\f
;;;; utilities
-;;; Without the locking the next vector can get cyclic causing
-;;; looping in a WITHOUT-GCING form, SHRINK-VECTOR can corrupt memory
-;;; and who knows what else.
-;;;
-;;; WITHOUT-GCING implies WITHOUT-INTERRUPTS.
-(defmacro with-spinlock-and-without-gcing ((spinlock) block &body body)
- #!-sb-thread
- (declare (ignore spinlock))
- `(without-gcing
- (unwind-protect
- (progn
- #!+sb-thread
- (sb!thread::get-spinlock ,spinlock)
- (block ,block ,@body))
- #!+sb-thread
- (sb!thread::release-spinlock ,spinlock))))
-
(eval-when (:compile-toplevel :load-toplevel :execute)
(defconstant max-hash sb!xc:most-positive-fixnum))
+;;; Code for detecting concurrent accesses to the same table from
+;;; multiple threads. Only compiled in when the :SB-HASH-TABLE-DEBUG
+;;; feature is enabled. The main reason for the existence of this code
+;;; is to detect thread-unsafe uses of hash-tables in sbcl itself,
+;;; where debugging anythign can be impossible after an important
+;;; internal hash-table has been corrupted. It's plausible that this
+;;; could be useful for some user code too, but the runtime cost is
+;;; really too high to enable it by default.
+(defmacro with-concurrent-access-check (hash-table &body body)
+ (declare (ignorable hash-table))
+ #!-sb-hash-table-debug
+ `(progn ,@body)
+ #!+sb-hash-table-debug
+ (once-only ((hash-table hash-table))
+ `(progn
+ (flet ((body-fun ()
+ ,@body)
+ (error-fun ()
+ ;; Don't signal more errors for this table.
+ (setf (hash-table-concurrent-access-error ,hash-table) nil)
+ (error "Concurrent access to ~A" ,hash-table)))
+ (if (hash-table-concurrent-access-error ,hash-table)
+ (let ((thread (hash-table-accessing-thread ,hash-table)))
+ (unwind-protect
+ (progn
+ (when (and thread
+ (not (eql thread sb!thread::*current-thread*)))
+ (error-fun))
+ (setf (hash-table-accessing-thread ,hash-table)
+ sb!thread::*current-thread*)
+ (body-fun))
+ (unless (eql (hash-table-accessing-thread ,hash-table)
+ sb!thread::*current-thread*)
+ (error-fun))
+ (setf (hash-table-accessing-thread ,hash-table) thread)))
+ (body-fun))))))
+
(deftype hash ()
`(integer 0 ,max-hash))
(t
(eq-hash key))))
-(defun almost-primify (num)
+(defun ceil-power-of-two (num)
(declare (type index num))
- #!+sb-doc
- "Return an almost prime number greater than or equal to NUM."
- (if (= (rem num 2) 0)
- (setq num (+ 1 num)))
- (if (= (rem num 3) 0)
- (setq num (+ 2 num)))
- (if (= (rem num 7) 0)
- (setq num (+ 4 num)))
- num)
+ (ash 1 (integer-length num)))
+
+(declaim (inline index-for-hashing))
+(defun index-for-hashing (index length)
+ (declare (type index index length))
+ ;; We're using power of two tables which obviously are very
+ ;; sensitive to the exact values of the low bits in the hash
+ ;; value. Do a little shuffling of the value to mix the high bits in
+ ;; there too.
+ (logand (1- length)
+ (+ (logxor #b11100101010001011010100111
+ index)
+ (ash index -6)
+ (ash index -15)
+ (ash index -23))))
+
\f
;;;; user-defined hash table tests
(size +min-hash-table-size+)
(rehash-size 1.5)
(rehash-threshold 1)
- (weakness nil))
+ (weakness nil)
+ (synchronized))
#!+sb-doc
"Create and return a new hash table. The keywords are as follows:
:TEST -- Indicates what kind of test to use.
forcing a rehash. Can be any positive number <=1, with density
approaching zero as the threshold approaches 0. Density 1 means an
average of one entry per bucket.
- :WEAKNESS -- IF NIL (the default) it is a normal non-weak hash table.
+ :WEAKNESS -- If NIL (the default) it is a normal non-weak hash table.
If one of :KEY, :VALUE, :KEY-AND-VALUE, :KEY-OR-VALUE it is a weak
hash table.
Depending on the type of weakness the lack of references to the
is :KEY-AND-VALUE and either the key or the value would otherwise be
garbage the entry can be removed. If WEAKNESS is :KEY-OR-VALUE and
both the key and the value would otherwise be garbage the entry can
- be removed."
+ be removed.
