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1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2014 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
50 /* The type of functions taking a tree, and some additional data, and
51 returning an int. */
54 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
55 instantiations have been deferred, either because their definitions
56 were not yet available, or because we were putting off doing the work. */
60 };
75 /* Live only within one (recursive) call to tsubst_expr. We use
76 this to pass the statement expression node from the STMT_EXPR
77 to the EXPR_STMT that is its result. */
80 /* True if we've recursed into fn_type_unification too many times. */
84 {
85 tree tmpl;
86 tree args;
87 tree spec;
88 };
91 {
94 };
100 /* Contains canonical template parameter types. The vector is indexed by
101 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
102 TREE_LIST, whose TREE_VALUEs contain the canonical template
103 parameters of various types and levels. */
106 #define UNIFY_ALLOW_NONE 0
107 #define UNIFY_ALLOW_MORE_CV_QUAL 1
108 #define UNIFY_ALLOW_LESS_CV_QUAL 2
109 #define UNIFY_ALLOW_DERIVED 4
110 #define UNIFY_ALLOW_INTEGER 8
111 #define UNIFY_ALLOW_OUTER_LEVEL 16
112 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
113 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
116 tbr_incomplete_type,
117 tbr_ambiguous_baseclass,
118 tbr_success
119 };
142 tree);
204 location_t);
212 /* Make the current scope suitable for access checking when we are
213 processing T. T can be FUNCTION_DECL for instantiated function
214 template, VAR_DECL for static member variable, or TYPE_DECL for
215 alias template (needed by instantiate_decl). */
217 static void
219 {
227 else
231 {
232 saved_access_scope = tree_cons
235 }
236 }
238 /* Restore the scope set up by push_access_scope. T is the node we
239 are processing. */
241 static void
243 {
245 {
248 }
252 else
254 }
256 /* Do any processing required when DECL (a member template
257 declaration) is finished. Returns the TEMPLATE_DECL corresponding
258 to DECL, unless it is a specialization, in which case the DECL
259 itself is returned. */
261 tree
263 {
270 {
271 tree type;
279 {
283 }
285 }
289 {
291 {
294 }
295 else
297 }
298 else
302 }
304 /* Create a template info node. */
306 tree
308 {
313 }
315 /* Return the template info node corresponding to T, whatever T is. */
317 tree
319 {
340 }
342 /* Returns the template nesting level of the indicated class TYPE.
344 For example, in:
345 template <class T>
346 struct A
347 {
348 template <class U>
349 struct B {};
350 };
352 A<T>::B<U> has depth two, while A<T> has depth one.
353 Both A<T>::B<int> and A<int>::B<U> have depth one, if
354 they are instantiations, not specializations.
356 This function is guaranteed to return 0 if passed NULL_TREE so
357 that, for example, `template_class_depth (current_class_type)' is
358 always safe. */
360 int
362 {
369 {
375 }
378 }
380 /* Subroutine of maybe_begin_member_template_processing.
381 Returns true if processing DECL needs us to push template parms. */
383 static bool
385 {
391 }
393 /* Subroutine of maybe_begin_member_template_processing.
394 Push the template parms in PARMS, starting from LEVELS steps into the
395 chain, and ending at the beginning, since template parms are listed
396 innermost first. */
398 static void
400 {
408 current_template_parms
414 NULL);
416 {
425 {
432 {
433 /* Make a CONST_DECL as is done in process_template_parm.
434 It is ugly that we recreate this here; the original
435 version built in process_template_parm is no longer
436 available. */
446 }
451 }
452 }
453 }
455 /* Restore the template parameter context for a member template, a
456 friend template defined in a class definition, or a non-template
457 member of template class. */
459 void
461 {
462 tree parms;
467 {
470 /* Disregard full specializations (c++/60999). */
473 }
476 {
481 {
484 }
487 }
489 /* Remember how many levels of template parameters we pushed so that
490 we can pop them later. */
492 }
494 /* Undo the effects of maybe_begin_member_template_processing. */
496 void
498 {
507 {
511 }
512 }
514 /* Return a new template argument vector which contains all of ARGS,
515 but has as its innermost set of arguments the EXTRA_ARGS. */
517 static tree
519 {
520 tree new_args;
538 }
540 /* Like add_to_template_args, but only the outermost ARGS are added to
541 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
542 (EXTRA_ARGS) levels are added. This function is used to combine
543 the template arguments from a partial instantiation with the
544 template arguments used to attain the full instantiation from the
545 partial instantiation. */
547 static tree
549 {
550 tree new_args;
552 /* If there are more levels of EXTRA_ARGS than there are ARGS,
553 something very fishy is going on. */
556 /* If *all* the new arguments will be the EXTRA_ARGS, just return
557 them. */
561 /* For the moment, we make ARGS look like it contains fewer levels. */
566 /* Now, we restore ARGS to its full dimensions. */
570 }
572 /* Return the N levels of innermost template arguments from the ARGS. */
574 tree
576 {
577 tree new_args;
583 /* If N is 1, just return the innermost set of template arguments. */
587 /* If we're not removing anything, just return the arguments we were
588 given. */
594 /* Make a new set of arguments, not containing the outer arguments. */
601 }
603 /* The inverse of get_innermost_template_args: Return all but the innermost
604 EXTRA_LEVELS levels of template arguments from the ARGS. */
606 static tree
608 {
609 tree new_args;
615 /* If N is 1, just return the outermost set of template arguments. */
619 /* If we're not removing anything, just return the arguments we were
620 given. */
625 /* Make a new set of arguments, not containing the inner arguments. */
632 }
634 /* We've got a template header coming up; push to a new level for storing
635 the parms. */
637 void
639 {
640 /* We use a non-tag-transparent scope here, which causes pushtag to
641 put tags in this scope, rather than in the enclosing class or
642 namespace scope. This is the right thing, since we want
643 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
644 global template class, push_template_decl handles putting the
645 TEMPLATE_DECL into top-level scope. For a nested template class,
646 e.g.:
648 template <class T> struct S1 {
649 template <class T> struct S2 {};
650 };
652 pushtag contains special code to call pushdecl_with_scope on the
653 TEMPLATE_DECL for S2. */
658 }
660 /* This routine is called when a specialization is declared. If it is
661 invalid to declare a specialization here, an error is reported and
662 false is returned, otherwise this routine will return true. */
664 static bool
666 {
669 /* [temp.expl.spec]
671 An explicit specialization shall be declared in the namespace of
672 which the template is a member, or, for member templates, in the
673 namespace of which the enclosing class or enclosing class
674 template is a member. An explicit specialization of a member
675 function, member class or static data member of a class template
676 shall be declared in the namespace of which the class template
677 is a member. */
679 {
682 }
684 /* [temp.expl.spec]
686 In an explicit specialization declaration for a member of a class
687 template or a member template that appears in namespace scope,
688 the member template and some of its enclosing class templates may
689 remain unspecialized, except that the declaration shall not
690 explicitly specialize a class member template if its enclosing
691 class templates are not explicitly specialized as well. */
693 {
696 }
699 }
701 /* We've just seen template <>. */
703 bool
705 {
709 }
711 /* Called at then end of processing a declaration preceded by
712 template<>. */
714 void
716 {
719 }
721 /* Any template <>'s that we have seen thus far are not referring to a
722 function specialization. */
724 void
726 {
729 }
731 /* We've just seen a template header. If SPECIALIZATION is nonzero,
732 it was of the form template <>. */
734 static void
736 {
738 template_header_count++;
739 }
741 /* We're beginning an explicit instantiation. */
743 void
745 {
748 }
751 void
753 {
756 }
758 /* An explicit specialization or partial specialization of TMPL is being
759 declared. Check that the namespace in which the specialization is
760 occurring is permissible. Returns false iff it is invalid to
761 specialize TMPL in the current namespace. */
763 static bool
765 {
768 /* [tmpl.expl.spec]
770 An explicit specialization shall be declared in the namespace of
771 which the template is a member, or, for member templates, in the
772 namespace of which the enclosing class or enclosing class
773 template is a member. An explicit specialization of a member
774 function, member class or static data member of a class template
775 shall be declared in the namespace of which the class template is
776 a member. */
779 {
782 }
784 /* Same or super-using namespace. */
786 else
787 {
791 }
792 }
794 /* SPEC is an explicit instantiation. Check that it is valid to
795 perform this explicit instantiation in the current namespace. */
797 static void
799 {
800 tree ns;
802 /* DR 275: An explicit instantiation shall appear in an enclosing
803 namespace of its template. */
809 }
811 /* The TYPE is being declared. If it is a template type, that means it
812 is a partial specialization. Do appropriate error-checking. */
814 tree
816 {
817 tree context;
822 /* A lambda that appears in specialization context is not itself a
823 specialization. */
828 {
832 }
837 {
842 else
845 }
847 {
848 /* This is for ordinary explicit specialization and partial
849 specialization of a template class such as:
851 template <> class C<int>;
853 or:
855 template <class T> class C<T*>;
857 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
861 {
868 {
872 }
873 }
879 /* Trying to define a specialization either without a template<> header
880 or in an inappropriate place. We've already given an error, so just
881 bail now so we don't actually define the specialization. */
883 }
889 {
890 /* This is for an explicit specialization of member class
891 template according to [temp.expl.spec/18]:
893 template <> template <class U> class C<int>::D;
895 The context `C<int>' must be an implicit instantiation.
896 Otherwise this is just a member class template declared
897 earlier like:
899 template <> class C<int> { template <class U> class D; };
900 template <> template <class U> class C<int>::D;
902 In the first case, `C<int>::D' is a specialization of `C<T>::D'
903 while in the second case, `C<int>::D' is a primary template
904 and `C<T>::D' may not exist. */
908 {
909 tree t;
914 {
917 }
919 /* Check for invalid specialization after instantiation:
921 template <> template <> class C<int>::D<int>;
922 template <> template <class U> class C<int>::D; */
926 {
930 {
931 /* We already have a full specialization of this partial
932 instantiation, or a full specialization has been
933 looked up but not instantiated. Reassign it to the
934 new member specialization template. */
935 spec_entry elt;
947 spec_entry **slot
952 }
953 else
954 /* But if we've had an implicit instantiation, that's a
955 problem ([temp.expl.spec]/6). */
958 }
960 /* Mark TYPE as a specialization. And as a result, we only
961 have one level of template argument for the innermost
962 class template. */
967 }
968 }
970 {
971 /* Someday C++0x may allow for enum template specialization. */
976 else
977 {
980 }
981 }
984 }
986 /* Returns nonzero if we can optimize the retrieval of specializations
987 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
988 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
992 {
995 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
996 parameter. */
998 /* The optimized lookup depends on the fact that the
999 template arguments for the member function template apply
1000 purely to the containing class, which is not true if the
1001 containing class is an explicit or partial
1002 specialization. */
1006 /* It is possible to have a template that is not a member
1007 template and is not a member of a template class:
1009 template <typename T>
1010 struct S { friend A::f(); };
1012 Here, the friend function is a template, but the context does
1013 not have template information. The optimized lookup relies
1014 on having ARGS be the template arguments for both the class
1015 and the function template. */
1017 }
1019 /* Retrieve the specialization (in the sense of [temp.spec] - a
1020 specialization is either an instantiation or an explicit
1021 specialization) of TMPL for the given template ARGS. If there is
1022 no such specialization, return NULL_TREE. The ARGS are a vector of
1023 arguments, or a vector of vectors of arguments, in the case of
1024 templates with more than one level of parameters.
1026 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1027 then we search for a partial specialization matching ARGS. This
1028 parameter is ignored if TMPL is not a class template.
1030 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1031 result is a NONTYPE_ARGUMENT_PACK. */
1033 static tree
1035 {
1045 /* There should be as many levels of arguments as there are
1046 levels of parameters. */
1053 {
1054 tree class_template;
1055 tree class_specialization;
1057 tree fns;
1060 /* The template arguments actually apply to the containing
1061 class. Find the class specialization with those
1062 arguments. */
1064 class_specialization
1068 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1069 for the specialization. */
1073 /* Iterate through the methods with the indicated name, looking
1074 for the one that has an instance of TMPL. */
1077 {
1080 /* using-declarations can add base methods to the method vec,
1081 and we don't want those here. */
1084 }
1086 }
1087 else
1088 {
1090 spec_entry elt;
1099 else
1107 }
1110 }
1112 /* Like retrieve_specialization, but for local declarations. */
1114 static tree
1116 {
1122 }
1124 /* Returns nonzero iff DECL is a specialization of TMPL. */
1126 int
1128 {
1129 tree t;
1132 {
1138 }
1139 else
1140 {
1149 }
1152 }
1154 /* Returns nonzero iff DECL is a specialization of friend declaration
1155 FRIEND_DECL according to [temp.friend]. */
1157 bool
1159 {
1166 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1167 of a template class, we want to check if DECL is a specialization
1168 if this. */
1172 {
1173 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1176 }
1181 /* There is nothing to do if this is not a template friend. */
1188 /* [temp.friend/6]
1189 A member of a class template may be declared to be a friend of a
1190 non-template class. In this case, the corresponding member of
1191 every specialization of the class template is a friend of the
1192 class granting friendship.
1194 For example, given a template friend declaration
1196 template <class T> friend void A<T>::f();
1198 the member function below is considered a friend
1200 template <> struct A<int> {
1201 void f();
1202 };
1204 For this type of template friend, TEMPLATE_DEPTH below will be
1205 nonzero. To determine if DECL is a friend of FRIEND, we first
1206 check if the enclosing class is a specialization of another. */
1213 {
1214 /* Next, we check the members themselves. In order to handle
1215 a few tricky cases, such as when FRIEND_DECL's are
1217 template <class T> friend void A<T>::g(T t);
1218 template <class T> template <T t> friend void A<T>::h();
1220 and DECL's are
1222 void A<int>::g(int);
1223 template <int> void A<int>::h();
1225 we need to figure out ARGS, the template arguments from
1226 the context of DECL. This is required for template substitution
1227 of `T' in the function parameter of `g' and template parameter
1228 of `h' in the above examples. Here ARGS corresponds to `int'. */
1235 {
1237 {
1240 else
1242 current_depth++;
1243 }
1245 }
1248 {
1250 tree friend_type;
1251 tree decl_type;
1252 tree friend_args_type;
1253 tree decl_args_type;
1255 /* Make sure that both DECL and FRIEND_DECL are templates or
1256 non-templates. */
1262 {
1263 /* If both are templates, check template parameter list. */
1264 tree friend_parms
1269 friend_parms))
1273 }
1274 else
1282 /* Check if return types match. */
1286 /* Check if function parameter types match, ignoring the
1287 `this' parameter. */
1296 }
1297 else
1298 {
1299 /* DECL is a TYPE_DECL */
1303 /* Make sure that both DECL and FRIEND_DECL are templates or
1304 non-templates. */
1305 is_template
1312 {
1313 tree friend_parms;
1314 /* If both are templates, check the name of the two
1315 TEMPLATE_DECL's first because is_friend didn't. */
1320 /* Now check template parameter list. */
1321 friend_parms
1324 return comp_template_parms
1326 friend_parms);
1327 }
1328 else
1331 }
1332 }
1334 }
1336 /* Register the specialization SPEC as a specialization of TMPL with
1337 the indicated ARGS. IS_FRIEND indicates whether the specialization
1338 is actually just a friend declaration. Returns SPEC, or an
1339 equivalent prior declaration, if available.
1341 We also store instantiations of field packs in the hash table, even
1342 though they are not themselves templates, to make lookup easier. */
1344 static tree
1346 hashval_t hash)
1347 {
1348 tree fn;
1350 spec_entry elt;
1358 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1359 register it; we want the corresponding TEMPLATE_DECL instead.
1360 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1361 the more obvious `uses_template_parms (spec)' to avoid problems
1362 with default function arguments. In particular, given
1363 something like this:
1365 template <class T> void f(T t1, T t = T())
1367 the default argument expression is not substituted for in an
1368 instantiation unless and until it is actually needed. */
1372 /* We don't put these specializations in the hash table, but we might
1373 want to give an error about a mismatch. */
1375 else
1376 {
1384 slot =
1388 else
1390 }
1392 /* We can sometimes try to re-register a specialization that we've
1393 already got. In particular, regenerate_decl_from_template calls
1394 duplicate_decls which will update the specialization list. But,
1395 we'll still get called again here anyhow. It's more convenient
1396 to simply allow this than to try to prevent it. */
1400 {
1402 {
1405 {
1407 fn);
1409 }
1410 else
1411 {
1412 tree clone;
1413 /* This situation should occur only if the first
1414 specialization is an implicit instantiation, the
1415 second is an explicit specialization, and the
1416 implicit instantiation has not yet been used. That
1417 situation can occur if we have implicitly
1418 instantiated a member function and then specialized
1419 it later.
1421 We can also wind up here if a friend declaration that
1422 looked like an instantiation turns out to be a
1423 specialization:
1425 template <class T> void foo(T);
1426 class S { friend void foo<>(int) };
1427 template <> void foo(int);
1429 We transform the existing DECL in place so that any
1430 pointers to it become pointers to the updated
1431 declaration.
1433 If there was a definition for the template, but not
1434 for the specialization, we want this to look as if
1435 there were no definition, and vice versa. */
1438 /* The call to duplicate_decls will have applied
1439 [temp.expl.spec]:
1441 An explicit specialization of a function template
1442 is inline only if it is explicitly declared to be,
1443 and independently of whether its function template
1444 is.
1446 to the primary function; now copy the inline bits to
1447 the various clones. */
1449 {
1456 }
1460 }
1461 }
1463 {
1465 /* Dup decl failed, but this is a new definition. Set the
1466 line number so any errors match this new
1467 definition. */
1471 }
1472 }
1476 /* A specialization must be declared in the same namespace as the
1477 template it is specializing. */
1483 {
1491 /* TMPL is a forward declaration of a template function; keep a list
1492 of all specializations in case we need to reassign them to a friend
1493 template later in tsubst_friend_function. */
1496 }
1499 }
1501 /* Returns true iff two spec_entry nodes are equivalent. Only compares the
1502 TMPL and ARGS members, ignores SPEC. */
1506 bool
1508 {
1517 }
1519 /* Returns a hash for a template TMPL and template arguments ARGS. */
1521 static hashval_t
1523 {
1526 }
1528 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1529 ignoring SPEC. */
1531 hashval_t
1533 {
1535 }
1537 /* Recursively calculate a hash value for a template argument ARG, for use
1538 in the hash tables of template specializations. */
1540 hashval_t
1542 {
1554 /* We can get one of these when re-hashing a previous entry in the middle
1555 of substituting into a pack expansion. Just look through it. */
1564 {
1572 {
1577 }
1599 {
1603 {
1606 }
1608 }
1612 {
1615 }
1626 val = iterative_hash_template_arg
1638 val);
1640 val);
1649 /* A lambda can't appear in a template arg, but don't crash on
1650 erroneous input. */
1662 /* Now hash operands as usual. */
1667 }
1670 {
1674 val);
1677 /* Otherwise just compare the types during lookup. */
1686 {
1691 }
1692 }
1695 }
1697 /* Unregister the specialization SPEC as a specialization of TMPL.
1698 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1699 if the SPEC was listed as a specialization of TMPL.
1701 Note that SPEC has been ggc_freed, so we can't look inside it. */
1703 bool
1705 {
1707 spec_entry elt;
1715 {
1720 }
1723 }
1725 /* Like register_specialization, but for local declarations. We are
1726 registering SPEC, an instantiation of TMPL. */
1728 static void
1730 {
1732 }
1734 /* TYPE is a class type. Returns true if TYPE is an explicitly
1735 specialized class. */
1737 bool
1739 {
1743 }
1745 /* Print the list of functions at FNS, going through all the overloads
1746 for each element of the list. Alternatively, FNS can not be a
1747 TREE_LIST, in which case it will be printed together with all the
1748 overloads.
1750 MORE and *STR should respectively be FALSE and NULL when the function
1751 is called from the outside. They are used internally on recursive
1752 calls. print_candidates manages the two parameters and leaves NULL
1753 in *STR when it ends. */
1755 static void
1757 {
1763 {
1767 }
1768 else
1769 {
1772 {
1773 /* Pick the prefix string. */
1775 {
1779 }
1783 }
1786 }
1789 {
1792 }
1793 }
1795 /* Print the list of candidate FNS in an error message. FNS can also
1796 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1798 void
1800 {
1804 }
1806 /* Returns the template (one of the functions given by TEMPLATE_ID)
1807 which can be specialized to match the indicated DECL with the
1808 explicit template args given in TEMPLATE_ID. The DECL may be
1809 NULL_TREE if none is available. In that case, the functions in
1810 TEMPLATE_ID are non-members.
1812 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1813 specialization of a member template.
1815 The TEMPLATE_COUNT is the number of references to qualifying
1816 template classes that appeared in the name of the function. See
1817 check_explicit_specialization for a more accurate description.
1819 TSK indicates what kind of template declaration (if any) is being
1820 declared. TSK_TEMPLATE indicates that the declaration given by
1821 DECL, though a FUNCTION_DECL, has template parameters, and is
1822 therefore a template function.
1824 The template args (those explicitly specified and those deduced)
1825 are output in a newly created vector *TARGS_OUT.
1827 If it is impossible to determine the result, an error message is
1828 issued. The error_mark_node is returned to indicate failure. */
1830 static tree
1832 tree decl,
1836 tmpl_spec_kind tsk)
1837 {
1838 tree fns;
1839 tree targs;
1840 tree explicit_targs;
1842 /* A TREE_LIST of templates of which DECL may be a specialization.
1843 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1844 corresponding TREE_PURPOSE is the set of template arguments that,
1845 when used to instantiate the template, would produce a function
1846 with the signature of DECL. */
1856 /* We shouldn't be specializing a member template of an
1857 unspecialized class template; we already gave an error in
1858 check_specialization_scope, now avoid crashing. */
1861 {
1864 }
1872 /* Check for baselinks. */
1877 {
1880 }
1882 {
1885 }
1887 /* Count the number of template headers specified for this
1888 specialization. */
1898 {
1902 {
1903 tree decl_arg_types;
1904 tree fn_arg_types;
1905 tree insttype;
1907 /* In case of explicit specialization, we need to check if
1908 the number of template headers appearing in the specialization
1909 is correct. This is usually done in check_explicit_specialization,
1910 but the check done there cannot be exhaustive when specializing
1911 member functions. Consider the following code:
1913 template <> void A<int>::f(int);
1914 template <> template <> void A<int>::f(int);
1916 Assuming that A<int> is not itself an explicit specialization
1917 already, the first line specializes "f" which is a non-template
1918 member function, whilst the second line specializes "f" which
1919 is a template member function. So both lines are syntactically
1920 correct, and check_explicit_specialization does not reject
1921 them.
1923 Here, we can do better, as we are matching the specialization
1924 against the declarations. We count the number of template
1925 headers, and we check if they match TEMPLATE_COUNT + 1
1926 (TEMPLATE_COUNT is the number of qualifying template classes,
1927 plus there must be another header for the member template
1928 itself).
1930 Notice that if header_count is zero, this is not a
1931 specialization but rather a template instantiation, so there
1932 is no check we can perform here. */
1936 /* Check that the number of template arguments at the
1937 innermost level for DECL is the same as for FN. */
1945 /* DECL might be a specialization of FN. */
1949 /* For a non-static member function, we need to make sure
1950 that the const qualification is the same. Since
1951 get_bindings does not try to merge the "this" parameter,
1952 we must do the comparison explicitly. */
1958 /* Skip the "this" parameter and, for constructors of
1959 classes with virtual bases, the VTT parameter. A
1960 full specialization of a constructor will have a VTT
1961 parameter, but a template never will. */
1962 decl_arg_types
1964 fn_arg_types
1967 /* Function templates cannot be specializations; there are
1968 no partial specializations of functions. Therefore, if
1969 the type of DECL does not match FN, there is no
1970 match. */
1972 {
1976 }
1978 /* See whether this function might be a specialization of this
1979 template. Suppress access control because we might be trying
1980 to make this specialization a friend, and we have already done
1981 access control for the declaration of the specialization. */
1987 /* We cannot deduce template arguments that when used to
1988 specialize TMPL will produce DECL. */
1991 /* Make sure that the deduced arguments actually work. */
1995 fn_arg_types
2000 /* Save this template, and the arguments deduced. */
2002 }
2004 /* FN is an ordinary member function, and we need a
2005 specialization of a member template. */
2006 ;
2008 /* We can get IDENTIFIER_NODEs here in certain erroneous
2009 cases. */
2010 ;
2012 /* This is just an ordinary non-member function. Nothing can
2013 be a specialization of that. */
2014 ;
2016 /* Cannot specialize functions that are created implicitly. */
2017 ;
2018 else
2019 {
2020 tree decl_arg_types;
2022 /* This is an ordinary member function. However, since
2023 we're here, we can assume its enclosing class is a
2024 template class. For example,
2026 template <typename T> struct S { void f(); };
2027 template <> void S<int>::f() {}
2029 Here, S<int>::f is a non-template, but S<int> is a
2030 template class. If FN has the same type as DECL, we
2031 might be in business. */
2034 /* Its enclosing class is an explicit specialization
2035 of a template class. This is not a candidate. */
2040 /* The return types differ. */
2043 /* Adjust the type of DECL in case FN is a static member. */
2050 decl_arg_types))
2051 /* They match! */
2053 }
2054 }
2057 {
2058 /* We have:
2060 [temp.expl.spec]
2062 It is possible for a specialization with a given function
2063 signature to be instantiated from more than one function
2064 template. In such cases, explicit specification of the
2065 template arguments must be used to uniquely identify the
2066 function template specialization being specialized.
2068 Note that here, there's no suggestion that we're supposed to
2069 determine which of the candidate templates is most
2070 specialized. However, we, also have:
2072 [temp.func.order]
2074 Partial ordering of overloaded function template
2075 declarations is used in the following contexts to select
2076 the function template to which a function template
2077 specialization refers:
2079 -- when an explicit specialization refers to a function
2080 template.
2082 So, we do use the partial ordering rules, at least for now.
2083 This extension can only serve to make invalid programs valid,
2084 so it's safe. And, there is strong anecdotal evidence that
2085 the committee intended the partial ordering rules to apply;
2086 the EDG front end has that behavior, and John Spicer claims
2087 that the committee simply forgot to delete the wording in
2088 [temp.expl.spec]. */
2091 {
2094 }
2095 }
2098 {
2106 }
2110 {
2116 }
2118 /* We have one, and exactly one, match. */
2120 {
2123 /* DECL is a re-declaration or partial instantiation of a template
2124 function. */
2127 /* It was a specialization of an ordinary member function in a
2128 template class. */
2130 }
2132 /* It was a specialization of a template. */
2135 {
2140 }
2141 else
2144 }
2146 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2147 but with the default argument values filled in from those in the
2148 TMPL_TYPES. */
2150 static tree
2152 tree tmpl_types)
2153 {
2154 tree new_spec_types;
2162 /* Substitute into the rest of the list. */
2163 new_spec_types =
2167 /* Add the default argument for this parameter. */
2170 new_spec_types);
2171 }
2173 /* DECL is an explicit specialization. Replicate default arguments
2174 from the template it specializes. (That way, code like:
2176 template <class T> void f(T = 3);
2177 template <> void f(double);
2178 void g () { f (); }
2180 works, as required.) An alternative approach would be to look up
2181 the correct default arguments at the call-site, but this approach
2182 is consistent with how implicit instantiations are handled. */
2184 static void
2186 {
2187 tree tmpl;
2188 tree spec_types;
2189 tree tmpl_types;
2190 tree new_spec_types;
2191 tree old_type;
2192 tree new_type;
2193 tree t;
2198 /* See if there's anything we need to do. */
2211 {
2212 /* Remove the this pointer, but remember the object's type for
2213 CV quals. */
2219 {
2220 /* DECL may contain more parameters than TMPL due to the extra
2221 in-charge parameter in constructors and destructors. */
2224 }
2226 {
2229 }
2230 }
2232 /* Compute the merged default arguments. */
2233 new_spec_types =
2236 /* Compute the new FUNCTION_TYPE. */
2238 {
2242 new_spec_types);
2245 /* Put the in-charge parameter back. */
2248 new_spec_types);
2252 new_spec_types);
2253 }
2254 else
2256 new_spec_types);
2266 }
2268 /* Return the number of template headers we expect to see for a definition
2269 or specialization of CTYPE or one of its non-template members. */
2271 int
2273 {
2277 {
2278 /* You're supposed to have one `template <...>' for every
2279 template class, but you don't need one for a full
2280 specialization. For example:
2282 template <class T> struct S{};
2283 template <> struct S<int> { void f(); };
2284 void S<int>::f () {}
2286 is correct; there shouldn't be a `template <>' for the
2287 definition of `S<int>::f'. */
2289 /* If CTYPE does not have template information of any
2290 kind, then it is not a template, nor is it nested
2291 within a template. */
2299 }
2302 }
2304 /* Do a simple sanity check on the template headers that precede the
2305 variable declaration DECL. */
2307 void
2309 {
2314 {
2317 "variable templates only available with "
2320 // Namespace-scope variable templates should have a template header.
2322 }
2324 {
2331 "members of an explicitly specialized class are defined "
2333 }
2334 }
2336 /* Check to see if the function just declared, as indicated in
2337 DECLARATOR, and in DECL, is a specialization of a function
2338 template. We may also discover that the declaration is an explicit
2339 instantiation at this point.
2341 Returns DECL, or an equivalent declaration that should be used
2342 instead if all goes well. Issues an error message if something is
2343 amiss. Returns error_mark_node if the error is not easily
2344 recoverable.
2346 FLAGS is a bitmask consisting of the following flags:
2348 2: The function has a definition.
2349 4: The function is a friend.
2351 The TEMPLATE_COUNT is the number of references to qualifying
2352 template classes that appeared in the name of the function. For
2353 example, in
2355 template <class T> struct S { void f(); };
2356 void S<int>::f();
2358 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2359 classes are not counted in the TEMPLATE_COUNT, so that in
2361 template <class T> struct S {};
2362 template <> struct S<int> { void f(); }
2363 template <> void S<int>::f();
2365 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2366 invalid; there should be no template <>.)
2368 If the function is a specialization, it is marked as such via
2369 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2370 is set up correctly, and it is added to the list of specializations
2371 for that template. */
2373 tree
2375 tree decl,
2378 {
2386 tmpl_spec_kind tsk;
2389 {
2392 else
2394 }
2395 else
2399 {
2402 {
2405 }
2407 {
2409 /* This could be something like:
2411 template <class T> void f(T);
2412 class S { friend void f<>(int); } */
2414 else
2415 {
2416 /* This case handles bogus declarations like template <>
2417 template <class T> void f<int>(); */
2420 declarator);
2422 }
2423 }
2427 /* The error has already been reported in
2428 check_specialization_scope. */
2434 /* Fall through. */
2447 decl);
2450 else
2454 /* Fall through. */
2457 /* In cases like template<> constexpr bool v = true;
2458 We'll give an error in check_template_variable. */
2464 else
2470 {
2471 /* This case handles bogus declarations like template <>
2472 template <class T> void f<int>(); */
2477 else
2479 declarator);
2481 }
2484 /* This is a specialization of a member template, without
2485 specialization the containing class. Something like:
2487 template <class T> struct S {
2488 template <class U> void f (U);
2489 };
2490 template <> template <class U> void S<int>::f(U) {}
2492 That's a specialization -- but of the entire template. */
2498 }
2501 /* This doesn't apply to variable templates. */
2504 {
2508 {
2512 }
2513 }
2516 {
2520 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2522 {
2523 tree fns;
2528 else
2529 {
2530 /* If there is no class context, the explicit instantiation
2531 must be at namespace scope. */
2534 /* Find the namespace binding, using the declaration
2535 context. */
2539 {
2542 }
2543 else
2544 {
2550 }
2551 }
2554 }
2560 {
2562 /* A specialization in class scope. This is invalid,
2563 but the error will already have been flagged by
2564 check_specialization_scope. */
2566 else
2567 {
2568 /* It's not valid to write an explicit instantiation in
2569 class scope, e.g.:
2571 class C { template void f(); }
2573 This case is caught by the parser. However, on
2574 something like:
2576 template class C { void f(); };
2578 (which is invalid) we can get here. The error will be
2579 issued later. */
2580 ;
2581 }
2584 }
2587 {
2588 // Ignore variable templates.
2592 /* Find the list of functions in ctype that have the same
2593 name as the declared function. */
2599 {
2604 {
2605 /* From [temp.expl.spec]:
2607 If such an explicit specialization for the member
2608 of a class template names an implicitly-declared
2609 special member function (clause _special_), the
2610 program is ill-formed.
2612 Similar language is found in [temp.explicit]. */
2615 }
2618 }
2621 {
2625 }
2626 else
2627 {
2629 tree ovl;
2631 /* For a type-conversion operator, we cannot do a
2632 name-based lookup. We might be looking for `operator
2633 int' which will be a specialization of `operator T'.
