header coming up; push to a new level for storing
631 the parms. */
633 void
635 {
636 /* We use a non-tag-transparent scope here, which causes pushtag to
637 put tags in this scope, rather than in the enclosing class or
638 namespace scope. This is the right thing, since we want
639 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
640 global template class, push_template_decl handles putting the
641 TEMPLATE_DECL into top-level scope. For a nested template class,
642 e.g.:
644 template <class T> struct S1 {
645 template <class T> struct S2 {};
646 };
648 pushtag contains special code to call pushdecl_with_scope on the
649 TEMPLATE_DECL for S2. */
654 }
656 /* This routine is called when a specialization is declared. If it is
657 invalid to declare a specialization here, an error is reported and
658 false is returned, otherwise this routine will return true. */
660 static bool
662 {
665 /* [temp.expl.spec]
667 An explicit specialization shall be declared in the namespace of
668 which the template is a member, or, for member templates, in the
669 namespace of which the enclosing class or enclosing class
670 template is a member. An explicit specialization of a member
671 function, member class or static data member of a class template
672 shall be declared in the namespace of which the class template
673 is a member. */
675 {
678 }
680 /* [temp.expl.spec]
682 In an explicit specialization declaration for a member of a class
683 template or a member template that appears in namespace scope,
684 the member template and some of its enclosing class templates may
685 remain unspecialized, except that the declaration shall not
686 explicitly specialize a class member template if its enclosing
687 class templates are not explicitly specialized as well. */
689 {
692 }
695 }
697 /* We've just seen template <>. */
699 bool
701 {
705 }
707 /* Called at then end of processing a declaration preceded by
708 template<>. */
710 void
712 {
715 }
717 /* Any template <>'s that we have seen thus far are not referring to a
718 function specialization. */
720 void
722 {
725 }
727 /* We've just seen a template header. If SPECIALIZATION is nonzero,
728 it was of the form template <>. */
730 static void
732 {
734 template_header_count++;
735 }
737 /* We're beginning an explicit instantiation. */
739 void
741 {
744 }
747 void
749 {
752 }
754 /* An explicit specialization or partial specialization of TMPL is being
755 declared. Check that the namespace in which the specialization is
756 occurring is permissible. Returns false iff it is invalid to
757 specialize TMPL in the current namespace. */
759 static bool
761 {
764 /* [tmpl.expl.spec]
766 An explicit specialization shall be declared in the namespace of
767 which the template is a member, or, for member templates, in the
768 namespace of which the enclosing class or enclosing class
769 template is a member. An explicit specialization of a member
770 function, member class or static data member of a class template
771 shall be declared in the namespace of which the class template is
772 a member. */
775 {
778 }
780 /* Same or super-using namespace. */
782 else
783 {
787 }
788 }
790 /* SPEC is an explicit instantiation. Check that it is valid to
791 perform this explicit instantiation in the current namespace. */
793 static void
795 {
796 tree ns;
798 /* DR 275: An explicit instantiation shall appear in an enclosing
799 namespace of its template. */
805 }
807 /* The TYPE is being declared. If it is a template type, that means it
808 is a partial specialization. Do appropriate error-checking. */
810 tree
812 {
813 tree context;
818 /* A lambda that appears in specialization context is not itself a
819 specialization. */
824 {
828 }
833 {
838 else
841 }
843 {
844 /* This is for ordinary explicit specialization and partial
845 specialization of a template class such as:
847 template <> class C<int>;
849 or:
851 template <class T> class C<T*>;
853 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
857 {
862 {
866 }
867 }
873 /* Trying to define a specialization either without a template<> header
874 or in an inappropriate place. We've already given an error, so just
875 bail now so we don't actually define the specialization. */
877 }
883 {
884 /* This is for an explicit specialization of member class
885 template according to [temp.expl.spec/18]:
887 template <> template <class U> class C<int>::D;
889 The context `C<int>' must be an implicit instantiation.
890 Otherwise this is just a member class template declared
891 earlier like:
893 template <> class C<int> { template <class U> class D; };
894 template <> template <class U> class C<int>::D;
896 In the first case, `C<int>::D' is a specialization of `C<T>::D'
897 while in the second case, `C<int>::D' is a primary template
898 and `C<T>::D' may not exist. */
902 {
903 tree t;
908 {
911 }
913 /* Check for invalid specialization after instantiation:
915 template <> template <> class C<int>::D<int>;
916 template <> template <class U> class C<int>::D; */
920 {
923 {
924 /* We already have a full specialization of this partial
925 instantiation. Reassign it to the new member
926 specialization template. */
927 spec_entry elt;
944 }
946 /* But if we've had an implicit instantiation, that's a
947 problem ([temp.expl.spec]/6). */
950 }
952 /* Mark TYPE as a specialization. And as a result, we only
953 have one level of template argument for the innermost
954 class template. */
959 }
960 }
962 {
963 /* Someday C++0x may allow for enum template specialization. */
968 else
969 {
972 }
973 }
976 }
978 /* Returns nonzero if we can optimize the retrieval of specializations
979 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
980 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
984 {
987 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
988 parameter. */
990 /* The optimized lookup depends on the fact that the
991 template arguments for the member function template apply
992 purely to the containing class, which is not true if the
993 containing class is an explicit or partial
994 specialization. */
998 /* It is possible to have a template that is not a member
999 template and is not a member of a template class:
1001 template <typename T>
1002 struct S { friend A::f(); };
1004 Here, the friend function is a template, but the context does
1005 not have template information. The optimized lookup relies
1006 on having ARGS be the template arguments for both the class
1007 and the function template. */
1009 }
1011 /* Retrieve the specialization (in the sense of [temp.spec] - a
1012 specialization is either an instantiation or an explicit
1013 specialization) of TMPL for the given template ARGS. If there is
1014 no such specialization, return NULL_TREE. The ARGS are a vector of
1015 arguments, or a vector of vectors of arguments, in the case of
1016 templates with more than one level of parameters.
1018 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1019 then we search for a partial specialization matching ARGS. This
1020 parameter is ignored if TMPL is not a class template.
1022 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1023 result is a NONTYPE_ARGUMENT_PACK. */
1025 static tree
1027 {
1037 /* There should be as many levels of arguments as there are
1038 levels of parameters. */
1045 {
1046 tree class_template;
1047 tree class_specialization;
1049 tree fns;
1052 /* The template arguments actually apply to the containing
1053 class. Find the class specialization with those
1054 arguments. */
1056 class_specialization
1060 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1061 for the specialization. */
1065 /* Iterate through the methods with the indicated name, looking
1066 for the one that has an instance of TMPL. */
1069 {
1072 /* using-declarations can add base methods to the method vec,
1073 and we don't want those here. */
1076 }
1078 }
1079 else
1080 {
1082 spec_entry elt;
1083 htab_t specializations;
1091 else
1099 }
1102 }
1104 /* Like retrieve_specialization, but for local declarations. */
1106 static tree
1108 {
1116 }
1118 /* Returns nonzero iff DECL is a specialization of TMPL. */
1120 int
1122 {
1123 tree t;
1126 {
1132 }
1133 else
1134 {
1143 }
1146 }
1148 /* Returns nonzero iff DECL is a specialization of friend declaration
1149 FRIEND_DECL according to [temp.friend]. */
1151 bool
1153 {
1160 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1161 of a template class, we want to check if DECL is a specialization
1162 if this. */
1166 {
1167 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1170 }
1175 /* There is nothing to do if this is not a template friend. */
1182 /* [temp.friend/6]
1183 A member of a class template may be declared to be a friend of a
1184 non-template class. In this case, the corresponding member of
1185 every specialization of the class template is a friend of the
1186 class granting friendship.
1188 For example, given a template friend declaration
1190 template <class T> friend void A<T>::f();
1192 the member function below is considered a friend
1194 template <> struct A<int> {
1195 void f();
1196 };
1198 For this type of template friend, TEMPLATE_DEPTH below will be
1199 nonzero. To determine if DECL is a friend of FRIEND, we first
1200 check if the enclosing class is a specialization of another. */
1207 {
1208 /* Next, we check the members themselves. In order to handle
1209 a few tricky cases, such as when FRIEND_DECL's are
1211 template <class T> friend void A<T>::g(T t);
1212 template <class T> template <T t> friend void A<T>::h();
1214 and DECL's are
1216 void A<int>::g(int);
1217 template <int> void A<int>::h();
1219 we need to figure out ARGS, the template arguments from
1220 the context of DECL. This is required for template substitution
1221 of `T' in the function parameter of `g' and template parameter
1222 of `h' in the above examples. Here ARGS corresponds to `int'. */
1229 {
1231 {
1234 else
1236 current_depth++;
1237 }
1239 }
1242 {
1244 tree friend_type;
1245 tree decl_type;
1246 tree friend_args_type;
1247 tree decl_args_type;
1249 /* Make sure that both DECL and FRIEND_DECL are templates or
1250 non-templates. */
1256 {
1257 /* If both are templates, check template parameter list. */
1258 tree friend_parms
1263 friend_parms))
1267 }
1268 else
1276 /* Check if return types match. */
1280 /* Check if function parameter types match, ignoring the
1281 `this' parameter. */
1290 }
1291 else
1292 {
1293 /* DECL is a TYPE_DECL */
1297 /* Make sure that both DECL and FRIEND_DECL are templates or
1298 non-templates. */
1299 is_template
1306 {
1307 tree friend_parms;
1308 /* If both are templates, check the name of the two
1309 TEMPLATE_DECL's first because is_friend didn't. */
1314 /* Now check template parameter list. */
1315 friend_parms
1318 return comp_template_parms
1320 friend_parms);
1321 }
1322 else
1325 }
1326 }
1328 }
1330 /* Register the specialization SPEC as a specialization of TMPL with
1331 the indicated ARGS. IS_FRIEND indicates whether the specialization
1332 is actually just a friend declaration. Returns SPEC, or an
1333 equivalent prior declaration, if available.
1335 We also store instantiations of field packs in the hash table, even
1336 though they are not themselves templates, to make lookup easier. */
1338 static tree
1340 hashval_t hash)
1341 {
1342 tree fn;
1344 spec_entry elt;
1352 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1353 register it; we want the corresponding TEMPLATE_DECL instead.
1354 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1355 the more obvious `uses_template_parms (spec)' to avoid problems
1356 with default function arguments. In particular, given
1357 something like this:
1359 template <class T> void f(T t1, T t = T())
1361 the default argument expression is not substituted for in an
1362 instantiation unless and until it is actually needed. */
1366 /* We don't put these specializations in the hash table, but we might
1367 want to give an error about a mismatch. */
1369 else
1370 {
1378 slot =
1382 else
1384 }
1386 /* We can sometimes try to re-register a specialization that we've
1387 already got. In particular, regenerate_decl_from_template calls
1388 duplicate_decls which will update the specialization list. But,
1389 we'll still get called again here anyhow. It's more convenient
1390 to simply allow this than to try to prevent it. */
1394 {
1396 {
1399 {
1401 fn);
1403 }
1404 else
1405 {
1406 tree clone;
1407 /* This situation should occur only if the first
1408 specialization is an implicit instantiation, the
1409 second is an explicit specialization, and the
1410 implicit instantiation has not yet been used. That
1411 situation can occur if we have implicitly
1412 instantiated a member function and then specialized
1413 it later.
1415 We can also wind up here if a friend declaration that
1416 looked like an instantiation turns out to be a
1417 specialization:
1419 template <class T> void foo(T);
1420 class S { friend void foo<>(int) };
1421 template <> void foo(int);
1423 We transform the existing DECL in place so that any
1424 pointers to it become pointers to the updated
1425 declaration.
1427 If there was a definition for the template, but not
1428 for the specialization, we want this to look as if
1429 there were no definition, and vice versa. */
1432 /* The call to duplicate_decls will have applied
1433 [temp.expl.spec]:
1435 An explicit specialization of a function template
1436 is inline only if it is explicitly declared to be,
1437 and independently of whether its function template
1438 is.
1440 to the primary function; now copy the inline bits to
1441 the various clones. */
1443 {
1448 }
1452 }
1453 }
1455 {
1457 /* Dup decl failed, but this is a new definition. Set the
1458 line number so any errors match this new
1459 definition. */
1463 }
1464 }
1468 /* A specialization must be declared in the same namespace as the
1469 template it is specializing. */
1475 {
1483 /* TMPL is a forward declaration of a template function; keep a list
1484 of all specializations in case we need to reassign them to a friend
1485 template later in tsubst_friend_function. */
1488 }
1491 }
1493 /* Returns true iff two spec_entry nodes are equivalent. Only compares the
1494 TMPL and ARGS members, ignores SPEC. */
1498 static int
1500 {
1511 }
1513 /* Returns a hash for a template TMPL and template arguments ARGS. */
1515 static hashval_t
1517 {
1520 }
1522 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1523 ignoring SPEC. */
1525 static hashval_t
1527 {
1530 }
1532 /* Recursively calculate a hash value for a template argument ARG, for use
1533 in the hash tables of template specializations. */
1535 hashval_t
1537 {
1549 /* We can get one of these when re-hashing a previous entry in the middle
1550 of substituting into a pack expansion. Just look through it. */
1559 {
1567 {
1572 }
1594 {
1597 {
1600 }
1602 }
1606 {
1609 }
1620 val = iterative_hash_template_arg
1632 val);
1634 val);
1643 /* A lambda can't appear in a template arg, but don't crash on
1644 erroneous input. */
1656 /* Now hash operands as usual. */
1661 }
1664 {
1668 val);
1671 /* Otherwise just compare the types during lookup. */
1680 {
1685 }
1686 }
1689 }
1691 /* Unregister the specialization SPEC as a specialization of TMPL.
1692 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1693 if the SPEC was listed as a specialization of TMPL.
1695 Note that SPEC has been ggc_freed, so we can't look inside it. */
1697 bool
1699 {
1701 spec_entry elt;
1709 {
1714 }
1717 }
1719 /* Like register_specialization, but for local declarations. We are
1720 registering SPEC, an instantiation of TMPL. */
1722 static void
1724 {
1729 }
1731 /* TYPE is a class type. Returns true if TYPE is an explicitly
1732 specialized class. */
1734 bool
1736 {
1740 }
1742 /* Print the list of functions at FNS, going through all the overloads
1743 for each element of the list. Alternatively, FNS can not be a
1744 TREE_LIST, in which case it will be printed together with all the
1745 overloads.
1747 MORE and *STR should respectively be FALSE and NULL when the function
1748 is called from the outside. They are used internally on recursive
1749 calls. print_candidates manages the two parameters and leaves NULL
1750 in *STR when it ends. */
1752 static void
1754 {
1760 {
1764 }
1765 else
1766 {
1769 {
1770 /* Pick the prefix string. */
1772 {
1776 }
1780 }
1783 }
1786 {
1789 }
1790 }
1792 /* Print the list of candidate FNS in an error message. FNS can also
1793 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1795 void
1797 {
1801 }
1803 /* Returns the template (one of the functions given by TEMPLATE_ID)
1804 which can be specialized to match the indicated DECL with the
1805 explicit template args given in TEMPLATE_ID. The DECL may be
1806 NULL_TREE if none is available. In that case, the functions in
1807 TEMPLATE_ID are non-members.
1809 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1810 specialization of a member template.
1812 The TEMPLATE_COUNT is the number of references to qualifying
1813 template classes that appeared in the name of the function. See
1814 check_explicit_specialization for a more accurate description.
1816 TSK indicates what kind of template declaration (if any) is being
1817 declared. TSK_TEMPLATE indicates that the declaration given by
1818 DECL, though a FUNCTION_DECL, has template parameters, and is
1819 therefore a template function.
1821 The template args (those explicitly specified and those deduced)
1822 are output in a newly created vector *TARGS_OUT.
1824 If it is impossible to determine the result, an error message is
1825 issued. The error_mark_node is returned to indicate failure. */
1827 static tree
1829 tree decl,
1833 tmpl_spec_kind tsk)
1834 {
1835 tree fns;
1836 tree targs;
1837 tree explicit_targs;
1839 /* A TREE_LIST of templates of which DECL may be a specialization.
1840 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1841 corresponding TREE_PURPOSE is the set of template arguments that,
1842 when used to instantiate the template, would produce a function
1843 with the signature of DECL. */
1853 /* We shouldn't be specializing a member template of an
1854 unspecialized class template; we already gave an error in
1855 check_specialization_scope, now avoid crashing. */
1858 {
1861 }
1869 /* Check for baselinks. */
1874 {
1877 }
1879 /* Count the number of template headers specified for this
1880 specialization. */
1888 {
1892 {
1893 tree decl_arg_types;
1894 tree fn_arg_types;
1895 tree insttype;
1897 /* In case of explicit specialization, we need to check if
1898 the number of template headers appearing in the specialization
1899 is correct. This is usually done in check_explicit_specialization,
1900 but the check done there cannot be exhaustive when specializing
1901 member functions. Consider the following code:
1903 template <> void A<int>::f(int);
1904 template <> template <> void A<int>::f(int);
1906 Assuming that A<int> is not itself an explicit specialization
1907 already, the first line specializes "f" which is a non-template
1908 member function, whilst the second line specializes "f" which
1909 is a template member function. So both lines are syntactically
1910 correct, and check_explicit_specialization does not reject
1911 them.
1913 Here, we can do better, as we are matching the specialization
1914 against the declarations. We count the number of template
1915 headers, and we check if they match TEMPLATE_COUNT + 1
1916 (TEMPLATE_COUNT is the number of qualifying template classes,
1917 plus there must be another header for the member template
1918 itself).
1920 Notice that if header_count is zero, this is not a
1921 specialization but rather a template instantiation, so there
1922 is no check we can perform here. */
1926 /* Check that the number of template arguments at the
1927 innermost level for DECL is the same as for FN. */
1935 /* DECL might be a specialization of FN. */
1939 /* For a non-static member function, we need to make sure
1940 that the const qualification is the same. Since
1941 get_bindings does not try to merge the "this" parameter,
1942 we must do the comparison explicitly. */
1948 /* Skip the "this" parameter and, for constructors of
1949 classes with virtual bases, the VTT parameter. A
1950 full specialization of a constructor will have a VTT
1951 parameter, but a template never will. */
1952 decl_arg_types
1954 fn_arg_types
1957 /* Function templates cannot be specializations; there are
1958 no partial specializations of functions. Therefore, if
1959 the type of DECL does not match FN, there is no
1960 match. */
1962 {
1966 }
1968 /* See whether this function might be a specialization of this
1969 template. Suppress access control because we might be trying
1970 to make this specialization a friend, and we have already done
1971 access control for the declaration of the specialization. */
1977 /* We cannot deduce template arguments that when used to
1978 specialize TMPL will produce DECL. */
1981 /* Make sure that the deduced arguments actually work. */
1985 fn_arg_types
1990 /* Save this template, and the arguments deduced. */
1992 }
1994 /* FN is an ordinary member function, and we need a
1995 specialization of a member template. */
1996 ;
1998 /* We can get IDENTIFIER_NODEs here in certain erroneous
1999 cases. */
2000 ;
2002 /* This is just an ordinary non-member function. Nothing can
2003 be a specialization of that. */
2004 ;
2006 /* Cannot specialize functions that are created implicitly. */
2007 ;
2008 else
2009 {
2010 tree decl_arg_types;
2012 /* This is an ordinary member function. However, since
2013 we're here, we can assume its enclosing class is a
2014 template class. For example,
2016 template <typename T> struct S { void f(); };
2017 template <> void S<int>::f() {}
2019 Here, S<int>::f is a non-template, but S<int> is a
2020 template class. If FN has the same type as DECL, we
2021 might be in business. */
2024 /* Its enclosing class is an explicit specialization
2025 of a template class. This is not a candidate. */
2030 /* The return types differ. */
2033 /* Adjust the type of DECL in case FN is a static member. */
2040 decl_arg_types))
2041 /* They match! */
2043 }
2044 }
2047 {
2048 /* We have:
2050 [temp.expl.spec]
2052 It is possible for a specialization with a given function
2053 signature to be instantiated from more than one function
2054 template. In such cases, explicit specification of the
2055 template arguments must be used to uniquely identify the
2056 function template specialization being specialized.
2058 Note that here, there's no suggestion that we're supposed to
2059 determine which of the candidate templates is most
2060 specialized. However, we, also have:
2062 [temp.func.order]
2064 Partial ordering of overloaded function template
2065 declarations is used in the following contexts to select
2066 the function template to which a function template
2067 specialization refers:
2069 -- when an explicit specialization refers to a function
2070 template.
2072 So, we do use the partial ordering rules, at least for now.
2073 This extension can only serve to make invalid programs valid,
2074 so it's safe. And, there is strong anecdotal evidence that
2075 the committee intended the partial ordering rules to apply;
2076 the EDG front end has that behavior, and John Spicer claims
2077 that the committee simply forgot to delete the wording in
2078 [temp.expl.spec]. */
2081 {
2084 }
2085 }
2088 {
2096 }
2100 {
2106 }
2108 /* We have one, and exactly one, match. */
2110 {
2113 /* DECL is a re-declaration or partial instantiation of a template
2114 function. */
2117 /* It was a specialization of an ordinary member function in a
2118 template class. */
2120 }
2122 /* It was a specialization of a template. */
2125 {
2130 }
2131 else
2134 }
2136 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2137 but with the default argument values filled in from those in the
2138 TMPL_TYPES. */
2140 static tree
2142 tree tmpl_types)
2143 {
2144 tree new_spec_types;
2152 /* Substitute into the rest of the list. */
2153 new_spec_types =
2157 /* Add the default argument for this parameter. */
2160 new_spec_types);
2161 }
2163 /* DECL is an explicit specialization. Replicate default arguments
2164 from the template it specializes. (That way, code like:
2166 template <class T> void f(T = 3);
2167 template <> void f(double);
2168 void g () { f (); }
2170 works, as required.) An alternative approach would be to look up
2171 the correct default arguments at the call-site, but this approach
2172 is consistent with how implicit instantiations are handled. */
2174 static void
2176 {
2177 tree tmpl;
2178 tree spec_types;
2179 tree tmpl_types;
2180 tree new_spec_types;
2181 tree old_type;
2182 tree new_type;
2183 tree t;
2188 /* See if there's anything we need to do. */
2201 {
2202 /* Remove the this pointer, but remember the object's type for
2203 CV quals. */
2209 {
2210 /* DECL may contain more parameters than TMPL due to the extra
2211 in-charge parameter in constructors and destructors. */
2214 }
2216 {
2219 }
2220 }
2222 /* Compute the merged default arguments. */
2223 new_spec_types =
2226 /* Compute the new FUNCTION_TYPE. */
2228 {
2232 new_spec_types);
2235 /* Put the in-charge parameter back. */
2238 new_spec_types);
2242 new_spec_types);
2243 }
2244 else
2246 new_spec_types);
2252 }
2254 /* Return the number of template headers we expect to see for a definition
2255 or specialization of CTYPE or one of its non-template members. */
2257 int
2259 {
2263 {
2264 /* You're supposed to have one `template <...>' for every
2265 template class, but you don't need one for a full
2266 specialization. For example:
2268 template <class T> struct S{};
2269 template <> struct S<int> { void f(); };
2270 void S<int>::f () {}
2272 is correct; there shouldn't be a `template <>' for the
2273 definition of `S<int>::f'. */
2275 /* If CTYPE does not have template information of any
2276 kind, then it is not a template, nor is it nested
2277 within a template. */
2285 }
2288 }
2290 /* Do a simple sanity check on the template headers that precede the
2291 variable declaration DECL. */
2293 void
2295 {
2302 {
2308 "members of an explicitly specialized class are defined "
2310 }
2311 }
2313 /* Check to see if the function just declared, as indicated in
2314 DECLARATOR, and in DECL, is a specialization of a function
2315 template. We may also discover that the declaration is an explicit
2316 instantiation at this point.
2318 Returns DECL, or an equivalent declaration that should be used
2319 instead if all goes well. Issues an error message if something is
2320 amiss. Returns error_mark_node if the error is not easily
2321 recoverable.
2323 FLAGS is a bitmask consisting of the following flags:
2325 2: The function has a definition.
2326 4: The function is a friend.
2328 The TEMPLATE_COUNT is the number of references to qualifying
2329 template classes that appeared in the name of the function. For
2330 example, in
2332 template <class T> struct S { void f(); };
2333 void S<int>::f();
2335 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2336 classes are not counted in the TEMPLATE_COUNT, so that in
2338 template <class T> struct S {};
2339 template <> struct S<int> { void f(); }
2340 template <> void S<int>::f();
2342 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2343 invalid; there should be no template <>.)
2345 If the function is a specialization, it is marked as such via
2346 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2347 is set up correctly, and it is added to the list of specializations
2348 for that template. */
2350 tree
2352 tree decl,
2355 {
2363 tmpl_spec_kind tsk;
2366 {
2369 else
2371 }
2372 else
2376 {
2379 {
2382 }
2384 {
2386 /* This could be something like:
2388 template <class T> void f(T);
2389 class S { friend void f<>(int); } */
2391 else
2392 {
2393 /* This case handles bogus declarations like template <>
2394 template <class T> void f<int>(); */
2397 declarator);
2399 }
2400 }
2404 /* The error has already been reported in
2405 check_specialization_scope. */
2411 /* Fall through. */
2424 decl);
2427 else
2431 /* Fall through. */
2436 else
2442 {
2443 /* This case handles bogus declarations like template <>
2444 template <class T> void f<int>(); */
2449 else
2451 declarator);
2453 }
2456 /* This is a specialization of a member template, without
2457 specialization the containing class. Something like:
2459 template <class T> struct S {
2460 template <class U> void f (U);
2461 };
2462 template <> template <class U> void S<int>::f(U) {}
2464 That's a specialization -- but of the entire template. */
2470 }
2473 {
2477 {
2481 }
2482 }
2485 {
2489 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2491 {
2492 tree fns;
2497 else
2498 {
2499 /* If there is no class context, the explicit instantiation
2500 must be at namespace scope. */
2503 /* Find the namespace binding, using the declaration
2504 context. */
2508 {
2511 }
2512 else
2513 {
2519 }
2520 }
2523 }
2529 {
2531 /* A specialization in class scope. This is invalid,
2532 but the error will already have been flagged by
2533 check_specialization_scope. */
2535 else
2536 {
2537 /* It's not valid to write an explicit instantiation in
2538 class scope, e.g.:
2540 class C { template void f(); }
2542 This case is caught by the parser. However, on
2543 something like:
2545 template class C { void f(); };
2547 (which is invalid) we can get here. The error will be
2548 issued later. */
2549 ;
2550 }
2553 }
2556 {
2557 /* Find the list of functions in ctype that have the same
2558 name as the declared function. */
2564 {
2569 {
2570 /* From [temp.expl.spec]:
2572 If such an explicit specialization for the member
2573 of a class template names an implicitly-declared
2574 special member function (clause _special_), the
2575 program is ill-formed.
2577 Similar language is found in [temp.explicit]. */
2580 }
2583 }
2586 {
2590 }
2591 else
2592 {
2594 tree ovl;
2596 /* For a type-conversion operator, we cannot do a
2597 name-based lookup. We might be looking for `operator
2598 int' which will be a specialization of `operator T'.
2599 So, we find *all* the conversion operators, and then
2600 select from them. */
2608 {
2610 /* There are no more conversion functions. */
2613 /* Glue all these conversion functions together
2614 with those we already have. */
2617 }
2618 }
2621 {
2624 }
2625 else
2627 }
2629 /* Figure out what exactly is being specialized at this point.
2630 Note that for an explicit instantiation, even one for a
2631 member function, we cannot tell apriori whether the
2632 instantiation is for a member template, or just a member
2633 function of a template class. Even if a member template is
2634 being instantiated, the member template arguments may be
2635 elided if they can be deduced from the rest of the
2636 declaration. */
2639 member_specialization,
2640 template_count,
2641 tsk);
2644 /* We couldn't figure out what this declaration was
2645 specializing. */
2647 else
2648 {
2652 {
2653 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2654 is done by do_decl_instantiation later. */
2660 {
2661 /* If TMPL is not the most general template (for
2662 example, if TMPL is a friend template that is
2663 injected into namespace scope), then there will
2664 be too many levels of TARGS. Remove some of them
2665 here. */
2667 tree new_targs;
2674 }
2677 }
2679 /* If we thought that the DECL was a member function, but it
2680 turns out to be specializing a static member function,
2681 make DECL a static member function as well. */
2686 /* If this is a specialization of a member template of a
2687 template class, we want to return the TEMPLATE_DECL, not
2688 the specialization of it. */
2690 {
2695 {
2696 tree parm;
2700 /* We want to use the argument list specified in the
2701 definition, not in the original declaration. */
2706 }
2709 }
2711 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2714 /* Inherit default function arguments from the template
2715 DECL is specializing. */
2718 /* This specialization has the same protection as the
2719 template it specializes. */
2723 /* 7.1.1-1 [dcl.stc]
2725 A storage-class-specifier shall not be specified in an
2726 explicit specialization...
2728 The parser rejects these, so unless action is taken here,
2729 explicit function specializations will always appear with
2730 global linkage.
2732 The action recommended by the C++ CWG in response to C++
2733 defect report 605 is to make the storage class and linkage
2734 of the explicit specialization match the templated function:
2736 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2737 */
2739 {
2743 /* This specialization has the same linkage and visibility as
2744 the function template it specializes. */
2747 {
2750 }
2753 {
2756 }
2757 }
2759 /* If DECL is a friend declaration, declared using an
2760 unqualified name, the namespace associated with DECL may
2761 have been set incorrectly. For example, in:
2763 template <typename T> void f(T);
2764 namespace N {
2765 struct S { friend void f<int>(int); }
2766 }
2768 we will have set the DECL_CONTEXT for the friend
2769 declaration to N, rather than to the global namespace. */
2774 /* This is not really a declaration of a specialization.
