;;; the bits, otherwise we OR in the local conflict bits.
;;; -- If the TN is local, then we just do the block it is local to,
;;; setting always-live and OR'ing in the local conflicts.
-(defun add-location-conflicts (tn sc offset)
+(defun add-location-conflicts (tn sc offset optimize)
(declare (type tn tn) (type sc sc) (type index offset))
(let ((confs (tn-global-conflicts tn))
(sb (sc-sb sc))
(let ((num (ir2-block-number (tn-local tn))))
(setf (sbit loc-live num) 1)
(bit-ior (the local-tn-bit-vector (svref loc-confs num))
- (tn-local-conflicts tn) t))))))))
+ (tn-local-conflicts tn) t))))
+ ;; Calculating ALWAYS-LIVE-COUNT is moderately expensive, and
+ ;; currently the information isn't used unless (> SPEED
+ ;; COMPILE-SPEED).
+ (when optimize
+ (setf (svref (finite-sb-always-live-count sb) this-offset)
+ (find-location-usage sb this-offset))))))
+ (values))
+
+;; A rought measure of how much a given OFFSET in SB is currently
+;; used. Current implementation counts the amount of blocks where the
+;; offset has been marked as ALWAYS-LIVE.
+(defun find-location-usage (sb offset)
+ (declare (optimize speed))
+ (declare (type sb sb) (type index offset))
+ (let* ((always-live (svref (finite-sb-always-live sb) offset)))
+ (declare (simple-bit-vector always-live))
+ (count 1 always-live)))
;;; Return the total number of IR2-BLOCKs in COMPONENT.
(defun ir2-block-count (component)
(unless (eq (sb-kind sb) :non-packed)
(let* ((conflicts (finite-sb-conflicts sb))
(always-live (finite-sb-always-live sb))
+ (always-live-count (finite-sb-always-live-count sb))
(max-locs (length conflicts))
(last-count (finite-sb-last-block-count sb)))
(unless (zerop max-locs)
(setf (svref conflicts i) new-vec))
(setf (svref always-live i)
(make-array new-size :element-type 'bit
- :initial-element 0)))))
+ :initial-element 0))
+ (setf (svref always-live-count i) 0))))
(t
(dotimes (i (finite-sb-current-size sb))
(declare (type index i))
(dotimes (j last-count)
(declare (type index j))
(clear-bit-vector (svref conf j))))
- (clear-bit-vector (svref always-live i)))))))
+ (clear-bit-vector (svref always-live i))
+ (setf (svref always-live-count i) 0))))))
(setf (finite-sb-last-block-count sb) nblocks)
(setf (finite-sb-current-size sb) (sb-size sb))
:element-type 'bit)))
(setf (finite-sb-always-live sb) new-live))
+ (let ((new-live-count (make-array new-size)))
+ (declare (optimize speed)) ;; FILL deftransform
+ (replace new-live-count (finite-sb-always-live-count sb))
+ (fill new-live-count 0 :start size)
+ (setf (finite-sb-always-live-count sb) new-live-count))
+
(let ((new-tns (make-array new-size :initial-element nil)))
(replace new-tns (finite-sb-live-tns sb))
(fill (finite-sb-live-tns sb) nil)
(setf (tn-save-tn tn) res)
(setf (tn-save-tn res) tn)
(setf (tn-sc res) alt)
- (pack-tn res t)
+ (pack-tn res t nil)
(return res)))))
;;; Find the load function for moving from SRC to DEST and emit a
((null ref))
(incf cost))
(setf (tn-cost tn) cost))))
+
+;;; Iterate over the normal TNs, storing the depth of the deepest loop
+;;; that the TN is used in TN-LOOP-DEPTH.
