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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 T is a specialization of an alias template. */
5273 bool
5275 {
5283 }
5285 /* Return TRUE iff T is a specialization of an alias template with
5286 dependent template-arguments. */
5288 bool
5290 {
5293 }
5295 /* Return the number of innermost template parameters in TMPL. */
5297 static int
5299 {
5302 }
5304 /* Return either TMPL or another template that it is equivalent to under DR
5305 1286: An alias that just changes the name of a template is equivalent to
5306 the other template. */
5308 static tree
5310 {
5313 {
5316 {
5321 {
5322 tree alias_args = INNERMOST_TEMPLATE_ARGS
5326 /* The alias type is equivalent to the pattern of the
5327 underlying template, so strip the alias. */
5330 }
5331 }
5333 }
5335 }
5337 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5338 must be a function or a pointer-to-function type, as specified
5339 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5340 and check that the resulting function has external linkage. */
5342 static tree
5344 tsubst_flags_t complain)
5345 {
5348 linkage_kind linkage;
5360 /* [temp.arg.nontype]/1
5362 A template-argument for a non-type, non-template template-parameter
5363 shall be one of:
5364 [...]
5365 -- the address of an object or function with external [C++11: or
5366 internal] linkage. */
5369 {
5371 {
5377 else
5380 }
5382 }
5386 {
5388 {
5393 else
5397 }
5399 }
5402 }
5404 /* Subroutine of convert_nontype_argument.
5405 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5406 Emit an error otherwise. */
5408 static bool
5410 tsubst_flags_t complain)
5411 {
5422 {
5426 }
5428 }
5430 /* Returns TRUE iff the address of OP is value-dependent.
5432 14.6.2.4 [temp.dep.temp]:
5433 A non-integral non-type template-argument is dependent if its type is
5434 dependent or it has either of the following forms
5435 qualified-id
5436 & qualified-id
5437 and contains a nested-name-specifier which specifies a class-name that
5438 names a dependent type.
5440 We generalize this to just say that the address of a member of a
5441 dependent class is value-dependent; the above doesn't cover the
5442 address of a static data member named with an unqualified-id. */
5444 static bool
5446 {
5447 /* We could use get_inner_reference here, but there's no need;
5448 this is only relevant for template non-type arguments, which
5449 can only be expressed as &id-expression. */
5451 {
5455 }
5458 }
5460 /* The next set of functions are used for providing helpful explanatory
5461 diagnostics for failed overload resolution. Their messages should be
5462 indented by two spaces for consistency with the messages in
5463 call.c */
5465 static int
5467 {
5469 }
5471 static int
5473 {
5478 }
5480 static int
5482 {
5484 }
5486 static int
5488 {
5494 }
5496 static int
5498 {
5502 }
5504 static int
5506 {
5509 " template parameter %qD is not a parameter pack, but "
5513 }
5515 static int
5517 {
5520 " template argument %qE does not match "
5524 }
5526 static int
5528 {
5532 }
5534 static int
5536 {
5542 }
5544 static int
5546 {
5548 {
5553 else
5555 " deduced conflicting values for non-type parameter "
5557 }
5559 }
5561 static int
5563 {
5566 " variable-sized array type %qT is not "
5568 arg);
5570 }
5572 static int
5574 {
5578 arg);
5580 }
5582 static int
5584 {
5586 {
5592 else
5597 }
5599 }
5601 static int
5603 {
5605 }
5607 static int
5610 {
5612 }
5614 static int
5617 {
5623 }
5625 static int
5628 {
5631 {
5639 }
5641 }
5643 static int
5645 {
5648 " template parameters of a template template argument are "
5651 }
5653 static int
5655 {
5661 }
5663 static int
5665 {
5670 }
5672 static int
5674 {
5678 arg);
5680 }
5682 /* Attempt to convert the non-type template parameter EXPR to the
5683 indicated TYPE. If the conversion is successful, return the
5684 converted value. If the conversion is unsuccessful, return
5685 NULL_TREE if we issued an error message, or error_mark_node if we
5686 did not. We issue error messages for out-and-out bad template
5687 parameters, but not simply because the conversion failed, since we
5688 might be just trying to do argument deduction. Both TYPE and EXPR
5689 must be non-dependent.
5691 The conversion follows the special rules described in
5692 [temp.arg.nontype], and it is much more strict than an implicit
5693 conversion.
5695 This function is called twice for each template argument (see
5696 lookup_template_class for a more accurate description of this
5697 problem). This means that we need to handle expressions which
5698 are not valid in a C++ source, but can be created from the
5699 first call (for instance, casts to perform conversions). These
5700 hacks can go away after we fix the double coercion problem. */
5702 static tree
5704 {
5705 tree expr_type;
5707 /* Detect immediately string literals as invalid non-type argument.
5708 This special-case is not needed for correctness (we would easily
5709 catch this later), but only to provide better diagnostic for this
5710 common user mistake. As suggested by DR 100, we do not mention
5711 linkage issues in the diagnostic as this is not the point. */
5712 /* FIXME we're making this OK. */
5714 {
5720 }
5722 /* Add the ADDR_EXPR now for the benefit of
5723 value_dependent_expression_p. */
5726 {
5730 }
5732 /* If we are in a template, EXPR may be non-dependent, but still
5733 have a syntactic, rather than semantic, form. For example, EXPR
5734 might be a SCOPE_REF, rather than the VAR_DECL to which the
5735 SCOPE_REF refers. Preserving the qualifying scope is necessary
5736 so that access checking can be performed when the template is
5737 instantiated -- but here we need the resolved form so that we can
5738 convert the argument. */
5749 else
5752 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
5753 to a non-type argument of "nullptr". */
5757 /* In C++11, integral or enumeration non-type template arguments can be
5758 arbitrary constant expressions. Pointer and pointer to
5759 member arguments can be general constant expressions that evaluate
5760 to a null value, but otherwise still need to be of a specific form. */
5762 {
5764 /* A PTRMEM_CST is already constant, and a valid template
5765 argument for a parameter of pointer to member type, we just want
5766 to leave it in that form rather than lower it to a
5771 {
5776 }
5777 }
5779 /* HACK: Due to double coercion, we can get a
5780 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5781 which is the tree that we built on the first call (see
5782 below when coercing to reference to object or to reference to
5783 function). We just strip everything and get to the arg.
5784 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5785 for examples. */
5787 {
5793 {
5794 /* ??? Maybe we could use convert_from_reference here, but we
5795 would need to relax its constraints because the NOP_EXPR
5796 could actually change the type to something more cv-qualified,
5797 and this is not folded by convert_from_reference. */
5802 && (same_type_ignoring_top_level_qualifiers_p
5805 {
5808 }
5809 }
5810 }
5812 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5813 parameter is a pointer to object, through decay and
5814 qualification conversion. Let's strip everything. */
5816 {
5821 {
5822 /* Skip the ADDR_EXPR only if it is part of the decay for
5823 an array. Otherwise, it is part of the original argument
5824 in the source code. */
5829 }
5830 }
5832 /* [temp.arg.nontype]/5, bullet 1
5834 For a non-type template-parameter of integral or enumeration type,
5835 integral promotions (_conv.prom_) and integral conversions
5836 (_conv.integral_) are applied. */
5838 {
5847 /* Notice that there are constant expressions like '4 % 0' which
5848 do not fold into integer constants. */
5850 {
5852 {
5863 /* else cxx_constant_value complained but gave us
5864 a real constant, so go ahead. */
5866 }
5867 else
5869 }
5871 /* Avoid typedef problems. */
5874 }
5875 /* [temp.arg.nontype]/5, bullet 2
5877 For a non-type template-parameter of type pointer to object,
5878 qualification conversions (_conv.qual_) and the array-to-pointer
5879 conversion (_conv.array_) are applied. */
5881 {
5882 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
5884 A template-argument for a non-type, non-template template-parameter
5885 shall be one of: [...]
5887 -- the name of a non-type template-parameter;
5888 -- the address of an object or function with external linkage, [...]
5889 expressed as "& id-expression" where the & is optional if the name
5890 refers to a function or array, or if the corresponding
5891 template-parameter is a reference.
5893 Here, we do not care about functions, as they are invalid anyway
5894 for a parameter of type pointer-to-object. */
5897 /* Non-type template parameters are OK. */
5898 ;
5903 {
5905 {
5908 "because %qD is a variable, not the address of "
5911 }
5913 {
5919 }
5920 /* Other values, like integer constants, might be valid
5921 non-type arguments of some other type. */
5923 }
5924 else
5925 {
5926 tree decl;
5931 {
5936 }
5938 {
5944 }
5946 {
5951 }
5952 }
5961 }
5962 /* [temp.arg.nontype]/5, bullet 3
5964 For a non-type template-parameter of type reference to object, no
5965 conversions apply. The type referred to by the reference may be more
5966 cv-qualified than the (otherwise identical) type of the
5967 template-argument. The template-parameter is bound directly to the
5968 template-argument, which must be an lvalue. */
5970 {
5972 expr_type))
5976 {
5981 }
5984 {
5989 }
5991 /* [temp.arg.nontype]/1
5993 A template-argument for a non-type, non-template template-parameter
5994 shall be one of: [...]
5996 -- the address of an object or function with external linkage. */
5999 {
6002 {
6005 "because a reference variable does not have a constant "
6008 }
6009 }
6012 {
6018 }
6021 {
6027 }
6030 }
6031 /* [temp.arg.nontype]/5, bullet 4
6033 For a non-type template-parameter of type pointer to function, only
6034 the function-to-pointer conversion (_conv.func_) is applied. If the
6035 template-argument represents a set of overloaded functions (or a
6036 pointer to such), the matching function is selected from the set
6037 (_over.over_). */
6039 {
6040 /* If the argument is a template-id, we might not have enough
6041 context information to decay the pointer. */
6043 {
6047 }
6050 /* Null pointer values are OK in C++11. */
6056 }
6057 /* [temp.arg.nontype]/5, bullet 5
6059 For a non-type template-parameter of type reference to function, no
6060 conversions apply. If the template-argument represents a set of
6061 overloaded functions, the matching function is selected from the set
6062 (_over.over_). */
6064 {
6066 {
6068 {
6073 }
6075 }
6082 }
6083 /* [temp.arg.nontype]/5, bullet 6
6085 For a non-type template-parameter of type pointer to member function,
6086 no conversions apply. If the template-argument represents a set of
6087 overloaded member functions, the matching member function is selected
6088 from the set (_over.over_). */
6090 {
6095 /* [temp.arg.nontype] bullet 1 says the pointer to member
6096 expression must be a pointer-to-member constant. */
6100 /* There is no way to disable standard conversions in
6101 resolve_address_of_overloaded_function (called by
6102 instantiate_type). It is possible that the call succeeded by
6103 converting &B::I to &D::I (where B is a base of D), so we need
6104 to reject this conversion here.
6106 Actually, even if there was a way to disable standard conversions,
6107 it would still be better to reject them here so that we can
6108 provide a superior diagnostic. */
6110 {
6112 {
6116 /* If we are just one standard conversion off, explain. */
6120 }
6122 }
6123 }
6124 /* [temp.arg.nontype]/5, bullet 7
6126 For a non-type template-parameter of type pointer to data member,
6127 qualification conversions (_conv.qual_) are applied. */
6129 {
6130 /* [temp.arg.nontype] bullet 1 says the pointer to member
6131 expression must be a pointer-to-member constant. */
6138 }
6140 {
6142 {
6147 }
6149 }
6150 /* A template non-type parameter must be one of the above. */
6151 else
6154 /* Sanity check: did we actually convert the argument to the
6155 right type? */
6159 }
6161 /* Subroutine of coerce_template_template_parms, which returns 1 if
6162 PARM_PARM and ARG_PARM match using the rule for the template
6163 parameters of template template parameters. Both PARM and ARG are
6164 template parameters; the rest of the arguments are the same as for
6165 coerce_template_template_parms.
6166 */
6167 static int
6169 tree arg,
6170 tsubst_flags_t complain,
6171 tree in_decl,
6172 tree outer_args)
6173 {
6182 {
6184 /* We encounter instantiations of templates like
6185 template <template <template <class> class> class TT>
6186 class C; */
6187 {
6194 }
6195 /* Fall through. */
6200 /* Argument is a parameter pack but parameter is not. */
6205 /* The tsubst call is used to handle cases such as
6207 template <int> class C {};
6208 template <class T, template <T> class TT> class D {};
6209 D<int, C> d;
6211 i.e. the parameter list of TT depends on earlier parameters. */
6213 && !same_type_p
6220 /* Argument is a parameter pack but parameter is not. */
6227 }
6230 }
6233 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
6234 template template parameters. Both PARM_PARMS and ARG_PARMS are
6235 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
6236 or PARM_DECL.
6238 Consider the example:
6239 template <class T> class A;
6240 template<template <class U> class TT> class B;
6242 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
6243 the parameters to A, and OUTER_ARGS contains A. */
6245 static int
6247 tree arg_parms,
6248 tsubst_flags_t complain,
6249 tree in_decl,
6250 tree outer_args)
6251 {
6262 /* Determine whether we have a parameter pack at the end of the
6263 template template parameter's template parameter list. */
6265 {
6272 {
6286 }
6287 }
6293 /* Check all of the template parameters except the parameter pack at
6294 the end (if any). */
6296 {
6305 outer_args))
6308 }
6311 {
6312 /* Check each of the template parameters in the template
6313 argument against the template parameter pack at the end of
6314 the template template parameter. */
6321 {
6328 outer_args))
6330 }
6331 }
6334 }
6336 /* Verifies that the deduced template arguments (in TARGS) for the
6337 template template parameters (in TPARMS) represent valid bindings,
6338 by comparing the template parameter list of each template argument
6339 to the template parameter list of its corresponding template
6340 template parameter, in accordance with DR150. This
6341 routine can only be called after all template arguments have been
6342 deduced. It will return TRUE if all of the template template
6343 parameter bindings are okay, FALSE otherwise. */
6344 bool
6346 {
6350 /* We're dealing with template parms in this process. */
6356 {
6361 {
6366 {
6367 /* Look inside the argument pack. */
6370 }
6373 {
6377 /* Extract the next argument from the argument
6378 pack. */
6382 /* Look at the pattern of the pack expansion. */
6385 /* Extract the template parameters from the template
6386 argument. */
6392 /* Verify that we can coerce the template template
6393 parameters from the template argument to the template
6394 parameter. This requires an exact match. */
6396 && !coerce_template_template_parms
6398 targ_parms,
6399 tf_none,
6400 tparm,
6401 targs))
6402 {
6405 }
6406 }
6407 }
6408 }
6410 out:
6414 }
6416 /* Since type attributes aren't mangled, we need to strip them from
6417 template type arguments. */
6419 static tree
6421 {
6422 tree mv;
6429 {
6434 }
6436 }
6438 /* Convert the indicated template ARG as necessary to match the
6439 indicated template PARM. Returns the converted ARG, or
6440 error_mark_node if the conversion was unsuccessful. Error and
6441 warning messages are issued under control of COMPLAIN. This
6442 conversion is for the Ith parameter in the parameter list. ARGS is
6443 the full set of template arguments deduced so far. */
6445 static tree
6447 tree arg,
6448 tree args,
6449 tsubst_flags_t complain,
6451 tree in_decl)
6452 {
6453 tree orig_arg;
6454 tree val;
6459 {
6460 /* The template argument was the name of some
6461 member function. That's usually
6462 invalid, but static members are OK. In any
6463 case, grab the underlying fields/functions
6464 and issue an error later if required. */
6467 }
6475 /* When determining whether an argument pack expansion is a template,
6476 look at the pattern. */
6480 /* Deal with an injected-class-name used as a template template arg. */
6482 {
6485 {
6495 }
6496 }
6498 is_tmpl_type =
6514 {
6516 {
6520 }
6523 "to refer to a type member of a template parameter, "
6528 typename_type,
6529 complain);
6532 }
6534 {
6536 {
6538 {
6550 else
6553 }
6554 }
6556 }
6558 {
6560 {
6567 else
6570 }
6572 }
6575 {
6577 {
6581 /* The number of argument required is not known yet.
6582 Just accept it for now. */
6584 else
6585 {
6587 tree argparm;
6589 /* Strip alias templates that are equivalent to another
6590 template. */
6596 args))
6597 {
6600 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6601 TEMPLATE_DECL. */
6603 {
6608 }
6609 }
6610 else
6611 {
6613 {
6620 }
6623 }
6624 }
6625 }
6626 else
6628 /* We only form one instance of each template specialization.
6629 Therefore, if we use a non-canonical variant (i.e., a
6630 typedef), any future messages referring to the type will use
6631 the typedef, which is confusing if those future uses do not
6632 themselves also use the typedef. */
6635 }
6636 else
6637 {
6644 {
6647 else
6648 {
6649 /* Not sure if this is reachable, but it doesn't hurt
6650 to be robust. */
6653 }
6654 }
6657 /* We used to call digest_init here. However, digest_init
6658 will report errors, which we don't want when complain
6659 is zero. More importantly, digest_init will try too
6660 hard to convert things: for example, `0' should not be
6661 converted to pointer type at this point according to
6662 the standard. Accepting this is not merely an
6663 extension, since deciding whether or not these
6664 conversions can occur is part of determining which
6665 function template to call, or whether a given explicit
6666 argument specification is valid. */
6668 else
6677 {
6678 /* Strip typedefs from the SCOPE_REF. */
6681 complain);
6684 }
6685 }
6688 }
6690 /* Coerces the remaining template arguments in INNER_ARGS (from
6691 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6692 Returns the coerced argument pack. PARM_IDX is the position of this
6693 parameter in the template parameter list. ARGS is the original
6694 template argument list. */
6695 static tree
6698 tree args,
6699 tree inner_args,
6701 tree new_args,
6703 tree in_decl,
6704 tsubst_flags_t complain)
6705 {
6708 tree packed_args;
6709 tree argument_pack;
6716 {
6717 /* When the template parameter is a non-type template parameter pack
6718 or template template parameter pack whose type or template
6719 parameters use parameter packs, we know exactly how many arguments
6720 we are looking for. Build a vector of the instantiated decls for
6721 these template parameters in PACKED_PARMS. */
6722 /* We can't use make_pack_expansion here because it would interpret a
6723 _DECL as a use rather than a declaration. */
6737 /* If we're doing a partial instantiation of a member template,
6738 verify that all of the types used for the non-type
6739 template parameter pack are, in fact, valid for non-type
6740 template parameters. */
6743 {
6746 {
6750 }
6751 }
6754 }
6755 else
6758 /* Convert the remaining arguments, which will be a part of the
6759 parameter pack "parm". */
6761 {
6767 {
6768 /* Once we've packed as many args as we have types, stop. */
6772 /* We don't know how many args we have yet, just
6773 use the unconverted ones for now. */
6775 else
6777 }
6780 {
6783 }
6784 else
6787 in_decl);
6791 }
6795 {
6800 }
6805 else
6806 {
6811 }
6814 #ifdef ENABLE_CHECKING
6817 #endif
6819 }
6821 /* Returns the number of pack expansions in the template argument vector
6822 ARGS. */
6824 static int
6826 {
6831 {
6835 }
6837 }
6839 /* Convert all template arguments to their appropriate types, and
6840 return a vector containing the innermost resulting template
6841 arguments. If any error occurs, return error_mark_node. Error and
6842 warning messages are issued under control of COMPLAIN.
6844 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6845 for arguments not specified in ARGS. Otherwise, if
6846 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
6847 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
6848 USE_DEFAULT_ARGS is false, then all arguments must be specified in
6849 ARGS. */
6851 static tree
6853 tree args,
6854 tree in_decl,
6855 tsubst_flags_t complain,
6858 {
6860 tree orig_inner_args;
6861 tree inner_args;
6862 tree new_args;
6863 tree new_inner_args;
6867 /* When used as a boolean value, indicates whether this is a
6868 variadic template parameter list. Since it's an int, we can also
6869 subtract it from nparms to get the number of non-variadic
6870 parameters. */
6875 /* Likewise for parameters with default arguments. */
6883 /* Determine if there are any parameter packs or default arguments. */
6885 {
6893 }
6896 /* If there are no parameters that follow a parameter pack, we need to
6897 expand any argument packs so that we can deduce a parameter pack from
6898 some non-packed args followed by an argument pack, as in variadic85.C.
6899 If there are such parameters, we need to leave argument packs intact
6900 so the arguments are assigned properly. This can happen when dealing
6901 with a nested class inside a partial specialization of a class
6902 template, as in variadic92.C, or when deducing a template parameter pack
6903 from a sub-declarator, as in variadic114.C. */
6907 /* Count any pack expansion args. */
6913 && require_all_args
6914 && !variadic_args_p
6915 && (!use_default_args
6918 {
6920 {
6922 {
6926 }
6927 else
6933 }
6936 }
6937 /* We can't pass a pack expansion to a non-pack parameter of an alias
6938 template (DR 1430). */
6940 && variadic_args_p
6942 {
6944 {
6946 {
6952 {
6957 }
6958 }
6960 found:;
6961 }
6963 }
6965 /* We need to evaluate the template arguments, even though this
6966 template-id may be nested within a "sizeof". */
6975 {
6976 tree arg;
6977 tree parm;
6979 /* Get the Ith template parameter. */
6983 {
6986 }
6988 /* Calculate the next argument. */
6991 else
6996 {
6997 /* Some arguments will be placed in the
6998 template parameter pack PARM. */
7005 {
7006 /* We don't know how many args we have yet, just use the
7007 unconverted (and still packed) ones for now. */
7011 }
7015 /* Store this argument. */
7017 {
7018 lost++;
7019 /* We are done with all of the arguments. */
7021 }
7022 else
7023 {
7026 }
7029 }
7031 {
7033 {
7034 /* "If every valid specialization of a variadic template
7035 requires an empty template parameter pack, the template is
7036 ill-formed, no diagnostic required." So check that the
7037 pattern works with this parameter. */
7042 in_decl);
7044 {
7048 }
7050 /* Recover from missing typename. */
7054 /* We don't know how many args we have yet, just
7055 use the unconverted ones for now. */
7059 }
7060 }
7062 {
7063 /* There must be a default arg in this case. */
7066 /* The position of the first default template argument,
7067 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
7068 Record that. */
7072 }
7073 else
7077 {
7080 }
7082 /* This only occurs if there was an error in the template
7083 parameter list itself (which we would already have
7084 reported) that we are trying to recover from, e.g., a class
7085 template with a parameter list such as
7086 template<typename..., typename>. */
7088 else
7094 lost++;
7096 }
7101 {
7103 {
7108 }
7110 }
7115 #ifdef ENABLE_CHECKING
7119 #endif
7122 }
7124 /* Like coerce_template_parms. If PARMS represents all template
7125 parameters levels, this function returns a vector of vectors
7126 representing all the resulting argument levels. Note that in this
7127 case, only the innermost arguments are coerced because the
7128 outermost ones are supposed to have been coerced already.
7130 Otherwise, if PARMS represents only (the innermost) vector of
7131 parameters, this function returns a vector containing just the
7132 innermost resulting arguments. */
7134 static tree
7136 tree args,
7137 tree in_decl,
7138 tsubst_flags_t complain,
7141 {
7144 tree coerced_args;
7147 {
7149 tree level;
7155 {
7156 tree l;
7160 require_all_args,
7161 use_default_args);
7162 else
7169 }
7170 }
7171 else
7174 require_all_args,
7175 use_default_args);
7177 }
7179 /* Returns 1 if template args OT and NT are equivalent. */
7181 static int
7183 {
7190 /* For member templates */
7199 {
7216 }
7218 {
7219 /* We get here probably because we are in the middle of substituting
7220 into the pattern of a pack expansion. In that case the
7221 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
7222 interested in. So we want to use the initial pack argument for
7223 the comparison. */
7228 }
7230 {
7233 /* Don't treat an alias template specialization with dependent
7234 arguments as equivalent to its underlying type when used as a
7235 template argument; we need them to hash differently. */
7245 else
7247 }
7250 else
7252 }
7254 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
7255 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
7256 NEWARG_PTR with the offending arguments if they are non-NULL. */
7258 static int
7261 {
7274 {
7279 {
7285 }
7286 }
7288 }
7290 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
7291 of template arguments. Returns 0 otherwise. */
7293 int
7295 {
7297 }
7299 static void
7301 {
7311 /* We are called both from instantiate_decl, where we've already had a
7312 tinst_level pushed, and instantiate_template, where we haven't.
7313 Compensate. */
7324 else
7333 }
7336 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
7337 ARGLIST. Valid choices for FNS are given in the cp-tree.def
7338 documentation for TEMPLATE_ID_EXPR. */
7340 tree
7342 {
7343 tree type;
7351 {
7354 }
7357 {
7359 unknown_type_node,
7361 arglist);
7363 }
7370 }
7372 /* Within the scope of a template class S<T>, the name S gets bound
7373 (in build_self_reference) to a TYPE_DECL for the class, not a
7374 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
7375 or one of its enclosing classes, and that type is a template,
7376 return the associated TEMPLATE_DECL. Otherwise, the original
7377 DECL is returned.
7379 Also handle the case when DECL is a TREE_LIST of ambiguous
7380 injected-class-names from different bases. */
7382 tree
7384 {
7388 /* DR 176: A lookup that finds an injected-class-name (10.2
7389 [class.member.lookup]) can result in an ambiguity in certain cases
7390 (for example, if it is found in more than one base class). If all of
7391 the injected-class-names that are found refer to specializations of
7392 the same class template, and if the name is followed by a
7393 template-argument-list, the reference refers to the class template
7394 itself and not a specialization thereof, and is not ambiguous. */
7396 {
7399 {
7405 }
7408 else
7410 }
7416 }
7418 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
7419 parameters, find the desired type.
