tools/llvm-cfi-verify/lib/FileAnalysis.cpp

   1 //===- FileAnalysis.cpp -----------------------------------------*- C++ -*-===//
   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 #include "FileAnalysis.h"
  10 #include "GraphBuilder.h"
  11
  12 #include "llvm/BinaryFormat/ELF.h"
  13 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
  14 #include "llvm/MC/MCAsmInfo.h"
  15 #include "llvm/MC/MCContext.h"
  16 #include "llvm/MC/MCDisassembler/MCDisassembler.h"
  17 #include "llvm/MC/MCInst.h"
  18 #include "llvm/MC/MCInstPrinter.h"
  19 #include "llvm/MC/MCInstrAnalysis.h"
  20 #include "llvm/MC/MCInstrDesc.h"
  21 #include "llvm/MC/MCInstrInfo.h"
  22 #include "llvm/MC/MCObjectFileInfo.h"
  23 #include "llvm/MC/MCRegisterInfo.h"
  24 #include "llvm/MC/MCSubtargetInfo.h"
  25 #include "llvm/Object/Binary.h"
  26 #include "llvm/Object/COFF.h"
  27 #include "llvm/Object/ELFObjectFile.h"
  28 #include "llvm/Object/ObjectFile.h"
  29 #include "llvm/Support/Casting.h"
  30 #include "llvm/Support/CommandLine.h"
  31 #include "llvm/Support/Error.h"
  32 #include "llvm/Support/MemoryBuffer.h"
  33 #include "llvm/Support/TargetRegistry.h"
  34 #include "llvm/Support/TargetSelect.h"
  35 #include "llvm/Support/raw_ostream.h"
  36
  37
  38 using Instr = llvm::cfi_verify::FileAnalysis::Instr;
  39 using LLVMSymbolizer = llvm::symbolize::LLVMSymbolizer;
  40
  41 namespace llvm {
  42 namespace cfi_verify {
  43
  44 bool IgnoreDWARFFlag;
  45
  46 static cl::opt<bool, true> IgnoreDWARFArg(
  47     "ignore-dwarf",
  48     cl::desc(
  49         "Ignore all DWARF data. This relaxes the requirements for all "
  50         "statically linked libraries to have been compiled with '-g', but "
  51         "will result in false positives for 'CFI unprotected' instructions."),
  52     cl::location(IgnoreDWARFFlag), cl::init(false));
  53
  54 StringRef stringCFIProtectionStatus(CFIProtectionStatus Status) {
  55   switch (Status) {
  56   case CFIProtectionStatus::PROTECTED:
  57     return "PROTECTED";
  58   case CFIProtectionStatus::FAIL_NOT_INDIRECT_CF:
  59     return "FAIL_NOT_INDIRECT_CF";
  60   case CFIProtectionStatus::FAIL_ORPHANS:
  61     return "FAIL_ORPHANS";
  62   case CFIProtectionStatus::FAIL_BAD_CONDITIONAL_BRANCH:
  63     return "FAIL_BAD_CONDITIONAL_BRANCH";
  64   case CFIProtectionStatus::FAIL_REGISTER_CLOBBERED:
  65     return "FAIL_REGISTER_CLOBBERED";
  66   case CFIProtectionStatus::FAIL_INVALID_INSTRUCTION:
  67     return "FAIL_INVALID_INSTRUCTION";
  68   }
  69   llvm_unreachable("Attempted to stringify an unknown enum value.");
  70 }
  71
  72 Expected<FileAnalysis> FileAnalysis::Create(StringRef Filename) {
  73   // Open the filename provided.
  74   Expected<object::OwningBinary<object::Binary>> BinaryOrErr =
  75       object::createBinary(Filename);
  76   if (!BinaryOrErr)
  77     return BinaryOrErr.takeError();
  78
  79   // Construct the object and allow it to take ownership of the binary.
  80   object::OwningBinary<object::Binary> Binary = std::move(BinaryOrErr.get());
  81   FileAnalysis Analysis(std::move(Binary));
  82
  83   Analysis.Object = dyn_cast<object::ObjectFile>(Analysis.Binary.getBinary());
  84   if (!Analysis.Object)
  85     return make_error<UnsupportedDisassembly>("Failed to cast object");
  86
  87   switch (Analysis.Object->getArch()) {
  88     case Triple::x86:
  89     case Triple::x86_64:
  90     case Triple::aarch64:
  91     case Triple::aarch64_be:
  92       break;
  93     default:
  94       return make_error<UnsupportedDisassembly>("Unsupported architecture.");
  95   }
  96
  97   Analysis.ObjectTriple = Analysis.Object->makeTriple();
  98   Analysis.Features = Analysis.Object->getFeatures();
  99
 100   // Init the rest of the object.