2634 So, we find *all* the conversion operators, and then
2635 select from them. */
2643 {
2645 /* There are no more conversion functions. */
2648 /* Glue all these conversion functions together
2649 with those we already have. */
2652 }
2653 }
2656 {
2659 }
2660 else
2662 }
2664 /* Figure out what exactly is being specialized at this point.
2665 Note that for an explicit instantiation, even one for a
2666 member function, we cannot tell apriori whether the
2667 instantiation is for a member template, or just a member
2668 function of a template class. Even if a member template is
2669 being instantiated, the member template arguments may be
2670 elided if they can be deduced from the rest of the
2671 declaration. */
2674 member_specialization,
2675 template_count,
2676 tsk);
2679 /* We couldn't figure out what this declaration was
2680 specializing. */
2682 else
2683 {
2687 {
2688 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2689 is done by do_decl_instantiation later. */
2695 {
2696 /* If TMPL is not the most general template (for
2697 example, if TMPL is a friend template that is
2698 injected into namespace scope), then there will
2699 be too many levels of TARGS. Remove some of them
2700 here. */
2702 tree new_targs;
2709 }
2712 }
2714 /* If we thought that the DECL was a member function, but it
2715 turns out to be specializing a static member function,
2716 make DECL a static member function as well. */
2722 /* If this is a specialization of a member template of a
2723 template class, we want to return the TEMPLATE_DECL, not
2724 the specialization of it. */
2726 {
2731 {
2732 tree parm;
2736 /* We want to use the argument list specified in the
2737 definition, not in the original declaration. */
2742 }
2745 }
2747 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2750 /* Inherit default function arguments from the template
2751 DECL is specializing. */
2755 /* This specialization has the same protection as the
2756 template it specializes. */
2760 /* 7.1.1-1 [dcl.stc]
2762 A storage-class-specifier shall not be specified in an
2763 explicit specialization...
2765 The parser rejects these, so unless action is taken here,
2766 explicit function specializations will always appear with
2767 global linkage.
2769 The action recommended by the C++ CWG in response to C++
2770 defect report 605 is to make the storage class and linkage
2771 of the explicit specialization match the templated function:
2773 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2774 */
2776 {
2780 /* This specialization has the same linkage and visibility as
2781 the function template it specializes. */
2784 {
2787 }
2790 {
2793 }
2794 }
2796 /* If DECL is a friend declaration, declared using an
2797 unqualified name, the namespace associated with DECL may
2798 have been set incorrectly. For example, in:
2800 template <typename T> void f(T);
2801 namespace N {
2802 struct S { friend void f<int>(int); }
2803 }
2805 we will have set the DECL_CONTEXT for the friend
2806 declaration to N, rather than to the global namespace. */
2811 /* This is not really a declaration of a specialization.
2812 It's just the name of an instantiation. But, it's not
2813 a request for an instantiation, either. */
2816 /* A specialization is not necessarily COMDAT. */
2822 /* Register this specialization so that we can find it
2823 again. */
2826 /* A 'structor should already have clones. */
2832 }
2833 }
2836 }
2838 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2839 parameters. These are represented in the same format used for
2840 DECL_TEMPLATE_PARMS. */
2842 int
2844 {
2845 const_tree p1;
2846 const_tree p2;
2854 {
2866 {
2870 /* If either of the template parameters are invalid, assume
2871 they match for the sake of error recovery. */
2884 }
2885 }
2888 /* One set of parameters has more parameters lists than the
2889 other. */
2893 }
2895 /* Determine whether PARM is a parameter pack. */
2897 bool
2899 {
2900 /* Determine if we have a non-type template parameter pack. */
2907 /* If this is a list of template parameters, we could get a
2908 TYPE_DECL or a TEMPLATE_DECL. */
2912 /* Otherwise it must be a type template parameter. */
2916 }
2918 /* Determine if T is a function parameter pack. */
2920 bool
2922 {
2926 }
2928 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
2929 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
2931 tree
2933 {
2940 }
2942 /* Return true iff the function parameter PARAM_DECL was expanded
2943 from the function parameter pack PACK. */
2945 bool
2947 {
2952 /* The parameter pack and its pack arguments have the same
2953 DECL_PARM_INDEX. */
2955 }
2957 /* Determine whether ARGS describes a variadic template args list,
2958 i.e., one that is terminated by a template argument pack. */
2960 static bool
2962 {
2964 tree last_parm;
2978 }
2980 /* Generate a new name for the parameter pack name NAME (an
2981 IDENTIFIER_NODE) that incorporates its */
2983 static tree
2985 {
2986 /* Munge the name to include the parameter index. */
2987 #define NUMBUF_LEN 128
3001 }
3003 /* Return true if T is a primary function, class or alias template
3004 instantiation. */
3006 bool
3008 {
3022 }
3024 /* Return true if PARM is a template template parameter. */
3026 bool
3028 {
3030 }
3032 /* Return true iff PARM is a DECL representing a type template
3033 parameter. */
3035 bool
3037 {
3042 }
3044 /* Return the template parameters of T if T is a
3045 primary template instantiation, NULL otherwise. */
3047 tree
3049 {
3054 parms = INNERMOST_TEMPLATE_PARMS
3058 }
3060 /* Return the template parameters of the LEVELth level from the full list
3061 of template parameters PARMS. */
3063 tree
3065 {
3066 tree p;
3077 }
3079 /* Returns the template arguments of T if T is a template instantiation,
3080 NULL otherwise. */
3082 tree
3084 {
3092 }
3094 /* Return the argument pack elements of T if T is a template argument pack,
3095 NULL otherwise. */
3097 tree
3099 {
3105 }
3107 /* Structure used to track the progress of find_parameter_packs_r. */
3108 struct find_parameter_pack_data
3109 {
3110 /* TREE_LIST that will contain all of the parameter packs found by
3111 the traversal. */
3114 /* Set of AST nodes that have been visited by the traversal. */
3116 };
3118 /* Identifies all of the argument packs that occur in a template
3119 argument and appends them to the TREE_LIST inside DATA, which is a
3120 find_parameter_pack_data structure. This is a subroutine of
3121 make_pack_expansion and uses_parameter_packs. */
3122 static tree
3124 {
3130 /* Handle type aliases/typedefs. */
3132 {
3139 }
3141 /* Identify whether this is a parameter pack or not. */
3143 {
3159 {
3160 /* We don't want to walk into the type of a PARM_DECL,
3161 because we don't want to see the type parameter pack. */
3164 }
3167 /* Look through a lambda capture proxy to the field pack. */
3170 {
3176 }
3183 /* Not a parameter pack. */
3185 }
3188 {
3189 /* Add this parameter pack to the list. */
3191 }
3197 /* This switch statement will return immediately if we don't find a
3198 parameter pack. */
3200 {
3205 /* Check the template itself. */
3208 /* Check the template arguments. */
3224 /* Fall through. */
3266 }
3269 }
3271 /* Determines if the expression or type T uses any parameter packs. */
3272 bool
3274 {
3282 }
3284 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3285 representation a base-class initializer into a parameter pack
3286 expansion. If all goes well, the resulting node will be an
3287 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3288 respectively. */
3289 tree
3291 {
3292 tree result;
3301 {
3302 /* The only time we will see a TREE_LIST here is for a base
3303 class initializer. In this case, the TREE_PURPOSE will be a
3304 _TYPE node (representing the base class expansion we're
3305 initializing) and the TREE_VALUE will be a TREE_LIST
3306 containing the initialization arguments.
3308 The resulting expansion looks somewhat different from most
3309 expansions. Rather than returning just one _EXPANSION, we
3310 return a TREE_LIST whose TREE_PURPOSE is a
3311 TYPE_PACK_EXPANSION containing the bases that will be
3312 initialized. The TREE_VALUE will be identical to the
3313 original TREE_VALUE, which is a list of arguments that will
3314 be passed to each base. We do not introduce any new pack
3315 expansion nodes into the TREE_VALUE (although it is possible
3316 that some already exist), because the TREE_PURPOSE and
3317 TREE_VALUE all need to be expanded together with the same
3318 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3319 resulting TREE_PURPOSE will mention the parameter packs in
3320 both the bases and the arguments to the bases. */
3321 tree purpose;
3322 tree value;
3325 /* Determine which parameter packs will be used by the base
3326 class expansion. */
3333 {
3337 }
3340 {
3341 /* Collect the sets of parameter packs used in each of the
3342 initialization arguments. */
3344 {
3345 /* Determine which parameter packs will be expanded in this
3346 argument. */
3349 }
3350 }
3354 /* Create the pack expansion type for the base type. */
3359 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3360 they will rarely be compared to anything. */
3364 }
3369 /* Build the PACK_EXPANSION_* node. */
3370 result = for_types
3375 {
3376 /* Propagate type and const-expression information. */
3379 }
3380 else
3381 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3382 they will rarely be compared to anything. */
3385 /* Determine which parameter packs will be expanded. */
3391 /* Make sure we found some parameter packs. */
3393 {
3396 else
3399 }
3405 }
3407 /* Checks T for any "bare" parameter packs, which have not yet been
3408 expanded, and issues an error if any are found. This operation can
3409 only be done on full expressions or types (e.g., an expression
3410 statement, "if" condition, etc.), because we could have expressions like:
3412 foo(f(g(h(args)))...)
3414 where "args" is a parameter pack. check_for_bare_parameter_packs
3415 should not be called for the subexpressions args, h(args),
3416 g(h(args)), or f(g(h(args))), because we would produce erroneous
3417 error messages.
3419 Returns TRUE and emits an error if there were bare parameter packs,
3420 returns FALSE otherwise. */
3421 bool
3423 {
3439 {
3442 {
3451 else
3456 else
3460 }
3463 }
3466 }
3468 /* Expand any parameter packs that occur in the template arguments in
3469 ARGS. */
3470 tree
3472 {
3478 /* First, determine if we need to expand anything, and the number of
3479 slots we'll need. */
3481 {
3486 {
3490 else
3492 }
3493 else
3494 {
3496 num_result_args++;
3497 }
3498 }
3500 /* If no expansion is necessary, we're done. */
3504 /* Expand arguments. */
3507 non_default_args_count =
3510 {
3513 {
3520 }
3521 else
3522 {
3525 }
3526 }
3530 }
3532 /* Checks if DECL shadows a template parameter.
3534 [temp.local]: A template-parameter shall not be redeclared within its
3535 scope (including nested scopes).
3537 Emits an error and returns TRUE if the DECL shadows a parameter,
3538 returns FALSE otherwise. */
3540 bool
3542 {
3543 tree olddecl;
3545 /* If we're not in a template, we can't possibly shadow a template
3546 parameter. */
3550 /* Figure out what we're shadowing. */
3555 /* If there's no previous binding for this name, we're not shadowing
3556 anything, let alone a template parameter. */
3560 /* If we're not shadowing a template parameter, we're done. Note
3561 that OLDDECL might be an OVERLOAD (or perhaps even an
3562 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3563 node. */
3567 /* We check for decl != olddecl to avoid bogus errors for using a
3568 name inside a class. We check TPFI to avoid duplicate errors for
3569 inline member templates. */
3575 /* Don't complain about the injected class name, as we've already
3576 complained about the class itself. */
3583 }
3585 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3586 ORIG_LEVEL, DECL, and TYPE. */
3588 static tree
3592 tree decl,
3593 tree type)
3594 {
3605 }
3607 /* Find the canonical type parameter for the given template type
3608 parameter. Returns the canonical type parameter, which may be TYPE
3609 if no such parameter existed. */
3611 static tree
3613 {
3614 tree list;
3628 else
3629 {
3634 }
3635 }
3637 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3638 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3639 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3640 new one is created. */
3642 static tree
3644 tsubst_flags_t complain)
3645 {
3650 {
3669 /* Template template parameters need this. */
3674 }
3677 }
3679 /* Process information from new template parameter PARM and append it
3680 to the LIST being built. This new parameter is a non-type
3681 parameter iff IS_NON_TYPE is true. This new parameter is a
3682 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3683 is in PARM_LOC. */
3685 tree
3688 {
3690 tree defval;
3697 {
3701 {
3705 else
3707 }
3710 }
3713 {
3719 {
3720 /* [temp.param]
3722 The top-level cv-qualifiers on the template-parameter are
3723 ignored when determining its type. */
3728 && !is_parameter_pack
3729 /* If we're in a nested template parameter list, the template
3730 template parameter could be a parameter pack. */
3732 {
3733 /* This template parameter is not a parameter pack, but it
3734 should be. Complain about "bare" parameter packs. */
3737 /* Recover by calling this a parameter pack. */
3739 }
3740 }
3742 /* A template parameter is not modifiable. */
3751 processing_template_decl,
3756 }
3757 else
3758 {
3759 tree t;
3763 {
3765 /* This is for distinguishing between real templates and template
3766 template parameters */
3770 }
3771 else
3772 {
3774 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3777 }
3784 processing_template_decl,
3788 }
3794 }
3796 /* The end of a template parameter list has been reached. Process the
3797 tree list into a parameter vector, converting each parameter into a more
3798 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3799 as PARM_DECLs. */
3801 tree
3803 {
3808 current_template_parms
3813 {
3817 }
3822 }
3824 /* end_template_decl is called after a template declaration is seen. */
3826 void
3828 {
3834 /* This matches the pushlevel in begin_template_parm_list. */
3839 }
3841 /* Takes a TREE_LIST representing a template parameter and convert it
3842 into an argument suitable to be passed to the type substitution
3843 functions. Note that If the TREE_LIST contains an error_mark
3844 node, the returned argument is error_mark_node. */
3846 static tree
3848 {
3861 {
3865 {
3866 /* Turn this argument into a TYPE_ARGUMENT_PACK
3867 with a single element, which expands T. */
3869 #ifdef ENABLE_CHECKING
3870 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3872 #endif
3877 }
3878 }
3879 else
3880 {
3884 {
3885 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3886 with a single element, which expands T. */
3889 #ifdef ENABLE_CHECKING
3890 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3892 #endif
3899 }
3900 else
3902 }
3904 }
3906 /* Given a set of template parameters, return them as a set of template
3907 arguments. The template parameters are represented as a TREE_VEC, in
3908 the form documented in cp-tree.h for template arguments. */
3910 static tree
3912 {
3913 tree header;
3918 /* If there is only one level of template parameters, we do not
3919 create a TREE_VEC of TREE_VECs. Instead, we return a single
3920 TREE_VEC containing the arguments. */
3925 {
3933 #ifdef ENABLE_CHECKING
3935 #endif
3939 else
3941 }
3944 /* This can happen for template parms of a template template
3945 parameter, e.g:
3947 template<template<class T, class U> class TT> struct S;
3949 Consider the level of the parms of TT; T and U both have
3950 level 2; TT has no template parm of level 1. So in this case
3951 the first element of full_template_args is NULL_TREE. If we
3952 leave it like this TMPL_ARGS_DEPTH on args returns 1 instead
3953 of 2. This will make tsubst wrongly consider that T and U
3954 have level 1. Instead, let's create a dummy vector as the
3955 first element of full_template_args so that TMPL_ARGS_DEPTH
3956 returns the correct depth for args. */
3959 }
3961 /* Within the declaration of a template, return the currently active
3962 template parameters as an argument TREE_VEC. */
3964 static tree
3966 {
3968 }
3970 /* Update the declared TYPE by doing any lookups which were thought to be
3971 dependent, but are not now that we know the SCOPE of the declarator. */
3973 tree
3975 {
3986 /* Don't bother building up the args in this case. */
3988 {
3989 /* tsubst in the args corresponding to the template parameters,
3990 including auto if present. Most things will be unchanged, but
3991 make_typename_type and tsubst_qualified_id will resolve
3992 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
3995 tree pushed;
3997 {
4001 }
4006 }
4012 {
4015 else
4017 }
4019 }
4021 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4022 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
4023 a member template. Used by push_template_decl below. */
4025 static tree
4027 {
4035 }
4037 struct template_parm_data
4038 {
4039 /* The level of the template parameters we are currently
4040 processing. */
4043 /* The index of the specialization argument we are currently
4044 processing. */
4047 /* An array whose size is the number of template parameters. The
4048 elements are nonzero if the parameter has been used in any one
4049 of the arguments processed so far. */
4052 /* An array whose size is the number of template arguments. The
4053 elements are nonzero if the argument makes use of template
4054 parameters of this level. */
4056 };
4058 /* Subroutine of push_template_decl used to see if each template
4059 parameter in a partial specialization is used in the explicit
4060 argument list. If T is of the LEVEL given in DATA (which is
4061 treated as a template_parm_data*), then DATA->PARMS is marked
4062 appropriately. */
4064 static int
4066 {
4074 {
4077 }
4079 /* Return zero so that for_each_template_parm will continue the
4080 traversal of the tree; we want to mark *every* template parm. */
4082 }
4084 /* Process the partial specialization DECL. */
4086 static tree
4088 {
4094 tree inner_parms;
4095 tree inst;
4108 /* We check that each of the template parameters given in the
4109 partial specialization is used in the argument list to the
4110 specialization. For example:
4112 template <class T> struct S;
4113 template <class T> struct S<T*>;
4115 The second declaration is OK because `T*' uses the template
4116 parameter T, whereas
4118 template <class T> struct S<int>;
4120 is no good. Even trickier is:
4122 template <class T>
4123 struct S1
4124 {
4125 template <class U>
4126 struct S2;
4127 template <class U>
4128 struct S2<T>;
4129 };
4131 The S2<T> declaration is actually invalid; it is a
4132 full-specialization. Of course,
4134 template <class U>
4135 struct S2<T (*)(U)>;
4137 or some such would have been OK. */
4145 {
4150 NULL,
4152 }
4155 {
4156 /* One of the template parms was not used in a deduced context in the
4157 specialization. */
4159 {
4163 }
4167 }
4172 /* [temp.class.spec]
4174 The argument list of the specialization shall not be identical to
4175 the implicit argument list of the primary template. */
4182 /* A partial specialization that replaces multiple parameters of the
4183 primary template with a pack expansion is less specialized for those
4184 parameters. */
4186 {
4188 "primary template because it replaces multiple parameters "
4192 }
4194 /* [temp.class.spec]
4196 A partially specialized non-type argument expression shall not
4197 involve template parameters of the partial specialization except
4198 when the argument expression is a simple identifier.
4200 The type of a template parameter corresponding to a specialized
4201 non-type argument shall not be dependent on a parameter of the
4202 specialization.
4204 Also, we verify that pack expansions only occur at the
4205 end of the argument list. */
4209 {
4216 {
4217 /* Extract the arguments from the argument pack. We'll be
4218 iterating over these in the following loop. */
4221 }
4224 {
4226 /* Get the Jth argument in the parameter pack. */
4230 {
4231 /* Pack expansions must come at the end of the
4232 argument list. */
4235 {
4239 else
4242 }
4243 }
4246 /* We only care about the pattern. */
4252 /* This next two lines are the `argument expression is not just a
4253 simple identifier' condition and also the `specialized
4254 non-type argument' bit. */
4258 {
4262 arg);
4263 else
4264 {
4265 /* Look at the corresponding template parameter,
4266 marking which template parameters its type depends
4267 upon. */
4271 {
4272 /* We haven't yet initialized TPD2. Do so now. */
4274 /* The number of parameters here is the number in the
4275 main template, which, as checked in the assertion
4276 above, is NARGS. */
4280 }
4282 /* Mark the template parameters. But this time, we're
4283 looking for the template parameters of the main
4284 template, not in the specialization. */
4291 NULL,
4295 {
4296 /* The type depended on some template parameters.
4297 If they are fully specialized in the
4298 specialization, that's OK. */
4307 "type %qT of template argument %qE depends "
4309 "type %qT of template argument %qE depends "
4311 type,
4312 arg);
4313 }
4314 }
4315 }
4316 }
4317 }
4319 /* We should only get here once. */
4337 {
4341 {
4345 "partial specialization of %qT after instantiation "
4347 }
4348 }
4351 }
4353 /* PARM is a template parameter of some form; return the corresponding
4354 TEMPLATE_PARM_INDEX. */
4356 static tree
4358 {
4370 }
4372 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4373 parameter packs used by the template parameter PARM. */
4375 static void
4377 {
4378 /* A type parm can't refer to another parm. */
4382 {
4386 }
4393 }
4395 /* PARM is a template parameter pack. Return any parameter packs used in
4396 its type or the type of any of its template parameters. If there are
4397 any such packs, it will be instantiated into a fixed template parameter
4398 list by partial instantiation rather than be fully deduced. */
4400 tree
4402 {
4403 /* This can only be true in a member template. */
4406 /* This can only be true for a parameter pack. */
4409 /* A type parm can't refer to another parm. */
4422 }
4424 /* Check that a template declaration's use of default arguments and
4425 parameter packs is not invalid. Here, PARMS are the template
4426 parameters. IS_PRIMARY is true if DECL is the thing declared by
4427 a primary template. IS_PARTIAL is true if DECL is a partial
4428 specialization.
4430 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4431 declaration (but not a definition); 1 indicates a declaration, 2
4432 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4433 emitted for extraneous default arguments.
4435 Returns TRUE if there were no errors found, FALSE otherwise. */
4437 bool
4440 {
4443 tree parm_level;
4446 /* [temp.param]
4448 A default template-argument shall not be specified in a
4449 function template declaration or a function template definition, nor
4450 in the template-parameter-list of the definition of a member of a
4451 class template. */
4455 /* You can't have a function template declaration in a local
4456 scope, nor you can you define a member of a class template in a
4457 local scope. */
4465 /* A lambda doesn't have an explicit declaration; don't complain
4466 about the parms of the enclosing class. */
4473 /* If this is either a friend defined in the scope of the class
4474 or a member function. */
4480 /* And, if it was a member function, it really was defined in
4481 the scope of the class. */
4484 /* We already checked these parameters when the template was
4485 declared, so there's no need to do it again now. This function
4486 was defined in class scope, but we're processing its body now
4487 that the class is complete. */
4490 /* Core issue 226 (C++0x only): the following only applies to class
4491 templates. */
4494 {
4495 /* [temp.param]
4497 If a template-parameter has a default template-argument, all
4498 subsequent template-parameters shall have a default
4499 template-argument supplied. */
4501 {
4508 {
4518 {
4520 /* For better subsequent error-recovery, we indicate that
4521 there should have been a default argument. */
4524 }
4526 && !is_friend_decl
4527 /* Don't complain about an enclosing partial
4528 specialization. */
4533 /* A fixed parameter pack will be partially
4534 instantiated into a fixed length list. */
4536 {
4537 /* A primary class template can only have one
4538 parameter pack, at the end of the template
4539 parameter list. */
4544 else
4552 }
4553 }
4554 }
4555 }
4558 || is_partial
4559 || !is_primary
4561 /* For an ordinary class template, default template arguments are
4562 allowed at the innermost level, e.g.:
4563 template <class T = int>
4564 struct S {};
4565 but, in a partial specialization, they're not allowed even
4566 there, as we have in [temp.class.spec]:
4568 The template parameter list of a specialization shall not
4569 contain default template argument values.
4571 So, for a partial specialization, or for a function template
4572 (in C++98/C++03), we look at all of them. */
4573 ;
4574 else
4575 /* But, for a primary class template that is not a partial
4576 specialization we look at all template parameters except the
4577 innermost ones. */
4580 /* Figure out what error message to issue. */
4593 else
4597 /* If we're inside a class definition, there's no need to
4598 examine the parameters to the class itself. On the one
4599 hand, they will be checked when the class is defined, and,
4600 on the other, default arguments are valid in things like:
4601 template <class T = double>
4602 struct S { template <class U> void f(U); };
4603 Here the default argument for `S' has no bearing on the
4604 declaration of `f'. */
4606 else
4607 /* Check everything. */
4613 {
4620 {
4625 {
4627 {
4634 }
4636 /* Clear out the default argument so that we are not
4637 confused later. */
4639 }
4640 }
4642 /* At this point, if we're still interested in issuing messages,
4643 they must apply to classes surrounding the object declared. */
4647 }
4650 }
4652 /* Worker for push_template_decl_real, called via
4653 for_each_template_parm. DATA is really an int, indicating the
4654 level of the parameters we are interested in. If T is a template
4655 parameter of that level, return nonzero. */
4657 static int
4659 {
4665 else
4668 }
4670 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
4671 parameters given by current_template_args, or reuses a
4672 previously existing one, if appropriate. Returns the DECL, or an
4673 equivalent one, if it is replaced via a call to duplicate_decls.
4675 If IS_FRIEND is true, DECL is a friend declaration. */
4677 tree
4679 {
4680 tree tmpl;
4681 tree args;
4682 tree info;
4683 tree ctx;
4687 /* True if the template is a member template, in the sense of
4688 [temp.mem]. */
4694 /* See if this is a partial specialization. */
4703 /* For a friend, we want the context of the friend function, not
4704 the type of which it is a friend. */
4708 /* In the case of a virtual function, we want the class in which
4709 it is defined. */
4711 else
4712 /* Otherwise, if we're currently defining some class, the DECL
4713 is assumed to be a member of the class. */
4722 /* See if this is a primary template. */
4725 /* A friend template that specifies a class context, i.e.
4726 template <typename T> friend void A<T>::f();
4727 is not primary. */
4732 else
4736 {
4741 {
4744 }
4746 {
4748 {
4751 }
4753 {
4754 /* [temp.mem]
4756 A destructor shall not be a member template. */
4759 }
4766 {
4767 /* [basic.stc.dynamic.allocation]
4769 An allocation function can be a function
4770 template. ... Template allocation functions shall
4771 have two or more parameters. */
4774 }
4775 }
4781 /* alias-declaration */
4785 else
4786 {
4789 }
4790 }
4792 /* Check to see that the rules regarding the use of default
4793 arguments are not being violated. */
4797 /* Ensure that there are no parameter packs in the type of this
4798 declaration that have not been expanded. */
4800 {
4801 /* Check each of the arguments individually to see if there are
4802 any bare parameter packs. */
4808 {
4811 {
4812 /* This is a PARM_DECL that contains unexpanded parameter
4813 packs. We have already complained about this in the
4814 check_for_bare_parameter_packs call, so just replace
4815 these types with ERROR_MARK_NODE. */
4818 }
4822 }
4824 /* Check for bare parameter packs in the return type and the
4825 exception specifiers. */
4827 /* Errors were already issued, set return type to int
4828 as the frontend doesn't expect error_mark_node as
4829 the return type. */
4833 }
4838 {
4841 }
4854 {
4859 /* If DECL is a TYPE_DECL for a class-template, then there won't
4860 be DECL_LANG_SPECIFIC. The information equivalent to
4861 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
4865 {
4866 /* Since a template declaration already existed for this
4867 class-type, we must be redeclaring it here. Make sure
4868 that the redeclaration is valid. */
4870 current_template_parms);
4871 /* We don't need to create a new TEMPLATE_DECL; just use the
4872 one we already had. */
4874 }
4875 else
4876 {
4878 member_template_p);
4883 {
4884 /* A specialization of a member template of a template
4885 class. */
4889 }
4890 }
4891 }
4892 else
4893 {
4899 {
4902 }
4910 {
4911 tree new_tmpl;
4913 /* The declaration is a specialization of a member
4914 template, declared outside the class. Therefore, the
4915 innermost template arguments will be NULL, so we
4916 replace them with the arguments determined by the
4917 earlier call to check_explicit_specialization. */
4920 new_tmpl
4922 member_template_p);
4932 args,
4935 }
4937 /* Make sure the template headers we got make sense. */
4942 {
4947 }
4948 else
4950 {
4955 {
4959 else
4963 /* Avoid crash in import_export_decl. */
4966 }
4971 /* Can happen in erroneous input. */
4973 else
4975 }
4977 /* Check that the parms are used in the appropriate qualifying scopes
4978 in the declarator. */
4982 {
4988 /* Avoid crash in import_export_decl. */
4991 }
4992 }
4997 /* Push template declarations for global functions and types. Note
4998 that we do not try to push a global template friend declared in a
4999 template class; such a thing may well depend on the template
5000 parameters of the class. */
5003 {
5008 /* Hide template friend classes that haven't been declared yet. */
5010 {
5013 }
5014 }
5017 {
5023 {
5026 /* It is a conversion operator. See if the type converted to
5027 depends on innermost template operands. */
5030 depth))
5032 }
5034 /* Give template template parms a DECL_CONTEXT of the template
5035 for which they are a parameter. */
5038 {
5042 }
5043 }
5045 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5046 back to its most general template. If TMPL is a specialization,
5047 ARGS may only have the innermost set of arguments. Add the missing
5048 argument levels if necessary. */
5056 else
5057 {
5062 }
5065 && !is_friend
5068 /* Set DECL_COMDAT on template instantiations; if we force
5069 them to be emitted by explicit instantiation or -frepo,
5070 mark_needed will tell cgraph to do the right thing. */
5074 }
5076 tree
5078 {
5080 }
5082 /* FN is an inheriting constructor that inherits from the constructor
5083 template INHERITED; turn FN into a constructor template with a matching
5084 template header. */
5086 tree
5088 {
5089 tree inner_parms
5092 tree parms
5103 }
5105 /* Called when a class template TYPE is redeclared with the indicated
5106 template PARMS, e.g.:
5108 template <class T> struct S;
5109 template <class T> struct S {}; */
5111 bool
5113 {
5114 tree tmpl;
5115 tree tmpl_parms;
5119 {
5122 }
5126 /* The type is nested in some template class. Nothing to worry
5127 about here; there are no new template parameters for the nested
5128 type. */
5132 {
5134 tmpl);
5136 }
5142 {
5152 }
5155 {
5156 tree tmpl_parm;
5157 tree parm;
5158 tree tmpl_default;
5159 tree parm_default;
5173 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5174 TEMPLATE_DECL. */
5184 {
5188 }
5191 {
5192 /* We have in [temp.param]:
5194 A template-parameter may not be given default arguments
5195 by two different declarations in the same scope. */
5200 }
5203 /* Update the previous template parameters (which are the ones
5204 that will really count) with the new default value. */
5207 /* Update the new parameters, too; they'll be used as the
5208 parameters for any members. */
5210 }
5213 }
5215 /* Simplify EXPR if it is a non-dependent expression. Returns the
5216 (possibly simplified) expression. */
5218 tree
5220 {
5224 /* If we're in a template, but EXPR isn't value dependent, simplify
5225 it. We're supposed to treat:
5227 template <typename T> void f(T[1 + 1]);
5228 template <typename T> void f(T[2]);
5230 as two declarations of the same function, for example. */
5234 {
5235 HOST_WIDE_INT saved_processing_template_decl;
5241 complain,
5246 }
5248 }
5250 tree
5252 {
5254 }
5256 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5257 template declaration, or a TYPE_DECL for an alias declaration. */
5259 bool
5261 {
5269 }
5271 /* Return TRUE iff is a specialization of an alias template. */
5273 bool
5275 {
5283 }
5285 /* Return the number of innermost template parameters in TMPL. */
5287 static int
5289 {
5292 }
5294 /* Return either TMPL or another template that it is equivalent to under DR
5295 1286: An alias that just changes the name of a template is equivalent to
5296 the other template. */
5298 static tree
5300 {
5303 {
5306 {
5311 {
5312 tree alias_args = INNERMOST_TEMPLATE_ARGS
5316 /* The alias type is equivalent to the pattern of the
5317 underlying template, so strip the alias. */
5320 }
5321 }
5323 }
5325 }
5327 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5328 must be a function or a pointer-to-function type, as specified
5329 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5330 and check that the resulting function has external linkage. */
5332 static tree
5334 tsubst_flags_t complain)
5335 {
5338 linkage_kind linkage;
5350 /* [temp.arg.nontype]/1
5352 A template-argument for a non-type, non-template template-parameter
5353 shall be one of:
5354 [...]
5355 -- the address of an object or function with external [C++11: or
5356 internal] linkage. */
5359 {
5361 {
5367 else
5370 }
5372 }
5376 {
5378 {
5383 else
5387 }
5389 }
5392 }
5394 /* Subroutine of convert_nontype_argument.
5395 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5396 Emit an error otherwise. */
5398 static bool
5400 tsubst_flags_t complain)
5401 {
5412 {
5416 }
5418 }
5420 /* Returns TRUE iff the address of OP is value-dependent.
5422 14.6.2.4 [temp.dep.temp]:
5423 A non-integral non-type template-argument is dependent if its type is
5424 dependent or it has either of the following forms
5425 qualified-id
5426 & qualified-id
5427 and contains a nested-name-specifier which specifies a class-name that
5428 names a dependent type.