2775 It's just the name of an instantiation. But, it's not
2776 a request for an instantiation, either. */
2779 /* This is indeed a specialization. In case of constructors
2780 and destructors, we need in-charge and not-in-charge
2781 versions in V3 ABI. */
2784 /* Register this specialization so that we can find it
2785 again. */
2787 }
2788 }
2791 }
2793 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2794 parameters. These are represented in the same format used for
2795 DECL_TEMPLATE_PARMS. */
2797 int
2799 {
2800 const_tree p1;
2801 const_tree p2;
2809 {
2821 {
2825 /* If either of the template parameters are invalid, assume
2826 they match for the sake of error recovery. */
2839 }
2840 }
2843 /* One set of parameters has more parameters lists than the
2844 other. */
2848 }
2850 /* Determine whether PARM is a parameter pack. */
2852 bool
2854 {
2855 /* Determine if we have a non-type template parameter pack. */
2862 /* If this is a list of template parameters, we could get a
2863 TYPE_DECL or a TEMPLATE_DECL. */
2867 /* Otherwise it must be a type template parameter. */
2871 }
2873 /* Determine if T is a function parameter pack. */
2875 bool
2877 {
2881 }
2883 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
2884 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
2886 tree
2888 {
2895 }
2897 /* Return true iff the function parameter PARAM_DECL was expanded
2898 from the function parameter pack PACK. */
2900 bool
2902 {
2907 /* The parameter pack and its pack arguments have the same
2908 DECL_PARM_INDEX. */
2910 }
2912 /* Determine whether ARGS describes a variadic template args list,
2913 i.e., one that is terminated by a template argument pack. */
2915 static bool
2917 {
2919 tree last_parm;
2933 }
2935 /* Generate a new name for the parameter pack name NAME (an
2936 IDENTIFIER_NODE) that incorporates its */
2938 static tree
2940 {
2941 /* Munge the name to include the parameter index. */
2942 #define NUMBUF_LEN 128
2956 }
2958 /* Return true if T is a primary function, class or alias template
2959 instantiation. */
2961 bool
2963 {
2977 }
2979 /* Return true if PARM is a template template parameter. */
2981 bool
2983 {
2985 }
2987 /* Return true iff PARM is a DECL representing a type template
2988 parameter. */
2990 bool
2992 {
2997 }
2999 /* Return the template parameters of T if T is a
3000 primary template instantiation, NULL otherwise. */
3002 tree
3004 {
3009 parms = INNERMOST_TEMPLATE_PARMS
3013 }
3015 /* Return the template parameters of the LEVELth level from the full list
3016 of template parameters PARMS. */
3018 tree
3020 {
3021 tree p;
3032 }
3034 /* Returns the template arguments of T if T is a template instantiation,
3035 NULL otherwise. */
3037 tree
3039 {
3047 }
3049 /* Return the argument pack elements of T if T is a template argument pack,
3050 NULL otherwise. */
3052 tree
3054 {
3060 }
3062 /* Structure used to track the progress of find_parameter_packs_r. */
3063 struct find_parameter_pack_data
3064 {
3065 /* TREE_LIST that will contain all of the parameter packs found by
3066 the traversal. */
3069 /* Set of AST nodes that have been visited by the traversal. */
3071 };
3073 /* Identifies all of the argument packs that occur in a template
3074 argument and appends them to the TREE_LIST inside DATA, which is a
3075 find_parameter_pack_data structure. This is a subroutine of
3076 make_pack_expansion and uses_parameter_packs. */
3077 static tree
3079 {
3085 /* Handle type aliases/typedefs. */
3087 {
3094 }
3096 /* Identify whether this is a parameter pack or not. */
3098 {
3114 {
3115 /* We don't want to walk into the type of a PARM_DECL,
3116 because we don't want to see the type parameter pack. */
3119 }
3122 /* Look through a lambda capture proxy to the field pack. */
3125 {
3131 }
3138 /* Not a parameter pack. */
3140 }
3143 {
3144 /* Add this parameter pack to the list. */
3146 }
3152 /* This switch statement will return immediately if we don't find a
3153 parameter pack. */
3155 {
3160 /* Check the template itself. */
3163 /* Check the template arguments. */
3179 /* Fall through. */
3221 }
3224 }
3226 /* Determines if the expression or type T uses any parameter packs. */
3227 bool
3229 {
3237 }
3239 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3240 representation a base-class initializer into a parameter pack
3241 expansion. If all goes well, the resulting node will be an
3242 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3243 respectively. */
3244 tree
3246 {
3247 tree result;
3256 {
3257 /* The only time we will see a TREE_LIST here is for a base
3258 class initializer. In this case, the TREE_PURPOSE will be a
3259 _TYPE node (representing the base class expansion we're
3260 initializing) and the TREE_VALUE will be a TREE_LIST
3261 containing the initialization arguments.
3263 The resulting expansion looks somewhat different from most
3264 expansions. Rather than returning just one _EXPANSION, we
3265 return a TREE_LIST whose TREE_PURPOSE is a
3266 TYPE_PACK_EXPANSION containing the bases that will be
3267 initialized. The TREE_VALUE will be identical to the
3268 original TREE_VALUE, which is a list of arguments that will
3269 be passed to each base. We do not introduce any new pack
3270 expansion nodes into the TREE_VALUE (although it is possible
3271 that some already exist), because the TREE_PURPOSE and
3272 TREE_VALUE all need to be expanded together with the same
3273 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3274 resulting TREE_PURPOSE will mention the parameter packs in
3275 both the bases and the arguments to the bases. */
3276 tree purpose;
3277 tree value;
3280 /* Determine which parameter packs will be used by the base
3281 class expansion. */
3288 {
3292 }
3295 {
3296 /* Collect the sets of parameter packs used in each of the
3297 initialization arguments. */
3299 {
3300 /* Determine which parameter packs will be expanded in this
3301 argument. */
3304 }
3305 }
3309 /* Create the pack expansion type for the base type. */
3314 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3315 they will rarely be compared to anything. */
3319 }
3324 /* Build the PACK_EXPANSION_* node. */
3325 result = for_types
3330 {
3331 /* Propagate type and const-expression information. */
3334 }
3335 else
3336 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3337 they will rarely be compared to anything. */
3340 /* Determine which parameter packs will be expanded. */
3346 /* Make sure we found some parameter packs. */
3348 {
3351 else
3354 }
3360 }
3362 /* Checks T for any "bare" parameter packs, which have not yet been
3363 expanded, and issues an error if any are found. This operation can
3364 only be done on full expressions or types (e.g., an expression
3365 statement, "if" condition, etc.), because we could have expressions like:
3367 foo(f(g(h(args)))...)
3369 where "args" is a parameter pack. check_for_bare_parameter_packs
3370 should not be called for the subexpressions args, h(args),
3371 g(h(args)), or f(g(h(args))), because we would produce erroneous
3372 error messages.
3374 Returns TRUE and emits an error if there were bare parameter packs,
3375 returns FALSE otherwise. */
3376 bool
3378 {
3394 {
3397 {
3406 else
3411 else
3415 }
3418 }
3421 }
3423 /* Expand any parameter packs that occur in the template arguments in
3424 ARGS. */
3425 tree
3427 {
3433 /* First, determine if we need to expand anything, and the number of
3434 slots we'll need. */
3436 {
3441 {
3445 else
3447 }
3448 else
3449 {
3451 num_result_args++;
3452 }
3453 }
3455 /* If no expansion is necessary, we're done. */
3459 /* Expand arguments. */
3462 non_default_args_count =
3465 {
3468 {
3475 }
3476 else
3477 {
3480 }
3481 }
3485 }
3487 /* Checks if DECL shadows a template parameter.
3489 [temp.local]: A template-parameter shall not be redeclared within its
3490 scope (including nested scopes).
3492 Emits an error and returns TRUE if the DECL shadows a parameter,
3493 returns FALSE otherwise. */
3495 bool
3497 {
3498 tree olddecl;
3500 /* If we're not in a template, we can't possibly shadow a template
3501 parameter. */
3505 /* Figure out what we're shadowing. */
3510 /* If there's no previous binding for this name, we're not shadowing
3511 anything, let alone a template parameter. */
3515 /* If we're not shadowing a template parameter, we're done. Note
3516 that OLDDECL might be an OVERLOAD (or perhaps even an
3517 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3518 node. */
3522 /* We check for decl != olddecl to avoid bogus errors for using a
3523 name inside a class. We check TPFI to avoid duplicate errors for
3524 inline member templates. */
3533 }
3535 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3536 ORIG_LEVEL, DECL, and TYPE. */
3538 static tree
3542 tree decl,
3543 tree type)
3544 {
3555 }
3557 /* Find the canonical type parameter for the given template type
3558 parameter. Returns the canonical type parameter, which may be TYPE
3559 if no such parameter existed. */
3561 static tree
3563 {
3564 tree list;
3578 else
3579 {
3584 }
3585 }
3587 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3588 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3589 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3590 new one is created. */
3592 static tree
3594 tsubst_flags_t complain)
3595 {
3600 {
3619 /* Template template parameters need this. */
3624 }
3627 }
3629 /* Process information from new template parameter PARM and append it
3630 to the LIST being built. This new parameter is a non-type
3631 parameter iff IS_NON_TYPE is true. This new parameter is a
3632 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3633 is in PARM_LOC. NUM_TEMPLATE_PARMS is the size of the template
3634 parameter list PARM belongs to. This is used used to create a
3635 proper canonical type for the type of PARM that is to be created,
3636 iff PARM is a type. If the size is not known, this parameter shall
3637 be set to 0. */
3639 tree
3642 {
3644 tree defval;
3645 tree err_parm_list;
3652 {
3656 {
3660 else
3662 }
3665 }
3666 else
3670 {
3676 {
3680 }
3681 else
3682 {
3683 /* [temp.param]
3685 The top-level cv-qualifiers on the template-parameter are
3686 ignored when determining its type. */
3689 {
3693 }
3696 {
3697 /* This template parameter is not a parameter pack, but it
3698 should be. Complain about "bare" parameter packs. */
3701 /* Recover by calling this a parameter pack. */
3703 }
3704 }
3706 /* A template parameter is not modifiable. */
3715 processing_template_decl,
3720 }
3721 else
3722 {
3723 tree t;
3727 {
3729 /* This is for distinguishing between real templates and template
3730 template parameters */
3734 }
3735 else
3736 {
3738 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3741 }
3748 processing_template_decl,
3752 }
3758 }
3760 /* The end of a template parameter list has been reached. Process the
3761 tree list into a parameter vector, converting each parameter into a more
3762 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3763 as PARM_DECLs. */
3765 tree
3767 {
3772 current_template_parms
3777 {
3781 }
3786 }
3788 /* end_template_decl is called after a template declaration is seen. */
3790 void
3792 {
3798 /* This matches the pushlevel in begin_template_parm_list. */
3803 }
3805 /* Takes a TREE_LIST representing a template parameter and convert it
3806 into an argument suitable to be passed to the type substitution
3807 functions. Note that If the TREE_LIST contains an error_mark
3808 node, the returned argument is error_mark_node. */
3810 static tree
3812 {
3825 {
3829 {
3830 /* Turn this argument into a TYPE_ARGUMENT_PACK
3831 with a single element, which expands T. */
3833 #ifdef ENABLE_CHECKING
3834 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3836 #endif
3841 }
3842 }
3843 else
3844 {
3848 {
3849 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3850 with a single element, which expands T. */
3853 #ifdef ENABLE_CHECKING
3854 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3856 #endif
3862 }
3863 }
3865 }
3867 /* Given a set of template parameters, return them as a set of template
3868 arguments. The template parameters are represented as a TREE_VEC, in
3869 the form documented in cp-tree.h for template arguments. */
3871 static tree
3873 {
3874 tree header;
3879 /* If there is only one level of template parameters, we do not
3880 create a TREE_VEC of TREE_VECs. Instead, we return a single
3881 TREE_VEC containing the arguments. */
3886 {
3894 #ifdef ENABLE_CHECKING
3896 #endif
3900 else
3902 }
3905 /* This can happen for template parms of a template template
3906 parameter, e.g:
3908 template<template<class T, class U> class TT> struct S;
3910 Consider the level of the parms of TT; T and U both have
3911 level 2; TT has no template parm of level 1. So in this case
3912 the first element of full_template_args is NULL_TREE. If we
3913 leave it like this TMPL_ARGS_DEPTH on args returns 1 instead
3914 of 2. This will make tsubst wrongly consider that T and U
3915 have level 1. Instead, let's create a dummy vector as the
3916 first element of full_template_args so that TMPL_ARGS_DEPTH
3917 returns the correct depth for args. */
3920 }
3922 /* Within the declaration of a template, return the currently active
3923 template parameters as an argument TREE_VEC. */
3925 static tree
3927 {
3929 }
3931 /* Update the declared TYPE by doing any lookups which were thought to be
3932 dependent, but are not now that we know the SCOPE of the declarator. */
3934 tree
3936 {
3947 /* Don't bother building up the args in this case. */
3949 {
3950 /* tsubst in the args corresponding to the template parameters,
3951 including auto if present. Most things will be unchanged, but
3952 make_typename_type and tsubst_qualified_id will resolve
3953 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
3956 tree pushed;
3958 {
3962 }
3967 }
3973 {
3976 else
3978 }
3980 }
3982 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
3983 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
3984 a member template. Used by push_template_decl below. */
3986 static tree
3988 {
3996 }
3998 struct template_parm_data
3999 {
4000 /* The level of the template parameters we are currently
4001 processing. */
4004 /* The index of the specialization argument we are currently
4005 processing. */
4008 /* An array whose size is the number of template parameters. The
4009 elements are nonzero if the parameter has been used in any one
4010 of the arguments processed so far. */
4013 /* An array whose size is the number of template arguments. The
4014 elements are nonzero if the argument makes use of template
4015 parameters of this level. */
4017 };
4019 /* Subroutine of push_template_decl used to see if each template
4020 parameter in a partial specialization is used in the explicit
4021 argument list. If T is of the LEVEL given in DATA (which is
4022 treated as a template_parm_data*), then DATA->PARMS is marked
4023 appropriately. */
4025 static int
4027 {
4033 {
4036 }
4037 else
4038 {
4041 }
4044 {
4047 }
4049 /* Return zero so that for_each_template_parm will continue the
4050 traversal of the tree; we want to mark *every* template parm. */
4052 }
4054 /* Process the partial specialization DECL. */
4056 static tree
4058 {
4064 tree inner_parms;
4065 tree inst;
4078 /* We check that each of the template parameters given in the
4079 partial specialization is used in the argument list to the
4080 specialization. For example:
4082 template <class T> struct S;
4083 template <class T> struct S<T*>;
4085 The second declaration is OK because `T*' uses the template
4086 parameter T, whereas
4088 template <class T> struct S<int>;
4090 is no good. Even trickier is:
4092 template <class T>
4093 struct S1
4094 {
4095 template <class U>
4096 struct S2;
4097 template <class U>
4098 struct S2<T>;
4099 };
4101 The S2<T> declaration is actually invalid; it is a
4102 full-specialization. Of course,
4104 template <class U>
4105 struct S2<T (*)(U)>;
4107 or some such would have been OK. */
4115 {
4120 NULL,
4122 }
4125 {
4126 /* One of the template parms was not used in the
4127 specialization. */
4129 {
4132 }
4135 }
4140 /* [temp.class.spec]
4142 The argument list of the specialization shall not be identical to
4143 the implicit argument list of the primary template. */
4150 /* A partial specialization that replaces multiple parameters of the
4151 primary template with a pack expansion is less specialized for those
4152 parameters. */
4154 {
4156 "primary template because it replaces multiple parameters "
4160 }
4162 /* [temp.class.spec]
4164 A partially specialized non-type argument expression shall not
4165 involve template parameters of the partial specialization except
4166 when the argument expression is a simple identifier.
4168 The type of a template parameter corresponding to a specialized
4169 non-type argument shall not be dependent on a parameter of the
4170 specialization.
4172 Also, we verify that pack expansions only occur at the
4173 end of the argument list. */
4177 {
4184 {
4185 /* Extract the arguments from the argument pack. We'll be
4186 iterating over these in the following loop. */
4189 }
4192 {
4194 /* Get the Jth argument in the parameter pack. */
4198 {
4199 /* Pack expansions must come at the end of the
4200 argument list. */
4203 {
4207 else
4210 }
4211 }
4214 /* We only care about the pattern. */
4220 /* This next line is the `argument expression is not just a
4221 simple identifier' condition and also the `specialized
4222 non-type argument' bit. */
4224 {
4228 arg);
4229 else
4230 {
4231 /* Look at the corresponding template parameter,
4232 marking which template parameters its type depends
4233 upon. */
4237 {
4238 /* We haven't yet initialized TPD2. Do so now. */
4240 /* The number of parameters here is the number in the
4241 main template, which, as checked in the assertion
4242 above, is NARGS. */
4246 }
4248 /* Mark the template parameters. But this time, we're
4249 looking for the template parameters of the main
4250 template, not in the specialization. */
4257 NULL,
4261 {
4262 /* The type depended on some template parameters.
4263 If they are fully specialized in the
4264 specialization, that's OK. */
4273 "type %qT of template argument %qE depends "
4275 "type %qT of template argument %qE depends "
4277 type,
4278 arg);
4279 }
4280 }
4281 }
4282 }
4283 }
4285 /* We should only get here once. */
4303 {
4307 {
4311 "partial specialization of %qT after instantiation "
4313 }
4314 }
4317 }
4319 /* Check that a template declaration's use of default arguments and
4320 parameter packs is not invalid. Here, PARMS are the template
4321 parameters. IS_PRIMARY is true if DECL is the thing declared by
4322 a primary template. IS_PARTIAL is true if DECL is a partial
4323 specialization.
4325 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4326 declaration (but not a definition); 1 indicates a declaration, 2
4327 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4328 emitted for extraneous default arguments.
4330 Returns TRUE if there were no errors found, FALSE otherwise. */
4332 bool
4335 {
4338 tree parm_level;
4341 /* [temp.param]
4343 A default template-argument shall not be specified in a
4344 function template declaration or a function template definition, nor
4345 in the template-parameter-list of the definition of a member of a
4346 class template. */
4349 /* You can't have a function template declaration in a local
4350 scope, nor you can you define a member of a class template in a
4351 local scope. */
4357 /* A lambda doesn't have an explicit declaration; don't complain
4358 about the parms of the enclosing class. */
4365 /* If this is either a friend defined in the scope of the class
4366 or a member function. */
4372 /* And, if it was a member function, it really was defined in
4373 the scope of the class. */
4376 /* We already checked these parameters when the template was
4377 declared, so there's no need to do it again now. This function
4378 was defined in class scope, but we're processing its body now
4379 that the class is complete. */
4382 /* Core issue 226 (C++0x only): the following only applies to class
4383 templates. */
4386 {
4387 /* [temp.param]
4389 If a template-parameter has a default template-argument, all
4390 subsequent template-parameters shall have a default
4391 template-argument supplied. */
4393 {
4400 {
4410 {
4412 /* For better subsequent error-recovery, we indicate that
4413 there should have been a default argument. */
4416 }
4418 && !is_friend_decl
4419 /* Don't complain about an enclosing partial
4420 specialization. */
4425 {
4426 /* A primary class template can only have one
4427 parameter pack, at the end of the template
4428 parameter list. */
4433 else
4441 }
4442 }
4443 }
4444 }
4447 || is_partial
4448 || !is_primary
4450 /* For an ordinary class template, default template arguments are
4451 allowed at the innermost level, e.g.:
4452 template <class T = int>
4453 struct S {};
4454 but, in a partial specialization, they're not allowed even
4455 there, as we have in [temp.class.spec]:
4457 The template parameter list of a specialization shall not
4458 contain default template argument values.
4460 So, for a partial specialization, or for a function template
4461 (in C++98/C++03), we look at all of them. */
4462 ;
4463 else
4464 /* But, for a primary class template that is not a partial
4465 specialization we look at all template parameters except the
4466 innermost ones. */
4469 /* Figure out what error message to issue. */
4482 else
4486 /* If we're inside a class definition, there's no need to
4487 examine the parameters to the class itself. On the one
4488 hand, they will be checked when the class is defined, and,
4489 on the other, default arguments are valid in things like:
4490 template <class T = double>
4491 struct S { template <class U> void f(U); };
4492 Here the default argument for `S' has no bearing on the
4493 declaration of `f'. */
4495 else
4496 /* Check everything. */
4502 {
4509 {
4514 {
4516 {
4523 }
4525 /* Clear out the default argument so that we are not
4526 confused later. */
4528 }
4529 }
4531 /* At this point, if we're still interested in issuing messages,
4532 they must apply to classes surrounding the object declared. */
4536 }
4539 }
4541 /* Worker for push_template_decl_real, called via
4542 for_each_template_parm. DATA is really an int, indicating the
4543 level of the parameters we are interested in. If T is a template
4544 parameter of that level, return nonzero. */
4546 static int
4548 {
4554 else
4557 }
4559 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
4560 parameters given by current_template_args, or reuses a
4561 previously existing one, if appropriate. Returns the DECL, or an
4562 equivalent one, if it is replaced via a call to duplicate_decls.
4564 If IS_FRIEND is true, DECL is a friend declaration. */
4566 tree
4568 {
4569 tree tmpl;
4570 tree args;
4571 tree info;
4572 tree ctx;
4576 /* True if the template is a member template, in the sense of
4577 [temp.mem]. */
4583 /* See if this is a partial specialization. */
4592 /* For a friend, we want the context of the friend function, not
4593 the type of which it is a friend. */
4597 /* In the case of a virtual function, we want the class in which
4598 it is defined. */
4600 else
4601 /* Otherwise, if we're currently defining some class, the DECL
4602 is assumed to be a member of the class. */
4611 /* See if this is a primary template. */
4613 /* A friend template that specifies a class context, i.e.
4614 template <typename T> friend void A<T>::f();
4615 is not primary. */
4617 else
4621 {
4626 {
4629 }
4631 {
4633 {
4634 /* [temp.mem]
4636 A destructor shall not be a member template. */
4639 }
4646 {
4647 /* [basic.stc.dynamic.allocation]
4649 An allocation function can be a function
4650 template. ... Template allocation functions shall
4651 have two or more parameters. */
4654 }
4655 }
4661 /* alias-declaration */
4663 else
4664 {
4667 }
4668 }
4670 /* Check to see that the rules regarding the use of default
4671 arguments are not being violated. */
4675 /* Ensure that there are no parameter packs in the type of this
4676 declaration that have not been expanded. */
4678 {
4679 /* Check each of the arguments individually to see if there are
4680 any bare parameter packs. */
4686 {
4689 {
4690 /* This is a PARM_DECL that contains unexpanded parameter
4691 packs. We have already complained about this in the
4692 check_for_bare_parameter_packs call, so just replace
4693 these types with ERROR_MARK_NODE. */
4696 }
4700 }
4702 /* Check for bare parameter packs in the return type and the
4703 exception specifiers. */
4705 /* Errors were already issued, set return type to int
4706 as the frontend doesn't expect error_mark_node as
4707 the return type. */
4711 }
4716 {
4719 }
4732 {
4737 /* If DECL is a TYPE_DECL for a class-template, then there won't
4738 be DECL_LANG_SPECIFIC. The information equivalent to
4739 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
4743 {
4744 /* Since a template declaration already existed for this
4745 class-type, we must be redeclaring it here. Make sure
4746 that the redeclaration is valid. */
4748 current_template_parms);
4749 /* We don't need to create a new TEMPLATE_DECL; just use the
4750 one we already had. */
4752 }
4753 else
4754 {
4756 member_template_p);
4761 {
4762 /* A specialization of a member template of a template
4763 class. */
4767 }
4768 }
4769 }
4770 else
4771 {
4777 {
4780 }
4788 {
4789 tree new_tmpl;
4791 /* The declaration is a specialization of a member
4792 template, declared outside the class. Therefore, the
4793 innermost template arguments will be NULL, so we
4794 replace them with the arguments determined by the
4795 earlier call to check_explicit_specialization. */
4798 new_tmpl
4800 member_template_p);
4810 args,
4813 }
4815 /* Make sure the template headers we got make sense. */
4820 {
4823 }
4824 else
4826 {
4831 {
4835 else
4839 /* Avoid crash in import_export_decl. */
4842 }
4847 /* Can happen in erroneous input. */
4849 else
4851 }
4853 /* Check that the parms are used in the appropriate qualifying scopes
4854 in the declarator. */
4858 {
4864 /* Avoid crash in import_export_decl. */
4867 }
4868 }
4873 /* Push template declarations for global functions and types. Note
4874 that we do not try to push a global template friend declared in a
4875 template class; such a thing may well depend on the template
4876 parameters of the class. */
4879 {
4884 /* Hide template friend classes that haven't been declared yet. */
4886 {
4889 }
4890 }
4893 {
4899 {
4902 /* It is a conversion operator. See if the type converted to
4903 depends on innermost template operands. */
4906 depth))
4908 }
4910 /* Give template template parms a DECL_CONTEXT of the template
4911 for which they are a parameter. */
4914 {
4918 }
4919 }
4921 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
4922 back to its most general template. If TMPL is a specialization,
4923 ARGS may only have the innermost set of arguments. Add the missing
4924 argument levels if necessary. */
4932 else
4933 {
4938 }
4941 }
4943 tree
4945 {
4947 }
4949 /* FN is an inheriting constructor that inherits from the constructor
4950 template INHERITED; turn FN into a constructor template with a matching
4951 template header. */
4953 tree
4955 {
4956 tree inner_parms
4959 tree parms
4970 }
4972 /* Called when a class template TYPE is redeclared with the indicated
4973 template PARMS, e.g.:
4975 template <class T> struct S;
4976 template <class T> struct S {}; */
4978 bool
4980 {
4981 tree tmpl;
4982 tree tmpl_parms;
4986 {
4989 }
4993 /* The type is nested in some template class. Nothing to worry
4994 about here; there are no new template parameters for the nested
4995 type. */
4999 {
5001 tmpl);
5003 }
5009 {
5019 }
5022 {
5023 tree tmpl_parm;
5024 tree parm;
5025 tree tmpl_default;
5026 tree parm_default;
5040 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5041 TEMPLATE_DECL. */
5051 {
5055 }
5058 {
5059 /* We have in [temp.param]:
5061 A template-parameter may not be given default arguments
5062 by two different declarations in the same scope. */
5067 }
5070 /* Update the previous template parameters (which are the ones
5071 that will really count) with the new default value. */
5074 /* Update the new parameters, too; they'll be used as the
5075 parameters for any members. */
5077 }
5080 }
5082 /* Simplify EXPR if it is a non-dependent expression. Returns the
5083 (possibly simplified) expression. */
5085 tree
5087 {
5091 /* If we're in a template, but EXPR isn't value dependent, simplify
5092 it. We're supposed to treat:
5094 template <typename T> void f(T[1 + 1]);
5095 template <typename T> void f(T[2]);
5097 as two declarations of the same function, for example. */
5101 {
5102 HOST_WIDE_INT saved_processing_template_decl;
5108 complain,
5113 }
5115 }
5117 tree
5119 {
5121 }
5123 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5124 template declaration, or a TYPE_DECL for an alias declaration. */
5126 bool
5128 {
5136 }
5138 /* Return TRUE iff is a specialization of an alias template. */
5140 bool
5142 {
5150 }
5152 /* Return the number of innermost template parameters in TMPL. */
5154 static int
5156 {
5159 }
5161 /* Return either TMPL or another template that it is equivalent to under DR
5162 1286: An alias that just changes the name of a template is equivalent to
5163 the other template. */
5165 static tree
5167 {
5170 {
5173 {
5179 {
5180 /* The alias type is equivalent to the pattern of the
5181 underlying template, so strip the alias. */
5184 }
5185 }
5187 }
5189 }
5191 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5192 must be a function or a pointer-to-function type, as specified
5193 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5194 and check that the resulting function has external linkage. */
5196 static tree
5198 {
5201 linkage_kind linkage;
5213 /* [temp.arg.nontype]/1
5215 A template-argument for a non-type, non-template template-parameter
5216 shall be one of:
5217 [...]
5218 -- the address of an object or function with external [C++11: or
5219 internal] linkage. */
5222 {
5226 else
5229 }
5233 {
5238 else
5243 }
5246 }
5248 /* Subroutine of convert_nontype_argument.
5249 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5250 Emit an error otherwise. */
5252 static bool
5254 tsubst_flags_t complain)
5255 {
5262 {
5266 }
5268 }
5270 /* Returns TRUE iff the address of OP is value-dependent.
5272 14.6.2.4 [temp.dep.temp]:
5273 A non-integral non-type template-argument is dependent if its type is
5274 dependent or it has either of the following forms
5275 qualified-id
5276 & qualified-id
5277 and contains a nested-name-specifier which specifies a class-name that
5278 names a dependent type.
5280 We generalize this to just say that the address of a member of a
5281 dependent class is value-dependent; the above doesn't cover the
5282 address of a static data member named with an unqualified-id. */
5284 static bool
5286 {
5287 /* We could use get_inner_reference here, but there's no need;
5288 this is only relevant for template non-type arguments, which
5289 can only be expressed as &id-expression. */
5291 {
5295 }
5298 }
5300 /* The next set of functions are used for providing helpful explanatory
5301 diagnostics for failed overload resolution. Their messages should be
5302 indented by two spaces for consistency with the messages in
5303 call.c */
5305 static int
5307 {
5309 }
5311 static int
5313 {
5318 }
5320 static int
5322 {
5324 }
5326 static int
5328 {
5334 }
5336 static int
5338 {
5342 }
5344 static int
5346 {
5349 " template parameter %qD is not a parameter pack, but "
5353 }
5355 static int
5357 {
5360 " template argument %qE does not match "
5364 }
5366 static int
5368 {
5372 }
5374 static int
5376 {
5382 }
5384 static int
5386 {
5388 {
5393 else
5395 " deduced conflicting values for non-type parameter "
5397 }
5399 }
5401 static int
5403 {
5406 " variable-sized array type %qT is not "
5408 arg);
5410 }
5412 static int
5414 {
5418 arg);
5420 }
5422 static int
5424 {
5431 }
5433 static int
5435 {
5437 }
5439 static int
5441 {
5443 }
5445 static int
5448 {
5454 }
5456 static int
5459 {
5462 {
5470 }
5472 }
5474 static int
5476 {
5479 " template parameters of a template template argument are "
5482 }
5484 static int
5486 {
5492 }
5494 static int
5496 {
5501 }
5503 static int
5505 {
5509 arg);
5511 }
5513 /* Attempt to convert the non-type template parameter EXPR to the
5514 indicated TYPE. If the conversion is successful, return the
5515 converted value. If the conversion is unsuccessful, return
5516 NULL_TREE if we issued an error message, or error_mark_node if we
5517 did not. We issue error messages for out-and-out bad template
5518 parameters, but not simply because the conversion failed, since we
5519 might be just trying to do argument deduction. Both TYPE and EXPR
5520 must be non-dependent.
5522 The conversion follows the special rules described in
5523 [temp.arg.nontype], and it is much more strict than an implicit
5524 conversion.
5526 This function is called twice for each template argument (see
5527 lookup_template_class for a more accurate description of this
5528 problem). This means that we need to handle expressions which
5529 are not valid in a C++ source, but can be created from the
5530 first call (for instance, casts to perform conversions). These
5531 hacks can go away after we fix the double coercion problem. */
5533 static tree
5535 {
5536 tree expr_type;
5538 /* Detect immediately string literals as invalid non-type argument.
5539 This special-case is not needed for correctness (we would easily
5540 catch this later), but only to provide better diagnostic for this
5541 common user mistake. As suggested by DR 100, we do not mention
5542 linkage issues in the diagnostic as this is not the point. */
5543 /* FIXME we're making this OK. */
5545 {
5551 }
5553 /* Add the ADDR_EXPR now for the benefit of
5554 value_dependent_expression_p. */
5557 {
5561 }
5563 /* If we are in a template, EXPR may be non-dependent, but still
5564 have a syntactic, rather than semantic, form. For example, EXPR
5565 might be a SCOPE_REF, rather than the VAR_DECL to which the
5566 SCOPE_REF refers. Preserving the qualifying scope is necessary
5567 so that access checking can be performed when the template is
5568 instantiated -- but here we need the resolved form so that we can
5569 convert the argument. */
5580 else
5583 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
5584 to a non-type argument of "nullptr". */
5588 /* In C++11, integral or enumeration non-type template arguments can be
5589 arbitrary constant expressions. Pointer and pointer to
5590 member arguments can be general constant expressions that evaluate
5591 to a null value, but otherwise still need to be of a specific form. */
5593 {
5595 /* A PTRMEM_CST is already constant, and a valid template
5596 argument for a parameter of pointer to member type, we just want
5597 to leave it in that form rather than lower it to a
5602 {
5607 }
5608 }
5610 /* HACK: Due to double coercion, we can get a
5611 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5612 which is the tree that we built on the first call (see
5613 below when coercing to reference to object or to reference to
5614 function). We just strip everything and get to the arg.
