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

src/code-stubs.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_CODE_STUBS_H_
 #define V8_CODE_STUBS_H_
 
 #include "src/allocation.h"
 #include "src/assembler.h"
 #include "src/codegen.h"
@@ skipping 1728 matching lines @@
 
 
 class CEntryStub : public PlatformCodeStub {
  public:
   CEntryStub(Isolate* isolate, int result_size,
              SaveFPRegsMode save_doubles = kDontSaveFPRegs,
              ArgvMode argv_mode = kArgvOnStack)
       : PlatformCodeStub(isolate) {
     minor_key_ = SaveDoublesBits::encode(save_doubles == kSaveFPRegs) |
                  ArgvMode::encode(argv_mode == kArgvInRegister);
-    DCHECK(result_size == 1 || result_size == 2);
-#if _WIN64 || V8_TARGET_ARCH_PPC
+    DCHECK(result_size == 1 || result_size == 2 || result_size == 3);
     minor_key_ = ResultSizeBits::update(minor_key_, result_size);
-#endif  // _WIN64
   }
 
   // The version of this stub that doesn't save doubles is generated ahead of
   // time, so it's OK to call it from other stubs that can't cope with GC during
   // their code generation.  On machines that always have gp registers (x64) we
   // can generate both variants ahead of time.
   static void GenerateAheadOfTime(Isolate* isolate);
 
  private:
   bool save_doubles() const { return SaveDoublesBits::decode(minor_key_); }
   bool argv_in_register() const { return ArgvMode::decode(minor_key_); }
-#if _WIN64 || V8_TARGET_ARCH_PPC
   int result_size() const { return ResultSizeBits::decode(minor_key_); }
-#endif  // _WIN64
 
   bool NeedsImmovableCode() override;
 
   class SaveDoublesBits : public BitField<bool, 0, 1> {};
   class ArgvMode : public BitField<bool, 1, 1> {};
   class ResultSizeBits : public BitField<int, 2, 3> {};
 
   DEFINE_NULL_CALL_INTERFACE_DESCRIPTOR();
   DEFINE_PLATFORM_CODE_STUB(CEntry, PlatformCodeStub);
 };
@@ skipping 1197 matching lines @@
 #undef DEFINE_HYDROGEN_CODE_STUB
 #undef DEFINE_CODE_STUB
 #undef DEFINE_CODE_STUB_BASE
 
 extern Representation RepresentationFromType(Type* type);
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_CODE_STUBS_H_