Extract cleanup changes from #21793. (#21852)

* Cleanup changes from #21793.

* Emit the data pointer offset directly into the IL stream (and calculate it as needed instead of passing it through)

* Fix broken assumption that OverrideProcArgs::na::m_pMT is the array type instead of the element type (which it was).

1 files changed, 32 insertions, 4 deletions

diff --git a/src/vm/stubgen.h b/src/vm/stubgen.h
index 7bebfa7610..044029b0af 100644
--- a/src/vm/stubgen.h
+++ b/src/vm/stubgen.h
@@ -60,17 +60,26 @@ struct LocalDesc
 
     void MakeByRef()
     {
+        LIMITED_METHOD_CONTRACT;
         ChangeType(ELEMENT_TYPE_BYREF);
     }
 
     void MakePinned()
     {
+        LIMITED_METHOD_CONTRACT;
         ChangeType(ELEMENT_TYPE_PINNED);
     }
 
+    void MakeArray()
+    {
+        LIMITED_METHOD_CONTRACT;
+        ChangeType(ELEMENT_TYPE_SZARRAY);
+    }
+
     // makes the LocalDesc semantically equivalent to ET_TYPE_CMOD_REQD<IsCopyConstructed>/ET_TYPE_CMOD_REQD<NeedsCopyConstructorModifier>
     void MakeCopyConstructedPointer()
     {
+        LIMITED_METHOD_CONTRACT;
         ChangeType(ELEMENT_TYPE_PTR);
         bIsCopyConstructed = TRUE;
     }
@@ -96,22 +105,40 @@ struct LocalDesc
             THROWS;
             GC_TRIGGERS;
             MODE_ANY;
-            PRECONDITION(cbType == 1);    // this only works on 1-element types for now
         }
         CONTRACTL_END;
+
+        bool lastElementTypeIsValueType = false;
         
         if (ElementType[0] == ELEMENT_TYPE_VALUETYPE)
         {
-            return true;
+            lastElementTypeIsValueType = true;
         }
         else if ((ElementType[0] == ELEMENT_TYPE_INTERNAL) &&
                     (InternalToken.IsNativeValueType() ||
                      InternalToken.GetMethodTable()->IsValueType()))
         {
-            return true;
+            lastElementTypeIsValueType = true;
+        }
+
+        if (!lastElementTypeIsValueType)
+        {
+             return false;
+        }
+
+        // verify that the prefix element types don't make the type a non-value type
+        // this only works on LocalDescs with the prefixes exposed in the Add* methods above.
+        for (size_t i = 0; i < cbType - 1; i++)
+        {
+            if (ElementType[i] == ELEMENT_TYPE_BYREF
+                || ElementType[i] == ELEMENT_TYPE_SZARRAY
+                || ElementType[i] == ELEMENT_TYPE_PTR)
+            {
+                return false;
+            }
         }
 
-        return false;
+        return true;
     }
 };
 
@@ -595,6 +622,7 @@ public:
     void EmitLDC        (DWORD_PTR uConst);
     void EmitLDC_R4     (UINT32 uConst);
     void EmitLDC_R8     (UINT64 uConst);
+    void EmitLDELEMA    (int token);
     void EmitLDELEM_REF ();
     void EmitLDFLD      (int token);
     void EmitLDFLDA     (int token);