\f
;;;; utilities
-;; This stuff is performance critical and unwind-protect is too
-;; slow. And 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 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) &body body)
#!-sb-thread
(declare (ignore spinlock))
- `(unwind-protect
- (let ((*gc-inhibit* t))
- #!+sb-thread
- (sb!thread::get-spinlock ,spinlock)
- ,@body)
- #!+sb-thread
- (sb!thread::release-spinlock ,spinlock)
- ;; the test is racy, but it can err only on the overeager side
- (sb!kernel::maybe-handle-pending-gc)))
+ `(without-gcing
+ (unwind-protect
+ (progn
+ #!+sb-thread
+ (sb!thread::get-spinlock ,spinlock)
+ ,@body)
+ #!+sb-thread
+ (sb!thread::release-spinlock ,spinlock))))
(eval-when (:compile-toplevel :load-toplevel :execute)
(defconstant max-hash sb!xc:most-positive-fixnum))
#!-sb-fluid (declaim (inline equal-hash))
(defun equal-hash (key)
(declare (values hash (member t nil)))
- (values (sxhash key) nil))
+ (typecase key
+ ;; For some types the definition of EQUAL implies a special hash
+ ((or string cons number bit-vector pathname)
+ (values (sxhash key) nil))
+ ;; Otherwise use an EQ hash, rather than SXHASH, since the values
+ ;; of SXHASH will be extremely badly distributed due to the
+ ;; requirements of the spec fitting badly with our implementation
+ ;; strategy.
+ (t
+ (eq-hash key))))
#!-sb-fluid (declaim (inline eql-hash))
(defun eql-hash (key)
(defun equalp-hash (key)
(declare (values hash (member t nil)))
- (values (psxhash key) nil))
+ (typecase key
+ ;; Types requiring special treatment. Note that PATHNAME and
+ ;; HASH-TABLE are caught by the STRUCTURE-OBJECT test.
+ ((or array cons number character structure-object)
+ (values (psxhash key) nil))
+ (t
+ (eq-hash key))))
(defun almost-primify (num)
(declare (type index num))
(defconstant +min-hash-table-rehash-threshold+ (float 1/16 1.0))
(defun make-hash-table (&key (test 'eql)
- (size +min-hash-table-size+)
- (rehash-size 1.5)
- (rehash-threshold 1)
- (weak-p nil))
+ (size +min-hash-table-size+)
+ (rehash-size 1.5)
+ (rehash-threshold 1)
+ (weakness nil))
#!+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.
- :WEAK-P -- (This is an extension from CMU CL, not currently supported
- in SBCL 0.6.6, but perhaps supported in a future version.) If T,
- don't keep entries if the key would otherwise be garbage."
+ :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
+ key and the value may allow for removal of the entry. If WEAKNESS
+ is :KEY and the key would otherwise be garbage the entry is eligible
+ for removal from the hash table. Similarly, if WEAKNESS is :VALUE
+ the life of an entry depends on its value's references. If WEAKNESS
+ 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."
(declare (type (or function symbol) test))
(declare (type unsigned-byte size))
- (when weak-p
- (error "stub: unsupported WEAK-P option"))
(multiple-value-bind (test test-fun hash-fun)
(cond ((or (eq test #'eq) (eq test 'eq))
(values 'eq #'eq #'eq-hash))
;; Failing that, I'd like to rename it to
;; *USER-HASH-TABLE-TESTS*.
(dolist (info *hash-table-tests*
- (error "unknown :TEST for MAKE-HASH-TABLE: ~S"
- test))
+ (error "unknown :TEST for MAKE-HASH-TABLE: ~S"
+ test))
(destructuring-bind (test-name test-fun hash-fun) info
(when (or (eq test test-name) (eq test test-fun))
(return (values test-name test-fun hash-fun)))))))
;; boxing.
(rehash-threshold (max +min-hash-table-rehash-threshold+
(float rehash-threshold 1.0)))
- (size+1 (1+ size)) ; The first element is not usable.
+ (size+1 (1+ size)) ; The first element is not usable.
;; KLUDGE: The most natural way of expressing the below is
;; (round (/ (float size+1) rehash-threshold)), and indeed
;; it was expressed like that until 0.7.0. However,
:element-type
'(unsigned-byte #.sb!vm:n-word-bits)
:initial-element 0))
- ;; needs to be the same length as the KV vector
- ;; (FIXME: really? why doesn't the code agree?)
