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

[Donát Nagy via cfe-commits]

NagyDonat wrote:

> I think the order is deterministic, and due to how checker dependencies are resolved, the backend checker would be always the one that is registered first. I have not checked this.

You're correct wrt the current state of the code but I'm planning to get rid of many "backend/modeling" checkers that have no real purpose :sweat_smile:  -- in my opinion having a superfluous checker definition in `Checkers.td` is even worse than having a boilerplate `getDebugName` override.

There are a few modeling checkers that fulfill a valid role because they act as dependencies of checkers defined in other files/classes, but I want to eliminate the pattern where a checker class defines a modeling checker which is the dependency of the other "real" checkers from the class (to be registered first) and does nothing useful.

> I opted for this solution given my very limited time frame and that I shouldn't block the progress of this PR.

Sorry for adding time pressure... 

> I firmly believe that as this is a debugging feature, the best name to print is the class that gets registered.

I agree, but unfortunately there is no way to get the class name automatically in a platform-independent way without a third-party dependency like [the type_name boost library](https://www.boost.org/doc/libs/master/libs/core/doc/html/core/type_name.html). (Do I understand it correctly that we cannot just drop in an external dependency like this?)

Using the name of one subchecker is probably the least bad available approach and your code is an elegant implementation for it, so I'll probably apply it to get this PR merged. If you're not opposed, I would like to add a `family-of-` prefix to the debug names, which is a bit awkward but eliminates the ambiguity and the potential for confusion (somebody who briefly looks at some debug output will immediately see that the name identifies the _family_).



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