1//=-- InstrProf.cpp - Instrumented 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 support for clang's instrumentation based PGO and 11// coverage. 12// 13//===----------------------------------------------------------------------===// 14 15#include "llvm/ProfileData/InstrProf.h" 16#include "llvm/ADT/StringExtras.h" 17#include "llvm/IR/Constants.h" 18#include "llvm/IR/Function.h" 19#include "llvm/IR/GlobalVariable.h" 20#include "llvm/IR/Module.h" 21#include "llvm/Support/Compression.h" 22#include "llvm/Support/ErrorHandling.h" 23#include "llvm/Support/LEB128.h" 24#include "llvm/Support/ManagedStatic.h" 25 26using namespace llvm; 27 28namespace { 29class InstrProfErrorCategoryType : public std::error_category { 30 const char *name() const LLVM_NOEXCEPT override { return "llvm.instrprof"; } 31 std::string message(int IE) const override { 32 instrprof_error E = static_cast<instrprof_error>(IE); 33 switch (E) { 34 case instrprof_error::success: 35 return "Success"; 36 case instrprof_error::eof: 37 return "End of File"; 38 case instrprof_error::unrecognized_format: 39 return "Unrecognized instrumentation profile encoding format"; 40 case instrprof_error::bad_magic: 41 return "Invalid instrumentation profile data (bad magic)"; 42 case instrprof_error::bad_header: 43 return "Invalid instrumentation profile data (file header is corrupt)"; 44 case instrprof_error::unsupported_version: 45 return "Unsupported instrumentation profile format version"; 46 case instrprof_error::unsupported_hash_type: 47 return "Unsupported instrumentation profile hash type"; 48 case instrprof_error::too_large: 49 return "Too much profile data"; 50 case instrprof_error::truncated: 51 return "Truncated profile data"; 52 case instrprof_error::malformed: 53 return "Malformed instrumentation profile data"; 54 case instrprof_error::unknown_function: 55 return "No profile data available for function"; 56 case instrprof_error::hash_mismatch: 57 return "Function control flow change detected (hash mismatch)"; 58 case instrprof_error::count_mismatch: 59 return "Function basic block count change detected (counter mismatch)"; 60 case instrprof_error::counter_overflow: 61 return "Counter overflow"; 62 case instrprof_error::value_site_count_mismatch: 63 return "Function value site count change detected (counter mismatch)"; 64 } 65 llvm_unreachable("A value of instrprof_error has no message."); 66 } 67}; 68} 69 70static ManagedStatic<InstrProfErrorCategoryType> ErrorCategory; 71 72const std::error_category &llvm::instrprof_category() { 73 return *ErrorCategory; 74} 75 76namespace llvm { 77 78std::string getPGOFuncName(StringRef RawFuncName, 79 GlobalValue::LinkageTypes Linkage, 80 StringRef FileName, 81 uint64_t Version LLVM_ATTRIBUTE_UNUSED) { 82 83 // Function names may be prefixed with a binary '1' to indicate 84 // that the backend should not modify the symbols due to any platform 85 // naming convention. Do not include that '1' in the PGO profile name. 86 if (RawFuncName[0] == '\1') 87 RawFuncName = RawFuncName.substr(1); 88 89 std::string FuncName = RawFuncName; 90 if (llvm::GlobalValue::isLocalLinkage(Linkage)) { 91 // For local symbols, prepend the main file name to distinguish them. 92 // Do not include the full path in the file name since there's no guarantee 93 // that it will stay the same, e.g., if the files are checked out from 94 // version control in different locations. 