+(defun assign-tn-depths (component)
+ (when *loop-analyze*
+ (do-ir2-blocks (block component)
+ (do ((vop (ir2-block-start-vop block)
+ (vop-next vop)))
+ ((null vop))
+ (flet ((find-all-tns (head-fun)
+ (collect ((tns))
+ (do ((ref (funcall head-fun vop) (tn-ref-across ref)))
+ ((null ref))
+ (tns (tn-ref-tn ref)))
+ (tns))))
+ (dolist (tn (nconc (find-all-tns #'vop-args)
+ (find-all-tns #'vop-results)
+ (find-all-tns #'vop-temps)
+ ;; What does "references in this VOP
+ ;; mean"? Probably something that isn't
+ ;; useful in this context, since these
+ ;; TN-REFs are linked with TN-REF-NEXT
+ ;; instead of TN-REF-ACROSS. --JES
+ ;; 2004-09-11
+ ;; (find-all-tns #'vop-refs)
+ ))
+ (setf (tn-loop-depth tn)
+ (max (tn-loop-depth tn)
+ (let* ((ir1-block (ir2-block-block (vop-block vop)))
+ (loop (block-loop ir1-block)))
+ (if loop
+ (loop-depth loop)
+ 0))))))))))
+
\f
;;;; load TN packing
;;;; location selection
;;; Select some location for TN in SC, returning the offset if we
-;;; succeed, and NIL if we fail. We start scanning at the Last-Offset
-;;; in an attempt to distribute the TNs across all storage.
+;;; succeed, and NIL if we fail.
;;;
-;;; We call OFFSET-CONFLICTS-IN-SB directly, rather than using
-;;; CONFLICTS-IN-SC. This allows us to more efficient in packing
-;;; multi-location TNs: we don't have to multiply the number of tests
-;;; by the TN size. This falls out naturally, since we have to be
-;;; aware of TN size anyway so that we don't call CONFLICTS-IN-SC on a
-;;; bogus offset.
+;;; For :UNBOUNDED SCs just find the smallest correctly aligned offset
+;;; where the TN doesn't conflict with the TNs that have already been
+;;; packed. For :FINITE SCs try to pack the TN into the most heavily
+;;; used locations first (as estimated in FIND-LOCATION-USAGE).
;;;
-;;; We give up on finding a location after our current pointer has
-;;; wrapped twice. This will result in testing some locations twice in
-;;; the case that we fail, but is simpler than trying to figure out
-;;; the soonest failure point.
-;;;
-;;; We also give up without bothering to wrap if the current size
-;;; isn't large enough to hold a single element of element-size
-;;; without bothering to wrap. If it doesn't fit this iteration, it
-;;; won't fit next.
-;;;
-;;; ### Note that we actually try to pack as many consecutive TNs as
-;;; possible in the same location, since we start scanning at the same
-;;; offset that the last TN was successfully packed in. This is a
-;;; weakening of the scattering hueristic that was put in to prevent
-;;; restricted VOP temps from hogging all of the registers. This way,
-;;; all of these temps probably end up in one register.
-(defun select-location (tn sc &optional use-reserved-locs)
+;;; Historically SELECT-LOCATION tried did the opposite and tried to
+;;; distribute the TNs evenly across the available locations. At least
+;;; on register-starved architectures (x86) this seems to be a bad
+;;; strategy. -- JES 2004-09-11
+(defun select-location (tn sc &key use-reserved-locs optimize)
(declare (type tn tn) (type sc sc) (inline member))
(let* ((sb (sc-sb sc))
(element-size (sc-element-size sc))
(alignment (sc-alignment sc))
(align-mask (1- alignment))
- (size (finite-sb-current-size sb))
- (start-offset (finite-sb-last-offset sb)))
- (let ((current-start
- (logandc2 (the index (+ start-offset align-mask)) align-mask))
- (wrap-p nil))
- (declare (type index current-start))
- (loop
- (when (> (+ current-start element-size) size)
- (cond ((or wrap-p (> element-size size))
- (return nil))
- (t
- (setq current-start 0)
- (setq wrap-p t))))
-
- (if (or (eq (sb-kind sb) :unbounded)
- (and (member current-start (sc-locations sc))
- (or use-reserved-locs
- (not (member current-start
- (sc-reserve-locations sc))))))
- (dotimes (i element-size
- (return-from select-location current-start))
- (declare (type index i))
- (let ((offset (+ current-start i)))
- (when (offset-conflicts-in-sb tn sb offset)
- (setq current-start
- (logandc2 (the index (+ (the index (1+ offset))
- align-mask))
- align-mask))
- (return))))
- (incf current-start alignment))))))
+ (size (finite-sb-current-size sb)))
+ (flet ((attempt-location (start-offset)
+ (dotimes (i element-size
+ (return-from select-location start-offset))
+ (declare (type index i))
+ (let ((offset (+ start-offset i)))
+ (when (offset-conflicts-in-sb tn sb offset)
+ (return (logandc2 (the index (+ (the index (1+ offset))
+ align-mask))
+ align-mask)))))))
+ (if (eq (sb-kind sb) :unbounded)
+ (loop with offset = 0
+ until (> (+ offset element-size) size) do
+ (setf offset (attempt-location offset)))
+ (let ((locations (sc-locations sc)))
+ (when optimize
+ (setf locations
+ (stable-sort (copy-list locations) #'>
+ :key (lambda (location-offset)
+ (loop for offset from location-offset
+ repeat element-size
+ maximize (svref
+ (finite-sb-always-live-count sb)
+ offset))))))
+ (dolist (offset locations)
+ (when (or use-reserved-locs
+ (not (member offset
+ (sc-reserve-locations sc))))
+ (attempt-location offset))))))))
;;; If a save TN, return the saved TN, otherwise return TN. This is
;;; useful for getting the conflicts of a TN that might be a save TN.
