Remove or document Unsafe.AsPointer uses in core libraries

src/coreclr/nativeaot/Common/src/Internal/Runtime/CompilerHelpers/StartupCodeHelpers.cs

@@ -206,12 +206,13 @@ private static unsafe object[] InitializeStatics(IntPtr gcStaticRegionStart, int
                 nint blockAddr = MethodTable.SupportsRelativePointers ? (nint)ReadRelPtr32(pBlock) : *pBlock;
                 if ((blockAddr & GCStaticRegionConstants.Uninitialized) == GCStaticRegionConstants.Uninitialized)
                 {
-#pragma warning disable CS8500
                     object? obj = null;
+#pragma warning disable CS8500
                     RuntimeImports.RhAllocateNewObject(
                         new IntPtr(blockAddr & ~GCStaticRegionConstants.Mask),
                         (uint)GC_ALLOC_FLAGS.GC_ALLOC_PINNED_OBJECT_HEAP,
                         &obj);
+#pragma warning restore CS8500
                     if (obj == null)
                     {
                         RuntimeExceptionHelpers.FailFast("Failed allocating GC static bases");
@@ -233,8 +234,7 @@ private static unsafe object[] InitializeStatics(IntPtr gcStaticRegionStart, int
                     Unsafe.Add(ref rawSpineData, currentBase) = obj;
 
                     // Update the base pointer to point to the pinned object
-                    *pBlock = *(IntPtr*)&obj;
-#pragma warning restore CS8500
+                    *pBlock = Unsafe.GetPinnedObjectPointer(obj);
                 }
 
                 currentBase++;

src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/NativeRuntimeEventSource.Threading.NativeSinks.cs

@@ -94,7 +94,7 @@ private void ContentionLockCreated(nint LockID, nint AssociatedObjectID, ushort
 
         [NonEvent]
         [MethodImpl(MethodImplOptions.NoInlining)]
-        public void ContentionLockCreated(Lock lockObj) => ContentionLockCreated(lockObj.LockIdForEvents, lockObj.ObjectIdForEvents);
+        public void ContentionLockCreated(Lock lockObj) => ContentionLockCreated(lockObj.LockIdForEvents, Unsafe.ObjectIDForEvents(lockObj));
 
         [Event(81, Level = EventLevel.Informational, Message = Messages.ContentionStart, Task = Tasks.Contention, Opcode = EventOpcode.Start, Version = 2, Keywords = Keywords.ContentionKeyword)]
         private void ContentionStart(
@@ -115,7 +115,7 @@ public void ContentionStart(Lock lockObj) =>
                 ContentionFlagsMap.Managed,
                 DefaultClrInstanceId,
                 lockObj.LockIdForEvents,
-                lockObj.ObjectIdForEvents,
+                Unsafe.ObjectIDForEvents(lockObj),
                 lockObj.OwningThreadId);
 
         [Event(91, Level = EventLevel.Informational, Message = Messages.ContentionStop, Task = Tasks.Contention, Opcode = EventOpcode.Stop, Version = 1, Keywords = Keywords.ContentionKeyword)]
@@ -355,14 +355,12 @@ private void WaitHandleWaitStart(
             LogWaitHandleWaitStart(WaitSource, AssociatedObjectID, ClrInstanceID);
         }
 
-#pragma warning disable CS8500
         [NonEvent]
         [MethodImpl(MethodImplOptions.NoInlining)]
         public unsafe void WaitHandleWaitStart(
             WaitHandleWaitSourceMap waitSource = WaitHandleWaitSourceMap.Unknown,
             object? associatedObject = null) =>
-            WaitHandleWaitStart(waitSource, *(nint*)&associatedObject);
-#pragma warning restore CS8500
+            WaitHandleWaitStart(waitSource, Unsafe.ObjectIDForEvents(associatedObject));
 
