Add new optional getPassName() virtual function that a Pass can override
to make debugging output a lot nicer.

llvm-svn: 2395
diff --git a/llvm/lib/Transforms/IPO/SimpleStructMutation.cpp b/llvm/lib/Transforms/IPO/SimpleStructMutation.cpp
index 33e0289..c0d9ef4 100644
--- a/llvm/lib/Transforms/IPO/SimpleStructMutation.cpp
+++ b/llvm/lib/Transforms/IPO/SimpleStructMutation.cpp
@@ -18,12 +18,13 @@
 using std::pair;
 
 namespace {
-  class SimpleStructMutation : public MutateStructTypes {
-  public:
+  struct SimpleStructMutation : public MutateStructTypes {
     enum Transform { SwapElements, SortElements } CurrentXForm;
     
     SimpleStructMutation(enum Transform XForm) : CurrentXForm(XForm) {}
     
+    const char *getPassName() const { return "Simple Struct Mutation"; }
+    
     virtual bool run(Module *M) {
       setTransforms(getTransforms(M, CurrentXForm));
       bool Changed = MutateStructTypes::run(M);