1 ///===- LazyMachineBlockFrequencyInfo.h - Lazy Block Frequency -*- 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 /// \file 10 /// This is an alternative analysis pass to MachineBlockFrequencyInfo. The 11 /// difference is that with this pass the block frequencies are not computed 12 /// when the analysis pass is executed but rather when the BFI result is 13 /// explicitly requested by the analysis client. 14 /// 15 ///===---------------------------------------------------------------------===// 16 17 #ifndef LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H 18 #define LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H 19 20 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h" 21 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h" 22 #include "llvm/CodeGen/MachineDominators.h" 23 #include "llvm/CodeGen/MachineLoopInfo.h" 24 25 namespace llvm { 26 /// \brief This is an alternative analysis pass to MachineBlockFrequencyInfo. 27 /// The difference is that with this pass, the block frequencies are not 28 /// computed when the analysis pass is executed but rather when the BFI result 29 /// is explicitly requested by the analysis client. 30 /// 31 /// This works by checking querying if MBFI is available and otherwise 32 /// generating MBFI on the fly. In this case the passes required for (LI, DT) 33 /// are also queried before being computed on the fly. 34 /// 35 /// Note that it is expected that we wouldn't need this functionality for the 36 /// new PM since with the new PM, analyses are executed on demand. 37 38 class LazyMachineBlockFrequencyInfoPass : public MachineFunctionPass { 39 private: 40 /// If generated on the fly this own the instance. 41 mutable std::unique_ptr<MachineBlockFrequencyInfo> OwnedMBFI; 42 43 /// If generated on the fly this own the instance. 44 mutable std::unique_ptr<MachineLoopInfo> OwnedMLI; 45 46 /// If generated on the fly this own the instance. 47 mutable std::unique_ptr<MachineDominatorTree> OwnedMDT; 48 49 /// The function. 50 MachineFunction *MF = nullptr; 51 52 /// \brief Calculate MBFI and all other analyses that's not available and 53 /// required by BFI. 54 MachineBlockFrequencyInfo &calculateIfNotAvailable() const; 55 56 public: 57 static char ID; 58 59 LazyMachineBlockFrequencyInfoPass(); 60 61 /// \brief Compute and return the block frequencies. 62 MachineBlockFrequencyInfo &getBFI() { return calculateIfNotAvailable(); } 63 64 /// \brief Compute and return the block frequencies. 65 const MachineBlockFrequencyInfo &getBFI() const { 66 return calculateIfNotAvailable(); 67 } 68 69 void getAnalysisUsage(AnalysisUsage &AU) const override; 70 71 bool runOnMachineFunction(MachineFunction &F) override; 72 void releaseMemory() override; 73 void print(raw_ostream &OS, const Module *M) const override; 74 }; 75 } 76 #endif 77
