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1 /* Handle parameterized types (templates) for GNU C++.
2 Copyright (C) 1992-2013 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
45 /* The type of functions taking a tree, and some additional data, and
46 returning an int. */
49 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
50 instantiations have been deferred, either because their definitions
51 were not yet available, or because we were putting off doing the work. */
55 };
70 /* Live only within one (recursive) call to tsubst_expr. We use
71 this to pass the statement expression node from the STMT_EXPR
72 to the EXPR_STMT that is its result. */
75 /* A map from local variable declarations in the body of the template
76 presently being instantiated to the corresponding instantiated
77 local variables. */
80 /* True if we've recursed into fn_type_unification too many times. */
84 {
85 tree tmpl;
86 tree args;
87 tree spec;
91 htab_t decl_specializations;
94 htab_t type_specializations;
96 /* Contains canonical template parameter types. The vector is indexed by
97 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
98 TREE_LIST, whose TREE_VALUEs contain the canonical template
99 parameters of various types and levels. */
102 #define UNIFY_ALLOW_NONE 0
103 #define UNIFY_ALLOW_MORE_CV_QUAL 1
104 #define UNIFY_ALLOW_LESS_CV_QUAL 2
105 #define UNIFY_ALLOW_DERIVED 4
106 #define UNIFY_ALLOW_INTEGER 8
107 #define UNIFY_ALLOW_OUTER_LEVEL 16
108 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
109 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
112 tbr_incomplete_type,
113 tbr_ambiguous_baseclass,
114 tbr_success
115 };
138 tree);
200 location_t);
208 /* Make the current scope suitable for access checking when we are
209 processing T. T can be FUNCTION_DECL for instantiated function
210 template, VAR_DECL for static member variable, or TYPE_DECL for
211 alias template (needed by instantiate_decl). */
213 static void
215 {
224 else
228 {
229 saved_access_scope = tree_cons
232 }
233 }
235 /* Restore the scope set up by push_access_scope. T is the node we
236 are processing. */
238 static void
240 {
242 {
245 }
249 else
251 }
253 /* Do any processing required when DECL (a member template
254 declaration) is finished. Returns the TEMPLATE_DECL corresponding
255 to DECL, unless it is a specialization, in which case the DECL
256 itself is returned. */
258 tree
260 {
267 {
268 tree type;
276 {
280 }
282 }
286 {
288 {
291 }
292 else
294 }
295 else
299 }
301 /* Create a template info node. */
303 tree
305 {
310 }
312 /* Return the template info node corresponding to T, whatever T is. */
314 tree
316 {
334 }
336 /* Returns the template nesting level of the indicated class TYPE.
338 For example, in:
339 template <class T>
340 struct A
341 {
342 template <class U>
343 struct B {};
344 };
346 A<T>::B<U> has depth two, while A<T> has depth one.
347 Both A<T>::B<int> and A<int>::B<U> have depth one, if
348 they are instantiations, not specializations.
350 This function is guaranteed to return 0 if passed NULL_TREE so
351 that, for example, `template_class_depth (current_class_type)' is
352 always safe. */
354 int
356 {
363 {
369 }
372 }
374 /* Subroutine of maybe_begin_member_template_processing.
375 Returns true if processing DECL needs us to push template parms. */
377 static bool
379 {
385 }
387 /* Subroutine of maybe_begin_member_template_processing.
388 Push the template parms in PARMS, starting from LEVELS steps into the
389 chain, and ending at the beginning, since template parms are listed
390 innermost first. */
392 static void
394 {
402 current_template_parms
408 NULL);
410 {
419 {
426 {
427 /* Make a CONST_DECL as is done in process_template_parm.
428 It is ugly that we recreate this here; the original
429 version built in process_template_parm is no longer
430 available. */
440 }
445 }
446 }
447 }
449 /* Restore the template parameter context for a member template or
450 a friend template defined in a class definition. */
452 void
454 {
455 tree parms;
459 {
464 {
467 }
470 }
472 /* Remember how many levels of template parameters we pushed so that
473 we can pop them later. */
475 }
477 /* Undo the effects of maybe_begin_member_template_processing. */
479 void
481 {
490 {
494 }
495 }
497 /* Return a new template argument vector which contains all of ARGS,
498 but has as its innermost set of arguments the EXTRA_ARGS. */
500 static tree
502 {
503 tree new_args;
521 }
523 /* Like add_to_template_args, but only the outermost ARGS are added to
524 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
525 (EXTRA_ARGS) levels are added. This function is used to combine
526 the template arguments from a partial instantiation with the
527 template arguments used to attain the full instantiation from the
528 partial instantiation. */
530 static tree
532 {
533 tree new_args;
535 /* If there are more levels of EXTRA_ARGS than there are ARGS,
536 something very fishy is going on. */
539 /* If *all* the new arguments will be the EXTRA_ARGS, just return
540 them. */
544 /* For the moment, we make ARGS look like it contains fewer levels. */
549 /* Now, we restore ARGS to its full dimensions. */
553 }
555 /* Return the N levels of innermost template arguments from the ARGS. */
557 tree
559 {
560 tree new_args;
566 /* If N is 1, just return the innermost set of template arguments. */
570 /* If we're not removing anything, just return the arguments we were
571 given. */
577 /* Make a new set of arguments, not containing the outer arguments. */
584 }
586 /* The inverse of get_innermost_template_args: Return all but the innermost
587 EXTRA_LEVELS levels of template arguments from the ARGS. */
589 static tree
591 {
592 tree new_args;
598 /* If N is 1, just return the outermost set of template arguments. */
602 /* If we're not removing anything, just return the arguments we were
603 given. */
608 /* Make a new set of arguments, not containing the inner arguments. */
615 }
617 /* We've got a template header coming up; push to a new level for storing
618 the parms. */
620 void
622 {
623 /* We use a non-tag-transparent scope here, which causes pushtag to
624 put tags in this scope, rather than in the enclosing class or
625 namespace scope. This is the right thing, since we want
626 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
627 global template class, push_template_decl handles putting the
628 TEMPLATE_DECL into top-level scope. For a nested template class,
629 e.g.:
631 template <class T> struct S1 {
632 template <class T> struct S2 {};
633 };
635 pushtag contains special code to call pushdecl_with_scope on the
636 TEMPLATE_DECL for S2. */
641 }
643 /* This routine is called when a specialization is declared. If it is
644 invalid to declare a specialization here, an error is reported and
645 false is returned, otherwise this routine will return true. */
647 static bool
649 {
652 /* [temp.expl.spec]
654 An explicit specialization shall be declared in the namespace of
655 which the template is a member, or, for member templates, in the
656 namespace of which the enclosing class or enclosing class
657 template is a member. An explicit specialization of a member
658 function, member class or static data member of a class template
659 shall be declared in the namespace of which the class template
660 is a member. */
662 {
665 }
667 /* [temp.expl.spec]
669 In an explicit specialization declaration for a member of a class
670 template or a member template that appears in namespace scope,
671 the member template and some of its enclosing class templates may
672 remain unspecialized, except that the declaration shall not
673 explicitly specialize a class member template if its enclosing
674 class templates are not explicitly specialized as well. */
676 {
679 }
682 }
684 /* We've just seen template <>. */
686 bool
688 {
692 }
694 /* Called at then end of processing a declaration preceded by
695 template<>. */
697 void
699 {
702 }
704 /* Any template <>'s that we have seen thus far are not referring to a
705 function specialization. */
707 void
709 {
712 }
714 /* We've just seen a template header. If SPECIALIZATION is nonzero,
715 it was of the form template <>. */
717 static void
719 {
721 template_header_count++;
722 }
724 /* We're beginning an explicit instantiation. */
726 void
728 {
731 }
734 void
736 {
739 }
741 /* An explicit specialization or partial specialization of TMPL is being
742 declared. Check that the namespace in which the specialization is
743 occurring is permissible. Returns false iff it is invalid to
744 specialize TMPL in the current namespace. */
746 static bool
748 {
751 /* [tmpl.expl.spec]
753 An explicit specialization shall be declared in the namespace of
754 which the template is a member, or, for member templates, in the
755 namespace of which the enclosing class or enclosing class
756 template is a member. An explicit specialization of a member
757 function, member class or static data member of a class template
758 shall be declared in the namespace of which the class template is
759 a member. */
762 {
765 }
767 /* Same or super-using namespace. */
769 else
770 {
774 }
775 }
777 /* SPEC is an explicit instantiation. Check that it is valid to
778 perform this explicit instantiation in the current namespace. */
780 static void
782 {
783 tree ns;
785 /* DR 275: An explicit instantiation shall appear in an enclosing
786 namespace of its template. */
792 }
794 /* The TYPE is being declared. If it is a template type, that means it
795 is a partial specialization. Do appropriate error-checking. */
797 tree
799 {
800 tree context;
806 {
810 }
815 {
820 else
823 }
825 {
826 /* This is for ordinary explicit specialization and partial
827 specialization of a template class such as:
829 template <> class C<int>;
831 or:
833 template <class T> class C<T*>;
835 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
839 {
844 {
848 }
849 }
855 /* Trying to define a specialization either without a template<> header
856 or in an inappropriate place. We've already given an error, so just
857 bail now so we don't actually define the specialization. */
859 }
865 {
866 /* This is for an explicit specialization of member class
867 template according to [temp.expl.spec/18]:
869 template <> template <class U> class C<int>::D;
871 The context `C<int>' must be an implicit instantiation.
872 Otherwise this is just a member class template declared
873 earlier like:
875 template <> class C<int> { template <class U> class D; };
876 template <> template <class U> class C<int>::D;
878 In the first case, `C<int>::D' is a specialization of `C<T>::D'
879 while in the second case, `C<int>::D' is a primary template
880 and `C<T>::D' may not exist. */
884 {
885 tree t;
890 {
893 }
895 /* Check for invalid specialization after instantiation:
897 template <> template <> class C<int>::D<int>;
898 template <> template <class U> class C<int>::D; */
902 {
905 {
906 /* We already have a full specialization of this partial
907 instantiation. Reassign it to the new member
908 specialization template. */
909 spec_entry elt;
926 }
928 /* But if we've had an implicit instantiation, that's a
929 problem ([temp.expl.spec]/6). */
932 }
934 /* Mark TYPE as a specialization. And as a result, we only
935 have one level of template argument for the innermost
936 class template. */
941 }
942 }
944 {
945 /* Someday C++0x may allow for enum template specialization. */
950 else
951 {
954 }
955 }
958 }
960 /* Returns nonzero if we can optimize the retrieval of specializations
961 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
962 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
966 {
969 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
970 parameter. */
972 /* The optimized lookup depends on the fact that the
973 template arguments for the member function template apply
974 purely to the containing class, which is not true if the
975 containing class is an explicit or partial
976 specialization. */
980 /* It is possible to have a template that is not a member
981 template and is not a member of a template class:
983 template <typename T>
984 struct S { friend A::f(); };
986 Here, the friend function is a template, but the context does
987 not have template information. The optimized lookup relies
988 on having ARGS be the template arguments for both the class
989 and the function template. */
991 }
993 /* Retrieve the specialization (in the sense of [temp.spec] - a
994 specialization is either an instantiation or an explicit
995 specialization) of TMPL for the given template ARGS. If there is
996 no such specialization, return NULL_TREE. The ARGS are a vector of
997 arguments, or a vector of vectors of arguments, in the case of
998 templates with more than one level of parameters.
1000 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1001 then we search for a partial specialization matching ARGS. This
1002 parameter is ignored if TMPL is not a class template. */
1004 static tree
1006 {
1012 /* There should be as many levels of arguments as there are
1013 levels of parameters. */
1018 {
1019 tree class_template;
1020 tree class_specialization;
1022 tree fns;
1025 /* The template arguments actually apply to the containing
1026 class. Find the class specialization with those
1027 arguments. */
1029 class_specialization
1033 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1034 for the specialization. */
1038 /* Iterate through the methods with the indicated name, looking
1039 for the one that has an instance of TMPL. */
1042 {
1045 /* using-declarations can add base methods to the method vec,
1046 and we don't want those here. */
1049 }
1051 }
1052 else
1053 {
1055 spec_entry elt;
1056 htab_t specializations;
1064 else
1072 }
1075 }
1077 /* Like retrieve_specialization, but for local declarations. */
1079 static tree
1081 {
1089 }
1091 /* Returns nonzero iff DECL is a specialization of TMPL. */
1093 int
1095 {
1096 tree t;
1099 {
1105 }
1106 else
1107 {
1116 }
1119 }
1121 /* Returns nonzero iff DECL is a specialization of friend declaration
1122 FRIEND_DECL according to [temp.friend]. */
1124 bool
1126 {
1133 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1134 of a template class, we want to check if DECL is a specialization
1135 if this. */
1139 {
1140 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1143 }
1148 /* There is nothing to do if this is not a template friend. */
1155 /* [temp.friend/6]
1156 A member of a class template may be declared to be a friend of a
1157 non-template class. In this case, the corresponding member of
1158 every specialization of the class template is a friend of the
1159 class granting friendship.
1161 For example, given a template friend declaration
1163 template <class T> friend void A<T>::f();
1165 the member function below is considered a friend
1167 template <> struct A<int> {
1168 void f();
1169 };
1171 For this type of template friend, TEMPLATE_DEPTH below will be
1172 nonzero. To determine if DECL is a friend of FRIEND, we first
1173 check if the enclosing class is a specialization of another. */
1180 {
1181 /* Next, we check the members themselves. In order to handle
1182 a few tricky cases, such as when FRIEND_DECL's are
1184 template <class T> friend void A<T>::g(T t);
1185 template <class T> template <T t> friend void A<T>::h();
1187 and DECL's are
1189 void A<int>::g(int);
1190 template <int> void A<int>::h();
1192 we need to figure out ARGS, the template arguments from
1193 the context of DECL. This is required for template substitution
1194 of `T' in the function parameter of `g' and template parameter
1195 of `h' in the above examples. Here ARGS corresponds to `int'. */
1202 {
1204 {
1207 else
1209 current_depth++;
1210 }
1212 }
1215 {
1217 tree friend_type;
1218 tree decl_type;
1219 tree friend_args_type;
1220 tree decl_args_type;
1222 /* Make sure that both DECL and FRIEND_DECL are templates or
1223 non-templates. */
1229 {
1230 /* If both are templates, check template parameter list. */
1231 tree friend_parms
1236 friend_parms))
1240 }
1241 else
1249 /* Check if return types match. */
1253 /* Check if function parameter types match, ignoring the
1254 `this' parameter. */
1263 }
1264 else
1265 {
1266 /* DECL is a TYPE_DECL */
1270 /* Make sure that both DECL and FRIEND_DECL are templates or
1271 non-templates. */
1272 is_template
1279 {
1280 tree friend_parms;
1281 /* If both are templates, check the name of the two
1282 TEMPLATE_DECL's first because is_friend didn't. */
1287 /* Now check template parameter list. */
1288 friend_parms
1291 return comp_template_parms
1293 friend_parms);
1294 }
1295 else
1298 }
1299 }
1301 }
1303 /* Register the specialization SPEC as a specialization of TMPL with
1304 the indicated ARGS. IS_FRIEND indicates whether the specialization
1305 is actually just a friend declaration. Returns SPEC, or an
1306 equivalent prior declaration, if available. */
1308 static tree
1310 hashval_t hash)
1311 {
1312 tree fn;
1314 spec_entry elt;
1320 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1321 register it; we want the corresponding TEMPLATE_DECL instead.
1322 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1323 the more obvious `uses_template_parms (spec)' to avoid problems
1324 with default function arguments. In particular, given
1325 something like this:
1327 template <class T> void f(T t1, T t = T())
1329 the default argument expression is not substituted for in an
1330 instantiation unless and until it is actually needed. */
1334 /* We don't put these specializations in the hash table, but we might
1335 want to give an error about a mismatch. */
1337 else
1338 {
1346 slot =
1350 else
1352 }
1354 /* We can sometimes try to re-register a specialization that we've
1355 already got. In particular, regenerate_decl_from_template calls
1356 duplicate_decls which will update the specialization list. But,
1357 we'll still get called again here anyhow. It's more convenient
1358 to simply allow this than to try to prevent it. */
1362 {
1364 {
1367 {
1369 fn);
1371 }
1372 else
1373 {
1374 tree clone;
1375 /* This situation should occur only if the first
1376 specialization is an implicit instantiation, the
1377 second is an explicit specialization, and the
1378 implicit instantiation has not yet been used. That
1379 situation can occur if we have implicitly
1380 instantiated a member function and then specialized
1381 it later.
1383 We can also wind up here if a friend declaration that
1384 looked like an instantiation turns out to be a
1385 specialization:
1387 template <class T> void foo(T);
1388 class S { friend void foo<>(int) };
1389 template <> void foo(int);
1391 We transform the existing DECL in place so that any
1392 pointers to it become pointers to the updated
1393 declaration.
1395 If there was a definition for the template, but not
1396 for the specialization, we want this to look as if
1397 there were no definition, and vice versa. */
1400 /* The call to duplicate_decls will have applied
1401 [temp.expl.spec]:
1403 An explicit specialization of a function template
1404 is inline only if it is explicitly declared to be,
1405 and independently of whether its function template
1406 is.
1408 to the primary function; now copy the inline bits to
1409 the various clones. */
1411 {
1416 }
1420 }
1421 }
1423 {
1425 /* Dup decl failed, but this is a new definition. Set the
1426 line number so any errors match this new
1427 definition. */
1431 }
1432 }
1436 /* A specialization must be declared in the same namespace as the
1437 template it is specializing. */
1443 {
1451 /* TMPL is a forward declaration of a template function; keep a list
1452 of all specializations in case we need to reassign them to a friend
1453 template later in tsubst_friend_function. */
1456 }
1459 }
1461 /* Returns true iff two spec_entry nodes are equivalent. Only compares the
1462 TMPL and ARGS members, ignores SPEC. */
1464 static int
1466 {
1472 }
1474 /* Returns a hash for a template TMPL and template arguments ARGS. */
1476 static hashval_t
1478 {
1481 }
1483 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1484 ignoring SPEC. */
1486 static hashval_t
1488 {
1491 }
1493 /* Recursively calculate a hash value for a template argument ARG, for use
1494 in the hash tables of template specializations. */
1496 hashval_t
1498 {
1510 /* We can get one of these when re-hashing a previous entry in the middle
1511 of substituting into a pack expansion. Just look through it. */
1520 {
1528 {
1533 }
1555 {
1558 {
1561 }
1563 }
1567 {
1570 }
1581 val = iterative_hash_template_arg
1593 val);
1595 val);
1604 /* A lambda can't appear in a template arg, but don't crash on
1605 erroneous input. */
1617 /* Now hash operands as usual. */
1622 }
1625 {
1629 val);
1632 /* Otherwise just compare the types during lookup. */
1641 {
1646 }
1647 }
1650 }
1652 /* Unregister the specialization SPEC as a specialization of TMPL.
1653 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1654 if the SPEC was listed as a specialization of TMPL.
1656 Note that SPEC has been ggc_freed, so we can't look inside it. */
1658 bool
1660 {
1662 spec_entry elt;
1670 {
1675 }
1678 }
1680 /* Like register_specialization, but for local declarations. We are
1681 registering SPEC, an instantiation of TMPL. */
1683 static void
1685 {
1690 }
1692 /* TYPE is a class type. Returns true if TYPE is an explicitly
1693 specialized class. */
1695 bool
1697 {
1701 }
1703 /* Print the list of functions at FNS, going through all the overloads
1704 for each element of the list. Alternatively, FNS can not be a
1705 TREE_LIST, in which case it will be printed together with all the
1706 overloads.
1708 MORE and *STR should respectively be FALSE and NULL when the function
1709 is called from the outside. They are used internally on recursive
1710 calls. print_candidates manages the two parameters and leaves NULL
1711 in *STR when it ends. */
1713 static void
1715 {
1721 {
1725 }
1726 else
1727 {
1730 {
1731 /* Pick the prefix string. */
1733 {
1737 }
1741 }
1744 }
1747 {
1750 }
1751 }
1753 /* Print the list of candidate FNS in an error message. FNS can also
1754 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1756 void
1758 {
1762 }
1764 /* Returns the template (one of the functions given by TEMPLATE_ID)
1765 which can be specialized to match the indicated DECL with the
1766 explicit template args given in TEMPLATE_ID. The DECL may be
1767 NULL_TREE if none is available. In that case, the functions in
1768 TEMPLATE_ID are non-members.
1770 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1771 specialization of a member template.
1773 The TEMPLATE_COUNT is the number of references to qualifying
1774 template classes that appeared in the name of the function. See
1775 check_explicit_specialization for a more accurate description.
1777 TSK indicates what kind of template declaration (if any) is being
1778 declared. TSK_TEMPLATE indicates that the declaration given by
1779 DECL, though a FUNCTION_DECL, has template parameters, and is
1780 therefore a template function.
1782 The template args (those explicitly specified and those deduced)
1783 are output in a newly created vector *TARGS_OUT.
1785 If it is impossible to determine the result, an error message is
1786 issued. The error_mark_node is returned to indicate failure. */
1788 static tree
1790 tree decl,
1794 tmpl_spec_kind tsk)
1795 {
1796 tree fns;
1797 tree targs;
1798 tree explicit_targs;
1800 /* A TREE_LIST of templates of which DECL may be a specialization.
1801 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1802 corresponding TREE_PURPOSE is the set of template arguments that,
1803 when used to instantiate the template, would produce a function
1804 with the signature of DECL. */
1814 /* We shouldn't be specializing a member template of an
1815 unspecialized class template; we already gave an error in
1816 check_specialization_scope, now avoid crashing. */
1819 {
1822 }
1830 /* Check for baselinks. */
1835 {
1838 }
1840 /* Count the number of template headers specified for this
1841 specialization. */
1849 {
1853 {
1854 tree decl_arg_types;
1855 tree fn_arg_types;
1856 tree insttype;
1858 /* In case of explicit specialization, we need to check if
1859 the number of template headers appearing in the specialization
1860 is correct. This is usually done in check_explicit_specialization,
1861 but the check done there cannot be exhaustive when specializing
1862 member functions. Consider the following code:
1864 template <> void A<int>::f(int);
1865 template <> template <> void A<int>::f(int);
1867 Assuming that A<int> is not itself an explicit specialization
1868 already, the first line specializes "f" which is a non-template
1869 member function, whilst the second line specializes "f" which
1870 is a template member function. So both lines are syntactically
1871 correct, and check_explicit_specialization does not reject
1872 them.
1874 Here, we can do better, as we are matching the specialization
1875 against the declarations. We count the number of template
1876 headers, and we check if they match TEMPLATE_COUNT + 1
1877 (TEMPLATE_COUNT is the number of qualifying template classes,
1878 plus there must be another header for the member template
1879 itself).
1881 Notice that if header_count is zero, this is not a
1882 specialization but rather a template instantiation, so there
1883 is no check we can perform here. */
1887 /* Check that the number of template arguments at the
1888 innermost level for DECL is the same as for FN. */
1896 /* DECL might be a specialization of FN. */
1900 /* For a non-static member function, we need to make sure
1901 that the const qualification is the same. Since
1902 get_bindings does not try to merge the "this" parameter,
1903 we must do the comparison explicitly. */
1909 /* Skip the "this" parameter and, for constructors of
1910 classes with virtual bases, the VTT parameter. A
1911 full specialization of a constructor will have a VTT
1912 parameter, but a template never will. */
1913 decl_arg_types
1915 fn_arg_types
1918 /* Function templates cannot be specializations; there are
1919 no partial specializations of functions. Therefore, if
1920 the type of DECL does not match FN, there is no
1921 match. */
1923 {
1927 }
1929 /* See whether this function might be a specialization of this
1930 template. Suppress access control because we might be trying
1931 to make this specialization a friend, and we have already done
1932 access control for the declaration of the specialization. */
1938 /* We cannot deduce template arguments that when used to
1939 specialize TMPL will produce DECL. */
1942 /* Make sure that the deduced arguments actually work. */
1946 fn_arg_types
1951 /* Save this template, and the arguments deduced. */
1953 }
1955 /* FN is an ordinary member function, and we need a
1956 specialization of a member template. */
1957 ;
1959 /* We can get IDENTIFIER_NODEs here in certain erroneous
1960 cases. */
1961 ;
1963 /* This is just an ordinary non-member function. Nothing can
1964 be a specialization of that. */
1965 ;
1967 /* Cannot specialize functions that are created implicitly. */
1968 ;
1969 else
1970 {
1971 tree decl_arg_types;
1973 /* This is an ordinary member function. However, since
1974 we're here, we can assume it's enclosing class is a
1975 template class. For example,
1977 template <typename T> struct S { void f(); };
1978 template <> void S<int>::f() {}
1980 Here, S<int>::f is a non-template, but S<int> is a
1981 template class. If FN has the same type as DECL, we
1982 might be in business. */
1985 /* Its enclosing class is an explicit specialization
1986 of a template class. This is not a candidate. */
1991 /* The return types differ. */
1994 /* Adjust the type of DECL in case FN is a static member. */
2001 decl_arg_types))
2002 /* They match! */
2004 }
2005 }
2008 {
2009 /* We have:
2011 [temp.expl.spec]
2013 It is possible for a specialization with a given function
2014 signature to be instantiated from more than one function
2015 template. In such cases, explicit specification of the
2016 template arguments must be used to uniquely identify the
2017 function template specialization being specialized.
2019 Note that here, there's no suggestion that we're supposed to
2020 determine which of the candidate templates is most
2021 specialized. However, we, also have:
2023 [temp.func.order]
2025 Partial ordering of overloaded function template
2026 declarations is used in the following contexts to select
2027 the function template to which a function template
2028 specialization refers:
2030 -- when an explicit specialization refers to a function
2031 template.
2033 So, we do use the partial ordering rules, at least for now.
2034 This extension can only serve to make invalid programs valid,
2035 so it's safe. And, there is strong anecdotal evidence that
2036 the committee intended the partial ordering rules to apply;
2037 the EDG front end has that behavior, and John Spicer claims
2038 that the committee simply forgot to delete the wording in
2039 [temp.expl.spec]. */
2042 {
2045 }
2046 }
2049 {
2057 }
2061 {
2067 }
2069 /* We have one, and exactly one, match. */
2071 {
2074 /* DECL is a re-declaration or partial instantiation of a template
2075 function. */
2078 /* It was a specialization of an ordinary member function in a
2079 template class. */
2081 }
2083 /* It was a specialization of a template. */
2086 {
2091 }
2092 else
2095 }
2097 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2098 but with the default argument values filled in from those in the
2099 TMPL_TYPES. */
2101 static tree
2103 tree tmpl_types)
2104 {
2105 tree new_spec_types;
2113 /* Substitute into the rest of the list. */
2114 new_spec_types =
2118 /* Add the default argument for this parameter. */
2121 new_spec_types);
2122 }
2124 /* DECL is an explicit specialization. Replicate default arguments
2125 from the template it specializes. (That way, code like:
2127 template <class T> void f(T = 3);
2128 template <> void f(double);
2129 void g () { f (); }
2131 works, as required.) An alternative approach would be to look up
2132 the correct default arguments at the call-site, but this approach
2133 is consistent with how implicit instantiations are handled. */
2135 static void
2137 {
2138 tree tmpl;
2139 tree spec_types;
2140 tree tmpl_types;
2141 tree new_spec_types;
2142 tree old_type;
2143 tree new_type;
2144 tree t;
2149 /* See if there's anything we need to do. */
2162 {
2163 /* Remove the this pointer, but remember the object's type for
2164 CV quals. */
2170 {
2171 /* DECL may contain more parameters than TMPL due to the extra
2172 in-charge parameter in constructors and destructors. */
2175 }
2177 {
2180 }
2181 }
2183 /* Compute the merged default arguments. */
2184 new_spec_types =
2187 /* Compute the new FUNCTION_TYPE. */
2189 {
2193 new_spec_types);
2196 /* Put the in-charge parameter back. */
2199 new_spec_types);
2203 new_spec_types);
2204 }
2205 else
2207 new_spec_types);
2213 }
2215 /* Return the number of template headers we expect to see for a definition
2216 or specialization of CTYPE or one of its non-template members. */
2218 int
2220 {
2224 {
2225 /* You're supposed to have one `template <...>' for every
2226 template class, but you don't need one for a full
2227 specialization. For example:
2229 template <class T> struct S{};
2230 template <> struct S<int> { void f(); };
2231 void S<int>::f () {}
2233 is correct; there shouldn't be a `template <>' for the
2234 definition of `S<int>::f'. */
2236 /* If CTYPE does not have template information of any
2237 kind, then it is not a template, nor is it nested
2238 within a template. */
2246 }
2249 }
2251 /* Do a simple sanity check on the template headers that precede the
2252 variable declaration DECL. */
2254 void
2256 {
2263 {
2269 "members of an explicitly specialized class are defined "
2271 }
2272 }
2274 /* Check to see if the function just declared, as indicated in
2275 DECLARATOR, and in DECL, is a specialization of a function
2276 template. We may also discover that the declaration is an explicit
2277 instantiation at this point.
2279 Returns DECL, or an equivalent declaration that should be used
2280 instead if all goes well. Issues an error message if something is
2281 amiss. Returns error_mark_node if the error is not easily
2282 recoverable.
2284 FLAGS is a bitmask consisting of the following flags:
2286 2: The function has a definition.
2287 4: The function is a friend.
2289 The TEMPLATE_COUNT is the number of references to qualifying
2290 template classes that appeared in the name of the function. For
2291 example, in
2293 template <class T> struct S { void f(); };
2294 void S<int>::f();
2296 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2297 classes are not counted in the TEMPLATE_COUNT, so that in
2299 template <class T> struct S {};
2300 template <> struct S<int> { void f(); }
2301 template <> void S<int>::f();
2303 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2304 invalid; there should be no template <>.)
2306 If the function is a specialization, it is marked as such via
2307 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2308 is set up correctly, and it is added to the list of specializations
2309 for that template. */
2311 tree
2313 tree decl,
2316 {
2324 tmpl_spec_kind tsk;
2327 {
2330 else
2332 }
2333 else
2337 {
2340 {
2343 }
2345 {
2347 /* This could be something like:
2349 template <class T> void f(T);
2350 class S { friend void f<>(int); } */
2352 else
2353 {
2354 /* This case handles bogus declarations like template <>
2355 template <class T> void f<int>(); */
2358 declarator);
2360 }
2361 }
2365 /* The error has already been reported in
2366 check_specialization_scope. */
2372 /* Fall through. */
2385 decl);
2388 else
2392 /* Fall through. */
2397 else
2403 {
2404 /* This case handles bogus declarations like template <>
2405 template <class T> void f<int>(); */
2410 else
2412 declarator);
2414 }
2417 /* This is a specialization of a member template, without
2418 specialization the containing class. Something like:
2420 template <class T> struct S {
2421 template <class U> void f (U);
2422 };
2423 template <> template <class U> void S<int>::f(U) {}
2425 That's a specialization -- but of the entire template. */
2431 }
2434 {
2438 {
2442 }
2443 }
2446 {
2450 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2452 {
2453 tree fns;
2458 else
2459 {
2460 /* If there is no class context, the explicit instantiation
2461 must be at namespace scope. */
2464 /* Find the namespace binding, using the declaration
2465 context. */
2469 {
2472 }
2473 else
2474 {
2480 }
2481 }
2484 }
2490 {
2492 /* A specialization in class scope. This is invalid,
2493 but the error will already have been flagged by
2494 check_specialization_scope. */
2496 else
2497 {
2498 /* It's not valid to write an explicit instantiation in
2499 class scope, e.g.:
2501 class C { template void f(); }
2503 This case is caught by the parser. However, on
2504 something like:
2506 template class C { void f(); };
2508 (which is invalid) we can get here. The error will be
2509 issued later. */
2510 ;
2511 }
2514 }
2517 IDENTIFIER_NODE))
2518 {
2519 /* Find the list of functions in ctype that have the same
2520 name as the declared function. */
2526 {
2531 {
2532 /* From [temp.expl.spec]:
2534 If such an explicit specialization for the member
2535 of a class template names an implicitly-declared
2536 special member function (clause _special_), the
2537 program is ill-formed.
