diff --git a/lib/CodeGen/CGRtti.cpp b/lib/CodeGen/CGRtti.cpp
index 8484e2d..3d76bcd 100644
--- a/lib/CodeGen/CGRtti.cpp
+++ b/lib/CodeGen/CGRtti.cpp
@@ -24,6 +24,25 @@
     : CGM(cgm), VMContext(cgm.getModule().getContext()),
       Int8PtrTy(llvm::Type::getInt8PtrTy(VMContext)) { }
 
+  llvm::Constant *Buildclass_type_infoDesc() {
+    // Build a descriptor for class_type_info.
+    llvm::StringRef Name = "_ZTVN10__cxxabiv121__vmi_class_type_infoE";
+    llvm::Constant *GV = CGM.getModule().getGlobalVariable(Name);
+    if (GV)
+      GV = llvm::ConstantExpr::getBitCast(GV,
+                                          llvm::PointerType::get(Int8PtrTy, 0));
+    else {
+      llvm::GlobalVariable::LinkageTypes linktype;
+      linktype = llvm::GlobalValue::ExternalLinkage;
+      GV = new llvm::GlobalVariable(CGM.getModule(), Int8PtrTy,
+                                    true, linktype, 0, Name);
+    }  
+    llvm::Constant *C;
+    C = llvm::ConstantInt::get(llvm::Type::getInt64Ty(VMContext), 2);
+    C = llvm::ConstantExpr::getInBoundsGetElementPtr(GV, &C, 1);
+    return llvm::ConstantExpr::getBitCast(C, Int8PtrTy);
+  }
+  
   llvm::Constant *BuildName(const CXXRecordDecl *RD) {
     llvm::SmallString<256> OutName;
     llvm::raw_svector_ostream Out(OutName);
@@ -42,36 +61,40 @@
     s = llvm::ConstantExpr::getBitCast(s, Int8PtrTy);
     return s;
   };
+
+  llvm::Constant *Buildclass_type_info(const CXXRecordDecl *RD) {
+    const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
+
+    if (!CGM.getContext().getLangOptions().Rtti)
+      return llvm::Constant::getNullValue(Int8PtrTy);
+
+    llvm::SmallString<256> OutName;
+    llvm::raw_svector_ostream Out(OutName);
+    mangleCXXRtti(CGM.getMangleContext(), CGM.getContext().getTagDeclType(RD),
+                  Out);
+  
+    llvm::GlobalVariable::LinkageTypes linktype;
+    linktype = llvm::GlobalValue::LinkOnceODRLinkage;
+    std::vector<llvm::Constant *> info;
+
+    info.push_back(Buildclass_type_infoDesc());
+    info.push_back(BuildName(RD));
+
+    // FIXME: rest of rtti bits
+
+    llvm::Constant *C;
+    llvm::ArrayType *type = llvm::ArrayType::get(Int8PtrTy, info.size());
+    C = llvm::ConstantArray::get(type, info);
+    llvm::Constant *Rtti = 
+      new llvm::GlobalVariable(CGM.getModule(), type, true, linktype, C,
+                               Out.str());
+    Rtti = llvm::ConstantExpr::getBitCast(Rtti, Int8PtrTy);
+    return Rtti;
+  }
 };
 
 llvm::Constant *CodeGenModule::GenerateRtti(const CXXRecordDecl *RD) {
   RttiBuilder b(*this);
 
-  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(VMContext);
-
-  if (!getContext().getLangOptions().Rtti)
-    return llvm::Constant::getNullValue(Int8PtrTy);
-
-  llvm::SmallString<256> OutName;
-  llvm::raw_svector_ostream Out(OutName);
-  mangleCXXRtti(getMangleContext(), Context.getTagDeclType(RD), Out);
-  
-  llvm::GlobalVariable::LinkageTypes linktype;
-  linktype = llvm::GlobalValue::LinkOnceODRLinkage;
-  std::vector<llvm::Constant *> info;
-  // assert(0 && "FIXME: implement rtti descriptor");
-  // FIXME: descriptor
-  info.push_back(llvm::Constant::getNullValue(Int8PtrTy));
-  info.push_back(b.BuildName(RD));
-
-  // FIXME: rest of rtti bits
-
-  llvm::Constant *C;
-  llvm::ArrayType *type = llvm::ArrayType::get(Int8PtrTy, info.size());
-  C = llvm::ConstantArray::get(type, info);
-  llvm::Constant *Rtti = 
-    new llvm::GlobalVariable(getModule(), type, true, linktype, C,
-                             Out.str());
-  Rtti = llvm::ConstantExpr::getBitCast(Rtti, Int8PtrTy);
-  return Rtti;
+  return  b.Buildclass_type_info(RD);
 }