[clang][dataflow] Add reachedLimit() to the Solver interface. (llvm#91320)

We may want code to call this that doesn't know which specific solver
implementation it is dealing with.

Author: martinboehme

clang/include/clang/Analysis/FlowSensitive/Solver.h

@@ -87,6 +87,9 @@ class Solver {
   ///
   ///  All elements in `Vals` must not be null.
   virtual Result solve(llvm::ArrayRef<const Formula *> Vals) = 0;
+
+  // Did the solver reach its resource limit?
+  virtual bool reachedLimit() const = 0;
 };
 
 llvm::raw_ostream &operator<<(llvm::raw_ostream &, const Solver::Result &);

clang/include/clang/Analysis/FlowSensitive/WatchedLiteralsSolver.h

@@ -48,8 +48,7 @@ class WatchedLiteralsSolver : public Solver {
 
   Result solve(llvm::ArrayRef<const Formula *> Vals) override;
 
-  // The solver reached its maximum number of iterations.
-  bool reachedLimit() const { return MaxIterations == 0; }
+  bool reachedLimit() const override { return MaxIterations == 0; }
 };
 
 } // namespace dataflow