1///===- LazyMachineBlockFrequencyInfo.h - Lazy Block Frequency -*- C++ -*--===// 2/// 3/// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4/// See https://llvm.org/LICENSE.txt for license information. 5/// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6/// 7///===---------------------------------------------------------------------===// 8/// \file 9/// This is an alternative analysis pass to MachineBlockFrequencyInfo. The 10/// difference is that with this pass the block frequencies are not computed 11/// when the analysis pass is executed but rather when the BFI result is 12/// explicitly requested by the analysis client. 13/// 14///===---------------------------------------------------------------------===// 15 16#ifndef LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H 17#define LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H 18 19#include "llvm/CodeGen/MachineBlockFrequencyInfo.h" 20#include "llvm/CodeGen/MachineBranchProbabilityInfo.h" 21#include "llvm/CodeGen/MachineDominators.h" 22#include "llvm/CodeGen/MachineLoopInfo.h" 23 24namespace llvm { 25/// This is an alternative analysis pass to MachineBlockFrequencyInfo. 26/// The difference is that with this pass, the block frequencies are not 27/// computed when the analysis pass is executed but rather when the BFI result 28/// is explicitly requested by the analysis client. 29/// 30/// This works by checking querying if MBFI is available and otherwise 31/// generating MBFI on the fly. In this case the passes required for (LI, DT) 32/// are also queried before being computed on the fly. 33/// 34/// Note that it is expected that we wouldn't need this functionality for the 35/// new PM since with the new PM, analyses are executed on demand. 36 37class LazyMachineBlockFrequencyInfoPass : public MachineFunctionPass { 38private: 39 /// If generated on the fly this own the instance. 40 mutable std::unique_ptr<MachineBlockFrequencyInfo> OwnedMBFI; 41 42 /// If generated on the fly this own the instance. 43 mutable std::unique_ptr<MachineLoopInfo> OwnedMLI; 44 45 /// If generated on the fly this own the instance. 46 mutable std::unique_ptr<MachineDominatorTree> OwnedMDT; 47 48 /// The function. 49 MachineFunction *MF = nullptr; 50 51 /// Calculate MBFI and all other analyses that's not available and 52 /// required by BFI. 53 MachineBlockFrequencyInfo &calculateIfNotAvailable() const; 54 55public: 56 static char ID; 57 58 LazyMachineBlockFrequencyInfoPass(); 59 60 /// Compute and return the block frequencies. 61 MachineBlockFrequencyInfo &getBFI() { return calculateIfNotAvailable(); } 62 63 /// Compute and return the block frequencies. 64 const MachineBlockFrequencyInfo &getBFI() const { 65 return calculateIfNotAvailable(); 66 } 67 68 void getAnalysisUsage(AnalysisUsage &AU) const override; 69 70 bool runOnMachineFunction(MachineFunction &F) override; 71 void releaseMemory() override; 72 void print(raw_ostream &OS, const Module *M) const override; 73}; 74} 75#endif 76