(keep-going 'first-time)
;; Create a cons cell as head of the list so that removing the first
;; element does not need special-casing: `setcdr' always works.
- (lap-head (cons nil lap))
- lap0 lap1 lap2
- rest prev tmp tmp2 tmp3)
+ (lap-head (cons nil lap)))
(while keep-going
- (or (eq keep-going 'first-time)
- (byte-compile-log-lap " ---- next pass"))
- (setq prev lap-head)
+ (byte-compile-log-lap " ---- %s pass"
+ (if (eq keep-going 'first-time) "first" "next"))
(setq keep-going nil)
- (while (cdr prev)
- (setq rest (cdr prev))
- (setq lap0 (car rest)
- lap1 (nth 1 rest)
- lap2 (nth 2 rest))
-
- ;; You may notice that sequences like "dup varset discard" are
- ;; optimized but sequences like "dup varset TAG1: discard" are not.
- ;; You may be tempted to change this; resist that temptation.
-
- ;; Each clause in this `cond' statement must keep `prev' the
- ;; predecessor of the remainder of the list for inspection.
- (cond
- ;;
- ;; PUSH(K) discard(N) --> <deleted> discard(N-K), N>K
- ;; PUSH(K) discard(N) --> <deleted>, N=K
- ;; where PUSH(K) is a side-effect-free op such as const, varref, dup
- ;;
- ((and (memq (car lap1) '(byte-discard byte-discardN))
- (memq (car lap0) side-effect-free))
- (setq keep-going t)
- (let* ((pushes (aref byte-stack+-info (symbol-value (car lap0))))
- (pops (if (eq (car lap1) 'byte-discardN) (cdr lap1) 1))
- (net-pops (- pops pushes)))
- (cond ((= net-pops 0)
- (byte-compile-log-lap " %s %s\t-->\t<deleted>" lap0 lap1)
- (setcdr prev (cddr rest)))
- ((> net-pops 0)
- (byte-compile-log-lap
- " %s %s\t-->\t<deleted> discard(%d)" lap0 lap1 net-pops)
- (setcar rest (if (eql net-pops 1)
+ (let ((prev lap-head))
+ (while (cdr prev)
+ (let* ((rest (cdr prev))
+ (lap0 (car rest))
+ (lap1 (nth 1 rest))
+ (lap2 (nth 2 rest)))
+
+ ;; You may notice that sequences like "dup varset discard" are
+ ;; optimized but sequences like "dup varset TAG1: discard" are not.
+ ;; You may be tempted to change this; resist that temptation.
+
+ ;; Each clause in this `cond' statement must keep `prev' the
+ ;; predecessor of the remainder of the list for inspection.
+ (cond
+ ;;
+ ;; PUSH(K) discard(N) --> <deleted> discard(N-K), N>K
+ ;; PUSH(K) discard(N) --> <deleted>, N=K
+ ;; where PUSH(K) is a side-effect-free op such as
+ ;; const, varref, dup
+ ;;
+ ((and (memq (car lap1) '(byte-discard byte-discardN))
+ (memq (car lap0) side-effect-free))
+ (setq keep-going t)
+ (let* ((pushes (aref byte-stack+-info (symbol-value (car lap0))))
+ (pops (if (eq (car lap1) 'byte-discardN) (cdr lap1) 1))
+ (net-pops (- pops pushes)))
+ (cond ((= net-pops 0)
+ (byte-compile-log-lap " %s %s\t-->\t<deleted>"
+ lap0 lap1)
+ (setcdr prev (cddr rest)))
+ ((> net-pops 0)
+ (byte-compile-log-lap
+ " %s %s\t-->\t<deleted> discard(%d)"
+ lap0 lap1 net-pops)
+ (setcar rest (if (eql net-pops 1)
+ (cons 'byte-discard nil)
+ (cons 'byte-discardN net-pops)))
+ (setcdr rest (cddr rest)))
+ (t (error "Optimizer error: too much on the stack")))))
+ ;;
+ ;; goto(X) X: --> X:
+ ;; goto-if-[not-]nil(X) X: --> discard X:
+ ;;
+ ((and (memq (car lap0) byte-goto-ops)
+ (eq (cdr lap0) lap1))
+ (cond ((eq (car lap0) 'byte-goto)
+ (byte-compile-log-lap " %s %s\t-->\t<deleted> %s"
+ lap0 lap1 lap1)
+ (setcdr prev (cdr rest)))
+ ((memq (car lap0) byte-goto-always-pop-ops)
+ (byte-compile-log-lap " %s %s\t-->\tdiscard %s"
+ lap0 lap1 lap1)
+ (setcar lap0 'byte-discard)
+ (setcdr lap0 0))
+ ;; goto-*-else-pop(X) cannot occur here because it would
+ ;; be a depth conflict.
+ (t (error "Depth conflict at tag %d" (nth 2 lap0))))
+ (setq keep-going t))
+ ;;
+ ;; varset-X varref-X --> dup varset-X
+ ;; varbind-X varref-X --> dup varbind-X
+ ;; const/dup varset-X varref-X --> const/dup varset-X const/dup
+ ;; const/dup varbind-X varref-X --> const/dup varbind-X const/dup
+ ;; The latter two can enable other optimizations.
+ ;;
+ ;; For lexical variables, we could do the same
+ ;; stack-set-X+1 stack-ref-X --> dup stack-set-X+2
+ ;; but this is a very minor gain, since dup is stack-ref-0,
+ ;; i.e. it's only better if X>5, and even then it comes
+ ;; at the cost of an extra stack slot. Let's not bother.
+ ((and (eq 'byte-varref (car lap2))
+ (eq (cdr lap1) (cdr lap2))
+ (memq (car lap1) '(byte-varset byte-varbind))
+ (let ((tmp (memq (car (cdr lap2)) byte-boolean-vars)))
+ (and
+ (not (and tmp (not (eq (car lap0) 'byte-constant))))
+ (progn
+ (setq keep-going t)
+ (if (memq (car lap0) '(byte-constant byte-dup))
+ (let ((tmp (if (or (not tmp)
+ (macroexp--const-symbol-p
+ (car (cdr lap0))))
+ (cdr lap0)
+ (byte-compile-get-constant t))))
+ (byte-compile-log-lap " %s %s %s\t-->\t%s %s %s"
+ lap0 lap1 lap2 lap0 lap1
+ (cons (car lap0) tmp))
+ (setcar lap2 (car lap0))
+ (setcdr lap2 tmp))
+ (byte-compile-log-lap " %s %s\t-->\tdup %s"
+ lap1 lap2 lap1)
+ (setcar lap2 (car lap1))
+ (setcar lap1 'byte-dup)
+ (setcdr lap1 0)
+ ;; The stack depth gets locally increased, so we will
+ ;; increase maxdepth in case depth = maxdepth here.
+ ;; This can cause the third argument to byte-code to
+ ;; be larger than necessary.
+ (setq add-depth 1))
+ t)))))
+ ;;
+ ;; dup varset-X discard --> varset-X
+ ;; dup varbind-X discard --> varbind-X
+ ;; dup stack-set-X discard --> stack-set-X-1
+ ;; (the varbind variant can emerge from other optimizations)
+ ;;
+ ((and (eq 'byte-dup (car lap0))
+ (eq 'byte-discard (car lap2))
+ (memq (car lap1) '(byte-varset byte-varbind
+ byte-stack-set)))
+ (setq keep-going t)
+ (setcdr prev (cdr rest)) ; remove dup
+ (setcdr (cdr rest) (cdddr rest)) ; remove discard
+ (setq prev (cdr rest)) ; FIXME: temporary compat hack
+ (cond ((not (eq (car lap1) 'byte-stack-set))
+ (byte-compile-log-lap " %s %s %s\t-->\t%s"
+ lap0 lap1 lap2 lap1))
+ ((eql (cdr lap1) 1)
+ (byte-compile-log-lap " %s %s %s\t-->\t<deleted>"
+ lap0 lap1 lap2))
+ (t
+ (let ((n (1- (cdr lap1))))
+ (byte-compile-log-lap " %s %s %s\t-->\t%s"
+ lap0 lap1 lap2
+ (cons (car lap1) n))
+ (setcdr lap1 n)))))
+ ;;
+ ;; not goto-X-if-nil --> goto-X-if-non-nil
+ ;; not goto-X-if-non-nil --> goto-X-if-nil
+ ;;
+ ;; it is wrong to do the same thing for the -else-pop variants.
