move-optimizer.h 2.16 KB
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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.

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#ifndef V8_COMPILER_BACKEND_MOVE_OPTIMIZER_H_
#define V8_COMPILER_BACKEND_MOVE_OPTIMIZER_H_
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#include "src/compiler/backend/instruction.h"
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#include "src/globals.h"
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#include "src/zone/zone-containers.h"
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namespace v8 {
namespace internal {
namespace compiler {

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class V8_EXPORT_PRIVATE MoveOptimizer final {
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 public:
  MoveOptimizer(Zone* local_zone, InstructionSequence* code);
  void Run();

 private:
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  using MoveOpVector = ZoneVector<MoveOperands*>;
  using Instructions = ZoneVector<Instruction*>;
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  InstructionSequence* code() const { return code_; }
  Zone* local_zone() const { return local_zone_; }
  Zone* code_zone() const { return code()->zone(); }
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  MoveOpVector& local_vector() { return local_vector_; }
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  // 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);

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  const Instruction* LastInstruction(const InstructionBlock* block) const;
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  // Consolidate common moves appearing across all predecessors of a block.
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  void OptimizeMerge(InstructionBlock* block);
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  void FinalizeMoves(Instruction* instr);
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  Zone* const local_zone_;
  InstructionSequence* const code_;
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  MoveOpVector local_vector_;
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  // 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;

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  DISALLOW_COPY_AND_ASSIGN(MoveOptimizer);
};

}  // namespace compiler
}  // namespace internal
}  // namespace v8

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#endif  // V8_COMPILER_BACKEND_MOVE_OPTIMIZER_H_