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/MC/MCTargetOptions.h"
26 #include "llvm/Object/Binary.h"
27 #include "llvm/Object/COFF.h"
28 #include "llvm/Object/ELFObjectFile.h"
29 #include "llvm/Object/ObjectFile.h"
30 #include "llvm/Support/Casting.h"
31 #include "llvm/Support/CommandLine.h"
32 #include "llvm/Support/Error.h"
33 #include "llvm/Support/MemoryBuffer.h"
34 #include "llvm/Support/TargetRegistry.h"
35 #include "llvm/Support/TargetSelect.h"
36 #include "llvm/Support/raw_ostream.h"
37 
38 
39 using Instr = llvm::cfi_verify::FileAnalysis::Instr;
40 using LLVMSymbolizer = llvm::symbolize::LLVMSymbolizer;
41 
42 namespace llvm {
43 namespace cfi_verify {
44 
45 bool IgnoreDWARFFlag;
46 
47 static cl::opt<bool, true> IgnoreDWARFArg(
48     "ignore-dwarf",
49     cl::desc(
50         "Ignore all DWARF data. This relaxes the requirements for all "
51         "statically linked libraries to have been compiled with '-g', but "
52         "will result in false positives for 'CFI unprotected' instructions."),
53     cl::location(IgnoreDWARFFlag), cl::init(false));
54 
stringCFIProtectionStatus(CFIProtectionStatus Status)55 StringRef stringCFIProtectionStatus(CFIProtectionStatus Status) {
56   switch (Status) {
57   case CFIProtectionStatus::PROTECTED:
58     return "PROTECTED";
59   case CFIProtectionStatus::FAIL_NOT_INDIRECT_CF:
60     return "FAIL_NOT_INDIRECT_CF";
61   case CFIProtectionStatus::FAIL_ORPHANS:
62     return "FAIL_ORPHANS";
63   case CFIProtectionStatus::FAIL_BAD_CONDITIONAL_BRANCH:
64     return "FAIL_BAD_CONDITIONAL_BRANCH";
65   case CFIProtectionStatus::FAIL_REGISTER_CLOBBERED:
66     return "FAIL_REGISTER_CLOBBERED";
67   case CFIProtectionStatus::FAIL_INVALID_INSTRUCTION:
68     return "FAIL_INVALID_INSTRUCTION";
69   }
70   llvm_unreachable("Attempted to stringify an unknown enum value.");
71 }
72 
Create(StringRef Filename)73 Expected<FileAnalysis> FileAnalysis::Create(StringRef Filename) {
74   // Open the filename provided.
75   Expected<object::OwningBinary<object::Binary>> BinaryOrErr =
76       object::createBinary(Filename);
77   if (!BinaryOrErr)
78     return BinaryOrErr.takeError();
79 
80   // Construct the object and allow it to take ownership of the binary.
81   object::OwningBinary<object::Binary> Binary = std::move(BinaryOrErr.get());
82   FileAnalysis Analysis(std::move(Binary));
83 
84   Analysis.Object = dyn_cast<object::ObjectFile>(Analysis.Binary.getBinary());
85   if (!Analysis.Object)
86     return make_error<UnsupportedDisassembly>("Failed to cast object");
87 
88   switch (Analysis.Object->getArch()) {
89     case Triple::x86:
90     case Triple::x86_64:
91     case Triple::aarch64:
92     case Triple::aarch64_be:
93       break;
94     default:
95       return make_error<UnsupportedDisassembly>("Unsupported architecture.");
96   }
97 
98   Analysis.ObjectTriple = Analysis.Object->makeTriple();
99   Analysis.Features = Analysis.Object->getFeatures();
100 
101   // Init the rest of the object.
