//===-- llvm-dwarfdump.cpp - Debug info dumping utility for llvm ----------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This program is a utility that works like "dwarfdump".
//
//===----------------------------------------------------------------------===//

#include "llvm-dwarfdump.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/DebugInfo/DIContext.h"
#include "llvm/DebugInfo/DWARF/DWARFAcceleratorTable.h"
#include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/MC/MCRegisterInfo.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Object/Archive.h"
#include "llvm/Object/MachOUniversal.h"
#include "llvm/Object/ObjectFile.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/FormatVariadic.h"
#include "llvm/Support/InitLLVM.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/Parallel.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/Regex.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/Threading.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Support/WithColor.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/TargetParser/Triple.h"
#include <cstdlib>

using namespace llvm;
using namespace llvm::dwarfdump;
using namespace llvm::object;

namespace {
/// Parser for options that take an optional offest argument.
/// @{
struct OffsetOption {
  uint64_t Val = 0;
  bool HasValue = false;
  bool IsRequested = false;
};
struct BoolOption : public OffsetOption {};
} // namespace

namespace llvm {
namespace cl {
template <>
class parser<OffsetOption> final : public basic_parser<OffsetOption> {
public:
  parser(Option &O) : basic_parser(O) {}

  /// Return true on error.
  bool parse(Option &O, StringRef ArgName, StringRef Arg, OffsetOption &Val) {
    if (Arg == "") {
      Val.Val = 0;
      Val.HasValue = false;
      Val.IsRequested = true;
      return false;
    }
    if (Arg.getAsInteger(0, Val.Val))
      return O.error("'" + Arg + "' value invalid for integer argument");
    Val.HasValue = true;
    Val.IsRequested = true;
    return false;
  }

  enum ValueExpected getValueExpectedFlagDefault() const {
    return ValueOptional;
  }

  StringRef getValueName() const override { return StringRef("offset"); }

  void printOptionDiff(const Option &O, OffsetOption V, OptVal Default,
                       size_t GlobalWidth) const {
    printOptionName(O, GlobalWidth);
    outs() << "[=offset]";
  }
};

template <> class parser<BoolOption> final : public basic_parser<BoolOption> {
public:
  parser(Option &O) : basic_parser(O) {}

  /// Return true on error.
  bool parse(Option &O, StringRef ArgName, StringRef Arg, BoolOption &Val) {
    if (Arg != "")
      return O.error("this is a flag and does not take a value");
    Val.Val = 0;
    Val.HasValue = false;
    Val.IsRequested = true;
    return false;
  }

  enum ValueExpected getValueExpectedFlagDefault() const {
    return ValueOptional;
  }

  StringRef getValueName() const override { return StringRef(); }

  void printOptionDiff(const Option &O, OffsetOption V, OptVal Default,
                       size_t GlobalWidth) const {
    printOptionName(O, GlobalWidth);
  }
};
} // namespace cl
} // namespace llvm

/// @}
/// Command line options.
/// @{

namespace {
using namespace cl;

enum ErrorDetailLevel {
  OnlyDetailsNoSummary,
  NoDetailsOnlySummary,
  NoDetailsOrSummary,
  BothDetailsAndSummary,
  Unspecified
};

OptionCategory DwarfDumpCategory("Specific Options");
static list<std::string>
    InputFilenames(Positional, desc("<input object files or .dSYM bundles>"),
                   cat(DwarfDumpCategory));

cl::OptionCategory SectionCategory("Section-specific Dump Options",
                                   "These control which sections are dumped. "
                                   "Where applicable these parameters take an "
                                   "optional =<offset> argument to dump only "
                                   "the entry at the specified offset.");

static opt<bool> DumpAll("all", desc("Dump all debug info sections"),
                         cat(SectionCategory));
static alias DumpAllAlias("a", desc("Alias for --all"), aliasopt(DumpAll),
                          cl::NotHidden);

// Options for dumping specific sections.
static unsigned DumpType = DIDT_Null;
static std::array<std::optional<uint64_t>, (unsigned)DIDT_ID_Count> DumpOffsets;
#define HANDLE_DWARF_SECTION(ENUM_NAME, ELF_NAME, CMDLINE_NAME, OPTION)        \
  static opt<OPTION> Dump##ENUM_NAME(CMDLINE_NAME,                             \
                                     desc("Dump the " ELF_NAME " section"),    \
                                     cat(SectionCategory));
#include "llvm/BinaryFormat/Dwarf.def"
#undef HANDLE_DWARF_SECTION