7421 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
7423 IN_DECL, if non-NULL, is the template declaration we are trying to
7424 instantiate.
7426 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
7427 the class we are looking up.
7429 Issue error and warning messages under control of COMPLAIN.
7431 If the template class is really a local class in a template
7432 function, then the FUNCTION_CONTEXT is the function in which it is
7433 being instantiated.
7435 ??? Note that this function is currently called *twice* for each
7436 template-id: the first time from the parser, while creating the
7437 incomplete type (finish_template_type), and the second type during the
7438 real instantiation (instantiate_template_class). This is surely something
7439 that we want to avoid. It also causes some problems with argument
7440 coercion (see convert_nontype_argument for more information on this). */
7442 static tree
7445 {
7447 tree t;
7450 spec_entry elt;
7451 hashval_t hash;
7454 {
7458 else
7459 {
7466 }
7469 }
7471 {
7474 /* If we are declaring a constructor, say A<T>::A<T>, we will get
7475 an implicit typename for the second A. Deal with it. */
7480 {
7483 }
7484 }
7487 {
7490 }
7492 {
7496 }
7498 {
7501 }
7503 /* Issue an error message if we didn't find a template. */
7505 {
7509 }
7512 /* Make sure it's a user visible template, if it was named by
7513 the user. */
7516 {
7518 {
7522 }
7524 }
7528 /* An alias that just changes the name of a template is equivalent to the
7529 other template, so if any of the arguments are pack expansions, strip
7530 the alias to avoid problems with a pack expansion passed to a non-pack
7531 alias template parameter (DR 1430). */
7536 {
7537 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7538 template arguments */
7540 tree parm;
7541 tree arglist2;
7542 tree outer;
7546 /* Consider an example where a template template parameter declared as
7548 template <class T, class U = std::allocator<T> > class TT
7550 The template parameter level of T and U are one level larger than
7551 of TT. To proper process the default argument of U, say when an
7552 instantiation `TT<int>' is seen, we need to build the full
7553 arguments containing {int} as the innermost level. Outer levels,
7554 available when not appearing as default template argument, can be
7555 obtained from the arguments of the enclosing template.
7557 Suppose that TT is later substituted with std::vector. The above
7558 instantiation is `TT<int, std::allocator<T> >' with TT at
7559 level 1, and T at level 2, while the template arguments at level 1
7560 becomes {std::vector} and the inner level 2 is {int}. */
7566 /* This is an argument of the current template, so we haven't set
7567 DECL_CONTEXT yet. */
7574 complain,
7584 }
7585 else
7586 {
7588 tree gen_tmpl;
7589 tree type_decl;
7597 /* An error occurred while building the template TEMPL, and a
7598 diagnostic has most certainly been emitted for that
7599 already. Let's propagate that error. */
7608 {
7609 /* We've been given an incomplete set of template arguments.
7610 For example, given:
7612 template <class T> struct S1 {
7613 template <class U> struct S2 {};
7614 template <class U> struct S2<U*> {};
7615 };
7617 we will be called with an ARGLIST of `U*', but the
7618 TEMPLATE will be `template <class T> template
7619 <class U> struct S1<T>::S2'. We must fill in the missing
7620 arguments. */
7621 arglist
7623 arglist);
7625 }
7627 /* Now we should have enough arguments. */
7630 /* From here on, we're only interested in the most general
7631 template. */
7633 /* Calculate the BOUND_ARGS. These will be the args that are
7634 actually tsubst'd into the definition to create the
7635 instantiation. */
7637 {
7638 /* We have multiple levels of arguments to coerce, at once. */
7648 {
7649 tree a;
7653 complain,
7656 else
7657 /* Outer levels should have already been coerced. */
7660 /* Don't process further if one of the levels fails. */
7662 {
7663 /* Restore the ARGLIST to its full size. */
7666 }
7670 /* We temporarily reduce the length of the ARGLIST so
7671 that coerce_template_parms will see only the arguments
7672 corresponding to the template parameters it is
7673 examining. */
7675 }
7677 /* Restore the ARGLIST to its full size. */
7681 }
7682 else
7683 arglist
7686 gen_tmpl,
7687 complain,
7692 /* We were unable to bind the arguments. */
7695 /* In the scope of a template class, explicit references to the
7696 template class refer to the type of the template, not any
7697 instantiation of it. For example, in:
7699 template <class T> class C { void f(C<T>); }
7701 the `C<T>' is just the same as `C'. Outside of the
7702 class, however, such a reference is an instantiation. */
7706 /* comp_template_args is expensive, check it last. */
7708 arglist))
7711 /* If we already have this specialization, return it. */
7722 /* If the deduced arguments are invalid, then the binding
7723 failed. */
7727 complain))
7734 {
7739 }
7749 /* Create the type. */
7751 {
7752 /* The user referred to a specialization of an alias
7753 template represented by GEN_TMPL.
7755 [temp.alias]/2 says:
7757 When a template-id refers to the specialization of an
7758 alias template, it is equivalent to the associated
7759 type obtained by substitution of its
7760 template-arguments for the template-parameters in the
7761 type-id of the alias template. */
7764 /* Note that the call above (by indirectly calling
7765 register_specialization in tsubst_decl) registers the
7766 TYPE_DECL representing the specialization of the alias
7767 template. So next time someone substitutes ARGLIST for
7768 the template parms into the alias template (GEN_TMPL),
7769 she'll get that TYPE_DECL back. */
7773 }
7775 {
7777 {
7786 }
7787 else
7788 {
7789 /* We don't want to call start_enum for this type, since
7790 the values for the enumeration constants may involve
7791 template parameters. And, no one should be interested
7792 in the enumeration constants for such a type. */
7795 }
7799 }
7801 {
7808 /* A local class. Make sure the decl gets registered properly. */
7813 /* This instantiation is another name for the primary
7814 template type. Set the TYPE_CANONICAL field
7815 appropriately. */
7818 /* Some of the template arguments require structural
7819 equality testing, so this template class requires
7820 structural equality testing. */
7822 }
7823 else
7826 /* If we called start_enum or pushtag above, this information
7827 will already be set up. */
7829 {
7836 }
7837 else
7841 {
7847 {
7850 }
7851 }
7855 {
7858 {
7861 else
7865 }
7866 }
7868 /* Let's consider the explicit specialization of a member
7869 of a class template specialization that is implicitly instantiated,
7870 e.g.:
7871 template<class T>
7872 struct S
7873 {
7874 template<class U> struct M {}; //#0
7875 };
7877 template<>
7878 template<>
7879 struct S<int>::M<char> //#1
7880 {
7881 int i;
7882 };
7883 [temp.expl.spec]/4 says this is valid.
7885 In this case, when we write:
7886 S<int>::M<char> m;
7888 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
7889 the one of #0.
7891 When we encounter #1, we want to store the partial instantiation
7892 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
7894 For all cases other than this "explicit specialization of member of a
7895 class template", we just want to store the most general template into
7896 the CLASSTYPE_TI_TEMPLATE of M.
7898 This case of "explicit specialization of member of a class template"
7899 only happens when:
7900 1/ the enclosing class is an instantiation of, and therefore not
7901 the same as, the context of the most general template, and
7902 2/ we aren't looking at the partial instantiation itself, i.e.
7903 the innermost arguments are not the same as the innermost parms of
7904 the most general template.
7906 So it's only when 1/ and 2/ happens that we want to use the partial
7907 instantiation of the member template in lieu of its most general
7908 template. */
7912 /* the enclosing class must be an instantiation... */
7915 {
7916 tree partial_inst_args;
7919 partial_inst_args =
7925 use_partial_inst_tmpl =
7926 /*...and we must not be looking at the partial instantiation
7927 itself. */
7929 partial_inst_args);
7930 }
7933 /* This case is easy; there are no member templates involved. */
7935 else
7936 {
7937 /* This is a full instantiation of a member template. Find
7938 the partial instantiation of which this is an instance. */
7940 /* Temporarily reduce by one the number of levels in the ARGLIST
7941 so as to avoid comparing the last set of arguments. */
7945 /* FOUND is either a proper class type, or an alias
7946 template specialization. In the later case, it's a
7947 TYPE_DECL, resulting from the substituting of arguments
7948 for parameters in the TYPE_DECL of the alias template
7949 done earlier. So be careful while getting the template
7950 of FOUND. */
7954 }
7964 /* Note this use of the partial instantiation so we can check it
7965 later in maybe_process_partial_specialization. */
7972 /* Now that the type has been registered on the instantiations
7973 list, we set up the enumerators. Because the enumeration
7974 constants may involve the enumeration type itself, we make
7975 sure to register the type first, and then create the
7976 constants. That way, doing tsubst_expr for the enumeration
7977 constants won't result in recursive calls here; we'll find
7978 the instantiation and exit above. */
7982 /* If the type makes use of template parameters, the
7983 code that generates debugging information will crash. */
7986 /* Possibly limit visibility based on template args. */
7993 }
7994 }
7996 /* Wrapper for lookup_template_class_1. */
7998 tree
8001 {
8002 tree ret;
8008 }
8010 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST.
8011 If the ARGLIST refers to any template parameters, the type of the
8012 expression is the unknown_type_node since the template-id could
8013 refer to an explicit or partial specialization. */
8015 tree
8017 {
8018 tree type;
8021 else
8028 }
8030 \f
8031 struct pair_fn_data
8032 {
8033 tree_fn_t fn;
8035 /* True when we should also visit template parameters that occur in
8036 non-deduced contexts. */
8039 };
8041 /* Called from for_each_template_parm via walk_tree. */
8043 static tree
8045 {
8058 {
8062 /* Fall through. */
8085 /* Since we're not going to walk subtrees, we have to do this
8086 explicitly here. */
8090 /* Fall through. */
8093 /* Check the return type. */
8098 /* Check the parameter types. Since default arguments are not
8099 instantiated until they are needed, the TYPE_ARG_TYPES may
8100 contain expressions that involve template parameters. But,
8101 no-one should be looking at them yet. And, once they're
8102 instantiated, they don't contain template parameters, so
8103 there's no point in looking at them then, either. */
8104 {
8105 tree parm;
8112 /* Since we've already handled the TYPE_ARG_TYPES, we don't
8113 want walk_tree walking into them itself. */
8115 }
8133 /* Fall through. */
8149 /* Record template parameters such as `T' inside `TT<T>'. */
8153 /* Fall through. */
8165 /* A template template parameter is encountered. */
8171 /* Already substituted template template parameter */
8194 /* If there's no type, then this thing must be some expression
8195 involving template parameters. */
8217 }
8219 /* We didn't find any template parameters we liked. */
8221 }
8223 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
8224 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
8225 call FN with the parameter and the DATA.
8226 If FN returns nonzero, the iteration is terminated, and
8227 for_each_template_parm returns 1. Otherwise, the iteration
8228 continues. If FN never returns a nonzero value, the value
8229 returned by for_each_template_parm is 0. If FN is NULL, it is
8230 considered to be the function which always returns 1.
8232 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
8233 parameters that occur in non-deduced contexts. When false, only
8234 visits those template parameters that can be deduced. */
8236 static int
8240 {
8244 /* Set up. */
8249 /* Walk the tree. (Conceptually, we would like to walk without
8250 duplicates, but for_each_template_parm_r recursively calls
8251 for_each_template_parm, so we would need to reorganize a fair
8252 bit to use walk_tree_without_duplicates, so we keep our own
8253 visited list.) */
8256 else
8259 for_each_template_parm_r,
8263 /* Clean up. */
8265 {
8268 }
8271 }
8273 /* Returns true if T depends on any template parameter. */
8275 int
8277 {
8304 else
8305 {
8308 }
8313 }
8315 /* Returns true iff current_function_decl is an incompletely instantiated
8316 template. Useful instead of processing_template_decl because the latter
8317 is set to 0 during instantiate_non_dependent_expr. */
8319 bool
8321 {
8330 }
8332 /* Returns true if T depends on any template parameter with level LEVEL. */
8334 int
8336 {
8339 }
8341 /* Returns TRUE iff INST is an instantiation we don't need to do in an
8342 ill-formed translation unit, i.e. a variable or function that isn't
8343 usable in a constant expression. */
8347 {
8351 }
8353 /* Returns TRUE iff we should refuse to instantiate DECL because it's
8354 neglectable and instantiated from within an erroneous instantiation. */
8356 static bool
8358 {
8369 }
8377 /* We're starting to instantiate D; record the template instantiation context
8378 for diagnostics and to restore it later. */
8380 bool
8382 {
8384 }
8386 /* We're starting to instantiate D; record the template instantiation context
8387 at LOC for diagnostics and to restore it later. */
8389 bool
8391 {
8395 {
8398 max_tinst_depth);
8400 }
8402 /* If the current instantiation caused problems, don't let it instantiate
8403 anything else. Do allow deduction substitution and decls usable in
8404 constant expressions. */
8421 }
8423 /* We're done instantiating this template; return to the instantiation
8424 context. */
8426 void
8428 {
8429 /* Restore the filename and line number stashed away when we started
8430 this instantiation. */
8434 }
8436 /* We're instantiating a deferred template; restore the template
8437 instantiation context in which the instantiation was requested, which
8438 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
8440 static tree
8442 {
8454 }
8456 /* Returns the TINST_LEVEL which gives the original instantiation
8457 context. */
8461 {
8467 }
8469 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
8470 vector of template arguments, as for tsubst.
8472 Returns an appropriate tsubst'd friend declaration. */
8474 static tree
8476 {
8477 tree new_friend;
8482 /* This was a friend declared with an explicit template
8483 argument list, e.g.:
8485 friend void f<>(T);
8487 to indicate that f was a template instantiation, not a new
8488 function declaration. Now, we have to figure out what
8489 instantiation of what template. */
8490 {
8492 tree new_args;
8493 tree tmpl;
8496 /* Friend functions are looked up in the containing namespace scope.
8497 We must enter that scope, to avoid finding member functions of the
8498 current class with same name. */
8513 tsk_none);
8515 }
8519 /* The NEW_FRIEND will look like an instantiation, to the
8520 compiler, but is not an instantiation from the point of view of
8521 the language. For example, we might have had:
8523 template <class T> struct S {
8524 template <class U> friend void f(T, U);
8525 };
8527 Then, in S<int>, template <class U> void f(int, U) is not an
8528 instantiation of anything. */
8534 {
8538 }
8540 /* The mangled name for the NEW_FRIEND is incorrect. The function
8541 is not a template instantiation and should not be mangled like
8542 one. Therefore, we forget the mangling here; we'll recompute it
8543 later if we need it. */
8545 {
8548 }
8551 {
8552 tree old_decl;
8553 tree new_friend_template_info;
8554 tree new_friend_result_template_info;
8555 tree ns;
8558 /* We must save some information from NEW_FRIEND before calling
8559 duplicate decls since that function will free NEW_FRIEND if
8560 possible. */
8562 new_friend_is_defn =
8567 {
8568 /* This declaration is a `primary' template. */
8571 new_friend_result_template_info
8573 }
8574 else
8577 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8581 /* Inside pushdecl_namespace_level, we will push into the
8582 current namespace. However, the friend function should go
8583 into the namespace of the template. */
8593 {
8594 /* This new friend declaration matched an existing
8595 declaration. For example, given:
8597 template <class T> void f(T);
8598 template <class U> class C {
8599 template <class T> friend void f(T) {}
8600 };
8602 the friend declaration actually provides the definition
8603 of `f', once C has been instantiated for some type. So,
8604 old_decl will be the out-of-class template declaration,
8605 while new_friend is the in-class definition.
8607 But, if `f' was called before this point, the
8608 instantiation of `f' will have DECL_TI_ARGS corresponding
8609 to `T' but not to `U', references to which might appear
8610 in the definition of `f'. Previously, the most general
8611 template for an instantiation of `f' was the out-of-class
8612 version; now it is the in-class version. Therefore, we
8613 run through all specialization of `f', adding to their
8614 DECL_TI_ARGS appropriately. In particular, they need a
8615 new set of outer arguments, corresponding to the
8616 arguments for this class instantiation.
8618 The same situation can arise with something like this:
8620 friend void f(int);
8621 template <class T> class C {
8622 friend void f(T) {}
8623 };
8625 when `C<int>' is instantiated. Now, `f(int)' is defined
8626 in the class. */
8629 /* On the other hand, if the in-class declaration does
8630 *not* provide a definition, then we don't want to alter
8631 existing definitions. We can just leave everything
8632 alone. */
8633 ;
8634 else
8635 {
8639 /* Overwrite whatever template info was there before, if
8640 any, with the new template information pertaining to
8641 the declaration. */
8645 {
8646 /* We should have called reregister_specialization in
8647 duplicate_decls. */
8652 /* Instantiate it if the global has already been used. */
8656 }
8657 else
8658 {
8659 tree t;
8661 /* Indicate that the old function template is a partial
8662 instantiation. */
8670 /* Reassign any specializations already in the hash table
8671 to the new more general template, and add the
8672 additional template args. */
8676 {
8678 spec_entry elt;
8690 register_specialization
8693 }
8695 }
8696 }
8698 /* The information from NEW_FRIEND has been merged into OLD_DECL
8699 by duplicate_decls. */
8701 }
8702 }
8703 else
8704 {
8708 /* In the code
8709 template <class T> class C {
8710 template <class U> friend void C1<U>::f (); // case 1
8711 friend void C2<T>::f (); // case 2
8712 };
8713 we only need to make sure CONTEXT is a complete type for
8714 case 2. To distinguish between the two cases, we note that
8715 CONTEXT of case 1 remains dependent type after tsubst while
8716 this isn't true for case 2. */
8726 {
8728 /* do_friend adds the TEMPLATE_DECL for any member friend
8729 template even if it isn't a member template, i.e.
8730 template <class T> friend A<T>::f();
8731 Look through it in that case. */
8735 /* Check to see that the declaration is really present, and,
8736 possibly obtain an improved declaration. */
8741 }
8742 }
8745 }
8747 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8748 template arguments, as for tsubst.
8750 Returns an appropriate tsubst'd friend type or error_mark_node on
8751 failure. */
8753 static tree
8755 {
8756 tree friend_type;
8757 tree tmpl;
8758 tree context;
8761 {
8764 }
8769 {
8772 else
8774 }
8776 /* Look for a class template declaration. We look for hidden names
8777 because two friend declarations of the same template are the
8778 same. For example, in:
8780 struct A {
8781 template <typename> friend class F;
8782 };
8783 template <typename> struct B {
8784 template <typename> friend class F;
8785 };
8787 both F templates are the same. */
8791 /* But, if we don't find one, it might be because we're in a
8792 situation like this:
8794 template <class T>
8795 struct S {
8796 template <class U>
8797 friend struct S;
8798 };
8800 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8801 for `S<int>', not the TEMPLATE_DECL. */
8803 {
8806 }
8809 {
8810 /* The friend template has already been declared. Just
8811 check to see that the declarations match, and install any new
8812 default parameters. We must tsubst the default parameters,
8813 of course. We only need the innermost template parameters
8814 because that is all that redeclare_class_template will look
8815 at. */
8818 {
8819 tree parms;
8820 location_t saved_input_location;
8829 }
8832 }
8833 else
8834 {
8835 /* The friend template has not already been declared. In this
8836 case, the instantiation of the template class will cause the
8837 injection of this template into the global scope. */
8842 /* The new TMPL is not an instantiation of anything, so we
8843 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
8844 the new type because that is supposed to be the corresponding
8845 template decl, i.e., TMPL. */
8852 /* Inject this template into the global scope. */
8854 }
8857 {
8860 else
8862 }
8865 }
8867 /* Returns zero if TYPE cannot be completed later due to circularity.
8868 Otherwise returns one. */
8870 static int
8872 {
8882 else
8884 }
8888 /* Apply any attributes which had to be deferred until instantiation
8889 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
8890 ARGS, COMPLAIN, IN_DECL are as tsubst. */
8892 static void
8895 {
8897 tree t;
8902 {
8906 }
8909 {
8913 }
8914 else
8918 {
8923 {
8926 {
8933 {
8940 clauses
8944 else
8946 }
8947 /* If the first attribute argument is an identifier, don't
8948 pass it through tsubst. Attributes like mode, format,
8949 cleanup and several target specific attributes expect it
8950 unmodified. */
8953 {
8954 tree chain
8956 in_decl,
8961 chain);
8962 }
8963 else
8969 }
8970 else
8972 }
8975 }
8976 }
8978 /* Perform (or defer) access check for typedefs that were referenced
8979 from within the template TMPL code.
8980 This is a subroutine of instantiate_decl and instantiate_class_template.
8981 TMPL is the template to consider and TARGS is the list of arguments of
8982 that template. */
8984 static void
8986 {
8987 location_t saved_location;
8998 {
9010 /* Make access check error messages point to the location
9011 of the use of the typedef. */
9015 tf_warning_or_error);
9016 }
9018 }
9020 static tree
9022 {
9024 tree typedecl;
9025 tree pbinfo;
9026 tree base_list;
9028 tree fn_context;
9037 /* Figure out which template is being instantiated. */
9041 /* Determine what specialization of the original template to
9042 instantiate. */
9045 {
9048 }
9050 {
9051 /* This TYPE is actually an instantiation of a partial
9052 specialization. We replace the innermost set of ARGS with
9053 the arguments appropriate for substitution. For example,
9054 given:
9056 template <class T> struct S {};
9057 template <class T> struct S<T*> {};
9059 and supposing that we are instantiating S<int*>, ARGS will
9060 presently be {int*} -- but we need {int}. */
9063 }
9064 else
9065 {
9068 }
9070 /* If the template we're instantiating is incomplete, then clearly
9071 there's nothing we can do. */
9075 /* If we've recursively instantiated too many templates, stop. */
9079 /* Now we're really doing the instantiation. Mark the type as in
9080 the process of being defined. */
9083 /* We may be in the middle of deferred access check. Disable
9084 it now. */
9088 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
9093 /* Use #pragma pack from the template context. */
9099 /* Set the input location to the most specialized template definition.
9100 This is needed if tsubsting causes an error. */
9112 {
9115 /* Adjust visibility for template arguments. */
9117 }
9123 /* We should never instantiate a nested class before its enclosing
9124 class; we need to look up the nested class by name before we can
9125 instantiate it, and that lookup should instantiate the enclosing
9126 class. */
9132 {
9133 tree pbase_binfo;
9134 tree pushed_scope;
9137 /* We must enter the scope containing the type, as that is where
9138 the accessibility of types named in dependent bases are
9139 looked up from. */
9142 /* Substitute into each of the bases to determine the actual
9143 basetypes. */
9145 {
9146 tree base;
9152 {
9153 expanded_bases =
9160 }
9163 {
9165 /* Extract the already-expanded base class. */
9167 else
9168 /* Substitute to figure out the base class. */
9170 NULL_TREE);
9178 }
9179 }
9181 /* The list is now in reverse order; correct that. */
9186 }
9187 /* Now call xref_basetypes to set up all the base-class
9188 information. */
9196 /* Now that our base classes are set up, enter the scope of the
9197 class, so that name lookups into base classes, etc. will work
9198 correctly. This is precisely analogous to what we do in
9199 begin_class_definition when defining an ordinary non-template
9200 class, except we also need to push the enclosing classes. */
9203 /* Now members are processed in the order of declaration. */
9206 {
9210 {
9212 {
9213 /* Build new CLASSTYPE_NESTED_UTDS. */
9215 tree newtag;
9221 /* If the member is a class template, then -- even after
9222 substitution -- there may be dependent types in the
9223 template argument list for the class. We increment
9224 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
9225 that function will assume that no types are dependent
9226 when outside of a template. */
9236 {
9240 /* Unfortunately, lookup_template_class sets
9241 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
9242 instantiation (i.e., for the type of a member
9243 template class nested within a template class.)
9244 This behavior is required for
9245 maybe_process_partial_specialization to work
9246 correctly, but is not accurate in this case;
9247 the TAG is not an instantiation of anything.
9248 (The corresponding TEMPLATE_DECL is an
9249 instantiation, but the TYPE is not.) */
9252 /* Now, we call pushtag to put this NEWTAG into the scope of
9253 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
9254 pushtag calling push_template_decl. We don't have to do
9255 this for enums because it will already have been done in
9256 tsubst_enum. */
9260 }
9261 }
9263 {
9264 /* Build new TYPE_METHODS. */
9265 tree r;
9274 /* Instantiate members marked with attribute used. */
9280 }
9283 /* A closure type for a lambda in a default argument for a
9284 member template. Ignore it; it will be instantiated with
9286 else
9287 {
9288 /* Build new TYPE_FIELDS. */
9290 {
9291 tree condition;
9294 condition =
9304 }
9306 {
9307 tree r;
9311 /* The file and line for this declaration, to
9312 assist in error message reporting. Since we
9313 called push_tinst_level above, we don't need to
9314 restore these. */
9324 {
9325 /* A capture pack became multiple fields. */
9328 }
9331 {
9335 {
9336 /* In [temp.inst]:
9338 [t]he initialization (and any associated
9339 side-effects) of a static data member does
9340 not occur unless the static data member is
9341 itself used in a way that requires the
9342 definition of the static data member to
9343 exist.