;;; If we are attempting to pack in the SC of the save TN for a TN
;;; with a :SPECIFIED-SAVE TN, then we pack in that location, instead
;;; of allocating a new stack location.
-(defun pack-tn (tn restricted)
+(defun pack-tn (tn restricted optimize)
(declare (type tn tn))
(let* ((original (original-tn tn))
(fsc (tn-sc tn))
(when (and save
(eq (tn-kind save) :specified-save))
(tn-sc save))))
-
(do ((sc fsc (pop alternates)))
((null sc)
(failed-to-pack-error tn restricted))
(when (eq sc specified-save-sc)
(unless (tn-offset save)
- (pack-tn save nil))
+ (pack-tn save nil optimize))
(setf (tn-offset tn) (tn-offset save))
(setf (tn-sc tn) (tn-sc save))
(return))
(let ((loc (or (find-ok-target-offset original sc)
(select-location original sc)
(and restricted
- (select-location original sc t))
+ (select-location original sc :use-reserved-locs t))
(when (eq (sb-kind (sc-sb sc)) :unbounded)
(grow-sc sc)
(or (select-location original sc)
(error "failed to pack after growing SC?"))))))
(when loc
- (add-location-conflicts original sc loc)
+ (add-location-conflicts original sc loc optimize)
(setf (tn-sc tn) sc)
(setf (tn-offset tn) loc)
(return))))))
-
(values))
;;; Pack a wired TN, checking that the offset is in bounds for the SB,
;;; locations for local call arguments (such as OLD-FP) work, since
;;; the caller and callee OLD-FP save locations may conflict when the
;;; save locations don't really (due to being in different frames.)
-(defun pack-wired-tn (tn)
+(defun pack-wired-tn (tn optimize)
(declare (type tn tn))
(let* ((sc (tn-sc tn))
(sb (sc-sb sc))
(conflicts-in-sc original sc offset))
(error "~S is wired to a location that it conflicts with." tn))
- (add-location-conflicts original sc offset)))
+ (add-location-conflicts original sc offset optimize)))
(defevent repack-block "Repacked a block due to TN unpacking.")
;; construction of this SIMPLE-BIT-VECTOR
;; until runtime.
#+sb-xc (make-array 0 :element-type 'bit)))
+ (setf (finite-sb-always-live-count sb)
+ (make-array size
+ :initial-element
+ #-sb-xc #*
+ ;; Ibid
+ #+sb-xc (make-array 0 :element-type 'fixnum)))
(fill (finite-sb-conflicts sb) nil)
(setf (finite-sb-conflicts sb)
(defun pack (component)
(unwind-protect
- (let ((optimize (policy *lexenv*
- (or (>= speed compilation-speed)
- (>= space compilation-speed))))
+ (let ((optimize nil)
(2comp (component-info component)))
(init-sb-vectors component)
+
+ ;; Determine whether we want to do more expensive packing by
+ ;; checking whether any blocks in the component have (> SPEED
+ ;; COMPILE-SPEED).
+ ;;
+ ;; FIXME: This means that a declaration can have a minor
+ ;; effect even outside its scope, and as the packing is done
+ ;; component-globally it'd be tricky to use strict scoping. I
+ ;; think this is still acceptable since it's just a tradeoff
+ ;; between compilation speed and allocation quality and
+ ;; doesn't affect the semantics of the generated code in any
+ ;; way. -- JES 2004-10-06
+ (do-ir2-blocks (block component)
+ (when (policy (block-last (ir2-block-block block))
+ (> speed compilation-speed))
+ (setf optimize t)
+ (return)))
;; Call the target functions.
