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