[clang-tidy] Refactor IncludeInserter

[njames93]

Summary

Simplified how IncludeInserter is used in Checks by abstracting away the SourceManager and PPCallbacks inside the method registerPreprocessor.
Changed checks that use IncludeInserter to no longer use a std::unique_ptr, instead the IncludeInserter is just a member of the class thats initialized with an IncludeStyle.
Saving an unnecessary allocation.

This results in the removal of the field IncludeSorter::IncludeStyle from the checks, as its wrapped in the IncludeInserter.
No longer need to create an instance of the IncludeInserter in the registerPPCallbacks, now that method only needs to contain:

Inserter.registerPreprocessor(PP);

Also added a helper method to IncludeInserter called createMainFileInclusionInsertion, purely sugar but does better express intentions.

[aaron.ballman]

clang-tools-extra/clang-tidy/utils/IncludeInserter.cpp

55

I think it might be useful to add something like ; did you remember to call registerPreprocessor()? to the assertion message, as that seems like it would be the most likely issue if SourceMgr was null.

clang-tools-extra/clang-tidy/utils/IncludeInserter.h

59

retrived -> retrieved
ClangTidyOptios -> ClangTidyOptions

70

or if inclusion -> or if the inclusion

76

or if inclusion -> or if the inclusion

91

In-class initialize this to nullptr instead of leaving it indeterminate?

[njames93]

Address reviewer comments

[aaron.ballman]

LGTM!

clang-tools-extra/clang-tidy/abseil/StringFindStartswithCheck.h

public:
   StringFindStartswithCheck(StringRef Name, ClangTidyContext *Context);
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
 
 private:
-  std::unique_ptr<clang::tidy::utils::IncludeInserter> IncludeInserter;
   const std::vector<std::string> StringLikeClasses;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  utils::IncludeInserter IncludeInserter;
   const std::string AbseilStringsMatchHeader;
 };
 
 } // namespace abseil
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ABSEIL_STRINGFINDSTARTSWITHCHECK_H

clang-tools-extra/clang-tidy/abseil/StringFindStartswithCheck.cpp

 namespace tidy {
 namespace abseil {
 
 StringFindStartswithCheck::StringFindStartswithCheck(StringRef Name,
                                                      ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
       StringLikeClasses(utils::options::parseStringList(
           Options.get("StringLikeClasses", "::std::basic_string"))),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
+      IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
                                                utils::IncludeSorter::IS_LLVM)),
       AbseilStringsMatchHeader(
           Options.get("AbseilStringsMatchHeader", "absl/strings/match.h")) {}
 
 void StringFindStartswithCheck::registerMatchers(MatchFinder *Finder) {
   auto ZeroLiteral = integerLiteral(equals(0));
   auto StringClassMatcher = cxxRecordDecl(hasAnyName(SmallVector<StringRef, 4>(
       StringLikeClasses.begin(), StringLikeClasses.end())));
   auto StringType = hasUnqualifiedDesugaredType(
void StringFindStartswithCheck::check(const MatchFinder::MatchResult &Result) {
 
   Diagnostic << FixItHint::CreateReplacement(
       ComparisonExpr->getSourceRange(),
       (StartswithStr + "(" + HaystackExprCode + ", " + NeedleExprCode + ")")
           .str());
 
   // Create a preprocessor #include FixIt hint (CreateIncludeInsertion checks
   // whether this already exists).
-  Diagnostic << IncludeInserter->CreateIncludeInsertion(
+  Diagnostic << IncludeInserter.createIncludeInsertion(
       Source.getFileID(ComparisonExpr->getBeginLoc()), AbseilStringsMatchHeader,
       false);
 }
 
 void StringFindStartswithCheck::registerPPCallbacks(
     const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
-  IncludeInserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
-                                                              IncludeStyle);
-  PP->addPPCallbacks(IncludeInserter->CreatePPCallbacks());
+  IncludeInserter.registerPreprocessor(PP);
 }
 
 void StringFindStartswithCheck::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "StringLikeClasses",
                 utils::options::serializeStringList(StringLikeClasses));
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
   Options.store(Opts, "AbseilStringsMatchHeader", AbseilStringsMatchHeader);
 }
 
 } // namespace abseil
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clang-tidy/cppcoreguidelines/InitVariablesCheck.h

public:
   InitVariablesCheck(StringRef Name, ClangTidyContext *Context);
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  std::unique_ptr<clang::tidy::utils::IncludeInserter> IncludeInserter;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  utils::IncludeInserter IncludeInserter;
   const std::string MathHeader;
 };
 
 } // namespace cppcoreguidelines
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_CPPCOREGUIDELINES_INITVARIABLESCHECK_H

clang-tools-extra/clang-tidy/cppcoreguidelines/InitVariablesCheck.cpp

 
 namespace {
 AST_MATCHER(VarDecl, isLocalVarDecl) { return Node.isLocalVarDecl(); }
 } // namespace
 
 InitVariablesCheck::InitVariablesCheck(StringRef Name,
                                        ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
+      IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
                                                utils::IncludeSorter::IS_LLVM)),
       MathHeader(Options.get("MathHeader", "math.h")) {}
 
 void InitVariablesCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
   Options.store(Opts, "MathHeader", MathHeader);
 }
 
 void InitVariablesCheck::registerMatchers(MatchFinder *Finder) {
   std::string BadDecl = "badDecl";
   Finder->addMatcher(
       varDecl(unless(hasInitializer(anything())), unless(isInstantiated()),
               isLocalVarDecl(), unless(isStaticLocal()), isDefinition(),
               unless(hasParent(cxxCatchStmt())),
               optionally(hasParent(declStmt(hasParent(
                   cxxForRangeStmt(hasLoopVariable(varDecl().bind(BadDecl))))))),
               unless(equalsBoundNode(BadDecl)))
           .bind("vardecl"),
       this);
 }
 
 void InitVariablesCheck::registerPPCallbacks(const SourceManager &SM,
                                              Preprocessor *PP,
                                              Preprocessor *ModuleExpanderPP) {
-  IncludeInserter =
-      std::make_unique<utils::IncludeInserter>(SM, getLangOpts(), IncludeStyle);
-  PP->addPPCallbacks(IncludeInserter->CreatePPCallbacks());
+  IncludeInserter.registerPreprocessor(PP);
 }
 
 void InitVariablesCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *MatchedDecl = Result.Nodes.getNodeAs<VarDecl>("vardecl");
   const ASTContext &Context = *Result.Context;
   const SourceManager &Source = Context.getSourceManager();
 
