[Intepreter] Addition of BytecodeArrayBuilder and accumulator based bytecodes.

src/interpreter/bytecode-array-builder.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_BUILDER_H_
+#define V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_
+
+#include <vector>
+
+#include "src/interpreter/bytecodes.h"
+
+namespace v8 {
+namespace internal {
+
+class Isolate;
+
+namespace interpreter {
+
+class BytecodeArrayBuilder {
+ public:
+  explicit BytecodeArrayBuilder(Isolate* isolate);
+  Handle<BytecodeArray> ToBytecodeArray() const;
+
+  void BinaryOperation(Token::Value binop, int reg);

[rmcilroy, 2015/07/30 10:12:25]

optional suggestion - is it worth returning "this" from each builder op to allow
builder style like:

builder().LoadLiteral()
    .LoadUndefined()
    .LoadFalse()

?

[oth, 2015/07/30 15:38:42]

Done.

+  void LoadLiteral(v8::internal::Smi* value);

[rmcilroy, 2015/07/30 10:12:25]

nit - add some section header comments (e.g., "Load constants", "register
management", etc.).

[oth, 2015/07/30 15:38:42]

Done.

+  void LoadUndefined();
+  void LoadNull();
+  void LoadTheHole();
+  void LoadTrue();
+  void LoadFalse();
+  void LoadAccumulatorWithRegister(int reg);
+  void StoreAccumulatorInRegister(int reg);
+  void Return();
+
+  int AllocateScratchRegister();
+  void FreeScratchRegister(int reg);
+
+  void set_stack_slots(int slots);
+
+ private:
+  static Bytecode BytecodeFor(Token::Value op);
+  void Output(Bytecode bytecode, uint8_t r0, uint8_t r1, uint8_t r2);
+  void Output(Bytecode bytecode, uint8_t r0, uint8_t r1);
+  void Output(Bytecode bytecode, uint8_t r0);
+  void Output(Bytecode bytecode);
+
+  Isolate* isolate_;
+  std::vector<uint8_t> bytecodes_;
+
+  int max_registers_;
+  int scratch_register_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(BytecodeArrayBuilder);
+};
+
+}  // namespace interpreter
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_INTERPRETER_BYTECODE_ARRAY_BUILDER_H_