 101   if (auto InitResponse = Analysis.initialiseDisassemblyMembers())
 102     return std::move(InitResponse);
 103
 104   if (auto SectionParseResponse = Analysis.parseCodeSections())
 105     return std::move(SectionParseResponse);
 106
 107   if (auto SymbolTableParseResponse = Analysis.parseSymbolTable())
 108     return std::move(SymbolTableParseResponse);
 109
 110   return std::move(Analysis);
 111 }
 112
 113 FileAnalysis::FileAnalysis(object::OwningBinary<object::Binary> Binary)
 114     : Binary(std::move(Binary)) {}
 115
 116 FileAnalysis::FileAnalysis(const Triple &ObjectTriple,
 117                            const SubtargetFeatures &Features)
 118     : ObjectTriple(ObjectTriple), Features(Features) {}
 119
 120 const Instr *
 121 FileAnalysis::getPrevInstructionSequential(const Instr &InstrMeta) const {
 122   std::map<uint64_t, Instr>::const_iterator KV =
 123       Instructions.find(InstrMeta.VMAddress);
 124   if (KV == Instructions.end() || KV == Instructions.begin())
 125     return nullptr;
 126
 127   if (!(--KV)->second.Valid)
 128     return nullptr;
 129
 130   return &KV->second;
 131 }
 132
 133 const Instr *
 134 FileAnalysis::getNextInstructionSequential(const Instr &InstrMeta) const {
 135   std::map<uint64_t, Instr>::const_iterator KV =
 136       Instructions.find(InstrMeta.VMAddress);
 137   if (KV == Instructions.end() || ++KV == Instructions.end())
 138     return nullptr;
 139
 140   if (!KV->second.Valid)
 141     return nullptr;
 142
 143   return &KV->second;
 144 }
 145
 146 bool FileAnalysis::usesRegisterOperand(const Instr &InstrMeta) const {
 147   for (const auto &Operand : InstrMeta.Instruction) {
 148     if (Operand.isReg())
 149       return true;
 150   }
 151   return false;
 152 }
 153
 154 const Instr *FileAnalysis::getInstruction(uint64_t Address) const {
 155   const auto &InstrKV = Instructions.find(Address);
 156   if (InstrKV == Instructions.end())
 157     return nullptr;
 158
 159   return &InstrKV->second;
 160 }
 161
 162 const Instr &FileAnalysis::getInstructionOrDie(uint64_t Address) const {
 163   const auto &InstrKV = Instructions.find(Address);
 164   assert(InstrKV != Instructions.end() && "Address doesn't exist.");
 165   return InstrKV->second;
 166 }
 167
 168 bool FileAnalysis::isCFITrap(const Instr &InstrMeta) const {
 169   const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
 170   return InstrDesc.isTrap() || willTrapOnCFIViolation(InstrMeta);
 171 }
 172
 173 bool FileAnalysis::willTrapOnCFIViolation(const Instr &InstrMeta) const {
 174   const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
 175   if (!InstrDesc.isCall())
 176     return false;
 177   uint64_t Target;
 178   if (!MIA->evaluateBranch(InstrMeta.Instruction, InstrMeta.VMAddress,
 179                            InstrMeta.InstructionSize, Target))
 180     return false;
 181   return TrapOnFailFunctionAddresses.count(Target) > 0;
 182 }
 183
 184 bool FileAnalysis::canFallThrough(const Instr &InstrMeta) const {
 185   if (!InstrMeta.Valid)
 186     return false;
 187
 188   if (isCFITrap(InstrMeta))
 189     return false;
 190
 191   const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
 192   if (InstrDesc.mayAffectControlFlow(InstrMeta.Instruction, *RegisterInfo))
 193     return InstrDesc.isConditionalBranch();
 194
 195   return true;
 196 }
 197
 198 const Instr *
 199 FileAnalysis::getDefiniteNextInstruction(const Instr &InstrMeta) const {
 200   if (!InstrMeta.Valid)
 201     return nullptr;
 202
 203   if (isCFITrap(InstrMeta))
 204     return nullptr;
 205
 206   const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
 207   const Instr *NextMetaPtr;
 208   if (InstrDesc.mayAffectControlFlow(InstrMeta.Instruction, *RegisterInfo)) {