9345 Therefore, we do not substitute into the
9346 initialized for the static data member here. */
9347 finish_static_data_member_decl
9353 /* Instantiate members marked with attribute used. */
9356 }
9358 {
9359 /* Determine whether R has a valid type and can be
9360 completed later. If R is invalid, then its type
9361 is replaced by error_mark_node. */
9367 {
9370 }
9371 }
9373 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
9374 such a thing will already have been added to the field
9375 list by tsubst_enum in finish_member_declaration in the
9376 CLASSTYPE_NESTED_UTDS case above. */
9380 {
9383 }
9384 }
9385 }
9386 }
9387 }
9388 else
9389 {
9392 {
9393 /* Build new CLASSTYPE_FRIEND_CLASSES. */
9399 {
9400 /* template <class T> friend class C; */
9403 }
9405 {
9406 /* template <class T> friend class C::D; */
9412 }
9415 {
9416 /* This could be either
9418 friend class T::C;
9420 when dependent_type_p is false or
9422 template <class U> friend class T::C;
9424 otherwise. */
9427 /* Bump processing_template_decl for correct
9428 dependent_type_p calculation. */
9433 }
9436 {
9437 /* friend class C;
9439 where C hasn't been declared yet. Let's lookup name
9440 from namespace scope directly, bypassing any name that
9441 come from dependent base class. */
9444 /* The call to xref_tag_from_type does injection for friend
9445 classes. */
9447 friend_type =
9451 }
9453 /* friend class C<T>; */
9456 /* Otherwise it's
9458 friend class C;
9460 where C is already declared or
9462 friend class C<int>;
9464 We don't have to do anything in these cases. */
9467 /* Trick make_friend_class into realizing that the friend
9468 we're adding is a template, not an ordinary class. It's
9469 important that we use make_friend_class since it will
9470 perform some error-checking and output cross-reference
9471 information. */
9479 }
9480 else
9481 {
9482 /* Build new DECL_FRIENDLIST. */
9483 tree r;
9485 /* The file and line for this declaration, to
9486 assist in error message reporting. Since we
9487 called push_tinst_level above, we don't need to
9488 restore these. */
9492 {
9495 }
9500 {
9503 }
9504 }
9505 }
9506 }
9509 {
9512 {
9517 /* We need to instantiate the capture list from the template
9518 after we've instantiated the closure members, but before we
9519 consider adding the conversion op. Also keep any captures
9520 that may have been added during instantiation of the op(). */
9522 tree tmpl_cap
9531 }
9532 else
9534 }
9536 /* Set the file and line number information to whatever is given for
9537 the class itself. This puts error messages involving generated
9538 implicit functions at a predictable point, and the same point
9539 that would be used for non-template classes. */
9546 /* We don't instantiate default arguments for member functions. 14.7.1:
9548 The implicit instantiation of a class template specialization causes
9549 the implicit instantiation of the declarations, but not of the
9550 definitions or default arguments, of the class member functions,
9551 member classes, static data members and member templates.... */
9553 /* Some typedefs referenced from within the template code need to be access
9554 checked at template instantiation time, i.e now. These types were
9555 added to the template at parsing time. Let's get those and perform
9556 the access checks then. */
9566 /* The vtable for a template class can be emitted in any translation
9567 unit in which the class is instantiated. When there is no key
9568 method, however, finish_struct_1 will already have added TYPE to
9569 the keyed_classes list. */
9574 }
9576 /* Wrapper for instantiate_class_template_1. */
9578 tree
9580 {
9581 tree ret;
9586 }
9588 static tree
9590 {
9591 tree r;
9597 else
9598 {
9605 }
9607 }
9609 /* Given a function parameter pack TMPL_PARM and some function parameters
9610 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
9611 and set *SPEC_P to point at the next point in the list. */
9613 static tree
9615 {
9616 /* Collect all of the extra "packed" parameters into an
9617 argument pack. */
9618 tree parmvec;
9619 tree parmtypevec;
9630 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
9635 {
9638 }
9640 /* Build the argument packs. */
9647 }
9649 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9650 NONTYPE_ARGUMENT_PACK. */
9652 static tree
9654 {
9656 }
9658 /* Return true iff the Ith element of the argument pack ARG_PACK is a
9659 pack expansion. */
9661 static bool
9663 {
9668 }
9671 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
9673 static tree
9675 {
9682 }
9684 /* This is a subroutine of tsubst_pack_expansion.
9686 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
9687 mechanism to store the (non complete list of) arguments of the
9688 substitution and return a non substituted pack expansion, in order
9689 to wait for when we have enough arguments to really perform the
9690 substitution. */
9692 static bool
9696 {
9697 /* If one pack has an expansion and another pack has a normal
9698 argument or if one pack has an empty argument and an another
9699 one hasn't then tsubst_pack_expansion cannot perform the
9700 substitution and need to fall back on the
9701 PACK_EXPANSION_EXTRA mechanism. */
9709 {
9712 parm_pack;
9714 {
9719 else
9721 }
9725 }
9727 }
9729 /* [temp.variadic]/6 says that:
9731 The instantiation of a pack expansion [...]
9732 produces a list E1,E2, ..., En, where N is the number of elements
9733 in the pack expansion parameters.
9735 This subroutine of tsubst_pack_expansion produces one of these Ei.
9737 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
9738 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
9739 PATTERN, and each TREE_VALUE is its corresponding argument pack.
9740 INDEX is the index 'i' of the element Ei to produce. ARGS,
9741 COMPLAIN, and IN_DECL are the same parameters as for the
9742 tsubst_pack_expansion function.
9744 The function returns the resulting Ei upon successful completion,
9745 or error_mark_node.
9747 Note that this function possibly modifies the ARGS parameter, so
9748 it's the responsibility of the caller to restore it. */
9750 static tree
9752 tree parm_packs,
9754 tree args /* This parm gets
9756 tsubst_flags_t complain,
9757 tree in_decl)
9758 {
9759 tree t;
9762 /* For each parameter pack, change the substitution of the parameter
9763 pack to the ith argument in its argument pack, then expand the
9764 pattern. */
9766 {
9771 ith_elem_is_expansion |=
9774 /* Select the Ith argument from the pack. */
9777 {
9779 {
9783 }
9784 else
9786 }
9787 else
9788 {
9793 {
9795 /* Update the corresponding argument. */
9797 }
9798 else
9799 /* Re-use the ARGUMENT_PACK_SELECT. */
9801 }
9803 }
9805 /* Substitute into the PATTERN with the (possibly altered)
9806 arguments. */
9808 /* Expanding a fixed parameter pack from
9809 coerce_template_parameter_pack. */
9814 else
9817 /* If the Ith argument pack element is a pack expansion, then
9818 the Ith element resulting from the substituting is going to
9819 be a pack expansion as well. */
9824 }
9826 /* Substitute ARGS into T, which is an pack expansion
9827 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
9828 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
9829 (if only a partial substitution could be performed) or
9830 ERROR_MARK_NODE if there was an error. */
9831 tree
9833 tree in_decl)
9834 {
9835 tree pattern;
9839 tree result;
9847 /* Add in any args remembered from an earlier partial instantiation. */
9852 /* Determine the argument packs that will instantiate the parameter
9853 packs used in the expansion expression. While we're at it,
9854 compute the number of arguments to be expanded and make sure it
9855 is consistent. */
9858 {
9865 {
9869 else
9872 }
9874 {
9877 else
9878 {
9879 /* We can't rely on local_specializations for a parameter
9880 name used later in a function declaration (such as in a
9881 late-specified return type). Even if it exists, it might
9882 have the wrong value for a recursive call. Just make a
9883 dummy decl, since it's only used for its type. */
9886 /* Partial instantiation of the parm_pack, we can't build
9887 up an argument pack yet. */
9889 else
9892 }
9893 }
9896 else
9897 {
9903 }
9910 /* This can only happen if we forget to expand an argument
9911 pack somewhere else. Just return an error, silently. */
9912 {
9916 }
9919 {
9923 /* Don't bother trying to do a partial substitution with
9924 incomplete packs; we'll try again after deduction. */
9931 {
9937 pattern);
9938 else
9941 pattern);
9943 }
9945 /* Keep track of the parameter packs and their corresponding
9946 argument packs. */
9949 }
9950 else
9951 {
9952 /* We can't substitute for this parameter pack. We use a flag as
9953 well as the missing_level counter because function parameter
9954 packs don't have a level. */
9956 }
9957 }
9959 /* If the expansion is just T..., return the matching argument pack. */
9962 {
9967 /* Otherwise use the normal path so we get convert_from_reference. */
9968 }
9970 /* We cannot expand this expansion expression, because we don't have
9971 all of the argument packs we need. */
9973 {
9974 /* We got some full packs, but we can't substitute them in until we
9975 have values for all the packs. So remember these until then. */
9980 }
9982 {
9983 /* There were no real arguments, we're just replacing a parameter
9984 pack with another version of itself. Substitute into the
9985 pattern and return a PACK_EXPANSION_*. The caller will need to
9986 deal with that. */
9990 else
9994 }
9999 {
10000 /* We're in a late-specified return type, so create our own local
10001 specializations map; the current map is either NULL or (in the
10002 case of recursive unification) might have bindings that we don't
10003 want to use or alter. */
10006 }
10008 /* For each argument in each argument pack, substitute into the
10009 pattern. */
10012 {
10014 i,
10016 in_decl);
10019 {
10022 }
10023 }
10025 /* Update ARGS to restore the substitution from parameter packs to
10026 their argument packs. */
10028 {
10034 else
10035 {
10043 /* Update the corresponding argument. */
10047 else
10049 }
10050 }
10053 {
10056 }
10059 }
10061 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
10062 TMPL. We do this using DECL_PARM_INDEX, which should work even with
10063 parameter packs; all parms generated from a function parameter pack will
10064 have the same DECL_PARM_INDEX. */
10066 tree
10068 {
10070 tree patparm;
10073 {
10079 }
10080 else
10081 {
10086 }
10089 }
10091 /* Substitute ARGS into the vector or list of template arguments T. */
10093 static tree
10095 {
10107 {
10109 tree new_arg;
10114 {
10115 /* Substitute into an expansion expression. */
10119 /* Add to the expanded length adjustment the number of
10120 expanded arguments. We subtract one from this
10121 measurement, because the argument pack expression
10122 itself is already counted as 1 in
10123 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
10124 the argument pack is empty. */
10126 }
10128 {
10129 /* Substitute into each of the arguments. */
10135 new_arg,
10149 }
10150 }
10151 else
10160 }
10165 /* Make space for the expanded arguments coming from template
10166 argument packs. */
10168 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
10169 arguments for a member template.
10170 In that case each TREE_VEC in ORIG_T represents a level of template
10171 arguments, and ORIG_T won't carry any non defaulted argument count.
10172 It will rather be the nested TREE_VECs that will carry one.
10173 In other words, ORIG_T carries a non defaulted argument count only
10174 if it doesn't contain any nested TREE_VEC. */
10176 {
10180 }
10182 {
10186 {
10189 /* Now expand the template argument pack "in place". */
10192 }
10193 else
10194 {
10196 out++;
10197 }
10198 }
10201 }
10203 /* Return the result of substituting ARGS into the template parameters
10204 given by PARMS. If there are m levels of ARGS and m + n levels of
10205 PARMS, then the result will contain n levels of PARMS. For
10206 example, if PARMS is `template <class T> template <class U>
10207 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
10208 result will be `template <int*, double, class V>'. */
10210 static tree
10212 {
10216 /* When substituting into a template, we must set
10217 PROCESSING_TEMPLATE_DECL as the template parameters may be
10218 dependent if they are based on one-another, and the dependency
10219 predicates are short-circuit outside of templates. */
10226 {
10227 tree new_vec =
10232 {
10233 tree tuple;
10245 }
10251 }
10256 }
10258 /* Return the result of substituting ARGS into one template parameter
10259 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
10260 parameter and which TREE_PURPOSE is the default argument of the
10261 template parameter. */
10263 static tree
10265 {
10286 }
10288 /* Substitute the ARGS into the indicated aggregate (or enumeration)
10289 type T. If T is not an aggregate or enumeration type, it is
10290 handled as if by tsubst. IN_DECL is as for tsubst. If
10291 ENTERING_SCOPE is nonzero, T is the context for a template which
10292 we are presently tsubst'ing. Return the substituted value. */
10294 static tree
10296 tree args,
10297 tsubst_flags_t complain,
10298 tree in_decl,
10300 {
10305 {
10310 /* Else fall through. */
10314 {
10315 tree argvec;
10316 tree context;
10317 tree r;
10321 /* In "sizeof(X<I>)" we need to evaluate "I". */
10327 /* First, determine the context for the type we are looking
10328 up. */
10331 {
10334 /* If context is a nested class inside a class template,
10335 it may still need to be instantiated (c++/33959). */
10337 }
10339 /* Then, figure out what arguments are appropriate for the
10340 type we are trying to find. For example, given:
10342 template <class T> struct S;
10343 template <class T, class U> void f(T, U) { S<U> su; }
10345 and supposing that we are instantiating f<int, double>,
10346 then our ARGS will be {int, double}, but, when looking up
10347 S we only want {double}. */
10352 else
10353 {
10357 }
10363 }
10364 else
10365 /* This is not a template type, so there's nothing to do. */
10370 }
10371 }
10373 /* Substitute into the default argument ARG (a default argument for
10374 FN), which has the indicated TYPE. */
10376 tree
10378 {
10383 /* This can happen in invalid code. */
10387 /* This default argument came from a template. Instantiate the
10388 default argument here, not in tsubst. In the case of
10389 something like:
10391 template <class T>
10392 struct S {
10393 static T t();
10394 void f(T = t());
10395 };
10397 we must be careful to do name lookup in the scope of S<T>,
10398 rather than in the current class. */
10400 /* The "this" pointer is not valid in a default argument. */
10402 {
10407 }
10410 /* The default argument expression may cause implicitly defined
10411 member functions to be synthesized, which will result in garbage
10412 collection. We must treat this situation as if we were within
10413 the body of function so as to avoid collecting live data on the
10414 stack. */
10422 /* Restore the "this" pointer. */
10424 {
10427 }
10434 /* Make sure the default argument is reasonable. */
10440 }
10442 /* Substitute into all the default arguments for FN. */
10444 static void
10446 {
10447 tree arg;
10448 tree tmpl_args;
10452 /* If this function is not yet instantiated, we certainly don't need
10453 its default arguments. */
10456 /* Don't do this again for clones. */
10461 arg;
10467 complain);
10468 }
10470 /* Substitute the ARGS into the T, which is a _DECL. Return the
10471 result of the substitution. Issue error and warning messages under
10472 control of COMPLAIN. */
10474 static tree
10476 {
10477 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
10478 location_t saved_loc;
10483 /* Set the filename and linenumber to improve error-reporting. */
10488 {
10490 {
10491 /* We can get here when processing a member function template,
10492 member class template, or template template parameter. */
10494 tree spec;
10495 tree tmpl_args;
10496 tree full_args;
10499 {
10500 /* Template template parameter is treated here. */
10504 /* If we get a real template back, return it. This can happen in
10505 the context of most_specialized_class. */
10517 complain);
10520 }
10522 /* We might already have an instance of this template.
10523 The ARGS are for the surrounding class type, so the
10524 full args contain the tsubst'd args for the context,
10525 plus the innermost args from the template decl. */
10529 /* Because this is a template, the arguments will still be
10530 dependent, even after substitution. If
10531 PROCESSING_TEMPLATE_DECL is not set, the dependency
10532 predicates will short-circuit. */
10540 /* If this is a default template template argument,
10541 tsubst might not have changed anything. */
10548 {
10551 }
10553 /* Make a new template decl. It will be similar to the
10554 original, but will record the current template arguments.
10555 We also create a new function declaration, which is just
10556 like the old one, but points to this new template, rather
10557 than the old one. */
10566 {
10567 tree new_type;
10575 /* For a partial specialization, we need to keep pointing to
10576 the primary template. */
10582 }
10583 else
10584 {
10585 tree new_decl;
10597 }
10603 /* The template parameters for this new template are all the
10604 template parameters for the old template, except the
10605 outermost level of parameters. */
10608 complain);
10614 /* Record this non-type partial instantiation. */
10618 }
10622 {
10623 tree ctx;
10626 tree gen_tmpl;
10627 tree type;
10632 /* Nobody should be tsubst'ing into non-template functions. */
10636 {
10637 tree spec;
10640 /* If T is not dependent, just return it. We have to
10641 increment PROCESSING_TEMPLATE_DECL because
10642 value_dependent_expression_p assumes that nothing is
10643 dependent when PROCESSING_TEMPLATE_DECL is zero. */
10650 /* Calculate the most general template of which R is a
10651 specialization, and the complete set of arguments used to
10652 specialize R. */
10655 (DECL_TEMPLATE_RESULT
10661 /* Check to see if we already have this specialization. */
10666 {
10669 }
10671 /* We can see more levels of arguments than parameters if
10672 there was a specialization of a member template, like
10673 this:
10675 template <class T> struct S { template <class U> void f(); }
10676 template <> template <class U> void S<int>::f(U);
10678 Here, we'll be substituting into the specialization,
10679 because that's where we can find the code we actually
10680 want to generate, but we'll have enough arguments for
10681 the most general template.
10683 We also deal with the peculiar case:
10685 template <class T> struct S {
10686 template <class U> friend void f();
10687 };
10688 template <class U> void f() {}
10689 template S<int>;
10690 template void f<double>();
10692 Here, the ARGS for the instantiation of will be {int,
10693 double}. But, we only need as many ARGS as there are
10694 levels of template parameters in CODE_PATTERN. We are
10695 careful not to get fooled into reducing the ARGS in
10696 situations like:
10698 template <class T> struct S { template <class U> void f(U); }
10699 template <class T> template <> void S<T>::f(int) {}
10701 which we can spot because the pattern will be a
10702 specialization in this case. */
10704 parms_depth =
10709 }
10710 else
10711 {
10712 /* This special case arises when we have something like this:
10714 template <class T> struct S {
10715 friend void f<int>(int, double);
10716 };
10718 Here, the DECL_TI_TEMPLATE for the friend declaration
10719 will be an IDENTIFIER_NODE. We are being called from
10720 tsubst_friend_function, and we want only to create a
10721 new decl (R) with appropriate types so that we can call
10722 determine_specialization. */
10724 }
10727 {
10730 else
10734 }
10735 else
10736 {
10739 }
10744 /* If we hit excessive deduction depth, the type is bogus even if
10745 it isn't error_mark_node, so don't build a decl. */
10749 /* We do NOT check for matching decls pushed separately at this
10750 point, as they may not represent instantiations of this
10751 template, and in any case are considered separate under the
10752 discrete model. */
10756 /* Clear out the mangled name and RTL for the instantiation. */
10759 /* Leave DECL_INITIAL set on deleted instantiations. */
10764 /* OpenMP UDRs have the only argument a reference to the declared
10765 type. We want to diagnose if the declared type is a reference,
10766 which is invalid, but as references to references are usually
10767 quietly merged, diagnose it here. */
10769 {
10770 tree argtype
10775 "reference type %qT in "
10779 argtype);
10780 }
10783 /* Type-conversion operator. Reconstruct the name, in
10784 case it's the name of one of the template's parameters. */
10794 /* If this is an instantiation of a function with internal
10795 linkage, we already know what object file linkage will be
10796 assigned to the instantiation. */
10805 /* We'll re-clone as appropriate in instantiate_template. */
10808 /* If we aren't complaining now, return on error before we register
10809 the specialization so that we'll complain eventually. */
10815 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
10816 this in the special friend case mentioned above where
10817 GEN_TMPL is NULL. */
10819 {
10824 tree new_r
10827 /* We instantiated this while substituting into
10828 the type earlier (template/friend54.C). */
10831 /* We're not supposed to instantiate default arguments
10832 until they are called, for a template. But, for a
10833 declaration like:
10835 template <class T> void f ()
10836 { extern void g(int i = T()); }
10838 we should do the substitution when the template is
10839 instantiated. We handle the member function case in
10840 instantiate_class_template since the default arguments
10841 might refer to other members of the class. */
10846 }
10847 else
10850 /* Copy the list of befriending classes. */
10854 {
10858 in_decl);
10859 }
10862 {
10868 /* If this is an instantiation of a member template, clone it.
10869 If it isn't, that'll be handled by
10870 clone_constructors_and_destructors. */
10873 }
10884 /* Possibly limit visibility based on template args. */
10887 {
10891 }
10899 }
10903 {
10911 {
10912 /* If there is a local specialization that isn't a
10913 parameter pack, it means that we're doing a "simple"
10914 substitution from inside tsubst_pack_expansion. Just
10915 return the local specialization (which will be a single
10916 parm). */
10923 /* Expand the TYPE_PACK_EXPANSION that provides the types for
10924 the parameters in this function parameter pack. */
10928 {
10931 /* Zero-length parameter packs are boring. Just substitute
10932 into the chain. */
10936 }
10937 else
10938 {
10939 /* All we did was update the type. Make a note of that. */
10942 }
10943 }
10945 /* Loop through all of the parameters we'll build. When T is
10946 a function parameter pack, LEN is the number of expanded
10947 types in EXPANDED_TYPES; otherwise, LEN is 1. */
10950 {
10957 /* We're on the Ith parameter of the function parameter
10958 pack. */
10959 {
10960 /* Get the Ith type. */
10963 /* Rename the parameter to include the index. */
10966 }
10968 /* We're dealing with a normal parameter. */
10976 {
10979 else
10982 }
10992 /* Keep track of the first new parameter we
10993 generate. That's what will be returned to the
10994 caller. */
10998 /* Build a proper chain of parameters when substituting
10999 into a function parameter pack. */
11002 }
11004 /* If cp_unevaluated_operand is set, we're just looking for a
11005 single dummy parameter, so don't keep going. */
11010 /* FIRST_R contains the start of the chain we've built. */
11012 }
11016 {
11023 {
11024 /* This field is a lambda capture pack. Return a TREE_VEC of
11025 the expanded fields to instantiate_class_template_1 and
11026 store them in the specializations hash table as a
11027 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
11031 {
11034 }
11035 else
11036 {
11037 /* All we did was update the type. Make a note of that. */
11040 }
11041 }
11044 {
11047 {
11051 }
11061 /* For bit-fields, DECL_INITIAL gives the number of bits. For
11062 non-bit-fields DECL_INITIAL is a non-static data member
11063 initializer, which gets deferred instantiation. */
11069 {
11070 /* Set up DECL_TEMPLATE_INFO so that we can get at the
11071 NSDMI in perform_member_init. Still set DECL_INITIAL
11072 so that we know there is one. */
11077 }
11078 /* We don't have to set DECL_CONTEXT here; it is set by
11079 finish_member_declaration. */
11087 }
11090 {
11098 }
11099 }
11103 /* We reach here only for member using decls. We also need to check
11104 uses_template_parms because DECL_DEPENDENT_P is not set for a
11105 using-declaration that designates a member of the current
11106 instantiation (c++/53549). */
11109 {
11116 else
11117 {
11120 }
11121 }
11122 else
11123 {
11126 }
11131 {
11134 tree spec;
11136 tree ctx;
11145 {
11146 /* If this is the canonical decl, we don't have to
11147 mess with instantiations, and often we can't (for
11148 typename, template type parms and such). Note that
11149 TYPE_NAME is not correct for the above test if
11150 we've copied the type for a typedef. */
11156 }
11158 /* Check to see if we already have the specialization we
11159 need. */
11162 {
11163 /* T is a static data member or namespace-scope entity.
