X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;f=src%2Fcode%2Ftarget-sxhash.lisp;h=5fb976226b61a9144c08d80930b759adad32b472;hb=073501ed49414d9638cb41c05fb80627529f796d;hp=7f6f7b309547c05cbb0942423bd0e8737bafe2db;hpb=de201aeb12169d0bd377eca4da6116c2797a66ad;p=sbcl.git

diff --git a/src/code/target-sxhash.lisp b/src/code/target-sxhash.lisp
index 7f6f7b3..5fb9762 100644
--- a/src/code/target-sxhash.lisp
+++ b/src/code/target-sxhash.lisp
@@ -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))
@@ -117,7 +117,7 @@
 (defun sxhash (x)
   (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
@@ -145,9 +145,15 @@
 		    (logxor 422371266
 			    (sxhash ; through DEFTRANSFORM
 			     (class-name (layout-class (%instance-layout x)))))
+		    ;; Nice though it might be to return a nontrivial
+		    ;; hash value for other instances (especially
+		    ;; STANDARD-OBJECTs) there seems to be no good way
+		    ;; to do so. We can't even do the CLASS-NAME trick
+		    ;; (as used above for STRUCTURE-OBJECT) because
+		    ;; then CHANGE-CLASS would cause SXHASH values to
+		    ;; change, ouch! -- WHN recording wisdom of CSR
 		    309518995))
 	       (symbol (sxhash x)) ; through DEFTRANSFORM
-	       (number (sxhash-number x))
 	       (array
 		(typecase x
 		  (simple-string (sxhash x)) ; through DEFTRANSFORM
@@ -161,6 +167,8 @@
 	       (character
 		(logxor 72185131
 			(sxhash (char-code x)))) ; through DEFTRANSFORM
+	       ;; general, inefficient case of NUMBER
+	       (number (sxhash-number x))
 	       (t 42))))
     (sxhash-recurse x)))