Refactor AppDomain.IsAppXModel and a few other AppDomain methods (#21181)

Contributes to #21028

19 files changed, 102 insertions, 270 deletions

diff --git a/src/System.Private.CoreLib/System.Private.CoreLib.csproj b/src/System.Private.CoreLib/System.Private.CoreLib.csproj
index 88f9062199..ca7e85f5e9 100644
--- a/src/System.Private.CoreLib/System.Private.CoreLib.csproj
+++ b/src/System.Private.CoreLib/System.Private.CoreLib.csproj
@@ -483,6 +483,7 @@
   </ItemGroup>
   <ItemGroup Condition="'$(TargetsWindows)' == 'true'">
     <Compile Include="$(BclSourcesRoot)\Interop\Windows\Kernel32\Interop.GetSystemDirectoryW.cs" />
+    <Compile Include="$(BclSourcesRoot)\System\ApplicationModel.Windows.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Diagnostics\DebugProvider.Windows.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Globalization\CultureInfo.Windows.cs" />
     <Compile Include="$(BclSourcesRoot)\System\Globalization\GlobalizationMode.Windows.cs" />
diff --git a/src/System.Private.CoreLib/src/System/AppDomain.cs b/src/System.Private.CoreLib/src/System/AppDomain.cs
index c1c74d097d..53a26f52ac 100644
--- a/src/System.Private.CoreLib/src/System/AppDomain.cs
+++ b/src/System.Private.CoreLib/src/System/AppDomain.cs
@@ -104,37 +104,6 @@ namespace System
 
         private IntPtr _pDomain;                      // this is an unmanaged pointer (AppDomain * m_pDomain)` used from the VM.
 
-#if FEATURE_APPX
-        private static APPX_FLAGS s_flags;
-
-        //
-        // Keep in async with vm\appdomainnative.cpp
-        //
-        [Flags]
-        private enum APPX_FLAGS
-        {
-            APPX_FLAGS_INITIALIZED = 0x01,
-
-            APPX_FLAGS_APPX_MODEL = 0x02,
-        }
-
-        private static APPX_FLAGS Flags
-        {
-            get
-            {
-                if (s_flags == 0)
-                    s_flags = nGetAppXFlags();
-
-                Debug.Assert(s_flags != 0);
-                return s_flags;
-            }
-        }
-
-        [DllImport(JitHelpers.QCall, CharSet = CharSet.Unicode)]
-        [return: MarshalAs(UnmanagedType.I4)]
-        private static extern APPX_FLAGS nGetAppXFlags();
-#endif
-
         /// <summary>
         ///     If this AppDomain is configured to have an AppDomain manager then create the instance of it.
         ///     This method is also called from the VM to create the domain manager in the default domain.
@@ -152,66 +121,9 @@ namespace System
             }
         }
 
-        /// <summary>
-        ///     Returns whether the current AppDomain follows the AppX rules.
-        /// </summary>
-        [Pure]
-        internal static bool IsAppXModel()
-        {
-#if FEATURE_APPX
-            return (Flags & APPX_FLAGS.APPX_FLAGS_APPX_MODEL) != 0;
-#else
-            return false;
-#endif
-        }
-
-        /// <summary>
-        ///     Checks (and throws on failure) if the domain supports Assembly.LoadFrom.
-        /// </summary>
-        [Pure]
-        internal static void CheckLoadFromSupported()
-        {
-#if FEATURE_APPX
-            if (IsAppXModel())
-                throw new NotSupportedException(SR.Format(SR.NotSupported_AppX, "Assembly.LoadFrom"));
-#endif
-        }
-
-        /// <summary>
-        ///     Checks (and throws on failure) if the domain supports Assembly.LoadFile.
-        /// </summary>
-        [Pure]
-        internal static void CheckLoadFileSupported()
-        {
-#if FEATURE_APPX
-            if (IsAppXModel())
-                throw new NotSupportedException(SR.Format(SR.NotSupported_AppX, "Assembly.LoadFile"));
-#endif
-        }
-
-        /// <summary>
-        ///     Checks (and throws on failure) if the domain supports Assembly.Load(byte[] ...).
-        /// </summary>
-        [Pure]
-        internal static void CheckLoadByteArraySupported()
-        {
-#if FEATURE_APPX
-            if (IsAppXModel())
-                throw new NotSupportedException(SR.Format(SR.NotSupported_AppX, "Assembly.Load(byte[], ...)"));
-#endif
-        }
-
         public static AppDomain CurrentDomain => Thread.GetDomain();
 
         [MethodImpl(MethodImplOptions.InternalCall)]
-        private extern Assembly[] nGetAssemblies(bool forIntrospection);
-
-        internal Assembly[] GetAssemblies(bool forIntrospection)
-        {
-            return nGetAssemblies(forIntrospection);
-        }
-
-        [MethodImpl(MethodImplOptions.InternalCall)]
         internal static extern void PublishAnonymouslyHostedDynamicMethodsAssembly(RuntimeAssembly assemblyHandle);
 
         [Obsolete("AppDomain.GetCurrentThreadId has been deprecated because it does not provide a stable Id when managed threads are running on fibers (aka lightweight threads). To get a stable identifier for a managed thread, use the ManagedThreadId property on Thread.  http://go.microsoft.com/fwlink/?linkid=14202", false)]
@@ -418,12 +330,6 @@ namespace System
         [MethodImpl(MethodImplOptions.InternalCall)]
         private extern void nSetupFriendlyName(string friendlyName);
 
