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Diffstat (limited to 'lisp/emacs-lisp/byte-opt.el')
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diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el deleted file mode 100644 index ef2880c7d9b..00000000000 --- a/lisp/emacs-lisp/byte-opt.el +++ /dev/null @@ -1,1872 +0,0 @@ -;;; byte-opt.el --- the optimization passes of the emacs-lisp byte compiler. - -;;; Copyright (c) 1991, 1994 Free Software Foundation, Inc. - -;; Author: Jamie Zawinski <jwz@lucid.com> -;; Hallvard Furuseth <hbf@ulrik.uio.no> -;; Keywords: internal - -;; This file is part of GNU Emacs. - -;; GNU Emacs is free software; you can redistribute it and/or modify -;; it under the terms of the GNU General Public License as published by -;; the Free Software Foundation; either version 2, or (at your option) -;; any later version. - -;; GNU Emacs is distributed in the hope that it will be useful, -;; but WITHOUT ANY WARRANTY; without even the implied warranty of -;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -;; GNU General Public License for more details. - -;; You should have received a copy of the GNU General Public License -;; along with GNU Emacs; see the file COPYING. If not, write to the -;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, -;; Boston, MA 02111-1307, USA. - -;;; Commentary: - -;;; This file has been censored by the Communications Decency Act. -;;; That law was passed under the guise of a ban on pornography, but -;;; it bans far more than that. This file did not contain pornography, -;;; but it was censored nonetheless. - -;;; For information on US government censorship of the Internet, and -;;; what you can do to bring back freedom of the press, see the web -;;; site http://www.vtw.org/ - -;; ======================================================================== -;; "No matter how hard you try, you can't make a racehorse out of a pig. -;; You can, however, make a faster pig." -;; -;; Or, to put it another way, the emacs byte compiler is a VW Bug. This code -;; makes it be a VW Bug with fuel injection and a turbocharger... You're -;; still not going to make it go faster than 70 mph, but it might be easier -;; to get it there. -;; - -;; TO DO: -;; -;; (apply '(lambda (x &rest y) ...) 1 (foo)) -;; -;; maintain a list of functions known not to access any global variables -;; (actually, give them a 'dynamically-safe property) and then -;; (let ( v1 v2 ... vM vN ) <...dynamically-safe...> ) ==> -;; (let ( v1 v2 ... vM ) vN <...dynamically-safe...> ) -;; by recursing on this, we might be able to eliminate the entire let. -;; However certain variables should never have their bindings optimized -;; away, because they affect everything. -;; (put 'debug-on-error 'binding-is-magic t) -;; (put 'debug-on-abort 'binding-is-magic t) -;; (put 'debug-on-next-call 'binding-is-magic t) -;; (put 'mocklisp-arguments 'binding-is-magic t) -;; (put 'inhibit-quit 'binding-is-magic t) -;; (put 'quit-flag 'binding-is-magic t) -;; (put 't 'binding-is-magic t) -;; (put 'nil 'binding-is-magic t) -;; possibly also -;; (put 'gc-cons-threshold 'binding-is-magic t) -;; (put 'track-mouse 'binding-is-magic t) -;; others? -;; -;; Simple defsubsts often produce forms like -;; (let ((v1 (f1)) (v2 (f2)) ...) -;; (FN v1 v2 ...)) -;; It would be nice if we could optimize this to -;; (FN (f1) (f2) ...) -;; but we can't unless FN is dynamically-safe (it might be dynamically -;; referring to the bindings that the lambda arglist established.) -;; One of the uncountable lossages introduced by dynamic scope... -;; -;; Maybe there should be a control-structure that says "turn on -;; fast-and-loose type-assumptive optimizations here." Then when -;; we see a form like (car foo) we can from then on assume that -;; the variable foo is of type cons, and optimize based on that. -;; But, this won't win much because of (you guessed it) dynamic -;; scope. Anything down the stack could change the value. -;; (Another reason it doesn't work is that it is perfectly valid -;; to call car with a null argument.) A better approach might -;; be to allow type-specification of the form -;; (put 'foo 'arg-types '(float (list integer) dynamic)) -;; (put 'foo 'result-type 'bool) -;; It should be possible to have these types checked to a certain -;; degree. -;; -;; collapse common subexpressions -;; -;; It would be nice if redundant sequences could be factored out as well, -;; when they are known to have no side-effects: -;; (list (+ a b c) (+ a b c)) --> a b add c add dup list-2 -;; but beware of traps like -;; (cons (list x y) (list x y)) -;; -;; Tail-recursion elimination is not really possible in Emacs Lisp. -;; Tail-recursion elimination is almost always impossible when all variables -;; have dynamic scope, but given that the "return" byteop requires the -;; binding stack to be empty (rather than emptying it itself), there can be -;; no truly tail-recursive Emacs Lisp functions that take any arguments or -;; make any bindings. -;; -;; Here is an example of an Emacs Lisp function which could safely be -;; byte-compiled tail-recursively: -;; -;; (defun tail-map (fn list) -;; (cond (list -;; (funcall fn (car list)) -;; (tail-map fn (cdr list))))) -;; -;; However, if there was even a single let-binding around the COND, -;; it could not be byte-compiled, because there would be an "unbind" -;; byte-op between the final "call" and "return." Adding a -;; Bunbind_all byteop would fix this. -;; -;; (defun foo (x y z) ... (foo a b c)) -;; ... (const foo) (varref a) (varref b) (varref c) (call 3) END: (return) -;; ... (varref a) (varbind x) (varref b) (varbind y) (varref c) (varbind z) (goto 0) END: (unbind-all) (return) -;; ... (varref a) (varset x) (varref b) (varset y) (varref c) (varset z) (goto 0) END: (return) -;; -;; this also can be considered tail recursion: -;; -;; ... (const foo) (varref a) (call 1) (goto X) ... X: (return) -;; could generalize this by doing the optimization -;; (goto X) ... X: (return) --> (return) -;; -;; But this doesn't solve all of the problems: although by doing tail- -;; recursion elimination in this way, the call-stack does not grow, the -;; binding-stack would grow with each recursive step, and would eventually -;; overflow. I don't believe there is any way around this without lexical -;; scope. -;; -;; Wouldn't it be nice if Emacs Lisp had lexical scope. -;; -;; Idea: the form (lexical-scope) in a file means that the file may be -;; compiled lexically. This proclamation is file-local. Then, within -;; that file, "let" would establish lexical bindings, and "let-dynamic" -;; would do things the old way. (Or we could use CL "declare" forms.) -;; We'd have to notice defvars and defconsts, since those variables should -;; always be dynamic, and attempting