// The aliased DumpDebugFrame is created by the Dwarf.def x-macro just above.
static alias DumpDebugFrameAlias("eh-frame", desc("Alias for --debug-frame"),
                                 NotHidden, cat(SectionCategory),
                                 aliasopt(DumpDebugFrame));
static list<std::string>
    ArchFilters("arch",
                desc("Dump debug information for the specified CPU "
                     "architecture only. Architectures may be specified by "
                     "name or by number. This option can be specified "
                     "multiple times, once for each desired architecture."),
                cat(DwarfDumpCategory));
static opt<bool>
    Diff("diff",
         desc("Emit diff-friendly output by omitting offsets and addresses."),
         cat(DwarfDumpCategory));
static list<std::string>
    Find("find",
         desc("Search for the exact match for <name> in the accelerator tables "
              "and print the matching debug information entries. When no "
              "accelerator tables are available, the slower but more complete "
              "-name option can be used instead."),
         value_desc("name"), cat(DwarfDumpCategory));
static alias FindAlias("f", desc("Alias for --find."), aliasopt(Find),
                       cl::NotHidden);
static opt<bool> FindAllApple(
    "find-all-apple",
    desc("Print every debug information entry in the accelerator tables."),
    cat(DwarfDumpCategory));
static opt<bool> IgnoreCase("ignore-case",
                            desc("Ignore case distinctions when using --name."),
                            value_desc("i"), cat(DwarfDumpCategory));
static opt<bool> DumpNonSkeleton(
    "dwo",
    desc("Dump the non skeleton DIE in the .dwo or .dwp file after dumping the "
         "skeleton DIE from the main executable. This allows dumping the .dwo "
         "files with resolved addresses."),
    value_desc("d"), cat(DwarfDumpCategory));

static alias IgnoreCaseAlias("i", desc("Alias for --ignore-case."),
                             aliasopt(IgnoreCase), cl::NotHidden);
static list<std::string> Name(
    "name",
    desc("Find and print all debug info entries whose name (DW_AT_name "
         "attribute) matches the exact text in <pattern>.  When used with the "
         "the -regex option <pattern> is interpreted as a regular expression."),
    value_desc("pattern"), cat(DwarfDumpCategory));
static alias NameAlias("n", desc("Alias for --name"), aliasopt(Name),
                       cl::NotHidden);
static opt<uint64_t>
    Lookup("lookup",
           desc("Lookup <address> in the debug information and print out any "
                "available file, function, block and line table details."),
           value_desc("address"), cat(DwarfDumpCategory));
static opt<std::string>
    OutputFilename("o", cl::init("-"),
                   cl::desc("Redirect output to the specified file."),
                   cl::value_desc("filename"), cat(DwarfDumpCategory));
static alias OutputFilenameAlias("out-file", desc("Alias for -o."),
                                 aliasopt(OutputFilename));
static opt<bool> UseRegex(
    "regex",
    desc("Treat any <pattern> strings as regular "
         "expressions when searching with --name. If --ignore-case is also "
         "specified, the regular expression becomes case-insensitive."),
    cat(DwarfDumpCategory));
static alias RegexAlias("x", desc("Alias for --regex"), aliasopt(UseRegex),
                        cl::NotHidden);
static opt<bool>
    ShowChildren("show-children",
                 desc("Show a debug info entry's children when selectively "
                      "printing entries."),
                 cat(DwarfDumpCategory));
static alias ShowChildrenAlias("c", desc("Alias for --show-children."),
                               aliasopt(ShowChildren), cl::NotHidden);
static opt<bool>
    ShowParents("show-parents",
                desc("Show a debug info entry's parents when selectively "
                     "printing entries."),
                cat(DwarfDumpCategory));
static alias ShowParentsAlias("p", desc("Alias for --show-parents."),
                              aliasopt(ShowParents), cl::NotHidden);
static opt<bool>
    ShowForm("show-form",
             desc("Show DWARF form types after the DWARF attribute types."),
             cat(DwarfDumpCategory));
static alias ShowFormAlias("F", desc("Alias for --show-form."),
                           aliasopt(ShowForm), cat(DwarfDumpCategory),
                           cl::NotHidden);
static opt<unsigned>
    ChildRecurseDepth("recurse-depth",
                      desc("Only recurse to a depth of N when displaying "
                           "children of debug info entries."),
                      cat(DwarfDumpCategory), init(-1U), value_desc("N"));
static alias ChildRecurseDepthAlias("r", desc("Alias for --recurse-depth."),
                                    aliasopt(ChildRecurseDepth), cl::NotHidden);
static opt<unsigned>
    ParentRecurseDepth("parent-recurse-depth",
                       desc("Only recurse to a depth of N when displaying "
                            "parents of debug info entries."),
                       cat(DwarfDumpCategory), init(-1U), value_desc("N"));
static opt<bool>
    SummarizeTypes("summarize-types",
                   desc("Abbreviate the description of type unit entries."),
                   cat(DwarfDumpCategory));
static cl::opt<bool>
    Statistics("statistics",
               cl::desc("Emit JSON-formatted debug info quality metrics."),
               cat(DwarfDumpCategory));
static cl::opt<bool>
    ShowSectionSizes("show-section-sizes",
                     cl::desc("Show the sizes of all debug sections, "
                              "expressed in bytes."),
                     cat(DwarfDumpCategory));
static cl::opt<bool> ManuallyGenerateUnitIndex(
    "manually-generate-unit-index",
    cl::desc("if the input is dwp file, parse .debug_info "
             "section and use it to populate "
             "DW_SECT_INFO contributions in cu-index. "
             "For DWARF5 it also populated TU Index."),
    cl::init(false), cl::Hidden, cl::cat(DwarfDumpCategory));
static cl::opt<bool>
    ShowSources("show-sources",
                cl::desc("Show the sources across all compilation units."),
                cat(DwarfDumpCategory));
static opt<bool> Verify("verify", desc("Verify the DWARF debug info."),
                        cat(DwarfDumpCategory));
static opt<unsigned> VerifyNumThreads(
    "verify-num-threads", init(1),
    desc("Number of threads to use for --verify. Single threaded verification "
         "is the default unless this option is specified. If 0 is specified, "
         "maximum hardware threads will be used. This can cause the "
         "output to be non determinisitic, but can speed up verification and "
         "is useful when running with the summary only or JSON summary modes."),
    cat(DwarfDumpCategory));
static opt<ErrorDetailLevel> ErrorDetails(
    "error-display", init(Unspecified),
    desc("Set the level of detail and summary to display when verifying "
         "(implies --verify)"),
    values(clEnumValN(NoDetailsOrSummary, "quiet",
                      "Only display whether errors occurred."),
           clEnumValN(NoDetailsOnlySummary, "summary",
                      "Display only a summary of the errors found."),
           clEnumValN(OnlyDetailsNoSummary, "details",
                      "Display each error in detail but no summary."),
           clEnumValN(BothDetailsAndSummary, "full",
                      "Display each error as well as a summary. [default]")),
    cat(DwarfDumpCategory));
static opt<std::string> JsonErrSummaryFile(
    "verify-json", init(""),
    desc("Output JSON-formatted error summary to the specified file. "
         "(Implies --verify)"),
    value_desc("filename.json"), cat(DwarfDumpCategory));
static opt<bool> Quiet("quiet", desc("Use with -verify to not emit to STDOUT."),
                       cat(DwarfDumpCategory));
static opt<bool> DumpUUID("uuid", desc("Show the UUID for each architecture."),
                          cat(DwarfDumpCategory));
static alias DumpUUIDAlias("u", desc("Alias for --uuid."), aliasopt(DumpUUID),
                           cl::NotHidden);
static opt<bool> Verbose("verbose",
                         desc("Print more low-level encoding details."),
                         cat(DwarfDumpCategory));
static alias VerboseAlias("v", desc("Alias for --verbose."), aliasopt(Verbose),
                          cat(DwarfDumpCategory), cl::NotHidden);
static cl::extrahelp
    HelpResponse("\nPass @FILE as argument to read options from FILE.\n");
} // namespace
/// @}
//===----------------------------------------------------------------------===//

