[Analyzer] Mark constant member functions const in CheckerManager

Most of the getter functions (and a reporter function) in
`CheckerManager` are constant but not marked as `const`. This prevents
functions having only a constant reference to `CheckerManager` using
these member functions. This patch fixes this issue.

Differential Revision: https://reviews.llvm.org/D75839

clang/include/clang/StaticAnalyzer/Core/CheckerManager.h

@@ -140,14 +140,14 @@ class CheckerManager {
   void finishedCheckerRegistration();
 
   const LangOptions &getLangOpts() const { return LangOpts; }
-  AnalyzerOptions &getAnalyzerOptions() { return AOptions; }
-  ASTContext &getASTContext() { return Context; }
+  AnalyzerOptions &getAnalyzerOptions() const { return AOptions; }
+  ASTContext &getASTContext() const { return Context; }
 
   /// Emits an error through a DiagnosticsEngine about an invalid user supplied
   /// checker option value.
   void reportInvalidCheckerOptionValue(const CheckerBase *C,
                                        StringRef OptionName,
-                                       StringRef ExpectedValueDesc);
+                                       StringRef ExpectedValueDesc) const;
 
   using CheckerRef = CheckerBase *;
   using CheckerTag = const void *;
@@ -620,7 +620,7 @@ class CheckerManager {
   /// Returns the checkers that have registered for callbacks of the
   /// given \p Kind.
   const std::vector<CheckObjCMessageFunc> &
-  getObjCMessageCheckers(ObjCMessageVisitKind Kind);
+  getObjCMessageCheckers(ObjCMessageVisitKind Kind) const;
 
   std::vector<CheckObjCMessageFunc> PreObjCMessageCheckers;
   std::vector<CheckObjCMessageFunc> PostObjCMessageCheckers;

clang/lib/StaticAnalyzer/Core/CheckerManager.cpp

@@ -61,7 +61,8 @@ void CheckerManager::finishedCheckerRegistration() {
 }
 
 void CheckerManager::reportInvalidCheckerOptionValue(
-    const CheckerBase *C, StringRef OptionName, StringRef ExpectedValueDesc) {
+    const CheckerBase *C, StringRef OptionName,
+    StringRef ExpectedValueDesc) const {
 
   Context.getDiagnostics()
       .Report(diag::err_analyzer_checker_option_invalid_input)
@@ -249,7 +250,7 @@ void CheckerManager::runCheckersForObjCMessage(ObjCMessageVisitKind visitKind,
 }
 
 const std::vector<CheckerManager::CheckObjCMessageFunc> &
-CheckerManager::getObjCMessageCheckers(ObjCMessageVisitKind Kind) {
+CheckerManager::getObjCMessageCheckers(ObjCMessageVisitKind Kind) const {
   switch (Kind) {
   case ObjCMessageVisitKind::Pre:
     return PreObjCMessageCheckers;