fix printing call graphs


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27820 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/tools/opt/AnalysisWrappers.cpp b/tools/opt/AnalysisWrappers.cpp
index 8e5c333..b371d50 100644
--- a/tools/opt/AnalysisWrappers.cpp
+++ b/tools/opt/AnalysisWrappers.cpp
@@ -71,7 +71,7 @@
     }
     virtual bool runOnModule(Module &M) { return false; }
 
-    void print(std::ostream &OS, Module *M) const {
+    virtual void print(std::ostream &OS, const Module *M) const {
       getAnalysis<CallGraph>().print(OS, M);
     }
   };