[clang] [analyzer][NFC] Introduce framework for checker families (PR #139256)

[Donát Nagy via cfe-commits]

================
@@ -25,25 +25,23 @@ using namespace ento;
 using namespace taint;
 
 namespace {
-class DivZeroChecker : public Checker<check::PreStmt<BinaryOperator>> {
+class DivZeroChecker : public CheckerFamily<check::PreStmt<BinaryOperator>> {
   void reportBug(StringRef Msg, ProgramStateRef StateZero,
                  CheckerContext &C) const;
   void reportTaintBug(StringRef Msg, ProgramStateRef StateZero,
                       CheckerContext &C,
                       llvm::ArrayRef<SymbolRef> TaintedSyms) const;
 
 public:
-  /// This checker class implements several user facing checkers
-  enum : CheckerPartIdx {
-    DivideZeroChecker,
-    TaintedDivChecker,
-    NumCheckerParts
-  };
-  BugType BugTypes[NumCheckerParts] = {
-      {this, DivideZeroChecker, "Division by zero"},
-      {this, TaintedDivChecker, "Division by zero", categories::TaintedData}};
+  /// This checker family implements two user-facing checker parts.
+  CheckerFrontendWithBugType DivideZeroChecker{"Division by zero"},
+      TaintedDivChecker{"Division by zero", categories::TaintedData};
 
   void checkPreStmt(const BinaryOperator *B, CheckerContext &C) const;
+
+  /// Identifies this checker family for debugging purposes. For backwards
+  /// compatibility, this is the name of the older sub-checker.
+  StringRef getTagDescription() const override { return "core.DivideZero"; }
----------------
NagyDonat wrote:

When I wrote this commit I preserved the tag description `"core.DivideZero"` because it was tested by `ftime-trace.cpp`. However, now I'm convinced that the old behavior where the tag description was the name of one sub-checker in the family (the first one) is inelegant, because the tag description should clearly identify the whole family.

To ensure this, I created commit https://github.com/llvm/llvm-project/pull/139256/commits/8459b2f19139a6444d7a219c611bc085bced8e18 which changes the tag description to `DivZeroChecker` (the class name), which seems to be a natural choice. (Note that in `VirtualCallChecker` I already used the class name as a tag description when I first uploaded this PR.)

https://github.com/llvm/llvm-project/pull/139256