;;; Used internally, but it would be nice to provide something
;;; like this for users as well.
-(defmacro define-structure-slot-compare-and-swap
- (name &key structure slot)
- (let* ((dd (find-defstruct-description structure t))
- (slotd (when dd (find slot (dd-slots dd) :key #'dsd-name)))
- (type (when slotd (dsd-type slotd)))
- (index (when slotd (dsd-index slotd))))
- (unless index
- (error "Slot ~S not found in ~S." slot structure))
- (unless (eq t (dsd-raw-type slotd))
- (error "Cannot define compare-and-swap on a raw slot."))
- (when (dsd-read-only slotd)
- (error "Cannot define compare-and-swap on a read-only slot."))
- `(progn
- (declaim (inline ,name))
- (defun ,name (instance old new)
- (declare (type ,structure instance)
- (type ,type old new))
- (%instance-compare-and-swap instance ,index old new)))))
-;;; Ditto
#!+sb-thread
(defmacro define-structure-slot-addressor (name &key structure slot)
(let* ((dd (find-defstruct-description structure t))
(- (* ,(+ sb!vm:instance-slots-offset index) sb!vm:n-word-bytes)
sb!vm:instance-pointer-lowtag)))))))
+(defmacro compare-and-swap (place old new &environment env)
+ "Atomically stores NEW in PLACE if OLD matches the current value of PLACE.
+Two values are considered to match if they are EQ. Returns the previous value
+of PLACE: if the returned value if EQ to OLD, the swap was carried out.
+
+PLACE must be an accessor form whose CAR is one of the following:
+
+ CAR, CDR, FIRST, REST, SYMBOL-PLIST, SYMBOL-VALUE, SVREF
+
+or the name of a DEFSTRUCT created accessor for a slot whose declared type is
+either FIXNUM or T. Results are unspecified if the slot has a declared type
+other then FIXNUM or T.
+
+EXPERIMENTAL: Interface subject to change."
+ (flet ((invalid-place ()
+ (error "Invalid first argument to COMPARE-AND-SWAP: ~S" place)))
+ (unless (consp place)
+ (invalid-place))
+ ;; FIXME: Not the nicest way to do this...
+ (destructuring-bind (op &rest args) place
+ (case op
+ ((car first)
+ `(%compare-and-swap-car (the cons ,@args) ,old ,new))
+ ((cdr rest)
+ `(%compare-and-swap-cdr (the cons ,@args) ,old ,new))
+ (symbol-plist
+ `(%compare-and-swap-symbol-plist (the symbol ,@args) ,old (the list ,new)))
+ (symbol-value
+ (destructuring-bind (name) args
+ (flet ((slow (symbol)
+ (with-unique-names (n-symbol n-old n-new)
+ `(let ((,n-symbol ,symbol)
+ (,n-old ,old)
+ (,n-new ,new))
+ (declare (symbol ,n-symbol))
+ (about-to-modify-symbol-value ,n-symbol "compare-and-swap SYMBOL-VALUE of ~S" ,n-new)
+ (%compare-and-swap-symbol-value ,n-symbol ,n-old ,n-new)))))
+ (if (sb!xc:constantp name env)
+ (let ((cname (constant-form-value name env)))
+ (if (eq :special (info :variable :kind cname))
+ ;; Since we know the symbol is a special, we can just generate
+ ;; the type check.
