MC Helpers for llvm-cfi-verify.

[hctim]

Summary

Add instruction analysis and machinecode traversal helpers in preparation for control flow graph generation implementation.

[hctim]

Added getControlFlowXRefs() to FileVerifier, including the associated unit tests.

[hctim]

Implemented FileVerifier::getIndirectInstructions() and made it return a std::set.

[vlad.tsyrklevich]

Could this change and the follow-ons be uploaded as diffs from the previous change?

[hctim]

Updated diff to only contain changes from stack.

[hctim]

Fix gtest unsigned/signed comparison warnings.

[vlad.tsyrklevich]

tools/llvm-cfi-verify/FileVerifier.cpp

132

getOpcode() == Instruction::Undefined? Also, what if InstrMeta.Bad?

171

Here you don't check NextKV->second.bad but below you do, which should it be?

tools/llvm-cfi-verify/FileVerifier.h

90

s/flow/fall/

95

s/qua/que/

96

s/instruction/method/

[hctim]

Merged changes from previous in stack, updated for vlad.tsyrklevich's comments.

tools/llvm-cfi-verify/FileVerifier.cpp

132

Made it more clear, this should only return true when the provided instruction is a trap used by CFI.

171

Should be both. Updated the unit test for this.

[hctim]

Merge prev in stack.

[hctim]

clang format

[vlad.tsyrklevich]

tools/llvm-cfi-verify/FileAnalysis.cpp

149 ↗

(On Diff #117727)

Make this an if{}else{} that calculates a uint64_t Target so that the identical tails can be merged?

tools/llvm-cfi-verify/FileAnalysis.h

103 ↗

(On Diff #117727)

getDirectControlFlowXRefs()?

[hctim]

Updated from Vlad's comments

[hctim]

Backported usesRegisterOperand.

[hctim]

Merged updates from stack.

[hctim]

Merged unit test modifications up stack.

tools/llvm-cfi-verify/CMakeLists.txt

 set(LLVM_LINK_COMPONENTS
   AllTargetsAsmPrinters
   AllTargetsAsmParsers
   AllTargetsDescs
   AllTargetsDisassemblers
   AllTargetsInfos
   MC
   Object
   MCParser
   Object
   Support
   )
 
 add_llvm_tool(llvm-cfi-verify
   llvm-cfi-verify.cpp
+  FileVerifier.cpp
   )

tools/llvm-cfi-verify/FileVerifier.h

+//===- FileVerifier.h -------------------------------------------*- C++ -*-===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CFI_VERIFY_FILE_VERIFIER_H
+#define LLVM_CFI_VERIFY_FILE_VERIFIER_H
+
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDisassembler/MCDisassembler.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstPrinter.h"
+#include "llvm/MC/MCInstrAnalysis.h"
+#include "llvm/MC/MCInstrDesc.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/Object/Binary.h"
+#include "llvm/Object/COFF.h"
+#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <functional>
+#include <set>
+#include <string>
+#include <unordered_map>
+
+namespace llvm {
+namespace cfi_verify {
+
+// This class is used to verify CFI instrumentation of a single file.
+class FileVerifier {
+public:
+  // A metadata struct for an instruction.
+  struct Instr {
+    uint64_t VMAddress;       // Virtual memory address of this instruction.
+    MCInst Instruction;       // Instruction.
+    uint64_t InstructionSize; // Size of this instruction.
+    std::string SectionName;  // Section this instruction is found in.
+    bool Bad; // Is this instruction bad (in which case, Instr::Instruction is
+              // invalid).
+  };
+
+  // Construct a FileVerifier from a file path.
+  static Expected<FileVerifier> Create(StringRef Filename);
+
+  // Construct and take ownership of the supplied object. Do not use this
+  // constructor, prefer to use FileVerifier::Create instead.
+  FileVerifier(object::OwningBinary<object::Binary> Binary);
+  FileVerifier() = delete;
+  FileVerifier(const FileVerifier &) = delete;
+  FileVerifier(FileVerifier &&Other) = default;
+
+  Error printIndirectCFInstructions() const;
+
+  // Returns the instruction at the provided address. Returns nullptr if there
+  // is no instruction at the provided address.
+  const Instr *getInstruction(uint64_t Address) const;
+
+  // Returns the instruction at the provided adress, dying if the instruction is
+  // not found.
+  const Instr &getInstructionOrDie(uint64_t Address) const;
+
+  // Returns a pointer to the previous/next instruction in sequence,
+  // respectively. Retusn nullptr if the next/prev instruction doesn't exist, or
+  // if the provided instruction doesn't exist.
+  const Instr *getPrevInstructionSequential(const Instr &InstrMeta) const;
+  const Instr *getNextInstructionSequential(const Instr &InstrMeta) const;
+
+  // Returns the list of indirect instructions.
+  const std::vector<uint64_t> &getIndirectInstructions() const;
+
+  // Returns whether this instruction is an undefined instruction (used in
+  // branch-to-undefined CFI protections).
+  bool isUndefinedInstruction(const Instr &InstrMeta) const;
+
+  // Returns whether this function can fall through to the next instruction.
+  // Undefined (and bad) instructions cannot fall through, and instruction that
+  // modify the control flow can only flow through if they are conditional
+  // branches or calls.
+  bool canFallThrough(const Instr &InstrMeta) const;
+
+  // Returns the definitive next instruction. This is different from the next
+  // instruction sequantially as it will follow unconditional branches (assuming
+  // they can be resolved at compile time, i.e. not indirect). This instruction
+  // returns nullptr if the provided instruction does not transfer control flow
+  // to exactly one instruction that is known deterministically at compile time.
+  // Also returns nullptr if the deterministic target does not exist in this
+  // file.
+  const Instr *getDefiniteNextInstruction(const Instr &InstrMeta) const;
+
+  // Get a list of deterministic control flows that lead to the provided
+  // instruction. This list includes all static control flow cross-references as
+  // well as the previous instruction if it can fall through.
+  std::set<const Instr *> getControlFlowXRefs(const Instr &InstrMeta) const;
+
+protected:
+  // Construct a blank object with the provided triple and features. Used in
+  // testing, where a sub class will dependency inject protected methods to
+  // allow analysis of raw binary, without requiring a fully valid ELF file.
+  FileVerifier(const Triple &ObjectTriple, const SubtargetFeatures &Features);
+
+  // Add an instruction to this object.
+  void addInstruction(const Instr &Instruction);
+
+  // Disassemble and parse the provided bytes into this object. Instruction
+  // address calculation is done relative to the provided SectionAddress, and
+  // instruction metadata is populated with the given section name.
+  void parseSectionContents(ArrayRef<uint8_t> SectionBytes,
+                            uint64_t SectionAddress, StringRef SectionName);
+
+  // Constructs and initialises members required for disassembly.
+  Error initialiseDisassemblyMembers();
+
+  // Parses code sections from the internal object file. Saves them into the
+  // internal members. Should only be called once by Create().
+  Error parseCodeSections();
+
+private:
+  // Members that describe the input file.
+  object::OwningBinary<object::Binary> Binary;
+  const object::ObjectFile *Object = nullptr;
+  Triple ObjectTriple;
+  std::string ArchName;
+  std::string MCPU;
+  const Target *ObjectTarget = nullptr;
+  SubtargetFeatures Features;
+
+  // Members required for disassembly.
+  std::unique_ptr<const MCRegisterInfo> RegisterInfo;
+  std::unique_ptr<const MCAsmInfo> AsmInfo;
+  std::unique_ptr<MCSubtargetInfo> SubtargetInfo;
+  std::unique_ptr<const MCInstrInfo> MII;
+  MCObjectFileInfo MOFI;
+  std::unique_ptr<MCContext> Context;
+  std::unique_ptr<const MCDisassembler> Disassembler;
+  std::unique_ptr<const MCInstrAnalysis> MIA;
+  std::unique_ptr<MCInstPrinter> Printer;
+
+  // A mapping between the virtual memory address to the instruction metadata
+  // struct.
+  std::map<uint64_t, Instr> Instructions;
+
+  // Contains a mapping between a specific address, and a list of instructions
+  // that use this address as a branch target (including call instructions).
+  std::unordered_map<uint64_t, std::vector<uint64_t>> StaticBranchTargetings;
+
+  // A list of addresses of indirect control flow instructions.
+  std::set<uint64_t> IndirectInstructions;
+};
+
+class UnsupportedDisassembly : public ErrorInfo<UnsupportedDisassembly> {
+public:
+  static char ID;
+
+  void log(raw_ostream &OS) const override;
+  std::error_code convertToErrorCode() const override;
+};
+
+} // namespace cfi_verify
+} // namespace llvm
+
+#endif // LLVM_CFI_VERIFY_FILE_VERIFIER_H

