1// Copyright 2014 the V8 project authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef V8_COMPILER_BACKEND_MOVE_OPTIMIZER_H_
6#define V8_COMPILER_BACKEND_MOVE_OPTIMIZER_H_
7
8#include "src/common/globals.h"
9#include "src/compiler/backend/instruction.h"
10#include "src/zone/zone-containers.h"
11
12namespace v8 {
13namespace internal {
14namespace compiler {
15
16class V8_EXPORT_PRIVATE MoveOptimizer final {
17 public:
18  MoveOptimizer(Zone* local_zone, InstructionSequence* code);
19  MoveOptimizer(const MoveOptimizer&) = delete;
20  MoveOptimizer& operator=(const MoveOptimizer&) = delete;
21
22  void Run();
23
24 private:
25  using MoveOpVector = ZoneVector<MoveOperands*>;
26  using Instructions = ZoneVector<Instruction*>;
27
28  InstructionSequence* code() const { return code_; }
29  Zone* local_zone() const { return local_zone_; }
30  Zone* code_zone() const { return code()->zone(); }
31  MoveOpVector& local_vector() { return local_vector_; }
32
33  // Consolidate moves into the first gap.
34  void CompressGaps(Instruction* instr);
35
36  // Attempt to push down to the last instruction those moves that can.
37  void CompressBlock(InstructionBlock* block);
38
39  // Consolidate moves into the first gap.
40  void CompressMoves(ParallelMove* left, MoveOpVector* right);
41
42  // Push down those moves in the gap of from that do not change the
43  // semantics of the from instruction, nor the semantics of the moves
44  // that remain behind.
45  void MigrateMoves(Instruction* to, Instruction* from);
46
47  void RemoveClobberedDestinations(Instruction* instruction);
48
49  const Instruction* LastInstruction(const InstructionBlock* block) const;
50
51  // Consolidate common moves appearing across all predecessors of a block.
52  void OptimizeMerge(InstructionBlock* block);
53  void FinalizeMoves(Instruction* instr);
54
55  Zone* const local_zone_;
56  InstructionSequence* const code_;
57  MoveOpVector local_vector_;
58
59  // Reusable buffers for storing operand sets. We need at most two sets
60  // at any given time, so we create two buffers.
61  ZoneVector<InstructionOperand> operand_buffer1;
62  ZoneVector<InstructionOperand> operand_buffer2;
63};
64
65}  // namespace compiler
66}  // namespace internal
67}  // namespace v8
68
69#endif  // V8_COMPILER_BACKEND_MOVE_OPTIMIZER_H_
70