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 ;;; Note that for SBCL, as for CMU CL, the WRAPPER of a built-in or
260 ;;; structure class will be some other kind of SB-KERNEL:LAYOUT, but
261 ;;; this shouldn't matter, since the only two slots that WRAPPER adds
262 ;;; are meaningless in those cases.
264 (:include sb-kernel:layout
265 ;; KLUDGE: In CMU CL, the initialization default
266 ;; for LAYOUT-INVALID was NIL. In SBCL, that has
267 ;; changed to :UNINITIALIZED, but PCL code might
268 ;; still expect NIL for the initialization
269 ;; default of WRAPPER-INVALID. Instead of trying
270 ;; to find out, I just overrode the LAYOUT
271 ;; default here. -- WHN 19991204
273 (:conc-name %wrapper-)
274 (:constructor make-wrapper-internal)
276 (instance-slots-layout nil :type list)
277 (class-slots nil :type list))
278 #-sb-fluid (declaim (sb-ext:freeze-type wrapper))
280 (defmacro wrapper-class (wrapper)
281 `(sb-kernel:class-pcl-class (sb-kernel:layout-class ,wrapper)))
282 (defmacro wrapper-no-of-instance-slots (wrapper)
283 `(sb-kernel:layout-length ,wrapper))
285 ;;; WRAPPER-STATE returns T (not generalized boolean, but T exactly)
286 ;;; iff the wrapper is valid. Any other return value denotes some
287 ;;; invalid state. Special conventions have been set up for certain
288 ;;; invalid states, e.g. obsoleteness or flushedness, but I (WHN
289 ;;; 19991204) haven't been motivated to reverse engineer them from the
290 ;;; code and document them here.
292 ;;; FIXME: This is awkward and unmnemonic. There is a function
293 ;;; (INVALID-WRAPPER-P) to test this return result abstractly for
294 ;;; invalidness but it's not called consistently; the functions that
295 ;;; need to know whether a wrapper is invalid often test (EQ
296 ;;; (WRAPPER-STATE X) T), ick. It would be good to use the abstract
297 ;;; test instead. It would probably be even better to switch the sense
298 ;;; of the WRAPPER-STATE function, renaming it to WRAPPER-INVALID and
299 ;;; making it synonymous with LAYOUT-INVALID. Then the
300 ;;; INVALID-WRAPPER-P function would become trivial and would go away
301 ;;; (replaced with WRAPPER-INVALID), since all the various invalid
302 ;;; wrapper states would become generalized boolean "true" values. --
304 #-sb-fluid (declaim (inline wrapper-state (setf wrapper-state)))
305 (defun wrapper-state (wrapper)
306 (let ((invalid (sb-kernel:layout-invalid wrapper)))
307 (cond ((null invalid)
310 ;; some non-PCL object. INVALID is probably :INVALID. We
311 ;; should arguably compute the new wrapper here instead of
312 ;; returning NIL, but we don't bother, since
313 ;; OBSOLETE-INSTANCE-TRAP can't use it.
317 (defun (setf wrapper-state) (new-value wrapper)
318 (setf (sb-kernel:layout-invalid wrapper)
323 (defmacro wrapper-instance-slots-layout (wrapper)
324 `(%wrapper-instance-slots-layout ,wrapper))
325 (defmacro wrapper-class-slots (wrapper)
326 `(%wrapper-class-slots ,wrapper))
327 (defmacro wrapper-cache-number-vector (x) x)
329 ;;; This is called in BRAID when we are making wrappers for classes
330 ;;; whose slots are not initialized yet, and which may be built-in
331 ;;; classes. We pass in the class name in addition to the class.
332 (defun boot-make-wrapper (length name &optional class)
333 (let ((found (cl:find-class name nil)))
336 (unless (sb-kernel:class-pcl-class found)
337 (setf (sb-kernel:class-pcl-class found) class))
338 (assert (eq (sb-kernel:class-pcl-class found) class))
339 (let ((layout (sb-kernel:class-layout found)))
343 (make-wrapper-internal
345 :class (sb-kernel:make-standard-class :name name :pcl-class class))))))
347 ;;; The following variable may be set to a standard-class that has
348 ;;; already been created by the lisp code and which is to be redefined
349 ;;; by PCL. This allows standard-classes to be defined and used for
350 ;;; type testing and dispatch before PCL is loaded.
351 (defvar *pcl-class-boot* nil)
353 ;;; In SBCL, as in CMU CL, the layouts (a.k.a wrappers) for built-in
354 ;;; and structure classes already exist when PCL is initialized, so we
355 ;;; don't necessarily always make a wrapper. Also, we help maintain
356 ;;; the mapping between cl:class and pcl::class objects.
357 (defun make-wrapper (length class)
359 ((typep class 'std-class)
360 (make-wrapper-internal
363 (let ((owrap (class-wrapper class)))
365 (sb-kernel:layout-class owrap))
366 ((*subtypep (class-of class)
367 *the-class-standard-class*)
368 (cond ((and *pcl-class-boot*
369 (eq (slot-value class 'name) *pcl-class-boot*))
370 (let ((found (cl:find-class (slot-value class 'name))))
371 (unless (sb-kernel:class-pcl-class found)
372 (setf (sb-kernel:class-pcl-class found) class))
373 (assert (eq (sb-kernel:class-pcl-class found) class))
376 (sb-kernel:make-standard-class :pcl-class class))))
378 (sb-kernel:make-random-pcl-class :pcl-class class))))))
380 (let* ((found (cl:find-class (slot-value class 'name)))
381 (layout (sb-kernel:class-layout found)))
382 (unless (sb-kernel:class-pcl-class found)
383 (setf (sb-kernel:class-pcl-class found) class))
384 (assert (eq (sb-kernel:class-pcl-class found) class))
388 ;;; FIXME: The immediately following macros could become inline functions.
