(in-package "SB!THREAD")
+;;; Conditions
+
+(define-condition thread-error (error)
+ ((thread :reader thread-error-thread :initarg :thread))
+ #!+sb-doc
+ (:documentation
+ "Conditions of type THREAD-ERROR are signalled when thread operations fail.
+The offending thread is initialized by the :THREAD initialization argument and
+read by the function THREAD-ERROR-THREAD."))
+
+#!+sb-doc
+(setf
+ (fdocumentation 'thread-error-thread 'function)
+ "Return the offending thread that the THREAD-ERROR pertains to.")
+
+(define-condition symbol-value-in-thread-error (cell-error thread-error)
+ ((info :reader symbol-value-in-thread-error-info :initarg :info))
+ (:report
+ (lambda (condition stream)
+ (destructuring-bind (op problem)
+ (symbol-value-in-thread-error-info condition)
+ (format stream "Cannot ~(~A~) value of ~S in ~S: ~S"
+ op
+ (cell-error-name condition)
+ (thread-error-thread condition)
+ (ecase problem
+ (:unbound-in-thread "the symbol is unbound in thread.")
+ (:no-tls-value "the symbol has no thread-local value.")
+ (:thread-dead "the thread has exited.")
+ (:invalid-tls-value "the thread-local value is not valid."))))))
+ #!+sb-doc
+ (:documentation
+ "Signalled when SYMBOL-VALUE-IN-THREAD or its SETF version fails due to eg.
+the symbol not having a thread-local value, or the target thread having
+exited. The offending symbol can be accessed using CELL-ERROR-NAME, and the
+offending thread using THREAD-ERROR-THREAD."))
+
+(define-condition join-thread-error (thread-error) ()
+ (:report (lambda (c s)
+ (format s "Joining thread failed: thread ~A ~
+ did not return normally."
+ (thread-error-thread c))))
+ #!+sb-doc
+ (:documentation
+ "Signalled when joining a thread fails due to abnormal exit of the thread
+to be joined. The offending thread can be accessed using
+THREAD-ERROR-THREAD."))
+
+(defun join-thread-error-thread (condition)
+ (thread-error-thread condition))
+(define-compiler-macro join-thread-error-thread (condition)
+ (deprecation-warning 'join-thread-error-thread 'thread-error-thread)
+ `(thread-error-thread ,condition))
+
+#!+sb-doc
+(setf
+ (fdocumentation 'join-thread-error-thread 'function)
+ "The thread that we failed to join. Deprecated, use THREAD-ERROR-THREAD
+instead.")
+
+(define-condition interrupt-thread-error (thread-error) ()
+ (:report (lambda (c s)
+ (format s "Interrupt thread failed: thread ~A has exited."
+ (thread-error-thread c))))
+ #!+sb-doc
+ (:documentation
+ "Signalled when interrupting a thread fails because the thread has already
+exited. The offending thread can be accessed using THREAD-ERROR-THREAD."))
+
+(defun interrupt-thread-error-thread (condition)
+ (thread-error-thread condition))
+(define-compiler-macro interrupt-thread-error-thread (condition)
+ (deprecation-warning 'join-thread-error-thread 'thread-error-thread)
+ `(thread-error-thread ,condition))
+
+#!+sb-doc
+(setf
+ (fdocumentation 'interrupt-thread-error-thread 'function)
+ "The thread that was not interrupted. Deprecated, use THREAD-ERROR-THREAD
+instead.")
+
;;; Of the WITH-PINNED-OBJECTS in this file, not every single one is
;;; necessary because threads are only supported with the conservative
;;; gencgc and numbers on the stack (returned by GET-LISP-OBJ-ADDRESS)
(setf (fdocumentation '*current-thread* 'variable)
"Bound in each thread to the thread itself.")
-(defstruct (thread (:constructor %make-thread))
- #!+sb-doc
- "Thread type. Do not rely on threads being structs as it may change
-in future versions."
- name
- %alive-p
- os-thread
- interruptions
- (interruptions-lock (make-mutex :name "thread interruptions lock"))
- result
- (result-lock (make-mutex :name "thread result lock")))
-
#!+sb-doc
-(setf (fdocumentation 'thread-name 'function)
- "The name of the thread. Setfable.")
+(setf
+ (fdocumentation 'thread-name 'function)
+ "Name of the thread. Can be assigned to using SETF. Thread names can be
+arbitrary printable objects, and need not be unique.")
(def!method print-object ((thread thread) stream)
(print-unreadable-object (thread stream :type t :identity t)
(defun thread-alive-p (thread)
#!+sb-doc
- "Check if THREAD is running."
+ "Return T if THREAD is still alive. Note that the return value is
+potentially stale even before the function returns, as the thread may exit at
+any time."