95 if (FileName.empty()) 96 FuncName = FuncName.insert(0, "<unknown>:"); 97 else 98 FuncName = FuncName.insert(0, FileName.str() + ":"); 99 } 100 return FuncName; 101} 102 103std::string getPGOFuncName(const Function &F, uint64_t Version) { 104 return getPGOFuncName(F.getName(), F.getLinkage(), F.getParent()->getName(), 105 Version); 106} 107 108StringRef getFuncNameWithoutPrefix(StringRef PGOFuncName, StringRef FileName) { 109 if (FileName.empty()) 110 return PGOFuncName; 111 // Drop the file name including ':'. See also getPGOFuncName. 112 if (PGOFuncName.startswith(FileName)) 113 PGOFuncName = PGOFuncName.drop_front(FileName.size() + 1); 114 return PGOFuncName; 115} 116 117// \p FuncName is the string used as profile lookup key for the function. A 118// symbol is created to hold the name. Return the legalized symbol name. 119static std::string getPGOFuncNameVarName(StringRef FuncName, 120 GlobalValue::LinkageTypes Linkage) { 121 std::string VarName = getInstrProfNameVarPrefix(); 122 VarName += FuncName; 123 124 if (!GlobalValue::isLocalLinkage(Linkage)) 125 return VarName; 126 127 // Now fix up illegal chars in local VarName that may upset the assembler. 128 const char *InvalidChars = "-:<>\"'"; 129 size_t found = VarName.find_first_of(InvalidChars); 130 while (found != std::string::npos) { 131 VarName[found] = '_'; 132 found = VarName.find_first_of(InvalidChars, found + 1); 133 } 134 return VarName; 135} 136 137GlobalVariable *createPGOFuncNameVar(Module &M, 138 GlobalValue::LinkageTypes Linkage, 139 StringRef FuncName) { 140 141 // We generally want to match the function's linkage, but available_externally 142 // and extern_weak both have the wrong semantics, and anything that doesn't 143 // need to link across compilation units doesn't need to be visible at all. 144 if (Linkage == GlobalValue::ExternalWeakLinkage) 145 Linkage = GlobalValue::LinkOnceAnyLinkage; 146 else if (Linkage == GlobalValue::AvailableExternallyLinkage) 147 Linkage = GlobalValue::LinkOnceODRLinkage; 148 else if (Linkage == GlobalValue::InternalLinkage || 149 Linkage == GlobalValue::ExternalLinkage) 150 Linkage = GlobalValue::PrivateLinkage; 151 152 auto *Value = ConstantDataArray::getString(M.getContext(), FuncName, false); 153 auto FuncNameVar = 154 new GlobalVariable(M, Value->getType(), true, Linkage, Value, 155 getPGOFuncNameVarName(FuncName, Linkage)); 156 157 // Hide the symbol so that we correctly get a copy for each executable. 158 if (!GlobalValue::isLocalLinkage(FuncNameVar->getLinkage())) 159 FuncNameVar->setVisibility(GlobalValue::HiddenVisibility); 160 161 return FuncNameVar; 162} 163 164GlobalVariable *createPGOFuncNameVar(Function &F, StringRef FuncName) { 165 return createPGOFuncNameVar(*F.getParent(), F.getLinkage(), FuncName); 166} 167 168int collectPGOFuncNameStrings(const std::vector<std::string> &NameStrs, 169 bool doCompression, std::string &Result) { 170 uint8_t Header[16], *P = Header; 171 std::string UncompressedNameStrings = 172 join(NameStrs.begin(), NameStrs.end(), StringRef(" ")); 173 174 unsigned EncLen = encodeULEB128(UncompressedNameStrings.length(), P); 175 P += EncLen; 176 177 auto WriteStringToResult = [&](size_t CompressedLen, 178 const std::string &InputStr) { 179 EncLen = encodeULEB128(CompressedLen, P); 180 P += EncLen; 181 char *HeaderStr = reinterpret_cast<char *>(&Header[0]); 182 unsigned HeaderLen = P - &Header[0]; 183 Result.append(HeaderStr, HeaderLen); 184 Result += InputStr; 185 return 0; 186 }; 187 188 if (!doCompression) 189 return WriteStringToResult(0, UncompressedNameStrings); 190 191 SmallVector<char, 128> CompressedNameStrings; 