102   if (auto InitResponse = Analysis.initialiseDisassemblyMembers())
103     return std::move(InitResponse);
104 
105   if (auto SectionParseResponse = Analysis.parseCodeSections())
106     return std::move(SectionParseResponse);
107 
108   if (auto SymbolTableParseResponse = Analysis.parseSymbolTable())
109     return std::move(SymbolTableParseResponse);
110 
111   return std::move(Analysis);
112 }
113 
FileAnalysis(object::OwningBinary<object::Binary> Binary)114 FileAnalysis::FileAnalysis(object::OwningBinary<object::Binary> Binary)
115     : Binary(std::move(Binary)) {}
116 
FileAnalysis(const Triple & ObjectTriple,const SubtargetFeatures & Features)117 FileAnalysis::FileAnalysis(const Triple &ObjectTriple,
118                            const SubtargetFeatures &Features)
119     : ObjectTriple(ObjectTriple), Features(Features) {}
120 
121 const Instr *
getPrevInstructionSequential(const Instr & InstrMeta) const122 FileAnalysis::getPrevInstructionSequential(const Instr &InstrMeta) const {
123   std::map<uint64_t, Instr>::const_iterator KV =
124       Instructions.find(InstrMeta.VMAddress);
125   if (KV == Instructions.end() || KV == Instructions.begin())
126     return nullptr;
127 
128   if (!(--KV)->second.Valid)
129     return nullptr;
130 
131   return &KV->second;
132 }
133 
134 const Instr *
getNextInstructionSequential(const Instr & InstrMeta) const135 FileAnalysis::getNextInstructionSequential(const Instr &InstrMeta) const {
136   std::map<uint64_t, Instr>::const_iterator KV =
137       Instructions.find(InstrMeta.VMAddress);
138   if (KV == Instructions.end() || ++KV == Instructions.end())
139     return nullptr;
140 
141   if (!KV->second.Valid)
142     return nullptr;
143 
144   return &KV->second;
145 }
146 
usesRegisterOperand(const Instr & InstrMeta) const147 bool FileAnalysis::usesRegisterOperand(const Instr &InstrMeta) const {
148   for (const auto &Operand : InstrMeta.Instruction) {
149     if (Operand.isReg())
150       return true;
151   }
152   return false;
153 }
154 
getInstruction(uint64_t Address) const155 const Instr *FileAnalysis::getInstruction(uint64_t Address) const {
156   const auto &InstrKV = Instructions.find(Address);
157   if (InstrKV == Instructions.end())
158     return nullptr;
159 
160   return &InstrKV->second;
161 }
162 
getInstructionOrDie(uint64_t Address) const163 const Instr &FileAnalysis::getInstructionOrDie(uint64_t Address) const {
164   const auto &InstrKV = Instructions.find(Address);
165   assert(InstrKV != Instructions.end() && "Address doesn't exist.");
166   return InstrKV->second;
167 }
168 
isCFITrap(const Instr & InstrMeta) const169 bool FileAnalysis::isCFITrap(const Instr &InstrMeta) const {
170   const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
171   return InstrDesc.isTrap() || willTrapOnCFIViolation(InstrMeta);
172 }
173 
willTrapOnCFIViolation(const Instr & InstrMeta) const174 bool FileAnalysis::willTrapOnCFIViolation(const Instr &InstrMeta) const {
175   const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
176   if (!InstrDesc.isCall())
177     return false;
178   uint64_t Target;
179   if (!MIA->evaluateBranch(InstrMeta.Instruction, InstrMeta.VMAddress,
180                            InstrMeta.InstructionSize, Target))
181     return false;
182   return TrapOnFailFunctionAddresses.count(Target) > 0;
183 }
184 
canFallThrough(const Instr & InstrMeta) const185 bool FileAnalysis::canFallThrough(const Instr &InstrMeta) const {
186   if (!InstrMeta.Valid)
187     return false;
188 
189   if (isCFITrap(InstrMeta))
190     return false;
191 
192   const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
193   if (InstrDesc.mayAffectControlFlow(InstrMeta.Instruction, *RegisterInfo))
194     return InstrDesc.isConditionalBranch();
195 
196   return true;
197 }
198 
199 const Instr *
getDefiniteNextInstruction(const Instr & InstrMeta) const200 FileAnalysis::getDefiniteNextInstruction(const Instr &InstrMeta) const {
201   if (!InstrMeta.Valid)
202     return nullptr;
203 
204   if (isCFITrap(InstrMeta))
205     return nullptr;
206 
207   const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