+ :SYNCHRONIZED -- If NIL (the default), the hash-table may have
+ multiple concurrent readers, but results are undefined if a
+ thread writes to the hash-table concurrently with another
+ reader or writer. If T, all concurrent accesses are safe, but
+ note that CLHS 3.6 (Traversal Rules and Side Effects) remains
+ in force. See also: SB-EXT:WITH-LOCKED-HASH-TABLE. This keyword
+ argument is experimental, and may change incompatibly or be
+ removed in the future."
(declare (type (or function symbol) test))
(declare (type unsigned-byte size))
(multiple-value-bind (test test-fun hash-fun)
;; Note that this has not yet been audited for
;; correctness. It just seems to work. -- CSR, 2002-11-02
(scaled-size (truncate (/ (float size+1) rehash-threshold)))
- (length (almost-primify (max scaled-size
- (1+ +min-hash-table-size+))))
+ (length (ceil-power-of-two (max scaled-size
+ (1+ +min-hash-table-size+))))
(index-vector (make-array length
:element-type
'(unsigned-byte #.sb!vm:n-word-bits)
:element-type '(unsigned-byte
#.sb!vm:n-word-bits)
:initial-element +magic-hash-vector-value+))
- :spinlock (sb!thread::make-spinlock))))
+ :synchronized-p synchronized)))
(declare (type index size+1 scaled-size length))
;; Set up the free list, all free. These lists are 0 terminated.
(do ((i 1 (1+ i)))
(setf (aref next-vector i) (1+ i)))
(setf (aref next-vector size) 0)
(setf (hash-table-next-free-kv table) 1)
- (setf (hash-table-needing-rehash table) 0)
(setf (aref kv-vector 0) table)
table)))
(setf (fdocumentation 'hash-table-weakness 'function)
"Return the WEAKNESS of HASH-TABLE which is one of NIL, :KEY,
:VALUE, :KEY-AND-VALUE, :KEY-OR-VALUE.")
+
+;;; Called when we detect circular chains in a hash-table.
+(defun signal-corrupt-hash-table (hash-table)
+ (error "Corrupt NEXT-chain in ~A. This is probably caused by ~
+multiple threads accessing the same hash-table without locking."
+ hash-table))
+
\f
;;;; accessing functions
;;; rehash-size.
(defun rehash (table)
(declare (type hash-table table))
+ (aver *gc-inhibit*)
(let* ((old-kv-vector (hash-table-table table))
(old-next-vector (hash-table-next-vector table))
(old-hash-vector (hash-table-hash-vector table))
(old-size (length old-next-vector))
(new-size
- (let ((rehash-size (hash-table-rehash-size table)))
- (etypecase rehash-size
- (fixnum
- (+ rehash-size old-size))
- (float
- (the index (truncate (* rehash-size old-size)))))))
+ (ceil-power-of-two
+ (let ((rehash-size (hash-table-rehash-size table)))
+ (etypecase rehash-size
+ (fixnum
+ (+ rehash-size old-size))
+ (float
+ (the index (truncate (* rehash-size old-size))))))))
(new-kv-vector (make-array (* 2 new-size)
:initial-element +empty-ht-slot+))
(new-next-vector
(make-array new-size
:element-type '(unsigned-byte #.sb!vm:n-word-bits)
:initial-element +magic-hash-vector-value+)))
- (old-index-vector (hash-table-index-vector table))
- (new-length (almost-primify
- (truncate (/ (float new-size)
- (hash-table-rehash-threshold table)))))
+ (new-length new-size)
(new-index-vector
(make-array new-length
:element-type '(unsigned-byte #.sb!vm:n-word-bits)
(setf (aref new-hash-vector i) (aref old-hash-vector i))))
(setf (hash-table-next-free-kv table) 0)
- (setf (hash-table-needing-rehash table) 0)
;; Rehash all the entries; last to first so that after the pushes
;; the chains are first to last.
(do ((i (1- new-size) (1- i)))
+magic-hash-vector-value+)))
;; Can use the existing hash value (not EQ based)
(let* ((hashing (aref new-hash-vector i))
- (index (rem hashing new-length))
+ (index (index-for-hashing hashing new-length))
(next (aref new-index-vector index)))
(declare (type index index)
(type hash hashing))
(set-header-data new-kv-vector
sb!vm:vector-valid-hashing-subtype)
(let* ((hashing (pointer-hash key))
- (index (rem hashing new-length))
+ (index (index-for-hashing hashing new-length))
(next (aref new-index-vector index)))
(declare (type index index)
(type hash hashing))
(setf (hash-table-index-vector table) new-index-vector)
(setf (hash-table-next-vector table) new-next-vector)
(setf (hash-table-hash-vector table) new-hash-vector)
- ;; Shrink the old vectors to 0 size to help the conservative GC.