(do-ir2-blocks (block component)
(when target-fun
(funcall target-fun vop)))))
-
;; Pack wired TNs first.
(do ((tn (ir2-component-wired-tns 2comp) (tn-next tn)))
((null tn))
- (pack-wired-tn tn))
+ (pack-wired-tn tn optimize))
;; Pack restricted component TNs.
(do ((tn (ir2-component-restricted-tns 2comp) (tn-next tn)))
((null tn))
(when (eq (tn-kind tn) :component)
- (pack-tn tn t)))
+ (pack-tn tn t optimize)))
;; Pack other restricted TNs.
(do ((tn (ir2-component-restricted-tns 2comp) (tn-next tn)))
((null tn))
(unless (tn-offset tn)
- (pack-tn tn t)))
-
- ;; Assign costs to normal TNs so we know which ones should always
- ;; be packed on the stack.
- (when (and optimize *pack-assign-costs*)
- (assign-tn-costs component))
-
- ;; Pack normal TNs in the order that they appear in the code. This
- ;; should have some tendency to pack important TNs first, since
- ;; control analysis favors the drop-through. This should also help
- ;; targeting, since we will pack the target TN soon after we
- ;; determine the location of the targeting TN.
- (do-ir2-blocks (block component)
- (let ((ltns (ir2-block-local-tns block)))
- (do ((i (1- (ir2-block-local-tn-count block)) (1- i)))
- ((minusp i))
- (declare (fixnum i))
- (let ((tn (svref ltns i)))
- (unless (or (null tn) (eq tn :more) (tn-offset tn))
- (pack-tn tn nil))))))
+ (pack-tn tn t optimize)))
+ ;; Assign costs to normal TNs so we know which ones should
+ ;; always be packed on the stack.
+ (when *pack-assign-costs*
+ (assign-tn-costs component)
+ (assign-tn-depths component))
+
+ ;; Allocate normal TNs, starting with the TNs that are used
+ ;; in deep loops.
+ (collect ((tns))
+ (do-ir2-blocks (block component)
+ (let ((ltns (ir2-block-local-tns block)))
+ (do ((i (1- (ir2-block-local-tn-count block)) (1- i)))
+ ((minusp i))
+ (declare (fixnum i))
+ (let ((tn (svref ltns i)))
+ (unless (or (null tn)
+ (eq tn :more)
+ (tn-offset tn))
+ ;; If loop analysis has been disabled we might as
+ ;; well revert to the old behaviour of just
+ ;; packing TNs linearly as they appear.
+ (unless *loop-analyze*
+ (pack-tn tn nil optimize))
+ (tns tn))))))
+ (dolist (tn (stable-sort (tns)
+ (lambda (a b)
+ (cond
+ ((> (tn-loop-depth a)
+ (tn-loop-depth b))
+ t)
+ ((= (tn-loop-depth a)
+ (tn-loop-depth b))
+ (> (tn-cost a) (tn-cost b)))
+ (t nil)))))
+ (unless (tn-offset tn)
+ (pack-tn tn nil optimize))))
+
;; Pack any leftover normal TNs. This is to deal with :MORE TNs,
;; which could possibly not appear in any local TN map.
(do ((tn (ir2-component-normal-tns 2comp) (tn-next tn)))
((null tn))
(unless (tn-offset tn)
- (pack-tn tn nil)))
+ (pack-tn tn nil optimize)))
;; Do load TN packing and emit saves.
(let ((*repack-blocks* nil))
(pack-load-tns block))))
(when *repack-blocks*
(loop
- (when (zerop (hash-table-count *repack-blocks*)) (return))
- (maphash (lambda (block v)
- (declare (ignore v))
- (remhash block *repack-blocks*)
- (event repack-block)
- (pack-load-tns block))
- *repack-blocks*))))
+ (when (zerop (hash-table-count *repack-blocks*)) (return))
+ (maphash (lambda (block v)
+ (declare (ignore v))
+ (remhash block *repack-blocks*)
+ (event repack-block)
+ (pack-load-tns block))
+ *repack-blocks*))))
(values))
(clean-up-pack-structures)))
projects / sbcl.git / blobdiff