[clangd] Track performance of IncludeCleaner

[kadircet]

clang-tools-extra/clangd/IncludeCleaner.cpp

275

this doesn't look interesting on its own, as it doesn't perform much magic. maybe just drop?

283

i believe this is the function that deserves a trace the most, as it is alive throughout the whole interaction and will reflect full latency.

[kbobyrev]

Address review comments.

[kadircet]

oops forgot to LGTM, thanks!

clang-tools-extra/clangd/IncludeCleaner.cpp

 // for umbrella headers and Standard Library headers, don't warn about them.
 bool mayConsiderUnused(const Inclusion *Inc) {
   return Inc->Written.front() != '<';
 }
 
 } // namespace
 
 ReferencedLocations findReferencedLocations(ParsedAST &AST) {
+  trace::Span Tracer("IncludeCleaner::findReferencedLocations");
   ReferencedLocations Result;
   ReferencedLocationCrawler Crawler(Result);
   Crawler.TraverseAST(AST.getASTContext());
   findReferencedMacros(AST, Result);
   return Result;
 }
 
 llvm::DenseSet<FileID>
for (auto It = Sorted.begin(); It < Sorted.end();) {
     while (It != Sorted.end() && SM.isInFileID(*It, FID));
   }
   return std::move(Result.Files);
 }
 
 std::vector<const Inclusion *>
 getUnused(const IncludeStructure &Includes,
           const llvm::DenseSet<IncludeStructure::HeaderID> &ReferencedFiles) {
+  trace::Span Tracer("IncludeCleaner::getUnused");
   std::vector<const Inclusion *> Unused;
   for (const Inclusion &MFI : Includes.MainFileIncludes) {
     // FIXME: Skip includes that are not self-contained.
     if (!MFI.HeaderID) {
       elog("File {0} not found.", MFI.Written);
       continue;
     }
     auto IncludeID = static_cast<IncludeStructure::HeaderID>(*MFI.HeaderID);
static bool isSpecialBuffer(FileID FID, const SourceManager &SM) {
   return FI.getName().startswith("<");
 }
 #endif
 
 llvm::DenseSet<IncludeStructure::HeaderID>
 translateToHeaderIDs(const llvm::DenseSet<FileID> &Files,
                      const IncludeStructure &Includes,
                      const SourceManager &SM) {
+  trace::Span Tracer("IncludeCleaner::translateToHeaderIDs");
   llvm::DenseSet<IncludeStructure::HeaderID> TranslatedHeaderIDs;
   TranslatedHeaderIDs.reserve(Files.size());
   for (FileID FID : Files) {
     const FileEntry *FE = SM.getFileEntryForID(FID);
     if (!FE) {
       assert(isSpecialBuffer(FID, SM));
       continue;
     }
     const auto File = Includes.getID(FE);
     assert(File);
     TranslatedHeaderIDs.insert(*File);
   }
   return TranslatedHeaderIDs;
 }
 
 std::vector<const Inclusion *> computeUnusedIncludes(ParsedAST &AST) {
   const auto &SM = AST.getSourceManager();
 
   auto Refs = findReferencedLocations(AST);
   auto ReferencedFiles = translateToHeaderIDs(findReferencedFiles(Refs, SM),
                                               AST.getIncludeStructure(), SM);
   return getUnused(AST.getIncludeStructure(), ReferencedFiles);
 }
 
 std::vector<Diag> issueUnusedIncludesDiagnostics(ParsedAST &AST,
                                                  llvm::StringRef Code) {
+  trace::Span Tracer("IncludeCleaner::issueUnusedIncludesDiagnostics");
   const Config &Cfg = Config::current();
   if (Cfg.Diagnostics.UnusedIncludes != Config::UnusedIncludesPolicy::Strict ||
       Cfg.Diagnostics.SuppressAll ||
       Cfg.Diagnostics.Suppress.contains("unused-includes"))
     return {};
   std::vector<Diag> Result;
   std::string FileName =
       AST.getSourceManager()