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1 /* Handle parameterized types (templates) for GNU C++.
2 Copyright (C) 1992-2013 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
45 /* The type of functions taking a tree, and some additional data, and
46 returning an int. */
49 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
50 instantiations have been deferred, either because their definitions
51 were not yet available, or because we were putting off doing the work. */
55 };
70 /* Live only within one (recursive) call to tsubst_expr. We use
71 this to pass the statement expression node from the STMT_EXPR
72 to the EXPR_STMT that is its result. */
75 /* A map from local variable declarations in the body of the template
76 presently being instantiated to the corresponding instantiated
77 local variables. */
80 /* True if we've recursed into fn_type_unification too many times. */
84 {
85 tree tmpl;
86 tree args;
87 tree spec;
91 htab_t decl_specializations;
94 htab_t type_specializations;
96 /* Contains canonical template parameter types. The vector is indexed by
97 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
98 TREE_LIST, whose TREE_VALUEs contain the canonical template
99 parameters of various types and levels. */
102 #define UNIFY_ALLOW_NONE 0
103 #define UNIFY_ALLOW_MORE_CV_QUAL 1
104 #define UNIFY_ALLOW_LESS_CV_QUAL 2
105 #define UNIFY_ALLOW_DERIVED 4
106 #define UNIFY_ALLOW_INTEGER 8
107 #define UNIFY_ALLOW_OUTER_LEVEL 16
108 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
109 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
112 tbr_incomplete_type,
113 tbr_ambiguous_baseclass,
114 tbr_success
115 };
138 tree);
201 location_t);
209 /* Make the current scope suitable for access checking when we are
210 processing T. T can be FUNCTION_DECL for instantiated function
211 template, VAR_DECL for static member variable, or TYPE_DECL for
212 alias template (needed by instantiate_decl). */
214 static void
216 {
225 else
229 {
230 saved_access_scope = tree_cons
233 }
234 }
236 /* Restore the scope set up by push_access_scope. T is the node we
237 are processing. */
239 static void
241 {
243 {
246 }
250 else
252 }
254 /* Do any processing required when DECL (a member template
255 declaration) is finished. Returns the TEMPLATE_DECL corresponding
256 to DECL, unless it is a specialization, in which case the DECL
257 itself is returned. */
259 tree
261 {
268 {
269 tree type;
277 {
281 }
283 }
287 {
289 {
292 }
293 else
295 }
296 else
300 }
302 /* Create a template info node. */
304 tree
306 {
311 }
313 /* Return the template info node corresponding to T, whatever T is. */
315 tree
317 {
335 }
337 /* Returns the template nesting level of the indicated class TYPE.
339 For example, in:
340 template <class T>
341 struct A
342 {
343 template <class U>
344 struct B {};
345 };
347 A<T>::B<U> has depth two, while A<T> has depth one.
348 Both A<T>::B<int> and A<int>::B<U> have depth one, if
349 they are instantiations, not specializations.
351 This function is guaranteed to return 0 if passed NULL_TREE so
352 that, for example, `template_class_depth (current_class_type)' is
353 always safe. */
355 int
357 {
364 {
370 }
373 }
375 /* Subroutine of maybe_begin_member_template_processing.
376 Returns true if processing DECL needs us to push template parms. */
378 static bool
380 {
386 }
388 /* Subroutine of maybe_begin_member_template_processing.
389 Push the template parms in PARMS, starting from LEVELS steps into the
390 chain, and ending at the beginning, since template parms are listed
391 innermost first. */
393 static void
395 {
403 current_template_parms
409 NULL);
411 {
420 {
427 {
428 /* Make a CONST_DECL as is done in process_template_parm.
429 It is ugly that we recreate this here; the original
430 version built in process_template_parm is no longer
431 available. */
441 }
446 }
447 }
448 }
450 /* Restore the template parameter context for a member template or
451 a friend template defined in a class definition. */
453 void
455 {
456 tree parms;
460 {
465 {
468 }
471 }
473 /* Remember how many levels of template parameters we pushed so that
474 we can pop them later. */
476 }
478 /* Undo the effects of maybe_begin_member_template_processing. */
480 void
482 {
491 {
495 }
496 }
498 /* Return a new template argument vector which contains all of ARGS,
499 but has as its innermost set of arguments the EXTRA_ARGS. */
501 static tree
503 {
504 tree new_args;
522 }
524 /* Like add_to_template_args, but only the outermost ARGS are added to
525 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
526 (EXTRA_ARGS) levels are added. This function is used to combine
527 the template arguments from a partial instantiation with the
528 template arguments used to attain the full instantiation from the
529 partial instantiation. */
531 static tree
533 {
534 tree new_args;
536 /* If there are more levels of EXTRA_ARGS than there are ARGS,
537 something very fishy is going on. */
540 /* If *all* the new arguments will be the EXTRA_ARGS, just return
541 them. */
545 /* For the moment, we make ARGS look like it contains fewer levels. */
550 /* Now, we restore ARGS to its full dimensions. */
554 }
556 /* Return the N levels of innermost template arguments from the ARGS. */
558 tree
560 {
561 tree new_args;
567 /* If N is 1, just return the innermost set of template arguments. */
571 /* If we're not removing anything, just return the arguments we were
572 given. */
578 /* Make a new set of arguments, not containing the outer arguments. */
585 }
587 /* The inverse of get_innermost_template_args: Return all but the innermost
588 EXTRA_LEVELS levels of template arguments from the ARGS. */
590 static tree
592 {
593 tree new_args;
599 /* If N is 1, just return the outermost set of template arguments. */
603 /* If we're not removing anything, just return the arguments we were
604 given. */
609 /* Make a new set of arguments, not containing the inner arguments. */
616 }
618 /* We've got a template header coming up; push to a new level for storing
619 the parms. */
621 void
623 {
624 /* We use a non-tag-transparent scope here, which causes pushtag to
625 put tags in this scope, rather than in the enclosing class or
626 namespace scope. This is the right thing, since we want
627 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
628 global template class, push_template_decl handles putting the
629 TEMPLATE_DECL into top-level scope. For a nested template class,
630 e.g.:
632 template <class T> struct S1 {
633 template <class T> struct S2 {};
634 };
636 pushtag contains special code to call pushdecl_with_scope on the
637 TEMPLATE_DECL for S2. */
642 }
644 /* This routine is called when a specialization is declared. If it is
645 invalid to declare a specialization here, an error is reported and
646 false is returned, otherwise this routine will return true. */
648 static bool
650 {
653 /* [temp.expl.spec]
655 An explicit specialization shall be declared in the namespace of
656 which the template is a member, or, for member templates, in the
657 namespace of which the enclosing class or enclosing class
658 template is a member. An explicit specialization of a member
659 function, member class or static data member of a class template
660 shall be declared in the namespace of which the class template
661 is a member. */
663 {
666 }
668 /* [temp.expl.spec]
670 In an explicit specialization declaration for a member of a class
671 template or a member template that appears in namespace scope,
672 the member template and some of its enclosing class templates may
673 remain unspecialized, except that the declaration shall not
674 explicitly specialize a class member template if its enclosing
675 class templates are not explicitly specialized as well. */
677 {
680 }
683 }
685 /* We've just seen template <>. */
687 bool
689 {
693 }
695 /* Called at then end of processing a declaration preceded by
696 template<>. */
698 void
700 {
703 }
705 /* Any template <>'s that we have seen thus far are not referring to a
706 function specialization. */
708 void
710 {
713 }
715 /* We've just seen a template header. If SPECIALIZATION is nonzero,
716 it was of the form template <>. */
718 static void
720 {
722 template_header_count++;
723 }
725 /* We're beginning an explicit instantiation. */
727 void
729 {
732 }
735 void
737 {
740 }
742 /* An explicit specialization or partial specialization of TMPL is being
743 declared. Check that the namespace in which the specialization is
744 occurring is permissible. Returns false iff it is invalid to
745 specialize TMPL in the current namespace. */
747 static bool
749 {
752 /* [tmpl.expl.spec]
754 An explicit specialization shall be declared in the namespace of
755 which the template is a member, or, for member templates, in the
756 namespace of which the enclosing class or enclosing class
757 template is a member. An explicit specialization of a member
758 function, member class or static data member of a class template
759 shall be declared in the namespace of which the class template is
760 a member. */
763 {
766 }
768 /* Same or super-using namespace. */
770 else
771 {
775 }
776 }
778 /* SPEC is an explicit instantiation. Check that it is valid to
779 perform this explicit instantiation in the current namespace. */
781 static void
783 {
784 tree ns;
786 /* DR 275: An explicit instantiation shall appear in an enclosing
787 namespace of its template. */
793 }
795 /* The TYPE is being declared. If it is a template type, that means it
796 is a partial specialization. Do appropriate error-checking. */
798 tree
800 {
801 tree context;
806 /* A lambda that appears in specialization context is not itself a
807 specialization. */
812 {
816 }
821 {
826 else
829 }
831 {
832 /* This is for ordinary explicit specialization and partial
833 specialization of a template class such as:
835 template <> class C<int>;
837 or:
839 template <class T> class C<T*>;
841 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
845 {
850 {
854 }
855 }
861 /* Trying to define a specialization either without a template<> header
862 or in an inappropriate place. We've already given an error, so just
863 bail now so we don't actually define the specialization. */
865 }
871 {
872 /* This is for an explicit specialization of member class
873 template according to [temp.expl.spec/18]:
875 template <> template <class U> class C<int>::D;
877 The context `C<int>' must be an implicit instantiation.
878 Otherwise this is just a member class template declared
879 earlier like:
881 template <> class C<int> { template <class U> class D; };
882 template <> template <class U> class C<int>::D;
884 In the first case, `C<int>::D' is a specialization of `C<T>::D'
885 while in the second case, `C<int>::D' is a primary template
886 and `C<T>::D' may not exist. */
890 {
891 tree t;
896 {
899 }
901 /* Check for invalid specialization after instantiation:
903 template <> template <> class C<int>::D<int>;
904 template <> template <class U> class C<int>::D; */
908 {
911 {
912 /* We already have a full specialization of this partial
913 instantiation. Reassign it to the new member
914 specialization template. */
915 spec_entry elt;
932 }
934 /* But if we've had an implicit instantiation, that's a
935 problem ([temp.expl.spec]/6). */
938 }
940 /* Mark TYPE as a specialization. And as a result, we only
941 have one level of template argument for the innermost
942 class template. */
947 }
948 }
950 {
951 /* Someday C++0x may allow for enum template specialization. */
956 else
957 {
960 }
961 }
964 }
966 /* Returns nonzero if we can optimize the retrieval of specializations
967 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
968 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
972 {
975 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
976 parameter. */
978 /* The optimized lookup depends on the fact that the
979 template arguments for the member function template apply
980 purely to the containing class, which is not true if the
981 containing class is an explicit or partial
982 specialization. */
986 /* It is possible to have a template that is not a member
987 template and is not a member of a template class:
989 template <typename T>
990 struct S { friend A::f(); };
992 Here, the friend function is a template, but the context does
993 not have template information. The optimized lookup relies
994 on having ARGS be the template arguments for both the class
995 and the function template. */
997 }
999 /* Retrieve the specialization (in the sense of [temp.spec] - a
1000 specialization is either an instantiation or an explicit
1001 specialization) of TMPL for the given template ARGS. If there is
1002 no such specialization, return NULL_TREE. The ARGS are a vector of
1003 arguments, or a vector of vectors of arguments, in the case of
1004 templates with more than one level of parameters.
1006 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1007 then we search for a partial specialization matching ARGS. This
1008 parameter is ignored if TMPL is not a class template. */
1010 static tree
1012 {
1018 /* There should be as many levels of arguments as there are
1019 levels of parameters. */
1024 {
1025 tree class_template;
1026 tree class_specialization;
1028 tree fns;
1031 /* The template arguments actually apply to the containing
1032 class. Find the class specialization with those
1033 arguments. */
1035 class_specialization
1039 /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC
1040 for the specialization. */
1044 /* Iterate through the methods with the indicated name, looking
1045 for the one that has an instance of TMPL. */
1048 {
1051 /* using-declarations can add base methods to the method vec,
1052 and we don't want those here. */
1055 }
1057 }
1058 else
1059 {
1061 spec_entry elt;
1062 htab_t specializations;
1070 else
1078 }
1081 }
1083 /* Like retrieve_specialization, but for local declarations. */
1085 static tree
1087 {
1095 }
1097 /* Returns nonzero iff DECL is a specialization of TMPL. */
1099 int
1101 {
1102 tree t;
1105 {
1111 }
1112 else
1113 {
1122 }
1125 }
1127 /* Returns nonzero iff DECL is a specialization of friend declaration
1128 FRIEND_DECL according to [temp.friend]. */
1130 bool
1132 {
1139 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1140 of a template class, we want to check if DECL is a specialization
1141 if this. */
1145 {
1146 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1149 }
1154 /* There is nothing to do if this is not a template friend. */
1161 /* [temp.friend/6]
1162 A member of a class template may be declared to be a friend of a
1163 non-template class. In this case, the corresponding member of
1164 every specialization of the class template is a friend of the
1165 class granting friendship.
1167 For example, given a template friend declaration
1169 template <class T> friend void A<T>::f();
1171 the member function below is considered a friend
1173 template <> struct A<int> {
1174 void f();
1175 };
1177 For this type of template friend, TEMPLATE_DEPTH below will be
1178 nonzero. To determine if DECL is a friend of FRIEND, we first
1179 check if the enclosing class is a specialization of another. */
1186 {
1187 /* Next, we check the members themselves. In order to handle
1188 a few tricky cases, such as when FRIEND_DECL's are
1190 template <class T> friend void A<T>::g(T t);
1191 template <class T> template <T t> friend void A<T>::h();
1193 and DECL's are
1195 void A<int>::g(int);
1196 template <int> void A<int>::h();
1198 we need to figure out ARGS, the template arguments from
1199 the context of DECL. This is required for template substitution
1200 of `T' in the function parameter of `g' and template parameter
1201 of `h' in the above examples. Here ARGS corresponds to `int'. */
1208 {
1210 {
1213 else
1215 current_depth++;
1216 }
1218 }
1221 {
1223 tree friend_type;
1224 tree decl_type;
1225 tree friend_args_type;
1226 tree decl_args_type;
1228 /* Make sure that both DECL and FRIEND_DECL are templates or
1229 non-templates. */
1235 {
1236 /* If both are templates, check template parameter list. */
1237 tree friend_parms
1242 friend_parms))
1246 }
1247 else
1255 /* Check if return types match. */
1259 /* Check if function parameter types match, ignoring the
1260 `this' parameter. */
1269 }
1270 else
1271 {
1272 /* DECL is a TYPE_DECL */
1276 /* Make sure that both DECL and FRIEND_DECL are templates or
1277 non-templates. */
1278 is_template
1285 {
1286 tree friend_parms;
1287 /* If both are templates, check the name of the two
1288 TEMPLATE_DECL's first because is_friend didn't. */
1293 /* Now check template parameter list. */
1294 friend_parms
1297 return comp_template_parms
1299 friend_parms);
1300 }
1301 else
1304 }
1305 }
1307 }
1309 /* Register the specialization SPEC as a specialization of TMPL with
1310 the indicated ARGS. IS_FRIEND indicates whether the specialization
1311 is actually just a friend declaration. Returns SPEC, or an
1312 equivalent prior declaration, if available. */
1314 static tree
1316 hashval_t hash)
1317 {
1318 tree fn;
1320 spec_entry elt;
1326 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1327 register it; we want the corresponding TEMPLATE_DECL instead.
1328 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1329 the more obvious `uses_template_parms (spec)' to avoid problems
1330 with default function arguments. In particular, given
1331 something like this:
1333 template <class T> void f(T t1, T t = T())
1335 the default argument expression is not substituted for in an
1336 instantiation unless and until it is actually needed. */
1340 /* We don't put these specializations in the hash table, but we might
1341 want to give an error about a mismatch. */
1343 else
1344 {
1352 slot =
1356 else
1358 }
1360 /* We can sometimes try to re-register a specialization that we've
1361 already got. In particular, regenerate_decl_from_template calls
1362 duplicate_decls which will update the specialization list. But,
1363 we'll still get called again here anyhow. It's more convenient
1364 to simply allow this than to try to prevent it. */
1368 {
1370 {
1373 {
1375 fn);
1377 }
1378 else
1379 {
1380 tree clone;
1381 /* This situation should occur only if the first
1382 specialization is an implicit instantiation, the
1383 second is an explicit specialization, and the
1384 implicit instantiation has not yet been used. That
1385 situation can occur if we have implicitly
1386 instantiated a member function and then specialized
1387 it later.
1389 We can also wind up here if a friend declaration that
1390 looked like an instantiation turns out to be a
1391 specialization:
1393 template <class T> void foo(T);
1394 class S { friend void foo<>(int) };
1395 template <> void foo(int);
1397 We transform the existing DECL in place so that any
1398 pointers to it become pointers to the updated
1399 declaration.
1401 If there was a definition for the template, but not
1402 for the specialization, we want this to look as if
1403 there were no definition, and vice versa. */
1406 /* The call to duplicate_decls will have applied
1407 [temp.expl.spec]:
1409 An explicit specialization of a function template
1410 is inline only if it is explicitly declared to be,
1411 and independently of whether its function template
1412 is.
1414 to the primary function; now copy the inline bits to
1415 the various clones. */
1417 {
1422 }
1426 }
1427 }
1429 {
1431 /* Dup decl failed, but this is a new definition. Set the
1432 line number so any errors match this new
1433 definition. */
1437 }
1438 }
1442 /* A specialization must be declared in the same namespace as the
1443 template it is specializing. */
1449 {
1457 /* TMPL is a forward declaration of a template function; keep a list
1458 of all specializations in case we need to reassign them to a friend
1459 template later in tsubst_friend_function. */
1462 }
1465 }
1467 /* Returns true iff two spec_entry nodes are equivalent. Only compares the
1468 TMPL and ARGS members, ignores SPEC. */
1472 static int
1474 {
1485 }
1487 /* Returns a hash for a template TMPL and template arguments ARGS. */
1489 static hashval_t
1491 {
1494 }
1496 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1497 ignoring SPEC. */
1499 static hashval_t
1501 {
1504 }
1506 /* Recursively calculate a hash value for a template argument ARG, for use
1507 in the hash tables of template specializations. */
1509 hashval_t
1511 {
1523 /* We can get one of these when re-hashing a previous entry in the middle
1524 of substituting into a pack expansion. Just look through it. */
1533 {
1541 {
1546 }
1568 {
1571 {
1574 }
1576 }
1580 {
1583 }
1594 val = iterative_hash_template_arg
1606 val);
1608 val);
1617 /* A lambda can't appear in a template arg, but don't crash on
1618 erroneous input. */
1630 /* Now hash operands as usual. */
1635 }
1638 {
1642 val);
1645 /* Otherwise just compare the types during lookup. */
1654 {
1659 }
1660 }
1663 }
1665 /* Unregister the specialization SPEC as a specialization of TMPL.
1666 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1667 if the SPEC was listed as a specialization of TMPL.
1669 Note that SPEC has been ggc_freed, so we can't look inside it. */
1671 bool
1673 {
1675 spec_entry elt;
1683 {
1688 }
1691 }
1693 /* Like register_specialization, but for local declarations. We are
1694 registering SPEC, an instantiation of TMPL. */
1696 static void
1698 {
1703 }
1705 /* TYPE is a class type. Returns true if TYPE is an explicitly
1706 specialized class. */
1708 bool
1710 {
1714 }
1716 /* Print the list of functions at FNS, going through all the overloads
1717 for each element of the list. Alternatively, FNS can not be a
1718 TREE_LIST, in which case it will be printed together with all the
1719 overloads.
1721 MORE and *STR should respectively be FALSE and NULL when the function
1722 is called from the outside. They are used internally on recursive
1723 calls. print_candidates manages the two parameters and leaves NULL
1724 in *STR when it ends. */
1726 static void
1728 {
1734 {
1738 }
1739 else
1740 {
1743 {
1744 /* Pick the prefix string. */
1746 {
1750 }
1754 }
1757 }
1760 {
1763 }
1764 }
1766 /* Print the list of candidate FNS in an error message. FNS can also
1767 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1769 void
1771 {
1775 }
1777 /* Returns the template (one of the functions given by TEMPLATE_ID)
1778 which can be specialized to match the indicated DECL with the
1779 explicit template args given in TEMPLATE_ID. The DECL may be
1780 NULL_TREE if none is available. In that case, the functions in
1781 TEMPLATE_ID are non-members.
1783 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
1784 specialization of a member template.
1786 The TEMPLATE_COUNT is the number of references to qualifying
1787 template classes that appeared in the name of the function. See
1788 check_explicit_specialization for a more accurate description.
1790 TSK indicates what kind of template declaration (if any) is being
1791 declared. TSK_TEMPLATE indicates that the declaration given by
1792 DECL, though a FUNCTION_DECL, has template parameters, and is
1793 therefore a template function.
1795 The template args (those explicitly specified and those deduced)
1796 are output in a newly created vector *TARGS_OUT.
1798 If it is impossible to determine the result, an error message is
1799 issued. The error_mark_node is returned to indicate failure. */
1801 static tree
1803 tree decl,
1807 tmpl_spec_kind tsk)
1808 {
1809 tree fns;
1810 tree targs;
1811 tree explicit_targs;
1813 /* A TREE_LIST of templates of which DECL may be a specialization.
1814 The TREE_VALUE of each node is a TEMPLATE_DECL. The
1815 corresponding TREE_PURPOSE is the set of template arguments that,
1816 when used to instantiate the template, would produce a function
1817 with the signature of DECL. */
1827 /* We shouldn't be specializing a member template of an
1828 unspecialized class template; we already gave an error in
1829 check_specialization_scope, now avoid crashing. */
1832 {
1835 }
1843 /* Check for baselinks. */
1848 {
1851 }
1853 /* Count the number of template headers specified for this
1854 specialization. */
1862 {
1866 {
1867 tree decl_arg_types;
1868 tree fn_arg_types;
1869 tree insttype;
1871 /* In case of explicit specialization, we need to check if
1872 the number of template headers appearing in the specialization
1873 is correct. This is usually done in check_explicit_specialization,
1874 but the check done there cannot be exhaustive when specializing
1875 member functions. Consider the following code:
1877 template <> void A<int>::f(int);
1878 template <> template <> void A<int>::f(int);
1880 Assuming that A<int> is not itself an explicit specialization
1881 already, the first line specializes "f" which is a non-template
1882 member function, whilst the second line specializes "f" which
1883 is a template member function. So both lines are syntactically
1884 correct, and check_explicit_specialization does not reject
1885 them.
1887 Here, we can do better, as we are matching the specialization
1888 against the declarations. We count the number of template
1889 headers, and we check if they match TEMPLATE_COUNT + 1
1890 (TEMPLATE_COUNT is the number of qualifying template classes,
1891 plus there must be another header for the member template
1892 itself).
1894 Notice that if header_count is zero, this is not a
1895 specialization but rather a template instantiation, so there
1896 is no check we can perform here. */
1900 /* Check that the number of template arguments at the
1901 innermost level for DECL is the same as for FN. */
1909 /* DECL might be a specialization of FN. */
1913 /* For a non-static member function, we need to make sure
1914 that the const qualification is the same. Since
1915 get_bindings does not try to merge the "this" parameter,
1916 we must do the comparison explicitly. */
1922 /* Skip the "this" parameter and, for constructors of
1923 classes with virtual bases, the VTT parameter. A
1924 full specialization of a constructor will have a VTT
1925 parameter, but a template never will. */
1926 decl_arg_types
1928 fn_arg_types
1931 /* Function templates cannot be specializations; there are
1932 no partial specializations of functions. Therefore, if
1933 the type of DECL does not match FN, there is no
1934 match. */
1936 {
1940 }
1942 /* See whether this function might be a specialization of this
1943 template. Suppress access control because we might be trying
1944 to make this specialization a friend, and we have already done
1945 access control for the declaration of the specialization. */
1951 /* We cannot deduce template arguments that when used to
1952 specialize TMPL will produce DECL. */
1955 /* Make sure that the deduced arguments actually work. */
1959 fn_arg_types
1964 /* Save this template, and the arguments deduced. */
1966 }
1968 /* FN is an ordinary member function, and we need a
1969 specialization of a member template. */
1970 ;
1972 /* We can get IDENTIFIER_NODEs here in certain erroneous
1973 cases. */
1974 ;
1976 /* This is just an ordinary non-member function. Nothing can
1977 be a specialization of that. */
1978 ;
1980 /* Cannot specialize functions that are created implicitly. */
1981 ;
1982 else
1983 {
1984 tree decl_arg_types;
1986 /* This is an ordinary member function. However, since
1987 we're here, we can assume it's enclosing class is a
1988 template class. For example,
1990 template <typename T> struct S { void f(); };
1991 template <> void S<int>::f() {}
1993 Here, S<int>::f is a non-template, but S<int> is a
1994 template class. If FN has the same type as DECL, we
1995 might be in business. */
1998 /* Its enclosing class is an explicit specialization
1999 of a template class. This is not a candidate. */
2004 /* The return types differ. */
2007 /* Adjust the type of DECL in case FN is a static member. */
2014 decl_arg_types))
2015 /* They match! */
2017 }
2018 }
2021 {
2022 /* We have:
2024 [temp.expl.spec]
2026 It is possible for a specialization with a given function
2027 signature to be instantiated from more than one function
2028 template. In such cases, explicit specification of the
2029 template arguments must be used to uniquely identify the
2030 function template specialization being specialized.
2032 Note that here, there's no suggestion that we're supposed to
2033 determine which of the candidate templates is most
2034 specialized. However, we, also have:
2036 [temp.func.order]
2038 Partial ordering of overloaded function template
2039 declarations is used in the following contexts to select
2040 the function template to which a function template
2041 specialization refers:
2043 -- when an explicit specialization refers to a function
2044 template.
2046 So, we do use the partial ordering rules, at least for now.
2047 This extension can only serve to make invalid programs valid,
2048 so it's safe. And, there is strong anecdotal evidence that
2049 the committee intended the partial ordering rules to apply;
2050 the EDG front end has that behavior, and John Spicer claims
2051 that the committee simply forgot to delete the wording in
2052 [temp.expl.spec]. */
2055 {
2058 }
2059 }
2062 {
2070 }
2074 {
2080 }
2082 /* We have one, and exactly one, match. */
2084 {
2087 /* DECL is a re-declaration or partial instantiation of a template
2088 function. */
2091 /* It was a specialization of an ordinary member function in a
2092 template class. */
2094 }
2096 /* It was a specialization of a template. */
2099 {
2104 }
2105 else
2108 }
2110 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2111 but with the default argument values filled in from those in the
2112 TMPL_TYPES. */
2114 static tree
2116 tree tmpl_types)
2117 {
2118 tree new_spec_types;
2126 /* Substitute into the rest of the list. */
2127 new_spec_types =
2131 /* Add the default argument for this parameter. */
2134 new_spec_types);
2135 }
2137 /* DECL is an explicit specialization. Replicate default arguments
2138 from the template it specializes. (That way, code like:
2140 template <class T> void f(T = 3);
2141 template <> void f(double);
2142 void g () { f (); }
2144 works, as required.) An alternative approach would be to look up
2145 the correct default arguments at the call-site, but this approach
2146 is consistent with how implicit instantiations are handled. */
2148 static void
2150 {
2151 tree tmpl;
2152 tree spec_types;
2153 tree tmpl_types;
2154 tree new_spec_types;
2155 tree old_type;
2156 tree new_type;
2157 tree t;
2162 /* See if there's anything we need to do. */
2175 {
2176 /* Remove the this pointer, but remember the object's type for
2177 CV quals. */
2183 {
2184 /* DECL may contain more parameters than TMPL due to the extra
2185 in-charge parameter in constructors and destructors. */
2188 }
2190 {
2193 }
2194 }
2196 /* Compute the merged default arguments. */
2197 new_spec_types =
2200 /* Compute the new FUNCTION_TYPE. */
2202 {
2206 new_spec_types);
2209 /* Put the in-charge parameter back. */
2212 new_spec_types);
2216 new_spec_types);
2217 }
2218 else
2220 new_spec_types);
2226 }
2228 /* Return the number of template headers we expect to see for a definition
2229 or specialization of CTYPE or one of its non-template members. */
2231 int
2233 {
2237 {
2238 /* You're supposed to have one `template <...>' for every
2239 template class, but you don't need one for a full
2240 specialization. For example:
2242 template <class T> struct S{};
2243 template <> struct S<int> { void f(); };
2244 void S<int>::f () {}
2246 is correct; there shouldn't be a `template <>' for the
2247 definition of `S<int>::f'. */
2249 /* If CTYPE does not have template information of any
2250 kind, then it is not a template, nor is it nested
2251 within a template. */
2259 }
2262 }
2264 /* Do a simple sanity check on the template headers that precede the
2265 variable declaration DECL. */
2267 void
2269 {
2276 {
2282 "members of an explicitly specialized class are defined "
2284 }
2285 }
2287 /* Check to see if the function just declared, as indicated in
2288 DECLARATOR, and in DECL, is a specialization of a function
2289 template. We may also discover that the declaration is an explicit
2290 instantiation at this point.
2292 Returns DECL, or an equivalent declaration that should be used
2293 instead if all goes well. Issues an error message if something is
2294 amiss. Returns error_mark_node if the error is not easily
2295 recoverable.
2297 FLAGS is a bitmask consisting of the following flags:
2299 2: The function has a definition.
2300 4: The function is a friend.
2302 The TEMPLATE_COUNT is the number of references to qualifying
2303 template classes that appeared in the name of the function. For
2304 example, in
2306 template <class T> struct S { void f(); };
2307 void S<int>::f();
2309 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2310 classes are not counted in the TEMPLATE_COUNT, so that in
2312 template <class T> struct S {};
2313 template <> struct S<int> { void f(); }
2314 template <> void S<int>::f();
2316 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2317 invalid; there should be no template <>.)
2319 If the function is a specialization, it is marked as such via
2320 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2321 is set up correctly, and it is added to the list of specializations
2322 for that template. */
2324 tree
2326 tree decl,
2329 {
2337 tmpl_spec_kind tsk;
2340 {
2343 else
2345 }
2346 else
2350 {
2353 {
2356 }
2358 {
2360 /* This could be something like:
2362 template <class T> void f(T);
2363 class S { friend void f<>(int); } */
2365 else
2366 {
2367 /* This case handles bogus declarations like template <>
2368 template <class T> void f<int>(); */
2371 declarator);
2373 }
2374 }
2378 /* The error has already been reported in
2379 check_specialization_scope. */
2385 /* Fall through. */
2398 decl);
2401 else
2405 /* Fall through. */
2410 else
2416 {
2417 /* This case handles bogus declarations like template <>
2418 template <class T> void f<int>(); */
2423 else
2425 declarator);
2427 }
2430 /* This is a specialization of a member template, without
2431 specialization the containing class. Something like:
2433 template <class T> struct S {
2434 template <class U> void f (U);
2435 };
2436 template <> template <class U> void S<int>::f(U) {}
2438 That's a specialization -- but of the entire template. */
2444 }
2447 {
2451 {
2455 }
2456 }
2459 {
2463 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2465 {
2466 tree fns;
2471 else
2472 {
2473 /* If there is no class context, the explicit instantiation
2474 must be at namespace scope. */
2477 /* Find the namespace binding, using the declaration
2478 context. */
2482 {
2485 }
2486 else
2487 {
2493 }
2494 }
2497 }
2503 {
2505 /* A specialization in class scope. This is invalid,
2506 but the error will already have been flagged by
2507 check_specialization_scope. */
2509 else
2510 {
2511 /* It's not valid to write an explicit instantiation in
2512 class scope, e.g.:
2514 class C { template void f(); }
2516 This case is caught by the parser. However, on
2517 something like:
2519 template class C { void f(); };
2521 (which is invalid) we can get here. The error will be
2522 issued later. */
2523 ;
2524 }
2527 }
2530 IDENTIFIER_NODE))
2531 {
2532 /* Find the list of functions in ctype that have the same
2533 name as the declared function. */
2539 {
2544 {
2545 /* From [temp.expl.spec]:
2547 If such an explicit specialization for the member
2548 of a class template names an implicitly-declared
2549 special member function (clause _special_), the
2550 program is ill-formed.
