diff --git a/vm/builtin/data.cpp b/vm/builtin/data.cpp
index 567ca0d265..94aea31dc8 100644
--- a/vm/builtin/data.cpp
+++ b/vm/builtin/data.cpp
@@ -29,9 +29,9 @@ namespace rubinius {
     return data;
   }
 
-  void Data::finalize(STATE) {
-    FreeFunctor f = this->free();
-    if(f) f(data());
+  void Data::finalize(STATE, Data* data) {
+    FreeFunctor f = data->free();
+    if(f) f(data->data());
   }
 
   void Data::Info::mark(Object* t, ObjectMark& mark) {
diff --git a/vm/builtin/data.hpp b/vm/builtin/data.hpp
index 145a5e6039..3d48986c18 100644
--- a/vm/builtin/data.hpp
+++ b/vm/builtin/data.hpp
@@ -35,7 +35,7 @@ namespace rubinius {
     /** New Data instance. */
     static Data*  create(STATE, void* data, MarkFunctor mark, FreeFunctor free);
 
-    void finalize(STATE);
+    static void finalize(STATE, Data* data);
 
     RDataExposed* exposed() {
       return &exposed_;
diff --git a/vm/builtin/dir.cpp b/vm/builtin/dir.cpp
index 32a3ae55bb..9166b6c98a 100644
--- a/vm/builtin/dir.cpp
+++ b/vm/builtin/dir.cpp
@@ -24,7 +24,7 @@ namespace rubinius {
     Dir* d = state->new_object<Dir>(G(dir));
     d->os_ = 0;
 
-    state->om->needs_finalization(d);
+    state->om->needs_finalization(d, (FinalizerFunction)&Dir::finalize);
 
     return d;
   }
@@ -39,10 +39,10 @@ namespace rubinius {
     return dir;
   }
 
-  void Dir::finalize(STATE) {
-    if(os_) {
-      closedir(os_);
-      os_ = 0;
+  void Dir::finalize(STATE, Dir* dir) {
+    if(dir->os_) {
+      closedir(dir->os_);
+      dir->os_ = 0;
     }
   }
 
diff --git a/vm/builtin/dir.hpp b/vm/builtin/dir.hpp
index 20061b4a01..fbecc42c08 100644
--- a/vm/builtin/dir.hpp
+++ b/vm/builtin/dir.hpp
@@ -29,7 +29,7 @@ namespace rubinius {
 
     static Dir* create(STATE);
 
-    void finalize(STATE);
+    static void finalize(STATE, Dir* dir);
 
     // Ruby.primitive :dir_allocate
     static Dir* allocate(STATE, Object* self);
diff --git a/vm/builtin/fiber.cpp b/vm/builtin/fiber.cpp
index 4f7ebd6176..9a456a0c4a 100644
--- a/vm/builtin/fiber.cpp
+++ b/vm/builtin/fiber.cpp
@@ -37,7 +37,7 @@ namespace rubinius {
       fib->stack_ = state->stack_start();
       fib->context_ = new ucontext_t;
 
-      state->om->needs_finalization(fib);
+      state->om->needs_finalization(fib, (FinalizerFunction)&Fiber::finalize);
 
       state->current_fiber.set(fib);
     }
@@ -98,7 +98,7 @@ namespace rubinius {
     fib->stack_ = malloc(stack_size);
     fib->context_ = new ucontext_t;
 
-    state->om->needs_finalization(fib);
+    state->om->needs_finalization(fib, (FinalizerFunction)&Fiber::finalize);
 
     ucontext_t* ctx = fib->ucontext();
 
@@ -189,10 +189,10 @@ namespace rubinius {
 #endif
   }
 
-  void Fiber::finalize(STATE) {
+  void Fiber::finalize(STATE, Fiber* fib) {
 #ifdef FIBER_ENABLED
-    delete context_;
-    if(stack_ && !root_) free(stack_);
+    delete fib->context_;
+    if(fib->stack_ && !fib->root_) free(fib->stack_);
 #endif
   }
 
diff --git a/vm/builtin/fiber.hpp b/vm/builtin/fiber.hpp
index c19b08fa85..94c8c171d8 100644
--- a/vm/builtin/fiber.hpp
+++ b/vm/builtin/fiber.hpp
@@ -92,7 +92,7 @@ namespace rubinius {
     // Ruby.primitive :fiber_s_yield
     static Object* s_yield(STATE, Arguments& args, CallFrame* calling_environment);
 
-    void finalize(STATE);
+    static void finalize(STATE, Fiber* fib);
 
   public:   /* TypeInfo */
 
diff --git a/vm/builtin/io.cpp b/vm/builtin/io.cpp
index 52344c7580..0e163d45c6 100644
--- a/vm/builtin/io.cpp
+++ b/vm/builtin/io.cpp
@@ -43,7 +43,7 @@ namespace rubinius {
 
     // Don't bother to add finalization for stdio
     if(fd >= 3) {
-      state->om->needs_finalization(io);
+      state->om->needs_finalization(io, (FinalizerFunction)&IO::finalize);
     }
 
     return io;
@@ -60,7 +60,7 @@ namespace rubinius {
     // Ensure the instance's class is set (i.e. for subclasses of IO)
     io->klass(state, as<Class>(self));
 
-    state->om->needs_finalization(io);
+    state->om->needs_finalization(io, (FinalizerFunction)&IO::finalize);
 
     return io;
   }
@@ -385,15 +385,15 @@ namespace rubinius {
     mode(state, Fixnum::from((m & ~O_ACCMODE) | O_WRONLY));
   }
 
