1 //=-- InstrProfWriter.cpp - Instrumented profiling writer -------------------=// 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 support for writing profiling data for clang's 11 // instrumentation based PGO and coverage. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "llvm/ProfileData/InstrProfWriter.h" 16 #include "llvm/ADT/StringExtras.h" 17 #include "llvm/Support/EndianStream.h" 18 #include "llvm/Support/OnDiskHashTable.h" 19 #include <tuple> 20 21 using namespace llvm; 22 23 namespace { 24 static support::endianness ValueProfDataEndianness = support::little; 25 26 class InstrProfRecordTrait { 27 public: 28 typedef StringRef key_type; 29 typedef StringRef key_type_ref; 30 31 typedef const InstrProfWriter::ProfilingData *const data_type; 32 typedef const InstrProfWriter::ProfilingData *const data_type_ref; 33 34 typedef uint64_t hash_value_type; 35 typedef uint64_t offset_type; 36 37 static hash_value_type ComputeHash(key_type_ref K) { 38 return IndexedInstrProf::ComputeHash(K); 39 } 40 41 static std::pair<offset_type, offset_type> 42 EmitKeyDataLength(raw_ostream &Out, key_type_ref K, data_type_ref V) { 43 using namespace llvm::support; 44 endian::Writer<little> LE(Out); 45 46 offset_type N = K.size(); 47 LE.write<offset_type>(N); 48 49 offset_type M = 0; 50 for (const auto &ProfileData : *V) { 51 const InstrProfRecord &ProfRecord = ProfileData.second; 52 M += sizeof(uint64_t); // The function hash 53 M += sizeof(uint64_t); // The size of the Counts vector 54 M += ProfRecord.Counts.size() * sizeof(uint64_t); 55 56 // Value data 57 M += ValueProfData::getSize(ProfileData.second); 58 } 59 LE.write<offset_type>(M); 60 61 return std::make_pair(N, M); 62 } 63 64 static void EmitKey(raw_ostream &Out, key_type_ref K, offset_type N){ 65 Out.write(K.data(), N); 66 } 67 68 static void EmitData(raw_ostream &Out, key_type_ref, data_type_ref V, 69 offset_type) { 70 using namespace llvm::support; 71 endian::Writer<little> LE(Out); 72 for (const auto &ProfileData : *V) { 73 const InstrProfRecord &ProfRecord = ProfileData.second; 74 75 LE.write<uint64_t>(ProfileData.first); // Function hash 76 LE.write<uint64_t>(ProfRecord.Counts.size()); 77 for (uint64_t I : ProfRecord.Counts) 78 LE.write<uint64_t>(I); 79 80 // Write value data 81 std::unique_ptr<ValueProfData> VDataPtr = 82 ValueProfData::serializeFrom(ProfileData.second); 83 uint32_t S = VDataPtr->getSize(); 84 VDataPtr->swapBytesFromHost(ValueProfDataEndianness); 85 Out.write((const char *)VDataPtr.get(), S); 86 } 87 } 88 }; 89 } 90 91 // Internal interface for testing purpose only. 92 void InstrProfWriter::setValueProfDataEndianness( 93 support::endianness Endianness) { 94 ValueProfDataEndianness = Endianness; 95 } 96 97 std::error_code InstrProfWriter::addRecord(InstrProfRecord &&I, 98 uint64_t Weight) { 99 auto &ProfileDataMap = FunctionData[I.Name]; 100 101 bool NewFunc; 102 ProfilingData::iterator Where; 103 std::tie(Where, NewFunc) = 104 ProfileDataMap.insert(std::make_pair(I.Hash, InstrProfRecord())); 105 InstrProfRecord &Dest = Where->second; 106 107 instrprof_error Result; 108 if (NewFunc) { 109 // We've never seen a function with this name and hash, add it. 110 Dest = std::move(I); 111 // Fix up the name to avoid dangling reference. 112 Dest.Name = FunctionData.find(Dest.Name)->getKey(); 113 Result = instrprof_error::success; 114 if (Weight > 1) { 115 for (auto &Count : Dest.Counts) { 116 bool Overflowed; 117 Count = SaturatingMultiply(Count, Weight, &Overflowed); 118 if (Overflowed && Result == instrprof_error::success) { 119 Result = instrprof_error::counter_overflow; 120 } 121 } 122 } 123 } else { 124 // We're updating a function we've seen before. 125 Result = Dest.merge(I, Weight); 126 } 127 128 // We keep track of the max function count as we go for simplicity. 129 // Update this statistic no matter the result of the merge. 