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      1 //=-- CoverageMapping.h - Code coverage mapping support ---------*- 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 // Code coverage mapping data is generated by clang and read by
     11 // llvm-cov to show code coverage statistics for a file.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #ifndef LLVM_PROFILEDATA_COVERAGEMAPPING_H_
     16 #define LLVM_PROFILEDATA_COVERAGEMAPPING_H_
     17 
     18 #include "llvm/ADT/ArrayRef.h"
     19 #include "llvm/ADT/DenseMap.h"
     20 #include "llvm/ADT/Hashing.h"
     21 #include "llvm/ADT/Triple.h"
     22 #include "llvm/ADT/iterator.h"
     23 #include "llvm/ProfileData/InstrProf.h"
     24 #include "llvm/Support/Debug.h"
     25 #include "llvm/Support/Endian.h"
     26 #include "llvm/Support/raw_ostream.h"
     27 #include <system_error>
     28 #include <tuple>
     29 
     30 namespace llvm {
     31 namespace coverage {
     32 
     33 enum class coveragemap_error {
     34   success = 0,
     35   eof,
     36   no_data_found,
     37   unsupported_version,
     38   truncated,
     39   malformed
     40 };
     41 
     42 const std::error_category &coveragemap_category();
     43 
     44 inline std::error_code make_error_code(coveragemap_error E) {
     45   return std::error_code(static_cast<int>(E), coveragemap_category());
     46 }
     47 
     48 class CoverageMapError : public ErrorInfo<CoverageMapError> {
     49 public:
     50   CoverageMapError(coveragemap_error Err) : Err(Err) {
     51     assert(Err != coveragemap_error::success && "Not an error");
     52   }
     53 
     54   std::string message() const override;
     55 
     56   void log(raw_ostream &OS) const override { OS << message(); }
     57 
     58   std::error_code convertToErrorCode() const override {
     59     return make_error_code(Err);
     60   }
     61 
     62   coveragemap_error get() const { return Err; }
     63 
     64   static char ID;
     65 
     66 private:
     67   coveragemap_error Err;
     68 };
     69 
     70 } // end of coverage namespace.
     71 } // end of llvm namespace
     72 
     73 namespace llvm {
     74 class IndexedInstrProfReader;
     75 namespace coverage {
     76 
     77 class CoverageMappingReader;
     78 
     79 class CoverageMapping;
     80 struct CounterExpressions;
     81 
     82 /// \brief A Counter is an abstract value that describes how to compute the
     83 /// execution count for a region of code using the collected profile count data.
     84 struct Counter {
     85   enum CounterKind { Zero, CounterValueReference, Expression };
     86   static const unsigned EncodingTagBits = 2;
     87   static const unsigned EncodingTagMask = 0x3;
     88   static const unsigned EncodingCounterTagAndExpansionRegionTagBits =
     89       EncodingTagBits + 1;
     90 
     91 private:
     92   CounterKind Kind;
     93   unsigned ID;
     94 
     95   Counter(CounterKind Kind, unsigned ID) : Kind(Kind), ID(ID) {}
     96 
     97 public:
     98   Counter() : Kind(Zero), ID(0) {}
     99 
    100   CounterKind getKind() const { return Kind; }
    101 
    102   bool isZero() const { return Kind == Zero; }
    103 
    104   bool isExpression() const { return Kind == Expression; }
    105 
    106   unsigned getCounterID() const { return ID; }
    107 
    108   unsigned getExpressionID() const { return ID; }
    109 
    110   friend bool operator==(const Counter &LHS, const Counter &RHS) {
    111     return LHS.Kind == RHS.Kind && LHS.ID == RHS.ID;
    112   }
    113 
    114   friend bool operator!=(const Counter &LHS, const Counter &RHS) {
    115     return !(LHS == RHS);
    116   }
    117 
    118   friend bool operator<(const Counter &LHS, const Counter &RHS) {
    119     return std::tie(LHS.Kind, LHS.ID) < std::tie(RHS.Kind, RHS.ID);
    120   }
    121 
    122   /// \brief Return the counter that represents the number zero.
    123   static Counter getZero() { return Counter(); }
    124 
    125   /// \brief Return the counter that corresponds to a specific profile counter.
    126   static Counter getCounter(unsigned CounterId) {
    127     return Counter(CounterValueReference, CounterId);
    128   }
    129 
    130   /// \brief Return the counter that corresponds to a specific
    131   /// addition counter expression.
