src/llvm/include/llvm/ProfileData/SampleProf.h

   1 //=-- SampleProf.h - Sampling profiling format support --------------------===//
   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 // This file contains common definitions used in the reading and writing of
  11 // sample profile data.
  12 //
  13 //===----------------------------------------------------------------------===//
  14 #ifndef LLVM_PROFILEDATA_SAMPLEPROF_H_
  15 #define LLVM_PROFILEDATA_SAMPLEPROF_H_
  16
  17 #include "llvm/ADT/DenseMap.h"
  18 #include "llvm/ADT/SmallVector.h"
  19 #include "llvm/ADT/StringMap.h"
  20 #include "llvm/Support/Debug.h"
  21 #include "llvm/Support/raw_ostream.h"
  22 #include <system_error>
  23
  24 namespace llvm {
  25
  26 const std::error_category &sampleprof_category();
  27
  28 enum class sampleprof_error {
  29   success = 0,
  30   bad_magic,
  31   unsupported_version,
  32   too_large,
  33   truncated,
  34   malformed,
  35   unrecognized_format
  36 };
  37
  38 inline std::error_code make_error_code(sampleprof_error E) {
  39   return std::error_code(static_cast<int>(E), sampleprof_category());
  40 }
  41
  42 } // end namespace llvm
  43
  44 namespace std {
  45 template <>
  46 struct is_error_code_enum<llvm::sampleprof_error> : std::true_type {};
  47 }
  48
  49 namespace llvm {
  50
  51 namespace sampleprof {
  52
  53 static inline uint64_t SPMagic() {
  54   return uint64_t('S') << (64 - 8) | uint64_t('P') << (64 - 16) |
  55          uint64_t('R') << (64 - 24) | uint64_t('O') << (64 - 32) |
  56          uint64_t('F') << (64 - 40) | uint64_t('4') << (64 - 48) |
  57          uint64_t('2') << (64 - 56) | uint64_t(0xff);
  58 }
  59
  60 static inline uint64_t SPVersion() { return 100; }
  61
  62 /// \brief Represents the relative location of an instruction.
  63 ///
  64 /// Instruction locations are specified by the line offset from the
  65 /// beginning of the function (marked by the line where the function
  66 /// header is) and the discriminator value within that line.
  67 ///
  68 /// The discriminator value is useful to distinguish instructions
  69 /// that are on the same line but belong to different basic blocks
  70 /// (e.g., the two post-increment instructions in "if (p) x++; else y++;").
  71 struct LineLocation {
  72   LineLocation(int L, unsigned D) : LineOffset(L), Discriminator(D) {}
  73   int LineOffset;
  74   unsigned Discriminator;
  75 };
  76
  77 } // End namespace sampleprof
  78
  79 template <> struct DenseMapInfo<sampleprof::LineLocation> {
  80   typedef DenseMapInfo<int> OffsetInfo;
  81   typedef DenseMapInfo<unsigned> DiscriminatorInfo;
  82   static inline sampleprof::LineLocation getEmptyKey() {
  83     return sampleprof::LineLocation(OffsetInfo::getEmptyKey(),
  84                                     DiscriminatorInfo::getEmptyKey());
  85   }
  86   static inline sampleprof::LineLocation getTombstoneKey() {
  87     return sampleprof::LineLocation(OffsetInfo::getTombstoneKey(),
  88                                     DiscriminatorInfo::getTombstoneKey());
  89   }
  90   static inline unsigned getHashValue(sampleprof::LineLocation Val) {
  91     return DenseMapInfo<std::pair<int, unsigned>>::getHashValue(
  92         std::pair<int, unsigned>(Val.LineOffset, Val.Discriminator));
  93   }
  94   static inline bool isEqual(sampleprof::LineLocation LHS,
  95                              sampleprof::LineLocation RHS) {
  96     return LHS.LineOffset == RHS.LineOffset &&
  97            LHS.Discriminator == RHS.Discriminator;
  98   }
  99 };
 100
 101 namespace sampleprof {
 102
 103 /// \brief Representation of a single sample record.
 104 ///
 105 /// A sample record is represented by a positive integer value, which
 106 /// indicates how frequently was the associated line location executed.
 107 ///
 108 /// Additionally, if the associated location contains a function call,
 109 /// the record will hold a list of all the possible called targets. For
 110 /// direct calls, this will be the exact function being invoked. For
 111 /// indirect calls (function pointers, virtual table dispatch), this
 112 /// will be a list of one or more functions.
 113 class SampleRecord {
 114 public:
 115   typedef StringMap<unsigned> CallTargetMap;
 116
 117   SampleRecord() : NumSamples(0), CallTargets() {}
 118
 119   /// \brief Increment the number of samples for this record by \p S.
 120   ///
 121   /// Sample counts accumulate using saturating arithmetic, to avoid wrapping
 122   /// around unsigned integers.
 123   void addSamples(unsigned S) {
 124     if (NumSamples <= std::numeric_limits<unsigned>::max() - S)
 125       NumSamples += S;
 126     else
 127       NumSamples = std::numeric_limits<unsigned>::max();
 128   }
 129
 130   /// \brief Add called function \p F with samples \p S.
