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       1             : //===- MachineBlockFrequencyInfo.h - MBB 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_CODEGEN_MACHINEBLOCKFREQUENCYINFO_H
      15             : #define LLVM_CODEGEN_MACHINEBLOCKFREQUENCYINFO_H
      16             : 
      17             : #include "llvm/ADT/Optional.h"
      18             : #include "llvm/CodeGen/MachineFunctionPass.h"
      19             : #include "llvm/Support/BlockFrequency.h"
      20             : #include <cstdint>
      21             : #include <memory>
      22             : 
      23             : namespace llvm {
      24             : 
      25             : template <class BlockT> class BlockFrequencyInfoImpl;
      26             : class MachineBasicBlock;
      27             : class MachineBranchProbabilityInfo;
      28             : class MachineFunction;
      29             : class MachineLoopInfo;
      30             : class raw_ostream;
      31             : 
      32             : /// MachineBlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation
      33             : /// to estimate machine basic block frequencies.
      34      171314 : class MachineBlockFrequencyInfo : public MachineFunctionPass {
      35             :   using ImplType = BlockFrequencyInfoImpl<MachineBasicBlock>;
      36             :   std::unique_ptr<ImplType> MBFI;
      37             : 
      38             : public:
      39             :   static char ID;
      40             : 
      41             :   MachineBlockFrequencyInfo();
      42             :   ~MachineBlockFrequencyInfo() override;
      43             : 
      44             :   void getAnalysisUsage(AnalysisUsage &AU) const override;
      45             : 
      46             :   bool runOnMachineFunction(MachineFunction &F) override;
      47             : 
      48             :   /// calculate - compute block frequency info for the given function.
      49             :   void calculate(const MachineFunction &F,
      50             :                  const MachineBranchProbabilityInfo &MBPI,
      51             :                  const MachineLoopInfo &MLI);
      52             : 
      53             :   void releaseMemory() override;
      54             : 
      55             :   /// getblockFreq - Return block frequency. Return 0 if we don't have the
      56             :   /// information. Please note that initial frequency is equal to 1024. It means
      57             :   /// that we should not rely on the value itself, but only on the comparison to
      58             :   /// the other block frequencies. We do this to avoid using of floating points.
      59             :   ///
      60             :   BlockFrequency getBlockFreq(const MachineBasicBlock *MBB) const;
      61             : 
      62             :   Optional<uint64_t> getBlockProfileCount(const MachineBasicBlock *MBB) const;
      63             :   Optional<uint64_t> getProfileCountFromFreq(uint64_t Freq) const;
      64             : 
      65             :   bool isIrrLoopHeader(const MachineBasicBlock *MBB);
      66             : 
      67             :   const MachineFunction *getFunction() const;
      68             :   const MachineBranchProbabilityInfo *getMBPI() const;
      69             :   void view(const Twine &Name, bool isSimple = true) const;
      70             : 
      71             :   // Print the block frequency Freq to OS using the current functions entry
      72             :   // frequency to convert freq into a relative decimal form.
      73             :   raw_ostream &printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const;
      74             : 
      75             :   // Convenience method that attempts to look up the frequency associated with
      76             :   // BB and print it to OS.
      77             :   raw_ostream &printBlockFreq(raw_ostream &OS,
      78             :                               const MachineBasicBlock *MBB) const;
      79             : 
      80             :   uint64_t getEntryFreq() const;
      81             : };
      82             : 
      83             : } // end namespace llvm
      84             : 
      85             : #endif // LLVM_CODEGEN_MACHINEBLOCKFREQUENCYINFO_H