2552 Similar language is found in [temp.explicit]. */
2555 }
2558 }
2561 {
2565 }
2566 else
2567 {
2569 tree ovl;
2571 /* For a type-conversion operator, we cannot do a
2572 name-based lookup. We might be looking for `operator
2573 int' which will be a specialization of `operator T'.
2574 So, we find *all* the conversion operators, and then
2575 select from them. */
2583 {
2585 /* There are no more conversion functions. */
2588 /* Glue all these conversion functions together
2589 with those we already have. */
2592 }
2593 }
2596 {
2599 }
2600 else
2602 }
2604 /* Figure out what exactly is being specialized at this point.
2605 Note that for an explicit instantiation, even one for a
2606 member function, we cannot tell apriori whether the
2607 instantiation is for a member template, or just a member
2608 function of a template class. Even if a member template is
2609 being instantiated, the member template arguments may be
2610 elided if they can be deduced from the rest of the
2611 declaration. */
2614 member_specialization,
2615 template_count,
2616 tsk);
2619 /* We couldn't figure out what this declaration was
2620 specializing. */
2622 else
2623 {
2627 {
2628 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2629 is done by do_decl_instantiation later. */
2635 {
2636 /* If TMPL is not the most general template (for
2637 example, if TMPL is a friend template that is
2638 injected into namespace scope), then there will
2639 be too many levels of TARGS. Remove some of them
2640 here. */
2642 tree new_targs;
2649 }
2652 }
2654 /* If we thought that the DECL was a member function, but it
2655 turns out to be specializing a static member function,
2656 make DECL a static member function as well. */
2661 /* If this is a specialization of a member template of a
2662 template class, we want to return the TEMPLATE_DECL, not
2663 the specialization of it. */
2665 {
2670 {
2671 tree parm;
2675 /* We want to use the argument list specified in the
2676 definition, not in the original declaration. */
2681 }
2684 }
2686 /* Set up the DECL_TEMPLATE_INFO for DECL. */
2689 /* Inherit default function arguments from the template
2690 DECL is specializing. */
2693 /* This specialization has the same protection as the
2694 template it specializes. */
2698 /* 7.1.1-1 [dcl.stc]
2700 A storage-class-specifier shall not be specified in an
2701 explicit specialization...
2703 The parser rejects these, so unless action is taken here,
2704 explicit function specializations will always appear with
2705 global linkage.
2707 The action recommended by the C++ CWG in response to C++
2708 defect report 605 is to make the storage class and linkage
2709 of the explicit specialization match the templated function:
2711 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
2712 */
2714 {
2718 /* This specialization has the same linkage and visibility as
2719 the function template it specializes. */
2722 {
2725 }
2728 {
2731 }
2732 }
2734 /* If DECL is a friend declaration, declared using an
2735 unqualified name, the namespace associated with DECL may
2736 have been set incorrectly. For example, in:
2738 template <typename T> void f(T);
2739 namespace N {
2740 struct S { friend void f<int>(int); }
2741 }
2743 we will have set the DECL_CONTEXT for the friend
2744 declaration to N, rather than to the global namespace. */
2749 /* This is not really a declaration of a specialization.
2750 It's just the name of an instantiation. But, it's not
2751 a request for an instantiation, either. */
2754 /* This is indeed a specialization. In case of constructors
2755 and destructors, we need in-charge and not-in-charge
2756 versions in V3 ABI. */
2759 /* Register this specialization so that we can find it
2760 again. */
2762 }
2763 }
2766 }
2768 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
2769 parameters. These are represented in the same format used for
2770 DECL_TEMPLATE_PARMS. */
2772 int
2774 {
2775 const_tree p1;
2776 const_tree p2;
2784 {
2796 {
2800 /* If either of the template parameters are invalid, assume
2801 they match for the sake of error recovery. */
2814 }
2815 }
2818 /* One set of parameters has more parameters lists than the
2819 other. */
2823 }
2825 /* Determine whether PARM is a parameter pack. */
2827 bool
2829 {
2830 /* Determine if we have a non-type template parameter pack. */
2837 /* If this is a list of template parameters, we could get a
2838 TYPE_DECL or a TEMPLATE_DECL. */
2842 /* Otherwise it must be a type template parameter. */
2846 }
2848 /* Determine if T is a function parameter pack. */
2850 bool
2852 {
2856 }
2858 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
2859 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
2861 tree
2863 {
2870 }
2872 /* Return true iff the function parameter PARAM_DECL was expanded
2873 from the function parameter pack PACK. */
2875 bool
2877 {
2882 /* The parameter pack and its pack arguments have the same
2883 DECL_PARM_INDEX. */
2885 }
2887 /* Determine whether ARGS describes a variadic template args list,
2888 i.e., one that is terminated by a template argument pack. */
2890 static bool
2892 {
2894 tree last_parm;
2908 }
2910 /* Generate a new name for the parameter pack name NAME (an
2911 IDENTIFIER_NODE) that incorporates its */
2913 static tree
2915 {
2916 /* Munge the name to include the parameter index. */
2917 #define NUMBUF_LEN 128
2931 }
2933 /* Return true if T is a primary function, class or alias template
2934 instantiation. */
2936 bool
2938 {
2952 }
2954 /* Return true if PARM is a template template parameter. */
2956 bool
2958 {
2960 }
2962 /* Return true iff PARM is a DECL representing a type template
2963 parameter. */
2965 bool
2967 {
2972 }
2974 /* Return the template parameters of T if T is a
2975 primary template instantiation, NULL otherwise. */
2977 tree
2979 {
2984 parms = INNERMOST_TEMPLATE_PARMS
2988 }
2990 /* Return the template parameters of the LEVELth level from the full list
2991 of template parameters PARMS. */
2993 tree
2995 {
2996 tree p;
3007 }
3009 /* Returns the template arguments of T if T is a template instantiation,
3010 NULL otherwise. */
3012 tree
3014 {
3022 }
3024 /* Return the argument pack elements of T if T is a template argument pack,
3025 NULL otherwise. */
3027 tree
3029 {
3035 }
3037 /* Structure used to track the progress of find_parameter_packs_r. */
3038 struct find_parameter_pack_data
3039 {
3040 /* TREE_LIST that will contain all of the parameter packs found by
3041 the traversal. */
3044 /* Set of AST nodes that have been visited by the traversal. */
3046 };
3048 /* Identifies all of the argument packs that occur in a template
3049 argument and appends them to the TREE_LIST inside DATA, which is a
3050 find_parameter_pack_data structure. This is a subroutine of
3051 make_pack_expansion and uses_parameter_packs. */
3052 static tree
3054 {
3060 /* Handle type aliases/typedefs. */
3065 {
3072 }
3074 /* Identify whether this is a parameter pack or not. */
3076 {
3091 {
3092 /* We don't want to walk into the type of a PARM_DECL,
3093 because we don't want to see the type parameter pack. */
3096 }
3103 /* Not a parameter pack. */
3105 }
3108 {
3109 /* Add this parameter pack to the list. */
3111 }
3117 /* This switch statement will return immediately if we don't find a
3118 parameter pack. */
3120 {
3125 /* Check the template itself. */
3128 /* Check the template arguments. */
3144 /* Fall through. */
3186 }
3189 }
3191 /* Determines if the expression or type T uses any parameter packs. */
3192 bool
3194 {
3202 }
3204 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3205 representation a base-class initializer into a parameter pack
3206 expansion. If all goes well, the resulting node will be an
3207 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3208 respectively. */
3209 tree
3211 {
3212 tree result;
3221 {
3222 /* The only time we will see a TREE_LIST here is for a base
3223 class initializer. In this case, the TREE_PURPOSE will be a
3224 _TYPE node (representing the base class expansion we're
3225 initializing) and the TREE_VALUE will be a TREE_LIST
3226 containing the initialization arguments.
3228 The resulting expansion looks somewhat different from most
3229 expansions. Rather than returning just one _EXPANSION, we
3230 return a TREE_LIST whose TREE_PURPOSE is a
3231 TYPE_PACK_EXPANSION containing the bases that will be
3232 initialized. The TREE_VALUE will be identical to the
3233 original TREE_VALUE, which is a list of arguments that will
3234 be passed to each base. We do not introduce any new pack
3235 expansion nodes into the TREE_VALUE (although it is possible
3236 that some already exist), because the TREE_PURPOSE and
3237 TREE_VALUE all need to be expanded together with the same
3238 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3239 resulting TREE_PURPOSE will mention the parameter packs in
3240 both the bases and the arguments to the bases. */
3241 tree purpose;
3242 tree value;
3245 /* Determine which parameter packs will be used by the base
3246 class expansion. */
3253 {
3257 }
3260 {
3261 /* Collect the sets of parameter packs used in each of the
3262 initialization arguments. */
3264 {
3265 /* Determine which parameter packs will be expanded in this
3266 argument. */
3269 }
3270 }
3274 /* Create the pack expansion type for the base type. */
3279 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3280 they will rarely be compared to anything. */
3284 }
3289 /* Build the PACK_EXPANSION_* node. */
3290 result = for_types
3295 {
3296 /* Propagate type and const-expression information. */
3299 }
3300 else
3301 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3302 they will rarely be compared to anything. */
3305 /* Determine which parameter packs will be expanded. */
3311 /* Make sure we found some parameter packs. */
3313 {
3316 else
3319 }
3325 }
3327 /* Checks T for any "bare" parameter packs, which have not yet been
3328 expanded, and issues an error if any are found. This operation can
3329 only be done on full expressions or types (e.g., an expression
3330 statement, "if" condition, etc.), because we could have expressions like:
3332 foo(f(g(h(args)))...)
3334 where "args" is a parameter pack. check_for_bare_parameter_packs
3335 should not be called for the subexpressions args, h(args),
3336 g(h(args)), or f(g(h(args))), because we would produce erroneous
3337 error messages.
3339 Returns TRUE and emits an error if there were bare parameter packs,
3340 returns FALSE otherwise. */
3341 bool
3343 {
3359 {
3362 {
3371 else
3376 else
3380 }
3383 }
3386 }
3388 /* Expand any parameter packs that occur in the template arguments in
3389 ARGS. */
3390 tree
3392 {
3398 /* First, determine if we need to expand anything, and the number of
3399 slots we'll need. */
3401 {
3406 {
3410 else
3412 }
3413 else
3414 {
3416 num_result_args++;
3417 }
3418 }
3420 /* If no expansion is necessary, we're done. */
3424 /* Expand arguments. */
3427 non_default_args_count =
3430 {
3433 {
3440 }
3441 else
3442 {
3445 }
3446 }
3450 }
3452 /* Checks if DECL shadows a template parameter.
3454 [temp.local]: A template-parameter shall not be redeclared within its
3455 scope (including nested scopes).
3457 Emits an error and returns TRUE if the DECL shadows a parameter,
3458 returns FALSE otherwise. */
3460 bool
3462 {
3463 tree olddecl;
3465 /* If we're not in a template, we can't possibly shadow a template
3466 parameter. */
3470 /* Figure out what we're shadowing. */
3475 /* If there's no previous binding for this name, we're not shadowing
3476 anything, let alone a template parameter. */
3480 /* If we're not shadowing a template parameter, we're done. Note
3481 that OLDDECL might be an OVERLOAD (or perhaps even an
3482 ERROR_MARK), so we can't just blithely assume it to be a _DECL
3483 node. */
3487 /* We check for decl != olddecl to avoid bogus errors for using a
3488 name inside a class. We check TPFI to avoid duplicate errors for
3489 inline member templates. */
3494 /* Don't complain about the injected class name, as we've already
3495 complained about the class itself. */
3502 }
3504 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
3505 ORIG_LEVEL, DECL, and TYPE. */
3507 static tree
3511 tree decl,
3512 tree type)
3513 {
3524 }
3526 /* Find the canonical type parameter for the given template type
3527 parameter. Returns the canonical type parameter, which may be TYPE
3528 if no such parameter existed. */
3530 static tree
3532 {
3533 tree list;
3547 else
3548 {
3553 }
3554 }
3556 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
3557 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
3558 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
3559 new one is created. */
3561 static tree
3563 tsubst_flags_t complain)
3564 {
3569 {
3588 /* Template template parameters need this. */
3593 }
3596 }
3598 /* Process information from new template parameter PARM and append it
3599 to the LIST being built. This new parameter is a non-type
3600 parameter iff IS_NON_TYPE is true. This new parameter is a
3601 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
3602 is in PARM_LOC. NUM_TEMPLATE_PARMS is the size of the template
3603 parameter list PARM belongs to. This is used used to create a
3604 proper canonical type for the type of PARM that is to be created,
3605 iff PARM is a type. If the size is not known, this parameter shall
3606 be set to 0. */
3608 tree
3611 {
3613 tree defval;
3614 tree err_parm_list;
3621 {
3625 {
3629 else
3631 }
3634 }
3635 else
3639 {
3645 {
3649 }
3650 else
3651 {
3652 /* [temp.param]
3654 The top-level cv-qualifiers on the template-parameter are
3655 ignored when determining its type. */
3658 {
3662 }
3665 {
3666 /* This template parameter is not a parameter pack, but it
3667 should be. Complain about "bare" parameter packs. */
3670 /* Recover by calling this a parameter pack. */
3672 }
3673 }
3675 /* A template parameter is not modifiable. */
3684 processing_template_decl,
3689 }
3690 else
3691 {
3692 tree t;
3696 {
3698 /* This is for distinguishing between real templates and template
3699 template parameters */
3703 }
3704 else
3705 {
3707 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
3710 }
3717 processing_template_decl,
3721 }
3727 }
3729 /* The end of a template parameter list has been reached. Process the
3730 tree list into a parameter vector, converting each parameter into a more
3731 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
3732 as PARM_DECLs. */
3734 tree
3736 {
3741 current_template_parms
3746 {
3750 }
3755 }
3757 /* end_template_decl is called after a template declaration is seen. */
3759 void
3761 {
3767 /* This matches the pushlevel in begin_template_parm_list. */
3772 }
3774 /* Takes a TREE_LIST representing a template parameter and convert it
3775 into an argument suitable to be passed to the type substitution
3776 functions. Note that If the TREE_LIST contains an error_mark
3777 node, the returned argument is error_mark_node. */
3779 static tree
3781 {
3794 {
3798 {
3799 /* Turn this argument into a TYPE_ARGUMENT_PACK
3800 with a single element, which expands T. */
3802 #ifdef ENABLE_CHECKING
3803 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3805 #endif
3810 }
3811 }
3812 else
3813 {
3817 {
3818 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
3819 with a single element, which expands T. */
3822 #ifdef ENABLE_CHECKING
3823 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
3825 #endif
3832 }
3833 }
3835 }
3837 /* Given a set of template parameters, return them as a set of template
3838 arguments. The template parameters are represented as a TREE_VEC, in
3839 the form documented in cp-tree.h for template arguments. */
3841 static tree
3843 {
3844 tree header;
3849 /* If there is only one level of template parameters, we do not
3850 create a TREE_VEC of TREE_VECs. Instead, we return a single
3851 TREE_VEC containing the arguments. */
3856 {
3864 #ifdef ENABLE_CHECKING
3866 #endif
3870 else
3872 }
3875 /* This can happen for template parms of a template template
3876 parameter, e.g:
3878 template<template<class T, class U> class TT> struct S;
3880 Consider the level of the parms of TT; T and U both have
3881 level 2; TT has no template parm of level 1. So in this case
3882 the first element of full_template_args is NULL_TREE. If we
3883 leave it like this TMPL_ARG_DEPTH on args returns 1 instead
3884 of 2. This will make tsubst wrongly consider that T and U
3885 have level 1. Instead, let's create a dummy vector as the
3886 first element of full_template_args so that TMPL_ARG_DEPTH
3887 returns the correct depth for args. */
3890 }
3892 /* Within the declaration of a template, return the currently active
3893 template parameters as an argument TREE_VEC. */
3895 static tree
3897 {
3899 }
3901 /* Update the declared TYPE by doing any lookups which were thought to be
3902 dependent, but are not now that we know the SCOPE of the declarator. */
3904 tree
3906 {
3917 /* Don't bother building up the args in this case. */
3919 {
3920 /* tsubst in the args corresponding to the template parameters,
3921 including auto if present. Most things will be unchanged, but
3922 make_typename_type and tsubst_qualified_id will resolve
3923 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
3926 tree pushed;
3928 {
3932 }
3937 }
3943 {
3946 else
3948 }
3950 }
3952 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
3953 template PARMS. If MEMBER_TEMPLATE_P is true, the new template is
3954 a member template. Used by push_template_decl below. */
3956 static tree
3958 {
3966 }
3968 struct template_parm_data
3969 {
3970 /* The level of the template parameters we are currently
3971 processing. */
3974 /* The index of the specialization argument we are currently
3975 processing. */
3978 /* An array whose size is the number of template parameters. The
3979 elements are nonzero if the parameter has been used in any one
3980 of the arguments processed so far. */
3983 /* An array whose size is the number of template arguments. The
3984 elements are nonzero if the argument makes use of template
3985 parameters of this level. */
3987 };
3989 /* Subroutine of push_template_decl used to see if each template
3990 parameter in a partial specialization is used in the explicit
3991 argument list. If T is of the LEVEL given in DATA (which is
3992 treated as a template_parm_data*), then DATA->PARMS is marked
3993 appropriately. */
3995 static int
3997 {
4003 {
4006 }
4007 else
4008 {
4011 }
4014 {
4017 }
4019 /* Return zero so that for_each_template_parm will continue the
4020 traversal of the tree; we want to mark *every* template parm. */
4022 }
4024 /* Process the partial specialization DECL. */
4026 static tree
4028 {
4034 tree inner_parms;
4035 tree inst;
4048 /* We check that each of the template parameters given in the
4049 partial specialization is used in the argument list to the
4050 specialization. For example:
4052 template <class T> struct S;
4053 template <class T> struct S<T*>;
4055 The second declaration is OK because `T*' uses the template
4056 parameter T, whereas
4058 template <class T> struct S<int>;
4060 is no good. Even trickier is:
4062 template <class T>
4063 struct S1
4064 {
4065 template <class U>
4066 struct S2;
4067 template <class U>
4068 struct S2<T>;
4069 };
4071 The S2<T> declaration is actually invalid; it is a
4072 full-specialization. Of course,
4074 template <class U>
4075 struct S2<T (*)(U)>;
4077 or some such would have been OK. */
4085 {
4090 NULL,
4092 }
4095 {
4096 /* One of the template parms was not used in the
4097 specialization. */
4099 {
4102 }
4105 }
4110 /* [temp.class.spec]
4112 The argument list of the specialization shall not be identical to
4113 the implicit argument list of the primary template. */
4120 /* A partial specialization that replaces multiple parameters of the
4121 primary template with a pack expansion is less specialized for those
4122 parameters. */
4124 {
4126 "primary template because it replaces multiple parameters "
4130 }
4132 /* [temp.class.spec]
4134 A partially specialized non-type argument expression shall not
4135 involve template parameters of the partial specialization except
4136 when the argument expression is a simple identifier.
4138 The type of a template parameter corresponding to a specialized
4139 non-type argument shall not be dependent on a parameter of the
4140 specialization.
4142 Also, we verify that pack expansions only occur at the
4143 end of the argument list. */
4147 {
4154 {
4155 /* Extract the arguments from the argument pack. We'll be
4156 iterating over these in the following loop. */
4159 }
4162 {
4164 /* Get the Jth argument in the parameter pack. */
4168 {
4169 /* Pack expansions must come at the end of the
4170 argument list. */
4173 {
4177 else
4180 }
4181 }
4184 /* We only care about the pattern. */
4190 /* This next line is the `argument expression is not just a
4191 simple identifier' condition and also the `specialized
4192 non-type argument' bit. */
4194 {
4198 arg);
4199 else
4200 {
4201 /* Look at the corresponding template parameter,
4202 marking which template parameters its type depends
4203 upon. */
4207 {
4208 /* We haven't yet initialized TPD2. Do so now. */
4210 /* The number of parameters here is the number in the
4211 main template, which, as checked in the assertion
4212 above, is NARGS. */
4216 }
4218 /* Mark the template parameters. But this time, we're
4219 looking for the template parameters of the main
4220 template, not in the specialization. */
4227 NULL,
4231 {
4232 /* The type depended on some template parameters.
4233 If they are fully specialized in the
4234 specialization, that's OK. */
4243 "type %qT of template argument %qE depends "
4245 "type %qT of template argument %qE depends "
4247 type,
4248 arg);
4249 }
4250 }
4251 }
4252 }
4253 }
4255 /* We should only get here once. */
4265 {
4269 {
4273 "partial specialization of %qT after instantiation "
4275 }
4276 }
4279 }
4281 /* Check that a template declaration's use of default arguments and
4282 parameter packs is not invalid. Here, PARMS are the template
4283 parameters. IS_PRIMARY is true if DECL is the thing declared by
4284 a primary template. IS_PARTIAL is true if DECL is a partial
4285 specialization.
4287 IS_FRIEND_DECL is nonzero if DECL is a friend function template
4288 declaration (but not a definition); 1 indicates a declaration, 2
4289 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4290 emitted for extraneous default arguments.
4292 Returns TRUE if there were no errors found, FALSE otherwise. */
4294 bool
4297 {
4300 tree parm_level;
4303 /* [temp.param]
4305 A default template-argument shall not be specified in a
4306 function template declaration or a function template definition, nor
4307 in the template-parameter-list of the definition of a member of a
4308 class template. */
4311 /* You can't have a function template declaration in a local
4312 scope, nor you can you define a member of a class template in a
4313 local scope. */
4319 /* A lambda doesn't have an explicit declaration; don't complain
4320 about the parms of the enclosing class. */
4327 /* If this is either a friend defined in the scope of the class
4328 or a member function. */
4334 /* And, if it was a member function, it really was defined in
4335 the scope of the class. */
4338 /* We already checked these parameters when the template was
4339 declared, so there's no need to do it again now. This function
4340 was defined in class scope, but we're processing it's body now
4341 that the class is complete. */
4344 /* Core issue 226 (C++0x only): the following only applies to class
4345 templates. */
4348 {
4349 /* [temp.param]
4351 If a template-parameter has a default template-argument, all
4352 subsequent template-parameters shall have a default
4353 template-argument supplied. */
4355 {
4362 {
4372 {
4374 /* For better subsequent error-recovery, we indicate that
4375 there should have been a default argument. */
4378 }
4380 && !is_friend_decl
4381 /* Don't complain about an enclosing partial
4382 specialization. */
4387 {
4388 /* A primary class template can only have one
4389 parameter pack, at the end of the template
4390 parameter list. */
4395 else
4403 }
4404 }
4405 }
4406 }
4409 || is_partial
4410 || !is_primary
4412 /* For an ordinary class template, default template arguments are
4413 allowed at the innermost level, e.g.:
4414 template <class T = int>
4415 struct S {};
4416 but, in a partial specialization, they're not allowed even
4417 there, as we have in [temp.class.spec]:
4419 The template parameter list of a specialization shall not
4420 contain default template argument values.
4422 So, for a partial specialization, or for a function template
4423 (in C++98/C++03), we look at all of them. */
4424 ;
4425 else
4426 /* But, for a primary class template that is not a partial
4427 specialization we look at all template parameters except the
4428 innermost ones. */
4431 /* Figure out what error message to issue. */
4444 else
4448 /* If we're inside a class definition, there's no need to
4449 examine the parameters to the class itself. On the one
4450 hand, they will be checked when the class is defined, and,
4451 on the other, default arguments are valid in things like:
4452 template <class T = double>
4453 struct S { template <class U> void f(U); };
4454 Here the default argument for `S' has no bearing on the
4455 declaration of `f'. */
4457 else
4458 /* Check everything. */
4464 {
4471 {
4476 {
4478 {
4485 }
4487 /* Clear out the default argument so that we are not
4488 confused later. */
4490 }
4491 }
4493 /* At this point, if we're still interested in issuing messages,
4494 they must apply to classes surrounding the object declared. */
4498 }
4501 }
4503 /* Worker for push_template_decl_real, called via
4504 for_each_template_parm. DATA is really an int, indicating the
4505 level of the parameters we are interested in. If T is a template
4506 parameter of that level, return nonzero. */
4508 static int
4510 {
4516 else
4519 }
4521 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
4522 parameters given by current_template_args, or reuses a
4523 previously existing one, if appropriate. Returns the DECL, or an
4524 equivalent one, if it is replaced via a call to duplicate_decls.
4526 If IS_FRIEND is true, DECL is a friend declaration. */
4528 tree
4530 {
4531 tree tmpl;
4532 tree args;
4533 tree info;
4534 tree ctx;
4538 /* True if the template is a member template, in the sense of
4539 [temp.mem]. */
4545 /* See if this is a partial specialization. */
4554 /* For a friend, we want the context of the friend function, not
4555 the type of which it is a friend. */
4559 /* In the case of a virtual function, we want the class in which
4560 it is defined. */
4562 else
4563 /* Otherwise, if we're currently defining some class, the DECL
4564 is assumed to be a member of the class. */
4573 /* See if this is a primary template. */
4575 /* A friend template that specifies a class context, i.e.
4576 template <typename T> friend void A<T>::f();
4577 is not primary. */
4579 else
4583 {
4588 {
4591 }
4593 {
4595 {
4596 /* [temp.mem]
4598 A destructor shall not be a member template. */
4601 }
4608 {
4609 /* [basic.stc.dynamic.allocation]
4611 An allocation function can be a function
4612 template. ... Template allocation functions shall
4613 have two or more parameters. */
4616 }
4617 }
4623 /* alias-declaration */
4625 else
4626 {
4629 }
4630 }
4632 /* Check to see that the rules regarding the use of default
4633 arguments are not being violated. */
4637 /* Ensure that there are no parameter packs in the type of this
4638 declaration that have not been expanded. */
4640 {
4641 /* Check each of the arguments individually to see if there are
4642 any bare parameter packs. */
4648 {
4651 {
4652 /* This is a PARM_DECL that contains unexpanded parameter
4653 packs. We have already complained about this in the
4654 check_for_bare_parameter_packs call, so just replace
4655 these types with ERROR_MARK_NODE. */
4658 }
4662 }
4664 /* Check for bare parameter packs in the return type and the
4665 exception specifiers. */
4667 /* Errors were already issued, set return type to int
4668 as the frontend doesn't expect error_mark_node as
4669 the return type. */
4673 }
4678 {
4681 }
4694 {
4699 /* If DECL is a TYPE_DECL for a class-template, then there won't
4700 be DECL_LANG_SPECIFIC. The information equivalent to
4701 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
4705 {
4706 /* Since a template declaration already existed for this
4707 class-type, we must be redeclaring it here. Make sure
4708 that the redeclaration is valid. */
4710 current_template_parms);
4711 /* We don't need to create a new TEMPLATE_DECL; just use the
4712 one we already had. */
4714 }
4715 else
4716 {
4718 member_template_p);
4723 {
4724 /* A specialization of a member template of a template
4725 class. */
4729 }
4730 }
4731 }
4732 else
4733 {
4739 {
4742 }
4750 {
4751 tree new_tmpl;
4753 /* The declaration is a specialization of a member
4754 template, declared outside the class. Therefore, the
4755 innermost template arguments will be NULL, so we
4756 replace them with the arguments determined by the
4757 earlier call to check_explicit_specialization. */
4760 new_tmpl
4762 member_template_p);
4772 args,
4775 }
4777 /* Make sure the template headers we got make sense. */
4782 {
4785 }
4786 else
4788 {
4793 {
4797 else
4801 /* Avoid crash in import_export_decl. */
4804 }
4809 /* Can happen in erroneous input. */
4811 else
4815 }
4817 /* Check that the parms are used in the appropriate qualifying scopes
4818 in the declarator. */
4822 {
4828 /* Avoid crash in import_export_decl. */
4831 }
4832 }
4837 /* Push template declarations for global functions and types. Note
4838 that we do not try to push a global template friend declared in a
4839 template class; such a thing may well depend on the template
4840 parameters of the class. */
4843 {
4848 /* Hide template friend classes that haven't been declared yet. */
4850 {
4853 }
4854 }
4857 {
4863 {
4866 /* It is a conversion operator. See if the type converted to
4867 depends on innermost template operands. */
4870 depth))
4872 }
4874 /* Give template template parms a DECL_CONTEXT of the template
4875 for which they are a parameter. */
4878 {
4882 }
4883 }
4885 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
4886 back to its most general template. If TMPL is a specialization,
4887 ARGS may only have the innermost set of arguments. Add the missing
4888 argument levels if necessary. */
4896 else
4897 {
4902 }
4905 }
4907 tree
4909 {
4911 }
4913 /* FN is an inheriting constructor that inherits from the constructor
4914 template INHERITED; turn FN into a constructor template with a matching
4915 template header. */
4917 tree
4919 {
4920 tree inner_parms
4923 tree parms
4934 }
4936 /* Called when a class template TYPE is redeclared with the indicated
4937 template PARMS, e.g.:
4939 template <class T> struct S;
4940 template <class T> struct S {}; */
4942 bool
4944 {
4945 tree tmpl;
4946 tree tmpl_parms;
4950 {
4953 }
4957 /* The type is nested in some template class. Nothing to worry
4958 about here; there are no new template parameters for the nested
4959 type. */
4963 {
4965 tmpl);
4967 }
4973 {
4983 }
4986 {
4987 tree tmpl_parm;
4988 tree parm;
4989 tree tmpl_default;
4990 tree parm_default;
5004 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5005 TEMPLATE_DECL. */
5015 {
5019 }
5022 {
5023 /* We have in [temp.param]:
5025 A template-parameter may not be given default arguments
5026 by two different declarations in the same scope. */
5031 }
5034 /* Update the previous template parameters (which are the ones
5035 that will really count) with the new default value. */
5038 /* Update the new parameters, too; they'll be used as the
5039 parameters for any members. */
5041 }
5044 }
5046 /* Simplify EXPR if it is a non-dependent expression. Returns the
5047 (possibly simplified) expression. */
5049 tree
5051 {
5055 /* If we're in a template, but EXPR isn't value dependent, simplify
5056 it. We're supposed to treat:
5058 template <typename T> void f(T[1 + 1]);
5059 template <typename T> void f(T[2]);
5061 as two declarations of the same function, for example. */
5066 {
5067 HOST_WIDE_INT saved_processing_template_decl;
5073 complain,
5078 }
5080 }
5082 tree
5084 {
5086 }
5088 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5089 template declaration, or a TYPE_DECL for an alias declaration. */
5091 bool
5093 {
5101 }
5103 /* Return TRUE iff is a specialization of an alias template. */
5105 bool
5107 {
5115 }
5117 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
5118 must be a function or a pointer-to-function type, as specified
5119 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
5120 and check that the resulting function has external linkage. */
5122 static tree
5124 {
5127 linkage_kind linkage;
5139 /* [temp.arg.nontype]/1
5141 A template-argument for a non-type, non-template template-parameter
5142 shall be one of:
5143 [...]
