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/* Handle parameterized types (templates) for GNU C++. Copyright (C) 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009 Free Software Foundation, Inc. Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing. Rewritten by Jason Merrill (jason@cygnus.com). This file is part of GCC. GCC is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3, or (at your option) any later version. GCC is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GCC; see the file COPYING3. If not see <http://www.gnu.org/licenses/>. */ /* Known bugs or deficiencies include: all methods must be provided in header files; can't use a source file that contains only the method templates and "just win". */ #include "config.h" #include "system.h" #include "coretypes.h" #include "tm.h" #include "obstack.h" #include "tree.h" #include "intl.h" #include "pointer-set.h" #include "flags.h" #include "c-common.h" #include "cp-tree.h" #include "cp-objcp-common.h" #include "tree-inline.h" #include "decl.h" #include "output.h" #include "except.h" #include "toplev.h" #include "rtl.h" #include "timevar.h" #include "tree-iterator.h" #include "vecprim.h" /* The type of functions taking a tree, and some additional data, and returning an int. */ typedef int (*tree_fn_t) (tree, void*); /* The PENDING_TEMPLATES is a TREE_LIST of templates whose instantiations have been deferred, either because their definitions were not yet available, or because we were putting off doing the work. */ struct GTY (()) pending_template { struct pending_template *next; struct tinst_level *tinst; }; static GTY(()) struct pending_template *pending_templates; static GTY(()) struct pending_template *last_pending_template; int processing_template_parmlist; static int template_header_count; static GTY(()) tree saved_trees; static VEC(int,heap) *inline_parm_levels; static GTY(()) struct tinst_level *current_tinst_level; static GTY(()) tree saved_access_scope; /* Live only within one (recursive) call to tsubst_expr. We use this to pass the statement expression node from the STMT_EXPR to the EXPR_STMT that is its result. */ static tree cur_stmt_expr; /* A map from local variable declarations in the body of the template presently being instantiated to the corresponding instantiated local variables. */ static htab_t local_specializations; typedef struct GTY(()) spec_entry { tree tmpl; tree args; tree spec; } spec_entry; static GTY ((param_is (spec_entry))) htab_t decl_specializations; static GTY ((param_is (spec_entry))) htab_t type_specializations; /* Contains canonical template parameter types. The vector is indexed by the TEMPLATE_TYPE_IDX of the template parameter. Each element is a TREE_LIST, whose TREE_VALUEs contain the canonical template parameters of various types and levels. */ static GTY(()) VEC(tree,gc) *canonical_template_parms; #define UNIFY_ALLOW_NONE 0 #define UNIFY_ALLOW_MORE_CV_QUAL 1 #define UNIFY_ALLOW_LESS_CV_QUAL 2 #define UNIFY_ALLOW_DERIVED 4 #define UNIFY_ALLOW_INTEGER 8 #define UNIFY_ALLOW_OUTER_LEVEL 16 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64 static void push_access_scope (tree); static void pop_access_scope (tree); static bool resolve_overloaded_unification (tree, tree, tree, tree, unification_kind_t, int); static int try_one_overload (tree, tree, tree, tree, tree, unification_kind_t, int, bool); static int unify (tree, tree, tree, tree, int); static void add_pending_template (tree); static tree reopen_tinst_level (struct tinst_level *); static tree tsubst_initializer_list (tree, tree); static tree get_class_bindings (tree, tree, tree); static tree coerce_template_parms (tree, tree, tree, tsubst_flags_t, bool, bool); static void tsubst_enum (tree, tree, tree); static tree add_to_template_args (tree, tree); static tree add_outermost_template_args (tree, tree); static bool check_instantiated_args (tree, tree, tsubst_flags_t); static int maybe_adjust_types_for_deduction (unification_kind_t, tree*, tree*, tree); static int type_unification_real (tree, tree, tree, const tree *, unsigned int, int, unification_kind_t, int); static void note_template_header (int); static tree convert_nontype_argument_function (tree, tree); static tree convert_nontype_argument (tree, tree); static tree convert_template_argument (tree, tree, tree, tsubst_flags_t, int, tree); static int for_each_template_parm (tree, tree_fn_t, void*, struct pointer_set_t*, bool); static tree expand_template_argument_pack (tree); static tree build_template_parm_index (int, int, int, tree, tree); static bool inline_needs_template_parms (tree); static void push_inline_template_parms_recursive (tree, int); static tree retrieve_local_specialization (tree); static void register_local_specialization (tree, tree); static hashval_t hash_specialization (const void *p); static tree reduce_template_parm_level (tree, tree, int, tree, tsubst_flags_t); static int mark_template_parm (tree, void *); static int template_parm_this_level_p (tree, void *); static tree tsubst_friend_function (tree, tree); static tree tsubst_friend_class (tree, tree); static int can_complete_type_without_circularity (tree); static tree get_bindings (tree, tree, tree, bool); static int template_decl_level (tree); static int check_cv_quals_for_unify (int, tree, tree); static void template_parm_level_and_index (tree, int*, int*); static int unify_pack_expansion (tree, tree, tree, tree, int, bool, bool); static tree tsubst_template_arg (tree, tree, tsubst_flags_t, tree); static tree tsubst_template_args (tree, tree, tsubst_flags_t, tree); static tree tsubst_template_parms (tree, tree, tsubst_flags_t); static void regenerate_decl_from_template (tree, tree); static tree most_specialized_class (tree, tree); static tree tsubst_aggr_type (tree, tree, tsubst_flags_t, tree, int); static tree tsubst_arg_types (tree, tree, tsubst_flags_t, tree); static tree tsubst_function_type (tree, tree, tsubst_flags_t, tree); static bool check_specialization_scope (void); static tree process_partial_specialization (tree); static void set_current_access_from_decl (tree); static tree get_template_base (tree, tree, tree, tree); static tree try_class_unification (tree, tree, tree, tree); static int coerce_template_template_parms (tree, tree, tsubst_flags_t, tree, tree); static bool template_template_parm_bindings_ok_p (tree, tree); static int template_args_equal (tree, tree); static void tsubst_default_arguments (tree); static tree for_each_template_parm_r (tree *, int *, void *); static tree copy_default_args_to_explicit_spec_1 (tree, tree); static void copy_default_args_to_explicit_spec (tree); static int invalid_nontype_parm_type_p (tree, tsubst_flags_t); static int eq_local_specializations (const void *, const void *); static bool dependent_template_arg_p (tree); static bool any_template_arguments_need_structural_equality_p (tree); static bool dependent_type_p_r (tree); static tree tsubst_expr (tree, tree, tsubst_flags_t, tree, bool); static tree tsubst_copy (tree, tree, tsubst_flags_t, tree); static tree tsubst_pack_expansion (tree, tree, tsubst_flags_t, tree); static tree tsubst_decl (tree, tree, tsubst_flags_t); static void perform_typedefs_access_check (tree tmpl, tree targs); static void append_type_to_template_for_access_check_1 (tree, tree, tree, location_t); static hashval_t iterative_hash_template_arg (tree arg, hashval_t val); static tree listify (tree); static tree listify_autos (tree, tree); /* Make the current scope suitable for access checking when we are processing T. T can be FUNCTION_DECL for instantiated function template, or VAR_DECL for static member variable (need by instantiate_decl). */ static void push_access_scope (tree t) { gcc_assert (TREE_CODE (t) == FUNCTION_DECL || TREE_CODE (t) == VAR_DECL); if (DECL_FRIEND_CONTEXT (t)) push_nested_class (DECL_FRIEND_CONTEXT (t)); else if (DECL_CLASS_SCOPE_P (t)) push_nested_class (DECL_CONTEXT (t)); else push_to_top_level (); if (TREE_CODE (t) == FUNCTION_DECL) { saved_access_scope = tree_cons (NULL_TREE, current_function_decl, saved_access_scope); current_function_decl = t; } } /* Restore the scope set up by push_access_scope. T is the node we are processing. */ static void pop_access_scope (tree t) { if (TREE_CODE (t) == FUNCTION_DECL) { current_function_decl = TREE_VALUE (saved_access_scope); saved_access_scope = TREE_CHAIN (saved_access_scope); } if (DECL_FRIEND_CONTEXT (t) || DECL_CLASS_SCOPE_P (t)) pop_nested_class (); else pop_from_top_level (); } /* Do any processing required when DECL (a member template declaration) is finished. Returns the TEMPLATE_DECL corresponding to DECL, unless it is a specialization, in which case the DECL itself is returned. */ tree finish_member_template_decl (tree decl) { if (decl == error_mark_node) return error_mark_node; gcc_assert (DECL_P (decl)); if (TREE_CODE (decl) == TYPE_DECL) { tree type; type = TREE_TYPE (decl); if (type == error_mark_node) return error_mark_node; if (MAYBE_CLASS_TYPE_P (type) && CLASSTYPE_TEMPLATE_INFO (type) && !CLASSTYPE_TEMPLATE_SPECIALIZATION (type)) { tree tmpl = CLASSTYPE_TI_TEMPLATE (type); check_member_template (tmpl); return tmpl; } return NULL_TREE; } else if (TREE_CODE (decl) == FIELD_DECL) error ("data member %qD cannot be a member template", decl); else if (DECL_TEMPLATE_INFO (decl)) { if (!DECL_TEMPLATE_SPECIALIZATION (decl)) { check_member_template (DECL_TI_TEMPLATE (decl)); return DECL_TI_TEMPLATE (decl); } else return decl; } else error ("invalid member template declaration %qD", decl); return error_mark_node; } /* Create a template info node. */ tree build_template_info (tree template_decl, tree template_args) { tree result = make_node (TEMPLATE_INFO); TI_TEMPLATE (result) = template_decl; TI_ARGS (result) = template_args; return result; } /* Return the template info node corresponding to T, whatever T is. */ tree get_template_info (const_tree t) { tree tinfo = NULL_TREE; if (!t || t == error_mark_node) return NULL; if (DECL_P (t) && DECL_LANG_SPECIFIC (t)) tinfo = DECL_TEMPLATE_INFO (t); if (!tinfo && DECL_IMPLICIT_TYPEDEF_P (t)) t = TREE_TYPE (t); if (TAGGED_TYPE_P (t)) tinfo = TYPE_TEMPLATE_INFO (t); else if (TREE_CODE (t) == BOUND_TEMPLATE_TEMPLATE_PARM) tinfo = TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO (t); return tinfo; } /* Returns the template nesting level of the indicated class TYPE. For example, in: template <class T> struct A { template <class U> struct B {}; }; A<T>::B<U> has depth two, while A<T> has depth one. Both A<T>::B<int> and A<int>::B<U> have depth one, if they are instantiations, not specializations. This function is guaranteed to return 0 if passed NULL_TREE so that, for example, `template_class_depth (current_class_type)' is always safe. */ int template_class_depth (tree type) { int depth; for (depth = 0; type && TREE_CODE (type) != NAMESPACE_DECL; type = (TREE_CODE (type) == FUNCTION_DECL) ? CP_DECL_CONTEXT (type) : TYPE_CONTEXT (type)) { tree tinfo = get_template_info (type); if (tinfo && PRIMARY_TEMPLATE_P (TI_TEMPLATE (tinfo)) && uses_template_parms (INNERMOST_TEMPLATE_ARGS (TI_ARGS (tinfo)))) ++depth; } return depth; } /* Subroutine of maybe_begin_member_template_processing. Returns true if processing DECL needs us to push template parms. */ static bool inline_needs_template_parms (tree decl) { if (! DECL_TEMPLATE_INFO (decl)) return false; return (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (most_general_template (decl))) > (processing_template_decl + DECL_TEMPLATE_SPECIALIZATION (decl))); } /* Subroutine of maybe_begin_member_template_processing. Push the template parms in PARMS, starting from LEVELS steps into the chain, and ending at the beginning, since template parms are listed innermost first. */ static void push_inline_template_parms_recursive (tree parmlist, int levels) { tree parms = TREE_VALUE (parmlist); int i; if (levels > 1) push_inline_template_parms_recursive (TREE_CHAIN (parmlist), levels - 1); ++processing_template_decl; current_template_parms = tree_cons (size_int (processing_template_decl), parms, current_template_parms); TEMPLATE_PARMS_FOR_INLINE (current_template_parms) = 1; begin_scope (TREE_VEC_LENGTH (parms) ? sk_template_parms : sk_template_spec, NULL); for (i = 0; i < TREE_VEC_LENGTH (parms); ++i) { tree parm = TREE_VALUE (TREE_VEC_ELT (parms, i)); if (parm == error_mark_node) continue; gcc_assert (DECL_P (parm)); switch (TREE_CODE (parm)) { case TYPE_DECL: case TEMPLATE_DECL: pushdecl (parm); break; case PARM_DECL: { /* Make a CONST_DECL as is done in process_template_parm. It is ugly that we recreate this here; the original version built in process_template_parm is no longer available. */ tree decl = build_decl (DECL_SOURCE_LOCATION (parm), CONST_DECL, DECL_NAME (parm), TREE_TYPE (parm)); DECL_ARTIFICIAL (decl) = 1; TREE_CONSTANT (decl) = 1; TREE_READONLY (decl) = 1; DECL_INITIAL (decl) = DECL_INITIAL (parm); SET_DECL_TEMPLATE_PARM_P (decl); pushdecl (decl); } break; default: gcc_unreachable (); } } } /* Restore the template parameter context for a member template or a friend template defined in a class definition. */ void maybe_begin_member_template_processing (tree decl) { tree parms; int levels = 0; if (inline_needs_template_parms (decl)) { parms = DECL_TEMPLATE_PARMS (most_general_template (decl)); levels = TMPL_PARMS_DEPTH (parms) - processing_template_decl; if (DECL_TEMPLATE_SPECIALIZATION (decl)) { --levels; parms = TREE_CHAIN (parms); } push_inline_template_parms_recursive (parms, levels); } /* Remember how many levels of template parameters we pushed so that we can pop them later. */ VEC_safe_push (int, heap, inline_parm_levels, levels); } /* Undo the effects of maybe_begin_member_template_processing. */ void maybe_end_member_template_processing (void) { int i; int last; if (VEC_length (int, inline_parm_levels) == 0) return; last = VEC_pop (int, inline_parm_levels); for (i = 0; i < last; ++i) { --processing_template_decl; current_template_parms = TREE_CHAIN (current_template_parms); poplevel (0, 0, 0); } } /* Return a new template argument vector which contains all of ARGS, but has as its innermost set of arguments the EXTRA_ARGS. */ static tree add_to_template_args (tree args, tree extra_args) { tree new_args; int extra_depth; int i; int j; if (args == NULL_TREE) return extra_args; extra_depth = TMPL_ARGS_DEPTH (extra_args); new_args = make_tree_vec (TMPL_ARGS_DEPTH (args) + extra_depth); for (i = 1; i <= TMPL_ARGS_DEPTH (args); ++i) SET_TMPL_ARGS_LEVEL (new_args, i, TMPL_ARGS_LEVEL (args, i)); for (j = 1; j <= extra_depth; ++j, ++i) SET_TMPL_ARGS_LEVEL (new_args, i, TMPL_ARGS_LEVEL (extra_args, j)); return new_args; } /* Like add_to_template_args, but only the outermost ARGS are added to the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH (EXTRA_ARGS) levels are added. This function is used to combine the template arguments from a partial instantiation with the template arguments used to attain the full instantiation from the partial instantiation. */ static tree add_outermost_template_args (tree args, tree extra_args) { tree new_args; /* If there are more levels of EXTRA_ARGS than there are ARGS, something very fishy is going on. */ gcc_assert (TMPL_ARGS_DEPTH (args) >= TMPL_ARGS_DEPTH (extra_args)); /* If *all* the new arguments will be the EXTRA_ARGS, just return them. */ if (TMPL_ARGS_DEPTH (args) == TMPL_ARGS_DEPTH (extra_args)) return extra_args; /* For the moment, we make ARGS look like it contains fewer levels. */ TREE_VEC_LENGTH (args) -= TMPL_ARGS_DEPTH (extra_args); new_args = add_to_template_args (args, extra_args); /* Now, we restore ARGS to its full dimensions. */ TREE_VEC_LENGTH (args) += TMPL_ARGS_DEPTH (extra_args); return new_args; } /* Return the N levels of innermost template arguments from the ARGS. */ tree get_innermost_template_args (tree args, int n) { tree new_args; int extra_levels; int i; gcc_assert (n >= 0); /* If N is 1, just return the innermost set of template arguments. */ if (n == 1) return TMPL_ARGS_LEVEL (args, TMPL_ARGS_DEPTH (args)); /* If we're not removing anything, just return the arguments we were given. */ extra_levels = TMPL_ARGS_DEPTH (args) - n; gcc_assert (extra_levels >= 0); if (extra_levels == 0) return args; /* Make a new set of arguments, not containing the outer arguments. */ new_args = make_tree_vec (n); for (i = 1; i <= n; ++i) SET_TMPL_ARGS_LEVEL (new_args, i, TMPL_ARGS_LEVEL (args, i + extra_levels)); return new_args; } /* The inverse of get_innermost_template_args: Return all but the innermost EXTRA_LEVELS levels of template arguments from the ARGS. */ static tree strip_innermost_template_args (tree args, int extra_levels) { tree new_args; int n = TMPL_ARGS_DEPTH (args) - extra_levels; int i; gcc_assert (n >= 0); /* If N is 1, just return the outermost set of template arguments. */ if (n == 1) return TMPL_ARGS_LEVEL (args, 1); /* If we're not removing anything, just return the arguments we were given. */ gcc_assert (extra_levels >= 0); if (extra_levels == 0) return args; /* Make a new set of arguments, not containing the inner arguments. */ new_args = make_tree_vec (n); for (i = 1; i <= n; ++i) SET_TMPL_ARGS_LEVEL (new_args, i, TMPL_ARGS_LEVEL (args, i)); return new_args; } /* We've got a template header coming up; push to a new level for storing the parms. */ void begin_template_parm_list (void) { /* We use a non-tag-transparent scope here, which causes pushtag to put tags in this scope, rather than in the enclosing class or namespace scope. This is the right thing, since we want TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a global template class, push_template_decl handles putting the TEMPLATE_DECL into top-level scope. For a nested template class, e.g.: template <class T> struct S1 { template <class T> struct S2 {}; }; pushtag contains special code to call pushdecl_with_scope on the TEMPLATE_DECL for S2. */ begin_scope (sk_template_parms, NULL); ++processing_template_decl; ++processing_template_parmlist; note_template_header (0); } /* This routine is called when a specialization is declared. If it is invalid to declare a specialization here, an error is reported and false is returned, otherwise this routine will return true. */ static bool check_specialization_scope (void) { tree scope = current_scope (); /* [temp.expl.spec] An explicit specialization shall be declared in the namespace of which the template is a member, or, for member templates, in the namespace of which the enclosing class or enclosing class template is a member. An explicit specialization of a member function, member class or static data member of a class template shall be declared in the namespace of which the class template is a member. */ if (scope && TREE_CODE (scope) != NAMESPACE_DECL) { error ("explicit specialization in non-namespace scope %qD", scope); return false; } /* [temp.expl.spec] In an explicit specialization declaration for a member of a class template or a member template that appears in namespace scope, the member template and some of its enclosing class templates may remain unspecialized, except that the declaration shall not explicitly specialize a class member template if its enclosing class templates are not explicitly specialized as well. */ if (current_template_parms) { error ("enclosing class templates are not explicitly specialized"); return false; } return true; } /* We've just seen template <>. */ bool begin_specialization (void) { begin_scope (sk_template_spec, NULL); note_template_header (1); return check_specialization_scope (); } /* Called at then end of processing a declaration preceded by template<>. */ void end_specialization (void) { finish_scope (); reset_specialization (); } /* Any template <>'s that we have seen thus far are not referring to a function specialization. */ void reset_specialization (void) { processing_specialization = 0; template_header_count = 0; } /* We've just seen a template header. If SPECIALIZATION is nonzero, it was of the form template <>. */ static void note_template_header (int specialization) { processing_specialization = specialization; template_header_count++; } /* We're beginning an explicit instantiation. */ void begin_explicit_instantiation (void) { gcc_assert (!processing_explicit_instantiation); processing_explicit_instantiation = true; } void end_explicit_instantiation (void) { gcc_assert (processing_explicit_instantiation); processing_explicit_instantiation = false; } /* An explicit specialization or partial specialization TMPL is being declared. Check that the namespace in which the specialization is occurring is permissible. Returns false iff it is invalid to specialize TMPL in the current namespace. */ static bool check_specialization_namespace (tree tmpl) { tree tpl_ns = decl_namespace_context (tmpl); /* [tmpl.expl.spec] An explicit specialization shall be declared in the namespace of which the template is a member, or, for member templates, in the namespace of which the enclosing class or enclosing class template is a member. An explicit specialization of a member function, member class or static data member of a class template shall be declared in the namespace of which the class template is a member. */ if (current_scope() != DECL_CONTEXT (tmpl) && !at_namespace_scope_p ()) { error ("specialization of %qD must appear at namespace scope", tmpl); return false; } if (is_associated_namespace (current_namespace, tpl_ns)) /* Same or super-using namespace. */ return true; else { permerror (input_location, "specialization of %qD in different namespace", tmpl); permerror (input_location, " from definition of %q+#D", tmpl); return false; } } /* SPEC is an explicit instantiation. Check that it is valid to perform this explicit instantiation in the current namespace. */ static void check_explicit_instantiation_namespace (tree spec) { tree ns; /* DR 275: An explicit instantiation shall appear in an enclosing namespace of its template. */ ns = decl_namespace_context (spec); if (!is_ancestor (current_namespace, ns)) permerror (input_location, "explicit instantiation of %qD in namespace %qD " "(which does not enclose namespace %qD)", spec, current_namespace, ns); } /* The TYPE is being declared. If it is a template type, that means it is a partial specialization. Do appropriate error-checking. */ tree maybe_process_partial_specialization (tree type) { tree context; if (type == error_mark_node) return error_mark_node; if (TREE_CODE (type) == BOUND_TEMPLATE_TEMPLATE_PARM) { error ("name of class shadows template template parameter %qD", TYPE_NAME (type)); return error_mark_node; } context = TYPE_CONTEXT (type); if (CLASS_TYPE_P (type) && CLASSTYPE_USE_TEMPLATE (type)) { /* This is for ordinary explicit specialization and partial specialization of a template class such as: template <> class C<int>; or: template <class T> class C<T*>; Make sure that `C<int>' and `C<T*>' are implicit instantiations. */ if (CLASSTYPE_IMPLICIT_INSTANTIATION (type) && !COMPLETE_TYPE_P (type)) { check_specialization_namespace (CLASSTYPE_TI_TEMPLATE (type)); SET_CLASSTYPE_TEMPLATE_SPECIALIZATION (type); if (processing_template_decl) { if (push_template_decl (TYPE_MAIN_DECL (type)) == error_mark_node) return error_mark_node; } } else if (CLASSTYPE_TEMPLATE_INSTANTIATION (type)) error ("specialization of %qT after instantiation", type); } else if (CLASS_TYPE_P (type) && !CLASSTYPE_USE_TEMPLATE (type) && CLASSTYPE_TEMPLATE_INFO (type) && context && CLASS_TYPE_P (context) && CLASSTYPE_TEMPLATE_INFO (context)) { /* This is for an explicit specialization of member class template according to [temp.expl.spec/18]: template <> template <class U> class C<int>::D; The context `C<int>' must be an implicit instantiation. Otherwise this is just a member class template declared earlier like: template <> class C<int> { template <class U> class D; }; template <> template <class U> class C<int>::D; In the first case, `C<int>::D' is a specialization of `C<T>::D' while in the second case, `C<int>::D' is a primary template and `C<T>::D' may not exist. */ if (CLASSTYPE_IMPLICIT_INSTANTIATION (context) && !COMPLETE_TYPE_P (type)) { tree t; tree tmpl = CLASSTYPE_TI_TEMPLATE (type); if (current_namespace != decl_namespace_context (tmpl)) { permerror (input_location, "specializing %q#T in different namespace", type); permerror (input_location, " from definition of %q+#D", tmpl); } /* Check for invalid specialization after instantiation: template <> template <> class C<int>::D<int>; template <> template <class U> class C<int>::D; */ for (t = DECL_TEMPLATE_INSTANTIATIONS (tmpl); t; t = TREE_CHAIN (t)) { tree inst = TREE_VALUE (t); if (CLASSTYPE_TEMPLATE_SPECIALIZATION (inst)) { /* We already have a full specialization of this partial instantiation. Reassign it to the new member specialization template. */ spec_entry elt; spec_entry **slot; elt.tmpl = most_general_template (tmpl); elt.args = CLASSTYPE_TI_ARGS (inst); elt.spec = inst; htab_remove_elt (type_specializations, &elt); elt.tmpl = tmpl; elt.args = INNERMOST_TEMPLATE_ARGS (elt.args); slot = (spec_entry **) htab_find_slot (type_specializations, &elt, INSERT); *slot = GGC_NEW (spec_entry); **slot = elt; } else if (COMPLETE_TYPE_P (inst) || TYPE_BEING_DEFINED (inst)) /* But if we've had an implicit instantiation, that's a problem ([temp.expl.spec]/6). */ error ("specialization %qT after instantiation %qT", type, inst); } /* Mark TYPE as a specialization. And as a result, we only have one level of template argument for the innermost class template. */ SET_CLASSTYPE_TEMPLATE_SPECIALIZATION (type); CLASSTYPE_TI_ARGS (type) = INNERMOST_TEMPLATE_ARGS (CLASSTYPE_TI_ARGS (type)); } } else if (processing_specialization) { error ("explicit specialization of non-template %qT", type); return error_mark_node; } return type; } /* Returns nonzero if we can optimize the retrieval of specializations for TMPL, a TEMPLATE_DECL. In particular, for such a template, we do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */ static inline bool optimize_specialization_lookup_p (tree tmpl) { return (DECL_FUNCTION_TEMPLATE_P (tmpl) && DECL_CLASS_SCOPE_P (tmpl) /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template parameter. */ && CLASS_TYPE_P (DECL_CONTEXT (tmpl)) /* The optimized lookup depends on the fact that the template arguments for the member function template apply purely to the containing class, which is not true if the containing class is an explicit or partial specialization. */ && !CLASSTYPE_TEMPLATE_SPECIALIZATION (DECL_CONTEXT (tmpl)) && !DECL_MEMBER_TEMPLATE_P (tmpl) && !DECL_CONV_FN_P (tmpl) /* It is possible to have a template that is not a member template and is not a member of a template class: template <typename T> struct S { friend A::f(); }; Here, the friend function is a template, but the context does not have template information. The optimized lookup relies on having ARGS be the template arguments for both the class and the function template. */ && !DECL_FRIEND_P (DECL_TEMPLATE_RESULT (tmpl))); } /* Retrieve the specialization (in the sense of [temp.spec] - a specialization is either an instantiation or an explicit specialization) of TMPL for the given template ARGS. If there is no such specialization, return NULL_TREE. The ARGS are a vector of arguments, or a vector of vectors of arguments, in the case of templates with more than one level of parameters. If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true, then we search for a partial specialization matching ARGS. This parameter is ignored if TMPL is not a class template. */ static tree retrieve_specialization (tree tmpl, tree args, hashval_t hash) { if (args == error_mark_node) return NULL_TREE; gcc_assert (TREE_CODE (tmpl) == TEMPLATE_DECL); /* There should be as many levels of arguments as there are levels of parameters. */ gcc_assert (TMPL_ARGS_DEPTH (args) == TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (tmpl))); if (optimize_specialization_lookup_p (tmpl)) { tree class_template; tree class_specialization; VEC(tree,gc) *methods; tree fns; int idx; /* The template arguments actually apply to the containing class. Find the class specialization with those arguments. */ class_template = CLASSTYPE_TI_TEMPLATE (DECL_CONTEXT (tmpl)); class_specialization = retrieve_specialization (class_template, args, 0); if (!class_specialization) return NULL_TREE; /* Now, find the appropriate entry in the CLASSTYPE_METHOD_VEC for the specialization. */ idx = class_method_index_for_fn (class_specialization, tmpl); if (idx == -1) return NULL_TREE; /* Iterate through the methods with the indicated name, looking for the one that has an instance of TMPL. */ methods = CLASSTYPE_METHOD_VEC (class_specialization); for (fns = VEC_index (tree, methods, idx); fns; fns = OVL_NEXT (fns)) { tree fn = OVL_CURRENT (fns); if (DECL_TEMPLATE_INFO (fn) && DECL_TI_TEMPLATE (fn) == tmpl /* using-declarations can add base methods to the method vec, and we don't want those here. */ && DECL_CONTEXT (fn) == class_specialization) return fn; } return NULL_TREE; } else { spec_entry *found; spec_entry elt; htab_t specializations; elt.tmpl = tmpl; elt.args = args; elt.spec = NULL_TREE; if (DECL_CLASS_TEMPLATE_P (tmpl)) specializations = type_specializations; else specializations = decl_specializations; if (hash == 0) hash = hash_specialization (&elt); found = (spec_entry *) htab_find_with_hash (specializations, &elt, hash); if (found) return found->spec; } return NULL_TREE; } /* Like retrieve_specialization, but for local declarations. */ static tree retrieve_local_specialization (tree tmpl) { tree spec; if (local_specializations == NULL) return NULL_TREE; spec = (tree) htab_find_with_hash (local_specializations, tmpl, htab_hash_pointer (tmpl)); return spec ? TREE_PURPOSE (spec) : NULL_TREE; } /* Returns nonzero iff DECL is a specialization of TMPL. */ int is_specialization_of (tree decl, tree tmpl) { tree t; if (TREE_CODE (decl) == FUNCTION_DECL) { for (t = decl; t != NULL_TREE; t = DECL_TEMPLATE_INFO (t) ? DECL_TI_TEMPLATE (t) : NULL_TREE) if (t == tmpl) return 1; } else { gcc_assert (TREE_CODE (decl) == TYPE_DECL); for (t = TREE_TYPE (decl); t != NULL_TREE; t = CLASSTYPE_USE_TEMPLATE (t) ? TREE_TYPE (CLASSTYPE_TI_TEMPLATE (t)) : NULL_TREE) if (same_type_ignoring_top_level_qualifiers_p (t, TREE_TYPE (tmpl))) return 1; } return 0; } /* Returns nonzero iff DECL is a specialization of friend declaration FRIEND_DECL according to [temp.friend]. */ bool is_specialization_of_friend (tree decl, tree friend_decl) { bool need_template = true; int template_depth; gcc_assert (TREE_CODE (decl) == FUNCTION_DECL || TREE_CODE (decl) == TYPE_DECL); /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function of a template class, we want to check if DECL is a specialization if this. */ if (TREE_CODE (friend_decl) == FUNCTION_DECL && DECL_TEMPLATE_INFO (friend_decl) && !DECL_USE_TEMPLATE (friend_decl)) { /* We want a TEMPLATE_DECL for `is_specialization_of'. */ friend_decl = DECL_TI_TEMPLATE (friend_decl); need_template = false; } else if (TREE_CODE (friend_decl) == TEMPLATE_DECL && !PRIMARY_TEMPLATE_P (friend_decl)) need_template = false; /* There is nothing to do if this is not a template friend. */ if (TREE_CODE (friend_decl) != TEMPLATE_DECL) return false; if (is_specialization_of (decl, friend_decl)) return true; /* [temp.friend/6] A member of a class template may be declared to be a friend of a non-template class. In this case, the corresponding member of every specialization of the class template is a friend of the class granting friendship. For example, given a template friend declaration template <class T> friend void A<T>::f(); the member function below is considered a friend template <> struct A<int> { void f(); }; For this type of template friend, TEMPLATE_DEPTH below will be nonzero. To determine if DECL is a friend of FRIEND, we first check if the enclosing class is a specialization of another. */ template_depth = template_class_depth (DECL_CONTEXT (friend_decl)); if (template_depth && DECL_CLASS_SCOPE_P (decl) && is_specialization_of (TYPE_NAME (DECL_CONTEXT (decl)), CLASSTYPE_TI_TEMPLATE (DECL_CONTEXT (friend_decl)))) { /* Next, we check the members themselves. In order to handle a few tricky cases, such as when FRIEND_DECL's are template <class T> friend void A<T>::g(T t); template <class T> template <T t> friend void A<T>::h(); and DECL's are void A<int>::g(int); template <int> void A<int>::h(); we need to figure out ARGS, the template arguments from the context of DECL. This is required for template substitution of `T' in the function parameter of `g' and template parameter of `h' in the above examples. Here ARGS corresponds to `int'. */ tree context = DECL_CONTEXT (decl); tree args = NULL_TREE; int current_depth = 0; while (current_depth < template_depth) { if (CLASSTYPE_TEMPLATE_INFO (context)) { if (current_depth == 0) args = TYPE_TI_ARGS (context); else args = add_to_template_args (TYPE_TI_ARGS (context), args); current_depth++; } context = TYPE_CONTEXT (context); } if (TREE_CODE (decl) == FUNCTION_DECL) { bool is_template; tree friend_type; tree decl_type; tree friend_args_type; tree decl_args_type; /* Make sure that both DECL and FRIEND_DECL are templates or non-templates. */ is_template = DECL_TEMPLATE_INFO (decl) && PRIMARY_TEMPLATE_P (DECL_TI_TEMPLATE (decl)); if (need_template ^ is_template) return false; else if (is_template) { /* If both are templates, check template parameter list. */ tree friend_parms = tsubst_template_parms (DECL_TEMPLATE_PARMS (friend_decl), args, tf_none); if (!comp_template_parms (DECL_TEMPLATE_PARMS (DECL_TI_TEMPLATE (decl)), friend_parms)) return false; decl_type = TREE_TYPE (DECL_TI_TEMPLATE (decl)); } else decl_type = TREE_TYPE (decl); friend_type = tsubst_function_type (TREE_TYPE (friend_decl), args, tf_none, NULL_TREE); if (friend_type == error_mark_node) return false; /* Check if return types match. */ if (!same_type_p (TREE_TYPE (decl_type), TREE_TYPE (friend_type))) return false; /* Check if function parameter types match, ignoring the `this' parameter. */ friend_args_type = TYPE_ARG_TYPES (friend_type); decl_args_type = TYPE_ARG_TYPES (decl_type); if (DECL_NONSTATIC_MEMBER_FUNCTION_P (friend_decl)) friend_args_type = TREE_CHAIN (friend_args_type); if (DECL_NONSTATIC_MEMBER_FUNCTION_P (decl)) decl_args_type = TREE_CHAIN (decl_args_type); return compparms (decl_args_type, friend_args_type); } else { /* DECL is a TYPE_DECL */ bool is_template; tree decl_type = TREE_TYPE (decl); /* Make sure that both DECL and FRIEND_DECL are templates or non-templates. */ is_template = CLASSTYPE_TEMPLATE_INFO (decl_type) && PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (decl_type)); if (need_template ^ is_template) return false; else if (is_template) { tree friend_parms; /* If both are templates, check the name of the two TEMPLATE_DECL's first because is_friend didn't. */ if (DECL_NAME (CLASSTYPE_TI_TEMPLATE (decl_type)) != DECL_NAME (friend_decl)) return false; /* Now check template parameter list. */ friend_parms = tsubst_template_parms (DECL_TEMPLATE_PARMS (friend_decl), args, tf_none); return comp_template_parms (DECL_TEMPLATE_PARMS (CLASSTYPE_TI_TEMPLATE (decl_type)), friend_parms); } else return (DECL_NAME (decl) == DECL_NAME (friend_decl)); } } return false; } /* Register the specialization SPEC as a specialization of TMPL with the indicated ARGS. IS_FRIEND indicates whether the specialization is actually just a friend declaration. Returns SPEC, or an equivalent prior declaration, if available. */ static tree register_specialization (tree spec, tree tmpl, tree args, bool is_friend, hashval_t hash) { tree fn; spec_entry **slot = NULL; spec_entry elt; gcc_assert (TREE_CODE (tmpl) == TEMPLATE_DECL && DECL_P (spec)); if (TREE_CODE (spec) == FUNCTION_DECL && uses_template_parms (DECL_TI_ARGS (spec))) /* This is the FUNCTION_DECL for a partial instantiation. Don't register it; we want the corresponding TEMPLATE_DECL instead. We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than the more obvious `uses_template_parms (spec)' to avoid problems with default function arguments. In particular, given something like this: template <class T> void f(T t1, T t = T()) the default argument expression is not substituted for in an instantiation unless and until it is actually needed. */ return spec; if (optimize_specialization_lookup_p (tmpl)) /* We don't put these specializations in the hash table, but we might want to give an error about a mismatch. */ fn = retrieve_specialization (tmpl, args, 0); else { elt.tmpl = tmpl; elt.args = args; elt.spec = spec; if (hash == 0) hash = hash_specialization (&elt); slot = (spec_entry **) htab_find_slot_with_hash (decl_specializations, &elt, hash, INSERT); if (*slot) fn = (*slot)->spec; else fn = NULL_TREE; } /* We can sometimes try to re-register a specialization that we've already got. In particular, regenerate_decl_from_template calls duplicate_decls which will update the specialization list. But, we'll still get called again here anyhow. It's more convenient to simply allow this than to try to prevent it. */ if (fn == spec) return spec; else if (fn && DECL_TEMPLATE_SPECIALIZATION (spec)) { if (DECL_TEMPLATE_INSTANTIATION (fn)) { if (DECL_ODR_USED (fn) || DECL_EXPLICIT_INSTANTIATION (fn)) { error ("specialization of %qD after instantiation", fn); return error_mark_node; } else { tree clone; /* This situation should occur only if the first specialization is an implicit instantiation, the second is an explicit specialization, and the implicit instantiation has not yet been used. That situation can occur if we have implicitly instantiated a member function and then specialized it later. We can also wind up here if a friend declaration that looked like an instantiation turns out to be a specialization: template <class T> void foo(T); class S { friend void foo<>(int) }; template <> void foo(int); We transform the existing DECL in place so that any pointers to it become pointers to the updated declaration. If there was a definition for the template, but not for the specialization, we want this to look as if there were no definition, and vice versa. */ DECL_INITIAL (fn) = NULL_TREE; duplicate_decls (spec, fn, is_friend); /* The call to duplicate_decls will have applied [temp.expl.spec]: An explicit specialization of a function template is inline only if it is explicitly declared to be, and independently of whether its function template is. to the primary function; now copy the inline bits to the various clones. */ FOR_EACH_CLONE (clone, fn) { DECL_DECLARED_INLINE_P (clone) = DECL_DECLARED_INLINE_P (fn); DECL_SOURCE_LOCATION (clone) = DECL_SOURCE_LOCATION (fn); } check_specialization_namespace (fn); return fn; } } else if (DECL_TEMPLATE_SPECIALIZATION (fn)) { if (!duplicate_decls (spec, fn, is_friend) && DECL_INITIAL (spec)) /* Dup decl failed, but this is a new definition. Set the line number so any errors match this new definition. */ DECL_SOURCE_LOCATION (fn) = DECL_SOURCE_LOCATION (spec); return fn; } } else if (fn) return duplicate_decls (spec, fn, is_friend); /* A specialization must be declared in the same namespace as the template it is specializing. */ if (DECL_TEMPLATE_SPECIALIZATION (spec) && !check_specialization_namespace (tmpl)) DECL_CONTEXT (spec) = DECL_CONTEXT (tmpl); if (!optimize_specialization_lookup_p (tmpl)) { gcc_assert (tmpl && args && spec); *slot = GGC_NEW (spec_entry); **slot = elt; if (TREE_CODE (spec) == FUNCTION_DECL && DECL_NAMESPACE_SCOPE_P (spec) && PRIMARY_TEMPLATE_P (tmpl) && DECL_SAVED_TREE (DECL_TEMPLATE_RESULT (tmpl)) == NULL_TREE) /* TMPL is a forward declaration of a template function; keep a list of all specializations in case we need to reassign them to a friend template later in tsubst_friend_function. */ DECL_TEMPLATE_INSTANTIATIONS (tmpl) = tree_cons (args, spec, DECL_TEMPLATE_INSTANTIATIONS (tmpl)); } return spec; } /* Returns true iff two spec_entry nodes are equivalent. Only compares the TMPL and ARGS members, ignores SPEC. */ static int eq_specializations (const void *p1, const void *p2) { const spec_entry *e1 = (const spec_entry *)p1; const spec_entry *e2 = (const spec_entry *)p2; return (e1->tmpl == e2->tmpl && comp_template_args (e1->args, e2->args)); } /* Returns a hash for a template TMPL and template arguments ARGS. */ static hashval_t hash_tmpl_and_args (tree tmpl, tree args) { hashval_t val = DECL_UID (tmpl); return iterative_hash_template_arg (args, val); } /* Returns a hash for a spec_entry node based on the TMPL and ARGS members, ignoring SPEC. */ static hashval_t hash_specialization (const void *p) { const spec_entry *e = (const spec_entry *)p; return hash_tmpl_and_args (e->tmpl, e->args); } /* Recursively calculate a hash value for a template argument ARG, for use in the hash tables of template specializations. */ static hashval_t iterative_hash_template_arg (tree arg, hashval_t val) { unsigned HOST_WIDE_INT i; enum tree_code code; char tclass; if (arg == NULL_TREE) return iterative_hash_object (arg, val); if (!TYPE_P (arg)) STRIP_NOPS (arg); if (TREE_CODE (arg) == ARGUMENT_PACK_SELECT) /* We can get one of these when re-hashing a previous entry in the middle of substituting into a pack expansion. Just look through it. */ arg = ARGUMENT_PACK_SELECT_FROM_PACK (arg); code = TREE_CODE (arg); tclass = TREE_CODE_CLASS (code); val = iterative_hash_object (code, val); switch (code) { case ERROR_MARK: return val; case IDENTIFIER_NODE: return iterative_hash_object (IDENTIFIER_HASH_VALUE (arg), val); case TREE_VEC: { int i, len = TREE_VEC_LENGTH (arg); for (i = 0; i < len; ++i) val = iterative_hash_template_arg (TREE_VEC_ELT (arg, i), val); return val; } case TYPE_PACK_EXPANSION: case EXPR_PACK_EXPANSION: return iterative_hash_template_arg (PACK_EXPANSION_PATTERN (arg), val); case TYPE_ARGUMENT_PACK: case NONTYPE_ARGUMENT_PACK: return iterative_hash_template_arg (ARGUMENT_PACK_ARGS (arg), val); case TREE_LIST: for (; arg; arg = TREE_CHAIN (arg)) val = iterative_hash_template_arg (TREE_VALUE (arg), val); return val; case OVERLOAD: for (; arg; arg = OVL_CHAIN (arg)) val = iterative_hash_template_arg (OVL_FUNCTION (arg), val); return val; case CONSTRUCTOR: { tree field, value; FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (arg), i, field, value) { val = iterative_hash_template_arg (field, val); val = iterative_hash_template_arg (value, val); } return val; } case PARM_DECL: if (!DECL_ARTIFICIAL (arg)) val = iterative_hash_object (DECL_PARM_INDEX (arg), val); return iterative_hash_template_arg (TREE_TYPE (arg), val); case TARGET_EXPR: return iterative_hash_template_arg (TARGET_EXPR_INITIAL (arg), val); case PTRMEM_CST: val = iterative_hash_template_arg (PTRMEM_CST_CLASS (arg), val); return iterative_hash_template_arg (PTRMEM_CST_MEMBER (arg), val); case TEMPLATE_PARM_INDEX: val = iterative_hash_template_arg (TREE_TYPE (TEMPLATE_PARM_DECL (arg)), val); val = iterative_hash_object (TEMPLATE_PARM_LEVEL (arg), val); return iterative_hash_object (TEMPLATE_PARM_IDX (arg), val); case TRAIT_EXPR: val = iterative_hash_object (TRAIT_EXPR_KIND (arg), val); val = iterative_hash_template_arg (TRAIT_EXPR_TYPE1 (arg), val); return iterative_hash_template_arg (TRAIT_EXPR_TYPE2 (arg), val); case BASELINK: val = iterative_hash_template_arg (BINFO_TYPE (BASELINK_BINFO (arg)), val); return iterative_hash_template_arg (DECL_NAME (get_first_fn (arg)), val); case MODOP_EXPR: val = iterative_hash_template_arg (TREE_OPERAND (arg, 0), val); code = TREE_CODE (TREE_OPERAND (arg, 1)); val = iterative_hash_object (code, val); return iterative_hash_template_arg (TREE_OPERAND (arg, 2), val); case ARRAY_TYPE: /* layout_type sets structural equality for arrays of incomplete type, so we can't rely on the canonical type for hashing. */ val = iterative_hash_template_arg (TREE_TYPE (arg), val); return iterative_hash_template_arg (TYPE_DOMAIN (arg), val); case LAMBDA_EXPR: /* A lambda can't appear in a template arg, but don't crash on erroneous input. */ gcc_assert (errorcount > 0); return val; default: switch (tclass) { case tcc_type: if (TYPE_CANONICAL (arg)) return iterative_hash_object (TYPE_HASH (TYPE_CANONICAL (arg)), val); else if (TREE_CODE (arg) == DECLTYPE_TYPE) return iterative_hash_template_arg (DECLTYPE_TYPE_EXPR (arg), val); /* Otherwise just compare the types during lookup. */ return val; case tcc_declaration: case tcc_constant: return iterative_hash_expr (arg, val); default: gcc_assert (IS_EXPR_CODE_CLASS (tclass)); { unsigned n = TREE_OPERAND_LENGTH (arg); for (i = 0; i < n; ++i) val = iterative_hash_template_arg (TREE_OPERAND (arg, i), val); return val; } } } gcc_unreachable (); return 0; } /* Unregister the specialization SPEC as a specialization of TMPL. Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true if the SPEC was listed as a specialization of TMPL. Note that SPEC has been ggc_freed, so we can't look inside it. */ bool reregister_specialization (tree spec, tree tinfo, tree new_spec) { spec_entry **slot; spec_entry elt; elt.tmpl = most_general_template (TI_TEMPLATE (tinfo)); elt.args = TI_ARGS (tinfo); elt.spec = NULL_TREE; slot = (spec_entry **) htab_find_slot (decl_specializations, &elt, INSERT); if (*slot) { gcc_assert ((*slot)->spec == spec || (*slot)->spec == new_spec); gcc_assert (new_spec != NULL_TREE); (*slot)->spec = new_spec; return 1; } return 0; } /* Compare an entry in the local specializations hash table P1 (which is really a pointer to a TREE_LIST) with P2 (which is really a DECL). */ static int eq_local_specializations (const void *p1, const void *p2) { return TREE_VALUE ((const_tree) p1) == (const_tree) p2; } /* Hash P1, an entry in the local specializations table. */ static hashval_t hash_local_specialization (const void* p1) { return htab_hash_pointer (TREE_VALUE ((const_tree) p1)); } /* Like register_specialization, but for local declarations. We are registering SPEC, an instantiation of TMPL. */ static void register_local_specialization (tree spec, tree tmpl) { void **slot; slot = htab_find_slot_with_hash (local_specializations, tmpl, htab_hash_pointer (tmpl), INSERT); *slot = build_tree_list (spec, tmpl); } /* TYPE is a class type. Returns true if TYPE is an explicitly specialized class. */ bool explicit_class_specialization_p (tree type) { if (!CLASSTYPE_TEMPLATE_SPECIALIZATION (type)) return false; return !uses_template_parms (CLASSTYPE_TI_ARGS (type)); } /* Print the list of functions at FNS, going through all the overloads for each element of the list. Alternatively, FNS can not be a TREE_LIST, in which case it will be printed together with all the overloads. MORE and *STR should respectively be FALSE and NULL when the function is called from the outside. They are used internally on recursive calls. print_candidates manages the two parameters and leaves NULL in *STR when it ends. */ static void print_candidates_1 (tree fns, bool more, const char **str) { tree fn, fn2; char *spaces = NULL; for (fn = fns; fn; fn = OVL_NEXT (fn)) if (TREE_CODE (fn) == TREE_LIST) { gcc_assert (!OVL_NEXT (fn) && !is_overloaded_fn (fn)); for (fn2 = fn; fn2 != NULL_TREE; fn2 = TREE_CHAIN (fn2)) print_candidates_1 (TREE_VALUE (fn2), TREE_CHAIN (fn2) || more, str); } else { if (!*str) { /* Pick the prefix string. */ if (!more && !OVL_NEXT (fns)) { error ("candidate is: %+#D", OVL_CURRENT (fn)); continue; } *str = _("candidates are:"); spaces = get_spaces (*str); } error ("%s %+#D", *str, OVL_CURRENT (fn)); *str = spaces ? spaces : *str; } if (!more) { free (spaces); *str = NULL; } } /* Print the list of candidate FNS in an error message. */ void print_candidates (tree fns) { const char *str = NULL; print_candidates_1 (fns, false, &str); gcc_assert (str == NULL); } /* Returns the template (one of the functions given by TEMPLATE_ID) which can be specialized to match the indicated DECL with the explicit template args given in TEMPLATE_ID. The DECL may be NULL_TREE if none is available. In that case, the functions in TEMPLATE_ID are non-members. If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a specialization of a member template. The TEMPLATE_COUNT is the number of references to qualifying template classes that appeared in the name of the function. See check_explicit_specialization for a more accurate description. TSK indicates what kind of template declaration (if any) is being declared. TSK_TEMPLATE indicates that the declaration given by DECL, though a FUNCTION_DECL, has template parameters, and is therefore a template function. The template args (those explicitly specified and those deduced) are output in a newly created vector *TARGS_OUT. If it is impossible to determine the result, an error message is issued. The error_mark_node is returned to indicate failure. */ static tree determine_specialization (tree template_id, tree decl, tree* targs_out, int need_member_template, int template_count, tmpl_spec_kind tsk) { tree fns; tree targs; tree explicit_targs; tree candidates = NULL_TREE; /* A TREE_LIST of templates of which DECL may be a specialization. The TREE_VALUE of each node is a TEMPLATE_DECL. The corresponding TREE_PURPOSE is the set of template arguments that, when used to instantiate the template, would produce a function with the signature of DECL. */ tree templates = NULL_TREE; int header_count; struct cp_binding_level *b; *targs_out = NULL_TREE; if (template_id == error_mark_node || decl == error_mark_node) return error_mark_node; fns = TREE_OPERAND (template_id, 0); explicit_targs = TREE_OPERAND (template_id, 1); if (fns == error_mark_node) return error_mark_node; /* Check for baselinks. */ if (BASELINK_P (fns)) fns = BASELINK_FUNCTIONS (fns); if (!is_overloaded_fn (fns)) { error ("%qD is not a function template", fns); return error_mark_node; } /* Count the number of template headers specified for this specialization. */ header_count = 0; for (b = current_binding_level; b->kind == sk_template_parms; b = b->level_chain) ++header_count; for (; fns; fns = OVL_NEXT (fns)) { tree fn = OVL_CURRENT (fns); if (TREE_CODE (fn) == TEMPLATE_DECL) { tree decl_arg_types; tree fn_arg_types; /* In case of explicit specialization, we need to check if the number of template headers appearing in the specialization is correct. This is usually done in check_explicit_specialization, but the check done there cannot be exhaustive when specializing member functions. Consider the following code: template <> void A<int>::f(int); template <> template <> void A<int>::f(int); Assuming that A<int> is not itself an explicit specialization already, the first line specializes "f" which is a non-template member function, whilst the second line specializes "f" which is a template member function. So both lines are syntactically correct, and check_explicit_specialization does not reject them. Here, we can do better, as we are matching the specialization against the declarations. We count the number of template headers, and we check if they match TEMPLATE_COUNT + 1 (TEMPLATE_COUNT is the number of qualifying template classes, plus there must be another header for the member template itself). Notice that if header_count is zero, this is not a specialization but rather a template instantiation, so there is no check we can perform here. */ if (header_count && header_count != template_count + 1) continue; /* Check that the number of template arguments at the innermost level for DECL is the same as for FN. */ if (current_binding_level->kind == sk_template_parms && !current_binding_level->explicit_spec_p && (TREE_VEC_LENGTH (DECL_INNERMOST_TEMPLATE_PARMS (fn)) != TREE_VEC_LENGTH (INNERMOST_TEMPLATE_PARMS (current_template_parms)))) continue; /* DECL might be a specialization of FN. */ decl_arg_types = TYPE_ARG_TYPES (TREE_TYPE (decl)); fn_arg_types = TYPE_ARG_TYPES (TREE_TYPE (fn)); /* For a non-static member function, we need to make sure that the const qualification is the same. Since get_bindings does not try to merge the "this" parameter, we must do the comparison explicitly. */ if (DECL_NONSTATIC_MEMBER_FUNCTION_P (fn) && !same_type_p (TREE_VALUE (fn_arg_types), TREE_VALUE (decl_arg_types))) continue; /* Skip the "this" parameter and, for constructors of classes with virtual bases, the VTT parameter. A full specialization of a constructor will have a VTT parameter, but a template never will. */ decl_arg_types = skip_artificial_parms_for (decl, decl_arg_types); fn_arg_types = skip_artificial_parms_for (fn, fn_arg_types); /* Check that the number of function parameters matches. For example, template <class T> void f(int i = 0); template <> void f<int>(); The specialization f<int> is invalid but is not caught by get_bindings below. */ if (list_length (fn_arg_types) != list_length (decl_arg_types)) continue; /* Function templates cannot be specializations; there are no partial specializations of functions. Therefore, if the type of DECL does not match FN, there is no match. */ if (tsk == tsk_template) { if (compparms (fn_arg_types, decl_arg_types)) candidates = tree_cons (NULL_TREE, fn, candidates); continue; } /* See whether this function might be a specialization of this template. */ targs = get_bindings (fn, decl, explicit_targs, /*check_ret=*/true); if (!targs) /* We cannot deduce template arguments that when used to specialize TMPL will produce DECL. */ continue; /* Save this template, and the arguments deduced. */ templates = tree_cons (targs, fn, templates); } else if (need_member_template) /* FN is an ordinary member function, and we need a specialization of a member template. */ ; else if (TREE_CODE (fn) != FUNCTION_DECL) /* We can get IDENTIFIER_NODEs here in certain erroneous cases. */ ; else if (!DECL_FUNCTION_MEMBER_P (fn)) /* This is just an ordinary non-member function. Nothing can be a specialization of that. */ ; else if (DECL_ARTIFICIAL (fn)) /* Cannot specialize functions that are created implicitly. */ ; else { tree decl_arg_types; /* This is an ordinary member function. However, since we're here, we can assume it's enclosing class is a template class. For example, template <typename T> struct S { void f(); }; template <> void S<int>::f() {} Here, S<int>::f is a non-template, but S<int> is a template class. If FN has the same type as DECL, we might be in business. */ if (!DECL_TEMPLATE_INFO (fn)) /* Its enclosing class is an explicit specialization of a template class. This is not a candidate. */ continue; if (!same_type_p (TREE_TYPE (TREE_TYPE (decl)), TREE_TYPE (TREE_TYPE (fn)))) /* The return types differ. */ continue; /* Adjust the type of DECL in case FN is a static member. */ decl_arg_types = TYPE_ARG_TYPES (TREE_TYPE (decl)); if (DECL_STATIC_FUNCTION_P (fn) && DECL_NONSTATIC_MEMBER_FUNCTION_P (decl)) decl_arg_types = TREE_CHAIN (decl_arg_types); if (compparms (TYPE_ARG_TYPES (TREE_TYPE (fn)), decl_arg_types)) /* They match! */ candidates = tree_cons (NULL_TREE, fn, candidates); } } if (templates && TREE_CHAIN (templates)) { /* We have: [temp.expl.spec] It is possible for a specialization with a given function signature to be instantiated from more than one function template. In such cases, explicit specification of the template arguments must be used to uniquely identify the function template specialization being specialized. Note that here, there's no suggestion that we're supposed to determine which of the candidate templates is most specialized. However, we, also have: [temp.func.order] Partial ordering of overloaded function template declarations is used in the following contexts to select the function template to which a function template specialization refers: -- when an explicit specialization refers to a function template. So, we do use the partial ordering rules, at least for now. This extension can only serve to make invalid programs valid, so it's safe. And, there is strong anecdotal evidence that the committee intended the partial ordering rules to apply; the EDG front end has that behavior, and John Spicer claims that the committee simply forgot to delete the wording in [temp.expl.spec]. */ tree tmpl = most_specialized_instantiation (templates); if (tmpl != error_mark_node) { templates = tmpl; TREE_CHAIN (templates) = NULL_TREE; } } if (templates == NULL_TREE && candidates == NULL_TREE) { error ("template-id %qD for %q+D does not match any template " "declaration", template_id, decl); if (header_count && header_count != template_count + 1) inform (input_location, "saw %d %<template<>%>, need %d for " "specializing a member function template", header_count, template_count + 1); return error_mark_node; } else if ((templates && TREE_CHAIN (templates)) || (candidates && TREE_CHAIN (candidates)) || (templates && candidates)) { error ("ambiguous template specialization %qD for %q+D", template_id, decl); candidates = chainon (candidates, templates); print_candidates (candidates); return error_mark_node; } /* We have one, and exactly one, match. */ if (candidates) { tree fn = TREE_VALUE (candidates); *targs_out = copy_node (DECL_TI_ARGS (fn)); /* DECL is a re-declaration or partial instantiation of a template function. */ if (TREE_CODE (fn) == TEMPLATE_DECL) return fn; /* It was a specialization of an ordinary member function in a template class. */ return DECL_TI_TEMPLATE (fn); } /* It was a specialization of a template. */ targs = DECL_TI_ARGS (DECL_TEMPLATE_RESULT (TREE_VALUE (templates))); if (TMPL_ARGS_HAVE_MULTIPLE_LEVELS (targs)) { *targs_out = copy_node (targs); SET_TMPL_ARGS_LEVEL (*targs_out, TMPL_ARGS_DEPTH (*targs_out), TREE_PURPOSE (templates)); } else *targs_out = TREE_PURPOSE (templates); return TREE_VALUE (templates); } /* Returns a chain of parameter types, exactly like the SPEC_TYPES, but with the default argument values filled in from those in the TMPL_TYPES. */ static tree copy_default_args_to_explicit_spec_1 (tree spec_types, tree tmpl_types) { tree new_spec_types; if (!spec_types) return NULL_TREE; if (spec_types == void_list_node) return void_list_node; /* Substitute into the rest of the list. */ new_spec_types = copy_default_args_to_explicit_spec_1 (TREE_CHAIN (spec_types), TREE_CHAIN (tmpl_types)); /* Add the default argument for this parameter. */ return hash_tree_cons (TREE_PURPOSE (tmpl_types), TREE_VALUE (spec_types), new_spec_types); } /* DECL is an explicit specialization. Replicate default arguments from the template it specializes. (That way, code like: template <class T> void f(T = 3); template <> void f(double); void g () { f (); } works, as required.) An alternative approach would be to look up the correct default arguments at the call-site, but this approach is consistent with how implicit instantiations are handled. */ static void copy_default_args_to_explicit_spec (tree decl) { tree tmpl; tree spec_types; tree tmpl_types; tree new_spec_types; tree old_type; tree new_type; tree t; tree object_type = NULL_TREE; tree in_charge = NULL_TREE; tree vtt = NULL_TREE; /* See if there's anything we need to do. */ tmpl = DECL_TI_TEMPLATE (decl); tmpl_types = TYPE_ARG_TYPES (TREE_TYPE (DECL_TEMPLATE_RESULT (tmpl))); for (t = tmpl_types; t; t = TREE_CHAIN (t)) if (TREE_PURPOSE (t)) break; if (!t) return; old_type = TREE_TYPE (decl); spec_types = TYPE_ARG_TYPES (old_type); if (DECL_NONSTATIC_MEMBER_FUNCTION_P (decl)) { /* Remove the this pointer, but remember the object's type for CV quals. */ object_type = TREE_TYPE (TREE_VALUE (spec_types)); spec_types = TREE_CHAIN (spec_types); tmpl_types = TREE_CHAIN (tmpl_types); if (DECL_HAS_IN_CHARGE_PARM_P (decl)) { /* DECL may contain more parameters than TMPL due to the extra in-charge parameter in constructors and destructors. */ in_charge = spec_types; spec_types = TREE_CHAIN (spec_types); } if (DECL_HAS_VTT_PARM_P (decl)) { vtt = spec_types; spec_types = TREE_CHAIN (spec_types); } } /* Compute the merged default arguments. */ new_spec_types = copy_default_args_to_explicit_spec_1 (spec_types, tmpl_types); /* Compute the new FUNCTION_TYPE. */ if (object_type) { if (vtt) new_spec_types = hash_tree_cons (TREE_PURPOSE (vtt), TREE_VALUE (vtt), new_spec_types); if (in_charge) /* Put the in-charge parameter back. */ new_spec_types = hash_tree_cons (TREE_PURPOSE (in_charge), TREE_VALUE (in_charge), new_spec_types); new_type = build_method_type_directly (object_type, TREE_TYPE (old_type), new_spec_types); } else new_type = build_function_type (TREE_TYPE (old_type), new_spec_types); new_type = cp_build_type_attribute_variant (new_type, TYPE_ATTRIBUTES (old_type)); new_type = build_exception_variant (new_type, TYPE_RAISES_EXCEPTIONS (old_type)); TREE_TYPE (decl) = new_type; } /* Check to see if the function just declared, as indicated in DECLARATOR, and in DECL, is a specialization of a function template. We may also discover that the declaration is an explicit instantiation at this point. Returns DECL, or an equivalent declaration that should be used instead if all goes well. Issues an error message if something is amiss. Returns error_mark_node if the error is not easily recoverable. FLAGS is a bitmask consisting of the following flags: 2: The function has a definition. 