X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Ftarget-sxhash.lisp;h=0c4f16ff2bda1b855e40c2a98ecd7e231aa76390;hb=2d3cb6dba6461e98744eca2a1df4f770cea468ca;hp=318e21b1ae8b7f1fab6b33f754c25c9a833524f2;hpb=95a6db7329b91dd90d165dd4057b9b5098d34aa2;p=sbcl.git

diff --git a/src/code/target-sxhash.lisp b/src/code/target-sxhash.lisp
index 318e21b..0c4f16f 100644
--- a/src/code/target-sxhash.lisp
+++ b/src/code/target-sxhash.lisp
@@ -26,9 +26,9 @@
 ;;; desiderata:
 ;;;   * Non-commutativity keeps us from hashing e.g. #(1 5) to the
 ;;;     same value as #(5 1), and ending up in real trouble in some
-;;;     special cases like bit vectors the way that CMUCL SXHASH 18b
+;;;     special cases like bit vectors the way that CMUCL 18b SXHASH 
 ;;;     does. (Under CMUCL 18b, SXHASH of any bit vector is 1..)
-;;;   * We'd like to scatter our hash values the entire possible range
+;;;   * We'd like to scatter our hash values over the entire possible range
 ;;;     of values instead of hashing small or common key values (like
 ;;;     2 and NIL and #\a) to small FIXNUMs the way that the CMUCL 18b
 ;;;     SXHASH function does, again helping to avoid pathologies like
@@ -99,7 +99,7 @@
 ;;;	     (unless (string= (gethash hash ht) string)
 ;;;	       (format t "collision: ~S ~S~%" string (gethash hash ht)))
 ;;;	     (setf (gethash hash ht) string))))
-;;;     (format t "final count=~D~%" (hash-table-count ht)))
+;;;     (format t "final count=~W~%" (hash-table-count ht)))
 
 (defun %sxhash-simple-string (x)
   (declare (optimize speed))
@@ -115,9 +115,12 @@
 ;;;; the SXHASH function
 
 (defun sxhash (x)
+  ;; profiling SXHASH is hard, but we might as well try to make it go
+  ;; fast, in case it is the bottleneck somwhere.  -- CSR, 2003-03-14
+  (declare (optimize speed))
   (labels ((sxhash-number (x)
 	     (etypecase x
-	       (fixnum (sxhash x)) ; through DEFTRANSFORM
+	       (fixnum (sxhash x))	; through DEFTRANSFORM
 	       (integer (sb!bignum:sxhash-bignum x))
 	       (single-float (sxhash x)) ; through DEFTRANSFORM
 	       (double-float (sxhash x)) ; through DEFTRANSFORM
@@ -135,7 +138,7 @@
 	   (sxhash-recurse (x &optional (depthoid +max-hash-depthoid+))
 	     (declare (type index depthoid))
 	     (typecase x
-	       (list
+	       (cons
 		(if (plusp depthoid)
 		    (mix (sxhash-recurse (car x) (1- depthoid))
 			 (sxhash-recurse (cdr x) (1- depthoid)))
@@ -144,23 +147,30 @@
 		(if (typep x 'structure-object)
 		    (logxor 422371266
 			    (sxhash ; through DEFTRANSFORM
-			     (class-name (layout-class (%instance-layout x)))))
-		    309518995))
+			     (classoid-name
+			      (layout-classoid (%instance-layout x)))))
+		    (sxhash-instance x)))
 	       (symbol (sxhash x)) ; through DEFTRANSFORM
-	       (number (sxhash-number x))
 	       (array
 		(typecase x
 		  (simple-string (sxhash x)) ; through DEFTRANSFORM
 		  (string (%sxhash-substring x))
-		  (bit-vector (let ((result 410823708))
-				(declare (type fixnum result))
-				(dotimes (i (min depthoid (length x)))
-				  (mixf result (aref x i)))
-				result))
+		  (simple-bit-vector (sxhash x)) ; through DEFTRANSFORM
+		  (bit-vector
+		   ;; FIXME: It must surely be possible to do better
+		   ;; than this.  The problem is that a non-SIMPLE
+		   ;; BIT-VECTOR could be displaced to another, with a
+		   ;; non-zero offset -- so that significantly more
+		   ;; work needs to be done using the %RAW-BITS
+		   ;; approach.  This will probably do for now.
+		   (sxhash-recurse (copy-seq x) depthoid))
 		  (t (logxor 191020317 (sxhash (array-rank x))))))
 	       (character
 		(logxor 72185131
 			(sxhash (char-code x)))) ; through DEFTRANSFORM
+	       ;; general, inefficient case of NUMBER
+	       (number (sxhash-number x))
+	       (generic-function (sxhash-instance x))
 	       (t 42))))
     (sxhash-recurse x)))
 
