1 //===- Transforms/Instrumentation/InstrProfiling.h --------------*- 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 /// \file
10 /// This file provides the interface for LLVM's PGO Instrumentation lowering
11 /// pass.
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_TRANSFORMS_INSTRPROFILING_H
15 #define LLVM_TRANSFORMS_INSTRPROFILING_H
16 
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/IR/IntrinsicInst.h"
20 #include "llvm/IR/PassManager.h"
21 #include "llvm/ProfileData/InstrProf.h"
22 #include "llvm/Transforms/Instrumentation.h"
23 #include <cstddef>
24 #include <cstdint>
25 #include <cstring>
26 #include <vector>
27 
28 namespace llvm {
29 
30 class TargetLibraryInfo;
31 using LoadStorePair = std::pair<Instruction *, Instruction *>;
32 
33 /// Instrumentation based profiling lowering pass. This pass lowers
34 /// the profile instrumented code generated by FE or the IR based
35 /// instrumentation pass.
36 class InstrProfiling : public PassInfoMixin<InstrProfiling> {
37 public:
38   InstrProfiling() = default;
InstrProfiling(const InstrProfOptions & Options)39   InstrProfiling(const InstrProfOptions &Options) : Options(Options) {}
40 
41   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
42   bool run(Module &M, const TargetLibraryInfo &TLI);
43 
44 private:
45   InstrProfOptions Options;
46   Module *M;
47   Triple TT;
48   const TargetLibraryInfo *TLI;
49   struct PerFunctionProfileData {
50     uint32_t NumValueSites[IPVK_Last + 1];
51     GlobalVariable *RegionCounters = nullptr;
52     GlobalVariable *DataVar = nullptr;
53 
PerFunctionProfileDataPerFunctionProfileData54     PerFunctionProfileData() {
55       memset(NumValueSites, 0, sizeof(uint32_t) * (IPVK_Last + 1));
56     }
57   };
58   DenseMap<GlobalVariable *, PerFunctionProfileData> ProfileDataMap;
59   std::vector<GlobalValue *> UsedVars;
60   std::vector<GlobalVariable *> ReferencedNames;
61   GlobalVariable *NamesVar;
62   size_t NamesSize;
63 
64   // vector of counter load/store pairs to be register promoted.
65   std::vector<LoadStorePair> PromotionCandidates;
66 
67   // The start value of precise value profile range for memory intrinsic sizes.
68   int64_t MemOPSizeRangeStart;
69   // The end value of precise value profile range for memory intrinsic sizes.
70   int64_t MemOPSizeRangeLast;
71 
72   int64_t TotalCountersPromoted = 0;
73 
74   /// Lower instrumentation intrinsics in the function. Returns true if there
75   /// any lowering.
76   bool lowerIntrinsics(Function *F);
77 
78   /// Register-promote counter loads and stores in loops.
79   void promoteCounterLoadStores(Function *F);
80 
81   /// Returns true if profile counter update register promotion is enabled.
82   bool isCounterPromotionEnabled() const;
83 
84   /// Count the number of instrumented value sites for the function.
85   void computeNumValueSiteCounts(InstrProfValueProfileInst *Ins);
86 
87   /// Replace instrprof_value_profile with a call to runtime library.
88   void lowerValueProfileInst(InstrProfValueProfileInst *Ins);
89 
90   /// Replace instrprof_increment with an increment of the appropriate value.
91   void lowerIncrement(InstrProfIncrementInst *Inc);
92 
93   /// Force emitting of name vars for unused functions.
94   void lowerCoverageData(GlobalVariable *CoverageNamesVar);
95 
96   /// Get the region counters for an increment, creating them if necessary.
97   ///
98   /// If the counter array doesn't yet exist, the profile data variables
99   /// referring to them will also be created.
100   GlobalVariable *getOrCreateRegionCounters(InstrProfIncrementInst *Inc);
101 
102   /// Emit the section with compressed function names.
103   void emitNameData();
104 
105   /// Emit value nodes section for value profiling.
106   void emitVNodes();
107 
108   /// Emit runtime registration functions for each profile data variable.
109   void emitRegistration();
110 
111   /// Emit the necessary plumbing to pull in the runtime initialization.
112   /// Returns true if a change was made.
113   bool emitRuntimeHook();
114 
115   /// Add uses of our data variables and runtime hook.
116   void emitUses();
117 
118   /// Create a static initializer for our data, on platforms that need it,
119   /// and for any profile output file that was specified.
120   void emitInitialization();
121 };
122 
123 } // end namespace llvm
124 
125 #endif // LLVM_TRANSFORMS_INSTRPROFILING_H
126