1 //===- bolt/Core/BinaryContext.cpp - Low-level context --------------------===// 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 implements the BinaryContext class. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "bolt/Core/BinaryContext.h" 14 #include "bolt/Core/BinaryEmitter.h" 15 #include "bolt/Core/BinaryFunction.h" 16 #include "bolt/Utils/CommandLineOpts.h" 17 #include "bolt/Utils/Utils.h" 18 #include "llvm/ADT/STLExtras.h" 19 #include "llvm/ADT/Twine.h" 20 #include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h" 21 #include "llvm/DebugInfo/DWARF/DWARFFormValue.h" 22 #include "llvm/DebugInfo/DWARF/DWARFUnit.h" 23 #include "llvm/MC/MCAsmLayout.h" 24 #include "llvm/MC/MCAssembler.h" 25 #include "llvm/MC/MCContext.h" 26 #include "llvm/MC/MCDisassembler/MCDisassembler.h" 27 #include "llvm/MC/MCInstPrinter.h" 28 #include "llvm/MC/MCObjectStreamer.h" 29 #include "llvm/MC/MCObjectWriter.h" 30 #include "llvm/MC/MCRegisterInfo.h" 31 #include "llvm/MC/MCSectionELF.h" 32 #include "llvm/MC/MCStreamer.h" 33 #include "llvm/MC/MCSubtargetInfo.h" 34 #include "llvm/MC/MCSymbol.h" 35 #include "llvm/Support/CommandLine.h" 36 #include "llvm/Support/Error.h" 37 #include "llvm/Support/Regex.h" 38 #include <algorithm> 39 #include <functional> 40 #include <iterator> 41 #include <unordered_set> 42 43 using namespace llvm; 44 45 #undef DEBUG_TYPE 46 #define DEBUG_TYPE "bolt" 47 48 namespace opts { 49 50 cl::opt<bool> NoHugePages("no-huge-pages", 51 cl::desc("use regular size pages for code alignment"), 52 cl::Hidden, cl::cat(BoltCategory)); 53 54 static cl::opt<bool> 55 PrintDebugInfo("print-debug-info", 56 cl::desc("print debug info when printing functions"), 57 cl::Hidden, 58 cl::ZeroOrMore, 59 cl::cat(BoltCategory)); 60 61 cl::opt<bool> PrintRelocations( 62 "print-relocations", 63 cl::desc("print relocations when printing functions/objects"), cl::Hidden, 64 cl::cat(BoltCategory)); 65 66 static cl::opt<bool> 67 PrintMemData("print-mem-data", 68 cl::desc("print memory data annotations when printing functions"), 69 cl::Hidden, 70 cl::ZeroOrMore, 71 cl::cat(BoltCategory)); 72 73 cl::opt<std::string> CompDirOverride( 74 "comp-dir-override", 75 cl::desc("overrides DW_AT_comp_dir, and provides an alterantive base " 76 "location, which is used with DW_AT_dwo_name to construct a path " 77 "to *.dwo files."), 78 cl::Hidden, cl::init(""), cl::cat(BoltCategory)); 79 } // namespace opts 80 81 namespace llvm { 82 namespace bolt { 83 84 char BOLTError::ID = 0; 85 86 BOLTError::BOLTError(bool IsFatal, const Twine &S) 87 : IsFatal(IsFatal), Msg(S.str()) {} 88 89 void BOLTError::log(raw_ostream &OS) const { 90 if (IsFatal) 91 OS << "FATAL "; 92 StringRef ErrMsg = StringRef(Msg); 93 // Prepend our error prefix if it is missing 94 if (ErrMsg.empty()) { 95 OS << "BOLT-ERROR\n"; 96 } else { 97 if (!ErrMsg.starts_with("BOLT-ERROR")) 98 OS << "BOLT-ERROR: "; 99 OS << ErrMsg << "\n"; 100 } 101 } 102 103 std::error_code BOLTError::convertToErrorCode() const { 104 return inconvertibleErrorCode(); 105 } 106 107 Error createNonFatalBOLTError(const Twine &S) { 108 return make_error<BOLTError>(/*IsFatal*/ false, S); 109 } 110 111 Error createFatalBOLTError(const Twine &S) { 112 return make_error<BOLTError>(/*IsFatal*/ true, S); 113 } 114 115 void BinaryContext::logBOLTErrorsAndQuitOnFatal(Error E) { 116 handleAllErrors(Error(std::move(E)), [&](const BOLTError &E) { 117 if (!E.getMessage().empty()) 118 E.log(this->errs()); 119 if (E.isFatal()) 120 exit(1); 121 }); 122 } 123 124 BinaryContext::BinaryContext(std::unique_ptr<MCContext> Ctx, 125 std::unique_ptr<DWARFContext> DwCtx, 126 std::unique_ptr<Triple> TheTriple, 127 const Target *TheTarget, std::string TripleName, 128 std::unique_ptr<MCCodeEmitter> MCE, 129 std::unique_ptr<MCObjectFileInfo> MOFI, 130 std::unique_ptr<const MCAsmInfo> AsmInfo, 131 std::unique_ptr<const MCInstrInfo> MII, 132 std::unique_ptr<const MCSubtargetInfo> STI, 133 std::unique_ptr<MCInstPrinter> InstPrinter, 134 std::unique_ptr<const MCInstrAnalysis> MIA, 135 std::unique_ptr<MCPlusBuilder> MIB, 136 std::unique_ptr<const MCRegisterInfo> MRI, 137 std::unique_ptr<MCDisassembler> DisAsm, 138 JournalingStreams Logger) 139 : Ctx(std::move(Ctx)), DwCtx(std::move(DwCtx)), 140 TheTriple(std::move(TheTriple)), TheTarget(TheTarget), 141 TripleName(TripleName), MCE(std::move(MCE)), MOFI(std::move(MOFI)), 142 AsmInfo(std::move(AsmInfo)), MII(std::move(MII)), STI(std::move(STI)), 143 InstPrinter(std::move(InstPrinter)), MIA(std::move(MIA)), 144 MIB(std::move(MIB)), MRI(std::move(MRI)), DisAsm(std::move(DisAsm)), 145 Logger(Logger) { 146 Relocation::Arch = this->TheTriple->getArch(); 147 RegularPageSize = isAArch64() ? RegularPageSizeAArch64 : RegularPageSizeX86; 148 PageAlign = opts::NoHugePages ? RegularPageSize : HugePageSize; 149 } 150 151 BinaryContext::~BinaryContext() { 152 for (BinarySection *Section : Sections) 153 delete Section; 154 for (BinaryFunction *InjectedFunction : InjectedBinaryFunctions) 155 delete InjectedFunction; 156 for (std::pair<const uint64_t, JumpTable *> JTI : JumpTables) 157 delete JTI.second; 158 clearBinaryData(); 159 } 160 161 /// Create BinaryContext for a given architecture \p ArchName and 162 /// triple \p TripleName. 163 Expected<std::unique_ptr<BinaryContext>> BinaryContext::createBinaryContext( 164 Triple TheTriple, StringRef InputFileName, SubtargetFeatures *Features, 165 bool IsPIC, std::unique_ptr<DWARFContext> DwCtx, JournalingStreams Logger) { 166 StringRef ArchName = ""; 167 std::string FeaturesStr = ""; 168 switch (TheTriple.getArch()) { 169 case llvm::Triple::x86_64: 170 if (Features) 171 return createFatalBOLTError( 172 "x86_64 target does not use SubtargetFeatures"); 173 ArchName = "x86-64"; 174 FeaturesStr = "+nopl"; 175 break; 176 case llvm::Triple::aarch64: 177 if (Features) 178 return createFatalBOLTError( 179 "AArch64 target does not use SubtargetFeatures"); 180 ArchName = "aarch64"; 181 FeaturesStr = "+all"; 182 break; 183 case llvm::Triple::riscv64: { 184 ArchName = "riscv64"; 185 if (!Features) 186 return createFatalBOLTError("RISCV target needs SubtargetFeatures"); 187 // We rely on relaxation for some transformations (e.g., promoting all calls 188 // to PseudoCALL and then making JITLink relax them). Since the relax 189 // feature is not stored in the object file, we manually enable it. 190 Features->AddFeature("relax"); 191 FeaturesStr = Features->getString(); 192 break; 193 } 194 default: 195 return createStringError(std::errc::not_supported, 196 "BOLT-ERROR: Unrecognized machine in ELF file"); 197 } 198 199 const std::string TripleName = TheTriple.str(); 200 201 std::string Error; 202 const Target *TheTarget = 203 TargetRegistry::lookupTarget(std::string(ArchName), TheTriple, Error); 204 if (!TheTarget) 205 return createStringError(make_error_code(std::errc::not_supported), 206 Twine("BOLT-ERROR: ", Error)); 207 208 std::unique_ptr<const MCRegisterInfo> MRI( 209 TheTarget->createMCRegInfo(TripleName)); 210 if (!MRI) 211 return createStringError( 212 make_error_code(std::errc::not_supported), 213 Twine("BOLT-ERROR: no register info for target ", TripleName)); 214 215 // Set up disassembler. 216 std::unique_ptr<MCAsmInfo> AsmInfo( 217 TheTarget->createMCAsmInfo(*MRI, TripleName, MCTargetOptions())); 218 if (!AsmInfo) 219 return createStringError( 220 make_error_code(std::errc::not_supported), 221 Twine("BOLT-ERROR: no assembly info for target ", TripleName)); 222 // BOLT creates "func@PLT" symbols for PLT entries. In function assembly dump 223 // we want to emit such names as using @PLT without double quotes to convey 224 // variant kind to the assembler. BOLT doesn't rely on the linker so we can 225 // override the default AsmInfo behavior to emit names the way we want. 226 AsmInfo->setAllowAtInName(true); 227 228 std::unique_ptr<const MCSubtargetInfo> STI( 229 TheTarget->createMCSubtargetInfo(TripleName, "", FeaturesStr)); 230 if (!STI) 231 return createStringError( 232 make_error_code(std::errc::not_supported), 233 Twine("BOLT-ERROR: no subtarget info for target ", TripleName)); 234 235 std::unique_ptr<const MCInstrInfo> MII(TheTarget->createMCInstrInfo()); 236 if (!MII) 237 return createStringError( 238 make_error_code(std::errc::not_supported), 239 Twine("BOLT-ERROR: no instruction info for target ", TripleName)); 240 241 std::unique_ptr<MCContext> Ctx( 242 new MCContext(TheTriple, AsmInfo.get(), MRI.get(), STI.get())); 243 std::unique_ptr<MCObjectFileInfo> MOFI( 244 TheTarget->createMCObjectFileInfo(*Ctx, IsPIC)); 245 Ctx->setObjectFileInfo(MOFI.get()); 246 // We do not support X86 Large code model. Change this in the future. 247 bool Large = false; 248 if (TheTriple.getArch() == llvm::Triple::aarch64) 249 Large = true; 250 unsigned LSDAEncoding = 251 Large ? dwarf::DW_EH_PE_absptr : dwarf::DW_EH_PE_udata4; 252 if (IsPIC) { 253 LSDAEncoding = dwarf::DW_EH_PE_pcrel | 254 (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4); 255 } 256 257 std::unique_ptr<MCDisassembler> DisAsm( 258 TheTarget->createMCDisassembler(*STI, *Ctx)); 259 260 if (!DisAsm) 261 return createStringError( 262 make_error_code(std::errc::not_supported), 263 Twine("BOLT-ERROR: no disassembler info for target ", TripleName)); 264 265 std::unique_ptr<const MCInstrAnalysis> MIA( 266 TheTarget->createMCInstrAnalysis(MII.get())); 267 if (!MIA) 268 return createStringError( 269 make_error_code(std::errc::not_supported), 270 Twine("BOLT-ERROR: failed to create instruction analysis for target ", 271 TripleName)); 272 273 int AsmPrinterVariant = AsmInfo->getAssemblerDialect(); 274 std::unique_ptr<MCInstPrinter> InstructionPrinter( 275 TheTarget->createMCInstPrinter(TheTriple, AsmPrinterVariant, *AsmInfo, 276 *MII, *MRI)); 277 if (!InstructionPrinter) 278 return createStringError( 279 make_error_code(std::errc::not_supported), 280 Twine("BOLT-ERROR: no instruction printer for target ", TripleName)); 281 InstructionPrinter->setPrintImmHex(true); 282 283 std::unique_ptr<MCCodeEmitter> MCE( 284 TheTarget->createMCCodeEmitter(*MII, *Ctx)); 285 286 auto BC = std::make_unique<BinaryContext>( 287 std::move(Ctx), std::move(DwCtx), std::make_unique<Triple>(TheTriple), 288 TheTarget, std::string(TripleName), std::move(MCE), std::move(MOFI), 289 std::move(AsmInfo), std::move(MII), std::move(STI), 290 std::move(InstructionPrinter), std::move(MIA), nullptr, std::move(MRI), 291 std::move(DisAsm), Logger); 292 293 BC->LSDAEncoding = LSDAEncoding; 294 295 BC->MAB = std::unique_ptr<MCAsmBackend>( 296 BC->TheTarget->createMCAsmBackend(*BC->STI, *BC->MRI, MCTargetOptions())); 297 298 BC->setFilename(InputFileName); 299 300 BC->HasFixedLoadAddress = !IsPIC; 301 302 BC->SymbolicDisAsm = std::unique_ptr<MCDisassembler>( 303 BC->TheTarget->createMCDisassembler(*BC->STI, *BC->Ctx)); 304 305 if (!BC->SymbolicDisAsm) 306 return createStringError( 307 make_error_code(std::errc::not_supported), 308 Twine("BOLT-ERROR: no disassembler info for target ", TripleName)); 309 310 return std::move(BC); 311 } 312 313 bool BinaryContext::forceSymbolRelocations(StringRef SymbolName) const { 314 if (opts::HotText && 315 (SymbolName == "__hot_start" || SymbolName == "__hot_end")) 316 return true; 317 318 if (opts::HotData && 319 (SymbolName == "__hot_data_start" || SymbolName == "__hot_data_end")) 320 return true; 321 322 if (SymbolName == "_end") 323 return true; 324 325 return false; 326 } 327 328 std::unique_ptr<MCObjectWriter> 329 BinaryContext::createObjectWriter(raw_pwrite_stream &OS) { 330 return MAB->createObjectWriter(OS); 331 } 332 333 bool