tools/llvm-cfi-verify/FileVerifier.cpp

+#include "FileVerifier.h"
+
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDisassembler/MCDisassembler.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstPrinter.h"
+#include "llvm/MC/MCInstrAnalysis.h"
+#include "llvm/MC/MCInstrDesc.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/Object/Binary.h"
+#include "llvm/Object/COFF.h"
+#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/FormatVariadic.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <functional>
+
+using Instr = llvm::cfi_verify::FileVerifier::Instr;
+
+namespace llvm {
+namespace cfi_verify {
+
+Expected<FileVerifier> FileVerifier::Create(StringRef Filename) {
+  // Open the filename provided.
+  Expected<object::OwningBinary<object::Binary>> BinaryOrErr =
+      object::createBinary(Filename);
+  if (!BinaryOrErr)
+    return BinaryOrErr.takeError();
+
+  // Construct the object and allow it to take ownership of the binary.
+  object::OwningBinary<object::Binary> Binary = std::move(BinaryOrErr.get());
+  FileVerifier Verifier(std::move(Binary));
+
+  Verifier.Object = dyn_cast<object::ObjectFile>(Verifier.Binary.getBinary());
+  if (!Verifier.Object)
+    return make_error<UnsupportedDisassembly>();
+
+  Verifier.ObjectTriple = Verifier.Object->makeTriple();
+  Verifier.Features = Verifier.Object->getFeatures();
+
+  // Init the rest of the object.
+  auto InitResponse = Verifier.initialiseDisassemblyMembers();
+  if (InitResponse)
+    return std::move(InitResponse);
+
+  auto SectionParseResponse = Verifier.parseCodeSections();
+  if (SectionParseResponse)
+    return std::move(SectionParseResponse);
+
+  return std::move(Verifier);
+}
+
+FileVerifier::FileVerifier(object::OwningBinary<object::Binary> Binary)
+    : Binary(std::move(Binary)) {}
+
+FileVerifier::FileVerifier(const Triple &ObjectTriple,
+                           const SubtargetFeatures &Features)
+    : ObjectTriple(ObjectTriple), Features(Features) {}
+
+Error FileVerifier::printIndirectCFInstructions() const {
+  for (const auto &Address : IndirectInstructions) {
+    const auto &InstructionKV = Instructions.find(Address);
+    if (InstructionKV == Instructions.end())
+      return make_error<StringError>(
+          formatv("No instruction found at address {0:x}", Address),
+          inconvertibleErrorCode());
+
+    const auto &InstrMeta = InstructionKV->second;
+    outs() << format_hex(Address, 2) << " [" << InstrMeta.SectionName
+           << "] = " << MII->getName(InstrMeta.Instruction.getOpcode()) << " ";
+    InstrMeta.Instruction.print(outs());
+    outs() << "\n";
+  }
+
+  return Error::success();
+}
+
+const Instr *
+FileVerifier::getPrevInstructionSequential(const Instr &InstrMeta) const {
+  std::map<uint64_t, Instr>::const_iterator KV =
+      Instructions.find(InstrMeta.VMAddress);
+  if (KV == Instructions.end() || KV == Instructions.begin())
+    return nullptr;
+
+  if ((--KV)->second.Bad)
+    return nullptr;
+
+  return &KV->second;
+}
+
+const Instr *
+FileVerifier::getNextInstructionSequential(const Instr &InstrMeta) const {
+  std::map<uint64_t, Instr>::const_iterator KV =
+      Instructions.find(InstrMeta.VMAddress);
+
+  if (KV++ == Instructions.end() || KV == Instructions.end())
+    return nullptr;
+
+  if (KV->second.Bad)
+    return nullptr;
+
+  return &KV->second;
+}
+
+const Instr *FileVerifier::getInstruction(uint64_t Address) const {
+  const auto &InstrKV = Instructions.find(Address);
+  if (InstrKV == Instructions.end())
+    return nullptr;
+
+  return &InstrKV->second;
+}
+
+const Instr &FileVerifier::getInstructionOrDie(uint64_t Address) const {
+  const auto &InstrKV = Instructions.find(Address);
+  assert(InstrKV != Instructions.end() && "Address doesn't exist.");
+  return InstrKV->second;
+}
+
+bool FileVerifier::isUndefinedInstruction(const Instr &InstrMeta) const {
+  return MII->getName(InstrMeta.Instruction.getOpcode()) == "TRAP";
+}
+
+bool FileVerifier::canFallThrough(const Instr &InstrMeta) const {
+  if (InstrMeta.Bad)
+    return false;
+
+  if (isUndefinedInstruction(InstrMeta))
+    return false;
+
+  const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
+  if (InstrDesc.mayAffectControlFlow(InstrMeta.Instruction, *RegisterInfo))
+    return InstrDesc.isConditionalBranch();
+
+  return true;
+}
+
+const Instr *
+FileVerifier::getDefiniteNextInstruction(const Instr &InstrMeta) const {
+  if (InstrMeta.Bad)
+    return nullptr;
+
+  if (isUndefinedInstruction(InstrMeta))
+    return nullptr;
+
+  const auto &InstrDesc = MII->get(InstrMeta.Instruction.getOpcode());
+  if (InstrDesc.mayAffectControlFlow(InstrMeta.Instruction, *RegisterInfo)) {
+    if (InstrDesc.isConditionalBranch())
+      return nullptr;
+
+    uint64_t Target;
+    if (!MIA->evaluateBranch(InstrMeta.Instruction, InstrMeta.VMAddress,
+                             InstrMeta.InstructionSize, Target))
+      return nullptr;
+
+    const auto &NextKV = Instructions.find(Target);
+    if (NextKV == Instructions.end())
+      return nullptr;
+
+    return &NextKV->second;
+  }
+
+  const auto &NextKV =
+      Instructions.find(InstrMeta.VMAddress + InstrMeta.InstructionSize);
+  if (NextKV == Instructions.end())
+    return nullptr;
+
+  if (NextKV->second.Bad)
+    return nullptr;
+
+  return &NextKV->second;
+}
+
+std::set<const Instr *>
+FileVerifier::getControlFlowXRefs(const Instr &InstrMeta) const {
+  std::set<const Instr *> CFCrossReferences;
+  const Instr *PrevInstruction = getPrevInstructionSequential(InstrMeta);
+
+  if (PrevInstruction && canFallThrough(*PrevInstruction))
+    CFCrossReferences.insert(PrevInstruction);
+
+  const auto &TargetRefsKV = StaticBranchTargetings.find(InstrMeta.VMAddress);
+  if (TargetRefsKV == StaticBranchTargetings.end())
+    return CFCrossReferences;
+
