"The name of the thread. Setfable.")
(def!method print-object ((thread thread) stream)
- (if (thread-name thread)
- (print-unreadable-object (thread stream :type t :identity t)
- (prin1 (thread-name thread) stream))
- (print-unreadable-object (thread stream :type t :identity t)
- ;; body is empty => there is only one space between type and
- ;; identity
- ))
- thread)
+ (print-unreadable-object (thread stream :type t :identity t)
+ (let* ((cookie (list thread))
+ (info (if (thread-alive-p thread)
+ :running
+ (multiple-value-list
+ (join-thread thread :default cookie))))
+ (state (if (eq :running info)
+ info
+ (if (eq cookie (car info))
+ :aborted
+ :finished)))
+ (values (when (eq :finished state) info)))
+ (format stream
+ "~@[~S ~]~:[~A~;~A~:[ no values~; values: ~:*~{~S~^, ~}~]~]"
+ (thread-name thread)
+ (eq :finished state)
+ state
+ values))))
(defun thread-alive-p (thread)
#!+sb-doc
(defvar *all-threads* ())
(defvar *all-threads-lock* (make-mutex :name "all threads lock"))
+(defvar *default-alloc-signal* nil)
+
(defmacro with-all-threads-lock (&body body)
- `(call-with-system-mutex (lambda () ,@body) *all-threads-lock*))
+ `(with-system-mutex (*all-threads-lock*)
+ ,@body))
(defun list-all-threads ()
#!+sb-doc
(defun current-thread-sap ()
(sb!vm::current-thread-offset-sap sb!vm::thread-this-slot))
-(declaim (inline current-thread-sap-id))
-(defun current-thread-sap-id ()
- (sap-int
- (sb!vm::current-thread-offset-sap sb!vm::thread-os-thread-slot)))
+(declaim (inline current-thread-os-thread))
+(defun current-thread-os-thread ()
+ #!+sb-thread
+ (sap-int (sb!vm::current-thread-offset-sap sb!vm::thread-os-thread-slot))
+ #!-sb-thread
+ 0)
(defun init-initial-thread ()
(/show0 "Entering INIT-INITIAL-THREAD")
(let ((initial-thread (%make-thread :name "initial thread"
:%alive-p t
- :os-thread (current-thread-sap-id))))
+ :os-thread (current-thread-os-thread))))
(setq *current-thread* initial-thread)
;; Either *all-threads* is empty or it contains exactly one thread
;; in case we are in reinit since saving core with multiple
;; threads doesn't work.
(setq *all-threads* (list initial-thread))))
+\f
-;;;;
+;;;; Aliens, low level stuff
#!+sb-thread
(progn
(defun sb!vm::current-thread-offset-sap (n)
(declare (type (unsigned-byte 27) n))
(sb!vm::current-thread-offset-sap n))
+\f
+
+;;;; Spinlocks
(declaim (inline get-spinlock release-spinlock))
-;; Should always be called with interrupts disabled.
+;;; Should always be called with interrupts disabled.
(defun get-spinlock (spinlock)
(declare (optimize (speed 3) (safety 0)))
(let* ((new *current-thread*)
(error "Recursive lock attempt on ~S." spinlock))
#!+sb-thread
(flet ((cas ()
- (unless (sb!ext:compare-and-swap (spinlock-value spinlock) nil new)
- (return-from get-spinlock t))))
+ (if (sb!ext:compare-and-swap (spinlock-value spinlock) nil new)
+ (thread-yield)
+ (return-from get-spinlock t))))
(if (and (not *interrupts-enabled*) *allow-with-interrupts*)
- ;; If interrupts are enabled, but we are allowed to enabled them,
- ;; check for pending interrupts every once in a while.
+ ;; If interrupts are disabled, but we are allowed to
+ ;; enabled them, check for pending interrupts every once
+ ;; in a while.
