1 //===- BlockFrequencyInfo.h - Block Frequency Analysis ----------*- 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 // Loops should be simplified before this analysis. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_ANALYSIS_BLOCKFREQUENCYINFO_H 15 #define LLVM_ANALYSIS_BLOCKFREQUENCYINFO_H 16 17 #include "llvm/ADT/Optional.h" 18 #include "llvm/IR/PassManager.h" 19 #include "llvm/Pass.h" 20 #include "llvm/Support/BlockFrequency.h" 21 #include <cstdint> 22 #include <memory> 23 24 namespace llvm { 25 26 class BasicBlock; 27 class BranchProbabilityInfo; 28 class Function; 29 class LoopInfo; 30 class Module; 31 class raw_ostream; 32 template <class BlockT> class BlockFrequencyInfoImpl; 33 34 enum PGOViewCountsType { PGOVCT_None, PGOVCT_Graph, PGOVCT_Text }; 35 36 /// BlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to 37 /// estimate IR basic block frequencies. 38 class BlockFrequencyInfo { 39 using ImplType = BlockFrequencyInfoImpl<BasicBlock>; 40 41 std::unique_ptr<ImplType> BFI; 42 43 public: 44 BlockFrequencyInfo(); 45 BlockFrequencyInfo(const Function &F, const BranchProbabilityInfo &BPI, 46 const LoopInfo &LI); 47 BlockFrequencyInfo(const BlockFrequencyInfo &) = delete; 48 BlockFrequencyInfo &operator=(const BlockFrequencyInfo &) = delete; 49 BlockFrequencyInfo(BlockFrequencyInfo &&Arg); 50 BlockFrequencyInfo &operator=(BlockFrequencyInfo &&RHS); 51 ~BlockFrequencyInfo(); 52 53 /// Handle invalidation explicitly. 54 bool invalidate(Function &F, const PreservedAnalyses &PA, 55 FunctionAnalysisManager::Invalidator &); 56 57 const Function *getFunction() const; 58 const BranchProbabilityInfo *getBPI() const; 59 void view() const; 60 61 /// getblockFreq - Return block frequency. Return 0 if we don't have the 62 /// information. Please note that initial frequency is equal to ENTRY_FREQ. It 63 /// means that we should not rely on the value itself, but only on the 64 /// comparison to the other block frequencies. We do this to avoid using of 65 /// floating points. 66 BlockFrequency getBlockFreq(const BasicBlock *BB) const; 67 68 /// Returns the estimated profile count of \p BB. 69 /// This computes the relative block frequency of \p BB and multiplies it by 70 /// the enclosing function's count (if available) and returns the value. 71 Optional<uint64_t> getBlockProfileCount(const BasicBlock *BB) const; 72 73 /// Returns the estimated profile count of \p Freq. 74 /// This uses the frequency \p Freq and multiplies it by 75 /// the enclosing function's count (if available) and returns the value. 76 Optional<uint64_t> getProfileCountFromFreq(uint64_t Freq) const; 77 78 /// Returns true if \p BB is an irreducible loop header 79 /// block. Otherwise false. 80 bool isIrrLoopHeader(const BasicBlock *BB); 81 82 // Set the frequency of the given basic block. 83 void setBlockFreq(const BasicBlock *BB, uint64_t Freq); 84 85 /// Set the frequency of \p ReferenceBB to \p Freq and scale the frequencies 86 /// of the blocks in \p BlocksToScale such that their frequencies relative 87 /// to \p ReferenceBB remain unchanged. 88 void setBlockFreqAndScale(const BasicBlock *ReferenceBB, uint64_t Freq, 89 SmallPtrSetImpl<BasicBlock *> &BlocksToScale); 90 91 /// calculate - compute block frequency info for the given function. 92 void calculate(const Function &F, const BranchProbabilityInfo &BPI, 93 const LoopInfo &LI); 94 95 // Print the block frequency Freq to OS using the current functions entry 96 // frequency to convert freq into a relative decimal form. 97 raw_ostream &printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const; 98 99 // Convenience method that attempts to look up the frequency associated with 100 // BB and print it to OS. 101 raw_ostream &printBlockFreq(raw_ostream &OS, const BasicBlock *BB) const; 102 103 uint64_t getEntryFreq() const; 104 void releaseMemory(); 105 void print(raw_ostream &OS) const; 106 }; 107 108 /// Analysis pass which computes \c BlockFrequencyInfo. 109 class BlockFrequencyAnalysis 110 : public AnalysisInfoMixin<BlockFrequencyAnalysis> { 111 friend AnalysisInfoMixin<BlockFrequencyAnalysis>; 112 113 static AnalysisKey Key; 114 115 public: 116 /// Provide the result type for this analysis pass. 117 using Result = BlockFrequencyInfo; 118 119 /// Run the analysis pass over a function and produce BFI. 120 Result run(Function &F, FunctionAnalysisManager &AM); 121 }; 122 123 /// Printer pass for the \c BlockFrequencyInfo results. 124 class BlockFrequencyPrinterPass 125 : public PassInfoMixin<BlockFrequencyPrinterPass> { 126 raw_ostream &OS; 127 128 public: BlockFrequencyPrinterPass(raw_ostream & OS)129 explicit BlockFrequencyPrinterPass(raw_ostream &OS) : OS(OS) {} 130 131 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); 132 }; 133 134 /// Legacy analysis pass which computes \c BlockFrequencyInfo. 135 class BlockFrequencyInfoWrapperPass : public FunctionPass { 136 BlockFrequencyInfo BFI; 137 138 public: 139 static char ID; 140 141 BlockFrequencyInfoWrapperPass(); 142 ~BlockFrequencyInfoWrapperPass() override; 143 getBFI()144 BlockFrequencyInfo &getBFI() { return BFI; } getBFI()145 const BlockFrequencyInfo &getBFI() const { return BFI; } 146 147 void getAnalysisUsage(AnalysisUsage &AU) const override; 148 149 bool runOnFunction(Function &F) override; 150 void releaseMemory() override; 151 void print(raw_ostream &OS, const Module *M) const override; 152 }; 153 154 } // end namespace llvm 155 156 #endif // LLVM_ANALYSIS_BLOCKFREQUENCYINFO_H 157