(thread-%alive-p thread))
;; A thread is eligible for gc iff it has finished and there are no
(defun list-all-threads ()
#!+sb-doc
- "Return a list of the live threads."
+ "Return a list of the live threads. Note that the return value is
+potentially stale even before the function returns, as new threads may be
+created and old ones may exit at any time."
(with-all-threads-lock
(copy-list *all-threads*)))
(define-alien-routine ("create_thread" %create-thread)
unsigned-long (lisp-fun-address unsigned-long))
- (define-alien-routine "block_deferrable_signals"
- void)
+ (declaim (inline %block-deferrable-signals))
+ (define-alien-routine ("block_deferrable_signals" %block-deferrable-signals)
+ void
+ (where sb!alien:unsigned-long)
+ (old sb!alien:unsigned-long))
+
+ (defun block-deferrable-signals ()
+ (%block-deferrable-signals 0 0))
#!+sb-lutex
(progn
(allow-with-interrupts
(futex-wait (waitqueue-data-address queue)
(get-lisp-obj-address me)
- ;; our way if saying "no
+ ;; our way of saying "no
;; timeout":
(or to-sec -1)
(or to-usec 0))))
;; them before entering the debugger, but this is
;; better than nothing.
(allow-with-interrupts (get-mutex mutex)))
- ;; ETIMEDOUT
- ((1) (signal-deadline))
+ ;; ETIMEDOUT; we know it was a timeout, yet we cannot
+ ;; signal a deadline unconditionally here because the
+ ;; call to GET-MUTEX may already have signaled it.
+ ((1))
;; EINTR
((2))
;; EWOULDBLOCK, -1 here, is the possible spurious wakeup
(wait-on-semaphore setup-sem)
thread)))))
-(define-condition join-thread-error (error)
- ((thread :reader join-thread-error-thread :initarg :thread))
- #!+sb-doc
- (:documentation "Joining thread failed.")
- (:report (lambda (c s)
- (format s "Joining thread failed: thread ~A ~
- has not returned normally."
- (join-thread-error-thread c)))))
-
-#!+sb-doc
-(setf (fdocumentation 'join-thread-error-thread 'function)
- "The thread that we failed to join.")
-
(defun join-thread (thread &key (default nil defaultp))
#!+sb-doc
"Suspend current thread until THREAD exits. Returns the result
"Deprecated. Same as TERMINATE-THREAD."
(terminate-thread thread))
-(define-condition interrupt-thread-error (error)
- ((thread :reader interrupt-thread-error-thread :initarg :thread))
- #!+sb-doc
- (:documentation "Interrupting thread failed.")
- (:report (lambda (c s)
- (format s "Interrupt thread failed: thread ~A has exited."
- (interrupt-thread-error-thread c)))))
-
-#!+sb-doc
-(setf (fdocumentation 'interrupt-thread-error-thread 'function)
- "The thread that was not interrupted.")
-
(defmacro with-interruptions-lock ((thread) &body body)
`(with-system-mutex ((thread-interruptions-lock ,thread))
,@body))
sb!vm::thread-next-slot)))))))
(defun %symbol-value-in-thread (symbol thread)
- (tagbody
- ;; Prevent the dead from dying completely while we look for the
- ;; TLS area...
- (with-all-threads-lock
- (if (thread-alive-p thread)
- (let* ((offset (* sb!vm:n-word-bytes
- (sb!vm::symbol-tls-index symbol)))
- (tl-val (sap-ref-word (%thread-sap thread) offset)))
- (if (eql tl-val sb!vm::no-tls-value-marker-widetag)
- (go :unbound)
- (return-from %symbol-value-in-thread
- (values (make-lisp-obj tl-val) t))))
- (return-from %symbol-value-in-thread (values nil nil))))
- :unbound
- (error "Cannot read thread-local symbol value: ~S unbound in ~S"
- symbol thread)))
+ ;; Prevent the thread from dying completely while we look for the TLS
+ ;; area...
+ (with-all-threads-lock
+ (loop
+ (if (thread-alive-p thread)
+ (let* ((epoch sb!kernel::*gc-epoch*)
+ (offset (* sb!vm:n-word-bytes
+ (sb!vm::symbol-tls-index symbol)))
+ (tl-val (sap-ref-word (%thread-sap thread) offset)))
+ (cond ((zerop offset)
+ (return (values nil :no-tls-value)))
+ ((or (eql tl-val sb!vm:no-tls-value-marker-widetag)
+ (eql tl-val sb!vm:unbound-marker-widetag))
+ (return (values nil :unbound-in-thread)))
+ (t
+ (multiple-value-bind (obj ok) (make-lisp-obj tl-val nil)
+ ;; The value we constructed may be invalid if a GC has
+ ;; occurred. That is harmless, though, since OBJ is
+ ;; either in a register or on stack, and we are
+ ;; conservative on both on GENCGC -- so a bogus object
+ ;; is safe here as long as we don't return it. If we
+ ;; ever port threads to a non-conservative GC we must
+ ;; pin the TL-VAL address before constructing OBJ, or
+ ;; make WITH-ALL-THREADS-LOCK imply WITHOUT-GCING.