192 zlib::Status Success = 193 zlib::compress(StringRef(UncompressedNameStrings), CompressedNameStrings, 194 zlib::BestSizeCompression); 195 196 if (Success != zlib::StatusOK) 197 return 1; 198 199 return WriteStringToResult( 200 CompressedNameStrings.size(), 201 std::string(CompressedNameStrings.data(), CompressedNameStrings.size())); 202} 203 204StringRef getPGOFuncNameInitializer(GlobalVariable *NameVar) { 205 auto *Arr = cast<ConstantDataArray>(NameVar->getInitializer()); 206 StringRef NameStr = 207 Arr->isCString() ? Arr->getAsCString() : Arr->getAsString(); 208 return NameStr; 209} 210 211int collectPGOFuncNameStrings(const std::vector<GlobalVariable *> &NameVars, 212 std::string &Result) { 213 std::vector<std::string> NameStrs; 214 for (auto *NameVar : NameVars) { 215 NameStrs.push_back(getPGOFuncNameInitializer(NameVar)); 216 } 217 return collectPGOFuncNameStrings(NameStrs, zlib::isAvailable(), Result); 218} 219 220int readPGOFuncNameStrings(StringRef NameStrings, InstrProfSymtab &Symtab) { 221 const uint8_t *P = reinterpret_cast<const uint8_t *>(NameStrings.data()); 222 const uint8_t *EndP = reinterpret_cast<const uint8_t *>(NameStrings.data() + 223 NameStrings.size()); 224 while (P < EndP) { 225 uint32_t N; 226 uint64_t UncompressedSize = decodeULEB128(P, &N); 227 P += N; 228 uint64_t CompressedSize = decodeULEB128(P, &N); 229 P += N; 230 bool isCompressed = (CompressedSize != 0); 231 SmallString<128> UncompressedNameStrings; 232 StringRef NameStrings; 233 if (isCompressed) { 234 StringRef CompressedNameStrings(reinterpret_cast<const char *>(P), 235 CompressedSize); 236 if (zlib::uncompress(CompressedNameStrings, UncompressedNameStrings, 237 UncompressedSize) != zlib::StatusOK) 238 return 1; 239 P += CompressedSize; 240 NameStrings = StringRef(UncompressedNameStrings.data(), 241 UncompressedNameStrings.size()); 242 } else { 243 NameStrings = 244 StringRef(reinterpret_cast<const char *>(P), UncompressedSize); 245 P += UncompressedSize; 246 } 247 // Now parse the name strings. 248 SmallVector<StringRef, 0> Names; 249 NameStrings.split(Names, ' '); 250 for (StringRef &Name : Names) 251 Symtab.addFuncName(Name); 252 253 while (P < EndP && *P == 0) 254 P++; 255 } 256 Symtab.finalizeSymtab(); 257 return 0; 258} 259 260instrprof_error InstrProfValueSiteRecord::merge(InstrProfValueSiteRecord &Input, 261 uint64_t Weight) { 262 this->sortByTargetValues(); 263 Input.sortByTargetValues(); 264 auto I = ValueData.begin(); 265 auto IE = ValueData.end(); 266 instrprof_error Result = instrprof_error::success; 267 for (auto J = Input.ValueData.begin(), JE = Input.ValueData.end(); J != JE; 268 ++J) { 269 while (I != IE && I->Value < J->Value) 270 ++I; 271 if (I != IE && I->Value == J->Value) { 272 bool Overflowed; 273 I->Count = SaturatingMultiplyAdd(J->Count, Weight, I->Count, &Overflowed); 274 if (Overflowed) 275 Result = instrprof_error::counter_overflow; 276 ++I; 277 continue; 278 } 279 ValueData.insert(I, *J); 280 } 281 return Result; 282} 283 284instrprof_error InstrProfValueSiteRecord::scale(uint64_t Weight) { 285 instrprof_error Result = instrprof_error::success; 286 for (auto I = ValueData.begin(), IE = ValueData.end(); I != IE; ++I) { 287 bool Overflowed; 288 I->Count = SaturatingMultiply(I->Count, Weight, &Overflowed); 289 if (Overflowed) 290 Result = instrprof_error::counter_overflow; 291 } 292 return Result; 293} 294 295// Merge Value Profile data from Src record to this record for ValueKind. 296// Scale merged value counts by \p Weight. 