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/ProfileData/InstrProfReader.h"
28 /// Per-function PGO state.
33 llvm::GlobalVariable *FuncNameVar;
35 std::array <unsigned, llvm::IPVK_Last + 1> NumValueSites;
36 unsigned NumRegionCounters;
37 uint64_t FunctionHash;
38 std::unique_ptr<llvm::DenseMap<const Stmt *, unsigned>> RegionCounterMap;
39 std::unique_ptr<llvm::DenseMap<const Stmt *, uint64_t>> StmtCountMap;
40 std::unique_ptr<llvm::InstrProfRecord> ProfRecord;
41 std::vector<uint64_t> RegionCounts;
42 uint64_t CurrentRegionCount;
43 /// \brief A flag that is set to true when this function doesn't need
44 /// to have coverage mapping data.
45 bool SkipCoverageMapping;
48 CodeGenPGO(CodeGenModule &CGM)
49 : CGM(CGM), NumValueSites({{0}}), NumRegionCounters(0),
50 FunctionHash(0), CurrentRegionCount(0), SkipCoverageMapping(false) {}
52 /// Whether or not we have PGO region data for the current function. This is
53 /// false both when we have no data at all and when our data has been
55 bool haveRegionCounts() const { return !RegionCounts.empty(); }
57 /// Return the counter value of the current region.
58 uint64_t getCurrentRegionCount() const { return CurrentRegionCount; }
60 /// Set the counter value for the current region. This is used to keep track
61 /// of changes to the most recent counter from control flow and non-local
63 void setCurrentRegionCount(uint64_t Count) { CurrentRegionCount = Count; }
65 /// Check if an execution count is known for a given statement. If so, return
66 /// true and put the value in Count; else return false.
67 Optional<uint64_t> getStmtCount(const Stmt *S) {
70 auto I = StmtCountMap->find(S);
71 if (I == StmtCountMap->end())
76 /// If the execution count for the current statement is known, record that
77 /// as the current count.
78 void setCurrentStmt(const Stmt *S) {
79 if (auto Count = getStmtCount(S))
80 setCurrentRegionCount(*Count);
83 /// Assign counters to regions and configure them for PGO of a given
84 /// function. Does nothing if instrumentation is not enabled and either
85 /// generates global variables or associates PGO data with each of the
86 /// counters depending on whether we are generating or using instrumentation.
87 void assignRegionCounters(GlobalDecl GD, llvm::Function *Fn);
88 /// Emit a coverage mapping range with a counter zero
89 /// for an unused declaration.
90 void emitEmptyCounterMapping(const Decl *D, StringRef FuncName,
91 llvm::GlobalValue::LinkageTypes Linkage);
92 // Insert instrumentation or attach profile metadata at value sites
93 void valueProfile(CGBuilderTy &Builder, uint32_t ValueKind,
94 llvm::Instruction *ValueSite, llvm::Value *ValuePtr);
96 void setFuncName(llvm::Function *Fn);
97 void setFuncName(StringRef Name, llvm::GlobalValue::LinkageTypes Linkage);
98 void mapRegionCounters(const Decl *D);
99 void computeRegionCounts(const Decl *D);
100 void applyFunctionAttributes(llvm::IndexedInstrProfReader *PGOReader,
102 void loadRegionCounts(llvm::IndexedInstrProfReader *PGOReader,
104 bool skipRegionMappingForDecl(const Decl *D);
105 void emitCounterRegionMapping(const Decl *D);
108 void emitCounterIncrement(CGBuilderTy &Builder, const Stmt *S,
111 /// Return the region count for the counter at the given index.
112 uint64_t getRegionCount(const Stmt *S) {
113 if (!RegionCounterMap)
115 if (!haveRegionCounts())
117 return RegionCounts[(*RegionCounterMap)[S]];
121 } // end namespace CodeGen
122 } // end namespace clang