[llvm/Object] Reimplment basic_symbol_iterator in TapiFile

[JDevlieghere]

Summary

Use indices into the Symbols vector instead of dereferencing std::vector::end().

NFC modulo the Windows failure: http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win/builds/24024

[cishida]

Thanks for fixing this! one nit but LGTM

llvm/lib/Object/TapiFile.cpp

81–83

nit: maybe add a message to notify an out of bounds access?

88–89

same here

llvm/lib/Object/TapiFile.cpp

case SymbolKind::ObjectiveCInstanceVariable:
                            getFlags(Symbol));
       break;
     }
   }
 }
 
 TapiFile::~TapiFile() = default;
 
-void TapiFile::moveSymbolNext(DataRefImpl &DRI) const {
-  const auto *Sym = reinterpret_cast<const Symbol *>(DRI.p);
-  DRI.p = reinterpret_cast<uintptr_t>(++Sym);
-}
+void TapiFile::moveSymbolNext(DataRefImpl &DRI) const { DRI.d.a++; }
 
 Error TapiFile::printSymbolName(raw_ostream &OS, DataRefImpl DRI) const {
-  const auto *Sym = reinterpret_cast<const Symbol *>(DRI.p);
-  OS << Sym->Prefix << Sym->Name;
+  assert(DRI.d.a < Symbols.size() && "Attempt to access symbol out of bounds");
+  const Symbol &Sym = Symbols[DRI.d.a];
+  OS << Sym.Prefix << Sym.Name;
   return Error::success();
 }
 
 Expected<uint32_t> TapiFile::getSymbolFlags(DataRefImpl DRI) const {
-  const auto *Sym = reinterpret_cast<const Symbol *>(DRI.p);
-  return Sym->Flags;
+  assert(DRI.d.a < Symbols.size() && "Attempt to access symbol out of bounds");
+  return Symbols[DRI.d.a].Flags;
 }
 
 basic_symbol_iterator TapiFile::symbol_begin() const {
   DataRefImpl DRI;
-  DRI.p = reinterpret_cast<uintptr_t>(&*Symbols.begin());
+  DRI.d.a = 0;
   return BasicSymbolRef{DRI, this};
 }
 
 basic_symbol_iterator TapiFile::symbol_end() const {
   DataRefImpl DRI;
-  DRI.p = reinterpret_cast<uintptr_t>(&*Symbols.end());
+  DRI.d.a = Symbols.size();
   return BasicSymbolRef{DRI, this};
 }