    132   static Counter getExpression(unsigned ExpressionId) {
    133     return Counter(Expression, ExpressionId);
    134   }
    135 };
    136 
    137 /// \brief A Counter expression is a value that represents an arithmetic
    138 /// operation with two counters.
    139 struct CounterExpression {
    140   enum ExprKind { Subtract, Add };
    141   ExprKind Kind;
    142   Counter LHS, RHS;
    143 
    144   CounterExpression(ExprKind Kind, Counter LHS, Counter RHS)
    145       : Kind(Kind), LHS(LHS), RHS(RHS) {}
    146 };
    147 
    148 /// \brief A Counter expression builder is used to construct the
    149 /// counter expressions. It avoids unnecessary duplication
    150 /// and simplifies algebraic expressions.
    151 class CounterExpressionBuilder {
    152   /// \brief A list of all the counter expressions
    153   std::vector<CounterExpression> Expressions;
    154   /// \brief A lookup table for the index of a given expression.
    155   llvm::DenseMap<CounterExpression, unsigned> ExpressionIndices;
    156 
    157   /// \brief Return the counter which corresponds to the given expression.
    158   ///
    159   /// If the given expression is already stored in the builder, a counter
    160   /// that references that expression is returned. Otherwise, the given
    161   /// expression is added to the builder's collection of expressions.
    162   Counter get(const CounterExpression &E);
    163 
    164   /// \brief Gather the terms of the expression tree for processing.
    165   ///
    166   /// This collects each addition and subtraction referenced by the counter into
    167   /// a sequence that can be sorted and combined to build a simplified counter
    168   /// expression.
    169   void extractTerms(Counter C, int Sign,
    170                     SmallVectorImpl<std::pair<unsigned, int>> &Terms);
    171 
    172   /// \brief Simplifies the given expression tree
    173   /// by getting rid of algebraically redundant operations.
    174   Counter simplify(Counter ExpressionTree);
    175 
    176 public:
    177   ArrayRef<CounterExpression> getExpressions() const { return Expressions; }
    178 
    179   /// \brief Return a counter that represents the expression
    180   /// that adds LHS and RHS.
    181   Counter add(Counter LHS, Counter RHS);
    182 
    183   /// \brief Return a counter that represents the expression
    184   /// that subtracts RHS from LHS.
    185   Counter subtract(Counter LHS, Counter RHS);
    186 };
    187 
    188 /// \brief A Counter mapping region associates a source range with
    189 /// a specific counter.
    190 struct CounterMappingRegion {
    191   enum RegionKind {
    192     /// \brief A CodeRegion associates some code with a counter
    193     CodeRegion,
    194 
    195     /// \brief An ExpansionRegion represents a file expansion region that
    196     /// associates a source range with the expansion of a virtual source file,
    197     /// such as for a macro instantiation or #include file.
    198     ExpansionRegion,
    199 
    200     /// \brief A SkippedRegion represents a source range with code that
    201     /// was skipped by a preprocessor or similar means.
    202     SkippedRegion
    203   };
    204 
    205   Counter Count;
    206   unsigned FileID, ExpandedFileID;
    207   unsigned LineStart, ColumnStart, LineEnd, ColumnEnd;
    208   RegionKind Kind;
    209 
    210   CounterMappingRegion(Counter Count, unsigned FileID, unsigned ExpandedFileID,
    211                        unsigned LineStart, unsigned ColumnStart,
    212                        unsigned LineEnd, unsigned ColumnEnd, RegionKind Kind)
    213       : Count(Count), FileID(FileID), ExpandedFileID(ExpandedFileID),
    214         LineStart(LineStart), ColumnStart(ColumnStart), LineEnd(LineEnd),
    215         ColumnEnd(ColumnEnd), Kind(Kind) {}
    216 
    217   static CounterMappingRegion
    218   makeRegion(Counter Count, unsigned FileID, unsigned LineStart,
    219              unsigned ColumnStart, unsigned LineEnd, unsigned ColumnEnd) {
    220     return CounterMappingRegion(Count, FileID, 0, LineStart, ColumnStart,
    221                                 LineEnd, ColumnEnd, CodeRegion);
    222   }
    223 
    224   static CounterMappingRegion
    225   makeExpansion(unsigned FileID, unsigned ExpandedFileID, unsigned LineStart,
    226                 unsigned ColumnStart, unsigned LineEnd, unsigned ColumnEnd) {
    227     return CounterMappingRegion(Counter(), FileID, ExpandedFileID, LineStart,
    228                                 ColumnStart, LineEnd, ColumnEnd,
    229                                 ExpansionRegion);
    230   }
    231 
    232   static CounterMappingRegion