-        [MethodImpl(MethodImplOptions.InternalCall)]
-        internal extern string IsStringInterned(string str);
-
-        [MethodImpl(MethodImplOptions.InternalCall)]
-        internal extern string GetOrInternString(string str);
-
         public int Id => GetId();
 
         [MethodImpl(MethodImplOptions.InternalCall)]
diff --git a/src/System.Private.CoreLib/src/System/ApplicationModel.Windows.cs b/src/System.Private.CoreLib/src/System/ApplicationModel.Windows.cs
new file mode 100644
index 0000000000..ea1e017424
--- /dev/null
+++ b/src/System.Private.CoreLib/src/System/ApplicationModel.Windows.cs
@@ -0,0 +1,20 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace System
+{
+    internal static class ApplicationModel
+    {
+#if FEATURE_APPX
+        // Cache the value in readonly static that can be optimized out by the JIT
+        internal readonly static bool IsUap = IsAppXProcess();
+
+        [DllImport(JitHelpers.QCall, CharSet = CharSet.Unicode)]
+        private static extern bool IsAppXProcess();
+#endif
+    }
+}
diff --git a/src/System.Private.CoreLib/src/System/Environment.cs b/src/System.Private.CoreLib/src/System/Environment.cs
index a81805340d..e94f62c438 100644
--- a/src/System.Private.CoreLib/src/System/Environment.cs
+++ b/src/System.Private.CoreLib/src/System/Environment.cs
@@ -476,7 +476,7 @@ namespace System
                 return GetEnvironmentVariableCore(variable);
 
 #if FEATURE_WIN32_REGISTRY
-            if (AppDomain.IsAppXModel())
+            if (ApplicationModel.IsUap)
 #endif
             {
                 return null;
@@ -564,7 +564,7 @@ namespace System
         internal static IEnumerable<KeyValuePair<string, string>> EnumerateEnvironmentVariablesFromRegistry(EnvironmentVariableTarget target)
         {
 #if FEATURE_WIN32_REGISTRY
-            if (AppDomain.IsAppXModel())
+            if (ApplicationModel.IsUap)
 #endif
             {
                 // Without registry support we have nothing to return
@@ -640,7 +640,7 @@ namespace System
             }
 
 #if FEATURE_WIN32_REGISTRY
-            if (AppDomain.IsAppXModel())
+            if (ApplicationModel.IsUap)
 #endif
             {
                 // other targets ignored
diff --git a/src/System.Private.CoreLib/src/System/Exception.cs b/src/System.Private.CoreLib/src/System/Exception.cs
index 0b1d39f143..911b1c5f78 100644
--- a/src/System.Private.CoreLib/src/System/Exception.cs
+++ b/src/System.Private.CoreLib/src/System/Exception.cs
@@ -489,7 +489,7 @@ namespace System
             string tmpStackTraceString;
 
 #if FEATURE_APPX
-            if (AppDomain.IsAppXModel())
+            if (ApplicationModel.IsUap)
             {
                 // Call our internal GetStackTrace in AppX so we can parse the result should
                 // we need to strip file/line info from it to make it PII-free. Calling the
diff --git a/src/System.Private.CoreLib/src/System/Globalization/CultureInfo.Windows.cs b/src/System.Private.CoreLib/src/System/Globalization/CultureInfo.Windows.cs
index 107a08cf07..f354b1950f 100644
--- a/src/System.Private.CoreLib/src/System/Globalization/CultureInfo.Windows.cs
+++ b/src/System.Private.CoreLib/src/System/Globalization/CultureInfo.Windows.cs
@@ -127,7 +127,7 @@ namespace System.Globalization
             get
             {
 #if FEATURE_APPX
-                if (AppDomain.IsAppXModel())
+                if (ApplicationModel.IsUap)
                 {
                     CultureInfo culture = GetCultureInfoForUserPreferredLanguageInAppX();
                     if (culture != null)
@@ -160,9 +160,9 @@ namespace System.Globalization
                 {
                     throw new ArgumentNullException(nameof(value));
                 }
-                
+
 #if FEATURE_APPX
-                if (AppDomain.IsAppXModel())
+                if (ApplicationModel.IsUap)
                 {
                     if (SetCultureInfoForUserPreferredLanguageInAppX(value))
                     {
@@ -184,7 +184,7 @@ namespace System.Globalization
             get
             {
 #if FEATURE_APPX
-                if (AppDomain.IsAppXModel())
+                if (ApplicationModel.IsUap)
                 {
                     CultureInfo culture = GetCultureInfoForUserPreferredLanguageInAppX();
                     if (culture != null)
@@ -203,7 +203,7 @@ namespace System.Globalization
 