+ ;; Needs to be the half the length of the KV vector to link
+ ;; KV entries - mapped to indeces at 2i and 2i+1 -
+ ;; together.
(next-vector (make-array size+1
:element-type
'(unsigned-byte #.sb!vm:n-word-bits)))
:rehash-threshold rehash-threshold
:rehash-trigger size
:table kv-vector
- :weak-p weak-p
+ :weakness weakness
:index-vector index-vector
:next-vector next-vector
- :hash-vector (unless (eq test 'eq)
- (make-array size+1
- :element-type '(unsigned-byte #.sb!vm:n-word-bits)
- :initial-element +magic-hash-vector-value+))
+ :hash-vector
+ (unless (eq test 'eq)
+ (make-array size+1
+ :element-type '(unsigned-byte
+ #.sb!vm:n-word-bits)
+ :initial-element +magic-hash-vector-value+))
:spinlock (sb!thread::make-spinlock))))
(declare (type index size+1 scaled-size length))
;; Set up the free list, all free. These lists are 0 terminated.
"Return the test HASH-TABLE was created with.")
#!+sb-doc
-(setf (fdocumentation 'hash-table-weak-p 'function)
- "Return T if HASH-TABLE will not keep entries for keys that would
- otherwise be garbage, and NIL if it will.")
+(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.")
\f
;;;; accessing functions
(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 0))
- (new-hash-vector (when old-hash-vector
- (make-array new-size
- :element-type '(unsigned-byte #.sb!vm:n-word-bits)
- :initial-element +magic-hash-vector-value+)))
+ (new-next-vector
+ (make-array new-size
+ :element-type '(unsigned-byte #.sb!vm:n-word-bits)
+ :initial-element 0))
+ (new-hash-vector
+ (when old-hash-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-index-vector (make-array new-length
- :element-type '(unsigned-byte #.sb!vm:n-word-bits)
- :initial-element 0)))
+ (hash-table-rehash-threshold table)))))
+ (new-index-vector
+ (make-array new-length
+ :element-type '(unsigned-byte #.sb!vm:n-word-bits)
+ :initial-element 0)))
(declare (type index new-size new-length old-size))
;; Disable GC tricks on the OLD-KV-VECTOR.
(set-header-data old-kv-vector sb!vm:vector-normal-subtype)
+ ;; Non-empty weak hash tables always need GC support.
+ (when (and (hash-table-weakness table) (plusp (hash-table-count table)))
+ (set-header-data new-kv-vector sb!vm:vector-valid-hashing-subtype))
+
;; FIXME: here and in several other places in the hash table code,
;; loops like this one are used when FILL or REPLACE would be
;; appropriate. why are standard CL functions not used?
;; the chains are first to last.
(do ((i (1- new-size) (1- i)))
((zerop i))
+ (declare (type index/2 i))
(let ((key (aref new-kv-vector (* 2 i)))
(value (aref new-kv-vector (1+ (* 2 i)))))
(cond ((and (eq key +empty-ht-slot+)
(hash-table-next-free-kv table))
(setf (hash-table-next-free-kv table) i))
((and new-hash-vector
- (not (= (aref new-hash-vector i) +magic-hash-vector-value+)))
+ (not (= (aref new-hash-vector 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))
(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)
+ (%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))
+ (%shrink-vector old-hash-vector 0))
(setf (hash-table-rehash-trigger table) new-size))
(values))
(length (length index-vector)))
(declare (type index size length))
- ;; Disable GC tricks, they will be re-enabled during the re-hash
- ;; if necesary.
- (set-header-data kv-vector sb!vm:vector-normal-subtype)
+ ;; Non-empty weak hash tables always need GC support.
+ (unless (and (hash-table-weakness table) (plusp (hash-table-count table)))
+ ;; Disable GC tricks, they will be re-enabled during the re-hash
+ ;; if necessary.
+ (set-header-data kv-vector sb!vm:vector-normal-subtype))
;; Rehash all the entries.
(setf (hash-table-next-free-kv table) 0)
(setf (aref index-vector i) 0))
(do ((i (1- size) (1- i)))
((zerop i))
+ (declare (type index/2 i))
(let ((key (aref kv-vector (* 2 i)))
(value (aref kv-vector (1+ (* 2 i)))))
(cond ((and (eq key +empty-ht-slot+)
;; Slot is empty, push it onto free list.
