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      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