5144 -- the address of an object or function with external [C++11: or
5145 internal] linkage. */
5148 {
5152 else
5155 }
5159 {
5164 else
5169 }
5172 }
5174 /* Subroutine of convert_nontype_argument.
5175 Check if EXPR of type TYPE is a valid pointer-to-member constant.
5176 Emit an error otherwise. */
5178 static bool
5180 tsubst_flags_t complain)
5181 {
5188 {
5192 }
5194 }
5196 /* Returns TRUE iff the address of OP is value-dependent.
5198 14.6.2.4 [temp.dep.temp]:
5199 A non-integral non-type template-argument is dependent if its type is
5200 dependent or it has either of the following forms
5201 qualified-id
5202 & qualified-id
5203 and contains a nested-name-specifier which specifies a class-name that
5204 names a dependent type.
5206 We generalize this to just say that the address of a member of a
5207 dependent class is value-dependent; the above doesn't cover the
5208 address of a static data member named with an unqualified-id. */
5210 static bool
5212 {
5213 /* We could use get_inner_reference here, but there's no need;
5214 this is only relevant for template non-type arguments, which
5215 can only be expressed as &id-expression. */
5217 {
5221 }
5224 }
5226 /* The next set of functions are used for providing helpful explanatory
5227 diagnostics for failed overload resolution. Their messages should be
5228 indented by two spaces for consistency with the messages in
5229 call.c */
5231 static int
5233 {
5235 }
5237 static int
5239 {
5244 }
5246 static int
5248 {
5250 }
5252 static int
5254 {
5260 }
5262 static int
5264 {
5268 }
5270 static int
5272 {
5275 " template parameter %qD is not a parameter pack, but "
5279 }
5281 static int
5283 {
5286 " template argument %qE does not match "
5290 }
5292 static int
5294 {
5298 }
5300 static int
5302 {
5308 }
5310 static int
5312 {
5314 {
5319 else
5321 " deduced conflicting values for non-type parameter "
5323 }
5325 }
5327 static int
5329 {
5332 " variable-sized array type %qT is not "
5334 arg);
5336 }
5338 static int
5340 {
5344 arg);
5346 }
5348 static int
5350 {
5357 }
5359 static int
5361 {
5363 }
5365 static int
5367 {
5369 }
5371 static int
5374 {
5379 }
5381 static int
5384 {
5387 {
5395 }
5397 }
5399 static int
5401 {
5404 " template parameters of a template template argument are "
5407 }
5409 static int
5411 {
5417 }
5419 static int
5421 {
5426 }
5428 static int
5430 {
5434 arg);
5436 }
5438 /* Attempt to convert the non-type template parameter EXPR to the
5439 indicated TYPE. If the conversion is successful, return the
5440 converted value. If the conversion is unsuccessful, return
5441 NULL_TREE if we issued an error message, or error_mark_node if we
5442 did not. We issue error messages for out-and-out bad template
5443 parameters, but not simply because the conversion failed, since we
5444 might be just trying to do argument deduction. Both TYPE and EXPR
5445 must be non-dependent.
5447 The conversion follows the special rules described in
5448 [temp.arg.nontype], and it is much more strict than an implicit
5449 conversion.
5451 This function is called twice for each template argument (see
5452 lookup_template_class for a more accurate description of this
5453 problem). This means that we need to handle expressions which
5454 are not valid in a C++ source, but can be created from the
5455 first call (for instance, casts to perform conversions). These
5456 hacks can go away after we fix the double coercion problem. */
5458 static tree
5460 {
5461 tree expr_type;
5463 /* Detect immediately string literals as invalid non-type argument.
5464 This special-case is not needed for correctness (we would easily
5465 catch this later), but only to provide better diagnostic for this
5466 common user mistake. As suggested by DR 100, we do not mention
5467 linkage issues in the diagnostic as this is not the point. */
5468 /* FIXME we're making this OK. */
5470 {
5476 }
5478 /* Add the ADDR_EXPR now for the benefit of
5479 value_dependent_expression_p. */
5482 {
5486 }
5488 /* If we are in a template, EXPR may be non-dependent, but still
5489 have a syntactic, rather than semantic, form. For example, EXPR
5490 might be a SCOPE_REF, rather than the VAR_DECL to which the
5491 SCOPE_REF refers. Preserving the qualifying scope is necessary
5492 so that access checking can be performed when the template is
5493 instantiated -- but here we need the resolved form so that we can
5494 convert the argument. */
5505 else
5508 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
5509 to a non-type argument of "nullptr". */
5513 /* In C++11, integral or enumeration non-type template arguments can be
5514 arbitrary constant expressions. Pointer and pointer to
5515 member arguments can be general constant expressions that evaluate
5516 to a null value, but otherwise still need to be of a specific form. */
5518 {
5520 /* A PTRMEM_CST is already constant, and a valid template
5521 argument for a parameter of pointer to member type, we just want
5522 to leave it in that form rather than lower it to a
5527 {
5532 }
5533 }
5535 /* HACK: Due to double coercion, we can get a
5536 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
5537 which is the tree that we built on the first call (see
5538 below when coercing to reference to object or to reference to
5539 function). We just strip everything and get to the arg.
5540 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
5541 for examples. */
5543 {
5549 {
5550 /* ??? Maybe we could use convert_from_reference here, but we
5551 would need to relax its constraints because the NOP_EXPR
5552 could actually change the type to something more cv-qualified,
5553 and this is not folded by convert_from_reference. */
5558 && (same_type_ignoring_top_level_qualifiers_p
5561 {
5564 }
5565 }
5566 }
5568 /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the
5569 parameter is a pointer to object, through decay and
5570 qualification conversion. Let's strip everything. */
5572 {
5576 /* Skip the ADDR_EXPR only if it is part of the decay for
5577 an array. Otherwise, it is part of the original argument
5578 in the source code. */
5582 }
5584 /* [temp.arg.nontype]/5, bullet 1
5586 For a non-type template-parameter of integral or enumeration type,
5587 integral promotions (_conv.prom_) and integral conversions
5588 (_conv.integral_) are applied. */
5590 {
5599 /* Notice that there are constant expressions like '4 % 0' which
5600 do not fold into integer constants. */
5602 {
5604 {
5615 /* else cxx_constant_value complained but gave us
5616 a real constant, so go ahead. */
5618 }
5619 else
5621 }
5623 /* Avoid typedef problems. */
5626 }
5627 /* [temp.arg.nontype]/5, bullet 2
5629 For a non-type template-parameter of type pointer to object,
5630 qualification conversions (_conv.qual_) and the array-to-pointer
5631 conversion (_conv.array_) are applied. */
5633 {
5634 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
5636 A template-argument for a non-type, non-template template-parameter
5637 shall be one of: [...]
5639 -- the name of a non-type template-parameter;
5640 -- the address of an object or function with external linkage, [...]
5641 expressed as "& id-expression" where the & is optional if the name
5642 refers to a function or array, or if the corresponding
5643 template-parameter is a reference.
5645 Here, we do not care about functions, as they are invalid anyway
5646 for a parameter of type pointer-to-object. */
5649 /* Non-type template parameters are OK. */
5650 ;
5655 {
5657 {
5659 "because %qD is a variable, not the address of "
5663 }
5664 /* Other values, like integer constants, might be valid
5665 non-type arguments of some other type. */
5667 }
5668 else
5669 {
5670 tree decl;
5675 {
5680 }
5682 {
5687 }
5689 {
5694 }
5695 }
5704 }
5705 /* [temp.arg.nontype]/5, bullet 3
5707 For a non-type template-parameter of type reference to object, no
5708 conversions apply. The type referred to by the reference may be more
5709 cv-qualified than the (otherwise identical) type of the
5710 template-argument. The template-parameter is bound directly to the
5711 template-argument, which must be an lvalue. */
5713 {
5715 expr_type))
5719 {
5723 }
5726 {
5730 }
5732 /* [temp.arg.nontype]/1
5734 A template-argument for a non-type, non-template template-parameter
5735 shall be one of: [...]
5737 -- the address of an object or function with external linkage. */
5740 {
5743 {
5745 "because a reference variable does not have a constant "
5748 }
5749 }
5752 {
5757 }
5760 {
5765 }
5768 }
5769 /* [temp.arg.nontype]/5, bullet 4
5771 For a non-type template-parameter of type pointer to function, only
5772 the function-to-pointer conversion (_conv.func_) is applied. If the
5773 template-argument represents a set of overloaded functions (or a
5774 pointer to such), the matching function is selected from the set
5775 (_over.over_). */
5777 {
5778 /* If the argument is a template-id, we might not have enough
5779 context information to decay the pointer. */
5781 {
5785 }
5788 /* Null pointer values are OK in C++11. */
5794 }
5795 /* [temp.arg.nontype]/5, bullet 5
5797 For a non-type template-parameter of type reference to function, no
5798 conversions apply. If the template-argument represents a set of
5799 overloaded functions, the matching function is selected from the set
5800 (_over.over_). */
5802 {
5804 {
5809 }
5816 }
5817 /* [temp.arg.nontype]/5, bullet 6
5819 For a non-type template-parameter of type pointer to member function,
5820 no conversions apply. If the template-argument represents a set of
5821 overloaded member functions, the matching member function is selected
5822 from the set (_over.over_). */
5824 {
5829 /* [temp.arg.nontype] bullet 1 says the pointer to member
5830 expression must be a pointer-to-member constant. */
5834 /* There is no way to disable standard conversions in
5835 resolve_address_of_overloaded_function (called by
5836 instantiate_type). It is possible that the call succeeded by
5837 converting &B::I to &D::I (where B is a base of D), so we need
5838 to reject this conversion here.
5840 Actually, even if there was a way to disable standard conversions,
5841 it would still be better to reject them here so that we can
5842 provide a superior diagnostic. */
5844 {
5848 /* If we are just one standard conversion off, explain. */
5853 }
5854 }
5855 /* [temp.arg.nontype]/5, bullet 7
5857 For a non-type template-parameter of type pointer to data member,
5858 qualification conversions (_conv.qual_) are applied. */
5860 {
5861 /* [temp.arg.nontype] bullet 1 says the pointer to member
5862 expression must be a pointer-to-member constant. */
5869 }
5871 {
5873 {
5877 }
5879 }
5880 /* A template non-type parameter must be one of the above. */
5881 else
5884 /* Sanity check: did we actually convert the argument to the
5885 right type? */
5889 }
5891 /* Subroutine of coerce_template_template_parms, which returns 1 if
5892 PARM_PARM and ARG_PARM match using the rule for the template
5893 parameters of template template parameters. Both PARM and ARG are
5894 template parameters; the rest of the arguments are the same as for
5895 coerce_template_template_parms.
5896 */
5897 static int
5899 tree arg,
5900 tsubst_flags_t complain,
5901 tree in_decl,
5902 tree outer_args)
5903 {
5912 {
5914 /* We encounter instantiations of templates like
5915 template <template <template <class> class> class TT>
5916 class C; */
5917 {
5924 }
5925 /* Fall through. */
5930 /* Argument is a parameter pack but parameter is not. */
5935 /* The tsubst call is used to handle cases such as
5937 template <int> class C {};
5938 template <class T, template <T> class TT> class D {};
5939 D<int, C> d;
5941 i.e. the parameter list of TT depends on earlier parameters. */
5943 && !same_type_p
5950 /* Argument is a parameter pack but parameter is not. */
5957 }
5960 }
5963 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
5964 template template parameters. Both PARM_PARMS and ARG_PARMS are
5965 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
5966 or PARM_DECL.
5968 Consider the example:
5969 template <class T> class A;
5970 template<template <class U> class TT> class B;
5972 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
5973 the parameters to A, and OUTER_ARGS contains A. */
5975 static int
5977 tree arg_parms,
5978 tsubst_flags_t complain,
5979 tree in_decl,
5980 tree outer_args)
5981 {
5992 /* Determine whether we have a parameter pack at the end of the
5993 template template parameter's template parameter list. */
5995 {
6002 {
6016 }
6017 }
6023 /* Check all of the template parameters except the parameter pack at
6024 the end (if any). */
6026 {
6035 outer_args))
6038 }
6041 {
6042 /* Check each of the template parameters in the template
6043 argument against the template parameter pack at the end of
6044 the template template parameter. */
6051 {
6058 outer_args))
6060 }
6061 }
6064 }
6066 /* Verifies that the deduced template arguments (in TARGS) for the
6067 template template parameters (in TPARMS) represent valid bindings,
6068 by comparing the template parameter list of each template argument
6069 to the template parameter list of its corresponding template
6070 template parameter, in accordance with DR150. This
6071 routine can only be called after all template arguments have been
6072 deduced. It will return TRUE if all of the template template
6073 parameter bindings are okay, FALSE otherwise. */
6074 bool
6076 {
6080 /* We're dealing with template parms in this process. */
6086 {
6091 {
6096 {
6097 /* Look inside the argument pack. */
6100 }
6103 {
6107 /* Extract the next argument from the argument
6108 pack. */
6112 /* Look at the pattern of the pack expansion. */
6115 /* Extract the template parameters from the template
6116 argument. */
6122 /* Verify that we can coerce the template template
6123 parameters from the template argument to the template
6124 parameter. This requires an exact match. */
6126 && !coerce_template_template_parms
6128 targ_parms,
6129 tf_none,
6130 tparm,
6131 targs))
6132 {
6135 }
6136 }
6137 }
6138 }
6140 out:
6144 }
6146 /* Since type attributes aren't mangled, we need to strip them from
6147 template type arguments. */
6149 static tree
6151 {
6152 tree mv;
6159 {
6164 }
6166 }
6168 /* Convert the indicated template ARG as necessary to match the
6169 indicated template PARM. Returns the converted ARG, or
6170 error_mark_node if the conversion was unsuccessful. Error and
6171 warning messages are issued under control of COMPLAIN. This
6172 conversion is for the Ith parameter in the parameter list. ARGS is
6173 the full set of template arguments deduced so far. */
6175 static tree
6177 tree arg,
6178 tree args,
6179 tsubst_flags_t complain,
6181 tree in_decl)
6182 {
6183 tree orig_arg;
6184 tree val;
6189 {
6190 /* The template argument was the name of some
6191 member function. That's usually
6192 invalid, but static members are OK. In any
6193 case, grab the underlying fields/functions
6194 and issue an error later if required. */
6197 }
6205 /* When determining whether an argument pack expansion is a template,
6206 look at the pattern. */
6210 /* Deal with an injected-class-name used as a template template arg. */
6212 {
6215 {
6225 }
6226 }
6228 is_tmpl_type =
6244 {
6246 {
6250 }
6253 "to refer to a type member of a template parameter, "
6258 typename_type,
6259 complain);
6262 }
6264 {
6266 {
6268 {
6278 else
6280 }
6281 }
6283 }
6285 {
6287 {
6293 else
6295 }
6297 }
6300 {
6302 {
6306 /* The number of argument required is not known yet.
6307 Just accept it for now. */
6309 else
6310 {
6312 tree argparm;
6318 args))
6319 {
6322 /* TEMPLATE_TEMPLATE_PARM node is preferred over
6323 TEMPLATE_DECL. */
6325 {
6330 }
6331 }
6332 else
6333 {
6335 {
6341 }
6344 }
6345 }
6346 }
6347 else
6349 /* We only form one instance of each template specialization.
6350 Therefore, if we use a non-canonical variant (i.e., a
6351 typedef), any future messages referring to the type will use
6352 the typedef, which is confusing if those future uses do not
6353 themselves also use the typedef. */
6356 }
6357 else
6358 {
6365 {
6368 else
6369 {
6370 /* Not sure if this is reachable, but it doesn't hurt
6371 to be robust. */
6374 }
6375 }
6378 /* We used to call digest_init here. However, digest_init
6379 will report errors, which we don't want when complain
6380 is zero. More importantly, digest_init will try too
6381 hard to convert things: for example, `0' should not be
6382 converted to pointer type at this point according to
6383 the standard. Accepting this is not merely an
6384 extension, since deciding whether or not these
6385 conversions can occur is part of determining which
6386 function template to call, or whether a given explicit
6387 argument specification is valid. */
6389 else
6398 {
6399 /* Strip typedefs from the SCOPE_REF. */
6402 complain);
6405 }
6406 }
6409 }
6411 /* Coerces the remaining template arguments in INNER_ARGS (from
6412 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
6413 Returns the coerced argument pack. PARM_IDX is the position of this
6414 parameter in the template parameter list. ARGS is the original
6415 template argument list. */
6416 static tree
6419 tree args,
6420 tree inner_args,
6422 tree new_args,
6424 tree in_decl,
6425 tsubst_flags_t complain)
6426 {
6429 tree packed_args;
6430 tree argument_pack;
6440 {
6441 /* When the template parameter is a non-type template
6442 parameter pack whose type uses parameter packs, we need
6443 to look at each of the template arguments
6444 separately. Build a vector of the types for these
6445 non-type template parameters in PACKED_TYPES. */
6446 tree expansion
6454 /* Check that we have the right number of arguments. */
6458 {
6459 int needed_parms
6464 }
6466 /* If we aren't able to check the actual arguments now
6467 (because they haven't been expanded yet), we can at least
6468 verify that all of the types used for the non-type
6469 template parameter pack are, in fact, valid for non-type
6470 template parameters. */
6473 {
6476 {
6480 }
6481 }
6482 }
6484 /* Convert the remaining arguments, which will be a part of the
6485 parameter pack "parm". */
6487 {
6492 {
6493 /* When we have a vector of types (corresponding to the
6494 non-type template parameter pack that uses parameter
6495 packs in its type, as mention above), and the
6496 argument is not an expansion (which expands to a
6497 currently unknown number of arguments), clone the
6498 parm and give it the next type in PACKED_TYPES. */
6502 }
6505 {
6508 }
6509 else
6512 in_decl);
6516 }
6521 else
6522 {
6527 }
6530 #ifdef ENABLE_CHECKING
6533 #endif
6535 }
6537 /* Returns true if the template argument vector ARGS contains
6538 any pack expansions, false otherwise. */
6540 static bool
6542 {
6549 }
6551 /* Convert all template arguments to their appropriate types, and
6552 return a vector containing the innermost resulting template
6553 arguments. If any error occurs, return error_mark_node. Error and
6554 warning messages are issued under control of COMPLAIN.
6556 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
6557 for arguments not specified in ARGS. Otherwise, if
6558 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
6559 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
6560 USE_DEFAULT_ARGS is false, then all arguments must be specified in
6561 ARGS. */
6563 static tree
6565 tree args,
6566 tree in_decl,
6567 tsubst_flags_t complain,
6570 {
6572 tree inner_args;
6573 tree new_args;
6574 tree new_inner_args;
6578 /* When used as a boolean value, indicates whether this is a
6579 variadic template parameter list. Since it's an int, we can also
6580 subtract it from nparms to get the number of non-variadic
6581 parameters. */
6590 /* Determine if there are any parameter packs. */
6592 {
6598 }
6601 /* If there are no parameters that follow a parameter pack, we need to
6602 expand any argument packs so that we can deduce a parameter pack from
6603 some non-packed args followed by an argument pack, as in variadic85.C.
6604 If there are such parameters, we need to leave argument packs intact
6605 so the arguments are assigned properly. This can happen when dealing
6606 with a nested class inside a partial specialization of a class
6607 template, as in variadic92.C, or when deducing a template parameter pack
6608 from a sub-declarator, as in variadic114.C. */
6615 && require_all_args
6617 && (!use_default_args
6620 {
6622 {
6624 {
6628 }
6629 else
6635 }
6638 }
6640 /* We need to evaluate the template arguments, even though this
6641 template-id may be nested within a "sizeof". */
6649 {
6650 tree arg;
6651 tree parm;
6653 /* Get the Ith template parameter. */
6657 {
6660 }
6662 /* Calculate the next argument. */
6665 else
6670 {
6671 /* All remaining arguments will be placed in the
6672 template parameter pack PARM. */
6678 /* Store this argument. */
6680 lost++;
6683 /* We are done with all of the arguments. */
6687 }
6689 {
6691 {
6692 /* We don't know how many args we have yet, just
6693 use the unconverted ones for now. */
6696 }
6697 }
6699 {
6700 /* There must be a default arg in this case. */
6703 /* The position of the first default template argument,
6704 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
6705 Record that. */
6708 }
6709 else
6713 {
6716 }
6718 /* This only occurs if there was an error in the template
6719 parameter list itself (which we would already have
6720 reported) that we are trying to recover from, e.g., a class
6721 template with a parameter list such as
6722 template<typename..., typename>. */
6724 else
6730 lost++;
6732 }
6739 #ifdef ENABLE_CHECKING
6743 #endif
6746 }
6748 /* Like coerce_template_parms. If PARMS represents all template
6749 parameters levels, this function returns a vector of vectors
6750 representing all the resulting argument levels. Note that in this
6751 case, only the innermost arguments are coerced because the
6752 outermost ones are supposed to have been coerced already.
6754 Otherwise, if PARMS represents only (the innermost) vector of
6755 parameters, this function returns a vector containing just the
6756 innermost resulting arguments. */
6758 static tree
6760 tree args,
6761 tree in_decl,
6762 tsubst_flags_t complain,
6765 {
6768 tree coerced_args;
6771 {
6773 tree level;
6779 {
6780 tree l;
6784 require_all_args,
6785 use_default_args);
6786 else
6793 }
6794 }
6795 else
6798 require_all_args,
6799 use_default_args);
6801 }
6803 /* Returns 1 if template args OT and NT are equivalent. */
6805 static int
6807 {
6814 /* For member templates */
6823 {
6840 }
6842 {
6843 /* We get here probably because we are in the middle of substituting
6844 into the pattern of a pack expansion. In that case the
6845 ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are
6846 interested in. So we want to use the initial pack argument for
6847 the comparison. */
6852 }
6857 else
6859 }
6861 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
6862 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
6863 NEWARG_PTR with the offending arguments if they are non-NULL. */
6865 static int
6868 {
6881 {
6886 {
6892 }
6893 }
6895 }
6897 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets
6898 of template arguments. Returns 0 otherwise. */
6900 int
6902 {
6904 }
6906 static void
6908 {
6918 /* We are called both from instantiate_decl, where we've already had a
6919 tinst_level pushed, and instantiate_template, where we haven't.
6920 Compensate. */
6931 else
6940 }
6943 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
6944 ARGLIST. Valid choices for FNS are given in the cp-tree.def
6945 documentation for TEMPLATE_ID_EXPR. */
6947 tree
6949 {
6950 tree type;
6958 {
6961 }
6964 {
6966 unknown_type_node,
6968 arglist);
6970 }
6977 }
6979 /* Within the scope of a template class S<T>, the name S gets bound
6980 (in build_self_reference) to a TYPE_DECL for the class, not a
6981 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
6982 or one of its enclosing classes, and that type is a template,
6983 return the associated TEMPLATE_DECL. Otherwise, the original
6984 DECL is returned.
6986 Also handle the case when DECL is a TREE_LIST of ambiguous
6987 injected-class-names from different bases. */
6989 tree
6991 {
6995 /* DR 176: A lookup that finds an injected-class-name (10.2
6996 [class.member.lookup]) can result in an ambiguity in certain cases
6997 (for example, if it is found in more than one base class). If all of
6998 the injected-class-names that are found refer to specializations of
6999 the same class template, and if the name is followed by a
7000 template-argument-list, the reference refers to the class template
7001 itself and not a specialization thereof, and is not ambiguous. */
7003 {
7006 {
7012 }
7015 else
7017 }
7023 }
7025 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
7026 parameters, find the desired type.
7028 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
7030 IN_DECL, if non-NULL, is the template declaration we are trying to
7031 instantiate.
7033 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
7034 the class we are looking up.
7036 Issue error and warning messages under control of COMPLAIN.
7038 If the template class is really a local class in a template
7039 function, then the FUNCTION_CONTEXT is the function in which it is
7040 being instantiated.
7042 ??? Note that this function is currently called *twice* for each
7043 template-id: the first time from the parser, while creating the
7044 incomplete type (finish_template_type), and the second type during the
7045 real instantiation (instantiate_template_class). This is surely something
7046 that we want to avoid. It also causes some problems with argument
7047 coercion (see convert_nontype_argument for more information on this). */
7049 static tree
7052 {
7054 tree t;
7057 spec_entry elt;
7058 hashval_t hash;
7061 {
7065 else
7066 {
7073 }
7076 }
7078 {
7081 /* If we are declaring a constructor, say A<T>::A<T>, we will get
7082 an implicit typename for the second A. Deal with it. */
7087 {
7090 }
7091 }
7094 {
7097 }
7101 {
7105 }
7107 {
7110 }
7112 /* Issue an error message if we didn't find a template. */
7114 {
7118 }
7121 /* Make sure it's a user visible template, if it was named by
7122 the user. */
7125 {
7127 {
7131 }
7133 }
7138 {
7139 /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store
7140 template arguments */
7142 tree parm;
7143 tree arglist2;
7144 tree outer;
7148 /* Consider an example where a template template parameter declared as
7150 template <class T, class U = std::allocator<T> > class TT
7152 The template parameter level of T and U are one level larger than
7153 of TT. To proper process the default argument of U, say when an
7154 instantiation `TT<int>' is seen, we need to build the full
7155 arguments containing {int} as the innermost level. Outer levels,
7156 available when not appearing as default template argument, can be
7157 obtained from the arguments of the enclosing template.
7159 Suppose that TT is later substituted with std::vector. The above
7160 instantiation is `TT<int, std::allocator<T> >' with TT at
7161 level 1, and T at level 2, while the template arguments at level 1
7162 becomes {std::vector} and the inner level 2 is {int}. */
7168 /* This is an argument of the current template, so we haven't set
7169 DECL_CONTEXT yet. */
7176 complain,
7186 }
7187 else
7188 {
7190 tree gen_tmpl;
7191 tree type_decl;
7199 /* An error occured while building the template TEMPL, and a
7200 diagnostic has most certainly been emitted for that
7201 already. Let's propagate that error. */
7210 {
7211 /* We've been given an incomplete set of template arguments.
7212 For example, given:
7214 template <class T> struct S1 {
7215 template <class U> struct S2 {};
7216 template <class U> struct S2<U*> {};
7217 };
7219 we will be called with an ARGLIST of `U*', but the
7220 TEMPLATE will be `template <class T> template
7221 <class U> struct S1<T>::S2'. We must fill in the missing
7222 arguments. */
7223 arglist
7225 arglist);
7227 }
7229 /* Now we should have enough arguments. */
7232 /* From here on, we're only interested in the most general
7233 template. */
7235 /* Calculate the BOUND_ARGS. These will be the args that are
7236 actually tsubst'd into the definition to create the
7237 instantiation. */
7239 {
7240 /* We have multiple levels of arguments to coerce, at once. */
7250 {
7251 tree a;
7255 complain,
7258 else
7259 /* Outer levels should have already been coerced. */
7262 /* Don't process further if one of the levels fails. */
7264 {
7265 /* Restore the ARGLIST to its full size. */
7268 }
7272 /* We temporarily reduce the length of the ARGLIST so
7273 that coerce_template_parms will see only the arguments
7274 corresponding to the template parameters it is
7275 examining. */
7277 }
7279 /* Restore the ARGLIST to its full size. */
7283 }
7284 else
7285 arglist
7288 gen_tmpl,
7289 complain,
7294 /* We were unable to bind the arguments. */
7297 /* In the scope of a template class, explicit references to the
7298 template class refer to the type of the template, not any
7299 instantiation of it. For example, in:
7301 template <class T> class C { void f(C<T>); }
7303 the `C<T>' is just the same as `C'. Outside of the
7304 class, however, such a reference is an instantiation. */
7308 /* comp_template_args is expensive, check it last. */
7310 arglist))
7313 /* If we already have this specialization, return it. */
7325 /* If the deduced arguments are invalid, then the binding
7326 failed. */
7330 complain))
7337 {
7342 }
7352 /* Create the type. */
7354 {
7356 {
7362 }
7363 else
7364 {
7365 /* We don't want to call start_enum for this type, since
7366 the values for the enumeration constants may involve
7367 template parameters. And, no one should be interested
7368 in the enumeration constants for such a type. */
7371 }
7375 }
7377 {
7378 /* The user referred to a specialization of an alias
7379 template represented by GEN_TMPL.
7381 [temp.alias]/2 says:
7383 When a template-id refers to the specialization of an
7384 alias template, it is equivalent to the associated
7385 type obtained by substitution of its
7386 template-arguments for the template-parameters in the
7387 type-id of the alias template. */
7390 /* Note that the call above (by indirectly calling
7391 register_specialization in tsubst_decl) registers the
7392 TYPE_DECL representing the specialization of the alias
7393 template. So next time someone substitutes ARGLIST for
7394 the template parms into the alias template (GEN_TMPL),
7395 she'll get that TYPE_DECL back. */
7399 }
7401 {
7408 /* A local class. Make sure the decl gets registered properly. */
7413 /* This instantiation is another name for the primary
7414 template type. Set the TYPE_CANONICAL field
7415 appropriately. */
7418 /* Some of the template arguments require structural
7419 equality testing, so this template class requires
7420 structural equality testing. */
7422 }
7423 else
7426 /* If we called start_enum or pushtag above, this information
7427 will already be set up. */
7429 {
7436 }
7437 else
7441 {
7447 {
7450 }
7451 }
7453 /* Let's consider the explicit specialization of a member
7454 of a class template specialization that is implicitely instantiated,
7455 e.g.:
7456 template<class T>
7457 struct S
7458 {
7459 template<class U> struct M {}; //#0
7460 };
7462 template<>
7463 template<>
7464 struct S<int>::M<char> //#1
7465 {
7466 int i;
7467 };
7468 [temp.expl.spec]/4 says this is valid.
7470 In this case, when we write:
7471 S<int>::M<char> m;
7473 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
7474 the one of #0.
7476 When we encounter #1, we want to store the partial instantiation
7477 of M (template<class T> S<int>::M<T>) in it's CLASSTYPE_TI_TEMPLATE.
7479 For all cases other than this "explicit specialization of member of a
7480 class template", we just want to store the most general template into
7481 the CLASSTYPE_TI_TEMPLATE of M.
7483 This case of "explicit specialization of member of a class template"
7484 only happens when:
7485 1/ the enclosing class is an instantiation of, and therefore not
7486 the same as, the context of the most general template, and
7487 2/ we aren't looking at the partial instantiation itself, i.e.
7488 the innermost arguments are not the same as the innermost parms of
7489 the most general template.
