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			376 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C++
		
	
	
	
			
		
		
	
	
			376 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C++
		
	
	
	
| //===-- ELFDump.cpp - ELF-specific dumper -----------------------*- C++ -*-===//
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| //
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| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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| // See https://llvm.org/LICENSE.txt for license information.
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| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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| //
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| //===----------------------------------------------------------------------===//
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| ///
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| /// \file
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| /// This file implements the ELF-specific dumper for llvm-objdump.
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| ///
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| //===----------------------------------------------------------------------===//
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| 
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| #include "llvm-objdump.h"
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| #include "llvm/Demangle/Demangle.h"
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| #include "llvm/Object/ELFObjectFile.h"
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| #include "llvm/Support/Format.h"
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| #include "llvm/Support/MathExtras.h"
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| #include "llvm/Support/raw_ostream.h"
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| 
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| using namespace llvm::object;
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| 
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| namespace llvm {
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| template <class ELFT>
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| static Expected<StringRef> getDynamicStrTab(const ELFFile<ELFT> *Elf) {
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|   auto DynamicEntriesOrError = Elf->dynamicEntries();
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|   if (!DynamicEntriesOrError)
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|     return DynamicEntriesOrError.takeError();
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| 
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|   for (const typename ELFT::Dyn &Dyn : *DynamicEntriesOrError) {
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|     if (Dyn.d_tag == ELF::DT_STRTAB) {
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|       auto MappedAddrOrError = Elf->toMappedAddr(Dyn.getPtr());
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|       if (!MappedAddrOrError)
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|         consumeError(MappedAddrOrError.takeError());
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|       return StringRef(reinterpret_cast<const char *>(*MappedAddrOrError));
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|     }
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|   }
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| 
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|   // If the dynamic segment is not present, we fall back on the sections.
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|   auto SectionsOrError = Elf->sections();
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|   if (!SectionsOrError)
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|     return SectionsOrError.takeError();
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| 
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|   for (const typename ELFT::Shdr &Sec : *SectionsOrError) {
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|     if (Sec.sh_type == ELF::SHT_DYNSYM)
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|       return Elf->getStringTableForSymtab(Sec);
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|   }
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| 
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|   return createError("dynamic string table not found");
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| }
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| 
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| template <class ELFT>
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| static Error getRelocationValueString(const ELFObjectFile<ELFT> *Obj,
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|                                       const RelocationRef &RelRef,
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|                                       SmallVectorImpl<char> &Result) {
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|   const ELFFile<ELFT> &EF = *Obj->getELFFile();
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|   DataRefImpl Rel = RelRef.getRawDataRefImpl();
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|   auto SecOrErr = EF.getSection(Rel.d.a);
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|   if (!SecOrErr)
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|     return SecOrErr.takeError();
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| 
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|   int64_t Addend = 0;
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|   // If there is no Symbol associated with the relocation, we set the undef
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|   // boolean value to 'true'. This will prevent us from calling functions that
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|   // requires the relocation to be associated with a symbol.
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|   //
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|   // In SHT_REL case we would need to read the addend from section data.
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|   // GNU objdump does not do that and we just follow for simplicity atm.
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|   bool Undef = false;
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|   if ((*SecOrErr)->sh_type == ELF::SHT_RELA) {
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|     const typename ELFT::Rela *ERela = Obj->getRela(Rel);
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|     Addend = ERela->r_addend;
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|     Undef = ERela->getSymbol(false) == 0;
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|   } else if ((*SecOrErr)->sh_type != ELF::SHT_REL) {
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|     return make_error<BinaryError>();
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|   }
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| 
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|   // Default scheme is to print Target, as well as "+ <addend>" for nonzero
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|   // addend. Should be acceptable for all normal purposes.