BinaryContext::validateObjectNesting() const { 334 auto Itr = BinaryDataMap.begin(); 335 auto End = BinaryDataMap.end(); 336 bool Valid = true; 337 while (Itr != End) { 338 auto Next = std::next(Itr); 339 while (Next != End && 340 Itr->second->getSection() == Next->second->getSection() && 341 Itr->second->containsRange(Next->second->getAddress(), 342 Next->second->getSize())) { 343 if (Next->second->Parent != Itr->second) { 344 this->errs() << "BOLT-WARNING: object nesting incorrect for:\n" 345 << "BOLT-WARNING: " << *Itr->second << "\n" 346 << "BOLT-WARNING: " << *Next->second << "\n"; 347 Valid = false; 348 } 349 ++Next; 350 } 351 Itr = Next; 352 } 353 return Valid; 354 } 355 356 bool BinaryContext::validateHoles() const { 357 bool Valid = true; 358 for (BinarySection &Section : sections()) { 359 for (const Relocation &Rel : Section.relocations()) { 360 uint64_t RelAddr = Rel.Offset + Section.getAddress(); 361 const BinaryData *BD = getBinaryDataContainingAddress(RelAddr); 362 if (!BD) { 363 this->errs() 364 << "BOLT-WARNING: no BinaryData found for relocation at address" 365 << " 0x" << Twine::utohexstr(RelAddr) << " in " << Section.getName() 366 << "\n"; 367 Valid = false; 368 } else if (!BD->getAtomicRoot()) { 369 this->errs() 370 << "BOLT-WARNING: no atomic BinaryData found for relocation at " 371 << "address 0x" << Twine::utohexstr(RelAddr) << " in " 372 << Section.getName() << "\n"; 373 Valid = false; 374 } 375 } 376 } 377 return Valid; 378 } 379 380 void BinaryContext::updateObjectNesting(BinaryDataMapType::iterator GAI) { 381 const uint64_t Address = GAI->second->getAddress(); 382 const uint64_t Size = GAI->second->getSize(); 383 384 auto fixParents = [&](BinaryDataMapType::iterator Itr, 385 BinaryData *NewParent) { 386 BinaryData *OldParent = Itr->second->Parent; 387 Itr->second->Parent = NewParent; 388 ++Itr; 389 while (Itr != BinaryDataMap.end() && OldParent && 390 Itr->second->Parent == OldParent) { 391 Itr->second->Parent = NewParent; 392 ++Itr; 393 } 394 }; 395 396 // Check if the previous symbol contains the newly added symbol. 397 if (GAI != BinaryDataMap.begin()) { 398 BinaryData *Prev = std::prev(GAI)->second; 399 while (Prev) { 400 if (Prev->getSection() == GAI->second->getSection() && 401 Prev->containsRange(Address, Size)) { 402 fixParents(GAI, Prev); 403 } else { 404 fixParents(GAI, nullptr); 405 } 406 Prev = Prev->Parent; 407 } 408 } 409 410 // Check if the newly added symbol contains any subsequent symbols. 411 if (Size != 0) { 412 BinaryData *BD = GAI->second->Parent ? GAI->second->Parent : GAI->second; 413 auto Itr = std::next(GAI); 414 while ( 415 Itr != BinaryDataMap.end() && 416 BD->containsRange(Itr->second->getAddress(), Itr->second->getSize())) { 417 Itr->second->Parent = BD; 418 ++Itr; 419 } 420 } 421 } 422 423 iterator_range<BinaryContext::binary_data_iterator> 424 BinaryContext::getSubBinaryData(BinaryData *BD) { 425 auto Start = std::next(BinaryDataMap.find(BD->getAddress())); 426 auto End = Start; 427 while (End != BinaryDataMap.end() && BD->isAncestorOf(End->second)) 428 ++End; 429 return make_range(Start, End); 430 } 431 432 std::pair<const MCSymbol *, uint64_t> 433 BinaryContext::handleAddressRef(uint64_t Address, BinaryFunction &BF, 434 bool IsPCRel) { 435 if (isAArch64()) { 436 // Check if this is an access to a constant island and create bookkeeping 437 // to keep track of it and emit it later as part of this function. 438 if (MCSymbol *IslandSym = BF.getOrCreateIslandAccess(Address)) 439 return std::make_pair(IslandSym, 0); 440 441 // Detect custom code written in assembly that refers to arbitrary 442 // constant islands from other functions. Write this reference so we 443 // can pull this constant island and emit it as part of this function 444 // too. 445 auto IslandIter = AddressToConstantIslandMap.lower_bound(Address); 446 447 if (IslandIter != AddressToConstantIslandMap.begin() && 448 (IslandIter == AddressToConstantIslandMap.end() || 449 IslandIter->first > Address)) 450 --IslandIter; 451 452 if (IslandIter != AddressToConstantIslandMap.end()) { 453 // Fall-back to referencing the original constant island in the presence 454 // of dynamic relocs, as we currently do not support cloning them. 455 // Notice: we might fail to link because of this, if the original constant 456 // island we are referring would be emitted too far away. 457 if (IslandIter->second->hasDynamicRelocationAtIsland()) { 458 MCSymbol *IslandSym = 459 IslandIter->second->getOrCreateIslandAccess(Address); 460 if (IslandSym) 461 return std::make_pair(IslandSym, 0); 462 } else if (MCSymbol *IslandSym = 463 IslandIter->second->getOrCreateProxyIslandAccess(Address, 464 BF)) { 465 BF.createIslandDependency(IslandSym, IslandIter->second); 466 return std::make_pair(IslandSym, 0); 467 } 468 } 469 } 470 471 // Note that the address does not necessarily have to reside inside 472 // a section, it could be an absolute address too. 473 ErrorOr<BinarySection &> Section = getSectionForAddress(Address); 474 if (Section && Section->isText()) { 475 if (BF.containsAddress(Address, /*UseMaxSize=*/isAArch64())) { 476 if (Address != BF.getAddress()) { 477 // The address could potentially escape. Mark it as another entry 478 // point into the function. 479 if (opts::Verbosity >= 1) { 480 this->outs() << "BOLT-INFO: potentially escaped address 0x" 481 << Twine::utohexstr(Address) << " in function " << BF 482 << '\n'; 483 } 484 BF.HasInternalLabelReference = true; 485 return std::make_pair( 486 BF.addEntryPointAtOffset(Address - BF.getAddress()), 0); 487 } 488 } else { 489 addInterproceduralReference(&BF, Address); 490 } 491 } 492 493 // With relocations, catch jump table references outside of the basic block 494 // containing the indirect jump. 495 if (HasRelocations) { 496 const MemoryContentsType MemType = analyzeMemoryAt(Address, BF); 497 if (MemType == MemoryContentsType::POSSIBLE_PIC_JUMP_TABLE && IsPCRel) { 498 const MCSymbol *Symbol = 499 getOrCreateJumpTable(BF, Address, JumpTable::JTT_PIC); 500 501 return std::make_pair(Symbol, 0); 502 } 503 } 504 505 if (BinaryData *BD = getBinaryDataContainingAddress(Address)) 506 return std::make_pair(BD->getSymbol(), Address - BD->getAddress()); 507 508 // TODO: use DWARF info to get size/alignment here? 509 MCSymbol *TargetSymbol = getOrCreateGlobalSymbol(Address, "DATAat"); 510 LLVM_DEBUG(dbgs() << "Created symbol " << TargetSymbol->getName() << '\n'); 511 return std::make_pair(TargetSymbol, 0); 512 } 513 514 MemoryContentsType BinaryContext::analyzeMemoryAt(uint64_t Address, 515 BinaryFunction &BF) { 516 if (!isX86()) 517 return MemoryContentsType::UNKNOWN; 518 519 ErrorOr<BinarySection &> Section = getSectionForAddress(Address); 520 if (!Section) { 521 // No section - possibly an absolute address. Since we don't allow 522 // internal function addresses to escape the function scope - we 523 // consider it a tail call. 524 if (opts::Verbosity > 1) { 525 this->errs() << "BOLT-WARNING: no section for address 0x" 526 << Twine::utohexstr(Address) << " referenced from function " 527 << BF << '\n'; 528 } 529 return MemoryContentsType::UNKNOWN; 530 } 531 532 if (Section->isVirtual()) { 533 // The contents are filled at runtime. 534 return MemoryContentsType::UNKNOWN; 535 } 536 537 // No support for jump tables in code yet. 538 if (Section->isText()) 539 return MemoryContentsType::UNKNOWN; 540 541 // Start with checking for PIC jump table. We expect non-PIC jump tables 542 // to have high 32 bits set to 0. 543 if (analyzeJumpTable(Address, JumpTable::JTT_PIC, BF)) 544 return MemoryContentsType::POSSIBLE_PIC_JUMP_TABLE; 545 546 if (analyzeJumpTable(Address, JumpTable::JTT_NORMAL, BF)) 547 return MemoryContentsType::POSSIBLE_JUMP_TABLE; 548 549 return MemoryContentsType::UNKNOWN; 550 } 551 552 bool BinaryContext::analyzeJumpTable(const uint64_t Address, 553 const JumpTable::JumpTableType Type, 554 const BinaryFunction &BF, 555 const uint64_t NextJTAddress, 556 JumpTable::AddressesType *EntriesAsAddress, 557 bool *HasEntryInFragment) const { 558 // Target address of __builtin_unreachable. 559 const uint64_t UnreachableAddress = BF.getAddress() + BF.getSize(); 560 561 // Is one of the targets __builtin_unreachable? 562 bool HasUnreachable = false; 563 564 // Does one of the entries match function start address? 565 bool HasStartAsEntry = false; 566 567 // Number of targets other than __builtin_unreachable. 568 uint64_t NumRealEntries = 0; 569 570 // Size of the jump table without trailing __builtin_unreachable entries. 571 size_t TrimmedSize = 0; 572 573 auto addEntryAddress = [&](uint64_t EntryAddress, bool Unreachable = false) { 574 if (!EntriesAsAddress) 575 return; 576 EntriesAsAddress->emplace_back(EntryAddress); 577 if (!Unreachable) 578 TrimmedSize = EntriesAsAddress->size(); 579 }; 580 581 ErrorOr<const BinarySection &> Section = getSectionForAddress(Address); 582 if (!Section) 583 return false; 584 585 // The upper bound is defined by containing object, section limits, and 586 // the next jump table in memory. 587 uint64_t UpperBound = Section->getEndAddress(); 588 const BinaryData *JumpTableBD = getBinaryDataAtAddress(Address); 589 if (JumpTableBD && JumpTableBD->getSize()) { 590 assert(JumpTableBD->getEndAddress() <= UpperBound && 591 "data object cannot cross a section boundary"); 592 UpperBound = JumpTableBD->getEndAddress(); 593 } 594 if (NextJTAddress) 595 UpperBound = std::min(NextJTAddress, UpperBound); 596 597 LLVM_DEBUG({ 598 using JTT = JumpTable::JumpTableType; 599 dbgs() << formatv("BOLT-DEBUG: analyzeJumpTable @{0:x} in {1}, JTT={2}\n", 600 Address, BF.getPrintName(), 601 Type == JTT::JTT_PIC ? "PIC" : "Normal"); 602 }); 603 const uint64_t EntrySize = getJumpTableEntrySize(Type); 604 for (uint64_t EntryAddress = Address; EntryAddress <= UpperBound - EntrySize; 605 EntryAddress += EntrySize) { 606 LLVM_DEBUG(dbgs() << " * Checking 0x" << Twine::utohexstr(EntryAddress) 607 << " -> "); 608 // Check if there's a proper relocation against the jump table entry. 609 if (HasRelocations) { 610 if (Type == JumpTable::JTT_PIC && 611 !DataPCRelocations.count(EntryAddress)) { 612 LLVM_DEBUG( 613 dbgs() << "FAIL: JTT_PIC table, no relocation for this address\n"); 614 break; 615 } 616 if (Type == JumpTable::JTT_NORMAL && !getRelocationAt(EntryAddress)) { 617 LLVM_DEBUG( 618 dbgs() 619 << "FAIL: JTT_NORMAL table, no relocation for this address\n"); 620 break; 621 } 622 } 623 624 const uint64_t Value = 625 (Type == JumpTable::JTT_PIC) 626 ? Address + *getSignedValueAtAddress(EntryAddress, EntrySize) 627 : *getPointerAtAddress(EntryAddress); 628 629 // __builtin_unreachable() case. 630 if (Value == UnreachableAddress) { 631 addEntryAddress(Value, /*Unreachable*/ true); 632 HasUnreachable = true; 633 LLVM_DEBUG(dbgs() << formatv("OK: {0:x} __builtin_unreachable\n", Value)); 634 continue; 635 } 636 637 // Function start is another special case. It is allowed in the jump table, 638 // but we need at least one another regular entry to distinguish the table 639 // from, e.g. a function pointer array. 640 if (Value == BF.getAddress()) { 641 HasStartAsEntry = true; 642 addEntryAddress(Value); 643 continue; 644 } 645 646 // Function or one of its fragments. 