+ ;;
+ ((and (eq 'byte-not (car lap0))
+ (memq (car lap1) '(byte-goto-if-nil byte-goto-if-not-nil)))
+ (let ((not-goto (if (eq (car lap1) 'byte-goto-if-nil)
+ 'byte-goto-if-not-nil
+ 'byte-goto-if-nil)))
+ (byte-compile-log-lap " not %s\t-->\t%s"
+ lap1 (cons not-goto (cdr lap1)))
+ (setcar lap1 not-goto)
+ (setcdr prev (cdr rest)) ; delete not
+ (setq keep-going t)))
+ ;;
+ ;; goto-X-if-nil goto-Y X: --> goto-Y-if-non-nil X:
+ ;; goto-X-if-non-nil goto-Y X: --> goto-Y-if-nil X:
+ ;;
+ ;; it is wrong to do the same thing for the -else-pop variants.
+ ;;
+ ((and (memq (car lap0)
+ '(byte-goto-if-nil byte-goto-if-not-nil)) ; gotoX
+ (eq 'byte-goto (car lap1)) ; gotoY
+ (eq (cdr lap0) lap2)) ; TAG X
+ (let ((inverse (if (eq 'byte-goto-if-nil (car lap0))
+ 'byte-goto-if-not-nil 'byte-goto-if-nil)))
+ (byte-compile-log-lap " %s %s %s\t-->\t%s %s"
+ lap0 lap1 lap2
+ (cons inverse (cdr lap1)) lap2)
+ (setcdr prev (cdr rest))
+ (setcar lap1 inverse)
+ (setq keep-going t)))
+ ;;
+ ;; const goto-if-* --> whatever
+ ;;
+ ((and (eq 'byte-constant (car lap0))
+ (memq (car lap1) byte-conditional-ops)
+ ;; Must be an actual constant, not a closure variable.
+ (consp (cdr lap0)))
+ (cond ((if (memq (car lap1) '(byte-goto-if-nil
+ byte-goto-if-nil-else-pop))
+ (car (cdr lap0))
+ (not (car (cdr lap0))))
+ ;; Branch not taken.
+ (byte-compile-log-lap " %s %s\t-->\t<deleted>"
+ lap0 lap1)
+ (setcdr prev (cddr rest))) ; delete both
+ ((memq (car lap1) byte-goto-always-pop-ops)
+ ;; Always-pop branch taken.
+ (byte-compile-log-lap " %s %s\t-->\t%s"
+ lap0 lap1
+ (cons 'byte-goto (cdr lap1)))
+ (setcdr prev (cdr rest)) ; delete const
+ (setcar lap1 'byte-goto))
+ (t ; -else-pop branch taken: keep const
+ (byte-compile-log-lap " %s %s\t-->\t%s %s"
+ lap0 lap1
+ lap0 (cons 'byte-goto (cdr lap1)))
+ (setcar lap1 'byte-goto)
+ (setq prev (cdr prev)) ; FIXME: temporary compat hack
+ ))
+ (setq keep-going t))
+ ;;
+ ;; varref-X varref-X --> varref-X dup
+ ;; varref-X [dup ...] varref-X --> varref-X [dup ...] dup
+ ;; stackref-X [dup ...] stackref-X+N --> stackref-X [dup ...] dup
+ ;; We don't optimize the const-X variations on this here,
+ ;; because that would inhibit some goto optimizations; we
+ ;; optimize the const-X case after all other optimizations.
+ ;;
+ ((and (memq (car lap0) '(byte-varref byte-stack-ref))
+ (let ((tmp (cdr rest))
+ (tmp2 0))
+ (while (eq (car (car tmp)) 'byte-dup)
+ (setq tmp2 (1+ tmp2))
+ (setq tmp (cdr tmp)))
+ (and (eq (if (eq 'byte-stack-ref (car lap0))
+ (+ tmp2 1 (cdr lap0))
+ (cdr lap0))
+ (cdr (car tmp)))
+ (eq (car lap0) (car (car tmp)))
+ (progn
+ (when (memq byte-optimize-log '(t byte))
+ (let ((str "")
+ (tmp2 (cdr rest)))
+ (while (not (eq tmp tmp2))
+ (setq tmp2 (cdr tmp2))
+ (setq str (concat str " dup")))
+ (byte-compile-log-lap " %s%s %s\t-->\t%s%s dup"
+ lap0 str lap0 lap0 str)))
+ (setq keep-going t)
+ (setcar (car tmp) 'byte-dup)
+ (setcdr (car tmp) 0)
+ t)))))
+ ;;
+ ;; TAG1: TAG2: --> <deleted> TAG2:
+ ;; (and other references to TAG1 are replaced with TAG2)
+ ;;
+ ((and (eq (car lap0) 'TAG)
+ (eq (car lap1) 'TAG))
+ (byte-compile-log-lap " adjacent tags %d and %d merged"
+ (nth 1 lap1) (nth 1 lap0))
+ (let ((tmp3 (cdr lap-head)))
+ (while (let ((tmp2 (rassq lap0 tmp3)))
+ (and tmp2
+ (progn
+ (setcdr tmp2 lap1)
+ (setq tmp3 (cdr (memq tmp2 tmp3)))
+ t))))
+ (setcdr prev (cdr rest))
+ (setq keep-going t)
+ ;; replace references to tag in jump tables, if any
+ (dolist (table byte-compile-jump-tables)
+ (maphash #'(lambda (value tag)
+ (when (equal tag lap0)
+ (puthash value lap1 table)))
+ table))))
+ ;;
+ ;; unused-TAG: --> <deleted>
+ ;;
+ ((and (eq 'TAG (car lap0))
+ (not (rassq lap0 (cdr lap-head)))
+ ;; make sure this tag isn't used in a jump-table
+ (cl-loop for table in byte-compile-jump-tables
+ when (member lap0 (hash-table-values table))
+ return nil finally return t))
+ (byte-compile-log-lap " unused tag %d removed" (nth 1 lap0))
+ (setcdr prev (cdr rest))
+ (setq keep-going t))
+ ;;
+ ;; goto ... --> goto <delete until TAG or end>
+ ;; return ... --> return <delete until TAG or end>
+ ;;
+ ((and (memq (car lap0) '(byte-goto byte-return))
+ (not (memq (car lap1) '(TAG nil))))
+ (let ((i 0)
+ (tmp rest)
+ (opt-p (memq byte-optimize-log '(t byte)))
+ str deleted)
+ (while (and (setq tmp (cdr tmp))
+ (not (eq 'TAG (car (car tmp)))))
+ (if opt-p (setq deleted (cons (car tmp) deleted)
+ str (concat str " %s")
+ i (1+ i))))
+ (if opt-p
+ (let ((tagstr
+ (if (eq 'TAG (car (car tmp)))
+ (format "%d:" (car (cdr (car tmp))))
+ (or (car tmp) ""))))
+ (if (< i 6)
+ (apply 'byte-compile-log-lap-1
+ (concat " %s" str
+ " %s\t-->\t%s <deleted> %s")
+ lap0
+ (nconc (nreverse deleted)
+ (list tagstr lap0 tagstr)))
+ (byte-compile-log-lap
+ " %s <%d unreachable op%s> %s\t-->\t%s <deleted> %s"
+ lap0 i (if (= i 1) "" "s")
+ tagstr lap0 tagstr))))
+ (setcdr rest tmp)
+ (setq prev rest) ; FIXME: temporary compat hack
+ (setq keep-going t)))
+ ;;
+ ;; <safe-op> unbind --> unbind <safe-op>
+ ;; (this may enable other optimizations.)
