1 //===- Transforms/Instrumentation/InstrProfiling.h --------------*- 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 file provides the interface for LLVM's PGO Instrumentation lowering
10 /// pass.
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_TRANSFORMS_INSTRUMENTATION_INSTRPROFILING_H
14 #define LLVM_TRANSFORMS_INSTRUMENTATION_INSTRPROFILING_H
15 
16 #include "llvm/ADT/DenseMap.h"
17 #include "llvm/ADT/StringRef.h"
18 #include "llvm/IR/IntrinsicInst.h"
19 #include "llvm/IR/PassManager.h"
20 #include "llvm/ProfileData/InstrProf.h"
21 #include "llvm/Transforms/Instrumentation.h"
22 #include <cstddef>
23 #include <cstdint>
24 #include <cstring>
25 #include <vector>
26 
27 namespace llvm {
28 
29 class TargetLibraryInfo;
30 using LoadStorePair = std::pair<Instruction *, Instruction *>;
31 
32 /// Instrumentation based profiling lowering pass. This pass lowers
33 /// the profile instrumented code generated by FE or the IR based
34 /// instrumentation pass.
35 class InstrProfiling : public PassInfoMixin<InstrProfiling> {
36 public:
37   InstrProfiling() : IsCS(false) {}
38   InstrProfiling(const InstrProfOptions &Options, bool IsCS = false)
39       : Options(Options), IsCS(IsCS) {}
40 
41   PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
42   bool run(Module &M,
43            std::function<const TargetLibraryInfo &(Function &F)> GetTLI);
44 
45 private:
46   InstrProfOptions Options;
47   Module *M;
48   Triple TT;
49   std::function<const TargetLibraryInfo &(Function &F)> GetTLI;
50   struct PerFunctionProfileData {
51     uint32_t NumValueSites[IPVK_Last + 1];
52     GlobalVariable *RegionCounters = nullptr;
53     GlobalVariable *DataVar = nullptr;
54 
55     PerFunctionProfileData() {
56       memset(NumValueSites, 0, sizeof(uint32_t) * (IPVK_Last + 1));
57     }
58   };
59   DenseMap<GlobalVariable *, PerFunctionProfileData> ProfileDataMap;
60   std::vector<GlobalValue *> CompilerUsedVars;
61   std::vector<GlobalValue *> UsedVars;
62   std::vector<GlobalVariable *> ReferencedNames;
63   GlobalVariable *NamesVar;
64   size_t NamesSize;
65 
66   // Is this lowering for the context-sensitive instrumentation.
67   bool IsCS;
68 
69   // vector of counter load/store pairs to be register promoted.
70   std::vector<LoadStorePair> PromotionCandidates;
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 relocating counters at runtime is enabled.
82   bool isRuntimeCounterRelocationEnabled() const;
83 
84   /// Returns true if profile counter update register promotion is enabled.
85   bool isCounterPromotionEnabled() const;
86 
87   /// Count the number of instrumented value sites for the function.
88   void computeNumValueSiteCounts(InstrProfValueProfileInst *Ins);
89 
90   /// Replace instrprof_value_profile with a call to runtime library.
91   void lowerValueProfileInst(InstrProfValueProfileInst *Ins);
92 
93   /// Replace instrprof_increment with an increment of the appropriate value.
94   void lowerIncrement(InstrProfIncrementInst *Inc);
95 
96   /// Force emitting of name vars for unused functions.
97   void lowerCoverageData(GlobalVariable *CoverageNamesVar);
98 
99   /// Get the region counters for an increment, creating them if necessary.
100   ///
101   /// If the counter array doesn't yet exist, the profile data variables
102   /// referring to them will also be created.
103   GlobalVariable *getOrCreateRegionCounters(InstrProfIncrementInst *Inc);
104 
105   /// Emit the section with compressed function names.
106   void emitNameData();
107 
108   /// Emit value nodes section for value profiling.
109   void emitVNodes();
110 
111   /// Emit runtime registration functions for each profile data variable.
112   void emitRegistration();
113 
114   /// Emit the necessary plumbing to pull in the runtime initialization.
115   /// Returns true if a change was made.
116   bool emitRuntimeHook();
117 
118   /// Add uses of our data variables and runtime hook.
119   void emitUses();
120 
121   /// Create a static initializer for our data, on platforms that need it,
122   /// and for any profile output file that was specified.
123   void emitInitialization();
124 };
125 
126 } // end namespace llvm
127 
128 #endif // LLVM_TRANSFORMS_INSTRUMENTATION_INSTRPROFILING_H
129