- (%shrink-vector old-kv-vector 0)
- (%shrink-vector old-index-vector 0)
- (%shrink-vector old-next-vector 0)
- (when old-hash-vector
- (%shrink-vector old-hash-vector 0))
- (setf (hash-table-rehash-trigger table) new-size))
+ ;; Fill the old kv-vector with 0 to help the conservative GC. Even
+ ;; if nothing else were zeroed, it's important to clear the
+ ;; special first cells in old-kv-vector.
+ (fill old-kv-vector 0)
+ (setf (hash-table-rehash-trigger table) new-size)
+ (setf (hash-table-needs-rehash-p table) nil))
(values))
;;; Use the same size as before, re-using the vectors.
(defun rehash-without-growing (table)
(declare (type hash-table table))
+ (aver *gc-inhibit*)
(let* ((kv-vector (hash-table-table table))
(next-vector (hash-table-next-vector table))
(hash-vector (hash-table-hash-vector table))
;; Rehash all the entries.
(setf (hash-table-next-free-kv table) 0)
- (setf (hash-table-needing-rehash table) 0)
(dotimes (i size)
(setf (aref next-vector i) 0))
(dotimes (i length)
+magic-hash-vector-value+)))
;; Can use the existing hash value (not EQ based)
(let* ((hashing (aref hash-vector i))
- (index (rem hashing length))
+ (index (index-for-hashing hashing length))
(next (aref index-vector index)))
(declare (type index index))
;; Push this slot into the next chain.
;; Enable GC tricks.
(set-header-data kv-vector sb!vm:vector-valid-hashing-subtype)
(let* ((hashing (pointer-hash key))
- (index (rem hashing length))
+ (index (index-for-hashing hashing length))
(next (aref index-vector index)))
(declare (type index index)
(type hash hashing))
;; Push this slot into the next chain.
(setf (aref next-vector i) next)
(setf (aref index-vector index) i)))))))
+ ;; Clear the rehash bit only at the very end, otherwise another thread
+ ;; might see a partially rehashed table as a normal one.
+ (setf (hash-table-needs-rehash-p table) nil)
(values))
-(defun flush-needing-rehash (table)
- (let* ((kv-vector (hash-table-table table))
- (index-vector (hash-table-index-vector table))
- (next-vector (hash-table-next-vector table))
- (length (length index-vector)))
- (do ((next (hash-table-needing-rehash table)))
- ((zerop next))
- (declare (type index/2 next))
- (let* ((key (aref kv-vector (* 2 next)))
- (hashing (pointer-hash key))
- (index (rem hashing length))
- (temp (aref next-vector next)))
- (setf (aref next-vector next) (aref index-vector index))
- (setf (aref index-vector index) next)
- (setf next temp))))
- (setf (hash-table-needing-rehash table) 0)
- (values))
+(declaim (inline maybe-rehash))
+(defun maybe-rehash (hash-table ensure-free-slot-p)
+ (when (hash-table-weakness hash-table)
+ (aver *gc-inhibit*))
+ (flet ((rehash-p ()
+ (and ensure-free-slot-p
+ (zerop (hash-table-next-free-kv hash-table))))
+ (rehash-without-growing-p ()
+ (hash-table-needs-rehash-p hash-table)))
+ (declare (inline rehash-p rehash-without-growing-p))
+ (cond ((rehash-p)
+ ;; Use recursive spinlocks since for weak tables the
+ ;; spinlock has already been acquired. GC must be inhibited
+ ;; to prevent the GC from seeing a rehash in progress.
+ (sb!thread::with-recursive-system-spinlock
+ ((hash-table-spinlock hash-table) :without-gcing t)
+ ;; Repeat the condition inside the lock to ensure that if
+ ;; two reader threads enter MAYBE-REHASH at the same time
+ ;; only one rehash is performed.
+ (when (rehash-p)
+ (rehash hash-table))))
+ ((rehash-without-growing-p)
+ (sb!thread::with-recursive-system-spinlock
+ ((hash-table-spinlock hash-table) :without-gcing t)
+ (when (rehash-without-growing-p)
+ (rehash-without-growing hash-table)))))))
+
+(declaim (inline update-hash-table-cache))
+(defun update-hash-table-cache (hash-table index)
+ (unless (hash-table-weakness hash-table)
+ (setf (hash-table-cache hash-table) index)))
+
+(defmacro with-hash-table-locks ((hash-table
+ &key inline pin
+ (synchronized `(hash-table-synchronized-p ,hash-table)))
+ &body body)
+ (with-unique-names (body-fun)
+ `(with-concurrent-access-check ,hash-table
+ (flet ((,body-fun ()
+ (locally (declare (inline ,@inline))
+ ,@body)))
+ (if (hash-table-weakness ,hash-table)
+ (sb!thread::with-recursive-system-spinlock
+ ((hash-table-spinlock ,hash-table) :without-gcing t)
+ (,body-fun))
+ (with-pinned-objects ,pin
+ (if ,synchronized
+ ;; We use a "system" spinlock here because it is very
+ ;; slightly faster, as it doesn't re-enable interrupts.
