forked from dmitryvk/sbcl-win32-threads
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target-thread.lisp
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target-thread.lisp
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;;;; support for threads in the target machine
;;;; 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")
;;; 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)
;;; are treated as references.
;;; set the doc here because in early-thread FDOCUMENTATION is not
;;; available, yet
#!+sb-doc
(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.")
(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)
(defun thread-alive-p (thread)
#!+sb-doc
"Check if THREAD is running."
(thread-%alive-p thread))
;; A thread is eligible for gc iff it has finished and there are no
;; more references to it. This list is supposed to keep a reference to
;; all running threads.
(defvar *all-threads* ())
(defvar *all-threads-lock* (make-mutex :name "all threads lock"))
(defmacro with-all-threads-lock (&body body)
`(with-system-mutex (*all-threads-lock*)
,@body))
(defun list-all-threads ()
#!+sb-doc
"Return a list of the live threads."
(with-all-threads-lock
(copy-list *all-threads*)))
(declaim (inline current-thread-sap))
(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)))
(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))))
(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))))
;;;;
#!+sb-thread
(progn
;; FIXME it would be good to define what a thread id is or isn't
;; (our current assumption is that it's a fixnum). It so happens
;; that on Linux it's a pid, but it might not be on posix thread
;; implementations.
(define-alien-routine ("create_thread" %create-thread)
unsigned-long (lisp-fun-address unsigned-long))
(define-alien-routine "signal_interrupt_thread"
integer (os-thread unsigned-long))
(define-alien-routine "block_deferrable_signals"
void)
#!+sb-lutex
(progn
(declaim (inline %lutex-init %lutex-wait %lutex-wake
%lutex-lock %lutex-unlock))
(define-alien-routine ("lutex_init" %lutex-init)
int (lutex unsigned-long))
(define-alien-routine ("lutex_wait" %lutex-wait)
int (queue-lutex unsigned-long) (mutex-lutex unsigned-long))
(define-alien-routine ("lutex_wake" %lutex-wake)
int (lutex unsigned-long) (n int))
(define-alien-routine ("lutex_lock" %lutex-lock)
int (lutex unsigned-long))
(define-alien-routine ("lutex_trylock" %lutex-trylock)
int (lutex unsigned-long))
(define-alien-routine ("lutex_unlock" %lutex-unlock)
int (lutex unsigned-long))
(define-alien-routine ("lutex_destroy" %lutex-destroy)
int (lutex unsigned-long))
;; FIXME: Defining a whole bunch of alien-type machinery just for
;; passing primitive lutex objects directly to foreign functions
;; doesn't seem like fun right now. So instead we just manually
;; pin the lutex, get its address, and let the callee untag it.
(defmacro with-lutex-address ((name lutex) &body body)
`(let ((,name ,lutex))
(with-pinned-objects (,name)
(let ((,name (get-lisp-obj-address ,name)))
,@body))))
(defun make-lutex ()
(/show0 "Entering MAKE-LUTEX")
;; Suppress GC until the lutex has been properly registered with
;; the GC.
(without-gcing
(let ((lutex (sb!vm::%make-lutex)))
(/show0 "LUTEX=..")
(/hexstr lutex)
(with-lutex-address (lutex lutex)
(%lutex-init lutex))
lutex))))
#!-sb-lutex
(progn
(declaim (inline futex-wait %futex-wait futex-wake))
(define-alien-routine ("futex_wait" %futex-wait)
int (word unsigned-long) (old-value unsigned-long)
(to-sec long) (to-usec unsigned-long))
(defun futex-wait (word old to-sec to-usec)
(with-interrupts
(%futex-wait word old to-sec to-usec)))
(define-alien-routine "futex_wake"
int (word unsigned-long) (n unsigned-long))))
;;; used by debug-int.lisp to access interrupt contexts
#!-(or sb-fluid sb-thread) (declaim (inline sb!vm::current-thread-offset-sap))
#!-sb-thread
(defun sb!vm::current-thread-offset-sap (n)
(declare (type (unsigned-byte 27) n))
(sap-ref-sap (alien-sap (extern-alien "all_threads" (* t)))
(* n sb!vm:n-word-bytes)))
#!+sb-thread
(defun sb!vm::current-thread-offset-sap (n)
(declare (type (unsigned-byte 27) n))
(sb!vm::current-thread-offset-sap n))
(declaim (inline get-spinlock release-spinlock))
;; Should always be called with interrupts disabled.
