[llvm-pdbutil] Fix a crash due to Expected not checked before destruction

[aganea]

LGTM with a comment:

llvm/tools/llvm-pdbutil/DumpOutputStyle.cpp

492

I think it could help future code readers - if the type of "Sections" was made explicit:

auto SectionsOrErr = getSectionNames(getPdb());
if (!SectionsOrErr)
  return SectionsOrErr.takeError();
ArrayRef<std::string> Sections = *SectionsOrErr;

dumpSectionContrib(P, Desc.getSectionContrib(), Sections, 0);

or just

Expected<std::vector<std::string>> Sections = getSectionNames(getPdb());

1846–1850

Same here.

llvm/tools/llvm-pdbutil/DumpOutputStyle.cpp

return make_error<StringError>(
         inconvertibleErrorCode());
 
   uint32_t NumHeaders = Stream->getLength() / sizeof(object::coff_section);
   BinaryStreamReader Reader(*Stream);
   cantFail(Reader.readArray(Headers, NumHeaders));
   return std::make_pair(std::move(Stream), Headers);
 }
 
-static std::vector<std::string> getSectionNames(PDBFile &File) {
+static Expected<std::vector<std::string>> getSectionNames(PDBFile &File) {
   auto ExpectedHeaders = loadSectionHeaders(File, DbgHeaderType::SectionHdr);
   if (!ExpectedHeaders)
-    return {};
+    return ExpectedHeaders.takeError();
 
   std::unique_ptr<MappedBlockStream> Stream;
   ArrayRef<object::coff_section> Headers;
   std::tie(Stream, Headers) = std::move(*ExpectedHeaders);
   std::vector<std::string> Names;
   for (const auto &H : Headers)
     Names.push_back(H.Name);
   return Names;
Error DumpOutputStyle::dumpModules() {
   DbiStream &Stream = *StreamOrErr;
 
   const DbiModuleList &Modules = Stream.modules();
   return iterateSymbolGroups(
       File, PrintScope{P, 11},
       [&](uint32_t Modi, const SymbolGroup &Strings) -> Error {
         auto Desc = Modules.getModuleDescriptor(Modi);
         if (opts::dump::DumpSectionContribs) {
-          std::vector<std::string> Sections = getSectionNames(getPdb());
+          auto SectionsOrErr = getSectionNames(getPdb());
+          if (!SectionsOrErr)
+            return SectionsOrErr.takeError();
+          ArrayRef<std::string> Sections = *SectionsOrErr;
           dumpSectionContrib(P, Desc.getSectionContrib(), Sections, 0);
         }
         P.formatLine("Obj: `{0}`: ", Desc.getObjFileName());
         P.formatLine("debug stream: {0}, # files: {1}, has ec info: {2}",
                      Desc.getModuleStreamIndex(), Desc.getNumberOfFiles(),
                      Desc.hasECInfo());
 
         auto PdbPathOrErr = Stream.getECName(Desc.getPdbFilePathNameIndex());
         if (!PdbPathOrErr)
public:
     }
 
   private:
     LinePrinter &P;
     uint32_t MaxNameLen;
     ArrayRef<std::string> Names;
   };
 
-  std::vector<std::string> Names = getSectionNames(getPdb());
-  Visitor V(P, makeArrayRef(Names));
+  auto NamesOrErr = getSectionNames(getPdb());
+  if (!NamesOrErr)
+    return NamesOrErr.takeError();
+  ArrayRef<std::string> Names = *NamesOrErr;
+  Visitor V(P, Names);
   Dbi.visitSectionContributions(V);
   return Error::success();
 }
 
 Error DumpOutputStyle::dumpSectionMap() {
   printHeader(P, "Section Map");
 
   if (File.isObj()) {