llvm/lib/ProfileData/InstrProfWriter.cpp

   1 //===- InstrProfWriter.cpp - Instrumented profiling writer ----------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file contains support for writing profiling data for clang's
  10 // instrumentation based PGO and coverage.
  11 //
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "llvm/ProfileData/InstrProfWriter.h"
  15 #include "llvm/ADT/STLExtras.h"
  16 #include "llvm/ADT/StringRef.h"
  17 #include "llvm/IR/ProfileSummary.h"
  18 #include "llvm/ProfileData/InstrProf.h"
  19 #include "llvm/ProfileData/ProfileCommon.h"
  20 #include "llvm/Support/Endian.h"
  21 #include "llvm/Support/EndianStream.h"
  22 #include "llvm/Support/Error.h"
  23 #include "llvm/Support/MemoryBuffer.h"
  24 #include "llvm/Support/OnDiskHashTable.h"
  25 #include "llvm/Support/raw_ostream.h"
  26 #include <algorithm>
  27 #include <cstdint>
  28 #include <memory>
  29 #include <string>
  30 #include <tuple>
  31 #include <utility>
  32 #include <vector>
  33
  34 using namespace llvm;
  35
  36 // A struct to define how the data stream should be patched. For Indexed
  37 // profiling, only uint64_t data type is needed.
  38 struct PatchItem {
  39   uint64_t Pos; // Where to patch.
  40   uint64_t *D;  // Pointer to an array of source data.
  41   int N;        // Number of elements in \c D array.
  42 };
  43
  44 namespace llvm {
  45
  46 // A wrapper class to abstract writer stream with support of bytes
  47 // back patching.
  48 class ProfOStream {
  49 public:
  50   ProfOStream(raw_fd_ostream &FD)
  51       : IsFDOStream(true), OS(FD), LE(FD, support::little) {}
  52   ProfOStream(raw_string_ostream &STR)
  53       : IsFDOStream(false), OS(STR), LE(STR, support::little) {}
  54
  55   uint64_t tell() { return OS.tell(); }
  56   void write(uint64_t V) { LE.write<uint64_t>(V); }
  57
  58   // \c patch can only be called when all data is written and flushed.
  59   // For raw_string_ostream, the patch is done on the target string
  60   // directly and it won't be reflected in the stream's internal buffer.
  61   void patch(PatchItem *P, int NItems) {
  62     using namespace support;
  63
  64     if (IsFDOStream) {
  65       raw_fd_ostream &FDOStream = static_cast<raw_fd_ostream &>(OS);
  66       for (int K = 0; K < NItems; K++) {
  67         FDOStream.seek(P[K].Pos);
  68         for (int I = 0; I < P[K].N; I++)
  69           write(P[K].D[I]);
  70       }
  71     } else {
  72       raw_string_ostream &SOStream = static_cast<raw_string_ostream &>(OS);
  73       std::string &Data = SOStream.str(); // with flush
  74       for (int K = 0; K < NItems; K++) {
  75         for (int I = 0; I < P[K].N; I++) {
  76           uint64_t Bytes = endian::byte_swap<uint64_t, little>(P[K].D[I]);
  77           Data.replace(P[K].Pos + I * sizeof(uint64_t), sizeof(uint64_t),
  78                        (const char *)&Bytes, sizeof(uint64_t));
  79         }
  80       }
  81     }
  82   }
  83
  84   // If \c OS is an instance of \c raw_fd_ostream, this field will be
  85   // true. Otherwise, \c OS will be an raw_string_ostream.
