1 ;;;; that part of the implementation of HASH-TABLE which lives solely
2 ;;;; on the target system, not on the cross-compilation host
4 ;;;; This software is part of the SBCL system. See the README file for
7 ;;;; This software is derived from the CMU CL system, which was
8 ;;;; written at Carnegie Mellon University and released into the
9 ;;;; public domain. The software is in the public domain and is
10 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
11 ;;;; files for more information.
13 (in-package "SB!IMPL")
17 (eval-when (:compile-toplevel
:load-toplevel
:execute
)
18 (defconstant max-hash sb
!xc
:most-positive-fixnum
))
20 ;;; Code for detecting concurrent accesses to the same table from
21 ;;; multiple threads. Only compiled in when the :SB-HASH-TABLE-DEBUG
22 ;;; feature is enabled. The main reason for the existence of this code
23 ;;; is to detect thread-unsafe uses of hash-tables in sbcl itself,
24 ;;; where debugging anythign can be impossible after an important
25 ;;; internal hash-table has been corrupted. It's plausible that this
26 ;;; could be useful for some user code too, but the runtime cost is
27 ;;; really too high to enable it by default.
28 (defmacro with-concurrent-access-check
(hash-table &body body
)
29 (declare (ignorable hash-table
))
30 #!-sb-hash-table-debug
32 #!+sb-hash-table-debug
33 (once-only ((hash-table hash-table
))
38 ;; Don't signal more errors for this table.
39 (setf (hash-table-concurrent-access-error ,hash-table
) nil
)
40 (error "Concurrent access to ~A" ,hash-table
)))
41 (if (hash-table-concurrent-access-error ,hash-table
)
42 (let ((thread (hash-table-accessing-thread ,hash-table
)))
46 (not (eql thread sb
!thread
::*current-thread
*)))
48 (setf (hash-table-accessing-thread ,hash-table
)
49 sb
!thread
::*current-thread
*)
51 (unless (eql (hash-table-accessing-thread ,hash-table
)
52 sb
!thread
::*current-thread
*)
54 (setf (hash-table-accessing-thread ,hash-table
) thread
)))
58 `(integer 0 ,max-hash
))
60 ;;; FIXME: Does this always make a nonnegative FIXNUM? If so, then
61 ;;; explain why. If not (or if the reason it always makes a
62 ;;; nonnegative FIXNUM is only the accident that pointers in supported
63 ;;; architectures happen to be in the lower half of the address
64 ;;; space), then fix it.
65 #!-sb-fluid
(declaim (inline pointer-hash
))
66 (defun pointer-hash (key)
67 (declare (values hash
))
68 (truly-the hash
(%primitive sb
!c
:make-fixnum key
)))
70 #!-sb-fluid
(declaim (inline eq-hash
))
72 (declare (values hash
(member t nil
)))
73 (values (pointer-hash key
)
74 (oddp (get-lisp-obj-address key
))))
76 #!-sb-fluid
(declaim (inline equal-hash
))
77 (defun equal-hash (key)
78 (declare (values hash
(member t nil
)))
80 ;; For some types the definition of EQUAL implies a special hash
81 ((or string cons number bit-vector pathname
)
82 (values (sxhash key
) nil
))
83 ;; Otherwise use an EQ hash, rather than SXHASH, since the values
84 ;; of SXHASH will be extremely badly distributed due to the
85 ;; requirements of the spec fitting badly with our implementation
90 #!-sb-fluid
(declaim (inline eql-hash
))
92 (declare (values hash
(member t nil
)))
97 (defun equalp-hash (key)
98 (declare (values hash
(member t nil
)))
100 ;; Types requiring special treatment. Note that PATHNAME and
101 ;; HASH-TABLE are caught by the STRUCTURE-OBJECT test.
102 ((or array cons number character structure-object
)
103 (values (psxhash key
) nil
))
107 (defun ceil-power-of-two (num)
108 (declare (type index num
))
109 (ash 1 (integer-length num
)))
111 (declaim (inline index-for-hashing
))
112 (defun index-for-hashing (index length
)
113 (declare (type index index length
))
114 ;; We're using power of two tables which obviously are very
115 ;; sensitive to the exact values of the low bits in the hash
116 ;; value. Do a little shuffling of the value to mix the high bits in
119 (+ (logxor #b11100101010001011010100111
126 ;;;; user-defined hash table tests
128 (defvar *hash-table-tests
* nil
)
130 (defun define-hash-table-test (name test-fun hash-fun
)
132 "Define a new kind of hash table test."