4: The function is a friend. The TEMPLATE_COUNT is the number of references to qualifying template classes that appeared in the name of the function. For example, in template <class T> struct S { void f(); }; void S<int>::f(); the TEMPLATE_COUNT would be 1. However, explicitly specialized classes are not counted in the TEMPLATE_COUNT, so that in template <class T> struct S {}; template <> struct S<int> { void f(); } template <> void S<int>::f(); the TEMPLATE_COUNT would be 0. (Note that this declaration is invalid; there should be no template <>.) If the function is a specialization, it is marked as such via DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO is set up correctly, and it is added to the list of specializations for that template. */ tree check_explicit_specialization (tree declarator, tree decl, int template_count, int flags) { int have_def = flags & 2; int is_friend = flags & 4; int specialization = 0; int explicit_instantiation = 0; int member_specialization = 0; tree ctype = DECL_CLASS_CONTEXT (decl); tree dname = DECL_NAME (decl); tmpl_spec_kind tsk; if (is_friend) { if (!processing_specialization) tsk = tsk_none; else tsk = tsk_excessive_parms; } else tsk = current_tmpl_spec_kind (template_count); switch (tsk) { case tsk_none: if (processing_specialization) { specialization = 1; SET_DECL_TEMPLATE_SPECIALIZATION (decl); } else if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR) { if (is_friend) /* This could be something like: template <class T> void f(T); class S { friend void f<>(int); } */ specialization = 1; else { /* This case handles bogus declarations like template <> template <class T> void f<int>(); */ error ("template-id %qD in declaration of primary template", declarator); return decl; } } break; case tsk_invalid_member_spec: /* The error has already been reported in check_specialization_scope. */ return error_mark_node; case tsk_invalid_expl_inst: error ("template parameter list used in explicit instantiation"); /* Fall through. */ case tsk_expl_inst: if (have_def) error ("definition provided for explicit instantiation"); explicit_instantiation = 1; break; case tsk_excessive_parms: case tsk_insufficient_parms: if (tsk == tsk_excessive_parms) error ("too many template parameter lists in declaration of %qD", decl); else if (template_header_count) error("too few template parameter lists in declaration of %qD", decl); else error("explicit specialization of %qD must be introduced by " "%<template <>%>", decl); /* Fall through. */ case tsk_expl_spec: SET_DECL_TEMPLATE_SPECIALIZATION (decl); if (ctype) member_specialization = 1; else specialization = 1; break; case tsk_template: if (TREE_CODE (declarator) == TEMPLATE_ID_EXPR) { /* This case handles bogus declarations like template <> template <class T> void f<int>(); */ if (uses_template_parms (declarator)) error ("function template partial specialization %qD " "is not allowed", declarator); else error ("template-id %qD in declaration of primary template", declarator); return decl; } if (ctype && CLASSTYPE_TEMPLATE_INSTANTIATION (ctype)) /* This is a specialization of a member template, without specialization the containing class. Something like: template <class T> struct S { template <class U> void f (U); }; template <> template <class U> void S<int>::f(U) {} That's a specialization -- but of the entire template. */ specialization = 1; break; default: gcc_unreachable (); } if (specialization || member_specialization) { tree t = TYPE_ARG_TYPES (TREE_TYPE (decl)); for (; t; t = TREE_CHAIN (t)) if (TREE_PURPOSE (t)) { permerror (input_location, "default argument specified in explicit specialization"); break; } } if (specialization || member_specialization || explicit_instantiation) { tree tmpl = NULL_TREE; tree targs = NULL_TREE; /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */ if (TREE_CODE (declarator) != TEMPLATE_ID_EXPR) { tree fns; gcc_assert (TREE_CODE (declarator) == IDENTIFIER_NODE); if (ctype) fns = dname; else { /* If there is no class context, the explicit instantiation must be at namespace scope. */ gcc_assert (DECL_NAMESPACE_SCOPE_P (decl)); /* Find the namespace binding, using the declaration context. */ fns = lookup_qualified_name (CP_DECL_CONTEXT (decl), dname, false, true); if (fns == error_mark_node || !is_overloaded_fn (fns)) { error ("%qD is not a template function", dname); fns = error_mark_node; } else { tree fn = OVL_CURRENT (fns); if (!is_associated_namespace (CP_DECL_CONTEXT (decl), CP_DECL_CONTEXT (fn))) error ("%qD is not declared in %qD", decl, current_namespace); } } declarator = lookup_template_function (fns, NULL_TREE); } if (declarator == error_mark_node) return error_mark_node; if (ctype != NULL_TREE && TYPE_BEING_DEFINED (ctype)) { if (!explicit_instantiation) /* A specialization in class scope. This is invalid, but the error will already have been flagged by check_specialization_scope. */ return error_mark_node; else { /* It's not valid to write an explicit instantiation in class scope, e.g.: class C { template void f(); } This case is caught by the parser. However, on something like: template class C { void f(); }; (which is invalid) we can get here. The error will be issued later. */ ; } return decl; } else if (ctype != NULL_TREE && (TREE_CODE (TREE_OPERAND (declarator, 0)) == IDENTIFIER_NODE)) { /* Find the list of functions in ctype that have the same name as the declared function. */ tree name = TREE_OPERAND (declarator, 0); tree fns = NULL_TREE; int idx; if (constructor_name_p (name, ctype)) { int is_constructor = DECL_CONSTRUCTOR_P (decl); if (is_constructor ? !TYPE_HAS_USER_CONSTRUCTOR (ctype) : !CLASSTYPE_DESTRUCTORS (ctype)) { /* From [temp.expl.spec]: If such an explicit specialization for the member of a class template names an implicitly-declared special member function (clause _special_), the program is ill-formed. Similar language is found in [temp.explicit]. */ error ("specialization of implicitly-declared special member function"); return error_mark_node; } name = is_constructor ? ctor_identifier : dtor_identifier; } if (!DECL_CONV_FN_P (decl)) { idx = lookup_fnfields_1 (ctype, name); if (idx >= 0) fns = VEC_index (tree, CLASSTYPE_METHOD_VEC (ctype), idx); } else { VEC(tree,gc) *methods; tree ovl; /* For a type-conversion operator, we cannot do a name-based lookup. We might be looking for `operator int' which will be a specialization of `operator T'. So, we find *all* the conversion operators, and then select from them. */ fns = NULL_TREE; methods = CLASSTYPE_METHOD_VEC (ctype); if (methods) for (idx = CLASSTYPE_FIRST_CONVERSION_SLOT; VEC_iterate (tree, methods, idx, ovl); ++idx) { if (!DECL_CONV_FN_P (OVL_CURRENT (ovl))) /* There are no more conversion functions. */ break; /* Glue all these conversion functions together with those we already have. */ for (; ovl; ovl = OVL_NEXT (ovl)) fns = ovl_cons (OVL_CURRENT (ovl), fns); } } if (fns == NULL_TREE) { error ("no member function %qD declared in %qT", name, ctype); return error_mark_node; } else TREE_OPERAND (declarator, 0) = fns; } /* Figure out what exactly is being specialized at this point. Note that for an explicit instantiation, even one for a member function, we cannot tell apriori whether the instantiation is for a member template, or just a member function of a template class. Even if a member template is being instantiated, the member template arguments may be elided if they can be deduced from the rest of the declaration. */ tmpl = determine_specialization (declarator, decl, &targs, member_specialization, template_count, tsk); if (!tmpl || tmpl == error_mark_node) /* We couldn't figure out what this declaration was specializing. */ return error_mark_node; else { tree gen_tmpl = most_general_template (tmpl); if (explicit_instantiation) { /* We don't set DECL_EXPLICIT_INSTANTIATION here; that is done by do_decl_instantiation later. */ int arg_depth = TMPL_ARGS_DEPTH (targs); int parm_depth = TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (tmpl)); if (arg_depth > parm_depth) { /* If TMPL is not the most general template (for example, if TMPL is a friend template that is injected into namespace scope), then there will be too many levels of TARGS. Remove some of them here. */ int i; tree new_targs; new_targs = make_tree_vec (parm_depth); for (i = arg_depth - parm_depth; i < arg_depth; ++i) TREE_VEC_ELT (new_targs, i - (arg_depth - parm_depth)) = TREE_VEC_ELT (targs, i); targs = new_targs; } return instantiate_template (tmpl, targs, tf_error); } /* If we thought that the DECL was a member function, but it turns out to be specializing a static member function, make DECL a static member function as well. */ if (DECL_STATIC_FUNCTION_P (tmpl) && DECL_NONSTATIC_MEMBER_FUNCTION_P (decl)) revert_static_member_fn (decl); /* If this is a specialization of a member template of a template class, we want to return the TEMPLATE_DECL, not the specialization of it. */ if (tsk == tsk_template) { tree result = DECL_TEMPLATE_RESULT (tmpl); SET_DECL_TEMPLATE_SPECIALIZATION (tmpl); DECL_INITIAL (result) = NULL_TREE; if (have_def) { tree parm; DECL_SOURCE_LOCATION (tmpl) = DECL_SOURCE_LOCATION (decl); DECL_SOURCE_LOCATION (result) = DECL_SOURCE_LOCATION (decl); /* We want to use the argument list specified in the definition, not in the original declaration. */ DECL_ARGUMENTS (result) = DECL_ARGUMENTS (decl); for (parm = DECL_ARGUMENTS (result); parm; parm = TREE_CHAIN (parm)) DECL_CONTEXT (parm) = result; } return register_specialization (tmpl, gen_tmpl, targs, is_friend, 0); } /* Set up the DECL_TEMPLATE_INFO for DECL. */ DECL_TEMPLATE_INFO (decl) = build_template_info (tmpl, targs); /* Inherit default function arguments from the template DECL is specializing. */ copy_default_args_to_explicit_spec (decl); /* This specialization has the same protection as the template it specializes. */ TREE_PRIVATE (decl) = TREE_PRIVATE (gen_tmpl); TREE_PROTECTED (decl) = TREE_PROTECTED (gen_tmpl); /* 7.1.1-1 [dcl.stc] A storage-class-specifier shall not be specified in an explicit specialization... The parser rejects these, so unless action is taken here, explicit function specializations will always appear with global linkage. The action recommended by the C++ CWG in response to C++ defect report 605 is to make the storage class and linkage of the explicit specialization match the templated function: http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605 */ if (tsk == tsk_expl_spec && DECL_FUNCTION_TEMPLATE_P (gen_tmpl)) { tree tmpl_func = DECL_TEMPLATE_RESULT (gen_tmpl); gcc_assert (TREE_CODE (tmpl_func) == FUNCTION_DECL); /* This specialization has the same linkage and visibility as the function template it specializes. */ TREE_PUBLIC (decl) = TREE_PUBLIC (tmpl_func); if (! TREE_PUBLIC (decl)) { DECL_INTERFACE_KNOWN (decl) = 1; DECL_NOT_REALLY_EXTERN (decl) = 1; } DECL_THIS_STATIC (decl) = DECL_THIS_STATIC (tmpl_func); if (DECL_VISIBILITY_SPECIFIED (tmpl_func)) { DECL_VISIBILITY_SPECIFIED (decl) = 1; DECL_VISIBILITY (decl) = DECL_VISIBILITY (tmpl_func); } } /* If DECL is a friend declaration, declared using an unqualified name, the namespace associated with DECL may have been set incorrectly. For example, in: template <typename T> void f(T); namespace N { struct S { friend void f<int>(int); } } we will have set the DECL_CONTEXT for the friend declaration to N, rather than to the global namespace. */ if (DECL_NAMESPACE_SCOPE_P (decl)) DECL_CONTEXT (decl) = DECL_CONTEXT (tmpl); if (is_friend && !have_def) /* This is not really a declaration of a specialization. It's just the name of an instantiation. But, it's not a request for an instantiation, either. */ SET_DECL_IMPLICIT_INSTANTIATION (decl); else if (DECL_CONSTRUCTOR_P (decl) || DECL_DESTRUCTOR_P (decl)) /* This is indeed a specialization. In case of constructors and destructors, we need in-charge and not-in-charge versions in V3 ABI. */ clone_function_decl (decl, /*update_method_vec_p=*/0); /* Register this specialization so that we can find it again. */ decl = register_specialization (decl, gen_tmpl, targs, is_friend, 0); } } return decl; } /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template parameters. These are represented in the same format used for DECL_TEMPLATE_PARMS. */ int comp_template_parms (const_tree parms1, const_tree parms2) { const_tree p1; const_tree p2; if (parms1 == parms2) return 1; for (p1 = parms1, p2 = parms2; p1 != NULL_TREE && p2 != NULL_TREE; p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2)) { tree t1 = TREE_VALUE (p1); tree t2 = TREE_VALUE (p2); int i; gcc_assert (TREE_CODE (t1) == TREE_VEC); gcc_assert (TREE_CODE (t2) == TREE_VEC); if (TREE_VEC_LENGTH (t1) != TREE_VEC_LENGTH (t2)) return 0; for (i = 0; i < TREE_VEC_LENGTH (t2); ++i) { tree parm1 = TREE_VALUE (TREE_VEC_ELT (t1, i)); tree parm2 = TREE_VALUE (TREE_VEC_ELT (t2, i)); /* If either of the template parameters are invalid, assume they match for the sake of error recovery. */ if (parm1 == error_mark_node || parm2 == error_mark_node) return 1; if (TREE_CODE (parm1) != TREE_CODE (parm2)) return 0; if (TREE_CODE (parm1) == TEMPLATE_TYPE_PARM && (TEMPLATE_TYPE_PARAMETER_PACK (parm1) == TEMPLATE_TYPE_PARAMETER_PACK (parm2))) continue; else if (!same_type_p (TREE_TYPE (parm1), TREE_TYPE (parm2))) return 0; } } if ((p1 != NULL_TREE) != (p2 != NULL_TREE)) /* One set of parameters has more parameters lists than the other. */ return 0; return 1; } /* Determine whether PARM is a parameter pack. */ bool template_parameter_pack_p (const_tree parm) { /* Determine if we have a non-type template parameter pack. */ if (TREE_CODE (parm) == PARM_DECL) return (DECL_TEMPLATE_PARM_P (parm) && TEMPLATE_PARM_PARAMETER_PACK (DECL_INITIAL (parm))); /* If this is a list of template parameters, we could get a TYPE_DECL or a TEMPLATE_DECL. */ if (TREE_CODE (parm) == TYPE_DECL || TREE_CODE (parm) == TEMPLATE_DECL) parm = TREE_TYPE (parm); return ((TREE_CODE (parm) == TEMPLATE_TYPE_PARM || TREE_CODE (parm) == TEMPLATE_TEMPLATE_PARM) && TEMPLATE_TYPE_PARAMETER_PACK (parm)); } /* Determine if T is a function parameter pack. */ bool function_parameter_pack_p (const_tree t) { if (t && TREE_CODE (t) == PARM_DECL) return FUNCTION_PARAMETER_PACK_P (t); return false; } /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST. PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */ tree get_function_template_decl (const_tree primary_func_tmpl_inst) { if (! primary_func_tmpl_inst || TREE_CODE (primary_func_tmpl_inst) != FUNCTION_DECL || ! primary_template_instantiation_p (primary_func_tmpl_inst)) return NULL; return DECL_TEMPLATE_RESULT (DECL_TI_TEMPLATE (primary_func_tmpl_inst)); } /* Return true iff the function parameter PARAM_DECL was expanded from the function parameter pack PACK. */ bool function_parameter_expanded_from_pack_p (tree param_decl, tree pack) { if (DECL_ARTIFICIAL (param_decl) || !function_parameter_pack_p (pack)) return false; /* The parameter pack and its pack arguments have the same DECL_PARM_INDEX. */ return DECL_PARM_INDEX (pack) == DECL_PARM_INDEX (param_decl); } /* Determine whether ARGS describes a variadic template args list, i.e., one that is terminated by a template argument pack. */ static bool template_args_variadic_p (tree args) { int nargs; tree last_parm; if (args == NULL_TREE) return false; args = INNERMOST_TEMPLATE_ARGS (args); nargs = TREE_VEC_LENGTH (args); if (nargs == 0) return false; last_parm = TREE_VEC_ELT (args, nargs - 1); return ARGUMENT_PACK_P (last_parm); } /* Generate a new name for the parameter pack name NAME (an IDENTIFIER_NODE) that incorporates its */ static tree make_ith_pack_parameter_name (tree name, int i) { /* Munge the name to include the parameter index. */ #define NUMBUF_LEN 128 char numbuf[NUMBUF_LEN]; char* newname; int newname_len; snprintf (numbuf, NUMBUF_LEN, "%i", i); newname_len = IDENTIFIER_LENGTH (name) + strlen (numbuf) + 2; newname = (char*)alloca (newname_len); snprintf (newname, newname_len, "%s#%i", IDENTIFIER_POINTER (name), i); return get_identifier (newname); } /* Return true if T is a primary function or class template instantiation. */ bool primary_template_instantiation_p (const_tree t) { if (!t) return false; if (TREE_CODE (t) == FUNCTION_DECL) return DECL_LANG_SPECIFIC (t) && DECL_TEMPLATE_INSTANTIATION (t) && PRIMARY_TEMPLATE_P (DECL_TI_TEMPLATE (t)); else if (CLASS_TYPE_P (t)) return CLASSTYPE_TEMPLATE_INSTANTIATION (t) && PRIMARY_TEMPLATE_P (CLASSTYPE_TI_TEMPLATE (t)); return false; } /* Return true if PARM is a template template parameter. */ bool template_template_parameter_p (const_tree parm) { return DECL_TEMPLATE_TEMPLATE_PARM_P (parm); } /* Return the template parameters of T if T is a primary template instantiation, NULL otherwise. */ tree get_primary_template_innermost_parameters (const_tree t) { tree parms = NULL, template_info = NULL; if ((template_info = get_template_info (t)) && primary_template_instantiation_p (t)) parms = INNERMOST_TEMPLATE_PARMS (DECL_TEMPLATE_PARMS (TI_TEMPLATE (template_info))); return parms; } /* Return the template parameters of the LEVELth level from the full list of template parameters PARMS. */ tree get_template_parms_at_level (tree parms, int level) { tree p; if (!parms || TREE_CODE (parms) != TREE_LIST || level > TMPL_PARMS_DEPTH (parms)) return NULL_TREE; for (p = parms; p; p = TREE_CHAIN (p)) if (TMPL_PARMS_DEPTH (p) == level) return p; return NULL_TREE; } /* Returns the template arguments of T if T is a template instantiation, NULL otherwise. */ tree get_template_innermost_arguments (const_tree t) { tree args = NULL, template_info = NULL; if ((template_info = get_template_info (t)) && TI_ARGS (template_info)) args = INNERMOST_TEMPLATE_ARGS (TI_ARGS (template_info)); return args; } /* Return the argument pack elements of T if T is a template argument pack, NULL otherwise. */ tree get_template_argument_pack_elems (const_tree t) { if (TREE_CODE (t) != TYPE_ARGUMENT_PACK && TREE_CODE (t) != NONTYPE_ARGUMENT_PACK) return NULL; return ARGUMENT_PACK_ARGS (t); } /* Structure used to track the progress of find_parameter_packs_r. */ struct find_parameter_pack_data { /* TREE_LIST that will contain all of the parameter packs found by the traversal. */ tree* parameter_packs; /* Set of AST nodes that have been visited by the traversal. */ struct pointer_set_t *visited; }; /* Identifies all of the argument packs that occur in a template argument and appends them to the TREE_LIST inside DATA, which is a find_parameter_pack_data structure. This is a subroutine of make_pack_expansion and uses_parameter_packs. */ static tree find_parameter_packs_r (tree *tp, int *walk_subtrees, void* data) { tree t = *tp; struct find_parameter_pack_data* ppd = (struct find_parameter_pack_data*)data; bool parameter_pack_p = false; /* Identify whether this is a parameter pack or not. */ switch (TREE_CODE (t)) { case TEMPLATE_PARM_INDEX: if (TEMPLATE_PARM_PARAMETER_PACK (t)) parameter_pack_p = true; break; case TEMPLATE_TYPE_PARM: case TEMPLATE_TEMPLATE_PARM: if (TEMPLATE_TYPE_PARAMETER_PACK (t)) parameter_pack_p = true; break; case PARM_DECL: if (FUNCTION_PARAMETER_PACK_P (t)) { /* We don't want to walk into the type of a PARM_DECL, because we don't want to see the type parameter pack. */ *walk_subtrees = 0; parameter_pack_p = true; } break; default: /* Not a parameter pack. */ break; } if (parameter_pack_p) { /* Add this parameter pack to the list. */ *ppd->parameter_packs = tree_cons (NULL_TREE, t, *ppd->parameter_packs); } if (TYPE_P (t)) cp_walk_tree (&TYPE_CONTEXT (t), &find_parameter_packs_r, ppd, ppd->visited); /* This switch statement will return immediately if we don't find a parameter pack. */ switch (TREE_CODE (t)) { case TEMPLATE_PARM_INDEX: return NULL_TREE; case BOUND_TEMPLATE_TEMPLATE_PARM: /* Check the template itself. */ cp_walk_tree (&TREE_TYPE (TYPE_TI_TEMPLATE (t)), &find_parameter_packs_r, ppd, ppd->visited); /* Check the template arguments. */ cp_walk_tree (&TYPE_TI_ARGS (t), &find_parameter_packs_r, ppd, ppd->visited); *walk_subtrees = 0; return NULL_TREE; case TEMPLATE_TYPE_PARM: case TEMPLATE_TEMPLATE_PARM: return NULL_TREE; case PARM_DECL: return NULL_TREE; case RECORD_TYPE: if (TYPE_PTRMEMFUNC_P (t)) return NULL_TREE; /* Fall through. */ case UNION_TYPE: case ENUMERAL_TYPE: if (TYPE_TEMPLATE_INFO (t)) cp_walk_tree (&TI_ARGS (TYPE_TEMPLATE_INFO (t)), &find_parameter_packs_r, ppd, ppd->visited); *walk_subtrees = 0; return NULL_TREE; case TEMPLATE_DECL: cp_walk_tree (&TREE_TYPE (t), &find_parameter_packs_r, ppd, ppd->visited); return NULL_TREE; case TYPENAME_TYPE: cp_walk_tree (&TYPENAME_TYPE_FULLNAME (t), &find_parameter_packs_r, ppd, ppd->visited); *walk_subtrees = 0; return NULL_TREE; case TYPE_PACK_EXPANSION: case EXPR_PACK_EXPANSION: *walk_subtrees = 0; return NULL_TREE; case INTEGER_TYPE: cp_walk_tree (&TYPE_MAX_VALUE (t), &find_parameter_packs_r, ppd, ppd->visited); *walk_subtrees = 0; return NULL_TREE; case IDENTIFIER_NODE: cp_walk_tree (&TREE_TYPE (t), &find_parameter_packs_r, ppd, ppd->visited); *walk_subtrees = 0; return NULL_TREE; default: return NULL_TREE; } return NULL_TREE; } /* Determines if the expression or type T uses any parameter packs. */ bool uses_parameter_packs (tree t) { tree parameter_packs = NULL_TREE; struct find_parameter_pack_data ppd; ppd.parameter_packs = ¶meter_packs; ppd.visited = pointer_set_create (); cp_walk_tree (&t, &find_parameter_packs_r, &ppd, ppd.visited); pointer_set_destroy (ppd.visited); return parameter_packs != NULL_TREE; } /* Turn ARG, which may be an expression, type, or a TREE_LIST representation a base-class initializer into a parameter pack expansion. If all goes well, the resulting node will be an EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST, respectively. */ tree make_pack_expansion (tree arg) { tree result; tree parameter_packs = NULL_TREE; bool for_types = false; struct find_parameter_pack_data ppd; if (!arg || arg == error_mark_node) return arg; if (TREE_CODE (arg) == TREE_LIST) { /* The only time we will see a TREE_LIST here is for a base class initializer. In this case, the TREE_PURPOSE will be a _TYPE node (representing the base class expansion we're initializing) and the TREE_VALUE will be a TREE_LIST containing the initialization arguments. The resulting expansion looks somewhat different from most expansions. Rather than returning just one _EXPANSION, we return a TREE_LIST whose TREE_PURPOSE is a TYPE_PACK_EXPANSION containing the bases that will be initialized. The TREE_VALUE will be identical to the original TREE_VALUE, which is a list of arguments that will be passed to each base. We do not introduce any new pack expansion nodes into the TREE_VALUE (although it is possible that some already exist), because the TREE_PURPOSE and TREE_VALUE all need to be expanded together with the same _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the resulting TREE_PURPOSE will mention the parameter packs in both the bases and the arguments to the bases. */ tree purpose; tree value; tree parameter_packs = NULL_TREE; /* Determine which parameter packs will be used by the base class expansion. */ ppd.visited = pointer_set_create (); ppd.parameter_packs = ¶meter_packs; cp_walk_tree (&TREE_PURPOSE (arg), &find_parameter_packs_r, &ppd, ppd.visited); if (parameter_packs == NULL_TREE) { error ("base initializer expansion %<%T%> contains no parameter packs", arg); pointer_set_destroy (ppd.visited); return error_mark_node; } if (TREE_VALUE (arg) != void_type_node) { /* Collect the sets of parameter packs used in each of the initialization arguments. */ for (value = TREE_VALUE (arg); value; value = TREE_CHAIN (value)) { /* Determine which parameter packs will be expanded in this argument. */ cp_walk_tree (&TREE_VALUE (value), &find_parameter_packs_r, &ppd, ppd.visited); } } pointer_set_destroy (ppd.visited); /* Create the pack expansion type for the base type. */ purpose = cxx_make_type (TYPE_PACK_EXPANSION); SET_PACK_EXPANSION_PATTERN (purpose, TREE_PURPOSE (arg)); PACK_EXPANSION_PARAMETER_PACKS (purpose) = parameter_packs; /* Just use structural equality for these TYPE_PACK_EXPANSIONS; they will rarely be compared to anything. */ SET_TYPE_STRUCTURAL_EQUALITY (purpose); return tree_cons (purpose, TREE_VALUE (arg), NULL_TREE); } if (TYPE_P (arg) || TREE_CODE (arg) == TEMPLATE_DECL) for_types = true; /* Build the PACK_EXPANSION_* node. */ result = for_types ? cxx_make_type (TYPE_PACK_EXPANSION) : make_node (EXPR_PACK_EXPANSION); SET_PACK_EXPANSION_PATTERN (result, arg); if (TREE_CODE (result) == EXPR_PACK_EXPANSION) { /* Propagate type and const-expression information. */ TREE_TYPE (result) = TREE_TYPE (arg); TREE_CONSTANT (result) = TREE_CONSTANT (arg); } else /* Just use structural equality for these TYPE_PACK_EXPANSIONS; they will rarely be compared to anything. */ SET_TYPE_STRUCTURAL_EQUALITY (result); /* Determine which parameter packs will be expanded. */ ppd.parameter_packs = ¶meter_packs; ppd.visited = pointer_set_create (); cp_walk_tree (&arg, &find_parameter_packs_r, &ppd, ppd.visited); pointer_set_destroy (ppd.visited); /* Make sure we found some parameter packs. */ if (parameter_packs == NULL_TREE) { if (TYPE_P (arg)) error ("expansion pattern %<%T%> contains no argument packs", arg); else error ("expansion pattern %<%E%> contains no argument packs", arg); return error_mark_node; } PACK_EXPANSION_PARAMETER_PACKS (result) = parameter_packs; return result; } /* Checks T for any "bare" parameter packs, which have not yet been expanded, and issues an error if any are found. This operation can only be done on full expressions or types (e.g., an expression statement, "if" condition, etc.), because we could have expressions like: foo(f(g(h(args)))...) where "args" is a parameter pack. check_for_bare_parameter_packs should not be called for the subexpressions args, h(args), g(h(args)), or f(g(h(args))), because we would produce erroneous error messages. Returns TRUE and emits an error if there were bare parameter packs, returns FALSE otherwise. */ bool check_for_bare_parameter_packs (tree t) { tree parameter_packs = NULL_TREE; struct find_parameter_pack_data ppd; if (!processing_template_decl || !t || t == error_mark_node) return false; if (TREE_CODE (t) == TYPE_DECL) t = TREE_TYPE (t); ppd.parameter_packs = ¶meter_packs; ppd.visited = pointer_set_create (); cp_walk_tree (&t, &find_parameter_packs_r, &ppd, ppd.visited); pointer_set_destroy (ppd.visited); if (parameter_packs) { error ("parameter packs not expanded with %<...%>:"); while (parameter_packs) { tree pack = TREE_VALUE (parameter_packs); tree name = NULL_TREE; if (TREE_CODE (pack) == TEMPLATE_TYPE_PARM || TREE_CODE (pack) == TEMPLATE_TEMPLATE_PARM) name = TYPE_NAME (pack); else if (TREE_CODE (pack) == TEMPLATE_PARM_INDEX) name = DECL_NAME (TEMPLATE_PARM_DECL (pack)); else name = DECL_NAME (pack); if (name) inform (input_location, " %qD", name); else inform (input_location, " <anonymous>"); parameter_packs = TREE_CHAIN (parameter_packs); } return true; } return false; } /* Expand any parameter packs that occur in the template arguments in ARGS. */ tree expand_template_argument_pack (tree args) { tree result_args = NULL_TREE; int in_arg, out_arg = 0, nargs = args ? TREE_VEC_LENGTH (args) : 0; int num_result_args = -1; int non_default_args_count = -1; /* First, determine if we need to expand anything, and the number of slots we'll need. */ for (in_arg = 0; in_arg < nargs; ++in_arg) { tree arg = TREE_VEC_ELT (args, in_arg); if (arg == NULL_TREE) return args; if (ARGUMENT_PACK_P (arg)) { int num_packed = TREE_VEC_LENGTH (ARGUMENT_PACK_ARGS (arg)); if (num_result_args < 0) num_result_args = in_arg + num_packed; else num_result_args += num_packed; } else { if (num_result_args >= 0) num_result_args++; } } /* If no expansion is necessary, we're done. */ if (num_result_args < 0) return args; /* Expand arguments. */ result_args = make_tree_vec (num_result_args); if (NON_DEFAULT_TEMPLATE_ARGS_COUNT (args)) non_default_args_count = GET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (args); for (in_arg = 0; in_arg < nargs; ++in_arg) { tree arg = TREE_VEC_ELT (args, in_arg); if (ARGUMENT_PACK_P (arg)) { tree packed = ARGUMENT_PACK_ARGS (arg); int i, num_packed = TREE_VEC_LENGTH (packed); for (i = 0; i < num_packed; ++i, ++out_arg) TREE_VEC_ELT (result_args, out_arg) = TREE_VEC_ELT(packed, i); if (non_default_args_count > 0) non_default_args_count += num_packed; } else { TREE_VEC_ELT (result_args, out_arg) = arg; ++out_arg; } } if (non_default_args_count >= 0) SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (result_args, non_default_args_count); return result_args; } /* Checks if DECL shadows a template parameter. [temp.local]: A template-parameter shall not be redeclared within its scope (including nested scopes). Emits an error and returns TRUE if the DECL shadows a parameter, returns FALSE otherwise. */ bool check_template_shadow (tree decl) { tree olddecl; /* If we're not in a template, we can't possibly shadow a template parameter. */ if (!current_template_parms) return true; /* Figure out what we're shadowing. */ if (TREE_CODE (decl) == OVERLOAD) decl = OVL_CURRENT (decl); olddecl = innermost_non_namespace_value (DECL_NAME (decl)); /* If there's no previous binding for this name, we're not shadowing anything, let alone a template parameter. */ if (!olddecl) return true; /* If we're not shadowing a template parameter, we're done. Note that OLDDECL might be an OVERLOAD (or perhaps even an ERROR_MARK), so we can't just blithely assume it to be a _DECL node. */ if (!DECL_P (olddecl) || !DECL_TEMPLATE_PARM_P (olddecl)) return true; /* We check for decl != olddecl to avoid bogus errors for using a name inside a class. We check TPFI to avoid duplicate errors for inline member templates. */ if (decl == olddecl || TEMPLATE_PARMS_FOR_INLINE (current_template_parms)) return true; error ("declaration of %q+#D", decl); error (" shadows template parm %q+#D", olddecl); return false; } /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL, ORIG_LEVEL, DECL, and TYPE. */ static tree build_template_parm_index (int index, int level, int orig_level, tree decl, tree type) { tree t = make_node (TEMPLATE_PARM_INDEX); TEMPLATE_PARM_IDX (t) = index; TEMPLATE_PARM_LEVEL (t) = level; TEMPLATE_PARM_ORIG_LEVEL (t) = orig_level; TEMPLATE_PARM_DECL (t) = decl; TREE_TYPE (t) = type; TREE_CONSTANT (t) = TREE_CONSTANT (decl); TREE_READONLY (t) = TREE_READONLY (decl); return t; } /* Find the canonical type parameter for the given template type parameter. Returns the canonical type parameter, which may be TYPE if no such parameter existed. */ static tree canonical_type_parameter (tree type) { tree list; int idx = TEMPLATE_TYPE_IDX (type); if (!canonical_template_parms) canonical_template_parms = VEC_alloc (tree, gc, idx+1); while (VEC_length (tree, canonical_template_parms) <= (unsigned)idx) VEC_safe_push (tree, gc, canonical_template_parms, NULL_TREE); list = VEC_index (tree, canonical_template_parms, idx); while (list && !comptypes (type, TREE_VALUE (list), COMPARE_STRUCTURAL)) list = TREE_CHAIN (list); if (list) return TREE_VALUE (list); else { VEC_replace(tree, canonical_template_parms, idx, tree_cons (NULL_TREE, type, VEC_index (tree, canonical_template_parms, idx))); return type; } } /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a new one is created. */ static tree reduce_template_parm_level (tree index, tree type, int levels, tree args, tsubst_flags_t complain) { if (TEMPLATE_PARM_DESCENDANTS (index) == NULL_TREE || (TEMPLATE_PARM_LEVEL (TEMPLATE_PARM_DESCENDANTS (index)) != TEMPLATE_PARM_LEVEL (index) - levels) || !same_type_p (type, TREE_TYPE (TEMPLATE_PARM_DESCENDANTS (index)))) { tree orig_decl = TEMPLATE_PARM_DECL (index); tree decl, t; decl = build_decl (DECL_SOURCE_LOCATION (orig_decl), TREE_CODE (orig_decl), DECL_NAME (orig_decl), type); TREE_CONSTANT (decl) = TREE_CONSTANT (orig_decl); TREE_READONLY (decl) = TREE_READONLY (orig_decl); DECL_ARTIFICIAL (decl) = 1; SET_DECL_TEMPLATE_PARM_P (decl); t = build_template_parm_index (TEMPLATE_PARM_IDX (index), TEMPLATE_PARM_LEVEL (index) - levels, TEMPLATE_PARM_ORIG_LEVEL (index), decl, type); TEMPLATE_PARM_DESCENDANTS (index) = t; TEMPLATE_PARM_PARAMETER_PACK (t) = TEMPLATE_PARM_PARAMETER_PACK (index); /* Template template parameters need this. */ if (TREE_CODE (decl) == TEMPLATE_DECL) DECL_TEMPLATE_PARMS (decl) = tsubst_template_parms (DECL_TEMPLATE_PARMS (TEMPLATE_PARM_DECL (index)), args, complain); } return TEMPLATE_PARM_DESCENDANTS (index); } /* Process information from new template parameter PARM and append it to the LIST being built. This new parameter is a non-type parameter iff IS_NON_TYPE is true. This new parameter is a parameter pack iff IS_PARAMETER_PACK is true. The location of PARM is in PARM_LOC. */ tree process_template_parm (tree list, location_t parm_loc, tree parm, bool is_non_type, bool is_parameter_pack) { tree decl = 0; tree defval; tree err_parm_list; int idx = 0; gcc_assert (TREE_CODE (parm) == TREE_LIST); defval = TREE_PURPOSE (parm); if (list) { tree p = tree_last (list); if (p && TREE_VALUE (p) != error_mark_node) { p = TREE_VALUE (p); if (TREE_CODE (p) == TYPE_DECL || TREE_CODE (p) == TEMPLATE_DECL) idx = TEMPLATE_TYPE_IDX (TREE_TYPE (p)); else idx = TEMPLATE_PARM_IDX (DECL_INITIAL (p)); } ++idx; } else idx = 0; if (is_non_type) { parm = TREE_VALUE (parm); SET_DECL_TEMPLATE_PARM_P (parm); if (TREE_TYPE (parm) == error_mark_node) { err_parm_list = build_tree_list (defval, parm); TREE_VALUE (err_parm_list) = error_mark_node; return chainon (list, err_parm_list); } else { /* [temp.param] The top-level cv-qualifiers on the template-parameter are ignored when determining its type. */ TREE_TYPE (parm) = TYPE_MAIN_VARIANT (TREE_TYPE (parm)); if (invalid_nontype_parm_type_p (TREE_TYPE (parm), 1)) { err_parm_list = build_tree_list (defval, parm); TREE_VALUE (err_parm_list) = error_mark_node; return chainon (list, err_parm_list); } if (uses_parameter_packs (TREE_TYPE (parm)) && !is_parameter_pack) { /* This template parameter is not a parameter pack, but it should be. Complain about "bare" parameter packs. */ check_for_bare_parameter_packs (TREE_TYPE (parm)); /* Recover by calling this a parameter pack. */ is_parameter_pack = true; } } /* A template parameter is not modifiable. */ TREE_CONSTANT (parm) = 1; TREE_READONLY (parm) = 1; decl = build_decl (parm_loc, CONST_DECL, DECL_NAME (parm), TREE_TYPE (parm)); TREE_CONSTANT (decl) = 1; TREE_READONLY (decl) = 1; DECL_INITIAL (parm) = DECL_INITIAL (decl) = build_template_parm_index (idx, processing_template_decl, processing_template_decl, decl, TREE_TYPE (parm)); TEMPLATE_PARM_PARAMETER_PACK (DECL_INITIAL (parm)) = is_parameter_pack; } else { tree t; parm = TREE_VALUE (TREE_VALUE (parm)); if (parm && TREE_CODE (parm) == TEMPLATE_DECL) { t = cxx_make_type (TEMPLATE_TEMPLATE_PARM); /* This is for distinguishing between real templates and template template parameters */ TREE_TYPE (parm) = t; TREE_TYPE (DECL_TEMPLATE_RESULT (parm)) = t; decl = parm; } else { t = cxx_make_type (TEMPLATE_TYPE_PARM); /* parm is either IDENTIFIER_NODE or NULL_TREE. */ decl = build_decl (parm_loc, TYPE_DECL, parm, t); } TYPE_NAME (t) = decl; TYPE_STUB_DECL (t) = decl; parm = decl; TEMPLATE_TYPE_PARM_INDEX (t) = build_template_parm_index (idx, processing_template_decl, processing_template_decl, decl, TREE_TYPE (parm)); TEMPLATE_TYPE_PARAMETER_PACK (t) = is_parameter_pack; TYPE_CANONICAL (t) = canonical_type_parameter (t); } DECL_ARTIFICIAL (decl) = 1; SET_DECL_TEMPLATE_PARM_P (decl); pushdecl (decl); parm = build_tree_list (defval, parm); return chainon (list, parm); } /* The end of a template parameter list has been reached. Process the tree list into a parameter vector, converting each parameter into a more useful form. Type parameters are saved as IDENTIFIER_NODEs, and others as PARM_DECLs. */ tree end_template_parm_list (tree parms) { int nparms; tree parm, next; tree saved_parmlist = make_tree_vec (list_length (parms)); current_template_parms = tree_cons (size_int (processing_template_decl), saved_parmlist, current_template_parms); for (parm = parms, nparms = 0; parm; parm = next, nparms++) { next = TREE_CHAIN (parm); TREE_VEC_ELT (saved_parmlist, nparms) = parm; TREE_CHAIN (parm) = NULL_TREE; if (TREE_CODE (TREE_VALUE (parm)) == TYPE_DECL) TEMPLATE_TYPE_PARM_SIBLING_PARMS (TREE_TYPE (TREE_VALUE (parm))) = current_template_parms; } --processing_template_parmlist; return saved_parmlist; } /* end_template_decl is called after a template declaration is seen. */ void end_template_decl (void) { reset_specialization (); if (! processing_template_decl) return; /* This matches the pushlevel in begin_template_parm_list. */ finish_scope (); --processing_template_decl; current_template_parms = TREE_CHAIN (current_template_parms); } /* Within the declaration of a template, return all levels of template parameters that apply. The template parameters are represented as a TREE_VEC, in the form documented in cp-tree.h for template arguments. */ static tree current_template_args (void) { tree header; tree args = NULL_TREE; int length = TMPL_PARMS_DEPTH (current_template_parms); int l = length; /* If there is only one level of template parameters, we do not create a TREE_VEC of TREE_VECs. Instead, we return a single TREE_VEC containing the arguments. */ if (length > 1) args = make_tree_vec (length); for (header = current_template_parms; header; header = TREE_CHAIN (header)) { tree a = copy_node (TREE_VALUE (header)); int i; TREE_TYPE (a) = NULL_TREE; for (i = TREE_VEC_LENGTH (a) - 1; i >= 0; --i) { tree t = TREE_VEC_ELT (a, i); /* T will be a list if we are called from within a begin/end_template_parm_list pair, but a vector directly if within a begin/end_member_template_processing pair. */ if (TREE_CODE (t) == TREE_LIST) { t = TREE_VALUE (t); if (!error_operand_p (t)) { if (TREE_CODE (t) == TYPE_DECL || TREE_CODE (t) == TEMPLATE_DECL) { t = TREE_TYPE (t); if (TEMPLATE_TYPE_PARAMETER_PACK (t)) { /* Turn this argument into a TYPE_ARGUMENT_PACK with a single element, which expands T. */ tree vec = make_tree_vec (1); #ifdef ENABLE_CHECKING SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (vec, TREE_VEC_LENGTH (vec)); #endif TREE_VEC_ELT (vec, 0) = make_pack_expansion (t); t = cxx_make_type (TYPE_ARGUMENT_PACK); SET_ARGUMENT_PACK_ARGS (t, vec); } } else { t = DECL_INITIAL (t); if (TEMPLATE_PARM_PARAMETER_PACK (t)) { /* Turn this argument into a NONTYPE_ARGUMENT_PACK with a single element, which expands T. */ tree vec = make_tree_vec (1); tree type = TREE_TYPE (TEMPLATE_PARM_DECL (t)); #ifdef ENABLE_CHECKING SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (vec, TREE_VEC_LENGTH (vec)); #endif TREE_VEC_ELT (vec, 0) = make_pack_expansion (t); t = make_node (NONTYPE_ARGUMENT_PACK); SET_ARGUMENT_PACK_ARGS (t, vec); TREE_TYPE (t) = type; } } TREE_VEC_ELT (a, i) = t; } } } #ifdef ENABLE_CHECKING SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (a, TREE_VEC_LENGTH (a)); #endif if (length > 1) TREE_VEC_ELT (args, --l) = a; else args = a; } return args; } /* Update the declared TYPE by doing any lookups which were thought to be dependent, but are not now that we know the SCOPE of the declarator. */ tree maybe_update_decl_type (tree orig_type, tree scope) { tree type = orig_type; if (type == NULL_TREE) return type; if (TREE_CODE (orig_type) == TYPE_DECL) type = TREE_TYPE (type); if (scope && TYPE_P (scope) && dependent_type_p (scope) && dependent_type_p (type) /* Don't bother building up the args in this case. */ && TREE_CODE (type) != TEMPLATE_TYPE_PARM) { /* tsubst in the args corresponding to the template parameters, including auto if present. Most things will be unchanged, but make_typename_type and tsubst_qualified_id will resolve TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */ tree args = current_template_args (); tree auto_node = type_uses_auto (type); tree pushed; if (auto_node) { tree auto_vec = make_tree_vec (1); TREE_VEC_ELT (auto_vec, 0) = auto_node; args = add_to_template_args (args, auto_vec); } pushed = push_scope (scope); type = tsubst (type, args, tf_warning_or_error, NULL_TREE); if (pushed) pop_scope (scope); } if (type == error_mark_node) return orig_type; if (TREE_CODE (orig_type) == TYPE_DECL) { if (same_type_p (type, TREE_TYPE (orig_type))) type = orig_type; else type = TYPE_NAME (type); } return type; } /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated template PARMS. If MEMBER_TEMPLATE_P is true, the new template is a member template. Used by push_template_decl below. */ static tree build_template_decl (tree decl, tree parms, bool member_template_p) { tree tmpl = build_lang_decl (TEMPLATE_DECL, DECL_NAME (decl), NULL_TREE); DECL_TEMPLATE_PARMS (tmpl) = parms; DECL_CONTEXT (tmpl) = DECL_CONTEXT (decl); DECL_MEMBER_TEMPLATE_P (tmpl) = member_template_p; return tmpl; } struct template_parm_data { /* The level of the template parameters we are currently processing. */ int level; /* The index of the specialization argument we are currently processing. */ int current_arg; /* An array whose size is the number of template parameters. The elements are nonzero if the parameter has been used in any one of the arguments processed so far. */ int* parms; /* An array whose size is the number of template arguments. The elements are nonzero if the argument makes use of template parameters of this level. */ int* arg_uses_template_parms; }; /* Subroutine of push_template_decl used to see if each template parameter in a partial specialization is used in the explicit argument list. If T is of the LEVEL given in DATA (which is treated as a template_parm_data*), then DATA->PARMS is marked appropriately. */ static int mark_template_parm (tree t, void* data) { int level; int idx; struct template_parm_data* tpd = (struct template_parm_data*) data; if (TREE_CODE (t) == TEMPLATE_PARM_INDEX) { level = TEMPLATE_PARM_LEVEL (t); idx = TEMPLATE_PARM_IDX (t); } else { level = TEMPLATE_TYPE_LEVEL (t); idx = TEMPLATE_TYPE_IDX (t); } if (level == tpd->level) { tpd->parms[idx] = 1; tpd->arg_uses_template_parms[tpd->current_arg] = 1; } /* Return zero so that for_each_template_parm will continue the traversal of the tree; we want to mark *every* template parm. */ return 0; } /* Process the partial specialization DECL. */ static tree process_partial_specialization (tree decl) { tree type = TREE_TYPE (decl); tree maintmpl = CLASSTYPE_TI_TEMPLATE (type); tree specargs = CLASSTYPE_TI_ARGS (type); tree inner_args = INNERMOST_TEMPLATE_ARGS (specargs); tree main_inner_parms = DECL_INNERMOST_TEMPLATE_PARMS (maintmpl); tree inner_parms; int nargs = TREE_VEC_LENGTH (inner_args); int ntparms; int i; int did_error_intro = 0; struct template_parm_data tpd; struct template_parm_data tpd2; gcc_assert (current_template_parms); inner_parms = INNERMOST_TEMPLATE_PARMS (current_template_parms); ntparms = TREE_VEC_LENGTH (inner_parms); /* We check that each of the template parameters given in the partial specialization is used in the argument list to the specialization. For example: template <class T> struct S; template <class T> struct S<T*>; The second declaration is OK because `T*' uses the template parameter T, whereas template <class T> struct S<int>; is no good. Even trickier is: template <class T> struct S1 { template <class U> struct S2; template <class U> struct S2<T>; }; The S2<T> declaration is actually invalid; it is a full-specialization. Of course, template <class U> struct S2<T (*)(U)>; or some such would have been OK. */ tpd.level = TMPL_PARMS_DEPTH (current_template_parms); tpd.parms = (int *) alloca (sizeof (int) * ntparms); memset (tpd.parms, 0, sizeof (int) * ntparms); tpd.arg_uses_template_parms = (int *) alloca (sizeof (int) * nargs); memset (tpd.arg_uses_template_parms, 0, sizeof (int) * nargs); for (i = 0; i < nargs; ++i) { tpd.current_arg = i; for_each_template_parm (TREE_VEC_ELT (inner_args, i), &mark_template_parm, &tpd, NULL, /*include_nondeduced_p=*/false); } for (i = 0; i < ntparms; ++i) if (tpd.parms[i] == 0) { /* One of the template parms was not used in the specialization. */ if (!did_error_intro) { error ("template parameters not used in partial specialization:"); did_error_intro = 1; } error (" %qD", TREE_VALUE (TREE_VEC_ELT (inner_parms, i))); } /* [temp.class.spec] The argument list of the specialization shall not be identical to the implicit argument list of the primary template. */ if (comp_template_args (inner_args, INNERMOST_TEMPLATE_ARGS (CLASSTYPE_TI_ARGS (TREE_TYPE (maintmpl))))) error ("partial specialization %qT does not specialize any template arguments", type); /* [temp.class.spec] A partially specialized non-type argument expression shall not involve template parameters of the partial specialization except when the argument expression is a simple identifier. The type of a template parameter corresponding to a specialized non-type argument shall not be dependent on a parameter of the specialization. Also, we verify that pack expansions only occur at the end of the argument list. */ gcc_assert (nargs == DECL_NTPARMS (maintmpl)); tpd2.parms = 0; for (i = 0; i < nargs; ++i) { tree parm = TREE_VALUE (TREE_VEC_ELT (main_inner_parms, i)); tree arg = TREE_VEC_ELT (inner_args, i); tree packed_args = NULL_TREE; int j, len = 1; if (ARGUMENT_PACK_P (arg)) { /* Extract the arguments from the argument pack. We'll be iterating over these in the following loop. */ packed_args = ARGUMENT_PACK_ARGS (arg); len = TREE_VEC_LENGTH (packed_args); } for (j = 0; j < len; j++) { if (packed_args) /* Get the Jth argument in the parameter pack. */ arg = TREE_VEC_ELT (packed_args, j); if (PACK_EXPANSION_P (arg)) { /* Pack expansions must come at the end of the argument list. */ if ((packed_args && j < len - 1) || (!packed_args && i < nargs - 1)) { if (TREE_CODE (arg) == EXPR_PACK_EXPANSION) error ("parameter pack argument %qE must be at the " "end of the template argument list", arg); else error ("parameter pack argument %qT must be at the " "end of the template argument list", arg); } } if (TREE_CODE (arg) == EXPR_PACK_EXPANSION) /* We only care about the pattern. */ arg = PACK_EXPANSION_PATTERN (arg); if (/* These first two lines are the `non-type' bit. */ !TYPE_P (arg) && TREE_CODE (arg) != TEMPLATE_DECL /* This next line is the `argument expression is not just a simple identifier' condition and also the `specialized non-type argument' bit. */ && TREE_CODE (arg) != TEMPLATE_PARM_INDEX) { if ((!packed_args && tpd.arg_uses_template_parms[i]) || (packed_args && uses_template_parms (arg))) error ("template argument %qE involves template parameter(s)", arg); else { /* Look at the corresponding template parameter, marking which template parameters its type depends upon. */ tree type = TREE_TYPE (parm); if (!tpd2.parms) { /* We haven't yet initialized TPD2. Do so now. */ tpd2.arg_uses_template_parms = (int *) alloca (sizeof (int) * nargs); /* The number of parameters here is the number in the main template, which, as checked in the assertion above, is NARGS. */ tpd2.parms = (int *) alloca (sizeof (int) * nargs); tpd2.level = TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (maintmpl)); } /* Mark the template parameters. But this time, we're looking for the template parameters of the main template, not in the specialization. */ tpd2.current_arg = i; tpd2.arg_uses_template_parms[i] = 0; memset (tpd2.parms, 0, sizeof (int) * nargs); for_each_template_parm (type, &mark_template_parm, &tpd2, NULL, /*include_nondeduced_p=*/false); if (tpd2.arg_uses_template_parms [i]) { /* The type depended on some template parameters. If they are fully specialized in the specialization, that's OK. */ int j; int count = 0; for (j = 0; j < nargs; ++j) if (tpd2.parms[j] != 0 && tpd.arg_uses_template_parms [j]) ++count; if (count != 0) error_n (input_location, count, "type %qT of template argument %qE depends " "on a template parameter", "type %qT of template argument %qE depends " "on template parameters", type, arg); } } } } } /* We should only get here once. */ gcc_assert (!COMPLETE_TYPE_P (type)); DECL_TEMPLATE_SPECIALIZATIONS (maintmpl) = tree_cons (specargs, inner_parms, DECL_TEMPLATE_SPECIALIZATIONS (maintmpl)); TREE_TYPE (DECL_TEMPLATE_SPECIALIZATIONS (maintmpl)) = type; return decl; } /* Check that a template declaration's use of default arguments and parameter packs is not invalid. Here, PARMS are the template parameters. IS_PRIMARY is nonzero if DECL is the thing declared by a primary template. IS_PARTIAL is nonzero if DECL is a partial specialization. IS_FRIEND_DECL is nonzero if DECL is a friend function template declaration (but not a definition); 1 indicates a declaration, 2 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are emitted for extraneous default arguments. Returns TRUE if there were no errors found, FALSE otherwise. */ bool check_default_tmpl_args (tree decl, tree parms, int is_primary, int is_partial, int is_friend_decl) { const char *msg; int last_level_to_check; tree parm_level; bool no_errors = true; /* [temp.param] A default template-argument shall not be specified in a function template declaration or a function template definition, nor in the template-parameter-list of the definition of a member of a class template. */ if (TREE_CODE (CP_DECL_CONTEXT (decl)) == FUNCTION_DECL) /* You can't have a function template declaration in a local scope, nor you can you define a member of a class template in a local scope. */ return true; if (current_class_type && !TYPE_BEING_DEFINED (current_class_type) && DECL_LANG_SPECIFIC (decl) && DECL_DECLARES_FUNCTION_P (decl) /* If this is either a friend defined in the scope of the class or a member function. */ && (DECL_FUNCTION_MEMBER_P (decl) ? same_type_p (DECL_CONTEXT (decl), current_class_type) : DECL_FRIEND_CONTEXT (decl) ? same_type_p (DECL_FRIEND_CONTEXT (decl), current_class_type) : false) /* And, if it was a member function, it really was defined in the scope of the class. */ && (!DECL_FUNCTION_MEMBER_P (decl) || DECL_INITIALIZED_IN_CLASS_P (decl))) /* We already checked these parameters when the template was declared, so there's no need to do it again now. This function was defined in class scope, but we're processing it's body now that the class is complete. */ return true; /* Core issue 226 (C++0x only): the following only applies to class templates. */ if ((cxx_dialect == cxx98) || TREE_CODE (decl) != FUNCTION_DECL) { /* [temp.param] If a template-parameter has a default template-argument, all subsequent template-parameters shall have a default template-argument supplied. */ for (parm_level = parms; parm_level; parm_level = TREE_CHAIN (parm_level)) { tree inner_parms = TREE_VALUE (parm_level); int ntparms = TREE_VEC_LENGTH (inner_parms); int seen_def_arg_p = 0; int i; for (i = 0; i < ntparms; ++i) { tree parm = TREE_VEC_ELT (inner_parms, i); if (parm == error_mark_node) continue; if (TREE_PURPOSE (parm)) seen_def_arg_p = 1; else if (seen_def_arg_p && !template_parameter_pack_p (TREE_VALUE (parm))) { error ("no default argument for %qD", TREE_VALUE (parm)); /* For better subsequent error-recovery, we indicate that there should have been a default argument. */ TREE_PURPOSE (parm) = error_mark_node; no_errors = false; } else if (is_primary && !is_partial && !is_friend_decl /* Don't complain about an enclosing partial specialization. */ && parm_level == parms && TREE_CODE (decl) == TYPE_DECL && i < ntparms - 1 && template_parameter_pack_p (TREE_VALUE (parm))) { /* A primary class template can only have one parameter pack, at the end of the template parameter list. */ if (TREE_CODE (TREE_VALUE (parm)) == PARM_DECL) error ("parameter pack %qE must be at the end of the" " template parameter list", TREE_VALUE (parm)); else error ("parameter pack %qT must be at the end of the" " template parameter list", TREE_TYPE (TREE_VALUE (parm))); TREE_VALUE (TREE_VEC_ELT (inner_parms, i)) = error_mark_node; no_errors = false; } } } } if (((cxx_dialect == cxx98) && TREE_CODE (decl) != TYPE_DECL) || is_partial || !is_primary || is_friend_decl) /* For an ordinary class template, default template arguments are allowed at the innermost level, e.g.: template <class T = int> struct S {}; but, in a partial specialization, they're not allowed even there, as we have in [temp.class.spec]: The template parameter list of a specialization shall not contain default template argument values. So, for a partial specialization, or for a function template (in C++98/C++03), we look at all of them. */ ; else /* But, for a primary class template that is not a partial specialization we look at all template parameters except the innermost ones. */ parms = TREE_CHAIN (parms); /* Figure out what error message to issue. */ if (is_friend_decl == 2) msg = G_("default template arguments may not be used in function template " "friend re-declaration"); else if (is_friend_decl) msg = G_("default template arguments may not be used in function template " "friend declarations"); else if (TREE_CODE (decl) == FUNCTION_DECL && (cxx_dialect == cxx98)) msg = G_("default template arguments may not be used in function templates " "without -std=c++0x or -std=gnu++0x"); else if (is_partial) msg = G_("default template arguments may not be used in " "partial specializations"); else msg = G_("default argument for template parameter for class enclosing %qD"); if (current_class_type && TYPE_BEING_DEFINED (current_class_type)) /* If we're inside a class definition, there's no need to examine the parameters to the class itself. On the one hand, they will be checked when the class is defined, and, on the other, default arguments are valid in things like: template <class T = double> struct S { template <class U> void f(U); }; Here the default argument for `S' has no bearing on the declaration of `f'. */ last_level_to_check = template_class_depth (current_class_type) + 1; else /* Check everything. */ last_level_to_check = 0; for (parm_level = parms; parm_level && TMPL_PARMS_DEPTH (parm_level) >= last_level_to_check; parm_level = TREE_CHAIN (parm_level)) { tree inner_parms = TREE_VALUE (parm_level); int i; int ntparms; ntparms = TREE_VEC_LENGTH (inner_parms); for (i = 0; i < ntparms; ++i) { if (TREE_VEC_ELT (inner_parms, i) == error_mark_node) continue; if (TREE_PURPOSE (TREE_VEC_ELT (inner_parms, i))) { if (msg) { no_errors = false; if (is_friend_decl == 2) return no_errors; error (msg, decl); msg = 0; } /* Clear out the default argument so that we are not confused later. */ TREE_PURPOSE (TREE_VEC_ELT (inner_parms, i)) = NULL_TREE; } } /* At this point, if we're still interested in issuing messages, they must apply to classes surrounding the object declared. */ if (msg) msg = G_("default argument for template parameter for class " "enclosing %qD"); } return no_errors; } /* Worker for push_template_decl_real, called via for_each_template_parm. DATA is really an int, indicating the level of the parameters we are interested in. If T is a template parameter of that level, return nonzero. */ static int template_parm_this_level_p (tree t, void* data) { int this_level = *(int *)data; int level; if (TREE_CODE (t) == TEMPLATE_PARM_INDEX) level = TEMPLATE_PARM_LEVEL (t); else level = TEMPLATE_TYPE_LEVEL (t); return level == this_level; } /* Creates a TEMPLATE_DECL for the indicated DECL using the template parameters given by current_template_args, or reuses a previously existing one, if appropriate. Returns the DECL, or an equivalent one, if it is replaced via a call to duplicate_decls. If IS_FRIEND is true, DECL is a friend declaration. */ tree push_template_decl_real (tree decl, bool is_friend) { tree tmpl; tree args; tree info; tree ctx; int primary; int is_partial; int new_template_p = 0; /* True if the template is a member template, in the sense of [temp.mem]. */ bool member_template_p = false; if (decl == error_mark_node || !current_template_parms) return error_mark_node; /* See if this is a partial specialization. */ is_partial = (DECL_IMPLICIT_TYPEDEF_P (decl) && TREE_CODE (TREE_TYPE (decl)) != ENUMERAL_TYPE && CLASSTYPE_TEMPLATE_SPECIALIZATION (TREE_TYPE (decl))); if (TREE_CODE (decl) == FUNCTION_DECL && DECL_FRIEND_P (decl)) is_friend = true; if (is_friend) /* For a friend, we want the context of the friend function, not the type of which it is a friend. */ ctx = DECL_CONTEXT (decl); else if (CP_DECL_CONTEXT (decl) && TREE_CODE (CP_DECL_CONTEXT (decl)) != NAMESPACE_DECL) /* In the case of a virtual function, we want the class in which it is defined. */ ctx = CP_DECL_CONTEXT (decl); else /* Otherwise, if we're currently defining some class, the DECL is assumed to be a member of the class. */ ctx = current_scope (); if (ctx && TREE_CODE (ctx) == NAMESPACE_DECL) ctx = NULL_TREE; if (!DECL_CONTEXT (decl)) DECL_CONTEXT (decl) = FROB_CONTEXT (current_namespace); /* See if this is a primary template. */ if (is_friend && ctx) /* A friend template that specifies a class context, i.e. template <typename T> friend void A<T>::f(); is not primary. */ primary = 0; else primary = template_parm_scope_p (); if (primary) { if (DECL_CLASS_SCOPE_P (decl)) member_template_p = true; if (TREE_CODE (decl) == TYPE_DECL && ANON_AGGRNAME_P (DECL_NAME (decl))) { error ("template class without a name"); return error_mark_node; } else if (TREE_CODE (decl) == FUNCTION_DECL) { if (DECL_DESTRUCTOR_P (decl)) { /* [temp.mem] A destructor shall not be a member template. */ error ("destructor %qD declared as member template", decl); return error_mark_node; } if (NEW_DELETE_OPNAME_P (DECL_NAME (decl)) && (!TYPE_ARG_TYPES (TREE_TYPE (decl)) || TYPE_ARG_TYPES (TREE_TYPE (decl)) == void_list_node || !TREE_CHAIN (TYPE_ARG_TYPES (TREE_TYPE (decl))) || (TREE_CHAIN (TYPE_ARG_TYPES ((TREE_TYPE (decl)))) == void_list_node))) { /* [basic.stc.dynamic.allocation] An allocation function can be a function template. ... Template allocation functions shall have two or more parameters. */ error ("invalid template declaration of %qD", decl); return error_mark_node; } } else if (DECL_IMPLICIT_TYPEDEF_P (decl) && CLASS_TYPE_P (TREE_TYPE (decl))) /* OK */; else { error ("template declaration of %q#D", decl); return error_mark_node; } } /* Check to see that the rules regarding the use of default arguments are not being violated. */ check_default_tmpl_args (decl, current_template_parms, primary, is_partial, /*is_friend_decl=*/0); /* Ensure that there are no parameter packs in the type of this declaration that have not been expanded. */ if (TREE_CODE (decl) == FUNCTION_DECL) { /* Check each of the arguments individually to see if there are any bare parameter packs. */ tree type = TREE_TYPE (decl); tree arg = DECL_ARGUMENTS (decl); tree argtype = TYPE_ARG_TYPES (type); while (arg && argtype) { if (!FUNCTION_PARAMETER_PACK_P (arg) && check_for_bare_parameter_packs (TREE_TYPE (arg))) { /* This is a PARM_DECL that contains unexpanded parameter packs. We have already complained about this in the check_for_bare_parameter_packs call, so just replace these types with ERROR_MARK_NODE. */ TREE_TYPE (arg) = error_mark_node; TREE_VALUE (argtype) = error_mark_node; } arg = TREE_CHAIN (arg); argtype = TREE_CHAIN (argtype); } /* Check for bare parameter packs in the return type and the exception specifiers. */ if (check_for_bare_parameter_packs (TREE_TYPE (type))) /* Errors were already issued, set return type to int as the frontend doesn't expect error_mark_node as the return type. */ TREE_TYPE (type) = integer_type_node; if (check_for_bare_parameter_packs (TYPE_RAISES_EXCEPTIONS (type))) TYPE_RAISES_EXCEPTIONS (type) = NULL_TREE; } else if (check_for_bare_parameter_packs (TREE_TYPE (decl))) { TREE_TYPE (decl) = error_mark_node; return error_mark_node; } if (is_partial) return process_partial_specialization (decl); args = current_template_args (); if (!ctx || TREE_CODE (ctx) == FUNCTION_DECL || (CLASS_TYPE_P (ctx) && TYPE_BEING_DEFINED (ctx)) || (is_friend && !DECL_TEMPLATE_INFO (decl))) { if (DECL_LANG_SPECIFIC (decl) && DECL_TEMPLATE_INFO (decl) && DECL_TI_TEMPLATE (decl)) tmpl = DECL_TI_TEMPLATE (decl); /* If DECL is a TYPE_DECL for a class-template, then there won't be DECL_LANG_SPECIFIC. The information equivalent to DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */ else if (DECL_IMPLICIT_TYPEDEF_P (decl) && TYPE_TEMPLATE_INFO (TREE_TYPE (decl)) && TYPE_TI_TEMPLATE (TREE_TYPE (decl))) { /* Since a template declaration already existed for this class-type, we must be redeclaring it here. Make sure that the redeclaration is valid. */ redeclare_class_template (TREE_TYPE (decl), current_template_parms); /* We don't need to create a new TEMPLATE_DECL; just use the one we already had. */ tmpl = TYPE_TI_TEMPLATE (TREE_TYPE (decl)); } else { tmpl = build_template_decl (decl, current_template_parms, member_template_p); new_template_p = 1; if (DECL_LANG_SPECIFIC (decl) && DECL_TEMPLATE_SPECIALIZATION (decl)) { /* A specialization of a member template of a template class. */ SET_DECL_TEMPLATE_SPECIALIZATION (tmpl); DECL_TEMPLATE_INFO (tmpl) = DECL_TEMPLATE_INFO (decl); DECL_TEMPLATE_INFO (decl) = NULL_TREE; } } } else { tree a, t, current, parms; int i; tree tinfo = get_template_info (decl); if (!tinfo) { error ("template definition of non-template %q#D", decl); return error_mark_node; } tmpl = TI_TEMPLATE (tinfo); if (DECL_FUNCTION_TEMPLATE_P (tmpl) && DECL_TEMPLATE_INFO (decl) && DECL_TI_ARGS (decl) && DECL_TEMPLATE_SPECIALIZATION (decl) && DECL_MEMBER_TEMPLATE_P (tmpl)) { tree new_tmpl; /* The declaration is a specialization of a member template, declared outside the class. Therefore, the innermost template arguments will be NULL, so we replace them with the arguments determined by the earlier call to check_explicit_specialization. */ args = DECL_TI_ARGS (decl); new_tmpl = build_template_decl (decl, current_template_parms, member_template_p); DECL_TEMPLATE_RESULT (new_tmpl) = decl; TREE_TYPE (new_tmpl) = TREE_TYPE (decl); DECL_TI_TEMPLATE (decl) = new_tmpl; SET_DECL_TEMPLATE_SPECIALIZATION (new_tmpl); DECL_TEMPLATE_INFO (new_tmpl) = build_template_info (tmpl, args); register_specialization (new_tmpl, most_general_template (tmpl), args, is_friend, 0); return decl; } /* Make sure the template headers we got make sense. */ parms = DECL_TEMPLATE_PARMS (tmpl); i = TMPL_PARMS_DEPTH (parms); if (TMPL_ARGS_DEPTH (args) != i) { error ("expected %d levels of template parms for %q#D, got %d", i, decl, TMPL_ARGS_DEPTH (args)); } else for (current = decl; i > 0; --i, parms = TREE_CHAIN (parms)) { a = TMPL_ARGS_LEVEL (args, i); t = INNERMOST_TEMPLATE_PARMS (parms); if (TREE_VEC_LENGTH (t) != TREE_VEC_LENGTH (a)) { if (current == decl) error ("got %d template parameters for %q#D", TREE_VEC_LENGTH (a), decl); else error ("got %d template parameters for %q#T", TREE_VEC_LENGTH (a), current); error (" but %d required", TREE_VEC_LENGTH (t)); return error_mark_node; } if (current == decl) current = ctx; else if (current == NULL_TREE) /* Can happen in erroneous input. */ break; else current = (TYPE_P (current) ? TYPE_CONTEXT (current) : DECL_CONTEXT (current)); } /* Check that the parms are used in the appropriate qualifying scopes in the declarator. */ if (!comp_template_args (TI_ARGS (tinfo), TI_ARGS (get_template_info (DECL_TEMPLATE_RESULT (tmpl))))) { error ("\ template arguments to %qD do not match original template %qD", decl, DECL_TEMPLATE_RESULT (tmpl)); if (!uses_template_parms (TI_ARGS (tinfo))) inform (input_location, "use template<> for an explicit specialization"); /* Avoid crash in import_export_decl. */ DECL_INTERFACE_KNOWN (decl) = 1; return error_mark_node; } } DECL_TEMPLATE_RESULT (tmpl) = decl; TREE_TYPE (tmpl) = TREE_TYPE (decl); /* Push template declarations for global functions and types. Note that we do not try to push a global template friend declared in a template class; such a thing may well depend on the template parameters of the class. */ if (new_template_p && !ctx && !