static void error(Error Err) {
  if (!Err)
    return;
  WithColor::error() << toString(std::move(Err)) << "\n";
  exit(1);
}

static void error(StringRef Prefix, Error Err) {
  if (!Err)
    return;
  WithColor::error() << Prefix << ": " << toString(std::move(Err)) << "\n";
  exit(1);
}

static void error(StringRef Prefix, std::error_code EC) {
  error(Prefix, errorCodeToError(EC));
}

static DIDumpOptions getDumpOpts(DWARFContext &C) {
  DIDumpOptions DumpOpts;
  DumpOpts.DumpType = DumpType;
  DumpOpts.ChildRecurseDepth = ChildRecurseDepth;
  DumpOpts.ParentRecurseDepth = ParentRecurseDepth;
  DumpOpts.ShowAddresses = !Diff;
  DumpOpts.ShowChildren = ShowChildren;
  DumpOpts.ShowParents = ShowParents;
  DumpOpts.ShowForm = ShowForm;
  DumpOpts.SummarizeTypes = SummarizeTypes;
  DumpOpts.Verbose = Verbose;
  DumpOpts.DumpNonSkeleton = DumpNonSkeleton;
  DumpOpts.RecoverableErrorHandler = C.getRecoverableErrorHandler();
  // In -verify mode, print DIEs without children in error messages.
  if (Verify) {
    DumpOpts.Verbose = ErrorDetails != NoDetailsOnlySummary &&
                       ErrorDetails != NoDetailsOrSummary;
    DumpOpts.ShowAggregateErrors = ErrorDetails != OnlyDetailsNoSummary &&
                                   ErrorDetails != NoDetailsOnlySummary;
    DumpOpts.JsonErrSummaryFile = JsonErrSummaryFile;
    return DumpOpts.noImplicitRecursion();
  }
  return DumpOpts;
}

static uint32_t getCPUType(MachOObjectFile &MachO) {
  if (MachO.is64Bit())
    return MachO.getHeader64().cputype;
  else
    return MachO.getHeader().cputype;
}