to do a lexical binding of them -;; should simply do a dynamic binding instead. -;; But! We need to know about variables that were not necessarily defvarred -;; in the file being compiled (doing a boundp check isn't good enough.) -;; Fdefvar() would have to be modified to add something to the plist. -;; -;; A major disadvantage of this scheme is that the interpreter and compiler -;; would have different semantics for files compiled with (dynamic-scope). -;; Since this would be a file-local optimization, there would be no way to -;; modify the interpreter to obey this (unless the loader was hacked -;; in some grody way, but that's a really bad idea.) - -;; Other things to consider: - -;;;;; Associative math should recognize subcalls to identical function: -;;;(disassemble (lambda (x) (+ (+ (foo) 1) (+ (bar) 2)))) -;;;;; This should generate the same as (1+ x) and (1- x) - -;;;(disassemble (lambda (x) (cons (+ x 1) (- x 1)))) -;;;;; An awful lot of functions always return a non-nil value. If they're -;;;;; error free also they may act as true-constants. - -;;;(disassemble (lambda (x) (and (point) (foo)))) -;;;;; When -;;;;; - all but one arguments to a function are constant -;;;;; - the non-constant argument is an if-expression (cond-expression?) -;;;;; then the outer function can be distributed. If the guarding -;;;;; condition is side-effect-free [assignment-free] then the other -;;;;; arguments may be any expressions. Since, however, the code size -;;;;; can increase this way they should be "simple". Compare: - -;;;(disassemble (lambda (x) (eq (if (point) 'a 'b) 'c))) -;;;(disassemble (lambda (x) (if (point) (eq 'a 'c) (eq 'b 'c)))) - -;;;;; (car (cons A B)) -> (progn B A) -;;;(disassemble (lambda (x) (car (cons (foo) 42)))) - -;;;;; (cdr (cons A B)) -> (progn A B) -;;;(disassemble (lambda (x) (cdr (cons 42 (foo))))) - -;;;;; (car (list A B ...)) -> (progn B ... A) -;;;(disassemble (lambda (x) (car (list (foo) 42 (bar))))) - -;;;;; (cdr (list A B ...)) -> (progn A (list B ...)) -;;;(disassemble (lambda (x) (cdr (list 42 (foo) (bar))))) - - -;;; Code: - -(defun byte-compile-log-lap-1 (format &rest args) - (if (aref byte-code-vector 0) - (error "The old version of the disassembler is loaded. Reload new-bytecomp as well.")) - (byte-compile-log-1 - (apply 'format format - (let (c a) - (mapcar '(lambda (arg) - (if (not (consp arg)) - (if (and (symbolp arg) - (string-match "^byte-" (symbol-name arg))) - (intern (substring (symbol-name arg) 5)) - arg) - (if (integerp (setq c (car arg))) - (error "non-symbolic byte-op %s" c)) - (if (eq c 'TAG) - (setq c arg) - (setq a (cond ((memq c byte-goto-ops) - (car (cdr (cdr arg)))) - ((memq c byte-constref-ops) - (car (cdr arg))) - (t (cdr arg)))) - (setq c (symbol-name c)) - (if (string-match "^byte-." c) - (setq c (intern (substring c 5))))) - (if (eq c 'constant) (setq c 'const)) - (if (and (eq (cdr arg) 0) - (not (memq c '(unbind call const)))) - c - (format "(%s %s)" c a)))) - args))))) - -(defmacro byte-compile-log-lap (format-string &rest args) - (list 'and - '(memq byte-optimize-log '(t byte)) - (cons 'byte-compile-log-lap-1 - (cons format-string args)))) - - -;;; byte-compile optimizers to support inlining - -(put 'inline 'byte-optimizer 'byte-optimize-inline-handler) - -(defun byte-optimize-inline-handler (form) - "byte-optimize-handler for the `inline' special-form." - (cons 'progn - (mapcar - '(lambda (sexp) - (let ((fn (car-safe sexp))) - (if (and (symbolp fn) - (or (cdr (assq fn byte-compile-function-environment)) - (and (fboundp fn) - (not (or (cdr (assq fn byte-compile-macro-environment)) - (and (consp (setq fn (symbol-function fn))) - (eq (car fn) 'macro)) - (subrp fn)))))) - (byte-compile-inline-expand sexp) - sexp))) - (cdr form)))) - - -;; Splice the given lap code into the current instruction stream. -;; If it has any labels in it, you're responsible for making sure there -;; are no collisions, and that byte-compile-tag-number is reasonable -;; after this is spliced in. The provided list is destroyed. -(defun byte-inline-lapcode (lap) - (setq byte-compile-output (nconc (nreverse lap) byte-compile-output))) - - -(defun byte-compile-inline-expand (form) - (let* ((name (car form)) - (fn (or (cdr (assq name byte-compile-function-environment)) - (and (fboundp name) (symbol-function name))))) - (if (null fn) - (progn - (byte-compile-warn "attempt to inline %s before it was defined" name) - form) - ;; else - (if (and (consp fn) (eq (car fn) 'autoload)) - (load (nth 1 fn))) - (if (and (consp fn) (eq (car fn) 'autoload)) - (error "file \"%s\" didn't define \"%s\"" (nth 1 fn) name)) - (if (symbolp fn) - (byte-compile-inline-expand (cons fn (cdr form))) - (if (byte-code-function-p fn) - (progn - (fetch-bytecode fn) - (cons (list 'lambda (aref fn 0) - (list 'byte-code (aref fn 1) (aref fn 2) (aref fn 3))) - (cdr form))) - (if (not (eq (car fn) 'lambda)) (error "%s is not a lambda" name)) - (cons fn (cdr form))))))) - -;;; ((lambda ...) ...) -;;; -(defun byte-compile-unfold-lambda (form &optional name) - (or name (setq name "anonymous lambda")) - (let ((lambda (car form)) - (values (cdr form))) - (if (byte-code-function-p lambda) - (setq lambda (list 'lambda (aref lambda 0) - (list 'byte-code (aref lambda 1) - (aref lambda 2) (aref lambda 3))))) - (let ((arglist (nth 1 lambda)) - (body (cdr (cdr lambda))) - optionalp restp - bindings) - (if (and (stringp (car body)) (cdr body)) - (setq body (cdr body))) - (if (and (consp (car body)) (eq 'interactive (car (car body)))) - (setq body (cdr body))) - (while arglist - (cond ((eq (car arglist) '&optional) - ;; ok, I'll let this slide because funcall_lambda() does... - ;; (if optionalp (error "multiple &optional keywords in %s" name)) - (if restp (error "&optional found after &rest in %s" name)) - (if (null (cdr arglist)) - (error "nothing after &optional in %s" name)) - (setq optionalp t)) - ((eq (car arglist) '&rest) - ;; ...but it is by no stretch of the imagination a reasonable - ;; thing that funcall_lambda() allows (&rest x y) and - ;; (&rest x &optional y) in arglists. - (if (null (cdr arglist)) - (error "nothing after &rest in %s" name)) - (if (cdr (cdr arglist)) - (error "multiple vars after &rest in %s" name)) - (setq restp t)) - (restp - (setq bindings (cons (list (car arglist) - (and values (cons 'list values))) - bindings) - values nil)) - ((and (not optionalp) (null values)) - (byte-compile-warn "attempt to open-code %s with too few arguments" name) - (setq arglist nil values 'too-few)) - (t - (setq bindings (cons (list (car arglist) (car values)) - bindings) - values (cdr values)))) - (setq arglist (cdr arglist))) - (if values - (progn - (or (eq values 'too-few) - (byte-compile-warn - "attempt to open-code %s with too many arguments" name)) - form) - (setq body (mapcar 