tools/llvm-objdump/ELFDump.cpp - llvm-project/llvm - Git at Google

 //===-- ELFDump.cpp - ELF-specific dumper -----------------------*- C++ -*-===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// This file implements the ELF-specific dumper for llvm-objdump.
 ///
 //===----------------------------------------------------------------------===//

 #include "ELFDump.h"

 #include "llvm-objdump.h"
 #include "llvm/Demangle/Demangle.h"
 #include "llvm/Object/ELFObjectFile.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"

 using namespace llvm;
 using namespace llvm::object;
 using namespace llvm::objdump;

 namespace {
 template <typename ELFT> class ELFDumper : public Dumper {
 public:
   ELFDumper(const ELFObjectFile<ELFT> &O) : Dumper(O), Obj(O) {}
   void printPrivateHeaders() override;
   void printDynamicRelocations() override;

 private:
   const ELFObjectFile<ELFT> &Obj;

   const ELFFile<ELFT> &getELFFile() const { return Obj.getELFFile(); }
   void printDynamicSection();
   void printProgramHeaders();
   void printSymbolVersion();
   void printSymbolVersionDependency(const typename ELFT::Shdr &Sec);
 };
 } // namespace

 template <class ELFT>
 static std::unique_ptr<Dumper> createDumper(const ELFObjectFile<ELFT> &Obj) {
   return std::make_unique<ELFDumper<ELFT>>(Obj);
 }

 std::unique_ptr<Dumper>
 objdump::createELFDumper(const object::ELFObjectFileBase &Obj) {
   if (const auto *O = dyn_cast<ELF32LEObjectFile>(&Obj))
     return createDumper(*O);
   if (const auto *O = dyn_cast<ELF32BEObjectFile>(&Obj))
     return createDumper(*O);
   if (const auto *O = dyn_cast<ELF64LEObjectFile>(&Obj))
     return createDumper(*O);
   return createDumper(cast<ELF64BEObjectFile>(Obj));
 }

 template <class ELFT>
 static Expected<StringRef> getDynamicStrTab(const ELFFile<ELFT> &Elf) {
   auto DynamicEntriesOrError = Elf.dynamicEntries();
   if (!DynamicEntriesOrError)
     return DynamicEntriesOrError.takeError();

   for (const typename ELFT::Dyn &Dyn : *DynamicEntriesOrError) {
     if (Dyn.d_tag == ELF::DT_STRTAB) {
       auto MappedAddrOrError = Elf.toMappedAddr(Dyn.getPtr());
       if (!MappedAddrOrError)
         return MappedAddrOrError.takeError();
       return StringRef(reinterpret_cast<const char *>(*MappedAddrOrError));
     }
   }

   // If the dynamic segment is not present, we fall back on the sections.
   auto SectionsOrError = Elf.sections();
   if (!SectionsOrError)
     return SectionsOrError.takeError();

   for (const typename ELFT::Shdr &Sec : *SectionsOrError) {
     if (Sec.sh_type == ELF::SHT_DYNSYM)
       return Elf.getStringTableForSymtab(Sec);
   }

   return createError("dynamic string table not found");
 }

 template <class ELFT>
 static Error getRelocationValueString(const ELFObjectFile<ELFT> *Obj,
                                       const RelocationRef &RelRef,
                                       SmallVectorImpl<char> &Result) {
   const ELFFile<ELFT> &EF = Obj->getELFFile();
   DataRefImpl Rel = RelRef.getRawDataRefImpl();
   auto SecOrErr = EF.getSection(Rel.d.a);
   if (!SecOrErr)
     return SecOrErr.takeError();

   int64_t Addend = 0;
   // If there is no Symbol associated with the relocation, we set the undef
   // boolean value to 'true'. This will prevent us from calling functions that
   // requires the relocation to be associated with a symbol.
   //
   // In SHT_REL case we would need to read the addend from section data.
   // GNU objdump does not do that and we just follow for simplicity atm.
   bool Undef = false;
   if ((*SecOrErr)->sh_type == ELF::SHT_RELA) {
     const typename ELFT::Rela *ERela = Obj->getRela(Rel);
     Addend = ERela->r_addend;
     Undef = ERela->getSymbol(false) == 0;
   } else if ((*SecOrErr)->sh_type == ELF::SHT_REL) {
     const typename ELFT::Rel *ERel = Obj->getRel(Rel);
     Undef = ERel->getSymbol(false) == 0;
   } else {
     return make_error<BinaryError>();
   }