+ (sb!thread::with-recursive-system-spinlock
+ ((hash-table-spinlock ,hash-table))
+ (,body-fun))
+ (,body-fun))))))))
(defun gethash (key hash-table &optional default)
#!+sb-doc
- "Finds the entry in HASH-TABLE whose key is KEY and returns the associated
- value and T as multiple values, or returns DEFAULT and NIL if there is no
- such entry. Entries can be added using SETF."
+ "Finds the entry in HASH-TABLE whose key is KEY and returns the
+associated value and T as multiple values, or returns DEFAULT and NIL
+if there is no such entry. Entries can be added using SETF."
(declare (type hash-table hash-table)
(values t (member t nil)))
(gethash3 key hash-table default))
-(defun gethash2 (key hash-table)
- #!+sb-doc
- "Two argument version of GETHASH"
+(declaim (maybe-inline %gethash3))
+(defun %gethash3 (key hash-table default)
(declare (type hash-table hash-table)
+ (optimize speed)
(values t (member t nil)))
- (gethash3 key hash-table nil))
+ (tagbody
+ start
+ (let ((start-epoch sb!kernel::*gc-epoch*))
+ (macrolet ((result (value foundp)
+ ;; When the table has multiple concurrent readers,
+ ;; it's possible that there was a GC after this
+ ;; thread called MAYBE-REHASH from %GETHASH3, and
+ ;; some other thread then rehashed the table. If
+ ;; this happens, we might not find the key even if
+ ;; it's in the table. To protect against this,
+ ;; redo the lookup if the GC epoch counter has changed.
+ ;; -- JES, 2007-09-30
+ `(if (and (not ,foundp)
+ (not (eql start-epoch sb!kernel::*gc-epoch*)))
+ (go start)
+ (return-from %gethash3 (values ,value ,foundp))))
+ (overflow ()
+ ;; The next-vector chain is circular. This is caused
+ ;; caused by thread-unsafe mutations of the table.
+ `(signal-corrupt-hash-table hash-table)))
+ (maybe-rehash hash-table nil)
+ ;; Note that it's OK for a GC + a REHASH-WITHOUT-GROWING to
+ ;; be triggered by another thread after this point, since the
+ ;; GC epoch check will catch it.
+ (let ((cache (hash-table-cache hash-table))
+ (table (hash-table-table hash-table)))
+ ;; First check the cache. Use EQ here for speed.
+ (if (and cache
+ (< cache (length table))
+ (eq (aref table cache) key))
+ (let ((value (aref table (1+ cache))))
+ (result value t))
+ ;; Search for key in the hash table.
+ (multiple-value-bind (hashing eq-based)
+ (funcall (hash-table-hash-fun hash-table) key)
+ (declare (type hash hashing))
+ (let* ((index-vector (hash-table-index-vector hash-table))
+ (length (length index-vector))
+ (index (index-for-hashing hashing length))
+ (next (aref index-vector index))
+ (next-vector (hash-table-next-vector hash-table))
+ (hash-vector (hash-table-hash-vector hash-table))
+ (test-fun (hash-table-test-fun hash-table)))
+ (declare (type index index))
+ ;; Search next-vector chain for a matching key.
+ (if (or eq-based (not hash-vector))
+ (do ((next next (aref next-vector next))
+ (i 0 (1+ i)))
+ ((zerop next) (result default nil))
+ (declare (type index/2 next i))
+ (when (> i length)
+ (overflow))
+ (when (eq key (aref table (* 2 next)))
+ (update-hash-table-cache hash-table (* 2 next))
+ (let ((value (aref table (1+ (* 2 next)))))
+ (result value t))))
+ (do ((next next (aref next-vector next))
+ (i 0 (1+ i)))
+ ((zerop next) (result default nil))
+ (declare (type index/2 next i))
+ (when (> i length)
+ (overflow))
+ (when (and (= hashing (aref hash-vector next))
+ (funcall test-fun key
+ (aref table (* 2 next))))
+ ;; Found.
+ (update-hash-table-cache hash-table (* 2 next))
+ (let ((value (aref table (1+ (* 2 next)))))
+ (result value t)))))))))))))
(defun gethash3 (key hash-table default)
- #!+sb-doc
"Three argument version of GETHASH"
- (declare (type hash-table hash-table)
- (values t (member t nil)))
- (with-spinlock-and-without-gcing ((hash-table-spinlock hash-table))
- gethash3
- (cond ((= (get-header-data (hash-table-table hash-table))
- sb!vm:vector-must-rehash-subtype)
- (rehash-without-growing hash-table))
- ((not (zerop (hash-table-needing-rehash hash-table)))
- (flush-needing-rehash hash-table)))
-
- ;; First check the cache. Use EQ here for speed.
