[ELF] Pass LLDDwarfObj to readPubNamesAndTypes

[MaskRay]

Summary

We reorder the processing of .debug_gnu_pub{names,types} and other .gdb_index components, so as to save a static_cast.

[MaskRay]

No, I cannot do this as https://reviews.llvm.org/D54361 needs const std::vector<GdbIndexSection::CuEntry> &CUs which requires building DwarfContext.

ELF/SyntheticSections.cpp

for (std::unique_ptr<DWARFUnit> &Cu : Dwarf.compile_units()) {
     }
     ++CuIdx;
   }
   return Ret;
 }
 
 template <class ELFT>
 static std::vector<GdbIndexSection::NameTypeEntry>
-readPubNamesAndTypes(DWARFContext &Dwarf, uint32_t Idx) {
-  auto &Obj = static_cast<const LLDDwarfObj<ELFT> &>(Dwarf.getDWARFObj());
+readPubNamesAndTypes(LLDDwarfObj<ELFT> &Obj, uint32_t Idx) {
   const DWARFSection &PubNames = Obj.getGnuPubNamesSection();
   const DWARFSection &PubTypes = Obj.getGnuPubTypesSection();
 
   std::vector<GdbIndexSection::NameTypeEntry> Ret;
   for (const DWARFSection *Pub : {&PubNames, &PubTypes}) {
     DWARFDebugPubTable Table(Obj, *Pub, Config->IsLE, true);
     for (const DWARFDebugPubTable::Set &Set : Table.getData())
       for (const DWARFDebugPubTable::Entry &Ent : Set.Entries)
for (InputSectionBase *S : InputSections)
     if (S->Name == ".debug_gnu_pubnames" || S->Name == ".debug_gnu_pubtypes")
       S->Live = false;
 
   std::vector<GdbChunk> Chunks(Sections.size());
   std::vector<std::vector<NameTypeEntry>> NameTypes(Sections.size());
 
   parallelForEachN(0, Sections.size(), [&](size_t I) {
     ObjFile<ELFT> *File = Sections[I]->getFile<ELFT>();
-    DWARFContext Dwarf(make_unique<LLDDwarfObj<ELFT>>(File));
+    auto Obj = make_unique<LLDDwarfObj<ELFT>>(File);
+    NameTypes[I] = readPubNamesAndTypes<ELFT>(*Obj, I);
 
+    DWARFContext Dwarf(std::move(Obj));
     Chunks[I].Sec = Sections[I];
     Chunks[I].CompilationUnits = readCuList(Dwarf);
     Chunks[I].AddressAreas = readAddressAreas(Dwarf, Sections[I]);
-    NameTypes[I] = readPubNamesAndTypes<ELFT>(Dwarf, I);
   });
 
   auto *Ret = make<GdbIndexSection>();
   Ret->Chunks = std::move(Chunks);
   Ret->Symbols = createSymbols(NameTypes);
   Ret->initOutputSize();
   return Ret;
 }