    233   makeSkipped(unsigned FileID, unsigned LineStart, unsigned ColumnStart,
    234               unsigned LineEnd, unsigned ColumnEnd) {
    235     return CounterMappingRegion(Counter(), FileID, 0, LineStart, ColumnStart,
    236                                 LineEnd, ColumnEnd, SkippedRegion);
    237   }
    238 
    239 
    240   inline std::pair<unsigned, unsigned> startLoc() const {
    241     return std::pair<unsigned, unsigned>(LineStart, ColumnStart);
    242   }
    243 
    244   inline std::pair<unsigned, unsigned> endLoc() const {
    245     return std::pair<unsigned, unsigned>(LineEnd, ColumnEnd);
    246   }
    247 
    248   bool operator<(const CounterMappingRegion &Other) const {
    249     if (FileID != Other.FileID)
    250       return FileID < Other.FileID;
    251     return startLoc() < Other.startLoc();
    252   }
    253 
    254   bool contains(const CounterMappingRegion &Other) const {
    255     if (FileID != Other.FileID)
    256       return false;
    257     if (startLoc() > Other.startLoc())
    258       return false;
    259     if (endLoc() < Other.endLoc())
    260       return false;
    261     return true;
    262   }
    263 };
    264 
    265 /// \brief Associates a source range with an execution count.
    266 struct CountedRegion : public CounterMappingRegion {
    267   uint64_t ExecutionCount;
    268 
    269   CountedRegion(const CounterMappingRegion &R, uint64_t ExecutionCount)
    270       : CounterMappingRegion(R), ExecutionCount(ExecutionCount) {}
    271 };
    272 
    273 /// \brief A Counter mapping context is used to connect the counters,
    274 /// expressions and the obtained counter values.
    275 class CounterMappingContext {
    276   ArrayRef<CounterExpression> Expressions;
    277   ArrayRef<uint64_t> CounterValues;
    278 
    279 public:
    280   CounterMappingContext(ArrayRef<CounterExpression> Expressions,
    281                         ArrayRef<uint64_t> CounterValues = None)
    282       : Expressions(Expressions), CounterValues(CounterValues) {}
    283 
    284   void setCounts(ArrayRef<uint64_t> Counts) { CounterValues = Counts; }
    285 
    286   void dump(const Counter &C, llvm::raw_ostream &OS) const;
    287   void dump(const Counter &C) const { dump(C, dbgs()); }
    288 
    289   /// \brief Return the number of times that a region of code associated with
    290   /// this counter was executed.
    291   Expected<int64_t> evaluate(const Counter &C) const;
    292 };
    293 
    294 /// \brief Code coverage information for a single function.
    295 struct FunctionRecord {
    296   /// \brief Raw function name.
    297   std::string Name;
    298   /// \brief Associated files.
    299   std::vector<std::string> Filenames;
    300   /// \brief Regions in the function along with their counts.
    301   std::vector<CountedRegion> CountedRegions;
    302   /// \brief The number of times this function was executed.
    303   uint64_t ExecutionCount;
    304 
    305   FunctionRecord(StringRef Name, ArrayRef<StringRef> Filenames)
    306       : Name(Name), Filenames(Filenames.begin(), Filenames.end()) {}
    307 
    308   void pushRegion(CounterMappingRegion Region, uint64_t Count) {
    309     if (CountedRegions.empty())
    310       ExecutionCount = Count;
    311     CountedRegions.emplace_back(Region, Count);
    312   }
    313 };
    314 
    315 /// \brief Iterator over Functions, optionally filtered to a single file.
    316 class FunctionRecordIterator
    317     : public iterator_facade_base<FunctionRecordIterator,
    318                                   std::forward_iterator_tag, FunctionRecord> {
    319   ArrayRef<FunctionRecord> Records;
    320   ArrayRef<FunctionRecord>::iterator Current;
    321   StringRef Filename;
    322 
    323   /// \brief Skip records whose primary file is not \c Filename.
    324   void skipOtherFiles();
    325 
    326 public:
    327   FunctionRecordIterator(ArrayRef<FunctionRecord> Records_,
    328                          StringRef Filename = "")
    329       : Records(Records_), Current(Records.begin()), Filename(Filename) {
    330     skipOtherFiles();
    331   }
    332 
    333   FunctionRecordIterator() : Current(Records.begin()) {}
    334 
    335   bool operator==(const FunctionRecordIterator &RHS) const {
    336     return Current == RHS.Current && Filename == RHS.Filename;
    337   }
    338 
    339   const FunctionRecord &operator*() const { return *Current; }
    340 
    341   FunctionRecordIterator &operator++() {
    342     assert(Current != Records.end() && "incremented past end");
    343     ++Current;
    344     skipOtherFiles();
    345     return *this;
    346   }
    347 };
    348 
    349 /// \brief Coverage information for a macro expansion or #included file.