2539 Similar language is found in [temp.explicit]. */
2542 }
2545 }
2548 {
2552 }
2553 else
2554 {
2556 tree ovl;
2558 /* For a type-conversion operator, we cannot do a
2559 name-based lookup. We might be looking for `operator
2560 int' which will be a specialization of `operator T'.
2561 So, we find *all* the conversion operators, and then
2562 select from them. */
2570 {
2572 /* There are no more conversion functions. */
2575 /* Glue all these conversion functions together
2576 with those we already have. */
2579 }
2580 }
2583 {
2586 }
2587 else
2589 }
2591 /* Figure out what exactly is being specialized at this point.
2592 Note that for an explicit instantiation, even one for a
2593 member function, we cannot tell apriori whether the
2594 instantiation is for a member template, or just a member
2595 function of a template class. Even if a member template is
2596 being instantiated, the member template arguments may be
2597 elided if they can be deduced from the rest of the
2598 declaration. */
2601 member_specialization,
2602 template_count,
2603 tsk);
2606 /* We couldn't figure out what this declaration was
2607 specializing. */
2609 else
2610 {
2614 {
2615 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2616 is done by do_decl_instantiation later. */
2622 {
2623 /* If TMPL is not the most general template (for
2624 example, if TMPL is a friend template that is
2625 injected into namespace scope), then there will
2626 be too many levels of TARGS. Remove some of them
2627 here. */
2629 tree new_targs;
2636 }
2639 }
2641 /* If we thought that the DECL was a member function, but it
2642 turns out to be specializing a static member function,
2643 make DECL a static member function as well. */
2648 /* If this is a specialization of a member template of a
2649 template class, we want to return the TEMPLATE_DECL, not
2650 the specialization of it. */
2652 {
2657 {
2658 tree parm;
2662 /* We want to use the argument list specified in the
2663 definition, not in the original declaration. */
2668 }
2671 }
2673 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2676 /* Inherit default function arguments from the template
2677 DECL is specializing. */
2680 /* This specialization has the same protection as the
2681 template it specializes. */
2685 /* 7.1.1-1 [dcl.stc]
2687 A storage-class-specifier shall not be specified in an
2688 explicit specialization...
2690 The parser rejects these, so unless action is taken here,
2691 explicit function specializations will always appear with
2692 global linkage.
2694 The action recommended by the C++ CWG in response to C++
2695 defect report 605 is to make the storage class and linkage
2696 of the explicit specialization match the templated function:
2698 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2699 */
2701 {
2705 /* This specialization has the same linkage and visibility as
2706 the function template it specializes. */
2709 {
2712 }
2715 {
2718 }
2719 }
2721 /* If DECL is a friend declaration, declared using an
2722 unqualified name, the namespace associated with DECL may
2723 have been set incorrectly. For example, in:
2725 template <typename T> void f(T);
2726 namespace N {
2727 struct S { friend void f<int>(int); }
2728 }
2730 we will have set the DECL_CONTEXT for the friend
2731 declaration to N, rather than to the global namespace. */
2736 /* This is not really a declaration of a specialization.
2737 It's just the name of an instantiation. But, it's not
2738 a request for an instantiation, either. */
2741 /* This is indeed a specialization. In case of constructors
2742 and destructors, we need in-charge and not-in-charge
2743 versions in V3 ABI. */
2746 /* Register this specialization so that we can find it
2747 again. */
2749 }
2750 }
2753 }
2755 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2756 parameters. These are represented in the same format used for
2757 DECL_TEMPLATE_PARMS. */
2759 int
2761 {
2762 const_tree p1;
2763 const_tree p2;
2771 {
2783 {
2787 /* If either of the template parameters are invalid, assume
2788 they match for the sake of error recovery. */
2801 }
2802 }
2805 /* One set of parameters has more parameters lists than the
2806 other. */
2810 }
2812 /* Determine whether PARM is a parameter pack. */
2814 bool
2816 {
2817 /* Determine if we have a non-type template parameter pack. */
2824 /* If this is a list of template parameters, we could get a
2825 TYPE_DECL or a TEMPLATE_DECL. */
2829 /* Otherwise it must be a type template parameter. */
2833 }
2835 /* Determine if T is a function parameter pack. */
2837 bool
2839 {
2843 }
2845 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
2846 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
2848 tree
2850 {
2857 }
2859 /* Return true iff the function parameter PARAM_DECL was expanded
2860 from the function parameter pack PACK. */
2862 bool
2864 {
2869 /* The parameter pack and its pack arguments have the same
2870 DECL_PARM_INDEX. */
2872 }
2874 /* Determine whether ARGS describes a variadic template args list,
2875 i.e., one that is terminated by a template argument pack. */
2877 static bool
2879 {
2881 tree last_parm;
2895 }
2897 /* Generate a new name for the parameter pack name NAME (an
2898 IDENTIFIER_NODE) that incorporates its */
2900 static tree
2902 {
2903 /* Munge the name to include the parameter index. */
2904 #define NUMBUF_LEN 128
2918 }
2920 /* Return true if T is a primary function, class or alias template
2921 instantiation. */
2923 bool
2925 {
2939 }
2941 /* Return true if PARM is a template template parameter. */
2943 bool
2945 {
2947 }
2949 /* Return true iff PARM is a DECL representing a type template
2950 parameter. */
2952 bool
2954 {
2959 }
2961 /* Return the template parameters of T if T is a
2962 primary template instantiation, NULL otherwise. */
2964 tree
2966 {
2971 parms = INNERMOST_TEMPLATE_PARMS
2975 }
2977 /* Return the template parameters of the LEVELth level from the full list
2978 of template parameters PARMS. */
2980 tree
2982 {
2983 tree p;
2994 }
2996 /* Returns the template arguments of T if T is a template instantiation,
2997 NULL otherwise. */
2999 tree
3001 {
3009 }
3011 /* Return the argument pack elements of T if T is a template argument pack,
3012 NULL otherwise. */
3014 tree
3016 {
3022 }
3024 /* Structure used to track the progress of find_parameter_packs_r. */
3025 struct find_parameter_pack_data
3026 {
3027 /* TREE_LIST that will contain all of the parameter packs found by
3028 the traversal. */
3031 /* Set of AST nodes that have been visited by the traversal. */
3033 };
3035 /* Identifies all of the argument packs that occur in a template
3036 argument and appends them to the TREE_LIST inside DATA, which is a
3037 find_parameter_pack_data structure. This is a subroutine of
3038 make_pack_expansion and uses_parameter_packs. */
3039 static tree
3041 {
3047 /* Handle type aliases/typedefs. */
3052 {
3059 }
3061 /* Identify whether this is a parameter pack or not. */
3063 {
3078 {
3079 /* We don't want to walk into the type of a PARM_DECL,
3080 because we don't want to see the type parameter pack. */
3083 }
3090 /* Not a parameter pack. */
3092 }
3095 {
3096 /* Add this parameter pack to the list. */
3098 }
3104 /* This switch statement will return immediately if we don't find a
3105 parameter pack. */
3107 {
3112 /* Check the template itself. */
3115 /* Check the template arguments. */
3131 /* Fall through. */
3173 }
3176 }
3178 /* Determines if the expression or type T uses any parameter packs. */
3179 bool
3181 {
3189 }
3191 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3192 representation a base-class initializer into a parameter pack
3193 expansion. If all goes well, the resulting node will be an
3194 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3195 respectively. */
3196 tree
3198 {
3199 tree result;
3208 {
3209 /* The only time we will see a TREE_LIST here is for a base
3210 class initializer. In this case, the TREE_PURPOSE will be a
3211 _TYPE node (representing the base class expansion we're
3212 initializing) and the TREE_VALUE will be a TREE_LIST
3213 containing the initialization arguments.
3215 The resulting expansion looks somewhat different from most
3216 expansions. Rather than returning just one _EXPANSION, we
3217 return a TREE_LIST whose TREE_PURPOSE is a
3218 TYPE_PACK_EXPANSION containing the bases that will be
3219 initialized. The TREE_VALUE will be identical to the
3220 original TREE_VALUE, which is a list of arguments that will
3221 be passed to each base. We do not introduce any new pack
3222 expansion nodes into the TREE_VALUE (although it is possible
3223 that some already exist), because the TREE_PURPOSE and
3224 TREE_VALUE all need to be expanded together with the same
3225 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3226 resulting TREE_PURPOSE will mention the parameter packs in
3227 both the bases and the arguments to the bases. */
3228 tree purpose;
3229 tree value;
3232 /* Determine which parameter packs will be used by the base
3233 class expansion. */
3240 {
3244 }
3247 {
3248 /* Collect the sets of parameter packs used in each of the
3249 initialization arguments. */
3251 {
3252 /* Determine which parameter packs will be expanded in this
3253 argument. */
3256 }
3257 }
3261 /* Create the pack expansion type for the base type. */
3266 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3267 they will rarely be compared to anything. */
3271 }
3276 /* Build the PACK_EXPANSION_* node. */
3277 result = for_types
3282 {
3283 /* Propagate type and const-expression information. */
3286 }
3287 else
3288 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3289 they will rarely be compared to anything. */
3292 /* Determine which parameter packs will be expanded. */
3298 /* Make sure we found some parameter packs. */
3300 {
3303 else
3306 }
3312 }
3314 /* Checks T for any "bare" parameter packs, which have not yet been
3315 expanded, and issues an error if any are found. This operation can
3316 only be done on full expressions or types (e.g., an expression
3317 statement, "if" condition, etc.), because we could have expressions like:
3319 foo(f(g(h(args)))...)
3321 where "args" is a parameter pack. check_for_bare_parameter_packs
3322 should not be called for the subexpressions args, h(args),
3323 g(h(args)), or f(g(h(args))), because we would produce erroneous
3324 error messages.
3326 Returns TRUE and emits an error if there were bare parameter packs,
3327 returns FALSE otherwise. */
3328 bool
3330 {
3346 {
3349 {
3358 else
3363 else
3367 }
3370 }
3373 }
3375 /* Expand any parameter packs that occur in the template arguments in
3376 ARGS. */
3377 tree
3379 {
3385 /* First, determine if we need to expand anything, and the number of
3386 slots we'll need. */
3388 {
3393 {
3397 else
3399 }
3400 else
3401 {
3403 num_result_args++;
3404 }
3405 }
3407 /* If no expansion is necessary, we're done. */
3411 /* Expand arguments. */
3414 non_default_args_count =
3417 {
3420 {
3427 }
3428 else
3429 {
3432 }
3433 }
3437 }
3439 /* Checks if DECL shadows a template parameter.
3441 [temp.local]: A template-parameter shall not be redeclared within its
3442 scope (including nested scopes).
3444 Emits an error and returns TRUE if the DECL shadows a parameter,
3445 returns FALSE otherwise. */
3447 bool
3449 {
3450 tree olddecl;
3452 /* If we're not in a template, we can't possibly shadow a template
3453 parameter. */
3457 /* Figure out what we're shadowing. */
3462 /* If there's no previous binding for this name, we're not shadowing
3463 anything, let alone a template parameter. */
3467 /* If we're not shadowing a template parameter, we're done. Note
3468 that OLDDECL might be an OVERLOAD (or perhaps even an
3469 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3470 node. */
3474 /* We check for decl != olddecl to avoid bogus errors for using a
3475 name inside a class. We check TPFI to avoid duplicate errors for
3476 inline member templates. */
3484 }
3486 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3487 ORIG_LEVEL, DECL, and TYPE. */
3489 static tree
3493 tree decl,
3494 tree type)
3495 {
3506 }
3508 /* Find the canonical type parameter for the given template type
3509 parameter. Returns the canonical type parameter, which may be TYPE
3510 if no such parameter existed. */
3512 static tree
3514 {
3515 tree list;
3529 else
3530 {
3535 }
3536 }
3538 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3539 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3540 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3541 new one is created. */
3543 static tree
3545 tsubst_flags_t complain)
3546 {
3551 {
3570 /* Template template parameters need this. */
3575 }
3578 }
3580 /* Process information from new template parameter PARM and append it
3581 to the LIST being built. This new parameter is a non-type
3582 parameter iff IS_NON_TYPE is true. This new parameter is a
3583 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3584 is in PARM_LOC. NUM_TEMPLATE_PARMS is the size of the template
3585 parameter list PARM belongs to. This is used used to create a
3586 proper canonical type for the type of PARM that is to be created,
3587 iff PARM is a type. If the size is not known, this parameter shall
3588 be set to 0. */
3590 tree
3593 {
3595 tree defval;
3596 tree err_parm_list;
3603 {
3607 {
3611 else
3613 }
3616 }
3617 else
3621 {
3627 {
3631 }
3632 else
3633 {
3634 /* [temp.param]
3636 The top-level cv-qualifiers on the template-parameter are
3637 ignored when determining its type. */
3640 {
3644 }
3647 {
3648 /* This template parameter is not a parameter pack, but it
3649 should be. Complain about "bare" parameter packs. */
3652 /* Recover by calling this a parameter pack. */
3654 }
3655 }
3657 /* A template parameter is not modifiable. */
3666 processing_template_decl,
3671 }
3672 else
3673 {
3674 tree t;
3678 {
3680 /* This is for distinguishing between real templates and template
3681 template parameters */
3685 }
3686 else
3687 {
3689 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3692 }
3699 processing_template_decl,
3703 }
3709 }
3711 /* The end of a template parameter list has been reached. Process the
3712 tree list into a parameter vector, converting each parameter into a more
3713 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3714 as PARM_DECLs. */
3716 tree
3718 {
3723 current_template_parms
3728 {
3732 }
3737 }
3739 /* end_template_decl is called after a template declaration is seen. */
3741 void
3743 {
3749 /* This matches the pushlevel in begin_template_parm_list. */
3754 }
3756 /* Takes a TREE_LIST representing a template parameter and convert it
3757 into an argument suitable to be passed to the type substitution
3758 functions. Note that If the TREE_LIST contains an error_mark
3759 node, the returned argument is error_mark_node. */
3761 static tree
3763 {
3776 {
3780 {
3781 /* Turn this argument into a TYPE_ARGUMENT_PACK
3782 with a single element, which expands T. */
3784 #ifdef ENABLE_CHECKING
3785 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3787 #endif
3792 }
3793 }
3794 else
3795 {
3799 {
3800 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3801 with a single element, which expands T. */
3804 #ifdef ENABLE_CHECKING
3805 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3807 #endif
3813 }
3814 }
3816 }
3818 /* Given a set of template parameters, return them as a set of template
3819 arguments. The template parameters are represented as a TREE_VEC, in
3820 the form documented in cp-tree.h for template arguments. */
3822 static tree
3824 {
3825 tree header;
3830 /* If there is only one level of template parameters, we do not
3831 create a TREE_VEC of TREE_VECs. Instead, we return a single
3832 TREE_VEC containing the arguments. */
3837 {
3845 #ifdef ENABLE_CHECKING
3847 #endif
3851 else
3853 }
3856 /* This can happen for template parms of a template template
3857 parameter, e.g:
3859 template<template<class T, class U> class TT> struct S;
3861 Consider the level of the parms of TT; T and U both have
3862 level 2; TT has no template parm of level 1. So in this case
3863 the first element of full_template_args is NULL_TREE. If we
3864 leave it like this TMPL_ARG_DEPTH on args returns 1 instead
3865 of 2. This will make tsubst wrongly consider that T and U
3866 have level 1. Instead, let's create a dummy vector as the
3867 first element of full_template_args so that TMPL_ARG_DEPTH
3868 returns the correct depth for args. */
3871 }
3873 /* Within the declaration of a template, return the currently active
3874 template parameters as an argument TREE_VEC. */
3876 static tree
3878 {
3880 }
3882 /* Update the declared TYPE by doing any lookups which were thought to be
3883 dependent, but are not now that we know the SCOPE of the declarator. */
3885 tree
3887 {
3898 /* Don't bother building up the args in this case. */
3900 {
3901 /* tsubst in the args corresponding to the template parameters,
3902 including auto if present. Most things will be unchanged, but
3903 make_typename_type and tsubst_qualified_id will resolve
3904 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
3907 tree pushed;
3909 {
3913 }
3918 }
3924 {
3927 else
3929 }
3931 }
3933 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
3934 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
3935 a member template. Used by push_template_decl below. */
3937 static tree
3939 {
3947 }
3949 struct template_parm_data
3950 {
3951 /* The level of the template parameters we are currently
3952 processing. */
3955 /* The index of the specialization argument we are currently
3956 processing. */
3959 /* An array whose size is the number of template parameters. The
3960 elements are nonzero if the parameter has been used in any one
3961 of the arguments processed so far. */
3964 /* An array whose size is the number of template arguments. The
3965 elements are nonzero if the argument makes use of template
3966 parameters of this level. */
3968 };
3970 /* Subroutine of push_template_decl used to see if each template
3971 parameter in a partial specialization is used in the explicit
3972 argument list. If T is of the LEVEL given in DATA (which is
3973 treated as a template_parm_data*), then DATA->PARMS is marked
3974 appropriately. */
3976 static int
3978 {
3984 {
3987 }
3988 else
3989 {
3992 }
3995 {
3998 }
4000 /* Return zero so that for_each_template_parm will continue the
4001 traversal of the tree; we want to mark *every* template parm. */
4003 }
4005 /* Process the partial specialization DECL. */
4007 static tree
4009 {
4015 tree inner_parms;
4016 tree inst;
4029 /* We check that each of the template parameters given in the
4030 partial specialization is used in the argument list to the
4031 specialization. For example:
4033 template <class T> struct S;
4034 template <class T> struct S<T*>;
4036 The second declaration is OK because `T*' uses the template
4037 parameter T, whereas
4039 template <class T> struct S<int>;
4041 is no good. Even trickier is:
4043 template <class T>
4044 struct S1
4045 {
4046 template <class U>
4047 struct S2;
4048 template <class U>
4049 struct S2<T>;
4050 };
4052 The S2<T> declaration is actually invalid; it is a
4053 full-specialization. Of course,
4055 template <class U>
4056 struct S2<T (*)(U)>;
4058 or some such would have been OK. */
4066 {
4071 NULL,
4073 }
4076 {
4077 /* One of the template parms was not used in the
4078 specialization. */
4080 {
4083 }
4086 }
4091 /* [temp.class.spec]
4093 The argument list of the specialization shall not be identical to
4094 the implicit argument list of the primary template. */
4101 /* A partial specialization that replaces multiple parameters of the
4102 primary template with a pack expansion is less specialized for those
4103 parameters. */
4105 {
4107 "primary template because it replaces multiple parameters "
4111 }
4113 /* [temp.class.spec]
4115 A partially specialized non-type argument expression shall not
4116 involve template parameters of the partial specialization except
4117 when the argument expression is a simple identifier.
4119 The type of a template parameter corresponding to a specialized
4120 non-type argument shall not be dependent on a parameter of the
4121 specialization.
4123 Also, we verify that pack expansions only occur at the
4124 end of the argument list. */
4128 {
4135 {
4136 /* Extract the arguments from the argument pack. We'll be
4137 iterating over these in the following loop. */
4140 }
4143 {
4145 /* Get the Jth argument in the parameter pack. */
4149 {
4150 /* Pack expansions must come at the end of the
4151 argument list. */
4154 {
4158 else
4161 }
4162 }
4165 /* We only care about the pattern. */
4171 /* This next line is the `argument expression is not just a
4172 simple identifier' condition and also the `specialized
4173 non-type argument' bit. */
4175 {
4179 arg);
4180 else
4181 {
4182 /* Look at the corresponding template parameter,
4183 marking which template parameters its type depends
4184 upon. */
4188 {
4189 /* We haven't yet initialized TPD2. Do so now. */
4191 /* The number of parameters here is the number in the
4192 main template, which, as checked in the assertion
4193 above, is NARGS. */
4197 }
4199 /* Mark the template parameters. But this time, we're
4200 looking for the template parameters of the main
4201 template, not in the specialization. */
4208 NULL,
4212 {
4213 /* The type depended on some template parameters.
4214 If they are fully specialized in the
4215 specialization, that's OK. */
4224 "type %qT of template argument %qE depends "
4226 "type %qT of template argument %qE depends "
4228 type,
4229 arg);
4230 }
4231 }
4232 }
4233 }
4234 }
4236 /* We should only get here once. */
4246 {
4250 {
4254 "partial specialization of %qT after instantiation "
4256 }
4257 }
4260 }
4262 /* Check that a template declaration's use of default arguments and
4263 parameter packs is not invalid. Here, PARMS are the template
4264 parameters. IS_PRIMARY is true if DECL is the thing declared by
4265 a primary template. IS_PARTIAL is true if DECL is a partial
4266 specialization.
4268 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4269 declaration (but not a definition); 1 indicates a declaration, 2
4270 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4271 emitted for extraneous default arguments.
4273 Returns TRUE if there were no errors found, FALSE otherwise. */
4275 bool
4278 {
4281 tree parm_level;
4284 /* [temp.param]
4286 A default template-argument shall not be specified in a
4287 function template declaration or a function template definition, nor
4288 in the template-parameter-list of the definition of a member of a
4289 class template. */
4292 /* You can't have a function template declaration in a local
4293 scope, nor you can you define a member of a class template in a
4294 local scope. */
4301 /* If this is either a friend defined in the scope of the class
4302 or a member function. */
4308 /* And, if it was a member function, it really was defined in
4309 the scope of the class. */
4312 /* We already checked these parameters when the template was
4313 declared, so there's no need to do it again now. This function
4314 was defined in class scope, but we're processing it's body now
4315 that the class is complete. */
4318 /* Core issue 226 (C++0x only): the following only applies to class
4319 templates. */
4322 {
4323 /* [temp.param]
4325 If a template-parameter has a default template-argument, all
4326 subsequent template-parameters shall have a default
4327 template-argument supplied. */
4329 {
4336 {
4346 {
4348 /* For better subsequent error-recovery, we indicate that
4349 there should have been a default argument. */
4352 }
4354 && !is_friend_decl
4355 /* Don't complain about an enclosing partial
4356 specialization. */
4361 {
4362 /* A primary class template can only have one
4363 parameter pack, at the end of the template
4364 parameter list. */
4369 else
4377 }
4378 }
4379 }
4380 }
4383 || is_partial
4384 || !is_primary
4386 /* For an ordinary class template, default template arguments are
4387 allowed at the innermost level, e.g.:
4388 template <class T = int>
4389 struct S {};
4390 but, in a partial specialization, they're not allowed even
4391 there, as we have in [temp.class.spec]:
4393 The template parameter list of a specialization shall not
4394 contain default template argument values.
4396 So, for a partial specialization, or for a function template
4397 (in C++98/C++03), we look at all of them. */
4398 ;
4399 else
4400 /* But, for a primary class template that is not a partial
4401 specialization we look at all template parameters except the
4402 innermost ones. */
4405 /* Figure out what error message to issue. */
4418 else
4422 /* If we're inside a class definition, there's no need to
4423 examine the parameters to the class itself. On the one
4424 hand, they will be checked when the class is defined, and,
4425 on the other, default arguments are valid in things like:
4426 template <class T = double>
4427 struct S { template <class U> void f(U); };
4428 Here the default argument for `S' has no bearing on the
4429 declaration of `f'. */
4431 else
4432 /* Check everything. */
4438 {
4445 {
4450 {
4452 {
4459 }
4461 /* Clear out the default argument so that we are not
4462 confused later. */
4464 }
4465 }
4467 /* At this point, if we're still interested in issuing messages,
4468 they must apply to classes surrounding the object declared. */
4472 }
4475 }
4477 /* Worker for push_template_decl_real, called via
4478 for_each_template_parm. DATA is really an int, indicating the
4479 level of the parameters we are interested in. If T is a template
4480 parameter of that level, return nonzero. */
4482 static int
4484 {
4490 else
4493 }
4495 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
4496 parameters given by current_template_args, or reuses a
4497 previously existing one, if appropriate. Returns the DECL, or an
4498 equivalent one, if it is replaced via a call to duplicate_decls.
4500 If IS_FRIEND is true, DECL is a friend declaration. */
4502 tree
4504 {
4505 tree tmpl;
4506 tree args;
4507 tree info;
4508 tree ctx;
4512 /* True if the template is a member template, in the sense of
4513 [temp.mem]. */
4519 /* See if this is a partial specialization. */
4528 /* For a friend, we want the context of the friend function, not
4529 the type of which it is a friend. */
4533 /* In the case of a virtual function, we want the class in which
4534 it is defined. */
4536 else
4537 /* Otherwise, if we're currently defining some class, the DECL
4538 is assumed to be a member of the class. */
4547 /* See if this is a primary template. */
4549 /* A friend template that specifies a class context, i.e.
4550 template <typename T> friend void A<T>::f();
4551 is not primary. */
4553 else
4557 {
4562 {
4565 }
4567 {
4569 {
4570 /* [temp.mem]
4572 A destructor shall not be a member template. */
4575 }
4582 {
4583 /* [basic.stc.dynamic.allocation]
4585 An allocation function can be a function
4586 template. ... Template allocation functions shall
4587 have two or more parameters. */
4590 }
4591 }
4597 /* alias-declaration */
4599 else
4600 {
4603 }
4604 }
4606 /* Check to see that the rules regarding the use of default
4607 arguments are not being violated. */
4611 /* Ensure that there are no parameter packs in the type of this
4612 declaration that have not been expanded. */
4614 {
4615 /* Check each of the arguments individually to see if there are
4616 any bare parameter packs. */
4622 {
4625 {
4626 /* This is a PARM_DECL that contains unexpanded parameter
4627 packs. We have already complained about this in the
4628 check_for_bare_parameter_packs call, so just replace
4629 these types with ERROR_MARK_NODE. */
4632 }
4636 }
4638 /* Check for bare parameter packs in the return type and the
4639 exception specifiers. */
4641 /* Errors were already issued, set return type to int
4642 as the frontend doesn't expect error_mark_node as
4643 the return type. */
4647 }
4652 {
4655 }
4666 {
4671 /* If DECL is a TYPE_DECL for a class-template, then there won't
4672 be DECL_LANG_SPECIFIC. The information equivalent to
4673 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
4677 {
4678 /* Since a template declaration already existed for this
4679 class-type, we must be redeclaring it here. Make sure
4680 that the redeclaration is valid. */
4682 current_template_parms);
4683 /* We don't need to create a new TEMPLATE_DECL; just use the
4684 one we already had. */
4686 }
4687 else
4688 {
4690 member_template_p);
4695 {
4696 /* A specialization of a member template of a template
4697 class. */
4701 }
4702 }
4703 }
4704 else
4705 {
4711 {
4714 }
4722 {
4723 tree new_tmpl;
4725 /* The declaration is a specialization of a member
4726 template, declared outside the class. Therefore, the
4727 innermost template arguments will be NULL, so we
4728 replace them with the arguments determined by the
4729 earlier call to check_explicit_specialization. */
4732 new_tmpl
4734 member_template_p);
4744 args,
4747 }
4749 /* Make sure the template headers we got make sense. */
4754 {
4757 }
4758 else
4760 {
4765 {
4769 else
4774 }
4779 /* Can happen in erroneous input. */
4781 else
4785 }
4787 /* Check that the parms are used in the appropriate qualifying scopes
4788 in the declarator. */
4792 {
4798 /* Avoid crash in import_export_decl. */
4801 }
4802 }
4807 /* Push template declarations for global functions and types. Note
4808 that we do not try to push a global template friend declared in a
4809 template class; such a thing may well depend on the template
4810 parameters of the class. */
4813 {
4818 /* Hide template friend classes that haven't been declared yet. */
4820 {
4823 }
4824 }
4827 {
4833 {
4836 /* It is a conversion operator. See if the type converted to
4837 depends on innermost template operands. */
4840 depth))
4842 }
4844 /* Give template template parms a DECL_CONTEXT of the template
4845 for which they are a parameter. */
4848 {
4852 }
4853 }
4855 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
4856 back to its most general template. If TMPL is a specialization,
4857 ARGS may only have the innermost set of arguments. Add the missing
4858 argument levels if necessary. */
4866 else
4867 {
4872 }
4875 }
4877 tree
4879 {
4881 }
4883 /* FN is an inheriting constructor that inherits from the constructor
4884 template INHERITED; turn FN into a constructor template with a matching
4885 template header. */
4887 tree
4889 {
4890 tree inner_parms
4893 tree parms
4904 }
4906 /* Called when a class template TYPE is redeclared with the indicated
4907 template PARMS, e.g.:
4909 template <class T> struct S;
4910 template <class T> struct S {}; */
4912 bool
4914 {
4915 tree tmpl;
4916 tree tmpl_parms;
4920 {
4923 }
4927 /* The type is nested in some template class. Nothing to worry
4928 about here; there are no new template parameters for the nested
4929 type. */
4933 {
4935 tmpl);
4937 }
4943 {
4953 }
4956 {
4957 tree tmpl_parm;
4958 tree parm;
4959 tree tmpl_default;
4960 tree parm_default;
4974 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
4975 TEMPLATE_DECL. */
4985 {
4989 }
4992 {
4993 /* We have in [temp.param]:
4995 A template-parameter may not be given default arguments
4996 by two different declarations in the same scope. */
5001 }
5004 /* Update the previous template parameters (which are the ones
5005 that will really count) with the new default value. */
5008 /* Update the new parameters, too; they'll be used as the
5009 parameters for any members. */
5011 }
5014 }
5016 /* Simplify EXPR if it is a non-dependent expression. Returns the
5017 (possibly simplified) expression. */
5019 tree
5021 {
5025 /* If we're in a template, but EXPR isn't value dependent, simplify
5026 it. We're supposed to treat:
5028 template <typename T> void f(T[1 + 1]);
5029 template <typename T> void f(T[2]);
5031 as two declarations of the same function, for example. */
5036 {
5037 HOST_WIDE_INT saved_processing_template_decl;
5043 complain,
5048 }
5050 }
5052 tree
5054 {
5056 }
5058 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5059 template declaration, or a TYPE_DECL for an alias declaration. */
5061 bool
5063 {
5071 }
5073 /* Return TRUE iff is a specialization of an alias template. */
5075 bool
5077 {
5085 }
5087 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5088 must be a function or a pointer-to-function type, as specified
5089 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5090 and check that the resulting function has external linkage. */
5092 static tree
5094 {
5097 linkage_kind linkage;
5109 /* [temp.arg.nontype]/1
5111 A template-argument for a non-type, non-template template-parameter
5112 shall be one of:
5113 [...]
