C++ RelocationRef类代码示例

void COFFDumper::printRelocation(const SectionRef &Section,
                                 const RelocationRef &Reloc) {
  uint64_t Offset;
  uint64_t RelocType;
  SmallString<32> RelocName;
  StringRef SymbolName;
  StringRef Contents;
  if (error(Reloc.getOffset(Offset)))
    return;
  if (error(Reloc.getType(RelocType)))
    return;
  if (error(Reloc.getTypeName(RelocName)))
    return;
  symbol_iterator Symbol = Reloc.getSymbol();
  if (error(Symbol->getName(SymbolName)))
    return;
  if (error(Section.getContents(Contents)))
    return;

  if (opts::ExpandRelocs) {
    DictScope Group(W, "Relocation");
    W.printHex("Offset", Offset);
    W.printNumber("Type", RelocName, RelocType);
    W.printString("Symbol", SymbolName.size() > 0 ? SymbolName : "-");
  } else {
    raw_ostream& OS = W.startLine();
    OS << W.hex(Offset)
       << " " << RelocName
       << " " << (SymbolName.size() > 0 ? SymbolName : "-")
       << "\n";
  }
}

void COFFDumper::printRelocation(const SectionRef &Section,
                                 const RelocationRef &Reloc) {
  uint64_t Offset = Reloc.getOffset();
  uint64_t RelocType = Reloc.getType();
  SmallString<32> RelocName;
  StringRef SymbolName;
  Reloc.getTypeName(RelocName);
  symbol_iterator Symbol = Reloc.getSymbol();
  if (Symbol != Obj->symbol_end()) {
    ErrorOr<StringRef> SymbolNameOrErr = Symbol->getName();
    error(SymbolNameOrErr.getError());
    SymbolName = *SymbolNameOrErr;
  }

  if (opts::ExpandRelocs) {
    DictScope Group(W, "Relocation");
    W.printHex("Offset", Offset);
    W.printNumber("Type", RelocName, RelocType);
    W.printString("Symbol", SymbolName.empty() ? "-" : SymbolName);
  } else {
    raw_ostream& OS = W.startLine();
    OS << W.hex(Offset)
       << " " << RelocName
       << " " << (SymbolName.empty() ? "-" : SymbolName)
       << "\n";
  }
}

/// Given a relocation from __compact_unwind, consisting of the RelocationRef
/// and data being relocated, determine the best base Name and Addend to use for
/// display purposes.
///
/// 1. An Extern relocation will directly reference a symbol (and the data is
///    then already an addend), so use that.
/// 2. Otherwise the data is an offset in the object file's layout; try to find
//     a symbol before it in the same section, and use the offset from there.
/// 3. Finally, if all that fails, fall back to an offset from the start of the
///    referenced section.
static void findUnwindRelocNameAddend(const MachOObjectFile *Obj,
                                      std::map<uint64_t, SymbolRef> &Symbols,
                                      const RelocationRef &Reloc,
                                      uint64_t Addr,
                                      StringRef &Name, uint64_t &Addend) {
  if (Reloc.getSymbol() != Obj->symbol_end()) {
    Reloc.getSymbol()->getName(Name);
    Addend = Addr;
    return;
  }

  auto RE = Obj->getRelocation(Reloc.getRawDataRefImpl());
  SectionRef RelocSection = Obj->getRelocationSection(RE);

  uint64_t SectionAddr;
  RelocSection.getAddress(SectionAddr);

  auto Sym = Symbols.upper_bound(Addr);
  if (Sym == Symbols.begin()) {
    // The first symbol in the object is after this reference, the best we can
    // do is section-relative notation.
    RelocSection.getName(Name);
    Addend = Addr - SectionAddr;
    return;
  }

  // Go back one so that SymbolAddress <= Addr.
  --Sym;

  section_iterator SymSection = Obj->section_end();
  Sym->second.getSection(SymSection);
  if (RelocSection == *SymSection) {
    // There's a valid symbol in the same section before this reference.
    Sym->second.getName(Name);
    Addend = Addr - Sym->first;
    return;
  }

  // There is a symbol before this reference, but it's in a different
  // section. Probably not helpful to mention it, so use the section name.
  RelocSection.getName(Name);
  Addend = Addr - SectionAddr;
}

static std::error_code getRelocationValueString(const COFFObjectFile *Obj,
                                                const RelocationRef &Rel,
                                                SmallVectorImpl<char> &Result) {
  symbol_iterator SymI = Rel.getSymbol();
  StringRef SymName;
  if (std::error_code EC = SymI->getName(SymName))
    return EC;
  Result.append(SymName.begin(), SymName.end());
  return std::error_code();
}

void symbol_reference(const ELFObjectFile<T> &obj, const RelocationRef &rel, section_iterator sec, ogre_doc &s) {
    auto it = rel.getSymbol();
    if (it == prim::end_symbols(obj)) return;
    auto sym_elf = obj.getSymbol(it->getRawDataRefImpl());
    auto sec_offset = section_offset(obj, sec);
    auto off = prim::relocation_offset(rel) + sec_offset; // relocation file offset
    if (is_external_symbol(*sym_elf)) {
        if (auto name = prim::symbol_name(*it))
            s.entry("ref-external") << off << *name;
    } else {
        if (auto file_offset = symbol_file_offset(obj, *it))
            s.entry("ref-internal") << *file_offset << off;
    }
}

void RuntimeDyldMachO::processRelocationRef(unsigned SectionID,
                                            RelocationRef RelI,
                                            ObjectImage &Obj,
                                            ObjSectionToIDMap &ObjSectionToID,
                                            const SymbolTableMap &Symbols,
                                            StubMap &Stubs) {
  const ObjectFile *OF = Obj.getObjectFile();
  const MachOObjectFile *MachO = static_cast<const MachOObjectFile*>(OF);
  MachO::any_relocation_info RE= MachO->getRelocation(RelI.getRawDataRefImpl());

  uint32_t RelType = MachO->getAnyRelocationType(RE);

