diff -r e04c5be84792 -r dd57743d220e jitcraft/Types.cpp
--- a/jitcraft/Types.cpp	Sun Jul 08 15:23:48 2012 -0700
+++ b/jitcraft/Types.cpp	Sun Jul 08 16:49:17 2012 -0700
@@ -109,3 +109,44 @@
     type->parameters_ = parameters;
     return type;
 }
+
+bool
+Type::Compare(Type *left, Type *right)
+{
+    if (left->kind() != right->kind())
+        return false;
+
+    switch (left->kind()) {
+      case Type::PRIMITIVE:
+        return (left->primitive() == right->primitive() &&
+                left->tag() == right->tag());
+
+      case Type::ARRAY:
+      {
+        if (left->levels() != right->levels())
+          return false;
+        if (left->elements() != right->elements())
+          return false;
+        return Compare(left->contained(), right->contained());
+      }
+
+      case Type::FUNCTION:
+      {
+        if (!Compare(left->returnType(), right->returnType()))
+            return false;
+        if (left->parameters()->length() != right->parameters()->length())
+            return false;
+        for (unsigned i = 0; i < left->parameters()->length(); i++) {
+            Type *leftparam = left->parameterAt(i);
+            Type *rightparam = right->parameterAt(i);
+            if (!Compare(leftparam, rightparam))
+                return false;
+        }
+        return true;
+      }
+
+      default:
+        assert(left->kind() == Type::REFERENCE);
+        return Compare(left->contained(), right->contained());
+    }
+}