[llvm] [CodeGen] Fix `MachineModuleInfo`'s move constructor to be more safe with `MCContext` ownership. (PR #104834)

[Matin Raayai via llvm-commits]

matinraayai wrote:

> > @weiweichen @arsenm #105541 addresses the issues raised in the review here. If it proves challenging to merge due to `MCContext` management issues, we can merge only the first two items on the list regarding MMI's constructors. Let me know what you think.
> 
> @matinraayai, the changes in #105541 makes sense to me that it reflects the design change you suggested here as well. You did mention that the PR is WIP. I'm wondering how soon do you expect it, or at least the first 2 parts to get merged? (selfishness, I do really want the move constructor's bug fixed as soon as possible, either with a small patch or changing the way how MMI is used so that the move constructor is irrelevant with your PR 🙏)

The only reason I made it a WIP is because I'm not sure if everyone using the API like the changes or not (especially regarding the TargetMachine interface) + I might have forgotten to refactor parts of the LLVM monorepo that uses MMIs, or I may have broken something by accident. Once I get the green light that this change is favored, I will change it to a normal PR. The ETA is dependent on how long the codeowners will take to respond to it.


https://github.com/llvm/llvm-project/pull/104834