  86   bool IsFDOStream;
  87   raw_ostream &OS;
  88   support::endian::Writer LE;
  89 };
  90
  91 class InstrProfRecordWriterTrait {
  92 public:
  93   using key_type = StringRef;
  94   using key_type_ref = StringRef;
  95
  96   using data_type = const InstrProfWriter::ProfilingData *const;
  97   using data_type_ref = const InstrProfWriter::ProfilingData *const;
  98
  99   using hash_value_type = uint64_t;
 100   using offset_type = uint64_t;
 101
 102   support::endianness ValueProfDataEndianness = support::little;
 103   InstrProfSummaryBuilder *SummaryBuilder;
 104   InstrProfSummaryBuilder *CSSummaryBuilder;
 105
 106   InstrProfRecordWriterTrait() = default;
 107
 108   static hash_value_type ComputeHash(key_type_ref K) {
 109     return IndexedInstrProf::ComputeHash(K);
 110   }
 111
 112   static std::pair<offset_type, offset_type>
 113   EmitKeyDataLength(raw_ostream &Out, key_type_ref K, data_type_ref V) {
 114     using namespace support;
 115
 116     endian::Writer LE(Out, little);
 117
 118     offset_type N = K.size();
 119     LE.write<offset_type>(N);
 120
 121     offset_type M = 0;
 122     for (const auto &ProfileData : *V) {
 123       const InstrProfRecord &ProfRecord = ProfileData.second;
 124       M += sizeof(uint64_t); // The function hash
 125       M += sizeof(uint64_t); // The size of the Counts vector
 126       M += ProfRecord.Counts.size() * sizeof(uint64_t);
 127
 128       // Value data
 129       M += ValueProfData::getSize(ProfileData.second);
 130     }
 131     LE.write<offset_type>(M);
 132
 133     return std::make_pair(N, M);
 134   }
 135
 136   void EmitKey(raw_ostream &Out, key_type_ref K, offset_type N) {
 137     Out.write(K.data(), N);
 138   }
 139
 140   void EmitData(raw_ostream &Out, key_type_ref, data_type_ref V, offset_type) {
 141     using namespace support;
 142
 143     endian::Writer LE(Out, little);
 144     for (const auto &ProfileData : *V) {
 145       const InstrProfRecord &ProfRecord = ProfileData.second;
 146       if (NamedInstrProfRecord::hasCSFlagInHash(ProfileData.first))
 147         CSSummaryBuilder->addRecord(ProfRecord);
 148       else
 149         SummaryBuilder->addRecord(ProfRecord);
 150
 151       LE.write<uint64_t>(ProfileData.first); // Function hash
 152       LE.write<uint64_t>(ProfRecord.Counts.size());
 153       for (uint64_t I : ProfRecord.Counts)
 154         LE.write<uint64_t>(I);
 155
 156       // Write value data
 157       std::unique_ptr<ValueProfData> VDataPtr =
 158           ValueProfData::serializeFrom(ProfileData.second);
 159       uint32_t S = VDataPtr->getSize();
 160       VDataPtr->swapBytesFromHost(ValueProfDataEndianness);
 161       Out.write((const char *)VDataPtr.get(), S);
 162     }
 163   }
 164 };
 165
 166 } // end namespace llvm
 167
 168 InstrProfWriter::InstrProfWriter(bool Sparse, bool InstrEntryBBEnabled)
 169     : Sparse(Sparse), InstrEntryBBEnabled(InstrEntryBBEnabled),
 170       InfoObj(new InstrProfRecordWriterTrait()) {}
 171
 172 InstrProfWriter::~InstrProfWriter() { delete InfoObj; }
 173
 174 // Internal interface for testing purpose only.
