Call ResolveSatelliteAssembly from native

Only call ResolveSatelliteAssembly from native when
resolving a satellite assembly

Author: sdmaclea

src/System.Private.CoreLib/shared/System/Runtime/Loader/AssemblyLoadContext.Unix.cs

@@ -66,7 +66,7 @@ public partial class AssemblyLoadContext
             return null;
         }
 
-        static private Assembly? ResolveSatelliteAssembly(AssemblyLoadContext alc, AssemblyName assemblyName)
+        private Assembly? ResolveSatelliteAssembly(AssemblyName assemblyName)
         {
             string? cultureName = assemblyName.CultureName;
 
@@ -78,7 +78,7 @@ public partial class AssemblyLoadContext
 
             AssemblyName parentAssemblyName = new AssemblyName(assemblyName.Name);
 
-            Assembly? parentAssembly = alc.LoadFromAssemblyName(parentAssemblyName);
+            Assembly? parentAssembly = LoadFromAssemblyName(parentAssemblyName);
 
             if (parentAssembly == null)
                 return null;

src/System.Private.CoreLib/shared/System/Runtime/Loader/AssemblyLoadContext.Windows.cs

@@ -10,7 +10,7 @@ namespace System.Runtime.Loader
 {
     public partial class AssemblyLoadContext
     {
-        static private Assembly? ResolveSatelliteAssembly(AssemblyLoadContext alc, AssemblyName assemblyName)
+        private Assembly? ResolveSatelliteAssembly(AssemblyName assemblyName)
         {
             string? cultureName = assemblyName.CultureName;
 
@@ -22,7 +22,7 @@ public partial class AssemblyLoadContext
 
             AssemblyName parentAssemblyName = new AssemblyName(assemblyName.Name);
 
-            Assembly? parentAssembly = alc.LoadFromAssemblyName(parentAssemblyName);
+            Assembly? parentAssembly = LoadFromAssemblyName(parentAssemblyName);
 
             if (parentAssembly == null)
                 return null;

src/System.Private.CoreLib/shared/System/Runtime/Loader/AssemblyLoadContext.cs

@@ -100,8 +100,6 @@ private protected AssemblyLoadContext(bool representsTPALoadContext, bool isColl
                 _id = s_nextId++;
                 s_allContexts.Add(_id, new WeakReference<AssemblyLoadContext>(this, true));
             }
-
-            Resolving += ResolveSatelliteAssembly;
         }
 
         ~AssemblyLoadContext()

src/System.Private.CoreLib/src/System/Runtime/Loader/AssemblyLoadContext.CoreCLR.cs

@@ -93,14 +93,24 @@ internal Assembly LoadFromInMemoryModule(IntPtr moduleHandle)
 
         // This method is invoked by the VM to resolve an assembly reference using the Resolving event
         // after trying assembly resolution via Load override and TPA load context without success.
-        private static Assembly ResolveUsingResolvingEvent(IntPtr gchManagedAssemblyLoadContext, AssemblyName assemblyName)
+        private static Assembly? ResolveUsingResolvingEvent(IntPtr gchManagedAssemblyLoadContext, AssemblyName assemblyName)
         {
             AssemblyLoadContext context = (AssemblyLoadContext)(GCHandle.FromIntPtr(gchManagedAssemblyLoadContext).Target)!;
 
             // Invoke the AssemblyResolve event callbacks if wired up
             return context.ResolveUsingEvent(assemblyName);
         }
 
+        // This method is invoked by the VM to resolve an assembly reference using the Resolving event
+        // after trying assembly resolution via Load override and TPA load context without success.
+        private static Assembly? ResolveSatelliteAssembly(IntPtr gchManagedAssemblyLoadContext, AssemblyName assemblyName)
+        {
+            AssemblyLoadContext context = (AssemblyLoadContext)(GCHandle.FromIntPtr(gchManagedAssemblyLoadContext).Target)!;
+
+            // Invoke the ResolveSatelliteAssembly method
+            return context.ResolveSatelliteAssembly(assemblyName);
+        }
+
         private Assembly? GetFirstResolvedAssembly(AssemblyName assemblyName)
         {
             Assembly? resolvedAssembly = null;

src/binder/clrprivbinderassemblyloadcontext.cpp

@@ -65,9 +65,10 @@ HRESULT CLRPrivBinderAssemblyLoadContext::BindAssemblyByName(IAssemblyName     *
         //
         // 1) Lookup the assembly within the LoadContext itself. If assembly is found, use it.
         // 2) Invoke the LoadContext's Load method implementation. If assembly is found, use it.
-        // 3) Lookup the assembly within TPABinder. If assembly is found, use it.
-        // 4) Invoke the LoadContext's Resolving event. If assembly is found, use it.
-        // 5) Raise exception.
+        // 3) Lookup the assembly within TPABinder (except for ssatellite requests). If assembly is found, use it.
+        // 4) Invoke the LoadContext's ResolveSatelliteAssembly method (for ssatellite requests). If assembly is found, use it.
+        // 5) Invoke the LoadContext's Resolving event. If assembly is found, use it.
+        // 6) Raise exception.
         //
         // This approach enables a LoadContext to override assemblies that have been loaded in TPA context by loading
         // a different (or even the same!) version.

src/vm/appdomain.cpp

@@ -6887,6 +6887,8 @@ HRESULT RuntimeInvokeHostAssemblyResolver(INT_PTR pManagedAssemblyLoadContextToB
             // Initialize the AssemblyName object from the AssemblySpec
             spec.AssemblyNameInit(&_gcRefs.oRefAssemblyName, NULL);
 