390 (defmacro first-wrapper-cache-number-index ()
393 (defmacro next-wrapper-cache-number-index (field-number)
394 `(and (< ,field-number #.(1- wrapper-cache-number-vector-length))
397 (defmacro cache-number-vector-ref (cnv n)
398 `(wrapper-cache-number-vector-ref ,cnv ,n))
400 (defmacro wrapper-cache-number-vector-ref (wrapper n)
401 `(sb-kernel:layout-clos-hash ,wrapper ,n))
403 (defmacro class-no-of-instance-slots (class)
404 `(wrapper-no-of-instance-slots (class-wrapper ,class)))
406 (defmacro wrapper-class* (wrapper)
407 `(let ((wrapper ,wrapper))
408 (or (wrapper-class wrapper)
409 (find-structure-class
410 (cl:class-name (sb-kernel:layout-class wrapper))))))
412 ;;; The wrapper cache machinery provides general mechanism for
413 ;;; trapping on the next access to any instance of a given class. This
414 ;;; mechanism is used to implement the updating of instances when the
415 ;;; class is redefined (MAKE-INSTANCES-OBSOLETE). The same mechanism
416 ;;; is also used to update generic function caches when there is a
417 ;;; change to the superclasses of a class.
419 ;;; Basically, a given wrapper can be valid or invalid. If it is
420 ;;; invalid, it means that any attempt to do a wrapper cache lookup
421 ;;; using the wrapper should trap. Also, methods on
422 ;;; SLOT-VALUE-USING-CLASS check the wrapper validity as well. This is
423 ;;; done by calling CHECK-WRAPPER-VALIDITY.
425 ;;; FIXME: could become inline function
426 (defmacro invalid-wrapper-p (wrapper)
427 `(neq (wrapper-state ,wrapper) t))
429 (defvar *previous-nwrappers* (make-hash-table))
431 (defun invalidate-wrapper (owrapper state nwrapper)
434 (let ((new-previous ()))
435 ;; First off, a previous call to INVALIDATE-WRAPPER may have
436 ;; recorded OWRAPPER as an NWRAPPER to update to. Since
437 ;; OWRAPPER is about to be invalid, it no longer makes sense to
440 ;; We go back and change the previously invalidated wrappers so
441 ;; that they will now update directly to NWRAPPER. This
442 ;; corresponds to a kind of transitivity of wrapper updates.
443 (dolist (previous (gethash owrapper *previous-nwrappers*))
444 (when (eq state ':obsolete)
445 (setf (car previous) ':obsolete))
446 (setf (cadr previous) nwrapper)
447 (push previous new-previous))
449 (let ((ocnv (wrapper-cache-number-vector owrapper)))
450 (dotimes (i sb-kernel:layout-clos-hash-length)
451 (setf (cache-number-vector-ref ocnv i) 0)))
452 (push (setf (wrapper-state owrapper) (list state nwrapper))
455 (setf (gethash owrapper *previous-nwrappers*) ()
456 (gethash nwrapper *previous-nwrappers*) new-previous)))))
458 (defun check-wrapper-validity (instance)
459 (let* ((owrapper (wrapper-of instance))
460 (state (wrapper-state owrapper)))
466 (flush-cache-trap owrapper (cadr state) instance))
468 (obsolete-instance-trap owrapper (cadr state) instance)))))
469 ;; This little bit of error checking is superfluous. It only
470 ;; checks to see whether the person who implemented the trap
471 ;; handling screwed up. Since that person is hacking
472 ;; internal PCL code, and is not a user, this should be
473 ;; needless. Also, since this directly slows down instance
474 ;; update and generic function cache refilling, feel free to
475 ;; take it out sometime soon.
477 ;; FIXME: We probably need to add a #+SB-PARANOID feature to
478 ;; make stuff like this optional. Until then, it stays in.
479 (cond ((neq nwrapper (wrapper-of instance))
480 (error "wrapper returned from trap not wrapper of instance"))
481 ((invalid-wrapper-p nwrapper)
482 (error "wrapper returned from trap invalid")))
485 (defmacro check-wrapper-validity1 (object)
486 (let ((owrapper (gensym)))
487 `(let ((,owrapper (sb-kernel:layout-of object)))
488 (if (sb-kernel:layout-invalid ,owrapper)
489 (check-wrapper-validity ,object)
492 (defvar *free-caches* nil)
494 (defun get-cache (nkeys valuep limit-fn nlines)
495 (let ((cache (or (sb-sys:without-interrupts (pop *free-caches*))
497 (declare (type cache cache))
498 (multiple-value-bind (cache-mask actual-size line-size nlines)
499 (compute-cache-parameters nkeys valuep nlines)
500 (setf (cache-nkeys cache) nkeys
501 (cache-valuep cache) valuep
502 (cache-nlines cache) nlines
503 (cache-field cache) (first-wrapper-cache-number-index)
504 (cache-limit-fn cache) limit-fn
505 (cache-mask cache) cache-mask
506 (cache-size cache) actual-size
507 (cache-line-size cache) line-size
508 (cache-max-location cache) (let ((line (1- nlines)))
511 (1+ (* line line-size))))
512 (cache-vector cache) (get-cache-vector actual-size)
513 (cache-overflow cache) nil)
516 (defun get-cache-from-cache (old-cache new-nlines
