tree
build_capture_proxy (tree member)
{
tree var, object, fn, closure, name, lam, type;
if (PACK_EXPANSION_P (member))
member = PACK_EXPANSION_PATTERN (member);
closure = DECL_CONTEXT (member);
fn = lambda_function (closure);
lam = CLASSTYPE_LAMBDA_EXPR (closure);
/* The proxy variable forwards to the capture field. */
object = build_fold_indirect_ref (DECL_ARGUMENTS (fn));
object = finish_non_static_data_member (member, object, NULL_TREE);
if (REFERENCE_REF_P (object))
object = TREE_OPERAND (object, 0);
/* Remove the __ inserted by add_capture. */
if (DECL_NORMAL_CAPTURE_P (member))
name = get_identifier (IDENTIFIER_POINTER (DECL_NAME (member)) + 2);
else
name = DECL_NAME (member);
type = lambda_proxy_type (object);
if (DECL_VLA_CAPTURE_P (member))
{
/* Rebuild the VLA type from the pointer and maxindex. */
tree field = next_initializable_field (TYPE_FIELDS (type));
tree ptr = build_simple_component_ref (object, field);
field = next_initializable_field (DECL_CHAIN (field));
tree max = build_simple_component_ref (object, field);
type = build_cplus_array_type (TREE_TYPE (TREE_TYPE (ptr)),
build_index_type (max));
type = build_reference_type (type);
REFERENCE_VLA_OK (type) = true;
object = convert (type, ptr);
}
var = build_decl (input_location, VAR_DECL, name, type);
SET_DECL_VALUE_EXPR (var, object);
DECL_HAS_VALUE_EXPR_P (var) = 1;
DECL_ARTIFICIAL (var) = 1;
TREE_USED (var) = 1;
DECL_CONTEXT (var) = fn;
if (name == this_identifier)
{
gcc_assert (LAMBDA_EXPR_THIS_CAPTURE (lam) == member);
LAMBDA_EXPR_THIS_CAPTURE (lam) = var;
}
if (fn == current_function_decl)
insert_capture_proxy (var);
else
vec_safe_push (LAMBDA_EXPR_PENDING_PROXIES (lam), var);
return var;
}
tree
build_lambda_object (tree lambda_expr)
{
/* Build aggregate constructor call.
- cp_parser_braced_list
- cp_parser_functional_cast */
vec<constructor_elt, va_gc> *elts = NULL;
tree node, expr, type;
location_t saved_loc;
if (processing_template_decl)
return lambda_expr;
/* Make sure any error messages refer to the lambda-introducer. */
saved_loc = input_location;
input_location = LAMBDA_EXPR_LOCATION (lambda_expr);
for (node = LAMBDA_EXPR_CAPTURE_LIST (lambda_expr);
node;
node = TREE_CHAIN (node))
{
tree field = TREE_PURPOSE (node);
tree val = TREE_VALUE (node);
if (field == error_mark_node)
{
expr = error_mark_node;
goto out;
}
if (DECL_P (val))
mark_used (val);
/* Mere mortals can't copy arrays with aggregate initialization, so
do some magic to make it work here. */
if (TREE_CODE (TREE_TYPE (field)) == ARRAY_TYPE)
val = build_array_copy (val);
else if (DECL_NORMAL_CAPTURE_P (field)
&& !DECL_VLA_CAPTURE_P (field)
&& TREE_CODE (TREE_TYPE (field)) != REFERENCE_TYPE)
{
/* "the entities that are captured by copy are used to
direct-initialize each corresponding non-static data
member of the resulting closure object."
There's normally no way to express direct-initialization
from an element of a CONSTRUCTOR, so we build up a special
TARGET_EXPR to bypass the usual copy-initialization. */
val = force_rvalue (val, tf_warning_or_error);
if (TREE_CODE (val) == TARGET_EXPR)
TARGET_EXPR_DIRECT_INIT_P (val) = true;
}
CONSTRUCTOR_APPEND_ELT (elts, DECL_NAME (field), val);
}
expr = build_constructor (init_list_type_node, elts);
CONSTRUCTOR_IS_DIRECT_INIT (expr) = 1;
/* N2927: "[The closure] class type is not an aggregate."