297instrprof_error InstrProfRecord::mergeValueProfData(uint32_t ValueKind, 298 InstrProfRecord &Src, 299 uint64_t Weight) { 300 uint32_t ThisNumValueSites = getNumValueSites(ValueKind); 301 uint32_t OtherNumValueSites = Src.getNumValueSites(ValueKind); 302 if (ThisNumValueSites != OtherNumValueSites) 303 return instrprof_error::value_site_count_mismatch; 304 std::vector<InstrProfValueSiteRecord> &ThisSiteRecords = 305 getValueSitesForKind(ValueKind); 306 std::vector<InstrProfValueSiteRecord> &OtherSiteRecords = 307 Src.getValueSitesForKind(ValueKind); 308 instrprof_error Result = instrprof_error::success; 309 for (uint32_t I = 0; I < ThisNumValueSites; I++) 310 MergeResult(Result, ThisSiteRecords[I].merge(OtherSiteRecords[I], Weight)); 311 return Result; 312} 313 314instrprof_error InstrProfRecord::merge(InstrProfRecord &Other, 315 uint64_t Weight) { 316 // If the number of counters doesn't match we either have bad data 317 // or a hash collision. 318 if (Counts.size() != Other.Counts.size()) 319 return instrprof_error::count_mismatch; 320 321 instrprof_error Result = instrprof_error::success; 322 323 for (size_t I = 0, E = Other.Counts.size(); I < E; ++I) { 324 bool Overflowed; 325 Counts[I] = 326 SaturatingMultiplyAdd(Other.Counts[I], Weight, Counts[I], &Overflowed); 327 if (Overflowed) 328 Result = instrprof_error::counter_overflow; 329 } 330 331 for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind) 332 MergeResult(Result, mergeValueProfData(Kind, Other, Weight)); 333 334 return Result; 335} 336 337instrprof_error InstrProfRecord::scaleValueProfData(uint32_t ValueKind, 338 uint64_t Weight) { 339 uint32_t ThisNumValueSites = getNumValueSites(ValueKind); 340 std::vector<InstrProfValueSiteRecord> &ThisSiteRecords = 341 getValueSitesForKind(ValueKind); 342 instrprof_error Result = instrprof_error::success; 343 for (uint32_t I = 0; I < ThisNumValueSites; I++) 344 MergeResult(Result, ThisSiteRecords[I].scale(Weight)); 345 return Result; 346} 347 348instrprof_error InstrProfRecord::scale(uint64_t Weight) { 349 instrprof_error Result = instrprof_error::success; 350 for (auto &Count : this->Counts) { 351 bool Overflowed; 352 Count = SaturatingMultiply(Count, Weight, &Overflowed); 353 if (Overflowed && Result == instrprof_error::success) { 354 Result = instrprof_error::counter_overflow; 355 } 356 } 357 for (uint32_t Kind = IPVK_First; Kind <= IPVK_Last; ++Kind) 358 MergeResult(Result, scaleValueProfData(Kind, Weight)); 359 360 return Result; 361} 362 363// Map indirect call target name hash to name string. 364uint64_t InstrProfRecord::remapValue(uint64_t Value, uint32_t ValueKind, 365 ValueMapType *ValueMap) { 366 if (!ValueMap) 367 return Value; 368 switch (ValueKind) { 369 case IPVK_IndirectCallTarget: { 370 auto Result = 371 std::lower_bound(ValueMap->begin(), ValueMap->end(), Value, 372 [](const std::pair<uint64_t, uint64_t> &LHS, 373 uint64_t RHS) { return LHS.first < RHS; }); 374 if (Result != ValueMap->end()) 375 Value = (uint64_t)Result->second; 376 break; 377 } 378 } 379 return Value; 380} 381 382void InstrProfRecord::addValueData(uint32_t ValueKind, uint32_t Site, 383 InstrProfValueData *VData, uint32_t N, 384 ValueMapType *ValueMap) { 385 for (uint32_t I = 0; I < N; I++) { 386 VData[I].Value = remapValue(VData[I].Value, ValueKind, ValueMap); 387 } 388 std::vector<InstrProfValueSiteRecord> &ValueSites = 389 getValueSitesForKind(ValueKind); 390 if (N == 0) 391 ValueSites.push_back(InstrProfValueSiteRecord()); 392 else 393 ValueSites.emplace_back(VData, VData + N); 394} 395 396#define INSTR_PROF_COMMON_API_IMPL 397#include "llvm/ProfileData/InstrProfData.inc" 398 399/*! 