Move ArrayBuffer.prototype.slice implementation to C++

src/objects.cc

 // Copyright 2015 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/objects.h"
 
 #include <cmath>
 #include <iomanip>
 #include <memory>
 #include <sstream>
@@ skipping 2308 matching lines @@
   } else {
     if (!constructor->IsConstructor()) {
       THROW_NEW_ERROR(isolate,
           NewTypeError(MessageTemplate::kSpeciesNotConstructor),
           Object);
     }
     return constructor;
   }
 }
 
+// ES6 section 7.3.20 SpeciesConstructor ( O, defaultConstructor )
+MUST_USE_RESULT MaybeHandle<Object> Object::SpeciesConstructor(
+    Isolate* isolate, Handle<JSReceiver> recv,
+    Handle<JSFunction> default_ctor) {
+  Handle<Object> ctor_obj;
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate, ctor_obj,
+      JSObject::GetProperty(recv, isolate->factory()->constructor_string()),
+      Object);
+
+  if (ctor_obj->IsUndefined(isolate)) return default_ctor;
+
+  if (!ctor_obj->IsJSReceiver()) {
+    THROW_NEW_ERROR(isolate,
+                    NewTypeError(MessageTemplate::kConstructorNotReceiver),
+                    Object);
+  }
+
+  Handle<JSReceiver> ctor = Handle<JSReceiver>::cast(ctor_obj);
+
+  Handle<Object> species;
+  ASSIGN_RETURN_ON_EXCEPTION(
+      isolate, species,
+      JSObject::GetProperty(ctor, isolate->factory()->species_symbol()),
+      Object);
+
+  if (species->IsNullOrUndefined(isolate)) {
+    return default_ctor;
+  }
+
+  if (species->IsConstructor()) return species;
+
+  THROW_NEW_ERROR(
+      isolate, NewTypeError(MessageTemplate::kSpeciesNotConstructor), Object);
+}
+
 bool Object::IterationHasObservableEffects() {
   // Check that this object is an array.
   if (!IsJSArray()) return true;
   JSArray* spread_array = JSArray::cast(this);
   Isolate* isolate = spread_array->GetIsolate();
 
   // Check that we have the original ArrayPrototype.
   JSObject* array_proto = JSObject::cast(spread_array->map()->prototype());
   if (!isolate->is_initial_array_prototype(array_proto)) return true;
 
@@ skipping 17723 matching lines @@
       // depend on this.
       return DICTIONARY_ELEMENTS;
     }
     DCHECK_LE(kind, LAST_ELEMENTS_KIND);
     return kind;
   }
 }
 
 }  // namespace internal
 }  // namespace v8