@@ -185,7 +195,7 @@
     (array (array-psxhash key depthoid))
     (hash-table (hash-table-psxhash key))
     (structure-object (structure-object-psxhash key depthoid))
-    (list (list-psxhash key depthoid))
+    (cons (list-psxhash key depthoid))
     (number (number-psxhash key))
     (character (sxhash (char-upcase key)))
     (t (sxhash key))))
@@ -238,8 +248,8 @@
   (declare (type (integer 0 #.+max-hash-depthoid+) depthoid))
   (let* ((layout (%instance-layout key)) ; i.e. slot #0
 	 (length (layout-length layout))
-	 (class (layout-class layout))
-	 (name (class-name class))
+	 (classoid (layout-classoid layout))
+	 (name (classoid-name classoid))
 	 (result (mix (sxhash name) (the fixnum 79867))))
     (declare (type fixnum result))
     (dotimes (i (min depthoid (1- length)))
@@ -319,88 +329,3 @@
 		     (mixf result (number-psxhash (realpart key)))
 		     (mixf result (number-psxhash (imagpart key)))
 		     result))))))
-
-;;; SXHASH and PSXHASH should distribute hash values well over the
-;;; space of possible values, so that collisions between the hash values
-;;; of unequal objects should be very uncommon.
-;;;
-;;; FIXME: These tests should be enabled once the rest of the system is
-;;; stable. (For now, I don't want to mess with things like making sure
-;;; that bignums are hashed uniquely.)
-;;;#!+sb-test
-#+nil
-(let* ((test-cases `((0 . 1)
-		     (0 . 1)
-		     (1 . 0)
-		     ((1 . 0) (0 . 0))
-		     ((0 . 1) (0 . 0))
-		     ((0 . 0) (1 . 0))
-		     ((0 . 0) (0 . 1))
-		     #((1 . 0) (0 . 0))
-		     #((0 . 1) (0 . 0))
-		     #((0 . 0) (1 . 0))
-		     #((0 . 0) (0 . 1))
-		     #((1 . 0) (0 . 0))
-		     #((0 1) (0 0))
-		     #((0 0) (1 0))
-		     #((0 0) (0 1))
-		     #(#(1 0) (0 0))
-		     #(#(0 1) (0 0))
-		     #(#(0 0) (1 0))
-		     #(#(0 0) (0 1))
-		     #(#*00 #*10)
-		     #(#(0 0) (0 1.0d0))
-		     #(#(-0.0d0 0) (1.0 0))
-		     ;; KLUDGE: Some multi-dimensional array test cases would
-		     ;; be good here too, but currently SBCL isn't smart enough
-		     ;; to dump them as literals, and I'm too lazy to make
-		     ;; code to create them at run time. -- WHN 20000111
-		     44 44.0 44.0d0
-		     44 44.0 44.0d0
-		     -44 -44.0 -44.0d0
-		     0 0.0 0.0d0
-		     -0 -0.0 -0.0d0
-		     -121 -121.0 -121.0d0
-		     3/4 0.75 0.75d0
-		     -3/4 -0.75 -0.75d0
-		     44.1 44.1d0
-		     45 45.0 45.0d0
-		     ,(expt 2 33) ,(expt 2.0 33) ,(expt 2.0d0 33)
-		     ,(- (expt 1/2 50)) ,(- (expt 0.5 50)) ,(- (expt 0.5d0 50))
-		     ,(- (expt 1/2 50)) ,(- (expt 0.5 50)) ,(- (expt 0.5d0 50))
-		     #c(1.0 2.0) #c(1 2.0) #c(1.5 -3/2) #c(3/2 -3/2) #c(0 1)
-		     #c(1.0 2.0) #c(1 2.0) #c(1.5 -3/2) #c(3/2 -3/2) #c(0 1)
-		     ,(make-hash-table)
-		     ,(make-hash-table :test 'equal)
-		     "abc" "ABC" "aBc" 'abc #(#\a #\b #\c) #(a b c) #("A" b c)
-		     "abcc"
-		     "" #* #() () (()) #(()) (#())
-		     "" #* #() () (()) #(()) (#())
-		     #\x #\X #\*
-		     #\x #\X #\*)))
-  (dolist (i test-cases)
-    (unless (typep (sxhash i) '(and fixnum unsigned-byte))
-      (error "bad SXHASH behavior for ~S" i))
-    (unless (typep (psxhash i) '(and fixnum unsigned-byte))
-      (error "bad PSXHASH behavior for ~S" i))
-    (dolist (j test-cases)
-      (flet ((t->boolean (x) (if x t nil)))
-	;; Note: It's possible that a change to the hashing algorithm could
-	;; leave it correct but still cause this test to bomb by causing an
-	;; unlucky random collision. That's not very likely (since there are
-	;; (EXPT 2 29) possible hash values and only on the order of 100 test
-	;; cases, but it's probably worth checking if you are getting a
-	;; mystifying error from this test.
-	(unless (eq (t->boolean (equal i j))
-		    (t->boolean (= (sxhash i) (sxhash j))))
-	  (error "bad SXHASH behavior for ~S ~S" i j))
-	(unless (eq (t->boolean (equalp i j))
-		    (t->boolean (= (psxhash i) (psxhash j))))
-	  (error "bad PSXHASH behavior for ~S ~S" i j))))))
-
-;;; FIXME: Test that the the hash functions can deal with common cases without
-;;; consing.
-;(defun consless-test ()
-;  (dotimes (j 100000)
-;    (dolist (i '("yo" #(1 2 3) #2A((1 2) (1 2)) (1 2 (3)) 1 1.0 1.0d0))
-;      (psxhash i))))