5114 -- the address of an object or function with external [C++11: or
5115 internal] linkage. */
5118 {
5122 else
5125 }
5129 {
5134 else
5139 }
5142 }
5144 /* Subroutine of convert_nontype_argument.
5145 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5146 Emit an error otherwise. */
5148 static bool
5150 tsubst_flags_t complain)
5151 {
5158 {
5162 }
5164 }
5166 /* Returns TRUE iff the address of OP is value-dependent.
5168 14.6.2.4 [temp.dep.temp]:
5169 A non-integral non-type template-argument is dependent if its type is
5170 dependent or it has either of the following forms
5171 qualified-id
5172 & qualified-id
5173 and contains a nested-name-specifier which specifies a class-name that
5174 names a dependent type.
5176 We generalize this to just say that the address of a member of a
5177 dependent class is value-dependent; the above doesn't cover the
5178 address of a static data member named with an unqualified-id. */
5180 static bool
5182 {
5183 /* We could use get_inner_reference here, but there's no need;
5184 this is only relevant for template non-type arguments, which
5185 can only be expressed as &id-expression. */
5187 {
5191 }
5194 }
5196 /* The next set of functions are used for providing helpful explanatory
5197 diagnostics for failed overload resolution. Their messages should be
5198 indented by two spaces for consistency with the messages in
5199 call.c */
5201 static int
5203 {
5205 }
5207 static int
5209 {
5214 }
5216 static int
5218 {
5220 }
5222 static int
5224 {
5230 }
5232 static int
5234 {
5238 }
5240 static int
5242 {
5245 " template parameter %qD is not a parameter pack, but "
5249 }
5251 static int
5253 {
5256 " template argument %qE does not match "
5260 }
5262 static int
5264 {
5268 }
5270 static int
5272 {
5278 }
5280 static int
5282 {
5284 {
5289 else
5291 " deduced conflicting values for non-type parameter "
5293 }
5295 }
5297 static int
5299 {
5302 " variable-sized array type %qT is not "
5304 arg);
5306 }
5308 static int
5310 {
5314 arg);
5316 }
5318 static int
5320 {
5327 }
5329 static int
5331 {
5333 }
5335 static int
5337 {
5339 }
5341 static int
5344 {
5349 }
5351 static int
5354 {
5357 {
5365 }
5367 }
5369 static int
5371 {
5374 " template parameters of a template template argument are "
5377 }
5379 static int
5381 {
5387 }
5389 static int
5391 {
5396 }
5398 static int
5400 {
5404 arg);
5406 }
5408 /* Attempt to convert the non-type template parameter EXPR to the
5409 indicated TYPE. If the conversion is successful, return the
5410 converted value. If the conversion is unsuccessful, return
5411 NULL_TREE if we issued an error message, or error_mark_node if we
5412 did not. We issue error messages for out-and-out bad template
5413 parameters, but not simply because the conversion failed, since we
5414 might be just trying to do argument deduction. Both TYPE and EXPR
5415 must be non-dependent.
5417 The conversion follows the special rules described in
5418 [temp.arg.nontype], and it is much more strict than an implicit
5419 conversion.
5421 This function is called twice for each template argument (see
5422 lookup_template_class for a more accurate description of this
5423 problem). This means that we need to handle expressions which
5424 are not valid in a C++ source, but can be created from the
5425 first call (for instance, casts to perform conversions). These
5426 hacks can go away after we fix the double coercion problem. */
5428 static tree
5430 {
5431 tree expr_type;
5433 /* Detect immediately string literals as invalid non-type argument.
5434 This special-case is not needed for correctness (we would easily
5435 catch this later), but only to provide better diagnostic for this
5436 common user mistake. As suggested by DR 100, we do not mention
5437 linkage issues in the diagnostic as this is not the point. */
5438 /* FIXME we're making this OK. */
5440 {
5446 }
5448 /* Add the ADDR_EXPR now for the benefit of
5449 value_dependent_expression_p. */
5452 {
5456 }
5458 /* If we are in a template, EXPR may be non-dependent, but still
5459 have a syntactic, rather than semantic, form. For example, EXPR
5460 might be a SCOPE_REF, rather than the VAR_DECL to which the
5461 SCOPE_REF refers. Preserving the qualifying scope is necessary
5462 so that access checking can be performed when the template is
5463 instantiated -- but here we need the resolved form so that we can
5464 convert the argument. */
5475 else
5478 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
5479 to a non-type argument of "nullptr". */
5483 /* In C++11, integral or enumeration non-type template arguments can be
5484 arbitrary constant expressions. Pointer and pointer to
5485 member arguments can be general constant expressions that evaluate
5486 to a null value, but otherwise still need to be of a specific form. */
5488 {
5490 /* A PTRMEM_CST is already constant, and a valid template
5491 argument for a parameter of pointer to member type, we just want
5492 to leave it in that form rather than lower it to a
5497 {
5502 }
5503 }
5505 /* HACK: Due to double coercion, we can get a
5506 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5507 which is the tree that we built on the first call (see
5508 below when coercing to reference to object or to reference to
5509 function). We just strip everything and get to the arg.
5510 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5511 for examples. */
5513 {
5519 {
5520 /* ??? Maybe we could use convert_from_reference here, but we
5521 would need to relax its constraints because the NOP_EXPR
5522 could actually change the type to something more cv-qualified,
5523 and this is not folded by convert_from_reference. */
5528 && (same_type_ignoring_top_level_qualifiers_p
5531 {
5534 }
5535 }
5536 }
5538 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5539 parameter is a pointer to object, through decay and
5540 qualification conversion. Let's strip everything. */
5542 {
5546 /* Skip the ADDR_EXPR only if it is part of the decay for
5547 an array. Otherwise, it is part of the original argument
5548 in the source code. */
5552 }
5554 /* [temp.arg.nontype]/5, bullet 1
5556 For a non-type template-parameter of integral or enumeration type,
5557 integral promotions (_conv.prom_) and integral conversions
5558 (_conv.integral_) are applied. */
5560 {
5569 /* Notice that there are constant expressions like '4 % 0' which
5570 do not fold into integer constants. */
5572 {
5574 {
5585 /* else cxx_constant_value complained but gave us
5586 a real constant, so go ahead. */
5588 }
5589 else
5591 }
5592 }
5593 /* [temp.arg.nontype]/5, bullet 2
5595 For a non-type template-parameter of type pointer to object,
5596 qualification conversions (_conv.qual_) and the array-to-pointer
5597 conversion (_conv.array_) are applied. */
5599 {
5600 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
5602 A template-argument for a non-type, non-template template-parameter
5603 shall be one of: [...]
5605 -- the name of a non-type template-parameter;
5606 -- the address of an object or function with external linkage, [...]
5607 expressed as "& id-expression" where the & is optional if the name
5608 refers to a function or array, or if the corresponding
5609 template-parameter is a reference.
5611 Here, we do not care about functions, as they are invalid anyway
5612 for a parameter of type pointer-to-object. */
5615 /* Non-type template parameters are OK. */
5616 ;
5621 {
5623 {
5625 "because %qD is a variable, not the address of "
5629 }
5630 /* Other values, like integer constants, might be valid
5631 non-type arguments of some other type. */
5633 }
5634 else
5635 {
5636 tree decl;
5641 {
5646 }
5648 {
5653 }
5655 {
5660 }
5661 }
5670 }
5671 /* [temp.arg.nontype]/5, bullet 3
5673 For a non-type template-parameter of type reference to object, no
5674 conversions apply. The type referred to by the reference may be more
5675 cv-qualified than the (otherwise identical) type of the
5676 template-argument. The template-parameter is bound directly to the
5677 template-argument, which must be an lvalue. */
5679 {
5681 expr_type))
5685 {
5689 }
5692 {
5696 }
5698 /* [temp.arg.nontype]/1
5700 A template-argument for a non-type, non-template template-parameter
5701 shall be one of: [...]
5703 -- the address of an object or function with external linkage. */
5706 {
5709 {
5711 "because a reference variable does not have a constant "
5714 }
5715 }
5718 {
5723 }
5726 {
5731 }
5734 }
5735 /* [temp.arg.nontype]/5, bullet 4
5737 For a non-type template-parameter of type pointer to function, only
5738 the function-to-pointer conversion (_conv.func_) is applied. If the
5739 template-argument represents a set of overloaded functions (or a
5740 pointer to such), the matching function is selected from the set
5741 (_over.over_). */
5743 {
5744 /* If the argument is a template-id, we might not have enough
5745 context information to decay the pointer. */
5747 {
5751 }
5754 /* Null pointer values are OK in C++11. */
5760 }
5761 /* [temp.arg.nontype]/5, bullet 5
5763 For a non-type template-parameter of type reference to function, no
5764 conversions apply. If the template-argument represents a set of
5765 overloaded functions, the matching function is selected from the set
5766 (_over.over_). */
5768 {
5770 {
5775 }
5782 }
5783 /* [temp.arg.nontype]/5, bullet 6
5785 For a non-type template-parameter of type pointer to member function,
5786 no conversions apply. If the template-argument represents a set of
5787 overloaded member functions, the matching member function is selected
5788 from the set (_over.over_). */
5790 {
5795 /* [temp.arg.nontype] bullet 1 says the pointer to member
5796 expression must be a pointer-to-member constant. */
5800 /* There is no way to disable standard conversions in
5801 resolve_address_of_overloaded_function (called by
5802 instantiate_type). It is possible that the call succeeded by
5803 converting &B::I to &D::I (where B is a base of D), so we need
5804 to reject this conversion here.
5806 Actually, even if there was a way to disable standard conversions,
5807 it would still be better to reject them here so that we can
5808 provide a superior diagnostic. */
5810 {
5814 /* If we are just one standard conversion off, explain. */
5819 }
5820 }
5821 /* [temp.arg.nontype]/5, bullet 7
5823 For a non-type template-parameter of type pointer to data member,
5824 qualification conversions (_conv.qual_) are applied. */
5826 {
5827 /* [temp.arg.nontype] bullet 1 says the pointer to member
5828 expression must be a pointer-to-member constant. */
5835 }
5837 {
5839 {
5843 }
5845 }
5846 /* A template non-type parameter must be one of the above. */
5847 else
5850 /* Sanity check: did we actually convert the argument to the
5851 right type? */
5855 }
5857 /* Subroutine of coerce_template_template_parms, which returns 1 if
5858 PARM_PARM and ARG_PARM match using the rule for the template
5859 parameters of template template parameters. Both PARM and ARG are
5860 template parameters; the rest of the arguments are the same as for
5861 coerce_template_template_parms.
5862 */
5863 static int
5865 tree arg,
5866 tsubst_flags_t complain,
5867 tree in_decl,
5868 tree outer_args)
5869 {
5878 {
5880 /* We encounter instantiations of templates like
5881 template <template <template <class> class> class TT>
5882 class C; */
5883 {
5890 }
5891 /* Fall through. */
5896 /* Argument is a parameter pack but parameter is not. */
5901 /* The tsubst call is used to handle cases such as
5903 template <int> class C {};
5904 template <class T, template <T> class TT> class D {};
5905 D<int, C> d;
5907 i.e. the parameter list of TT depends on earlier parameters. */
5909 && !same_type_p
5916 /* Argument is a parameter pack but parameter is not. */
5923 }
5926 }
5929 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
5930 template template parameters. Both PARM_PARMS and ARG_PARMS are
5931 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
5932 or PARM_DECL.
5934 Consider the example:
5935 template <class T> class A;
5936 template<template <class U> class TT> class B;
5938 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
5939 the parameters to A, and OUTER_ARGS contains A. */
5941 static int
5943 tree arg_parms,
5944 tsubst_flags_t complain,
5945 tree in_decl,
5946 tree outer_args)
5947 {
5958 /* Determine whether we have a parameter pack at the end of the
5959 template template parameter's template parameter list. */
5961 {
5968 {
5982 }
5983 }
5989 /* Check all of the template parameters except the parameter pack at
5990 the end (if any). */
5992 {
6001 outer_args))
6004 }
6007 {
6008 /* Check each of the template parameters in the template
6009 argument against the template parameter pack at the end of
6010 the template template parameter. */
6017 {
6024 outer_args))
6026 }
6027 }
6030 }
6032 /* Verifies that the deduced template arguments (in TARGS) for the
6033 template template parameters (in TPARMS) represent valid bindings,
6034 by comparing the template parameter list of each template argument
6035 to the template parameter list of its corresponding template
6036 template parameter, in accordance with DR150. This
6037 routine can only be called after all template arguments have been
6038 deduced. It will return TRUE if all of the template template
6039 parameter bindings are okay, FALSE otherwise. */
6040 bool
6042 {
6046 /* We're dealing with template parms in this process. */
6052 {
6057 {
6062 {
6063 /* Look inside the argument pack. */
6066 }
6069 {
6073 /* Extract the next argument from the argument
6074 pack. */
6078 /* Look at the pattern of the pack expansion. */
6081 /* Extract the template parameters from the template
6082 argument. */
6088 /* Verify that we can coerce the template template
6089 parameters from the template argument to the template
6090 parameter. This requires an exact match. */
6092 && !coerce_template_template_parms
6094 targ_parms,
6095 tf_none,
6096 tparm,
6097 targs))
6098 {
6101 }
6102 }
6103 }
6104 }
6106 out:
6110 }
6112 /* Since type attributes aren't mangled, we need to strip them from
6113 template type arguments. */
6115 static tree
6117 {
6118 tree mv;
6125 {
6130 }
6132 }
6134 /* Convert the indicated template ARG as necessary to match the
6135 indicated template PARM. Returns the converted ARG, or
6136 error_mark_node if the conversion was unsuccessful. Error and
6137 warning messages are issued under control of COMPLAIN. This
6138 conversion is for the Ith parameter in the parameter list. ARGS is
6139 the full set of template arguments deduced so far. */
6141 static tree
6143 tree arg,
6144 tree args,
6145 tsubst_flags_t complain,
6147 tree in_decl)
6148 {
6149 tree orig_arg;
6150 tree val;
6155 {
6156 /* The template argument was the name of some
6157 member function. That's usually
6158 invalid, but static members are OK. In any
6159 case, grab the underlying fields/functions
6160 and issue an error later if required. */
6163 }
6171 /* When determining whether an argument pack expansion is a template,
6172 look at the pattern. */
6176 /* Deal with an injected-class-name used as a template template arg. */
6178 {
6181 {
6191 }
6192 }
6194 is_tmpl_type =
6210 {
6212 {
6216 }
6219 "to refer to a type member of a template parameter, "
6224 typename_type,
6225 complain);
6228 }
6230 {
6232 {
6234 {
6244 else
6246 }
6247 }
6249 }
6251 {
6253 {
6259 else
6261 }
6263 }
6266 {
6268 {
6272 /* The number of argument required is not known yet.
6273 Just accept it for now. */
6275 else
6276 {
6278 tree argparm;
6284 args))
6285 {
6288 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6289 TEMPLATE_DECL. */
6291 {
6296 }
6297 }
6298 else
6299 {
6301 {
6307 }
6310 }
6311 }
6312 }
6313 else
6315 /* We only form one instance of each template specialization.
6316 Therefore, if we use a non-canonical variant (i.e., a
6317 typedef), any future messages referring to the type will use
6318 the typedef, which is confusing if those future uses do not
6319 themselves also use the typedef. */
6322 }
6323 else
6324 {
6331 {
6334 else
6335 {
6336 /* Not sure if this is reachable, but it doesn't hurt
6337 to be robust. */
6340 }
6341 }
6343 /* We used to call digest_init here. However, digest_init
6344 will report errors, which we don't want when complain
6345 is zero. More importantly, digest_init will try too
6346 hard to convert things: for example, `0' should not be
6347 converted to pointer type at this point according to
6348 the standard. Accepting this is not merely an
6349 extension, since deciding whether or not these
6350 conversions can occur is part of determining which
6351 function template to call, or whether a given explicit
6352 argument specification is valid. */
6354 else
6363 {
6364 /* Strip typedefs from the SCOPE_REF. */
6367 complain);
6370 }
6371 }
6374 }
6376 /* Coerces the remaining template arguments in INNER_ARGS (from
6377 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6378 Returns the coerced argument pack. PARM_IDX is the position of this
6379 parameter in the template parameter list. ARGS is the original
6380 template argument list. */
6381 static tree
6384 tree args,
6385 tree inner_args,
6387 tree new_args,
6389 tree in_decl,
6390 tsubst_flags_t complain)
6391 {
6394 tree packed_args;
6395 tree argument_pack;
6405 {
6406 /* When the template parameter is a non-type template
6407 parameter pack whose type uses parameter packs, we need
6408 to look at each of the template arguments
6409 separately. Build a vector of the types for these
6410 non-type template parameters in PACKED_TYPES. */
6411 tree expansion
6419 /* Check that we have the right number of arguments. */
6423 {
6424 int needed_parms
6429 }
6431 /* If we aren't able to check the actual arguments now
6432 (because they haven't been expanded yet), we can at least
6433 verify that all of the types used for the non-type
6434 template parameter pack are, in fact, valid for non-type
6435 template parameters. */
6438 {
6441 {
6445 }
6446 }
6447 }
6449 /* Convert the remaining arguments, which will be a part of the
6450 parameter pack "parm". */
6452 {
6457 {
6458 /* When we have a vector of types (corresponding to the
6459 non-type template parameter pack that uses parameter
6460 packs in its type, as mention above), and the
6461 argument is not an expansion (which expands to a
6462 currently unknown number of arguments), clone the
6463 parm and give it the next type in PACKED_TYPES. */
6467 }
6470 {
6473 }
6474 else
6477 in_decl);
6481 }
6486 else
6487 {
6492 }
6495 #ifdef ENABLE_CHECKING
6498 #endif
6500 }
6502 /* Returns true if the template argument vector ARGS contains
6503 any pack expansions, false otherwise. */
6505 static bool
6507 {
6514 }
6516 /* Convert all template arguments to their appropriate types, and
6517 return a vector containing the innermost resulting template
6518 arguments. If any error occurs, return error_mark_node. Error and
6519 warning messages are issued under control of COMPLAIN.
6521 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6522 for arguments not specified in ARGS. Otherwise, if
6523 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
6524 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
6525 USE_DEFAULT_ARGS is false, then all arguments must be specified in
6526 ARGS. */
6528 static tree
6530 tree args,
6531 tree in_decl,
6532 tsubst_flags_t complain,
6535 {
6537 tree inner_args;
6538 tree new_args;
6539 tree new_inner_args;
6543 /* When used as a boolean value, indicates whether this is a
6544 variadic template parameter list. Since it's an int, we can also
6545 subtract it from nparms to get the number of non-variadic
6546 parameters. */
6555 /* Determine if there are any parameter packs. */
6557 {
6563 }
6566 /* If there are no parameters that follow a parameter pack, we need to
6567 expand any argument packs so that we can deduce a parameter pack from
6568 some non-packed args followed by an argument pack, as in variadic85.C.
6569 If there are such parameters, we need to leave argument packs intact
6570 so the arguments are assigned properly. This can happen when dealing
6571 with a nested class inside a partial specialization of a class
6572 template, as in variadic92.C, or when deducing a template parameter pack
6573 from a sub-declarator, as in variadic114.C. */
6580 && require_all_args
6582 && (!use_default_args
6585 {
6587 {
6589 {
6593 }
6594 else
6600 }
6603 }
6605 /* We need to evaluate the template arguments, even though this
6606 template-id may be nested within a "sizeof". */
6614 {
6615 tree arg;
6616 tree parm;
6618 /* Get the Ith template parameter. */
6622 {
6625 }
6627 /* Calculate the next argument. */
6630 else
6635 {
6636 /* All remaining arguments will be placed in the
6637 template parameter pack PARM. */
6643 /* Store this argument. */
6645 lost++;
6648 /* We are done with all of the arguments. */
6652 }
6654 {
6656 {
6657 /* We don't know how many args we have yet, just
6658 use the unconverted ones for now. */
6661 }
6662 }
6664 {
6665 /* There must be a default arg in this case. */
6668 /* The position of the first default template argument,
6669 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
6670 Record that. */
6673 }
6674 else
6678 {
6681 }
6683 /* This only occurs if there was an error in the template
6684 parameter list itself (which we would already have
6685 reported) that we are trying to recover from, e.g., a class
6686 template with a parameter list such as
6687 template<typename..., typename>. */
6689 else
6695 lost++;
6697 }
6704 #ifdef ENABLE_CHECKING
6708 #endif
6711 }
6713 /* Like coerce_template_parms. If PARMS represents all template
6714 parameters levels, this function returns a vector of vectors
6715 representing all the resulting argument levels. Note that in this
6716 case, only the innermost arguments are coerced because the
6717 outermost ones are supposed to have been coerced already.
6719 Otherwise, if PARMS represents only (the innermost) vector of
6720 parameters, this function returns a vector containing just the
6721 innermost resulting arguments. */
6723 static tree
6725 tree args,
6726 tree in_decl,
6727 tsubst_flags_t complain,
6730 {
6733 tree coerced_args;
6736 {
6738 tree level;
6744 {
6745 tree l;
6749 require_all_args,
6750 use_default_args);
6751 else
6758 }
6759 }
6760 else
6763 require_all_args,
6764 use_default_args);
6766 }
6768 /* Returns 1 if template args OT and NT are equivalent. */
6770 static int
6772 {
6779 /* For member templates */
6788 {
6805 }
6807 {
6808 /* We get here probably because we are in the middle of substituting
6809 into the pattern of a pack expansion. In that case the
6810 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
6811 interested in. So we want to use the initial pack argument for
6812 the comparison. */
6817 }
6822 else
6824 }
6826 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
6827 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
6828 NEWARG_PTR with the offending arguments if they are non-NULL. */
6830 static int
6833 {
6846 {
6851 {
6857 }
6858 }
6860 }
6862 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
6863 of template arguments. Returns 0 otherwise. */
6865 int
6867 {
6869 }
6871 static void
6873 {
6883 /* We are called both from instantiate_decl, where we've already had a
6884 tinst_level pushed, and instantiate_template, where we haven't.
6885 Compensate. */
6896 else
6905 }
6908 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
6909 ARGLIST. Valid choices for FNS are given in the cp-tree.def
6910 documentation for TEMPLATE_ID_EXPR. */
6912 tree
6914 {
6915 tree type;
6923 {
6926 }
6929 {
6931 unknown_type_node,
6933 arglist);
6935 }
6942 }
6944 /* Within the scope of a template class S<T>, the name S gets bound
6945 (in build_self_reference) to a TYPE_DECL for the class, not a
6946 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
6947 or one of its enclosing classes, and that type is a template,
6948 return the associated TEMPLATE_DECL. Otherwise, the original
6949 DECL is returned.
6951 Also handle the case when DECL is a TREE_LIST of ambiguous
6952 injected-class-names from different bases. */
6954 tree
6956 {
6960 /* DR 176: A lookup that finds an injected-class-name (10.2
6961 [class.member.lookup]) can result in an ambiguity in certain cases
6962 (for example, if it is found in more than one base class). If all of
6963 the injected-class-names that are found refer to specializations of
6964 the same class template, and if the name is followed by a
6965 template-argument-list, the reference refers to the class template
6966 itself and not a specialization thereof, and is not ambiguous. */
6968 {
6971 {
6977 }
6980 else
6982 }
6988 }
6990 /* Given an IDENTIFIER_NODE (type TEMPLATE_DECL) and a chain of
6991 parameters, find the desired type.
6993 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
6995 IN_DECL, if non-NULL, is the template declaration we are trying to
6996 instantiate.
6998 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
6999 the class we are looking up.
7001 Issue error and warning messages under control of COMPLAIN.
7003 If the template class is really a local class in a template
7004 function, then the FUNCTION_CONTEXT is the function in which it is
7005 being instantiated.
7007 ??? Note that this function is currently called *twice* for each
7008 template-id: the first time from the parser, while creating the
7009 incomplete type (finish_template_type), and the second type during the
7010 real instantiation (instantiate_template_class). This is surely something
7011 that we want to avoid. It also causes some problems with argument
7012 coercion (see convert_nontype_argument for more information on this). */
7014 static tree
7017 {
7019 tree t;
7022 spec_entry elt;
7023 hashval_t hash;
7026 {
7030 else
7031 {
7038 }
7041 }
7043 {
7046 /* If we are declaring a constructor, say A<T>::A<T>, we will get
7047 an implicit typename for the second A. Deal with it. */
7052 {
7055 }
7056 }
7059 {
7062 }
7066 {
7070 }
7072 /* Issue an error message if we didn't find a template. */
7074 {
7078 }
7081 /* Make sure it's a user visible template, if it was named by
7082 the user. */
7085 {
7087 {
7091 }
7093 }
7098 {
7099 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7100 template arguments */
7102 tree parm;
7103 tree arglist2;
7104 tree outer;
7108 /* Consider an example where a template template parameter declared as
7110 template <class T, class U = std::allocator<T> > class TT
7112 The template parameter level of T and U are one level larger than
7113 of TT. To proper process the default argument of U, say when an
7114 instantiation `TT<int>' is seen, we need to build the full
7115 arguments containing {int} as the innermost level. Outer levels,
7116 available when not appearing as default template argument, can be
7117 obtained from the arguments of the enclosing template.
7119 Suppose that TT is later substituted with std::vector. The above
7120 instantiation is `TT<int, std::allocator<T> >' with TT at
7121 level 1, and T at level 2, while the template arguments at level 1
7122 becomes {std::vector} and the inner level 2 is {int}. */
7128 /* This is an argument of the current template, so we haven't set
7129 DECL_CONTEXT yet. */
7136 complain,
7146 }
7147 else
7148 {
7150 tree gen_tmpl;
7151 tree type_decl;
7159 /* An error occured while building the template TEMPL, and a
7160 diagnostic has most certainly been emitted for that
7161 already. Let's propagate that error. */
7170 {
7171 /* We've been given an incomplete set of template arguments.
7172 For example, given:
7174 template <class T> struct S1 {
7175 template <class U> struct S2 {};
7176 template <class U> struct S2<U*> {};
7177 };
7179 we will be called with an ARGLIST of `U*', but the
7180 TEMPLATE will be `template <class T> template
7181 <class U> struct S1<T>::S2'. We must fill in the missing
7182 arguments. */
7183 arglist
7185 arglist);
7187 }
7189 /* Now we should have enough arguments. */
7192 /* From here on, we're only interested in the most general
7193 template. */
7195 /* Calculate the BOUND_ARGS. These will be the args that are
7196 actually tsubst'd into the definition to create the
7197 instantiation. */
7199 {
7200 /* We have multiple levels of arguments to coerce, at once. */
7210 {
7211 tree a;
7215 complain,
7218 else
7219 /* Outer levels should have already been coerced. */
7222 /* Don't process further if one of the levels fails. */
7224 {
7225 /* Restore the ARGLIST to its full size. */
7228 }
7232 /* We temporarily reduce the length of the ARGLIST so
7233 that coerce_template_parms will see only the arguments
7234 corresponding to the template parameters it is
7235 examining. */
7237 }
7239 /* Restore the ARGLIST to its full size. */
7243 }
7244 else
7245 arglist
7248 gen_tmpl,
7249 complain,
7254 /* We were unable to bind the arguments. */
7257 /* In the scope of a template class, explicit references to the
7258 template class refer to the type of the template, not any
7259 instantiation of it. For example, in:
7261 template <class T> class C { void f(C<T>); }
7263 the `C<T>' is just the same as `C'. Outside of the
7264 class, however, such a reference is an instantiation. */
7268 /* comp_template_args is expensive, check it last. */
7270 arglist))
7273 /* If we already have this specialization, return it. */
7285 /* If the deduced arguments are invalid, then the binding
7286 failed. */
7290 complain))
7297 {
7302 }
7312 /* Create the type. */
7314 {
7316 {
7322 }
7323 else
7324 {
7325 /* We don't want to call start_enum for this type, since
7326 the values for the enumeration constants may involve
7327 template parameters. And, no one should be interested
7328 in the enumeration constants for such a type. */
7331 }
7335 }
7337 {
7338 /* The user referred to a specialization of an alias
7339 template represented by GEN_TMPL.
7341 [temp.alias]/2 says:
7343 When a template-id refers to the specialization of an
7344 alias template, it is equivalent to the associated
7345 type obtained by substitution of its
7346 template-arguments for the template-parameters in the
7347 type-id of the alias template. */
7350 /* Note that the call above (by indirectly calling
7351 register_specialization in tsubst_decl) registers the
7352 TYPE_DECL representing the specialization of the alias
7353 template. So next time someone substitutes ARGLIST for
7354 the template parms into the alias template (GEN_TMPL),
7355 she'll get that TYPE_DECL back. */
7359 }
7361 {
7368 /* A local class. Make sure the decl gets registered properly. */
7373 /* This instantiation is another name for the primary
7374 template type. Set the TYPE_CANONICAL field
7375 appropriately. */
7378 /* Some of the template arguments require structural
7379 equality testing, so this template class requires
7380 structural equality testing. */
7382 }
7383 else
7386 /* If we called start_enum or pushtag above, this information
7387 will already be set up. */
7389 {
7396 }
7397 else
7401 {
7407 {
7410 }
7411 }
7413 /* Let's consider the explicit specialization of a member
7414 of a class template specialization that is implicitely instantiated,
7415 e.g.:
7416 template<class T>
7417 struct S
7418 {
7419 template<class U> struct M {}; //#0
7420 };
7422 template<>
7423 template<>
7424 struct S<int>::M<char> //#1
7425 {
7426 int i;
7427 };
7428 [temp.expl.spec]/4 says this is valid.
7430 In this case, when we write:
7431 S<int>::M<char> m;
7433 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
7434 the one of #0.
7436 When we encounter #1, we want to store the partial instantiation
7437 of M (template<class T> S<int>::M<T>) in it's CLASSTYPE_TI_TEMPLATE.
7439 For all cases other than this "explicit specialization of member of a
7440 class template", we just want to store the most general template into
7441 the CLASSTYPE_TI_TEMPLATE of M.
7443 This case of "explicit specialization of member of a class template"
7444 only happens when:
7445 1/ the enclosing class is an instantiation of, and therefore not
7446 the same as, the context of the most general template, and
7447 2/ we aren't looking at the partial instantiation itself, i.e.
7448 the innermost arguments are not the same as the innermost parms of
7449 the most general template.
