1 ;;;; the basics of the PCL wrapper cache mechanism
3 ;;;; This software is part of the SBCL system. See the README file for
6 ;;;; This software is derived from software originally released by Xerox
7 ;;;; Corporation. Copyright and release statements follow. Later modifications
8 ;;;; to the software are in the public domain and are provided with
9 ;;;; absolutely no warranty. See the COPYING and CREDITS files for more
12 ;;;; copyright information from original PCL sources:
14 ;;;; Copyright (c) 1985, 1986, 1987, 1988, 1989, 1990 Xerox Corporation.
15 ;;;; All rights reserved.
17 ;;;; Use and copying of this software and preparation of derivative works based
18 ;;;; upon this software are permitted. Any distribution of this software or
19 ;;;; derivative works must comply with all applicable United States export
22 ;;;; This software is made available AS IS, and Xerox Corporation makes no
23 ;;;; warranty about the software, its performance or its conformity to any
28 ;;; The caching algorithm implemented:
30 ;;; << put a paper here >>
32 ;;; For now, understand that as far as most of this code goes, a cache
33 ;;; has two important properties. The first is the number of wrappers
34 ;;; used as keys in each cache line. Throughout this code, this value
35 ;;; is always called NKEYS. The second is whether or not the cache
36 ;;; lines of a cache store a value. Throughout this code, this always
39 ;;; Depending on these values, there are three kinds of caches.
41 ;;; NKEYS = 1, VALUEP = NIL
43 ;;; In this kind of cache, each line is 1 word long. No cache locking
44 ;;; is needed since all read's in the cache are a single value.
45 ;;; Nevertheless line 0 (location 0) is reserved, to ensure that
46 ;;; invalid wrappers will not get a first probe hit.
48 ;;; To keep the code simpler, a cache lock count does appear in
49 ;;; location 0 of these caches, that count is incremented whenever
50 ;;; data is written to the cache. But, the actual lookup code (see
51 ;;; make-dlap) doesn't need to do locking when reading the cache.
53 ;;; NKEYS = 1, VALUEP = T
55 ;;; In this kind of cache, each line is 2 words long. Cache locking
56 ;;; must be done to ensure the synchronization of cache reads. Line 0
57 ;;; of the cache (location 0) is reserved for the cache lock count.
58 ;;; Location 1 of the cache is unused (in effect wasted).
62 ;;; In this kind of cache, the 0 word of the cache holds the lock
63 ;;; count. The 1 word of the cache is line 0. Line 0 of these caches
66 ;;; This is done because in this sort of cache, the overhead of doing
67 ;;; the cache probe is high enough that the 1+ required to offset the
68 ;;; location is not a significant cost. In addition, because of the
69 ;;; larger line sizes, the space that would be wasted by reserving
70 ;;; line 0 to hold the lock count is more significant.
74 ;;; A cache is essentially just a vector. The use of the individual
75 ;;; `words' in the vector depends on particular properties of the
76 ;;; cache as described above.
78 ;;; This defines an abstraction for caches in terms of their most
79 ;;; obvious implementation as simple vectors. But, please notice that
80 ;;; part of the implementation of this abstraction, is the function
81 ;;; lap-out-cache-ref. This means that most port-specific
82 ;;; modifications to the implementation of caches will require
83 ;;; corresponding port-specific modifications to the lap code
85 (defmacro cache-vector-ref (cache-vector location)
86 `(svref (the simple-vector ,cache-vector)
87 (sb-ext:truly-the fixnum ,location)))
89 (defmacro cache-vector-size (cache-vector)
90 `(array-dimension (the simple-vector ,cache-vector) 0))
92 (defun allocate-cache-vector (size)
93 (make-array size :adjustable nil))
95 (defmacro cache-vector-lock-count (cache-vector)
96 `(cache-vector-ref ,cache-vector 0))
98 (defun flush-cache-vector-internal (cache-vector)
99 (sb-sys:without-interrupts
100 (fill (the simple-vector cache-vector) nil)
101 (setf (cache-vector-lock-count cache-vector) 0))
104 (defmacro modify-cache (cache-vector &body body)
105 `(sb-sys:without-interrupts
106 (multiple-value-prog1
108 (let ((old-count (cache-vector-lock-count ,cache-vector)))
109 (declare (fixnum old-count))
110 (setf (cache-vector-lock-count ,cache-vector)
111 (if (= old-count most-positive-fixnum)
112 1 (the fixnum (1+ old-count))))))))
114 (deftype field-type ()
115 '(mod #.sb-kernel:layout-clos-hash-length))
117 (eval-when (:compile-toplevel :load-toplevel :execute)
118 (defun power-of-two-ceiling (x)
120 ;;(expt 2 (ceiling (log x 2)))
121 (the fixnum (ash 1 (integer-length (1- x)))))
124 (defconstant +nkeys-limit+ 256)
126 (defstruct (cache (:constructor make-cache ())
127 (:copier copy-cache-internal))
129 (nkeys 1 :type (integer 1 #.+nkeys-limit+))
130 (valuep nil :type (member nil t))
131 (nlines 0 :type fixnum)
132 (field 0 :type field-type)
133 (limit-fn #'default-limit-fn :type function)
134 (mask 0 :type fixnum)
135 (size 0 :type fixnum)
136 (line-size 1 :type (integer 1 #.(power-of-two-ceiling (1+ +nkeys-limit+))))
137 (max-location 0 :type fixnum)
138 (vector #() :type simple-vector)
139 (overflow nil :type list))
141 #-sb-fluid (declaim (sb-ext:freeze-type cache))
143 (defmacro cache-lock-count (cache)
144 `(cache-vector-lock-count (cache-vector ,cache)))
146 ;;; some facilities for allocation and freeing caches as they are needed
148 ;;; This is done on the assumption that a better port of PCL will
149 ;;; arrange to cons these all in the same static area. Given that, the
150 ;;; fact that PCL tries to reuse them should be a win.
152 (defvar *free-cache-vectors* (make-hash-table :size 16 :test 'eql))
154 ;;; Return a cache that has had FLUSH-CACHE-VECTOR-INTERNAL called on
155 ;;; it. This returns a cache of exactly the size requested, it won't
156 ;;; ever return a larger cache.