(is_friend && template_class_depth (current_class_type) > 0)) { tmpl = pushdecl_namespace_level (tmpl, is_friend); if (tmpl == error_mark_node) return error_mark_node; /* Hide template friend classes that haven't been declared yet. */ if (is_friend && TREE_CODE (decl) == TYPE_DECL) { DECL_ANTICIPATED (tmpl) = 1; DECL_FRIEND_P (tmpl) = 1; } } if (primary) { tree parms = DECL_TEMPLATE_PARMS (tmpl); int i; DECL_PRIMARY_TEMPLATE (tmpl) = tmpl; if (DECL_CONV_FN_P (tmpl)) { int depth = TMPL_PARMS_DEPTH (parms); /* It is a conversion operator. See if the type converted to depends on innermost template operands. */ if (uses_template_parms_level (TREE_TYPE (TREE_TYPE (tmpl)), depth)) DECL_TEMPLATE_CONV_FN_P (tmpl) = 1; } /* Give template template parms a DECL_CONTEXT of the template for which they are a parameter. */ parms = INNERMOST_TEMPLATE_PARMS (parms); for (i = TREE_VEC_LENGTH (parms) - 1; i >= 0; --i) { tree parm = TREE_VALUE (TREE_VEC_ELT (parms, i)); if (TREE_CODE (parm) == TEMPLATE_DECL) DECL_CONTEXT (parm) = tmpl; } } /* The DECL_TI_ARGS of DECL contains full set of arguments referring back to its most general template. If TMPL is a specialization, ARGS may only have the innermost set of arguments. Add the missing argument levels if necessary. */ if (DECL_TEMPLATE_INFO (tmpl)) args = add_outermost_template_args (DECL_TI_ARGS (tmpl), args); info = build_template_info (tmpl, args); if (DECL_IMPLICIT_TYPEDEF_P (decl)) SET_TYPE_TEMPLATE_INFO (TREE_TYPE (tmpl), info); else if (DECL_LANG_SPECIFIC (decl)) DECL_TEMPLATE_INFO (decl) = info; return DECL_TEMPLATE_RESULT (tmpl); } tree push_template_decl (tree decl) { return push_template_decl_real (decl, false); } /* Called when a class template TYPE is redeclared with the indicated template PARMS, e.g.: template <class T> struct S; template <class T> struct S {}; */ bool redeclare_class_template (tree type, tree parms) { tree tmpl; tree tmpl_parms; int i; if (!TYPE_TEMPLATE_INFO (type)) { error ("%qT is not a template type", type); return false; } tmpl = TYPE_TI_TEMPLATE (type); if (!PRIMARY_TEMPLATE_P (tmpl)) /* The type is nested in some template class. Nothing to worry about here; there are no new template parameters for the nested type. */ return true; if (!parms) { error ("template specifiers not specified in declaration of %qD", tmpl); return false; } parms = INNERMOST_TEMPLATE_PARMS (parms); tmpl_parms = DECL_INNERMOST_TEMPLATE_PARMS (tmpl); if (TREE_VEC_LENGTH (parms) != TREE_VEC_LENGTH (tmpl_parms)) { error_n (input_location, TREE_VEC_LENGTH (parms), "redeclared with %d template parameter", "redeclared with %d template parameters", TREE_VEC_LENGTH (parms)); inform_n (input_location, TREE_VEC_LENGTH (tmpl_parms), "previous declaration %q+D used %d template parameter", "previous declaration %q+D used %d template parameters", tmpl, TREE_VEC_LENGTH (tmpl_parms)); return false; } for (i = 0; i < TREE_VEC_LENGTH (tmpl_parms); ++i) { tree tmpl_parm; tree parm; tree tmpl_default; tree parm_default; if (TREE_VEC_ELT (tmpl_parms, i) == error_mark_node || TREE_VEC_ELT (parms, i) == error_mark_node) continue; tmpl_parm = TREE_VALUE (TREE_VEC_ELT (tmpl_parms, i)); if (tmpl_parm == error_mark_node) return false; parm = TREE_VALUE (TREE_VEC_ELT (parms, i)); tmpl_default = TREE_PURPOSE (TREE_VEC_ELT (tmpl_parms, i)); parm_default = TREE_PURPOSE (TREE_VEC_ELT (parms, i)); /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or TEMPLATE_DECL. */ if (TREE_CODE (tmpl_parm) != TREE_CODE (parm) || (TREE_CODE (tmpl_parm) != TYPE_DECL && !same_type_p (TREE_TYPE (tmpl_parm), TREE_TYPE (parm))) || (TREE_CODE (tmpl_parm) != PARM_DECL && (TEMPLATE_TYPE_PARAMETER_PACK (TREE_TYPE (tmpl_parm)) != TEMPLATE_TYPE_PARAMETER_PACK (TREE_TYPE (parm)))) || (TREE_CODE (tmpl_parm) == PARM_DECL && (TEMPLATE_PARM_PARAMETER_PACK (DECL_INITIAL (tmpl_parm)) != TEMPLATE_PARM_PARAMETER_PACK (DECL_INITIAL (parm))))) { error ("template parameter %q+#D", tmpl_parm); error ("redeclared here as %q#D", parm); return false; } if (tmpl_default != NULL_TREE && parm_default != NULL_TREE) { /* We have in [temp.param]: A template-parameter may not be given default arguments by two different declarations in the same scope. */ error_at (input_location, "redefinition of default argument for %q#D", parm); inform (DECL_SOURCE_LOCATION (tmpl_parm), "original definition appeared here"); return false; } if (parm_default != NULL_TREE) /* Update the previous template parameters (which are the ones that will really count) with the new default value. */ TREE_PURPOSE (TREE_VEC_ELT (tmpl_parms, i)) = parm_default; else if (tmpl_default != NULL_TREE) /* Update the new parameters, too; they'll be used as the parameters for any members. */ TREE_PURPOSE (TREE_VEC_ELT (parms, i)) = tmpl_default; } return true; } /* Simplify EXPR if it is a non-dependent expression. Returns the (possibly simplified) expression. */ tree fold_non_dependent_expr (tree expr) { if (expr == NULL_TREE) return NULL_TREE; /* If we're in a template, but EXPR isn't value dependent, simplify it. We're supposed to treat: template <typename T> void f(T[1 + 1]); template <typename T> void f(T[2]); as two declarations of the same function, for example. */ if (processing_template_decl && !type_dependent_expression_p (expr) && !value_dependent_expression_p (expr)) { HOST_WIDE_INT saved_processing_template_decl; saved_processing_template_decl = processing_template_decl; processing_template_decl = 0; expr = tsubst_copy_and_build (expr, /*args=*/NULL_TREE, tf_error, /*in_decl=*/NULL_TREE, /*function_p=*/false, /*integral_constant_expression_p=*/true); processing_template_decl = saved_processing_template_decl; } return expr; } /* EXPR is an expression which is used in a constant-expression context. For instance, it could be a VAR_DECL with a constant initializer. Extract the innermost constant expression. This is basically a more powerful version of integral_constant_value, which can be used also in templates where initializers can maintain a syntactic rather than semantic form (even if they are non-dependent, for access-checking purposes). */ static tree fold_decl_constant_value (tree expr) { tree const_expr = expr; do { expr = fold_non_dependent_expr (const_expr); const_expr = integral_constant_value (expr); } while (expr != const_expr); return expr; } /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which must be a function or a pointer-to-function type, as specified in [temp.arg.nontype]: disambiguate EXPR if it is an overload set, and check that the resulting function has external linkage. */ static tree convert_nontype_argument_function (tree type, tree expr) { tree fns = expr; tree fn, fn_no_ptr; fn = instantiate_type (type, fns, tf_none); if (fn == error_mark_node) return error_mark_node; fn_no_ptr = fn; if (TREE_CODE (fn_no_ptr) == ADDR_EXPR) fn_no_ptr = TREE_OPERAND (fn_no_ptr, 0); if (TREE_CODE (fn_no_ptr) == BASELINK) fn_no_ptr = BASELINK_FUNCTIONS (fn_no_ptr); /* [temp.arg.nontype]/1 A template-argument for a non-type, non-template template-parameter shall be one of: [...] -- the address of an object or function with external linkage. */ if (!DECL_EXTERNAL_LINKAGE_P (fn_no_ptr)) { error ("%qE is not a valid template argument for type %qT " "because function %qD has not external linkage", expr, type, fn_no_ptr); return NULL_TREE; } return fn; } /* Subroutine of convert_nontype_argument. Check if EXPR of type TYPE is a valid pointer-to-member constant. Emit an error otherwise. */ static bool check_valid_ptrmem_cst_expr (tree type, tree expr) { STRIP_NOPS (expr); if (expr && (null_ptr_cst_p (expr) || TREE_CODE (expr) == PTRMEM_CST)) return true; error ("%qE is not a valid template argument for type %qT", expr, type); error ("it must be a pointer-to-member of the form `&X::Y'"); return false; } /* Returns TRUE iff the address of OP is value-dependent. 14.6.2.4 [temp.dep.temp]: A non-integral non-type template-argument is dependent if its type is dependent or it has either of the following forms qualified-id & qualified-id and contains a nested-name-specifier which specifies a class-name that names a dependent type. We generalize this to just say that the address of a member of a dependent class is value-dependent; the above doesn't cover the address of a static data member named with an unqualified-id. */ static bool has_value_dependent_address (tree op) { /* We could use get_inner_reference here, but there's no need; this is only relevant for template non-type arguments, which can only be expressed as &id-expression. */ if (DECL_P (op)) { tree ctx = CP_DECL_CONTEXT (op); if (TYPE_P (ctx) && dependent_type_p (ctx)) return true; } return false; } /* Attempt to convert the non-type template parameter EXPR to the indicated TYPE. If the conversion is successful, return the converted value. If the conversion is unsuccessful, return NULL_TREE if we issued an error message, or error_mark_node if we did not. We issue error messages for out-and-out bad template parameters, but not simply because the conversion failed, since we might be just trying to do argument deduction. Both TYPE and EXPR must be non-dependent. The conversion follows the special rules described in [temp.arg.nontype], and it is much more strict than an implicit conversion. This function is called twice for each template argument (see lookup_template_class for a more accurate description of this problem). This means that we need to handle expressions which are not valid in a C++ source, but can be created from the first call (for instance, casts to perform conversions). These hacks can go away after we fix the double coercion problem. */ static tree convert_nontype_argument (tree type, tree expr) { tree expr_type; /* Detect immediately string literals as invalid non-type argument. This special-case is not needed for correctness (we would easily catch this later), but only to provide better diagnostic for this common user mistake. As suggested by DR 100, we do not mention linkage issues in the diagnostic as this is not the point. */ if (TREE_CODE (expr) == STRING_CST) { error ("%qE is not a valid template argument for type %qT " "because string literals can never be used in this context", expr, type); return NULL_TREE; } /* Add the ADDR_EXPR now for the benefit of value_dependent_expression_p. */ if (TYPE_PTROBV_P (type)) expr = decay_conversion (expr); /* If we are in a template, EXPR may be non-dependent, but still have a syntactic, rather than semantic, form. For example, EXPR might be a SCOPE_REF, rather than the VAR_DECL to which the SCOPE_REF refers. Preserving the qualifying scope is necessary so that access checking can be performed when the template is instantiated -- but here we need the resolved form so that we can convert the argument. */ if (TYPE_REF_OBJ_P (type) && has_value_dependent_address (expr)) /* If we want the address and it's value-dependent, don't fold. */; else expr = fold_non_dependent_expr (expr); if (error_operand_p (expr)) return error_mark_node; expr_type = TREE_TYPE (expr); /* HACK: Due to double coercion, we can get a NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here, which is the tree that we built on the first call (see below when coercing to reference to object or to reference to function). We just strip everything and get to the arg. See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C for examples. */ if (TREE_CODE (expr) == NOP_EXPR) { if (TYPE_REF_OBJ_P (type) || TYPE_REFFN_P (type)) { /* ??? Maybe we could use convert_from_reference here, but we would need to relax its constraints because the NOP_EXPR could actually change the type to something more cv-qualified, and this is not folded by convert_from_reference. */ tree addr = TREE_OPERAND (expr, 0); gcc_assert (TREE_CODE (expr_type) == REFERENCE_TYPE); gcc_assert (TREE_CODE (addr) == ADDR_EXPR); gcc_assert (TREE_CODE (TREE_TYPE (addr)) == POINTER_TYPE); gcc_assert (same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (expr_type), TREE_TYPE (TREE_TYPE (addr)))); expr = TREE_OPERAND (addr, 0); expr_type = TREE_TYPE (expr); } /* We could also generate a NOP_EXPR(ADDR_EXPR()) when the parameter is a pointer to object, through decay and qualification conversion. Let's strip everything. */ else if (TYPE_PTROBV_P (type)) { STRIP_NOPS (expr); gcc_assert (TREE_CODE (expr) == ADDR_EXPR); gcc_assert (TREE_CODE (TREE_TYPE (expr)) == POINTER_TYPE); /* Skip the ADDR_EXPR only if it is part of the decay for an array. Otherwise, it is part of the original argument in the source code. */ if (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == ARRAY_TYPE) expr = TREE_OPERAND (expr, 0); expr_type = TREE_TYPE (expr); } } /* [temp.arg.nontype]/5, bullet 1 For a non-type template-parameter of integral or enumeration type, integral promotions (_conv.prom_) and integral conversions (_conv.integral_) are applied. */ if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) { if (!INTEGRAL_OR_ENUMERATION_TYPE_P (expr_type)) return error_mark_node; expr = fold_decl_constant_value (expr); /* Notice that there are constant expressions like '4 % 0' which do not fold into integer constants. */ if (TREE_CODE (expr) != INTEGER_CST) { error ("%qE is not a valid template argument for type %qT " "because it is a non-constant expression", expr, type); return NULL_TREE; } /* At this point, an implicit conversion does what we want, because we already know that the expression is of integral type. */ expr = ocp_convert (type, expr, CONV_IMPLICIT, LOOKUP_PROTECT); if (expr == error_mark_node) return error_mark_node; /* Conversion was allowed: fold it to a bare integer constant. */ expr = fold (expr); } /* [temp.arg.nontype]/5, bullet 2 For a non-type template-parameter of type pointer to object, qualification conversions (_conv.qual_) and the array-to-pointer conversion (_conv.array_) are applied. */ else if (TYPE_PTROBV_P (type)) { /* [temp.arg.nontype]/1 (TC1 version, DR 49): A template-argument for a non-type, non-template template-parameter shall be one of: [...] -- the name of a non-type template-parameter; -- the address of an object or function with external linkage, [...] expressed as "& id-expression" where the & is optional if the name refers to a function or array, or if the corresponding template-parameter is a reference. Here, we do not care about functions, as they are invalid anyway for a parameter of type pointer-to-object. */ if (DECL_P (expr) && DECL_TEMPLATE_PARM_P (expr)) /* Non-type template parameters are OK. */ ; else if (TREE_CODE (expr) != ADDR_EXPR && TREE_CODE (expr_type) != ARRAY_TYPE) { if (TREE_CODE (expr) == VAR_DECL) { error ("%qD is not a valid template argument " "because %qD is a variable, not the address of " "a variable", expr, expr); return NULL_TREE; } /* Other values, like integer constants, might be valid non-type arguments of some other type. */ return error_mark_node; } else { tree decl; decl = ((TREE_CODE (expr) == ADDR_EXPR) ? TREE_OPERAND (expr, 0) : expr); if (TREE_CODE (decl) != VAR_DECL) { error ("%qE is not a valid template argument of type %qT " "because %qE is not a variable", expr, type, decl); return NULL_TREE; } else if (!DECL_EXTERNAL_LINKAGE_P (decl)) { error ("%qE is not a valid template argument of type %qT " "because %qD does not have external linkage", expr, type, decl); return NULL_TREE; } } expr = decay_conversion (expr); if (expr == error_mark_node) return error_mark_node; expr = perform_qualification_conversions (type, expr); if (expr == error_mark_node) return error_mark_node; } /* [temp.arg.nontype]/5, bullet 3 For a non-type template-parameter of type reference to object, no conversions apply. The type referred to by the reference may be more cv-qualified than the (otherwise identical) type of the template-argument. The template-parameter is bound directly to the template-argument, which must be an lvalue. */ else if (TYPE_REF_OBJ_P (type)) { if (!same_type_ignoring_top_level_qualifiers_p (TREE_TYPE (type), expr_type)) return error_mark_node; if (!at_least_as_qualified_p (TREE_TYPE (type), expr_type)) { error ("%qE is not a valid template argument for type %qT " "because of conflicts in cv-qualification", expr, type); return NULL_TREE; } if (!real_lvalue_p (expr)) { error ("%qE is not a valid template argument for type %qT " "because it is not an lvalue", expr, type); return NULL_TREE; } /* [temp.arg.nontype]/1 A template-argument for a non-type, non-template template-parameter shall be one of: [...] -- the address of an object or function with external linkage. */ if (TREE_CODE (expr) == INDIRECT_REF && TYPE_REF_OBJ_P (TREE_TYPE (TREE_OPERAND (expr, 0)))) { expr = TREE_OPERAND (expr, 0); if (DECL_P (expr)) { error ("%q#D is not a valid template argument for type %qT " "because a reference variable does not have a constant " "address", expr, type); return NULL_TREE; } } if (!DECL_P (expr)) { error ("%qE is not a valid template argument for type %qT " "because it is not an object with external linkage", expr, type); return NULL_TREE; } if (!DECL_EXTERNAL_LINKAGE_P (expr)) { error ("%qE is not a valid template argument for type %qT " "because object %qD has not external linkage", expr, type, expr); return NULL_TREE; } expr = build_nop (type, build_address (expr)); } /* [temp.arg.nontype]/5, bullet 4 For a non-type template-parameter of type pointer to function, only the function-to-pointer conversion (_conv.func_) is applied. If the template-argument represents a set of overloaded functions (or a pointer to such), the matching function is selected from the set (_over.over_). */ else if (TYPE_PTRFN_P (type)) { /* If the argument is a template-id, we might not have enough context information to decay the pointer. */ if (!type_unknown_p (expr_type)) { expr = decay_conversion (expr); if (expr == error_mark_node) return error_mark_node; } expr = convert_nontype_argument_function (type, expr); if (!expr || expr == error_mark_node) return expr; if (TREE_CODE (expr) != ADDR_EXPR) { error ("%qE is not a valid template argument for type %qT", expr, type); error ("it must be the address of a function with external linkage"); return NULL_TREE; } } /* [temp.arg.nontype]/5, bullet 5 For a non-type template-parameter of type reference to function, no conversions apply. If the template-argument represents a set of overloaded functions, the matching function is selected from the set (_over.over_). */ else if (TYPE_REFFN_P (type)) { if (TREE_CODE (expr) == ADDR_EXPR) { error ("%qE is not a valid template argument for type %qT " "because it is a pointer", expr, type); inform (input_location, "try using %qE instead", TREE_OPERAND (expr, 0)); return NULL_TREE; } expr = convert_nontype_argument_function (TREE_TYPE (type), expr); if (!expr || expr == error_mark_node) return expr; expr = build_nop (type, build_address (expr)); } /* [temp.arg.nontype]/5, bullet 6 For a non-type template-parameter of type pointer to member function, no conversions apply. If the template-argument represents a set of overloaded member functions, the matching member function is selected from the set (_over.over_). */ else if (TYPE_PTRMEMFUNC_P (type)) { expr = instantiate_type (type, expr, tf_none); if (expr == error_mark_node) return error_mark_node; /* [temp.arg.nontype] bullet 1 says the pointer to member expression must be a pointer-to-member constant. */ if (!check_valid_ptrmem_cst_expr (type, expr)) return error_mark_node; /* There is no way to disable standard conversions in resolve_address_of_overloaded_function (called by instantiate_type). It is possible that the call succeeded by converting &B::I to &D::I (where B is a base of D), so we need to reject this conversion here. Actually, even if there was a way to disable standard conversions, it would still be better to reject them here so that we can provide a superior diagnostic. */ if (!same_type_p (TREE_TYPE (expr), type)) { error ("%qE is not a valid template argument for type %qT " "because it is of type %qT", expr, type, TREE_TYPE (expr)); /* If we are just one standard conversion off, explain. */ if (can_convert (type, TREE_TYPE (expr))) inform (input_location, "standard conversions are not allowed in this context"); return NULL_TREE; } } /* [temp.arg.nontype]/5, bullet 7 For a non-type template-parameter of type pointer to data member, qualification conversions (_conv.qual_) are applied. */ else if (TYPE_PTRMEM_P (type)) { /* [temp.arg.nontype] bullet 1 says the pointer to member expression must be a pointer-to-member constant. */ if (!check_valid_ptrmem_cst_expr (type, expr)) return error_mark_node; expr = perform_qualification_conversions (type, expr); if (expr == error_mark_node) return expr; } /* A template non-type parameter must be one of the above. */ else gcc_unreachable (); /* Sanity check: did we actually convert the argument to the right type? */ gcc_assert (same_type_p (type, TREE_TYPE (expr))); return expr; } /* Subroutine of coerce_template_template_parms, which returns 1 if PARM_PARM and ARG_PARM match using the rule for the template parameters of template template parameters. Both PARM and ARG are template parameters; the rest of the arguments are the same as for coerce_template_template_parms. */ static int coerce_template_template_parm (tree parm, tree arg, tsubst_flags_t complain, tree in_decl, tree outer_args) { if (arg == NULL_TREE || arg == error_mark_node || parm == NULL_TREE || parm == error_mark_node) return 0; if (TREE_CODE (arg) != TREE_CODE (parm)) return 0; switch (TREE_CODE (parm)) { case TEMPLATE_DECL: /* We encounter instantiations of templates like template <template <template <class> class> class TT> class C; */ { tree parmparm = DECL_INNERMOST_TEMPLATE_PARMS (parm); tree argparm = DECL_INNERMOST_TEMPLATE_PARMS (arg); if (!coerce_template_template_parms (parmparm, argparm, complain, in_decl, outer_args)) return 0; } /* Fall through. */ case TYPE_DECL: if (TEMPLATE_TYPE_PARAMETER_PACK (TREE_TYPE (arg)) && !TEMPLATE_TYPE_PARAMETER_PACK (TREE_TYPE (parm))) /* Argument is a parameter pack but parameter is not. */ return 0; break; case PARM_DECL: /* The tsubst call is used to handle cases such as template <int> class C {}; template <class T, template <T> class TT> class D {}; D<int, C> d; i.e. the parameter list of TT depends on earlier parameters. */ if (!uses_template_parms (TREE_TYPE (arg)) && !same_type_p (tsubst (TREE_TYPE (parm), outer_args, complain, in_decl), TREE_TYPE (arg))) return 0; if (TEMPLATE_PARM_PARAMETER_PACK (DECL_INITIAL (arg)) && !TEMPLATE_PARM_PARAMETER_PACK (DECL_INITIAL (parm))) /* Argument is a parameter pack but parameter is not. */ return 0; break; default: gcc_unreachable (); } return 1; } /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for template template parameters. Both PARM_PARMS and ARG_PARMS are vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL or PARM_DECL. Consider the example: template <class T> class A; template<template <class U> class TT> class B; For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are the parameters to A, and OUTER_ARGS contains A. */ static int coerce_template_template_parms (tree parm_parms, tree arg_parms, tsubst_flags_t complain, tree in_decl, tree outer_args) { int nparms, nargs, i; tree parm, arg; int variadic_p = 0; gcc_assert (TREE_CODE (parm_parms) == TREE_VEC); gcc_assert (TREE_CODE (arg_parms) == TREE_VEC); nparms = TREE_VEC_LENGTH (parm_parms); nargs = TREE_VEC_LENGTH (arg_parms); /* Determine whether we have a parameter pack at the end of the template template parameter's template parameter list. */ if (TREE_VEC_ELT (parm_parms, nparms - 1) != error_mark_node) { parm = TREE_VALUE (TREE_VEC_ELT (parm_parms, nparms - 1)); if (parm == error_mark_node) return 0; switch (TREE_CODE (parm)) { case TEMPLATE_DECL: case TYPE_DECL: if (TEMPLATE_TYPE_PARAMETER_PACK (TREE_TYPE (parm))) variadic_p = 1; break; case PARM_DECL: if (TEMPLATE_PARM_PARAMETER_PACK (DECL_INITIAL (parm))) variadic_p = 1; break; default: gcc_unreachable (); } } if (nargs != nparms && !(variadic_p && nargs >= nparms - 1)) return 0; /* Check all of the template parameters except the parameter pack at the end (if any). */ for (i = 0; i < nparms - variadic_p; ++i) { if (TREE_VEC_ELT (parm_parms, i) == error_mark_node || TREE_VEC_ELT (arg_parms, i) == error_mark_node) continue; parm = TREE_VALUE (TREE_VEC_ELT (parm_parms, i)); arg = TREE_VALUE (TREE_VEC_ELT (arg_parms, i)); if (!coerce_template_template_parm (parm, arg, complain, in_decl, outer_args)) return 0; } if (variadic_p) { /* Check each of the template parameters in the template argument against the template parameter pack at the end of the template template parameter. */ if (TREE_VEC_ELT (parm_parms, i) == error_mark_node) return 0; parm = TREE_VALUE (TREE_VEC_ELT (parm_parms, i)); for (; i < nargs; ++i) { if (TREE_VEC_ELT (arg_parms, i) == error_mark_node) continue; arg = TREE_VALUE (TREE_VEC_ELT (arg_parms, i)); if (!coerce_template_template_parm (parm, arg, complain, in_decl, outer_args)) return 0; } } return 1; } /* Verifies that the deduced template arguments (in TARGS) for the template template parameters (in TPARMS) represent valid bindings, by comparing the template parameter list of each template argument to the template parameter list of its corresponding template template parameter, in accordance with DR150. This routine can only be called after all template arguments have been deduced. It will return TRUE if all of the template template parameter bindings are okay, FALSE otherwise. */ bool template_template_parm_bindings_ok_p (tree tparms, tree targs) { int i, ntparms = TREE_VEC_LENGTH (tparms); bool ret = true; /* We're dealing with template parms in this process. */ ++processing_template_decl; targs = INNERMOST_TEMPLATE_ARGS (targs); for (i = 0; i < ntparms; ++i) { tree tparm = TREE_VALUE (TREE_VEC_ELT (tparms, i)); tree targ = TREE_VEC_ELT (targs, i); if (TREE_CODE (tparm) == TEMPLATE_DECL && targ) { tree packed_args = NULL_TREE; int idx, len = 1; if (ARGUMENT_PACK_P (targ)) { /* Look inside the argument pack. */ packed_args = ARGUMENT_PACK_ARGS (targ); len = TREE_VEC_LENGTH (packed_args); } for (idx = 0; idx < len; ++idx) { tree targ_parms = NULL_TREE; if (packed_args) /* Extract the next argument from the argument pack. */ targ = TREE_VEC_ELT (packed_args, idx); if (PACK_EXPANSION_P (targ)) /* Look at the pattern of the pack expansion. */ targ = PACK_EXPANSION_PATTERN (targ); /* Extract the template parameters from the template argument. */ if (TREE_CODE (targ) == TEMPLATE_DECL) targ_parms = DECL_INNERMOST_TEMPLATE_PARMS (targ); else if (TREE_CODE (targ) == TEMPLATE_TEMPLATE_PARM) targ_parms = DECL_INNERMOST_TEMPLATE_PARMS (TYPE_NAME (targ)); /* Verify that we can coerce the template template parameters from the template argument to the template parameter. This requires an exact match. */ if (targ_parms && !coerce_template_template_parms (DECL_INNERMOST_TEMPLATE_PARMS (tparm), targ_parms, tf_none, tparm, targs)) { ret = false; goto out; } } } } out: --processing_template_decl; return ret; } /* Convert the indicated template ARG as necessary to match the indicated template PARM. Returns the converted ARG, or error_mark_node if the conversion was unsuccessful. Error and warning messages are issued under control of COMPLAIN. This conversion is for the Ith parameter in the parameter list. ARGS is the full set of template arguments deduced so far. */ static tree convert_template_argument (tree parm, tree arg, tree args, tsubst_flags_t complain, int i, tree in_decl) { tree orig_arg; tree val; int is_type, requires_type, is_tmpl_type, requires_tmpl_type; if (TREE_CODE (arg) == TREE_LIST && TREE_CODE (TREE_VALUE (arg)) == OFFSET_REF) { /* The template argument was the name of some member function. That's usually invalid, but static members are OK. In any case, grab the underlying fields/functions and issue an error later if required. */ orig_arg = TREE_VALUE (arg); TREE_TYPE (arg) = unknown_type_node; } orig_arg = arg; requires_tmpl_type = TREE_CODE (parm) == TEMPLATE_DECL; requires_type = (TREE_CODE (parm) == TYPE_DECL || requires_tmpl_type); /* When determining whether an argument pack expansion is a template, look at the pattern. */ if (TREE_CODE (arg) == TYPE_PACK_EXPANSION) arg = PACK_EXPANSION_PATTERN (arg); /* Deal with an injected-class-name used as a template template arg. */ if (requires_tmpl_type && CLASS_TYPE_P (arg)) { tree t = maybe_get_template_decl_from_type_decl (TYPE_NAME (arg)); if (TREE_CODE (t) == TEMPLATE_DECL) { if (complain & tf_warning_or_error) pedwarn (input_location, OPT_pedantic, "injected-class-name %qD" " used as template template argument", TYPE_NAME (arg)); else if (flag_pedantic_errors) t = arg; arg = t; } } is_tmpl_type = ((TREE_CODE (arg) == TEMPLATE_DECL && TREE_CODE (DECL_TEMPLATE_RESULT (arg)) == TYPE_DECL) || TREE_CODE (arg) == TEMPLATE_TEMPLATE_PARM || TREE_CODE (arg) == UNBOUND_CLASS_TEMPLATE); if (is_tmpl_type && (TREE_CODE (arg) == TEMPLATE_TEMPLATE_PARM || TREE_CODE (arg) == UNBOUND_CLASS_TEMPLATE)) arg = TYPE_STUB_DECL (arg); is_type = TYPE_P (arg) || is_tmpl_type; if (requires_type && ! is_type && TREE_CODE (arg) == SCOPE_REF && TREE_CODE (TREE_OPERAND (arg, 0)) == TEMPLATE_TYPE_PARM) { permerror (input_location, "to refer to a type member of a template parameter, " "use %<typename %E%>", orig_arg); orig_arg = make_typename_type (TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1), typename_type, complain & tf_error); arg = orig_arg; is_type = 1; } if (is_type != requires_type) { if (in_decl) { if (complain & tf_error) { error ("type/value mismatch at argument %d in template " "parameter list for %qD", i + 1, in_decl); if (is_type) error (" expected a constant of type %qT, got %qT", TREE_TYPE (parm), (DECL_P (arg) ? DECL_NAME (arg) : orig_arg)); else if (requires_tmpl_type) error (" expected a class template, got %qE", orig_arg); else error (" expected a type, got %qE", orig_arg); } } return error_mark_node; } if (is_tmpl_type ^ requires_tmpl_type) { if (in_decl && (complain & tf_error)) { error ("type/value mismatch at argument %d in template " "parameter list for %qD", i + 1, in_decl); if (is_tmpl_type) error (" expected a type, got %qT", DECL_NAME (arg)); else error (" expected a class template, got %qT", orig_arg); } return error_mark_node; } if (is_type) { if (requires_tmpl_type) { if (TREE_CODE (TREE_TYPE (arg)) == UNBOUND_CLASS_TEMPLATE) /* The number of argument required is not known yet. Just accept it for now. */ val = TREE_TYPE (arg); else { tree parmparm = DECL_INNERMOST_TEMPLATE_PARMS (parm); tree argparm; argparm = DECL_INNERMOST_TEMPLATE_PARMS (arg); if (coerce_template_template_parms (parmparm, argparm, complain, in_decl, args)) { val = arg; /* TEMPLATE_TEMPLATE_PARM node is preferred over TEMPLATE_DECL. */ if (val != error_mark_node) { if (DECL_TEMPLATE_TEMPLATE_PARM_P (val)) val = TREE_TYPE (val); if (TREE_CODE (orig_arg) == TYPE_PACK_EXPANSION) val = make_pack_expansion (val); } } else { if (in_decl && (complain & tf_error)) { error ("type/value mismatch at argument %d in " "template parameter list for %qD", i + 1, in_decl); error (" expected a template of type %qD, got %qT", parm, orig_arg); } val = error_mark_node; } } } else val = orig_arg; /* We only form one instance of each template specialization. Therefore, if we use a non-canonical variant (i.e., a typedef), any future messages referring to the type will use the typedef, which is confusing if those future uses do not themselves also use the typedef. */ if (TYPE_P (val)) val = strip_typedefs (val); } else { tree t = tsubst (TREE_TYPE (parm), args, complain, in_decl); if (invalid_nontype_parm_type_p (t, complain)) return error_mark_node; if (template_parameter_pack_p (parm) && ARGUMENT_PACK_P (orig_arg)) { if (same_type_p (t, TREE_TYPE (orig_arg))) val = orig_arg; else { /* Not sure if this is reachable, but it doesn't hurt to be robust. */ error ("type mismatch in nontype parameter pack"); val = error_mark_node; } } else if (!uses_template_parms (orig_arg) && !uses_template_parms (t)) /* We used to call digest_init here. However, digest_init will report errors, which we don't want when complain is zero. More importantly, digest_init will try too hard to convert things: for example, `0' should not be converted to pointer type at this point according to the standard. Accepting this is not merely an extension, since deciding whether or not these conversions can occur is part of determining which function template to call, or whether a given explicit argument specification is valid. */ val = convert_nontype_argument (t, orig_arg); else val = orig_arg; if (val == NULL_TREE) val = error_mark_node; else if (val == error_mark_node && (complain & tf_error)) error ("could not convert template argument %qE to %qT", orig_arg, t); if (TREE_CODE (val) == SCOPE_REF) { /* Strip typedefs from the SCOPE_REF. */ tree type = strip_typedefs (TREE_TYPE (val)); tree scope = strip_typedefs (TREE_OPERAND (val, 0)); val = build_qualified_name (type, scope, TREE_OPERAND (val, 1), QUALIFIED_NAME_IS_TEMPLATE (val)); } } return val; } /* Coerces the remaining template arguments in INNER_ARGS (from ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS. Returns the coerced argument pack. PARM_IDX is the position of this parameter in the template parameter list. ARGS is the original template argument list. */ static tree coerce_template_parameter_pack (tree parms, int parm_idx, tree args, tree inner_args, int arg_idx, tree new_args, int* lost, tree in_decl, tsubst_flags_t complain) { tree parm = TREE_VEC_ELT (parms, parm_idx); int nargs = inner_args ? NUM_TMPL_ARGS (inner_args) : 0; tree packed_args; tree argument_pack; tree packed_types = NULL_TREE; if (arg_idx > nargs) arg_idx = nargs; packed_args = make_tree_vec (nargs - arg_idx); if (TREE_CODE (TREE_VALUE (parm)) == PARM_DECL && uses_parameter_packs (TREE_TYPE (TREE_VALUE (parm)))) { /* When the template parameter is a non-type template parameter pack whose type uses parameter packs, we need to look at each of the template arguments separately. Build a vector of the types for these non-type template parameters in PACKED_TYPES. */ tree expansion = make_pack_expansion (TREE_TYPE (TREE_VALUE (parm))); packed_types = tsubst_pack_expansion (expansion, args, complain, in_decl); if (packed_types == error_mark_node) return error_mark_node; /* Check that we have the right number of arguments. */ if (arg_idx < nargs && !PACK_EXPANSION_P (TREE_VEC_ELT (inner_args, arg_idx)) && nargs - arg_idx != TREE_VEC_LENGTH (packed_types)) { int needed_parms = TREE_VEC_LENGTH (parms) - 1 + TREE_VEC_LENGTH (packed_types); error ("wrong number of template arguments (%d, should be %d)", nargs, needed_parms); return error_mark_node; } /* If we aren't able to check the actual arguments now (because they haven't been expanded yet), we can at least verify that all of the types used for the non-type template parameter pack are, in fact, valid for non-type template parameters. */ if (arg_idx < nargs && PACK_EXPANSION_P (TREE_VEC_ELT (inner_args, arg_idx))) { int j, len = TREE_VEC_LENGTH (packed_types); for (j = 0; j < len; ++j) { tree t = TREE_VEC_ELT (packed_types, j); if (invalid_nontype_parm_type_p (t, complain)) return error_mark_node; } } } /* Convert the remaining arguments, which will be a part of the parameter pack "parm". */ for (; arg_idx < nargs; ++arg_idx) { tree arg = TREE_VEC_ELT (inner_args, arg_idx); tree actual_parm = TREE_VALUE (parm); if (packed_types && !PACK_EXPANSION_P (arg)) { /* When we have a vector of types (corresponding to the non-type template parameter pack that uses parameter packs in its type, as mention above), and the argument is not an expansion (which expands to a currently unknown number of arguments), clone the parm and give it the next type in PACKED_TYPES. */ actual_parm = copy_node (actual_parm); TREE_TYPE (actual_parm) = TREE_VEC_ELT (packed_types, arg_idx - parm_idx); } if (arg != error_mark_node) arg = convert_template_argument (actual_parm, arg, new_args, complain, parm_idx, in_decl); if (arg == error_mark_node) (*lost)++; TREE_VEC_ELT (packed_args, arg_idx - parm_idx) = arg; } if (TREE_CODE (TREE_VALUE (parm)) == TYPE_DECL || TREE_CODE (TREE_VALUE (parm)) == TEMPLATE_DECL) argument_pack = cxx_make_type (TYPE_ARGUMENT_PACK); else { argument_pack = make_node (NONTYPE_ARGUMENT_PACK); TREE_TYPE (argument_pack) = tsubst (TREE_TYPE (TREE_VALUE (parm)), new_args, complain, in_decl); TREE_CONSTANT (argument_pack) = 1; } SET_ARGUMENT_PACK_ARGS (argument_pack, packed_args); #ifdef ENABLE_CHECKING SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (packed_args, TREE_VEC_LENGTH (packed_args)); #endif return argument_pack; } /* Convert all template arguments to their appropriate types, and return a vector containing the innermost resulting template arguments. If any error occurs, return error_mark_node. Error and warning messages are issued under control of COMPLAIN. If REQUIRE_ALL_ARGS is false, argument deduction will be performed for arguments not specified in ARGS. Otherwise, if USE_DEFAULT_ARGS is true, default arguments will be used to fill in unspecified arguments. If REQUIRE_ALL_ARGS is true, but USE_DEFAULT_ARGS is false, then all arguments must be specified in ARGS. */ static tree coerce_template_parms (tree parms, tree args, tree in_decl, tsubst_flags_t complain, bool require_all_args, bool use_default_args) { int nparms, nargs, parm_idx, arg_idx, lost = 0; tree inner_args; tree new_args; tree new_inner_args; int saved_unevaluated_operand; int saved_inhibit_evaluation_warnings; /* When used as a boolean value, indicates whether this is a variadic template parameter list. Since it's an int, we can also subtract it from nparms to get the number of non-variadic parameters. */ int variadic_p = 0; nparms = TREE_VEC_LENGTH (parms); /* Determine if there are any parameter packs. */ for (parm_idx = 0; parm_idx < nparms; ++parm_idx) { tree tparm = TREE_VALUE (TREE_VEC_ELT (parms, parm_idx)); if (template_parameter_pack_p (tparm)) ++variadic_p; } inner_args = INNERMOST_TEMPLATE_ARGS (args); /* If there are 0 or 1 parameter packs, we need to expand any argument packs so that we can deduce a parameter pack from some non-packed args followed by an argument pack, as in variadic85.C. If there are more than that, we need to leave argument packs intact so the arguments are assigned to the right parameter packs. This should only happen when dealing with a nested class inside a partial specialization of a class template, as in variadic92.C. */ if (variadic_p <= 1) inner_args = expand_template_argument_pack (inner_args); nargs = inner_args ? NUM_TMPL_ARGS (inner_args) : 0; if ((nargs > nparms && !variadic_p) || (nargs < nparms - variadic_p && require_all_args && (!use_default_args || (TREE_VEC_ELT (parms, nargs) != error_mark_node && !TREE_PURPOSE (TREE_VEC_ELT (parms, nargs)))))) { if (complain & tf_error) { const char *or_more = ""; if (variadic_p) { or_more = " or more"; --nparms; } error ("wrong number of template arguments (%d, should be %d%s)", nargs, nparms, or_more); if (in_decl) error ("provided for %q+D", in_decl); } return error_mark_node; } /* We need to evaluate the template arguments, even though this template-id may be nested within a "sizeof". */ saved_unevaluated_operand = cp_unevaluated_operand; cp_unevaluated_operand = 0; saved_inhibit_evaluation_warnings = c_inhibit_evaluation_warnings; c_inhibit_evaluation_warnings = 0; new_inner_args = make_tree_vec (nparms); new_args = add_outermost_template_args (args, new_inner_args); for (parm_idx = 0, arg_idx = 0; parm_idx < nparms; parm_idx++, arg_idx++) { tree arg; tree parm; /* Get the Ith template parameter. */ parm = TREE_VEC_ELT (parms, parm_idx); if (parm == error_mark_node) { TREE_VEC_ELT (new_inner_args, arg_idx) = error_mark_node; continue; } /* Calculate the next argument. */ if (arg_idx < nargs) arg = TREE_VEC_ELT (inner_args, arg_idx); else arg = NULL_TREE; if (template_parameter_pack_p (TREE_VALUE (parm)) && !(arg && ARGUMENT_PACK_P (arg))) { /* All remaining arguments will be placed in the template parameter pack PARM. */ arg = coerce_template_parameter_pack (parms, parm_idx, args, inner_args, arg_idx, new_args, &lost, in_decl, complain); /* Store this argument. */ if (arg == error_mark_node) lost++; TREE_VEC_ELT (new_inner_args, parm_idx) = arg; /* We are done with all of the arguments. */ arg_idx = nargs; continue; } else if (arg) { if (PACK_EXPANSION_P (arg)) { if (complain & tf_error) { /* FIXME this restriction was removed by N2555; see bug 35722. */ /* If ARG is a pack expansion, but PARM is not a template parameter pack (if it were, we would have handled it above), we're trying to expand into a fixed-length argument list. */ if (TREE_CODE (arg) == EXPR_PACK_EXPANSION) sorry ("cannot expand %<%E%> into a fixed-length " "argument list", arg); else sorry ("cannot expand %<%T%> into a fixed-length " "argument list", arg); } return error_mark_node; } } else if (require_all_args) { /* There must be a default arg in this case. */ arg = tsubst_template_arg (TREE_PURPOSE (parm), new_args, complain, in_decl); /* The position of the first default template argument, is also the number of non-defaulted arguments in NEW_INNER_ARGS. Record that. */ if (!NON_DEFAULT_TEMPLATE_ARGS_COUNT (new_inner_args)) SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (new_inner_args, arg_idx); } else break; if (arg == error_mark_node) { if (complain & tf_error) error ("template argument %d is invalid", arg_idx + 1); } else if (!arg) /* This only occurs if there was an error in the template parameter list itself (which we would already have reported) that we are trying to recover from, e.g., a class template with a parameter list such as template<typename..., typename>. */ return error_mark_node; else arg = convert_template_argument (TREE_VALUE (parm), arg, new_args, complain, parm_idx, in_decl); if (arg == error_mark_node) lost++; TREE_VEC_ELT (new_inner_args, arg_idx) = arg; } cp_unevaluated_operand = saved_unevaluated_operand; c_inhibit_evaluation_warnings = saved_inhibit_evaluation_warnings; if (lost) return error_mark_node; #ifdef ENABLE_CHECKING if (!NON_DEFAULT_TEMPLATE_ARGS_COUNT (new_inner_args)) SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (new_inner_args, TREE_VEC_LENGTH (new_inner_args)); #endif return new_inner_args; } /* Returns 1 if template args OT and NT are equivalent. */ static int template_args_equal (tree ot, tree nt) { if (nt == ot) return 1; if (TREE_CODE (nt) == TREE_VEC) /* For member templates */ return TREE_CODE (ot) == TREE_VEC && comp_template_args (ot, nt); else if (PACK_EXPANSION_P (ot)) return PACK_EXPANSION_P (nt) && template_args_equal (PACK_EXPANSION_PATTERN (ot), PACK_EXPANSION_PATTERN (nt)); else if (ARGUMENT_PACK_P (ot)) { int i, len; tree opack, npack; if (!ARGUMENT_PACK_P (nt)) return 0; opack = ARGUMENT_PACK_ARGS (ot); npack = ARGUMENT_PACK_ARGS (nt); len = TREE_VEC_LENGTH (opack); if (TREE_VEC_LENGTH (npack) != len) return 0; for (i = 0; i < len; ++i) if (!template_args_equal (TREE_VEC_ELT (opack, i), TREE_VEC_ELT (npack, i))) return 0; return 1; } else if (ot && TREE_CODE (ot) == ARGUMENT_PACK_SELECT) { /* We get here probably because we are in the middle of substituting into the pattern of a pack expansion. In that case the ARGUMENT_PACK_SELECT temporarily replaces the pack argument we are interested in. So we want to use the initial pack argument for the comparison. */ ot = ARGUMENT_PACK_SELECT_FROM_PACK (ot); if (nt && TREE_CODE (nt) == ARGUMENT_PACK_SELECT) nt = ARGUMENT_PACK_SELECT_FROM_PACK (nt); return template_args_equal (ot, nt); } else if (TYPE_P (nt)) return TYPE_P (ot) && same_type_p (ot, nt); else if (TREE_CODE (ot) == TREE_VEC || TYPE_P (ot)) return 0; else return cp_tree_equal (ot, nt); } /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of template arguments. Returns 0 otherwise. */ int comp_template_args (tree oldargs, tree newargs) { int i; if (TREE_VEC_LENGTH (oldargs) != TREE_VEC_LENGTH (newargs)) return 0; for (i = 0; i < TREE_VEC_LENGTH (oldargs); ++i) { tree nt = TREE_VEC_ELT (newargs, i); tree ot = TREE_VEC_ELT (oldargs, i); if (! template_args_equal (ot, nt)) return 0; } return 1; } static void add_pending_template (tree d) { tree ti = (TYPE_P (d) ? CLASSTYPE_TEMPLATE_INFO (d) : DECL_TEMPLATE_INFO (d)); struct pending_template *pt; int level; if (TI_PENDING_TEMPLATE_FLAG (ti)) return; /* We are called both from instantiate_decl, where we've already had a tinst_level pushed, and instantiate_template, where we haven't. Compensate. */ level = !current_tinst_level || current_tinst_level->decl != d; if (level) push_tinst_level (d); pt = GGC_NEW (struct pending_template); pt->next = NULL; pt->tinst = current_tinst_level; if (last_pending_template) last_pending_template->next = pt; else pending_templates = pt; last_pending_template = pt; TI_PENDING_TEMPLATE_FLAG (ti) = 1; if (level) pop_tinst_level (); } /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and ARGLIST. Valid choices for FNS are given in the cp-tree.def documentation for TEMPLATE_ID_EXPR. */ tree lookup_template_function (tree fns, tree arglist) { tree type; if (fns == error_mark_node || arglist == error_mark_node) return error_mark_node; gcc_assert (!arglist || TREE_CODE (arglist) == TREE_VEC); gcc_assert (fns && (is_overloaded_fn (fns) || TREE_CODE (fns) == IDENTIFIER_NODE)); if (BASELINK_P (fns)) { BASELINK_FUNCTIONS (fns) = build2 (TEMPLATE_ID_EXPR, unknown_type_node, BASELINK_FUNCTIONS (fns), arglist); return fns; } type = TREE_TYPE (fns); if (TREE_CODE (fns) == OVERLOAD || !type) type = unknown_type_node; return build2 (TEMPLATE_ID_EXPR, type, fns, arglist); } /* Within the scope of a template class S<T>, the name S gets bound (in build_self_reference) to a TYPE_DECL for the class, not a TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type, or one of its enclosing classes, and that type is a template, return the associated TEMPLATE_DECL. Otherwise, the original DECL is returned. Also handle the case when DECL is a TREE_LIST of ambiguous injected-class-names from different bases. */ tree maybe_get_template_decl_from_type_decl (tree decl) { if (decl == NULL_TREE) return decl; /* DR 176: A lookup that finds an injected-class-name (10.2 [class.member.lookup]) can result in an ambiguity in certain cases (for example, if it is found in more than one base class). If all of the injected-class-names that are found refer to specializations of the same class template, and if the name is followed by a template-argument-list, the reference refers to the class template itself and not a specialization thereof, and is not ambiguous. */ if (TREE_CODE (decl) == TREE_LIST) { tree t, tmpl = NULL_TREE; for (t = decl; t; t = TREE_CHAIN (t)) { tree elt = maybe_get_template_decl_from_type_decl (TREE_VALUE (t)); if (!tmpl) tmpl = elt; else if (tmpl != elt) break; } if (tmpl && t == NULL_TREE) return tmpl; else return decl; } return (decl != NULL_TREE && DECL_SELF_REFERENCE_P (decl) && CLASSTYPE_TEMPLATE_INFO (TREE_TYPE (decl))) ? CLASSTYPE_TI_TEMPLATE (TREE_TYPE (decl)) : decl; } /* Given an IDENTIFIER_NODE (type TEMPLATE_DECL) and a chain of parameters, find the desired type. D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments. IN_DECL, if non-NULL, is the template declaration we are trying to instantiate. If ENTERING_SCOPE is nonzero, we are about to enter the scope of the class we are looking up. Issue error and warning messages under control of COMPLAIN. If the template class is really a local class in a template function, then the FUNCTION_CONTEXT is the function in which it is being instantiated. ??? Note that this function is currently called *twice* for each template-id: the first time from the parser, while creating the incomplete type (finish_template_type), and the second type during the real instantiation (instantiate_template_class). This is surely something that we want to avoid. It also causes some problems with argument coercion (see convert_nontype_argument for more information on this). */ tree lookup_template_class (tree d1, tree arglist, tree in_decl, tree context, int entering_scope, tsubst_flags_t complain) { tree templ = NULL_TREE, parmlist; tree t; spec_entry **slot; spec_entry *entry; spec_entry elt; hashval_t hash; timevar_push (TV_NAME_LOOKUP); if (TREE_CODE (d1) == IDENTIFIER_NODE) { tree value = innermost_non_namespace_value (d1); if (value && DECL_TEMPLATE_TEMPLATE_PARM_P (value)) templ = value; else { if (context) push_decl_namespace (context); templ = lookup_name (d1); templ = maybe_get_template_decl_from_type_decl (templ); if (context) pop_decl_namespace (); } if (templ) context = DECL_CONTEXT (templ); } else if (TREE_CODE (d1) == TYPE_DECL && MAYBE_CLASS_TYPE_P (TREE_TYPE (d1))) { tree type = TREE_TYPE (d1); /* If we are declaring a constructor, say A<T>::A<T>, we will get an implicit typename for the second A. Deal with it. */ if (TREE_CODE (type) == TYPENAME_TYPE && TREE_TYPE (type)) type = TREE_TYPE (type); if (CLASSTYPE_TEMPLATE_INFO (type)) { templ = CLASSTYPE_TI_TEMPLATE (type); d1 = DECL_NAME (templ); } } else if (TREE_CODE (d1) == ENUMERAL_TYPE || (TYPE_P (d1) && MAYBE_CLASS_TYPE_P (d1))) { templ = TYPE_TI_TEMPLATE (d1); d1 = DECL_NAME (templ); } else if (TREE_CODE (d1) == TEMPLATE_DECL && DECL_TEMPLATE_RESULT (d1) && TREE_CODE (DECL_TEMPLATE_RESULT (d1)) == TYPE_DECL) { templ = d1; d1 = DECL_NAME (templ); context = DECL_CONTEXT (templ); } /* Issue an error message if we didn't find a template. */ if (! templ) { if (complain & tf_error) error ("%qT is not a template", d1); POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, error_mark_node); } if (TREE_CODE (templ) != TEMPLATE_DECL /* Make sure it's a user visible template, if it was named by the user. */ || ((complain & tf_user) && !DECL_TEMPLATE_PARM_P (templ) && !PRIMARY_TEMPLATE_P (templ))) { if (complain & tf_error) { error ("non-template type %qT used as a template", d1); if (in_decl) error ("for template declaration %q+D", in_decl); } POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, error_mark_node); } complain &= ~tf_user; if (DECL_TEMPLATE_TEMPLATE_PARM_P (templ)) { /* Create a new TEMPLATE_DECL and TEMPLATE_TEMPLATE_PARM node to store template arguments */ tree parm; tree arglist2; tree outer; parmlist = DECL_INNERMOST_TEMPLATE_PARMS (templ); /* Consider an example where a template template parameter declared as template <class T, class U = std::allocator<T> > class TT The template parameter level of T and U are one level larger than of TT. To proper process the default argument of U, say when an instantiation `TT<int>' is seen, we need to build the full arguments containing {int} as the innermost level. Outer levels, available when not appearing as default template argument, can be obtained from the arguments of the enclosing template. Suppose that TT is later substituted with std::vector. The above instantiation is `TT<int, std::allocator<T> >' with TT at level 1, and T at level 2, while the template arguments at level 1 becomes {std::vector} and the inner level 2 is {int}. */ outer = DECL_CONTEXT (templ); if (outer) outer = TI_ARGS (get_template_info (DECL_TEMPLATE_RESULT (outer))); else if (current_template_parms) /* This is an argument of the current template, so we haven't set DECL_CONTEXT yet. */ outer = current_template_args (); if (outer) arglist = add_to_template_args (outer, arglist); arglist2 = coerce_template_parms (parmlist, arglist, templ, complain, /*require_all_args=*/true, /*use_default_args=*/true); if (arglist2 == error_mark_node || (!uses_template_parms (arglist2) && check_instantiated_args (templ, arglist2, complain))) POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, error_mark_node); parm = bind_template_template_parm (TREE_TYPE (templ), arglist2); POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, parm); } else { tree template_type = TREE_TYPE (templ); tree gen_tmpl; tree type_decl; tree found = NULL_TREE; int arg_depth; int parm_depth; int is_dependent_type; int use_partial_inst_tmpl = false; gen_tmpl = most_general_template (templ); parmlist = DECL_TEMPLATE_PARMS (gen_tmpl); parm_depth = TMPL_PARMS_DEPTH (parmlist); arg_depth = TMPL_ARGS_DEPTH (arglist); if (arg_depth == 1 && parm_depth > 1) { /* We've been given an incomplete set of template arguments. For example, given: template <class T> struct S1 { template <class U> struct S2 {}; template <class U> struct S2<U*> {}; }; we will be called with an ARGLIST of `U*', but the TEMPLATE will be `template <class T> template <class U> struct S1<T>::S2'. We must fill in the missing arguments. */ arglist = add_outermost_template_args (TYPE_TI_ARGS (TREE_TYPE (templ)), arglist); arg_depth = TMPL_ARGS_DEPTH (arglist); } /* Now we should have enough arguments. */ gcc_assert (parm_depth == arg_depth); /* From here on, we're only interested in the most general template. */ /* Calculate the BOUND_ARGS. These will be the args that are actually tsubst'd into the definition to create the instantiation. */ if (parm_depth > 1) { /* We have multiple levels of arguments to coerce, at once. */ int i; int saved_depth = TMPL_ARGS_DEPTH (arglist); tree bound_args = make_tree_vec (parm_depth); for (i = saved_depth, t = DECL_TEMPLATE_PARMS (gen_tmpl); i > 0 && t != NULL_TREE; --i, t = TREE_CHAIN (t)) { tree a = coerce_template_parms (TREE_VALUE (t), arglist, gen_tmpl, complain, /*require_all_args=*/true, /*use_default_args=*/true); /* Don't process further if one of the levels fails. */ if (a == error_mark_node) { /* Restore the ARGLIST to its full size. */ TREE_VEC_LENGTH (arglist) = saved_depth; POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, error_mark_node); } SET_TMPL_ARGS_LEVEL (bound_args, i, a); /* We temporarily reduce the length of the ARGLIST so that coerce_template_parms will see only the arguments corresponding to the template parameters it is examining. */ TREE_VEC_LENGTH (arglist)--; } /* Restore the ARGLIST to its full size. */ TREE_VEC_LENGTH (arglist) = saved_depth; arglist = bound_args; } else arglist = coerce_template_parms (INNERMOST_TEMPLATE_PARMS (parmlist), INNERMOST_TEMPLATE_ARGS (arglist), gen_tmpl, complain, /*require_all_args=*/true, /*use_default_args=*/true); if (arglist == error_mark_node) /* We were unable to bind the arguments. */ POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, error_mark_node); /* In the scope of a template class, explicit references to the template class refer to the type of the template, not any instantiation of it. For example, in: template <class T> class C { void f(C<T>); } the `C<T>' is just the same as `C'. Outside of the class, however, such a reference is an instantiation. */ if ((entering_scope || !PRIMARY_TEMPLATE_P (gen_tmpl) || currently_open_class (template_type)) /* comp_template_args is expensive, check it last. */ && comp_template_args (TYPE_TI_ARGS (template_type), arglist)) POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, template_type); /* If we already have this specialization, return it. */ elt.tmpl = gen_tmpl; elt.args = arglist; hash = hash_specialization (&elt); entry = (spec_entry *) htab_find_with_hash (type_specializations, &elt, hash); if (entry) POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, entry->spec); is_dependent_type = uses_template_parms (arglist); /* If the deduced arguments are invalid, then the binding failed. */ if (!is_dependent_type && check_instantiated_args (gen_tmpl, INNERMOST_TEMPLATE_ARGS (arglist), complain)) POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, error_mark_node); if (!is_dependent_type && !PRIMARY_TEMPLATE_P (gen_tmpl) && !LAMBDA_TYPE_P (TREE_TYPE (gen_tmpl)) && TREE_CODE (CP_DECL_CONTEXT (gen_tmpl)) == NAMESPACE_DECL) { found = xref_tag_from_type (TREE_TYPE (gen_tmpl), DECL_NAME (gen_tmpl), /*tag_scope=*/ts_global); POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, found); } context = tsubst (DECL_CONTEXT (gen_tmpl), arglist, complain, in_decl); if (!context) context = global_namespace; /* Create the type. */ if (TREE_CODE (template_type) == ENUMERAL_TYPE) { if (!is_dependent_type) { set_current_access_from_decl (TYPE_NAME (template_type)); t = start_enum (TYPE_IDENTIFIER (template_type), tsubst (ENUM_UNDERLYING_TYPE (template_type), arglist, complain, in_decl), SCOPED_ENUM_P (template_type)); } else { /* We don't want to call start_enum for this type, since the values for the enumeration constants may involve template parameters. And, no one should be interested in the enumeration constants for such a type. */ t = cxx_make_type (ENUMERAL_TYPE); SET_SCOPED_ENUM_P (t, SCOPED_ENUM_P (template_type)); } } else { t = make_class_type (TREE_CODE (template_type)); CLASSTYPE_DECLARED_CLASS (t) = CLASSTYPE_DECLARED_CLASS (template_type); SET_CLASSTYPE_IMPLICIT_INSTANTIATION (t); TYPE_FOR_JAVA (t) = TYPE_FOR_JAVA (template_type); /* A local class. Make sure the decl gets registered properly. */ if (context == current_function_decl) pushtag (DECL_NAME (gen_tmpl), t, /*tag_scope=*/ts_current); if (comp_template_args (CLASSTYPE_TI_ARGS (template_type), arglist)) /* This instantiation is another name for the primary template type. Set the TYPE_CANONICAL field appropriately. */ TYPE_CANONICAL (t) = template_type; else if (any_template_arguments_need_structural_equality_p (arglist)) /* Some of the template arguments require structural equality testing, so this template class requires structural equality testing. */ SET_TYPE_STRUCTURAL_EQUALITY (t); } /* If we called start_enum or pushtag above, this information will already be set up. */ if (!TYPE_NAME (t)) { TYPE_CONTEXT (t) = FROB_CONTEXT (context); type_decl = create_implicit_typedef (DECL_NAME (gen_tmpl), t); DECL_CONTEXT (type_decl) = TYPE_CONTEXT (t); DECL_SOURCE_LOCATION (type_decl) = DECL_SOURCE_LOCATION (TYPE_STUB_DECL (template_type)); } else type_decl = TYPE_NAME (t); TREE_PRIVATE (type_decl) = TREE_PRIVATE (TYPE_STUB_DECL (template_type)); TREE_PROTECTED (type_decl) = TREE_PROTECTED (TYPE_STUB_DECL (template_type)); if (CLASSTYPE_VISIBILITY_SPECIFIED (template_type)) { DECL_VISIBILITY_SPECIFIED (type_decl) = 1; DECL_VISIBILITY (type_decl) = CLASSTYPE_VISIBILITY (template_type); } /* Let's consider the explicit specialization of a member of a class template specialization that is implicitely instantiated, e.g.: template<class T> struct S { template<class U> struct M {}; //#0 }; template<> template<> struct S<int>::M<char> //#1 { int i; }; [temp.expl.spec]/4 says this is valid. In this case, when we write: S<int>::M<char> m; M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from the one of #0. When we encounter #1, we want to store the partial instantiation of M (template<class T> S<int>::M<T>) in it's CLASSTYPE_TI_TEMPLATE. For all cases other than this "explicit specialization of member of a class template", we just want to store the most general template into the CLASSTYPE_TI_TEMPLATE of M. This case of "explicit specialization of member of a class template" only happens when: 1/ the enclosing class is an instantiation of, and therefore not the same as, the context of the most general template, and 2/ we aren't looking at the partial instantiation itself, i.e. the innermost arguments are not the same as the innermost parms of the most general template. So it's only when 1/ and 2/ happens that we want to use the partial instantiation of the member template in lieu of its most general template. */ if (PRIMARY_TEMPLATE_P (gen_tmpl) && TMPL_ARGS_HAVE_MULTIPLE_LEVELS (arglist) /* the enclosing class must be an instantiation... */ && CLASS_TYPE_P (context) && !same_type_p (context, DECL_CONTEXT (gen_tmpl))) { tree partial_inst_args; TREE_VEC_LENGTH (arglist)--; ++processing_template_decl; partial_inst_args = tsubst (INNERMOST_TEMPLATE_ARGS (CLASSTYPE_TI_ARGS (TREE_TYPE (gen_tmpl))), arglist, complain, NULL_TREE); --processing_template_decl; TREE_VEC_LENGTH (arglist)++; use_partial_inst_tmpl = /*...and we must not be looking at the partial instantiation itself. */ !comp_template_args (INNERMOST_TEMPLATE_ARGS (arglist), partial_inst_args); } if (!use_partial_inst_tmpl) /* This case is easy; there are no member templates involved. */ found = gen_tmpl; else { /* This is a full instantiation of a member template. Find the partial instantiation of which this is an instance. */ /* Temporarily reduce by one the number of levels in the ARGLIST so as to avoid comparing the last set of arguments. */ TREE_VEC_LENGTH (arglist)--; found = tsubst (gen_tmpl, arglist, complain, NULL_TREE); TREE_VEC_LENGTH (arglist)++; found = CLASSTYPE_TI_TEMPLATE (found); } SET_TYPE_TEMPLATE_INFO (t, build_template_info (found, arglist)); elt.spec = t; slot = (spec_entry **) htab_find_slot_with_hash (type_specializations, &elt, hash, INSERT); *slot = GGC_NEW (spec_entry); **slot = elt; /* Note this use of the partial instantiation so we can check it later in maybe_process_partial_specialization. */ DECL_TEMPLATE_INSTANTIATIONS (templ) = tree_cons (arglist, t, DECL_TEMPLATE_INSTANTIATIONS (templ)); if (TREE_CODE (t) == ENUMERAL_TYPE && !is_dependent_type) /* Now that the type has been registered on the instantiations list, we set up the enumerators. Because the enumeration constants may involve the enumeration type itself, we make sure to register the type first, and then create the constants. That way, doing tsubst_expr for the enumeration constants won't result in recursive calls here; we'll find the instantiation and exit above. */ tsubst_enum (template_type, t, arglist); if (is_dependent_type) /* If the type makes use of template parameters, the code that generates debugging information will crash. */ DECL_IGNORED_P (TYPE_STUB_DECL (t)) = 1; /* Possibly limit visibility based on template args. */ TREE_PUBLIC (type_decl) = 1; determine_visibility (type_decl); POP_TIMEVAR_AND_RETURN (TV_NAME_LOOKUP, t); } timevar_pop (TV_NAME_LOOKUP); } struct pair_fn_data { tree_fn_t fn; void *data; /* True when we should also visit template parameters that occur in non-deduced contexts. */ bool include_nondeduced_p; struct pointer_set_t *visited; }; /* Called from for_each_template_parm via walk_tree. */ static tree for_each_template_parm_r (tree *tp, int *walk_subtrees, void *d) { tree t = *tp; struct pair_fn_data *pfd = (struct pair_fn_data *) d; tree_fn_t fn = pfd->fn; void *data = pfd->data; if (TYPE_P (t) && (pfd->include_nondeduced_p || TREE_CODE (t) != TYPENAME_TYPE) && for_each_template_parm (TYPE_CONTEXT (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; switch (TREE_CODE (t)) { case RECORD_TYPE: if (TYPE_PTRMEMFUNC_P (t)) break; /* Fall through. */ case UNION_TYPE: case ENUMERAL_TYPE: if (!TYPE_TEMPLATE_INFO (t)) *walk_subtrees = 0; else if (for_each_template_parm (TI_ARGS (TYPE_TEMPLATE_INFO (t)), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; break; case INTEGER_TYPE: if (for_each_template_parm (TYPE_MIN_VALUE (t), fn, data, pfd->visited, pfd->include_nondeduced_p) || for_each_template_parm (TYPE_MAX_VALUE (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; break; case METHOD_TYPE: /* Since we're not going to walk subtrees, we have to do this explicitly here. */ if (for_each_template_parm (TYPE_METHOD_BASETYPE (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; /* Fall through. */ case FUNCTION_TYPE: /* Check the return type. */ if (for_each_template_parm (TREE_TYPE (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; /* Check the parameter types. Since default arguments are not instantiated until they are needed, the TYPE_ARG_TYPES may contain expressions that involve template parameters. But, no-one should be looking at them yet. And, once they're instantiated, they don't contain template parameters, so there's no point in looking at them then, either. */ { tree parm; for (parm = TYPE_ARG_TYPES (t); parm; parm = TREE_CHAIN (parm)) if (for_each_template_parm (TREE_VALUE (parm), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; /* Since we've already handled the TYPE_ARG_TYPES, we don't want walk_tree walking into them itself. */ *walk_subtrees = 0; } break; case TYPEOF_TYPE: if (pfd->include_nondeduced_p && for_each_template_parm (TYPE_FIELDS (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; break; case FUNCTION_DECL: case VAR_DECL: if (DECL_LANG_SPECIFIC (t) && DECL_TEMPLATE_INFO (t) && for_each_template_parm (DECL_TI_ARGS (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; /* Fall through. */ case PARM_DECL: case CONST_DECL: if (TREE_CODE (t) == CONST_DECL && DECL_TEMPLATE_PARM_P (t) && for_each_template_parm (DECL_INITIAL (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; if (DECL_CONTEXT (t) && pfd->include_nondeduced_p && for_each_template_parm (DECL_CONTEXT (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; break; case BOUND_TEMPLATE_TEMPLATE_PARM: /* Record template parameters such as `T' inside `TT<T>'. */ if (for_each_template_parm (TYPE_TI_ARGS (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; /* Fall through. */ case TEMPLATE_TEMPLATE_PARM: case TEMPLATE_TYPE_PARM: case TEMPLATE_PARM_INDEX: if (fn && (*fn)(t, data)) return error_mark_node; else if (!fn) return error_mark_node; break; case TEMPLATE_DECL: /* A template template parameter is encountered. */ if (DECL_TEMPLATE_TEMPLATE_PARM_P (t) && for_each_template_parm (TREE_TYPE (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; /* Already substituted template template parameter */ *walk_subtrees = 0; break; case TYPENAME_TYPE: if (!fn || for_each_template_parm (TYPENAME_TYPE_FULLNAME (t), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; break; case CONSTRUCTOR: if (TREE_TYPE (t) && TYPE_PTRMEMFUNC_P (TREE_TYPE (t)) && pfd->include_nondeduced_p && for_each_template_parm (TYPE_PTRMEMFUNC_FN_TYPE (TREE_TYPE (t)), fn, data, pfd->visited, pfd->include_nondeduced_p)) return error_mark_node; break; case INDIRECT_REF: case COMPONENT_REF: /* If there's no type, then this thing must be some expression involving template parameters. */ if (!fn && !TREE_TYPE (t)) return error_mark_node; break; case MODOP_EXPR: case CAST_EXPR: case REINTERPRET_CAST_EXPR: case CONST_CAST_EXPR: case STATIC_CAST_EXPR: case DYNAMIC_CAST_EXPR: case ARROW_EXPR: case DOTSTAR_EXPR: case TYPEID_EXPR: case PSEUDO_DTOR_EXPR: if (!fn) return error_mark_node; break; default: break; } /* We didn't find any template parameters we liked. */ return NULL_TREE; } /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM, BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T, call FN with the parameter and the DATA. If FN returns nonzero, the iteration is terminated, and for_each_template_parm returns 1. Otherwise, the iteration continues. If FN never returns a nonzero value, the value returned by for_each_template_parm is 0. If FN is NULL, it is considered to be the function which always returns 1. If INCLUDE_NONDEDUCED_P, then this routine will also visit template parameters that occur in non-deduced contexts. When false, only visits those template parameters that can be deduced. */ static int for_each_template_parm (tree t, tree_fn_t fn, void* data, struct pointer_set_t *visited, bool include_nondeduced_p) { struct pair_fn_data pfd; int result; /* Set up. */ pfd.fn = fn; pfd.data = data; pfd.include_nondeduced_p = include_nondeduced_p; /* Walk the tree. (Conceptually, we would like to walk without duplicates, but for_each_template_parm_r recursively calls for_each_template_parm, so we would need to reorganize a fair bit to use walk_tree_without_duplicates, so we keep our own visited list.) */ if (visited) pfd.visited = visited; else pfd.visited = pointer_set_create (); result = cp_walk_tree (&t, for_each_template_parm_r, &pfd, pfd.visited) != NULL_TREE; /* Clean up. */ if (!visited) { pointer_set_destroy (pfd.visited); pfd.visited = 0; } return result; } /* Returns true if T depends on any template parameter. */ int uses_template_parms (tree t) { bool dependent_p; int saved_processing_template_decl; saved_processing_template_decl = processing_template_decl; if (!saved_processing_template_decl) processing_template_decl = 1; if (TYPE_P (t)) dependent_p = dependent_type_p (t); else if (TREE_CODE (t) == TREE_VEC) dependent_p = any_dependent_template_arguments_p (t); else if (TREE_CODE (t) == TREE_LIST) dependent_p = (uses_template_parms (TREE_VALUE (t)) || uses_template_parms (TREE_CHAIN (t))); else if (TREE_CODE (t) == TYPE_DECL) dependent_p = dependent_type_p (TREE_TYPE (t)); else if (DECL_P (t) || EXPR_P (t) || TREE_CODE (t) == TEMPLATE_PARM_INDEX || TREE_CODE (t) == OVERLOAD || TREE_CODE (t) == BASELINK || TREE_CODE (t) == IDENTIFIER_NODE || TREE_CODE (t) == TRAIT_EXPR || TREE_CODE (t) == CONSTRUCTOR || CONSTANT_CLASS_P (t)) dependent_p = (type_dependent_expression_p (t) || value_dependent_expression_p (t)); else { gcc_assert (t == error_mark_node); dependent_p = false; } processing_template_decl = saved_processing_template_decl; return dependent_p; } /* Returns true if T depends on any template parameter with level LEVEL. */ int uses_template_parms_level (tree t, int level) { return for_each_template_parm (t, template_parm_this_level_p, &level, NULL, /*include_nondeduced_p=*/true); } static int tinst_depth; extern int max_tinst_depth; #ifdef GATHER_STATISTICS int depth_reached; #endif static int tinst_level_tick; static int last_template_error_tick; /* We're starting to instantiate D; record the template instantiation context for diagnostics and to restore it later. */ int push_tinst_level (tree d) { struct tinst_level *new_level; if (tinst_depth >= max_tinst_depth) { /* If the instantiation in question still has unbound template parms, we don't really care if we can't instantiate it, so just return. This happens with base instantiation for implicit `typename'. */ if (uses_template_parms (d)) return 0; last_template_error_tick = tinst_level_tick; error ("template instantiation depth exceeds maximum of %d (use " "-ftemplate-depth= to increase the maximum) instantiating %qD", max_tinst_depth, d); print_instantiation_context (); return 0; } new_level = GGC_NEW (struct tinst_level); new_level->decl = d; new_level->locus = input_location; new_level->in_system_header_p = in_system_header; new_level->next = current_tinst_level; current_tinst_level = new_level; ++tinst_depth; #ifdef GATHER_STATISTICS if (tinst_depth > depth_reached) depth_reached = tinst_depth; #endif ++tinst_level_tick; return 1; } /* We're done instantiating this template; return to the instantiation context. */ void pop_tinst_level (void) { /* Restore the filename and line number stashed away when we started this instantiation. */ input_location = current_tinst_level->locus; current_tinst_level = current_tinst_level->next; --tinst_depth; ++tinst_level_tick; } /* We're instantiating a deferred template; restore the template instantiation context in which the instantiation was requested, which is one step out from LEVEL. Return the corresponding DECL or TYPE. */ static tree reopen_tinst_level (struct tinst_level *level) { struct tinst_level *t; tinst_depth = 0; for (t = level; t; t = t->next) ++tinst_depth; current_tinst_level = level; pop_tinst_level (); return level->decl; } /* Returns the TINST_LEVEL which gives the original instantiation context. */ struct tinst_level * outermost_tinst_level (void) { struct tinst_level *level = current_tinst_level; if (level) while (level->next) level = level->next; return level; } /* Returns TRUE if PARM is a parameter of the template TEMPL. */ bool parameter_of_template_p (tree parm, tree templ) { tree parms; int i; if (!parm || !templ) return false; gcc_assert (DECL_TEMPLATE_PARM_P (parm)); gcc_assert (TREE_CODE (templ) == TEMPLATE_DECL); parms = DECL_TEMPLATE_PARMS (templ); parms = INNERMOST_TEMPLATE_PARMS (parms); for (i = 0; i < TREE_VEC_LENGTH (parms); ++i) if (parm == TREE_VALUE (TREE_VEC_ELT (parms, i))) return true; return false; } /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the vector of template arguments, as for tsubst. Returns an appropriate tsubst'd friend declaration. */ static tree tsubst_friend_function (tree decl, tree args) { tree new_friend; if (TREE_CODE (decl) == FUNCTION_DECL && DECL_TEMPLATE_INSTANTIATION (decl) && TREE_CODE (DECL_TI_TEMPLATE (decl)) != TEMPLATE_DECL) /* This was a friend declared with an explicit template argument list, e.g.: friend void f<>(T); to indicate that f was a template instantiation, not a new function declaration. Now, we have to figure out what instantiation of what template. */ { tree template_id, arglist, fns; tree new_args; tree tmpl; tree ns = decl_namespace_context (TYPE_MAIN_DECL (current_class_type)); /* Friend functions are looked up in the containing namespace scope. We must enter that scope, to avoid finding member functions of the current class with same name. */ push_nested_namespace (ns); fns = tsubst_expr (DECL_TI_TEMPLATE (decl), args, tf_warning_or_error, NULL_TREE, /*integral_constant_expression_p=*/false); pop_nested_namespace (ns); arglist = tsubst (DECL_TI_ARGS (decl), args, tf_warning_or_error, NULL_TREE); template_id = lookup_template_function (fns, arglist); new_friend = tsubst (decl, args, tf_warning_or_error, NULL_TREE); tmpl = determine_specialization (template_id, new_friend, &new_args, /*need_member_template=*/0, TREE_VEC_LENGTH (args), tsk_none); return instantiate_template (tmpl, new_args, tf_error); } new_friend = tsubst (decl, args, tf_warning_or_error, NULL_TREE); /* The NEW_FRIEND will look like an instantiation, to the compiler, but is not an instantiation from the point of view of the language. For example, we might have had: template <class T> struct S { template <class U> friend void f(T, U); }; Then, in S<int>, template <class U> void f(int, U) is not an instantiation of anything. */ if (new_friend == error_mark_node) return error_mark_node; DECL_USE_TEMPLATE (new_friend) = 0; if (TREE_CODE (decl) == TEMPLATE_DECL) { DECL_USE_TEMPLATE (DECL_TEMPLATE_RESULT (new_friend)) = 0; DECL_SAVED_TREE (DECL_TEMPLATE_RESULT (new_friend)) = DECL_SAVED_TREE (DECL_TEMPLATE_RESULT (decl)); } /* The mangled name for the NEW_FRIEND is incorrect. The function is not a template instantiation and should not be mangled like one. Therefore, we forget the mangling here; we'll recompute it later if we need it. */ if (TREE_CODE (new_friend) != TEMPLATE_DECL) { SET_DECL_RTL (new_friend, NULL_RTX); SET_DECL_ASSEMBLER_NAME (new_friend, NULL_TREE); } if (DECL_NAMESPACE_SCOPE_P (new_friend)) { tree old_decl; tree new_friend_template_info; tree new_friend_result_template_info; tree ns; int new_friend_is_defn; /* We must save some information from NEW_FRIEND before calling duplicate decls since that function will free NEW_FRIEND if possible. */ new_friend_template_info = DECL_TEMPLATE_INFO (new_friend); new_friend_is_defn = (DECL_INITIAL (DECL_TEMPLATE_RESULT (template_for_substitution (new_friend))) != NULL_TREE); if (TREE_CODE (new_friend) == TEMPLATE_DECL) { /* This declaration is a `primary' template. */ DECL_PRIMARY_TEMPLATE (new_friend) = new_friend; new_friend_result_template_info = DECL_TEMPLATE_INFO (DECL_TEMPLATE_RESULT (new_friend)); } else new_friend_result_template_info = NULL_TREE; /* Make the init_value nonzero so pushdecl knows this is a defn. */ if (new_friend_is_defn) DECL_INITIAL (new_friend) = error_mark_node; /* Inside pushdecl_namespace_level, we will push into the current namespace. However, the friend function should go into the namespace of the template. */ ns = decl_namespace_context (new_friend); push_nested_namespace (ns); old_decl = pushdecl_namespace_level (new_friend, /*is_friend=*/true); pop_nested_namespace (ns); if (old_decl == error_mark_node) return error_mark_node; if (old_decl != new_friend) { /* This new friend declaration matched an existing declaration. For example, given: template <class T> void f(T); template <class U> class C { template <class T> friend void f(T) {} }; the friend declaration actually provides the definition of `f', once C has been instantiated for some type. So, old_decl will be the out-of-class template declaration, while new_friend is the in-class definition. But, if `f' was called before this point, the instantiation of `f' will have DECL_TI_ARGS corresponding to `T' but not to `U', references to which might appear in the definition of `f'. Previously, the most general template for an instantiation of `f' was the out-of-class version; now it is the in-class version. Therefore, we run through all specialization of `f', adding to their DECL_TI_ARGS appropriately. In particular, they need a new set of outer arguments, corresponding to the arguments for this class instantiation. The same situation can arise with something like this: friend void f(int); template <class T> class C { friend void f(T) {} }; when `C<int>' is instantiated. Now, `f(int)' is defined in the class. */ if (!new_friend_is_defn) /* On the other hand, if the in-class declaration does *not* provide a definition, then we don't want to alter existing definitions. We can just leave everything alone. */ ; else { tree new_template = TI_TEMPLATE (new_friend_template_info); tree new_args = TI_ARGS (new_friend_template_info); /* Overwrite whatever template info was there before, if any, with the new template information pertaining to the declaration. */ DECL_TEMPLATE_INFO (old_decl) = new_friend_template_info; if (TREE_CODE (old_decl) != TEMPLATE_DECL) /* We should have called reregister_specialization in duplicate_decls. */ gcc_assert (retrieve_specialization (new_template, new_args, 0) == old_decl); else { tree t; /* Indicate that the old function template is a partial instantiation. */ DECL_TEMPLATE_INFO (DECL_TEMPLATE_RESULT (old_decl)) = new_friend_result_template_info; gcc_assert (new_template == most_general_template (new_template)); gcc_assert (new_template != old_decl); /* Reassign any specializations already in the hash table to the new more general template, and add the additional template args. */ for (t = DECL_TEMPLATE_INSTANTIATIONS (old_decl); t != NULL_TREE; t = TREE_CHAIN (t)) { tree spec = TREE_VALUE (t); spec_entry elt; elt.tmpl = old_decl; elt.args = DECL_TI_ARGS (spec); elt.spec = NULL_TREE; htab_remove_elt (decl_specializations, &elt); DECL_TI_ARGS (spec) = add_outermost_template_args (new_args, DECL_TI_ARGS (spec)); register_specialization (spec, new_template, DECL_TI_ARGS (spec), true, 0); } DECL_TEMPLATE_INSTANTIATIONS (old_decl) = NULL_TREE; } } /* The information from NEW_FRIEND has been merged into OLD_DECL by duplicate_decls. */ new_friend = old_decl; } } else { tree context = DECL_CONTEXT (new_friend); bool dependent_p; /* In the code template <class T> class C { template <class U> friend void C1<U>::f (); // case 1 friend void C2<T>::f (); // case 2 }; we only need to make sure CONTEXT is a complete type for case 2. To distinguish between the two cases, we note that CONTEXT of case 1 remains dependent type after tsubst while this isn't true for case 2. */ ++processing_template_decl; dependent_p = dependent_type_p (context); --processing_template_decl; if (!dependent_p && !complete_type_or_else (context, NULL_TREE)) return error_mark_node; if (COMPLETE_TYPE_P (context)) { /* Check to see that the declaration is really present, and, possibly obtain an improved declaration. */ tree fn = check_classfn (context, new_friend, NULL_TREE); if (fn) new_friend = fn; } } return new_friend; } /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of template arguments, as for tsubst. Returns an appropriate tsubst'd friend type or error_mark_node on failure. */ static tree tsubst_friend_class (tree friend_tmpl, tree args) { tree friend_type; tree tmpl; tree context; context = DECL_CONTEXT (friend_tmpl); if (context) { if (TREE_CODE (context) == NAMESPACE_DECL) push_nested_namespace (context); else push_nested_class (tsubst (context, args, tf_none, NULL_TREE)); } /* Look for a class template declaration. We look for hidden names because two friend declarations of the same template are the same. For example, in: struct A { template <typename> friend class F; }; template <typename> struct B { template <typename> friend class F; }; both F templates are the same. */ tmpl = lookup_name_real (DECL_NAME (friend_tmpl), 0, 0, /*block_p=*/true, 0, LOOKUP_COMPLAIN | LOOKUP_HIDDEN); /* But, if we don't find one, it might be because we're in a situation like this: template <class T> struct S { template <class U> friend struct S; }; Here, in the scope of (say) S<int>, `S' is bound to a TYPE_DECL for `S<int>', not the TEMPLATE_DECL. */ if (!tmpl || !DECL_CLASS_TEMPLATE_P (tmpl)) { tmpl = lookup_name_prefer_type (DECL_NAME (friend_tmpl), 1); tmpl = maybe_get_template_decl_from_type_decl (tmpl); } if (tmpl && DECL_CLASS_TEMPLATE_P (tmpl)) { /* The friend template has already been declared. Just check to see that the declarations match, and install any new default parameters. We must tsubst the default parameters, of course. We only need the innermost template parameters because that is all that redeclare_class_template will look at. */ if (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (friend_tmpl)) > TMPL_ARGS_DEPTH (args)) { tree parms; location_t saved_input_location; parms = tsubst_template_parms (DECL_TEMPLATE_PARMS (friend_tmpl), args, tf_warning_or_error); saved_input_location = input_location; input_location = DECL_SOURCE_LOCATION (friend_tmpl); redeclare_class_template (TREE_TYPE (tmpl), parms); input_location = saved_input_location; } friend_type = TREE_TYPE (tmpl); } else { /* The friend template has not already been declared. In this case, the instantiation of the template class will cause the injection of this template into the global scope. */ tmpl = tsubst (friend_tmpl, args, tf_warning_or_error, NULL_TREE); if (tmpl == error_mark_node) return error_mark_node; /* The new TMPL is not an instantiation of anything, so we forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE for the new type because that is supposed to be the corresponding template decl, i.e., TMPL. */ DECL_USE_TEMPLATE (tmpl) = 0; DECL_TEMPLATE_INFO (tmpl) = NULL_TREE; CLASSTYPE_USE_TEMPLATE (TREE_TYPE (tmpl)) = 0; CLASSTYPE_TI_ARGS (TREE_TYPE (tmpl)) = INNERMOST_TEMPLATE_ARGS (CLASSTYPE_TI_ARGS (TREE_TYPE (tmpl))); /* Inject this template into the global scope. */ friend_type = TREE_TYPE (pushdecl_top_level_maybe_friend (tmpl, true)); } if (context) { if (TREE_CODE (context) == NAMESPACE_DECL) pop_nested_namespace (context); else pop_nested_class (); } return friend_type; } /* Returns zero if TYPE cannot be completed later due to circularity. Otherwise returns one. */ static int can_complete_type_without_circularity (tree type) { if (type == NULL_TREE || type == error_mark_node) return 0; else if (COMPLETE_TYPE_P (type)) return 1; else if (TREE_CODE (type) == ARRAY_TYPE && TYPE_DOMAIN (type)) return can_complete_type_without_circularity (TREE_TYPE (type)); else if (CLASS_TYPE_P (type) && TYPE_BEING_DEFINED (TYPE_MAIN_VARIANT (type))) return 0; else return 1; } /* Apply any attributes which had to be deferred until instantiation time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes; ARGS, COMPLAIN, IN_DECL are as tsubst. */ static void apply_late_template_attributes (tree *decl_p, tree attributes, int attr_flags, tree args, tsubst_flags_t complain, tree in_decl) { tree last_dep = NULL_TREE; tree t; tree *p; for (t = attributes; t; t = TREE_CHAIN (t)) if (ATTR_IS_DEPENDENT (t)) { last_dep = t; attributes = copy_list (attributes); break; } if (DECL_P (*decl_p)) { if (TREE_TYPE (*decl_p) == error_mark_node) return; p = &DECL_ATTRIBUTES (*decl_p); } else p = &TYPE_ATTRIBUTES (*decl_p); if (last_dep) { tree late_attrs = NULL_TREE; tree *q = &late_attrs; for (*p = attributes; *p; ) { t = *p; if (ATTR_IS_DEPENDENT (t)) { *p = TREE_CHAIN (t); TREE_CHAIN (t) = NULL_TREE; /* If the first attribute argument is an identifier, don't pass it through tsubst. Attributes like mode, format, cleanup and several target specific attributes expect it unmodified. */ if (TREE_VALUE (t) && TREE_CODE (TREE_VALUE (t)) == TREE_LIST && TREE_VALUE (TREE_VALUE (t)) && (TREE_CODE (TREE_VALUE (TREE_VALUE (t))) == IDENTIFIER_NODE)) { tree chain = tsubst_expr (TREE_CHAIN (TREE_VALUE (t)), args, complain, in_decl, /*integral_constant_expression_p=*/false); if (chain != TREE_CHAIN (TREE_VALUE (t))) TREE_VALUE (t) = tree_cons (NULL_TREE, TREE_VALUE (TREE_VALUE (t)), chain); } else TREE_VALUE (t) = tsubst_expr (TREE_VALUE (t), args, complain, in_decl, /*integral_constant_expression_p=*/false); *q = t; q = &TREE_CHAIN (t); } else p = &TREE_CHAIN (t); } cplus_decl_attributes (decl_p, late_attrs, attr_flags); } } /* Perform (or defer) access check for typedefs that were referenced from within the template TMPL code. This is a subroutine of instantiate_template and instantiate_class_template. TMPL is the template to consider and TARGS is the list of arguments of that template. */ static void perform_typedefs_access_check (tree tmpl, tree targs) { location_t saved_location; int i; qualified_typedef_usage_t *iter; if (!tmpl || (!CLASS_TYPE_P (tmpl) && TREE_CODE (tmpl) != FUNCTION_DECL)) return; saved_location = input_location; for (i = 0; VEC_iterate (qualified_typedef_usage_t, get_types_needing_access_check (tmpl), i, iter); ++i) { tree type_decl = iter->typedef_decl; tree type_scope = iter->context; if (!type_decl || !type_scope || !CLASS_TYPE_P (type_scope)) continue; if (uses_template_parms (type_decl)) type_decl = tsubst (type_decl, targs, tf_error, NULL_TREE); if (uses_template_parms (type_scope)) type_scope = tsubst (type_scope, targs, tf_error, NULL_TREE); /* Make access check error messages point to the location of the use of the typedef. */ input_location = iter->locus; perform_or_defer_access_check (TYPE_BINFO (type_scope), type_decl, type_decl); } input_location = saved_location; } tree instantiate_class_template (tree type) { tree templ, args, pattern, t, member; tree typedecl; tree pbinfo; tree base_list; unsigned int saved_maximum_field_alignment; if (type == error_mark_node) return error_mark_node; if (TYPE_BEING_DEFINED (type) || COMPLETE_TYPE_P (type) || uses_template_parms (type)) return type; /* Figure out which template is being instantiated. */ templ = most_general_template (CLASSTYPE_TI_TEMPLATE (type)); gcc_assert (TREE_CODE (templ) == TEMPLATE_DECL); /* Determine what specialization of the original template to instantiate. */ t = most_specialized_class (type, templ); if (t == error_mark_node) { TYPE_BEING_DEFINED (type) = 1; return error_mark_node; } else if (t) { /* This TYPE is actually an instantiation of a partial specialization. We replace the innermost set of ARGS with the arguments appropriate for substitution. For example, given: template <class T> struct S {}; template <class T> struct S<T*> {}; and supposing that we are instantiating S<int*>, ARGS will presently be {int*} -- but we need {int}. */ pattern = TREE_TYPE (t); args = TREE_PURPOSE (t); } else { pattern = TREE_TYPE (templ); args = CLASSTYPE_TI_ARGS (type); } /* If the template we're instantiating is incomplete, then clearly there's nothing we can do. */ if (!COMPLETE_TYPE_P (pattern)) return type; /* If we've recursively instantiated too many templates, stop. */ if (! push_tinst_level (type)) return type; /* Now we're really doing the instantiation. Mark the type as in the process of being defined. */ TYPE_BEING_DEFINED (type) = 1; /* We may be in the middle of deferred access check. Disable it now. */ push_deferring_access_checks (dk_no_deferred); push_to_top_level (); /* Use #pragma pack from the template context. */ saved_maximum_field_alignment = maximum_field_alignment; maximum_field_alignment = TYPE_PRECISION (pattern); SET_CLASSTYPE_INTERFACE_UNKNOWN (type); /* Set the input location to the most specialized template definition. This is needed if tsubsting causes an error. */ typedecl = TYPE_MAIN_DECL (pattern); input_location = DECL_SOURCE_LOCATION (typedecl); TYPE_HAS_USER_CONSTRUCTOR (type) = TYPE_HAS_USER_CONSTRUCTOR (pattern); TYPE_HAS_NEW_OPERATOR (type) = TYPE_HAS_NEW_OPERATOR (pattern); TYPE_HAS_ARRAY_NEW_OPERATOR (type) = TYPE_HAS_ARRAY_NEW_OPERATOR (pattern); TYPE_GETS_DELETE (type) = TYPE_GETS_DELETE (pattern); TYPE_HAS_ASSIGN_REF (type) = TYPE_HAS_ASSIGN_REF (pattern); TYPE_HAS_CONST_ASSIGN_REF (type) = TYPE_HAS_CONST_ASSIGN_REF (pattern); TYPE_HAS_INIT_REF (type) = TYPE_HAS_INIT_REF (pattern); TYPE_HAS_CONST_INIT_REF (type) = TYPE_HAS_CONST_INIT_REF (pattern); TYPE_HAS_DEFAULT_CONSTRUCTOR (type) = TYPE_HAS_DEFAULT_CONSTRUCTOR (pattern); TYPE_HAS_CONVERSION (type) = TYPE_HAS_CONVERSION (pattern); TYPE_PACKED (type) = TYPE_PACKED (pattern); TYPE_ALIGN (type) = TYPE_ALIGN (pattern); TYPE_USER_ALIGN (type) = TYPE_USER_ALIGN (pattern); TYPE_FOR_JAVA (type) = TYPE_FOR_JAVA (pattern); /* For libjava's JArray<T> */ if (ANON_AGGR_TYPE_P (pattern)) SET_ANON_AGGR_TYPE_P (type); if (CLASSTYPE_VISIBILITY_SPECIFIED (pattern)) { CLASSTYPE_VISIBILITY_SPECIFIED (type) = 1; CLASSTYPE_VISIBILITY (type) = CLASSTYPE_VISIBILITY (pattern); } pbinfo = TYPE_BINFO (pattern); /* We should never instantiate a nested class before its enclosing class; we need to look up the nested class by name before we can instantiate it, and that lookup should instantiate the enclosing class. */ gcc_assert (!DECL_CLASS_SCOPE_P (TYPE_MAIN_DECL (pattern)) || COMPLETE_TYPE_P (TYPE_CONTEXT (type)) || TYPE_BEING_DEFINED (TYPE_CONTEXT (type))); base_list = NULL_TREE; if (BINFO_N_BASE_BINFOS (pbinfo)) { tree pbase_binfo; tree context = TYPE_CONTEXT (type); tree pushed_scope; int i; /* We must enter the scope containing the type, as that is where the accessibility of types named in dependent bases are looked up from. */ pushed_scope = push_scope (context ? context : global_namespace); /* Substitute into each of the bases to determine the actual basetypes. */ for (i = 0; BINFO_BASE_ITERATE (pbinfo, i, pbase_binfo); i++) { tree base; tree access = BINFO_BASE_ACCESS (pbinfo, i); tree expanded_bases = NULL_TREE; int idx, len = 1; if (PACK_EXPANSION_P (BINFO_TYPE (pbase_binfo))) { expanded_bases = tsubst_pack_expansion (BINFO_TYPE (pbase_binfo), args, tf_error, NULL_TREE); if (expanded_bases == error_mark_node) continue; len = TREE_VEC_LENGTH (expanded_bases); } for (idx = 0; idx < len; idx++) { if (expanded_bases) /* Extract the already-expanded base class. */ base = TREE_VEC_ELT (expanded_bases, idx); else /* Substitute to figure out the base class. */ base = tsubst (BINFO_TYPE (pbase_binfo), args, tf_error, NULL_TREE); if (base == error_mark_node) continue; base_list = tree_cons (access, base, base_list); if (BINFO_VIRTUAL_P (pbase_binfo)) TREE_TYPE (base_list) = integer_type_node; } } /* The list is now in reverse order; correct that. */ base_list = nreverse (base_list); if (pushed_scope) pop_scope (pushed_scope); } /* Now call xref_basetypes to set up all the base-class information. */ xref_basetypes (type, base_list); apply_late_template_attributes (&type, TYPE_ATTRIBUTES (pattern), (int) ATTR_FLAG_TYPE_IN_PLACE, args, tf_error, NULL_TREE); /* Now that our base classes are set up, enter the scope of the class, so that name lookups into base classes, etc. will work correctly. This is precisely analogous to what we do in begin_class_definition when defining an ordinary non-template class, except we also need to push the enclosing classes. */ push_nested_class (type); /* Now members are processed in the order of declaration. */ for (member = CLASSTYPE_DECL_LIST (pattern); member; member = TREE_CHAIN (member)) { tree t = TREE_VALUE (member); if (TREE_PURPOSE (member)) { if (TYPE_P (t)) { /* Build new CLASSTYPE_NESTED_UTDS. */ tree newtag; bool class_template_p; class_template_p = (TREE_CODE (t) != ENUMERAL_TYPE && TYPE_LANG_SPECIFIC (t) && CLASSTYPE_IS_TEMPLATE (t)); /* If the member is a class template, then -- even after substitution -- there may be dependent types in the template argument list for the class. We increment PROCESSING_TEMPLATE_DECL so that dependent_type_p, as that function will assume that no types are dependent when outside of a template. */ if (class_template_p) ++processing_template_decl; newtag = tsubst (t, args, tf_error, NULL_TREE); if (class_template_p) --processing_template_decl; if (newtag == error_mark_node) continue; if (TREE_CODE (newtag) != ENUMERAL_TYPE) { tree name = TYPE_IDENTIFIER (t); if (class_template_p) /* Unfortunately, lookup_template_class sets CLASSTYPE_IMPLICIT_INSTANTIATION for a partial instantiation (i.e., for the type of a member template class nested within a template class.) This behavior is required for maybe_process_partial_specialization to work correctly, but is not accurate in this case; the TAG is not an instantiation of anything. (The corresponding TEMPLATE_DECL is an instantiation, but the TYPE is not.) */ CLASSTYPE_USE_TEMPLATE (newtag) = 0; /* Now, we call pushtag to put this NEWTAG into the scope of TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid pushtag calling push_template_decl. We don't have to do this for enums because it will already have been done in tsubst_enum. */ if (name) SET_IDENTIFIER_TYPE_VALUE (name, newtag); pushtag (name, newtag, /*tag_scope=*/ts_current); } } else if (TREE_CODE (t) == FUNCTION_DECL || DECL_FUNCTION_TEMPLATE_P (t)) { /* Build new TYPE_METHODS. */ tree r; if (TREE_CODE (t) == TEMPLATE_DECL) ++processing_template_decl; r = tsubst (t, args, tf_error, NULL_TREE); if (TREE_CODE (t) == TEMPLATE_DECL) --processing_template_decl; set_current_access_from_decl (r); finish_member_declaration (r); } else { /* Build new TYPE_FIELDS. */ if (TREE_CODE (t) == STATIC_ASSERT) { tree condition = tsubst_expr (STATIC_ASSERT_CONDITION (t), args, tf_warning_or_error, NULL_TREE, /*integral_constant_expression_p=*/true); finish_static_assert (condition, STATIC_ASSERT_MESSAGE (t), STATIC_ASSERT_SOURCE_LOCATION (t), /*member_p=*/true); } else if (TREE_CODE (t) != CONST_DECL) { tree r; /* The file and line for this declaration, to assist in error message reporting. Since we called push_tinst_level above, we don't need to restore these. */ input_location = DECL_SOURCE_LOCATION (t); if (TREE_CODE (t) == TEMPLATE_DECL) ++processing_template_decl; r = tsubst (t, args, tf_warning_or_error, NULL_TREE); if (TREE_CODE (t) == TEMPLATE_DECL) --processing_template_decl; if (TREE_CODE (r) == VAR_DECL) { /* In [temp.inst]: [t]he initialization (and any associated side-effects) of a static data member does not occur unless the static data member is itself used in a way that requires the definition of the static data member to exist. Therefore, we do not substitute into the initialized for the static data member here. */ finish_static_data_member_decl (r, /*init=*/NULL_TREE, /*init_const_expr_p=*/false, /*asmspec_tree=*/NULL_TREE, /*flags=*/0); if (DECL_INITIALIZED_IN_CLASS_P (r)) check_static_variable_definition (r, TREE_TYPE (r)); } else if (TREE_CODE (r) == FIELD_DECL) { /* Determine whether R has a valid type and can be completed later. If R is invalid, then it is replaced by error_mark_node so that it will not be added to TYPE_FIELDS. */ tree rtype = TREE_TYPE (r); if (can_complete_type_without_circularity (rtype)) complete_type (rtype); if (!COMPLETE_TYPE_P (rtype)) { cxx_incomplete_type_error (r, rtype); r = error_mark_node; } } /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE, such a thing will already have been added to the field list by tsubst_enum in finish_member_declaration in the CLASSTYPE_NESTED_UTDS case above. */ if (!(TREE_CODE (r) == TYPE_DECL && TREE_CODE (TREE_TYPE (r)) == ENUMERAL_TYPE && DECL_ARTIFICIAL (r))) { set_current_access_from_decl (r); finish_member_declaration (r); } } } } else { if (TYPE_P (t) || DECL_CLASS_TEMPLATE_P (t)) { /* Build new CLASSTYPE_FRIEND_CLASSES. */ tree friend_type = t; bool adjust_processing_template_decl = false; if (TREE_CODE (friend_type) == TEMPLATE_DECL) { /* template <class T> friend class C; */ friend_type = tsubst_friend_class (friend_type, args); adjust_processing_template_decl = true; } else if (TREE_CODE (friend_type) == UNBOUND_CLASS_TEMPLATE) { /* template <class T> friend class C::D; */ friend_type = tsubst (friend_type, args, tf_warning_or_error, NULL_TREE); if (TREE_CODE (friend_type) == TEMPLATE_DECL) friend_type = TREE_TYPE (friend_type); adjust_processing_template_decl = true; } else if (TREE_CODE (friend_type) == TYPENAME_TYPE) { /* This could be either friend class T::C; when dependent_type_p is false or template <class U> friend class T::C; otherwise. */ friend_type = tsubst (friend_type, args, tf_warning_or_error, NULL_TREE); /* Bump processing_template_decl for correct dependent_type_p calculation. */ ++processing_template_decl; if (dependent_type_p (friend_type)) adjust_processing_template_decl = true; --processing_template_decl; } else if (!CLASSTYPE_USE_TEMPLATE (friend_type) && hidden_name_p (TYPE_NAME (friend_type))) { /* friend class C; where C hasn't been declared yet. Let's lookup name from namespace scope directly, bypassing any name that come from dependent base class. */ tree ns = decl_namespace_context (TYPE_MAIN_DECL (friend_type)); /* The call to xref_tag_from_type does injection for friend classes. */ push_nested_namespace (ns); friend_type = xref_tag_from_type (friend_type, NULL_TREE, /*tag_scope=*/ts_current); pop_nested_namespace (ns); } else if (uses_template_parms (friend_type)) /* friend class C<T>; */ friend_type = tsubst (friend_type, args, tf_warning_or_error, NULL_TREE); /* Otherwise it's friend class C; where C is already declared or friend class C<int>; We don't have to do anything in these cases. */ if (adjust_processing_template_decl) /* Trick make_friend_class into realizing that the friend we're adding is a template, not an ordinary class. It's important that we use make_friend_class since it will perform some error-checking and output cross-reference information. */ ++processing_template_decl; if (friend_type != error_mark_node) make_friend_class (type, friend_type, /*complain=*/false); if (adjust_processing_template_decl) --processing_template_decl; } else { /* Build new DECL_FRIENDLIST. */ tree r; /* The file and line for this declaration, to assist in error message reporting. Since we called push_tinst_level above, we don't need to restore these. */ input_location = DECL_SOURCE_LOCATION (t); if (TREE_CODE (t) == TEMPLATE_DECL) { ++processing_template_decl; push_deferring_access_checks (dk_no_check); } r = tsubst_friend_function (t, args); add_friend (type, r, /*complain=*/false); if (TREE_CODE (t) == TEMPLATE_DECL) { pop_deferring_access_checks (); --processing_template_decl; } } } } /* Set the file and line number information to whatever is given for the class itself. This puts error messages involving generated implicit functions at a predictable point, and the same point that would be used for non-template classes. */ input_location = DECL_SOURCE_LOCATION (typedecl); unreverse_member_declarations (type); finish_struct_1 (type); TYPE_BEING_DEFINED (type) = 0; /* Now that the class is complete, instantiate default arguments for any member functions. We don't do this earlier because the default arguments may reference members of the class. */ if (!PRIMARY_TEMPLATE_P (templ)) for (t = TYPE_METHODS (type); t; t = TREE_CHAIN (t)) if (TREE_CODE (t) == FUNCTION_DECL /* Implicitly generated member functions will not have template information; they are not instantiations, but instead are created "fresh" for each instantiation. */ && DECL_TEMPLATE_INFO (t)) tsubst_default_arguments (t); /* Some typedefs referenced from within the template code need to be access checked at template instantiation time, i.e now. These types were added to the template at parsing time. Let's get those and perform the access checks then. */ perform_typedefs_access_check (pattern, args); perform_deferred_access_checks (); pop_nested_class (); maximum_field_alignment = saved_maximum_field_alignment; pop_from_top_level (); pop_deferring_access_checks (); pop_tinst_level (); /* The vtable for a template class can be emitted in any translation unit in which the class is instantiated. When there is no key method, however, finish_struct_1 will already have added TYPE to the keyed_classes list. */ if (TYPE_CONTAINS_VPTR_P (type) && CLASSTYPE_KEY_METHOD (type)) keyed_classes = tree_cons (NULL_TREE, type, keyed_classes); return type; } static tree tsubst_template_arg (tree t, tree args, tsubst_flags_t complain, tree in_decl) { tree r; if (!t) r = t; else if (TYPE_P (t)) r = tsubst (t, args, complain, in_decl); else { r = tsubst_expr (t, args, complain, in_decl, /*integral_constant_expression_p=*/true); r = fold_non_dependent_expr (r); } return r; } /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a NONTYPE_ARGUMENT_PACK. */ static tree make_fnparm_pack (tree spec_parm) { /* Collect all of the extra "packed" parameters into an argument pack. */ tree parmvec; tree parmtypevec; tree argpack = make_node (NONTYPE_ARGUMENT_PACK); tree argtypepack = cxx_make_type (TYPE_ARGUMENT_PACK); int i, len = list_length (spec_parm); /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */ parmvec = make_tree_vec (len); parmtypevec = make_tree_vec (len); for (i = 0; i < len; i++, spec_parm = TREE_CHAIN (spec_parm)) { TREE_VEC_ELT (parmvec, i) = spec_parm; TREE_VEC_ELT (parmtypevec, i) = TREE_TYPE (spec_parm); } /* Build the argument packs. */ SET_ARGUMENT_PACK_ARGS (argpack, parmvec); SET_ARGUMENT_PACK_ARGS (argtypepack, parmtypevec); TREE_TYPE (argpack) = argtypepack; return argpack; } /* Substitute ARGS into T, which is an pack expansion (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node (if only a partial substitution could be performed) or ERROR_MARK_NODE if there was an error. */ tree tsubst_pack_expansion (tree t, tree args, tsubst_flags_t complain, tree in_decl) { tree pattern; tree pack, packs = NULL_TREE, unsubstituted_packs = NULL_TREE; int i, len = -1; tree result; int incomplete = 0; htab_t saved_local_specializations = NULL; gcc_assert (PACK_EXPANSION_P (t)); pattern = PACK_EXPANSION_PATTERN (t); /* Determine the argument packs that will instantiate the parameter packs used in the expansion expression. While we're at it, compute the number of arguments to be expanded and make sure it is consistent. */ for (pack = PACK_EXPANSION_PARAMETER_PACKS (t); pack; pack = TREE_CHAIN (pack)) { tree parm_pack = TREE_VALUE (pack); tree arg_pack = NULL_TREE; tree orig_arg = NULL_TREE; if (TREE_CODE (parm_pack) == PARM_DECL) { if (!cp_unevaluated_operand) arg_pack = retrieve_local_specialization (parm_pack); else { /* We can't rely on local_specializations for a parameter name used later in a function declaration (such as in a late-specified return type). Even if it exists, it might have the wrong value for a recursive call. Just make a dummy decl, since it's only used for its type. */ arg_pack = tsubst_decl (parm_pack, args, complain); arg_pack = make_fnparm_pack (arg_pack); } } else { int level, idx, levels; template_parm_level_and_index (parm_pack, &level, &idx); levels = TMPL_ARGS_DEPTH (args); if (level <= levels) arg_pack = TMPL_ARG (args, level, idx); } orig_arg = arg_pack; if (arg_pack && TREE_CODE (arg_pack) == ARGUMENT_PACK_SELECT) arg_pack = ARGUMENT_PACK_SELECT_FROM_PACK (arg_pack); if (arg_pack && !ARGUMENT_PACK_P (arg_pack)) /* This can only happen if we forget to expand an argument pack somewhere else. Just return an error, silently. */ { result = make_tree_vec (1); TREE_VEC_ELT (result, 0) = error_mark_node; return result; } if (arg_pack && TREE_VEC_LENGTH (ARGUMENT_PACK_ARGS (arg_pack)) == 1 && PACK_EXPANSION_P (TREE_VEC_ELT (ARGUMENT_PACK_ARGS (arg_pack), 0))) { tree expansion = TREE_VEC_ELT (ARGUMENT_PACK_ARGS (arg_pack), 0); tree pattern = PACK_EXPANSION_PATTERN (expansion); if ((TYPE_P (pattern) && same_type_p (pattern, parm_pack)) || (!TYPE_P (pattern) && cp_tree_equal (parm_pack, pattern))) /* The argument pack that the parameter maps to is just an expansion of the parameter itself, such as one would find in the implicit typedef of a class inside the class itself. Consider this parameter "unsubstituted", so that we will maintain the outer pack expansion. */ arg_pack = NULL_TREE; } if (arg_pack) { int my_len = TREE_VEC_LENGTH (ARGUMENT_PACK_ARGS (arg_pack)); /* It's all-or-nothing with incomplete argument packs. */ if (incomplete && !ARGUMENT_PACK_INCOMPLETE_P (arg_pack)) return error_mark_node; if (ARGUMENT_PACK_INCOMPLETE_P (arg_pack)) incomplete = 1; if (len < 0) len = my_len; else if (len != my_len) { if (incomplete) /* We got explicit args for some packs but not others; do nothing now and try again after deduction. */ return t; if (TREE_CODE (t) == TYPE_PACK_EXPANSION) error ("mismatched argument pack lengths while expanding " "%<%T%>", pattern); else error ("mismatched argument pack lengths while expanding " "%<%E%>", pattern); return error_mark_node; } /* Keep track of the parameter packs and their corresponding argument packs. */ packs = tree_cons (parm_pack, arg_pack, packs); TREE_TYPE (packs) = orig_arg; } else /* We can't substitute for this parameter pack. */ unsubstituted_packs = tree_cons (TREE_PURPOSE (pack), TREE_VALUE (pack), unsubstituted_packs); } /* We cannot expand this expansion expression, because we don't have all of the argument packs we need. Substitute into the pattern and return a PACK_EXPANSION_*. The caller will need to deal with that. */ if (unsubstituted_packs) { tree new_pat; if (TREE_CODE (t) == EXPR_PACK_EXPANSION) new_pat = tsubst_expr (pattern, args, complain, in_decl, /*integral_constant_expression_p=*/false); else new_pat = tsubst (pattern, args, complain, in_decl); return make_pack_expansion (new_pat); } /* We could not find any argument packs that work. */ if (len < 0) return error_mark_node; if (cp_unevaluated_operand) { /* We're in a late-specified return type, so create our own local specializations table; the current table is either NULL or (in the case of recursive unification) might have bindings that we don't want to use or alter. */ saved_local_specializations = local_specializations; local_specializations = htab_create (37, hash_local_specialization, eq_local_specializations, NULL); } /* For each argument in each argument pack, substitute into the pattern. */ result = make_tree_vec (len + incomplete); for (i = 0; i < len + incomplete; ++i) { /* For parameter pack, change the substitution of the parameter pack to the ith argument in its argument pack, then expand the pattern. */ for (pack = packs; pack; pack = TREE_CHAIN (pack)) { tree parm = TREE_PURPOSE (pack); if (TREE_CODE (parm) == PARM_DECL) { /* Select the Ith argument from the pack. */ tree arg = make_node (ARGUMENT_PACK_SELECT); ARGUMENT_PACK_SELECT_FROM_PACK (arg) = TREE_VALUE (pack); ARGUMENT_PACK_SELECT_INDEX (arg) = i; mark_used (parm); register_local_specialization (arg, parm); } else { tree value = parm; int idx, level; template_parm_level_and_index (parm, &level, &idx); if (i < len) { /* Select the Ith argument from the pack. */ value = make_node (ARGUMENT_PACK_SELECT); ARGUMENT_PACK_SELECT_FROM_PACK (value) = TREE_VALUE (pack); ARGUMENT_PACK_SELECT_INDEX (value) = i; } /* Update the corresponding argument. */ TMPL_ARG (args, level, idx) = value; } } /* Substitute into the PATTERN with the altered arguments. */ if (TREE_CODE (t) == EXPR_PACK_EXPANSION) TREE_VEC_ELT (result, i) = tsubst_expr (pattern, args, complain, in_decl, /*integral_constant_expression_p=*/false); else TREE_VEC_ELT (result, i) = tsubst (pattern, args, complain, in_decl); if (i == len) /* When we have incomplete argument packs, the last "expanded" result is itself a pack expansion, which allows us to deduce more arguments. */ TREE_VEC_ELT (result, i) = make_pack_expansion (TREE_VEC_ELT (result, i)); if (TREE_VEC_ELT (result, i) == error_mark_node) { result = error_mark_node; break; } } /* Update ARGS to restore the substitution from parameter packs to their argument packs. */ for (pack = packs; pack; pack = TREE_CHAIN (pack)) { tree parm = TREE_PURPOSE (pack); if (TREE_CODE (parm) == PARM_DECL) register_local_specialization (TREE_TYPE (pack), parm); else { int idx, level; template_parm_level_and_index (parm, &level, &idx); /* Update the corresponding argument. */ if (TMPL_ARGS_HAVE_MULTIPLE_LEVELS (args)) TREE_VEC_ELT (TREE_VEC_ELT (args, level -1 ), idx) = TREE_TYPE (pack); else TREE_VEC_ELT (args, idx) = TREE_TYPE (pack); } } if (saved_local_specializations) { htab_delete (local_specializations); local_specializations = saved_local_specializations; } return result; } /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template TMPL. We do this using DECL_PARM_INDEX, which should work even with parameter packs; all parms generated from a function parameter pack will have the same DECL_PARM_INDEX. */ tree get_pattern_parm (tree parm, tree tmpl) { tree pattern = DECL_TEMPLATE_RESULT (tmpl); tree patparm; if (DECL_ARTIFICIAL (parm)) { for (patparm = DECL_ARGUMENTS (pattern); patparm; patparm = TREE_CHAIN (patparm)) if (DECL_ARTIFICIAL (patparm) && DECL_NAME (parm) == DECL_NAME (patparm)) break; } else { patparm = FUNCTION_FIRST_USER_PARM (DECL_TEMPLATE_RESULT (tmpl)); patparm = chain_index (DECL_PARM_INDEX (parm)-1, patparm); gcc_assert (DECL_PARM_INDEX (patparm) == DECL_PARM_INDEX (parm)); } return patparm; } /* Substitute ARGS into the vector or list of template arguments T. */ static tree tsubst_template_args (tree t, tree args, tsubst_flags_t complain, tree in_decl) { tree orig_t = t; int len = TREE_VEC_LENGTH (t); int need_new = 0, i, expanded_len_adjust = 0, out; tree *elts = (tree *) alloca (len * sizeof (tree)); for (i = 0; i < len; i++) { tree orig_arg = TREE_VEC_ELT (t, i); tree new_arg; if (TREE_CODE (orig_arg) == TREE_VEC) new_arg = tsubst_template_args (orig_arg, args, complain, in_decl); else if (PACK_EXPANSION_P (orig_arg)) { /* Substitute into an expansion expression. */ new_arg = tsubst_pack_expansion (orig_arg, args, complain, in_decl); if (TREE_CODE (new_arg) == TREE_VEC) /* Add to the expanded length adjustment the number of expanded arguments. We subtract one from this measurement, because the argument pack expression itself is already counted as 1 in LEN. EXPANDED_LEN_ADJUST can actually be negative, if the argument pack is empty. */ expanded_len_adjust += TREE_VEC_LENGTH (new_arg) - 1; } else if (ARGUMENT_PACK_P (orig_arg)) { /* Substitute into each of the arguments. */ new_arg = TYPE_P (orig_arg) ? cxx_make_type (TREE_CODE (orig_arg)) : make_node (TREE_CODE (orig_arg)); SET_ARGUMENT_PACK_ARGS ( new_arg, tsubst_template_args (ARGUMENT_PACK_ARGS (orig_arg), args, complain, in_decl)); if (ARGUMENT_PACK_ARGS (new_arg) == error_mark_node) new_arg = error_mark_node; if (TREE_CODE (new_arg) == NONTYPE_ARGUMENT_PACK) { TREE_TYPE (new_arg) = tsubst (TREE_TYPE (orig_arg), args, complain, in_decl); TREE_CONSTANT (new_arg) = TREE_CONSTANT (orig_arg); if (TREE_TYPE (new_arg) == error_mark_node) new_arg = error_mark_node; } } else new_arg = tsubst_template_arg (orig_arg, args, complain, in_decl); if (new_arg == error_mark_node) return error_mark_node; elts[i] = new_arg; if (new_arg != orig_arg) need_new = 1; } if (!need_new) return t; /* Make space for the expanded arguments coming from template argument packs. */ t = make_tree_vec (len + expanded_len_adjust); /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the arguments for a member template. In that case each TREE_VEC in ORIG_T represents a level of template arguments, and ORIG_T won't carry any non defaulted argument count. It will rather be the nested TREE_VECs that will carry one. In other words, ORIG_T carries a non defaulted argument count only if it doesn't contain any nested TREE_VEC. */ if (NON_DEFAULT_TEMPLATE_ARGS_COUNT (orig_t)) { int count = GET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (orig_t); count += expanded_len_adjust; SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (t, count); } for (i = 0, out = 0; i < len; i++) { if ((PACK_EXPANSION_P (TREE_VEC_ELT (orig_t, i)) || ARGUMENT_PACK_P (TREE_VEC_ELT (orig_t, i))) && TREE_CODE (elts[i]) == TREE_VEC) { int idx; /* Now expand the template argument pack "in place". */ for (idx = 0; idx < TREE_VEC_LENGTH (elts[i]); idx++, out++) TREE_VEC_ELT (t, out) = TREE_VEC_ELT (elts[i], idx); } else { TREE_VEC_ELT (t, out) = elts[i]; out++; } } return t; } /* Return the result of substituting ARGS into the template parameters given by PARMS. If there are m levels of ARGS and m + n levels of PARMS, then the result will contain n levels of PARMS. For example, if PARMS is `template <class T> template <class U> template <T*, U, class V>' and ARGS is {{int}, {double}} then the result will be `template <int*, double, class V>'. */ static tree tsubst_template_parms (tree parms, tree args, tsubst_flags_t complain) { tree r = NULL_TREE; tree* new_parms; /* When substituting into a template, we must set PROCESSING_TEMPLATE_DECL as the template parameters may be dependent if they are based on one-another, and the dependency predicates are short-circuit outside of templates. */ ++processing_template_decl; for (new_parms = &r; TMPL_PARMS_DEPTH (parms) > TMPL_ARGS_DEPTH (args); new_parms = &(TREE_CHAIN (*new_parms)), parms = TREE_CHAIN (parms)) { tree new_vec = make_tree_vec (TREE_VEC_LENGTH (TREE_VALUE (parms))); int i; for (i = 0; i < TREE_VEC_LENGTH (new_vec); ++i) { tree tuple; tree default_value; tree parm_decl; if (parms == error_mark_node) continue; tuple = TREE_VEC_ELT (TREE_VALUE (parms), i); if (tuple == error_mark_node) continue; default_value = TREE_PURPOSE (tuple); parm_decl = TREE_VALUE (tuple); parm_decl = tsubst (parm_decl, args, complain, NULL_TREE); if (TREE_CODE (parm_decl) == PARM_DECL && invalid_nontype_parm_type_p (TREE_TYPE (parm_decl), complain)) parm_decl = error_mark_node; default_value = tsubst_template_arg (default_value, args, complain, NULL_TREE); tuple = build_tree_list (default_value, parm_decl); TREE_VEC_ELT (new_vec, i) = tuple; } *new_parms = tree_cons (size_int (TMPL_PARMS_DEPTH (parms) - TMPL_ARGS_DEPTH (args)), new_vec, NULL_TREE); } --processing_template_decl; return r; } /* Substitute the ARGS into the indicated aggregate (or enumeration) type T. If T is not an aggregate or enumeration type, it is handled as if by tsubst. IN_DECL is as for tsubst. If ENTERING_SCOPE is nonzero, T is the context for a template which we are presently tsubst'ing. Return the substituted value. */ static tree tsubst_aggr_type (tree t, tree args, tsubst_flags_t complain, tree in_decl, int entering_scope) { if (t == NULL_TREE) return NULL_TREE; switch (TREE_CODE (t)) { case RECORD_TYPE: if (TYPE_PTRMEMFUNC_P (t)) return tsubst (TYPE_PTRMEMFUNC_FN_TYPE (t), args, complain, in_decl); /* Else fall through. */ case ENUMERAL_TYPE: case UNION_TYPE: if (TYPE_TEMPLATE_INFO (t) && uses_template_parms (t)) { tree argvec; tree context; tree r; int saved_unevaluated_operand; int saved_inhibit_evaluation_warnings; /* In "sizeof(X<I>)" we need to evaluate "I". */ saved_unevaluated_operand = cp_unevaluated_operand; cp_unevaluated_operand = 0; saved_inhibit_evaluation_warnings = c_inhibit_evaluation_warnings; c_inhibit_evaluation_warnings = 0; /* First, determine the context for the type we are looking up. */ context = TYPE_CONTEXT (t); if (context) { context = tsubst_aggr_type (context, args, complain, in_decl, /*entering_scope=*/1); /* If context is a nested class inside a class template, it may still need to be instantiated (c++/33959). */ if (TYPE_P (context)) context = complete_type (context); } /* Then, figure out what arguments are appropriate for the type we are trying to find. For example, given: template <class T> struct S; template <class T, class U> void f(T, U) { S<U> su; } and supposing that we are instantiating f<int, double>, then our ARGS will be {int, double}, but, when looking up S we only want {double}. */ argvec = tsubst_template_args (TYPE_TI_ARGS (t), args, complain, in_decl); if (argvec == error_mark_node) r = error_mark_node; else { r = lookup_template_class (t, argvec, in_decl, context, entering_scope, complain); r = cp_build_qualified_type_real (r, TYPE_QUALS (t), complain); } cp_unevaluated_operand = saved_unevaluated_operand; c_inhibit_evaluation_warnings = saved_inhibit_evaluation_warnings; return r; } else /* This is not a template type, so there's nothing to do. */ return t; default: return tsubst (t, args, complain, in_decl); } } /* Substitute into the default argument ARG (a default argument for FN), which has the indicated TYPE. */ tree tsubst_default_argument (tree fn, tree type, tree arg) { tree saved_class_ptr = NULL_TREE; tree saved_class_ref = NULL_TREE; /* This default argument came from a template. Instantiate the default argument here, not in tsubst. In the case of something like: template <class T> struct S { static T t(); void f(T = t()); }; we must be careful to do name lookup in the scope of S<T>, rather than in the current class. */ push_access_scope (fn); /* The "this" pointer is not valid in a default argument. */ if (cfun) { saved_class_ptr = current_class_ptr; cp_function_chain->x_current_class_ptr = NULL_TREE; saved_class_ref = current_class_ref; cp_function_chain->x_current_class_ref = NULL_TREE; } push_deferring_access_checks(dk_no_deferred); /* The default argument expression may cause implicitly defined member functions to be synthesized, which will result in garbage collection. We must treat this situation as if we were within the body of function so as to avoid collecting live data on the stack. */ ++function_depth; arg = tsubst_expr (arg, DECL_TI_ARGS (fn), tf_warning_or_error, NULL_TREE, /*integral_constant_expression_p=*/false); --function_depth; pop_deferring_access_checks(); /* Restore the "this" pointer. */ if (cfun) { cp_function_chain->x_current_class_ptr = saved_class_ptr; cp_function_chain->x_current_class_ref = saved_class_ref; } /* Make sure the default argument is reasonable. */ arg = check_default_argument (type, arg); pop_access_scope (fn); return arg; } /* Substitute into all the default arguments for FN. */ static void tsubst_default_arguments (tree fn) { tree arg; tree tmpl_args; tmpl_args = DECL_TI_ARGS (fn); /* If this function is not yet instantiated, we certainly don't need its default arguments. */ if (uses_template_parms (tmpl_args)) return; for (arg = TYPE_ARG_TYPES (TREE_TYPE (fn)); arg; arg = TREE_CHAIN (arg)) if (TREE_PURPOSE (arg)) TREE_PURPOSE (arg) = tsubst_default_argument (fn, TREE_VALUE (arg), TREE_PURPOSE (arg)); } /* Substitute the ARGS into the T, which is a _DECL. Return the result of the substitution. Issue error and warning messages under control of COMPLAIN. */ static tree tsubst_decl (tree t, tree args, tsubst_flags_t complain) { #define RETURN(EXP) do { r = (EXP); goto out; } while(0) location_t saved_loc; tree r = NULL_TREE; tree in_decl = t; hashval_t hash = 0; /* Set the filename and linenumber to improve error-reporting. */ saved_loc = input_location; input_location = DECL_SOURCE_LOCATION (t); switch (TREE_CODE (t)) { case TEMPLATE_DECL: { /* We can get here when processing a member function template, member class template, or template template parameter. */ tree decl = DECL_TEMPLATE_RESULT (t); tree spec; tree tmpl_args; tree full_args; if (DECL_TEMPLATE_TEMPLATE_PARM_P (t)) { /* Template template parameter is treated here. */ tree new_type = tsubst (TREE_TYPE (t), args, complain, in_decl); if (new_type == error_mark_node) RETURN (error_mark_node); r = copy_decl (t); TREE_CHAIN (r) = NULL_TREE; TREE_TYPE (r) = new_type; DECL_TEMPLATE_RESULT (r) = build_decl (DECL_SOURCE_LOCATION (decl), TYPE_DECL, DECL_NAME (decl), new_type); DECL_TEMPLATE_PARMS (r) = tsubst_template_parms (DECL_TEMPLATE_PARMS (t), args, complain); TYPE_NAME (new_type) = r; break; } /* We might already have an instance of this template. The ARGS are for the surrounding class type, so the full args contain the tsubst'd args for the context, plus the innermost args from the template decl. */ tmpl_args = DECL_CLASS_TEMPLATE_P (t) ? CLASSTYPE_TI_ARGS (TREE_TYPE (t)) : DECL_TI_ARGS (DECL_TEMPLATE_RESULT (t)); /* Because this is a template, the arguments will still be dependent, even after substitution. If PROCESSING_TEMPLATE_DECL is not set, the dependency predicates will short-circuit. */ ++processing_template_decl; full_args = tsubst_template_args (tmpl_args, args, complain, in_decl); --processing_template_decl; if (full_args == error_mark_node) RETURN (error_mark_node); /* If this is a default template template argument, tsubst might not have changed anything. */ if (full_args == tmpl_args) RETURN (t); hash = hash_tmpl_and_args (t, full_args); spec = retrieve_specialization (t, full_args, hash); if (spec != NULL_TREE) { r = spec; break; } /* Make a new template decl. It will be similar to the original, but will record the current template arguments. We also create a new function declaration, which is just like the old one, but points to this new template, rather than the old one. */ r = copy_decl (t); gcc_assert (DECL_LANG_SPECIFIC (r) != 0); TREE_CHAIN (r) = NULL_TREE; DECL_TEMPLATE_INFO (r) = build_template_info (t, args); if (TREE_CODE (decl) == TYPE_DECL) { tree new_type; ++processing_template_decl; new_type = tsubst (TREE_TYPE (t), args, complain, in_decl); --processing_template_decl; if (new_type == error_mark_node) RETURN (error_mark_node); TREE_TYPE (r) = new_type; CLASSTYPE_TI_TEMPLATE (new_type) = r; DECL_TEMPLATE_RESULT (r) = TYPE_MAIN_DECL (new_type); DECL_TI_ARGS (r) = CLASSTYPE_TI_ARGS (new_type); DECL_CONTEXT (r) = TYPE_CONTEXT (new_type); } else { tree new_decl; ++processing_template_decl; new_decl = tsubst (decl, args, complain, in_decl); --processing_template_decl; if (new_decl == error_mark_node) RETURN (error_mark_node); DECL_TEMPLATE_RESULT (r) = new_decl; DECL_TI_TEMPLATE (new_decl) = r; TREE_TYPE (r) = TREE_TYPE (new_decl); DECL_TI_ARGS (r) = DECL_TI_ARGS (new_decl); DECL_CONTEXT (r) = DECL_CONTEXT (new_decl); } SET_DECL_IMPLICIT_INSTANTIATION (r); DECL_TEMPLATE_INSTANTIATIONS (r) = NULL_TREE; DECL_TEMPLATE_SPECIALIZATIONS (r) = NULL_TREE; /* The template parameters for this new template are all the template parameters for the old template, except the outermost level of parameters. */ DECL_TEMPLATE_PARMS (r) = tsubst_template_parms (DECL_TEMPLATE_PARMS (t), args, complain); if (PRIMARY_TEMPLATE_P (t)) DECL_PRIMARY_TEMPLATE (r) = r; if (TREE_CODE (decl) != TYPE_DECL) /* Record this non-type partial instantiation. */ register_specialization (r, t, DECL_TI_ARGS (DECL_TEMPLATE_RESULT (r)), false, hash); } break; case FUNCTION_DECL: { tree ctx; tree argvec = NULL_TREE; tree *friends; tree gen_tmpl; tree type; int member; int args_depth; int parms_depth; /* Nobody should be tsubst'ing into non-template functions. */ gcc_assert (DECL_TEMPLATE_INFO (t) != NULL_TREE); if (TREE_CODE (DECL_TI_TEMPLATE (t)) == TEMPLATE_DECL) { tree spec; bool dependent_p; /* If T is not dependent, just return it. We have to increment PROCESSING_TEMPLATE_DECL because value_dependent_expression_p assumes that nothing is dependent when PROCESSING_TEMPLATE_DECL is zero. */ ++processing_template_decl; dependent_p = value_dependent_expression_p (t); --processing_template_decl; if (!dependent_p) RETURN (t); /* Calculate the most general template of which R is a specialization, and the complete set of arguments used to specialize R. */ gen_tmpl = most_general_template (DECL_TI_TEMPLATE (t)); argvec = tsubst_template_args (DECL_TI_ARGS (DECL_TEMPLATE_RESULT (gen_tmpl)), args, complain, in_decl); /* Check to see if we already have this specialization. */ hash = hash_tmpl_and_args (gen_tmpl, argvec); spec = retrieve_specialization (gen_tmpl, argvec, hash); if (spec) { r = spec; break; } /* We can see more levels of arguments than parameters if there was a specialization of a member template, like this: template <class T> struct S { template <class U> void f(); } template <> template <class U> void S<int>::f(U); Here, we'll be substituting into the specialization, because that's where we can find the code we actually want to generate, but we'll have enough arguments for the most general template. We also deal with the peculiar case: template <class T> struct S { template <class U> friend void f(); }; template <class U> void f() {} template S<int>; template void f<double>(); Here, the ARGS for the instantiation of will be {int, double}. But, we only need as many ARGS as there are levels of template parameters in CODE_PATTERN. We are careful not to get fooled into reducing the ARGS in situations like: template <class T> struct S { template <class U> void f(U); } template <class T> template <> void S<T>::f(int) {} which we can spot because the pattern will be a specialization in this case. */ args_depth = TMPL_ARGS_DEPTH (args); parms_depth = TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (DECL_TI_TEMPLATE (t))); if (args_depth > parms_depth && !DECL_TEMPLATE_SPECIALIZATION (t)) args = get_innermost_template_args (args, parms_depth); } else { /* This special case arises when we have something like this: template <class T> struct S { friend void f<int>(int, double); }; Here, the DECL_TI_TEMPLATE for the friend declaration will be an IDENTIFIER_NODE. We are being called from tsubst_friend_function, and we want only to create a new decl (R) with appropriate types so that we can call determine_specialization. */ gen_tmpl = NULL_TREE; } if (DECL_CLASS_SCOPE_P (t)) { if (DECL_NAME (t) == constructor_name (DECL_CONTEXT (t))) member = 2; else member = 1; ctx = tsubst_aggr_type (DECL_CONTEXT (t), args, complain, t, /*entering_scope=*/1); } else { member = 0; ctx = DECL_CONTEXT (t); } type = tsubst (TREE_TYPE (t), args, complain, in_decl); if (type == error_mark_node) RETURN (error_mark_node); /* We do NOT check for matching decls pushed separately at this point, as they may not represent instantiations of this template, and in any case are considered separate under the discrete model. */ r = copy_decl (t); DECL_USE_TEMPLATE (r) = 0; TREE_TYPE (r) = type; /* Clear out the mangled name and RTL for the instantiation. */ SET_DECL_ASSEMBLER_NAME (r, NULL_TREE); SET_DECL_RTL (r, NULL_RTX); /* Leave DECL_INITIAL set on deleted instantiations. */ if (!DECL_DELETED_FN (r)) DECL_INITIAL (r) = NULL_TREE; DECL_CONTEXT (r) = ctx; if (member && DECL_CONV_FN_P (r)) /* Type-conversion operator. Reconstruct the name, in case it's the name of one of the template's parameters. */ DECL_NAME (r) = mangle_conv_op_name_for_type (TREE_TYPE (type)); DECL_ARGUMENTS (r) = tsubst (DECL_ARGUMENTS (t), args, complain, t); DECL_RESULT (r) = NULL_TREE; TREE_STATIC (r) = 0; TREE_PUBLIC (r) = TREE_PUBLIC (t); DECL_EXTERNAL (r) = 1; /* If this is an instantiation of a function with internal linkage, we already know what object file linkage will be assigned to the instantiation. */ DECL_INTERFACE_KNOWN (r) = !TREE_PUBLIC (r); DECL_DEFER_OUTPUT (r) = 0; TREE_CHAIN (r) = NULL_TREE; DECL_PENDING_INLINE_INFO (r) = 0; DECL_PENDING_INLINE_P (r) = 0; DECL_SAVED_TREE (r) = NULL_TREE; DECL_STRUCT_FUNCTION (r) = NULL; TREE_USED (r) = 0; /* We'll re-clone as appropriate in instantiate_template. */ DECL_CLONED_FUNCTION (r) = NULL_TREE; /* If we aren't complaining now, return on error before we register the specialization so that we'll complain eventually. */ if ((complain & tf_error) == 0 && IDENTIFIER_OPNAME_P (DECL_NAME (r)) && !grok_op_properties (r, /*complain=*/false)) RETURN (error_mark_node); /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do this in the special friend case mentioned above where GEN_TMPL is NULL. */ if (gen_tmpl) { DECL_TEMPLATE_INFO (r) = build_template_info (gen_tmpl, argvec); SET_DECL_IMPLICIT_INSTANTIATION (r); register_specialization (r, gen_tmpl, argvec, false, hash); /* We're not supposed to instantiate default arguments until they are called, for a template. But, for a declaration like: template <class T> void f () { extern void g(int i = T()); } we should do the substitution when the template is instantiated. We handle the member function case in instantiate_class_template since the default arguments might refer to other members of the class. */ if (!member && !PRIMARY_TEMPLATE_P (gen_tmpl) && !uses_template_parms (argvec)) tsubst_default_arguments (r); } else DECL_TEMPLATE_INFO (r) = NULL_TREE; /* Copy the list of befriending classes. */ for (friends = &DECL_BEFRIENDING_CLASSES (r); *friends; friends = &TREE_CHAIN (*friends)) { *friends = copy_node (*friends); TREE_VALUE (*friends) = tsubst (TREE_VALUE (*friends), args, complain, in_decl); } if (DECL_CONSTRUCTOR_P (r) || DECL_DESTRUCTOR_P (r)) { maybe_retrofit_in_chrg (r); if (DECL_CONSTRUCTOR_P (r)) grok_ctor_properties (ctx, r); /* If this is an instantiation of a member template, clone it. If it isn't, that'll be handled by clone_constructors_and_destructors. */ if (PRIMARY_TEMPLATE_P (gen_tmpl)) clone_function_decl (r, /*update_method_vec_p=*/0); } else if ((complain & tf_error) != 0 && IDENTIFIER_OPNAME_P (DECL_NAME (r)) && !grok_op_properties (r, /*complain=*/true)) RETURN (error_mark_node); if (DECL_FRIEND_P (t) && DECL_FRIEND_CONTEXT (t)) SET_DECL_FRIEND_CONTEXT (r, tsubst (DECL_FRIEND_CONTEXT (t), args, complain, in_decl)); /* Possibly limit visibility based on template args. */ DECL_VISIBILITY (r) = VISIBILITY_DEFAULT; if (DECL_VISIBILITY_SPECIFIED (t)) { DECL_VISIBILITY_SPECIFIED (r) = 0; DECL_ATTRIBUTES (r) = remove_attribute ("visibility", DECL_ATTRIBUTES (r)); } determine_visibility (r); if (DECL_DEFAULTED_OUTSIDE_CLASS_P (r) && !processing_template_decl) defaulted_late_check (r); apply_late_template_attributes (&r, DECL_ATTRIBUTES (r), 0, args, complain, in_decl); } break; case PARM_DECL: { tree type = NULL_TREE; int i, len = 1; tree expanded_types = NULL_TREE; tree prev_r = NULL_TREE; tree first_r = NULL_TREE; if (FUNCTION_PARAMETER_PACK_P (t)) { /* If there is a local specialization that isn't a parameter pack, it means that we're doing a "simple" substitution from inside tsubst_pack_expansion. Just return the local specialization (which will be a single parm). */ tree spec = retrieve_local_specialization (t); if (spec && TREE_CODE (spec) == PARM_DECL && TREE_CODE (TREE_TYPE (spec)) != TYPE_PACK_EXPANSION) RETURN (spec); /* Expand the TYPE_PACK_EXPANSION that provides the types for the parameters in this function parameter pack. */ expanded_types = tsubst_pack_expansion (TREE_TYPE (t), args, complain, in_decl); if (TREE_CODE (expanded_types) == TREE_VEC) { len = TREE_VEC_LENGTH (expanded_types); /* Zero-length parameter packs are boring. Just substitute into the chain. */ if (len == 0) RETURN (tsubst (TREE_CHAIN (t), args, complain, TREE_CHAIN (t))); } else { /* All we did was update the type. Make a note of that. */ type = expanded_types; expanded_types = NULL_TREE; } } /* Loop through all of the parameter's we'll build. When T is a function parameter pack, LEN is the number of expanded types in EXPANDED_TYPES; otherwise, LEN is 1. */ r = NULL_TREE; for (i = 0; i < len; ++i) { prev_r = r; r = copy_node (t); if (DECL_TEMPLATE_PARM_P (t)) SET_DECL_TEMPLATE_PARM_P (r); /* An argument of a function parameter pack is not a parameter pack. */ FUNCTION_PARAMETER_PACK_P (r) = false; if (expanded_types) /* We're on the Ith parameter of the function parameter pack. */ { /* Get the Ith type. */ type = TREE_VEC_ELT (expanded_types, i); if (DECL_NAME (r)) /* Rename the parameter to include the index. */ DECL_NAME (r) = make_ith_pack_parameter_name (DECL_NAME (r), i); } else if (!type) /* We're dealing with a normal parameter. */ type = tsubst (TREE_TYPE (t), args, complain, in_decl); type = type_decays_to (type); TREE_TYPE (r) = type; cp_apply_type_quals_to_decl (cp_type_quals (type), r); if (DECL_INITIAL (r)) { if (TREE_CODE (DECL_INITIAL (r)) != TEMPLATE_PARM_INDEX) DECL_INITIAL (r) = TREE_TYPE (r); else DECL_INITIAL (r) = tsubst (DECL_INITIAL (r), args, complain, in_decl); } DECL_CONTEXT (r) = NULL_TREE; if (!DECL_TEMPLATE_PARM_P (r)) DECL_ARG_TYPE (r) = type_passed_as (type); apply_late_template_attributes (&r, DECL_ATTRIBUTES (r), 0, args, complain, in_decl); /* Keep track of the first new parameter we generate. That's what will be returned to the caller. */ if (!first_r) first_r = r; /* Build a proper chain of parameters when substituting into a function parameter pack. */ if (prev_r) TREE_CHAIN (prev_r) = r; } if (TREE_CHAIN (t)) TREE_CHAIN (r) = tsubst (TREE_CHAIN (t), args, complain, TREE_CHAIN (t)); /* FIRST_R contains the start of the chain we've built. */ r = first_r; } break; case FIELD_DECL: { tree type; r = copy_decl (t); type = tsubst (TREE_TYPE (t), args, complain, in_decl); if (type == error_mark_node) RETURN (error_mark_node); TREE_TYPE (r) = type; cp_apply_type_quals_to_decl (cp_type_quals (type), r); /* DECL_INITIAL gives the number of bits in a bit-field. */ DECL_INITIAL (r) = tsubst_expr (DECL_INITIAL (t), args, complain, in_decl, /*integral_constant_expression_p=*/true); /* We don't have to set DECL_CONTEXT here; it is set by finish_member_declaration. */ TREE_CHAIN (r) = NULL_TREE; if (VOID_TYPE_P (type)) error ("instantiation of %q+D as type %qT", r, type); apply_late_template_attributes (&r, DECL_ATTRIBUTES (r), 0, args, complain, in_decl); } break; case USING_DECL: /* We reach here only for member using decls. */ if (DECL_DEPENDENT_P (t)) { r = do_class_using_decl (tsubst_copy (USING_DECL_SCOPE (t), args, complain, in_decl), tsubst_copy (DECL_NAME (t), args, complain, in_decl)); if (!r) r = error_mark_node; else { TREE_PROTECTED (r) = TREE_PROTECTED (t); TREE_PRIVATE (r) = TREE_PRIVATE (t); } } else { r = copy_node (t); TREE_CHAIN (r) = NULL_TREE; } break; case TYPE_DECL: case VAR_DECL: { tree argvec = NULL_TREE; tree gen_tmpl = NULL_TREE; tree spec; tree tmpl = NULL_TREE; tree ctx; tree type = NULL_TREE; bool local_p; if (TREE_CODE (t) == TYPE_DECL && t == TYPE_MAIN_DECL (TREE_TYPE (t))) { /* If this is the canonical decl, we don't have to mess with instantiations, and often we can't (for typename, template type parms and such). Note that TYPE_NAME is not correct for the above test if we've copied the type for a typedef. */ type = tsubst (TREE_TYPE (t), args, complain, in_decl); if (type == error_mark_node) RETURN (error_mark_node); r = TYPE_NAME (type); break; } /* Check to see if we already have the specialization we need. */ spec = NULL_TREE; if (DECL_CLASS_SCOPE_P (t) || DECL_NAMESPACE_SCOPE_P (t)) { /* T is a static data member or namespace-scope entity. We have to substitute into namespace-scope variables (even though such entities are never templates) because of cases like: template <class T> void f() { extern T t; } where the entity referenced is not known until instantiation time. */ local_p = false; ctx = DECL_CONTEXT (t); if (DECL_CLASS_SCOPE_P (t)) { ctx = tsubst_aggr_type (ctx, args, complain, in_decl, /*entering_scope=*/1); /* If CTX is unchanged, then T is in fact the specialization we want. That situation occurs when referencing a static data member within in its own class. We can use pointer equality, rather than same_type_p, because DECL_CONTEXT is always canonical. */ if (ctx == DECL_CONTEXT (t)) spec = t; } if (!spec) { tmpl = DECL_TI_TEMPLATE (t); gen_tmpl = most_general_template (tmpl); argvec = tsubst (DECL_TI_ARGS (t), args, complain, in_decl); hash = hash_tmpl_and_args (gen_tmpl, argvec); spec = retrieve_specialization (gen_tmpl, argvec, hash); } } else { /* A local variable. */ local_p = true; /* Subsequent calls to pushdecl will fill this in. */ ctx = NULL_TREE; spec = retrieve_local_specialization (t); } /* If we already have the specialization we need, there is nothing more to do. */ if (spec) { r = spec; break; } /* Create a new node for the specialization we need. */ r = copy_decl (t); if (type == NULL_TREE) { if (is_typedef_decl (t)) type = DECL_ORIGINAL_TYPE (t); else type = TREE_TYPE (t); type = tsubst (type, args, complain, in_decl); } if (TREE_CODE (r) == VAR_DECL) { /* Even if the original location is out of scope, the newly substituted one is not. */ DECL_DEAD_FOR_LOCAL (r) = 0; DECL_INITIALIZED_P (r) = 0; DECL_TEMPLATE_INSTANTIATED (r) = 0; if (type == error_mark_node) RETURN (error_mark_node); if (TREE_CODE (type) == FUNCTION_TYPE) { /* It may seem that this case cannot occur, since: typedef void f(); void g() { f x; } declares a function, not a variable. However: typedef void f(); template <typename T> void g() { T t; } template void g<f>(); is an attempt to declare a variable with function type. */ error ("variable %qD has function type", /* R is not yet sufficiently initialized, so we just use its name. */ DECL_NAME (r)); RETURN (error_mark_node); } type = complete_type (type); DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (r) = DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (t); type = check_var_type (DECL_NAME (r), type); if (DECL_HAS_VALUE_EXPR_P (t)) { tree ve = DECL_VALUE_EXPR (t); ve = tsubst_expr (ve, args, complain, in_decl, /*constant_expression_p=*/false); SET_DECL_VALUE_EXPR (r, ve); } } else if (DECL_SELF_REFERENCE_P (t)) SET_DECL_SELF_REFERENCE_P (r); TREE_TYPE (r) = type; cp_apply_type_quals_to_decl (cp_type_quals (type), r); DECL_CONTEXT (r) = ctx; /* Clear out the mangled name and RTL for the instantiation. */ SET_DECL_ASSEMBLER_NAME (r, NULL_TREE); if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_DECL_WRTL)) SET_DECL_RTL (r, NULL_RTX); /* The initializer must not be expanded until it is required; see [temp.inst]. */ DECL_INITIAL (r) = NULL_TREE; if (CODE_CONTAINS_STRUCT (TREE_CODE (t), TS_DECL_WRTL)) SET_DECL_RTL (r, NULL_RTX); DECL_SIZE (r) = DECL_SIZE_UNIT (r) = 0; if (TREE_CODE (r) == VAR_DECL) { /* Possibly limit visibility based on template args. */ DECL_VISIBILITY (r) = VISIBILITY_DEFAULT; if (DECL_VISIBILITY_SPECIFIED (t)) { DECL_VISIBILITY_SPECIFIED (r) = 0; DECL_ATTRIBUTES (r) = remove_attribute ("visibility", DECL_ATTRIBUTES (r)); } determine_visibility (r); } if (!local_p) { /* A static data member declaration is always marked external when it is declared in-class, even if an initializer is present. We mimic the non-template processing here. */ DECL_EXTERNAL (r) = 1; register_specialization (r, gen_tmpl, argvec, false, hash); DECL_TEMPLATE_INFO (r) = build_template_info (tmpl, argvec); SET_DECL_IMPLICIT_INSTANTIATION (r); } else if (cp_unevaluated_operand) { /* We're substituting this var in a decltype outside of its scope, such as for a lambda return type. Don't add it to local_specializations, do perform auto deduction. */ tree auto_node = type_uses_auto (type); tree init = tsubst_expr (DECL_INITIAL (t), args, complain, in_decl, /*constant_expression_p=*/false); if (auto_node && init && describable_type (init)) { type = do_auto_deduction (type, init, auto_node); TREE_TYPE (r) = type; } } else register_local_specialization (r, t); TREE_CHAIN (r) = NULL_TREE; apply_late_template_attributes (&r, DECL_ATTRIBUTES (r), /*flags=*/0, args, complain, in_decl); /* Preserve a typedef that names a type. */ if (is_typedef_decl (r)) { DECL_ORIGINAL_TYPE (r) = NULL_TREE; set_underlying_type (r); } layout_decl (r, 0); } break; default: gcc_unreachable (); } #undef RETURN out: /* Restore the file and line information. */ input_location = saved_loc; return r; } /* Substitute into the ARG_TYPES of a function type. */ static tree tsubst_arg_types (tree arg_types, tree args, tsubst_flags_t complain, tree in_decl) { tree remaining_arg_types; tree type = NULL_TREE; int i = 1; tree expanded_args = NULL_TREE; tree default_arg; if (!arg_types || arg_types == void_list_node) return arg_types; remaining_arg_types = tsubst_arg_types (TREE_CHAIN (arg_types), args, complain, in_decl); if (remaining_arg_types == error_mark_node) return error_mark_node; if (PACK_EXPANSION_P (TREE_VALUE (arg_types))) { /* For a pack expansion, perform substitution on the entire expression. Later on, we'll handle the arguments one-by-one. */ expanded_args = tsubst_pack_expansion (TREE_VALUE (arg_types), args, complain, in_decl); if (TREE_CODE (expanded_args) == TREE_VEC) /* So that we'll spin through the parameters, one by one. */ i = TREE_VEC_LENGTH (expanded_args); else { /* We only partially substituted into the parameter pack. Our type is TYPE_PACK_EXPANSION. */ type = expanded_args; expanded_args = NULL_TREE; } } while (i > 0) { --i; if (expanded_args) type = TREE_VEC_ELT (expanded_args, i); else if (!type) type = tsubst (TREE_VALUE (arg_types), args, complain, in_decl); if (type == error_mark_node) return error_mark_node; if (VOID_TYPE_P (type)) { if (complain & tf_error) { error ("invalid parameter type %qT", type); if (in_decl) error ("in declaration %q+D", in_decl); } return error_mark_node; } /* Do array-to-pointer, function-to-pointer conversion, and ignore top-level qualifiers as required. */ type = TYPE_MAIN_VARIANT (type_decays_to (type)); /* We do not substitute into default arguments here. The standard mandates that they be instantiated only when needed, which is done in build_over_call. */ default_arg = TREE_PURPOSE (arg_types); if (default_arg && TREE_CODE (default_arg) == DEFAULT_ARG) { /* We've instantiated a template before its default arguments have been parsed. This can happen for a nested template class, and is not an error unless we require the default argument in a call of this function. */ remaining_arg_types = tree_cons (default_arg, type, remaining_arg_types); VEC_safe_push (tree, gc, DEFARG_INSTANTIATIONS (default_arg), remaining_arg_types); } else remaining_arg_types = hash_tree_cons (default_arg, type, remaining_arg_types); } return remaining_arg_types; } /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does *not* handle the exception-specification for FNTYPE, because the initial substitution of explicitly provided template parameters during argument deduction forbids substitution into the exception-specification: [temp.deduct] All references in the function type of the function template to the corresponding template parameters are replaced by the specified tem- plate argument values. If a substitution in a template parameter or in the function type of the function template results in an invalid type, type deduction fails. [Note: The equivalent substitution in exception specifications is done only when the function is instanti- ated, at which point a program is ill-formed if the substitution results in an invalid type.] */ static tree tsubst_function_type (tree t, tree args, tsubst_flags_t complain, tree in_decl) { tree return_type; tree arg_types; tree fntype; /* The TYPE_CONTEXT is not used for function/method types. */ gcc_assert (TYPE_CONTEXT (t) == NULL_TREE); /* Substitute the return type. */ return_type = tsubst (TREE_TYPE (t), args, complain, in_decl); if (return_type == error_mark_node) return error_mark_node; /* The standard does not presently indicate that creation of a function type with an invalid return type is a deduction failure. However, that is clearly analogous to creating an array of "void" or a reference to a reference. This is core issue #486. */ if (TREE_CODE (return_type) == ARRAY_TYPE || TREE_CODE (return_type) == FUNCTION_TYPE) { if (complain & tf_error) { if (TREE_CODE (return_type) == ARRAY_TYPE) error ("function returning an array"); else error ("function returning a function"); } return error_mark_node; } /* Substitute the argument types. */ arg_types = tsubst_arg_types (TYPE_ARG_TYPES (t), args, complain, in_decl); if (arg_types == error_mark_node) return error_mark_node; /* Construct a new type node and return it. */ if (TREE_CODE (t) == FUNCTION_TYPE) fntype = build_function_type (return_type, arg_types); else { tree r = TREE_TYPE (TREE_VALUE (arg_types)); if (! MAYBE_CLASS_TYPE_P (r)) { /* [temp.deduct] Type deduction may fail for any of the following reasons: -- Attempting to create "pointer to member of T" when T is not a class type. */ if (complain & tf_error) error ("creating pointer to member function of non-class type %qT", r); return error_mark_node; } fntype = build_method_type_directly (r, return_type, TREE_CHAIN (arg_types)); } fntype = cp_build_qualified_type_real (fntype, TYPE_QUALS (t), complain); fntype = cp_build_type_attribute_variant (fntype, TYPE_ATTRIBUTES (t)); return fntype; } /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template ARGS into that specification, and return the substituted specification. If there is no specification, return NULL_TREE. */ static tree tsubst_exception_specification (tree fntype, tree args, tsubst_flags_t complain, tree in_decl) { tree specs; tree new_specs; specs = TYPE_RAISES_EXCEPTIONS (fntype); new_specs = NULL_TREE; if (specs) { if (! TREE_VALUE (specs)) new_specs = specs; else while (specs) { tree spec; int i, len = 1; tree expanded_specs = NULL_TREE; if (PACK_EXPANSION_P (TREE_VALUE (specs))) { /* Expand the pack expansion type. */ expanded_specs = tsubst_pack_expansion (TREE_VALUE (specs), args, complain, in_decl); if (expanded_specs == error_mark_node) return error_mark_node; else if (TREE_CODE (expanded_specs) == TREE_VEC) len = TREE_VEC_LENGTH (expanded_specs); else { /* We're substituting into a member template, so we got a TYPE_PACK_EXPANSION back. Add that expansion and move on. */ gcc_assert (TREE_CODE (expanded_specs) == TYPE_PACK_EXPANSION); new_specs = add_exception_specifier (new_specs, expanded_specs, complain); specs = TREE_CHAIN (specs); continue; } } for (i = 0; i < len; ++i) { if (expanded_specs) spec = TREE_VEC_ELT (expanded_specs, i); else spec = tsubst (TREE_VALUE (specs), args, complain, in_decl); if (spec == error_mark_node) return spec; new_specs = add_exception_specifier (new_specs, spec, complain); } specs = TREE_CHAIN (specs); } } return new_specs; } /* Take the tree structure T and replace template parameters used therein with the argument vector ARGS. IN_DECL is an associated decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE. Issue error and warning messages under control of COMPLAIN. Note that we must be relatively non-tolerant of extensions here, in order to preserve conformance; if we allow substitutions that should not be allowed, we may allow argument deductions that should not succeed, and therefore report ambiguous overload situations where there are none. In theory, we could allow the substitution, but indicate that it should have failed, and allow our caller to make sure that the right thing happens, but we don't try to do this yet. This function is used for dealing with types, decls and the like; for expressions, use tsubst_expr or tsubst_copy. */ tree tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl) { tree type, r; if (t == NULL_TREE || t == error_mark_node || t == integer_type_node || t == void_type_node || t == char_type_node || t == unknown_type_node || TREE_CODE (t) == NAMESPACE_DECL) return t; if (DECL_P (t)) return tsubst_decl (t, args, complain); if (args == NULL_TREE) return t; if (TREE_CODE (t) == IDENTIFIER_NODE) type = IDENTIFIER_TYPE_VALUE (t); else type = TREE_TYPE (t); gcc_assert (type != unknown_type_node); /* Reuse typedefs. We need to do this to handle dependent attributes, such as attribute aligned. */ if (TYPE_P (t) && TYPE_NAME (t) && TYPE_NAME (t) != TYPE_MAIN_DECL (t)) { tree decl = TYPE_NAME (t); if (DECL_CLASS_SCOPE_P (decl) && CLASSTYPE_TEMPLATE_INFO (DECL_CONTEXT (decl)) && uses_template_parms (DECL_CONTEXT (decl))) { tree tmpl = most_general_template (DECL_TI_TEMPLATE (decl)); tree gen_args = tsubst (DECL_TI_ARGS (decl), args, complain, in_decl); r = retrieve_specialization (tmpl, gen_args, 0); } else if (DECL_FUNCTION_SCOPE_P (decl) && DECL_TEMPLATE_INFO (DECL_CONTEXT (decl)) && uses_template_parms (DECL_TI_ARGS (DECL_CONTEXT (decl)))) r = retrieve_local_specialization (decl); else /* The typedef is from a non-template context. */ return t; if (r) { r = TREE_TYPE (r); r = cp_build_qualified_type_real (r, cp_type_quals (t) | cp_type_quals (r), complain | tf_ignore_bad_quals); return r; } /* Else we must be instantiating the typedef, so fall through. */ } if (type && TREE_CODE (t) != TYPENAME_TYPE && TREE_CODE (t) != TEMPLATE_TYPE_PARM && TREE_CODE (t) != IDENTIFIER_NODE && TREE_CODE (t) != FUNCTION_TYPE && TREE_CODE (t) != METHOD_TYPE) type = tsubst (type, args, complain, in_decl); if (type == error_mark_node) return error_mark_node; switch (TREE_CODE (t)) { case RECORD_TYPE: case UNION_TYPE: case ENUMERAL_TYPE: return tsubst_aggr_type (t, args, complain, in_decl, /*entering_scope=*/0); case ERROR_MARK: case IDENTIFIER_NODE: case VOID_TYPE: case REAL_TYPE: case COMPLEX_TYPE: case VECTOR_TYPE: case BOOLEAN_TYPE: case INTEGER_CST: case REAL_CST: case STRING_CST: return t; case INTEGER_TYPE: if (t == integer_type_node) return t; if (TREE_CODE (TYPE_MIN_VALUE (t)) == INTEGER_CST && TREE_CODE (TYPE_MAX_VALUE (t)) == INTEGER_CST) return t; { tree max, omax = TREE_OPERAND (TYPE_MAX_VALUE (t), 0); max = tsubst_expr (omax, args, complain, in_decl, /*integral_constant_expression_p=*/false); /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if needed. */ if (TREE_CODE (max) == NOP_EXPR && TREE_SIDE_EFFECTS (omax) && !TREE_TYPE (max)) TREE_TYPE (max) = TREE_TYPE (TREE_OPERAND (max, 0)); max = fold_decl_constant_value (max); /* If we're in a partial instantiation, preserve the magic NOP_EXPR with TREE_SIDE_EFFECTS that indicates this is not an integral constant expression. */ if (processing_template_decl && TREE_SIDE_EFFECTS (omax) && TREE_CODE (omax) == NOP_EXPR) { gcc_assert (TREE_CODE (max) == NOP_EXPR); TREE_SIDE_EFFECTS (max) = 1; } if (TREE_CODE (max) != INTEGER_CST && !at_function_scope_p () && !TREE_SIDE_EFFECTS (max) && !value_dependent_expression_p (max)) { if (complain & tf_error) error ("array bound is not an integer constant"); return error_mark_node; } /* [temp.deduct] Type deduction may fail for any of the following reasons: Attempting to create an array with a size that is zero or negative. */ if (integer_zerop (max) && !(complain & tf_error)) /* We must fail if performing argument deduction (as indicated by the state of complain), so that another substitution can be found. */ return error_mark_node; else if (TREE_CODE (max) == INTEGER_CST && INT_CST_LT (max, integer_zero_node)) { if (complain & tf_error) error ("creating array with negative size (%qE)", max); return error_mark_node; } return compute_array_index_type (NULL_TREE, max); } case TEMPLATE_TYPE_PARM: case TEMPLATE_TEMPLATE_PARM: case BOUND_TEMPLATE_TEMPLATE_PARM: case TEMPLATE_PARM_INDEX: { int idx; int level; int levels; tree arg = NULL_TREE; r = NULL_TREE; gcc_assert (TREE_VEC_LENGTH (args) > 0); template_parm_level_and_index (t, &level, &idx); levels = TMPL_ARGS_DEPTH (args); if (level <= levels) { arg = TMPL_ARG (args, level, idx); if (arg && TREE_CODE (arg) == ARGUMENT_PACK_SELECT) /* See through ARGUMENT_PACK_SELECT arguments. */ arg = ARGUMENT_PACK_SELECT_ARG (arg); } if (arg == error_mark_node) return error_mark_node; else if (arg != NULL_TREE) { if (ARGUMENT_PACK_P (arg)) /* If ARG is an argument pack, we don't actually want to perform a substitution here, because substitutions for argument packs are only done element-by-element. We can get to this point when substituting the type of a non-type template parameter pack, when that type actually contains template parameter packs from an outer template, e.g., template<typename... Types> struct A { template<Types... Values> struct B { }; }; */ return t; if (TREE_CODE (t) == TEMPLATE_TYPE_PARM) { int quals; gcc_assert (TYPE_P (arg)); /* cv-quals from the template are discarded when substituting in a function or reference type. */ if (TREE_CODE (arg) == FUNCTION_TYPE || TREE_CODE (arg) == METHOD_TYPE || TREE_CODE (arg) == REFERENCE_TYPE) quals = cp_type_quals (arg); else quals = cp_type_quals (arg) | cp_type_quals (t); return cp_build_qualified_type_real (arg, quals, complain | tf_ignore_bad_quals); } else if (TREE_CODE (t) == BOUND_TEMPLATE_TEMPLATE_PARM) { /* We are processing a type constructed from a template template parameter. */ tree argvec = tsubst (TYPE_TI_ARGS (t), args, complain, in_decl); if (argvec == error_mark_node) return error_mark_node; /* We can get a TEMPLATE_TEMPLATE_PARM here when we are resolving nested-types in the signature of a member function templates. Otherwise ARG is a TEMPLATE_DECL and is the real template to be instantiated. */ if (TREE_CODE (arg) == TEMPLATE_TEMPLATE_PARM) arg = TYPE_NAME (arg); r = lookup_template_class (arg, argvec, in_decl, DECL_CONTEXT (arg), /*entering_scope=*/0, complain); return cp_build_qualified_type_real (r, TYPE_QUALS (t), complain); } else /* TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX. */ return arg; } if (level == 1) /* This can happen during the attempted tsubst'ing in unify. This means that we don't yet have any information about the template parameter in question. */ return t; /* If we get here, we must have been looking at a parm for a more deeply nested template. Make a new version of this template parameter, but with a lower level. */ switch (TREE_CODE (t)) { case TEMPLATE_TYPE_PARM: case TEMPLATE_TEMPLATE_PARM: case BOUND_TEMPLATE_TEMPLATE_PARM: if (cp_type_quals (t)) { r = tsubst (TYPE_MAIN_VARIANT (t), args, complain, in_decl); r = cp_build_qualified_type_real (r, cp_type_quals (t), complain | (TREE_CODE (t) == TEMPLATE_TYPE_PARM ? tf_ignore_bad_quals : 0)); } else { r = copy_type (t); TEMPLATE_TYPE_PARM_INDEX (r) = reduce_template_parm_level (TEMPLATE_TYPE_PARM_INDEX (t), r, levels, args, complain); TYPE_STUB_DECL (r) = TYPE_NAME (r) = TEMPLATE_TYPE_DECL (r); TYPE_MAIN_VARIANT (r) = r; TYPE_POINTER_TO (r) = NULL_TREE; TYPE_REFERENCE_TO (r) = NULL_TREE; if (TREE_CODE (r) == TEMPLATE_TEMPLATE_PARM) /* We have reduced the level of the template template parameter, but not the levels of its template parameters, so canonical_type_parameter will not be able to find the canonical template template parameter for this level. Thus, we require structural equality checking to compare TEMPLATE_TEMPLATE_PARMs. */ SET_TYPE_STRUCTURAL_EQUALITY (r); else if (TYPE_STRUCTURAL_EQUALITY_P (t)) SET_TYPE_STRUCTURAL_EQUALITY (r); else TYPE_CANONICAL (r) = canonical_type_parameter (r); if (TREE_CODE (t) == BOUND_TEMPLATE_TEMPLATE_PARM) { tree argvec = tsubst (TYPE_TI_ARGS (t), args, complain, in_decl); if (argvec == error_mark_node) return error_mark_node; TEMPLATE_TEMPLATE_PARM_TEMPLATE_INFO (r) = build_template_info (TYPE_TI_TEMPLATE (t), argvec); } } break; case TEMPLATE_PARM_INDEX: r = reduce_template_parm_level (t, type, levels, args, complain); break; default: gcc_unreachable (); } return r; } case TREE_LIST: { tree purpose, value, chain; if (t == void_list_node) return t; purpose = TREE_PURPOSE (t); if (purpose) { purpose = tsubst (purpose, args, complain, in_decl); if (purpose == error_mark_node) return error_mark_node; } value = TREE_VALUE (t); if (value) { value = tsubst (value, args, complain, in_decl); if (value == error_mark_node) return error_mark_node; } chain = TREE_CHAIN (t); if (chain && chain != void_type_node) { chain = tsubst (chain, args, complain, in_decl); if (chain == error_mark_node) return error_mark_node; } if (purpose == TREE_PURPOSE (t) && value == TREE_VALUE (t) && chain == TREE_CHAIN (t)) return t; return hash_tree_cons (purpose, value, chain); } case TREE_BINFO: /* We should never be tsubsting a binfo. */ gcc_unreachable (); case TREE_VEC: /* A vector of template arguments. */ gcc_assert (!type); return tsubst_template_args (t, args, complain, in_decl); case POINTER_TYPE: case REFERENCE_TYPE: { enum tree_code code; if (type == TREE_TYPE (t) && TREE_CODE (type) != METHOD_TYPE) return t; code = TREE_CODE (t); /* [temp.deduct] Type deduction may fail for any of the following reasons: -- Attempting to create a pointer to reference type. -- Attempting to create a reference to a reference type or a reference to void. Core issue 106 says that creating a reference to a reference during instantiation is no longer a cause for failure. We only enforce this check in strict C++98 mode. */ if ((TREE_CODE (type) == REFERENCE_TYPE && (((cxx_dialect == cxx98) && flag_iso) || code != REFERENCE_TYPE)) || (code == REFERENCE_TYPE && TREE_CODE (type) == VOID_TYPE)) { static location_t last_loc; /* We keep track of the last time we issued this error message to avoid spewing a ton of messages during a single bad template instantiation. */ if (complain & tf_error && last_loc != input_location) { if (TREE_CODE (type) == VOID_TYPE) error ("forming reference to void"); else if (code == POINTER_TYPE) error ("forming pointer to reference type %qT", type); else error ("forming reference to reference type %qT", type); last_loc = input_location; } return error_mark_node; } else if (code == POINTER_TYPE) { r = build_pointer_type (type); if (TREE_CODE (type) == METHOD_TYPE) r = build_ptrmemfunc_type (r); } else if (TREE_CODE (type) == REFERENCE_TYPE) /* In C++0x, during template argument substitution, when there is an attempt to create a reference to a reference type, reference collapsing is applied as described in [14.3.1/4 temp.arg.type]: "If a template-argument for a template-parameter T names a type that is a reference to a type A, an attempt to create the type 'lvalue reference to cv T' creates the type 'lvalue reference to A,' while an attempt to create the type type rvalue reference to cv T' creates the type T" */ r = cp_build_reference_type (TREE_TYPE (type), TYPE_REF_IS_RVALUE (t) && TYPE_REF_IS_RVALUE (type)); else r = cp_build_reference_type (type, TYPE_REF_IS_RVALUE (t)); r = cp_build_qualified_type_real (r, TYPE_QUALS (t), complain); if (r != error_mark_node) /* Will this ever be needed for TYPE_..._TO values? */ layout_type (r); return r; } case OFFSET_TYPE: { r = tsubst (TYPE_OFFSET_BASETYPE (t), args, complain, in_decl); if (r == error_mark_node || !MAYBE_CLASS_TYPE_P (r)) { /* [temp.deduct] Type deduction may fail for any of the following reasons: -- Attempting to create "pointer to member of T" when T is not a class type. */ if (complain & tf_error) error ("creating pointer to member of non-class type %qT", r); return error_mark_node; } if (TREE_CODE (type) == REFERENCE_TYPE) { if (complain & tf_error) error ("creating pointer to member reference type %qT", type); return error_mark_node; } if (TREE_CODE (type) == VOID_TYPE) { if (complain & tf_error) error ("creating pointer to member of type void"); return error_mark_node; } gcc_assert (TREE_CODE (type) != METHOD_TYPE); if (TREE_CODE (type) == FUNCTION_TYPE) { /* The type of the implicit object parameter gets its cv-qualifiers from the FUNCTION_TYPE. */ tree memptr; tree method_type = build_memfn_type (type, r, cp_type_quals (type)); memptr = build_ptrmemfunc_type (build_pointer_type (method_type)); return cp_build_qualified_type_real (memptr, cp_type_quals (t), complain); } else return cp_build_qualified_type_real (build_ptrmem_type (r, type), TYPE_QUALS (t), complain); } case FUNCTION_TYPE: case METHOD_TYPE: { tree fntype; tree specs; fntype = tsubst_function_type (t, args, complain, in_decl); if (fntype == error_mark_node) return error_mark_node; /* Substitute the exception specification. */ specs = tsubst_exception_specification (t, args, complain, in_decl); if (specs == error_mark_node) return error_mark_node; if (specs) fntype = build_exception_variant (fntype, specs); return fntype; } case ARRAY_TYPE: { tree domain = tsubst (TYPE_DOMAIN (t), args, complain, in_decl); if (domain == error_mark_node) return error_mark_node; /* As an optimization, we avoid regenerating the array type if it will obviously be the same as T. */ if (type == TREE_TYPE (t) && domain == TYPE_DOMAIN (t)) return t; /* These checks should match the ones in grokdeclarator. [temp.deduct] The deduction may fail for any of the following reasons: -- Attempting to create an array with an element type that is void, a function type, or a reference type, or [DR337] an abstract class type. */ if (TREE_CODE (type) == VOID_TYPE || TREE_CODE (type) == FUNCTION_TYPE || TREE_CODE (type) == REFERENCE_TYPE) { if (complain & tf_error) error ("creating array of %qT", type); return error_mark_node; } if (CLASS_TYPE_P (type) && CLASSTYPE_PURE_VIRTUALS (type)) { if (complain & tf_error) error ("creating array of %qT, which is an abstract class type", type); return error_mark_node; } r = build_cplus_array_type (type, domain); if (TYPE_USER_ALIGN (t)) { TYPE_ALIGN (r) = TYPE_ALIGN (t); TYPE_USER_ALIGN (r) = 1; } return r; } case PLUS_EXPR: case MINUS_EXPR: { tree e1 = tsubst (TREE_OPERAND (t, 0), args, complain, in_decl); tree e2 = tsubst (TREE_OPERAND (t, 1), args, complain, in_decl); if (e1 == error_mark_node || e2 == error_mark_node) return error_mark_node; return fold_build2_loc (input_location, TREE_CODE (t), TREE_TYPE (t), e1, e2); } case NEGATE_EXPR: case NOP_EXPR: { tree e = tsubst (TREE_OPERAND (t, 0), args, complain, in_decl); if (e == error_mark_node) return error_mark_node; return fold_build1_loc (input_location, TREE_CODE (t), TREE_TYPE (t), e); } case TYPENAME_TYPE: { tree ctx = tsubst_aggr_type (TYPE_CONTEXT (t), args, complain, in_decl, /*entering_scope=*/1); tree f = tsubst_copy (TYPENAME_TYPE_FULLNAME (t), args, complain, in_decl); int quals; if (ctx == error_mark_node || f == error_mark_node) return error_mark_node; if (!MAYBE_CLASS_TYPE_P (ctx)) { if (complain & tf_error) error ("%qT is not a class, struct, or union type", ctx); return error_mark_node; } else if (!uses_template_parms (ctx) && !TYPE_BEING_DEFINED (ctx)) { /* Normally, make_typename_type does not require that the CTX have complete type in order to allow things like: template <class T> struct S { typename S<T>::X Y; }; But, such constructs have already been resolved by this point, so here CTX really should have complete type, unless it's a partial instantiation. */ if (!(complain & tf_no_class_instantiations)) ctx = complete_type (ctx); if (!COMPLETE_TYPE_P (ctx)) { if (complain & tf_error) cxx_incomplete_type_error (NULL_TREE, ctx); return error_mark_node; } } f = make_typename_type (ctx, f, typename_type, (complain & tf_error) | tf_keep_type_decl); if (f == error_mark_node) return f; if (TREE_CODE (f) == TYPE_DECL) { complain |= tf_ignore_bad_quals; f = TREE_TYPE (f); } if (TREE_CODE (f) != TYPENAME_TYPE) { if (TYPENAME_IS_ENUM_P (t) && TREE_CODE (f) != ENUMERAL_TYPE) error ("%qT resolves to %qT, which is not an enumeration type", t, f); else if (TYPENAME_IS_CLASS_P (t) && !CLASS_TYPE_P (f)) error ("%qT resolves to %qT, which is is not a class type", t, f); } /* cv-quals from the template are discarded when substituting in a function or reference type. */ if (TREE_CODE (f) == FUNCTION_TYPE || TREE_CODE (f) == METHOD_TYPE || TREE_CODE (f) == REFERENCE_TYPE) quals = cp_type_quals (f); else quals = cp_type_quals (f) | cp_type_quals (t); return cp_build_qualified_type_real (f, quals, complain); } case UNBOUND_CLASS_TEMPLATE: { tree ctx = tsubst_aggr_type (TYPE_CONTEXT (t), args, complain, in_decl, /*entering_scope=*/1); tree name = TYPE_IDENTIFIER (t); tree parm_list = DECL_TEMPLATE_PARMS (TYPE_NAME (t)); if (ctx == error_mark_node || name == error_mark_node) return error_mark_node; if (parm_list) parm_list = tsubst_template_parms (parm_list, args, complain); return make_unbound_class_template (ctx, name, parm_list, complain); } case INDIRECT_REF: case ADDR_EXPR: case CALL_EXPR: gcc_unreachable (); case ARRAY_REF: { tree e1 = tsubst (TREE_OPERAND (t, 0), args, complain, in_decl); tree e2 = tsubst_expr (TREE_OPERAND (t, 1), args, complain, in_decl, /*integral_constant_expression_p=*/false); if (e1 == error_mark_node || e2 == error_mark_node) return error_mark_node; return build_nt (ARRAY_REF, e1, e2, NULL_TREE, NULL_TREE); } case SCOPE_REF: { tree e1 = tsubst (TREE_OPERAND (t, 0), args, complain, in_decl); tree e2 = tsubst (TREE_OPERAND (t, 1), args, complain, in_decl); if (e1 == error_mark_node || e2 == error_mark_node) return error_mark_node; return build_qualified_name (/*type=*/NULL_TREE, e1, e2, QUALIFIED_NAME_IS_TEMPLATE (t)); } case TYPEOF_TYPE: { tree type; ++cp_unevaluated_operand; ++c_inhibit_evaluation_warnings; type = tsubst_expr (TYPEOF_TYPE_EXPR (t), args, complain, in_decl, /*integral_constant_expression_p=*/false); --cp_unevaluated_operand; --c_inhibit_evaluation_warnings; type = finish_typeof (type); return cp_build_qualified_type_real (type, cp_type_quals (t) | cp_type_quals (type), complain); } case DECLTYPE_TYPE: { tree type; ++cp_unevaluated_operand; ++c_inhibit_evaluation_warnings; type = tsubst_expr (DECLTYPE_TYPE_EXPR (t), args, complain, in_decl, /*integral_constant_expression_p=*/false); --cp_unevaluated_operand; --c_inhibit_evaluation_warnings; if (DECLTYPE_FOR_LAMBDA_CAPTURE (t)) type = lambda_capture_field_type (type); else if (DECLTYPE_FOR_LAMBDA_RETURN (t)) type = lambda_return_type (type); else type = finish_decltype_type (type, DECLTYPE_TYPE_ID_EXPR_OR_MEMBER_ACCESS_P (t)); return cp_build_qualified_type_real (type, cp_type_quals (t) | cp_type_quals (type), complain); } case TYPE_ARGUMENT_PACK: case NONTYPE_ARGUMENT_PACK: { tree r = TYPE_P (t) ? cxx_make_type (TREE_CODE (t)) : make_node (TREE_CODE (t)); tree packed_out = tsubst_template_args (ARGUMENT_PACK_ARGS (t), args, complain, in_decl); SET_ARGUMENT_PACK_ARGS (r, packed_out); /* For template nontype argument packs, also substitute into the type. */ if (TREE_CODE (t) == NONTYPE_ARGUMENT_PACK) TREE_TYPE (r) = tsubst (TREE_TYPE (t), args, complain, in_decl); return r; } break; default: sorry ("use of %qs in template", tree_code_name [(int) TREE_CODE (t)]); return error_mark_node; } } /* Like tsubst_expr for a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the expression on the left-hand side of the "." or "->" operator. */ static tree tsubst_baselink (tree baselink, tree object_type, tree args, tsubst_flags_t complain, tree in_decl) { tree name; tree qualifying_scope; tree fns; tree optype; tree template_args = 0; bool template_id_p = false; /* A baselink indicates a function from a base class. Both the BASELINK_ACCESS_BINFO and the base class referenced may indicate bases of the template class, rather than the instantiated class. In addition, lookups that were not ambiguous before may be ambiguous now. Therefore, we perform the lookup again. */ qualifying_scope = BINFO_TYPE (BASELINK_ACCESS_BINFO (baselink)); qualifying_scope = tsubst (qualifying_scope, args, complain, in_decl); fns = BASELINK_FUNCTIONS (baselink); optype = tsubst (BASELINK_OPTYPE (baselink), args, complain, in_decl); if (TREE_CODE (fns) == TEMPLATE_ID_EXPR) { template_id_p = true; template_args = TREE_OPERAND (fns, 1); fns = TREE_OPERAND (fns, 0); if (template_args) template_args = tsubst_template_args (template_args, args, complain, in_decl); } name = DECL_NAME (get_first_fn (fns)); if (IDENTIFIER_TYPENAME_P (name)) name = mangle_conv_op_name_for_type (optype); baselink = lookup_fnfields (qualifying_scope, name, /*protect=*/1); if (!baselink) return error_mark_node; /* If lookup found a single function, mark it as used at this point. (If it lookup found multiple functions the one selected later by overload resolution will be marked as used at that point.) */ if (BASELINK_P (baselink)) fns = BASELINK_FUNCTIONS (baselink); if (!template_id_p && !really_overloaded_fn (fns)) mark_used (OVL_CURRENT (fns)); /* Add back the template arguments, if present. */ if (BASELINK_P (baselink) && template_id_p) BASELINK_FUNCTIONS (baselink) = build_nt (TEMPLATE_ID_EXPR, BASELINK_FUNCTIONS (baselink), template_args); /* Update the conversion operator type. */ BASELINK_OPTYPE (baselink) = optype; if (!object_type) object_type = current_class_type; return adjust_result_of_qualified_name_lookup (baselink, qualifying_scope, object_type); } /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is true if the qualified-id will be a postfix-expression in-and-of itself; false if more of the postfix-expression follows the QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand of "&". */ static tree tsubst_qualified_id (tree qualified_id, tree args, tsubst_flags_t complain, tree in_decl, bool done, bool address_p) { tree expr; tree scope; tree name; bool is_template; tree template_args; gcc_assert (TREE_CODE (qualified_id) == SCOPE_REF); /* Figure out what name to look up. */ name = TREE_OPERAND (qualified_id, 1); if (TREE_CODE (name) == TEMPLATE_ID_EXPR) { is_template = true; template_args = TREE_OPERAND (name, 1); if (template_args) template_args = tsubst_template_args (template_args, args, complain, in_decl); name = TREE_OPERAND (name, 0); } else { is_template = false; template_args = NULL_TREE; } /* Substitute into the qualifying scope. When there are no ARGS, we are just trying to simplify a non-dependent expression. In that case the qualifying scope may be dependent, and, in any case, substituting will not help. */ scope = TREE_OPERAND (qualified_id, 0); if (args) { scope = tsubst (scope, args, complain, in_decl); expr = tsubst_copy (name, args, complain, in_decl); } else expr = name; if (dependent_scope_p (scope)) return build_qualified_name (NULL_TREE, scope, expr, QUALIFIED_NAME_IS_TEMPLATE (qualified_id)); if (!BASELINK_P (name) && !DECL_P (expr)) { if (TREE_CODE (expr) == BIT_NOT_EXPR) { /* A BIT_NOT_EXPR is used to represent a destructor. */ if (!check_dtor_name (scope, TREE_OPERAND (expr, 0))) { error ("qualifying type %qT does not match destructor name ~%qT", scope, TREE_OPERAND (expr, 0)); expr = error_mark_node; } else expr = lookup_qualified_name (scope, complete_dtor_identifier, /*is_type_p=*/0, false); } else expr = lookup_qualified_name (scope, expr, /*is_type_p=*/0, false); if (TREE_CODE (TREE_CODE (expr) == TEMPLATE_DECL ? DECL_TEMPLATE_RESULT (expr) : expr) == TYPE_DECL) { if (complain & tf_error) { error ("dependent-name %qE is parsed as a non-type, but " "instantiation yields a type", qualified_id); inform (input_location, "say %<typename %E%> if a type is meant", qualified_id); } return error_mark_node; } } if (DECL_P (expr)) { check_accessibility_of_qualified_id (expr, /*object_type=*/NULL_TREE, scope); /* Remember that there was a reference to this entity. */ mark_used (expr); } if (expr == error_mark_node || TREE_CODE (expr) == TREE_LIST) { if (complain & tf_error) qualified_name_lookup_error (scope, TREE_OPERAND (qualified_id, 1), expr, input_location); return error_mark_node; } if (is_template) expr = lookup_template_function (expr, template_args); if (expr == error_mark_node && complain & tf_error) qualified_name_lookup_error (scope, TREE_OPERAND (qualified_id, 1), expr, input_location); else if (TYPE_P (scope)) { expr = (adjust_result_of_qualified_name_lookup (expr, scope, current_class_type)); expr = (finish_qualified_id_expr (scope, expr, done, address_p, QUALIFIED_NAME_IS_TEMPLATE (qualified_id), /*template_arg_p=*/false)); } /* Expressions do not generally have reference type. */ if (TREE_CODE (expr) != SCOPE_REF /* However, if we're about to form a pointer-to-member, we just want the referenced member referenced. */ && TREE_CODE (expr) != OFFSET_REF) expr = convert_from_reference (expr); return expr; } /* Like tsubst, but deals with expressions. This function just replaces template parms; to finish processing the resultant expression, use tsubst_expr. */ static tree tsubst_copy (tree t, tree args, tsubst_flags_t complain, tree in_decl) { enum tree_code code; tree r; if (t == NULL_TREE || t == error_mark_node || args == NULL_TREE) return t; code = TREE_CODE (t); switch (code) { case PARM_DECL: r = retrieve_local_specialization (t); if (r == NULL) { tree c; /* This can happen for a parameter name used later in a function declaration (such as in a late-specified return type). Just make a dummy decl, since it's only used for its type. */ gcc_assert (cp_unevaluated_operand != 0); /* We copy T because want to tsubst the PARM_DECL only, not the following PARM_DECLs that are chained to T. */ c = copy_node (t); r = tsubst_decl (c, args, complain); /* Give it the template pattern as its context; its true context hasn't been instantiated yet and this is good enough for mangling. */ DECL_CONTEXT (r) = DECL_CONTEXT (t); } if (TREE_CODE (r) == ARGUMENT_PACK_SELECT) r = ARGUMENT_PACK_SELECT_ARG (r); mark_used (r); return r; case CONST_DECL: { tree enum_type; tree v; if (DECL_TEMPLATE_PARM_P (t)) return tsubst_copy (DECL_INITIAL (t), args, complain, in_decl); /* There is no need to substitute into namespace-scope enumerators. */ if (DECL_NAMESPACE_SCOPE_P (t)) return t; /* If ARGS is NULL, then T is known to be non-dependent. */ if (args == NULL_TREE) return integral_constant_value (t); /* Unfortunately, we cannot just call lookup_name here. Consider: template <int I> int f() { enum E { a = I }; struct S { void g() { E e = a; } }; }; When we instantiate f<7>::S::g(), say, lookup_name is not clever enough to find f<7>::a. */ enum_type = tsubst_aggr_type (TREE_TYPE (t), args, complain, in_decl, /*entering_scope=*/0); for (v = TYPE_VALUES (enum_type); v != NULL_TREE; v = TREE_CHAIN (v)) if (TREE_PURPOSE (v) == DECL_NAME (t)) return TREE_VALUE (v); /* We didn't find the name. That should never happen; if name-lookup found it during preliminary parsing, we should find it again here during instantiation. */ gcc_unreachable (); } return t; case FIELD_DECL: if (DECL_CONTEXT (t)) { tree ctx; ctx = tsubst_aggr_type (DECL_CONTEXT (t), args, complain, in_decl, /*entering_scope=*/1); if (ctx != DECL_CONTEXT (t)) { tree r = lookup_field (ctx, DECL_NAME (t), 0, false); if (!r) { if (complain & tf_error) error ("using invalid field %qD", t); return error_mark_node; } return r; } } return t; case VAR_DECL: case FUNCTION_DECL: if ((DECL_LANG_SPECIFIC (t) && DECL_TEMPLATE_INFO (t)) || local_variable_p (t)) t = tsubst (t, args, complain, in_decl); mark_used (t); return t; case BASELINK: return tsubst_baselink (t, current_class_type, args, complain, in_decl); case TEMPLATE_DECL: if (DECL_TEMPLATE_TEMPLATE_PARM_P (t)) return tsubst (TREE_TYPE (DECL_TEMPLATE_RESULT (t)), args, complain, in_decl); else if (DECL_FUNCTION_TEMPLATE_P (t) && DECL_MEMBER_TEMPLATE_P (t)) return tsubst (t, args, complain, in_decl); else if (DECL_CLASS_SCOPE_P (t) && uses_template_parms (DECL_CONTEXT (t))) { /* Template template argument like the following example need special treatment: template <template <class> class TT> struct C {}; template <class T> struct D { template <class U> struct E {}; C<E> c; // #1 }; D<int> d; // #2 We are processing the template argument `E' in #1 for the template instantiation #2. Originally, `E' is a TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we have to substitute this with one having context `D<int>'. */ tree context = tsubst (DECL_CONTEXT (t), args, complain, in_decl); return lookup_field (context, DECL_NAME(t), 0, false); } else /* Ordinary template template argument. */ return t; case CAST_EXPR: case REINTERPRET_CAST_EXPR: case CONST_CAST_EXPR: case STATIC_CAST_EXPR: case DYNAMIC_CAST_EXPR: case NOP_EXPR: return build1 (code, tsubst (TREE_TYPE (t), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl)); case SIZEOF_EXPR: if (PACK_EXPANSION_P (TREE_OPERAND (t, 0))) { /* We only want to compute the number of arguments. */ tree expanded = tsubst_pack_expansion (TREE_OPERAND (t, 0), args, complain, in_decl); int len = 0; if (TREE_CODE (expanded) == TREE_VEC) len = TREE_VEC_LENGTH (expanded); if (expanded == error_mark_node) return error_mark_node; else if (PACK_EXPANSION_P (expanded) || (TREE_CODE (expanded) == TREE_VEC && len > 0 && PACK_EXPANSION_P (TREE_VEC_ELT (expanded, len-1)))) { if (TREE_CODE (expanded) == TREE_VEC) expanded = TREE_VEC_ELT (expanded, len - 1); if (TYPE_P (expanded)) return cxx_sizeof_or_alignof_type (expanded, SIZEOF_EXPR, complain & tf_error); else return cxx_sizeof_or_alignof_expr (expanded, SIZEOF_EXPR, complain & tf_error); } else return build_int_cst (size_type_node, len); } /* Fall through */ case INDIRECT_REF: case NEGATE_EXPR: case TRUTH_NOT_EXPR: case BIT_NOT_EXPR: case ADDR_EXPR: case UNARY_PLUS_EXPR: /* Unary + */ case ALIGNOF_EXPR: case ARROW_EXPR: case THROW_EXPR: case TYPEID_EXPR: case REALPART_EXPR: case IMAGPART_EXPR: return build1 (code, tsubst (TREE_TYPE (t), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl)); case COMPONENT_REF: { tree object; tree name; object = tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl); name = TREE_OPERAND (t, 1); if (TREE_CODE (name) == BIT_NOT_EXPR) { name = tsubst_copy (TREE_OPERAND (name, 0), args, complain, in_decl); name = build1 (BIT_NOT_EXPR, NULL_TREE, name); } else if (TREE_CODE (name) == SCOPE_REF && TREE_CODE (TREE_OPERAND (name, 1)) == BIT_NOT_EXPR) { tree base = tsubst_copy (TREE_OPERAND (name, 0), args, complain, in_decl); name = TREE_OPERAND (name, 1); name = tsubst_copy (TREE_OPERAND (name, 0), args, complain, in_decl); name = build1 (BIT_NOT_EXPR, NULL_TREE, name); name = build_qualified_name (/*type=*/NULL_TREE, base, name, /*template_p=*/false); } else if (TREE_CODE (name) == BASELINK) name = tsubst_baselink (name, non_reference (TREE_TYPE (object)), args, complain, in_decl); else name = tsubst_copy (name, args, complain, in_decl); return build_nt (COMPONENT_REF, object, name, NULL_TREE); } case PLUS_EXPR: case MINUS_EXPR: case MULT_EXPR: case TRUNC_DIV_EXPR: case CEIL_DIV_EXPR: case FLOOR_DIV_EXPR: case ROUND_DIV_EXPR: case EXACT_DIV_EXPR: case BIT_AND_EXPR: case BIT_IOR_EXPR: case BIT_XOR_EXPR: case TRUNC_MOD_EXPR: case FLOOR_MOD_EXPR: case TRUTH_ANDIF_EXPR: case TRUTH_ORIF_EXPR: case TRUTH_AND_EXPR: case TRUTH_OR_EXPR: case RSHIFT_EXPR: case LSHIFT_EXPR: case RROTATE_EXPR: case LROTATE_EXPR: case EQ_EXPR: case NE_EXPR: case MAX_EXPR: case MIN_EXPR: case LE_EXPR: case GE_EXPR: case LT_EXPR: case GT_EXPR: case COMPOUND_EXPR: case DOTSTAR_EXPR: case MEMBER_REF: case PREDECREMENT_EXPR: case PREINCREMENT_EXPR: case POSTDECREMENT_EXPR: case POSTINCREMENT_EXPR: return build_nt (code, tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 1), args, complain, in_decl)); case SCOPE_REF: return build_qualified_name (/*type=*/NULL_TREE, tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 1), args, complain, in_decl), QUALIFIED_NAME_IS_TEMPLATE (t)); case ARRAY_REF: return build_nt (ARRAY_REF, tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 1), args, complain, in_decl), NULL_TREE, NULL_TREE); case CALL_EXPR: { int n = VL_EXP_OPERAND_LENGTH (t); tree result = build_vl_exp (CALL_EXPR, n); int i; for (i = 0; i < n; i++) TREE_OPERAND (t, i) = tsubst_copy (TREE_OPERAND (t, i), args, complain, in_decl); return result; } case COND_EXPR: case MODOP_EXPR: case PSEUDO_DTOR_EXPR: { r = build_nt (code, tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 1), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 2), args, complain, in_decl)); TREE_NO_WARNING (r) = TREE_NO_WARNING (t); return r; } case NEW_EXPR: { r = build_nt (code, tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 1), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 2), args, complain, in_decl)); NEW_EXPR_USE_GLOBAL (r) = NEW_EXPR_USE_GLOBAL (t); return r; } case DELETE_EXPR: { r = build_nt (code, tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl), tsubst_copy (TREE_OPERAND (t, 1), args, complain, in_decl)); DELETE_EXPR_USE_GLOBAL (r) = DELETE_EXPR_USE_GLOBAL (t); DELETE_EXPR_USE_VEC (r) = DELETE_EXPR_USE_VEC (t); return r; } case TEMPLATE_ID_EXPR: { /* Substituted template arguments */ tree fn = TREE_OPERAND (t, 0); tree targs = TREE_OPERAND (t, 1); fn = tsubst_copy (fn, args, complain, in_decl); if (targs) targs = tsubst_template_args (targs, args, complain, in_decl); return lookup_template_function (fn, targs); } case TREE_LIST: { tree purpose, value, chain; if (t == void_list_node) return t; purpose = TREE_PURPOSE (t); if (purpose) purpose = tsubst_copy (purpose, args, complain, in_decl); value = TREE_VALUE (t); if (value) value = tsubst_copy (value, args, complain, in_decl); chain = TREE_CHAIN (t); if (chain && chain != void_type_node) chain = tsubst_copy (chain, args, complain, in_decl); if (purpose == TREE_PURPOSE (t) && value == TREE_VALUE (t) && chain == TREE_CHAIN (t)) return t; return tree_cons (purpose, value, chain); } case RECORD_TYPE: case UNION_TYPE: case ENUMERAL_TYPE: case INTEGER_TYPE: case TEMPLATE_TYPE_PARM: case TEMPLATE_TEMPLATE_PARM: case BOUND_TEMPLATE_TEMPLATE_PARM: case TEMPLATE_PARM_INDEX: case POINTER_TYPE: case REFERENCE_TYPE: case OFFSET_TYPE: case FUNCTION_TYPE: case METHOD_TYPE: case ARRAY_TYPE: case TYPENAME_TYPE: case UNBOUND_CLASS_TEMPLATE: case TYPEOF_TYPE: case DECLTYPE_TYPE: case TYPE_DECL: return tsubst (t, args, complain, in_decl); case IDENTIFIER_NODE: if (IDENTIFIER_TYPENAME_P (t)) { tree new_type = tsubst (TREE_TYPE (t), args, complain, in_decl); return mangle_conv_op_name_for_type (new_type); } else return t; case CONSTRUCTOR: /* This is handled by tsubst_copy_and_build. */ gcc_unreachable (); case VA_ARG_EXPR: return build_x_va_arg (tsubst_copy (TREE_OPERAND (t, 0), args, complain, in_decl), tsubst (TREE_TYPE (t), args, complain, in_decl)); case CLEANUP_POINT_EXPR: /* We shouldn't have built any of these during initial template generation. Instead, they should be built during instantiation in response to the saved STMT_IS_FULL_EXPR_P setting. */ gcc_unreachable (); case OFFSET_REF: mark_used (TREE_OPERAND (t, 1)); return t; case EXPR_PACK_EXPANSION: error ("invalid use of pack expansion expression"); return error_mark_node; case NONTYPE_ARGUMENT_PACK: error ("use %<...