5430 We generalize this to just say that the address of a member of a
5431 dependent class is value-dependent; the above doesn't cover the
5432 address of a static data member named with an unqualified-id. */
5434 static bool
5436 {
5437 /* We could use get_inner_reference here, but there's no need;
5438 this is only relevant for template non-type arguments, which
5439 can only be expressed as &id-expression. */
5441 {
5445 }
5448 }
5450 /* The next set of functions are used for providing helpful explanatory
5451 diagnostics for failed overload resolution. Their messages should be
5452 indented by two spaces for consistency with the messages in
5453 call.c */
5455 static int
5457 {
5459 }
5461 static int
5463 {
5468 }
5470 static int
5472 {
5474 }
5476 static int
5478 {
5484 }
5486 static int
5488 {
5492 }
5494 static int
5496 {
5499 " template parameter %qD is not a parameter pack, but "
5503 }
5505 static int
5507 {
5510 " template argument %qE does not match "
5514 }
5516 static int
5518 {
5522 }
5524 static int
5526 {
5532 }
5534 static int
5536 {
5538 {
5543 else
5545 " deduced conflicting values for non-type parameter "
5547 }
5549 }
5551 static int
5553 {
5556 " variable-sized array type %qT is not "
5558 arg);
5560 }
5562 static int
5564 {
5568 arg);
5570 }
5572 static int
5574 {
5576 {
5582 else
5587 }
5589 }
5591 static int
5593 {
5595 }
5597 static int
5600 {
5602 }
5604 static int
5607 {
5613 }
5615 static int
5618 {
5621 {
5629 }
5631 }
5633 static int
5635 {
5638 " template parameters of a template template argument are "
5641 }
5643 static int
5645 {
5651 }
5653 static int
5655 {
5660 }
5662 static int
5664 {
5668 arg);
5670 }
5672 /* Attempt to convert the non-type template parameter EXPR to the
5673 indicated TYPE. If the conversion is successful, return the
5674 converted value. If the conversion is unsuccessful, return
5675 NULL_TREE if we issued an error message, or error_mark_node if we
5676 did not. We issue error messages for out-and-out bad template
5677 parameters, but not simply because the conversion failed, since we
5678 might be just trying to do argument deduction. Both TYPE and EXPR
5679 must be non-dependent.
5681 The conversion follows the special rules described in
5682 [temp.arg.nontype], and it is much more strict than an implicit
5683 conversion.
5685 This function is called twice for each template argument (see
5686 lookup_template_class for a more accurate description of this
5687 problem). This means that we need to handle expressions which
5688 are not valid in a C++ source, but can be created from the
5689 first call (for instance, casts to perform conversions). These
5690 hacks can go away after we fix the double coercion problem. */
5692 static tree
5694 {
5695 tree expr_type;
5697 /* Detect immediately string literals as invalid non-type argument.
5698 This special-case is not needed for correctness (we would easily
5699 catch this later), but only to provide better diagnostic for this
5700 common user mistake. As suggested by DR 100, we do not mention
5701 linkage issues in the diagnostic as this is not the point. */
5702 /* FIXME we're making this OK. */
5704 {
5710 }
5712 /* Add the ADDR_EXPR now for the benefit of
5713 value_dependent_expression_p. */
5716 {
5720 }
5722 /* If we are in a template, EXPR may be non-dependent, but still
5723 have a syntactic, rather than semantic, form. For example, EXPR
5724 might be a SCOPE_REF, rather than the VAR_DECL to which the
5725 SCOPE_REF refers. Preserving the qualifying scope is necessary
5726 so that access checking can be performed when the template is
5727 instantiated -- but here we need the resolved form so that we can
5728 convert the argument. */
5739 else
5742 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
5743 to a non-type argument of "nullptr". */
5747 /* In C++11, integral or enumeration non-type template arguments can be
5748 arbitrary constant expressions. Pointer and pointer to
5749 member arguments can be general constant expressions that evaluate
5750 to a null value, but otherwise still need to be of a specific form. */
5752 {
5754 /* A PTRMEM_CST is already constant, and a valid template
5755 argument for a parameter of pointer to member type, we just want
5756 to leave it in that form rather than lower it to a
5761 {
5766 }
5767 }
5769 /* HACK: Due to double coercion, we can get a
5770 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5771 which is the tree that we built on the first call (see
5772 below when coercing to reference to object or to reference to
5773 function). We just strip everything and get to the arg.
5774 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5775 for examples. */
5777 {
5783 {
5784 /* ??? Maybe we could use convert_from_reference here, but we
5785 would need to relax its constraints because the NOP_EXPR
5786 could actually change the type to something more cv-qualified,
5787 and this is not folded by convert_from_reference. */
5792 && (same_type_ignoring_top_level_qualifiers_p
5795 {
5798 }
5799 }
5800 }
5802 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5803 parameter is a pointer to object, through decay and
5804 qualification conversion. Let's strip everything. */
5806 {
5811 {
5812 /* Skip the ADDR_EXPR only if it is part of the decay for
5813 an array. Otherwise, it is part of the original argument
5814 in the source code. */
5819 }
5820 }
5822 /* [temp.arg.nontype]/5, bullet 1
5824 For a non-type template-parameter of integral or enumeration type,
5825 integral promotions (_conv.prom_) and integral conversions
5826 (_conv.integral_) are applied. */
5828 {
5837 /* Notice that there are constant expressions like '4 % 0' which
5838 do not fold into integer constants. */
5840 {
5842 {
5853 /* else cxx_constant_value complained but gave us
5854 a real constant, so go ahead. */
5856 }
5857 else
5859 }
5861 /* Avoid typedef problems. */
5864 }
5865 /* [temp.arg.nontype]/5, bullet 2
5867 For a non-type template-parameter of type pointer to object,
5868 qualification conversions (_conv.qual_) and the array-to-pointer
5869 conversion (_conv.array_) are applied. */
5871 {
5872 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
5874 A template-argument for a non-type, non-template template-parameter
5875 shall be one of: [...]
5877 -- the name of a non-type template-parameter;
5878 -- the address of an object or function with external linkage, [...]
5879 expressed as "& id-expression" where the & is optional if the name
5880 refers to a function or array, or if the corresponding
5881 template-parameter is a reference.
5883 Here, we do not care about functions, as they are invalid anyway
5884 for a parameter of type pointer-to-object. */
5887 /* Non-type template parameters are OK. */
5888 ;
5893 {
5895 {
5898 "because %qD is a variable, not the address of "
5901 }
5903 {
5909 }
5910 /* Other values, like integer constants, might be valid
5911 non-type arguments of some other type. */
5913 }
5914 else
5915 {
5916 tree decl;
5921 {
5926 }
5928 {
5934 }
5936 {
5941 }
5942 }
5951 }
5952 /* [temp.arg.nontype]/5, bullet 3
5954 For a non-type template-parameter of type reference to object, no
5955 conversions apply. The type referred to by the reference may be more
5956 cv-qualified than the (otherwise identical) type of the
5957 template-argument. The template-parameter is bound directly to the
5958 template-argument, which must be an lvalue. */
5960 {
5962 expr_type))
5966 {
5971 }
5974 {
5979 }
5981 /* [temp.arg.nontype]/1
5983 A template-argument for a non-type, non-template template-parameter
5984 shall be one of: [...]
5986 -- the address of an object or function with external linkage. */
5989 {
5992 {
5995 "because a reference variable does not have a constant "
5998 }
5999 }
6002 {
6008 }
6011 {
6017 }
6020 }
6021 /* [temp.arg.nontype]/5, bullet 4
6023 For a non-type template-parameter of type pointer to function, only
6024 the function-to-pointer conversion (_conv.func_) is applied. If the
6025 template-argument represents a set of overloaded functions (or a
6026 pointer to such), the matching function is selected from the set
6027 (_over.over_). */
6029 {
6030 /* If the argument is a template-id, we might not have enough
6031 context information to decay the pointer. */
6033 {
6037 }
6040 /* Null pointer values are OK in C++11. */
6046 }
6047 /* [temp.arg.nontype]/5, bullet 5
6049 For a non-type template-parameter of type reference to function, no
6050 conversions apply. If the template-argument represents a set of
6051 overloaded functions, the matching function is selected from the set
6052 (_over.over_). */
6054 {
6056 {
6058 {
6063 }
6065 }
6072 }
6073 /* [temp.arg.nontype]/5, bullet 6
6075 For a non-type template-parameter of type pointer to member function,
6076 no conversions apply. If the template-argument represents a set of
6077 overloaded member functions, the matching member function is selected
6078 from the set (_over.over_). */
6080 {
6085 /* [temp.arg.nontype] bullet 1 says the pointer to member
6086 expression must be a pointer-to-member constant. */
6090 /* There is no way to disable standard conversions in
6091 resolve_address_of_overloaded_function (called by
6092 instantiate_type). It is possible that the call succeeded by
6093 converting &B::I to &D::I (where B is a base of D), so we need
6094 to reject this conversion here.
6096 Actually, even if there was a way to disable standard conversions,
6097 it would still be better to reject them here so that we can
6098 provide a superior diagnostic. */
6100 {
6102 {
6106 /* If we are just one standard conversion off, explain. */
6110 }
6112 }
6113 }
6114 /* [temp.arg.nontype]/5, bullet 7
6116 For a non-type template-parameter of type pointer to data member,
6117 qualification conversions (_conv.qual_) are applied. */
6119 {
6120 /* [temp.arg.nontype] bullet 1 says the pointer to member
6121 expression must be a pointer-to-member constant. */
6128 }
6130 {
6132 {
6137 }
6139 }
6140 /* A template non-type parameter must be one of the above. */
6141 else
6144 /* Sanity check: did we actually convert the argument to the
6145 right type? */
6149 }
6151 /* Subroutine of coerce_template_template_parms, which returns 1 if
6152 PARM_PARM and ARG_PARM match using the rule for the template
6153 parameters of template template parameters. Both PARM and ARG are
6154 template parameters; the rest of the arguments are the same as for
6155 coerce_template_template_parms.
6156 */
6157 static int
6159 tree arg,
6160 tsubst_flags_t complain,
6161 tree in_decl,
6162 tree outer_args)
6163 {
6172 {
6174 /* We encounter instantiations of templates like
6175 template <template <template <class> class> class TT>
6176 class C; */
6177 {
6184 }
6185 /* Fall through. */
6190 /* Argument is a parameter pack but parameter is not. */
6195 /* The tsubst call is used to handle cases such as
6197 template <int> class C {};
6198 template <class T, template <T> class TT> class D {};
6199 D<int, C> d;
6201 i.e. the parameter list of TT depends on earlier parameters. */
6203 && !same_type_p
6210 /* Argument is a parameter pack but parameter is not. */
6217 }
6220 }
6223 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6224 template template parameters. Both PARM_PARMS and ARG_PARMS are
6225 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6226 or PARM_DECL.
6228 Consider the example:
6229 template <class T> class A;
6230 template<template <class U> class TT> class B;
6232 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6233 the parameters to A, and OUTER_ARGS contains A. */
6235 static int
6237 tree arg_parms,
6238 tsubst_flags_t complain,
6239 tree in_decl,
6240 tree outer_args)
6241 {
6252 /* Determine whether we have a parameter pack at the end of the
6253 template template parameter's template parameter list. */
6255 {
6262 {
6276 }
6277 }
6283 /* Check all of the template parameters except the parameter pack at
6284 the end (if any). */
6286 {
6295 outer_args))
6298 }
6301 {
6302 /* Check each of the template parameters in the template
6303 argument against the template parameter pack at the end of
6304 the template template parameter. */
6311 {
6318 outer_args))
6320 }
6321 }
6324 }
6326 /* Verifies that the deduced template arguments (in TARGS) for the
6327 template template parameters (in TPARMS) represent valid bindings,
6328 by comparing the template parameter list of each template argument
6329 to the template parameter list of its corresponding template
6330 template parameter, in accordance with DR150. This
6331 routine can only be called after all template arguments have been
6332 deduced. It will return TRUE if all of the template template
6333 parameter bindings are okay, FALSE otherwise. */
6334 bool
6336 {
6340 /* We're dealing with template parms in this process. */
6346 {
6351 {
6356 {
6357 /* Look inside the argument pack. */
6360 }
6363 {
6367 /* Extract the next argument from the argument
6368 pack. */
6372 /* Look at the pattern of the pack expansion. */
6375 /* Extract the template parameters from the template
6376 argument. */
6382 /* Verify that we can coerce the template template
6383 parameters from the template argument to the template
6384 parameter. This requires an exact match. */
6386 && !coerce_template_template_parms
6388 targ_parms,
6389 tf_none,
6390 tparm,
6391 targs))
6392 {
6395 }
6396 }
6397 }
6398 }
6400 out:
6404 }
6406 /* Since type attributes aren't mangled, we need to strip them from
6407 template type arguments. */
6409 static tree
6411 {
6412 tree mv;
6419 {
6424 }
6426 }
6428 /* Convert the indicated template ARG as necessary to match the
6429 indicated template PARM. Returns the converted ARG, or
6430 error_mark_node if the conversion was unsuccessful. Error and
6431 warning messages are issued under control of COMPLAIN. This
6432 conversion is for the Ith parameter in the parameter list. ARGS is
6433 the full set of template arguments deduced so far. */
6435 static tree
6437 tree arg,
6438 tree args,
6439 tsubst_flags_t complain,
6441 tree in_decl)
6442 {
6443 tree orig_arg;
6444 tree val;
6449 {
6450 /* The template argument was the name of some
6451 member function. That's usually
6452 invalid, but static members are OK. In any
6453 case, grab the underlying fields/functions
6454 and issue an error later if required. */
6457 }
6465 /* When determining whether an argument pack expansion is a template,
6466 look at the pattern. */
6470 /* Deal with an injected-class-name used as a template template arg. */
6472 {
6475 {
6485 }
6486 }
6488 is_tmpl_type =
6504 {
6506 {
6510 }
6513 "to refer to a type member of a template parameter, "
6518 typename_type,
6519 complain);
6522 }
6524 {
6526 {
6528 {
6540 else
6543 }
6544 }
6546 }
6548 {
6550 {
6557 else
6560 }
6562 }
6565 {
6567 {
6571 /* The number of argument required is not known yet.
6572 Just accept it for now. */
6574 else
6575 {
6577 tree argparm;
6579 /* Strip alias templates that are equivalent to another
6580 template. */
6586 args))
6587 {
6590 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6591 TEMPLATE_DECL. */
6593 {
6598 }
6599 }
6600 else
6601 {
6603 {
6610 }
6613 }
6614 }
6615 }
6616 else
6618 /* We only form one instance of each template specialization.
6619 Therefore, if we use a non-canonical variant (i.e., a
6620 typedef), any future messages referring to the type will use
6621 the typedef, which is confusing if those future uses do not
6622 themselves also use the typedef. */
6625 }
6626 else
6627 {
6634 {
6637 else
6638 {
6639 /* Not sure if this is reachable, but it doesn't hurt
6640 to be robust. */
6643 }
6644 }
6647 /* We used to call digest_init here. However, digest_init
6648 will report errors, which we don't want when complain
6649 is zero. More importantly, digest_init will try too
6650 hard to convert things: for example, `0' should not be
6651 converted to pointer type at this point according to
6652 the standard. Accepting this is not merely an
6653 extension, since deciding whether or not these
6654 conversions can occur is part of determining which
6655 function template to call, or whether a given explicit
6656 argument specification is valid. */
6658 else
6667 {
6668 /* Strip typedefs from the SCOPE_REF. */
6671 complain);
6674 }
6675 }
6678 }
6680 /* Coerces the remaining template arguments in INNER_ARGS (from
6681 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6682 Returns the coerced argument pack. PARM_IDX is the position of this
6683 parameter in the template parameter list. ARGS is the original
6684 template argument list. */
6685 static tree
6688 tree args,
6689 tree inner_args,
6691 tree new_args,
6693 tree in_decl,
6694 tsubst_flags_t complain)
6695 {
6698 tree packed_args;
6699 tree argument_pack;
6706 {
6707 /* When the template parameter is a non-type template parameter pack
6708 or template template parameter pack whose type or template
6709 parameters use parameter packs, we know exactly how many arguments
6710 we are looking for. Build a vector of the instantiated decls for
6711 these template parameters in PACKED_PARMS. */
6712 /* We can't use make_pack_expansion here because it would interpret a
6713 _DECL as a use rather than a declaration. */
6727 /* If we're doing a partial instantiation of a member template,
6728 verify that all of the types used for the non-type
6729 template parameter pack are, in fact, valid for non-type
6730 template parameters. */
6733 {
6736 {
6740 }
6741 }
6744 }
6745 else
6748 /* Convert the remaining arguments, which will be a part of the
6749 parameter pack "parm". */
6751 {
6757 {
6758 /* Once we've packed as many args as we have types, stop. */
6762 /* We don't know how many args we have yet, just
6763 use the unconverted ones for now. */
6765 else
6767 }
6770 {
6773 }
6774 else
6777 in_decl);
6781 }
6785 {
6790 }
6795 else
6796 {
6801 }
6804 #ifdef ENABLE_CHECKING
6807 #endif
6809 }
6811 /* Returns the number of pack expansions in the template argument vector
6812 ARGS. */
6814 static int
6816 {
6821 {
6825 }
6827 }
6829 /* Convert all template arguments to their appropriate types, and
6830 return a vector containing the innermost resulting template
6831 arguments. If any error occurs, return error_mark_node. Error and
6832 warning messages are issued under control of COMPLAIN.
6834 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6835 for arguments not specified in ARGS. Otherwise, if
6836 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
6837 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
6838 USE_DEFAULT_ARGS is false, then all arguments must be specified in
6839 ARGS. */
6841 static tree
6843 tree args,
6844 tree in_decl,
6845 tsubst_flags_t complain,
6848 {
6850 tree orig_inner_args;
6851 tree inner_args;
6852 tree new_args;
6853 tree new_inner_args;
6857 /* When used as a boolean value, indicates whether this is a
6858 variadic template parameter list. Since it's an int, we can also
6859 subtract it from nparms to get the number of non-variadic
6860 parameters. */
6865 /* Likewise for parameters with default arguments. */
6873 /* Determine if there are any parameter packs or default arguments. */
6875 {
6883 }
6886 /* If there are no parameters that follow a parameter pack, we need to
6887 expand any argument packs so that we can deduce a parameter pack from
6888 some non-packed args followed by an argument pack, as in variadic85.C.
6889 If there are such parameters, we need to leave argument packs intact
6890 so the arguments are assigned properly. This can happen when dealing
6891 with a nested class inside a partial specialization of a class
6892 template, as in variadic92.C, or when deducing a template parameter pack
6893 from a sub-declarator, as in variadic114.C. */
6897 /* Count any pack expansion args. */
6903 && require_all_args
6904 && !variadic_args_p
6905 && (!use_default_args
6908 {
6910 {
6912 {
6916 }
6917 else
6923 }
6926 }
6927 /* We can't pass a pack expansion to a non-pack parameter of an alias
6928 template (DR 1430). */
6930 && variadic_args_p
6932 {
6934 {
6936 {
6942 {
6947 }
6948 }
6950 found:;
6951 }
6953 }
6955 /* We need to evaluate the template arguments, even though this
6956 template-id may be nested within a "sizeof". */
6965 {
6966 tree arg;
6967 tree parm;
6969 /* Get the Ith template parameter. */
6973 {
6976 }
6978 /* Calculate the next argument. */
6981 else
6986 {
6987 /* Some arguments will be placed in the
6988 template parameter pack PARM. */
6995 {
6996 /* We don't know how many args we have yet, just use the
6997 unconverted (and still packed) ones for now. */
7001 }
7005 /* Store this argument. */
7007 {
7008 lost++;
7009 /* We are done with all of the arguments. */
7011 }
7012 else
7013 {
7016 }
7019 }
7021 {
7023 {
7024 /* "If every valid specialization of a variadic template
7025 requires an empty template parameter pack, the template is
7026 ill-formed, no diagnostic required." So check that the
7027 pattern works with this parameter. */
7032 in_decl);
7034 {
7038 }
7040 /* Recover from missing typename. */
7044 /* We don't know how many args we have yet, just
7045 use the unconverted ones for now. */
7049 }
7050 }
7052 {
7053 /* There must be a default arg in this case. */
7056 /* The position of the first default template argument,
7057 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
7058 Record that. */
7062 }
7063 else
7067 {
7070 }
7072 /* This only occurs if there was an error in the template
7073 parameter list itself (which we would already have
7074 reported) that we are trying to recover from, e.g., a class
7075 template with a parameter list such as
7076 template<typename..., typename>. */
7078 else
7084 lost++;
7086 }
7091 {
7093 {
7098 }
7100 }
7105 #ifdef ENABLE_CHECKING
7109 #endif
7112 }
7114 /* Like coerce_template_parms. If PARMS represents all template
7115 parameters levels, this function returns a vector of vectors
7116 representing all the resulting argument levels. Note that in this
7117 case, only the innermost arguments are coerced because the
7118 outermost ones are supposed to have been coerced already.
7120 Otherwise, if PARMS represents only (the innermost) vector of
7121 parameters, this function returns a vector containing just the
7122 innermost resulting arguments. */
7124 static tree
7126 tree args,
7127 tree in_decl,
7128 tsubst_flags_t complain,
7131 {
7134 tree coerced_args;
7137 {
7139 tree level;
7145 {
7146 tree l;
7150 require_all_args,
7151 use_default_args);
7152 else
7159 }
7160 }
7161 else
7164 require_all_args,
7165 use_default_args);
7167 }
7169 /* Returns 1 if template args OT and NT are equivalent. */
7171 static int
7173 {
7180 /* For member templates */
7189 {
7206 }
7208 {
7209 /* We get here probably because we are in the middle of substituting
7210 into the pattern of a pack expansion. In that case the
7211 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
7212 interested in. So we want to use the initial pack argument for
7213 the comparison. */
7218 }
7223 else
7225 }
7227 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
7228 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
7229 NEWARG_PTR with the offending arguments if they are non-NULL. */
7231 static int
7234 {
7247 {
7252 {
7258 }
7259 }
7261 }
7263 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
7264 of template arguments. Returns 0 otherwise. */
7266 int
7268 {
7270 }
7272 static void
7274 {
7284 /* We are called both from instantiate_decl, where we've already had a
7285 tinst_level pushed, and instantiate_template, where we haven't.
7286 Compensate. */
7297 else
7306 }
7309 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
7310 ARGLIST. Valid choices for FNS are given in the cp-tree.def
7311 documentation for TEMPLATE_ID_EXPR. */
7313 tree
7315 {
7316 tree type;
7324 {
7327 }
7330 {
7332 unknown_type_node,
7334 arglist);
7336 }
7343 }
7345 /* Within the scope of a template class S<T>, the name S gets bound
7346 (in build_self_reference) to a TYPE_DECL for the class, not a
7347 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
7348 or one of its enclosing classes, and that type is a template,
7349 return the associated TEMPLATE_DECL. Otherwise, the original
7350 DECL is returned.
7352 Also handle the case when DECL is a TREE_LIST of ambiguous
7353 injected-class-names from different bases. */
7355 tree
7357 {
7361 /* DR 176: A lookup that finds an injected-class-name (10.2
7362 [class.member.lookup]) can result in an ambiguity in certain cases
7363 (for example, if it is found in more than one base class). If all of
7364 the injected-class-names that are found refer to specializations of
7365 the same class template, and if the name is followed by a
7366 template-argument-list, the reference refers to the class template
7367 itself and not a specialization thereof, and is not ambiguous. */
7369 {
7372 {
7378 }
7381 else
7383 }
7389 }
7391 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
7392 parameters, find the desired type.
7394 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
7396 IN_DECL, if non-NULL, is the template declaration we are trying to
7397 instantiate.
7399 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
7400 the class we are looking up.
7402 Issue error and warning messages under control of COMPLAIN.
7404 If the template class is really a local class in a template
7405 function, then the FUNCTION_CONTEXT is the function in which it is
7406 being instantiated.
7408 ??? Note that this function is currently called *twice* for each
7409 template-id: the first time from the parser, while creating the
7410 incomplete type (finish_template_type), and the second type during the
7411 real instantiation (instantiate_template_class). This is surely something
7412 that we want to avoid. It also causes some problems with argument
7413 coercion (see convert_nontype_argument for more information on this). */
7415 static tree
7418 {
7420 tree t;
7423 spec_entry elt;
7424 hashval_t hash;
7427 {
7431 else
7432 {
7439 }
7442 }
7444 {
7447 /* If we are declaring a constructor, say A<T>::A<T>, we will get
7448 an implicit typename for the second A. Deal with it. */
7453 {
7456 }
7457 }
7460 {
7463 }
7465 {
7469 }
7471 {
7474 }
7476 /* Issue an error message if we didn't find a template. */
7478 {
7482 }
7485 /* Make sure it's a user visible template, if it was named by
7486 the user. */
7489 {
7491 {
7495 }
7497 }
7501 /* An alias that just changes the name of a template is equivalent to the
7502 other template, so if any of the arguments are pack expansions, strip
7503 the alias to avoid problems with a pack expansion passed to a non-pack
7504 alias template parameter (DR 1430). */
7509 {
7510 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7511 template arguments */
7513 tree parm;
7514 tree arglist2;
7515 tree outer;
7519 /* Consider an example where a template template parameter declared as
7521 template <class T, class U = std::allocator<T> > class TT
7523 The template parameter level of T and U are one level larger than
7524 of TT. To proper process the default argument of U, say when an
7525 instantiation `TT<int>' is seen, we need to build the full
7526 arguments containing {int} as the innermost level. Outer levels,
7527 available when not appearing as default template argument, can be
7528 obtained from the arguments of the enclosing template.
7530 Suppose that TT is later substituted with std::vector. The above
7531 instantiation is `TT<int, std::allocator<T> >' with TT at
7532 level 1, and T at level 2, while the template arguments at level 1
7533 becomes {std::vector} and the inner level 2 is {int}. */
7539 /* This is an argument of the current template, so we haven't set
7540 DECL_CONTEXT yet. */
7547 complain,
7557 }
7558 else
7559 {
7561 tree gen_tmpl;
7562 tree type_decl;
7570 /* An error occurred while building the template TEMPL, and a
7571 diagnostic has most certainly been emitted for that
7572 already. Let's propagate that error. */
7581 {
7582 /* We've been given an incomplete set of template arguments.
7583 For example, given:
7585 template <class T> struct S1 {
7586 template <class U> struct S2 {};
7587 template <class U> struct S2<U*> {};
7588 };
7590 we will be called with an ARGLIST of `U*', but the
7591 TEMPLATE will be `template <class T> template
7592 <class U> struct S1<T>::S2'. We must fill in the missing
7593 arguments. */
7594 arglist
7596 arglist);
7598 }
7600 /* Now we should have enough arguments. */
7603 /* From here on, we're only interested in the most general
7604 template. */
7606 /* Calculate the BOUND_ARGS. These will be the args that are
7607 actually tsubst'd into the definition to create the
7608 instantiation. */
7610 {
7611 /* We have multiple levels of arguments to coerce, at once. */
7621 {
7622 tree a;
7626 complain,
7629 else
7630 /* Outer levels should have already been coerced. */
7633 /* Don't process further if one of the levels fails. */
7635 {
7636 /* Restore the ARGLIST to its full size. */
7639 }
7643 /* We temporarily reduce the length of the ARGLIST so
7644 that coerce_template_parms will see only the arguments
7645 corresponding to the template parameters it is
7646 examining. */
7648 }
7650 /* Restore the ARGLIST to its full size. */
7654 }
7655 else
7656 arglist
7659 gen_tmpl,
7660 complain,
7665 /* We were unable to bind the arguments. */
7668 /* In the scope of a template class, explicit references to the
7669 template class refer to the type of the template, not any
7670 instantiation of it. For example, in:
7672 template <class T> class C { void f(C<T>); }
7674 the `C<T>' is just the same as `C'. Outside of the
7675 class, however, such a reference is an instantiation. */
7679 /* comp_template_args is expensive, check it last. */
7681 arglist))
7684 /* If we already have this specialization, return it. */
7695 /* If the deduced arguments are invalid, then the binding
7696 failed. */
7700 complain))
7707 {
7712 }
7722 /* Create the type. */
7724 {
7725 /* The user referred to a specialization of an alias
7726 template represented by GEN_TMPL.
7728 [temp.alias]/2 says:
7730 When a template-id refers to the specialization of an
7731 alias template, it is equivalent to the associated
7732 type obtained by substitution of its
7733 template-arguments for the template-parameters in the
7734 type-id of the alias template. */
7737 /* Note that the call above (by indirectly calling
7738 register_specialization in tsubst_decl) registers the
7739 TYPE_DECL representing the specialization of the alias
7740 template. So next time someone substitutes ARGLIST for
7741 the template parms into the alias template (GEN_TMPL),
7742 she'll get that TYPE_DECL back. */
7746 }
7748 {
7750 {
7759 }
7760 else
7761 {
7762 /* We don't want to call start_enum for this type, since
7763 the values for the enumeration constants may involve
7764 template parameters. And, no one should be interested
7765 in the enumeration constants for such a type. */
7768 }
7772 }
7774 {
7781 /* A local class. Make sure the decl gets registered properly. */
7786 /* This instantiation is another name for the primary
7787 template type. Set the TYPE_CANONICAL field
7788 appropriately. */
7791 /* Some of the template arguments require structural
7792 equality testing, so this template class requires
7793 structural equality testing. */
7795 }
7796 else
7799 /* If we called start_enum or pushtag above, this information
7800 will already be set up. */
7802 {
7809 }
7810 else
7814 {
7820 {
7823 }
7824 }
7828 {
7831 {
7834 else
7838 }
7839 }
7841 /* Let's consider the explicit specialization of a member
7842 of a class template specialization that is implicitly instantiated,
7843 e.g.:
7844 template<class T>
7845 struct S
7846 {
7847 template<class U> struct M {}; //#0
7848 };
7850 template<>
7851 template<>
7852 struct S<int>::M<char> //#1
7853 {
7854 int i;
7855 };
7856 [temp.expl.spec]/4 says this is valid.
7858 In this case, when we write:
7859 S<int>::M<char> m;
7861 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
7862 the one of #0.
7864 When we encounter #1, we want to store the partial instantiation
7865 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
7867 For all cases other than this "explicit specialization of member of a
7868 class template", we just want to store the most general template into
7869 the CLASSTYPE_TI_TEMPLATE of M.
7871 This case of "explicit specialization of member of a class template"
7872 only happens when:
7873 1/ the enclosing class is an instantiation of, and therefore not
7874 the same as, the context of the most general template, and
7875 2/ we aren't looking at the partial instantiation itself, i.e.
7876 the innermost arguments are not the same as the innermost parms of
7877 the most general template.
7879 So it's only when 1/ and 2/ happens that we want to use the partial
7880 instantiation of the member template in lieu of its most general
7881 template. */
7885 /* the enclosing class must be an instantiation... */
7888 {
7889 tree partial_inst_args;
7892 partial_inst_args =
7898 use_partial_inst_tmpl =
7899 /*...and we must not be looking at the partial instantiation
7900 itself. */
7902 partial_inst_args);
7903 }
7906 /* This case is easy; there are no member templates involved. */
7908 else
7909 {
7910 /* This is a full instantiation of a member template. Find
7911 the partial instantiation of which this is an instance. */
7913 /* Temporarily reduce by one the number of levels in the ARGLIST
7914 so as to avoid comparing the last set of arguments. */
7918 /* FOUND is either a proper class type, or an alias
7919 template specialization. In the later case, it's a
7920 TYPE_DECL, resulting from the substituting of arguments
7921 for parameters in the TYPE_DECL of the alias template
7922 done earlier. So be careful while getting the template
7923 of FOUND. */
7927 }
7937 /* Note this use of the partial instantiation so we can check it
7938 later in maybe_process_partial_specialization. */
7945 /* Now that the type has been registered on the instantiations
7946 list, we set up the enumerators. Because the enumeration
7947 constants may involve the enumeration type itself, we make
7948 sure to register the type first, and then create the
7949 constants. That way, doing tsubst_expr for the enumeration
7950 constants won't result in recursive calls here; we'll find
7951 the instantiation and exit above. */
7955 /* If the type makes use of template parameters, the
7956 code that generates debugging information will crash. */
7959 /* Possibly limit visibility based on template args. */
7966 }
7967 }
7969 /* Wrapper for lookup_template_class_1. */
7971 tree
7974 {
7975 tree ret;
7981 }
7983 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST.
7984 If the ARGLIST refers to any template parameters, the type of the
7985 expression is the unknown_type_node since the template-id could
7986 refer to an explicit or partial specialization. */
7988 tree
7990 {
7991 tree type;
7994 else
7997 }
7999 \f
8000 struct pair_fn_data
8001 {
8002 tree_fn_t fn;
8004 /* True when we should also visit template parameters that occur in
8005 non-deduced contexts. */
8008 };
8010 /* Called from for_each_template_parm via walk_tree. */
8012 static tree
8014 {
8027 {
8031 /* Fall through. */
8054 /* Since we're not going to walk subtrees, we have to do this
8055 explicitly here. */
8059 /* Fall through. */
8062 /* Check the return type. */
8067 /* Check the parameter types. Since default arguments are not
8068 instantiated until they are needed, the TYPE_ARG_TYPES may
8069 contain expressions that involve template parameters. But,
8070 no-one should be looking at them yet. And, once they're
8071 instantiated, they don't contain template parameters, so
8072 there's no point in looking at them then, either. */
8073 {
8074 tree parm;
8081 /* Since we've already handled the TYPE_ARG_TYPES, we don't
8082 want walk_tree walking into them itself. */
8084 }
8102 /* Fall through. */
8118 /* Record template parameters such as `T' inside `TT<T>'. */
8122 /* Fall through. */
8134 /* A template template parameter is encountered. */
8140 /* Already substituted template template parameter */
8163 /* If there's no type, then this thing must be some expression
8164 involving template parameters. */
8186 }
8188 /* We didn't find any template parameters we liked. */
8190 }
8192 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
8193 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
8194 call FN with the parameter and the DATA.