   // Default scheme is to print Target, as well as "+ <addend>" for nonzero
   // addend. Should be acceptable for all normal purposes.
   std::string FmtBuf;
   raw_string_ostream Fmt(FmtBuf);

   if (!Undef) {
     symbol_iterator SI = RelRef.getSymbol();
     Expected<const typename ELFT::Sym *> SymOrErr =
         Obj->getSymbol(SI->getRawDataRefImpl());
     // TODO: test this error.
     if (!SymOrErr)
       return SymOrErr.takeError();

     if ((*SymOrErr)->getType() == ELF::STT_SECTION) {
       Expected<section_iterator> SymSI = SI->getSection();
       if (!SymSI)
         return SymSI.takeError();
       const typename ELFT::Shdr *SymSec =
           Obj->getSection((*SymSI)->getRawDataRefImpl());
       auto SecName = EF.getSectionName(*SymSec);
       if (!SecName)
         return SecName.takeError();
       Fmt << *SecName;
     } else {
       Expected<StringRef> SymName = SI->getName();
       if (!SymName)
         return SymName.takeError();
       Fmt << (Demangle ? demangle(*SymName) : *SymName);
     }
   } else {
     Fmt << "*ABS*";
   }
   if (Addend != 0) {
       Fmt << (Addend < 0
           ? "-"
           : "+") << format("0x%" PRIx64,
                           (Addend < 0 ? -(uint64_t)Addend : (uint64_t)Addend));
   }
   Fmt.flush();
   Result.append(FmtBuf.begin(), FmtBuf.end());
   return Error::success();
 }

 Error objdump::getELFRelocationValueString(const ELFObjectFileBase *Obj,
                                            const RelocationRef &Rel,
                                            SmallVectorImpl<char> &Result) {
   if (auto *ELF32LE = dyn_cast<ELF32LEObjectFile>(Obj))
     return getRelocationValueString(ELF32LE, Rel, Result);
   if (auto *ELF64LE = dyn_cast<ELF64LEObjectFile>(Obj))
     return getRelocationValueString(ELF64LE, Rel, Result);
   if (auto *ELF32BE = dyn_cast<ELF32BEObjectFile>(Obj))
     return getRelocationValueString(ELF32BE, Rel, Result);
   auto *ELF64BE = cast<ELF64BEObjectFile>(Obj);
   return getRelocationValueString(ELF64BE, Rel, Result);
 }

 template <class ELFT>
 static uint64_t getSectionLMA(const ELFFile<ELFT> &Obj,
                               const object::ELFSectionRef &Sec) {
   auto PhdrRangeOrErr = Obj.program_headers();
   if (!PhdrRangeOrErr)
     report_fatal_error(Twine(toString(PhdrRangeOrErr.takeError())));

   // Search for a PT_LOAD segment containing the requested section. Use this
   // segment's p_addr to calculate the section's LMA.
   for (const typename ELFT::Phdr &Phdr : *PhdrRangeOrErr)
     if ((Phdr.p_type == ELF::PT_LOAD) &&
         (isSectionInSegment<ELFT>(
             Phdr, *cast<const ELFObjectFile<ELFT>>(Sec.getObject())
                        ->getSection(Sec.getRawDataRefImpl()))))
       return Sec.getAddress() - Phdr.p_vaddr + Phdr.p_paddr;

   // Return section's VMA if it isn't in a PT_LOAD segment.
   return Sec.getAddress();
 }

 uint64_t objdump::getELFSectionLMA(const object::ELFSectionRef &Sec) {
   if (const auto *ELFObj = dyn_cast<ELF32LEObjectFile>(Sec.getObject()))
     return getSectionLMA(ELFObj->getELFFile(), Sec);
   else if (const auto *ELFObj = dyn_cast<ELF32BEObjectFile>(Sec.getObject()))
     return getSectionLMA(ELFObj->getELFFile(), Sec);
   else if (const auto *ELFObj = dyn_cast<ELF64LEObjectFile>(Sec.getObject()))
     return getSectionLMA(ELFObj->getELFFile(), Sec);
   const auto *ELFObj = cast<ELF64BEObjectFile>(Sec.getObject());
   return getSectionLMA(ELFObj->getELFFile(), Sec);
 }

 template <class ELFT> void ELFDumper<ELFT>::printDynamicSection() {
   const ELFFile<ELFT> &Elf = getELFFile();
   auto DynamicEntriesOrErr = Elf.dynamicEntries();
   if (!DynamicEntriesOrErr) {
     reportWarning(toString(DynamicEntriesOrErr.takeError()), Obj.getFileName());
     return;
   }
   ArrayRef<typename ELFT::Dyn> DynamicEntries = *DynamicEntriesOrErr;