7451 So it's only when 1/ and 2/ happens that we want to use the partial
7452 instantiation of the member template in lieu of its most general
7453 template. */
7457 /* the enclosing class must be an instantiation... */
7460 {
7461 tree partial_inst_args;
7464 partial_inst_args =
7470 use_partial_inst_tmpl =
7471 /*...and we must not be looking at the partial instantiation
7472 itself. */
7474 partial_inst_args);
7475 }
7478 /* This case is easy; there are no member templates involved. */
7480 else
7481 {
7482 /* This is a full instantiation of a member template. Find
7483 the partial instantiation of which this is an instance. */
7485 /* Temporarily reduce by one the number of levels in the ARGLIST
7486 so as to avoid comparing the last set of arguments. */
7490 /* FOUND is either a proper class type, or an alias
7491 template specialization. In the later case, it's a
7492 TYPE_DECL, resulting from the substituting of arguments
7493 for parameters in the TYPE_DECL of the alias template
7494 done earlier. So be careful while getting the template
7495 of FOUND. */
7499 }
7510 /* Note this use of the partial instantiation so we can check it
7511 later in maybe_process_partial_specialization. */
7517 /* Now that the type has been registered on the instantiations
7518 list, we set up the enumerators. Because the enumeration
7519 constants may involve the enumeration type itself, we make
7520 sure to register the type first, and then create the
7521 constants. That way, doing tsubst_expr for the enumeration
7522 constants won't result in recursive calls here; we'll find
7523 the instantiation and exit above. */
7527 /* If the type makes use of template parameters, the
7528 code that generates debugging information will crash. */
7531 /* Possibly limit visibility based on template args. */
7536 }
7537 }
7539 /* Wrapper for lookup_template_class_1. */
7541 tree
7544 {
7545 tree ret;
7551 }
7552 \f
7553 struct pair_fn_data
7554 {
7555 tree_fn_t fn;
7557 /* True when we should also visit template parameters that occur in
7558 non-deduced contexts. */
7561 };
7563 /* Called from for_each_template_parm via walk_tree. */
7565 static tree
7567 {
7580 {
7584 /* Fall through. */
7607 /* Since we're not going to walk subtrees, we have to do this
7608 explicitly here. */
7612 /* Fall through. */
7615 /* Check the return type. */
7620 /* Check the parameter types. Since default arguments are not
7621 instantiated until they are needed, the TYPE_ARG_TYPES may
7622 contain expressions that involve template parameters. But,
7623 no-one should be looking at them yet. And, once they're
7624 instantiated, they don't contain template parameters, so
7625 there's no point in looking at them then, either. */
7626 {
7627 tree parm;
7634 /* Since we've already handled the TYPE_ARG_TYPES, we don't
7635 want walk_tree walking into them itself. */
7637 }
7655 /* Fall through. */
7671 /* Record template parameters such as `T' inside `TT<T>'. */
7675 /* Fall through. */
7687 /* A template template parameter is encountered. */
7693 /* Already substituted template template parameter */
7716 /* If there's no type, then this thing must be some expression
7717 involving template parameters. */
7739 }
7741 /* We didn't find any template parameters we liked. */
7743 }
7745 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
7746 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
7747 call FN with the parameter and the DATA.
7748 If FN returns nonzero, the iteration is terminated, and
7749 for_each_template_parm returns 1. Otherwise, the iteration
7750 continues. If FN never returns a nonzero value, the value
7751 returned by for_each_template_parm is 0. If FN is NULL, it is
7752 considered to be the function which always returns 1.
7754 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
7755 parameters that occur in non-deduced contexts. When false, only
7756 visits those template parameters that can be deduced. */
7758 static int
7762 {
7766 /* Set up. */
7771 /* Walk the tree. (Conceptually, we would like to walk without
7772 duplicates, but for_each_template_parm_r recursively calls
7773 for_each_template_parm, so we would need to reorganize a fair
7774 bit to use walk_tree_without_duplicates, so we keep our own
7775 visited list.) */
7778 else
7781 for_each_template_parm_r,
7785 /* Clean up. */
7787 {
7790 }
7793 }
7795 /* Returns true if T depends on any template parameter. */
7797 int
7799 {
7826 else
7827 {
7830 }
7835 }
7837 /* Returns true iff current_function_decl is an incompletely instantiated
7838 template. Useful instead of processing_template_decl because the latter
7839 is set to 0 during fold_non_dependent_expr. */
7841 bool
7843 {
7852 }
7854 /* Returns true if T depends on any template parameter with level LEVEL. */
7856 int
7858 {
7861 }
7863 /* Returns TRUE iff INST is an instantiation we don't need to do in an
7864 ill-formed translation unit, i.e. a variable or function that isn't
7865 usable in a constant expression. */
7869 {
7873 }
7875 /* Returns TRUE iff we should refuse to instantiate DECL because it's
7876 neglectable and instantiated from within an erroneous instantiation. */
7878 static bool
7880 {
7891 }
7899 /* We're starting to instantiate D; record the template instantiation context
7900 for diagnostics and to restore it later. */
7902 int
7904 {
7908 {
7914 else
7922 }
7924 /* If the current instantiation caused problems, don't let it instantiate
7925 anything else. Do allow deduction substitution and decls usable in
7926 constant expressions. */
7943 }
7945 /* We're done instantiating this template; return to the instantiation
7946 context. */
7948 void
7950 {
7951 /* Restore the filename and line number stashed away when we started
7952 this instantiation. */
7956 }
7958 /* We're instantiating a deferred template; restore the template
7959 instantiation context in which the instantiation was requested, which
7960 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
7962 static tree
7964 {
7976 }
7978 /* Returns the TINST_LEVEL which gives the original instantiation
7979 context. */
7983 {
7989 }
7991 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
7992 vector of template arguments, as for tsubst.
7994 Returns an appropriate tsubst'd friend declaration. */
7996 static tree
7998 {
7999 tree new_friend;
8004 /* This was a friend declared with an explicit template
8005 argument list, e.g.:
8007 friend void f<>(T);
8009 to indicate that f was a template instantiation, not a new
8010 function declaration. Now, we have to figure out what
8011 instantiation of what template. */
8012 {
8014 tree new_args;
8015 tree tmpl;
8018 /* Friend functions are looked up in the containing namespace scope.
8019 We must enter that scope, to avoid finding member functions of the
8020 current class with same name. */
8035 tsk_none);
8037 }
8041 /* The NEW_FRIEND will look like an instantiation, to the
8042 compiler, but is not an instantiation from the point of view of
8043 the language. For example, we might have had:
8045 template <class T> struct S {
8046 template <class U> friend void f(T, U);
8047 };
8049 Then, in S<int>, template <class U> void f(int, U) is not an
8050 instantiation of anything. */
8056 {
8060 }
8062 /* The mangled name for the NEW_FRIEND is incorrect. The function
8063 is not a template instantiation and should not be mangled like
8064 one. Therefore, we forget the mangling here; we'll recompute it
8065 later if we need it. */
8067 {
8070 }
8073 {
8074 tree old_decl;
8075 tree new_friend_template_info;
8076 tree new_friend_result_template_info;
8077 tree ns;
8080 /* We must save some information from NEW_FRIEND before calling
8081 duplicate decls since that function will free NEW_FRIEND if
8082 possible. */
8084 new_friend_is_defn =
8089 {
8090 /* This declaration is a `primary' template. */
8093 new_friend_result_template_info
8095 }
8096 else
8099 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8103 /* Inside pushdecl_namespace_level, we will push into the
8104 current namespace. However, the friend function should go
8105 into the namespace of the template. */
8115 {
8116 /* This new friend declaration matched an existing
8117 declaration. For example, given:
8119 template <class T> void f(T);
8120 template <class U> class C {
8121 template <class T> friend void f(T) {}
8122 };
8124 the friend declaration actually provides the definition
8125 of `f', once C has been instantiated for some type. So,
8126 old_decl will be the out-of-class template declaration,
8127 while new_friend is the in-class definition.
8129 But, if `f' was called before this point, the
8130 instantiation of `f' will have DECL_TI_ARGS corresponding
8131 to `T' but not to `U', references to which might appear
8132 in the definition of `f'. Previously, the most general
8133 template for an instantiation of `f' was the out-of-class
8134 version; now it is the in-class version. Therefore, we
8135 run through all specialization of `f', adding to their
8136 DECL_TI_ARGS appropriately. In particular, they need a
8137 new set of outer arguments, corresponding to the
8138 arguments for this class instantiation.
8140 The same situation can arise with something like this:
8142 friend void f(int);
8143 template <class T> class C {
8144 friend void f(T) {}
8145 };
8147 when `C<int>' is instantiated. Now, `f(int)' is defined
8148 in the class. */
8151 /* On the other hand, if the in-class declaration does
8152 *not* provide a definition, then we don't want to alter
8153 existing definitions. We can just leave everything
8154 alone. */
8155 ;
8156 else
8157 {
8161 /* Overwrite whatever template info was there before, if
8162 any, with the new template information pertaining to
8163 the declaration. */
8167 {
8168 /* We should have called reregister_specialization in
8169 duplicate_decls. */
8174 /* Instantiate it if the global has already been used. */
8178 }
8179 else
8180 {
8181 tree t;
8183 /* Indicate that the old function template is a partial
8184 instantiation. */
8192 /* Reassign any specializations already in the hash table
8193 to the new more general template, and add the
8194 additional template args. */
8198 {
8200 spec_entry elt;
8212 register_specialization
8215 }
8217 }
8218 }
8220 /* The information from NEW_FRIEND has been merged into OLD_DECL
8221 by duplicate_decls. */
8223 }
8224 }
8225 else
8226 {
8230 /* In the code
8231 template <class T> class C {
8232 template <class U> friend void C1<U>::f (); // case 1
8233 friend void C2<T>::f (); // case 2
8234 };
8235 we only need to make sure CONTEXT is a complete type for
8236 case 2. To distinguish between the two cases, we note that
8237 CONTEXT of case 1 remains dependent type after tsubst while
8238 this isn't true for case 2. */
8248 {
8249 /* Check to see that the declaration is really present, and,
8250 possibly obtain an improved declaration. */
8256 }
8257 }
8260 }
8262 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8263 template arguments, as for tsubst.
8265 Returns an appropriate tsubst'd friend type or error_mark_node on
8266 failure. */
8268 static tree
8270 {
8271 tree friend_type;
8272 tree tmpl;
8273 tree context;
8276 {
8279 }
8284 {
8287 else
8289 }
8291 /* Look for a class template declaration. We look for hidden names
8292 because two friend declarations of the same template are the
8293 same. For example, in:
8295 struct A {
8296 template <typename> friend class F;
8297 };
8298 template <typename> struct B {
8299 template <typename> friend class F;
8300 };
8302 both F templates are the same. */
8306 /* But, if we don't find one, it might be because we're in a
8307 situation like this:
8309 template <class T>
8310 struct S {
8311 template <class U>
8312 friend struct S;
8313 };
8315 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8316 for `S<int>', not the TEMPLATE_DECL. */
8318 {
8321 }
8324 {
8325 /* The friend template has already been declared. Just
8326 check to see that the declarations match, and install any new
8327 default parameters. We must tsubst the default parameters,
8328 of course. We only need the innermost template parameters
8329 because that is all that redeclare_class_template will look
8330 at. */
8333 {
8334 tree parms;
8335 location_t saved_input_location;
8344 }
8347 }
8348 else
8349 {
8350 /* The friend template has not already been declared. In this
8351 case, the instantiation of the template class will cause the
8352 injection of this template into the global scope. */
8357 /* The new TMPL is not an instantiation of anything, so we
8358 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
8359 the new type because that is supposed to be the corresponding
8360 template decl, i.e., TMPL. */
8367 /* Inject this template into the global scope. */
8369 }
8372 {
8375 else
8377 }
8380 }
8382 /* Returns zero if TYPE cannot be completed later due to circularity.
8383 Otherwise returns one. */
8385 static int
8387 {
8397 else
8399 }
8401 /* Apply any attributes which had to be deferred until instantiation
8402 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
8403 ARGS, COMPLAIN, IN_DECL are as tsubst. */
8405 static void
8408 {
8410 tree t;
8415 {
8419 }
8422 {
8426 }
8427 else
8431 {
8436 {
8439 {
8442 /* If the first attribute argument is an identifier, don't
8443 pass it through tsubst. Attributes like mode, format,
8444 cleanup and several target specific attributes expect it
8445 unmodified. */
8451 {
8452 tree chain
8454 in_decl,
8459 chain);
8460 }
8461 else
8467 }
8468 else
8470 }
8473 }
8474 }
8476 /* Perform (or defer) access check for typedefs that were referenced
8477 from within the template TMPL code.
8478 This is a subroutine of instantiate_decl and instantiate_class_template.
8479 TMPL is the template to consider and TARGS is the list of arguments of
8480 that template. */
8482 static void
8484 {
8485 location_t saved_location;
8496 {
8508 /* Make access check error messages point to the location
8509 of the use of the typedef. */
8513 tf_warning_or_error);
8514 }
8516 }
8518 static tree
8520 {
8522 tree typedecl;
8523 tree pbinfo;
8524 tree base_list;
8526 tree fn_context;
8535 /* Figure out which template is being instantiated. */
8539 /* Determine what specialization of the original template to
8540 instantiate. */
8543 {
8546 }
8548 {
8549 /* This TYPE is actually an instantiation of a partial
8550 specialization. We replace the innermost set of ARGS with
8551 the arguments appropriate for substitution. For example,
8552 given:
8554 template <class T> struct S {};
8555 template <class T> struct S<T*> {};
8557 and supposing that we are instantiating S<int*>, ARGS will
8558 presently be {int*} -- but we need {int}. */
8561 }
8562 else
8563 {
8566 }
8568 /* If the template we're instantiating is incomplete, then clearly
8569 there's nothing we can do. */
8573 /* If we've recursively instantiated too many templates, stop. */
8577 /* Now we're really doing the instantiation. Mark the type as in
8578 the process of being defined. */
8581 /* We may be in the middle of deferred access check. Disable
8582 it now. */
8588 /* Use #pragma pack from the template context. */
8594 /* Set the input location to the most specialized template definition.
8595 This is needed if tsubsting causes an error. */
8607 {
8610 /* Adjust visibility for template arguments. */
8612 }
8617 /* We should never instantiate a nested class before its enclosing
8618 class; we need to look up the nested class by name before we can
8619 instantiate it, and that lookup should instantiate the enclosing
8620 class. */
8626 {
8627 tree pbase_binfo;
8628 tree pushed_scope;
8631 /* We must enter the scope containing the type, as that is where
8632 the accessibility of types named in dependent bases are
8633 looked up from. */
8636 /* Substitute into each of the bases to determine the actual
8637 basetypes. */
8639 {
8640 tree base;
8646 {
8647 expanded_bases =
8654 }
8657 {
8659 /* Extract the already-expanded base class. */
8661 else
8662 /* Substitute to figure out the base class. */
8664 NULL_TREE);
8672 }
8673 }
8675 /* The list is now in reverse order; correct that. */
8680 }
8681 /* Now call xref_basetypes to set up all the base-class
8682 information. */
8690 /* Now that our base classes are set up, enter the scope of the
8691 class, so that name lookups into base classes, etc. will work
8692 correctly. This is precisely analogous to what we do in
8693 begin_class_definition when defining an ordinary non-template
8694 class, except we also need to push the enclosing classes. */
8697 /* Now members are processed in the order of declaration. */
8700 {
8704 {
8706 {
8707 /* Build new CLASSTYPE_NESTED_UTDS. */
8709 tree newtag;
8715 /* If the member is a class template, then -- even after
8716 substitution -- there may be dependent types in the
8717 template argument list for the class. We increment
8718 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
8719 that function will assume that no types are dependent
8720 when outside of a template. */
8730 {
8734 /* Unfortunately, lookup_template_class sets
8735 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
8736 instantiation (i.e., for the type of a member
8737 template class nested within a template class.)
8738 This behavior is required for
8739 maybe_process_partial_specialization to work
8740 correctly, but is not accurate in this case;
8741 the TAG is not an instantiation of anything.
8742 (The corresponding TEMPLATE_DECL is an
8743 instantiation, but the TYPE is not.) */
8746 /* Now, we call pushtag to put this NEWTAG into the scope of
8747 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
8748 pushtag calling push_template_decl. We don't have to do
8749 this for enums because it will already have been done in
8750 tsubst_enum. */
8754 }
8755 }
8758 {
8759 /* Build new TYPE_METHODS. */
8760 tree r;
8769 /* Instantiate members marked with attribute used. */
8772 }
8773 else
8774 {
8775 /* Build new TYPE_FIELDS. */
8777 {
8778 tree condition;
8781 condition =
8791 }
8793 {
8794 tree r;
8796 /* The file and line for this declaration, to
8797 assist in error message reporting. Since we
8798 called push_tinst_level above, we don't need to
8799 restore these. */
8808 {
8809 /* In [temp.inst]:
8811 [t]he initialization (and any associated
8812 side-effects) of a static data member does
8813 not occur unless the static data member is
8814 itself used in a way that requires the
8815 definition of the static data member to
8816 exist.
8818 Therefore, we do not substitute into the
8819 initialized for the static data member here. */
8820 finish_static_data_member_decl
8826 /* Instantiate members marked with attribute used. */
8829 }
8831 {
8832 /* Determine whether R has a valid type and can be
8833 completed later. If R is invalid, then it is
8834 replaced by error_mark_node so that it will not be
8835 added to TYPE_FIELDS. */
8841 {
8844 }
8845 }
8847 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
8848 such a thing will already have been added to the field
8849 list by tsubst_enum in finish_member_declaration in the
8850 CLASSTYPE_NESTED_UTDS case above. */
8854 {
8857 }
8858 }
8859 }
8860 }
8861 else
8862 {
8865 {
8866 /* Build new CLASSTYPE_FRIEND_CLASSES. */
8872 {
8873 /* template <class T> friend class C; */
8876 }
8878 {
8879 /* template <class T> friend class C::D; */
8885 }
8888 {
8889 /* This could be either
8891 friend class T::C;
8893 when dependent_type_p is false or
8895 template <class U> friend class T::C;
8897 otherwise. */
8900 /* Bump processing_template_decl for correct
8901 dependent_type_p calculation. */
8906 }
8909 {
8910 /* friend class C;
8912 where C hasn't been declared yet. Let's lookup name
8913 from namespace scope directly, bypassing any name that
8914 come from dependent base class. */
8917 /* The call to xref_tag_from_type does injection for friend
8918 classes. */
8920 friend_type =
8924 }
8926 /* friend class C<T>; */
8929 /* Otherwise it's
8931 friend class C;
8933 where C is already declared or
8935 friend class C<int>;
8937 We don't have to do anything in these cases. */
8940 /* Trick make_friend_class into realizing that the friend
8941 we're adding is a template, not an ordinary class. It's
8942 important that we use make_friend_class since it will
8943 perform some error-checking and output cross-reference
8944 information. */
8952 }
8953 else
8954 {
8955 /* Build new DECL_FRIENDLIST. */
8956 tree r;
8958 /* The file and line for this declaration, to
8959 assist in error message reporting. Since we
8960 called push_tinst_level above, we don't need to
8961 restore these. */
8965 {
8968 }
8973 {
8976 }
8977 }
8978 }
8979 }
8982 {
8985 {
8988 }
8989 else
8991 }
8993 /* Set the file and line number information to whatever is given for
8994 the class itself. This puts error messages involving generated
8995 implicit functions at a predictable point, and the same point
8996 that would be used for non-template classes. */
9003 /* We don't instantiate default arguments for member functions. 14.7.1:
9005 The implicit instantiation of a class template specialization causes
9006 the implicit instantiation of the declarations, but not of the
9007 definitions or default arguments, of the class member functions,
9008 member classes, static data members and member templates.... */
9010 /* Some typedefs referenced from within the template code need to be access
9011 checked at template instantiation time, i.e now. These types were
9012 added to the template at parsing time. Let's get those and perform
9013 the access checks then. */
9023 /* The vtable for a template class can be emitted in any translation
9024 unit in which the class is instantiated. When there is no key
9025 method, however, finish_struct_1 will already have added TYPE to
9026 the keyed_classes list. */
9031 }
9033 /* Wrapper for instantiate_class_template_1. */
9035 tree
9037 {
9038 tree ret;
9043 }
9045 static tree
9047 {
9048 tree r;
9054 else
9055 {
9062 /* Preserve the raw-reference nature of T. */
9066 }
9068 }
9070 /* Given a function parameter pack TMPL_PARM and some function parameters
9071 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
9072 and set *SPEC_P to point at the next point in the list. */
9074 static tree
9076 {
9077 /* Collect all of the extra "packed" parameters into an
9078 argument pack. */
9079 tree parmvec;
9080 tree parmtypevec;
9091 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
9096 {
9099 }
9101 /* Build the argument packs. */
9108 }
9110 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9111 NONTYPE_ARGUMENT_PACK. */
9113 static tree
9115 {
9117 }
9119 /* Return true iff the Ith element of the argument pack ARG_PACK is a
9120 pack expansion. */
9122 static bool
9124 {
9129 }
9132 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
9134 static tree
9136 {
9143 }
9145 /* This is a subroutine of tsubst_pack_expansion.
9147 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
9148 mechanism to store the (non complete list of) arguments of the
9149 substitution and return a non substituted pack expansion, in order
9150 to wait for when we have enough arguments to really perform the
9151 substitution. */
9153 static bool
9157 {
9163 {
9166 parm_pack;
9168 {
9173 else
9175 }
9177 /* If one pack has an expansion and another pack has a normal
9178 argument or if one pack has an empty argument another one
9179 hasn't then tsubst_pack_expansion cannot perform the
9180 substitution and need to fall back on the
9181 PACK_EXPANSION_EXTRA mechanism. */
9185 }
9187 }
9189 /* [temp.variadic]/6 says that:
9191 The instantiation of a pack expansion [...]
9192 produces a list E1,E2, ..., En, where N is the number of elements
9193 in the pack expansion parameters.
9195 This subroutine of tsubst_pack_expansion produces one of these Ei.
9197 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
9198 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
9199 PATTERN, and each TREE_VALUE is its corresponding argument pack.
9200 INDEX is the index 'i' of the element Ei to produce. ARGS,
9201 COMPLAIN, and IN_DECL are the same parameters as for the
9202 tsubst_pack_expansion function.
9204 The function returns the resulting Ei upon successful completion,
9205 or error_mark_node.
9207 Note that this function possibly modifies the ARGS parameter, so
9208 it's the responsibility of the caller to restore it. */
9210 static tree
9212 tree parm_packs,
9214 tree args /* This parm gets
9216 tsubst_flags_t complain,
9217 tree in_decl)
9218 {
9219 tree t;
9222 /* For each parameter pack, change the substitution of the parameter
9223 pack to the ith argument in its argument pack, then expand the
9224 pattern. */
9226 {
9231 ith_elem_is_expansion |=
9234 /* Select the Ith argument from the pack. */
9236 {
9238 {
9242 }
9243 else
9245 }
9246 else
9247 {
9252 {
9254 /* Update the corresponding argument. */
9256 }
9257 else
9258 /* Re-use the ARGUMENT_PACK_SELECT. */
9260 }
9262 }
9264 /* Substitute into the PATTERN with the (possibly altered)
9265 arguments. */
9269 else
9272 /* If the Ith argument pack element is a pack expansion, then
9273 the Ith element resulting from the substituting is going to
9274 be a pack expansion as well. */
9279 }
9281 /* Substitute ARGS into T, which is an pack expansion
9282 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
9283 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
9284 (if only a partial substitution could be performed) or
9285 ERROR_MARK_NODE if there was an error. */
9286 tree
9288 tree in_decl)
9289 {
9290 tree pattern;
9294 tree result;
9302 /* Add in any args remembered from an earlier partial instantiation. */
9307 /* Determine the argument packs that will instantiate the parameter
9308 packs used in the expansion expression. While we're at it,
9309 compute the number of arguments to be expanded and make sure it
9310 is consistent. */
9313 {
9320 {
9324 else
9327 }
9329 {
9332 else
9333 {
9334 /* We can't rely on local_specializations for a parameter
9335 name used later in a function declaration (such as in a
9336 late-specified return type). Even if it exists, it might
9337 have the wrong value for a recursive call. Just make a
9338 dummy decl, since it's only used for its type. */
9341 /* Partial instantiation of the parm_pack, we can't build
9342 up an argument pack yet. */
9344 else
9347 }
9348 }
9349 else
9350 {
9356 }
9363 /* This can only happen if we forget to expand an argument
9364 pack somewhere else. Just return an error, silently. */
9365 {
9369 }
9372 {
9376 /* Don't bother trying to do a partial substitution with
9377 incomplete packs; we'll try again after deduction. */
9384 {
9390 pattern);
9391 else
9394 pattern);
9396 }
9398 /* Keep track of the parameter packs and their corresponding
9399 argument packs. */
9402 }
9403 else
9404 {
9405 /* We can't substitute for this parameter pack. We use a flag as
9406 well as the missing_level counter because function parameter
9407 packs don't have a level. */
9409 }
9410 }
9412 /* We cannot expand this expansion expression, because we don't have
9413 all of the argument packs we need. */
9415 {
9416 /* We got some full packs, but we can't substitute them in until we
9417 have values for all the packs. So remember these until then. */
9422 }
9424 {
9425 /* There were no real arguments, we're just replacing a parameter
9426 pack with another version of itself. Substitute into the
9427 pattern and return a PACK_EXPANSION_*. The caller will need to
9428 deal with that. */
9432 else
9436 }
9441 {
9442 /* We're in a late-specified return type, so create our own local
9443 specializations map; the current map is either NULL or (in the
9444 case of recursive unification) might have bindings that we don't
9445 want to use or alter. */
9448 }
9450 /* For each argument in each argument pack, substitute into the
9451 pattern. */
9454 {
9456 i,
9458 in_decl);
9461 {
9464 }
9465 }
9467 /* Update ARGS to restore the substitution from parameter packs to
9468 their argument packs. */
9470 {
9475 else
9476 {
9484 /* Update the corresponding argument. */
9488 else
9490 }
9491 }
9494 {
9497 }
9500 }
9502 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
9503 TMPL. We do this using DECL_PARM_INDEX, which should work even with
9504 parameter packs; all parms generated from a function parameter pack will
9505 have the same DECL_PARM_INDEX. */
9507 tree
9509 {
9511 tree patparm;
9514 {
9520 }
9521 else
9522 {
9527 }
9530 }
9532 /* Substitute ARGS into the vector or list of template arguments T. */
9534 static tree
9536 {
9548 {
9550 tree new_arg;
9555 {
9556 /* Substitute into an expansion expression. */
9560 /* Add to the expanded length adjustment the number of
9561 expanded arguments. We subtract one from this
9562 measurement, because the argument pack expression
9563 itself is already counted as 1 in
9564 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
9565 the argument pack is empty. */
9567 }
9569 {
9570 /* Substitute into each of the arguments. */
9576 new_arg,
9590 }
9591 }
9592 else
9601 }
9606 /* Make space for the expanded arguments coming from template
9607 argument packs. */
9609 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
9610 arguments for a member template.
9611 In that case each TREE_VEC in ORIG_T represents a level of template
9612 arguments, and ORIG_T won't carry any non defaulted argument count.
9613 It will rather be the nested TREE_VECs that will carry one.
9614 In other words, ORIG_T carries a non defaulted argument count only
9615 if it doesn't contain any nested TREE_VEC. */
9617 {
9621 }
9623 {
9627 {
9630 /* Now expand the template argument pack "in place". */
9633 }
9634 else
9635 {
9637 out++;
9638 }
9639 }
9642 }
9644 /* Return the result of substituting ARGS into the template parameters
9645 given by PARMS. If there are m levels of ARGS and m + n levels of
9646 PARMS, then the result will contain n levels of PARMS. For
9647 example, if PARMS is `template <class T> template <class U>
9648 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
9649 result will be `template <int*, double, class V>'. */
9651 static tree
9653 {
9657 /* When substituting into a template, we must set
9658 PROCESSING_TEMPLATE_DECL as the template parameters may be
9659 dependent if they are based on one-another, and the dependency
9660 predicates are short-circuit outside of templates. */
9667 {
9668 tree new_vec =
9673 {
9674 tree tuple;
9686 }
9692 }
9697 }
9699 /* Return the result of substituting ARGS into one template parameter
9700 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
9701 parameter and which TREE_PURPOSE is the default argument of the
9702 template parameter. */
9704 static tree
9706 {
9727 }
9729 /* Substitute the ARGS into the indicated aggregate (or enumeration)
9730 type T. If T is not an aggregate or enumeration type, it is
9731 handled as if by tsubst. IN_DECL is as for tsubst. If
9732 ENTERING_SCOPE is nonzero, T is the context for a template which
9733 we are presently tsubst'ing. Return the substituted value. */
9735 static tree
9737 tree args,
9738 tsubst_flags_t complain,
9739 tree in_decl,
9741 {
9746 {
9751 /* Else fall through. */
9755 {
9756 tree argvec;
9757 tree context;
9758 tree r;
9762 /* In "sizeof(X<I>)" we need to evaluate "I". */
9768 /* First, determine the context for the type we are looking
9769 up. */
9772 {
9775 /* If context is a nested class inside a class template,
9776 it may still need to be instantiated (c++/33959). */
9778 }
9780 /* Then, figure out what arguments are appropriate for the
9781 type we are trying to find. For example, given:
9783 template <class T> struct S;
9784 template <class T, class U> void f(T, U) { S<U> su; }
9786 and supposing that we are instantiating f<int, double>,
9787 then our ARGS will be {int, double}, but, when looking up
9788 S we only want {double}. */
9793 else
9794 {
9798 }
9804 }
9805 else
9806 /* This is not a template type, so there's nothing to do. */
9811 }
9812 }
9814 /* Substitute into the default argument ARG (a default argument for
9815 FN), which has the indicated TYPE. */
9817 tree
9819 {
9824 /* This can happen in invalid code. */
9828 /* This default argument came from a template. Instantiate the
9829 default argument here, not in tsubst. In the case of
9830 something like:
9832 template <class T>
9833 struct S {
9834 static T t();
9835 void f(T = t());
9836 };
9838 we must be careful to do name lookup in the scope of S<T>,
9839 rather than in the current class. */
9841 /* The "this" pointer is not valid in a default argument. */
9843 {
9848 }
9851 /* The default argument expression may cause implicitly defined
9852 member functions to be synthesized, which will result in garbage
9853 collection. We must treat this situation as if we were within
9854 the body of function so as to avoid collecting live data on the
9855 stack. */
9863 /* Restore the "this" pointer. */
9865 {
9868 }
9874 /* Make sure the default argument is reasonable. */
9880 }
9882 /* Substitute into all the default arguments for FN. */
9884 static void
9886 {
9887 tree arg;
9888 tree tmpl_args;
9892 /* If this function is not yet instantiated, we certainly don't need
9893 its default arguments. */
9896 /* Don't do this again for clones. */
9901 arg;
9907 }
9909 /* Substitute the ARGS into the T, which is a _DECL. Return the
9910 result of the substitution. Issue error and warning messages under
9911 control of COMPLAIN. */
9913 static tree
9915 {
9916 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
9917 location_t saved_loc;
9922 /* Set the filename and linenumber to improve error-reporting. */
9927 {
9929 {
9930 /* We can get here when processing a member function template,
9931 member class template, or template template parameter. */
9933 tree spec;
9934 tree tmpl_args;
9935 tree full_args;
9938 {
9939 /* Template template parameter is treated here. */
9943 /* If we get a real template back, return it. This can happen in
9944 the context of most_specialized_class. */
9956 complain);
9959 }
9961 /* We might already have an instance of this template.
9962 The ARGS are for the surrounding class type, so the
9963 full args contain the tsubst'd args for the context,
9964 plus the innermost args from the template decl. */
9968 /* Because this is a template, the arguments will still be
9969 dependent, even after substitution. If
9970 PROCESSING_TEMPLATE_DECL is not set, the dependency
9971 predicates will short-circuit. */
9979 /* If this is a default template template argument,
9980 tsubst might not have changed anything. */
9987 {
9990 }
9992 /* Make a new template decl. It will be similar to the
9993 original, but will record the current template arguments.