5615 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5616 for examples. */
5618 {
5624 {
5625 /* ??? Maybe we could use convert_from_reference here, but we
5626 would need to relax its constraints because the NOP_EXPR
5627 could actually change the type to something more cv-qualified,
5628 and this is not folded by convert_from_reference. */
5633 && (same_type_ignoring_top_level_qualifiers_p
5636 {
5639 }
5640 }
5641 }
5643 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5644 parameter is a pointer to object, through decay and
5645 qualification conversion. Let's strip everything. */
5647 {
5652 {
5653 /* Skip the ADDR_EXPR only if it is part of the decay for
5654 an array. Otherwise, it is part of the original argument
5655 in the source code. */
5660 }
5661 }
5663 /* [temp.arg.nontype]/5, bullet 1
5665 For a non-type template-parameter of integral or enumeration type,
5666 integral promotions (_conv.prom_) and integral conversions
5667 (_conv.integral_) are applied. */
5669 {
5678 /* Notice that there are constant expressions like '4 % 0' which
5679 do not fold into integer constants. */
5681 {
5683 {
5694 /* else cxx_constant_value complained but gave us
5695 a real constant, so go ahead. */
5697 }
5698 else
5700 }
5702 /* Avoid typedef problems. */
5705 }
5706 /* [temp.arg.nontype]/5, bullet 2
5708 For a non-type template-parameter of type pointer to object,
5709 qualification conversions (_conv.qual_) and the array-to-pointer
5710 conversion (_conv.array_) are applied. */
5712 {
5713 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
5715 A template-argument for a non-type, non-template template-parameter
5716 shall be one of: [...]
5718 -- the name of a non-type template-parameter;
5719 -- the address of an object or function with external linkage, [...]
5720 expressed as "& id-expression" where the & is optional if the name
5721 refers to a function or array, or if the corresponding
5722 template-parameter is a reference.
5724 Here, we do not care about functions, as they are invalid anyway
5725 for a parameter of type pointer-to-object. */
5728 /* Non-type template parameters are OK. */
5729 ;
5734 {
5736 {
5738 "because %qD is a variable, not the address of "
5742 }
5744 {
5749 }
5750 /* Other values, like integer constants, might be valid
5751 non-type arguments of some other type. */
5753 }
5754 else
5755 {
5756 tree decl;
5761 {
5766 }
5768 {
5773 }
5775 {
5780 }
5781 }
5790 }
5791 /* [temp.arg.nontype]/5, bullet 3
5793 For a non-type template-parameter of type reference to object, no
5794 conversions apply. The type referred to by the reference may be more
5795 cv-qualified than the (otherwise identical) type of the
5796 template-argument. The template-parameter is bound directly to the
5797 template-argument, which must be an lvalue. */
5799 {
5801 expr_type))
5805 {
5809 }
5812 {
5816 }
5818 /* [temp.arg.nontype]/1
5820 A template-argument for a non-type, non-template template-parameter
5821 shall be one of: [...]
5823 -- the address of an object or function with external linkage. */
5826 {
5829 {
5831 "because a reference variable does not have a constant "
5834 }
5835 }
5838 {
5843 }
5846 {
5851 }
5854 }
5855 /* [temp.arg.nontype]/5, bullet 4
5857 For a non-type template-parameter of type pointer to function, only
5858 the function-to-pointer conversion (_conv.func_) is applied. If the
5859 template-argument represents a set of overloaded functions (or a
5860 pointer to such), the matching function is selected from the set
5861 (_over.over_). */
5863 {
5864 /* If the argument is a template-id, we might not have enough
5865 context information to decay the pointer. */
5867 {
5871 }
5874 /* Null pointer values are OK in C++11. */
5880 }
5881 /* [temp.arg.nontype]/5, bullet 5
5883 For a non-type template-parameter of type reference to function, no
5884 conversions apply. If the template-argument represents a set of
5885 overloaded functions, the matching function is selected from the set
5886 (_over.over_). */
5888 {
5890 {
5895 }
5902 }
5903 /* [temp.arg.nontype]/5, bullet 6
5905 For a non-type template-parameter of type pointer to member function,
5906 no conversions apply. If the template-argument represents a set of
5907 overloaded member functions, the matching member function is selected
5908 from the set (_over.over_). */
5910 {
5915 /* [temp.arg.nontype] bullet 1 says the pointer to member
5916 expression must be a pointer-to-member constant. */
5920 /* There is no way to disable standard conversions in
5921 resolve_address_of_overloaded_function (called by
5922 instantiate_type). It is possible that the call succeeded by
5923 converting &B::I to &D::I (where B is a base of D), so we need
5924 to reject this conversion here.
5926 Actually, even if there was a way to disable standard conversions,
5927 it would still be better to reject them here so that we can
5928 provide a superior diagnostic. */
5930 {
5934 /* If we are just one standard conversion off, explain. */
5939 }
5940 }
5941 /* [temp.arg.nontype]/5, bullet 7
5943 For a non-type template-parameter of type pointer to data member,
5944 qualification conversions (_conv.qual_) are applied. */
5946 {
5947 /* [temp.arg.nontype] bullet 1 says the pointer to member
5948 expression must be a pointer-to-member constant. */
5955 }
5957 {
5959 {
5963 }
5965 }
5966 /* A template non-type parameter must be one of the above. */
5967 else
5970 /* Sanity check: did we actually convert the argument to the
5971 right type? */
5975 }
5977 /* Subroutine of coerce_template_template_parms, which returns 1 if
5978 PARM_PARM and ARG_PARM match using the rule for the template
5979 parameters of template template parameters. Both PARM and ARG are
5980 template parameters; the rest of the arguments are the same as for
5981 coerce_template_template_parms.
5982 */
5983 static int
5985 tree arg,
5986 tsubst_flags_t complain,
5987 tree in_decl,
5988 tree outer_args)
5989 {
5998 {
6000 /* We encounter instantiations of templates like
6001 template <template <template <class> class> class TT>
6002 class C; */
6003 {
6010 }
6011 /* Fall through. */
6016 /* Argument is a parameter pack but parameter is not. */
6021 /* The tsubst call is used to handle cases such as
6023 template <int> class C {};
6024 template <class T, template <T> class TT> class D {};
6025 D<int, C> d;
6027 i.e. the parameter list of TT depends on earlier parameters. */
6029 && !same_type_p
6036 /* Argument is a parameter pack but parameter is not. */
6043 }
6046 }
6049 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6050 template template parameters. Both PARM_PARMS and ARG_PARMS are
6051 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6052 or PARM_DECL.
6054 Consider the example:
6055 template <class T> class A;
6056 template<template <class U> class TT> class B;
6058 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6059 the parameters to A, and OUTER_ARGS contains A. */
6061 static int
6063 tree arg_parms,
6064 tsubst_flags_t complain,
6065 tree in_decl,
6066 tree outer_args)
6067 {
6078 /* Determine whether we have a parameter pack at the end of the
6079 template template parameter's template parameter list. */
6081 {
6088 {
6102 }
6103 }
6109 /* Check all of the template parameters except the parameter pack at
6110 the end (if any). */
6112 {
6121 outer_args))
6124 }
6127 {
6128 /* Check each of the template parameters in the template
6129 argument against the template parameter pack at the end of
6130 the template template parameter. */
6137 {
6144 outer_args))
6146 }
6147 }
6150 }
6152 /* Verifies that the deduced template arguments (in TARGS) for the
6153 template template parameters (in TPARMS) represent valid bindings,
6154 by comparing the template parameter list of each template argument
6155 to the template parameter list of its corresponding template
6156 template parameter, in accordance with DR150. This
6157 routine can only be called after all template arguments have been
6158 deduced. It will return TRUE if all of the template template
6159 parameter bindings are okay, FALSE otherwise. */
6160 bool
6162 {
6166 /* We're dealing with template parms in this process. */
6172 {
6177 {
6182 {
6183 /* Look inside the argument pack. */
6186 }
6189 {
6193 /* Extract the next argument from the argument
6194 pack. */
6198 /* Look at the pattern of the pack expansion. */
6201 /* Extract the template parameters from the template
6202 argument. */
6208 /* Verify that we can coerce the template template
6209 parameters from the template argument to the template
6210 parameter. This requires an exact match. */
6212 && !coerce_template_template_parms
6214 targ_parms,
6215 tf_none,
6216 tparm,
6217 targs))
6218 {
6221 }
6222 }
6223 }
6224 }
6226 out:
6230 }
6232 /* Since type attributes aren't mangled, we need to strip them from
6233 template type arguments. */
6235 static tree
6237 {
6238 tree mv;
6245 {
6250 }
6252 }
6254 /* Convert the indicated template ARG as necessary to match the
6255 indicated template PARM. Returns the converted ARG, or
6256 error_mark_node if the conversion was unsuccessful. Error and
6257 warning messages are issued under control of COMPLAIN. This
6258 conversion is for the Ith parameter in the parameter list. ARGS is
6259 the full set of template arguments deduced so far. */
6261 static tree
6263 tree arg,
6264 tree args,
6265 tsubst_flags_t complain,
6267 tree in_decl)
6268 {
6269 tree orig_arg;
6270 tree val;
6275 {
6276 /* The template argument was the name of some
6277 member function. That's usually
6278 invalid, but static members are OK. In any
6279 case, grab the underlying fields/functions
6280 and issue an error later if required. */
6283 }
6291 /* When determining whether an argument pack expansion is a template,
6292 look at the pattern. */
6296 /* Deal with an injected-class-name used as a template template arg. */
6298 {
6301 {
6311 }
6312 }
6314 is_tmpl_type =
6330 {
6332 {
6336 }
6339 "to refer to a type member of a template parameter, "
6344 typename_type,
6345 complain);
6348 }
6350 {
6352 {
6354 {
6364 else
6366 }
6367 }
6369 }
6371 {
6373 {
6379 else
6381 }
6383 }
6386 {
6388 {
6392 /* The number of argument required is not known yet.
6393 Just accept it for now. */
6395 else
6396 {
6398 tree argparm;
6400 /* Strip alias templates that are equivalent to another
6401 template. */
6407 args))
6408 {
6411 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6412 TEMPLATE_DECL. */
6414 {
6419 }
6420 }
6421 else
6422 {
6424 {
6430 }
6433 }
6434 }
6435 }
6436 else
6438 /* We only form one instance of each template specialization.
6439 Therefore, if we use a non-canonical variant (i.e., a
6440 typedef), any future messages referring to the type will use
6441 the typedef, which is confusing if those future uses do not
6442 themselves also use the typedef. */
6445 }
6446 else
6447 {
6454 {
6457 else
6458 {
6459 /* Not sure if this is reachable, but it doesn't hurt
6460 to be robust. */
6463 }
6464 }
6467 /* We used to call digest_init here. However, digest_init
6468 will report errors, which we don't want when complain
6469 is zero. More importantly, digest_init will try too
6470 hard to convert things: for example, `0' should not be
6471 converted to pointer type at this point according to
6472 the standard. Accepting this is not merely an
6473 extension, since deciding whether or not these
6474 conversions can occur is part of determining which
6475 function template to call, or whether a given explicit
6476 argument specification is valid. */
6478 else
6487 {
6488 /* Strip typedefs from the SCOPE_REF. */
6491 complain);
6494 }
6495 }
6498 }
6500 /* Coerces the remaining template arguments in INNER_ARGS (from
6501 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6502 Returns the coerced argument pack. PARM_IDX is the position of this
6503 parameter in the template parameter list. ARGS is the original
6504 template argument list. */
6505 static tree
6508 tree args,
6509 tree inner_args,
6511 tree new_args,
6513 tree in_decl,
6514 tsubst_flags_t complain)
6515 {
6518 tree packed_args;
6519 tree argument_pack;
6529 {
6530 /* When the template parameter is a non-type template
6531 parameter pack whose type uses parameter packs, we need
6532 to look at each of the template arguments
6533 separately. Build a vector of the types for these
6534 non-type template parameters in PACKED_TYPES. */
6535 tree expansion
6543 /* Check that we have the right number of arguments. */
6547 {
6548 int needed_parms
6553 }
6555 /* If we aren't able to check the actual arguments now
6556 (because they haven't been expanded yet), we can at least
6557 verify that all of the types used for the non-type
6558 template parameter pack are, in fact, valid for non-type
6559 template parameters. */
6562 {
6565 {
6569 }
6570 }
6571 }
6573 /* Convert the remaining arguments, which will be a part of the
6574 parameter pack "parm". */
6576 {
6581 {
6582 /* When we have a vector of types (corresponding to the
6583 non-type template parameter pack that uses parameter
6584 packs in its type, as mention above), and the
6585 argument is not an expansion (which expands to a
6586 currently unknown number of arguments), clone the
6587 parm and give it the next type in PACKED_TYPES. */
6591 }
6594 {
6597 }
6598 else
6601 in_decl);
6605 }
6610 else
6611 {
6616 }
6619 #ifdef ENABLE_CHECKING
6622 #endif
6624 }
6626 /* Returns the number of pack expansions in the template argument vector
6627 ARGS. */
6629 static int
6631 {
6636 {
6640 }
6642 }
6644 /* Convert all template arguments to their appropriate types, and
6645 return a vector containing the innermost resulting template
6646 arguments. If any error occurs, return error_mark_node. Error and
6647 warning messages are issued under control of COMPLAIN.
6649 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6650 for arguments not specified in ARGS. Otherwise, if
6651 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
6652 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
6653 USE_DEFAULT_ARGS is false, then all arguments must be specified in
6654 ARGS. */
6656 static tree
6658 tree args,
6659 tree in_decl,
6660 tsubst_flags_t complain,
6663 {
6665 tree inner_args;
6666 tree new_args;
6667 tree new_inner_args;
6671 /* When used as a boolean value, indicates whether this is a
6672 variadic template parameter list. Since it's an int, we can also
6673 subtract it from nparms to get the number of non-variadic
6674 parameters. */
6684 /* Determine if there are any parameter packs. */
6686 {
6692 }
6695 /* If there are no parameters that follow a parameter pack, we need to
6696 expand any argument packs so that we can deduce a parameter pack from
6697 some non-packed args followed by an argument pack, as in variadic85.C.
6698 If there are such parameters, we need to leave argument packs intact
6699 so the arguments are assigned properly. This can happen when dealing
6700 with a nested class inside a partial specialization of a class
6701 template, as in variadic92.C, or when deducing a template parameter pack
6702 from a sub-declarator, as in variadic114.C. */
6706 /* Count any pack expansion args. */
6712 && require_all_args
6713 && !variadic_args_p
6714 && (!use_default_args
6717 {
6719 {
6721 {
6725 }
6726 else
6732 }
6735 }
6736 /* We can't pass a pack expansion to a non-pack parameter of an alias
6737 template (DR 1430). */
6739 && variadic_args_p
6741 {
6743 {
6745 {
6751 {
6756 }
6757 }
6759 found:;
6760 }
6762 }
6764 /* We need to evaluate the template arguments, even though this
6765 template-id may be nested within a "sizeof". */
6773 {
6774 tree arg;
6775 tree parm;
6777 /* Get the Ith template parameter. */
6781 {
6784 }
6786 /* Calculate the next argument. */
6789 else
6794 {
6795 /* All remaining arguments will be placed in the
6796 template parameter pack PARM. */
6802 /* Store this argument. */
6804 lost++;
6807 /* We are done with all of the arguments. */
6811 }
6813 {
6815 {
6816 /* We don't know how many args we have yet, just
6817 use the unconverted ones for now. */
6820 }
6821 }
6823 {
6824 /* There must be a default arg in this case. */
6827 /* The position of the first default template argument,
6828 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
6829 Record that. */
6832 }
6833 else
6837 {
6840 }
6842 /* This only occurs if there was an error in the template
6843 parameter list itself (which we would already have
6844 reported) that we are trying to recover from, e.g., a class
6845 template with a parameter list such as
6846 template<typename..., typename>. */
6848 else
6854 lost++;
6856 }
6863 #ifdef ENABLE_CHECKING
6867 #endif
6870 }
6872 /* Like coerce_template_parms. If PARMS represents all template
6873 parameters levels, this function returns a vector of vectors
6874 representing all the resulting argument levels. Note that in this
6875 case, only the innermost arguments are coerced because the
6876 outermost ones are supposed to have been coerced already.
6878 Otherwise, if PARMS represents only (the innermost) vector of
6879 parameters, this function returns a vector containing just the
6880 innermost resulting arguments. */
6882 static tree
6884 tree args,
6885 tree in_decl,
6886 tsubst_flags_t complain,
6889 {
6892 tree coerced_args;
6895 {
6897 tree level;
6903 {
6904 tree l;
6908 require_all_args,
6909 use_default_args);
6910 else
6917 }
6918 }
6919 else
6922 require_all_args,
6923 use_default_args);
6925 }
6927 /* Returns 1 if template args OT and NT are equivalent. */
6929 static int
6931 {
6938 /* For member templates */
6947 {
6964 }
6966 {
6967 /* We get here probably because we are in the middle of substituting
6968 into the pattern of a pack expansion. In that case the
6969 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
6970 interested in. So we want to use the initial pack argument for
6971 the comparison. */
6976 }
6981 else
6983 }
6985 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
6986 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
6987 NEWARG_PTR with the offending arguments if they are non-NULL. */
6989 static int
6992 {
7005 {
7010 {
7016 }
7017 }
7019 }
7021 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
7022 of template arguments. Returns 0 otherwise. */
7024 int
7026 {
7028 }
7030 static void
7032 {
7042 /* We are called both from instantiate_decl, where we've already had a
7043 tinst_level pushed, and instantiate_template, where we haven't.
7044 Compensate. */
7055 else
7064 }
7067 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
7068 ARGLIST. Valid choices for FNS are given in the cp-tree.def
7069 documentation for TEMPLATE_ID_EXPR. */
7071 tree
7073 {
7074 tree type;
7082 {
7085 }
7088 {
7090 unknown_type_node,
7092 arglist);
7094 }
7101 }
7103 /* Within the scope of a template class S<T>, the name S gets bound
7104 (in build_self_reference) to a TYPE_DECL for the class, not a
7105 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
7106 or one of its enclosing classes, and that type is a template,
7107 return the associated TEMPLATE_DECL. Otherwise, the original
7108 DECL is returned.
7110 Also handle the case when DECL is a TREE_LIST of ambiguous
7111 injected-class-names from different bases. */
7113 tree
7115 {
7119 /* DR 176: A lookup that finds an injected-class-name (10.2
7120 [class.member.lookup]) can result in an ambiguity in certain cases
7121 (for example, if it is found in more than one base class). If all of
7122 the injected-class-names that are found refer to specializations of
7123 the same class template, and if the name is followed by a
7124 template-argument-list, the reference refers to the class template
7125 itself and not a specialization thereof, and is not ambiguous. */
7127 {
7130 {
7136 }
7139 else
7141 }
7147 }
7149 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
7150 parameters, find the desired type.
7152 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
7154 IN_DECL, if non-NULL, is the template declaration we are trying to
7155 instantiate.
7157 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
7158 the class we are looking up.
7160 Issue error and warning messages under control of COMPLAIN.
7162 If the template class is really a local class in a template
7163 function, then the FUNCTION_CONTEXT is the function in which it is
7164 being instantiated.
7166 ??? Note that this function is currently called *twice* for each
7167 template-id: the first time from the parser, while creating the
7168 incomplete type (finish_template_type), and the second type during the
7169 real instantiation (instantiate_template_class). This is surely something
7170 that we want to avoid. It also causes some problems with argument
7171 coercion (see convert_nontype_argument for more information on this). */
7173 static tree
7176 {
7178 tree t;
7181 spec_entry elt;
7182 hashval_t hash;
7185 {
7189 else
7190 {
7197 }
7200 }
7202 {
7205 /* If we are declaring a constructor, say A<T>::A<T>, we will get
7206 an implicit typename for the second A. Deal with it. */
7211 {
7214 }
7215 }
7218 {
7221 }
7225 {
7229 }
7231 {
7234 }
7236 /* Issue an error message if we didn't find a template. */
7238 {
7242 }
7245 /* Make sure it's a user visible template, if it was named by
7246 the user. */
7249 {
7251 {
7255 }
7257 }
7261 /* An alias that just changes the name of a template is equivalent to the
7262 other template, so if any of the arguments are pack expansions, strip
7263 the alias to avoid problems with a pack expansion passed to a non-pack
7264 alias template parameter (DR 1430). */
7269 {
7270 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7271 template arguments */
7273 tree parm;
7274 tree arglist2;
7275 tree outer;
7279 /* Consider an example where a template template parameter declared as
7281 template <class T, class U = std::allocator<T> > class TT
7283 The template parameter level of T and U are one level larger than
7284 of TT. To proper process the default argument of U, say when an
7285 instantiation `TT<int>' is seen, we need to build the full
7286 arguments containing {int} as the innermost level. Outer levels,
7287 available when not appearing as default template argument, can be
7288 obtained from the arguments of the enclosing template.
7290 Suppose that TT is later substituted with std::vector. The above
7291 instantiation is `TT<int, std::allocator<T> >' with TT at
7292 level 1, and T at level 2, while the template arguments at level 1
7293 becomes {std::vector} and the inner level 2 is {int}. */
7299 /* This is an argument of the current template, so we haven't set
7300 DECL_CONTEXT yet. */
7307 complain,
7317 }
7318 else
7319 {
7321 tree gen_tmpl;
7322 tree type_decl;
7330 /* An error occurred while building the template TEMPL, and a
7331 diagnostic has most certainly been emitted for that
7332 already. Let's propagate that error. */
7341 {
7342 /* We've been given an incomplete set of template arguments.
7343 For example, given:
7345 template <class T> struct S1 {
7346 template <class U> struct S2 {};
7347 template <class U> struct S2<U*> {};
7348 };
7350 we will be called with an ARGLIST of `U*', but the
7351 TEMPLATE will be `template <class T> template
7352 <class U> struct S1<T>::S2'. We must fill in the missing
7353 arguments. */
7354 arglist
7356 arglist);
7358 }
7360 /* Now we should have enough arguments. */
7363 /* From here on, we're only interested in the most general
7364 template. */
7366 /* Calculate the BOUND_ARGS. These will be the args that are
7367 actually tsubst'd into the definition to create the
7368 instantiation. */
7370 {
7371 /* We have multiple levels of arguments to coerce, at once. */
7381 {
7382 tree a;
7386 complain,
7389 else
7390 /* Outer levels should have already been coerced. */
7393 /* Don't process further if one of the levels fails. */
7395 {
7396 /* Restore the ARGLIST to its full size. */
7399 }
7403 /* We temporarily reduce the length of the ARGLIST so
7404 that coerce_template_parms will see only the arguments
7405 corresponding to the template parameters it is
7406 examining. */
7408 }
7410 /* Restore the ARGLIST to its full size. */
7414 }
7415 else
7416 arglist
7419 gen_tmpl,
7420 complain,
7425 /* We were unable to bind the arguments. */
7428 /* In the scope of a template class, explicit references to the
7429 template class refer to the type of the template, not any
7430 instantiation of it. For example, in:
7432 template <class T> class C { void f(C<T>); }
7434 the `C<T>' is just the same as `C'. Outside of the
7435 class, however, such a reference is an instantiation. */
7439 /* comp_template_args is expensive, check it last. */
7441 arglist))
7444 /* If we already have this specialization, return it. */
7456 /* If the deduced arguments are invalid, then the binding
7457 failed. */
7461 complain))
7468 {
7473 }
7483 /* Create the type. */
7485 {
7486 /* The user referred to a specialization of an alias
7487 template represented by GEN_TMPL.
7489 [temp.alias]/2 says:
7491 When a template-id refers to the specialization of an
7492 alias template, it is equivalent to the associated
7493 type obtained by substitution of its
7494 template-arguments for the template-parameters in the
7495 type-id of the alias template. */
7498 /* Note that the call above (by indirectly calling
7499 register_specialization in tsubst_decl) registers the
7500 TYPE_DECL representing the specialization of the alias
7501 template. So next time someone substitutes ARGLIST for
7502 the template parms into the alias template (GEN_TMPL),
7503 she'll get that TYPE_DECL back. */
7507 }
7509 {
7511 {
7517 }
7518 else
7519 {
7520 /* We don't want to call start_enum for this type, since
7521 the values for the enumeration constants may involve
7522 template parameters. And, no one should be interested
7523 in the enumeration constants for such a type. */
7526 }
7530 }
7532 {
7539 /* A local class. Make sure the decl gets registered properly. */
7544 /* This instantiation is another name for the primary
7545 template type. Set the TYPE_CANONICAL field
7546 appropriately. */
7549 /* Some of the template arguments require structural
7550 equality testing, so this template class requires
7551 structural equality testing. */
7553 }
7554 else
7557 /* If we called start_enum or pushtag above, this information
7558 will already be set up. */
7560 {
7567 }
7568 else
7572 {
7578 {
7581 }
7582 }
7584 /* Let's consider the explicit specialization of a member
7585 of a class template specialization that is implicitely instantiated,
7586 e.g.:
7587 template<class T>
7588 struct S
7589 {
7590 template<class U> struct M {}; //#0
7591 };
7593 template<>
7594 template<>
7595 struct S<int>::M<char> //#1
7596 {
7597 int i;
7598 };
7599 [temp.expl.spec]/4 says this is valid.
7601 In this case, when we write:
7602 S<int>::M<char> m;
7604 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
7605 the one of #0.
7607 When we encounter #1, we want to store the partial instantiation
7608 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
7610 For all cases other than this "explicit specialization of member of a
7611 class template", we just want to store the most general template into
7612 the CLASSTYPE_TI_TEMPLATE of M.
7614 This case of "explicit specialization of member of a class template"
7615 only happens when:
7616 1/ the enclosing class is an instantiation of, and therefore not
7617 the same as, the context of the most general template, and
7618 2/ we aren't looking at the partial instantiation itself, i.e.
7619 the innermost arguments are not the same as the innermost parms of
7620 the most general template.
7622 So it's only when 1/ and 2/ happens that we want to use the partial
7623 instantiation of the member template in lieu of its most general
7624 template. */
7628 /* the enclosing class must be an instantiation... */
7631 {
7632 tree partial_inst_args;
7635 partial_inst_args =
7641 use_partial_inst_tmpl =
7642 /*...and we must not be looking at the partial instantiation
7643 itself. */
7645 partial_inst_args);
7646 }
7649 /* This case is easy; there are no member templates involved. */
7651 else
7652 {
7653 /* This is a full instantiation of a member template. Find
7654 the partial instantiation of which this is an instance. */
7656 /* Temporarily reduce by one the number of levels in the ARGLIST
7657 so as to avoid comparing the last set of arguments. */
7661 /* FOUND is either a proper class type, or an alias
7662 template specialization. In the later case, it's a
7663 TYPE_DECL, resulting from the substituting of arguments
7664 for parameters in the TYPE_DECL of the alias template
7665 done earlier. So be careful while getting the template
7666 of FOUND. */
7670 }
7681 /* Note this use of the partial instantiation so we can check it
7682 later in maybe_process_partial_specialization. */
7689 /* Now that the type has been registered on the instantiations
7690 list, we set up the enumerators. Because the enumeration
7691 constants may involve the enumeration type itself, we make
7692 sure to register the type first, and then create the
7693 constants. That way, doing tsubst_expr for the enumeration
7694 constants won't result in recursive calls here; we'll find
7695 the instantiation and exit above. */
7699 /* If the type makes use of template parameters, the
7700 code that generates debugging information will crash. */
7703 /* Possibly limit visibility based on template args. */
7708 }
7709 }
7711 /* Wrapper for lookup_template_class_1. */
7713 tree
7716 {
7717 tree ret;
7723 }
7724 \f
7725 struct pair_fn_data
7726 {
7727 tree_fn_t fn;
7729 /* True when we should also visit template parameters that occur in
7730 non-deduced contexts. */
7733 };
7735 /* Called from for_each_template_parm via walk_tree. */
7737 static tree
7739 {
7752 {
7756 /* Fall through. */
7779 /* Since we're not going to walk subtrees, we have to do this
7780 explicitly here. */
7784 /* Fall through. */
7787 /* Check the return type. */
7792 /* Check the parameter types. Since default arguments are not
7793 instantiated until they are needed, the TYPE_ARG_TYPES may
7794 contain expressions that involve template parameters. But,
7795 no-one should be looking at them yet. And, once they're
7796 instantiated, they don't contain template parameters, so
7797 there's no point in looking at them then, either. */
7798 {
7799 tree parm;
7806 /* Since we've already handled the TYPE_ARG_TYPES, we don't
7807 want walk_tree walking into them itself. */
7809 }
7827 /* Fall through. */
7843 /* Record template parameters such as `T' inside `TT<T>'. */
7847 /* Fall through. */
7859 /* A template template parameter is encountered. */
7865 /* Already substituted template template parameter */
7888 /* If there's no type, then this thing must be some expression
7889 involving template parameters. */
7911 }
7913 /* We didn't find any template parameters we liked. */
7915 }
7917 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
7918 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
7919 call FN with the parameter and the DATA.
7920 If FN returns nonzero, the iteration is terminated, and
7921 for_each_template_parm returns 1. Otherwise, the iteration
7922 continues. If FN never returns a nonzero value, the value
7923 returned by for_each_template_parm is 0. If FN is NULL, it is
7924 considered to be the function which always returns 1.
7926 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
7927 parameters that occur in non-deduced contexts. When false, only
7928 visits those template parameters that can be deduced. */
7930 static int
7934 {
7938 /* Set up. */
7943 /* Walk the tree. (Conceptually, we would like to walk without
7944 duplicates, but for_each_template_parm_r recursively calls
7945 for_each_template_parm, so we would need to reorganize a fair
7946 bit to use walk_tree_without_duplicates, so we keep our own
7947 visited list.) */
7950 else
7953 for_each_template_parm_r,
7957 /* Clean up. */
7959 {
7962 }
7965 }
7967 /* Returns true if T depends on any template parameter. */
7969 int
7971 {
7998 else
7999 {
8002 }
8007 }
8009 /* Returns true iff current_function_decl is an incompletely instantiated
8010 template. Useful instead of processing_template_decl because the latter
8011 is set to 0 during fold_non_dependent_expr. */
8013 bool
8015 {
8024 }
8026 /* Returns true if T depends on any template parameter with level LEVEL. */
8028 int
8030 {
8033 }
8035 /* Returns TRUE iff INST is an instantiation we don't need to do in an
8036 ill-formed translation unit, i.e. a variable or function that isn't
8037 usable in a constant expression. */
8041 {
8045 }
8047 /* Returns TRUE iff we should refuse to instantiate DECL because it's
8048 neglectable and instantiated from within an erroneous instantiation. */
8050 static bool
8052 {
8063 }
8071 /* We're starting to instantiate D; record the template instantiation context
8072 for diagnostics and to restore it later. */
8074 int
8076 {
8080 {
8086 else
8094 }
8096 /* If the current instantiation caused problems, don't let it instantiate
8097 anything else. Do allow deduction substitution and decls usable in
8098 constant expressions. */
8115 }
8117 /* We're done instantiating this template; return to the instantiation
8118 context. */
8120 void
8122 {
8123 /* Restore the filename and line number stashed away when we started
8124 this instantiation. */
8128 }
8130 /* We're instantiating a deferred template; restore the template
8131 instantiation context in which the instantiation was requested, which
8132 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
8134 static tree
8136 {
8148 }
8150 /* Returns the TINST_LEVEL which gives the original instantiation
8151 context. */
8155 {
8161 }
8163 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
8164 vector of template arguments, as for tsubst.
8166 Returns an appropriate tsubst'd friend declaration. */
8168 static tree
8170 {
8171 tree new_friend;
8176 /* This was a friend declared with an explicit template
8177 argument list, e.g.:
8179 friend void f<>(T);
8181 to indicate that f was a template instantiation, not a new
8182 function declaration. Now, we have to figure out what
8183 instantiation of what template. */
8184 {
8186 tree new_args;
8187 tree tmpl;
8190 /* Friend functions are looked up in the containing namespace scope.