   // We want to warn about cases where the type name
if (InitializationString) {
     auto Diagnostic =
         diag(MatchedDecl->getLocation(), "variable %0 is not initialized")
         << MatchedDecl
         << FixItHint::CreateInsertion(
                MatchedDecl->getLocation().getLocWithOffset(
                    MatchedDecl->getName().size()),
                InitializationString);
     if (AddMathInclude) {
-      Diagnostic << IncludeInserter->CreateIncludeInsertion(
+      Diagnostic << IncludeInserter.createIncludeInsertion(
           Source.getFileID(MatchedDecl->getBeginLoc()), MathHeader, false);
     }
   }
 }
 } // namespace cppcoreguidelines
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.h

 
 /// This checks that all array subscriptions on static arrays and std::arrays
 /// have a constant index and are within bounds
 ///
 /// For the user-facing documentation see:
 /// http://clang.llvm.org/extra/clang-tidy/checks/cppcoreguidelines-pro-bounds-constant-array-index.html
 class ProBoundsConstantArrayIndexCheck : public ClangTidyCheck {
   const std::string GslHeader;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
-  std::unique_ptr<utils::IncludeInserter> Inserter;
+  utils::IncludeInserter Inserter;
 
 public:
   ProBoundsConstantArrayIndexCheck(StringRef Name, ClangTidyContext *Context);
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
     return LangOpts.CPlusPlus;
   }
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override;

clang-tools-extra/clang-tidy/cppcoreguidelines/ProBoundsConstantArrayIndexCheck.cpp

 
 namespace clang {
 namespace tidy {
 namespace cppcoreguidelines {
 
 ProBoundsConstantArrayIndexCheck::ProBoundsConstantArrayIndexCheck(
     StringRef Name, ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context), GslHeader(Options.get("GslHeader", "")),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            utils::IncludeSorter::IS_LLVM)) {}
+      Inserter(Options.getLocalOrGlobal("IncludeStyle",
 
 void ProBoundsConstantArrayIndexCheck::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
   Options.store(Opts, "GslHeader", GslHeader);
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
 }
 
 void ProBoundsConstantArrayIndexCheck::registerPPCallbacks(
     const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
-  Inserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
-                                                       IncludeStyle);
-  PP->addPPCallbacks(Inserter->CreatePPCallbacks());
+  Inserter.registerPreprocessor(PP);
 }
 
 void ProBoundsConstantArrayIndexCheck::registerMatchers(MatchFinder *Finder) {
   // Note: if a struct contains an array member, the compiler-generated
   // constructor has an arraySubscriptExpr.
   Finder->addMatcher(
       arraySubscriptExpr(
           hasBase(ignoringImpCasts(hasType(constantArrayType().bind("type")))),
auto Diag = diag(Matched->getExprLoc(),
                      "instead");
     if (!GslHeader.empty()) {
       Diag << FixItHint::CreateInsertion(BaseRange.getBegin(), "gsl::at(")
            << FixItHint::CreateReplacement(
                   SourceRange(BaseRange.getEnd().getLocWithOffset(1),
                               IndexRange.getBegin().getLocWithOffset(-1)),
                   ", ")
            << FixItHint::CreateReplacement(Matched->getEndLoc(), ")")
-           << Inserter->CreateIncludeInsertion(
-                  Result.SourceManager->getMainFileID(), GslHeader,
+           << Inserter.createMainFileIncludeInsertion(GslHeader,
                                                       /*IsAngled=*/false);
     }
     return;
   }
 
   const auto *StdArrayDecl =
       Result.Nodes.getNodeAs<ClassTemplateSpecializationDecl>("type");
 
   // For static arrays, this is handled in clang-diagnostic-array-bounds.

clang-tools-extra/clang-tidy/modernize/MakeSmartPtrCheck.h

protected:
   virtual SmartPtrTypeMatcher getSmartPointerTypeMatcher() const = 0;
 
   /// Returns whether the C++ version is compatible with current check.
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override;
 
   static const char PointerType[];
 
 private:
-  std::unique_ptr<utils::IncludeInserter> Inserter;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  utils::IncludeInserter Inserter;
   const std::string MakeSmartPtrFunctionHeader;
   const std::string MakeSmartPtrFunctionName;
   const bool IgnoreMacros;
 
   void checkConstruct(SourceManager &SM, ASTContext *Ctx,
                       const CXXConstructExpr *Construct, const QualType *Type,
                       const CXXNewExpr *New);
   void checkReset(SourceManager &SM, ASTContext *Ctx,

clang-tools-extra/clang-tidy/modernize/MakeSmartPtrCheck.cpp

 
 } // namespace
 
 const char MakeSmartPtrCheck::PointerType[] = "pointerType";
 