(loop
(loop repeat 128 do (cas)) ; 128 is arbitrary here
(sb!unix::%check-interrupts))
(defun release-spinlock (spinlock)
(declare (optimize (speed 3) (safety 0)))
- (setf (spinlock-value spinlock) nil)
- nil)
-
-;;;; mutexes
+ ;; On x86 and x86-64 we can get away with no memory barriers, (see
+ ;; Linux kernel mailing list "spin_unlock optimization(i386)"
+ ;; thread, summary at
+ ;; http://kt.iserv.nl/kernel-traffic/kt19991220_47.html#1.
+ ;;
+ ;; If the compiler may reorder this with other instructions, insert
+ ;; compiler barrier here.
+ ;;
+ ;; FIXME: this does not work on SMP Pentium Pro and OOSTORE systems,
+ ;; neither on most non-x86 architectures (but we don't have threads
+ ;; on those).
+ (setf (spinlock-value spinlock) nil))
+\f
+
+;;;; Mutexes
#!+sb-doc
(setf (fdocumentation 'make-mutex 'function)
(defconstant +lock-taken+ 1)
(defconstant +lock-contested+ 2))
+(defun mutex-owner (mutex)
+ "Current owner of the mutex, NIL if the mutex is free. Naturally,
+this is racy by design (another thread may acquire the mutex after
+this function returns), it is intended for informative purposes. For
+testing whether the current thread is holding a mutex see
+HOLDING-MUTEX-P."
+ ;; Make sure to get the current value.
+ (sb!ext:compare-and-swap (mutex-%owner mutex) nil nil))
+
(defun get-mutex (mutex &optional (new-owner *current-thread*) (waitp t))
#!+sb-doc
"Acquire MUTEX for NEW-OWNER, which must be a thread or NIL. If
#!-sb-thread (ignore waitp))
(unless new-owner
(setq new-owner *current-thread*))
- (when (eql new-owner (mutex-%owner mutex))
- (error "Recursive lock attempt ~S." mutex))
+ (let ((old (mutex-%owner mutex)))
+ (when (eq new-owner old)
+ (error "Recursive lock attempt ~S." mutex))
+ #!-sb-thread
+ (when old
+ (error "Strange deadlock on ~S in an unithreaded build?" mutex)))
+ #!-sb-thread
+ (setf (mutex-%owner mutex) new-owner)
#!+sb-thread
(progn
;; FIXME: Lutexes do not currently support deadlines, as at least
(setf (mutex-%owner mutex) new-owner)
t)
#!-sb-lutex
+ ;; This is a direct tranlation of the Mutex 2 algorithm from
+ ;; "Futexes are Tricky" by Ulrich Drepper.
(let ((old (sb!ext:compare-and-swap (mutex-state mutex)
+lock-free+
+lock-taken+)))
RELEASE-MUTEX is not interrupt safe: interrupts should be disabled
around calls to it.
-Signals a WARNING is current thread is not the current owner of the
+Signals a WARNING if current thread is not the current owner of the
mutex."
(declare (type mutex mutex))
;; Order matters: set owner to NIL before releasing state.
(with-lutex-address (lutex (mutex-lutex mutex))
(%lutex-unlock lutex))
#!-sb-lutex
+ ;; FIXME: once ATOMIC-INCF supports struct slots with word sized
+ ;; unsigned-byte type this can be used:
+ ;;
+ ;; (let ((old (sb!ext:atomic-incf (mutex-state mutex) -1)))
+ ;; (unless (eql old +lock-free+)
+ ;; (setf (mutex-state mutex) +lock-free+)
+ ;; (with-pinned-objects (mutex)
+ ;; (futex-wake (mutex-state-address mutex) 1))))
(let ((old (sb!ext:compare-and-swap (mutex-state mutex)
+lock-taken+ +lock-free+)))
(when (eql old +lock-contested+)
(with-pinned-objects (mutex)
(futex-wake (mutex-state-address mutex) 1))))
nil))
+\f
-;;;; waitqueues/condition variables
+;;;; Waitqueues/condition variables
(defstruct (waitqueue (:constructor %make-waitqueue))
#!+sb-doc
(assert mutex)
#!-sb-thread (error "Not supported in unithread builds.")