647 const BinaryFunction *TargetBF = getBinaryFunctionContainingAddress(Value); 648 const bool DoesBelongToFunction = 649 BF.containsAddress(Value) || 650 (TargetBF && TargetBF->isParentOrChildOf(BF)); 651 if (!DoesBelongToFunction) { 652 LLVM_DEBUG({ 653 if (!BF.containsAddress(Value)) { 654 dbgs() << "FAIL: function doesn't contain this address\n"; 655 if (TargetBF) { 656 dbgs() << " ! function containing this address: " 657 << TargetBF->getPrintName() << '\n'; 658 if (TargetBF->isFragment()) { 659 dbgs() << " ! is a fragment"; 660 for (BinaryFunction *Parent : TargetBF->ParentFragments) 661 dbgs() << ", parent: " << Parent->getPrintName(); 662 dbgs() << '\n'; 663 } 664 } 665 } 666 }); 667 break; 668 } 669 670 // Check there's an instruction at this offset. 671 if (TargetBF->getState() == BinaryFunction::State::Disassembled && 672 !TargetBF->getInstructionAtOffset(Value - TargetBF->getAddress())) { 673 LLVM_DEBUG(dbgs() << formatv("FAIL: no instruction at {0:x}\n", Value)); 674 break; 675 } 676 677 ++NumRealEntries; 678 LLVM_DEBUG(dbgs() << formatv("OK: {0:x} real entry\n", Value)); 679 680 if (TargetBF != &BF && HasEntryInFragment) 681 *HasEntryInFragment = true; 682 addEntryAddress(Value); 683 } 684 685 // Trim direct/normal jump table to exclude trailing unreachable entries that 686 // can collide with a function address. 687 if (Type == JumpTable::JTT_NORMAL && EntriesAsAddress && 688 TrimmedSize != EntriesAsAddress->size() && 689 getBinaryFunctionAtAddress(UnreachableAddress)) 690 EntriesAsAddress->resize(TrimmedSize); 691 692 // It's a jump table if the number of real entries is more than 1, or there's 693 // one real entry and one or more special targets. If there are only multiple 694 // special targets, then it's not a jump table. 695 return NumRealEntries + (HasUnreachable || HasStartAsEntry) >= 2; 696 } 697 698 void BinaryContext::populateJumpTables() { 699 LLVM_DEBUG(dbgs() << "DataPCRelocations: " << DataPCRelocations.size() 700 << '\n'); 701 for (auto JTI = JumpTables.begin(), JTE = JumpTables.end(); JTI != JTE; 702 ++JTI) { 703 JumpTable *JT = JTI->second; 704 705 bool NonSimpleParent = false; 706 for (BinaryFunction *BF : JT->Parents) 707 NonSimpleParent |= !BF->isSimple(); 708 if (NonSimpleParent) 709 continue; 710 711 uint64_t NextJTAddress = 0; 712 auto NextJTI = std::next(JTI); 713 if (NextJTI != JTE) 714 NextJTAddress = NextJTI->second->getAddress(); 715 716 const bool Success = 717 analyzeJumpTable(JT->getAddress(), JT->Type, *(JT->Parents[0]), 718 NextJTAddress, &JT->EntriesAsAddress, &JT->IsSplit); 719 if (!Success) { 720 LLVM_DEBUG({ 721 dbgs() << "failed to analyze "; 722 JT->print(dbgs()); 723 if (NextJTI != JTE) { 724 dbgs() << "next "; 725 NextJTI->second->print(dbgs()); 726 } 727 }); 728 llvm_unreachable("jump table heuristic failure"); 729 } 730 for (BinaryFunction *Frag : JT->Parents) { 731 if (JT->IsSplit) 732 Frag->setHasIndirectTargetToSplitFragment(true); 733 for (uint64_t EntryAddress : JT->EntriesAsAddress) 734 // if target is builtin_unreachable 735 if (EntryAddress == Frag->getAddress() + Frag->getSize()) { 736 Frag->IgnoredBranches.emplace_back(EntryAddress - Frag->getAddress(), 737 Frag->getSize()); 738 } else if (EntryAddress >= Frag->getAddress() && 739 EntryAddress < Frag->getAddress() + Frag->getSize()) { 740 Frag->registerReferencedOffset(EntryAddress - Frag->getAddress()); 741 } 742 } 743 744 // In strict mode, erase PC-relative relocation record. Later we check that 745 // all such records are erased and thus have been accounted for. 746 if (opts::StrictMode && JT->Type == JumpTable::JTT_PIC) { 747 for (uint64_t Address = JT->getAddress(); 748 Address < JT->getAddress() + JT->getSize(); 749 Address += JT->EntrySize) { 750 DataPCRelocations.erase(DataPCRelocations.find(Address)); 751 } 752 } 753 754 // Mark to skip the function and all its fragments. 755 for (BinaryFunction *Frag : JT->Parents) 756 if (Frag->hasIndirectTargetToSplitFragment()) 757 addFragmentsToSkip(Frag); 758 } 759 760 if (opts::StrictMode && DataPCRelocations.size()) { 761 LLVM_DEBUG({ 762 dbgs() << DataPCRelocations.size() 763 << " unclaimed PC-relative relocations left in data:\n"; 764 for (uint64_t Reloc : DataPCRelocations) 765 dbgs() << Twine::utohexstr(Reloc) << '\n'; 766 }); 767 assert(0 && "unclaimed PC-relative relocations left in data\n"); 768 } 769 clearList(DataPCRelocations); 770 } 771 772 void BinaryContext::skipMarkedFragments() { 773 std::vector<BinaryFunction *> FragmentQueue; 774 // Copy the functions to FragmentQueue. 775 FragmentQueue.assign(FragmentsToSkip.begin(), FragmentsToSkip.end()); 776 auto addToWorklist = [&](BinaryFunction *Function) -> void { 777 if (FragmentsToSkip.count(Function)) 778 return; 779 FragmentQueue.push_back(Function); 780 addFragmentsToSkip(Function); 781 }; 782 // Functions containing split jump tables need to be skipped with all 783 // fragments (transitively). 784 for (size_t I = 0; I != FragmentQueue.size(); I++) { 785 BinaryFunction *BF = FragmentQueue[I]; 786 assert(FragmentsToSkip.count(BF) && 787 "internal error in traversing function fragments"); 788 if (opts::Verbosity >= 1) 789 this->errs() << "BOLT-WARNING: Ignoring " << BF->getPrintName() << '\n'; 790 BF->setSimple(false); 791 BF->setHasIndirectTargetToSplitFragment(true); 792 793 llvm::for_each(BF->Fragments, addToWorklist); 794 llvm::for_each(BF->ParentFragments, addToWorklist); 795 } 796 if (!FragmentsToSkip.empty()) 797 this->errs() << "BOLT-WARNING: skipped " << FragmentsToSkip.size() 798 << " function" << (FragmentsToSkip.size() == 1 ? "" : "s") 799 << " due to cold fragments\n"; 800 } 801 802 MCSymbol *BinaryContext::getOrCreateGlobalSymbol(uint64_t Address, Twine Prefix, 803 uint64_t Size, 804 uint16_t Alignment, 805 unsigned Flags) { 806 auto Itr = BinaryDataMap.find(Address); 807 if (Itr != BinaryDataMap.end()) { 808 assert(Itr->second->getSize() == Size || !Size); 809 return Itr->second->getSymbol(); 810 } 811 812 std::string Name = (Prefix + "0x" + Twine::utohexstr(Address)).str(); 813 assert(!GlobalSymbols.count(Name) && "created name is not unique"); 814 return registerNameAtAddress(Name, Address, Size, Alignment, Flags); 815 } 816 817 MCSymbol *BinaryContext::getOrCreateUndefinedGlobalSymbol(StringRef Name) { 818 return Ctx->getOrCreateSymbol(Name); 819 } 820 821 BinaryFunction *BinaryContext::createBinaryFunction( 822 const std::string &Name, BinarySection &Section, uint64_t Address, 823 uint64_t Size, uint64_t SymbolSize, uint16_t Alignment) { 824 auto Result = BinaryFunctions.emplace( 825 Address, BinaryFunction(Name, Section, Address, Size, *this)); 826 assert(Result.second == true && "unexpected duplicate function"); 827 BinaryFunction *BF = &Result.first->second; 828 registerNameAtAddress(Name, Address, SymbolSize ? SymbolSize : Size, 829 Alignment); 830 setSymbolToFunctionMap(BF->getSymbol(), BF); 831 return BF; 832 } 833 834 const MCSymbol * 835 BinaryContext::getOrCreateJumpTable(BinaryFunction &Function, uint64_t Address, 836 JumpTable::JumpTableType Type) { 837 // Two fragments of same function access same jump table 838 if (JumpTable *JT = getJumpTableContainingAddress(Address)) { 839 assert(JT->Type == Type && "jump table types have to match"); 840 assert(Address == JT->getAddress() && "unexpected non-empty jump table"); 841 842 // Prevent associating a jump table to a specific fragment twice. 843 // This simple check arises from the assumption: no more than 2 fragments. 844 if (JT->Parents.size() == 1 && JT->Parents[0] != &Function) { 845 assert(JT->Parents[0]->isParentOrChildOf(Function) && 846 "cannot re-use jump table of a different function"); 847 // Duplicate the entry for the parent function for easy access 848 JT->Parents.push_back(&Function); 849 if (opts::Verbosity > 2) { 850 this->outs() << "BOLT-INFO: Multiple fragments access same jump table: " 851 << JT->Parents[0]->getPrintName() << "; " 852 << Function.getPrintName() << "\n"; 853 JT->print(this->outs()); 854 } 855 Function.JumpTables.emplace(Address, JT); 856 JT->Parents[0]->setHasIndirectTargetToSplitFragment(true); 857 JT->Parents[1]->setHasIndirectTargetToSplitFragment(true); 858 } 859 860 bool IsJumpTableParent = false; 861 (void)IsJumpTableParent; 862 for (BinaryFunction *Frag : JT->Parents) 863 if (Frag == &Function) 864 IsJumpTableParent = true; 865 assert(IsJumpTableParent && 866 "cannot re-use jump table of a different function"); 867 return JT->getFirstLabel(); 868 } 869 870 // Re-use the existing symbol if possible. 871 MCSymbol *JTLabel = nullptr; 872 if (BinaryData *Object = getBinaryDataAtAddress(Address)) { 873 if (!isInternalSymbolName(Object->getSymbol()->getName())) 874 JTLabel = Object->getSymbol(); 875 } 876 877 const uint64_t EntrySize = getJumpTableEntrySize(Type); 878 if (!JTLabel) { 879 const std::string JumpTableName = generateJumpTableName(Function, Address); 880 JTLabel = registerNameAtAddress(JumpTableName, Address, 0, EntrySize); 881 } 882 883 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: creating jump table " << JTLabel->getName() 884 << " in function " << Function << '\n'); 885 886 JumpTable *JT = new JumpTable(*JTLabel, Address, EntrySize, Type, 887 JumpTable::LabelMapType{{0, JTLabel}}, 888 *getSectionForAddress(Address)); 889 JT->Parents.push_back(&Function); 890 if (opts::Verbosity > 2) 891 JT->print(this->outs()); 892 JumpTables.emplace(Address, JT); 893 894 // Duplicate the entry for the parent function for easy access. 895 Function.JumpTables.emplace(Address, JT); 896 return JTLabel; 897 } 898 899 std::pair<uint64_t, const MCSymbol *> 900 BinaryContext::duplicateJumpTable(BinaryFunction &Function, JumpTable *JT, 901 const MCSymbol *OldLabel) { 902 auto L = scopeLock(); 903 unsigned Offset = 0; 904 bool Found = false; 905 for (std::pair<const unsigned, MCSymbol *> Elmt : JT->Labels) { 906 if (Elmt.second != OldLabel) 907 continue; 908 Offset = Elmt.first; 909 Found = true; 910 break; 911 } 912 assert(Found && "Label not found"); 913 (void)Found; 914 MCSymbol *NewLabel = Ctx->createNamedTempSymbol("duplicatedJT"); 915 JumpTable *NewJT = 916 new JumpTable(*NewLabel, JT->getAddress(), JT->EntrySize, JT->Type, 917 JumpTable::LabelMapType{{Offset, NewLabel}}, 918 *getSectionForAddress(JT->getAddress())); 919 NewJT->Parents = JT->Parents; 920 NewJT->Entries = JT->Entries; 921 NewJT->Counts = JT->Counts; 922 uint64_t JumpTableID = ++DuplicatedJumpTables; 923 // Invert it to differentiate from regular jump tables whose IDs are their 924 // addresses in the input binary memory space 925 JumpTableID = ~JumpTableID; 926 JumpTables.emplace(JumpTableID, NewJT); 927 Function.JumpTables.emplace(JumpTableID, NewJT); 928 return std::make_pair(JumpTableID, NewLabel); 929 } 930 931 std::string BinaryContext::generateJumpTableName(const BinaryFunction &BF, 932 uint64_t Address) { 933 size_t Id; 934 uint64_t Offset = 0; 935 if (const JumpTable *JT = BF.getJumpTableContainingAddress(Address)) { 936 Offset = Address - JT->getAddress(); 937 auto Itr = JT->Labels.find(Offset); 938 if (Itr != JT->Labels.end()) 939 return std::string(Itr->second->getName()); 940 Id = JumpTableIds.at(JT->getAddress()); 941 } else { 942 Id = JumpTableIds[Address] = BF.JumpTables.size(); 943 } 944 return ("JUMP_TABLE/" + BF.getOneName().str() + "." + std::to_string(Id) + 945 (Offset ? ("." + std::to_string(Offset)) : "")); 946 } 947 948 bool BinaryContext::hasValidCodePadding(const BinaryFunction &BF) { 949 // FIXME: aarch64 support is missing. 950 if (!isX86()) 951 return true; 952 953 if (BF.getSize() == BF.getMaxSize()) 954 return true; 955 956 ErrorOr<ArrayRef<unsigned char>> FunctionData = BF.getData(); 957 assert(FunctionData && "cannot get function as data"); 958 959 uint64_t Offset = BF.getSize(); 960 MCInst Instr; 961 uint64_t InstrSize = 0; 962 uint64_t InstrAddress = BF.getAddress() + Offset; 963 using std::placeholders::_1; 964 965 // Skip instructions that satisfy the predicate condition. 