-  void IO::finalize(STATE) {
-    if(descriptor_->nil_p()) return;
+  void IO::finalize(STATE, IO* io) {
+    if(io->descriptor()->nil_p()) return;
 
-    native_int fd = descriptor_->to_native();
+    native_int fd = io->descriptor()->to_native();
 
     // don't close stdin, stdout, stderr (0, 1, 2)
     if(fd >= 3) {
       ::close(fd);
-      descriptor(state, Fixnum::from(-1));
+      io->descriptor(state, Fixnum::from(-1));
     }
   }
 
diff --git a/vm/builtin/io.hpp b/vm/builtin/io.hpp
index 368240d243..c00a7cc571 100644
--- a/vm/builtin/io.hpp
+++ b/vm/builtin/io.hpp
@@ -43,7 +43,7 @@ namespace rubinius {
     void unsafe_set_descriptor(native_int fd);
     void force_read_only(STATE);
     void force_write_only(STATE);
-    void finalize(STATE);
+    static void finalize(STATE, IO* io);
 
   /* Class primitives */
 
diff --git a/vm/builtin/memorypointer.cpp b/vm/builtin/memorypointer.cpp
index 4f96335c79..b3a0325a4e 100644
--- a/vm/builtin/memorypointer.cpp
+++ b/vm/builtin/memorypointer.cpp
@@ -58,16 +58,17 @@ namespace rubinius {
     autorelease = val->true_p() ? true : false;
 
     if(autorelease && !set_finalizer) {
-      state->om->needs_finalization(this);
+      state->om->needs_finalization(this,
+          (FinalizerFunction)&MemoryPointer::finalize);
       set_finalizer = true;
     }
 
     return val;
   }
 
-  void MemoryPointer::finalize(STATE) {
-    if(autorelease && pointer) {
-      ::free(pointer);
+  void MemoryPointer::finalize(STATE, MemoryPointer* ptr) {
+    if(ptr->autorelease && ptr->pointer) {
+      ::free(ptr->pointer);
     }
   }
 
diff --git a/vm/builtin/memorypointer.hpp b/vm/builtin/memorypointer.hpp
index 077b3b9754..8c8da039d6 100644
--- a/vm/builtin/memorypointer.hpp
+++ b/vm/builtin/memorypointer.hpp
@@ -17,7 +17,7 @@ namespace rubinius {
 
     static MemoryPointer* create(STATE, void* ptr);
 
-    void finalize(STATE);
+    static void finalize(STATE, MemoryPointer* ptr);
 
     // Ruby.primitive :memorypointer_address
     Integer* get_address(STATE);
diff --git a/vm/gc/finalize.hpp b/vm/gc/finalize.hpp
index 33b1bcdead..9185eed2ba 100644
--- a/vm/gc/finalize.hpp
+++ b/vm/gc/finalize.hpp
@@ -1,5 +1,7 @@
 namespace rubinius {
 
+  typedef void (*FinalizerFunction)(STATE, Object*);
+
   struct FinalizeObject {
   public:
     enum FinalizationStatus {
@@ -11,11 +13,13 @@ namespace rubinius {
   public:
     FinalizeObject()
       : queue_count(0)
+      , finalizer(0)
     {}
 
     Object* object;
     FinalizationStatus status;
     int queue_count;
+    FinalizerFunction finalizer;
 
     void queued() {
       status = eQueued;
diff --git a/vm/objectmemory.cpp b/vm/objectmemory.cpp
index 9abcf2b43d..6d3a064c21 100644
--- a/vm/objectmemory.cpp
+++ b/vm/objectmemory.cpp
@@ -452,10 +452,11 @@ namespace rubinius {
     code_manager_.add_resource(cr);
   }
 
-  void ObjectMemory::needs_finalization(Object* obj) {
+  void ObjectMemory::needs_finalization(Object* obj, FinalizerFunction func) {
     FinalizeObject fi;
     fi.object = obj;
     fi.status = FinalizeObject::eLive;
+    fi.finalizer = func;
 
     // Makes a copy of fi.
     finalize_.push_back(fi);
@@ -466,16 +467,8 @@ namespace rubinius {
         i != to_finalize_.end(); ) {
       FinalizeObject* fi = *i;
 
-      if(IO* io = try_as<IO>(fi->object)) {
-        io->finalize(state);
-      } else if(Fiber* fib = try_as<Fiber>(fi->object)) {
-        fib->finalize(state);
-      } else if(MemoryPointer* ptr = try_as<MemoryPointer>(fi->object)) {
-        ptr->finalize(state);
-      } else if(Data* data = try_as<Data>(fi->object)) {
-        data->finalize(state);
-      } else if(Dir* dir = try_as<Dir>(fi->object)) {
-        dir->finalize(state);
+      if(fi->finalizer) {
+        (*fi->finalizer)(state, fi->object);
       } else {
         std::cerr << "Unsupported object to be finalized: "
                   << fi->object->to_s(state)->c_str() << "\n";
diff --git a/vm/objectmemory.hpp b/vm/objectmemory.hpp
index e46f84b2b9..1cb9d843bb 100644
--- a/vm/objectmemory.hpp
+++ b/vm/objectmemory.hpp
@@ -193,7 +193,7 @@ namespace rubinius {
 
     int mature_bytes_allocated();
 
-    void needs_finalization(Object* obj);
+    void needs_finalization(Object* obj, FinalizerFunction func = 0);
     void run_finalizers(STATE);
 
     void find_referers(Object* obj, ObjectArray& result);