std::unique_ptr<clang::ASTConsumer>
 CreateASTConsumer(clang::CompilerInstance &CI, StringRef InFile) override {
   CI.setExternalSemaSource(SemaSource);
   SemaSource->setFilePath(InFile);
   SemaSource->setCompilerInstance(&CI);
   return llvm::make_unique<ASTConsumerManagerWrapper>(SymbolIndexMgr);
 }