  // FIXME: Properly handle scattered relocations.
  //        For now, optimistically skip these: they can often be ignored, as
  //        the static linker will already have applied the relocation, and it
  //        only needs to be reapplied if symbols move relative to one another.
  //        Note: This will fail horribly where the relocations *do* need to be
  //        applied, but that was already the case.
  if (MachO->isRelocationScattered(RE))
    return;

  RelocationValueRef Value;
  SectionEntry &Section = Sections[SectionID];

  bool isExtern = MachO->getPlainRelocationExternal(RE);
  bool IsPCRel = MachO->getAnyRelocationPCRel(RE);
  unsigned Size = MachO->getAnyRelocationLength(RE);
  uint64_t Offset;
  RelI.getOffset(Offset);
  uint8_t *LocalAddress = Section.Address + Offset;
  unsigned NumBytes = 1 << Size;
  uint64_t Addend = 0;
  memcpy(&Addend, LocalAddress, NumBytes);

  if (isExtern) {
    // Obtain the symbol name which is referenced in the relocation
    symbol_iterator Symbol = RelI.getSymbol();
    StringRef TargetName;
    Symbol->getName(TargetName);
    // First search for the symbol in the local symbol table
    SymbolTableMap::const_iterator lsi = Symbols.find(TargetName.data());
    if (lsi != Symbols.end()) {
      Value.SectionID = lsi->second.first;
      Value.Addend = lsi->second.second + Addend;
    } else {
      // Search for the symbol in the global symbol table
      SymbolTableMap::const_iterator gsi = GlobalSymbolTable.find(TargetName.data());
      if (gsi != GlobalSymbolTable.end()) {
        Value.SectionID = gsi->second.first;
        Value.Addend = gsi->second.second + Addend;
      } else {
        Value.SymbolName = TargetName.data();
        Value.Addend = Addend;
      }
    }
  } else {
    SectionRef Sec = MachO->getRelocationSection(RE);
    bool IsCode = false;
    Sec.isText(IsCode);
    Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
    uint64_t Addr;
    Sec.getAddress(Addr);
    Value.Addend = Addend - Addr;
    if (IsPCRel)
      Value.Addend += Offset + NumBytes;
  }

  if (Arch == Triple::x86_64 && (RelType == MachO::X86_64_RELOC_GOT ||
                                 RelType == MachO::X86_64_RELOC_GOT_LOAD)) {
    assert(IsPCRel);
    assert(Size == 2);
    StubMap::const_iterator i = Stubs.find(Value);
    uint8_t *Addr;
    if (i != Stubs.end()) {
      Addr = Section.Address + i->second;
    } else {
      Stubs[Value] = Section.StubOffset;
      uint8_t *GOTEntry = Section.Address + Section.StubOffset;
      RelocationEntry RE(SectionID, Section.StubOffset,
                         MachO::X86_64_RELOC_UNSIGNED, 0, false, 3);
      if (Value.SymbolName)
        addRelocationForSymbol(RE, Value.SymbolName);
      else
        addRelocationForSection(RE, Value.SectionID);
      Section.StubOffset += 8;
      Addr = GOTEntry;
    }
    resolveRelocation(Section, Offset, (uint64_t)Addr,
                      MachO::X86_64_RELOC_UNSIGNED, Value.Addend, true, 2);
  } else if (Arch == Triple::arm &&
             (RelType & 0xf) == MachO::ARM_RELOC_BR24) {
    // This is an ARM branch relocation, need to use a stub function.

    //  Look up for existing stub.
    StubMap::const_iterator i = Stubs.find(Value);
    if (i != Stubs.end())
      resolveRelocation(Section, Offset,
                        (uint64_t)Section.Address + i->second,
                        RelType, 0, IsPCRel, Size);
    else {
//.........这里部分代码省略.........

bool relocAddressLess(RelocationRef a, RelocationRef b) {
  return a.getOffset() < b.getOffset();
}

bool llvm::RelocAddressLess(RelocationRef a, RelocationRef b) {
  uint64_t a_addr, b_addr;
  if (error(a.getOffset(a_addr))) return false;
  if (error(b.getOffset(b_addr))) return false;
  return a_addr < b_addr;
}

bool relocAddressLess(RelocationRef a, RelocationRef b) {
  uint64_t a_addr, b_addr;
  if (error(a.getOffset(a_addr))) exit(ReturnValue);
  if (error(b.getOffset(b_addr))) exit(ReturnValue);
  return a_addr < b_addr;
}

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) {
    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();
    const typename ELFT::Sym *Sym = Obj->getSymbol(SI->getRawDataRefImpl());
    if (Sym->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();
      if (Demangle)
        Fmt << demangle(*SymName);
      else
        Fmt << *SymName;
    }
  } else {
    Fmt << "*ABS*";
  }

  if (Addend != 0)
    Fmt << (Addend < 0 ? "" : "+") << Addend;
  Fmt.flush();
  Result.append(FmtBuf.begin(), FmtBuf.end());
  return Error::success();
}