                 CultureInfo.VerifyCultureName(value, true);
 #if FEATURE_APPX
-                if (AppDomain.IsAppXModel())
+                if (ApplicationModel.IsUap)
                 {
                     if (SetCultureInfoForUserPreferredLanguageInAppX(value))
                     {
diff --git a/src/System.Private.CoreLib/src/System/Reflection/Assembly.CoreCLR.cs b/src/System.Private.CoreLib/src/System/Reflection/Assembly.CoreCLR.cs
index 4703b8b0d5..0414de5e2e 100644
--- a/src/System.Private.CoreLib/src/System/Reflection/Assembly.CoreCLR.cs
+++ b/src/System.Private.CoreLib/src/System/Reflection/Assembly.CoreCLR.cs
@@ -165,10 +165,14 @@ namespace System.Reflection
         public static Assembly Load(byte[] rawAssembly,
                                     byte[] rawSymbolStore)
         {
-            AppDomain.CheckLoadByteArraySupported();
-
             if (rawAssembly == null)
                 throw new ArgumentNullException(nameof(rawAssembly));
+
+#if FEATURE_APPX
+            if (ApplicationModel.IsUap)
+                throw new NotSupportedException(SR.Format(SR.NotSupported_AppX, "Assembly.Load(byte[], ...)"));
+#endif
+
             AssemblyLoadContext alc = new IndividualAssemblyLoadContext();
             MemoryStream assemblyStream = new MemoryStream(rawAssembly);
             MemoryStream symbolStream = (rawSymbolStore != null) ? new MemoryStream(rawSymbolStore) : null;
@@ -179,12 +183,14 @@ namespace System.Reflection
 
         public static Assembly LoadFile(string path)
         {
-            AppDomain.CheckLoadFileSupported();
-
-            Assembly result = null;
             if (path == null)
                 throw new ArgumentNullException(nameof(path));
 
+#if FEATURE_APPX
+            if (ApplicationModel.IsUap)
+                throw new NotSupportedException(SR.Format(SR.NotSupported_AppX, "Assembly.LoadFile"));
+#endif
+
             if (PathInternal.IsPartiallyQualified(path))
             {
                 throw new ArgumentException(SR.Argument_AbsolutePathRequired, nameof(path));
@@ -192,6 +198,7 @@ namespace System.Reflection
 
             string normalizedPath = Path.GetFullPath(path);
 
+            Assembly result = null;
             lock (s_loadfile)
             {
                 if (s_loadfile.TryGetValue(normalizedPath, out result))
diff --git a/src/System.Private.CoreLib/src/System/Reflection/Emit/AssemblyBuilder.cs b/src/System.Private.CoreLib/src/System/Reflection/Emit/AssemblyBuilder.cs
index 0203244c10..e35c8da89e 100644
--- a/src/System.Private.CoreLib/src/System/Reflection/Emit/AssemblyBuilder.cs
+++ b/src/System.Private.CoreLib/src/System/Reflection/Emit/AssemblyBuilder.cs
@@ -164,8 +164,7 @@ namespace System.Reflection.Emit
 
         #region Constructor
 
-        internal AssemblyBuilder(AppDomain domain,
-                                 AssemblyName name,
+        internal AssemblyBuilder(AssemblyName name,
                                  AssemblyBuilderAccess access,
                                  ref StackCrawlMark stackMark,
                                  IEnumerable<CustomAttributeBuilder> unsafeAssemblyAttributes)
@@ -193,10 +192,9 @@ namespace System.Reflection.Emit
                 assemblyAttributes = new List<CustomAttributeBuilder>(unsafeAssemblyAttributes);
             }
 
-            _internalAssemblyBuilder = (InternalAssemblyBuilder)nCreateDynamicAssembly(domain,
-                                                                                        name,
-                                                                                        ref stackMark,
-                                                                                        access);
+            _internalAssemblyBuilder = (InternalAssemblyBuilder)nCreateDynamicAssembly(name,
+                                                                                       ref stackMark,
+                                                                                       access);
 
             _assemblyData = new AssemblyBuilderData(_internalAssemblyBuilder, access);
 
@@ -261,8 +259,7 @@ namespace System.Reflection.Emit
 
 
         [MethodImplAttribute(MethodImplOptions.InternalCall)]
-        private static extern Assembly nCreateDynamicAssembly(AppDomain domain,
-                                                              AssemblyName name,
+        private static extern Assembly nCreateDynamicAssembly(AssemblyName name,
                                                               ref StackCrawlMark stackMark,
                                                               AssemblyBuilderAccess access);
 
@@ -277,8 +274,7 @@ namespace System.Reflection.Emit
             lock (typeof(AssemblyBuilderLock))
             {
                 // We can only create dynamic assemblies in the current domain
-                return new AssemblyBuilder(AppDomain.CurrentDomain,
-                                           name,
+                return new AssemblyBuilder(name,
                                            access,
                                            ref stackMark,
                                            unsafeAssemblyAttributes);
diff --git a/src/System.Private.CoreLib/src/System/Reflection/RuntimeAssembly.cs b/src/System.Private.CoreLib/src/System/Reflection/RuntimeAssembly.cs
index b43b0cc5ba..c0a8101355 100644
--- a/src/System.Private.CoreLib/src/System/Reflection/RuntimeAssembly.cs
+++ b/src/System.Private.CoreLib/src/System/Reflection/RuntimeAssembly.cs
@@ -329,10 +329,15 @@ namespace System.Reflection
             if (assemblyRef == null)
                 throw new ArgumentNullException(nameof(assemblyRef));
 
