include/llvm/CodeGen/MachineBlockFrequencyInfo.h

   1 //===- MachineBlockFrequencyInfo.h - MBB Frequency Analysis -----*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // Loops should be simplified before this analysis.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_CODEGEN_MACHINEBLOCKFREQUENCYINFO_H
  14 #define LLVM_CODEGEN_MACHINEBLOCKFREQUENCYINFO_H
  15
  16 #include "llvm/ADT/Optional.h"
  17 #include "llvm/CodeGen/MachineFunctionPass.h"
  18 #include "llvm/Support/BlockFrequency.h"
  19 #include <cstdint>
  20 #include <memory>
  21
  22 namespace llvm {
  23
  24 template <class BlockT> class BlockFrequencyInfoImpl;
  25 class MachineBasicBlock;
  26 class MachineBranchProbabilityInfo;
  27 class MachineFunction;
  28 class MachineLoopInfo;
  29 class raw_ostream;
  30
  31 /// MachineBlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation
  32 /// to estimate machine basic block frequencies.
  33 class MachineBlockFrequencyInfo : public MachineFunctionPass {
  34   using ImplType = BlockFrequencyInfoImpl<MachineBasicBlock>;
  35   std::unique_ptr<ImplType> MBFI;
  36
  37 public:
  38   static char ID;
  39
  40   MachineBlockFrequencyInfo();
  41   ~MachineBlockFrequencyInfo() override;
  42
  43   void getAnalysisUsage(AnalysisUsage &AU) const override;
  44
  45   bool runOnMachineFunction(MachineFunction &F) override;
  46
  47   /// calculate - compute block frequency info for the given function.
  48   void calculate(const MachineFunction &F,
  49                  const MachineBranchProbabilityInfo &MBPI,
  50                  const MachineLoopInfo &MLI);
  51
  52   void releaseMemory() override;
  53
  54   /// getblockFreq - Return block frequency. Return 0 if we don't have the
  55   /// information. Please note that initial frequency is equal to 1024. It means
  56   /// that we should not rely on the value itself, but only on the comparison to
  57   /// the other block frequencies. We do this to avoid using of floating points.
  58   ///
  59   BlockFrequency getBlockFreq(const MachineBasicBlock *MBB) const;
  60
  61   Optional<uint64_t> getBlockProfileCount(const MachineBasicBlock *MBB) const;
  62   Optional<uint64_t> getProfileCountFromFreq(uint64_t Freq) const;
  63
  64   bool isIrrLoopHeader(const MachineBasicBlock *MBB);
  65
  66   const MachineFunction *getFunction() const;
  67   const MachineBranchProbabilityInfo *getMBPI() const;
  68   void view(const Twine &Name, bool isSimple = true) const;
  69
  70   // Print the block frequency Freq to OS using the current functions entry
  71   // frequency to convert freq into a relative decimal form.
  72   raw_ostream &printBlockFreq(raw_ostream &OS, const BlockFrequency Freq) const;
  73
  74   // Convenience method that attempts to look up the frequency associated with
  75   // BB and print it to OS.
  76   raw_ostream &printBlockFreq(raw_ostream &OS,
  77                               const MachineBasicBlock *MBB) const;
  78
  79   uint64_t getEntryFreq() const;
  80 };
  81
  82 } // end namespace llvm
  83
  84 #endif // LLVM_CODEGEN_MACHINEBLOCKFREQUENCYINFO_H