8191 We must enter that scope, to avoid finding member functions of the
8192 current class with same name. */
8207 tsk_none);
8209 }
8213 /* The NEW_FRIEND will look like an instantiation, to the
8214 compiler, but is not an instantiation from the point of view of
8215 the language. For example, we might have had:
8217 template <class T> struct S {
8218 template <class U> friend void f(T, U);
8219 };
8221 Then, in S<int>, template <class U> void f(int, U) is not an
8222 instantiation of anything. */
8228 {
8232 }
8234 /* The mangled name for the NEW_FRIEND is incorrect. The function
8235 is not a template instantiation and should not be mangled like
8236 one. Therefore, we forget the mangling here; we'll recompute it
8237 later if we need it. */
8239 {
8242 }
8245 {
8246 tree old_decl;
8247 tree new_friend_template_info;
8248 tree new_friend_result_template_info;
8249 tree ns;
8252 /* We must save some information from NEW_FRIEND before calling
8253 duplicate decls since that function will free NEW_FRIEND if
8254 possible. */
8256 new_friend_is_defn =
8261 {
8262 /* This declaration is a `primary' template. */
8265 new_friend_result_template_info
8267 }
8268 else
8271 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8275 /* Inside pushdecl_namespace_level, we will push into the
8276 current namespace. However, the friend function should go
8277 into the namespace of the template. */
8287 {
8288 /* This new friend declaration matched an existing
8289 declaration. For example, given:
8291 template <class T> void f(T);
8292 template <class U> class C {
8293 template <class T> friend void f(T) {}
8294 };
8296 the friend declaration actually provides the definition
8297 of `f', once C has been instantiated for some type. So,
8298 old_decl will be the out-of-class template declaration,
8299 while new_friend is the in-class definition.
8301 But, if `f' was called before this point, the
8302 instantiation of `f' will have DECL_TI_ARGS corresponding
8303 to `T' but not to `U', references to which might appear
8304 in the definition of `f'. Previously, the most general
8305 template for an instantiation of `f' was the out-of-class
8306 version; now it is the in-class version. Therefore, we
8307 run through all specialization of `f', adding to their
8308 DECL_TI_ARGS appropriately. In particular, they need a
8309 new set of outer arguments, corresponding to the
8310 arguments for this class instantiation.
8312 The same situation can arise with something like this:
8314 friend void f(int);
8315 template <class T> class C {
8316 friend void f(T) {}
8317 };
8319 when `C<int>' is instantiated. Now, `f(int)' is defined
8320 in the class. */
8323 /* On the other hand, if the in-class declaration does
8324 *not* provide a definition, then we don't want to alter
8325 existing definitions. We can just leave everything
8326 alone. */
8327 ;
8328 else
8329 {
8333 /* Overwrite whatever template info was there before, if
8334 any, with the new template information pertaining to
8335 the declaration. */
8339 {
8340 /* We should have called reregister_specialization in
8341 duplicate_decls. */
8346 /* Instantiate it if the global has already been used. */
8350 }
8351 else
8352 {
8353 tree t;
8355 /* Indicate that the old function template is a partial
8356 instantiation. */
8364 /* Reassign any specializations already in the hash table
8365 to the new more general template, and add the
8366 additional template args. */
8370 {
8372 spec_entry elt;
8384 register_specialization
8387 }
8389 }
8390 }
8392 /* The information from NEW_FRIEND has been merged into OLD_DECL
8393 by duplicate_decls. */
8395 }
8396 }
8397 else
8398 {
8402 /* In the code
8403 template <class T> class C {
8404 template <class U> friend void C1<U>::f (); // case 1
8405 friend void C2<T>::f (); // case 2
8406 };
8407 we only need to make sure CONTEXT is a complete type for
8408 case 2. To distinguish between the two cases, we note that
8409 CONTEXT of case 1 remains dependent type after tsubst while
8410 this isn't true for case 2. */
8420 {
8421 /* Check to see that the declaration is really present, and,
8422 possibly obtain an improved declaration. */
8428 }
8429 }
8432 }
8434 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8435 template arguments, as for tsubst.
8437 Returns an appropriate tsubst'd friend type or error_mark_node on
8438 failure. */
8440 static tree
8442 {
8443 tree friend_type;
8444 tree tmpl;
8445 tree context;
8448 {
8451 }
8456 {
8459 else
8461 }
8463 /* Look for a class template declaration. We look for hidden names
8464 because two friend declarations of the same template are the
8465 same. For example, in:
8467 struct A {
8468 template <typename> friend class F;
8469 };
8470 template <typename> struct B {
8471 template <typename> friend class F;
8472 };
8474 both F templates are the same. */
8478 /* But, if we don't find one, it might be because we're in a
8479 situation like this:
8481 template <class T>
8482 struct S {
8483 template <class U>
8484 friend struct S;
8485 };
8487 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8488 for `S<int>', not the TEMPLATE_DECL. */
8490 {
8493 }
8496 {
8497 /* The friend template has already been declared. Just
8498 check to see that the declarations match, and install any new
8499 default parameters. We must tsubst the default parameters,
8500 of course. We only need the innermost template parameters
8501 because that is all that redeclare_class_template will look
8502 at. */
8505 {
8506 tree parms;
8507 location_t saved_input_location;
8516 }
8519 }
8520 else
8521 {
8522 /* The friend template has not already been declared. In this
8523 case, the instantiation of the template class will cause the
8524 injection of this template into the global scope. */
8529 /* The new TMPL is not an instantiation of anything, so we
8530 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
8531 the new type because that is supposed to be the corresponding
8532 template decl, i.e., TMPL. */
8539 /* Inject this template into the global scope. */
8541 }
8544 {
8547 else
8549 }
8552 }
8554 /* Returns zero if TYPE cannot be completed later due to circularity.
8555 Otherwise returns one. */
8557 static int
8559 {
8569 else
8571 }
8575 /* Apply any attributes which had to be deferred until instantiation
8576 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
8577 ARGS, COMPLAIN, IN_DECL are as tsubst. */
8579 static void
8582 {
8584 tree t;
8589 {
8593 }
8596 {
8600 }
8601 else
8605 {
8610 {
8613 {
8620 {
8627 clauses
8631 else
8633 }
8634 /* If the first attribute argument is an identifier, don't
8635 pass it through tsubst. Attributes like mode, format,
8636 cleanup and several target specific attributes expect it
8637 unmodified. */
8640 {
8641 tree chain
8643 in_decl,
8648 chain);
8649 }
8650 else
8656 }
8657 else
8659 }
8662 }
8663 }
8665 /* Perform (or defer) access check for typedefs that were referenced
8666 from within the template TMPL code.
8667 This is a subroutine of instantiate_decl and instantiate_class_template.
8668 TMPL is the template to consider and TARGS is the list of arguments of
8669 that template. */
8671 static void
8673 {
8674 location_t saved_location;
8685 {
8697 /* Make access check error messages point to the location
8698 of the use of the typedef. */
8702 tf_warning_or_error);
8703 }
8705 }
8707 static tree
8709 {
8711 tree typedecl;
8712 tree pbinfo;
8713 tree base_list;
8715 tree fn_context;
8724 /* Figure out which template is being instantiated. */
8728 /* Determine what specialization of the original template to
8729 instantiate. */
8732 {
8735 }
8737 {
8738 /* This TYPE is actually an instantiation of a partial
8739 specialization. We replace the innermost set of ARGS with
8740 the arguments appropriate for substitution. For example,
8741 given:
8743 template <class T> struct S {};
8744 template <class T> struct S<T*> {};
8746 and supposing that we are instantiating S<int*>, ARGS will
8747 presently be {int*} -- but we need {int}. */
8750 }
8751 else
8752 {
8755 }
8757 /* If the template we're instantiating is incomplete, then clearly
8758 there's nothing we can do. */
8762 /* If we've recursively instantiated too many templates, stop. */
8766 /* Now we're really doing the instantiation. Mark the type as in
8767 the process of being defined. */
8770 /* We may be in the middle of deferred access check. Disable
8771 it now. */
8777 /* Use #pragma pack from the template context. */
8783 /* Set the input location to the most specialized template definition.
8784 This is needed if tsubsting causes an error. */
8796 {
8799 /* Adjust visibility for template arguments. */
8801 }
8807 /* We should never instantiate a nested class before its enclosing
8808 class; we need to look up the nested class by name before we can
8809 instantiate it, and that lookup should instantiate the enclosing
8810 class. */
8816 {
8817 tree pbase_binfo;
8818 tree pushed_scope;
8821 /* We must enter the scope containing the type, as that is where
8822 the accessibility of types named in dependent bases are
8823 looked up from. */
8826 /* Substitute into each of the bases to determine the actual
8827 basetypes. */
8829 {
8830 tree base;
8836 {
8837 expanded_bases =
8844 }
8847 {
8849 /* Extract the already-expanded base class. */
8851 else
8852 /* Substitute to figure out the base class. */
8854 NULL_TREE);
8862 }
8863 }
8865 /* The list is now in reverse order; correct that. */
8870 }
8871 /* Now call xref_basetypes to set up all the base-class
8872 information. */
8880 /* Now that our base classes are set up, enter the scope of the
8881 class, so that name lookups into base classes, etc. will work
8882 correctly. This is precisely analogous to what we do in
8883 begin_class_definition when defining an ordinary non-template
8884 class, except we also need to push the enclosing classes. */
8887 /* Now members are processed in the order of declaration. */
8890 {
8894 {
8896 {
8897 /* Build new CLASSTYPE_NESTED_UTDS. */
8899 tree newtag;
8905 /* If the member is a class template, then -- even after
8906 substitution -- there may be dependent types in the
8907 template argument list for the class. We increment
8908 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
8909 that function will assume that no types are dependent
8910 when outside of a template. */
8920 {
8924 /* Unfortunately, lookup_template_class sets
8925 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
8926 instantiation (i.e., for the type of a member
8927 template class nested within a template class.)
8928 This behavior is required for
8929 maybe_process_partial_specialization to work
8930 correctly, but is not accurate in this case;
8931 the TAG is not an instantiation of anything.
8932 (The corresponding TEMPLATE_DECL is an
8933 instantiation, but the TYPE is not.) */
8936 /* Now, we call pushtag to put this NEWTAG into the scope of
8937 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
8938 pushtag calling push_template_decl. We don't have to do
8939 this for enums because it will already have been done in
8940 tsubst_enum. */
8944 }
8945 }
8947 {
8948 /* Build new TYPE_METHODS. */
8949 tree r;
8958 /* Instantiate members marked with attribute used. */
8964 }
8965 else
8966 {
8967 /* Build new TYPE_FIELDS. */
8969 {
8970 tree condition;
8973 condition =
8983 }
8985 {
8986 tree r;
8990 /* The file and line for this declaration, to
8991 assist in error message reporting. Since we
8992 called push_tinst_level above, we don't need to
8993 restore these. */
9003 {
9004 /* A capture pack became multiple fields. */
9007 }
9010 {
9014 {
9015 /* In [temp.inst]:
9017 [t]he initialization (and any associated
9018 side-effects) of a static data member does
9019 not occur unless the static data member is
9020 itself used in a way that requires the
9021 definition of the static data member to
9022 exist.
9024 Therefore, we do not substitute into the
9025 initialized for the static data member here. */
9026 finish_static_data_member_decl
9032 /* Instantiate members marked with attribute used. */
9035 }
9037 {
9038 /* Determine whether R has a valid type and can be
9039 completed later. If R is invalid, then its type
9040 is replaced by error_mark_node. */
9046 {
9049 }
9050 }
9052 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
9053 such a thing will already have been added to the field
9054 list by tsubst_enum in finish_member_declaration in the
9055 CLASSTYPE_NESTED_UTDS case above. */
9059 {
9062 }
9063 }
9064 }
9065 }
9066 }
9067 else
9068 {
9071 {
9072 /* Build new CLASSTYPE_FRIEND_CLASSES. */
9078 {
9079 /* template <class T> friend class C; */
9082 }
9084 {
9085 /* template <class T> friend class C::D; */
9091 }
9094 {
9095 /* This could be either
9097 friend class T::C;
9099 when dependent_type_p is false or
9101 template <class U> friend class T::C;
9103 otherwise. */
9106 /* Bump processing_template_decl for correct
9107 dependent_type_p calculation. */
9112 }
9115 {
9116 /* friend class C;
9118 where C hasn't been declared yet. Let's lookup name
9119 from namespace scope directly, bypassing any name that
9120 come from dependent base class. */
9123 /* The call to xref_tag_from_type does injection for friend
9124 classes. */
9126 friend_type =
9130 }
9132 /* friend class C<T>; */
9135 /* Otherwise it's
9137 friend class C;
9139 where C is already declared or
9141 friend class C<int>;
9143 We don't have to do anything in these cases. */
9146 /* Trick make_friend_class into realizing that the friend
9147 we're adding is a template, not an ordinary class. It's
9148 important that we use make_friend_class since it will
9149 perform some error-checking and output cross-reference
9150 information. */
9158 }
9159 else
9160 {
9161 /* Build new DECL_FRIENDLIST. */
9162 tree r;
9164 /* The file and line for this declaration, to
9165 assist in error message reporting. Since we
9166 called push_tinst_level above, we don't need to
9167 restore these. */
9171 {
9174 }
9179 {
9182 }
9183 }
9184 }
9185 }
9188 {
9191 {
9196 /* We need to instantiate the capture list from the template
9197 after we've instantiated the closure members, but before we
9198 consider adding the conversion op. Also keep any captures
9199 that may have been added during instantiation of the op(). */
9201 tree tmpl_cap
9210 }
9211 else
9213 }
9215 /* Set the file and line number information to whatever is given for
9216 the class itself. This puts error messages involving generated
9217 implicit functions at a predictable point, and the same point
9218 that would be used for non-template classes. */
9225 /* We don't instantiate default arguments for member functions. 14.7.1:
9227 The implicit instantiation of a class template specialization causes
9228 the implicit instantiation of the declarations, but not of the
9229 definitions or default arguments, of the class member functions,
9230 member classes, static data members and member templates.... */
9232 /* Some typedefs referenced from within the template code need to be access
9233 checked at template instantiation time, i.e now. These types were
9234 added to the template at parsing time. Let's get those and perform
9235 the access checks then. */
9245 /* The vtable for a template class can be emitted in any translation
9246 unit in which the class is instantiated. When there is no key
9247 method, however, finish_struct_1 will already have added TYPE to
9248 the keyed_classes list. */
9253 }
9255 /* Wrapper for instantiate_class_template_1. */
9257 tree
9259 {
9260 tree ret;
9265 }
9267 static tree
9269 {
9270 tree r;
9276 else
9277 {
9284 /* Preserve the raw-reference nature of T. */
9288 }
9290 }
9292 /* Given a function parameter pack TMPL_PARM and some function parameters
9293 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
9294 and set *SPEC_P to point at the next point in the list. */
9296 static tree
9298 {
9299 /* Collect all of the extra "packed" parameters into an
9300 argument pack. */
9301 tree parmvec;
9302 tree parmtypevec;
9313 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
9318 {
9321 }
9323 /* Build the argument packs. */
9330 }
9332 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9333 NONTYPE_ARGUMENT_PACK. */
9335 static tree
9337 {
9339 }
9341 /* Return true iff the Ith element of the argument pack ARG_PACK is a
9342 pack expansion. */
9344 static bool
9346 {
9351 }
9354 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
9356 static tree
9358 {
9365 }
9367 /* This is a subroutine of tsubst_pack_expansion.
9369 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
9370 mechanism to store the (non complete list of) arguments of the
9371 substitution and return a non substituted pack expansion, in order
9372 to wait for when we have enough arguments to really perform the
9373 substitution. */
9375 static bool
9379 {
9380 /* If one pack has an expansion and another pack has a normal
9381 argument or if one pack has an empty argument and an another
9382 one hasn't then tsubst_pack_expansion cannot perform the
9383 substitution and need to fall back on the
9384 PACK_EXPANSION_EXTRA mechanism. */
9392 {
9395 parm_pack;
9397 {
9402 else
9404 }
9408 }
9410 }
9412 /* [temp.variadic]/6 says that:
9414 The instantiation of a pack expansion [...]
9415 produces a list E1,E2, ..., En, where N is the number of elements
9416 in the pack expansion parameters.
9418 This subroutine of tsubst_pack_expansion produces one of these Ei.
9420 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
9421 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
9422 PATTERN, and each TREE_VALUE is its corresponding argument pack.
9423 INDEX is the index 'i' of the element Ei to produce. ARGS,
9424 COMPLAIN, and IN_DECL are the same parameters as for the
9425 tsubst_pack_expansion function.
9427 The function returns the resulting Ei upon successful completion,
9428 or error_mark_node.
9430 Note that this function possibly modifies the ARGS parameter, so
9431 it's the responsibility of the caller to restore it. */
9433 static tree
9435 tree parm_packs,
9437 tree args /* This parm gets
9439 tsubst_flags_t complain,
9440 tree in_decl)
9441 {
9442 tree t;
9445 /* For each parameter pack, change the substitution of the parameter
9446 pack to the ith argument in its argument pack, then expand the
9447 pattern. */
9449 {
9454 ith_elem_is_expansion |=
9457 /* Select the Ith argument from the pack. */
9460 {
9462 {
9466 }
9467 else
9469 }
9470 else
9471 {
9476 {
9478 /* Update the corresponding argument. */
9480 }
9481 else
9482 /* Re-use the ARGUMENT_PACK_SELECT. */
9484 }
9486 }
9488 /* Substitute into the PATTERN with the (possibly altered)
9489 arguments. */
9493 else
9496 /* If the Ith argument pack element is a pack expansion, then
9497 the Ith element resulting from the substituting is going to
9498 be a pack expansion as well. */
9503 }
9505 /* Substitute ARGS into T, which is an pack expansion
9506 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
9507 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
9508 (if only a partial substitution could be performed) or
9509 ERROR_MARK_NODE if there was an error. */
9510 tree
9512 tree in_decl)
9513 {
9514 tree pattern;
9518 tree result;
9526 /* Add in any args remembered from an earlier partial instantiation. */
9531 /* Determine the argument packs that will instantiate the parameter
9532 packs used in the expansion expression. While we're at it,
9533 compute the number of arguments to be expanded and make sure it
9534 is consistent. */
9537 {
9544 {
9548 else
9551 }
9553 {
9556 else
9557 {
9558 /* We can't rely on local_specializations for a parameter
9559 name used later in a function declaration (such as in a
9560 late-specified return type). Even if it exists, it might
9561 have the wrong value for a recursive call. Just make a
9562 dummy decl, since it's only used for its type. */
9565 /* Partial instantiation of the parm_pack, we can't build
9566 up an argument pack yet. */
9568 else
9571 }
9572 }
9575 else
9576 {
9582 }
9589 /* This can only happen if we forget to expand an argument
9590 pack somewhere else. Just return an error, silently. */
9591 {
9595 }
9598 {
9602 /* Don't bother trying to do a partial substitution with
9603 incomplete packs; we'll try again after deduction. */
9610 {
9616 pattern);
9617 else
9620 pattern);
9622 }
9624 /* Keep track of the parameter packs and their corresponding
9625 argument packs. */
9628 }
9629 else
9630 {
9631 /* We can't substitute for this parameter pack. We use a flag as
9632 well as the missing_level counter because function parameter
9633 packs don't have a level. */
9635 }
9636 }
9638 /* We cannot expand this expansion expression, because we don't have
9639 all of the argument packs we need. */
9641 {
9642 /* We got some full packs, but we can't substitute them in until we
9643 have values for all the packs. So remember these until then. */
9648 }
9650 {
9651 /* There were no real arguments, we're just replacing a parameter
9652 pack with another version of itself. Substitute into the
9653 pattern and return a PACK_EXPANSION_*. The caller will need to
9654 deal with that. */
9658 else
9662 }
9667 {
9668 /* We're in a late-specified return type, so create our own local
9669 specializations map; the current map is either NULL or (in the
9670 case of recursive unification) might have bindings that we don't
9671 want to use or alter. */
9674 }
9676 /* For each argument in each argument pack, substitute into the
9677 pattern. */
9680 {
9682 i,
9684 in_decl);
9687 {
9690 }
9691 }
9693 /* Update ARGS to restore the substitution from parameter packs to
9694 their argument packs. */
9696 {
9702 else
9703 {
9711 /* Update the corresponding argument. */
9715 else
9717 }
9718 }
9721 {
9724 }
9727 }
9729 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
9730 TMPL. We do this using DECL_PARM_INDEX, which should work even with
9731 parameter packs; all parms generated from a function parameter pack will
9732 have the same DECL_PARM_INDEX. */
9734 tree
9736 {
9738 tree patparm;
9741 {
9747 }
9748 else
9749 {
9754 }
9757 }
9759 /* Substitute ARGS into the vector or list of template arguments T. */
9761 static tree
9763 {
9775 {
9777 tree new_arg;
9782 {
9783 /* Substitute into an expansion expression. */
9787 /* Add to the expanded length adjustment the number of
9788 expanded arguments. We subtract one from this
9789 measurement, because the argument pack expression
9790 itself is already counted as 1 in
9791 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
9792 the argument pack is empty. */
9794 }
9796 {
9797 /* Substitute into each of the arguments. */
9803 new_arg,
9817 }
9818 }
9819 else
9828 }
9833 /* Make space for the expanded arguments coming from template
9834 argument packs. */
9836 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
9837 arguments for a member template.
9838 In that case each TREE_VEC in ORIG_T represents a level of template
9839 arguments, and ORIG_T won't carry any non defaulted argument count.
9840 It will rather be the nested TREE_VECs that will carry one.
9841 In other words, ORIG_T carries a non defaulted argument count only
9842 if it doesn't contain any nested TREE_VEC. */
9844 {
9848 }
9850 {
9854 {
9857 /* Now expand the template argument pack "in place". */
9860 }
9861 else
9862 {
9864 out++;
9865 }
9866 }
9869 }
9871 /* Return the result of substituting ARGS into the template parameters
9872 given by PARMS. If there are m levels of ARGS and m + n levels of
9873 PARMS, then the result will contain n levels of PARMS. For
9874 example, if PARMS is `template <class T> template <class U>
9875 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
9876 result will be `template <int*, double, class V>'. */
9878 static tree
9880 {
9884 /* When substituting into a template, we must set
9885 PROCESSING_TEMPLATE_DECL as the template parameters may be
9886 dependent if they are based on one-another, and the dependency
9887 predicates are short-circuit outside of templates. */
9894 {
9895 tree new_vec =
9900 {
9901 tree tuple;
9913 }
9919 }
9924 }
9926 /* Return the result of substituting ARGS into one template parameter
9927 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
9928 parameter and which TREE_PURPOSE is the default argument of the
9929 template parameter. */
9931 static tree
9933 {
9954 }
9956 /* Substitute the ARGS into the indicated aggregate (or enumeration)
9957 type T. If T is not an aggregate or enumeration type, it is
9958 handled as if by tsubst. IN_DECL is as for tsubst. If
9959 ENTERING_SCOPE is nonzero, T is the context for a template which
9960 we are presently tsubst'ing. Return the substituted value. */
9962 static tree
9964 tree args,
9965 tsubst_flags_t complain,
9966 tree in_decl,
9968 {
9973 {
9978 /* Else fall through. */
9982 {
9983 tree argvec;
9984 tree context;
9985 tree r;
9989 /* In "sizeof(X<I>)" we need to evaluate "I". */
9995 /* First, determine the context for the type we are looking
9996 up. */
9999 {
10002 /* If context is a nested class inside a class template,
10003 it may still need to be instantiated (c++/33959). */
10005 }
10007 /* Then, figure out what arguments are appropriate for the
10008 type we are trying to find. For example, given:
10010 template <class T> struct S;
10011 template <class T, class U> void f(T, U) { S<U> su; }
10013 and supposing that we are instantiating f<int, double>,
10014 then our ARGS will be {int, double}, but, when looking up
10015 S we only want {double}. */
10020 else
10021 {
10025 }
10031 }
10032 else
10033 /* This is not a template type, so there's nothing to do. */
10038 }
10039 }
10041 /* Substitute into the default argument ARG (a default argument for
10042 FN), which has the indicated TYPE. */
10044 tree
10046 {
10051 /* This can happen in invalid code. */
10055 /* This default argument came from a template. Instantiate the
10056 default argument here, not in tsubst. In the case of
10057 something like:
10059 template <class T>
10060 struct S {
10061 static T t();
10062 void f(T = t());
10063 };
10065 we must be careful to do name lookup in the scope of S<T>,
10066 rather than in the current class. */
10068 /* The "this" pointer is not valid in a default argument. */
10070 {
10075 }
10078 /* The default argument expression may cause implicitly defined
10079 member functions to be synthesized, which will result in garbage
10080 collection. We must treat this situation as if we were within
10081 the body of function so as to avoid collecting live data on the
10082 stack. */
10090 /* Restore the "this" pointer. */
10092 {
10095 }
10102 /* Make sure the default argument is reasonable. */
10108 }
10110 /* Substitute into all the default arguments for FN. */
10112 static void
10114 {
10115 tree arg;
10116 tree tmpl_args;
10120 /* If this function is not yet instantiated, we certainly don't need
10121 its default arguments. */
10124 /* Don't do this again for clones. */
10129 arg;
10135 complain);
10136 }
10138 /* Substitute the ARGS into the T, which is a _DECL. Return the
10139 result of the substitution. Issue error and warning messages under
10140 control of COMPLAIN. */
10142 static tree
10144 {
10145 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
10146 location_t saved_loc;
10151 /* Set the filename and linenumber to improve error-reporting. */
10156 {
10158 {
10159 /* We can get here when processing a member function template,
10160 member class template, or template template parameter. */
10162 tree spec;
10163 tree tmpl_args;
10164 tree full_args;
10167 {
10168 /* Template template parameter is treated here. */
10172 /* If we get a real template back, return it. This can happen in
10173 the context of most_specialized_class. */
10185 complain);
10188 }
10190 /* We might already have an instance of this template.
10191 The ARGS are for the surrounding class type, so the
10192 full args contain the tsubst'd args for the context,
10193 plus the innermost args from the template decl. */
10197 /* Because this is a template, the arguments will still be
10198 dependent, even after substitution. If
10199 PROCESSING_TEMPLATE_DECL is not set, the dependency
10200 predicates will short-circuit. */
10208 /* If this is a default template template argument,
10209 tsubst might not have changed anything. */
10216 {
10219 }
10221 /* Make a new template decl. It will be similar to the
10222 original, but will record the current template arguments.
10223 We also create a new function declaration, which is just
10224 like the old one, but points to this new template, rather
10225 than the old one. */
10234 {
10235 tree new_type;
10243 /* For a partial specialization, we need to keep pointing to
10244 the primary template. */
10250 }
10251 else
10252 {
10253 tree new_decl;
10265 }
10271 /* The template parameters for this new template are all the
10272 template parameters for the old template, except the
10273 outermost level of parameters. */
10276 complain);
10282 /* Record this non-type partial instantiation. */
10286 }
10290 {
10291 tree ctx;
10294 tree gen_tmpl;
10295 tree type;
10300 /* Nobody should be tsubst'ing into non-template functions. */
10304 {
10305 tree spec;
10308 /* If T is not dependent, just return it. We have to
10309 increment PROCESSING_TEMPLATE_DECL because
10310 value_dependent_expression_p assumes that nothing is
10311 dependent when PROCESSING_TEMPLATE_DECL is zero. */
10318 /* Calculate the most general template of which R is a
10319 specialization, and the complete set of arguments used to
10320 specialize R. */
10323 (DECL_TEMPLATE_RESULT
10329 /* Check to see if we already have this specialization. */
10334 {
10337 }
10339 /* We can see more levels of arguments than parameters if
10340 there was a specialization of a member template, like
10341 this:
10343 template <class T> struct S { template <class U> void f(); }
10344 template <> template <class U> void S<int>::f(U);
10346 Here, we'll be substituting into the specialization,
10347 because that's where we can find the code we actually
10348 want to generate, but we'll have enough arguments for
10349 the most general template.
10351 We also deal with the peculiar case:
10353 template <class T> struct S {
10354 template <class U> friend void f();
10355 };
10356 template <class U> void f() {}
10357 template S<int>;
10358 template void f<double>();
10360 Here, the ARGS for the instantiation of will be {int,
10361 double}. But, we only need as many ARGS as there are
10362 levels of template parameters in CODE_PATTERN. We are
10363 careful not to get fooled into reducing the ARGS in
10364 situations like:
10366 template <class T> struct S { template <class U> void f(U); }
10367 template <class T> template <> void S<T>::f(int) {}
10369 which we can spot because the pattern will be a
10370 specialization in this case. */
10372 parms_depth =
10377 }
10378 else
10379 {
10380 /* This special case arises when we have something like this:
10382 template <class T> struct S {
10383 friend void f<int>(int, double);
10384 };
10386 Here, the DECL_TI_TEMPLATE for the friend declaration
10387 will be an IDENTIFIER_NODE. We are being called from
10388 tsubst_friend_function, and we want only to create a
10389 new decl (R) with appropriate types so that we can call
10390 determine_specialization. */
10392 }
10395 {
10398 else
10402 }
10403 else
10404 {
10407 }
10412 /* If we hit excessive deduction depth, the type is bogus even if
10413 it isn't error_mark_node, so don't build a decl. */
10417 /* We do NOT check for matching decls pushed separately at this
10418 point, as they may not represent instantiations of this
10419 template, and in any case are considered separate under the
10420 discrete model. */
10424 /* Clear out the mangled name and RTL for the instantiation. */
10427 /* Leave DECL_INITIAL set on deleted instantiations. */
10432 /* OpenMP UDRs have the only argument a reference to the declared
10433 type. We want to diagnose if the declared type is a reference,
10434 which is invalid, but as references to references are usually
10435 quietly merged, diagnose it here. */
10437 {
10438 tree argtype
10443 "reference type %qT in "
10447 argtype);
10448 }
10451 /* Type-conversion operator. Reconstruct the name, in
10452 case it's the name of one of the template's parameters. */
10462 /* If this is an instantiation of a function with internal
10463 linkage, we already know what object file linkage will be
10464 assigned to the instantiation. */
10473 /* We'll re-clone as appropriate in instantiate_template. */
10476 /* If we aren't complaining now, return on error before we register
10477 the specialization so that we'll complain eventually. */
10483 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
10484 this in the special friend case mentioned above where
10485 GEN_TMPL is NULL. */
10487 {
10492 tree new_r
10495 /* We instantiated this while substituting into
10496 the type earlier (template/friend54.C). */
10499 /* We're not supposed to instantiate default arguments
10500 until they are called, for a template. But, for a
10501 declaration like:
10503 template <class T> void f ()
10504 { extern void g(int i = T()); }
10506 we should do the substitution when the template is
10507 instantiated. We handle the member function case in
10508 instantiate_class_template since the default arguments
10509 might refer to other members of the class. */
10514 }
10515 else
10518 /* Copy the list of befriending classes. */
10522 {
10526 in_decl);
10527 }
10530 {
10536 /* If this is an instantiation of a member template, clone it.