9994 We also create a new function declaration, which is just
9995 like the old one, but points to this new template, rather
9996 than the old one. */
10005 {
10006 tree new_type;
10018 }
10019 else
10020 {
10021 tree new_decl;
10033 }
10039 /* The template parameters for this new template are all the
10040 template parameters for the old template, except the
10041 outermost level of parameters. */
10044 complain);
10050 /* Record this non-type partial instantiation. */
10054 }
10058 {
10059 tree ctx;
10062 tree gen_tmpl;
10063 tree type;
10068 /* Nobody should be tsubst'ing into non-template functions. */
10072 {
10073 tree spec;
10076 /* If T is not dependent, just return it. We have to
10077 increment PROCESSING_TEMPLATE_DECL because
10078 value_dependent_expression_p assumes that nothing is
10079 dependent when PROCESSING_TEMPLATE_DECL is zero. */
10086 /* Calculate the most general template of which R is a
10087 specialization, and the complete set of arguments used to
10088 specialize R. */
10091 (DECL_TEMPLATE_RESULT
10097 /* Check to see if we already have this specialization. */
10102 {
10105 }
10107 /* We can see more levels of arguments than parameters if
10108 there was a specialization of a member template, like
10109 this:
10111 template <class T> struct S { template <class U> void f(); }
10112 template <> template <class U> void S<int>::f(U);
10114 Here, we'll be substituting into the specialization,
10115 because that's where we can find the code we actually
10116 want to generate, but we'll have enough arguments for
10117 the most general template.
10119 We also deal with the peculiar case:
10121 template <class T> struct S {
10122 template <class U> friend void f();
10123 };
10124 template <class U> void f() {}
10125 template S<int>;
10126 template void f<double>();
10128 Here, the ARGS for the instantiation of will be {int,
10129 double}. But, we only need as many ARGS as there are
10130 levels of template parameters in CODE_PATTERN. We are
10131 careful not to get fooled into reducing the ARGS in
10132 situations like:
10134 template <class T> struct S { template <class U> void f(U); }
10135 template <class T> template <> void S<T>::f(int) {}
10137 which we can spot because the pattern will be a
10138 specialization in this case. */
10140 parms_depth =
10145 }
10146 else
10147 {
10148 /* This special case arises when we have something like this:
10150 template <class T> struct S {
10151 friend void f<int>(int, double);
10152 };
10154 Here, the DECL_TI_TEMPLATE for the friend declaration
10155 will be an IDENTIFIER_NODE. We are being called from
10156 tsubst_friend_function, and we want only to create a
10157 new decl (R) with appropriate types so that we can call
10158 determine_specialization. */
10160 }
10163 {
10166 else
10170 }
10171 else
10172 {
10175 }
10180 /* If we hit excessive deduction depth, the type is bogus even if
10181 it isn't error_mark_node, so don't build a decl. */
10185 /* We do NOT check for matching decls pushed separately at this
10186 point, as they may not represent instantiations of this
10187 template, and in any case are considered separate under the
10188 discrete model. */
10192 /* Clear out the mangled name and RTL for the instantiation. */
10195 /* Leave DECL_INITIAL set on deleted instantiations. */
10201 /* Type-conversion operator. Reconstruct the name, in
10202 case it's the name of one of the template's parameters. */
10212 /* If this is an instantiation of a function with internal
10213 linkage, we already know what object file linkage will be
10214 assigned to the instantiation. */
10223 /* We'll re-clone as appropriate in instantiate_template. */
10226 /* If we aren't complaining now, return on error before we register
10227 the specialization so that we'll complain eventually. */
10233 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
10234 this in the special friend case mentioned above where
10235 GEN_TMPL is NULL. */
10237 {
10243 /* We're not supposed to instantiate default arguments
10244 until they are called, for a template. But, for a
10245 declaration like:
10247 template <class T> void f ()
10248 { extern void g(int i = T()); }
10250 we should do the substitution when the template is
10251 instantiated. We handle the member function case in
10252 instantiate_class_template since the default arguments
10253 might refer to other members of the class. */
10258 }
10259 else
10262 /* Copy the list of befriending classes. */
10266 {
10270 in_decl);
10271 }
10274 {
10280 /* If this is an instantiation of a member template, clone it.
10281 If it isn't, that'll be handled by
10282 clone_constructors_and_destructors. */
10285 }
10296 /* Possibly limit visibility based on template args. */
10299 {
10303 }
10311 }
10315 {
10323 {
10324 /* If there is a local specialization that isn't a
10325 parameter pack, it means that we're doing a "simple"
10326 substitution from inside tsubst_pack_expansion. Just
10327 return the local specialization (which will be a single
10328 parm). */
10335 /* Expand the TYPE_PACK_EXPANSION that provides the types for
10336 the parameters in this function parameter pack. */
10340 {
10343 /* Zero-length parameter packs are boring. Just substitute
10344 into the chain. */
10348 }
10349 else
10350 {
10351 /* All we did was update the type. Make a note of that. */
10354 }
10355 }
10357 /* Loop through all of the parameter's we'll build. When T is
10358 a function parameter pack, LEN is the number of expanded
10359 types in EXPANDED_TYPES; otherwise, LEN is 1. */
10362 {
10369 /* We're on the Ith parameter of the function parameter
10370 pack. */
10371 {
10372 /* An argument of a function parameter pack is not a parameter
10373 pack. */
10376 /* Get the Ith type. */
10379 /* Rename the parameter to include the index. */
10382 }
10384 /* We're dealing with a normal parameter. */
10392 {
10395 else
10398 }
10408 /* Keep track of the first new parameter we
10409 generate. That's what will be returned to the
10410 caller. */
10414 /* Build a proper chain of parameters when substituting
10415 into a function parameter pack. */
10418 }
10420 /* If cp_unevaluated_operand is set, we're just looking for a
10421 single dummy parameter, so don't keep going. */
10426 /* FIRST_R contains the start of the chain we've built. */
10428 }
10432 {
10433 tree type;
10443 /* For bit-fields, DECL_INITIAL gives the number of bits. For
10444 non-bit-fields DECL_INITIAL is a non-static data member
10445 initializer, which gets deferred instantiation. */
10451 {
10452 /* Set up DECL_TEMPLATE_INFO so that we can get at the
10453 NSDMI in perform_member_init. Still set DECL_INITIAL
10454 so that we know there is one. */
10459 }
10460 /* We don't have to set DECL_CONTEXT here; it is set by
10461 finish_member_declaration. */
10468 }
10472 /* We reach here only for member using decls. We also need to check
10473 uses_template_parms because DECL_DEPENDENT_P is not set for a
10474 using-declaration that designates a member of the current
10475 instantiation (c++/53549). */
10478 {
10489 else
10490 {
10493 }
10494 }
10495 else
10496 {
10499 }
10504 {
10507 tree spec;
10509 tree ctx;
10515 {
10516 /* If this is the canonical decl, we don't have to
10517 mess with instantiations, and often we can't (for
10518 typename, template type parms and such). Note that
10519 TYPE_NAME is not correct for the above test if
10520 we've copied the type for a typedef. */
10526 }
10528 /* Check to see if we already have the specialization we
10529 need. */
10532 {
10533 /* T is a static data member or namespace-scope entity.
10534 We have to substitute into namespace-scope variables
10535 (even though such entities are never templates) because
10536 of cases like:
10538 template <class T> void f() { extern T t; }
10540 where the entity referenced is not known until
10541 instantiation time. */
10545 {
10547 complain,
10549 /* If CTX is unchanged, then T is in fact the
10550 specialization we want. That situation occurs when
10551 referencing a static data member within in its own
10552 class. We can use pointer equality, rather than
10553 same_type_p, because DECL_CONTEXT is always
10554 canonical... */
10557 /* ... unless T is a member template; in which
10558 case our caller can be willing to create a
10559 specialization of that template represented
10560 by T. */
10564 }
10567 {
10575 }
10576 }
10577 else
10578 {
10579 /* A local variable. */
10581 /* Subsequent calls to pushdecl will fill this in. */
10584 }
10585 /* If we already have the specialization we need, there is
10586 nothing more to do. */
10588 {
10591 }
10594 {
10595 /* Just use name lookup to find a member alias for an anonymous
10596 union, but then add it to the hash table. */
10601 }
10603 /* Create a new node for the specialization we need. */
10606 {
10609 else
10616 }
10618 {
10619 /* Even if the original location is out of scope, the
10620 newly substituted one is not. */
10627 {
10628 /* It may seem that this case cannot occur, since:
10630 typedef void f();
10631 void g() { f x; }
10633 declares a function, not a variable. However:
10635 typedef void f();
10636 template <typename T> void g() { T t; }
10637 template void g<f>();
10639 is an attempt to declare a variable with function
10640 type. */
10642 /* R is not yet sufficiently initialized, so we
10643 just use its name. */
10646 }
10648 /* Wait until cp_finish_decl to set this again, to handle
10649 circular dependency (template/instantiate6.C). */
10654 {
10659 {
10662 }
10664 }
10665 }
10671 /* Clear out the mangled name and RTL for the instantiation. */
10675 /* The initializer must not be expanded until it is required;
10676 see [temp.inst]. */
10682 {
10683 /* Possibly limit visibility based on template args. */
10686 {
10690 }
10692 }
10695 {
10696 /* A static data member declaration is always marked
10697 external when it is declared in-class, even if an
10698 initializer is present. We mimic the non-template
10699 processing here. */
10705 }
10707 {
10708 /* We're substituting this var in a decltype outside of its
10709 scope, such as for a lambda return type. Don't add it to
10710 local_specializations, do perform auto deduction. */
10713 {
10714 tree init
10720 }
10721 }
10722 else
10731 /* Preserve a typedef that names a type. */
10733 {
10736 }
10739 }
10744 }
10745 #undef RETURN
10747 out:
10748 /* Restore the file and line information. */
10752 }
10754 /* Substitute into the ARG_TYPES of a function type.
10755 If END is a TREE_CHAIN, leave it and any following types
10756 un-substituted. */
10758 static tree
10760 tree args,
10761 tree end,
10762 tsubst_flags_t complain,
10763 tree in_decl)
10764 {
10765 tree remaining_arg_types;
10769 tree default_arg;
10780 {
10781 /* For a pack expansion, perform substitution on the
10782 entire expression. Later on, we'll handle the arguments
10783 one-by-one. */
10788 /* So that we'll spin through the parameters, one by one. */
10790 else
10791 {
10792 /* We only partially substituted into the parameter
10793 pack. Our type is TYPE_PACK_EXPANSION. */
10796 }
10797 }
10810 {
10812 {
10816 }
10818 }
10820 /* Do array-to-pointer, function-to-pointer conversion, and ignore
10821 top-level qualifiers as required. */
10824 /* We do not substitute into default arguments here. The standard
10825 mandates that they be instantiated only when needed, which is
10826 done in build_over_call. */
10830 {
10831 /* We've instantiated a template before its default arguments
10832 have been parsed. This can happen for a nested template
10833 class, and is not an error unless we require the default
10834 argument in a call of this function. */
10835 remaining_arg_types =
10838 }
10839 else
10840 remaining_arg_types =
10842 }
10845 }
10847 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
10848 *not* handle the exception-specification for FNTYPE, because the
10849 initial substitution of explicitly provided template parameters
10850 during argument deduction forbids substitution into the
10851 exception-specification:
10853 [temp.deduct]
10855 All references in the function type of the function template to the
10856 corresponding template parameters are replaced by the specified tem-
10857 plate argument values. If a substitution in a template parameter or
10858 in the function type of the function template results in an invalid
10859 type, type deduction fails. [Note: The equivalent substitution in
10860 exception specifications is done only when the function is instanti-
10861 ated, at which point a program is ill-formed if the substitution
10862 results in an invalid type.] */
10864 static tree
10866 tree args,
10867 tsubst_flags_t complain,
10868 tree in_decl)
10869 {
10870 tree return_type;
10871 tree arg_types;
10872 tree fntype;
10874 /* The TYPE_CONTEXT is not used for function/method types. */
10877 /* Substitute the return type. */
10881 /* The standard does not presently indicate that creation of a
10882 function type with an invalid return type is a deduction failure.
10883 However, that is clearly analogous to creating an array of "void"
10884 or a reference to a reference. This is core issue #486. */
10887 {
10889 {
10892 else
10894 }
10896 }
10898 /* Substitute the argument types. */
10904 /* Construct a new type node and return it. */
10906 {
10909 }
10910 else
10911 {
10914 {
10915 /* [temp.deduct]
10917 Type deduction may fail for any of the following
10918 reasons:
10920 -- Attempting to create "pointer to member of T" when T
10921 is not a class type. */
10924 r);
10926 }
10930 }
10934 }
10936 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
10937 ARGS into that specification, and return the substituted
10938 specification. If there is no specification, return NULL_TREE. */
10940 static tree
10942 tree args,
10943 tsubst_flags_t complain,
10944 tree in_decl,
10946 {
10947 tree specs;
10948 tree new_specs;
10953 {
10954 /* A noexcept-specifier. */
10959 {
10960 /* Defer instantiation of noexcept-specifiers to avoid
10961 excessive instantiations (c++/49107). */
10964 {
10965 /* We already partially instantiated this member template,
10966 so combine the new args with the old. */
10971 }
10972 else
10973 {
10976 }
10977 }
10978 else
10979 new_specs = tsubst_copy_and_build
10983 }
10985 {
10988 else
10990 {
10991 tree spec;
10996 {
10997 /* Expand the pack expansion type. */
11000 in_decl);
11006 else
11007 {
11008 /* We're substituting into a member template, so
11009 we got a TYPE_PACK_EXPANSION back. Add that
11010 expansion and move on. */
11014 expanded_specs,
11015 complain);
11018 }
11019 }
11022 {
11025 else
11030 complain);
11031 }
11034 }
11035 }
11037 }
11039 /* Take the tree structure T and replace template parameters used
11040 therein with the argument vector ARGS. IN_DECL is an associated
11041 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
11042 Issue error and warning messages under control of COMPLAIN. Note
11043 that we must be relatively non-tolerant of extensions here, in
11044 order to preserve conformance; if we allow substitutions that
11045 should not be allowed, we may allow argument deductions that should
11046 not succeed, and therefore report ambiguous overload situations
11047 where there are none. In theory, we could allow the substitution,
11048 but indicate that it should have failed, and allow our caller to
11049 make sure that the right thing happens, but we don't try to do this
11050 yet.
11052 This function is used for dealing with types, decls and the like;
11053 for expressions, use tsubst_expr or tsubst_copy. */
11055 tree
11057 {
11080 else
11085 /* Reuse typedefs. We need to do this to handle dependent attributes,
11086 such as attribute aligned. */
11089 {
11093 {
11094 /* DECL represents an alias template and we want to
11095 instantiate it. */
11099 }
11103 {
11107 }
11112 else
11113 /* The typedef is from a non-template context. */
11117 {
11119 r = cp_build_qualified_type_real
11123 }
11124 else
11125 {
11126 /* We don't have an instantiation yet, so drop the typedef. */
11131 }
11132 }
11145 {
11171 {
11177 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
11178 needed. */
11184 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
11185 with TREE_SIDE_EFFECTS that indicates this is not an integral
11186 constant expression. */
11189 {
11192 }
11195 }
11201 {
11214 {
11218 {
11219 /* See through ARGUMENT_PACK_SELECT arguments. */
11221 /* If the selected argument is an expansion E, that most
11222 likely means we were called from
11223 gen_elem_of_pack_expansion_instantiation during the
11224 substituting of pack an argument pack (which Ith
11225 element is a pack expansion, where I is
11226 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
11227 In this case, the Ith element resulting from this
11228 substituting is going to be a pack expansion, which
11229 pattern is the pattern of E. Let's return the
11230 pattern of E, and
11231 gen_elem_of_pack_expansion_instantiation will
11232 build the resulting pack expansion from it. */
11235 }
11236 }
11241 {
11243 /* If ARG is an argument pack, we don't actually want to
11244 perform a substitution here, because substitutions
11245 for argument packs are only done
11246 element-by-element. We can get to this point when
11247 substituting the type of a non-type template
11248 parameter pack, when that type actually contains
11249 template parameter packs from an outer template, e.g.,
11251 template<typename... Types> struct A {
11252 template<Types... Values> struct B { };
11253 }; */
11257 {
11263 return cp_build_qualified_type_real
11265 }
11267 {
11268 /* We are processing a type constructed from a
11269 template template parameter. */
11280 /* Consider this code:
11282 template <template <class> class Template>
11283 struct Internal {
11284 template <class Arg> using Bind = Template<Arg>;
11285 };
11287 template <template <class> class Template, class Arg>
11288 using Instantiate = Template<Arg>; //#0
11290 template <template <class> class Template,
11291 class Argument>
11292 using Bind =
11293 Instantiate<Internal<Template>::template Bind,
11294 Argument>; //#1
11296 When #1 is parsed, the
11297 BOUND_TEMPLATE_TEMPLATE_PARM representing the
11298 parameter `Template' in #0 matches the
11299 UNBOUND_CLASS_TEMPLATE representing the argument
11300 `Internal<Template>::template Bind'; We then want
11301 to assemble the type `Bind<Argument>' that can't
11302 be fully created right now, because
11303 `Internal<Template>' not being complete, the Bind
11304 template cannot be looked up in that context. So
11305 we need to "store" `Bind<Argument>' for later
11306 when the context of Bind becomes complete. Let's
11307 store that in a TYPENAME_TYPE. */
11311 argvec),
11312 typename_type,
11313 complain);
11315 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
11316 are resolving nested-types in the signature of a
11317 member function templates. Otherwise ARG is a
11318 TEMPLATE_DECL and is the real template to be
11319 instantiated. */
11327 complain);
11328 return cp_build_qualified_type_real
11330 }
11331 else
11332 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
11334 }
11337 /* This can happen during the attempted tsubst'ing in
11338 unify. This means that we don't yet have any information
11339 about the template parameter in question. */
11342 /* Early in template argument deduction substitution, we don't
11343 want to reduce the level of 'auto', or it will be confused
11344 with a normal template parm in subsequent deduction. */
11348 /* If we get here, we must have been looking at a parm for a
11349 more deeply nested template. Make a new version of this
11350 template parameter, but with a lower level. */
11352 {
11357 {
11359 r = cp_build_qualified_type_real
11363 }
11364 else
11365 {
11376 /* We have reduced the level of the template
11377 template parameter, but not the levels of its
11378 template parameters, so canonical_type_parameter
11379 will not be able to find the canonical template
11380 template parameter for this level. Thus, we
11381 require structural equality checking to compare
11382 TEMPLATE_TEMPLATE_PARMs. */
11386 else
11390 {
11398 }
11399 }
11408 }
11411 }
11414 {
11422 {
11426 }
11429 {
11433 }
11436 {
11440 }
11446 }
11449 /* We should never be tsubsting a binfo. */
11453 /* A vector of template arguments. */
11459 {
11463 /* [temp.deduct]
11465 Type deduction may fail for any of the following
11466 reasons:
11468 -- Attempting to create a pointer to reference type.
11469 -- Attempting to create a reference to a reference type or
11470 a reference to void.
11472 Core issue 106 says that creating a reference to a reference
11473 during instantiation is no longer a cause for failure. We
11474 only enforce this check in strict C++98 mode. */
11478 {
11481 /* We keep track of the last time we issued this error
11482 message to avoid spewing a ton of messages during a
11483 single bad template instantiation. */
11486 {
11491 else
11494 }
11497 }
11499 {
11503 }
11505 /* In C++0x, during template argument substitution, when there is an
11506 attempt to create a reference to a reference type, reference
11507 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
11509 "If a template-argument for a template-parameter T names a type
11510 that is a reference to a type A, an attempt to create the type
11511 'lvalue reference to cv T' creates the type 'lvalue reference to
11512 A,' while an attempt to create the type type rvalue reference to
11513 cv T' creates the type T"
11514 */
11515 r = cp_build_reference_type
11518 else
11523 /* Will this ever be needed for TYPE_..._TO values? */
11527 }
11529 {
11532 {
11533 /* [temp.deduct]
11535 Type deduction may fail for any of the following
11536 reasons:
11538 -- Attempting to create "pointer to member of T" when T
11539 is not a class type. */
11543 }
11545 {
11549 }
11551 {
11555 }
11558 {
11559 /* The type of the implicit object parameter gets its
11560 cv-qualifiers from the FUNCTION_TYPE. */
11561 tree memptr;
11565 complain);
11566 }
11567 else
11570 complain);
11571 }
11574 {
11575 tree fntype;
11576 tree specs;
11581 /* Substitute the exception specification. */
11589 }
11591 {
11596 /* As an optimization, we avoid regenerating the array type if
11597 it will obviously be the same as T. */
11601 /* These checks should match the ones in grokdeclarator.
11603 [temp.deduct]
11605 The deduction may fail for any of the following reasons:
11607 -- Attempting to create an array with an element type that
11608 is void, a function type, or a reference type, or [DR337]
11609 an abstract class type. */
11613 {
11617 }
11619 {
11622 type);
11624 }
11629 {
11632 }
11635 }
11638 {
11648 {
11652 }
11654 {
11655 /* Normally, make_typename_type does not require that the CTX
11656 have complete type in order to allow things like:
11658 template <class T> struct S { typename S<T>::X Y; };
11660 But, such constructs have already been resolved by this
11661 point, so here CTX really should have complete type, unless
11662 it's a partial instantiation. */
11665 {
11669 }
11670 }
11677 {
11680 }
11683 {
11685 {
11689 else
11691 }
11693 {
11697 else
11699 }
11700 }
11702 return cp_build_qualified_type_real
11704 }
11707 {
11719 }
11722 {
11723 tree type;
11739 complain);
11740 }
11743 {
11744 tree type;
11760 else
11761 type = finish_decltype_type
11766 complain);
11767 }
11770 {
11774 }
11778 {
11780 tree packed_out =
11782 args,
11783 complain,
11784 in_decl);
11787 /* For template nontype argument packs, also substitute into
11788 the type. */
11793 }
11808 /* We should use one of the expression tsubsts for these codes. */
11814 }
11815 }
11817 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
11818 type of the expression on the left-hand side of the "." or "->"
11819 operator. */
11821 static tree
11824 {
11825 tree name;
11826 tree qualifying_scope;
11827 tree fns;
11828 tree optype;
11833 /* A baselink indicates a function from a base class. Both the
11834 BASELINK_ACCESS_BINFO and the base class referenced may
11835 indicate bases of the template class, rather than the
11836 instantiated class. In addition, lookups that were not
11837 ambiguous before may be ambiguous now. Therefore, we perform
11838 the lookup again. */
11845 {
11852 }
11860 /* If lookup found a single function, mark it as used at this
11861 point. (If it lookup found multiple functions the one selected
11862 later by overload resolution will be marked as used at that
11863 point.) */
11869 /* Add back the template arguments, if present. */
11874 template_args);
11875 /* Update the conversion operator type. */
11883 qualifying_scope,
11884 object_type);
11886 }
11888 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
11889 true if the qualified-id will be a postfix-expression in-and-of
11890 itself; false if more of the postfix-expression follows the
11891 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
11892 of "&". */
11894 static tree
11898 {
11899 tree expr;
11900 tree scope;
11901 tree name;
11903 tree template_args;
11908 /* Figure out what name to look up. */
11911 {
11919 }
11920 else
11921 {
11924 }
11926 /* Substitute into the qualifying scope. When there are no ARGS, we
11927 are just trying to simplify a non-dependent expression. In that
11928 case the qualifying scope may be dependent, and, in any case,
11929 substituting will not help. */
11932 {
11935 }
11936 else
11940 {
11945 }
11948 {
11950 {
11951 /* A BIT_NOT_EXPR is used to represent a destructor. */
11953 {
11957 }
11958 else
11961 }
11962 else
11966 {
11968 {
11972 }
11974 }
11975 }
11978 {
11980 scope);
11981 /* Remember that there was a reference to this entity. */
11983 }
11986 {
11992 }
12001 {
12002 expr = (adjust_result_of_qualified_name_lookup
12004 expr = (finish_qualified_id_expr
12008 }
12010 /* Expressions do not generally have reference type. */
12012 /* However, if we're about to form a pointer-to-member, we just
12013 want the referenced member referenced. */
12018 }
12020 /* Like tsubst, but deals with expressions. This function just replaces
12021 template parms; to finish processing the resultant expression, use
12022 tsubst_copy_and_build or tsubst_expr. */
12024 static tree
12026 {
12028 tree r;
12036 {
12041 {
12042 /* We get here for a use of 'this' in an NSDMI. */
12048 /* This can happen for a parameter name used later in a function
12049 declaration (such as in a late-specified return type). Just
12050 make a dummy decl, since it's only used for its type. */
12053 /* Give it the template pattern as its context; its true context
12054 hasn't been instantiated yet and this is good enough for
12055 mangling. */
12057 }
12065 {
12066 tree enum_type;
12067 tree v;
12071 /* There is no need to substitute into namespace-scope
12072 enumerators. */
12075 /* If ARGS is NULL, then T is known to be non-dependent. */
12079 /* Unfortunately, we cannot just call lookup_name here.
12080 Consider:
12082 template <int I> int f() {
12083 enum E { a = I };
12084 struct S { void g() { E e = a; } };
12085 };
12087 When we instantiate f<7>::S::g(), say, lookup_name is not
12088 clever enough to find f<7>::a. */
12089 enum_type
12099 /* We didn't find the name. That should never happen; if
12100 name-lookup found it during preliminary parsing, we
12101 should find it again here during instantiation. */
12103 }
12108 {
12109 tree ctx;
12114 {
12117 {
12121 }
12123 }
12124 }
12140 /* An OVERLOAD will always be a non-dependent overload set; an
12141 overload set from function scope will just be represented with an
12142 IDENTIFIER_NODE, and from class scope with a BASELINK. */
12157 {
12158 /* Template template argument like the following example need
12159 special treatment:
12161 template <template <class> class TT> struct C {};
12162 template <class T> struct D {
12163 template <class U> struct E {};
12164 C<E> c; // #1
12165 };
12166 D<int> d; // #2
12168 We are processing the template argument `E' in #1 for
12169 the template instantiation #2. Originally, `E' is a
12170 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
12171 have to substitute this with one having context `D<int>'. */
12175 }
12176 else
12177 /* Ordinary template template argument. */
12188 return build1
12194 {
12204 /* We only want to compute the number of arguments. */
12218 {
12225 else
12228 }
12229 else
12231 }
12233 {
12241 }
12242 /* Fall through */
12257 return build1
12262 {
12263 tree object;
12264 tree name;
12269 {
12273 }
12276 {
12286 }
12291 in_decl);
12292 else
12295 }
12333 return build_nt
12346 return build_nt
12353 {
12361 }
12366 {
12367 r = build_nt
12373 }
12376 {
12377 r = build_nt
12383 }
12386 {
12387 r = build_nt
12393 }
12396 {
12397 /* Substituted template arguments */
12406 }
12409 {
12429 }
12454 {
12457 }
12458 else
12462 /* This is handled by tsubst_copy_and_build. */
12468 in_decl),
12472 /* We shouldn't have built any of these during initial template
12473 generation. Instead, they should be built during instantiation
12474 in response to the saved STMT_IS_FULL_EXPR_P setting. */
12478 r = build2
12498 {
12499 /* Instantiate any typedefs in the type. */
12504 }
12507 /* These can sometimes show up in a partial instantiation, but never
12508 involve template parms. */
12513 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
12516 }
12517 }
12519 /* Like tsubst_copy, but specifically for OpenMP clauses. */
12521 static tree
12523 tree in_decl)
12524 {
12528 {
12534 {
12537 {
12543 }
12544 /* FALLTHRU */
12568 }
12569 }
12572 }
12574 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
12576 static tree
12578 tree in_decl)
12579 {
12580 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
12600 {
12603 else
12604 {
12608 }
12609 }
12614 #undef RECUR
12615 }
12617 /* Substitute one OMP_FOR iterator. */
12619 static void
12624 {
12625 #define RECUR(NODE) \
12626 tsubst_expr ((NODE), args, complain, in_decl, \
12627 integral_constant_expression_p)
12635 /* Do this before substituting into decl to handle 'auto'. */
12640 {
12644 }
12649 {
12656 complain);
12657 else
12664 }
12667 {
12668 tree c;
12670 {
12681 }
12683 {
12688 {
12691 }
12692 }
12693 }
12699 else
12703 {
12714 {
12721 }
12722 else
12728 {
12734 }
12738 {
12745 }
12746 else
12752 }
12758 #undef RECUR
12759 }
12761 /* Like tsubst_copy for expressions, etc. but also does semantic
12762 processing. */
12764 static tree
12767 {
12768 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12769 #define RECUR(NODE) \
12770 tsubst_expr ((NODE), args, complain, in_decl, \
12771 integral_constant_expression_p)
12774 tree r;
12775 location_t loc;
12787 {
12789 {
12790 tree_stmt_iterator i;
12794 }
12809 else
12818 {
12820 tree init;
12826 {
12829 tree decl;
12837 else
12839 }
12840 else
12841 {
12845 {
12846 /* By marking the declaration as instantiated, we avoid
12847 trying to instantiate it. Since instantiate_decl can't
12848 handle local variables, and since we've already done
12849 all that needs to be done, that's the right thing to
12850 do. */
12855 /* Anonymous aggregates are a special case. */
12858 {
12861 {
12865 }
12867 }
12870 else
12871 {
12876 {
12877 /* For __PRETTY_FUNCTION__ we have to adjust the
12878 initializer. */
12882 }
12883 else
12884 {
12888 {
12889 /* If we had an initializer but it
12890 instantiated to nothing,
12891 value-initialize the object. This will
12892 only occur when the initializer was a
12893 pack expansion where the parameter packs
12894 used in that expansion were of length
12895 zero. */
12897 complain);
12900 }
12901 else
12903 }
12906 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
12909 }
12910 }
12911 }
12914 }
12929 {
12939 }
12966 {
12970 }
12978 else
12986 else
13013 {
13015 tree label;
13020 }
13026 /* Computed goto's must be tsubst'd into. On the other hand,
13027 non-computed gotos must not be; the identifier in question
13028 will have no binding. */
13030 else
13036 tmp = finish_asm_stmt
13043 {
13048 }
13053 {
13058 }
13059 else
13060 {
13065 else
13072 else
13078 else
13080 }
13084 {
13088 {
13090 /* Prevent instantiate_decl from trying to instantiate
13091 this variable. We've already done all that needs to be
13092 done. */
13095 }
13100 }
13106 {
13107 /* Local classes are not independent templates; they are
13108 instantiated along with their containing function. And this
13109 way we don't have to deal with pushing out of one local class
13110 to instantiate a member of another local class. */
13111 tree fn;
13112 /* Closures are handled by the LAMBDA_EXPR. */
13118 }
13122 {
13123 tree condition;
13126 condition =
13128 args,
13137 }
13158 {
13175 integral_constant_expression_p);
13189 }
13221 {
13226 {
13229 }
13234 }
13235 else
13236 {
13243 {
13246 }
13249 {
13254 {
13257 }
13261 }
13262 else
13263 {
13267 }
13269 }
13273 {
13279 {
13283 {
13288 }
13292 }
13293 else
13294 {
13299 }
13300 }
13318 /* If the first operand was a statement, we're done with it. */
13322 complain));
13329 integral_constant_expression_p));
13330 }
13333 out:
13336 #undef RECUR
13337 #undef RETURN
13338 }
13340 /* T is a postfix-expression that is not being used in a function
13341 call. Return the substituted version of T. */
13343 static tree
13345 tsubst_flags_t complain,
13346 tree in_decl)
13347 {
13351 else
13357 }
13359 /* Like tsubst but deals with expressions and performs semantic
13360 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
13362 tree
13364 tree args,
13365 tsubst_flags_t complain,
13366 tree in_decl,
13369 {
13370 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
13371 #define RECUR(NODE) \
13372 tsubst_copy_and_build (NODE, args, complain, in_decl, \
13374 integral_constant_expression_p)
13377 location_t loc;
13387 {
13390 /* Fall through. */
13392 {
13393 tree decl;
13394 cp_id_kind idk;
13399 {
13402 }
13404 /* Look up the name. */
13407 /* By convention, expressions use ERROR_MARK_NODE to indicate
13408 failure, not NULL_TREE. */
13414 integral_constant_expression_p,
13422 input_location);
13426 {
13430 }
13432 }
13435 {
13436 tree object;
13444 {
13447 }
13448 else
13455 else
13457 }
13460 {
13464 {
13465 /* A type conversion to reference type will be enclosed in
13466 such an indirect ref, but the substitution of the cast
13467 will have also added such an indirect ref. */
13470 }
13471 else
13474 }
13482 {
13489 flags));
13490 }
13503 {
13504 tree type;
13510 {
13515 }
13521 {
13539 }
13543 }
13575 else
13577 in_decl);
13611 {
13612 tree r;
13616 r = build_x_binary_op
13620 ? ERROR_MARK
13624 ? ERROR_MARK
13627 complain);
13634 }
13648 /* Fall through */
13651 {
13652 tree r;
13658 {
13659 /* When there are no ARGS, we are trying to evaluate a
13660 non-dependent expression from the parser. Trying to do
13661 the substitutions may not work. */
13664 }
13665 else
13666 {
13671 else
13674 /*integral_constant_expression_p=*/
13678 }
13682 else
13686 {
13688 {
13690 {
13694 }
13695 else
13699 }
13701 }
13703 }
13706 {
13716 }
13730 {
13731 tree r = build_x_modify_expr
13736 complain);
13737 /* TREE_NO_WARNING must be set if either the expression was
13738 parenthesized or it uses an operator such as >>= rather
13739 than plain assignment. In the former case, it was already
13740 set and must be copied. In the latter case,
13741 build_x_modify_expr sets it and it must not be reset
13742 here. */
13746 }
13751 /* Remember that there was a reference to this entity. */
13757 {
13762 tree ret;
13766 else
13767 {
13771 }
13773 /* If there was an initializer in the original tree, but it
13774 instantiated to an empty list, then we should pass a
13775 non-NULL empty vector to tell build_new that it was an
13776 empty initializer() rather than no initializer. This can
13777 only happen when the initializer is a pack expansion whose
13778 parameter packs are of length zero. */
13781 else
13782 {
13786 else
13787 {
13790 }
13791 }
13798 complain);
13806 }
13814 complain));
13820 complain));
13823 {
13824 tree function;
13829 tree ret;
13832 /* When we parsed the expression, we determined whether or
13833 not Koenig lookup should be performed. */
13836 {
13841 }
13843 {
13844 /* Do nothing; calling tsubst_copy_and_build on an identifier
13845 would incorrectly perform unqualified lookup again.