208   const Instr *NextMetaPtr;
209   if (InstrDesc.mayAffectControlFlow(InstrMeta.Instruction, *RegisterInfo)) {
210     if (InstrDesc.isConditionalBranch())
211       return nullptr;
212 
213     uint64_t Target;
214     if (!MIA->evaluateBranch(InstrMeta.Instruction, InstrMeta.VMAddress,
215                              InstrMeta.InstructionSize, Target))
216       return nullptr;
217 
218     NextMetaPtr = getInstruction(Target);
219   } else {
220     NextMetaPtr =
221         getInstruction(InstrMeta.VMAddress + InstrMeta.InstructionSize);
222   }
223 
224   if (!NextMetaPtr || !NextMetaPtr->Valid)
225     return nullptr;
226 
227   return NextMetaPtr;
228 }
229 
230 std::set<const Instr *>
getDirectControlFlowXRefs(const Instr & InstrMeta) const231 FileAnalysis::getDirectControlFlowXRefs(const Instr &InstrMeta) const {
232   std::set<const Instr *> CFCrossReferences;
233   const Instr *PrevInstruction = getPrevInstructionSequential(InstrMeta);
234 
235   if (PrevInstruction && canFallThrough(*PrevInstruction))
236     CFCrossReferences.insert(PrevInstruction);
237 
238   const auto &TargetRefsKV = StaticBranchTargetings.find(InstrMeta.VMAddress);
239   if (TargetRefsKV == StaticBranchTargetings.end())
240     return CFCrossReferences;
241 
242   for (uint64_t SourceInstrAddress : TargetRefsKV->second) {
243     const auto &SourceInstrKV = Instructions.find(SourceInstrAddress);
244     if (SourceInstrKV == Instructions.end()) {
245       errs() << "Failed to find source instruction at address "
246              << format_hex(SourceInstrAddress, 2)
247              << " for the cross-reference to instruction at address "
248              << format_hex(InstrMeta.VMAddress, 2) << ".\n";
249       continue;
250     }
251 
252     CFCrossReferences.insert(&SourceInstrKV->second);
253   }
254 
255   return CFCrossReferences;
256 }
257 
258 const std::set<object::SectionedAddress> &
getIndirectInstructions() const259 FileAnalysis::getIndirectInstructions() const {
260   return IndirectInstructions;
261 }
262 
getRegisterInfo() const263 const MCRegisterInfo *FileAnalysis::getRegisterInfo() const {
264   return RegisterInfo.get();
265 }
266 
getMCInstrInfo() const267 const MCInstrInfo *FileAnalysis::getMCInstrInfo() const { return MII.get(); }
268 
getMCInstrAnalysis() const269 const MCInstrAnalysis *FileAnalysis::getMCInstrAnalysis() const {
270   return MIA.get();
271 }
272 
273 Expected<DIInliningInfo>
symbolizeInlinedCode(object::SectionedAddress Address)274 FileAnalysis::symbolizeInlinedCode(object::SectionedAddress Address) {
275   assert(Symbolizer != nullptr && "Symbolizer is invalid.");
276 
277   return Symbolizer->symbolizeInlinedCode(Object->getFileName(), Address);
278 }
279 
280 CFIProtectionStatus
validateCFIProtection(const GraphResult & Graph) const281 FileAnalysis::validateCFIProtection(const GraphResult &Graph) const {
282   const Instr *InstrMetaPtr = getInstruction(Graph.BaseAddress);
283   if (!InstrMetaPtr)
284     return CFIProtectionStatus::FAIL_INVALID_INSTRUCTION;
285 
286   const auto &InstrDesc = MII->get(InstrMetaPtr->Instruction.getOpcode());
287   if (!InstrDesc.mayAffectControlFlow(InstrMetaPtr->Instruction, *RegisterInfo))
288     return CFIProtectionStatus::FAIL_NOT_INDIRECT_CF;
289 
290   if (!usesRegisterOperand(*InstrMetaPtr))
291     return CFIProtectionStatus::FAIL_NOT_INDIRECT_CF;
292 
293   if (!Graph.OrphanedNodes.empty())
294     return CFIProtectionStatus::FAIL_ORPHANS;
295 
296   for (const auto &BranchNode : Graph.ConditionalBranchNodes) {
297     if (!BranchNode.CFIProtection)
298       return CFIProtectionStatus::FAIL_BAD_CONDITIONAL_BRANCH;
299   }
300 
301   if (indirectCFOperandClobber(Graph) != Graph.BaseAddress)
302     return CFIProtectionStatus::FAIL_REGISTER_CLOBBERED;
303 
304   return CFIProtectionStatus::PROTECTED;
305 }
306 
indirectCFOperandClobber(const GraphResult & Graph) const307 uint64_t FileAnalysis::indirectCFOperandClobber(const GraphResult &Graph) const {
308   assert(Graph.OrphanedNodes.empty() && "Orphaned nodes should be empty.");
309 
310   // Get the set of registers we must check to ensure they're not clobbered.
