[Interpreter] Add ForInPrepare runtime function which returns a ObjectTriple.

src/assembler.h

 // Copyright (c) 1994-2006 Sun Microsystems Inc.
 // All Rights Reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 // - Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 //
@@ skipping 796 matching lines @@
 // An ExternalReference represents a C++ address used in the generated
 // code. All references to C++ functions and variables must be encapsulated in
 // an ExternalReference instance. This is done in order to track the origin of
 // all external references in the code so that they can be bound to the correct
 // addresses when deserializing a heap.
 class ExternalReference BASE_EMBEDDED {
  public:
   // Used in the simulator to support different native api calls.
   enum Type {
     // Builtin call.
-    // Object* f(v8::internal::Arguments).
+    // Object* f(v8::internal::Arguments) or
+    // ObjectPair f(v8::internal::Arguments).
     BUILTIN_CALL,  // default
 
+    // Builtin call that returns .
+    // ObjectTriple f(v8::internal::Arguments).
+    BUILTIN_CALL_TRIPLE,
+
     // Builtin that takes float arguments and returns an int.
     // int f(double, double).
     BUILTIN_COMPARE_CALL,
 
     // Builtin call that returns floating point.
     // double f(double, double).
     BUILTIN_FP_FP_CALL,
 
     // Builtin call that returns floating point.
     // double f(double).
@@ skipping 444 matching lines @@
     std::vector<ConstantPoolEntry> shared_entries;
   };
 
   Label emitted_label_;  // Records pc_offset of emitted pool
   PerTypeEntryInfo info_[ConstantPoolEntry::NUMBER_OF_TYPES];
 };
 
 }  // namespace internal
 }  // namespace v8
 #endif  // V8_ASSEMBLER_H_