(setf (aref next-vector i) (hash-table-next-free-kv table))
(setf (hash-table-next-free-kv table) i))
- ((and hash-vector (not (= (aref hash-vector i) +magic-hash-vector-value+)))
+ ((and hash-vector (not (= (aref hash-vector i)
+ +magic-hash-vector-value+)))
;; Can use the existing hash value (not EQ based)
(let* ((hashing (aref hash-vector i))
(index (rem hashing length))
(length (length index-vector)))
(do ((next (hash-table-needing-rehash table)))
((zerop next))
- (declare (type index next))
+ (declare (type index/2 next))
(let* ((key (aref kv-vector (* 2 next)))
(hashing (pointer-hash key))
(index (rem hashing length))
(if (or eq-based (not hash-vector))
(do ((next next (aref next-vector next)))
((zerop next) (values default nil))
- (declare (type index next))
+ (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 next))
+ (declare (type index/2 next))
(when (and (= hashing (aref hash-vector next))
(funcall test-fun key (aref table (* 2 next))))
;; Found.
(kv-vector (hash-table-table hash-table)))
;; Check the cache
- (if (and cache (< cache (length kv-vector)) (eq (aref kv-vector cache) key))
+ (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)
(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))
-
+ (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))
+ (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 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))
;; Search next-vector chain for a matching key.
(do ((next next (aref next-vector next)))
((zerop next))
- (declare (type index next))
+ (declare (type index/2 next))
(when (and (= hashing (aref hash-vector next))
(funcall test-fun key
(aref kv-vector (* 2 next))))
;; 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)
(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))
+ (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+)
(do ((prior next next)
(next (aref next-vector next) (aref next-vector next)))
((zerop next) nil)
- (declare (type index next))
+ (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)))))))))))
+ (return-from remhash
+ (clear-slot next-vector prior next)))))))))))
(defun clrhash (hash-table)
#!+sb-doc
;; Set up the free list, all free.
(do ((i 1 (1+ i)))
((>= i (1- size)))
- (setf (aref next-vector i) (1+ i)))
+ (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)
(declaim (inline 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."
+ "For each entry in HASH-TABLE, call the designated two-argument function on
+the key and value of the entry. Return NIL."
+ ;; 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))
(size (length (hash-table-next-vector hash-table))))
(declare (type function fun))
(do ((i 1 (1+ i)))
((>= i size))
- (declare (type index i))
+ (declare (type index/2 i))
(let* ((kv-vector (hash-table-table hash-table))
(key (aref kv-vector (* 2 i)))
(value (aref kv-vector (1+ (* 2 i)))))
- (unless (and (eq key +empty-ht-slot+)
- (eq value +empty-ht-slot+))
+ ;; We are running without locking or WITHOUT-GCING. For a weak
+ ;; :VALUE hash table it's possible that the GC hit after KEY
+ ;; was read and now the entry is gone. So check if either the
+ ;; key or the value is empty.
+ (unless (or (eq key +empty-ht-slot+)
+ (eq value +empty-ht-slot+))
(funcall fun key value))))))
\f
;;;; methods on HASH-TABLE
;;; Return a list of keyword args and values to use for MAKE-HASH-TABLE
;;; when reconstructing HASH-TABLE.
(defun %hash-table-ctor-args (hash-table)
- (when (hash-table-weak-p hash-table)
- ;; FIXME: This might actually work with no trouble, but as of
- ;; sbcl-0.6.12.10 when this code was written, weak hash tables
- ;; weren't working yet, so I couldn't test it. When weak hash
- ;; tables are supported again, this should be fixed.
- (error "can't dump weak hash tables readably")) ; defensive programming..
`(:test ',(hash-table-test hash-table)
:size ',(hash-table-size hash-table)
:rehash-size ',(hash-table-rehash-size hash-table)
- :rehash-threshold ',(hash-table-rehash-threshold hash-table)))
+ :rehash-threshold ',(hash-table-rehash-threshold hash-table)
+ :weakness ',(hash-table-weakness hash-table)))
;;; Return an association list representing the same data as HASH-TABLE.
(defun %hash-table-alist (hash-table)