 MakeSmartPtrCheck::MakeSmartPtrCheck(StringRef Name, ClangTidyContext *Context,
                                      StringRef MakeSmartPtrFunctionName)
     : ClangTidyCheck(Name, Context),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            utils::IncludeSorter::IS_LLVM)),
+      Inserter(Options.getLocalOrGlobal("IncludeStyle",
       MakeSmartPtrFunctionHeader(
           Options.get("MakeSmartPtrFunctionHeader", StdMemoryHeader)),
       MakeSmartPtrFunctionName(
           Options.get("MakeSmartPtrFunction", MakeSmartPtrFunctionName)),
       IgnoreMacros(Options.getLocalOrGlobal("IgnoreMacros", true)) {}
 
 void MakeSmartPtrCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
   Options.store(Opts, "MakeSmartPtrFunctionHeader", MakeSmartPtrFunctionHeader);
   Options.store(Opts, "MakeSmartPtrFunction", MakeSmartPtrFunctionName);
   Options.store(Opts, "IgnoreMacros", IgnoreMacros);
 }
 
 bool MakeSmartPtrCheck::isLanguageVersionSupported(
     const LangOptions &LangOpts) const {
   return LangOpts.CPlusPlus11;
 }
 
 void MakeSmartPtrCheck::registerPPCallbacks(const SourceManager &SM,
                                             Preprocessor *PP,
                                             Preprocessor *ModuleExpanderPP) {
-    Inserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
-                                                         IncludeStyle);
-    PP->addPPCallbacks(Inserter->CreatePPCallbacks());
+  Inserter.registerPreprocessor(PP);
 }
 
 void MakeSmartPtrCheck::registerMatchers(ast_matchers::MatchFinder *Finder) {
   // Calling make_smart_ptr from within a member function of a type with a
   // private or protected constructor would be ill-formed.
   auto CanCallCtor = unless(has(ignoringImpCasts(
       cxxConstructExpr(hasDeclaration(decl(unless(isPublic())))))));
 
bool MakeSmartPtrCheck::replaceNew(DiagnosticBuilder &Diag,
   }
   return true;
 }
 
 void MakeSmartPtrCheck::insertHeader(DiagnosticBuilder &Diag, FileID FD) {
   if (MakeSmartPtrFunctionHeader.empty()) {
     return;
   }
-  Diag << Inserter->CreateIncludeInsertion(
+  Diag << Inserter.createIncludeInsertion(
       FD, MakeSmartPtrFunctionHeader,
       /*IsAngled=*/MakeSmartPtrFunctionHeader == StdMemoryHeader);
 }
 
 } // namespace modernize
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clang-tidy/modernize/PassByValueCheck.h

public:
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  std::unique_ptr<utils::IncludeInserter> Inserter;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  utils::IncludeInserter Inserter;
   const bool ValuesOnly;
 };
 
 } // namespace modernize
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_PASS_BY_VALUE_H

clang-tools-extra/clang-tidy/modernize/PassByValueCheck.cpp

collectParamDecls(const CXXConstructorDecl *Ctor,
 
   for (const FunctionDecl *Redecl : Ctor->redecls())
     Results.push_back(Redecl->getParamDecl(ParamIdx));
   return Results;
 }
 
 PassByValueCheck::PassByValueCheck(StringRef Name, ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            utils::IncludeSorter::IS_LLVM)),
+      Inserter(Options.getLocalOrGlobal("IncludeStyle",
       ValuesOnly(Options.get("ValuesOnly", false)) {}
 
 void PassByValueCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
   Options.store(Opts, "ValuesOnly", ValuesOnly);
 }
 
 void PassByValueCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(
       traverse(
           ast_type_traits::TK_AsIs,
           cxxConstructorDecl(
Finder->addMatcher(
                       .bind("Initializer")))
               .bind("Ctor")),
       this);
 }
 
 void PassByValueCheck::registerPPCallbacks(const SourceManager &SM,
                                            Preprocessor *PP,
                                            Preprocessor *ModuleExpanderPP) {
-    Inserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
-                                                         IncludeStyle);
-    PP->addPPCallbacks(Inserter->CreatePPCallbacks());
+  Inserter.registerPreprocessor(PP);
 }
 
 void PassByValueCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *Ctor = Result.Nodes.getNodeAs<CXXConstructorDecl>("Ctor");
   const auto *ParamDecl = Result.Nodes.getNodeAs<ParmVarDecl>("Param");
   const auto *Initializer =
       Result.Nodes.getNodeAs<CXXCtorInitializer>("Initializer");
   SourceManager &SM = *Result.SourceManager;
for (const ParmVarDecl *ParmDecl : collectParamDecls(Ctor, ParamDecl)) {
     ValueStr += ' ';
     Diag << FixItHint::CreateReplacement(TypeRange, ValueStr);
   }
 
   // Use std::move in the initialization list.
   Diag << FixItHint::CreateInsertion(Initializer->getRParenLoc(), ")")
        << FixItHint::CreateInsertion(
               Initializer->getLParenLoc().getLocWithOffset(1), "std::move(")
-       << Inserter->CreateIncludeInsertion(
+       << Inserter.createIncludeInsertion(
               Result.SourceManager->getFileID(Initializer->getSourceLocation()),
               "utility",
               /*IsAngled=*/true);
 }
 
 } // namespace modernize
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.h

public:
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  std::unique_ptr<utils::IncludeInserter> Inserter;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  utils::IncludeInserter Inserter;
 };
 
 } // namespace modernize
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_REPLACE_AUTO_PTR_H

clang-tools-extra/clang-tidy/modernize/ReplaceAutoPtrCheck.cpp

AST_MATCHER(Decl, isFromStdNamespace) {
   return (Info && Info->isStr("std"));
 }
 
 } // namespace
 
 ReplaceAutoPtrCheck::ReplaceAutoPtrCheck(StringRef Name,
                                          ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            utils::IncludeSorter::IS_LLVM)) {}
+      Inserter(Options.getLocalOrGlobal("IncludeStyle",
 
 void ReplaceAutoPtrCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
 }
 
 void ReplaceAutoPtrCheck::registerMatchers(MatchFinder *Finder) {
   auto AutoPtrDecl = recordDecl(hasName("auto_ptr"), isFromStdNamespace());
   auto AutoPtrType = qualType(hasDeclaration(AutoPtrDecl));
 
