[llvm] [WebAssembly] Introduce CodeGenPassBuilder (PR #208983)

[Aiden Grossman via llvm-commits]

boomanaiden154 wrote:

I haven't been putting in TODOs for GlobalISel. It will get done before this gets made the default (we need sufficient test coverage), but that's quite a ways off. I plan on posting an RFC soon to selectively opt specific targets into the NewPM by default but it needs cooperation from frontends. To really enable the NewPM I still need to port something like 250 more passes and fix a bunch of regressions.

https://github.com/llvm/llvm-project/pull/208983