400 * \brief ValueProfRecordClosure Interface implementation for InstrProfRecord 401 * class. These C wrappers are used as adaptors so that C++ code can be 402 * invoked as callbacks. 403 */ 404uint32_t getNumValueKindsInstrProf(const void *Record) { 405 return reinterpret_cast<const InstrProfRecord *>(Record)->getNumValueKinds(); 406} 407 408uint32_t getNumValueSitesInstrProf(const void *Record, uint32_t VKind) { 409 return reinterpret_cast<const InstrProfRecord *>(Record) 410 ->getNumValueSites(VKind); 411} 412 413uint32_t getNumValueDataInstrProf(const void *Record, uint32_t VKind) { 414 return reinterpret_cast<const InstrProfRecord *>(Record) 415 ->getNumValueData(VKind); 416} 417 418uint32_t getNumValueDataForSiteInstrProf(const void *R, uint32_t VK, 419 uint32_t S) { 420 return reinterpret_cast<const InstrProfRecord *>(R) 421 ->getNumValueDataForSite(VK, S); 422} 423 424void getValueForSiteInstrProf(const void *R, InstrProfValueData *Dst, 425 uint32_t K, uint32_t S, 426 uint64_t (*Mapper)(uint32_t, uint64_t)) { 427 return reinterpret_cast<const InstrProfRecord *>(R)->getValueForSite( 428 Dst, K, S, Mapper); 429} 430 431ValueProfData *allocValueProfDataInstrProf(size_t TotalSizeInBytes) { 432 ValueProfData *VD = 433 (ValueProfData *)(new (::operator new(TotalSizeInBytes)) ValueProfData()); 434 memset(VD, 0, TotalSizeInBytes); 435 return VD; 436} 437 438static ValueProfRecordClosure InstrProfRecordClosure = { 439 0, 440 getNumValueKindsInstrProf, 441 getNumValueSitesInstrProf, 442 getNumValueDataInstrProf, 443 getNumValueDataForSiteInstrProf, 444 0, 445 getValueForSiteInstrProf, 446 allocValueProfDataInstrProf}; 447 448// Wrapper implementation using the closure mechanism. 449uint32_t ValueProfData::getSize(const InstrProfRecord &Record) { 450 InstrProfRecordClosure.Record = &Record; 451 return getValueProfDataSize(&InstrProfRecordClosure); 452} 453 454// Wrapper implementation using the closure mechanism. 455std::unique_ptr<ValueProfData> 456ValueProfData::serializeFrom(const InstrProfRecord &Record) { 457 InstrProfRecordClosure.Record = &Record; 458 459 std::unique_ptr<ValueProfData> VPD( 460 serializeValueProfDataFrom(&InstrProfRecordClosure, nullptr)); 461 return VPD; 462} 463 464void ValueProfRecord::deserializeTo(InstrProfRecord &Record, 465 InstrProfRecord::ValueMapType *VMap) { 466 Record.reserveSites(Kind, NumValueSites); 467 468 InstrProfValueData *ValueData = getValueProfRecordValueData(this); 469 for (uint64_t VSite = 0; VSite < NumValueSites; ++VSite) { 470 uint8_t ValueDataCount = this->SiteCountArray[VSite]; 471 Record.addValueData(Kind, VSite, ValueData, ValueDataCount, VMap); 472 ValueData += ValueDataCount; 473 } 474} 475 476// For writing/serializing, Old is the host endianness, and New is 477// byte order intended on disk. For Reading/deserialization, Old 478// is the on-disk source endianness, and New is the host endianness. 479void ValueProfRecord::swapBytes(support::endianness Old, 480 support::endianness New) { 481 using namespace support; 482 if (Old == New) 483 return; 484 485 if (getHostEndianness() != Old) { 486 sys::swapByteOrder<uint32_t>(NumValueSites); 487 sys::swapByteOrder<uint32_t>(Kind); 488 } 489 uint32_t ND = getValueProfRecordNumValueData(this); 490 InstrProfValueData *VD = getValueProfRecordValueData(this); 491 492 // No need to swap byte array: SiteCountArrray. 