133 (declare (type symbol name
)
134 (type function test-fun hash-fun
))
135 (setf *hash-table-tests
*
136 (cons (list name test-fun hash-fun
)
137 (remove name
*hash-table-tests
* :test
#'eq
:key
#'car
)))
140 ;;;; construction and simple accessors
142 (defconstant +min-hash-table-size
+ 16)
143 (defconstant +min-hash-table-rehash-threshold
+ (float 1/16 1.0))
145 (defun make-hash-table (&key
(test 'eql
)
146 (size +min-hash-table-size
+)
151 "Create and return a new hash table. The keywords are as follows:
152 :TEST -- Indicates what kind of test to use.
153 :SIZE -- A hint as to how many elements will be put in this hash
155 :REHASH-SIZE -- Indicates how to expand the table when it fills up.
156 If an integer, add space for that many elements. If a floating
157 point number (which must be greater than 1.0), multiply the size
159 :REHASH-THRESHOLD -- Indicates how dense the table can become before
160 forcing a rehash. Can be any positive number <=1, with density
161 approaching zero as the threshold approaches 0. Density 1 means an
162 average of one entry per bucket.
163 :WEAKNESS -- IF NIL (the default) it is a normal non-weak hash table.
164 If one of :KEY, :VALUE, :KEY-AND-VALUE, :KEY-OR-VALUE it is a weak
166 Depending on the type of weakness the lack of references to the
167 key and the value may allow for removal of the entry. If WEAKNESS
168 is :KEY and the key would otherwise be garbage the entry is eligible
169 for removal from the hash table. Similarly, if WEAKNESS is :VALUE
170 the life of an entry depends on its value's references. If WEAKNESS
171 is :KEY-AND-VALUE and either the key or the value would otherwise be
172 garbage the entry can be removed. If WEAKNESS is :KEY-OR-VALUE and
173 both the key and the value would otherwise be garbage the entry can
175 (declare (type (or function symbol
) test
))
176 (declare (type unsigned-byte size
))
177 (multiple-value-bind (test test-fun hash-fun
)
178 (cond ((or (eq test
#'eq
) (eq test
'eq
))
179 (values 'eq
#'eq
#'eq-hash
))
180 ((or (eq test
#'eql
) (eq test
'eql
))
181 (values 'eql
#'eql
#'eql-hash
))
182 ((or (eq test
#'equal
) (eq test
'equal
))
183 (values 'equal
#'equal
#'equal-hash
))
184 ((or (eq test
#'equalp
) (eq test
'equalp
))
185 (values 'equalp
#'equalp
#'equalp-hash
))
187 ;; FIXME: I'd like to remove *HASH-TABLE-TESTS* stuff.
188 ;; Failing that, I'd like to rename it to
189 ;; *USER-HASH-TABLE-TESTS*.
190 (dolist (info *hash-table-tests
*
191 (error "unknown :TEST for MAKE-HASH-TABLE: ~S"
193 (destructuring-bind (test-name test-fun hash-fun
) info
194 (when (or (eq test test-name
) (eq test test-fun
))
195 (return (values test-name test-fun hash-fun
)))))))
196 (let* ((size (max +min-hash-table-size
+
198 ;; SIZE is just a hint, so if the user asks
199 ;; for a SIZE which'd be too big for us to
200 ;; easily implement, we bump it down.
201 (floor array-dimension-limit
1024))))
202 (rehash-size (if (integerp rehash-size
)
204 (float rehash-size
1.0)))
205 ;; FIXME: Original REHASH-THRESHOLD default should be 1.0,
206 ;; not 1, to make it easier for the compiler to avoid
208 (rehash-threshold (max +min-hash-table-rehash-threshold
+
209 (float rehash-threshold
1.0)))
210 (size+1 (1+ size
)) ; The first element is not usable.
211 ;; KLUDGE: The most natural way of expressing the below is
212 ;; (round (/ (float size+1) rehash-threshold)), and indeed
213 ;; it was expressed like that until 0.7.0. However,
214 ;; MAKE-HASH-TABLE is called very early in cold-init, and
215 ;; the SPARC has no primitive instructions for rounding,
216 ;; but only for truncating; therefore, we fudge this issue
217 ;; a little. The other uses of truncate, below, similarly
218 ;; used to be round. -- CSR, 2002-10-01
220 ;; Note that this has not yet been audited for
221 ;; correctness. It just seems to work. -- CSR, 2002-11-02
222 (scaled-size (truncate (/ (float size
+1) rehash-threshold
)))
223 (length (ceil-power-of-two (max scaled-size
224 (1+ +min-hash-table-size
+))))
225 (index-vector (make-array length
227 '(unsigned-byte #.sb
!vm
:n-word-bits
)
229 ;; Needs to be the half the length of the KV vector to link
230 ;; KV entries - mapped to indeces at 2i and 2i+1 -
232 (next-vector (make-array size
+1
234 '(unsigned-byte #.sb
!vm
:n-word-bits
)))
235 (kv-vector (make-array (* 2 size
+1)
236 :initial-element
+empty-ht-slot
+))
237 (table (%make-hash-table
241 :rehash-size rehash-size
242 :rehash-threshold rehash-threshold
246 :index-vector index-vector
247 :next-vector next-vector
249 (unless (eq test
'eq
)
251 :element-type
'(unsigned-byte
253 :initial-element
+magic-hash-vector-value
+))
254 :spinlock
(sb!thread
::make-spinlock
))))
255 (declare (type index size
+1 scaled-size length
))
256 ;; Set up the free list, all free. These lists are 0 terminated.