But we briefly treat it as an aggregate to make this simpler. */
type = LAMBDA_EXPR_CLOSURE (lambda_expr);
CLASSTYPE_NON_AGGREGATE (type) = 0;
expr = finish_compound_literal (type, expr, tf_warning_or_error);
CLASSTYPE_NON_AGGREGATE (type) = 1;
out:
input_location = saved_loc;
return expr;
}
tree
add_capture (tree lambda, tree id, tree orig_init, bool by_reference_p,
bool explicit_init_p)
{
char *buf;
tree type, member, name;
bool vla = false;
bool variadic = false;
tree initializer = orig_init;
if (PACK_EXPANSION_P (initializer))
{
initializer = PACK_EXPANSION_PATTERN (initializer);
variadic = true;
}
if (TREE_CODE (initializer) == TREE_LIST)
initializer = build_x_compound_expr_from_list (initializer, ELK_INIT,
tf_warning_or_error);
type = TREE_TYPE (initializer);
if (type == error_mark_node)
return error_mark_node;
if (array_of_runtime_bound_p (type))
{
vla = true;
if (!by_reference_p)
error ("array of runtime bound cannot be captured by copy, "
"only by reference");
/* For a VLA, we capture the address of the first element and the
maximum index, and then reconstruct the VLA for the proxy. */
tree elt = cp_build_array_ref (input_location, initializer,
integer_zero_node, tf_warning_or_error);
initializer = build_constructor_va (init_list_type_node, 2,
NULL_TREE, build_address (elt),
NULL_TREE, array_type_nelts (type));
type = vla_capture_type (type);
}
else if (!dependent_type_p (type)
&& variably_modified_type_p (type, NULL_TREE))
{
error ("capture of variable-size type %qT that is not an N3639 array "
"of runtime bound", type);
if (TREE_CODE (type) == ARRAY_TYPE
&& variably_modified_type_p (TREE_TYPE (type), NULL_TREE))
inform (input_location, "because the array element type %qT has "
"variable size", TREE_TYPE (type));
type = error_mark_node;
}
else
{
type = lambda_capture_field_type (initializer, explicit_init_p);
if (by_reference_p)
{
type = build_reference_type (type);
if (!dependent_type_p (type) && !real_lvalue_p (initializer))
error ("cannot capture %qE by reference", initializer);
}
else
{
/* Capture by copy requires a complete type. */
type = complete_type (type);
if (!dependent_type_p (type) && !COMPLETE_TYPE_P (type))
{
error ("capture by copy of incomplete type %qT", type);
cxx_incomplete_type_inform (type);
return error_mark_node;
}
}
}
/* Add __ to the beginning of the field name so that user code
won't find the field with name lookup. We can't just leave the name
unset because template instantiation uses the name to find
instantiated fields. */
buf = (char *) alloca (IDENTIFIER_LENGTH (id) + 3);
buf[1] = buf[0] = '_';
memcpy (buf + 2, IDENTIFIER_POINTER (id),
IDENTIFIER_LENGTH (id) + 1);
name = get_identifier (buf);
/* If TREE_TYPE isn't set, we're still in the introducer, so check
for duplicates. */
if (!LAMBDA_EXPR_CLOSURE (lambda))
{
if (IDENTIFIER_MARKED (name))
{
pedwarn (input_location, 0,
"already captured %qD in lambda expression", id);
return NULL_TREE;
}
IDENTIFIER_MARKED (name) = true;
}
if (variadic)
type = make_pack_expansion (type);
/* Make member variable. */
member = build_decl (input_location, FIELD_DECL, name, type);
DECL_VLA_CAPTURE_P (member) = vla;
if (!explicit_init_p)
/* Normal captures are invisible to name lookup but uses are replaced
with references to the capture field; we implement this by only
really making them invisible in unevaluated context; see
qualify_lookup. For now, let's make explicitly initialized captures
always visible. */
DECL_NORMAL_CAPTURE_P (member) = true;
if (id == this_identifier)
LAMBDA_EXPR_THIS_CAPTURE (lambda) = member;
/* Add it to the appropriate closure class if we've started it. */
if (current_class_type
&& current_class_type == LAMBDA_EXPR_CLOSURE (lambda))
finish_member_declaration (member);
tree listmem = member;
if (variadic)
{
listmem = make_pack_expansion (member);
initializer = orig_init;
}
LAMBDA_EXPR_CAPTURE_LIST (lambda)
= tree_cons (listmem, initializer, LAMBDA_EXPR_CAPTURE_LIST (lambda));
if (LAMBDA_EXPR_CLOSURE (lambda))
return build_capture_proxy (member);
/* For explicit captures we haven't started the function yet, so we wait
and build the proxy from cp_parser_lambda_body. */
return NULL_TREE;
}