   //   std::auto_ptr<int> a;
   //        ^~~~~~~~~~~~~
Finder->addMatcher(
                cxxConstructExpr(hasType(AutoPtrType), argumentCountIs(1),
                                 hasArgument(0, MovableArgumentMatcher))),
       this);
 }
 
 void ReplaceAutoPtrCheck::registerPPCallbacks(const SourceManager &SM,
                                               Preprocessor *PP,
                                               Preprocessor *ModuleExpanderPP) {
-  Inserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
-                                                       IncludeStyle);
-  PP->addPPCallbacks(Inserter->CreatePPCallbacks());
+  Inserter.registerPreprocessor(PP);
 }
 
 void ReplaceAutoPtrCheck::check(const MatchFinder::MatchResult &Result) {
   SourceManager &SM = *Result.SourceManager;
   if (const auto *E =
           Result.Nodes.getNodeAs<Expr>(AutoPtrOwnershipTransferId)) {
     CharSourceRange Range = Lexer::makeFileCharRange(
         CharSourceRange::getTokenRange(E->getSourceRange()), SM, LangOptions());
 
     if (Range.isInvalid())
       return;
 
-    auto Diag =
-        diag(Range.getBegin(), "use std::move to transfer ownership")
+    auto Diag = diag(Range.getBegin(), "use std::move to transfer ownership")
                 << FixItHint::CreateInsertion(Range.getBegin(), "std::move(")
                 << FixItHint::CreateInsertion(Range.getEnd(), ")")
-        << Inserter->CreateIncludeInsertion(SM.getMainFileID(), "utility",
+                << Inserter.createMainFileIncludeInsertion("utility",
                                                            /*IsAngled=*/true);
 
     return;
   }
 
   SourceLocation AutoPtrLoc;
   if (const auto *TL = Result.Nodes.getNodeAs<TypeLoc>(AutoPtrTokenId)) {
     //   std::auto_ptr<int> i;
     //        ^

clang-tools-extra/clang-tidy/modernize/ReplaceRandomShuffleCheck.h

public:
   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override {
     return LangOpts.CPlusPlus11;
   }
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  std::unique_ptr<utils::IncludeInserter> IncludeInserter;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  utils::IncludeInserter IncludeInserter;
 };
 
 } // namespace modernize
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_MODERNIZE_REPLACE_RANDOM_SHUFFLE_H

clang-tools-extra/clang-tidy/modernize/ReplaceRandomShuffleCheck.cpp

 
 namespace clang {
 namespace tidy {
 namespace modernize {
 
 ReplaceRandomShuffleCheck::ReplaceRandomShuffleCheck(StringRef Name,
                                                      ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            utils::IncludeSorter::IS_LLVM)) {}
+      IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
+                                               utils::IncludeSorter::IS_LLVM)) {
+}
 
 void ReplaceRandomShuffleCheck::registerMatchers(MatchFinder *Finder) {
   const auto Begin = hasArgument(0, expr());
   const auto End = hasArgument(1, expr());
   const auto RandomFunc = hasArgument(2, expr().bind("randomFunc"));
   Finder->addMatcher(
       traverse(
           ast_type_traits::TK_AsIs,
           callExpr(
               anyOf(allOf(Begin, End, argumentCountIs(2)),
                     allOf(Begin, End, RandomFunc, argumentCountIs(3))),
               hasDeclaration(functionDecl(hasName("::std::random_shuffle"))),
               has(implicitCastExpr(has(declRefExpr().bind("name")))))
               .bind("match")),
       this);
 }
 
 void ReplaceRandomShuffleCheck::registerPPCallbacks(
     const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
-  IncludeInserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
-                                                              IncludeStyle);
-  PP->addPPCallbacks(IncludeInserter->CreatePPCallbacks());
+  IncludeInserter.registerPreprocessor(PP);
 }
 
 void ReplaceRandomShuffleCheck::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
 }
 
 void ReplaceRandomShuffleCheck::check(const MatchFinder::MatchResult &Result) {
   const auto *MatchedDecl = Result.Nodes.getNodeAs<DeclRefExpr>("name");
   const auto *MatchedArgumentThree = Result.Nodes.getNodeAs<Expr>("randomFunc");
   const auto *MatchedCallExpr = Result.Nodes.getNodeAs<CallExpr>("match");
 
   if (MatchedCallExpr->getBeginLoc().isMacroID())
void ReplaceRandomShuffleCheck::check(const MatchFinder::MatchResult &Result) {
   StringRef ContainerText = Lexer::getSourceText(
       CharSourceRange::getTokenRange(MatchedDecl->getSourceRange()),
       *Result.SourceManager, getLangOpts());
   if (ContainerText.startswith("std::"))
     NewName = "std::" + NewName;
 
   Diag << FixItHint::CreateRemoval(MatchedDecl->getSourceRange());
   Diag << FixItHint::CreateInsertion(MatchedDecl->getBeginLoc(), NewName);
-  Diag << IncludeInserter->CreateIncludeInsertion(
+  Diag << IncludeInserter.createIncludeInsertion(
       Result.Context->getSourceManager().getFileID(
           MatchedCallExpr->getBeginLoc()),
       "random", /*IsAngled=*/true);
 }
 
 } // namespace modernize
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clang-tidy/performance/MoveConstructorInitCheck.h

public:
   }
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override;
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
 
 private:
-  std::unique_ptr<utils::IncludeInserter> Inserter;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  utils::IncludeInserter Inserter;
 };
 
