AntiDepBreaker.h revision 4a8676e226cc62766c4638cb3dcd128f02e9d128 
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
25namespace llvm {
26
27/// AntiDepBreaker - This class works into conjunction with the
28/// post-RA scheduler to rename registers to break register
29/// anti-dependencies.
30class AntiDepBreaker {
31public:
32  virtual ~AntiDepBreaker();
33
34  /// GetMaxTrials - Return the maximum number of anti-dependence
35  /// breaking attempts that will be made for a block.
36  virtual unsigned GetMaxTrials() =0;
37
38  /// Start - Initialize anti-dep breaking for a new basic block.
39  virtual void StartBlock(MachineBasicBlock *BB) =0;
40
41  /// BreakAntiDependencies - Identifiy anti-dependencies within a
42  /// basic-block region and break them by renaming registers. Return
43  /// the number of anti-dependencies broken.
44  ///
45  virtual unsigned BreakAntiDependencies(std::vector<SUnit>& SUnits,
46                                         MachineBasicBlock::iterator& Begin,
47                                         MachineBasicBlock::iterator& End,
48                                         unsigned InsertPosIndex) =0;
49
50  /// Observe - Update liveness information to account for the current
51  /// instruction, which will not be scheduled.
52  ///
53  virtual void Observe(MachineInstr *MI, unsigned Count,
54                       unsigned InsertPosIndex) =0;
55
56  /// Finish - Finish anti-dep breaking for a basic block.
57  virtual void FinishBlock() =0;
58};
59
60}
61
62#endif
63