Optimize testing for an index's existence in packed Arrays

src/runtime/runtime.h

 // Copyright 2012 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_RUNTIME_RUNTIME_H_
 #define V8_RUNTIME_RUNTIME_H_
 
 #include "src/allocation.h"
 #include "src/objects.h"
 #include "src/zone.h"
@@ skipping 714 matching lines @@
   F(ConstructDouble, 2, 1)                \
   F(DoubleHi, 1, 1)                       \
   F(DoubleLo, 1, 1)                       \
   F(MathSqrtRT, 1, 1)                     \
   F(MathLogRT, 1, 1)                      \
   /* ES6 Collections */                   \
   F(MapGet, 2, 1)                         \
   F(MapGetSize, 1, 1)                     \
   F(MapHas, 2, 1)                         \
   F(SetGetSize, 1, 1)                     \
-  F(SetHas, 2, 1)
+  F(SetHas, 2, 1)                         \
+  /* Arrays */                            \
+  F(HasFastPackedElements, 1, 1)
 
 
 //---------------------------------------------------------------------------
 // Runtime provides access to all C++ runtime functions.
 
 class RuntimeState {
  public:
   unibrow::Mapping<unibrow::ToUppercase, 128>* to_upper_mapping() {
     return &to_upper_mapping_;
   }
@@ skipping 145 matching lines @@
 class AllocateTargetSpace : public BitField<AllocationSpace, 1, 3> {};
 
 class DeclareGlobalsEvalFlag : public BitField<bool, 0, 1> {};
 class DeclareGlobalsNativeFlag : public BitField<bool, 1, 1> {};
 class DeclareGlobalsStrictMode : public BitField<StrictMode, 2, 1> {};
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_RUNTIME_RUNTIME_H_