259 (setf (aref next-vector i
) (1+ i
)))
260 (setf (aref next-vector size
) 0)
261 (setf (hash-table-next-free-kv table
) 1)
262 (setf (aref kv-vector
0) table
)
265 (defun hash-table-count (hash-table)
267 "Return the number of entries in the given HASH-TABLE."
268 (declare (type hash-table hash-table
)
270 (hash-table-number-entries hash-table
))
273 (setf (fdocumentation 'hash-table-rehash-size
'function
)
274 "Return the rehash-size HASH-TABLE was created with.")
277 (setf (fdocumentation 'hash-table-rehash-threshold
'function
)
278 "Return the rehash-threshold HASH-TABLE was created with.")
280 (defun hash-table-size (hash-table)
282 "Return a size that can be used with MAKE-HASH-TABLE to create a hash
283 table that can hold however many entries HASH-TABLE can hold without
285 (hash-table-rehash-trigger hash-table
))
288 (setf (fdocumentation 'hash-table-test
'function
)
289 "Return the test HASH-TABLE was created with.")
292 (setf (fdocumentation 'hash-table-weakness
'function
)
293 "Return the WEAKNESS of HASH-TABLE which is one of NIL, :KEY,
294 :VALUE, :KEY-AND-VALUE, :KEY-OR-VALUE.")
296 ;;; Called when we detect circular chains in a hash-table.
297 (defun signal-corrupt-hash-table (hash-table)
298 (error "Corrupt NEXT-chain in ~A. This is probably caused by ~
299 multiple threads accessing the same hash-table without locking."
303 ;;;; accessing functions
305 ;;; Make new vectors for the table, extending the table based on the
307 (defun rehash (table)
308 (declare (type hash-table table
))
310 (let* ((old-kv-vector (hash-table-table table
))
311 (old-next-vector (hash-table-next-vector table
))
312 (old-hash-vector (hash-table-hash-vector table
))
313 (old-size (length old-next-vector
))
316 (let ((rehash-size (hash-table-rehash-size table
)))
317 (etypecase rehash-size
319 (+ rehash-size old-size
))
321 (the index
(truncate (* rehash-size old-size
))))))))
322 (new-kv-vector (make-array (* 2 new-size
)
323 :initial-element
+empty-ht-slot
+))
326 :element-type
'(unsigned-byte #.sb
!vm
:n-word-bits
)
329 (when old-hash-vector
331 :element-type
'(unsigned-byte #.sb
!vm
:n-word-bits
)
332 :initial-element
+magic-hash-vector-value
+)))
333 (new-length new-size
)
335 (make-array new-length
336 :element-type
'(unsigned-byte #.sb
!vm
:n-word-bits
)
337 :initial-element
0)))
338 (declare (type index new-size new-length old-size
))
340 ;; Disable GC tricks on the OLD-KV-VECTOR.
341 (set-header-data old-kv-vector sb
!vm
:vector-normal-subtype
)
343 ;; Non-empty weak hash tables always need GC support.
344 (when (and (hash-table-weakness table
) (plusp (hash-table-count table
)))
345 (set-header-data new-kv-vector sb
!vm
:vector-valid-hashing-subtype
))
347 ;; FIXME: here and in several other places in the hash table code,
348 ;; loops like this one are used when FILL or REPLACE would be
349 ;; appropriate. why are standard CL functions not used?
350 ;; Performance issues? General laziness? -- NJF, 2004-03-10
352 ;; Copy over the kv-vector. The element positions should not move
353 ;; in case there are active scans.
354 (dotimes (i (* old-size
2))
355 (declare (type index i
))
356 (setf (aref new-kv-vector i
) (aref old-kv-vector i
)))
358 ;; Copy over the hash-vector.
359 (when old-hash-vector
360 (dotimes (i old-size
)
361 (setf (aref new-hash-vector i
) (aref old-hash-vector i
))))
363 (setf (hash-table-next-free-kv table
) 0)
364 ;; Rehash all the entries; last to first so that after the pushes
365 ;; the chains are first to last.