493 for (uint32_t I = 0; I < ND; I++) { 494 sys::swapByteOrder<uint64_t>(VD[I].Value); 495 sys::swapByteOrder<uint64_t>(VD[I].Count); 496 } 497 if (getHostEndianness() == Old) { 498 sys::swapByteOrder<uint32_t>(NumValueSites); 499 sys::swapByteOrder<uint32_t>(Kind); 500 } 501} 502 503void ValueProfData::deserializeTo(InstrProfRecord &Record, 504 InstrProfRecord::ValueMapType *VMap) { 505 if (NumValueKinds == 0) 506 return; 507 508 ValueProfRecord *VR = getFirstValueProfRecord(this); 509 for (uint32_t K = 0; K < NumValueKinds; K++) { 510 VR->deserializeTo(Record, VMap); 511 VR = getValueProfRecordNext(VR); 512 } 513} 514 515template <class T> 516static T swapToHostOrder(const unsigned char *&D, support::endianness Orig) { 517 using namespace support; 518 if (Orig == little) 519 return endian::readNext<T, little, unaligned>(D); 520 else 521 return endian::readNext<T, big, unaligned>(D); 522} 523 524static std::unique_ptr<ValueProfData> allocValueProfData(uint32_t TotalSize) { 525 return std::unique_ptr<ValueProfData>(new (::operator new(TotalSize)) 526 ValueProfData()); 527} 528 529instrprof_error ValueProfData::checkIntegrity() { 530 if (NumValueKinds > IPVK_Last + 1) 531 return instrprof_error::malformed; 532 // Total size needs to be mulltiple of quadword size. 533 if (TotalSize % sizeof(uint64_t)) 534 return instrprof_error::malformed; 535 536 ValueProfRecord *VR = getFirstValueProfRecord(this); 537 for (uint32_t K = 0; K < this->NumValueKinds; K++) { 538 if (VR->Kind > IPVK_Last) 539 return instrprof_error::malformed; 540 VR = getValueProfRecordNext(VR); 541 if ((char *)VR - (char *)this > (ptrdiff_t)TotalSize) 542 return instrprof_error::malformed; 543 } 544 return instrprof_error::success; 545} 546 547ErrorOr<std::unique_ptr<ValueProfData>> 548ValueProfData::getValueProfData(const unsigned char *D, 549 const unsigned char *const BufferEnd, 550 support::endianness Endianness) { 551 using namespace support; 552 if (D + sizeof(ValueProfData) > BufferEnd) 553 return instrprof_error::truncated; 554 555 const unsigned char *Header = D; 556 uint32_t TotalSize = swapToHostOrder<uint32_t>(Header, Endianness); 557 if (D + TotalSize > BufferEnd) 558 return instrprof_error::too_large; 559 560 std::unique_ptr<ValueProfData> VPD = allocValueProfData(TotalSize); 561 memcpy(VPD.get(), D, TotalSize); 562 // Byte swap. 563 VPD->swapBytesToHost(Endianness); 564 565 instrprof_error EC = VPD->checkIntegrity(); 566 if (EC != instrprof_error::success) 567 return EC; 568 569 return std::move(VPD); 570} 571 572void ValueProfData::swapBytesToHost(support::endianness Endianness) { 573 using namespace support; 574 if (Endianness == getHostEndianness()) 575 return; 576 577 sys::swapByteOrder<uint32_t>(TotalSize); 578 sys::swapByteOrder<uint32_t>(NumValueKinds); 579 580 ValueProfRecord *VR = getFirstValueProfRecord(this); 581 for (uint32_t K = 0; K < NumValueKinds; K++) { 582 VR->swapBytes(Endianness, getHostEndianness()); 583 VR = getValueProfRecordNext(VR); 584 } 585} 586 587void ValueProfData::swapBytesFromHost(support::endianness Endianness) { 588 using namespace support; 589 if (Endianness == getHostEndianness()) 590 return; 591 592 ValueProfRecord *VR = getFirstValueProfRecord(this); 593 for (uint32_t K = 0; K < NumValueKinds; K++) { 594 ValueProfRecord *NVR = getValueProfRecordNext(VR); 595 VR->swapBytes(getHostEndianness(), Endianness); 596 VR = NVR; 597 } 598 sys::swapByteOrder<uint32_t>(TotalSize); 599 sys::swapByteOrder<uint32_t>(NumValueKinds); 600} 601 602} 603