+  for (uint64_t SourceInstrAddress : TargetRefsKV->second) {
+    const auto &SourceInstrKV = Instructions.find(SourceInstrAddress);
+    if (SourceInstrKV == Instructions.end()) {
+      errs() << "Failed to find source instruction at address "
+             << format_hex(SourceInstrAddress, 2)
+             << " for the cross-reference to instruction at address "
+             << format_hex(InstrMeta.VMAddress, 2) << ".\n";
+      continue;
+    }
+
+    CFCrossReferences.insert(&SourceInstrKV->second);
+  }
+
+  return CFCrossReferences;
+}
+
+Error FileVerifier::initialiseDisassemblyMembers() {
+  std::string TripleName = ObjectTriple.getTriple();
+  ArchName = "";
+  MCPU = "";
+
+  std::string ErrorString;
+
+  ObjectTarget =
+      TargetRegistry::lookupTarget(ArchName, ObjectTriple, ErrorString);
+
+  if (!ObjectTarget)
+    return make_error<StringError>(Twine("Couldn't find target \"") +
+                                       ObjectTriple.getTriple() +
+                                       "\", failed with error: " + ErrorString,
+                                   inconvertibleErrorCode());
+
+  RegisterInfo.reset(ObjectTarget->createMCRegInfo(TripleName));
+  if (!RegisterInfo)
+    return make_error<StringError>("Failed to initialise RegisterInfo.",
+                                   inconvertibleErrorCode());
+
+  AsmInfo.reset(ObjectTarget->createMCAsmInfo(*RegisterInfo, TripleName));
+  if (!AsmInfo)
+    return make_error<StringError>("Failed to initialise AsmInfo.",
+                                   inconvertibleErrorCode());
+
+  SubtargetInfo.reset(ObjectTarget->createMCSubtargetInfo(
+      TripleName, MCPU, Features.getString()));
+  if (!SubtargetInfo)
+    return make_error<StringError>("Failed to initialise SubtargetInfo.",
+                                   inconvertibleErrorCode());
+
+  MII.reset(ObjectTarget->createMCInstrInfo());
+  if (!MII)
+    return make_error<StringError>("Failed to initialise MII.",
+                                   inconvertibleErrorCode());
+
+  Context.reset(new MCContext(AsmInfo.get(), RegisterInfo.get(), &MOFI));
+
+  Disassembler.reset(
+      ObjectTarget->createMCDisassembler(*SubtargetInfo, *Context));
+
+  if (!Disassembler)
+    return make_error<StringError>("No disassembler available for target",
+                                   inconvertibleErrorCode());
+
+  MIA.reset(ObjectTarget->createMCInstrAnalysis(MII.get()));
+
+  Printer.reset(ObjectTarget->createMCInstPrinter(
+      ObjectTriple, AsmInfo->getAssemblerDialect(), *AsmInfo, *MII,
+      *RegisterInfo));
+
+  return Error::success();
+}
+
+Error FileVerifier::parseCodeSections() {
+  for (const object::SectionRef &Section : Object->sections()) {
+    // Ensure only executable sections get analysed.
+    if (!(object::ELFSectionRef(Section).getFlags() & ELF::SHF_EXECINSTR))
+      continue;
+
+    StringRef SectionContents;
+    if (Section.getContents(SectionContents))
+      return make_error<StringError>("Failed to retrieve section contents",
+                                     inconvertibleErrorCode());
+
+    StringRef SectionName;
+    if (Section.getName(SectionName))
+      SectionName = "UNKNOWN";
+
+    ArrayRef<uint8_t> SectionBytes((const uint8_t *)SectionContents.data(),
+                                   Section.getSize());
+    parseSectionContents(SectionBytes, Section.getAddress(), SectionName);
+  }
+  return Error::success();
+}
+
+void FileVerifier::parseSectionContents(ArrayRef<uint8_t> SectionBytes,
+                                        uint64_t SectionAddress,
+                                        StringRef SectionName) {
+  MCInst Instruction;
+  Instr InstrMeta;
+  uint64_t InstructionSize;
+
+  for (uint64_t Byte = 0; Byte < SectionBytes.size();) {
+    bool BadInstruction = false;
+
+    SectionBytes.drop_front(Byte);
+
+    // Disassemble the instruction.
+    if (Disassembler->getInstruction(Instruction, InstructionSize,
+                                     SectionBytes.drop_front(Byte), 0, nulls(),
+                                     outs()) != MCDisassembler::Success)
+      BadInstruction = true;
+
+    Byte += InstructionSize;
+
+    uint64_t VMAddress = SectionAddress + Byte - InstructionSize;
+    InstrMeta.Instruction = Instruction;
+    InstrMeta.VMAddress = VMAddress;
+    InstrMeta.InstructionSize = InstructionSize;
+    InstrMeta.SectionName = SectionName;
+    InstrMeta.Bad = false;
+
+    if (BadInstruction) {
+      InstrMeta.Bad = true;
+      addInstruction(InstrMeta);
+      continue;
+    }
+
+    addInstruction(InstrMeta);
+
+    // Skip additional parsing for instructions that do not affect the control
+    // flow.
+    const auto &InstrDesc = MII->get(Instruction.getOpcode());
+    if (!InstrDesc.mayAffectControlFlow(Instruction, *RegisterInfo))
+      continue;
+
+    uint64_t Target;
+    if (MIA->evaluateBranch(Instruction, VMAddress, InstructionSize, Target)) {
+      // If the target can be evaluated, it's not indirect.
+      StaticBranchTargetings[Target].push_back(VMAddress);
+      continue;
+    }
+
+    // Skip instructions that do not operate on register operands.
+    bool UsesRegisterOperand = false;
+    for (const auto &Operand : Instruction) {
+      if (Operand.isReg())
+        UsesRegisterOperand = true;
+    }
+
+    if (!UsesRegisterOperand)
+      continue;
+
+    IndirectInstructions.insert(VMAddress);
+  }
+}
+
+void FileVerifier::addInstruction(const Instr &Instruction) {
+  Instructions[Instruction.VMAddress] = Instruction;
+}
+
+char UnsupportedDisassembly::ID;
+void UnsupportedDisassembly::log(raw_ostream &OS) const {
+  OS << "Dissassembling of non-objects not currently supported.\n";
+}
+
+std::error_code UnsupportedDisassembly::convertToErrorCode() const {
+  return std::error_code();
+}
+
+} // namespace cfi_verify
+} // namespace llvm