- (let ((cache (hash-table-cache hash-table))
- (table (hash-table-table hash-table)))
-
- (if (and cache (< cache (length table)) (eq (aref table cache) key))
- (values (aref table (1+ cache)) t)
-
- ;; Search for key in the hash table.
- (multiple-value-bind (hashing eq-based)
- (funcall (hash-table-hash-fun hash-table) key)
- (declare (type hash hashing))
- (let* ((index-vector (hash-table-index-vector hash-table))
- (length (length index-vector))
- (index (rem hashing length))
- (next (aref index-vector index))
- (next-vector (hash-table-next-vector hash-table))
- (hash-vector (hash-table-hash-vector hash-table))
- (test-fun (hash-table-test-fun hash-table)))
- (declare (type index index))
- ;; Search next-vector chain for a matching key.
- (if (or eq-based (not hash-vector))
- (do ((next next (aref next-vector next)))
- ((zerop next) (values default nil))
- (declare (type index/2 next))
- (when (eq key (aref table (* 2 next)))
- (setf (hash-table-cache hash-table) (* 2 next))
- (return (values (aref table (1+ (* 2 next))) t))))
- (do ((next next (aref next-vector next)))
- ((zerop next) (values default nil))
- (declare (type index/2 next))
- (when (and (= hashing (aref hash-vector next))
- (funcall test-fun key (aref table (* 2 next))))
- ;; Found.
- (setf (hash-table-cache hash-table) (* 2 next))
- (return (values (aref table (1+ (* 2 next))) t)))))))))))
+ (declare (type hash-table hash-table))
+ (with-hash-table-locks (hash-table :inline (%gethash3) :pin (key))
+ (%gethash3 key hash-table default)))
;;; so people can call #'(SETF GETHASH)
(defun (setf gethash) (new-value key table &optional default)
(declare (ignore default))
(%puthash key table new-value))
+(declaim (maybe-inline %%puthash))
+(defun %%puthash (key hash-table value)
+ (declare (optimize speed))
+ ;; We need to rehash here so that a current key can be found if it
+ ;; exists. Check that there is room for one more entry. May not be
+ ;; needed if the key is already present.
+ (maybe-rehash hash-table t)
+ ;; Search for key in the hash table.
+ (multiple-value-bind (hashing eq-based)
+ (funcall (hash-table-hash-fun hash-table) key)
+ (declare (type hash hashing))
+ (let* ((index-vector (hash-table-index-vector hash-table))
+ (length (length index-vector))
+ (index (index-for-hashing hashing length))
+ (next (aref index-vector index))
+ (kv-vector (hash-table-table hash-table))
+ (next-vector (hash-table-next-vector hash-table))
+ (hash-vector (hash-table-hash-vector hash-table))
+ (test-fun (hash-table-test-fun hash-table)))
+ (declare (type index index next))
+ (when (hash-table-weakness hash-table)
+ (set-header-data kv-vector sb!vm:vector-valid-hashing-subtype))
+ (cond ((or eq-based (not hash-vector))
+ (when eq-based
+ (set-header-data kv-vector
+ sb!vm:vector-valid-hashing-subtype))
+ ;; Search next-vector chain for a matching key.
+ (do ((next next (aref next-vector next))
+ (i 0 (1+ i)))
+ ((zerop next))
+ (declare (type index/2 next i))
+ (when (> i length)
+ (signal-corrupt-hash-table hash-table))
+ (when (eq key (aref kv-vector (* 2 next)))
+ ;; Found, just replace the value.
+ (update-hash-table-cache hash-table (* 2 next))
+ (setf (aref kv-vector (1+ (* 2 next))) value)
+ (return-from %%puthash value))))
+ (t
+ ;; Search next-vector chain for a matching key.
+ (do ((next next (aref next-vector next))
+ (i 0 (1+ i)))
+ ((zerop next))
+ (declare (type index/2 next i))
+ (when (> i length)
+ (signal-corrupt-hash-table hash-table))
+ (when (and (= hashing (aref hash-vector next))
+ (funcall test-fun key
+ (aref kv-vector (* 2 next))))
+ ;; Found, just replace the value.
+ (update-hash-table-cache hash-table (* 2 next))
+ (setf (aref kv-vector (1+ (* 2 next))) value)
+ (return-from %%puthash value)))))
+ ;; Pop a KV slot off the free list
+ (let ((free-kv-slot (hash-table-next-free-kv hash-table)))
+ (declare (type index/2 free-kv-slot))
+ ;; Double-check for overflow.
+ (aver (not (zerop free-kv-slot)))
+ (setf (hash-table-next-free-kv hash-table)
+ (aref next-vector free-kv-slot))
+ (incf (hash-table-number-entries hash-table))
+ (update-hash-table-cache hash-table (* 2 free-kv-slot))
+ (setf (aref kv-vector (* 2 free-kv-slot)) key)
+ (setf (aref kv-vector (1+ (* 2 free-kv-slot))) value)
+ ;; Setup the hash-vector if necessary.
