[es7] Implement async functions parsing

src/runtime/runtime-function.cc

 // Copyright 2014 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/accessors.h"
 #include "src/arguments.h"
 #include "src/compiler.h"
 #include "src/deoptimizer.h"
@@ skipping 87 matching lines @@
 RUNTIME_FUNCTION(Runtime_FunctionGetSourceCode) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
 
   CONVERT_ARG_HANDLE_CHECKED(JSFunction, f, 0);
   Handle<SharedFunctionInfo> shared(f->shared());
   return *shared->GetSourceCode();
 }
 
 
+RUNTIME_FUNCTION(Runtime_FunctionIsAsync) {
+  SealHandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_CHECKED(JSFunction, f, 0);
+  return isolate->heap()->ToBoolean(f->shared()->is_async());
+}
+
+
 RUNTIME_FUNCTION(Runtime_FunctionGetScriptSourcePosition) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
 
   CONVERT_ARG_CHECKED(JSFunction, fun, 0);
   int pos = fun->shared()->start_position();
   return Smi::FromInt(pos);
 }
 
 
@@ skipping 480 matching lines @@
 
 
 RUNTIME_FUNCTION(Runtime_ThrowStrongModeTooFewArguments) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 0);
   THROW_NEW_ERROR_RETURN_FAILURE(isolate,
                                  NewTypeError(MessageTemplate::kStrongArity));
 }
 }  // namespace internal
 }  // namespace v8