clang 8.0.0

CodeGenPGO.h
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1 //===--- CodeGenPGO.h - PGO Instrumentation for LLVM CodeGen ----*- 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 //
10 // Instrumentation-based profile-guided optimization
11 //
12 //===----------------------------------------------------------------------===//
13
14 #ifndef LLVM_CLANG_LIB_CODEGEN_CODEGENPGO_H
15 #define LLVM_CLANG_LIB_CODEGEN_CODEGENPGO_H
16
17 #include "CGBuilder.h"
18 #include "CodeGenModule.h"
19 #include "CodeGenTypes.h"
20 #include "llvm/ProfileData/InstrProfReader.h"
21 #include <array>
22 #include <memory>
23
24 namespace clang {
25 namespace CodeGen {
26
27 /// Per-function PGO state.
28 class CodeGenPGO {
29 private:
30 CodeGenModule &CGM;
31 std::string FuncName;
32 llvm::GlobalVariable *FuncNameVar;
33
34 std::array <unsigned, llvm::IPVK_Last + 1> NumValueSites;
35 unsigned NumRegionCounters;
36 uint64_t FunctionHash;
37 std::unique_ptr<llvm::DenseMap<const Stmt *, unsigned>> RegionCounterMap;
38 std::unique_ptr<llvm::DenseMap<const Stmt *, uint64_t>> StmtCountMap;
39 std::unique_ptr<llvm::InstrProfRecord> ProfRecord;
40 std::vector<uint64_t> RegionCounts;
41 uint64_t CurrentRegionCount;
42
43 public:
44 CodeGenPGO(CodeGenModule &CGM)
45 : CGM(CGM), NumValueSites({{0}}), NumRegionCounters(0), FunctionHash(0),
46 CurrentRegionCount(0) {}
47
48 /// Whether or not we have PGO region data for the current function. This is
49 /// false both when we have no data at all and when our data has been
50 /// discarded.
51 bool haveRegionCounts() const { return !RegionCounts.empty(); }
52
53 /// Return the counter value of the current region.
54 uint64_t getCurrentRegionCount() const { return CurrentRegionCount; }
55
56 /// Set the counter value for the current region. This is used to keep track
57 /// of changes to the most recent counter from control flow and non-local
58 /// exits.
59 void setCurrentRegionCount(uint64_t Count) { CurrentRegionCount = Count; }
60
61 /// Check if an execution count is known for a given statement. If so, return
62 /// true and put the value in Count; else return false.
63 Optional<uint64_t> getStmtCount(const Stmt *S) {
64 if (!StmtCountMap)
65 return None;
66 auto I = StmtCountMap->find(S);
67 if (I == StmtCountMap->end())
68 return None;
69 return I->second;
70 }
71
72 /// If the execution count for the current statement is known, record that
73 /// as the current count.
74 void setCurrentStmt(const Stmt *S) {
75 if (auto Count = getStmtCount(S))
76 setCurrentRegionCount(*Count);
77 }
78
79 /// Assign counters to regions and configure them for PGO of a given
80 /// function. Does nothing if instrumentation is not enabled and either
81 /// generates global variables or associates PGO data with each of the
82 /// counters depending on whether we are generating or using instrumentation.
83 void assignRegionCounters(GlobalDecl GD, llvm::Function *Fn);
84 /// Emit a coverage mapping range with a counter zero
85 /// for an unused declaration.
86 void emitEmptyCounterMapping(const Decl *D, StringRef FuncName,
87 llvm::GlobalValue::LinkageTypes Linkage);
88 // Insert instrumentation or attach profile metadata at value sites
89 void valueProfile(CGBuilderTy &Builder, uint32_t ValueKind,
90 llvm::Instruction *ValueSite, llvm::Value *ValuePtr);
91 private:
92 void setFuncName(llvm::Function *Fn);
93 void setFuncName(StringRef Name, llvm::GlobalValue::LinkageTypes Linkage);
94 void mapRegionCounters(const Decl *D);
95 void computeRegionCounts(const Decl *D);
96 void applyFunctionAttributes(llvm::IndexedInstrProfReader *PGOReader,
97 llvm::Function *Fn);
98 void loadRegionCounts(llvm::IndexedInstrProfReader *PGOReader,
99 bool IsInMainFile);
100 bool skipRegionMappingForDecl(const Decl *D);
101 void emitCounterRegionMapping(const Decl *D);
102
103 public:
104 void emitCounterIncrement(CGBuilderTy &Builder, const Stmt *S,
105 llvm::Value *StepV);
106
107 /// Return the region count for the counter at the given index.
