Extend EETypes with information about generic composition (#1171)

In CoreRT we will not be using the `GenericInstanceDesc` mechanism from
Redhawk/Project N. Instead, generic composition (the generic type
definition, generic type arguments, arity, and variance) will be
directly available from the EEType by following two new rare fields.

The rare fields being added:
* `ETF_GenericDefinition`: pointer to the EEType of the generic type
definition
* `ETF_GenericComposition`: pointer to a variable sized stream of data
with the following grammar: ARITY | GENERIC_TYPE_ARGUMENT+ |
GENERIC_VARIANCE*. Generic variance is present only when
GenericVarianceFlag is set on the EEType.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/Native/Runtime/RuntimeInstance.cpp b/src/Native/Runtime/RuntimeInstance.cpp
index 251e060c7..0bfcc723f 100644
--- a/src/Native/Runtime/RuntimeInstance.cpp
+++ b/src/Native/Runtime/RuntimeInstance.cpp
@@ -796,10 +796,20 @@ COOP_PINVOKE_HELPER(EEType *, RhGetGenericInstantiation, (EEType *
                                                           EEType ***             ppInstantiation,
                                                           GenericVarianceType ** ppVarianceInfo))
 {
+#if CORERT
+    *pArity = pEEType->get_GenericArity();
+    *ppInstantiation = pEEType->get_GenericArguments();
+    if (pEEType->HasGenericVariance())
+        *ppVarianceInfo = pEEType->get_GenericVariance();
+    else
+        *ppVarianceInfo = NULL;
+    return pEEType->get_GenericDefinition();
+#else
     return GetRuntimeInstance()->GetGenericInstantiation(pEEType,
                                                          pArity,
                                                          ppInstantiation,
                                                          ppVarianceInfo);
+#endif
 }
 
 COOP_PINVOKE_HELPER(bool, RhSetGenericInstantiation, (EEType *               pEEType,