LLVM  9.0.0svn
LazyMachineBlockFrequencyInfo.h
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1 ///===- LazyMachineBlockFrequencyInfo.h - Lazy Block Frequency -*- 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 /// \file
9 /// This is an alternative analysis pass to MachineBlockFrequencyInfo. The
10 /// difference is that with this pass the block frequencies are not computed
11 /// when the analysis pass is executed but rather when the BFI result is
12 /// explicitly requested by the analysis client.
13 ///
14 ///===---------------------------------------------------------------------===//
15 
16 #ifndef LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H
17 #define LLVM_ANALYSIS_LAZYMACHINEBLOCKFREQUENCYINFO_H
18 
23 
24 namespace llvm {
25 /// This is an alternative analysis pass to MachineBlockFrequencyInfo.
26 /// The difference is that with this pass, the block frequencies are not
27 /// computed when the analysis pass is executed but rather when the BFI result
28 /// is explicitly requested by the analysis client.
29 ///
30 /// This works by checking querying if MBFI is available and otherwise
31 /// generating MBFI on the fly. In this case the passes required for (LI, DT)
32 /// are also queried before being computed on the fly.
33 ///
34 /// Note that it is expected that we wouldn't need this functionality for the
35 /// new PM since with the new PM, analyses are executed on demand.
36 
38 private:
39  /// If generated on the fly this own the instance.
40  mutable std::unique_ptr<MachineBlockFrequencyInfo> OwnedMBFI;
41 
42  /// If generated on the fly this own the instance.
43  mutable std::unique_ptr<MachineLoopInfo> OwnedMLI;
44 
45  /// If generated on the fly this own the instance.
46  mutable std::unique_ptr<MachineDominatorTree> OwnedMDT;
47 
48  /// The function.
49  MachineFunction *MF = nullptr;
50 
51  /// Calculate MBFI and all other analyses that's not available and
52  /// required by BFI.
53  MachineBlockFrequencyInfo &calculateIfNotAvailable() const;
54 
55 public:
56  static char ID;
57 
59 
60  /// Compute and return the block frequencies.
61  MachineBlockFrequencyInfo &getBFI() { return calculateIfNotAvailable(); }
62 
63  /// Compute and return the block frequencies.
65  return calculateIfNotAvailable();
66  }
67 
68  void getAnalysisUsage(AnalysisUsage &AU) const override;
69 
70  bool runOnMachineFunction(MachineFunction &F) override;
71  void releaseMemory() override;
72  void print(raw_ostream &OS, const Module *M) const override;
73 };
74 }
75 #endif
This class represents lattice values for constants.
Definition: AllocatorList.h:23
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:65
const MachineBlockFrequencyInfo & getBFI() const
Compute and return the block frequencies.
MachineBlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to estimate machine basic b...
F(f)
void print(raw_ostream &OS, const Module *M) const override
print - Print out the internal state of the pass.
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
MachineBlockFrequencyInfo & getBFI()
Compute and return the block frequencies.
bool runOnMachineFunction(MachineFunction &F) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - This function should be overriden by passes that need analysis information to do t...
This is an alternative analysis pass to MachineBlockFrequencyInfo.
Represent the analysis usage information of a pass.
void releaseMemory() override
releaseMemory() - This member can be implemented by a pass if it wants to be able to release its memo...
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45