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_MOVE_OPTIMIZER_
6#define V8_COMPILER_MOVE_OPTIMIZER_
7
8#include "src/compiler/instruction.h"
9#include "src/globals.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  void Run();
20
21 private:
22  typedef ZoneVector<MoveOperands*> MoveOpVector;
23  typedef ZoneVector<Instruction*> Instructions;
24
25  InstructionSequence* code() const { return code_; }
26  Zone* local_zone() const { return local_zone_; }
27  Zone* code_zone() const { return code()->zone(); }
28  MoveOpVector& local_vector() { return local_vector_; }
29
30  // Consolidate moves into the first gap.
31  void CompressGaps(Instruction* instr);
32
33  // Attempt to push down to the last instruction those moves that can.
34  void CompressBlock(InstructionBlock* block);
35
36  // Consolidate moves into the first gap.
37  void CompressMoves(ParallelMove* left, MoveOpVector* right);
38
39  // Push down those moves in the gap of from that do not change the
40  // semantics of the from instruction, nor the semantics of the moves
41  // that remain behind.
42  void MigrateMoves(Instruction* to, Instruction* from);
43
44  void RemoveClobberedDestinations(Instruction* instruction);
45
46  const Instruction* LastInstruction(const InstructionBlock* block) const;
47
48  // Consolidate common moves appearing accross all predecessors of a block.
49  void OptimizeMerge(InstructionBlock* block);
50  void FinalizeMoves(Instruction* instr);
51
52  Zone* const local_zone_;
53  InstructionSequence* const code_;
54  MoveOpVector local_vector_;
55
56  // Reusable buffers for storing operand sets. We need at most two sets
57  // at any given time, so we create two buffers.
58  ZoneVector<InstructionOperand> operand_buffer1;
59  ZoneVector<InstructionOperand> operand_buffer2;
60
61  DISALLOW_COPY_AND_ASSIGN(MoveOptimizer);
62};
63
64}  // namespace compiler
65}  // namespace internal
66}  // namespace v8
67
68#endif  // V8_COMPILER_MOVE_OPTIMIZER_
69