130 if (Dest.Counts[0] > MaxFunctionCount) 131 MaxFunctionCount = Dest.Counts[0]; 132 133 return Result; 134 } 135 136 std::pair<uint64_t, uint64_t> InstrProfWriter::writeImpl(raw_ostream &OS) { 137 OnDiskChainedHashTableGenerator<InstrProfRecordTrait> Generator; 138 139 // Populate the hash table generator. 140 for (const auto &I : FunctionData) 141 Generator.insert(I.getKey(), &I.getValue()); 142 143 using namespace llvm::support; 144 endian::Writer<little> LE(OS); 145 146 // Write the header. 147 IndexedInstrProf::Header Header; 148 Header.Magic = IndexedInstrProf::Magic; 149 Header.Version = IndexedInstrProf::Version; 150 Header.MaxFunctionCount = MaxFunctionCount; 151 Header.HashType = static_cast<uint64_t>(IndexedInstrProf::HashType); 152 Header.HashOffset = 0; 153 int N = sizeof(IndexedInstrProf::Header) / sizeof(uint64_t); 154 155 // Only write out all the fields execpt 'HashOffset'. We need 156 // to remember the offset of that field to allow back patching 157 // later. 158 for (int I = 0; I < N - 1; I++) 159 LE.write<uint64_t>(reinterpret_cast<uint64_t *>(&Header)[I]); 160 161 // Save a space to write the hash table start location. 162 uint64_t HashTableStartLoc = OS.tell(); 163 // Reserve the space for HashOffset field. 164 LE.write<uint64_t>(0); 165 // Write the hash table. 166 uint64_t HashTableStart = Generator.Emit(OS); 167 168 return std::make_pair(HashTableStartLoc, HashTableStart); 169 } 170 171 void InstrProfWriter::write(raw_fd_ostream &OS) { 172 // Write the hash table. 173 auto TableStart = writeImpl(OS); 174 175 // Go back and fill in the hash table start. 176 using namespace support; 177 OS.seek(TableStart.first); 178 // Now patch the HashOffset field previously reserved. 179 endian::Writer<little>(OS).write<uint64_t>(TableStart.second); 180 } 181 182 static const char *ValueProfKindStr[] = { 183 #define VALUE_PROF_KIND(Enumerator, Value) #Enumerator, 184 #include "llvm/ProfileData/InstrProfData.inc" 185 }; 186 187 void InstrProfWriter::writeRecordInText(const InstrProfRecord &Func, 188 InstrProfSymtab &Symtab, 189 raw_fd_ostream &OS) { 190 OS << Func.Name << "\n"; 191 OS << "# Func Hash:\n" << Func.Hash << "\n"; 192 OS << "# Num Counters:\n" << Func.Counts.size() << "\n"; 193 OS << "# Counter Values:\n"; 194 for (uint64_t Count : Func.Counts) 195 OS << Count << "\n"; 196 197 uint32_t NumValueKinds = Func.getNumValueKinds(); 198 if (!NumValueKinds) { 199 OS << "\n"; 200 return; 201 } 202 203 OS << "# Num Value Kinds:\n" << Func.getNumValueKinds() << "\n"; 204 for (uint32_t VK = 0; VK < IPVK_Last + 1; VK++) { 205 uint32_t NS = Func.getNumValueSites(VK); 206 if (!NS) 207 continue; 208 OS << "# ValueKind = " << ValueProfKindStr[VK] << ":\n" << VK << "\n"; 209 OS << "# NumValueSites:\n" << NS << "\n"; 210 for (uint32_t S = 0; S < NS; S++) { 211 uint32_t ND = Func.getNumValueDataForSite(VK, S); 212 OS << ND << "\n"; 213 std::unique_ptr<InstrProfValueData[]> VD = Func.getValueForSite(VK, S); 214 for (uint32_t I = 0; I < ND; I++) { 215 if (VK == IPVK_IndirectCallTarget) 216 OS << Symtab.getFuncName(VD[I].Value) << ":" << VD[I].Count << "\n"; 217 else 218 OS << VD[I].Value << ":" << VD[I].Count << "\n"; 219 } 220 } 221 } 222 223 OS << "\n"; 224 } 225 226 void InstrProfWriter::writeText(raw_fd_ostream &OS) { 227 InstrProfSymtab Symtab; 228 for (const auto &I : FunctionData) 229 Symtab.addFuncName(I.getKey()); 230 Symtab.finalizeSymtab(); 231 232 for (const auto &I : FunctionData) 233 for (const auto &Func : I.getValue()) 234 writeRecordInText(Func.second, Symtab, OS); 235 } 236 237 std::unique_ptr<MemoryBuffer> InstrProfWriter::writeBuffer() { 238 std::string Data; 239 llvm::raw_string_ostream OS(Data); 240 // Write the hash table. 241 auto TableStart = writeImpl(OS); 242 OS.flush(); 243 244 // Go back and fill in the hash table start. 245 using namespace support; 246 uint64_t Bytes = endian::byte_swap<uint64_t, little>(TableStart.second); 247 Data.replace(TableStart.first, sizeof(uint64_t), (const char *)&Bytes, 248 sizeof(uint64_t)); 249 250 // Return this in an aligned memory buffer. 251 return MemoryBuffer::getMemBufferCopy(Data); 252 } 253