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

 // information.
 //
 // This tool is currently incomplete. It currently only does disassembly for
 // object files, and searches through the code for indirect control flow
 // instructions, printing them once found.
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/MC/MCAsmInfo.h"
-#include "llvm/MC/MCContext.h"
-#include "llvm/MC/MCDisassembler/MCDisassembler.h"
-#include "llvm/MC/MCInst.h"
-#include "llvm/MC/MCInstPrinter.h"
-#include "llvm/MC/MCInstrAnalysis.h"
-#include "llvm/MC/MCInstrDesc.h"
-#include "llvm/MC/MCInstrInfo.h"
-#include "llvm/MC/MCObjectFileInfo.h"
-#include "llvm/MC/MCRegisterInfo.h"
-#include "llvm/MC/MCSubtargetInfo.h"
-#include "llvm/Object/Binary.h"
-#include "llvm/Object/COFF.h"
-#include "llvm/Object/ObjectFile.h"
-#include "llvm/Support/Casting.h"
+#include "FileVerifier.h"
+
+#include "llvm/BinaryFormat/ELF.h"
 #include "llvm/Support/CommandLine.h"
-#include "llvm/Support/MemoryBuffer.h"
-#include "llvm/Support/TargetRegistry.h"
-#include "llvm/Support/TargetSelect.h"
-#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Error.h"
 
-#include <cassert>
 #include <cstdlib>
 
 using namespace llvm;
 using namespace llvm::object;
+using namespace llvm::cfi_verify;
 
-cl::opt<bool> ArgDumpSymbols("sym", cl::desc("Dump the symbol table."));
 cl::opt<std::string> InputFilename(cl::Positional, cl::desc("<input file>"),
                                    cl::Required);
 
-static void printSymbols(const ObjectFile *Object) {
-  for (const SymbolRef &Symbol : Object->symbols()) {
-    outs() << "Symbol [" << format_hex_no_prefix(Symbol.getValue(), 2)
-           << "] = ";
-
-    auto SymbolName = Symbol.getName();
-    if (SymbolName)
-      outs() << *SymbolName;
-    else
-      outs() << "UNKNOWN";
-
-    if (Symbol.getFlags() & SymbolRef::SF_Hidden)
-      outs() << " .hidden";
-
-    outs() << " (Section = ";
-
-    auto SymbolSection = Symbol.getSection();
-    if (SymbolSection) {
-      StringRef SymbolSectionName;
-      if ((*SymbolSection)->getName(SymbolSectionName))
-        outs() << "UNKNOWN)";
-      else
-        outs() << SymbolSectionName << ")";
-    } else {
-      outs() << "N/A)";
-    }
-
-    outs() << "\n";
-  }
-}
+ExitOnError ExitOnErr;
 
 int main(int argc, char **argv) {
   cl::ParseCommandLineOptions(argc, argv);
 
   InitializeAllTargetInfos();
   InitializeAllTargetMCs();
   InitializeAllAsmParsers();
   InitializeAllDisassemblers();
 
