[llvm] Reduce llvm-gsymutil memory usage (PR #91023)

[Kevin Frei via llvm-commits]

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@@ -658,6 +711,9 @@ void DWARFUnit::clearDIEs(bool KeepCUDie) {
   // It depends on the implementation whether the request is fulfilled.
   // Create a new vector with a small capacity and assign it to the DieArray to
   // have previous contents freed.
+  llvm::sys::ScopedWriter FreeLock(CUDieFreeMutex);
+  llvm::sys::ScopedWriter CULock(CUDieArrayMutex);
+  llvm::sys::ScopedWriter AllLock(AllDieArrayMutex);
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kevinfrei wrote:

I believe taking all 3 locks is overkill, as getting the CUDieFreeMutex writer lock will block until the CUDie and AllDie locks are free. Thoughts?

https://github.com/llvm/llvm-project/pull/91023