[builtins] introduce AsyncBuiltinsAssembler for ES2016 features and beyond

src/builtins/builtins-async.h

+// Copyright 2016 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_BUILTINS_BUILTINS_ASYNC_H_
+#define V8_BUILTINS_BUILTINS_ASYNC_H_
+
+#include "src/builtins/builtins-promise.h"
+
+namespace v8 {
+namespace internal {
+
+class AsyncBuiltinsAssembler : public PromiseBuiltinsAssembler {
+ public:
+  explicit AsyncBuiltinsAssembler(CodeAssemblerState* state)
+      : PromiseBuiltinsAssembler(state) {}
+
+ protected:
+  typedef std::function<Node*(Node*)> NodeGenerator1;
+
+  // Perform steps to resume generator after `value` is resolved.
+  // `on_reject_context_index` is an index into the Native Context, which should
+  // point to a SharedFunctioninfo instance used to create the closure. The
+  // value following the reject index should be a similar value for the resolve
+  // closure. Returns the Promise-wrapped `value`.
+  Node* Await(Node* context, Node* generator, Node* value, Node* outer_promise,
+              const NodeGenerator1& create_closure_context,
+              int on_resolve_context_index, int on_reject_context_index,
+              bool is_catchable);
+};
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_BUILTINS_BUILTINS_ASYNC_H_