[builtins] implement JSBuiltinReducer for ArrayIteratorNext()

src/isolate-inl.h

 // 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.
 
 #ifndef V8_ISOLATE_INL_H_
 #define V8_ISOLATE_INL_H_
 
 #include "src/isolate.h"
 #include "src/objects-inl.h"
 
@@ skipping 125 matching lines @@
 bool Isolate::IsHasInstanceLookupChainIntact() {
   PropertyCell* has_instance_cell = heap()->has_instance_protector();
   return has_instance_cell->value() == Smi::FromInt(kArrayProtectorValid);
 }
 
 bool Isolate::IsStringLengthOverflowIntact() {
   PropertyCell* has_instance_cell = heap()->string_length_protector();
   return has_instance_cell->value() == Smi::FromInt(kArrayProtectorValid);
 }
 
+bool Isolate::CanInlineArrayIterator() {

[Camillo Bruni, 2016/11/09 12:03:49]

nit: Could you rename this function to be more consistent with the rest?
IsArrayIteratorLookupChainIntact() maybe?

[caitp, 2016/11/09 17:40:16]

I'm not sure what a good name for this is, but "LookupChainIntact" seems to be
unrelated to what it's actually tracking. "IsArrayIteratedObjectMapIntact"
maybe?

+  Cell* array_iterator_cell = heap()->array_iterator_protector();
+  return array_iterator_cell->value() == Smi::FromInt(kArrayProtectorValid);
+}
+
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ISOLATE_INL_H_