[codeview] Use a type index of zero for static method "this" types

Otherwise VS won't show anything in the autos or watch window of static
methods.

llvm-svn: 313329
diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 7e778c5..87aeb1f 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -1561,7 +1561,7 @@
     ReturnTypeIndex = ReturnAndArgTypesRef.front();
     ArgTypeIndices = ReturnAndArgTypesRef.drop_front();
   }
-  TypeIndex ThisTypeIndex = TypeIndex::Void();
+  TypeIndex ThisTypeIndex;
   if (!IsStaticMethod && !ArgTypeIndices.empty()) {
     ThisTypeIndex = ArgTypeIndices.front();
     ArgTypeIndices = ArgTypeIndices.drop_front();