+2014-08-01 Braden Obrzut <admin@maniacsvault.net>
+
+ Implement constexpr variable templates
+ * decl.c (grokvardecl): Handle specializations of variable templates.
+ (grokdeclarator): Handle variable template id expressions and NULL_TREE
+ return from grokvardecl.
+ * decl2.c (check_member_template): Allow declaration of template member
+ variables.
+ * parser.c (cp_parser_template_id): Build a TEMPLATE_ID_EXPR for
+ variable templates.
+ * pt.c (check_template_variable): Accept variable temploids at
+ non-class scope.
+ (push_template_decl_real): The current instantiation of a template
+ can be a VAR_DECL.
+ (determine_specialization): Accept variable templates.
+ (check_explicit_specialization): Handle and check for malformed
+ variable template specializations.
+ (lookup_template_variable): New.
+ (tsubst_decl): Handle variable template specializations.
+ (do_decl_instantiation): Handle template variables.
+ (instantiate_decl): Handle template variables.
+ * semantics.c (finish_template_variable): New.
+ (finish_id_expression): Instantiate variable templates.
+ * cp-tree.h (variable_template_p): New.
+
2014-08-02 Paolo Carlini <paolo.carlini@oracle.com>
PR c++/15339
return TREE_TYPE (type_of_this_parm (fntype));
}
+/* True if T designates a variable template declaration. */
+inline bool
+variable_template_p (tree t)
+{
+ if (TREE_CODE (t) != TEMPLATE_DECL)
+ return false;
+ if (tree r = DECL_TEMPLATE_RESULT (t))
+ return VAR_P (r);
+ return false;
+}
+
/* A parameter list indicating for a function with no parameters,
e.g "int f(void)". */
extern cp_parameter_declarator *no_parameters;
extern tree lookup_template_class (tree, tree, tree, tree,
int, tsubst_flags_t);
extern tree lookup_template_function (tree, tree);
+extern tree lookup_template_variable (tree, tree);
extern int uses_template_parms (tree);
extern int uses_template_parms_level (tree, int);
extern bool in_template_function (void);
tsubst_flags_t);
extern tree finish_call_expr (tree, vec<tree, va_gc> **, bool,
bool, tsubst_flags_t);
+extern tree finish_template_variable (tree);
extern tree finish_increment_expr (tree, enum tree_code);
extern tree finish_this_expr (void);
extern tree finish_pseudo_destructor_expr (tree, tree, tree, location_t);
static int unary_op_p (enum tree_code);
static void push_local_name (tree);
static tree grok_reference_init (tree, tree, tree, int);
-static tree grokvardecl (tree, tree, const cp_decl_specifier_seq *,
- int, int, tree);
+static tree grokvardecl (tree, tree, tree, const cp_decl_specifier_seq *,
+ int, int, int, tree);
static int check_static_variable_definition (tree, tree);
static void record_unknown_type (tree, const char *);
static tree builtin_function_1 (tree, tree, bool);
static tree
grokvardecl (tree type,
tree name,
+ tree orig_declarator,
const cp_decl_specifier_seq *declspecs,
int initialized,
int constp,
+ int template_count,
tree scope)
{
tree decl;
|| (TREE_CODE (scope) == NAMESPACE_DECL
&& current_lang_name != lang_name_cplusplus)
/* Similarly for static data members. */
- || TYPE_P (scope)))
+ || TYPE_P (scope)
+ /* Similarly for explicit specializations. */
+ || (orig_declarator
+ && TREE_CODE (orig_declarator) == TEMPLATE_ID_EXPR)))
decl = build_lang_decl (VAR_DECL, name, type);
else
decl = build_decl (input_location, VAR_DECL, name, type);
else
DECL_INTERFACE_KNOWN (decl) = 1;
- return decl;
+ // Handle explicit specializations and instantiations of variable templates.
