contrib/llvm/include/llvm/Analysis/BlockFrequencyInfo.h

   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 <climits>
  22
  23 namespace llvm {
  24
  25 class BranchProbabilityInfo;
  26 class LoopInfo;
  27 template <class BlockT> class BlockFrequencyInfoImpl;
  28
  29 /// BlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to
  30 /// estimate IR basic block frequencies.
  31 class BlockFrequencyInfo {
  32   typedef BlockFrequencyInfoImpl<BasicBlock> ImplType;
  33   std::unique_ptr<ImplType> BFI;
  34
  35   void operator=(const BlockFrequencyInfo &) = delete;
  36   BlockFrequencyInfo(const BlockFrequencyInfo &) = delete;
  37
  38 public:
  39   BlockFrequencyInfo();
  40   BlockFrequencyInfo(const Function &F, const BranchProbabilityInfo &BPI,
  41                      const LoopInfo &LI);
  42   BlockFrequencyInfo(BlockFrequencyInfo &&Arg);
  43
  44   BlockFrequencyInfo &operator=(BlockFrequencyInfo &&RHS);
  45
  46   ~BlockFrequencyInfo();
  47
  48   const Function *getFunction() const;
  49   const BranchProbabilityInfo *getBPI() const;
  50   void view() const;
  51
  52   /// getblockFreq - Return block frequency. Return 0 if we don't have the
  53   /// information. Please note that initial frequency is equal to ENTRY_FREQ. It
  54   /// means that we should not rely on the value itself, but only on the
  55   /// comparison to the other block frequencies. We do this to avoid using of
  56   /// floating points.
  57   BlockFrequency getBlockFreq(const BasicBlock *BB) const;
  58
  59   /// \brief Returns the estimated profile count of \p BB.
  60   /// This computes the relative block frequency of \p BB and multiplies it by
  61   /// the enclosing function's count (if available) and returns the value.
  62   Optional<uint64_t> getBlockProfileCount(const BasicBlock *BB) const;
  63
  64   /// \brief Returns the estimated profile count of \p Freq.
  65   /// This uses the frequency \p Freq and multiplies it by
  66   /// the enclosing function's count (if available) and returns the value.
  67   Optional<uint64_t> getProfileCountFromFreq(uint64_t Freq) const;
  68
  69   // Set the frequency of the given basic block.
  70   void setBlockFreq(const BasicBlock *BB, uint64_t Freq);
  71
  72   /// calculate - compute block frequency info for the given function.
  73   void calculate(const Function &F, const BranchProbabilityInfo &BPI,
  74                  const LoopInfo &LI);
  75
  76   // Print the block frequency Freq to OS using the current functions entry
  77   // frequency to convert freq into a relative decimal form.
  78   raw_ostream &printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const;
  79
  80   // Convenience method that attempts to look up the frequency associated with
  81   // BB and print it to OS.
  82   raw_ostream &printBlockFreq(raw_ostream &OS, const BasicBlock *BB) const;
  83
  84   uint64_t getEntryFreq() const;
  85   void releaseMemory();
  86   void print(raw_ostream &OS) const;
  87 };
  88
  89 /// \brief Analysis pass which computes \c BlockFrequencyInfo.
  90 class BlockFrequencyAnalysis
  91     : public AnalysisInfoMixin<BlockFrequencyAnalysis> {
  92   friend AnalysisInfoMixin<BlockFrequencyAnalysis>;
  93   static AnalysisKey Key;
  94
  95 public:
  96   /// \brief Provide the result typedef for this analysis pass.
  97   typedef BlockFrequencyInfo Result;
  98
  99   /// \brief Run the analysis pass over a function and produce BFI.
 100   Result run(Function &F, FunctionAnalysisManager &AM);
 101 };
 102
 103 /// \brief Printer pass for the \c BlockFrequencyInfo results.
 104 class BlockFrequencyPrinterPass
 105     : public PassInfoMixin<BlockFrequencyPrinterPass> {
 106   raw_ostream &OS;
 107
 108 public:
 109   explicit BlockFrequencyPrinterPass(raw_ostream &OS) : OS(OS) {}
 110   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
 111 };
 112
 113 /// \brief Legacy analysis pass which computes \c BlockFrequencyInfo.
 114 class BlockFrequencyInfoWrapperPass : public FunctionPass {
 115   BlockFrequencyInfo BFI;
 116
 117 public:
 118   static char ID;
 119
 120   BlockFrequencyInfoWrapperPass();
 121   ~BlockFrequencyInfoWrapperPass() override;
 122
 123   BlockFrequencyInfo &getBFI() { return BFI; }
 124   const BlockFrequencyInfo &getBFI() const { return BFI; }
 125
 126   void getAnalysisUsage(AnalysisUsage &AU) const override;
 127
 128   bool runOnFunction(Function &F) override;
 129   void releaseMemory() override;
 130   void print(raw_ostream &OS, const Module *M) const override;
 131 };
 132
 133 }
 134
 135 #endif