 209     if (InstrDesc.isConditionalBranch())
 210       return nullptr;
 211
 212     uint64_t Target;
 213     if (!MIA->evaluateBranch(InstrMeta.Instruction, InstrMeta.VMAddress,
 214                              InstrMeta.InstructionSize, Target))
 215       return nullptr;
 216
 217     NextMetaPtr = getInstruction(Target);
 218   } else {
 219     NextMetaPtr =
 220         getInstruction(InstrMeta.VMAddress + InstrMeta.InstructionSize);
 221   }
 222
 223   if (!NextMetaPtr || !NextMetaPtr->Valid)
 224     return nullptr;
 225
 226   return NextMetaPtr;
 227 }
 228
 229 std::set<const Instr *>
 230 FileAnalysis::getDirectControlFlowXRefs(const Instr &InstrMeta) const {
 231   std::set<const Instr *> CFCrossReferences;
 232   const Instr *PrevInstruction = getPrevInstructionSequential(InstrMeta);
 233
 234   if (PrevInstruction && canFallThrough(*PrevInstruction))
 235     CFCrossReferences.insert(PrevInstruction);
 236
 237   const auto &TargetRefsKV = StaticBranchTargetings.find(InstrMeta.VMAddress);
 238   if (TargetRefsKV == StaticBranchTargetings.end())
 239     return CFCrossReferences;
 240
 241   for (uint64_t SourceInstrAddress : TargetRefsKV->second) {
 242     const auto &SourceInstrKV = Instructions.find(SourceInstrAddress);
 243     if (SourceInstrKV == Instructions.end()) {
 244       errs() << "Failed to find source instruction at address "
 245              << format_hex(SourceInstrAddress, 2)
 246              << " for the cross-reference to instruction at address "
 247              << format_hex(InstrMeta.VMAddress, 2) << ".\n";
 248       continue;
 249     }
 250
 251     CFCrossReferences.insert(&SourceInstrKV->second);
 252   }
 253
 254   return CFCrossReferences;
 255 }
 256
 257 const std::set<object::SectionedAddress> &
 258 FileAnalysis::getIndirectInstructions() const {
 259   return IndirectInstructions;
 260 }
 261
 262 const MCRegisterInfo *FileAnalysis::getRegisterInfo() const {
 263   return RegisterInfo.get();
 264 }
 265
 266 const MCInstrInfo *FileAnalysis::getMCInstrInfo() const { return MII.get(); }
 267
 268 const MCInstrAnalysis *FileAnalysis::getMCInstrAnalysis() const {
 269   return MIA.get();
 270 }
 271
 272 Expected<DIInliningInfo>
 273 FileAnalysis::symbolizeInlinedCode(object::SectionedAddress Address) {
 274   assert(Symbolizer != nullptr && "Symbolizer is invalid.");
 275
 276   return Symbolizer->symbolizeInlinedCode(Object->getFileName(), Address);
 277 }
 278
 279 CFIProtectionStatus
 280 FileAnalysis::validateCFIProtection(const GraphResult &Graph) const {
 281   const Instr *InstrMetaPtr = getInstruction(Graph.BaseAddress);
 282   if (!InstrMetaPtr)
 283     return CFIProtectionStatus::FAIL_INVALID_INSTRUCTION;
 284
 285   const auto &InstrDesc = MII->get(InstrMetaPtr->Instruction.getOpcode());
 286   if (!InstrDesc.mayAffectControlFlow(InstrMetaPtr->Instruction, *RegisterInfo))
 287     return CFIProtectionStatus::FAIL_NOT_INDIRECT_CF;
 288
 289   if (!usesRegisterOperand(*InstrMetaPtr))
 290     return CFIProtectionStatus::FAIL_NOT_INDIRECT_CF;
 291
 292   if (!Graph.OrphanedNodes.empty())
 293     return CFIProtectionStatus::FAIL_ORPHANS;
 294
 295   for (const auto &BranchNode : Graph.ConditionalBranchNodes) {
 296     if (!BranchNode.CFIProtection)
 297       return CFIProtectionStatus::FAIL_BAD_CONDITIONAL_BRANCH;
 298   }
 299
 300   if (indirectCFOperandClobber(Graph) != Graph.BaseAddress)
 301     return CFIProtectionStatus::FAIL_REGISTER_CLOBBERED;
 302
 303   return CFIProtectionStatus::PROTECTED;
 304 }
 305
 306 uint64_t FileAnalysis::indirectCFOperandClobber(const GraphResult &Graph) const {
 307   assert(Graph.OrphanedNodes.empty() && "Orphaned nodes should be empty.");
 308
 309   // Get the set of registers we must check to ensure they're not clobbered.