   // Find the maximum tag name length to format the value column properly.
   size_t MaxLen = 0;
   for (const typename ELFT::Dyn &Dyn : DynamicEntries)
     MaxLen = std::max(MaxLen, Elf.getDynamicTagAsString(Dyn.d_tag).size());
   std::string TagFmt = "  %-" + std::to_string(MaxLen) + "s ";

   outs() << "\nDynamic Section:\n";
   for (const typename ELFT::Dyn &Dyn : DynamicEntries) {
     if (Dyn.d_tag == ELF::DT_NULL)
       continue;

     std::string Str = Elf.getDynamicTagAsString(Dyn.d_tag);

     const char *Fmt =
         ELFT::Is64Bits ? "0x%016" PRIx64 "\n" : "0x%08" PRIx64 "\n";
     if (Dyn.d_tag == ELF::DT_NEEDED || Dyn.d_tag == ELF::DT_RPATH ||
         Dyn.d_tag == ELF::DT_RUNPATH || Dyn.d_tag == ELF::DT_SONAME ||
         Dyn.d_tag == ELF::DT_AUXILIARY || Dyn.d_tag == ELF::DT_FILTER) {
       Expected<StringRef> StrTabOrErr = getDynamicStrTab(Elf);
       if (StrTabOrErr) {
         const char *Data = StrTabOrErr->data();
         outs() << format(TagFmt.c_str(), Str.c_str()) << Data + Dyn.getVal()
                << "\n";
         continue;
       }
       reportWarning(toString(StrTabOrErr.takeError()), Obj.getFileName());
       consumeError(StrTabOrErr.takeError());
     }
     outs() << format(TagFmt.c_str(), Str.c_str())
            << format(Fmt, (uint64_t)Dyn.getVal());
   }
 }

 template <class ELFT> void ELFDumper<ELFT>::printProgramHeaders() {
   outs() << "\nProgram Header:\n";
   auto ProgramHeaderOrError = getELFFile().program_headers();
   if (!ProgramHeaderOrError) {
     reportWarning("unable to read program headers: " +
                       toString(ProgramHeaderOrError.takeError()),
                   Obj.getFileName());
     return;
   }

   for (const typename ELFT::Phdr &Phdr : *ProgramHeaderOrError) {
     switch (Phdr.p_type) {
     case ELF::PT_DYNAMIC:
       outs() << " DYNAMIC ";
       break;
     case ELF::PT_GNU_EH_FRAME:
       outs() << "EH_FRAME ";
       break;
     case ELF::PT_GNU_RELRO:
       outs() << "   RELRO ";
       break;
     case ELF::PT_GNU_PROPERTY:
       outs() << "   PROPERTY ";
       break;
     case ELF::PT_GNU_STACK:
       outs() << "   STACK ";
       break;
     case ELF::PT_INTERP:
       outs() << "  INTERP ";
       break;
     case ELF::PT_LOAD:
       outs() << "    LOAD ";
       break;
     case ELF::PT_NOTE:
       outs() << "    NOTE ";
       break;
     case ELF::PT_OPENBSD_BOOTDATA:
       outs() << "OPENBSD_BOOTDATA ";
       break;
     case ELF::PT_OPENBSD_MUTABLE:
       outs() << "OPENBSD_MUTABLE ";
       break;
     case ELF::PT_OPENBSD_NOBTCFI:
       outs() << "OPENBSD_NOBTCFI ";
       break;
     case ELF::PT_OPENBSD_RANDOMIZE:
       outs() << "OPENBSD_RANDOMIZE ";
       break;
     case ELF::PT_OPENBSD_SYSCALLS:
       outs() << "OPENBSD_SYSCALLS ";
       break;
     case ELF::PT_OPENBSD_WXNEEDED:
       outs() << "OPENBSD_WXNEEDED ";
       break;
     case ELF::PT_PHDR:
       outs() << "    PHDR ";
       break;
     case ELF::PT_TLS:
       outs() << "    TLS ";
       break;
     default:
       outs() << " UNKNOWN ";
     }

     const char *Fmt = ELFT::Is64Bits ? "0x%016" PRIx64 " " : "0x%08" PRIx64 " ";

     outs() << "off    " << format(Fmt, (uint64_t)Phdr.p_offset) << "vaddr "
            << format(Fmt, (uint64_t)Phdr.p_vaddr) << "paddr "
            << format(Fmt, (uint64_t)Phdr.p_paddr)
            << format("align 2**%u\n", llvm::countr_zero<uint64_t>(Phdr.p_align))
            << "         filesz " << format(Fmt, (uint64_t)Phdr.p_filesz)
            << "memsz " << format(Fmt, (uint64_t)Phdr.p_memsz) << "flags "
            << ((Phdr.p_flags & ELF::PF_R) ? "r" : "-")
            << ((Phdr.p_flags & ELF::PF_W) ? "w" : "-")
            << ((Phdr.p_flags & ELF::PF_X) ? "x" : "-") << "\n";
   }
 }

 template <typename ELFT> void ELFDumper<ELFT>::printDynamicRelocations() {
   if (!any_of(Obj.sections(), [](const ELFSectionRef Sec) {
         return Sec.getType() == ELF::SHT_DYNAMIC;
       })) {
     reportError(Obj.getFileName(), "not a dynamic object");
     return;
   }

   std::vector<SectionRef> DynRelSec =
       cast<ObjectFile>(Obj).dynamic_relocation_sections();
   if (DynRelSec.empty())
     return;

   outs() << "\nDYNAMIC RELOCATION RECORDS\n";
   const uint32_t OffsetPadding = (Obj.getBytesInAddress() > 4 ? 16 : 8);
   const uint32_t TypePadding = 24;
   outs() << left_justify("OFFSET", OffsetPadding) << ' '
          << left_justify("TYPE", TypePadding) << " VALUE\n";

