1.0.4.63: Don't zeroize dynamic-extent simple-unboxed-arrays on x86 and x86-64

[sbcl.git] / src / compiler / x86-64 / alloc.lisp

diff --git a/src/compiler/x86-64/alloc.lisp b/src/compiler/x86-64/alloc.lisp
index 76bad49..707a459 100644 (file)
--- a/src/compiler/x86-64/alloc.lisp
+++ b/src/compiler/x86-64/alloc.lisp
@@ -96,7 +96,7 @@
       (storew length result vector-length-slot other-pointer-lowtag))))
 
 (define-vop (allocate-vector-on-stack)
-  (:args (type :scs (unsigned-reg))
+  (:args (type :scs (unsigned-reg immediate))
          (length :scs (any-reg))
          (words :scs (any-reg) :target ecx))
   (:temporary (:sc any-reg :offset ecx-offset :from (:argument 2)) ecx)
@@ -110,23 +110,30 @@
   (:policy :fast-safe)
   (:node-var node)
   (:generator 100
-    (inst lea result (make-ea :byte :base words :disp
-                              (+ (1- (ash 1 n-lowtag-bits))
-                                 (* vector-data-offset n-word-bytes))))
-    (inst and result (lognot lowtag-mask))
-    ;; FIXME: It would be good to check for stack overflow here.
-    (move ecx words)
-    (inst shr ecx n-fixnum-tag-bits)
-    (allocation result result node t)
-    (inst cld)
-    (inst lea res
-          (make-ea :byte :base result :disp (* vector-data-offset n-word-bytes)))
-    (inst lea result (make-ea :byte :base result :disp other-pointer-lowtag))
-    (storew type result 0 other-pointer-lowtag)
-    (storew length result vector-length-slot other-pointer-lowtag)
-    (zeroize zero)
-    (inst rep)
-    (inst stos zero)))
+    (when (sc-is type immediate)
+      (aver (typep (tn-value type) '(unsigned-byte 8))))
+    (let ((unboxed-elements-p (and (sc-is type immediate)
+                                   (/= (tn-value type)
+                                       simple-vector-widetag))))
+      (inst lea result (make-ea :byte :base words :disp
+                                (+ (1- (ash 1 n-lowtag-bits))
+                                   (* vector-data-offset n-word-bytes))))
+      (inst and result (lognot lowtag-mask))
+      ;; FIXME: It would be good to check for stack overflow here.
+      (move ecx words)
+      (inst shr ecx n-fixnum-tag-bits)
+      (allocation result result node t)
+      (unless unboxed-elements-p
+        (inst cld))
+      (inst lea res
+            (make-ea :byte :base result :disp (* vector-data-offset n-word-bytes)))
+      (inst lea result (make-ea :byte :base result :disp other-pointer-lowtag))
+      (storew type result 0 other-pointer-lowtag)
+      (storew length result vector-length-slot other-pointer-lowtag)
+      (unless unboxed-elements-p
+        (zeroize zero)
+        (inst rep)
+        (inst stos zero)))))
 
 (in-package "SB!C")