'byte-optimize-form body)) - (let ((newform - (if bindings - (cons 'let (cons (nreverse bindings) body)) - (cons 'progn body)))) - (byte-compile-log " %s\t==>\t%s" form newform) - newform))))) - - -;;; implementing source-level optimizers - -(defun byte-optimize-form-code-walker (form for-effect) - ;; - ;; For normal function calls, We can just mapcar the optimizer the cdr. But - ;; we need to have special knowledge of the syntax of the special forms - ;; like let and defun (that's why they're special forms :-). (Actually, - ;; the important aspect is that they are subrs that don't evaluate all of - ;; their args.) - ;; - (let ((fn (car-safe form)) - tmp) - (cond ((not (consp form)) - (if (not (and for-effect - (or byte-compile-delete-errors - (not (symbolp form)) - (eq form t)))) - form)) - ((eq fn 'quote) - (if (cdr (cdr form)) - (byte-compile-warn "malformed quote form: %s" - (prin1-to-string form))) - ;; map (quote nil) to nil to simplify optimizer logic. - ;; map quoted constants to nil if for-effect (just because). - (and (nth 1 form) - (not for-effect) - form)) - ((or (byte-code-function-p fn) - (eq 'lambda (car-safe fn))) - (byte-compile-unfold-lambda form)) - ((memq fn '(let let*)) - ;; recursively enter the optimizer for the bindings and body - ;; of a let or let*. This for depth-firstness: forms that - ;; are more deeply nested are optimized first. - (cons fn - (cons - (mapcar '(lambda (binding) - (if (symbolp binding) - binding - (if (cdr (cdr binding)) - (byte-compile-warn "malformed let binding: %s" - (prin1-to-string binding))) - (list (car binding) - (byte-optimize-form (nth 1 binding) nil)))) - (nth 1 form)) - (byte-optimize-body (cdr (cdr form)) for-effect)))) - ((eq fn 'cond) - (cons fn - (mapcar '(lambda (clause) - (if (consp clause) - (cons - (byte-optimize-form (car clause) nil) - (byte-optimize-body (cdr clause) for-effect)) - (byte-compile-warn "malformed cond form: %s" - (prin1-to-string clause)) - clause)) - (cdr form)))) - ((eq fn 'progn) - ;; as an extra added bonus, this simplifies (progn <x>) --> <x> - (if (cdr (cdr form)) - (progn - (setq tmp (byte-optimize-body (cdr form) for-effect)) - (if (cdr tmp) (cons 'progn tmp) (car tmp))) - (byte-optimize-form (nth 1 form) for-effect))) - ((eq fn 'prog1) - (if (cdr (cdr form)) - (cons 'prog1 - (cons (byte-optimize-form (nth 1 form) for-effect) - (byte-optimize-body (cdr (cdr form)) t))) - (byte-optimize-form (nth 1 form) for-effect))) - ((eq fn 'prog2) - (cons 'prog2 - (cons (byte-optimize-form (nth 1 form) t) - (cons (byte-optimize-form (nth 2 form) for-effect) - (byte-optimize-body (cdr (cdr (cdr form))) t))))) - - ((memq fn '(save-excursion save-restriction save-current-buffer)) - ;; those subrs which have an implicit progn; it's not quite good - ;; enough to treat these like normal function calls. - ;; This can turn (save-excursion ...) into (save-excursion) which - ;; will be optimized away in the lap-optimize pass. - (cons fn (byte-optimize-body (cdr form) for-effect))) - - ((eq fn 'with-output-to-temp-buffer) - ;; this is just like the above, except for the first argument. - (cons fn - (cons - (byte-optimize-form (nth 1 form) nil) - (byte-optimize-body (cdr (cdr form)) for-effect)))) - - ((eq fn 'if) - (cons fn - (cons (byte-optimize-form (nth 1 form) nil) - (cons - (byte-optimize-form (nth 2 form) for-effect) - (byte-optimize-body (nthcdr 3 form) for-effect))))) - - ((memq fn '(and or)) ; remember, and/or are control structures. - ;; take forms off the back until we can't any more. - ;; In the future it could conceivably be a problem that the - ;; subexpressions of these forms are optimized in the reverse - ;; order, but it's ok for now. - (if for-effect - (let ((backwards (reverse (cdr form)))) - (while (and backwards - (null (setcar backwards - (byte-optimize-form (car backwards) - for-effect)))) - (setq backwards (cdr backwards))) - (if (and (cdr form) (null backwards)) - (byte-compile-log - " all subforms of %s called for effect; deleted" form)) - (and backwards - (cons fn (nreverse backwards)))) - (cons fn (mapcar 'byte-optimize-form (cdr form))))) - - ((eq fn 'interactive) - (byte-compile-warn "misplaced interactive spec: %s" - (prin1-to-string form)) - nil) - - ((memq fn '(defun defmacro function - condition-case save-window-excursion)) - ;; These forms are compiled as constants or by breaking out - ;; all the subexpressions and compiling them separately. - form) - - ((eq fn 'unwind-protect) - ;; the "protected" part of an unwind-protect is compiled (and thus - ;; optimized) as a top-level form, so don't do it here. But the - ;; non-protected part has the same for-effect status as the - ;; unwind-protect itself. (The protected part is always for effect, - ;; but that isn't handled properly yet.) - (cons fn - (cons (byte-optimize-form (nth 1 form) for-effect) - (cdr (cdr form))))) - - ((eq fn 'catch) - ;; the body of a catch is compiled (and thus optimized) as a - ;; top-level form, so don't do it here. The tag is never - ;; for-effect. The body should have the same for-effect status - ;; as the catch form itself, but that isn't handled properly yet. - (cons fn - (cons (byte-optimize-form (nth 1 form) nil) - (cdr (cdr form))))) - - ;; If optimization is on, this is the only place that macros are - ;; expanded. If optimization is off, then macroexpansion happens - ;; in byte-compile-form. Otherwise, the macros are already expanded - ;; by the time that is reached. - ((not (eq form - (setq form (macroexpand form - byte-compile-macro-environment)))) - (byte-optimize-form form for-effect)) - - ((not (symbolp fn)) - (or (eq 'mocklisp (car-safe fn)) ; ha! - (byte-compile-warn "%s is a malformed function" - (prin1-to-string fn))) - form) - - ((and for-effect (setq tmp (get fn 'side-effect-free)) - (or byte-compile-delete-errors - (eq tmp 'error-free) - (progn - (byte-compile-warn "%s called for effect" - (prin1-to-string form)) - nil))) - (byte-compile-log " %s called for effect; deleted" fn) - ;; appending a nil here might not be necessary, but it can't hurt. - (byte-optimize-form - (cons 'progn (append (cdr form) '(nil))) t)) - - (t - ;; Otherwise, no args can be considered to be for-effect, - ;; even if the called function is for-effect, because we - ;; don't know anything about that function. - (cons fn (mapcar 'byte-optimize-form (cdr form))))))) - - -(defun byte-optimize-form (form &optional for-effect) - "The source-level pass of the optimizer." - ;; - ;; First, optimize all sub-forms of this one. - (setq form (byte-optimize-form-code-walker form for-effect)) - ;; - ;; after optimizing all subforms, optimize this form until it doesn't - ;; optimize any further. This means that some forms will be passed through - ;; the optimizer many times, but that's necessary to make the for-effect - ;; processing do as much as possible. - ;; - (let (opt new) - (if (and (consp form) - (symbolp (car form)) - (or (and for-effect - ;; we don't have any of these yet, but we might. - (setq opt (get (car form) 'byte-for-effect-optimizer))) - (setq opt (get (car form) 'byte-optimizer))) - (not (eq form (setq new (funcall opt form))))) - (progn -;; (if (equal form new) (error "bogus optimizer -- %s" opt)) - (byte-compile-log " %s\t==>\t%s" form new) - (setq new (byte-optimize-form new for-effect)) - new) - form))) - - -(defun byte-optimize-body (forms all-for-effect) - ;; optimize the cdr of a progn or implicit progn; all forms is a list of - ;; forms, all but the last of which are optimized with the assumption that - ;; they are being called for effect. the last is for-effect as well if - ;; all-for-effect is true. returns a new list of forms. - (let ((rest forms) - (result nil) - fe new) - (while rest - (setq fe (or all-for-effect (cdr rest))) - (setq new (and (car rest) (byte-optimize-form (car rest) fe))) - (if (or new (not fe)) - (setq result (cons new result))) - (setq rest (cdr rest))) - (nreverse result))) - - -;;; some source-level optimizers -;;; -;;; when writing optimizers, be VERY careful that the optimizer returns -;;; something not EQ to its argument if and ONLY if it has made a change. -;;; This implies that you cannot simply destructively modify the list; -;;; you must return something not EQ to it if you make an optimization. -;;; -;;; It is now safe to optimize code such that it introduces new bindings. - -;; I'd like this to be a defsubst, but let's not be self-referential... -(defmacro byte-compile-trueconstp (form) - ;; Returns non-nil if FORM is a non-nil constant. - (` (cond ((consp (, form)) (eq (car (, form)) 'quote)) - ((not (symbolp (, form)))) - ((eq (, form) t))))) - -;; If the function is being called with constant numeric args, -;; evaluate as much as possible at compile-time. This optimizer -;; assumes that the function is associative, like + or *. -(defun byte-optimize-associative-math (form) - (let ((args nil) - (constants nil) - (rest (cdr form))) - (while rest - (if (numberp (car rest)) - (setq constants (cons (car rest) constants)) - (setq args (cons (car rest) args))) - (setq rest (cdr rest))) - (if (cdr constants) - (if args - (list (car form) - (apply (car form) constants) - (if (cdr args) - (cons (car form) (nreverse args)) - (car args))) - (apply (car form) constants)) - form))) - -;; If the function is being called with constant numeric args, -;; evaluate as much as possible at compile-time. This optimizer -;; assumes that the function satisfies -;; (op x1 x2 ... xn) == (op ...(op (op x1 x2) x3) ...xn) -;; like - and /. -(defun byte-optimize-nonassociative-math (form) - (if (or (not (numberp (car (cdr form)))) - (not (numberp (car (cdr (cdr form)))))) - form - (let ((constant (car (cdr form))) - (rest (cdr (cdr form)))) - (while (numberp (car rest)) - (setq constant (funcall (car form) constant (car rest)) - rest (cdr rest))) - (if rest - (cons (car form) (cons constant rest)) - constant)))) - -;;(defun byte-optimize-associative-two-args-math (form) -;; (setq form (byte-optimize-associative-math form)) -;; (if (consp form) -;; (byte-optimize-two-args-left form) -;; form)) - -;;(defun byte-optimize-nonassociative-two-args-math (form) -;; (setq form (byte-optimize-nonassociative-math form)) -;; (if (consp form) -;; (byte-optimize-two-args-right form) -;; form)) - -(defun byte-optimize-approx-equal (x y) - (< (* (abs (- x y)) 100) (abs (+ x y)))) - -;; Collect all the constants from FORM, after the STARTth arg, -;; and apply FUN to them to make one argument at the end. -;; For functions that can handle floats, that optimization -;; can be incorrect because reordering can cause an overflow -;; that would otherwise be avoided by encountering an arg that is a float. -;; We avoid this problem by (1) not moving float constants and -;; (2) not moving anything if it would cause an overflow. -(defun byte-optimize-delay-constants-math (form start fun) - ;; Merge all FORM's constants from number START, call FUN on them - ;; and put the result at the end. - (let ((rest (nthcdr (1- start) form)) - (orig form) - ;; t means we must check for overflow. - (overflow (memq fun '(+ *)))) - (while (cdr (setq rest (cdr rest))) - (if (integerp (car rest)) - (let (constants) - (setq form (copy-sequence form) - rest (nthcdr (1- start) form)) - (while (setq rest (cdr rest)) - (cond ((integerp (car rest)) - (setq constants (cons (car rest) constants)) - (setcar rest nil)))) - ;; If necessary, check now for overflow - ;; that might be caused by reordering. - (if (and overflow - ;; We have overflow if the result of doing the arithmetic - ;; on floats is not even close to the result - ;; of doing it on integers. - (not (byte-optimize-approx-equal - (apply fun (mapcar 'float constants)) - (float (apply fun constants))))) - (setq form orig) - (setq form (nconc (delq nil form) - (list (apply fun (nreverse constants))))))))) - form)) - -(defun byte-optimize-plus (form) - (setq form (byte-optimize-delay-constants-math form 1 '+)) - (if (memq 0 form) (setq form (delq 0 (copy-sequence form)))) - ;;(setq form (byte-optimize-associative-two-args-math form)) - (cond ((null (cdr form)) - (condition-case () - (eval form) - (error form))) -;;; It is not safe to delete the function entirely -;;; (actually, it would be safe if we know the sole arg -;;; is not a marker). -;; ((null (cdr (cdr form))) (nth 1 form)) - (t form))) - -(defun byte-optimize-minus (form) - ;; Put constants at the end, except the last constant. - (setq form (byte-optimize-delay-constants-math form 2 '+)) - ;; Now only first and last element can be a number. - (let ((last (car (reverse (nthcdr 3 form))))) - (cond ((eq 0 last) - ;; (- x y ... 