(defun get-spinlock (spinlock)
(declare (optimize (speed 3) (safety 0)))
(let* ((new *current-thread*)
(old (sb!ext:compare-and-swap (spinlock-value spinlock) nil new)))
(when old
(when (eq old new)
(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 (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.
(loop
(loop repeat 128 do (cas)) ; 128 is arbitrary here
(sb!unix::%check-interrupts))
(loop (cas)))))
t))
(defun release-spinlock (spinlock)
(declare (optimize (speed 3) (safety 0)))
(setf (spinlock-value spinlock) nil)
nil)
;;;; mutexes
#!+sb-doc
(setf (fdocumentation 'make-mutex 'function)
"Create a mutex."
(fdocumentation 'mutex-name 'function)
"The name of the mutex. Setfable.")
#!+(and sb-thread (not sb-lutex))
(progn
(define-structure-slot-addressor mutex-state-address
:structure mutex
:slot state)
;; Important: current code assumes these are fixnums or other
;; lisp objects that don't need pinning.
(defconstant +lock-free+ 0)
(defconstant +lock-taken+ 1)
(defconstant +lock-contested+ 2))
(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
NEW-OWNER is NIL, it defaults to the current thread. If WAITP is
non-NIL and the mutex is in use, sleep until it is available.
Note: using GET-MUTEX to assign a MUTEX to another thread then the
current one is not recommended, and liable to be deprecated.
GET-MUTEX is not interrupt safe. The correct way to call it is:
(WITHOUT-INTERRUPTS
...
(ALLOW-WITH-INTERRUPTS (GET-MUTEX ...))
...)
WITHOUT-INTERRUPTS is necessary to avoid an interrupt unwinding the
call while the mutex is in an inconsistent state while
ALLOW-WITH-INTERRUPTS allows the call to be interrupted from sleep.
It is recommended that you use WITH-MUTEX instead of calling GET-MUTEX
directly."
(declare (type mutex mutex) (optimize (speed 3))
#!-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))
#!+sb-thread
(progn
;; FIXME: Lutexes do not currently support deadlines, as at least
;; on Darwin pthread_foo_timedbar functions are not supported:
;; this means that we probably need to use the Carbon multiprocessing
;; functions on Darwin.
;;
;; FIXME: This is definitely not interrupt safe: what happens if
;; we get hit (1) during the lutex calls (ok, they may be safe,
;; but has that been checked?) (2) after the lutex call, but
;; before setting the mutex owner.
#!+sb-lutex
(when (zerop (with-lutex-address (lutex (mutex-lutex mutex))
(if waitp
(with-interrupts (%lutex-lock lutex))
(%lutex-trylock lutex))))
(setf (mutex-%owner mutex) new-owner)
t)
#!-sb-lutex
(let ((old (sb!ext:compare-and-swap (mutex-state mutex)
+lock-free+
+lock-taken+)))
(unless (or (eql +lock-free+ old) (not waitp))
(tagbody
:retry
(when (or (eql +lock-contested+ old)
(not (eql +lock-free+
(sb!ext:compare-and-swap (mutex-state mutex)
+lock-taken+
+lock-contested+))))
;; Wait on the contested lock.
(multiple-value-bind (to-sec to-usec) (decode-timeout nil)
(when (= 1 (with-pinned-objects (mutex)
(futex-wait (mutex-state-address mutex)
(get-lisp-obj-address +lock-contested+)
(or to-sec -1)
(or to-usec 0))))
(signal-deadline))))
(setf old (sb!ext:compare-and-swap (mutex-state mutex)
+lock-free+
+lock-contested+))
;; Did we get it?
(unless (eql +lock-free+ old)
(go :retry))))
(cond ((eql +lock-free+ old)
(let ((prev (sb!ext:compare-and-swap (mutex-%owner mutex)
nil new-owner)))
(when prev
(bug "Old owner in free mutex: ~S" prev))
t))
(waitp
(bug "Failed to acquire lock with WAITP."))))))
(defun release-mutex (mutex)
#!+sb-doc
"Release MUTEX by setting it to NIL. Wake up threads waiting for
this mutex.
