We'll need to add support for exception handling in Wasmer (runtime/VM level):

https://github.com/WebAssembly/exception-handling

Basically, Wasmer needs add the exception-handling WAST tests to our repo, and also pass them.
https://github.com/WebAssembly/exception-handling/tree/main/test/core

Note: we can start with singlepass, then LLVM and Cranelift last (it might be a bit harder in cranelift or require a fork, so we'll leave it to be the last one)