+/* Return a suitable initializer for value-initializing an object of type
+ TYPE, as described in [dcl.init]. If HAVE_CTOR is true, the initializer
+ for an enclosing object is already calling the constructor for this
+ object. */
+
+static tree
+build_value_init_1 (tree type, bool have_ctor)
+{
+ /* [dcl.init]
+
+ To value-initialize an object of type T means:
+
+ - if T is a class type (clause 9) with a user-provided constructor
+ (12.1), then the default constructor for T is called (and the
+ initialization is ill-formed if T has no accessible default
+ constructor);
+
+ - if T is a non-union class type without a user-provided constructor,
+ then every non-static data member and base-class component of T is
+ value-initialized;92)
+
+ - if T is an array type, then each element is value-initialized;
+
+ - otherwise, the object is zero-initialized.
+
+ A program that calls for default-initialization or
+ value-initialization of an entity of reference type is ill-formed.
+
+ 92) Value-initialization for such a class object may be implemented by
+ zero-initializing the object and then calling the default
+ constructor. */
+
+ if (CLASS_TYPE_P (type))
+ {
+ if (type_has_user_provided_constructor (type) && !have_ctor)
+ return build_aggr_init_expr
+ (type,
+ build_special_member_call (NULL_TREE, complete_ctor_identifier,
+ NULL_TREE, type, LOOKUP_NORMAL,
+ tf_warning_or_error));
+ else if (TREE_CODE (type) != UNION_TYPE)
+ {
+ tree field, init;
+ VEC(constructor_elt,gc) *v = NULL;
+ bool call_ctor = !have_ctor && TYPE_NEEDS_CONSTRUCTING (type);
+
+ /* Iterate over the fields, building initializations. */
+ for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
+ {
+ tree ftype, value;
+
+ if (TREE_CODE (field) != FIELD_DECL)
+ continue;
+
+ ftype = TREE_TYPE (field);
+
+ if (TREE_CODE (ftype) == REFERENCE_TYPE)
+ error ("value-initialization of reference");
+
+ /* We could skip vfields and fields of types with
+ user-defined constructors, but I think that won't improve
+ performance at all; it should be simpler in general just
+ to zero out the entire object than try to only zero the
+ bits that actually need it. */
+
+ /* Note that for class types there will be FIELD_DECLs
+ corresponding to base classes as well. Thus, iterating
+ over TYPE_FIELDs will result in correct initialization of
+ all of the subobjects. */
+ value = build_value_init_1 (ftype, have_ctor || call_ctor);
+
+ if (value)
+ CONSTRUCTOR_APPEND_ELT(v, field, value);
+ }
+
+ /* Build a constructor to contain the zero- initializations. */
+ init = build_constructor (type, v);
+ if (call_ctor)
+ {
+ /* This is a class that needs constructing, but doesn't have
+ a user-defined constructor. So we need to zero-initialize
+ the object and then call the implicitly defined ctor.
+ Implement this by sticking the zero-initialization inside
+ the TARGET_EXPR for the constructor call;
+ cp_gimplify_init_expr will know how to handle it. */
+ tree ctor = build_special_member_call
+ (NULL_TREE, complete_ctor_identifier,
+ NULL_TREE, type, LOOKUP_NORMAL, tf_warning_or_error);
+
+ ctor = build_cplus_new (type, ctor);
+ init = build2 (INIT_EXPR, void_type_node,
+ TARGET_EXPR_SLOT (ctor), init);
+ init = build2 (COMPOUND_EXPR, void_type_node, init,
+ TARGET_EXPR_INITIAL (ctor));
+ TARGET_EXPR_INITIAL (ctor) = init;
+ return ctor;
+ }
+ return init;
+ }
+ }
+ else if (TREE_CODE (type) == ARRAY_TYPE)
+ {
+ VEC(constructor_elt,gc) *v = NULL;
+
+ /* Iterate over the array elements, building initializations. */
+ tree max_index = array_type_nelts (type);
+
+ /* If we have an error_mark here, we should just return error mark
+ as we don't know the size of the array yet. */
+ if (max_index == error_mark_node)
+ return error_mark_node;
+ gcc_assert (TREE_CODE (max_index) == INTEGER_CST);
+
+ /* A zero-sized array, which is accepted as an extension, will
+ have an upper bound of -1. */
+ if (!tree_int_cst_equal (max_index, integer_minus_one_node))
+ {
+ constructor_elt *ce;
+
+ v = VEC_alloc (constructor_elt, gc, 1);
+ ce = VEC_quick_push (constructor_elt, v, NULL);
+
+ /* If this is a one element array, we just use a regular init. */
+ if (tree_int_cst_equal (size_zero_node, max_index))
+ ce->index = size_zero_node;
+ else
+ ce->index = build2 (RANGE_EXPR, sizetype, size_zero_node,
+ max_index);
+
+ ce->value = build_value_init_1 (TREE_TYPE (type), have_ctor);
+ }
+
+ /* Build a constructor to contain the initializations. */
+ return build_constructor (type, v);
+ }
+
+ return build_zero_init (type, NULL_TREE, /*static_storage_p=*/false);
+}
+
+/* Return a suitable initializer for value-initializing an object of type
+ TYPE, as described in [dcl.init]. */
+
+tree
+build_value_init (tree type)
+{
+ return build_value_init_1 (type, false);
+}
+
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