157 (defun get-cache-vector (size)
158 (let ((entry (gethash size *free-cache-vectors*)))
159 (sb-sys:without-interrupts
161 (setf (gethash size *free-cache-vectors*) (cons 0 nil))
162 (get-cache-vector size))
165 (flush-cache-vector-internal (allocate-cache-vector size)))
167 (let ((cache (cdr entry)))
168 (setf (cdr entry) (cache-vector-ref cache 0))
169 (flush-cache-vector-internal cache)))))))
171 (defun free-cache-vector (cache-vector)
172 (let ((entry (gethash (cache-vector-size cache-vector) *free-cache-vectors*)))
173 (sb-sys:without-interrupts
176 "attempt to free a cache-vector not allocated by GET-CACHE-VECTOR")
177 (let ((thread (cdr entry)))
178 (loop (unless thread (return))
179 (when (eq thread cache-vector)
180 (error "freeing a cache twice"))
181 (setq thread (cache-vector-ref thread 0)))
182 (flush-cache-vector-internal cache-vector) ; to help the GC
183 (setf (cache-vector-ref cache-vector 0) (cdr entry))
184 (setf (cdr entry) cache-vector)
187 ;;; This is just for debugging and analysis. It shows the state of the
188 ;;; free cache resource.
190 (defun show-free-cache-vectors ()
192 (maphash #'(lambda (s e) (push (list s e) elements)) *free-cache-vectors*)
193 (setq elements (sort elements #'< :key #'car))
195 (let* ((size (car e))
197 (allocated (car entry))
200 (loop (when (null head) (return t))
201 (setq head (cache-vector-ref head 0))
204 "~&There ~4D are caches of size ~4D. (~D free ~3D%)"
208 (floor (* 100 (/ free (float allocated)))))))))
210 ;;;; wrapper cache numbers
212 ;;; The constant WRAPPER-CACHE-NUMBER-ADDS-OK controls the number of
213 ;;; non-zero bits wrapper cache numbers will have.
215 ;;; The value of this constant is the number of wrapper cache numbers
216 ;;; which can be added and still be certain the result will be a
217 ;;; fixnum. This is used by all the code that computes primary cache
218 ;;; locations from multiple wrappers.
220 ;;; The value of this constant is used to derive the next two which
221 ;;; are the forms of this constant which it is more convenient for the
222 ;;; runtime code to use.
223 (defconstant wrapper-cache-number-length
224 (integer-length sb-kernel:layout-clos-hash-max))
225 (defconstant wrapper-cache-number-mask sb-kernel:layout-clos-hash-max)
226 (defconstant wrapper-cache-number-adds-ok
227 (truncate most-positive-fixnum sb-kernel:layout-clos-hash-max))
229 ;;;; wrappers themselves
231 ;;; This caching algorithm requires that wrappers have more than one
232 ;;; wrapper cache number. You should think of these multiple numbers
233 ;;; as being in columns. That is, for a given cache, the same column
234 ;;; of wrapper cache numbers will be used.
236 ;;; If at some point the cache distribution of a cache gets bad, the
237 ;;; cache can be rehashed by switching to a different column.
239 ;;; The columns are referred to by field number which is that number
240 ;;; which, when used as a second argument to wrapper-ref, will return
241 ;;; that column of wrapper cache number.
243 ;;; This code is written to allow flexibility as to how many wrapper
244 ;;; cache numbers will be in each wrapper, and where they will be
245 ;;; located. It is also set up to allow port specific modifications to
246 ;;; `pack' the wrapper cache numbers on machines where the addressing
247 ;;; modes make that a good idea.
249 ;;; In SBCL, as in CMU CL, we want to do type checking as early as
250 ;;; possible; structures help this. The structures are hard-wired to
251 ;;; have a fixed number of cache hash values, and that number must
252 ;;; correspond to the number of cache lines we use.
253 (defconstant wrapper-cache-number-vector-length
254 sb-kernel:layout-clos-hash-length)
256 (unless (boundp '*the-class-t*)
257 (setq *the-class-t* nil))
259 (defmacro wrapper-class (wrapper)
260 `(sb-kernel:class-pcl-class (sb-kernel:layout-class ,wrapper)))
261 (defmacro wrapper-no-of-instance-slots (wrapper)
262 `(sb-kernel:layout-length ,wrapper))
264 ;;; WRAPPER-STATE returns T (not generalized boolean, but T exactly)
265 ;;; iff the wrapper is valid. Any other return value denotes some
266 ;;; invalid state. Special conventions have been set up for certain
267 ;;; invalid states, e.g. obsoleteness or flushedness, but I (WHN
268 ;;; 19991204) haven't been motivated to reverse engineer them from the
269 ;;; code and document them here.
271 ;;; FIXME: This is awkward and unmnemonic. There is a function
272 ;;; (INVALID-WRAPPER-P) to test this return result abstractly for
273 ;;; invalidness but it's not called consistently; the functions that
274 ;;; need to know whether a wrapper is invalid often test (EQ
275 ;;; (WRAPPER-STATE X) T), ick. It would be good to use the abstract
276 ;;; test instead. It would probably be even better to switch the sense
277 ;;; of the WRAPPER-STATE function, renaming it to WRAPPER-INVALID and
278 ;;; making it synonymous with LAYOUT-INVALID. Then the
279 ;;; INVALID-WRAPPER-P function would become trivial and would go away
280 ;;; (replaced with WRAPPER-INVALID), since all the various invalid
281 ;;; wrapper states would become generalized boolean "true" values. --
283 #-sb-fluid (declaim (inline wrapper-state (setf wrapper-state)))
284 (defun wrapper-state (wrapper)
285 (let ((invalid (sb-kernel:layout-invalid wrapper)))
286 (cond ((null invalid)
289 ;; some non-PCL object. INVALID is probably :INVALID. We
290 ;; should arguably compute the new wrapper here instead of
291 ;; returning NIL, but we don't bother, since
292 ;; OBSOLETE-INSTANCE-TRAP can't use it.
296 (defun (setf wrapper-state) (new-value wrapper)
297 (setf (sb-kernel:layout-invalid wrapper)
302 (defmacro wrapper-instance-slots-layout (wrapper)
303 `(%wrapper-instance-slots-layout ,wrapper))
304 (defmacro wrapper-class-slots (wrapper)
305 `(%wrapper-class-slots ,wrapper))
306 (defmacro wrapper-cache-number-vector (x) x)
308 ;;; This is called in BRAID when we are making wrappers for classes
309 ;;; whose slots are not initialized yet, and which may be built-in
310 ;;; classes. We pass in the class name in addition to the class.
311 (defun boot-make-wrapper (length name &optional class)
312 (let ((found (cl:find-class name nil)))
315 (unless (sb-kernel:class-pcl-class found)
316 (setf (sb-kernel:class-pcl-class found) class))
317 (aver (eq (sb-kernel:class-pcl-class found) class))
318 (let ((layout (sb-kernel:class-layout found)))
322 (make-wrapper-internal
324 :class (sb-kernel:make-standard-class :name name :pcl-class class))))))
326 ;;; The following variable may be set to a STANDARD-CLASS that has
327 ;;; already been created by the lisp code and which is to be redefined
328 ;;; by PCL. This allows STANDARD-CLASSes to be defined and used for
329 ;;; type testing and dispatch before PCL is loaded.