108 uint64_t getRegionCount(const Stmt *S) {
109 if (!RegionCounterMap)
110 return 0;
111 if (!haveRegionCounts())
112 return 0;
113 return RegionCounts[(*RegionCounterMap)[S]];
114 }
115 };
116
117 } // end namespace CodeGen
118 } // end namespace clang
119
120 #endif
clang::CodeGen::CodeGenPGO::getStmtCount
Optional< uint64_t > getStmtCount(const Stmt *S)
Check if an execution count is known for a given statement.
Definition: CodeGenPGO.h:63
clang::Stmt
Stmt - This represents one statement.
Definition: Stmt.h:66
clang::Decl
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:87
clang::CodeGen::CodeGenPGO::emitCounterIncrement
void emitCounterIncrement(CGBuilderTy &Builder, const Stmt *S, llvm::Value *StepV)
Definition: CodeGenPGO.cpp:893
Value
Value
Definition: UninitializedValues.cpp:102
clang::Linkage
Linkage
Describes the different kinds of linkage (C++ [basic.link], C99 6.2.2) that an entity may have...
Definition: Linkage.h:24
llvm::Optional
Definition: LLVM.h:38
clang::CodeGen::CodeGenPGO::setCurrentRegionCount
void setCurrentRegionCount(uint64_t Count)
Set the counter value for the current region.
Definition: CodeGenPGO.h:59
clang::CodeGen::CodeGenPGO::assignRegionCounters
void assignRegionCounters(GlobalDecl GD, llvm::Function *Fn)
Assign counters to regions and configure them for PGO of a given function.
Definition: CodeGenPGO.cpp:760
clang::CodeGen::CodeGenPGO::valueProfile
void valueProfile(CGBuilderTy &Builder, uint32_t ValueKind, llvm::Instruction *ValueSite, llvm::Value *ValuePtr)
Definition: CodeGenPGO.cpp:918
CodeGenModule.h
clang::GlobalDecl
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:35
clang::CodeGen::CodeGenPGO
Per-function PGO state.
Definition: CodeGenPGO.h:28
clang::CodeGen::CodeGenPGO::getCurrentRegionCount
uint64_t getCurrentRegionCount() const
Return the counter value of the current region.
Definition: CodeGenPGO.h:54
clang::CodeGen::CodeGenModule
This class organizes the cross-function state that is used while generating LLVM code.
Definition: CodeGenModule.h:274
clang
Dataflow Directional Tag Classes.
Definition: CFGReachabilityAnalysis.h:22
CodeGenTypes.h
clang::CodeGen::CodeGenPGO::emitEmptyCounterMapping
void emitEmptyCounterMapping(const Decl *D, StringRef FuncName, llvm::GlobalValue::LinkageTypes Linkage)
Emit a coverage mapping range with a counter zero for an unused declaration.
Definition: CodeGenPGO.cpp:849
clang::CodeGen::CodeGenPGO::setCurrentStmt
void setCurrentStmt(const Stmt *S)
If the execution count for the current statement is known, record that as the current count...
Definition: CodeGenPGO.h:74
clang::CodeGen::CodeGenPGO::getRegionCount
uint64_t getRegionCount(const Stmt *S)
Return the region count for the counter at the given index.
Definition: CodeGenPGO.h:108
CGBuilder.h
clang::CodeGen::CGBuilderTy
Definition: CGBuilder.h:45
clang::CodeGen::CodeGenPGO::haveRegionCounts
bool haveRegionCounts() const
Whether or not we have PGO region data for the current function.
Definition: CodeGenPGO.h:51
clang::CodeGen::CodeGenPGO::CodeGenPGO
CodeGenPGO(CodeGenModule &CGM)
Definition: CodeGenPGO.h:44