 131   ///
 132   /// Sample counts accumulate using saturating arithmetic, to avoid wrapping
 133   /// around unsigned integers.
 134   void addCalledTarget(StringRef F, unsigned S) {
 135     unsigned &TargetSamples = CallTargets[F];
 136     if (TargetSamples <= std::numeric_limits<unsigned>::max() - S)
 137       TargetSamples += S;
 138     else
 139       TargetSamples = std::numeric_limits<unsigned>::max();
 140   }
 141
 142   /// \brief Return true if this sample record contains function calls.
 143   bool hasCalls() const { return CallTargets.size() > 0; }
 144
 145   unsigned getSamples() const { return NumSamples; }
 146   const CallTargetMap &getCallTargets() const { return CallTargets; }
 147
 148   /// \brief Merge the samples in \p Other into this record.
 149   void merge(const SampleRecord &Other) {
 150     addSamples(Other.getSamples());
 151     for (const auto &I : Other.getCallTargets())
 152       addCalledTarget(I.first(), I.second);
 153   }
 154
 155 private:
 156   unsigned NumSamples;
 157   CallTargetMap CallTargets;
 158 };
 159
 160 typedef DenseMap<LineLocation, SampleRecord> BodySampleMap;
 161
 162 /// \brief Representation of the samples collected for a function.
 163 ///
 164 /// This data structure contains all the collected samples for the body
 165 /// of a function. Each sample corresponds to a LineLocation instance
 166 /// within the body of the function.
 167 class FunctionSamples {
 168 public:
 169   FunctionSamples() : TotalSamples(0), TotalHeadSamples(0) {}
 170   void print(raw_ostream &OS = dbgs());
 171   void addTotalSamples(unsigned Num) { TotalSamples += Num; }
 172   void addHeadSamples(unsigned Num) { TotalHeadSamples += Num; }
 173   void addBodySamples(int LineOffset, unsigned Discriminator, unsigned Num) {
 174     assert(LineOffset >= 0);
 175     // When dealing with instruction weights, we use the value
 176     // zero to indicate the absence of a sample. If we read an
 177     // actual zero from the profile file, use the value 1 to
 178     // avoid the confusion later on.
 179     if (Num == 0)
 180       Num = 1;
 181     BodySamples[LineLocation(LineOffset, Discriminator)].addSamples(Num);
 182   }
 183   void addCalledTargetSamples(int LineOffset, unsigned Discriminator,
 184                               std::string FName, unsigned Num) {
 185     assert(LineOffset >= 0);
 186     BodySamples[LineLocation(LineOffset, Discriminator)].addCalledTarget(FName,
 187                                                                          Num);
 188   }
 189
 190   /// \brief Return the sample record at the given location.
 191   /// Each location is specified by \p LineOffset and \p Discriminator.
 192   SampleRecord &sampleRecordAt(const LineLocation &Loc) {
 193     return BodySamples[Loc];
 194   }
 195
 196   /// \brief Return the number of samples collected at the given location.
 197   /// Each location is specified by \p LineOffset and \p Discriminator.
 198   unsigned samplesAt(int LineOffset, unsigned Discriminator) {
 199     return sampleRecordAt(LineLocation(LineOffset, Discriminator)).getSamples();
 200   }
 201
 202   bool empty() const { return BodySamples.empty(); }
 203
 204   /// \brief Return the total number of samples collected inside the function.
 205   unsigned getTotalSamples() const { return TotalSamples; }
 206
 207   /// \brief Return the total number of samples collected at the head of the
 208   /// function.
 209   unsigned getHeadSamples() const { return TotalHeadSamples; }
 210
 211   /// \brief Return all the samples collected in the body of the function.
 212   const BodySampleMap &getBodySamples() const { return BodySamples; }
 213
 214   /// \brief Merge the samples in \p Other into this one.
 215   void merge(const FunctionSamples &Other) {
 216     addTotalSamples(Other.getTotalSamples());
 217     addHeadSamples(Other.getHeadSamples());
 218     for (const auto &I : Other.getBodySamples()) {
 219       const LineLocation &Loc = I.first;
 220       const SampleRecord &Rec = I.second;
 221       sampleRecordAt(Loc).merge(Rec);
 222     }
 223   }
 224
 225 private:
 226   /// \brief Total number of samples collected inside this function.
 227   ///
 228   /// Samples are cumulative, they include all the samples collected
 229   /// inside this function and all its inlined callees.
 230   unsigned TotalSamples;
 231
 232   /// \brief Total number of samples collected at the head of the function.
 233   unsigned TotalHeadSamples;
 234
 235   /// \brief Map instruction locations to collected samples.
 236   ///
 237   /// Each entry in this map contains the number of samples
 238   /// collected at the corresponding line offset. All line locations
 239   /// are an offset from the start of the function.
 240   BodySampleMap BodySamples;
 241 };
 242
 243 } // End namespace sampleprof
 244
 245 } // End namespace llvm
 246
 247 #endif // LLVM_PROFILEDATA_SAMPLEPROF_H_