10537 If it isn't, that'll be handled by
10538 clone_constructors_and_destructors. */
10541 }
10552 /* Possibly limit visibility based on template args. */
10555 {
10559 }
10567 }
10571 {
10579 {
10580 /* If there is a local specialization that isn't a
10581 parameter pack, it means that we're doing a "simple"
10582 substitution from inside tsubst_pack_expansion. Just
10583 return the local specialization (which will be a single
10584 parm). */
10591 /* Expand the TYPE_PACK_EXPANSION that provides the types for
10592 the parameters in this function parameter pack. */
10596 {
10599 /* Zero-length parameter packs are boring. Just substitute
10600 into the chain. */
10604 }
10605 else
10606 {
10607 /* All we did was update the type. Make a note of that. */
10610 }
10611 }
10613 /* Loop through all of the parameters we'll build. When T is
10614 a function parameter pack, LEN is the number of expanded
10615 types in EXPANDED_TYPES; otherwise, LEN is 1. */
10618 {
10625 /* We're on the Ith parameter of the function parameter
10626 pack. */
10627 {
10628 /* Get the Ith type. */
10631 /* Rename the parameter to include the index. */
10634 }
10636 /* We're dealing with a normal parameter. */
10644 {
10647 else
10650 }
10660 /* Keep track of the first new parameter we
10661 generate. That's what will be returned to the
10662 caller. */
10666 /* Build a proper chain of parameters when substituting
10667 into a function parameter pack. */
10670 }
10672 /* If cp_unevaluated_operand is set, we're just looking for a
10673 single dummy parameter, so don't keep going. */
10678 /* FIRST_R contains the start of the chain we've built. */
10680 }
10684 {
10691 {
10692 /* This field is a lambda capture pack. Return a TREE_VEC of
10693 the expanded fields to instantiate_class_template_1 and
10694 store them in the specializations hash table as a
10695 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
10699 {
10702 }
10703 else
10704 {
10705 /* All we did was update the type. Make a note of that. */
10708 }
10709 }
10712 {
10715 {
10719 }
10729 /* For bit-fields, DECL_INITIAL gives the number of bits. For
10730 non-bit-fields DECL_INITIAL is a non-static data member
10731 initializer, which gets deferred instantiation. */
10737 {
10738 /* Set up DECL_TEMPLATE_INFO so that we can get at the
10739 NSDMI in perform_member_init. Still set DECL_INITIAL
10740 so that we know there is one. */
10745 }
10746 /* We don't have to set DECL_CONTEXT here; it is set by
10747 finish_member_declaration. */
10755 }
10758 {
10766 }
10767 }
10771 /* We reach here only for member using decls. We also need to check
10772 uses_template_parms because DECL_DEPENDENT_P is not set for a
10773 using-declaration that designates a member of the current
10774 instantiation (c++/53549). */
10777 {
10784 else
10785 {
10788 }
10789 }
10790 else
10791 {
10794 }
10799 {
10802 tree spec;
10804 tree ctx;
10810 {
10811 /* If this is the canonical decl, we don't have to
10812 mess with instantiations, and often we can't (for
10813 typename, template type parms and such). Note that
10814 TYPE_NAME is not correct for the above test if
10815 we've copied the type for a typedef. */
10821 }
10823 /* Check to see if we already have the specialization we
10824 need. */
10827 {
10828 /* T is a static data member or namespace-scope entity.
10829 We have to substitute into namespace-scope variables
10830 (even though such entities are never templates) because
10831 of cases like:
10833 template <class T> void f() { extern T t; }
10835 where the entity referenced is not known until
10836 instantiation time. */
10840 {
10842 complain,
10844 /* If CTX is unchanged, then T is in fact the
10845 specialization we want. That situation occurs when
10846 referencing a static data member within in its own
10847 class. We can use pointer equality, rather than
10848 same_type_p, because DECL_CONTEXT is always
10849 canonical... */
10852 /* ... unless T is a member template; in which
10853 case our caller can be willing to create a
10854 specialization of that template represented
10855 by T. */
10859 }
10862 {
10870 }
10871 }
10872 else
10873 {
10874 /* A local variable. */
10876 /* Subsequent calls to pushdecl will fill this in. */
10879 }
10880 /* If we already have the specialization we need, there is
10881 nothing more to do. */
10883 {
10886 }
10888 /* Create a new node for the specialization we need. */
10891 {
10894 else
10901 }
10903 {
10904 /* Even if the original location is out of scope, the
10905 newly substituted one is not. */
10912 {
10913 /* It may seem that this case cannot occur, since:
10915 typedef void f();
10916 void g() { f x; }
10918 declares a function, not a variable. However:
10920 typedef void f();
10921 template <typename T> void g() { T t; }
10922 template void g<f>();
10924 is an attempt to declare a variable with function
10925 type. */
10927 /* R is not yet sufficiently initialized, so we
10928 just use its name. */
10931 }
10933 /* Wait until cp_finish_decl to set this again, to handle
10934 circular dependency (template/instantiate6.C). */
10939 {
10944 {
10947 }
10949 }
10950 }
10956 /* Clear out the mangled name and RTL for the instantiation. */
10960 /* The initializer must not be expanded until it is required;
10961 see [temp.inst]. */
10967 {
10968 /* Possibly limit visibility based on template args. */
10971 {
10975 }
10977 }
10980 {
10981 /* A static data member declaration is always marked
10982 external when it is declared in-class, even if an
10983 initializer is present. We mimic the non-template
10984 processing here. */
10990 }
10993 else
11002 /* Preserve a typedef that names a type. */
11004 {
11007 }
11010 }
11015 }
11016 #undef RETURN
11018 out:
11019 /* Restore the file and line information. */
11023 }
11025 /* Substitute into the ARG_TYPES of a function type.
11026 If END is a TREE_CHAIN, leave it and any following types
11027 un-substituted. */
11029 static tree
11031 tree args,
11032 tree end,
11033 tsubst_flags_t complain,
11034 tree in_decl)
11035 {
11036 tree remaining_arg_types;
11040 tree default_arg;
11051 {
11052 /* For a pack expansion, perform substitution on the
11053 entire expression. Later on, we'll handle the arguments
11054 one-by-one. */
11059 /* So that we'll spin through the parameters, one by one. */
11061 else
11062 {
11063 /* We only partially substituted into the parameter
11064 pack. Our type is TYPE_PACK_EXPANSION. */
11067 }
11068 }
11081 {
11083 {
11087 }
11089 }
11090 /* DR 657. */
11094 /* Do array-to-pointer, function-to-pointer conversion, and ignore
11095 top-level qualifiers as required. */
11098 /* We do not substitute into default arguments here. The standard
11099 mandates that they be instantiated only when needed, which is
11100 done in build_over_call. */
11104 {
11105 /* We've instantiated a template before its default arguments
11106 have been parsed. This can happen for a nested template
11107 class, and is not an error unless we require the default
11108 argument in a call of this function. */
11109 remaining_arg_types =
11112 }
11113 else
11114 remaining_arg_types =
11116 }
11119 }
11121 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
11122 *not* handle the exception-specification for FNTYPE, because the
11123 initial substitution of explicitly provided template parameters
11124 during argument deduction forbids substitution into the
11125 exception-specification:
11127 [temp.deduct]
11129 All references in the function type of the function template to the
11130 corresponding template parameters are replaced by the specified tem-
11131 plate argument values. If a substitution in a template parameter or
11132 in the function type of the function template results in an invalid
11133 type, type deduction fails. [Note: The equivalent substitution in
11134 exception specifications is done only when the function is instanti-
11135 ated, at which point a program is ill-formed if the substitution
11136 results in an invalid type.] */
11138 static tree
11140 tree args,
11141 tsubst_flags_t complain,
11142 tree in_decl)
11143 {
11144 tree return_type;
11145 tree arg_types;
11146 tree fntype;
11148 /* The TYPE_CONTEXT is not used for function/method types. */
11151 /* Substitute the return type. */
11155 /* DR 486 clarifies that creation of a function type with an
11156 invalid return type is a deduction failure. */
11159 {
11161 {
11164 else
11166 }
11168 }
11169 /* And DR 657. */
11173 /* Substitute the argument types. */
11179 /* Construct a new type node and return it. */
11181 {
11186 }
11187 else
11188 {
11191 {
11192 /* [temp.deduct]
11194 Type deduction may fail for any of the following
11195 reasons:
11197 -- Attempting to create "pointer to member of T" when T
11198 is not a class type. */
11201 r);
11203 }
11208 }
11212 }
11214 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
11215 ARGS into that specification, and return the substituted
11216 specification. If there is no specification, return NULL_TREE. */
11218 static tree
11220 tree args,
11221 tsubst_flags_t complain,
11222 tree in_decl,
11224 {
11225 tree specs;
11226 tree new_specs;
11231 {
11232 /* A noexcept-specifier. */
11237 {
11238 /* Defer instantiation of noexcept-specifiers to avoid
11239 excessive instantiations (c++/49107). */
11242 {
11243 /* We already partially instantiated this member template,
11244 so combine the new args with the old. */
11249 }
11250 else
11251 {
11254 }
11255 }
11256 else
11257 new_specs = tsubst_copy_and_build
11261 }
11263 {
11266 else
11268 {
11269 tree spec;
11274 {
11275 /* Expand the pack expansion type. */
11278 in_decl);
11284 else
11285 {
11286 /* We're substituting into a member template, so
11287 we got a TYPE_PACK_EXPANSION back. Add that
11288 expansion and move on. */
11292 expanded_specs,
11293 complain);
11296 }
11297 }
11300 {
11303 else
11308 complain);
11309 }
11312 }
11313 }
11315 }
11317 /* Take the tree structure T and replace template parameters used
11318 therein with the argument vector ARGS. IN_DECL is an associated
11319 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
11320 Issue error and warning messages under control of COMPLAIN. Note
11321 that we must be relatively non-tolerant of extensions here, in
11322 order to preserve conformance; if we allow substitutions that
11323 should not be allowed, we may allow argument deductions that should
11324 not succeed, and therefore report ambiguous overload situations
11325 where there are none. In theory, we could allow the substitution,
11326 but indicate that it should have failed, and allow our caller to
11327 make sure that the right thing happens, but we don't try to do this
11328 yet.
11330 This function is used for dealing with types, decls and the like;
11331 for expressions, use tsubst_expr or tsubst_copy. */
11333 tree
11335 {
11358 else
11363 /* Reuse typedefs. We need to do this to handle dependent attributes,
11364 such as attribute aligned. */
11367 {
11371 {
11372 /* DECL represents an alias template and we want to
11373 instantiate it. */
11377 }
11381 {
11385 }
11390 else
11391 /* The typedef is from a non-template context. */
11395 {
11397 r = cp_build_qualified_type_real
11401 }
11402 else
11403 {
11404 /* We don't have an instantiation yet, so drop the typedef. */
11409 }
11410 }
11423 {
11449 {
11455 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
11456 needed. */
11462 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
11463 with TREE_SIDE_EFFECTS that indicates this is not an integral
11464 constant expression. */
11467 {
11470 }
11473 }
11479 {
11492 {
11496 {
11497 /* See through ARGUMENT_PACK_SELECT arguments. */
11499 /* If the selected argument is an expansion E, that most
11500 likely means we were called from
11501 gen_elem_of_pack_expansion_instantiation during the
11502 substituting of pack an argument pack (which Ith
11503 element is a pack expansion, where I is
11504 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
11505 In this case, the Ith element resulting from this
11506 substituting is going to be a pack expansion, which
11507 pattern is the pattern of E. Let's return the
11508 pattern of E, and
11509 gen_elem_of_pack_expansion_instantiation will
11510 build the resulting pack expansion from it. */
11513 }
11514 }
11519 {
11521 /* If ARG is an argument pack, we don't actually want to
11522 perform a substitution here, because substitutions
11523 for argument packs are only done
11524 element-by-element. We can get to this point when
11525 substituting the type of a non-type template
11526 parameter pack, when that type actually contains
11527 template parameter packs from an outer template, e.g.,
11529 template<typename... Types> struct A {
11530 template<Types... Values> struct B { };
11531 }; */
11535 {
11541 return cp_build_qualified_type_real
11543 }
11545 {
11546 /* We are processing a type constructed from a
11547 template template parameter. */
11558 /* Consider this code:
11560 template <template <class> class Template>
11561 struct Internal {
11562 template <class Arg> using Bind = Template<Arg>;
11563 };
11565 template <template <class> class Template, class Arg>
11566 using Instantiate = Template<Arg>; //#0
11568 template <template <class> class Template,
11569 class Argument>
11570 using Bind =
11571 Instantiate<Internal<Template>::template Bind,
11572 Argument>; //#1
11574 When #1 is parsed, the
11575 BOUND_TEMPLATE_TEMPLATE_PARM representing the
11576 parameter `Template' in #0 matches the
11577 UNBOUND_CLASS_TEMPLATE representing the argument
11578 `Internal<Template>::template Bind'; We then want
11579 to assemble the type `Bind<Argument>' that can't
11580 be fully created right now, because
11581 `Internal<Template>' not being complete, the Bind
11582 template cannot be looked up in that context. So
11583 we need to "store" `Bind<Argument>' for later
11584 when the context of Bind becomes complete. Let's
11585 store that in a TYPENAME_TYPE. */
11589 argvec),
11590 typename_type,
11591 complain);
11593 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
11594 are resolving nested-types in the signature of a
11595 member function templates. Otherwise ARG is a
11596 TEMPLATE_DECL and is the real template to be
11597 instantiated. */
11605 complain);
11606 return cp_build_qualified_type_real
11608 }
11609 else
11610 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
11612 }
11615 /* This can happen during the attempted tsubst'ing in
11616 unify. This means that we don't yet have any information
11617 about the template parameter in question. */
11620 /* Early in template argument deduction substitution, we don't
11621 want to reduce the level of 'auto', or it will be confused
11622 with a normal template parm in subsequent deduction. */
11626 /* If we get here, we must have been looking at a parm for a
11627 more deeply nested template. Make a new version of this
11628 template parameter, but with a lower level. */
11630 {
11635 {
11637 r = cp_build_qualified_type_real
11641 }
11642 else
11643 {
11654 /* We have reduced the level of the template
11655 template parameter, but not the levels of its
11656 template parameters, so canonical_type_parameter
11657 will not be able to find the canonical template
11658 template parameter for this level. Thus, we
11659 require structural equality checking to compare
11660 TEMPLATE_TEMPLATE_PARMs. */
11664 else
11668 {
11676 }
11677 }
11686 }
11689 }
11692 {
11700 {
11704 }
11707 {
11711 }
11714 {
11718 }
11724 }
11727 /* We should never be tsubsting a binfo. */
11731 /* A vector of template arguments. */
11737 {
11741 /* [temp.deduct]
11743 Type deduction may fail for any of the following
11744 reasons:
11746 -- Attempting to create a pointer to reference type.
11747 -- Attempting to create a reference to a reference type or
11748 a reference to void.
11750 Core issue 106 says that creating a reference to a reference
11751 during instantiation is no longer a cause for failure. We
11752 only enforce this check in strict C++98 mode. */
11756 {
11759 /* We keep track of the last time we issued this error
11760 message to avoid spewing a ton of messages during a
11761 single bad template instantiation. */
11764 {
11769 else
11772 }
11775 }
11779 {
11781 {
11784 type);
11785 else
11787 type);
11788 }
11790 }
11792 {
11796 }
11798 /* In C++0x, during template argument substitution, when there is an
11799 attempt to create a reference to a reference type, reference
11800 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
11802 "If a template-argument for a template-parameter T names a type
11803 that is a reference to a type A, an attempt to create the type
11804 'lvalue reference to cv T' creates the type 'lvalue reference to
11805 A,' while an attempt to create the type type rvalue reference to
11806 cv T' creates the type T"
11807 */
11808 r = cp_build_reference_type
11811 else
11818 {
11820 pedwarn
11822 code == REFERENCE_TYPE
11825 else
11827 }
11830 /* Will this ever be needed for TYPE_..._TO values? */
11834 }
11836 {
11839 {
11840 /* [temp.deduct]
11842 Type deduction may fail for any of the following
11843 reasons:
11845 -- Attempting to create "pointer to member of T" when T
11846 is not a class type. */
11850 }
11852 {
11856 }
11858 {
11862 }
11865 {
11866 /* The type of the implicit object parameter gets its
11867 cv-qualifiers from the FUNCTION_TYPE. */
11868 tree memptr;
11869 tree method_type
11874 complain);
11875 }
11876 else
11879 complain);
11880 }
11883 {
11884 tree fntype;
11885 tree specs;
11890 /* Substitute the exception specification. */
11898 }
11900 {
11905 /* As an optimization, we avoid regenerating the array type if
11906 it will obviously be the same as T. */
11910 /* These checks should match the ones in grokdeclarator.
11912 [temp.deduct]
11914 The deduction may fail for any of the following reasons:
11916 -- Attempting to create an array with an element type that
11917 is void, a function type, or a reference type, or [DR337]
11918 an abstract class type. */
11922 {
11926 }
11934 {
11937 }
11940 }
11943 {
11953 {
11957 }
11959 {
11960 /* Normally, make_typename_type does not require that the CTX
11961 have complete type in order to allow things like:
11963 template <class T> struct S { typename S<T>::X Y; };
11965 But, such constructs have already been resolved by this
11966 point, so here CTX really should have complete type, unless
11967 it's a partial instantiation. */
11970 {
11974 }
11975 }
11982 {
11985 }
11988 {
11990 {
11994 else
11996 }
11998 {
12002 else
12004 }
12005 }
12007 return cp_build_qualified_type_real
12009 }
12012 {
12024 }
12027 {
12028 tree type;
12044 complain);
12045 }
12048 {
12049 tree type;
12067 else
12068 {
12072 /* In a template ~id could be either a complement expression
12073 or an unqualified-id naming a destructor; if instantiating
12074 it produces an expression, it's not an id-expression or
12075 member access. */
12078 }
12082 complain);
12083 }
12086 {
12090 }
12094 {
12096 tree packed_out =
12098 args,
12099 complain,
12100 in_decl);
12103 /* For template nontype argument packs, also substitute into
12104 the type. */
12109 }
12124 /* We should use one of the expression tsubsts for these codes. */
12130 }
12131 }
12133 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
12134 type of the expression on the left-hand side of the "." or "->"
12135 operator. */
12137 static tree
12140 {
12141 tree name;
12142 tree qualifying_scope;
12143 tree fns;
12144 tree optype;
12149 /* A baselink indicates a function from a base class. Both the
12150 BASELINK_ACCESS_BINFO and the base class referenced may
12151 indicate bases of the template class, rather than the
12152 instantiated class. In addition, lookups that were not
12153 ambiguous before may be ambiguous now. Therefore, we perform
12154 the lookup again. */
12161 {
12168 }
12176 /* If lookup found a single function, mark it as used at this
12177 point. (If it lookup found multiple functions the one selected
12178 later by overload resolution will be marked as used at that
12179 point.) */
12185 /* Add back the template arguments, if present. */
12190 template_args);
12191 /* Update the conversion operator type. */
12199 qualifying_scope,
12200 object_type);
12202 }
12204 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
12205 true if the qualified-id will be a postfix-expression in-and-of
12206 itself; false if more of the postfix-expression follows the
12207 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
12208 of "&". */
12210 static tree
12214 {
12215 tree expr;
12216 tree scope;
12217 tree name;
12219 tree template_args;
12224 /* Figure out what name to look up. */
12227 {
12235 }
12236 else
12237 {
12240 }
12242 /* Substitute into the qualifying scope. When there are no ARGS, we
12243 are just trying to simplify a non-dependent expression. In that
12244 case the qualifying scope may be dependent, and, in any case,
12245 substituting will not help. */
12248 {
12251 }
12252 else
12256 {
12261 }
12264 {
12266 {
12267 /* A BIT_NOT_EXPR is used to represent a destructor. */
12269 {
12273 }
12274 else
12277 }
12278 else
12282 {
12284 {
12288 }
12290 }
12291 }
12294 {
12296 scope);
12297 /* Remember that there was a reference to this entity. */
12299 }
12302 {
12308 }
12317 {
12318 expr = (adjust_result_of_qualified_name_lookup
12320 expr = (finish_qualified_id_expr
12324 }
12326 /* Expressions do not generally have reference type. */
12328 /* However, if we're about to form a pointer-to-member, we just
12329 want the referenced member referenced. */
12334 }
12336 /* Like tsubst, but deals with expressions. This function just replaces
12337 template parms; to finish processing the resultant expression, use
12338 tsubst_copy_and_build or tsubst_expr. */
12340 static tree
12342 {
12344 tree r;
12352 {
12357 {
12358 /* We get here for a use of 'this' in an NSDMI. */
12364 /* This can happen for a parameter name used later in a function
12365 declaration (such as in a late-specified return type). Just
12366 make a dummy decl, since it's only used for its type. */
12369 /* Give it the template pattern as its context; its true context
12370 hasn't been instantiated yet and this is good enough for
12371 mangling. */
12373 }
12381 {
12382 tree enum_type;
12383 tree v;
12387 /* There is no need to substitute into namespace-scope
12388 enumerators. */
12391 /* If ARGS is NULL, then T is known to be non-dependent. */
12395 /* Unfortunately, we cannot just call lookup_name here.
12396 Consider:
12398 template <int I> int f() {
12399 enum E { a = I };
12400 struct S { void g() { E e = a; } };
12401 };
12403 When we instantiate f<7>::S::g(), say, lookup_name is not
12404 clever enough to find f<7>::a. */
12405 enum_type
12415 /* We didn't find the name. That should never happen; if
12416 name-lookup found it during preliminary parsing, we
12417 should find it again here during instantiation. */
12419 }
12424 {
12425 /* Check for a local specialization set up by
12426 tsubst_pack_expansion. */
12429 {
12433 }
12435 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
12436 tsubst_decl put in the hash table. */
12438 }
12441 {
12442 tree ctx;
12447 {
12450 {
12454 }
12456 }
12457 }
12466 {
12469 {
12471 {
12472 /* Just use name lookup to find a member alias for an
12473 anonymous union, but then add it to the hash table. */
12477 }
12478 else
12479 {
12482 }
12483 }
12484 }
12485 else
12494 /* An OVERLOAD will always be a non-dependent overload set; an
12495 overload set from function scope will just be represented with an
12496 IDENTIFIER_NODE, and from class scope with a BASELINK. */
12512 {
12513 /* Template template argument like the following example need
12514 special treatment:
12516 template <template <class> class TT> struct C {};
12517 template <class T> struct D {
12518 template <class U> struct E {};
12519 C<E> c; // #1
12520 };
12521 D<int> d; // #2
12523 We are processing the template argument `E' in #1 for
12524 the template instantiation #2. Originally, `E' is a
12525 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
12526 have to substitute this with one having context `D<int>'. */
12530 }
12531 else
12532 /* Ordinary template template argument. */
12543 return build1
12549 {
12559 /* We only want to compute the number of arguments. */
12573 {
12580 else
12583 }
12584 else
12586 }
12588 {
12596 }
12597 /* Fall through */
12613 return build1
12618 {
12619 tree object;
12620 tree name;
12625 {
12629 }
12632 {
12642 }
12647 in_decl);
12648 else
12651 }
12689 return build_nt
12702 return build_nt
12709 {
12717 }
12723 {
12724 r = build_nt
12730 }
12733 {
12734 r = build_nt
12740 }
12743 {
12744 r = build_nt
12750 }
12753 {
12754 /* Substituted template arguments */
12763 }
12766 {
12786 }
12811 /* Fall through. */
12814 {
12817 }
12818 else
12822 /* This is handled by tsubst_copy_and_build. */
12828 in_decl),
12832 /* We shouldn't have built any of these during initial template
12833 generation. Instead, they should be built during instantiation
12834 in response to the saved STMT_IS_FULL_EXPR_P setting. */
12838 r = build2
12858 {
12859 /* Instantiate any typedefs in the type. */
12864 }
12867 /* These can sometimes show up in a partial instantiation, but never
12868 involve template parms. */
12873 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
12876 }
12877 }
12879 /* Like tsubst_copy, but specifically for OpenMP clauses. */
12881 static tree
12884 {
12888 {
12894 {
12897 {
12903 }
12904 /* FALLTHRU */
12932 {
12935 {
12942 }
12943 else
12945 }
12975 }
12976 }
12982 }
12984 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
12986 static tree
12988 tree in_decl)
12989 {
12990 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
13010 {
13013 else
13014 {
13018 }
13019 }
13024 #undef RECUR
13025 }
13027 /* Substitute one OMP_FOR iterator. */
13029 static void
13034 {
13035 #define RECUR(NODE) \
13036 tsubst_expr ((NODE), args, complain, in_decl, \
13037 integral_constant_expression_p)
13045 /* Do this before substituting into decl to handle 'auto'. */
13054 {
13058 }
13063 {
13070 complain);
13071 else
13078 }
13081 {
13082 tree c;
13084 {
13095 }
13097 {
13102 {
13105 }
13106 }
13107 }
13113 else
13117 {
13128 {
13135 }
13136 else
13142 {
13148 }
13152 {
13159 }
13160 else
13166 }
13172 #undef RECUR
13173 }
13175 /* Like tsubst_copy for expressions, etc. but also does semantic
13176 processing. */
13178 static tree
13181 {
13182 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13183 #define RECUR(NODE) \
13184 tsubst_expr ((NODE), args, complain, in_decl, \
13185 integral_constant_expression_p)
13188 tree r;
13189 location_t loc;
13201 {
13203 {
13204 tree_stmt_iterator i;
13208 }
13223 else
13232 {
13234 tree init;
13240 {
13243 tree decl;
13251 else
13253 }
13255 {
13256 /* Don't build up decls for a variadic capture proxy, we'll
13257 instantiate the elements directly as needed. */
13259 }
13260 else
13261 {
13265 {
13266 /* By marking the declaration as instantiated, we avoid
13267 trying to instantiate it. Since instantiate_decl can't
13268 handle local variables, and since we've already done
13269 all that needs to be done, that's the right thing to
13270 do. */
13275 /* Anonymous aggregates are a special case. */
13278 {
13281 {
13285 }
13287 }
13293 {
13298 }
13299 else
13300 {
13305 {
13306 /* For __PRETTY_FUNCTION__ we have to adjust the
13307 initializer. */
13311 }
13312 else
13313 {
13317 {
13318 /* If we had an initializer but it
13319 instantiated to nothing,
13320 value-initialize the object. This will
13321 only occur when the initializer was a
13322 pack expansion where the parameter packs
13323 used in that expansion were of length
13324 zero. */
13326 complain);
13329 }
13330 else
13332 }
13335 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
13338 }
13339 }
13340 }
13343 }
13358 {
13368 }
13395 {
13399 }
13407 else
13415 else
13442 {
13444 tree label;
13449 }
13455 /* Computed goto's must be tsubst'd into. On the other hand,
13456 non-computed gotos must not be; the identifier in question
13457 will have no binding. */
13459 else
13465 tmp = finish_asm_stmt
13472 {
13477 }
13482 {
13487 }
13488 else
13489 {
13494 else
13501 else
13507 else
13509 }
13513 {
13517 {
13519 /* Prevent instantiate_decl from trying to instantiate
13520 this variable. We've already done all that needs to be
13521 done. */
13524 }
13529 }
13535 {
13536 /* Local classes are not independent templates; they are
13537 instantiated along with their containing function. And this
13538 way we don't have to deal with pushing out of one local class
13539 to instantiate a member of another local class. */
13540 tree fn;
13541 /* Closures are handled by the LAMBDA_EXPR. */
13547 }
13551 {
13552 tree condition;
13555 condition =
13557 args,
13566 }
13590 {
13599 {
13604 }
13616 integral_constant_expression_p);
13625 else
13626 {
13634 }
13637 }
13682 {
13687 {
13690 }
13696 }
13697 else
13698 {
13705 {
13708 }
13711 {
13716 {
13719 }
13725 }
13726 else
13727 {
13731 }
13734 }
13738 {
13744 {
13748 {
13753 }
13757 }
13758 else
13759 {
13764 }
13765 }
13790 /* If the first operand was a statement, we're done with it. */
13794 complain));
13801 integral_constant_expression_p));
13802 }
13805 out:
13808 #undef RECUR
13809 #undef RETURN
13810 }
13812 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
13813 function. For description of the body see comment above
13814 cp_parser_omp_declare_reduction_exprs. */
13816 static void
13818 {
13824 tree_stmt_iterator tsi;
13835 {
13854 }
13856 {
13876 }
13877 }
13879 /* T is a postfix-expression that is not being used in a function
13880 call. Return the substituted version of T. */
13882 static tree
13884 tsubst_flags_t complain,
13885 tree in_decl)
13886 {
13890 else
13896 }
13898 /* Like tsubst but deals with expressions and performs semantic
13899 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
13901 tree
13903 tree args,
13904 tsubst_flags_t complain,
13905 tree in_decl,
13908 {
13909 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
13910 #define RECUR(NODE) \
13911 tsubst_copy_and_build (NODE, args, complain, in_decl, \
13913 integral_constant_expression_p)
13916 location_t loc;
13925 /* N3276 decltype magic only applies to calls at the top level or on the
13926 right side of a comma. */
13931 {
13934 /* Fall through. */
13936 {
13937 tree decl;
13938 cp_id_kind idk;
13943 {
13946 }
13948 /* Look up the name. */
13951 /* By convention, expressions use ERROR_MARK_NODE to indicate
13952 failure, not NULL_TREE. */
13958 integral_constant_expression_p,
13966 input_location);
13970 {
13974 }
13976 }
13979 {
13980 tree object;
13988 {
13991 }
13992 else
13999 else
14001 }
14004 {
14008 {
14009 /* A type conversion to reference type will be enclosed in
14010 such an indirect ref, but the substitution of the cast
14011 will have also added such an indirect ref. */
14014 }
14015 else
14019 }
14027 {
14034 flags));
14035 }
14048 {
14049 tree type;
14055 {
14060 }
14066 {
14084 }
14088 }
14122 else
14124 in_decl);
14159 {
14160 tree r;
14164 r = build_x_binary_op
14168 ? ERROR_MARK
14172 ? ERROR_MARK
14182 }
14199 {
14208 }
14212 /* Fall through */
14215 {
14216 tree r;
14222 {
14223 /* When there are no ARGS, we are trying to evaluate a
14224 non-dependent expression from the parser. Trying to do
14225 the substitutions may not work. */
14228 }
14229 else
14230 {
14235 else
14238 /*integral_constant_expression_p=*/
14242 }
14246 else
14250 {
14252 {
14254 {
14258 }
14259 else
14263 }
14265 }
14267 }
14270 {
14280 }
14294 {
14295 tree r;
14299 r = build_x_modify_expr
14305 /* TREE_NO_WARNING must be set if either the expression was
14306 parenthesized or it uses an operator such as >>= rather
14307 than plain assignment. In the former case, it was already
14308 set and must be copied. In the latter case,
14309 build_x_modify_expr sets it and it must not be reset
14310 here. */
14317 }
14322 /* Remember that there was a reference to this entity. */
14328 {
14333 tree ret;
14337 else
14338 {
14342 }
14344 /* If there was an initializer in the original tree, but it
14345 instantiated to an empty list, then we should pass a
14346 non-NULL empty vector to tell build_new that it was an
14347 empty initializer() rather than no initializer. This can
14348 only happen when the initializer is a pack expansion whose
14349 parameter packs are of length zero. */
14352 else
14353 {
14357 else
14358 {
14361 }
14362 }
14369 complain);
14377 }
14385 complain));
14388 {
14392 integral_constant_expression_p);
14394 op0,
14397 }
14400 {
14401 tree function;
14406 tree ret;
14409 /* When we parsed the expression, we determined whether or
14410 not Koenig lookup should be performed. */
14413 {
14418 }
14420 {
14421 /* Do nothing; calling tsubst_copy_and_build on an identifier
14422 would incorrectly perform unqualified lookup again.
14424 Note that we can also have an IDENTIFIER_NODE if the earlier
14425 unqualified lookup found a member function; in that case
14426 koenig_p will be false and we do want to do the lookup
14427 again to find the instantiated member function.