330 (defvar *pcl-class-boot* nil)
332 ;;; In SBCL, as in CMU CL, the layouts (a.k.a wrappers) for built-in
333 ;;; and structure classes already exist when PCL is initialized, so we
334 ;;; don't necessarily always make a wrapper. Also, we help maintain
335 ;;; the mapping between CL:CLASS and PCL::CLASS objects.
336 (defun make-wrapper (length class)
338 ((typep class 'std-class)
339 (make-wrapper-internal
342 (let ((owrap (class-wrapper class)))
344 (sb-kernel:layout-class owrap))
345 ((*subtypep (class-of class)
346 *the-class-standard-class*)
347 (cond ((and *pcl-class-boot*
348 (eq (slot-value class 'name) *pcl-class-boot*))
349 (let ((found (cl:find-class (slot-value class 'name))))
350 (unless (sb-kernel:class-pcl-class found)
351 (setf (sb-kernel:class-pcl-class found) class))
352 (aver (eq (sb-kernel:class-pcl-class found) class))
355 (sb-kernel:make-standard-class :pcl-class class))))
357 (sb-kernel:make-random-pcl-class :pcl-class class))))))
359 (let* ((found (cl:find-class (slot-value class 'name)))
360 (layout (sb-kernel:class-layout found)))
361 (unless (sb-kernel:class-pcl-class found)
362 (setf (sb-kernel:class-pcl-class found) class))
363 (aver (eq (sb-kernel:class-pcl-class found) class))
367 ;;; FIXME: The immediately following macros could become inline functions.
369 (defmacro first-wrapper-cache-number-index ()
372 (defmacro next-wrapper-cache-number-index (field-number)
373 `(and (< ,field-number #.(1- wrapper-cache-number-vector-length))
376 (defmacro cache-number-vector-ref (cnv n)
377 `(wrapper-cache-number-vector-ref ,cnv ,n))
379 (defmacro wrapper-cache-number-vector-ref (wrapper n)
380 `(sb-kernel:layout-clos-hash ,wrapper ,n))
382 (defmacro class-no-of-instance-slots (class)
383 `(wrapper-no-of-instance-slots (class-wrapper ,class)))
385 (defmacro wrapper-class* (wrapper)
386 `(let ((wrapper ,wrapper))
387 (or (wrapper-class wrapper)
388 (find-structure-class
389 (cl:class-name (sb-kernel:layout-class wrapper))))))
391 ;;; The wrapper cache machinery provides general mechanism for
392 ;;; trapping on the next access to any instance of a given class. This
393 ;;; mechanism is used to implement the updating of instances when the
394 ;;; class is redefined (MAKE-INSTANCES-OBSOLETE). The same mechanism
395 ;;; is also used to update generic function caches when there is a
396 ;;; change to the superclasses of a class.
398 ;;; Basically, a given wrapper can be valid or invalid. If it is
399 ;;; invalid, it means that any attempt to do a wrapper cache lookup
400 ;;; using the wrapper should trap. Also, methods on
401 ;;; SLOT-VALUE-USING-CLASS check the wrapper validity as well. This is
402 ;;; done by calling CHECK-WRAPPER-VALIDITY.
404 ;;; FIXME: could become inline function
405 (defmacro invalid-wrapper-p (wrapper)
406 `(neq (wrapper-state ,wrapper) t))
408 (defvar *previous-nwrappers* (make-hash-table))
410 (defun invalidate-wrapper (owrapper state nwrapper)
413 (let ((new-previous ()))
414 ;; First off, a previous call to INVALIDATE-WRAPPER may have
415 ;; recorded OWRAPPER as an NWRAPPER to update to. Since
416 ;; OWRAPPER is about to be invalid, it no longer makes sense to
419 ;; We go back and change the previously invalidated wrappers so
420 ;; that they will now update directly to NWRAPPER. This
421 ;; corresponds to a kind of transitivity of wrapper updates.
422 (dolist (previous (gethash owrapper *previous-nwrappers*))
423 (when (eq state ':obsolete)
424 (setf (car previous) ':obsolete))
425 (setf (cadr previous) nwrapper)
426 (push previous new-previous))
428 (let ((ocnv (wrapper-cache-number-vector owrapper)))
429 (dotimes (i sb-kernel:layout-clos-hash-length)
430 (setf (cache-number-vector-ref ocnv i) 0)))
431 (push (setf (wrapper-state owrapper) (list state nwrapper))
434 (setf (gethash owrapper *previous-nwrappers*) ()
435 (gethash nwrapper *previous-nwrappers*) new-previous)))))
437 (defun check-wrapper-validity (instance)
438 (let* ((owrapper (wrapper-of instance))
439 (state (wrapper-state owrapper)))
445 (flush-cache-trap owrapper (cadr state) instance))
447 (obsolete-instance-trap owrapper (cadr state) instance)))))
448 ;; This little bit of error checking is superfluous. It only
449 ;; checks to see whether the person who implemented the trap
450 ;; handling screwed up. Since that person is hacking
451 ;; internal PCL code, and is not a user, this should be
452 ;; needless. Also, since this directly slows down instance
453 ;; update and generic function cache refilling, feel free to
454 ;; take it out sometime soon.
456 ;; FIXME: We probably need to add a #+SB-PARANOID feature to
457 ;; make stuff like this optional. Until then, it stays in.