13847 Note that we can also have an IDENTIFIER_NODE if the earlier
13848 unqualified lookup found a member function; in that case
13849 koenig_p will be false and we do want to do the lookup
13850 again to find the instantiated member function.
13852 FIXME but doing that causes c++/15272, so we need to stop
13853 using IDENTIFIER_NODE in that situation. */
13855 }
13856 else
13857 {
13859 {
13865 }
13866 else
13871 /* Avoid error about taking the address of a constructor. */
13875 in_decl,
13877 integral_constant_expression_p);
13881 }
13886 {
13891 else
13892 {
13893 /* Expand the pack expansion and push each entry onto
13894 CALL_ARGS. */
13897 {
13902 {
13907 }
13908 }
13909 else
13910 {
13911 /* A partial substitution. Add one entry. */
13913 }
13914 }
13915 }
13917 /* We do not perform argument-dependent lookup if normal
13918 lookup finds a non-function, in accordance with the
13919 expected resolution of DR 218. */
13922 /* If lookup found a member function, the Koenig lookup is
13923 not appropriate, even if an unqualified-name was used
13924 to denote the function. */
13927 /* Only do this when substitution turns a dependent call
13928 into a non-dependent call. */
13932 tf_none);
13936 {
13938 {
13939 /* For backwards compatibility and good diagnostics, try
13940 the unqualified lookup again if we aren't in SFINAE
13941 context. */
13942 tree unq = (tsubst_copy_and_build
13944 integral_constant_expression_p));
13949 {
13958 "%qD was not declared in this scope, "
13959 "and no declarations were found by "
13960 "argument-dependent lookup at the point "
13965 {
13967 "declarations in dependent base %qT are "
13973 else
13977 }
13978 else
13982 }
13983 }
13985 {
13990 }
13991 }
13993 /* Remember that there was a reference to this entity. */
13999 complain);
14001 {
14016 complain);
14017 else
14018 ret = (build_new_method_call
14023 complain));
14024 }
14025 else
14028 koenig_p,
14029 complain);
14034 }
14037 {
14042 {
14044 {
14049 }
14050 else
14051 {
14056 }
14057 }
14058 else
14059 {
14062 }
14066 }
14075 {
14083 {
14084 /* We have pack expansions, so expand those and
14085 create a new list out of it. */
14088 tree chain;
14091 /* Expand the argument expressions. */
14099 /* Build the rest of the list. */
14104 /* Determine the number of arguments. */
14106 {
14109 }
14112 else
14113 {
14114 /* Since we only performed a partial substitution into
14115 the argument pack, we only RETURN (a single list
14116 node. */
14123 }
14125 /* Convert the argument vectors into a TREE_LIST */
14128 {
14129 /* Grab the Ith values. */
14130 i--;
14133 value
14137 /* Build the list (backwards). */
14139 }
14142 }
14158 }
14161 {
14162 tree object;
14163 tree object_type;
14164 tree member;
14168 /* Remember that there was a reference to this entity. */
14178 else
14186 {
14188 {
14193 {
14196 }
14198 {
14202 }
14203 }
14204 }
14207 {
14208 /* Lookup the template functions now that we know what the
14209 scope is. */
14217 {
14220 args);
14221 member = (adjust_result_of_qualified_name_lookup
14223 object_type));
14224 }
14225 else
14226 {
14228 input_location);
14230 }
14231 }
14235 {
14237 {
14241 else
14244 }
14246 }
14252 complain));
14253 }
14260 {
14268 tree r;
14273 /* digest_init will do the wrong thing if we let it. */
14277 /* We do not want to process the index of aggregate
14278 initializers as they are identifier nodes which will be
14279 looked up by digest_init. */
14285 {
14290 {
14291 /* Substitute into the pack expansion. */
14293 in_decl);
14297 ;
14299 /* Just move the argument into place. */
14301 else
14302 {
14303 /* Update the length of the final CONSTRUCTOR
14304 arguments vector, and note that we will need to
14305 copy.*/
14308 }
14309 }
14310 else
14312 }
14315 {
14320 {
14322 {
14327 }
14328 else
14330 }
14331 }
14341 }
14344 {
14347 {
14350 }
14351 else
14352 {
14355 }
14356 }
14361 /* Fall through */
14364 {
14368 /* If the original type was a reference, we'll be wrapped in
14369 the appropriate INDIRECT_REF. */
14372 }
14383 {
14392 }
14395 {
14401 integral_constant_expression_p);
14405 /* If the resulting list of expression statement is empty,
14406 fold it further into void_zero_node. */
14411 }
14414 {
14428 /* For a function scope, we want to use tsubst so that we don't
14429 complain about referring to an auto function before its return
14430 type has been deduced. Otherwise, we want to use tsubst_copy so
14431 that we look up the existing field/parameter/variable rather
14432 than build a new one. */
14437 else
14446 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
14448 /* Now that we know visibility, instantiate the type so we have a
14449 declaration of the op() for later calls to lambda_function. */
14452 /* The capture list refers to closure members, so this needs to
14453 wait until after we finish instantiating the type. */
14459 }
14462 /* We can get here for a constant initializer of non-dependent type.
14463 FIXME stop folding in cp_parser_initializer_clause. */
14464 {
14466 complain);
14468 }
14472 integral_constant_expression_p));
14475 /* Handle Objective-C++ constructs, if appropriate. */
14476 {
14477 tree subst
14482 }
14484 }
14486 #undef RECUR
14487 #undef RETURN
14488 out:
14491 }
14493 /* Verify that the instantiated ARGS are valid. For type arguments,
14494 make sure that the type's linkage is ok. For non-type arguments,
14495 make sure they are constants if they are integral or enumerations.
14496 Emit an error under control of COMPLAIN, and return TRUE on error. */
14498 static bool
14500 {
14504 {
14514 }
14516 {
14517 /* [basic.link]: A name with no linkage (notably, the name
14518 of a class or enumeration declared in a local scope)
14519 shall not be used to declare an entity with linkage.
14520 This implies that names with no linkage cannot be used as
14521 template arguments
14523 DR 757 relaxes this restriction for C++0x. */
14528 {
14529 /* DR 488 makes use of a type with no linkage cause
14530 type deduction to fail. */
14532 {
14535 else
14538 }
14540 }
14541 /* In order to avoid all sorts of complications, we do not
14542 allow variably-modified types as template arguments. */
14544 {
14548 }
14549 }
14550 /* Class template and alias template arguments should be OK. */
14552 ;
14553 /* A non-type argument of integral or enumerated type must be a
14554 constant. */
14558 {
14562 }
14564 }
14566 static bool
14568 {
14573 {
14576 }
14580 }
14582 /* We're out of SFINAE context now, so generate diagnostics for the access
14583 errors we saw earlier when instantiating D from TMPL and ARGS. */
14585 static void
14587 {
14599 }
14601 /* Instantiate the indicated variable, function, or alias template TMPL with
14602 the template arguments in TARG_PTR. */
14604 static tree
14606 {
14608 tree fndecl;
14609 tree gen_tmpl;
14610 tree spec;
14618 /* If this function is a clone, handle it specially. */
14620 {
14621 tree spec;
14622 tree clone;
14624 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
14625 DECL_CLONED_FUNCTION. */
14631 /* Look for the clone. */
14635 /* We should always have found the clone by now. */
14638 }
14640 /* Check to see if we already have this specialization. */
14643 /* The TMPL is a partial instantiation. To get a full set of
14644 arguments we must add the arguments used to perform the
14645 partial instantiation. */
14647 targ_ptr);
14649 /* It would be nice to avoid hashing here and then again in tsubst_decl,
14650 but it doesn't seem to be on the hot path. */
14659 {
14661 {
14665 }
14667 }
14670 complain))
14673 /* We are building a FUNCTION_DECL, during which the access of its
14674 parameters and return types have to be checked. However this
14675 FUNCTION_DECL which is the desired context for access checking
14676 is not built yet. We solve this chicken-and-egg problem by
14677 deferring all checks until we have the FUNCTION_DECL. */
14680 /* Instantiation of the function happens in the context of the function
14681 template, not the context of the overload resolution we're doing. */
14683 /* If there are dependent arguments, e.g. because we're doing partial
14684 ordering, make sure processing_template_decl stays set. */
14688 {
14692 }
14693 /* Substitute template parameters to obtain the specialization. */
14701 {
14704 }
14706 /* The DECL_TI_TEMPLATE should always be the immediate parent
14707 template, not the most general template. */
14710 /* Now we know the specialization, compute access previously
14711 deferred. */
14718 /* If we've just instantiated the main entry point for a function,
14719 instantiate all the alternate entry points as well. We do this
14720 by cloning the instantiation of the main entry point, not by
14721 instantiating the template clones. */
14726 {
14728 {
14729 /* Remember to reinstantiate when we're out of SFINAE so the user
14730 can see the errors. */
14732 }
14734 }
14736 }
14738 /* Wrapper for instantiate_template_1. */
14740 tree
14742 {
14743 tree ret;
14748 }
14750 /* Instantiate the alias template TMPL with ARGS. Also push a template
14751 instantiation level, which instantiate_template doesn't do because
14752 functions and variables have sufficient context established by the
14753 callers. */
14755 static tree
14757 {
14764 {
14767 }
14769 args =
14777 /* We can't free this if a pending_template entry or last_error_tinst_level
14778 is pointing at it. */
14784 }
14786 /* PARM is a template parameter pack for FN. Returns true iff
14787 PARM is used in a deducible way in the argument list of FN. */
14789 static bool
14791 {
14794 {
14796 tree packs;
14802 {
14803 /* The template parameter pack is used in a function parameter
14804 pack. If this is the end of the parameter list, the
14805 template parameter pack is deducible. */
14808 else
14809 /* Otherwise, not. Well, it could be deduced from
14810 a non-pack parameter, but doing so would end up with
14811 a deduction mismatch, so don't bother. */
14813 }
14814 }
14815 /* The template parameter pack isn't used in any function parameter
14816 packs, but it might be used deeper, e.g. tuple<Args...>. */
14818 }
14820 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
14821 NARGS elements of the arguments that are being used when calling
14822 it. TARGS is a vector into which the deduced template arguments
14823 are placed.
14825 Return zero for success, 2 for an incomplete match that doesn't resolve
14826 all the types, and 1 for complete failure. An error message will be
14827 printed only for an incomplete match.
14829 If FN is a conversion operator, or we are trying to produce a specific
14830 specialization, RETURN_TYPE is the return type desired.
14832 The EXPLICIT_TARGS are explicit template arguments provided via a
14833 template-id.
14835 The parameter STRICT is one of:
14837 DEDUCE_CALL:
14838 We are deducing arguments for a function call, as in
14839 [temp.deduct.call].
14841 DEDUCE_CONV:
14842 We are deducing arguments for a conversion function, as in
14843 [temp.deduct.conv].
14845 DEDUCE_EXACT:
14846 We are deducing arguments when doing an explicit instantiation
14847 as in [temp.explicit], when determining an explicit specialization
14848 as in [temp.expl.spec], or when taking the address of a function
14849 template, as in [temp.deduct.funcaddr]. */
14851 tree
14853 tree explicit_targs,
14854 tree targs,
14857 tree return_type,
14858 unification_kind_t strict,
14861 {
14862 tree parms;
14863 tree fntype;
14871 tree tinst;
14874 /* Adjust any explicit template arguments before entering the
14875 substitution context. */
14877 {
14878 explicit_targs
14880 complain,
14885 }
14887 /* In C++0x, it's possible to have a function template whose type depends
14888 on itself recursively. This is most obvious with decltype, but can also
14889 occur with enumeration scope (c++/48969). So we need to catch infinite
14890 recursion and reject the substitution at deduction time; this function
14891 will return error_mark_node for any repeated substitution.
14893 This also catches excessive recursion such as when f<N> depends on
14894 f<N-1> across all integers, and returns error_mark_node for all the
14895 substitutions back up to the initial one.
14897 This is, of course, not reentrant. */
14902 {
14906 }
14914 {
14915 /* [temp.deduct]
14917 The specified template arguments must match the template
14918 parameters in kind (i.e., type, nontype, template), and there
14919 must not be more arguments than there are parameters;
14920 otherwise type deduction fails.
14922 Nontype arguments must match the types of the corresponding
14923 nontype template parameters, or must be convertible to the
14924 types of the corresponding nontype parameters as specified in
14925 _temp.arg.nontype_, otherwise type deduction fails.
14927 All references in the function type of the function template
14928 to the corresponding template parameters are replaced by the
14929 specified template argument values. If a substitution in a
14930 template parameter or in the function type of the function
14931 template results in an invalid type, type deduction fails. */
14936 /* Substitute the explicit args into the function type. This is
14937 necessary so that, for instance, explicitly declared function
14938 arguments can match null pointed constants. If we were given
14939 an incomplete set of explicit args, we must not do semantic
14940 processing during substitution as we could create partial
14941 instantiations. */
14943 {
14948 /* Dig out the actual parm. */
14951 {
14954 }
14956 {
14959 }
14962 /* No explicit argument for this template parameter. */
14966 {
14967 /* Mark the argument pack as "incomplete". We could
14968 still deduce more arguments during unification.
14969 We remove this mark in type_unification_real. */
14971 {
14975 }
14977 /* We have some incomplete argument packs. */
14979 }
14980 }
14992 /* Place the explicitly specified arguments in TARGS. */
14995 }
14997 /* Never do unification on the 'this' parameter. */
15001 {
15010 }
15012 /* We allow incomplete unification without an error message here
15013 because the standard doesn't seem to explicitly prohibit it. Our
15014 callers must be ready to deal with unification failures in any
15015 event. */
15025 /* Now that we have bindings for all of the template arguments,
15026 ensure that the arguments deduced for the template template
15027 parameters have compatible template parameter lists. We cannot
15028 check this property before we have deduced all template
15029 arguments, because the template parameter types of a template
15030 template parameter might depend on prior template parameters
15031 deduced after the template template parameter. The following
15032 ill-formed example illustrates this issue:
15034 template<typename T, template<T> class C> void f(C<5>, T);
15036 template<int N> struct X {};
15038 void g() {
15039 f(X<5>(), 5l); // error: template argument deduction fails
15040 }
15042 The template parameter list of 'C' depends on the template type
15043 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
15044 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
15045 time that we deduce 'C'. */
15048 {
15051 }
15053 /* All is well so far. Now, check:
15055 [temp.deduct]
15057 When all template arguments have been deduced, all uses of
15058 template parameters in nondeduced contexts are replaced with
15059 the corresponding deduced argument values. If the
15060 substitution results in an invalid type, as described above,
15061 type deduction fails. */
15066 /* Now perform any access checks encountered during deduction, such as
15067 for default template arguments. */
15074 /* If we're looking for an exact match, check that what we got
15075 is indeed an exact match. It might not be if some template
15076 parameters are used in non-deduced contexts. */
15078 {
15082 tree sarg
15088 {
15092 }
15093 }
15097 fail:
15101 {
15103 /* Reset once we're all the way out. */
15105 }
15108 /* We can't free this if a pending_template entry or last_error_tinst_level
15109 is pointing at it. */
15115 }
15117 /* Adjust types before performing type deduction, as described in
15118 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
15119 sections are symmetric. PARM is the type of a function parameter
15120 or the return type of the conversion function. ARG is the type of
15121 the argument passed to the call, or the type of the value
15122 initialized with the result of the conversion function.
15123 ARG_EXPR is the original argument expression, which may be null. */
15125 static int
15129 tree arg_expr)
15130 {
15134 {
15139 {
15140 /* Swap PARM and ARG throughout the remainder of this
15141 function; the handling is precisely symmetric since PARM
15142 will initialize ARG rather than vice versa. */
15147 }
15150 /* Core issue #873: Do the DR606 thing (see below) for these cases,
15151 too, but here handle it by stripping the reference from PARM
15152 rather than by adding it to ARG. */
15160 /* Nothing else to do in this case. */
15165 }
15168 {
15169 /* [temp.deduct.call]
15171 If P is not a reference type:
15173 --If A is an array type, the pointer type produced by the
15174 array-to-pointer standard conversion (_conv.array_) is
15175 used in place of A for type deduction; otherwise,
15177 --If A is a function type, the pointer type produced by
15178 the function-to-pointer standard conversion
15179 (_conv.func_) is used in place of A for type deduction;
15180 otherwise,
15182 --If A is a cv-qualified type, the top level
15183 cv-qualifiers of A's type are ignored for type
15184 deduction. */
15189 else
15191 }
15193 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
15194 of the form T&&, where T is a template parameter, and the argument
15195 is an lvalue, T is deduced as A& */
15201 /* try_one_overload doesn't provide an arg_expr, but
15202 functions are always lvalues. */
15206 /* [temp.deduct.call]
15208 If P is a cv-qualified type, the top level cv-qualifiers
15209 of P's type are ignored for type deduction. If P is a
15210 reference type, the type referred to by P is used for
15211 type deduction. */
15214 {
15217 }
15219 /* DR 322. For conversion deduction, remove a reference type on parm
15220 too (which has been swapped into ARG). */
15225 }
15227 /* Subroutine of unify_one_argument. PARM is a function parameter of a
15228 template which does contain any deducible template parameters; check if
15229 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
15230 unify_one_argument. */
15232 static int
15235 {
15236 tree type;
15240 else
15247 {
15251 }
15253 {
15258 }
15262 else
15264 }
15266 /* Subroutine of type_unification_real and unify_pack_expansion to
15267 handle unification of a single P/A pair. Parameters are as
15268 for those functions. */
15270 static int
15274 {
15281 /* We can't deduce anything from this, but we might get all the
15282 template args from other function args. */
15285 /* FIXME uses_deducible_template_parms */
15288 explain_p);
15291 {
15293 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
15294 | UNIFY_ALLOW_MORE_CV_QUAL
15308 }
15310 /* We only do these transformations if this is the top-level
15311 parameter_type_list in a call or declaration matching; in other
15312 situations (nested function declarators, template argument lists) we
15313 won't be comparing a type to an expression, and we don't do any type
15314 adjustments. */
15316 {
15318 {
15321 {
15322 /* [temp.deduct.type] A template-argument can be
15323 deduced from a pointer to function or pointer
15324 to member function argument if the set of
15325 overloaded functions does not contain function
15326 templates and at most one of a set of
15327 overloaded functions provides a unique
15328 match. */
15335 }
15341 }
15343 arg_strict |=
15345 }
15346 else
15350 /* For deduction from an init-list we need the actual list. */
15354 }
15356 /* Most parms like fn_type_unification.
15358 If SUBR is 1, we're being called recursively (to unify the
15359 arguments of a function or method parameter of a function
15360 template). */
15362 static int
15364 tree targs,
15365 tree xparms,
15369 unification_kind_t strict,
15372 {
15377 tree parms;
15386 /* Reset the number of non-defaulted template arguments contained
15387 in TARGS. */
15390 again:
15398 {
15403 /* For a function parameter pack that occurs at the end of the
15404 parameter-declaration-list, the type A of each remaining
15405 argument of the call is compared with the type P of the
15406 declarator-id of the function parameter pack. */
15412 /* For a function parameter pack that does not occur at the
15413 end of the parameter-declaration-list, the type of the
15414 parameter pack is a non-deduced context. */
15423 }
15428 {
15429 /* Unify the remaining arguments with the pack expansion type. */
15430 tree argvec;
15433 /* Allocate a TREE_VEC and copy in all of the arguments */
15438 /* Copy the parameter into parmvec. */
15444 /* Advance to the end of the list of parameters. */
15446 }
15448 /* Fail if we've reached the end of the parm list, and more args
15449 are present, and the parm list isn't variadic. */
15452 /* Fail if parms are left and they don't have default values. */
15455 {
15459 {
15460 count++;
15462 }
15464 }
15467 {
15468 tsubst_flags_t complain = (explain_p
15469 ? tf_warning_or_error
15473 {
15477 /* Clear the "incomplete" flags on all argument packs now so that
15478 substituting them into later default arguments works. */
15480 {
15483 }
15489 /* If this is an undeduced nontype parameter that depends on
15490 a type parameter, try another pass; its type may have been
15491 deduced from a later argument than the one from which
15492 this parameter can be deduced. */
15498 /* Core issue #226 (C++0x) [temp.deduct]:
15500 If a template argument has not been deduced, its
15501 default template argument, if any, is used.
15503 When we are in C++98 mode, TREE_PURPOSE will either
15504 be NULL_TREE or ERROR_MARK_NODE, so we do not need
15505 to explicitly check cxx_dialect here. */
15507 {
15519 else
15520 {
15522 /* The position of the first default template argument,
15523 is also the number of non-defaulted arguments in TARGS.
15524 Record that. */
15528 }
15529 }
15531 /* If the type parameter is a parameter pack, then it will
15532 be deduced to an empty parameter pack. */
15534 {
15535 tree arg;
15538 {
15542 }
15543 else
15550 }
15553 }
15554 }
15555 #ifdef ENABLE_CHECKING
15558 #endif
15561 }
15563 /* Subroutine of type_unification_real. Args are like the variables
15564 at the call site. ARG is an overloaded function (or template-id);
15565 we try deducing template args from each of the overloads, and if
15566 only one succeeds, we go with that. Modifies TARGS and returns
15567 true on success. */
15569 static bool
15571 tree targs,
15572 tree parm,
15573 tree arg,
15574 unification_kind_t strict,
15577 {
15584 {
15587 }
15588 else
15592 /* Handle `&x' where `x' is some static or non-static member
15593 function name. */
15599 /* Strip baselink information. */
15604 {
15605 /* If we got some explicit template args, we need to plug them into
15606 the affected templates before we try to unify, in case the
15607 explicit args will completely resolve the templates in question. */
15614 {
15627 {
15632 {
15635 }
15636 }
15639 }
15640 /* If no templates (or more than one) are fully resolved by the
15641 explicit arguments, this template-id is a non-deduced context; it
15642 could still be OK if we deduce all template arguments for the
15643 enclosing call through other arguments. */
15646 }
15649 /* If ARG is, for example, "(0, &f)" then its type will be unknown
15650 -- but the deduction does not succeed because the expression is
15651 not just the function on its own. */
15653 else
15659 {
15662 }
15664 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15665 to function or pointer to member function argument if the set of
15666 overloaded functions does not contain function templates and at most
15667 one of a set of overloaded functions provides a unique match.
15669 So if we found multiple possibilities, we return success but don't
15670 deduce anything. */
15673 {
15678 }
15683 }
15685 /* Core DR 115: In contexts where deduction is done and fails, or in
15686 contexts where deduction is not done, if a template argument list is
15687 specified and it, along with any default template arguments, identifies
15688 a single function template specialization, then the template-id is an
15689 lvalue for the function template specialization. */
15691 tree
15693 {
15706 {
15709 }
15711 {
15714 }
15716 {
15719 }
15722 {
15726 /* If we got some explicit template args, we need to plug them into
15727 the affected templates before we try to unify, in case the
15728 explicit args will completely resolve the templates in question. */
15736 {
15749 {
15752 {
15755 }
15757 {
15760 }
15761 }
15762 }
15764 {
15772 {
15773 tree base
15776 }
15780 }
15782 /* There were no good options and at least one bad one, so let the
15783 user know what the problem is. */
15785 }
15787 }
15789 /* Subroutine of resolve_overloaded_unification; does deduction for a single
15790 overload. Fills TARGS with any deduced arguments, or error_mark_node if
15791 different overloads deduce different arguments for a given parm.
15792 ADDR_P is true if the expression for which deduction is being
15793 performed was of the form "& fn" rather than simply "fn".
15795 Returns 1 on success. */
15797 static int
15799 tree orig_targs,
15800 tree targs,
15801 tree parm,
15802 tree arg,
15803 unification_kind_t strict,
15807 {
15809 tree tempargs;
15815 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15816 to function or pointer to member function argument if the set of
15817 overloaded functions does not contain function templates and at most
15818 one of a set of overloaded functions provides a unique match.
15820 So if this is a template, just return success. */
15832 /* We don't copy orig_targs for this because if we have already deduced
15833 some template args from previous args, unify would complain when we
15834 try to deduce a template parameter for the same argument, even though
15835 there isn't really a conflict. */
15842 /* First make sure we didn't deduce anything that conflicts with
15843 explicitly specified args. */
15845 {
15852 /* Since we're unifying against ourselves, we will fill in
15853 template args used in the function parm list with our own
15854 template parms. Discard them. */
15858 }
15861 {
15866 }
15869 }
15871 /* PARM is a template class (perhaps with unbound template
15872 parameters). ARG is a fully instantiated type. If ARG can be
15873 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
15874 TARGS are as for unify. */
15876 static tree
15879 {
15880 tree copy_of_targs;
15887 /* We need to make a new template argument vector for the call to
15888 unify. If we used TARGS, we'd clutter it up with the result of
15889 the attempted unification, even if this class didn't work out.
15890 We also don't want to commit ourselves to all the unifications
15891 we've already done, since unification is supposed to be done on
15892 an argument-by-argument basis. In other words, consider the
15893 following pathological case:
15895 template <int I, int J, int K>
15896 struct S {};
15898 template <int I, int J>
15899 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
15901 template <int I, int J, int K>
15902 void f(S<I, J, K>, S<I, I, I>);
15904 void g() {
15905 S<0, 0, 0> s0;
15906 S<0, 1, 2> s2;
15908 f(s0, s2);
15909 }
15911 Now, by the time we consider the unification involving `s2', we
15912 already know that we must have `f<0, 0, 0>'. But, even though
15913 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
15914 because there are two ways to unify base classes of S<0, 1, 2>
15915 with S<I, I, I>. If we kept the already deduced knowledge, we
15916 would reject the possibility I=1. */
15919 /* If unification failed, we're done. */
15925 }
15927 /* Given a template type PARM and a class type ARG, find the unique
15928 base type in ARG that is an instance of PARM. We do not examine
15929 ARG itself; only its base-classes. If there is not exactly one
15930 appropriate base class, return NULL_TREE. PARM may be the type of
15931 a partial specialization, as well as a plain template type. Used
15932 by unify. */
15934 static enum template_base_result
15937 {
15939 tree binfo;
15945 {
15946 /* The type could not be completed. */
15949 }
15951 /* Walk in inheritance graph order. The search order is not
15952 important, and this avoids multiple walks of virtual bases. */
15954 {
15959 {
15960 /* If there is more than one satisfactory baseclass, then:
15962 [temp.deduct.call]
15964 If they yield more than one possible deduced A, the type
15965 deduction fails.
15967 applies. */
15969 {
15972 }
15975 }
15976 }
15980 }
15982 /* Returns the level of DECL, which declares a template parameter. */
15984 static int
15986 {
15988 {
15998 }
16000 }
16002 /* Decide whether ARG can be unified with PARM, considering only the
16003 cv-qualifiers of each type, given STRICT as documented for unify.