   StringRef Fmt = Obj.getBytesInAddress() > 4 ? "%016" PRIx64 : "%08" PRIx64;
   for (const SectionRef &Section : DynRelSec)
     for (const RelocationRef &Reloc : Section.relocations()) {
       uint64_t Address = Reloc.getOffset();
       SmallString<32> RelocName;
       SmallString<32> ValueStr;
       Reloc.getTypeName(RelocName);
       if (Error E = getELFRelocationValueString(&Obj, Reloc, ValueStr))
         reportError(std::move(E), Obj.getFileName());
       outs() << format(Fmt.data(), Address) << ' '
              << left_justify(RelocName, TypePadding) << ' ' << ValueStr << '\n';
     }
 }

 template <class ELFT>
 void ELFDumper<ELFT>::printSymbolVersionDependency(
     const typename ELFT::Shdr &Sec) {
   outs() << "\nVersion References:\n";
   Expected<std::vector<VerNeed>> V =
       getELFFile().getVersionDependencies(Sec, this->WarningHandler);
   if (!V) {
     reportWarning(toString(V.takeError()), Obj.getFileName());
     return;
   }

   raw_fd_ostream &OS = outs();
   for (const VerNeed &VN : *V) {
     OS << "  required from " << VN.File << ":\n";
     for (const VernAux &Aux : VN.AuxV)
       OS << format("    0x%08x 0x%02x %02u %s\n", Aux.Hash, Aux.Flags,
                    Aux.Other, Aux.Name.c_str());
   }
 }

 template <class ELFT>
 static void printSymbolVersionDefinition(const typename ELFT::Shdr &Shdr,
                                          ArrayRef<uint8_t> Contents,
                                          StringRef StrTab) {
   outs() << "\nVersion definitions:\n";

   const uint8_t *Buf = Contents.data();
   uint32_t VerdefIndex = 1;
   // sh_info contains the number of entries in the SHT_GNU_verdef section. To
   // make the index column have consistent width, we should insert blank spaces
   // according to sh_info.
   uint16_t VerdefIndexWidth = std::to_string(Shdr.sh_info).size();
   while (Buf) {
     auto *Verdef = reinterpret_cast<const typename ELFT::Verdef *>(Buf);
     outs() << format_decimal(VerdefIndex++, VerdefIndexWidth) << " "
            << format("0x%02" PRIx16 " ", (uint16_t)Verdef->vd_flags)
            << format("0x%08" PRIx32 " ", (uint32_t)Verdef->vd_hash);

     const uint8_t *BufAux = Buf + Verdef->vd_aux;
     uint16_t VerdauxIndex = 0;
     while (BufAux) {
       auto *Verdaux = reinterpret_cast<const typename ELFT::Verdaux *>(BufAux);
       if (VerdauxIndex)
         outs() << std::string(VerdefIndexWidth + 17, ' ');
       outs() << StringRef(StrTab.drop_front(Verdaux->vda_name).data()) << '\n';
       BufAux = Verdaux->vda_next ? BufAux + Verdaux->vda_next : nullptr;
       ++VerdauxIndex;
     }
     Buf = Verdef->vd_next ? Buf + Verdef->vd_next : nullptr;
   }
 }

 template <class ELFT> void ELFDumper<ELFT>::printSymbolVersion() {
   const ELFFile<ELFT> &Elf = getELFFile();
   StringRef FileName = Obj.getFileName();
   ArrayRef<typename ELFT::Shdr> Sections =
       unwrapOrError(Elf.sections(), FileName);
   for (const typename ELFT::Shdr &Shdr : Sections) {
     if (Shdr.sh_type != ELF::SHT_GNU_verneed &&
         Shdr.sh_type != ELF::SHT_GNU_verdef)
       continue;

     ArrayRef<uint8_t> Contents =
         unwrapOrError(Elf.getSectionContents(Shdr), FileName);
     const typename ELFT::Shdr *StrTabSec =
         unwrapOrError(Elf.getSection(Shdr.sh_link), FileName);
     StringRef StrTab = unwrapOrError(Elf.getStringTable(*StrTabSec), FileName);

     if (Shdr.sh_type == ELF::SHT_GNU_verneed)
       printSymbolVersionDependency(Shdr);
     else
       printSymbolVersionDefinition<ELFT>(Shdr, Contents, StrTab);
   }
 }

 template <class ELFT> void ELFDumper<ELFT>::printPrivateHeaders() {
   printProgramHeaders();
   printDynamicSection();
   printSymbolVersion();
 }
	//===-- ELFDump.cpp - ELF-specific dumper ------------------------ C++ --===//
	//
	// 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
	//
	//===----------------------------------------------------------------------===//
	///
	/// \file
	/// This file implements the ELF-specific dumper for llvm-objdump.
	///
	//===----------------------------------------------------------------------===//