+ ;;
+ ((and (eq 'byte-unbind (car lap1))
+ (memq (car lap0) byte-after-unbind-ops))
+ (byte-compile-log-lap " %s %s\t-->\t%s %s" lap0 lap1 lap1 lap0)
+ (setcar rest lap1)
+ (setcar (cdr rest) lap0)
+ (setq keep-going t))
+ ;;
+ ;; varbind-X unbind-N --> discard unbind-(N-1)
+ ;; save-excursion unbind-N --> unbind-(N-1)
+ ;; save-restriction unbind-N --> unbind-(N-1)
+ ;; save-current-buffer unbind-N --> unbind-(N-1)
+ ;;
+ ((and (eq 'byte-unbind (car lap1))
+ (memq (car lap0) '(byte-varbind byte-save-excursion
+ byte-save-restriction
+ byte-save-current-buffer))
+ (< 0 (cdr lap1)))
+ (setcdr lap1 (1- (cdr lap1)))
+ (when (zerop (cdr lap1))
+ (setcdr rest (cddr rest)))
+ (if (eq (car lap0) 'byte-varbind)
+ (setcar rest (cons 'byte-discard 0))
+ (setcdr prev (cddr prev)))
+ (byte-compile-log-lap " %s %s\t-->\t%s %s"
+ lap0 (cons (car lap1) (1+ (cdr lap1)))
+ (if (eq (car lap0) 'byte-varbind)
+ (car rest)
+ (car (cdr rest)))
+ (if (and (/= 0 (cdr lap1))
+ (eq (car lap0) 'byte-varbind))
+ (car (cdr rest))
+ ""))
+ (setq keep-going t))
+ ;;
+ ;; goto*-X ... X: goto-Y --> goto*-Y
+ ;; goto-X ... X: return --> return
+ ;;
+ ((and (memq (car lap0) byte-goto-ops)
+ (let ((tmp (nth 1 (memq (cdr lap0) (cdr lap-head)))))
+ (and
+ (memq (car tmp) '(byte-goto byte-return))
+ (or (eq (car lap0) 'byte-goto)
+ (eq (car tmp) 'byte-goto))
+ (not (eq (cdr tmp) (cdr lap0)))
+ (progn
+ ;; FIXME: inaccurate log message when lap0 = goto-if-*
+ (byte-compile-log-lap " %s [%s]\t-->\t%s"
+ (car lap0) tmp tmp)
+ (when (eq (car tmp) 'byte-return)
+ (setcar lap0 'byte-return))
+ (setcdr lap0 (cdr tmp))
+ (setq prev (cdr prev)) ; FIXME: temporary compat hack
+ (setq keep-going t)
+ t)))))
+
+ ;;
+ ;; OP goto(X) Y: OP X: -> Y: OP X:
+ ;;
+ ((and (eq (car lap1) 'byte-goto)
+ (eq (car lap2) 'TAG)
+ (let ((lap3 (nth 3 rest)))
+ (and (eq (car lap0) (car lap3))
+ (eq (cdr lap0) (cdr lap3))
+ (eq (cdr lap1) (nth 4 rest)))))
+ (byte-compile-log-lap " %s %s %s %s %s\t-->\t%s %s %s"
+ lap0 lap1 lap2
+ (nth 3 rest) (nth 4 rest)
+ lap2 (nth 3 rest) (nth 4 rest))
+ (setcdr prev (cddr rest))
+ (setq keep-going t))
+
+ ;;
+ ;; OP const return --> const return
+ ;; where OP is side-effect-free (or mere stack manipulation).
+ ;;
+ ((and (eq (car lap1) 'byte-constant)
+ (eq (car (nth 2 rest)) 'byte-return)
+ (or (memq (car lap0) '( byte-discard byte-discardN
+ byte-discardN-preserve-tos
+ byte-stack-set))
+ (memq (car lap0) side-effect-free)))
+ (setq keep-going t)
+ (setq add-depth 1)
+ (setcdr prev (cdr rest))
+ (byte-compile-log-lap " %s %s %s\t-->\t%s %s"
+ lap0 lap1 (nth 2 rest) lap1 (nth 2 rest)))
+
+ ;;
+ ;; goto-*-else-pop X ... X: goto-if-* --> whatever
+ ;; goto-*-else-pop X ... X: discard --> whatever
+ ;;
+ ((and (memq (car lap0) '(byte-goto-if-nil-else-pop
+ byte-goto-if-not-nil-else-pop))
+ (let ((tmp (cdr (memq (cdr lap0) (cdr lap-head)))))
+ (and
+ (memq (caar tmp)
+ (eval-when-compile
+ (cons 'byte-discard byte-conditional-ops)))
+ (not (eq lap0 (car tmp)))
+ (let ((tmp2 (car tmp))
+ (tmp3 (assq (car lap0)
+ '((byte-goto-if-nil-else-pop
+ byte-goto-if-nil)
+ (byte-goto-if-not-nil-else-pop
+ byte-goto-if-not-nil)))))
+ (if (memq (car tmp2) tmp3)
+ (progn (setcar lap0 (car tmp2))
+ (setcdr lap0 (cdr tmp2))
+ (byte-compile-log-lap
+ " %s-else-pop [%s]\t-->\t%s"
+ (car lap0) tmp2 lap0))
+ ;; Get rid of the -else-pop's and jump one
+ ;; step further.
+ (or (eq 'TAG (car (nth 1 tmp)))
+ (setcdr tmp (cons (byte-compile-make-tag)
+ (cdr tmp))))
+ (byte-compile-log-lap " %s [%s]\t-->\t%s <skip>"
+ (car lap0) tmp2 (nth 1 tmp3))
+ (setcar lap0 (nth 1 tmp3))
+ (setcdr lap0 (nth 1 tmp)))
+ (setq prev (cdr prev)) ; FIXME: temporary compat hack
+ (setq keep-going t)
+ t)))))
+ ;;
+ ;; const goto-X ... X: goto-if-* --> whatever
+ ;; const goto-X ... X: discard --> whatever
+ ;;
+ ((and (eq (car lap0) 'byte-constant)
+ (eq (car lap1) 'byte-goto)
+ (let ((tmp (cdr (memq (cdr lap1) (cdr lap-head)))))
+ (and
+ (memq (caar tmp)
+ (eval-when-compile
+ (cons 'byte-discard byte-conditional-ops)))
+ (not (eq lap1 (car tmp)))
+ (let ((tmp2 (car tmp)))
+ (cond ((and (consp (cdr lap0))
+ (memq (car tmp2)
+ (if (null (car (cdr lap0)))
+ '(byte-goto-if-nil
+ byte-goto-if-nil-else-pop)
+ '(byte-goto-if-not-nil
+ byte-goto-if-not-nil-else-pop))))
+ (byte-compile-log-lap
+ " %s goto [%s]\t-->\t%s %s"
+ lap0 tmp2 lap0 tmp2)
+ (setcar lap1 (car tmp2))
+ (setcdr lap1 (cdr tmp2))
+ ;; Let next step fix the (const,goto-if*) seq.
+ (setq keep-going t))
+ ((or (consp (cdr lap0))
+ (eq (car tmp2) 'byte-discard))
+ ;; Jump one step further
+ (byte-compile-log-lap
+ " %s goto [%s]\t-->\t<deleted> goto <skip>"
+ lap0 tmp2)
+ (or (eq 'TAG (car (nth 1 tmp)))
+ (setcdr tmp (cons (byte-compile-make-tag)
+ (cdr tmp))))
+ (setcdr lap1 (car (cdr tmp)))
+ (setcdr prev (cdr rest))
+ (setq keep-going t))
+ (t
+ (setq prev (cdr prev))))
+ t)))))
+ ;;
+ ;; X: varref-Y ... varset-Y goto-X -->
+ ;; X: varref-Y Z: ... dup varset-Y goto-Z
+ ;; (varset-X goto-BACK, BACK: varref-X --> copy the varref down.)
+ ;; (This is so usual for while loops that it is worth handling).
+ ;;
+ ;; Here again, we could do it for stack-ref/stack-set, but
+ ;; that's replacing a stack-ref-Y with a stack-ref-0, which
+ ;; is a very minor improvement (if any), at the cost of
+ ;; more stack use and more byte-code. Let's not do it.