 } // namespace performance
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_PERFORMANCE_MOVECONSTRUCTORINITCHECK_H

clang-tools-extra/clang-tidy/performance/MoveConstructorInitCheck.cpp

 
 namespace clang {
 namespace tidy {
 namespace performance {
 
 MoveConstructorInitCheck::MoveConstructorInitCheck(StringRef Name,
                                                    ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            utils::IncludeSorter::IS_LLVM)) {}
+      Inserter(Options.getLocalOrGlobal("IncludeStyle",
 
 void MoveConstructorInitCheck::registerMatchers(MatchFinder *Finder) {
   Finder->addMatcher(
       traverse(ast_type_traits::TK_AsIs,
                cxxConstructorDecl(
                    unless(isImplicit()), isMoveConstructor(),
                    hasAnyConstructorInitializer(
                        cxxCtorInitializer(
diag(CopyCtor->getLocation(), "copy constructor being called",
          DiagnosticIDs::Note);
     diag(Candidate->getLocation(), "candidate move constructor here",
          DiagnosticIDs::Note);
   }
 }
 
 void MoveConstructorInitCheck::registerPPCallbacks(
     const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
-  Inserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
-                                                       IncludeStyle);
-  PP->addPPCallbacks(Inserter->CreatePPCallbacks());
+  Inserter.registerPreprocessor(PP);
 }
 
 void MoveConstructorInitCheck::storeOptions(ClangTidyOptions::OptionMap &Opts) {
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
 }
 
 } // namespace performance
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clang-tidy/performance/TypePromotionInMathFnCheck.h

public:
 
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override;
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
 
 private:
-  std::unique_ptr<utils::IncludeInserter> IncludeInserter;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  utils::IncludeInserter IncludeInserter;
 };
 
 } // namespace performance
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_PERFORMANCE_TYPE_PROMOTION_IN_MATH_FN_H

clang-tools-extra/clang-tidy/performance/TypePromotionInMathFnCheck.cpp

AST_MATCHER_P(Type, isBuiltinType, BuiltinType::Kind, Kind) {
   }
   return false;
 }
 } // anonymous namespace
 
 TypePromotionInMathFnCheck::TypePromotionInMathFnCheck(
     StringRef Name, ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            utils::IncludeSorter::IS_LLVM)) {}
+      IncludeInserter(Options.getLocalOrGlobal("IncludeStyle",
+                                               utils::IncludeSorter::IS_LLVM)) {
+}
 
 void TypePromotionInMathFnCheck::registerPPCallbacks(
     const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
-  IncludeInserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
-                                                              IncludeStyle);
-  PP->addPPCallbacks(IncludeInserter->CreatePPCallbacks());
+  IncludeInserter.registerPreprocessor(PP);
 }
 
 void TypePromotionInMathFnCheck::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", IncludeInserter.getStyle());
 }
 
 void TypePromotionInMathFnCheck::registerMatchers(MatchFinder *Finder) {
   constexpr BuiltinType::Kind IntTy = BuiltinType::Int;
   constexpr BuiltinType::Kind LongTy = BuiltinType::Long;
   constexpr BuiltinType::Kind FloatTy = BuiltinType::Float;
   constexpr BuiltinType::Kind DoubleTy = BuiltinType::Double;
   constexpr BuiltinType::Kind LongDoubleTy = BuiltinType::LongDouble;
auto Diag = diag(Call->getExprLoc(), "call to '%0' promotes float to double")
               << FixItHint::CreateReplacement(
                      Call->getCallee()->getSourceRange(), NewFnName);
 
   // Suggest including <cmath> if the function we're suggesting is declared in
   // <cmath> and it's not already included.  We never have to suggest including
   // <math.h>, because the functions we're suggesting moving away from are all
   // declared in <math.h>.
   if (FnInCmath)
-    Diag << IncludeInserter->CreateIncludeInsertion(
+    Diag << IncludeInserter.createIncludeInsertion(
         Result.Context->getSourceManager().getFileID(Call->getBeginLoc()),
         "cmath", /*IsAngled=*/true);
 }
 
 } // namespace performance
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.h

public:
   void onEndOfTranslationUnit() override;
 
 private:
   void handleMoveFix(const ParmVarDecl &Var, const DeclRefExpr &CopyArgument,
                      const ASTContext &Context);
 
   llvm::DenseMap<const FunctionDecl *, FunctionParmMutationAnalyzer>
       MutationAnalyzers;
-  std::unique_ptr<utils::IncludeInserter> Inserter;
-  const utils::IncludeSorter::IncludeStyle IncludeStyle;
+  utils::IncludeInserter Inserter;
   const std::vector<std::string> AllowedTypes;
 };
 
 } // namespace performance
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_PERFORMANCE_UNNECESSARY_VALUE_PARAM_H

clang-tools-extra/clang-tidy/performance/UnnecessaryValueParamCheck.cpp

bool isExplicitTemplateSpecialization(const FunctionDecl &Function) {
   return false;
 }
 
 } // namespace
 
 UnnecessaryValueParamCheck::UnnecessaryValueParamCheck(
     StringRef Name, ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            utils::IncludeSorter::IS_LLVM)),
+      Inserter(Options.getLocalOrGlobal("IncludeStyle",
       AllowedTypes(
           utils::options::parseStringList(Options.get("AllowedTypes", ""))) {}
 
 void UnnecessaryValueParamCheck::registerMatchers(MatchFinder *Finder) {
   const auto ExpensiveValueParamDecl = parmVarDecl(
       hasType(qualType(
           hasCanonicalType(matchers::isExpensiveToCopy()),
           unless(anyOf(hasCanonicalType(referenceType()),
if (!CurrentParam.getType().getCanonicalType().isConstQualified()) {
               CurrentParam, *Result.Context, DeclSpec::TQ::TQ_const))
         Diag << *Fix;
     }
   }
 }
 
 void UnnecessaryValueParamCheck::registerPPCallbacks(
     const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
-  Inserter = std::make_unique<utils::IncludeInserter>(SM, getLangOpts(),
-                                                      IncludeStyle);
-  PP->addPPCallbacks(Inserter->CreatePPCallbacks());
+  Inserter.registerPreprocessor(PP);
 }
 
 void UnnecessaryValueParamCheck::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
   Options.store(Opts, "AllowedTypes",
                 utils::options::serializeStringList(AllowedTypes));
 }
 
