[clang] [clang][deps] Ensure the service outlives async module compiles (PR #181772)

[Aaron Ballman via cfe-commits]

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@@ -554,11 +555,42 @@ dependencies::initializeScanInstanceDependencyCollector(
   return MDC;
 }
 
+/// Manages (and terminates) the asynchronous compilation of modules.
+class AsyncModuleCompiles {
+  std::mutex Mutex;
+  bool Stop = false;
+  // FIXME: Have the service own a thread pool and use that instead.
+  std::vector<std::thread> Compiles;
+
+public:
+  /// Registers the module compilation, unless this instance is about to be
+  /// destroyed.
+  void add(llvm::unique_function<void()> Compile) {
+    std::lock_guard<std::mutex> Lock(Mutex);
+    if (!Stop)
+      Compiles.emplace_back(std::move(Compile));
+  }
+
+  ~AsyncModuleCompiles() {
----------------
AaronBallman wrote:

FWIW, I think this was [post-commit review feedback](https://llvm.org/docs/CodeReview.html#post-commit-review) we'd generally expect the patch author to address, particularly given the speed at which the PR was posted, accepted, and merged.

https://github.com/llvm/llvm-project/pull/181772