    350 ///
    351 /// When covered code has pieces that can be expanded for more detail, such as a
    352 /// preprocessor macro use and its definition, these are represented as
    353 /// expansions whose coverage can be looked up independently.
    354 struct ExpansionRecord {
    355   /// \brief The abstract file this expansion covers.
    356   unsigned FileID;
    357   /// \brief The region that expands to this record.
    358   const CountedRegion &Region;
    359   /// \brief Coverage for the expansion.
    360   const FunctionRecord &Function;
    361 
    362   ExpansionRecord(const CountedRegion &Region,
    363                   const FunctionRecord &Function)
    364       : FileID(Region.ExpandedFileID), Region(Region), Function(Function) {}
    365 };
    366 
    367 /// \brief The execution count information starting at a point in a file.
    368 ///
    369 /// A sequence of CoverageSegments gives execution counts for a file in format
    370 /// that's simple to iterate through for processing.
    371 struct CoverageSegment {
    372   /// \brief The line where this segment begins.
    373   unsigned Line;
    374   /// \brief The column where this segment begins.
    375   unsigned Col;
    376   /// \brief The execution count, or zero if no count was recorded.
    377   uint64_t Count;
    378   /// \brief When false, the segment was uninstrumented or skipped.
    379   bool HasCount;
    380   /// \brief Whether this enters a new region or returns to a previous count.
    381   bool IsRegionEntry;
    382 
    383   CoverageSegment(unsigned Line, unsigned Col, bool IsRegionEntry)
    384       : Line(Line), Col(Col), Count(0), HasCount(false),
    385         IsRegionEntry(IsRegionEntry) {}
    386 
    387   CoverageSegment(unsigned Line, unsigned Col, uint64_t Count,
    388                   bool IsRegionEntry)
    389       : Line(Line), Col(Col), Count(Count), HasCount(true),
    390         IsRegionEntry(IsRegionEntry) {}
    391 
    392   friend bool operator==(const CoverageSegment &L, const CoverageSegment &R) {
    393     return std::tie(L.Line, L.Col, L.Count, L.HasCount, L.IsRegionEntry) ==
    394            std::tie(R.Line, R.Col, R.Count, R.HasCount, R.IsRegionEntry);
    395   }
    396 };
    397 
    398 /// \brief Coverage information to be processed or displayed.
    399 ///
    400 /// This represents the coverage of an entire file, expansion, or function. It
    401 /// provides a sequence of CoverageSegments to iterate through, as well as the
    402 /// list of expansions that can be further processed.
    403 class CoverageData {
    404   std::string Filename;
    405   std::vector<CoverageSegment> Segments;
    406   std::vector<ExpansionRecord> Expansions;
    407   friend class CoverageMapping;
    408 
    409 public:
    410   CoverageData() {}
    411 
    412   CoverageData(StringRef Filename) : Filename(Filename) {}
    413 
    414   CoverageData(CoverageData &&RHS)
    415       : Filename(std::move(RHS.Filename)), Segments(std::move(RHS.Segments)),
    416         Expansions(std::move(RHS.Expansions)) {}
    417 
    418   /// \brief Get the name of the file this data covers.
    419   StringRef getFilename() const { return Filename; }
    420 
    421   std::vector<CoverageSegment>::iterator begin() { return Segments.begin(); }
    422   std::vector<CoverageSegment>::iterator end() { return Segments.end(); }
    423   bool empty() { return Segments.empty(); }
    424 
    425   /// \brief Expansions that can be further processed.
    426   ArrayRef<ExpansionRecord> getExpansions() { return Expansions; }
    427 };
    428 
    429 /// \brief The mapping of profile information to coverage data.
    430 ///
    431 /// This is the main interface to get coverage information, using a profile to
    432 /// fill out execution counts.
    433 class CoverageMapping {
    434   std::vector<FunctionRecord> Functions;
    435   unsigned MismatchedFunctionCount;
    436 
    437   CoverageMapping() : MismatchedFunctionCount(0) {}
    438 
    439 public:
    440   /// \brief Load the coverage mapping using the given readers.