16004 Returns nonzero iff the unification is OK on that basis. */
16006 static int
16008 {
16014 {
16015 /* Although a CVR qualifier is ignored when being applied to a
16016 substituted template parameter ([8.3.2]/1 for example), that
16017 does not allow us to unify "const T" with "int&" because both
16018 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
16019 It is ok when we're allowing additional CV qualifiers
16020 at the outer level [14.8.2.1]/3,1st bullet. */
16030 }
16041 }
16043 /* Determines the LEVEL and INDEX for the template parameter PARM. */
16044 void
16046 {
16050 {
16053 }
16054 else
16055 {
16058 }
16059 }
16061 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
16062 do { \
16063 if (unify (TP, TA, P, A, S, EP)) \
16064 return 1; \
16065 } while (0);
16067 /* Unifies the remaining arguments in PACKED_ARGS with the pack
16068 expansion at the end of PACKED_PARMS. Returns 0 if the type
16069 deduction succeeds, 1 otherwise. STRICT is the same as in
16070 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
16071 call argument list. We'll need to adjust the arguments to make them
16072 types. SUBR tells us if this is from a recursive call to
16073 type_unification_real, or for comparing two template argument
16074 lists. */
16076 static int
16080 {
16081 tree parm
16088 /* Determine the parameter packs we will be deducing from the
16089 pattern, and record their current deductions. */
16092 {
16096 /* Determine the index and level of this parameter pack. */
16099 /* Keep track of the parameter packs and their corresponding
16100 argument packs. */
16103 }
16105 /* Loop through all of the arguments that have not yet been
16106 unified and unify each with the pattern. */
16108 {
16109 tree parm;
16113 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
16114 or the element of its argument pack at the current index if
16115 this argument was explicitly specified. */
16117 {
16126 {
16129 }
16131 }
16133 /* If we had explicit template arguments, substitute them into the
16134 pattern before deduction. */
16136 {
16137 /* Some arguments might still be unspecified or dependent. */
16145 NULL_TREE);
16150 }
16151 else
16154 /* Unify the pattern with the current argument. */
16159 /* For each parameter pack, collect the deduced value. */
16161 {
16167 }
16168 }
16170 /* Verify that the results of unification with the parameter packs
16171 produce results consistent with what we've seen before, and make
16172 the deduced argument packs available. */
16174 {
16181 /* By default keep the original deduced argument pack.
16182 If necessary, more specific code is going to update the
16183 resulting deduced argument later down in this function. */
16187 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
16188 actually deduce anything. */
16196 {
16197 /* If we had fewer function args than explicit template args,
16198 just use the explicits. */
16203 }
16206 {
16207 tree result;
16208 /* Build the deduced *_ARGUMENT_PACK. */
16210 {
16215 }
16216 else
16221 /* Note the deduced argument packs for this parameter
16222 pack. */
16224 }
16228 {
16229 /* We only had the explicitly-provided arguments before, but
16230 now we have a complete set of arguments. */
16236 }
16237 else
16238 {
16244 /* Inconsistent unification of this parameter pack. */
16246 bad_old_arg,
16247 bad_new_arg);
16248 }
16249 }
16252 }
16254 /* Deduce the value of template parameters. TPARMS is the (innermost)
16255 set of template parameters to a template. TARGS is the bindings
16256 for those template parameters, as determined thus far; TARGS may
16257 include template arguments for outer levels of template parameters
16258 as well. PARM is a parameter to a template function, or a
16259 subcomponent of that parameter; ARG is the corresponding argument.
16260 This function attempts to match PARM with ARG in a manner
16261 consistent with the existing assignments in TARGS. If more values
16262 are deduced, then TARGS is updated.
16264 Returns 0 if the type deduction succeeds, 1 otherwise. The
16265 parameter STRICT is a bitwise or of the following flags:
16267 UNIFY_ALLOW_NONE:
16268 Require an exact match between PARM and ARG.
16269 UNIFY_ALLOW_MORE_CV_QUAL:
16270 Allow the deduced ARG to be more cv-qualified (by qualification
16271 conversion) than ARG.
16272 UNIFY_ALLOW_LESS_CV_QUAL:
16273 Allow the deduced ARG to be less cv-qualified than ARG.
16274 UNIFY_ALLOW_DERIVED:
16275 Allow the deduced ARG to be a template base class of ARG,
16276 or a pointer to a template base class of the type pointed to by
16277 ARG.
16278 UNIFY_ALLOW_INTEGER:
16279 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
16280 case for more information.
16281 UNIFY_ALLOW_OUTER_LEVEL:
16282 This is the outermost level of a deduction. Used to determine validity
16283 of qualification conversions. A valid qualification conversion must
16284 have const qualified pointers leading up to the inner type which
16285 requires additional CV quals, except at the outer level, where const
16286 is not required [conv.qual]. It would be normal to set this flag in
16287 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
16288 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
16289 This is the outermost level of a deduction, and PARM can be more CV
16290 qualified at this point.
16291 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
16292 This is the outermost level of a deduction, and PARM can be less CV
16293 qualified at this point. */
16295 static int
16298 {
16300 tree targ;
16301 tree tparm;
16304 /* I don't think this will do the right thing with respect to types.
16305 But the only case I've seen it in so far has been array bounds, where
16306 signedness is the only information lost, and I think that will be
16307 okay. */
16315 /* We can't deduce anything from this, but we might get all the
16316 template args from other function args. */
16319 /* If PARM uses template parameters, then we can't bail out here,
16320 even if ARG == PARM, since we won't record unifications for the
16321 template parameters. We might need them if we're trying to
16322 figure out which of two things is more specialized. */
16326 /* Handle init lists early, so the rest of the function can assume
16327 we're dealing with a type. */
16329 {
16334 /* Replace T with std::initializer_list<T> for deduction. */
16340 /* We can only deduce from an initializer list argument if the
16341 parameter is std::initializer_list; otherwise this is a
16342 non-deduced context. */
16348 {
16355 {
16357 /* It should only be possible to get here for a call. */
16359 elt_strict |= maybe_adjust_types_for_deduction
16362 }
16365 explain_p);
16366 }
16368 /* If the std::initializer_list<T> deduction worked, replace the
16369 deduced A with std::initializer_list<A>. */
16371 {
16376 }
16378 }
16380 /* Immediately reject some pairs that won't unify because of
16381 cv-qualification mismatches. */
16384 /* It is the elements of the array which hold the cv quals of an array
16385 type, and the elements might be template type parms. We'll check
16386 when we recurse. */
16388 /* We check the cv-qualifiers when unifying with template type
16389 parameters below. We want to allow ARG `const T' to unify with
16390 PARM `T' for example, when computing which of two templates
16391 is more specialized, for example. */
16405 {
16409 /* In a type which contains a nested-name-specifier, template
16410 argument values cannot be deduced for template parameters used
16411 within the nested-name-specifier. */
16423 /* The PARM is not one we're trying to unify. Just check
16424 to see if it matches ARG. */
16425 {
16430 else
16432 }
16439 /* Check for mixed types and values. */
16447 {
16448 /* ARG must be constructed from a template class or a template
16449 template parameter. */
16454 {
16458 tree parm_parms
16459 = DECL_INNERMOST_TEMPLATE_PARMS
16464 /* The resolution to DR150 makes clear that default
16465 arguments for an N-argument may not be used to bind T
16466 to a template template parameter with fewer than N
16467 parameters. It is not safe to permit the binding of
16468 default arguments as an extension, as that may change
16469 the meaning of a conforming program. Consider:
16471 struct Dense { static const unsigned int dim = 1; };
16473 template <template <typename> class View,
16474 typename Block>
16475 void operator+(float, View<Block> const&);
16477 template <typename Block,
16478 unsigned int Dim = Block::dim>
16479 struct Lvalue_proxy { operator float() const; };
16481 void
16482 test_1d (void) {
16483 Lvalue_proxy<Dense> p;
16484 float b;
16485 b + p;
16486 }
16488 Here, if Lvalue_proxy is permitted to bind to View, then
16489 the global operator+ will be used; if they are not, the
16490 Lvalue_proxy will be converted to float. */
16492 full_argvec,
16494 (explain_p
16495 ? tf_warning_or_error
16502 /* Deduce arguments T, i from TT<T> or TT<i>.
16503 We check each element of PARMVEC and ARGVEC individually
16504 rather than the whole TREE_VEC since they can have
16505 different number of elements. */
16512 /* Check if the parameters end in a pack, making them
16513 variadic. */
16523 {
16528 }
16533 DEDUCE_EXACT,
16536 }
16539 /* Fall through to deduce template name. */
16540 }
16544 {
16545 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
16547 /* Simple cases: Value already set, does match or doesn't. */
16552 }
16553 else
16554 {
16555 /* If PARM is `const T' and ARG is only `int', we don't have
16556 a match unless we are allowing additional qualification.
16557 If ARG is `const int' and PARM is just `T' that's OK;
16558 that binds `const int' to `T'. */
16563 /* Consider the case where ARG is `const volatile int' and
16564 PARM is `const T'. Then, T should be `volatile int'. */
16565 arg = cp_build_qualified_type_real
16570 /* Simple cases: Value already set, does match or doesn't. */
16576 /* Make sure that ARG is not a variable-sized array. (Note
16577 that were talking about variable-sized arrays (like
16578 `int[n]'), rather than arrays of unknown size (like
16579 `int[]').) We'll get very confused by such a type since
16580 the bound of the array is not constant, and therefore
16581 not mangleable. Besides, such types are not allowed in
16582 ISO C++, so we can do as we please here. We do allow
16583 them for 'auto' deduction, since that isn't ABI-exposed. */
16587 /* Strip typedefs as in convert_template_argument. */
16589 }
16591 /* If ARG is a parameter pack or an expansion, we cannot unify
16592 against it unless PARM is also a parameter pack. */
16597 /* If the argument deduction results is a METHOD_TYPE,
16598 then there is a problem.
16599 METHOD_TYPE doesn't map to any real C++ type the result of
16600 the deduction can not be of that type. */
16614 {
16615 /* The PARM is not one we're trying to unify. Just check
16616 to see if it matches ARG. */
16622 }
16628 {
16633 }
16635 /* [temp.deduct.type] If, in the declaration of a function template
16636 with a non-type template-parameter, the non-type
16637 template-parameter is used in an expression in the function
16638 parameter-list and, if the corresponding template-argument is
16639 deduced, the template-argument type shall match the type of the
16640 template-parameter exactly, except that a template-argument
16641 deduced from an array bound may be of any integral type.
16642 The non-type parameter might use already deduced type parameters. */
16645 /* Template-parameter dependent expression. Just accept it for now.
16646 It will later be processed in convert_template_argument. */
16647 ;
16653 /* Convert the ARG to the type of PARM; the deduced non-type
16654 template argument must exactly match the types of the
16655 corresponding parameter. */
16658 /* We haven't deduced the type of this parameter yet. Try again
16659 later. */
16661 else
16664 /* If ARG is a parameter pack or an expansion, we cannot unify
16665 against it unless PARM is also a parameter pack. */
16675 {
16676 /* A pointer-to-member constant can be unified only with
16677 another constant. */
16681 /* Just unify the class member. It would be useless (and possibly
16682 wrong, depending on the strict flags) to unify also
16683 PTRMEM_CST_CLASS, because we want to be sure that both parm and
16684 arg refer to the same variable, even if through different
16685 classes. For instance:
16687 struct A { int x; };
16688 struct B : A { };
16690 Unification of &A::x and &B::x must succeed. */
16693 }
16696 {
16700 /* [temp.deduct.call]
16702 A can be another pointer or pointer to member type that can
16703 be converted to the deduced A via a qualification
16704 conversion (_conv.qual_).
16706 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
16707 This will allow for additional cv-qualification of the
16708 pointed-to types if appropriate. */
16711 /* The derived-to-base conversion only persists through one
16712 level of pointers. */
16717 }
16734 {
16735 tree parm_max;
16736 tree arg_max;
16740 /* Our representation of array types uses "N - 1" as the
16741 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
16742 not an integer constant. We cannot unify arbitrarily
16743 complex expressions, so we eliminate the MINUS_EXPRs
16744 here. */
16748 {
16751 }
16755 {
16756 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
16757 trying to unify the type of a variable with the type
16758 of a template parameter. For example:
16760 template <unsigned int N>
16761 void f (char (&) [N]);
16762 int g();
16763 void h(int i) {
16764 char a[g(i)];
16765 f(a);
16766 }
16768 Here, the type of the ARG will be "int [g(i)]", and
16769 may be a SAVE_EXPR, etc. */
16773 }
16775 /* If only one of the bounds used a MINUS_EXPR, compensate
16776 by adding one to the other bound. */
16779 integer_type_node,
16780 parm_max,
16781 integer_one_node);
16784 integer_type_node,
16785 arg_max,
16786 integer_one_node);
16790 }
16804 /* We have already checked cv-qualification at the top of the
16805 function. */
16809 /* As far as unification is concerned, this wins. Later checks
16810 will invalidate it if necessary. */
16813 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
16814 /* Type INTEGER_CST can come from ordinary constant template args. */
16826 {
16836 /* Check for pack expansions in the parameters. */
16838 {
16840 {
16842 /* We can unify against something with a trailing
16843 parameter pack. */
16845 else
16846 /* [temp.deduct.type]/9: If the template argument list of
16847 P contains a pack expansion that is not the last
16848 template argument, the entire template argument list
16849 is a non-deduced context. */
16851 }
16852 }
16854 /* If we don't have enough arguments to satisfy the parameters
16855 (not counting the pack expression at the end), or we have
16856 too many arguments for a parameter list that doesn't end in
16857 a pack expression, we can't unify. */
16863 /* Unify all of the parameters that precede the (optional)
16864 pack expression. */
16866 {
16871 }
16874 DEDUCE_EXACT,
16877 }
16885 {
16893 }
16896 {
16900 {
16901 /* First, we try to unify the PARM and ARG directly. */
16906 {
16907 /* Fallback to the special case allowed in
16908 [temp.deduct.call]:
16910 If P is a class, and P has the form
16911 template-id, then A can be a derived class of
16912 the deduced A. Likewise, if P is a pointer to
16913 a class of the form template-id, A can be a
16914 pointer to a derived class pointed to by the
16915 deduced A. */
16922 }
16923 }
16927 /* Perhaps PARM is something like S<U> and ARG is S<int>.
16928 Then, we should unify `int' and `U'. */
16930 else
16931 /* There's no chance of unification succeeding. */
16936 }
16943 {
16946 tree a;
16952 /* CV qualifications for methods can never be deduced, they must
16953 match exactly. We need to check them explicitly here,
16954 because type_unification_real treats them as any other
16955 cv-qualified parameter. */
16957 && (!check_cv_quals_for_unify
16977 }
16980 /* Unify a pointer to member with a pointer to member function, which
16981 deduces the type of the member as a function type. */
16983 {
16984 tree method_type;
16985 tree fntype;
16987 /* Check top-level cv qualifiers */
16995 /* Determine the type of the function we are unifying against. */
16997 fntype =
17001 /* Extract the cv-qualifiers of the member function from the
17002 implicit object parameter and place them on the function
17003 type to be restored later. */
17006 }
17025 /* Matched cases are handled by the ARG == PARM test above. */
17029 /* A non-type template parameter that is a variable should be a
17030 an integral constant, in which case, it whould have been
17031 folded into its (constant) value. So we should not be getting
17032 a variable here. */
17043 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
17044 or UNDERLYING_TYPE nodes. */
17048 /* Unification fails if we hit an error node. */
17052 /* An unresolved overload is a nondeduced context. */
17057 /* We must be looking at an expression. This can happen with
17058 something like:
17060 template <int I>
17061 void foo(S<I>, S<I + 2>);
17063 This is a "nondeduced context":
17065 [deduct.type]
17067 The nondeduced contexts are:
17069 --A type that is a template-id in which one or more of
17070 the template-arguments is an expression that references
17071 a template-parameter.
17073 In these cases, we assume deduction succeeded, but don't
17074 actually infer any unifications. */
17079 else
17081 }
17082 }
17083 #undef RECUR_AND_CHECK_FAILURE
17084 \f
17085 /* Note that DECL can be defined in this translation unit, if
17086 required. */
17088 static void
17090 {
17091 tree clone;
17095 }
17097 /* Called if RESULT is explicitly instantiated, or is a member of an
17098 explicitly instantiated class. */
17100 void
17102 {
17105 /* If this entity has already been written out, it's too late to
17106 make any modifications. */
17111 /* The TREE_PUBLIC flag for function declarations will have been
17112 set correctly by tsubst. */
17115 /* This might have been set by an earlier implicit instantiation. */
17120 else
17121 {
17123 /* Always make artificials weak. */
17126 /* For WIN32 we also want to put explicit instantiations in
17127 linkonce sections. */
17130 }
17132 /* If EXTERN_P, then this function will not be emitted -- unless
17133 followed by an explicit instantiation, at which point its linkage
17134 will be adjusted. If !EXTERN_P, then this function will be
17135 emitted here. In neither circumstance do we want
17136 import_export_decl to adjust the linkage. */
17138 }
17140 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
17141 important template arguments. If any are missing, we check whether
17142 they're important by using error_mark_node for substituting into any
17143 args that were used for partial ordering (the ones between ARGS and END)
17144 and seeing if it bubbles up. */
17146 static bool
17148 {
17153 {
17156 }
17158 {
17162 }
17164 }
17166 /* Given two function templates PAT1 and PAT2, return:
17168 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
17169 -1 if PAT2 is more specialized than PAT1.
17170 0 if neither is more specialized.
17172 LEN indicates the number of parameters we should consider
17173 (defaulted parameters should not be considered).
17175 The 1998 std underspecified function template partial ordering, and
17176 DR214 addresses the issue. We take pairs of arguments, one from
17177 each of the templates, and deduce them against each other. One of
17178 the templates will be more specialized if all the *other*
17179 template's arguments deduce against its arguments and at least one
17180 of its arguments *does* *not* deduce against the other template's
17181 corresponding argument. Deduction is done as for class templates.
17182 The arguments used in deduction have reference and top level cv
17183 qualifiers removed. Iff both arguments were originally reference
17184 types *and* deduction succeeds in both directions, the template
17185 with the more cv-qualified argument wins for that pairing (if
17186 neither is more cv-qualified, they both are equal). Unlike regular
17187 deduction, after all the arguments have been deduced in this way,
17188 we do *not* verify the deduced template argument values can be
17189 substituted into non-deduced contexts.
17191 The logic can be a bit confusing here, because we look at deduce1 and
17192 targs1 to see if pat2 is at least as specialized, and vice versa; if we
17193 can find template arguments for pat1 to make arg1 look like arg2, that
17194 means that arg2 is at least as specialized as arg1. */
17196 int
17198 {
17211 /* Remove the this parameter from non-static member functions. If
17212 one is a non-static member function and the other is not a static
17213 member function, remove the first parameter from that function
17214 also. This situation occurs for operator functions where we
17215 locate both a member function (with this pointer) and non-member
17216 operator (with explicit first operand). */
17218 {
17223 }
17225 {
17228 {
17229 len--;
17231 }
17232 }
17234 /* If only one is a conversion operator, they are unordered. */
17238 /* Consider the return type for a conversion function */
17240 {
17243 len++;
17244 }
17246 processing_template_decl++;
17252 /* Stop when an ellipsis is seen. */
17254 {
17263 {
17264 /* When both arguments are pack expansions, we need only
17265 unify the patterns themselves. */
17269 /* This is the last comparison we need to do. */
17271 }
17274 {
17277 }
17280 {
17283 }
17289 {
17295 /* Setup the parameter vector, which contains only ARG1. */
17298 /* Setup the argument vector, which contains the remaining
17299 arguments. */
17308 /* We cannot deduce in the other direction, because ARG1 is
17309 a pack expansion but ARG2 is not. */
17311 }
17313 {
17319 /* Setup the parameter vector, which contains only ARG1. */
17322 /* Setup the argument vector, which contains the remaining
17323 arguments. */
17332 /* We cannot deduce in the other direction, because ARG2 is
17333 a pack expansion but ARG1 is not.*/
17335 }
17337 else
17338 {
17339 /* The normal case, where neither argument is a pack
17340 expansion. */
17347 }
17349 /* If we couldn't deduce arguments for tparms1 to make arg1 match
17350 arg2, then arg2 is not as specialized as arg1. */
17356 /* "If, for a given type, deduction succeeds in both directions
17357 (i.e., the types are identical after the transformations above)
17358 and if the type from the argument template is more cv-qualified
17359 than the type from the parameter template (as described above)
17360 that type is considered to be more specialized than the other. If
17361 neither type is more cv-qualified than the other then neither type
17362 is more specialized than the other." */
17366 {
17371 }
17374 /* We've failed to deduce something in either direction.
17375 These must be unordered. */
17380 /* We have already processed all of the arguments in our
17381 handing of the pack expansion type. */
17386 }
17388 /* "In most cases, all template parameters must have values in order for
17389 deduction to succeed, but for partial ordering purposes a template
17390 parameter may remain without a value provided it is not used in the
17391 types being used for partial ordering."
17393 Thus, if we are missing any of the targs1 we need to substitute into
17394 origs1, then pat2 is not as specialized as pat1. This can happen when
17395 there is a nondeduced context. */
17401 processing_template_decl--;
17403 /* All things being equal, if the next argument is a pack expansion
17404 for one function but not for the other, prefer the
17405 non-variadic function. FIXME this is bogus; see c++/41958. */
17409 {
17412 }
17418 else
17420 }
17422 /* Determine which of two partial specializations of MAIN_TMPL is more
17423 specialized.
17425 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
17426 to the first partial specialization. The TREE_VALUE is the
17427 innermost set of template parameters for the partial
17428 specialization. PAT2 is similar, but for the second template.
17430 Return 1 if the first partial specialization is more specialized;
17431 -1 if the second is more specialized; 0 if neither is more
17432 specialized.
17434 See [temp.class.order] for information about determining which of
17435 two templates is more specialized. */
17437 static int
17439 {
17440 tree targs;
17448 /* Just like what happens for functions, if we are ordering between
17449 different class template specializations, we may encounter dependent
17450 types in the arguments, and we need our dependency check functions
17451 to behave correctly. */
17457 {
17460 }
17466 {
17469 }
17472 /* In the case of a tie where at least one of the class templates
17473 has a parameter pack at the end, the template with the most
17474 non-packed parameters wins. */
17476 && any_deductions
17479 {
17485 /* We don't count the pack expansion at the end. */
17495 }
17498 }
17500 /* Return the template arguments that will produce the function signature
17501 DECL from the function template FN, with the explicit template
17502 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
17503 also match. Return NULL_TREE if no satisfactory arguments could be
17504 found. */
17506 static tree
17508 {
17512 tree decl_arg_types;
17515 tree arg;
17519 /* Never do unification on the 'this' parameter. */
17539 }
17541 /* Return the innermost template arguments that, when applied to a partial
17542 specialization of MAIN_TMPL whose innermost template parameters are
17543 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
17544 ARGS.
17546 For example, suppose we have:
17548 template <class T, class U> struct S {};
17549 template <class T> struct S<T*, int> {};
17551 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
17552 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
17553 int}. The resulting vector will be {double}, indicating that `T'
17554 is bound to `double'. */
17556 static tree
17558 {
17560 tree deduced_args;
17561 tree innermost_deduced_args;
17565 {
17569 innermost_deduced_args);
17570 }
17571 else
17584 /* Verify that nondeduced template arguments agree with the type
17585 obtained from argument deduction.
17587 For example:
17589 struct A { typedef int X; };
17590 template <class T, class U> struct C {};
17591 template <class T> struct C<T, typename T::X> {};
17593 Then with the instantiation `C<A, int>', we can deduce that
17594 `T' is `A' but unify () does not check whether `typename T::X'
17595 is `int'. */
17601 /* We only need to check the innermost arguments; the other
17602 arguments will always agree. */
17607 /* Now that we have bindings for all of the template arguments,
17608 ensure that the arguments deduced for the template template
17609 parameters have compatible template parameter lists. See the use
17610 of template_template_parm_bindings_ok_p in fn_type_unification
17611 for more information. */
17616 }
17618 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
17619 Return the TREE_LIST node with the most specialized template, if
17620 any. If there is no most specialized template, the error_mark_node
17621 is returned.
17623 Note that this function does not look at, or modify, the
17624 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
17625 returned is one of the elements of INSTANTIATIONS, callers may
17626 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
17627 and retrieve it from the value returned. */
17629 tree
17631 {
17638 {
17644 fate--;
17649 fate++;
17654 {
17655 /* Equally specialized, move to next function. If there
17656 is no next function, nothing's most specialized. */
17661 }
17662 }
17665 /* Now verify that champ is better than everything earlier in the
17666 instantiation list. */
17674 {
17677 }
17679 processing_template_decl--;
17685 }
17687 /* If DECL is a specialization of some template, return the most
17688 general such template. Otherwise, returns NULL_TREE.
17690 For example, given:
17692 template <class T> struct S { template <class U> void f(U); };
17694 if TMPL is `template <class U> void S<int>::f(U)' this will return
17695 the full template. This function will not trace past partial
17696 specializations, however. For example, given in addition:
17698 template <class T> struct S<T*> { template <class U> void f(U); };
17700 if TMPL is `template <class U> void S<int*>::f(U)' this will return
17701 `template <class T> template <class U> S<T*>::f(U)'. */
17703 tree
17705 {
17706 /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is
17707 an immediate specialization. */
17709 {
17713 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a
17714 template friend. */
17719 }
17721 /* Look for more and more general templates. */
17723 {
17724 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
17725 (See cp-tree.h for details.) */
17733 /* Stop if we run into an explicitly specialized class template. */
17740 }
17743 }
17745 /* Return the most specialized of the class template partial
17746 specializations of TMPL which can produce TYPE, a specialization of
17747 TMPL. The value returned is actually a TREE_LIST; the TREE_TYPE is
17748 a _TYPE node corresponding to the partial specialization, while the
17749 TREE_PURPOSE is the set of template arguments that must be
17750 substituted into the TREE_TYPE in order to generate TYPE.
17752 If the choice of partial specialization is ambiguous, a diagnostic
17753 is issued, and the error_mark_node is returned. If there are no
17754 partial specializations of TMPL matching TYPE, then NULL_TREE is
17755 returned. */
17757 static tree
17759 {
17761 tree t;
17762 tree champ;
17765 tree args;
17771 /* For determining which partial specialization to use, only the
17772 innermost args are interesting. */
17774 {
17777 }
17780 {
17781 tree partial_spec_args;
17782 tree spec_args;
17790 {
17793 /* Discard the outer levels of args, and then substitute in the
17794 template args from the enclosing class. */
17796 partial_spec_args = tsubst_template_args
17799 /* PARMS already refers to just the innermost parms, but the
17800 template parms in partial_spec_args had their levels lowered
17801 by tsubst, so we need to do the same for the parm list. We
17802 can't just tsubst the TREE_VEC itself, as tsubst wants to
17803 treat a TREE_VEC as an argument vector. */
17809 }
17811 partial_spec_args =
17814 partial_spec_args),
17825 partial_spec_args,
17826 args);
17828 {
17833 }
17834 }
17844 {
17847 ;
17848 else
17849 {
17851 {
17854 {
17857 }
17858 }
17860 }
17861 }
17865 {
17868 {
17871 }
17872 }
17875 {
17883 {
17886 }
17889 }
17892 }
17894 /* Explicitly instantiate DECL. */
17896 void
17898 {
17903 /* An error occurred, for which grokdeclarator has already issued
17904 an appropriate message. */
17907 {
17910 }
17912 {
17913 /* There is an asymmetry here in the way VAR_DECLs and
17914 FUNCTION_DECLs are handled by grokdeclarator. In the case of
17915 the latter, the DECL we get back will be marked as a
17916 template instantiation, and the appropriate
17917 DECL_TEMPLATE_INFO will be set up. This does not happen for
17918 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
17919 should handle VAR_DECLs as it currently handles
17920 FUNCTION_DECLs. */
17922 {
17925 }
17928 {
17931 }
17933 {
17938 }
17939 }
17941 {
17944 }
17945 else
17948 /* Check for various error cases. Note that if the explicit
17949 instantiation is valid the RESULT will currently be marked as an
17950 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
17951 until we get here. */
17954 {
17955 /* DR 259 [temp.spec].
17957 Both an explicit instantiation and a declaration of an explicit
17958 specialization shall not appear in a program unless the explicit
17959 instantiation follows a declaration of the explicit specialization.
17961 For a given set of template parameters, if an explicit
17962 instantiation of a template appears after a declaration of an
17963 explicit specialization for that template, the explicit
17964 instantiation has no effect. */
17966 }
17968 {
17969 /* [temp.spec]
17971 No program shall explicitly instantiate any template more
17972 than once.
17974 We check DECL_NOT_REALLY_EXTERN so as not to complain when
17975 the first instantiation was `extern' and the second is not,
17976 and EXTERN_P for the opposite case. */
17979 /* If an "extern" explicit instantiation follows an ordinary
17980 explicit instantiation, the template is instantiated. */
17983 }
17985 {
17988 }
17990 {
17993 }
17996 ;
17998 {
18001 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
18004 }
18005 else
18013 }
18015 static void
18017 {
18023 {
18026 }
18027 }
18029 /* Called from do_type_instantiation through binding_table_foreach to
18030 do recursive instantiation for the type bound in ENTRY. */
18031 static void
18033 {
18039 }
18041 /* Called from do_type_instantiation to instantiate a member
18042 (a member function or a static member variable) of an
18043 explicitly instantiated class template. */
18044 static void
18046 {
18051 }
18053 /* Perform an explicit instantiation of template class T. STORAGE, if
18054 non-null, is the RID for extern, inline or static. COMPLAIN is
18055 nonzero if this is called from the parser, zero if called recursively,
18056 since the standard is unclear (as detailed below). */
18058 void
18060 {
18070 {
18071 tree tmpl =
18075 else
18078 }
18083 {
18086 t);
18088 }
18091 {
18093 {
18095 {
18098 "ISO C++ 1998 forbids the use of %<extern%> on "
18100 }
18101 else
18103 "ISO C++ forbids the use of %qE"
18105 }
18113 else
18114 {
18116 storage);
18118 }
18119 }
18122 {
18123 /* DR 259 [temp.spec].
18125 Both an explicit instantiation and a declaration of an explicit
18126 specialization shall not appear in a program unless the explicit
18127 instantiation follows a declaration of the explicit specialization.
18129 For a given set of template parameters, if an explicit
18130 instantiation of a template appears after a declaration of an
18131 explicit specialization for that template, the explicit
18132 instantiation has no effect. */
18134 }
18136 {
18137 /* [temp.spec]
18139 No program shall explicitly instantiate any template more
18140 than once.
18142 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
18143 instantiation was `extern'. If EXTERN_P then the second is.
18144 These cases are OK. */
18151 /* If we've already instantiated the template, just return now. */
18154 }
18162 {
18163 tree tmp;
18165 /* In contrast to implicit instantiation, where only the
18166 declarations, and not the definitions, of members are
18167 instantiated, we have here:
18169 [temp.explicit]
18171 The explicit instantiation of a class template specialization
18172 implies the instantiation of all of its members not
18173 previously explicitly specialized in the translation unit
18174 containing the explicit instantiation.
18176 Of course, we can't instantiate member template classes, since
18177 we don't have any arguments for them. Note that the standard
18178 is unclear on whether the instantiation of the members are
18179 *explicit* instantiations or not. However, the most natural
18180 interpretation is that it should be an explicit instantiation. */
18195 }
18196 }
18198 /* Given a function DECL, which is a specialization of TMPL, modify
18199 DECL to be a re-instantiation of TMPL with the same template
18200 arguments. TMPL should be the template into which tsubst'ing
18201 should occur for DECL, not the most general template.
