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/Pass.h"
  18 #include "llvm/Support/BlockFrequency.h"
  19 #include <climits>
  20
  21 namespace llvm {
  22
  23 class BranchProbabilityInfo;
  24 class LoopInfo;
  25 template <class BlockT> class BlockFrequencyInfoImpl;
  26
  27 /// BlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to
  28 /// estimate IR basic block frequencies.
  29 class BlockFrequencyInfo {
  30   typedef BlockFrequencyInfoImpl<BasicBlock> ImplType;
  31   std::unique_ptr<ImplType> BFI;
  32
  33 public:
  34   BlockFrequencyInfo();
  35   BlockFrequencyInfo(const Function &F, const BranchProbabilityInfo &BPI,
  36                      const LoopInfo &LI);
  37
  38   const Function *getFunction() const;
  39   void view() const;
  40
  41   /// getblockFreq - Return block frequency. Return 0 if we don't have the
  42   /// information. Please note that initial frequency is equal to ENTRY_FREQ. It
  43   /// means that we should not rely on the value itself, but only on the
  44   /// comparison to the other block frequencies. We do this to avoid using of
  45   /// floating points.
  46   BlockFrequency getBlockFreq(const BasicBlock *BB) const;
  47
  48   /// calculate - compute block frequency info for the given function.
  49   void calculate(const Function &F, const BranchProbabilityInfo &BPI,
  50                  const LoopInfo &LI);
  51
  52   // Print the block frequency Freq to OS using the current functions entry
  53   // frequency to convert freq into a relative decimal form.
  54   raw_ostream &printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const;
  55
  56   // Convenience method that attempts to look up the frequency associated with
  57   // BB and print it to OS.
  58   raw_ostream &printBlockFreq(raw_ostream &OS, const BasicBlock *BB) const;
  59
  60   uint64_t getEntryFreq() const;
  61   void releaseMemory();
  62   void print(raw_ostream &OS) const;
  63 };
  64
  65 /// \brief Legacy analysis pass which computes \c BlockFrequencyInfo.
  66 class BlockFrequencyInfoWrapperPass : public FunctionPass {
  67   BlockFrequencyInfo BFI;
  68
  69 public:
  70   static char ID;
  71
  72   BlockFrequencyInfoWrapperPass();
  73   ~BlockFrequencyInfoWrapperPass() override;
  74
  75   BlockFrequencyInfo &getBFI() { return BFI; }
  76   const BlockFrequencyInfo &getBFI() const { return BFI; }
  77
  78   void getAnalysisUsage(AnalysisUsage &AU) const override;
  79
  80   bool runOnFunction(Function &F) override;
  81   void releaseMemory() override;
  82   void print(raw_ostream &OS, const Module *M) const override;
  83 };
  84
  85 }
  86
  87 #endif