[CodeView] Mark this pointers as const.

This is for compatibility with MSVC, which also marks this pointers
as being const-qualified.

Fixes llvm.org/pr36526

Differential Revision: https://reviews.llvm.org/D54736

llvm-svn: 347353
diff --git a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
index 3b1fd76..59056b0 100644
--- a/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp
@@ -1715,6 +1715,9 @@
     break;
   }
 
+  if (Ty->isObjectPointer())
+    PO |= PointerOptions::Const;
+
   PointerRecord PR(PointeeTI, PK, PM, PO, Ty->getSizeInBits() / 8);
   return TypeTable.writeLeafType(PR);
 }