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|   std::string FmtBuf;
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|   raw_string_ostream Fmt(FmtBuf);
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| 
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|   if (!Undef) {
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|     symbol_iterator SI = RelRef.getSymbol();
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|     const typename ELFT::Sym *Sym = Obj->getSymbol(SI->getRawDataRefImpl());
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|     if (Sym->getType() == ELF::STT_SECTION) {
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|       Expected<section_iterator> SymSI = SI->getSection();
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|       if (!SymSI)
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|         return SymSI.takeError();
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|       const typename ELFT::Shdr *SymSec =
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|           Obj->getSection((*SymSI)->getRawDataRefImpl());
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|       auto SecName = EF.getSectionName(SymSec);
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|       if (!SecName)
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|         return SecName.takeError();
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|       Fmt << *SecName;
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|     } else {
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|       Expected<StringRef> SymName = SI->getName();
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|       if (!SymName)
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|         return SymName.takeError();
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|       if (Demangle)
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|         Fmt << demangle(std::string(*SymName));
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|       else
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|         Fmt << *SymName;
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|     }
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|   } else {
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|     Fmt << "*ABS*";
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|   }
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|   if (Addend != 0) {
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|       Fmt << (Addend < 0
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|           ? "-"
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|           : "+") << format("0x%" PRIx64,
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|                           (Addend < 0 ? -(uint64_t)Addend : (uint64_t)Addend));
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|   }
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|   Fmt.flush();
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|   Result.append(FmtBuf.begin(), FmtBuf.end());
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|   return Error::success();
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| }
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| 
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| Error getELFRelocationValueString(const ELFObjectFileBase *Obj,
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|                                   const RelocationRef &Rel,
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|                                   SmallVectorImpl<char> &Result) {
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|   if (auto *ELF32LE = dyn_cast<ELF32LEObjectFile>(Obj))
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|     return getRelocationValueString(ELF32LE, Rel, Result);
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|   if (auto *ELF64LE = dyn_cast<ELF64LEObjectFile>(Obj))
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|     return getRelocationValueString(ELF64LE, Rel, Result);
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|   if (auto *ELF32BE = dyn_cast<ELF32BEObjectFile>(Obj))
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|     return getRelocationValueString(ELF32BE, Rel, Result);
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|   auto *ELF64BE = cast<ELF64BEObjectFile>(Obj);
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|   return getRelocationValueString(ELF64BE, Rel, Result);
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| }
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| 
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| template <class ELFT>
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| static uint64_t getSectionLMA(const ELFFile<ELFT> *Obj,
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|                               const object::ELFSectionRef &Sec) {
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|   auto PhdrRangeOrErr = Obj->program_headers();
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|   if (!PhdrRangeOrErr)
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|     report_fatal_error(toString(PhdrRangeOrErr.takeError()));
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| 
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|   // Search for a PT_LOAD segment containing the requested section. Use this
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|   // segment's p_addr to calculate the section's LMA.
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|   for (const typename ELFT::Phdr &Phdr : *PhdrRangeOrErr)
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|     if ((Phdr.p_type == ELF::PT_LOAD) && (Phdr.p_vaddr <= Sec.getAddress()) &&
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|         (Phdr.p_vaddr + Phdr.p_memsz > Sec.getAddress()))
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|       return Sec.getAddress() - Phdr.p_vaddr + Phdr.p_paddr;
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| 
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|   // Return section's VMA if it isn't in a PT_LOAD segment.
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|   return Sec.getAddress();
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| }
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| 
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| uint64_t getELFSectionLMA(const object::ELFSectionRef &Sec) {
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|   if (const auto *ELFObj = dyn_cast<ELF32LEObjectFile>(Sec.getObject()))
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|     return getSectionLMA(ELFObj->getELFFile(), Sec);
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|   else if (const auto *ELFObj = dyn_cast<ELF32BEObjectFile>(Sec.getObject()))
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|     return getSectionLMA(ELFObj->getELFFile(), Sec);
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|   else if (const auto *ELFObj = dyn_cast<ELF64LEObjectFile>(Sec.getObject()))
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|     return getSectionLMA(ELFObj->getELFFile(), Sec);
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|   const auto *ELFObj = cast<ELF64BEObjectFile>(Sec.getObject());
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|   return getSectionLMA(ELFObj->getELFFile(), Sec);
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| }
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| 
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| template <class ELFT>
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| void printDynamicSection(const ELFFile<ELFT> *Elf, StringRef Filename) {
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|   ArrayRef<typename ELFT::Dyn> DynamicEntries =
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|       unwrapOrError(Elf->dynamicEntries(), Filename);
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| 
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|   // Find the maximum tag name length to format the value column properly.