7491 So it's only when 1/ and 2/ happens that we want to use the partial
7492 instantiation of the member template in lieu of its most general
7493 template. */
7497 /* the enclosing class must be an instantiation... */
7500 {
7501 tree partial_inst_args;
7504 partial_inst_args =
7510 use_partial_inst_tmpl =
7511 /*...and we must not be looking at the partial instantiation
7512 itself. */
7514 partial_inst_args);
7515 }
7518 /* This case is easy; there are no member templates involved. */
7520 else
7521 {
7522 /* This is a full instantiation of a member template. Find
7523 the partial instantiation of which this is an instance. */
7525 /* Temporarily reduce by one the number of levels in the ARGLIST
7526 so as to avoid comparing the last set of arguments. */
7530 /* FOUND is either a proper class type, or an alias
7531 template specialization. In the later case, it's a
7532 TYPE_DECL, resulting from the substituting of arguments
7533 for parameters in the TYPE_DECL of the alias template
7534 done earlier. So be careful while getting the template
7535 of FOUND. */
7539 }
7550 /* Note this use of the partial instantiation so we can check it
7551 later in maybe_process_partial_specialization. */
7557 /* Now that the type has been registered on the instantiations
7558 list, we set up the enumerators. Because the enumeration
7559 constants may involve the enumeration type itself, we make
7560 sure to register the type first, and then create the
7561 constants. That way, doing tsubst_expr for the enumeration
7562 constants won't result in recursive calls here; we'll find
7563 the instantiation and exit above. */
7567 /* If the type makes use of template parameters, the
7568 code that generates debugging information will crash. */
7571 /* Possibly limit visibility based on template args. */
7576 }
7577 }
7579 /* Wrapper for lookup_template_class_1. */
7581 tree
7584 {
7585 tree ret;
7591 }
7592 \f
7593 struct pair_fn_data
7594 {
7595 tree_fn_t fn;
7597 /* True when we should also visit template parameters that occur in
7598 non-deduced contexts. */
7601 };
7603 /* Called from for_each_template_parm via walk_tree. */
7605 static tree
7607 {
7620 {
7624 /* Fall through. */
7647 /* Since we're not going to walk subtrees, we have to do this
7648 explicitly here. */
7652 /* Fall through. */
7655 /* Check the return type. */
7660 /* Check the parameter types. Since default arguments are not
7661 instantiated until they are needed, the TYPE_ARG_TYPES may
7662 contain expressions that involve template parameters. But,
7663 no-one should be looking at them yet. And, once they're
7664 instantiated, they don't contain template parameters, so
7665 there's no point in looking at them then, either. */
7666 {
7667 tree parm;
7674 /* Since we've already handled the TYPE_ARG_TYPES, we don't
7675 want walk_tree walking into them itself. */
7677 }
7695 /* Fall through. */
7711 /* Record template parameters such as `T' inside `TT<T>'. */
7715 /* Fall through. */
7727 /* A template template parameter is encountered. */
7733 /* Already substituted template template parameter */
7756 /* If there's no type, then this thing must be some expression
7757 involving template parameters. */
7779 }
7781 /* We didn't find any template parameters we liked. */
7783 }
7785 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
7786 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
7787 call FN with the parameter and the DATA.
7788 If FN returns nonzero, the iteration is terminated, and
7789 for_each_template_parm returns 1. Otherwise, the iteration
7790 continues. If FN never returns a nonzero value, the value
7791 returned by for_each_template_parm is 0. If FN is NULL, it is
7792 considered to be the function which always returns 1.
7794 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
7795 parameters that occur in non-deduced contexts. When false, only
7796 visits those template parameters that can be deduced. */
7798 static int
7802 {
7806 /* Set up. */
7811 /* Walk the tree. (Conceptually, we would like to walk without
7812 duplicates, but for_each_template_parm_r recursively calls
7813 for_each_template_parm, so we would need to reorganize a fair
7814 bit to use walk_tree_without_duplicates, so we keep our own
7815 visited list.) */
7818 else
7821 for_each_template_parm_r,
7825 /* Clean up. */
7827 {
7830 }
7833 }
7835 /* Returns true if T depends on any template parameter. */
7837 int
7839 {
7866 else
7867 {
7870 }
7875 }
7877 /* Returns true iff current_function_decl is an incompletely instantiated
7878 template. Useful instead of processing_template_decl because the latter
7879 is set to 0 during fold_non_dependent_expr. */
7881 bool
7883 {
7892 }
7894 /* Returns true if T depends on any template parameter with level LEVEL. */
7896 int
7898 {
7901 }
7903 /* Returns TRUE iff INST is an instantiation we don't need to do in an
7904 ill-formed translation unit, i.e. a variable or function that isn't
7905 usable in a constant expression. */
7909 {
7913 }
7915 /* Returns TRUE iff we should refuse to instantiate DECL because it's
7916 neglectable and instantiated from within an erroneous instantiation. */
7918 static bool
7920 {
7931 }
7939 /* We're starting to instantiate D; record the template instantiation context
7940 for diagnostics and to restore it later. */
7942 int
7944 {
7948 {
7954 else
7962 }
7964 /* If the current instantiation caused problems, don't let it instantiate
7965 anything else. Do allow deduction substitution and decls usable in
7966 constant expressions. */
7983 }
7985 /* We're done instantiating this template; return to the instantiation
7986 context. */
7988 void
7990 {
7991 /* Restore the filename and line number stashed away when we started
7992 this instantiation. */
7996 }
7998 /* We're instantiating a deferred template; restore the template
7999 instantiation context in which the instantiation was requested, which
8000 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
8002 static tree
8004 {
8016 }
8018 /* Returns the TINST_LEVEL which gives the original instantiation
8019 context. */
8023 {
8029 }
8031 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
8032 vector of template arguments, as for tsubst.
8034 Returns an appropriate tsubst'd friend declaration. */
8036 static tree
8038 {
8039 tree new_friend;
8044 /* This was a friend declared with an explicit template
8045 argument list, e.g.:
8047 friend void f<>(T);
8049 to indicate that f was a template instantiation, not a new
8050 function declaration. Now, we have to figure out what
8051 instantiation of what template. */
8052 {
8054 tree new_args;
8055 tree tmpl;
8058 /* Friend functions are looked up in the containing namespace scope.
8059 We must enter that scope, to avoid finding member functions of the
8060 current class with same name. */
8075 tsk_none);
8077 }
8081 /* The NEW_FRIEND will look like an instantiation, to the
8082 compiler, but is not an instantiation from the point of view of
8083 the language. For example, we might have had:
8085 template <class T> struct S {
8086 template <class U> friend void f(T, U);
8087 };
8089 Then, in S<int>, template <class U> void f(int, U) is not an
8090 instantiation of anything. */
8096 {
8100 }
8102 /* The mangled name for the NEW_FRIEND is incorrect. The function
8103 is not a template instantiation and should not be mangled like
8104 one. Therefore, we forget the mangling here; we'll recompute it
8105 later if we need it. */
8107 {
8110 }
8113 {
8114 tree old_decl;
8115 tree new_friend_template_info;
8116 tree new_friend_result_template_info;
8117 tree ns;
8120 /* We must save some information from NEW_FRIEND before calling
8121 duplicate decls since that function will free NEW_FRIEND if
8122 possible. */
8124 new_friend_is_defn =
8129 {
8130 /* This declaration is a `primary' template. */
8133 new_friend_result_template_info
8135 }
8136 else
8139 /* Make the init_value nonzero so pushdecl knows this is a defn. */
8143 /* Inside pushdecl_namespace_level, we will push into the
8144 current namespace. However, the friend function should go
8145 into the namespace of the template. */
8155 {
8156 /* This new friend declaration matched an existing
8157 declaration. For example, given:
8159 template <class T> void f(T);
8160 template <class U> class C {
8161 template <class T> friend void f(T) {}
8162 };
8164 the friend declaration actually provides the definition
8165 of `f', once C has been instantiated for some type. So,
8166 old_decl will be the out-of-class template declaration,
8167 while new_friend is the in-class definition.
8169 But, if `f' was called before this point, the
8170 instantiation of `f' will have DECL_TI_ARGS corresponding
8171 to `T' but not to `U', references to which might appear
8172 in the definition of `f'. Previously, the most general
8173 template for an instantiation of `f' was the out-of-class
8174 version; now it is the in-class version. Therefore, we
8175 run through all specialization of `f', adding to their
8176 DECL_TI_ARGS appropriately. In particular, they need a
8177 new set of outer arguments, corresponding to the
8178 arguments for this class instantiation.
8180 The same situation can arise with something like this:
8182 friend void f(int);
8183 template <class T> class C {
8184 friend void f(T) {}
8185 };
8187 when `C<int>' is instantiated. Now, `f(int)' is defined
8188 in the class. */
8191 /* On the other hand, if the in-class declaration does
8192 *not* provide a definition, then we don't want to alter
8193 existing definitions. We can just leave everything
8194 alone. */
8195 ;
8196 else
8197 {
8201 /* Overwrite whatever template info was there before, if
8202 any, with the new template information pertaining to
8203 the declaration. */
8207 {
8208 /* We should have called reregister_specialization in
8209 duplicate_decls. */
8214 /* Instantiate it if the global has already been used. */
8218 }
8219 else
8220 {
8221 tree t;
8223 /* Indicate that the old function template is a partial
8224 instantiation. */
8232 /* Reassign any specializations already in the hash table
8233 to the new more general template, and add the
8234 additional template args. */
8238 {
8240 spec_entry elt;
8252 register_specialization
8255 }
8257 }
8258 }
8260 /* The information from NEW_FRIEND has been merged into OLD_DECL
8261 by duplicate_decls. */
8263 }
8264 }
8265 else
8266 {
8270 /* In the code
8271 template <class T> class C {
8272 template <class U> friend void C1<U>::f (); // case 1
8273 friend void C2<T>::f (); // case 2
8274 };
8275 we only need to make sure CONTEXT is a complete type for
8276 case 2. To distinguish between the two cases, we note that
8277 CONTEXT of case 1 remains dependent type after tsubst while
8278 this isn't true for case 2. */
8288 {
8289 /* Check to see that the declaration is really present, and,
8290 possibly obtain an improved declaration. */
8296 }
8297 }
8300 }
8302 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
8303 template arguments, as for tsubst.
8305 Returns an appropriate tsubst'd friend type or error_mark_node on
8306 failure. */
8308 static tree
8310 {
8311 tree friend_type;
8312 tree tmpl;
8313 tree context;
8316 {
8319 }
8324 {
8327 else
8329 }
8331 /* Look for a class template declaration. We look for hidden names
8332 because two friend declarations of the same template are the
8333 same. For example, in:
8335 struct A {
8336 template <typename> friend class F;
8337 };
8338 template <typename> struct B {
8339 template <typename> friend class F;
8340 };
8342 both F templates are the same. */
8346 /* But, if we don't find one, it might be because we're in a
8347 situation like this:
8349 template <class T>
8350 struct S {
8351 template <class U>
8352 friend struct S;
8353 };
8355 Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL
8356 for `S<int>', not the TEMPLATE_DECL. */
8358 {
8361 }
8364 {
8365 /* The friend template has already been declared. Just
8366 check to see that the declarations match, and install any new
8367 default parameters. We must tsubst the default parameters,
8368 of course. We only need the innermost template parameters
8369 because that is all that redeclare_class_template will look
8370 at. */
8373 {
8374 tree parms;
8375 location_t saved_input_location;
8384 }
8387 }
8388 else
8389 {
8390 /* The friend template has not already been declared. In this
8391 case, the instantiation of the template class will cause the
8392 injection of this template into the global scope. */
8397 /* The new TMPL is not an instantiation of anything, so we
8398 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for
8399 the new type because that is supposed to be the corresponding
8400 template decl, i.e., TMPL. */
8407 /* Inject this template into the global scope. */
8409 }
8412 {
8415 else
8417 }
8420 }
8422 /* Returns zero if TYPE cannot be completed later due to circularity.
8423 Otherwise returns one. */
8425 static int
8427 {
8437 else
8439 }
8441 /* Apply any attributes which had to be deferred until instantiation
8442 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
8443 ARGS, COMPLAIN, IN_DECL are as tsubst. */
8445 static void
8448 {
8450 tree t;
8455 {
8459 }
8462 {
8466 }
8467 else
8471 {
8476 {
8479 {
8482 /* If the first attribute argument is an identifier, don't
8483 pass it through tsubst. Attributes like mode, format,
8484 cleanup and several target specific attributes expect it
8485 unmodified. */
8491 {
8492 tree chain
8494 in_decl,
8499 chain);
8500 }
8501 else
8507 }
8508 else
8510 }
8513 }
8514 }
8516 /* Perform (or defer) access check for typedefs that were referenced
8517 from within the template TMPL code.
8518 This is a subroutine of instantiate_decl and instantiate_class_template.
8519 TMPL is the template to consider and TARGS is the list of arguments of
8520 that template. */
8522 static void
8524 {
8525 location_t saved_location;
8536 {
8548 /* Make access check error messages point to the location
8549 of the use of the typedef. */
8553 tf_warning_or_error);
8554 }
8556 }
8558 static tree
8560 {
8562 tree typedecl;
8563 tree pbinfo;
8564 tree base_list;
8566 tree fn_context;
8575 /* Figure out which template is being instantiated. */
8579 /* Determine what specialization of the original template to
8580 instantiate. */
8583 {
8586 }
8588 {
8589 /* This TYPE is actually an instantiation of a partial
8590 specialization. We replace the innermost set of ARGS with
8591 the arguments appropriate for substitution. For example,
8592 given:
8594 template <class T> struct S {};
8595 template <class T> struct S<T*> {};
8597 and supposing that we are instantiating S<int*>, ARGS will
8598 presently be {int*} -- but we need {int}. */
8601 }
8602 else
8603 {
8606 }
8608 /* If the template we're instantiating is incomplete, then clearly
8609 there's nothing we can do. */
8613 /* If we've recursively instantiated too many templates, stop. */
8617 /* Now we're really doing the instantiation. Mark the type as in
8618 the process of being defined. */
8621 /* We may be in the middle of deferred access check. Disable
8622 it now. */
8628 /* Use #pragma pack from the template context. */
8634 /* Set the input location to the most specialized template definition.
8635 This is needed if tsubsting causes an error. */
8647 {
8650 /* Adjust visibility for template arguments. */
8652 }
8657 /* We should never instantiate a nested class before its enclosing
8658 class; we need to look up the nested class by name before we can
8659 instantiate it, and that lookup should instantiate the enclosing
8660 class. */
8666 {
8667 tree pbase_binfo;
8668 tree pushed_scope;
8671 /* We must enter the scope containing the type, as that is where
8672 the accessibility of types named in dependent bases are
8673 looked up from. */
8676 /* Substitute into each of the bases to determine the actual
8677 basetypes. */
8679 {
8680 tree base;
8686 {
8687 expanded_bases =
8694 }
8697 {
8699 /* Extract the already-expanded base class. */
8701 else
8702 /* Substitute to figure out the base class. */
8704 NULL_TREE);
8712 }
8713 }
8715 /* The list is now in reverse order; correct that. */
8720 }
8721 /* Now call xref_basetypes to set up all the base-class
8722 information. */
8730 /* Now that our base classes are set up, enter the scope of the
8731 class, so that name lookups into base classes, etc. will work
8732 correctly. This is precisely analogous to what we do in
8733 begin_class_definition when defining an ordinary non-template
8734 class, except we also need to push the enclosing classes. */
8737 /* Now members are processed in the order of declaration. */
8740 {
8744 {
8746 {
8747 /* Build new CLASSTYPE_NESTED_UTDS. */
8749 tree newtag;
8755 /* If the member is a class template, then -- even after
8756 substitution -- there may be dependent types in the
8757 template argument list for the class. We increment
8758 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
8759 that function will assume that no types are dependent
8760 when outside of a template. */
8770 {
8774 /* Unfortunately, lookup_template_class sets
8775 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
8776 instantiation (i.e., for the type of a member
8777 template class nested within a template class.)
8778 This behavior is required for
8779 maybe_process_partial_specialization to work
8780 correctly, but is not accurate in this case;
8781 the TAG is not an instantiation of anything.
8782 (The corresponding TEMPLATE_DECL is an
8783 instantiation, but the TYPE is not.) */
8786 /* Now, we call pushtag to put this NEWTAG into the scope of
8787 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
8788 pushtag calling push_template_decl. We don't have to do
8789 this for enums because it will already have been done in
8790 tsubst_enum. */
8794 }
8795 }
8798 {
8799 /* Build new TYPE_METHODS. */
8800 tree r;
8809 /* Instantiate members marked with attribute used. */
8812 }
8813 else
8814 {
8815 /* Build new TYPE_FIELDS. */
8817 {
8818 tree condition;
8821 condition =
8831 }
8833 {
8834 tree r;
8836 /* The file and line for this declaration, to
8837 assist in error message reporting. Since we
8838 called push_tinst_level above, we don't need to
8839 restore these. */
8848 {
8849 /* In [temp.inst]:
8851 [t]he initialization (and any associated
8852 side-effects) of a static data member does
8853 not occur unless the static data member is
8854 itself used in a way that requires the
8855 definition of the static data member to
8856 exist.
8858 Therefore, we do not substitute into the
8859 initialized for the static data member here. */
8860 finish_static_data_member_decl
8866 /* Instantiate members marked with attribute used. */
8869 }
8871 {
8872 /* Determine whether R has a valid type and can be
8873 completed later. If R is invalid, then it is
8874 replaced by error_mark_node so that it will not be
8875 added to TYPE_FIELDS. */
8881 {
8884 }
8885 }
8887 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
8888 such a thing will already have been added to the field
8889 list by tsubst_enum in finish_member_declaration in the
8890 CLASSTYPE_NESTED_UTDS case above. */
8894 {
8897 }
8898 }
8899 }
8900 }
8901 else
8902 {
8905 {
8906 /* Build new CLASSTYPE_FRIEND_CLASSES. */
8912 {
8913 /* template <class T> friend class C; */
8916 }
8918 {
8919 /* template <class T> friend class C::D; */
8925 }
8928 {
8929 /* This could be either
8931 friend class T::C;
8933 when dependent_type_p is false or
8935 template <class U> friend class T::C;
8937 otherwise. */
8940 /* Bump processing_template_decl for correct
8941 dependent_type_p calculation. */
8946 }
8949 {
8950 /* friend class C;
8952 where C hasn't been declared yet. Let's lookup name
8953 from namespace scope directly, bypassing any name that
8954 come from dependent base class. */
8957 /* The call to xref_tag_from_type does injection for friend
8958 classes. */
8960 friend_type =
8964 }
8966 /* friend class C<T>; */
8969 /* Otherwise it's
8971 friend class C;
8973 where C is already declared or
8975 friend class C<int>;
8977 We don't have to do anything in these cases. */
8980 /* Trick make_friend_class into realizing that the friend
8981 we're adding is a template, not an ordinary class. It's
8982 important that we use make_friend_class since it will
8983 perform some error-checking and output cross-reference
8984 information. */
8992 }
8993 else
8994 {
8995 /* Build new DECL_FRIENDLIST. */
8996 tree r;
8998 /* The file and line for this declaration, to
8999 assist in error message reporting. Since we
9000 called push_tinst_level above, we don't need to
9001 restore these. */
9005 {
9008 }
9013 {
9016 }
9017 }
9018 }
9019 }
9022 {
9025 {
9028 /* We need to instantiate the capture list from the template
9029 after we've instantiated the closure members, but before we
9030 consider adding the conversion op. Also keep any captures
9031 that may have been added during instantiation of the op(). */
9033 tree tmpl_cap
9042 }
9043 else
9045 }
9047 /* Set the file and line number information to whatever is given for
9048 the class itself. This puts error messages involving generated
9049 implicit functions at a predictable point, and the same point
9050 that would be used for non-template classes. */
9057 /* We don't instantiate default arguments for member functions. 14.7.1:
9059 The implicit instantiation of a class template specialization causes
9060 the implicit instantiation of the declarations, but not of the
9061 definitions or default arguments, of the class member functions,
9062 member classes, static data members and member templates.... */
9064 /* Some typedefs referenced from within the template code need to be access
9065 checked at template instantiation time, i.e now. These types were
9066 added to the template at parsing time. Let's get those and perform
9067 the access checks then. */
9077 /* The vtable for a template class can be emitted in any translation
9078 unit in which the class is instantiated. When there is no key
9079 method, however, finish_struct_1 will already have added TYPE to
9080 the keyed_classes list. */
9085 }
9087 /* Wrapper for instantiate_class_template_1. */
9089 tree
9091 {
9092 tree ret;
9097 }
9099 static tree
9101 {
9102 tree r;
9108 else
9109 {
9116 }
9118 }
9120 /* Given a function parameter pack TMPL_PARM and some function parameters
9121 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
9122 and set *SPEC_P to point at the next point in the list. */
9124 static tree
9126 {
9127 /* Collect all of the extra "packed" parameters into an
9128 argument pack. */
9129 tree parmvec;
9130 tree parmtypevec;
9141 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
9146 {
9149 }
9151 /* Build the argument packs. */
9158 }
9160 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
9161 NONTYPE_ARGUMENT_PACK. */
9163 static tree
9165 {
9167 }
9169 /* Return true iff the Ith element of the argument pack ARG_PACK is a
9170 pack expansion. */
9172 static bool
9174 {
9179 }
9182 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
9184 static tree
9186 {
9193 }
9195 /* This is a subroutine of tsubst_pack_expansion.
9197 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
9198 mechanism to store the (non complete list of) arguments of the
9199 substitution and return a non substituted pack expansion, in order
9200 to wait for when we have enough arguments to really perform the
9201 substitution. */
9203 static bool
9207 {
9208 /* If one pack has an expansion and another pack has a normal
9209 argument or if one pack has an empty argument and an another
9210 one hasn't then tsubst_pack_expansion cannot perform the
9211 substitution and need to fall back on the
9212 PACK_EXPANSION_EXTRA mechanism. */
9220 {
9223 parm_pack;
9225 {
9230 else
9232 }
9236 }
9238 }
9240 /* [temp.variadic]/6 says that:
9242 The instantiation of a pack expansion [...]
9243 produces a list E1,E2, ..., En, where N is the number of elements
9244 in the pack expansion parameters.
9246 This subroutine of tsubst_pack_expansion produces one of these Ei.
9248 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
9249 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
9250 PATTERN, and each TREE_VALUE is its corresponding argument pack.
9251 INDEX is the index 'i' of the element Ei to produce. ARGS,
9252 COMPLAIN, and IN_DECL are the same parameters as for the
9253 tsubst_pack_expansion function.
9255 The function returns the resulting Ei upon successful completion,
9256 or error_mark_node.
9258 Note that this function possibly modifies the ARGS parameter, so
9259 it's the responsibility of the caller to restore it. */
9261 static tree
9263 tree parm_packs,
9265 tree args /* This parm gets
9267 tsubst_flags_t complain,
9268 tree in_decl)
9269 {
9270 tree t;
9273 /* For each parameter pack, change the substitution of the parameter
9274 pack to the ith argument in its argument pack, then expand the
9275 pattern. */
9277 {
9282 ith_elem_is_expansion |=
9285 /* Select the Ith argument from the pack. */
9287 {
9289 {
9293 }
9294 else
9296 }
9297 else
9298 {
9303 {
9305 /* Update the corresponding argument. */
9307 }
9308 else
9309 /* Re-use the ARGUMENT_PACK_SELECT. */
9311 }
9313 }
9315 /* Substitute into the PATTERN with the (possibly altered)
9316 arguments. */
9320 else
9323 /* If the Ith argument pack element is a pack expansion, then
9324 the Ith element resulting from the substituting is going to
9325 be a pack expansion as well. */
9330 }
9332 /* Substitute ARGS into T, which is an pack expansion
9333 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
9334 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
9335 (if only a partial substitution could be performed) or
9336 ERROR_MARK_NODE if there was an error. */
9337 tree
9339 tree in_decl)
9340 {
9341 tree pattern;
9345 tree result;
9353 /* Add in any args remembered from an earlier partial instantiation. */
9358 /* Determine the argument packs that will instantiate the parameter
9359 packs used in the expansion expression. While we're at it,
9360 compute the number of arguments to be expanded and make sure it
9361 is consistent. */
9364 {
9371 {
9375 else
9378 }
9380 {
9383 else
9384 {
9385 /* We can't rely on local_specializations for a parameter
9386 name used later in a function declaration (such as in a
9387 late-specified return type). Even if it exists, it might
9388 have the wrong value for a recursive call. Just make a
9389 dummy decl, since it's only used for its type. */
9392 /* Partial instantiation of the parm_pack, we can't build
9393 up an argument pack yet. */
9395 else
9398 }
9399 }
9400 else
9401 {
9407 }
9414 /* This can only happen if we forget to expand an argument
9415 pack somewhere else. Just return an error, silently. */
9416 {
9420 }
9423 {
9427 /* Don't bother trying to do a partial substitution with
9428 incomplete packs; we'll try again after deduction. */
9435 {
9441 pattern);
9442 else
9445 pattern);
9447 }
9449 /* Keep track of the parameter packs and their corresponding
9450 argument packs. */
9453 }
9454 else
9455 {
9456 /* We can't substitute for this parameter pack. We use a flag as
9457 well as the missing_level counter because function parameter
9458 packs don't have a level. */
9460 }
9461 }
9463 /* We cannot expand this expansion expression, because we don't have
9464 all of the argument packs we need. */
9466 {
9467 /* We got some full packs, but we can't substitute them in until we
9468 have values for all the packs. So remember these until then. */
9473 }
9475 {
9476 /* There were no real arguments, we're just replacing a parameter
9477 pack with another version of itself. Substitute into the
9478 pattern and return a PACK_EXPANSION_*. The caller will need to
9479 deal with that. */
9483 else
9487 }
9492 {
9493 /* We're in a late-specified return type, so create our own local
9494 specializations map; the current map is either NULL or (in the
9495 case of recursive unification) might have bindings that we don't
9496 want to use or alter. */
9499 }
9501 /* For each argument in each argument pack, substitute into the
9502 pattern. */
9505 {
9507 i,
9509 in_decl);
9512 {
9515 }
9516 }
9518 /* Update ARGS to restore the substitution from parameter packs to
9519 their argument packs. */
9521 {
9526 else
9527 {
9535 /* Update the corresponding argument. */
9539 else
9541 }
9542 }
9545 {
9548 }
9551 }
9553 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
9554 TMPL. We do this using DECL_PARM_INDEX, which should work even with
9555 parameter packs; all parms generated from a function parameter pack will
9556 have the same DECL_PARM_INDEX. */
9558 tree
9560 {
9562 tree patparm;
9565 {
9571 }
9572 else
9573 {
9578 }
9581 }
9583 /* Substitute ARGS into the vector or list of template arguments T. */
9585 static tree
9587 {
9599 {
9601 tree new_arg;
9606 {
9607 /* Substitute into an expansion expression. */
9611 /* Add to the expanded length adjustment the number of
9612 expanded arguments. We subtract one from this
9613 measurement, because the argument pack expression
9614 itself is already counted as 1 in
9615 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
9616 the argument pack is empty. */
9618 }
9620 {
9621 /* Substitute into each of the arguments. */
9627 new_arg,
9641 }
9642 }
9643 else
9652 }
9657 /* Make space for the expanded arguments coming from template
9658 argument packs. */
9660 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
9661 arguments for a member template.
9662 In that case each TREE_VEC in ORIG_T represents a level of template
9663 arguments, and ORIG_T won't carry any non defaulted argument count.
9664 It will rather be the nested TREE_VECs that will carry one.
9665 In other words, ORIG_T carries a non defaulted argument count only
9666 if it doesn't contain any nested TREE_VEC. */
9668 {
9672 }
9674 {
9678 {
9681 /* Now expand the template argument pack "in place". */
9684 }
9685 else
9686 {
9688 out++;
9689 }
9690 }
9693 }
9695 /* Return the result of substituting ARGS into the template parameters
9696 given by PARMS. If there are m levels of ARGS and m + n levels of
9697 PARMS, then the result will contain n levels of PARMS. For
9698 example, if PARMS is `template <class T> template <class U>
9699 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
9700 result will be `template <int*, double, class V>'. */
9702 static tree
9704 {
9708 /* When substituting into a template, we must set
9709 PROCESSING_TEMPLATE_DECL as the template parameters may be
9710 dependent if they are based on one-another, and the dependency
9711 predicates are short-circuit outside of templates. */
9718 {
9719 tree new_vec =
9724 {
9725 tree tuple;
9737 }
9743 }
9748 }
9750 /* Return the result of substituting ARGS into one template parameter
9751 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
9752 parameter and which TREE_PURPOSE is the default argument of the
9753 template parameter. */
9755 static tree
9757 {
9778 }
9780 /* Substitute the ARGS into the indicated aggregate (or enumeration)
9781 type T. If T is not an aggregate or enumeration type, it is
9782 handled as if by tsubst. IN_DECL is as for tsubst. If
9783 ENTERING_SCOPE is nonzero, T is the context for a template which
9784 we are presently tsubst'ing. Return the substituted value. */
9786 static tree
9788 tree args,
9789 tsubst_flags_t complain,
9790 tree in_decl,
9792 {
9797 {
9802 /* Else fall through. */
9806 {
9807 tree argvec;
9808 tree context;
9809 tree r;
9813 /* In "sizeof(X<I>)" we need to evaluate "I". */
9819 /* First, determine the context for the type we are looking
9820 up. */
9823 {
9826 /* If context is a nested class inside a class template,
9827 it may still need to be instantiated (c++/33959). */
9829 }
9831 /* Then, figure out what arguments are appropriate for the
9832 type we are trying to find. For example, given:
9834 template <class T> struct S;
9835 template <class T, class U> void f(T, U) { S<U> su; }
9837 and supposing that we are instantiating f<int, double>,
9838 then our ARGS will be {int, double}, but, when looking up
9839 S we only want {double}. */
9844 else
9845 {
9849 }
9855 }
9856 else
9857 /* This is not a template type, so there's nothing to do. */
9862 }
9863 }
9865 /* Substitute into the default argument ARG (a default argument for
9866 FN), which has the indicated TYPE. */
9868 tree
9870 {
9875 /* This can happen in invalid code. */
9879 /* This default argument came from a template. Instantiate the
9880 default argument here, not in tsubst. In the case of
9881 something like:
9883 template <class T>
9884 struct S {
9885 static T t();
9886 void f(T = t());
9887 };
9889 we must be careful to do name lookup in the scope of S<T>,
9890 rather than in the current class. */
9892 /* The "this" pointer is not valid in a default argument. */
9894 {
9899 }
9902 /* The default argument expression may cause implicitly defined
9903 member functions to be synthesized, which will result in garbage
9904 collection. We must treat this situation as if we were within
9905 the body of function so as to avoid collecting live data on the
9906 stack. */
9914 /* Restore the "this" pointer. */
9916 {
9919 }
9926 /* Make sure the default argument is reasonable. */
9932 }
9934 /* Substitute into all the default arguments for FN. */
9936 static void
9938 {
9939 tree arg;
9940 tree tmpl_args;
9944 /* If this function is not yet instantiated, we certainly don't need
9945 its default arguments. */
9948 /* Don't do this again for clones. */
9953 arg;
9959 complain);
9960 }
9962 /* Substitute the ARGS into the T, which is a _DECL. Return the
9963 result of the substitution. Issue error and warning messages under
9964 control of COMPLAIN. */
9966 static tree
9968 {
9969 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
9970 location_t saved_loc;
9975 /* Set the filename and linenumber to improve error-reporting. */
9980 {
9982 {
9983 /* We can get here when processing a member function template,
9984 member class template, or template template parameter. */
9986 tree spec;
9987 tree tmpl_args;
9988 tree full_args;
9991 {
9992 /* Template template parameter is treated here. */
9996 /* If we get a real template back, return it. This can happen in
9997 the context of most_specialized_class. */
10009 complain);
10012 }
10014 /* We might already have an instance of this template.
10015 The ARGS are for the surrounding class type, so the
10016 full args contain the tsubst'd args for the context,
10017 plus the innermost args from the template decl. */
10021 /* Because this is a template, the arguments will still be
10022 dependent, even after substitution. If
10023 PROCESSING_TEMPLATE_DECL is not set, the dependency
10024 predicates will short-circuit. */
10032 /* If this is a default template template argument,
10033 tsubst might not have changed anything. */
10040 {
10043 }
10045 /* Make a new template decl. It will be similar to the
10046 original, but will record the current template arguments.