+ (when hash-vector
+ (if (not eq-based)
+ (setf (aref hash-vector free-kv-slot) hashing)
+ (aver (= (aref hash-vector free-kv-slot)
+ +magic-hash-vector-value+))))
+ ;; Push this slot into the next chain.
+ (setf (aref next-vector free-kv-slot) next)
+ (setf (aref index-vector index) free-kv-slot)))
+ value))
+
(defun %puthash (key hash-table value)
(declare (type hash-table hash-table))
(aver (hash-table-index-vector hash-table))
- (with-spinlock-and-without-gcing ((hash-table-spinlock hash-table))
- %puthash
- ;; We need to rehash here so that a current key can be found if it
- ;; exists. Check that there is room for one more entry. May not be
- ;; needed if the key is already present.
- (cond ((zerop (hash-table-next-free-kv hash-table))
- (rehash hash-table))
- ((= (get-header-data (hash-table-table hash-table))
- sb!vm:vector-must-rehash-subtype)
- (rehash-without-growing hash-table))
- ((not (zerop (hash-table-needing-rehash hash-table)))
- (flush-needing-rehash hash-table)))
-
- (let ((cache (hash-table-cache hash-table))
- (kv-vector (hash-table-table hash-table)))
-
- ;; Check the cache
- (if (and cache (< cache (length kv-vector))
- (eq (aref kv-vector cache) key))
- ;; If cached, just store here
- (setf (aref kv-vector (1+ cache)) value)
-
- ;; Search for key in the hash table.
- (multiple-value-bind (hashing eq-based)
- (funcall (hash-table-hash-fun hash-table) key)
- (declare (type hash hashing))
- (let* ((index-vector (hash-table-index-vector hash-table))
- (length (length index-vector))
- (index (rem hashing length))
- (next (aref index-vector index))
- (kv-vector (hash-table-table hash-table))
- (next-vector (hash-table-next-vector hash-table))
- (hash-vector (hash-table-hash-vector hash-table))
- (test-fun (hash-table-test-fun hash-table)))
- (declare (type index index next))
- (when (hash-table-weakness hash-table)
- (set-header-data kv-vector sb!vm:vector-valid-hashing-subtype))
- (cond ((or eq-based (not hash-vector))
- (when eq-based
- (set-header-data kv-vector
- sb!vm:vector-valid-hashing-subtype))
-
- ;; Search next-vector chain for a matching key.
- (do ((next next (aref next-vector next)))
- ((zerop next))
- (declare (type index/2 next))
- (when (eq key (aref kv-vector (* 2 next)))
- ;; Found, just replace the value.
- (setf (hash-table-cache hash-table) (* 2 next))
- (setf (aref kv-vector (1+ (* 2 next))) value)
- (return-from %puthash value))))
- (t
- ;; Search next-vector chain for a matching key.
- (do ((next next (aref next-vector next)))
- ((zerop next))
- (declare (type index/2 next))
- (when (and (= hashing (aref hash-vector next))
- (funcall test-fun key
- (aref kv-vector (* 2 next))))
- ;; Found, just replace the value.
- (setf (hash-table-cache hash-table) (* 2 next))
- (setf (aref kv-vector (1+ (* 2 next))) value)
- (return-from %puthash value)))))
-
- ;; Pop a KV slot off the free list
- (let ((free-kv-slot (hash-table-next-free-kv hash-table)))
- (declare (type index/2 free-kv-slot))
- ;; Double-check for overflow.
- (aver (not (zerop free-kv-slot)))
- (setf (hash-table-next-free-kv hash-table)
- (aref next-vector free-kv-slot))
- (incf (hash-table-number-entries hash-table))
-
- (setf (hash-table-cache hash-table) (* 2 free-kv-slot))
- (setf (aref kv-vector (* 2 free-kv-slot)) key)
- (setf (aref kv-vector (1+ (* 2 free-kv-slot))) value)
-
- ;; Setup the hash-vector if necessary.
- (when hash-vector
- (if (not eq-based)
- (setf (aref hash-vector free-kv-slot) hashing)
- (aver (= (aref hash-vector free-kv-slot)
- +magic-hash-vector-value+))))
-
- ;; Push this slot into the next chain.
