[llvm] [ORC] Fix synchronization in CoreAPIsTest. (PR #144556)

[Lang Hames via llvm-commits]

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@@ -1559,16 +1559,13 @@ TEST_F(CoreAPIsStandardTest, TestLookupWithThreadedMaterialization) {
 #if LLVM_ENABLE_THREADS
 
   std::mutex WorkThreadsMutex;
-  std::vector<std::thread> WorkThreads;
+  SmallVector<std::thread,0> WorkThreads;
   DispatchOverride = [&](std::unique_ptr<Task> T) {
-    std::promise<void> WaitP;
-    std::lock_guard<std::mutex> Lock(WorkThreadsMutex);
+    std::unique_lock Lock(WorkThreadsMutex);
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lhames wrote:

I think the movement is to scoped_lock over lock_guard, rather than to unique_lock.

I have a slight preference for making these kinds of cleanup (`std::vector` -> `SmallVector`, `lock_guard` -> `scoped_lock`) in a separate patch, so that the fix for the actual bug is as small as possible. This is a pretty small fix though, so as long as it's noted in the commit message doing the cleanup inline is probably ok.

https://github.com/llvm/llvm-project/pull/144556