8195 If FN returns nonzero, the iteration is terminated, and
8196 for_each_template_parm returns 1. Otherwise, the iteration
8197 continues. If FN never returns a nonzero value, the value
8198 returned by for_each_template_parm is 0. If FN is NULL, it is
8199 considered to be the function which always returns 1.
8201 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
8202 parameters that occur in non-deduced contexts. When false, only
8203 visits those template parameters that can be deduced. */
8205 static int
8209 {
8213 /* Set up. */
8218 /* Walk the tree. (Conceptually, we would like to walk without
8219 duplicates, but for_each_template_parm_r recursively calls
8220 for_each_template_parm, so we would need to reorganize a fair
8221 bit to use walk_tree_without_duplicates, so we keep our own
8222 visited list.) */
8225 else
8228 for_each_template_parm_r,
8232 /* Clean up. */
8234 {
8237 }
8240 }
8242 /* Returns true if T depends on any template parameter. */
8244 int
8246 {
8273 else
8274 {
8277 }
8282 }
8284 /* Returns true iff current_function_decl is an incompletely instantiated
8285 template. Useful instead of processing_template_decl because the latter
8286 is set to 0 during fold_non_dependent_expr. */
8288 bool
8290 {
8299 }
8301 /* Returns true if T depends on any template parameter with level LEVEL. */
8303 int
8305 {
8308 }
8310 /* Returns TRUE iff INST is an instantiation we don't need to do in an
8311 ill-formed translation unit, i.e. a variable or function that isn't
8312 usable in a constant expression. */
8316 {
8320 }
8322 /* Returns TRUE iff we should refuse to instantiate DECL because it's
8323 neglectable and instantiated from within an erroneous instantiation. */
8325 static bool
8327 {
8338 }
8346 /* We're starting to instantiate D; record the template instantiation context
8347 for diagnostics and to restore it later. */
8349 bool
8351 {
8353 }
8355 /* We're starting to instantiate D; record the template instantiation context
8356 at LOC for diagnostics and to restore it later. */
8358 bool
8360 {
8364 {
8367 max_tinst_depth);
8369 }
8371 /* If the current instantiation caused problems, don't let it instantiate
8372 anything else. Do allow deduction substitution and decls usable in
8373 constant expressions. */
8390 }
8392 /* We're done instantiating this template; return to the instantiation
8393 context. */
8395 void
8397 {
8398 /* Restore the filename and line number stashed away when we started
8399 this instantiation. */
8403 }
8405 /* We're instantiating a deferred template; restore the template
8406 instantiation context in which the instantiation was requested, which
8407 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
8409 static tree
8411 {
8423 }
8425 /* Returns the TINST_LEVEL which gives the original instantiation
8426 context. */
8430 {
8436 }
8438 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
8439 vector of template arguments, as for tsubst.
8441 Returns an appropriate tsubst'd friend declaration. */
8443 static tree
8445 {
8446 tree new_friend;
8451 /* This was a friend declared with an explicit template
8452 argument list, e.g.:
8454 friend void f<>(T);
8456 to indicate that f was a template instantiation, not a new
8457 function declaration. Now, we have to figure out what
8458 instantiation of what template. */
8459 {
8461 tree new_args;
8462 tree tmpl;
8465 /* Friend functions are looked up in the containing namespace scope.
8466 We must enter that scope, to avoid finding member functions of the
8467 current class with same name. */
8482 tsk_none);
8484 }
8488 /* The NEW_FRIEND will look like an instantiation, to the
8489 compiler, but is not an instantiation from the point of view of
8490 the language. For example, we might have had:
8492 template <class T> struct S {
8493 template <class U> friend void f(T, U);
8494 };
8496 Then, in S<int>, template <class U> void f(int, U) is not an
8497 instantiation of anything. */
8503 {
8507 }
8509 /* The mangled name for the NEW_FRIEND is incorrect. The function
8510 is not a template instantiation and should not be mangled like
8511 one. Therefore, we forget the mangling here; we'll recompute it
8512 later if we need it. */
8514 {
8517 }
8520 {
8521 tree old_decl;
8522 tree new_friend_template_info;
8523 tree new_friend_result_template_info;
8524 tree ns;
8527 /* We must save some information from NEW_FRIEND before calling
8528 duplicate decls since that function will free NEW_FRIEND if
8529 possible. */
8531 new_friend_is_defn =
8536 {
8537 /* This declaration is a `primary' template. */
8540 new_friend_result_template_info
8542 }
8543 else
8546 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8550 /* Inside pushdecl_namespace_level, we will push into the
8551 current namespace. However, the friend function should go
8552 into the namespace of the template. */
8562 {
8563 /* This new friend declaration matched an existing
8564 declaration. For example, given:
8566 template <class T> void f(T);
8567 template <class U> class C {
8568 template <class T> friend void f(T) {}
8569 };
8571 the friend declaration actually provides the definition
8572 of `f', once C has been instantiated for some type. So,
8573 old_decl will be the out-of-class template declaration,
8574 while new_friend is the in-class definition.
8576 But, if `f' was called before this point, the
8577 instantiation of `f' will have DECL_TI_ARGS corresponding
8578 to `T' but not to `U', references to which might appear
8579 in the definition of `f'. Previously, the most general
8580 template for an instantiation of `f' was the out-of-class
8581 version; now it is the in-class version. Therefore, we
8582 run through all specialization of `f', adding to their
8583 DECL_TI_ARGS appropriately. In particular, they need a
8584 new set of outer arguments, corresponding to the
8585 arguments for this class instantiation.
8587 The same situation can arise with something like this:
8589 friend void f(int);
8590 template <class T> class C {
8591 friend void f(T) {}
8592 };
8594 when `C<int>' is instantiated. Now, `f(int)' is defined
8595 in the class. */
8598 /* On the other hand, if the in-class declaration does
8599 *not* provide a definition, then we don't want to alter
8600 existing definitions. We can just leave everything
8601 alone. */
8602 ;
8603 else
8604 {
8608 /* Overwrite whatever template info was there before, if
8609 any, with the new template information pertaining to
8610 the declaration. */
8614 {
8615 /* We should have called reregister_specialization in
8616 duplicate_decls. */
8621 /* Instantiate it if the global has already been used. */
8625 }
8626 else
8627 {
8628 tree t;
8630 /* Indicate that the old function template is a partial
8631 instantiation. */
8639 /* Reassign any specializations already in the hash table
8640 to the new more general template, and add the
8641 additional template args. */
8645 {
8647 spec_entry elt;
8659 register_specialization
8662 }
8664 }
8665 }
8667 /* The information from NEW_FRIEND has been merged into OLD_DECL
8668 by duplicate_decls. */
8670 }
8671 }
8672 else
8673 {
8677 /* In the code
8678 template <class T> class C {
8679 template <class U> friend void C1<U>::f (); // case 1
8680 friend void C2<T>::f (); // case 2
8681 };
8682 we only need to make sure CONTEXT is a complete type for
8683 case 2. To distinguish between the two cases, we note that
8684 CONTEXT of case 1 remains dependent type after tsubst while
8685 this isn't true for case 2. */
8695 {
8697 /* do_friend adds the TEMPLATE_DECL for any member friend
8698 template even if it isn't a member template, i.e.
8699 template <class T> friend A<T>::f();
8700 Look through it in that case. */
8704 /* Check to see that the declaration is really present, and,
8705 possibly obtain an improved declaration. */
8710 }
8711 }
8714 }
8716 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8717 template arguments, as for tsubst.
8719 Returns an appropriate tsubst'd friend type or error_mark_node on
8720 failure. */
8722 static tree
8724 {
8725 tree friend_type;
8726 tree tmpl;
8727 tree context;
8730 {
8733 }
8738 {
8741 else
8743 }
8745 /* Look for a class template declaration. We look for hidden names
8746 because two friend declarations of the same template are the
8747 same. For example, in:
8749 struct A {
8750 template <typename> friend class F;
8751 };
8752 template <typename> struct B {
8753 template <typename> friend class F;
8754 };
8756 both F templates are the same. */
8760 /* But, if we don't find one, it might be because we're in a
8761 situation like this:
8763 template <class T>
8764 struct S {
8765 template <class U>
8766 friend struct S;
8767 };
8769 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8770 for `S<int>', not the TEMPLATE_DECL. */
8772 {
8775 }
8778 {
8779 /* The friend template has already been declared. Just
8780 check to see that the declarations match, and install any new
8781 default parameters. We must tsubst the default parameters,
8782 of course. We only need the innermost template parameters
8783 because that is all that redeclare_class_template will look
8784 at. */
8787 {
8788 tree parms;
8789 location_t saved_input_location;
8798 }
8801 }
8802 else
8803 {
8804 /* The friend template has not already been declared. In this
8805 case, the instantiation of the template class will cause the
8806 injection of this template into the global scope. */
8811 /* The new TMPL is not an instantiation of anything, so we
8812 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
8813 the new type because that is supposed to be the corresponding
8814 template decl, i.e., TMPL. */
8821 /* Inject this template into the global scope. */
8823 }
8826 {
8829 else
8831 }
8834 }
8836 /* Returns zero if TYPE cannot be completed later due to circularity.
8837 Otherwise returns one. */
8839 static int
8841 {
8851 else
8853 }
8857 /* Apply any attributes which had to be deferred until instantiation
8858 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
8859 ARGS, COMPLAIN, IN_DECL are as tsubst. */
8861 static void
8864 {
8866 tree t;
8871 {
8875 }
8878 {
8882 }
8883 else
8887 {
8892 {
8895 {
8902 {
8909 clauses
8913 else
8915 }
8916 /* If the first attribute argument is an identifier, don't
8917 pass it through tsubst. Attributes like mode, format,
8918 cleanup and several target specific attributes expect it
8919 unmodified. */
8922 {
8923 tree chain
8925 in_decl,
8930 chain);
8931 }
8932 else
8938 }
8939 else
8941 }
8944 }
8945 }
8947 /* Perform (or defer) access check for typedefs that were referenced
8948 from within the template TMPL code.
8949 This is a subroutine of instantiate_decl and instantiate_class_template.
8950 TMPL is the template to consider and TARGS is the list of arguments of
8951 that template. */
8953 static void
8955 {
8956 location_t saved_location;
8967 {
8979 /* Make access check error messages point to the location
8980 of the use of the typedef. */
8984 tf_warning_or_error);
8985 }
8987 }
8989 static tree
8991 {
8993 tree typedecl;
8994 tree pbinfo;
8995 tree base_list;
8997 tree fn_context;
9006 /* Figure out which template is being instantiated. */
9010 /* Determine what specialization of the original template to
9011 instantiate. */
9014 {
9017 }
9019 {
9020 /* This TYPE is actually an instantiation of a partial
9021 specialization. We replace the innermost set of ARGS with
9022 the arguments appropriate for substitution. For example,
9023 given:
9025 template <class T> struct S {};
9026 template <class T> struct S<T*> {};
9028 and supposing that we are instantiating S<int*>, ARGS will
9029 presently be {int*} -- but we need {int}. */
9032 }
9033 else
9034 {
9037 }
9039 /* If the template we're instantiating is incomplete, then clearly
9040 there's nothing we can do. */
9044 /* If we've recursively instantiated too many templates, stop. */
9048 /* Now we're really doing the instantiation. Mark the type as in
9049 the process of being defined. */
9052 /* We may be in the middle of deferred access check. Disable
9053 it now. */
9057 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
9062 /* Use #pragma pack from the template context. */
9068 /* Set the input location to the most specialized template definition.
9069 This is needed if tsubsting causes an error. */
9081 {
9084 /* Adjust visibility for template arguments. */
9086 }
9092 /* We should never instantiate a nested class before its enclosing
9093 class; we need to look up the nested class by name before we can
9094 instantiate it, and that lookup should instantiate the enclosing
9095 class. */
9101 {
9102 tree pbase_binfo;
9103 tree pushed_scope;
9106 /* We must enter the scope containing the type, as that is where
9107 the accessibility of types named in dependent bases are
9108 looked up from. */
9111 /* Substitute into each of the bases to determine the actual
9112 basetypes. */
9114 {
9115 tree base;
9121 {
9122 expanded_bases =
9129 }
9132 {
9134 /* Extract the already-expanded base class. */
9136 else
9137 /* Substitute to figure out the base class. */
9139 NULL_TREE);
9147 }
9148 }
9150 /* The list is now in reverse order; correct that. */
9155 }
9156 /* Now call xref_basetypes to set up all the base-class
9157 information. */
9165 /* Now that our base classes are set up, enter the scope of the
9166 class, so that name lookups into base classes, etc. will work
9167 correctly. This is precisely analogous to what we do in
9168 begin_class_definition when defining an ordinary non-template
9169 class, except we also need to push the enclosing classes. */
9172 /* Now members are processed in the order of declaration. */
9175 {
9179 {
9181 {
9182 /* Build new CLASSTYPE_NESTED_UTDS. */
9184 tree newtag;
9190 /* If the member is a class template, then -- even after
9191 substitution -- there may be dependent types in the
9192 template argument list for the class. We increment
9193 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
9194 that function will assume that no types are dependent
9195 when outside of a template. */
9205 {
9209 /* Unfortunately, lookup_template_class sets
9210 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
9211 instantiation (i.e., for the type of a member
9212 template class nested within a template class.)
9213 This behavior is required for
9214 maybe_process_partial_specialization to work
9215 correctly, but is not accurate in this case;
9216 the TAG is not an instantiation of anything.
9217 (The corresponding TEMPLATE_DECL is an
9218 instantiation, but the TYPE is not.) */
9221 /* Now, we call pushtag to put this NEWTAG into the scope of
9222 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
9223 pushtag calling push_template_decl. We don't have to do
9224 this for enums because it will already have been done in
9225 tsubst_enum. */
9229 }
9230 }
9232 {
9233 /* Build new TYPE_METHODS. */
9234 tree r;
9243 /* Instantiate members marked with attribute used. */
9249 }
9252 /* A closure type for a lambda in a default argument for a
9253 member template. Ignore it; it will be instantiated with
9255 else
9256 {
9257 /* Build new TYPE_FIELDS. */
9259 {
9260 tree condition;
9263 condition =
9273 }
9275 {
9276 tree r;
9280 /* The file and line for this declaration, to
9281 assist in error message reporting. Since we
9282 called push_tinst_level above, we don't need to
9283 restore these. */
9293 {
9294 /* A capture pack became multiple fields. */
9297 }
9300 {
9304 {
9305 /* In [temp.inst]:
9307 [t]he initialization (and any associated
9308 side-effects) of a static data member does
9309 not occur unless the static data member is
9310 itself used in a way that requires the
9311 definition of the static data member to
9312 exist.
9314 Therefore, we do not substitute into the
9315 initialized for the static data member here. */
9316 finish_static_data_member_decl
9322 /* Instantiate members marked with attribute used. */
9325 }
9327 {
9328 /* Determine whether R has a valid type and can be
9329 completed later. If R is invalid, then its type
9330 is replaced by error_mark_node. */
9336 {
9339 }
9340 }
9342 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
9343 such a thing will already have been added to the field
9344 list by tsubst_enum in finish_member_declaration in the
9345 CLASSTYPE_NESTED_UTDS case above. */
9349 {
9352 }
9353 }
9354 }
9355 }
9356 }
9357 else
9358 {
9361 {
9362 /* Build new CLASSTYPE_FRIEND_CLASSES. */
9368 {
9369 /* template <class T> friend class C; */
9372 }
9374 {
9375 /* template <class T> friend class C::D; */
9381 }
9384 {
9385 /* This could be either
9387 friend class T::C;
9389 when dependent_type_p is false or
9391 template <class U> friend class T::C;
9393 otherwise. */
9396 /* Bump processing_template_decl for correct
9397 dependent_type_p calculation. */
9402 }
9405 {
9406 /* friend class C;
9408 where C hasn't been declared yet. Let's lookup name
9409 from namespace scope directly, bypassing any name that
9410 come from dependent base class. */
9413 /* The call to xref_tag_from_type does injection for friend
9414 classes. */
9416 friend_type =
9420 }
9422 /* friend class C<T>; */
9425 /* Otherwise it's
9427 friend class C;
9429 where C is already declared or
9431 friend class C<int>;
9433 We don't have to do anything in these cases. */
9436 /* Trick make_friend_class into realizing that the friend
9437 we're adding is a template, not an ordinary class. It's
9438 important that we use make_friend_class since it will
9439 perform some error-checking and output cross-reference
9440 information. */
9448 }
9449 else
9450 {
9451 /* Build new DECL_FRIENDLIST. */
9452 tree r;
9454 /* The file and line for this declaration, to
9455 assist in error message reporting. Since we
9456 called push_tinst_level above, we don't need to
9457 restore these. */
9461 {
9464 }
9469 {
9472 }
9473 }
9474 }
9475 }
9478 {
9481 {
9486 /* We need to instantiate the capture list from the template
9487 after we've instantiated the closure members, but before we
9488 consider adding the conversion op. Also keep any captures
9489 that may have been added during instantiation of the op(). */
9491 tree tmpl_cap
9500 }
9501 else
9503 }
9505 /* Set the file and line number information to whatever is given for
9506 the class itself. This puts error messages involving generated
9507 implicit functions at a predictable point, and the same point
9508 that would be used for non-template classes. */
9515 /* We don't instantiate default arguments for member functions. 14.7.1:
9517 The implicit instantiation of a class template specialization causes
9518 the implicit instantiation of the declarations, but not of the
9519 definitions or default arguments, of the class member functions,
9520 member classes, static data members and member templates.... */
9522 /* Some typedefs referenced from within the template code need to be access
9523 checked at template instantiation time, i.e now. These types were
9524 added to the template at parsing time. Let's get those and perform
9525 the access checks then. */
9535 /* The vtable for a template class can be emitted in any translation
9536 unit in which the class is instantiated. When there is no key
9537 method, however, finish_struct_1 will already have added TYPE to
9538 the keyed_classes list. */
9543 }
9545 /* Wrapper for instantiate_class_template_1. */
9547 tree
9549 {
9550 tree ret;
9555 }
9557 static tree
9559 {
9560 tree r;
9566 else
9567 {
9574 }
9576 }
9578 /* Given a function parameter pack TMPL_PARM and some function parameters
9579 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
9580 and set *SPEC_P to point at the next point in the list. */
9582 static tree
9584 {
9585 /* Collect all of the extra "packed" parameters into an
9586 argument pack. */
9587 tree parmvec;
9588 tree parmtypevec;
9599 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
9604 {
9607 }
9609 /* Build the argument packs. */
9616 }
9618 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9619 NONTYPE_ARGUMENT_PACK. */
9621 static tree
9623 {
9625 }
9627 /* Return true iff the Ith element of the argument pack ARG_PACK is a
9628 pack expansion. */
9630 static bool
9632 {
9637 }
9640 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
9642 static tree
9644 {
9651 }
9653 /* This is a subroutine of tsubst_pack_expansion.
9655 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
9656 mechanism to store the (non complete list of) arguments of the
9657 substitution and return a non substituted pack expansion, in order
9658 to wait for when we have enough arguments to really perform the
9659 substitution. */
9661 static bool
9665 {
9666 /* If one pack has an expansion and another pack has a normal
9667 argument or if one pack has an empty argument and an another
9668 one hasn't then tsubst_pack_expansion cannot perform the
9669 substitution and need to fall back on the
9670 PACK_EXPANSION_EXTRA mechanism. */
9678 {
9681 parm_pack;
9683 {
9688 else
9690 }
9694 }
9696 }
9698 /* [temp.variadic]/6 says that:
9700 The instantiation of a pack expansion [...]
9701 produces a list E1,E2, ..., En, where N is the number of elements
9702 in the pack expansion parameters.
9704 This subroutine of tsubst_pack_expansion produces one of these Ei.
9706 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
9707 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
9708 PATTERN, and each TREE_VALUE is its corresponding argument pack.
9709 INDEX is the index 'i' of the element Ei to produce. ARGS,
9710 COMPLAIN, and IN_DECL are the same parameters as for the
9711 tsubst_pack_expansion function.
9713 The function returns the resulting Ei upon successful completion,
9714 or error_mark_node.
9716 Note that this function possibly modifies the ARGS parameter, so
9717 it's the responsibility of the caller to restore it. */
9719 static tree
9721 tree parm_packs,
9723 tree args /* This parm gets
9725 tsubst_flags_t complain,
9726 tree in_decl)
9727 {
9728 tree t;
9731 /* For each parameter pack, change the substitution of the parameter
9732 pack to the ith argument in its argument pack, then expand the
9733 pattern. */
9735 {
9740 ith_elem_is_expansion |=
9743 /* Select the Ith argument from the pack. */
9746 {
9748 {
9752 }
9753 else
9755 }
9756 else
9757 {
9762 {
9764 /* Update the corresponding argument. */
9766 }
9767 else
9768 /* Re-use the ARGUMENT_PACK_SELECT. */
9770 }
9772 }
9774 /* Substitute into the PATTERN with the (possibly altered)
9775 arguments. */
9777 /* Expanding a fixed parameter pack from
9778 coerce_template_parameter_pack. */
9783 else
9786 /* If the Ith argument pack element is a pack expansion, then
9787 the Ith element resulting from the substituting is going to
9788 be a pack expansion as well. */
9793 }
9795 /* Substitute ARGS into T, which is an pack expansion
9796 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
9797 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
9798 (if only a partial substitution could be performed) or
9799 ERROR_MARK_NODE if there was an error. */
9800 tree
9802 tree in_decl)
9803 {
9804 tree pattern;
9808 tree result;
9816 /* Add in any args remembered from an earlier partial instantiation. */
9821 /* Determine the argument packs that will instantiate the parameter
9822 packs used in the expansion expression. While we're at it,
9823 compute the number of arguments to be expanded and make sure it
9824 is consistent. */
9827 {
9834 {
9838 else
9841 }
9843 {
9846 else
9847 {
9848 /* We can't rely on local_specializations for a parameter
9849 name used later in a function declaration (such as in a
9850 late-specified return type). Even if it exists, it might
9851 have the wrong value for a recursive call. Just make a
9852 dummy decl, since it's only used for its type. */
9855 /* Partial instantiation of the parm_pack, we can't build
9856 up an argument pack yet. */
9858 else
9861 }
9862 }
9865 else
9866 {
9872 }
9879 /* This can only happen if we forget to expand an argument
9880 pack somewhere else. Just return an error, silently. */
9881 {
9885 }
9888 {
9892 /* Don't bother trying to do a partial substitution with
9893 incomplete packs; we'll try again after deduction. */
9900 {
9906 pattern);
9907 else
9910 pattern);
9912 }
9914 /* Keep track of the parameter packs and their corresponding
9915 argument packs. */
9918 }
9919 else
9920 {
9921 /* We can't substitute for this parameter pack. We use a flag as
9922 well as the missing_level counter because function parameter
9923 packs don't have a level. */
9925 }
9926 }
9928 /* If the expansion is just T..., return the matching argument pack. */
9931 {
9936 /* Otherwise use the normal path so we get convert_from_reference. */
9937 }
9939 /* We cannot expand this expansion expression, because we don't have
9940 all of the argument packs we need. */
9942 {
9943 /* We got some full packs, but we can't substitute them in until we
9944 have values for all the packs. So remember these until then. */
9949 }
9951 {
9952 /* There were no real arguments, we're just replacing a parameter
9953 pack with another version of itself. Substitute into the
9954 pattern and return a PACK_EXPANSION_*. The caller will need to
9955 deal with that. */
9959 else
9963 }
9968 {
9969 /* We're in a late-specified return type, so create our own local
9970 specializations map; the current map is either NULL or (in the
9971 case of recursive unification) might have bindings that we don't
9972 want to use or alter. */
9975 }
9977 /* For each argument in each argument pack, substitute into the
9978 pattern. */
9981 {
9983 i,
9985 in_decl);
9988 {
9991 }
9992 }
9994 /* Update ARGS to restore the substitution from parameter packs to
9995 their argument packs. */
9997 {
10003 else
10004 {
10012 /* Update the corresponding argument. */
10016 else
10018 }
10019 }
10022 {
10025 }
10028 }
10030 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
10031 TMPL. We do this using DECL_PARM_INDEX, which should work even with
10032 parameter packs; all parms generated from a function parameter pack will
10033 have the same DECL_PARM_INDEX. */
10035 tree
10037 {
10039 tree patparm;
10042 {
10048 }
10049 else
10050 {
10055 }
10058 }
10060 /* Substitute ARGS into the vector or list of template arguments T. */
10062 static tree
10064 {
10076 {
10078 tree new_arg;
10083 {
10084 /* Substitute into an expansion expression. */
10088 /* Add to the expanded length adjustment the number of
10089 expanded arguments. We subtract one from this
10090 measurement, because the argument pack expression
10091 itself is already counted as 1 in
10092 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
10093 the argument pack is empty. */
10095 }
10097 {
10098 /* Substitute into each of the arguments. */
10104 new_arg,
10118 }
10119 }
10120 else
10129 }
10134 /* Make space for the expanded arguments coming from template
10135 argument packs. */
10137 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
10138 arguments for a member template.
10139 In that case each TREE_VEC in ORIG_T represents a level of template
10140 arguments, and ORIG_T won't carry any non defaulted argument count.
10141 It will rather be the nested TREE_VECs that will carry one.
10142 In other words, ORIG_T carries a non defaulted argument count only
10143 if it doesn't contain any nested TREE_VEC. */
10145 {
10149 }
10151 {
10155 {
10158 /* Now expand the template argument pack "in place". */
10161 }
10162 else
10163 {
10165 out++;
10166 }
10167 }
10170 }
10172 /* Return the result of substituting ARGS into the template parameters
10173 given by PARMS. If there are m levels of ARGS and m + n levels of
10174 PARMS, then the result will contain n levels of PARMS. For
10175 example, if PARMS is `template <class T> template <class U>
10176 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
10177 result will be `template <int*, double, class V>'. */
10179 static tree
10181 {
10185 /* When substituting into a template, we must set
10186 PROCESSING_TEMPLATE_DECL as the template parameters may be
10187 dependent if they are based on one-another, and the dependency
10188 predicates are short-circuit outside of templates. */
10195 {
10196 tree new_vec =
10201 {
10202 tree tuple;
10214 }
10220 }
10225 }
10227 /* Return the result of substituting ARGS into one template parameter
10228 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
10229 parameter and which TREE_PURPOSE is the default argument of the
10230 template parameter. */
10232 static tree
10234 {
10255 }
10257 /* Substitute the ARGS into the indicated aggregate (or enumeration)
10258 type T. If T is not an aggregate or enumeration type, it is
10259 handled as if by tsubst. IN_DECL is as for tsubst. If
10260 ENTERING_SCOPE is nonzero, T is the context for a template which
10261 we are presently tsubst'ing. Return the substituted value. */
10263 static tree
10265 tree args,
10266 tsubst_flags_t complain,
10267 tree in_decl,
10269 {
10274 {
10279 /* Else fall through. */
10283 {
10284 tree argvec;
10285 tree context;
10286 tree r;
10290 /* In "sizeof(X<I>)" we need to evaluate "I". */
10296 /* First, determine the context for the type we are looking
10297 up. */
10300 {
10303 /* If context is a nested class inside a class template,
10304 it may still need to be instantiated (c++/33959). */
10306 }
10308 /* Then, figure out what arguments are appropriate for the
10309 type we are trying to find. For example, given:
10311 template <class T> struct S;
10312 template <class T, class U> void f(T, U) { S<U> su; }
10314 and supposing that we are instantiating f<int, double>,
10315 then our ARGS will be {int, double}, but, when looking up
10316 S we only want {double}. */
10321 else
10322 {
10326 }
10332 }
10333 else
10334 /* This is not a template type, so there's nothing to do. */
10339 }
10340 }
10342 /* Substitute into the default argument ARG (a default argument for
10343 FN), which has the indicated TYPE. */
10345 tree
10347 {
10352 /* This can happen in invalid code. */
10356 /* This default argument came from a template. Instantiate the
10357 default argument here, not in tsubst. In the case of
10358 something like:
10360 template <class T>
10361 struct S {
10362 static T t();
10363 void f(T = t());
10364 };
10366 we must be careful to do name lookup in the scope of S<T>,
10367 rather than in the current class. */
10369 /* The "this" pointer is not valid in a default argument. */
10371 {
10376 }
10379 /* The default argument expression may cause implicitly defined
10380 member functions to be synthesized, which will result in garbage
10381 collection. We must treat this situation as if we were within
10382 the body of function so as to avoid collecting live data on the
10383 stack. */
10391 /* Restore the "this" pointer. */
10393 {
10396 }
10403 /* Make sure the default argument is reasonable. */
10409 }
10411 /* Substitute into all the default arguments for FN. */
10413 static void
10415 {
10416 tree arg;
10417 tree tmpl_args;
10421 /* If this function is not yet instantiated, we certainly don't need
10422 its default arguments. */
10425 /* Don't do this again for clones. */
10430 arg;
10436 complain);
10437 }
10439 /* Substitute the ARGS into the T, which is a _DECL. Return the
10440 result of the substitution. Issue error and warning messages under
10441 control of COMPLAIN. */
10443 static tree
10445 {
10446 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
10447 location_t saved_loc;
10452 /* Set the filename and linenumber to improve error-reporting. */
10457 {
10459 {
10460 /* We can get here when processing a member function template,
10461 member class template, or template template parameter. */
10463 tree spec;
10464 tree tmpl_args;
10465 tree full_args;
10468 {
10469 /* Template template parameter is treated here. */
10473 /* If we get a real template back, return it. This can happen in
10474 the context of most_specialized_class. */
10486 complain);
10489 }
10491 /* We might already have an instance of this template.
10492 The ARGS are for the surrounding class type, so the
10493 full args contain the tsubst'd args for the context,
10494 plus the innermost args from the template decl. */
10498 /* Because this is a template, the arguments will still be
10499 dependent, even after substitution. If
10500 PROCESSING_TEMPLATE_DECL is not set, the dependency
10501 predicates will short-circuit. */
10509 /* If this is a default template template argument,
10510 tsubst might not have changed anything. */
10517 {
10520 }
10522 /* Make a new template decl. It will be similar to the
10523 original, but will record the current template arguments.
10524 We also create a new function declaration, which is just
10525 like the old one, but points to this new template, rather
10526 than the old one. */
10535 {
10536 tree new_type;
10544 /* For a partial specialization, we need to keep pointing to
10545 the primary template. */
10551 }
10552 else
10553 {
10554 tree new_decl;
10566 }
10572 /* The template parameters for this new template are all the
10573 template parameters for the old template, except the
10574 outermost level of parameters. */
10577 complain);
10583 /* Record this non-type partial instantiation. */
10587 }
10591 {
10592 tree ctx;
10595 tree gen_tmpl;
10596 tree type;
10601 /* Nobody should be tsubst'ing into non-template functions. */
10605 {
10606 tree spec;
10609 /* If T is not dependent, just return it. We have to
10610 increment PROCESSING_TEMPLATE_DECL because
10611 value_dependent_expression_p assumes that nothing is
10612 dependent when PROCESSING_TEMPLATE_DECL is zero. */
10619 /* Calculate the most general template of which R is a
10620 specialization, and the complete set of arguments used to
10621 specialize R. */
10624 (DECL_TEMPLATE_RESULT
10630 /* Check to see if we already have this specialization. */
10635 {
10638 }
10640 /* We can see more levels of arguments than parameters if
10641 there was a specialization of a member template, like
10642 this:
10644 template <class T> struct S { template <class U> void f(); }
10645 template <> template <class U> void S<int>::f(U);
10647 Here, we'll be substituting into the specialization,
10648 because that's where we can find the code we actually
10649 want to generate, but we'll have enough arguments for
10650 the most general template.