10047 We also create a new function declaration, which is just
10048 like the old one, but points to this new template, rather
10049 than the old one. */
10058 {
10059 tree new_type;
10071 }
10072 else
10073 {
10074 tree new_decl;
10086 }
10092 /* The template parameters for this new template are all the
10093 template parameters for the old template, except the
10094 outermost level of parameters. */
10097 complain);
10103 /* Record this non-type partial instantiation. */
10107 }
10111 {
10112 tree ctx;
10115 tree gen_tmpl;
10116 tree type;
10121 /* Nobody should be tsubst'ing into non-template functions. */
10125 {
10126 tree spec;
10129 /* If T is not dependent, just return it. We have to
10130 increment PROCESSING_TEMPLATE_DECL because
10131 value_dependent_expression_p assumes that nothing is
10132 dependent when PROCESSING_TEMPLATE_DECL is zero. */
10139 /* Calculate the most general template of which R is a
10140 specialization, and the complete set of arguments used to
10141 specialize R. */
10144 (DECL_TEMPLATE_RESULT
10150 /* Check to see if we already have this specialization. */
10155 {
10158 }
10160 /* We can see more levels of arguments than parameters if
10161 there was a specialization of a member template, like
10162 this:
10164 template <class T> struct S { template <class U> void f(); }
10165 template <> template <class U> void S<int>::f(U);
10167 Here, we'll be substituting into the specialization,
10168 because that's where we can find the code we actually
10169 want to generate, but we'll have enough arguments for
10170 the most general template.
10172 We also deal with the peculiar case:
10174 template <class T> struct S {
10175 template <class U> friend void f();
10176 };
10177 template <class U> void f() {}
10178 template S<int>;
10179 template void f<double>();
10181 Here, the ARGS for the instantiation of will be {int,
10182 double}. But, we only need as many ARGS as there are
10183 levels of template parameters in CODE_PATTERN. We are
10184 careful not to get fooled into reducing the ARGS in
10185 situations like:
10187 template <class T> struct S { template <class U> void f(U); }
10188 template <class T> template <> void S<T>::f(int) {}
10190 which we can spot because the pattern will be a
10191 specialization in this case. */
10193 parms_depth =
10198 }
10199 else
10200 {
10201 /* This special case arises when we have something like this:
10203 template <class T> struct S {
10204 friend void f<int>(int, double);
10205 };
10207 Here, the DECL_TI_TEMPLATE for the friend declaration
10208 will be an IDENTIFIER_NODE. We are being called from
10209 tsubst_friend_function, and we want only to create a
10210 new decl (R) with appropriate types so that we can call
10211 determine_specialization. */
10213 }
10216 {
10219 else
10223 }
10224 else
10225 {
10228 }
10233 /* If we hit excessive deduction depth, the type is bogus even if
10234 it isn't error_mark_node, so don't build a decl. */
10238 /* We do NOT check for matching decls pushed separately at this
10239 point, as they may not represent instantiations of this
10240 template, and in any case are considered separate under the
10241 discrete model. */
10245 /* Clear out the mangled name and RTL for the instantiation. */
10248 /* Leave DECL_INITIAL set on deleted instantiations. */
10254 /* Type-conversion operator. Reconstruct the name, in
10255 case it's the name of one of the template's parameters. */
10265 /* If this is an instantiation of a function with internal
10266 linkage, we already know what object file linkage will be
10267 assigned to the instantiation. */
10276 /* We'll re-clone as appropriate in instantiate_template. */
10279 /* If we aren't complaining now, return on error before we register
10280 the specialization so that we'll complain eventually. */
10286 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
10287 this in the special friend case mentioned above where
10288 GEN_TMPL is NULL. */
10290 {
10296 /* We're not supposed to instantiate default arguments
10297 until they are called, for a template. But, for a
10298 declaration like:
10300 template <class T> void f ()
10301 { extern void g(int i = T()); }
10303 we should do the substitution when the template is
10304 instantiated. We handle the member function case in
10305 instantiate_class_template since the default arguments
10306 might refer to other members of the class. */
10311 }
10312 else
10315 /* Copy the list of befriending classes. */
10319 {
10323 in_decl);
10324 }
10327 {
10333 /* If this is an instantiation of a member template, clone it.
10334 If it isn't, that'll be handled by
10335 clone_constructors_and_destructors. */
10338 }
10349 /* Possibly limit visibility based on template args. */
10352 {
10356 }
10364 }
10368 {
10376 {
10377 /* If there is a local specialization that isn't a
10378 parameter pack, it means that we're doing a "simple"
10379 substitution from inside tsubst_pack_expansion. Just
10380 return the local specialization (which will be a single
10381 parm). */
10388 /* Expand the TYPE_PACK_EXPANSION that provides the types for
10389 the parameters in this function parameter pack. */
10393 {
10396 /* Zero-length parameter packs are boring. Just substitute
10397 into the chain. */
10401 }
10402 else
10403 {
10404 /* All we did was update the type. Make a note of that. */
10407 }
10408 }
10410 /* Loop through all of the parameter's we'll build. When T is
10411 a function parameter pack, LEN is the number of expanded
10412 types in EXPANDED_TYPES; otherwise, LEN is 1. */
10415 {
10422 /* We're on the Ith parameter of the function parameter
10423 pack. */
10424 {
10425 /* An argument of a function parameter pack is not a parameter
10426 pack. */
10429 /* Get the Ith type. */
10432 /* Rename the parameter to include the index. */
10435 }
10437 /* We're dealing with a normal parameter. */
10445 {
10448 else
10451 }
10461 /* Keep track of the first new parameter we
10462 generate. That's what will be returned to the
10463 caller. */
10467 /* Build a proper chain of parameters when substituting
10468 into a function parameter pack. */
10471 }
10473 /* If cp_unevaluated_operand is set, we're just looking for a
10474 single dummy parameter, so don't keep going. */
10479 /* FIRST_R contains the start of the chain we've built. */
10481 }
10485 {
10486 tree type;
10496 /* For bit-fields, DECL_INITIAL gives the number of bits. For
10497 non-bit-fields DECL_INITIAL is a non-static data member
10498 initializer, which gets deferred instantiation. */
10504 {
10505 /* Set up DECL_TEMPLATE_INFO so that we can get at the
10506 NSDMI in perform_member_init. Still set DECL_INITIAL
10507 so that we know there is one. */
10512 }
10513 /* We don't have to set DECL_CONTEXT here; it is set by
10514 finish_member_declaration. */
10521 }
10525 /* We reach here only for member using decls. We also need to check
10526 uses_template_parms because DECL_DEPENDENT_P is not set for a
10527 using-declaration that designates a member of the current
10528 instantiation (c++/53549). */
10531 {
10538 else
10539 {
10542 }
10543 }
10544 else
10545 {
10548 }
10553 {
10556 tree spec;
10558 tree ctx;
10564 {
10565 /* If this is the canonical decl, we don't have to
10566 mess with instantiations, and often we can't (for
10567 typename, template type parms and such). Note that
10568 TYPE_NAME is not correct for the above test if
10569 we've copied the type for a typedef. */
10575 }
10577 /* Check to see if we already have the specialization we
10578 need. */
10581 {
10582 /* T is a static data member or namespace-scope entity.
10583 We have to substitute into namespace-scope variables
10584 (even though such entities are never templates) because
10585 of cases like:
10587 template <class T> void f() { extern T t; }
10589 where the entity referenced is not known until
10590 instantiation time. */
10594 {
10596 complain,
10598 /* If CTX is unchanged, then T is in fact the
10599 specialization we want. That situation occurs when
10600 referencing a static data member within in its own
10601 class. We can use pointer equality, rather than
10602 same_type_p, because DECL_CONTEXT is always
10603 canonical... */
10606 /* ... unless T is a member template; in which
10607 case our caller can be willing to create a
10608 specialization of that template represented
10609 by T. */
10613 }
10616 {
10624 }
10625 }
10626 else
10627 {
10628 /* A local variable. */
10630 /* Subsequent calls to pushdecl will fill this in. */
10633 }
10634 /* If we already have the specialization we need, there is
10635 nothing more to do. */
10637 {
10640 }
10643 {
10644 /* Just use name lookup to find a member alias for an anonymous
10645 union, but then add it to the hash table. */
10650 }
10652 /* Create a new node for the specialization we need. */
10655 {
10658 else
10665 }
10667 {
10668 /* Even if the original location is out of scope, the
10669 newly substituted one is not. */
10676 {
10677 /* It may seem that this case cannot occur, since:
10679 typedef void f();
10680 void g() { f x; }
10682 declares a function, not a variable. However:
10684 typedef void f();
10685 template <typename T> void g() { T t; }
10686 template void g<f>();
10688 is an attempt to declare a variable with function
10689 type. */
10691 /* R is not yet sufficiently initialized, so we
10692 just use its name. */
10695 }
10697 /* Wait until cp_finish_decl to set this again, to handle
10698 circular dependency (template/instantiate6.C). */
10703 {
10708 {
10711 }
10713 }
10714 }
10720 /* Clear out the mangled name and RTL for the instantiation. */
10724 /* The initializer must not be expanded until it is required;
10725 see [temp.inst]. */
10731 {
10732 /* Possibly limit visibility based on template args. */
10735 {
10739 }
10741 }
10744 {
10745 /* A static data member declaration is always marked
10746 external when it is declared in-class, even if an
10747 initializer is present. We mimic the non-template
10748 processing here. */
10754 }
10756 {
10757 /* We're substituting this var in a decltype outside of its
10758 scope, such as for a lambda return type. Don't add it to
10759 local_specializations, do perform auto deduction. */
10762 {
10763 tree init
10769 }
10770 }
10771 else
10780 /* Preserve a typedef that names a type. */
10782 {
10785 }
10788 }
10793 }
10794 #undef RETURN
10796 out:
10797 /* Restore the file and line information. */
10801 }
10803 /* Substitute into the ARG_TYPES of a function type.
10804 If END is a TREE_CHAIN, leave it and any following types
10805 un-substituted. */
10807 static tree
10809 tree args,
10810 tree end,
10811 tsubst_flags_t complain,
10812 tree in_decl)
10813 {
10814 tree remaining_arg_types;
10818 tree default_arg;
10829 {
10830 /* For a pack expansion, perform substitution on the
10831 entire expression. Later on, we'll handle the arguments
10832 one-by-one. */
10837 /* So that we'll spin through the parameters, one by one. */
10839 else
10840 {
10841 /* We only partially substituted into the parameter
10842 pack. Our type is TYPE_PACK_EXPANSION. */
10845 }
10846 }
10859 {
10861 {
10865 }
10867 }
10868 /* DR 657. */
10872 /* Do array-to-pointer, function-to-pointer conversion, and ignore
10873 top-level qualifiers as required. */
10876 /* We do not substitute into default arguments here. The standard
10877 mandates that they be instantiated only when needed, which is
10878 done in build_over_call. */
10882 {
10883 /* We've instantiated a template before its default arguments
10884 have been parsed. This can happen for a nested template
10885 class, and is not an error unless we require the default
10886 argument in a call of this function. */
10887 remaining_arg_types =
10890 }
10891 else
10892 remaining_arg_types =
10894 }
10897 }
10899 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
10900 *not* handle the exception-specification for FNTYPE, because the
10901 initial substitution of explicitly provided template parameters
10902 during argument deduction forbids substitution into the
10903 exception-specification:
10905 [temp.deduct]
10907 All references in the function type of the function template to the
10908 corresponding template parameters are replaced by the specified tem-
10909 plate argument values. If a substitution in a template parameter or
10910 in the function type of the function template results in an invalid
10911 type, type deduction fails. [Note: The equivalent substitution in
10912 exception specifications is done only when the function is instanti-
10913 ated, at which point a program is ill-formed if the substitution
10914 results in an invalid type.] */
10916 static tree
10918 tree args,
10919 tsubst_flags_t complain,
10920 tree in_decl)
10921 {
10922 tree return_type;
10923 tree arg_types;
10924 tree fntype;
10926 /* The TYPE_CONTEXT is not used for function/method types. */
10929 /* Substitute the return type. */
10933 /* DR 486 clarifies that creation of a function type with an
10934 invalid return type is a deduction failure. */
10937 {
10939 {
10942 else
10944 }
10946 }
10947 /* And DR 657. */
10951 /* Substitute the argument types. */
10957 /* Construct a new type node and return it. */
10959 {
10964 }
10965 else
10966 {
10969 {
10970 /* [temp.deduct]
10972 Type deduction may fail for any of the following
10973 reasons:
10975 -- Attempting to create "pointer to member of T" when T
10976 is not a class type. */
10979 r);
10981 }
10986 }
10990 }
10992 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
10993 ARGS into that specification, and return the substituted
10994 specification. If there is no specification, return NULL_TREE. */
10996 static tree
10998 tree args,
10999 tsubst_flags_t complain,
11000 tree in_decl,
11002 {
11003 tree specs;
11004 tree new_specs;
11009 {
11010 /* A noexcept-specifier. */
11015 {
11016 /* Defer instantiation of noexcept-specifiers to avoid
11017 excessive instantiations (c++/49107). */
11020 {
11021 /* We already partially instantiated this member template,
11022 so combine the new args with the old. */
11027 }
11028 else
11029 {
11032 }
11033 }
11034 else
11035 new_specs = tsubst_copy_and_build
11039 }
11041 {
11044 else
11046 {
11047 tree spec;
11052 {
11053 /* Expand the pack expansion type. */
11056 in_decl);
11062 else
11063 {
11064 /* We're substituting into a member template, so
11065 we got a TYPE_PACK_EXPANSION back. Add that
11066 expansion and move on. */
11070 expanded_specs,
11071 complain);
11074 }
11075 }
11078 {
11081 else
11086 complain);
11087 }
11090 }
11091 }
11093 }
11095 /* Take the tree structure T and replace template parameters used
11096 therein with the argument vector ARGS. IN_DECL is an associated
11097 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
11098 Issue error and warning messages under control of COMPLAIN. Note
11099 that we must be relatively non-tolerant of extensions here, in
11100 order to preserve conformance; if we allow substitutions that
11101 should not be allowed, we may allow argument deductions that should
11102 not succeed, and therefore report ambiguous overload situations
11103 where there are none. In theory, we could allow the substitution,
11104 but indicate that it should have failed, and allow our caller to
11105 make sure that the right thing happens, but we don't try to do this
11106 yet.
11108 This function is used for dealing with types, decls and the like;
11109 for expressions, use tsubst_expr or tsubst_copy. */
11111 tree
11113 {
11136 else
11141 /* Reuse typedefs. We need to do this to handle dependent attributes,
11142 such as attribute aligned. */
11145 {
11149 {
11150 /* DECL represents an alias template and we want to
11151 instantiate it. */
11155 }
11159 {
11163 }
11168 else
11169 /* The typedef is from a non-template context. */
11173 {
11175 r = cp_build_qualified_type_real
11179 }
11180 else
11181 {
11182 /* We don't have an instantiation yet, so drop the typedef. */
11187 }
11188 }
11201 {
11227 {
11233 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
11234 needed. */
11240 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
11241 with TREE_SIDE_EFFECTS that indicates this is not an integral
11242 constant expression. */
11245 {
11248 }
11251 }
11257 {
11270 {
11274 {
11275 /* See through ARGUMENT_PACK_SELECT arguments. */
11277 /* If the selected argument is an expansion E, that most
11278 likely means we were called from
11279 gen_elem_of_pack_expansion_instantiation during the
11280 substituting of pack an argument pack (which Ith
11281 element is a pack expansion, where I is
11282 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
11283 In this case, the Ith element resulting from this
11284 substituting is going to be a pack expansion, which
11285 pattern is the pattern of E. Let's return the
11286 pattern of E, and
11287 gen_elem_of_pack_expansion_instantiation will
11288 build the resulting pack expansion from it. */
11291 }
11292 }
11297 {
11299 /* If ARG is an argument pack, we don't actually want to
11300 perform a substitution here, because substitutions
11301 for argument packs are only done
11302 element-by-element. We can get to this point when
11303 substituting the type of a non-type template
11304 parameter pack, when that type actually contains
11305 template parameter packs from an outer template, e.g.,
11307 template<typename... Types> struct A {
11308 template<Types... Values> struct B { };
11309 }; */
11313 {
11319 return cp_build_qualified_type_real
11321 }
11323 {
11324 /* We are processing a type constructed from a
11325 template template parameter. */
11336 /* Consider this code:
11338 template <template <class> class Template>
11339 struct Internal {
11340 template <class Arg> using Bind = Template<Arg>;
11341 };
11343 template <template <class> class Template, class Arg>
11344 using Instantiate = Template<Arg>; //#0
11346 template <template <class> class Template,
11347 class Argument>
11348 using Bind =
11349 Instantiate<Internal<Template>::template Bind,
11350 Argument>; //#1
11352 When #1 is parsed, the
11353 BOUND_TEMPLATE_TEMPLATE_PARM representing the
11354 parameter `Template' in #0 matches the
11355 UNBOUND_CLASS_TEMPLATE representing the argument
11356 `Internal<Template>::template Bind'; We then want
11357 to assemble the type `Bind<Argument>' that can't
11358 be fully created right now, because
11359 `Internal<Template>' not being complete, the Bind
11360 template cannot be looked up in that context. So
11361 we need to "store" `Bind<Argument>' for later
11362 when the context of Bind becomes complete. Let's
11363 store that in a TYPENAME_TYPE. */
11367 argvec),
11368 typename_type,
11369 complain);
11371 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
11372 are resolving nested-types in the signature of a
11373 member function templates. Otherwise ARG is a
11374 TEMPLATE_DECL and is the real template to be
11375 instantiated. */
11383 complain);
11384 return cp_build_qualified_type_real
11386 }
11387 else
11388 /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */
11390 }
11393 /* This can happen during the attempted tsubst'ing in
11394 unify. This means that we don't yet have any information
11395 about the template parameter in question. */
11398 /* Early in template argument deduction substitution, we don't
11399 want to reduce the level of 'auto', or it will be confused
11400 with a normal template parm in subsequent deduction. */
11404 /* If we get here, we must have been looking at a parm for a
11405 more deeply nested template. Make a new version of this
11406 template parameter, but with a lower level. */
11408 {
11413 {
11415 r = cp_build_qualified_type_real
11419 }
11420 else
11421 {
11432 /* We have reduced the level of the template
11433 template parameter, but not the levels of its
11434 template parameters, so canonical_type_parameter
11435 will not be able to find the canonical template
11436 template parameter for this level. Thus, we
11437 require structural equality checking to compare
11438 TEMPLATE_TEMPLATE_PARMs. */
11442 else
11446 {
11454 }
11455 }
11464 }
11467 }
11470 {
11478 {
11482 }
11485 {
11489 }
11492 {
11496 }
11502 }
11505 /* We should never be tsubsting a binfo. */
11509 /* A vector of template arguments. */
11515 {
11519 /* [temp.deduct]
11521 Type deduction may fail for any of the following
11522 reasons:
11524 -- Attempting to create a pointer to reference type.
11525 -- Attempting to create a reference to a reference type or
11526 a reference to void.
11528 Core issue 106 says that creating a reference to a reference
11529 during instantiation is no longer a cause for failure. We
11530 only enforce this check in strict C++98 mode. */
11534 {
11537 /* We keep track of the last time we issued this error
11538 message to avoid spewing a ton of messages during a
11539 single bad template instantiation. */
11542 {
11547 else
11550 }
11553 }
11555 {
11559 }
11561 /* In C++0x, during template argument substitution, when there is an
11562 attempt to create a reference to a reference type, reference
11563 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
11565 "If a template-argument for a template-parameter T names a type
11566 that is a reference to a type A, an attempt to create the type
11567 'lvalue reference to cv T' creates the type 'lvalue reference to
11568 A,' while an attempt to create the type type rvalue reference to
11569 cv T' creates the type T"
11570 */
11571 r = cp_build_reference_type
11574 else
11579 /* Will this ever be needed for TYPE_..._TO values? */
11583 }
11585 {
11588 {
11589 /* [temp.deduct]
11591 Type deduction may fail for any of the following
11592 reasons:
11594 -- Attempting to create "pointer to member of T" when T
11595 is not a class type. */
11599 }
11601 {
11605 }
11607 {
11611 }
11614 {
11615 /* The type of the implicit object parameter gets its
11616 cv-qualifiers from the FUNCTION_TYPE. */
11617 tree memptr;
11618 tree method_type
11623 complain);
11624 }
11625 else
11628 complain);
11629 }
11632 {
11633 tree fntype;
11634 tree specs;
11639 /* Substitute the exception specification. */
11647 }
11649 {
11654 /* As an optimization, we avoid regenerating the array type if
11655 it will obviously be the same as T. */
11659 /* These checks should match the ones in grokdeclarator.
11661 [temp.deduct]
11663 The deduction may fail for any of the following reasons:
11665 -- Attempting to create an array with an element type that
11666 is void, a function type, or a reference type, or [DR337]
11667 an abstract class type. */
11671 {
11675 }
11677 {
11680 type);
11682 }
11687 {
11690 }
11693 }
11696 {
11706 {
11710 }
11712 {
11713 /* Normally, make_typename_type does not require that the CTX
11714 have complete type in order to allow things like:
11716 template <class T> struct S { typename S<T>::X Y; };
11718 But, such constructs have already been resolved by this
11719 point, so here CTX really should have complete type, unless
11720 it's a partial instantiation. */
11723 {
11727 }
11728 }
11735 {
11738 }
11741 {
11743 {
11747 else
11749 }
11751 {
11755 else
11757 }
11758 }
11760 return cp_build_qualified_type_real
11762 }
11765 {
11777 }
11780 {
11781 tree type;
11797 complain);
11798 }
11801 {
11802 tree type;
11818 else
11819 {
11823 /* In a template ~id could be either a complement expression
11824 or an unqualified-id naming a destructor; if instantiating
11825 it produces an expression, it's not an id-expression or
11826 member access. */
11829 }
11833 complain);
11834 }
11837 {
11841 }
11845 {
11847 tree packed_out =
11849 args,
11850 complain,
11851 in_decl);
11854 /* For template nontype argument packs, also substitute into
11855 the type. */
11860 }
11875 /* We should use one of the expression tsubsts for these codes. */
11881 }
11882 }
11884 /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the
11885 type of the expression on the left-hand side of the "." or "->"
11886 operator. */
11888 static tree
11891 {
11892 tree name;
11893 tree qualifying_scope;
11894 tree fns;
11895 tree optype;
11900 /* A baselink indicates a function from a base class. Both the
11901 BASELINK_ACCESS_BINFO and the base class referenced may
11902 indicate bases of the template class, rather than the
11903 instantiated class. In addition, lookups that were not
11904 ambiguous before may be ambiguous now. Therefore, we perform
11905 the lookup again. */
11912 {
11919 }
11927 /* If lookup found a single function, mark it as used at this
11928 point. (If it lookup found multiple functions the one selected
11929 later by overload resolution will be marked as used at that
11930 point.) */
11936 /* Add back the template arguments, if present. */
11941 template_args);
11942 /* Update the conversion operator type. */
11950 qualifying_scope,
11951 object_type);
11953 }
11955 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
11956 true if the qualified-id will be a postfix-expression in-and-of
11957 itself; false if more of the postfix-expression follows the
11958 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
11959 of "&". */
11961 static tree
11965 {
11966 tree expr;
11967 tree scope;
11968 tree name;
11970 tree template_args;
11975 /* Figure out what name to look up. */
11978 {
11986 }
11987 else
11988 {
11991 }
11993 /* Substitute into the qualifying scope. When there are no ARGS, we
11994 are just trying to simplify a non-dependent expression. In that
11995 case the qualifying scope may be dependent, and, in any case,
11996 substituting will not help. */
11999 {
12002 }
12003 else
12007 {
12012 }
12015 {
12017 {
12018 /* A BIT_NOT_EXPR is used to represent a destructor. */
12020 {
12024 }
12025 else
12028 }
12029 else
12033 {
12035 {
12039 }
12041 }
12042 }
12045 {
12047 scope);
12048 /* Remember that there was a reference to this entity. */
12050 }
12053 {
12059 }
12068 {
12069 expr = (adjust_result_of_qualified_name_lookup
12071 expr = (finish_qualified_id_expr
12075 }
12077 /* Expressions do not generally have reference type. */
12079 /* However, if we're about to form a pointer-to-member, we just
12080 want the referenced member referenced. */
12085 }
12087 /* Like tsubst, but deals with expressions. This function just replaces
12088 template parms; to finish processing the resultant expression, use
12089 tsubst_copy_and_build or tsubst_expr. */
12091 static tree
12093 {
12095 tree r;
12103 {
12108 {
12109 /* We get here for a use of 'this' in an NSDMI. */
12115 /* This can happen for a parameter name used later in a function
12116 declaration (such as in a late-specified return type). Just
12117 make a dummy decl, since it's only used for its type. */
12120 /* Give it the template pattern as its context; its true context
12121 hasn't been instantiated yet and this is good enough for
12122 mangling. */
12124 }
12132 {
12133 tree enum_type;
12134 tree v;
12138 /* There is no need to substitute into namespace-scope
12139 enumerators. */
12142 /* If ARGS is NULL, then T is known to be non-dependent. */
12146 /* Unfortunately, we cannot just call lookup_name here.
12147 Consider:
12149 template <int I> int f() {
12150 enum E { a = I };
12151 struct S { void g() { E e = a; } };
12152 };
12154 When we instantiate f<7>::S::g(), say, lookup_name is not
12155 clever enough to find f<7>::a. */
12156 enum_type
12166 /* We didn't find the name. That should never happen; if
12167 name-lookup found it during preliminary parsing, we
12168 should find it again here during instantiation. */
12170 }
12175 {
12176 tree ctx;
12181 {
12184 {
12188 }
12190 }
12191 }
12207 /* An OVERLOAD will always be a non-dependent overload set; an
12208 overload set from function scope will just be represented with an
12209 IDENTIFIER_NODE, and from class scope with a BASELINK. */
12224 {
12225 /* Template template argument like the following example need
12226 special treatment:
12228 template <template <class> class TT> struct C {};
12229 template <class T> struct D {
12230 template <class U> struct E {};
12231 C<E> c; // #1
12232 };
12233 D<int> d; // #2
12235 We are processing the template argument `E' in #1 for
12236 the template instantiation #2. Originally, `E' is a
12237 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
12238 have to substitute this with one having context `D<int>'. */
12242 }
12243 else
12244 /* Ordinary template template argument. */
12255 return build1
12261 {
12271 /* We only want to compute the number of arguments. */
12285 {
12292 else
12295 }
12296 else
12298 }
12300 {
12308 }
12309 /* Fall through */
12324 return build1
12329 {
12330 tree object;
12331 tree name;
12336 {
12340 }
12343 {
12353 }
12358 in_decl);
12359 else
12362 }
12400 return build_nt
12413 return build_nt
12420 {
12428 }
12433 {
12434 r = build_nt
12440 }
12443 {
12444 r = build_nt
12450 }
12453 {
12454 r = build_nt
12460 }
12463 {
12464 /* Substituted template arguments */
12473 }
12476 {
12496 }
12521 /* Fall through. */
12524 {
12527 }
12528 else
12532 /* This is handled by tsubst_copy_and_build. */
12538 in_decl),
12542 /* We shouldn't have built any of these during initial template
12543 generation. Instead, they should be built during instantiation
12544 in response to the saved STMT_IS_FULL_EXPR_P setting. */
12548 r = build2
12568 {
12569 /* Instantiate any typedefs in the type. */
12574 }
12577 /* These can sometimes show up in a partial instantiation, but never
12578 involve template parms. */
12583 /* We shouldn't get here, but keep going if !ENABLE_CHECKING. */
12586 }
12587 }
12589 /* Like tsubst_copy, but specifically for OpenMP clauses. */
12591 static tree
12593 tree in_decl)
12594 {
12598 {
12604 {
12607 {
12613 }
12614 /* FALLTHRU */
12638 }
12639 }
12642 }
12644 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
12646 static tree
12648 tree in_decl)
12649 {
12650 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
12670 {
12673 else
12674 {
12678 }
12679 }
12684 #undef RECUR
12685 }
12687 /* Substitute one OMP_FOR iterator. */
12689 static void
12694 {
12695 #define RECUR(NODE) \
12696 tsubst_expr ((NODE), args, complain, in_decl, \
12697 integral_constant_expression_p)
12705 /* Do this before substituting into decl to handle 'auto'. */
12710 {
12714 }
12719 {
12726 complain);
12727 else
12734 }
12737 {
12738 tree c;
12740 {
12751 }
12753 {
12758 {
12761 }
12762 }
12763 }
12769 else
12773 {
12784 {
12791 }
12792 else
12798 {
12804 }
12808 {
12815 }
12816 else
12822 }
12828 #undef RECUR
12829 }
12831 /* Like tsubst_copy for expressions, etc. but also does semantic
12832 processing. */
12834 static tree
12837 {
12838 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12839 #define RECUR(NODE) \
12840 tsubst_expr ((NODE), args, complain, in_decl, \
12841 integral_constant_expression_p)
12844 tree r;
12845 location_t loc;
12857 {
12859 {
12860 tree_stmt_iterator i;
12864 }
12879 else
12888 {
12890 tree init;
12896 {
12899 tree decl;
12907 else
12909 }
12910 else
12911 {
12915 {
12916 /* By marking the declaration as instantiated, we avoid
12917 trying to instantiate it. Since instantiate_decl can't
12918 handle local variables, and since we've already done
12919 all that needs to be done, that's the right thing to
12920 do. */
12925 /* Anonymous aggregates are a special case. */
12928 {
12931 {
12935 }
12937 }
12940 else
12941 {
12946 {
12947 /* For __PRETTY_FUNCTION__ we have to adjust the
12948 initializer. */
12952 }
12953 else
12954 {
12958 {
12959 /* If we had an initializer but it
12960 instantiated to nothing,
12961 value-initialize the object. This will
12962 only occur when the initializer was a
12963 pack expansion where the parameter packs
12964 used in that expansion were of length
12965 zero. */
12967 complain);
12970 }
12971 else
12973 }
12976 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
12979 }
12980 }
12981 }
12984 }
12999 {
13009 }
13036 {
13040 }
13048 else
13056 else
13083 {
13085 tree label;
13090 }
13096 /* Computed goto's must be tsubst'd into. On the other hand,
13097 non-computed gotos must not be; the identifier in question
13098 will have no binding. */
13100 else
13106 tmp = finish_asm_stmt
13113 {
13118 }
13123 {
13128 }
13129 else
13130 {
13135 else
13142 else
13148 else
13150 }
13154 {
13158 {
13160 /* Prevent instantiate_decl from trying to instantiate
13161 this variable. We've already done all that needs to be
13162 done. */
13165 }
13170 }
13176 {
13177 /* Local classes are not independent templates; they are
13178 instantiated along with their containing function. And this
13179 way we don't have to deal with pushing out of one local class
13180 to instantiate a member of another local class. */
13181 tree fn;
13182 /* Closures are handled by the LAMBDA_EXPR. */
13188 }
13192 {
13193 tree condition;
13196 condition =
13198 args,
13207 }
13228 {
13245 integral_constant_expression_p);
13259 }
13291 {
13296 {
13299 }
13304 }
13305 else
13306 {
13313 {
13316 }
13319 {
13324 {
13327 }
13331 }
13332 else
13333 {
13337 }
13339 }
13343 {
13349 {
13353 {
13358 }
13362 }
13363 else
13364 {
13369 }
13370 }
13388 /* If the first operand was a statement, we're done with it. */
13392 complain));
13399 integral_constant_expression_p));
13400 }
13403 out:
13406 #undef RECUR
13407 #undef RETURN
13408 }
13410 /* T is a postfix-expression that is not being used in a function
13411 call. Return the substituted version of T. */
13413 static tree
13415 tsubst_flags_t complain,
13416 tree in_decl)
13417 {
13421 else
13427 }
13429 /* Like tsubst but deals with expressions and performs semantic
13430 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
13432 tree
13434 tree args,
13435 tsubst_flags_t complain,
13436 tree in_decl,
13439 {
13440 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
13441 #define RECUR(NODE) \
13442 tsubst_copy_and_build (NODE, args, complain, in_decl, \
13444 integral_constant_expression_p)
13447 location_t loc;
13456 /* N3276 decltype magic only applies to calls at the top level or on the
13457 right side of a comma. */
13462 {
13465 /* Fall through. */
13467 {
13468 tree decl;
13469 cp_id_kind idk;
13474 {
13477 }
13479 /* Look up the name. */
13482 /* By convention, expressions use ERROR_MARK_NODE to indicate
13483 failure, not NULL_TREE. */
13489 integral_constant_expression_p,
13497 input_location);
13501 {
13505 }
13507 }
13510 {
13511 tree object;
13519 {
13522 }
13523 else
13530 else
13532 }
13535 {
13539 {
13540 /* A type conversion to reference type will be enclosed in
13541 such an indirect ref, but the substitution of the cast
13542 will have also added such an indirect ref. */
13545 }
13546 else
13550 }
13558 {
13565 flags));
13566 }
13579 {
13580 tree type;
13586 {
13591 }
13597 {
13615 }
13619 }
13653 else
13655 in_decl);
13690 {
13691 tree r;
13695 r = build_x_binary_op
13699 ? ERROR_MARK
13703 ? ERROR_MARK
13713 }
13732 /* Fall through */
13735 {
13736 tree r;
13742 {
13743 /* When there are no ARGS, we are trying to evaluate a
13744 non-dependent expression from the parser. Trying to do
13745 the substitutions may not work. */
13748 }
13749 else
13750 {
13755 else
13758 /*integral_constant_expression_p=*/
13762 }
13766 else
13770 {
13772 {
13774 {
13778 }
13779 else
13783 }
13785 }
13787 }
13790 {
13800 }
13814 {
13815 tree r = build_x_modify_expr
13821 /* TREE_NO_WARNING must be set if either the expression was
13822 parenthesized or it uses an operator such as >>= rather
13823 than plain assignment. In the former case, it was already
13824 set and must be copied. In the latter case,
13825 build_x_modify_expr sets it and it must not be reset
13826 here. */
13830 }
13835 /* Remember that there was a reference to this entity. */
13841 {
13846 tree ret;
13850 else
13851 {
13855 }
13857 /* If there was an initializer in the original tree, but it
13858 instantiated to an empty list, then we should pass a
13859 non-NULL empty vector to tell build_new that it was an
13860 empty initializer() rather than no initializer. This can
13861 only happen when the initializer is a pack expansion whose
13862 parameter packs are of length zero. */
13865 else
13866 {
13870 else
13871 {
13874 }
13875 }
13882 complain);
13890 }
13898 complain));
13901 {
13905 integral_constant_expression_p);
13907 op0,
13910 }
13913 {
13914 tree function;
13919 tree ret;
13922 /* When we parsed the expression, we determined whether or
13923 not Koenig lookup should be performed. */
13926 {
13931 }
13933 {
13934 /* Do nothing; calling tsubst_copy_and_build on an identifier
13935 would incorrectly perform unqualified lookup again.