11164 We have to substitute into namespace-scope variables
11165 (even though such entities are never templates) because
11166 of cases like:
11168 template <class T> void f() { extern T t; }
11170 where the entity referenced is not known until
11171 instantiation time. */
11175 {
11177 complain,
11179 /* If CTX is unchanged, then T is in fact the
11180 specialization we want. That situation occurs when
11181 referencing a static data member within in its own
11182 class. We can use pointer equality, rather than
11183 same_type_p, because DECL_CONTEXT is always
11184 canonical... */
11186 /* ... unless T is a member template; in which
11187 case our caller can be willing to create a
11188 specialization of that template represented
11189 by T. */
11193 }
11196 {
11204 }
11205 }
11206 else
11207 {
11208 /* A local variable. */
11210 /* Subsequent calls to pushdecl will fill this in. */
11213 }
11214 /* If we already have the specialization we need, there is
11215 nothing more to do. */
11217 {
11220 }
11222 /* Create a new node for the specialization we need. */
11225 {
11228 else
11235 }
11237 {
11238 /* Even if the original location is out of scope, the
11239 newly substituted one is not. */
11246 {
11247 /* It may seem that this case cannot occur, since:
11249 typedef void f();
11250 void g() { f x; }
11252 declares a function, not a variable. However:
11254 typedef void f();
11255 template <typename T> void g() { T t; }
11256 template void g<f>();
11258 is an attempt to declare a variable with function
11259 type. */
11261 /* R is not yet sufficiently initialized, so we
11262 just use its name. */
11265 }
11267 /* Wait until cp_finish_decl to set this again, to handle
11268 circular dependency (template/instantiate6.C). */
11273 {
11278 {
11281 }
11283 }
11286 }
11292 /* Clear out the mangled name and RTL for the instantiation. */
11296 /* The initializer must not be expanded until it is required;
11297 see [temp.inst]. */
11303 {
11304 /* Possibly limit visibility based on template args. */
11307 {
11311 }
11313 }
11316 {
11317 /* A static data member declaration is always marked
11318 external when it is declared in-class, even if an
11319 initializer is present. We mimic the non-template
11320 processing here. */
11326 }
11336 /* Preserve a typedef that names a type. */
11338 {
11341 }
11344 }
11349 }
11350 #undef RETURN
11352 out:
11353 /* Restore the file and line information. */
11357 }
11359 /* Substitute into the ARG_TYPES of a function type.
11360 If END is a TREE_CHAIN, leave it and any following types
11361 un-substituted. */
11363 static tree
11365 tree args,
11366 tree end,
11367 tsubst_flags_t complain,
11368 tree in_decl)
11369 {
11370 tree remaining_arg_types;
11374 tree default_arg;
11385 {
11386 /* For a pack expansion, perform substitution on the
11387 entire expression. Later on, we'll handle the arguments
11388 one-by-one. */
11393 /* So that we'll spin through the parameters, one by one. */
11395 else
11396 {
11397 /* We only partially substituted into the parameter
11398 pack. Our type is TYPE_PACK_EXPANSION. */
11401 }
11402 }
11415 {
11417 {
11421 }
11423 }
11424 /* DR 657. */
11428 /* Do array-to-pointer, function-to-pointer conversion, and ignore
11429 top-level qualifiers as required. */
11432 /* We do not substitute into default arguments here. The standard
11433 mandates that they be instantiated only when needed, which is
11434 done in build_over_call. */
11438 {
11439 /* We've instantiated a template before its default arguments
11440 have been parsed. This can happen for a nested template
11441 class, and is not an error unless we require the default
11442 argument in a call of this function. */
11443 remaining_arg_types =
11446 }
11447 else
11448 remaining_arg_types =
11450 }
11453 }
11455 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
11456 *not* handle the exception-specification for FNTYPE, because the
11457 initial substitution of explicitly provided template parameters
11458 during argument deduction forbids substitution into the
11459 exception-specification:
11461 [temp.deduct]
11463 All references in the function type of the function template to the
11464 corresponding template parameters are replaced by the specified tem-
11465 plate argument values. If a substitution in a template parameter or
11466 in the function type of the function template results in an invalid
11467 type, type deduction fails. [Note: The equivalent substitution in
11468 exception specifications is done only when the function is instanti-
11469 ated, at which point a program is ill-formed if the substitution
11470 results in an invalid type.] */
11472 static tree
11474 tree args,
11475 tsubst_flags_t complain,
11476 tree in_decl)
11477 {
11478 tree return_type;
11480 tree fntype;
11482 /* The TYPE_CONTEXT is not used for function/method types. */
11485 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
11486 failure. */
11490 {
11491 /* Substitute the argument types. */
11503 {
11504 /* DR 1207: 'this' is in scope in the trailing return type. */
11506 }
11508 /* Substitute the return type. */
11512 {
11515 }
11516 }
11517 else
11518 /* Substitute the return type. */
11523 /* DR 486 clarifies that creation of a function type with an
11524 invalid return type is a deduction failure. */
11527 {
11529 {
11532 else
11534 }
11536 }
11537 /* And DR 657. */
11542 {
11543 /* Substitute the argument types. */
11548 }
11550 /* Construct a new type node and return it. */
11552 {
11557 }
11558 else
11559 {
11561 /* Don't pick up extra function qualifiers from the basetype. */
11564 {
11565 /* [temp.deduct]
11567 Type deduction may fail for any of the following
11568 reasons:
11570 -- Attempting to create "pointer to member of T" when T
11571 is not a class type. */
11574 r);
11576 }
11581 }
11588 }
11590 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
11591 ARGS into that specification, and return the substituted
11592 specification. If there is no specification, return NULL_TREE. */
11594 static tree
11596 tree args,
11597 tsubst_flags_t complain,
11598 tree in_decl,
11600 {
11601 tree specs;
11602 tree new_specs;
11607 {
11608 /* A noexcept-specifier. */
11613 {
11614 /* Defer instantiation of noexcept-specifiers to avoid
11615 excessive instantiations (c++/49107). */
11618 {
11619 /* We already partially instantiated this member template,
11620 so combine the new args with the old. */
11625 }
11626 else
11627 {
11630 }
11631 }
11632 else
11633 new_specs = tsubst_copy_and_build
11637 }
11639 {
11642 else
11644 {
11645 tree spec;
11650 {
11651 /* Expand the pack expansion type. */
11654 in_decl);
11660 else
11661 {
11662 /* We're substituting into a member template, so
11663 we got a TYPE_PACK_EXPANSION back. Add that
11664 expansion and move on. */
11668 expanded_specs,
11669 complain);
11672 }
11673 }
11676 {
11679 else
11684 complain);
11685 }
11688 }
11689 }
11691 }
11693 /* Take the tree structure T and replace template parameters used
11694 therein with the argument vector ARGS. IN_DECL is an associated
11695 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
11696 Issue error and warning messages under control of COMPLAIN. Note
11697 that we must be relatively non-tolerant of extensions here, in
11698 order to preserve conformance; if we allow substitutions that
11699 should not be allowed, we may allow argument deductions that should
11700 not succeed, and therefore report ambiguous overload situations
11701 where there are none. In theory, we could allow the substitution,
11702 but indicate that it should have failed, and allow our caller to
11703 make sure that the right thing happens, but we don't try to do this
11704 yet.
11706 This function is used for dealing with types, decls and the like;
11707 for expressions, use tsubst_expr or tsubst_copy. */
11709 tree
11711 {
11734 else
11739 /* Reuse typedefs. We need to do this to handle dependent attributes,
11740 such as attribute aligned. */
11743 {
11747 {
11748 /* DECL represents an alias template and we want to
11749 instantiate it. */
11753 }
11757 {
11761 }
11766 else
11767 /* The typedef is from a non-template context. */
11771 {
11773 r = cp_build_qualified_type_real
11777 }
11778 else
11779 {
11780 /* We don't have an instantiation yet, so drop the typedef. */
11785 }
11786 }
11799 {
11825 {
11831 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
11832 needed. */
11838 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
11839 with TREE_SIDE_EFFECTS that indicates this is not an integral
11840 constant expression. */
11843 {
11846 }
11849 }
11855 {
11868 {
11872 {
11873 /* See through ARGUMENT_PACK_SELECT arguments. */
11875 /* If the selected argument is an expansion E, that most
11876 likely means we were called from
11877 gen_elem_of_pack_expansion_instantiation during the
11878 substituting of pack an argument pack (which Ith
11879 element is a pack expansion, where I is
11880 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
11881 In this case, the Ith element resulting from this
11882 substituting is going to be a pack expansion, which
11883 pattern is the pattern of E. Let's return the
11884 pattern of E, and
11885 gen_elem_of_pack_expansion_instantiation will
11886 build the resulting pack expansion from it. */
11888 {
11889 /* Make sure we aren't throwing away arg info. */
11892 }
11893 }
11894 }
11899 {
11901 /* If ARG is an argument pack, we don't actually want to
11902 perform a substitution here, because substitutions
11903 for argument packs are only done
11904 element-by-element. We can get to this point when
11905 substituting the type of a non-type template
11906 parameter pack, when that type actually contains
11907 template parameter packs from an outer template, e.g.,
11909 template<typename... Types> struct A {
11910 template<Types... Values> struct B { };
11911 }; */
11915 {
11921 return cp_build_qualified_type_real
11923 }
11925 {
11926 /* We are processing a type constructed from a
11927 template template parameter. */
11938 /* Consider this code:
11940 template <template <class> class Template>
11941 struct Internal {
11942 template <class Arg> using Bind = Template<Arg>;
11943 };
11945 template <template <class> class Template, class Arg>
11946 using Instantiate = Template<Arg>; //#0
11948 template <template <class> class Template,
11949 class Argument>
11950 using Bind =
11951 Instantiate<Internal<Template>::template Bind,
11952 Argument>; //#1
11954 When #1 is parsed, the
11955 BOUND_TEMPLATE_TEMPLATE_PARM representing the
11956 parameter `Template' in #0 matches the
11957 UNBOUND_CLASS_TEMPLATE representing the argument
11958 `Internal<Template>::template Bind'; We then want
11959 to assemble the type `Bind<Argument>' that can't
11960 be fully created right now, because
11961 `Internal<Template>' not being complete, the Bind
11962 template cannot be looked up in that context. So
11963 we need to "store" `Bind<Argument>' for later
11964 when the context of Bind becomes complete. Let's
11965 store that in a TYPENAME_TYPE. */
11969 argvec),
11970 typename_type,
11971 complain);
11973 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
11974 are resolving nested-types in the signature of a
11975 member function templates. Otherwise ARG is a
11976 TEMPLATE_DECL and is the real template to be
11977 instantiated. */
11985 complain);
11986 return cp_build_qualified_type_real
11988 }
11989 else
11990 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
11992 }
11995 /* This can happen during the attempted tsubst'ing in
11996 unify. This means that we don't yet have any information
11997 about the template parameter in question. */
12000 /* Early in template argument deduction substitution, we don't
12001 want to reduce the level of 'auto', or it will be confused
12002 with a normal template parm in subsequent deduction. */
12006 /* If we get here, we must have been looking at a parm for a
12007 more deeply nested template. Make a new version of this
12008 template parameter, but with a lower level. */
12010 {
12015 {
12017 r = cp_build_qualified_type_real
12021 }
12022 else
12023 {
12034 /* We have reduced the level of the template
12035 template parameter, but not the levels of its
12036 template parameters, so canonical_type_parameter
12037 will not be able to find the canonical template
12038 template parameter for this level. Thus, we
12039 require structural equality checking to compare
12040 TEMPLATE_TEMPLATE_PARMs. */
12044 else
12048 {
12056 }
12057 }
12066 }
12069 }
12072 {
12080 {
12084 }
12087 {
12091 }
12094 {
12098 }
12104 }
12107 /* We should never be tsubsting a binfo. */
12111 /* A vector of template arguments. */
12117 {
12121 /* [temp.deduct]
12123 Type deduction may fail for any of the following
12124 reasons:
12126 -- Attempting to create a pointer to reference type.
12127 -- Attempting to create a reference to a reference type or
12128 a reference to void.
12130 Core issue 106 says that creating a reference to a reference
12131 during instantiation is no longer a cause for failure. We
12132 only enforce this check in strict C++98 mode. */
12136 {
12139 /* We keep track of the last time we issued this error
12140 message to avoid spewing a ton of messages during a
12141 single bad template instantiation. */
12144 {
12149 else
12152 }
12155 }
12159 {
12161 {
12164 type);
12165 else
12167 type);
12168 }
12170 }
12172 {
12176 }
12178 /* In C++0x, during template argument substitution, when there is an
12179 attempt to create a reference to a reference type, reference
12180 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
12182 "If a template-argument for a template-parameter T names a type
12183 that is a reference to a type A, an attempt to create the type
12184 'lvalue reference to cv T' creates the type 'lvalue reference to
12185 A,' while an attempt to create the type type rvalue reference to
12186 cv T' creates the type T"
12187 */
12188 r = cp_build_reference_type
12191 else
12199 {
12201 pedwarn
12203 code == REFERENCE_TYPE
12206 else
12208 }
12211 /* Will this ever be needed for TYPE_..._TO values? */
12215 }
12217 {
12220 {
12221 /* [temp.deduct]
12223 Type deduction may fail for any of the following
12224 reasons:
12226 -- Attempting to create "pointer to member of T" when T
12227 is not a class type. */
12231 }
12233 {
12237 }
12239 {
12243 }
12246 {
12247 /* The type of the implicit object parameter gets its
12248 cv-qualifiers from the FUNCTION_TYPE. */
12249 tree memptr;
12250 tree method_type
12255 complain);
12256 }
12257 else
12260 complain);
12261 }
12264 {
12265 tree fntype;
12266 tree specs;
12271 /* Substitute the exception specification. */
12279 }
12281 {
12286 /* As an optimization, we avoid regenerating the array type if
12287 it will obviously be the same as T. */
12291 /* These checks should match the ones in create_array_type_for_decl.
12293 [temp.deduct]
12295 The deduction may fail for any of the following reasons:
12297 -- Attempting to create an array with an element type that
12298 is void, a function type, or a reference type, or [DR337]
12299 an abstract class type. */
12305 {
12309 }
12317 {
12320 }
12323 }
12326 {
12336 {
12340 }
12342 {
12343 /* Normally, make_typename_type does not require that the CTX
12344 have complete type in order to allow things like:
12346 template <class T> struct S { typename S<T>::X Y; };
12348 But, such constructs have already been resolved by this
12349 point, so here CTX really should have complete type, unless
12350 it's a partial instantiation. */
12353 {
12357 }
12358 }
12365 {
12368 }
12371 {
12373 {
12377 else
12379 }
12381 {
12385 else
12387 }
12388 }
12390 return cp_build_qualified_type_real
12392 }
12395 {
12407 }
12410 {
12411 tree type;
12427 complain);
12428 }
12431 {
12432 tree type;
12450 else
12451 {
12455 /* In a template ~id could be either a complement expression
12456 or an unqualified-id naming a destructor; if instantiating
12457 it produces an expression, it's not an id-expression or
12458 member access. */
12461 }
12466 }
12469 {
12473 }
12477 {
12479 tree packed_out =
12481 args,
12482 complain,
12483 in_decl);
12486 /* For template nontype argument packs, also substitute into
12487 the type. */
12492 }
12508 /* We should use one of the expression tsubsts for these codes. */
12514 }
12515 }
12517 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
12518 type of the expression on the left-hand side of the "." or "->"
12519 operator. */
12521 static tree
12524 {
12525 tree name;
12526 tree qualifying_scope;
12527 tree fns;
12528 tree optype;
12533 /* A baselink indicates a function from a base class. Both the
12534 BASELINK_ACCESS_BINFO and the base class referenced may
12535 indicate bases of the template class, rather than the
12536 instantiated class. In addition, lookups that were not
12537 ambiguous before may be ambiguous now. Therefore, we perform
12538 the lookup again. */
12545 {
12552 }
12560 /* If lookup found a single function, mark it as used at this
12561 point. (If it lookup found multiple functions the one selected
12562 later by overload resolution will be marked as used at that
12563 point.) */
12569 /* Add back the template arguments, if present. */
12574 template_args);
12575 /* Update the conversion operator type. */
12583 qualifying_scope,
12584 object_type);
12586 }
12588 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
12589 true if the qualified-id will be a postfix-expression in-and-of
12590 itself; false if more of the postfix-expression follows the
12591 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
12592 of "&". */
12594 static tree
12598 {
12599 tree expr;
12600 tree scope;
12601 tree name;
12603 tree template_args;
12608 /* Figure out what name to look up. */
12611 {
12619 }
12620 else
12621 {
12624 }
12626 /* Substitute into the qualifying scope. When there are no ARGS, we
12627 are just trying to simplify a non-dependent expression. In that
12628 case the qualifying scope may be dependent, and, in any case,
12629 substituting will not help. */
12632 {
12635 }
12636 else
12640 {
12645 }
12648 {
12650 {
12651 /* A BIT_NOT_EXPR is used to represent a destructor. */
12653 {
12657 }
12658 else
12661 }
12662 else
12666 {
12668 {
12672 }
12674 }
12675 }
12678 {
12680 scope);
12681 /* Remember that there was a reference to this entity. */
12683 }
12686 {
12692 }
12701 {
12702 expr = (adjust_result_of_qualified_name_lookup
12704 expr = (finish_qualified_id_expr
12708 }
12710 /* Expressions do not generally have reference type. */
12712 /* However, if we're about to form a pointer-to-member, we just
12713 want the referenced member referenced. */
12718 }
12720 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
12721 initializer, DECL is the substituted VAR_DECL. Other arguments are as
12722 for tsubst. */
12724 static tree
12727 {
12734 {
12735 /* If we had an initializer but it
12736 instantiated to nothing,
12737 value-initialize the object. This will
12738 only occur when the initializer was a
12739 pack expansion where the parameter packs
12740 used in that expansion were of length
12741 zero. */
12743 complain);
12746 }
12749 }
12751 /* Like tsubst, but deals with expressions. This function just replaces
12752 template parms; to finish processing the resultant expression, use
12753 tsubst_copy_and_build or tsubst_expr. */
12755 static tree
12757 {
12759 tree r;
12767 {
12772 {
12773 /* We get here for a use of 'this' in an NSDMI. */
12775 && current_function_decl
12779 /* This can happen for a parameter name used later in a function
12780 declaration (such as in a late-specified return type). Just
12781 make a dummy decl, since it's only used for its type. */
12784 /* Give it the template pattern as its context; its true context
12785 hasn't been instantiated yet and this is good enough for
12786 mangling. */
12788 }
12796 {
12797 tree enum_type;
12798 tree v;
12802 /* There is no need to substitute into namespace-scope
12803 enumerators. */
12806 /* If ARGS is NULL, then T is known to be non-dependent. */
12810 /* Unfortunately, we cannot just call lookup_name here.
12811 Consider:
12813 template <int I> int f() {
12814 enum E { a = I };
12815 struct S { void g() { E e = a; } };
12816 };
12818 When we instantiate f<7>::S::g(), say, lookup_name is not
12819 clever enough to find f<7>::a. */
12820 enum_type
12830 /* We didn't find the name. That should never happen; if
12831 name-lookup found it during preliminary parsing, we
12832 should find it again here during instantiation. */
12834 }
12839 {
12840 /* Check for a local specialization set up by
12841 tsubst_pack_expansion. */
12843 {
12847 }
12849 /* When retrieving a capture pack from a generic lambda, remove the
12850 lambda call op's own template argument list from ARGS. Only the
12851 template arguments active for the closure type should be used to
12852 retrieve the pack specialization. */
12858 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
12859 tsubst_decl put in the hash table. */
12861 }
12864 {
12865 tree ctx;
12870 {
12873 {
12877 }
12879 }
12880 }
12889 {
12892 {
12893 /* First try name lookup to find the instantiation. */
12896 {
12897 /* Make sure that the one we found is the one we want. */
12902 }
12906 else
12907 {
12908 /* This can happen for a variable used in a
12909 late-specified return type of a local lambda, or for a
12910 local static or constant. Building a new VAR_DECL
12911 should be OK in all those cases. */
12914 {
12915 /* We can't call cp_finish_decl, so handle the
12916 initializer by hand. */
12927 }
12932 {
12935 at_eof);
12937 /* A use of a local constant decays to its value.
12938 FIXME update for core DR 696. */
12940 }
12941 }
12942 /* Remember this for subsequent uses. */
12945 }
12946 }
12947 else
12956 /* An OVERLOAD will always be a non-dependent overload set; an
12957 overload set from function scope will just be represented with an
12958 IDENTIFIER_NODE, and from class scope with a BASELINK. */
12974 {
12975 /* Template template argument like the following example need
12976 special treatment:
12978 template <template <class> class TT> struct C {};
12979 template <class T> struct D {
12980 template <class U> struct E {};
12981 C<E> c; // #1
12982 };
12983 D<int> d; // #2
12985 We are processing the template argument `E' in #1 for
12986 the template instantiation #2. Originally, `E' is a
12987 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
12988 have to substitute this with one having context `D<int>'. */
12992 }
12993 else
12994 /* Ordinary template template argument. */
13005 {
13009 }
13013 {
13023 /* We only want to compute the number of arguments. */
13037 {
13044 else
13047 }
13048 else
13050 }
13052 {
13060 }
13061 /* Fall through */
13077 {
13081 }
13084 {
13085 tree object;
13086 tree name;
13091 {
13095 }
13098 {
13108 }
13113 in_decl);
13114 else
13117 }
13155 {
13159 }
13162 {
13167 }
13170 {
13174 }
13177 {
13185 }
13191 {
13198 }
13201 {
13208 }
13211 {
13218 }
13221 {
13222 /* Substituted template arguments */
13231 }
13234 {
13254 }
13279 /* Fall through. */
13282 {
13285 }
13286 else
13290 /* This is handled by tsubst_copy_and_build. */
13294 {
13298 }
13301 /* We shouldn't have built any of these during initial template
13302 generation. Instead, they should be built during instantiation
13303 in response to the saved STMT_IS_FULL_EXPR_P setting. */
13307 {
13315 }
13333 {
13334 /* Instantiate any typedefs in the type. */
13339 }
13342 /* These can sometimes show up in a partial instantiation, but never
13343 involve template parms. */
13348 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
13351 }
13352 }
13354 /* Like tsubst_copy, but specifically for OpenMP clauses. */
13356 static tree
13359 {
13363 {
13369 {
13372 {
13378 }
13379 /* FALLTHRU */
13407 {
13410 {
13417 }
13418 else
13420 }
13450 }
13451 }
13457 }
13459 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
13461 static tree
13463 tree in_decl)
13464 {
13465 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
13485 {
13488 else
13489 {
13493 }
13494 }
13499 #undef RECUR
13500 }
13502 /* Substitute one OMP_FOR iterator. */
13504 static void
13509 {
13510 #define RECUR(NODE) \
13511 tsubst_expr ((NODE), args, complain, in_decl, \
13512 integral_constant_expression_p)
13521 {
13522 /* We need to jump through some hoops to handle declarations in the
13523 for-init-statement, since we might need to handle auto deduction,
13524 but we need to keep control of initialization. */
13528 }
13529 else
13541 {
13543 {
13544 /* Declare the variable, but don't let that initialize it. */
13549 }
13554 {
13559 }
13560 else
13567 }
13570 {
13571 /* Declare and initialize the variable. */
13574 }
13576 {
13577 tree c;
13579 {
13590 }
13592 {
13597 {
13600 }
13601 }
13602 }
13605 {
13609 }
13610 else
13614 {
13625 {
13633 }
13634 else
13640 {
13646 }
13650 {
13658 }
13659 else
13665 }
13671 #undef RECUR
13672 }
13674 /* Like tsubst_copy for expressions, etc. but also does semantic
13675 processing. */
13677 static tree
13680 {
13681 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
13682 #define RECUR(NODE) \
13683 tsubst_expr ((NODE), args, complain, in_decl, \
13684 integral_constant_expression_p)
13687 tree r;
13688 location_t loc;
13700 {
13702 {
13703 tree_stmt_iterator i;
13707 }
13722 else
13731 {
13733 tree init;
13739 {
13742 tree decl;
13750 else
13752 }
13754 {
13755 /* Don't build up decls for a variadic capture proxy, we'll
13756 instantiate the elements directly as needed. */
13758 }
13759 else
13760 {
13764 {
13765 /* By marking the declaration as instantiated, we avoid
13766 trying to instantiate it. Since instantiate_decl can't
13767 handle local variables, and since we've already done
13768 all that needs to be done, that's the right thing to
13769 do. */
13774 /* Anonymous aggregates are a special case. */
13777 {
13780 {
13784 }
13786 }
13792 {
13797 }
13798 else
13799 {
13804 {
13805 /* For __PRETTY_FUNCTION__ we have to adjust the
13806 initializer. */
13810 }
13811 else
13815 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
13818 }
13819 }
13820 }
13823 }
13838 {
13848 }
13875 {
13879 }
13887 else
13895 else
13916 {
13920 }
13924 {
13926 tree label;
13931 }
13937 /* Computed goto's must be tsubst'd into. On the other hand,
13938 non-computed gotos must not be; the identifier in question
13939 will have no binding. */
13941 else
13947 {
13963 }
13968 {
13973 }
13974 else
13975 {
13980 else
13987 else
13993 else
13995 }
13999 {
14003 {
14005 /* Prevent instantiate_decl from trying to instantiate
14006 this variable. We've already done all that needs to be
14007 done. */
14010 }
14015 }
14021 {
14022 /* Local classes are not independent templates; they are
14023 instantiated along with their containing function. And this
14024 way we don't have to deal with pushing out of one local class
14025 to instantiate a member of another local class. */
14026 tree fn;
14027 /* Closures are handled by the LAMBDA_EXPR. */
14033 }
14037 {
14038 tree condition;
14041 condition =
14043 args,
14052 }
14077 {
14086 {
14091 }
14103 integral_constant_expression_p);
14112 else
14113 {
14121 }
14124 }
14183 {
14188 {
14191 }
14197 }
14198 else
14199 {
14206 {
14209 }
14212 {
14217 {
14220 }
14226 }
14227 else
14228 {
14232 }
14235 }
14239 {
14245 {
14249 {
14254 }
14258 }
14259 else
14260 {
14265 }
14266 }
14270 {
14274 }
14294 /* If the first operand was a statement, we're done with it. */
14298 complain));
14310 integral_constant_expression_p));
14311 }
14314 out:
14317 #undef RECUR
14318 #undef RETURN
14319 }
14321 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
14322 function. For description of the body see comment above
14323 cp_parser_omp_declare_reduction_exprs. */
14325 static void
14327 {
14333 tree_stmt_iterator tsi;
14344 {
14363 }
14365 {
14385 }
14386 }
14388 /* T is a postfix-expression that is not being used in a function
14389 call. Return the substituted version of T. */
14391 static tree
14393 tsubst_flags_t complain,
14394 tree in_decl)
14395 {
14399 else
14405 }
14407 /* Sentinel to disable certain warnings during template substitution. */
14415 };
14417 /* Like tsubst but deals with expressions and performs semantic
14418 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
14420 tree
14422 tree args,
14423 tsubst_flags_t complain,
14424 tree in_decl,
14427 {
14428 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
14429 #define RECUR(NODE) \
14430 tsubst_copy_and_build (NODE, args, complain, in_decl, \
14432 integral_constant_expression_p)
14435 location_t loc;
14444 /* N3276 decltype magic only applies to calls at the top level or on the
14445 right side of a comma. */
14450 {
14453 /* Fall through. */
14455 {
14456 tree decl;
14457 cp_id_kind idk;
14462 {
14465 }
14467 /* Look up the name. */
14470 /* By convention, expressions use ERROR_MARK_NODE to indicate
14471 failure, not NULL_TREE. */
14477 integral_constant_expression_p,
14485 input_location);
14489 {
14493 }
14495 }
14498 {
14499 tree object;
14507 {
14510 }
14511 else
14518 else
14520 }
14523 {
14527 {
14528 /* A type conversion to reference type will be enclosed in
14529 such an indirect ref, but the substitution of the cast
14530 will have also added such an indirect ref. */
14533 }
14534 else
14538 }
14541 {
14545 }
14548 {
14555 flags));
14556 }
14559 {
14563 }
14570 {
14571 tree type;
14577 {
14582 }
14588 {
14606 }
14609 }
14643 else
14645 in_decl);
14680 {
14685 tree r = build_x_binary_op
14687 op0,
14689 ? ERROR_MARK
14691 op1,
14693 ? ERROR_MARK
14701 }
14704 {
14708 }
14721 {
14730 }
14734 /* Fall through */
14737 {
14738 tree r;
14744 {
14745 /* When there are no ARGS, we are trying to evaluate a
14746 non-dependent expression from the parser. Trying to do
14747 the substitutions may not work. */
14750 }
14751 else
14752 {
14757 else
14760 /*integral_constant_expression_p=*/
14764 }
14768 else
14772 {
14774 {
14776 {
14780 }
14781 else
14785 }
14787 }
14789 }
14792 {
14802 }
14818 {
14822 tree r = build_x_modify_expr
14825 /* TREE_NO_WARNING must be set if either the expression was
14826 parenthesized or it uses an operator such as >>= rather
14827 than plain assignment. In the former case, it was already
14828 set and must be copied. In the latter case,
14829 build_x_modify_expr sets it and it must not be reset
14830 here. */
14835 }
14840 /* Remember that there was a reference to this entity. */
14846 {
14851 tree ret;
14855 else
14856 {
14860 }
14862 /* If there was an initializer in the original tree, but it
14863 instantiated to an empty list, then we should pass a
14864 non-NULL empty vector to tell build_new that it was an
14865 empty initializer() rather than no initializer. This can
14866 only happen when the initializer is a pack expansion whose
14867 parameter packs are of length zero. */
14870 else
14871 {
14875 else
14876 {
14879 }
14880 }
14886 complain);
14894 }
14897 {
14903 complain));
14904 }
14907 {
14911 integral_constant_expression_p);
14913 op0,
14916 }
14919 {
14920 tree function;
14925 tree ret;
14928 /* When we parsed the expression, we determined whether or
14929 not Koenig lookup should be performed. */
14932 {
14937 }
14939 {
14940 /* Do nothing; calling tsubst_copy_and_build on an identifier
14941 would incorrectly perform unqualified lookup again.