517 &optional (new-field (first-wrapper-cache-number-index)))
518 (let ((nkeys (cache-nkeys old-cache))
519 (valuep (cache-valuep old-cache))
520 (cache (or (sb-sys:without-interrupts (pop *free-caches*))
522 (declare (type cache cache))
523 (multiple-value-bind (cache-mask actual-size line-size nlines)
524 (if (= new-nlines (cache-nlines old-cache))
525 (values (cache-mask old-cache) (cache-size old-cache)
526 (cache-line-size old-cache) (cache-nlines old-cache))
527 (compute-cache-parameters nkeys valuep new-nlines))
528 (setf (cache-owner cache) (cache-owner old-cache)
529 (cache-nkeys cache) nkeys
530 (cache-valuep cache) valuep
531 (cache-nlines cache) nlines
532 (cache-field cache) new-field
533 (cache-limit-fn cache) (cache-limit-fn old-cache)
534 (cache-mask cache) cache-mask
535 (cache-size cache) actual-size
536 (cache-line-size cache) line-size
537 (cache-max-location cache) (let ((line (1- nlines)))
540 (1+ (* line line-size))))
541 (cache-vector cache) (get-cache-vector actual-size)
542 (cache-overflow cache) nil)
545 (defun copy-cache (old-cache)
546 (let* ((new-cache (copy-cache-internal old-cache))
547 (size (cache-size old-cache))
548 (old-vector (cache-vector old-cache))
549 (new-vector (get-cache-vector size)))
550 (declare (simple-vector old-vector new-vector))
551 (dotimes-fixnum (i size)
552 (setf (svref new-vector i) (svref old-vector i)))
553 (setf (cache-vector new-cache) new-vector)
556 (defun free-cache (cache)
557 (free-cache-vector (cache-vector cache))
558 (setf (cache-vector cache) #())
559 (setf (cache-owner cache) nil)
560 (push cache *free-caches*)
563 (defun compute-line-size (x)
564 (power-of-two-ceiling x))
566 (defun compute-cache-parameters (nkeys valuep nlines-or-cache-vector)
567 ;;(declare (values cache-mask actual-size line-size nlines))
568 (declare (fixnum nkeys))
570 (let* ((line-size (if valuep 2 1))
571 (cache-size (if (typep nlines-or-cache-vector 'fixnum)
575 (power-of-two-ceiling
576 nlines-or-cache-vector))))
577 (cache-vector-size nlines-or-cache-vector))))
578 (declare (fixnum line-size cache-size))
579 (values (logxor (the fixnum (1- cache-size)) (the fixnum (1- line-size)))
582 (the fixnum (floor cache-size line-size))))
583 (let* ((line-size (power-of-two-ceiling (if valuep (1+ nkeys) nkeys)))
584 (cache-size (if (typep nlines-or-cache-vector 'fixnum)
588 (power-of-two-ceiling
589 nlines-or-cache-vector))))
590 (1- (cache-vector-size nlines-or-cache-vector)))))
591 (declare (fixnum line-size cache-size))
592 (values (logxor (the fixnum (1- cache-size)) (the fixnum (1- line-size)))
593 (the fixnum (1+ cache-size))
595 (the fixnum (floor cache-size line-size))))))
597 ;;; the various implementations of computing a primary cache location from
598 ;;; wrappers. Because some implementations of this must run fast there are
599 ;;; several implementations of the same algorithm.
601 ;;; The algorithm is:
603 ;;; SUM over the wrapper cache numbers,
604 ;;; ENSURING that the result is a fixnum
605 ;;; MASK the result against the mask argument.
607 ;;; COMPUTE-PRIMARY-CACHE-LOCATION
609 ;;; The basic functional version. This is used by the cache miss code to
610 ;;; compute the primary location of an entry.
611 (defun compute-primary-cache-location (field mask wrappers)
613 (declare (type field-type field) (fixnum mask))
614 (if (not (listp wrappers))
616 (the fixnum (wrapper-cache-number-vector-ref wrappers field)))
617 (let ((location 0) (i 0))
618 (declare (fixnum location i))
619 (dolist (wrapper wrappers)
620 ;; First add the cache number of this wrapper to location.
621 (let ((wrapper-cache-number (wrapper-cache-number-vector-ref wrapper
623 (declare (fixnum wrapper-cache-number))
624 (if (zerop wrapper-cache-number)
625 (return-from compute-primary-cache-location 0)
627 (the fixnum (+ location wrapper-cache-number)))))
628 ;; Then, if we are working with lots of wrappers, deal with
629 ;; the wrapper-cache-number-mask stuff.
630 (when (and (not (zerop i))
631 (zerop (mod i wrapper-cache-number-adds-ok)))
633 (logand location wrapper-cache-number-mask)))
635 (the fixnum (1+ (logand mask location))))))
637 ;;; COMPUTE-PRIMARY-CACHE-LOCATION-FROM-LOCATION
639 ;;; This version is called on a cache line. It fetches the wrappers
640 ;;; from the cache line and determines the primary location. Various
641 ;;; parts of the cache filling code call this to determine whether it
642 ;;; is appropriate to displace a given cache entry.
644 ;;; If this comes across a wrapper whose CACHE-NO is 0, it returns the
645 ;;; symbol invalid to suggest to its caller that it would be provident
646 ;;; to blow away the cache line in question.
