slime.diff

diff --git a/swank/sbcl.lisp b/swank/sbcl.lisp
index a09e04b3..78038659 100644
--- a/swank/sbcl.lisp
+++ b/swank/sbcl.lisp
@@ -979,7 +979,8 @@ QUALITIES is an alist with (quality . value)"
        (make-location `(:file ,(namestring
                                 (translate-logical-pathname pathname)))
                       '(:position 1)
-                      (when (eql type :function)
+                      (when (and (eql type :function)
+                                 (symbolp name))
                         `(:snippet ,(format nil "(defun ~a "
                                             (symbol-name name))))))
       (:invalid
@@ -1666,7 +1667,7 @@ stack."
     (sb-thread:with-mutex (*thread-id-counter-lock*)
       (incf *thread-id-counter*)))
 
-  (defparameter *thread-id-map* (make-hash-table))
+  (defvar *thread-id-map* (make-hash-table))
 
   ;; This should be a thread -> id map but as weak keys are not
   ;; supported it is id -> map instead.
@@ -1741,10 +1742,33 @@ stack."
   (defvar *mailboxes* (list))
   (declaim (type list *mailboxes*))
 
+  (defun make-sem ()
+    (declare (optimize speed))
+    (sb-alien:alien-funcall
+     (sb-alien:extern-alien
+      "dispatch_semaphore_create"
+      (function sb-sys:system-area-pointer sb-alien:long))
+                            0))
+
+  (defun wait-sem (sem)
+    (declare (optimize speed))
+    (sb-alien:alien-funcall
+     (sb-alien:extern-alien "dispatch_semaphore_wait"
+                            (function sb-alien:long sb-sys:system-area-pointer sb-alien:long-long))
+     sem
+     -1))
+
+  (defun signal-sem (sem)
+    (declare (optimize speed))
+    (sb-alien:alien-funcall
+     (sb-alien:extern-alien "dispatch_semaphore_signal"
+                            (function sb-alien:long sb-sys:system-area-pointer))
+     sem))
+
   (defstruct (mailbox (:conc-name mailbox.))
     thread
     (mutex (sb-thread:make-mutex))
-    (waitqueue  (sb-thread:make-waitqueue))
+    (sem  (make-sem))
     (queue '() :type list))
 
   (defun mailbox (thread)
@@ -1756,23 +1780,21 @@ stack."
             mb))))
 
   (defimplementation wake-thread (thread)
-    (let* ((mbox (mailbox thread))
-           (mutex (mailbox.mutex mbox)))
-      (sb-thread:with-recursive-lock (mutex)
-        (sb-thread:condition-broadcast (mailbox.waitqueue mbox)))))
+    (signal-sem (mailbox.sem (mailbox thread))))
+
 
   (defimplementation send (thread message)
     (let* ((mbox (mailbox thread))
            (mutex (mailbox.mutex mbox)))
       (sb-thread:with-mutex (mutex)
         (setf (mailbox.queue mbox)
-              (nconc (mailbox.queue mbox) (list message)))
-        (sb-thread:condition-broadcast (mailbox.waitqueue mbox)))))
-
+              (nconc (mailbox.queue mbox) (list message))))
+      (signal-sem (mailbox.sem mbox))))
+  
   (defimplementation receive-if (test &optional timeout)
     (let* ((mbox (mailbox (current-thread)))
            (mutex (mailbox.mutex mbox))
-           (waitq (mailbox.waitqueue mbox)))
+           (sem (mailbox.sem mbox)))
       (assert (or (not timeout) (eq timeout t)))
       (loop
        (check-slime-interrupts)
@@ -1781,9 +1803,9 @@ stack."
                 (tail (member-if test q)))
            (when tail
              (setf (mailbox.queue mbox) (nconc (ldiff q tail) (cdr tail)))
-             (return (car tail))))
-         (when (eq timeout t) (return (values nil t)))
-         (sb-thread:condition-wait waitq mutex)))))
+             (return (car tail)))))
+       (when (eq timeout t) (return (values nil t)))
+       (wait-sem sem))))
 
   (let ((alist '())
         (mutex (sb-thread:make-mutex :name "register-thread")))

Thanks, @stassats!