+ if (orig_declarator)
+ decl = check_explicit_specialization (orig_declarator, decl,
+ template_count, 0);
+
+ return decl != error_mark_node ? decl : NULL_TREE;
}
/* Create and return a canonical pointer to member function type, for
dname = fns;
if (!identifier_p (dname))
{
- gcc_assert (is_overloaded_fn (dname));
- dname = DECL_NAME (get_first_fn (dname));
+ if (variable_template_p (dname))
+ dname = DECL_NAME (dname);
+ else
+ {
+ gcc_assert (is_overloaded_fn (dname));
+ dname = DECL_NAME (get_first_fn (dname));
+ }
}
}
/* Fall through. */
if (unqualified_id && TREE_CODE (unqualified_id) == TEMPLATE_ID_EXPR
&& TREE_CODE (type) != FUNCTION_TYPE
- && TREE_CODE (type) != METHOD_TYPE)
+ && TREE_CODE (type) != METHOD_TYPE
+ && !variable_template_p (TREE_OPERAND (unqualified_id, 0)))
{
error ("template-id %qD used as a declarator",
unqualified_id);
/* It's a variable. */
/* An uninitialized decl with `extern' is a reference. */
- decl = grokvardecl (type, unqualified_id,
+ decl = grokvardecl (type, dname, unqualified_id,
declspecs,
initialized,
(type_quals & TYPE_QUAL_CONST) != 0,
+ template_count,
ctype ? ctype : in_namespace);
+ if (decl == NULL_TREE)
+ return error_mark_node;
+
bad_specifiers (decl, BSP_VAR, virtualp,
memfn_quals != TYPE_UNQUALIFIED,
inlinep, friendp, raises != NULL_TREE);
with member templates. */
DECL_IGNORED_P (tmpl) = 1;
}
+ else if (variable_template_p (tmpl))
+ /* OK */;
else
error ("template declaration of %q#D", decl);
}
template_id
= finish_template_type (templ, arguments, entering_scope);
}
+ else if (variable_template_p (templ))
+ {
+ template_id = lookup_template_variable (templ, arguments);
+ }
else
{
/* If it's not a class-template or a template-template, it should be
if (BASELINK_P (fns))
fns = BASELINK_FUNCTIONS (fns);
- if (!is_overloaded_fn (fns))
+ if (TREE_CODE (decl) == FUNCTION_DECL && !is_overloaded_fn (fns))
{
error ("%qD is not a function template", fns);
return error_mark_node;
}
+ else if (VAR_P (decl) && !variable_template_p (fns))
+ {
+ error ("%qD is not a variable template", fns);
+ return error_mark_node;
+ }
/* Count the number of template headers specified for this
specialization. */
b = b->level_chain)
++header_count;
- for (; fns; fns = OVL_NEXT (fns))
+ if (variable_template_p (fns))
+ templates = tree_cons (explicit_targs, fns, templates);
+ else for (; fns; fns = OVL_NEXT (fns))
{
tree fn = OVL_CURRENT (fns);
tree ctx = CP_DECL_CONTEXT (decl);
int wanted = num_template_headers_for_class (ctx);
if (!TYPE_P (ctx) || !CLASSTYPE_TEMPLATE_INFO (ctx))
- permerror (DECL_SOURCE_LOCATION (decl),
- "%qD is not a static data member of a class template", decl);
- else if (template_header_count > wanted)
+ {
+ if (cxx_dialect < cxx1y)
+ pedwarn (DECL_SOURCE_LOCATION (decl), 0,
+ "variable templates only available with "
+ "-std=c++1y or -std=gnu++1y");
+
+ // Namespace-scope variable templates should have a template header.
+ ++wanted;
+ }
+ if (template_header_count > wanted)
{
bool warned = pedwarn (DECL_SOURCE_LOCATION (decl), 0,
"too many template headers for %D (should be %d)",
/* Fall through. */
case tsk_expl_spec:
+ if (VAR_P (decl) && TREE_CODE (declarator) != TEMPLATE_ID_EXPR)
+ {
+ // In cases like template<> constexpr bool v = true;
+ error ("%qD is not a template variable", dname);
+ break;
+ }
+
SET_DECL_TEMPLATE_SPECIALIZATION (decl);
if (ctype)
member_specialization = 1;
gcc_unreachable ();
}
- if (specialization || member_specialization)
+ if ((specialization || member_specialization)
+ /* This doesn't apply to variable templates. */
+ && (TREE_CODE (TREE_TYPE (decl)) == FUNCTION_TYPE
+ || TREE_CODE (TREE_TYPE (decl)) == METHOD_TYPE))
{
tree t = TYPE_ARG_TYPES (TREE_TYPE (decl));
for (; t; t = TREE_CHAIN (t))
else if (ctype != NULL_TREE
&& (identifier_p (TREE_OPERAND (declarator, 0))))
{
+ // Ignore variable templates.