366 (do ((i (1- new-size
) (1- i
)))
368 (declare (type index
/2 i
))
369 (let ((key (aref new-kv-vector
(* 2 i
)))
370 (value (aref new-kv-vector
(1+ (* 2 i
)))))
371 (cond ((and (eq key
+empty-ht-slot
+)
372 (eq value
+empty-ht-slot
+))
373 ;; Slot is empty, push it onto the free list.
374 (setf (aref new-next-vector i
)
375 (hash-table-next-free-kv table
))
376 (setf (hash-table-next-free-kv table
) i
))
377 ((and new-hash-vector
378 (not (= (aref new-hash-vector i
)
379 +magic-hash-vector-value
+)))
380 ;; Can use the existing hash value (not EQ based)
381 (let* ((hashing (aref new-hash-vector i
))
382 (index (index-for-hashing hashing new-length
))
383 (next (aref new-index-vector index
)))
384 (declare (type index index
)
386 ;; Push this slot into the next chain.
387 (setf (aref new-next-vector i
) next
)
388 (setf (aref new-index-vector index
) i
)))
392 (set-header-data new-kv-vector
393 sb
!vm
:vector-valid-hashing-subtype
)
394 (let* ((hashing (pointer-hash key
))
395 (index (index-for-hashing hashing new-length
))
396 (next (aref new-index-vector index
)))
397 (declare (type index index
)
399 ;; Push this slot onto the next chain.
400 (setf (aref new-next-vector i
) next
)
401 (setf (aref new-index-vector index
) i
))))))
402 (setf (hash-table-table table
) new-kv-vector
)
403 (setf (hash-table-index-vector table
) new-index-vector
)
404 (setf (hash-table-next-vector table
) new-next-vector
)
405 (setf (hash-table-hash-vector table
) new-hash-vector
)
406 ;; Fill the old kv-vector with 0 to help the conservative GC. Even
407 ;; if nothing else were zeroed, it's important to clear the
408 ;; special first cells in old-kv-vector.
409 (fill old-kv-vector
0)
410 (setf (hash-table-rehash-trigger table
) new-size
)
411 (setf (hash-table-needs-rehash-p table
) nil
))
414 ;;; Use the same size as before, re-using the vectors.
415 (defun rehash-without-growing (table)
416 (declare (type hash-table table
))
418 (let* ((kv-vector (hash-table-table table
))
419 (next-vector (hash-table-next-vector table
))
420 (hash-vector (hash-table-hash-vector table
))
421 (size (length next-vector
))
422 (index-vector (hash-table-index-vector table
))
423 (length (length index-vector
)))
424 (declare (type index size length
))
426 ;; Non-empty weak hash tables always need GC support.
427 (unless (and (hash-table-weakness table
) (plusp (hash-table-count table
)))
428 ;; Disable GC tricks, they will be re-enabled during the re-hash
430 (set-header-data kv-vector sb
!vm
:vector-normal-subtype
))
432 ;; Rehash all the entries.
433 (setf (hash-table-next-free-kv table
) 0)
435 (setf (aref next-vector i
) 0))
437 (setf (aref index-vector i
) 0))
438 (do ((i (1- size
) (1- i
)))
440 (declare (type index
/2 i
))
441 (let ((key (aref kv-vector
(* 2 i
)))
442 (value (aref kv-vector
(1+ (* 2 i
)))))
443 (cond ((and (eq key
+empty-ht-slot
+)
444 (eq value
+empty-ht-slot
+))
445 ;; Slot is empty, push it onto free list.
446 (setf (aref next-vector i
) (hash-table-next-free-kv table
))
447 (setf (hash-table-next-free-kv table
) i
))
448 ((and hash-vector
(not (= (aref hash-vector i
)
449 +magic-hash-vector-value
+)))
450 ;; Can use the existing hash value (not EQ based)
451 (let* ((hashing (aref hash-vector i
))
452 (index (index-for-hashing hashing length
))
453 (next (aref index-vector index
)))
454 (declare (type index index
))
455 ;; Push this slot into the next chain.
456 (setf (aref next-vector i
) next
)
457 (setf (aref index-vector index
) i
)))
461 (set-header-data kv-vector sb
!vm
:vector-valid-hashing-subtype
)
462 (let* ((hashing (pointer-hash key
))
463 (index (index-for-hashing hashing length
))
464 (next (aref index-vector index
)))
465 (declare (type index index
)
467 ;; Push this slot into the next chain.
468 (setf (aref next-vector i
) next
)
469 (setf (aref index-vector index
) i
)))))))
470 ;; Clear the rehash bit only at the very end, otherwise another thread
471 ;; might see a partially rehashed table as a normal one.