 310   const Instr &IndirectCF = getInstructionOrDie(Graph.BaseAddress);
 311   DenseSet<unsigned> RegisterNumbers;
 312   for (const auto &Operand : IndirectCF.Instruction) {
 313     if (Operand.isReg())
 314       RegisterNumbers.insert(Operand.getReg());
 315   }
 316   assert(RegisterNumbers.size() && "Zero register operands on indirect CF.");
 317
 318   // Now check all branches to indirect CFs and ensure no clobbering happens.
 319   for (const auto &Branch : Graph.ConditionalBranchNodes) {
 320     uint64_t Node;
 321     if (Branch.IndirectCFIsOnTargetPath)
 322       Node = Branch.Target;
 323     else
 324       Node = Branch.Fallthrough;
 325
 326     // Some architectures (e.g., AArch64) cannot load in an indirect branch, so
 327     // we allow them one load.
 328     bool canLoad = !MII->get(IndirectCF.Instruction.getOpcode()).mayLoad();
 329
 330     // We walk backwards from the indirect CF.  It is the last node returned by
 331     // Graph.flattenAddress, so we skip it since we already handled it.
 332     DenseSet<unsigned> CurRegisterNumbers = RegisterNumbers;
 333     std::vector<uint64_t> Nodes = Graph.flattenAddress(Node);
 334     for (auto I = Nodes.rbegin() + 1, E = Nodes.rend(); I != E; ++I) {
 335       Node = *I;
 336       const Instr &NodeInstr = getInstructionOrDie(Node);
 337       const auto &InstrDesc = MII->get(NodeInstr.Instruction.getOpcode());
 338
 339       for (auto RI = CurRegisterNumbers.begin(), RE = CurRegisterNumbers.end();
 340            RI != RE; ++RI) {
 341         unsigned RegNum = *RI;
 342         if (InstrDesc.hasDefOfPhysReg(NodeInstr.Instruction, RegNum,
 343                                       *RegisterInfo)) {
 344           if (!canLoad || !InstrDesc.mayLoad())
 345             return Node;
 346           canLoad = false;
 347           CurRegisterNumbers.erase(RI);
 348           // Add the registers this load reads to those we check for clobbers.
 349           for (unsigned i = InstrDesc.getNumDefs(),
 350                         e = InstrDesc.getNumOperands(); i != e; i++) {
 351             const auto Operand = NodeInstr.Instruction.getOperand(i);
 352             if (Operand.isReg())
 353               CurRegisterNumbers.insert(Operand.getReg());
 354           }
 355           break;
 356         }
 357       }
 358     }
 359   }
 360
 361   return Graph.BaseAddress;
 362 }
 363
 364 void FileAnalysis::printInstruction(const Instr &InstrMeta,
 365                                     raw_ostream &OS) const {
 366   Printer->printInst(&InstrMeta.Instruction, OS, "", *SubtargetInfo.get());
 367 }
 368
 369 Error FileAnalysis::initialiseDisassemblyMembers() {
 370   std::string TripleName = ObjectTriple.getTriple();
 371   ArchName = "";
 372   MCPU = "";
 373   std::string ErrorString;
 374
 375   Symbolizer.reset(new LLVMSymbolizer());
 376
 377   ObjectTarget =
 378       TargetRegistry::lookupTarget(ArchName, ObjectTriple, ErrorString);
 379   if (!ObjectTarget)
 380     return make_error<UnsupportedDisassembly>(
 381         (Twine("Couldn't find target \"") + ObjectTriple.getTriple() +
 382          "\", failed with error: " + ErrorString)
 383             .str());
 384
 385   RegisterInfo.reset(ObjectTarget->createMCRegInfo(TripleName));
 386   if (!RegisterInfo)
 387     return make_error<UnsupportedDisassembly>(
 388         "Failed to initialise RegisterInfo.");
 389
 390   AsmInfo.reset(ObjectTarget->createMCAsmInfo(*RegisterInfo, TripleName));
 391   if (!AsmInfo)
 392     return make_error<UnsupportedDisassembly>("Failed to initialise AsmInfo.");
 393
 394   SubtargetInfo.reset(ObjectTarget->createMCSubtargetInfo(
 395       TripleName, MCPU, Features.getString()));
 396   if (!SubtargetInfo)