311   const Instr &IndirectCF = getInstructionOrDie(Graph.BaseAddress);
312   DenseSet<unsigned> RegisterNumbers;
313   for (const auto &Operand : IndirectCF.Instruction) {
314     if (Operand.isReg())
315       RegisterNumbers.insert(Operand.getReg());
316   }
317   assert(RegisterNumbers.size() && "Zero register operands on indirect CF.");
318 
319   // Now check all branches to indirect CFs and ensure no clobbering happens.
320   for (const auto &Branch : Graph.ConditionalBranchNodes) {
321     uint64_t Node;
322     if (Branch.IndirectCFIsOnTargetPath)
323       Node = Branch.Target;
324     else
325       Node = Branch.Fallthrough;
326 
327     // Some architectures (e.g., AArch64) cannot load in an indirect branch, so
328     // we allow them one load.
329     bool canLoad = !MII->get(IndirectCF.Instruction.getOpcode()).mayLoad();
330 
331     // We walk backwards from the indirect CF.  It is the last node returned by
332     // Graph.flattenAddress, so we skip it since we already handled it.
333     DenseSet<unsigned> CurRegisterNumbers = RegisterNumbers;
334     std::vector<uint64_t> Nodes = Graph.flattenAddress(Node);
335     for (auto I = Nodes.rbegin() + 1, E = Nodes.rend(); I != E; ++I) {
336       Node = *I;
337       const Instr &NodeInstr = getInstructionOrDie(Node);
338       const auto &InstrDesc = MII->get(NodeInstr.Instruction.getOpcode());
339 
340       for (auto RI = CurRegisterNumbers.begin(), RE = CurRegisterNumbers.end();
341            RI != RE; ++RI) {
342         unsigned RegNum = *RI;
343         if (InstrDesc.hasDefOfPhysReg(NodeInstr.Instruction, RegNum,
344                                       *RegisterInfo)) {
345           if (!canLoad || !InstrDesc.mayLoad())
346             return Node;
347           canLoad = false;
348           CurRegisterNumbers.erase(RI);
349           // Add the registers this load reads to those we check for clobbers.
350           for (unsigned i = InstrDesc.getNumDefs(),
351                         e = InstrDesc.getNumOperands(); i != e; i++) {
352             const auto Operand = NodeInstr.Instruction.getOperand(i);
353             if (Operand.isReg())
354               CurRegisterNumbers.insert(Operand.getReg());
355           }
356           break;
357         }
358       }
359     }
360   }
361 
362   return Graph.BaseAddress;
363 }
364 
printInstruction(const Instr & InstrMeta,raw_ostream & OS) const365 void FileAnalysis::printInstruction(const Instr &InstrMeta,
366                                     raw_ostream &OS) const {
367   Printer->printInst(&InstrMeta.Instruction, 0, "", *SubtargetInfo.get(), OS);
368 }
369 
initialiseDisassemblyMembers()370 Error FileAnalysis::initialiseDisassemblyMembers() {
371   std::string TripleName = ObjectTriple.getTriple();
372   ArchName = "";
373   MCPU = "";
374   std::string ErrorString;
375 
376   Symbolizer.reset(new LLVMSymbolizer());
377 
378   ObjectTarget =
379       TargetRegistry::lookupTarget(ArchName, ObjectTriple, ErrorString);
380   if (!ObjectTarget)
381     return make_error<UnsupportedDisassembly>(
382         (Twine("Couldn't find target \"") + ObjectTriple.getTriple() +
383          "\", failed with error: " + ErrorString)
384             .str());
385 
386   RegisterInfo.reset(ObjectTarget->createMCRegInfo(TripleName));
387   if (!RegisterInfo)
388     return make_error<UnsupportedDisassembly>(
389         "Failed to initialise RegisterInfo.");
390 
391   MCTargetOptions MCOptions;
392   AsmInfo.reset(
393       ObjectTarget->createMCAsmInfo(*RegisterInfo, TripleName, MCOptions));
394   if (!AsmInfo)
395     return make_error<UnsupportedDisassembly>("Failed to initialise AsmInfo.");
396 
397   SubtargetInfo.reset(ObjectTarget->createMCSubtargetInfo(
398       TripleName, MCPU, Features.getString()));
399   if (!SubtargetInfo)
