--- a/src/pt-stmt.h	Tue Mar 04 15:07:44 2008 -0500
+++ b/src/pt-stmt.h	Tue Mar 04 17:01:05 2008 -0500
@@ -31,6 +31,8 @@
 
 class tree_walker;
 
+#include <deque>
+
 #include "base-list.h"
 #include "comment-list.h"
 #include "symtab.h"
@@ -158,11 +160,105 @@
   tree_statement_list& operator = (const tree_statement_list&);
 };
 
-// Pointer to the current statement being executed.
-extern tree_statement *curr_statement;
+class tree_statement_stack
+{
+protected:
+
+  tree_statement_stack (void) : tss () { }
+
+public:
+
+  typedef std::deque<tree_statement *>::iterator iterator ;
+
+  static bool instance_ok (void)
+  {
+    bool retval = true;
+
+    if (! instance)
+      instance = new tree_statement_stack ();
+
+    if (! instance)
+      {
+	::error ("unable to create stmt stack object!");
+
+	retval = false;
+      }
+
+    return retval;
+  }
+
+  // Current statement (top of stack).
+  static tree_statement *current (void) { return top (); }
+
+  static int current_line (void)
+  {
+    tree_statement *s = current ();
+    return s ? s->line () : -1;
+  }
+
+  static int current_column (void)
+  {
+    tree_statement *s = current ();
+    return s ? s->column () : -1;
+  }
+
+  // Statement at position N on the call stack (N == 0 is current).
+  static tree_statement *element (size_t n)
+  {
+    return instance_ok () ? instance->do_element (n) : 0;
+  }
 
-// Pointer to the current statement being executed in the calling function.
-extern tree_statement *curr_caller_statement;
+  // Caller statement
+  static tree_statement *caller (void) { return element (1); }
+
+  static void push (tree_statement *f)
+  {
+    if (instance_ok ())
+      instance->do_push (f);
+  }
+
+  static tree_statement *top (void)
+  {
+    return instance_ok () ? instance->do_top (): 0;
+  }
+
+  static void pop (void)
+  {
+    if (instance_ok ())
+      instance->do_pop ();
+  }
+  
+  // A function for popping the top of the call stack that is suitable
+  // for use as an unwind_protect handler.
+  static void unwind_pop (void *) { pop (); }
+
+  static void clear (void)
+  {
+    if (instance_ok ())
+      instance->do_clear ();
+  }
+
+private:
+
+  // The current stmt stack.
+  std::deque<tree_statement *> tss;
+
+  static tree_statement_stack *instance;
+
+  tree_statement *do_element (size_t n) { return tss.size () > n ? tss[n] : 0; }
+
+  void do_push (tree_statement *f) { tss.push_front (f); }
+
+  tree_statement *do_top (void) { return tss.empty () ? 0 : tss.front (); }
+
+  void do_pop (void)
+  {
+    if (! tss.empty ())
+      tss.pop_front ();
+  }
+
+  void do_clear (void) { tss.clear (); }
+};
 
 #endif