X-Git-Url: http://repo.macrolet.net/gitweb/?a=blobdiff_plain;ds=sidebyside;f=src%2Fcode%2Fsxhash.lisp;h=c2b70270dc1133011dfc37426d0977e7e55b4c57;hb=235c8f10a2d6b6f34e0122aa2b4ac57c74e3a484;hp=39ccc477573e9284def10432db9bc117413da4b8;hpb=b0a51fec91a2196e95824165dcdb049ff6e3834b;p=sbcl.git

diff --git a/src/code/sxhash.lisp b/src/code/sxhash.lisp
index 39ccc47..c2b7027 100644
--- a/src/code/sxhash.lisp
+++ b/src/code/sxhash.lisp
@@ -18,7 +18,7 @@
 ;;; order to avoid boxing.
 (deftransform sxhash ((x) (single-float))
   '(let* ((val (+ 0.0f0 x))
-	  (bits (single-float-bits val)))
+	  (bits (logand (single-float-bits val) #.(1- (ash 1 32)))))
      (logxor 66194023
 	     (sxhash (the fixnum
 			  (logand most-positive-fixnum
@@ -26,7 +26,7 @@
 					  (ash bits -7))))))))
 (deftransform sxhash ((x) (double-float))
   '(let* ((val (+ 0.0d0 x))
-	  (hi (double-float-high-bits val))
+	  (hi (logand (double-float-high-bits val) #.(1- (ash 1 32))))
 	  (lo (double-float-low-bits val))
 	  (hilo (logxor hi lo)))
      (logxor 475038542
@@ -39,8 +39,8 @@
 ;;; simple.
 (deftransform sxhash ((x) (fixnum))
   '(logand most-positive-fixnum
-	   (logxor (ash (logand x (ash most-positive-fixnum -4)) 4) 
-		   (ash x -1) ; to get sign bit into hash
+	   (logxor (ash (logand x (ash most-positive-fixnum -4)) 4)
+		   (logand (ash x -1) most-positive-fixnum) ; to get sign bit into hash
 		   361475658)))
 
 ;;; SXHASH of SIMPLE-BIT-VECTOR values is defined as a DEFTRANSFORM
@@ -68,7 +68,6 @@
 				'(- sb!vm:n-word-bits
 				    (mod length sb!vm:n-word-bits)))))
 		       (%raw-bits x i))))
-		 (declare (type (unsigned-byte 32) num))
 		 (mix result ,(ecase sb!c:*backend-byte-order*
 				(:little-endian
 				 '(logand num most-positive-fixnum))
@@ -76,7 +75,6 @@
 				 '(ash num (- sb!vm:n-lowtag-bits)))))))
 	   (declare (type index i end-1))
 	   (let ((num (%raw-bits x i)))
-	     (declare (type (unsigned-byte 32) num))
 	     (mixf result ,(ecase sb!c:*backend-byte-order*
 			     (:little-endian
 			      '(logand num most-positive-fixnum))
@@ -105,6 +103,18 @@
 (deftransform sxhash ((x) (symbol))
   (if #+sb-xc-host nil #-sb-xc-host (constant-lvar-p x)
       (sxhash (lvar-value x))
-      '(%sxhash-simple-string (symbol-name x))))
-
-
+      ;; Cache the value of the symbol's sxhash in the symbol-hash slot.
+      '(let ((result (symbol-hash x)))
+	;; 0 marks uninitialized slot. We can't use negative values
+	;; for the uninitialized slots since NIL might be located so
+	;; high in memory on some platforms that its SYMBOL-HASH
+	;; (which contains NIL itself) is a negative fixnum.
+	(if (= 0 result)
+	    (let ((sxhash (%sxhash-simple-string (symbol-name x))))
+	      ;; We could do a (logior sxhash #x10000000) to ensure
+	      ;; that we never store a 0 in the slot. However, it's
+	      ;; such an unlikely event (1/5e8?) that it makes more
+	      ;; sense to optimize for the common case...
+	      (%set-symbol-hash x sxhash)
+	      sxhash)
+	    result))))