13937 Note that we can also have an IDENTIFIER_NODE if the earlier
13938 unqualified lookup found a member function; in that case
13939 koenig_p will be false and we do want to do the lookup
13940 again to find the instantiated member function.
13942 FIXME but doing that causes c++/15272, so we need to stop
13943 using IDENTIFIER_NODE in that situation. */
13945 }
13946 else
13947 {
13949 {
13955 }
13956 else
13961 /* Avoid error about taking the address of a constructor. */
13965 in_decl,
13967 integral_constant_expression_p);
13971 }
13976 {
13981 else
13982 {
13983 /* Expand the pack expansion and push each entry onto
13984 CALL_ARGS. */
13987 {
13992 {
13997 }
13998 }
13999 else
14000 {
14001 /* A partial substitution. Add one entry. */
14003 }
14004 }
14005 }
14007 /* We do not perform argument-dependent lookup if normal
14008 lookup finds a non-function, in accordance with the
14009 expected resolution of DR 218. */
14012 /* If lookup found a member function, the Koenig lookup is
14013 not appropriate, even if an unqualified-name was used
14014 to denote the function. */
14017 /* Only do this when substitution turns a dependent call
14018 into a non-dependent call. */
14022 tf_none);
14026 {
14028 {
14029 /* For backwards compatibility and good diagnostics, try
14030 the unqualified lookup again if we aren't in SFINAE
14031 context. */
14032 tree unq = (tsubst_copy_and_build
14034 integral_constant_expression_p));
14039 {
14048 "%qD was not declared in this scope, "
14049 "and no declarations were found by "
14050 "argument-dependent lookup at the point "
14055 {
14057 "declarations in dependent base %qT are "
14063 else
14067 }
14068 else
14072 }
14073 }
14075 {
14080 }
14081 }
14083 /* Remember that there was a reference to this entity. */
14087 /* Put back tf_decltype for the actual call. */
14092 complain);
14094 {
14109 complain);
14110 else
14111 ret = (build_new_method_call
14116 complain));
14117 }
14118 else
14121 koenig_p,
14122 complain);
14127 }
14130 {
14135 {
14137 {
14142 }
14143 else
14144 {
14149 }
14150 }
14151 else
14152 {
14155 }
14159 }
14168 {
14176 {
14177 /* We have pack expansions, so expand those and
14178 create a new list out of it. */
14181 tree chain;
14184 /* Expand the argument expressions. */
14192 /* Build the rest of the list. */
14197 /* Determine the number of arguments. */
14199 {
14202 }
14205 else
14206 {
14207 /* Since we only performed a partial substitution into
14208 the argument pack, we only RETURN (a single list
14209 node. */
14216 }
14218 /* Convert the argument vectors into a TREE_LIST */
14221 {
14222 /* Grab the Ith values. */
14223 i--;
14226 value
14230 /* Build the list (backwards). */
14232 }
14235 }
14251 }
14254 {
14255 tree object;
14256 tree object_type;
14257 tree member;
14261 /* Remember that there was a reference to this entity. */
14271 else
14279 {
14281 {
14286 {
14289 }
14291 {
14295 }
14296 }
14297 }
14300 {
14301 /* Lookup the template functions now that we know what the
14302 scope is. */
14310 {
14313 args);
14314 member = (adjust_result_of_qualified_name_lookup
14316 object_type));
14317 }
14318 else
14319 {
14321 input_location);
14323 }
14324 }
14328 {
14330 {
14334 else
14337 }
14339 }
14345 complain));
14346 }
14353 {
14361 tree r;
14366 /* digest_init will do the wrong thing if we let it. */
14370 /* We do not want to process the index of aggregate
14371 initializers as they are identifier nodes which will be
14372 looked up by digest_init. */
14378 {
14380 /* An identifier index is looked up in the type
14381 being initialized, not the current scope. */
14386 {
14387 /* Substitute into the pack expansion. */
14389 in_decl);
14393 ;
14395 /* Just move the argument into place. */
14397 else
14398 {
14399 /* Update the length of the final CONSTRUCTOR
14400 arguments vector, and note that we will need to
14401 copy.*/
14404 }
14405 }
14406 else
14408 }
14411 {
14416 {
14418 {
14423 }
14424 else
14426 }
14427 }
14437 }
14440 {
14443 {
14446 }
14447 else
14448 {
14451 }
14452 }
14457 /* Fall through */
14460 {
14464 /* If the original type was a reference, we'll be wrapped in
14465 the appropriate INDIRECT_REF. */
14468 }
14479 {
14488 }
14491 {
14497 integral_constant_expression_p);
14501 /* If the resulting list of expression statement is empty,
14502 fold it further into void_zero_node. */
14507 }
14510 {
14524 /* For a function scope, we want to use tsubst so that we don't
14525 complain about referring to an auto function before its return
14526 type has been deduced. Otherwise, we want to use tsubst_copy so
14527 that we look up the existing field/parameter/variable rather
14528 than build a new one. */
14533 {
14534 /* Look up the parameter we want directly, as tsubst_copy
14535 doesn't do what we need. */
14541 /* FIXME Work around the parm not having DECL_CONTEXT set. */
14544 }
14545 else
14554 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
14556 /* Now that we know visibility, instantiate the type so we have a
14557 declaration of the op() for later calls to lambda_function. */
14563 }
14566 /* We can get here for a constant initializer of non-dependent type.
14567 FIXME stop folding in cp_parser_initializer_clause. */
14568 {
14570 complain);
14572 }
14576 integral_constant_expression_p));
14579 /* Handle Objective-C++ constructs, if appropriate. */
14580 {
14581 tree subst
14586 }
14588 }
14590 #undef RECUR
14591 #undef RETURN
14592 out:
14595 }
14597 /* Verify that the instantiated ARGS are valid. For type arguments,
14598 make sure that the type's linkage is ok. For non-type arguments,
14599 make sure they are constants if they are integral or enumerations.
14600 Emit an error under control of COMPLAIN, and return TRUE on error. */
14602 static bool
14604 {
14608 {
14618 }
14620 {
14621 /* [basic.link]: A name with no linkage (notably, the name
14622 of a class or enumeration declared in a local scope)
14623 shall not be used to declare an entity with linkage.
14624 This implies that names with no linkage cannot be used as
14625 template arguments
14627 DR 757 relaxes this restriction for C++0x. */
14632 {
14633 /* DR 488 makes use of a type with no linkage cause
14634 type deduction to fail. */
14636 {
14639 else
14642 }
14644 }
14645 /* In order to avoid all sorts of complications, we do not
14646 allow variably-modified types as template arguments. */
14648 {
14652 }
14653 }
14654 /* Class template and alias template arguments should be OK. */
14656 ;
14657 /* A non-type argument of integral or enumerated type must be a
14658 constant. */
14662 {
14666 }
14668 }
14670 static bool
14672 {
14677 {
14680 }
14684 }
14686 /* We're out of SFINAE context now, so generate diagnostics for the access
14687 errors we saw earlier when instantiating D from TMPL and ARGS. */
14689 static void
14691 {
14703 }
14705 /* Instantiate the indicated variable, function, or alias template TMPL with
14706 the template arguments in TARG_PTR. */
14708 static tree
14710 {
14712 tree fndecl;
14713 tree gen_tmpl;
14714 tree spec;
14722 /* If this function is a clone, handle it specially. */
14724 {
14725 tree spec;
14726 tree clone;
14728 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
14729 DECL_CLONED_FUNCTION. */
14735 /* Look for the clone. */
14739 /* We should always have found the clone by now. */
14742 }
14744 /* Check to see if we already have this specialization. */
14747 /* The TMPL is a partial instantiation. To get a full set of
14748 arguments we must add the arguments used to perform the
14749 partial instantiation. */
14751 targ_ptr);
14753 /* It would be nice to avoid hashing here and then again in tsubst_decl,
14754 but it doesn't seem to be on the hot path. */
14763 {
14765 {
14769 }
14771 }
14774 complain))
14777 /* We are building a FUNCTION_DECL, during which the access of its
14778 parameters and return types have to be checked. However this
14779 FUNCTION_DECL which is the desired context for access checking
14780 is not built yet. We solve this chicken-and-egg problem by
14781 deferring all checks until we have the FUNCTION_DECL. */
14784 /* Instantiation of the function happens in the context of the function
14785 template, not the context of the overload resolution we're doing. */
14789 /* If there are dependent arguments, e.g. because we're doing partial
14790 ordering, make sure processing_template_decl stays set. */
14794 {
14798 }
14799 /* Substitute template parameters to obtain the specialization. */
14808 {
14811 }
14813 /* The DECL_TI_TEMPLATE should always be the immediate parent
14814 template, not the most general template. */
14817 /* Now we know the specialization, compute access previously
14818 deferred. */
14825 /* If we've just instantiated the main entry point for a function,
14826 instantiate all the alternate entry points as well. We do this
14827 by cloning the instantiation of the main entry point, not by
14828 instantiating the template clones. */
14833 {
14835 {
14836 /* Remember to reinstantiate when we're out of SFINAE so the user
14837 can see the errors. */
14839 }
14841 }
14843 }
14845 /* Wrapper for instantiate_template_1. */
14847 tree
14849 {
14850 tree ret;
14855 }
14857 /* Instantiate the alias template TMPL with ARGS. Also push a template
14858 instantiation level, which instantiate_template doesn't do because
14859 functions and variables have sufficient context established by the
14860 callers. */
14862 static tree
14864 {
14871 {
14874 }
14876 args =
14884 /* We can't free this if a pending_template entry or last_error_tinst_level
14885 is pointing at it. */
14891 }
14893 /* PARM is a template parameter pack for FN. Returns true iff
14894 PARM is used in a deducible way in the argument list of FN. */
14896 static bool
14898 {
14901 {
14903 tree packs;
14909 {
14910 /* The template parameter pack is used in a function parameter
14911 pack. If this is the end of the parameter list, the
14912 template parameter pack is deducible. */
14915 else
14916 /* Otherwise, not. Well, it could be deduced from
14917 a non-pack parameter, but doing so would end up with
14918 a deduction mismatch, so don't bother. */
14920 }
14921 }
14922 /* The template parameter pack isn't used in any function parameter
14923 packs, but it might be used deeper, e.g. tuple<Args...>. */
14925 }
14927 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
14928 NARGS elements of the arguments that are being used when calling
14929 it. TARGS is a vector into which the deduced template arguments
14930 are placed.
14932 Return zero for success, 2 for an incomplete match that doesn't resolve
14933 all the types, and 1 for complete failure. An error message will be
14934 printed only for an incomplete match.
14936 If FN is a conversion operator, or we are trying to produce a specific
14937 specialization, RETURN_TYPE is the return type desired.
14939 The EXPLICIT_TARGS are explicit template arguments provided via a
14940 template-id.
14942 The parameter STRICT is one of:
14944 DEDUCE_CALL:
14945 We are deducing arguments for a function call, as in
14946 [temp.deduct.call].
14948 DEDUCE_CONV:
14949 We are deducing arguments for a conversion function, as in
14950 [temp.deduct.conv].
14952 DEDUCE_EXACT:
14953 We are deducing arguments when doing an explicit instantiation
14954 as in [temp.explicit], when determining an explicit specialization
14955 as in [temp.expl.spec], or when taking the address of a function
14956 template, as in [temp.deduct.funcaddr]. */
14958 tree
14960 tree explicit_targs,
14961 tree targs,
14964 tree return_type,
14965 unification_kind_t strict,
14968 {
14969 tree parms;
14970 tree fntype;
14978 tree tinst;
14981 /* In C++0x, it's possible to have a function template whose type depends
14982 on itself recursively. This is most obvious with decltype, but can also
14983 occur with enumeration scope (c++/48969). So we need to catch infinite
14984 recursion and reject the substitution at deduction time; this function
14985 will return error_mark_node for any repeated substitution.
14987 This also catches excessive recursion such as when f<N> depends on
14988 f<N-1> across all integers, and returns error_mark_node for all the
14989 substitutions back up to the initial one.
14991 This is, of course, not reentrant. */
15001 {
15002 /* [temp.deduct]
15004 The specified template arguments must match the template
15005 parameters in kind (i.e., type, nontype, template), and there
15006 must not be more arguments than there are parameters;
15007 otherwise type deduction fails.
15009 Nontype arguments must match the types of the corresponding
15010 nontype template parameters, or must be convertible to the
15011 types of the corresponding nontype parameters as specified in
15012 _temp.arg.nontype_, otherwise type deduction fails.
15014 All references in the function type of the function template
15015 to the corresponding template parameters are replaced by the
15016 specified template argument values. If a substitution in a
15017 template parameter or in the function type of the function
15018 template results in an invalid type, type deduction fails. */
15023 /* Adjust any explicit template arguments before entering the
15024 substitution context. */
15025 explicit_targs
15027 complain,
15033 /* Substitute the explicit args into the function type. This is
15034 necessary so that, for instance, explicitly declared function
15035 arguments can match null pointed constants. If we were given
15036 an incomplete set of explicit args, we must not do semantic
15037 processing during substitution as we could create partial
15038 instantiations. */
15040 {
15045 /* Dig out the actual parm. */
15048 {
15051 }
15053 {
15056 }
15059 /* No explicit argument for this template parameter. */
15063 {
15064 /* Mark the argument pack as "incomplete". We could
15065 still deduce more arguments during unification.
15066 We remove this mark in type_unification_real. */
15068 {
15072 }
15074 /* We have some incomplete argument packs. */
15076 }
15077 }
15081 {
15084 }
15087 /* Ignore any access checks; we'll see them again in
15088 instantiate_template and they might have the wrong
15089 access path at this point. */
15101 /* Place the explicitly specified arguments in TARGS. */
15104 }
15106 /* Never do unification on the 'this' parameter. */
15110 {
15119 }
15121 /* We allow incomplete unification without an error message here
15122 because the standard doesn't seem to explicitly prohibit it. Our
15123 callers must be ready to deal with unification failures in any
15124 event. */
15126 /* type_unification_real will pass back any access checks from default
15127 template argument substitution. */
15138 /* Now that we have bindings for all of the template arguments,
15139 ensure that the arguments deduced for the template template
15140 parameters have compatible template parameter lists. We cannot
15141 check this property before we have deduced all template
15142 arguments, because the template parameter types of a template
15143 template parameter might depend on prior template parameters
15144 deduced after the template template parameter. The following
15145 ill-formed example illustrates this issue:
15147 template<typename T, template<T> class C> void f(C<5>, T);
15149 template<int N> struct X {};
15151 void g() {
15152 f(X<5>(), 5l); // error: template argument deduction fails
15153 }
15155 The template parameter list of 'C' depends on the template type
15156 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
15157 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
15158 time that we deduce 'C'. */
15161 {
15164 }
15166 /* All is well so far. Now, check:
15168 [temp.deduct]
15170 When all template arguments have been deduced, all uses of
15171 template parameters in nondeduced contexts are replaced with
15172 the corresponding deduced argument values. If the
15173 substitution results in an invalid type, as described above,
15174 type deduction fails. */
15177 {
15180 }
15182 /* Also collect access checks from the instantiation. */
15195 /* Now perform any access checks encountered during substitution. */
15202 /* If we're looking for an exact match, check that what we got
15203 is indeed an exact match. It might not be if some template
15204 parameters are used in non-deduced contexts. But don't check
15205 for an exact match if we have dependent template arguments;
15206 in that case we're doing partial ordering, and we already know
15207 that we have two candidates that will provide the actual type. */
15209 {
15213 tree sarg
15219 {
15223 }
15224 }
15228 fail:
15231 {
15233 /* Reset once we're all the way out. */
15235 }
15237 /* We can't free this if a pending_template entry or last_error_tinst_level
15238 is pointing at it. */
15244 }
15246 /* Adjust types before performing type deduction, as described in
15247 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
15248 sections are symmetric. PARM is the type of a function parameter
15249 or the return type of the conversion function. ARG is the type of
15250 the argument passed to the call, or the type of the value
15251 initialized with the result of the conversion function.
15252 ARG_EXPR is the original argument expression, which may be null. */
15254 static int
15258 tree arg_expr)
15259 {
15263 {
15268 {
15269 /* Swap PARM and ARG throughout the remainder of this
15270 function; the handling is precisely symmetric since PARM
15271 will initialize ARG rather than vice versa. */
15276 }
15279 /* Core issue #873: Do the DR606 thing (see below) for these cases,
15280 too, but here handle it by stripping the reference from PARM
15281 rather than by adding it to ARG. */
15289 /* Nothing else to do in this case. */
15294 }
15297 {
15298 /* [temp.deduct.call]
15300 If P is not a reference type:
15302 --If A is an array type, the pointer type produced by the
15303 array-to-pointer standard conversion (_conv.array_) is
15304 used in place of A for type deduction; otherwise,
15306 --If A is a function type, the pointer type produced by
15307 the function-to-pointer standard conversion
15308 (_conv.func_) is used in place of A for type deduction;
15309 otherwise,
15311 --If A is a cv-qualified type, the top level
15312 cv-qualifiers of A's type are ignored for type
15313 deduction. */
15318 else
15320 }
15322 /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is
15323 of the form T&&, where T is a template parameter, and the argument
15324 is an lvalue, T is deduced as A& */
15330 /* try_one_overload doesn't provide an arg_expr, but
15331 functions are always lvalues. */
15335 /* [temp.deduct.call]
15337 If P is a cv-qualified type, the top level cv-qualifiers
15338 of P's type are ignored for type deduction. If P is a
15339 reference type, the type referred to by P is used for
15340 type deduction. */
15343 {
15346 }
15348 /* DR 322. For conversion deduction, remove a reference type on parm
15349 too (which has been swapped into ARG). */
15354 }
15356 /* Subroutine of unify_one_argument. PARM is a function parameter of a
15357 template which does contain any deducible template parameters; check if
15358 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
15359 unify_one_argument. */
15361 static int
15364 {
15365 tree type;
15369 else
15376 {
15380 }
15382 {
15387 }
15391 else
15393 }
15395 /* Subroutine of type_unification_real and unify_pack_expansion to
15396 handle unification of a single P/A pair. Parameters are as
15397 for those functions. */
15399 static int
15403 {
15410 /* We can't deduce anything from this, but we might get all the
15411 template args from other function args. */
15414 /* FIXME uses_deducible_template_parms */
15417 explain_p);
15420 {
15422 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
15423 | UNIFY_ALLOW_MORE_CV_QUAL
15437 }
15439 /* We only do these transformations if this is the top-level
15440 parameter_type_list in a call or declaration matching; in other
15441 situations (nested function declarators, template argument lists) we
15442 won't be comparing a type to an expression, and we don't do any type
15443 adjustments. */
15445 {
15447 {
15450 {
15451 /* [temp.deduct.type] A template-argument can be
15452 deduced from a pointer to function or pointer
15453 to member function argument if the set of
15454 overloaded functions does not contain function
15455 templates and at most one of a set of
15456 overloaded functions provides a unique
15457 match. */
15464 }
15470 }
15472 arg_strict |=
15474 }
15475 else
15479 /* For deduction from an init-list we need the actual list. */
15483 }
15485 /* Most parms like fn_type_unification.
15487 If SUBR is 1, we're being called recursively (to unify the
15488 arguments of a function or method parameter of a function
15489 template).
15491 CHECKS is a pointer to a vector of access checks encountered while
15492 substituting default template arguments. */
15494 static int
15496 tree targs,
15497 tree xparms,
15501 unification_kind_t strict,
15505 {
15510 tree parms;
15519 /* Reset the number of non-defaulted template arguments contained
15520 in TARGS. */
15523 again:
15531 {
15536 /* For a function parameter pack that occurs at the end of the
15537 parameter-declaration-list, the type A of each remaining
15538 argument of the call is compared with the type P of the
15539 declarator-id of the function parameter pack. */
15545 /* For a function parameter pack that does not occur at the
15546 end of the parameter-declaration-list, the type of the
15547 parameter pack is a non-deduced context. */
15556 }
15561 {
15562 /* Unify the remaining arguments with the pack expansion type. */
15563 tree argvec;
15566 /* Allocate a TREE_VEC and copy in all of the arguments */
15571 /* Copy the parameter into parmvec. */
15577 /* Advance to the end of the list of parameters. */
15579 }
15581 /* Fail if we've reached the end of the parm list, and more args
15582 are present, and the parm list isn't variadic. */
15585 /* Fail if parms are left and they don't have default values. */
15588 {
15592 {
15593 count++;
15595 }
15597 }
15600 {
15601 tsubst_flags_t complain = (explain_p
15602 ? tf_warning_or_error
15606 {
15610 /* Clear the "incomplete" flags on all argument packs now so that
15611 substituting them into later default arguments works. */
15613 {
15616 }
15622 /* If this is an undeduced nontype parameter that depends on
15623 a type parameter, try another pass; its type may have been
15624 deduced from a later argument than the one from which
15625 this parameter can be deduced. */
15631 /* Core issue #226 (C++0x) [temp.deduct]:
15633 If a template argument has not been deduced, its
15634 default template argument, if any, is used.
15636 When we are in C++98 mode, TREE_PURPOSE will either
15637 be NULL_TREE or ERROR_MARK_NODE, so we do not need
15638 to explicitly check cxx_dialect here. */
15640 {
15655 else
15656 {
15658 /* The position of the first default template argument,
15659 is also the number of non-defaulted arguments in TARGS.
15660 Record that. */
15664 }
15665 }
15667 /* If the type parameter is a parameter pack, then it will
15668 be deduced to an empty parameter pack. */
15670 {
15671 tree arg;
15674 {
15678 }
15679 else
15686 }
15689 }
15690 }
15691 #ifdef ENABLE_CHECKING
15694 #endif
15697 }
15699 /* Subroutine of type_unification_real. Args are like the variables
15700 at the call site. ARG is an overloaded function (or template-id);
15701 we try deducing template args from each of the overloads, and if
15702 only one succeeds, we go with that. Modifies TARGS and returns
15703 true on success. */
15705 static bool
15707 tree targs,
15708 tree parm,
15709 tree arg,
15710 unification_kind_t strict,
15713 {
15720 {
15723 }
15724 else
15728 /* Handle `&x' where `x' is some static or non-static member
15729 function name. */
15735 /* Strip baselink information. */
15740 {
15741 /* If we got some explicit template args, we need to plug them into
15742 the affected templates before we try to unify, in case the
15743 explicit args will completely resolve the templates in question. */
15750 {
15763 {
15768 {
15771 }
15772 }
15775 }
15776 /* If no templates (or more than one) are fully resolved by the
15777 explicit arguments, this template-id is a non-deduced context; it
15778 could still be OK if we deduce all template arguments for the
15779 enclosing call through other arguments. */
15782 }
15785 /* If ARG is, for example, "(0, &f)" then its type will be unknown
15786 -- but the deduction does not succeed because the expression is
15787 not just the function on its own. */
15789 else
15795 {
15798 }
15800 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15801 to function or pointer to member function argument if the set of
15802 overloaded functions does not contain function templates and at most
15803 one of a set of overloaded functions provides a unique match.
15805 So if we found multiple possibilities, we return success but don't
15806 deduce anything. */
15809 {
15814 }
15819 }
15821 /* Core DR 115: In contexts where deduction is done and fails, or in
15822 contexts where deduction is not done, if a template argument list is
15823 specified and it, along with any default template arguments, identifies
15824 a single function template specialization, then the template-id is an
15825 lvalue for the function template specialization. */
15827 tree
15829 {
15842 {
15845 }
15847 {
15850 }
15852 {
15855 }
15858 {
15862 /* If we got some explicit template args, we need to plug them into
15863 the affected templates before we try to unify, in case the
15864 explicit args will completely resolve the templates in question. */
15872 {
15885 {
15888 {
15891 }
15893 {
15896 }
15897 }
15898 }
15900 {
15908 {
15909 tree base
15912 }
15916 }
15918 /* There were no good options and at least one bad one, so let the
15919 user know what the problem is. */
15921 }
15923 }
15925 /* Subroutine of resolve_overloaded_unification; does deduction for a single
15926 overload. Fills TARGS with any deduced arguments, or error_mark_node if
15927 different overloads deduce different arguments for a given parm.
15928 ADDR_P is true if the expression for which deduction is being
15929 performed was of the form "& fn" rather than simply "fn".
15931 Returns 1 on success. */
15933 static int
15935 tree orig_targs,
15936 tree targs,
15937 tree parm,
15938 tree arg,
15939 unification_kind_t strict,
15943 {
15945 tree tempargs;
15951 /* [temp.deduct.type] A template-argument can be deduced from a pointer
15952 to function or pointer to member function argument if the set of
15953 overloaded functions does not contain function templates and at most
15954 one of a set of overloaded functions provides a unique match.
15956 So if this is a template, just return success. */
15968 /* We don't copy orig_targs for this because if we have already deduced
15969 some template args from previous args, unify would complain when we
15970 try to deduce a template parameter for the same argument, even though
15971 there isn't really a conflict. */
15978 /* First make sure we didn't deduce anything that conflicts with
15979 explicitly specified args. */
15981 {
15988 /* Since we're unifying against ourselves, we will fill in
15989 template args used in the function parm list with our own
15990 template parms. Discard them. */
15994 }
15997 {
16002 }
16005 }
16007 /* PARM is a template class (perhaps with unbound template
16008 parameters). ARG is a fully instantiated type. If ARG can be
16009 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
16010 TARGS are as for unify. */
16012 static tree
16015 {
16016 tree copy_of_targs;
16023 /* We need to make a new template argument vector for the call to
16024 unify. If we used TARGS, we'd clutter it up with the result of
16025 the attempted unification, even if this class didn't work out.
16026 We also don't want to commit ourselves to all the unifications
16027 we've already done, since unification is supposed to be done on
16028 an argument-by-argument basis. In other words, consider the
16029 following pathological case:
16031 template <int I, int J, int K>
16032 struct S {};
16034 template <int I, int J>
16035 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
16037 template <int I, int J, int K>
16038 void f(S<I, J, K>, S<I, I, I>);
16040 void g() {
16041 S<0, 0, 0> s0;
16042 S<0, 1, 2> s2;
16044 f(s0, s2);
16045 }
16047 Now, by the time we consider the unification involving `s2', we
16048 already know that we must have `f<0, 0, 0>'. But, even though
16049 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
16050 because there are two ways to unify base classes of S<0, 1, 2>
16051 with S<I, I, I>. If we kept the already deduced knowledge, we
16052 would reject the possibility I=1. */
16055 /* If unification failed, we're done. */
16061 }
16063 /* Given a template type PARM and a class type ARG, find the unique
16064 base type in ARG that is an instance of PARM. We do not examine
16065 ARG itself; only its base-classes. If there is not exactly one
16066 appropriate base class, return NULL_TREE. PARM may be the type of
16067 a partial specialization, as well as a plain template type. Used
16068 by unify. */
16070 static enum template_base_result
16073 {
16075 tree binfo;
16081 {
16082 /* The type could not be completed. */
16085 }
16087 /* Walk in inheritance graph order. The search order is not
16088 important, and this avoids multiple walks of virtual bases. */
16090 {
16095 {
16096 /* If there is more than one satisfactory baseclass, then:
16098 [temp.deduct.call]
16100 If they yield more than one possible deduced A, the type
16101 deduction fails.
16103 applies. */
16105 {
16108 }
16111 }
16112 }
16116 }
16118 /* Returns the level of DECL, which declares a template parameter. */
16120 static int
16122 {
16124 {
16134 }
16136 }
16138 /* Decide whether ARG can be unified with PARM, considering only the
16139 cv-qualifiers of each type, given STRICT as documented for unify.
16140 Returns nonzero iff the unification is OK on that basis. */
16142 static int
16144 {
16150 {
16151 /* Although a CVR qualifier is ignored when being applied to a
16152 substituted template parameter ([8.3.2]/1 for example), that
16153 does not allow us to unify "const T" with "int&" because both
16154 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
16155 It is ok when we're allowing additional CV qualifiers
16156 at the outer level [14.8.2.1]/3,1st bullet. */
16166 }
16177 }
16179 /* Determines the LEVEL and INDEX for the template parameter PARM. */
16180 void
16182 {
16186 {
16189 }
16190 else
16191 {
16194 }
16195 }
16197 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
16198 do { \
16199 if (unify (TP, TA, P, A, S, EP)) \
16200 return 1; \
16201 } while (0);
16203 /* Unifies the remaining arguments in PACKED_ARGS with the pack
16204 expansion at the end of PACKED_PARMS. Returns 0 if the type
16205 deduction succeeds, 1 otherwise. STRICT is the same as in
16206 unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function
16207 call argument list. We'll need to adjust the arguments to make them
16208 types. SUBR tells us if this is from a recursive call to
16209 type_unification_real, or for comparing two template argument
16210 lists. */
16212 static int
16216 {
16217 tree parm
16227 /* Determine the parameter packs we will be deducing from the
16228 pattern, and record their current deductions. */
16231 {
16235 /* Determine the index and level of this parameter pack. */
16238 /* Keep track of the parameter packs and their corresponding
16239 argument packs. */
16242 }
16244 /* Loop through all of the arguments that have not yet been
16245 unified and unify each with the pattern. */
16247 {
16248 tree parm;
16252 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
16253 or the element of its argument pack at the current index if
16254 this argument was explicitly specified. */
16256 {
16265 {
16268 }
16270 }
16272 /* If we had explicit template arguments, substitute them into the
16273 pattern before deduction. */
16275 {
16276 /* Some arguments might still be unspecified or dependent. */
16284 NULL_TREE);
16289 }
16290 else
16293 /* Unify the pattern with the current argument. */
16298 /* For each parameter pack, collect the deduced value. */
16300 {
16306 }
16307 }
16309 /* Verify that the results of unification with the parameter packs
16310 produce results consistent with what we've seen before, and make
16311 the deduced argument packs available. */
16313 {
16320 /* By default keep the original deduced argument pack.