#!+sb-thread
- (let ((owner (mutex-%owner mutex)))
+ (let ((me *current-thread*))
+ (assert (eq me (mutex-%owner mutex)))
(/show0 "CONDITION-WAITing")
#!+sb-lutex
- (progn
- ;; FIXME: This doesn't look interrupt safe!
- (setf (mutex-%owner mutex) nil)
- (with-lutex-address (queue-lutex-address (waitqueue-lutex queue))
- (with-lutex-address (mutex-lutex-address (mutex-lutex mutex))
- (%lutex-wait queue-lutex-address mutex-lutex-address)))
- (setf (mutex-%owner mutex) owner))
+ ;; Need to disable interrupts so that we don't miss setting the
+ ;; owner on our way out. (pthread_cond_wait handles the actual
+ ;; re-acquisition.)
+ (without-interrupts
+ (unwind-protect
+ (progn
+ (setf (mutex-%owner mutex) nil)
+ (with-lutex-address (queue-lutex-address (waitqueue-lutex queue))
+ (with-lutex-address (mutex-lutex-address (mutex-lutex mutex))
+ (with-local-interrupts
+ (%lutex-wait queue-lutex-address mutex-lutex-address)))))
+ (setf (mutex-%owner mutex) me)))
#!-sb-lutex
- (unwind-protect
- (let ((me *current-thread*))
- ;; FIXME: should we do something to ensure that the result
- ;; of this setf is visible to all CPUs?
- (setf (waitqueue-data queue) me)
- (release-mutex mutex)
- ;; Now we go to sleep using futex-wait. If anyone else
- ;; manages to grab MUTEX and call CONDITION-NOTIFY during
- ;; this comment, it will change queue->data, and so
- ;; futex-wait returns immediately instead of sleeping.
- ;; Ergo, no lost wakeup. We may get spurious wakeups,
- ;; but that's ok.
- (multiple-value-bind (to-sec to-usec) (decode-timeout nil)
- (when (= 1 (with-pinned-objects (queue me)
- (futex-wait (waitqueue-data-address queue)
- (get-lisp-obj-address me)
- (or to-sec -1) ;; our way if saying "no timeout"
- (or to-usec 0))))
- (signal-deadline))))
- ;; If we are interrupted while waiting, we should do these things
- ;; before returning. Ideally, in the case of an unhandled signal,
- ;; we should do them before entering the debugger, but this is
- ;; better than nothing.
- (get-mutex mutex owner))))
+ ;; Need to disable interrupts so that we don't miss grabbing the
+ ;; mutex on our way out.
+ (without-interrupts
+ (unwind-protect
+ (let ((me *current-thread*))
+ ;; This setf becomes visible to other CPUS due to the
+ ;; usual memory barrier semantics of lock
+ ;; acquire/release.
+ (setf (waitqueue-data queue) me)
+ (release-mutex mutex)
+ ;; Now we go to sleep using futex-wait. If anyone else
+ ;; manages to grab MUTEX and call CONDITION-NOTIFY during
+ ;; this comment, it will change queue->data, and so
+ ;; futex-wait returns immediately instead of sleeping.
+ ;; Ergo, no lost wakeup. We may get spurious wakeups, but
+ ;; that's ok.
+ (multiple-value-bind (to-sec to-usec) (decode-timeout nil)
+ (when (= 1 (with-pinned-objects (queue me)
+ (allow-with-interrupts
+ (futex-wait (waitqueue-data-address queue)
+ (get-lisp-obj-address me)
+ ;; our way if saying "no
+ ;; timeout":
+ (or to-sec -1)
+ (or to-usec 0)))))
+ (signal-deadline))))
+ ;; If we are interrupted while waiting, we should do these
+ ;; things before returning. Ideally, in the case of an
+ ;; unhandled signal, we should do them before entering the
+ ;; debugger, but this is better than nothing.
