From 234c733bde7e74c684d5b7423333007ab52c41ab Mon Sep 17 00:00:00 2001
From: Elinor Fung <elfung@microsoft.com>
Date: Thu, 12 Mar 2020 15:05:58 -0700
Subject: [PATCH] Check if global instance is registered

---
 .../Runtime/InteropServices/ComWrappers.cs    |  8 ++++
 .../InteropServices/Marshal.CoreCLR.cs        | 39 +++++++++++++------
 2 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/ComWrappers.cs b/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/ComWrappers.cs
index 731437a123009..6ac8a57a2001b 100644
--- a/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/ComWrappers.cs
+++ b/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/ComWrappers.cs
@@ -289,6 +289,14 @@ public void RegisterAsGlobalInstance()
             }
         }
 
+        /// <summary>
+        /// Get whether or not a global <see cref="ComWrappers" /> instance has been registered.
+        /// </summary>
+        internal static bool IsGlobalInstanceRegistered()
+        {
+            return s_globalInstance != null;
+        }
+
         /// <summary>
         /// Get the runtime provided IUnknown implementation.
         /// </summary>
diff --git a/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.CoreCLR.cs b/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.CoreCLR.cs
index 11b0fdf1241cb..b702d8bff8ed1 100644
--- a/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.CoreCLR.cs
+++ b/src/coreclr/src/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshal.CoreCLR.cs
@@ -331,10 +331,15 @@ public static string GetTypeInfoName(ITypeInfo typeInfo)
                 throw new ArgumentNullException(nameof(o));
             }
 
-            // Passing null as the ComWrapper implementation will use the globally registered wrappper (if available)
-            IntPtr ptrMaybe;
-            if (ComWrappers.TryGetOrCreateComInterfaceForObjectInternal(impl: null, o, CreateComInterfaceFlags.TrackerSupport, out ptrMaybe))
-                return ptrMaybe;
+            if (ComWrappers.IsGlobalInstanceRegistered())
+            {
+                // Passing null as the ComWrapper implementation will use the globally registered wrappper (if available)
+                IntPtr ptrMaybe;
+                if (ComWrappers.TryGetOrCreateComInterfaceForObjectInternal(impl: null, o, CreateComInterfaceFlags.TrackerSupport, out ptrMaybe))
+                {
+                    return ptrMaybe;
+                }
+            }
 
             return GetIUnknownForObjectNative(o, false);
         }
@@ -420,10 +425,15 @@ public static object GetObjectForIUnknown(IntPtr /* IUnknown* */ pUnk)
                 throw new ArgumentNullException(nameof(pUnk));
             }
 
-            // Passing null as the ComWrapper implementation will use the globally registered wrappper (if available)
-            object? objMaybe;
-            if (ComWrappers.TryGetOrCreateObjectForComInstanceInternal(impl: null, pUnk, CreateObjectFlags.TrackerObject, wrapperMaybe: null, out objMaybe))
-                return objMaybe!;
+            if (ComWrappers.IsGlobalInstanceRegistered())
+            {
+                // Passing null as the ComWrapper implementation will use the globally registered wrappper (if available)
+                object? objMaybe;
+                if (ComWrappers.TryGetOrCreateObjectForComInstanceInternal(impl: null, pUnk, CreateObjectFlags.TrackerObject, wrapperMaybe: null, out objMaybe))
+                {
+                    return objMaybe!;
+                }
+            }
 
             return GetObjectForIUnknownNative(pUnk);
         }
@@ -438,10 +448,15 @@ public static object GetUniqueObjectForIUnknown(IntPtr unknown)
                 throw new ArgumentNullException(nameof(unknown));
             }
 
-            // Passing null as the ComWrapper implementation will use the globally registered wrappper (if available)
-            object? objMaybe;
-            if (ComWrappers.TryGetOrCreateObjectForComInstanceInternal(impl: null, unknown, CreateObjectFlags.TrackerObject | CreateObjectFlags.UniqueInstance, wrapperMaybe: null, out objMaybe))
-                return objMaybe!;
+            if (ComWrappers.IsGlobalInstanceRegistered())
+            {
+                // Passing null as the ComWrapper implementation will use the globally registered wrappper (if available)
+                object? objMaybe;
+                if (ComWrappers.TryGetOrCreateObjectForComInstanceInternal(impl: null, unknown, CreateObjectFlags.TrackerObject | CreateObjectFlags.UniqueInstance, wrapperMaybe: null, out objMaybe))
+                {
+                    return objMaybe!;
+                }
+            }
 
             return GetUniqueObjectForIUnknownNative(unknown);
         }