14429 FIXME but doing that causes c++/15272, so we need to stop
14430 using IDENTIFIER_NODE in that situation. */
14432 }
14433 else
14434 {
14436 {
14442 }
14443 else
14448 /* Avoid error about taking the address of a constructor. */
14452 in_decl,
14454 integral_constant_expression_p);
14458 }
14463 {
14468 else
14469 {
14470 /* Expand the pack expansion and push each entry onto
14471 CALL_ARGS. */
14474 {
14479 {
14484 }
14485 }
14486 else
14487 {
14488 /* A partial substitution. Add one entry. */
14490 }
14491 }
14492 }
14494 /* We do not perform argument-dependent lookup if normal
14495 lookup finds a non-function, in accordance with the
14496 expected resolution of DR 218. */
14499 /* If lookup found a member function, the Koenig lookup is
14500 not appropriate, even if an unqualified-name was used
14501 to denote the function. */
14504 /* Only do this when substitution turns a dependent call
14505 into a non-dependent call. */
14512 {
14514 {
14515 /* For backwards compatibility and good diagnostics, try
14516 the unqualified lookup again if we aren't in SFINAE
14517 context. */
14518 tree unq = (tsubst_copy_and_build
14520 integral_constant_expression_p));
14525 {
14534 "%qD was not declared in this scope, "
14535 "and no declarations were found by "
14536 "argument-dependent lookup at the point "
14538 {
14542 {
14544 input_location);
14546 "declarations in dependent base %qT are "
14552 else
14556 }
14557 else
14560 }
14562 }
14563 }
14565 {
14570 }
14571 }
14573 /* Remember that there was a reference to this entity. */
14577 /* Put back tf_decltype for the actual call. */
14582 complain);
14584 {
14599 complain);
14600 else
14601 ret = (build_new_method_call
14606 complain));
14607 }
14608 else
14611 koenig_p,
14612 complain);
14617 }
14620 {
14625 {
14627 {
14632 }
14633 else
14634 {
14639 }
14640 }
14641 else
14642 {
14645 }
14649 }
14656 input_location));
14659 {
14667 {
14668 /* We have pack expansions, so expand those and
14669 create a new list out of it. */
14672 tree chain;
14675 /* Expand the argument expressions. */
14683 /* Build the rest of the list. */
14688 /* Determine the number of arguments. */
14690 {
14693 }
14696 else
14697 {
14698 /* Since we only performed a partial substitution into
14699 the argument pack, we only RETURN (a single list
14700 node. */
14707 }
14709 /* Convert the argument vectors into a TREE_LIST */
14712 {
14713 /* Grab the Ith values. */
14714 i--;
14717 value
14721 /* Build the list (backwards). */
14723 }
14726 }
14742 }
14745 {
14746 tree object;
14747 tree object_type;
14748 tree member;
14752 /* Remember that there was a reference to this entity. */
14762 else
14770 {
14772 {
14777 {
14780 }
14782 {
14787 }
14788 }
14789 }
14792 {
14793 /* Lookup the template functions now that we know what the
14794 scope is. */
14802 {
14805 args);
14806 member = (adjust_result_of_qualified_name_lookup
14808 object_type));
14809 }
14810 else
14811 {
14813 input_location);
14815 }
14816 }
14820 {
14822 {
14826 else
14829 }
14831 }
14837 complain));
14838 }
14845 {
14853 tree r;
14858 /* digest_init will do the wrong thing if we let it. */
14862 /* We do not want to process the index of aggregate
14863 initializers as they are identifier nodes which will be
14864 looked up by digest_init. */
14870 {
14872 /* An identifier index is looked up in the type
14873 being initialized, not the current scope. */
14878 {
14879 /* Substitute into the pack expansion. */
14881 in_decl);
14885 ;
14887 /* Just move the argument into place. */
14889 else
14890 {
14891 /* Update the length of the final CONSTRUCTOR
14892 arguments vector, and note that we will need to
14893 copy.*/
14896 }
14897 }
14898 else
14900 }
14903 {
14908 {
14910 {
14915 }
14916 else
14918 }
14919 }
14929 }
14932 {
14935 {
14938 }
14939 else
14940 {
14943 }
14944 }
14950 {
14951 /* We don't build decls for an instantiation of a
14952 variadic capture proxy, we instantiate the elements
14953 when needed. */
14956 }
14957 /* Fall through */
14960 {
14964 /* If the original type was a reference, we'll be wrapped in
14965 the appropriate INDIRECT_REF. */
14968 }
14979 {
14988 }
14991 {
14997 integral_constant_expression_p);
15001 /* If the resulting list of expression statement is empty,
15002 fold it further into void_zero_node. */
15007 }
15010 {
15024 /* For a function scope, we want to use tsubst so that we don't
15025 complain about referring to an auto function before its return
15026 type has been deduced. Otherwise, we want to use tsubst_copy so
15027 that we look up the existing field/parameter/variable rather
15028 than build a new one. */
15033 {
15034 /* Look up the parameter we want directly, as tsubst_copy
15035 doesn't do what we need. */
15041 /* FIXME Work around the parm not having DECL_CONTEXT set. */
15044 }
15045 else
15054 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
15056 /* Now that we know visibility, instantiate the type so we have a
15057 declaration of the op() for later calls to lambda_function. */
15063 }
15066 /* We can get here for a constant initializer of non-dependent type.
15067 FIXME stop folding in cp_parser_initializer_clause. */
15068 {
15070 complain);
15072 }
15076 integral_constant_expression_p));
15086 complain));
15089 /* Handle Objective-C++ constructs, if appropriate. */
15090 {
15091 tree subst
15096 }
15098 }
15100 #undef RECUR
15101 #undef RETURN
15102 out:
15105 }
15107 /* Verify that the instantiated ARGS are valid. For type arguments,
15108 make sure that the type's linkage is ok. For non-type arguments,
15109 make sure they are constants if they are integral or enumerations.
15110 Emit an error under control of COMPLAIN, and return TRUE on error. */
15112 static bool
15114 {
15118 {
15128 }
15130 {
15131 /* [basic.link]: A name with no linkage (notably, the name
15132 of a class or enumeration declared in a local scope)
15133 shall not be used to declare an entity with linkage.
15134 This implies that names with no linkage cannot be used as
15135 template arguments
15137 DR 757 relaxes this restriction for C++0x. */
15142 {
15143 /* DR 488 makes use of a type with no linkage cause
15144 type deduction to fail. */
15146 {
15149 else
15152 }
15154 }
15155 /* In order to avoid all sorts of complications, we do not
15156 allow variably-modified types as template arguments. */
15158 {
15162 }
15163 }
15164 /* Class template and alias template arguments should be OK. */
15166 ;
15167 /* A non-type argument of integral or enumerated type must be a
15168 constant. */
15172 {
15176 }
15178 }
15180 static bool
15182 {
15187 {
15190 }
15194 }
15196 /* We're out of SFINAE context now, so generate diagnostics for the access
15197 errors we saw earlier when instantiating D from TMPL and ARGS. */
15199 static void
15201 {
15213 }
15215 /* Instantiate the indicated variable, function, or alias template TMPL with
15216 the template arguments in TARG_PTR. */
15218 static tree
15220 {
15222 tree fndecl;
15223 tree gen_tmpl;
15224 tree spec;
15232 /* If this function is a clone, handle it specially. */
15234 {
15235 tree spec;
15236 tree clone;
15238 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
15239 DECL_CLONED_FUNCTION. */
15245 /* Look for the clone. */
15249 /* We should always have found the clone by now. */
15252 }
15254 /* Check to see if we already have this specialization. */
15257 /* The TMPL is a partial instantiation. To get a full set of
15258 arguments we must add the arguments used to perform the
15259 partial instantiation. */
15261 targ_ptr);
15263 /* It would be nice to avoid hashing here and then again in tsubst_decl,
15264 but it doesn't seem to be on the hot path. */
15273 {
15275 {
15279 }
15281 }
15284 complain))
15287 /* We are building a FUNCTION_DECL, during which the access of its
15288 parameters and return types have to be checked. However this
15289 FUNCTION_DECL which is the desired context for access checking
15290 is not built yet. We solve this chicken-and-egg problem by
15291 deferring all checks until we have the FUNCTION_DECL. */
15294 /* Instantiation of the function happens in the context of the function
15295 template, not the context of the overload resolution we're doing. */
15297 /* If there are dependent arguments, e.g. because we're doing partial
15298 ordering, make sure processing_template_decl stays set. */
15302 {
15306 }
15307 /* Substitute template parameters to obtain the specialization. */
15315 {
15318 }
15320 /* The DECL_TI_TEMPLATE should always be the immediate parent
15321 template, not the most general template. */
15324 /* Now we know the specialization, compute access previously
15325 deferred. */
15332 /* If we've just instantiated the main entry point for a function,
15333 instantiate all the alternate entry points as well. We do this
15334 by cloning the instantiation of the main entry point, not by
15335 instantiating the template clones. */
15340 {
15342 {
15343 /* Remember to reinstantiate when we're out of SFINAE so the user
15344 can see the errors. */
15346 }
15348 }
15350 }
15352 /* Wrapper for instantiate_template_1. */
15354 tree
15356 {
15357 tree ret;
15362 }
15364 /* Instantiate the alias template TMPL with ARGS. Also push a template
15365 instantiation level, which instantiate_template doesn't do because
15366 functions and variables have sufficient context established by the
15367 callers. */
15369 static tree
15371 {
15378 {
15381 }
15383 args =
15391 /* We can't free this if a pending_template entry or last_error_tinst_level
15392 is pointing at it. */
15398 }
15400 /* PARM is a template parameter pack for FN. Returns true iff
15401 PARM is used in a deducible way in the argument list of FN. */
15403 static bool
15405 {
15408 {
15410 tree packs;
15416 {
15417 /* The template parameter pack is used in a function parameter
15418 pack. If this is the end of the parameter list, the
15419 template parameter pack is deducible. */
15422 else
15423 /* Otherwise, not. Well, it could be deduced from
15424 a non-pack parameter, but doing so would end up with
15425 a deduction mismatch, so don't bother. */
15427 }
15428 }
15429 /* The template parameter pack isn't used in any function parameter
15430 packs, but it might be used deeper, e.g. tuple<Args...>. */
15432 }
15434 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
15435 NARGS elements of the arguments that are being used when calling
15436 it. TARGS is a vector into which the deduced template arguments
15437 are placed.
15439 Returns either a FUNCTION_DECL for the matching specialization of FN or
15440 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
15441 true, diagnostics will be printed to explain why it failed.
15443 If FN is a conversion operator, or we are trying to produce a specific
15444 specialization, RETURN_TYPE is the return type desired.
15446 The EXPLICIT_TARGS are explicit template arguments provided via a
15447 template-id.
15449 The parameter STRICT is one of:
15451 DEDUCE_CALL:
15452 We are deducing arguments for a function call, as in
15453 [temp.deduct.call].
15455 DEDUCE_CONV:
15456 We are deducing arguments for a conversion function, as in
15457 [temp.deduct.conv].
15459 DEDUCE_EXACT:
15460 We are deducing arguments when doing an explicit instantiation
15461 as in [temp.explicit], when determining an explicit specialization
15462 as in [temp.expl.spec], or when taking the address of a function
15463 template, as in [temp.deduct.funcaddr]. */
15465 tree
15467 tree explicit_targs,
15468 tree targs,
15471 tree return_type,
15472 unification_kind_t strict,
15476 {
15477 tree parms;
15478 tree fntype;
15486 tree tinst;
15492 /* In C++0x, it's possible to have a function template whose type depends
15493 on itself recursively. This is most obvious with decltype, but can also
15494 occur with enumeration scope (c++/48969). So we need to catch infinite
15495 recursion and reject the substitution at deduction time; this function
15496 will return error_mark_node for any repeated substitution.
15498 This also catches excessive recursion such as when f<N> depends on
15499 f<N-1> across all integers, and returns error_mark_node for all the
15500 substitutions back up to the initial one.
15502 This is, of course, not reentrant. */
15512 {
15513 /* [temp.deduct]
15515 The specified template arguments must match the template
15516 parameters in kind (i.e., type, nontype, template), and there
15517 must not be more arguments than there are parameters;
15518 otherwise type deduction fails.
15520 Nontype arguments must match the types of the corresponding
15521 nontype template parameters, or must be convertible to the
15522 types of the corresponding nontype parameters as specified in
15523 _temp.arg.nontype_, otherwise type deduction fails.
15525 All references in the function type of the function template
15526 to the corresponding template parameters are replaced by the
15527 specified template argument values. If a substitution in a
15528 template parameter or in the function type of the function
15529 template results in an invalid type, type deduction fails. */
15534 /* Adjust any explicit template arguments before entering the
15535 substitution context. */
15536 explicit_targs
15538 complain,
15544 /* Substitute the explicit args into the function type. This is
15545 necessary so that, for instance, explicitly declared function
15546 arguments can match null pointed constants. If we were given
15547 an incomplete set of explicit args, we must not do semantic
15548 processing during substitution as we could create partial
15549 instantiations. */
15551 {
15556 /* Dig out the actual parm. */
15559 {
15562 }
15564 {
15567 }
15570 /* No explicit argument for this template parameter. */
15574 {
15575 /* Mark the argument pack as "incomplete". We could
15576 still deduce more arguments during unification.
15577 We remove this mark in type_unification_real. */
15579 {
15583 }
15585 /* We have some incomplete argument packs. */
15587 }
15588 }
15592 {
15595 }
15598 /* Ignore any access checks; we'll see them again in
15599 instantiate_template and they might have the wrong
15600 access path at this point. */
15612 /* Place the explicitly specified arguments in TARGS. */
15615 }
15617 /* Never do unification on the 'this' parameter. */
15621 {
15630 }
15632 /* We allow incomplete unification without an error message here
15633 because the standard doesn't seem to explicitly prohibit it. Our
15634 callers must be ready to deal with unification failures in any
15635 event. */
15638 /* If we aren't explaining yet, push tinst context so we can see where
15639 any errors (e.g. from class instantiations triggered by instantiation
15640 of default template arguments) come from. If we are explaining, this
15641 context is redundant. */
15643 {
15646 }
15648 /* type_unification_real will pass back any access checks from default
15649 template argument substitution. */
15661 /* Now that we have bindings for all of the template arguments,
15662 ensure that the arguments deduced for the template template
15663 parameters have compatible template parameter lists. We cannot
15664 check this property before we have deduced all template
15665 arguments, because the template parameter types of a template
15666 template parameter might depend on prior template parameters
15667 deduced after the template template parameter. The following
15668 ill-formed example illustrates this issue:
15670 template<typename T, template<T> class C> void f(C<5>, T);
15672 template<int N> struct X {};
15674 void g() {
15675 f(X<5>(), 5l); // error: template argument deduction fails
15676 }
15678 The template parameter list of 'C' depends on the template type
15679 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
15680 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
15681 time that we deduce 'C'. */
15684 {
15687 }
15689 /* All is well so far. Now, check:
15691 [temp.deduct]
15693 When all template arguments have been deduced, all uses of
15694 template parameters in nondeduced contexts are replaced with
15695 the corresponding deduced argument values. If the
15696 substitution results in an invalid type, as described above,
15697 type deduction fails. */
15700 {
15703 }
15705 /* Also collect access checks from the instantiation. */
15718 /* Now perform any access checks encountered during substitution. */
15725 /* If we're looking for an exact match, check that what we got
15726 is indeed an exact match. It might not be if some template
15727 parameters are used in non-deduced contexts. */
15729 {
15733 tree sarg
15739 {
15743 }
15744 }
15748 fail:
15751 {
15753 /* Reset once we're all the way out. */
15755 }
15757 /* We can't free this if a pending_template entry or last_error_tinst_level
15758 is pointing at it. */
15764 }
15766 /* Adjust types before performing type deduction, as described in
15767 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
15768 sections are symmetric. PARM is the type of a function parameter
15769 or the return type of the conversion function. ARG is the type of
15770 the argument passed to the call, or the type of the value
15771 initialized with the result of the conversion function.
15772 ARG_EXPR is the original argument expression, which may be null. */
15774 static int
15778 tree arg_expr)
15779 {
15783 {
15788 {
15789 /* Swap PARM and ARG throughout the remainder of this
15790 function; the handling is precisely symmetric since PARM
15791 will initialize ARG rather than vice versa. */
15796 }
15799 /* Core issue #873: Do the DR606 thing (see below) for these cases,
15800 too, but here handle it by stripping the reference from PARM
15801 rather than by adding it to ARG. */
15809 /* Nothing else to do in this case. */
15814 }
15817 {
15818 /* [temp.deduct.call]
15820 If P is not a reference type:
15822 --If A is an array type, the pointer type produced by the
15823 array-to-pointer standard conversion (_conv.array_) is
15824 used in place of A for type deduction; otherwise,
15826 --If A is a function type, the pointer type produced by
15827 the function-to-pointer standard conversion
15828 (_conv.func_) is used in place of A for type deduction;
15829 otherwise,
15831 --If A is a cv-qualified type, the top level
15832 cv-qualifiers of A's type are ignored for type
15833 deduction. */
15838 else
15840 }
15842 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
15843 of the form T&&, where T is a template parameter, and the argument
15844 is an lvalue, T is deduced as A& */
15850 /* try_one_overload doesn't provide an arg_expr, but
15851 functions are always lvalues. */
15855 /* [temp.deduct.call]
15857 If P is a cv-qualified type, the top level cv-qualifiers
15858 of P's type are ignored for type deduction. If P is a
15859 reference type, the type referred to by P is used for
15860 type deduction. */
15863 {
15866 }
15868 /* DR 322. For conversion deduction, remove a reference type on parm
15869 too (which has been swapped into ARG). */
15874 }
15876 /* Subroutine of unify_one_argument. PARM is a function parameter of a
15877 template which does contain any deducible template parameters; check if
15878 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
15879 unify_one_argument. */
15881 static int
15884 {
15885 tree type;
15889 else
15896 {
15900 }
15902 {
15907 }
15911 else
15913 }
15917 /* Returns true iff the expression EXPR is one from which a template
15918 argument can be deduced. In other words, if it's an undecorated
15919 use of a template non-type parameter. */
15921 static bool
15923 {
15925 }
15927 /* Returns true iff the array domain DOMAIN uses a template parameter in a
15928 deducible way; that is, if it has a max value of <PARM> - 1. */
15930 static bool
15932 {
15941 }
15943 /* Returns true iff the template arguments ARGS use a template parameter
15944 in a deducible way. */
15946 static bool
15948 {
15950 {
15955 else
15956 {
15963 else
15965 }
15968 }
15970 }
15972 /* Returns true iff TYPE contains any deducible references to template
15973 parameters, as per 14.8.2.5. */
15975 static bool
15977 {
15981 /* T
15982 cv-list T
15983 TT<T>
15984 TT<i>
15985 TT<> */
15990 /* T*
15991 T&
15992 T&& */
15996 /* T[integer-constant ]
15997 type [i] */
16002 /* T type ::*
16003 type T::*
16004 T T::*
16005 T (type ::*)()
16006 type (T::*)()
16007 type (type ::*)(T)
16008 type (T::*)(T)
16009 T (type ::*)(T)
16010 T (T::*)()
16011 T (T::*)(T) */
16014 || (uses_deducible_template_parms
16017 /* template-name <T> (where template-name refers to a class template)
16018 template-name <i> (where template-name refers to a class template) */
16025 /* type (T)
16026 T()
16027 T(T) */
16030 {
16039 }
16042 }
16044 /* Subroutine of type_unification_real and unify_pack_expansion to
16045 handle unification of a single P/A pair. Parameters are as
16046 for those functions. */
16048 static int
16052 {
16059 /* We can't deduce anything from this, but we might get all the
16060 template args from other function args. */
16063 /* Implicit conversions (Clause 4) will be performed on a function
16064 argument to convert it to the type of the corresponding function
16065 parameter if the parameter type contains no template-parameters that
16066 participate in template argument deduction. */
16068 /* For function parameters that contain no template-parameters at all,
16069 we have historically checked for convertibility in order to shortcut
16070 consideration of this candidate. */
16072 explain_p);
16075 /* For function parameters with only non-deducible template parameters,
16076 just return. */
16080 {
16082 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
16083 | UNIFY_ALLOW_MORE_CV_QUAL
16097 }
16099 /* We only do these transformations if this is the top-level
16100 parameter_type_list in a call or declaration matching; in other
16101 situations (nested function declarators, template argument lists) we
16102 won't be comparing a type to an expression, and we don't do any type
16103 adjustments. */
16105 {
16107 {
16110 {
16111 /* [temp.deduct.type] A template-argument can be
16112 deduced from a pointer to function or pointer
16113 to member function argument if the set of
16114 overloaded functions does not contain function
16115 templates and at most one of a set of
16116 overloaded functions provides a unique
16117 match. */
16124 }
16130 }
16132 arg_strict |=
16134 }
16135 else
16139 /* For deduction from an init-list we need the actual list. */
16143 }
16145 /* Most parms like fn_type_unification.
16147 If SUBR is 1, we're being called recursively (to unify the
16148 arguments of a function or method parameter of a function
16149 template).
16151 CHECKS is a pointer to a vector of access checks encountered while
16152 substituting default template arguments. */
16154 static int
16156 tree targs,
16157 tree xparms,
16161 unification_kind_t strict,
16165 {
16170 tree parms;
16179 /* Reset the number of non-defaulted template arguments contained
16180 in TARGS. */
16183 again:
16191 {
16196 /* For a function parameter pack that occurs at the end of the
16197 parameter-declaration-list, the type A of each remaining
16198 argument of the call is compared with the type P of the
16199 declarator-id of the function parameter pack. */
16205 /* For a function parameter pack that does not occur at the
16206 end of the parameter-declaration-list, the type of the
16207 parameter pack is a non-deduced context. */
16216 }
16221 {
16222 /* Unify the remaining arguments with the pack expansion type. */
16223 tree argvec;
16226 /* Allocate a TREE_VEC and copy in all of the arguments */
16231 /* Copy the parameter into parmvec. */
16237 /* Advance to the end of the list of parameters. */
16239 }
16241 /* Fail if we've reached the end of the parm list, and more args
16242 are present, and the parm list isn't variadic. */
16245 /* Fail if parms are left and they don't have default values. */
16248 {
16252 {
16253 count++;
16255 }
16257 }
16260 {
16261 tsubst_flags_t complain = (explain_p
16262 ? tf_warning_or_error
16266 {
16270 /* Clear the "incomplete" flags on all argument packs now so that
16271 substituting them into later default arguments works. */
16273 {
16276 }
16282 /* If this is an undeduced nontype parameter that depends on
16283 a type parameter, try another pass; its type may have been
16284 deduced from a later argument than the one from which
16285 this parameter can be deduced. */
16291 /* Core issue #226 (C++0x) [temp.deduct]:
16293 If a template argument has not been deduced, its
16294 default template argument, if any, is used.
16296 When we are in C++98 mode, TREE_PURPOSE will either
16297 be NULL_TREE or ERROR_MARK_NODE, so we do not need
16298 to explicitly check cxx_dialect here. */
16300 {
16315 else
16316 {
16318 /* The position of the first default template argument,
16319 is also the number of non-defaulted arguments in TARGS.
16320 Record that. */
16324 }
16325 }
16327 /* If the type parameter is a parameter pack, then it will
16328 be deduced to an empty parameter pack. */
16330 {
16331 tree arg;
16334 {
16338 }
16339 else
16346 }
16349 }
16350 }
16351 #ifdef ENABLE_CHECKING
16354 #endif
16357 }
16359 /* Subroutine of type_unification_real. Args are like the variables
16360 at the call site. ARG is an overloaded function (or template-id);
16361 we try deducing template args from each of the overloads, and if
16362 only one succeeds, we go with that. Modifies TARGS and returns
16363 true on success. */
16365 static bool
16367 tree targs,
16368 tree parm,
16369 tree arg,
16370 unification_kind_t strict,
16373 {
16380 {
16383 }
16384 else
16388 /* Handle `&x' where `x' is some static or non-static member
16389 function name. */
16395 /* Strip baselink information. */
16400 {
16401 /* If we got some explicit template args, we need to plug them into
16402 the affected templates before we try to unify, in case the
16403 explicit args will completely resolve the templates in question. */
16410 {
16423 {
16428 {
16431 }
16432 }
16435 }
16436 /* If no templates (or more than one) are fully resolved by the
16437 explicit arguments, this template-id is a non-deduced context; it
16438 could still be OK if we deduce all template arguments for the
16439 enclosing call through other arguments. */
16442 }
16445 /* If ARG is, for example, "(0, &f)" then its type will be unknown
16446 -- but the deduction does not succeed because the expression is
16447 not just the function on its own. */
16449 else
16455 {
16458 }
16460 /* [temp.deduct.type] A template-argument can be deduced from a pointer
16461 to function or pointer to member function argument if the set of
16462 overloaded functions does not contain function templates and at most
16463 one of a set of overloaded functions provides a unique match.
16465 So if we found multiple possibilities, we return success but don't
16466 deduce anything. */
16469 {
16474 }
16479 }
16481 /* Core DR 115: In contexts where deduction is done and fails, or in
16482 contexts where deduction is not done, if a template argument list is
16483 specified and it, along with any default template arguments, identifies
16484 a single function template specialization, then the template-id is an
16485 lvalue for the function template specialization. */
16487 tree
16489 {
16502 {
16505 }
16507 {
16510 }
16512 {
16515 }
16518 {
16522 /* If we got some explicit template args, we need to plug them into
16523 the affected templates before we try to unify, in case the
16524 explicit args will completely resolve the templates in question. */
16532 {
16545 {
16548 {
16551 }
16553 {
16556 }
16557 }
16558 }
16560 {
16568 {
16569 tree base
16572 }
16576 }
16578 /* There were no good options and at least one bad one, so let the
16579 user know what the problem is. */
16581 }
16583 }
16585 /* Subroutine of resolve_overloaded_unification; does deduction for a single
16586 overload. Fills TARGS with any deduced arguments, or error_mark_node if
16587 different overloads deduce different arguments for a given parm.
16588 ADDR_P is true if the expression for which deduction is being
16589 performed was of the form "& fn" rather than simply "fn".
16591 Returns 1 on success. */
16593 static int
16595 tree orig_targs,
16596 tree targs,
16597 tree parm,
16598 tree arg,
16599 unification_kind_t strict,
16603 {
16605 tree tempargs;
16611 /* [temp.deduct.type] A template-argument can be deduced from a pointer
16612 to function or pointer to member function argument if the set of
16613 overloaded functions does not contain function templates and at most
16614 one of a set of overloaded functions provides a unique match.
16616 So if this is a template, just return success. */
16628 /* We don't copy orig_targs for this because if we have already deduced
16629 some template args from previous args, unify would complain when we
16630 try to deduce a template parameter for the same argument, even though
16631 there isn't really a conflict. */
16638 /* First make sure we didn't deduce anything that conflicts with
16639 explicitly specified args. */
16641 {
16648 /* Since we're unifying against ourselves, we will fill in
16649 template args used in the function parm list with our own
16650 template parms. Discard them. */
16654 }
16657 {
16662 }
16665 }
16667 /* PARM is a template class (perhaps with unbound template
16668 parameters). ARG is a fully instantiated type. If ARG can be
16669 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
16670 TARGS are as for unify. */
16672 static tree
16675 {
16676 tree copy_of_targs;
16683 /* We need to make a new template argument vector for the call to
16684 unify. If we used TARGS, we'd clutter it up with the result of
16685 the attempted unification, even if this class didn't work out.
16686 We also don't want to commit ourselves to all the unifications
16687 we've already done, since unification is supposed to be done on
16688 an argument-by-argument basis. In other words, consider the
16689 following pathological case:
16691 template <int I, int J, int K>
16692 struct S {};
16694 template <int I, int J>
16695 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
16697 template <int I, int J, int K>
16698 void f(S<I, J, K>, S<I, I, I>);
16700 void g() {
16701 S<0, 0, 0> s0;
16702 S<0, 1, 2> s2;
16704 f(s0, s2);
16705 }
16707 Now, by the time we consider the unification involving `s2', we
16708 already know that we must have `f<0, 0, 0>'. But, even though
16709 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
16710 because there are two ways to unify base classes of S<0, 1, 2>
16711 with S<I, I, I>. If we kept the already deduced knowledge, we
16712 would reject the possibility I=1. */
16715 /* If unification failed, we're done. */
16721 }
16723 /* Given a template type PARM and a class type ARG, find the unique
16724 base type in ARG that is an instance of PARM. We do not examine
16725 ARG itself; only its base-classes. If there is not exactly one
16726 appropriate base class, return NULL_TREE. PARM may be the type of
16727 a partial specialization, as well as a plain template type. Used
16728 by unify. */
16730 static enum template_base_result
16733 {
16735 tree binfo;
16741 {
16742 /* The type could not be completed. */
16745 }
16747 /* Walk in inheritance graph order. The search order is not
16748 important, and this avoids multiple walks of virtual bases. */
16750 {
16755 {
16756 /* If there is more than one satisfactory baseclass, then:
16758 [temp.deduct.call]
16760 If they yield more than one possible deduced A, the type
16761 deduction fails.
16763 applies. */
16765 {
16768 }
16771 }
16772 }
16776 }
16778 /* Returns the level of DECL, which declares a template parameter. */
16780 static int
16782 {
16784 {
16794 }
16796 }
16798 /* Decide whether ARG can be unified with PARM, considering only the
16799 cv-qualifiers of each type, given STRICT as documented for unify.
16800 Returns nonzero iff the unification is OK on that basis. */
16802 static int
16804 {
16810 {
16811 /* Although a CVR qualifier is ignored when being applied to a
16812 substituted template parameter ([8.3.2]/1 for example), that
16813 does not allow us to unify "const T" with "int&" because both
16814 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
16815 It is ok when we're allowing additional CV qualifiers
16816 at the outer level [14.8.2.1]/3,1st bullet. */
16826 }
16837 }
16839 /* Determines the LEVEL and INDEX for the template parameter PARM. */
16840 void
16842 {
16846 {
16849 }
16850 else
16851 {
16854 }
16855 }
16857 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
16858 do { \
16859 if (unify (TP, TA, P, A, S, EP)) \
16860 return 1; \
16861 } while (0);
16863 /* Unifies the remaining arguments in PACKED_ARGS with the pack
16864 expansion at the end of PACKED_PARMS. Returns 0 if the type
16865 deduction succeeds, 1 otherwise. STRICT is the same as in
16866 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
16867 call argument list. We'll need to adjust the arguments to make them
16868 types. SUBR tells us if this is from a recursive call to
16869 type_unification_real, or for comparing two template argument
16870 lists. */
16872 static int
16876 {
16877 tree parm
16884 /* Determine the parameter packs we will be deducing from the
16885 pattern, and record their current deductions. */
16888 {
16892 /* Determine the index and level of this parameter pack. */
16895 /* Keep track of the parameter packs and their corresponding
16896 argument packs. */
16899 }
16901 /* Loop through all of the arguments that have not yet been
16902 unified and unify each with the pattern. */
16904 {
16905 tree parm;
16909 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
16910 or the element of its argument pack at the current index if
16911 this argument was explicitly specified. */
16913 {
16922 {
16925 }
16927 }
16929 /* If we had explicit template arguments, substitute them into the
16930 pattern before deduction. */
16932 {
16933 /* Some arguments might still be unspecified or dependent. */
16941 NULL_TREE);
16946 }
16947 else
16950 /* Unify the pattern with the current argument. */
16955 /* For each parameter pack, collect the deduced value. */
16957 {
16963 }
16964 }
16966 /* Verify that the results of unification with the parameter packs
16967 produce results consistent with what we've seen before, and make
16968 the deduced argument packs available. */
16970 {
16977 /* By default keep the original deduced argument pack.
