[llvm] [mlir] [MLIR] Add debug log to the pass manager (NFC) (PR #156205)

[Mehdi Amini via llvm-commits]

joker-eph wrote:

> It would be good to get an opinion from somebody from a different sub-project too (given that this is common code).

FYI: this code is exclusively used in MLIR right now, I've been tweaking this with Jacques for the last month :)

I'm actually revamping this patch soon with a different approach!

> Btw, a nit, [please avoid force-pushing](https://llvm.org/docs/GitHub.html#rebasing-pull-requests-and-force-pushes):

I'm not sure how to avoid this actually: any chain of work is unmanageable for me without this.



https://github.com/llvm/llvm-project/pull/156205