	#include "ELFDump.h"

	#include "llvm-objdump.h"
	#include "llvm/Demangle/Demangle.h"
	#include "llvm/Object/ELFObjectFile.h"
	#include "llvm/Support/Format.h"
	#include "llvm/Support/MathExtras.h"
	#include "llvm/Support/raw_ostream.h"

	using namespace llvm;
	using namespace llvm::object;
	using namespace llvm::objdump;

	namespace {
	template <typename ELFT> class ELFDumper : public Dumper {
	public:
	ELFDumper(const ELFObjectFile<ELFT> &O) : Dumper(O), Obj(O) {}
	void printPrivateHeaders() override;
	void printDynamicRelocations() override;

	private:
	const ELFObjectFile<ELFT> &Obj;

	const ELFFile<ELFT> &getELFFile() const { return Obj.getELFFile(); }
	void printDynamicSection();
	void printProgramHeaders();
	void printSymbolVersion();
	void printSymbolVersionDependency(const typename ELFT::Shdr &Sec);
	};
	} // namespace

	template <class ELFT>
	static std::unique_ptr<Dumper> createDumper(const ELFObjectFile<ELFT> &Obj) {
	return std::make_unique<ELFDumper<ELFT>>(Obj);
	}

	std::unique_ptr<Dumper>
	objdump::createELFDumper(const object::ELFObjectFileBase &Obj) {
	if (const auto *O = dyn_cast<ELF32LEObjectFile>(&Obj))
	return createDumper(*O);
	if (const auto *O = dyn_cast<ELF32BEObjectFile>(&Obj))
	return createDumper(*O);
	if (const auto *O = dyn_cast<ELF64LEObjectFile>(&Obj))
	return createDumper(*O);
	return createDumper(cast<ELF64BEObjectFile>(Obj));
	}

	template <class ELFT>
	static Expected<StringRef> getDynamicStrTab(const ELFFile<ELFT> &Elf) {
	auto DynamicEntriesOrError = Elf.dynamicEntries();
	if (!DynamicEntriesOrError)
	return DynamicEntriesOrError.takeError();

	for (const typename ELFT::Dyn &Dyn : *DynamicEntriesOrError) {
	if (Dyn.d_tag == ELF::DT_STRTAB) {
	auto MappedAddrOrError = Elf.toMappedAddr(Dyn.getPtr());
	if (!MappedAddrOrError)
	return MappedAddrOrError.takeError();
	return StringRef(reinterpret_cast<const char >(MappedAddrOrError));
	}
	}

	// If the dynamic segment is not present, we fall back on the sections.
	auto SectionsOrError = Elf.sections();
	if (!SectionsOrError)
	return SectionsOrError.takeError();

	for (const typename ELFT::Shdr &Sec : *SectionsOrError) {
	if (Sec.sh_type == ELF::SHT_DYNSYM)
	return Elf.getStringTableForSymtab(Sec);
	}

	return createError("dynamic string table not found");
	}

	template <class ELFT>
	static Error getRelocationValueString(const ELFObjectFile<ELFT> *Obj,
	const RelocationRef &RelRef,
	SmallVectorImpl<char> &Result) {
	const ELFFile<ELFT> &EF = Obj->getELFFile();
	DataRefImpl Rel = RelRef.getRawDataRefImpl();
	auto SecOrErr = EF.getSection(Rel.d.a);
	if (!SecOrErr)
	return SecOrErr.takeError();

	int64_t Addend = 0;
	// If there is no Symbol associated with the relocation, we set the undef
	// boolean value to 'true'. This will prevent us from calling functions that
	// requires the relocation to be associated with a symbol.
	//
	// In SHT_REL case we would need to read the addend from section data.
	// GNU objdump does not do that and we just follow for simplicity atm.
	bool Undef = false;
	if ((*SecOrErr)->sh_type == ELF::SHT_RELA) {
	const typename ELFT::Rela *ERela = Obj->getRela(Rel);
	Addend = ERela->r_addend;
	Undef = ERela->getSymbol(false) == 0;
	} else if ((*SecOrErr)->sh_type == ELF::SHT_REL) {
	const typename ELFT::Rel *ERel = Obj->getRel(Rel);
	Undef = ERel->getSymbol(false) == 0;
	} else {
	return make_error<BinaryError>();
	}

