New hydrogen instruction to reduce cost of growing an array on keyed stores.

src/interface-descriptors.h

 // 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.
 
 #ifndef V8_CALL_INTERFACE_DESCRIPTOR_H_
 #define V8_CALL_INTERFACE_DESCRIPTOR_H_
 
 #include "src/assembler.h"
 #include "src/macro-assembler.h"
 
@@ skipping 527 matching lines @@
 class ContextOnlyDescriptor : public CallInterfaceDescriptor {
  public:
   DECLARE_DESCRIPTOR(ContextOnlyDescriptor, CallInterfaceDescriptor)
 };
 
 
 class GrowArrayElementsDescriptor : public CallInterfaceDescriptor {
  public:
   DECLARE_DESCRIPTOR(GrowArrayElementsDescriptor, CallInterfaceDescriptor)
 
-  enum RegisterInfo { kObjectIndex, kKeyIndex, kCapacityIndex };
+  enum RegisterInfo { kObjectIndex, kKeyIndex };
   static const Register ObjectRegister();
   static const Register KeyRegister();
-  static const Register CapacityRegister();
 };
 
 #undef DECLARE_DESCRIPTOR
 
 
 // We define the association between CallDescriptors::Key and the specialized
 // descriptor here to reduce boilerplate and mistakes.
 #define DEF_KEY(name) \
   CallDescriptors::Key name##Descriptor::key() { return CallDescriptors::name; }
 INTERFACE_DESCRIPTOR_LIST(DEF_KEY)
 #undef DEF_KEY
 }
 }  // namespace v8::internal
 
 
 #if V8_TARGET_ARCH_ARM64
 #include "src/arm64/interface-descriptors-arm64.h"
 #elif V8_TARGET_ARCH_ARM
 #include "src/arm/interface-descriptors-arm.h"
 #endif
 
 #endif  // V8_CALL_INTERFACE_DESCRIPTOR_H_