- (setf (aref next-vector free-kv-slot) next)
- (setf (aref index-vector index) free-kv-slot)))))))
- value)
+ (macrolet ((put-it (lockedp)
+ `(let ((cache (hash-table-cache hash-table))
+ (kv-vector (hash-table-table hash-table)))
+ ;; Check the cache
+ (if (and cache
+ (< cache (length kv-vector))
+ (eq (aref kv-vector cache) key))
+ ;; If cached, just store here
+ (setf (aref kv-vector (1+ cache)) value)
+ ;; Otherwise do things the hard way
+ ,(if lockedp
+ '(%%puthash key hash-table value)
+ '(with-hash-table-locks
+ (hash-table :inline (%%puthash) :pin (key)
+ :synchronized nil)
+ (%%puthash key hash-table value)))))))
+ (if (hash-table-synchronized-p hash-table)
+ (with-hash-table-locks (hash-table :pin (key) :synchronized t)
+ (put-it t))
+ (put-it nil))))
+
+(declaim (maybe-inline %remhash))
+(defun %remhash (key hash-table)
+ ;; We need to rehash here so that a current key can be found if it
+ ;; exists.
+ ;;
+ ;; Note that if a GC happens after MAYBE-REHASH returns and another
+ ;; thread the accesses the table (triggering a rehash), we might not
+ ;; find the key even if it is in the table. But that's ok, since the
+ ;; only concurrent case that we safely allow is multiple readers
+ ;; with no writers.
+ (maybe-rehash hash-table nil)
+ ;; Search for key in the hash table.
+ (multiple-value-bind (hashing eq-based)
+ (funcall (hash-table-hash-fun hash-table) key)
+ (declare (type hash hashing))
+ (let* ((index-vector (hash-table-index-vector hash-table))
+ (length (length index-vector))
+ (index (index-for-hashing hashing length))
+ (next (aref index-vector index))
+ (table (hash-table-table hash-table))
+ (next-vector (hash-table-next-vector hash-table))
+ (hash-vector (hash-table-hash-vector hash-table))
+ (test-fun (hash-table-test-fun hash-table)))
+ (declare (type index index)
+ (type index/2 next))
+ (flet ((clear-slot (chain-vector prior-slot-location slot-location)
+ (declare (type index/2 slot-location))
+ ;; Mark slot as empty.
+ (setf (aref table (* 2 slot-location)) +empty-ht-slot+
+ (aref table (1+ (* 2 slot-location))) +empty-ht-slot+)
+ ;; Update the prior pointer in the chain to skip this.
+ (setf (aref chain-vector prior-slot-location)
+ (aref next-vector slot-location))
+ ;; Push KV slot onto free chain.
+ (setf (aref next-vector slot-location)
+ (hash-table-next-free-kv hash-table))
+ (setf (hash-table-next-free-kv hash-table) slot-location)
+ (when hash-vector
+ (setf (aref hash-vector slot-location)
+ +magic-hash-vector-value+))
+ (decf (hash-table-number-entries hash-table))
+ t))
+ (cond ((zerop next)
+ nil)
+ ((if (or eq-based (not hash-vector))
+ (eq key (aref table (* 2 next)))
+ (and (= hashing (aref hash-vector next))
+ (funcall test-fun key (aref table (* 2 next)))))
+ (clear-slot index-vector index next))
+ ;; Search next-vector chain for a matching key.
+ ((or eq-based (not hash-vector))
+ ;; EQ based
+ (do ((prior next next)
+ (i 0 (1+ i))
+ (next (aref next-vector next) (aref next-vector next)))
+ ((zerop next) nil)
+ (declare (type index next))
+ (when (> i length)
+ (signal-corrupt-hash-table hash-table))
+ (when (eq key (aref table (* 2 next)))
+ (return-from %remhash (clear-slot next-vector prior next)))))
+ (t
+ ;; not EQ based
+ (do ((prior next next)
+ (i 0 (1+ i))
+ (next (aref next-vector next) (aref next-vector next)))
+ ((zerop next) nil)
+ (declare (type index/2 next))
+ (when (> i length)
+ (signal-corrupt-hash-table hash-table))
+ (when (and (= hashing (aref hash-vector next))
+ (funcall test-fun key (aref table (* 2 next))))
+ (return-from %remhash
+ (clear-slot next-vector prior next))))))))))
(defun remhash (key hash-table)
#!+sb-doc
- "Remove the entry in HASH-TABLE associated with KEY. Return T if there
- was such an entry, or NIL if not."
+ "Remove the entry in HASH-TABLE associated with KEY. Return T if
+there was such an entry, or NIL if not."
(declare (type hash-table hash-table)
(values (member t nil)))
- (with-spinlock-and-without-gcing ((hash-table-spinlock hash-table))
- remhash
- ;; We need to rehash here so that a current key can be found if it
- ;; exists.
- (cond ((= (get-header-data (hash-table-table hash-table))
- sb!vm:vector-must-rehash-subtype)
- (rehash-without-growing hash-table))
- ((not (zerop (hash-table-needing-rehash hash-table)))
- (flush-needing-rehash hash-table)))
-
- ;; For now, just clear the cache
- (setf (hash-table-cache hash-table) nil)
-
- ;; Search for key in the hash table.