 void UnnecessaryValueParamCheck::onEndOfTranslationUnit() {
   MutationAnalyzers.clear();
 }
 
 void UnnecessaryValueParamCheck::handleMoveFix(const ParmVarDecl &Var,
                                                const DeclRefExpr &CopyArgument,
                                                const ASTContext &Context) {
   auto Diag = diag(CopyArgument.getBeginLoc(),
                    "parameter %0 is passed by value and only copied once; "
                    "consider moving it to avoid unnecessary copies")
               << &Var;
   // Do not propose fixes in macros since we cannot place them correctly.
   if (CopyArgument.getBeginLoc().isMacroID())
     return;
   const auto &SM = Context.getSourceManager();
   auto EndLoc = Lexer::getLocForEndOfToken(CopyArgument.getLocation(), 0, SM,
                                            Context.getLangOpts());
   Diag << FixItHint::CreateInsertion(CopyArgument.getBeginLoc(), "std::move(")
        << FixItHint::CreateInsertion(EndLoc, ")")
-       << Inserter->CreateIncludeInsertion(
+       << Inserter.createIncludeInsertion(
               SM.getFileID(CopyArgument.getBeginLoc()), "utility",
               /*IsAngled=*/true);
 }
 
 } // namespace performance
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clang-tidy/utils/IncludeInserter.h

 //===---------- IncludeInserter.h - clang-tidy ----------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_INCLUDEINSERTER_H
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_INCLUDEINSERTER_H
 
 #include "IncludeSorter.h"
 #include "clang/Basic/Diagnostic.h"
-#include "clang/Basic/LangOptions.h"
-#include "clang/Basic/SourceManager.h"
-#include "clang/Lex/PPCallbacks.h"
+#include "llvm/ADT/StringSet.h"
 #include <memory>
-#include <string>
 
 namespace clang {
+class Preprocessor;
 namespace tidy {
 namespace utils {
 
 /// Produces fixes to insert specified includes to source files, if not
 /// yet present.
 ///
 /// ``IncludeInserter`` can be used in clang-tidy checks in the following way:
 /// \code
+/// #include "../ClangTidyCheck.h"
 /// #include "../utils/IncludeInserter.h"
-/// #include "clang/Frontend/CompilerInstance.h"
+///
+/// namespace clang {
+/// namespace tidy {
 ///
 /// class MyCheck : public ClangTidyCheck {
 ///  public:
 ///   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
 ///                            Preprocessor *ModuleExpanderPP) override {
-///     Inserter = std::make_unique<IncludeInserter>(
-///         SM, getLangOpts(), utils::IncludeSorter::IS_Google);
-///     PP->addPPCallbacks(Inserter->CreatePPCallbacks());
+///     Inserter.registerPreprocessor();
 ///   }
 ///
 ///   void registerMatchers(ast_matchers::MatchFinder* Finder) override { ... }
 ///
 ///   void check(
 ///       const ast_matchers::MatchFinder::MatchResult& Result) override {
 ///     ...
-///     Inserter->CreateIncludeInsertion(
-///         Result.SourceManager->getMainFileID(), "path/to/Header.h",
-///         /*IsAngled=*/false);
+///     Inserter.createMainFileIncludeInsertion("path/to/Header.h",
+///                                             /*IsAngled=*/false);
 ///     ...
 ///   }
 ///
 ///  private:
-///   std::unique_ptr<clang::tidy::utils::IncludeInserter> Inserter;
+///   utils::IncludeInserter Inserter{utils::IncludeSorter::IS_Google};
 /// };
+/// } // namespace tidy
+/// } // namespace clang
 /// \endcode
 class IncludeInserter {
 public:
-  IncludeInserter(const SourceManager &SourceMgr, const LangOptions &LangOpts,
-                  IncludeSorter::IncludeStyle Style);
-  ~IncludeInserter();
+  /// Initializes the IncludeInserter using the IncludeStyle \p Style.
+  /// In most cases the \p Style will be retrieved from the ClangTidyOptions
+  /// using \code
+  ///   Options.getLocalOrGlobal("IncludeStyle", <DefaultStyle>)
+  /// \endcode
+  explicit IncludeInserter(IncludeSorter::IncludeStyle Style);
 
-  /// Create ``PPCallbacks`` for registration with the compiler's preprocessor.
-  std::unique_ptr<PPCallbacks> CreatePPCallbacks();
+  /// Registers this with the Preprocessor \p PP, must be called before this
+  /// class is used.
+  void registerPreprocessor(Preprocessor *PP);
+
+  /// Creates a \p Header inclusion directive fixit in the File \p FileID.
+  /// Returns ``llvm::None`` on error or if the inclusion directive already
+  /// exists.
+  llvm::Optional<FixItHint>
+  createIncludeInsertion(FileID FileID, llvm::StringRef Header, bool IsAngled);
 
-  /// Creates a \p Header inclusion directive fixit. Returns ``llvm::None`` on
-  /// error or if inclusion directive already exists.
+  /// Creates a \p Header inclusion directive fixit in the main file.
+  /// Returns``llvm::None`` on error or if the inclusion directive already
+  /// exists.
   llvm::Optional<FixItHint>
-  CreateIncludeInsertion(FileID FileID, llvm::StringRef Header, bool IsAngled);
+  createMainFileIncludeInsertion(llvm::StringRef Header, bool IsAngled);
+
+  IncludeSorter::IncludeStyle getStyle() const { return Style; }
 
 private:
-  void AddInclude(StringRef FileName, bool IsAngled,
+  void addInclude(StringRef FileName, bool IsAngled,
                   SourceLocation HashLocation, SourceLocation EndLocation);
 
   IncludeSorter &getOrCreate(FileID FileID);
 
   llvm::DenseMap<FileID, std::unique_ptr<IncludeSorter>> IncludeSorterByFile;
-  llvm::DenseMap<FileID, std::set<std::string>> InsertedHeaders;
-  const SourceManager &SourceMgr;
+  llvm::DenseMap<FileID, llvm::StringSet<>> InsertedHeaders;
+  const SourceManager *SourceMgr{nullptr};
   const IncludeSorter::IncludeStyle Style;
   friend class IncludeInserterCallback;
 };
 