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
mutex."
(declare (type mutex mutex))
;; Order matters: set owner to NIL before releasing state.
(let* ((self *current-thread*)
(old-owner (sb!ext:compare-and-swap (mutex-%owner mutex) self nil)))
(unless (eql self old-owner)
(warn "Releasing ~S, owned by another thread: ~S" mutex old-owner)
(setf (mutex-%owner mutex) nil)))
#!+sb-thread
(progn
#!+sb-lutex
(with-lutex-address (lutex (mutex-lutex mutex))
(%lutex-unlock lutex))
#!-sb-lutex
(let ((old (sb!ext:compare-and-swap (mutex-state mutex)
+lock-taken+ +lock-free+)))
(when (eql old +lock-contested+)
(sb!ext:compare-and-swap (mutex-state mutex)
+lock-contested+ +lock-free+)
(with-pinned-objects (mutex)
(futex-wake (mutex-state-address mutex) 1))))
nil))
;;;; waitqueues/condition variables
(defstruct (waitqueue (:constructor %make-waitqueue))
#!+sb-doc
"Waitqueue type."
(name nil :type (or null simple-string))
#!+(and sb-lutex sb-thread)
(lutex (make-lutex))
#!-sb-lutex
(data nil))
(defun make-waitqueue (&key name)
#!+sb-doc
"Create a waitqueue."
(%make-waitqueue :name name))
#!+sb-doc
(setf (fdocumentation 'waitqueue-name 'function)
"The name of the waitqueue. Setfable.")
#!+(and sb-thread (not sb-lutex))
(define-structure-slot-addressor waitqueue-data-address
:structure waitqueue
:slot data)
(defun condition-wait (queue mutex)
#!+sb-doc
"Atomically release MUTEX and enqueue ourselves on QUEUE. Another
thread may subsequently notify us using CONDITION-NOTIFY, at which
time we reacquire MUTEX and return to the caller."
#!-sb-thread (declare (ignore queue))
(assert mutex)
#!-sb-thread (error "Not supported in unithread builds.")
#!+sb-thread
(let ((owner (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))
#!-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))))
(defun condition-notify (queue &optional (n 1))
#!+sb-doc
"Notify N threads waiting on QUEUE."
#!-sb-thread (declare (ignore queue n))
#!-sb-thread (error "Not supported in unithread builds.")
#!+sb-thread
(declare (type (and fixnum (integer 1)) n))
(/show0 "Entering CONDITION-NOTIFY")
#!+sb-thread
(progn
#!+sb-lutex
(with-lutex-address (lutex (waitqueue-lutex queue))
(%lutex-wake lutex n))
;; no problem if >1 thread notifies during the comment in
;; condition-wait: as long as the value in queue-data isn't the
;; waiting thread's id, it matters not what it is
;; XXX we should do something to ensure that the result of this setf
;; is visible to all CPUs
#!-sb-lutex
(let ((me *current-thread*))
(progn
(setf (waitqueue-data queue) me)
(with-pinned-objects (queue)
(futex-wake (waitqueue-data-address queue) n))))))
(defun condition-broadcast (queue)
#!+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.
(ldb (byte 29 0)
most-positive-fixnum)))
;;;; semaphores
(defstruct (semaphore (:constructor %make-semaphore (name %count)))
#!+sb-doc
"Semaphore type. The fact that a SEMAPHORE is a STRUCTURE-OBJECT
should be considered an implementation detail, and may change in the
future."
(name nil :type (or null simple-string))
(%count 0 :type (integer 0))
(mutex (make-mutex))
(queue (make-waitqueue)))
(setf (fdocumentation 'semaphore-name 'function)
"The name of the semaphore INSTANCE. Setfable.")
(declaim (inline semaphore-count))
(defun semaphore-count (instance)
"Returns the current count of the semaphore INSTANCE."
(semaphore-%count instance))
(defun make-semaphore (&key name (count 0))
#!+sb-doc
"Create a semaphore with the supplied COUNT and NAME."