 175 void InstrProfWriter::setValueProfDataEndianness(
 176     support::endianness Endianness) {
 177   InfoObj->ValueProfDataEndianness = Endianness;
 178 }
 179
 180 void InstrProfWriter::setOutputSparse(bool Sparse) {
 181   this->Sparse = Sparse;
 182 }
 183
 184 void InstrProfWriter::addRecord(NamedInstrProfRecord &&I, uint64_t Weight,
 185                                 function_ref<void(Error)> Warn) {
 186   auto Name = I.Name;
 187   auto Hash = I.Hash;
 188   addRecord(Name, Hash, std::move(I), Weight, Warn);
 189 }
 190
 191 void InstrProfWriter::overlapRecord(NamedInstrProfRecord &&Other,
 192                                     OverlapStats &Overlap,
 193                                     OverlapStats &FuncLevelOverlap,
 194                                     const OverlapFuncFilters &FuncFilter) {
 195   auto Name = Other.Name;
 196   auto Hash = Other.Hash;
 197   Other.accumulateCounts(FuncLevelOverlap.Test);
 198   if (FunctionData.find(Name) == FunctionData.end()) {
 199     Overlap.addOneUnique(FuncLevelOverlap.Test);
 200     return;
 201   }
 202   if (FuncLevelOverlap.Test.CountSum < 1.0f) {
 203     Overlap.Overlap.NumEntries += 1;
 204     return;
 205   }
 206   auto &ProfileDataMap = FunctionData[Name];
 207   bool NewFunc;
 208   ProfilingData::iterator Where;
 209   std::tie(Where, NewFunc) =
 210       ProfileDataMap.insert(std::make_pair(Hash, InstrProfRecord()));
 211   if (NewFunc) {
 212     Overlap.addOneMismatch(FuncLevelOverlap.Test);
 213     return;
 214   }
 215   InstrProfRecord &Dest = Where->second;
 216
 217   uint64_t ValueCutoff = FuncFilter.ValueCutoff;
 218   if (!FuncFilter.NameFilter.empty() &&
 219       Name.find(FuncFilter.NameFilter) != Name.npos)
 220     ValueCutoff = 0;
 221
 222   Dest.overlap(Other, Overlap, FuncLevelOverlap, ValueCutoff);
 223 }
 224
 225 void InstrProfWriter::addRecord(StringRef Name, uint64_t Hash,
 226                                 InstrProfRecord &&I, uint64_t Weight,
 227                                 function_ref<void(Error)> Warn) {
 228   auto &ProfileDataMap = FunctionData[Name];
 229
 230   bool NewFunc;
 231   ProfilingData::iterator Where;
 232   std::tie(Where, NewFunc) =
 233       ProfileDataMap.insert(std::make_pair(Hash, InstrProfRecord()));
 234   InstrProfRecord &Dest = Where->second;
 235
 236   auto MapWarn = [&](instrprof_error E) {
 237     Warn(make_error<InstrProfError>(E));
 238   };
 239
 240   if (NewFunc) {
 241     // We've never seen a function with this name and hash, add it.
 242     Dest = std::move(I);
 243     if (Weight > 1)
 244       Dest.scale(Weight, 1, MapWarn);
 245   } else {
 246     // We're updating a function we've seen before.
 247     Dest.merge(I, Weight, MapWarn);
 248   }
 249
 250   Dest.sortValueData();
 251 }
 252
 253 void InstrProfWriter::mergeRecordsFromWriter(InstrProfWriter &&IPW,
 254                                              function_ref<void(Error)> Warn) {
 255   for (auto &I : IPW.FunctionData)
 256     for (auto &Func : I.getValue())
 257       addRecord(I.getKey(), Func.first, std::move(Func.second), 1, Warn);
 258 }
 259
 260 bool InstrProfWriter::shouldEncodeData(const ProfilingData &PD) {
 261   if (!Sparse)
 262     return true;
 263   for (const auto &Func : PD) {
 264     const InstrProfRecord &IPR = Func.second;
 265     if (llvm::any_of(IPR.Counts, [](uint64_t Count) { return Count > 0; }))
 266       return true;