472 (setf (hash-table-needs-rehash-p table
) nil
)
475 (declaim (inline maybe-rehash
))
476 (defun maybe-rehash (hash-table ensure-free-slot-p
)
477 (when (hash-table-weakness hash-table
)
480 (and ensure-free-slot-p
481 (zerop (hash-table-next-free-kv hash-table
))))
482 (rehash-without-growing-p ()
483 (hash-table-needs-rehash-p hash-table
)))
484 (declare (inline rehash-p rehash-without-growing-p
))
486 ;; Use recursive spinlocks since for weak tables the
487 ;; spinlock has already been acquired. GC must be inhibited
488 ;; to prevent the GC from seeing a rehash in progress.
489 (sb!thread
::with-recursive-system-spinlock
490 ((hash-table-spinlock hash-table
) :without-gcing t
)
491 ;; Repeat the condition inside the lock to ensure that if
492 ;; two reader threads enter MAYBE-REHASH at the same time
493 ;; only one rehash is performed.
495 (rehash hash-table
))))
496 ((rehash-without-growing-p)
497 (sb!thread
::with-recursive-system-spinlock
498 ((hash-table-spinlock hash-table
) :without-gcing t
)
499 (when (rehash-without-growing-p)
500 (rehash-without-growing hash-table
)))))))
502 (declaim (inline update-hash-table-cache
))
503 (defun update-hash-table-cache (hash-table index
)
504 (unless (hash-table-weakness hash-table
)
505 (setf (hash-table-cache hash-table
) index
)))
507 (defmacro with-hash-table-locks
((hash-table inline
&rest pin-objects
)
509 `(with-concurrent-access-check ,hash-table
510 ;; Inhibit GC for the duration of BODY if the GC might mutate the
511 ;; HASH-TABLE in some way (currently true only if the table is
512 ;; weak). We also need to lock the table to ensure that two
513 ;; concurrent writers can't create a cyclical vector that would
514 ;; cause scav_weak_hash_table_chain to loop.
516 ;; Otherwise we can avoid the 2x-3x overhead, and just pin the key.
517 (if (hash-table-weakness ,hash-table
)
518 (sb!thread
::with-recursive-system-spinlock
519 ((hash-table-spinlock hash-table
) :without-gcing t
)
521 (with-pinned-objects ,pin-objects
523 ;; Inline the implementation function on the fast path
524 ;; only. (On the slow path it'll just bloat the
525 ;; generated code with no benefit).
526 (declare (inline ,@inline
))
529 (defun gethash (key hash-table
&optional default
)
531 "Finds the entry in HASH-TABLE whose key is KEY and returns the associated
532 value and T as multiple values, or returns DEFAULT and NIL if there is no
533 such entry. Entries can be added using SETF."
534 (declare (type hash-table hash-table
)
535 (values t
(member t nil
)))
536 (gethash3 key hash-table default
))
538 (declaim (maybe-inline %gethash3
))
539 (defun %gethash3
(key hash-table default
)
540 (declare (type hash-table hash-table
)
542 (values t
(member t nil
)))
545 (let ((start-epoch sb
!kernel
::*gc-epoch
*))
546 (macrolet ((result (value foundp
)
547 ;; When the table has multiple concurrent readers,
548 ;; it's possible that there was a GC after this
549 ;; thread called MAYBE-REHASH from %GETHASH3, and
550 ;; some other thread then rehashed the table. If
551 ;; this happens, we might not find the key even if
552 ;; it's in the table. To protect against this,
553 ;; redo the lookup if the GC epoch counter has changed.
554 ;; -- JES, 2007-09-30
555 `(if (and (not ,foundp
)
556 (not (eql start-epoch sb
!kernel
::*gc-epoch
*)))
558 (return-from %gethash3
(values ,value
,foundp
))))
560 ;; The next-vector chain is circular. This is caused
561 ;; caused by thread-unsafe mutations of the table.
562 `(signal-corrupt-hash-table hash-table
)))
563 (maybe-rehash hash-table nil
)
564 ;; Note that it's OK for a GC + a REHASH-WITHOUT-GROWING to
565 ;; be triggered by another thread after this point, since the
566 ;; GC epoch check will catch it.
567 (let ((cache (hash-table-cache hash-table
))
568 (table (hash-table-table hash-table
)))
569 ;; First check the cache. Use EQ here for speed.
571 (< cache
(length table
))
572 (eq (aref table cache
) key
))
573 (let ((value (aref table
(1+ cache
))))
575 ;; Search for key in the hash table.