-            if (assemblyRef.CodeBase != null)
+#if FEATURE_APPX
+            if (ApplicationModel.IsUap)
             {
-                AppDomain.CheckLoadFromSupported();
+                if (assemblyRef.CodeBase != null)
+                {
+                    throw new NotSupportedException(SR.Format(SR.NotSupported_AppX, "Assembly.LoadFrom"));
+                }
             }
+#endif
 
             assemblyRef = (AssemblyName)assemblyRef.Clone();
             if (assemblyRef.ProcessorArchitecture != ProcessorArchitecture.None)
diff --git a/src/System.Private.CoreLib/src/System/Resources/ResourceManager.cs b/src/System.Private.CoreLib/src/System/Resources/ResourceManager.cs
index 7c94e121a8..9e4f463201 100644
--- a/src/System.Private.CoreLib/src/System/Resources/ResourceManager.cs
+++ b/src/System.Private.CoreLib/src/System/Resources/ResourceManager.cs
@@ -183,8 +183,6 @@ namespace System.Resources
         internal const string ResFileExtension = ".resources";
         internal const int ResFileExtensionLength = 10;
 
-        private static volatile bool s_IsAppXModel;
-
         [System.Security.DynamicSecurityMethod] // Methods containing StackCrawlMark local var has to be marked DynamicSecurityMethod
         private void Init()
         {
@@ -713,7 +711,7 @@ namespace System.Resources
             Debug.Assert(_bUsingModernResourceManagement);
             Debug.Assert(_WinRTResourceManager != null);
             Debug.Assert(_PRIonAppXInitialized);
-            Debug.Assert(AppDomain.IsAppXModel());
+            Debug.Assert(ApplicationModel.IsUap);
 
             if (stringName.Length == 0)
                 return null;
@@ -810,12 +808,8 @@ namespace System.Resources
             {
                 if (resourcesAssembly != typeof(object).Assembly) // We are not loading resources for mscorlib
                 {
-                    // Cannot load the WindowsRuntimeResourceManager when in a compilation process, since it
-                    // lives in System.Runtime.WindowsRuntime and only mscorlib may be loaded for execution.
-                    if (AppDomain.IsAppXModel())
+                    if (ApplicationModel.IsUap)
                     {
-                        s_IsAppXModel = true;
-
                         // If we have the type information from the ResourceManager(Type) constructor, we use it. Otherwise, we use BaseNameField.
                         string reswFilename = _locationInfo == null ? BaseNameField : _locationInfo.FullName;
 
@@ -928,7 +922,7 @@ namespace System.Resources
                 throw new ArgumentNullException(nameof(name));
 
 #if FEATURE_APPX
-            if (s_IsAppXModel)
+            if (ApplicationModel.IsUap)
             {
                 // If the caller explictily passed in a culture that was obtained by calling CultureInfo.CurrentUICulture,
                 // null it out, so that we re-compute it.  If we use modern resource lookup, we may end up getting a "better"
@@ -1037,7 +1031,7 @@ namespace System.Resources
                 throw new ArgumentNullException(nameof(name));
 
 #if FEATURE_APPX
-            if (s_IsAppXModel)
+            if (ApplicationModel.IsUap)
             {
                 // If the caller explictily passed in a culture that was obtained by calling CultureInfo.CurrentUICulture,
                 // null it out, so that we re-compute it based on the Win32 value and not the AppX language list value.
diff --git a/src/System.Private.CoreLib/src/System/Runtime/InteropServices/WindowsRuntime/WindowsRuntimeMarshal.cs b/src/System.Private.CoreLib/src/System/Runtime/InteropServices/WindowsRuntime/WindowsRuntimeMarshal.cs
index ad04b25dd2..b240b9bcc3 100644
--- a/src/System.Private.CoreLib/src/System/Runtime/InteropServices/WindowsRuntime/WindowsRuntimeMarshal.cs
+++ b/src/System.Private.CoreLib/src/System/Runtime/InteropServices/WindowsRuntime/WindowsRuntimeMarshal.cs
@@ -1125,7 +1125,7 @@ namespace System.Runtime.InteropServices.WindowsRuntime
         internal static bool ReportUnhandledError(Exception e)
         {
             // Only report to the WinRT global exception handler in modern apps
-            if (!AppDomain.IsAppXModel())
+            if (!ApplicationModel.IsUap)
             {
                 return false;
             }
diff --git a/src/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.cs b/src/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.cs
index 971b6a4f48..8158b3fbd4 100644
--- a/src/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.cs
+++ b/src/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.cs
@@ -134,10 +134,8 @@ namespace System.Runtime.Loader
         [DllImport(JitHelpers.QCall, CharSet = CharSet.Unicode)]
         private static extern void LoadFromPath(IntPtr ptrNativeAssemblyLoadContet, string ilPath, string niPath, ObjectHandleOnStack retAssembly);
 
-        public static Assembly[] GetLoadedAssemblies()
-        {
-            return AppDomain.CurrentDomain.GetAssemblies(false);
-        }
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        public static extern Assembly[] GetLoadedAssemblies();
 
         // These methods load assemblies into the current AssemblyLoadContext 
         // They may be used in the implementation of an AssemblyLoadContext derivation
diff --git a/src/System.Private.CoreLib/src/System/String.CoreCLR.cs b/src/System.Private.CoreLib/src/System/String.CoreCLR.cs
index e81db4717d..b4a5019b4e 100644
--- a/src/System.Private.CoreLib/src/System/String.CoreCLR.cs
+++ b/src/System.Private.CoreLib/src/System/String.CoreCLR.cs
@@ -74,6 +74,11 @@ namespace System
         [MethodImplAttribute(MethodImplOptions.InternalCall)]
         internal extern bool TryGetTrailByte(out byte data);
 
