Fix type loader handling of __Canon in CoreRT

On Project N, `__Canon` is backed by an actual type in System.Private.CoreLib. In the new type system, we no longer need each type to have a token and we chose `__Canon` to be a synthetic type created out of thin air.

This poses a small problem when trying to refer to it from C#.

In this change:
* I'm making us not include `__Canon.cs` on CoreRT anymore.
* I'm updating the single method mode command line parser to parse `__Canon` specially. We were already special casing it by rewriting the type tree anyway (parse as an ECMA type and then replace). (This is what Project X uses in the bridging code too.)
* I'm making `GetCanonType` an intrinsic (which has access to the `__Canon` TypeDesc)
* Putting some code under ifdef that doesn't apply on CoreRT

[tfs-changeset: 1672488]

4 files changed, 9 insertions, 0 deletions

diff --git a/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/TypeBuilder.cs b/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/TypeBuilder.cs
index a23b0453b..7296204a0 100644
--- a/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/TypeBuilder.cs
+++ b/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/TypeBuilder.cs
@@ -505,9 +505,11 @@ namespace Internal.Runtime.TypeLoader
             // If so, use that, otherwise, run down the template type loader path with the universal template
             if ((state.TemplateType == null) || isTemplateUniversalCanon)
             {
+#if !CORERT
                 // CanonAlike types do not get dictionaries
                 if ((state.TemplateType == null) && (type.IsConstructedOverType(type.Context.CanonAlikeTypeArray)))
                     return;
+#endif
 
                 // ReadyToRun case - Native Layout is just the dictionary
                 NativeParser readyToRunInfoParser = state.GetParserForReadyToRunNativeLayoutInfo();
@@ -641,12 +643,14 @@ namespace Internal.Runtime.TypeLoader
                         TypeLoaderLogger.WriteLine("Found BagElementKind.DictionaryLayout");
                         Debug.Assert(!isTemplateUniversalCanon, "Universal template nativelayout do not have DictionaryLayout");
 
+#if !CORERT
                         if (type.IsConstructedOverType(type.Context.CanonAlikeTypeArray))
                         {
                             TypeLoaderLogger.WriteLine("Type is CanonAlike, skip generation of dictionary");
                             typeInfoParser.SkipInteger();
                             break;
                         }
+#endif
 
                         Debug.Assert(state.Dictionary == null);
                         if (!state.TemplateType.RetrieveRuntimeTypeHandleIfPossible())
diff --git a/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/genericdictionarycell.cs b/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/genericdictionarycell.cs
index 2ddeff53c..83a13d089 100644
--- a/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/genericdictionarycell.cs
+++ b/src/System.Private.TypeLoader/src/Internal/Runtime/TypeLoader/genericdictionarycell.cs
@@ -737,11 +737,13 @@ namespace Internal.Runtime.TypeLoader
 
                         bool methodRequestedIsCanonical = Method.IsCanonicalMethod(CanonicalFormKind.Specific);
                         MethodDesc canonAlikeForm;
+#if !CORERT
                         if (methodRequestedIsCanonical)
                         {
                             canonAlikeForm = Method.ReplaceTypesInConstructionOfMethod(Method.Context.CanonTypeArray, Method.Context.CanonAlikeTypeArray);
                         }
                         else
+#endif
                         {
                             canonAlikeForm = Method;
                         }
diff --git a/src/System.Private.TypeLoader/src/Internal/TypeSystem/CanonTypes.Runtime.cs b/src/System.Private.TypeLoader/src/Internal/TypeSystem/CanonTypes.Runtime.cs
index b7f4f5bc5..ce05945b4 100644
--- a/src/System.Private.TypeLoader/src/Internal/TypeSystem/CanonTypes.Runtime.cs
+++ b/src/System.Private.TypeLoader/src/Internal/TypeSystem/CanonTypes.Runtime.cs
@@ -5,6 +5,7 @@
 
 using System;
 
+using Internal.Runtime;
 using Internal.Runtime.Augments;
 
 namespace Internal.TypeSystem
diff --git a/src/System.Private.TypeLoader/src/Internal/TypeSystem/TypeSystemContext.Runtime.cs b/src/System.Private.TypeLoader/src/Internal/TypeSystem/TypeSystemContext.Runtime.cs
index 5ed63432f..75564a154 100644
--- a/src/System.Private.TypeLoader/src/Internal/TypeSystem/TypeSystemContext.Runtime.cs
+++ b/src/System.Private.TypeLoader/src/Internal/TypeSystem/TypeSystemContext.Runtime.cs
@@ -647,6 +647,7 @@ namespace Internal.TypeSystem
             _typesToFlushTypeSystemStateFrom = null;
         }
 
+#if !CORERT
         private TypeDesc _canonAlikeType;
 
         public TypeDesc CanonAlikeType
@@ -681,6 +682,7 @@ namespace Internal.TypeSystem
                 return _canonTypeArray;
             }
         }
+#endif
 
 #if ECMA_METADATA_SUPPORT
         public class ModuleToEcmaModuleHashtable : LockFreeReaderHashtable<EcmaModuleInfo, Internal.TypeSystem.Ecma.EcmaModule>