576 (multiple-value-bind (hashing eq-based
)
577 (funcall (hash-table-hash-fun hash-table
) key
)
578 (declare (type hash hashing
))
579 (let* ((index-vector (hash-table-index-vector hash-table
))
580 (length (length index-vector
))
581 (index (index-for-hashing hashing length
))
582 (next (aref index-vector index
))
583 (next-vector (hash-table-next-vector hash-table
))
584 (hash-vector (hash-table-hash-vector hash-table
))
585 (test-fun (hash-table-test-fun hash-table
)))
586 (declare (type index index
))
587 ;; Search next-vector chain for a matching key.
588 (if (or eq-based
(not hash-vector
))
589 (do ((next next
(aref next-vector next
))
591 ((zerop next
) (result default nil
))
592 (declare (type index
/2 next i
))
595 (when (eq key
(aref table
(* 2 next
)))
596 (update-hash-table-cache hash-table
(* 2 next
))
597 (let ((value (aref table
(1+ (* 2 next
)))))
599 (do ((next next
(aref next-vector next
))
601 ((zerop next
) (result default nil
))
602 (declare (type index
/2 next i
))
605 (when (and (= hashing
(aref hash-vector next
))
606 (funcall test-fun key
607 (aref table
(* 2 next
))))
609 (update-hash-table-cache hash-table
(* 2 next
))
610 (let ((value (aref table
(1+ (* 2 next
)))))
611 (result value t
)))))))))))))
613 (defun gethash3 (key hash-table default
)
614 "Three argument version of GETHASH"
615 (declare (type hash-table hash-table
))
616 (with-hash-table-locks (hash-table (%gethash3
) key
)
617 (%gethash3 key hash-table default
)))
619 ;;; so people can call #'(SETF GETHASH)
620 (defun (setf gethash
) (new-value key table
&optional default
)
621 (declare (ignore default
))
622 (%puthash key table new-value
))
624 (declaim (maybe-inline %%puthash
))
625 (defun %%puthash
(key hash-table value
)
626 (declare (optimize speed
))
627 ;; We need to rehash here so that a current key can be found if it
628 ;; exists. Check that there is room for one more entry. May not be
629 ;; needed if the key is already present.
630 (maybe-rehash hash-table t
)
631 ;; Search for key in the hash table.
632 (multiple-value-bind (hashing eq-based
)
633 (funcall (hash-table-hash-fun hash-table
) key
)
634 (declare (type hash hashing
))
635 (let* ((index-vector (hash-table-index-vector hash-table
))
636 (length (length index-vector
))
637 (index (index-for-hashing hashing length
))
638 (next (aref index-vector index
))
639 (kv-vector (hash-table-table hash-table
))
640 (next-vector (hash-table-next-vector hash-table
))
641 (hash-vector (hash-table-hash-vector hash-table
))
642 (test-fun (hash-table-test-fun hash-table
)))
643 (declare (type index index next
))
644 (when (hash-table-weakness hash-table
)
645 (set-header-data kv-vector sb
!vm
:vector-valid-hashing-subtype
))
646 (cond ((or eq-based
(not hash-vector
))
648 (set-header-data kv-vector
649 sb
!vm
:vector-valid-hashing-subtype
))
650 ;; Search next-vector chain for a matching key.
651 (do ((next next
(aref next-vector next
))
654 (declare (type index
/2 next i
))
656 (signal-corrupt-hash-table hash-table
))
657 (when (eq key
(aref kv-vector
(* 2 next
)))
658 ;; Found, just replace the value.
659 (update-hash-table-cache hash-table
(* 2 next
))
660 (setf (aref kv-vector
(1+ (* 2 next
))) value
)
661 (return-from %%puthash value
))))
663 ;; Search next-vector chain for a matching key.
664 (do ((next next
(aref next-vector next
))
667 (declare (type index
/2 next i
))
669 (signal-corrupt-hash-table hash-table
))
670 (when (and (= hashing
(aref hash-vector next
))
671 (funcall test-fun key
672 (aref kv-vector
(* 2 next
))))
673 ;; Found, just replace the value.
674 (update-hash-table-cache hash-table
(* 2 next
))
675 (setf (aref kv-vector
(1+ (* 2 next
))) value
)
676 (return-from %%puthash value
)))))
677 ;; Pop a KV slot off the free list
678 (let ((free-kv-slot (hash-table-next-free-kv hash-table
)))
679 (declare (type index
/2 free-kv-slot
))
680 ;; Double-check for overflow.
681 (aver (not (zerop free-kv-slot
)))
682 (setf (hash-table-next-free-kv hash-table
)
683 (aref next-vector free-kv-slot
))
684 (incf (hash-table-number-entries hash-table
))
685 (update-hash-table-cache hash-table
(* 2 free-kv-slot
))
686 (setf (aref kv-vector
(* 2 free-kv-slot
)) key
)
687 (setf (aref kv-vector
(1+ (* 2 free-kv-slot
))) value
)
688 ;; Setup the hash-vector if necessary.