+ if (VAR_P (decl))
+ return decl;
+
/* Find the list of functions in ctype that have the same
name as the declared function. */
tree name = TREE_OPERAND (declarator, 0);
/* 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)
+ if (DECL_FUNCTION_TEMPLATE_P (tmpl)
+ && DECL_STATIC_FUNCTION_P (tmpl)
&& DECL_NONSTATIC_MEMBER_FUNCTION_P (decl))
revert_static_member_fn (decl);
/* Inherit default function arguments from the template
DECL is specializing. */
- copy_default_args_to_explicit_spec (decl);
+ if (DECL_FUNCTION_TEMPLATE_P (tmpl))
+ copy_default_args_to_explicit_spec (decl);
/* This specialization has the same protection as the
template it specializes. */
/* A 'structor should already have clones. */
gcc_assert (decl == error_mark_node
+ || variable_template_p (tmpl)
|| !(DECL_CONSTRUCTOR_P (decl)
|| DECL_DESTRUCTOR_P (decl))
|| DECL_CLONED_FUNCTION_P (DECL_CHAIN (decl)));
&& TYPE_DECL_ALIAS_P (decl))
/* alias-declaration */
gcc_assert (!DECL_ARTIFICIAL (decl));
+ else if (VAR_P (decl))
+ {
+ if (!DECL_DECLARED_CONSTEXPR_P (decl))
+ {
+ sorry ("template declaration of non-constexpr variable %qD",
+ decl);
+ return error_mark_node;
+ }
+ }
else
{
error ("template declaration of %q#D", decl);
timevar_pop (TV_TEMPLATE_INST);
return ret;
}
+
+/* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
+
+tree
+lookup_template_variable (tree templ, tree arglist)
+{
+ return build2 (TEMPLATE_ID_EXPR, TREE_TYPE (templ), templ, arglist);
+}
\f
struct pair_fn_data
{
if (PRIMARY_TEMPLATE_P (t))
DECL_PRIMARY_TEMPLATE (r) = r;
- if (TREE_CODE (decl) != TYPE_DECL)
+ if (TREE_CODE (decl) != TYPE_DECL && TREE_CODE (decl) != VAR_DECL)
/* Record this non-type partial instantiation. */
register_specialization (r, t,
DECL_TI_ARGS (DECL_TEMPLATE_RESULT (r)),
error ("explicit instantiation of non-template %q#D", decl);
return;
}
- else if (VAR_P (decl))
+
+ bool var_templ = (DECL_TEMPLATE_INFO (decl)
+ && variable_template_p (DECL_TI_TEMPLATE (decl)));
+
+ if (VAR_P (decl) && !var_templ)
{
/* There is an asymmetry here in the way VAR_DECLs and
FUNCTION_DECLs are handled by grokdeclarator. In the case of
return;
}
}
- else if (TREE_CODE (decl) != FUNCTION_DECL)
+ else if (TREE_CODE (decl) != FUNCTION_DECL && !var_templ)
{
error ("explicit instantiation of %q#D", decl);
return;
tree ns;
tree init;
bool const_init = false;
+ bool enter_context = DECL_CLASS_SCOPE_P (d);
ns = decl_namespace_context (d);
push_nested_namespace (ns);
- push_nested_class (DECL_CONTEXT (d));
+ if (enter_context)
+ push_nested_class (DECL_CONTEXT (d));
init = tsubst_expr (DECL_INITIAL (code_pattern),
args,
tf_warning_or_error, NULL_TREE,
cp_finish_decl (d, init, /*init_const_expr_p=*/const_init,
/*asmspec_tree=*/NULL_TREE,
LOOKUP_ONLYCONVERTING);
- pop_nested_class ();
+ if (enter_context)
+ pop_nested_class ();
pop_nested_namespace (ns);
}
DECL_EXTERNAL (d) = 0;
/* Enter the scope of D so that access-checking works correctly. */
- push_nested_class (DECL_CONTEXT (d));
+ bool enter_context = DECL_CLASS_SCOPE_P (d);
+ if (enter_context)
+ push_nested_class (DECL_CONTEXT (d));
+
const_init = DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (code_pattern);
cp_finish_decl (d, init, const_init, NULL_TREE, 0);
- pop_nested_class ();
+
+ if (enter_context)
+ pop_nested_class ();
}
else if (TREE_CODE (d) == FUNCTION_DECL && DECL_DEFAULTED_FN (code_pattern))
synthesize_method (d);
return result;
}
+/* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
+
+tree
+finish_template_variable (tree var)
+{
+ return instantiate_template (TREE_OPERAND (var, 0), TREE_OPERAND (var, 1),
