[lld] [llvm] [DTLTO] Delay individual bitcode file serialization until after cache checks (PR #191142)

[Ben Dunbobbin via llvm-commits]

bd1976bris wrote:

> @bd1976bris This is an excellent idea - skip saving input bitcode archive members if the corresponding native object file has already been cached. However, implementing this feature in the refactored code is much less complex and takes only few lines of code.

@kbelochapka that sounds like good justification for refactoring. My understanding is that you have prepared a PR for this and will put it up shortly. It may be worth contrasting how easy it is to implement this optimization before and after the refactor for reviewers?

It seems worthwhile to implement any refactoring before introducing this optimization. Therefore, I will close this PR for now and we can reintroduce it once the question of refactoring is settled. Pinging @teresajohnson for visibility.

https://github.com/llvm/llvm-project/pull/191142