Turn Array.isArray into a Turbofan stub

src/runtime/runtime-array.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/arguments.h"
 #include "src/code-stubs.h"
 #include "src/conversions-inl.h"
 #include "src/elements.h"
@@ skipping 437 matching lines @@
       return isolate->heap()->true_value();
     }
     if (!current->HasDictionaryElements()) continue;
     if (current->element_dictionary()->HasComplexElements()) {
       return isolate->heap()->true_value();
     }
   }
   return isolate->heap()->false_value();
 }
 
+// ES6 22.1.2.2 Array.isArray
+RUNTIME_FUNCTION(Runtime_ArrayIsArray) {
+  HandleScope shs(isolate);
+  DCHECK(args.length() == 1);
+  CONVERT_ARG_HANDLE_CHECKED(Object, object, 0);
+  Maybe<bool> result = Object::IsArray(object);
+  MAYBE_RETURN(result, isolate->heap()->exception());
+  return isolate->heap()->ToBoolean(result.FromJust());
+}
 
 RUNTIME_FUNCTION(Runtime_IsArray) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_CHECKED(Object, obj, 0);
   return isolate->heap()->ToBoolean(obj->IsJSArray());
 }
 
-
 RUNTIME_FUNCTION(Runtime_HasCachedArrayIndex) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 1);
   return isolate->heap()->false_value();
 }
 
 
 RUNTIME_FUNCTION(Runtime_GetCachedArrayIndex) {
   // This can never be reached, because Runtime_HasCachedArrayIndex always
   // returns false.
   UNIMPLEMENTED();
   return nullptr;
 }
 
 
 RUNTIME_FUNCTION(Runtime_ArraySpeciesConstructor) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_ARG_HANDLE_CHECKED(Object, original_array, 0);
   Handle<Object> constructor;
   ASSIGN_RETURN_FAILURE_ON_EXCEPTION(
       isolate, constructor,
       Object::ArraySpeciesConstructor(isolate, original_array));
   return *constructor;
 }
 
 }  // namespace internal
 }  // namespace v8