14943 Note that we can also have an IDENTIFIER_NODE if the earlier
14944 unqualified lookup found a member function; in that case
14945 koenig_p will be false and we do want to do the lookup
14946 again to find the instantiated member function.
14948 FIXME but doing that causes c++/15272, so we need to stop
14949 using IDENTIFIER_NODE in that situation. */
14951 }
14952 else
14953 {
14955 {
14961 }
14962 else
14967 /* Avoid error about taking the address of a constructor. */
14971 in_decl,
14973 integral_constant_expression_p);
14977 }
14982 {
14987 else
14988 {
14989 /* Expand the pack expansion and push each entry onto
14990 CALL_ARGS. */
14993 {
14998 {
15003 }
15004 }
15005 else
15006 {
15007 /* A partial substitution. Add one entry. */
15009 }
15010 }
15011 }
15013 /* We do not perform argument-dependent lookup if normal
15014 lookup finds a non-function, in accordance with the
15015 expected resolution of DR 218. */
15018 /* If lookup found a member function, the Koenig lookup is
15019 not appropriate, even if an unqualified-name was used
15020 to denote the function. */
15023 /* Only do this when substitution turns a dependent call
15024 into a non-dependent call. */
15031 {
15033 {
15034 /* For backwards compatibility and good diagnostics, try
15035 the unqualified lookup again if we aren't in SFINAE
15036 context. */
15037 tree unq = (tsubst_copy_and_build
15039 integral_constant_expression_p));
15044 {
15053 "%qD was not declared in this scope, "
15054 "and no declarations were found by "
15055 "argument-dependent lookup at the point "
15057 {
15061 {
15063 input_location);
15065 "declarations in dependent base %qT are "
15071 else
15075 }
15076 else
15079 }
15081 }
15082 }
15084 {
15089 }
15090 }
15092 /* Remember that there was a reference to this entity. */
15096 /* Put back tf_decltype for the actual call. */
15101 complain);
15103 {
15118 complain);
15119 else
15120 ret = (build_new_method_call
15125 complain));
15126 }
15127 else
15130 koenig_p,
15131 complain);
15136 }
15139 {
15145 {
15147 {
15152 }
15153 else
15154 {
15159 }
15161 }
15162 else
15163 {
15166 }
15170 }
15173 {
15178 input_location));
15179 }
15182 {
15190 {
15191 /* We have pack expansions, so expand those and
15192 create a new list out of it. */
15195 tree chain;
15198 /* Expand the argument expressions. */
15206 /* Build the rest of the list. */
15211 /* Determine the number of arguments. */
15213 {
15216 }
15219 else
15220 {
15221 /* Since we only performed a partial substitution into
15222 the argument pack, we only RETURN (a single list
15223 node. */
15230 }
15232 /* Convert the argument vectors into a TREE_LIST */
15235 {
15236 /* Grab the Ith values. */
15237 i--;
15240 value
15244 /* Build the list (backwards). */
15246 }
15249 }
15265 }
15268 {
15269 tree object;
15270 tree object_type;
15271 tree member;
15272 tree r;
15276 /* Remember that there was a reference to this entity. */
15286 else
15294 {
15296 {
15301 {
15304 }
15306 {
15311 }
15312 }
15313 }
15316 {
15317 /* Lookup the template functions now that we know what the
15318 scope is. */
15326 {
15329 args);
15330 member = (adjust_result_of_qualified_name_lookup
15332 object_type));
15333 }
15334 else
15335 {
15337 input_location);
15339 }
15340 }
15344 {
15346 {
15350 else
15353 }
15355 }
15357 {
15362 }
15366 complain);
15370 }
15377 {
15385 tree r;
15390 /* digest_init will do the wrong thing if we let it. */
15394 /* We do not want to process the index of aggregate
15395 initializers as they are identifier nodes which will be
15396 looked up by digest_init. */
15402 {
15404 /* An identifier index is looked up in the type
15405 being initialized, not the current scope. */
15410 {
15411 /* Substitute into the pack expansion. */
15413 in_decl);
15417 ;
15419 /* Just move the argument into place. */
15421 else
15422 {
15423 /* Update the length of the final CONSTRUCTOR
15424 arguments vector, and note that we will need to
15425 copy.*/
15428 }
15429 }
15430 else
15432 }
15435 {
15440 {
15442 {
15447 }
15448 else
15450 }
15451 }
15461 }
15464 {
15467 {
15470 }
15471 else
15472 {
15475 }
15476 }
15482 {
15483 /* We don't build decls for an instantiation of a
15484 variadic capture proxy, we instantiate the elements
15485 when needed. */
15488 }
15489 /* Fall through */
15492 {
15494 /* ??? We're doing a subset of finish_id_expression here. */
15496 && !processing_template_decl
15497 && !cp_unevaluated_operand
15500 {
15502 /* Replace an evaluated use of the thread_local variable with
15503 a call to its wrapper. */
15505 }
15510 /* If the original type was a reference, we'll be wrapped in
15511 the appropriate INDIRECT_REF. */
15514 }
15517 {
15521 }
15528 {
15539 }
15542 {
15548 integral_constant_expression_p);
15552 /* If the resulting list of expression statement is empty,
15553 fold it further into void_node. */
15558 }
15561 {
15575 /* For a function scope, we want to use tsubst so that we don't
15576 complain about referring to an auto function before its return
15577 type has been deduced. Otherwise, we want to use tsubst_copy so
15578 that we look up the existing field/parameter/variable rather
15579 than build a new one. */
15584 {
15585 /* Look up the parameter we want directly, as tsubst_copy
15586 doesn't do what we need. */
15592 /* FIXME Work around the parm not having DECL_CONTEXT set. */
15595 }
15596 else
15605 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
15607 /* Now that we know visibility, instantiate the type so we have a
15608 declaration of the op() for later calls to lambda_function. */
15614 }
15617 /* We can get here for a constant initializer of non-dependent type.
15618 FIXME stop folding in cp_parser_initializer_clause. */
15619 {
15621 complain);
15623 }
15627 integral_constant_expression_p));
15633 {
15638 complain));
15639 }
15642 /* Handle Objective-C++ constructs, if appropriate. */
15643 {
15644 tree subst
15649 }
15651 }
15653 #undef RECUR
15654 #undef RETURN
15655 out:
15658 }
15660 /* Verify that the instantiated ARGS are valid. For type arguments,
15661 make sure that the type's linkage is ok. For non-type arguments,
15662 make sure they are constants if they are integral or enumerations.
15663 Emit an error under control of COMPLAIN, and return TRUE on error. */
15665 static bool
15667 {
15671 {
15681 }
15683 {
15684 /* [basic.link]: A name with no linkage (notably, the name
15685 of a class or enumeration declared in a local scope)
15686 shall not be used to declare an entity with linkage.
15687 This implies that names with no linkage cannot be used as
15688 template arguments
15690 DR 757 relaxes this restriction for C++0x. */
15695 {
15696 /* DR 488 makes use of a type with no linkage cause
15697 type deduction to fail. */
15699 {
15702 else
15705 }
15707 }
15708 /* In order to avoid all sorts of complications, we do not
15709 allow variably-modified types as template arguments. */
15711 {
15715 }
15716 }
15717 /* Class template and alias template arguments should be OK. */
15719 ;
15720 /* A non-type argument of integral or enumerated type must be a
15721 constant. */
15725 {
15729 }
15731 }
15733 static bool
15735 {
15740 {
15743 }
15747 }
15749 /* We're out of SFINAE context now, so generate diagnostics for the access
15750 errors we saw earlier when instantiating D from TMPL and ARGS. */
15752 static void
15754 {
15766 }
15768 /* Instantiate the indicated variable, function, or alias template TMPL with
15769 the template arguments in TARG_PTR. */
15771 static tree
15773 {
15775 tree fndecl;
15776 tree gen_tmpl;
15777 tree spec;
15785 /* If this function is a clone, handle it specially. */
15787 {
15788 tree spec;
15789 tree clone;
15791 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
15792 DECL_CLONED_FUNCTION. */
15798 /* Look for the clone. */
15802 /* We should always have found the clone by now. */
15805 }
15810 /* Check to see if we already have this specialization. */
15813 /* The TMPL is a partial instantiation. To get a full set of
15814 arguments we must add the arguments used to perform the
15815 partial instantiation. */
15817 targ_ptr);
15819 /* It would be nice to avoid hashing here and then again in tsubst_decl,
15820 but it doesn't seem to be on the hot path. */
15829 {
15831 {
15835 }
15837 }
15840 complain))
15843 /* We are building a FUNCTION_DECL, during which the access of its
15844 parameters and return types have to be checked. However this
15845 FUNCTION_DECL which is the desired context for access checking
15846 is not built yet. We solve this chicken-and-egg problem by
15847 deferring all checks until we have the FUNCTION_DECL. */
15850 /* Instantiation of the function happens in the context of the function
15851 template, not the context of the overload resolution we're doing. */
15853 /* If there are dependent arguments, e.g. because we're doing partial
15854 ordering, make sure processing_template_decl stays set. */
15858 {
15862 }
15863 /* Substitute template parameters to obtain the specialization. */
15871 {
15874 }
15876 /* The DECL_TI_TEMPLATE should always be the immediate parent
15877 template, not the most general template. */
15880 /* Now we know the specialization, compute access previously
15881 deferred. */
15888 /* If we've just instantiated the main entry point for a function,
15889 instantiate all the alternate entry points as well. We do this
15890 by cloning the instantiation of the main entry point, not by
15891 instantiating the template clones. */
15896 {
15898 {
15899 /* Remember to reinstantiate when we're out of SFINAE so the user
15900 can see the errors. */
15902 }
15904 }
15906 }
15908 /* Wrapper for instantiate_template_1. */
15910 tree
15912 {
15913 tree ret;
15918 }
15920 /* Instantiate the alias template TMPL with ARGS. Also push a template
15921 instantiation level, which instantiate_template doesn't do because
15922 functions and variables have sufficient context established by the
15923 callers. */
15925 static tree
15927 {
15934 {
15937 }
15939 args =
15947 /* We can't free this if a pending_template entry or last_error_tinst_level
15948 is pointing at it. */
15954 }
15956 /* PARM is a template parameter pack for FN. Returns true iff
15957 PARM is used in a deducible way in the argument list of FN. */
15959 static bool
15961 {
15964 {
15966 tree packs;
15972 {
15973 /* The template parameter pack is used in a function parameter
15974 pack. If this is the end of the parameter list, the
15975 template parameter pack is deducible. */
15978 else
15979 /* Otherwise, not. Well, it could be deduced from
15980 a non-pack parameter, but doing so would end up with
15981 a deduction mismatch, so don't bother. */
15983 }
15984 }
15985 /* The template parameter pack isn't used in any function parameter
15986 packs, but it might be used deeper, e.g. tuple<Args...>. */
15988 }
15990 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
15991 NARGS elements of the arguments that are being used when calling
15992 it. TARGS is a vector into which the deduced template arguments
15993 are placed.
15995 Returns either a FUNCTION_DECL for the matching specialization of FN or
15996 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
15997 true, diagnostics will be printed to explain why it failed.
15999 If FN is a conversion operator, or we are trying to produce a specific
16000 specialization, RETURN_TYPE is the return type desired.
16002 The EXPLICIT_TARGS are explicit template arguments provided via a
16003 template-id.
16005 The parameter STRICT is one of:
16007 DEDUCE_CALL:
16008 We are deducing arguments for a function call, as in
16009 [temp.deduct.call].
16011 DEDUCE_CONV:
16012 We are deducing arguments for a conversion function, as in
16013 [temp.deduct.conv].
16015 DEDUCE_EXACT:
16016 We are deducing arguments when doing an explicit instantiation
16017 as in [temp.explicit], when determining an explicit specialization
16018 as in [temp.expl.spec], or when taking the address of a function
16019 template, as in [temp.deduct.funcaddr]. */
16021 tree
16023 tree explicit_targs,
16024 tree targs,
16027 tree return_type,
16028 unification_kind_t strict,
16032 {
16033 tree parms;
16034 tree fntype;
16042 tree tinst;
16048 /* In C++0x, it's possible to have a function template whose type depends
16049 on itself recursively. This is most obvious with decltype, but can also
16050 occur with enumeration scope (c++/48969). So we need to catch infinite
16051 recursion and reject the substitution at deduction time; this function
16052 will return error_mark_node for any repeated substitution.
16054 This also catches excessive recursion such as when f<N> depends on
16055 f<N-1> across all integers, and returns error_mark_node for all the
16056 substitutions back up to the initial one.
16058 This is, of course, not reentrant. */
16068 {
16069 /* [temp.deduct]
16071 The specified template arguments must match the template
16072 parameters in kind (i.e., type, nontype, template), and there
16073 must not be more arguments than there are parameters;
16074 otherwise type deduction fails.
16076 Nontype arguments must match the types of the corresponding
16077 nontype template parameters, or must be convertible to the
16078 types of the corresponding nontype parameters as specified in
16079 _temp.arg.nontype_, otherwise type deduction fails.
16081 All references in the function type of the function template
16082 to the corresponding template parameters are replaced by the
16083 specified template argument values. If a substitution in a
16084 template parameter or in the function type of the function
16085 template results in an invalid type, type deduction fails. */
16090 /* Adjust any explicit template arguments before entering the
16091 substitution context. */
16092 explicit_targs
16094 complain,
16100 /* Substitute the explicit args into the function type. This is
16101 necessary so that, for instance, explicitly declared function
16102 arguments can match null pointed constants. If we were given
16103 an incomplete set of explicit args, we must not do semantic
16104 processing during substitution as we could create partial
16105 instantiations. */
16107 {
16112 /* Dig out the actual parm. */
16115 {
16118 }
16120 {
16123 }
16126 /* No explicit argument for this template parameter. */
16130 {
16131 /* Mark the argument pack as "incomplete". We could
16132 still deduce more arguments during unification.
16133 We remove this mark in type_unification_real. */
16135 {
16139 }
16141 /* We have some incomplete argument packs. */
16143 }
16144 }
16148 {
16151 }
16154 /* Ignore any access checks; we'll see them again in
16155 instantiate_template and they might have the wrong
16156 access path at this point. */
16168 /* Place the explicitly specified arguments in TARGS. */
16171 }
16173 /* Never do unification on the 'this' parameter. */
16177 {
16186 }
16188 /* We allow incomplete unification without an error message here
16189 because the standard doesn't seem to explicitly prohibit it. Our
16190 callers must be ready to deal with unification failures in any
16191 event. */
16194 /* If we aren't explaining yet, push tinst context so we can see where
16195 any errors (e.g. from class instantiations triggered by instantiation
16196 of default template arguments) come from. If we are explaining, this
16197 context is redundant. */
16199 {
16202 }
16204 /* type_unification_real will pass back any access checks from default
16205 template argument substitution. */
16217 /* Now that we have bindings for all of the template arguments,
16218 ensure that the arguments deduced for the template template
16219 parameters have compatible template parameter lists. We cannot
16220 check this property before we have deduced all template
16221 arguments, because the template parameter types of a template
16222 template parameter might depend on prior template parameters
16223 deduced after the template template parameter. The following
16224 ill-formed example illustrates this issue:
16226 template<typename T, template<T> class C> void f(C<5>, T);
16228 template<int N> struct X {};
16230 void g() {
16231 f(X<5>(), 5l); // error: template argument deduction fails
16232 }
16234 The template parameter list of 'C' depends on the template type
16235 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
16236 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
16237 time that we deduce 'C'. */
16240 {
16243 }
16245 /* All is well so far. Now, check:
16247 [temp.deduct]
16249 When all template arguments have been deduced, all uses of
16250 template parameters in nondeduced contexts are replaced with
16251 the corresponding deduced argument values. If the
16252 substitution results in an invalid type, as described above,
16253 type deduction fails. */
16256 {
16259 }
16261 /* Also collect access checks from the instantiation. */
16274 /* Now perform any access checks encountered during substitution. */
16281 /* If we're looking for an exact match, check that what we got
16282 is indeed an exact match. It might not be if some template
16283 parameters are used in non-deduced contexts. But don't check
16284 for an exact match if we have dependent template arguments;
16285 in that case we're doing partial ordering, and we already know
16286 that we have two candidates that will provide the actual type. */
16288 {
16292 tree sarg
16298 {
16302 }
16303 }
16307 fail:
16310 {
16312 /* Reset once we're all the way out. */
16314 }
16316 /* We can't free this if a pending_template entry or last_error_tinst_level
16317 is pointing at it. */
16323 }
16325 /* Adjust types before performing type deduction, as described in
16326 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
16327 sections are symmetric. PARM is the type of a function parameter
16328 or the return type of the conversion function. ARG is the type of
16329 the argument passed to the call, or the type of the value
16330 initialized with the result of the conversion function.
16331 ARG_EXPR is the original argument expression, which may be null. */
16333 static int
16337 tree arg_expr)
16338 {
16342 {
16347 {
16348 /* Swap PARM and ARG throughout the remainder of this
16349 function; the handling is precisely symmetric since PARM
16350 will initialize ARG rather than vice versa. */
16355 }
16358 /* Core issue #873: Do the DR606 thing (see below) for these cases,
16359 too, but here handle it by stripping the reference from PARM
16360 rather than by adding it to ARG. */
16368 /* Nothing else to do in this case. */
16373 }
16376 {
16377 /* [temp.deduct.call]
16379 If P is not a reference type:
16381 --If A is an array type, the pointer type produced by the
16382 array-to-pointer standard conversion (_conv.array_) is
16383 used in place of A for type deduction; otherwise,
16385 --If A is a function type, the pointer type produced by
16386 the function-to-pointer standard conversion
16387 (_conv.func_) is used in place of A for type deduction;
16388 otherwise,
16390 --If A is a cv-qualified type, the top level
16391 cv-qualifiers of A's type are ignored for type
16392 deduction. */
16397 else
16399 }
16401 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
16402 of the form T&&, where T is a template parameter, and the argument
16403 is an lvalue, T is deduced as A& */
16409 /* try_one_overload doesn't provide an arg_expr, but
16410 functions are always lvalues. */
16414 /* [temp.deduct.call]
16416 If P is a cv-qualified type, the top level cv-qualifiers
16417 of P's type are ignored for type deduction. If P is a
16418 reference type, the type referred to by P is used for
16419 type deduction. */
16422 {
16425 }
16427 /* DR 322. For conversion deduction, remove a reference type on parm
16428 too (which has been swapped into ARG). */
16433 }
16435 /* Subroutine of unify_one_argument. PARM is a function parameter of a
16436 template which does contain any deducible template parameters; check if
16437 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
16438 unify_one_argument. */
16440 static int
16443 {
16444 tree type;
16448 else
16455 {
16459 }
16461 {
16466 }
16470 else
16472 }
16476 /* Returns true iff the expression EXPR is one from which a template
16477 argument can be deduced. In other words, if it's an undecorated
16478 use of a template non-type parameter. */
16480 static bool
16482 {
16484 }
16486 /* Returns true iff the array domain DOMAIN uses a template parameter in a
16487 deducible way; that is, if it has a max value of <PARM> - 1. */
16489 static bool
16491 {
16500 }
16502 /* Returns true iff the template arguments ARGS use a template parameter
16503 in a deducible way. */
16505 static bool
16507 {
16509 {
16514 else
16515 {
16522 else
16524 }
16527 }
16529 }
16531 /* Returns true iff TYPE contains any deducible references to template
16532 parameters, as per 14.8.2.5. */
16534 static bool
16536 {
16540 /* T
16541 cv-list T
16542 TT<T>
16543 TT<i>
16544 TT<> */
16549 /* T*
16550 T&
16551 T&& */
16555 /* T[integer-constant ]
16556 type [i] */
16561 /* T type ::*
16562 type T::*
16563 T T::*
16564 T (type ::*)()
16565 type (T::*)()
16566 type (type ::*)(T)
16567 type (T::*)(T)
16568 T (type ::*)(T)
16569 T (T::*)()
16570 T (T::*)(T) */
16573 || (uses_deducible_template_parms
16576 /* template-name <T> (where template-name refers to a class template)
16577 template-name <i> (where template-name refers to a class template) */
16584 /* type (T)
16585 T()
16586 T(T) */
16589 {
16598 }
16601 }
16603 /* Subroutine of type_unification_real and unify_pack_expansion to
16604 handle unification of a single P/A pair. Parameters are as
16605 for those functions. */
16607 static int
16611 {
16618 /* We can't deduce anything from this, but we might get all the
16619 template args from other function args. */
16622 /* Implicit conversions (Clause 4) will be performed on a function
16623 argument to convert it to the type of the corresponding function
16624 parameter if the parameter type contains no template-parameters that
16625 participate in template argument deduction. */
16627 /* For function parameters that contain no template-parameters at all,
16628 we have historically checked for convertibility in order to shortcut
16629 consideration of this candidate. */
16631 explain_p);
16634 /* For function parameters with only non-deducible template parameters,
16635 just return. */
16639 {
16641 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
16642 | UNIFY_ALLOW_MORE_CV_QUAL
16656 }
16658 /* We only do these transformations if this is the top-level
16659 parameter_type_list in a call or declaration matching; in other
16660 situations (nested function declarators, template argument lists) we
16661 won't be comparing a type to an expression, and we don't do any type
16662 adjustments. */
16664 {
16666 {
16669 {
16670 /* [temp.deduct.type] A template-argument can be
16671 deduced from a pointer to function or pointer
16672 to member function argument if the set of
16673 overloaded functions does not contain function
16674 templates and at most one of a set of
16675 overloaded functions provides a unique
16676 match. */
16683 }
16689 }
16691 arg_strict |=
16693 }
16694 else
16699 /* For deduction from an init-list we need the actual list. */
16703 }
16705 /* Most parms like fn_type_unification.