-  Expected<OwningBinary<Binary>> BinaryOrErr = createBinary(InputFilename);
-  if (!BinaryOrErr) {
-    errs() << "Failed to open file.\n";
-    return EXIT_FAILURE;
-  }
-
-  Binary &Binary = *BinaryOrErr.get().getBinary();
-  ObjectFile *Object = dyn_cast<ObjectFile>(&Binary);
-  if (!Object) {
-    errs() << "Disassembling of non-objects not currently supported.\n";
-    return EXIT_FAILURE;
-  }
-
-  Triple TheTriple = Object->makeTriple();
-  std::string TripleName = TheTriple.getTriple();
-  std::string ArchName = "";
-  std::string ErrorString;
-
-  const Target *TheTarget =
-      TargetRegistry::lookupTarget(ArchName, TheTriple, ErrorString);
-
-  if (!TheTarget) {
-    errs() << "Couldn't find target \"" << TheTriple.getTriple()
-           << "\", failed with error: " << ErrorString << ".\n";
-    return EXIT_FAILURE;
-  }
-
-  SubtargetFeatures Features = Object->getFeatures();
-
-  std::unique_ptr<const MCRegisterInfo> RegisterInfo(
-      TheTarget->createMCRegInfo(TripleName));
-  if (!RegisterInfo) {
-    errs() << "Failed to initialise RegisterInfo.\n";
-    return EXIT_FAILURE;
-  }
-
-  std::unique_ptr<const MCAsmInfo> AsmInfo(
-      TheTarget->createMCAsmInfo(*RegisterInfo, TripleName));
-  if (!AsmInfo) {
-    errs() << "Failed to initialise AsmInfo.\n";
-    return EXIT_FAILURE;
-  }
-
-  std::string MCPU = "";
-  std::unique_ptr<MCSubtargetInfo> SubtargetInfo(
-      TheTarget->createMCSubtargetInfo(TripleName, MCPU, Features.getString()));
-  if (!SubtargetInfo) {
-    errs() << "Failed to initialise SubtargetInfo.\n";
-    return EXIT_FAILURE;
-  }
-
-  std::unique_ptr<const MCInstrInfo> MII(TheTarget->createMCInstrInfo());
-  if (!MII) {
-    errs() << "Failed to initialise MII.\n";
-    return EXIT_FAILURE;
-  }
-
-  MCObjectFileInfo MOFI;
-  MCContext Context(AsmInfo.get(), RegisterInfo.get(), &MOFI);
-
-  std::unique_ptr<const MCDisassembler> Disassembler(
-      TheTarget->createMCDisassembler(*SubtargetInfo, Context));
-
-  if (!Disassembler) {
-    errs() << "No disassembler available for target.";
-    return EXIT_FAILURE;
-  }
-
-  std::unique_ptr<const MCInstrAnalysis> MIA(
-      TheTarget->createMCInstrAnalysis(MII.get()));
-
-  std::unique_ptr<MCInstPrinter> Printer(
-      TheTarget->createMCInstPrinter(TheTriple, AsmInfo->getAssemblerDialect(),
-                                     *AsmInfo, *MII, *RegisterInfo));
-
-  if (ArgDumpSymbols)
-    printSymbols(Object);
-
-  for (const SectionRef &Section : Object->sections()) {
-    outs() << "Section [" << format_hex_no_prefix(Section.getAddress(), 2)
-           << "] = ";
-    StringRef SectionName;
-
-    if (Section.getName(SectionName))
-      outs() << "UNKNOWN.\n";
-    else
-      outs() << SectionName << "\n";
-
-    StringRef SectionContents;
-    if (Section.getContents(SectionContents)) {
-      errs() << "Failed to retrieve section contents.\n";
-      return EXIT_FAILURE;
-    }
-
-    MCInst Instruction;
-    uint64_t InstructionSize;
-
-    ArrayRef<uint8_t> SectionBytes((const uint8_t *)SectionContents.data(),
-                                   Section.getSize());
-
-    for (uint64_t Byte = 0; Byte < Section.getSize();) {
-      bool BadInstruction = false;
-
-      // Disassemble the instruction.
-      if (Disassembler->getInstruction(
-              Instruction, InstructionSize, SectionBytes.drop_front(Byte), 0,
-              nulls(), outs()) != MCDisassembler::Success) {
-        BadInstruction = true;
-      }
-
-      Byte += InstructionSize;
-
-      if (BadInstruction)
-        continue;
-
-      // Skip instructions that do not affect the control flow.
-      const auto &InstrDesc = MII->get(Instruction.getOpcode());
-      if (!InstrDesc.mayAffectControlFlow(Instruction, *RegisterInfo))
-        continue;
-
-      // Skip instructions that do not operate on register operands.
-      bool UsesRegisterOperand = false;
-      for (const auto &Operand : Instruction) {
-        if (Operand.isReg())
-          UsesRegisterOperand = true;
-      }
-
-      if (!UsesRegisterOperand)
-        continue;
-
-      // Print the instruction address.
-      outs() << "    "
-             << format_hex(Section.getAddress() + Byte - InstructionSize, 2)
-             << ": ";
-
-      // Print the instruction bytes.
-      for (uint64_t i = 0; i < InstructionSize; ++i) {
-        outs() << format_hex_no_prefix(SectionBytes[Byte - InstructionSize + i],
-                                       2)
-               << " ";
-      }
-
-      // Print the instruction.
-      outs() << " | " << MII->getName(Instruction.getOpcode()) << " ";
-      Instruction.dump_pretty(outs(), Printer.get());
-
-      outs() << "\n";
-    }
-  }
+  FileVerifier Verifier = ExitOnErr(FileVerifier::Create(InputFilename));
+  ExitOnErr(Verifier.printIndirectCFInstructions());
 
   return EXIT_SUCCESS;
 }

tools/llvm-cfi-verify/unittests/CMakeLists.txt

+set(LLVM_LINK_COMPONENTS
+  AllTargetsAsmPrinters
+  AllTargetsAsmParsers
+  AllTargetsDescs
+  AllTargetsDisassemblers
+  AllTargetsInfos
+  MC
+  Object
+  MCParser
+  Object
+  Support
+  )
+
+
+
+add_llvm_unittest(CFIVerifyTests
+  FileVerifier.cpp ../FileVerifier.cpp)

