Make RuntimeType sealed and deleted support for introspection only loads (#19427)

- Sealed Runtime makes `is RuntimeType` and similar checks faster. These checks are fairly common in reflection.
- Delete support for introspection only loads from the runtime. We do not plan to use in .NET Core. The support for introspection loads inherited from RuntimeType and thus it is incompatible with sealed RuntimeType.

1 files changed, 3 insertions, 40 deletions

diff --git a/src/vm/methodtable.cpp b/src/vm/methodtable.cpp
index aeb0c766f1..a768ded29b 100644
--- a/src/vm/methodtable.cpp
+++ b/src/vm/methodtable.cpp
@@ -4029,10 +4029,7 @@ OBJECTREF MethodTable::GetManagedClassObject()
 
         REFLECTCLASSBASEREF  refClass = NULL;
         GCPROTECT_BEGIN(refClass);
-        if (GetAssembly()->IsIntrospectionOnly())
-            refClass = (REFLECTCLASSBASEREF) AllocateObject(MscorlibBinder::GetClass(CLASS__CLASS_INTROSPECTION_ONLY));
-        else
-            refClass = (REFLECTCLASSBASEREF) AllocateObject(g_pRuntimeTypeClass);
+        refClass = (REFLECTCLASSBASEREF) AllocateObject(g_pRuntimeTypeClass);
 
         LoaderAllocator *pLoaderAllocator = GetLoaderAllocator();
 
@@ -5966,7 +5963,7 @@ void MethodTable::DoFullyLoad(Generics::RecursionGraph * const pVisited,  const
             SetIsDependenciesLoaded();
 
 #if defined(FEATURE_COMINTEROP) && !defined(DACCESS_COMPILE)
-            if (WinRTSupported() && g_fEEStarted && !ContainsIntrospectionOnlyTypes())
+            if (WinRTSupported() && g_fEEStarted)
             {
                 _ASSERTE(GetAppDomain() != NULL);
 
@@ -9367,7 +9364,7 @@ CHECK MethodTable::CheckActivated()
 }
 
 #ifdef _MSC_VER
-// Optimization intended for EnsureInstanceActive, IsIntrospectionOnly, EnsureActive only
+// Optimization intended for EnsureInstanceActive, EnsureActive only
 #pragma optimize("t", on)
 #endif // _MSC_VER
 //==========================================================================================
@@ -9423,40 +9420,6 @@ VOID MethodTable::EnsureInstanceActive()
 #endif //!DACCESS_COMPILE
 
 //==========================================================================================
-BOOL MethodTable::IsIntrospectionOnly()
-{
-    WRAPPER_NO_CONTRACT;
-    return GetAssembly()->IsIntrospectionOnly();
-}
-
-//==========================================================================================
-BOOL MethodTable::ContainsIntrospectionOnlyTypes()
-{
-    CONTRACTL
-    {
-        THROWS;
-        GC_TRIGGERS;
-        MODE_ANY;
-    }
-    CONTRACTL_END
-
-    // check this type
-    if (IsIntrospectionOnly())
-        return TRUE;
-
-    // check the instantiation
-    Instantiation inst = GetInstantiation();
-    for (DWORD i = 0; i < inst.GetNumArgs(); i++)
-    {
-        CONSISTENCY_CHECK(!inst[i].IsEncodedFixup());
-        if (inst[i].ContainsIntrospectionOnlyTypes())
-            return TRUE;
-    }
-
-    return FALSE;
-}
-
-//==========================================================================================
 #ifndef DACCESS_COMPILE
 VOID MethodTable::EnsureActive()
 {