[interpreter] Add basic framework for bytecode handler code generation.

src/compiler/interpreter-assembler.h

Index: src/compiler/interpreter-assembler.h
diff --git a/src/compiler/interpreter-assembler.h b/src/compiler/interpreter-assembler.h
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+// 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_COMPILER_INTERPRETER_CODEGEN_H_
+#define V8_COMPILER_INTERPRETER_CODEGEN_H_
+
+// Clients of this interface shouldn't depend on lots of compiler internals.
+// Do not include anything from src/compiler here!
+#include "src/frames.h"
+#include "src/interpreter/bytecodes.h"
+#include "src/smart-pointers.h"
+
+namespace v8 {
+namespace internal {
+
+class Isolate;
+class Zone;
+
+namespace compiler {
+
+class CallDescriptor;
+class CommonOperatorBuilder;
+class Graph;
+class MachineOperatorBuilder;
+class Node;
+class Operator;
+class RawMachineAssembler;
+class Schedule;
+
+class InterpreterAssembler {
+ public:
+  InterpreterAssembler(Isolate* isolate, Zone* zone,
+                       interpreter::Bytecode bytecode);
+  virtual ~InterpreterAssembler();
+
+  Handle<Code> GenerateCode();
+
+  // Constants.
+  Node* Int32Constant(int value);
+  Node* NumberConstant(double value);
+
+  // Returns the bytecode argument |index| for the current bytecode.
+  Node* BytecodeArg(int index);
+
+  // Loads from and stores to the interpreter register file.
+  Node* LoadRegister(int index);
+  Node* LoadRegister(Node* index);
+  Node* StoreRegister(Node* value, int index);
+  Node* StoreRegister(Node* value, Node* index);
+
+  // Dispatch to the bytecode.
+  void Dispatch();
+
+ protected:
+  static const int kFirstRegsterOffsetFromFp =
+      -kPointerSize - StandardFrameConstants::kFixedFrameSizeFromFp;
+
+  // TODO(rmcilroy): Increase this when required.
+  static const int kMaxRegisterIndex = 255;
+
+  // Close the graph.
+  void End();
+
+  // Protected helpers (for testing) which delegate to RawMachineAssembler.
+  CallDescriptor* call_descriptor() const;
+  Graph* graph();
+
+ private:
+  // Returns the pointer to the current bytecode.
+  Node* BytecodePointer();
+  // Returns the pointer to first entry in the interpreter dispatch table.
+  Node* DispatchTablePointer();
+  // Returns the frame pointer for the current function.
+  Node* FramePointer();
+
+  // Returns the offset of register |index|.
+  Node* RegisterFrameOffset(int index);
+  Node* RegisterFrameOffset(Node* index);
+
+  // Returns BytecodePointer() advanced by delta bytecodes. Note: this does not
+  // update BytecodePointer() itself.
+  Node* Advance(int delta);
+
+  // Sets the end node of the graph.
+  void SetEndInput(Node* input);
+
+  // Private helpers which delegate to RawMachineAssembler.
+  Isolate* isolate();
+  Schedule* schedule();
+  MachineOperatorBuilder* machine();
+  CommonOperatorBuilder* common();
+
+  interpreter::Bytecode bytecode_;
+  SmartPointer<RawMachineAssembler> raw_assembler_;
+  Node* end_node_;
+  bool code_generated_;
+
+  DISALLOW_COPY_AND_ASSIGN(InterpreterAssembler);
+};
+
+}  // namespace interpreter
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_COMPILER_INTERPRETER_CODEGEN_H_