    441   static Expected<std::unique_ptr<CoverageMapping>>
    442   load(CoverageMappingReader &CoverageReader,
    443        IndexedInstrProfReader &ProfileReader);
    444 
    445   /// \brief Load the coverage mapping from the given files.
    446   static Expected<std::unique_ptr<CoverageMapping>>
    447   load(StringRef ObjectFilename, StringRef ProfileFilename,
    448        StringRef Arch = StringRef());
    449 
    450   /// \brief The number of functions that couldn't have their profiles mapped.
    451   ///
    452   /// This is a count of functions whose profile is out of date or otherwise
    453   /// can't be associated with any coverage information.
    454   unsigned getMismatchedCount() { return MismatchedFunctionCount; }
    455 
    456   /// \brief Returns the list of files that are covered.
    457   std::vector<StringRef> getUniqueSourceFiles() const;
    458 
    459   /// \brief Get the coverage for a particular file.
    460   ///
    461   /// The given filename must be the name as recorded in the coverage
    462   /// information. That is, only names returned from getUniqueSourceFiles will
    463   /// yield a result.
    464   CoverageData getCoverageForFile(StringRef Filename) const;
    465 
    466   /// \brief Gets all of the functions covered by this profile.
    467   iterator_range<FunctionRecordIterator> getCoveredFunctions() const {
    468     return make_range(FunctionRecordIterator(Functions),
    469                       FunctionRecordIterator());
    470   }
    471 
    472   /// \brief Gets all of the functions in a particular file.
    473   iterator_range<FunctionRecordIterator>
    474   getCoveredFunctions(StringRef Filename) const {
    475     return make_range(FunctionRecordIterator(Functions, Filename),
    476                       FunctionRecordIterator());
    477   }
    478 
    479   /// \brief Get the list of function instantiations in the file.
    480   ///
    481   /// Functions that are instantiated more than once, such as C++ template
    482   /// specializations, have distinct coverage records for each instantiation.
    483   std::vector<const FunctionRecord *> getInstantiations(StringRef Filename);
    484 
    485   /// \brief Get the coverage for a particular function.
    486   CoverageData getCoverageForFunction(const FunctionRecord &Function);
    487 
    488   /// \brief Get the coverage for an expansion within a coverage set.
    489   CoverageData getCoverageForExpansion(const ExpansionRecord &Expansion);
    490 };
    491 
    492 // Profile coverage map has the following layout:
    493 // [CoverageMapFileHeader]
    494 // [ArrayStart]
    495 //  [CovMapFunctionRecord]
    496 //  [CovMapFunctionRecord]
    497 //  ...
    498 // [ArrayEnd]
    499 // [Encoded Region Mapping Data]
    500 LLVM_PACKED_START
    501 template <class IntPtrT> struct CovMapFunctionRecordV1 {
    502 #define COVMAP_V1
    503 #define COVMAP_FUNC_RECORD(Type, LLVMType, Name, Init) Type Name;
    504 #include "llvm/ProfileData/InstrProfData.inc"
    505 #undef COVMAP_V1
    506 
    507   // Return the structural hash associated with the function.
    508   template <support::endianness Endian> uint64_t getFuncHash() const {
    509     return support::endian::byte_swap<uint64_t, Endian>(FuncHash);
    510   }
    511   // Return the coverage map data size for the funciton.
    512   template <support::endianness Endian> uint32_t getDataSize() const {
    513     return support::endian::byte_swap<uint32_t, Endian>(DataSize);
    514   }
    515   // Return function lookup key. The value is consider opaque.
    516   template <support::endianness Endian> IntPtrT getFuncNameRef() const {
    517     return support::endian::byte_swap<IntPtrT, Endian>(NamePtr);
    518   }
    519   // Return the PGO name of the function */
    520   template <support::endianness Endian>
    521   Error getFuncName(InstrProfSymtab &ProfileNames, StringRef &FuncName) const {
    522     IntPtrT NameRef = getFuncNameRef<Endian>();
    523     uint32_t NameS = support::endian::byte_swap<uint32_t, Endian>(NameSize);
    524     FuncName = ProfileNames.getFuncName(NameRef, NameS);
    525     if (NameS && FuncName.empty())
    526       return make_error<CoverageMapError>(coveragemap_error::malformed);
    527     return Error::success();
    528   }
    529 };
    530 
    531 struct CovMapFunctionRecord {
    532 #define COVMAP_FUNC_RECORD(Type, LLVMType, Name, Init) Type Name;
    533 #include "llvm/ProfileData/InstrProfData.inc"
    534 
    535   // Return the structural hash associated with the function.