16321 If necessary, more specific code is going to update the
16322 resulting deduced argument later down in this function. */
16326 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
16327 actually deduce anything. */
16335 {
16336 /* If we had fewer function args than explicit template args,
16337 just use the explicits. */
16342 }
16345 {
16346 tree result;
16347 /* Build the deduced *_ARGUMENT_PACK. */
16349 {
16354 }
16355 else
16360 /* Note the deduced argument packs for this parameter
16361 pack. */
16363 }
16367 {
16368 /* We only had the explicitly-provided arguments before, but
16369 now we have a complete set of arguments. */
16375 }
16376 else
16377 {
16383 /* Inconsistent unification of this parameter pack. */
16385 bad_old_arg,
16386 bad_new_arg);
16387 }
16388 }
16391 }
16393 /* Deduce the value of template parameters. TPARMS is the (innermost)
16394 set of template parameters to a template. TARGS is the bindings
16395 for those template parameters, as determined thus far; TARGS may
16396 include template arguments for outer levels of template parameters
16397 as well. PARM is a parameter to a template function, or a
16398 subcomponent of that parameter; ARG is the corresponding argument.
16399 This function attempts to match PARM with ARG in a manner
16400 consistent with the existing assignments in TARGS. If more values
16401 are deduced, then TARGS is updated.
16403 Returns 0 if the type deduction succeeds, 1 otherwise. The
16404 parameter STRICT is a bitwise or of the following flags:
16406 UNIFY_ALLOW_NONE:
16407 Require an exact match between PARM and ARG.
16408 UNIFY_ALLOW_MORE_CV_QUAL:
16409 Allow the deduced ARG to be more cv-qualified (by qualification
16410 conversion) than ARG.
16411 UNIFY_ALLOW_LESS_CV_QUAL:
16412 Allow the deduced ARG to be less cv-qualified than ARG.
16413 UNIFY_ALLOW_DERIVED:
16414 Allow the deduced ARG to be a template base class of ARG,
16415 or a pointer to a template base class of the type pointed to by
16416 ARG.
16417 UNIFY_ALLOW_INTEGER:
16418 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
16419 case for more information.
16420 UNIFY_ALLOW_OUTER_LEVEL:
16421 This is the outermost level of a deduction. Used to determine validity
16422 of qualification conversions. A valid qualification conversion must
16423 have const qualified pointers leading up to the inner type which
16424 requires additional CV quals, except at the outer level, where const
16425 is not required [conv.qual]. It would be normal to set this flag in
16426 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
16427 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
16428 This is the outermost level of a deduction, and PARM can be more CV
16429 qualified at this point.
16430 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
16431 This is the outermost level of a deduction, and PARM can be less CV
16432 qualified at this point. */
16434 static int
16437 {
16439 tree targ;
16440 tree tparm;
16443 /* I don't think this will do the right thing with respect to types.
16444 But the only case I've seen it in so far has been array bounds, where
16445 signedness is the only information lost, and I think that will be
16446 okay. */
16454 /* We can't deduce anything from this, but we might get all the
16455 template args from other function args. */
16458 /* If PARM uses template parameters, then we can't bail out here,
16459 even if ARG == PARM, since we won't record unifications for the
16460 template parameters. We might need them if we're trying to
16461 figure out which of two things is more specialized. */
16465 /* Handle init lists early, so the rest of the function can assume
16466 we're dealing with a type. */
16468 {
16473 /* Replace T with std::initializer_list<T> for deduction. */
16479 /* We can only deduce from an initializer list argument if the
16480 parameter is std::initializer_list; otherwise this is a
16481 non-deduced context. */
16487 {
16494 {
16496 /* It should only be possible to get here for a call. */
16498 elt_strict |= maybe_adjust_types_for_deduction
16501 }
16504 explain_p);
16505 }
16507 /* If the std::initializer_list<T> deduction worked, replace the
16508 deduced A with std::initializer_list<A>. */
16510 {
16515 }
16517 }
16519 /* Immediately reject some pairs that won't unify because of
16520 cv-qualification mismatches. */
16523 /* It is the elements of the array which hold the cv quals of an array
16524 type, and the elements might be template type parms. We'll check
16525 when we recurse. */
16527 /* We check the cv-qualifiers when unifying with template type
16528 parameters below. We want to allow ARG `const T' to unify with
16529 PARM `T' for example, when computing which of two templates
16530 is more specialized, for example. */
16544 {
16548 /* In a type which contains a nested-name-specifier, template
16549 argument values cannot be deduced for template parameters used
16550 within the nested-name-specifier. */
16562 /* The PARM is not one we're trying to unify. Just check
16563 to see if it matches ARG. */
16564 {
16569 else
16571 }
16578 /* Check for mixed types and values. */
16586 {
16587 /* ARG must be constructed from a template class or a template
16588 template parameter. */
16593 {
16597 tree parm_parms
16598 = DECL_INNERMOST_TEMPLATE_PARMS
16603 /* The resolution to DR150 makes clear that default
16604 arguments for an N-argument may not be used to bind T
16605 to a template template parameter with fewer than N
16606 parameters. It is not safe to permit the binding of
16607 default arguments as an extension, as that may change
16608 the meaning of a conforming program. Consider:
16610 struct Dense { static const unsigned int dim = 1; };
16612 template <template <typename> class View,
16613 typename Block>
16614 void operator+(float, View<Block> const&);
16616 template <typename Block,
16617 unsigned int Dim = Block::dim>
16618 struct Lvalue_proxy { operator float() const; };
16620 void
16621 test_1d (void) {
16622 Lvalue_proxy<Dense> p;
16623 float b;
16624 b + p;
16625 }
16627 Here, if Lvalue_proxy is permitted to bind to View, then
16628 the global operator+ will be used; if they are not, the
16629 Lvalue_proxy will be converted to float. */
16631 full_argvec,
16633 (explain_p
16634 ? tf_warning_or_error
16641 /* Deduce arguments T, i from TT<T> or TT<i>.
16642 We check each element of PARMVEC and ARGVEC individually
16643 rather than the whole TREE_VEC since they can have
16644 different number of elements. */
16651 /* Check if the parameters end in a pack, making them
16652 variadic. */
16658 /* If the template argument list of P contains a pack
16659 expansion that is not the last template argument, the
16660 entire template argument list is a non-deduced
16661 context. */
16670 {
16675 }
16680 DEDUCE_EXACT,
16683 }
16686 /* Fall through to deduce template name. */
16687 }
16691 {
16692 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
16694 /* Simple cases: Value already set, does match or doesn't. */
16699 }
16700 else
16701 {
16702 /* If PARM is `const T' and ARG is only `int', we don't have
16703 a match unless we are allowing additional qualification.
16704 If ARG is `const int' and PARM is just `T' that's OK;
16705 that binds `const int' to `T'. */
16710 /* Consider the case where ARG is `const volatile int' and
16711 PARM is `const T'. Then, T should be `volatile int'. */
16712 arg = cp_build_qualified_type_real
16717 /* Simple cases: Value already set, does match or doesn't. */
16723 /* Make sure that ARG is not a variable-sized array. (Note
16724 that were talking about variable-sized arrays (like
16725 `int[n]'), rather than arrays of unknown size (like
16726 `int[]').) We'll get very confused by such a type since
16727 the bound of the array is not constant, and therefore
16728 not mangleable. Besides, such types are not allowed in
16729 ISO C++, so we can do as we please here. We do allow
16730 them for 'auto' deduction, since that isn't ABI-exposed. */
16734 /* Strip typedefs as in convert_template_argument. */
16736 }
16738 /* If ARG is a parameter pack or an expansion, we cannot unify
16739 against it unless PARM is also a parameter pack. */
16744 /* If the argument deduction results is a METHOD_TYPE,
16745 then there is a problem.
16746 METHOD_TYPE doesn't map to any real C++ type the result of
16747 the deduction can not be of that type. */
16761 {
16762 /* The PARM is not one we're trying to unify. Just check
16763 to see if it matches ARG. */
16769 }
16775 {
16780 }
16782 /* [temp.deduct.type] If, in the declaration of a function template
16783 with a non-type template-parameter, the non-type
16784 template-parameter is used in an expression in the function
16785 parameter-list and, if the corresponding template-argument is
16786 deduced, the template-argument type shall match the type of the
16787 template-parameter exactly, except that a template-argument
16788 deduced from an array bound may be of any integral type.
16789 The non-type parameter might use already deduced type parameters. */
16792 /* Template-parameter dependent expression. Just accept it for now.
16793 It will later be processed in convert_template_argument. */
16794 ;
16800 /* Convert the ARG to the type of PARM; the deduced non-type
16801 template argument must exactly match the types of the
16802 corresponding parameter. */
16805 /* We haven't deduced the type of this parameter yet. Try again
16806 later. */
16808 else
16811 /* If ARG is a parameter pack or an expansion, we cannot unify
16812 against it unless PARM is also a parameter pack. */
16822 {
16823 /* A pointer-to-member constant can be unified only with
16824 another constant. */
16828 /* Just unify the class member. It would be useless (and possibly
16829 wrong, depending on the strict flags) to unify also
16830 PTRMEM_CST_CLASS, because we want to be sure that both parm and
16831 arg refer to the same variable, even if through different
16832 classes. For instance:
16834 struct A { int x; };
16835 struct B : A { };
16837 Unification of &A::x and &B::x must succeed. */
16840 }
16843 {
16847 /* [temp.deduct.call]
16849 A can be another pointer or pointer to member type that can
16850 be converted to the deduced A via a qualification
16851 conversion (_conv.qual_).
16853 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
16854 This will allow for additional cv-qualification of the
16855 pointed-to types if appropriate. */
16858 /* The derived-to-base conversion only persists through one
16859 level of pointers. */
16864 }
16881 {
16882 tree parm_max;
16883 tree arg_max;
16887 /* Our representation of array types uses "N - 1" as the
16888 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
16889 not an integer constant. We cannot unify arbitrarily
16890 complex expressions, so we eliminate the MINUS_EXPRs
16891 here. */
16895 {
16898 }
16902 {
16903 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
16904 trying to unify the type of a variable with the type
16905 of a template parameter. For example:
16907 template <unsigned int N>
16908 void f (char (&) [N]);
16909 int g();
16910 void h(int i) {
16911 char a[g(i)];
16912 f(a);
16913 }
16915 Here, the type of the ARG will be "int [g(i)]", and
16916 may be a SAVE_EXPR, etc. */
16920 }
16922 /* If only one of the bounds used a MINUS_EXPR, compensate
16923 by adding one to the other bound. */
16926 integer_type_node,
16927 parm_max,
16928 integer_one_node);
16931 integer_type_node,
16932 arg_max,
16933 integer_one_node);
16937 }
16951 /* We have already checked cv-qualification at the top of the
16952 function. */
16956 /* As far as unification is concerned, this wins. Later checks
16957 will invalidate it if necessary. */
16960 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
16961 /* Type INTEGER_CST can come from ordinary constant template args. */
16973 {
16983 /* Check for pack expansions in the parameters. */
16985 {
16987 {
16989 /* We can unify against something with a trailing
16990 parameter pack. */
16992 else
16993 /* [temp.deduct.type]/9: If the template argument list of
16994 P contains a pack expansion that is not the last
16995 template argument, the entire template argument list
16996 is a non-deduced context. */
16998 }
16999 }
17001 /* If we don't have enough arguments to satisfy the parameters
17002 (not counting the pack expression at the end), or we have
17003 too many arguments for a parameter list that doesn't end in
17004 a pack expression, we can't unify. */
17010 /* Unify all of the parameters that precede the (optional)
17011 pack expression. */
17013 {
17018 }
17021 DEDUCE_EXACT,
17024 }
17032 {
17040 }
17043 {
17047 {
17048 /* First, we try to unify the PARM and ARG directly. */
17053 {
17054 /* Fallback to the special case allowed in
17055 [temp.deduct.call]:
17057 If P is a class, and P has the form
17058 template-id, then A can be a derived class of
17059 the deduced A. Likewise, if P is a pointer to
17060 a class of the form template-id, A can be a
17061 pointer to a derived class pointed to by the
17062 deduced A. */
17069 }
17070 }
17074 /* Perhaps PARM is something like S<U> and ARG is S<int>.
17075 Then, we should unify `int' and `U'. */
17077 else
17078 /* There's no chance of unification succeeding. */
17083 }
17090 {
17093 tree a;
17099 /* CV qualifications for methods can never be deduced, they must
17100 match exactly. We need to check them explicitly here,
17101 because type_unification_real treats them as any other
17102 cv-qualified parameter. */
17104 && (!check_cv_quals_for_unify
17124 }
17127 /* Unify a pointer to member with a pointer to member function, which
17128 deduces the type of the member as a function type. */
17130 {
17131 tree method_type;
17132 tree fntype;
17134 /* Check top-level cv qualifiers */
17142 /* Determine the type of the function we are unifying against. */
17144 fntype =
17148 /* Extract the cv-qualifiers and ref-qualifier of the member
17149 function from the implicit object parameter and place them
17150 on the function type to be restored later. */
17155 }
17174 /* Matched cases are handled by the ARG == PARM test above. */
17178 /* A non-type template parameter that is a variable should be a
17179 an integral constant, in which case, it whould have been
17180 folded into its (constant) value. So we should not be getting
17181 a variable here. */
17192 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
17193 or UNDERLYING_TYPE nodes. */
17197 /* Unification fails if we hit an error node. */
17201 /* An unresolved overload is a nondeduced context. */
17206 /* We must be looking at an expression. This can happen with
17207 something like:
17209 template <int I>
17210 void foo(S<I>, S<I + 2>);
17212 This is a "nondeduced context":
17214 [deduct.type]
17216 The nondeduced contexts are:
17218 --A type that is a template-id in which one or more of
17219 the template-arguments is an expression that references
17220 a template-parameter.
17222 In these cases, we assume deduction succeeded, but don't
17223 actually infer any unifications. */
17228 else
17230 }
17231 }
17232 #undef RECUR_AND_CHECK_FAILURE
17233 \f
17234 /* Note that DECL can be defined in this translation unit, if
17235 required. */
17237 static void
17239 {
17240 tree clone;
17244 }
17246 /* Called if RESULT is explicitly instantiated, or is a member of an
17247 explicitly instantiated class. */
17249 void
17251 {
17254 /* If this entity has already been written out, it's too late to
17255 make any modifications. */
17260 /* The TREE_PUBLIC flag for function declarations will have been
17261 set correctly by tsubst. */
17264 /* This might have been set by an earlier implicit instantiation. */
17269 else
17270 {
17272 /* Always make artificials weak. */
17275 /* For WIN32 we also want to put explicit instantiations in
17276 linkonce sections. */
17279 }
17281 /* If EXTERN_P, then this function will not be emitted -- unless
17282 followed by an explicit instantiation, at which point its linkage
17283 will be adjusted. If !EXTERN_P, then this function will be
17284 emitted here. In neither circumstance do we want
17285 import_export_decl to adjust the linkage. */
17287 }
17289 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
17290 important template arguments. If any are missing, we check whether
17291 they're important by using error_mark_node for substituting into any
17292 args that were used for partial ordering (the ones between ARGS and END)
17293 and seeing if it bubbles up. */
17295 static bool
17297 {
17302 {
17305 }
17307 {
17311 }
17313 }
17315 /* Given two function templates PAT1 and PAT2, return:
17317 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
17318 -1 if PAT2 is more specialized than PAT1.
17319 0 if neither is more specialized.
17321 LEN indicates the number of parameters we should consider
17322 (defaulted parameters should not be considered).
17324 The 1998 std underspecified function template partial ordering, and
17325 DR214 addresses the issue. We take pairs of arguments, one from
17326 each of the templates, and deduce them against each other. One of
17327 the templates will be more specialized if all the *other*
17328 template's arguments deduce against its arguments and at least one
17329 of its arguments *does* *not* deduce against the other template's
17330 corresponding argument. Deduction is done as for class templates.
17331 The arguments used in deduction have reference and top level cv
17332 qualifiers removed. Iff both arguments were originally reference
17333 types *and* deduction succeeds in both directions, the template
17334 with the more cv-qualified argument wins for that pairing (if
17335 neither is more cv-qualified, they both are equal). Unlike regular
17336 deduction, after all the arguments have been deduced in this way,
17337 we do *not* verify the deduced template argument values can be
17338 substituted into non-deduced contexts.
17340 The logic can be a bit confusing here, because we look at deduce1 and
17341 targs1 to see if pat2 is at least as specialized, and vice versa; if we
17342 can find template arguments for pat1 to make arg1 look like arg2, that
17343 means that arg2 is at least as specialized as arg1. */
17345 int
17347 {
17360 /* Remove the this parameter from non-static member functions. If
17361 one is a non-static member function and the other is not a static
17362 member function, remove the first parameter from that function
17363 also. This situation occurs for operator functions where we
17364 locate both a member function (with this pointer) and non-member
17365 operator (with explicit first operand). */
17367 {
17372 }
17374 {
17377 {
17378 len--;
17380 }
17381 }
17383 /* If only one is a conversion operator, they are unordered. */
17387 /* Consider the return type for a conversion function */
17389 {
17392 len++;
17393 }
17395 processing_template_decl++;
17401 /* Stop when an ellipsis is seen. */
17403 {
17412 {
17413 /* When both arguments are pack expansions, we need only
17414 unify the patterns themselves. */
17418 /* This is the last comparison we need to do. */
17420 }
17423 {
17426 }
17429 {
17432 }
17438 {
17444 /* Setup the parameter vector, which contains only ARG1. */
17447 /* Setup the argument vector, which contains the remaining
17448 arguments. */
17457 /* We cannot deduce in the other direction, because ARG1 is
17458 a pack expansion but ARG2 is not. */
17460 }
17462 {
17468 /* Setup the parameter vector, which contains only ARG1. */
17471 /* Setup the argument vector, which contains the remaining
17472 arguments. */
17481 /* We cannot deduce in the other direction, because ARG2 is
17482 a pack expansion but ARG1 is not.*/
17484 }
17486 else
17487 {
17488 /* The normal case, where neither argument is a pack
17489 expansion. */
17496 }
17498 /* If we couldn't deduce arguments for tparms1 to make arg1 match
17499 arg2, then arg2 is not as specialized as arg1. */
17505 /* "If, for a given type, deduction succeeds in both directions
17506 (i.e., the types are identical after the transformations above)
17507 and if the type from the argument template is more cv-qualified
17508 than the type from the parameter template (as described above)
17509 that type is considered to be more specialized than the other. If
17510 neither type is more cv-qualified than the other then neither type
17511 is more specialized than the other." */
17515 {
17520 }
17523 /* We've failed to deduce something in either direction.
17524 These must be unordered. */
17529 /* We have already processed all of the arguments in our
17530 handing of the pack expansion type. */
17535 }
17537 /* "In most cases, all template parameters must have values in order for
17538 deduction to succeed, but for partial ordering purposes a template
17539 parameter may remain without a value provided it is not used in the
17540 types being used for partial ordering."
17542 Thus, if we are missing any of the targs1 we need to substitute into
17543 origs1, then pat2 is not as specialized as pat1. This can happen when
17544 there is a nondeduced context. */
17550 processing_template_decl--;
17552 /* All things being equal, if the next argument is a pack expansion
17553 for one function but not for the other, prefer the
17554 non-variadic function. FIXME this is bogus; see c++/41958. */
17558 {
17561 }
17567 else
17569 }
17571 /* Determine which of two partial specializations of TMPL is more
17572 specialized.
17574 PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding
17575 to the first partial specialization. The TREE_VALUE is the
17576 innermost set of template parameters for the partial
17577 specialization. PAT2 is similar, but for the second template.
17579 Return 1 if the first partial specialization is more specialized;
17580 -1 if the second is more specialized; 0 if neither is more
17581 specialized.
17583 See [temp.class.order] for information about determining which of
17584 two templates is more specialized. */
17586 static int
17588 {
17589 tree targs;
17597 /* Just like what happens for functions, if we are ordering between
17598 different class template specializations, we may encounter dependent
17599 types in the arguments, and we need our dependency check functions
17600 to behave correctly. */
17606 {
17609 }
17615 {
17618 }
17621 /* In the case of a tie where at least one of the class templates
17622 has a parameter pack at the end, the template with the most
17623 non-packed parameters wins. */
17625 && any_deductions
17628 {
17634 /* We don't count the pack expansion at the end. */
17644 }
17647 }
17649 /* Return the template arguments that will produce the function signature
17650 DECL from the function template FN, with the explicit template
17651 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
17652 also match. Return NULL_TREE if no satisfactory arguments could be
17653 found. */
17655 static tree
17657 {
17661 tree decl_arg_types;
17664 tree arg;
17668 /* Never do unification on the 'this' parameter. */
17688 }
17690 /* Return the innermost template arguments that, when applied to a partial
17691 specialization of TMPL whose innermost template parameters are
17692 TPARMS, and whose specialization arguments are SPEC_ARGS, yield the
17693 ARGS.
17695 For example, suppose we have:
17697 template <class T, class U> struct S {};
17698 template <class T> struct S<T*, int> {};
17700 Then, suppose we want to get `S<double*, int>'. The TPARMS will be
17701 {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*,
17702 int}. The resulting vector will be {double}, indicating that `T'
17703 is bound to `double'. */
17705 static tree
17707 {
17709 tree deduced_args;
17710 tree innermost_deduced_args;
17714 {
17718 innermost_deduced_args);
17719 }
17720 else
17733 /* Verify that nondeduced template arguments agree with the type
17734 obtained from argument deduction.
17736 For example:
17738 struct A { typedef int X; };
17739 template <class T, class U> struct C {};
17740 template <class T> struct C<T, typename T::X> {};
17742 Then with the instantiation `C<A, int>', we can deduce that
17743 `T' is `A' but unify () does not check whether `typename T::X'
17744 is `int'. */
17750 /* We only need to check the innermost arguments; the other
17751 arguments will always agree. */
17756 /* Now that we have bindings for all of the template arguments,
17757 ensure that the arguments deduced for the template template
17758 parameters have compatible template parameter lists. See the use
17759 of template_template_parm_bindings_ok_p in fn_type_unification
17760 for more information. */
17765 }
17767 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
17768 Return the TREE_LIST node with the most specialized template, if
17769 any. If there is no most specialized template, the error_mark_node
17770 is returned.
17772 Note that this function does not look at, or modify, the
17773 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
17774 returned is one of the elements of INSTANTIATIONS, callers may
17775 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
17776 and retrieve it from the value returned. */
17778 tree
17780 {
17787 {
17793 fate--;
17798 fate++;
17803 {
17804 /* Equally specialized, move to next function. If there
17805 is no next function, nothing's most specialized. */
17810 }
17811 }
17814 /* Now verify that champ is better than everything earlier in the
17815 instantiation list. */
17823 {
17826 }
17828 processing_template_decl--;
17834 }
17836 /* If DECL is a specialization of some template, return the most
17837 general such template. Otherwise, returns NULL_TREE.
17839 For example, given:
17841 template <class T> struct S { template <class U> void f(U); };
17843 if TMPL is `template <class U> void S<int>::f(U)' this will return
17844 the full template. This function will not trace past partial
17845 specializations, however. For example, given in addition:
17847 template <class T> struct S<T*> { template <class U> void f(U); };
17849 if TMPL is `template <class U> void S<int*>::f(U)' this will return
17850 `template <class T> template <class U> S<T*>::f(U)'. */
17852 tree
17854 {
17855 /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is
17856 an immediate specialization. */
17858 {
17862 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a
17863 template friend. */
17868 }
17870 /* Look for more and more general templates. */
17872 {
17873 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
17874 (See cp-tree.h for details.) */
17882 /* Stop if we run into an explicitly specialized class template. */
17889 }
17892 }
17894 /* Return the most specialized of the class template partial
17895 specializations which can produce TYPE, a specialization of some class
17896 template. The value returned is actually a TREE_LIST; the TREE_TYPE is
17897 a _TYPE node corresponding to the partial specialization, while the
17898 TREE_PURPOSE is the set of template arguments that must be
17899 substituted into the TREE_TYPE in order to generate TYPE.
17901 If the choice of partial specialization is ambiguous, a diagnostic
17902 is issued, and the error_mark_node is returned. If there are no
17903 partial specializations matching TYPE, then NULL_TREE is
17904 returned, indicating that the primary template should be used. */
17906 static tree
17908 {
17910 tree t;
17911 tree champ;
17920 /* For determining which partial specialization to use, only the
17921 innermost args are interesting. */
17923 {
17926 }
17929 {
17930 tree partial_spec_args;
17931 tree spec_args;
17939 {
17942 /* Discard the outer levels of args, and then substitute in the
17943 template args from the enclosing class. */
17945 partial_spec_args = tsubst_template_args
17948 /* PARMS already refers to just the innermost parms, but the
17949 template parms in partial_spec_args had their levels lowered
17950 by tsubst, so we need to do the same for the parm list. We
17951 can't just tsubst the TREE_VEC itself, as tsubst wants to
17952 treat a TREE_VEC as an argument vector. */
17958 }
17960 partial_spec_args =
17962 partial_spec_args,
17973 partial_spec_args,
17974 args);
17976 {
17981 }
17982 }
17992 {
17995 ;
17996 else
17997 {
17999 {
18002 {
18005 }
18006 }
18008 }
18009 }
18013 {
18016 {
18019 }
18020 }
18023 {
18031 {
18034 }
18037 }
18040 }
18042 /* Explicitly instantiate DECL. */
18044 void
18046 {
18051 /* An error occurred, for which grokdeclarator has already issued
18052 an appropriate message. */
18055 {
18058 }
18060 {
18061 /* There is an asymmetry here in the way VAR_DECLs and
18062 FUNCTION_DECLs are handled by grokdeclarator. In the case of
18063 the latter, the DECL we get back will be marked as a
18064 template instantiation, and the appropriate
18065 DECL_TEMPLATE_INFO will be set up. This does not happen for
18066 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
18067 should handle VAR_DECLs as it currently handles
18068 FUNCTION_DECLs. */
18070 {
18073 }
18076 {
18079 }
18081 {
18086 }
18087 }
18089 {
18092 }
18093 else
18096 /* Check for various error cases. Note that if the explicit
18097 instantiation is valid the RESULT will currently be marked as an
18098 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
18099 until we get here. */
18102 {
18103 /* DR 259 [temp.spec].
18105 Both an explicit instantiation and a declaration of an explicit
18106 specialization shall not appear in a program unless the explicit
18107 instantiation follows a declaration of the explicit specialization.
18109 For a given set of template parameters, if an explicit
18110 instantiation of a template appears after a declaration of an
18111 explicit specialization for that template, the explicit
18112 instantiation has no effect. */
18114 }
18116 {
18117 /* [temp.spec]
18119 No program shall explicitly instantiate any template more
18120 than once.
18122 We check DECL_NOT_REALLY_EXTERN so as not to complain when
18123 the first instantiation was `extern' and the second is not,
18124 and EXTERN_P for the opposite case. */
18127 /* If an "extern" explicit instantiation follows an ordinary
18128 explicit instantiation, the template is instantiated. */
18131 }
18133 {
18136 }
18138 {
18141 }
18144 ;
18146 {
18149 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
18152 }
18153 else
18161 }
18163 static void
18165 {
18171 {
18174 }
18175 }
18177 /* Called from do_type_instantiation through binding_table_foreach to
18178 do recursive instantiation for the type bound in ENTRY. */
18179 static void
18181 {
18187 }
18189 /* Called from do_type_instantiation to instantiate a member
18190 (a member function or a static member variable) of an
18191 explicitly instantiated class template. */
18192 static void
18194 {
18199 }
18201 /* Perform an explicit instantiation of template class T. STORAGE, if
18202 non-null, is the RID for extern, inline or static. COMPLAIN is
18203 nonzero if this is called from the parser, zero if called recursively,
18204 since the standard is unclear (as detailed below). */
18206 void
18208 {
18218 {
18219 tree tmpl =
18223 else
18226 }
18231 {
18234 t);
18236 }
18239 {
18241 {
18243 {
18246 "ISO C++ 1998 forbids the use of %<extern%> on "
18248 }
18249 else
18251 "ISO C++ forbids the use of %qE"
18253 }
18261 else
18262 {
18264 storage);
18266 }
18267 }
18270 {
18271 /* DR 259 [temp.spec].
18273 Both an explicit instantiation and a declaration of an explicit
18274 specialization shall not appear in a program unless the explicit
18275 instantiation follows a declaration of the explicit specialization.
18277 For a given set of template parameters, if an explicit
18278 instantiation of a template appears after a declaration of an
18279 explicit specialization for that template, the explicit
18280 instantiation has no effect. */
18282 }
18284 {
18285 /* [temp.spec]
18287 No program shall explicitly instantiate any template more
18288 than once.
18290 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
18291 instantiation was `extern'. If EXTERN_P then the second is.
18292 These cases are OK. */
18299 /* If we've already instantiated the template, just return now. */
18302 }
18310 {
18311 tree tmp;
18313 /* In contrast to implicit instantiation, where only the
18314 declarations, and not the definitions, of members are
18315 instantiated, we have here:
18317 [temp.explicit]
18319 The explicit instantiation of a class template specialization
18320 implies the instantiation of all of its members not
18321 previously explicitly specialized in the translation unit
18322 containing the explicit instantiation.
18324 Of course, we can't instantiate member template classes, since
18325 we don't have any arguments for them. Note that the standard
18326 is unclear on whether the instantiation of the members are
18327 *explicit* instantiations or not. However, the most natural
18328 interpretation is that it should be an explicit instantiation. */
18343 }
18344 }
18346 /* Given a function DECL, which is a specialization of TMPL, modify
18347 DECL to be a re-instantiation of TMPL with the same template
18348 arguments. TMPL should be the template into which tsubst'ing
18349 should occur for DECL, not the most general template.
