1 //===--- CodeGenPGO.h - PGO Instrumentation for LLVM CodeGen ----*- 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 // Instrumentation-based profile-guided optimization
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_CLANG_LIB_CODEGEN_CODEGENPGO_H
15 #define LLVM_CLANG_LIB_CODEGEN_CODEGENPGO_H
17 #include "CGBuilder.h"
18 #include "CodeGenModule.h"
19 #include "CodeGenTypes.h"
20 #include "clang/Frontend/CodeGenOptions.h"
21 #include "llvm/ADT/StringMap.h"
22 #include "llvm/ProfileData/InstrProfReader.h"
23 #include "llvm/Support/MemoryBuffer.h"
30 /// Per-function PGO state.
35 llvm::GlobalVariable *FuncNameVar;
37 std::array <unsigned, llvm::IPVK_Last + 1> NumValueSites;
38 unsigned NumRegionCounters;
39 uint64_t FunctionHash;
40 std::unique_ptr<llvm::DenseMap<const Stmt *, unsigned>> RegionCounterMap;
41 std::unique_ptr<llvm::DenseMap<const Stmt *, uint64_t>> StmtCountMap;
42 std::unique_ptr<llvm::InstrProfRecord> ProfRecord;
43 std::vector<uint64_t> RegionCounts;
44 uint64_t CurrentRegionCount;
45 /// \brief A flag that is set to true when this function doesn't need
46 /// to have coverage mapping data.
47 bool SkipCoverageMapping;
50 CodeGenPGO(CodeGenModule &CGM)
51 : CGM(CGM), NumValueSites({{0}}), NumRegionCounters(0),
52 FunctionHash(0), CurrentRegionCount(0), SkipCoverageMapping(false) {}
54 /// Whether or not we have PGO region data for the current function. This is
55 /// false both when we have no data at all and when our data has been
57 bool haveRegionCounts() const { return !RegionCounts.empty(); }
59 /// Return the counter value of the current region.
60 uint64_t getCurrentRegionCount() const { return CurrentRegionCount; }
62 /// Set the counter value for the current region. This is used to keep track
63 /// of changes to the most recent counter from control flow and non-local
65 void setCurrentRegionCount(uint64_t Count) { CurrentRegionCount = Count; }
67 /// Check if an execution count is known for a given statement. If so, return
68 /// true and put the value in Count; else return false.
69 Optional<uint64_t> getStmtCount(const Stmt *S) {
72 auto I = StmtCountMap->find(S);
73 if (I == StmtCountMap->end())
78 /// If the execution count for the current statement is known, record that
79 /// as the current count.
80 void setCurrentStmt(const Stmt *S) {
81 if (auto Count = getStmtCount(S))
82 setCurrentRegionCount(*Count);
85 /// Assign counters to regions and configure them for PGO of a given
86 /// function. Does nothing if instrumentation is not enabled and either
87 /// generates global variables or associates PGO data with each of the
88 /// counters depending on whether we are generating or using instrumentation.
89 void assignRegionCounters(GlobalDecl GD, llvm::Function *Fn);
90 /// Emit a coverage mapping range with a counter zero
91 /// for an unused declaration.
92 void emitEmptyCounterMapping(const Decl *D, StringRef FuncName,
93 llvm::GlobalValue::LinkageTypes Linkage);
94 // Insert instrumentation or attach profile metadata at value sites
95 void valueProfile(CGBuilderTy &Builder, uint32_t ValueKind,
96 llvm::Instruction *ValueSite, llvm::Value *ValuePtr);
98 void setFuncName(llvm::Function *Fn);
99 void setFuncName(StringRef Name, llvm::GlobalValue::LinkageTypes Linkage);
100 void mapRegionCounters(const Decl *D);
101 void computeRegionCounts(const Decl *D);
102 void applyFunctionAttributes(llvm::IndexedInstrProfReader *PGOReader,
104 void loadRegionCounts(llvm::IndexedInstrProfReader *PGOReader,
106 bool skipRegionMappingForDecl(const Decl *D);
107 void emitCounterRegionMapping(const Decl *D);
110 void emitCounterIncrement(CGBuilderTy &Builder, const Stmt *S);
112 /// Return the region count for the counter at the given index.
113 uint64_t getRegionCount(const Stmt *S) {
114 if (!RegionCounterMap)
116 if (!haveRegionCounts())
118 return RegionCounts[(*RegionCounterMap)[S]];
122 } // end namespace CodeGen
123 } // end namespace clang