/// Return true if the object file has not been filtered by an --arch option.
static bool filterArch(ObjectFile &Obj) {
  if (ArchFilters.empty())
    return true;

  if (auto *MachO = dyn_cast<MachOObjectFile>(&Obj)) {
    for (const StringRef Arch : ArchFilters) {
      // Match architecture number.
      unsigned Value;
      if (!Arch.getAsInteger(0, Value))
        if (Value == getCPUType(*MachO))
          return true;

      // Match as name.
      if (MachO->getArchTriple().getArchName() == Triple(Arch).getArchName())
        return true;
    }
  }
  return false;
}

using HandlerFn = std::function<bool(ObjectFile &, DWARFContext &DICtx,
                                     const Twine &, raw_ostream &)>;

/// Print only DIEs that have a certain name.
static bool filterByName(
    const StringSet<> &Names, DWARFDie Die, StringRef NameRef, raw_ostream &OS,
    std::function<StringRef(uint64_t RegNum, bool IsEH)> GetNameForDWARFReg) {
  DIDumpOptions DumpOpts = getDumpOpts(Die.getDwarfUnit()->getContext());
  DumpOpts.GetNameForDWARFReg = GetNameForDWARFReg;
  std::string Name =
      (IgnoreCase && !UseRegex) ? NameRef.lower() : NameRef.str();
  if (UseRegex) {
    // Match regular expression.
    for (auto Pattern : Names.keys()) {
      Regex RE(Pattern, IgnoreCase ? Regex::IgnoreCase : Regex::NoFlags);
      std::string Error;
      if (!RE.isValid(Error)) {
        errs() << "error in regular expression: " << Error << "\n";
        exit(1);
      }
      if (RE.match(Name)) {
        Die.dump(OS, 0, DumpOpts);
        return true;
      }
    }
  } else if (Names.count(Name)) {
    // Match full text.
    Die.dump(OS, 0, DumpOpts);
    return true;
  }
  return false;
}

/// Print only DIEs that have a certain name.
static void filterByName(
    const StringSet<> &Names, DWARFContext::unit_iterator_range CUs,
    raw_ostream &OS,
    std::function<StringRef(uint64_t RegNum, bool IsEH)> GetNameForDWARFReg) {
  auto filterDieNames = [&](DWARFUnit *Unit) {
    for (const auto &Entry : Unit->dies()) {
      DWARFDie Die = {Unit, &Entry};
      if (const char *Name = Die.getName(DINameKind::ShortName))
        if (filterByName(Names, Die, Name, OS, GetNameForDWARFReg))
          continue;
      if (const char *Name = Die.getName(DINameKind::LinkageName))
        filterByName(Names, Die, Name, OS, GetNameForDWARFReg);
    }
  };
  for (const auto &CU : CUs) {
    filterDieNames(CU.get());
    if (DumpNonSkeleton) {
      // If we have split DWARF, then recurse down into the .dwo files as well.
      DWARFDie CUDie = CU->getUnitDIE(false);
      DWARFDie CUNonSkeletonDie = CU->getNonSkeletonUnitDIE(false);
      // If we have a DWO file, we need to search it as well
      if (CUNonSkeletonDie && CUDie != CUNonSkeletonDie)
        filterDieNames(CUNonSkeletonDie.getDwarfUnit());
    }
  }
}

static void getDies(DWARFContext &DICtx, const AppleAcceleratorTable &Accel,
                    StringRef Name, SmallVectorImpl<DWARFDie> &Dies) {
  for (const auto &Entry : Accel.equal_range(Name)) {
    if (std::optional<uint64_t> Off = Entry.getDIESectionOffset()) {
      if (DWARFDie Die = DICtx.getDIEForOffset(*Off))
        Dies.push_back(Die);
    }
  }
}

static DWARFDie toDie(const DWARFDebugNames::Entry &Entry,
                      DWARFContext &DICtx) {
  std::optional<uint64_t> CUOff = Entry.getCUOffset();
  std::optional<uint64_t> Off = Entry.getDIEUnitOffset();
  if (!CUOff || !Off)
    return DWARFDie();