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        private extern string Intern();
+        [MethodImpl(MethodImplOptions.InternalCall)]
+        private extern string IsInterned();
+
         public static string Intern(string str)
         {
             if (str == null)
@@ -81,7 +86,7 @@ namespace System
                 throw new ArgumentNullException(nameof(str));
             }
 
-            return Thread.GetDomain().GetOrInternString(str);
+            return str.Intern();
         }
 
         public static string IsInterned(string str)
@@ -91,7 +96,7 @@ namespace System
                 throw new ArgumentNullException(nameof(str));
             }
 
-            return Thread.GetDomain().IsStringInterned(str);
+            return str.IsInterned();
         }
 
         // Copies the source String (byte buffer) to the destination IntPtr memory allocated with len bytes.
diff --git a/src/System.Private.CoreLib/src/System/Threading/SynchronizationContext.cs b/src/System.Private.CoreLib/src/System/Threading/SynchronizationContext.cs
index 7b7d06c10d..8cfd7ae387 100644
--- a/src/System.Private.CoreLib/src/System/Threading/SynchronizationContext.cs
+++ b/src/System.Private.CoreLib/src/System/Threading/SynchronizationContext.cs
@@ -152,7 +152,7 @@ namespace System.Threading
                 SynchronizationContext context = Thread.CurrentThread.SynchronizationContext;
 
 #if FEATURE_APPX
-                if (context == null && AppDomain.IsAppXModel())
+                if (context == null && ApplicationModel.IsUap)
                     context = GetWinRTContext();
 #endif
 
@@ -164,7 +164,7 @@ namespace System.Threading
         private static SynchronizationContext GetWinRTContext()
         {
             Debug.Assert(Environment.IsWinRTSupported);
-            Debug.Assert(AppDomain.IsAppXModel());
+            Debug.Assert(ApplicationModel.IsUap);
 
             //
             // We call into the VM to get the dispatcher.  This is because:
diff --git a/src/System.Private.CoreLib/src/System/__ComObject.cs b/src/System.Private.CoreLib/src/System/__ComObject.cs
index 509f7bbefb..167e40e821 100644
--- a/src/System.Private.CoreLib/src/System/__ComObject.cs
+++ b/src/System.Private.CoreLib/src/System/__ComObject.cs
@@ -33,7 +33,7 @@ namespace System
             // Only do the IStringable cast when running under AppX for better compat
             // Otherwise we could do a IStringable cast in classic apps which could introduce
             // a thread transition which would lead to deadlock.
-            if (AppDomain.IsAppXModel())
+            if (ApplicationModel.IsUap)
             {
                 // Check whether the type implements IStringable.
                 if (this is IStringable stringableType)
diff --git a/src/vm/appdomainnative.cpp b/src/vm/appdomainnative.cpp
index da78874c74..c2cc06a748 100644
--- a/src/vm/appdomainnative.cpp
+++ b/src/vm/appdomainnative.cpp
@@ -133,8 +133,7 @@ void QCALLTYPE AppDomainNative::SetupBindingPaths(__in_z LPCWSTR wszTrustedPlatf
     END_QCALL;
 }
 
-
-FCIMPL4(Object*, AppDomainNative::CreateDynamicAssembly, AppDomainBaseObject* refThisUNSAFE, AssemblyNameBaseObject* assemblyNameUNSAFE, StackCrawlMark* stackMark, INT32 access)
+FCIMPL3(Object*, AppDomainNative::CreateDynamicAssembly, AssemblyNameBaseObject* assemblyNameUNSAFE, StackCrawlMark* stackMark, INT32 access)
 {
     FCALL_CONTRACT;
 
@@ -145,7 +144,6 @@ FCIMPL4(Object*, AppDomainNative::CreateDynamicAssembly, AppDomainBaseObject* re
     //</TODO>
     CreateDynamicAssemblyArgs   args;
 
-    args.refThis                = (APPDOMAINREF)    refThisUNSAFE;
     args.assemblyName           = (ASSEMBLYNAMEREF) assemblyNameUNSAFE;
     args.loaderAllocator        = NULL;
 
@@ -154,9 +152,7 @@ FCIMPL4(Object*, AppDomainNative::CreateDynamicAssembly, AppDomainBaseObject* re
 
     HELPER_METHOD_FRAME_BEGIN_RET_PROTECT((CreateDynamicAssemblyArgsGC&)args);
 
-    AppDomain* pAppDomain = ValidateArg(args.refThis);
-
-    Assembly *pAssembly = Assembly::CreateDynamic(pAppDomain, &args);
+    Assembly *pAssembly = Assembly::CreateDynamic(GetAppDomain(), &args);
 
     refRetVal = (ASSEMBLYREF) pAssembly->GetExposedObject();
 
@@ -166,56 +162,39 @@ FCIMPL4(Object*, AppDomainNative::CreateDynamicAssembly, AppDomainBaseObject* re
 FCIMPLEND
 