tools/llvm-cfi-verify/unittests/FileVerifier.cpp

+//===- llvm/tools/llvm-cfi-verify/unittests/FileVerifier.cpp --------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "../FileVerifier.h"
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+#include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDisassembler/MCDisassembler.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstPrinter.h"
+#include "llvm/MC/MCInstrAnalysis.h"
+#include "llvm/MC/MCInstrDesc.h"
+#include "llvm/MC/MCInstrInfo.h"
+#include "llvm/MC/MCObjectFileInfo.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/Object/Binary.h"
+#include "llvm/Object/COFF.h"
+#include "llvm/Object/ELFObjectFile.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <cstdlib>
+
+using Instr = ::llvm::cfi_verify::FileVerifier::Instr;
+using ::testing::Eq;
+using ::testing::Field;
+
+namespace llvm {
+namespace cfi_verify {
+namespace {
+class ELFx86TestFileVerifier : public FileVerifier {
+public:
+  ELFx86TestFileVerifier()
+      : FileVerifier(Triple("x86_64--"), SubtargetFeatures()) {}
+
+  // Expose this method publicly for testing.
+  void parseSectionContents(ArrayRef<uint8_t> SectionBytes,
+                            uint64_t SectionAddress, StringRef SectionName) {
+    FileVerifier::parseSectionContents(SectionBytes, SectionAddress,
+                                       SectionName);
+  }
+
+  Error initialiseDisassemblyMembers() {
+    return FileVerifier::initialiseDisassemblyMembers();
+  }
+};
+
+class BasicFileVerifierTest : public ::testing::Test {
+protected:
+  virtual void SetUp() {
+    if (Verifier.initialiseDisassemblyMembers()) {
+      exit(EXIT_FAILURE);
+    }
+  }
+
+  ELFx86TestFileVerifier Verifier;
+};
+
+TEST_F(BasicFileVerifierTest, BasicDisassemblyTraversalTest) {
+  Verifier.parseSectionContents(
+      {
+          0x90,                   // 0: nop
+          0xb0, 0x00,             // 1: mov $0x0, %al
+          0x48, 0x89, 0xe5,       // 3: mov %rsp, %rbp
+          0x48, 0x83, 0xec, 0x18, // 6: sub $0x18, %rsp
+          0x48, 0xbe, 0xc4, 0x07, 0x40,
+          0x00, 0x00, 0x00, 0x00, 0x00, // 10: movabs $0x4007c4, %rsi
+          0x2f,                         // 20: (bad)
+          0x41, 0x0e,                   // 21: rex.B (bad)
+          0x62, 0x72, 0x65, 0x61, 0x6b, // 23: (bad) {%k1}
+      },
+      0xDEADBEEF, "Test");
+
+  EXPECT_EQ(nullptr, Verifier.getInstruction(0x0));
+  EXPECT_EQ(nullptr, Verifier.getInstruction(0x1000));
+
+  // 0xDEADBEEF: nop
+  const auto *InstrMeta = Verifier.getInstruction(0xDEADBEEF);
+  EXPECT_NE(nullptr, InstrMeta);
+  EXPECT_EQ(0xDEADBEEF, InstrMeta->VMAddress);
+  EXPECT_EQ(1, InstrMeta->InstructionSize);
+  EXPECT_EQ("Test", InstrMeta->SectionName);
+  EXPECT_FALSE(InstrMeta->Bad);
+
+  const auto *NextInstrMeta = Verifier.getNextInstructionSequential(*InstrMeta);
+  EXPECT_EQ(nullptr, Verifier.getPrevInstructionSequential(*InstrMeta));
+  const auto *PrevInstrMeta = InstrMeta;
+
+  // 0xDEADBEEF + 1: mov $0x0, %al
+  InstrMeta = Verifier.getInstruction(0xDEADBEEF + 1);
+  EXPECT_NE(nullptr, InstrMeta);
+  EXPECT_EQ(NextInstrMeta, InstrMeta);
+  EXPECT_EQ(0xDEADBEEF + 1, InstrMeta->VMAddress);
+  EXPECT_EQ(2, InstrMeta->InstructionSize);
+  EXPECT_EQ("Test", InstrMeta->SectionName);
+  EXPECT_FALSE(InstrMeta->Bad);
+
+  NextInstrMeta = Verifier.getNextInstructionSequential(*InstrMeta);
+  EXPECT_EQ(PrevInstrMeta, Verifier.getPrevInstructionSequential(*InstrMeta));
+  PrevInstrMeta = InstrMeta;
+
+  // 0xDEADBEEF + 3: mov %rsp, %rbp
+  InstrMeta = Verifier.getInstruction(0xDEADBEEF + 3);
+  EXPECT_NE(nullptr, InstrMeta);
+  EXPECT_EQ(NextInstrMeta, InstrMeta);
+  EXPECT_EQ(0xDEADBEEF + 3, InstrMeta->VMAddress);
+  EXPECT_EQ(3, InstrMeta->InstructionSize);
+  EXPECT_EQ("Test", InstrMeta->SectionName);
+  EXPECT_FALSE(InstrMeta->Bad);
+
+  NextInstrMeta = Verifier.getNextInstructionSequential(*InstrMeta);
+  EXPECT_EQ(PrevInstrMeta, Verifier.getPrevInstructionSequential(*InstrMeta));
+  PrevInstrMeta = InstrMeta;
+
+  // 0xDEADBEEF + 6: sub $0x18, %rsp
+  InstrMeta = Verifier.getInstruction(0xDEADBEEF + 6);
+  EXPECT_NE(nullptr, InstrMeta);
+  EXPECT_EQ(NextInstrMeta, InstrMeta);
+  EXPECT_EQ(0xDEADBEEF + 6, InstrMeta->VMAddress);
+  EXPECT_EQ(4, InstrMeta->InstructionSize);
+  EXPECT_EQ("Test", InstrMeta->SectionName);
+  EXPECT_FALSE(InstrMeta->Bad);
+
+  NextInstrMeta = Verifier.getNextInstructionSequential(*InstrMeta);
+  EXPECT_EQ(PrevInstrMeta, Verifier.getPrevInstructionSequential(*InstrMeta));
+  PrevInstrMeta = InstrMeta;
+
+  // 0xDEADBEEF + 10: movabs $0x4007c4, %rsi
+  InstrMeta = Verifier.getInstruction(0xDEADBEEF + 10);
+  EXPECT_NE(nullptr, InstrMeta);
+  EXPECT_EQ(NextInstrMeta, InstrMeta);
+  EXPECT_EQ(0xDEADBEEF + 10, InstrMeta->VMAddress);
+  EXPECT_EQ(10, InstrMeta->InstructionSize);
+  EXPECT_EQ("Test", InstrMeta->SectionName);
+  EXPECT_FALSE(InstrMeta->Bad);
+
+  EXPECT_EQ(nullptr, Verifier.getNextInstructionSequential(*InstrMeta));
+  EXPECT_EQ(PrevInstrMeta, Verifier.getPrevInstructionSequential(*InstrMeta));
+  PrevInstrMeta = InstrMeta;
+
+  // 0xDEADBEEF + 20: (bad)
+  InstrMeta = Verifier.getInstruction(0xDEADBEEF + 20);
+  EXPECT_NE(nullptr, InstrMeta);
+  EXPECT_EQ(0xDEADBEEF + 20, InstrMeta->VMAddress);
+  EXPECT_EQ(1, InstrMeta->InstructionSize);
+  EXPECT_EQ("Test", InstrMeta->SectionName);
+  EXPECT_TRUE(InstrMeta->Bad);
+
+  EXPECT_EQ(nullptr, Verifier.getNextInstructionSequential(*InstrMeta));
+  EXPECT_EQ(PrevInstrMeta, Verifier.getPrevInstructionSequential(*InstrMeta));
+
+  // 0xDEADBEEF + 21: rex.B (bad)
+  InstrMeta = Verifier.getInstruction(0xDEADBEEF + 21);
+  EXPECT_NE(nullptr, InstrMeta);
+  EXPECT_EQ(0xDEADBEEF + 21, InstrMeta->VMAddress);
+  EXPECT_EQ(2, InstrMeta->InstructionSize);
+  EXPECT_EQ("Test", InstrMeta->SectionName);
+  EXPECT_TRUE(InstrMeta->Bad);
+
+  EXPECT_EQ(nullptr, Verifier.getNextInstructionSequential(*InstrMeta));
+  EXPECT_EQ(nullptr, Verifier.getPrevInstructionSequential(*InstrMeta));
+
+  // 0xDEADBEEF + 6: (bad) {%k1}
+  InstrMeta = Verifier.getInstruction(0xDEADBEEF + 23);
+  EXPECT_NE(nullptr, InstrMeta);
+  EXPECT_EQ(0xDEADBEEF + 23, InstrMeta->VMAddress);
+  EXPECT_EQ(5, InstrMeta->InstructionSize);
+  EXPECT_EQ("Test", InstrMeta->SectionName);
+  EXPECT_TRUE(InstrMeta->Bad);
+
+  EXPECT_EQ(nullptr, Verifier.getNextInstructionSequential(*InstrMeta));
+  EXPECT_EQ(nullptr, Verifier.getPrevInstructionSequential(*InstrMeta));
+}
+
+TEST_F(BasicFileVerifierTest, PrevAndNextFromBadInst) {
