Fix class construction recursion issue in Lock on NativeAOT (#94241)

* Fix class construction recursion issue in `Lock` on NativeAOT

- The `Monitor` type was being constructed due to the use of `Monitor.DebugBlockingScope`, added that to the initialization phase
- If necessary, an alternative may be to move `DebugBlockingScope` to be under `Lock`. Based on the comments the thread-static field is apparently bound-to in debugging scenarios.
- Fixes #94227

* Remove `DebugBlockingScope` instead

src/coreclr/nativeaot/System.Private.CoreLib/src/Internal/Runtime/CompilerHelpers/SynchronizedMethodHelpers.cs

@@ -30,7 +30,7 @@ private static void MonitorEnter(object obj, ref bool lockTaken)
                 ObjectHeader.GetLockObject(obj) :
                 SyncTable.GetLockObject(resultOrIndex);
 
-            lck.TryEnterSlow(Timeout.Infinite, currentThreadID, obj);
+            lck.TryEnterSlow(Timeout.Infinite, currentThreadID);
             lockTaken = true;
         }
         private static void MonitorExit(object obj, ref bool lockTaken)
@@ -59,7 +59,7 @@ private static unsafe void MonitorEnterStatic(MethodTable* pMT, ref bool lockTak
                 ObjectHeader.GetLockObject(obj) :
                 SyncTable.GetLockObject(resultOrIndex);
 
-            lck.TryEnterSlow(Timeout.Infinite, currentThreadID, obj);
+            lck.TryEnterSlow(Timeout.Infinite, currentThreadID);
             lockTaken = true;
         }
         private static unsafe void MonitorExitStatic(MethodTable* pMT, ref bool lockTaken)

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Threading/Lock.NativeAot.cs

@@ -54,12 +54,8 @@ internal void Exit(int currentManagedThreadId)
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private ThreadId TryEnterSlow(int timeoutMs, ThreadId currentThreadId) =>
-            TryEnterSlow(timeoutMs, currentThreadId, this);
-
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        internal bool TryEnterSlow(int timeoutMs, int currentManagedThreadId, object associatedObject) =>
-            TryEnterSlow(timeoutMs, new ThreadId((uint)currentManagedThreadId), associatedObject).IsInitialized;
+        internal bool TryEnterSlow(int timeoutMs, int currentManagedThreadId) =>
+            TryEnterSlow(timeoutMs, new ThreadId((uint)currentManagedThreadId)).IsInitialized;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         internal bool GetIsHeldByCurrentThread(int currentManagedThreadId)

src/coreclr/nativeaot/System.Private.CoreLib/src/System/Threading/Monitor.NativeAot.cs

@@ -50,7 +50,7 @@ public static void Enter(object obj)
                 ObjectHeader.GetLockObject(obj) :
                 SyncTable.GetLockObject(resultOrIndex);
 
-            lck.TryEnterSlow(Timeout.Infinite, currentThreadID, obj);
+            lck.TryEnterSlow(Timeout.Infinite, currentThreadID);
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -82,7 +82,7 @@ public static bool TryEnter(object obj)
             if (currentThreadID != 0 && lck.TryEnterOneShot(currentThreadID))
                 return true;
 
-            return lck.TryEnterSlow(0, currentThreadID, obj);
+            return lck.TryEnterSlow(0, currentThreadID);
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -114,7 +114,7 @@ public static bool TryEnter(object obj, int millisecondsTimeout)
             if (millisecondsTimeout == 0 && currentThreadID != 0 && lck.TryEnterOneShot(currentThreadID))
                 return true;
 
-            return lck.TryEnterSlow(millisecondsTimeout, currentThreadID, obj);
+            return lck.TryEnterSlow(millisecondsTimeout, currentThreadID);
         }
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
@@ -146,12 +146,7 @@ public static bool IsEntered(object obj)
         [UnsupportedOSPlatform("browser")]
         public static bool Wait(object obj, int millisecondsTimeout)
         {
-            Condition condition = GetCondition(obj);
-
-            using (new DebugBlockingScope(obj, DebugBlockingItemType.MonitorEvent, millisecondsTimeout, out _))
-            {
-                return condition.Wait(millisecondsTimeout);
-            }
+            return GetCondition(obj).Wait(millisecondsTimeout);
         }
 
         public static void Pulse(object obj)
@@ -170,62 +165,6 @@ public static void PulseAll(object obj)
 
         #endregion
 
-        #region Debugger support
-
-        // The debugger binds to the fields below by name. Do not change any names or types without
-        // updating the debugger!
-
-        // The head of the list of DebugBlockingItem stack objects used by the debugger to implement
-        // ICorDebugThread4::GetBlockingObjects. Usually the list either is empty or contains a single
-        // item. However, a wait on an STA thread may reenter via the message pump and cause the thread
-        // to be blocked on a second object.
-        [ThreadStatic]
-        private static IntPtr t_firstBlockingItem;
-
-        // Different ways a thread can be blocked that the debugger will expose.
-        // Do not change or add members without updating the debugger code.
-        internal enum DebugBlockingItemType
-        {
-            MonitorCriticalSection = 0,
-            MonitorEvent = 1
-        }
-
-        // Represents an item a thread is blocked on. This structure is allocated on the stack and accessed by the debugger.
-        internal struct DebugBlockingItem
-        {
-            // The object the thread is waiting on
-            public object _object;
-
-            // Indicates how the thread is blocked on the item
-            public DebugBlockingItemType _blockingType;
-
-            // Blocking timeout in milliseconds or Timeout.Infinite for no timeout
-            public int _timeout;
-
-            // Next pointer in the linked list of DebugBlockingItem records
-            public IntPtr _next;
-        }
-
-        internal unsafe struct DebugBlockingScope : IDisposable
-        {
-            public DebugBlockingScope(object obj, DebugBlockingItemType blockingType, int timeout, out DebugBlockingItem blockingItem)
-            {
-                blockingItem._object = obj;
-                blockingItem._blockingType = blockingType;
-                blockingItem._timeout = timeout;
-                blockingItem._next = t_firstBlockingItem;
-
-                t_firstBlockingItem = (IntPtr)Unsafe.AsPointer(ref blockingItem);
-            }
-
-            public void Dispose()
-            {
-                t_firstBlockingItem = Unsafe.Read<DebugBlockingItem>((void*)t_firstBlockingItem)._next;
-            }
-        }
-
-        #endregion
-
         #region Metrics
 
         /// <summary>

src/libraries/System.Private.CoreLib/src/System/Threading/Lock.cs

@@ -290,11 +290,7 @@ private void ExitImpl()
         private static bool IsAdaptiveSpinEnabled(short minSpinCount) => minSpinCount <= 0;
 
         [MethodImpl(MethodImplOptions.NoInlining)]
-#if !NATIVEAOT
         private ThreadId TryEnterSlow(int timeoutMs, ThreadId currentThreadId)
-#else
-        private ThreadId TryEnterSlow(int timeoutMs, ThreadId currentThreadId, object associatedObject)
-#endif
         {
             Debug.Assert(timeoutMs >= -1);
 
@@ -462,15 +458,6 @@ private ThreadId TryEnterSlow(int timeoutMs, ThreadId currentThreadId, object as
             // exceptional paths.
             try
             {
-#if NATIVEAOT
-                using var debugBlockingScope =
-                    new Monitor.DebugBlockingScope(
-                        associatedObject,
-                        Monitor.DebugBlockingItemType.MonitorCriticalSection,
-                        timeoutMs,
-                        out _);
-#endif
-
                 Interlocked.Increment(ref s_contentionCount);
 
                 long waitStartTimeTicks = 0;