16978 If necessary, more specific code is going to update the
16979 resulting deduced argument later down in this function. */
16983 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
16984 actually deduce anything. */
16992 {
16993 /* If we had fewer function args than explicit template args,
16994 just use the explicits. */
16999 }
17002 {
17003 tree result;
17004 /* Build the deduced *_ARGUMENT_PACK. */
17006 {
17011 }
17012 else
17017 /* Note the deduced argument packs for this parameter
17018 pack. */
17020 }
17024 {
17025 /* We only had the explicitly-provided arguments before, but
17026 now we have a complete set of arguments. */
17032 }
17033 else
17034 {
17040 /* Inconsistent unification of this parameter pack. */
17042 bad_old_arg,
17043 bad_new_arg);
17044 }
17045 }
17048 }
17050 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
17051 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
17052 parameters and return value are as for unify. */
17054 static int
17058 {
17059 tree parm_max;
17060 tree arg_max;
17064 /* Our representation of array types uses "N - 1" as the
17065 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
17066 not an integer constant. We cannot unify arbitrarily
17067 complex expressions, so we eliminate the MINUS_EXPRs
17068 here. */
17072 {
17075 }
17079 {
17080 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
17081 trying to unify the type of a variable with the type
17082 of a template parameter. For example:
17084 template <unsigned int N>
17085 void f (char (&) [N]);
17086 int g();
17087 void h(int i) {
17088 char a[g(i)];
17089 f(a);
17090 }
17092 Here, the type of the ARG will be "int [g(i)]", and
17093 may be a SAVE_EXPR, etc. */
17097 }
17099 /* If only one of the bounds used a MINUS_EXPR, compensate
17100 by adding one to the other bound. */
17103 integer_type_node,
17104 parm_max,
17105 integer_one_node);
17108 integer_type_node,
17109 arg_max,
17110 integer_one_node);
17114 }
17116 /* Deduce the value of template parameters. TPARMS is the (innermost)
17117 set of template parameters to a template. TARGS is the bindings
17118 for those template parameters, as determined thus far; TARGS may
17119 include template arguments for outer levels of template parameters
17120 as well. PARM is a parameter to a template function, or a
17121 subcomponent of that parameter; ARG is the corresponding argument.
17122 This function attempts to match PARM with ARG in a manner
17123 consistent with the existing assignments in TARGS. If more values
17124 are deduced, then TARGS is updated.
17126 Returns 0 if the type deduction succeeds, 1 otherwise. The
17127 parameter STRICT is a bitwise or of the following flags:
17129 UNIFY_ALLOW_NONE:
17130 Require an exact match between PARM and ARG.
17131 UNIFY_ALLOW_MORE_CV_QUAL:
17132 Allow the deduced ARG to be more cv-qualified (by qualification
17133 conversion) than ARG.
17134 UNIFY_ALLOW_LESS_CV_QUAL:
17135 Allow the deduced ARG to be less cv-qualified than ARG.
17136 UNIFY_ALLOW_DERIVED:
17137 Allow the deduced ARG to be a template base class of ARG,
17138 or a pointer to a template base class of the type pointed to by
17139 ARG.
17140 UNIFY_ALLOW_INTEGER:
17141 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
17142 case for more information.
17143 UNIFY_ALLOW_OUTER_LEVEL:
17144 This is the outermost level of a deduction. Used to determine validity
17145 of qualification conversions. A valid qualification conversion must
17146 have const qualified pointers leading up to the inner type which
17147 requires additional CV quals, except at the outer level, where const
17148 is not required [conv.qual]. It would be normal to set this flag in
17149 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
17150 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
17151 This is the outermost level of a deduction, and PARM can be more CV
17152 qualified at this point.
17153 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
17154 This is the outermost level of a deduction, and PARM can be less CV
17155 qualified at this point. */
17157 static int
17160 {
17162 tree targ;
17163 tree tparm;
17166 /* I don't think this will do the right thing with respect to types.
17167 But the only case I've seen it in so far has been array bounds, where
17168 signedness is the only information lost, and I think that will be
17169 okay. */
17177 /* We can't deduce anything from this, but we might get all the
17178 template args from other function args. */
17181 /* If PARM uses template parameters, then we can't bail out here,
17182 even if ARG == PARM, since we won't record unifications for the
17183 template parameters. We might need them if we're trying to
17184 figure out which of two things is more specialized. */
17188 /* Handle init lists early, so the rest of the function can assume
17189 we're dealing with a type. */
17191 {
17196 /* Replace T with std::initializer_list<T> for deduction. */
17203 /* We can only deduce from an initializer list argument if the
17204 parameter is std::initializer_list or an array; otherwise this
17205 is a non-deduced context. */
17210 else
17214 {
17221 {
17223 /* It should only be possible to get here for a call. */
17225 elt_strict |= maybe_adjust_types_for_deduction
17228 }
17231 explain_p);
17232 }
17235 {
17236 /* Also deduce from the length of the initializer list. */
17242 }
17244 /* If the std::initializer_list<T> deduction worked, replace the
17245 deduced A with std::initializer_list<A>. */
17247 {
17252 }
17254 }
17256 /* Immediately reject some pairs that won't unify because of
17257 cv-qualification mismatches. */
17260 /* It is the elements of the array which hold the cv quals of an array
17261 type, and the elements might be template type parms. We'll check
17262 when we recurse. */
17264 /* We check the cv-qualifiers when unifying with template type
17265 parameters below. We want to allow ARG `const T' to unify with
17266 PARM `T' for example, when computing which of two templates
17267 is more specialized, for example. */
17281 {
17285 /* In a type which contains a nested-name-specifier, template
17286 argument values cannot be deduced for template parameters used
17287 within the nested-name-specifier. */
17299 /* The PARM is not one we're trying to unify. Just check
17300 to see if it matches ARG. */
17301 {
17306 else
17308 }
17315 /* Check for mixed types and values. */
17323 {
17324 /* ARG must be constructed from a template class or a template
17325 template parameter. */
17330 {
17334 tree parm_parms
17335 = DECL_INNERMOST_TEMPLATE_PARMS
17340 /* The resolution to DR150 makes clear that default
17341 arguments for an N-argument may not be used to bind T
17342 to a template template parameter with fewer than N
17343 parameters. It is not safe to permit the binding of
17344 default arguments as an extension, as that may change
17345 the meaning of a conforming program. Consider:
17347 struct Dense { static const unsigned int dim = 1; };
17349 template <template <typename> class View,
17350 typename Block>
17351 void operator+(float, View<Block> const&);
17353 template <typename Block,
17354 unsigned int Dim = Block::dim>
17355 struct Lvalue_proxy { operator float() const; };
17357 void
17358 test_1d (void) {
17359 Lvalue_proxy<Dense> p;
17360 float b;
17361 b + p;
17362 }
17364 Here, if Lvalue_proxy is permitted to bind to View, then
17365 the global operator+ will be used; if they are not, the
17366 Lvalue_proxy will be converted to float. */
17368 full_argvec,
17370 (explain_p
17371 ? tf_warning_or_error
17378 /* Deduce arguments T, i from TT<T> or TT<i>.
17379 We check each element of PARMVEC and ARGVEC individually
17380 rather than the whole TREE_VEC since they can have
17381 different number of elements. */
17388 /* Check if the parameters end in a pack, making them
17389 variadic. */
17395 /* If the template argument list of P contains a pack
17396 expansion that is not the last template argument, the
17397 entire template argument list is a non-deduced
17398 context. */
17407 {
17412 }
17417 DEDUCE_EXACT,
17420 }
17423 /* Fall through to deduce template name. */
17424 }
17428 {
17429 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
17431 /* Simple cases: Value already set, does match or doesn't. */
17436 }
17437 else
17438 {
17439 /* If PARM is `const T' and ARG is only `int', we don't have
17440 a match unless we are allowing additional qualification.
17441 If ARG is `const int' and PARM is just `T' that's OK;
17442 that binds `const int' to `T'. */
17447 /* Consider the case where ARG is `const volatile int' and
17448 PARM is `const T'. Then, T should be `volatile int'. */
17449 arg = cp_build_qualified_type_real
17454 /* Simple cases: Value already set, does match or doesn't. */
17460 /* Make sure that ARG is not a variable-sized array. (Note
17461 that were talking about variable-sized arrays (like
17462 `int[n]'), rather than arrays of unknown size (like
17463 `int[]').) We'll get very confused by such a type since
17464 the bound of the array is not constant, and therefore
17465 not mangleable. Besides, such types are not allowed in
17466 ISO C++, so we can do as we please here. We do allow
17467 them for 'auto' deduction, since that isn't ABI-exposed. */
17471 /* Strip typedefs as in convert_template_argument. */
17473 }
17475 /* If ARG is a parameter pack or an expansion, we cannot unify
17476 against it unless PARM is also a parameter pack. */
17481 /* If the argument deduction results is a METHOD_TYPE,
17482 then there is a problem.
17483 METHOD_TYPE doesn't map to any real C++ type the result of
17484 the deduction can not be of that type. */
17498 {
17499 /* The PARM is not one we're trying to unify. Just check
17500 to see if it matches ARG. */
17506 }
17512 {
17517 }
17519 /* [temp.deduct.type] If, in the declaration of a function template
17520 with a non-type template-parameter, the non-type
17521 template-parameter is used in an expression in the function
17522 parameter-list and, if the corresponding template-argument is
17523 deduced, the template-argument type shall match the type of the
17524 template-parameter exactly, except that a template-argument
17525 deduced from an array bound may be of any integral type.
17526 The non-type parameter might use already deduced type parameters. */
17529 /* Template-parameter dependent expression. Just accept it for now.
17530 It will later be processed in convert_template_argument. */
17531 ;
17536 /* Convert the ARG to the type of PARM; the deduced non-type
17537 template argument must exactly match the types of the
17538 corresponding parameter. */
17541 /* We haven't deduced the type of this parameter yet. Try again
17542 later. */
17544 else
17547 /* If ARG is a parameter pack or an expansion, we cannot unify
17548 against it unless PARM is also a parameter pack. */
17558 {
17559 /* A pointer-to-member constant can be unified only with
17560 another constant. */
17564 /* Just unify the class member. It would be useless (and possibly
17565 wrong, depending on the strict flags) to unify also
17566 PTRMEM_CST_CLASS, because we want to be sure that both parm and
17567 arg refer to the same variable, even if through different
17568 classes. For instance:
17570 struct A { int x; };
17571 struct B : A { };
17573 Unification of &A::x and &B::x must succeed. */
17576 }
17579 {
17583 /* [temp.deduct.call]
17585 A can be another pointer or pointer to member type that can
17586 be converted to the deduced A via a qualification
17587 conversion (_conv.qual_).
17589 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
17590 This will allow for additional cv-qualification of the
17591 pointed-to types if appropriate. */
17594 /* The derived-to-base conversion only persists through one
17595 level of pointers. */
17600 }
17632 /* We have already checked cv-qualification at the top of the
17633 function. */
17637 /* As far as unification is concerned, this wins. Later checks
17638 will invalidate it if necessary. */
17641 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
17642 /* Type INTEGER_CST can come from ordinary constant template args. */
17654 {
17664 /* Check for pack expansions in the parameters. */
17666 {
17668 {
17670 /* We can unify against something with a trailing
17671 parameter pack. */
17673 else
17674 /* [temp.deduct.type]/9: If the template argument list of
17675 P contains a pack expansion that is not the last
17676 template argument, the entire template argument list
17677 is a non-deduced context. */
17679 }
17680 }
17682 /* If we don't have enough arguments to satisfy the parameters
17683 (not counting the pack expression at the end), or we have
17684 too many arguments for a parameter list that doesn't end in
17685 a pack expression, we can't unify. */
17691 /* Unify all of the parameters that precede the (optional)
17692 pack expression. */
17694 {
17699 }
17702 DEDUCE_EXACT,
17705 }
17713 {
17721 }
17724 {
17728 {
17729 /* First, we try to unify the PARM and ARG directly. */
17734 {
17735 /* Fallback to the special case allowed in
17736 [temp.deduct.call]:
17738 If P is a class, and P has the form
17739 template-id, then A can be a derived class of
17740 the deduced A. Likewise, if P is a pointer to
17741 a class of the form template-id, A can be a
17742 pointer to a derived class pointed to by the
17743 deduced A. */
17750 }
17751 }
17755 /* Perhaps PARM is something like S<U> and ARG is S<int>.
17756 Then, we should unify `int' and `U'. */
17758 else
17759 /* There's no chance of unification succeeding. */
17764 }
17771 {
17774 tree a;
17780 /* CV qualifications for methods can never be deduced, they must
17781 match exactly. We need to check them explicitly here,
17782 because type_unification_real treats them as any other
17783 cv-qualified parameter. */
17785 && (!check_cv_quals_for_unify
17805 }
17808 /* Unify a pointer to member with a pointer to member function, which
17809 deduces the type of the member as a function type. */
17811 {
17812 /* Check top-level cv qualifiers */
17820 /* Determine the type of the function we are unifying against. */
17824 }
17843 /* Matched cases are handled by the ARG == PARM test above. */
17847 /* A non-type template parameter that is a variable should be a
17848 an integral constant, in which case, it whould have been
17849 folded into its (constant) value. So we should not be getting
17850 a variable here. */
17861 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
17862 or UNDERLYING_TYPE nodes. */
17866 /* Unification fails if we hit an error node. */
17870 /* An unresolved overload is a nondeduced context. */
17875 /* We must be looking at an expression. This can happen with
17876 something like:
17878 template <int I>
17879 void foo(S<I>, S<I + 2>);
17881 This is a "nondeduced context":
17883 [deduct.type]
17885 The nondeduced contexts are:
17887 --A type that is a template-id in which one or more of
17888 the template-arguments is an expression that references
17889 a template-parameter.
17891 In these cases, we assume deduction succeeded, but don't
17892 actually infer any unifications. */
17897 else
17899 }
17900 }
17901 #undef RECUR_AND_CHECK_FAILURE
17902 \f
17903 /* Note that DECL can be defined in this translation unit, if
17904 required. */
17906 static void
17908 {
17909 tree clone;
17913 }
17915 /* Called if RESULT is explicitly instantiated, or is a member of an
17916 explicitly instantiated class. */
17918 void
17920 {
17923 /* If this entity has already been written out, it's too late to
17924 make any modifications. */
17928 /* For anonymous namespace we don't need to do anything. */
17930 {
17933 }
17936 /* The TREE_PUBLIC flag for function declarations will have been
17937 set correctly by tsubst. */
17940 /* This might have been set by an earlier implicit instantiation. */
17945 else
17946 {
17948 /* Always make artificials weak. */
17951 /* For WIN32 we also want to put explicit instantiations in
17952 linkonce sections. */
17955 }
17957 /* If EXTERN_P, then this function will not be emitted -- unless
17958 followed by an explicit instantiation, at which point its linkage
17959 will be adjusted. If !EXTERN_P, then this function will be
17960 emitted here. In neither circumstance do we want
17961 import_export_decl to adjust the linkage. */
17963 }
17965 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
17966 important template arguments. If any are missing, we check whether
17967 they're important by using error_mark_node for substituting into any
17968 args that were used for partial ordering (the ones between ARGS and END)
17969 and seeing if it bubbles up. */
17971 static bool
17973 {
17978 {
17981 }
17983 {
17987 }
17989 }
17991 /* Given two function templates PAT1 and PAT2, return:
17993 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
17994 -1 if PAT2 is more specialized than PAT1.
17995 0 if neither is more specialized.
17997 LEN indicates the number of parameters we should consider
17998 (defaulted parameters should not be considered).
18000 The 1998 std underspecified function template partial ordering, and
18001 DR214 addresses the issue. We take pairs of arguments, one from
18002 each of the templates, and deduce them against each other. One of
18003 the templates will be more specialized if all the *other*
18004 template's arguments deduce against its arguments and at least one
18005 of its arguments *does* *not* deduce against the other template's
18006 corresponding argument. Deduction is done as for class templates.
18007 The arguments used in deduction have reference and top level cv
18008 qualifiers removed. Iff both arguments were originally reference
18009 types *and* deduction succeeds in both directions, an lvalue reference
18010 wins against an rvalue reference and otherwise the template
18011 with the more cv-qualified argument wins for that pairing (if
18012 neither is more cv-qualified, they both are equal). Unlike regular
18013 deduction, after all the arguments have been deduced in this way,
18014 we do *not* verify the deduced template argument values can be
18015 substituted into non-deduced contexts.
18017 The logic can be a bit confusing here, because we look at deduce1 and
18018 targs1 to see if pat2 is at least as specialized, and vice versa; if we
18019 can find template arguments for pat1 to make arg1 look like arg2, that
18020 means that arg2 is at least as specialized as arg1. */
18022 int
18024 {
18037 /* Remove the this parameter from non-static member functions. If
18038 one is a non-static member function and the other is not a static
18039 member function, remove the first parameter from that function
18040 also. This situation occurs for operator functions where we
18041 locate both a member function (with this pointer) and non-member
18042 operator (with explicit first operand). */
18044 {
18049 }
18051 {
18054 {
18055 len--;
18057 }
18058 }
18060 /* If only one is a conversion operator, they are unordered. */
18064 /* Consider the return type for a conversion function */
18066 {
18069 len++;
18070 }
18072 processing_template_decl++;
18078 /* Stop when an ellipsis is seen. */
18080 {
18091 {
18092 /* When both arguments are pack expansions, we need only
18093 unify the patterns themselves. */
18097 /* This is the last comparison we need to do. */
18099 }
18102 {
18106 }
18109 {
18113 }
18119 {
18125 /* Setup the parameter vector, which contains only ARG1. */
18128 /* Setup the argument vector, which contains the remaining
18129 arguments. */
18138 /* We cannot deduce in the other direction, because ARG1 is
18139 a pack expansion but ARG2 is not. */
18141 }
18143 {
18149 /* Setup the parameter vector, which contains only ARG1. */
18152 /* Setup the argument vector, which contains the remaining
18153 arguments. */
18162 /* We cannot deduce in the other direction, because ARG2 is
18163 a pack expansion but ARG1 is not.*/
18165 }
18167 else
18168 {
18169 /* The normal case, where neither argument is a pack
18170 expansion. */
18177 }
18179 /* If we couldn't deduce arguments for tparms1 to make arg1 match
18180 arg2, then arg2 is not as specialized as arg1. */
18186 /* "If, for a given type, deduction succeeds in both directions
18187 (i.e., the types are identical after the transformations above)
18188 and both P and A were reference types (before being replaced with
18189 the type referred to above):
18190 - if the type from the argument template was an lvalue reference and
18191 the type from the parameter template was not, the argument type is
18192 considered to be more specialized than the other; otherwise,
18193 - if the type from the argument template is more cv-qualified
18194 than the type from the parameter template (as described above),
18195 the argument type is considered to be more specialized than the other;
18196 otherwise,
18197 - neither type is more specialized than the other." */
18200 {
18202 {
18205 else
18207 }
18209 {
18214 }
18215 }
18218 /* We've failed to deduce something in either direction.
18219 These must be unordered. */
18224 /* We have already processed all of the arguments in our
18225 handing of the pack expansion type. */
18230 }
18232 /* "In most cases, all template parameters must have values in order for
18233 deduction to succeed, but for partial ordering purposes a template
18234 parameter may remain without a value provided it is not used in the
18235 types being used for partial ordering."
18237 Thus, if we are missing any of the targs1 we need to substitute into
18238 origs1, then pat2 is not as specialized as pat1. This can happen when
18239 there is a nondeduced context. */
18245 processing_template_decl--;
18247 /* All things being equal, if the next argument is a pack expansion
18248 for one function but not for the other, prefer the
18249 non-variadic function. FIXME this is bogus; see c++/41958. */
18253 {
18256 }
18262 else
18264 }
18266 /* Determine which of two partial specializations of TMPL is more
18267 specialized.
18269 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
18270 to the first partial specialization. The TREE_VALUE is the
18271 innermost set of template parameters for the partial
18272 specialization. PAT2 is similar, but for the second template.
18274 Return 1 if the first partial specialization is more specialized;
18275 -1 if the second is more specialized; 0 if neither is more
18276 specialized.
18278 See [temp.class.order] for information about determining which of
18279 two templates is more specialized. */
18281 static int
18283 {
18284 tree targs;
18292 /* Just like what happens for functions, if we are ordering between
18293 different class template specializations, we may encounter dependent
18294 types in the arguments, and we need our dependency check functions
18295 to behave correctly. */
18301 {
18304 }
18310 {
18313 }
18316 /* In the case of a tie where at least one of the class templates
18317 has a parameter pack at the end, the template with the most
18318 non-packed parameters wins. */
18320 && any_deductions
18323 {
18329 /* We don't count the pack expansion at the end. */
18339 }
18342 }
18344 /* Return the template arguments that will produce the function signature
18345 DECL from the function template FN, with the explicit template
18346 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
18347 also match. Return NULL_TREE if no satisfactory arguments could be
18348 found. */
18350 static tree
18352 {
18356 tree decl_arg_types;
18359 tree arg;
18363 /* Never do unification on the 'this' parameter. */
18384 }
18386 /* Return the innermost template arguments that, when applied to a partial
18387 specialization of TMPL whose innermost template parameters are
18388 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
18389 ARGS.
18391 For example, suppose we have:
18393 template <class T, class U> struct S {};
18394 template <class T> struct S<T*, int> {};
18396 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
18397 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
18398 int}. The resulting vector will be {double}, indicating that `T'
18399 is bound to `double'. */
18401 static tree
18403 {
18405 tree deduced_args;
18406 tree innermost_deduced_args;
18410 {
18414 innermost_deduced_args);
18415 }
18416 else
18429 /* Verify that nondeduced template arguments agree with the type
18430 obtained from argument deduction.
18432 For example:
18434 struct A { typedef int X; };
18435 template <class T, class U> struct C {};
18436 template <class T> struct C<T, typename T::X> {};
18438 Then with the instantiation `C<A, int>', we can deduce that
18439 `T' is `A' but unify () does not check whether `typename T::X'
18440 is `int'. */
18446 /* We only need to check the innermost arguments; the other
18447 arguments will always agree. */
18452 /* Now that we have bindings for all of the template arguments,
18453 ensure that the arguments deduced for the template template
18454 parameters have compatible template parameter lists. See the use
18455 of template_template_parm_bindings_ok_p in fn_type_unification
18456 for more information. */
18461 }
18463 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
18464 Return the TREE_LIST node with the most specialized template, if
18465 any. If there is no most specialized template, the error_mark_node
18466 is returned.
18468 Note that this function does not look at, or modify, the
18469 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
18470 returned is one of the elements of INSTANTIATIONS, callers may
18471 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
18472 and retrieve it from the value returned. */
18474 tree
18476 {
18483 {
18489 fate--;
18494 fate++;
18499 {
18500 /* Equally specialized, move to next function. If there
18501 is no next function, nothing's most specialized. */
18506 }
18507 }
18510 /* Now verify that champ is better than everything earlier in the
18511 instantiation list. */
18519 {
18522 }
18524 processing_template_decl--;
18530 }
18532 /* If DECL is a specialization of some template, return the most
18533 general such template. Otherwise, returns NULL_TREE.
18535 For example, given:
18537 template <class T> struct S { template <class U> void f(U); };
18539 if TMPL is `template <class U> void S<int>::f(U)' this will return
18540 the full template. This function will not trace past partial
18541 specializations, however. For example, given in addition:
18543 template <class T> struct S<T*> { template <class U> void f(U); };
18545 if TMPL is `template <class U> void S<int*>::f(U)' this will return
18546 `template <class T> template <class U> S<T*>::f(U)'. */
18548 tree
18550 {
18551 /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is
18552 an immediate specialization. */
18554 {
18558 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a
18559 template friend. */
18564 }
18566 /* Look for more and more general templates. */
18568 {
18569 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
18570 (See cp-tree.h for details.) */
18578 /* Stop if we run into an explicitly specialized class template. */
18585 }
18588 }
18590 /* Return the most specialized of the class template partial
18591 specializations which can produce TYPE, a specialization of some class
18592 template. The value returned is actually a TREE_LIST; the TREE_TYPE is
18593 a _TYPE node corresponding to the partial specialization, while the
18594 TREE_PURPOSE is the set of template arguments that must be
18595 substituted into the TREE_TYPE in order to generate TYPE.
18597 If the choice of partial specialization is ambiguous, a diagnostic
18598 is issued, and the error_mark_node is returned. If there are no
18599 partial specializations matching TYPE, then NULL_TREE is
18600 returned, indicating that the primary template should be used. */
18602 static tree
18604 {
18606 tree t;
18607 tree champ;
18616 /* For determining which partial specialization to use, only the
18617 innermost args are interesting. */
18619 {
18622 }
18625 {
18626 tree partial_spec_args;
18627 tree spec_args;
18636 {
18637 /* Discard the outer levels of args, and then substitute in the
18638 template args from the enclosing class. */
18640 partial_spec_args = tsubst_template_args
18643 /* And the same for the partial specialization TEMPLATE_DECL. */
18645 }
18647 partial_spec_args =
18649 partial_spec_args,
18663 partial_spec_args,
18664 args);
18666 {
18671 }
18672 }
18682 {
18685 ;
18686 else
18687 {
18689 {
18692 {
18695 }
18696 }
18698 }
18699 }
18703 {
18706 {
18709 }
18710 }
18713 {
18721 {
18724 }
18727 }
18730 }
18732 /* Explicitly instantiate DECL. */
18734 void
18736 {
18741 /* An error occurred, for which grokdeclarator has already issued
18742 an appropriate message. */
18745 {
18748 }
18750 {
18751 /* There is an asymmetry here in the way VAR_DECLs and
18752 FUNCTION_DECLs are handled by grokdeclarator. In the case of
18753 the latter, the DECL we get back will be marked as a
18754 template instantiation, and the appropriate
18755 DECL_TEMPLATE_INFO will be set up. This does not happen for
18756 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
18757 should handle VAR_DECLs as it currently handles
18758 FUNCTION_DECLs. */
18760 {
18763 }
18766 {
18769 }
18771 {
18776 }
18777 }
18779 {
18782 }
18783 else
18786 /* Check for various error cases. Note that if the explicit
18787 instantiation is valid the RESULT will currently be marked as an
18788 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
18789 until we get here. */
18792 {
18793 /* DR 259 [temp.spec].
18795 Both an explicit instantiation and a declaration of an explicit
18796 specialization shall not appear in a program unless the explicit
18797 instantiation follows a declaration of the explicit specialization.
18799 For a given set of template parameters, if an explicit
18800 instantiation of a template appears after a declaration of an
18801 explicit specialization for that template, the explicit
18802 instantiation has no effect. */
18804 }
18806 {
18807 /* [temp.spec]
18809 No program shall explicitly instantiate any template more
18810 than once.
18812 We check DECL_NOT_REALLY_EXTERN so as not to complain when
18813 the first instantiation was `extern' and the second is not,
18814 and EXTERN_P for the opposite case. */
18817 /* If an "extern" explicit instantiation follows an ordinary
18818 explicit instantiation, the template is instantiated. */
18821 }
18823 {
18826 }
18828 {
18831 }
18834 ;
18836 {
18839 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
18842 }
18843 else
18851 }
18853 static void
18855 {
18861 {
18864 }
18865 }
18867 /* Called from do_type_instantiation through binding_table_foreach to
18868 do recursive instantiation for the type bound in ENTRY. */
18869 static void
18871 {
18877 }
18879 /* Called from do_type_instantiation to instantiate a member
18880 (a member function or a static member variable) of an
18881 explicitly instantiated class template. */
18882 static void
18884 {
18889 }
18891 /* Perform an explicit instantiation of template class T. STORAGE, if
18892 non-null, is the RID for extern, inline or static. COMPLAIN is
18893 nonzero if this is called from the parser, zero if called recursively,
18894 since the standard is unclear (as detailed below). */
18896 void
18898 {
18908 {
18909 tree tmpl =
18913 else
18916 }
18921 {
18924 t);
18926 }
18929 {
18931 {
18933 {
18936 "ISO C++ 1998 forbids the use of %<extern%> on "
18938 }
18939 else
18941 "ISO C++ forbids the use of %qE"
18943 }
18951 else
18952 {
18954 storage);
18956 }
18957 }
18960 {
18961 /* DR 259 [temp.spec].
18963 Both an explicit instantiation and a declaration of an explicit
18964 specialization shall not appear in a program unless the explicit
18965 instantiation follows a declaration of the explicit specialization.
18967 For a given set of template parameters, if an explicit
18968 instantiation of a template appears after a declaration of an
18969 explicit specialization for that template, the explicit
18970 instantiation has no effect. */
18972 }
18974 {
18975 /* [temp.spec]
18977 No program shall explicitly instantiate any template more
18978 than once.
18980 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
18981 instantiation was `extern'. If EXTERN_P then the second is.
18982 These cases are OK. */
18989 /* If we've already instantiated the template, just return now. */
18992 }
19000 {
19001 tree tmp;
19003 /* In contrast to implicit instantiation, where only the
19004 declarations, and not the definitions, of members are
19005 instantiated, we have here:
19007 [temp.explicit]
19009 The explicit instantiation of a class template specialization
19010 implies the instantiation of all of its members not
19011 previously explicitly specialized in the translation unit
19012 containing the explicit instantiation.
19014 Of course, we can't instantiate member template classes, since
19015 we don't have any arguments for them. Note that the standard
19016 is unclear on whether the instantiation of the members are
19017 *explicit* instantiations or not. However, the most natural
19018 interpretation is that it should be an explicit instantiation. */
19033 }
19034 }
19036 /* Given a function DECL, which is a specialization of TMPL, modify
19037 DECL to be a re-instantiation of TMPL with the same template
19038 arguments. TMPL should be the template into which tsubst'ing
19039 should occur for DECL, not the most general template.