    536   template <support::endianness Endian> uint64_t getFuncHash() const {
    537     return support::endian::byte_swap<uint64_t, Endian>(FuncHash);
    538   }
    539   // Return the coverage map data size for the funciton.
    540   template <support::endianness Endian> uint32_t getDataSize() const {
    541     return support::endian::byte_swap<uint32_t, Endian>(DataSize);
    542   }
    543   // Return function lookup key. The value is consider opaque.
    544   template <support::endianness Endian> uint64_t getFuncNameRef() const {
    545     return support::endian::byte_swap<uint64_t, Endian>(NameRef);
    546   }
    547   // Return the PGO name of the function */
    548   template <support::endianness Endian>
    549   Error getFuncName(InstrProfSymtab &ProfileNames, StringRef &FuncName) const {
    550     uint64_t NameRef = getFuncNameRef<Endian>();
    551     FuncName = ProfileNames.getFuncName(NameRef);
    552     return Error::success();
    553   }
    554 };
    555 
    556 // Per module coverage mapping data header, i.e. CoverageMapFileHeader
    557 // documented above.
    558 struct CovMapHeader {
    559 #define COVMAP_HEADER(Type, LLVMType, Name, Init) Type Name;
    560 #include "llvm/ProfileData/InstrProfData.inc"
    561   template <support::endianness Endian> uint32_t getNRecords() const {
    562     return support::endian::byte_swap<uint32_t, Endian>(NRecords);
    563   }
    564   template <support::endianness Endian> uint32_t getFilenamesSize() const {
    565     return support::endian::byte_swap<uint32_t, Endian>(FilenamesSize);
    566   }
    567   template <support::endianness Endian> uint32_t getCoverageSize() const {
    568     return support::endian::byte_swap<uint32_t, Endian>(CoverageSize);
    569   }
    570   template <support::endianness Endian> uint32_t getVersion() const {
    571     return support::endian::byte_swap<uint32_t, Endian>(Version);
    572   }
    573 };
    574 
    575 LLVM_PACKED_END
    576 
    577 enum CovMapVersion {
    578   Version1 = 0,
    579   // Function's name reference from CovMapFuncRecord is changed from raw
    580   // name string pointer to MD5 to support name section compression. Name
    581   // section is also compressed.
    582   Version2 = 1,
    583   // The current version is Version2
    584   CurrentVersion = INSTR_PROF_COVMAP_VERSION
    585 };
    586 
    587 template <int CovMapVersion, class IntPtrT> struct CovMapTraits {
    588   typedef CovMapFunctionRecord CovMapFuncRecordType;
    589   typedef uint64_t NameRefType;
    590 };
    591 
    592 template <class IntPtrT> struct CovMapTraits<CovMapVersion::Version1, IntPtrT> {
    593   typedef CovMapFunctionRecordV1<IntPtrT> CovMapFuncRecordType;
    594   typedef IntPtrT NameRefType;
    595 };
    596 
    597 } // end namespace coverage
    598 
    599 /// \brief Provide DenseMapInfo for CounterExpression
    600 template<> struct DenseMapInfo<coverage::CounterExpression> {
    601   static inline coverage::CounterExpression getEmptyKey() {
    602     using namespace coverage;
    603     return CounterExpression(CounterExpression::ExprKind::Subtract,
    604                              Counter::getCounter(~0U),
    605                              Counter::getCounter(~0U));
    606   }
    607 
    608   static inline coverage::CounterExpression getTombstoneKey() {
    609     using namespace coverage;
    610     return CounterExpression(CounterExpression::ExprKind::Add,
    611                              Counter::getCounter(~0U),
    612                              Counter::getCounter(~0U));
    613   }
    614 
    615   static unsigned getHashValue(const coverage::CounterExpression &V) {
    616     return static_cast<unsigned>(
    617         hash_combine(V.Kind, V.LHS.getKind(), V.LHS.getCounterID(),
    618                      V.RHS.getKind(), V.RHS.getCounterID()));
    619   }
    620 
    621   static bool isEqual(const coverage::CounterExpression &LHS,
    622                       const coverage::CounterExpression &RHS) {
    623     return LHS.Kind == RHS.Kind && LHS.LHS == RHS.LHS && LHS.RHS == RHS.RHS;
    624   }
    625 };
    626 
    627 } // end namespace llvm
    628 
    629 #endif // LLVM_PROFILEDATA_COVERAGEMAPPING_H_
    630