tree
add_default_capture (tree lambda_stack, tree id, tree initializer)
{
bool this_capture_p = (id == this_identifier);
tree var = NULL_TREE;
tree saved_class_type = current_class_type;
tree node;
for (node = lambda_stack;
node;
node = TREE_CHAIN (node))
{
tree lambda = TREE_VALUE (node);
current_class_type = LAMBDA_EXPR_CLOSURE (lambda);
if (DECL_PACK_P (initializer))
initializer = make_pack_expansion (initializer);
var = add_capture (lambda,
id,
initializer,
/*by_reference_p=*/
(!this_capture_p
&& (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda)
== CPLD_REFERENCE)),
/*explicit_init_p=*/false);
initializer = convert_from_reference (var);
}
current_class_type = saved_class_type;
return var;
}
void
cxx_print_lambda_node (FILE *file, tree node, int indent)
{
if (LAMBDA_EXPR_MUTABLE_P (node))
fprintf (file, " /mutable");
fprintf (file, " default_capture_mode=[");
switch (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (node))
{
case CPLD_NONE:
fprintf (file, "NONE");
break;
case CPLD_COPY:
fprintf (file, "COPY");
break;
case CPLD_REFERENCE:
fprintf (file, "CPLD_REFERENCE");
break;
default:
fprintf (file, "??");
break;
}
fprintf (file, "] ");
print_node (file, "capture_list", LAMBDA_EXPR_CAPTURE_LIST (node), indent + 4);
print_node (file, "this_capture", LAMBDA_EXPR_THIS_CAPTURE (node), indent + 4);
print_node (file, "return_type", LAMBDA_EXPR_RETURN_TYPE (node), indent + 4);
print_node (file, "closure", LAMBDA_EXPR_CLOSURE (node), indent + 4);
}
tree
build_lambda_expr (void)
{
tree lambda = make_node (LAMBDA_EXPR);
LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda) = CPLD_NONE;
LAMBDA_EXPR_CAPTURE_LIST (lambda) = NULL_TREE;
LAMBDA_EXPR_THIS_CAPTURE (lambda) = NULL_TREE;
LAMBDA_EXPR_PENDING_PROXIES (lambda) = NULL;
LAMBDA_EXPR_RETURN_TYPE (lambda) = NULL_TREE;
LAMBDA_EXPR_MUTABLE_P (lambda) = false;
return lambda;
}
tree
lambda_expr_this_capture (tree lambda, bool add_capture_p)
{
tree result;
tree this_capture = LAMBDA_EXPR_THIS_CAPTURE (lambda);
/* In unevaluated context this isn't an odr-use, so don't capture. */
if (cp_unevaluated_operand)
add_capture_p = false;
/* Try to default capture 'this' if we can. */
if (!this_capture
&& (!add_capture_p
|| LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (lambda) != CPLD_NONE))
{
tree lambda_stack = NULL_TREE;
tree init = NULL_TREE;
/* If we are in a lambda function, we can move out until we hit:
1. a non-lambda function or NSDMI,
2. a lambda function capturing 'this', or
3. a non-default capturing lambda function. */
for (tree tlambda = lambda; ;)
{
lambda_stack = tree_cons (NULL_TREE,
tlambda,
lambda_stack);
if (LAMBDA_EXPR_EXTRA_SCOPE (tlambda)
&& TREE_CODE (LAMBDA_EXPR_EXTRA_SCOPE (tlambda)) == FIELD_DECL)
{
/* In an NSDMI, we don't have a function to look up the decl in,
but the fake 'this' pointer that we're using for parsing is
in scope_chain. */
init = scope_chain->x_current_class_ptr;
gcc_checking_assert
(init && (TREE_TYPE (TREE_TYPE (init))
== current_nonlambda_class_type ()));
break;
}
tree closure_decl = TYPE_NAME (LAMBDA_EXPR_CLOSURE (tlambda));
tree containing_function = decl_function_context (closure_decl);
if (containing_function == NULL_TREE)
/* We ran out of scopes; there's no 'this' to capture. */
break;
if (!LAMBDA_FUNCTION_P (containing_function))
{
/* We found a non-lambda function. */
if (DECL_NONSTATIC_MEMBER_FUNCTION_P (containing_function))
/* First parameter is 'this'. */
init = DECL_ARGUMENTS (containing_function);
break;
}
tlambda
= CLASSTYPE_LAMBDA_EXPR (DECL_CONTEXT (containing_function));
if (LAMBDA_EXPR_THIS_CAPTURE (tlambda))
{
/* An outer lambda has already captured 'this'. */
init = LAMBDA_EXPR_THIS_CAPTURE (tlambda);
break;
}
if (LAMBDA_EXPR_DEFAULT_CAPTURE_MODE (tlambda) == CPLD_NONE)
/* An outer lambda won't let us capture 'this'. */
break;
}
if (init)
{
if (add_capture_p)
this_capture = add_default_capture (lambda_stack,
/*id=*/this_identifier,
init);
else
this_capture = init;
}
}
if (cp_unevaluated_operand)
result = this_capture;
else if (!this_capture)
{
if (add_capture_p)
{
error ("%<this%> was not captured for this lambda function");
result = error_mark_node;
}
else
result = NULL_TREE;
}
else
{
/* To make sure that current_class_ref is for the lambda. */
gcc_assert (TYPE_MAIN_VARIANT (TREE_TYPE (current_class_ref))
== LAMBDA_EXPR_CLOSURE (lambda));
result = this_capture;
/* If 'this' is captured, each use of 'this' is transformed into an
access to the corresponding unnamed data member of the closure
type cast (_expr.cast_ 5.4) to the type of 'this'. [ The cast
ensures that the transformed expression is an rvalue. ] */
result = rvalue (result);
}
return result;
}