458 (cond ((neq nwrapper (wrapper-of instance))
459 (error "wrapper returned from trap not wrapper of instance"))
460 ((invalid-wrapper-p nwrapper)
461 (error "wrapper returned from trap invalid")))
464 (defmacro check-wrapper-validity1 (object)
465 (let ((owrapper (gensym)))
466 `(let ((,owrapper (sb-kernel:layout-of object)))
467 (if (sb-kernel:layout-invalid ,owrapper)
468 (check-wrapper-validity ,object)
471 (defvar *free-caches* nil)
473 (defun get-cache (nkeys valuep limit-fn nlines)
474 (let ((cache (or (sb-sys:without-interrupts (pop *free-caches*))
476 (declare (type cache cache))
477 (multiple-value-bind (cache-mask actual-size line-size nlines)
478 (compute-cache-parameters nkeys valuep nlines)
479 (setf (cache-nkeys cache) nkeys
480 (cache-valuep cache) valuep
481 (cache-nlines cache) nlines
482 (cache-field cache) (first-wrapper-cache-number-index)
483 (cache-limit-fn cache) limit-fn
484 (cache-mask cache) cache-mask
485 (cache-size cache) actual-size
486 (cache-line-size cache) line-size
487 (cache-max-location cache) (let ((line (1- nlines)))
490 (1+ (* line line-size))))
491 (cache-vector cache) (get-cache-vector actual-size)
492 (cache-overflow cache) nil)
495 (defun get-cache-from-cache (old-cache new-nlines
496 &optional (new-field (first-wrapper-cache-number-index)))
497 (let ((nkeys (cache-nkeys old-cache))
498 (valuep (cache-valuep old-cache))
499 (cache (or (sb-sys:without-interrupts (pop *free-caches*))
501 (declare (type cache cache))
502 (multiple-value-bind (cache-mask actual-size line-size nlines)
503 (if (= new-nlines (cache-nlines old-cache))
504 (values (cache-mask old-cache) (cache-size old-cache)
505 (cache-line-size old-cache) (cache-nlines old-cache))
506 (compute-cache-parameters nkeys valuep new-nlines))
507 (setf (cache-owner cache) (cache-owner old-cache)
508 (cache-nkeys cache) nkeys
509 (cache-valuep cache) valuep
510 (cache-nlines cache) nlines
511 (cache-field cache) new-field
512 (cache-limit-fn cache) (cache-limit-fn old-cache)
513 (cache-mask cache) cache-mask
514 (cache-size cache) actual-size
515 (cache-line-size cache) line-size
516 (cache-max-location cache) (let ((line (1- nlines)))
519 (1+ (* line line-size))))
520 (cache-vector cache) (get-cache-vector actual-size)
521 (cache-overflow cache) nil)
524 (defun copy-cache (old-cache)
525 (let* ((new-cache (copy-cache-internal old-cache))
526 (size (cache-size old-cache))
527 (old-vector (cache-vector old-cache))
528 (new-vector (get-cache-vector size)))
529 (declare (simple-vector old-vector new-vector))
530 (dotimes-fixnum (i size)
531 (setf (svref new-vector i) (svref old-vector i)))
532 (setf (cache-vector new-cache) new-vector)
535 (defun free-cache (cache)
536 (free-cache-vector (cache-vector cache))
537 (setf (cache-vector cache) #())
538 (setf (cache-owner cache) nil)
539 (push cache *free-caches*)
542 (defun compute-line-size (x)
543 (power-of-two-ceiling x))
545 (defun compute-cache-parameters (nkeys valuep nlines-or-cache-vector)
546 ;;(declare (values cache-mask actual-size line-size nlines))
547 (declare (fixnum nkeys))
549 (let* ((line-size (if valuep 2 1))
550 (cache-size (if (typep nlines-or-cache-vector 'fixnum)
554 (power-of-two-ceiling
555 nlines-or-cache-vector))))
556 (cache-vector-size nlines-or-cache-vector))))
557 (declare (fixnum line-size cache-size))
558 (values (logxor (the fixnum (1- cache-size)) (the fixnum (1- line-size)))
561 (the (values fixnum t) (floor cache-size line-size))))
562 (let* ((line-size (power-of-two-ceiling (if valuep (1+ nkeys) nkeys)))
563 (cache-size (if (typep nlines-or-cache-vector 'fixnum)
567 (power-of-two-ceiling
568 nlines-or-cache-vector))))
569 (1- (cache-vector-size nlines-or-cache-vector)))))
570 (declare (fixnum line-size cache-size))
571 (values (logxor (the fixnum (1- cache-size)) (the fixnum (1- line-size)))
572 (the fixnum (1+ cache-size))
574 (the (values fixnum t) (floor cache-size line-size))))))
576 ;;; the various implementations of computing a primary cache location from
577 ;;; wrappers. Because some implementations of this must run fast there are
578 ;;; several implementations of the same algorithm.
580 ;;; The algorithm is:
582 ;;; SUM over the wrapper cache numbers,
583 ;;; ENSURING that the result is a fixnum
584 ;;; MASK the result against the mask argument.
586 ;;; The basic functional version. This is used by the cache miss code to
587 ;;; compute the primary location of an entry.
588 (defun compute-primary-cache-location (field mask wrappers)
590 (declare (type field-type field) (fixnum mask))
591 (if (not (listp wrappers))
593 (the fixnum (wrapper-cache-number-vector-ref wrappers field)))
594 (let ((location 0) (i 0))
595 (declare (fixnum location i))
596 (dolist (wrapper wrappers)
597 ;; First add the cache number of this wrapper to location.
598 (let ((wrapper-cache-number (wrapper-cache-number-vector-ref wrapper
600 (declare (fixnum wrapper-cache-number))
601 (if (zerop wrapper-cache-number)
602 (return-from compute-primary-cache-location 0)
604 (the fixnum (+ location wrapper-cache-number)))))
605 ;; Then, if we are working with lots of wrappers, deal with
606 ;; the wrapper-cache-number-mask stuff.
607 (when (and (not (zerop i))
608 (zerop (mod i wrapper-cache-number-adds-ok)))
610 (logand location wrapper-cache-number-mask)))
612 (the fixnum (1+ (logand mask location))))))
614 ;;; This version is called on a cache line. It fetches the wrappers
615 ;;; from the cache line and determines the primary location. Various
616 ;;; parts of the cache filling code call this to determine whether it
617 ;;; is appropriate to displace a given cache entry.
619 ;;; If this comes across a wrapper whose CACHE-NO is 0, it returns the
620 ;;; symbol invalid to suggest to its caller that it would be provident
621 ;;; to blow away the cache line in question.
622 (defun compute-primary-cache-location-from-location (to-cache
625 (from-cache to-cache))
626 (declare (type cache to-cache from-cache) (fixnum from-location))
628 (cache-vector (cache-vector from-cache))
629 (field (cache-field to-cache))
630 (mask (cache-mask to-cache))
631 (nkeys (cache-nkeys to-cache)))
632 (declare (type field-type field) (fixnum result mask nkeys)
633 (simple-vector cache-vector))
634 (dotimes-fixnum (i nkeys)
635 (let* ((wrapper (cache-vector-ref cache-vector (+ i from-location)))
636 (wcn (wrapper-cache-number-vector-ref wrapper field)))
637 (declare (fixnum wcn))
638 (setq result (+ result wcn)))
639 (when (and (not (zerop i))
640 (zerop (mod i wrapper-cache-number-adds-ok)))
641 (setq result (logand result wrapper-cache-number-mask))))
644 (the fixnum (1+ (logand mask result))))))
646 ;;; NIL means nothing so far, no actual arg info has NILs
648 ;;; CLASS seen all sorts of metaclasses
649 ;;; (specifically, more than one of the next 4 values)
650 ;;; T means everything so far is the class T
651 ;;; STANDARD-CLASS seen only standard classes
652 ;;; BUILT-IN-CLASS seen only built in classes
653 ;;; STRUCTURE-CLASS seen only structure classes
654 (defun raise-metatype (metatype new-specializer)
655 (let ((slot (find-class 'slot-class))
656 (std (find-class 'std-class))
657 (standard (find-class 'standard-class))
658 (fsc (find-class 'funcallable-standard-class))
659 (structure (find-class 'structure-class))
660 (built-in (find-class 'built-in-class)))
661 (flet ((specializer->metatype (x)
662 (let ((meta-specializer
663 (if (eq *boot-state* 'complete)
664 (class-of (specializer-class x))
666 (cond ((eq x *the-class-t*) t)
667 ((*subtypep meta-specializer std)
669 ((*subtypep meta-specializer standard)
671 ((*subtypep meta-specializer fsc)
673 ((*subtypep meta-specializer structure)
675 ((*subtypep meta-specializer built-in)
677 ((*subtypep meta-specializer slot)
679 (t (error "PCL cannot handle the specializer ~S (meta-specializer ~S)."
