system will be deadlocked. Since SBCL does not currently document its internal
locks, application code can never be certain that this invariant is
maintained."
- `(unwind-protect
- (let* ((*interrupts-enabled* nil)
- (*gc-inhibit* t))
- ,@body)
- (when (or (and *interrupts-enabled* *interrupt-pending*)
- (and (not *gc-inhibit*)
- (or *gc-pending* #!+sb-thread *stop-for-gc-pending*)))
- (sb!unix::receive-pending-interrupt))))
-
+ (with-unique-names (without-gcing-body)
+ `(flet ((,without-gcing-body ()
+ ,@body))
+ (if *gc-inhibit*
+ (,without-gcing-body)
+ (without-interrupts
+ ;; We need to disable interrupts before disabling GC, so that
+ ;; signal handlers using locks don't accidentally try to grab
+ ;; them with GC inhibited.
+ ;;
+ ;; It would be nice to implement this with just a single UWP, but
+ ;; unfortunately it seems that it cannot be done: the naive
+ ;; solution of binding both *INTERRUPTS-ENABLED* and
+ ;; *GC-INHIBIT*, and checking for both pending GC and interrupts
+ ;; in the cleanup breaks if we have a GC pending, but no
+ ;; interrupts, and we receive an asynch unwind while checking for
+ ;; the pending GC: we unwind before handling the pending GC, and
+ ;; will be left running with further GCs blocked due to the GC
+ ;; pending flag.
+ (unwind-protect
+ (let ((*gc-inhibit* t))
+ (,without-gcing-body))
+ (when (or *gc-pending* #!+sb-thread *stop-for-gc-pending*)
+ (sb!unix::receive-pending-interrupt))))))))
\f
;;; EOF-OR-LOSE is a useful macro that handles EOF.
(defmacro eof-or-lose (stream eof-error-p eof-value)
;;; within the scope of a PREPARE-FOR-FAST-READ-CHAR.
(defmacro fast-read-char (&optional (eof-error-p t) (eof-value ()))
`(cond
- ((not %frc-buffer%)
- (funcall %frc-method% %frc-stream% ,eof-error-p ,eof-value))
- ((= %frc-index% +ansi-stream-in-buffer-length+)
- (prog1 (fast-read-char-refill %frc-stream% ,eof-error-p ,eof-value)
- (setq %frc-index% (ansi-stream-in-index %frc-stream%))))
- (t
- (prog1 (aref %frc-buffer% %frc-index%)
- (incf %frc-index%)))))
+ ((not %frc-buffer%)
+ (funcall %frc-method% %frc-stream% ,eof-error-p ,eof-value))
+ ((= %frc-index% +ansi-stream-in-buffer-length+)
+ (multiple-value-bind (eof-p index-or-value)
+ (fast-read-char-refill %frc-stream% ,eof-error-p ,eof-value)
+ (if eof-p
+ index-or-value
+ (progn
+ (setq %frc-index% (1+ index-or-value))
+ (aref %frc-buffer% index-or-value)))))
+ (t
+ (prog1 (aref %frc-buffer% %frc-index%)
+ (incf %frc-index%)))))
;;;; And these for the fasloader...