(%make-semaphore name count))
(defun wait-on-semaphore (semaphore)
#!+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)))))
(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))))
;;;; job control, independent listeners
(defstruct session
(lock (make-mutex :name "session lock"))
(threads nil)
(interactive-threads nil)
(interactive-threads-queue (make-waitqueue)))
(defvar *session* nil)
;;; The debugger itself tries to acquire the session lock, don't let
;;; funny situations (like getting a sigint while holding the session
;;; 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)
`(with-system-mutex ((session-lock ,session) :allow-with-interrupts t)
,@body))
(defun new-session ()
(make-session :threads (list *current-thread*)
:interactive-threads (list *current-thread*)))
(defun init-job-control ()
(/show0 "Entering INIT-JOB-CONTROL")
(setf *session* (new-session))
(/show0 "Exiting INIT-JOB-CONTROL"))
(defun %delete-thread-from-session (thread session)
(with-session-lock (session)
(setf (session-threads session)
(delete thread (session-threads session))
(session-interactive-threads session)
(delete thread (session-interactive-threads session)))))
(defun call-with-new-session (fn)
(%delete-thread-from-session *current-thread* *session*)
(let ((*session* (new-session)))
(funcall fn)))
(defmacro with-new-session (args &body forms)
(declare (ignore args)) ;for extensibility
(sb!int:with-unique-names (fb-name)
`(labels ((,fb-name () ,@forms))
(call-with-new-session (function ,fb-name)))))
;;; Remove thread from its session, if it has one.
#!+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)
(setf (thread-os-thread thread) nil)
(setq *all-threads* (delete thread *all-threads*))
(when *session*
(%delete-thread-from-session thread *session*)))
#!+sb-lutex
(without-gcing
(/show0 "FREEING MUTEX LUTEX")
(with-lutex-address (lutex (mutex-lutex (thread-interruptions-lock thread)))
(%lutex-destroy lutex))))
(defun terminate-session ()
#!+sb-doc
"Kill all threads in session except for this one. Does nothing if current
thread is not the foreground thread."
;; FIXME: threads created in other threads may escape termination
(let ((to-kill
(with-session-lock (*session*)
(and (eq *current-thread*
(car (session-interactive-threads *session*)))
(session-threads *session*)))))
;; do the kill after dropping the mutex; unwind forms in dying
;; threads may want to do session things
(dolist (thread to-kill)
(unless (eq thread *current-thread*)
;; terminate the thread but don't be surprised if it has
;; exited in the meantime
(handler-case (terminate-thread thread)
(interrupt-thread-error ()))))))
;;; called from top of invoke-debugger
(defun debugger-wait-until-foreground-thread (stream)
"Returns T if thread had been running in background, NIL if it was
interactive."
(declare (ignore stream))
#!-sb-thread nil
#!+sb-thread
(prog1
(with-session-lock (*session*)
(not (member *current-thread*
(session-interactive-threads *session*))))
(get-foreground)))
(defun get-foreground ()
#!-sb-thread t
#!+sb-thread
(let ((was-foreground t))
(loop
(/show0 "Looping in GET-FOREGROUND")
(with-session-lock (*session*)
(let ((int-t (session-interactive-threads *session*)))
(when (eq (car int-t) *current-thread*)
(unless was-foreground
(format *query-io* "Resuming thread ~A~%" *current-thread*))
(return-from get-foreground t))
(setf was-foreground nil)
(unless (member *current-thread* int-t)
(setf (cdr (last int-t))
(list *current-thread*)))
(condition-wait
(session-interactive-threads-queue *session*)
(session-lock *session*)))))))
(defun release-foreground (&optional next)
#!+sb-doc
"Background this thread. If NEXT is supplied, arrange for it to
have the foreground next."