647 (defun compute-primary-cache-location-from-location (to-cache
650 (from-cache to-cache))
651 (declare (type cache to-cache from-cache) (fixnum from-location))
653 (cache-vector (cache-vector from-cache))
654 (field (cache-field to-cache))
655 (mask (cache-mask to-cache))
656 (nkeys (cache-nkeys to-cache)))
657 (declare (type field-type field) (fixnum result mask nkeys)
658 (simple-vector cache-vector))
659 (dotimes-fixnum (i nkeys)
660 (let* ((wrapper (cache-vector-ref cache-vector (+ i from-location)))
661 (wcn (wrapper-cache-number-vector-ref wrapper field)))
662 (declare (fixnum wcn))
663 (setq result (+ result wcn)))
664 (when (and (not (zerop i))
665 (zerop (mod i wrapper-cache-number-adds-ok)))
666 (setq result (logand result wrapper-cache-number-mask))))
669 (the fixnum (1+ (logand mask result))))))
671 ;;; NIL means nothing so far, no actual arg info has NILs
673 ;;; CLASS seen all sorts of metaclasses
674 ;;; (specifically, more than one of the next 4 values)
675 ;;; T means everything so far is the class T
676 ;;; STANDARD-CLASS seen only standard classes
677 ;;; BUILT-IN-CLASS seen only built in classes
678 ;;; STRUCTURE-CLASS seen only structure classes
679 (defun raise-metatype (metatype new-specializer)
680 (let ((slot (find-class 'slot-class))
681 (std (find-class 'std-class))
682 (standard (find-class 'standard-class))
683 (fsc (find-class 'funcallable-standard-class))
684 (structure (find-class 'structure-class))
685 (built-in (find-class 'built-in-class)))
686 (flet ((specializer->metatype (x)
687 (let ((meta-specializer
688 (if (eq *boot-state* 'complete)
689 (class-of (specializer-class x))
691 (cond ((eq x *the-class-t*) t)
692 ((*subtypep meta-specializer std)
694 ((*subtypep meta-specializer standard)
696 ((*subtypep meta-specializer fsc)
698 ((*subtypep meta-specializer structure)
700 ((*subtypep meta-specializer built-in)
702 ((*subtypep meta-specializer slot)
704 (t (error "PCL cannot handle the specializer ~S (meta-specializer ~S)."
706 meta-specializer))))))
707 ;; We implement the following table. The notation is
708 ;; that X and Y are distinct meta specializer names.
710 ;; NIL <anything> ===> <anything>
713 (let ((new-metatype (specializer->metatype new-specializer)))
714 (cond ((eq new-metatype 'slot-instance) 'class)
715 ((null metatype) new-metatype)
716 ((eq metatype new-metatype) new-metatype)
719 (defmacro with-dfun-wrappers ((args metatypes)
720 (dfun-wrappers invalid-wrapper-p
721 &optional wrappers classes types)
722 invalid-arguments-form
724 `(let* ((args-tail ,args) (,invalid-wrapper-p nil) (invalid-arguments-p nil)
725 (,dfun-wrappers nil) (dfun-wrappers-tail nil)
727 `((wrappers-rev nil) (types-rev nil) (classes-rev nil))))
728 (dolist (mt ,metatypes)
730 (setq invalid-arguments-p t)
732 (let* ((arg (pop args-tail))
735 `((class *the-class-t*)
738 (setq wrapper (wrapper-of arg))
739 (when (invalid-wrapper-p wrapper)
740 (setq ,invalid-wrapper-p t)
741 (setq wrapper (check-wrapper-validity arg)))
742 (cond ((null ,dfun-wrappers)
743 (setq ,dfun-wrappers wrapper))
744 ((not (consp ,dfun-wrappers))
745 (setq dfun-wrappers-tail (list wrapper))
746 (setq ,dfun-wrappers (cons ,dfun-wrappers dfun-wrappers-tail)))
748 (let ((new-dfun-wrappers-tail (list wrapper)))
749 (setf (cdr dfun-wrappers-tail) new-dfun-wrappers-tail)
750 (setf dfun-wrappers-tail new-dfun-wrappers-tail))))
752 `((setq class (wrapper-class* wrapper))
753 (setq type `(class-eq ,class)))))
755 `((push wrapper wrappers-rev)
756 (push class classes-rev)
757 (push type types-rev)))))
758 (if invalid-arguments-p
759 ,invalid-arguments-form
760 (let* (,@(when wrappers
761 `((,wrappers (nreverse wrappers-rev))
762 (,classes (nreverse classes-rev))
763 (,types (mapcar #'(lambda (class)
768 ;;;; some support stuff for getting a hold of symbols that we need when
769 ;;;; building the discriminator codes. It's OK for these to be interned
770 ;;;; symbols because we don't capture any user code in the scope in which
771 ;;;; these symbols are bound.
773 (defvar *dfun-arg-symbols* '(.ARG0. .ARG1. .ARG2. .ARG3.))
775 (defun dfun-arg-symbol (arg-number)
776 (or (nth arg-number (the list *dfun-arg-symbols*))
777 (intern (format nil ".ARG~A." arg-number) *pcl-package*)))
779 (defvar *slot-vector-symbols* '(.SLOTS0. .SLOTS1. .SLOTS2. .SLOTS3.))
781 (defun slot-vector-symbol (arg-number)
782 (or (nth arg-number (the list *slot-vector-symbols*))
783 (intern (format nil ".SLOTS~A." arg-number) *pcl-package*)))
785 (defun make-dfun-lambda-list (metatypes applyp)
786 (gathering1 (collecting)
787 (iterate ((i (interval :from 0))
788 (s (list-elements metatypes)))
790 (gather1 (dfun-arg-symbol i)))
793 (gather1 '.dfun-rest-arg.))))
795 (defun make-dlap-lambda-list (metatypes applyp)
796 (gathering1 (collecting)
797 (iterate ((i (interval :from 0))
798 (s (list-elements metatypes)))
800 (gather1 (dfun-arg-symbol i)))
804 (defun make-emf-call (metatypes applyp fn-variable &optional emf-type)
806 (gathering1 (collecting)
807 (iterate ((i (interval :from 0))
808 (s (list-elements metatypes)))
810 (gather1 (dfun-arg-symbol i))))))
811 `(,(if (eq emf-type 'fast-method-call)
812 'invoke-effective-method-function-fast
813 'invoke-effective-method-function)
814 ,fn-variable ,applyp ,@required ,@(when applyp `(.dfun-rest-arg.)))))