19041 One reason for doing this is a scenario like this:
19043 template <class T>
19044 void f(const T&, int i);
19046 void g() { f(3, 7); }
19048 template <class T>
19049 void f(const T& t, const int i) { }
19051 Note that when the template is first instantiated, with
19052 instantiate_template, the resulting DECL will have no name for the
19053 first parameter, and the wrong type for the second. So, when we go
19054 to instantiate the DECL, we regenerate it. */
19056 static void
19058 {
19059 /* The arguments used to instantiate DECL, from the most general
19060 template. */
19061 tree args;
19062 tree code_pattern;
19067 /* Make sure that we can see identifiers, and compute access
19068 correctly. */
19072 {
19073 tree decl_parm;
19074 tree pattern_parm;
19075 tree specs;
19089 specs);
19091 /* Merge parameter declarations. */
19094 pattern_parm
19098 {
19099 tree parm_type;
19100 tree attributes;
19105 NULL_TREE);
19111 {
19114 }
19117 }
19118 /* Merge any parameters that match with the function parameter
19119 pack. */
19121 {
19123 tree expanded_types;
19124 /* Expand the TYPE_PACK_EXPANSION that provides the types for
19125 the parameters in this function parameter pack. */
19130 {
19131 tree parm_type;
19132 tree attributes;
19135 /* Rename the parameter to include the index. */
19144 {
19147 }
19149 }
19150 }
19151 /* Merge additional specifiers from the CODE_PATTERN. */
19155 }
19157 {
19165 }
19166 else
19170 }
19172 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
19173 substituted to get DECL. */
19175 tree
19177 {
19180 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
19181 for the instantiation. This is not always the most general
19182 template. Consider, for example:
19184 template <class T>
19185 struct S { template <class U> void f();
19186 template <> void f<int>(); };
19188 and an instantiation of S<double>::f<int>. We want TD to be the
19189 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
19191 more general template. */
19193 /* We must also deal with friend templates. Given:
19195 template <class T> struct S {
19196 template <class U> friend void f() {};
19197 };
19199 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
19200 so far as the language is concerned, but that's still
19201 where we get the pattern for the instantiation from. On
19202 other hand, if the definition comes outside the class, say:
19204 template <class T> struct S {
19205 template <class U> friend void f();
19206 };
19207 template <class U> friend void f() {}
19209 we don't need to look any further. That's what the check for
19210 DECL_INITIAL is for. */
19214 {
19215 /* The present template, TD, should not be a definition. If it
19216 were a definition, we should be using it! Note that we
19217 cannot restructure the loop to just keep going until we find
19218 a template with a definition, since that might go too far if
19219 a specialization was declared, but not defined. */
19223 /* Fetch the more general template. */
19225 }
19228 }
19230 /* Returns true if we need to instantiate this template instance even if we
19231 know we aren't going to emit it.. */
19233 bool
19235 {
19236 /* We always instantiate inline functions so that we can inline them. An
19237 explicit instantiation declaration prohibits implicit instantiation of
19238 non-inline functions. With high levels of optimization, we would
19239 normally inline non-inline functions -- but we're not allowed to do
19240 that for "extern template" functions. Therefore, we check
19241 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
19245 /* And we need to instantiate static data members so that
19246 their initializers are available in integral constant
19247 expressions. */
19250 }
19252 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
19253 instantiate it now, modifying TREE_TYPE (fn). */
19255 void
19257 {
19271 {
19273 {
19288 }
19289 else
19291 }
19292 else
19293 {
19294 /* This is an implicitly declared function, so NOEX is a list of
19295 other functions to evaluate and merge. */
19296 tree elt;
19299 {
19301 tree subspec;
19305 }
19306 }
19311 {
19314 else
19316 }
19317 }
19319 /* Produce the definition of D, a _DECL generated from a template. If
19320 DEFER_OK is nonzero, then we don't have to actually do the
19321 instantiation now; we just have to do it sometime. Normally it is
19322 an error if this is an explicit instantiation but D is undefined.
19323 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
19324 explicitly instantiated class template. */
19326 tree
19329 {
19331 tree gen_args;
19332 tree args;
19333 tree td;
19334 tree code_pattern;
19335 tree spec;
19336 tree gen_tmpl;
19342 tree fn_context;
19345 /* This function should only be used to instantiate templates for
19346 functions and static member variables. */
19349 /* Variables are never deferred; if instantiation is required, they
19350 are instantiated right away. That allows for better code in the
19351 case that an expression refers to the value of the variable --
19352 if the variable has a constant value the referring expression can
19353 take advantage of that fact. */
19358 /* Don't instantiate cloned functions. Instead, instantiate the
19359 functions they cloned. */
19367 /* D has already been instantiated or explicitly specialized, so
19368 there's nothing for us to do here.
19370 It might seem reasonable to check whether or not D is an explicit
19371 instantiation, and, if so, stop here. But when an explicit
19372 instantiation is deferred until the end of the compilation,
19373 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
19374 the instantiation. */
19377 /* Check to see whether we know that this template will be
19378 instantiated in some other file, as with "extern template"
19379 extension. */
19382 /* In general, we do not instantiate such templates. */
19390 /* We should already have the extra args. */
19393 /* And what's in the hash table should match D. */
19397 /* This needs to happen before any tsubsting. */
19403 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
19404 for the instantiation. */
19408 /* We should never be trying to instantiate a member of a class
19409 template or partial specialization. */
19414 /* In the case of a friend template whose definition is provided
19415 outside the class, we may have too many arguments. Drop the
19416 ones we don't need. The same is true for specializations. */
19417 args = get_innermost_template_args
19419 else
19425 else
19428 /* We may be in the middle of deferred access check. Disable it now. */
19431 /* Unless an explicit instantiation directive has already determined
19432 the linkage of D, remember that a definition is available for
19433 this entity. */
19443 /* If D is a member of an explicitly instantiated class template,
19444 and no definition is available, treat it like an implicit
19445 instantiation. */
19448 {
19449 /* Leave linkage flags alone on instantiations with anonymous
19450 visibility. */
19452 {
19455 }
19457 }
19462 /* Defer all other templates, unless we have been explicitly
19463 forbidden from doing so. */
19465 template. */
19466 ! pattern_defined
19467 /* If it's OK to postpone instantiation, do so. */
19468 || defer_ok
19469 /* If this is a static data member that will be defined
19470 elsewhere, we don't want to instantiate the entire data
19471 member, but we do want to instantiate the initializer so that
19472 we can substitute that elsewhere. */
19474 {
19475 /* The definition of the static data member is now required so
19476 we must substitute the initializer. */
19480 {
19481 tree ns;
19482 tree init;
19489 args,
19492 /* Make sure the initializer is still constant, in case of
19493 circular dependency (template/instantiate6.C). */
19494 const_init
19498 LOOKUP_ONLYCONVERTING);
19501 }
19503 /* We restore the source position here because it's used by
19504 add_pending_template. */
19510 /* [temp.explicit]
19512 The definition of a non-exported function template, a
19513 non-exported member function template, or a non-exported
19514 member function or static data member of a class template
19515 shall be present in every translation unit in which it is
19516 explicitly instantiated. */
19520 /* If we're in unevaluated context, we just wanted to get the
19521 constant value; this isn't an odr use, so don't queue
19522 a full instantiation. */
19525 /* ??? Historically, we have instantiated inline functions, even
19526 when marked as "extern template". */
19530 }
19531 /* Tell the repository that D is available in this translation unit
19532 -- and see if it is supposed to be instantiated here. */
19534 {
19535 /* In a PCH file, despite the fact that the repository hasn't
19536 requested instantiation in the PCH it is still possible that
19537 an instantiation will be required in a file that includes the
19538 PCH. */
19541 /* Instantiate inline functions so that the inliner can do its
19542 job, even though we'll not be emitting a copy of this
19543 function. */
19546 }
19552 else
19553 {
19558 }
19560 /* Mark D as instantiated so that recursive calls to
19561 instantiate_decl do not try to instantiate it again. */
19564 /* Regenerate the declaration in case the template has been modified
19565 by a subsequent redeclaration. */
19568 /* We already set the file and line above. Reset them now in case
19569 they changed as a result of calling regenerate_decl_from_template. */
19573 {
19574 tree init;
19577 /* Clear out DECL_RTL; whatever was there before may not be right
19578 since we've reset the type of the declaration. */
19582 /* The initializer is placed in DECL_INITIAL by
19583 regenerate_decl_from_template so we don't need to
19584 push/pop_access_scope again here. Pull it out so that
19585 cp_finish_decl can process it. */
19590 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
19591 initializer. That function will defer actual emission until
19592 we have a chance to determine linkage. */
19595 /* Enter the scope of D so that access-checking works correctly. */
19600 }
19604 {
19606 tree subst_decl;
19607 tree tmpl_parm;
19608 tree spec_parm;
19611 /* Save away the current list, in case we are instantiating one
19612 template from within the body of another. */
19615 /* Set up the list of local specializations. */
19618 /* Set up context. */
19622 else
19625 /* Some typedefs referenced from within the template code need to be
19626 access checked at template instantiation time, i.e now. These
19627 types were added to the template at parsing time. Let's get those
19628 and perform the access checks then. */
19630 gen_args);
19632 /* Create substitution entries for the parameters. */
19637 {
19641 }
19643 {
19645 {
19648 }
19649 else
19650 {
19651 /* Register the (value) argument pack as a specialization of
19652 TMPL_PARM, then move on. */
19655 }
19656 }
19659 /* Substitute into the body of the function. */
19663 else
19664 {
19669 /* Set the current input_location to the end of the function
19670 so that finish_function knows where we are. */
19671 input_location
19673 }
19675 /* We don't need the local specializations any more. */
19679 /* Finish the function. */
19683 else
19684 {
19687 }
19691 }
19693 /* We're not deferring instantiation any more. */
19701 out:
19711 }
19713 /* Run through the list of templates that we wish we could
19714 instantiate, and instantiate any we can. RETRIES is the
19715 number of times we retry pending template instantiation. */
19717 void
19719 {
19723 /* Instantiating templates may trigger vtable generation. This in turn
19724 may require further template instantiations. We place a limit here
19725 to avoid infinite loop. */
19727 {
19731 " instantiating %q+D, possibly from virtual table generation"
19735 /* Pretend that we defined it. */
19738 }
19740 do
19741 {
19746 {
19751 {
19752 tree fn;
19755 {
19759 fn;
19767 }
19770 }
19771 else
19772 {
19775 {
19776 instantiation
19782 }
19786 }
19789 /* If INSTANTIATION has been instantiated, then we don't
19790 need to consider it again in the future. */
19792 else
19793 {
19796 }
19799 }
19801 }
19805 }
19807 /* Substitute ARGVEC into T, which is a list of initializers for
19808 either base class or a non-static data member. The TREE_PURPOSEs
19809 are DECLs, and the TREE_VALUEs are the initializer values. Used by
19810 instantiate_decl. */
19812 static tree
19814 {
19818 {
19819 tree decl;
19820 tree init;
19826 {
19827 tree expr;
19828 tree arg;
19830 /* Expand the base class expansion type into separate base
19831 classes. */
19833 tf_warning_or_error,
19834 NULL_TREE);
19838 /* We'll be building separate TREE_LISTs of arguments for
19839 each base. */
19845 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
19846 expand each argument in the TREE_VALUE of t. */
19853 /* VOID_TYPE_NODE is used to indicate
19854 value-initialization. */
19855 {
19858 }
19859 else
19860 {
19861 /* Substitute parameter packs into each argument in the
19862 TREE_LIST. */
19865 {
19866 tree expanded_exprs;
19868 /* Expand the argument. */
19870 expanded_exprs
19872 tf_warning_or_error,
19873 NULL_TREE);
19877 /* Prepend each of the expanded expressions to the
19878 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
19880 {
19885 }
19886 }
19889 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
19890 since we built them backwards. */
19892 {
19895 }
19896 }
19897 }
19900 {
19902 {
19906 }
19907 else
19908 {
19909 tree tmp;
19924 /* If we had an initializer but it instantiated to nothing,
19925 value-initialize the object. This will only occur when
19926 the initializer was a pack expansion where the parameter
19927 packs used in that expansion were of length zero. */
19930 }
19933 {
19937 }
19938 }
19939 }
19941 }
19943 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
19945 static void
19947 {
19952 else
19954 }
19956 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
19957 is the instantiation (which should have been created with
19958 start_enum) and ARGS are the template arguments to use. */
19960 static void
19962 {
19963 tree e;
19969 {
19970 tree value;
19971 tree decl;
19974 /* Note that in a template enum, the TREE_VALUE is the
19975 CONST_DECL, not the corresponding INTEGER_CST. */
19980 /* Give this enumeration constant the correct access. */
19983 /* Actually build the enumerator itself. */
19984 build_enumerator
19986 }
19996 }
19998 /* DECL is a FUNCTION_DECL that is a template specialization. Return
19999 its type -- but without substituting the innermost set of template
20000 arguments. So, innermost set of template parameters will appear in
20001 the type. */
20003 tree
20005 {
20006 tree fn_type;
20007 tree tmpl;
20008 tree targs;
20009 tree tparms;
20017 /* There should be as many levels of arguments as there are levels
20018 of parameters. */
20024 /* No substitution is necessary. */
20025 ;
20026 else
20027 {
20029 tree partial_args;
20031 /* Replace the innermost level of the TARGS with NULL_TREEs to
20032 let tsubst know not to substitute for those parameters. */
20041 /* Make sure that we can see identifiers, and compute access
20042 correctly. */
20046 /* Now, do the (partial) substitution to figure out the
20047 appropriate function type. */
20051 /* Substitute into the template parameters to obtain the real
20052 innermost set of parameters. This step is important if the
20053 innermost set of template parameters contains value
20054 parameters whose types depend on outer template parameters. */
20059 }
20062 }
20064 /* Return truthvalue if we're processing a template different from
20065 the last one involved in diagnostics. */
20066 int
20068 {
20070 }
20072 /* Remember current template involved in diagnostics. */
20073 void
20075 {
20077 }
20081 {
20083 }
20085 /* [temp.param] Check that template non-type parm TYPE is of an allowable
20086 type. Return zero for ok, nonzero for disallowed. Issue error and
20087 warning messages under control of COMPLAIN. */
20089 static int
20091 {
20108 {
20111 else
20113 type);
20114 }
20116 }
20118 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
20119 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
20121 static bool
20123 {
20124 tree scope;
20126 /* [temp.dep.type]
20128 A type is dependent if it is:
20130 -- a template parameter. Template template parameters are types
20131 for us (since TYPE_P holds true for them) so we handle
20132 them here. */
20136 /* -- a qualified-id with a nested-name-specifier which contains a
20137 class-name that names a dependent type or whose unqualified-id
20138 names a dependent type. */
20141 /* -- a cv-qualified type where the cv-unqualified type is
20142 dependent. */
20144 /* -- a compound type constructed from any dependent type. */
20154 {
20155 tree arg_type;
20160 arg_type;
20165 }
20166 /* -- an array type constructed from any dependent type or whose
20167 size is specified by a constant expression that is
20168 value-dependent.
20170 We checked for type- and value-dependence of the bounds in
20171 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
20173 {
20178 }
20180 /* -- a template-id in which either the template name is a template
20181 parameter ... */
20184 /* ... or any of the template arguments is a dependent type or
20185 an expression that is type-dependent or value-dependent. */
20187 && (any_dependent_template_arguments_p
20191 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
20192 dependent; if the argument of the `typeof' expression is not
20193 type-dependent, then it should already been have resolved. */
20199 /* A template argument pack is dependent if any of its packed
20200 arguments are. */
20202 {
20208 }
20210 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
20211 be template parameters. */
20215 /* The standard does not specifically mention types that are local
20216 to template functions or local classes, but they should be
20217 considered dependent too. For example:
20219 template <int I> void f() {
20220 enum E { a = I };
20221 S<sizeof (E)> s;
20222 }
20224 The size of `E' cannot be known until the value of `I' has been
20225 determined. Therefore, `E' must be considered dependent. */
20229 /* Don't use type_dependent_expression_p here, as it can lead
20230 to infinite recursion trying to determine whether a lambda
20231 nested in a lambda is dependent (c++/47687). */
20235 && (any_dependent_template_arguments_p
20239 /* Other types are non-dependent. */
20241 }
20243 /* Returns TRUE if TYPE is dependent, in the sense of
20244 [temp.dep.type]. Note that a NULL type is considered dependent. */
20246 bool
20248 {
20249 /* If there are no template parameters in scope, then there can't be
20250 any dependent types. */
20252 {
20253 /* If we are not processing a template, then nobody should be
20254 providing us with a dependent type. */
20258 }
20260 /* If the type is NULL, we have not computed a type for the entity
20261 in question; in that case, the type is dependent. */
20265 /* Erroneous types can be considered non-dependent. */
20269 /* If we have not already computed the appropriate value for TYPE,
20270 do so now. */
20272 {
20275 }
20278 }
20280 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
20281 lookup. In other words, a dependent type that is not the current
20282 instantiation. */
20284 bool
20286 {
20289 }
20291 /* T is a SCOPE_REF; return whether we need to consider it
20292 instantiation-dependent so that we can check access at instantiation
20293 time even though we know which member it resolves to. */
20295 static bool
20297 {
20303 else
20305 }
20307 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
20308 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
20309 expression. */
20311 /* Note that this predicate is not appropriate for general expressions;
20312 only constant expressions (that satisfy potential_constant_expression)
20313 can be tested for value dependence. */
20315 bool
20317 {
20321 /* A name declared with a dependent type. */
20326 {
20328 /* A name that has not been looked up -- must be dependent. */
20332 /* A non-type template parm. */
20336 /* A non-type template parm. */
20342 /* A constant with literal type and is initialized
20343 with an expression that is value-dependent.
20345 Note that a non-dependent parenthesized initializer will have
20346 already been replaced with its constant value, so if we see
20347 a TREE_LIST it must be dependent. */
20360 /* These expressions are value-dependent if the type to which
20361 the cast occurs is dependent or the expression being casted
20362 is value-dependent. */
20363 {
20369 /* A functional cast has a list of operands. */
20372 {
20373 /* If there are no operands, it must be an expression such
20374 as "int()". This should not happen for aggregate types
20375 because it would form non-constant expressions. */
20380 }
20386 }
20391 /* FALLTHRU */
20394 /* A `sizeof' expression is value-dependent if the operand is
20395 type-dependent or is a pack expansion. */
20404 /* An 'encode' expression is value-dependent if the operand is
20405 type-dependent. */
20414 /* All instantiation-dependent expressions should also be considered
20415 value-dependent. */
20423 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
20424 is value-dependent. */
20425 {
20434 }
20437 {
20441 }
20452 {
20456 }
20459 {
20466 {
20468 /* In a call to a constexpr member function, look through the
20469 implicit ADDR_EXPR on the object argument so that it doesn't
20470 cause the call to be considered value-dependent. We also
20471 look through it in potential_constant_expression. */
20478 }
20480 }
20483 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
20484 type-dependent. */
20488 {
20490 tree val;
20495 }
20498 /* Treat a GNU statement expression as dependent to avoid crashing
20499 under fold_non_dependent_expr; it can't be constant. */
20503 /* A constant expression is value-dependent if any subexpression is
20504 value-dependent. */
20506 {
20513 {
20517 {
20520 /* In some cases, some of the operands may be missing.l
20521 (For example, in the case of PREDECREMENT_EXPR, the
20522 amount to increment by may be missing.) That doesn't
20523 make the expression dependent. */
20526 }
20527 }
20531 }
20533 }
20535 /* The expression is not value-dependent. */
20537 }
20539 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
20540 [temp.dep.expr]. Note that an expression with no type is
20541 considered dependent. Other parts of the compiler arrange for an
20542 expression with type-dependent subexpressions to have no type, so
20543 this function doesn't have to be fully recursive. */
20545 bool
20547 {
20554 /* An unresolved name is always dependent. */
20558 /* Some expression forms are never type-dependent. */
20571 /* The types of these expressions depends only on the type to which
20572 the cast occurs. */
20581 /* The types of these expressions depends only on the type created
20582 by the expression. */
20585 {
20586 /* For NEW_EXPR tree nodes created inside a template, either
20587 the object type itself or a TREE_LIST may appear as the
20588 operand 1. */
20591 /* This is an array type. We need to check array dimensions
20592 as well. */
20594 || value_dependent_expression_p
20596 else
20598 }
20601 {
20605 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
20606 contains an identifier associated by name lookup with one or more
20607 declarations declared with a dependent type, or...a
20608 nested-name-specifier or qualified-id that names a member of an
20609 unknown specialization. */
20612 }
20617 && (any_dependent_template_arguments_p
20629 {
20630 tree elt;
20634 {
20637 }
20639 }
20641 /* A static data member of the current instantiation with incomplete
20642 array type is type-dependent, as the definition and specializations
20643 can have different bounds. */
20650 /* An array of unknown bound depending on a variadic parameter, eg:
20652 template<typename... Args>
20653 void foo (Args... args)
20654 {
20655 int arr[] = { args... };
20656 }
20658 template<int... vals>
20659 void bar ()
20660 {
20661 int arr[] = { vals... };
20662 }
20664 If the array has no length and has an initializer, it must be that
20665 we couldn't determine its length in cp_complete_array_type because
20666 it is dependent. */
20674 {
20679 {
20685 }
20686 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
20690 /* Always dependent, on the number of arguments if nothing else. */
20698 {
20703 }
20708 {
20712 }
20714 }
20719 }
20721 /* walk_tree callback function for instantiation_dependent_expression_p,
20722 below. Returns non-zero if a dependent subexpression is found. */
20724 static tree
20727 {
20729 {
20730 /* We don't have to worry about decltype currently because decltype
20731 of an instantiation-dependent expr is a dependent type. This
20732 might change depending on the resolution of DR 1172. */
20735 }
20738 {
20739 /* Don't treat an argument list as dependent just because it has no
20740 TREE_TYPE. */
20747 /* A constant with a dependent initializer is dependent. */
20755 /* Handle expressions with type operands. */
20760 {
20765 {
20768 else
20769 {
20772 }
20773 }
20775 }
20787 /* In a template, finish_class_member_access_expr creates a
20788 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
20789 type-dependent, so that we can check access control at
20790 instantiation time (PR 42277). See also Core issue 1273. */
20797 else
20800 /* Treat statement-expressions as dependent. */
20806 }
20810 else
20812 }
20814 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
20815 sense defined by the ABI:
20817 "An expression is instantiation-dependent if it is type-dependent
20818 or value-dependent, or it has a subexpression that is type-dependent
20819 or value-dependent." */
20821 bool
20823 {
20824 tree result;
20835 }
20837 /* Like type_dependent_expression_p, but it also works while not processing
20838 a template definition, i.e. during substitution or mangling. */
20840 bool
20842 {
20848 }
20850 /* Returns TRUE if ARGS contains a type-dependent expression. */
20852 bool
20854 {
20856 tree arg;
20859 {
20862 }
20864 }
20866 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
20867 expressions) contains any type-dependent expressions. */
20869 bool
20871 {
20877 }
20879 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
20880 expressions) contains any value-dependent expressions. */
20882 bool
20884 {
20890 }
20892 /* Returns TRUE if the ARG (a template argument) is dependent. */
20894 bool
20896 {
20900 /* Assume a template argument that was wrongly written by the user
20901 is dependent. This is consistent with what
20902 any_dependent_template_arguments_p [that calls this function]
20903 does. */
20914 {
20918 {
20921 }
20924 }
20927 else
20930 }
20932 /* Returns true if ARGS (a collection of template arguments) contains
20933 any types that require structural equality testing. */
20935 bool
20937 {
20947 {
20950 {
20956 {
20957 /* Look inside the argument pack. */
20960 }
20963 {
20976 }
20977 }
20978 }
20981 }
20983 /* Returns true if ARGS (a collection of template arguments) contains
20984 any dependent arguments. */
20986 bool
20988 {
20998 {
21003 }
21006 }
21008 /* Returns TRUE if the template TMPL is dependent. */
21010 bool
21012 {
21014 {
21016 {
21020 }
21022 }
21024 /* Template template parameters are dependent. */
21028 /* So are names that have not been looked up. */
21031 /* So are member templates of dependent classes. */
21035 }
21037 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
21039 bool
21041 {
21044 }
21046 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
21047 is dependent. */
21049 bool
21051 {
21058 {
21079 {
21083 }
21087 {
21091 {
21096 }
21097 }
21098 }
21101 }
21103 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
21104 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
21105 no such TYPE can be found. Note that this function peers inside
21106 uninstantiated templates and therefore should be used only in
21107 extremely limited situations. ONLY_CURRENT_P restricts this
21108 peering to the currently open classes hierarchy (which is required
21109 when comparing types). */
21111 tree
21113 {
21114 tree scope;
21115 tree name;
21116 tree decl;
21118 tree pushed_scope;
21119 tree result;
21124 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
21125 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
21126 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
21127 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
21128 identifier of the TYPENAME_TYPE anymore.
21129 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
21130 TYPENAME_TYPE instead, we avoid messing up with a possible
21131 typedef variant case. */
21134 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
21135 it first before we can figure out what NAME refers to. */
21137 {
21139 /* Given a class template A with a dependent base with nested type C,
21140 typedef typename A::C::C C will land us here, as trying to resolve
21141 the initial A::C leads to the local C typedef, which leads back to
21142 A::C::C. So we break the recursion now. */
21144 else
21146 }
21147 /* If we don't know what SCOPE refers to, then we cannot resolve the
21148 TYPENAME_TYPE. */
21151 /* If the SCOPE is a template type parameter, we have no way of
21152 resolving the name. */
21155 /* If the SCOPE is not the current instantiation, there's no reason
21156 to look inside it. */
21159 /* If this is a typedef, we don't want to look inside (c++/11987). */
21162 /* If SCOPE isn't the template itself, it will not have a valid
21163 TYPE_FIELDS list. */
21165 /* scope is either the template itself or a compatible instantiation
21166 like X<T>, so look up the name in the original template. */
21168 else
21169 /* scope is a partial instantiation, so we can't do the lookup or we
21170 will lose the template arguments. */
21172 /* Enter the SCOPE so that name lookup will be resolved as if we
21173 were in the class definition. In particular, SCOPE will no
21174 longer be considered a dependent type. */
21176 /* Look up the declaration. */
21178 tf_warning_or_error);
21182 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
21183 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
21188 {
21192 }
21195 {
21196 tree tmpl;
21197 tree args;
21198 /* Obtain the template and the arguments. */
21201 /* Instantiate the template. */
21207 }
21209 /* Leave the SCOPE. */
21213 /* If we failed to resolve it, return the original typename. */
21217 /* If lookup found a typename type, resolve that too. */
21219 {
21220 /* Ill-formed programs can cause infinite recursion here, so we
21221 must catch that. */
21225 }
21227 /* Qualify the resulting type. */
21233 }
21235 /* EXPR is an expression which is not type-dependent. Return a proxy
21236 for EXPR that can be used to compute the types of larger
21237 expressions containing EXPR. */
21239 tree
21241 {
21242 tree inner_expr;
21244 #ifdef ENABLE_CHECKING
21245 /* Try to get a constant value for all non-dependent expressions in
21246 order to expose bugs in *_dependent_expression_p and constexpr. */
21249 #endif
21251 /* Preserve OVERLOADs; the functions must be available to resolve
21252 types. */
21263 /* There is no need to return a proxy for a variable. */
21266 /* Preserve string constants; conversions from string constants to
21267 "char *" are allowed, even though normally a "const char *"
21268 cannot be used to initialize a "char *". */
21271 /* Preserve arithmetic constants, as an optimization -- there is no
21272 reason to create a new node. */
21275 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
21276 There is at least one place where we want to know that a
21277 particular expression is a throw-expression: when checking a ?:
21278 expression, there are special rules if the second or third
21279 argument is a throw-expression. */
21283 /* Don't wrap an initializer list, we need to be able to look inside. */
21287 /* Don't wrap a dummy object, we need to be able to test for it. */
21306 /* If the type is unknown, it can't really be non-dependent */
21309 /* Otherwise, build a NON_DEPENDENT_EXPR. */
21311 }
21313 /* ARGS is a vector of expressions as arguments to a function call.
21314 Replace the arguments with equivalent non-dependent expressions.
21315 This modifies ARGS in place. */
21317 void
21319 {
21321 tree arg;
21324 {
21328 }
21329 }
21331 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
21332 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
21333 parms. */
21335 static tree
21337 {
21350 }
21352 tree
21354 {
21356 }
21358 tree
21360 {
21362 }
21364 /* Given type ARG, return std::initializer_list<ARG>. */
21366 static tree
21368 {
21369 tree std_init_list = namespace_binding
21371 tree argvec;
21373 {
21377 }
21382 }
21384 /* Replace auto in TYPE with std::initializer_list<auto>. */
21386 static tree
21388 {
21395 }
21397 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
21398 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
21400 tree
21402 {
21403 tree targs;
21409 /* Defining a subset of type-dependent expressions that we can deduce
21410 from ahead of time isn't worth the trouble. */
21413 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
21414 with either a new invented type template parameter U or, if the
21415 initializer is a braced-init-list (8.5.4), with
21416 std::initializer_list<U>. */
21424 {
21429 {
21432 }
21433 }
21434 else
21435 {
21446 {
21448 /* Try again at instantiation time. */
21451 /* If type is error_mark_node a diagnostic must have been
21452 emitted by now. Also, having a mention to '<type error>'
21453 in the diagnostic is not really useful to the user. */
21454 {
21458 else
21460 }
21462 }
21463 }
21465 /* If the list of declarators contains more than one declarator, the type
21466 of each declared variable is determined as described above. If the
21467 type deduced for the template parameter U is not the same in each
21468 deduction, the program is ill-formed. */
21471 {
21477 else
21481 }
21487 }
21489 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
21490 result. */
21492 tree
21494 {
21495 tree argvec;
21502 /* For a late-specified return type in a template type-parameter, we
21503 need to add a dummy argument level for its parmlist. */
21504 argvec = add_to_template_args
21509 }
21511 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
21512 'decltype(auto)'. */
21514 bool
21516 {
21521 else
21523 }
21525 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
21526 a use of `auto'. Returns NULL_TREE otherwise. */
21528 tree
21530 {
21532 }
21534 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
21535 'decltype(auto)' or a concept. */
21537 bool
21539 {
21541 }
21543 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
21544 a concept identifier) iff TYPE contains a use of a generic type. Returns
21545 NULL_TREE otherwise. */
21547 tree
21549 {
21551 }
21554 /* For a given template T, return the vector of typedefs referenced
21555 in T for which access check is needed at T instantiation time.
21556 T is either a FUNCTION_DECL or a RECORD_TYPE.
21557 Those typedefs were added to T by the function
21558 append_type_to_template_for_access_check. */
21562 {
21563 tree ti;
21574 {
21579 }
21582 }
21584 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
21585 tied to T. That list of typedefs will be access checked at
21586 T instantiation time.
21587 T is either a FUNCTION_DECL or a RECORD_TYPE.
21588 TYPE_DECL is a TYPE_DECL node representing a typedef.
21589 SCOPE is the scope through which TYPE_DECL is accessed.
21590 LOCATION is the location of the usage point of TYPE_DECL.
21592 This function is a subroutine of
21593 append_type_to_template_for_access_check. */
21595 static void
21597 tree type_decl,
21598 tree scope,
21599 location_t location)
21600 {
21601 qualified_typedef_usage_t typedef_usage;
21602 tree ti;
21609 && type_decl
21623 }
21625 /* Append TYPE_DECL to the template TEMPL.
21626 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
21627 At TEMPL instanciation time, TYPE_DECL will be checked to see
21628 if it can be accessed through SCOPE.
21629 LOCATION is the location of the usage point of TYPE_DECL.
21631 e.g. consider the following code snippet:
21633 class C
21634 {
21635 typedef int myint;
21636 };
21638 template<class U> struct S
21639 {
21640 C::myint mi; // <-- usage point of the typedef C::myint
21641 };
21643 S<char> s;
21645 At S<char> instantiation time, we need to check the access of C::myint
21646 In other words, we need to check the access of the myint typedef through
21647 the C scope. For that purpose, this function will add the myint typedef
21648 and the scope C through which its being accessed to a list of typedefs
21649 tied to the template S. That list will be walked at template instantiation
21650 time and access check performed on each typedefs it contains.
21651 Note that this particular code snippet should yield an error because
21652 myint is private to C. */
21654 void
21656 tree type_decl,
21657 tree scope,
21658 location_t location)
21659 {
21665 /* Make sure we don't append the type to the template twice. */
21672 }
21674 /* Convert the generic type parameters in PARM that match the types given in the
21675 range [START_IDX, END_IDX) from the current_template_parms into generic type
21676 packs. */
21678 tree
21680 {
21691 {
21692 /* Create a distinct parameter pack type from the current parm and add it
21693 to the replacement args to tsubst below into the generic function
21694 parameter. */
21709 }
21715 /* If there are more levels then build up the replacement with the outer
21716 template parms. */
21720 replacement);
21723 }
21726 /* Set up the hash tables for template instantiations. */
21728 void
21730 {
21732 hash_specialization,
21733 eq_specializations,
21734 ggc_free);
21736 hash_specialization,
21737 eq_specializations,
21738 ggc_free);
21739 }
21741 /* Print stats about the template hash tables for -fstats. */
21743 void
21745 {
21754 }