 397     return make_error<UnsupportedDisassembly>(
 398         "Failed to initialise SubtargetInfo.");
 399
 400   MII.reset(ObjectTarget->createMCInstrInfo());
 401   if (!MII)
 402     return make_error<UnsupportedDisassembly>("Failed to initialise MII.");
 403
 404   Context.reset(new MCContext(AsmInfo.get(), RegisterInfo.get(), &MOFI));
 405
 406   Disassembler.reset(
 407       ObjectTarget->createMCDisassembler(*SubtargetInfo, *Context));
 408
 409   if (!Disassembler)
 410     return make_error<UnsupportedDisassembly>(
 411         "No disassembler available for target");
 412
 413   MIA.reset(ObjectTarget->createMCInstrAnalysis(MII.get()));
 414
 415   Printer.reset(ObjectTarget->createMCInstPrinter(
 416       ObjectTriple, AsmInfo->getAssemblerDialect(), *AsmInfo, *MII,
 417       *RegisterInfo));
 418
 419   return Error::success();
 420 }
 421
 422 Error FileAnalysis::parseCodeSections() {
 423   if (!IgnoreDWARFFlag) {
 424     std::unique_ptr<DWARFContext> DWARF = DWARFContext::create(*Object);
 425     if (!DWARF)
 426       return make_error<StringError>("Could not create DWARF information.",
 427                                      inconvertibleErrorCode());
 428
 429     bool LineInfoValid = false;
 430
 431     for (auto &Unit : DWARF->compile_units()) {
 432       const auto &LineTable = DWARF->getLineTableForUnit(Unit.get());
 433       if (LineTable && !LineTable->Rows.empty()) {
 434         LineInfoValid = true;
 435         break;
 436       }
 437     }
 438
 439     if (!LineInfoValid)
 440       return make_error<StringError>(
 441           "DWARF line information missing. Did you compile with '-g'?",
 442           inconvertibleErrorCode());
 443   }
 444
 445   for (const object::SectionRef &Section : Object->sections()) {
 446     // Ensure only executable sections get analysed.
 447     if (!(object::ELFSectionRef(Section).getFlags() & ELF::SHF_EXECINSTR))
 448       continue;
 449
 450     // Avoid checking the PLT since it produces spurious failures on AArch64
 451     // when ignoring DWARF data.
 452     Expected<StringRef> NameOrErr = Section.getName();
 453     if (NameOrErr && *NameOrErr == ".plt")
 454       continue;
 455     consumeError(NameOrErr.takeError());
 456
 457     Expected<StringRef> Contents = Section.getContents();
 458     if (!Contents)
 459       return Contents.takeError();
 460     ArrayRef<uint8_t> SectionBytes = arrayRefFromStringRef(*Contents);
 461
 462     parseSectionContents(SectionBytes,
 463                          {Section.getAddress(), Section.getIndex()});
 464   }
 465   return Error::success();
 466 }
 467
 468 void FileAnalysis::parseSectionContents(ArrayRef<uint8_t> SectionBytes,
 469                                         object::SectionedAddress Address) {
 470   assert(Symbolizer && "Symbolizer is uninitialised.");
 471   MCInst Instruction;
 472   Instr InstrMeta;
 473   uint64_t InstructionSize;
 474
 475   for (uint64_t Byte = 0; Byte < SectionBytes.size();) {
 476     bool ValidInstruction =
 477         Disassembler->getInstruction(Instruction, InstructionSize,
 478                                      SectionBytes.drop_front(Byte), 0, nulls(),
 479                                      outs()) == MCDisassembler::Success;
 480
 481     Byte += InstructionSize;
 482
 483     uint64_t VMAddress = Address.Address + Byte - InstructionSize;
 484     InstrMeta.Instruction = Instruction;
 485     InstrMeta.VMAddress = VMAddress;
 486     InstrMeta.InstructionSize = InstructionSize;
 487     InstrMeta.Valid = ValidInstruction;
 488
 489     addInstruction(InstrMeta);
 490
 491     if (!ValidInstruction)
 492       continue;
 493
 494     // Skip additional parsing for instructions that do not affect the control
 495     // flow.