0) --> (- x y ...) - (setq form (copy-sequence form)) - (setcdr (cdr (cdr form)) (delq 0 (nthcdr 3 form)))) - ;; If form is (- CONST foo... CONST), merge first and last. - ((and (numberp (nth 1 form)) - (numberp last)) - (setq form (nconc (list '- (- (nth 1 form) last) (nth 2 form)) - (delq last (copy-sequence (nthcdr 3 form)))))))) -;;; It is not safe to delete the function entirely -;;; (actually, it would be safe if we know the sole arg -;;; is not a marker). -;;; (if (eq (nth 2 form) 0) -;;; (nth 1 form) ; (- x 0) --> x - (byte-optimize-predicate - (if (and (null (cdr (cdr (cdr form)))) - (eq (nth 1 form) 0)) ; (- 0 x) --> (- x) - (cons (car form) (cdr (cdr form))) - form)) -;;; ) - ) - -(defun byte-optimize-multiply (form) - (setq form (byte-optimize-delay-constants-math form 1 '*)) - ;; If there is a constant in FORM, it is now the last element. - (cond ((null (cdr form)) 1) -;;; It is not safe to delete the function entirely -;;; (actually, it would be safe if we know the sole arg -;;; is not a marker or if it appears in other arithmetic). -;;; ((null (cdr (cdr form))) (nth 1 form)) - ((let ((last (car (reverse form)))) - (cond ((eq 0 last) (cons 'progn (cdr form))) - ((eq 1 last) (delq 1 (copy-sequence form))) - ((eq -1 last) (list '- (delq -1 (copy-sequence form)))) - ((and (eq 2 last) - (memq t (mapcar 'symbolp (cdr form)))) - (prog1 (setq form (delq 2 (copy-sequence form))) - (while (not (symbolp (car (setq form (cdr form)))))) - (setcar form (list '+ (car form) (car form))))) - (form)))))) - -(defsubst byte-compile-butlast (form) - (nreverse (cdr (reverse form)))) - -(defun byte-optimize-divide (form) - (setq form (byte-optimize-delay-constants-math form 2 '*)) - (let ((last (car (reverse (cdr (cdr form)))))) - (if (numberp last) - (cond ((= (length form) 3) - (if (and (numberp (nth 1 form)) - (not (zerop last)) - (condition-case nil - (/ (nth 1 form) last) - (error nil))) - (setq form (list 'progn (/ (nth 1 form) last))))) - ((= last 1) - (setq form (byte-compile-butlast form))) - ((numberp (nth 1 form)) - (setq form (cons (car form) - (cons (/ (nth 1 form) last) - (byte-compile-butlast (cdr (cdr form))))) - last nil)))) - (cond -;;; ((null (cdr (cdr form))) -;;; (nth 1 form)) - ((eq (nth 1 form) 0) - (append '(progn) (cdr (cdr form)) '(0))) - ((eq last -1) - (list '- (if (nthcdr 3 form) - (byte-compile-butlast form) - (nth 1 form)))) - (form)))) - -(defun byte-optimize-logmumble (form) - (setq form (byte-optimize-delay-constants-math form 1 (car form))) - (byte-optimize-predicate - (cond ((memq 0 form) - (setq form (if (eq (car form) 'logand) - (cons 'progn (cdr form)) - (delq 0 (copy-sequence form))))) - ((and (eq (car-safe form) 'logior) - (memq -1 form)) - (cons 'progn (cdr form))) - (form)))) - - -(defun byte-optimize-binary-predicate (form) - (if (byte-compile-constp (nth 1 form)) - (if (byte-compile-constp (nth 2 form)) - (condition-case () - (list 'quote (eval form)) - (error form)) - ;; This can enable some lapcode optimizations. - (list (car form) (nth 2 form) (nth 1 form))) - form)) - -(defun byte-optimize-predicate (form) - (let ((ok t) - (rest (cdr form))) - (while (and rest ok) - (setq ok (byte-compile-constp (car rest)) - rest (cdr rest))) - (if ok - (condition-case () - (list 'quote (eval form)) - (error form)) - form))) - -(defun byte-optimize-identity (form) - (if (and (cdr form) (null (cdr (cdr form)))) - (nth 1 form) - (byte-compile-warn "identity called with %d arg%s, but requires 1" - (length (cdr form)) - (if (= 1 (length (cdr form))) "" "s")) - form)) - -(put 'identity 'byte-optimizer 'byte-optimize-identity) - -(put '+ 'byte-optimizer 'byte-optimize-plus) -(put '* 'byte-optimizer 'byte-optimize-multiply) -(put '- 'byte-optimizer 'byte-optimize-minus) -(put '/ 'byte-optimizer 'byte-optimize-divide) -(put 'max 'byte-optimizer 'byte-optimize-associative-math) -(put 'min 'byte-optimizer 'byte-optimize-associative-math) - -(put '= 'byte-optimizer 'byte-optimize-binary-predicate) -(put 'eq 'byte-optimizer 'byte-optimize-binary-predicate) -(put 'eql 'byte-optimizer 'byte-optimize-binary-predicate) -(put 'equal 'byte-optimizer 'byte-optimize-binary-predicate) -(put 'string= 'byte-optimizer 'byte-optimize-binary-predicate) -(put 'string-equal 'byte-optimizer 'byte-optimize-binary-predicate) - -(put '< 'byte-optimizer 'byte-optimize-predicate) -(put '> 'byte-optimizer 'byte-optimize-predicate) -(put '<= 'byte-optimizer 'byte-optimize-predicate) -(put '>= 'byte-optimizer 'byte-optimize-predicate) -(put '1+ 'byte-optimizer 'byte-optimize-predicate) -(put '1- 'byte-optimizer 'byte-optimize-predicate) -(put 'not 'byte-optimizer 'byte-optimize-predicate) -(put 'null 'byte-optimizer 'byte-optimize-predicate) -(put 'memq 'byte-optimizer 'byte-optimize-predicate) -(put 'consp 'byte-optimizer 'byte-optimize-predicate) -(put 'listp 'byte-optimizer 'byte-optimize-predicate) -(put 'symbolp 'byte-optimizer 'byte-optimize-predicate) -(put 'stringp 'byte-optimizer 'byte-optimize-predicate) -(put 'string< 'byte-optimizer 'byte-optimize-predicate) -(put 'string-lessp 'byte-optimizer 'byte-optimize-predicate) - -(put 'logand 'byte-optimizer 'byte-optimize-logmumble) -(put 'logior 'byte-optimizer 'byte-optimize-logmumble) -(put 'logxor 'byte-optimizer 'byte-optimize-logmumble) -(put 'lognot 'byte-optimizer 'byte-optimize-predicate) - -(put 'car 'byte-optimizer 'byte-optimize-predicate) -(put 'cdr 'byte-optimizer 'byte-optimize-predicate) -(put 'car-safe 'byte-optimizer 'byte-optimize-predicate) -(put 'cdr-safe 'byte-optimizer 'byte-optimize-predicate) - - -;; I'm not convinced that this is necessary. Doesn't the optimizer loop -;; take care of this? - Jamie -;; I think this may some times be necessary to reduce ie (quote 5) to 5, -;; so arithmetic optimizers recognize the numeric constant. - Hallvard -(put 'quote 'byte-optimizer 'byte-optimize-quote) -(defun byte-optimize-quote (form) - (if (or (consp (nth 1 form)) - (and (symbolp (nth 1 form)) - (not (memq (nth 1 form) '(nil t))))) - form - (nth 1 form))) - -(defun byte-optimize-zerop (form) - (cond ((numberp (nth 1 form)) - (eval form)) - (byte-compile-delete-errors - (list '= (nth 1 form) 0)) - (form))) - -(put 'zerop 'byte-optimizer 'byte-optimize-zerop) - -(defun byte-optimize-and (form) - ;; Simplify if less than 2 args. - ;; if there is a literal nil in the args to `and', throw it and following - ;; forms away, and surround the `and' with (progn ... nil). - (cond ((null (cdr form))) - ((memq nil form) - (list 'progn - (byte-optimize-and - (prog1 (setq form (copy-sequence form)) - (while (nth 1 form) - (setq form (cdr form))) - (setcdr form nil))) - nil)) - ((null (cdr (cdr form))) - (nth 1 form)) - ((byte-optimize-predicate form)))) - -(defun byte-optimize-or (form) - ;; Throw away nil's, and simplify if less than 2 args. - ;; If there is a literal non-nil constant in the args to `or', throw away all - ;; following forms. - (if (memq nil form) - (setq form (delq nil (copy-sequence form)))) - (let ((rest form)) - (while (cdr (setq rest (cdr rest))) - (if (byte-compile-trueconstp (car rest)) - (setq form (copy-sequence form) - rest (setcdr (memq (car rest) form) nil)))) - (if (cdr (cdr form)) - (byte-optimize-predicate form) - (nth 1 form)))) - -(defun byte-optimize-cond (form) - ;; if any clauses have a literal nil as their test, throw them away. - ;; if any clause has a literal non-nil constant as its test, throw - ;; away all following clauses. - (let (rest) - ;; This must be first, to reduce (cond (t ...) (nil)) to (progn t ...) - (while (setq rest (assq nil (cdr form))) - (setq form (delq rest (copy-sequence form)))) - (if (memq nil (cdr form)) - (setq form (delq nil (copy-sequence form)))) - (setq rest form) - (while (setq rest (cdr rest)) - (cond ((byte-compile-trueconstp (car-safe (car rest))) - (cond ((eq rest (cdr form)) - (setq form - (if (cdr (car rest)) - (if (cdr (cdr (car rest))) - (cons 'progn (cdr (car rest))) - (nth 1 (car rest))) - (car (car rest))))) - ((cdr rest) - (setq form (copy-sequence form)) - (setcdr (memq (car rest) form) nil))) - (setq rest nil))))) - ;; - ;; Turn (cond (( <x> )) ... ) into (or <x> (cond ... )) - (if (eq 'cond (car-safe form)) - (let ((clauses (cdr form))) - (if (and (consp (car clauses)) - (null (cdr (car clauses)))) - (list 'or (car (car clauses)) - (byte-optimize-cond - (cons (car form) (cdr (cdr form))))) - form)) - form)) - -(defun byte-optimize-if (form) - ;; (if <true-constant> <then> <else...