 } // namespace utils
 } // namespace tidy
 } // namespace clang
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_INCLUDEINSERTER_H

clang-tools-extra/clang-tidy/utils/IncludeInserter.cpp

 //===-------- IncludeInserter.cpp - clang-tidy ----------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "IncludeInserter.h"
+#include "clang/Lex/PPCallbacks.h"
+#include "clang/Lex/Preprocessor.h"
 #include "clang/Lex/Token.h"
 
 namespace clang {
 namespace tidy {
 namespace utils {
 
 class IncludeInserterCallback : public PPCallbacks {
 public:
   explicit IncludeInserterCallback(IncludeInserter *Inserter)
       : Inserter(Inserter) {}
   // Implements PPCallbacks::InclusionDerective(). Records the names and source
   // locations of the inclusions in the main source file being processed.
   void InclusionDirective(SourceLocation HashLocation,
                           const Token &IncludeToken, StringRef FileNameRef,
                           bool IsAngled, CharSourceRange FileNameRange,
                           const FileEntry * /*IncludedFile*/,
                           StringRef /*SearchPath*/, StringRef /*RelativePath*/,
                           const Module * /*ImportedModule*/,
                           SrcMgr::CharacteristicKind /*FileType*/) override {
-    Inserter->AddInclude(FileNameRef, IsAngled, HashLocation,
+    Inserter->addInclude(FileNameRef, IsAngled, HashLocation,
                          IncludeToken.getEndLoc());
   }
 
 private:
   IncludeInserter *Inserter;
 };
 
-IncludeInserter::IncludeInserter(const SourceManager &SourceMgr,
-                                 const LangOptions &LangOpts,
-                                 IncludeSorter::IncludeStyle Style)
-    : SourceMgr(SourceMgr), Style(Style) {}
+IncludeInserter::IncludeInserter(IncludeSorter::IncludeStyle Style)
+    : Style(Style) {}
 
-IncludeInserter::~IncludeInserter() {}
-
-std::unique_ptr<PPCallbacks> IncludeInserter::CreatePPCallbacks() {
-  return std::make_unique<IncludeInserterCallback>(this);
+void IncludeInserter::registerPreprocessor(Preprocessor *PP) {
+  assert(PP && "PP shouldn't be null");
+  SourceMgr = &PP->getSourceManager();
+
+  // If this gets registered multiple times, clear the maps
+  if (!IncludeSorterByFile.empty())
+    IncludeSorterByFile.clear();
+  if (!InsertedHeaders.empty())
+    InsertedHeaders.clear();
+  PP->addPPCallbacks(std::make_unique<IncludeInserterCallback>(this));
 }
 
 IncludeSorter &IncludeInserter::getOrCreate(FileID FileID) {
+  assert(SourceMgr && "SourceMgr shouldn't be null; did you remember to call "
+                      "registerPreprocessor()?");
   // std::unique_ptr is cheap to construct, so force a construction now to save
   // the lookup needed if we were to insert into the map.
   std::unique_ptr<IncludeSorter> &Entry = IncludeSorterByFile[FileID];
   if (!Entry) {
     // If it wasn't found, Entry will be default constructed to nullptr.
     Entry = std::make_unique<IncludeSorter>(
-        &SourceMgr, FileID,
-        SourceMgr.getFilename(SourceMgr.getLocForStartOfFile(FileID)), Style);
+        SourceMgr, FileID,
+        SourceMgr->getFilename(SourceMgr->getLocForStartOfFile(FileID)), Style);
   }
   return *Entry;
 }
 
 llvm::Optional<FixItHint>
-IncludeInserter::CreateIncludeInsertion(FileID FileID, StringRef Header,
+IncludeInserter::createIncludeInsertion(FileID FileID, StringRef Header,
                                         bool IsAngled) {
   // We assume the same Header will never be included both angled and not
   // angled.
-  if (!InsertedHeaders[FileID].insert(std::string(Header)).second)
+  if (!InsertedHeaders[FileID].insert(Header).second)
     return llvm::None;
 
   return getOrCreate(FileID).CreateIncludeInsertion(Header, IsAngled);
 }
 
-void IncludeInserter::AddInclude(StringRef FileName, bool IsAngled,
+llvm::Optional<FixItHint>
+IncludeInserter::createMainFileIncludeInsertion(StringRef Header,
+                                                bool IsAngled) {
+  assert(SourceMgr && "SourceMgr shouldn't be null; did you remember to call "
+                      "registerPreprocessor()?");
+  return createIncludeInsertion(SourceMgr->getMainFileID(), Header, IsAngled);
+}
+
+void IncludeInserter::addInclude(StringRef FileName, bool IsAngled,
                                  SourceLocation HashLocation,
                                  SourceLocation EndLocation) {
-  FileID FileID = SourceMgr.getFileID(HashLocation);
+  assert(SourceMgr && "SourceMgr shouldn't be null; did you remember to call "
+                      "registerPreprocessor()?");
+  FileID FileID = SourceMgr->getFileID(HashLocation);
   getOrCreate(FileID).AddInclude(FileName, IsAngled, HashLocation, EndLocation);
 }
 
 } // namespace utils
 } // namespace tidy
 } // namespace clang

clang-tools-extra/clang-tidy/utils/TransformerClangTidyCheck.h

public:
   void check(const ast_matchers::MatchFinder::MatchResult &Result) final;
 
   /// Derived classes that override this function should call this method from
   /// the overridden method.
   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
 
 private:
   Optional<transformer::RewriteRule> Rule;
-  const IncludeSorter::IncludeStyle IncludeStyle;
-  std::unique_ptr<IncludeInserter> Inserter;
+  IncludeInserter Inserter;
 };
 
