1.0.17.21: LIST-FILL* return value (regression 1.0.12.16)

[sbcl.git] / src / code / sysmacs.lisp

diff --git a/src/code/sysmacs.lisp b/src/code/sysmacs.lisp
index 3556bc1..60f18d7 100644 (file)
--- a/src/code/sysmacs.lisp
+++ b/src/code/sysmacs.lisp
@@ -48,13 +48,30 @@ stopped for GC while T2 is waiting for the lock inside WITHOUT-GCING the
 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
-        (without-interrupts
-          (let ((*gc-inhibit* t))
-            ,@body))
-     ;; the test is racy, but it can err only on the overeager side
-     (sb!kernel::maybe-handle-pending-gc)))
-
+  (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)
@@ -149,14 +166,19 @@ maintained."
 ;;; 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...