+;;;; support for threads needed at cross-compile time
+
+;;;; This software is part of the SBCL system. See the README file for
+;;;; more information.
+;;;;
+;;;; This software is derived from the CMU CL system, which was
+;;;; written at Carnegie Mellon University and released into the
+;;;; public domain. The software is in the public domain and is
+;;;; provided with absolutely no warranty. See the COPYING and CREDITS
+;;;; files for more information.
+
(in-package "SB!THREAD")
+(sb!xc:defmacro with-mutex ((mutex &key value (wait-p t)) &body body)
+ #!+sb-doc
+ "Acquire MUTEX for the dynamic scope of BODY, setting it to
+NEW-VALUE or some suitable default value if NIL. If WAIT-P is non-NIL
+and the mutex is in use, sleep until it is available"
+ #!-sb-thread (declare (ignore mutex value wait-p))
+ #!+sb-thread
+ (with-unique-names (got)
+ `(let ((,got (get-mutex ,mutex ,value ,wait-p)))
+ (when ,got
+ (unwind-protect
+ (locally ,@body)
+ (release-mutex ,mutex)))))
+ ;; KLUDGE: this separate expansion for (NOT SB-THREAD) is not
+ ;; strictly necessary; GET-MUTEX and RELEASE-MUTEX are implemented.
+ ;; However, there would be a (possibly slight) performance hit in
+ ;; using them.
+ #!-sb-thread
+ `(locally ,@body))
+
(sb!xc:defmacro with-recursive-lock ((mutex) &body body)
+ #!+sb-doc
+ "Acquires MUTEX for the dynamic scope of BODY. Within that scope
+further recursive lock attempts for the same mutex succeed. However,
+it is an error to mix WITH-MUTEX and WITH-RECURSIVE-LOCK for the same
+mutex."
+ #!-sb-thread (declare (ignore mutex))
#!+sb-thread
- (with-unique-names (cfp)
- `(let ((,cfp (sb!kernel:current-fp)))
- (unless (and (mutex-value ,mutex)
- (sb!vm:control-stack-pointer-valid-p
- (sb!sys:int-sap
- (sb!kernel:get-lisp-obj-address (mutex-value ,mutex)))))
+ (with-unique-names (cfp inner-lock)
+ `(let ((,cfp (sb!kernel:current-fp))
+ (,inner-lock
+ (and (mutex-value ,mutex)
+ (sb!vm:control-stack-pointer-valid-p
+ (sb!sys:int-sap
+ (sb!kernel:get-lisp-obj-address (mutex-value ,mutex)))))))
+ (unless ,inner-lock
;; this punning with MAKE-LISP-OBJ depends for its safety on
;; the frame pointer being a lispobj-aligned integer. While
;; it is, then MAKE-LISP-OBJ will always return a FIXNUM, so
;; confuse GC completely. -- CSR, 2003-06-03
(get-mutex ,mutex (sb!kernel:make-lisp-obj (sb!sys:sap-int ,cfp))))
(unwind-protect
- (progn ,@body)
- (when (sb!sys:sap= (sb!sys:int-sap
- (sb!kernel:get-lisp-obj-address
- (mutex-value ,mutex)))
- ,cfp)
+ (locally ,@body)
+ (unless ,inner-lock
(release-mutex ,mutex)))))
#!-sb-thread
- `(progn ,@body))
-
+ `(locally ,@body))