+ tf_error);
+}
+
/* Finish a call to a postfix increment or decrement or EXPR. (Which
is indicated by CODE, which should be POSTINCREMENT_EXPR or
POSTDECREMENT_EXPR.) */
a call to its wrapper. */
decl = build_cxx_call (wrap, 0, NULL, tf_warning_or_error);
}
+ else if (TREE_CODE (decl) == TEMPLATE_ID_EXPR
+ && variable_template_p (TREE_OPERAND (decl, 0)))
+ {
+ decl = finish_template_variable (decl);
+ }
else if (scope)
{
decl = (adjust_result_of_qualified_name_lookup
// PR c++/59638
// { dg-do compile { target c++1y } }
// { dg-options "" }
+// { dg-excess-errors "sorry" }
-void (*a)(auto); // { dg-error "template declaration" }
+void (*a)(auto); // { dg-error "" "" { xfail *-*-* } }
-void (*b)(auto) = 0; // { dg-error "template declaration" }
+void (*b)(auto) = 0; // { dg-error "" "" { xfail *-*-* } }
typedef void (*f)(auto); // { dg-error "template declaration" }
--- /dev/null
+// { dg-do run }
+// { dg-options "-std=c++1y" }
+
+template<int A, int B>
+ struct S1
+ {
+ static constexpr int a = A;
+ static constexpr int b = B;
+ };
+
+template<typename T>
+ constexpr int var = T::a + T::b;
+
+int main ()
+{
+ int v = var<S1<199, 23>>/2;
+ return !(
+ var<S1<11, 100>> == v
+ && var<S1<50, 120>> == var<S1<150, var<S1<10, 10>>>>
+ && var<S1<53, 23>> != 222
+ );
+}
--- /dev/null
+// { dg-do compile }
+// { dg-options "-std=c++1y" }
+
+// Template variables and static member variables of template classes are
+// often confused.
+
+template<typename T>
+ struct S1
+ {
+ static int n;
+ static int arr[];
+ };
+
+template<typename T>
+ constexpr int var = sizeof (T);
+
+template<typename T>
+ int S1<T>::n = sizeof (T);
+
+template<typename T>
+ int S1<T>::arr[sizeof (T)];
+
+template<>
+ int S1<int>::n = 8;
+
+template<>
+ int S1<int>::arr[8];
+
+int main ()
+{
+ S1<int> v1;
+ var<S1<int>>;
+ return 0;
+}
--- /dev/null
+// { dg-do run }
+// { dg-options "-std=c++1y" }
+
+template<typename T>
+ constexpr int var = sizeof (T);
+
+template<typename T>
+ struct S1
+ {
+ template<typename U>
+ static constexpr int a = sizeof (U) + sizeof (T);
+ };
+
+int main ()
+{
+ return !(
+ var<int> + var<char> == S1<int>::a<char>
+ );
+}
--- /dev/null
+// { dg-do run }
+// { dg-options "-std=c++1y" }
+
+template<typename T>
+ constexpr int var = sizeof (T);
+
+template<>
+ constexpr int var<int> = 100000;
+
+int main ()
+{
+ return !(
+ var<int> == 100000
+ && var<char> == sizeof(char)
+ );
+}
--- /dev/null
+// { dg-do run }
+// { dg-options "-std=c++1y" }
+
+template<int A, int B>
+ struct S1
+ {
+ static constexpr int a = A;
+ static constexpr int b = B;
+ };
+
+template<class T>
+ constexpr int var = T::a + T::b;
+
+template<template<int,int> class T, int A>
+ constexpr int var2 = var<T<A, A>> + A;
+
+int main ()
+{
+ return !(
+ var2<S1, 40> == 120
+ );
+}
static T i;
};
-template<> template <> int B<int>::i; // { dg-error "should be 1" }
+template<> template <> int B<int>::i; // { dg-error "template|should be 1" }
// PR c++/30659
-extern "C" template A<char> foo(); // { dg-error "forbids|static data|expected" }
+extern "C" template A<char> foo(); // { dg-error "forbids|static data|expected|template" }
};
bool A<int>::a = true; // ok
-template<> bool A<int>::b = false; // { dg-error "template header" }
+template<> bool A<int>::b = false; // { dg-error "template (header|variable)" }
// { dg-do assemble }
// Origin: Jason Merrill <jason@cygnus.com>
+// { dg-excess-errors "sorry" }
-template <class T> T t; // { dg-error "" } template declaration of t
+template <class T> T t; // template declaration of t
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