+ ;;
+ ((and (eq (car lap1) 'byte-varset)
+ (eq (car lap2) 'byte-goto)
+ (not (memq (cdr lap2) rest)) ;Backwards jump
+ (let ((tmp (cdr (memq (cdr lap2) (cdr lap-head)))))
+ (and
+ (eq (car (car tmp)) 'byte-varref)
+ (eq (cdr (car tmp)) (cdr lap1))
+ (not (memq (car (cdr lap1)) byte-boolean-vars))
+ (let ((newtag (byte-compile-make-tag)))
+ (byte-compile-log-lap
+ " %s: %s ... %s %s\t-->\t%s: %s %s: ... %s %s %s"
+ (nth 1 (cdr lap2)) (car tmp)
+ lap1 lap2
+ (nth 1 (cdr lap2)) (car tmp)
+ (nth 1 newtag) 'byte-dup lap1
+ (cons 'byte-goto newtag)
+ )
+ (setcdr rest (cons (cons 'byte-dup 0) (cdr rest)))
+ (setcdr tmp (cons (setcdr lap2 newtag) (cdr tmp)))
+ (setq add-depth 1)
+ (setq keep-going t)
+ t)))))
+ ;;
+ ;; goto-X Y: ... X: goto-if*-Y --> goto-if-not-*-X+1 Y:
+ ;; (This can pull the loop test to the end of the loop)
+ ;;
+ ((and (eq (car lap0) 'byte-goto)
+ (eq (car lap1) 'TAG)
+ (let ((tmp (cdr (memq (cdr lap0) (cdr lap-head)))))
+ (and
+ (eq lap1 (cdar tmp))
+ (memq (car (car tmp))
+ '( byte-goto byte-goto-if-nil byte-goto-if-not-nil
+ byte-goto-if-nil-else-pop))
+ (let ((newtag (byte-compile-make-tag)))
+ (byte-compile-log-lap
+ " %s %s ... %s %s\t-->\t%s ... %s"
+ lap0 lap1 (cdr lap0) (car tmp)
+ (cons (cdr (assq (car (car tmp))
+ '((byte-goto-if-nil
+ . byte-goto-if-not-nil)
+ (byte-goto-if-not-nil
+ . byte-goto-if-nil)
+ (byte-goto-if-nil-else-pop
+ . byte-goto-if-not-nil-else-pop)
+ (byte-goto-if-not-nil-else-pop
+ . byte-goto-if-nil-else-pop))))
+ newtag)
+ newtag)
+ (setcdr tmp (cons (setcdr lap0 newtag) (cdr tmp)))
+ (when (eq (car (car tmp)) 'byte-goto-if-nil-else-pop)
+ ;; We can handle this case but not the
+ ;; -if-not-nil case, because we won't know
+ ;; which non-nil constant to push.
+ (setcdr rest
+ (cons (cons 'byte-constant
+ (byte-compile-get-constant nil))
+ (cdr rest))))
+ (setcar lap0 (nth 1 (memq (car (car tmp))
+ '(byte-goto-if-nil-else-pop
+ byte-goto-if-not-nil
+ byte-goto-if-nil
+ byte-goto-if-not-nil
+ byte-goto byte-goto))))
+ (setq keep-going t)
+ t)))))
+
+ ;;
+ ;; discardN-preserve-tos(X) discardN-preserve-tos(Y)
+ ;; --> discardN-preserve-tos(X+Y)
+ ;; where stack-set(1) is accepted as discardN-preserve-tos(1)
+ ;;
+ ((and (or (eq (car lap0) 'byte-discardN-preserve-tos)
+ (and (eq (car lap0) 'byte-stack-set)
+ (eql (cdr lap0) 1)))
+ (or (eq (car lap1) 'byte-discardN-preserve-tos)
+ (and (eq (car lap1) 'byte-stack-set)
+ (eql (cdr lap1) 1))))
+ (setq keep-going t)
+ (let ((new-op (cons 'byte-discardN-preserve-tos
+ ;; This happens to work even when either
+ ;; op is stack-set(1).
+ (+ (cdr lap0) (cdr lap1)))))
+ (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 new-op)
+ (setcar rest new-op)
+ (setcdr rest (cddr rest))
+ (setq prev rest) ; FIXME: temporary compat hack
+ ))
+
+ ;;
+ ;; stack-set-M [discard/discardN ...] --> discardN-preserve-tos
+ ;; stack-set-M [discard/discardN ...] --> discardN
+ ;;
+ ((and (eq (car lap0) 'byte-stack-set)
+ (memq (car lap1) '(byte-discard byte-discardN))
+ (let ((tmp2 (1- (cdr lap0)))
+ (tmp3 0)
+ (tmp (cdr rest)))
+ ;; See if enough discard operations follow to expose or
+ ;; destroy the value stored by the stack-set.
+ (while (memq (car (car tmp)) '(byte-discard byte-discardN))
+ (setq tmp3
+ (+ tmp3 (if (eq (car (car tmp)) 'byte-discard)
+ 1
+ (cdr (car tmp)))))
+ (setq tmp (cdr tmp)))
+ (and
+ (>= tmp3 tmp2)
+ (progn
+ ;; Do the optimization.
+ (setcdr prev (cdr rest))
+ (setcar lap1
+ (if (= tmp2 tmp3)
+ ;; The value stored is the new TOS, so pop
+ ;; one more value (to get rid of the old
+ ;; value) using TOS-preserving discard.
+ 'byte-discardN-preserve-tos
+ ;; Otherwise, the value stored is lost,
+ ;; so just use a normal discard.
+ 'byte-discardN))
+ (setcdr lap1 (1+ tmp3))
+ (setcdr (cdr rest) tmp)
+ (byte-compile-log-lap
+ " %s [discard/discardN]...\t-->\t%s" lap0 lap1)
+ ;; FIXME: shouldn't we do (setq keep-going t) here?
+ t
+ )))))
+
+ ;;
+ ;; discardN-preserve-tos return --> return
+ ;; dup return --> return
+ ;; stack-set(1) return --> return
+ ;;
+ ((and (eq (car lap1) 'byte-return)
+ (or (memq (car lap0) '(byte-discardN-preserve-tos byte-dup))
+ (and (eq (car lap0) 'byte-stack-set)
+ (= (cdr lap0) 1))))
+ (setq keep-going t)
+ ;; The byte-code interpreter will pop the stack for us, so
+ ;; we can just leave stuff on it.
+ (setcdr prev (cdr rest))
+ (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 lap1))
+
+ ;;
+ ;; goto-X ... X: discard ==> discard goto-Y ... X: discard Y:
+ ;;
+ ((and (eq (car lap0) 'byte-goto)
+ (let ((tmp (cdr (memq (cdr lap0) (cdr lap-head)))))
+ (and
+ tmp
+ (or (memq (caar tmp) '(byte-discard byte-discardN))
+ ;; Make sure we don't hoist a discardN-preserve-tos
+ ;; that really should be merged or deleted instead.
+ (and (eq (caar tmp) 'byte-discardN-preserve-tos)
+ (let ((next (cadr tmp)))
+ (not (or (memq (car next)
+ '(byte-discardN-preserve-tos
+ byte-return))
+ (and (eq (car next) 'byte-stack-set)
+ (eql (cdr next) 1)))))))
+ (progn
+ (byte-compile-log-lap
+ " goto-X .. X: \t-->\t%s goto-X.. X: %s Y:"
+ (car tmp) (car tmp))
+ (setq keep-going t)
+ (let* ((newtag (byte-compile-make-tag))
+ ;; Make a copy, since we sometimes modify
+ ;; insts in-place!
+ (newdiscard (cons (caar tmp) (cdar tmp)))
+ (newjmp (cons (car lap0) newtag)))
+ ;; Push new tag after the discard.
+ (push newtag (cdr tmp))
+ (setcar rest newdiscard)
+ (push newjmp (cdr rest)))
+ t)))))
+
+ ;;
+ ;; const discardN-preserve-tos ==> discardN const
+ ;; const stack-set(1) ==> discard const
+ ;;
+ ((and (eq (car lap0) 'byte-constant)
+ (or (eq (car lap1) 'byte-discardN-preserve-tos)
+ (and (eq (car lap1) 'byte-stack-set)
+ (eql (cdr lap1) 1))))
+ (setq keep-going t)
+ (let ((newdiscard (if (eql (cdr lap1) 1)
(cons 'byte-discard nil)
- (cons 'byte-discardN net-pops)))
- (setcdr rest (cddr rest)))
- (t (error "Optimizer error: too much on the stack")))))
- ;;
- ;; goto(X) X: --> X:
- ;; goto-if-[not-]nil(X) X: --> discard X:
- ;;
- ((and (memq (car lap0) byte-goto-ops)
- (eq (cdr lap0) lap1))
- (cond ((eq (car lap0) 'byte-goto)
- (byte-compile-log-lap " %s %s\t-->\t<deleted> %s"
- lap0 lap1 lap1)
- (setcdr prev (cdr rest)))
- ((memq (car lap0) byte-goto-always-pop-ops)
- (byte-compile-log-lap " %s %s\t-->\tdiscard %s"
- lap0 lap1 lap1)
- (setcar lap0 'byte-discard)
- (setcdr lap0 0))
- ;; goto-*-else-pop(X) cannot occur here because it would
- ;; be a depth conflict.
- (t (error "Depth conflict at tag %d" (nth 2 lap0))))
- (setq keep-going t))
- ;;
- ;; varset-X varref-X --> dup varset-X
- ;; varbind-X varref-X --> dup varbind-X
- ;; const/dup varset-X varref-X --> const/dup varset-X const/dup
- ;; const/dup varbind-X varref-X --> const/dup varbind-X const/dup
- ;; The latter two can enable other optimizations.