>) ==> <then> - ;; (if <false-constant> <then> <else...>) ==> (progn <else...>) - ;; (if <test> nil <else...>) ==> (if (not <test>) (progn <else...>)) - ;; (if <test> <then> nil) ==> (if <test> <then>) - (let ((clause (nth 1 form))) - (cond ((byte-compile-trueconstp clause) - (nth 2 form)) - ((null clause) - (if (nthcdr 4 form) - (cons 'progn (nthcdr 3 form)) - (nth 3 form))) - ((nth 2 form) - (if (equal '(nil) (nthcdr 3 form)) - (list 'if clause (nth 2 form)) - form)) - ((or (nth 3 form) (nthcdr 4 form)) - (list 'if - ;; Don't make a double negative; - ;; instead, take away the one that is there. - (if (and (consp clause) (memq (car clause) '(not null)) - (= (length clause) 2)) ; (not xxxx) or (not (xxxx)) - (nth 1 clause) - (list 'not clause)) - (if (nthcdr 4 form) - (cons 'progn (nthcdr 3 form)) - (nth 3 form)))) - (t - (list 'progn clause nil))))) - -(defun byte-optimize-while (form) - (if (nth 1 form) - form)) - -(put 'and 'byte-optimizer 'byte-optimize-and) -(put 'or 'byte-optimizer 'byte-optimize-or) -(put 'cond 'byte-optimizer 'byte-optimize-cond) -(put 'if 'byte-optimizer 'byte-optimize-if) -(put 'while 'byte-optimizer 'byte-optimize-while) - -;; byte-compile-negation-optimizer lives in bytecomp.el -(put '/= 'byte-optimizer 'byte-compile-negation-optimizer) -(put 'atom 'byte-optimizer 'byte-compile-negation-optimizer) -(put 'nlistp 'byte-optimizer 'byte-compile-negation-optimizer) - - -(defun byte-optimize-funcall (form) - ;; (funcall '(lambda ...) ...) ==> ((lambda ...) ...) - ;; (funcall 'foo ...) ==> (foo ...) - (let ((fn (nth 1 form))) - (if (memq (car-safe fn) '(quote function)) - (cons (nth 1 fn) (cdr (cdr form))) - form))) - -(defun byte-optimize-apply (form) - ;; If the last arg is a literal constant, turn this into a funcall. - ;; The funcall optimizer can then transform (funcall 'foo ...) -> (foo ...). - (let ((fn (nth 1 form)) - (last (nth (1- (length form)) form))) ; I think this really is fastest - (or (if (or (null last) - (eq (car-safe last) 'quote)) - (if (listp (nth 1 last)) - (let ((butlast (nreverse (cdr (reverse (cdr (cdr form))))))) - (nconc (list 'funcall fn) butlast - (mapcar '(lambda (x) (list 'quote x)) (nth 1 last)))) - (byte-compile-warn - "last arg to apply can't be a literal atom: %s" - (prin1-to-string last)) - nil)) - form))) - -(put 'funcall 'byte-optimizer 'byte-optimize-funcall) -(put 'apply 'byte-optimizer 'byte-optimize-apply) - - -(put 'let 'byte-optimizer 'byte-optimize-letX) -(put 'let* 'byte-optimizer 'byte-optimize-letX) -(defun byte-optimize-letX (form) - (cond ((null (nth 1 form)) - ;; No bindings - (cons 'progn (cdr (cdr form)))) - ((or (nth 2 form) (nthcdr 3 form)) - form) - ;; The body is nil - ((eq (car form) 'let) - (append '(progn) (mapcar 'car-safe (mapcar 'cdr-safe (nth 1 form))) - '(nil))) - (t - (let ((binds (reverse (nth 1 form)))) - (list 'let* (reverse (cdr binds)) (nth 1 (car binds)) nil))))) - - -(put 'nth 'byte-optimizer 'byte-optimize-nth) -(defun byte-optimize-nth (form) - (if (and (= (safe-length form) 3) (memq (nth 1 form) '(0 1))) - (list 'car (if (zerop (nth 1 form)) - (nth 2 form) - (list 'cdr (nth 2 form)))) - (byte-optimize-predicate form))) - -(put 'nthcdr 'byte-optimizer 'byte-optimize-nthcdr) -(defun byte-optimize-nthcdr (form) - (if (and (= (safe-length form) 3) (not (memq (nth 1 form) '(0 1 2)))) - (byte-optimize-predicate form) - (let ((count (nth 1 form))) - (setq form (nth 2 form)) - (while (>= (setq count (1- count)) 0) - (setq form (list 'cdr form))) - form))) - -;;; enumerating those functions which need not be called if the returned -;;; value is not used. That is, something like -;;; (progn (list (something-with-side-effects) (yow)) -;;; (foo)) -;;; may safely be turned into -;;; (progn (progn (something-with-side-effects) (yow)) -;;; (foo)) -;;; Further optimizations will turn (progn (list 1 2 3) 'foo) into 'foo. - -;;; I wonder if I missed any :-\) -(let ((side-effect-free-fns - '(% * + - / /= 1+ 1- < <= = > >= abs acos append aref ash asin atan - assoc assq - boundp buffer-file-name buffer-local-variables buffer-modified-p - buffer-substring - capitalize car-less-than-car car cdr ceiling concat coordinates-in-window-p - copy-marker cos count-lines - default-boundp default-value documentation downcase - elt exp expt fboundp featurep - file-directory-p file-exists-p file-locked-p file-name-absolute-p - file-newer-than-file-p file-readable-p file-symlink-p file-writable-p - float floor format - get get-buffer get-buffer-window getenv get-file-buffer - int-to-string - length log log10 logand logb logior lognot logxor lsh - marker-buffer max member memq min mod - next-window nth nthcdr number-to-string - parse-colon-path previous-window - radians-to-degrees rassq regexp-quote reverse round - sin sqrt string< string= string-equal string-lessp string-to-char - string-to-int string-to-number substring symbol-plist - tan upcase user-variable-p vconcat - window-buffer window-dedicated-p window-edges window-height - window-hscroll window-minibuffer-p window-width - zerop)) - (side-effect-and-error-free-fns - '(arrayp atom - bobp bolp buffer-end buffer-list buffer-size buffer-string bufferp - car-safe case-table-p cdr-safe char-or-string-p commandp cons consp - current-buffer - dot dot-marker eobp eolp eq eql equal eventp floatp framep - get-largest-window get-lru-window - identity ignore integerp integer-or-marker-p interactive-p - invocation-directory invocation-name - keymapp list listp - make-marker mark mark-marker markerp memory-limit minibuffer-window - mouse-movement-p - natnump nlistp not null number-or-marker-p numberp - one-window-p overlayp - point point-marker point-min point-max processp - selected-window sequencep stringp subrp symbolp syntax-table-p - user-full-name user-login-name user-original-login-name - user-real-login-name user-real-uid user-uid - vector vectorp - window-configuration-p window-live-p windowp))) - (while side-effect-free-fns - (put (car side-effect-free-fns) 'side-effect-free t) - (setq side-effect-free-fns (cdr side-effect-free-fns))) - (while side-effect-and-error-free-fns - (put (car side-effect-and-error-free-fns) 'side-effect-free 'error-free) - (setq side-effect-and-error-free-fns (cdr side-effect-and-error-free-fns))) - nil) - - -(defun byte-compile-splice-in-already-compiled-code (form) - ;; form is (byte-code "..." [...] n) - (if (not (memq byte-optimize '(t lap))) - (byte-compile-normal-call form) - (byte-inline-lapcode - (byte-decompile-bytecode-1 (nth 1 form) (nth 2 form) t)) - (setq byte-compile-maxdepth (max (+ byte-compile-depth (nth 3 form)) - byte-compile-maxdepth)) - (setq byte-compile-depth (1+ byte-compile-depth)))) - -(put 'byte-code 'byte-compile 'byte-compile-splice-in-already-compiled-code) - - -(defconst byte-constref-ops - '(byte-constant byte-constant2 byte-varref byte-varset byte-varbind)) - -;;; This function extracts the bitfields from variable-length opcodes. -;;; Originally defined in disass.el (which no longer uses it.) - -(defun disassemble-offset () - "Don't call this!" - ;; fetch and return the offset for the current opcode. - ;; return NIL if this opcode has no offset - ;; OP, PTR and BYTES are used and set dynamically - (defvar op) - (defvar ptr) - (defvar bytes) - (cond ((< op byte-nth) - (let ((tem (logand op 7))) - (setq op (logand op 248)) - (cond ((eq tem 6) - (setq ptr (1+ ptr)) ;offset in next byte - (aref bytes ptr)) - ((eq tem 7) - (setq ptr (1+ ptr)) ;offset in next 2 bytes - (+ (aref bytes ptr) - (progn (setq ptr (1+ ptr)) - (lsh (aref bytes ptr) 8)))) - (t tem)))) ;offset was in opcode - ((>= op byte-constant) - (prog1 (- op byte-constant) ;offset in opcode - (setq op byte-constant))) - ((and (>= op byte-constant2) - (<= op byte-goto-if-not-nil-else-pop)) - (setq ptr (1+ ptr)) ;offset in next 2 bytes - (+ (aref bytes ptr) - (progn (setq ptr (1+ ptr)) - (lsh (aref bytes ptr) 8)))) - ((and (>= op byte-listN) - (<= op byte-insertN)) - (setq ptr (1+ ptr)) ;offset in next byte - (aref bytes ptr)))) - - -;;; This de-compiler is used for inline expansion of compiled functions, -;;; and by the disassembler. -;;; -;;; This list contains numbers, which are pc values, -;;; before each instruction. -(defun byte-decompile-bytecode (bytes constvec) - "Turns BYTECODE into lapcode, referring to CONSTVEC." - (let ((byte-compile-constants nil) - (byte-compile-variables nil) - (byte-compile-tag-number 0)) - (byte-decompile-bytecode-1 bytes constvec))) - -;; As byte-decompile-bytecode, but updates -;; byte-compile-{constants, variables, tag-number}. -;; If MAKE-SPLICEABLE is true, then `return' opcodes are replaced -;; with `goto's destined for the end of the code. -;; That is for use by the compiler. -;; If MAKE-SPLICEABLE is nil, we are being called for the disassembler. -;; In that case, we put a pc value into the list -;; before each insn (or its label). -(defun byte-decompile-bytecode-1 (bytes constvec &optional make-spliceable) - (let ((length (length bytes)) - (ptr 0) optr tag tags op offset - lap tmp - endtag - (retcount 0)) - (while (not (= ptr length)) - (or make-spliceable - (setq lap (cons ptr lap))) - (setq op (aref bytes ptr) - optr ptr - offset (disassemble-offset)) ; this does dynamic-scope magic - (setq op (aref byte-code-vector op)) - (cond ((memq op byte-goto-ops) - ;; it's a pc - (setq offset - (cdr (or (assq offset tags) - (car (setq tags - (cons (cons offset - (byte-compile-make-tag)) - tags))))))) - ((cond ((eq op 'byte-constant2) (setq op 'byte-constant) t) - ((memq op byte-constref-ops))) - (setq tmp (aref constvec offset) - offset (if (eq op 'byte-constant) - (byte-compile-get-constant tmp) - (or (assq tmp byte-compile-variables) - (car (setq byte-compile-variables - (cons (list tmp) - byte-compile-variables))))))) - ((and make-spliceable - (eq op 'byte-return)) - (if (= ptr (1- length)) - (setq op nil) - (setq offset (or endtag (setq endtag (byte-compile-make-tag))) - op 'byte-goto)))) - ;; lap = ( [ (pc . (op . arg)) ]* ) - (setq lap (cons (cons optr (cons op (or offset 0))) - lap)) - (setq ptr (1+ ptr))) - ;; take off the dummy nil op that we replaced a trailing "return" with. - (let ((rest lap)) - (while rest - (cond ((numberp (car rest))) - ((setq tmp (assq (car (car rest)) tags)) - ;; this addr is jumped to - (setcdr rest (cons (cons nil (cdr tmp)) - (cdr rest))) - (setq tags (delq tmp tags)) - (setq rest (cdr rest)))) - (setq rest (cdr rest)))) - (if tags (error "optimizer error: missed tags %s" tags)) - (if (null (car (cdr (car lap)))) - (setq lap (cdr lap))) - (if endtag - (setq lap (cons (cons nil endtag) lap))) - ;; remove addrs, lap = ( [ (op . arg) | (TAG tagno) ]* ) - (mapcar (function (lambda (elt) - (if (numberp elt) - elt - (cdr elt)))) - (nreverse lap)))) - - -;;; peephole optimizer - -(defconst byte-tagref-ops (cons 'TAG byte-goto-ops)) - -(defconst byte-conditional-ops - '(byte-goto-if-nil byte-goto-if-not-nil byte-goto-if-nil-else-pop - byte-goto-if-not-nil-else-pop)) - -(defconst byte-after-unbind-ops - '(byte-constant byte-dup - byte-symbolp byte-consp byte-stringp byte-listp byte-numberp byte-integerp - byte-eq byte-equal byte-not - byte-cons byte-list1 byte-list2 ; byte-list3 byte-list4 - byte-interactive-p) - ;; How about other side-effect-free-ops? Is it safe to move an - ;; error invocation (such as from nth) out of an unwind-protect? - "Byte-codes that can be moved past an unbind.") - -(defconst byte-compile-side-effect-and-error-free-ops - '(byte-constant byte-dup byte-symbolp byte-consp byte-stringp byte-listp - byte-integerp byte-numberp byte-eq byte-equal byte-not byte-car-safe - byte-cdr-safe byte-cons byte-list1 byte-list2 byte-point byte-point-max - byte-point-min byte-following-char byte-preceding-char - byte-current-column byte-eolp byte-eobp byte-bolp byte-bobp - byte-current-buffer byte-interactive-p)) - -(defconst byte-compile-side-effect-free-ops - (nconc - '(byte-varref byte-nth byte-memq byte-car byte-cdr byte-length byte-aref - byte-symbol-value byte-get byte-concat2 byte-concat3 byte-sub1 byte-add1 - byte-eqlsign byte-gtr byte-lss byte-leq byte-geq byte-diff byte-negate - byte-plus byte-max byte-min byte-mult byte-char-after byte-char-syntax - byte-buffer-substring byte-string= byte-string< byte-nthcdr byte-elt - byte-member byte-assq byte-quo byte-rem) - byte-compile-side-effect-and-error-free-ops)) - -;;; This crock is because of the way DEFVAR_BOOL variables work. -;;; Consider the code -;;; -;;; (defun foo (flag) -;;; (let ((old-pop-ups pop-up-windows) -;;; (pop-up-windows flag)) -;;; (cond ((not (eq pop-up-windows old-pop-ups)) -;;; (setq old-pop-ups pop-up-windows) -;;; ...)))) -;;; -;;; Uncompiled, old-pop-ups will always be set to nil or t, even if FLAG is -;;; something else. But if we optimize -;;; -;;; varref flag -;;; varbind pop-up-windows -;;; varref pop-up-windows -;;; not -;;; to -;;; varref flag -;;; dup -;;; varbind