691 (setf (aref hash-vector free-kv-slot
) hashing
)
692 (aver (= (aref hash-vector free-kv-slot
)
693 +magic-hash-vector-value
+))))
694 ;; Push this slot into the next chain.
695 (setf (aref next-vector free-kv-slot
) next
)
696 (setf (aref index-vector index
) free-kv-slot
)))
699 (defun %puthash
(key hash-table value
)
700 (declare (type hash-table hash-table
))
701 (aver (hash-table-index-vector hash-table
))
702 (let ((cache (hash-table-cache hash-table
))
703 (kv-vector (hash-table-table hash-table
)))
706 (< cache
(length kv-vector
))
707 (eq (aref kv-vector cache
) key
))
708 ;; If cached, just store here
709 (setf (aref kv-vector
(1+ cache
)) value
)
710 ;; Otherwise do things the hard way
711 (with-hash-table-locks (hash-table (%%puthash
) key
)
712 (%%puthash key hash-table value
)))))
714 (declaim (maybe-inline %remhash
))
715 (defun %remhash
(key hash-table
)
716 ;; We need to rehash here so that a current key can be found if it
719 ;; Note that if a GC happens after MAYBE-REHASH returns and another
720 ;; thread the accesses the table (triggering a rehash), we might not
721 ;; find the key even if it is in the table. But that's ok, since the
722 ;; only concurrent case that we safely allow is multiple readers
724 (maybe-rehash hash-table nil
)
725 ;; Search for key in the hash table.
726 (multiple-value-bind (hashing eq-based
)
727 (funcall (hash-table-hash-fun hash-table
) key
)
728 (declare (type hash hashing
))
729 (let* ((index-vector (hash-table-index-vector hash-table
))
730 (length (length index-vector
))
731 (index (index-for-hashing hashing length
))
732 (next (aref index-vector index
))
733 (table (hash-table-table hash-table
))
734 (next-vector (hash-table-next-vector hash-table
))
735 (hash-vector (hash-table-hash-vector hash-table
))
736 (test-fun (hash-table-test-fun hash-table
)))
737 (declare (type index index
)
739 (flet ((clear-slot (chain-vector prior-slot-location slot-location
)
740 (declare (type index
/2 slot-location
))
741 ;; Mark slot as empty.
742 (setf (aref table
(* 2 slot-location
)) +empty-ht-slot
+
743 (aref table
(1+ (* 2 slot-location
))) +empty-ht-slot
+)
744 ;; Update the prior pointer in the chain to skip this.
745 (setf (aref chain-vector prior-slot-location
)
746 (aref next-vector slot-location
))
747 ;; Push KV slot onto free chain.
748 (setf (aref next-vector slot-location
)
749 (hash-table-next-free-kv hash-table
))
750 (setf (hash-table-next-free-kv hash-table
) slot-location
)
752 (setf (aref hash-vector slot-location
)
753 +magic-hash-vector-value
+))
754 (decf (hash-table-number-entries hash-table
))
758 ((if (or eq-based
(not hash-vector
))
759 (eq key
(aref table
(* 2 next
)))
760 (and (= hashing
(aref hash-vector next
))
761 (funcall test-fun key
(aref table
(* 2 next
)))))
762 (clear-slot index-vector index next
))
763 ;; Search next-vector chain for a matching key.
764 ((or eq-based
(not hash-vector
))
766 (do ((prior next next
)
768 (next (aref next-vector next
) (aref next-vector next
)))
770 (declare (type index next
))
772 (signal-corrupt-hash-table hash-table
))
773 (when (eq key
(aref table
(* 2 next
)))
774 (return-from %remhash
(clear-slot next-vector prior next
)))))
777 (do ((prior next next
)
779 (next (aref next-vector next
) (aref next-vector next
)))
781 (declare (type index
/2 next
))
783 (signal-corrupt-hash-table hash-table
))
784 (when (and (= hashing
(aref hash-vector next
))
785 (funcall test-fun key
(aref table
(* 2 next
))))
786 (return-from %remhash
787 (clear-slot next-vector prior next
))))))))))
789 (defun remhash (key hash-table
)
791 "Remove the entry in HASH-TABLE associated with KEY. Return T if there
792 was such an entry, or NIL if not."
793 (declare (type hash-table hash-table
)
794 (values (member t nil
)))
795 ;; For now, just clear the cache
796 (setf (hash-table-cache hash-table
) nil
)
797 (with-hash-table-locks (hash-table (%remhash
) key
)
798 (%remhash key hash-table
)))
800 (defun clrhash (hash-table)
802 "This removes all the entries from HASH-TABLE and returns the hash table
804 (with-hash-table-locks (hash-table nil
)
805 (let* ((kv-vector (hash-table-table hash-table
))
806 (next-vector (hash-table-next-vector hash-table
))
807 (hash-vector (hash-table-hash-vector hash-table
))
808 (size (length next-vector
))
809 (index-vector (hash-table-index-vector hash-table
)))
810 ;; Disable GC tricks.
