AntiDepBreaker.h revision 8450a9090b38c0faf1401326dd7ec95358e995cc 
1//=- llvm/CodeGen/AntiDepBreaker.h - Anti-Dependence Breaking -*- C++ -*-=//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the AntiDepBreaker class, which implements
11// anti-dependence breaking heuristics for post-register-allocation scheduling.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_CODEGEN_ANTIDEPBREAKER_H
16#define LLVM_CODEGEN_ANTIDEPBREAKER_H
17
18#include "llvm/CodeGen/MachineBasicBlock.h"
19#include "llvm/CodeGen/MachineFrameInfo.h"
20#include "llvm/CodeGen/MachineFunction.h"
21#include "llvm/CodeGen/MachineRegisterInfo.h"
22#include "llvm/CodeGen/ScheduleDAG.h"
23#include "llvm/Target/TargetRegisterInfo.h"
24#include "llvm/ADT/SmallSet.h"
25#include "llvm/ADT/SmallVector.h"
26#include <map>
27
28namespace llvm {
29
30/// AntiDepBreaker - This class works into conjunction with the
31/// post-RA scheduler to rename registers to break register
32/// anti-dependencies.
33class AntiDepBreaker {
34public:
35  typedef SmallSet<unsigned, 4> AntiDepRegSet;
36  typedef SmallVector<unsigned, 4> AntiDepRegVector;
37  typedef std::map<SUnit *, AntiDepRegVector> CandidateMap;
38
39  virtual ~AntiDepBreaker();
40
41  /// GetMaxTrials - Return the maximum number of anti-dependence
42  /// breaking attempts that will be made for a block.
43  virtual unsigned GetMaxTrials() =0;
44
45  /// NeedCandidates - Return true if the schedule must provide
46  /// candidates with BreakAntiDependencies().
47  virtual bool NeedCandidates() =0;
48
49  /// Start - Initialize anti-dep breaking for a new basic block.
50  virtual void StartBlock(MachineBasicBlock *BB) =0;
51
52  /// BreakAntiDependencies - Identifiy anti-dependencies within a
53  /// basic-block region and break them by renaming registers. Return
54  /// the number of anti-dependencies broken.
55  ///
56  virtual unsigned BreakAntiDependencies(std::vector<SUnit>& SUnits,
57                                CandidateMap& Candidates,
58                                MachineBasicBlock::iterator& Begin,
59                                MachineBasicBlock::iterator& End,
60                                unsigned InsertPosIndex) =0;
61
62  /// Observe - Update liveness information to account for the current
63  /// instruction, which will not be scheduled.
64  ///
65  virtual void Observe(MachineInstr *MI, unsigned Count,
66                       unsigned InsertPosIndex) =0;
67
68  /// Finish - Finish anti-dep breaking for a basic block.
69  virtual void FinishBlock() =0;
70};
71
72}
73
74#endif
75