16707 If SUBR is 1, we're being called recursively (to unify the
16708 arguments of a function or method parameter of a function
16709 template).
16711 CHECKS is a pointer to a vector of access checks encountered while
16712 substituting default template arguments. */
16714 static int
16716 tree targs,
16717 tree xparms,
16721 unification_kind_t strict,
16725 {
16730 tree parms;
16739 /* Reset the number of non-defaulted template arguments contained
16740 in TARGS. */
16743 again:
16751 {
16756 /* For a function parameter pack that occurs at the end of the
16757 parameter-declaration-list, the type A of each remaining
16758 argument of the call is compared with the type P of the
16759 declarator-id of the function parameter pack. */
16765 /* For a function parameter pack that does not occur at the
16766 end of the parameter-declaration-list, the type of the
16767 parameter pack is a non-deduced context. */
16776 }
16781 {
16782 /* Unify the remaining arguments with the pack expansion type. */
16783 tree argvec;
16786 /* Allocate a TREE_VEC and copy in all of the arguments */
16791 /* Copy the parameter into parmvec. */
16797 /* Advance to the end of the list of parameters. */
16799 }
16801 /* Fail if we've reached the end of the parm list, and more args
16802 are present, and the parm list isn't variadic. */
16805 /* Fail if parms are left and they don't have default values and
16806 they aren't all deduced as empty packs (c++/57397). This is
16807 consistent with sufficient_parms_p. */
16810 {
16814 do
16815 {
16818 count++;
16820 }
16824 type_pack_p);
16825 }
16828 {
16829 tsubst_flags_t complain = (explain_p
16830 ? tf_warning_or_error
16834 {
16838 /* Clear the "incomplete" flags on all argument packs now so that
16839 substituting them into later default arguments works. */
16841 {
16844 }
16850 /* If this is an undeduced nontype parameter that depends on
16851 a type parameter, try another pass; its type may have been
16852 deduced from a later argument than the one from which
16853 this parameter can be deduced. */
16859 /* Core issue #226 (C++0x) [temp.deduct]:
16861 If a template argument has not been deduced, its
16862 default template argument, if any, is used.
16864 When we are in C++98 mode, TREE_PURPOSE will either
16865 be NULL_TREE or ERROR_MARK_NODE, so we do not need
16866 to explicitly check cxx_dialect here. */
16868 {
16883 else
16884 {
16886 /* The position of the first default template argument,
16887 is also the number of non-defaulted arguments in TARGS.
16888 Record that. */
16892 }
16893 }
16895 /* If the type parameter is a parameter pack, then it will
16896 be deduced to an empty parameter pack. */
16898 {
16899 tree arg;
16902 {
16906 }
16907 else
16914 }
16917 }
16918 }
16919 #ifdef ENABLE_CHECKING
16922 #endif
16925 }
16927 /* Subroutine of type_unification_real. Args are like the variables
16928 at the call site. ARG is an overloaded function (or template-id);
16929 we try deducing template args from each of the overloads, and if
16930 only one succeeds, we go with that. Modifies TARGS and returns
16931 true on success. */
16933 static bool
16935 tree targs,
16936 tree parm,
16937 tree arg,
16938 unification_kind_t strict,
16941 {
16948 {
16951 }
16952 else
16956 /* Handle `&x' where `x' is some static or non-static member
16957 function name. */
16963 /* Strip baselink information. */
16968 {
16969 /* If we got some explicit template args, we need to plug them into
16970 the affected templates before we try to unify, in case the
16971 explicit args will completely resolve the templates in question. */
16978 {
16991 {
16996 {
16999 }
17000 }
17003 }
17004 /* If no templates (or more than one) are fully resolved by the
17005 explicit arguments, this template-id is a non-deduced context; it
17006 could still be OK if we deduce all template arguments for the
17007 enclosing call through other arguments. */
17010 }
17013 /* If ARG is, for example, "(0, &f)" then its type will be unknown
17014 -- but the deduction does not succeed because the expression is
17015 not just the function on its own. */
17017 else
17023 {
17026 }
17028 /* [temp.deduct.type] A template-argument can be deduced from a pointer
17029 to function or pointer to member function argument if the set of
17030 overloaded functions does not contain function templates and at most
17031 one of a set of overloaded functions provides a unique match.
17033 So if we found multiple possibilities, we return success but don't
17034 deduce anything. */
17037 {
17041 {
17046 /* Don't forget explicit template arguments in a pack. */
17050 }
17051 }
17056 }
17058 /* Core DR 115: In contexts where deduction is done and fails, or in
17059 contexts where deduction is not done, if a template argument list is
17060 specified and it, along with any default template arguments, identifies
17061 a single function template specialization, then the template-id is an
17062 lvalue for the function template specialization. */
17064 tree
17066 {
17079 {
17082 }
17084 {
17087 }
17089 {
17092 }
17095 {
17099 /* If we got some explicit template args, we need to plug them into
17100 the affected templates before we try to unify, in case the
17101 explicit args will completely resolve the templates in question. */
17109 {
17122 {
17125 {
17128 }
17130 {
17133 }
17134 }
17135 }
17137 {
17145 {
17146 tree base
17149 }
17153 }
17155 /* There were no good options and at least one bad one, so let the
17156 user know what the problem is. */
17158 }
17160 }
17162 /* Subroutine of resolve_overloaded_unification; does deduction for a single
17163 overload. Fills TARGS with any deduced arguments, or error_mark_node if
17164 different overloads deduce different arguments for a given parm.
17165 ADDR_P is true if the expression for which deduction is being
17166 performed was of the form "& fn" rather than simply "fn".
17168 Returns 1 on success. */
17170 static int
17172 tree orig_targs,
17173 tree targs,
17174 tree parm,
17175 tree arg,
17176 unification_kind_t strict,
17180 {
17182 tree tempargs;
17188 /* [temp.deduct.type] A template-argument can be deduced from a pointer
17189 to function or pointer to member function argument if the set of
17190 overloaded functions does not contain function templates and at most
17191 one of a set of overloaded functions provides a unique match.
17193 So if this is a template, just return success. */
17205 /* We don't copy orig_targs for this because if we have already deduced
17206 some template args from previous args, unify would complain when we
17207 try to deduce a template parameter for the same argument, even though
17208 there isn't really a conflict. */
17215 /* First make sure we didn't deduce anything that conflicts with
17216 explicitly specified args. */
17218 {
17225 /* Since we're unifying against ourselves, we will fill in
17226 template args used in the function parm list with our own
17227 template parms. Discard them. */
17231 }
17234 {
17239 }
17242 }
17244 /* PARM is a template class (perhaps with unbound template
17245 parameters). ARG is a fully instantiated type. If ARG can be
17246 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
17247 TARGS are as for unify. */
17249 static tree
17252 {
17253 tree copy_of_targs;
17260 /* We need to make a new template argument vector for the call to
17261 unify. If we used TARGS, we'd clutter it up with the result of
17262 the attempted unification, even if this class didn't work out.
17263 We also don't want to commit ourselves to all the unifications
17264 we've already done, since unification is supposed to be done on
17265 an argument-by-argument basis. In other words, consider the
17266 following pathological case:
17268 template <int I, int J, int K>
17269 struct S {};
17271 template <int I, int J>
17272 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
17274 template <int I, int J, int K>
17275 void f(S<I, J, K>, S<I, I, I>);
17277 void g() {
17278 S<0, 0, 0> s0;
17279 S<0, 1, 2> s2;
17281 f(s0, s2);
17282 }
17284 Now, by the time we consider the unification involving `s2', we
17285 already know that we must have `f<0, 0, 0>'. But, even though
17286 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
17287 because there are two ways to unify base classes of S<0, 1, 2>
17288 with S<I, I, I>. If we kept the already deduced knowledge, we
17289 would reject the possibility I=1. */
17292 /* If unification failed, we're done. */
17298 }
17300 /* Given a template type PARM and a class type ARG, find the unique
17301 base type in ARG that is an instance of PARM. We do not examine
17302 ARG itself; only its base-classes. If there is not exactly one
17303 appropriate base class, return NULL_TREE. PARM may be the type of
17304 a partial specialization, as well as a plain template type. Used
17305 by unify. */
17307 static enum template_base_result
17310 {
17312 tree binfo;
17318 {
17319 /* The type could not be completed. */
17322 }
17324 /* Walk in inheritance graph order. The search order is not
17325 important, and this avoids multiple walks of virtual bases. */
17327 {
17332 {
17333 /* If there is more than one satisfactory baseclass, then:
17335 [temp.deduct.call]
17337 If they yield more than one possible deduced A, the type
17338 deduction fails.
17340 applies. */
17342 {
17345 }
17348 }
17349 }
17353 }
17355 /* Returns the level of DECL, which declares a template parameter. */
17357 static int
17359 {
17361 {
17371 }
17373 }
17375 /* Decide whether ARG can be unified with PARM, considering only the
17376 cv-qualifiers of each type, given STRICT as documented for unify.
17377 Returns nonzero iff the unification is OK on that basis. */
17379 static int
17381 {
17387 {
17388 /* Although a CVR qualifier is ignored when being applied to a
17389 substituted template parameter ([8.3.2]/1 for example), that
17390 does not allow us to unify "const T" with "int&" because both
17391 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
17392 It is ok when we're allowing additional CV qualifiers
17393 at the outer level [14.8.2.1]/3,1st bullet. */
17403 }
17414 }
17416 /* Determines the LEVEL and INDEX for the template parameter PARM. */
17417 void
17419 {
17423 {
17426 }
17427 else
17428 {
17431 }
17432 }
17434 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
17435 do { \
17436 if (unify (TP, TA, P, A, S, EP)) \
17437 return 1; \
17438 } while (0);
17440 /* Unifies the remaining arguments in PACKED_ARGS with the pack
17441 expansion at the end of PACKED_PARMS. Returns 0 if the type
17442 deduction succeeds, 1 otherwise. STRICT is the same as in
17443 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
17444 call argument list. We'll need to adjust the arguments to make them
17445 types. SUBR tells us if this is from a recursive call to
17446 type_unification_real, or for comparing two template argument
17447 lists. */
17449 static int
17453 {
17454 tree parm
17464 /* Determine the parameter packs we will be deducing from the
17465 pattern, and record their current deductions. */
17468 {
17472 /* Determine the index and level of this parameter pack. */
17475 /* Keep track of the parameter packs and their corresponding
17476 argument packs. */
17479 }
17481 /* Loop through all of the arguments that have not yet been
17482 unified and unify each with the pattern. */
17484 {
17485 tree parm;
17489 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
17490 or the element of its argument pack at the current index if
17491 this argument was explicitly specified. */
17493 {
17502 {
17505 }
17507 }
17509 /* If we had explicit template arguments, substitute them into the
17510 pattern before deduction. */
17512 {
17513 /* Some arguments might still be unspecified or dependent. */
17521 NULL_TREE);
17526 }
17527 else
17530 /* Unify the pattern with the current argument. */
17535 /* For each parameter pack, collect the deduced value. */
17537 {
17543 }
17544 }
17546 /* Verify that the results of unification with the parameter packs
17547 produce results consistent with what we've seen before, and make
17548 the deduced argument packs available. */
17550 {
17557 /* By default keep the original deduced argument pack.
17558 If necessary, more specific code is going to update the
17559 resulting deduced argument later down in this function. */
17563 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
17564 actually deduce anything. */
17572 {
17573 /* If we had fewer function args than explicit template args,
17574 just use the explicits. */
17579 }
17582 {
17583 tree result;
17584 /* Build the deduced *_ARGUMENT_PACK. */
17586 {
17591 }
17592 else
17597 /* Note the deduced argument packs for this parameter
17598 pack. */
17600 }
17604 {
17605 /* We only had the explicitly-provided arguments before, but
17606 now we have a complete set of arguments. */
17612 }
17613 else
17614 {
17620 /* Inconsistent unification of this parameter pack. */
17622 bad_old_arg,
17623 bad_new_arg);
17624 }
17625 }
17628 }
17630 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
17631 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
17632 parameters and return value are as for unify. */
17634 static int
17638 {
17639 tree parm_max;
17640 tree arg_max;
17644 /* Our representation of array types uses "N - 1" as the
17645 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
17646 not an integer constant. We cannot unify arbitrarily
17647 complex expressions, so we eliminate the MINUS_EXPRs
17648 here. */
17652 {
17655 }
17659 {
17660 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
17661 trying to unify the type of a variable with the type
17662 of a template parameter. For example:
17664 template <unsigned int N>
17665 void f (char (&) [N]);
17666 int g();
17667 void h(int i) {
17668 char a[g(i)];
17669 f(a);
17670 }
17672 Here, the type of the ARG will be "int [g(i)]", and
17673 may be a SAVE_EXPR, etc. */
17677 }
17679 /* If only one of the bounds used a MINUS_EXPR, compensate
17680 by adding one to the other bound. */
17683 integer_type_node,
17684 parm_max,
17685 integer_one_node);
17688 integer_type_node,
17689 arg_max,
17690 integer_one_node);
17694 }
17696 /* Deduce the value of template parameters. TPARMS is the (innermost)
17697 set of template parameters to a template. TARGS is the bindings
17698 for those template parameters, as determined thus far; TARGS may
17699 include template arguments for outer levels of template parameters
17700 as well. PARM is a parameter to a template function, or a
17701 subcomponent of that parameter; ARG is the corresponding argument.
17702 This function attempts to match PARM with ARG in a manner
17703 consistent with the existing assignments in TARGS. If more values
17704 are deduced, then TARGS is updated.
17706 Returns 0 if the type deduction succeeds, 1 otherwise. The
17707 parameter STRICT is a bitwise or of the following flags:
17709 UNIFY_ALLOW_NONE:
17710 Require an exact match between PARM and ARG.
17711 UNIFY_ALLOW_MORE_CV_QUAL:
17712 Allow the deduced ARG to be more cv-qualified (by qualification
17713 conversion) than ARG.
17714 UNIFY_ALLOW_LESS_CV_QUAL:
17715 Allow the deduced ARG to be less cv-qualified than ARG.
17716 UNIFY_ALLOW_DERIVED:
17717 Allow the deduced ARG to be a template base class of ARG,
17718 or a pointer to a template base class of the type pointed to by
17719 ARG.
17720 UNIFY_ALLOW_INTEGER:
17721 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
17722 case for more information.
17723 UNIFY_ALLOW_OUTER_LEVEL:
17724 This is the outermost level of a deduction. Used to determine validity
17725 of qualification conversions. A valid qualification conversion must
17726 have const qualified pointers leading up to the inner type which
17727 requires additional CV quals, except at the outer level, where const
17728 is not required [conv.qual]. It would be normal to set this flag in
17729 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
17730 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
17731 This is the outermost level of a deduction, and PARM can be more CV
17732 qualified at this point.
17733 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
17734 This is the outermost level of a deduction, and PARM can be less CV
17735 qualified at this point. */
17737 static int
17740 {
17742 tree targ;
17743 tree tparm;
17746 /* I don't think this will do the right thing with respect to types.
17747 But the only case I've seen it in so far has been array bounds, where
17748 signedness is the only information lost, and I think that will be
17749 okay. */
17757 /* We can't deduce anything from this, but we might get all the
17758 template args from other function args. */
17761 /* If PARM uses template parameters, then we can't bail out here,
17762 even if ARG == PARM, since we won't record unifications for the
17763 template parameters. We might need them if we're trying to
17764 figure out which of two things is more specialized. */
17768 /* Handle init lists early, so the rest of the function can assume
17769 we're dealing with a type. */
17771 {
17776 /* Replace T with std::initializer_list<T> for deduction. */
17783 /* We can only deduce from an initializer list argument if the
17784 parameter is std::initializer_list or an array; otherwise this
17785 is a non-deduced context. */
17790 else
17794 {
17801 {
17803 /* It should only be possible to get here for a call. */
17805 elt_strict |= maybe_adjust_types_for_deduction
17808 }
17811 explain_p);
17812 }
17816 {
17817 /* Also deduce from the length of the initializer list. */
17824 }
17826 /* If the std::initializer_list<T> deduction worked, replace the
17827 deduced A with std::initializer_list<A>. */
17829 {
17834 }
17836 }
17838 /* Immediately reject some pairs that won't unify because of
17839 cv-qualification mismatches. */
17842 /* It is the elements of the array which hold the cv quals of an array
17843 type, and the elements might be template type parms. We'll check
17844 when we recurse. */
17846 /* We check the cv-qualifiers when unifying with template type
17847 parameters below. We want to allow ARG `const T' to unify with
17848 PARM `T' for example, when computing which of two templates
17849 is more specialized, for example. */
17863 {
17867 /* In a type which contains a nested-name-specifier, template
17868 argument values cannot be deduced for template parameters used
17869 within the nested-name-specifier. */
17881 /* The PARM is not one we're trying to unify. Just check
17882 to see if it matches ARG. */
17883 {
17888 else
17890 }
17897 /* Check for mixed types and values. */
17905 {
17906 /* ARG must be constructed from a template class or a template
17907 template parameter. */
17911 {
17913 /* An alias template name is never deduced. */
17918 tree parm_parms
17919 = DECL_INNERMOST_TEMPLATE_PARMS
17924 /* The resolution to DR150 makes clear that default
17925 arguments for an N-argument may not be used to bind T
17926 to a template template parameter with fewer than N
17927 parameters. It is not safe to permit the binding of
17928 default arguments as an extension, as that may change
17929 the meaning of a conforming program. Consider:
17931 struct Dense { static const unsigned int dim = 1; };
17933 template <template <typename> class View,
17934 typename Block>
17935 void operator+(float, View<Block> const&);
17937 template <typename Block,
17938 unsigned int Dim = Block::dim>
17939 struct Lvalue_proxy { operator float() const; };
17941 void
17942 test_1d (void) {
17943 Lvalue_proxy<Dense> p;
17944 float b;
17945 b + p;
17946 }
17948 Here, if Lvalue_proxy is permitted to bind to View, then
17949 the global operator+ will be used; if they are not, the
17950 Lvalue_proxy will be converted to float. */
17952 full_argvec,
17954 (explain_p
17955 ? tf_warning_or_error
17962 /* Deduce arguments T, i from TT<T> or TT<i>.
17963 We check each element of PARMVEC and ARGVEC individually
17964 rather than the whole TREE_VEC since they can have
17965 different number of elements. */
17972 /* Check if the parameters end in a pack, making them
17973 variadic. */
17979 /* If the template argument list of P contains a pack
17980 expansion that is not the last template argument, the
17981 entire template argument list is a non-deduced
17982 context. */
17991 {
17996 }
18001 DEDUCE_EXACT,
18004 }
18007 /* Fall through to deduce template name. */
18008 }
18012 {
18013 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
18015 /* Simple cases: Value already set, does match or doesn't. */
18020 }
18021 else
18022 {
18023 /* If PARM is `const T' and ARG is only `int', we don't have
18024 a match unless we are allowing additional qualification.
18025 If ARG is `const int' and PARM is just `T' that's OK;
18026 that binds `const int' to `T'. */
18031 /* Consider the case where ARG is `const volatile int' and
18032 PARM is `const T'. Then, T should be `volatile int'. */
18033 arg = cp_build_qualified_type_real
18038 /* Simple cases: Value already set, does match or doesn't. */
18044 /* Make sure that ARG is not a variable-sized array. (Note
18045 that were talking about variable-sized arrays (like
18046 `int[n]'), rather than arrays of unknown size (like
18047 `int[]').) We'll get very confused by such a type since
18048 the bound of the array is not constant, and therefore
18049 not mangleable. Besides, such types are not allowed in
18050 ISO C++, so we can do as we please here. We do allow
18051 them for 'auto' deduction, since that isn't ABI-exposed. */
18055 /* Strip typedefs as in convert_template_argument. */
18057 }
18059 /* If ARG is a parameter pack or an expansion, we cannot unify
18060 against it unless PARM is also a parameter pack. */
18065 /* If the argument deduction results is a METHOD_TYPE,
18066 then there is a problem.
18067 METHOD_TYPE doesn't map to any real C++ type the result of
18068 the deduction can not be of that type. */
18082 {
18083 /* The PARM is not one we're trying to unify. Just check
18084 to see if it matches ARG. */
18090 }
18096 {
18101 }
18103 /* [temp.deduct.type] If, in the declaration of a function template
18104 with a non-type template-parameter, the non-type
18105 template-parameter is used in an expression in the function
18106 parameter-list and, if the corresponding template-argument is
18107 deduced, the template-argument type shall match the type of the
18108 template-parameter exactly, except that a template-argument
18109 deduced from an array bound may be of any integral type.
18110 The non-type parameter might use already deduced type parameters. */
18113 /* Template-parameter dependent expression. Just accept it for now.
18114 It will later be processed in convert_template_argument. */
18115 ;
18120 /* Convert the ARG to the type of PARM; the deduced non-type
18121 template argument must exactly match the types of the
18122 corresponding parameter. */
18125 /* We haven't deduced the type of this parameter yet. Try again
18126 later. */
18128 else
18131 /* If ARG is a parameter pack or an expansion, we cannot unify
18132 against it unless PARM is also a parameter pack. */
18142 {
18143 /* A pointer-to-member constant can be unified only with
18144 another constant. */
18148 /* Just unify the class member. It would be useless (and possibly
18149 wrong, depending on the strict flags) to unify also
18150 PTRMEM_CST_CLASS, because we want to be sure that both parm and
18151 arg refer to the same variable, even if through different
18152 classes. For instance:
18154 struct A { int x; };
18155 struct B : A { };
18157 Unification of &A::x and &B::x must succeed. */
18160 }
18163 {
18167 /* [temp.deduct.call]
18169 A can be another pointer or pointer to member type that can
18170 be converted to the deduced A via a qualification
18171 conversion (_conv.qual_).
18173 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
18174 This will allow for additional cv-qualification of the
18175 pointed-to types if appropriate. */
18178 /* The derived-to-base conversion only persists through one
18179 level of pointers. */
18184 }
18216 /* We have already checked cv-qualification at the top of the
18217 function. */
18221 /* As far as unification is concerned, this wins. Later checks
18222 will invalidate it if necessary. */
18225 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
18226 /* Type INTEGER_CST can come from ordinary constant template args. */
18238 {
18248 /* Check for pack expansions in the parameters. */
18250 {
18252 {
18254 /* We can unify against something with a trailing
18255 parameter pack. */
18257 else
18258 /* [temp.deduct.type]/9: If the template argument list of
18259 P contains a pack expansion that is not the last
18260 template argument, the entire template argument list
18261 is a non-deduced context. */
18263 }
18264 }
18266 /* If we don't have enough arguments to satisfy the parameters
18267 (not counting the pack expression at the end), or we have
18268 too many arguments for a parameter list that doesn't end in
18269 a pack expression, we can't unify. */
18275 /* Unify all of the parameters that precede the (optional)
18276 pack expression. */
18278 {
18283 }
18286 DEDUCE_EXACT,
18289 }
18297 {
18305 }
18310 {
18314 {
18315 /* First, we try to unify the PARM and ARG directly. */
18320 {
18321 /* Fallback to the special case allowed in
18322 [temp.deduct.call]:
18324 If P is a class, and P has the form
18325 template-id, then A can be a derived class of
18326 the deduced A. Likewise, if P is a pointer to
18327 a class of the form template-id, A can be a
18328 pointer to a derived class pointed to by the
18329 deduced A. */
18336 }
18337 }
18341 /* Perhaps PARM is something like S<U> and ARG is S<int>.
18342 Then, we should unify `int' and `U'. */
18344 else
18345 /* There's no chance of unification succeeding. */
18350 }
18357 {
18360 tree a;
18366 /* CV qualifications for methods can never be deduced, they must
18367 match exactly. We need to check them explicitly here,
18368 because type_unification_real treats them as any other
18369 cv-qualified parameter. */
18371 && (!check_cv_quals_for_unify
18391 }
18394 /* Unify a pointer to member with a pointer to member function, which
18395 deduces the type of the member as a function type. */
18397 {
18398 /* Check top-level cv qualifiers */
18406 /* Determine the type of the function we are unifying against. */
18410 }
18429 /* Matched cases are handled by the ARG == PARM test above. */
18433 /* A non-type template parameter that is a variable should be a
18434 an integral constant, in which case, it whould have been
18435 folded into its (constant) value. So we should not be getting
18436 a variable here. */
18447 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
18448 or UNDERLYING_TYPE nodes. */
18452 /* Unification fails if we hit an error node. */
18459 /* FALLTHRU */
18462 /* An unresolved overload is a nondeduced context. */
18467 /* We must be looking at an expression. This can happen with
18468 something like:
18470 template <int I>
18471 void foo(S<I>, S<I + 2>);
18473 This is a "nondeduced context":
18475 [deduct.type]
18477 The nondeduced contexts are:
18479 --A type that is a template-id in which one or more of
18480 the template-arguments is an expression that references
18481 a template-parameter.