- (multiple-value-bind (hashing eq-based)
- (funcall (hash-table-hash-fun hash-table) key)
- (declare (type hash hashing))
- (let* ((index-vector (hash-table-index-vector hash-table))
- (length (length index-vector))
- (index (rem hashing length))
- (next (aref index-vector index))
- (table (hash-table-table hash-table))
- (next-vector (hash-table-next-vector hash-table))
- (hash-vector (hash-table-hash-vector hash-table))
- (test-fun (hash-table-test-fun hash-table)))
- (declare (type index index)
- (type index/2 next))
- (flet ((clear-slot (chain-vector prior-slot-location slot-location)
- (declare (type index/2 slot-location))
- ;; Mark slot as empty.
- (setf (aref table (* 2 slot-location)) +empty-ht-slot+
- (aref table (1+ (* 2 slot-location))) +empty-ht-slot+)
- ;; Update the prior pointer in the chain to skip this.
- (setf (aref chain-vector prior-slot-location)
- (aref next-vector slot-location))
- ;; Push KV slot onto free chain.
- (setf (aref next-vector slot-location)
- (hash-table-next-free-kv hash-table))
- (setf (hash-table-next-free-kv hash-table) slot-location)
- (when hash-vector
- (setf (aref hash-vector slot-location)
- +magic-hash-vector-value+))
- (decf (hash-table-number-entries hash-table))
- t))
- (cond ((zerop next)
- nil)
- ((if (or eq-based (not hash-vector))
- (eq key (aref table (* 2 next)))
- (and (= hashing (aref hash-vector next))
- (funcall test-fun key (aref table (* 2 next)))))
- (clear-slot index-vector index next))
- ;; Search next-vector chain for a matching key.
- ((or eq-based (not hash-vector))
- ;; EQ based
- (do ((prior next next)
- (next (aref next-vector next) (aref next-vector next)))
- ((zerop next) nil)
- (declare (type index next))
- (when (eq key (aref table (* 2 next)))
- (return-from remhash (clear-slot next-vector prior next)))))
- (t
- ;; not EQ based
- (do ((prior next next)
- (next (aref next-vector next) (aref next-vector next)))
- ((zerop next) nil)
- (declare (type index/2 next))
- (when (and (= hashing (aref hash-vector next))
- (funcall test-fun key (aref table (* 2 next))))
- (return-from remhash
- (clear-slot next-vector prior next)))))))))))
+ (with-hash-table-locks (hash-table :inline (%remhash) :pin (key))
+ ;; For now, just clear the cache
+ (setf (hash-table-cache hash-table) nil)
+ (%remhash key hash-table)))
(defun clrhash (hash-table)
#!+sb-doc
- "This removes all the entries from HASH-TABLE and returns the hash table
- itself."
- (declare (optimize speed))
- (with-spinlock-and-without-gcing ((hash-table-spinlock hash-table))
- clrhash
+ "This removes all the entries from HASH-TABLE and returns the hash
+table itself."
+ (with-hash-table-locks (hash-table)
(let* ((kv-vector (hash-table-table hash-table))
(next-vector (hash-table-next-vector hash-table))
(hash-vector (hash-table-hash-vector hash-table))
(setf (aref next-vector i) (1+ i)))
(setf (aref next-vector (1- size)) 0)
(setf (hash-table-next-free-kv hash-table) 1)
- (setf (hash-table-needing-rehash hash-table) 0)
;; Clear the index-vector.
(fill index-vector 0)
;; Clear the hash-vector.
(when hash-vector
(fill hash-vector +magic-hash-vector-value+)))
(setf (hash-table-cache hash-table) nil)
- (setf (hash-table-number-entries hash-table) 0))
- hash-table)
+ (setf (hash-table-number-entries hash-table) 0)
+ hash-table))
+
\f
;;;; MAPHASH
(defun maphash (function-designator hash-table)
#!+sb-doc
"For each entry in HASH-TABLE, call the designated two-argument function on
-the key and value of the entry. Return NIL."
+the key and value of the entry. Return NIL.
+
+Consequences are undefined if HASH-TABLE is mutated during the call to
+MAPHASH, except for changing or removing elements corresponding to the
+current key. The applies to all threads, not just the current one --
+even for synchronized hash-tables. If the table may be mutated by
+another thread during iteration, use eg. SB-EXT:WITH-LOCKED-HASH-TABLE
+to protect the MAPHASH call."
;; This essentially duplicates WITH-HASH-TABLE-ITERATOR, so
;; any changes here should be reflected there as well.
(let ((fun (%coerce-callable-to-fun function-designator))
(declare (ignore environment))
(values `(make-hash-table ,@(%hash-table-ctor-args hash-table))
`(%stuff-hash-table ,hash-table ',(%hash-table-alist hash-table))))
+
+\f
projects / sbcl.git / blobdiff