Refine the non-virtual this adjustments for thunks by using the offset
to the declaring class from the nearest virtual base class.  WIP.

llvm-svn: 94606
diff --git a/clang/lib/CodeGen/CGVtable.cpp b/clang/lib/CodeGen/CGVtable.cpp
index cb3f181..b6bb385 100644
--- a/clang/lib/CodeGen/CGVtable.cpp
+++ b/clang/lib/CodeGen/CGVtable.cpp
@@ -1114,6 +1114,12 @@
                   (int)VCalls[idx-1], MostDerivedClass->getNameAsCString()));
       }
       int64_t NonVirtualAdjustment = -VCallOffset[OGD];
+      QualType DerivedType = MD->getThisType(CGM.getContext());
+      QualType BaseType = cast<const CXXMethodDecl>(OGD.getDecl())->getThisType(CGM.getContext());
+      int64_t NonVirtualAdjustment2 = -(getNVOffset(BaseType, DerivedType)/8);
+      if (NonVirtualAdjustment2 != NonVirtualAdjustment) {
+        NonVirtualAdjustment = NonVirtualAdjustment2;
+      }
       int64_t VirtualAdjustment = 
         -((idx + extra + 2) * LLVMPointerWidth / 8);