clang  3.9.0
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"
21 #include "llvm/ADT/StringMap.h"
22 #include "llvm/ProfileData/InstrProfReader.h"
23 #include "llvm/Support/MemoryBuffer.h"
24 #include <array>
25 #include <memory>
26 
27 namespace clang {
28 namespace CodeGen {
29 
30 /// Per-function PGO state.
31 class CodeGenPGO {
32 private:
33  CodeGenModule &CGM;
34  std::string FuncName;
35  llvm::GlobalVariable *FuncNameVar;
36 
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;
48 
49 public:
51  : CGM(CGM), NumValueSites({{0}}), NumRegionCounters(0),
52  FunctionHash(0), CurrentRegionCount(0), SkipCoverageMapping(false) {}
53 
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
56  /// discarded.
57  bool haveRegionCounts() const { return !RegionCounts.empty(); }
58 
59  /// Return the counter value of the current region.
60  uint64_t getCurrentRegionCount() const { return CurrentRegionCount; }
61 
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
64  /// exits.
65  void setCurrentRegionCount(uint64_t Count) { CurrentRegionCount = Count; }
66 
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.
70  if (!StmtCountMap)
71  return None;
72  auto I = StmtCountMap->find(S);
73  if (I == StmtCountMap->end())
74  return None;
75  return I->second;
76  }
77 
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))
83  }
84 
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);
97 private:
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,
103  llvm::Function *Fn);
104  void loadRegionCounts(llvm::IndexedInstrProfReader *PGOReader,
105  bool IsInMainFile);
106  bool skipRegionMappingForDecl(const Decl *D);
107  void emitCounterRegionMapping(const Decl *D);
108 
109 public:
111 
112  /// Return the region count for the counter at the given index.
113  uint64_t getRegionCount(const Stmt *S) {
114  if (!RegionCounterMap)
115  return 0;
116  if (!haveRegionCounts())
117  return 0;
118  return RegionCounts[(*RegionCounterMap)[S]];
119  }
120 };
121 
122 } // end namespace CodeGen
123 } // end namespace clang
124 
125 #endif
Optional< uint64_t > getStmtCount(const Stmt *S)
Check if an execution count is known for a given statement.
Definition: CodeGenPGO.h:69
void emitCounterIncrement(CGBuilderTy &Builder, const Stmt *S)
Definition: CodeGenPGO.cpp:736
uint64_t getCurrentRegionCount() const
Return the counter value of the current region.
Definition: CodeGenPGO.h:60
Linkage
Describes the different kinds of linkage (C++ [basic.link], C99 6.2.2) that an entity may have...
Definition: Linkage.h:25
class LLVM_ALIGNAS(8) DependentTemplateSpecializationType const IdentifierInfo * Name
Represents a template specialization type whose template cannot be resolved, e.g. ...
Definition: Type.h:4549
void setCurrentRegionCount(uint64_t Count)
Set the counter value for the current region.
Definition: CodeGenPGO.h:65
void assignRegionCounters(GlobalDecl GD, llvm::Function *Fn)
Assign counters to regions and configure them for PGO of a given function.
Definition: CodeGenPGO.cpp:614
detail::InMemoryDirectory::const_iterator I
void valueProfile(CGBuilderTy &Builder, uint32_t ValueKind, llvm::Instruction *ValueSite, llvm::Value *ValuePtr)
Definition: CodeGenPGO.cpp:753
bool haveRegionCounts() const
Whether or not we have PGO region data for the current function.
Definition: CodeGenPGO.h:57
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:29
Per-function PGO state.
Definition: CodeGenPGO.h:31
This class organizes the cross-function state that is used while generating LLVM code.
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:692
void setCurrentStmt(const Stmt *S)
If the execution count for the current statement is known, record that as the current count...
Definition: CodeGenPGO.h:80
BoundNodesTreeBuilder *const Builder
uint64_t getRegionCount(const Stmt *S)
Return the region count for the counter at the given index.
Definition: CodeGenPGO.h:113
CodeGenPGO(CodeGenModule &CGM)
Definition: CodeGenPGO.h:50