681 meta-specializer))))))
682 ;; We implement the following table. The notation is
683 ;; that X and Y are distinct meta specializer names.
685 ;; NIL <anything> ===> <anything>
688 (let ((new-metatype (specializer->metatype new-specializer)))
689 (cond ((eq new-metatype 'slot-instance) 'class)
690 ((null metatype) new-metatype)
691 ((eq metatype new-metatype) new-metatype)
694 (defmacro with-dfun-wrappers ((args metatypes)
695 (dfun-wrappers invalid-wrapper-p
696 &optional wrappers classes types)
697 invalid-arguments-form
699 `(let* ((args-tail ,args) (,invalid-wrapper-p nil) (invalid-arguments-p nil)
700 (,dfun-wrappers nil) (dfun-wrappers-tail nil)
702 `((wrappers-rev nil) (types-rev nil) (classes-rev nil))))
703 (dolist (mt ,metatypes)
705 (setq invalid-arguments-p t)
707 (let* ((arg (pop args-tail))
710 `((class *the-class-t*)
713 (setq wrapper (wrapper-of arg))
714 (when (invalid-wrapper-p wrapper)
715 (setq ,invalid-wrapper-p t)
716 (setq wrapper (check-wrapper-validity arg)))
717 (cond ((null ,dfun-wrappers)
718 (setq ,dfun-wrappers wrapper))
719 ((not (consp ,dfun-wrappers))
720 (setq dfun-wrappers-tail (list wrapper))
721 (setq ,dfun-wrappers (cons ,dfun-wrappers dfun-wrappers-tail)))
723 (let ((new-dfun-wrappers-tail (list wrapper)))
724 (setf (cdr dfun-wrappers-tail) new-dfun-wrappers-tail)
725 (setf dfun-wrappers-tail new-dfun-wrappers-tail))))
727 `((setq class (wrapper-class* wrapper))
728 (setq type `(class-eq ,class)))))
730 `((push wrapper wrappers-rev)
731 (push class classes-rev)
732 (push type types-rev)))))
733 (if invalid-arguments-p
734 ,invalid-arguments-form
735 (let* (,@(when wrappers
736 `((,wrappers (nreverse wrappers-rev))
737 (,classes (nreverse classes-rev))
738 (,types (mapcar #'(lambda (class)
743 ;;;; some support stuff for getting a hold of symbols that we need when
744 ;;;; building the discriminator codes. It's OK for these to be interned
745 ;;;; symbols because we don't capture any user code in the scope in which
746 ;;;; these symbols are bound.
748 (defvar *dfun-arg-symbols* '(.ARG0. .ARG1. .ARG2. .ARG3.))
750 (defun dfun-arg-symbol (arg-number)
751 (or (nth arg-number (the list *dfun-arg-symbols*))
752 (intern (format nil ".ARG~A." arg-number) *pcl-package*)))
754 (defvar *slot-vector-symbols* '(.SLOTS0. .SLOTS1. .SLOTS2. .SLOTS3.))
756 (defun slot-vector-symbol (arg-number)
757 (or (nth arg-number (the list *slot-vector-symbols*))
758 (intern (format nil ".SLOTS~A." arg-number) *pcl-package*)))
760 (defun make-dfun-lambda-list (metatypes applyp)
761 (gathering1 (collecting)
762 (iterate ((i (interval :from 0))
763 (s (list-elements metatypes)))
765 (gather1 (dfun-arg-symbol i)))
768 (gather1 '.dfun-rest-arg.))))
770 (defun make-dlap-lambda-list (metatypes applyp)
771 (gathering1 (collecting)
772 (iterate ((i (interval :from 0))
773 (s (list-elements metatypes)))
775 (gather1 (dfun-arg-symbol i)))
779 (defun make-emf-call (metatypes applyp fn-variable &optional emf-type)
781 (gathering1 (collecting)
782 (iterate ((i (interval :from 0))
783 (s (list-elements metatypes)))
785 (gather1 (dfun-arg-symbol i))))))
786 `(,(if (eq emf-type 'fast-method-call)
787 'invoke-effective-method-function-fast
788 'invoke-effective-method-function)
789 ,fn-variable ,applyp ,@required ,@(when applyp `(.dfun-rest-arg.)))))
791 (defun make-dfun-call (metatypes applyp fn-variable)
793 (gathering1 (collecting)
794 (iterate ((i (interval :from 0))
795 (s (list-elements metatypes)))
797 (gather1 (dfun-arg-symbol i))))))
799 `(function-apply ,fn-variable ,@required .dfun-rest-arg.)
800 `(function-funcall ,fn-variable ,@required))))
802 (defun make-dfun-arg-list (metatypes applyp)
804 (gathering1 (collecting)
805 (iterate ((i (interval :from 0))
806 (s (list-elements metatypes)))
808 (gather1 (dfun-arg-symbol i))))))
810 `(list* ,@required .dfun-rest-arg.)
811 `(list ,@required))))
813 (defun make-fast-method-call-lambda-list (metatypes applyp)
814 (gathering1 (collecting)
816 (gather1 '.next-method-call.)
817 (iterate ((i (interval :from 0))
818 (s (list-elements metatypes)))
820 (gather1 (dfun-arg-symbol i)))
822 (gather1 '.dfun-rest-arg.))))
824 ;;;; a comment from some PCL implementor:
825 ;;;; Its too bad Common Lisp compilers freak out when you have a
826 ;;;; DEFUN with a lot of LABELS in it. If I could do that I could
827 ;;;; make this code much easier to read and work with.
829 ;;;; In the absence of that, the following little macro makes the
830 ;;;; code that follows a little bit more reasonable. I would like to
831 ;;;; add that having to practically write my own compiler in order to
832 ;;;; get just this simple thing is something of a drag.
834 ;;;; KLUDGE: Maybe we could actually implement this as LABELS now,
835 ;;;; since AFAIK CMU CL doesn't freak out when you have a DEFUN with a
836 ;;;; lot of LABELS in it (and if it does we can fix it instead of
837 ;;;; working around it). -- WHN 19991204
839 (eval-when (:compile-toplevel :load-toplevel :execute)
843 ;;; FIXME: should be undefined after bootstrapping
844 (defparameter *local-cache-functions*
846 (nkeys () (cache-nkeys .cache.))