 } // namespace utils
 } // namespace tidy
 } // namespace clang
 
 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_TRANSFORMER_CLANG_TIDY_CHECK_H

clang-tools-extra/clang-tidy/utils/TransformerClangTidyCheck.cpp

 // we would be accessing `getLangOpts` and `Options` before the underlying
 // `ClangTidyCheck` instance was properly initialized.
 TransformerClangTidyCheck::TransformerClangTidyCheck(
     std::function<Optional<RewriteRule>(const LangOptions &,
                                         const OptionsView &)>
         MakeRule,
     StringRef Name, ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context), Rule(MakeRule(getLangOpts(), Options)),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            IncludeSorter::IS_LLVM)) {
+      Inserter(
+          Options.getLocalOrGlobal("IncludeStyle", IncludeSorter::IS_LLVM)) {
   if (Rule)
     assert(llvm::all_of(Rule->Cases, hasExplanation) &&
            "clang-tidy checks must have an explanation by default;"
            " explicitly provide an empty explanation if none is desired");
 }
 
 TransformerClangTidyCheck::TransformerClangTidyCheck(RewriteRule R,
                                                      StringRef Name,
                                                      ClangTidyContext *Context)
     : ClangTidyCheck(Name, Context), Rule(std::move(R)),
-      IncludeStyle(Options.getLocalOrGlobal("IncludeStyle",
-                                            IncludeSorter::IS_LLVM)) {
+      Inserter(
+          Options.getLocalOrGlobal("IncludeStyle", IncludeSorter::IS_LLVM)) {
   assert(llvm::all_of(Rule->Cases, hasExplanation) &&
          "clang-tidy checks must have an explanation by default;"
          " explicitly provide an empty explanation if none is desired");
 }
 
 void TransformerClangTidyCheck::registerPPCallbacks(
     const SourceManager &SM, Preprocessor *PP, Preprocessor *ModuleExpanderPP) {
-  // Only allocate and register the IncludeInsert when some `Case` will add
+  // Only register the IncludeInsert when some `Case` will add
   // includes.
   if (Rule && llvm::any_of(Rule->Cases, [](const RewriteRule::Case &C) {
         return !C.AddedIncludes.empty();
-      })) {
-    Inserter =
-        std::make_unique<IncludeInserter>(SM, getLangOpts(), IncludeStyle);
-    PP->addPPCallbacks(Inserter->CreatePPCallbacks());
-  }
+      }))
+    Inserter.registerPreprocessor(PP);
 }
 
 void TransformerClangTidyCheck::registerMatchers(
     ast_matchers::MatchFinder *Finder) {
   if (Rule)
     for (auto &Matcher : transformer::detail::buildMatchers(*Rule))
       Finder->addDynamicMatcher(Matcher, this);
 }
void TransformerClangTidyCheck::check(
   }
 
   // Associate the diagnostic with the location of the first change.
   DiagnosticBuilder Diag = diag((*Edits)[0].Range.getBegin(), *Explanation);
   for (const auto &T : *Edits)
     Diag << FixItHint::CreateReplacement(T.Range, T.Replacement);
 
   for (const auto &I : Case.AddedIncludes) {
-    Diag << Inserter->CreateIncludeInsertion(
-        Result.SourceManager->getMainFileID(), I.first,
+    Diag << Inserter.createMainFileIncludeInsertion(
+        I.first,
         /*IsAngled=*/I.second == transformer::IncludeFormat::Angled);
   }
 }
 
 void TransformerClangTidyCheck::storeOptions(
     ClangTidyOptions::OptionMap &Opts) {
-  Options.store(Opts, "IncludeStyle", IncludeStyle);
+  Options.store(Opts, "IncludeStyle", Inserter.getStyle());
 }
 
 } // namespace utils
 } // namespace tidy
 } // namespace clang

clang-tools-extra/unittests/clang-tidy/IncludeInserterTest.cpp

 
 class IncludeInserterCheckBase : public ClangTidyCheck {
 public:
   IncludeInserterCheckBase(StringRef CheckName, ClangTidyContext *Context)
       : ClangTidyCheck(CheckName, Context) {}
 
   void registerPPCallbacks(const SourceManager &SM, Preprocessor *PP,
                            Preprocessor *ModuleExpanderPP) override {
-    Inserter = std::make_unique<utils::IncludeInserter>(
-        SM, getLangOpts(), utils::IncludeSorter::IS_Google);
-    PP->addPPCallbacks(Inserter->CreatePPCallbacks());
+    Inserter.registerPreprocessor(PP);
   }
 
   void registerMatchers(ast_matchers::MatchFinder *Finder) override {
     Finder->addMatcher(ast_matchers::declStmt().bind("stmt"), this);
   }
 
   void check(const ast_matchers::MatchFinder::MatchResult &Result) override {
     auto Diag = diag(Result.Nodes.getNodeAs<DeclStmt>("stmt")->getBeginLoc(),
                      "foo, bar");
     for (StringRef Header : HeadersToInclude()) {
-      Diag << Inserter->CreateIncludeInsertion(
-          Result.SourceManager->getMainFileID(), Header, IsAngledInclude());
+      Diag << Inserter.createMainFileIncludeInsertion(Header,
+                                                      IsAngledInclude());
     }
   }
 
   virtual std::vector<StringRef> HeadersToInclude() const = 0;
   virtual bool IsAngledInclude() const = 0;
 
-  std::unique_ptr<utils::IncludeInserter> Inserter;
+  utils::IncludeInserter Inserter{utils::IncludeSorter::IS_Google};
 };
 
 class NonSystemHeaderInserterCheck : public IncludeInserterCheckBase {
 public:
   NonSystemHeaderInserterCheck(StringRef CheckName, ClangTidyContext *Context)
       : IncludeInserterCheckBase(CheckName, Context) {}
 
   std::vector<StringRef> HeadersToInclude() const override {