diff --git a/src/libraries/System.Private.CoreLib/src/System/AppDomain.cs b/src/libraries/System.Private.CoreLib/src/System/AppDomain.cs
index 7cd1e8e97a4e8..cd11786858904 100644
--- a/src/libraries/System.Private.CoreLib/src/System/AppDomain.cs
+++ b/src/libraries/System.Private.CoreLib/src/System/AppDomain.cs
@@ -7,6 +7,7 @@
 using System.Diagnostics;
 using System.IO;
 using System.Reflection;
+using System.Runtime.CompilerServices;
 using System.Runtime.ExceptionServices;
 using System.Runtime.Loader;
 using System.Runtime.Remoting;
@@ -386,6 +387,8 @@ public void SetThreadPrincipal(IPrincipal principal)
             return oh?.Unwrap();
         }
 
+        [PreserveDependency("GetDefaultInstance", "System.Security.Principal.GenericPrincipal", "System.Security.Claims")]
+        [PreserveDependency("GetDefaultInstance", "System.Security.Principal.WindowsPrincipal", "System.Security.Principal.Windows")]
         internal IPrincipal? GetThreadPrincipal()
         {
             IPrincipal? principal = _defaultPrincipal;
diff --git a/src/libraries/System.Security.Claims/src/ILLinkTrim.xml b/src/libraries/System.Security.Claims/src/ILLinkTrim_LibraryBuild.xml
similarity index 100%
rename from src/libraries/System.Security.Claims/src/ILLinkTrim.xml
rename to src/libraries/System.Security.Claims/src/ILLinkTrim_LibraryBuild.xml
diff --git a/src/libraries/System.Security.Principal.Windows/src/ILLinkTrim.xml b/src/libraries/System.Security.Principal.Windows/src/ILLinkTrim_LibraryBuild.xml
similarity index 100%
rename from src/libraries/System.Security.Principal.Windows/src/ILLinkTrim.xml
rename to src/libraries/System.Security.Principal.Windows/src/ILLinkTrim_LibraryBuild.xml