Lambda_solution.cpp

template <class ELFT>
Expected<const uint8_t *> getDataFromDynsym(
    const ELFFile<ELFT> &ElfFile, uint64_t DynAddr, StringRef Name,
    function_ref<Expected<const uint8_t *>(const typename ELFT::Shdr &,
                                           const typename ELFT::ShdrRange &)>
        OnFound) {
  using Elf_Shdr_Range = typename ELFT::ShdrRange;
  using Elf_Shdr = typename ELFT::Shdr;

  Expected<Elf_Shdr_Range> Shdrs = ElfFile.sections();
  if (!Shdrs)
    return Shdrs.takeError();

  if (Shdrs.get().size()) {
    for (const Elf_Shdr &Sec : *Shdrs) {
      if (Sec.sh_type == ELF::SHT_DYNSYM) {
        // If multiple .dynsym are present, use the first one.
        // This behavior aligns with llvm::object::ELFFile::getDynSymtabSize().
        return OnFound(Sec, *Shdrs);
      }
    }
  } // Fallback to use offsets from .dynamic as .dynsym was not found.
  Expected<const uint8_t *> PtrOrErr = ElfFile.toMappedAddr(DynAddr);
  if (!PtrOrErr)
    return appendToError(
        PtrOrErr.takeError(),
        StringRef("when locating " + Name.str() + " section contents"));
  return *PtrOrErr;
}

template <class ELFT>
static Expected<const uint8_t *> getDynSymPtr(const ELFFile<ELFT> &ElfFile,
                                              const DynamicEntries &DynEnt) {
  return getDataFromDynsym(ElfFile, DynEnt.DynSymAddr, ".dynsym",
                           [&ElfFile](const typename ELFT::Shdr &Sec,
                                      const typename ELFT::ShdrRange &Shdrs) {
                             return ElfFile.base() + Sec.sh_offset;
                           });
}

template <class ELFT>
static Expected<StringRef> getDynStr(const ELFFile<ELFT> &ElfFile,
                                     const DynamicEntries &DynEnt) {
  Expected<const uint8_t *> ResultOrErr = getDataFromDynsym(
      ElfFile, DynEnt.StrTabAddr, ".dynstr",
      [&ElfFile](
          const typename ELFT::Shdr &Sec,
          const typename ELFT::ShdrRange &Shdrs) -> Expected<const uint8_t *> {
        Expected<StringRef> DynStrRef =
            ElfFile.getStringTableForSymtab(Sec, Shdrs);
        if (!DynStrRef)
          return DynStrRef.takeError();
        return DynStrRef.get().bytes_begin();
      });
  if (!ResultOrErr)
    return ResultOrErr.takeError();
  return StringRef(reinterpret_cast<const char *>(*ResultOrErr),
                   DynEnt.StrSize);
}