%> to expand argument pack"); return error_mark_node; default: return t; } } /* Like tsubst_copy, but specifically for OpenMP clauses. */ static tree tsubst_omp_clauses (tree clauses, tree args, tsubst_flags_t complain, tree in_decl) { tree new_clauses = NULL, nc, oc; for (oc = clauses; oc ; oc = OMP_CLAUSE_CHAIN (oc)) { nc = copy_node (oc); OMP_CLAUSE_CHAIN (nc) = new_clauses; new_clauses = nc; switch (OMP_CLAUSE_CODE (nc)) { case OMP_CLAUSE_LASTPRIVATE: if (OMP_CLAUSE_LASTPRIVATE_STMT (oc)) { OMP_CLAUSE_LASTPRIVATE_STMT (nc) = push_stmt_list (); tsubst_expr (OMP_CLAUSE_LASTPRIVATE_STMT (oc), args, complain, in_decl, /*integral_constant_expression_p=*/false); OMP_CLAUSE_LASTPRIVATE_STMT (nc) = pop_stmt_list (OMP_CLAUSE_LASTPRIVATE_STMT (nc)); } /* FALLTHRU */ case OMP_CLAUSE_PRIVATE: case OMP_CLAUSE_SHARED: case OMP_CLAUSE_FIRSTPRIVATE: case OMP_CLAUSE_REDUCTION: case OMP_CLAUSE_COPYIN: case OMP_CLAUSE_COPYPRIVATE: case OMP_CLAUSE_IF: case OMP_CLAUSE_NUM_THREADS: case OMP_CLAUSE_SCHEDULE: case OMP_CLAUSE_COLLAPSE: OMP_CLAUSE_OPERAND (nc, 0) = tsubst_expr (OMP_CLAUSE_OPERAND (oc, 0), args, complain, in_decl, /*integral_constant_expression_p=*/false); break; case OMP_CLAUSE_NOWAIT: case OMP_CLAUSE_ORDERED: case OMP_CLAUSE_DEFAULT: case OMP_CLAUSE_UNTIED: break; default: gcc_unreachable (); } } return finish_omp_clauses (nreverse (new_clauses)); } /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */ static tree tsubst_copy_asm_operands (tree t, tree args, tsubst_flags_t complain, tree in_decl) { #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl) tree purpose, value, chain; if (t == NULL) return t; if (TREE_CODE (t) != TREE_LIST) return tsubst_copy_and_build (t, args, complain, in_decl, /*function_p=*/false, /*integral_constant_expression_p=*/false); if (t == void_list_node) return t; purpose = TREE_PURPOSE (t); if (purpose) purpose = RECUR (purpose); value = TREE_VALUE (t); if (value && TREE_CODE (value) != LABEL_DECL) value = RECUR (value); chain = TREE_CHAIN (t); if (chain && chain != void_type_node) chain = RECUR (chain); return tree_cons (purpose, value, chain); #undef RECUR } /* Substitute one OMP_FOR iterator. */ static void tsubst_omp_for_iterator (tree t, int i, tree declv, tree initv, tree condv, tree incrv, tree *clauses, tree args, tsubst_flags_t complain, tree in_decl, bool integral_constant_expression_p) { #define RECUR(NODE) \ tsubst_expr ((NODE), args, complain, in_decl, \ integral_constant_expression_p) tree decl, init, cond, incr, auto_node; init = TREE_VEC_ELT (OMP_FOR_INIT (t), i); gcc_assert (TREE_CODE (init) == MODIFY_EXPR); decl = RECUR (TREE_OPERAND (init, 0)); init = TREE_OPERAND (init, 1); auto_node = type_uses_auto (TREE_TYPE (decl)); if (auto_node && init) { tree init_expr = init; if (TREE_CODE (init_expr) == DECL_EXPR) init_expr = DECL_INITIAL (DECL_EXPR_DECL (init_expr)); init_expr = RECUR (init_expr); TREE_TYPE (decl) = do_auto_deduction (TREE_TYPE (decl), init_expr, auto_node); } gcc_assert (!type_dependent_expression_p (decl)); if (!CLASS_TYPE_P (TREE_TYPE (decl))) { cond = RECUR (TREE_VEC_ELT (OMP_FOR_COND (t), i)); incr = TREE_VEC_ELT (OMP_FOR_INCR (t), i); if (TREE_CODE (incr) == MODIFY_EXPR) incr = build_x_modify_expr (RECUR (TREE_OPERAND (incr, 0)), NOP_EXPR, RECUR (TREE_OPERAND (incr, 1)), complain); else incr = RECUR (incr); TREE_VEC_ELT (declv, i) = decl; TREE_VEC_ELT (initv, i) = init; TREE_VEC_ELT (condv, i) = cond; TREE_VEC_ELT (incrv, i) = incr; return; } if (init && TREE_CODE (init) != DECL_EXPR) { tree c; for (c = *clauses; c ; c = OMP_CLAUSE_CHAIN (c)) { if ((OMP_CLAUSE_CODE (c) == OMP_CLAUSE_PRIVATE || OMP_CLAUSE_CODE (c) == OMP_CLAUSE_LASTPRIVATE) && OMP_CLAUSE_DECL (c) == decl) break; else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_FIRSTPRIVATE && OMP_CLAUSE_DECL (c) == decl) error ("iteration variable %qD should not be firstprivate", decl); else if (OMP_CLAUSE_CODE (c) == OMP_CLAUSE_REDUCTION && OMP_CLAUSE_DECL (c) == decl) error ("iteration variable %qD should not be reduction", decl); } if (c == NULL) { c = build_omp_clause (input_location, OMP_CLAUSE_PRIVATE); OMP_CLAUSE_DECL (c) = decl; c = finish_omp_clauses (c); if (c) { OMP_CLAUSE_CHAIN (c) = *clauses; *clauses = c; } } } cond = TREE_VEC_ELT (OMP_FOR_COND (t), i); if (COMPARISON_CLASS_P (cond)) cond = build2 (TREE_CODE (cond), boolean_type_node, RECUR (TREE_OPERAND (cond, 0)), RECUR (TREE_OPERAND (cond, 1))); else cond = RECUR (cond); incr = TREE_VEC_ELT (OMP_FOR_INCR (t), i); switch (TREE_CODE (incr)) { case PREINCREMENT_EXPR: case PREDECREMENT_EXPR: case POSTINCREMENT_EXPR: case POSTDECREMENT_EXPR: incr = build2 (TREE_CODE (incr), TREE_TYPE (decl), RECUR (TREE_OPERAND (incr, 0)), NULL_TREE); break; case MODIFY_EXPR: if (TREE_CODE (TREE_OPERAND (incr, 1)) == PLUS_EXPR || TREE_CODE (TREE_OPERAND (incr, 1)) == MINUS_EXPR) { tree rhs = TREE_OPERAND (incr, 1); incr = build2 (MODIFY_EXPR, TREE_TYPE (decl), RECUR (TREE_OPERAND (incr, 0)), build2 (TREE_CODE (rhs), TREE_TYPE (decl), RECUR (TREE_OPERAND (rhs, 0)), RECUR (TREE_OPERAND (rhs, 1)))); } else incr = RECUR (incr); break; case MODOP_EXPR: if (TREE_CODE (TREE_OPERAND (incr, 1)) == PLUS_EXPR || TREE_CODE (TREE_OPERAND (incr, 1)) == MINUS_EXPR) { tree lhs = RECUR (TREE_OPERAND (incr, 0)); incr = build2 (MODIFY_EXPR, TREE_TYPE (decl), lhs, build2 (TREE_CODE (TREE_OPERAND (incr, 1)), TREE_TYPE (decl), lhs, RECUR (TREE_OPERAND (incr, 2)))); } else if (TREE_CODE (TREE_OPERAND (incr, 1)) == NOP_EXPR && (TREE_CODE (TREE_OPERAND (incr, 2)) == PLUS_EXPR || (TREE_CODE (TREE_OPERAND (incr, 2)) == MINUS_EXPR))) { tree rhs = TREE_OPERAND (incr, 2); incr = build2 (MODIFY_EXPR, TREE_TYPE (decl), RECUR (TREE_OPERAND (incr, 0)), build2 (TREE_CODE (rhs), TREE_TYPE (decl), RECUR (TREE_OPERAND (rhs, 0)), RECUR (TREE_OPERAND (rhs, 1)))); } else incr = RECUR (incr); break; default: incr = RECUR (incr); break; } TREE_VEC_ELT (declv, i) = decl; TREE_VEC_ELT (initv, i) = init; TREE_VEC_ELT (condv, i) = cond; TREE_VEC_ELT (incrv, i) = incr; #undef RECUR } /* Like tsubst_copy for expressions, etc. but also does semantic processing. */ static tree tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl, bool integral_constant_expression_p) { #define RECUR(NODE) \ tsubst_expr ((NODE), args, complain, in_decl, \ integral_constant_expression_p) tree stmt, tmp; if (t == NULL_TREE || t == error_mark_node) return t; if (EXPR_HAS_LOCATION (t)) input_location = EXPR_LOCATION (t); if (STATEMENT_CODE_P (TREE_CODE (t))) current_stmt_tree ()->stmts_are_full_exprs_p = STMT_IS_FULL_EXPR_P (t); switch (TREE_CODE (t)) { case STATEMENT_LIST: { tree_stmt_iterator i; for (i = tsi_start (t); !tsi_end_p (i); tsi_next (&i)) RECUR (tsi_stmt (i)); break; } case CTOR_INITIALIZER: finish_mem_initializers (tsubst_initializer_list (TREE_OPERAND (t, 0), args)); break; case RETURN_EXPR: finish_return_stmt (RECUR (TREE_OPERAND (t, 0))); break; case EXPR_STMT: tmp = RECUR (EXPR_STMT_EXPR (t)); if (EXPR_STMT_STMT_EXPR_RESULT (t)) finish_stmt_expr_expr (tmp, cur_stmt_expr); else finish_expr_stmt (tmp); break; case USING_STMT: do_using_directive (RECUR (USING_STMT_NAMESPACE (t))); break; case DECL_EXPR: { tree decl; tree init; decl = DECL_EXPR_DECL (t); if (TREE_CODE (decl) == LABEL_DECL) finish_label_decl (DECL_NAME (decl)); else if (TREE_CODE (decl) == USING_DECL) { tree scope = USING_DECL_SCOPE (decl); tree name = DECL_NAME (decl); tree decl; scope = RECUR (scope); decl = lookup_qualified_name (scope, name, /*is_type_p=*/false, /*complain=*/false); if (decl == error_mark_node || TREE_CODE (decl) == TREE_LIST) qualified_name_lookup_error (scope, name, decl, input_location); else do_local_using_decl (decl, scope, name); } else { init = DECL_INITIAL (decl); decl = tsubst (decl, args, complain, in_decl); if (decl != error_mark_node) { /* By marking the declaration as instantiated, we avoid trying to instantiate it. Since instantiate_decl can't handle local variables, and since we've already done all that needs to be done, that's the right thing to do. */ if (TREE_CODE (decl) == VAR_DECL) DECL_TEMPLATE_INSTANTIATED (decl) = 1; if (TREE_CODE (decl) == VAR_DECL && ANON_AGGR_TYPE_P (TREE_TYPE (decl))) /* Anonymous aggregates are a special case. */ finish_anon_union (decl); else { maybe_push_decl (decl); if (TREE_CODE (decl) == VAR_DECL && DECL_PRETTY_FUNCTION_P (decl)) { /* For __PRETTY_FUNCTION__ we have to adjust the initializer. */ const char *const name = cxx_printable_name (current_function_decl, 2); init = cp_fname_init (name, &TREE_TYPE (decl)); } else { tree t = RECUR (init); if (init && !t) /* If we had an initializer but it instantiated to nothing, value-initialize the object. This will only occur when the initializer was a pack expansion where the parameter packs used in that expansion were of length zero. */ init = build_value_init (TREE_TYPE (decl)); else init = t; } cp_finish_decl (decl, init, false, NULL_TREE, 0); } } } /* A DECL_EXPR can also be used as an expression, in the condition clause of an if/for/while construct. */ return decl; } case FOR_STMT: stmt = begin_for_stmt (); RECUR (FOR_INIT_STMT (t)); finish_for_init_stmt (stmt); tmp = RECUR (FOR_COND (t)); finish_for_cond (tmp, stmt); tmp = RECUR (FOR_EXPR (t)); finish_for_expr (tmp, stmt); RECUR (FOR_BODY (t)); finish_for_stmt (stmt); break; case WHILE_STMT: stmt = begin_while_stmt (); tmp = RECUR (WHILE_COND (t)); finish_while_stmt_cond (tmp, stmt); RECUR (WHILE_BODY (t)); finish_while_stmt (stmt); break; case DO_STMT: stmt = begin_do_stmt (); RECUR (DO_BODY (t)); finish_do_body (stmt); tmp = RECUR (DO_COND (t)); finish_do_stmt (tmp, stmt); break; case IF_STMT: stmt = begin_if_stmt (); tmp = RECUR (IF_COND (t)); finish_if_stmt_cond (tmp, stmt); RECUR (THEN_CLAUSE (t)); finish_then_clause (stmt); if (ELSE_CLAUSE (t)) { begin_else_clause (stmt); RECUR (ELSE_CLAUSE (t)); finish_else_clause (stmt); } finish_if_stmt (stmt); break; case BIND_EXPR: if (BIND_EXPR_BODY_BLOCK (t)) stmt = begin_function_body (); else stmt = begin_compound_stmt (BIND_EXPR_TRY_BLOCK (t) ? BCS_TRY_BLOCK : 0); RECUR (BIND_EXPR_BODY (t)); if (BIND_EXPR_BODY_BLOCK (t)) finish_function_body (stmt); else finish_compound_stmt (stmt); break; case BREAK_STMT: finish_break_stmt (); break; case CONTINUE_STMT: finish_continue_stmt (); break; case SWITCH_STMT: stmt = begin_switch_stmt (); tmp = RECUR (SWITCH_STMT_COND (t)); finish_switch_cond (tmp, stmt); RECUR (SWITCH_STMT_BODY (t)); finish_switch_stmt (stmt); break; case CASE_LABEL_EXPR: finish_case_label (EXPR_LOCATION (t), RECUR (CASE_LOW (t)), RECUR (CASE_HIGH (t))); break; case LABEL_EXPR: { tree decl = LABEL_EXPR_LABEL (t); tree label; label = finish_label_stmt (DECL_NAME (decl)); if (DECL_ATTRIBUTES (decl) != NULL_TREE) cplus_decl_attributes (&label, DECL_ATTRIBUTES (decl), 0); } break; case GOTO_EXPR: tmp = GOTO_DESTINATION (t); if (TREE_CODE (tmp) != LABEL_DECL) /* Computed goto's must be tsubst'd into. On the other hand, non-computed gotos must not be; the identifier in question will have no binding. */ tmp = RECUR (tmp); else tmp = DECL_NAME (tmp); finish_goto_stmt (tmp); break; case ASM_EXPR: tmp = finish_asm_stmt (ASM_VOLATILE_P (t), RECUR (ASM_STRING (t)), tsubst_copy_asm_operands (ASM_OUTPUTS (t), args, complain, in_decl), tsubst_copy_asm_operands (ASM_INPUTS (t), args, complain, in_decl), tsubst_copy_asm_operands (ASM_CLOBBERS (t), args, complain, in_decl), tsubst_copy_asm_operands (ASM_LABELS (t), args, complain, in_decl)); { tree asm_expr = tmp; if (TREE_CODE (asm_expr) == CLEANUP_POINT_EXPR) asm_expr = TREE_OPERAND (asm_expr, 0); ASM_INPUT_P (asm_expr) = ASM_INPUT_P (t); } break; case TRY_BLOCK: if (CLEANUP_P (t)) { stmt = begin_try_block (); RECUR (TRY_STMTS (t)); finish_cleanup_try_block (stmt); finish_cleanup (RECUR (TRY_HANDLERS (t)), stmt); } else { tree compound_stmt = NULL_TREE; if (FN_TRY_BLOCK_P (t)) stmt = begin_function_try_block (&compound_stmt); else stmt = begin_try_block (); RECUR (TRY_STMTS (t)); if (FN_TRY_BLOCK_P (t)) finish_function_try_block (stmt); else finish_try_block (stmt); RECUR (TRY_HANDLERS (t)); if (FN_TRY_BLOCK_P (t)) finish_function_handler_sequence (stmt, compound_stmt); else finish_handler_sequence (stmt); } break; case HANDLER: { tree decl = HANDLER_PARMS (t); if (decl) { decl = tsubst (decl, args, complain, in_decl); /* Prevent instantiate_decl from trying to instantiate this variable. We've already done all that needs to be done. */ if (decl != error_mark_node) DECL_TEMPLATE_INSTANTIATED (decl) = 1; } stmt = begin_handler (); finish_handler_parms (decl, stmt); RECUR (HANDLER_BODY (t)); finish_handler (stmt); } break; case TAG_DEFN: tsubst (TREE_TYPE (t), args, complain, NULL_TREE); break; case STATIC_ASSERT: { tree condition = tsubst_expr (STATIC_ASSERT_CONDITION (t), args, complain, in_decl, /*integral_constant_expression_p=*/true); finish_static_assert (condition, STATIC_ASSERT_MESSAGE (t), STATIC_ASSERT_SOURCE_LOCATION (t), /*member_p=*/false); } break; case OMP_PARALLEL: tmp = tsubst_omp_clauses (OMP_PARALLEL_CLAUSES (t), args, complain, in_decl); stmt = begin_omp_parallel (); RECUR (OMP_PARALLEL_BODY (t)); OMP_PARALLEL_COMBINED (finish_omp_parallel (tmp, stmt)) = OMP_PARALLEL_COMBINED (t); break; case OMP_TASK: tmp = tsubst_omp_clauses (OMP_TASK_CLAUSES (t), args, complain, in_decl); stmt = begin_omp_task (); RECUR (OMP_TASK_BODY (t)); finish_omp_task (tmp, stmt); break; case OMP_FOR: { tree clauses, body, pre_body; tree declv, initv, condv, incrv; int i; clauses = tsubst_omp_clauses (OMP_FOR_CLAUSES (t), args, complain, in_decl); declv = make_tree_vec (TREE_VEC_LENGTH (OMP_FOR_INIT (t))); initv = make_tree_vec (TREE_VEC_LENGTH (OMP_FOR_INIT (t))); condv = make_tree_vec (TREE_VEC_LENGTH (OMP_FOR_INIT (t))); incrv = make_tree_vec (TREE_VEC_LENGTH (OMP_FOR_INIT (t))); for (i = 0; i < TREE_VEC_LENGTH (OMP_FOR_INIT (t)); i++) tsubst_omp_for_iterator (t, i, declv, initv, condv, incrv, &clauses, args, complain, in_decl, integral_constant_expression_p); stmt = begin_omp_structured_block (); for (i = 0; i < TREE_VEC_LENGTH (initv); i++) if (TREE_VEC_ELT (initv, i) == NULL || TREE_CODE (TREE_VEC_ELT (initv, i)) != DECL_EXPR) TREE_VEC_ELT (initv, i) = RECUR (TREE_VEC_ELT (initv, i)); else if (CLASS_TYPE_P (TREE_TYPE (TREE_VEC_ELT (initv, i)))) { tree init = RECUR (TREE_VEC_ELT (initv, i)); gcc_assert (init == TREE_VEC_ELT (declv, i)); TREE_VEC_ELT (initv, i) = NULL_TREE; } else { tree decl_expr = TREE_VEC_ELT (initv, i); tree init = DECL_INITIAL (DECL_EXPR_DECL (decl_expr)); gcc_assert (init != NULL); TREE_VEC_ELT (initv, i) = RECUR (init); DECL_INITIAL (DECL_EXPR_DECL (decl_expr)) = NULL; RECUR (decl_expr); DECL_INITIAL (DECL_EXPR_DECL (decl_expr)) = init; } pre_body = push_stmt_list (); RECUR (OMP_FOR_PRE_BODY (t)); pre_body = pop_stmt_list (pre_body); body = push_stmt_list (); RECUR (OMP_FOR_BODY (t)); body = pop_stmt_list (body); t = finish_omp_for (EXPR_LOCATION (t), declv, initv, condv, incrv, body, pre_body, clauses); add_stmt (finish_omp_structured_block (stmt)); } break; case OMP_SECTIONS: case OMP_SINGLE: tmp = tsubst_omp_clauses (OMP_CLAUSES (t), args, complain, in_decl); stmt = push_stmt_list (); RECUR (OMP_BODY (t)); stmt = pop_stmt_list (stmt); t = copy_node (t); OMP_BODY (t) = stmt; OMP_CLAUSES (t) = tmp; add_stmt (t); break; case OMP_SECTION: case OMP_CRITICAL: case OMP_MASTER: case OMP_ORDERED: stmt = push_stmt_list (); RECUR (OMP_BODY (t)); stmt = pop_stmt_list (stmt); t = copy_node (t); OMP_BODY (t) = stmt; add_stmt (t); break; case OMP_ATOMIC: gcc_assert (OMP_ATOMIC_DEPENDENT_P (t)); { tree op1 = TREE_OPERAND (t, 1); tree lhs = RECUR (TREE_OPERAND (op1, 0)); tree rhs = RECUR (TREE_OPERAND (op1, 1)); finish_omp_atomic (TREE_CODE (op1), lhs, rhs); } break; case EXPR_PACK_EXPANSION: error ("invalid use of pack expansion expression"); return error_mark_node; case NONTYPE_ARGUMENT_PACK: error ("use %<...%> to expand argument pack"); return error_mark_node; default: gcc_assert (!STATEMENT_CODE_P (TREE_CODE (t))); return tsubst_copy_and_build (t, args, complain, in_decl, /*function_p=*/false, integral_constant_expression_p); } return NULL_TREE; #undef RECUR } /* T is a postfix-expression that is not being used in a function call. Return the substituted version of T. */ static tree tsubst_non_call_postfix_expression (tree t, tree args, tsubst_flags_t complain, tree in_decl) { if (TREE_CODE (t) == SCOPE_REF) t = tsubst_qualified_id (t, args, complain, in_decl, /*done=*/false, /*address_p=*/false); else t = tsubst_copy_and_build (t, args, complain, in_decl, /*function_p=*/false, /*integral_constant_expression_p=*/false); return t; } /* Like tsubst but deals with expressions and performs semantic analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */ tree tsubst_copy_and_build (tree t, tree args, tsubst_flags_t complain, tree in_decl, bool function_p, bool integral_constant_expression_p) { #define RECUR(NODE) \ tsubst_copy_and_build (NODE, args, complain, in_decl, \ /*function_p=*/false, \ integral_constant_expression_p) tree op1; if (t == NULL_TREE || t == error_mark_node) return t; switch (TREE_CODE (t)) { case USING_DECL: t = DECL_NAME (t); /* Fall through. */ case IDENTIFIER_NODE: { tree decl; cp_id_kind idk; bool non_integral_constant_expression_p; const char *error_msg; if (IDENTIFIER_TYPENAME_P (t)) { tree new_type = tsubst (TREE_TYPE (t), args, complain, in_decl); t = mangle_conv_op_name_for_type (new_type); } /* Look up the name. */ decl = lookup_name (t); /* By convention, expressions use ERROR_MARK_NODE to indicate failure, not NULL_TREE. */ if (decl == NULL_TREE) decl = error_mark_node; decl = finish_id_expression (t, decl, NULL_TREE, &idk, integral_constant_expression_p, /*allow_non_integral_constant_expression_p=*/false, &non_integral_constant_expression_p, /*template_p=*/false, /*done=*/true, /*address_p=*/false, /*template_arg_p=*/false, &error_msg, input_location); if (error_msg) error (error_msg); if (!function_p && TREE_CODE (decl) == IDENTIFIER_NODE) decl = unqualified_name_lookup_error (decl); return decl; } case TEMPLATE_ID_EXPR: { tree object; tree templ = RECUR (TREE_OPERAND (t, 0)); tree targs = TREE_OPERAND (t, 1); if (targs) targs = tsubst_template_args (targs, args, complain, in_decl); if (TREE_CODE (templ) == COMPONENT_REF) { object = TREE_OPERAND (templ, 0); templ = TREE_OPERAND (templ, 1); } else object = NULL_TREE; templ = lookup_template_function (templ, targs); if (object) return build3 (COMPONENT_REF, TREE_TYPE (templ), object, templ, NULL_TREE); else return baselink_for_fns (templ); } case INDIRECT_REF: { tree r = RECUR (TREE_OPERAND (t, 0)); if (REFERENCE_REF_P (t)) { /* A type conversion to reference type will be enclosed in such an indirect ref, but the substitution of the cast will have also added such an indirect ref. */ if (TREE_CODE (TREE_TYPE (r)) == REFERENCE_TYPE) r = convert_from_reference (r); } else r = build_x_indirect_ref (r, RO_UNARY_STAR, complain); return r; } case NOP_EXPR: return build_nop (tsubst (TREE_TYPE (t), args, complain, in_decl), RECUR (TREE_OPERAND (t, 0))); case CAST_EXPR: case REINTERPRET_CAST_EXPR: case CONST_CAST_EXPR: case DYNAMIC_CAST_EXPR: case STATIC_CAST_EXPR: { tree type; tree op; type = tsubst (TREE_TYPE (t), args, complain, in_decl); if (integral_constant_expression_p && !cast_valid_in_integral_constant_expression_p (type)) { if (complain & tf_error) error ("a cast to a type other than an integral or " "enumeration type cannot appear in a constant-expression"); return error_mark_node; } op = RECUR (TREE_OPERAND (t, 0)); switch (TREE_CODE (t)) { case CAST_EXPR: return build_functional_cast (type, op, complain); case REINTERPRET_CAST_EXPR: return build_reinterpret_cast (type, op, complain); case CONST_CAST_EXPR: return build_const_cast (type, op, complain); case DYNAMIC_CAST_EXPR: return build_dynamic_cast (type, op, complain); case STATIC_CAST_EXPR: return build_static_cast (type, op, complain); default: gcc_unreachable (); } } case POSTDECREMENT_EXPR: case POSTINCREMENT_EXPR: op1 = tsubst_non_call_postfix_expression (TREE_OPERAND (t, 0), args, complain, in_decl); return build_x_unary_op (TREE_CODE (t), op1, complain); case PREDECREMENT_EXPR: case PREINCREMENT_EXPR: case NEGATE_EXPR: case BIT_NOT_EXPR: case ABS_EXPR: case TRUTH_NOT_EXPR: case UNARY_PLUS_EXPR: /* Unary + */ case REALPART_EXPR: case IMAGPART_EXPR: return build_x_unary_op (TREE_CODE (t), RECUR (TREE_OPERAND (t, 0)), complain); case ADDR_EXPR: op1 = TREE_OPERAND (t, 0); if (TREE_CODE (op1) == SCOPE_REF) op1 = tsubst_qualified_id (op1, args, complain, in_decl, /*done=*/true, /*address_p=*/true); else op1 = tsubst_non_call_postfix_expression (op1, args, complain, in_decl); if (TREE_CODE (op1) == LABEL_DECL) return finish_label_address_expr (DECL_NAME (op1), EXPR_LOCATION (op1)); return build_x_unary_op (ADDR_EXPR, op1, complain); case PLUS_EXPR: case MINUS_EXPR: case MULT_EXPR: case TRUNC_DIV_EXPR: case CEIL_DIV_EXPR: case FLOOR_DIV_EXPR: case ROUND_DIV_EXPR: case EXACT_DIV_EXPR: case BIT_AND_EXPR: case BIT_IOR_EXPR: case BIT_XOR_EXPR: case TRUNC_MOD_EXPR: case FLOOR_MOD_EXPR: case TRUTH_ANDIF_EXPR: case TRUTH_ORIF_EXPR: case TRUTH_AND_EXPR: case TRUTH_OR_EXPR: case RSHIFT_EXPR: case LSHIFT_EXPR: case RROTATE_EXPR: case LROTATE_EXPR: case EQ_EXPR: case NE_EXPR: case MAX_EXPR: case MIN_EXPR: case LE_EXPR: case GE_EXPR: case LT_EXPR: case GT_EXPR: case MEMBER_REF: case DOTSTAR_EXPR: return build_x_binary_op (TREE_CODE (t), RECUR (TREE_OPERAND (t, 0)), (TREE_NO_WARNING (TREE_OPERAND (t, 0)) ? ERROR_MARK : TREE_CODE (TREE_OPERAND (t, 0))), RECUR (TREE_OPERAND (t, 1)), (TREE_NO_WARNING (TREE_OPERAND (t, 1)) ? ERROR_MARK : TREE_CODE (TREE_OPERAND (t, 1))), /*overloaded_p=*/NULL, complain); case SCOPE_REF: return tsubst_qualified_id (t, args, complain, in_decl, /*done=*/true, /*address_p=*/false); case ARRAY_REF: op1 = tsubst_non_call_postfix_expression (TREE_OPERAND (t, 0), args, complain, in_decl); return build_x_array_ref (op1, RECUR (TREE_OPERAND (t, 1)), complain); case SIZEOF_EXPR: if (PACK_EXPANSION_P (TREE_OPERAND (t, 0))) return tsubst_copy (t, args, complain, in_decl); /* Fall through */ case ALIGNOF_EXPR: op1 = TREE_OPERAND (t, 0); if (!args) { /* When there are no ARGS, we are trying to evaluate a non-dependent expression from the parser. Trying to do the substitutions may not work. */ if (!TYPE_P (op1)) op1 = TREE_TYPE (op1); } else { ++cp_unevaluated_operand; ++c_inhibit_evaluation_warnings; op1 = tsubst_copy_and_build (op1, args, complain, in_decl, /*function_p=*/false, /*integral_constant_expression_p=*/false); --cp_unevaluated_operand; --c_inhibit_evaluation_warnings; } if (TYPE_P (op1)) return cxx_sizeof_or_alignof_type (op1, TREE_CODE (t), complain & tf_error); else return cxx_sizeof_or_alignof_expr (op1, TREE_CODE (t), complain & tf_error); case MODOP_EXPR: { tree r = build_x_modify_expr (RECUR (TREE_OPERAND (t, 0)), TREE_CODE (TREE_OPERAND (t, 1)), RECUR (TREE_OPERAND (t, 2)), complain); /* TREE_NO_WARNING must be set if either the expression was parenthesized or it uses an operator such as >>= rather than plain assignment. In the former case, it was already set and must be copied. In the latter case, build_x_modify_expr sets it and it must not be reset here. */ if (TREE_NO_WARNING (t)) TREE_NO_WARNING (r) = TREE_NO_WARNING (t); return r; } case ARROW_EXPR: op1 = tsubst_non_call_postfix_expression (TREE_OPERAND (t, 0), args, complain, in_decl); /* Remember that there was a reference to this entity. */ if (DECL_P (op1)) mark_used (op1); return build_x_arrow (op1); case NEW_EXPR: { tree placement = RECUR (TREE_OPERAND (t, 0)); tree init = RECUR (TREE_OPERAND (t, 3)); VEC(tree,gc) *placement_vec; VEC(tree,gc) *init_vec; tree ret; if (placement == NULL_TREE) placement_vec = NULL; else { placement_vec = make_tree_vector (); for (; placement != NULL_TREE; placement = TREE_CHAIN (placement)) VEC_safe_push (tree, gc, placement_vec, TREE_VALUE (placement)); } /* If there was an initializer in the original tree, but it instantiated to an empty list, then we should pass a non-NULL empty vector to tell build_new that it was an empty initializer() rather than no initializer. This can only happen when the initializer is a pack expansion whose parameter packs are of length zero. */ if (init == NULL_TREE && TREE_OPERAND (t, 3) == NULL_TREE) init_vec = NULL; else { init_vec = make_tree_vector (); if (init == void_zero_node) gcc_assert (init_vec != NULL); else { for (; init != NULL_TREE; init = TREE_CHAIN (init)) VEC_safe_push (tree, gc, init_vec, TREE_VALUE (init)); } } ret = build_new (&placement_vec, RECUR (TREE_OPERAND (t, 1)), RECUR (TREE_OPERAND (t, 2)), &init_vec, NEW_EXPR_USE_GLOBAL (t), complain); if (placement_vec != NULL) release_tree_vector (placement_vec); if (init_vec != NULL) release_tree_vector (init_vec); return ret; } case DELETE_EXPR: return delete_sanity (RECUR (TREE_OPERAND (t, 0)), RECUR (TREE_OPERAND (t, 1)), DELETE_EXPR_USE_VEC (t), DELETE_EXPR_USE_GLOBAL (t)); case COMPOUND_EXPR: return build_x_compound_expr (RECUR (TREE_OPERAND (t, 0)), RECUR (TREE_OPERAND (t, 1)), complain); case CALL_EXPR: { tree function; VEC(tree,gc) *call_args; unsigned int nargs, i; bool qualified_p; bool koenig_p; tree ret; function = CALL_EXPR_FN (t); /* When we parsed the expression, we determined whether or not Koenig lookup should be performed. */ koenig_p = KOENIG_LOOKUP_P (t); if (TREE_CODE (function) == SCOPE_REF) { qualified_p = true; function = tsubst_qualified_id (function, args, complain, in_decl, /*done=*/false, /*address_p=*/false); } else { if (TREE_CODE (function) == COMPONENT_REF) { tree op = TREE_OPERAND (function, 1); qualified_p = (TREE_CODE (op) == SCOPE_REF || (BASELINK_P (op) && BASELINK_QUALIFIED_P (op))); } else qualified_p = false; function = tsubst_copy_and_build (function, args, complain, in_decl, !qualified_p, integral_constant_expression_p); if (BASELINK_P (function)) qualified_p = true; } nargs = call_expr_nargs (t); call_args = make_tree_vector (); for (i = 0; i < nargs; ++i) { tree arg = CALL_EXPR_ARG (t, i); if (!PACK_EXPANSION_P (arg)) VEC_safe_push (tree, gc, call_args, RECUR (CALL_EXPR_ARG (t, i))); else { /* Expand the pack expansion and push each entry onto CALL_ARGS. */ arg = tsubst_pack_expansion (arg, args, complain, in_decl); if (TREE_CODE (arg) == TREE_VEC) { unsigned int len, j; len = TREE_VEC_LENGTH (arg); for (j = 0; j < len; ++j) { tree value = TREE_VEC_ELT (arg, j); if (value != NULL_TREE) value = convert_from_reference (value); VEC_safe_push (tree, gc, call_args, value); } } else { /* A partial substitution. Add one entry. */ VEC_safe_push (tree, gc, call_args, arg); } } } /* We do not perform argument-dependent lookup if normal lookup finds a non-function, in accordance with the expected resolution of DR 218. */ if (koenig_p && ((is_overloaded_fn (function) /* If lookup found a member function, the Koenig lookup is not appropriate, even if an unqualified-name was used to denote the function. */ && !DECL_FUNCTION_MEMBER_P (get_first_fn (function))) || TREE_CODE (function) == IDENTIFIER_NODE) /* Only do this when substitution turns a dependent call into a non-dependent call. */ && type_dependent_expression_p_push (t) && !any_type_dependent_arguments_p (call_args)) function = perform_koenig_lookup (function, call_args); if (TREE_CODE (function) == IDENTIFIER_NODE) { unqualified_name_lookup_error (function); release_tree_vector (call_args); return error_mark_node; } /* Remember that there was a reference to this entity. */ if (DECL_P (function)) mark_used (function); if (TREE_CODE (function) == OFFSET_REF) ret = build_offset_ref_call_from_tree (function, &call_args); else if (TREE_CODE (function) == COMPONENT_REF) { if (!BASELINK_P (TREE_OPERAND (function, 1))) ret = finish_call_expr (function, &call_args, /*disallow_virtual=*/false, /*koenig_p=*/false, complain); else ret = (build_new_method_call (TREE_OPERAND (function, 0), TREE_OPERAND (function, 1), &call_args, NULL_TREE, qualified_p ? LOOKUP_NONVIRTUAL : LOOKUP_NORMAL, /*fn_p=*/NULL, complain)); } else ret = finish_call_expr (function, &call_args, /*disallow_virtual=*/qualified_p, koenig_p, complain); release_tree_vector (call_args); return ret; } case COND_EXPR: return build_x_conditional_expr (RECUR (TREE_OPERAND (t, 0)), RECUR (TREE_OPERAND (t, 1)), RECUR (TREE_OPERAND (t, 2)), complain); case PSEUDO_DTOR_EXPR: return finish_pseudo_destructor_expr (RECUR (TREE_OPERAND (t, 0)), RECUR (TREE_OPERAND (t, 1)), RECUR (TREE_OPERAND (t, 2))); case TREE_LIST: { tree purpose, value, chain; if (t == void_list_node) return t; if ((TREE_PURPOSE (t) && PACK_EXPANSION_P (TREE_PURPOSE (t))) || (TREE_VALUE (t) && PACK_EXPANSION_P (TREE_VALUE (t)))) { /* We have pack expansions, so expand those and create a new list out of it. */ tree purposevec = NULL_TREE; tree valuevec = NULL_TREE; tree chain; int i, len = -1; /* Expand the argument expressions. */ if (TREE_PURPOSE (t)) purposevec = tsubst_pack_expansion (TREE_PURPOSE (t), args, complain, in_decl); if (TREE_VALUE (t)) valuevec = tsubst_pack_expansion (TREE_VALUE (t), args, complain, in_decl); /* Build the rest of the list. */ chain = TREE_CHAIN (t); if (chain && chain != void_type_node) chain = RECUR (chain); /* Determine the number of arguments. */ if (purposevec && TREE_CODE (purposevec) == TREE_VEC) { len = TREE_VEC_LENGTH (purposevec); gcc_assert (!valuevec || len == TREE_VEC_LENGTH (valuevec)); } else if (TREE_CODE (valuevec) == TREE_VEC) len = TREE_VEC_LENGTH (valuevec); else { /* Since we only performed a partial substitution into the argument pack, we only return a single list node. */ if (purposevec == TREE_PURPOSE (t) && valuevec == TREE_VALUE (t) && chain == TREE_CHAIN (t)) return t; return tree_cons (purposevec, valuevec, chain); } /* Convert the argument vectors into a TREE_LIST */ i = len; while (i > 0) { /* Grab the Ith values. */ i--; purpose = purposevec ? TREE_VEC_ELT (purposevec, i) : NULL_TREE; value = valuevec ? convert_from_reference (TREE_VEC_ELT (valuevec, i)) : NULL_TREE; /* Build the list (backwards). */ chain = tree_cons (purpose, value, chain); } return chain; } purpose = TREE_PURPOSE (t); if (purpose) purpose = RECUR (purpose); value = TREE_VALUE (t); if (value) value = RECUR (value); chain = TREE_CHAIN (t); if (chain && chain != void_type_node) chain = RECUR (chain); if (purpose == TREE_PURPOSE (t) && value == TREE_VALUE (t) && chain == TREE_CHAIN (t)) return t; return tree_cons (purpose, value, chain); } case COMPONENT_REF: { tree object; tree object_type; tree member; object = tsubst_non_call_postfix_expression (TREE_OPERAND (t, 0), args, complain, in_decl); /* Remember that there was a reference to this entity. */ if (DECL_P (object)) mark_used (object); object_type = TREE_TYPE (object); member = TREE_OPERAND (t, 1); if (BASELINK_P (member)) member = tsubst_baselink (member, non_reference (TREE_TYPE (object)), args, complain, in_decl); else member = tsubst_copy (member, args, complain, in_decl); if (member == error_mark_node) return error_mark_node; if (object_type && !CLASS_TYPE_P (object_type)) { if (SCALAR_TYPE_P (object_type)) { tree s = NULL_TREE; tree dtor = member; if (TREE_CODE (dtor) == SCOPE_REF) { s = TREE_OPERAND (dtor, 0); dtor = TREE_OPERAND (dtor, 1); } if (TREE_CODE (dtor) == BIT_NOT_EXPR) { dtor = TREE_OPERAND (dtor, 0); if (TYPE_P (dtor)) return finish_pseudo_destructor_expr (object, s, dtor); } } } else if (TREE_CODE (member) == SCOPE_REF && TREE_CODE (TREE_OPERAND (member, 1)) == TEMPLATE_ID_EXPR) { tree tmpl; tree args; /* Lookup the template functions now that we know what the scope is. */ tmpl = TREE_OPERAND (TREE_OPERAND (member, 1), 0); args = TREE_OPERAND (TREE_OPERAND (member, 1), 1); member = lookup_qualified_name (TREE_OPERAND (member, 0), tmpl, /*is_type_p=*/false, /*complain=*/false); if (BASELINK_P (member)) { BASELINK_FUNCTIONS (member) = build_nt (TEMPLATE_ID_EXPR, BASELINK_FUNCTIONS (member), args); member = (adjust_result_of_qualified_name_lookup (member, BINFO_TYPE (BASELINK_BINFO (member)), object_type)); } else { qualified_name_lookup_error (object_type, tmpl, member, input_location); return error_mark_node; } } else if (TREE_CODE (member) == SCOPE_REF && !CLASS_TYPE_P (TREE_OPERAND (member, 0)) && TREE_CODE (TREE_OPERAND (member, 0)) != NAMESPACE_DECL) { if (complain & tf_error) { if (TYPE_P (TREE_OPERAND (member, 0))) error ("%qT is not a class or namespace", TREE_OPERAND (member, 0)); else error ("%qD is not a class or namespace", TREE_OPERAND (member, 0)); } return error_mark_node; } else if (TREE_CODE (member) == FIELD_DECL) return finish_non_static_data_member (member, object, NULL_TREE); return finish_class_member_access_expr (object, member, /*template_p=*/false, complain); } case THROW_EXPR: return build_throw (RECUR (TREE_OPERAND (t, 0))); case CONSTRUCTOR: { VEC(constructor_elt,gc) *n; constructor_elt *ce; unsigned HOST_WIDE_INT idx; tree type = tsubst (TREE_TYPE (t), args, complain, in_decl); bool process_index_p; int newlen; bool need_copy_p = false; tree r; if (type == error_mark_node) return error_mark_node; /* digest_init will do the wrong thing if we let it. */ if (type && TYPE_PTRMEMFUNC_P (type)) return t; /* We do not want to process the index of aggregate initializers as they are identifier nodes which will be looked up by digest_init. */ process_index_p = !(type && MAYBE_CLASS_TYPE_P (type)); n = VEC_copy (constructor_elt, gc, CONSTRUCTOR_ELTS (t)); newlen = VEC_length (constructor_elt, n); for (idx = 0; VEC_iterate (constructor_elt, n, idx, ce); idx++) { if (ce->index && process_index_p) ce->index = RECUR (ce->index); if (PACK_EXPANSION_P (ce->value)) { /* Substitute into the pack expansion. */ ce->value = tsubst_pack_expansion (ce->value, args, complain, in_decl); if (ce->value == error_mark_node) ; else if (TREE_VEC_LENGTH (ce->value) == 1) /* Just move the argument into place. */ ce->value = TREE_VEC_ELT (ce->value, 0); else { /* Update the length of the final CONSTRUCTOR arguments vector, and note that we will need to copy.*/ newlen = newlen + TREE_VEC_LENGTH (ce->value) - 1; need_copy_p = true; } } else ce->value = RECUR (ce->value); } if (need_copy_p) { VEC(constructor_elt,gc) *old_n = n; n = VEC_alloc (constructor_elt, gc, newlen); for (idx = 0; VEC_iterate (constructor_elt, old_n, idx, ce); idx++) { if (TREE_CODE (ce->value) == TREE_VEC) { int i, len = TREE_VEC_LENGTH (ce->value); for (i = 0; i < len; ++i) CONSTRUCTOR_APPEND_ELT (n, 0, TREE_VEC_ELT (ce->value, i)); } else CONSTRUCTOR_APPEND_ELT (n, 0, ce->value); } } r = build_constructor (init_list_type_node, n); CONSTRUCTOR_IS_DIRECT_INIT (r) = CONSTRUCTOR_IS_DIRECT_INIT (t); if (TREE_HAS_CONSTRUCTOR (t)) return finish_compound_literal (type, r); return r; } case TYPEID_EXPR: { tree operand_0 = RECUR (TREE_OPERAND (t, 0)); if (TYPE_P (operand_0)) return get_typeid (operand_0); return build_typeid (operand_0); } case VAR_DECL: if (!args) return t; /* Fall through */ case PARM_DECL: { tree r = tsubst_copy (t, args, complain, in_decl); if (TREE_CODE (TREE_TYPE (t)) != REFERENCE_TYPE) /* If the original type was a reference, we'll be wrapped in the appropriate INDIRECT_REF. */ r = convert_from_reference (r); return r; } case VA_ARG_EXPR: return build_x_va_arg (RECUR (TREE_OPERAND (t, 0)), tsubst_copy (TREE_TYPE (t), args, complain, in_decl)); case OFFSETOF_EXPR: return finish_offsetof (RECUR (TREE_OPERAND (t, 0))); case TRAIT_EXPR: { tree type1 = tsubst_copy (TRAIT_EXPR_TYPE1 (t), args, complain, in_decl); tree type2 = TRAIT_EXPR_TYPE2 (t); if (type2) type2 = tsubst_copy (type2, args, complain, in_decl); return finish_trait_expr (TRAIT_EXPR_KIND (t), type1, type2); } case STMT_EXPR: { tree old_stmt_expr = cur_stmt_expr; tree stmt_expr = begin_stmt_expr (); cur_stmt_expr = stmt_expr; tsubst_expr (STMT_EXPR_STMT (t), args, complain, in_decl, integral_constant_expression_p); stmt_expr = finish_stmt_expr (stmt_expr, false); cur_stmt_expr = old_stmt_expr; /* If the resulting list of expression statement is empty, fold it further into void_zero_node. */ if (empty_expr_stmt_p (stmt_expr)) stmt_expr = void_zero_node; return stmt_expr; } case CONST_DECL: t = tsubst_copy (t, args, complain, in_decl); /* As in finish_id_expression, we resolve enumeration constants to their underlying values. */ if (TREE_CODE (t) == CONST_DECL) { used_types_insert (TREE_TYPE (t)); return DECL_INITIAL (t); } return t; case LAMBDA_EXPR: { tree r = build_lambda_expr (); tree type = tsubst (TREE_TYPE (t), args, complain, NULL_TREE); TREE_TYPE (r) = type; CLASSTYPE_LAMBDA_EXPR (type) = r; LAMBDA_EXPR_LOCATION (r) = LAMBDA_EXPR_LOCATION (t); LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (r) = LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (t); LAMBDA_EXPR_MUTABLE_P (r) = LAMBDA_EXPR_MUTABLE_P (t); LAMBDA_EXPR_DISCRIMINATOR (r) = (LAMBDA_EXPR_DISCRIMINATOR (t)); LAMBDA_EXPR_CAPTURE_LIST (r) = RECUR (LAMBDA_EXPR_CAPTURE_LIST (t)); LAMBDA_EXPR_THIS_CAPTURE (r) = RECUR (LAMBDA_EXPR_THIS_CAPTURE (t)); LAMBDA_EXPR_EXTRA_SCOPE (r) = RECUR (LAMBDA_EXPR_EXTRA_SCOPE (t)); /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */ determine_visibility (TYPE_NAME (type)); /* Now that we know visibility, instantiate the type so we have a declaration of the op() for later calls to lambda_function. */ complete_type (type); type = tsubst (LAMBDA_EXPR_RETURN_TYPE (t), args, complain, in_decl); if (type) apply_lambda_return_type (r, type); return build_lambda_object (r); } default: /* Handle Objective-C++ constructs, if appropriate. */ { tree subst = objcp_tsubst_copy_and_build (t, args, complain, in_decl, /*function_p=*/false); if (subst) return subst; } return tsubst_copy (t, args, complain, in_decl); } #undef RECUR } /* Verify that the instantiated ARGS are valid. For type arguments, make sure that the type's linkage is ok. For non-type arguments, make sure they are constants if they are integral or enumerations. Emit an error under control of COMPLAIN, and return TRUE on error. */ static bool check_instantiated_arg (tree tmpl, tree t, tsubst_flags_t complain) { if (ARGUMENT_PACK_P (t)) { tree vec = ARGUMENT_PACK_ARGS (t); int len = TREE_VEC_LENGTH (vec); bool result = false; int i; for (i = 0; i < len; ++i) if (check_instantiated_arg (tmpl, TREE_VEC_ELT (vec, i), complain)) result = true; return result; } else if (TYPE_P (t)) { /* [basic.link]: A name with no linkage (notably, the name of a class or enumeration declared in a local scope) shall not be used to declare an entity with linkage. This implies that names with no linkage cannot be used as template arguments DR 757 relaxes this restriction for C++0x. */ tree nt = (cxx_dialect > cxx98 ? NULL_TREE : no_linkage_check (t, /*relaxed_p=*/false)); if (nt) { /* DR 488 makes use of a type with no linkage cause type deduction to fail. */ if (complain & tf_error) { if (TYPE_ANONYMOUS_P (nt)) error ("%qT is/uses anonymous type", t); else error ("template argument for %qD uses local type %qT", tmpl, t); } return true; } /* In order to avoid all sorts of complications, we do not allow variably-modified types as template arguments. */ else if (variably_modified_type_p (t, NULL_TREE)) { if (complain & tf_error) error ("%qT is a variably modified type", t); return true; } } /* A non-type argument of integral or enumerated type must be a constant. */ else if (TREE_TYPE (t) && INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (t)) && !TREE_CONSTANT (t)) { if (complain & tf_error) error ("integral expression %qE is not constant", t); return true; } return false; } static bool check_instantiated_args (tree tmpl, tree args, tsubst_flags_t complain) { int ix, len = DECL_NTPARMS (tmpl); bool result = false; for (ix = 0; ix != len; ix++) { if (check_instantiated_arg (tmpl, TREE_VEC_ELT (args, ix), complain)) result = true; } if (result && (complain & tf_error)) error (" trying to instantiate %qD", tmpl); return result; } /* Instantiate the indicated variable or function template TMPL with the template arguments in TARG_PTR. */ tree instantiate_template (tree tmpl, tree orig_args, tsubst_flags_t complain) { tree targ_ptr = orig_args; tree fndecl; tree gen_tmpl; tree spec; HOST_WIDE_INT saved_processing_template_decl; if (tmpl == error_mark_node) return error_mark_node; gcc_assert (TREE_CODE (tmpl) == TEMPLATE_DECL); /* If this function is a clone, handle it specially. */ if (DECL_CLONED_FUNCTION_P (tmpl)) { tree spec; tree clone; /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have DECL_CLONED_FUNCTION. */ spec = instantiate_template (DECL_ABSTRACT_ORIGIN (tmpl), targ_ptr, complain); if (spec == error_mark_node) return error_mark_node; /* Look for the clone. */ FOR_EACH_CLONE (clone, spec) if (DECL_NAME (clone) == DECL_NAME (tmpl)) return clone; /* We should always have found the clone by now. */ gcc_unreachable (); return NULL_TREE; } /* Check to see if we already have this specialization. */ gen_tmpl = most_general_template (tmpl); if (tmpl != gen_tmpl) /* The TMPL is a partial instantiation. To get a full set of arguments we must add the arguments used to perform the partial instantiation. */ targ_ptr = add_outermost_template_args (DECL_TI_ARGS (tmpl), targ_ptr); /* It would be nice to avoid hashing here and then again in tsubst_decl, but it doesn't seem to be on the hot path. */ spec = retrieve_specialization (gen_tmpl, targ_ptr, 0); gcc_assert (tmpl == gen_tmpl || ((fndecl = retrieve_specialization (tmpl, orig_args, 0)) == spec) || fndecl == NULL_TREE); if (spec != NULL_TREE) return spec; if (check_instantiated_args (gen_tmpl, INNERMOST_TEMPLATE_ARGS (targ_ptr), complain)) return error_mark_node; /* We are building a FUNCTION_DECL, during which the access of its parameters and return types have to be checked. However this FUNCTION_DECL which is the desired context for access checking is not built yet. We solve this chicken-and-egg problem by deferring all checks until we have the FUNCTION_DECL. */ push_deferring_access_checks (dk_deferred); /* Although PROCESSING_TEMPLATE_DECL may be true at this point (because, for example, we have encountered a non-dependent function call in the body of a template function and must now determine which of several overloaded functions will be called), within the instantiation itself we are not processing a template. */ saved_processing_template_decl = processing_template_decl; processing_template_decl = 0; /* Substitute template parameters to obtain the specialization. */ fndecl = tsubst (DECL_TEMPLATE_RESULT (gen_tmpl), targ_ptr, complain, gen_tmpl); processing_template_decl = saved_processing_template_decl; if (fndecl == error_mark_node) return error_mark_node; /* Now we know the specialization, compute access previously deferred. */ push_access_scope (fndecl); /* Some typedefs referenced from within the template code need to be access checked at template instantiation time, i.e now. These types were added to the template at parsing time. Let's get those and perfom the acces checks then. */ perform_typedefs_access_check (DECL_TEMPLATE_RESULT (tmpl), targ_ptr); perform_deferred_access_checks (); pop_access_scope (fndecl); pop_deferring_access_checks (); /* The DECL_TI_TEMPLATE should always be the immediate parent template, not the most general template. */ DECL_TI_TEMPLATE (fndecl) = tmpl; /* If we've just instantiated the main entry point for a function, instantiate all the alternate entry points as well. We do this by cloning the instantiation of the main entry point, not by instantiating the template clones. */ if (TREE_CHAIN (gen_tmpl) && DECL_CLONED_FUNCTION_P (TREE_CHAIN (gen_tmpl))) clone_function_decl (fndecl, /*update_method_vec_p=*/0); return fndecl; } /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with NARGS elements of the arguments that are being used when calling it. TARGS is a vector into which the deduced template arguments are placed. Return zero for success, 2 for an incomplete match that doesn't resolve all the types, and 1 for complete failure. An error message will be printed only for an incomplete match. If FN is a conversion operator, or we are trying to produce a specific specialization, RETURN_TYPE is the return type desired. The EXPLICIT_TARGS are explicit template arguments provided via a template-id. The parameter STRICT is one of: DEDUCE_CALL: We are deducing arguments for a function call, as in [temp.deduct.call]. DEDUCE_CONV: We are deducing arguments for a conversion function, as in [temp.deduct.conv]. DEDUCE_EXACT: We are deducing arguments when doing an explicit instantiation as in [temp.explicit], when determining an explicit specialization as in [temp.expl.spec], or when taking the address of a function template, as in [temp.deduct.funcaddr]. */ int fn_type_unification (tree fn, tree explicit_targs, tree targs, const tree *args, unsigned int nargs, tree return_type, unification_kind_t strict, int flags) { tree parms; tree fntype; int result; bool incomplete_argument_packs_p = false; gcc_assert (TREE_CODE (fn) == TEMPLATE_DECL); fntype = TREE_TYPE (fn); if (explicit_targs) { /* [temp.deduct] The specified template arguments must match the template parameters in kind (i.e., type, nontype, template), and there must not be more arguments than there are parameters; otherwise type deduction fails. Nontype arguments must match the types of the corresponding nontype template parameters, or must be convertible to the types of the corresponding nontype parameters as specified in _temp.arg.nontype_, otherwise type deduction fails. All references in the function type of the function template to the corresponding template parameters are replaced by the specified template argument values. If a substitution in a template parameter or in the function type of the function template results in an invalid type, type deduction fails. */ tree tparms = DECL_INNERMOST_TEMPLATE_PARMS (fn); int i, len = TREE_VEC_LENGTH (tparms); tree converted_args; bool incomplete = false; if (explicit_targs == error_mark_node) return 1; converted_args = (coerce_template_parms (tparms, explicit_targs, NULL_TREE, tf_none, /*require_all_args=*/false, /*use_default_args=*/false)); if (converted_args == error_mark_node) return 1; /* Substitute the explicit args into the function type. This is necessary so that, for instance, explicitly declared function arguments can match null pointed constants. If we were given an incomplete set of explicit args, we must not do semantic processing during substitution as we could create partial instantiations. */ for (i = 0; i < len; i++) { tree parm = TREE_VALUE (TREE_VEC_ELT (tparms, i)); bool parameter_pack = false; /* Dig out the actual parm. */ if (TREE_CODE (parm) == TYPE_DECL || TREE_CODE (parm) == TEMPLATE_DECL) { parm = TREE_TYPE (parm); parameter_pack = TEMPLATE_TYPE_PARAMETER_PACK (parm); } else if (TREE_CODE (parm) == PARM_DECL) { parm = DECL_INITIAL (parm); parameter_pack = TEMPLATE_PARM_PARAMETER_PACK (parm); } if (parameter_pack) { int level, idx; tree targ; template_parm_level_and_index (parm, &level, &idx); /* Mark the argument pack as "incomplete". We could still deduce more arguments during unification. */ targ = TMPL_ARG (converted_args, level, idx); if (targ) { ARGUMENT_PACK_INCOMPLETE_P(targ) = 1; ARGUMENT_PACK_EXPLICIT_ARGS (targ) = ARGUMENT_PACK_ARGS (targ); } /* We have some incomplete argument packs. */ incomplete_argument_packs_p = true; } } if (incomplete_argument_packs_p) /* Any substitution is guaranteed to be incomplete if there are incomplete argument packs, because we can still deduce more arguments. */ incomplete = 1; else incomplete = NUM_TMPL_ARGS (explicit_targs) != NUM_TMPL_ARGS (targs); processing_template_decl += incomplete; fntype = tsubst (fntype, converted_args, tf_none, NULL_TREE); processing_template_decl -= incomplete; if (fntype == error_mark_node) return 1; /* Place the explicitly specified arguments in TARGS. */ for (i = NUM_TMPL_ARGS (converted_args); i--;) TREE_VEC_ELT (targs, i) = TREE_VEC_ELT (converted_args, i); } /* Never do unification on the 'this' parameter. */ parms = skip_artificial_parms_for (fn, TYPE_ARG_TYPES (fntype)); if (return_type) { tree *new_args; parms = tree_cons (NULL_TREE, TREE_TYPE (fntype), parms); new_args = XALLOCAVEC (tree, nargs + 1); new_args[0] = return_type; memcpy (new_args + 1, args, nargs * sizeof (tree)); args = new_args; ++nargs; } /* We allow incomplete unification without an error message here because the standard doesn't seem to explicitly prohibit it. Our callers must be ready to deal with unification failures in any event. */ result = type_unification_real (DECL_INNERMOST_TEMPLATE_PARMS (fn), targs, parms, args, nargs, /*subr=*/0, strict, flags); if (result == 0 && incomplete_argument_packs_p) { int i, len = NUM_TMPL_ARGS (targs); /* Clear the "incomplete" flags on all argument packs. */ for (i = 0; i < len; i++) { tree arg = TREE_VEC_ELT (targs, i); if (ARGUMENT_PACK_P (arg)) { ARGUMENT_PACK_INCOMPLETE_P (arg) = 0; ARGUMENT_PACK_EXPLICIT_ARGS (arg) = NULL_TREE; } } } /* Now that we have bindings for all of the template arguments, ensure that the arguments deduced for the template template parameters have compatible template parameter lists. We cannot check this property before we have deduced all template arguments, because the template parameter types of a template template parameter might depend on prior template parameters deduced after the template template parameter. The following ill-formed example illustrates this issue: template<typename T, template<T> class C> void f(C<5>, T); template<int N> struct X {}; void g() { f(X<5>(), 5l); // error: template argument deduction fails } The template parameter list of 'C' depends on the template type parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the time that we deduce 'C'. */ if (result == 0 && !template_template_parm_bindings_ok_p (DECL_INNERMOST_TEMPLATE_PARMS (fn), targs)) return 1; if (result == 0) /* All is well so far. Now, check: [temp.deduct] When all template arguments have been deduced, all uses of template parameters in nondeduced contexts are replaced with the corresponding deduced argument values. If the substitution results in an invalid type, as described above, type deduction fails. */ { tree substed = tsubst (TREE_TYPE (fn), targs, tf_none, NULL_TREE); if (substed == error_mark_node) return 1; /* If we're looking for an exact match, check that what we got is indeed an exact match. It might not be if some template parameters are used in non-deduced contexts. */ if (strict == DEDUCE_EXACT) { unsigned int i; tree sarg = skip_artificial_parms_for (fn, TYPE_ARG_TYPES (substed)); if (return_type) sarg = tree_cons (NULL_TREE, TREE_TYPE (substed), sarg); for (i = 0; i < nargs && sarg; ++i, sarg = TREE_CHAIN (sarg)) if (!same_type_p (args[i], TREE_VALUE (sarg))) return 1; } } return result; } /* Adjust types before performing type deduction, as described in [temp.deduct.call] and [temp.deduct.conv]. The rules in these two sections are symmetric. PARM is the type of a function parameter or the return type of the conversion function. ARG is the type of the argument passed to the call, or the type of the value initialized with the result of the conversion function. ARG_EXPR is the original argument expression, which may be null. */ static int maybe_adjust_types_for_deduction (unification_kind_t strict, tree* parm, tree* arg, tree arg_expr) { int result = 0; switch (strict) { case DEDUCE_CALL: break; case DEDUCE_CONV: { /* Swap PARM and ARG throughout the remainder of this function; the handling is precisely symmetric since PARM will initialize ARG rather than vice versa. */ tree* temp = parm; parm = arg; arg = temp; break; } case DEDUCE_EXACT: /* Core issue #873: Do the DR606 thing (see below) for these cases, too, but here handle it by stripping the reference from PARM rather than by adding it to ARG. */ if (TREE_CODE (*parm) == REFERENCE_TYPE && TYPE_REF_IS_RVALUE (*parm) && TREE_CODE (TREE_TYPE (*parm)) == TEMPLATE_TYPE_PARM && cp_type_quals (TREE_TYPE (*parm)) == TYPE_UNQUALIFIED && TREE_CODE (*arg) == REFERENCE_TYPE && !TYPE_REF_IS_RVALUE (*arg)) *parm = TREE_TYPE (*parm); /* Nothing else to do in this case. */ return 0; default: gcc_unreachable (); } if (TREE_CODE (*parm) != REFERENCE_TYPE) { /* [temp.deduct.call] If P is not a reference type: --If A is an array type, the pointer type produced by the array-to-pointer standard conversion (_conv.array_) is used in place of A for type deduction; otherwise, --If A is a function type, the pointer type produced by the function-to-pointer standard conversion (_conv.func_) is used in place of A for type deduction; otherwise, --If A is a cv-qualified type, the top level cv-qualifiers of A's type are ignored for type deduction. */ if (TREE_CODE (*arg) == ARRAY_TYPE) *arg = build_pointer_type (TREE_TYPE (*arg)); else if (TREE_CODE (*arg) == FUNCTION_TYPE) *arg = build_pointer_type (*arg); else *arg = TYPE_MAIN_VARIANT (*arg); } /* From C++0x [14.8.2.1/3 temp.deduct.call] (after DR606), "If P is of the form T&&, where T is a template parameter, and the argument is an lvalue, T is deduced as A& */ if (TREE_CODE (*parm) == REFERENCE_TYPE && TYPE_REF_IS_RVALUE (*parm) && TREE_CODE (TREE_TYPE (*parm)) == TEMPLATE_TYPE_PARM && cp_type_quals (TREE_TYPE (*parm)) == TYPE_UNQUALIFIED && arg_expr && real_lvalue_p (arg_expr)) *arg = build_reference_type (*arg); /* [temp.deduct.call] If P is a cv-qualified type, the top level cv-qualifiers of P's type are ignored for type deduction. If P is a reference type, the type referred to by P is used for type deduction. */ *parm = TYPE_MAIN_VARIANT (*parm); if (TREE_CODE (*parm) == REFERENCE_TYPE) { *parm = TREE_TYPE (*parm); result |= UNIFY_ALLOW_OUTER_MORE_CV_QUAL; } /* DR 322. For conversion deduction, remove a reference type on parm too (which has been swapped into ARG). */ if (strict == DEDUCE_CONV && TREE_CODE (*arg) == REFERENCE_TYPE) *arg = TREE_TYPE (*arg); return result; } /* Most parms like fn_type_unification. If SUBR is 1, we're being called recursively (to unify the arguments of a function or method parameter of a function template). */ static int type_unification_real (tree tparms, tree targs, tree xparms, const tree *xargs, unsigned int xnargs, int subr, unification_kind_t strict, int flags) { tree parm, arg, arg_expr; int i; int ntparms = TREE_VEC_LENGTH (tparms); int sub_strict; int saw_undeduced = 0; tree parms; const tree *args; unsigned int nargs; unsigned int ia; gcc_assert (TREE_CODE (tparms) == TREE_VEC); gcc_assert (xparms == NULL_TREE || TREE_CODE (xparms) == TREE_LIST); gcc_assert (ntparms > 0); /* Reset the number of non-defaulted template arguments contained in in TARGS. */ NON_DEFAULT_TEMPLATE_ARGS_COUNT (targs) = NULL_TREE; switch (strict) { case DEDUCE_CALL: sub_strict = (UNIFY_ALLOW_OUTER_LEVEL | UNIFY_ALLOW_MORE_CV_QUAL | UNIFY_ALLOW_DERIVED); break; case DEDUCE_CONV: sub_strict = UNIFY_ALLOW_LESS_CV_QUAL; break; case DEDUCE_EXACT: sub_strict = UNIFY_ALLOW_NONE; break; default: gcc_unreachable (); } again: parms = xparms; args = xargs; nargs = xnargs; ia = 0; while (parms && parms != void_list_node && ia < nargs) { if (TREE_CODE (TREE_VALUE (parms)) == TYPE_PACK_EXPANSION) break; parm = TREE_VALUE (parms); parms = TREE_CHAIN (parms); arg = args[ia]; ++ia; arg_expr = NULL; if (arg == error_mark_node) return 1; if (arg == unknown_type_node) /* We can't deduce anything from this, but we might get all the template args from other function args. */ continue; /* Conversions will be performed on a function argument that corresponds with a function parameter that contains only non-deducible template parameters and explicitly specified template parameters. */ if (!uses_template_parms (parm)) { tree type; if (!TYPE_P (arg)) type = TREE_TYPE (arg); else type = arg; if (same_type_p (parm, type)) continue; if (strict != DEDUCE_EXACT && can_convert_arg (parm, type, TYPE_P (arg) ? NULL_TREE : arg, flags)) continue; return 1; } if (!TYPE_P (arg)) { gcc_assert (TREE_TYPE (arg) != NULL_TREE); if (type_unknown_p (arg)) { /* [temp.deduct.type] A template-argument can be deduced from a pointer to function or pointer to member function argument if the set of overloaded functions does not contain function templates and at most one of a set of overloaded functions provides a unique match. */ if (resolve_overloaded_unification (tparms, targs, parm, arg, strict, sub_strict)) continue; return 1; } arg_expr = arg; arg = unlowered_expr_type (arg); if (arg == error_mark_node) return 1; } { int arg_strict = sub_strict; if (!subr) arg_strict |= maybe_adjust_types_for_deduction (strict, &parm, &arg, arg_expr); if (arg == init_list_type_node && arg_expr) arg = arg_expr; if (unify (tparms, targs, parm, arg, arg_strict)) return 1; } } if (parms && parms != void_list_node && TREE_CODE (TREE_VALUE (parms)) == TYPE_PACK_EXPANSION) { /* Unify the remaining arguments with the pack expansion type. */ tree argvec; tree parmvec = make_tree_vec (1); /* Allocate a TREE_VEC and copy in all of the arguments */ argvec = make_tree_vec (nargs - ia); for (i = 0; ia < nargs; ++ia, ++i) TREE_VEC_ELT (argvec, i) = args[ia]; /* Copy the parameter into parmvec. */ TREE_VEC_ELT (parmvec, 0) = TREE_VALUE (parms); if (unify_pack_expansion (tparms, targs, parmvec, argvec, strict, /*call_args_p=*/true, /*subr=*/subr)) return 1; /* Advance to the end of the list of parameters. */ parms = TREE_CHAIN (parms); } /* Fail if we've reached the end of the parm list, and more args are present, and the parm list isn't variadic. */ if (ia < nargs && parms == void_list_node) return 1; /* Fail if parms are left and they don't have default values. */ if (parms && parms != void_list_node && TREE_PURPOSE (parms) == NULL_TREE) return 1; if (!subr) for (i = 0; i < ntparms; i++) if (!TREE_VEC_ELT (targs, i)) { tree tparm; if (TREE_VEC_ELT (tparms, i) == error_mark_node) continue; tparm = TREE_VALUE (TREE_VEC_ELT (tparms, i)); /* If this is an undeduced nontype parameter that depends on a type parameter, try another pass; its type may have been deduced from a later argument than the one from which this parameter can be deduced. */ if (TREE_CODE (tparm) == PARM_DECL && uses_template_parms (TREE_TYPE (tparm)) && !saw_undeduced++) goto again; /* Core issue #226 (C++0x) [temp.deduct]: If a template argument has not been deduced, its default template argument, if any, is used. When we are in C++98 mode, TREE_PURPOSE will either be NULL_TREE or ERROR_MARK_NODE, so we do not need to explicitly check cxx_dialect here. */ if (TREE_PURPOSE (TREE_VEC_ELT (tparms, i))) { tree parm = TREE_VALUE (TREE_VEC_ELT (tparms, i)); tree arg = TREE_PURPOSE (TREE_VEC_ELT (tparms, i)); arg = tsubst_template_arg (arg, targs, tf_none, NULL_TREE); arg = convert_template_argument (parm, arg, targs, tf_none, i, NULL_TREE); if (arg == error_mark_node) return 1; else { TREE_VEC_ELT (targs, i) = arg; /* The position of the first default template argument, is also the number of non-defaulted arguments in TARGS. Record that. */ if (!NON_DEFAULT_TEMPLATE_ARGS_COUNT (targs)) SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (targs, i); continue; } } /* If the type parameter is a parameter pack, then it will be deduced to an empty parameter pack. */ if (template_parameter_pack_p (tparm)) { tree arg; if (TREE_CODE (tparm) == TEMPLATE_PARM_INDEX) { arg = make_node (NONTYPE_ARGUMENT_PACK); TREE_TYPE (arg) = TREE_TYPE (TEMPLATE_PARM_DECL (tparm)); TREE_CONSTANT (arg) = 1; } else arg = cxx_make_type (TYPE_ARGUMENT_PACK); SET_ARGUMENT_PACK_ARGS (arg, make_tree_vec (0)); TREE_VEC_ELT (targs, i) = arg; continue; } return 2; } #ifdef ENABLE_CHECKING if (!NON_DEFAULT_TEMPLATE_ARGS_COUNT (targs)) SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT (targs, TREE_VEC_LENGTH (targs)); #endif return 0; } /* Subroutine of type_unification_real. Args are like the variables at the call site. ARG is an overloaded function (or template-id); we try deducing template args from each of the overloads, and if only one succeeds, we go with that. Modifies TARGS and returns true on success. */ static bool resolve_overloaded_unification (tree tparms, tree targs, tree parm, tree arg, unification_kind_t strict, int sub_strict) { tree tempargs = copy_node (targs); int good = 0; tree goodfn = NULL_TREE; bool addr_p; if (TREE_CODE (arg) == ADDR_EXPR) { arg = TREE_OPERAND (arg, 0); addr_p = true; } else addr_p = false; if (TREE_CODE (arg) == COMPONENT_REF) /* Handle `&x' where `x' is some static or non-static member function name. */ arg = TREE_OPERAND (arg, 1); if (TREE_CODE (arg) == OFFSET_REF) arg = TREE_OPERAND (arg, 1); /* Strip baselink information. */ if (BASELINK_P (arg)) arg = BASELINK_FUNCTIONS (arg); if (TREE_CODE (arg) == TEMPLATE_ID_EXPR) { /* If we got some explicit template args, we need to plug them into the affected templates before we try to unify, in case the explicit args will completely resolve the templates in question. */ tree expl_subargs = TREE_OPERAND (arg, 1); arg = TREE_OPERAND (arg, 0); for (; arg; arg = OVL_NEXT (arg)) { tree fn = OVL_CURRENT (arg); tree subargs, elem; if (TREE_CODE (fn) != TEMPLATE_DECL) continue; ++processing_template_decl; subargs = get_bindings (fn, DECL_TEMPLATE_RESULT (fn), expl_subargs, /*check_ret=*/false); if (subargs) { elem = tsubst (TREE_TYPE (fn), subargs, tf_none, NULL_TREE); if (try_one_overload (tparms, targs, tempargs, parm, elem, strict, sub_strict, addr_p) && (!goodfn || !decls_match (goodfn, elem))) { goodfn = elem; ++good; } } --processing_template_decl; } } else if (TREE_CODE (arg) != OVERLOAD && TREE_CODE (arg) != FUNCTION_DECL) /* If ARG is, for example, "(0, &f)" then its type will be unknown -- but the deduction does not succeed because the expression is not just the function on its own. */ return false; else for (; arg; arg = OVL_NEXT (arg)) if (try_one_overload (tparms, targs, tempargs, parm, TREE_TYPE (OVL_CURRENT (arg)), strict, sub_strict, addr_p) && (!goodfn || !decls_match (goodfn, OVL_CURRENT (arg)))) { goodfn = OVL_CURRENT (arg); ++good; } /* [temp.deduct.type] A template-argument can be deduced from a pointer to function or pointer to member function argument if the set of overloaded functions does not contain function templates and at most one of a set of overloaded functions provides a unique match. So if we found multiple possibilities, we return success but don't deduce anything. */ if (good == 1) { int i = TREE_VEC_LENGTH (targs); for (; i--; ) if (TREE_VEC_ELT (tempargs, i)) TREE_VEC_ELT (targs, i) = TREE_VEC_ELT (tempargs, i); } if (good) return true; return false; } /* Core DR 115: In contexts where deduction is done and fails, or in contexts where deduction is not done, if a template argument list is specified and it, along with any default template arguments, identifies a single function template specialization, then the template-id is an lvalue for the function template specialization. */ tree resolve_nondeduced_context (tree orig_expr) { tree expr, offset, baselink; bool addr; if (!type_unknown_p (orig_expr)) return orig_expr; expr = orig_expr; addr = false; offset = NULL_TREE; baselink = NULL_TREE; if (TREE_CODE (expr) == ADDR_EXPR) { expr = TREE_OPERAND (expr, 0); addr = true; } if (TREE_CODE (expr) == OFFSET_REF) { offset = expr; expr = TREE_OPERAND (expr, 1); } if (TREE_CODE (expr) == BASELINK) { baselink = expr; expr = BASELINK_FUNCTIONS (expr); } if (TREE_CODE (expr) == TEMPLATE_ID_EXPR) { int good = 0; tree goodfn = NULL_TREE; /* If we got some explicit template args, we need to plug them into the affected templates before we try to unify, in case the explicit args will completely resolve the templates in question. */ tree expl_subargs = TREE_OPERAND (expr, 1); tree arg = TREE_OPERAND (expr, 0); tree badfn = NULL_TREE; tree badargs = NULL_TREE; for (; arg; arg = OVL_NEXT (arg)) { tree fn = OVL_CURRENT (arg); tree subargs, elem; if (TREE_CODE (fn) != TEMPLATE_DECL) continue; ++processing_template_decl; subargs = get_bindings (fn, DECL_TEMPLATE_RESULT (fn), expl_subargs, /*check_ret=*/false); if (subargs && !any_dependent_template_arguments_p (subargs)) { elem = instantiate_template (fn, subargs, tf_none); if (elem == error_mark_node) { badfn = fn; badargs = subargs; } else if (elem && (!goodfn || !decls_match (goodfn, elem))) { goodfn = elem; ++good; } } --processing_template_decl; } if (good == 1) { expr = goodfn; if (baselink) expr = build_baselink (BASELINK_BINFO (baselink), BASELINK_ACCESS_BINFO (baselink), expr, BASELINK_OPTYPE (baselink)); if (offset) expr = build2 (OFFSET_REF, TREE_TYPE (expr), TREE_OPERAND (offset, 0), expr); if (addr) expr = build_address (expr); return expr; } else if (good == 0 && badargs) /* There were no good options and at least one bad one, so let the user know what the problem is. */ instantiate_template (badfn, badargs, tf_warning_or_error); } return orig_expr; } /* Subroutine of resolve_overloaded_unification; does deduction for a single overload. Fills TARGS with any deduced arguments, or error_mark_node if different overloads deduce different arguments for a given parm. ADDR_P is true if the expression for which deduction is being performed was of the form "& fn" rather than simply "fn". Returns 1 on success. */ static int try_one_overload (tree tparms, tree orig_targs, tree targs, tree parm, tree arg, unification_kind_t strict, int sub_strict, bool addr_p) { int nargs; tree tempargs; int i; /* [temp.deduct.type] A template-argument can be deduced from a pointer to function or pointer to member function argument if the set of overloaded functions does not contain function templates and at most one of a set of overloaded functions provides a unique match. So if this is a template, just return success. */ if (uses_template_parms (arg)) return 1; if (TREE_CODE (arg) == METHOD_TYPE) arg = build_ptrmemfunc_type (build_pointer_type (arg)); else if (addr_p) arg = build_pointer_type (arg); sub_strict |= maybe_adjust_types_for_deduction (strict, &parm, &arg, NULL); /* We don't copy orig_targs for this because if we have already deduced some template args from previous args, unify would complain when we try to deduce a template parameter for the same argument, even though there isn't really a conflict. */ nargs = TREE_VEC_LENGTH (targs); tempargs = make_tree_vec (nargs); if (unify (tparms, tempargs, parm, arg, sub_strict) != 0) return 0; /* First make sure we didn't deduce anything that conflicts with explicitly specified args. */ for (i = nargs; i--; ) { tree elt = TREE_VEC_ELT (tempargs, i); tree oldelt = TREE_VEC_ELT (orig_targs, i); if (!elt) /*NOP*/; else if (uses_template_parms (elt)) /* Since we're unifying against ourselves, we will fill in template args used in the function parm list with our own template parms. Discard them. */ TREE_VEC_ELT (tempargs, i) = NULL_TREE; else if (oldelt && !template_args_equal (oldelt, elt)) return 0; } for (i = nargs; i--; ) { tree elt = TREE_VEC_ELT (tempargs, i); if (elt) TREE_VEC_ELT (targs, i) = elt; } return 1; } /* PARM is a template class (perhaps with unbound template parameters). ARG is a fully instantiated type. If ARG can be bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and TARGS are as for unify. */ static tree try_class_unification (tree tparms, tree targs, tree parm, tree arg) { tree copy_of_targs; if (!CLASSTYPE_TEMPLATE_INFO (arg) || (most_general_template (CLASSTYPE_TI_TEMPLATE (arg)) != most_general_template (CLASSTYPE_TI_TEMPLATE (parm)))) return NULL_TREE; /* We need to make a new template argument vector for the call to unify. If we used TARGS, we'd clutter it up with the result of the attempted unification, even if this class didn't work out. We also don't want to commit ourselves to all the unifications we've already done, since unification is supposed to be done on an argument-by-argument basis. In other words, consider the following pathological case: template <int I, int J, int K> struct S {}; template <int I, int J> struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {}; template <int I, int J, int K> void f(S<I, J, K>, S<I, I, I>); void g() { S<0, 0, 0> s0; S<0, 1, 2> s2; f(s0, s2); } Now, by the time we consider the unification involving `s2', we already know that we must have `f<0, 0, 0>'. But, even though `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid because there are two ways to unify base classes of S<0, 1, 2> with S<I, I, I>. If we kept the already deduced knowledge, we would reject the possibility I=1. */ copy_of_targs = make_tree_vec (TREE_VEC_LENGTH (targs)); /* If unification failed, we're done. */ if (unify (tparms, copy_of_targs, CLASSTYPE_TI_ARGS (parm), CLASSTYPE_TI_ARGS (arg), UNIFY_ALLOW_NONE)) return NULL_TREE; return arg; } /* Given a template type PARM and a class type ARG, find the unique base type in ARG that is an instance of PARM. We do not examine ARG itself; only its base-classes. If there is not exactly one appropriate base class, return NULL_TREE. PARM may be the type of a partial specialization, as well as a plain template type. Used by unify. */ static tree get_template_base (tree tparms, tree targs, tree parm, tree arg) { tree rval = NULL_TREE; tree binfo; gcc_assert (RECORD_OR_UNION_CODE_P (TREE_CODE (arg))); binfo = TYPE_BINFO (complete_type (arg)); if (!binfo) /* The type could not be completed. */ return NULL_TREE; /* Walk in inheritance graph order. The search order is not important, and this avoids multiple walks of virtual bases. */ for (binfo = TREE_CHAIN (binfo); binfo; binfo = TREE_CHAIN (binfo)) { tree r = try_class_unification (tparms, targs, parm, BINFO_TYPE (binfo)); if (r) { /* If there is more than one satisfactory baseclass, then: [temp.deduct.call] If they yield more than one possible deduced A, the type deduction fails. applies. */ if (rval && !same_type_p (r, rval)) return NULL_TREE; rval = r; } } return rval; } /* Returns the level of DECL, which declares a template parameter. */ static int template_decl_level (tree decl) { switch (TREE_CODE (decl)) { case TYPE_DECL: case TEMPLATE_DECL: return TEMPLATE_TYPE_LEVEL (TREE_TYPE (decl)); case PARM_DECL: return TEMPLATE_PARM_LEVEL (DECL_INITIAL (decl)); default: gcc_unreachable (); } return 0; } /* Decide whether ARG can be unified with PARM, considering only the cv-qualifiers of each type, given STRICT as documented for unify. Returns nonzero iff the unification is OK on that basis. */ static int check_cv_quals_for_unify (int strict, tree arg, tree parm) { int arg_quals = cp_type_quals (arg); int parm_quals = cp_type_quals (parm); if (TREE_CODE (parm) == TEMPLATE_TYPE_PARM && !