+ `(%compare-and-swap-symbol-value
+ ',cname ,old (the ,(info :variable :type cname) ,new))
+ (slow (list 'quote cname))))
+ (slow name)))))
+ (svref
+ (let ((vector (car args))
+ (index (cadr args)))
+ (unless (and vector index (not (cddr args)))
+ (invalid-place))
+ (with-unique-names (v)
+ `(let ((,v ,vector))
+ (declare (simple-vector ,v))
+ (%compare-and-swap-svref ,v (%check-bound ,v (length ,v) ,index) ,old ,new)))))
+ (t
+ (let ((dd (info :function :structure-accessor op)))
+ (if dd
+ (let* ((structure (dd-name dd))
+ (slotd (find op (dd-slots dd) :key #'dsd-accessor-name))
+ (index (dsd-index slotd))
+ (type (dsd-type slotd)))
+ (unless (eq t (dsd-raw-type slotd))
+ (error "Cannot use COMPARE-AND-SWAP with structure accessor for a typed slot: ~S"
+ place))
+ (when (dsd-read-only slotd)
+ (error "Cannot use COMPARE-AND-SWAP with structure accessor for a read-only slot: ~S"
+ place))
+ `(truly-the (values ,type &optional)
+ (%compare-and-swap-instance-ref (the ,structure ,@args)
+ ,index
+ (the ,type ,old) (the ,type ,new))))
+ (error "Invalid first argument to COMPARE-AND-SWAP: ~S" place))))))))
+
+(macrolet ((def (name lambda-list ref &optional set)
+ #!+compare-and-swap-vops
+ (declare (ignore ref set))
+ `(defun ,name (,@lambda-list old new)
+ #!+compare-and-swap-vops
+ (,name ,@lambda-list old new)
+ #!-compare-and-swap-vops
+ (let ((current (,ref ,@lambda-list)))
+ (when (eq current old)
+ ,(if set
+ `(,set ,@lambda-list new)
+ `(setf (,ref ,@lambda-list) new)))
+ current))))
+ (def %compare-and-swap-car (cons) car)
+ (def %compare-and-swap-cdr (cons) cdr)
+ (def %compare-and-swap-instance-ref (instance index) %instance-ref %instance-set)
+ (def %compare-and-swap-symbol-plist (symbol) symbol-plist)
+ (def %compare-and-swap-symbol-value (symbol) symbol-value)
+ (def %compare-and-swap-svref (vector index) svref))
+
+(defmacro atomic-incf (place &optional (diff 1) &environment env)
+ #!+sb-doc
+ "Atomically increments PLACE by DIFF, and returns the value of PLACE before
+the increment.
+
+The incrementation is done using word-size modular arithmetic: on 32 bit
+platforms ATOMIC-INCF of #xFFFFFFFF by one results in #x0 being stored in
+PLACE.
+
+PLACE must be an accessor form whose CAR is the name of a DEFSTRUCT accessor
+whose declared type is (UNSIGNED-BYTE 32) on 32 bit platforms,
+and (UNSIGNED-BYTE 64) on 64 bit platforms.
+
+DIFF defaults to 1, and must be a (SIGNED-BYTE 32) on 32 bit platforms,
+and (SIGNED-BYTE 64) on 64 bit platforms.
+
+EXPERIMENTAL: Interface subject to change."
+ (flet ((invalid-place ()
+ (error "Invalid first argument to ATOMIC-INCF: ~S" place)))
+ (let ((place (macroexpand place env)))
+ (unless (consp place)
+ (invalid-place))
+ (destructuring-bind (op &rest args) place
+ (when (cdr args)
+ (invalid-place))
+ (let ((dd (info :function :structure-accessor op)))
+ (if dd
+ (let* ((structure (dd-name dd))
+ (slotd (find op (dd-slots dd) :key #'dsd-accessor-name))
+ (index (dsd-index slotd))
+ (type (dsd-type slotd)))
+ (declare (ignorable index))
+ (unless (and (eq 'sb!vm:word (dsd-raw-type slotd))
+ (type= (specifier-type type) (specifier-type 'sb!vm:word)))
+ (error "ATOMIC-INCF requires a slot of type (UNSIGNED-BYTE ~S), not ~S: ~S"
+ sb!vm:n-word-bits type place))
+ (when (dsd-read-only slotd)
+ (error "Cannot use ATOMIC-INCF with structure accessor for a read-only slot: ~S"
+ place))
+ #!+(or x86 x86-64)
+ `(truly-the sb!vm:word
+ (%raw-instance-atomic-incf/word (the ,structure ,@args)
+ ,index
+ (the sb!vm:signed-word ,diff)))
+ ;; No threads outside x86 and x86-64 for now, so this is easy...
+ #!-(or x86 x86-64)
+ (with-unique-names (structure old)
+ `(sb!sys:without-interrupts
+ (let* ((,structure ,@args)
+ (,old (,op ,structure)))
+ (setf (,op ,structure) (logand #.(1- (ash 1 sb!vm:n-word-bits))
+ (+ ,old (the sb!vm:signed-word ,diff))))
+ ,old))))
+ (invalid-place)))))))
+
+(defun call-hooks (kind hooks &key (on-error :error))
+ (dolist (hook hooks)
+ (handler-case
+ (funcall hook)
+ (serious-condition (c)
+ (if (eq :warn on-error)
+ (warn "Problem running ~A hook ~S:~% ~A" kind hook c)
+ (with-simple-restart (continue "Skip this ~A hook." kind)
+ (error "Problem running ~A hook ~S:~% ~A" kind hook c)))))))