+ (get-mutex mutex)))))
(defun condition-notify (queue &optional (n 1))
#!+sb-doc
- "Notify N threads waiting on QUEUE."
+ "Notify N threads waiting on QUEUE. The same mutex that is used in
+the correspoinding condition-wait must be held by this thread during
+this call."
#!-sb-thread (declare (ignore queue n))
#!-sb-thread (error "Not supported in unithread builds.")
#!+sb-thread
#!+sb-doc
"Notify all threads waiting on QUEUE."
(condition-notify queue
- ;; On a 64-bit platform truncating M-P-F to an int results
- ;; in -1, which wakes up only one thread.
+ ;; On a 64-bit platform truncating M-P-F to an int
+ ;; results in -1, which wakes up only one thread.
(ldb (byte 29 0)
most-positive-fixnum)))
+\f
-;;;; semaphores
+;;;; Semaphores
(defstruct (semaphore (:constructor %make-semaphore (name %count)))
#!+sb-doc
future."
(name nil :type (or null simple-string))
(%count 0 :type (integer 0))
+ (waitcount 0 :type (integer 0))
(mutex (make-mutex))
(queue (make-waitqueue)))
#!+sb-doc
"Decrement the count of SEMAPHORE if the count would not be
negative. Else blocks until the semaphore can be decremented."
- ;; a more direct implementation based directly on futexes should be
- ;; possible
- (with-mutex ((semaphore-mutex semaphore))
- (loop until (> (semaphore-%count semaphore) 0)
- do (condition-wait (semaphore-queue semaphore) (semaphore-mutex semaphore))
- finally (decf (semaphore-%count semaphore)))))
+ ;; A more direct implementation based directly on futexes should be
+ ;; possible.
+ ;;
+ ;; We need to disable interrupts so that we don't forget to
+ ;; decrement the waitcount (which would happen if an asynch
+ ;; interrupt should catch us on our way out from the loop.)
+ (with-system-mutex ((semaphore-mutex semaphore) :allow-with-interrupts t)
+ ;; Quick check: is it positive? If not, enter the wait loop.
+ (let ((count (semaphore-%count semaphore)))
+ (if (plusp count)
+ (setf (semaphore-%count semaphore) (1- count))
+ (unwind-protect
+ (progn
+ (incf (semaphore-waitcount semaphore))
+ (loop until (plusp (setf count (semaphore-%count semaphore)))
+ do (condition-wait (semaphore-queue semaphore)
+ (semaphore-mutex semaphore)))
+ (setf (semaphore-%count semaphore) (1- count)))
+ (decf (semaphore-waitcount semaphore)))))))
(defun signal-semaphore (semaphore &optional (n 1))
#!+sb-doc
"Increment the count of SEMAPHORE by N. If there are threads waiting
on this semaphore, then N of them is woken up."
(declare (type (integer 1) n))
- (with-mutex ((semaphore-mutex semaphore))
- (when (= n (incf (semaphore-%count semaphore) n))
- (condition-notify (semaphore-queue semaphore) n))))
+ ;; Need to disable interrupts so that we don't lose a wakeup after
+ ;; we have incremented the count.
+ (with-system-mutex ((semaphore-mutex semaphore))
+ (let ((waitcount (semaphore-waitcount semaphore))
+ (count (incf (semaphore-%count semaphore) n)))
+ (when (plusp waitcount)
+ (condition-notify (semaphore-queue semaphore) (min waitcount count))))))
+\f
-;;;; job control, independent listeners
+;;;; Job control, independent listeners
(defstruct session
(lock (make-mutex :name "session lock"))
(defvar *session* nil)
-;;; the debugger itself tries to acquire the session lock, don't let
+;;; The debugger itself tries to acquire the session lock, don't let
;;; funny situations (like getting a sigint while holding the session
-;;; lock) occur
+;;; lock) occur. At the same time we need to allow interrupts while
+;;; *waiting* for the session lock for things like GET-FOREGROUND to
+;;; be interruptible.
