[PATCH] D86226: GlobalISel: Do not set observer of MachineIRBuilder in LegalizerHelper

[Aditya Nandakumar via Phabricator via llvm-commits]

aditya_nandakumar added a comment.

My thought on this Observer ownership is as follows (which I think I mentioned in another review).

- Each pass will setup an observer(wrapper) and install it to the MF. The MF at this point has the reference to the observer, and the pass owns each observer as it decides what it needs to observe and how.
- At the end of each pass, just reset the observer (there are RAII helpers for this).
- Remove the observer in MachineIRBuilder (is there a need for this?).
- No need to thread observer through APIs. Instead we get it through `MF.getObserver()`.

Thoughts?


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  https://reviews.llvm.org/D86226/new/

https://reviews.llvm.org/D86226