10652 We also deal with the peculiar case:
10654 template <class T> struct S {
10655 template <class U> friend void f();
10656 };
10657 template <class U> void f() {}
10658 template S<int>;
10659 template void f<double>();
10661 Here, the ARGS for the instantiation of will be {int,
10662 double}. But, we only need as many ARGS as there are
10663 levels of template parameters in CODE_PATTERN. We are
10664 careful not to get fooled into reducing the ARGS in
10665 situations like:
10667 template <class T> struct S { template <class U> void f(U); }
10668 template <class T> template <> void S<T>::f(int) {}
10670 which we can spot because the pattern will be a
10671 specialization in this case. */
10673 parms_depth =
10678 }
10679 else
10680 {
10681 /* This special case arises when we have something like this:
10683 template <class T> struct S {
10684 friend void f<int>(int, double);
10685 };
10687 Here, the DECL_TI_TEMPLATE for the friend declaration
10688 will be an IDENTIFIER_NODE. We are being called from
10689 tsubst_friend_function, and we want only to create a
10690 new decl (R) with appropriate types so that we can call
10691 determine_specialization. */
10693 }
10696 {
10699 else
10703 }
10704 else
10705 {
10708 }
10713 /* If we hit excessive deduction depth, the type is bogus even if
10714 it isn't error_mark_node, so don't build a decl. */
10718 /* We do NOT check for matching decls pushed separately at this
10719 point, as they may not represent instantiations of this
10720 template, and in any case are considered separate under the
10721 discrete model. */
10725 /* Clear out the mangled name and RTL for the instantiation. */
10728 /* Leave DECL_INITIAL set on deleted instantiations. */
10733 /* OpenMP UDRs have the only argument a reference to the declared
10734 type. We want to diagnose if the declared type is a reference,
10735 which is invalid, but as references to references are usually
10736 quietly merged, diagnose it here. */
10738 {
10739 tree argtype
10744 "reference type %qT in "
10748 argtype);
10749 }
10752 /* Type-conversion operator. Reconstruct the name, in
10753 case it's the name of one of the template's parameters. */
10763 /* If this is an instantiation of a function with internal
10764 linkage, we already know what object file linkage will be
10765 assigned to the instantiation. */
10774 /* We'll re-clone as appropriate in instantiate_template. */
10777 /* If we aren't complaining now, return on error before we register
10778 the specialization so that we'll complain eventually. */
10784 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
10785 this in the special friend case mentioned above where
10786 GEN_TMPL is NULL. */
10788 {
10793 tree new_r
10796 /* We instantiated this while substituting into
10797 the type earlier (template/friend54.C). */
10800 /* We're not supposed to instantiate default arguments
10801 until they are called, for a template. But, for a
10802 declaration like:
10804 template <class T> void f ()
10805 { extern void g(int i = T()); }
10807 we should do the substitution when the template is
10808 instantiated. We handle the member function case in
10809 instantiate_class_template since the default arguments
10810 might refer to other members of the class. */
10815 }
10816 else
10819 /* Copy the list of befriending classes. */
10823 {
10827 in_decl);
10828 }
10831 {
10837 /* If this is an instantiation of a member template, clone it.
10838 If it isn't, that'll be handled by
10839 clone_constructors_and_destructors. */
10842 }
10853 /* Possibly limit visibility based on template args. */
10856 {
10860 }
10868 }
10872 {
10880 {
10881 /* If there is a local specialization that isn't a
10882 parameter pack, it means that we're doing a "simple"
10883 substitution from inside tsubst_pack_expansion. Just
10884 return the local specialization (which will be a single
10885 parm). */
10892 /* Expand the TYPE_PACK_EXPANSION that provides the types for
10893 the parameters in this function parameter pack. */
10897 {
10900 /* Zero-length parameter packs are boring. Just substitute
10901 into the chain. */
10905 }
10906 else
10907 {
10908 /* All we did was update the type. Make a note of that. */
10911 }
10912 }
10914 /* Loop through all of the parameters we'll build. When T is
10915 a function parameter pack, LEN is the number of expanded
10916 types in EXPANDED_TYPES; otherwise, LEN is 1. */
10919 {
10926 /* We're on the Ith parameter of the function parameter
10927 pack. */
10928 {
10929 /* Get the Ith type. */
10932 /* Rename the parameter to include the index. */
10935 }
10937 /* We're dealing with a normal parameter. */
10945 {
10948 else
10951 }
10961 /* Keep track of the first new parameter we
10962 generate. That's what will be returned to the
10963 caller. */
10967 /* Build a proper chain of parameters when substituting
10968 into a function parameter pack. */
10971 }
10973 /* If cp_unevaluated_operand is set, we're just looking for a
10974 single dummy parameter, so don't keep going. */
10979 /* FIRST_R contains the start of the chain we've built. */
10981 }
10985 {
10992 {
10993 /* This field is a lambda capture pack. Return a TREE_VEC of
10994 the expanded fields to instantiate_class_template_1 and
10995 store them in the specializations hash table as a
10996 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
11000 {
11003 }
11004 else
11005 {
11006 /* All we did was update the type. Make a note of that. */
11009 }
11010 }
11013 {
11016 {
11020 }
11030 /* For bit-fields, DECL_INITIAL gives the number of bits. For
11031 non-bit-fields DECL_INITIAL is a non-static data member
11032 initializer, which gets deferred instantiation. */
11038 {
11039 /* Set up DECL_TEMPLATE_INFO so that we can get at the
11040 NSDMI in perform_member_init. Still set DECL_INITIAL
11041 so that we know there is one. */
11046 }
11047 /* We don't have to set DECL_CONTEXT here; it is set by
11048 finish_member_declaration. */
11056 }
11059 {
11067 }
11068 }
11072 /* We reach here only for member using decls. We also need to check
11073 uses_template_parms because DECL_DEPENDENT_P is not set for a
11074 using-declaration that designates a member of the current
11075 instantiation (c++/53549). */
11078 {
11085 else
11086 {
11089 }
11090 }
11091 else
11092 {
11095 }
11100 {
11103 tree spec;
11105 tree ctx;
11114 {
11115 /* If this is the canonical decl, we don't have to
11116 mess with instantiations, and often we can't (for
11117 typename, template type parms and such). Note that
11118 TYPE_NAME is not correct for the above test if
11119 we've copied the type for a typedef. */
11125 }
11127 /* Check to see if we already have the specialization we
11128 need. */
11131 {
11132 /* T is a static data member or namespace-scope entity.
11133 We have to substitute into namespace-scope variables
11134 (even though such entities are never templates) because
11135 of cases like:
11137 template <class T> void f() { extern T t; }
11139 where the entity referenced is not known until
11140 instantiation time. */
11144 {
11146 complain,
11148 /* If CTX is unchanged, then T is in fact the
11149 specialization we want. That situation occurs when
11150 referencing a static data member within in its own
11151 class. We can use pointer equality, rather than
11152 same_type_p, because DECL_CONTEXT is always
11153 canonical... */
11155 /* ... unless T is a member template; in which
11156 case our caller can be willing to create a
11157 specialization of that template represented
11158 by T. */
11162 }
11165 {
11173 }
11174 }
11175 else
11176 {
11177 /* A local variable. */
11179 /* Subsequent calls to pushdecl will fill this in. */
11182 }
11183 /* If we already have the specialization we need, there is
11184 nothing more to do. */
11186 {
11189 }
11191 /* Create a new node for the specialization we need. */
11194 {
11197 else
11204 }
11206 {
11207 /* Even if the original location is out of scope, the
11208 newly substituted one is not. */
11215 {
11216 /* It may seem that this case cannot occur, since:
11218 typedef void f();
11219 void g() { f x; }
11221 declares a function, not a variable. However:
11223 typedef void f();
11224 template <typename T> void g() { T t; }
11225 template void g<f>();
11227 is an attempt to declare a variable with function
11228 type. */
11230 /* R is not yet sufficiently initialized, so we
11231 just use its name. */
11234 }
11236 /* Wait until cp_finish_decl to set this again, to handle
11237 circular dependency (template/instantiate6.C). */
11242 {
11247 {
11250 }
11252 }
11255 }
11261 /* Clear out the mangled name and RTL for the instantiation. */
11265 /* The initializer must not be expanded until it is required;
11266 see [temp.inst]. */
11272 {
11273 /* Possibly limit visibility based on template args. */
11276 {
11280 }
11282 }
11285 {
11286 /* A static data member declaration is always marked
11287 external when it is declared in-class, even if an
11288 initializer is present. We mimic the non-template
11289 processing here. */
11295 }
11305 /* Preserve a typedef that names a type. */
11307 {
11310 }
11313 }
11318 }
11319 #undef RETURN
11321 out:
11322 /* Restore the file and line information. */
11326 }
11328 /* Substitute into the ARG_TYPES of a function type.
11329 If END is a TREE_CHAIN, leave it and any following types
11330 un-substituted. */
11332 static tree
11334 tree args,
11335 tree end,
11336 tsubst_flags_t complain,
11337 tree in_decl)
11338 {
11339 tree remaining_arg_types;
11343 tree default_arg;
11354 {
11355 /* For a pack expansion, perform substitution on the
11356 entire expression. Later on, we'll handle the arguments
11357 one-by-one. */
11362 /* So that we'll spin through the parameters, one by one. */
11364 else
11365 {
11366 /* We only partially substituted into the parameter
11367 pack. Our type is TYPE_PACK_EXPANSION. */
11370 }
11371 }
11384 {
11386 {
11390 }
11392 }
11393 /* DR 657. */
11397 /* Do array-to-pointer, function-to-pointer conversion, and ignore
11398 top-level qualifiers as required. */
11401 /* We do not substitute into default arguments here. The standard
11402 mandates that they be instantiated only when needed, which is
11403 done in build_over_call. */
11407 {
11408 /* We've instantiated a template before its default arguments
11409 have been parsed. This can happen for a nested template
11410 class, and is not an error unless we require the default
11411 argument in a call of this function. */
11412 remaining_arg_types =
11415 }
11416 else
11417 remaining_arg_types =
11419 }
11422 }
11424 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
11425 *not* handle the exception-specification for FNTYPE, because the
11426 initial substitution of explicitly provided template parameters
11427 during argument deduction forbids substitution into the
11428 exception-specification:
11430 [temp.deduct]
11432 All references in the function type of the function template to the
11433 corresponding template parameters are replaced by the specified tem-
11434 plate argument values. If a substitution in a template parameter or
11435 in the function type of the function template results in an invalid
11436 type, type deduction fails. [Note: The equivalent substitution in
11437 exception specifications is done only when the function is instanti-
11438 ated, at which point a program is ill-formed if the substitution
11439 results in an invalid type.] */
11441 static tree
11443 tree args,
11444 tsubst_flags_t complain,
11445 tree in_decl)
11446 {
11447 tree return_type;
11449 tree fntype;
11451 /* The TYPE_CONTEXT is not used for function/method types. */
11454 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
11455 failure. */
11459 {
11460 /* Substitute the argument types. */
11472 {
11473 /* DR 1207: 'this' is in scope in the trailing return type. */
11475 }
11477 /* Substitute the return type. */
11481 {
11484 }
11485 }
11486 else
11487 /* Substitute the return type. */
11492 /* DR 486 clarifies that creation of a function type with an
11493 invalid return type is a deduction failure. */
11496 {
11498 {
11501 else
11503 }
11505 }
11506 /* And DR 657. */
11511 {
11512 /* Substitute the argument types. */
11517 }
11519 /* Construct a new type node and return it. */
11521 {
11526 }
11527 else
11528 {
11530 /* Don't pick up extra function qualifiers from the basetype. */
11533 {
11534 /* [temp.deduct]
11536 Type deduction may fail for any of the following
11537 reasons:
11539 -- Attempting to create "pointer to member of T" when T
11540 is not a class type. */
11543 r);
11545 }
11550 }
11557 }
11559 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
11560 ARGS into that specification, and return the substituted
11561 specification. If there is no specification, return NULL_TREE. */
11563 static tree
11565 tree args,
11566 tsubst_flags_t complain,
11567 tree in_decl,
11569 {
11570 tree specs;
11571 tree new_specs;
11576 {
11577 /* A noexcept-specifier. */
11582 {
11583 /* Defer instantiation of noexcept-specifiers to avoid
11584 excessive instantiations (c++/49107). */
11587 {
11588 /* We already partially instantiated this member template,
11589 so combine the new args with the old. */
11594 }
11595 else
11596 {
11599 }
11600 }
11601 else
11602 new_specs = tsubst_copy_and_build
11606 }
11608 {
11611 else
11613 {
11614 tree spec;
11619 {
11620 /* Expand the pack expansion type. */
11623 in_decl);
11629 else
11630 {
11631 /* We're substituting into a member template, so
11632 we got a TYPE_PACK_EXPANSION back. Add that
11633 expansion and move on. */
11637 expanded_specs,
11638 complain);
11641 }
11642 }
11645 {
11648 else
11653 complain);
11654 }
11657 }
11658 }
11660 }
11662 /* Take the tree structure T and replace template parameters used
11663 therein with the argument vector ARGS. IN_DECL is an associated
11664 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
11665 Issue error and warning messages under control of COMPLAIN. Note
11666 that we must be relatively non-tolerant of extensions here, in
11667 order to preserve conformance; if we allow substitutions that
11668 should not be allowed, we may allow argument deductions that should
11669 not succeed, and therefore report ambiguous overload situations
11670 where there are none. In theory, we could allow the substitution,
11671 but indicate that it should have failed, and allow our caller to
11672 make sure that the right thing happens, but we don't try to do this
11673 yet.
11675 This function is used for dealing with types, decls and the like;
11676 for expressions, use tsubst_expr or tsubst_copy. */
11678 tree
11680 {
11703 else
11708 /* Reuse typedefs. We need to do this to handle dependent attributes,
11709 such as attribute aligned. */
11712 {
11716 {
11717 /* DECL represents an alias template and we want to
11718 instantiate it. */
11722 }
11726 {
11730 }
11735 else
11736 /* The typedef is from a non-template context. */
11740 {
11742 r = cp_build_qualified_type_real
11746 }
11747 else
11748 {
11749 /* We don't have an instantiation yet, so drop the typedef. */
11754 }
11755 }
11768 {
11794 {
11800 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
11801 needed. */
11807 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
11808 with TREE_SIDE_EFFECTS that indicates this is not an integral
11809 constant expression. */
11812 {
11815 }
11818 }
11824 {
11837 {
11841 {
11842 /* See through ARGUMENT_PACK_SELECT arguments. */
11844 /* If the selected argument is an expansion E, that most
11845 likely means we were called from
11846 gen_elem_of_pack_expansion_instantiation during the
11847 substituting of pack an argument pack (which Ith
11848 element is a pack expansion, where I is
11849 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
11850 In this case, the Ith element resulting from this
11851 substituting is going to be a pack expansion, which
11852 pattern is the pattern of E. Let's return the
11853 pattern of E, and
11854 gen_elem_of_pack_expansion_instantiation will
11855 build the resulting pack expansion from it. */
11857 {
11858 /* Make sure we aren't throwing away arg info. */
11861 }
11862 }
11863 }
11868 {
11870 /* If ARG is an argument pack, we don't actually want to
11871 perform a substitution here, because substitutions
11872 for argument packs are only done
11873 element-by-element. We can get to this point when
11874 substituting the type of a non-type template
11875 parameter pack, when that type actually contains
11876 template parameter packs from an outer template, e.g.,
11878 template<typename... Types> struct A {
11879 template<Types... Values> struct B { };
11880 }; */
11884 {
11890 return cp_build_qualified_type_real
11892 }
11894 {
11895 /* We are processing a type constructed from a
11896 template template parameter. */
11907 /* Consider this code:
11909 template <template <class> class Template>
11910 struct Internal {
11911 template <class Arg> using Bind = Template<Arg>;
11912 };
11914 template <template <class> class Template, class Arg>
11915 using Instantiate = Template<Arg>; //#0
11917 template <template <class> class Template,
11918 class Argument>
11919 using Bind =
11920 Instantiate<Internal<Template>::template Bind,
11921 Argument>; //#1
11923 When #1 is parsed, the
11924 BOUND_TEMPLATE_TEMPLATE_PARM representing the
11925 parameter `Template' in #0 matches the
11926 UNBOUND_CLASS_TEMPLATE representing the argument
11927 `Internal<Template>::template Bind'; We then want
11928 to assemble the type `Bind<Argument>' that can't
11929 be fully created right now, because
11930 `Internal<Template>' not being complete, the Bind
11931 template cannot be looked up in that context. So
11932 we need to "store" `Bind<Argument>' for later
11933 when the context of Bind becomes complete. Let's
11934 store that in a TYPENAME_TYPE. */
11938 argvec),
11939 typename_type,
11940 complain);
11942 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
11943 are resolving nested-types in the signature of a
11944 member function templates. Otherwise ARG is a
11945 TEMPLATE_DECL and is the real template to be
11946 instantiated. */
11954 complain);
11955 return cp_build_qualified_type_real
11957 }
11958 else
11959 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
11961 }
11964 /* This can happen during the attempted tsubst'ing in
11965 unify. This means that we don't yet have any information
11966 about the template parameter in question. */
11969 /* Early in template argument deduction substitution, we don't
11970 want to reduce the level of 'auto', or it will be confused
11971 with a normal template parm in subsequent deduction. */
11975 /* If we get here, we must have been looking at a parm for a
11976 more deeply nested template. Make a new version of this
11977 template parameter, but with a lower level. */
11979 {
11984 {
11986 r = cp_build_qualified_type_real
11990 }
11991 else
11992 {
12003 /* We have reduced the level of the template
12004 template parameter, but not the levels of its
12005 template parameters, so canonical_type_parameter
12006 will not be able to find the canonical template
12007 template parameter for this level. Thus, we
12008 require structural equality checking to compare
12009 TEMPLATE_TEMPLATE_PARMs. */
12013 else
12017 {
12025 }
12026 }
12035 }
12038 }
12041 {
12049 {
12053 }
12056 {
12060 }
12063 {
12067 }
12073 }
12076 /* We should never be tsubsting a binfo. */
12080 /* A vector of template arguments. */
12086 {
12090 /* [temp.deduct]
12092 Type deduction may fail for any of the following
12093 reasons:
12095 -- Attempting to create a pointer to reference type.
12096 -- Attempting to create a reference to a reference type or
12097 a reference to void.
12099 Core issue 106 says that creating a reference to a reference
12100 during instantiation is no longer a cause for failure. We
12101 only enforce this check in strict C++98 mode. */
12105 {
12108 /* We keep track of the last time we issued this error
12109 message to avoid spewing a ton of messages during a
12110 single bad template instantiation. */
12113 {
12118 else
12121 }
12124 }
12128 {
12130 {
12133 type);
12134 else
12136 type);
12137 }
12139 }
12141 {
12145 }
12147 /* In C++0x, during template argument substitution, when there is an
12148 attempt to create a reference to a reference type, reference
12149 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
12151 "If a template-argument for a template-parameter T names a type
12152 that is a reference to a type A, an attempt to create the type
12153 'lvalue reference to cv T' creates the type 'lvalue reference to
12154 A,' while an attempt to create the type type rvalue reference to
12155 cv T' creates the type T"
12156 */
12157 r = cp_build_reference_type
12160 else
12168 {
12170 pedwarn
12172 code == REFERENCE_TYPE
12175 else
12177 }
12180 /* Will this ever be needed for TYPE_..._TO values? */
12184 }
12186 {
12189 {
12190 /* [temp.deduct]
12192 Type deduction may fail for any of the following
12193 reasons:
12195 -- Attempting to create "pointer to member of T" when T
12196 is not a class type. */
12200 }
12202 {
12206 }
12208 {
12212 }
12215 {
12216 /* The type of the implicit object parameter gets its
12217 cv-qualifiers from the FUNCTION_TYPE. */
12218 tree memptr;
12219 tree method_type
12224 complain);
12225 }
12226 else
12229 complain);
12230 }
12233 {
12234 tree fntype;
12235 tree specs;
12240 /* Substitute the exception specification. */
12248 }
12250 {
12255 /* As an optimization, we avoid regenerating the array type if
12256 it will obviously be the same as T. */
12260 /* These checks should match the ones in create_array_type_for_decl.
12262 [temp.deduct]
12264 The deduction may fail for any of the following reasons:
12266 -- Attempting to create an array with an element type that
12267 is void, a function type, or a reference type, or [DR337]
12268 an abstract class type. */
12274 {
12278 }
12286 {
12289 }
12292 }
12295 {
12305 {
12309 }
12311 {
12312 /* Normally, make_typename_type does not require that the CTX
12313 have complete type in order to allow things like:
12315 template <class T> struct S { typename S<T>::X Y; };
12317 But, such constructs have already been resolved by this
12318 point, so here CTX really should have complete type, unless
12319 it's a partial instantiation. */
12322 {
12326 }
12327 }
12334 {
12337 }
12340 {
12342 {
12346 else
12348 }
12350 {
12354 else
12356 }
12357 }
12359 return cp_build_qualified_type_real
12361 }
12364 {
12376 }
12379 {
12380 tree type;
12396 complain);
12397 }
12400 {
12401 tree type;
12419 else
12420 {
12424 /* In a template ~id could be either a complement expression
12425 or an unqualified-id naming a destructor; if instantiating
12426 it produces an expression, it's not an id-expression or
12427 member access. */
12430 }
12434 complain);
12435 }
12438 {
12442 }
12446 {
12448 tree packed_out =
12450 args,
12451 complain,
12452 in_decl);
12455 /* For template nontype argument packs, also substitute into
12456 the type. */
12461 }
12477 /* We should use one of the expression tsubsts for these codes. */
12483 }
12484 }
12486 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
12487 type of the expression on the left-hand side of the "." or "->"
12488 operator. */
12490 static tree
12493 {
12494 tree name;
12495 tree qualifying_scope;
12496 tree fns;
12497 tree optype;
12502 /* A baselink indicates a function from a base class. Both the
12503 BASELINK_ACCESS_BINFO and the base class referenced may
12504 indicate bases of the template class, rather than the
12505 instantiated class. In addition, lookups that were not
12506 ambiguous before may be ambiguous now. Therefore, we perform
12507 the lookup again. */
12514 {
12521 }
12529 /* If lookup found a single function, mark it as used at this
12530 point. (If it lookup found multiple functions the one selected
12531 later by overload resolution will be marked as used at that
12532 point.) */
12538 /* Add back the template arguments, if present. */
12543 template_args);
12544 /* Update the conversion operator type. */
12552 qualifying_scope,
12553 object_type);
12555 }
12557 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
12558 true if the qualified-id will be a postfix-expression in-and-of
12559 itself; false if more of the postfix-expression follows the
12560 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
12561 of "&". */
12563 static tree
12567 {
12568 tree expr;
12569 tree scope;
12570 tree name;
12572 tree template_args;
12577 /* Figure out what name to look up. */
12580 {
12588 }
12589 else
12590 {
12593 }
12595 /* Substitute into the qualifying scope. When there are no ARGS, we
12596 are just trying to simplify a non-dependent expression. In that
12597 case the qualifying scope may be dependent, and, in any case,
12598 substituting will not help. */
12601 {
12604 }
12605 else
12609 {
12614 }
12617 {
12619 {
12620 /* A BIT_NOT_EXPR is used to represent a destructor. */
12622 {
12626 }
12627 else
12630 }
12631 else
12635 {
12637 {
12641 }
12643 }
12644 }
12647 {
12649 scope);
12650 /* Remember that there was a reference to this entity. */
12652 }
12655 {
12661 }
12670 {
12671 expr = (adjust_result_of_qualified_name_lookup
12673 expr = (finish_qualified_id_expr
12677 }
12679 /* Expressions do not generally have reference type. */
12681 /* However, if we're about to form a pointer-to-member, we just
12682 want the referenced member referenced. */
12687 }
12689 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
12690 initializer, DECL is the substituted VAR_DECL. Other arguments are as
12691 for tsubst. */
12693 static tree
12696 {
12703 {
12704 /* If we had an initializer but it
12705 instantiated to nothing,
12706 value-initialize the object. This will
12707 only occur when the initializer was a
12708 pack expansion where the parameter packs
12709 used in that expansion were of length
12710 zero. */
12712 complain);
12715 }
12718 }
12720 /* Like tsubst, but deals with expressions. This function just replaces
12721 template parms; to finish processing the resultant expression, use
12722 tsubst_copy_and_build or tsubst_expr. */
12724 static tree
12726 {
12728 tree r;
12736 {
12741 {
12742 /* We get here for a use of 'this' in an NSDMI. */
12744 && current_function_decl
12748 /* This can happen for a parameter name used later in a function
12749 declaration (such as in a late-specified return type). Just
12750 make a dummy decl, since it's only used for its type. */
12753 /* Give it the template pattern as its context; its true context
12754 hasn't been instantiated yet and this is good enough for
12755 mangling. */
12757 }
12765 {
12766 tree enum_type;
12767 tree v;
12771 /* There is no need to substitute into namespace-scope
12772 enumerators. */
12775 /* If ARGS is NULL, then T is known to be non-dependent. */
12779 /* Unfortunately, we cannot just call lookup_name here.
12780 Consider:
12782 template <int I> int f() {
12783 enum E { a = I };
12784 struct S { void g() { E e = a; } };
12785 };
12787 When we instantiate f<7>::S::g(), say, lookup_name is not
12788 clever enough to find f<7>::a. */
12789 enum_type
12799 /* We didn't find the name. That should never happen; if
12800 name-lookup found it during preliminary parsing, we
12801 should find it again here during instantiation. */
12803 }
12808 {
12809 /* Check for a local specialization set up by
12810 tsubst_pack_expansion. */
12812 {
12816 }
12818 /* When retrieving a capture pack from a generic lambda, remove the
12819 lambda call op's own template argument list from ARGS. Only the
12820 template arguments active for the closure type should be used to
12821 retrieve the pack specialization. */
12827 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
12828 tsubst_decl put in the hash table. */
12830 }
12833 {
12834 tree ctx;
12839 {
12842 {
12846 }
12848 }
12849 }
12858 {
12861 {
12862 /* First try name lookup to find the instantiation. */
12865 {
12866 /* Make sure that the one we found is the one we want. */
12871 }
12875 else
12876 {
12877 /* This can happen for a variable used in a
12878 late-specified return type of a local lambda, or for a
12879 local static or constant. Building a new VAR_DECL
12880 should be OK in all those cases. */
12883 {
12884 /* We can't call cp_finish_decl, so handle the
12885 initializer by hand. */
12896 }
12901 {
12904 at_eof);
12906 /* A use of a local constant decays to its value.
12907 FIXME update for core DR 696. */
12909 }
12910 }
12911 /* Remember this for subsequent uses. */
12914 }
12915 }
12916 else
12925 /* An OVERLOAD will always be a non-dependent overload set; an
12926 overload set from function scope will just be represented with an
12927 IDENTIFIER_NODE, and from class scope with a BASELINK. */
12943 {
12944 /* Template template argument like the following example need
12945 special treatment:
12947 template <template <class> class TT> struct C {};
12948 template <class T> struct D {
12949 template <class U> struct E {};
12950 C<E> c; // #1
12951 };
12952 D<int> d; // #2
12954 We are processing the template argument `E' in #1 for
12955 the template instantiation #2. Originally, `E' is a
12956 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
12957 have to substitute this with one having context `D<int>'. */
12961 }
12962 else
12963 /* Ordinary template template argument. */
12974 {
12978 }
12982 {
12992 /* We only want to compute the number of arguments. */
13006 {
13013 else
13016 }
13017 else
13019 }
13021 {
13029 }
13030 /* Fall through */
13046 {
13050 }
13053 {
13054 tree object;
13055 tree name;
13060 {
13064 }
13067 {
13077 }
13082 in_decl);
13083 else
13086 }
13124 {
13128 }
13131 {
13136 }
13139 {
13143 }
13146 {
13154 }
13160 {
13167 }
13170 {
13177 }
13180 {
13187 }
13190 {
13191 /* Substituted template arguments */
13200 }
13203 {
13223 }
13248 /* Fall through. */
13251 {
13254 }
13255 else
13259 /* This is handled by tsubst_copy_and_build. */
13263 {
13267 }
13270 /* We shouldn't have built any of these during initial template
13271 generation. Instead, they should be built during instantiation
13272 in response to the saved STMT_IS_FULL_EXPR_P setting. */
13276 {
13284 }
13302 {
13303 /* Instantiate any typedefs in the type. */
13308 }
13311 /* These can sometimes show up in a partial instantiation, but never
13312 involve template parms. */
13317 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
13320 }
13321 }
13323 /* Like tsubst_copy, but specifically for OpenMP clauses. */
13325 static tree
13328 {
13332 {
13338 {
13341 {
13347 }
13348 /* FALLTHRU */
13376 {
13379 {
13386 }
13387 else
13389 }
13419 }
13420 }
13426 }
13428 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
13430 static tree
13432 tree in_decl)
13433 {
13434 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
13454 {
13457 else
13458 {
13462 }
13463 }
13468 #undef RECUR
13469 }
13471 /* Substitute one OMP_FOR iterator. */
13473 static void
13478 {
13479 #define RECUR(NODE) \
13480 tsubst_expr ((NODE), args, complain, in_decl, \
13481 integral_constant_expression_p)
13490 {
13491 /* We need to jump through some hoops to handle declarations in the
13492 for-init-statement, since we might need to handle auto deduction,
13493 but we need to keep control of initialization. */
13497 }
13498 else
13510 {
13512 {
13513 /* Declare the variable, but don't let that initialize it. */
13518 }
13523 {
13528 }
13529 else
13536 }
13539 {
13540 /* Declare and initialize the variable. */
13543 }
13545 {
13546 tree c;
13548 {
13559 }
13561 {
13566 {
13569 }
13570 }
13571 }
13574 {
13578 }
13579 else
13583 {
13594 {
13602 }
13603 else
13609 {
13615 }
13619 {
13627 }
13628 else
13634 }
13640 #undef RECUR
13641 }
13643 /* Like tsubst_copy for expressions, etc. but also does semantic
13644 processing. */
13646 static tree
13649 {
13650 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13651 #define RECUR(NODE) \
13652 tsubst_expr ((NODE), args, complain, in_decl, \
13653 integral_constant_expression_p)
13656 tree r;
13657 location_t loc;
13669 {
13671 {
13672 tree_stmt_iterator i;
13676 }
13691 else
13700 {
13702 tree init;
13708 {
13711 tree decl;
13719 else
13721 }
13723 {
13724 /* Don't build up decls for a variadic capture proxy, we'll
13725 instantiate the elements directly as needed. */
13727 }
13728 else
13729 {
13733 {
13734 /* By marking the declaration as instantiated, we avoid
13735 trying to instantiate it. Since instantiate_decl can't
13736 handle local variables, and since we've already done
13737 all that needs to be done, that's the right thing to
13738 do. */
13743 /* Anonymous aggregates are a special case. */
13746 {
13749 {
13753 }
13755 }
13761 {
13766 }
13767 else
13768 {
13773 {
13774 /* For __PRETTY_FUNCTION__ we have to adjust the
13775 initializer. */
13779 }
13780 else
13784 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
13787 }
13788 }
13789 }
13792 }
13807 {
13817 }
13844 {
13848 }
13856 else
13864 else
13885 {
13889 }
13893 {
13895 tree label;
13900 }
13906 /* Computed goto's must be tsubst'd into. On the other hand,
13907 non-computed gotos must not be; the identifier in question
13908 will have no binding. */
13910 else
13916 {
13932 }
13937 {
13942 }
13943 else
13944 {
13949 else
13956 else
13962 else
13964 }
13968 {
13972 {
13974 /* Prevent instantiate_decl from trying to instantiate
13975 this variable. We've already done all that needs to be
13976 done. */
13979 }
13984 }
13990 {
13991 /* Local classes are not independent templates; they are
13992 instantiated along with their containing function. And this
13993 way we don't have to deal with pushing out of one local class
13994 to instantiate a member of another local class. */
13995 tree fn;
13996 /* Closures are handled by the LAMBDA_EXPR. */
14002 }
14006 {
14007 tree condition;
14010 condition =
14012 args,
14021 }
14046 {
14055 {
14060 }
14072 integral_constant_expression_p);
14081 else
14082 {
14090 }
14093 }
14152 {
14157 {
14160 }
14166 }
14167 else
14168 {
14175 {
14178 }
14181 {
14186 {
14189 }
14195 }
14196 else
14197 {
14201 }
14204 }
14208 {
14214 {
14218 {
14223 }
14227 }
14228 else
14229 {
14234 }
14235 }
14239 {
14243 }
14263 /* If the first operand was a statement, we're done with it. */
14267 complain));
14279 integral_constant_expression_p));
14280 }
14283 out:
14286 #undef RECUR
14287 #undef RETURN
14288 }
14290 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
14291 function. For description of the body see comment above
14292 cp_parser_omp_declare_reduction_exprs. */
14294 static void
14296 {
14302 tree_stmt_iterator tsi;
14313 {
14332 }
14334 {
14354 }
14355 }
14357 /* T is a postfix-expression that is not being used in a function
14358 call. Return the substituted version of T. */
14360 static tree
14362 tsubst_flags_t complain,
14363 tree in_decl)
14364 {
14368 else
14374 }
14376 /* Sentinel to disable certain warnings during template substitution. */
14384 };
14386 /* Like tsubst but deals with expressions and performs semantic
14387 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
14389 tree
14391 tree args,
14392 tsubst_flags_t complain,
14393 tree in_decl,
14396 {
14397 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
14398 #define RECUR(NODE) \
14399 tsubst_copy_and_build (NODE, args, complain, in_decl, \
14401 integral_constant_expression_p)
14404 location_t loc;
14413 /* N3276 decltype magic only applies to calls at the top level or on the
14414 right side of a comma. */
14419 {
14422 /* Fall through. */
14424 {
14425 tree decl;
14426 cp_id_kind idk;
14431 {
14434 }
14436 /* Look up the name. */
14439 /* By convention, expressions use ERROR_MARK_NODE to indicate
14440 failure, not NULL_TREE. */
14446 integral_constant_expression_p,
14454 input_location);
14458 {
14462 }
14464 }
14467 {
14468 tree object;
14476 {
14479 }
14480 else
14487 else
14489 }
14492 {
14496 {
14497 /* A type conversion to reference type will be enclosed in
14498 such an indirect ref, but the substitution of the cast
14499 will have also added such an indirect ref. */
14502 }
14503 else
14507 }
14510 {
14514 }
14517 {
14524 flags));
14525 }
14528 {
14532 }
14539 {
14540 tree type;
14546 {
14551 }
14557 {
14575 }
14578 }
14612 else
14614 in_decl);
14649 {
14654 tree r = build_x_binary_op
14656 op0,
14658 ? ERROR_MARK
14660 op1,
14662 ? ERROR_MARK
14670 }
14673 {
14677 }
14690 {
14699 }
14703 /* Fall through */
14706 {
14707 tree r;
14713 {
14714 /* When there are no ARGS, we are trying to evaluate a
14715 non-dependent expression from the parser. Trying to do
14716 the substitutions may not work. */
14719 }
14720 else
14721 {
14726 else
14729 /*integral_constant_expression_p=*/
14733 }
14737 else
14741 {
14743 {
14745 {
14749 }
14750 else
14754 }
14756 }
14758 }
14761 {
14771 }
14787 {
14791 tree r = build_x_modify_expr
14794 /* TREE_NO_WARNING must be set if either the expression was
14795 parenthesized or it uses an operator such as >>= rather
14796 than plain assignment. In the former case, it was already
14797 set and must be copied. In the latter case,
14798 build_x_modify_expr sets it and it must not be reset
14799 here. */
14804 }
14809 /* Remember that there was a reference to this entity. */
14815 {
14820 tree ret;
14824 else
14825 {
14829 }
14831 /* If there was an initializer in the original tree, but it
14832 instantiated to an empty list, then we should pass a
14833 non-NULL empty vector to tell build_new that it was an
14834 empty initializer() rather than no initializer. This can
14835 only happen when the initializer is a pack expansion whose
14836 parameter packs are of length zero. */
14839 else
14840 {
14844 else
14845 {
14848 }
14849 }
14855 complain);
14863 }
14866 {
14872 complain));
14873 }
14876 {
14880 integral_constant_expression_p);
14882 op0,
14885 }
14888 {
14889 tree function;
14894 tree ret;
14897 /* When we parsed the expression, we determined whether or
14898 not Koenig lookup should be performed. */
14901 {
14906 }
14908 {
14909 /* Do nothing; calling tsubst_copy_and_build on an identifier
14910 would incorrectly perform unqualified lookup again.