+;;;
+;;; Take care: we sometimes need to obtain the session lock while
+;;; holding on to *ALL-THREADS-LOCK*, so we must _never_ obtain it
+;;; _after_ getting a session lock! (Deadlock risk.)
+;;;
+;;; FIXME: It would be good to have ordered locks to ensure invariants
+;;; like the above.
(defmacro with-session-lock ((session) &body body)
- `(call-with-system-mutex (lambda () ,@body) (session-lock ,session)))
+ `(with-system-mutex ((session-lock ,session) :allow-with-interrupts t)
+ ,@body))
(defun new-session ()
(make-session :threads (list *current-thread*)
#!+sb-thread
(defun handle-thread-exit (thread)
(/show0 "HANDLING THREAD EXIT")
- ;; We're going down, can't handle interrupts sanely anymore.
- ;; GC remains enabled.
- (block-deferrable-signals)
;; Lisp-side cleanup
(with-all-threads-lock
(setf (thread-%alive-p thread) nil)
(sb!impl::toplevel-repl nil)
(sb!int:flush-standard-output-streams))))))
(make-thread #'thread-repl))))
+\f
-;;;; the beef
+;;;; The beef
(defun make-thread (function &key name)
#!+sb-doc
;; of Allegro's *cl-default-special-bindings*, as that is at
;; least accessible to users to secure their own libraries.
;; --njf, 2006-07-15
- (let ((*current-thread* thread)
- (*restart-clusters* nil)
- (*handler-clusters* nil)
- (*condition-restarts* nil)
- (sb!impl::*deadline* nil)
- (sb!impl::*step-out* nil)
- ;; internal printer variables
- (sb!impl::*previous-case* nil)
- (sb!impl::*previous-readtable-case* nil)
- (empty (vector))
- (sb!impl::*merge-sort-temp-vector* empty)
- (sb!impl::*zap-array-data-temp* empty)
- (sb!impl::*internal-symbol-output-fun* nil)
- (sb!impl::*descriptor-handlers* nil)) ; serve-event
- (setf (thread-os-thread thread) (current-thread-sap-id))
+ ;;
+ ;; As it is, this lambda must not cons until we are ready
+ ;; to run GC. Be very careful.
+ (let* ((*current-thread* thread)
+ (*restart-clusters* nil)
+ (*handler-clusters* (sb!kernel::initial-handler-clusters))
+ (*condition-restarts* nil)
+ (sb!impl::*deadline* nil)
+ (sb!impl::*step-out* nil)
+ ;; internal printer variables
+ (sb!impl::*previous-case* nil)
+ (sb!impl::*previous-readtable-case* nil)
+ (empty (vector))
+ (sb!impl::*merge-sort-temp-vector* empty)
+ (sb!impl::*zap-array-data-temp* empty)
+ (sb!impl::*internal-symbol-output-fun* nil)
+ (sb!impl::*descriptor-handlers* nil)) ; serve-event
+ ;; Binding from C
+ (setf sb!vm:*alloc-signal* *default-alloc-signal*)
+ (setf (thread-os-thread thread) (current-thread-os-thread))
(with-mutex ((thread-result-lock thread))
(with-all-threads-lock
(push thread *all-threads*))
(format nil
"~~@<Terminate this thread (~A)~~@:>"
*current-thread*))
- (unwind-protect
- (progn
- ;; now that most things have a chance to
- ;; work properly without messing up other
- ;; threads, it's time to enable signals
- (sb!unix::reset-signal-mask)
- (setf (thread-result thread)
- (cons t
- (multiple-value-list
- (funcall real-function)))))
- (handle-thread-exit thread)))))))
+ (without-interrupts
+ (unwind-protect
+ (with-local-interrupts
+ ;; Now that most things have a chance
+ ;; to work properly without messing up
+ ;; other threads, it's time to enable
+ ;; signals.