- ;;
- ;; For lexical variables, we could do the same
- ;; stack-set-X+1 stack-ref-X --> dup stack-set-X+2
- ;; but this is a very minor gain, since dup is stack-ref-0,
- ;; i.e. it's only better if X>5, and even then it comes
- ;; at the cost of an extra stack slot. Let's not bother.
- ((and (eq 'byte-varref (car lap2))
- (eq (cdr lap1) (cdr lap2))
- (memq (car lap1) '(byte-varset byte-varbind))
- (not (and (setq tmp (memq (car (cdr lap2)) byte-boolean-vars))
- (not (eq (car lap0) 'byte-constant)))))
- (setq keep-going t)
- (if (memq (car lap0) '(byte-constant byte-dup))
- (progn
- (setq tmp (if (or (not tmp)
- (macroexp--const-symbol-p
- (car (cdr lap0))))
- (cdr lap0)
- (byte-compile-get-constant t)))
- (byte-compile-log-lap " %s %s %s\t-->\t%s %s %s"
- lap0 lap1 lap2 lap0 lap1
- (cons (car lap0) tmp))
- (setcar lap2 (car lap0))
- (setcdr lap2 tmp))
- (byte-compile-log-lap " %s %s\t-->\tdup %s" lap1 lap2 lap1)
- (setcar lap2 (car lap1))
- (setcar lap1 'byte-dup)
- (setcdr lap1 0)
- ;; The stack depth gets locally increased, so we will
- ;; increase maxdepth in case depth = maxdepth here.
- ;; This can cause the third argument to byte-code to
- ;; be larger than necessary.
- (setq add-depth 1)))
- ;;
- ;; dup varset-X discard --> varset-X
- ;; dup varbind-X discard --> varbind-X
- ;; dup stack-set-X discard --> stack-set-X-1
- ;; (the varbind variant can emerge from other optimizations)
- ;;
- ((and (eq 'byte-dup (car lap0))
- (eq 'byte-discard (car lap2))
- (memq (car lap1) '(byte-varset byte-varbind
- byte-stack-set)))
- (setq keep-going t)
- (setcdr prev (cdr rest)) ; remove dup
- (setcdr (cdr rest) (cdddr rest)) ; remove discard
- (setq prev (cdr rest)) ; FIXME: temporary compat hack
- (cond ((not (eq (car lap1) 'byte-stack-set))
- (byte-compile-log-lap " %s %s %s\t-->\t%s"
- lap0 lap1 lap2 lap1))
- ((eql (cdr lap1) 1)
- (byte-compile-log-lap " %s %s %s\t-->\t<deleted>"
- lap0 lap1 lap2))
- (t
- (let ((n (1- (cdr lap1))))
- (byte-compile-log-lap " %s %s %s\t-->\t%s"
- lap0 lap1 lap2
- (cons (car lap1) n))
- (setcdr lap1 n)))))
- ;;
- ;; not goto-X-if-nil --> goto-X-if-non-nil
- ;; not goto-X-if-non-nil --> goto-X-if-nil
- ;;
- ;; it is wrong to do the same thing for the -else-pop variants.
- ;;
- ((and (eq 'byte-not (car lap0))
- (memq (car lap1) '(byte-goto-if-nil byte-goto-if-not-nil)))
- (let ((not-goto (if (eq (car lap1) 'byte-goto-if-nil)
- 'byte-goto-if-not-nil
- 'byte-goto-if-nil)))
- (byte-compile-log-lap " not %s\t-->\t%s"
- lap1 (cons not-goto (cdr lap1)))
- (setcar lap1 not-goto)
- (setcdr prev (cdr rest)) ; delete not
- (setq keep-going t)))
- ;;
- ;; goto-X-if-nil goto-Y X: --> goto-Y-if-non-nil X:
- ;; goto-X-if-non-nil goto-Y X: --> goto-Y-if-nil X:
- ;;
- ;; it is wrong to do the same thing for the -else-pop variants.
- ;;
- ((and (memq (car lap0)
- '(byte-goto-if-nil byte-goto-if-not-nil)) ; gotoX
- (eq 'byte-goto (car lap1)) ; gotoY
- (eq (cdr lap0) lap2)) ; TAG X
- (let ((inverse (if (eq 'byte-goto-if-nil (car lap0))
- 'byte-goto-if-not-nil 'byte-goto-if-nil)))
- (byte-compile-log-lap " %s %s %s\t-->\t%s %s"
- lap0 lap1 lap2
- (cons inverse (cdr lap1)) lap2)
- (setcdr prev (cdr rest))
- (setcar lap1 inverse)
- (setq keep-going t)))
- ;;
- ;; const goto-if-* --> whatever
- ;;
- ((and (eq 'byte-constant (car lap0))
- (memq (car lap1) byte-conditional-ops)
- ;; Must be an actual constant, not a closure variable.
- (consp (cdr lap0)))
- (cond ((if (memq (car lap1) '(byte-goto-if-nil
- byte-goto-if-nil-else-pop))
- (car (cdr lap0))
- (not (car (cdr lap0))))
- ;; Branch not taken.
- (byte-compile-log-lap " %s %s\t-->\t<deleted>"
- lap0 lap1)
- (setcdr prev (cddr rest))) ; delete both
- ((memq (car lap1) byte-goto-always-pop-ops)
- ;; Always-pop branch taken.
- (byte-compile-log-lap " %s %s\t-->\t%s"
- lap0 lap1
- (cons 'byte-goto (cdr lap1)))
- (setcdr prev (cdr rest)) ; delete const
- (setcar lap1 'byte-goto))
- (t ; -else-pop branch taken: keep const
- (byte-compile-log-lap " %s %s\t-->\t%s %s"
- lap0 lap1
- lap0 (cons 'byte-goto (cdr lap1)))
- (setcar lap1 'byte-goto)
- (setq prev (cdr prev)) ; FIXME: temporary compat hack
- ))
- (setq keep-going t))
- ;;
- ;; varref-X varref-X --> varref-X dup
- ;; varref-X [dup ...] varref-X --> varref-X [dup ...] dup
- ;; stackref-X [dup ...] stackref-X+N --> stackref-X [dup ...] dup
- ;; We don't optimize the const-X variations on this here,
- ;; because that would inhibit some goto optimizations; we
- ;; optimize the const-X case after all other optimizations.
- ;;
- ((and (memq (car lap0) '(byte-varref byte-stack-ref))
- (progn
- (setq tmp (cdr rest))
- (setq tmp2 0)
- (while (eq (car (car tmp)) 'byte-dup)
- (setq tmp2 (1+ tmp2))
- (setq tmp (cdr tmp)))
- t)
- (eq (if (eq 'byte-stack-ref (car lap0))
- (+ tmp2 1 (cdr lap0))
- (cdr lap0))
- (cdr (car tmp)))
- (eq (car lap0) (car (car tmp))))
- (if (memq byte-optimize-log '(t byte))
- (let ((str ""))
- (setq tmp2 (cdr rest))
- (while (not (eq tmp tmp2))
- (setq tmp2 (cdr tmp2)
- str (concat str " dup")))
- (byte-compile-log-lap " %s%s %s\t-->\t%s%s dup"
- lap0 str lap0 lap0 str)))
- (setq keep-going t)
- (setcar (car tmp) 'byte-dup)
- (setcdr (car tmp) 0))
- ;;
- ;; TAG1: TAG2: --> <deleted> TAG2:
- ;; (and other references to TAG1 are replaced with TAG2)
- ;;
- ((and (eq (car lap0) 'TAG)
- (eq (car lap1) 'TAG))
- (byte-compile-log-lap " adjacent tags %d and %d merged"
- (nth 1 lap1) (nth 1 lap0))
- (setq tmp3 (cdr lap-head))
- (while (setq tmp2 (rassq lap0 tmp3))
- (setcdr tmp2 lap1)
- (setq tmp3 (cdr (memq tmp2 tmp3))))
- (setcdr prev (cdr rest))
- (setq keep-going t)
- ;; replace references to tag in jump tables, if any
- (dolist (table byte-compile-jump-tables)
- (maphash #'(lambda (value tag)
- (when (equal tag lap0)
- (puthash value lap1 table)))
- table)))
- ;;
- ;; unused-TAG: --> <deleted>
- ;;
- ((and (eq 'TAG (car lap0))
- (not (rassq lap0 (cdr lap-head)))
- ;; make sure this tag isn't used in a jump-table
- (cl-loop for table in byte-compile-jump-tables
- when (member lap0 (hash-table-values table))
- return nil finally return t))
- (byte-compile-log-lap " unused tag %d removed" (nth 1 lap0))
- (setcdr prev (cdr rest))
- (setq keep-going t))
- ;;
- ;; goto ... --> goto <delete until TAG or end>
- ;; return ... --> return <delete until TAG or end>
- ;;
- ((and (memq (car lap0) '(byte-goto byte-return))
- (not (memq (car lap1) '(TAG nil))))
- (setq tmp rest)
- (let ((i 0)
- (opt-p (memq byte-optimize-log '(t byte)))
- str deleted)
- (while (and (setq tmp (cdr tmp))
- (not (eq 'TAG (car (car tmp)))))
- (if opt-p (setq deleted (cons (car tmp) deleted)
- str (concat str " %s")
- i (1+ i))))
- (if opt-p
- (let ((tagstr
- (if (eq 'TAG (car (car tmp)))
- (format "%d:" (car (cdr (car tmp))))
- (or (car tmp) ""))))
- (if (< i 6)
- (apply 'byte-compile-log-lap-1
- (concat " %s" str
- " %s\t-->\t%s <deleted> %s")
- lap0
- (nconc (nreverse deleted)
- (list tagstr lap0 tagstr)))
- (byte-compile-log-lap
- " %s <%d unreachable op%s> %s\t-->\t%s <deleted> %s"
- lap0 i (if (= i 1) "" "s")
- tagstr lap0 tagstr))))
- (setcdr rest tmp))
- (setq prev rest) ; FIXME: temporary compat hack
- (setq keep-going t))
- ;;
- ;; <safe-op> unbind --> unbind <safe-op>
- ;; (this may enable other optimizations.)