14912 Note that we can also have an IDENTIFIER_NODE if the earlier
14913 unqualified lookup found a member function; in that case
14914 koenig_p will be false and we do want to do the lookup
14915 again to find the instantiated member function.
14917 FIXME but doing that causes c++/15272, so we need to stop
14918 using IDENTIFIER_NODE in that situation. */
14920 }
14921 else
14922 {
14924 {
14930 }
14931 else
14936 /* Avoid error about taking the address of a constructor. */
14940 in_decl,
14942 integral_constant_expression_p);
14946 }
14951 {
14956 else
14957 {
14958 /* Expand the pack expansion and push each entry onto
14959 CALL_ARGS. */
14962 {
14967 {
14972 }
14973 }
14974 else
14975 {
14976 /* A partial substitution. Add one entry. */
14978 }
14979 }
14980 }
14982 /* We do not perform argument-dependent lookup if normal
14983 lookup finds a non-function, in accordance with the
14984 expected resolution of DR 218. */
14987 /* If lookup found a member function, the Koenig lookup is
14988 not appropriate, even if an unqualified-name was used
14989 to denote the function. */
14992 /* Only do this when substitution turns a dependent call
14993 into a non-dependent call. */
15000 {
15002 {
15003 /* For backwards compatibility and good diagnostics, try
15004 the unqualified lookup again if we aren't in SFINAE
15005 context. */
15006 tree unq = (tsubst_copy_and_build
15008 integral_constant_expression_p));
15013 {
15022 "%qD was not declared in this scope, "
15023 "and no declarations were found by "
15024 "argument-dependent lookup at the point "
15026 {
15030 {
15032 input_location);
15034 "declarations in dependent base %qT are "
15040 else
15044 }
15045 else
15048 }
15050 }
15051 }
15053 {
15058 }
15059 }
15061 /* Remember that there was a reference to this entity. */
15065 /* Put back tf_decltype for the actual call. */
15070 complain);
15072 {
15087 complain);
15088 else
15089 ret = (build_new_method_call
15094 complain));
15095 }
15096 else
15099 koenig_p,
15100 complain);
15105 }
15108 {
15113 {
15115 {
15120 }
15121 else
15122 {
15127 }
15128 }
15129 else
15130 {
15133 }
15137 }
15140 {
15145 input_location));
15146 }
15149 {
15157 {
15158 /* We have pack expansions, so expand those and
15159 create a new list out of it. */
15162 tree chain;
15165 /* Expand the argument expressions. */
15173 /* Build the rest of the list. */
15178 /* Determine the number of arguments. */
15180 {
15183 }
15186 else
15187 {
15188 /* Since we only performed a partial substitution into
15189 the argument pack, we only RETURN (a single list
15190 node. */
15197 }
15199 /* Convert the argument vectors into a TREE_LIST */
15202 {
15203 /* Grab the Ith values. */
15204 i--;
15207 value
15211 /* Build the list (backwards). */
15213 }
15216 }
15232 }
15235 {
15236 tree object;
15237 tree object_type;
15238 tree member;
15239 tree r;
15243 /* Remember that there was a reference to this entity. */
15253 else
15261 {
15263 {
15268 {
15271 }
15273 {
15278 }
15279 }
15280 }
15283 {
15284 /* Lookup the template functions now that we know what the
15285 scope is. */
15293 {
15296 args);
15297 member = (adjust_result_of_qualified_name_lookup
15299 object_type));
15300 }
15301 else
15302 {
15304 input_location);
15306 }
15307 }
15311 {
15313 {
15317 else
15320 }
15322 }
15324 {
15329 }
15333 complain);
15337 }
15344 {
15352 tree r;
15357 /* digest_init will do the wrong thing if we let it. */
15361 /* We do not want to process the index of aggregate
15362 initializers as they are identifier nodes which will be
15363 looked up by digest_init. */
15369 {
15371 /* An identifier index is looked up in the type
15372 being initialized, not the current scope. */
15377 {
15378 /* Substitute into the pack expansion. */
15380 in_decl);
15384 ;
15386 /* Just move the argument into place. */
15388 else
15389 {
15390 /* Update the length of the final CONSTRUCTOR
15391 arguments vector, and note that we will need to
15392 copy.*/
15395 }
15396 }
15397 else
15399 }
15402 {
15407 {
15409 {
15414 }
15415 else
15417 }
15418 }
15428 }
15431 {
15434 {
15437 }
15438 else
15439 {
15442 }
15443 }
15449 {
15450 /* We don't build decls for an instantiation of a
15451 variadic capture proxy, we instantiate the elements
15452 when needed. */
15455 }
15456 /* Fall through */
15459 {
15461 /* ??? We're doing a subset of finish_id_expression here. */
15463 && !processing_template_decl
15464 && !cp_unevaluated_operand
15467 {
15469 /* Replace an evaluated use of the thread_local variable with
15470 a call to its wrapper. */
15472 }
15477 /* If the original type was a reference, we'll be wrapped in
15478 the appropriate INDIRECT_REF. */
15481 }
15484 {
15488 }
15495 {
15506 }
15509 {
15515 integral_constant_expression_p);
15519 /* If the resulting list of expression statement is empty,
15520 fold it further into void_node. */
15525 }
15528 {
15542 /* For a function scope, we want to use tsubst so that we don't
15543 complain about referring to an auto function before its return
15544 type has been deduced. Otherwise, we want to use tsubst_copy so
15545 that we look up the existing field/parameter/variable rather
15546 than build a new one. */
15551 {
15552 /* Look up the parameter we want directly, as tsubst_copy
15553 doesn't do what we need. */
15559 /* FIXME Work around the parm not having DECL_CONTEXT set. */
15562 }
15563 else
15572 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
15574 /* Now that we know visibility, instantiate the type so we have a
15575 declaration of the op() for later calls to lambda_function. */
15581 }
15584 /* We can get here for a constant initializer of non-dependent type.
15585 FIXME stop folding in cp_parser_initializer_clause. */
15586 {
15588 complain);
15590 }
15594 integral_constant_expression_p));
15600 {
15605 complain));
15606 }
15609 /* Handle Objective-C++ constructs, if appropriate. */
15610 {
15611 tree subst
15616 }
15618 }
15620 #undef RECUR
15621 #undef RETURN
15622 out:
15625 }
15627 /* Verify that the instantiated ARGS are valid. For type arguments,
15628 make sure that the type's linkage is ok. For non-type arguments,
15629 make sure they are constants if they are integral or enumerations.
15630 Emit an error under control of COMPLAIN, and return TRUE on error. */
15632 static bool
15634 {
15638 {
15648 }
15650 {
15651 /* [basic.link]: A name with no linkage (notably, the name
15652 of a class or enumeration declared in a local scope)
15653 shall not be used to declare an entity with linkage.
15654 This implies that names with no linkage cannot be used as
15655 template arguments
15657 DR 757 relaxes this restriction for C++0x. */
15662 {
15663 /* DR 488 makes use of a type with no linkage cause
15664 type deduction to fail. */
15666 {
15669 else
15672 }
15674 }
15675 /* In order to avoid all sorts of complications, we do not
15676 allow variably-modified types as template arguments. */
15678 {
15682 }
15683 }
15684 /* Class template and alias template arguments should be OK. */
15686 ;
15687 /* A non-type argument of integral or enumerated type must be a
15688 constant. */
15692 {
15696 }
15698 }
15700 static bool
15702 {
15707 {
15710 }
15714 }
15716 /* We're out of SFINAE context now, so generate diagnostics for the access
15717 errors we saw earlier when instantiating D from TMPL and ARGS. */
15719 static void
15721 {
15733 }
15735 /* Instantiate the indicated variable, function, or alias template TMPL with
15736 the template arguments in TARG_PTR. */
15738 static tree
15740 {
15742 tree fndecl;
15743 tree gen_tmpl;
15744 tree spec;
15752 /* If this function is a clone, handle it specially. */
15754 {
15755 tree spec;
15756 tree clone;
15758 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
15759 DECL_CLONED_FUNCTION. */
15765 /* Look for the clone. */
15769 /* We should always have found the clone by now. */
15772 }
15777 /* Check to see if we already have this specialization. */
15780 /* The TMPL is a partial instantiation. To get a full set of
15781 arguments we must add the arguments used to perform the
15782 partial instantiation. */
15784 targ_ptr);
15786 /* It would be nice to avoid hashing here and then again in tsubst_decl,
15787 but it doesn't seem to be on the hot path. */
15796 {
15798 {
15802 }
15804 }
15807 complain))
15810 /* We are building a FUNCTION_DECL, during which the access of its
15811 parameters and return types have to be checked. However this
15812 FUNCTION_DECL which is the desired context for access checking
15813 is not built yet. We solve this chicken-and-egg problem by
15814 deferring all checks until we have the FUNCTION_DECL. */
15817 /* Instantiation of the function happens in the context of the function
15818 template, not the context of the overload resolution we're doing. */
15820 /* If there are dependent arguments, e.g. because we're doing partial
15821 ordering, make sure processing_template_decl stays set. */
15825 {
15829 }
15830 /* Substitute template parameters to obtain the specialization. */
15838 {
15841 }
15843 /* The DECL_TI_TEMPLATE should always be the immediate parent
15844 template, not the most general template. */
15847 /* Now we know the specialization, compute access previously
15848 deferred. */
15855 /* If we've just instantiated the main entry point for a function,
15856 instantiate all the alternate entry points as well. We do this
15857 by cloning the instantiation of the main entry point, not by
15858 instantiating the template clones. */
15863 {
15865 {
15866 /* Remember to reinstantiate when we're out of SFINAE so the user
15867 can see the errors. */
15869 }
15871 }
15873 }
15875 /* Wrapper for instantiate_template_1. */
15877 tree
15879 {
15880 tree ret;
15885 }
15887 /* Instantiate the alias template TMPL with ARGS. Also push a template
15888 instantiation level, which instantiate_template doesn't do because
15889 functions and variables have sufficient context established by the
15890 callers. */
15892 static tree
15894 {
15901 {
15904 }
15906 args =
15914 /* We can't free this if a pending_template entry or last_error_tinst_level
15915 is pointing at it. */
15921 }
15923 /* PARM is a template parameter pack for FN. Returns true iff
15924 PARM is used in a deducible way in the argument list of FN. */
15926 static bool
15928 {
15931 {
15933 tree packs;
15939 {
15940 /* The template parameter pack is used in a function parameter
15941 pack. If this is the end of the parameter list, the
15942 template parameter pack is deducible. */
15945 else
15946 /* Otherwise, not. Well, it could be deduced from
15947 a non-pack parameter, but doing so would end up with
15948 a deduction mismatch, so don't bother. */
15950 }
15951 }
15952 /* The template parameter pack isn't used in any function parameter
15953 packs, but it might be used deeper, e.g. tuple<Args...>. */
15955 }
15957 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
15958 NARGS elements of the arguments that are being used when calling
15959 it. TARGS is a vector into which the deduced template arguments
15960 are placed.
15962 Returns either a FUNCTION_DECL for the matching specialization of FN or
15963 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
15964 true, diagnostics will be printed to explain why it failed.
15966 If FN is a conversion operator, or we are trying to produce a specific
15967 specialization, RETURN_TYPE is the return type desired.
15969 The EXPLICIT_TARGS are explicit template arguments provided via a
15970 template-id.
15972 The parameter STRICT is one of:
15974 DEDUCE_CALL:
15975 We are deducing arguments for a function call, as in
15976 [temp.deduct.call].
15978 DEDUCE_CONV:
15979 We are deducing arguments for a conversion function, as in
15980 [temp.deduct.conv].
15982 DEDUCE_EXACT:
15983 We are deducing arguments when doing an explicit instantiation
15984 as in [temp.explicit], when determining an explicit specialization
15985 as in [temp.expl.spec], or when taking the address of a function
15986 template, as in [temp.deduct.funcaddr]. */
15988 tree
15990 tree explicit_targs,
15991 tree targs,
15994 tree return_type,
15995 unification_kind_t strict,
15999 {
16000 tree parms;
16001 tree fntype;
16009 tree tinst;
16015 /* In C++0x, it's possible to have a function template whose type depends
16016 on itself recursively. This is most obvious with decltype, but can also
16017 occur with enumeration scope (c++/48969). So we need to catch infinite
16018 recursion and reject the substitution at deduction time; this function
16019 will return error_mark_node for any repeated substitution.
16021 This also catches excessive recursion such as when f<N> depends on
16022 f<N-1> across all integers, and returns error_mark_node for all the
16023 substitutions back up to the initial one.
16025 This is, of course, not reentrant. */
16035 {
16036 /* [temp.deduct]
16038 The specified template arguments must match the template
16039 parameters in kind (i.e., type, nontype, template), and there
16040 must not be more arguments than there are parameters;
16041 otherwise type deduction fails.
16043 Nontype arguments must match the types of the corresponding
16044 nontype template parameters, or must be convertible to the
16045 types of the corresponding nontype parameters as specified in
16046 _temp.arg.nontype_, otherwise type deduction fails.
16048 All references in the function type of the function template
16049 to the corresponding template parameters are replaced by the
16050 specified template argument values. If a substitution in a
16051 template parameter or in the function type of the function
16052 template results in an invalid type, type deduction fails. */
16057 /* Adjust any explicit template arguments before entering the
16058 substitution context. */
16059 explicit_targs
16061 complain,
16067 /* Substitute the explicit args into the function type. This is
16068 necessary so that, for instance, explicitly declared function
16069 arguments can match null pointed constants. If we were given
16070 an incomplete set of explicit args, we must not do semantic
16071 processing during substitution as we could create partial
16072 instantiations. */
16074 {
16079 /* Dig out the actual parm. */
16082 {
16085 }
16087 {
16090 }
16093 /* No explicit argument for this template parameter. */
16097 {
16098 /* Mark the argument pack as "incomplete". We could
16099 still deduce more arguments during unification.
16100 We remove this mark in type_unification_real. */
16102 {
16106 }
16108 /* We have some incomplete argument packs. */
16110 }
16111 }
16115 {
16118 }
16121 /* Ignore any access checks; we'll see them again in
16122 instantiate_template and they might have the wrong
16123 access path at this point. */
16135 /* Place the explicitly specified arguments in TARGS. */
16138 }
16140 /* Never do unification on the 'this' parameter. */
16144 {
16153 }
16155 /* We allow incomplete unification without an error message here
16156 because the standard doesn't seem to explicitly prohibit it. Our
16157 callers must be ready to deal with unification failures in any
16158 event. */
16161 /* If we aren't explaining yet, push tinst context so we can see where
16162 any errors (e.g. from class instantiations triggered by instantiation
16163 of default template arguments) come from. If we are explaining, this
16164 context is redundant. */
16166 {
16169 }
16171 /* type_unification_real will pass back any access checks from default
16172 template argument substitution. */
16184 /* Now that we have bindings for all of the template arguments,
16185 ensure that the arguments deduced for the template template
16186 parameters have compatible template parameter lists. We cannot
16187 check this property before we have deduced all template
16188 arguments, because the template parameter types of a template
16189 template parameter might depend on prior template parameters
16190 deduced after the template template parameter. The following
16191 ill-formed example illustrates this issue:
16193 template<typename T, template<T> class C> void f(C<5>, T);
16195 template<int N> struct X {};
16197 void g() {
16198 f(X<5>(), 5l); // error: template argument deduction fails
16199 }
16201 The template parameter list of 'C' depends on the template type
16202 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
16203 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
16204 time that we deduce 'C'. */
16207 {
16210 }
16212 /* All is well so far. Now, check:
16214 [temp.deduct]
16216 When all template arguments have been deduced, all uses of
16217 template parameters in nondeduced contexts are replaced with
16218 the corresponding deduced argument values. If the
16219 substitution results in an invalid type, as described above,
16220 type deduction fails. */
16223 {
16226 }
16228 /* Also collect access checks from the instantiation. */
16241 /* Now perform any access checks encountered during substitution. */
16248 /* If we're looking for an exact match, check that what we got
16249 is indeed an exact match. It might not be if some template
16250 parameters are used in non-deduced contexts. But don't check
16251 for an exact match if we have dependent template arguments;
16252 in that case we're doing partial ordering, and we already know
16253 that we have two candidates that will provide the actual type. */
16255 {
16259 tree sarg
16265 {
16269 }
16270 }
16274 fail:
16277 {
16279 /* Reset once we're all the way out. */
16281 }
16283 /* We can't free this if a pending_template entry or last_error_tinst_level
16284 is pointing at it. */
16290 }
16292 /* Adjust types before performing type deduction, as described in
16293 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
16294 sections are symmetric. PARM is the type of a function parameter
16295 or the return type of the conversion function. ARG is the type of
16296 the argument passed to the call, or the type of the value
16297 initialized with the result of the conversion function.
16298 ARG_EXPR is the original argument expression, which may be null. */
16300 static int
16304 tree arg_expr)
16305 {
16309 {
16314 {
16315 /* Swap PARM and ARG throughout the remainder of this
16316 function; the handling is precisely symmetric since PARM
16317 will initialize ARG rather than vice versa. */
16322 }
16325 /* Core issue #873: Do the DR606 thing (see below) for these cases,
16326 too, but here handle it by stripping the reference from PARM
16327 rather than by adding it to ARG. */
16335 /* Nothing else to do in this case. */
16340 }
16343 {
16344 /* [temp.deduct.call]
16346 If P is not a reference type:
16348 --If A is an array type, the pointer type produced by the
16349 array-to-pointer standard conversion (_conv.array_) is
16350 used in place of A for type deduction; otherwise,
16352 --If A is a function type, the pointer type produced by
16353 the function-to-pointer standard conversion
16354 (_conv.func_) is used in place of A for type deduction;
16355 otherwise,
16357 --If A is a cv-qualified type, the top level
16358 cv-qualifiers of A's type are ignored for type
16359 deduction. */
16364 else
16366 }
16368 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
16369 of the form T&&, where T is a template parameter, and the argument
16370 is an lvalue, T is deduced as A& */
16376 /* try_one_overload doesn't provide an arg_expr, but
16377 functions are always lvalues. */
16381 /* [temp.deduct.call]
16383 If P is a cv-qualified type, the top level cv-qualifiers
16384 of P's type are ignored for type deduction. If P is a
16385 reference type, the type referred to by P is used for
16386 type deduction. */
16389 {
16392 }
16394 /* DR 322. For conversion deduction, remove a reference type on parm
16395 too (which has been swapped into ARG). */
16400 }
16402 /* Subroutine of unify_one_argument. PARM is a function parameter of a
16403 template which does contain any deducible template parameters; check if
16404 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
16405 unify_one_argument. */
16407 static int
16410 {
16411 tree type;
16415 else
16422 {
16426 }
16428 {
16433 }
16437 else
16439 }
16443 /* Returns true iff the expression EXPR is one from which a template
16444 argument can be deduced. In other words, if it's an undecorated
16445 use of a template non-type parameter. */
16447 static bool
16449 {
16451 }
16453 /* Returns true iff the array domain DOMAIN uses a template parameter in a
16454 deducible way; that is, if it has a max value of <PARM> - 1. */
16456 static bool
16458 {
16467 }
16469 /* Returns true iff the template arguments ARGS use a template parameter
16470 in a deducible way. */
16472 static bool
16474 {
16476 {
16481 else
16482 {
16489 else
16491 }
16494 }
16496 }
16498 /* Returns true iff TYPE contains any deducible references to template
16499 parameters, as per 14.8.2.5. */
16501 static bool
16503 {
16507 /* T
16508 cv-list T
16509 TT<T>
16510 TT<i>
16511 TT<> */
16516 /* T*
16517 T&
16518 T&& */
16522 /* T[integer-constant ]
16523 type [i] */
16528 /* T type ::*
16529 type T::*
16530 T T::*
16531 T (type ::*)()
16532 type (T::*)()
16533 type (type ::*)(T)
16534 type (T::*)(T)
16535 T (type ::*)(T)
16536 T (T::*)()
16537 T (T::*)(T) */
16540 || (uses_deducible_template_parms
16543 /* template-name <T> (where template-name refers to a class template)
16544 template-name <i> (where template-name refers to a class template) */
16551 /* type (T)
16552 T()
16553 T(T) */
16556 {
16565 }
16568 }
16570 /* Subroutine of type_unification_real and unify_pack_expansion to
16571 handle unification of a single P/A pair. Parameters are as
16572 for those functions. */
16574 static int
16578 {
16585 /* We can't deduce anything from this, but we might get all the
16586 template args from other function args. */
16589 /* Implicit conversions (Clause 4) will be performed on a function
16590 argument to convert it to the type of the corresponding function
16591 parameter if the parameter type contains no template-parameters that
16592 participate in template argument deduction. */
16594 /* For function parameters that contain no template-parameters at all,
16595 we have historically checked for convertibility in order to shortcut
16596 consideration of this candidate. */
16598 explain_p);
16601 /* For function parameters with only non-deducible template parameters,
16602 just return. */
16606 {
16608 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
16609 | UNIFY_ALLOW_MORE_CV_QUAL
16623 }
16625 /* We only do these transformations if this is the top-level
16626 parameter_type_list in a call or declaration matching; in other
16627 situations (nested function declarators, template argument lists) we
16628 won't be comparing a type to an expression, and we don't do any type
16629 adjustments. */
16631 {
16633 {
16636 {
16637 /* [temp.deduct.type] A template-argument can be
16638 deduced from a pointer to function or pointer
16639 to member function argument if the set of
16640 overloaded functions does not contain function
16641 templates and at most one of a set of
16642 overloaded functions provides a unique
16643 match. */
16650 }
16656 }
16658 arg_strict |=
16660 }
16661 else
16666 /* For deduction from an init-list we need the actual list. */
16670 }
16672 /* Most parms like fn_type_unification.
16674 If SUBR is 1, we're being called recursively (to unify the
16675 arguments of a function or method parameter of a function
16676 template).
16678 CHECKS is a pointer to a vector of access checks encountered while
16679 substituting default template arguments. */
16681 static int
16683 tree targs,
16684 tree xparms,
16688 unification_kind_t strict,
16692 {
16697 tree parms;
16706 /* Reset the number of non-defaulted template arguments contained
16707 in TARGS. */
16710 again:
16718 {
16723 /* For a function parameter pack that occurs at the end of the
16724 parameter-declaration-list, the type A of each remaining
16725 argument of the call is compared with the type P of the
16726 declarator-id of the function parameter pack. */
16732 /* For a function parameter pack that does not occur at the
16733 end of the parameter-declaration-list, the type of the
16734 parameter pack is a non-deduced context. */
16743 }
16748 {
16749 /* Unify the remaining arguments with the pack expansion type. */
16750 tree argvec;
16753 /* Allocate a TREE_VEC and copy in all of the arguments */
16758 /* Copy the parameter into parmvec. */
16764 /* Advance to the end of the list of parameters. */
16766 }
16768 /* Fail if we've reached the end of the parm list, and more args
16769 are present, and the parm list isn't variadic. */
16772 /* Fail if parms are left and they don't have default values and
16773 they aren't all deduced as empty packs (c++/57397). This is
16774 consistent with sufficient_parms_p. */
16777 {
16781 do
16782 {
16785 count++;
16787 }
16791 type_pack_p);
16792 }
16795 {
16796 tsubst_flags_t complain = (explain_p
16797 ? tf_warning_or_error
16801 {
16805 /* Clear the "incomplete" flags on all argument packs now so that
16806 substituting them into later default arguments works. */
16808 {
16811 }
16817 /* If this is an undeduced nontype parameter that depends on
16818 a type parameter, try another pass; its type may have been
16819 deduced from a later argument than the one from which
16820 this parameter can be deduced. */
16826 /* Core issue #226 (C++0x) [temp.deduct]:
16828 If a template argument has not been deduced, its
16829 default template argument, if any, is used.
16831 When we are in C++98 mode, TREE_PURPOSE will either
16832 be NULL_TREE or ERROR_MARK_NODE, so we do not need
16833 to explicitly check cxx_dialect here. */
16835 {
16850 else
16851 {
16853 /* The position of the first default template argument,
16854 is also the number of non-defaulted arguments in TARGS.
16855 Record that. */
16859 }
16860 }
16862 /* If the type parameter is a parameter pack, then it will
16863 be deduced to an empty parameter pack. */
16865 {
16866 tree arg;
16869 {
16873 }
16874 else
16881 }
16884 }
16885 }
16886 #ifdef ENABLE_CHECKING
16889 #endif
16892 }
16894 /* Subroutine of type_unification_real. Args are like the variables
16895 at the call site. ARG is an overloaded function (or template-id);
16896 we try deducing template args from each of the overloads, and if
16897 only one succeeds, we go with that. Modifies TARGS and returns
16898 true on success. */
16900 static bool
16902 tree targs,
16903 tree parm,
16904 tree arg,
16905 unification_kind_t strict,
16908 {
16915 {
16918 }
16919 else
16923 /* Handle `&x' where `x' is some static or non-static member
16924 function name. */
16930 /* Strip baselink information. */
16935 {
16936 /* If we got some explicit template args, we need to plug them into
16937 the affected templates before we try to unify, in case the
16938 explicit args will completely resolve the templates in question. */
16945 {
16958 {
16963 {
16966 }
16967 }
16970 }
16971 /* If no templates (or more than one) are fully resolved by the
16972 explicit arguments, this template-id is a non-deduced context; it
16973 could still be OK if we deduce all template arguments for the
16974 enclosing call through other arguments. */
16977 }
16980 /* If ARG is, for example, "(0, &f)" then its type will be unknown
16981 -- but the deduction does not succeed because the expression is
16982 not just the function on its own. */
16984 else
16990 {
16993 }
16995 /* [temp.deduct.type] A template-argument can be deduced from a pointer
16996 to function or pointer to member function argument if the set of
16997 overloaded functions does not contain function templates and at most
16998 one of a set of overloaded functions provides a unique match.
17000 So if we found multiple possibilities, we return success but don't
17001 deduce anything. */
17004 {
17008 {
17013 /* Don't forget explicit template arguments in a pack. */
17017 }
17018 }
17023 }
17025 /* Core DR 115: In contexts where deduction is done and fails, or in
17026 contexts where deduction is not done, if a template argument list is
17027 specified and it, along with any default template arguments, identifies
17028 a single function template specialization, then the template-id is an
17029 lvalue for the function template specialization. */
17031 tree
17033 {
17046 {
17049 }
17051 {
17054 }
17056 {
17059 }
17062 {
17066 /* If we got some explicit template args, we need to plug them into
17067 the affected templates before we try to unify, in case the
17068 explicit args will completely resolve the templates in question. */
17076 {
17089 {
17092 {
17095 }
17097 {
17100 }
17101 }
17102 }
17104 {
17112 {
17113 tree base
17116 }
17120 }
17122 /* There were no good options and at least one bad one, so let the
17123 user know what the problem is. */
17125 }
17127 }
17129 /* Subroutine of resolve_overloaded_unification; does deduction for a single
17130 overload. Fills TARGS with any deduced arguments, or error_mark_node if
17131 different overloads deduce different arguments for a given parm.
17132 ADDR_P is true if the expression for which deduction is being
17133 performed was of the form "& fn" rather than simply "fn".
17135 Returns 1 on success. */
17137 static int
17139 tree orig_targs,
17140 tree targs,
17141 tree parm,
17142 tree arg,
17143 unification_kind_t strict,
17147 {
17149 tree tempargs;
17155 /* [temp.deduct.type] A template-argument can be deduced from a pointer
17156 to function or pointer to member function argument if the set of
17157 overloaded functions does not contain function templates and at most
17158 one of a set of overloaded functions provides a unique match.
17160 So if this is a template, just return success. */
17172 /* We don't copy orig_targs for this because if we have already deduced
17173 some template args from previous args, unify would complain when we
17174 try to deduce a template parameter for the same argument, even though
17175 there isn't really a conflict. */
17182 /* First make sure we didn't deduce anything that conflicts with
17183 explicitly specified args. */
17185 {
17192 /* Since we're unifying against ourselves, we will fill in
17193 template args used in the function parm list with our own
17194 template parms. Discard them. */
17198 }
17201 {
17206 }
17209 }
17211 /* PARM is a template class (perhaps with unbound template
17212 parameters). ARG is a fully instantiated type. If ARG can be
17213 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
17214 TARGS are as for unify. */
17216 static tree
17219 {
17220 tree copy_of_targs;
17227 /* We need to make a new template argument vector for the call to
17228 unify. If we used TARGS, we'd clutter it up with the result of
17229 the attempted unification, even if this class didn't work out.
17230 We also don't want to commit ourselves to all the unifications
17231 we've already done, since unification is supposed to be done on
17232 an argument-by-argument basis. In other words, consider the
17233 following pathological case:
17235 template <int I, int J, int K>
17236 struct S {};
17238 template <int I, int J>
17239 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
17241 template <int I, int J, int K>
17242 void f(S<I, J, K>, S<I, I, I>);
17244 void g() {
17245 S<0, 0, 0> s0;
17246 S<0, 1, 2> s2;
17248 f(s0, s2);
17249 }
17251 Now, by the time we consider the unification involving `s2', we
17252 already know that we must have `f<0, 0, 0>'. But, even though
17253 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
17254 because there are two ways to unify base classes of S<0, 1, 2>
17255 with S<I, I, I>. If we kept the already deduced knowledge, we
17256 would reject the possibility I=1. */
17259 /* If unification failed, we're done. */
17265 }
17267 /* Given a template type PARM and a class type ARG, find the unique
17268 base type in ARG that is an instance of PARM. We do not examine
17269 ARG itself; only its base-classes. If there is not exactly one
17270 appropriate base class, return NULL_TREE. PARM may be the type of
17271 a partial specialization, as well as a plain template type. Used
17272 by unify. */
17274 static enum template_base_result
17277 {
17279 tree binfo;
17285 {
17286 /* The type could not be completed. */
17289 }
17291 /* Walk in inheritance graph order. The search order is not
17292 important, and this avoids multiple walks of virtual bases. */
17294 {
17299 {
17300 /* If there is more than one satisfactory baseclass, then:
17302 [temp.deduct.call]
17304 If they yield more than one possible deduced A, the type
17305 deduction fails.