816 (defun make-dfun-call (metatypes applyp fn-variable)
818 (gathering1 (collecting)
819 (iterate ((i (interval :from 0))
820 (s (list-elements metatypes)))
822 (gather1 (dfun-arg-symbol i))))))
824 `(function-apply ,fn-variable ,@required .dfun-rest-arg.)
825 `(function-funcall ,fn-variable ,@required))))
827 (defun make-dfun-arg-list (metatypes applyp)
829 (gathering1 (collecting)
830 (iterate ((i (interval :from 0))
831 (s (list-elements metatypes)))
833 (gather1 (dfun-arg-symbol i))))))
835 `(list* ,@required .dfun-rest-arg.)
836 `(list ,@required))))
838 (defun make-fast-method-call-lambda-list (metatypes applyp)
839 (gathering1 (collecting)
841 (gather1 '.next-method-call.)
842 (iterate ((i (interval :from 0))
843 (s (list-elements metatypes)))
845 (gather1 (dfun-arg-symbol i)))
847 (gather1 '.dfun-rest-arg.))))
849 ;;;; a comment from some PCL implementor:
850 ;;;; Its too bad Common Lisp compilers freak out when you have a
851 ;;;; DEFUN with a lot of LABELS in it. If I could do that I could
852 ;;;; make this code much easier to read and work with.
854 ;;;; In the absence of that, the following little macro makes the
855 ;;;; code that follows a little bit more reasonable. I would like to
856 ;;;; add that having to practically write my own compiler in order to
857 ;;;; get just this simple thing is something of a drag.
859 ;;;; KLUDGE: Maybe we could actually implement this as LABELS now,
860 ;;;; since AFAIK CMU CL doesn't freak out when you have a DEFUN with a
861 ;;;; lot of LABELS in it (and if it does we can fix it instead of
862 ;;;; working around it). -- WHN 19991204
864 (eval-when (:compile-toplevel :load-toplevel :execute)
868 ;;; FIXME: should be undefined after bootstrapping
869 (defparameter *local-cache-functions*
871 (nkeys () (cache-nkeys .cache.))
872 (line-size () (cache-line-size .cache.))
873 (vector () (cache-vector .cache.))
874 (valuep () (cache-valuep .cache.))
875 (nlines () (cache-nlines .cache.))
876 (max-location () (cache-max-location .cache.))
877 (limit-fn () (cache-limit-fn .cache.))
878 (size () (cache-size .cache.))
879 (mask () (cache-mask .cache.))
880 (field () (cache-field .cache.))
881 (overflow () (cache-overflow .cache.))
883 ;; Return T IFF this cache location is reserved. The only time
884 ;; this is true is for line number 0 of an nkeys=1 cache.
885 (line-reserved-p (line)
886 (declare (fixnum line))
889 (location-reserved-p (location)
890 (declare (fixnum location))
893 ;; Given a line number, return the cache location. This is the
894 ;; value that is the second argument to cache-vector-ref. Basically,
895 ;; this deals with the offset of nkeys>1 caches and multiplies
897 (line-location (line)
898 (declare (fixnum line))
899 (when (line-reserved-p line)
900 (error "Line is reserved."))
902 (the fixnum (* line (line-size)))
903 (the fixnum (1+ (the fixnum (* line (line-size)))))))
905 ;; Given a cache location, return the line. This is the inverse
907 (location-line (location)
908 (declare (fixnum location))
910 (floor location (line-size))
911 (floor (the fixnum (1- location)) (line-size))))
913 ;; Given a line number, return the wrappers stored at that line.
914 ;; As usual, if nkeys=1, this returns a single value. Only when
915 ;; nkeys>1 does it return a list. An error is signalled if the
917 (line-wrappers (line)
918 (declare (fixnum line))
919 (when (line-reserved-p line) (error "Line is reserved."))
920 (location-wrappers (line-location line)))
921 (location-wrappers (location) ; avoid multiplies caused by line-location
922 (declare (fixnum location))
924 (cache-vector-ref (vector) location)
925 (let ((list (make-list (nkeys)))
927 (declare (simple-vector vector))
928 (dotimes-fixnum (i (nkeys) list)
929 (setf (nth i list) (cache-vector-ref vector (+ location i)))))))
931 ;; Given a line number, return true IFF the line's
932 ;; wrappers are the same as wrappers.
933 (line-matches-wrappers-p (line wrappers)
934 (declare (fixnum line))
935 (and (not (line-reserved-p line))
936 (location-matches-wrappers-p (line-location line) wrappers)))
937 (location-matches-wrappers-p (loc wrappers) ; must not be reserved
938 (declare (fixnum loc))
939 (let ((cache-vector (vector)))
940 (declare (simple-vector cache-vector))
942 (eq wrappers (cache-vector-ref cache-vector loc))
943 (dotimes-fixnum (i (nkeys) t)
944 (unless (eq (pop wrappers)
945 (cache-vector-ref cache-vector (+ loc i)))
948 ;; Given a line number, return the value stored at that line.
949 ;; If valuep is NIL, this returns NIL. As with line-wrappers,
950 ;; an error is signalled if the line is reserved.
952 (declare (fixnum line))
953 (when (line-reserved-p line) (error "Line is reserved."))
954 (location-value (line-location line)))
955 (location-value (loc)
956 (declare (fixnum loc))
958 (cache-vector-ref (vector) (+ loc (nkeys)))))
960 ;; Given a line number, return true iff that line has data in
961 ;; it. The state of the wrappers stored in the line is not
962 ;; checked. An error is signalled if line is reserved.