 267   }
 268   return false;
 269 }
 270
 271 static void setSummary(IndexedInstrProf::Summary *TheSummary,
 272                        ProfileSummary &PS) {
 273   using namespace IndexedInstrProf;
 274
 275   std::vector<ProfileSummaryEntry> &Res = PS.getDetailedSummary();
 276   TheSummary->NumSummaryFields = Summary::NumKinds;
 277   TheSummary->NumCutoffEntries = Res.size();
 278   TheSummary->set(Summary::MaxFunctionCount, PS.getMaxFunctionCount());
 279   TheSummary->set(Summary::MaxBlockCount, PS.getMaxCount());
 280   TheSummary->set(Summary::MaxInternalBlockCount, PS.getMaxInternalCount());
 281   TheSummary->set(Summary::TotalBlockCount, PS.getTotalCount());
 282   TheSummary->set(Summary::TotalNumBlocks, PS.getNumCounts());
 283   TheSummary->set(Summary::TotalNumFunctions, PS.getNumFunctions());
 284   for (unsigned I = 0; I < Res.size(); I++)
 285     TheSummary->setEntry(I, Res[I]);
 286 }
 287
 288 Error InstrProfWriter::writeImpl(ProfOStream &OS) {
 289   using namespace IndexedInstrProf;
 290
 291   OnDiskChainedHashTableGenerator<InstrProfRecordWriterTrait> Generator;
 292
 293   InstrProfSummaryBuilder ISB(ProfileSummaryBuilder::DefaultCutoffs);
 294   InfoObj->SummaryBuilder = &ISB;
 295   InstrProfSummaryBuilder CSISB(ProfileSummaryBuilder::DefaultCutoffs);
 296   InfoObj->CSSummaryBuilder = &CSISB;
 297
 298   // Populate the hash table generator.
 299   for (const auto &I : FunctionData)
 300     if (shouldEncodeData(I.getValue()))
 301       Generator.insert(I.getKey(), &I.getValue());
 302   // Write the header.
 303   IndexedInstrProf::Header Header;
 304   Header.Magic = IndexedInstrProf::Magic;
 305   Header.Version = IndexedInstrProf::ProfVersion::CurrentVersion;
 306   if (ProfileKind == PF_IRLevel)
 307     Header.Version |= VARIANT_MASK_IR_PROF;
 308   if (ProfileKind == PF_IRLevelWithCS) {
 309     Header.Version |= VARIANT_MASK_IR_PROF;
 310     Header.Version |= VARIANT_MASK_CSIR_PROF;
 311   }
 312   if (InstrEntryBBEnabled)
 313     Header.Version |= VARIANT_MASK_INSTR_ENTRY;
 314
 315   Header.Unused = 0;
 316   Header.HashType = static_cast<uint64_t>(IndexedInstrProf::HashType);
 317   Header.HashOffset = 0;
 318   int N = sizeof(IndexedInstrProf::Header) / sizeof(uint64_t);
 319
 320   // Only write out all the fields except 'HashOffset'. We need
 321   // to remember the offset of that field to allow back patching
 322   // later.
 323   for (int I = 0; I < N - 1; I++)
 324     OS.write(reinterpret_cast<uint64_t *>(&Header)[I]);
 325
 326   // Save the location of Header.HashOffset field in \c OS.
 327   uint64_t HashTableStartFieldOffset = OS.tell();
 328   // Reserve the space for HashOffset field.
 329   OS.write(0);
 330
 331   // Reserve space to write profile summary data.
 332   uint32_t NumEntries = ProfileSummaryBuilder::DefaultCutoffs.size();
 333   uint32_t SummarySize = Summary::getSize(Summary::NumKinds, NumEntries);
 334   // Remember the summary offset.
 335   uint64_t SummaryOffset = OS.tell();
 336   for (unsigned I = 0; I < SummarySize / sizeof(uint64_t); I++)
 337     OS.write(0);
 338   uint64_t CSSummaryOffset = 0;
 339   uint64_t CSSummarySize = 0;
 340   if (ProfileKind == PF_IRLevelWithCS) {
 341     CSSummaryOffset = OS.tell();
 342     CSSummarySize = SummarySize / sizeof(uint64_t);
 343     for (unsigned I = 0; I < CSSummarySize; I++)
 344       OS.write(0);
 345   }
 346
 347   // Write the hash table.