+  Verifier.parseSectionContents(
+      {
+          0x90, // 0: nop
+          0x2f, // 1: (bad)
+          0x90  // 2: nop
+      },
+      0xDEADBEEF, "Test");
+  const auto &BadInstrMeta = Verifier.getInstructionOrDie(0xDEADBEEF + 1);
+  const auto *GoodInstrMeta =
+      Verifier.getPrevInstructionSequential(BadInstrMeta);
+  EXPECT_NE(nullptr, GoodInstrMeta);
+  EXPECT_EQ(0xDEADBEEF, GoodInstrMeta->VMAddress);
+  EXPECT_EQ(1, GoodInstrMeta->InstructionSize);
+
+  GoodInstrMeta = Verifier.getNextInstructionSequential(BadInstrMeta);
+  EXPECT_NE(nullptr, GoodInstrMeta);
+  EXPECT_EQ(0xDEADBEEF + 2, GoodInstrMeta->VMAddress);
+  EXPECT_EQ(1, GoodInstrMeta->InstructionSize);
+}
+
+TEST_F(BasicFileVerifierTest, UndefinedInstructionTest) {
+  Verifier.parseSectionContents(
+      {
+          0x90,                   // 0: nop
+          0xb0, 0x00,             // 1: mov $0x0, %al
+          0x48, 0x89, 0xe5,       // 3: mov %rsp, %rbp
+          0x48, 0x83, 0xec, 0x18, // 6: sub $0x18, %rsp
+          0x48, 0xbe, 0xc4, 0x07, 0x40,
+          0x00, 0x00, 0x00, 0x00, 0x00, // 10: movabs $0x4007c4, %rsi
+          0x2f,                         // 20: (bad)
+          0x41, 0x0e,                   // 21: rex.B (bad)
+          0x62, 0x72, 0x65, 0x61, 0x6b, // 23: (bad) {%k1}
+          0x0f, 0x0b                    // 28: ud2
+      },
+      0xDEADBEEF, "Test");
+
+  EXPECT_FALSE(Verifier.isUndefinedInstruction(
+      Verifier.getInstructionOrDie(0xDEADBEEF)));
+  EXPECT_FALSE(Verifier.isUndefinedInstruction(
+      Verifier.getInstructionOrDie(0xDEADBEEF + 3)));
+  EXPECT_FALSE(Verifier.isUndefinedInstruction(
+      Verifier.getInstructionOrDie(0xDEADBEEF + 6)));
+  EXPECT_FALSE(Verifier.isUndefinedInstruction(
+      Verifier.getInstructionOrDie(0xDEADBEEF + 10)));
+  EXPECT_FALSE(Verifier.isUndefinedInstruction(
+      Verifier.getInstructionOrDie(0xDEADBEEF + 20)));
+  EXPECT_FALSE(Verifier.isUndefinedInstruction(
+      Verifier.getInstructionOrDie(0xDEADBEEF + 21)));
+  EXPECT_FALSE(Verifier.isUndefinedInstruction(
+      Verifier.getInstructionOrDie(0xDEADBEEF + 23)));
+  EXPECT_TRUE(Verifier.isUndefinedInstruction(
+      Verifier.getInstructionOrDie(0xDEADBEEF + 28)));
+}
+
+TEST_F(BasicFileVerifierTest, FallThroughTest) {
+  Verifier.parseSectionContents(
+      {
+          0x90,                         // 0: nop
+          0xb0, 0x00,                   // 1: mov $0x0, %al
+          0x2f,                         // 3: (bad)
+          0x0f, 0x0b,                   // 4: ud2
+          0xff, 0x20,                   // 6: jmpq *(%rax)
+          0xeb, 0x00,                   // 8: jmp +0
+          0xe8, 0x45, 0xfe, 0xff, 0xff, // 10: callq [some loc]
+          0xff, 0x10,                   // 15: callq *(rax)
+          0x75, 0x00,                   // 17: jne +0
+          0xc3,                         // 19: retq
+      },
+      0xDEADBEEF, "Test");
+
+  EXPECT_TRUE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF)));
+  EXPECT_TRUE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF + 1)));
+  EXPECT_FALSE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF + 3)));
+  EXPECT_FALSE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF + 4)));
+  EXPECT_FALSE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF + 6)));
+  EXPECT_FALSE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF + 8)));
+  EXPECT_FALSE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF + 10)));
+  EXPECT_FALSE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF + 15)));
+  EXPECT_TRUE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF + 17)));
+  EXPECT_FALSE(
+      Verifier.canFallThrough(Verifier.getInstructionOrDie(0xDEADBEEF + 19)));
+}
+
+TEST_F(BasicFileVerifierTest, DefiniteNextInstructionTest) {
+  Verifier.parseSectionContents(
+      {
+          0x90,                         // 0: nop
+          0xb0, 0x00,                   // 1: mov $0x0, %al
+          0x2f,                         // 3: (bad)
+          0x0f, 0x0b,                   // 4: ud2
+          0xff, 0x20,                   // 6: jmpq *(%rax)
+          0xeb, 0x00,                   // 8: jmp 10 [+0]
+          0xeb, 0x05,                   // 10: jmp 17 [+5]
+          0xe8, 0x00, 0x00, 0x00, 0x00, // 12: callq 17 [+0]
+          0xe8, 0x78, 0x56, 0x34, 0x12, // 17: callq 0x1234569f [+0x12345678]
+          0xe8, 0x04, 0x00, 0x00, 0x00, // 22: callq 31 [+4]
+          0xff, 0x10,                   // 27: callq *(rax)
+          0x75, 0x00,                   // 29: jne 31 [+0]
+          0x75, 0xe0,                   // 31: jne 1 [-32]
+          0xc3,                         // 33: retq
+          0xeb, 0xdd,                   // 34: jmp 1 [-35]
+          0xeb, 0xdd,                   // 36: jmp 3 [-35]
+          0xeb, 0xdc,                   // 38: jmp 4 [-36]
+      },
+      0xDEADBEEF, "Test");
+
+  const auto *Current = Verifier.getInstruction(0xDEADBEEF);
+  const auto *Next = Verifier.getDefiniteNextInstruction(*Current);
+  EXPECT_NE(nullptr, Next);
+  EXPECT_EQ(0xDEADBEEF + 1, Next->VMAddress);
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 1);
+  EXPECT_EQ(nullptr, Verifier.getDefiniteNextInstruction(*Current));
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 3);
+  EXPECT_EQ(nullptr, Verifier.getDefiniteNextInstruction(*Current));
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 4);
+  EXPECT_EQ(nullptr, Verifier.getDefiniteNextInstruction(*Current));
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 6);
+  EXPECT_EQ(nullptr, Verifier.getDefiniteNextInstruction(*Current));
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 8);
+  Next = Verifier.getDefiniteNextInstruction(*Current);
+  EXPECT_NE(nullptr, Next);
+  EXPECT_EQ(0xDEADBEEF + 10, Next->VMAddress);
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 10);
+  Next = Verifier.getDefiniteNextInstruction(*Current);
+  EXPECT_NE(nullptr, Next);
+  EXPECT_EQ(0xDEADBEEF + 17, Next->VMAddress);
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 12);
+  Next = Verifier.getDefiniteNextInstruction(*Current);
+  EXPECT_NE(nullptr, Next);
+  EXPECT_EQ(0xDEADBEEF + 17, Next->VMAddress);
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 17);
+  // Note, definite next instruction address is out of range and should fail.
+  EXPECT_EQ(nullptr, Verifier.getDefiniteNextInstruction(*Current));
+  Next = Verifier.getDefiniteNextInstruction(*Current);
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 22);
+  Next = Verifier.getDefiniteNextInstruction(*Current);
