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   /// Handle invalidation explicitly.
  49   bool invalidate(Function &F, const PreservedAnalyses &PA,
  50                   FunctionAnalysisManager::Invalidator &);
  51
  52   const Function *getFunction() const;
  53   const BranchProbabilityInfo *getBPI() const;
  54   void view() const;
  55
  56   /// getblockFreq - Return block frequency. Return 0 if we don't have the
  57   /// information. Please note that initial frequency is equal to ENTRY_FREQ. It
  58   /// means that we should not rely on the value itself, but only on the
  59   /// comparison to the other block frequencies. We do this to avoid using of
  60   /// floating points.
  61   BlockFrequency getBlockFreq(const BasicBlock *BB) const;
  62
  63   /// \brief Returns the estimated profile count of \p BB.
  64   /// This computes the relative block frequency of \p BB and multiplies it by
  65   /// the enclosing function's count (if available) and returns the value.
  66   Optional<uint64_t> getBlockProfileCount(const BasicBlock *BB) const;
  67
  68   /// \brief Returns the estimated profile count of \p Freq.
  69   /// This uses the frequency \p Freq and multiplies it by
  70   /// the enclosing function's count (if available) and returns the value.
  71   Optional<uint64_t> getProfileCountFromFreq(uint64_t Freq) const;
  72
  73   // Set the frequency of the given basic block.
  74   void setBlockFreq(const BasicBlock *BB, uint64_t Freq);
  75
  76   /// Set the frequency of \p ReferenceBB to \p Freq and scale the frequencies
  77   /// of the blocks in \p BlocksToScale such that their frequencies relative
  78   /// to \p ReferenceBB remain unchanged.
  79   void setBlockFreqAndScale(const BasicBlock *ReferenceBB, uint64_t Freq,
  80                             SmallPtrSetImpl<BasicBlock *> &BlocksToScale);
  81
  82   /// calculate - compute block frequency info for the given function.
  83   void calculate(const Function &F, const BranchProbabilityInfo &BPI,
  84                  const LoopInfo &LI);
  85
  86   // Print the block frequency Freq to OS using the current functions entry
  87   // frequency to convert freq into a relative decimal form.
  88   raw_ostream &printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const;
  89
  90   // Convenience method that attempts to look up the frequency associated with
  91   // BB and print it to OS.
  92   raw_ostream &printBlockFreq(raw_ostream &OS, const BasicBlock *BB) const;
  93
  94   uint64_t getEntryFreq() const;
  95   void releaseMemory();
  96   void print(raw_ostream &OS) const;
  97 };
  98
  99 /// \brief Analysis pass which computes \c BlockFrequencyInfo.
 100 class BlockFrequencyAnalysis
 101     : public AnalysisInfoMixin<BlockFrequencyAnalysis> {
 102   friend AnalysisInfoMixin<BlockFrequencyAnalysis>;
 103   static AnalysisKey Key;
 104
 105 public:
 106   /// \brief Provide the result typedef for this analysis pass.
 107   typedef BlockFrequencyInfo Result;
 108
 109   /// \brief Run the analysis pass over a function and produce BFI.
 110   Result run(Function &F, FunctionAnalysisManager &AM);
 111 };
 112
 113 /// \brief Printer pass for the \c BlockFrequencyInfo results.
 114 class BlockFrequencyPrinterPass
 115     : public PassInfoMixin<BlockFrequencyPrinterPass> {
 116   raw_ostream &OS;
 117
 118 public:
 119   explicit BlockFrequencyPrinterPass(raw_ostream &OS) : OS(OS) {}
 120   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
 121 };
 122
 123 /// \brief Legacy analysis pass which computes \c BlockFrequencyInfo.
 124 class BlockFrequencyInfoWrapperPass : public FunctionPass {
 125   BlockFrequencyInfo BFI;
 126
 127 public:
 128   static char ID;
 129
 130   BlockFrequencyInfoWrapperPass();
 131   ~BlockFrequencyInfoWrapperPass() override;
 132
 133   BlockFrequencyInfo &getBFI() { return BFI; }
 134   const BlockFrequencyInfo &getBFI() const { return BFI; }
 135
 136   void getAnalysisUsage(AnalysisUsage &AU) const override;
 137
 138   bool runOnFunction(Function &F) override;
 139   void releaseMemory() override;
 140   void print(raw_ostream &OS, const Module *M) const override;
 141 };
 142
 143 }
 144
 145 #endif