  DWARFCompileUnit *CU = DICtx.getCompileUnitForOffset(*CUOff);
  if (!CU)
    return DWARFDie();

  if (std::optional<uint64_t> DWOId = CU->getDWOId()) {
    // This is a skeleton unit. Look up the DIE in the DWO unit.
    CU = DICtx.getDWOCompileUnitForHash(*DWOId);
    if (!CU)
      return DWARFDie();
  }

  return CU->getDIEForOffset(CU->getOffset() + *Off);
}

static void getDies(DWARFContext &DICtx, const DWARFDebugNames &Accel,
                    StringRef Name, SmallVectorImpl<DWARFDie> &Dies) {
  for (const auto &Entry : Accel.equal_range(Name)) {
    if (DWARFDie Die = toDie(Entry, DICtx))
      Dies.push_back(Die);
  }
}

/// Print only DIEs that have a certain name.
static void filterByAccelName(
    ArrayRef<std::string> Names, DWARFContext &DICtx, raw_ostream &OS,
    std::function<StringRef(uint64_t RegNum, bool IsEH)> GetNameForDWARFReg) {
  SmallVector<DWARFDie, 4> Dies;
  for (const auto &Name : Names) {
    getDies(DICtx, DICtx.getAppleNames(), Name, Dies);
    getDies(DICtx, DICtx.getAppleTypes(), Name, Dies);
    getDies(DICtx, DICtx.getAppleNamespaces(), Name, Dies);
    getDies(DICtx, DICtx.getDebugNames(), Name, Dies);
  }
  llvm::sort(Dies);
  Dies.erase(llvm::unique(Dies), Dies.end());

  DIDumpOptions DumpOpts = getDumpOpts(DICtx);
  DumpOpts.GetNameForDWARFReg = GetNameForDWARFReg;
  for (DWARFDie Die : Dies)
    Die.dump(OS, 0, DumpOpts);
}

/// Print all DIEs in apple accelerator tables
static void findAllApple(
    DWARFContext &DICtx, raw_ostream &OS,
    std::function<StringRef(uint64_t RegNum, bool IsEH)> GetNameForDWARFReg) {
  MapVector<StringRef, llvm::SmallSet<DWARFDie, 2>> NameToDies;

  auto PushDIEs = [&](const AppleAcceleratorTable &Accel) {
    for (const auto &Entry : Accel.entries()) {
      if (std::optional<uint64_t> Off = Entry.BaseEntry.getDIESectionOffset()) {
        std::optional<StringRef> MaybeName = Entry.readName();
        DWARFDie Die = DICtx.getDIEForOffset(*Off);
        if (Die && MaybeName)
          NameToDies[*MaybeName].insert(Die);
      }
    }
  };

  PushDIEs(DICtx.getAppleNames());
  PushDIEs(DICtx.getAppleNamespaces());
  PushDIEs(DICtx.getAppleTypes());

  DIDumpOptions DumpOpts = getDumpOpts(DICtx);
  DumpOpts.GetNameForDWARFReg = GetNameForDWARFReg;
  for (const auto &[Name, Dies] : NameToDies) {
    OS << llvm::formatv("\nApple accelerator entries with name = \"{0}\":\n",
                        Name);
    for (DWARFDie Die : Dies)
      Die.dump(OS, 0, DumpOpts);
  }
}

/// Handle the --lookup option and dump the DIEs and line info for the given
/// address.
/// TODO: specified Address for --lookup option could relate for several
/// different sections(in case not-linked object file). llvm-dwarfdump
/// need to do something with this: extend lookup option with section
/// information or probably display all matched entries, or something else...
static bool lookup(ObjectFile &Obj, DWARFContext &DICtx, uint64_t Address,
                   raw_ostream &OS) {
  auto DIEsForAddr = DICtx.getDIEsForAddress(Lookup, DumpNonSkeleton);

  if (!DIEsForAddr)
    return false;

  DIDumpOptions DumpOpts = getDumpOpts(DICtx);
  DumpOpts.ChildRecurseDepth = 0;
  DIEsForAddr.CompileUnit->dump(OS, DumpOpts);
  if (DIEsForAddr.FunctionDIE) {
    DIEsForAddr.FunctionDIE.dump(OS, 2, DumpOpts);
    if (DIEsForAddr.BlockDIE)
      DIEsForAddr.BlockDIE.dump(OS, 4, DumpOpts);
  }

