V8 support for cached accessors.

src/lookup.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/lookup.h"
 
 #include "src/bootstrapper.h"
 #include "src/deoptimizer.h"
 #include "src/elements.h"
 #include "src/field-type.h"
@@ skipping 824 matching lines @@
   if (access_check_info) {
     Object* interceptor = IsElement() ? access_check_info->indexed_interceptor()
                                       : access_check_info->named_interceptor();
     if (interceptor) {
       return handle(InterceptorInfo::cast(interceptor), isolate_);
     }
   }
   return Handle<InterceptorInfo>();
 }
 
+bool LookupIterator::TryLookupCachedProperty() {
+  return state() == LookupIterator::ACCESSOR &&
+         GetAccessors()->IsAccessorPair() && LookupCachedProperty();
+}
+
+bool LookupIterator::LookupCachedProperty() {
+  DCHECK_EQ(state(), LookupIterator::ACCESSOR);
+  DCHECK(GetAccessors()->IsAccessorPair());
+
+  Handle<Object> getter(Handle<AccessorPair>::cast(GetAccessors())->getter(),

[Toon Verwaest, 2016/11/04 10:19:52]

AccessorPair::cast(*GetAccessors())->getter(), isolate()) might fit on one line
:)

[vogelheim, 2016/11/04 12:34:42]

Didn't fit :)
Since I need two lines anyway, I gave the pointer a name to make a tiny bit
prettier.

+                        isolate());
+  MaybeHandle<Name> maybe_name =
+      FunctionTemplateInfo::TryGetCachedPropertyName(isolate(), getter);
+  if (maybe_name.is_null()) return false;
+
+  // We have found a cached property! Modify the iterator accordingly.
+  name_ = maybe_name.ToHandleChecked();
+  Restart();
+  CHECK_EQ(state(), LookupIterator::DATA);
+  return true;
+}
+
 }  // namespace internal
 }  // namespace v8