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|   size_t MaxLen = 0;
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|   for (const typename ELFT::Dyn &Dyn : DynamicEntries)
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|     MaxLen = std::max(MaxLen, Elf->getDynamicTagAsString(Dyn.d_tag).size());
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|   std::string TagFmt = "  %-" + std::to_string(MaxLen) + "s ";
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| 
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|   outs() << "Dynamic Section:\n";
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|   for (const typename ELFT::Dyn &Dyn : DynamicEntries) {
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|     if (Dyn.d_tag == ELF::DT_NULL)
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|       continue;
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| 
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|     std::string Str = Elf->getDynamicTagAsString(Dyn.d_tag);
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|     outs() << format(TagFmt.c_str(), Str.c_str());
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| 
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|     const char *Fmt =
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|         ELFT::Is64Bits ? "0x%016" PRIx64 "\n" : "0x%08" PRIx64 "\n";
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|     if (Dyn.d_tag == ELF::DT_NEEDED || Dyn.d_tag == ELF::DT_RPATH ||
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|         Dyn.d_tag == ELF::DT_RUNPATH || Dyn.d_tag == ELF::DT_SONAME ||
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|         Dyn.d_tag == ELF::DT_AUXILIARY || Dyn.d_tag == ELF::DT_FILTER) {
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|       Expected<StringRef> StrTabOrErr = getDynamicStrTab(Elf);
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|       if (StrTabOrErr) {
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|         const char *Data = StrTabOrErr.get().data();
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|         outs() << (Data + Dyn.d_un.d_val) << "\n";
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|         continue;
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|       }
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|       reportWarning(toString(StrTabOrErr.takeError()), Filename);
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|       consumeError(StrTabOrErr.takeError());
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|     }
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|     outs() << format(Fmt, (uint64_t)Dyn.d_un.d_val);
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|   }
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| }
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| 
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| template <class ELFT> void printProgramHeaders(const ELFFile<ELFT> *o) {
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|   outs() << "Program Header:\n";
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|   auto ProgramHeaderOrError = o->program_headers();
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|   if (!ProgramHeaderOrError)
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|     report_fatal_error(toString(ProgramHeaderOrError.takeError()));
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|   for (const typename ELFT::Phdr &Phdr : *ProgramHeaderOrError) {
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|     switch (Phdr.p_type) {
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|     case ELF::PT_DYNAMIC:
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|       outs() << " DYNAMIC ";
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|       break;
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|     case ELF::PT_GNU_EH_FRAME:
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|       outs() << "EH_FRAME ";
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|       break;
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|     case ELF::PT_GNU_RELRO:
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|       outs() << "   RELRO ";
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|       break;
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|     case ELF::PT_GNU_PROPERTY:
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|       outs() << "   PROPERTY ";
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|       break;
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|     case ELF::PT_GNU_STACK:
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|       outs() << "   STACK ";
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|       break;
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|     case ELF::PT_INTERP:
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|       outs() << "  INTERP ";
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|       break;
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|     case ELF::PT_LOAD:
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|       outs() << "    LOAD ";
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|       break;
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|     case ELF::PT_NOTE:
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|       outs() << "    NOTE ";
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|       break;
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|     case ELF::PT_OPENBSD_BOOTDATA:
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|       outs() << "    OPENBSD_BOOTDATA ";
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|       break;
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|     case ELF::PT_OPENBSD_RANDOMIZE:
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|       outs() << "    OPENBSD_RANDOMIZE ";
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|       break;
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|     case ELF::PT_OPENBSD_WXNEEDED:
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|       outs() << "    OPENBSD_WXNEEDED ";
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|       break;
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|     case ELF::PT_PHDR:
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|       outs() << "    PHDR ";
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|       break;
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|     case ELF::PT_TLS:
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|       outs() << "    TLS ";
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|       break;
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|     default:
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|       outs() << " UNKNOWN ";
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|     }
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| 
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|     const char *Fmt = ELFT::Is64Bits ? "0x%016" PRIx64 " " : "0x%08" PRIx64 " ";
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| 
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|     outs() << "off    " << format(Fmt, (uint64_t)Phdr.p_offset) << "vaddr "
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|            << format(Fmt, (uint64_t)Phdr.p_vaddr) << "paddr "
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|            << format(Fmt, (uint64_t)Phdr.p_paddr)
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|            << format("align 2**%u\n",
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|                      countTrailingZeros<uint64_t>(Phdr.p_align))
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|            << "         filesz " << format(Fmt, (uint64_t)Phdr.p_filesz)
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|            << "memsz " << format(Fmt, (uint64_t)Phdr.p_memsz) << "flags "
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|            << ((Phdr.p_flags & ELF::PF_R) ? "r" : "-")
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|            << ((Phdr.p_flags & ELF::PF_W) ? "w" : "-")
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|            << ((Phdr.p_flags & ELF::PF_X) ? "x" : "-") << "\n";
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|   }
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|   outs() << "\n";
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| }
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| 
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| template <class ELFT>
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| void printSymbolVersionDependency(ArrayRef<uint8_t> Contents,
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|                                   StringRef StrTab) {
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|   outs() << "Version References:\n";
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| 
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|   const uint8_t *Buf = Contents.data();
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|   while (Buf) {
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|     auto *Verneed = reinterpret_cast<const typename ELFT::Verneed *>(Buf);
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|     outs() << "  required from "
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|            << StringRef(StrTab.drop_front(Verneed->vn_file).data()) << ":\n";
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| 
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|     const uint8_t *BufAux = Buf + Verneed->vn_aux;
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|     while (BufAux) {
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|       auto *Vernaux = reinterpret_cast<const typename ELFT::Vernaux *>(BufAux);
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|       outs() << "    "
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|              << format("0x%08" PRIx32 " ", (uint32_t)Vernaux->vna_hash)
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|              << format("0x%02" PRIx16 " ", (uint16_t)Vernaux->vna_flags)
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|              << format("%02" PRIu16 " ", (uint16_t)Vernaux->vna_other)
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|              << StringRef(StrTab.drop_front(Vernaux->vna_name).data()) << '\n';
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|       BufAux = Vernaux->vna_next ? BufAux + Vernaux->vna_next : nullptr;
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|     }
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|     Buf = Verneed->vn_next ? Buf + Verneed->vn_next : nullptr;
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|   }
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| }
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| 
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| template <class ELFT>
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| void printSymbolVersionDefinition(const typename ELFT::Shdr &Shdr,
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|                                   ArrayRef<uint8_t> Contents,
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|                                   StringRef StrTab) {
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|   outs() << "Version definitions:\n";
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| 
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|   const uint8_t *Buf = Contents.data();
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|   uint32_t VerdefIndex = 1;
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|   // sh_info contains the number of entries in the SHT_GNU_verdef section. To
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|   // make the index column have consistent width, we should insert blank spaces
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|   // according to sh_info.