966 auto skipInstructions = [&](std::function<bool(const MCInst &)> Predicate) { 967 const uint64_t StartOffset = Offset; 968 for (; Offset < BF.getMaxSize(); 969 Offset += InstrSize, InstrAddress += InstrSize) { 970 if (!DisAsm->getInstruction(Instr, InstrSize, FunctionData->slice(Offset), 971 InstrAddress, nulls())) 972 break; 973 if (!Predicate(Instr)) 974 break; 975 } 976 977 return Offset - StartOffset; 978 }; 979 980 // Skip a sequence of zero bytes. 981 auto skipZeros = [&]() { 982 const uint64_t StartOffset = Offset; 983 for (; Offset < BF.getMaxSize(); ++Offset) 984 if ((*FunctionData)[Offset] != 0) 985 break; 986 987 return Offset - StartOffset; 988 }; 989 990 // Accept the whole padding area filled with breakpoints. 991 auto isBreakpoint = std::bind(&MCPlusBuilder::isBreakpoint, MIB.get(), _1); 992 if (skipInstructions(isBreakpoint) && Offset == BF.getMaxSize()) 993 return true; 994 995 auto isNoop = std::bind(&MCPlusBuilder::isNoop, MIB.get(), _1); 996 997 // Some functions have a jump to the next function or to the padding area 998 // inserted after the body. 999 auto isSkipJump = [&](const MCInst &Instr) { 1000 uint64_t TargetAddress = 0; 1001 if (MIB->isUnconditionalBranch(Instr) && 1002 MIB->evaluateBranch(Instr, InstrAddress, InstrSize, TargetAddress)) { 1003 if (TargetAddress >= InstrAddress + InstrSize && 1004 TargetAddress <= BF.getAddress() + BF.getMaxSize()) { 1005 return true; 1006 } 1007 } 1008 return false; 1009 }; 1010 1011 // Skip over nops, jumps, and zero padding. Allow interleaving (this happens). 1012 while (skipInstructions(isNoop) || skipInstructions(isSkipJump) || 1013 skipZeros()) 1014 ; 1015 1016 if (Offset == BF.getMaxSize()) 1017 return true; 1018 1019 if (opts::Verbosity >= 1) { 1020 this->errs() << "BOLT-WARNING: bad padding at address 0x" 1021 << Twine::utohexstr(BF.getAddress() + BF.getSize()) 1022 << " starting at offset " << (Offset - BF.getSize()) 1023 << " in function " << BF << '\n' 1024 << FunctionData->slice(BF.getSize(), 1025 BF.getMaxSize() - BF.getSize()) 1026 << '\n'; 1027 } 1028 1029 return false; 1030 } 1031 1032 void BinaryContext::adjustCodePadding() { 1033 for (auto &BFI : BinaryFunctions) { 1034 BinaryFunction &BF = BFI.second; 1035 if (!shouldEmit(BF)) 1036 continue; 1037 1038 if (!hasValidCodePadding(BF)) { 1039 if (HasRelocations) { 1040 if (opts::Verbosity >= 1) { 1041 this->outs() << "BOLT-INFO: function " << BF 1042 << " has invalid padding. Ignoring the function.\n"; 1043 } 1044 BF.setIgnored(); 1045 } else { 1046 BF.setMaxSize(BF.getSize()); 1047 } 1048 } 1049 } 1050 } 1051 1052 MCSymbol *BinaryContext::registerNameAtAddress(StringRef Name, uint64_t Address, 1053 uint64_t Size, 1054 uint16_t Alignment, 1055 unsigned Flags) { 1056 // Register the name with MCContext. 1057 MCSymbol *Symbol = Ctx->getOrCreateSymbol(Name); 1058 1059 auto GAI = BinaryDataMap.find(Address); 1060 BinaryData *BD; 1061 if (GAI == BinaryDataMap.end()) { 1062 ErrorOr<BinarySection &> SectionOrErr = getSectionForAddress(Address); 1063 BinarySection &Section = 1064 SectionOrErr ? SectionOrErr.get() : absoluteSection(); 1065 BD = new BinaryData(*Symbol, Address, Size, Alignment ? Alignment : 1, 1066 Section, Flags); 1067 GAI = BinaryDataMap.emplace(Address, BD).first; 1068 GlobalSymbols[Name] = BD; 1069 updateObjectNesting(GAI); 1070 } else { 1071 BD = GAI->second; 1072 if (!BD->hasName(Name)) { 1073 GlobalSymbols[Name] = BD; 1074 BD->Symbols.push_back(Symbol); 1075 } 1076 } 1077 1078 return Symbol; 1079 } 1080 1081 const BinaryData * 1082 BinaryContext::getBinaryDataContainingAddressImpl(uint64_t Address) const { 1083 auto NI = BinaryDataMap.lower_bound(Address); 1084 auto End = BinaryDataMap.end(); 1085 if ((NI != End && Address == NI->first) || 1086 ((NI != BinaryDataMap.begin()) && (NI-- != BinaryDataMap.begin()))) { 1087 if (NI->second->containsAddress(Address)) 1088 return NI->second; 1089 1090 // If this is a sub-symbol, see if a parent data contains the address. 1091 const BinaryData *BD = NI->second->getParent(); 1092 while (BD) { 1093 if (BD->containsAddress(Address)) 1094 return BD; 1095 BD = BD->getParent(); 1096 } 1097 } 1098 return nullptr; 1099 } 1100 1101 BinaryData *BinaryContext::getGOTSymbol() { 1102 // First tries to find a global symbol with that name 1103 BinaryData *GOTSymBD = getBinaryDataByName("_GLOBAL_OFFSET_TABLE_"); 1104 if (GOTSymBD) 1105 return GOTSymBD; 1106 1107 // This symbol might be hidden from run-time link, so fetch the local 1108 // definition if available. 1109 GOTSymBD = getBinaryDataByName("_GLOBAL_OFFSET_TABLE_/1"); 1110 if (!GOTSymBD) 1111 return nullptr; 1112 1113 // If the local symbol is not unique, fail 1114 unsigned Index = 2; 1115 SmallString<30> Storage; 1116 while (const BinaryData *BD = 1117 getBinaryDataByName(Twine("_GLOBAL_OFFSET_TABLE_/") 1118 .concat(Twine(Index++)) 1119 .toStringRef(Storage))) 1120 if (BD->getAddress() != GOTSymBD->getAddress()) 1121 return nullptr; 1122 1123 return GOTSymBD; 1124 } 1125 1126 bool BinaryContext::setBinaryDataSize(uint64_t Address, uint64_t Size) { 1127 auto NI = BinaryDataMap.find(Address); 1128 assert(NI != BinaryDataMap.end()); 1129 if (NI == BinaryDataMap.end()) 1130 return false; 1131 // TODO: it's possible that a jump table starts at the same address 1132 // as a larger blob of private data. When we set the size of the 1133 // jump table, it might be smaller than the total blob size. In this 1134 // case we just leave the original size since (currently) it won't really 1135 // affect anything. 1136 assert((!NI->second->Size || NI->second->Size == Size || 1137 (NI->second->isJumpTable() && NI->second->Size > Size)) && 1138 "can't change the size of a symbol that has already had its " 1139 "size set"); 1140 if (!NI->second->Size) { 1141 NI->second->Size = Size; 1142 updateObjectNesting(NI); 1143 return true; 1144 } 1145 return false; 1146 } 1147 1148 void BinaryContext::generateSymbolHashes() { 1149 auto isPadding = [](const BinaryData &BD) { 1150 StringRef Contents = BD.getSection().getContents(); 1151 StringRef SymData = Contents.substr(BD.getOffset(), BD.getSize()); 1152 return (BD.getName().starts_with("HOLEat") || 1153 SymData.find_first_not_of(0) == StringRef::npos); 1154 }; 1155 1156 uint64_t NumCollisions = 0; 1157 for (auto &Entry : BinaryDataMap) { 1158 BinaryData &BD = *Entry.second; 1159 StringRef Name = BD.getName(); 1160 1161 if (!isInternalSymbolName(Name)) 1162 continue; 1163 1164 // First check if a non-anonymous alias exists and move it to the front. 1165 if (BD.getSymbols().size() > 1) { 1166 auto Itr = llvm::find_if(BD.getSymbols(), [&](const MCSymbol *Symbol) { 1167 return !isInternalSymbolName(Symbol->getName()); 1168 }); 1169 if (Itr != BD.getSymbols().end()) { 1170 size_t Idx = std::distance(BD.getSymbols().begin(), Itr); 1171 std::swap(BD.getSymbols()[0], BD.getSymbols()[Idx]); 1172 continue; 1173 } 1174 } 1175 1176 // We have to skip 0 size symbols since they will all collide. 1177 if (BD.getSize() == 0) { 1178 continue; 1179 } 1180 1181 const uint64_t Hash = BD.getSection().hash(BD); 1182 const size_t Idx = Name.find("0x"); 1183 std::string NewName = 1184 (Twine(Name.substr(0, Idx)) + "_" + Twine::utohexstr(Hash)).str(); 1185 if (getBinaryDataByName(NewName)) { 1186 // Ignore collisions for symbols that appear to be padding 1187 // (i.e. all zeros or a "hole") 1188 if (!isPadding(BD)) { 1189 if (opts::Verbosity) { 1190 this->errs() << "BOLT-WARNING: collision detected when hashing " << BD 1191 << " with new name (" << NewName << "), skipping.\n"; 1192 } 1193 ++NumCollisions; 1194 } 1195 continue; 1196 } 1197 BD.Symbols.insert(BD.Symbols.begin(), Ctx->getOrCreateSymbol(NewName)); 1198 GlobalSymbols[NewName] = &BD; 1199 } 1200 if (NumCollisions) { 1201 this->errs() << "BOLT-WARNING: " << NumCollisions 1202 << " collisions detected while hashing binary objects"; 1203 if (!opts::Verbosity) 1204 this->errs() << ". Use -v=1 to see the list."; 1205 this->errs() << '\n'; 1206 } 1207 } 1208 1209 bool BinaryContext::registerFragment(BinaryFunction &TargetFunction, 1210 BinaryFunction &Function) const { 1211 assert(TargetFunction.isFragment() && "TargetFunction must be a fragment"); 1212 if (TargetFunction.isChildOf(Function)) 1213 return true; 1214 TargetFunction.addParentFragment(Function); 1215 Function.addFragment(TargetFunction); 1216 if (!HasRelocations) { 1217 TargetFunction.setSimple(false); 1218 Function.setSimple(false); 1219 } 1220 if (opts::Verbosity >= 1) { 1221 this->outs() << "BOLT-INFO: marking " << TargetFunction 1222 << " as a fragment of " << Function << '\n'; 1223 } 1224 return true; 1225 } 1226 1227 void BinaryContext::addAdrpAddRelocAArch64(BinaryFunction &BF, 1228 MCInst &LoadLowBits, 1229 MCInst &LoadHiBits, 1230 uint64_t Target) { 1231 const MCSymbol *TargetSymbol; 1232 uint64_t Addend = 0; 1233 std::tie(TargetSymbol, Addend) = handleAddressRef(Target, BF, 1234 /*IsPCRel*/ true); 1235 int64_t Val; 1236 MIB->replaceImmWithSymbolRef(LoadHiBits, TargetSymbol, Addend, Ctx.get(), Val, 1237 ELF::R_AARCH64_ADR_PREL_PG_HI21); 1238 MIB->replaceImmWithSymbolRef(LoadLowBits, TargetSymbol, Addend, Ctx.get(), 1239 Val, ELF::R_AARCH64_ADD_ABS_LO12_NC); 1240 } 1241 1242 bool BinaryContext::handleAArch64Veneer(uint64_t Address, bool MatchOnly) { 1243 BinaryFunction *TargetFunction = getBinaryFunctionContainingAddress(Address); 1244 if (TargetFunction) 1245 return false; 1246 1247 ErrorOr<BinarySection &> Section = getSectionForAddress(Address); 1248 assert(Section && "cannot get section for referenced address"); 1249 if (!Section->isText()) 1250 return false; 1251 1252 bool Ret = false; 1253 StringRef SectionContents = Section->getContents(); 1254 uint64_t Offset = Address - Section->getAddress(); 1255 const uint64_t MaxSize = SectionContents.size() - Offset; 1256 const uint8_t *Bytes = 1257 reinterpret_cast<const uint8_t *>(SectionContents.data()); 1258 ArrayRef<uint8_t> Data(Bytes + Offset, MaxSize); 1259 1260 auto matchVeneer = [&](BinaryFunction::InstrMapType &Instructions, 1261 MCInst &Instruction, uint64_t Offset, 1262 uint64_t AbsoluteInstrAddr, 1263 uint64_t TotalSize) -> bool { 1264 MCInst *TargetHiBits, *TargetLowBits; 1265 uint64_t TargetAddress, Count; 1266 Count = MIB->matchLinkerVeneer(Instructions.begin(), Instructions.end(), 1267 AbsoluteInstrAddr, Instruction, TargetHiBits, 1268 TargetLowBits, TargetAddress); 1269 if (!Count) 1270 return false; 1271 1272 if (MatchOnly) 1273 return true; 1274 1275 // NOTE The target symbol was created during disassemble's 1276 // handleExternalReference 1277 const MCSymbol *VeneerSymbol = getOrCreateGlobalSymbol(Address, "FUNCat"); 1278 BinaryFunction *Veneer = createBinaryFunction(VeneerSymbol->getName().str(), 1279 *Section, Address, TotalSize); 1280 addAdrpAddRelocAArch64(*Veneer, *TargetLowBits, *TargetHiBits, 1281 TargetAddress); 1282 MIB->addAnnotation(Instruction, "AArch64Veneer", true); 1283 Veneer->addInstruction(Offset, std::move(Instruction)); 1284 --Count; 1285 for (auto It = Instructions.rbegin(); Count != 0; ++It, --Count) { 1286 MIB->addAnnotation(It->second, "AArch64Veneer", true); 1287 Veneer->addInstruction(It->first, std::move(It->second)); 1288 } 1289 1290 Veneer->getOrCreateLocalLabel(Address); 1291 Veneer->setMaxSize(TotalSize); 1292 Veneer->updateState(BinaryFunction::State::Disassembled); 1293 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: handling veneer function at 0x" << Address 1294 << "\n"); 1295 return true; 1296 }; 1297 