18203 One reason for doing this is a scenario like this:
18205 template <class T>
18206 void f(const T&, int i);
18208 void g() { f(3, 7); }
18210 template <class T>
18211 void f(const T& t, const int i) { }
18213 Note that when the template is first instantiated, with
18214 instantiate_template, the resulting DECL will have no name for the
18215 first parameter, and the wrong type for the second. So, when we go
18216 to instantiate the DECL, we regenerate it. */
18218 static void
18220 {
18221 /* The arguments used to instantiate DECL, from the most general
18222 template. */
18223 tree args;
18224 tree code_pattern;
18229 /* Make sure that we can see identifiers, and compute access
18230 correctly. */
18234 {
18235 tree decl_parm;
18236 tree pattern_parm;
18237 tree specs;
18251 specs);
18253 /* Merge parameter declarations. */
18256 pattern_parm
18260 {
18261 tree parm_type;
18262 tree attributes;
18267 NULL_TREE);
18273 {
18276 }
18279 }
18280 /* Merge any parameters that match with the function parameter
18281 pack. */
18283 {
18285 tree expanded_types;
18286 /* Expand the TYPE_PACK_EXPANSION that provides the types for
18287 the parameters in this function parameter pack. */
18292 {
18293 tree parm_type;
18294 tree attributes;
18297 /* Rename the parameter to include the index. */
18306 {
18309 }
18311 }
18312 }
18313 /* Merge additional specifiers from the CODE_PATTERN. */
18317 }
18319 {
18327 }
18328 else
18332 }
18334 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
18335 substituted to get DECL. */
18337 tree
18339 {
18342 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
18343 for the instantiation. This is not always the most general
18344 template. Consider, for example:
18346 template <class T>
18347 struct S { template <class U> void f();
18348 template <> void f<int>(); };
18350 and an instantiation of S<double>::f<int>. We want TD to be the
18351 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
18353 more general template. */
18355 /* We must also deal with friend templates. Given:
18357 template <class T> struct S {
18358 template <class U> friend void f() {};
18359 };
18361 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
18362 so far as the language is concerned, but that's still
18363 where we get the pattern for the instantiation from. On
18364 other hand, if the definition comes outside the class, say:
18366 template <class T> struct S {
18367 template <class U> friend void f();
18368 };
18369 template <class U> friend void f() {}
18371 we don't need to look any further. That's what the check for
18372 DECL_INITIAL is for. */
18376 {
18377 /* The present template, TD, should not be a definition. If it
18378 were a definition, we should be using it! Note that we
18379 cannot restructure the loop to just keep going until we find
18380 a template with a definition, since that might go too far if
18381 a specialization was declared, but not defined. */
18385 /* Fetch the more general template. */
18387 }
18390 }
18392 /* Returns true if we need to instantiate this template instance even if we
18393 know we aren't going to emit it.. */
18395 bool
18397 {
18398 /* We always instantiate inline functions so that we can inline them. An
18399 explicit instantiation declaration prohibits implicit instantiation of
18400 non-inline functions. With high levels of optimization, we would
18401 normally inline non-inline functions -- but we're not allowed to do
18402 that for "extern template" functions. Therefore, we check
18403 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
18407 /* And we need to instantiate static data members so that
18408 their initializers are available in integral constant
18409 expressions. */
18412 }
18414 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
18415 instantiate it now, modifying TREE_TYPE (fn). */
18417 void
18419 {
18433 {
18435 {
18450 }
18451 else
18453 }
18454 else
18455 {
18456 /* This is an implicitly declared function, so NOEX is a list of
18457 other functions to evaluate and merge. */
18458 tree elt;
18461 {
18463 tree subspec;
18467 }
18468 }
18473 {
18476 else
18478 }
18479 }
18481 /* Produce the definition of D, a _DECL generated from a template. If
18482 DEFER_OK is nonzero, then we don't have to actually do the
18483 instantiation now; we just have to do it sometime. Normally it is
18484 an error if this is an explicit instantiation but D is undefined.
18485 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
18486 explicitly instantiated class template. */
18488 tree
18491 {
18493 tree gen_args;
18494 tree args;
18495 tree td;
18496 tree code_pattern;
18497 tree spec;
18498 tree gen_tmpl;
18502 tree fn_context;
18505 /* This function should only be used to instantiate templates for
18506 functions and static member variables. */
18510 /* Variables are never deferred; if instantiation is required, they
18511 are instantiated right away. That allows for better code in the
18512 case that an expression refers to the value of the variable --
18513 if the variable has a constant value the referring expression can
18514 take advantage of that fact. */
18519 /* Don't instantiate cloned functions. Instead, instantiate the
18520 functions they cloned. */
18528 /* D has already been instantiated or explicitly specialized, so
18529 there's nothing for us to do here.
18531 It might seem reasonable to check whether or not D is an explicit
18532 instantiation, and, if so, stop here. But when an explicit
18533 instantiation is deferred until the end of the compilation,
18534 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
18535 the instantiation. */
18538 /* Check to see whether we know that this template will be
18539 instantiated in some other file, as with "extern template"
18540 extension. */
18543 /* In general, we do not instantiate such templates. */
18551 /* We should already have the extra args. */
18554 /* And what's in the hash table should match D. */
18558 /* This needs to happen before any tsubsting. */
18564 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
18565 for the instantiation. */
18569 /* We should never be trying to instantiate a member of a class
18570 template or partial specialization. */
18575 /* In the case of a friend template whose definition is provided
18576 outside the class, we may have too many arguments. Drop the
18577 ones we don't need. The same is true for specializations. */
18578 args = get_innermost_template_args
18580 else
18586 else
18589 /* We may be in the middle of deferred access check. Disable it now. */
18592 /* Unless an explicit instantiation directive has already determined
18593 the linkage of D, remember that a definition is available for
18594 this entity. */
18604 /* If D is a member of an explicitly instantiated class template,
18605 and no definition is available, treat it like an implicit
18606 instantiation. */
18609 {
18610 /* Leave linkage flags alone on instantiations with anonymous
18611 visibility. */
18613 {
18616 }
18618 }
18623 /* Defer all other templates, unless we have been explicitly
18624 forbidden from doing so. */
18626 template. */
18627 ! pattern_defined
18628 /* If it's OK to postpone instantiation, do so. */
18629 || defer_ok
18630 /* If this is a static data member that will be defined
18631 elsewhere, we don't want to instantiate the entire data
18632 member, but we do want to instantiate the initializer so that
18633 we can substitute that elsewhere. */
18635 {
18636 /* The definition of the static data member is now required so
18637 we must substitute the initializer. */
18641 {
18642 tree ns;
18643 tree init;
18650 args,
18653 /* Make sure the initializer is still constant, in case of
18654 circular dependency (template/instantiate6.C). */
18655 const_init
18659 LOOKUP_ONLYCONVERTING);
18662 }
18664 /* We restore the source position here because it's used by
18665 add_pending_template. */
18671 /* [temp.explicit]
18673 The definition of a non-exported function template, a
18674 non-exported member function template, or a non-exported
18675 member function or static data member of a class template
18676 shall be present in every translation unit in which it is
18677 explicitly instantiated. */
18681 /* If we're in unevaluated context, we just wanted to get the
18682 constant value; this isn't an odr use, so don't queue
18683 a full instantiation. */
18686 /* ??? Historically, we have instantiated inline functions, even
18687 when marked as "extern template". */
18691 }
18692 /* Tell the repository that D is available in this translation unit
18693 -- and see if it is supposed to be instantiated here. */
18695 {
18696 /* In a PCH file, despite the fact that the repository hasn't
18697 requested instantiation in the PCH it is still possible that
18698 an instantiation will be required in a file that includes the
18699 PCH. */
18702 /* Instantiate inline functions so that the inliner can do its
18703 job, even though we'll not be emitting a copy of this
18704 function. */
18707 }
18716 /* Mark D as instantiated so that recursive calls to
18717 instantiate_decl do not try to instantiate it again. */
18720 /* Regenerate the declaration in case the template has been modified
18721 by a subsequent redeclaration. */
18724 /* We already set the file and line above. Reset them now in case
18725 they changed as a result of calling regenerate_decl_from_template. */
18729 {
18730 tree init;
18733 /* Clear out DECL_RTL; whatever was there before may not be right
18734 since we've reset the type of the declaration. */
18738 /* The initializer is placed in DECL_INITIAL by
18739 regenerate_decl_from_template so we don't need to
18740 push/pop_access_scope again here. Pull it out so that
18741 cp_finish_decl can process it. */
18746 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
18747 initializer. That function will defer actual emission until
18748 we have a chance to determine linkage. */
18751 /* Enter the scope of D so that access-checking works correctly. */
18756 }
18760 {
18762 tree subst_decl;
18763 tree tmpl_parm;
18764 tree spec_parm;
18766 /* Save away the current list, in case we are instantiating one
18767 template from within the body of another. */
18770 /* Set up the list of local specializations. */
18773 /* Set up context. */
18776 /* Some typedefs referenced from within the template code need to be
18777 access checked at template instantiation time, i.e now. These
18778 types were added to the template at parsing time. Let's get those
18779 and perform the access checks then. */
18781 gen_args);
18783 /* Create substitution entries for the parameters. */
18788 {
18792 }
18794 {
18796 {
18799 }
18800 else
18801 {
18802 /* Register the (value) argument pack as a specialization of
18803 TMPL_PARM, then move on. */
18806 }
18807 }
18810 /* Substitute into the body of the function. */
18815 /* Set the current input_location to the end of the function
18816 so that finish_function knows where we are. */
18819 /* We don't need the local specializations any more. */
18823 /* Finish the function. */
18826 }
18828 /* We're not deferring instantiation any more. */
18836 out:
18844 }
18846 /* Run through the list of templates that we wish we could
18847 instantiate, and instantiate any we can. RETRIES is the
18848 number of times we retry pending template instantiation. */
18850 void
18852 {
18856 /* Instantiating templates may trigger vtable generation. This in turn
18857 may require further template instantiations. We place a limit here
18858 to avoid infinite loop. */
18860 {
18864 " instantiating %q+D, possibly from virtual table generation"
18868 /* Pretend that we defined it. */
18871 }
18873 do
18874 {
18879 {
18884 {
18885 tree fn;
18888 {
18892 fn;
18900 }
18903 }
18904 else
18905 {
18908 {
18909 instantiation
18915 }
18919 }
18922 /* If INSTANTIATION has been instantiated, then we don't
18923 need to consider it again in the future. */
18925 else
18926 {
18929 }
18932 }
18934 }
18938 }
18940 /* Substitute ARGVEC into T, which is a list of initializers for
18941 either base class or a non-static data member. The TREE_PURPOSEs
18942 are DECLs, and the TREE_VALUEs are the initializer values. Used by
18943 instantiate_decl. */
18945 static tree
18947 {
18951 {
18952 tree decl;
18953 tree init;
18959 {
18960 tree expr;
18961 tree arg;
18963 /* Expand the base class expansion type into separate base
18964 classes. */
18966 tf_warning_or_error,
18967 NULL_TREE);
18971 /* We'll be building separate TREE_LISTs of arguments for
18972 each base. */
18978 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
18979 expand each argument in the TREE_VALUE of t. */
18986 /* VOID_TYPE_NODE is used to indicate
18987 value-initialization. */
18988 {
18991 }
18992 else
18993 {
18994 /* Substitute parameter packs into each argument in the
18995 TREE_LIST. */
18998 {
18999 tree expanded_exprs;
19001 /* Expand the argument. */
19003 expanded_exprs
19005 tf_warning_or_error,
19006 NULL_TREE);
19010 /* Prepend each of the expanded expressions to the
19011 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
19013 {
19018 }
19019 }
19022 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
19023 since we built them backwards. */
19025 {
19028 }
19029 }
19030 }
19033 {
19035 {
19039 }
19040 else
19041 {
19042 tree tmp;
19057 /* If we had an initializer but it instantiated to nothing,
19058 value-initialize the object. This will only occur when
19059 the initializer was a pack expansion where the parameter
19060 packs used in that expansion were of length zero. */
19063 }
19066 {
19070 }
19071 }
19072 }
19074 }
19076 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
19078 static void
19080 {
19085 else
19087 }
19089 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
19090 is the instantiation (which should have been created with
19091 start_enum) and ARGS are the template arguments to use. */
19093 static void
19095 {
19096 tree e;
19102 {
19103 tree value;
19104 tree decl;
19107 /* Note that in a template enum, the TREE_VALUE is the
19108 CONST_DECL, not the corresponding INTEGER_CST. */
19113 /* Give this enumeration constant the correct access. */
19116 /* Actually build the enumerator itself. */
19117 build_enumerator
19119 }
19129 }
19131 /* DECL is a FUNCTION_DECL that is a template specialization. Return
19132 its type -- but without substituting the innermost set of template
19133 arguments. So, innermost set of template parameters will appear in
19134 the type. */
19136 tree
19138 {
19139 tree fn_type;
19140 tree tmpl;
19141 tree targs;
19142 tree tparms;
19150 /* There should be as many levels of arguments as there are levels
19151 of parameters. */
19157 /* No substitution is necessary. */
19158 ;
19159 else
19160 {
19162 tree partial_args;
19164 /* Replace the innermost level of the TARGS with NULL_TREEs to
19165 let tsubst know not to substitute for those parameters. */
19174 /* Make sure that we can see identifiers, and compute access
19175 correctly. */
19179 /* Now, do the (partial) substitution to figure out the
19180 appropriate function type. */
19184 /* Substitute into the template parameters to obtain the real
19185 innermost set of parameters. This step is important if the
19186 innermost set of template parameters contains value
19187 parameters whose types depend on outer template parameters. */
19192 }
19195 }
19197 /* Return truthvalue if we're processing a template different from
19198 the last one involved in diagnostics. */
19199 int
19201 {
19203 }
19205 /* Remember current template involved in diagnostics. */
19206 void
19208 {
19210 }
19214 {
19216 }
19218 /* [temp.param] Check that template non-type parm TYPE is of an allowable
19219 type. Return zero for ok, nonzero for disallowed. Issue error and
19220 warning messages under control of COMPLAIN. */
19222 static int
19224 {
19241 {
19244 else
19246 type);
19247 }
19249 }
19251 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
19252 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
19254 static bool
19256 {
19257 tree scope;
19259 /* [temp.dep.type]
19261 A type is dependent if it is:
19263 -- a template parameter. Template template parameters are types
19264 for us (since TYPE_P holds true for them) so we handle
19265 them here. */
19269 /* -- a qualified-id with a nested-name-specifier which contains a
19270 class-name that names a dependent type or whose unqualified-id
19271 names a dependent type. */
19274 /* -- a cv-qualified type where the cv-unqualified type is
19275 dependent. */
19277 /* -- a compound type constructed from any dependent type. */
19287 {
19288 tree arg_type;
19293 arg_type;
19298 }
19299 /* -- an array type constructed from any dependent type or whose
19300 size is specified by a constant expression that is
19301 value-dependent.
19303 We checked for type- and value-dependence of the bounds in
19304 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
19306 {
19311 }
19313 /* -- a template-id in which either the template name is a template
19314 parameter ... */
19317 /* ... or any of the template arguments is a dependent type or
19318 an expression that is type-dependent or value-dependent. */
19320 && (any_dependent_template_arguments_p
19324 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
19325 dependent; if the argument of the `typeof' expression is not
19326 type-dependent, then it should already been have resolved. */
19332 /* A template argument pack is dependent if any of its packed
19333 arguments are. */
19335 {
19341 }
19343 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
19344 be template parameters. */
19348 /* The standard does not specifically mention types that are local
19349 to template functions or local classes, but they should be
19350 considered dependent too. For example:
19352 template <int I> void f() {
19353 enum E { a = I };
19354 S<sizeof (E)> s;
19355 }
19357 The size of `E' cannot be known until the value of `I' has been
19358 determined. Therefore, `E' must be considered dependent. */
19362 /* Don't use type_dependent_expression_p here, as it can lead
19363 to infinite recursion trying to determine whether a lambda
19364 nested in a lambda is dependent (c++/47687). */
19368 && (any_dependent_template_arguments_p
19372 /* Other types are non-dependent. */
19374 }
19376 /* Returns TRUE if TYPE is dependent, in the sense of
19377 [temp.dep.type]. Note that a NULL type is considered dependent. */
19379 bool
19381 {
19382 /* If there are no template parameters in scope, then there can't be
19383 any dependent types. */
19385 {
19386 /* If we are not processing a template, then nobody should be
19387 providing us with a dependent type. */
19391 }
19393 /* If the type is NULL, we have not computed a type for the entity
19394 in question; in that case, the type is dependent. */
19398 /* Erroneous types can be considered non-dependent. */
19402 /* If we have not already computed the appropriate value for TYPE,
19403 do so now. */
19405 {
19408 }
19411 }
19413 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
19414 lookup. In other words, a dependent type that is not the current
19415 instantiation. */
19417 bool
19419 {
19422 }
19424 /* T is a SCOPE_REF; return whether we need to consider it
19425 instantiation-dependent so that we can check access at instantiation
19426 time even though we know which member it resolves to. */
19428 static bool
19430 {
19436 else
19438 }
19440 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
19441 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
19442 expression. */
19444 /* Note that this predicate is not appropriate for general expressions;
19445 only constant expressions (that satisfy potential_constant_expression)
19446 can be tested for value dependence. */
19448 bool
19450 {
19454 /* A name declared with a dependent type. */
19459 {
19461 /* A name that has not been looked up -- must be dependent. */
19465 /* A non-type template parm. */
19469 /* A non-type template parm. */
19475 /* A constant with literal type and is initialized
19476 with an expression that is value-dependent.
19478 Note that a non-dependent parenthesized initializer will have
19479 already been replaced with its constant value, so if we see
19480 a TREE_LIST it must be dependent. */
19493 /* These expressions are value-dependent if the type to which
19494 the cast occurs is dependent or the expression being casted
19495 is value-dependent. */
19496 {
19502 /* A functional cast has a list of operands. */
19505 {
19506 /* If there are no operands, it must be an expression such
19507 as "int()". This should not happen for aggregate types
19508 because it would form non-constant expressions. */
19513 }
19519 }
19524 /* FALLTHRU */
19527 /* A `sizeof' expression is value-dependent if the operand is
19528 type-dependent or is a pack expansion. */
19537 /* An 'encode' expression is value-dependent if the operand is
19538 type-dependent. */
19547 /* All instantiation-dependent expressions should also be considered
19548 value-dependent. */
19556 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
19557 is value-dependent. */
19558 {
19567 }
19570 {
19574 }
19585 {
19589 }
19592 {
19599 {
19601 /* In a call to a constexpr member function, look through the
19602 implicit ADDR_EXPR on the object argument so that it doesn't
19603 cause the call to be considered value-dependent. We also
19604 look through it in potential_constant_expression. */
19611 }
19613 }
19616 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
19617 type-dependent. */
19621 {
19623 tree val;
19628 }
19631 /* Treat a GNU statement expression as dependent to avoid crashing
19632 under fold_non_dependent_expr; it can't be constant. */
19636 /* A constant expression is value-dependent if any subexpression is
19637 value-dependent. */
19639 {
19646 {
19650 {
19653 /* In some cases, some of the operands may be missing.l
19654 (For example, in the case of PREDECREMENT_EXPR, the
19655 amount to increment by may be missing.) That doesn't
19656 make the expression dependent. */
19659 }
19660 }
19664 }
19666 }
19668 /* The expression is not value-dependent. */
19670 }
19672 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
19673 [temp.dep.expr]. Note that an expression with no type is
19674 considered dependent. Other parts of the compiler arrange for an
19675 expression with type-dependent subexpressions to have no type, so
19676 this function doesn't have to be fully recursive. */
19678 bool
19680 {
19687 /* An unresolved name is always dependent. */
19692 /* Some expression forms are never type-dependent. */
19705 /* The types of these expressions depends only on the type to which
19706 the cast occurs. */
19715 /* The types of these expressions depends only on the type created
19716 by the expression. */
19719 {
19720 /* For NEW_EXPR tree nodes created inside a template, either
19721 the object type itself or a TREE_LIST may appear as the
19722 operand 1. */
19725 /* This is an array type. We need to check array dimensions
19726 as well. */
19728 || value_dependent_expression_p
19730 else
19732 }
19735 {
19739 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
19740 contains an identifier associated by name lookup with one or more
19741 declarations declared with a dependent type, or...a
19742 nested-name-specifier or qualified-id that names a member of an
19743 unknown specialization. */
19746 }
19751 && (any_dependent_template_arguments_p
19763 {
19764 tree elt;
19768 {
19771 }
19773 }
19775 /* A static data member of the current instantiation with incomplete
19776 array type is type-dependent, as the definition and specializations
19777 can have different bounds. */
19785 {
19790 {
19796 }
19797 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
19805 {
19810 }
19815 {
19819 }
19821 }
19826 }
19828 /* walk_tree callback function for instantiation_dependent_expression_p,
19829 below. Returns non-zero if a dependent subexpression is found. */
19831 static tree
19834 {
19836 {
19837 /* We don't have to worry about decltype currently because decltype
19838 of an instantiation-dependent expr is a dependent type. This
19839 might change depending on the resolution of DR 1172. */
19842 }
19845 {
19846 /* Don't treat an argument list as dependent just because it has no
19847 TREE_TYPE. */
19855 /* Handle expressions with type operands. */
19861 {
19866 {
19871 else
19872 {
19875 }
19876 }
19878 }
19882 /* In a template, finish_class_member_access_expr creates a
19883 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
19884 type-dependent, so that we can check access control at
19885 instantiation time (PR 42277). See also Core issue 1273. */
19892 else
19897 }
19901 else
19903 }
19905 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
19906 sense defined by the ABI:
19908 "An expression is instantiation-dependent if it is type-dependent
19909 or value-dependent, or it has a subexpression that is type-dependent
19910 or value-dependent." */
19912 bool
19914 {
19915 tree result;
19926 }
19928 /* Like type_dependent_expression_p, but it also works while not processing
19929 a template definition, i.e. during substitution or mangling. */
19931 bool
19933 {
19939 }
19941 /* Returns TRUE if ARGS contains a type-dependent expression. */
19943 bool
19945 {
19947 tree arg;
19950 {
19953 }
19955 }
19957 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
19958 expressions) contains any type-dependent expressions. */
19960 bool
19962 {
19968 }
19970 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
19971 expressions) contains any value-dependent expressions. */
19973 bool
19975 {
19981 }
19983 /* Returns TRUE if the ARG (a template argument) is dependent. */
19985 bool
19987 {
19991 /* Assume a template argument that was wrongly written by the user
19992 is dependent. This is consistent with what
19993 any_dependent_template_arguments_p [that calls this function]
19994 does. */
20005 {
20009 {
20012 }
20015 }
20018 else
20021 }
20023 /* Returns true if ARGS (a collection of template arguments) contains
20024 any types that require structural equality testing. */
20026 bool
20028 {
20038 {
20041 {
20047 {
20048 /* Look inside the argument pack. */
20051 }
20054 {
20068 }
20069 }
20070 }
20073 }
20075 /* Returns true if ARGS (a collection of template arguments) contains
20076 any dependent arguments. */
20078 bool
20080 {
20090 {
20095 }
20098 }
20100 /* Returns TRUE if the template TMPL is dependent. */
20102 bool
20104 {
20106 {
20108 {
20112 }
20114 }
20116 /* Template template parameters are dependent. */
20120 /* So are names that have not been looked up. */
20124 /* So are member templates of dependent classes. */
20128 }
20130 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
20132 bool
20134 {
20137 }
20139 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
20140 is dependent. */
20142 bool
20144 {
20151 {
20172 {
20176 }
20180 {
20184 {
20189 }
20190 }
20191 }
20194 }
20196 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
20197 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
20198 no such TYPE can be found. Note that this function peers inside
20199 uninstantiated templates and therefore should be used only in
20200 extremely limited situations. ONLY_CURRENT_P restricts this
20201 peering to the currently open classes hierarchy (which is required
20202 when comparing types). */
20204 tree
20206 {
20207 tree scope;
20208 tree name;
20209 tree decl;
20211 tree pushed_scope;
20212 tree result;
20217 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
20218 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
20219 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
20220 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
20221 identifier of the TYPENAME_TYPE anymore.
20222 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
20223 TYPENAME_TYPE instead, we avoid messing up with a possible
20224 typedef variant case. */
20227 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
20228 it first before we can figure out what NAME refers to. */
20230 {
20232 /* Given a class template A with a dependent base with nested type C,
20233 typedef typename A::C::C C will land us here, as trying to resolve
20234 the initial A::C leads to the local C typedef, which leads back to
20235 A::C::C. So we break the recursion now. */
20237 else
20239 }
20240 /* If we don't know what SCOPE refers to, then we cannot resolve the
20241 TYPENAME_TYPE. */
20244 /* If the SCOPE is a template type parameter, we have no way of
20245 resolving the name. */
20248 /* If the SCOPE is not the current instantiation, there's no reason
20249 to look inside it. */
20252 /* If this is a typedef, we don't want to look inside (c++/11987). */
20255 /* If SCOPE isn't the template itself, it will not have a valid
20256 TYPE_FIELDS list. */
20258 /* scope is either the template itself or a compatible instantiation
20259 like X<T>, so look up the name in the original template. */
20261 else
20262 /* scope is a partial instantiation, so we can't do the lookup or we
20263 will lose the template arguments. */
20265 /* Enter the SCOPE so that name lookup will be resolved as if we
20266 were in the class definition. In particular, SCOPE will no
20267 longer be considered a dependent type. */
20269 /* Look up the declaration. */
20271 tf_warning_or_error);
20275 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
20276 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
20281 {
20285 }
20288 {
20289 tree tmpl;
20290 tree args;
20291 /* Obtain the template and the arguments. */
20294 /* Instantiate the template. */
20300 }
20302 /* Leave the SCOPE. */
20306 /* If we failed to resolve it, return the original typename. */
20310 /* If lookup found a typename type, resolve that too. */
20312 {
20313 /* Ill-formed programs can cause infinite recursion here, so we
20314 must catch that. */
20318 }
20320 /* Qualify the resulting type. */
20326 }
20328 /* EXPR is an expression which is not type-dependent. Return a proxy
20329 for EXPR that can be used to compute the types of larger
20330 expressions containing EXPR. */
20332 tree
20334 {
20335 tree inner_expr;
20337 #ifdef ENABLE_CHECKING
20338 /* Try to get a constant value for all non-type-dependent expressions in
20339 order to expose bugs in *_dependent_expression_p and constexpr. */
20342 #endif
20344 /* Preserve OVERLOADs; the functions must be available to resolve
20345 types. */
20356 /* There is no need to return a proxy for a variable. */
20359 /* Preserve string constants; conversions from string constants to
20360 "char *" are allowed, even though normally a "const char *"
20361 cannot be used to initialize a "char *". */
20364 /* Preserve arithmetic constants, as an optimization -- there is no
20365 reason to create a new node. */
20368 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
20369 There is at least one place where we want to know that a
20370 particular expression is a throw-expression: when checking a ?:
20371 expression, there are special rules if the second or third
20372 argument is a throw-expression. */
20376 /* Don't wrap an initializer list, we need to be able to look inside. */
20380 /* Don't wrap a dummy object, we need to be able to test for it. */
20399 /* If the type is unknown, it can't really be non-dependent */
20402 /* Otherwise, build a NON_DEPENDENT_EXPR. */
20404 }
20406 /* ARGS is a vector of expressions as arguments to a function call.
20407 Replace the arguments with equivalent non-dependent expressions.
20408 This modifies ARGS in place. */
20410 void
20412 {
20414 tree arg;
20417 {
20421 }
20422 }
20424 /* Returns a type which represents 'auto'. We use a TEMPLATE_TYPE_PARM
20425 with a level one deeper than the actual template parms. */
20427 tree
20429 {
20442 }
20444 /* Given type ARG, return std::initializer_list<ARG>. */
20446 static tree
20448 {
20449 tree std_init_list = namespace_binding
20451 tree argvec;
20453 {
20457 }
20462 }
20464 /* Replace auto in TYPE with std::initializer_list<auto>. */
20466 static tree
20468 {
20475 }
20477 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
20478 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
20480 tree
20482 {
20491 /* Defining a subset of type-dependent expressions that we can deduce
20492 from ahead of time isn't worth the trouble. */
20495 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
20496 with either a new invented type template parameter U or, if the
20497 initializer is a braced-init-list (8.5.4), with
20498 std::initializer_list<U>. */
20514 {
20516 /* Try again at instantiation time. */
20519 /* If type is error_mark_node a diagnostic must have been
20520 emitted by now. Also, having a mention to '<type error>'
20521 in the diagnostic is not really useful to the user. */
20522 {
20526 else
20528 }
20530 }
20532 /* If the list of declarators contains more than one declarator, the type
20533 of each declared variable is determined as described above. If the
20534 type deduced for the template parameter U is not the same in each
20535 deduction, the program is ill-formed. */
20538 {
20544 else
20548 }
20554 }
20556 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
20557 result. */
20559 tree
20561 {
20562 tree argvec;
20569 /* For a late-specified return type in a template type-parameter, we
20570 need to add a dummy argument level for its parmlist. */
20571 argvec = add_to_template_args
20576 }
20578 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto'. */
20580 bool
20582 {
20586 else
20588 }
20590 /* Returns true iff TYPE contains a use of 'auto'. Since auto can only
20591 appear as a type-specifier for the declaration in question, we don't
20592 have to look through the whole type. */
20594 tree
20596 {
20613 }
20615 /* For a given template T, return the vector of typedefs referenced
20616 in T for which access check is needed at T instantiation time.
20617 T is either a FUNCTION_DECL or a RECORD_TYPE.
20618 Those typedefs were added to T by the function
20619 append_type_to_template_for_access_check. */
20623 {
20624 tree ti;
20635 {
20640 }
20643 }
20645 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
20646 tied to T. That list of typedefs will be access checked at
20647 T instantiation time.
20648 T is either a FUNCTION_DECL or a RECORD_TYPE.
20649 TYPE_DECL is a TYPE_DECL node representing a typedef.
20650 SCOPE is the scope through which TYPE_DECL is accessed.
20651 LOCATION is the location of the usage point of TYPE_DECL.
20653 This function is a subroutine of
20654 append_type_to_template_for_access_check. */
20656 static void
20658 tree type_decl,
20659 tree scope,
20660 location_t location)
20661 {
20662 qualified_typedef_usage_t typedef_usage;
20663 tree ti;
20670 && type_decl
20684 }
20686 /* Append TYPE_DECL to the template TEMPL.
20687 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
20688 At TEMPL instanciation time, TYPE_DECL will be checked to see
20689 if it can be accessed through SCOPE.
20690 LOCATION is the location of the usage point of TYPE_DECL.
20692 e.g. consider the following code snippet:
20694 class C
20695 {
20696 typedef int myint;
20697 };
20699 template<class U> struct S
20700 {
20701 C::myint mi; // <-- usage point of the typedef C::myint
20702 };
20704 S<char> s;
20706 At S<char> instantiation time, we need to check the access of C::myint
20707 In other words, we need to check the access of the myint typedef through
20708 the C scope. For that purpose, this function will add the myint typedef
20709 and the scope C through which its being accessed to a list of typedefs
20710 tied to the template S. That list will be walked at template instantiation
20711 time and access check performed on each typedefs it contains.
20712 Note that this particular code snippet should yield an error because
20713 myint is private to C. */
20715 void
20717 tree type_decl,
20718 tree scope,
20719 location_t location)
20720 {
20726 /* Make sure we don't append the type to the template twice. */
20733 }
20735 /* Set up the hash tables for template instantiations. */
20737 void
20739 {
20741 hash_specialization,
20742 eq_specializations,
20743 ggc_free);
20745 hash_specialization,
20746 eq_specializations,
20747 ggc_free);
20748 }
20750 /* Print stats about the template hash tables for -fstats. */
20752 void
20754 {
20763 }