847 (line-size () (cache-line-size .cache.))
848 (vector () (cache-vector .cache.))
849 (valuep () (cache-valuep .cache.))
850 (nlines () (cache-nlines .cache.))
851 (max-location () (cache-max-location .cache.))
852 (limit-fn () (cache-limit-fn .cache.))
853 (size () (cache-size .cache.))
854 (mask () (cache-mask .cache.))
855 (field () (cache-field .cache.))
856 (overflow () (cache-overflow .cache.))
858 ;; Return T IFF this cache location is reserved. The only time
859 ;; this is true is for line number 0 of an nkeys=1 cache.
860 (line-reserved-p (line)
861 (declare (fixnum line))
864 (location-reserved-p (location)
865 (declare (fixnum location))
868 ;; Given a line number, return the cache location. This is the
869 ;; value that is the second argument to cache-vector-ref. Basically,
870 ;; this deals with the offset of nkeys>1 caches and multiplies
872 (line-location (line)
873 (declare (fixnum line))
874 (when (line-reserved-p line)
875 (error "Line is reserved."))
877 (the fixnum (* line (line-size)))
878 (the fixnum (1+ (the fixnum (* line (line-size)))))))
880 ;; Given a cache location, return the line. This is the inverse
882 (location-line (location)
883 (declare (fixnum location))
885 (floor location (line-size))
886 (floor (the fixnum (1- location)) (line-size))))
888 ;; Given a line number, return the wrappers stored at that line.
889 ;; As usual, if nkeys=1, this returns a single value. Only when
890 ;; nkeys>1 does it return a list. An error is signalled if the
892 (line-wrappers (line)
893 (declare (fixnum line))
894 (when (line-reserved-p line) (error "Line is reserved."))
895 (location-wrappers (line-location line)))
896 (location-wrappers (location) ; avoid multiplies caused by line-location
897 (declare (fixnum location))
899 (cache-vector-ref (vector) location)
900 (let ((list (make-list (nkeys)))
902 (declare (simple-vector vector))
903 (dotimes-fixnum (i (nkeys) list)
904 (setf (nth i list) (cache-vector-ref vector (+ location i)))))))
906 ;; Given a line number, return true IFF the line's
907 ;; wrappers are the same as wrappers.
908 (line-matches-wrappers-p (line wrappers)
909 (declare (fixnum line))
910 (and (not (line-reserved-p line))
911 (location-matches-wrappers-p (line-location line) wrappers)))
912 (location-matches-wrappers-p (loc wrappers) ; must not be reserved
913 (declare (fixnum loc))
914 (let ((cache-vector (vector)))
915 (declare (simple-vector cache-vector))
917 (eq wrappers (cache-vector-ref cache-vector loc))
918 (dotimes-fixnum (i (nkeys) t)
919 (unless (eq (pop wrappers)
920 (cache-vector-ref cache-vector (+ loc i)))
923 ;; Given a line number, return the value stored at that line.
924 ;; If valuep is NIL, this returns NIL. As with line-wrappers,
925 ;; an error is signalled if the line is reserved.
927 (declare (fixnum line))
928 (when (line-reserved-p line) (error "Line is reserved."))
929 (location-value (line-location line)))
930 (location-value (loc)
931 (declare (fixnum loc))
933 (cache-vector-ref (vector) (+ loc (nkeys)))))
935 ;; Given a line number, return true iff that line has data in
936 ;; it. The state of the wrappers stored in the line is not
937 ;; checked. An error is signalled if line is reserved.
939 (when (line-reserved-p line) (error "Line is reserved."))
940 (not (null (cache-vector-ref (vector) (line-location line)))))
942 ;; Given a line number, return true iff the line is full and
943 ;; there are no invalid wrappers in the line, and the line's
944 ;; wrappers are different from wrappers.
945 ;; An error is signalled if the line is reserved.
946 (line-valid-p (line wrappers)
947 (declare (fixnum line))
948 (when (line-reserved-p line) (error "Line is reserved."))
949 (location-valid-p (line-location line) wrappers))
950 (location-valid-p (loc wrappers)
951 (declare (fixnum loc))
952 (let ((cache-vector (vector))
953 (wrappers-mismatch-p (null wrappers)))
954 (declare (simple-vector cache-vector))
955 (dotimes-fixnum (i (nkeys) wrappers-mismatch-p)
956 (let ((wrapper (cache-vector-ref cache-vector (+ loc i))))
957 (when (or (null wrapper)
958 (invalid-wrapper-p wrapper))
960 (unless (and wrappers
962 (if (consp wrappers) (pop wrappers) wrappers)))
963 (setq wrappers-mismatch-p t))))))
965 ;; how many unreserved lines separate line-1 and line-2
966 (line-separation (line-1 line-2)
967 (declare (fixnum line-1 line-2))
968 (let ((diff (the fixnum (- line-2 line-1))))
969 (declare (fixnum diff))
971 (setq diff (+ diff (nlines)))
972 (when (line-reserved-p 0)
973 (setq diff (1- diff))))
976 ;; Given a cache line, get the next cache line. This will not
977 ;; return a reserved line.
979 (declare (fixnum line))
980 (if (= line (the fixnum (1- (nlines))))
981 (if (line-reserved-p 0) 1 0)
982 (the fixnum (1+ line))))
984 (declare (fixnum loc))
985 (if (= loc (max-location))
989 (the fixnum (+ loc (line-size)))))
991 ;; Given a line which has a valid entry in it, this will return
992 ;; the primary cache line of the wrappers in that line. We just
993 ;; call COMPUTE-PRIMARY-CACHE-LOCATION-FROM-LOCATION, this is an
994 ;; easier packaging up of the call to it.
996 (declare (fixnum line))
997 (location-line (line-primary-location line)))
998 (line-primary-location (line)
999 (declare (fixnum line))
1000 (compute-primary-cache-location-from-location
1001 (cache) (line-location line)))))
1003 (defmacro with-local-cache-functions ((cache) &body body)
1004 `(let ((.cache. ,cache))
1005 (declare (type cache .cache.))
1006 (macrolet ,(mapcar #'(lambda (fn)
1007 `(,(car fn) ,(cadr fn)
1008 `(let (,,@(mapcar #'(lambda (var)
1012 *local-cache-functions*)
1017 ;;; Here is where we actually fill, recache and expand caches.
1019 ;;; The functions FILL-CACHE and PROBE-CACHE are the ONLY external
1020 ;;; entrypoints into this code.
1022 ;;; FILL-CACHE returns 1 value: a new cache
1024 ;;; a wrapper field number
1027 ;;; an absolute cache size (the size of the actual vector)
1028 ;;; It tries to re-adjust the cache every time it makes a new fill.