1298 uint64_t Size = 0, TotalSize = 0; 1299 BinaryFunction::InstrMapType VeneerInstructions; 1300 for (Offset = 0; Offset < MaxSize; Offset += Size) { 1301 MCInst Instruction; 1302 const uint64_t AbsoluteInstrAddr = Address + Offset; 1303 if (!SymbolicDisAsm->getInstruction(Instruction, Size, Data.slice(Offset), 1304 AbsoluteInstrAddr, nulls())) 1305 break; 1306 1307 TotalSize += Size; 1308 if (MIB->isBranch(Instruction)) { 1309 Ret = matchVeneer(VeneerInstructions, Instruction, Offset, 1310 AbsoluteInstrAddr, TotalSize); 1311 break; 1312 } 1313 1314 VeneerInstructions.emplace(Offset, std::move(Instruction)); 1315 } 1316 1317 return Ret; 1318 } 1319 1320 void BinaryContext::processInterproceduralReferences() { 1321 for (const std::pair<BinaryFunction *, uint64_t> &It : 1322 InterproceduralReferences) { 1323 BinaryFunction &Function = *It.first; 1324 uint64_t Address = It.second; 1325 if (!Address || Function.isIgnored()) 1326 continue; 1327 1328 BinaryFunction *TargetFunction = 1329 getBinaryFunctionContainingAddress(Address); 1330 if (&Function == TargetFunction) 1331 continue; 1332 1333 if (TargetFunction) { 1334 if (TargetFunction->isFragment() && 1335 !TargetFunction->isChildOf(Function)) { 1336 this->errs() 1337 << "BOLT-WARNING: interprocedural reference between unrelated " 1338 "fragments: " 1339 << Function.getPrintName() << " and " 1340 << TargetFunction->getPrintName() << '\n'; 1341 } 1342 if (uint64_t Offset = Address - TargetFunction->getAddress()) 1343 TargetFunction->addEntryPointAtOffset(Offset); 1344 1345 continue; 1346 } 1347 1348 // Check if address falls in function padding space - this could be 1349 // unmarked data in code. In this case adjust the padding space size. 1350 ErrorOr<BinarySection &> Section = getSectionForAddress(Address); 1351 assert(Section && "cannot get section for referenced address"); 1352 1353 if (!Section->isText()) 1354 continue; 1355 1356 // PLT requires special handling and could be ignored in this context. 1357 StringRef SectionName = Section->getName(); 1358 if (SectionName == ".plt" || SectionName == ".plt.got") 1359 continue; 1360 1361 // Check if it is aarch64 veneer written at Address 1362 if (isAArch64() && handleAArch64Veneer(Address)) 1363 continue; 1364 1365 if (opts::processAllFunctions()) { 1366 this->errs() << "BOLT-ERROR: cannot process binaries with unmarked " 1367 << "object in code at address 0x" 1368 << Twine::utohexstr(Address) << " belonging to section " 1369 << SectionName << " in current mode\n"; 1370 exit(1); 1371 } 1372 1373 TargetFunction = getBinaryFunctionContainingAddress(Address, 1374 /*CheckPastEnd=*/false, 1375 /*UseMaxSize=*/true); 1376 // We are not going to overwrite non-simple functions, but for simple 1377 // ones - adjust the padding size. 1378 if (TargetFunction && TargetFunction->isSimple()) { 1379 this->errs() 1380 << "BOLT-WARNING: function " << *TargetFunction 1381 << " has an object detected in a padding region at address 0x" 1382 << Twine::utohexstr(Address) << '\n'; 1383 TargetFunction->setMaxSize(TargetFunction->getSize()); 1384 } 1385 } 1386 1387 InterproceduralReferences.clear(); 1388 } 1389 1390 void BinaryContext::postProcessSymbolTable() { 1391 fixBinaryDataHoles(); 1392 bool Valid = true; 1393 for (auto &Entry : BinaryDataMap) { 1394 BinaryData *BD = Entry.second; 1395 if ((BD->getName().starts_with("SYMBOLat") || 1396 BD->getName().starts_with("DATAat")) && 1397 !BD->getParent() && !BD->getSize() && !BD->isAbsolute() && 1398 BD->getSection()) { 1399 this->errs() << "BOLT-WARNING: zero-sized top level symbol: " << *BD 1400 << "\n"; 1401 Valid = false; 1402 } 1403 } 1404 assert(Valid); 1405 (void)Valid; 1406 generateSymbolHashes(); 1407 } 1408 1409 void BinaryContext::foldFunction(BinaryFunction &ChildBF, 1410 BinaryFunction &ParentBF) { 1411 assert(!ChildBF.isMultiEntry() && !ParentBF.isMultiEntry() && 1412 "cannot merge functions with multiple entry points"); 1413 1414 std::unique_lock<llvm::sys::RWMutex> WriteCtxLock(CtxMutex, std::defer_lock); 1415 std::unique_lock<llvm::sys::RWMutex> WriteSymbolMapLock( 1416 SymbolToFunctionMapMutex, std::defer_lock); 1417 1418 const StringRef ChildName = ChildBF.getOneName(); 1419 1420 // Move symbols over and update bookkeeping info. 1421 for (MCSymbol *Symbol : ChildBF.getSymbols()) { 1422 ParentBF.getSymbols().push_back(Symbol); 1423 WriteSymbolMapLock.lock(); 1424 SymbolToFunctionMap[Symbol] = &ParentBF; 1425 WriteSymbolMapLock.unlock(); 1426 // NB: there's no need to update BinaryDataMap and GlobalSymbols. 1427 } 1428 ChildBF.getSymbols().clear(); 1429 1430 // Move other names the child function is known under. 1431 llvm::move(ChildBF.Aliases, std::back_inserter(ParentBF.Aliases)); 1432 ChildBF.Aliases.clear(); 1433 1434 if (HasRelocations) { 1435 // Merge execution counts of ChildBF into those of ParentBF. 1436 // Without relocations, we cannot reliably merge profiles as both functions 1437 // continue to exist and either one can be executed. 1438 ChildBF.mergeProfileDataInto(ParentBF); 1439 1440 std::shared_lock<llvm::sys::RWMutex> ReadBfsLock(BinaryFunctionsMutex, 1441 std::defer_lock); 1442 std::unique_lock<llvm::sys::RWMutex> WriteBfsLock(BinaryFunctionsMutex, 1443 std::defer_lock); 1444 // Remove ChildBF from the global set of functions in relocs mode. 1445 ReadBfsLock.lock(); 1446 auto FI = BinaryFunctions.find(ChildBF.getAddress()); 1447 ReadBfsLock.unlock(); 1448 1449 assert(FI != BinaryFunctions.end() && "function not found"); 1450 assert(&ChildBF == &FI->second && "function mismatch"); 1451 1452 WriteBfsLock.lock(); 1453 ChildBF.clearDisasmState(); 1454 FI = BinaryFunctions.erase(FI); 1455 WriteBfsLock.unlock(); 1456 1457 } else { 1458 // In non-relocation mode we keep the function, but rename it. 1459 std::string NewName = "__ICF_" + ChildName.str(); 1460 1461 WriteCtxLock.lock(); 1462 ChildBF.getSymbols().push_back(Ctx->getOrCreateSymbol(NewName)); 1463 WriteCtxLock.unlock(); 1464 1465 ChildBF.setFolded(&ParentBF); 1466 } 1467 1468 ParentBF.setHasFunctionsFoldedInto(); 1469 } 1470 1471 void BinaryContext::fixBinaryDataHoles() { 1472 assert(validateObjectNesting() && "object nesting inconsistency detected"); 1473 1474 for (BinarySection &Section : allocatableSections()) { 1475 std::vector<std::pair<uint64_t, uint64_t>> Holes; 1476 1477 auto isNotHole = [&Section](const binary_data_iterator &Itr) { 1478 BinaryData *BD = Itr->second; 1479 bool isHole = (!BD->getParent() && !BD->getSize() && BD->isObject() && 1480 (BD->getName().starts_with("SYMBOLat0x") || 1481 BD->getName().starts_with("DATAat0x") || 1482 BD->getName().starts_with("ANONYMOUS"))); 1483 return !isHole && BD->getSection() == Section && !BD->getParent(); 1484 }; 1485 1486 auto BDStart = BinaryDataMap.begin(); 1487 auto BDEnd = BinaryDataMap.end(); 1488 auto Itr = FilteredBinaryDataIterator(isNotHole, BDStart, BDEnd); 1489 auto End = FilteredBinaryDataIterator(isNotHole, BDEnd, BDEnd); 1490 1491 uint64_t EndAddress = Section.getAddress(); 1492 1493 while (Itr != End) { 1494 if (Itr->second->getAddress() > EndAddress) { 1495 uint64_t Gap = Itr->second->getAddress() - EndAddress; 1496 Holes.emplace_back(EndAddress, Gap); 1497 } 1498 EndAddress = Itr->second->getEndAddress(); 1499 ++Itr; 1500 } 1501 1502 if (EndAddress < Section.getEndAddress()) 1503 Holes.emplace_back(EndAddress, Section.getEndAddress() - EndAddress); 1504 1505 // If there is already a symbol at the start of the hole, grow that symbol 1506 // to cover the rest. Otherwise, create a new symbol to cover the hole. 1507 for (std::pair<uint64_t, uint64_t> &Hole : Holes) { 1508 BinaryData *BD = getBinaryDataAtAddress(Hole.first); 1509 if (BD) { 1510 // BD->getSection() can be != Section if there are sections that 1511 // overlap. In this case it is probably safe to just skip the holes 1512 // since the overlapping section will not(?) have any symbols in it. 1513 if (BD->getSection() == Section) 1514 setBinaryDataSize(Hole.first, Hole.second); 1515 } else { 1516 getOrCreateGlobalSymbol(Hole.first, "HOLEat", Hole.second, 1); 1517 } 1518 } 1519 } 1520 1521 assert(validateObjectNesting() && "object nesting inconsistency detected"); 1522 assert(validateHoles() && "top level hole detected in object map"); 1523 } 1524 1525 void BinaryContext::printGlobalSymbols(raw_ostream &OS) const { 1526 const BinarySection *CurrentSection = nullptr; 1527 bool FirstSection = true; 1528 1529 for (auto &Entry : BinaryDataMap) { 1530 const BinaryData *BD = Entry.second; 1531 const BinarySection &Section = BD->getSection(); 1532 if (FirstSection || Section != *CurrentSection) { 1533 uint64_t Address, Size; 1534 StringRef Name = Section.getName(); 1535 if (Section) { 1536 Address = Section.getAddress(); 1537 Size = Section.getSize(); 1538 } else { 1539 Address = BD->getAddress(); 1540 Size = BD->getSize(); 1541 } 1542 OS << "BOLT-INFO: Section " << Name << ", " 1543 << "0x" + Twine::utohexstr(Address) << ":" 1544 << "0x" + Twine::utohexstr(Address + Size) << "/" << Size << "\n"; 1545 CurrentSection = &Section; 1546 FirstSection = false; 1547 } 1548 1549 OS << "BOLT-INFO: "; 1550 const BinaryData *P = BD->getParent(); 1551 while (P) { 1552 OS << " "; 1553 P = P->getParent(); 1554 } 1555 OS << *BD << "\n"; 1556 } 1557 } 1558 1559 Expected<unsigned> BinaryContext::getDwarfFile( 1560 StringRef Directory, StringRef FileName, unsigned FileNumber, 1561 std::optional<MD5::MD5Result> Checksum, std::optional<StringRef> Source, 1562 unsigned CUID, unsigned DWARFVersion) { 1563 DwarfLineTable &Table = DwarfLineTablesCUMap[CUID]; 1564 return Table.tryGetFile(Directory, FileName, Checksum, Source, DWARFVersion, 1565 FileNumber); 1566 } 1567 1568 unsigned BinaryContext::addDebugFilenameToUnit(const uint32_t DestCUID, 1569 const uint32_t SrcCUID, 1570 unsigned FileIndex) { 1571 DWARFCompileUnit *SrcUnit = DwCtx->getCompileUnitForOffset(SrcCUID); 1572 const DWARFDebugLine::LineTable *LineTable = 1573 DwCtx->getLineTableForUnit(SrcUnit); 1574 const std::vector<DWARFDebugLine::FileNameEntry> &FileNames = 1575 LineTable->Prologue.FileNames; 1576 // Dir indexes start at 1, as DWARF file numbers, and a dir index 0 1577 // means empty dir. 1578 assert(FileIndex > 0 && FileIndex <= FileNames.size() && 1579 "FileIndex out of range for the compilation unit."); 1580 StringRef Dir = ""; 1581 if (FileNames[FileIndex - 1].DirIdx != 0) { 1582 if (std::optional<const char *> DirName = dwarf::toString( 1583 LineTable->Prologue 1584 .IncludeDirectories[FileNames[FileIndex - 1].DirIdx - 1])) { 1585 Dir = *DirName; 1586 } 1587 } 1588 StringRef FileName = ""; 1589 if (std::optional<const char *> FName = 1590 dwarf::toString(FileNames[FileIndex - 1].Name)) 1591 FileName = *FName; 1592 assert(FileName != ""); 1593 DWARFCompileUnit *DstUnit = DwCtx->getCompileUnitForOffset(DestCUID); 1594 return cantFail(getDwarfFile(Dir, FileName, 0, std::nullopt, std::nullopt, 1595 DestCUID, DstUnit->getVersion())); 1596 } 1597 1598 std::vector<BinaryFunction *> BinaryContext::getSortedFunctions() { 1599 std::vector<BinaryFunction *> SortedFunctions(BinaryFunctions.size()); 1600 llvm::transform(llvm::make_second_range(BinaryFunctions), 1601 SortedFunctions.begin(), 1602 [](BinaryFunction &BF) { return &BF; }); 1603 1604 llvm::stable_sort(SortedFunctions, 1605 [](const BinaryFunction *A, const BinaryFunction *B) { 1606 if (A->hasValidIndex() && B->hasValidIndex()) { 1607 return A->getIndex() < B->getIndex(); 1608 } 1609 return A->hasValidIndex(); 1610 }); 1611 return SortedFunctions; 1612 } 1613 1614 std::vector<BinaryFunction *> BinaryContext::getAllBinaryFunctions() { 1615 std::vector<BinaryFunction *> AllFunctions; 1616 AllFunctions.reserve(BinaryFunctions.size() + InjectedBinaryFunctions.size()); 1617 llvm::transform(llvm::make_second_range(BinaryFunctions), 1618 std::back_inserter(AllFunctions), 1619 [](BinaryFunction &BF) { return &BF; }); 1620 llvm::copy(InjectedBinaryFunctions, std::back_inserter(AllFunctions)); 1621 1622 return AllFunctions; 1623 } 1624 1625 std::optional<DWARFUnit *> BinaryContext::getDWOCU(uint64_t DWOId) { 1626 auto Iter = DWOCUs.find(DWOId); 1627 if (Iter == DWOCUs.end()) 1628 return std::nullopt; 1629 1630 return Iter->second; 1631 } 1632 1633 DWARFContext *BinaryContext::getDWOContext() const { 1634 if (DWOCUs.empty()) 1635 return nullptr; 1636 return &DWOCUs.begin()->second->getContext(); 1637 } 1638 1639 /// Handles DWO sections that can either be in .o, .dwo or .dwp files. 