  // TODO: it is neccessary to set proper SectionIndex here.
  // object::SectionedAddress::UndefSection works for only absolute addresses.
  if (DILineInfo LineInfo =
          DICtx
              .getLineInfoForAddress(
                  {Lookup, object::SectionedAddress::UndefSection})
              .value_or(DILineInfo())) {
    LineInfo.dump(OS);
  }

  return true;
}

// Collect all sources referenced from the given line table, scoped to the given
// CU compilation directory.
static bool collectLineTableSources(const DWARFDebugLine::LineTable &LT,
                                    StringRef CompDir,
                                    std::vector<std::string> &Sources) {
  bool Result = true;
  std::optional<uint64_t> LastIndex = LT.getLastValidFileIndex();
  for (uint64_t I = LT.hasFileAtIndex(0) ? 0 : 1,
                E = LastIndex ? *LastIndex + 1 : 0;
       I < E; ++I) {
    std::string Path;
    Result &= LT.getFileNameByIndex(
        I, CompDir, DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath,
        Path);
    Sources.push_back(std::move(Path));
  }
  return Result;
}

static bool collectObjectSources(ObjectFile &Obj, DWARFContext &DICtx,
                                 const Twine &Filename, raw_ostream &OS) {
  bool Result = true;
  std::vector<std::string> Sources;

  bool HasCompileUnits = false;
  for (const auto &CU : DICtx.compile_units()) {
    HasCompileUnits = true;
    // Extract paths from the line table for this CU. This allows combining the
    // compilation directory with the line information, in case both the include
    // directory and file names in the line table are relative.
    const DWARFDebugLine::LineTable *LT = DICtx.getLineTableForUnit(CU.get());
    StringRef CompDir = CU->getCompilationDir();
    if (LT) {
      Result &= collectLineTableSources(*LT, CompDir, Sources);
    } else {
      // Since there's no line table for this CU, collect the name from the CU
      // itself.
      const char *Name = CU->getUnitDIE().getShortName();
      if (!Name) {
        WithColor::warning()
            << Filename << ": missing name for compilation unit\n";
        continue;
      }
      SmallString<64> AbsName;
      if (sys::path::is_relative(Name, sys::path::Style::posix) &&
          sys::path::is_relative(Name, sys::path::Style::windows))
        AbsName = CompDir;
      sys::path::append(AbsName, Name);
      Sources.push_back(std::string(AbsName));
    }
  }

  if (!HasCompileUnits) {
    // Since there's no compile units available, walk the line tables and
    // extract out any referenced paths.
    DWARFDataExtractor LineData(DICtx.getDWARFObj(),
                                DICtx.getDWARFObj().getLineSection(),
                                DICtx.isLittleEndian(), 0);
    DWARFDebugLine::SectionParser Parser(LineData, DICtx, DICtx.normal_units());
    while (!Parser.done()) {
      const auto RecoverableErrorHandler = [&](Error Err) {
        Result = false;
        WithColor::defaultErrorHandler(std::move(Err));
      };
      void (*UnrecoverableErrorHandler)(Error Err) = error;

      DWARFDebugLine::LineTable LT =
          Parser.parseNext(RecoverableErrorHandler, UnrecoverableErrorHandler);
      Result &= collectLineTableSources(LT, /*CompDir=*/"", Sources);
    }
  }

  // Dedup and order the sources.
  llvm::sort(Sources);
  Sources.erase(llvm::unique(Sources), Sources.end());

  for (StringRef Name : Sources)
    OS << Name << "\n";
  return Result;
}

static std::unique_ptr<MCRegisterInfo>
createRegInfo(const object::ObjectFile &Obj) {
  std::unique_ptr<MCRegisterInfo> MCRegInfo;
  Triple TT;
  TT.setArch(Triple::ArchType(Obj.getArch()));
  TT.setVendor(Triple::UnknownVendor);
  TT.setOS(Triple::UnknownOS);
  std::string TargetLookupError;
  const Target *TheTarget = TargetRegistry::lookupTarget(TT, TargetLookupError);
  if (!TargetLookupError.empty())
    return nullptr;
  MCRegInfo.reset(TheTarget->createMCRegInfo(TT.str()));
  return MCRegInfo;
}

static bool dumpObjectFile(ObjectFile &Obj, DWARFContext &DICtx,
                           const Twine &Filename, raw_ostream &OS) {

  auto MCRegInfo = createRegInfo(Obj);
  if (!MCRegInfo)
    logAllUnhandledErrors(createStringError(inconvertibleErrorCode(),
                                            "Error in creating MCRegInfo"),
                          errs(), Filename.str() + ": ");

  auto GetRegName = [&MCRegInfo](uint64_t DwarfRegNum, bool IsEH) -> StringRef {
    if (!MCRegInfo)
      return {};
    if (std::optional<MCRegister> LLVMRegNum =
            MCRegInfo->getLLVMRegNum(DwarfRegNum, IsEH))
      if (const char *RegName = MCRegInfo->getName(*LLVMRegNum))
        return StringRef(RegName);
    return {};
  };

  // The UUID dump already contains all the same information.
  if (!(DumpType & DIDT_UUID) || DumpType == DIDT_All)
    OS << Filename << ":\tfile format " << Obj.getFileFormatName() << '\n';

  // Handle the --lookup option.
  if (Lookup)
    return lookup(Obj, DICtx, Lookup, OS);

