diff --git a/dlls/msvcp90/cxx.h b/dlls/msvcp90/cxx.h
index 5052f433875..0c5b83f93f6 100644
--- a/dlls/msvcp90/cxx.h
+++ b/dlls/msvcp90/cxx.h
@@ -46,7 +46,7 @@
 
 #ifndef __x86_64__
 
-#define DEFINE_RTTI_DATA(name, off, base_classes_no, cl1, cl2, cl3, cl4, cl5, cl6, cl7, cl8, cl9, mangled_name) \
+#define DEFINE_RTTI_BASE(name, base_classes_no, mangled_name) \
     static type_info name ## _type_info = { \
         &MSVCP_type_info_vtable, \
         NULL, \
@@ -58,7 +58,10 @@ static const rtti_base_descriptor name ## _rtti_base_descriptor = { \
     base_classes_no, \
     { 0, -1, 0}, \
     64 \
-}; \
+};
+
+#define DEFINE_RTTI_DATA(name, off, base_classes_no, cl1, cl2, cl3, cl4, cl5, cl6, cl7, cl8, cl9, mangled_name) \
+    DEFINE_RTTI_BASE(name, base_classes_no, mangled_name) \
 \
 static const rtti_base_array name ## _rtti_base_array = { \
     { \
@@ -122,7 +125,7 @@ static const cxx_exception_type type ## _cxx_type = { \
 
 #else
 
-#define DEFINE_RTTI_DATA(name, off, base_classes_no, cl1, cl2, cl3, cl4, cl5, cl6, cl7, cl8, cl9, mangled_name) \
+#define __DEFINE_RTTI_BASE(name, base_classes_no, mangled_name) \
     static type_info name ## _type_info = { \
         &MSVCP_type_info_vtable, \
         NULL, \
@@ -134,7 +137,18 @@ static rtti_base_descriptor name ## _rtti_base_descriptor = { \
     base_classes_no, \
     { 0, -1, 0}, \
     64 \
-}; \
+};
+
+#define DEFINE_RTTI_BASE(name, base_classes_no, mangled_name) \
+    __DEFINE_RTTI_BASE(name, base_classes_no, mangled_name) \
+    \
+    static void init_ ## name ## _rtti(char *base) \
+    { \
+        name ## _rtti_base_descriptor.type_descriptor = (char*)&name ## _type_info - base; \
+    }
+
+#define DEFINE_RTTI_DATA(name, off, base_classes_no, cl1, cl2, cl3, cl4, cl5, cl6, cl7, cl8, cl9, mangled_name) \
+    __DEFINE_RTTI_BASE(name, base_classes_no, mangled_name) \
 \
 static rtti_base_array name ## _rtti_base_array = { \
     { \