 #ifdef FEATURE_APPX
-
-//
-// Keep in sync with bcl\system\appdomain.cs
-//
-enum
-{
-    APPX_FLAGS_INITIALIZED =        0x01,
-
-    APPX_FLAGS_APPX_MODEL =         0x02,
-};
-
 // static
-INT32 QCALLTYPE AppDomainNative::GetAppXFlags()
+BOOL QCALLTYPE AppDomainNative::IsAppXProcess()
 {
     QCALL_CONTRACT;
 
-    UINT32 flags = APPX_FLAGS_INITIALIZED;
+    BOOL result;
 
     BEGIN_QCALL;
 
-    if (AppX::IsAppXProcess())
-    {
-        flags |= APPX_FLAGS_APPX_MODEL;
-    }
+    result = AppX::IsAppXProcess();
 
     END_QCALL;
 
-    return flags;
+    return result;
 }
-
 #endif // FEATURE_APPX
 
-FCIMPL2(Object*, AppDomainNative::GetAssemblies, AppDomainBaseObject* refThisUNSAFE, CLR_BOOL forIntrospection);
+FCIMPL0(Object*, AppDomainNative::GetLoadedAssemblies)
 {
     FCALL_CONTRACT;
 
     struct _gc
     {
         PTRARRAYREF     AsmArray;
-        APPDOMAINREF    refThis;
     } gc;
 
     gc.AsmArray = NULL;
-    gc.refThis  = (APPDOMAINREF) refThisUNSAFE;
 
     HELPER_METHOD_FRAME_BEGIN_RET_PROTECT(gc);
 
     MethodTable * pAssemblyClass = MscorlibBinder::GetClass(CLASS__ASSEMBLY);
 
-    AppDomain * pApp = ValidateArg(gc.refThis);
+    AppDomain * pApp = GetAppDomain();
 
     // Allocate an array with as many elements as there are assemblies in this
     //  appdomain.  This will usually be correct, but there may be assemblies
@@ -294,22 +273,19 @@ FCIMPL1(INT32, AppDomainNative::GetId, AppDomainBaseObject* refThisUNSAFE)
 }
 FCIMPLEND
 
-FCIMPL2(Object*, AppDomainNative::IsStringInterned, AppDomainBaseObject* refThisUNSAFE, StringObject* pStringUNSAFE)
+FCIMPL1(Object*, AppDomainNative::IsStringInterned, StringObject* pStringUNSAFE)
 {
     FCALL_CONTRACT;
 
-    APPDOMAINREF    refThis     = (APPDOMAINREF)ObjectToOBJECTREF(refThisUNSAFE);
     STRINGREF       refString   = ObjectToSTRINGREF(pStringUNSAFE);
     STRINGREF*      prefRetVal  = NULL;
 
-    HELPER_METHOD_FRAME_BEGIN_RET_2(refThis, refString);
-
-    ValidateArg(refThis);
+    HELPER_METHOD_FRAME_BEGIN_RET_1(refString);
     
     if (refString == NULL)
         COMPlusThrow(kArgumentNullException, W("ArgumentNull_String"));
 
-    prefRetVal = refThis->GetDomain()->IsStringInterned(&refString);
+    prefRetVal = GetAppDomain()->IsStringInterned(&refString);
 
     HELPER_METHOD_FRAME_END();
 
@@ -320,22 +296,19 @@ FCIMPL2(Object*, AppDomainNative::IsStringInterned, AppDomainBaseObject* refThis
 }
 FCIMPLEND
 
-FCIMPL2(Object*, AppDomainNative::GetOrInternString, AppDomainBaseObject* refThisUNSAFE, StringObject* pStringUNSAFE)
+FCIMPL1(Object*, AppDomainNative::GetOrInternString, StringObject* pStringUNSAFE)
 {
     FCALL_CONTRACT;
 
     STRINGREF    refRetVal  = NULL;
-    APPDOMAINREF refThis    = (APPDOMAINREF) refThisUNSAFE;
     STRINGREF    pString    = (STRINGREF)    pStringUNSAFE;
 
-    HELPER_METHOD_FRAME_BEGIN_RET_2(refThis, pString);
-
-    ValidateArg(refThis);
+    HELPER_METHOD_FRAME_BEGIN_RET_1(pString);
 
     if (pString == NULL)
         COMPlusThrow(kArgumentNullException, W("ArgumentNull_String"));
 
-    STRINGREF* stringVal = refThis->GetDomain()->GetOrInternString(&pString);
+    STRINGREF* stringVal = GetAppDomain()->GetOrInternString(&pString);
     if (stringVal != NULL)
     {
         refRetVal = *stringVal;
@@ -346,65 +319,6 @@ FCIMPL2(Object*, AppDomainNative::GetOrInternString, AppDomainBaseObject* refThi
 }
 FCIMPLEND
 
