1 ///===- LazyMachineBlockFrequencyInfo.h - Lazy Block Frequency -*- C++ -*--===//
3 /// The LLVM Compiler Infrastructure
5 /// This file is distributed under the University of Illinois Open Source
6 /// License. See LICENSE.TXT for details.
8 ///===---------------------------------------------------------------------===//
10 /// This is an alternative analysis pass to MachineBlockFrequencyInfo. The
11 /// difference is that with this pass the block frequencies are not computed
12 /// when the analysis pass is executed but rather when the BFI result is
13 /// explicitly requested by the analysis client.
15 ///===---------------------------------------------------------------------===//
17 #ifndef LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H
18 #define LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H
20 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
21 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
22 #include "llvm/CodeGen/MachineDominators.h"
23 #include "llvm/CodeGen/MachineLoopInfo.h"
26 /// \brief This is an alternative analysis pass to MachineBlockFrequencyInfo.
27 /// The difference is that with this pass, the block frequencies are not
28 /// computed when the analysis pass is executed but rather when the BFI result
29 /// is explicitly requested by the analysis client.
31 /// This works by checking querying if MBFI is available and otherwise
32 /// generating MBFI on the fly. In this case the passes required for (LI, DT)
33 /// are also queried before being computed on the fly.
35 /// Note that it is expected that we wouldn't need this functionality for the
36 /// new PM since with the new PM, analyses are executed on demand.
38 class LazyMachineBlockFrequencyInfoPass : public MachineFunctionPass {
40 /// If generated on the fly this own the instance.
41 mutable std::unique_ptr<MachineBlockFrequencyInfo> OwnedMBFI;
43 /// If generated on the fly this own the instance.
44 mutable std::unique_ptr<MachineLoopInfo> OwnedMLI;
46 /// If generated on the fly this own the instance.
47 mutable std::unique_ptr<MachineDominatorTree> OwnedMDT;
50 MachineFunction *MF = nullptr;
52 /// \brief Calculate MBFI and all other analyses that's not available and
54 MachineBlockFrequencyInfo &calculateIfNotAvailable() const;
59 LazyMachineBlockFrequencyInfoPass();
61 /// \brief Compute and return the block frequencies.
62 MachineBlockFrequencyInfo &getBFI() { return calculateIfNotAvailable(); }
64 /// \brief Compute and return the block frequencies.
65 const MachineBlockFrequencyInfo &getBFI() const {
66 return calculateIfNotAvailable();
69 void getAnalysisUsage(AnalysisUsage &AU) const override;
71 bool runOnMachineFunction(MachineFunction &F) override;
72 void releaseMemory() override;
73 void print(raw_ostream &OS, const Module *M) const override;