- ;;
- ((and (eq 'byte-unbind (car lap1))
- (memq (car lap0) byte-after-unbind-ops))
- (byte-compile-log-lap " %s %s\t-->\t%s %s" lap0 lap1 lap1 lap0)
- (setcar rest lap1)
- (setcar (cdr rest) lap0)
- (setq keep-going t))
- ;;
- ;; varbind-X unbind-N --> discard unbind-(N-1)
- ;; save-excursion unbind-N --> unbind-(N-1)
- ;; save-restriction unbind-N --> unbind-(N-1)
- ;; save-current-buffer unbind-N --> unbind-(N-1)
- ;;
- ((and (eq 'byte-unbind (car lap1))
- (memq (car lap0) '(byte-varbind byte-save-excursion
- byte-save-restriction
- byte-save-current-buffer))
- (< 0 (cdr lap1)))
- (setcdr lap1 (1- (cdr lap1)))
- (when (zerop (cdr lap1))
- (setcdr rest (cddr rest)))
- (if (eq (car lap0) 'byte-varbind)
- (setcar rest (cons 'byte-discard 0))
- (setcdr prev (cddr prev)))
- (byte-compile-log-lap " %s %s\t-->\t%s %s"
- lap0 (cons (car lap1) (1+ (cdr lap1)))
- (if (eq (car lap0) 'byte-varbind)
- (car rest)
- (car (cdr rest)))
- (if (and (/= 0 (cdr lap1))
- (eq (car lap0) 'byte-varbind))
- (car (cdr rest))
- ""))
- (setq keep-going t))
- ;;
- ;; goto*-X ... X: goto-Y --> goto*-Y
- ;; goto-X ... X: return --> return
- ;;
- ((and (memq (car lap0) byte-goto-ops)
- (memq (car (setq tmp (nth 1 (memq (cdr lap0) (cdr lap-head)))))
- '(byte-goto byte-return))
- (or (eq (car lap0) 'byte-goto)
- (eq (car tmp) 'byte-goto))
- (not (eq (cdr tmp) (cdr lap0))))
- ;; FIXME: inaccurate log message when lap0 = goto-if-*
- (byte-compile-log-lap " %s [%s]\t-->\t%s" (car lap0) tmp tmp)
- (when (eq (car tmp) 'byte-return)
- (setcar lap0 'byte-return))
- (setcdr lap0 (cdr tmp))
- (setq prev (cdr prev)) ; FIXME: temporary compat hack
- (setq keep-going t))
-
- ;;
- ;; OP goto(X) Y: OP X: -> Y: OP X:
- ;;
- ((and (eq (car lap1) 'byte-goto)
- (eq (car lap2) 'TAG)
- (let ((lap3 (nth 3 rest)))
- (and (eq (car lap0) (car lap3))
- (eq (cdr lap0) (cdr lap3))
- (eq (cdr lap1) (nth 4 rest)))))
- (byte-compile-log-lap " %s %s %s %s %s\t-->\t%s %s %s"
- lap0 lap1 lap2
- (nth 3 rest) (nth 4 rest)
- lap2 (nth 3 rest) (nth 4 rest))
- (setcdr prev (cddr rest))
- (setq keep-going t))
-
- ;;
- ;; OP const return --> const return
- ;; where OP is side-effect-free (or mere stack manipulation).
- ;;
- ((and (eq (car lap1) 'byte-constant)
- (eq (car (nth 2 rest)) 'byte-return)
- (or (memq (car lap0) '( byte-discard byte-discardN
- byte-discardN-preserve-tos
- byte-stack-set))
- (memq (car lap0) side-effect-free)))
- (setq keep-going t)
- (setq add-depth 1) ; in case we get rid of too much stack reduction
- (setcdr prev (cdr rest))
- (byte-compile-log-lap " %s %s %s\t-->\t%s %s"
- lap0 lap1 (nth 2 rest) lap1 (nth 2 rest)))
-
- ;;
- ;; goto-*-else-pop X ... X: goto-if-* --> whatever
- ;; goto-*-else-pop X ... X: discard --> whatever
- ;;
- ((and (memq (car lap0) '(byte-goto-if-nil-else-pop
- byte-goto-if-not-nil-else-pop))
- (memq (caar (setq tmp (cdr (memq (cdr lap0) (cdr lap-head)))))
- (eval-when-compile
- (cons 'byte-discard byte-conditional-ops)))
- (not (eq lap0 (car tmp))))
- (setq tmp2 (car tmp))
- (setq tmp3 (assq (car lap0) '((byte-goto-if-nil-else-pop
- byte-goto-if-nil)
- (byte-goto-if-not-nil-else-pop
- byte-goto-if-not-nil))))
- (if (memq (car tmp2) tmp3)
- (progn (setcar lap0 (car tmp2))
- (setcdr lap0 (cdr tmp2))
- (byte-compile-log-lap " %s-else-pop [%s]\t-->\t%s"
- (car lap0) tmp2 lap0))
- ;; Get rid of the -else-pop's and jump one step further.
- (or (eq 'TAG (car (nth 1 tmp)))
- (setcdr tmp (cons (byte-compile-make-tag)
- (cdr tmp))))
- (byte-compile-log-lap " %s [%s]\t-->\t%s <skip>"
- (car lap0) tmp2 (nth 1 tmp3))
- (setcar lap0 (nth 1 tmp3))
- (setcdr lap0 (nth 1 tmp)))
- (setq prev (cdr prev)) ; FIXME: temporary compat hack
- (setq keep-going t))
- ;;
- ;; const goto-X ... X: goto-if-* --> whatever
- ;; const goto-X ... X: discard --> whatever
- ;;
- ((and (eq (car lap0) 'byte-constant)
- (eq (car lap1) 'byte-goto)
- (memq (caar (setq tmp (cdr (memq (cdr lap1) (cdr lap-head)))))
- (eval-when-compile
- (cons 'byte-discard byte-conditional-ops)))
- (not (eq lap1 (car tmp))))
- (setq tmp2 (car tmp))
- (cond ((when (consp (cdr lap0))
- (memq (car tmp2)
- (if (null (car (cdr lap0)))
- '(byte-goto-if-nil byte-goto-if-nil-else-pop)
- '(byte-goto-if-not-nil
- byte-goto-if-not-nil-else-pop))))
- (byte-compile-log-lap " %s goto [%s]\t-->\t%s %s"
- lap0 tmp2 lap0 tmp2)
- (setcar lap1 (car tmp2))
- (setcdr lap1 (cdr tmp2))
- ;; Let next step fix the (const,goto-if*) sequence.
- (setq keep-going t))
- ((or (consp (cdr lap0))
- (eq (car tmp2) 'byte-discard))
- ;; Jump one step further
- (byte-compile-log-lap
- " %s goto [%s]\t-->\t<deleted> goto <skip>"
- lap0 tmp2)
- (or (eq 'TAG (car (nth 1 tmp)))
- (setcdr tmp (cons (byte-compile-make-tag)
- (cdr tmp))))
- (setcdr lap1 (car (cdr tmp)))
- (setcdr prev (cdr rest))
- (setq keep-going t))
- (t
- (setq prev (cdr prev)))))
- ;;
- ;; X: varref-Y ... varset-Y goto-X -->
- ;; X: varref-Y Z: ... dup varset-Y goto-Z
- ;; (varset-X goto-BACK, BACK: varref-X --> copy the varref down.)
