[Interpreter] Add support for short (16 bit) operands.

src/interpreter/bytecode-array-iterator.cc

Index: src/interpreter/bytecode-array-iterator.cc
diff --git a/src/interpreter/bytecode-array-iterator.cc b/src/interpreter/bytecode-array-iterator.cc
index dc49308fbe87e6e449319314c830521c37541f2b..d4f277307936b0eab5fe56617f1469bd90ee44f0 100644
--- a/src/interpreter/bytecode-array-iterator.cc
+++ b/src/interpreter/bytecode-array-iterator.cc
@@ -32,31 +32,45 @@ Bytecode BytecodeArrayIterator::current_bytecode() const {
 }
 
 
-uint8_t BytecodeArrayIterator::GetRawOperand(int operand_index,
-                                             OperandType operand_type) const {
+uint32_t BytecodeArrayIterator::GetRawOperand(int operand_index,
+                                              OperandType operand_type) const {
   DCHECK_GE(operand_index, 0);
   DCHECK_LT(operand_index, Bytecodes::NumberOfOperands(current_bytecode()));
   DCHECK_EQ(operand_type,
             Bytecodes::GetOperandType(current_bytecode(), operand_index));
-  int operands_start = bytecode_offset_ + 1;
-  return bytecode_array()->get(operands_start + operand_index);
+  uint8_t* operand_start =
+      bytecode_array()->GetFirstBytecodeAddress() + bytecode_offset_ +
+      Bytecodes::GetOperandOffset(current_bytecode(), operand_index);
+  switch (Bytecodes::SizeOfOperand(operand_type)) {
+    default:
+    case OperandSize::kNone:
+      UNREACHABLE();
+    case OperandSize::kByte:
+      return static_cast<uint32_t>(*operand_start);
+    case OperandSize::kShort:
+      return Bytecodes::ShortOperandFromBytes(operand_start);
+  }
 }
 
 
-int8_t BytecodeArrayIterator::GetSmi8Operand(int operand_index) const {
-  uint8_t operand = GetRawOperand(operand_index, OperandType::kImm8);
+int8_t BytecodeArrayIterator::GetImmediateOperand(int operand_index) const {
+  uint32_t operand = GetRawOperand(operand_index, OperandType::kImm8);
   return static_cast<int8_t>(operand);
 }
 
 
 int BytecodeArrayIterator::GetIndexOperand(int operand_index) const {
-  uint8_t operand = GetRawOperand(operand_index, OperandType::kIdx);
+  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 {
-  uint8_t operand = GetRawOperand(operand_index, OperandType::kReg);
+  uint32_t operand = GetRawOperand(operand_index, OperandType::kReg8);
   return Register::FromOperand(operand);
 }