964 (when (line-reserved-p line) (error "Line is reserved."))
965 (not (null (cache-vector-ref (vector) (line-location line)))))
967 ;; Given a line number, return true iff the line is full and
968 ;; there are no invalid wrappers in the line, and the line's
969 ;; wrappers are different from wrappers.
970 ;; An error is signalled if the line is reserved.
971 (line-valid-p (line wrappers)
972 (declare (fixnum line))
973 (when (line-reserved-p line) (error "Line is reserved."))
974 (location-valid-p (line-location line) wrappers))
975 (location-valid-p (loc wrappers)
976 (declare (fixnum loc))
977 (let ((cache-vector (vector))
978 (wrappers-mismatch-p (null wrappers)))
979 (declare (simple-vector cache-vector))
980 (dotimes-fixnum (i (nkeys) wrappers-mismatch-p)
981 (let ((wrapper (cache-vector-ref cache-vector (+ loc i))))
982 (when (or (null wrapper)
983 (invalid-wrapper-p wrapper))
985 (unless (and wrappers
987 (if (consp wrappers) (pop wrappers) wrappers)))
988 (setq wrappers-mismatch-p t))))))
990 ;; how many unreserved lines separate line-1 and line-2
991 (line-separation (line-1 line-2)
992 (declare (fixnum line-1 line-2))
993 (let ((diff (the fixnum (- line-2 line-1))))
994 (declare (fixnum diff))
996 (setq diff (+ diff (nlines)))
997 (when (line-reserved-p 0)
998 (setq diff (1- diff))))
1001 ;; Given a cache line, get the next cache line. This will not
1002 ;; return a reserved line.
1004 (declare (fixnum line))
1005 (if (= line (the fixnum (1- (nlines))))
1006 (if (line-reserved-p 0) 1 0)
1007 (the fixnum (1+ line))))
1008 (next-location (loc)
1009 (declare (fixnum loc))
1010 (if (= loc (max-location))
1014 (the fixnum (+ loc (line-size)))))
1016 ;; Given a line which has a valid entry in it, this will return
1017 ;; the primary cache line of the wrappers in that line. We just
1018 ;; call COMPUTE-PRIMARY-CACHE-LOCATION-FROM-LOCATION, this is an
1019 ;; easier packaging up of the call to it.
1020 (line-primary (line)
1021 (declare (fixnum line))
1022 (location-line (line-primary-location line)))
1023 (line-primary-location (line)
1024 (declare (fixnum line))
1025 (compute-primary-cache-location-from-location
1026 (cache) (line-location line)))))
1028 (defmacro with-local-cache-functions ((cache) &body body)
1029 `(let ((.cache. ,cache))
1030 (declare (type cache .cache.))
1031 (macrolet ,(mapcar #'(lambda (fn)
1032 `(,(car fn) ,(cadr fn)
1033 `(let (,,@(mapcar #'(lambda (var)
1037 *local-cache-functions*)
1042 ;;; Here is where we actually fill, recache and expand caches.
1044 ;;; The functions FILL-CACHE and PROBE-CACHE are the ONLY external
1045 ;;; entrypoints into this code.
1047 ;;; FILL-CACHE returns 1 value: a new cache
1049 ;;; a wrapper field number
1052 ;;; an absolute cache size (the size of the actual vector)
1053 ;;; It tries to re-adjust the cache every time it makes a new fill.
1054 ;;; The intuition here is that we want uniformity in the number of
1055 ;;; probes needed to find an entry. Furthermore, adjusting has the
1056 ;;; nice property of throwing out any entries that are invalid.
1057 (defvar *cache-expand-threshold* 1.25)
1059 (defun fill-cache (cache wrappers value &optional free-cache-p)
1061 ;; FILL-CACHE won't return if WRAPPERS is nil, might as well check..
1063 (error "fill-cache: WRAPPERS arg is NIL!"))
1065 (or (fill-cache-p nil cache wrappers value)
1066 (and (< (ceiling (* (cache-count cache) 1.25))
1067 (if (= (cache-nkeys cache) 1)
1068 (1- (cache-nlines cache))
1069 (cache-nlines cache)))
1070 (adjust-cache cache wrappers value free-cache-p))
1071 (expand-cache cache wrappers value free-cache-p)))
1073 (defvar *check-cache-p* nil)
1075 (defmacro maybe-check-cache (cache)
1077 (when *check-cache-p*
1078 (check-cache ,cache))
1081 (defun check-cache (cache)
1082 (with-local-cache-functions (cache)
1083 (let ((location (if (= (nkeys) 1) 0 1))
1084 (limit (funcall (limit-fn) (nlines))))
1085 (dotimes-fixnum (i (nlines) cache)
1086 (when (and (not (location-reserved-p location))
1088 (let* ((home-loc (compute-primary-cache-location-from-location
1090 (home (location-line (if (location-reserved-p home-loc)
1091 (next-location home-loc)
1093 (sep (when home (line-separation home i))))
1094 (when (and sep (> sep limit))
1095 (error "bad cache ~S ~@
1096 value at location ~D: ~D lines from its home. The limit is ~D."
1097 cache location sep limit))))
1098 (setq location (next-location location))))))
1100 (defun probe-cache (cache wrappers &optional default limit-fn)
1101 ;;(declare (values value))
1103 ;; FIXME: This and another earlier test on a WRAPPERS arg can
1104 ;; be compact assertoids.
1105 (error "WRAPPERS arg is NIL!"))