 348   uint64_t HashTableStart = Generator.Emit(OS.OS, *InfoObj);
 349
 350   // Allocate space for data to be serialized out.
 351   std::unique_ptr<IndexedInstrProf::Summary> TheSummary =
 352       IndexedInstrProf::allocSummary(SummarySize);
 353   // Compute the Summary and copy the data to the data
 354   // structure to be serialized out (to disk or buffer).
 355   std::unique_ptr<ProfileSummary> PS = ISB.getSummary();
 356   setSummary(TheSummary.get(), *PS);
 357   InfoObj->SummaryBuilder = nullptr;
 358
 359   // For Context Sensitive summary.
 360   std::unique_ptr<IndexedInstrProf::Summary> TheCSSummary = nullptr;
 361   if (ProfileKind == PF_IRLevelWithCS) {
 362     TheCSSummary = IndexedInstrProf::allocSummary(SummarySize);
 363     std::unique_ptr<ProfileSummary> CSPS = CSISB.getSummary();
 364     setSummary(TheCSSummary.get(), *CSPS);
 365   }
 366   InfoObj->CSSummaryBuilder = nullptr;
 367
 368   // Now do the final patch:
 369   PatchItem PatchItems[] = {
 370       // Patch the Header.HashOffset field.
 371       {HashTableStartFieldOffset, &HashTableStart, 1},
 372       // Patch the summary data.
 373       {SummaryOffset, reinterpret_cast<uint64_t *>(TheSummary.get()),
 374        (int)(SummarySize / sizeof(uint64_t))},
 375       {CSSummaryOffset, reinterpret_cast<uint64_t *>(TheCSSummary.get()),
 376        (int)CSSummarySize}};
 377
 378   OS.patch(PatchItems, sizeof(PatchItems) / sizeof(*PatchItems));
 379
 380   for (const auto &I : FunctionData)
 381     for (const auto &F : I.getValue())
 382       if (Error E = validateRecord(F.second))
 383         return E;
 384
 385   return Error::success();
 386 }
 387
 388 Error InstrProfWriter::write(raw_fd_ostream &OS) {
 389   // Write the hash table.
 390   ProfOStream POS(OS);
 391   return writeImpl(POS);
 392 }
 393
 394 std::unique_ptr<MemoryBuffer> InstrProfWriter::writeBuffer() {
 395   std::string Data;
 396   raw_string_ostream OS(Data);
 397   ProfOStream POS(OS);
 398   // Write the hash table.
 399   if (Error E = writeImpl(POS))
 400     return nullptr;
 401   // Return this in an aligned memory buffer.
 402   return MemoryBuffer::getMemBufferCopy(Data);
 403 }
 404
 405 static const char *ValueProfKindStr[] = {
 406 #define VALUE_PROF_KIND(Enumerator, Value, Descr) #Enumerator,
 407 #include "llvm/ProfileData/InstrProfData.inc"
 408 };
 409
 410 Error InstrProfWriter::validateRecord(const InstrProfRecord &Func) {
 411   for (uint32_t VK = 0; VK <= IPVK_Last; VK++) {
 412     uint32_t NS = Func.getNumValueSites(VK);
 413     if (!NS)
 414       continue;
 415     for (uint32_t S = 0; S < NS; S++) {
 416       uint32_t ND = Func.getNumValueDataForSite(VK, S);
 417       std::unique_ptr<InstrProfValueData[]> VD = Func.getValueForSite(VK, S);
 418       bool WasZero = false;
 419       for (uint32_t I = 0; I < ND; I++)
 420         if ((VK != IPVK_IndirectCallTarget) && (VD[I].Value == 0)) {
 421           if (WasZero)
 422             return make_error<InstrProfError>(instrprof_error::invalid_prof);
 423           WasZero = true;
 424         }
 425     }
 426   }
 427
 428   return Error::success();
 429 }
 430