 496     const auto &InstrDesc = MII->get(Instruction.getOpcode());
 497     if (!InstrDesc.mayAffectControlFlow(Instruction, *RegisterInfo))
 498       continue;
 499
 500     uint64_t Target;
 501     if (MIA->evaluateBranch(Instruction, VMAddress, InstructionSize, Target)) {
 502       // If the target can be evaluated, it's not indirect.
 503       StaticBranchTargetings[Target].push_back(VMAddress);
 504       continue;
 505     }
 506
 507     if (!usesRegisterOperand(InstrMeta))
 508       continue;
 509
 510     if (InstrDesc.isReturn())
 511       continue;
 512
 513     // Check if this instruction exists in the range of the DWARF metadata.
 514     if (!IgnoreDWARFFlag) {
 515       auto LineInfo = Symbolizer->symbolizeCode(
 516           Object->getFileName(), {VMAddress, Address.SectionIndex});
 517       if (!LineInfo) {
 518         handleAllErrors(LineInfo.takeError(), [](const ErrorInfoBase &E) {
 519           errs() << "Symbolizer failed to get line: " << E.message() << "\n";
 520         });
 521         continue;
 522       }
 523
 524       if (LineInfo->FileName == DILineInfo::BadString)
 525         continue;
 526     }
 527
 528     IndirectInstructions.insert({VMAddress, Address.SectionIndex});
 529   }
 530 }
 531
 532 void FileAnalysis::addInstruction(const Instr &Instruction) {
 533   const auto &KV =
 534       Instructions.insert(std::make_pair(Instruction.VMAddress, Instruction));
 535   if (!KV.second) {
 536     errs() << "Failed to add instruction at address "
 537            << format_hex(Instruction.VMAddress, 2)
 538            << ": Instruction at this address already exists.\n";
 539     exit(EXIT_FAILURE);
 540   }
 541 }
 542
 543 Error FileAnalysis::parseSymbolTable() {
 544   // Functions that will trap on CFI violations.
 545   SmallSet<StringRef, 4> TrapOnFailFunctions;
 546   TrapOnFailFunctions.insert("__cfi_slowpath");
 547   TrapOnFailFunctions.insert("__cfi_slowpath_diag");
 548   TrapOnFailFunctions.insert("abort");
 549
 550   // Look through the list of symbols for functions that will trap on CFI
 551   // violations.
 552   for (auto &Sym : Object->symbols()) {
 553     auto SymNameOrErr = Sym.getName();
 554     if (!SymNameOrErr)
 555       consumeError(SymNameOrErr.takeError());
 556     else if (TrapOnFailFunctions.count(*SymNameOrErr) > 0) {
 557       auto AddrOrErr = Sym.getAddress();
 558       if (!AddrOrErr)
 559         consumeError(AddrOrErr.takeError());
 560       else
 561         TrapOnFailFunctionAddresses.insert(*AddrOrErr);
 562     }
 563   }
 564   if (auto *ElfObject = dyn_cast<object::ELFObjectFileBase>(Object)) {
 565     for (const auto &Addr : ElfObject->getPltAddresses()) {
 566       object::SymbolRef Sym(Addr.first, Object);
 567       auto SymNameOrErr = Sym.getName();
 568       if (!SymNameOrErr)
 569         consumeError(SymNameOrErr.takeError());
 570       else if (TrapOnFailFunctions.count(*SymNameOrErr) > 0)
 571         TrapOnFailFunctionAddresses.insert(Addr.second);
 572     }
 573   }
 574   return Error::success();
 575 }
 576
 577 UnsupportedDisassembly::UnsupportedDisassembly(StringRef Text) : Text(Text) {}
 578
 579 char UnsupportedDisassembly::ID;
 580 void UnsupportedDisassembly::log(raw_ostream &OS) const {
 581   OS << "Could not initialise disassembler: " << Text;
 582 }
 583
 584 std::error_code UnsupportedDisassembly::convertToErrorCode() const {
 585   return std::error_code();
 586 }
 587
 588 } // namespace cfi_verify
 589 } // namespace llvm