1640 void BinaryContext::preprocessDWODebugInfo() { 1641 for (const std::unique_ptr<DWARFUnit> &CU : DwCtx->compile_units()) { 1642 DWARFUnit *const DwarfUnit = CU.get(); 1643 if (std::optional<uint64_t> DWOId = DwarfUnit->getDWOId()) { 1644 std::string DWOName = dwarf::toString( 1645 DwarfUnit->getUnitDIE().find( 1646 {dwarf::DW_AT_dwo_name, dwarf::DW_AT_GNU_dwo_name}), 1647 ""); 1648 SmallString<16> AbsolutePath; 1649 if (!opts::CompDirOverride.empty()) { 1650 sys::path::append(AbsolutePath, opts::CompDirOverride); 1651 sys::path::append(AbsolutePath, DWOName); 1652 } 1653 DWARFUnit *DWOCU = 1654 DwarfUnit->getNonSkeletonUnitDIE(false, AbsolutePath).getDwarfUnit(); 1655 if (!DWOCU->isDWOUnit()) { 1656 this->outs() 1657 << "BOLT-WARNING: Debug Fission: DWO debug information for " 1658 << DWOName 1659 << " was not retrieved and won't be updated. Please check " 1660 "relative path.\n"; 1661 continue; 1662 } 1663 DWOCUs[*DWOId] = DWOCU; 1664 } 1665 } 1666 if (!DWOCUs.empty()) 1667 this->outs() << "BOLT-INFO: processing split DWARF\n"; 1668 } 1669 1670 void BinaryContext::preprocessDebugInfo() { 1671 struct CURange { 1672 uint64_t LowPC; 1673 uint64_t HighPC; 1674 DWARFUnit *Unit; 1675 1676 bool operator<(const CURange &Other) const { return LowPC < Other.LowPC; } 1677 }; 1678 1679 // Building a map of address ranges to CUs similar to .debug_aranges and use 1680 // it to assign CU to functions. 1681 std::vector<CURange> AllRanges; 1682 AllRanges.reserve(DwCtx->getNumCompileUnits()); 1683 for (const std::unique_ptr<DWARFUnit> &CU : DwCtx->compile_units()) { 1684 Expected<DWARFAddressRangesVector> RangesOrError = 1685 CU->getUnitDIE().getAddressRanges(); 1686 if (!RangesOrError) { 1687 consumeError(RangesOrError.takeError()); 1688 continue; 1689 } 1690 for (DWARFAddressRange &Range : *RangesOrError) { 1691 // Parts of the debug info could be invalidated due to corresponding code 1692 // being removed from the binary by the linker. Hence we check if the 1693 // address is a valid one. 1694 if (containsAddress(Range.LowPC)) 1695 AllRanges.emplace_back(CURange{Range.LowPC, Range.HighPC, CU.get()}); 1696 } 1697 1698 ContainsDwarf5 |= CU->getVersion() >= 5; 1699 ContainsDwarfLegacy |= CU->getVersion() < 5; 1700 } 1701 1702 llvm::sort(AllRanges); 1703 for (auto &KV : BinaryFunctions) { 1704 const uint64_t FunctionAddress = KV.first; 1705 BinaryFunction &Function = KV.second; 1706 1707 auto It = llvm::partition_point( 1708 AllRanges, [=](CURange R) { return R.HighPC <= FunctionAddress; }); 1709 if (It != AllRanges.end() && It->LowPC <= FunctionAddress) 1710 Function.setDWARFUnit(It->Unit); 1711 } 1712 1713 // Discover units with debug info that needs to be updated. 1714 for (const auto &KV : BinaryFunctions) { 1715 const BinaryFunction &BF = KV.second; 1716 if (shouldEmit(BF) && BF.getDWARFUnit()) 1717 ProcessedCUs.insert(BF.getDWARFUnit()); 1718 } 1719 1720 // Clear debug info for functions from units that we are not going to process. 1721 for (auto &KV : BinaryFunctions) { 1722 BinaryFunction &BF = KV.second; 1723 if (BF.getDWARFUnit() && !ProcessedCUs.count(BF.getDWARFUnit())) 1724 BF.setDWARFUnit(nullptr); 1725 } 1726 1727 if (opts::Verbosity >= 1) { 1728 this->outs() << "BOLT-INFO: " << ProcessedCUs.size() << " out of " 1729 << DwCtx->getNumCompileUnits() << " CUs will be updated\n"; 1730 } 1731 1732 preprocessDWODebugInfo(); 1733 1734 // Populate MCContext with DWARF files from all units. 1735 StringRef GlobalPrefix = AsmInfo->getPrivateGlobalPrefix(); 1736 for (const std::unique_ptr<DWARFUnit> &CU : DwCtx->compile_units()) { 1737 const uint64_t CUID = CU->getOffset(); 1738 DwarfLineTable &BinaryLineTable = getDwarfLineTable(CUID); 1739 BinaryLineTable.setLabel(Ctx->getOrCreateSymbol( 1740 GlobalPrefix + "line_table_start" + Twine(CUID))); 1741 1742 if (!ProcessedCUs.count(CU.get())) 1743 continue; 1744 1745 const DWARFDebugLine::LineTable *LineTable = 1746 DwCtx->getLineTableForUnit(CU.get()); 1747 const std::vector<DWARFDebugLine::FileNameEntry> &FileNames = 1748 LineTable->Prologue.FileNames; 1749 1750 uint16_t DwarfVersion = LineTable->Prologue.getVersion(); 1751 if (DwarfVersion >= 5) { 1752 std::optional<MD5::MD5Result> Checksum; 1753 if (LineTable->Prologue.ContentTypes.HasMD5) 1754 Checksum = LineTable->Prologue.FileNames[0].Checksum; 1755 std::optional<const char *> Name = 1756 dwarf::toString(CU->getUnitDIE().find(dwarf::DW_AT_name), nullptr); 1757 if (std::optional<uint64_t> DWOID = CU->getDWOId()) { 1758 auto Iter = DWOCUs.find(*DWOID); 1759 assert(Iter != DWOCUs.end() && "DWO CU was not found."); 1760 Name = dwarf::toString( 1761 Iter->second->getUnitDIE().find(dwarf::DW_AT_name), nullptr); 1762 } 1763 BinaryLineTable.setRootFile(CU->getCompilationDir(), *Name, Checksum, 1764 std::nullopt); 1765 } 1766 1767 BinaryLineTable.setDwarfVersion(DwarfVersion); 1768 1769 // Assign a unique label to every line table, one per CU. 1770 // Make sure empty debug line tables are registered too. 1771 if (FileNames.empty()) { 1772 cantFail(getDwarfFile("", "<unknown>", 0, std::nullopt, std::nullopt, 1773 CUID, DwarfVersion)); 1774 continue; 1775 } 1776 const uint32_t Offset = DwarfVersion < 5 ? 1 : 0; 1777 for (size_t I = 0, Size = FileNames.size(); I != Size; ++I) { 1778 // Dir indexes start at 1, as DWARF file numbers, and a dir index 0 1779 // means empty dir. 1780 StringRef Dir = ""; 1781 if (FileNames[I].DirIdx != 0 || DwarfVersion >= 5) 1782 if (std::optional<const char *> DirName = dwarf::toString( 1783 LineTable->Prologue 1784 .IncludeDirectories[FileNames[I].DirIdx - Offset])) 1785 Dir = *DirName; 1786 StringRef FileName = ""; 1787 if (std::optional<const char *> FName = 1788 dwarf::toString(FileNames[I].Name)) 1789 FileName = *FName; 1790 assert(FileName != ""); 1791 std::optional<MD5::MD5Result> Checksum; 1792 if (DwarfVersion >= 5 && LineTable->Prologue.ContentTypes.HasMD5) 1793 Checksum = LineTable->Prologue.FileNames[I].Checksum; 1794 cantFail(getDwarfFile(Dir, FileName, 0, Checksum, std::nullopt, CUID, 1795 DwarfVersion)); 1796 } 1797 } 1798 } 1799 1800 bool BinaryContext::shouldEmit(const BinaryFunction &Function) const { 1801 if (Function.isPseudo()) 1802 return false; 1803 1804 if (opts::processAllFunctions()) 1805 return true; 1806 1807 if (Function.isIgnored()) 1808 return false; 1809 1810 // In relocation mode we will emit non-simple functions with CFG. 1811 // If the function does not have a CFG it should be marked as ignored. 1812 return HasRelocations || Function.isSimple(); 1813 } 1814 1815 void BinaryContext::dump(const MCInst &Inst) const { 1816 if (LLVM_UNLIKELY(!InstPrinter)) { 1817 dbgs() << "Cannot dump for InstPrinter is not initialized.\n"; 1818 return; 1819 } 1820 InstPrinter->printInst(&Inst, 0, "", *STI, dbgs()); 1821 dbgs() << "\n"; 1822 } 1823 1824 void BinaryContext::printCFI(raw_ostream &OS, const MCCFIInstruction &Inst) { 1825 uint32_t Operation = Inst.getOperation(); 1826 switch (Operation) { 1827 case MCCFIInstruction::OpSameValue: 1828 OS << "OpSameValue Reg" << Inst.getRegister(); 1829 break; 1830 case MCCFIInstruction::OpRememberState: 1831 OS << "OpRememberState"; 1832 break; 1833 case MCCFIInstruction::OpRestoreState: 1834 OS << "OpRestoreState"; 1835 break; 1836 case MCCFIInstruction::OpOffset: 1837 OS << "OpOffset Reg" << Inst.getRegister() << " " << Inst.getOffset(); 1838 break; 1839 case MCCFIInstruction::OpDefCfaRegister: 1840 OS << "OpDefCfaRegister Reg" << Inst.getRegister(); 1841 break; 1842 case MCCFIInstruction::OpDefCfaOffset: 1843 OS << "OpDefCfaOffset " << Inst.getOffset(); 1844 break; 1845 case MCCFIInstruction::OpDefCfa: 1846 OS << "OpDefCfa Reg" << Inst.getRegister() << " " << Inst.getOffset(); 1847 break; 1848 case MCCFIInstruction::OpRelOffset: 1849 OS << "OpRelOffset Reg" << Inst.getRegister() << " " << Inst.getOffset(); 1850 break; 1851 case MCCFIInstruction::OpAdjustCfaOffset: 1852 OS << "OfAdjustCfaOffset " << Inst.getOffset(); 1853 break; 1854 case MCCFIInstruction::OpEscape: 1855 OS << "OpEscape"; 1856 break; 1857 case MCCFIInstruction::OpRestore: 1858 OS << "OpRestore Reg" << Inst.getRegister(); 1859 break; 1860 case MCCFIInstruction::OpUndefined: 1861 OS << "OpUndefined Reg" << Inst.getRegister(); 1862 break; 1863 case MCCFIInstruction::OpRegister: 1864 OS << "OpRegister Reg" << Inst.getRegister() << " Reg" 1865 << Inst.getRegister2(); 1866 break; 1867 case MCCFIInstruction::OpWindowSave: 1868 OS << "OpWindowSave"; 1869 break; 1870 case MCCFIInstruction::OpGnuArgsSize: 1871 OS << "OpGnuArgsSize"; 1872 break; 1873 default: 1874 OS << "Op#" << Operation; 1875 break; 1876 } 1877 } 1878 1879 MarkerSymType BinaryContext::getMarkerType(const SymbolRef &Symbol) const { 1880 // For aarch64 and riscv, the ABI defines mapping symbols so we identify data 1881 // in the code section (see IHI0056B). $x identifies a symbol starting code or 1882 // the end of a data chunk inside code, $d identifies start of data. 1883 if ((!isAArch64() && !isRISCV()) || ELFSymbolRef(Symbol).getSize()) 1884 return MarkerSymType::NONE; 1885 1886 Expected<StringRef> NameOrError = Symbol.getName(); 1887 Expected<object::SymbolRef::Type> TypeOrError = Symbol.getType(); 1888 1889 if (!TypeOrError || !NameOrError) 1890 return MarkerSymType::NONE; 1891 1892 if (*TypeOrError != SymbolRef::ST_Unknown) 1893 return MarkerSymType::NONE; 1894 1895 if (*NameOrError == "$x" || NameOrError->starts_with("$x.")) 1896 return MarkerSymType::CODE; 1897 1898 // $x<ISA> 1899 if (isRISCV() && NameOrError->starts_with("$x")) 1900 return MarkerSymType::CODE; 1901 1902 if (*NameOrError == "$d" || NameOrError->starts_with("$d.")) 1903 return MarkerSymType::DATA; 1904 1905 return MarkerSymType::NONE; 1906 } 1907 1908 bool BinaryContext::isMarker(const SymbolRef &Symbol) const { 1909 return getMarkerType(Symbol) != MarkerSymType::NONE; 1910 } 1911 1912 static void printDebugInfo(raw_ostream &OS, const MCInst &Instruction, 1913 const BinaryFunction *Function, 1914 DWARFContext *DwCtx) { 1915 DebugLineTableRowRef RowRef = 1916 DebugLineTableRowRef::fromSMLoc(Instruction.getLoc()); 1917 if (RowRef == DebugLineTableRowRef::NULL_ROW) 1918 return; 1919 1920 const DWARFDebugLine::LineTable *LineTable; 1921 if (Function && Function->getDWARFUnit() && 1922 Function->getDWARFUnit()->getOffset() == RowRef.DwCompileUnitIndex) { 1923 LineTable = Function->getDWARFLineTable(); 1924 } else { 1925 LineTable = DwCtx->getLineTableForUnit( 1926 DwCtx->getCompileUnitForOffset(RowRef.DwCompileUnitIndex)); 1927 } 1928 assert(LineTable && "line table expected for instruction with debug info"); 1929 1930 const DWARFDebugLine::Row &Row = LineTable->Rows[RowRef.RowIndex - 1]; 1931 StringRef FileName = ""; 1932 if (std::optional<const char *> FName = 1933 dwarf::toString(LineTable->Prologue.FileNames[Row.File - 1].Name)) 1934 FileName = *FName; 1935 OS << " # debug line " << FileName << ":" << Row.Line; 1936 if (Row.Column) 1937 OS << ":" << Row.Column; 1938 if (Row.Discriminator) 1939 OS << " discriminator:" << Row.Discriminator; 1940 } 1941 1942 void BinaryContext::printInstruction(raw_ostream &OS, const MCInst &Instruction, 1943 uint64_t Offset, 1944 const BinaryFunction *Function, 1945 bool PrintMCInst, bool PrintMemData, 1946 bool PrintRelocations, 1947 StringRef Endl) const { 1948 OS << format(" %08" PRIx64 ": ", Offset); 1949 if (MIB->isCFI(Instruction)) { 1950 uint32_t Offset = Instruction.getOperand(0).getImm(); 1951 OS << "\t!CFI\t$" << Offset << "\t; "; 1952 if (Function) 1953 printCFI(OS, *Function->getCFIFor(Instruction)); 1954 OS << Endl; 1955 return; 1956 } 1957 if (std::optional<uint32_t> DynamicID = 1958 MIB->getDynamicBranchID(Instruction)) { 1959 OS << "\tjit\t" << MIB->getTargetSymbol(Instruction)->getName() 1960 << " # ID: " << DynamicID; 1961 } else { 1962 InstPrinter->printInst(&Instruction, 0, "", *STI, OS); 1963 } 1964 if (MIB->isCall(Instruction)) { 1965 if (MIB->isTailCall(Instruction)) 1966 OS << " # TAILCALL "; 1967 if (MIB->isInvoke(Instruction)) { 1968 const std::optional<MCPlus::MCLandingPad> EHInfo = 1969 MIB->getEHInfo(Instruction); 1970 OS << " # handler: "; 1971 if (EHInfo->first) 1972 OS << *EHInfo->first; 1973 else 1974 OS << '0'; 1975 OS << "; action: " << EHInfo->second; 1976 const int64_t GnuArgsSize = MIB->getGnuArgsSize(Instruction); 1977 if (GnuArgsSize >= 0) 1978 OS << "; GNU_args_size = " << GnuArgsSize; 1979 } 1980 } else if (MIB->isIndirectBranch(Instruction)) { 1981 if (uint64_t JTAddress = MIB->getJumpTable(Instruction)) { 1982 OS << " # JUMPTABLE @0x" << Twine::utohexstr(JTAddress); 1983 } else { 1984 OS << " # UNKNOWN CONTROL FLOW"; 1985 } 1986 } 1987 if (std::optional<uint32_t> Offset = MIB->getOffset(Instruction)) 1988 OS << " # Offset: " << *Offset; 1989 if (std::optional<uint32_t> Size = MIB->getSize(Instruction)) 1990 OS << " # Size: " << *Size; 1991 if (MCSymbol *Label = MIB->getInstLabel(Instruction)) 1992 OS << " # Label: " << *Label; 1993 1994 MIB->printAnnotations(Instruction, OS); 1995 1996 if (opts::PrintDebugInfo) 1997 printDebugInfo(OS, Instruction, Function, DwCtx.get()); 1998 1999 if ((opts::PrintRelocations || PrintRelocations) && Function) { 2000 const uint64_t Size = computeCodeSize(&Instruction, &Instruction + 1); 2001 Function->printRelocations(OS, Offset, Size); 2002 } 2003 2004 OS << Endl; 2005 2006 if (PrintMCInst) { 2007 Instruction.dump_pretty(OS, InstPrinter.get()); 2008 OS << Endl; 2009 } 2010 } 2011 2012 std::optional<uint64_t> 2013 BinaryContext::getBaseAddressForMapping(uint64_t MMapAddress, 2014 uint64_t FileOffset) const { 2015 // Find a segment with a matching file offset. 2016 for (auto &KV : SegmentMapInfo) { 2017 const SegmentInfo &SegInfo = KV.second; 2018 // FileOffset is got from perf event, 2019 // and it is equal to alignDown(SegInfo.FileOffset, pagesize). 2020 // If the pagesize is not equal to SegInfo.Alignment. 2021 // FileOffset and SegInfo.FileOffset should be aligned first, 2022 // and then judge whether they are equal. 2023 if (alignDown(SegInfo.FileOffset, SegInfo.Alignment) == 2024 alignDown(FileOffset, SegInfo.Alignment)) { 2025 // The function's offset from base address in VAS is aligned by pagesize 2026 // instead of SegInfo.Alignment. Pagesize can't be got from perf events. 2027 // However, The ELF document says that SegInfo.FileOffset should equal 2028 // to SegInfo.Address, modulo the pagesize. 2029 // Reference: https://refspecs.linuxfoundation.org/elf/elf.pdf 2030 2031 // So alignDown(SegInfo.Address, pagesize) can be calculated by: 2032 // alignDown(SegInfo.Address, pagesize) 2033 // = SegInfo.Address - (SegInfo.Address % pagesize) 2034 // = SegInfo.Address - (SegInfo.FileOffset % pagesize) 2035 // = SegInfo.Address - SegInfo.FileOffset + 2036 // alignDown(SegInfo.FileOffset, pagesize) 2037 // = SegInfo.Address - SegInfo.FileOffset + FileOffset 2038 return MMapAddress - (SegInfo.Address - SegInfo.FileOffset + FileOffset); 2039 } 2040 } 2041 2042 return std::nullopt; 2043 } 2044 2045 ErrorOr<BinarySection &> BinaryContext::getSectionForAddress(uint64_t Address) { 2046 auto SI = AddressToSection.upper_bound(Address); 2047 if (SI != AddressToSection.begin()) { 2048 --SI; 2049 uint64_t UpperBound = SI->first + SI->second->getSize(); 2050 if (!SI->second->getSize()) 2051 UpperBound += 1; 2052 if (UpperBound > Address) 2053 return *SI->second; 2054 } 2055 return std::make_error_code(std::errc::bad_address); 2056 } 2057 2058 ErrorOr<StringRef> 2059 BinaryContext::getSectionNameForAddress(uint64_t Address) const { 2060 if (ErrorOr<const BinarySection &> Section = getSectionForAddress(Address)) 2061 return Section->getName(); 2062 return std::make_error_code(std::errc::bad_address); 2063 } 2064 2065 BinarySection &BinaryContext::registerSection(BinarySection *Section) { 2066 auto Res = Sections.insert(Section); 2067 (void)Res; 2068 assert(Res.second && "can't register the same section twice."); 2069 2070 // Only register allocatable sections in the AddressToSection map. 2071 if (Section->isAllocatable() && Section->getAddress()) 2072 AddressToSection.insert(std::make_pair(Section->getAddress(), Section)); 2073 NameToSection.insert( 2074 std::make_pair(std::string(Section->getName()), Section)); 2075 if (Section->hasSectionRef()) 2076 SectionRefToBinarySection.insert( 2077 std::make_pair(Section->getSectionRef(), Section)); 2078 2079 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: registering " << *Section << "\n"); 2080 return *Section; 2081 } 2082 2083 BinarySection &BinaryContext::registerSection(SectionRef Section) { 2084 return registerSection(new BinarySection(*this, Section)); 2085 } 2086 2087 BinarySection & 2088 BinaryContext::registerSection(const Twine &SectionName, 2089 const BinarySection &OriginalSection) { 2090 return registerSection( 2091 new BinarySection(*this, SectionName, OriginalSection)); 2092 } 2093 2094 BinarySection & 2095 BinaryContext::registerOrUpdateSection(const Twine &Name, unsigned ELFType, 2096 unsigned ELFFlags, uint8_t *Data, 2097 uint64_t Size, unsigned Alignment) { 2098 auto NamedSections = getSectionByName(Name); 2099 if (NamedSections.begin() != NamedSections.end()) { 2100 assert(std::next(NamedSections.begin()) == NamedSections.end() && 2101 "can only update unique sections"); 2102 BinarySection *Section = NamedSections.begin()->second; 2103 2104 LLVM_DEBUG(dbgs() << "BOLT-DEBUG: updating " << *Section << " -> "); 2105 const bool Flag = Section->isAllocatable(); 2106 (void)Flag; 2107 Section->update(Data, Size, Alignment, ELFType, ELFFlags); 2108 LLVM_DEBUG(dbgs() << *Section << "\n"); 2109 // FIXME: Fix section flags/attributes for MachO. 2110 if (isELF()) 2111 assert(Flag == Section->isAllocatable() && 2112 "can't change section allocation status"); 2113 return *Section; 2114 } 2115 2116 return registerSection( 2117 new BinarySection(*this, Name, Data, Size, Alignment, ELFType, ELFFlags)); 2118 } 2119 2120 void BinaryContext::deregisterSectionName(const BinarySection &Section) { 2121 auto NameRange = NameToSection.equal_range(Section.getName().str()); 2122 while (NameRange.first != NameRange.second) { 2123 if (NameRange.first->second == &Section) { 2124 NameToSection.erase(NameRange.first); 2125 break; 2126 } 2127 ++NameRange.first; 2128 } 2129 } 2130 2131 void BinaryContext::deregisterUnusedSections() { 2132 ErrorOr<BinarySection &> AbsSection = getUniqueSectionByName("<absolute>"); 2133 for (auto SI = Sections.begin(); SI != Sections.end();) { 2134 BinarySection *Section = *SI; 2135 // We check getOutputData() instead of getOutputSize() because sometimes 2136 // zero-sized .text.cold sections are allocated. 2137 if (Section->hasSectionRef() || Section->getOutputData() || 2138 (AbsSection && Section == &AbsSection.get())) { 2139 ++SI; 2140 continue; 2141 } 2142 2143 LLVM_DEBUG(dbgs() << "LLVM-DEBUG: deregistering " << Section->getName() 2144 << '\n';); 2145 deregisterSectionName(*Section); 2146 SI = Sections.erase(SI); 2147 delete Section; 2148 } 2149 } 2150 2151 bool BinaryContext::deregisterSection(BinarySection &Section) { 2152 BinarySection *SectionPtr = &Section; 2153 auto Itr = Sections.find(SectionPtr); 2154 if (Itr != Sections.end()) { 2155 auto Range = AddressToSection.equal_range(SectionPtr->getAddress()); 2156 while (Range.first != Range.second) { 2157 if (Range.first->second == SectionPtr) { 2158 AddressToSection.erase(Range.first); 2159 break; 2160 } 2161 ++Range.first; 2162 } 2163 2164 deregisterSectionName(*SectionPtr); 2165 Sections.erase(Itr); 2166 delete SectionPtr; 2167 return true; 2168 } 2169 return false; 2170 } 2171 2172 void BinaryContext::renameSection(BinarySection &Section, 2173 const Twine &NewName) { 2174 auto Itr = Sections.find(&Section); 2175 assert(Itr != Sections.end() && "Section must exist to be renamed."); 2176 Sections.erase(Itr); 2177 2178 deregisterSectionName(Section); 2179 2180 Section.Name = NewName.str(); 2181 Section.setOutputName(Section.Name); 2182 2183 NameToSection.insert(std::make_pair(Section.Name, &Section)); 2184 2185 // Reinsert with the new name. 2186 Sections.insert(&Section); 2187 } 2188 2189 void BinaryContext::printSections(raw_ostream &OS) const { 2190 for (BinarySection *const &Section : Sections) 2191 OS << "BOLT-INFO: " << *Section << "\n"; 2192 } 2193 2194 BinarySection &BinaryContext::absoluteSection() { 2195 if (ErrorOr<BinarySection &> Section = getUniqueSectionByName("<absolute>")) 2196 return *Section; 2197 return registerOrUpdateSection("<absolute>", ELF::SHT_NULL, 0u); 2198 } 2199 2200 ErrorOr<uint64_t> BinaryContext::getUnsignedValueAtAddress(uint64_t Address, 2201 size_t Size) const { 2202 const ErrorOr<const BinarySection &> Section = getSectionForAddress(Address); 2203 if (!Section) 2204 return std::make_error_code(std::errc::bad_address); 2205 2206 if (Section->isVirtual()) 2207 return 0; 2208 2209 DataExtractor DE(Section->getContents(), AsmInfo->isLittleEndian(), 2210 AsmInfo->getCodePointerSize()); 2211 auto ValueOffset = static_cast<uint64_t>(Address - Section->getAddress()); 2212 return DE.getUnsigned(&ValueOffset, Size); 2213 } 2214 2215 ErrorOr<uint64_t> BinaryContext::getSignedValueAtAddress(uint64_t Address, 2216 size_t Size) const { 2217 const ErrorOr<const BinarySection &> Section = getSectionForAddress(Address); 2218 if (!Section) 2219 return std::make_error_code(std::errc::bad_address); 2220 2221 if (Section->isVirtual()) 2222 return 0; 2223 2224 DataExtractor DE(Section->getContents(), AsmInfo->isLittleEndian(), 2225 AsmInfo->getCodePointerSize()); 2226 auto ValueOffset = static_cast<uint64_t>(Address - Section->getAddress()); 2227 return DE.getSigned(&ValueOffset, Size); 2228 } 2229 2230 void BinaryContext::addRelocation(uint64_t Address, MCSymbol *Symbol, 2231 uint64_t Type, uint64_t Addend, 2232 uint64_t Value) { 2233 ErrorOr<BinarySection &> Section = getSectionForAddress(Address); 2234 assert(Section && "cannot find section for address"); 2235 Section->addRelocation(Address - Section->getAddress(), Symbol, Type, Addend, 2236 Value); 2237 } 2238 2239 void BinaryContext::addDynamicRelocation(uint64_t Address, MCSymbol *Symbol, 2240 uint64_t Type, uint64_t Addend, 2241 uint64_t Value) { 2242 ErrorOr<BinarySection &> Section = getSectionForAddress(Address); 