  // Handle the --name option.
  if (!Name.empty()) {
    StringSet<> Names;
    for (const auto &name : Name)
      Names.insert((IgnoreCase && !UseRegex) ? StringRef(name).lower() : name);

    filterByName(Names, DICtx.normal_units(), OS, GetRegName);
    filterByName(Names, DICtx.dwo_units(), OS, GetRegName);
    return true;
  }

  // Handle the --find option and lower it to --debug-info=<offset>.
  if (!Find.empty()) {
    filterByAccelName(Find, DICtx, OS, GetRegName);
    return true;
  }

  // Handle the --find-all-apple option and lower it to --debug-info=<offset>.
  if (FindAllApple) {
    findAllApple(DICtx, OS, GetRegName);
    return true;
  }

  // Dump the complete DWARF structure.
  auto DumpOpts = getDumpOpts(DICtx);
  DumpOpts.GetNameForDWARFReg = GetRegName;
  DICtx.dump(OS, DumpOpts, DumpOffsets);
  return true;
}

static bool verifyObjectFile(ObjectFile &Obj, DWARFContext &DICtx,
                             const Twine &Filename, raw_ostream &OS) {
  // Verify the DWARF and exit with non-zero exit status if verification
  // fails.
  raw_ostream &stream = Quiet ? nulls() : OS;
  stream << "Verifying " << Filename.str() << ":\tfile format "
         << Obj.getFileFormatName() << "\n";
  bool Result = DICtx.verify(stream, getDumpOpts(DICtx));
  if (Result)
    stream << "No errors.\n";
  else
    stream << "Errors detected.\n";
  return Result;
}

static bool handleBuffer(StringRef Filename, MemoryBufferRef Buffer,
                         HandlerFn HandleObj, raw_ostream &OS);

static bool handleArchive(StringRef Filename, Archive &Arch,
                          HandlerFn HandleObj, raw_ostream &OS) {
  bool Result = true;
  Error Err = Error::success();
  for (const auto &Child : Arch.children(Err)) {
    auto BuffOrErr = Child.getMemoryBufferRef();
    error(Filename, BuffOrErr.takeError());
    auto NameOrErr = Child.getName();
    error(Filename, NameOrErr.takeError());
    std::string Name = (Filename + "(" + NameOrErr.get() + ")").str();
    Result &= handleBuffer(Name, BuffOrErr.get(), HandleObj, OS);
  }
  error(Filename, std::move(Err));

  return Result;
}

static bool handleBuffer(StringRef Filename, MemoryBufferRef Buffer,
                         HandlerFn HandleObj, raw_ostream &OS) {
  Expected<std::unique_ptr<Binary>> BinOrErr = object::createBinary(Buffer);
  error(Filename, BinOrErr.takeError());

  bool Result = true;
  auto RecoverableErrorHandler = [&](Error E) {
    Result = false;
    WithColor::defaultErrorHandler(std::move(E));
  };
  if (auto *Obj = dyn_cast<ObjectFile>(BinOrErr->get())) {
    if (filterArch(*Obj)) {
      std::unique_ptr<DWARFContext> DICtx = DWARFContext::create(
          *Obj, DWARFContext::ProcessDebugRelocations::Process, nullptr, "",
          RecoverableErrorHandler, WithColor::defaultWarningHandler,
          /*ThreadSafe=*/true);
      DICtx->setParseCUTUIndexManually(ManuallyGenerateUnitIndex);
      if (!HandleObj(*Obj, *DICtx, Filename, OS))
        Result = false;
    }
  } else if (auto *Fat = dyn_cast<MachOUniversalBinary>(BinOrErr->get()))
    for (auto &ObjForArch : Fat->objects()) {
      std::string ObjName =
          (Filename + "(" + ObjForArch.getArchFlagName() + ")").str();
      if (auto MachOOrErr = ObjForArch.getAsObjectFile()) {
        auto &Obj = **MachOOrErr;
        if (filterArch(Obj)) {
          std::unique_ptr<DWARFContext> DICtx = DWARFContext::create(
              Obj, DWARFContext::ProcessDebugRelocations::Process, nullptr, "",
              RecoverableErrorHandler);
          if (!HandleObj(Obj, *DICtx, ObjName, OS))
            Result = false;
        }
        continue;
      } else
        consumeError(MachOOrErr.takeError());
      if (auto ArchiveOrErr = ObjForArch.getAsArchive()) {
        error(ObjName, ArchiveOrErr.takeError());
        if (!handleArchive(ObjName, *ArchiveOrErr.get(), HandleObj, OS))
          Result = false;
        continue;
      } else
        consumeError(ArchiveOrErr.takeError());
    }
  else if (auto *Arch = dyn_cast<Archive>(BinOrErr->get()))
    Result = handleArchive(Filename, *Arch, HandleObj, OS);
  return Result;
}

static bool handleFile(StringRef Filename, HandlerFn HandleObj,
                       raw_ostream &OS) {
  ErrorOr<std::unique_ptr<MemoryBuffer>> BuffOrErr =
      MemoryBuffer::getFileOrSTDIN(Filename);
  error(Filename, BuffOrErr.getError());
  std::unique_ptr<MemoryBuffer> Buffer = std::move(BuffOrErr.get());
  return handleBuffer(Filename, *Buffer, HandleObj, OS);
}

int main(int argc, char **argv) {
  InitLLVM X(argc, argv);

