(cell-error-name condition)
(thread-error-thread condition)
(ecase problem
- (:unbound "the symbol is unbound in thread.")
- (:dead "the thread has exited."))))))
+ (: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 the
-symbol being unbound in target thread, or the target thread having exited. The
-offending symbol can be accessed using CELL-ERROR-NAME, and the offending
-thread using THREAD-ERROR-THREAD."))
+ "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)
(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)
(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
sb!vm::thread-next-slot)))))))
(defun %symbol-value-in-thread (symbol thread)
- ;; Prevent the thread from dying completely while we look for the TLS
- ;; area...
+ ;; 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)))
- (tl-val (sap-ref-word (%thread-sap thread) offset)))
- (if (eql tl-val sb!vm::no-tls-value-marker-widetag)
- (values nil :unbound)
- (values (make-lisp-obj tl-val) :bound)))
- (values nil :dead))))
+ (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)
(with-pinned-objects (value)
;; 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)))
- (cond ((eql tl-val sb!vm::no-tls-value-marker-widetag)
- (values nil :unbound))
+ (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 sap offset)
+ (setf (sap-ref-word (%thread-sap thread) offset)
(get-lisp-obj-address value))
- (values value :bound))))
- (values nil :dead))))))
+ (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
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 form inter-thread communication."
+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 :bound status)
+ (if (eq :ok status)
(values res t)
(if errorp
(error 'symbol-value-in-thread-error
(error 'symbol-value-in-thread-error
:name symbol
:thread thread
- :info (list :read :unbound))
+ :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 :bound status)
+ (if (eq :ok status)
(values res t)
(if errorp
(error 'symbol-value-in-thread-error
(error 'symbol-value-in-thread-error
:name symbol
:thread thread
- :info (list :write :unbound))
+ :info (list :write :unbound-in-thread))
(values nil nil))))
(defun sb!vm::locked-symbol-global-value-add (symbol-name delta)
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