17307 applies. */
17309 {
17312 }
17315 }
17316 }
17320 }
17322 /* Returns the level of DECL, which declares a template parameter. */
17324 static int
17326 {
17328 {
17338 }
17340 }
17342 /* Decide whether ARG can be unified with PARM, considering only the
17343 cv-qualifiers of each type, given STRICT as documented for unify.
17344 Returns nonzero iff the unification is OK on that basis. */
17346 static int
17348 {
17354 {
17355 /* Although a CVR qualifier is ignored when being applied to a
17356 substituted template parameter ([8.3.2]/1 for example), that
17357 does not allow us to unify "const T" with "int&" because both
17358 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
17359 It is ok when we're allowing additional CV qualifiers
17360 at the outer level [14.8.2.1]/3,1st bullet. */
17370 }
17381 }
17383 /* Determines the LEVEL and INDEX for the template parameter PARM. */
17384 void
17386 {
17390 {
17393 }
17394 else
17395 {
17398 }
17399 }
17401 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
17402 do { \
17403 if (unify (TP, TA, P, A, S, EP)) \
17404 return 1; \
17405 } while (0);
17407 /* Unifies the remaining arguments in PACKED_ARGS with the pack
17408 expansion at the end of PACKED_PARMS. Returns 0 if the type
17409 deduction succeeds, 1 otherwise. STRICT is the same as in
17410 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
17411 call argument list. We'll need to adjust the arguments to make them
17412 types. SUBR tells us if this is from a recursive call to
17413 type_unification_real, or for comparing two template argument
17414 lists. */
17416 static int
17420 {
17421 tree parm
17431 /* Determine the parameter packs we will be deducing from the
17432 pattern, and record their current deductions. */
17435 {
17439 /* Determine the index and level of this parameter pack. */
17442 /* Keep track of the parameter packs and their corresponding
17443 argument packs. */
17446 }
17448 /* Loop through all of the arguments that have not yet been
17449 unified and unify each with the pattern. */
17451 {
17452 tree parm;
17456 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
17457 or the element of its argument pack at the current index if
17458 this argument was explicitly specified. */
17460 {
17469 {
17472 }
17474 }
17476 /* If we had explicit template arguments, substitute them into the
17477 pattern before deduction. */
17479 {
17480 /* Some arguments might still be unspecified or dependent. */
17488 NULL_TREE);
17493 }
17494 else
17497 /* Unify the pattern with the current argument. */
17502 /* For each parameter pack, collect the deduced value. */
17504 {
17510 }
17511 }
17513 /* Verify that the results of unification with the parameter packs
17514 produce results consistent with what we've seen before, and make
17515 the deduced argument packs available. */
17517 {
17524 /* By default keep the original deduced argument pack.
17525 If necessary, more specific code is going to update the
17526 resulting deduced argument later down in this function. */
17530 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
17531 actually deduce anything. */
17539 {
17540 /* If we had fewer function args than explicit template args,
17541 just use the explicits. */
17546 }
17549 {
17550 tree result;
17551 /* Build the deduced *_ARGUMENT_PACK. */
17553 {
17558 }
17559 else
17564 /* Note the deduced argument packs for this parameter
17565 pack. */
17567 }
17571 {
17572 /* We only had the explicitly-provided arguments before, but
17573 now we have a complete set of arguments. */
17579 }
17580 else
17581 {
17587 /* Inconsistent unification of this parameter pack. */
17589 bad_old_arg,
17590 bad_new_arg);
17591 }
17592 }
17595 }
17597 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
17598 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
17599 parameters and return value are as for unify. */
17601 static int
17605 {
17606 tree parm_max;
17607 tree arg_max;
17611 /* Our representation of array types uses "N - 1" as the
17612 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
17613 not an integer constant. We cannot unify arbitrarily
17614 complex expressions, so we eliminate the MINUS_EXPRs
17615 here. */
17619 {
17622 }
17626 {
17627 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
17628 trying to unify the type of a variable with the type
17629 of a template parameter. For example:
17631 template <unsigned int N>
17632 void f (char (&) [N]);
17633 int g();
17634 void h(int i) {
17635 char a[g(i)];
17636 f(a);
17637 }
17639 Here, the type of the ARG will be "int [g(i)]", and
17640 may be a SAVE_EXPR, etc. */
17644 }
17646 /* If only one of the bounds used a MINUS_EXPR, compensate
17647 by adding one to the other bound. */
17650 integer_type_node,
17651 parm_max,
17652 integer_one_node);
17655 integer_type_node,
17656 arg_max,
17657 integer_one_node);
17661 }
17663 /* Deduce the value of template parameters. TPARMS is the (innermost)
17664 set of template parameters to a template. TARGS is the bindings
17665 for those template parameters, as determined thus far; TARGS may
17666 include template arguments for outer levels of template parameters
17667 as well. PARM is a parameter to a template function, or a
17668 subcomponent of that parameter; ARG is the corresponding argument.
17669 This function attempts to match PARM with ARG in a manner
17670 consistent with the existing assignments in TARGS. If more values
17671 are deduced, then TARGS is updated.
17673 Returns 0 if the type deduction succeeds, 1 otherwise. The
17674 parameter STRICT is a bitwise or of the following flags:
17676 UNIFY_ALLOW_NONE:
17677 Require an exact match between PARM and ARG.
17678 UNIFY_ALLOW_MORE_CV_QUAL:
17679 Allow the deduced ARG to be more cv-qualified (by qualification
17680 conversion) than ARG.
17681 UNIFY_ALLOW_LESS_CV_QUAL:
17682 Allow the deduced ARG to be less cv-qualified than ARG.
17683 UNIFY_ALLOW_DERIVED:
17684 Allow the deduced ARG to be a template base class of ARG,
17685 or a pointer to a template base class of the type pointed to by
17686 ARG.
17687 UNIFY_ALLOW_INTEGER:
17688 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
17689 case for more information.
17690 UNIFY_ALLOW_OUTER_LEVEL:
17691 This is the outermost level of a deduction. Used to determine validity
17692 of qualification conversions. A valid qualification conversion must
17693 have const qualified pointers leading up to the inner type which
17694 requires additional CV quals, except at the outer level, where const
17695 is not required [conv.qual]. It would be normal to set this flag in
17696 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
17697 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
17698 This is the outermost level of a deduction, and PARM can be more CV
17699 qualified at this point.
17700 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
17701 This is the outermost level of a deduction, and PARM can be less CV
17702 qualified at this point. */
17704 static int
17707 {
17709 tree targ;
17710 tree tparm;
17713 /* I don't think this will do the right thing with respect to types.
17714 But the only case I've seen it in so far has been array bounds, where
17715 signedness is the only information lost, and I think that will be
17716 okay. */
17724 /* We can't deduce anything from this, but we might get all the
17725 template args from other function args. */
17728 /* If PARM uses template parameters, then we can't bail out here,
17729 even if ARG == PARM, since we won't record unifications for the
17730 template parameters. We might need them if we're trying to
17731 figure out which of two things is more specialized. */
17735 /* Handle init lists early, so the rest of the function can assume
17736 we're dealing with a type. */
17738 {
17743 /* Replace T with std::initializer_list<T> for deduction. */
17750 /* We can only deduce from an initializer list argument if the
17751 parameter is std::initializer_list or an array; otherwise this
17752 is a non-deduced context. */
17757 else
17761 {
17768 {
17770 /* It should only be possible to get here for a call. */
17772 elt_strict |= maybe_adjust_types_for_deduction
17775 }
17778 explain_p);
17779 }
17783 {
17784 /* Also deduce from the length of the initializer list. */
17791 }
17793 /* If the std::initializer_list<T> deduction worked, replace the
17794 deduced A with std::initializer_list<A>. */
17796 {
17801 }
17803 }
17805 /* Immediately reject some pairs that won't unify because of
17806 cv-qualification mismatches. */
17809 /* It is the elements of the array which hold the cv quals of an array
17810 type, and the elements might be template type parms. We'll check
17811 when we recurse. */
17813 /* We check the cv-qualifiers when unifying with template type
17814 parameters below. We want to allow ARG `const T' to unify with
17815 PARM `T' for example, when computing which of two templates
17816 is more specialized, for example. */
17830 {
17834 /* In a type which contains a nested-name-specifier, template
17835 argument values cannot be deduced for template parameters used
17836 within the nested-name-specifier. */
17848 /* The PARM is not one we're trying to unify. Just check
17849 to see if it matches ARG. */
17850 {
17855 else
17857 }
17864 /* Check for mixed types and values. */
17872 {
17873 /* ARG must be constructed from a template class or a template
17874 template parameter. */
17878 {
17880 /* An alias template name is never deduced. */
17885 tree parm_parms
17886 = DECL_INNERMOST_TEMPLATE_PARMS
17891 /* The resolution to DR150 makes clear that default
17892 arguments for an N-argument may not be used to bind T
17893 to a template template parameter with fewer than N
17894 parameters. It is not safe to permit the binding of
17895 default arguments as an extension, as that may change
17896 the meaning of a conforming program. Consider:
17898 struct Dense { static const unsigned int dim = 1; };
17900 template <template <typename> class View,
17901 typename Block>
17902 void operator+(float, View<Block> const&);
17904 template <typename Block,
17905 unsigned int Dim = Block::dim>
17906 struct Lvalue_proxy { operator float() const; };
17908 void
17909 test_1d (void) {
17910 Lvalue_proxy<Dense> p;
17911 float b;
17912 b + p;
17913 }
17915 Here, if Lvalue_proxy is permitted to bind to View, then
17916 the global operator+ will be used; if they are not, the
17917 Lvalue_proxy will be converted to float. */
17919 full_argvec,
17921 (explain_p
17922 ? tf_warning_or_error
17929 /* Deduce arguments T, i from TT<T> or TT<i>.
17930 We check each element of PARMVEC and ARGVEC individually
17931 rather than the whole TREE_VEC since they can have
17932 different number of elements. */
17939 /* Check if the parameters end in a pack, making them
17940 variadic. */
17946 /* If the template argument list of P contains a pack
17947 expansion that is not the last template argument, the
17948 entire template argument list is a non-deduced
17949 context. */
17958 {
17963 }
17968 DEDUCE_EXACT,
17971 }
17974 /* Fall through to deduce template name. */
17975 }
17979 {
17980 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
17982 /* Simple cases: Value already set, does match or doesn't. */
17987 }
17988 else
17989 {
17990 /* If PARM is `const T' and ARG is only `int', we don't have
17991 a match unless we are allowing additional qualification.
17992 If ARG is `const int' and PARM is just `T' that's OK;
17993 that binds `const int' to `T'. */
17998 /* Consider the case where ARG is `const volatile int' and
17999 PARM is `const T'. Then, T should be `volatile int'. */
18000 arg = cp_build_qualified_type_real
18005 /* Simple cases: Value already set, does match or doesn't. */
18011 /* Make sure that ARG is not a variable-sized array. (Note
18012 that were talking about variable-sized arrays (like
18013 `int[n]'), rather than arrays of unknown size (like
18014 `int[]').) We'll get very confused by such a type since
18015 the bound of the array is not constant, and therefore
18016 not mangleable. Besides, such types are not allowed in
18017 ISO C++, so we can do as we please here. We do allow
18018 them for 'auto' deduction, since that isn't ABI-exposed. */
18022 /* Strip typedefs as in convert_template_argument. */
18024 }
18026 /* If ARG is a parameter pack or an expansion, we cannot unify
18027 against it unless PARM is also a parameter pack. */
18032 /* If the argument deduction results is a METHOD_TYPE,
18033 then there is a problem.
18034 METHOD_TYPE doesn't map to any real C++ type the result of
18035 the deduction can not be of that type. */
18049 {
18050 /* The PARM is not one we're trying to unify. Just check
18051 to see if it matches ARG. */
18057 }
18063 {
18068 }
18070 /* [temp.deduct.type] If, in the declaration of a function template
18071 with a non-type template-parameter, the non-type
18072 template-parameter is used in an expression in the function
18073 parameter-list and, if the corresponding template-argument is
18074 deduced, the template-argument type shall match the type of the
18075 template-parameter exactly, except that a template-argument
18076 deduced from an array bound may be of any integral type.
18077 The non-type parameter might use already deduced type parameters. */
18080 /* Template-parameter dependent expression. Just accept it for now.
18081 It will later be processed in convert_template_argument. */
18082 ;
18087 /* Convert the ARG to the type of PARM; the deduced non-type
18088 template argument must exactly match the types of the
18089 corresponding parameter. */
18092 /* We haven't deduced the type of this parameter yet. Try again
18093 later. */
18095 else
18098 /* If ARG is a parameter pack or an expansion, we cannot unify
18099 against it unless PARM is also a parameter pack. */
18109 {
18110 /* A pointer-to-member constant can be unified only with
18111 another constant. */
18115 /* Just unify the class member. It would be useless (and possibly
18116 wrong, depending on the strict flags) to unify also
18117 PTRMEM_CST_CLASS, because we want to be sure that both parm and
18118 arg refer to the same variable, even if through different
18119 classes. For instance:
18121 struct A { int x; };
18122 struct B : A { };
18124 Unification of &A::x and &B::x must succeed. */
18127 }
18130 {
18134 /* [temp.deduct.call]
18136 A can be another pointer or pointer to member type that can
18137 be converted to the deduced A via a qualification
18138 conversion (_conv.qual_).
18140 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
18141 This will allow for additional cv-qualification of the
18142 pointed-to types if appropriate. */
18145 /* The derived-to-base conversion only persists through one
18146 level of pointers. */
18151 }
18183 /* We have already checked cv-qualification at the top of the
18184 function. */
18188 /* As far as unification is concerned, this wins. Later checks
18189 will invalidate it if necessary. */
18192 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
18193 /* Type INTEGER_CST can come from ordinary constant template args. */
18205 {
18215 /* Check for pack expansions in the parameters. */
18217 {
18219 {
18221 /* We can unify against something with a trailing
18222 parameter pack. */
18224 else
18225 /* [temp.deduct.type]/9: If the template argument list of
18226 P contains a pack expansion that is not the last
18227 template argument, the entire template argument list
18228 is a non-deduced context. */
18230 }
18231 }
18233 /* If we don't have enough arguments to satisfy the parameters
18234 (not counting the pack expression at the end), or we have
18235 too many arguments for a parameter list that doesn't end in
18236 a pack expression, we can't unify. */
18242 /* Unify all of the parameters that precede the (optional)
18243 pack expression. */
18245 {
18250 }
18253 DEDUCE_EXACT,
18256 }
18264 {
18272 }
18277 {
18281 {
18282 /* First, we try to unify the PARM and ARG directly. */
18287 {
18288 /* Fallback to the special case allowed in
18289 [temp.deduct.call]:
18291 If P is a class, and P has the form
18292 template-id, then A can be a derived class of
18293 the deduced A. Likewise, if P is a pointer to
18294 a class of the form template-id, A can be a
18295 pointer to a derived class pointed to by the
18296 deduced A. */
18303 }
18304 }
18308 /* Perhaps PARM is something like S<U> and ARG is S<int>.
18309 Then, we should unify `int' and `U'. */
18311 else
18312 /* There's no chance of unification succeeding. */
18317 }
18324 {
18327 tree a;
18333 /* CV qualifications for methods can never be deduced, they must
18334 match exactly. We need to check them explicitly here,
18335 because type_unification_real treats them as any other
18336 cv-qualified parameter. */
18338 && (!check_cv_quals_for_unify
18358 }
18361 /* Unify a pointer to member with a pointer to member function, which
18362 deduces the type of the member as a function type. */
18364 {
18365 /* Check top-level cv qualifiers */
18373 /* Determine the type of the function we are unifying against. */
18377 }
18396 /* Matched cases are handled by the ARG == PARM test above. */
18400 /* A non-type template parameter that is a variable should be a
18401 an integral constant, in which case, it whould have been
18402 folded into its (constant) value. So we should not be getting
18403 a variable here. */
18414 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
18415 or UNDERLYING_TYPE nodes. */
18419 /* Unification fails if we hit an error node. */
18426 /* FALLTHRU */
18429 /* An unresolved overload is a nondeduced context. */
18434 /* We must be looking at an expression. This can happen with
18435 something like:
18437 template <int I>
18438 void foo(S<I>, S<I + 2>);
18440 This is a "nondeduced context":
18442 [deduct.type]
18444 The nondeduced contexts are:
18446 --A type that is a template-id in which one or more of
18447 the template-arguments is an expression that references
18448 a template-parameter.
18450 In these cases, we assume deduction succeeded, but don't
18451 actually infer any unifications. */
18456 else
18458 }
18459 }
18460 #undef RECUR_AND_CHECK_FAILURE
18461 \f
18462 /* Note that DECL can be defined in this translation unit, if
18463 required. */
18465 static void
18467 {
18468 tree clone;
18472 }
18474 /* Called if RESULT is explicitly instantiated, or is a member of an
18475 explicitly instantiated class. */
18477 void
18479 {
18482 /* If this entity has already been written out, it's too late to
18483 make any modifications. */
18487 /* For anonymous namespace we don't need to do anything. */
18489 {
18492 }
18495 /* The TREE_PUBLIC flag for function declarations will have been
18496 set correctly by tsubst. */
18499 /* This might have been set by an earlier implicit instantiation. */
18504 else
18505 {
18508 /* Always make artificials weak. */
18511 /* For WIN32 we also want to put explicit instantiations in
18512 linkonce sections. */
18515 }
18517 /* If EXTERN_P, then this function will not be emitted -- unless
18518 followed by an explicit instantiation, at which point its linkage
18519 will be adjusted. If !EXTERN_P, then this function will be
18520 emitted here. In neither circumstance do we want
18521 import_export_decl to adjust the linkage. */
18523 }
18525 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
18526 important template arguments. If any are missing, we check whether
18527 they're important by using error_mark_node for substituting into any
18528 args that were used for partial ordering (the ones between ARGS and END)
18529 and seeing if it bubbles up. */
18531 static bool
18533 {
18538 {
18541 }
18543 {
18547 }
18549 }
18551 /* Given two function templates PAT1 and PAT2, return:
18553 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
18554 -1 if PAT2 is more specialized than PAT1.
18555 0 if neither is more specialized.
18557 LEN indicates the number of parameters we should consider
18558 (defaulted parameters should not be considered).
18560 The 1998 std underspecified function template partial ordering, and
18561 DR214 addresses the issue. We take pairs of arguments, one from
18562 each of the templates, and deduce them against each other. One of
18563 the templates will be more specialized if all the *other*
18564 template's arguments deduce against its arguments and at least one
18565 of its arguments *does* *not* deduce against the other template's
18566 corresponding argument. Deduction is done as for class templates.
18567 The arguments used in deduction have reference and top level cv
18568 qualifiers removed. Iff both arguments were originally reference
18569 types *and* deduction succeeds in both directions, an lvalue reference
18570 wins against an rvalue reference and otherwise the template
18571 with the more cv-qualified argument wins for that pairing (if
18572 neither is more cv-qualified, they both are equal). Unlike regular
18573 deduction, after all the arguments have been deduced in this way,
18574 we do *not* verify the deduced template argument values can be
18575 substituted into non-deduced contexts.
18577 The logic can be a bit confusing here, because we look at deduce1 and
18578 targs1 to see if pat2 is at least as specialized, and vice versa; if we
18579 can find template arguments for pat1 to make arg1 look like arg2, that
18580 means that arg2 is at least as specialized as arg1. */
18582 int
18584 {
18597 /* Remove the this parameter from non-static member functions. If
18598 one is a non-static member function and the other is not a static
18599 member function, remove the first parameter from that function
18600 also. This situation occurs for operator functions where we
18601 locate both a member function (with this pointer) and non-member
18602 operator (with explicit first operand). */
18604 {
18609 }
18611 {
18614 {
18615 len--;
18617 }
18618 }
18620 /* If only one is a conversion operator, they are unordered. */
18624 /* Consider the return type for a conversion function */
18626 {
18629 len++;
18630 }
18632 processing_template_decl++;
18638 /* Stop when an ellipsis is seen. */
18640 {
18651 {
18652 /* When both arguments are pack expansions, we need only
18653 unify the patterns themselves. */
18657 /* This is the last comparison we need to do. */
18659 }
18662 {
18666 }
18669 {
18673 }
18679 {
18685 /* Setup the parameter vector, which contains only ARG1. */
18688 /* Setup the argument vector, which contains the remaining
18689 arguments. */
18698 /* We cannot deduce in the other direction, because ARG1 is
18699 a pack expansion but ARG2 is not. */
18701 }
18703 {
18709 /* Setup the parameter vector, which contains only ARG1. */
18712 /* Setup the argument vector, which contains the remaining
18713 arguments. */
18722 /* We cannot deduce in the other direction, because ARG2 is
18723 a pack expansion but ARG1 is not.*/
18725 }
18727 else
18728 {
18729 /* The normal case, where neither argument is a pack
18730 expansion. */
18737 }
18739 /* If we couldn't deduce arguments for tparms1 to make arg1 match
18740 arg2, then arg2 is not as specialized as arg1. */
18746 /* "If, for a given type, deduction succeeds in both directions
18747 (i.e., the types are identical after the transformations above)
18748 and both P and A were reference types (before being replaced with
18749 the type referred to above):
18750 - if the type from the argument template was an lvalue reference and
18751 the type from the parameter template was not, the argument type is
18752 considered to be more specialized than the other; otherwise,
18753 - if the type from the argument template is more cv-qualified
18754 than the type from the parameter template (as described above),
18755 the argument type is considered to be more specialized than the other;
18756 otherwise,
18757 - neither type is more specialized than the other." */
18760 {
18762 {
18765 else
18767 }
18769 {
18774 }
18775 }
18778 /* We've failed to deduce something in either direction.
18779 These must be unordered. */
18784 /* We have already processed all of the arguments in our
18785 handing of the pack expansion type. */
18790 }
18792 /* "In most cases, all template parameters must have values in order for
18793 deduction to succeed, but for partial ordering purposes a template
18794 parameter may remain without a value provided it is not used in the
18795 types being used for partial ordering."
18797 Thus, if we are missing any of the targs1 we need to substitute into
18798 origs1, then pat2 is not as specialized as pat1. This can happen when
18799 there is a nondeduced context. */
18805 processing_template_decl--;
18807 /* All things being equal, if the next argument is a pack expansion
18808 for one function but not for the other, prefer the
18809 non-variadic function. FIXME this is bogus; see c++/41958. */
18813 {
18816 }
18822 else
18824 }
18826 /* Determine which of two partial specializations of TMPL is more
18827 specialized.
18829 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
18830 to the first partial specialization. The TREE_VALUE is the
18831 innermost set of template parameters for the partial
18832 specialization. PAT2 is similar, but for the second template.
18834 Return 1 if the first partial specialization is more specialized;
18835 -1 if the second is more specialized; 0 if neither is more
18836 specialized.
18838 See [temp.class.order] for information about determining which of
18839 two templates is more specialized. */
18841 static int
18843 {
18844 tree targs;
18852 /* Just like what happens for functions, if we are ordering between
18853 different class template specializations, we may encounter dependent
18854 types in the arguments, and we need our dependency check functions
18855 to behave correctly. */
18861 {
18864 }
18870 {
18873 }
18876 /* In the case of a tie where at least one of the class templates
18877 has a parameter pack at the end, the template with the most
18878 non-packed parameters wins. */
18880 && any_deductions
18883 {
18889 /* We don't count the pack expansion at the end. */
18899 }
18902 }
18904 /* Return the template arguments that will produce the function signature
18905 DECL from the function template FN, with the explicit template
18906 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
18907 also match. Return NULL_TREE if no satisfactory arguments could be
18908 found. */
18910 static tree
18912 {
18916 tree decl_arg_types;
18919 tree arg;
18923 /* Never do unification on the 'this' parameter. */
18944 }
18946 /* Return the innermost template arguments that, when applied to a partial
18947 specialization of TMPL whose innermost template parameters are
18948 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
18949 ARGS.
18951 For example, suppose we have:
18953 template <class T, class U> struct S {};
18954 template <class T> struct S<T*, int> {};
18956 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
18957 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
18958 int}. The resulting vector will be {double}, indicating that `T'
18959 is bound to `double'. */
18961 static tree
18963 {
18965 tree deduced_args;
18966 tree innermost_deduced_args;
18970 {
18974 innermost_deduced_args);
18975 }
18976 else
18989 /* Verify that nondeduced template arguments agree with the type
18990 obtained from argument deduction.
18992 For example:
18994 struct A { typedef int X; };
18995 template <class T, class U> struct C {};
18996 template <class T> struct C<T, typename T::X> {};
18998 Then with the instantiation `C<A, int>', we can deduce that
18999 `T' is `A' but unify () does not check whether `typename T::X'
19000 is `int'. */
19006 /* We only need to check the innermost arguments; the other
19007 arguments will always agree. */
19012 /* Now that we have bindings for all of the template arguments,
19013 ensure that the arguments deduced for the template template
19014 parameters have compatible template parameter lists. See the use
19015 of template_template_parm_bindings_ok_p in fn_type_unification
19016 for more information. */
19021 }
19023 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
19024 Return the TREE_LIST node with the most specialized template, if
19025 any. If there is no most specialized template, the error_mark_node
19026 is returned.
19028 Note that this function does not look at, or modify, the
19029 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
19030 returned is one of the elements of INSTANTIATIONS, callers may
19031 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
19032 and retrieve it from the value returned. */
19034 tree
19036 {
19043 {
19049 fate--;
19054 fate++;
19059 {
19060 /* Equally specialized, move to next function. If there
19061 is no next function, nothing's most specialized. */
19066 }
19067 }
19070 /* Now verify that champ is better than everything earlier in the
19071 instantiation list. */
19079 {
19082 }
19084 processing_template_decl--;
19090 }
19092 /* If DECL is a specialization of some template, return the most
19093 general such template. Otherwise, returns NULL_TREE.
19095 For example, given:
19097 template <class T> struct S { template <class U> void f(U); };
19099 if TMPL is `template <class U> void S<int>::f(U)' this will return
19100 the full template. This function will not trace past partial
19101 specializations, however. For example, given in addition:
19103 template <class T> struct S<T*> { template <class U> void f(U); };
19105 if TMPL is `template <class U> void S<int*>::f(U)' this will return
19106 `template <class T> template <class U> S<T*>::f(U)'. */
19108 tree
19110 {
19112 {
19115 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
19116 template friend, or a FIELD_DECL for a capture pack. */
19119 }
19121 /* Look for more and more general templates. */
19123 {
19124 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
19125 (See cp-tree.h for details.) */
19133 /* Stop if we run into an explicitly specialized class template. */
19140 }
19143 }
19145 /* Return the most specialized of the class template partial
19146 specializations which can produce TYPE, a specialization of some class
19147 template. The value returned is actually a TREE_LIST; the TREE_TYPE is
19148 a _TYPE node corresponding to the partial specialization, while the
19149 TREE_PURPOSE is the set of template arguments that must be
19150 substituted into the TREE_TYPE in order to generate TYPE.
19152 If the choice of partial specialization is ambiguous, a diagnostic
19153 is issued, and the error_mark_node is returned. If there are no
19154 partial specializations matching TYPE, then NULL_TREE is
19155 returned, indicating that the primary template should be used. */
19157 static tree
19159 {
19161 tree t;
19162 tree champ;
19171 /* For determining which partial specialization to use, only the
19172 innermost args are interesting. */
19174 {
19177 }
19180 {
19181 tree partial_spec_args;
19182 tree spec_args;
19191 {
19192 /* Discard the outer levels of args, and then substitute in the
19193 template args from the enclosing class. */
19195 partial_spec_args = tsubst_template_args
19198 /* And the same for the partial specialization TEMPLATE_DECL. */
19200 }
19202 partial_spec_args =
19204 partial_spec_args,
19218 partial_spec_args,
19219 args);
19221 {
19226 }
19227 }
19237 {
19240 ;
19241 else
19242 {
19244 {
19247 {
19250 }
19251 }
19253 }
19254 }
19258 {
19261 {
19264 }
19265 }
19268 {
19276 {
19279 }
19282 }
19285 }
19287 /* Explicitly instantiate DECL. */
19289 void
19291 {
19296 /* An error occurred, for which grokdeclarator has already issued
19297 an appropriate message. */
19300 {
19303 }
19309 {
19310 /* There is an asymmetry here in the way VAR_DECLs and
19311 FUNCTION_DECLs are handled by grokdeclarator. In the case of
19312 the latter, the DECL we get back will be marked as a
19313 template instantiation, and the appropriate
19314 DECL_TEMPLATE_INFO will be set up. This does not happen for
19315 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
19316 should handle VAR_DECLs as it currently handles
19317 FUNCTION_DECLs. */
19319 {
19322 }
19325 {
19328 }
19330 {
19335 }
19336 }
19338 {
19341 }
19342 else
19345 /* Check for various error cases. Note that if the explicit
19346 instantiation is valid the RESULT will currently be marked as an
19347 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
19348 until we get here. */
19351 {
19352 /* DR 259 [temp.spec].
19354 Both an explicit instantiation and a declaration of an explicit
19355 specialization shall not appear in a program unless the explicit
19356 instantiation follows a declaration of the explicit specialization.
19358 For a given set of template parameters, if an explicit
19359 instantiation of a template appears after a declaration of an
19360 explicit specialization for that template, the explicit
19361 instantiation has no effect. */
19363 }
19365 {
19366 /* [temp.spec]
19368 No program shall explicitly instantiate any template more
19369 than once.
19371 We check DECL_NOT_REALLY_EXTERN so as not to complain when
19372 the first instantiation was `extern' and the second is not,
19373 and EXTERN_P for the opposite case. */
19376 /* If an "extern" explicit instantiation follows an ordinary
19377 explicit instantiation, the template is instantiated. */
19380 }
19382 {
19385 }
19387 {
19390 }
19393 ;
19395 {
19398 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
19401 }
19402 else
19410 }
19412 static void
19414 {
19420 {
19423 }
19424 }
19426 /* Called from do_type_instantiation through binding_table_foreach to
19427 do recursive instantiation for the type bound in ENTRY. */
19428 static void
19430 {
19436 }
19438 /* Called from do_type_instantiation to instantiate a member
19439 (a member function or a static member variable) of an
19440 explicitly instantiated class template. */
19441 static void
19443 {
19448 }
19450 /* Perform an explicit instantiation of template class T. STORAGE, if
19451 non-null, is the RID for extern, inline or static. COMPLAIN is
19452 nonzero if this is called from the parser, zero if called recursively,
19453 since the standard is unclear (as detailed below). */
19455 void
19457 {
19467 {
19468 tree tmpl =
19472 else
19475 }
19480 {
19483 t);
19485 }
19488 {
19490 {
19492 {
19495 "ISO C++ 1998 forbids the use of %<extern%> on "
19497 }
19498 else
19500 "ISO C++ forbids the use of %qE"
19502 }
19510 else
19511 {
19513 storage);
19515 }
19516 }
19519 {
19520 /* DR 259 [temp.spec].
19522 Both an explicit instantiation and a declaration of an explicit
19523 specialization shall not appear in a program unless the explicit
19524 instantiation follows a declaration of the explicit specialization.
19526 For a given set of template parameters, if an explicit
19527 instantiation of a template appears after a declaration of an
19528 explicit specialization for that template, the explicit
19529 instantiation has no effect. */
19531 }
19533 {
19534 /* [temp.spec]
19536 No program shall explicitly instantiate any template more
19537 than once.
19539 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
19540 instantiation was `extern'. If EXTERN_P then the second is.
19541 These cases are OK. */
19548 /* If we've already instantiated the template, just return now. */
19551 }
19559 {
19560 tree tmp;
19562 /* In contrast to implicit instantiation, where only the
19563 declarations, and not the definitions, of members are
19564 instantiated, we have here:
19566 [temp.explicit]
19568 The explicit instantiation of a class template specialization
19569 implies the instantiation of all of its members not
19570 previously explicitly specialized in the translation unit
19571 containing the explicit instantiation.
19573 Of course, we can't instantiate member template classes, since
19574 we don't have any arguments for them. Note that the standard
19575 is unclear on whether the instantiation of the members are
19576 *explicit* instantiations or not. However, the most natural
19577 interpretation is that it should be an explicit instantiation. */
19592 }
19593 }
19595 /* Given a function DECL, which is a specialization of TMPL, modify
19596 DECL to be a re-instantiation of TMPL with the same template
19597 arguments. TMPL should be the template into which tsubst'ing
19598 should occur for DECL, not the most general template.