-
-FCIMPL1(Object*, AppDomainNative::GetDynamicDir, AppDomainBaseObject* refThisUNSAFE)
-{
-    FCALL_CONTRACT;
-
-    STRINGREF    str        = NULL;
-    return OBJECTREFToObject(str);
-}
-FCIMPLEND
-
-FCIMPL2(StringObject*, AppDomainNative::nApplyPolicy, AppDomainBaseObject* refThisUNSAFE, AssemblyNameBaseObject* refAssemblyNameUNSAFE)
-{
-    FCALL_CONTRACT;
-
-    struct _gc
-    {
-        APPDOMAINREF    refThis;
-        ASSEMBLYNAMEREF assemblyName;
-        STRINGREF       rv;
-    } gc;
-
-    gc.refThis      = (APPDOMAINREF)refThisUNSAFE;
-    gc.assemblyName = (ASSEMBLYNAMEREF) refAssemblyNameUNSAFE;
-    gc.rv           = NULL;
-
-    HELPER_METHOD_FRAME_BEGIN_RET_PROTECT(gc);
-
-    AppDomain* pDomain;
-    pDomain = ValidateArg(gc.refThis);
-
-    if (gc.assemblyName == NULL)
-    {
-        COMPlusThrow(kArgumentNullException, W("ArgumentNull_AssemblyName"));
-    }
-    if( (gc.assemblyName->GetSimpleName() == NULL) )
-    {
-        COMPlusThrow(kArgumentException, W("Format_StringZeroLength"));
-    }
-    Thread *pThread = GetThread();
-    CheckPointHolder cph(pThread->m_MarshalAlloc.GetCheckpoint()); //hold checkpoint for autorelease
-
-    // Initialize spec
-    AssemblySpec spec;
-    spec.InitializeSpec(&(pThread->m_MarshalAlloc), 
-                        &gc.assemblyName,
-                        FALSE /*fIsStringized*/
-                       );
-
-    StackSString sDisplayName;
-
-    spec.GetFileOrDisplayName(0,sDisplayName);
-
-    gc.rv = StringObject::NewString(sDisplayName);
-
-    HELPER_METHOD_FRAME_END();
-    return (StringObject*)OBJECTREFToObject(gc.rv);
-}
-FCIMPLEND
-
 FCIMPL1(UINT32, AppDomainNative::GetAppDomainId, AppDomainBaseObject* refThisUNSAFE)
 {
     FCALL_CONTRACT;
@@ -611,5 +525,3 @@ FCIMPL0(INT64, AppDomainNative::GetLastSurvivedProcessMemorySize)
 }
 FCIMPLEND
 #endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
-
-
diff --git a/src/vm/appdomainnative.hpp b/src/vm/appdomainnative.hpp
index dc1b133d2d..464ced73e6 100644
--- a/src/vm/appdomainnative.hpp
+++ b/src/vm/appdomainnative.hpp
@@ -23,19 +23,12 @@ public:
     static AppDomain *ValidateArg(APPDOMAINREF pThis);
     static FCDECL2(void, SetupFriendlyName, AppDomainBaseObject* refThisUNSAFE, StringObject* strFriendlyNameUNSAFE);
 
-    static FCDECL4(Object*, CreateDynamicAssembly, AppDomainBaseObject* refThisUNSAFE, AssemblyNameBaseObject* assemblyNameUNSAFE, StackCrawlMark* stackMark, INT32 access);
-    static FCDECL2(Object*, GetAssemblies, AppDomainBaseObject* refThisUNSAFE, CLR_BOOL fForIntrospection); 
-    static FCDECL2(Object*, GetOrInternString, AppDomainBaseObject* refThisUNSAFE, StringObject* pStringUNSAFE);
-    static FCDECL1(void, CreateContext, AppDomainBaseObject *refThisUNSAFE);
+    static FCDECL3(Object*, CreateDynamicAssembly, AssemblyNameBaseObject* assemblyNameUNSAFE, StackCrawlMark* stackMark, INT32 access);
+    static FCDECL0(Object*, GetLoadedAssemblies);
+    static FCDECL1(Object*, GetOrInternString, StringObject* pStringUNSAFE);
     static void QCALLTYPE SetupBindingPaths(__in_z LPCWSTR wszTrustedPlatformAssemblies, __in_z LPCWSTR wszPlatformResourceRoots, __in_z LPCWSTR wszAppPaths, __in_z LPCWSTR wszAppNiPaths, __in_z LPCWSTR appLocalWinMD);
-    static FCDECL1(Object*, GetDynamicDir, AppDomainBaseObject* refThisUNSAFE);
     static FCDECL1(INT32, GetId, AppDomainBaseObject* refThisUNSAFE);
-    static FCDECL1(void, ForceToSharedDomain, Object* pObjectUNSAFE);
-    static FCDECL1(LPVOID,  GetFusionContext, AppDomainBaseObject* refThis);
-    static FCDECL2(Object*, IsStringInterned, AppDomainBaseObject* refThis, StringObject* pString);
-    static FCDECL3(void,    UpdateContextProperty, LPVOID fusionContext, StringObject* key, Object* value);
-    static FCDECL2(StringObject*, nApplyPolicy, AppDomainBaseObject* refThisUNSAFE, AssemblyNameBaseObject* assemblyNameUNSAFE);
-    static FCDECL2(FC_BOOL_RET, IsFrameworkAssembly, AppDomainBaseObject* refThisUNSAFE, AssemblyNameBaseObject* refAssemblyNameUNSAFE);
+    static FCDECL1(Object*, IsStringInterned, StringObject* pString);
     static FCDECL1(UINT32,  GetAppDomainId, AppDomainBaseObject* refThisUNSAFE);
     static FCDECL1(void , PublishAnonymouslyHostedDynamicMethodsAssembly, AssemblyBaseObject * pAssemblyUNSAFE);
     static void QCALLTYPE SetNativeDllSearchDirectories(__in_z LPCWSTR wszAssembly);
@@ -49,15 +42,9 @@ public:
     static FCDECL0(INT64, GetLastSurvivedProcessMemorySize);
 #endif // FEATURE_APPDOMAIN_RESOURCE_MONITORING
 
