[interpreter] Add support for scalable operands.

src/interpreter/bytecode-array-iterator.h

 // 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.
 
 #ifndef V8_INTERPRETER_BYTECODE_ARRAY_ITERATOR_H_
 #define V8_INTERPRETER_BYTECODE_ARRAY_ITERATOR_H_
 
 #include "src/handles.h"
 #include "src/interpreter/bytecodes.h"
 #include "src/objects.h"
 
 namespace v8 {
 namespace internal {
 namespace interpreter {
 
 class BytecodeArrayIterator {
  public:
   explicit BytecodeArrayIterator(Handle<BytecodeArray> bytecode_array);
 
   void Advance();
   bool done() const;
   Bytecode current_bytecode() const;
   int current_bytecode_size() const;
-  void set_current_offset(int offset) { bytecode_offset_ = offset; }
   int current_offset() const { return bytecode_offset_; }
+  OperandScale current_operand_scale() const { return operand_scale_; }
+  int current_prefix_offset() const { return prefix_offset_; }
   const Handle<BytecodeArray>& bytecode_array() const {
     return bytecode_array_;
   }
 
-  int8_t GetImmediateOperand(int operand_index) const;
-  int GetIndexOperand(int operand_index) const;
-  int GetRegisterCountOperand(int operand_index) const;
+  uint32_t GetFlagOperand(int operand_index) const;
+  int32_t GetImmediateOperand(int operand_index) const;
+  uint32_t GetIndexOperand(int operand_index) const;
+  uint32_t GetRegisterCountOperand(int operand_index) const;
   Register GetRegisterOperand(int operand_index) const;
   int GetRegisterOperandRange(int operand_index) const;
+  uint32_t GetRuntimeIdOperand(int operand_index) const;
   Handle<Object> GetConstantForIndexOperand(int operand_index) const;
 
-  // Get the raw byte for the given operand. Note: you should prefer using the
-  // typed versions above which cast the return to an appropriate type.
-  uint32_t GetRawOperand(int operand_index, OperandType operand_type) const;
-
   // Returns the absolute offset of the branch target at the current
   // bytecode. It is an error to call this method if the bytecode is
   // not for a jump or conditional jump.
   int GetJumpTargetOffset() const;
 
  private:
+  uint32_t GetUnsignedOperand(int operand_index,
+                              OperandType operand_type) const;
+  int32_t GetSignedOperand(int operand_index, OperandType operand_type) const;
+
+  void UpdateOperandScale();
+
   Handle<BytecodeArray> bytecode_array_;
   int bytecode_offset_;
+  OperandScale operand_scale_;
+  int prefix_offset_;
 
   DISALLOW_COPY_AND_ASSIGN(BytecodeArrayIterator);
 };
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODE_GRAPH_ITERATOR_H_