18483 In these cases, we assume deduction succeeded, but don't
18484 actually infer any unifications. */
18489 else
18491 }
18492 }
18493 #undef RECUR_AND_CHECK_FAILURE
18494 \f
18495 /* Note that DECL can be defined in this translation unit, if
18496 required. */
18498 static void
18500 {
18501 tree clone;
18505 }
18507 /* Called if RESULT is explicitly instantiated, or is a member of an
18508 explicitly instantiated class. */
18510 void
18512 {
18515 /* If this entity has already been written out, it's too late to
18516 make any modifications. */
18520 /* For anonymous namespace we don't need to do anything. */
18522 {
18525 }
18528 /* The TREE_PUBLIC flag for function declarations will have been
18529 set correctly by tsubst. */
18532 /* This might have been set by an earlier implicit instantiation. */
18537 else
18538 {
18541 /* Always make artificials weak. */
18544 /* For WIN32 we also want to put explicit instantiations in
18545 linkonce sections. */
18548 }
18550 /* If EXTERN_P, then this function will not be emitted -- unless
18551 followed by an explicit instantiation, at which point its linkage
18552 will be adjusted. If !EXTERN_P, then this function will be
18553 emitted here. In neither circumstance do we want
18554 import_export_decl to adjust the linkage. */
18556 }
18558 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
18559 important template arguments. If any are missing, we check whether
18560 they're important by using error_mark_node for substituting into any
18561 args that were used for partial ordering (the ones between ARGS and END)
18562 and seeing if it bubbles up. */
18564 static bool
18566 {
18571 {
18574 }
18576 {
18580 }
18582 }
18584 /* Given two function templates PAT1 and PAT2, return:
18586 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
18587 -1 if PAT2 is more specialized than PAT1.
18588 0 if neither is more specialized.
18590 LEN indicates the number of parameters we should consider
18591 (defaulted parameters should not be considered).
18593 The 1998 std underspecified function template partial ordering, and
18594 DR214 addresses the issue. We take pairs of arguments, one from
18595 each of the templates, and deduce them against each other. One of
18596 the templates will be more specialized if all the *other*
18597 template's arguments deduce against its arguments and at least one
18598 of its arguments *does* *not* deduce against the other template's
18599 corresponding argument. Deduction is done as for class templates.
18600 The arguments used in deduction have reference and top level cv
18601 qualifiers removed. Iff both arguments were originally reference
18602 types *and* deduction succeeds in both directions, an lvalue reference
18603 wins against an rvalue reference and otherwise the template
18604 with the more cv-qualified argument wins for that pairing (if
18605 neither is more cv-qualified, they both are equal). Unlike regular
18606 deduction, after all the arguments have been deduced in this way,
18607 we do *not* verify the deduced template argument values can be
18608 substituted into non-deduced contexts.
18610 The logic can be a bit confusing here, because we look at deduce1 and
18611 targs1 to see if pat2 is at least as specialized, and vice versa; if we
18612 can find template arguments for pat1 to make arg1 look like arg2, that
18613 means that arg2 is at least as specialized as arg1. */
18615 int
18617 {
18630 /* Remove the this parameter from non-static member functions. If
18631 one is a non-static member function and the other is not a static
18632 member function, remove the first parameter from that function
18633 also. This situation occurs for operator functions where we
18634 locate both a member function (with this pointer) and non-member
18635 operator (with explicit first operand). */
18637 {
18642 }
18644 {
18647 {
18648 len--;
18650 }
18651 }
18653 /* If only one is a conversion operator, they are unordered. */
18657 /* Consider the return type for a conversion function */
18659 {
18662 len++;
18663 }
18665 processing_template_decl++;
18671 /* Stop when an ellipsis is seen. */
18673 {
18684 {
18685 /* When both arguments are pack expansions, we need only
18686 unify the patterns themselves. */
18690 /* This is the last comparison we need to do. */
18692 }
18695 {
18699 }
18702 {
18706 }
18712 {
18718 /* Setup the parameter vector, which contains only ARG1. */
18721 /* Setup the argument vector, which contains the remaining
18722 arguments. */
18731 /* We cannot deduce in the other direction, because ARG1 is
18732 a pack expansion but ARG2 is not. */
18734 }
18736 {
18742 /* Setup the parameter vector, which contains only ARG1. */
18745 /* Setup the argument vector, which contains the remaining
18746 arguments. */
18755 /* We cannot deduce in the other direction, because ARG2 is
18756 a pack expansion but ARG1 is not.*/
18758 }
18760 else
18761 {
18762 /* The normal case, where neither argument is a pack
18763 expansion. */
18770 }
18772 /* If we couldn't deduce arguments for tparms1 to make arg1 match
18773 arg2, then arg2 is not as specialized as arg1. */
18779 /* "If, for a given type, deduction succeeds in both directions
18780 (i.e., the types are identical after the transformations above)
18781 and both P and A were reference types (before being replaced with
18782 the type referred to above):
18783 - if the type from the argument template was an lvalue reference and
18784 the type from the parameter template was not, the argument type is
18785 considered to be more specialized than the other; otherwise,
18786 - if the type from the argument template is more cv-qualified
18787 than the type from the parameter template (as described above),
18788 the argument type is considered to be more specialized than the other;
18789 otherwise,
18790 - neither type is more specialized than the other." */
18793 {
18795 {
18798 else
18800 }
18802 {
18807 }
18808 }
18811 /* We've failed to deduce something in either direction.
18812 These must be unordered. */
18817 /* We have already processed all of the arguments in our
18818 handing of the pack expansion type. */
18823 }
18825 /* "In most cases, all template parameters must have values in order for
18826 deduction to succeed, but for partial ordering purposes a template
18827 parameter may remain without a value provided it is not used in the
18828 types being used for partial ordering."
18830 Thus, if we are missing any of the targs1 we need to substitute into
18831 origs1, then pat2 is not as specialized as pat1. This can happen when
18832 there is a nondeduced context. */
18838 processing_template_decl--;
18840 /* All things being equal, if the next argument is a pack expansion
18841 for one function but not for the other, prefer the
18842 non-variadic function. FIXME this is bogus; see c++/41958. */
18846 {
18849 }
18855 else
18857 }
18859 /* Determine which of two partial specializations of TMPL is more
18860 specialized.
18862 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
18863 to the first partial specialization. The TREE_VALUE is the
18864 innermost set of template parameters for the partial
18865 specialization. PAT2 is similar, but for the second template.
18867 Return 1 if the first partial specialization is more specialized;
18868 -1 if the second is more specialized; 0 if neither is more
18869 specialized.
18871 See [temp.class.order] for information about determining which of
18872 two templates is more specialized. */
18874 static int
18876 {
18877 tree targs;
18885 /* Just like what happens for functions, if we are ordering between
18886 different class template specializations, we may encounter dependent
18887 types in the arguments, and we need our dependency check functions
18888 to behave correctly. */
18894 {
18897 }
18903 {
18906 }
18909 /* In the case of a tie where at least one of the class templates
18910 has a parameter pack at the end, the template with the most
18911 non-packed parameters wins. */
18913 && any_deductions
18916 {
18922 /* We don't count the pack expansion at the end. */
18932 }
18935 }
18937 /* Return the template arguments that will produce the function signature
18938 DECL from the function template FN, with the explicit template
18939 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
18940 also match. Return NULL_TREE if no satisfactory arguments could be
18941 found. */
18943 static tree
18945 {
18949 tree decl_arg_types;
18952 tree arg;
18956 /* Never do unification on the 'this' parameter. */
18977 }
18979 /* Return the innermost template arguments that, when applied to a partial
18980 specialization of TMPL whose innermost template parameters are
18981 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
18982 ARGS.
18984 For example, suppose we have:
18986 template <class T, class U> struct S {};
18987 template <class T> struct S<T*, int> {};
18989 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
18990 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
18991 int}. The resulting vector will be {double}, indicating that `T'
18992 is bound to `double'. */
18994 static tree
18996 {
18998 tree deduced_args;
18999 tree innermost_deduced_args;
19003 {
19007 innermost_deduced_args);
19008 }
19009 else
19022 /* Verify that nondeduced template arguments agree with the type
19023 obtained from argument deduction.
19025 For example:
19027 struct A { typedef int X; };
19028 template <class T, class U> struct C {};
19029 template <class T> struct C<T, typename T::X> {};
19031 Then with the instantiation `C<A, int>', we can deduce that
19032 `T' is `A' but unify () does not check whether `typename T::X'
19033 is `int'. */
19039 /* We only need to check the innermost arguments; the other
19040 arguments will always agree. */
19045 /* Now that we have bindings for all of the template arguments,
19046 ensure that the arguments deduced for the template template
19047 parameters have compatible template parameter lists. See the use
19048 of template_template_parm_bindings_ok_p in fn_type_unification
19049 for more information. */
19054 }
19056 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
19057 Return the TREE_LIST node with the most specialized template, if
19058 any. If there is no most specialized template, the error_mark_node
19059 is returned.
19061 Note that this function does not look at, or modify, the
19062 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
19063 returned is one of the elements of INSTANTIATIONS, callers may
19064 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
19065 and retrieve it from the value returned. */
19067 tree
19069 {
19076 {
19082 fate--;
19087 fate++;
19092 {
19093 /* Equally specialized, move to next function. If there
19094 is no next function, nothing's most specialized. */
19099 }
19100 }
19103 /* Now verify that champ is better than everything earlier in the
19104 instantiation list. */
19112 {
19115 }
19117 processing_template_decl--;
19123 }
19125 /* If DECL is a specialization of some template, return the most
19126 general such template. Otherwise, returns NULL_TREE.
19128 For example, given:
19130 template <class T> struct S { template <class U> void f(U); };
19132 if TMPL is `template <class U> void S<int>::f(U)' this will return
19133 the full template. This function will not trace past partial
19134 specializations, however. For example, given in addition:
19136 template <class T> struct S<T*> { template <class U> void f(U); };
19138 if TMPL is `template <class U> void S<int*>::f(U)' this will return
19139 `template <class T> template <class U> S<T*>::f(U)'. */
19141 tree
19143 {
19145 {
19148 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
19149 template friend, or a FIELD_DECL for a capture pack. */
19152 }
19154 /* Look for more and more general templates. */
19156 {
19157 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
19158 (See cp-tree.h for details.) */
19166 /* Stop if we run into an explicitly specialized class template. */
19173 }
19176 }
19178 /* Return the most specialized of the class template partial
19179 specializations which can produce TYPE, a specialization of some class
19180 template. The value returned is actually a TREE_LIST; the TREE_TYPE is
19181 a _TYPE node corresponding to the partial specialization, while the
19182 TREE_PURPOSE is the set of template arguments that must be
19183 substituted into the TREE_TYPE in order to generate TYPE.
19185 If the choice of partial specialization is ambiguous, a diagnostic
19186 is issued, and the error_mark_node is returned. If there are no
19187 partial specializations matching TYPE, then NULL_TREE is
19188 returned, indicating that the primary template should be used. */
19190 static tree
19192 {
19194 tree t;
19195 tree champ;
19204 /* For determining which partial specialization to use, only the
19205 innermost args are interesting. */
19207 {
19210 }
19213 {
19214 tree partial_spec_args;
19215 tree spec_args;
19224 {
19225 /* Discard the outer levels of args, and then substitute in the
19226 template args from the enclosing class. */
19228 partial_spec_args = tsubst_template_args
19231 /* And the same for the partial specialization TEMPLATE_DECL. */
19233 }
19235 partial_spec_args =
19237 partial_spec_args,
19251 partial_spec_args,
19252 args);
19254 {
19259 }
19260 }
19270 {
19273 ;
19274 else
19275 {
19277 {
19280 {
19283 }
19284 }
19286 }
19287 }
19291 {
19294 {
19297 }
19298 }
19301 {
19309 {
19312 }
19315 }
19318 }
19320 /* Explicitly instantiate DECL. */
19322 void
19324 {
19329 /* An error occurred, for which grokdeclarator has already issued
19330 an appropriate message. */
19333 {
19336 }
19342 {
19343 /* There is an asymmetry here in the way VAR_DECLs and
19344 FUNCTION_DECLs are handled by grokdeclarator. In the case of
19345 the latter, the DECL we get back will be marked as a
19346 template instantiation, and the appropriate
19347 DECL_TEMPLATE_INFO will be set up. This does not happen for
19348 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
19349 should handle VAR_DECLs as it currently handles
19350 FUNCTION_DECLs. */
19352 {
19355 }
19358 {
19361 }
19363 {
19368 }
19369 }
19371 {
19374 }
19375 else
19378 /* Check for various error cases. Note that if the explicit
19379 instantiation is valid the RESULT will currently be marked as an
19380 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
19381 until we get here. */
19384 {
19385 /* DR 259 [temp.spec].
19387 Both an explicit instantiation and a declaration of an explicit
19388 specialization shall not appear in a program unless the explicit
19389 instantiation follows a declaration of the explicit specialization.
19391 For a given set of template parameters, if an explicit
19392 instantiation of a template appears after a declaration of an
19393 explicit specialization for that template, the explicit
19394 instantiation has no effect. */
19396 }
19398 {
19399 /* [temp.spec]
19401 No program shall explicitly instantiate any template more
19402 than once.
19404 We check DECL_NOT_REALLY_EXTERN so as not to complain when
19405 the first instantiation was `extern' and the second is not,
19406 and EXTERN_P for the opposite case. */
19409 /* If an "extern" explicit instantiation follows an ordinary
19410 explicit instantiation, the template is instantiated. */
19413 }
19415 {
19418 }
19420 {
19423 }
19426 ;
19428 {
19431 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
19434 }
19435 else
19443 }
19445 static void
19447 {
19453 {
19456 }
19457 }
19459 /* Called from do_type_instantiation through binding_table_foreach to
19460 do recursive instantiation for the type bound in ENTRY. */
19461 static void
19463 {
19469 }
19471 /* Called from do_type_instantiation to instantiate a member
19472 (a member function or a static member variable) of an
19473 explicitly instantiated class template. */
19474 static void
19476 {
19481 }
19483 /* Perform an explicit instantiation of template class T. STORAGE, if
19484 non-null, is the RID for extern, inline or static. COMPLAIN is
19485 nonzero if this is called from the parser, zero if called recursively,
19486 since the standard is unclear (as detailed below). */
19488 void
19490 {
19500 {
19501 tree tmpl =
19505 else
19508 }
19513 {
19516 t);
19518 }
19521 {
19523 {
19525 {
19528 "ISO C++ 1998 forbids the use of %<extern%> on "
19530 }
19531 else
19533 "ISO C++ forbids the use of %qE"
19535 }
19543 else
19544 {
19546 storage);
19548 }
19549 }
19552 {
19553 /* DR 259 [temp.spec].
19555 Both an explicit instantiation and a declaration of an explicit
19556 specialization shall not appear in a program unless the explicit
19557 instantiation follows a declaration of the explicit specialization.
19559 For a given set of template parameters, if an explicit
19560 instantiation of a template appears after a declaration of an
19561 explicit specialization for that template, the explicit
19562 instantiation has no effect. */
19564 }
19566 {
19567 /* [temp.spec]
19569 No program shall explicitly instantiate any template more
19570 than once.
19572 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
19573 instantiation was `extern'. If EXTERN_P then the second is.
19574 These cases are OK. */
19581 /* If we've already instantiated the template, just return now. */
19584 }
19592 {
19593 tree tmp;
19595 /* In contrast to implicit instantiation, where only the
19596 declarations, and not the definitions, of members are
19597 instantiated, we have here:
19599 [temp.explicit]
19601 The explicit instantiation of a class template specialization
19602 implies the instantiation of all of its members not
19603 previously explicitly specialized in the translation unit
19604 containing the explicit instantiation.
19606 Of course, we can't instantiate member template classes, since
19607 we don't have any arguments for them. Note that the standard
19608 is unclear on whether the instantiation of the members are
19609 *explicit* instantiations or not. However, the most natural
19610 interpretation is that it should be an explicit instantiation. */
19625 }
19626 }
19628 /* Given a function DECL, which is a specialization of TMPL, modify
19629 DECL to be a re-instantiation of TMPL with the same template
19630 arguments. TMPL should be the template into which tsubst'ing
19631 should occur for DECL, not the most general template.
19633 One reason for doing this is a scenario like this:
19635 template <class T>
19636 void f(const T&, int i);
19638 void g() { f(3, 7); }
19640 template <class T>
19641 void f(const T& t, const int i) { }
19643 Note that when the template is first instantiated, with
19644 instantiate_template, the resulting DECL will have no name for the
19645 first parameter, and the wrong type for the second. So, when we go
19646 to instantiate the DECL, we regenerate it. */
19648 static void
19650 {
19651 /* The arguments used to instantiate DECL, from the most general
19652 template. */
19653 tree args;
19654 tree code_pattern;
19659 /* Make sure that we can see identifiers, and compute access
19660 correctly. */
19664 {
19665 tree decl_parm;
19666 tree pattern_parm;
19667 tree specs;
19681 specs);
19683 /* Merge parameter declarations. */
19686 pattern_parm
19690 {
19691 tree parm_type;
19692 tree attributes;
19697 NULL_TREE);
19703 {
19706 }
19709 }
19710 /* Merge any parameters that match with the function parameter
19711 pack. */
19713 {
19715 tree expanded_types;
19716 /* Expand the TYPE_PACK_EXPANSION that provides the types for
19717 the parameters in this function parameter pack. */
19722 {
19723 tree parm_type;
19724 tree attributes;
19727 /* Rename the parameter to include the index. */
19736 {
19739 }
19741 }
19742 }
19743 /* Merge additional specifiers from the CODE_PATTERN. */
19747 }
19749 {
19757 }
19758 else
19762 }
19764 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
19765 substituted to get DECL. */
19767 tree
19769 {
19772 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
19773 for the instantiation. This is not always the most general
19774 template. Consider, for example:
19776 template <class T>
19777 struct S { template <class U> void f();
19778 template <> void f<int>(); };
19780 and an instantiation of S<double>::f<int>. We want TD to be the
19781 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
19783 more general template. */
19785 /* We must also deal with friend templates. Given:
19787 template <class T> struct S {
19788 template <class U> friend void f() {};
19789 };
19791 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
19792 so far as the language is concerned, but that's still
19793 where we get the pattern for the instantiation from. On
19794 other hand, if the definition comes outside the class, say:
19796 template <class T> struct S {
19797 template <class U> friend void f();
19798 };
19799 template <class U> friend void f() {}
19801 we don't need to look any further. That's what the check for
19802 DECL_INITIAL is for. */
19806 {
19807 /* The present template, TD, should not be a definition. If it
19808 were a definition, we should be using it! Note that we
19809 cannot restructure the loop to just keep going until we find
19810 a template with a definition, since that might go too far if
19811 a specialization was declared, but not defined. */
19813 /* Fetch the more general template. */
19815 }
19818 }
19820 /* Returns true if we need to instantiate this template instance even if we
19821 know we aren't going to emit it.. */
19823 bool
19825 {
19826 /* We always instantiate inline functions so that we can inline them. An
19827 explicit instantiation declaration prohibits implicit instantiation of
19828 non-inline functions. With high levels of optimization, we would
19829 normally inline non-inline functions -- but we're not allowed to do
19830 that for "extern template" functions. Therefore, we check
19831 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
19835 /* And we need to instantiate static data members so that
19836 their initializers are available in integral constant
19837 expressions. */
19840 }
19842 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
19843 instantiate it now, modifying TREE_TYPE (fn). */
19845 void
19847 {
19850 /* Don't instantiate a noexcept-specification from template context. */
19865 {
19869 {
19884 }
19885 else
19889 }
19892 {
19895 else
19897 }
19898 }
19900 /* Produce the definition of D, a _DECL generated from a template. If
19901 DEFER_OK is nonzero, then we don't have to actually do the
19902 instantiation now; we just have to do it sometime. Normally it is
19903 an error if this is an explicit instantiation but D is undefined.
19904 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
19905 explicitly instantiated class template. */
19907 tree
19910 {
19912 tree gen_args;
19913 tree args;
19914 tree td;
19915 tree code_pattern;
19916 tree spec;
19917 tree gen_tmpl;
19924 tree fn_context;
19927 /* This function should only be used to instantiate templates for
19928 functions and static member variables. */
19931 /* Variables are never deferred; if instantiation is required, they
19932 are instantiated right away. That allows for better code in the
19933 case that an expression refers to the value of the variable --
19934 if the variable has a constant value the referring expression can
19935 take advantage of that fact. */
19940 /* Don't instantiate cloned functions. Instead, instantiate the
19941 functions they cloned. */
19949 /* D has already been instantiated or explicitly specialized, so
19950 there's nothing for us to do here.