  // Flush outs() when printing to errs(). This avoids interleaving output
  // between the two.
  errs().tie(&outs());

  llvm::InitializeAllTargetInfos();
  llvm::InitializeAllTargetMCs();

  HideUnrelatedOptions(
      {&DwarfDumpCategory, &SectionCategory, &getColorCategory()});
  cl::ParseCommandLineOptions(
      argc, argv,
      "pretty-print DWARF debug information in object files"
      " and debug info archives.\n");

  // FIXME: Audit interactions between these two options and make them
  //        compatible.
  if (Diff && Verbose) {
    WithColor::error() << "incompatible arguments: specifying both -diff and "
                          "-verbose is currently not supported";
    return 1;
  }
  // -error-detail and -json-summary-file both imply -verify
  if (ErrorDetails != Unspecified || !JsonErrSummaryFile.empty()) {
    Verify = true;
  }

  std::error_code EC;
  ToolOutputFile OutputFile(OutputFilename, EC, sys::fs::OF_TextWithCRLF);
  error("unable to open output file " + OutputFilename, EC);
  // Don't remove output file if we exit with an error.
  OutputFile.keep();

  bool OffsetRequested = false;

  // Defaults to dumping only debug_info, unless: A) verbose mode is specified,
  // in which case all sections are dumped, or B) a specific section is
  // requested.
#define HANDLE_DWARF_SECTION(ENUM_NAME, ELF_NAME, CMDLINE_NAME, OPTION)        \
  if (Dump##ENUM_NAME.IsRequested) {                                           \
    DumpType |= DIDT_##ENUM_NAME;                                              \
    if (Dump##ENUM_NAME.HasValue) {                                            \
      DumpOffsets[DIDT_ID_##ENUM_NAME] = Dump##ENUM_NAME.Val;                  \
      OffsetRequested = true;                                                  \
    }                                                                          \
  }
#include "llvm/BinaryFormat/Dwarf.def"
#undef HANDLE_DWARF_SECTION
  if (DumpUUID)
    DumpType |= DIDT_UUID;
  if (DumpAll)
    DumpType = DIDT_All;
  if (DumpType == DIDT_Null) {
    if (Verbose || Verify)
      DumpType = DIDT_All;
    else
      DumpType = DIDT_DebugInfo;
  }

  // Unless dumping a specific DIE, default to --show-children.
  if (!ShowChildren && !Verify && !OffsetRequested && Name.empty() &&
      Find.empty() && !FindAllApple)
    ShowChildren = true;

  // Defaults to a.out if no filenames specified.
  if (InputFilenames.empty())
    InputFilenames.push_back("a.out");

  // Expand any .dSYM bundles to the individual object files contained therein.
  std::vector<std::string> Objects;
  for (const auto &F : InputFilenames) {
    if (auto DsymObjectsOrErr = MachOObjectFile::findDsymObjectMembers(F)) {
      if (DsymObjectsOrErr->empty())
        Objects.push_back(F);
      else
        llvm::append_range(Objects, *DsymObjectsOrErr);
    } else {
      error(DsymObjectsOrErr.takeError());
    }
  }

  bool Success = true;
  if (Verify) {
    if (!VerifyNumThreads)
      parallel::strategy =
          hardware_concurrency(hardware_concurrency().compute_thread_count());
    else
      parallel::strategy = hardware_concurrency(VerifyNumThreads);
    for (StringRef Object : Objects)
      Success &= handleFile(Object, verifyObjectFile, OutputFile.os());
  } else if (Statistics) {
    for (StringRef Object : Objects)
      Success &= handleFile(Object, collectStatsForObjectFile, OutputFile.os());
  } else if (ShowSectionSizes) {
    for (StringRef Object : Objects)
      Success &= handleFile(Object, collectObjectSectionSizes, OutputFile.os());
  } else if (ShowSources) {
    for (StringRef Object : Objects)
      Success &= handleFile(Object, collectObjectSources, OutputFile.os());
  } else {
    for (StringRef Object : Objects)
      Success &= handleFile(Object, dumpObjectFile, OutputFile.os());
  }

  return Success ? EXIT_SUCCESS : EXIT_FAILURE;
}