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|   uint16_t VerdefIndexWidth = std::to_string(Shdr.sh_info).size();
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|   while (Buf) {
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|     auto *Verdef = reinterpret_cast<const typename ELFT::Verdef *>(Buf);
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|     outs() << format_decimal(VerdefIndex++, VerdefIndexWidth) << " "
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|            << format("0x%02" PRIx16 " ", (uint16_t)Verdef->vd_flags)
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|            << format("0x%08" PRIx32 " ", (uint32_t)Verdef->vd_hash);
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| 
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|     const uint8_t *BufAux = Buf + Verdef->vd_aux;
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|     uint16_t VerdauxIndex = 0;
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|     while (BufAux) {
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|       auto *Verdaux = reinterpret_cast<const typename ELFT::Verdaux *>(BufAux);
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|       if (VerdauxIndex)
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|         outs() << std::string(VerdefIndexWidth + 17, ' ');
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|       outs() << StringRef(StrTab.drop_front(Verdaux->vda_name).data()) << '\n';
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|       BufAux = Verdaux->vda_next ? BufAux + Verdaux->vda_next : nullptr;
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|       ++VerdauxIndex;
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|     }
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|     Buf = Verdef->vd_next ? Buf + Verdef->vd_next : nullptr;
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|   }
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| }
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| 
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| template <class ELFT>
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| void printSymbolVersionInfo(const ELFFile<ELFT> *Elf, StringRef FileName) {
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|   ArrayRef<typename ELFT::Shdr> Sections =
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|       unwrapOrError(Elf->sections(), FileName);
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|   for (const typename ELFT::Shdr &Shdr : Sections) {
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|     if (Shdr.sh_type != ELF::SHT_GNU_verneed &&
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|         Shdr.sh_type != ELF::SHT_GNU_verdef)
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|       continue;
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| 
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|     ArrayRef<uint8_t> Contents =
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|         unwrapOrError(Elf->getSectionContents(&Shdr), FileName);
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|     const typename ELFT::Shdr *StrTabSec =
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|         unwrapOrError(Elf->getSection(Shdr.sh_link), FileName);
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|     StringRef StrTab = unwrapOrError(Elf->getStringTable(StrTabSec), FileName);
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| 
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|     if (Shdr.sh_type == ELF::SHT_GNU_verneed)
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|       printSymbolVersionDependency<ELFT>(Contents, StrTab);
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|     else
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|       printSymbolVersionDefinition<ELFT>(Shdr, Contents, StrTab);
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|   }
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| }
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| 
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| void printELFFileHeader(const object::ObjectFile *Obj) {
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|   if (const auto *ELFObj = dyn_cast<ELF32LEObjectFile>(Obj))
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|     printProgramHeaders(ELFObj->getELFFile());
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|   else if (const auto *ELFObj = dyn_cast<ELF32BEObjectFile>(Obj))
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|     printProgramHeaders(ELFObj->getELFFile());
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|   else if (const auto *ELFObj = dyn_cast<ELF64LEObjectFile>(Obj))
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|     printProgramHeaders(ELFObj->getELFFile());
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|   else if (const auto *ELFObj = dyn_cast<ELF64BEObjectFile>(Obj))
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|     printProgramHeaders(ELFObj->getELFFile());
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| }
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| 
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| void printELFDynamicSection(const object::ObjectFile *Obj) {
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|   if (const auto *ELFObj = dyn_cast<ELF32LEObjectFile>(Obj))
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|     printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
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|   else if (const auto *ELFObj = dyn_cast<ELF32BEObjectFile>(Obj))
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|     printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
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|   else if (const auto *ELFObj = dyn_cast<ELF64LEObjectFile>(Obj))
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|     printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
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|   else if (const auto *ELFObj = dyn_cast<ELF64BEObjectFile>(Obj))
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|     printDynamicSection(ELFObj->getELFFile(), Obj->getFileName());
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| }
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| 
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| void printELFSymbolVersionInfo(const object::ObjectFile *Obj) {
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|   if (const auto *ELFObj = dyn_cast<ELF32LEObjectFile>(Obj))
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|     printSymbolVersionInfo(ELFObj->getELFFile(), Obj->getFileName());
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|   else if (const auto *ELFObj = dyn_cast<ELF32BEObjectFile>(Obj))
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|     printSymbolVersionInfo(ELFObj->getELFFile(), Obj->getFileName());
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|   else if (const auto *ELFObj = dyn_cast<ELF64LEObjectFile>(Obj))
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|     printSymbolVersionInfo(ELFObj->getELFFile(), Obj->getFileName());
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|   else if (const auto *ELFObj = dyn_cast<ELF64BEObjectFile>(Obj))
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|     printSymbolVersionInfo(ELFObj->getELFFile(), Obj->getFileName());
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| }
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| } // namespace llvm
 |