1 //===- BlockFrequencyInfo.h - Block Frequency Analysis ----------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Loops should be simplified before this analysis.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_ANALYSIS_BLOCKFREQUENCYINFO_H
15 #define LLVM_ANALYSIS_BLOCKFREQUENCYINFO_H
17 #include "llvm/ADT/Optional.h"
18 #include "llvm/IR/PassManager.h"
19 #include "llvm/Pass.h"
20 #include "llvm/Support/BlockFrequency.h"
27 class BranchProbabilityInfo;
32 template <class BlockT> class BlockFrequencyInfoImpl;
34 enum PGOViewCountsType { PGOVCT_None, PGOVCT_Graph, PGOVCT_Text };
36 /// BlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to
37 /// estimate IR basic block frequencies.
38 class BlockFrequencyInfo {
39 using ImplType = BlockFrequencyInfoImpl<BasicBlock>;
41 std::unique_ptr<ImplType> BFI;
45 BlockFrequencyInfo(const Function &F, const BranchProbabilityInfo &BPI,
47 BlockFrequencyInfo(const BlockFrequencyInfo &) = delete;
48 BlockFrequencyInfo &operator=(const BlockFrequencyInfo &) = delete;
49 BlockFrequencyInfo(BlockFrequencyInfo &&Arg);
50 BlockFrequencyInfo &operator=(BlockFrequencyInfo &&RHS);
51 ~BlockFrequencyInfo();
53 /// Handle invalidation explicitly.
54 bool invalidate(Function &F, const PreservedAnalyses &PA,
55 FunctionAnalysisManager::Invalidator &);
57 const Function *getFunction() const;
58 const BranchProbabilityInfo *getBPI() const;
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
66 BlockFrequency getBlockFreq(const BasicBlock *BB) const;
68 /// \brief 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;
73 /// \brief 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;
78 /// \brief Returns true if \p BB is an irreducible loop header
79 /// block. Otherwise false.
80 bool isIrrLoopHeader(const BasicBlock *BB);
82 // Set the frequency of the given basic block.
83 void setBlockFreq(const BasicBlock *BB, uint64_t Freq);
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);
91 /// calculate - compute block frequency info for the given function.
92 void calculate(const Function &F, const BranchProbabilityInfo &BPI,
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;
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;
103 uint64_t getEntryFreq() const;
104 void releaseMemory();
105 void print(raw_ostream &OS) const;
108 /// \brief Analysis pass which computes \c BlockFrequencyInfo.
109 class BlockFrequencyAnalysis
110 : public AnalysisInfoMixin<BlockFrequencyAnalysis> {
111 friend AnalysisInfoMixin<BlockFrequencyAnalysis>;
113 static AnalysisKey Key;
116 /// \brief Provide the result type for this analysis pass.
117 using Result = BlockFrequencyInfo;
119 /// \brief Run the analysis pass over a function and produce BFI.
120 Result run(Function &F, FunctionAnalysisManager &AM);
123 /// \brief Printer pass for the \c BlockFrequencyInfo results.
124 class BlockFrequencyPrinterPass
125 : public PassInfoMixin<BlockFrequencyPrinterPass> {
129 explicit BlockFrequencyPrinterPass(raw_ostream &OS) : OS(OS) {}
131 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
134 /// \brief Legacy analysis pass which computes \c BlockFrequencyInfo.
135 class BlockFrequencyInfoWrapperPass : public FunctionPass {
136 BlockFrequencyInfo BFI;
141 BlockFrequencyInfoWrapperPass();
142 ~BlockFrequencyInfoWrapperPass() override;
144 BlockFrequencyInfo &getBFI() { return BFI; }
145 const BlockFrequencyInfo &getBFI() const { return BFI; }
147 void getAnalysisUsage(AnalysisUsage &AU) const override;
149 bool runOnFunction(Function &F) override;
150 void releaseMemory() override;
151 void print(raw_ostream &OS, const Module *M) const override;
154 } // end namespace llvm
156 #endif // LLVM_ANALYSIS_BLOCKFREQUENCYINFO_H