An IRBuilder for s-expressions?

I’ve found myself building a lightweight wrapper on top of IRBuilder for generating IR from typeless s-expressions. It consists of two parts:

  1. An s-expression parser and AST.
  2. A plugin system for translating the AST into IRBuilder calls.

Does any of this functionality already exist, perhaps in Clang? If not, is there any interest in seeing it upstream? I would be happy to put together a patch and maintain it.