[corlib] Link out more SR/SRE types (#18770)

* [corlib] Invoke TypeBuilderInstantiation.MakeGenericType through a delegate created in the TypeBuilder ctor to break a linker dependency between RuntimeType and TypeBuilderInstantiation.

* [corlib] Update linker descriptor.

* UnmanagedMarshal is not used from native code at all.
* AssemblyName is not used from native code at all.

3 files changed, 14 insertions, 16 deletions

diff --git a/mcs/class/corlib/LinkerDescriptor/mscorlib.xml b/mcs/class/corlib/LinkerDescriptor/mscorlib.xml
index cc06dbfe9e8..8768d2f3106 100644
--- a/mcs/class/corlib/LinkerDescriptor/mscorlib.xml
+++ b/mcs/class/corlib/LinkerDescriptor/mscorlib.xml
@@ -541,8 +541,6 @@
 		<!-- appdomain.c: ves_icall_System_AppDomain_GetAssemblies -->
 		<type fullname="System.Reflection.Assembly" preserve="fields"/>
 
-		<type fullname="System.Reflection.AssemblyName" preserve="fields" />
-		
 		<type fullname="System.Reflection.EventInfo" preserve="fields">
 			<method name="AddEventFrame" />
 			<method name="StaticAddEventAdapterFrame" />
@@ -656,10 +654,6 @@
 			<!-- reflection.c mono_reflection_call_is_assignable_to () -->
 			<method name="IsAssignableTo" feature="sre" />
 		</type>
-		<type fullname="System.Reflection.Emit.UnmanagedMarshal" preserve="fields" feature="sre" >
-			<method name="DefineCustom" feature="sre" />
-			<method name="DefineLPArrayInternal" feature="sre" />
-		</type>
 		<type fullname="System.Reflection.Emit.ArrayType" preserve="fields" feature="sre" />
 		<type fullname="System.Reflection.Emit.ByRefType" preserve="fields" feature="sre" />
 		<type fullname="System.Reflection.Emit.PointerType" preserve="fields" feature="sre" />
diff --git a/mcs/class/corlib/System.Reflection.Emit/TypeBuilder.cs b/mcs/class/corlib/System.Reflection.Emit/TypeBuilder.cs
index cc943475316..c2c6135bde3 100644
--- a/mcs/class/corlib/System.Reflection.Emit/TypeBuilder.cs
+++ b/mcs/class/corlib/System.Reflection.Emit/TypeBuilder.cs
@@ -120,8 +120,15 @@ namespace System.Reflection.Emit
 			return attrs;
 		}
 
+		TypeBuilder ()
+		{
+			// Use this delegate to avoid a linker dependency between RuntimeType and SRE code when SRE is not used
+			if (RuntimeType.MakeTypeBuilderInstantiation == null)
+				RuntimeType.MakeTypeBuilderInstantiation = System.Reflection.Emit.TypeBuilderInstantiation.MakeGenericType;
+		}
+
 		[PreserveDependency ("DoTypeBuilderResolve", "System.AppDomain")]
-		internal TypeBuilder (ModuleBuilder mb, TypeAttributes attr, int table_idx)
+		internal TypeBuilder (ModuleBuilder mb, TypeAttributes attr, int table_idx) : this ()
 		{
 			this.parent = null;
 			this.attrs = attr;
@@ -133,7 +140,7 @@ namespace System.Reflection.Emit
 			pmodule = mb;
 		}
 
-		internal TypeBuilder (ModuleBuilder mb, string name, TypeAttributes attr, Type parent, Type[] interfaces, PackingSize packing_size, int type_size, Type nesting_type)
+		internal TypeBuilder (ModuleBuilder mb, string name, TypeAttributes attr, Type parent, Type[] interfaces, PackingSize packing_size, int type_size, Type nesting_type) : this ()
 		{
 			int sep_index;
 			this.parent = ResolveUserType (parent);
diff --git a/mcs/class/referencesource/mscorlib/system/rttype.cs b/mcs/class/referencesource/mscorlib/system/rttype.cs
index 5184305c5aa..6e3ab286e89 100644
--- a/mcs/class/referencesource/mscorlib/system/rttype.cs
+++ b/mcs/class/referencesource/mscorlib/system/rttype.cs
@@ -4298,6 +4298,10 @@ namespace System
             return types;
         }
 
+        // Points to System.Reflection.Emit.TypeBuilderInstantiation.MakeGenericType
+        // Initialized when a TypeBuilder is created to avoid link-time SRE dependencies in this file
+        internal static Func<Type, Type[], Type> MakeTypeBuilderInstantiation;
+
         [System.Security.SecuritySafeCritical]  // auto-generated
         public override Type MakeGenericType(Type[] instantiation)
         {
@@ -4338,7 +4342,7 @@ namespace System
 #pragma warning disable 162
                     if (!RuntimeFeature.IsDynamicCodeSupported)
                         throw new PlatformNotSupportedException();
-                    return MakeTypeBuilderInstantiation(instantiation);
+                    return MakeTypeBuilderInstantiation(this, instantiation);
 #pragma warning restore 162
 #endif
                 }
@@ -4369,13 +4373,6 @@ namespace System
             return ret;
         }
 
-#if !NETCORE
-        Type MakeTypeBuilderInstantiation(Type[] instantiation)
-        {
-            return System.Reflection.Emit.TypeBuilderInstantiation.MakeGenericType(this, instantiation);
-        }
-#endif
-
         public override bool IsGenericTypeDefinition
         {
             get { return RuntimeTypeHandle.IsGenericTypeDefinition(this); }