[llvm] [mlir] Split the llvm::ThreadPool into an abstract base class and an implementation (PR #82094)

[Mehdi Amini via llvm-commits]

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@@ -227,7 +265,7 @@ class ThreadPool {
 class ThreadPoolTaskGroup {
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joker-eph wrote:

In this PR, I'm not adding any new functionality or changing the contract of the pool with respect to its users. The only change is the ability to substitue the pool implementation itself, so I rather keep it at this.

But also in general I would keep this kind of feature for when the need arise in LLVM to support this kind of things.
It seems a bit overly speculative to me that we'd need this right now, and also things like " refusing to enqueue a task if the group is already too busy" seems to impact the semantics of the API.
(and even the API signature: the API has to be able to "fail").



https://github.com/llvm/llvm-project/pull/82094