18351 One reason for doing this is a scenario like this:
18353 template <class T>
18354 void f(const T&, int i);
18356 void g() { f(3, 7); }
18358 template <class T>
18359 void f(const T& t, const int i) { }
18361 Note that when the template is first instantiated, with
18362 instantiate_template, the resulting DECL will have no name for the
18363 first parameter, and the wrong type for the second. So, when we go
18364 to instantiate the DECL, we regenerate it. */
18366 static void
18368 {
18369 /* The arguments used to instantiate DECL, from the most general
18370 template. */
18371 tree args;
18372 tree code_pattern;
18377 /* Make sure that we can see identifiers, and compute access
18378 correctly. */
18382 {
18383 tree decl_parm;
18384 tree pattern_parm;
18385 tree specs;
18399 specs);
18401 /* Merge parameter declarations. */
18404 pattern_parm
18408 {
18409 tree parm_type;
18410 tree attributes;
18415 NULL_TREE);
18421 {
18424 }
18427 }
18428 /* Merge any parameters that match with the function parameter
18429 pack. */
18431 {
18433 tree expanded_types;
18434 /* Expand the TYPE_PACK_EXPANSION that provides the types for
18435 the parameters in this function parameter pack. */
18440 {
18441 tree parm_type;
18442 tree attributes;
18445 /* Rename the parameter to include the index. */
18454 {
18457 }
18459 }
18460 }
18461 /* Merge additional specifiers from the CODE_PATTERN. */
18465 }
18467 {
18475 }
18476 else
18480 }
18482 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
18483 substituted to get DECL. */
18485 tree
18487 {
18490 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
18491 for the instantiation. This is not always the most general
18492 template. Consider, for example:
18494 template <class T>
18495 struct S { template <class U> void f();
18496 template <> void f<int>(); };
18498 and an instantiation of S<double>::f<int>. We want TD to be the
18499 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
18501 more general template. */
18503 /* We must also deal with friend templates. Given:
18505 template <class T> struct S {
18506 template <class U> friend void f() {};
18507 };
18509 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
18510 so far as the language is concerned, but that's still
18511 where we get the pattern for the instantiation from. On
18512 other hand, if the definition comes outside the class, say:
18514 template <class T> struct S {
18515 template <class U> friend void f();
18516 };
18517 template <class U> friend void f() {}
18519 we don't need to look any further. That's what the check for
18520 DECL_INITIAL is for. */
18524 {
18525 /* The present template, TD, should not be a definition. If it
18526 were a definition, we should be using it! Note that we
18527 cannot restructure the loop to just keep going until we find
18528 a template with a definition, since that might go too far if
18529 a specialization was declared, but not defined. */
18533 /* Fetch the more general template. */
18535 }
18538 }
18540 /* Returns true if we need to instantiate this template instance even if we
18541 know we aren't going to emit it.. */
18543 bool
18545 {
18546 /* We always instantiate inline functions so that we can inline them. An
18547 explicit instantiation declaration prohibits implicit instantiation of
18548 non-inline functions. With high levels of optimization, we would
18549 normally inline non-inline functions -- but we're not allowed to do
18550 that for "extern template" functions. Therefore, we check
18551 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
18555 /* And we need to instantiate static data members so that
18556 their initializers are available in integral constant
18557 expressions. */
18560 }
18562 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
18563 instantiate it now, modifying TREE_TYPE (fn). */
18565 void
18567 {
18581 {
18583 {
18598 }
18599 else
18601 }
18602 else
18603 {
18604 /* This is an implicitly declared function, so NOEX is a list of
18605 other functions to evaluate and merge. */
18606 tree elt;
18609 {
18611 tree subspec;
18615 }
18616 }
18621 {
18624 else
18626 }
18627 }
18629 /* Produce the definition of D, a _DECL generated from a template. If
18630 DEFER_OK is nonzero, then we don't have to actually do the
18631 instantiation now; we just have to do it sometime. Normally it is
18632 an error if this is an explicit instantiation but D is undefined.
18633 EXPL_INST_CLASS_MEM_P is true iff D is a member of an
18634 explicitly instantiated class template. */
18636 tree
18639 {
18641 tree gen_args;
18642 tree args;
18643 tree td;
18644 tree code_pattern;
18645 tree spec;
18646 tree gen_tmpl;
18650 tree fn_context;
18653 /* This function should only be used to instantiate templates for
18654 functions and static member variables. */
18658 /* Variables are never deferred; if instantiation is required, they
18659 are instantiated right away. That allows for better code in the
18660 case that an expression refers to the value of the variable --
18661 if the variable has a constant value the referring expression can
18662 take advantage of that fact. */
18667 /* Don't instantiate cloned functions. Instead, instantiate the
18668 functions they cloned. */
18676 /* D has already been instantiated or explicitly specialized, so
18677 there's nothing for us to do here.
18679 It might seem reasonable to check whether or not D is an explicit
18680 instantiation, and, if so, stop here. But when an explicit
18681 instantiation is deferred until the end of the compilation,
18682 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
18683 the instantiation. */
18686 /* Check to see whether we know that this template will be
18687 instantiated in some other file, as with "extern template"
18688 extension. */
18691 /* In general, we do not instantiate such templates. */
18699 /* We should already have the extra args. */
18702 /* And what's in the hash table should match D. */
18706 /* This needs to happen before any tsubsting. */
18712 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
18713 for the instantiation. */
18717 /* We should never be trying to instantiate a member of a class
18718 template or partial specialization. */
18723 /* In the case of a friend template whose definition is provided
18724 outside the class, we may have too many arguments. Drop the
18725 ones we don't need. The same is true for specializations. */
18726 args = get_innermost_template_args
18728 else
18734 else
18737 /* We may be in the middle of deferred access check. Disable it now. */
18740 /* Unless an explicit instantiation directive has already determined
18741 the linkage of D, remember that a definition is available for
18742 this entity. */
18752 /* If D is a member of an explicitly instantiated class template,
18753 and no definition is available, treat it like an implicit
18754 instantiation. */
18757 {
18758 /* Leave linkage flags alone on instantiations with anonymous
18759 visibility. */
18761 {
18764 }
18766 }
18771 /* Defer all other templates, unless we have been explicitly
18772 forbidden from doing so. */
18774 template. */
18775 ! pattern_defined
18776 /* If it's OK to postpone instantiation, do so. */
18777 || defer_ok
18778 /* If this is a static data member that will be defined
18779 elsewhere, we don't want to instantiate the entire data
18780 member, but we do want to instantiate the initializer so that
18781 we can substitute that elsewhere. */
18783 {
18784 /* The definition of the static data member is now required so
18785 we must substitute the initializer. */
18789 {
18790 tree ns;
18791 tree init;
18798 args,
18801 /* Make sure the initializer is still constant, in case of
18802 circular dependency (template/instantiate6.C). */
18803 const_init
18807 LOOKUP_ONLYCONVERTING);
18810 }
18812 /* We restore the source position here because it's used by
18813 add_pending_template. */
18819 /* [temp.explicit]
18821 The definition of a non-exported function template, a
18822 non-exported member function template, or a non-exported
18823 member function or static data member of a class template
18824 shall be present in every translation unit in which it is
18825 explicitly instantiated. */
18829 /* If we're in unevaluated context, we just wanted to get the
18830 constant value; this isn't an odr use, so don't queue
18831 a full instantiation. */
18834 /* ??? Historically, we have instantiated inline functions, even
18835 when marked as "extern template". */
18839 }
18840 /* Tell the repository that D is available in this translation unit
18841 -- and see if it is supposed to be instantiated here. */
18843 {
18844 /* In a PCH file, despite the fact that the repository hasn't
18845 requested instantiation in the PCH it is still possible that
18846 an instantiation will be required in a file that includes the
18847 PCH. */
18850 /* Instantiate inline functions so that the inliner can do its
18851 job, even though we'll not be emitting a copy of this
18852 function. */
18855 }
18864 /* Mark D as instantiated so that recursive calls to
18865 instantiate_decl do not try to instantiate it again. */
18868 /* Regenerate the declaration in case the template has been modified
18869 by a subsequent redeclaration. */
18872 /* We already set the file and line above. Reset them now in case
18873 they changed as a result of calling regenerate_decl_from_template. */
18877 {
18878 tree init;
18881 /* Clear out DECL_RTL; whatever was there before may not be right
18882 since we've reset the type of the declaration. */
18886 /* The initializer is placed in DECL_INITIAL by
18887 regenerate_decl_from_template so we don't need to
18888 push/pop_access_scope again here. Pull it out so that
18889 cp_finish_decl can process it. */
18894 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
18895 initializer. That function will defer actual emission until
18896 we have a chance to determine linkage. */
18899 /* Enter the scope of D so that access-checking works correctly. */
18904 }
18908 {
18910 tree subst_decl;
18911 tree tmpl_parm;
18912 tree spec_parm;
18914 /* Save away the current list, in case we are instantiating one
18915 template from within the body of another. */
18918 /* Set up the list of local specializations. */
18921 /* Set up context. */
18924 /* Some typedefs referenced from within the template code need to be
18925 access checked at template instantiation time, i.e now. These
18926 types were added to the template at parsing time. Let's get those
18927 and perform the access checks then. */
18929 gen_args);
18931 /* Create substitution entries for the parameters. */
18936 {
18940 }
18942 {
18944 {
18947 }
18948 else
18949 {
18950 /* Register the (value) argument pack as a specialization of
18951 TMPL_PARM, then move on. */
18954 }
18955 }
18958 /* Substitute into the body of the function. */
18963 /* Set the current input_location to the end of the function
18964 so that finish_function knows where we are. */
18967 /* We don't need the local specializations any more. */
18971 /* Finish the function. */
18974 }
18976 /* We're not deferring instantiation any more. */
18984 out:
18992 }
18994 /* Run through the list of templates that we wish we could
18995 instantiate, and instantiate any we can. RETRIES is the
18996 number of times we retry pending template instantiation. */
18998 void
19000 {
19004 /* Instantiating templates may trigger vtable generation. This in turn
19005 may require further template instantiations. We place a limit here
19006 to avoid infinite loop. */
19008 {
19012 " instantiating %q+D, possibly from virtual table generation"
19016 /* Pretend that we defined it. */
19019 }
19021 do
19022 {
19027 {
19032 {
19033 tree fn;
19036 {
19040 fn;
19048 }
19051 }
19052 else
19053 {
19056 {
19057 instantiation
19063 }
19067 }
19070 /* If INSTANTIATION has been instantiated, then we don't
19071 need to consider it again in the future. */
19073 else
19074 {
19077 }
19080 }
19082 }
19086 }
19088 /* Substitute ARGVEC into T, which is a list of initializers for
19089 either base class or a non-static data member. The TREE_PURPOSEs
19090 are DECLs, and the TREE_VALUEs are the initializer values. Used by
19091 instantiate_decl. */
19093 static tree
19095 {
19099 {
19100 tree decl;
19101 tree init;
19107 {
19108 tree expr;
19109 tree arg;
19111 /* Expand the base class expansion type into separate base
19112 classes. */
19114 tf_warning_or_error,
19115 NULL_TREE);
19119 /* We'll be building separate TREE_LISTs of arguments for
19120 each base. */
19126 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
19127 expand each argument in the TREE_VALUE of t. */
19134 /* VOID_TYPE_NODE is used to indicate
19135 value-initialization. */
19136 {
19139 }
19140 else
19141 {
19142 /* Substitute parameter packs into each argument in the
19143 TREE_LIST. */
19146 {
19147 tree expanded_exprs;
19149 /* Expand the argument. */
19151 expanded_exprs
19153 tf_warning_or_error,
19154 NULL_TREE);
19158 /* Prepend each of the expanded expressions to the
19159 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
19161 {
19166 }
19167 }
19170 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
19171 since we built them backwards. */
19173 {
19176 }
19177 }
19178 }
19181 {
19183 {
19187 }
19188 else
19189 {
19190 tree tmp;
19205 /* If we had an initializer but it instantiated to nothing,
19206 value-initialize the object. This will only occur when
19207 the initializer was a pack expansion where the parameter
19208 packs used in that expansion were of length zero. */
19211 }
19214 {
19218 }
19219 }
19220 }
19222 }
19224 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
19226 static void
19228 {
19233 else
19235 }
19237 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
19238 is the instantiation (which should have been created with
19239 start_enum) and ARGS are the template arguments to use. */
19241 static void
19243 {
19244 tree e;
19250 {
19251 tree value;
19252 tree decl;
19255 /* Note that in a template enum, the TREE_VALUE is the
19256 CONST_DECL, not the corresponding INTEGER_CST. */
19261 /* Give this enumeration constant the correct access. */
19264 /* Actually build the enumerator itself. */
19265 build_enumerator
19267 }
19277 }
19279 /* DECL is a FUNCTION_DECL that is a template specialization. Return
19280 its type -- but without substituting the innermost set of template
19281 arguments. So, innermost set of template parameters will appear in
19282 the type. */
19284 tree
19286 {
19287 tree fn_type;
19288 tree tmpl;
19289 tree targs;
19290 tree tparms;
19298 /* There should be as many levels of arguments as there are levels
19299 of parameters. */
19305 /* No substitution is necessary. */
19306 ;
19307 else
19308 {
19310 tree partial_args;
19312 /* Replace the innermost level of the TARGS with NULL_TREEs to
19313 let tsubst know not to substitute for those parameters. */
19322 /* Make sure that we can see identifiers, and compute access
19323 correctly. */
19327 /* Now, do the (partial) substitution to figure out the
19328 appropriate function type. */
19332 /* Substitute into the template parameters to obtain the real
19333 innermost set of parameters. This step is important if the
19334 innermost set of template parameters contains value
19335 parameters whose types depend on outer template parameters. */
19340 }
19343 }
19345 /* Return truthvalue if we're processing a template different from
19346 the last one involved in diagnostics. */
19347 int
19349 {
19351 }
19353 /* Remember current template involved in diagnostics. */
19354 void
19356 {
19358 }
19362 {
19364 }
19366 /* [temp.param] Check that template non-type parm TYPE is of an allowable
19367 type. Return zero for ok, nonzero for disallowed. Issue error and
19368 warning messages under control of COMPLAIN. */
19370 static int
19372 {
19389 {
19392 else
19394 type);
19395 }
19397 }
19399 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
19400 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
19402 static bool
19404 {
19405 tree scope;
19407 /* [temp.dep.type]
19409 A type is dependent if it is:
19411 -- a template parameter. Template template parameters are types
19412 for us (since TYPE_P holds true for them) so we handle
19413 them here. */
19417 /* -- a qualified-id with a nested-name-specifier which contains a
19418 class-name that names a dependent type or whose unqualified-id
19419 names a dependent type. */
19422 /* -- a cv-qualified type where the cv-unqualified type is
19423 dependent. */
19425 /* -- a compound type constructed from any dependent type. */
19435 {
19436 tree arg_type;
19441 arg_type;
19446 }
19447 /* -- an array type constructed from any dependent type or whose
19448 size is specified by a constant expression that is
19449 value-dependent.
19451 We checked for type- and value-dependence of the bounds in
19452 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
19454 {
19459 }
19461 /* -- a template-id in which either the template name is a template
19462 parameter ... */
19465 /* ... or any of the template arguments is a dependent type or
19466 an expression that is type-dependent or value-dependent. */
19468 && (any_dependent_template_arguments_p
19472 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
19473 dependent; if the argument of the `typeof' expression is not
19474 type-dependent, then it should already been have resolved. */
19480 /* A template argument pack is dependent if any of its packed
19481 arguments are. */
19483 {
19489 }
19491 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
19492 be template parameters. */
19496 /* The standard does not specifically mention types that are local
19497 to template functions or local classes, but they should be
19498 considered dependent too. For example:
19500 template <int I> void f() {
19501 enum E { a = I };
19502 S<sizeof (E)> s;
19503 }
19505 The size of `E' cannot be known until the value of `I' has been
19506 determined. Therefore, `E' must be considered dependent. */
19510 /* Don't use type_dependent_expression_p here, as it can lead
19511 to infinite recursion trying to determine whether a lambda
19512 nested in a lambda is dependent (c++/47687). */
19516 && (any_dependent_template_arguments_p
19520 /* Other types are non-dependent. */
19522 }
19524 /* Returns TRUE if TYPE is dependent, in the sense of
19525 [temp.dep.type]. Note that a NULL type is considered dependent. */
19527 bool
19529 {
19530 /* If there are no template parameters in scope, then there can't be
19531 any dependent types. */
19533 {
19534 /* If we are not processing a template, then nobody should be
19535 providing us with a dependent type. */
19539 }
19541 /* If the type is NULL, we have not computed a type for the entity
19542 in question; in that case, the type is dependent. */
19546 /* Erroneous types can be considered non-dependent. */
19550 /* If we have not already computed the appropriate value for TYPE,
19551 do so now. */
19553 {
19556 }
19559 }
19561 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
19562 lookup. In other words, a dependent type that is not the current
19563 instantiation. */
19565 bool
19567 {
19570 }
19572 /* T is a SCOPE_REF; return whether we need to consider it
19573 instantiation-dependent so that we can check access at instantiation
19574 time even though we know which member it resolves to. */
19576 static bool
19578 {
19584 else
19586 }
19588 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
19589 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
19590 expression. */
19592 /* Note that this predicate is not appropriate for general expressions;
19593 only constant expressions (that satisfy potential_constant_expression)
19594 can be tested for value dependence. */
19596 bool
19598 {
19602 /* A name declared with a dependent type. */
19607 {
19609 /* A name that has not been looked up -- must be dependent. */
19613 /* A non-type template parm. */
19617 /* A non-type template parm. */
19623 /* A constant with literal type and is initialized
19624 with an expression that is value-dependent.
19626 Note that a non-dependent parenthesized initializer will have
19627 already been replaced with its constant value, so if we see
19628 a TREE_LIST it must be dependent. */
19641 /* These expressions are value-dependent if the type to which
19642 the cast occurs is dependent or the expression being casted
19643 is value-dependent. */
19644 {
19650 /* A functional cast has a list of operands. */
19653 {
19654 /* If there are no operands, it must be an expression such
19655 as "int()". This should not happen for aggregate types
19656 because it would form non-constant expressions. */
19661 }
19667 }
19672 /* FALLTHRU */
19675 /* A `sizeof' expression is value-dependent if the operand is
19676 type-dependent or is a pack expansion. */
19685 /* An 'encode' expression is value-dependent if the operand is
19686 type-dependent. */
19695 /* All instantiation-dependent expressions should also be considered
19696 value-dependent. */
19704 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
19705 is value-dependent. */
19706 {
19715 }
19718 {
19722 }
19733 {
19737 }
19740 {
19747 {
19749 /* In a call to a constexpr member function, look through the
19750 implicit ADDR_EXPR on the object argument so that it doesn't
19751 cause the call to be considered value-dependent. We also
19752 look through it in potential_constant_expression. */
19759 }
19761 }
19764 /* If a TEMPLATE_ID_EXPR involves a dependent name, it will be
19765 type-dependent. */
19769 {
19771 tree val;
19776 }
19779 /* Treat a GNU statement expression as dependent to avoid crashing
19780 under fold_non_dependent_expr; it can't be constant. */
19784 /* A constant expression is value-dependent if any subexpression is
19785 value-dependent. */
19787 {
19794 {
19798 {
19801 /* In some cases, some of the operands may be missing.l
19802 (For example, in the case of PREDECREMENT_EXPR, the
19803 amount to increment by may be missing.) That doesn't
19804 make the expression dependent. */
19807 }
19808 }
19812 }
19814 }
19816 /* The expression is not value-dependent. */
19818 }
19820 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
19821 [temp.dep.expr]. Note that an expression with no type is
19822 considered dependent. Other parts of the compiler arrange for an
19823 expression with type-dependent subexpressions to have no type, so
19824 this function doesn't have to be fully recursive. */
19826 bool
19828 {
19835 /* An unresolved name is always dependent. */
19840 /* Some expression forms are never type-dependent. */
19853 /* The types of these expressions depends only on the type to which
19854 the cast occurs. */
19863 /* The types of these expressions depends only on the type created
19864 by the expression. */
19867 {
19868 /* For NEW_EXPR tree nodes created inside a template, either
19869 the object type itself or a TREE_LIST may appear as the
19870 operand 1. */
19873 /* This is an array type. We need to check array dimensions
19874 as well. */
19876 || value_dependent_expression_p
19878 else
19880 }
19883 {
19887 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
19888 contains an identifier associated by name lookup with one or more
19889 declarations declared with a dependent type, or...a
19890 nested-name-specifier or qualified-id that names a member of an
19891 unknown specialization. */
19894 }
19899 && (any_dependent_template_arguments_p
19911 {
19912 tree elt;
19916 {
19919 }
19921 }
19923 /* A static data member of the current instantiation with incomplete
19924 array type is type-dependent, as the definition and specializations
19925 can have different bounds. */
19932 /* An array of unknown bound depending on a variadic parameter, eg:
19934 template<typename... Args>
19935 void foo (Args... args)
19936 {
19937 int arr[] = { args... };
19938 }
19940 template<int... vals>
19941 void bar ()
19942 {
19943 int arr[] = { vals... };
19944 }
19946 If the array has no length and has an initializer, it must be that
19947 we couldn't determine its length in cp_complete_array_type because
19948 it is dependent. */
19956 {
19961 {
19967 }
19968 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
19972 /* Always dependent, on the number of arguments if nothing else. */
19980 {
19985 }
19990 {
19994 }
19996 }
20001 }
20003 /* walk_tree callback function for instantiation_dependent_expression_p,
20004 below. Returns non-zero if a dependent subexpression is found. */
20006 static tree
20009 {
20011 {
20012 /* We don't have to worry about decltype currently because decltype
20013 of an instantiation-dependent expr is a dependent type. This
20014 might change depending on the resolution of DR 1172. */
20017 }
20020 {
20021 /* Don't treat an argument list as dependent just because it has no
20022 TREE_TYPE. */
20030 /* Handle expressions with type operands. */
20035 {
20040 {
20043 else
20044 {
20047 }
20048 }
20050 }
20062 /* In a template, finish_class_member_access_expr creates a
20063 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
20064 type-dependent, so that we can check access control at
20065 instantiation time (PR 42277). See also Core issue 1273. */
20072 else
20075 /* Treat statement-expressions as dependent. */
20081 }
20085 else
20087 }
20089 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
20090 sense defined by the ABI:
20092 "An expression is instantiation-dependent if it is type-dependent
20093 or value-dependent, or it has a subexpression that is type-dependent
20094 or value-dependent." */
20096 bool
20098 {
20099 tree result;
20110 }
20112 /* Like type_dependent_expression_p, but it also works while not processing
20113 a template definition, i.e. during substitution or mangling. */
20115 bool
20117 {
20123 }
20125 /* Returns TRUE if ARGS contains a type-dependent expression. */
20127 bool
20129 {
20131 tree arg;
20134 {
20137 }
20139 }
20141 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
20142 expressions) contains any type-dependent expressions. */
20144 bool
20146 {
20152 }
20154 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
20155 expressions) contains any value-dependent expressions. */
20157 bool
20159 {
20165 }
20167 /* Returns TRUE if the ARG (a template argument) is dependent. */
20169 bool
20171 {
20175 /* Assume a template argument that was wrongly written by the user
20176 is dependent. This is consistent with what
20177 any_dependent_template_arguments_p [that calls this function]
20178 does. */
20189 {
20193 {
20196 }
20199 }
20202 else
20205 }
20207 /* Returns true if ARGS (a collection of template arguments) contains
20208 any types that require structural equality testing. */
20210 bool
20212 {
20222 {
20225 {
20231 {
20232 /* Look inside the argument pack. */
20235 }
20238 {
20252 }
20253 }
20254 }
20257 }
20259 /* Returns true if ARGS (a collection of template arguments) contains
20260 any dependent arguments. */
20262 bool
20264 {
20274 {
20279 }
20282 }
20284 /* Returns TRUE if the template TMPL is dependent. */
20286 bool
20288 {
20290 {
20292 {
20296 }
20298 }
20300 /* Template template parameters are dependent. */
20304 /* So are names that have not been looked up. */
20308 /* So are member templates of dependent classes. */
20312 }
20314 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
20316 bool
20318 {
20321 }
20323 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
20324 is dependent. */
20326 bool
20328 {
20335 {
20356 {
20360 }
20364 {
20368 {
20373 }
20374 }
20375 }
20378 }
20380 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
20381 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
20382 no such TYPE can be found. Note that this function peers inside
20383 uninstantiated templates and therefore should be used only in
20384 extremely limited situations. ONLY_CURRENT_P restricts this
20385 peering to the currently open classes hierarchy (which is required
20386 when comparing types). */
20388 tree
20390 {
20391 tree scope;
20392 tree name;
20393 tree decl;
20395 tree pushed_scope;
20396 tree result;
20401 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
20402 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
20403 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
20404 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
20405 identifier of the TYPENAME_TYPE anymore.
20406 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
20407 TYPENAME_TYPE instead, we avoid messing up with a possible
20408 typedef variant case. */
20411 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
20412 it first before we can figure out what NAME refers to. */
20414 {
20416 /* Given a class template A with a dependent base with nested type C,
20417 typedef typename A::C::C C will land us here, as trying to resolve
20418 the initial A::C leads to the local C typedef, which leads back to
20419 A::C::C. So we break the recursion now. */
20421 else
20423 }
20424 /* If we don't know what SCOPE refers to, then we cannot resolve the
20425 TYPENAME_TYPE. */
20428 /* If the SCOPE is a template type parameter, we have no way of
20429 resolving the name. */
20432 /* If the SCOPE is not the current instantiation, there's no reason
20433 to look inside it. */
20436 /* If this is a typedef, we don't want to look inside (c++/11987). */
20439 /* If SCOPE isn't the template itself, it will not have a valid
20440 TYPE_FIELDS list. */
20442 /* scope is either the template itself or a compatible instantiation
20443 like X<T>, so look up the name in the original template. */
20445 else
20446 /* scope is a partial instantiation, so we can't do the lookup or we
20447 will lose the template arguments. */
20449 /* Enter the SCOPE so that name lookup will be resolved as if we
20450 were in the class definition. In particular, SCOPE will no
20451 longer be considered a dependent type. */
20453 /* Look up the declaration. */
20455 tf_warning_or_error);
20459 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
20460 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
20465 {
20469 }
20472 {
20473 tree tmpl;
20474 tree args;
20475 /* Obtain the template and the arguments. */
20478 /* Instantiate the template. */
20484 }
20486 /* Leave the SCOPE. */
20490 /* If we failed to resolve it, return the original typename. */
20494 /* If lookup found a typename type, resolve that too. */
20496 {
20497 /* Ill-formed programs can cause infinite recursion here, so we
20498 must catch that. */
20502 }
20504 /* Qualify the resulting type. */
20510 }
20512 /* EXPR is an expression which is not type-dependent. Return a proxy
20513 for EXPR that can be used to compute the types of larger
20514 expressions containing EXPR. */
20516 tree
20518 {
20519 tree inner_expr;
20521 #ifdef ENABLE_CHECKING
20522 /* Try to get a constant value for all non-dependent expressions in
20523 order to expose bugs in *_dependent_expression_p and constexpr. */
20527 #endif
20529 /* Preserve OVERLOADs; the functions must be available to resolve
20530 types. */
20541 /* There is no need to return a proxy for a variable. */
20544 /* Preserve string constants; conversions from string constants to
20545 "char *" are allowed, even though normally a "const char *"
20546 cannot be used to initialize a "char *". */
20549 /* Preserve arithmetic constants, as an optimization -- there is no
20550 reason to create a new node. */
20553 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
20554 There is at least one place where we want to know that a
20555 particular expression is a throw-expression: when checking a ?:
20556 expression, there are special rules if the second or third
20557 argument is a throw-expression. */
20561 /* Don't wrap an initializer list, we need to be able to look inside. */
20565 /* Don't wrap a dummy object, we need to be able to test for it. */
20584 /* If the type is unknown, it can't really be non-dependent */
20587 /* Otherwise, build a NON_DEPENDENT_EXPR. */
20589 }
20591 /* ARGS is a vector of expressions as arguments to a function call.
20592 Replace the arguments with equivalent non-dependent expressions.
20593 This modifies ARGS in place. */
20595 void
20597 {
20599 tree arg;
20602 {
20606 }
20607 }
20609 /* Returns a type which represents 'auto'. We use a TEMPLATE_TYPE_PARM
20610 with a level one deeper than the actual template parms. */
20612 tree
20614 {
20627 }
20629 /* Given type ARG, return std::initializer_list<ARG>. */
20631 static tree
20633 {
20634 tree std_init_list = namespace_binding
20636 tree argvec;
20638 {
20642 }
20647 }
20649 /* Replace auto in TYPE with std::initializer_list<auto>. */
20651 static tree
20653 {
20660 }
20662 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
20663 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
20665 tree
20667 {
20676 /* Defining a subset of type-dependent expressions that we can deduce
20677 from ahead of time isn't worth the trouble. */
20680 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
20681 with either a new invented type template parameter U or, if the
20682 initializer is a braced-init-list (8.5.4), with
20683 std::initializer_list<U>. */
20699 {
20701 /* Try again at instantiation time. */
20704 /* If type is error_mark_node a diagnostic must have been
20705 emitted by now. Also, having a mention to '<type error>'
20706 in the diagnostic is not really useful to the user. */
20707 {
20711 else
20713 }
20715 }
20717 /* If the list of declarators contains more than one declarator, the type
20718 of each declared variable is determined as described above. If the
20719 type deduced for the template parameter U is not the same in each
20720 deduction, the program is ill-formed. */
20723 {
20729 else
20733 }
20739 }
20741 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
20742 result. */
20744 tree
20746 {
20747 tree argvec;
20754 /* For a late-specified return type in a template type-parameter, we
20755 need to add a dummy argument level for its parmlist. */
20756 argvec = add_to_template_args
20761 }
20763 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto'. */
20765 bool
20767 {
20771 else
20773 }
20775 /* Returns true iff TYPE contains a use of 'auto'. Since auto can only
20776 appear as a type-specifier for the declaration in question, we don't
20777 have to look through the whole type. */
20779 tree
20781 {
20798 }
20800 /* For a given template T, return the vector of typedefs referenced
20801 in T for which access check is needed at T instantiation time.
20802 T is either a FUNCTION_DECL or a RECORD_TYPE.
20803 Those typedefs were added to T by the function
20804 append_type_to_template_for_access_check. */
20808 {
20809 tree ti;
20820 {
20825 }
20828 }
20830 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
20831 tied to T. That list of typedefs will be access checked at
20832 T instantiation time.
20833 T is either a FUNCTION_DECL or a RECORD_TYPE.
20834 TYPE_DECL is a TYPE_DECL node representing a typedef.
20835 SCOPE is the scope through which TYPE_DECL is accessed.
20836 LOCATION is the location of the usage point of TYPE_DECL.
20838 This function is a subroutine of
20839 append_type_to_template_for_access_check. */
20841 static void
20843 tree type_decl,
20844 tree scope,
20845 location_t location)
20846 {
20847 qualified_typedef_usage_t typedef_usage;
20848 tree ti;
20855 && type_decl
20869 }
20871 /* Append TYPE_DECL to the template TEMPL.
20872 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
20873 At TEMPL instanciation time, TYPE_DECL will be checked to see
20874 if it can be accessed through SCOPE.
20875 LOCATION is the location of the usage point of TYPE_DECL.
20877 e.g. consider the following code snippet:
20879 class C
20880 {
20881 typedef int myint;
20882 };
20884 template<class U> struct S
20885 {
20886 C::myint mi; // <-- usage point of the typedef C::myint
20887 };
20889 S<char> s;
20891 At S<char> instantiation time, we need to check the access of C::myint
20892 In other words, we need to check the access of the myint typedef through
20893 the C scope. For that purpose, this function will add the myint typedef
20894 and the scope C through which its being accessed to a list of typedefs
20895 tied to the template S. That list will be walked at template instantiation
20896 time and access check performed on each typedefs it contains.
20897 Note that this particular code snippet should yield an error because
20898 myint is private to C. */
20900 void
20902 tree type_decl,
20903 tree scope,
20904 location_t location)
20905 {
20911 /* Make sure we don't append the type to the template twice. */
20918 }
20920 /* Set up the hash tables for template instantiations. */
20922 void
20924 {
20926 hash_specialization,
20927 eq_specializations,
20928 ggc_free);
20930 hash_specialization,
20931 eq_specializations,
20932 ggc_free);
20933 }
20935 /* Print stats about the template hash tables for -fstats. */
20937 void
20939 {
20948 }