1029 ;;; The intuition here is that we want uniformity in the number of
1030 ;;; probes needed to find an entry. Furthermore, adjusting has the
1031 ;;; nice property of throwing out any entries that are invalid.
1032 (defvar *cache-expand-threshold* 1.25)
1034 (defun fill-cache (cache wrappers value &optional free-cache-p)
1036 ;; FILL-CACHE won't return if WRAPPERS is nil, might as well check..
1038 (error "fill-cache: WRAPPERS arg is NIL!"))
1040 (or (fill-cache-p nil cache wrappers value)
1041 (and (< (ceiling (* (cache-count cache) 1.25))
1042 (if (= (cache-nkeys cache) 1)
1043 (1- (cache-nlines cache))
1044 (cache-nlines cache)))
1045 (adjust-cache cache wrappers value free-cache-p))
1046 (expand-cache cache wrappers value free-cache-p)))
1048 (defvar *check-cache-p* nil)
1050 (defmacro maybe-check-cache (cache)
1052 (when *check-cache-p*
1053 (check-cache ,cache))
1056 (defun check-cache (cache)
1057 (with-local-cache-functions (cache)
1058 (let ((location (if (= (nkeys) 1) 0 1))
1059 (limit (funcall (limit-fn) (nlines))))
1060 (dotimes-fixnum (i (nlines) cache)
1061 (when (and (not (location-reserved-p location))
1063 (let* ((home-loc (compute-primary-cache-location-from-location
1065 (home (location-line (if (location-reserved-p home-loc)
1066 (next-location home-loc)
1068 (sep (when home (line-separation home i))))
1069 (when (and sep (> sep limit))
1070 (error "bad cache ~S ~@
1071 value at location ~D: ~D lines from its home. The limit is ~D."
1072 cache location sep limit))))
1073 (setq location (next-location location))))))
1075 (defun probe-cache (cache wrappers &optional default limit-fn)
1076 ;;(declare (values value))
1078 ;; FIXME: This and another earlier test on a WRAPPERS arg can
1079 ;; be compact assertoids.
1080 (error "WRAPPERS arg is NIL!"))
1081 (with-local-cache-functions (cache)
1082 (let* ((location (compute-primary-cache-location (field) (mask) wrappers))
1083 (limit (funcall (or limit-fn (limit-fn)) (nlines))))
1084 (declare (fixnum location limit))
1085 (when (location-reserved-p location)
1086 (setq location (next-location location)))
1087 (dotimes-fixnum (i (1+ limit))
1088 (when (location-matches-wrappers-p location wrappers)
1089 (return-from probe-cache (or (not (valuep))
1090 (location-value location))))
1091 (setq location (next-location location)))
1092 (dolist (entry (overflow))
1093 (when (equal (car entry) wrappers)
1094 (return-from probe-cache (or (not (valuep))
1098 (defun map-cache (function cache &optional set-p)
1099 (with-local-cache-functions (cache)
1100 (let ((set-p (and set-p (valuep))))
1101 (dotimes-fixnum (i (nlines) cache)
1102 (unless (or (line-reserved-p i) (not (line-valid-p i nil)))
1103 (let ((value (funcall function (line-wrappers i) (line-value i))))
1105 (setf (cache-vector-ref (vector) (+ (line-location i) (nkeys)))
1107 (dolist (entry (overflow))
1108 (let ((value (funcall function (car entry) (cdr entry))))
1110 (setf (cdr entry) value))))))
1113 (defun cache-count (cache)
1114 (with-local-cache-functions (cache)
1116 (declare (fixnum count))
1117 (dotimes-fixnum (i (nlines) count)
1118 (unless (line-reserved-p i)
1119 (when (line-full-p i)
1122 (defun entry-in-cache-p (cache wrappers value)
1123 (declare (ignore value))
1124 (with-local-cache-functions (cache)
1125 (dotimes-fixnum (i (nlines))
1126 (unless (line-reserved-p i)
1127 (when (equal (line-wrappers i) wrappers)
1130 ;;; returns T or NIL
1131 (defun fill-cache-p (forcep cache wrappers value)
1132 (with-local-cache-functions (cache)
1133 (let* ((location (compute-primary-cache-location (field) (mask) wrappers))
1134 (primary (location-line location)))
1135 (declare (fixnum location primary))
1136 (multiple-value-bind (free emptyp)
1137 (find-free-cache-line primary cache wrappers)
1138 (when (or forcep emptyp)
1140 (push (cons (line-wrappers free) (line-value free))
1141 (cache-overflow cache)))
1142 ;;(fill-line free wrappers value)
1144 (declare (fixnum line))
1145 (when (line-reserved-p line)
1146 (error "attempt to fill a reserved line"))
1147 (let ((loc (line-location line))
1148 (cache-vector (vector)))
1149 (declare (fixnum loc) (simple-vector cache-vector))
1150 (cond ((= (nkeys) 1)
1151 (setf (cache-vector-ref cache-vector loc) wrappers)
1153 (setf (cache-vector-ref cache-vector (1+ loc)) value)))
1156 (declare (fixnum i))
1157 (dolist (w wrappers)
1158 (setf (cache-vector-ref cache-vector (+ loc i)) w)
1159 (setq i (the fixnum (1+ i)))))
1161 (setf (cache-vector-ref cache-vector (+ loc (nkeys)))
1163 (maybe-check-cache cache))))))))
1165 (defun fill-cache-from-cache-p (forcep cache from-cache from-line)
1166 (declare (fixnum from-line))
1167 (with-local-cache-functions (cache)
1168 (let ((primary (location-line
1169 (compute-primary-cache-location-from-location
1170 cache (line-location from-line) from-cache))))
1171 (declare (fixnum primary))
1172 (multiple-value-bind (free emptyp)
1173 (find-free-cache-line primary cache)
1174 (when (or forcep emptyp)
1176 (push (cons (line-wrappers free) (line-value free))
1177 (cache-overflow cache)))
1178 ;;(transfer-line from-cache-vector from-line cache-vector free)
1179 (let ((from-cache-vector (cache-vector from-cache))
1180 (to-cache-vector (vector))
1182 (declare (fixnum to-line))
1183 (if (line-reserved-p to-line)
1184 (error "transferring something into a reserved cache line")
1185 (let ((from-loc (line-location from-line))
1186 (to-loc (line-location to-line)))
1187 (declare (fixnum from-loc to-loc))
1188 (modify-cache to-cache-vector
1189 (dotimes-fixnum (i (line-size))
1190 (setf (cache-vector-ref to-cache-vector
1192 (cache-vector-ref from-cache-vector
1193 (+ from-loc i)))))))
1194 (maybe-check-cache cache)))))))
1196 ;;; Returns NIL or (values <field> <cache-vector>)
1198 ;;; This is only called when it isn't possible to put the entry in the
1199 ;;; cache the easy way. That is, this function assumes that
1200 ;;; FILL-CACHE-P has been called as returned NIL.