811 (set-header-data kv-vector sb
!vm
:vector-normal-subtype
)
812 ;; Mark all slots as empty by setting all keys and values to magic
814 (aver (eq (aref kv-vector
0) hash-table
))
815 (fill kv-vector
+empty-ht-slot
+ :start
2)
816 ;; Set up the free list, all free.
819 (setf (aref next-vector i
) (1+ i
)))
820 (setf (aref next-vector
(1- size
)) 0)
821 (setf (hash-table-next-free-kv hash-table
) 1)
822 ;; Clear the index-vector.
823 (fill index-vector
0)
824 ;; Clear the hash-vector.
826 (fill hash-vector
+magic-hash-vector-value
+)))
827 (setf (hash-table-cache hash-table
) nil
)
828 (setf (hash-table-number-entries hash-table
) 0)
834 ;;; FIXME: This should be made into a compiler transform for two reasons:
835 ;;; 1. It would then be available for compiling the entire system,
836 ;;; not only parts of the system which are defined after DEFUN MAPHASH.
837 ;;; 2. It could be conditional on compilation policy, so that
838 ;;; it could be compiled as a full call instead of an inline
839 ;;; expansion when SPACE>SPEED.
840 (declaim (inline maphash
))
841 (defun maphash (function-designator hash-table
)
843 "For each entry in HASH-TABLE, call the designated two-argument
844 function on the key and value of the entry. Return NIL.
846 Consequences are undefined if HASH-TABLE is mutated during the call to
847 MAPHASH, except for changing or removing elements corresponding to the
849 ;; This essentially duplicates WITH-HASH-TABLE-ITERATOR, so
850 ;; any changes here should be reflected there as well.
851 (let ((fun (%coerce-callable-to-fun function-designator
))
852 (size (length (hash-table-next-vector hash-table
))))
853 (declare (type function fun
))
856 (declare (type index
/2 i
))
857 (let* ((kv-vector (hash-table-table hash-table
))
858 (key (aref kv-vector
(* 2 i
)))
859 (value (aref kv-vector
(1+ (* 2 i
)))))
860 ;; We are running without locking or WITHOUT-GCING. For a weak
861 ;; :VALUE hash table it's possible that the GC hit after KEY
862 ;; was read and now the entry is gone. So check if either the
863 ;; key or the value is empty.
864 (unless (or (eq key
+empty-ht-slot
+)
865 (eq value
+empty-ht-slot
+))
866 (funcall fun key value
))))))
868 ;;;; methods on HASH-TABLE
870 ;;; Return a list of keyword args and values to use for MAKE-HASH-TABLE
871 ;;; when reconstructing HASH-TABLE.
872 (defun %hash-table-ctor-args
(hash-table)
873 `(:test
',(hash-table-test hash-table
)
874 :size
',(hash-table-size hash-table
)
875 :rehash-size
',(hash-table-rehash-size hash-table
)
876 :rehash-threshold
',(hash-table-rehash-threshold hash-table
)
877 :weakness
',(hash-table-weakness hash-table
)))
879 ;;; Return an association list representing the same data as HASH-TABLE.
880 (defun %hash-table-alist
(hash-table)
882 (maphash (lambda (key value
)
883 (push (cons key value
) result
))
887 ;;; Stuff an association list into HASH-TABLE. Return the hash table,
888 ;;; so that we can use this for the *PRINT-READABLY* case in
889 ;;; PRINT-OBJECT (HASH-TABLE T) without having to worry about LET
890 ;;; forms and readable gensyms and stuff.
891 (defun %stuff-hash-table
(hash-table alist
)
893 (setf (gethash (car x
) hash-table
) (cdr x
)))
896 (def!method print-object
((hash-table hash-table
) stream
)
897 (declare (type stream stream
))
898 (cond ((or (not *print-readably
*) (not *read-eval
*))
899 (print-unreadable-object (hash-table stream
:type t
:identity t
)
902 (hash-table-test hash-table
)
903 (hash-table-count hash-table
))))
905 (with-standard-io-syntax
908 `(%stuff-hash-table
(make-hash-table ,@(%hash-table-ctor-args
910 ',(%hash-table-alist hash-table
)))))))
912 (def!method make-load-form
((hash-table hash-table
) &optional environment
)
913 (declare (ignore environment
))
914 (values `(make-hash-table ,@(%hash-table-ctor-args hash-table
))
915 `(%stuff-hash-table
,hash-table
',(%hash-table-alist hash-table
))))