-private:
-    static INT32 ExecuteAssemblyHelper(Assembly* pAssembly,
-                                       BOOL bCreatedConsole,
-                                       PTRARRAYREF *pStringArgs);
-
-public:
 #ifdef FEATURE_APPX
     static
-    INT32 QCALLTYPE GetAppXFlags();
+    INT32 QCALLTYPE IsAppXProcess();
 #endif
 };
 
diff --git a/src/vm/assembly.hpp b/src/vm/assembly.hpp
index cd34c707f2..d55d31e88c 100644
--- a/src/vm/assembly.hpp
+++ b/src/vm/assembly.hpp
@@ -57,7 +57,6 @@ class FriendAssemblyDescriptor;
 
 struct CreateDynamicAssemblyArgsGC
 {
-    APPDOMAINREF    refThis;
     ASSEMBLYNAMEREF assemblyName;
     LOADERALLOCATORREF loaderAllocator;
 };
diff --git a/src/vm/ecalllist.h b/src/vm/ecalllist.h
index b056eb9e91..5ee6173137 100644
--- a/src/vm/ecalllist.h
+++ b/src/vm/ecalllist.h
@@ -112,6 +112,8 @@ FCFuncStart(gStringFuncs)
     FCFuncElement("IsAscii", COMString::IsAscii)
     FCFuncElement("SetTrailByte", COMString::FCSetTrailByte)
     FCFuncElement("TryGetTrailByte", COMString::FCTryGetTrailByte)
+    FCFuncElement("IsInterned", AppDomainNative::IsStringInterned)
+    FCFuncElement("Intern", AppDomainNative::GetOrInternString)
 FCFuncEnd()
 
 FCFuncStart(gValueTypeFuncs)
@@ -432,22 +434,13 @@ FCFuncStart(gCOMClassWriter)
     QCFuncElement("DefineCustomAttribute", COMDynamicWrite::DefineCustomAttribute)
 FCFuncEnd()
 
-
 FCFuncStart(gCompatibilitySwitchFuncs)
     FCFuncElement("GetValueInternalCall", CompatibilitySwitch::GetValue)
 FCFuncEnd()
 
-
 FCFuncStart(gAppDomainFuncs)
-    FCFuncElement("IsStringInterned", AppDomainNative::IsStringInterned)
-
-#ifdef FEATURE_APPX
-    QCFuncElement("nGetAppXFlags", AppDomainNative::GetAppXFlags)
-#endif
     FCFuncElement("nSetupFriendlyName", AppDomainNative::SetupFriendlyName)
-    FCFuncElement("nGetAssemblies", AppDomainNative::GetAssemblies)
     FCFuncElement("GetId", AppDomainNative::GetId)
-    FCFuncElement("GetOrInternString", AppDomainNative::GetOrInternString)
     QCFuncElement("nSetupBindingPaths", AppDomainNative::SetupBindingPaths)
     QCFuncElement("nSetNativeDllSearchDirectories", AppDomainNative::SetNativeDllSearchDirectories)
     FCFuncElement("PublishAnonymouslyHostedDynamicMethodsAssembly", AppDomainNative::PublishAnonymouslyHostedDynamicMethodsAssembly)
@@ -462,6 +455,11 @@ FCFuncStart(gAppDomainFuncs)
 #endif //FEATURE_APPDOMAIN_RESOURCE_MONITORING
 FCFuncEnd()
 
+#ifdef FEATURE_APPX
+FCFuncStart(gApplicationModelFuncs)
+    QCFuncElement("IsAppXProcess", AppDomainNative::IsAppXProcess)
+FCFuncEnd()
+#endif
 
 FCFuncStart(gMdUtf8String)
     FCFuncElement("EqualsCaseSensitive", MdUtf8String::EqualsCaseSensitive)
@@ -542,6 +540,7 @@ FCFuncStart(gAssemblyLoadContextFuncs)
     QCFuncElement("InternalLoadUnmanagedDllFromPath", AssemblyNative::InternalLoadUnmanagedDllFromPath)
     QCFuncElement("LoadFromStream", AssemblyNative::LoadFromStream)
     QCFuncElement("GetLoadContextForAssembly", AssemblyNative::GetLoadContextForAssembly)
+    FCFuncElement("GetLoadedAssemblies", AppDomainNative::GetLoadedAssemblies)
 #if defined(FEATURE_MULTICOREJIT)
     QCFuncElement("InternalSetProfileRoot", MultiCoreJITNative::InternalSetProfileRoot)
     QCFuncElement("InternalStartProfile",   MultiCoreJITNative::InternalStartProfile)
@@ -1239,6 +1238,9 @@ FCFuncEnd()
 // The sorting is case-sensitive
 
 FCClassElement("AppDomain", "System", gAppDomainFuncs)
+#ifdef FEATURE_APPX
+FCClassElement("ApplicationModel", "System", gApplicationModelFuncs)
+#endif
 FCClassElement("ArgIterator", "System", gVarArgFuncs)
 FCClassElement("Array", "System", gArrayFuncs)
 FCClassElement("ArrayWithOffset", "System.Runtime.InteropServices", gArrayWithOffsetFuncs)