[clang] [llvm] [ARM] Emit an error when the hard-float ABI is enabled but can't be used. (PR #111334)

[David Green via cfe-commits]

davemgreen wrote:

I agree but was having trouble putting it into words. I don't have a reference I can put my hands on, but we have generally considered the llvm error messages to be a poor substitute to those produced by clang and have often gone the other way, converting llvm errors to clang errors.  I would think the best interface here is a error/warning that is downgradable to a warning/silent and that is difficult to do in llvm at the moment with the way the errors are setup. They are mostly reserved for things that have gone very wrong or cannot be supported.

It would be good to share this kind of logic where we can though. Either by building a proper way for the backends to report errors to the frontends, or for the logic to be shared in TargetParser.

https://github.com/llvm/llvm-project/pull/111334