[interpreter] Introduce bytecode generation pipeline.

src/interpreter/bytecode-array-writer.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_WRITER_H_
+#define V8_INTERPRETER_BYTECODE_ARRAY_WRITER_H_
+
+#include "src/interpreter/bytecode-pipeline.h"
+
+namespace v8 {
+namespace internal {
+namespace interpreter {
+
+// Class for emitting bytecode as the final stage of the bytecode
+// generation pipeline.
+class BytecodeArrayWriter : public BytecodePipelineStage {
+ public:
+  BytecodeArrayWriter(
+      Zone* zone, SourcePositionTableBuilder* source_position_table_builder);
+  virtual ~BytecodeArrayWriter();
+
+  size_t FlushForOffset() override;
+  void LeaveBasicBlock() override;
+  void Write(BytecodeNode* node) override;
+
+  // Get the bytecode vector.
+  ZoneVector<uint8_t>* bytecodes() { return &bytecodes_; }
+
+  // Returns the size in bytes of the frame associated with the
+  // bytecode written.
+  int GetMeasuredFrameSize();
+
+ private:
+  void EmitBytecode(const BytecodeNode* const node);
+  void UpdateSourcePositionTable(const BytecodeNode* const node);
+
+  ZoneVector<uint8_t> bytecodes_;
+  int frame_register_count_;
+  SourcePositionTableBuilder* source_position_table_builder_;
+
+  DISALLOW_COPY_AND_ASSIGN(BytecodeArrayWriter);
+};
+
+}  // namespace interpreter
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_INTERPRETER_BYTECODE_ARRAY_WRITER_H_