move-optimizer.h

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// Copyright 2014 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_BACKEND_MOVE_OPTIMIZER_H_
#define V8_COMPILER_BACKEND_MOVE_OPTIMIZER_H_
 
#include "src/compiler/backend/instruction.h"
#include "src/zone/zone-containers.h"
 
namespace v8 {
namespace internal {
namespace compiler {
 
class V8_EXPORT_PRIVATE MoveOptimizer final {
 public:
  MoveOptimizer(Zone* local_zone, InstructionSequence* code);
  MoveOptimizer(const MoveOptimizer&) = delete;
  MoveOptimizer& operator=(const MoveOptimizer&) = delete;
 
  void Run();
 
 private:
  using MoveOpVector = ZoneVector<MoveOperands*>;
 
  InstructionSequence* code() const { return code_; }
  Zone* local_zone() const { return local_zone_; }
  Zone* code_zone() const { return code()->zone(); }
  MoveOpVector& local_vector() { return local_vector_; }
 
  // Consolidate moves into the first gap.
  void CompressGaps(Instruction* instr);
 
  // Attempt to push down to the last instruction those moves that can.
  void CompressBlock(InstructionBlock* block);
 
  // Consolidate moves into the first gap.
  void CompressMoves(ParallelMove* left, MoveOpVector* right);
 
  // Push down those moves in the gap of from that do not change the
  // semantics of the from instruction, nor the semantics of the moves
  // that remain behind.
  void MigrateMoves(Instruction* to, Instruction* from);
 
  void RemoveClobberedDestinations(Instruction* instruction);
 
  const Instruction* LastInstruction(const InstructionBlock* block) const;
 
  // Consolidate common moves appearing across all predecessors of a block.
  void OptimizeMerge(InstructionBlock* block);
  void FinalizeMoves(Instruction* instr);
 
  Zone* const local_zone_;
  InstructionSequence* const code_;
  MoveOpVector local_vector_;
 
  // Reusable buffers for storing operand sets. We need at most two sets
  // at any given time, so we create two buffers.
  ZoneVector<InstructionOperand> operand_buffer1;
  ZoneVector<InstructionOperand> operand_buffer2;
};
 
}  // namespace compiler
}  // namespace internal
}  // namespace v8
 
#endif  // V8_COMPILER_BACKEND_MOVE_OPTIMIZER_H_