+ (sb!unix::unblock-deferrable-signals)
+ (setf (thread-result thread)
+ (cons t
+ (multiple-value-list
+ (funcall real-function))))
+ ;; Try to block deferrables. An
+ ;; interrupt may unwind it, but for a
+ ;; normal exit it prevents interrupt
+ ;; loss.
+ (block-deferrable-signals))
+ ;; We're going down, can't handle interrupts
+ ;; sanely anymore. GC remains enabled.
+ (block-deferrable-signals)
+ ;; We don't want to run interrupts in a dead
+ ;; thread when we leave WITHOUT-INTERRUPTS.
+ ;; This potentially causes important
+ ;; interupts to be lost: SIGINT comes to
+ ;; mind.
+ (setq *interrupt-pending* nil)
+ (handle-thread-exit thread))))))))
(values))))
+ ;; If the starting thread is stopped for gc before it signals the
+ ;; semaphore then we'd be stuck.
+ (assert (not *gc-inhibit*))
;; Keep INITIAL-FUNCTION pinned until the child thread is
- ;; initialized properly.
- (with-pinned-objects (initial-function)
- (let ((os-thread
- (%create-thread
- (get-lisp-obj-address initial-function))))
- (when (zerop os-thread)
- (error "Can't create a new thread"))
- (wait-on-semaphore setup-sem)
- thread))))
+ ;; initialized properly. Wrap the whole thing in
+ ;; WITHOUT-INTERRUPTS because we pass INITIAL-FUNCTION to another
+ ;; thread.
+ (without-interrupts
+ (with-pinned-objects (initial-function)
+ (let ((os-thread
+ (%create-thread
+ (get-lisp-obj-address initial-function))))
+ (when (zerop os-thread)
+ (error "Can't create a new thread"))
+ (wait-on-semaphore setup-sem)
+ thread)))))
(define-condition join-thread-error (error)
((thread :reader join-thread-error-thread :initarg :thread))
"Suspend current thread until THREAD exits. Returns the result
values of the thread function. If the thread does not exit normally,
return DEFAULT if given or else signal JOIN-THREAD-ERROR."
- (with-mutex ((thread-result-lock thread))
+ (with-system-mutex ((thread-result-lock thread) :allow-with-interrupts t)
(cond ((car (thread-result thread))
- (values-list (cdr (thread-result thread))))
+ (return-from join-thread
+ (values-list (cdr (thread-result thread)))))
(defaultp
- default)
- (t
- (error 'join-thread-error :thread thread)))))
+ (return-from join-thread default))))
+ (error 'join-thread-error :thread thread))
(defun destroy-thread (thread)
#!+sb-doc
"The thread that was not interrupted.")
(defmacro with-interruptions-lock ((thread) &body body)
- `(call-with-system-mutex (lambda () ,@body) (thread-interruptions-lock ,thread)))
+ `(with-system-mutex ((thread-interruptions-lock ,thread))
+ ,@body))
-;; Called from the signal handler in C.
+;;; Called from the signal handler in C.
(defun run-interruption ()
(in-interruption ()
(loop
- (let ((interruption (with-interruptions-lock (*current-thread*)
- (pop (thread-interruptions *current-thread*)))))
- (if interruption
- (with-interrupts
- (funcall interruption))
- (return))))))
-
-;; The order of interrupt execution is peculiar. If thread A
-;; interrupts thread B with I1, I2 and B for some reason receives I1
-;; when FUN2 is already on the list, then it is FUN2 that gets to run
-;; first. But when FUN2 is run SIG_INTERRUPT_THREAD is enabled again
-;; and I2 hits pretty soon in FUN2 and run FUN1. This is of course
-;; just one scenario, and the order of thread interrupt execution is
-;; undefined.