19600 One reason for doing this is a scenario like this:
19602 template <class T>
19603 void f(const T&, int i);
19605 void g() { f(3, 7); }
19607 template <class T>
19608 void f(const T& t, const int i) { }
19610 Note that when the template is first instantiated, with
19611 instantiate_template, the resulting DECL will have no name for the
19612 first parameter, and the wrong type for the second. So, when we go
19613 to instantiate the DECL, we regenerate it. */
19615 static void
19617 {
19618 /* The arguments used to instantiate DECL, from the most general
19619 template. */
19620 tree args;
19621 tree code_pattern;
19626 /* Make sure that we can see identifiers, and compute access
19627 correctly. */
19631 {
19632 tree decl_parm;
19633 tree pattern_parm;
19634 tree specs;
19648 specs);
19650 /* Merge parameter declarations. */
19653 pattern_parm
19657 {
19658 tree parm_type;
19659 tree attributes;
19664 NULL_TREE);
19670 {
19673 }
19676 }
19677 /* Merge any parameters that match with the function parameter
19678 pack. */
19680 {
19682 tree expanded_types;
19683 /* Expand the TYPE_PACK_EXPANSION that provides the types for
19684 the parameters in this function parameter pack. */
19689 {
19690 tree parm_type;
19691 tree attributes;
19694 /* Rename the parameter to include the index. */
19703 {
19706 }
19708 }
19709 }
19710 /* Merge additional specifiers from the CODE_PATTERN. */
19714 }
19716 {
19724 }
19725 else
19729 }
19731 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
19732 substituted to get DECL. */
19734 tree
19736 {
19739 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
19740 for the instantiation. This is not always the most general
19741 template. Consider, for example:
19743 template <class T>
19744 struct S { template <class U> void f();
19745 template <> void f<int>(); };
19747 and an instantiation of S<double>::f<int>. We want TD to be the
19748 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
19750 more general template. */
19752 /* We must also deal with friend templates. Given:
19754 template <class T> struct S {
19755 template <class U> friend void f() {};
19756 };
19758 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
19759 so far as the language is concerned, but that's still
19760 where we get the pattern for the instantiation from. On
19761 other hand, if the definition comes outside the class, say:
19763 template <class T> struct S {
19764 template <class U> friend void f();
19765 };
19766 template <class U> friend void f() {}
19768 we don't need to look any further. That's what the check for
19769 DECL_INITIAL is for. */
19773 {
19774 /* The present template, TD, should not be a definition. If it
19775 were a definition, we should be using it! Note that we
19776 cannot restructure the loop to just keep going until we find
19777 a template with a definition, since that might go too far if
19778 a specialization was declared, but not defined. */
19780 /* Fetch the more general template. */
19782 }
19785 }
19787 /* Returns true if we need to instantiate this template instance even if we
19788 know we aren't going to emit it.. */
19790 bool
19792 {
19793 /* We always instantiate inline functions so that we can inline them. An
19794 explicit instantiation declaration prohibits implicit instantiation of
19795 non-inline functions. With high levels of optimization, we would
19796 normally inline non-inline functions -- but we're not allowed to do
19797 that for "extern template" functions. Therefore, we check
19798 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
19802 /* And we need to instantiate static data members so that
19803 their initializers are available in integral constant
19804 expressions. */
19807 }
19809 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
19810 instantiate it now, modifying TREE_TYPE (fn). */
19812 void
19814 {
19817 /* Don't instantiate a noexcept-specification from template context. */
19832 {
19836 {
19851 }
19852 else
19856 }
19859 {
19862 else
19864 }
19865 }
19867 /* Produce the definition of D, a _DECL generated from a template. If
19868 DEFER_OK is nonzero, then we don't have to actually do the
19869 instantiation now; we just have to do it sometime. Normally it is
19870 an error if this is an explicit instantiation but D is undefined.
19871 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
19872 explicitly instantiated class template. */
19874 tree
19877 {
19879 tree gen_args;
19880 tree args;
19881 tree td;
19882 tree code_pattern;
19883 tree spec;
19884 tree gen_tmpl;
19891 tree fn_context;
19894 /* This function should only be used to instantiate templates for
19895 functions and static member variables. */
19898 /* Variables are never deferred; if instantiation is required, they
19899 are instantiated right away. That allows for better code in the
19900 case that an expression refers to the value of the variable --
19901 if the variable has a constant value the referring expression can
19902 take advantage of that fact. */
19907 /* Don't instantiate cloned functions. Instead, instantiate the
19908 functions they cloned. */
19916 /* D has already been instantiated or explicitly specialized, so
19917 there's nothing for us to do here.
19919 It might seem reasonable to check whether or not D is an explicit
19920 instantiation, and, if so, stop here. But when an explicit
19921 instantiation is deferred until the end of the compilation,
19922 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
19923 the instantiation. */
19926 /* Check to see whether we know that this template will be
19927 instantiated in some other file, as with "extern template"
19928 extension. */
19931 /* In general, we do not instantiate such templates. */
19939 /* We should already have the extra args. */
19942 /* And what's in the hash table should match D. */
19946 /* This needs to happen before any tsubsting. */
19952 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
19953 for the instantiation. */
19957 /* We should never be trying to instantiate a member of a class
19958 template or partial specialization. */
19963 /* In the case of a friend template whose definition is provided
19964 outside the class, we may have too many arguments. Drop the
19965 ones we don't need. The same is true for specializations. */
19966 args = get_innermost_template_args
19968 else
19972 {
19977 }
19978 else
19979 {
19982 }
19984 /* We may be in the middle of deferred access check. Disable it now. */
19987 /* Unless an explicit instantiation directive has already determined
19988 the linkage of D, remember that a definition is available for
19989 this entity. */
19999 /* If D is a member of an explicitly instantiated class template,
20000 and no definition is available, treat it like an implicit
20001 instantiation. */
20004 {
20005 /* Leave linkage flags alone on instantiations with anonymous
20006 visibility. */
20008 {
20011 }
20013 }
20015 /* Defer all other templates, unless we have been explicitly
20016 forbidden from doing so. */
20018 template. */
20019 ! pattern_defined
20020 /* If it's OK to postpone instantiation, do so. */
20021 || defer_ok
20022 /* If this is a static data member that will be defined
20023 elsewhere, we don't want to instantiate the entire data
20024 member, but we do want to instantiate the initializer so that
20025 we can substitute that elsewhere. */
20027 /* Handle here a deleted function too, avoid generating
20028 its body (c++/61080). */
20030 {
20031 /* The definition of the static data member is now required so
20032 we must substitute the initializer. */
20036 {
20037 tree ns;
20038 tree init;
20047 args,
20050 /* If instantiating the initializer involved instantiating this
20051 again, don't call cp_finish_decl twice. */
20053 {
20054 /* Make sure the initializer is still constant, in case of
20055 circular dependency (template/instantiate6.C). */
20056 const_init
20060 LOOKUP_ONLYCONVERTING);
20061 }
20065 }
20067 /* We restore the source position here because it's used by
20068 add_pending_template. */
20074 /* [temp.explicit]
20076 The definition of a non-exported function template, a
20077 non-exported member function template, or a non-exported
20078 member function or static data member of a class template
20079 shall be present in every translation unit in which it is
20080 explicitly instantiated. */
20084 /* If we're in unevaluated context, we just wanted to get the
20085 constant value; this isn't an odr use, so don't queue
20086 a full instantiation. */
20089 /* ??? Historically, we have instantiated inline functions, even
20090 when marked as "extern template". */
20094 }
20095 /* Tell the repository that D is available in this translation unit
20096 -- and see if it is supposed to be instantiated here. */
20098 {
20099 /* In a PCH file, despite the fact that the repository hasn't
20100 requested instantiation in the PCH it is still possible that
20101 an instantiation will be required in a file that includes the
20102 PCH. */
20105 /* Instantiate inline functions so that the inliner can do its
20106 job, even though we'll not be emitting a copy of this
20107 function. */
20110 }
20116 else
20117 {
20122 }
20124 /* Mark D as instantiated so that recursive calls to
20125 instantiate_decl do not try to instantiate it again. */
20128 /* Regenerate the declaration in case the template has been modified
20129 by a subsequent redeclaration. */
20132 /* We already set the file and line above. Reset them now in case
20133 they changed as a result of calling regenerate_decl_from_template. */
20137 {
20138 tree init;
20141 /* Clear out DECL_RTL; whatever was there before may not be right
20142 since we've reset the type of the declaration. */
20146 /* The initializer is placed in DECL_INITIAL by
20147 regenerate_decl_from_template so we don't need to
20148 push/pop_access_scope again here. Pull it out so that
20149 cp_finish_decl can process it. */
20154 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
20155 initializer. That function will defer actual emission until
20156 we have a chance to determine linkage. */
20159 /* Enter the scope of D so that access-checking works correctly. */
20172 }
20176 {
20178 tree subst_decl;
20179 tree tmpl_parm;
20180 tree spec_parm;
20183 /* Save away the current list, in case we are instantiating one
20184 template from within the body of another. */
20187 /* Set up the list of local specializations. */
20190 /* Set up context. */
20194 else
20197 /* Some typedefs referenced from within the template code need to be
20198 access checked at template instantiation time, i.e now. These
20199 types were added to the template at parsing time. Let's get those
20200 and perform the access checks then. */
20202 gen_args);
20204 /* Create substitution entries for the parameters. */
20209 {
20213 }
20215 {
20217 {
20220 }
20221 else
20222 {
20223 /* Register the (value) argument pack as a specialization of
20224 TMPL_PARM, then move on. */
20227 }
20228 }
20231 /* Substitute into the body of the function. */
20235 else
20236 {
20241 /* Set the current input_location to the end of the function
20242 so that finish_function knows where we are. */
20243 input_location
20246 /* Remember if we saw an infinite loop in the template. */
20247 current_function_infinite_loop
20249 }
20251 /* We don't need the local specializations any more. */
20255 /* Finish the function. */
20259 else
20260 {
20263 }
20267 }
20269 /* We're not deferring instantiation any more. */
20277 out:
20287 }
20289 /* Run through the list of templates that we wish we could
20290 instantiate, and instantiate any we can. RETRIES is the
20291 number of times we retry pending template instantiation. */
20293 void
20295 {
20299 /* Instantiating templates may trigger vtable generation. This in turn
20300 may require further template instantiations. We place a limit here
20301 to avoid infinite loop. */
20303 {
20307 " instantiating %q+D, possibly from virtual table generation"
20311 /* Pretend that we defined it. */
20314 }
20316 do
20317 {
20322 {
20327 {
20328 tree fn;
20331 {
20335 fn;
20343 }
20346 }
20347 else
20348 {
20351 {
20352 instantiation
20358 }
20362 }
20365 /* If INSTANTIATION has been instantiated, then we don't
20366 need to consider it again in the future. */
20368 else
20369 {
20372 }
20375 }
20377 }
20381 }
20383 /* Substitute ARGVEC into T, which is a list of initializers for
20384 either base class or a non-static data member. The TREE_PURPOSEs
20385 are DECLs, and the TREE_VALUEs are the initializer values. Used by
20386 instantiate_decl. */
20388 static tree
20390 {
20394 {
20395 tree decl;
20396 tree init;
20402 {
20403 tree expr;
20404 tree arg;
20406 /* Expand the base class expansion type into separate base
20407 classes. */
20409 tf_warning_or_error,
20410 NULL_TREE);
20414 /* We'll be building separate TREE_LISTs of arguments for
20415 each base. */
20421 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
20422 expand each argument in the TREE_VALUE of t. */
20429 /* VOID_TYPE_NODE is used to indicate
20430 value-initialization. */
20431 {
20434 }
20435 else
20436 {
20437 /* Substitute parameter packs into each argument in the
20438 TREE_LIST. */
20441 {
20442 tree expanded_exprs;
20444 /* Expand the argument. */
20446 expanded_exprs
20448 tf_warning_or_error,
20449 NULL_TREE);
20453 /* Prepend each of the expanded expressions to the
20454 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
20456 {
20461 }
20462 }
20465 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
20466 since we built them backwards. */
20468 {
20471 }
20472 }
20473 }
20476 {
20478 {
20482 }
20483 else
20484 {
20485 tree tmp;
20500 /* If we had an initializer but it instantiated to nothing,
20501 value-initialize the object. This will only occur when
20502 the initializer was a pack expansion where the parameter
20503 packs used in that expansion were of length zero. */
20506 }
20509 {
20513 }
20514 }
20515 }
20517 }
20519 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
20521 static void
20523 {
20528 else
20530 }
20532 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
20533 is the instantiation (which should have been created with
20534 start_enum) and ARGS are the template arguments to use. */
20536 static void
20538 {
20539 tree e;
20545 {
20546 tree value;
20547 tree decl;
20550 /* Note that in a template enum, the TREE_VALUE is the
20551 CONST_DECL, not the corresponding INTEGER_CST. */
20556 /* Give this enumeration constant the correct access. */
20559 /* Actually build the enumerator itself. */
20560 build_enumerator
20562 }
20572 }
20574 /* DECL is a FUNCTION_DECL that is a template specialization. Return
20575 its type -- but without substituting the innermost set of template
20576 arguments. So, innermost set of template parameters will appear in
20577 the type. */
20579 tree
20581 {
20582 tree fn_type;
20583 tree tmpl;
20584 tree targs;
20585 tree tparms;
20593 /* There should be as many levels of arguments as there are levels
20594 of parameters. */
20600 /* No substitution is necessary. */
20601 ;
20602 else
20603 {
20605 tree partial_args;
20607 /* Replace the innermost level of the TARGS with NULL_TREEs to
20608 let tsubst know not to substitute for those parameters. */
20617 /* Make sure that we can see identifiers, and compute access
20618 correctly. */
20622 /* Now, do the (partial) substitution to figure out the
20623 appropriate function type. */
20627 /* Substitute into the template parameters to obtain the real
20628 innermost set of parameters. This step is important if the
20629 innermost set of template parameters contains value
20630 parameters whose types depend on outer template parameters. */
20635 }
20638 }
20640 /* Return truthvalue if we're processing a template different from
20641 the last one involved in diagnostics. */
20642 bool
20644 {
20646 }
20648 /* Remember current template involved in diagnostics. */
20649 void
20651 {
20653 }
20657 {
20659 }
20661 /* [temp.param] Check that template non-type parm TYPE is of an allowable
20662 type. Return zero for ok, nonzero for disallowed. Issue error and
20663 warning messages under control of COMPLAIN. */
20665 static int
20667 {
20684 {
20687 else
20689 type);
20690 }
20692 }
20694 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
20695 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
20697 static bool
20699 {
20700 tree scope;
20702 /* [temp.dep.type]
20704 A type is dependent if it is:
20706 -- a template parameter. Template template parameters are types
20707 for us (since TYPE_P holds true for them) so we handle
20708 them here. */
20712 /* -- a qualified-id with a nested-name-specifier which contains a
20713 class-name that names a dependent type or whose unqualified-id
20714 names a dependent type. */
20717 /* -- a cv-qualified type where the cv-unqualified type is
20718 dependent. */
20720 /* -- a compound type constructed from any dependent type. */
20730 {
20731 tree arg_type;
20736 arg_type;
20741 }
20742 /* -- an array type constructed from any dependent type or whose
20743 size is specified by a constant expression that is
20744 value-dependent.
20746 We checked for type- and value-dependence of the bounds in
20747 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
20749 {
20754 }
20756 /* -- a template-id in which either the template name is a template
20757 parameter ... */
20760 /* ... or any of the template arguments is a dependent type or
20761 an expression that is type-dependent or value-dependent. */
20763 && (any_dependent_template_arguments_p
20767 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
20768 dependent; if the argument of the `typeof' expression is not
20769 type-dependent, then it should already been have resolved. */
20775 /* A template argument pack is dependent if any of its packed
20776 arguments are. */
20778 {
20784 }
20786 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
20787 be template parameters. */
20791 /* The standard does not specifically mention types that are local
20792 to template functions or local classes, but they should be
20793 considered dependent too. For example:
20795 template <int I> void f() {
20796 enum E { a = I };
20797 S<sizeof (E)> s;
20798 }
20800 The size of `E' cannot be known until the value of `I' has been
20801 determined. Therefore, `E' must be considered dependent. */
20805 /* Don't use type_dependent_expression_p here, as it can lead
20806 to infinite recursion trying to determine whether a lambda
20807 nested in a lambda is dependent (c++/47687). */
20811 && (any_dependent_template_arguments_p
20815 /* Other types are non-dependent. */
20817 }
20819 /* Returns TRUE if TYPE is dependent, in the sense of
20820 [temp.dep.type]. Note that a NULL type is considered dependent. */
20822 bool
20824 {
20825 /* If there are no template parameters in scope, then there can't be
20826 any dependent types. */
20828 {
20829 /* If we are not processing a template, then nobody should be
20830 providing us with a dependent type. */
20834 }
20836 /* If the type is NULL, we have not computed a type for the entity
20837 in question; in that case, the type is dependent. */
20841 /* Erroneous types can be considered non-dependent. */
20845 /* If we have not already computed the appropriate value for TYPE,
20846 do so now. */
20848 {
20851 }
20854 }
20856 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
20857 lookup. In other words, a dependent type that is not the current
20858 instantiation. */
20860 bool
20862 {
20865 }
20867 /* T is a SCOPE_REF; return whether we need to consider it
20868 instantiation-dependent so that we can check access at instantiation
20869 time even though we know which member it resolves to. */
20871 static bool
20873 {
20879 else
20881 }
20883 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
20884 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
20885 expression. */
20887 /* Note that this predicate is not appropriate for general expressions;
20888 only constant expressions (that satisfy potential_constant_expression)
20889 can be tested for value dependence. */
20891 bool
20893 {
20897 /* A name declared with a dependent type. */
20902 {
20904 /* A name that has not been looked up -- must be dependent. */
20908 /* A non-type template parm. */
20912 /* A non-type template parm. */
20918 /* A constant with literal type and is initialized
20919 with an expression that is value-dependent.
20921 Note that a non-dependent parenthesized initializer will have
20922 already been replaced with its constant value, so if we see
20923 a TREE_LIST it must be dependent. */
20936 /* These expressions are value-dependent if the type to which
20937 the cast occurs is dependent or the expression being casted
20938 is value-dependent. */
20939 {
20945 /* A functional cast has a list of operands. */
20948 {
20949 /* If there are no operands, it must be an expression such
20950 as "int()". This should not happen for aggregate types
20951 because it would form non-constant expressions. */
20956 }
20962 }
20967 /* FALLTHRU */
20970 /* A `sizeof' expression is value-dependent if the operand is
20971 type-dependent or is a pack expansion. */
20980 /* An 'encode' expression is value-dependent if the operand is
20981 type-dependent. */
20990 /* All instantiation-dependent expressions should also be considered
20991 value-dependent. */
20999 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
21000 is value-dependent. */
21001 {
21010 }
21013 {
21017 }
21028 {
21032 }
21035 {
21042 {
21044 /* In a call to a constexpr member function, look through the
21045 implicit ADDR_EXPR on the object argument so that it doesn't
21046 cause the call to be considered value-dependent. We also
21047 look through it in potential_constant_expression. */
21054 }
21056 }
21059 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
21060 type-dependent. */
21064 {
21066 tree val;
21073 }
21076 /* Treat a GNU statement expression as dependent to avoid crashing
21077 under fold_non_dependent_expr; it can't be constant. */
21081 /* A constant expression is value-dependent if any subexpression is
21082 value-dependent. */
21084 {
21091 {
21095 {
21098 /* In some cases, some of the operands may be missing.l
21099 (For example, in the case of PREDECREMENT_EXPR, the
21100 amount to increment by may be missing.) That doesn't
21101 make the expression dependent. */
21104 }
21105 }
21109 }
21111 }
21113 /* The expression is not value-dependent. */
21115 }
21117 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
21118 [temp.dep.expr]. Note that an expression with no type is
21119 considered dependent. Other parts of the compiler arrange for an
21120 expression with type-dependent subexpressions to have no type, so
21121 this function doesn't have to be fully recursive. */
21123 bool
21125 {
21132 /* An unresolved name is always dependent. */
21136 /* Some expression forms are never type-dependent. */
21149 /* The types of these expressions depends only on the type to which
21150 the cast occurs. */
21159 /* The types of these expressions depends only on the type created
21160 by the expression. */
21163 {
21164 /* For NEW_EXPR tree nodes created inside a template, either
21165 the object type itself or a TREE_LIST may appear as the
21166 operand 1. */
21169 /* This is an array type. We need to check array dimensions
21170 as well. */
21172 || value_dependent_expression_p
21174 else
21176 }
21179 {
21183 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
21184 contains an identifier associated by name lookup with one or more
21185 declarations declared with a dependent type, or...a
21186 nested-name-specifier or qualified-id that names a member of an
21187 unknown specialization. */
21190 }
21195 && (any_dependent_template_arguments_p
21207 {
21208 tree elt;
21212 {
21215 }
21217 }
21219 /* A static data member of the current instantiation with incomplete
21220 array type is type-dependent, as the definition and specializations
21221 can have different bounds. */
21228 /* An array of unknown bound depending on a variadic parameter, eg:
21230 template<typename... Args>
21231 void foo (Args... args)
21232 {
21233 int arr[] = { args... };
21234 }
21236 template<int... vals>
21237 void bar ()
21238 {
21239 int arr[] = { vals... };
21240 }
21242 If the array has no length and has an initializer, it must be that
21243 we couldn't determine its length in cp_complete_array_type because
21244 it is dependent. */
21252 {
21257 {
21263 }
21264 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
21268 /* Always dependent, on the number of arguments if nothing else. */
21273 {
21278 }
21281 {
21286 }
21291 {
21295 }
21297 }
21302 }
21304 /* walk_tree callback function for instantiation_dependent_expression_p,
21305 below. Returns non-zero if a dependent subexpression is found. */
21307 static tree
21310 {
21312 {
21313 /* We don't have to worry about decltype currently because decltype
21314 of an instantiation-dependent expr is a dependent type. This
21315 might change depending on the resolution of DR 1172. */
21318 }
21321 {
21322 /* Don't treat an argument list as dependent just because it has no
21323 TREE_TYPE. */
21330 /* A constant with a dependent initializer is dependent. */
21338 /* Handle expressions with type operands. */
21343 {
21348 {
21351 else
21352 {
21355 }
21356 }
21358 }
21370 /* In a template, finish_class_member_access_expr creates a
21371 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
21372 type-dependent, so that we can check access control at
21373 instantiation time (PR 42277). See also Core issue 1273. */
21380 else
21383 /* Treat statement-expressions as dependent. */
21389 }
21393 else
21395 }
21397 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
21398 sense defined by the ABI:
21400 "An expression is instantiation-dependent if it is type-dependent
21401 or value-dependent, or it has a subexpression that is type-dependent
21402 or value-dependent." */
21404 bool
21406 {
21407 tree result;
21418 }
21420 /* Like type_dependent_expression_p, but it also works while not processing
21421 a template definition, i.e. during substitution or mangling. */
21423 bool
21425 {
21431 }
21433 /* Returns TRUE if ARGS contains a type-dependent expression. */
21435 bool
21437 {
21439 tree arg;
21442 {
21445 }
21447 }
21449 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
21450 expressions) contains any type-dependent expressions. */
21452 bool
21454 {
21460 }
21462 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
21463 expressions) contains any value-dependent expressions. */
21465 bool
21467 {
21473 }
21475 /* Returns TRUE if the ARG (a template argument) is dependent. */
21477 bool
21479 {
21483 /* Assume a template argument that was wrongly written by the user
21484 is dependent. This is consistent with what
21485 any_dependent_template_arguments_p [that calls this function]
21486 does. */
21497 {
21501 {
21504 }
21507 }
21510 else
21513 }
21515 /* Returns true if ARGS (a collection of template arguments) contains
21516 any types that require structural equality testing. */
21518 bool
21520 {
21530 {
21533 {
21539 {
21540 /* Look inside the argument pack. */
21543 }
21546 {
21559 }
21560 }
21561 }
21564 }
21566 /* Returns true if ARGS (a collection of template arguments) contains
21567 any dependent arguments. */
21569 bool
21571 {
21581 {
21586 }
21589 }
21591 /* Returns TRUE if the template TMPL is dependent. */
21593 bool
21595 {
21597 {
21599 {
21603 }
21605 }
21607 /* Template template parameters are dependent. */
21611 /* So are names that have not been looked up. */
21614 /* So are member templates of dependent classes. */
21618 }
21620 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
21622 bool
21624 {
21627 }
21629 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
21630 is dependent. */
21632 bool
21634 {
21641 {
21662 {
21666 }
21670 {
21674 {
21679 }
21680 }
21681 }
21684 }
21686 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
21687 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
21688 no such TYPE can be found. Note that this function peers inside
21689 uninstantiated templates and therefore should be used only in
21690 extremely limited situations. ONLY_CURRENT_P restricts this
21691 peering to the currently open classes hierarchy (which is required
21692 when comparing types). */
21694 tree
21696 {
21697 tree scope;
21698 tree name;
21699 tree decl;
21701 tree pushed_scope;
21702 tree result;
21707 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
21708 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
21709 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
21710 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
21711 identifier of the TYPENAME_TYPE anymore.
21712 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
21713 TYPENAME_TYPE instead, we avoid messing up with a possible
21714 typedef variant case. */
21717 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
21718 it first before we can figure out what NAME refers to. */
21720 {
21722 /* Given a class template A with a dependent base with nested type C,
21723 typedef typename A::C::C C will land us here, as trying to resolve
21724 the initial A::C leads to the local C typedef, which leads back to
21725 A::C::C. So we break the recursion now. */
21727 else
21729 }
21730 /* If we don't know what SCOPE refers to, then we cannot resolve the
21731 TYPENAME_TYPE. */
21734 /* If the SCOPE is a template type parameter, we have no way of
21735 resolving the name. */
21738 /* If the SCOPE is not the current instantiation, there's no reason
21739 to look inside it. */
21742 /* If this is a typedef, we don't want to look inside (c++/11987). */
21745 /* If SCOPE isn't the template itself, it will not have a valid
21746 TYPE_FIELDS list. */
21748 /* scope is either the template itself or a compatible instantiation
21749 like X<T>, so look up the name in the original template. */
21751 else
21752 /* scope is a partial instantiation, so we can't do the lookup or we
21753 will lose the template arguments. */
21755 /* Enter the SCOPE so that name lookup will be resolved as if we
21756 were in the class definition. In particular, SCOPE will no
21757 longer be considered a dependent type. */
21759 /* Look up the declaration. */
21761 tf_warning_or_error);
21765 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
21766 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
21771 {
21775 }
21778 {
21779 tree tmpl;
21780 tree args;
21781 /* Obtain the template and the arguments. */
21784 /* Instantiate the template. */
21790 }
21792 /* Leave the SCOPE. */
21796 /* If we failed to resolve it, return the original typename. */
21800 /* If lookup found a typename type, resolve that too. */
21802 {
21803 /* Ill-formed programs can cause infinite recursion here, so we
21804 must catch that. */
21808 }
21810 /* Qualify the resulting type. */
21816 }
21818 /* EXPR is an expression which is not type-dependent. Return a proxy
21819 for EXPR that can be used to compute the types of larger
21820 expressions containing EXPR. */
21822 tree
21824 {
21825 tree inner_expr;
21827 #ifdef ENABLE_CHECKING
21828 /* Try to get a constant value for all non-dependent expressions in
21829 order to expose bugs in *_dependent_expression_p and constexpr. */
21832 #endif
21834 /* Preserve OVERLOADs; the functions must be available to resolve
21835 types. */
21846 /* There is no need to return a proxy for a variable. */
21849 /* Preserve string constants; conversions from string constants to
21850 "char *" are allowed, even though normally a "const char *"
21851 cannot be used to initialize a "char *". */
21854 /* Preserve void and arithmetic constants, as an optimization -- there is no
21855 reason to create a new node. */
21860 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
21861 There is at least one place where we want to know that a
21862 particular expression is a throw-expression: when checking a ?:
21863 expression, there are special rules if the second or third
21864 argument is a throw-expression. */
21868 /* Don't wrap an initializer list, we need to be able to look inside. */
21872 /* Don't wrap a dummy object, we need to be able to test for it. */
21891 /* If the type is unknown, it can't really be non-dependent */
21894 /* Otherwise, build a NON_DEPENDENT_EXPR. */
21896 }
21898 /* ARGS is a vector of expressions as arguments to a function call.
21899 Replace the arguments with equivalent non-dependent expressions.
21900 This modifies ARGS in place. */
21902 void
21904 {
21906 tree arg;
21909 {
21913 }
21914 }
21916 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
21917 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
21918 parms. */
21920 static tree
21922 {
21935 }
21937 tree
21939 {
21941 }
21943 tree
21945 {
21947 }
21949 /* Given type ARG, return std::initializer_list<ARG>. */
21951 static tree
21953 {
21954 tree std_init_list = namespace_binding
21956 tree argvec;
21958 {
21962 }
21967 }
21969 /* Replace auto in TYPE with std::initializer_list<auto>. */
21971 static tree
21973 {
21980 }
21982 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
21983 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
21985 tree
21987 {
21988 tree targs;
21994 /* Defining a subset of type-dependent expressions that we can deduce
21995 from ahead of time isn't worth the trouble. */
21998 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
21999 with either a new invented type template parameter U or, if the
22000 initializer is a braced-init-list (8.5.4), with
22001 std::initializer_list<U>. */
22009 {
22015 {
22018 }
22019 }
22020 else
22021 {
22032 {
22034 /* Try again at instantiation time. */
22037 /* If type is error_mark_node a diagnostic must have been
22038 emitted by now. Also, having a mention to '<type error>'
22039 in the diagnostic is not really useful to the user. */
22040 {
22044 else
22046 }
22048 }
22049 }
22051 /* If the list of declarators contains more than one declarator, the type
22052 of each declared variable is determined as described above. If the
22053 type deduced for the template parameter U is not the same in each
22054 deduction, the program is ill-formed. */
22057 {
22063 else
22067 }
22073 }
22075 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
22076 result. */
22078 tree
22080 {
22081 tree argvec;
22088 /* For a late-specified return type in a template type-parameter, we
22089 need to add a dummy argument level for its parmlist. */
22090 argvec = add_to_template_args
22095 }
22097 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
22098 'decltype(auto)'. */
22100 bool
22102 {
22107 else
22109 }
22111 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
22112 a use of `auto'. Returns NULL_TREE otherwise. */
22114 tree
22116 {
22118 }
22120 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
22121 'decltype(auto)' or a concept. */
22123 bool
22125 {
22127 }
22129 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
22130 a concept identifier) iff TYPE contains a use of a generic type. Returns
22131 NULL_TREE otherwise. */
22133 tree
22135 {
22137 }
22140 /* For a given template T, return the vector of typedefs referenced
22141 in T for which access check is needed at T instantiation time.
22142 T is either a FUNCTION_DECL or a RECORD_TYPE.
22143 Those typedefs were added to T by the function
22144 append_type_to_template_for_access_check. */
22148 {
22149 tree ti;
22160 {
22165 }
22168 }
22170 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
22171 tied to T. That list of typedefs will be access checked at
22172 T instantiation time.
22173 T is either a FUNCTION_DECL or a RECORD_TYPE.
22174 TYPE_DECL is a TYPE_DECL node representing a typedef.
22175 SCOPE is the scope through which TYPE_DECL is accessed.
22176 LOCATION is the location of the usage point of TYPE_DECL.
22178 This function is a subroutine of
22179 append_type_to_template_for_access_check. */
22181 static void
22183 tree type_decl,
22184 tree scope,
22185 location_t location)
22186 {
22187 qualified_typedef_usage_t typedef_usage;
22188 tree ti;
22195 && type_decl
22209 }
22211 /* Append TYPE_DECL to the template TEMPL.
22212 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
22213 At TEMPL instanciation time, TYPE_DECL will be checked to see
22214 if it can be accessed through SCOPE.
22215 LOCATION is the location of the usage point of TYPE_DECL.
22217 e.g. consider the following code snippet:
22219 class C
22220 {
22221 typedef int myint;
22222 };
22224 template<class U> struct S
22225 {
22226 C::myint mi; // <-- usage point of the typedef C::myint
22227 };
22229 S<char> s;
22231 At S<char> instantiation time, we need to check the access of C::myint
22232 In other words, we need to check the access of the myint typedef through
22233 the C scope. For that purpose, this function will add the myint typedef
22234 and the scope C through which its being accessed to a list of typedefs
22235 tied to the template S. That list will be walked at template instantiation
22236 time and access check performed on each typedefs it contains.
22237 Note that this particular code snippet should yield an error because
22238 myint is private to C. */
22240 void
22242 tree type_decl,
22243 tree scope,
22244 location_t location)
22245 {
22251 /* Make sure we don't append the type to the template twice. */
22258 }
22260 /* Convert the generic type parameters in PARM that match the types given in the
22261 range [START_IDX, END_IDX) from the current_template_parms into generic type
22262 packs. */
22264 tree
22266 {
22277 {
22278 /* Create a distinct parameter pack type from the current parm and add it
22279 to the replacement args to tsubst below into the generic function
22280 parameter. */
22295 }
22301 /* If there are more levels then build up the replacement with the outer
22302 template parms. */
22306 replacement);
22309 }
22312 /* Set up the hash tables for template instantiations. */
22314 void
22316 {
22319 }
22321 /* Print stats about the template hash tables for -fstats. */
22323 void
22325 {
22334 }