[Interpreter] Replace BytecodeRegisterAllocator with a simple bump pointer.

src/interpreter/bytecode-register-optimizer.h

 // Copyright 2016 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_REGISTER_OPTIMIZER_H_
 #define V8_INTERPRETER_BYTECODE_REGISTER_OPTIMIZER_H_
 
 #include "src/interpreter/bytecode-pipeline.h"
 
 namespace v8 {
 namespace internal {
 namespace interpreter {
 
 // An optimization stage for eliminating unnecessary transfers between
 // registers. The bytecode generator uses temporary registers
 // liberally for correctness and convenience and this stage removes
 // transfers that are not required and preserves correctness.
-class BytecodeRegisterOptimizer final : public BytecodePipelineStage,
-                                        public TemporaryRegisterObserver,
-                                        public ZoneObject {
+class BytecodeRegisterOptimizer final
+    : public BytecodePipelineStage,
+      public BytecodeRegisterAllocator::Observer,
+      public ZoneObject {
  public:
   BytecodeRegisterOptimizer(Zone* zone,
-                            TemporaryRegisterAllocator* register_allocator,
-                            int parameter_count,
+                            BytecodeRegisterAllocator* register_allocator,
+                            int fixed_registers_count, int parameter_count,
                             BytecodePipelineStage* next_stage);
   virtual ~BytecodeRegisterOptimizer() {}
 
   // BytecodePipelineStage interface.
   void Write(BytecodeNode* node) override;
   void WriteJump(BytecodeNode* node, BytecodeLabel* label) override;
   void BindLabel(BytecodeLabel* label) override;
   void BindLabel(const BytecodeLabel& target, BytecodeLabel* label) override;
   Handle<BytecodeArray> ToBytecodeArray(
       Isolate* isolate, int register_count, int parameter_count,
       Handle<FixedArray> handler_table) override;
 
  private:
   static const uint32_t kInvalidEquivalenceId = kMaxUInt32;
 
   class RegisterInfo;
 
-  // TemporaryRegisterObserver interface.
-  void TemporaryRegisterFreeEvent(Register reg) override;
+  // BytecodeRegisterAllocator::Observer interface.
+  void RegisterAllocateEvent(Register reg) override;
+  void RegisterListAllocateEvent(RegisterList reg_list) override;
+  void RegisterListFreeEvent(RegisterList reg) override;
 
   // Helpers for BytecodePipelineStage interface.
   void FlushState();
 
   // Update internal state for register transfer from |input| to
   // |output| using |source_info| as source position information if
   // any bytecodes are emitted due to transfer.
   void RegisterTransfer(RegisterInfo* input, RegisterInfo* output,
                         BytecodeSourceInfo* source_info);
 
@@ skipping 89 matching lines @@
   Zone* zone_;
 
   DISALLOW_COPY_AND_ASSIGN(BytecodeRegisterOptimizer);
 };
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_BYTECODE_REGISTER_OPTIMIZER_H_