#!-sb-thread (declare (ignore next))
#!-sb-thread nil
#!+sb-thread
(with-session-lock (*session*)
(when (rest (session-interactive-threads *session*))
(setf (session-interactive-threads *session*)
(delete *current-thread* (session-interactive-threads *session*))))
(when next
(setf (session-interactive-threads *session*)
(list* next
(delete next (session-interactive-threads *session*)))))
(condition-broadcast (session-interactive-threads-queue *session*))))
(defun foreground-thread ()
(car (session-interactive-threads *session*)))
(defun make-listener-thread (tty-name)
(assert (probe-file tty-name))
(let* ((in (sb!unix:unix-open (namestring tty-name) sb!unix:o_rdwr #o666))
(out (sb!unix:unix-dup in))
(err (sb!unix:unix-dup in)))
(labels ((thread-repl ()
(sb!unix::unix-setsid)
(let* ((sb!impl::*stdin*
(make-fd-stream in :input t :buffering :line
:dual-channel-p t))
(sb!impl::*stdout*
(make-fd-stream out :output t :buffering :line
:dual-channel-p t))
(sb!impl::*stderr*
(make-fd-stream err :output t :buffering :line
:dual-channel-p t))
(sb!impl::*tty*
(make-fd-stream err :input t :output t
:buffering :line
:dual-channel-p t))
(sb!impl::*descriptor-handlers* nil))
(with-new-session ()
(unwind-protect
(sb!impl::toplevel-repl nil)
(sb!int:flush-standard-output-streams))))))
(make-thread #'thread-repl))))
;;;; the beef
(defun make-thread (function &key name)
#!+sb-doc
"Create a new thread of NAME that runs FUNCTION. When the function
returns the thread exits. The return values of FUNCTION are kept
around and can be retrieved by JOIN-THREAD."
#!-sb-thread (declare (ignore function name))
#!-sb-thread (error "Not supported in unithread builds.")
#!+sb-thread
(let* ((thread (%make-thread :name name))
(setup-sem (make-semaphore :name "Thread setup semaphore"))
(real-function (coerce function 'function))
(initial-function
(lambda ()
;; In time we'll move some of the binding presently done in C
;; here too.
;;
;; KLUDGE: Here we have a magic list of variables that are
;; not thread-safe for one reason or another. As people
;; report problems with the thread safety of certain
;; variables, (e.g. "*print-case* in multiple threads
;; broken", sbcl-devel 2006-07-14), we add a few more
;; bindings here. The Right Thing is probably some variant
;; 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))
(with-mutex ((thread-result-lock thread))
(with-all-threads-lock
(push thread *all-threads*))
(with-session-lock (*session*)
(push thread (session-threads *session*)))
(setf (thread-%alive-p thread) t)
(signal-semaphore setup-sem)
;; can't use handling-end-of-the-world, because that flushes
;; output streams, and we don't necessarily have any (or we
;; could be sharing them)
(catch 'sb!impl::toplevel-catcher
(catch 'sb!impl::%end-of-the-world
(with-simple-restart
(terminate-thread
(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)))))))
(values))))
;; 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))))
(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
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))
(cond ((car (thread-result thread))
(values-list (cdr (thread-result thread))))
(defaultp
default)
(t
(error 'join-thread-error :thread thread)))))
(defun destroy-thread (thread)
#!+sb-doc
"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))
;; 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.
(defun interrupt-thread (thread function)
#!+sb-doc
"Interrupt the live THREAD and make it run FUNCTION. A moderate
degree of care is expected for use of INTERRUPT-THREAD, due to its
nature: if you interrupt a thread that was holding important locks
then do something that turns out to need those locks, you probably
won't like the effect."
#!-sb-thread (declare (ignore thread))
#!-sb-thread
(with-interrupt-bindings
(with-interrupts (funcall function)))
#!+sb-thread
(if (eq thread *current-thread*)
(with-interrupt-bindings
(with-interrupts (funcall function)))
(let ((os-thread (thread-os-thread thread)))
(cond ((not os-thread)
(error 'interrupt-thread-error :thread thread))
(t
(with-interruptions-lock (thread)
(push function (thread-interruptions thread)))
(when (minusp (signal-interrupt-thread os-thread))
(error 'interrupt-thread-error :thread thread)))))))
(defun terminate-thread (thread)
#!+sb-doc
"Terminate the thread identified by THREAD, by causing it to run
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.")
#!+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))))
(defun sb!vm::locked-symbol-global-value-add (symbol-name delta)
(sb!vm::locked-symbol-global-value-add symbol-name delta))
;;; Stepping
(defun thread-stepping ()
(make-lisp-obj
(sap-ref-word (current-thread-sap)
(* sb!vm::thread-stepping-slot sb!vm:n-word-bytes))))
(defun (setf thread-stepping) (value)
(setf (sap-ref-word (current-thread-sap)
(* sb!vm::thread-stepping-slot sb!vm:n-word-bytes))
(get-lisp-obj-address value)))