1106 (with-local-cache-functions (cache)
1107 (let* ((location (compute-primary-cache-location (field) (mask) wrappers))
1108 (limit (funcall (or limit-fn (limit-fn)) (nlines))))
1109 (declare (fixnum location limit))
1110 (when (location-reserved-p location)
1111 (setq location (next-location location)))
1112 (dotimes-fixnum (i (1+ limit))
1113 (when (location-matches-wrappers-p location wrappers)
1114 (return-from probe-cache (or (not (valuep))
1115 (location-value location))))
1116 (setq location (next-location location)))
1117 (dolist (entry (overflow))
1118 (when (equal (car entry) wrappers)
1119 (return-from probe-cache (or (not (valuep))
1123 (defun map-cache (function cache &optional set-p)
1124 (with-local-cache-functions (cache)
1125 (let ((set-p (and set-p (valuep))))
1126 (dotimes-fixnum (i (nlines) cache)
1127 (unless (or (line-reserved-p i) (not (line-valid-p i nil)))
1128 (let ((value (funcall function (line-wrappers i) (line-value i))))
1130 (setf (cache-vector-ref (vector) (+ (line-location i) (nkeys)))
1132 (dolist (entry (overflow))
1133 (let ((value (funcall function (car entry) (cdr entry))))
1135 (setf (cdr entry) value))))))
1138 (defun cache-count (cache)
1139 (with-local-cache-functions (cache)
1141 (declare (fixnum count))
1142 (dotimes-fixnum (i (nlines) count)
1143 (unless (line-reserved-p i)
1144 (when (line-full-p i)
1147 (defun entry-in-cache-p (cache wrappers value)
1148 (declare (ignore value))
1149 (with-local-cache-functions (cache)
1150 (dotimes-fixnum (i (nlines))
1151 (unless (line-reserved-p i)
1152 (when (equal (line-wrappers i) wrappers)
1155 ;;; returns T or NIL
1156 (defun fill-cache-p (forcep cache wrappers value)
1157 (with-local-cache-functions (cache)
1158 (let* ((location (compute-primary-cache-location (field) (mask) wrappers))
1159 (primary (location-line location)))
1160 (declare (fixnum location primary))
1161 (multiple-value-bind (free emptyp)
1162 (find-free-cache-line primary cache wrappers)
1163 (when (or forcep emptyp)
1165 (push (cons (line-wrappers free) (line-value free))
1166 (cache-overflow cache)))
1167 ;;(fill-line free wrappers value)
1169 (declare (fixnum line))
1170 (when (line-reserved-p line)
1171 (error "attempt to fill a reserved line"))
1172 (let ((loc (line-location line))
1173 (cache-vector (vector)))
1174 (declare (fixnum loc) (simple-vector cache-vector))
1175 (cond ((= (nkeys) 1)
1176 (setf (cache-vector-ref cache-vector loc) wrappers)
1178 (setf (cache-vector-ref cache-vector (1+ loc)) value)))
1181 (declare (fixnum i))
1182 (dolist (w wrappers)
1183 (setf (cache-vector-ref cache-vector (+ loc i)) w)
1184 (setq i (the fixnum (1+ i)))))
1186 (setf (cache-vector-ref cache-vector (+ loc (nkeys)))
1188 (maybe-check-cache cache))))))))
1190 (defun fill-cache-from-cache-p (forcep cache from-cache from-line)
1191 (declare (fixnum from-line))
1192 (with-local-cache-functions (cache)
1193 (let ((primary (location-line
1194 (compute-primary-cache-location-from-location
1195 cache (line-location from-line) from-cache))))
1196 (declare (fixnum primary))
1197 (multiple-value-bind (free emptyp)
1198 (find-free-cache-line primary cache)
1199 (when (or forcep emptyp)
1201 (push (cons (line-wrappers free) (line-value free))
1202 (cache-overflow cache)))
1203 ;;(transfer-line from-cache-vector from-line cache-vector free)
1204 (let ((from-cache-vector (cache-vector from-cache))
1205 (to-cache-vector (vector))
1207 (declare (fixnum to-line))
1208 (if (line-reserved-p to-line)
1209 (error "transferring something into a reserved cache line")
1210 (let ((from-loc (line-location from-line))
1211 (to-loc (line-location to-line)))
1212 (declare (fixnum from-loc to-loc))
1213 (modify-cache to-cache-vector
1214 (dotimes-fixnum (i (line-size))
1215 (setf (cache-vector-ref to-cache-vector
1217 (cache-vector-ref from-cache-vector
1218 (+ from-loc i)))))))
1219 (maybe-check-cache cache)))))))
1221 ;;; Returns NIL or (values <field> <cache-vector>)
1223 ;;; This is only called when it isn't possible to put the entry in the
1224 ;;; cache the easy way. That is, this function assumes that
1225 ;;; FILL-CACHE-P has been called as returned NIL.
1227 ;;; If this returns NIL, it means that it wasn't possible to find a
1228 ;;; wrapper field for which all of the entries could be put in the
1229 ;;; cache (within the limit).