	// Default scheme is to print Target, as well as "+ <addend>" for nonzero
	// addend. Should be acceptable for all normal purposes.
	std::string FmtBuf;
	raw_string_ostream Fmt(FmtBuf);

	if (!Undef) {
	symbol_iterator SI = RelRef.getSymbol();
	Expected<const typename ELFT::Sym *> SymOrErr =
	Obj->getSymbol(SI->getRawDataRefImpl());
	// TODO: test this error.
	if (!SymOrErr)
	return SymOrErr.takeError();

	if ((*SymOrErr)->getType() == ELF::STT_SECTION) {
	Expected<section_iterator> SymSI = SI->getSection();
	if (!SymSI)
	return SymSI.takeError();
	const typename ELFT::Shdr *SymSec =
	Obj->getSection((*SymSI)->getRawDataRefImpl());
	auto SecName = EF.getSectionName(*SymSec);
	if (!SecName)
	return SecName.takeError();
	Fmt << *SecName;
	} else {
	Expected<StringRef> SymName = SI->getName();
	if (!SymName)
	return SymName.takeError();
	Fmt << (Demangle ? demangle(SymName) : SymName);
	}
	} else {
	Fmt << "ABS";
	}
	if (Addend != 0) {
	Fmt << (Addend < 0
	? "-"
	: "+") << format("0x%" PRIx64,
	(Addend < 0 ? -(uint64_t)Addend : (uint64_t)Addend));
	}
	Fmt.flush();
	Result.append(FmtBuf.begin(), FmtBuf.end());
	return Error::success();
	}

	Error objdump::getELFRelocationValueString(const ELFObjectFileBase *Obj,
	const RelocationRef &Rel,
	SmallVectorImpl<char> &Result) {
	if (auto *ELF32LE = dyn_cast<ELF32LEObjectFile>(Obj))
	return getRelocationValueString(ELF32LE, Rel, Result);
	if (auto *ELF64LE = dyn_cast<ELF64LEObjectFile>(Obj))
	return getRelocationValueString(ELF64LE, Rel, Result);
	if (auto *ELF32BE = dyn_cast<ELF32BEObjectFile>(Obj))
	return getRelocationValueString(ELF32BE, Rel, Result);
	auto *ELF64BE = cast<ELF64BEObjectFile>(Obj);
	return getRelocationValueString(ELF64BE, Rel, Result);
	}

	template <class ELFT>
	static uint64_t getSectionLMA(const ELFFile<ELFT> &Obj,
	const object::ELFSectionRef &Sec) {
	auto PhdrRangeOrErr = Obj.program_headers();
	if (!PhdrRangeOrErr)
	report_fatal_error(Twine(toString(PhdrRangeOrErr.takeError())));

	// Search for a PT_LOAD segment containing the requested section. Use this
	// segment's p_addr to calculate the section's LMA.
	for (const typename ELFT::Phdr &Phdr : *PhdrRangeOrErr)
	if ((Phdr.p_type == ELF::PT_LOAD) &&
	(isSectionInSegment<ELFT>(
	Phdr, *cast<const ELFObjectFile<ELFT>>(Sec.getObject())
	->getSection(Sec.getRawDataRefImpl()))))
	return Sec.getAddress() - Phdr.p_vaddr + Phdr.p_paddr;

	// Return section's VMA if it isn't in a PT_LOAD segment.
	return Sec.getAddress();
	}

	uint64_t objdump::getELFSectionLMA(const object::ELFSectionRef &Sec) {
	if (const auto *ELFObj = dyn_cast<ELF32LEObjectFile>(Sec.getObject()))
	return getSectionLMA(ELFObj->getELFFile(), Sec);
	else if (const auto *ELFObj = dyn_cast<ELF32BEObjectFile>(Sec.getObject()))
	return getSectionLMA(ELFObj->getELFFile(), Sec);
	else if (const auto *ELFObj = dyn_cast<ELF64LEObjectFile>(Sec.getObject()))
	return getSectionLMA(ELFObj->getELFFile(), Sec);
	const auto *ELFObj = cast<ELF64BEObjectFile>(Sec.getObject());
	return getSectionLMA(ELFObj->getELFFile(), Sec);
	}

	template <class ELFT> void ELFDumper<ELFT>::printDynamicSection() {
	const ELFFile<ELFT> &Elf = getELFFile();
	auto DynamicEntriesOrErr = Elf.dynamicEntries();
	if (!DynamicEntriesOrErr) {
	reportWarning(toString(DynamicEntriesOrErr.takeError()), Obj.getFileName());
	return;
	}
	ArrayRef<typename ELFT::Dyn> DynamicEntries = *DynamicEntriesOrErr;