+            bool isSatelliteAssemblyRequest = (_gcRefs.oRefAssemblyName->GetCultureInfo() != NULL);
+
             if (!fInvokedForTPABinder)
             {
                 // Step 2 (of CLRPrivBinderAssemblyLoadContext::BindUsingAssemblyName) - Invoke Load method
@@ -6910,8 +6912,6 @@ HRESULT RuntimeInvokeHostAssemblyResolver(INT_PTR pManagedAssemblyLoadContextToB
                     fResolvedAssembly = true;
                 }
 
-                bool isSatelliteAssemblyRequest = (_gcRefs.oRefAssemblyName->GetCultureInfo() != NULL);
-
                 // Step 3 (of CLRPrivBinderAssemblyLoadContext::BindUsingAssemblyName)
                 if (!fResolvedAssembly && !isSatelliteAssemblyRequest)
                 {
@@ -6931,11 +6931,37 @@ HRESULT RuntimeInvokeHostAssemblyResolver(INT_PTR pManagedAssemblyLoadContextToB
                 }
             }
 
-            if (!fResolvedAssembly)
+            if (!fResolvedAssembly && isSatelliteAssemblyRequest)
             {
                 // Step 4 (of CLRPrivBinderAssemblyLoadContext::BindUsingAssemblyName)
                 //
                 // If we couldnt resolve the assembly using TPA LoadContext as well, then
+                // attempt to resolve it using the ResolveSatelliteAssembly method.
+                // Finally, setup arguments for invocation
+                BinderMethodID idHAR_ResolveUsingEvent = METHOD__ASSEMBLYLOADCONTEXT__RESOLVESATELLITEASSEMBLY;
+                MethodDescCallSite methLoadAssembly(idHAR_ResolveUsingEvent);
+
+                // Setup the arguments for the call
+                ARG_SLOT args[2] =
+                {
+                    PtrToArgSlot(pManagedAssemblyLoadContextToBindWithin), // IntPtr for managed assembly load context instance
+                    ObjToArgSlot(_gcRefs.oRefAssemblyName), // AssemblyName instance
+                };
+
+                // Make the call
+                _gcRefs.oRefLoadedAssembly = (ASSEMBLYREF) methLoadAssembly.Call_RetOBJECTREF(args);
+                if (_gcRefs.oRefLoadedAssembly != NULL)
+                {
+                    // Set the flag indicating we found the assembly
+                    fResolvedAssembly = true;
+                }
+            }
+
+            if (!fResolvedAssembly)
+            {
+                // Step 5 (of CLRPrivBinderAssemblyLoadContext::BindUsingAssemblyName)
+                //
+                // If we couldnt resolve the assembly using TPA LoadContext as well, then
                 // attempt to resolve it using the Resolving event.
                 // Finally, setup arguments for invocation
                 BinderMethodID idHAR_ResolveUsingEvent = METHOD__ASSEMBLYLOADCONTEXT__RESOLVEUSINGEVENT;

src/vm/mscorlib.h

@@ -899,9 +899,10 @@ DEFINE_FIELD_U(_state,                      AssemblyLoadContextBaseObject, _stat
 DEFINE_FIELD_U(_isCollectible,              AssemblyLoadContextBaseObject, _isCollectible)
 DEFINE_CLASS(ASSEMBLYLOADCONTEXT,  Loader,                AssemblyLoadContext)
 DEFINE_METHOD(ASSEMBLYLOADCONTEXT,  RESOLVE,          Resolve,                      SM_IntPtr_AssemblyName_RetAssemblyBase)
-DEFINE_METHOD(ASSEMBLYLOADCONTEXT,  RESOLVEUNMANAGEDDLL,          ResolveUnmanagedDll,                      SM_Str_IntPtr_RetIntPtr)
+DEFINE_METHOD(ASSEMBLYLOADCONTEXT,  RESOLVEUNMANAGEDDLL,           ResolveUnmanagedDll,           SM_Str_IntPtr_RetIntPtr)
 DEFINE_METHOD(ASSEMBLYLOADCONTEXT,  RESOLVEUNMANAGEDDLLUSINGEVENT, ResolveUnmanagedDllUsingEvent, SM_Str_AssemblyBase_IntPtr_RetIntPtr)
-DEFINE_METHOD(ASSEMBLYLOADCONTEXT,  RESOLVEUSINGEVENT,          ResolveUsingResolvingEvent,                      SM_IntPtr_AssemblyName_RetAssemblyBase)
+DEFINE_METHOD(ASSEMBLYLOADCONTEXT,  RESOLVEUSINGEVENT,             ResolveUsingResolvingEvent,    SM_IntPtr_AssemblyName_RetAssemblyBase)
+DEFINE_METHOD(ASSEMBLYLOADCONTEXT,  RESOLVESATELLITEASSEMBLY,      ResolveSatelliteAssembly,      SM_IntPtr_AssemblyName_RetAssemblyBase)
 DEFINE_FIELD(ASSEMBLYLOADCONTEXT,   ASSEMBLY_LOAD,          AssemblyLoad)
 DEFINE_METHOD(ASSEMBLYLOADCONTEXT,  ON_ASSEMBLY_LOAD,       OnAssemblyLoad, SM_Assembly_RetVoid)
 DEFINE_METHOD(ASSEMBLYLOADCONTEXT,  ON_RESOURCE_RESOLVE,    OnResourceResolve, SM_Assembly_Str_RetAssembly)