1202 ;;; If this returns NIL, it means that it wasn't possible to find a
1203 ;;; wrapper field for which all of the entries could be put in the
1204 ;;; cache (within the limit).
1205 (defun adjust-cache (cache wrappers value free-old-cache-p)
1206 (with-local-cache-functions (cache)
1207 (let ((ncache (get-cache-from-cache cache (nlines) (field))))
1208 (do ((nfield (cache-field ncache) (next-wrapper-cache-number-index nfield)))
1209 ((null nfield) (free-cache ncache) nil)
1210 (setf (cache-field ncache) nfield)
1211 (labels ((try-one-fill-from-line (line)
1212 (fill-cache-from-cache-p nil ncache cache line))
1213 (try-one-fill (wrappers value)
1214 (fill-cache-p nil ncache wrappers value)))
1215 (if (and (dotimes-fixnum (i (nlines) t)
1216 (when (and (null (line-reserved-p i))
1217 (line-valid-p i wrappers))
1218 (unless (try-one-fill-from-line i) (return nil))))
1219 (dolist (wrappers+value (cache-overflow cache) t)
1220 (unless (try-one-fill (car wrappers+value) (cdr wrappers+value))
1222 (try-one-fill wrappers value))
1223 (progn (when free-old-cache-p (free-cache cache))
1224 (return (maybe-check-cache ncache)))
1225 (flush-cache-vector-internal (cache-vector ncache))))))))
1227 ;;; returns: (values <cache>)
1228 (defun expand-cache (cache wrappers value free-old-cache-p)
1229 ;;(declare (values cache))
1230 (with-local-cache-functions (cache)
1231 (let ((ncache (get-cache-from-cache cache (* (nlines) 2))))
1232 (labels ((do-one-fill-from-line (line)
1233 (unless (fill-cache-from-cache-p nil ncache cache line)
1234 (do-one-fill (line-wrappers line) (line-value line))))
1235 (do-one-fill (wrappers value)
1236 (setq ncache (or (adjust-cache ncache wrappers value t)
1237 (fill-cache-p t ncache wrappers value))))
1238 (try-one-fill (wrappers value)
1239 (fill-cache-p nil ncache wrappers value)))
1240 (dotimes-fixnum (i (nlines))
1241 (when (and (null (line-reserved-p i))
1242 (line-valid-p i wrappers))
1243 (do-one-fill-from-line i)))
1244 (dolist (wrappers+value (cache-overflow cache))
1245 (unless (try-one-fill (car wrappers+value) (cdr wrappers+value))
1246 (do-one-fill (car wrappers+value) (cdr wrappers+value))))
1247 (unless (try-one-fill wrappers value)
1248 (do-one-fill wrappers value))
1249 (when free-old-cache-p (free-cache cache))
1250 (maybe-check-cache ncache)))))
1252 ;;; This is the heart of the cache filling mechanism. It implements
1253 ;;; the decisions about where entries are placed.
1255 ;;; Find a line in the cache at which a new entry can be inserted.
1258 ;;; <empty?> is <line> in fact empty?
1259 (defun find-free-cache-line (primary cache &optional wrappers)
1260 ;;(declare (values line empty?))
1261 (declare (fixnum primary))
1262 (with-local-cache-functions (cache)
1263 (when (line-reserved-p primary) (setq primary (next-line primary)))
1264 (let ((limit (funcall (limit-fn) (nlines)))
1267 (p primary) (s primary))
1268 (declare (fixnum p s limit))
1271 ;; Try to find a free line starting at <s>. <p> is the
1272 ;; primary line of the entry we are finding a free
1273 ;; line for, it is used to compute the separations.
1274 (do* ((line s (next-line line))
1275 (nsep (line-separation p s) (1+ nsep)))
1277 (declare (fixnum line nsep))
1278 (when (null (line-valid-p line wrappers)) ;If this line is empty or
1279 (push line lines) ;invalid, just use it.
1280 (return-from find-free))
1281 (when (and wrappedp (>= line primary))
1282 ;; have gone all the way around the cache, time to quit
1283 (return-from find-free-cache-line (values primary nil)))
1284 (let ((osep (line-separation (line-primary line) line)))
1285 (when (>= osep limit)
1286 (return-from find-free-cache-line (values primary nil)))
1287 (when (cond ((= nsep limit) t)
1288 ((= nsep osep) (zerop (random 2)))
1291 ;; See whether we can displace what is in this line so that we
1292 ;; can use the line.
1293 (when (= line (the fixnum (1- (nlines)))) (setq wrappedp t))
1294 (setq p (line-primary line))
1295 (setq s (next-line line))
1298 (when (= line (the fixnum (1- (nlines)))) (setq wrappedp t)))))
1299 ;; Do all the displacing.
1301 (when (null (cdr lines)) (return nil))
1302 (let ((dline (pop lines))
1304 (declare (fixnum dline line))
1305 ;;Copy from line to dline (dline is known to be free).
1306 (let ((from-loc (line-location line))
1307 (to-loc (line-location dline))
1308 (cache-vector (vector)))
1309 (declare (fixnum from-loc to-loc) (simple-vector cache-vector))
1310 (modify-cache cache-vector
1311 (dotimes-fixnum (i (line-size))
1312 (setf (cache-vector-ref cache-vector
1314 (cache-vector-ref cache-vector
1316 (setf (cache-vector-ref cache-vector
1319 (values (car lines) t))))
1321 (defun default-limit-fn (nlines)
1327 (defvar *empty-cache* (make-cache)) ; for defstruct slot initial value forms
1329 ;;; Pre-allocate generic function caches. The hope is that this will
1330 ;;; put them nicely together in memory, and that that may be a win. Of
1331 ;;; course the first GC copy will probably blow that out, this really
1332 ;;; wants to be wrapped in something that declares the area static.
1334 ;;; This preallocation only creates about 25% more caches than PCL
1335 ;;; itself uses. Some ports may want to preallocate some more of
1338 ;;; KLUDGE: Isn't something very similar going on in precom1.lisp? Do
1339 ;;; we need it both here and there? Why? -- WHN 19991203
1340 (eval-when (:load-toplevel)
1341 (dolist (n-size '((1 513)(3 257)(3 129)(14 128)(6 65)(2 64)(7 33)(16 32)
1342 (16 17)(32 16)(64 9)(64 8)(6 5)(128 4)(35 2)))
1343 (let ((n (car n-size))
1344 (size (cadr n-size)))
1345 (mapcar #'free-cache-vector
1346 (mapcar #'get-cache-vector
1347 (make-list n :initial-element size))))))
1349 (defun caches-to-allocate ()
1350 (sort (let ((l nil))
1351 (maphash #'(lambda (size entry)
1352 (push (list (car entry) size) l))
1353 sb-pcl::*free-caches*)