[analyzer] Pass through all arguments from the registerChecker() to the checker constructor

[george.karpenkov]

Summary

A lot of checkers could be cleaned up in a similar way

[NoQ]

Looks pretty great!

include/clang/StaticAnalyzer/Core/CheckerManager.h

public:
   using CheckerTag = const void *;
   using CheckerDtor = CheckerFn<void ()>;
 
 //===----------------------------------------------------------------------===//
 // registerChecker
 //===----------------------------------------------------------------------===//
 
   /// Used to register checkers.
+  /// All arguments are automatically passed through to the checker
+  /// constructor.
   ///
   /// \returns a pointer to the checker object.
-  template <typename CHECKER>
-  CHECKER *registerChecker() {
-    CheckerTag tag = getTag<CHECKER>();
-    CheckerRef &ref = CheckerTags[tag];
-    if (ref)
-      return static_cast<CHECKER *>(ref); // already registered.
-
-    CHECKER *checker = new CHECKER();
-    checker->Name = CurrentCheckName;
-    CheckerDtors.push_back(CheckerDtor(checker, destruct<CHECKER>));
-    CHECKER::_register(checker, *this);
-    ref = checker;
-    return checker;
-  }
-
-  template <typename CHECKER>
-  CHECKER *registerChecker(AnalyzerOptions &AOpts) {
+  template <typename CHECKER, typename... AT>
+  CHECKER *registerChecker(AT... Args) {
     CheckerTag tag = getTag<CHECKER>();
     CheckerRef &ref = CheckerTags[tag];
     if (ref)
       return static_cast<CHECKER *>(ref); // already registered.
 
-    CHECKER *checker = new CHECKER(AOpts);
+    CHECKER *checker = new CHECKER(Args...);
     checker->Name = CurrentCheckName;
     CheckerDtors.push_back(CheckerDtor(checker, destruct<CHECKER>));
     CHECKER::_register(checker, *this);
     ref = checker;
     return checker;
   }
 
 //===----------------------------------------------------------------------===//

lib/StaticAnalyzer/Checkers/DynamicTypePropagation.cpp

 class DynamicTypePropagation:
     public Checker< check::PreCall,
                     check::PostCall,
                     check::DeadSymbols,
                     check::PostStmt<CastExpr>,
                     check::PostStmt<CXXNewExpr>,
                     check::PreObjCMessage,
                     check::PostObjCMessage > {
+private:
+  /// This value is set to true, when the Generics checker is turned on.
+  bool CheckGenerics;
+public:
+  DynamicTypePropagation(bool CheckGenerics)
+      : CheckGenerics(CheckGenerics) {}
   const ObjCObjectType *getObjectTypeForAllocAndNew(const ObjCMessageExpr *MsgE,
                                                     CheckerContext &C) const;
 
   /// Return a better dynamic type if one can be derived from the cast.
   const ObjCObjectPointerType *getBetterObjCType(const Expr *CastE,
                                                  CheckerContext &C) const;
 
   ExplodedNode *dynamicTypePropagationOnCasts(const CastExpr *CE,

 public:
   void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
   void checkPostCall(const CallEvent &Call, CheckerContext &C) const;
   void checkPostStmt(const CastExpr *CastE, CheckerContext &C) const;
   void checkPostStmt(const CXXNewExpr *NewE, CheckerContext &C) const;
   void checkDeadSymbols(SymbolReaper &SR, CheckerContext &C) const;
   void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const;
   void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const;
-
-  /// This value is set to true, when the Generics checker is turned on.
-  DefaultBool CheckGenerics;
 };
 } // end anonymous namespace
 
 void DynamicTypePropagation::checkDeadSymbols(SymbolReaper &SR,
                                               CheckerContext &C) const {
   ProgramStateRef State = C.getState();
   DynamicTypeMapImpl TypeMap = State->get<DynamicTypeMap>();
   for (DynamicTypeMapImpl::iterator I = TypeMap.begin(), E = TypeMap.end();
DynamicTypePropagation::GenericsBugVisitor::VisitNode(const ExplodedNode *N,
   PathDiagnosticLocation Pos(S, BRC.getSourceManager(),
                              N->getLocationContext());
   return std::make_shared<PathDiagnosticEventPiece>(Pos, OS.str(), true,
                                                     nullptr);
 }
 
 /// Register checkers.
 void ento::registerObjCGenericsChecker(CheckerManager &mgr) {
-  DynamicTypePropagation *checker =
-      mgr.registerChecker<DynamicTypePropagation>();
-  checker->CheckGenerics = true;
+  mgr.registerChecker<DynamicTypePropagation>(/*CheckGenerics=*/true);
 }
 
 void ento::registerDynamicTypePropagation(CheckerManager &mgr) {
-  mgr.registerChecker<DynamicTypePropagation>();
+  mgr.registerChecker<DynamicTypePropagation>(/*CheckGenerics=*/false);
 }