[Interpreter] Bytecodes for exchanging registers.

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 57 matching lines @@
   OperandSize size =
       Bytecodes::GetOperandSize(current_bytecode(), operand_index);
   OperandType type = (size == OperandSize::kByte) ? OperandType::kCount8
                                                   : OperandType::kCount16;
   uint32_t operand = GetRawOperand(operand_index, type);
   return static_cast<int>(operand);
 }
 
 
 int BytecodeArrayIterator::GetIndexOperand(int operand_index) const {
-  OperandSize size =
-      Bytecodes::GetOperandSize(current_bytecode(), operand_index);
-  OperandType type =
-      (size == OperandSize::kByte) ? OperandType::kIdx8 : OperandType::kIdx16;
-  uint32_t operand = GetRawOperand(operand_index, type);
+  OperandType operand_type =
+      Bytecodes::GetOperandType(current_bytecode(), operand_index);
+  DCHECK(operand_type == OperandType::kIdx8 ||
+         operand_type == OperandType::kIdx16);
+  uint32_t operand = GetRawOperand(operand_index, operand_type);
   return static_cast<int>(operand);
 }
 
 
 Register BytecodeArrayIterator::GetRegisterOperand(int operand_index) const {
   OperandType operand_type =
       Bytecodes::GetOperandType(current_bytecode(), operand_index);
   DCHECK(operand_type == OperandType::kReg8 ||
-         operand_type == OperandType::kMaybeReg8);
+         operand_type == OperandType::kMaybeReg8 ||
+         operand_type == OperandType::kReg16);
   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));
 }
 
 
 int BytecodeArrayIterator::GetJumpTargetOffset() const {
   Bytecode bytecode = current_bytecode();
   if (interpreter::Bytecodes::IsJumpImmediate(bytecode)) {
     int relative_offset = GetImmediateOperand(0);
     return current_offset() + relative_offset;
   } else if (interpreter::Bytecodes::IsJumpConstant(bytecode)) {
     Smi* smi = Smi::cast(*GetConstantForIndexOperand(0));
     return current_offset() + smi->value();
   } else {
     UNREACHABLE();
     return kMinInt;
   }
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8