400     return make_error<UnsupportedDisassembly>(
401         "Failed to initialise SubtargetInfo.");
402 
403   MII.reset(ObjectTarget->createMCInstrInfo());
404   if (!MII)
405     return make_error<UnsupportedDisassembly>("Failed to initialise MII.");
406 
407   Context.reset(new MCContext(AsmInfo.get(), RegisterInfo.get(), &MOFI));
408 
409   Disassembler.reset(
410       ObjectTarget->createMCDisassembler(*SubtargetInfo, *Context));
411 
412   if (!Disassembler)
413     return make_error<UnsupportedDisassembly>(
414         "No disassembler available for target");
415 
416   MIA.reset(ObjectTarget->createMCInstrAnalysis(MII.get()));
417 
418   Printer.reset(ObjectTarget->createMCInstPrinter(
419       ObjectTriple, AsmInfo->getAssemblerDialect(), *AsmInfo, *MII,
420       *RegisterInfo));
421 
422   return Error::success();
423 }
424 
parseCodeSections()425 Error FileAnalysis::parseCodeSections() {
426   if (!IgnoreDWARFFlag) {
427     std::unique_ptr<DWARFContext> DWARF = DWARFContext::create(*Object);
428     if (!DWARF)
429       return make_error<StringError>("Could not create DWARF information.",
430                                      inconvertibleErrorCode());
431 
432     bool LineInfoValid = false;
433 
434     for (auto &Unit : DWARF->compile_units()) {
435       const auto &LineTable = DWARF->getLineTableForUnit(Unit.get());
436       if (LineTable && !LineTable->Rows.empty()) {
437         LineInfoValid = true;
438         break;
439       }
440     }
441 
442     if (!LineInfoValid)
443       return make_error<StringError>(
444           "DWARF line information missing. Did you compile with '-g'?",
445           inconvertibleErrorCode());
446   }
447 
448   for (const object::SectionRef &Section : Object->sections()) {
449     // Ensure only executable sections get analysed.
450     if (!(object::ELFSectionRef(Section).getFlags() & ELF::SHF_EXECINSTR))
451       continue;
452 
453     // Avoid checking the PLT since it produces spurious failures on AArch64
454     // when ignoring DWARF data.
455     Expected<StringRef> NameOrErr = Section.getName();
456     if (NameOrErr && *NameOrErr == ".plt")
457       continue;
458     consumeError(NameOrErr.takeError());
459 
460     Expected<StringRef> Contents = Section.getContents();
461     if (!Contents)
462       return Contents.takeError();
463     ArrayRef<uint8_t> SectionBytes = arrayRefFromStringRef(*Contents);
464 
465     parseSectionContents(SectionBytes,
466                          {Section.getAddress(), Section.getIndex()});
467   }
468   return Error::success();
469 }
470 
parseSectionContents(ArrayRef<uint8_t> SectionBytes,object::SectionedAddress Address)471 void FileAnalysis::parseSectionContents(ArrayRef<uint8_t> SectionBytes,
472                                         object::SectionedAddress Address) {
473   assert(Symbolizer && "Symbolizer is uninitialised.");
474   MCInst Instruction;
475   Instr InstrMeta;
476   uint64_t InstructionSize;
477 
478   for (uint64_t Byte = 0; Byte < SectionBytes.size();) {
479     bool ValidInstruction =
480         Disassembler->getInstruction(Instruction, InstructionSize,
481                                      SectionBytes.drop_front(Byte), 0,
482                                      outs()) == MCDisassembler::Success;
483 
484     Byte += InstructionSize;
485 
486     uint64_t VMAddress = Address.Address + Byte - InstructionSize;
487     InstrMeta.Instruction = Instruction;
488     InstrMeta.VMAddress = VMAddress;
489     InstrMeta.InstructionSize = InstructionSize;
490     InstrMeta.Valid = ValidInstruction;
491 
492     addInstruction(InstrMeta);
493 
494     if (!ValidInstruction)
495       continue;
496 
497     // Skip additional parsing for instructions that do not affect the control
498     // flow.