	// Find the maximum tag name length to format the value column properly.
	size_t MaxLen = 0;
	for (const typename ELFT::Dyn &Dyn : DynamicEntries)
	MaxLen = std::max(MaxLen, Elf.getDynamicTagAsString(Dyn.d_tag).size());
	std::string TagFmt = " %-" + std::to_string(MaxLen) + "s ";

	outs() << "\nDynamic Section:\n";
	for (const typename ELFT::Dyn &Dyn : DynamicEntries) {
	if (Dyn.d_tag == ELF::DT_NULL)
	continue;

	std::string Str = Elf.getDynamicTagAsString(Dyn.d_tag);

	const char *Fmt =
	ELFT::Is64Bits ? "0x%016" PRIx64 "\n" : "0x%08" PRIx64 "\n";
	if (Dyn.d_tag == ELF::DT_NEEDED \|\| Dyn.d_tag == ELF::DT_RPATH \|\|
	Dyn.d_tag == ELF::DT_RUNPATH \|\| Dyn.d_tag == ELF::DT_SONAME \|\|
	Dyn.d_tag == ELF::DT_AUXILIARY \|\| Dyn.d_tag == ELF::DT_FILTER) {
	Expected<StringRef> StrTabOrErr = getDynamicStrTab(Elf);
	if (StrTabOrErr) {
	const char *Data = StrTabOrErr->data();
	outs() << format(TagFmt.c_str(), Str.c_str()) << Data + Dyn.getVal()
	<< "\n";
	continue;
	}
	reportWarning(toString(StrTabOrErr.takeError()), Obj.getFileName());
	consumeError(StrTabOrErr.takeError());
	}
	outs() << format(TagFmt.c_str(), Str.c_str())
	<< format(Fmt, (uint64_t)Dyn.getVal());
	}
	}

	template <class ELFT> void ELFDumper<ELFT>::printProgramHeaders() {
	outs() << "\nProgram Header:\n";
	auto ProgramHeaderOrError = getELFFile().program_headers();
	if (!ProgramHeaderOrError) {
	reportWarning("unable to read program headers: " +
	toString(ProgramHeaderOrError.takeError()),
	Obj.getFileName());
	return;
	}

	for (const typename ELFT::Phdr &Phdr : *ProgramHeaderOrError) {
	switch (Phdr.p_type) {
	case ELF::PT_DYNAMIC:
	outs() << " DYNAMIC ";
	break;
	case ELF::PT_GNU_EH_FRAME:
	outs() << "EH_FRAME ";
	break;
	case ELF::PT_GNU_RELRO:
	outs() << " RELRO ";
	break;
	case ELF::PT_GNU_PROPERTY:
	outs() << " PROPERTY ";
	break;
	case ELF::PT_GNU_STACK:
	outs() << " STACK ";
	break;
	case ELF::PT_INTERP:
	outs() << " INTERP ";
	break;
	case ELF::PT_LOAD:
	outs() << " LOAD ";
	break;
	case ELF::PT_NOTE:
	outs() << " NOTE ";
	break;
	case ELF::PT_OPENBSD_BOOTDATA:
	outs() << "OPENBSD_BOOTDATA ";
	break;
	case ELF::PT_OPENBSD_MUTABLE:
	outs() << "OPENBSD_MUTABLE ";
	break;
	case ELF::PT_OPENBSD_NOBTCFI:
	outs() << "OPENBSD_NOBTCFI ";
	break;
	case ELF::PT_OPENBSD_RANDOMIZE:
	outs() << "OPENBSD_RANDOMIZE ";
	break;
	case ELF::PT_OPENBSD_SYSCALLS:
	outs() << "OPENBSD_SYSCALLS ";
	break;
	case ELF::PT_OPENBSD_WXNEEDED:
	outs() << "OPENBSD_WXNEEDED ";
	break;
	case ELF::PT_PHDR:
	outs() << " PHDR ";
	break;
	case ELF::PT_TLS:
	outs() << " TLS ";
	break;
	default:
	outs() << " UNKNOWN ";
	}

	const char *Fmt = ELFT::Is64Bits ? "0x%016" PRIx64 " " : "0x%08" PRIx64 " ";

	outs() << "off " << format(Fmt, (uint64_t)Phdr.p_offset) << "vaddr "
	<< format(Fmt, (uint64_t)Phdr.p_vaddr) << "paddr "
	<< format(Fmt, (uint64_t)Phdr.p_paddr)
	<< format("align 2**%u\n", llvm::countr_zero<uint64_t>(Phdr.p_align))
	<< " filesz " << format(Fmt, (uint64_t)Phdr.p_filesz)
	<< "memsz " << format(Fmt, (uint64_t)Phdr.p_memsz) << "flags "
	<< ((Phdr.p_flags & ELF::PF_R) ? "r" : "-")
	<< ((Phdr.p_flags & ELF::PF_W) ? "w" : "-")
	<< ((Phdr.p_flags & ELF::PF_X) ? "x" : "-") << "\n";
	}
	}

	template <typename ELFT> void ELFDumper<ELFT>::printDynamicRelocations() {
	if (!any_of(Obj.sections(), [](const ELFSectionRef Sec) {
	return Sec.getType() == ELF::SHT_DYNAMIC;
	})) {
	reportError(Obj.getFileName(), "not a dynamic object");
	return;
	}

	std::vector<SectionRef> DynRelSec =
	cast<ObjectFile>(Obj).dynamic_relocation_sections();
	if (DynRelSec.empty())
	return;

	outs() << "\nDYNAMIC RELOCATION RECORDS\n";
	const uint32_t OffsetPadding = (Obj.getBytesInAddress() > 4 ? 16 : 8);
	const uint32_t TypePadding = 24;
	outs() << left_justify("OFFSET", OffsetPadding) << ' '
	<< left_justify("TYPE", TypePadding) << " VALUE\n";

