;;; This is the most general case. In this case, the accessor
;;; generic function has seen more than one class of argument and
;;; more than one slot index. A cache vector stores the wrappers
-;;; and corresponding slot indexes. Because each cache line is
-;;; more than one element long, a cache lock count is used.
+;;; and corresponding slot indexes.
+
(defstruct (dfun-info (:constructor nil)
(:copier nil))
(cache nil))
(t specl2)))
(class-eq (case (car type2)
(eql specl2)
+ ;; FIXME: This says that all CLASS-EQ
+ ;; specializers are equally specific, which
+ ;; is fair enough because only one CLASS-EQ
+ ;; specializer can ever be appliable. If
+ ;; ORDER-SPECIALIZERS should only ever be
+ ;; called on specializers from applicable
+ ;; methods, we could replace this with a BUG.
(class-eq nil)
(class type1)))
(eql (case (car type2)
+ ;; similarly.
(eql nil)
(t specl1))))))))
all-applicable-p
(all-sorted-p t)
function-p)
- (if (null methods)
+ (if (null methods)
(if function-p
(lambda (method-alist wrappers)
(declare (ignore method-alist wrappers))
(return t)))))
\f
(defun update-dfun (generic-function &optional dfun cache info)
- ;; Save DFUN-STATE, so that COMPUTE-DISCRIMINATING-FUNCTION can
- ;; access it, and so that it's there for eg. future cache updates.
- ;;
- ;; How atomic wrt. SET-FUNCALLABLE-INSTANCE-FUN does this need to
- ;; be?
- (set-dfun generic-function dfun cache info)
- (let* ((early-p (early-gf-p generic-function))
- (dfun (if early-p
- (or dfun (make-initial-dfun generic-function))
- (compute-discriminating-function generic-function))))
- (set-funcallable-instance-function generic-function dfun)
- (let ((gf-name (if early-p
- (!early-gf-name generic-function)
- (generic-function-name generic-function))))
- (set-fun-name generic-function gf-name)
- dfun)))
+ (let ((early-p (early-gf-p generic-function)))
+ (flet ((update ()
+ ;; Save DFUN-STATE, so that COMPUTE-DISCRIMINATING-FUNCTION can
+ ;; access it, and so that it's there for eg. future cache updates.
+ (set-dfun generic-function dfun cache info)
+ (let ((dfun (if early-p
+ (or dfun (make-initial-dfun generic-function))
+ (compute-discriminating-function generic-function))))
+ (set-funcallable-instance-function generic-function dfun)
+ (let ((gf-name (if early-p
+ (!early-gf-name generic-function)
+ (generic-function-name generic-function))))
+ (set-fun-name generic-function gf-name)
+ dfun))))
+ ;; This needs to be atomic per generic function, consider:
+ ;; 1. T1 sets dfun-state to S1 and computes discr. fun using S1
+ ;; 2. T2 sets dfun-state to S2 and computes discr. fun using S2
+ ;; 3. T2 sets fin
+ ;; 4. T1 sets fin
+ ;; Oops: now dfun-state and fin don't match! Since just calling
+ ;; a generic can cause the dispatch function to be updated we
+ ;; need a lock here.
+ ;;
+ ;; We need to accept recursion, because PCL is nasty and twisty,
+ ;; and we need to disable interrupts because it would be bad if
+ ;; we updated the DFUN-STATE but not the dispatch function.
+ ;;
+ ;; This is sufficient, because all the other calls to SET-DFUN
+ ;; are part of this same code path (done while the lock is held),
+ ;; which we AVER.
+ ;;
+ ;; FIXME: When our mutexes are smart about the need to wake up
+ ;; sleepers we can put a mutex here instead -- but in the meantime
+ ;; we use a spinlock to avoid a syscall for every dfun update.
+ ;;
+ ;; KLUDGE: No need to lock during bootstrap.
+ (if early-p
+ (update)
+ (let ((lock (gf-lock generic-function)))
+ ;; FIXME: GF-LOCK is a generic function... Are there cases
+ ;; where we can end up in a metacircular loop here? In
+ ;; case there are, better fetch it while interrupts are
+ ;; still enabled...
+ (sb-thread::call-with-recursive-system-spinlock #'update lock))))))
\f
(defvar *dfun-count* nil)
(defvar *dfun-list* nil)
;;; I'm aware of, but they look like they might be useful for
;;; debugging or performance tweaking or something, so I've just
;;; commented them out instead of deleting them. -- WHN 2001-03-28
-#|
(defun list-dfun (gf)
(let* ((sym (type-of (gf-dfun-info gf)))
(a (assq sym *dfun-list*)))
(format t "~% ~S~%" (caddr type+count+sizes)))
*dfun-count*)
(values))
-|#
+||#
(defun gfs-of-type (type)
(unless (consp type) (setq type (list type)))
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