 431 void InstrProfWriter::writeRecordInText(StringRef Name, uint64_t Hash,
 432                                         const InstrProfRecord &Func,
 433                                         InstrProfSymtab &Symtab,
 434                                         raw_fd_ostream &OS) {
 435   OS << Name << "\n";
 436   OS << "# Func Hash:\n" << Hash << "\n";
 437   OS << "# Num Counters:\n" << Func.Counts.size() << "\n";
 438   OS << "# Counter Values:\n";
 439   for (uint64_t Count : Func.Counts)
 440     OS << Count << "\n";
 441
 442   uint32_t NumValueKinds = Func.getNumValueKinds();
 443   if (!NumValueKinds) {
 444     OS << "\n";
 445     return;
 446   }
 447
 448   OS << "# Num Value Kinds:\n" << Func.getNumValueKinds() << "\n";
 449   for (uint32_t VK = 0; VK < IPVK_Last + 1; VK++) {
 450     uint32_t NS = Func.getNumValueSites(VK);
 451     if (!NS)
 452       continue;
 453     OS << "# ValueKind = " << ValueProfKindStr[VK] << ":\n" << VK << "\n";
 454     OS << "# NumValueSites:\n" << NS << "\n";
 455     for (uint32_t S = 0; S < NS; S++) {
 456       uint32_t ND = Func.getNumValueDataForSite(VK, S);
 457       OS << ND << "\n";
 458       std::unique_ptr<InstrProfValueData[]> VD = Func.getValueForSite(VK, S);
 459       for (uint32_t I = 0; I < ND; I++) {
 460         if (VK == IPVK_IndirectCallTarget)
 461           OS << Symtab.getFuncNameOrExternalSymbol(VD[I].Value) << ":"
 462              << VD[I].Count << "\n";
 463         else
 464           OS << VD[I].Value << ":" << VD[I].Count << "\n";
 465       }
 466     }
 467   }
 468
 469   OS << "\n";
 470 }
 471
 472 Error InstrProfWriter::writeText(raw_fd_ostream &OS) {
 473   if (ProfileKind == PF_IRLevel)
 474     OS << "# IR level Instrumentation Flag\n:ir\n";
 475   else if (ProfileKind == PF_IRLevelWithCS)
 476     OS << "# CSIR level Instrumentation Flag\n:csir\n";
 477   if (InstrEntryBBEnabled)
 478     OS << "# Always instrument the function entry block\n:entry_first\n";
 479   InstrProfSymtab Symtab;
 480
 481   using FuncPair = detail::DenseMapPair<uint64_t, InstrProfRecord>;
 482   using RecordType = std::pair<StringRef, FuncPair>;
 483   SmallVector<RecordType, 4> OrderedFuncData;
 484
 485   for (const auto &I : FunctionData) {
 486     if (shouldEncodeData(I.getValue())) {
 487       if (Error E = Symtab.addFuncName(I.getKey()))
 488         return E;
 489       for (const auto &Func : I.getValue())
 490         OrderedFuncData.push_back(std::make_pair(I.getKey(), Func));
 491     }
 492   }
 493
 494   llvm::sort(OrderedFuncData, [](const RecordType &A, const RecordType &B) {
 495     return std::tie(A.first, A.second.first) <
 496            std::tie(B.first, B.second.first);
 497   });
 498
 499   for (const auto &record : OrderedFuncData) {
 500     const StringRef &Name = record.first;
 501     const FuncPair &Func = record.second;
 502     writeRecordInText(Name, Func.first, Func.second, Symtab, OS);
 503   }
 504
 505   for (const auto &record : OrderedFuncData) {
 506     const FuncPair &Func = record.second;
 507     if (Error E = validateRecord(Func.second))
 508       return E;
 509   }
 510
 511   return Error::success();
 512 }