	StringRef Fmt = Obj.getBytesInAddress() > 4 ? "%016" PRIx64 : "%08" PRIx64;
	for (const SectionRef &Section : DynRelSec)
	for (const RelocationRef &Reloc : Section.relocations()) {
	uint64_t Address = Reloc.getOffset();
	SmallString<32> RelocName;
	SmallString<32> ValueStr;
	Reloc.getTypeName(RelocName);
	if (Error E = getELFRelocationValueString(&Obj, Reloc, ValueStr))
	reportError(std::move(E), Obj.getFileName());
	outs() << format(Fmt.data(), Address) << ' '
	<< left_justify(RelocName, TypePadding) << ' ' << ValueStr << '\n';
	}
	}

	template <class ELFT>
	void ELFDumper<ELFT>::printSymbolVersionDependency(
	const typename ELFT::Shdr &Sec) {
	outs() << "\nVersion References:\n";
	Expected<std::vector<VerNeed>> V =
	getELFFile().getVersionDependencies(Sec, this->WarningHandler);
	if (!V) {
	reportWarning(toString(V.takeError()), Obj.getFileName());
	return;
	}

	raw_fd_ostream &OS = outs();
	for (const VerNeed &VN : *V) {
	OS << " required from " << VN.File << ":\n";
	for (const VernAux &Aux : VN.AuxV)
	OS << format(" 0x%08x 0x%02x %02u %s\n", Aux.Hash, Aux.Flags,
	Aux.Other, Aux.Name.c_str());
	}
	}

	template <class ELFT>
	static void printSymbolVersionDefinition(const typename ELFT::Shdr &Shdr,
	ArrayRef<uint8_t> Contents,
	StringRef StrTab) {
	outs() << "\nVersion definitions:\n";

	const uint8_t *Buf = Contents.data();
	uint32_t VerdefIndex = 1;
	// sh_info contains the number of entries in the SHT_GNU_verdef section. To
	// make the index column have consistent width, we should insert blank spaces
	// according to sh_info.
	uint16_t VerdefIndexWidth = std::to_string(Shdr.sh_info).size();
	while (Buf) {
	auto Verdef = reinterpret_cast<const typename ELFT::Verdef >(Buf);
	outs() << format_decimal(VerdefIndex++, VerdefIndexWidth) << " "
	<< format("0x%02" PRIx16 " ", (uint16_t)Verdef->vd_flags)
	<< format("0x%08" PRIx32 " ", (uint32_t)Verdef->vd_hash);

	const uint8_t *BufAux = Buf + Verdef->vd_aux;
	uint16_t VerdauxIndex = 0;
	while (BufAux) {
	auto Verdaux = reinterpret_cast<const typename ELFT::Verdaux >(BufAux);
	if (VerdauxIndex)
	outs() << std::string(VerdefIndexWidth + 17, ' ');
	outs() << StringRef(StrTab.drop_front(Verdaux->vda_name).data()) << '\n';
	BufAux = Verdaux->vda_next ? BufAux + Verdaux->vda_next : nullptr;
	++VerdauxIndex;
	}
	Buf = Verdef->vd_next ? Buf + Verdef->vd_next : nullptr;
	}
	}

	template <class ELFT> void ELFDumper<ELFT>::printSymbolVersion() {
	const ELFFile<ELFT> &Elf = getELFFile();
	StringRef FileName = Obj.getFileName();
	ArrayRef<typename ELFT::Shdr> Sections =
	unwrapOrError(Elf.sections(), FileName);
	for (const typename ELFT::Shdr &Shdr : Sections) {
	if (Shdr.sh_type != ELF::SHT_GNU_verneed &&
	Shdr.sh_type != ELF::SHT_GNU_verdef)
	continue;

	ArrayRef<uint8_t> Contents =
	unwrapOrError(Elf.getSectionContents(Shdr), FileName);
	const typename ELFT::Shdr *StrTabSec =
	unwrapOrError(Elf.getSection(Shdr.sh_link), FileName);
	StringRef StrTab = unwrapOrError(Elf.getStringTable(*StrTabSec), FileName);

	if (Shdr.sh_type == ELF::SHT_GNU_verneed)
	printSymbolVersionDependency(Shdr);
	else
	printSymbolVersionDefinition<ELFT>(Shdr, Contents, StrTab);
	}
	}

	template <class ELFT> void ELFDumper<ELFT>::printPrivateHeaders() {
	printProgramHeaders();
	printDynamicSection();
	printSymbolVersion();
	}