(strict & UNIFY_ALLOW_OUTER_MORE_CV_QUAL)) { /* Although a CVR qualifier is ignored when being applied to a substituted template parameter ([8.3.2]/1 for example), that does not apply during deduction [14.8.2.4]/1, (even though that is not explicitly mentioned, [14.8.2.4]/9 indicates this). Except when we're allowing additional CV qualifiers at the outer level [14.8.2.1]/3,1st bullet. */ if ((TREE_CODE (arg) == REFERENCE_TYPE || TREE_CODE (arg) == FUNCTION_TYPE || TREE_CODE (arg) == METHOD_TYPE) && (parm_quals & (TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE))) return 0; if ((!POINTER_TYPE_P (arg) && TREE_CODE (arg) != TEMPLATE_TYPE_PARM) && (parm_quals & TYPE_QUAL_RESTRICT)) return 0; } if (!(strict & (UNIFY_ALLOW_MORE_CV_QUAL | UNIFY_ALLOW_OUTER_MORE_CV_QUAL)) && (arg_quals & parm_quals) != parm_quals) return 0; if (!(strict & (UNIFY_ALLOW_LESS_CV_QUAL | UNIFY_ALLOW_OUTER_LESS_CV_QUAL)) && (parm_quals & arg_quals) != arg_quals) return 0; return 1; } /* Determines the LEVEL and INDEX for the template parameter PARM. */ void template_parm_level_and_index (tree parm, int* level, int* index) { if (TREE_CODE (parm) == TEMPLATE_TYPE_PARM || TREE_CODE (parm) == TEMPLATE_TEMPLATE_PARM || TREE_CODE (parm) == BOUND_TEMPLATE_TEMPLATE_PARM) { *index = TEMPLATE_TYPE_IDX (parm); *level = TEMPLATE_TYPE_LEVEL (parm); } else { *index = TEMPLATE_PARM_IDX (parm); *level = TEMPLATE_PARM_LEVEL (parm); } } /* Unifies the remaining arguments in PACKED_ARGS with the pack expansion at the end of PACKED_PARMS. Returns 0 if the type deduction succeeds, 1 otherwise. STRICT is the same as in unify. CALL_ARGS_P is true iff PACKED_ARGS is actually a function call argument list. We'll need to adjust the arguments to make them types. SUBR tells us if this is from a recursive call to type_unification_real. */ int unify_pack_expansion (tree tparms, tree targs, tree packed_parms, tree packed_args, int strict, bool call_args_p, bool subr) { tree parm = TREE_VEC_ELT (packed_parms, TREE_VEC_LENGTH (packed_parms) - 1); tree pattern = PACK_EXPANSION_PATTERN (parm); tree pack, packs = NULL_TREE; int i, start = TREE_VEC_LENGTH (packed_parms) - 1; int len = TREE_VEC_LENGTH (packed_args); /* Determine the parameter packs we will be deducing from the pattern, and record their current deductions. */ for (pack = PACK_EXPANSION_PARAMETER_PACKS (parm); pack; pack = TREE_CHAIN (pack)) { tree parm_pack = TREE_VALUE (pack); int idx, level; /* Determine the index and level of this parameter pack. */ template_parm_level_and_index (parm_pack, &level, &idx); /* Keep track of the parameter packs and their corresponding argument packs. */ packs = tree_cons (parm_pack, TMPL_ARG (targs, level, idx), packs); TREE_TYPE (packs) = make_tree_vec (len - start); } /* Loop through all of the arguments that have not yet been unified and unify each with the pattern. */ for (i = start; i < len; i++) { tree parm = pattern; /* For each parameter pack, clear out the deduced value so that we can deduce it again. */ for (pack = packs; pack; pack = TREE_CHAIN (pack)) { int idx, level; template_parm_level_and_index (TREE_PURPOSE (pack), &level, &idx); TMPL_ARG (targs, level, idx) = NULL_TREE; } /* Unify the pattern with the current argument. */ { tree arg = TREE_VEC_ELT (packed_args, i); tree arg_expr = NULL_TREE; int arg_strict = strict; bool skip_arg_p = false; if (call_args_p) { int sub_strict; /* This mirrors what we do in type_unification_real. */ switch (strict) { case DEDUCE_CALL: sub_strict = (UNIFY_ALLOW_OUTER_LEVEL | UNIFY_ALLOW_MORE_CV_QUAL | UNIFY_ALLOW_DERIVED); break; case DEDUCE_CONV: sub_strict = UNIFY_ALLOW_LESS_CV_QUAL; break; case DEDUCE_EXACT: sub_strict = UNIFY_ALLOW_NONE; break; default: gcc_unreachable (); } if (!TYPE_P (arg)) { gcc_assert (TREE_TYPE (arg) != NULL_TREE); if (type_unknown_p (arg)) { /* [temp.deduct.type] A template-argument can be deduced from a pointer to function or pointer to member function argument if the set of overloaded functions does not contain function templates and at most one of a set of overloaded functions provides a unique match. */ if (resolve_overloaded_unification (tparms, targs, parm, arg, (unification_kind_t) strict, sub_strict) != 0) return 1; skip_arg_p = true; } if (!skip_arg_p) { arg_expr = arg; arg = unlowered_expr_type (arg); if (arg == error_mark_node) return 1; } } arg_strict = sub_strict; if (!subr) arg_strict |= maybe_adjust_types_for_deduction ((unification_kind_t) strict, &parm, &arg, arg_expr); } if (!skip_arg_p) { /* For deduction from an init-list we need the actual list. */ if (arg_expr && BRACE_ENCLOSED_INITIALIZER_P (arg_expr)) arg = arg_expr; if (unify (tparms, targs, parm, arg, arg_strict)) return 1; } } /* For each parameter pack, collect the deduced value. */ for (pack = packs; pack; pack = TREE_CHAIN (pack)) { int idx, level; template_parm_level_and_index (TREE_PURPOSE (pack), &level, &idx); TREE_VEC_ELT (TREE_TYPE (pack), i - start) = TMPL_ARG (targs, level, idx); } } /* Verify that the results of unification with the parameter packs produce results consistent with what we've seen before, and make the deduced argument packs available. */ for (pack = packs; pack; pack = TREE_CHAIN (pack)) { tree old_pack = TREE_VALUE (pack); tree new_args = TREE_TYPE (pack); int i, len = TREE_VEC_LENGTH (new_args); int idx, level; bool nondeduced_p = false; /* By default keep the original deduced argument pack. If necessary, more specific code is going to update the resulting deduced argument later down in this function. */ template_parm_level_and_index (TREE_PURPOSE (pack), &level, &idx); TMPL_ARG (targs, level, idx) = old_pack; /* If NEW_ARGS contains any NULL_TREE entries, we didn't actually deduce anything. */ for (i = 0; i < len && !nondeduced_p; ++i) if (TREE_VEC_ELT (new_args, i) == NULL_TREE) nondeduced_p = true; if (nondeduced_p) continue; if (old_pack && ARGUMENT_PACK_INCOMPLETE_P (old_pack)) { /* Prepend the explicit arguments onto NEW_ARGS. */ tree explicit_args = ARGUMENT_PACK_EXPLICIT_ARGS (old_pack); tree old_args = new_args; int i, explicit_len = TREE_VEC_LENGTH (explicit_args); int len = explicit_len + TREE_VEC_LENGTH (old_args); /* Copy the explicit arguments. */ new_args = make_tree_vec (len); for (i = 0; i < explicit_len; i++) TREE_VEC_ELT (new_args, i) = TREE_VEC_ELT (explicit_args, i); /* Copy the deduced arguments. */ for (; i < len; i++) TREE_VEC_ELT (new_args, i) = TREE_VEC_ELT (old_args, i - explicit_len); } if (!old_pack) { tree result; /* Build the deduced *_ARGUMENT_PACK. */ if (TREE_CODE (TREE_PURPOSE (pack)) == TEMPLATE_PARM_INDEX) { result = make_node (NONTYPE_ARGUMENT_PACK); TREE_TYPE (result) = TREE_TYPE (TEMPLATE_PARM_DECL (TREE_PURPOSE (pack))); TREE_CONSTANT (result) = 1; } else result = cxx_make_type (TYPE_ARGUMENT_PACK); SET_ARGUMENT_PACK_ARGS (result, new_args); /* Note the deduced argument packs for this parameter pack. */ TMPL_ARG (targs, level, idx) = result; } else if (ARGUMENT_PACK_INCOMPLETE_P (old_pack) && (ARGUMENT_PACK_ARGS (old_pack) == ARGUMENT_PACK_EXPLICIT_ARGS (old_pack))) { /* We only had the explicitly-provided arguments before, but now we have a complete set of arguments. */ tree explicit_args = ARGUMENT_PACK_EXPLICIT_ARGS (old_pack); SET_ARGUMENT_PACK_ARGS (old_pack, new_args); ARGUMENT_PACK_INCOMPLETE_P (old_pack) = 1; ARGUMENT_PACK_EXPLICIT_ARGS (old_pack) = explicit_args; } else if (!comp_template_args (ARGUMENT_PACK_ARGS (old_pack), new_args)) /* Inconsistent unification of this parameter pack. */ return 1; } return 0; } /* Deduce the value of template parameters. TPARMS is the (innermost) set of template parameters to a template. TARGS is the bindings for those template parameters, as determined thus far; TARGS may include template arguments for outer levels of template parameters as well. PARM is a parameter to a template function, or a subcomponent of that parameter; ARG is the corresponding argument. This function attempts to match PARM with ARG in a manner consistent with the existing assignments in TARGS. If more values are deduced, then TARGS is updated. Returns 0 if the type deduction succeeds, 1 otherwise. The parameter STRICT is a bitwise or of the following flags: UNIFY_ALLOW_NONE: Require an exact match between PARM and ARG. UNIFY_ALLOW_MORE_CV_QUAL: Allow the deduced ARG to be more cv-qualified (by qualification conversion) than ARG. UNIFY_ALLOW_LESS_CV_QUAL: Allow the deduced ARG to be less cv-qualified than ARG. UNIFY_ALLOW_DERIVED: Allow the deduced ARG to be a template base class of ARG, or a pointer to a template base class of the type pointed to by ARG. UNIFY_ALLOW_INTEGER: Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX case for more information. UNIFY_ALLOW_OUTER_LEVEL: This is the outermost level of a deduction. Used to determine validity of qualification conversions. A valid qualification conversion must have const qualified pointers leading up to the inner type which requires additional CV quals, except at the outer level, where const is not required [conv.qual]. It would be normal to set this flag in addition to setting UNIFY_ALLOW_MORE_CV_QUAL. UNIFY_ALLOW_OUTER_MORE_CV_QUAL: This is the outermost level of a deduction, and PARM can be more CV qualified at this point. UNIFY_ALLOW_OUTER_LESS_CV_QUAL: This is the outermost level of a deduction, and PARM can be less CV qualified at this point. */ static int unify (tree tparms, tree targs, tree parm, tree arg, int strict) { int idx; tree targ; tree tparm; int strict_in = strict; /* I don't think this will do the right thing with respect to types. But the only case I've seen it in so far has been array bounds, where signedness is the only information lost, and I think that will be okay. */ while (TREE_CODE (parm) == NOP_EXPR) parm = TREE_OPERAND (parm, 0); if (arg == error_mark_node) return 1; if (arg == unknown_type_node || arg == init_list_type_node) /* We can't deduce anything from this, but we might get all the template args from other function args. */ return 0; /* If PARM uses template parameters, then we can't bail out here, even if ARG == PARM, since we won't record unifications for the template parameters. We might need them if we're trying to figure out which of two things is more specialized. */ if (arg == parm && !uses_template_parms (parm)) return 0; /* Handle init lists early, so the rest of the function can assume we're dealing with a type. */ if (BRACE_ENCLOSED_INITIALIZER_P (arg)) { tree elt, elttype; unsigned i; tree orig_parm = parm; /* Replace T with std::initializer_list<T> for deduction. */ if (TREE_CODE (parm) == TEMPLATE_TYPE_PARM && flag_deduce_init_list) parm = listify (parm); if (!is_std_init_list (parm)) /* We can only deduce from an initializer list argument if the parameter is std::initializer_list; otherwise this is a non-deduced context. */ return 0; elttype = TREE_VEC_ELT (CLASSTYPE_TI_ARGS (parm), 0); FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (arg), i, elt) { int elt_strict = strict; if (!BRACE_ENCLOSED_INITIALIZER_P (elt)) { tree type = TREE_TYPE (elt); /* It should only be possible to get here for a call. */ gcc_assert (elt_strict & UNIFY_ALLOW_OUTER_LEVEL); elt_strict |= maybe_adjust_types_for_deduction (DEDUCE_CALL, &elttype, &type, elt); elt = type; } if (unify (tparms, targs, elttype, elt, elt_strict)) return 1; } /* If the std::initializer_list<T> deduction worked, replace the deduced A with std::initializer_list<A>. */ if (orig_parm != parm) { idx = TEMPLATE_TYPE_IDX (orig_parm); targ = TREE_VEC_ELT (INNERMOST_TEMPLATE_ARGS (targs), idx); targ = listify (targ); TREE_VEC_ELT (INNERMOST_TEMPLATE_ARGS (targs), idx) = targ; } return 0; } /* Immediately reject some pairs that won't unify because of cv-qualification mismatches. */ if (TREE_CODE (arg) == TREE_CODE (parm) && TYPE_P (arg) /* It is the elements of the array which hold the cv quals of an array type, and the elements might be template type parms. We'll check when we recurse. */ && TREE_CODE (arg) != ARRAY_TYPE /* We check the cv-qualifiers when unifying with template type parameters below. We want to allow ARG `const T' to unify with PARM `T' for example, when computing which of two templates is more specialized, for example. */ && TREE_CODE (arg) != TEMPLATE_TYPE_PARM && !check_cv_quals_for_unify (strict_in, arg, parm)) return 1; if (!(strict & UNIFY_ALLOW_OUTER_LEVEL) && TYPE_P (parm) && !CP_TYPE_CONST_P (parm)) strict &= ~UNIFY_ALLOW_MORE_CV_QUAL; strict &= ~UNIFY_ALLOW_OUTER_LEVEL; strict &= ~UNIFY_ALLOW_DERIVED; strict &= ~UNIFY_ALLOW_OUTER_MORE_CV_QUAL; strict &= ~UNIFY_ALLOW_OUTER_LESS_CV_QUAL; switch (TREE_CODE (parm)) { case TYPENAME_TYPE: case SCOPE_REF: case UNBOUND_CLASS_TEMPLATE: /* In a type which contains a nested-name-specifier, template argument values cannot be deduced for template parameters used within the nested-name-specifier. */ return 0; case TEMPLATE_TYPE_PARM: case TEMPLATE_TEMPLATE_PARM: case BOUND_TEMPLATE_TEMPLATE_PARM: tparm = TREE_VALUE (TREE_VEC_ELT (tparms, 0)); if (tparm == error_mark_node) return 1; if (TEMPLATE_TYPE_LEVEL (parm) != template_decl_level (tparm)) /* The PARM is not one we're trying to unify. Just check to see if it matches ARG. */ return (TREE_CODE (arg) == TREE_CODE (parm) && same_type_p (parm, arg)) ? 0 : 1; idx = TEMPLATE_TYPE_IDX (parm); targ = TREE_VEC_ELT (INNERMOST_TEMPLATE_ARGS (targs), idx); tparm = TREE_VALUE (TREE_VEC_ELT (tparms, idx)); /* Check for mixed types and values. */ if ((TREE_CODE (parm) == TEMPLATE_TYPE_PARM && TREE_CODE (tparm) != TYPE_DECL) || (TREE_CODE (parm) == TEMPLATE_TEMPLATE_PARM && TREE_CODE (tparm) != TEMPLATE_DECL)) return 1; if (TREE_CODE (parm) == BOUND_TEMPLATE_TEMPLATE_PARM) { /* ARG must be constructed from a template class or a template template parameter. */ if (TREE_CODE (arg) != BOUND_TEMPLATE_TEMPLATE_PARM && !CLASSTYPE_SPECIALIZATION_OF_PRIMARY_TEMPLATE_P (arg)) return 1; { tree parmvec = TYPE_TI_ARGS (parm); tree argvec = INNERMOST_TEMPLATE_ARGS (TYPE_TI_ARGS (arg)); tree parm_parms = DECL_INNERMOST_TEMPLATE_PARMS (TEMPLATE_TEMPLATE_PARM_TEMPLATE_DECL (parm)); int i, len; int parm_variadic_p = 0; /* The resolution to DR150 makes clear that default arguments for an N-argument may not be used to bind T to a template template parameter with fewer than N parameters. It is not safe to permit the binding of default arguments as an extension, as that may change the meaning of a conforming program. Consider: struct Dense { static const unsigned int dim = 1; }; template <template <typename> class View, typename Block> void operator+(float, View<Block> const&); template <typename Block, unsigned int Dim = Block::dim> struct Lvalue_proxy { operator float() const; }; void test_1d (void) { Lvalue_proxy<Dense> p; float b; b + p; } Here, if Lvalue_proxy is permitted to bind to View, then the global operator+ will be used; if they are not, the Lvalue_proxy will be converted to float. */ if (coerce_template_parms (parm_parms, argvec, TYPE_TI_TEMPLATE (parm), tf_none, /*require_all_args=*/true, /*use_default_args=*/false) == error_mark_node) return 1; /* Deduce arguments T, i from TT<T> or TT<i>. We check each element of PARMVEC and ARGVEC individually rather than the whole TREE_VEC since they can have different number of elements. */ parmvec = expand_template_argument_pack (parmvec); argvec = expand_template_argument_pack (argvec); len = TREE_VEC_LENGTH (parmvec); /* Check if the parameters end in a pack, making them variadic. */ if (len > 0 && PACK_EXPANSION_P (TREE_VEC_ELT (parmvec, len - 1))) parm_variadic_p = 1; if (TREE_VEC_LENGTH (argvec) < len - parm_variadic_p) return 1; for (i = 0; i < len - parm_variadic_p; ++i) { if (unify (tparms, targs, TREE_VEC_ELT (parmvec, i), TREE_VEC_ELT (argvec, i), UNIFY_ALLOW_NONE)) return 1; } if (parm_variadic_p && unify_pack_expansion (tparms, targs, parmvec, argvec, UNIFY_ALLOW_NONE, /*call_args_p=*/false, /*subr=*/false)) return 1; } arg = TYPE_TI_TEMPLATE (arg); /* Fall through to deduce template name. */ } if (TREE_CODE (parm) == TEMPLATE_TEMPLATE_PARM || TREE_CODE (parm) == BOUND_TEMPLATE_TEMPLATE_PARM) { /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */ /* Simple cases: Value already set, does match or doesn't. */ if (targ != NULL_TREE && template_args_equal (targ, arg)) return 0; else if (targ) return 1; } else { /* If PARM is `const T' and ARG is only `int', we don't have a match unless we are allowing additional qualification. If ARG is `const int' and PARM is just `T' that's OK; that binds `const int' to `T'. */ if (!check_cv_quals_for_unify (strict_in | UNIFY_ALLOW_LESS_CV_QUAL, arg, parm)) return 1; /* Consider the case where ARG is `const volatile int' and PARM is `const T'. Then, T should be `volatile int'. */ arg = cp_build_qualified_type_real (arg, cp_type_quals (arg) & ~cp_type_quals (parm), tf_none); if (arg == error_mark_node) return 1; /* Simple cases: Value already set, does match or doesn't. */ if (targ != NULL_TREE && same_type_p (targ, arg)) return 0; else if (targ) return 1; /* Make sure that ARG is not a variable-sized array. (Note that were talking about variable-sized arrays (like `int[n]'), rather than arrays of unknown size (like `int[]').) We'll get very confused by such a type since the bound of the array will not be computable in an instantiation. Besides, such types are not allowed in ISO C++, so we can do as we please here. */ if (variably_modified_type_p (arg, NULL_TREE)) return 1; /* Strip typedefs as in convert_template_argument. */ arg = strip_typedefs (arg); } /* If ARG is a parameter pack or an expansion, we cannot unify against it unless PARM is also a parameter pack. */ if ((template_parameter_pack_p (arg) || PACK_EXPANSION_P (arg)) && !template_parameter_pack_p (parm)) return 1; /* If the argument deduction results is a METHOD_TYPE, then there is a problem. METHOD_TYPE doesn't map to any real C++ type the result of the deduction can not be of that type. */ if (TREE_CODE (arg) == METHOD_TYPE) return 1; TREE_VEC_ELT (INNERMOST_TEMPLATE_ARGS (targs), idx) = arg; return 0; case TEMPLATE_PARM_INDEX: tparm = TREE_VALUE (TREE_VEC_ELT (tparms, 0)); if (tparm == error_mark_node) return 1; if (TEMPLATE_PARM_LEVEL (parm) != template_decl_level (tparm)) /* The PARM is not one we're trying to unify. Just check to see if it matches ARG. */ return !(TREE_CODE (arg) == TREE_CODE (parm) && cp_tree_equal (parm, arg)); idx = TEMPLATE_PARM_IDX (parm); targ = TREE_VEC_ELT (INNERMOST_TEMPLATE_ARGS (targs), idx); if (targ) return !cp_tree_equal (targ, arg); /* [temp.deduct.type] If, in the declaration of a function template with a non-type template-parameter, the non-type template-parameter is used in an expression in the function parameter-list and, if the corresponding template-argument is deduced, the template-argument type shall match the type of the template-parameter exactly, except that a template-argument deduced from an array bound may be of any integral type. The non-type parameter might use already deduced type parameters. */ tparm = tsubst (TREE_TYPE (parm), targs, 0, NULL_TREE); if (!TREE_TYPE (arg)) /* Template-parameter dependent expression. Just accept it for now. It will later be processed in convert_template_argument. */ ; else if (same_type_p (TREE_TYPE (arg), tparm)) /* OK */; else if ((strict & UNIFY_ALLOW_INTEGER) && (TREE_CODE (tparm) == INTEGER_TYPE || TREE_CODE (tparm) == BOOLEAN_TYPE)) /* Convert the ARG to the type of PARM; the deduced non-type template argument must exactly match the types of the corresponding parameter. */ arg = fold (build_nop (tparm, arg)); else if (uses_template_parms (tparm)) /* We haven't deduced the type of this parameter yet. Try again later. */ return 0; else return 1; /* If ARG is a parameter pack or an expansion, we cannot unify against it unless PARM is also a parameter pack. */ if ((template_parameter_pack_p (arg) || PACK_EXPANSION_P (arg)) && !TEMPLATE_PARM_PARAMETER_PACK (parm)) return 1; TREE_VEC_ELT (INNERMOST_TEMPLATE_ARGS (targs), idx) = arg; return 0; case PTRMEM_CST: { /* A pointer-to-member constant can be unified only with another constant. */ if (TREE_CODE (arg) != PTRMEM_CST) return 1; /* Just unify the class member. It would be useless (and possibly wrong, depending on the strict flags) to unify also PTRMEM_CST_CLASS, because we want to be sure that both parm and arg refer to the same variable, even if through different classes. For instance: struct A { int x; }; struct B : A { }; Unification of &A::x and &B::x must succeed. */ return unify (tparms, targs, PTRMEM_CST_MEMBER (parm), PTRMEM_CST_MEMBER (arg), strict); } case POINTER_TYPE: { if (TREE_CODE (arg) != POINTER_TYPE) return 1; /* [temp.deduct.call] A can be another pointer or pointer to member type that can be converted to the deduced A via a qualification conversion (_conv.qual_). We pass down STRICT here rather than UNIFY_ALLOW_NONE. This will allow for additional cv-qualification of the pointed-to types if appropriate. */ if (TREE_CODE (TREE_TYPE (arg)) == RECORD_TYPE) /* The derived-to-base conversion only persists through one level of pointers. */ strict |= (strict_in & UNIFY_ALLOW_DERIVED); return unify (tparms, targs, TREE_TYPE (parm), TREE_TYPE (arg), strict); } case REFERENCE_TYPE: if (TREE_CODE (arg) != REFERENCE_TYPE) return 1; return unify (tparms, targs, TREE_TYPE (parm), TREE_TYPE (arg), strict & UNIFY_ALLOW_MORE_CV_QUAL); case ARRAY_TYPE: if (TREE_CODE (arg) != ARRAY_TYPE) return 1; if ((TYPE_DOMAIN (parm) == NULL_TREE) != (TYPE_DOMAIN (arg) == NULL_TREE)) return 1; if (TYPE_DOMAIN (parm) != NULL_TREE) { tree parm_max; tree arg_max; bool parm_cst; bool arg_cst; /* Our representation of array types uses "N - 1" as the TYPE_MAX_VALUE for an array with "N" elements, if "N" is not an integer constant. We cannot unify arbitrarily complex expressions, so we eliminate the MINUS_EXPRs here. */ parm_max = TYPE_MAX_VALUE (TYPE_DOMAIN (parm)); parm_cst = TREE_CODE (parm_max) == INTEGER_CST; if (!parm_cst) { gcc_assert (TREE_CODE (parm_max) == MINUS_EXPR); parm_max = TREE_OPERAND (parm_max, 0); } arg_max = TYPE_MAX_VALUE (TYPE_DOMAIN (arg)); arg_cst = TREE_CODE (arg_max) == INTEGER_CST; if (!arg_cst) { /* The ARG_MAX may not be a simple MINUS_EXPR, if we are trying to unify the type of a variable with the type of a template parameter. For example: template <unsigned int N> void f (char (&) [N]); int g(); void h(int i) { char a[g(i)]; f(a); } Here, the type of the ARG will be "int [g(i)]", and may be a SAVE_EXPR, etc. */ if (TREE_CODE (arg_max) != MINUS_EXPR) return 1; arg_max = TREE_OPERAND (arg_max, 0); } /* If only one of the bounds used a MINUS_EXPR, compensate by adding one to the other bound. */ if (parm_cst && !arg_cst) parm_max = fold_build2_loc (input_location, PLUS_EXPR, integer_type_node, parm_max, integer_one_node); else if (arg_cst && !parm_cst) arg_max = fold_build2_loc (input_location, PLUS_EXPR, integer_type_node, arg_max, integer_one_node); if (unify (tparms, targs, parm_max, arg_max, UNIFY_ALLOW_INTEGER)) return 1; } return unify (tparms, targs, TREE_TYPE (parm), TREE_TYPE (arg), strict & UNIFY_ALLOW_MORE_CV_QUAL); case REAL_TYPE: case COMPLEX_TYPE: case VECTOR_TYPE: case INTEGER_TYPE: case BOOLEAN_TYPE: case ENUMERAL_TYPE: case VOID_TYPE: if (TREE_CODE (arg) != TREE_CODE (parm)) return 1; /* We have already checked cv-qualification at the top of the function. */ if (!same_type_ignoring_top_level_qualifiers_p (arg, parm)) return 1; /* As far as unification is concerned, this wins. Later checks will invalidate it if necessary. */ return 0; /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */ /* Type INTEGER_CST can come from ordinary constant template args. */ case INTEGER_CST: while (TREE_CODE (arg) == NOP_EXPR) arg = TREE_OPERAND (arg, 0); if (TREE_CODE (arg) != INTEGER_CST) return 1; return !tree_int_cst_equal (parm, arg); case TREE_VEC: { int i; if (TREE_CODE (arg) != TREE_VEC) return 1; if (TREE_VEC_LENGTH (parm) != TREE_VEC_LENGTH (arg)) return 1; for (i = 0; i < TREE_VEC_LENGTH (parm); ++i) if (unify (tparms, targs, TREE_VEC_ELT (parm, i), TREE_VEC_ELT (arg, i), UNIFY_ALLOW_NONE)) return 1; return 0; } case RECORD_TYPE: case UNION_TYPE: if (TREE_CODE (arg) != TREE_CODE (parm)) return 1; if (TYPE_PTRMEMFUNC_P (parm)) { if (!TYPE_PTRMEMFUNC_P (arg)) return 1; return unify (tparms, targs, TYPE_PTRMEMFUNC_FN_TYPE (parm), TYPE_PTRMEMFUNC_FN_TYPE (arg), strict); } if (CLASSTYPE_TEMPLATE_INFO (parm)) { tree t = NULL_TREE; if (strict_in & UNIFY_ALLOW_DERIVED) { /* First, we try to unify the PARM and ARG directly. */ t = try_class_unification (tparms, targs, parm, arg); if (!t) { /* Fallback to the special case allowed in [temp.deduct.call]: If P is a class, and P has the form template-id, then A can be a derived class of the deduced A. Likewise, if P is a pointer to a class of the form template-id, A can be a pointer to a derived class pointed to by the deduced A. */ t = get_template_base (tparms, targs, parm, arg); if (!t) return 1; } } else if (CLASSTYPE_TEMPLATE_INFO (arg) && (CLASSTYPE_TI_TEMPLATE (parm) == CLASSTYPE_TI_TEMPLATE (arg))) /* Perhaps PARM is something like S<U> and ARG is S<int>. Then, we should unify `int' and `U'. */ t = arg; else /* There's no chance of unification succeeding. */ return 1; return unify (tparms, targs, CLASSTYPE_TI_ARGS (parm), CLASSTYPE_TI_ARGS (t), UNIFY_ALLOW_NONE); } else if (!same_type_ignoring_top_level_qualifiers_p (parm, arg)) return 1; return 0; case METHOD_TYPE: case FUNCTION_TYPE: { unsigned int nargs; tree *args; tree a; unsigned int i; if (TREE_CODE (arg) != TREE_CODE (parm)) return 1; /* CV qualifications for methods can never be deduced, they must match exactly. We need to check them explicitly here, because type_unification_real treats them as any other cv-qualified parameter. */ if (TREE_CODE (parm) == METHOD_TYPE && (!check_cv_quals_for_unify (UNIFY_ALLOW_NONE, TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (arg))), TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (parm)))))) return 1; if (unify (tparms, targs, TREE_TYPE (parm), TREE_TYPE (arg), UNIFY_ALLOW_NONE)) return 1; nargs = list_length (TYPE_ARG_TYPES (arg)); args = XALLOCAVEC (tree, nargs); for (a = TYPE_ARG_TYPES (arg), i = 0; a != NULL_TREE && a != void_list_node; a = TREE_CHAIN (a), ++i) args[i] = TREE_VALUE (a); nargs = i; return type_unification_real (tparms, targs, TYPE_ARG_TYPES (parm), args, nargs, 1, DEDUCE_EXACT, LOOKUP_NORMAL); } case OFFSET_TYPE: /* Unify a pointer to member with a pointer to member function, which deduces the type of the member as a function type. */ if (TYPE_PTRMEMFUNC_P (arg)) { tree method_type; tree fntype; cp_cv_quals cv_quals; /* Check top-level cv qualifiers */ if (!check_cv_quals_for_unify (UNIFY_ALLOW_NONE, arg, parm)) return 1; if (unify (tparms, targs, TYPE_OFFSET_BASETYPE (parm), TYPE_PTRMEMFUNC_OBJECT_TYPE (arg), UNIFY_ALLOW_NONE)) return 1; /* Determine the type of the function we are unifying against. */ method_type = TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (arg)); fntype = build_function_type (TREE_TYPE (method_type), TREE_CHAIN (TYPE_ARG_TYPES (method_type))); /* Extract the cv-qualifiers of the member function from the implicit object parameter and place them on the function type to be restored later. */ cv_quals = cp_type_quals(TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (method_type)))); fntype = build_qualified_type (fntype, cv_quals); return unify (tparms, targs, TREE_TYPE (parm), fntype, strict); } if (TREE_CODE (arg) != OFFSET_TYPE) return 1; if (unify (tparms, targs, TYPE_OFFSET_BASETYPE (parm), TYPE_OFFSET_BASETYPE (arg), UNIFY_ALLOW_NONE)) return 1; return unify (tparms, targs, TREE_TYPE (parm), TREE_TYPE (arg), strict); case CONST_DECL: if (DECL_TEMPLATE_PARM_P (parm)) return unify (tparms, targs, DECL_INITIAL (parm), arg, strict); if (arg != integral_constant_value (parm)) return 1; return 0; case FIELD_DECL: case TEMPLATE_DECL: /* Matched cases are handled by the ARG == PARM test above. */ return 1; case VAR_DECL: /* A non-type template parameter that is a variable should be a an integral constant, in which case, it whould have been folded into its (constant) value. So we should not be getting a variable here. */ gcc_unreachable (); case TYPE_ARGUMENT_PACK: case NONTYPE_ARGUMENT_PACK: { tree packed_parms = ARGUMENT_PACK_ARGS (parm); tree packed_args = ARGUMENT_PACK_ARGS (arg); int i, len = TREE_VEC_LENGTH (packed_parms); int argslen = TREE_VEC_LENGTH (packed_args); int parm_variadic_p = 0; for (i = 0; i < len; ++i) { if (PACK_EXPANSION_P (TREE_VEC_ELT (packed_parms, i))) { if (i == len - 1) /* We can unify against something with a trailing parameter pack. */ parm_variadic_p = 1; else /* Since there is something following the pack expansion, we cannot unify this template argument list. */ return 0; } } /* If we don't have enough arguments to satisfy the parameters (not counting the pack expression at the end), or we have too many arguments for a parameter list that doesn't end in a pack expression, we can't unify. */ if (argslen < (len - parm_variadic_p) || (argslen > len && !parm_variadic_p)) return 1; /* Unify all of the parameters that precede the (optional) pack expression. */ for (i = 0; i < len - parm_variadic_p; ++i) { if (unify (tparms, targs, TREE_VEC_ELT (packed_parms, i), TREE_VEC_ELT (packed_args, i), strict)) return 1; } if (parm_variadic_p) return unify_pack_expansion (tparms, targs, packed_parms, packed_args, strict, /*call_args_p=*/false, /*subr=*/false); return 0; } break; case TYPEOF_TYPE: case DECLTYPE_TYPE: /* Cannot deduce anything from TYPEOF_TYPE or DECLTYPE_TYPE nodes. */ return 0; case ERROR_MARK: /* Unification fails if we hit an error node. */ return 1; default: gcc_assert (EXPR_P (parm)); /* We must be looking at an expression. This can happen with something like: template <int I> void foo(S<I>, S<I + 2>); This is a "nondeduced context": [deduct.type] The nondeduced contexts are: --A type that is a template-id in which one or more of the template-arguments is an expression that references a template-parameter. In these cases, we assume deduction succeeded, but don't actually infer any unifications. */ if (!uses_template_parms (parm) && !template_args_equal (parm, arg)) return 1; else return 0; } } /* Note that DECL can be defined in this translation unit, if required. */ static void mark_definable (tree decl) { tree clone; DECL_NOT_REALLY_EXTERN (decl) = 1; FOR_EACH_CLONE (clone, decl) DECL_NOT_REALLY_EXTERN (clone) = 1; } /* Called if RESULT is explicitly instantiated, or is a member of an explicitly instantiated class. */ void mark_decl_instantiated (tree result, int extern_p) { SET_DECL_EXPLICIT_INSTANTIATION (result); /* If this entity has already been written out, it's too late to make any modifications. */ if (TREE_ASM_WRITTEN (result)) return; if (TREE_CODE (result) != FUNCTION_DECL) /* The TREE_PUBLIC flag for function declarations will have been set correctly by tsubst. */ TREE_PUBLIC (result) = 1; /* This might have been set by an earlier implicit instantiation. */ DECL_COMDAT (result) = 0; if (extern_p) DECL_NOT_REALLY_EXTERN (result) = 0; else { mark_definable (result); /* Always make artificials weak. */ if (DECL_ARTIFICIAL (result) && flag_weak) comdat_linkage (result); /* For WIN32 we also want to put explicit instantiations in linkonce sections. */ else if (TREE_PUBLIC (result)) maybe_make_one_only (result); } /* If EXTERN_P, then this function will not be emitted -- unless followed by an explicit instantiation, at which point its linkage will be adjusted. If !EXTERN_P, then this function will be emitted here. In neither circumstance do we want import_export_decl to adjust the linkage. */ DECL_INTERFACE_KNOWN (result) = 1; } /* Subroutine of more_specialized_fn: check whether TARGS is missing any important template arguments. If any are missing, we check whether they're important by using error_mark_node for substituting into any args that were used for partial ordering (the ones between ARGS and END) and seeing if it bubbles up. */ static bool check_undeduced_parms (tree targs, tree args, tree end) { bool found = false; int i; for (i = TREE_VEC_LENGTH (targs) - 1; i >= 0; --i) if (TREE_VEC_ELT (targs, i) == NULL_TREE) { found = true; TREE_VEC_ELT (targs, i) = error_mark_node; } if (found) { for (; args != end; args = TREE_CHAIN (args)) { tree substed = tsubst (TREE_VALUE (args), targs, tf_none, NULL_TREE); if (substed == error_mark_node) return true; } } return false; } /* Given two function templates PAT1 and PAT2, return: 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order]. -1 if PAT2 is more specialized than PAT1. 0 if neither is more specialized. LEN indicates the number of parameters we should consider (defaulted parameters should not be considered). The 1998 std underspecified function template partial ordering, and DR214 addresses the issue. We take pairs of arguments, one from each of the templates, and deduce them against each other. One of the templates will be more specialized if all the *other* template's arguments deduce against its arguments and at least one of its arguments *does* *not* deduce against the other template's corresponding argument. Deduction is done as for class templates. The arguments used in deduction have reference and top level cv qualifiers removed. Iff both arguments were originally reference types *and* deduction succeeds in both directions, the template with the more cv-qualified argument wins for that pairing (if neither is more cv-qualified, they both are equal). Unlike regular deduction, after all the arguments have been deduced in this way, we do *not* verify the deduced template argument values can be substituted into non-deduced contexts. The logic can be a bit confusing here, because we look at deduce1 and targs1 to see if pat2 is at least as specialized, and vice versa; if we can find template arguments for pat1 to make arg1 look like arg2, that means that arg2 is at least as specialized as arg1. */ int more_specialized_fn (tree pat1, tree pat2, int len) { tree decl1 = DECL_TEMPLATE_RESULT (pat1); tree decl2 = DECL_TEMPLATE_RESULT (pat2); tree targs1 = make_tree_vec (DECL_NTPARMS (pat1)); tree targs2 = make_tree_vec (DECL_NTPARMS (pat2)); tree tparms1 = DECL_INNERMOST_TEMPLATE_PARMS (pat1); tree tparms2 = DECL_INNERMOST_TEMPLATE_PARMS (pat2); tree args1 = TYPE_ARG_TYPES (TREE_TYPE (decl1)); tree args2 = TYPE_ARG_TYPES (TREE_TYPE (decl2)); tree origs1, origs2; bool lose1 = false; bool lose2 = false; /* Remove the this parameter from non-static member functions. If one is a non-static member function and the other is not a static member function, remove the first parameter from that function also. This situation occurs for operator functions where we locate both a member function (with this pointer) and non-member operator (with explicit first operand). */ if (DECL_NONSTATIC_MEMBER_FUNCTION_P (decl1)) { len--; /* LEN is the number of significant arguments for DECL1 */ args1 = TREE_CHAIN (args1); if (!DECL_STATIC_FUNCTION_P (decl2)) args2 = TREE_CHAIN (args2); } else if (DECL_NONSTATIC_MEMBER_FUNCTION_P (decl2)) { args2 = TREE_CHAIN (args2); if (!DECL_STATIC_FUNCTION_P (decl1)) { len--; args1 = TREE_CHAIN (args1); } } /* If only one is a conversion operator, they are unordered. */ if (DECL_CONV_FN_P (decl1) != DECL_CONV_FN_P (decl2)) return 0; /* Consider the return type for a conversion function */ if (DECL_CONV_FN_P (decl1)) { args1 = tree_cons (NULL_TREE, TREE_TYPE (TREE_TYPE (decl1)), args1); args2 = tree_cons (NULL_TREE, TREE_TYPE (TREE_TYPE (decl2)), args2); len++; } processing_template_decl++; origs1 = args1; origs2 = args2; while (len-- /* Stop when an ellipsis is seen. */ && args1 != NULL_TREE && args2 != NULL_TREE) { tree arg1 = TREE_VALUE (args1); tree arg2 = TREE_VALUE (args2); int deduce1, deduce2; int quals1 = -1; int quals2 = -1; if (TREE_CODE (arg1) == TYPE_PACK_EXPANSION && TREE_CODE (arg2) == TYPE_PACK_EXPANSION) { /* When both arguments are pack expansions, we need only unify the patterns themselves. */ arg1 = PACK_EXPANSION_PATTERN (arg1); arg2 = PACK_EXPANSION_PATTERN (arg2); /* This is the last comparison we need to do. */ len = 0; } if (TREE_CODE (arg1) == REFERENCE_TYPE) { arg1 = TREE_TYPE (arg1); quals1 = cp_type_quals (arg1); } if (TREE_CODE (arg2) == REFERENCE_TYPE) { arg2 = TREE_TYPE (arg2); quals2 = cp_type_quals (arg2); } if ((quals1 < 0) != (quals2 < 0)) { /* Only of the args is a reference, see if we should apply array/function pointer decay to it. This is not part of DR214, but is, IMHO, consistent with the deduction rules for the function call itself, and with our earlier implementation of the underspecified partial ordering rules. (nathan). */ if (quals1 >= 0) { switch (TREE_CODE (arg1)) { case ARRAY_TYPE: arg1 = TREE_TYPE (arg1); /* FALLTHROUGH. */ case FUNCTION_TYPE: arg1 = build_pointer_type (arg1); break; default: break; } } else { switch (TREE_CODE (arg2)) { case ARRAY_TYPE: arg2 = TREE_TYPE (arg2); /* FALLTHROUGH. */ case FUNCTION_TYPE: arg2 = build_pointer_type (arg2); break; default: break; } } } arg1 = TYPE_MAIN_VARIANT (arg1); arg2 = TYPE_MAIN_VARIANT (arg2); if (TREE_CODE (arg1) == TYPE_PACK_EXPANSION) { int i, len2 = list_length (args2); tree parmvec = make_tree_vec (1); tree argvec = make_tree_vec (len2); tree ta = args2; /* Setup the parameter vector, which contains only ARG1. */ TREE_VEC_ELT (parmvec, 0) = arg1; /* Setup the argument vector, which contains the remaining arguments. */ for (i = 0; i < len2; i++, ta = TREE_CHAIN (ta)) TREE_VEC_ELT (argvec, i) = TREE_VALUE (ta); deduce1 = !unify_pack_expansion (tparms1, targs1, parmvec, argvec, UNIFY_ALLOW_NONE, /*call_args_p=*/false, /*subr=*/0); /* We cannot deduce in the other direction, because ARG1 is a pack expansion but ARG2 is not. */ deduce2 = 0; } else if (TREE_CODE (arg2) == TYPE_PACK_EXPANSION) { int i, len1 = list_length (args1); tree parmvec = make_tree_vec (1); tree argvec = make_tree_vec (len1); tree ta = args1; /* Setup the parameter vector, which contains only ARG1. */ TREE_VEC_ELT (parmvec, 0) = arg2; /* Setup the argument vector, which contains the remaining arguments. */ for (i = 0; i < len1; i++, ta = TREE_CHAIN (ta)) TREE_VEC_ELT (argvec, i) = TREE_VALUE (ta); deduce2 = !unify_pack_expansion (tparms2, targs2, parmvec, argvec, UNIFY_ALLOW_NONE, /*call_args_p=*/false, /*subr=*/0); /* We cannot deduce in the other direction, because ARG2 is a pack expansion but ARG1 is not.*/ deduce1 = 0; } else { /* The normal case, where neither argument is a pack expansion. */ deduce1 = !unify (tparms1, targs1, arg1, arg2, UNIFY_ALLOW_NONE); deduce2 = !unify (tparms2, targs2, arg2, arg1, UNIFY_ALLOW_NONE); } /* If we couldn't deduce arguments for tparms1 to make arg1 match arg2, then arg2 is not as specialized as arg1. */ if (!deduce1) lose2 = true; if (!deduce2) lose1 = true; /* "If, for a given type, deduction succeeds in both directions (i.e., the types are identical after the transformations above) and if the type from the argument template is more cv-qualified than the type from the parameter template (as described above) that type is considered to be more specialized than the other. If neither type is more cv-qualified than the other then neither type is more specialized than the other." */ if (deduce1 && deduce2 && quals1 != quals2 && quals1 >= 0 && quals2 >= 0) { if ((quals1 & quals2) == quals2) lose2 = true; if ((quals1 & quals2) == quals1) lose1 = true; } if (lose1 && lose2) /* We've failed to deduce something in either direction. These must be unordered. */ break; if (TREE_CODE (arg1) == TYPE_PACK_EXPANSION || TREE_CODE (arg2) == TYPE_PACK_EXPANSION) /* We have already processed all of the arguments in our handing of the pack expansion type. */ len = 0; args1 = TREE_CHAIN (args1); args2 = TREE_CHAIN (args2); } /* "In most cases, all template parameters must have values in order for deduction to succeed, but for partial ordering purposes a template parameter may remain without a value provided it is not used in the types being used for partial ordering." Thus, if we are missing any of the targs1 we need to substitute into origs1, then pat2 is not as specialized as pat1. This can happen when there is a nondeduced context. */ if (!lose2 && check_undeduced_parms (targs1, origs1, args1)) lose2 = true; if (!lose1 && check_undeduced_parms (targs2, origs2, args2)) lose1 = true; processing_template_decl--; /* All things being equal, if the next argument is a pack expansion for one function but not for the other, prefer the non-variadic function. FIXME this is bogus; see c++/41958. */ if (lose1 == lose2 && args1 && TREE_VALUE (args1) && args2 && TREE_VALUE (args2)) { lose1 = TREE_CODE (TREE_VALUE (args1)) == TYPE_PACK_EXPANSION; lose2 = TREE_CODE (TREE_VALUE (args2)) == TYPE_PACK_EXPANSION; } if (lose1 == lose2) return 0; else if (!lose1) return 1; else return -1; } /* Determine which of two partial specializations is more specialized. PAT1 is a TREE_LIST whose TREE_TYPE is the _TYPE node corresponding to the first partial specialization. The TREE_VALUE is the innermost set of template parameters for the partial specialization. PAT2 is similar, but for the second template. Return 1 if the first partial specialization is more specialized; -1 if the second is more specialized; 0 if neither is more specialized. See [temp.class.order] for information about determining which of two templates is more specialized. */ static int more_specialized_class (tree pat1, tree pat2) { tree targs; tree tmpl1, tmpl2; int winner = 0; bool any_deductions = false; tmpl1 = TREE_TYPE (pat1); tmpl2 = TREE_TYPE (pat2); /* Just like what happens for functions, if we are ordering between different class template specializations, we may encounter dependent types in the arguments, and we need our dependency check functions to behave correctly. */ ++processing_template_decl; targs = get_class_bindings (TREE_VALUE (pat1), CLASSTYPE_TI_ARGS (tmpl1), CLASSTYPE_TI_ARGS (tmpl2)); if (targs) { --winner; any_deductions = true; } targs = get_class_bindings (TREE_VALUE (pat2), CLASSTYPE_TI_ARGS (tmpl2), CLASSTYPE_TI_ARGS (tmpl1)); if (targs) { ++winner; any_deductions = true; } --processing_template_decl; /* In the case of a tie where at least one of the class templates has a parameter pack at the end, the template with the most non-packed parameters wins. */ if (winner == 0 && any_deductions && (template_args_variadic_p (TREE_PURPOSE (pat1)) || template_args_variadic_p (TREE_PURPOSE (pat2)))) { tree args1 = INNERMOST_TEMPLATE_ARGS (TREE_PURPOSE (pat1)); tree args2 = INNERMOST_TEMPLATE_ARGS (TREE_PURPOSE (pat2)); int len1 = TREE_VEC_LENGTH (args1); int len2 = TREE_VEC_LENGTH (args2); /* We don't count the pack expansion at the end. */ if (template_args_variadic_p (TREE_PURPOSE (pat1))) --len1; if (template_args_variadic_p (TREE_PURPOSE (pat2))) --len2; if (len1 > len2) return 1; else if (len1 < len2) return -1; } return winner; } /* Return the template arguments that will produce the function signature DECL from the function template FN, with the explicit template arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must also match. Return NULL_TREE if no satisfactory arguments could be found. */ static tree get_bindings (tree fn, tree decl, tree explicit_args, bool check_rettype) { int ntparms = DECL_NTPARMS (fn); tree targs = make_tree_vec (ntparms); tree decl_type; tree decl_arg_types; tree *args; unsigned int nargs, ix; tree arg; /* Substitute the explicit template arguments into the type of DECL. The call to fn_type_unification will handle substitution into the FN. */ decl_type = TREE_TYPE (decl); if (explicit_args && uses_template_parms (decl_type)) { tree tmpl; tree converted_args; if (DECL_TEMPLATE_INFO (decl)) tmpl = DECL_TI_TEMPLATE (decl); else /* We can get here for some invalid specializations. */ return NULL_TREE; converted_args = coerce_template_parms (DECL_INNERMOST_TEMPLATE_PARMS (tmpl), explicit_args, NULL_TREE, tf_none, /*require_all_args=*/false, /*use_default_args=*/false); if (converted_args == error_mark_node) return NULL_TREE; decl_type = tsubst (decl_type, converted_args, tf_none, NULL_TREE); if (decl_type == error_mark_node) return NULL_TREE; } /* Never do unification on the 'this' parameter. */ decl_arg_types = skip_artificial_parms_for (decl, TYPE_ARG_TYPES (decl_type)); nargs = list_length (decl_arg_types); args = XALLOCAVEC (tree, nargs); for (arg = decl_arg_types, ix = 0; arg != NULL_TREE && arg != void_list_node; arg = TREE_CHAIN (arg), ++ix) args[ix] = TREE_VALUE (arg); if (fn_type_unification (fn, explicit_args, targs, args, ix, (check_rettype || DECL_CONV_FN_P (fn) ? TREE_TYPE (decl_type) : NULL_TREE), DEDUCE_EXACT, LOOKUP_NORMAL)) return NULL_TREE; return targs; } /* Return the innermost template arguments that, when applied to a template specialization whose innermost template parameters are TPARMS, and whose specialization arguments are SPEC_ARGS, yield the ARGS. For example, suppose we have: template <class T, class U> struct S {}; template <class T> struct S<T*, int> {}; Then, suppose we want to get `S<double*, int>'. The TPARMS will be {T}, the SPEC_ARGS will be {T*, int} and the ARGS will be {double*, int}. The resulting vector will be {double}, indicating that `T' is bound to `double'. */ static tree get_class_bindings (tree tparms, tree spec_args, tree args) { int i, ntparms = TREE_VEC_LENGTH (tparms); tree deduced_args; tree innermost_deduced_args; innermost_deduced_args = make_tree_vec (ntparms); if (TMPL_ARGS_HAVE_MULTIPLE_LEVELS (args)) { deduced_args = copy_node (args); SET_TMPL_ARGS_LEVEL (deduced_args, TMPL_ARGS_DEPTH (deduced_args), innermost_deduced_args); } else deduced_args = innermost_deduced_args; if (unify (tparms, deduced_args, INNERMOST_TEMPLATE_ARGS (spec_args), INNERMOST_TEMPLATE_ARGS (args), UNIFY_ALLOW_NONE)) return NULL_TREE; for (i = 0; i < ntparms; ++i) if (! TREE_VEC_ELT (innermost_deduced_args, i)) return NULL_TREE; /* Verify that nondeduced template arguments agree with the type obtained from argument deduction. For example: struct A { typedef int X; }; template <class T, class U> struct C {}; template <class T> struct C<T, typename T::X> {}; Then with the instantiation `C<A, int>', we can deduce that `T' is `A' but unify () does not check whether `typename T::X' is `int'. */ spec_args = tsubst (spec_args, deduced_args, tf_none, NULL_TREE); if (spec_args == error_mark_node /* We only need to check the innermost arguments; the other arguments will always agree. */ || !comp_template_args (INNERMOST_TEMPLATE_ARGS (spec_args), INNERMOST_TEMPLATE_ARGS (args))) return NULL_TREE; /* Now that we have bindings for all of the template arguments, ensure that the arguments deduced for the template template parameters have compatible template parameter lists. See the use of template_template_parm_bindings_ok_p in fn_type_unification for more information. */ if (!template_template_parm_bindings_ok_p (tparms, deduced_args)) return NULL_TREE; return deduced_args; } /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL. Return the TREE_LIST node with the most specialized template, if any. If there is no most specialized template, the error_mark_node is returned. Note that this function does not look at, or modify, the TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node returned is one of the elements of INSTANTIATIONS, callers may store information in the TREE_PURPOSE or TREE_TYPE of the nodes, and retrieve it from the value returned. */ tree most_specialized_instantiation (tree templates) { tree fn, champ; ++processing_template_decl; champ = templates; for (fn = TREE_CHAIN (templates); fn; fn = TREE_CHAIN (fn)) { int fate = 0; if (get_bindings (TREE_VALUE (champ), DECL_TEMPLATE_RESULT (TREE_VALUE (fn)), NULL_TREE, /*check_ret=*/false)) fate--; if (get_bindings (TREE_VALUE (fn), DECL_TEMPLATE_RESULT (TREE_VALUE (champ)), NULL_TREE, /*check_ret=*/false)) fate++; if (fate == -1) champ = fn; else if (!fate) { /* Equally specialized, move to next function. If there is no next function, nothing's most specialized. */ fn = TREE_CHAIN (fn); champ = fn; if (!fn) break; } } if (champ) /* Now verify that champ is better than everything earlier in the instantiation list. */ for (fn = templates; fn != champ; fn = TREE_CHAIN (fn)) if (get_bindings (TREE_VALUE (champ), DECL_TEMPLATE_RESULT (TREE_VALUE (fn)), NULL_TREE, /*check_ret=*/false) || !get_bindings (TREE_VALUE (fn), DECL_TEMPLATE_RESULT (TREE_VALUE (champ)), NULL_TREE, /*check_ret=*/false)) { champ = NULL_TREE; break; } processing_template_decl--; if (!champ) return error_mark_node; return champ; } /* If DECL is a specialization of some template, return the most general such template. Otherwise, returns NULL_TREE. For example, given: template <class T> struct S { template <class U> void f(U); }; if TMPL is `template <class U> void S<int>::f(U)' this will return the full template. This function will not trace past partial specializations, however. For example, given in addition: template <class T> struct S<T*> { template <class U> void f(U); }; if TMPL is `template <class U> void S<int*>::f(U)' this will return `template <class T> template <class U> S<T*>::f(U)'. */ tree most_general_template (tree decl) { /* If DECL is a FUNCTION_DECL, find the TEMPLATE_DECL of which it is an immediate specialization. */ if (TREE_CODE (decl) == FUNCTION_DECL) { if (DECL_TEMPLATE_INFO (decl)) { decl = DECL_TI_TEMPLATE (decl); /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE for a template friend. */ if (TREE_CODE (decl) != TEMPLATE_DECL) return NULL_TREE; } else return NULL_TREE; } /* Look for more and more general templates. */ while (DECL_TEMPLATE_INFO (decl)) { /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases. (See cp-tree.h for details.) */ if (TREE_CODE (DECL_TI_TEMPLATE (decl)) != TEMPLATE_DECL) break; if (CLASS_TYPE_P (TREE_TYPE (decl)) && CLASSTYPE_TEMPLATE_SPECIALIZATION (TREE_TYPE (decl))) break; /* Stop if we run into an explicitly specialized class template. */ if (!DECL_NAMESPACE_SCOPE_P (decl) && DECL_CONTEXT (decl) && CLASSTYPE_TEMPLATE_SPECIALIZATION (DECL_CONTEXT (decl))) break; decl = DECL_TI_TEMPLATE (decl); } return decl; } /* Return the most specialized of the class template partial specializations of TMPL which can produce TYPE, a specialization of TMPL. The value returned is actually a TREE_LIST; the TREE_TYPE is a _TYPE node corresponding to the partial specialization, while the TREE_PURPOSE is the set of template arguments that must be substituted into the TREE_TYPE in order to generate TYPE. If the choice of partial specialization is ambiguous, a diagnostic is issued, and the error_mark_node is returned. If there are no partial specializations of TMPL matching TYPE, then NULL_TREE is returned. */ static tree most_specialized_class (tree type, tree tmpl) { tree list = NULL_TREE; tree t; tree champ; int fate; bool ambiguous_p; tree args; tree outer_args = NULL_TREE; tmpl = most_general_template (tmpl); args = CLASSTYPE_TI_ARGS (type); /* For determining which partial specialization to use, only the innermost args are interesting. */ if (TMPL_ARGS_HAVE_MULTIPLE_LEVELS (args)) { outer_args = strip_innermost_template_args (args, 1); args = INNERMOST_TEMPLATE_ARGS (args); } for (t = DECL_TEMPLATE_SPECIALIZATIONS (tmpl); t; t = TREE_CHAIN (t)) { tree partial_spec_args; tree spec_args; tree parms = TREE_VALUE (t); partial_spec_args = CLASSTYPE_TI_ARGS (TREE_TYPE (t)); ++processing_template_decl; if (outer_args) { int i; /* Discard the outer levels of args, and then substitute in the template args from the enclosing class. */ partial_spec_args = INNERMOST_TEMPLATE_ARGS (partial_spec_args); partial_spec_args = tsubst_template_args (partial_spec_args, outer_args, tf_none, NULL_TREE); /* PARMS already refers to just the innermost parms, but the template parms in partial_spec_args had their levels lowered by tsubst, so we need to do the same for the parm list. We can't just tsubst the TREE_VEC itself, as tsubst wants to treat a TREE_VEC as an argument vector. */ parms = copy_node (parms); for (i = TREE_VEC_LENGTH (parms) - 1; i >= 0; --i) TREE_VEC_ELT (parms, i) = tsubst (TREE_VEC_ELT (parms, i), outer_args, tf_none, NULL_TREE); } partial_spec_args = coerce_template_parms (DECL_INNERMOST_TEMPLATE_PARMS (tmpl), add_to_template_args (outer_args, partial_spec_args), tmpl, tf_none, /*require_all_args=*/true, /*use_default_args=*/true); --processing_template_decl; if (partial_spec_args == error_mark_node) return error_mark_node; spec_args = get_class_bindings (parms, partial_spec_args, args); if (spec_args) { if (outer_args) spec_args = add_to_template_args (outer_args, spec_args); list = tree_cons (spec_args, TREE_VALUE (t), list); TREE_TYPE (list) = TREE_TYPE (t); } } if (! list) return NULL_TREE; ambiguous_p = false; t = list; champ = t; t = TREE_CHAIN (t); for (; t; t = TREE_CHAIN (t)) { fate = more_specialized_class (champ, t); if (fate == 1) ; else { if (fate == 0) { t = TREE_CHAIN (t); if (! t) { ambiguous_p = true; break; } } champ = t; } } if (!ambiguous_p) for (t = list; t && t != champ; t = TREE_CHAIN (t)) { fate = more_specialized_class (champ, t); if (fate != 1) { ambiguous_p = true; break; } } if (ambiguous_p) { const char *str; char *spaces = NULL; error ("ambiguous class template instantiation for %q#T", type); str = TREE_CHAIN (list) ? _("candidates are:") : _("candidate is:"); for (t = list; t; t = TREE_CHAIN (t)) { error ("%s %+#T", spaces ? spaces : str, TREE_TYPE (t)); spaces = spaces ? spaces : get_spaces (str); } free (spaces); return error_mark_node; } return champ; } /* Explicitly instantiate DECL. */ void do_decl_instantiation (tree decl, tree storage) { tree result = NULL_TREE; int extern_p = 0; if (!decl || decl == error_mark_node) /* An error occurred, for which grokdeclarator has already issued an appropriate message. */ return; else if (! DECL_LANG_SPECIFIC (decl)) { error ("explicit instantiation of non-template %q#D", decl); return; } else if (TREE_CODE (decl) == VAR_DECL) { /* There is an asymmetry here in the way VAR_DECLs and FUNCTION_DECLs are handled by grokdeclarator. In the case of the latter, the DECL we get back will be marked as a template instantiation, and the appropriate DECL_TEMPLATE_INFO will be set up. This does not happen for VAR_DECLs so we do the lookup here. Probably, grokdeclarator should handle VAR_DECLs as it currently handles FUNCTION_DECLs. */ if (!DECL_CLASS_SCOPE_P (decl)) { error ("%qD is not a static data member of a class template", decl); return; } result = lookup_field (DECL_CONTEXT (decl), DECL_NAME (decl), 0, false); if (!result || TREE_CODE (result) != VAR_DECL) { error ("no matching template for %qD found", decl); return; } if (!same_type_p (TREE_TYPE (result), TREE_TYPE (decl))) { error ("type %qT for explicit instantiation %qD does not match " "declared type %qT", TREE_TYPE (result), decl, TREE_TYPE (decl)); return; } } else if (TREE_CODE (decl) != FUNCTION_DECL) { error ("explicit instantiation of %q#D", decl); return; } else result = decl; /* Check for various error cases. Note that if the explicit instantiation is valid the RESULT will currently be marked as an *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set until we get here. */ if (DECL_TEMPLATE_SPECIALIZATION (result)) { /* DR 259 [temp.spec]. Both an explicit instantiation and a declaration of an explicit specialization shall not appear in a program unless the explicit instantiation follows a declaration of the explicit specialization. For a given set of template parameters, if an explicit instantiation of a template appears after a declaration of an explicit specialization for that template, the explicit instantiation has no effect. */ return; } else if (DECL_EXPLICIT_INSTANTIATION (result)) { /* [temp.spec] No program shall explicitly instantiate any template more than once. We check DECL_NOT_REALLY_EXTERN so as not to complain when the first instantiation was `extern' and the second is not, and EXTERN_P for the opposite case. */ if (DECL_NOT_REALLY_EXTERN (result) && !extern_p) permerror (input_location, "duplicate explicit instantiation of %q#D", result); /* If an "extern" explicit instantiation follows an ordinary explicit instantiation, the template is instantiated. */ if (extern_p) return; } else if (!DECL_IMPLICIT_INSTANTIATION (result)) { error ("no matching template for %qD found", result); return; } else if (!DECL_TEMPLATE_INFO (result)) { permerror (input_location, "explicit instantiation of non-template %q#D", result); return; } if (storage == NULL_TREE) ; else if (storage == ridpointers[(int) RID_EXTERN]) { if (!in_system_header && (cxx_dialect == cxx98)) pedwarn (input_location, OPT_pedantic, "ISO C++ 1998 forbids the use of %<extern%> on explicit " "instantiations"); extern_p = 1; } else error ("storage class %qD applied to template instantiation", storage); check_explicit_instantiation_namespace (result); mark_decl_instantiated (result, extern_p); if (! extern_p) instantiate_decl (result, /*defer_ok=*/1, /*expl_inst_class_mem_p=*/false); } static void mark_class_instantiated (tree t, int extern_p) { SET_CLASSTYPE_EXPLICIT_INSTANTIATION (t); SET_CLASSTYPE_INTERFACE_KNOWN (t); CLASSTYPE_INTERFACE_ONLY (t) = extern_p; TYPE_DECL_SUPPRESS_DEBUG (TYPE_NAME (t)) = extern_p; if (! extern_p) { CLASSTYPE_DEBUG_REQUESTED (t) = 1; rest_of_type_compilation (t, 1); } } /* Called from do_type_instantiation through binding_table_foreach to do recursive instantiation for the type bound in ENTRY. */ static void bt_instantiate_type_proc (binding_entry entry, void *data) { tree storage = *(tree *) data; if (MAYBE_CLASS_TYPE_P (entry->type) && !uses_template_parms (CLASSTYPE_TI_ARGS (entry->type))) do_type_instantiation (TYPE_MAIN_DECL (entry->type), storage, 0); } /* Called from do_type_instantiation to instantiate a member (a member function or a static member variable) of an explicitly instantiated class template. */ static void instantiate_class_member (tree decl, int extern_p) { mark_decl_instantiated (decl, extern_p); if (! extern_p) instantiate_decl (decl, /*defer_ok=*/1, /*expl_inst_class_mem_p=*/true); } /* Perform an explicit instantiation of template class T. STORAGE, if non-null, is the RID for extern, inline or static. COMPLAIN is nonzero if this is called from the parser, zero if called recursively, since the standard is unclear (as detailed below). */ void do_type_instantiation (tree t, tree storage, tsubst_flags_t complain) { int extern_p = 0; int nomem_p = 0; int static_p = 0; int previous_instantiation_extern_p = 0; if (TREE_CODE (t) == TYPE_DECL) t = TREE_TYPE (t); if (! CLASS_TYPE_P (t) || ! CLASSTYPE_TEMPLATE_INFO (t)) { error ("explicit instantiation of non-template type %qT", t); return; } complete_type (t); if (!COMPLETE_TYPE_P (t)) { if (complain & tf_error) error ("explicit instantiation of %q#T before definition of template", t); return; } if (storage != NULL_TREE) { if (!in_system_header) { if (storage == ridpointers[(int) RID_EXTERN]) { if (cxx_dialect == cxx98) pedwarn (input_location, OPT_pedantic, "ISO C++ 1998 forbids the use of %<extern%> on " "explicit instantiations"); } else pedwarn (input_location, OPT_pedantic, "ISO C++ forbids the use of %qE" " on explicit instantiations", storage); } if (storage == ridpointers[(int) RID_INLINE]) nomem_p = 1; else if (storage == ridpointers[(int) RID_EXTERN]) extern_p = 1; else if (storage == ridpointers[(int) RID_STATIC]) static_p = 1; else { error ("storage class %qD applied to template instantiation", storage); extern_p = 0; } } if (CLASSTYPE_TEMPLATE_SPECIALIZATION (t)) { /* DR 259 [temp.spec]. Both an explicit instantiation and a declaration of an explicit specialization shall not appear in a program unless the explicit instantiation follows a declaration of the explicit specialization. For a given set of template parameters, if an explicit instantiation of a template appears after a declaration of an explicit specialization for that template, the explicit instantiation has no effect. */ return; } else if (CLASSTYPE_EXPLICIT_INSTANTIATION (t)) { /* [temp.spec] No program shall explicitly instantiate any template more than once. If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit instantiation was `extern'. If EXTERN_P then the second is. These cases are OK. */ previous_instantiation_extern_p = CLASSTYPE_INTERFACE_ONLY (t); if (!previous_instantiation_extern_p && !extern_p && (complain & tf_error)) permerror (input_location, "duplicate explicit instantiation of %q#T", t); /* If we've already instantiated the template, just return now. */ if (!CLASSTYPE_INTERFACE_ONLY (t)) return; } check_explicit_instantiation_namespace (TYPE_NAME (t)); mark_class_instantiated (t, extern_p); if (nomem_p) return; { tree tmp; /* In contrast to implicit instantiation, where only the declarations, and not the definitions, of members are instantiated, we have here: [temp.explicit] The explicit instantiation of a class template specialization implies the instantiation of all of its members