- ;; (This is so usual for while loops that it is worth handling).
- ;;
- ;; Here again, we could do it for stack-ref/stack-set, but
- ;; that's replacing a stack-ref-Y with a stack-ref-0, which
- ;; is a very minor improvement (if any), at the cost of
- ;; more stack use and more byte-code. Let's not do it.
- ;;
- ((and (eq (car lap1) 'byte-varset)
- (eq (car lap2) 'byte-goto)
- (not (memq (cdr lap2) rest)) ;Backwards jump
- (eq (car (car (setq tmp (cdr (memq (cdr lap2) (cdr lap-head))))))
- 'byte-varref)
- (eq (cdr (car tmp)) (cdr lap1))
- (not (memq (car (cdr lap1)) byte-boolean-vars)))
- ;;(byte-compile-log-lap " Pulled %s to end of loop" (car tmp))
- (let ((newtag (byte-compile-make-tag)))
- (byte-compile-log-lap
- " %s: %s ... %s %s\t-->\t%s: %s %s: ... %s %s %s"
- (nth 1 (cdr lap2)) (car tmp)
- lap1 lap2
- (nth 1 (cdr lap2)) (car tmp)
- (nth 1 newtag) 'byte-dup lap1
- (cons 'byte-goto newtag)
- )
- (setcdr rest (cons (cons 'byte-dup 0) (cdr rest)))
- (setcdr tmp (cons (setcdr lap2 newtag) (cdr tmp))))
- (setq add-depth 1)
- (setq keep-going t))
- ;;
- ;; goto-X Y: ... X: goto-if*-Y --> goto-if-not-*-X+1 Y:
- ;; (This can pull the loop test to the end of the loop)
- ;;
- ((and (eq (car lap0) 'byte-goto)
- (eq (car lap1) 'TAG)
- (eq lap1
- (cdar (setq tmp (cdr (memq (cdr lap0) (cdr lap-head))))))
- (memq (car (car tmp))
- '(byte-goto byte-goto-if-nil byte-goto-if-not-nil
- byte-goto-if-nil-else-pop)))
- (let ((newtag (byte-compile-make-tag)))
- (byte-compile-log-lap
- " %s %s ... %s %s\t-->\t%s ... %s"
- lap0 lap1 (cdr lap0) (car tmp)
- (cons (cdr (assq (car (car tmp))
- '((byte-goto-if-nil . byte-goto-if-not-nil)
- (byte-goto-if-not-nil . byte-goto-if-nil)
- (byte-goto-if-nil-else-pop .
- byte-goto-if-not-nil-else-pop)
- (byte-goto-if-not-nil-else-pop .
- byte-goto-if-nil-else-pop))))
- newtag)
-
- newtag)
- (setcdr tmp (cons (setcdr lap0 newtag) (cdr tmp)))
- (if (eq (car (car tmp)) 'byte-goto-if-nil-else-pop)
- ;; We can handle this case but not the -if-not-nil case,
- ;; because we won't know which non-nil constant to push.
- (setcdr rest (cons (cons 'byte-constant
- (byte-compile-get-constant nil))
- (cdr rest))))
- (setcar lap0 (nth 1 (memq (car (car tmp))
- '(byte-goto-if-nil-else-pop
- byte-goto-if-not-nil
- byte-goto-if-nil
- byte-goto-if-not-nil
- byte-goto byte-goto))))
- )
- (setq keep-going t))
-
- ;;
- ;; discardN-preserve-tos(X) discardN-preserve-tos(Y)
- ;; --> discardN-preserve-tos(X+Y)
- ;; where stack-set(1) is accepted as discardN-preserve-tos(1)
- ;;
- ((and (or (eq (car lap0) 'byte-discardN-preserve-tos)
- (and (eq (car lap0) 'byte-stack-set) (eql (cdr lap0) 1)))
- (or (eq (car lap1) 'byte-discardN-preserve-tos)
- (and (eq (car lap1) 'byte-stack-set) (eql (cdr lap1) 1))))
- (setq keep-going t)
- (let ((new-op (cons 'byte-discardN-preserve-tos
- ;; This happens to work even when either
- ;; op is stack-set(1).
- (+ (cdr lap0) (cdr lap1)))))
- (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 new-op)
- (setcar rest new-op)
- (setcdr rest (cddr rest))
- (setq prev rest) ; FIXME: temporary compat hack
- ))
-
- ;;
- ;; stack-set-M [discard/discardN ...] --> discardN-preserve-tos
- ;; stack-set-M [discard/discardN ...] --> discardN
- ;;
- ((and (eq (car lap0) 'byte-stack-set)
- (memq (car lap1) '(byte-discard byte-discardN))
- (progn
- ;; See if enough discard operations follow to expose or
- ;; destroy the value stored by the stack-set.
- (setq tmp (cdr rest))
- (setq tmp2 (1- (cdr lap0)))
- (setq tmp3 0)
- (while (memq (car (car tmp)) '(byte-discard byte-discardN))
- (setq tmp3
- (+ tmp3 (if (eq (car (car tmp)) 'byte-discard)
- 1
- (cdr (car tmp)))))
- (setq tmp (cdr tmp)))
- (>= tmp3 tmp2)))
- ;; Do the optimization.
- (setcdr prev (cdr rest))
- (setcar lap1
- (if (= tmp2 tmp3)
- ;; The value stored is the new TOS, so pop one more
- ;; value (to get rid of the old value) using the
- ;; TOS-preserving discard operator.
- 'byte-discardN-preserve-tos
- ;; Otherwise, the value stored is lost, so just use a
- ;; normal discard.
- 'byte-discardN))
- (setcdr lap1 (1+ tmp3))
- (setcdr (cdr rest) tmp)
- (byte-compile-log-lap " %s [discard/discardN]...\t-->\t%s"
- lap0 lap1)
- ;; FIXME: shouldn't we do (setq keep-going t) here?
- )
-
- ;;
- ;; discardN-preserve-tos return --> return
- ;; dup return --> return
- ;; stack-set(1) return --> return
- ;;
- ((and (eq (car lap1) 'byte-return)
- (or (memq (car lap0) '(byte-discardN-preserve-tos byte-dup))
- (and (eq (car lap0) 'byte-stack-set)
- (= (cdr lap0) 1))))
- (setq keep-going t)
- ;; The byte-code interpreter will pop the stack for us, so
- ;; we can just leave stuff on it.
- (setcdr prev (cdr rest))
- (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 lap1))
-
- ;;
- ;; goto-X ... X: discard ==> discard goto-Y ... X: discard Y:
- ;;
- ((and (eq (car lap0) 'byte-goto)
- (setq tmp (cdr (memq (cdr lap0) (cdr lap-head))))
- (or (memq (caar tmp) '(byte-discard byte-discardN))
- ;; Make sure we don't hoist a discardN-preserve-tos
- ;; that really should be merged or deleted instead.
- (and (eq (caar tmp) 'byte-discardN-preserve-tos)
- (let ((next (cadr tmp)))
- (not (or (memq (car next) '(byte-discardN-preserve-tos
- byte-return))
- (and (eq (car next) 'byte-stack-set)
- (eql (cdr next) 1))))))))
- (byte-compile-log-lap
- " goto-X .. X: \t-->\t%s goto-X.. X: %s Y:"
- (car tmp) (car tmp))
- (setq keep-going t)
- (let* ((newtag (byte-compile-make-tag))
- ;; Make a copy, since we sometimes modify insts in-place!
- (newdiscard (cons (caar tmp) (cdar tmp)))
- (newjmp (cons (car lap0) newtag)))
- (push newtag (cdr tmp)) ;Push new tag after the discard.
- (setcar rest newdiscard)
- (push newjmp (cdr rest))))
-
- ;;
- ;; const discardN-preserve-tos ==> discardN const
- ;; const stack-set(1) ==> discard const
- ;;
- ((and (eq (car lap0) 'byte-constant)
- (or (eq (car lap1) 'byte-discardN-preserve-tos)
- (and (eq (car lap1) 'byte-stack-set)
- (eql (cdr lap1) 1))))
- (setq keep-going t)
- (let ((newdiscard (if (eql (cdr lap1) 1)
- (cons 'byte-discard nil)
- (cons 'byte-discardN (cdr lap1)))))
- (byte-compile-log-lap
- " %s %s\t-->\t%s %s" lap0 lap1 newdiscard lap0)
- (setf (car rest) newdiscard)
- (setf (cadr rest) lap0))
- (setq prev (cdr prev)) ; FIXME: temporary compat hack
- )
- (t
- ;; If no rule matched, advance and try again.
