[Interpreter] Add support for JS runtime calls.

src/interpreter/bytecode-array-iterator.cc

 // 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.
 
 #include "src/interpreter/bytecode-array-iterator.h"
 
 #include "src/objects-inl.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 58 matching lines @@
   OperandSize size =
       Bytecodes::GetOperandSize(current_bytecode(), operand_index);
   OperandType type =
       (size == OperandSize::kByte) ? OperandType::kIdx8 : OperandType::kIdx16;
   uint32_t operand = GetRawOperand(operand_index, type);
   return static_cast<int>(operand);
 }
 
 
 Register BytecodeArrayIterator::GetRegisterOperand(int operand_index) const {
-  uint32_t operand = GetRawOperand(operand_index, OperandType::kReg8);
+  OperandType operand_type =
+      Bytecodes::GetOperandType(current_bytecode(), operand_index);
+  DCHECK(operand_type == OperandType::kReg8 ||
+         operand_type == OperandType::kMaybeReg8);
+  uint32_t operand = GetRawOperand(operand_index, operand_type);
   return Register::FromOperand(operand);
 }
 
 
 Handle<Object> BytecodeArrayIterator::GetConstantForIndexOperand(
     int operand_index) const {
   Handle<FixedArray> constants = handle(bytecode_array()->constant_pool());
   return FixedArray::get(constants, GetIndexOperand(operand_index));
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8