2243 assert(Section && "cannot find section for address"); 2244 Section->addDynamicRelocation(Address - Section->getAddress(), Symbol, Type, 2245 Addend, Value); 2246 } 2247 2248 bool BinaryContext::removeRelocationAt(uint64_t Address) { 2249 ErrorOr<BinarySection &> Section = getSectionForAddress(Address); 2250 assert(Section && "cannot find section for address"); 2251 return Section->removeRelocationAt(Address - Section->getAddress()); 2252 } 2253 2254 const Relocation *BinaryContext::getRelocationAt(uint64_t Address) const { 2255 ErrorOr<const BinarySection &> Section = getSectionForAddress(Address); 2256 if (!Section) 2257 return nullptr; 2258 2259 return Section->getRelocationAt(Address - Section->getAddress()); 2260 } 2261 2262 const Relocation * 2263 BinaryContext::getDynamicRelocationAt(uint64_t Address) const { 2264 ErrorOr<const BinarySection &> Section = getSectionForAddress(Address); 2265 if (!Section) 2266 return nullptr; 2267 2268 return Section->getDynamicRelocationAt(Address - Section->getAddress()); 2269 } 2270 2271 void BinaryContext::markAmbiguousRelocations(BinaryData &BD, 2272 const uint64_t Address) { 2273 auto setImmovable = [&](BinaryData &BD) { 2274 BinaryData *Root = BD.getAtomicRoot(); 2275 LLVM_DEBUG(if (Root->isMoveable()) { 2276 dbgs() << "BOLT-DEBUG: setting " << *Root << " as immovable " 2277 << "due to ambiguous relocation referencing 0x" 2278 << Twine::utohexstr(Address) << '\n'; 2279 }); 2280 Root->setIsMoveable(false); 2281 }; 2282 2283 if (Address == BD.getAddress()) { 2284 setImmovable(BD); 2285 2286 // Set previous symbol as immovable 2287 BinaryData *Prev = getBinaryDataContainingAddress(Address - 1); 2288 if (Prev && Prev->getEndAddress() == BD.getAddress()) 2289 setImmovable(*Prev); 2290 } 2291 2292 if (Address == BD.getEndAddress()) { 2293 setImmovable(BD); 2294 2295 // Set next symbol as immovable 2296 BinaryData *Next = getBinaryDataContainingAddress(BD.getEndAddress()); 2297 if (Next && Next->getAddress() == BD.getEndAddress()) 2298 setImmovable(*Next); 2299 } 2300 } 2301 2302 BinaryFunction *BinaryContext::getFunctionForSymbol(const MCSymbol *Symbol, 2303 uint64_t *EntryDesc) { 2304 std::shared_lock<llvm::sys::RWMutex> Lock(SymbolToFunctionMapMutex); 2305 auto BFI = SymbolToFunctionMap.find(Symbol); 2306 if (BFI == SymbolToFunctionMap.end()) 2307 return nullptr; 2308 2309 BinaryFunction *BF = BFI->second; 2310 if (EntryDesc) 2311 *EntryDesc = BF->getEntryIDForSymbol(Symbol); 2312 2313 return BF; 2314 } 2315 2316 std::string 2317 BinaryContext::generateBugReportMessage(StringRef Message, 2318 const BinaryFunction &Function) const { 2319 std::string Msg; 2320 raw_string_ostream SS(Msg); 2321 SS << "=======================================\n"; 2322 SS << "BOLT is unable to proceed because it couldn't properly understand " 2323 "this function.\n"; 2324 SS << "If you are running the most recent version of BOLT, you may " 2325 "want to " 2326 "report this and paste this dump.\nPlease check that there is no " 2327 "sensitive contents being shared in this dump.\n"; 2328 SS << "\nOffending function: " << Function.getPrintName() << "\n\n"; 2329 ScopedPrinter SP(SS); 2330 SP.printBinaryBlock("Function contents", *Function.getData()); 2331 SS << "\n"; 2332 const_cast<BinaryFunction &>(Function).print(SS, ""); 2333 SS << "ERROR: " << Message; 2334 SS << "\n=======================================\n"; 2335 return Msg; 2336 } 2337 2338 BinaryFunction * 2339 BinaryContext::createInjectedBinaryFunction(const std::string &Name, 2340 bool IsSimple) { 2341 InjectedBinaryFunctions.push_back(new BinaryFunction(Name, *this, IsSimple)); 2342 BinaryFunction *BF = InjectedBinaryFunctions.back(); 2343 setSymbolToFunctionMap(BF->getSymbol(), BF); 2344 BF->CurrentState = BinaryFunction::State::CFG; 2345 return BF; 2346 } 2347 2348 std::pair<size_t, size_t> 2349 BinaryContext::calculateEmittedSize(BinaryFunction &BF, bool FixBranches) { 2350 // Adjust branch instruction to match the current layout. 2351 if (FixBranches) 2352 BF.fixBranches(); 2353 2354 // Create local MC context to isolate the effect of ephemeral code emission. 2355 IndependentCodeEmitter MCEInstance = createIndependentMCCodeEmitter(); 2356 MCContext *LocalCtx = MCEInstance.LocalCtx.get(); 2357 MCAsmBackend *MAB = 2358 TheTarget->createMCAsmBackend(*STI, *MRI, MCTargetOptions()); 2359 2360 SmallString<256> Code; 2361 raw_svector_ostream VecOS(Code); 2362 2363 std::unique_ptr<MCObjectWriter> OW = MAB->createObjectWriter(VecOS); 2364 std::unique_ptr<MCStreamer> Streamer(TheTarget->createMCObjectStreamer( 2365 *TheTriple, *LocalCtx, std::unique_ptr<MCAsmBackend>(MAB), std::move(OW), 2366 std::unique_ptr<MCCodeEmitter>(MCEInstance.MCE.release()), *STI, 2367 /*RelaxAll=*/false, 2368 /*IncrementalLinkerCompatible=*/false, 2369 /*DWARFMustBeAtTheEnd=*/false)); 2370 2371 Streamer->initSections(false, *STI); 2372 2373 MCSection *Section = MCEInstance.LocalMOFI->getTextSection(); 2374 Section->setHasInstructions(true); 2375 2376 // Create symbols in the LocalCtx so that they get destroyed with it. 2377 MCSymbol *StartLabel = LocalCtx->createTempSymbol(); 2378 MCSymbol *EndLabel = LocalCtx->createTempSymbol(); 2379 2380 Streamer->switchSection(Section); 2381 Streamer->emitLabel(StartLabel); 2382 emitFunctionBody(*Streamer, BF, BF.getLayout().getMainFragment(), 2383 /*EmitCodeOnly=*/true); 2384 Streamer->emitLabel(EndLabel); 2385 2386 using LabelRange = std::pair<const MCSymbol *, const MCSymbol *>; 2387 SmallVector<LabelRange> SplitLabels; 2388 for (FunctionFragment &FF : BF.getLayout().getSplitFragments()) { 2389 MCSymbol *const SplitStartLabel = LocalCtx->createTempSymbol(); 2390 MCSymbol *const SplitEndLabel = LocalCtx->createTempSymbol(); 2391 SplitLabels.emplace_back(SplitStartLabel, SplitEndLabel); 2392 2393 MCSectionELF *const SplitSection = LocalCtx->getELFSection( 2394 BF.getCodeSectionName(FF.getFragmentNum()), ELF::SHT_PROGBITS, 2395 ELF::SHF_EXECINSTR | ELF::SHF_ALLOC); 2396 SplitSection->setHasInstructions(true); 2397 Streamer->switchSection(SplitSection); 2398 2399 Streamer->emitLabel(SplitStartLabel); 2400 emitFunctionBody(*Streamer, BF, FF, /*EmitCodeOnly=*/true); 2401 Streamer->emitLabel(SplitEndLabel); 2402 // To avoid calling MCObjectStreamer::flushPendingLabels() which is 2403 // private 2404 Streamer->emitBytes(StringRef("")); 2405 Streamer->switchSection(Section); 2406 } 2407 2408 // To avoid calling MCObjectStreamer::flushPendingLabels() which is private or 2409 // MCStreamer::Finish(), which does more than we want 2410 Streamer->emitBytes(StringRef("")); 2411 2412 MCAssembler &Assembler = 2413 static_cast<MCObjectStreamer *>(Streamer.get())->getAssembler(); 2414 MCAsmLayout Layout(Assembler); 2415 Assembler.layout(Layout); 2416 2417 // Obtain fragment sizes. 2418 std::vector<uint64_t> FragmentSizes; 2419 // Main fragment size. 2420 const uint64_t HotSize = 2421 Layout.getSymbolOffset(*EndLabel) - Layout.getSymbolOffset(*StartLabel); 2422 FragmentSizes.push_back(HotSize); 2423 // Split fragment sizes. 2424 uint64_t ColdSize = 0; 2425 for (const auto &Labels : SplitLabels) { 2426 uint64_t Size = Layout.getSymbolOffset(*Labels.second) - 2427 Layout.getSymbolOffset(*Labels.first); 2428 FragmentSizes.push_back(Size); 2429 ColdSize += Size; 2430 } 2431 2432 // Populate new start and end offsets of each basic block. 2433 uint64_t FragmentIndex = 0; 2434 for (FunctionFragment &FF : BF.getLayout().fragments()) { 2435 BinaryBasicBlock *PrevBB = nullptr; 2436 for (BinaryBasicBlock *BB : FF) { 2437 const uint64_t BBStartOffset = Layout.getSymbolOffset(*(BB->getLabel())); 2438 BB->setOutputStartAddress(BBStartOffset); 2439 if (PrevBB) 2440 PrevBB->setOutputEndAddress(BBStartOffset); 2441 PrevBB = BB; 2442 } 2443 if (PrevBB) 2444 PrevBB->setOutputEndAddress(FragmentSizes[FragmentIndex]); 2445 FragmentIndex++; 2446 } 2447 2448 // Clean-up the effect of the code emission. 2449 for (const MCSymbol &Symbol : Assembler.symbols()) { 2450 MCSymbol *MutableSymbol = const_cast<MCSymbol *>(&Symbol); 2451 MutableSymbol->setUndefined(); 2452 MutableSymbol->setIsRegistered(false); 2453 } 2454 2455 return std::make_pair(HotSize, ColdSize); 2456 } 2457 2458 bool BinaryContext::validateInstructionEncoding( 2459 ArrayRef<uint8_t> InputSequence) const { 2460 MCInst Inst; 2461 uint64_t InstSize; 2462 DisAsm->getInstruction(Inst, InstSize, InputSequence, 0, nulls()); 2463 assert(InstSize == InputSequence.size() && 2464 "Disassembled instruction size does not match the sequence."); 2465 2466 SmallString<256> Code; 2467 SmallVector<MCFixup, 4> Fixups; 2468 2469 MCE->encodeInstruction(Inst, Code, Fixups, *STI); 2470 auto OutputSequence = ArrayRef<uint8_t>((uint8_t *)Code.data(), Code.size()); 2471 if (InputSequence != OutputSequence) { 2472 if (opts::Verbosity > 1) { 2473 this->errs() << "BOLT-WARNING: mismatched encoding detected\n" 2474 << " input: " << InputSequence << '\n' 2475 << " output: " << OutputSequence << '\n'; 2476 } 2477 return false; 2478 } 2479 2480 return true; 2481 } 2482 2483 uint64_t BinaryContext::getHotThreshold() const { 2484 static uint64_t Threshold = 0; 2485 if (Threshold == 0) { 2486 Threshold = std::max( 2487 (uint64_t)opts::ExecutionCountThreshold, 2488 NumProfiledFuncs ? SumExecutionCount / (2 * NumProfiledFuncs) : 1); 2489 } 2490 return Threshold; 2491 } 2492 2493 BinaryFunction *BinaryContext::getBinaryFunctionContainingAddress( 2494 uint64_t Address, bool CheckPastEnd, bool UseMaxSize) { 2495 auto FI = BinaryFunctions.upper_bound(Address); 2496 if (FI == BinaryFunctions.begin()) 2497 return nullptr; 2498 --FI; 2499 2500 const uint64_t UsedSize = 2501 UseMaxSize ? FI->second.getMaxSize() : FI->second.getSize(); 2502 2503 if (Address >= FI->first + UsedSize + (CheckPastEnd ? 1 : 0)) 2504 return nullptr; 2505 2506 return &FI->second; 2507 } 2508 2509 BinaryFunction *BinaryContext::getBinaryFunctionAtAddress(uint64_t Address) { 2510 // First, try to find a function starting at the given address. If the 2511 // function was folded, this will get us the original folded function if it 2512 // wasn't removed from the list, e.g. in non-relocation mode. 2513 auto BFI = BinaryFunctions.find(Address); 2514 if (BFI != BinaryFunctions.end()) 2515 return &BFI->second; 2516 2517 // We might have folded the function matching the object at the given 2518 // address. In such case, we look for a function matching the symbol 2519 // registered at the original address. The new function (the one that the 2520 // original was folded into) will hold the symbol. 2521 if (const BinaryData *BD = getBinaryDataAtAddress(Address)) { 2522 uint64_t EntryID = 0; 2523 BinaryFunction *BF = getFunctionForSymbol(BD->getSymbol(), &EntryID); 2524 if (BF && EntryID == 0) 2525 return BF; 2526 } 2527 return nullptr; 2528 } 2529 2530 DebugAddressRangesVector BinaryContext::translateModuleAddressRanges( 2531 const DWARFAddressRangesVector &InputRanges) const { 2532 DebugAddressRangesVector OutputRanges; 2533 2534 for (const DWARFAddressRange Range : InputRanges) { 2535 auto BFI = BinaryFunctions.lower_bound(Range.LowPC); 2536 while (BFI != BinaryFunctions.end()) { 2537 const BinaryFunction &Function = BFI->second; 2538 if (Function.getAddress() >= Range.HighPC) 2539 break; 2540 const DebugAddressRangesVector FunctionRanges = 2541 Function.getOutputAddressRanges(); 2542 llvm::move(FunctionRanges, std::back_inserter(OutputRanges)); 2543 std::advance(BFI, 1); 2544 } 2545 } 2546 2547 return OutputRanges; 2548 } 2549 2550 } // namespace bolt 2551 } // namespace llvm 2552