+ ;;
+ ;; The reason we don't just rely on TL-VAL pinning the
+ ;; object is that the call to MAKE-LISP-OBJ may cause
+ ;; bignum allocation, at which point TL-VAL might not
+ ;; be alive anymore -- hence the epoch check.
+ (when (eq epoch sb!kernel::*gc-epoch*)
+ (if ok
+ (return (values obj :ok))
+ (return (values obj :invalid-tls-value))))))))
+ (return (values nil :thread-dead))))))
(defun %set-symbol-value-in-thread (symbol thread value)
- (tagbody
- (with-pinned-objects (value)
- ;; Prevent the dead from dying completely while we look for
- ;; the TLS area...
- (with-all-threads-lock
- (if (thread-alive-p thread)
- (let* ((offset (* sb!vm:n-word-bytes
- (sb!vm::symbol-tls-index symbol)))
- (sap (%thread-sap thread))
- (tl-val (sap-ref-word sap offset)))
- (if (eql tl-val sb!vm::no-tls-value-marker-widetag)
- (go :unbound)
- (setf (sap-ref-word sap offset)
- (get-lisp-obj-address value)))
- (return-from %set-symbol-value-in-thread (values value t)))
- (return-from %set-symbol-value-in-thread (values nil nil)))))
- :unbound
- (error "Cannot set thread-local symbol value: ~S unbound in ~S"
- symbol thread))))
+ (with-pinned-objects (value)
+ ;; Prevent the thread from dying completely while we look for the TLS
+ ;; area...
+ (with-all-threads-lock
+ (if (thread-alive-p thread)
+ (let ((offset (* sb!vm:n-word-bytes
+ (sb!vm::symbol-tls-index symbol))))
+ (cond ((zerop offset)
+ (values nil :no-tls-value))
+ (t
+ (setf (sap-ref-word (%thread-sap thread) offset)
+ (get-lisp-obj-address value))
+ (values value :ok))))
+ (values nil :thread-dead))))))
+
+(defun symbol-value-in-thread (symbol thread &optional (errorp t))
+ "Return the local value of SYMBOL in THREAD, and a secondary value of T
+on success.
+
+If the value cannot be retrieved (because the thread has exited or because it
+has no local binding for NAME) and ERRORP is true signals an error of type
+SYMBOL-VALUE-IN-THREAD-ERROR; if ERRORP is false returns a primary value of
+NIL, and a secondary value of NIL.
+
+Can also be used with SETF to change the thread-local value of SYMBOL.
+
+SYMBOL-VALUE-IN-THREAD is primarily intended as a debugging tool, and not as a
+mechanism for inter-thread communication."
+ (declare (symbol symbol) (thread thread))
+ #!+sb-thread
+ (multiple-value-bind (res status) (%symbol-value-in-thread symbol thread)
+ (if (eq :ok status)
+ (values res t)
+ (if errorp
+ (error 'symbol-value-in-thread-error
+ :name symbol
+ :thread thread
+ :info (list :read status))
+ (values nil nil))))
+ #!-sb-thread
+ (if (boundp symbol)
+ (values (symbol-value symbol) t)
+ (if errorp
+ (error 'symbol-value-in-thread-error
+ :name symbol
+ :thread thread
+ :info (list :read :unbound-in-thread))
+ (values nil nil))))
+
+(defun (setf symbol-value-in-thread) (value symbol thread &optional (errorp t))
+ (declare (symbol symbol) (thread thread))
+ #!+sb-thread
+ (multiple-value-bind (res status) (%set-symbol-value-in-thread symbol thread value)
+ (if (eq :ok status)
+ (values res t)
+ (if errorp
+ (error 'symbol-value-in-thread-error
+ :name symbol
+ :thread thread
+ :info (list :write status))
+ (values nil nil))))
+ #!-sb-thread
+ (if (boundp symbol)
+ (values (setf (symbol-value symbol) value) t)
+ (if errorp
+ (error 'symbol-value-in-thread-error
+ :name symbol
+ :thread thread
+ :info (list :write :unbound-in-thread))
+ (values nil nil))))
(defun sb!vm::locked-symbol-global-value-add (symbol-name delta)
(sb!vm::locked-symbol-global-value-add symbol-name delta))
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