+  EXPECT_NE(nullptr, Next);
+  EXPECT_EQ(0xDEADBEEF + 31, Next->VMAddress);
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 27);
+  EXPECT_EQ(nullptr, Verifier.getDefiniteNextInstruction(*Current));
+  Current = Verifier.getInstruction(0xDEADBEEF + 29);
+  EXPECT_EQ(nullptr, Verifier.getDefiniteNextInstruction(*Current));
+  Current = Verifier.getInstruction(0xDEADBEEF + 31);
+  EXPECT_EQ(nullptr, Verifier.getDefiniteNextInstruction(*Current));
+  Current = Verifier.getInstruction(0xDEADBEEF + 33);
+  EXPECT_EQ(nullptr, Verifier.getDefiniteNextInstruction(*Current));
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 34);
+  Next = Verifier.getDefiniteNextInstruction(*Current);
+  EXPECT_NE(nullptr, Next);
+  EXPECT_EQ(0xDEADBEEF + 1, Next->VMAddress);
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 36);
+  Next = Verifier.getDefiniteNextInstruction(*Current);
+  EXPECT_NE(nullptr, Next);
+  EXPECT_EQ(0xDEADBEEF + 3, Next->VMAddress);
+
+  Current = Verifier.getInstruction(0xDEADBEEF + 38);
+  Next = Verifier.getDefiniteNextInstruction(*Current);
+  EXPECT_NE(nullptr, Next);
+  EXPECT_EQ(0xDEADBEEF + 4, Next->VMAddress);
+}
+
+TEST_F(BasicFileVerifierTest, ControlFlowXRefsTest) {
+  Verifier.parseSectionContents(
+      {
+          0x90,                         // 0: nop
+          0xb0, 0x00,                   // 1: mov $0x0, %al
+          0x2f,                         // 3: (bad)
+          0x0f, 0x0b,                   // 4: ud2
+          0xff, 0x20,                   // 6: jmpq *(%rax)
+          0xeb, 0x00,                   // 8: jmp 10 [+0]
+          0xeb, 0x05,                   // 10: jmp 17 [+5]
+          0xe8, 0x00, 0x00, 0x00, 0x00, // 12: callq 17 [+0]
+          0xe8, 0x78, 0x56, 0x34, 0x12, // 17: callq 0x1234569f [+0x12345678]
+          0xe8, 0x04, 0x00, 0x00, 0x00, // 22: callq 31 [+4]
+          0xff, 0x10,                   // 27: callq *(rax)
+          0x75, 0x00,                   // 29: jne 31 [+0]
+          0x75, 0xe0,                   // 31: jne 1 [-32]
+          0xc3,                         // 33: retq
+          0xeb, 0xdd,                   // 34: jmp 1 [-35]
+          0xeb, 0xdd,                   // 36: jmp 3 [-35]
+          0xeb, 0xdc,                   // 38: jmp 4 [-36]
+      },
+      0xDEADBEEF, "Test");
+  const auto *InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF);
+  std::set<const Instr *> XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_TRUE(XRefs.empty());
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 1);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_THAT(XRefs, UnorderedElementsAre(
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF)),
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 31)),
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 34))));
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 3);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_THAT(XRefs, UnorderedElementsAre(
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 1)),
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 36))));
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 4);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_THAT(XRefs, UnorderedElementsAre(
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 38))));
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 6);
+  EXPECT_TRUE(Verifier.getControlFlowXRefs(*InstrMetaPtr).empty());
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 8);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_TRUE(Verifier.getControlFlowXRefs(*InstrMetaPtr).empty());
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 10);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_THAT(XRefs, UnorderedElementsAre(
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 8))));
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 12);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_TRUE(Verifier.getControlFlowXRefs(*InstrMetaPtr).empty());
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 17);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_THAT(XRefs, UnorderedElementsAre(
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 10)),
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 12))));
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 22);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_TRUE(Verifier.getControlFlowXRefs(*InstrMetaPtr).empty());
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 27);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_TRUE(Verifier.getControlFlowXRefs(*InstrMetaPtr).empty());
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 29);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_TRUE(Verifier.getControlFlowXRefs(*InstrMetaPtr).empty());
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 31);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_THAT(XRefs, UnorderedElementsAre(
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 22)),
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 29))));
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 33);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_THAT(XRefs, UnorderedElementsAre(
+                         Field(&Instr::VMAddress, Eq(0xDEADBEEF + 31))));
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 34);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_TRUE(Verifier.getControlFlowXRefs(*InstrMetaPtr).empty());
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 36);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_TRUE(Verifier.getControlFlowXRefs(*InstrMetaPtr).empty());
+
+  InstrMetaPtr = &Verifier.getInstructionOrDie(0xDEADBEEF + 38);
+  XRefs = Verifier.getControlFlowXRefs(*InstrMetaPtr);
+  EXPECT_TRUE(Verifier.getControlFlowXRefs(*InstrMetaPtr).empty());
+}
+
+
+} // anonymous namespace
+} // end namespace cfi_verify
+} // end namespace llvm
+
+int main(int argc, char **argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  llvm::cl::ParseCommandLineOptions(argc, argv);
+
+  llvm::InitializeAllTargetInfos();
+  llvm::InitializeAllTargetMCs();
+  llvm::InitializeAllAsmParsers();
+  llvm::InitializeAllDisassemblers();
+
+  return RUN_ALL_TESTS();
+}

unittests/CMakeLists.txt

 add_subdirectory(BinaryFormat)
 add_subdirectory(ObjectYAML)
 add_subdirectory(Option)
 add_subdirectory(ProfileData)
 add_subdirectory(Support)
 add_subdirectory(Target)
 add_subdirectory(Transforms)
 add_subdirectory(XRay)
+add_subdirectory(../tools/llvm-cfi-verify/unittests ../tools/llvm-cfi-verify/unittests)