1230 (defun adjust-cache (cache wrappers value free-old-cache-p)
1231 (with-local-cache-functions (cache)
1232 (let ((ncache (get-cache-from-cache cache (nlines) (field))))
1233 (do ((nfield (cache-field ncache) (next-wrapper-cache-number-index nfield)))
1234 ((null nfield) (free-cache ncache) nil)
1235 (setf (cache-field ncache) nfield)
1236 (labels ((try-one-fill-from-line (line)
1237 (fill-cache-from-cache-p nil ncache cache line))
1238 (try-one-fill (wrappers value)
1239 (fill-cache-p nil ncache wrappers value)))
1240 (if (and (dotimes-fixnum (i (nlines) t)
1241 (when (and (null (line-reserved-p i))
1242 (line-valid-p i wrappers))
1243 (unless (try-one-fill-from-line i) (return nil))))
1244 (dolist (wrappers+value (cache-overflow cache) t)
1245 (unless (try-one-fill (car wrappers+value) (cdr wrappers+value))
1247 (try-one-fill wrappers value))
1248 (progn (when free-old-cache-p (free-cache cache))
1249 (return (maybe-check-cache ncache)))
1250 (flush-cache-vector-internal (cache-vector ncache))))))))
1252 ;;; returns: (values <cache>)
1253 (defun expand-cache (cache wrappers value free-old-cache-p)
1254 ;;(declare (values cache))
1255 (with-local-cache-functions (cache)
1256 (let ((ncache (get-cache-from-cache cache (* (nlines) 2))))
1257 (labels ((do-one-fill-from-line (line)
1258 (unless (fill-cache-from-cache-p nil ncache cache line)
1259 (do-one-fill (line-wrappers line) (line-value line))))
1260 (do-one-fill (wrappers value)
1261 (setq ncache (or (adjust-cache ncache wrappers value t)
1262 (fill-cache-p t ncache wrappers value))))
1263 (try-one-fill (wrappers value)
1264 (fill-cache-p nil ncache wrappers value)))
1265 (dotimes-fixnum (i (nlines))
1266 (when (and (null (line-reserved-p i))
1267 (line-valid-p i wrappers))
1268 (do-one-fill-from-line i)))
1269 (dolist (wrappers+value (cache-overflow cache))
1270 (unless (try-one-fill (car wrappers+value) (cdr wrappers+value))
1271 (do-one-fill (car wrappers+value) (cdr wrappers+value))))
1272 (unless (try-one-fill wrappers value)
1273 (do-one-fill wrappers value))
1274 (when free-old-cache-p (free-cache cache))
1275 (maybe-check-cache ncache)))))
1277 ;;; This is the heart of the cache filling mechanism. It implements
1278 ;;; the decisions about where entries are placed.
1280 ;;; Find a line in the cache at which a new entry can be inserted.
1283 ;;; <empty?> is <line> in fact empty?
1284 (defun find-free-cache-line (primary cache &optional wrappers)
1285 ;;(declare (values line empty?))
1286 (declare (fixnum primary))
1287 (with-local-cache-functions (cache)
1288 (when (line-reserved-p primary) (setq primary (next-line primary)))
1289 (let ((limit (funcall (limit-fn) (nlines)))
1292 (p primary) (s primary))
1293 (declare (fixnum p s limit))
1296 ;; Try to find a free line starting at <s>. <p> is the
1297 ;; primary line of the entry we are finding a free
1298 ;; line for, it is used to compute the separations.
1299 (do* ((line s (next-line line))
1300 (nsep (line-separation p s) (1+ nsep)))
1302 (declare (fixnum line nsep))
1303 (when (null (line-valid-p line wrappers)) ;If this line is empty or
1304 (push line lines) ;invalid, just use it.
1305 (return-from find-free))
1306 (when (and wrappedp (>= line primary))
1307 ;; have gone all the way around the cache, time to quit
1308 (return-from find-free-cache-line (values primary nil)))
1309 (let ((osep (line-separation (line-primary line) line)))
1310 (when (>= osep limit)
1311 (return-from find-free-cache-line (values primary nil)))
1312 (when (cond ((= nsep limit) t)
1313 ((= nsep osep) (zerop (random 2)))
1316 ;; See whether we can displace what is in this line so that we
1317 ;; can use the line.
1318 (when (= line (the fixnum (1- (nlines)))) (setq wrappedp t))
1319 (setq p (line-primary line))
1320 (setq s (next-line line))
1323 (when (= line (the fixnum (1- (nlines)))) (setq wrappedp t)))))
1324 ;; Do all the displacing.
1326 (when (null (cdr lines)) (return nil))
1327 (let ((dline (pop lines))
1329 (declare (fixnum dline line))
1330 ;;Copy from line to dline (dline is known to be free).
1331 (let ((from-loc (line-location line))
1332 (to-loc (line-location dline))
1333 (cache-vector (vector)))
1334 (declare (fixnum from-loc to-loc) (simple-vector cache-vector))
1335 (modify-cache cache-vector
1336 (dotimes-fixnum (i (line-size))
1337 (setf (cache-vector-ref cache-vector
1339 (cache-vector-ref cache-vector
1341 (setf (cache-vector-ref cache-vector
1344 (values (car lines) t))))
1346 (defun default-limit-fn (nlines)
1352 (defvar *empty-cache* (make-cache)) ; for defstruct slot initial value forms
1354 ;;; Pre-allocate generic function caches. The hope is that this will
1355 ;;; put them nicely together in memory, and that that may be a win. Of
1356 ;;; course the first GC copy will probably blow that out, this really
1357 ;;; wants to be wrapped in something that declares the area static.
1359 ;;; This preallocation only creates about 25% more caches than PCL
1360 ;;; itself uses. Some ports may want to preallocate some more of
1363 ;;; KLUDGE: Isn't something very similar going on in precom1.lisp? Do
1364 ;;; we need it both here and there? Why? -- WHN 19991203
1365 (eval-when (:load-toplevel)
1366 (dolist (n-size '((1 513)(3 257)(3 129)(14 128)(6 65)(2 64)(7 33)(16 32)
1367 (16 17)(32 16)(64 9)(64 8)(6 5)(128 4)(35 2)))
1368 (let ((n (car n-size))
1369 (size (cadr n-size)))
1370 (mapcar #'free-cache-vector
1371 (mapcar #'get-cache-vector
1372 (make-list n :initial-element size))))))
1374 (defun caches-to-allocate ()
1375 (sort (let ((l nil))
1376 (maphash #'(lambda (size entry)
1377 (push (list (car entry) size) l))
1378 sb-pcl::*free-caches*)