499     const auto &InstrDesc = MII->get(Instruction.getOpcode());
500     if (!InstrDesc.mayAffectControlFlow(Instruction, *RegisterInfo))
501       continue;
502 
503     uint64_t Target;
504     if (MIA->evaluateBranch(Instruction, VMAddress, InstructionSize, Target)) {
505       // If the target can be evaluated, it's not indirect.
506       StaticBranchTargetings[Target].push_back(VMAddress);
507       continue;
508     }
509 
510     if (!usesRegisterOperand(InstrMeta))
511       continue;
512 
513     if (InstrDesc.isReturn())
514       continue;
515 
516     // Check if this instruction exists in the range of the DWARF metadata.
517     if (!IgnoreDWARFFlag) {
518       auto LineInfo = Symbolizer->symbolizeCode(
519           Object->getFileName(), {VMAddress, Address.SectionIndex});
520       if (!LineInfo) {
521         handleAllErrors(LineInfo.takeError(), [](const ErrorInfoBase &E) {
522           errs() << "Symbolizer failed to get line: " << E.message() << "\n";
523         });
524         continue;
525       }
526 
527       if (LineInfo->FileName == DILineInfo::BadString)
528         continue;
529     }
530 
531     IndirectInstructions.insert({VMAddress, Address.SectionIndex});
532   }
533 }
534 
addInstruction(const Instr & Instruction)535 void FileAnalysis::addInstruction(const Instr &Instruction) {
536   const auto &KV =
537       Instructions.insert(std::make_pair(Instruction.VMAddress, Instruction));
538   if (!KV.second) {
539     errs() << "Failed to add instruction at address "
540            << format_hex(Instruction.VMAddress, 2)
541            << ": Instruction at this address already exists.\n";
542     exit(EXIT_FAILURE);
543   }
544 }
545 
parseSymbolTable()546 Error FileAnalysis::parseSymbolTable() {
547   // Functions that will trap on CFI violations.
548   SmallSet<StringRef, 4> TrapOnFailFunctions;
549   TrapOnFailFunctions.insert("__cfi_slowpath");
550   TrapOnFailFunctions.insert("__cfi_slowpath_diag");
551   TrapOnFailFunctions.insert("abort");
552 
553   // Look through the list of symbols for functions that will trap on CFI
554   // violations.
555   for (auto &Sym : Object->symbols()) {
556     auto SymNameOrErr = Sym.getName();
557     if (!SymNameOrErr)
558       consumeError(SymNameOrErr.takeError());
559     else if (TrapOnFailFunctions.count(*SymNameOrErr) > 0) {
560       auto AddrOrErr = Sym.getAddress();
561       if (!AddrOrErr)
562         consumeError(AddrOrErr.takeError());
563       else
564         TrapOnFailFunctionAddresses.insert(*AddrOrErr);
565     }
566   }
567   if (auto *ElfObject = dyn_cast<object::ELFObjectFileBase>(Object)) {
568     for (const auto &Addr : ElfObject->getPltAddresses()) {
569       object::SymbolRef Sym(Addr.first, Object);
570       auto SymNameOrErr = Sym.getName();
571       if (!SymNameOrErr)
572         consumeError(SymNameOrErr.takeError());
573       else if (TrapOnFailFunctions.count(*SymNameOrErr) > 0)
574         TrapOnFailFunctionAddresses.insert(Addr.second);
575     }
576   }
577   return Error::success();
578 }
579 
UnsupportedDisassembly(StringRef Text)580 UnsupportedDisassembly::UnsupportedDisassembly(StringRef Text) : Text(Text) {}
581 
582 char UnsupportedDisassembly::ID;
log(raw_ostream & OS) const583 void UnsupportedDisassembly::log(raw_ostream &OS) const {
584   OS << "Could not initialise disassembler: " << Text;
585 }
586 
convertToErrorCode() const587 std::error_code UnsupportedDisassembly::convertToErrorCode() const {
588   return std::error_code();
589 }
590 
591 } // namespace cfi_verify
592 } // namespace llvm
593