         [Event(302, Level = EventLevel.Verbose, Message = Messages.WaitHandleWaitStop, Task = Tasks.WaitHandleWait, Opcode = EventOpcode.Stop, Version = 0, Keywords = Keywords.WaitHandleKeyword)]
         public void WaitHandleWaitStop(ushort ClrInstanceID = DefaultClrInstanceId)

src/libraries/System.Private.CoreLib/src/System/Diagnostics/Tracing/NativeRuntimeEventSource.Threading.cs

@@ -107,7 +107,7 @@ private unsafe void ContentionLockCreated(nint LockID, nint AssociatedObjectID,
 
         [NonEvent]
         [MethodImpl(MethodImplOptions.NoInlining)]
-        public void ContentionLockCreated(Lock lockObj) => ContentionLockCreated(lockObj.LockIdForEvents, lockObj.ObjectIdForEvents);
+        public void ContentionLockCreated(Lock lockObj) => ContentionLockCreated(lockObj.LockIdForEvents, Unsafe.ObjectIDForEvents(lockObj));
 
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:UnrecognizedReflectionPattern", Justification = "Parameters to this method are primitive and are trimmer safe")]
         [Event(81, Level = EventLevel.Informational, Message = Messages.ContentionStart, Task = Tasks.Contention, Opcode = EventOpcode.Start, Version = 2, Keywords = Keywords.ContentionKeyword)]
@@ -146,7 +146,7 @@ public void ContentionStart(Lock lockObj) =>
                 ContentionFlagsMap.Managed,
                 DefaultClrInstanceId,
                 lockObj.LockIdForEvents,
-                lockObj.ObjectIdForEvents,
+                Unsafe.ObjectIDForEvents(lockObj),
                 lockObj.OwningThreadId);
 
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:UnrecognizedReflectionPattern", Justification = "Parameters to this method are primitive and are trimmer safe")]
@@ -552,14 +552,12 @@ private unsafe void WaitHandleWaitStart(
             WriteEventCore(301, 3, data);
         }
 
-#pragma warning disable CS8500
         [NonEvent]
         [MethodImpl(MethodImplOptions.NoInlining)]
         public unsafe void WaitHandleWaitStart(
             WaitHandleWaitSourceMap waitSource = WaitHandleWaitSourceMap.Unknown,
             object? associatedObject = null) =>
-            WaitHandleWaitStart(waitSource, *(nint*)&associatedObject);
-#pragma warning restore CS8500
+            WaitHandleWaitStart(waitSource, Unsafe.ObjectIDForEvents(associatedObject));
 
         [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:UnrecognizedReflectionPattern", Justification = "Parameters to this method are primitive and are trimmer safe")]
         [Event(302, Level = EventLevel.Verbose, Message = Messages.WaitHandleWaitStop, Task = Tasks.WaitHandleWait, Opcode = EventOpcode.Stop, Version = 0, Keywords = Keywords.WaitHandleKeyword)]

src/libraries/System.Private.CoreLib/src/System/Runtime/CompilerServices/Unsafe.cs

@@ -935,5 +935,10 @@ internal static nuint OpportunisticMisalignment<T>(ref readonly T address, nuint
             Debug.Assert(nuint.IsPow2(alignment));
             return (nuint)AsPointer(ref AsRef(in address)) & (alignment - 1);
         }
+
+        // Returns the object as a IntPtr - safe when object is pinned, or when only used for logging;
+        // The second method is also defined so that safe usage is always obvious by name.
+        internal static nint GetPinnedObjectPointer(object o) =>  *(nint*)&o;
+        internal static nint ObjectIDForEvents(object o) => GetPinnedObjectPointer(o);
     }
 }

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

@@ -636,17 +636,6 @@ internal nint LockIdForEvents
             }
         }
 
-        internal unsafe nint ObjectIdForEvents
-        {
-            get
-            {
-                Lock lockObj = this;
-#pragma warning disable CS8500
-                return *(nint*)&lockObj;
-#pragma warning restore CS8500
-            }
-        }
-
         internal ulong OwningThreadId => _owningThreadId;
 
         private static short DetermineMaxSpinCount() =>