Commit 69ef68ba authored by Alexey Dejneka's avatar Alexey Dejneka
Browse files

0.8.21.50:

        * Changed implementation on ALLOCATE-VECTOR on X86:
        ... two VOPs: A-V-ON-HEAP and A-V-ON-STACK;
        ... choice between them is made with LTN-ANALYZEr;
        ... A-V-ON-STACK always fills vector with zeroes (fixes bug
            reported by Brian Downing).
parent 343ef95f
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+6 −0
Original line number Diff line number Diff line
@@ -218,3 +218,9 @@ SBCL cannot derive upper bound for I and uses generic arithmetic here:

(So the constraint propagator or a possible future SSA-convertor
should know the connection between an NLE and its CLEANUP.)
--------------------------------------------------------------------------------
#27
Initialization of stack-allocated arrays is inefficient: we always
fill the vector with zeroes, even when it is not needed (as for
platforms with conservative GC or for arrays of unboxed objectes) and
is performed later explicitely.
+72 −21
Original line number Diff line number Diff line
@@ -72,24 +72,36 @@
  (:variant t))

;;;; special-purpose inline allocators
(defoptimizer (allocate-vector stack-allocate-result)
    ((type length words) node)
  (ecase (policy node sb!c::stack-allocate-vector)
    (0 nil)
    ((1 2)
     ;; a vector object should fit in one page
     (values-subtypep (sb!c::lvar-derived-type words)
                      (load-time-value
                       (specifier-type `(integer 0 ,(- (/ *backend-page-size*
                                                          n-word-bytes)
                                                       vector-data-offset))))))
    (3 t)))

(define-vop (allocate-vector)
;;; ALLOCATE-VECTOR
(define-vop (allocate-vector-on-heap)
  (:args (type :scs (unsigned-reg))
         (length :scs (any-reg))
         (words :scs (any-reg)))
  (:results (result :scs (descriptor-reg) :from :load))
  (:arg-types positive-fixnum
              positive-fixnum
              positive-fixnum)
  (:policy :fast-safe)
  (: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))
    (pseudo-atomic
      (allocation result result)
      (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))))

(define-vop (allocate-vector-on-stack)
  (:args (type :scs (unsigned-reg))
         (length :scs (any-reg))
         (words :scs (any-reg) :target ecx))
  (:temporary (:sc any-reg :offset ecx-offset :from (:argument 2)) ecx)
  (:temporary (:sc any-reg :offset eax-offset :from (:argument 2)) zero)
  (:temporary (:sc any-reg :offset edi-offset :from (:argument 0)) res)
  (:results (result :scs (descriptor-reg) :from :load))
  (:arg-types positive-fixnum
              positive-fixnum
              positive-fixnum)
@@ -101,15 +113,54 @@
                              (+ (1- (ash 1 n-lowtag-bits))
                                 (* vector-data-offset n-word-bytes))))
    (inst and result (lognot lowtag-mask))
    (let ((stack-allocate-p (awhen (sb!c::node-lvar node)
                              (sb!c::lvar-dynamic-extent it))))
      (maybe-pseudo-atomic stack-allocate-p
    ;; FIXME: It would be good to check for stack overflow here.
        (allocation result result node stack-allocate-p)
    (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)))))
    (storew length result vector-length-slot other-pointer-lowtag)
    (inst xor zero zero)
    (inst rep)
    (inst stos zero)))

(in-package :sb!c)
(defoptimizer (allocate-vector stack-allocate-result)
    ((type length words) node)
  (ecase (policy node stack-allocate-vector)
    (0 nil)
    ((1 2)
     ;; a vector object should fit in one page
     (values-subtypep (lvar-derived-type words)
                      (load-time-value
                       (specifier-type `(integer 0 ,(- (/ sb!vm::*backend-page-size*
                                                          sb!vm:n-word-bytes)
                                                       sb!vm:vector-data-offset))))))
    (3 t)))

(defoptimizer (allocate-vector ltn-annotate) ((type length words) call ltn-policy)
  (let ((args (basic-combination-args call))
        (template (template-or-lose (if (awhen (node-lvar call)
                                          (lvar-dynamic-extent it))
                                        'sb!vm::allocate-vector-on-stack
                                        'sb!vm::allocate-vector-on-heap))))
    (dolist (arg args)
      (setf (lvar-info arg)
	    (make-ir2-lvar (primitive-type (lvar-type arg)))))
    (unless (is-ok-template-use template call (ltn-policy-safe-p ltn-policy))
      (ltn-default-call call)
      (return-from allocate-vector-ltn-annotate-optimizer (values)))
    (setf (basic-combination-info call) template)
    (setf (node-tail-p call) nil)

    (dolist (arg args)
      (annotate-1-value-lvar arg))))
(in-package :sb!vm)

;;;
(define-vop (allocate-code-object)
  (:args (boxed-arg :scs (any-reg) :target boxed)
	 (unboxed-arg :scs (any-reg) :target unboxed))
+8 −0
Original line number Diff line number Diff line
@@ -145,5 +145,13 @@
              ((1 1 1) (1 1 1) (1 1 1))))
         4))

;;; bug reported by Brian Downing: stack-allocated arrays were not
;;; filled with zeroes.
(defun-with-dx bdowning-2005-iv-16 ()
  (let ((a (make-array 11 :initial-element 0)))
    (declare (dynamic-extent a))
    (assert (every (lambda (x) (eql x 0)) a))))
(bdowning-2005-iv-16)


(sb-ext:quit :unix-status 104)
+1 −1
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@@ -17,4 +17,4 @@
;;; checkins which aren't released. (And occasionally for internal
;;; versions, especially for internal versions off the main CVS
;;; branch, it gets hairier, e.g. "0.pre7.14.flaky4.13".)
"0.8.21.49"
"0.8.21.50"