diff -r a350c2cc736a -r 75e385f68b7e jitcraft/Stack.h
--- a/jitcraft/Stack.h	Fri Jun 29 19:35:17 2012 -0700
+++ b/jitcraft/Stack.h	Sat Jun 30 19:38:53 2012 -0700
@@ -21,16 +21,19 @@
 #include <stddef.h>
 #include "Utility.h"
 #include "Code.h"
-#include "UnsafeArray.h"
 
 namespace jc {
+
+class Object;
+class Array;
     
 union LocalSlot
 {
     int i32;
     float f;
-    void *p;
-    UnsafeArray *unsafeArray;
+    Address address;
+    Object *obj;
+    Array *array;
 };
 
 struct Top
@@ -56,14 +59,14 @@
     Frame *prev_;
     bytecode *prevpc_;
     Code *code_;
-    void *prevUnsafeStack_;
+    Address lifoPosition_;
 
   public:
-    Frame(Frame *prev, bytecode *prevpc, Code *code, void *prevUnsafeStack)
+    Frame(Frame *prev, bytecode *prevpc, Code *code, Address lifoPosition)
       : prev_(prev),
         prevpc_(prevpc),
         code_(code),
-        prevUnsafeStack_(prevUnsafeStack)
+        lifoPosition_(lifoPosition)
     {
     }
 
@@ -82,8 +85,8 @@
     bytecode *prevpc() const {
         return prevpc_;
     }
-    void *prevUnsafeStack() const {
-        return prevUnsafeStack_;
+    Address lifoPosition() const {
+        return lifoPosition_;
     }
     LocalSlot &arg(unsigned slot) {
         assert(slot < code()->nargs());
@@ -121,51 +124,6 @@
     }
 };
 
-// The unsafe stack is designed for structures which interop unsafely with C++.
-// In this stack, buffers can be overrun, even inside the VM - but with two
-// caveats:
-//
-//  The unsafe stack cannot hold safe references.
-//  Indirect reads and writes from the unsafe stack cannot escape the unsafe
-//  stack.
-class UnsafeStack
-{
-    char *buffer_;
-    char *pos_;
-    char *end_;
-
-  private:
-    static const size_t STACK_SIZE = 1024 * 1024;
-
-  public:
-    UnsafeStack();
-    ~UnsafeStack();
-    bool initialize();
-
-  public:
-    void *position() const {
-        return pos_;
-    }
-    void *allocate(size_t nbytes) {
-        nbytes = Align(nbytes, kMallocAlignment);
-
-        if (pos_ + nbytes > end_) {
-            assert(false);
-            return NULL;
-        }
-
-        void *ptr = pos_;
-        pos_ += nbytes;
-        return ptr;
-    }
-
-    void unwind(void *to) {
-        char *p = (char *)to;
-        assert(p < pos_ && p >= buffer_);
-        pos_ = p;
-    }
-};
-
 }
 
 #endif // _include_jc_stack_h_