+;;; Calls FUNCTION with all object that have (possibly conservative)
+;;; references to them on current stack.
+(defun map-stack-references (function)
+ (let ((end
+ (sb!di::descriptor-sap
+ #!+stack-grows-downward-not-upward *control-stack-end*
+ #!-stack-grows-downward-not-upward *control-stack-start*))
+ (sp (current-sp))
+ (seen nil))
+ (loop until #!+stack-grows-downward-not-upward (sap> sp end)
+ #!-stack-grows-downward-not-upward (sap< sp end)
+ do (multiple-value-bind (obj ok) (make-lisp-obj (sap-ref-word sp 0) nil)
+ (when (and ok (typep obj '(not (or fixnum character))))
+ (unless (member obj seen :test #'eq)
+ (funcall function obj)
+ (push obj seen))))
+ (setf sp
+ #!+stack-grows-downward-not-upward (sap+ sp n-word-bytes)
+ #!-stack-grows-downward-not-upward (sap+ sp (- n-word-bytes))))))
+