+ (let ((interruption (with-interruptions-lock (*current-thread*)
+ (pop (thread-interruptions *current-thread*)))))
+ ;; Resignalling after popping one works fine, because from the
+ ;; OS's point of view we have returned from the signal handler
+ ;; (thanks to arrange_return_to_lisp_function) so at least one
+ ;; more signal will be delivered.
+ (when (thread-interruptions *current-thread*)
+ (signal-interrupt-thread (thread-os-thread *current-thread*)))
+ (if interruption
+ (with-interrupts
+ (funcall interruption))
+ (return))))))
+
+;;; The order of interrupt execution is peculiar. If thread A
+;;; interrupts thread B with I1, I2 and B for some reason receives I1
+;;; when FUN2 is already on the list, then it is FUN2 that gets to run
+;;; first. But when FUN2 is run SIG_INTERRUPT_THREAD is enabled again
+;;; and I2 hits pretty soon in FUN2 and run FUN1. This is of course
+;;; just one scenario, and the order of thread interrupt execution is
+;;; undefined.
(defun interrupt-thread (thread function)
#!+sb-doc
"Interrupt the live THREAD and make it run FUNCTION. A moderate
SB-EXT:QUIT - the usual cleanup forms will be evaluated"
(interrupt-thread thread 'sb!ext:quit))
-;;; internal use only. If you think you need to use this, either you
-;;; are an SBCL developer, are doing something that you should discuss
-;;; with an SBCL developer first, or are doing something that you
-;;; should probably discuss with a professional psychiatrist first
-#!+sb-thread
-(defun thread-sap-for-id (id)
- (let ((thread-sap (alien-sap (extern-alien "all_threads" (* t)))))
- (loop
- (when (sap= thread-sap (int-sap 0)) (return nil))
- (let ((os-thread (sap-ref-word thread-sap
- (* sb!vm:n-word-bytes
- sb!vm::thread-os-thread-slot))))
- (when (= os-thread id) (return thread-sap))
- (setf thread-sap
- (sap-ref-sap thread-sap (* sb!vm:n-word-bytes
- sb!vm::thread-next-slot)))))))
-
(define-alien-routine "thread_yield" int)
#!+sb-doc
(setf (fdocumentation 'thread-yield 'function)
"Yield the processor to other threads.")
+;;; internal use only. If you think you need to use these, either you
+;;; are an SBCL developer, are doing something that you should discuss
+;;; with an SBCL developer first, or are doing something that you
+;;; should probably discuss with a professional psychiatrist first
#!+sb-thread
-(defun symbol-value-in-thread (symbol thread-sap)
- (let* ((index (sb!vm::symbol-tls-index symbol))
- (tl-val (sap-ref-word thread-sap
- (* sb!vm:n-word-bytes index))))
- (if (eql tl-val sb!vm::no-tls-value-marker-widetag)
- (sb!vm::symbol-global-value symbol)
- (make-lisp-obj tl-val))))
+(progn
+ (defun %thread-sap (thread)
+ (let ((thread-sap (alien-sap (extern-alien "all_threads" (* t))))
+ (target (thread-os-thread thread)))
+ (loop
+ (when (sap= thread-sap (int-sap 0)) (return nil))
+ (let ((os-thread (sap-ref-word thread-sap
+ (* sb!vm:n-word-bytes
+ sb!vm::thread-os-thread-slot))))
+ (when (= os-thread target) (return thread-sap))
+ (setf thread-sap
+ (sap-ref-sap thread-sap (* sb!vm:n-word-bytes
+ 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)))
+
+ (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))))
(defun sb!vm::locked-symbol-global-value-add (symbol-name delta)
(sb!vm::locked-symbol-global-value-add symbol-name delta))
+\f
-;;; Stepping
+;;;; Stepping
(defun thread-stepping ()
(make-lisp-obj
projects / sbcl.git / blobdiff