Classify llvm-cfi-verify.

Summary: Move llvm-cfi-verify into a class in preparation for CFI analysis to come.

Reviewers: vlad.tsyrklevich

Reviewed By: vlad.tsyrklevich

Subscribers: mgorny, llvm-commits, pcc, kcc

Differential Revision: https://reviews.llvm.org/D38379

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315363 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-cfi-verify/CMakeLists.txt

@@ -13,4 +13,5 @@ set(LLVM_LINK_COMPONENTS
 
 add_llvm_tool(llvm-cfi-verify
   llvm-cfi-verify.cpp
+  FileAnalysis.cpp
   )

tools/llvm-cfi-verify/FileAnalysis.cpp

@@ -0,0 +1,274 @@
+//===- FileAnalysis.cpp -----------------------------------------*- C++ -*-===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "FileAnalysis.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::FileAnalysis::Instr;
+
+namespace llvm {
+namespace cfi_verify {
+
+Expected<FileAnalysis> FileAnalysis::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());
+  FileAnalysis Analysis(std::move(Binary));
+
+  Analysis.Object = dyn_cast<object::ObjectFile>(Analysis.Binary.getBinary());
+  if (!Analysis.Object)
+    return make_error<UnsupportedDisassembly>();
+
+  Analysis.ObjectTriple = Analysis.Object->makeTriple();
+  Analysis.Features = Analysis.Object->getFeatures();
+
+  // Init the rest of the object.
+  if (auto InitResponse = Analysis.initialiseDisassemblyMembers())
+    return std::move(InitResponse);
+
+  if (auto SectionParseResponse = Analysis.parseCodeSections())
+    return std::move(SectionParseResponse);
+
+  return std::move(Analysis);
+}
+
+FileAnalysis::FileAnalysis(object::OwningBinary<object::Binary> Binary)
+    : Binary(std::move(Binary)) {}
+
+FileAnalysis::FileAnalysis(const Triple &ObjectTriple,
+                           const SubtargetFeatures &Features)
+    : ObjectTriple(ObjectTriple), Features(Features) {}
+
+const Instr *
+FileAnalysis::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.Valid)
+    return nullptr;
+
+  return &KV->second;
+}
+
+const Instr *
+FileAnalysis::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.Valid)
+    return nullptr;
+
+  return &KV->second;
+}
+
+bool FileAnalysis::usesRegisterOperand(const Instr& InstrMeta) const {
+  for (const auto &Operand : InstrMeta.Instruction) {
+    if (Operand.isReg())
+      return true;
+  }
+  return false;
+}
+
+const Instr *FileAnalysis::getInstruction(uint64_t Address) const {
+  const auto &InstrKV = Instructions.find(Address);
+  if (InstrKV == Instructions.end())
+    return nullptr;
+
+  return &InstrKV->second;
+}
+
+const Instr &FileAnalysis::getInstructionOrDie(uint64_t Address) const {
+  const auto &InstrKV = Instructions.find(Address);
+  assert(InstrKV != Instructions.end() && "Address doesn't exist.");
+  return InstrKV->second;
+}
+
+const std::set<uint64_t> &FileAnalysis::getIndirectInstructions() const {
+  return IndirectInstructions;
+}
+
+const MCRegisterInfo *FileAnalysis::getRegisterInfo() const {
+  return RegisterInfo.get();
+}
+
+const MCInstrInfo *FileAnalysis::getMCInstrInfo() const { return MII.get(); }
+
+const MCInstrAnalysis *FileAnalysis::getMCInstrAnalysis() const {
+  return MIA.get();
+}
+
+Error FileAnalysis::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 FileAnalysis::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());
+
+    ArrayRef<uint8_t> SectionBytes((const uint8_t *)SectionContents.data(),
+                                   Section.getSize());
+    parseSectionContents(SectionBytes, Section.getAddress());
+  }
+  return Error::success();
+}
+
+void FileAnalysis::parseSectionContents(ArrayRef<uint8_t> SectionBytes,
+                                        uint64_t SectionAddress) {
+  MCInst Instruction;
+  Instr InstrMeta;
+  uint64_t InstructionSize;
+
+  for (uint64_t Byte = 0; Byte < SectionBytes.size();) {
+    bool ValidInstruction =
+        Disassembler->getInstruction(Instruction, InstructionSize,
+                                     SectionBytes.drop_front(Byte), 0, nulls(),
+                                     outs()) == MCDisassembler::Success;
+
+    Byte += InstructionSize;
+
+    uint64_t VMAddress = SectionAddress + Byte - InstructionSize;
+    InstrMeta.Instruction = Instruction;
+    InstrMeta.VMAddress = VMAddress;
+    InstrMeta.InstructionSize = InstructionSize;
+    InstrMeta.Valid = ValidInstruction;
+    addInstruction(InstrMeta);
+
+    if (!ValidInstruction)
+      continue;
+
+    // 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;
+    }
+
+    if (!usesRegisterOperand(InstrMeta))
+      continue;
+
+    IndirectInstructions.insert(VMAddress);
+  }
+}
+
+void FileAnalysis::addInstruction(const Instr &Instruction) {
+  const auto &KV =
+      Instructions.insert(std::make_pair(Instruction.VMAddress, Instruction));
+  assert(
+      KV.second &&
+      "Failed to add instruction, instruction at this address already exists.");
+}
+
+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