19952 It might seem reasonable to check whether or not D is an explicit
19953 instantiation, and, if so, stop here. But when an explicit
19954 instantiation is deferred until the end of the compilation,
19955 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
19956 the instantiation. */
19959 /* Check to see whether we know that this template will be
19960 instantiated in some other file, as with "extern template"
19961 extension. */
19964 /* In general, we do not instantiate such templates. */
19972 /* We should already have the extra args. */
19975 /* And what's in the hash table should match D. */
19979 /* This needs to happen before any tsubsting. */
19985 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
19986 for the instantiation. */
19990 /* We should never be trying to instantiate a member of a class
19991 template or partial specialization. */
19996 /* In the case of a friend template whose definition is provided
19997 outside the class, we may have too many arguments. Drop the
19998 ones we don't need. The same is true for specializations. */
19999 args = get_innermost_template_args
20001 else
20005 {
20010 }
20011 else
20012 {
20015 }
20017 /* We may be in the middle of deferred access check. Disable it now. */
20020 /* Unless an explicit instantiation directive has already determined
20021 the linkage of D, remember that a definition is available for
20022 this entity. */
20032 /* If D is a member of an explicitly instantiated class template,
20033 and no definition is available, treat it like an implicit
20034 instantiation. */
20037 {
20038 /* Leave linkage flags alone on instantiations with anonymous
20039 visibility. */
20041 {
20044 }
20046 }
20048 /* Defer all other templates, unless we have been explicitly
20049 forbidden from doing so. */
20051 template. */
20052 ! pattern_defined
20053 /* If it's OK to postpone instantiation, do so. */
20054 || defer_ok
20055 /* If this is a static data member that will be defined
20056 elsewhere, we don't want to instantiate the entire data
20057 member, but we do want to instantiate the initializer so that
20058 we can substitute that elsewhere. */
20060 /* Handle here a deleted function too, avoid generating
20061 its body (c++/61080). */
20063 {
20064 /* The definition of the static data member is now required so
20065 we must substitute the initializer. */
20069 {
20070 tree ns;
20071 tree init;
20080 args,
20083 /* If instantiating the initializer involved instantiating this
20084 again, don't call cp_finish_decl twice. */
20086 {
20087 /* Make sure the initializer is still constant, in case of
20088 circular dependency (template/instantiate6.C). */
20089 const_init
20093 LOOKUP_ONLYCONVERTING);
20094 }
20098 }
20100 /* We restore the source position here because it's used by
20101 add_pending_template. */
20107 /* [temp.explicit]
20109 The definition of a non-exported function template, a
20110 non-exported member function template, or a non-exported
20111 member function or static data member of a class template
20112 shall be present in every translation unit in which it is
20113 explicitly instantiated. */
20117 /* If we're in unevaluated context, we just wanted to get the
20118 constant value; this isn't an odr use, so don't queue
20119 a full instantiation. */
20122 /* ??? Historically, we have instantiated inline functions, even
20123 when marked as "extern template". */
20127 }
20128 /* Tell the repository that D is available in this translation unit
20129 -- and see if it is supposed to be instantiated here. */
20131 {
20132 /* In a PCH file, despite the fact that the repository hasn't
20133 requested instantiation in the PCH it is still possible that
20134 an instantiation will be required in a file that includes the
20135 PCH. */
20138 /* Instantiate inline functions so that the inliner can do its
20139 job, even though we'll not be emitting a copy of this
20140 function. */
20143 }
20149 else
20150 {
20155 }
20157 /* Mark D as instantiated so that recursive calls to
20158 instantiate_decl do not try to instantiate it again. */
20161 /* Regenerate the declaration in case the template has been modified
20162 by a subsequent redeclaration. */
20165 /* We already set the file and line above. Reset them now in case
20166 they changed as a result of calling regenerate_decl_from_template. */
20170 {
20171 tree init;
20174 /* Clear out DECL_RTL; whatever was there before may not be right
20175 since we've reset the type of the declaration. */
20179 /* The initializer is placed in DECL_INITIAL by
20180 regenerate_decl_from_template so we don't need to
20181 push/pop_access_scope again here. Pull it out so that
20182 cp_finish_decl can process it. */
20187 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
20188 initializer. That function will defer actual emission until
20189 we have a chance to determine linkage. */
20192 /* Enter the scope of D so that access-checking works correctly. */
20205 }
20209 {
20211 tree subst_decl;
20212 tree tmpl_parm;
20213 tree spec_parm;
20216 /* Save away the current list, in case we are instantiating one
20217 template from within the body of another. */
20220 /* Set up the list of local specializations. */
20223 /* Set up context. */
20227 else
20230 /* Some typedefs referenced from within the template code need to be
20231 access checked at template instantiation time, i.e now. These
20232 types were added to the template at parsing time. Let's get those
20233 and perform the access checks then. */
20235 gen_args);
20237 /* Create substitution entries for the parameters. */
20242 {
20246 }
20248 {
20250 {
20253 }
20254 else
20255 {
20256 /* Register the (value) argument pack as a specialization of
20257 TMPL_PARM, then move on. */
20260 }
20261 }
20264 /* Substitute into the body of the function. */
20268 else
20269 {
20274 /* Set the current input_location to the end of the function
20275 so that finish_function knows where we are. */
20276 input_location
20279 /* Remember if we saw an infinite loop in the template. */
20280 current_function_infinite_loop
20282 }
20284 /* We don't need the local specializations any more. */
20288 /* Finish the function. */
20292 else
20293 {
20296 }
20300 }
20302 /* We're not deferring instantiation any more. */
20310 out:
20320 }
20322 /* Run through the list of templates that we wish we could
20323 instantiate, and instantiate any we can. RETRIES is the
20324 number of times we retry pending template instantiation. */
20326 void
20328 {
20332 /* Instantiating templates may trigger vtable generation. This in turn
20333 may require further template instantiations. We place a limit here
20334 to avoid infinite loop. */
20336 {
20340 " instantiating %q+D, possibly from virtual table generation"
20344 /* Pretend that we defined it. */
20347 }
20349 do
20350 {
20355 {
20360 {
20361 tree fn;
20364 {
20368 fn;
20376 }
20379 }
20380 else
20381 {
20384 {
20385 instantiation
20391 }
20395 }
20398 /* If INSTANTIATION has been instantiated, then we don't
20399 need to consider it again in the future. */
20401 else
20402 {
20405 }
20408 }
20410 }
20414 }
20416 /* Substitute ARGVEC into T, which is a list of initializers for
20417 either base class or a non-static data member. The TREE_PURPOSEs
20418 are DECLs, and the TREE_VALUEs are the initializer values. Used by
20419 instantiate_decl. */
20421 static tree
20423 {
20427 {
20428 tree decl;
20429 tree init;
20435 {
20436 tree expr;
20437 tree arg;
20439 /* Expand the base class expansion type into separate base
20440 classes. */
20442 tf_warning_or_error,
20443 NULL_TREE);
20447 /* We'll be building separate TREE_LISTs of arguments for
20448 each base. */
20454 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
20455 expand each argument in the TREE_VALUE of t. */
20462 /* VOID_TYPE_NODE is used to indicate
20463 value-initialization. */
20464 {
20467 }
20468 else
20469 {
20470 /* Substitute parameter packs into each argument in the
20471 TREE_LIST. */
20474 {
20475 tree expanded_exprs;
20477 /* Expand the argument. */
20479 expanded_exprs
20481 tf_warning_or_error,
20482 NULL_TREE);
20486 /* Prepend each of the expanded expressions to the
20487 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
20489 {
20494 }
20495 }
20498 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
20499 since we built them backwards. */
20501 {
20504 }
20505 }
20506 }
20509 {
20511 {
20515 }
20516 else
20517 {
20518 tree tmp;
20533 /* If we had an initializer but it instantiated to nothing,
20534 value-initialize the object. This will only occur when
20535 the initializer was a pack expansion where the parameter
20536 packs used in that expansion were of length zero. */
20539 }
20542 {
20546 }
20547 }
20548 }
20550 }
20552 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
20554 static void
20556 {
20561 else
20563 }
20565 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
20566 is the instantiation (which should have been created with
20567 start_enum) and ARGS are the template arguments to use. */
20569 static void
20571 {
20572 tree e;
20578 {
20579 tree value;
20580 tree decl;
20583 /* Note that in a template enum, the TREE_VALUE is the
20584 CONST_DECL, not the corresponding INTEGER_CST. */
20589 /* Give this enumeration constant the correct access. */
20592 /* Actually build the enumerator itself. */
20593 build_enumerator
20595 }
20605 }
20607 /* DECL is a FUNCTION_DECL that is a template specialization. Return
20608 its type -- but without substituting the innermost set of template
20609 arguments. So, innermost set of template parameters will appear in
20610 the type. */
20612 tree
20614 {
20615 tree fn_type;
20616 tree tmpl;
20617 tree targs;
20618 tree tparms;
20626 /* There should be as many levels of arguments as there are levels
20627 of parameters. */
20633 /* No substitution is necessary. */
20634 ;
20635 else
20636 {
20638 tree partial_args;
20640 /* Replace the innermost level of the TARGS with NULL_TREEs to
20641 let tsubst know not to substitute for those parameters. */
20650 /* Make sure that we can see identifiers, and compute access
20651 correctly. */
20655 /* Now, do the (partial) substitution to figure out the
20656 appropriate function type. */
20660 /* Substitute into the template parameters to obtain the real
20661 innermost set of parameters. This step is important if the
20662 innermost set of template parameters contains value
20663 parameters whose types depend on outer template parameters. */
20668 }
20671 }
20673 /* Return truthvalue if we're processing a template different from
20674 the last one involved in diagnostics. */
20675 bool
20677 {
20679 }
20681 /* Remember current template involved in diagnostics. */
20682 void
20684 {
20686 }
20690 {
20692 }
20694 /* [temp.param] Check that template non-type parm TYPE is of an allowable
20695 type. Return zero for ok, nonzero for disallowed. Issue error and
20696 warning messages under control of COMPLAIN. */
20698 static int
20700 {
20717 {
20720 else
20722 type);
20723 }
20725 }
20727 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
20728 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
20730 static bool
20732 {
20733 tree scope;
20735 /* [temp.dep.type]
20737 A type is dependent if it is:
20739 -- a template parameter. Template template parameters are types
20740 for us (since TYPE_P holds true for them) so we handle
20741 them here. */
20745 /* -- a qualified-id with a nested-name-specifier which contains a
20746 class-name that names a dependent type or whose unqualified-id
20747 names a dependent type. */
20750 /* -- a cv-qualified type where the cv-unqualified type is
20751 dependent.
20752 No code is necessary for this bullet; the code below handles
20753 cv-qualified types, and we don't want to strip aliases with
20754 TYPE_MAIN_VARIANT because of DR 1558. */
20755 /* -- a compound type constructed from any dependent type. */
20765 {
20766 tree arg_type;
20771 arg_type;
20776 }
20777 /* -- an array type constructed from any dependent type or whose
20778 size is specified by a constant expression that is
20779 value-dependent.
20781 We checked for type- and value-dependence of the bounds in
20782 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
20784 {
20789 }
20791 /* -- a template-id in which either the template name is a template
20792 parameter ... */
20795 /* ... or any of the template arguments is a dependent type or
20796 an expression that is type-dependent or value-dependent. */
20798 && (any_dependent_template_arguments_p
20802 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
20803 dependent; if the argument of the `typeof' expression is not
20804 type-dependent, then it should already been have resolved. */
20810 /* A template argument pack is dependent if any of its packed
20811 arguments are. */
20813 {
20819 }
20821 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
20822 be template parameters. */
20826 /* The standard does not specifically mention types that are local
20827 to template functions or local classes, but they should be
20828 considered dependent too. For example:
20830 template <int I> void f() {
20831 enum E { a = I };
20832 S<sizeof (E)> s;
20833 }
20835 The size of `E' cannot be known until the value of `I' has been
20836 determined. Therefore, `E' must be considered dependent. */
20840 /* Don't use type_dependent_expression_p here, as it can lead
20841 to infinite recursion trying to determine whether a lambda
20842 nested in a lambda is dependent (c++/47687). */
20846 && (any_dependent_template_arguments_p
20850 /* Other types are non-dependent. */
20852 }
20854 /* Returns TRUE if TYPE is dependent, in the sense of
20855 [temp.dep.type]. Note that a NULL type is considered dependent. */
20857 bool
20859 {
20860 /* If there are no template parameters in scope, then there can't be
20861 any dependent types. */
20863 {
20864 /* If we are not processing a template, then nobody should be
20865 providing us with a dependent type. */
20869 }
20871 /* If the type is NULL, we have not computed a type for the entity
20872 in question; in that case, the type is dependent. */
20876 /* Erroneous types can be considered non-dependent. */
20880 /* If we have not already computed the appropriate value for TYPE,
20881 do so now. */
20883 {
20886 }
20889 }
20891 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
20892 lookup. In other words, a dependent type that is not the current
20893 instantiation. */
20895 bool
20897 {
20900 }
20902 /* T is a SCOPE_REF; return whether we need to consider it
20903 instantiation-dependent so that we can check access at instantiation
20904 time even though we know which member it resolves to. */
20906 static bool
20908 {
20914 else
20916 }
20918 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
20919 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
20920 expression. */
20922 /* Note that this predicate is not appropriate for general expressions;
20923 only constant expressions (that satisfy potential_constant_expression)
20924 can be tested for value dependence. */
20926 bool
20928 {
20932 /* A name declared with a dependent type. */
20937 {
20939 /* A name that has not been looked up -- must be dependent. */
20943 /* A non-type template parm. */
20947 /* A non-type template parm. */
20953 /* A constant with literal type and is initialized
20954 with an expression that is value-dependent.
20956 Note that a non-dependent parenthesized initializer will have
20957 already been replaced with its constant value, so if we see
20958 a TREE_LIST it must be dependent. */
20962 /* cp_finish_decl doesn't fold reference initializers. */
20973 /* These expressions are value-dependent if the type to which
20974 the cast occurs is dependent or the expression being casted
20975 is value-dependent. */
20976 {
20982 /* A functional cast has a list of operands. */
20985 {
20986 /* If there are no operands, it must be an expression such
20987 as "int()". This should not happen for aggregate types
20988 because it would form non-constant expressions. */
20993 }
20999 }
21004 /* FALLTHRU */
21007 /* A `sizeof' expression is value-dependent if the operand is
21008 type-dependent or is a pack expansion. */
21017 /* An 'encode' expression is value-dependent if the operand is
21018 type-dependent. */
21027 /* All instantiation-dependent expressions should also be considered
21028 value-dependent. */
21036 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
21037 is value-dependent. */
21038 {
21047 }
21050 {
21054 }
21065 {
21069 }
21072 {
21079 {
21081 /* In a call to a constexpr member function, look through the
21082 implicit ADDR_EXPR on the object argument so that it doesn't
21083 cause the call to be considered value-dependent. We also
21084 look through it in potential_constant_expression. */
21091 }
21093 }
21096 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
21097 type-dependent. */
21101 {
21103 tree val;
21110 }
21113 /* Treat a GNU statement expression as dependent to avoid crashing
21114 under instantiate_non_dependent_expr; it can't be constant. */
21118 /* A constant expression is value-dependent if any subexpression is
21119 value-dependent. */
21121 {
21128 {
21132 {
21135 /* In some cases, some of the operands may be missing.l
21136 (For example, in the case of PREDECREMENT_EXPR, the
21137 amount to increment by may be missing.) That doesn't
21138 make the expression dependent. */
21141 }
21142 }
21146 }
21148 }
21150 /* The expression is not value-dependent. */
21152 }
21154 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
21155 [temp.dep.expr]. Note that an expression with no type is
21156 considered dependent. Other parts of the compiler arrange for an
21157 expression with type-dependent subexpressions to have no type, so
21158 this function doesn't have to be fully recursive. */
21160 bool
21162 {
21169 /* An unresolved name is always dependent. */
21173 /* Some expression forms are never type-dependent. */
21186 /* The types of these expressions depends only on the type to which
21187 the cast occurs. */
21196 /* The types of these expressions depends only on the type created
21197 by the expression. */
21200 {
21201 /* For NEW_EXPR tree nodes created inside a template, either
21202 the object type itself or a TREE_LIST may appear as the
21203 operand 1. */
21206 /* This is an array type. We need to check array dimensions
21207 as well. */
21209 || value_dependent_expression_p
21211 else
21213 }
21216 {
21220 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
21221 contains an identifier associated by name lookup with one or more
21222 declarations declared with a dependent type, or...a
21223 nested-name-specifier or qualified-id that names a member of an
21224 unknown specialization. */
21227 }
21232 && (any_dependent_template_arguments_p
21244 {
21245 tree elt;
21249 {
21252 }
21254 }
21256 /* A static data member of the current instantiation with incomplete
21257 array type is type-dependent, as the definition and specializations
21258 can have different bounds. */
21265 /* An array of unknown bound depending on a variadic parameter, eg:
21267 template<typename... Args>
21268 void foo (Args... args)
21269 {
21270 int arr[] = { args... };
21271 }
21273 template<int... vals>
21274 void bar ()
21275 {
21276 int arr[] = { vals... };
21277 }
21279 If the array has no length and has an initializer, it must be that
21280 we couldn't determine its length in cp_complete_array_type because
21281 it is dependent. */
21289 {
21294 {
21300 }
21301 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
21305 /* Always dependent, on the number of arguments if nothing else. */
21310 {
21315 }
21318 {
21323 }
21328 {
21332 }
21334 }
21339 }
21341 /* walk_tree callback function for instantiation_dependent_expression_p,
21342 below. Returns non-zero if a dependent subexpression is found. */
21344 static tree
21347 {
21349 {
21350 /* We don't have to worry about decltype currently because decltype
21351 of an instantiation-dependent expr is a dependent type. This
21352 might change depending on the resolution of DR 1172. */
21355 }
21358 {
21359 /* Don't treat an argument list as dependent just because it has no
21360 TREE_TYPE. */
21367 /* A constant with a dependent initializer is dependent. */
21375 /* Handle expressions with type operands. */
21380 {
21385 {
21388 else
21389 {
21392 }
21393 }
21395 }
21407 /* In a template, finish_class_member_access_expr creates a
21408 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
21409 type-dependent, so that we can check access control at
21410 instantiation time (PR 42277). See also Core issue 1273. */
21417 else
21420 /* Treat statement-expressions as dependent. */
21426 }
21430 else
21432 }
21434 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
21435 sense defined by the ABI:
21437 "An expression is instantiation-dependent if it is type-dependent
21438 or value-dependent, or it has a subexpression that is type-dependent
21439 or value-dependent." */
21441 bool
21443 {
21444 tree result;
21455 }
21457 /* Like type_dependent_expression_p, but it also works while not processing
21458 a template definition, i.e. during substitution or mangling. */
21460 bool
21462 {
21468 }
21470 /* Returns TRUE if ARGS contains a type-dependent expression. */
21472 bool
21474 {
21476 tree arg;
21479 {
21482 }
21484 }
21486 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
21487 expressions) contains any type-dependent expressions. */
21489 bool
21491 {
21497 }
21499 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
21500 expressions) contains any value-dependent expressions. */
21502 bool
21504 {
21510 }
21512 /* Returns TRUE if the ARG (a template argument) is dependent. */
21514 bool
21516 {
21520 /* Assume a template argument that was wrongly written by the user
21521 is dependent. This is consistent with what
21522 any_dependent_template_arguments_p [that calls this function]
21523 does. */
21534 {
21538 {
21541 }
21544 }
21547 else
21550 }
21552 /* Returns true if ARGS (a collection of template arguments) contains
21553 any types that require structural equality testing. */
21555 bool
21557 {
21567 {
21570 {
21576 {
21577 /* Look inside the argument pack. */
21580 }
21583 {
21596 }
21597 }
21598 }
21601 }
21603 /* Returns true if ARGS (a collection of template arguments) contains
21604 any dependent arguments. */
21606 bool
21608 {
21618 {
21623 }
21626 }
21628 /* Returns TRUE if the template TMPL is dependent. */
21630 bool
21632 {
21634 {
21636 {
21640 }
21642 }
21644 /* Template template parameters are dependent. */
21648 /* So are names that have not been looked up. */
21651 /* So are member templates of dependent classes. */
21655 }
21657 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
21659 bool
21661 {
21664 }
21666 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
21667 is dependent. */
21669 bool
21671 {
21678 {
21699 {
21703 }
21707 {
21711 {
21716 }
21717 }
21718 }
21721 }
21723 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
21724 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
21725 no such TYPE can be found. Note that this function peers inside
21726 uninstantiated templates and therefore should be used only in
21727 extremely limited situations. ONLY_CURRENT_P restricts this
21728 peering to the currently open classes hierarchy (which is required
21729 when comparing types). */
21731 tree
21733 {
21734 tree scope;
21735 tree name;
21736 tree decl;
21738 tree pushed_scope;
21739 tree result;
21744 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
21745 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
21746 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
21747 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
21748 identifier of the TYPENAME_TYPE anymore.
21749 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
21750 TYPENAME_TYPE instead, we avoid messing up with a possible
21751 typedef variant case. */
21754 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
21755 it first before we can figure out what NAME refers to. */
21757 {
21759 /* Given a class template A with a dependent base with nested type C,
21760 typedef typename A::C::C C will land us here, as trying to resolve
21761 the initial A::C leads to the local C typedef, which leads back to
21762 A::C::C. So we break the recursion now. */
21764 else
21766 }
21767 /* If we don't know what SCOPE refers to, then we cannot resolve the
21768 TYPENAME_TYPE. */
21771 /* If the SCOPE is a template type parameter, we have no way of
21772 resolving the name. */
21775 /* If the SCOPE is not the current instantiation, there's no reason
21776 to look inside it. */
21779 /* If this is a typedef, we don't want to look inside (c++/11987). */
21782 /* If SCOPE isn't the template itself, it will not have a valid
21783 TYPE_FIELDS list. */
21785 /* scope is either the template itself or a compatible instantiation
21786 like X<T>, so look up the name in the original template. */
21788 else
21789 /* scope is a partial instantiation, so we can't do the lookup or we
21790 will lose the template arguments. */
21792 /* Enter the SCOPE so that name lookup will be resolved as if we
21793 were in the class definition. In particular, SCOPE will no
21794 longer be considered a dependent type. */
21796 /* Look up the declaration. */
21798 tf_warning_or_error);
21802 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
21803 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
21808 {
21812 }
21815 {
21816 tree tmpl;
21817 tree args;
21818 /* Obtain the template and the arguments. */
21821 /* Instantiate the template. */
21827 }
21829 /* Leave the SCOPE. */
21833 /* If we failed to resolve it, return the original typename. */
21837 /* If lookup found a typename type, resolve that too. */
21839 {
21840 /* Ill-formed programs can cause infinite recursion here, so we
21841 must catch that. */
21845 }
21847 /* Qualify the resulting type. */
21853 }
21855 /* EXPR is an expression which is not type-dependent. Return a proxy
21856 for EXPR that can be used to compute the types of larger
21857 expressions containing EXPR. */
21859 tree
21861 {
21862 tree inner_expr;
21864 #ifdef ENABLE_CHECKING
21865 /* Try to get a constant value for all non-dependent expressions in
21866 order to expose bugs in *_dependent_expression_p and constexpr. */
21869 #endif
21871 /* Preserve OVERLOADs; the functions must be available to resolve
21872 types. */
21883 /* There is no need to return a proxy for a variable. */
21886 /* Preserve string constants; conversions from string constants to
21887 "char *" are allowed, even though normally a "const char *"
21888 cannot be used to initialize a "char *". */
21891 /* Preserve void and arithmetic constants, as an optimization -- there is no
21892 reason to create a new node. */
21897 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
21898 There is at least one place where we want to know that a
21899 particular expression is a throw-expression: when checking a ?:
21900 expression, there are special rules if the second or third
21901 argument is a throw-expression. */
21905 /* Don't wrap an initializer list, we need to be able to look inside. */
21909 /* Don't wrap a dummy object, we need to be able to test for it. */
21928 /* If the type is unknown, it can't really be non-dependent */
21931 /* Otherwise, build a NON_DEPENDENT_EXPR. */
21933 }
21935 /* ARGS is a vector of expressions as arguments to a function call.
21936 Replace the arguments with equivalent non-dependent expressions.
21937 This modifies ARGS in place. */
21939 void
21941 {
21943 tree arg;
21946 {
21950 }
21951 }
21953 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
21954 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
21955 parms. */
21957 static tree
21959 {
21972 }
21974 tree
21976 {
21978 }
21980 tree
21982 {
21984 }
21986 /* Given type ARG, return std::initializer_list<ARG>. */
21988 static tree
21990 {
21991 tree std_init_list = namespace_binding
21993 tree argvec;
21995 {
21999 }
22004 }
22006 /* Replace auto in TYPE with std::initializer_list<auto>. */
22008 static tree
22010 {
22017 }
22019 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
22020 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
22022 tree
22024 {
22025 tree targs;
22031 /* Defining a subset of type-dependent expressions that we can deduce
22032 from ahead of time isn't worth the trouble. */
22035 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
22036 with either a new invented type template parameter U or, if the
22037 initializer is a braced-init-list (8.5.4), with
22038 std::initializer_list<U>. */
22046 {
22052 {
22055 }
22056 }
22057 else
22058 {
22069 {
22071 /* Try again at instantiation time. */
22074 /* If type is error_mark_node a diagnostic must have been
22075 emitted by now. Also, having a mention to '<type error>'
22076 in the diagnostic is not really useful to the user. */
22077 {
22081 else
22083 }
22085 }
22086 }
22088 /* If the list of declarators contains more than one declarator, the type
22089 of each declared variable is determined as described above. If the
22090 type deduced for the template parameter U is not the same in each
22091 deduction, the program is ill-formed. */
22094 {
22100 else
22104 }
22110 }
22112 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
22113 result. */
22115 tree
22117 {
22118 tree argvec;
22125 /* For a late-specified return type in a template type-parameter, we
22126 need to add a dummy argument level for its parmlist. */
22127 argvec = add_to_template_args
22132 }
22134 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
22135 'decltype(auto)'. */
22137 bool
22139 {
22144 else
22146 }
22148 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
22149 a use of `auto'. Returns NULL_TREE otherwise. */
22151 tree
22153 {
22155 }
22157 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto',
22158 'decltype(auto)' or a concept. */
22160 bool
22162 {
22164 }
22166 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing a generic type (`auto' or
22167 a concept identifier) iff TYPE contains a use of a generic type. Returns
22168 NULL_TREE otherwise. */
22170 tree
22172 {
22174 }
22177 /* For a given template T, return the vector of typedefs referenced
22178 in T for which access check is needed at T instantiation time.
22179 T is either a FUNCTION_DECL or a RECORD_TYPE.
22180 Those typedefs were added to T by the function
22181 append_type_to_template_for_access_check. */
22185 {
22186 tree ti;
22197 {
22202 }
22205 }
22207 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
22208 tied to T. That list of typedefs will be access checked at
22209 T instantiation time.
22210 T is either a FUNCTION_DECL or a RECORD_TYPE.
22211 TYPE_DECL is a TYPE_DECL node representing a typedef.
22212 SCOPE is the scope through which TYPE_DECL is accessed.
22213 LOCATION is the location of the usage point of TYPE_DECL.
22215 This function is a subroutine of
22216 append_type_to_template_for_access_check. */
22218 static void
22220 tree type_decl,
22221 tree scope,
22222 location_t location)
22223 {
22224 qualified_typedef_usage_t typedef_usage;
22225 tree ti;
22232 && type_decl
22246 }
22248 /* Append TYPE_DECL to the template TEMPL.
22249 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
22250 At TEMPL instanciation time, TYPE_DECL will be checked to see
22251 if it can be accessed through SCOPE.
22252 LOCATION is the location of the usage point of TYPE_DECL.
22254 e.g. consider the following code snippet:
22256 class C
22257 {
22258 typedef int myint;
22259 };
22261 template<class U> struct S
22262 {
22263 C::myint mi; // <-- usage point of the typedef C::myint
22264 };
22266 S<char> s;
22268 At S<char> instantiation time, we need to check the access of C::myint
22269 In other words, we need to check the access of the myint typedef through
22270 the C scope. For that purpose, this function will add the myint typedef
22271 and the scope C through which its being accessed to a list of typedefs
22272 tied to the template S. That list will be walked at template instantiation
22273 time and access check performed on each typedefs it contains.
22274 Note that this particular code snippet should yield an error because
22275 myint is private to C. */
22277 void
22279 tree type_decl,
22280 tree scope,
22281 location_t location)
22282 {
22288 /* Make sure we don't append the type to the template twice. */
22295 }
22297 /* Convert the generic type parameters in PARM that match the types given in the
22298 range [START_IDX, END_IDX) from the current_template_parms into generic type
22299 packs. */
22301 tree
22303 {
22314 {
22315 /* Create a distinct parameter pack type from the current parm and add it
22316 to the replacement args to tsubst below into the generic function
22317 parameter. */
22332 }
22338 /* If there are more levels then build up the replacement with the outer
22339 template parms. */
22343 replacement);
22346 }
22349 /* Set up the hash tables for template instantiations. */
22351 void
22353 {
22356 }
22358 /* Print stats about the template hash tables for -fstats. */
22360 void
22362 {
22371 }