[llvm] [lit] Migrate lit to ProcessPoolExecutor (PR #202681)

[via llvm-commits]

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@@ -272,12 +269,22 @@ def run_tests(tests, lit_config, opts, discovered_tests):
     try:
         execute_in_tmp_dir(run, lit_config)
     except KeyboardInterrupt:
+        # Clear concurrent.futures thread registry to prevent atexit deadlocks.
+        try:
+            import concurrent.futures.process
+
+            if hasattr(concurrent.futures.process, "_threads_wakeups"):
+                concurrent.futures.process._threads_wakeups.clear()
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prasoon054 wrote:

Sure. I'll add the detailed comments here.

While writing this, I think we should move this logic to `run.py`'s abort handler next to the worker-kill code and keep `main.py` to simply setting `interrupted=True`.

https://github.com/llvm/llvm-project/pull/202681