- (setq prev (cdr prev))))))
+ (cons 'byte-discardN (cdr lap1)))))
+ (byte-compile-log-lap
+ " %s %s\t-->\t%s %s" lap0 lap1 newdiscard lap0)
+ (setf (car rest) newdiscard)
+ (setf (cadr rest) lap0))
+ (setq prev (cdr prev)) ; FIXME: temporary compat hack
+ )
+ (t
+ ;; If no rule matched, advance and try again.
+ (setq prev (cdr prev))))))))
;; Cleanup stage:
;; Rebuild byte-compile-constants / byte-compile-variables.
;; Simple optimizations that would inhibit other optimizations if they
;; need to do more than once.
(setq byte-compile-constants nil
byte-compile-variables nil)
- (setq prev lap-head)
(byte-compile-log-lap " ---- final pass")
- (while (cdr prev)
- (setq rest (cdr prev))
- (setq lap0 (car rest)
- lap1 (nth 1 rest))
- ;; FIXME: Would there ever be a `byte-constant2' op here?
- (if (memq (car lap0) byte-constref-ops)
- (if (memq (car lap0) '(byte-constant byte-constant2))
- (unless (memq (cdr lap0) byte-compile-constants)
- (setq byte-compile-constants (cons (cdr lap0)
- byte-compile-constants)))
- (unless (memq (cdr lap0) byte-compile-variables)
- (setq byte-compile-variables (cons (cdr lap0)
- byte-compile-variables)))))
- (cond (;;
- ;; const-C varset-X const-C --> const-C dup varset-X
- ;; const-C varbind-X const-C --> const-C dup varbind-X
- ;;
- (and (eq (car lap0) 'byte-constant)
- (eq (car (nth 2 rest)) 'byte-constant)
- (eq (cdr lap0) (cdr (nth 2 rest)))
- (memq (car lap1) '(byte-varbind byte-varset)))
- (byte-compile-log-lap " %s %s %s\t-->\t%s dup %s"
- lap0 lap1 lap0 lap0 lap1)
- (setcar (cdr (cdr rest)) (cons (car lap1) (cdr lap1)))
- (setcar (cdr rest) (cons 'byte-dup 0))
- (setq add-depth 1))
- ;;
- ;; const-X [dup/const-X ...] --> const-X [dup ...] dup
- ;; varref-X [dup/varref-X ...] --> varref-X [dup ...] dup
- ;;
- ((memq (car lap0) '(byte-constant byte-varref))
- (setq tmp rest
- tmp2 nil)
- (while (progn
- (while (eq 'byte-dup (car (car (setq tmp (cdr tmp))))))
- (and (eq (cdr lap0) (cdr (car tmp)))
- (eq (car lap0) (car (car tmp)))))
- (setcar tmp (cons 'byte-dup 0))
- (setq tmp2 t))
- (if tmp2
- (byte-compile-log-lap
- " %s [dup/%s]...\t-->\t%s dup..." lap0 lap0 lap0)
- (setq prev (cdr prev))))
- ;;
- ;; unbind-N unbind-M --> unbind-(N+M)
- ;;
- ((and (eq 'byte-unbind (car lap0))
- (eq 'byte-unbind (car lap1)))
- (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1
- (cons 'byte-unbind
- (+ (cdr lap0) (cdr lap1))))
- (setcdr prev (cdr rest))
- (setcdr lap1 (+ (cdr lap1) (cdr lap0))))
-
- ;;
- ;; discard/discardN/discardN-preserve-tos-X discard/discardN-Y -->
- ;; discardN-(X+Y)
- ;;
- ((and (memq (car lap0)
- '(byte-discard byte-discardN
- byte-discardN-preserve-tos))
- (memq (car lap1) '(byte-discard byte-discardN)))
- (setcdr prev (cdr rest))
- (byte-compile-log-lap
- " %s %s\t-->\t(discardN %s)"
- lap0 lap1
- (+ (if (eq (car lap0) 'byte-discard) 1 (cdr lap0))
- (if (eq (car lap1) 'byte-discard) 1 (cdr lap1))))
- (setcdr lap1 (+ (if (eq (car lap0) 'byte-discard) 1 (cdr lap0))
- (if (eq (car lap1) 'byte-discard) 1 (cdr lap1))))
- (setcar lap1 'byte-discardN))
- (t
- (setq prev (cdr prev)))))
+ (let ((prev lap-head))
+ (while (cdr prev)
+ (let* ((rest (cdr prev))
+ (lap0 (car rest))
+ (lap1 (nth 1 rest)))
+ ;; FIXME: Would there ever be a `byte-constant2' op here?
+ (if (memq (car lap0) byte-constref-ops)
+ (if (memq (car lap0) '(byte-constant byte-constant2))
+ (unless (memq (cdr lap0) byte-compile-constants)
+ (setq byte-compile-constants (cons (cdr lap0)
+ byte-compile-constants)))
+ (unless (memq (cdr lap0) byte-compile-variables)
+ (setq byte-compile-variables (cons (cdr lap0)
+ byte-compile-variables)))))
+ (cond
+ ;;
+ ;; const-C varset-X const-C --> const-C dup varset-X
+ ;; const-C varbind-X const-C --> const-C dup varbind-X
+ ;;
+ ((and (eq (car lap0) 'byte-constant)
+ (eq (car (nth 2 rest)) 'byte-constant)
+ (eq (cdr lap0) (cdr (nth 2 rest)))
+ (memq (car lap1) '(byte-varbind byte-varset)))
+ (byte-compile-log-lap " %s %s %s\t-->\t%s dup %s"
+ lap0 lap1 lap0 lap0 lap1)
+ (setcar (cdr (cdr rest)) (cons (car lap1) (cdr lap1)))
+ (setcar (cdr rest) (cons 'byte-dup 0))
+ (setq add-depth 1))
+ ;;
+ ;; const-X [dup/const-X ...] --> const-X [dup ...] dup
+ ;; varref-X [dup/varref-X ...] --> varref-X [dup ...] dup
+ ;;
+ ((memq (car lap0) '(byte-constant byte-varref))
+ (let ((tmp rest)
+ (tmp2 nil))
+ (while (progn
+ (while (eq 'byte-dup (car (car (setq tmp (cdr tmp))))))
+ (and (eq (cdr lap0) (cdr (car tmp)))
+ (eq (car lap0) (car (car tmp)))))
+ (setcar tmp (cons 'byte-dup 0))
+ (setq tmp2 t))
+ (if tmp2
+ (byte-compile-log-lap
+ " %s [dup/%s]...\t-->\t%s dup..." lap0 lap0 lap0)
+ (setq prev (cdr prev)))))
+ ;;
+ ;; unbind-N unbind-M --> unbind-(N+M)
+ ;;
+ ((and (eq 'byte-unbind (car lap0))
+ (eq 'byte-unbind (car lap1)))
+ (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1
+ (cons 'byte-unbind
+ (+ (cdr lap0) (cdr lap1))))
+ (setcdr prev (cdr rest))
+ (setcdr lap1 (+ (cdr lap1) (cdr lap0))))
+
+ ;;
+ ;; discard/discardN/discardN-preserve-tos-X discard/discardN-Y -->
+ ;; discardN-(X+Y)
+ ;;
+ ((and (memq (car lap0)
+ '(byte-discard byte-discardN
+ byte-discardN-preserve-tos))
+ (memq (car lap1) '(byte-discard byte-discardN)))
+ (setcdr prev (cdr rest))
+ (byte-compile-log-lap
+ " %s %s\t-->\t(discardN %s)"
+ lap0 lap1
+ (+ (if (eq (car lap0) 'byte-discard) 1 (cdr lap0))
+ (if (eq (car lap1) 'byte-discard) 1 (cdr lap1))))
+ (setcdr lap1 (+ (if (eq (car lap0) 'byte-discard) 1 (cdr lap0))
+ (if (eq (car lap1) 'byte-discard) 1 (cdr lap1))))
+ (setcar lap1 'byte-discardN))
+ (t
+ (setq prev (cdr prev)))))))
(setq byte-compile-maxdepth (+ byte-compile-maxdepth add-depth))
(cdr lap-head)))
projects / emacs.git / commitdiff