not previously explicitly specialized in the translation unit containing the explicit instantiation. Of course, we can't instantiate member template classes, since we don't have any arguments for them. Note that the standard is unclear on whether the instantiation of the members are *explicit* instantiations or not. However, the most natural interpretation is that it should be an explicit instantiation. */ if (! static_p) for (tmp = TYPE_METHODS (t); tmp; tmp = TREE_CHAIN (tmp)) if (TREE_CODE (tmp) == FUNCTION_DECL && DECL_TEMPLATE_INSTANTIATION (tmp)) instantiate_class_member (tmp, extern_p); for (tmp = TYPE_FIELDS (t); tmp; tmp = TREE_CHAIN (tmp)) if (TREE_CODE (tmp) == VAR_DECL && DECL_TEMPLATE_INSTANTIATION (tmp)) instantiate_class_member (tmp, extern_p); if (CLASSTYPE_NESTED_UTDS (t)) binding_table_foreach (CLASSTYPE_NESTED_UTDS (t), bt_instantiate_type_proc, &storage); } } /* Given a function DECL, which is a specialization of TMPL, modify DECL to be a re-instantiation of TMPL with the same template arguments. TMPL should be the template into which tsubst'ing should occur for DECL, not the most general template. One reason for doing this is a scenario like this: template <class T> void f(const T&, int i); void g() { f(3, 7); } template <class T> void f(const T& t, const int i) { } Note that when the template is first instantiated, with instantiate_template, the resulting DECL will have no name for the first parameter, and the wrong type for the second. So, when we go to instantiate the DECL, we regenerate it. */ static void regenerate_decl_from_template (tree decl, tree tmpl) { /* The arguments used to instantiate DECL, from the most general template. */ tree args; tree code_pattern; args = DECL_TI_ARGS (decl); code_pattern = DECL_TEMPLATE_RESULT (tmpl); /* Make sure that we can see identifiers, and compute access correctly. */ push_access_scope (decl); if (TREE_CODE (decl) == FUNCTION_DECL) { tree decl_parm; tree pattern_parm; tree specs; int args_depth; int parms_depth; args_depth = TMPL_ARGS_DEPTH (args); parms_depth = TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (tmpl)); if (args_depth > parms_depth) args = get_innermost_template_args (args, parms_depth); specs = tsubst_exception_specification (TREE_TYPE (code_pattern), args, tf_error, NULL_TREE); if (specs) TREE_TYPE (decl) = build_exception_variant (TREE_TYPE (decl), specs); /* Merge parameter declarations. */ decl_parm = skip_artificial_parms_for (decl, DECL_ARGUMENTS (decl)); pattern_parm = skip_artificial_parms_for (code_pattern, DECL_ARGUMENTS (code_pattern)); while (decl_parm && !FUNCTION_PARAMETER_PACK_P (pattern_parm)) { tree parm_type; tree attributes; if (DECL_NAME (decl_parm) != DECL_NAME (pattern_parm)) DECL_NAME (decl_parm) = DECL_NAME (pattern_parm); parm_type = tsubst (TREE_TYPE (pattern_parm), args, tf_error, NULL_TREE); parm_type = type_decays_to (parm_type); if (!same_type_p (TREE_TYPE (decl_parm), parm_type)) TREE_TYPE (decl_parm) = parm_type; attributes = DECL_ATTRIBUTES (pattern_parm); if (DECL_ATTRIBUTES (decl_parm) != attributes) { DECL_ATTRIBUTES (decl_parm) = attributes; cplus_decl_attributes (&decl_parm, attributes, /*flags=*/0); } decl_parm = TREE_CHAIN (decl_parm); pattern_parm = TREE_CHAIN (pattern_parm); } /* Merge any parameters that match with the function parameter pack. */ if (pattern_parm && FUNCTION_PARAMETER_PACK_P (pattern_parm)) { int i, len; tree expanded_types; /* Expand the TYPE_PACK_EXPANSION that provides the types for the parameters in this function parameter pack. */ expanded_types = tsubst_pack_expansion (TREE_TYPE (pattern_parm), args, tf_error, NULL_TREE); len = TREE_VEC_LENGTH (expanded_types); for (i = 0; i < len; i++) { tree parm_type; tree attributes; if (DECL_NAME (decl_parm) != DECL_NAME (pattern_parm)) /* Rename the parameter to include the index. */ DECL_NAME (decl_parm) = make_ith_pack_parameter_name (DECL_NAME (pattern_parm), i); parm_type = TREE_VEC_ELT (expanded_types, i); parm_type = type_decays_to (parm_type); if (!same_type_p (TREE_TYPE (decl_parm), parm_type)) TREE_TYPE (decl_parm) = parm_type; attributes = DECL_ATTRIBUTES (pattern_parm); if (DECL_ATTRIBUTES (decl_parm) != attributes) { DECL_ATTRIBUTES (decl_parm) = attributes; cplus_decl_attributes (&decl_parm, attributes, /*flags=*/0); } decl_parm = TREE_CHAIN (decl_parm); } } /* Merge additional specifiers from the CODE_PATTERN. */ if (DECL_DECLARED_INLINE_P (code_pattern) && !DECL_DECLARED_INLINE_P (decl)) DECL_DECLARED_INLINE_P (decl) = 1; } else if (TREE_CODE (decl) == VAR_DECL) DECL_INITIAL (decl) = tsubst_expr (DECL_INITIAL (code_pattern), args, tf_error, DECL_TI_TEMPLATE (decl), /*integral_constant_expression_p=*/false); else gcc_unreachable (); pop_access_scope (decl); } /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be substituted to get DECL. */ tree template_for_substitution (tree decl) { tree tmpl = DECL_TI_TEMPLATE (decl); /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern for the instantiation. This is not always the most general template. Consider, for example: template <class T> struct S { template <class U> void f(); template <> void f<int>(); }; and an instantiation of S<double>::f<int>. We want TD to be the specialization S<T>::f<int>, not the more general S<T>::f<U>. */ while (/* An instantiation cannot have a definition, so we need a more general template. */ DECL_TEMPLATE_INSTANTIATION (tmpl) /* We must also deal with friend templates. Given: template <class T> struct S { template <class U> friend void f() {}; }; S<int>::f<U> say, is not an instantiation of S<T>::f<U>, so far as the language is concerned, but that's still where we get the pattern for the instantiation from. On other hand, if the definition comes outside the class, say: template <class T> struct S { template <class U> friend void f(); }; template <class U> friend void f() {} we don't need to look any further. That's what the check for DECL_INITIAL is for. */ || (TREE_CODE (decl) == FUNCTION_DECL && DECL_FRIEND_PSEUDO_TEMPLATE_INSTANTIATION (tmpl) && !DECL_INITIAL (DECL_TEMPLATE_RESULT (tmpl)))) { /* The present template, TD, should not be a definition. If it were a definition, we should be using it! Note that we cannot restructure the loop to just keep going until we find a template with a definition, since that might go too far if a specialization was declared, but not defined. */ gcc_assert (TREE_CODE (decl) != VAR_DECL || DECL_IN_AGGR_P (DECL_TEMPLATE_RESULT (tmpl))); /* Fetch the more general template. */ tmpl = DECL_TI_TEMPLATE (tmpl); } return tmpl; } /* Returns true if we need to instantiate this template instance even if we know we aren't going to emit it.. */ bool always_instantiate_p (tree decl) { /* We always instantiate inline functions so that we can inline them. An explicit instantiation declaration prohibits implicit instantiation of non-inline functions. With high levels of optimization, we would normally inline non-inline functions -- but we're not allowed to do that for "extern template" functions. Therefore, we check DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */ return ((TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl)) /* And we need to instantiate static data members so that their initializers are available in integral constant expressions. */ || (TREE_CODE (decl) == VAR_DECL && DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl))); } /* Produce the definition of D, a _DECL generated from a template. If DEFER_OK is nonzero, then we don't have to actually do the instantiation now; we just have to do it sometime. Normally it is an error if this is an explicit instantiation but D is undefined. EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly instantiated class template. */ tree instantiate_decl (tree d, int defer_ok, bool expl_inst_class_mem_p) { tree tmpl = DECL_TI_TEMPLATE (d); tree gen_args; tree args; tree td; tree code_pattern; tree spec; tree gen_tmpl; bool pattern_defined; int need_push; location_t saved_loc = input_location; bool external_p; /* This function should only be used to instantiate templates for functions and static member variables. */ gcc_assert (TREE_CODE (d) == FUNCTION_DECL || TREE_CODE (d) == VAR_DECL); /* Variables are never deferred; if instantiation is required, they are instantiated right away. That allows for better code in the case that an expression refers to the value of the variable -- if the variable has a constant value the referring expression can take advantage of that fact. */ if (TREE_CODE (d) == VAR_DECL) defer_ok = 0; /* Don't instantiate cloned functions. Instead, instantiate the functions they cloned. */ if (TREE_CODE (d) == FUNCTION_DECL && DECL_CLONED_FUNCTION_P (d)) d = DECL_CLONED_FUNCTION (d); if (DECL_TEMPLATE_INSTANTIATED (d) || DECL_TEMPLATE_SPECIALIZATION (d)) /* D has already been instantiated or explicitly specialized, so there's nothing for us to do here. It might seem reasonable to check whether or not D is an explicit instantiation, and, if so, stop here. But when an explicit instantiation is deferred until the end of the compilation, DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do the instantiation. */ return d; /* Check to see whether we know that this template will be instantiated in some other file, as with "extern template" extension. */ external_p = (DECL_INTERFACE_KNOWN (d) && DECL_REALLY_EXTERN (d)); /* In general, we do not instantiate such templates. */ if (external_p && !always_instantiate_p (d)) return d; gen_tmpl = most_general_template (tmpl); gen_args = DECL_TI_ARGS (d); if (tmpl != gen_tmpl) /* We should already have the extra args. */ gcc_assert (TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (gen_tmpl)) == TMPL_ARGS_DEPTH (gen_args)); /* And what's in the hash table should match D. */ gcc_assert ((spec = retrieve_specialization (gen_tmpl, gen_args, 0)) == d || spec == NULL_TREE); /* This needs to happen before any tsubsting. */ if (! push_tinst_level (d)) return d; timevar_push (TV_PARSE); /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern for the instantiation. */ td = template_for_substitution (d); code_pattern = DECL_TEMPLATE_RESULT (td); /* We should never be trying to instantiate a member of a class template or partial specialization. */ gcc_assert (d != code_pattern); if ((DECL_NAMESPACE_SCOPE_P (d) && !DECL_INITIALIZED_IN_CLASS_P (d)) || DECL_TEMPLATE_SPECIALIZATION (td)) /* In the case of a friend template whose definition is provided outside the class, we may have too many arguments. Drop the ones we don't need. The same is true for specializations. */ args = get_innermost_template_args (gen_args, TMPL_PARMS_DEPTH (DECL_TEMPLATE_PARMS (td))); else args = gen_args; if (TREE_CODE (d) == FUNCTION_DECL) pattern_defined = (DECL_SAVED_TREE (code_pattern) != NULL_TREE); else pattern_defined = ! DECL_IN_AGGR_P (code_pattern); /* We may be in the middle of deferred access check. Disable it now. */ push_deferring_access_checks (dk_no_deferred); /* Unless an explicit instantiation directive has already determined the linkage of D, remember that a definition is available for this entity. */ if (pattern_defined && !DECL_INTERFACE_KNOWN (d) && !DECL_NOT_REALLY_EXTERN (d)) mark_definable (d); input_location = DECL_SOURCE_LOCATION (d); /* If D is a member of an explicitly instantiated class template, and no definition is available, treat it like an implicit instantiation. */ if (!pattern_defined && expl_inst_class_mem_p && DECL_EXPLICIT_INSTANTIATION (d)) { DECL_NOT_REALLY_EXTERN (d) = 0; DECL_INTERFACE_KNOWN (d) = 0; SET_DECL_IMPLICIT_INSTANTIATION (d); } /* Recheck the substitutions to obtain any warning messages about ignoring cv qualifiers. Don't do this for artificial decls, as it breaks the context-sensitive substitution for lambda op(). */ if (!defer_ok && !DECL_ARTIFICIAL (d)) { tree gen = DECL_TEMPLATE_RESULT (gen_tmpl); tree type = TREE_TYPE (gen); /* Make sure that we can see identifiers, and compute access correctly. D is already the target FUNCTION_DECL with the right context. */ push_access_scope (d); if (TREE_CODE (gen) == FUNCTION_DECL) { tsubst (DECL_ARGUMENTS (gen), gen_args, tf_warning_or_error, d); tsubst_exception_specification (type, gen_args, tf_warning_or_error, d); /* Don't simply tsubst the function type, as that will give duplicate warnings about poor parameter qualifications. The function arguments are the same as the decl_arguments without the top level cv qualifiers. */ type = TREE_TYPE (type); } tsubst (type, gen_args, tf_warning_or_error, d); pop_access_scope (d); } /* Defer all other templates, unless we have been explicitly forbidden from doing so. */ if (/* If there is no definition, we cannot instantiate the template. */ ! pattern_defined /* If it's OK to postpone instantiation, do so. */ || defer_ok /* If this is a static data member that will be defined elsewhere, we don't want to instantiate the entire data member, but we do want to instantiate the initializer so that we can substitute that elsewhere. */ || (external_p && TREE_CODE (d) == VAR_DECL)) { /* The definition of the static data member is now required so we must substitute the initializer. */ if (TREE_CODE (d) == VAR_DECL && !DECL_INITIAL (d) && DECL_INITIAL (code_pattern)) { tree ns; tree init; ns = decl_namespace_context (d); push_nested_namespace (ns); push_nested_class (DECL_CONTEXT (d)); init = tsubst_expr (DECL_INITIAL (code_pattern), args, tf_warning_or_error, NULL_TREE, /*integral_constant_expression_p=*/false); cp_finish_decl (d, init, /*init_const_expr_p=*/false, /*asmspec_tree=*/NULL_TREE, LOOKUP_ONLYCONVERTING); pop_nested_class (); pop_nested_namespace (ns); } /* We restore the source position here because it's used by add_pending_template. */ input_location = saved_loc; if (at_eof && !pattern_defined && DECL_EXPLICIT_INSTANTIATION (d) && DECL_NOT_REALLY_EXTERN (d)) /* [temp.explicit] The definition of a non-exported function template, a non-exported member function template, or a non-exported member function or static data member of a class template shall be present in every translation unit in which it is explicitly instantiated. */ permerror (input_location, "explicit instantiation of %qD " "but no definition available", d); /* ??? Historically, we have instantiated inline functions, even when marked as "extern template". */ if (!(external_p && TREE_CODE (d) == VAR_DECL)) add_pending_template (d); goto out; } /* Tell the repository that D is available in this translation unit -- and see if it is supposed to be instantiated here. */ if (TREE_PUBLIC (d) && !DECL_REALLY_EXTERN (d) && !repo_emit_p (d)) { /* In a PCH file, despite the fact that the repository hasn't requested instantiation in the PCH it is still possible that an instantiation will be required in a file that includes the PCH. */ if (pch_file) add_pending_template (d); /* Instantiate inline functions so that the inliner can do its job, even though we'll not be emitting a copy of this function. */ if (!(TREE_CODE (d) == FUNCTION_DECL && possibly_inlined_p (d))) goto out; } need_push = !cfun || !global_bindings_p (); if (need_push) push_to_top_level (); /* Mark D as instantiated so that recursive calls to instantiate_decl do not try to instantiate it again. */ DECL_TEMPLATE_INSTANTIATED (d) = 1; /* Regenerate the declaration in case the template has been modified by a subsequent redeclaration. */ regenerate_decl_from_template (d, td); /* We already set the file and line above. Reset them now in case they changed as a result of calling regenerate_decl_from_template. */ input_location = DECL_SOURCE_LOCATION (d); if (TREE_CODE (d) == VAR_DECL) { tree init; /* Clear out DECL_RTL; whatever was there before may not be right since we've reset the type of the declaration. */ SET_DECL_RTL (d, NULL_RTX); DECL_IN_AGGR_P (d) = 0; /* The initializer is placed in DECL_INITIAL by regenerate_decl_from_template. Pull it out so that cp_finish_decl can process it. */ init = DECL_INITIAL (d); DECL_INITIAL (d) = NULL_TREE; DECL_INITIALIZED_P (d) = 0; /* Clear DECL_EXTERNAL so that cp_finish_decl will process the initializer. That function will defer actual emission until we have a chance to determine linkage. */ DECL_EXTERNAL (d) = 0; /* Enter the scope of D so that access-checking works correctly. */ push_nested_class (DECL_CONTEXT (d)); cp_finish_decl (d, init, false, NULL_TREE, 0); pop_nested_class (); } else if (TREE_CODE (d) == FUNCTION_DECL) { htab_t saved_local_specializations; tree subst_decl; tree tmpl_parm; tree spec_parm; /* Save away the current list, in case we are instantiating one template from within the body of another. */ saved_local_specializations = local_specializations; /* Set up the list of local specializations. */ local_specializations = htab_create (37, hash_local_specialization, eq_local_specializations, NULL); /* Set up context. */ start_preparsed_function (d, NULL_TREE, SF_PRE_PARSED); /* Create substitution entries for the parameters. */ subst_decl = DECL_TEMPLATE_RESULT (template_for_substitution (d)); tmpl_parm = DECL_ARGUMENTS (subst_decl); spec_parm = DECL_ARGUMENTS (d); if (DECL_NONSTATIC_MEMBER_FUNCTION_P (d)) { register_local_specialization (spec_parm, tmpl_parm); spec_parm = skip_artificial_parms_for (d, spec_parm); tmpl_parm = skip_artificial_parms_for (subst_decl, tmpl_parm); } while (tmpl_parm && !FUNCTION_PARAMETER_PACK_P (tmpl_parm)) { register_local_specialization (spec_parm, tmpl_parm); tmpl_parm = TREE_CHAIN (tmpl_parm); spec_parm = TREE_CHAIN (spec_parm); } if (tmpl_parm && FUNCTION_PARAMETER_PACK_P (tmpl_parm)) { /* Register the (value) argument pack as a specialization of TMPL_PARM, then move on. */ tree argpack = make_fnparm_pack (spec_parm); register_local_specialization (argpack, tmpl_parm); tmpl_parm = TREE_CHAIN (tmpl_parm); spec_parm = NULL_TREE; } gcc_assert (!spec_parm); /* Substitute into the body of the function. */ tsubst_expr (DECL_SAVED_TREE (code_pattern), args, tf_warning_or_error, tmpl, /*integral_constant_expression_p=*/false); /* Set the current input_location to the end of the function so that finish_function knows where we are. */ input_location = DECL_STRUCT_FUNCTION (code_pattern)->function_end_locus; /* We don't need the local specializations any more. */ htab_delete (local_specializations); local_specializations = saved_local_specializations; /* Finish the function. */ d = finish_function (0); expand_or_defer_fn (d); } /* We're not deferring instantiation any more. */ TI_PENDING_TEMPLATE_FLAG (DECL_TEMPLATE_INFO (d)) = 0; if (need_push) pop_from_top_level (); out: input_location = saved_loc; pop_deferring_access_checks (); pop_tinst_level (); timevar_pop (TV_PARSE); return d; } /* Run through the list of templates that we wish we could instantiate, and instantiate any we can. RETRIES is the number of times we retry pending template instantiation. */ void instantiate_pending_templates (int retries) { int reconsider; location_t saved_loc = input_location; /* Instantiating templates may trigger vtable generation. This in turn may require further template instantiations. We place a limit here to avoid infinite loop. */ if (pending_templates && retries >= max_tinst_depth) { tree decl = pending_templates->tinst->decl; error ("template instantiation depth exceeds maximum of %d" " instantiating %q+D, possibly from virtual table generation" " (use -ftemplate-depth= to increase the maximum)", max_tinst_depth, decl); if (TREE_CODE (decl) == FUNCTION_DECL) /* Pretend that we defined it. */ DECL_INITIAL (decl) = error_mark_node; return; } do { struct pending_template **t = &pending_templates; struct pending_template *last = NULL; reconsider = 0; while (*t) { tree instantiation = reopen_tinst_level ((*t)->tinst); bool complete = false; if (TYPE_P (instantiation)) { tree fn; if (!COMPLETE_TYPE_P (instantiation)) { instantiate_class_template (instantiation); if (CLASSTYPE_TEMPLATE_INSTANTIATION (instantiation)) for (fn = TYPE_METHODS (instantiation); fn; fn = TREE_CHAIN (fn)) if (! DECL_ARTIFICIAL (fn)) instantiate_decl (fn, /*defer_ok=*/0, /*expl_inst_class_mem_p=*/false); if (COMPLETE_TYPE_P (instantiation)) reconsider = 1; } complete = COMPLETE_TYPE_P (instantiation); } else { if (!DECL_TEMPLATE_SPECIALIZATION (instantiation) && !DECL_TEMPLATE_INSTANTIATED (instantiation)) { instantiation = instantiate_decl (instantiation, /*defer_ok=*/0, /*expl_inst_class_mem_p=*/false); if (DECL_TEMPLATE_INSTANTIATED (instantiation)) reconsider = 1; } complete = (DECL_TEMPLATE_SPECIALIZATION (instantiation) || DECL_TEMPLATE_INSTANTIATED (instantiation)); } if (complete) /* If INSTANTIATION has been instantiated, then we don't need to consider it again in the future. */ *t = (*t)->next; else { last = *t; t = &(*t)->next; } tinst_depth = 0; current_tinst_level = NULL; } last_pending_template = last; } while (reconsider); input_location = saved_loc; } /* Substitute ARGVEC into T, which is a list of initializers for either base class or a non-static data member. The TREE_PURPOSEs are DECLs, and the TREE_VALUEs are the initializer values. Used by instantiate_decl. */ static tree tsubst_initializer_list (tree t, tree argvec) { tree inits = NULL_TREE; for (; t; t = TREE_CHAIN (t)) { tree decl; tree init; tree expanded_bases = NULL_TREE; tree expanded_arguments = NULL_TREE; int i, len = 1; if (TREE_CODE (TREE_PURPOSE (t)) == TYPE_PACK_EXPANSION) { tree expr; tree arg; /* Expand the base class expansion type into separate base classes. */ expanded_bases = tsubst_pack_expansion (TREE_PURPOSE (t), argvec, tf_warning_or_error, NULL_TREE); if (expanded_bases == error_mark_node) continue; /* We'll be building separate TREE_LISTs of arguments for each base. */ len = TREE_VEC_LENGTH (expanded_bases); expanded_arguments = make_tree_vec (len); for (i = 0; i < len; i++) TREE_VEC_ELT (expanded_arguments, i) = NULL_TREE; /* Build a dummy EXPR_PACK_EXPANSION that will be used to expand each argument in the TREE_VALUE of t. */ expr = make_node (EXPR_PACK_EXPANSION); PACK_EXPANSION_PARAMETER_PACKS (expr) = PACK_EXPANSION_PARAMETER_PACKS (TREE_PURPOSE (t)); if (TREE_VALUE (t) == void_type_node) /* VOID_TYPE_NODE is used to indicate value-initialization. */ { for (i = 0; i < len; i++) TREE_VEC_ELT (expanded_arguments, i) = void_type_node; } else { /* Substitute parameter packs into each argument in the TREE_LIST. */ in_base_initializer = 1; for (arg = TREE_VALUE (t); arg; arg = TREE_CHAIN (arg)) { tree expanded_exprs; /* Expand the argument. */ SET_PACK_EXPANSION_PATTERN (expr, TREE_VALUE (arg)); expanded_exprs = tsubst_pack_expansion (expr, argvec, tf_warning_or_error, NULL_TREE); if (expanded_exprs == error_mark_node) continue; /* Prepend each of the expanded expressions to the corresponding TREE_LIST in EXPANDED_ARGUMENTS. */ for (i = 0; i < len; i++) { TREE_VEC_ELT (expanded_arguments, i) = tree_cons (NULL_TREE, TREE_VEC_ELT (expanded_exprs, i), TREE_VEC_ELT (expanded_arguments, i)); } } in_base_initializer = 0; /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS, since we built them backwards. */ for (i = 0; i < len; i++) { TREE_VEC_ELT (expanded_arguments, i) = nreverse (TREE_VEC_ELT (expanded_arguments, i)); } } } for (i = 0; i < len; ++i) { if (expanded_bases) { decl = TREE_VEC_ELT (expanded_bases, i); decl = expand_member_init (decl); init = TREE_VEC_ELT (expanded_arguments, i); } else { decl = tsubst_copy (TREE_PURPOSE (t), argvec, tf_warning_or_error, NULL_TREE); decl = expand_member_init (decl); if (decl && !DECL_P (decl)) in_base_initializer = 1; init = tsubst_expr (TREE_VALUE (t), argvec, tf_warning_or_error, NULL_TREE, /*integral_constant_expression_p=*/false); in_base_initializer = 0; } if (decl) { init = build_tree_list (decl, init); TREE_CHAIN (init) = inits; inits = init; } } } return inits; } /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */ static void set_current_access_from_decl (tree decl) { if (TREE_PRIVATE (decl)) current_access_specifier = access_private_node; else if (TREE_PROTECTED (decl)) current_access_specifier = access_protected_node; else current_access_specifier = access_public_node; } /* Instantiate an enumerated type. TAG is the template type, NEWTAG is the instantiation (which should have been created with start_enum) and ARGS are the template arguments to use. */ static void tsubst_enum (tree tag, tree newtag, tree args) { tree e; for (e = TYPE_VALUES (tag); e; e = TREE_CHAIN (e)) { tree value; tree decl; decl = TREE_VALUE (e); /* Note that in a template enum, the TREE_VALUE is the CONST_DECL, not the corresponding INTEGER_CST. */ value = tsubst_expr (DECL_INITIAL (decl), args, tf_warning_or_error, NULL_TREE, /*integral_constant_expression_p=*/true); /* Give this enumeration constant the correct access. */ set_current_access_from_decl (decl); /* Actually build the enumerator itself. */ build_enumerator (DECL_NAME (decl), value, newtag); } finish_enum (newtag); DECL_SOURCE_LOCATION (TYPE_NAME (newtag)) = DECL_SOURCE_LOCATION (TYPE_NAME (tag)); } /* DECL is a FUNCTION_DECL that is a template specialization. Return its type -- but without substituting the innermost set of template arguments. So, innermost set of template parameters will appear in the type. */ tree get_mostly_instantiated_function_type (tree decl) { tree fn_type; tree tmpl; tree targs; tree tparms; int parm_depth; tmpl = most_general_template (DECL_TI_TEMPLATE (decl)); targs = DECL_TI_ARGS (decl); tparms = DECL_TEMPLATE_PARMS (tmpl); parm_depth = TMPL_PARMS_DEPTH (tparms); /* There should be as many levels of arguments as there are levels of parameters. */ gcc_assert (parm_depth == TMPL_ARGS_DEPTH (targs)); fn_type = TREE_TYPE (tmpl); if (parm_depth == 1) /* No substitution is necessary. */ ; else { int i, save_access_control; tree partial_args; /* Replace the innermost level of the TARGS with NULL_TREEs to let tsubst know not to substitute for those parameters. */ partial_args = make_tree_vec (TREE_VEC_LENGTH (targs)); for (i = 1; i < TMPL_ARGS_DEPTH (targs); ++i) SET_TMPL_ARGS_LEVEL (partial_args, i, TMPL_ARGS_LEVEL (targs, i)); SET_TMPL_ARGS_LEVEL (partial_args, TMPL_ARGS_DEPTH (targs), make_tree_vec (DECL_NTPARMS (tmpl))); /* Disable access control as this function is used only during name-mangling. */ save_access_control = flag_access_control; flag_access_control = 0; ++processing_template_decl; /* Now, do the (partial) substitution to figure out the appropriate function type. */ fn_type = tsubst (fn_type, partial_args, tf_error, NULL_TREE); --processing_template_decl; /* Substitute into the template parameters to obtain the real innermost set of parameters. This step is important if the innermost set of template parameters contains value parameters whose types depend on outer template parameters. */ TREE_VEC_LENGTH (partial_args)--; tparms = tsubst_template_parms (tparms, partial_args, tf_error); flag_access_control = save_access_control; } return fn_type; } /* Return truthvalue if we're processing a template different from the last one involved in diagnostics. */ int problematic_instantiation_changed (void) { return last_template_error_tick != tinst_level_tick; } /* Remember current template involved in diagnostics. */ void record_last_problematic_instantiation (void) { last_template_error_tick = tinst_level_tick; } struct tinst_level * current_instantiation (void) { return current_tinst_level; } /* [temp.param] Check that template non-type parm TYPE is of an allowable type. Return zero for ok, nonzero for disallowed. Issue error and warning messages under control of COMPLAIN. */ static int invalid_nontype_parm_type_p (tree type, tsubst_flags_t complain) { if (INTEGRAL_OR_ENUMERATION_TYPE_P (type)) return 0; else if (POINTER_TYPE_P (type)) return 0; else if (TYPE_PTR_TO_MEMBER_P (type)) return 0; else if (TREE_CODE (type) == TEMPLATE_TYPE_PARM) return 0; else if (TREE_CODE (type) == TYPENAME_TYPE) return 0; if (complain & tf_error) error ("%q#T is not a valid type for a template constant parameter", type); return 1; } /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type]. Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/ static bool dependent_type_p_r (tree type) { tree scope; /* [temp.dep.type] A type is dependent if it is: -- a template parameter. Template template parameters are types for us (since TYPE_P holds true for them) so we handle them here. */ if (TREE_CODE (type) == TEMPLATE_TYPE_PARM || TREE_CODE (type) == TEMPLATE_TEMPLATE_PARM) return true; /* -- a qualified-id with a nested-name-specifier which contains a class-name that names a dependent type or whose unqualified-id names a dependent type. */ if (TREE_CODE (type) == TYPENAME_TYPE) return true; /* -- a cv-qualified type where the cv-unqualified type is dependent. */ type = TYPE_MAIN_VARIANT (type); /* -- a compound type constructed from any dependent type. */ if (TYPE_PTR_TO_MEMBER_P (type)) return (dependent_type_p (TYPE_PTRMEM_CLASS_TYPE (type)) || dependent_type_p (TYPE_PTRMEM_POINTED_TO_TYPE (type))); else if (TREE_CODE (type) == POINTER_TYPE || TREE_CODE (type) == REFERENCE_TYPE) return dependent_type_p (TREE_TYPE (type)); else if (TREE_CODE (type) == FUNCTION_TYPE || TREE_CODE (type) == METHOD_TYPE) { tree arg_type; if (dependent_type_p (TREE_TYPE (type))) return true; for (arg_type = TYPE_ARG_TYPES (type); arg_type; arg_type = TREE_CHAIN (arg_type)) if (dependent_type_p (TREE_VALUE (arg_type))) return true; return false; } /* -- an array type constructed from any dependent type or whose size is specified by a constant expression that is value-dependent. */ if (TREE_CODE (type) == ARRAY_TYPE) { if (TYPE_DOMAIN (type) && dependent_type_p (TYPE_DOMAIN (type))) return true; return dependent_type_p (TREE_TYPE (type)); } else if (TREE_CODE (type) == INTEGER_TYPE && !TREE_CONSTANT (TYPE_MAX_VALUE (type))) { /* If this is the TYPE_DOMAIN of an array type, consider it dependent. We already checked for value-dependence in compute_array_index_type. */ return type_dependent_expression_p (TYPE_MAX_VALUE (type)); } /* -- a template-id in which either the template name is a template parameter ... */ if (TREE_CODE (type) == BOUND_TEMPLATE_TEMPLATE_PARM) return true; /* ... or any of the template arguments is a dependent type or an expression that is type-dependent or value-dependent. */ else if (CLASS_TYPE_P (type) && CLASSTYPE_TEMPLATE_INFO (type) && (any_dependent_template_arguments_p (INNERMOST_TEMPLATE_ARGS (CLASSTYPE_TI_ARGS (type))))) return true; /* All TYPEOF_TYPEs and DECLTYPE_TYPEs are dependent; if the argument of the `typeof' expression is not type-dependent, then it should already been have resolved. */ if (TREE_CODE (type) == TYPEOF_TYPE || TREE_CODE (type) == DECLTYPE_TYPE) return true; /* A template argument pack is dependent if any of its packed arguments are. */ if (TREE_CODE (type) == TYPE_ARGUMENT_PACK) { tree args = ARGUMENT_PACK_ARGS (type); int i, len = TREE_VEC_LENGTH (args); for (i = 0; i < len; ++i) if (dependent_template_arg_p (TREE_VEC_ELT (args, i))) return true; } /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must be template parameters. */ if (TREE_CODE (type) == TYPE_PACK_EXPANSION) return true; /* The standard does not specifically mention types that are local to template functions or local classes, but they should be considered dependent too. For example: template <int I> void f() { enum E { a = I }; S<sizeof (E)> s; } The size of `E' cannot be known until the value of `I' has been determined. Therefore, `E' must be considered dependent. */ scope = TYPE_CONTEXT (type); if (scope && TYPE_P (scope)) return dependent_type_p (scope); else if (scope && TREE_CODE (scope) == FUNCTION_DECL) return type_dependent_expression_p (scope); /* Other types are non-dependent. */ return false; } /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type]. */ bool dependent_type_p (tree type) { /* If there are no template parameters in scope, then there can't be any dependent types. */ if (!processing_template_decl) { /* If we are not processing a template, then nobody should be providing us with a dependent type. */ gcc_assert (type); gcc_assert (TREE_CODE (type) != TEMPLATE_TYPE_PARM || is_auto (type)); return false; } /* If the type is NULL, we have not computed a type for the entity in question; in that case, the type is dependent. */ if (!type) return true; /* Erroneous types can be considered non-dependent. */ if (type == error_mark_node) return false; /* If we have not already computed the appropriate value for TYPE, do so now. */ if (!TYPE_DEPENDENT_P_VALID (type)) { TYPE_DEPENDENT_P (type) = dependent_type_p_r (type); TYPE_DEPENDENT_P_VALID (type) = 1; } return TYPE_DEPENDENT_P (type); } /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any lookup. In other words, a dependent type that is not the current instantiation. */ bool dependent_scope_p (tree scope) { return (scope && TYPE_P (scope) && dependent_type_p (scope) && !currently_open_class (scope)); } /* Returns TRUE if EXPRESSION is dependent, according to CRITERION. */ static bool dependent_scope_ref_p (tree expression, bool criterion (tree)) { tree scope; tree name; gcc_assert (TREE_CODE (expression) == SCOPE_REF); if (!TYPE_P (TREE_OPERAND (expression, 0))) return true; scope = TREE_OPERAND (expression, 0); name = TREE_OPERAND (expression, 1); /* [temp.dep.expr] An id-expression is type-dependent if it contains a nested-name-specifier that contains a class-name that names a dependent type. */ /* The suggested resolution to Core Issue 224 implies that if the qualifying type is the current class, then we must peek inside it. */ if (DECL_P (name) && currently_open_class (scope) && !criterion (name)) return false; if (dependent_type_p (scope)) return true; return false; } /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of [temp.dep.constexpr]. EXPRESSION is already known to be a constant expression. */ bool value_dependent_expression_p (tree expression) { if (!processing_template_decl) return false; /* A name declared with a dependent type. */ if (DECL_P (expression) && type_dependent_expression_p (expression)) return true; switch (TREE_CODE (expression)) { case IDENTIFIER_NODE: /* A name that has not been looked up -- must be dependent. */ return true; case TEMPLATE_PARM_INDEX: /* A non-type template parm. */ return true; case CONST_DECL: /* A non-type template parm. */ if (DECL_TEMPLATE_PARM_P (expression)) return true; return value_dependent_expression_p (DECL_INITIAL (expression)); case VAR_DECL: /* A constant with integral or enumeration type and is initialized with an expression that is value-dependent. */ if (DECL_INITIAL (expression) && INTEGRAL_OR_ENUMERATION_TYPE_P (TREE_TYPE (expression)) && value_dependent_expression_p (DECL_INITIAL (expression))) return true; return false; case DYNAMIC_CAST_EXPR: case STATIC_CAST_EXPR: case CONST_CAST_EXPR: case REINTERPRET_CAST_EXPR: case CAST_EXPR: /* These expressions are value-dependent if the type to which the cast occurs is dependent or the expression being casted is value-dependent. */ { tree type = TREE_TYPE (expression); if (dependent_type_p (type)) return true; /* A functional cast has a list of operands. */ expression = TREE_OPERAND (expression, 0); if (!expression) { /* If there are no operands, it must be an expression such as "int()". This should not happen for aggregate types because it would form non-constant expressions. */ gcc_assert (INTEGRAL_OR_ENUMERATION_TYPE_P (type)); return false; } if (TREE_CODE (expression) == TREE_LIST) return any_value_dependent_elements_p (expression); return value_dependent_expression_p (expression); } case SIZEOF_EXPR: case ALIGNOF_EXPR: /* A `sizeof' expression is value-dependent if the operand is type-dependent or is a pack expansion. */ expression = TREE_OPERAND (expression, 0); if (PACK_EXPANSION_P (expression)) return true; else if (TYPE_P (expression)) return dependent_type_p (expression); return type_dependent_expression_p (expression); case SCOPE_REF: return dependent_scope_ref_p (expression, value_dependent_expression_p); case COMPONENT_REF: return (value_dependent_expression_p (TREE_OPERAND (expression, 0)) || value_dependent_expression_p (TREE_OPERAND (expression, 1))); case CALL_EXPR: /* A CALL_EXPR may appear in a constant expression if it is a call to a builtin function, e.g., __builtin_constant_p. All such calls are value-dependent. */ return true; case NONTYPE_ARGUMENT_PACK: /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument is value-dependent. */ { tree values = ARGUMENT_PACK_ARGS (expression); int i, len = TREE_VEC_LENGTH (values); for (i = 0; i < len; ++i) if (value_dependent_expression_p (TREE_VEC_ELT (values, i))) return true; return false; } case TRAIT_EXPR: { tree type2 = TRAIT_EXPR_TYPE2 (expression); return (dependent_type_p (TRAIT_EXPR_TYPE1 (expression)) || (type2 ? dependent_type_p (type2) : false)); } case MODOP_EXPR: return ((value_dependent_expression_p (TREE_OPERAND (expression, 0))) || (value_dependent_expression_p (TREE_OPERAND (expression, 2)))); case ADDR_EXPR: { tree op = TREE_OPERAND (expression, 0); return (value_dependent_expression_p (op) || has_value_dependent_address (op)); } default: /* A constant expression is value-dependent if any subexpression is value-dependent. */ switch (TREE_CODE_CLASS (TREE_CODE (expression))) { case tcc_reference: case tcc_unary: return (value_dependent_expression_p (TREE_OPERAND (expression, 0))); case tcc_comparison: case tcc_binary: return ((value_dependent_expression_p (TREE_OPERAND (expression, 0))) || (value_dependent_expression_p (TREE_OPERAND (expression, 1)))); case tcc_expression: case tcc_vl_exp: { int i; for (i = 0; i < TREE_OPERAND_LENGTH (expression); ++i) /* In some cases, some of the operands may be missing. (For example, in the case of PREDECREMENT_EXPR, the amount to increment by may be missing.) That doesn't make the expression dependent. */ if (TREE_OPERAND (expression, i) && (value_dependent_expression_p (TREE_OPERAND (expression, i)))) return true; return false; } default: break; } } /* The expression is not value-dependent. */ return false; } /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of [temp.dep.expr]. */ bool type_dependent_expression_p (tree expression) { if (!processing_template_decl) return false; if (expression == error_mark_node) return false; /* An unresolved name is always dependent. */ if (TREE_CODE (expression) == IDENTIFIER_NODE || TREE_CODE (expression) == USING_DECL) return true; /* Some expression forms are never type-dependent. */ if (TREE_CODE (expression) == PSEUDO_DTOR_EXPR || TREE_CODE (expression) == SIZEOF_EXPR || TREE_CODE (expression) == ALIGNOF_EXPR || TREE_CODE (expression) == TRAIT_EXPR || TREE_CODE (expression) == TYPEID_EXPR || TREE_CODE (expression) == DELETE_EXPR || TREE_CODE (expression) == VEC_DELETE_EXPR || TREE_CODE (expression) == THROW_EXPR) return false; /* The types of these expressions depends only on the type to which the cast occurs. */ if (TREE_CODE (expression) == DYNAMIC_CAST_EXPR || TREE_CODE (expression) == STATIC_CAST_EXPR || TREE_CODE (expression) == CONST_CAST_EXPR || TREE_CODE (expression) == REINTERPRET_CAST_EXPR || TREE_CODE (expression) == CAST_EXPR) return dependent_type_p (TREE_TYPE (expression)); /* The types of these expressions depends only on the type created by the expression. */ if (TREE_CODE (expression) == NEW_EXPR || TREE_CODE (expression) == VEC_NEW_EXPR) { /* For NEW_EXPR tree nodes created inside a template, either the object type itself or a TREE_LIST may appear as the operand 1. */ tree type = TREE_OPERAND (expression, 1); if (TREE_CODE (type) == TREE_LIST) /* This is an array type. We need to check array dimensions as well. */ return dependent_type_p (TREE_VALUE (TREE_PURPOSE (type))) || value_dependent_expression_p (TREE_OPERAND (TREE_VALUE (type), 1)); else return dependent_type_p (type); } if (TREE_CODE (expression) == SCOPE_REF && dependent_scope_ref_p (expression, type_dependent_expression_p)) return true; if (TREE_CODE (expression) == FUNCTION_DECL && DECL_LANG_SPECIFIC (expression) && DECL_TEMPLATE_INFO (expression) && (any_dependent_template_arguments_p (INNERMOST_TEMPLATE_ARGS (DECL_TI_ARGS (expression))))) return true; if (TREE_CODE (expression) == TEMPLATE_DECL && !DECL_TEMPLATE_TEMPLATE_PARM_P (expression)) return false; if (TREE_CODE (expression) == STMT_EXPR) expression = stmt_expr_value_expr (expression); if (BRACE_ENCLOSED_INITIALIZER_P (expression)) { tree elt; unsigned i; FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (expression), i, elt) { if (type_dependent_expression_p (elt)) return true; } return false; } if (TREE_TYPE (expression) == unknown_type_node) { if (TREE_CODE (expression) == ADDR_EXPR) return type_dependent_expression_p (TREE_OPERAND (expression, 0)); if (TREE_CODE (expression) == COMPONENT_REF || TREE_CODE (expression) == OFFSET_REF) { if (type_dependent_expression_p (TREE_OPERAND (expression, 0))) return true; expression = TREE_OPERAND (expression, 1); if (TREE_CODE (expression) == IDENTIFIER_NODE) return false; } /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */ if (TREE_CODE (expression) == SCOPE_REF) return false; if (TREE_CODE (expression) == BASELINK) expression = BASELINK_FUNCTIONS (expression); if (TREE_CODE (expression) == TEMPLATE_ID_EXPR) { if (any_dependent_template_arguments_p (TREE_OPERAND (expression, 1))) return true; expression = TREE_OPERAND (expression, 0); } gcc_assert (TREE_CODE (expression) == OVERLOAD || TREE_CODE (expression) == FUNCTION_DECL); while (expression) { if (type_dependent_expression_p (OVL_CURRENT (expression))) return true; expression = OVL_NEXT (expression); } return false; } gcc_assert (TREE_CODE (expression) != TYPE_DECL); return (dependent_type_p (TREE_TYPE (expression))); } /* Like type_dependent_expression_p, but it also works while not processing a template definition, i.e. during substitution or mangling. */ bool type_dependent_expression_p_push (tree expr) { bool b; ++processing_template_decl; b = type_dependent_expression_p (expr); --processing_template_decl; return b; } /* Returns TRUE if ARGS contains a type-dependent expression. */ bool any_type_dependent_arguments_p (const VEC(tree,gc) *args) { unsigned int i; tree arg; for (i = 0; VEC_iterate (tree, args, i, arg); ++i) { if (type_dependent_expression_p (arg)) return true; } return false; } /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are expressions) contains any value-dependent expressions. */ bool any_value_dependent_elements_p (const_tree list) { for (; list; list = TREE_CHAIN (list)) if (value_dependent_expression_p (TREE_VALUE (list))) return true; return false; } /* Returns TRUE if the ARG (a template argument) is dependent. */ bool dependent_template_arg_p (tree arg) { if (!processing_template_decl) return false; if (TREE_CODE (arg) == TEMPLATE_DECL || TREE_CODE (arg) == TEMPLATE_TEMPLATE_PARM) return dependent_template_p (arg); else if (ARGUMENT_PACK_P (arg)) { tree args = ARGUMENT_PACK_ARGS (arg); int i, len = TREE_VEC_LENGTH (args); for (i = 0; i < len; ++i) { if (dependent_template_arg_p (TREE_VEC_ELT (args, i))) return true; } return false; } else if (TYPE_P (arg)) return dependent_type_p (arg); else return (type_dependent_expression_p (arg) || value_dependent_expression_p (arg)); } /* Returns true if ARGS (a collection of template arguments) contains any types that require structural equality testing. */ bool any_template_arguments_need_structural_equality_p (tree args) { int i; int j; if (!args) return false; if (args == error_mark_node) return true; for (i = 0; i < TMPL_ARGS_DEPTH (args); ++i) { tree level = TMPL_ARGS_LEVEL (args, i + 1); for (j = 0; j < TREE_VEC_LENGTH (level); ++j) { tree arg = TREE_VEC_ELT (level, j); tree packed_args = NULL_TREE; int k, len = 1; if (ARGUMENT_PACK_P (arg)) { /* Look inside the argument pack. */ packed_args = ARGUMENT_PACK_ARGS (arg); len = TREE_VEC_LENGTH (packed_args); } for (k = 0; k < len; ++k) { if (packed_args) arg = TREE_VEC_ELT (packed_args, k); if (error_operand_p (arg)) return true; else if (TREE_CODE (arg) == TEMPLATE_DECL || TREE_CODE (arg) == TEMPLATE_TEMPLATE_PARM) continue; else if (TYPE_P (arg) && TYPE_STRUCTURAL_EQUALITY_P (arg)) return true; else if (!TYPE_P (arg) && TREE_TYPE (arg) && TYPE_STRUCTURAL_EQUALITY_P (TREE_TYPE (arg))) return true; } } } return false; } /* Returns true if ARGS (a collection of template arguments) contains any dependent arguments. */ bool any_dependent_template_arguments_p (const_tree args) { int i; int j; if (!args) return false; if (args == error_mark_node) return true; for (i = 0; i < TMPL_ARGS_DEPTH (args); ++i) { const_tree level = TMPL_ARGS_LEVEL (args, i + 1); for (j = 0; j < TREE_VEC_LENGTH (level); ++j) if (dependent_template_arg_p (TREE_VEC_ELT (level, j))) return true; } return false; } /* Returns TRUE if the template TMPL is dependent. */ bool dependent_template_p (tree tmpl) { if (TREE_CODE (tmpl) == OVERLOAD) { while (tmpl) { if (dependent_template_p (OVL_FUNCTION (tmpl))) return true; tmpl = OVL_CHAIN (tmpl); } return false; } /* Template template parameters are dependent. */ if (DECL_TEMPLATE_TEMPLATE_PARM_P (tmpl) || TREE_CODE (tmpl) == TEMPLATE_TEMPLATE_PARM) return true; /* So are names that have not been looked up. */ if (TREE_CODE (tmpl) == SCOPE_REF || TREE_CODE (tmpl) == IDENTIFIER_NODE) return true; /* So are member templates of dependent classes. */ if (TYPE_P (CP_DECL_CONTEXT (tmpl))) return dependent_type_p (DECL_CONTEXT (tmpl)); return false; } /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */ bool dependent_template_id_p (tree tmpl, tree args) { return (dependent_template_p (tmpl) || any_dependent_template_arguments_p (args)); } /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors is dependent. */ bool dependent_omp_for_p (tree declv, tree initv, tree condv, tree incrv) { int i; if (!processing_template_decl) return false; for (i = 0; i < TREE_VEC_LENGTH (declv); i++) { tree decl = TREE_VEC_ELT (declv, i); tree init = TREE_VEC_ELT (initv, i); tree cond = TREE_VEC_ELT (condv, i); tree incr = TREE_VEC_ELT (incrv, i); if (type_dependent_expression_p (decl)) return true; if (init && type_dependent_expression_p (init)) return true; if (type_dependent_expression_p (cond)) return true; if (COMPARISON_CLASS_P (cond) && (type_dependent_expression_p (TREE_OPERAND (cond, 0)) || type_dependent_expression_p (TREE_OPERAND (cond, 1)))) return true; if (TREE_CODE (incr) == MODOP_EXPR) { if (type_dependent_expression_p (TREE_OPERAND (incr, 0)) || type_dependent_expression_p (TREE_OPERAND (incr, 2))) return true; } else if (type_dependent_expression_p (incr)) return true; else if (TREE_CODE (incr) == MODIFY_EXPR) { if (type_dependent_expression_p (TREE_OPERAND (incr, 0))) return true; else if (BINARY_CLASS_P (TREE_OPERAND (incr, 1))) { tree t = TREE_OPERAND (incr, 1); if (type_dependent_expression_p (TREE_OPERAND (t, 0)) || type_dependent_expression_p (TREE_OPERAND (t, 1))) return true; } } } return false; } /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if no such TYPE can be found. Note that this function peers inside uninstantiated templates and therefore should be used only in extremely limited situations. ONLY_CURRENT_P restricts this peering to the currently open classes hierarchy (which is required when comparing types). */ tree resolve_typename_type (tree type, bool only_current_p) { tree scope; tree name; tree decl; int quals; tree pushed_scope; tree result; gcc_assert (TREE_CODE (type) == TYPENAME_TYPE); scope = TYPE_CONTEXT (type); /* Usually the non-qualified identifier of a TYPENAME_TYPE is TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified identifier of the TYPENAME_TYPE anymore. So by getting the TYPE_IDENTIFIER of the _main declaration_ of the TYPENAME_TYPE instead, we avoid messing up with a possible typedef variant case. */ name = TYPE_IDENTIFIER (TYPE_MAIN_VARIANT (type)); /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve it first before we can figure out what NAME refers to. */ if (TREE_CODE (scope) == TYPENAME_TYPE) scope = resolve_typename_type (scope, only_current_p); /* If we don't know what SCOPE refers to, then we cannot resolve the TYPENAME_TYPE. */ if (TREE_CODE (scope) == TYPENAME_TYPE) return type; /* If the SCOPE is a template type parameter, we have no way of resolving the name. */ if (TREE_CODE (scope) == TEMPLATE_TYPE_PARM) return type; /* If the SCOPE is not the current instantiation, there's no reason to look inside it. */ if (only_current_p && !currently_open_class (scope)) return type; /* If this is a typedef, we don't want to look inside (c++/11987). */ if (typedef_variant_p (type)) return type; /* If SCOPE isn't the template itself, it will not have a valid TYPE_FIELDS list. */ if (same_type_p (scope, CLASSTYPE_PRIMARY_TEMPLATE_TYPE (scope))) /* scope is either the template itself or a compatible instantiation like X<T>, so look up the name in the original template. */ scope = CLASSTYPE_PRIMARY_TEMPLATE_TYPE (scope); else /* scope is a partial instantiation, so we can't do the lookup or we will lose the template arguments. */ return type; /* Enter the SCOPE so that name lookup will be resolved as if we were in the class definition. In particular, SCOPE will no longer be considered a dependent type. */ pushed_scope = push_scope (scope); /* Look up the declaration. */ decl = lookup_member (scope, name, /*protect=*/0, /*want_type=*/true); result = NULL_TREE; /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */ if (!decl) /*nop*/; else if (TREE_CODE (TYPENAME_TYPE_FULLNAME (type)) == IDENTIFIER_NODE && TREE_CODE (decl) == TYPE_DECL) { result = TREE_TYPE (decl); if (result == error_mark_node) result = NULL_TREE; } else if (TREE_CODE (TYPENAME_TYPE_FULLNAME (type)) == TEMPLATE_ID_EXPR && DECL_CLASS_TEMPLATE_P (decl)) { tree tmpl; tree args; /* Obtain the template and the arguments. */ tmpl = TREE_OPERAND (TYPENAME_TYPE_FULLNAME (type), 0); args = TREE_OPERAND (TYPENAME_TYPE_FULLNAME (type), 1); /* Instantiate the template. */ result = lookup_template_class (tmpl, args, NULL_TREE, NULL_TREE, /*entering_scope=*/0, tf_error | tf_user); if (result == error_mark_node) result = NULL_TREE; } /* Leave the SCOPE. */ if (pushed_scope) pop_scope (pushed_scope); /* If we failed to resolve it, return the original typename. */ if (!result) return type; /* If lookup found a typename type, resolve that too. */ if (TREE_CODE (result) == TYPENAME_TYPE && !TYPENAME_IS_RESOLVING_P (result)) { /* Ill-formed programs can cause infinite recursion here, so we must catch that. */ TYPENAME_IS_RESOLVING_P (type) = 1; result = resolve_typename_type (result, only_current_p); TYPENAME_IS_RESOLVING_P (type) = 0; } /* Qualify the resulting type. */ quals = cp_type_quals (type); if (quals) result = cp_build_qualified_type (result, cp_type_quals (result) | quals); return result; } /* EXPR is an expression which is not type-dependent. Return a proxy for EXPR that can be used to compute the types of larger expressions containing EXPR. */ tree build_non_dependent_expr (tree expr) { tree inner_expr; /* Preserve null pointer constants so that the type of things like "p == 0" where "p" is a pointer can be determined. */ if (null_ptr_cst_p (expr)) return expr; /* Preserve OVERLOADs; the functions must be available to resolve types. */ inner_expr = expr; if (TREE_CODE (inner_expr) == STMT_EXPR) inner_expr = stmt_expr_value_expr (inner_expr); if (TREE_CODE (inner_expr) == ADDR_EXPR) inner_expr = TREE_OPERAND (inner_expr, 0); if (TREE_CODE (inner_expr) == COMPONENT_REF) inner_expr = TREE_OPERAND (inner_expr, 1); if (is_overloaded_fn (inner_expr) || TREE_CODE (inner_expr) == OFFSET_REF) return expr; /* There is no need to return a proxy for a variable. */ if (TREE_CODE (expr) == VAR_DECL) return expr; /* Preserve string constants; conversions from string constants to "char *" are allowed, even though normally a "const char *" cannot be used to initialize a "char *". */ if (TREE_CODE (expr) == STRING_CST) return expr; /* Preserve arithmetic constants, as an optimization -- there is no reason to create a new node. */ if (TREE_CODE (expr) == INTEGER_CST || TREE_CODE (expr) == REAL_CST) return expr; /* Preserve THROW_EXPRs -- all throw-expressions have type "void". There is at least one place where we want to know that a particular expression is a throw-expression: when checking a ?: expression, there are special rules if the second or third argument is a throw-expression. */ if (TREE_CODE (expr) == THROW_EXPR) return expr; if (TREE_CODE (expr) == COND_EXPR) return build3 (COND_EXPR, TREE_TYPE (expr), TREE_OPERAND (expr, 0), (TREE_OPERAND (expr, 1) ? build_non_dependent_expr (TREE_OPERAND (expr, 1)) : build_non_dependent_expr (TREE_OPERAND (expr, 0))), build_non_dependent_expr (TREE_OPERAND (expr, 2))); if (TREE_CODE (expr) == COMPOUND_EXPR && !COMPOUND_EXPR_OVERLOADED (expr)) return build2 (COMPOUND_EXPR, TREE_TYPE (expr), TREE_OPERAND (expr, 0), build_non_dependent_expr (TREE_OPERAND (expr, 1))); /* If the type is unknown, it can't really be non-dependent */ gcc_assert (TREE_TYPE (expr) != unknown_type_node); /* Otherwise, build a NON_DEPENDENT_EXPR. REFERENCE_TYPEs are not stripped for expressions in templates because doing so would play havoc with mangling. Consider, for example: template <typename T> void f<T& g>() { g(); } In the body of "f", the expression for "g" will have REFERENCE_TYPE, even though the standard says that it should not. The reason is that we must preserve the syntactic form of the expression so that mangling (say) "f<g>" inside the body of "f" works out correctly. Therefore, the REFERENCE_TYPE is stripped here. */ return build1 (NON_DEPENDENT_EXPR, non_reference (TREE_TYPE (expr)), expr); } /* ARGS is a vector of expressions as arguments to a function call. Replace the arguments with equivalent non-dependent expressions. This modifies ARGS in place. */ void make_args_non_dependent (VEC(tree,gc) *args) { unsigned int ix; tree arg; for (ix = 0; VEC_iterate (tree, args, ix, arg); ++ix) { tree newarg = build_non_dependent_expr (arg); if (newarg != arg) VEC_replace (tree, args, ix, newarg); } } /* Returns a type which represents 'auto'. We use a TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms. */ tree make_auto (void) { tree au = cxx_make_type (TEMPLATE_TYPE_PARM); TYPE_NAME (au) = build_decl (BUILTINS_LOCATION, TYPE_DECL, get_identifier ("auto"), au); TYPE_STUB_DECL (au) = TYPE_NAME (au); TEMPLATE_TYPE_PARM_INDEX (au) = build_template_parm_index (0, processing_template_decl + 1, processing_template_decl + 1, TYPE_NAME (au), NULL_TREE); TYPE_CANONICAL (au) = canonical_type_parameter (au); DECL_ARTIFICIAL (TYPE_NAME (au)) = 1; SET_DECL_TEMPLATE_PARM_P (TYPE_NAME (au)); return au; } /* Given type ARG, return std::initializer_list<ARG>. */ static tree listify (tree arg) { tree std_init_list = namespace_binding (get_identifier ("initializer_list"), std_node); tree argvec; if (!std_init_list || !DECL_CLASS_TEMPLATE_P (std_init_list)) { error ("deducing from brace-enclosed initializer list requires " "#include <initializer_list>"); return error_mark_node; } argvec = make_tree_vec (1); TREE_VEC_ELT (argvec, 0) = arg; return lookup_template_class (std_init_list, argvec, NULL_TREE, NULL_TREE, 0, tf_warning_or_error); } /* Replace auto in TYPE with std::initializer_list<auto>. */ static tree listify_autos (tree type, tree auto_node) { tree init_auto = listify (auto_node); tree argvec = make_tree_vec (1); TREE_VEC_ELT (argvec, 0) = init_auto; if (processing_template_decl) argvec = add_to_template_args (current_template_args (), argvec); return tsubst (type, argvec, tf_warning_or_error, NULL_TREE); } /* walk_tree helper for do_auto_deduction. */ static tree contains_auto_r (tree *tp, int *walk_subtrees ATTRIBUTE_UNUSED, void *type) { /* Is this a variable with the type we're looking for? */ if (DECL_P (*tp) && TREE_TYPE (*tp) == type) return *tp; else return NULL_TREE; } /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */ tree do_auto_deduction (tree type, tree init, tree auto_node) { tree parms, tparms, targs; tree args[1]; tree decl; int val; /* The name of the object being declared shall not appear in the initializer expression. */ decl = cp_walk_tree_without_duplicates (&init, contains_auto_r, type); if (decl) { error ("variable %q#D with %<auto%> type used in its own " "initializer", decl); return error_mark_node; } /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto with either a new invented type template parameter U or, if the initializer is a braced-init-list (8.5.4), with std::initializer_list<U>. */ if (BRACE_ENCLOSED_INITIALIZER_P (init)) type = listify_autos (type, auto_node); parms = build_tree_list (NULL_TREE, type); args[0] = init; tparms = make_tree_vec (1); targs = make_tree_vec (1); TREE_VEC_ELT (tparms, 0) = build_tree_list (NULL_TREE, TYPE_NAME (auto_node)); val = type_unification_real (tparms, targs, parms, args, 1, 0, DEDUCE_CALL, LOOKUP_NORMAL); if (val > 0) { error ("unable to deduce %qT from %qE", type, init); return error_mark_node; } /* If the list of declarators contains more than one declarator, the type of each declared variable is determined as described above. If the type deduced for the template parameter U is not the same in each deduction, the program is ill-formed. */ if (TREE_TYPE (auto_node) && !same_type_p (TREE_TYPE (auto_node), TREE_VEC_ELT (targs, 0))) { error ("inconsistent deduction for %qT: %qT and then %qT", auto_node, TREE_TYPE (auto_node), TREE_VEC_ELT (targs, 0)); return error_mark_node; } TREE_TYPE (auto_node) = TREE_VEC_ELT (targs, 0); if (processing_template_decl) targs = add_to_template_args (current_template_args (), targs); return tsubst (type, targs, tf_warning_or_error, NULL_TREE); } /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the result. */ tree splice_late_return_type (tree type, tree late_return_type) { tree argvec; if (late_return_type == NULL_TREE) return type; argvec = make_tree_vec (1); TREE_VEC_ELT (argvec, 0) = late_return_type; if (processing_template_decl) argvec = add_to_template_args (current_template_args (), argvec); return tsubst (type, argvec, tf_warning_or_error, NULL_TREE); } /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto'. */ bool is_auto (const_tree type) { if (TREE_CODE (type) == TEMPLATE_TYPE_PARM && TYPE_IDENTIFIER (type) == get_identifier ("auto")) return true; else return false; } /* Returns true iff TYPE contains a use of 'auto'. Since auto can only appear as a type-specifier for the declaration in question, we don't have to look through the whole type. */ tree type_uses_auto (tree type) { enum tree_code code; if (is_auto (type)) return type; code = TREE_CODE (type); if (code == POINTER_TYPE || code == REFERENCE_TYPE || code == OFFSET_TYPE || code == FUNCTION_TYPE || code == METHOD_TYPE || code == ARRAY_TYPE) return type_uses_auto (TREE_TYPE (type)); if (TYPE_PTRMEMFUNC_P (type)) return type_uses_auto (TREE_TYPE (TREE_TYPE (TYPE_PTRMEMFUNC_FN_TYPE (type)))); return NULL_TREE; } /* For a given template T, return the vector of typedefs referenced in T for which access check is needed at T instantiation time. T is either a FUNCTION_DECL or a RECORD_TYPE. Those typedefs were added to T by the function append_type_to_template_for_access_check. */ VEC(qualified_typedef_usage_t,gc)* get_types_needing_access_check (tree t) { tree ti; VEC(qualified_typedef_usage_t,gc) *result = NULL; if (!t || t == error_mark_node) return NULL; if (!(ti = get_template_info (t))) return NULL; if (CLASS_TYPE_P (t) || TREE_CODE (t) == FUNCTION_DECL) { if (!TI_TEMPLATE (ti)) return NULL; result = TI_TYPEDEFS_NEEDING_ACCESS_CHECKING (ti); } return result; } /* Append the typedef TYPE_DECL used in template T to a list of typedefs tied to T. That list of typedefs will be access checked at T instantiation time. T is either a FUNCTION_DECL or a RECORD_TYPE. TYPE_DECL is a TYPE_DECL node representing a typedef. SCOPE is the scope through which TYPE_DECL is accessed. LOCATION is the location of the usage point of TYPE_DECL. This function is a subroutine of append_type_to_template_for_access_check. */ static void append_type_to_template_for_access_check_1 (tree t, tree type_decl, tree scope, location_t location) { qualified_typedef_usage_t typedef_usage; tree ti; if (!t || t == error_mark_node) return; gcc_assert ((TREE_CODE (t) == FUNCTION_DECL || CLASS_TYPE_P (t)) && type_decl && TREE_CODE (type_decl) == TYPE_DECL && scope); if (!(ti = get_template_info (t))) return; gcc_assert (TI_TEMPLATE (ti)); typedef_usage.typedef_decl = type_decl; typedef_usage.context = scope; typedef_usage.locus = location; VEC_safe_push (qualified_typedef_usage_t, gc, TI_TYPEDEFS_NEEDING_ACCESS_CHECKING (ti), &typedef_usage); } /* Append TYPE_DECL to the template TEMPL. TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL. At TEMPL instanciation time, TYPE_DECL will be checked to see if it can be accessed through SCOPE. LOCATION is the location of the usage point of TYPE_DECL. e.g. consider the following code snippet: class C { typedef int myint; }; template<class U> struct S { C::myint mi; // <-- usage point of the typedef C::myint }; S<char> s; At S<char> instantiation time, we need to check the access of C::myint In other words, we need to check the access of the myint typedef through the C scope. For that purpose, this function will add the myint typedef and the scope C through which its being accessed to a list of typedefs tied to the template S. That list will be walked at template instantiation time and access check performed on each typedefs it contains. Note that this particular code snippet should yield an error because myint is private to C. */ void append_type_to_template_for_access_check (tree templ, tree type_decl, tree scope, location_t location) { qualified_typedef_usage_t *iter; int i; gcc_assert (type_decl && (TREE_CODE (type_decl) == TYPE_DECL)); /* Make sure we don't append the type to the template twice. */ for (i = 0; VEC_iterate (qualified_typedef_usage_t, get_types_needing_access_check (templ), i, iter); ++i) if (iter->typedef_decl == type_decl && scope == iter->context) return; append_type_to_template_for_access_check_1 (templ, type_decl, scope, location); } /* Set up the hash tables for template instantiations. */ void init_template_processing (void) { decl_specializations = htab_create_ggc (37, hash_specialization, eq_specializations, ggc_free); type_specializations = htab_create_ggc (37, hash_specialization, eq_specializations, ggc_free); } #include "gt-cp-pt.h"
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