pop-up-windows -;;; not -;;; -;;; we break the program, because it will appear that pop-up-windows and -;;; old-pop-ups are not EQ when really they are. So we have to know what -;;; the BOOL variables are, and not perform this optimization on them. -;;; -(defconst byte-boolean-vars - '(abbrev-all-caps abbrevs-changed byte-metering-on - cannot-suspend completion-auto-help completion-ignore-case - cursor-in-echo-area debug-on-next-call debug-on-quit - delete-exited-processes enable-recursive-minibuffers - highlight-nonselected-windows indent-tabs-mode inhibit-local-menu-bar-menus - insert-default-directory inverse-video load-force-doc-strings - load-in-progress menu-prompting minibuffer-auto-raise - mode-line-inverse-video multiple-frames no-redraw-on-reenter noninteractive - parse-sexp-ignore-comments pop-up-frames pop-up-windows - print-escape-newlines system-uses-terminfo truncate-partial-width-windows - visible-bell vms-stmlf-recfm words-include-escapes) - "DEFVAR_BOOL variables. Giving these any non-nil value sets them to t. -If this does not enumerate all DEFVAR_BOOL variables, the byte-optimizer -may generate incorrect code.") - -(defun byte-optimize-lapcode (lap &optional for-effect) - "Simple peephole optimizer. LAP is both modified and returned." - (let (lap0 off0 - lap1 off1 - lap2 off2 - (keep-going 'first-time) - (add-depth 0) - rest tmp tmp2 tmp3 - (side-effect-free (if byte-compile-delete-errors - byte-compile-side-effect-free-ops - byte-compile-side-effect-and-error-free-ops))) - (while keep-going - (or (eq keep-going 'first-time) - (byte-compile-log-lap " ---- next pass")) - (setq rest lap - keep-going nil) - (while rest - (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. - (cond ;; - ;; <side-effect-free> pop --> <deleted> - ;; ...including: - ;; const-X pop --> <deleted> - ;; varref-X pop --> <deleted> - ;; dup pop --> <deleted> - ;; - ((and (eq 'byte-discard (car lap1)) - (memq (car lap0) side-effect-free)) - (setq keep-going t) - (setq tmp (aref byte-stack+-info (symbol-value (car lap0)))) - (setq rest (cdr rest)) - (cond ((= tmp 1) - (byte-compile-log-lap - " %s discard\t-->\t<deleted>" lap0) - (setq lap (delq lap0 (delq lap1 lap)))) - ((= tmp 0) - (byte-compile-log-lap - " %s discard\t-->\t<deleted> discard" lap0) - (setq lap (delq lap0 lap))) - ((= tmp -1) - (byte-compile-log-lap - " %s discard\t-->\tdiscard discard" lap0) - (setcar lap0 'byte-discard) - (setcdr lap0 0)) - ((error "Optimizer error: too much on the stack")))) - ;; - ;; goto*-X X: --> X: - ;; - ((and (memq (car lap0) byte-goto-ops) - (eq (cdr lap0) lap1)) - (cond ((eq (car lap0) 'byte-goto) - (setq lap (delq lap0 lap)) - (setq tmp "<deleted>")) - ((memq (car lap0) byte-goto-always-pop-ops) - (setcar lap0 (setq tmp 'byte-discard)) - (setcdr lap0 0)) - ((error "Depth conflict at tag %d" (nth 2 lap0)))) - (and (memq byte-optimize-log '(t byte)) - (byte-compile-log " (goto %s) %s:\t-->\t%s %s:" - (nth 1 lap1) (nth 1 lap1) - tmp (nth 1 lap1))) - (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. - ;; - ((and (eq 'byte-varref (car lap2)) - (eq (cdr lap1) (cdr lap2)) - (memq (car lap1) '(byte-varset byte-varbind))) - (if (and (setq tmp (memq (car (cdr lap2)) byte-boolean-vars)) - (not (eq (car lap0) 'byte-constant))) - nil - (setq keep-going t) - (if (memq (car lap0) '(byte-constant byte-dup)) - (progn - (setq tmp (if (or (not tmp) - (memq (car (cdr lap0)) '(nil t))) - (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 - ;; (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-compile-log-lap " dup %s discard\t-->\t%s" lap1 lap1) - (setq keep-going t - rest (cdr rest)) - (setq lap (delq lap0 (delq lap2 lap)))) - ;; - ;; 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)) - (or (eq 'byte-goto-if-nil (car lap1)) - (eq 'byte-goto-if-not-nil (car lap1)))) - (byte-compile-log-lap " not %s\t-->\t%s" - lap1 - (cons - (if (eq (car lap1) 'byte-goto-if-nil) - 'byte-goto-if-not-nil - 'byte-goto-if-nil) - (cdr lap1))) - (setcar lap1 (if (eq (car lap1) 'byte-goto-if-nil) - 'byte-goto-if-not-nil - 'byte-goto-if-nil)) - (setq lap (delq lap0 lap)) - (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 (or (eq 'byte-goto-if-nil (car lap0)) - (eq 'byte-goto-if-not-nil (car lap0))) ; 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) - (setq lap (delq lap0 lap)) - (setcar lap1 inverse) - (setq keep-going t))) - ;; - ;; const goto-if-* --> whatever - ;; - ((and (eq 'byte-constant (car lap0)) - (memq (car lap1) byte-conditional-ops)) - (cond ((if (or (eq (car lap1) 'byte-goto-if-nil) - (eq (car lap1) 'byte-goto-if-nil-else-pop)) - (car (cdr lap0)) - (not (car (cdr lap0)))) - (byte-compile-log-lap " %s %s\t-->\t<deleted>" - lap0 lap1) - (setq rest (cdr rest) - lap (delq lap0 (delq lap1 lap)))) - (t - (if (memq (car lap1) byte-goto-always-pop-ops) - (progn - (byte-compile-log-lap " %s %s\t-->\t%s" - lap0 lap1 (cons 'byte-goto (cdr lap1))) - (setq lap (delq lap0 lap))) - (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 - (cons 'byte-goto (cdr lap1)))) - (setcar lap1 'byte-goto))) - (setq keep-going t)) - ;; - ;; varref-X varref-X --> varref-X dup - ;; varref-X [dup ...] varref-X --> varref-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 (eq 'byte-varref (car lap0)) - (progn - (setq tmp (cdr rest)) - (while (eq (car (car tmp)) 'byte-dup) - (setq tmp (cdr tmp))) - t) - (eq (cdr lap0) (cdr (car tmp))) - (eq 'byte-varref (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) - (setq rest tmp)) - ;; - ;; TAG1: TAG2: --> TAG1: <deleted> - ;; (and other references to TAG2 are replaced with TAG1) - ;; - ((and (eq (car lap0) 'TAG) - (eq (car lap1) 'TAG)) - (and (memq byte-optimize-log '(t byte)) - (byte-compile-log " adjacent tags %d and %d merged" - (nth 1 lap1) (nth 1 lap0))) - (setq tmp3 lap) - (while (setq tmp2 (rassq lap0 tmp3)) - (setcdr tmp2 lap1) - (setq tmp3 (cdr (memq tmp2 tmp3)))) - (setq lap (delq lap0 lap) - keep-going t)) - ;; - ;; unused-TAG: --> <deleted> - ;; - ((and (eq 'TAG (car lap0)) - (not (rassq lap0 lap))) - (and (memq byte-optimize-log '(t byte)) - (byte-compile-log " unused tag %d removed" (nth 1 lap0))) - (setq lap (delq lap0 lap) - 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 lap))) - 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)))) - (rplacd rest tmp)) - (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) - ;; - ((and (eq 'byte-unbind (car lap1)) - (memq (car lap0) '(byte-varbind byte-save-excursion - byte-save-restriction)) - (< 0 (cdr lap1))) - (if (zerop (setcdr lap1 (1- (cdr lap1)))) - (delq lap1 rest)) - (if (eq (car lap0) 'byte-varbind) - (setcar rest (cons 'byte-discard 0)) - (setq lap (delq lap0 lap))) - (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) lap)))) - '(byte-goto byte-return))) - (cond ((and (not (eq tmp lap0)) - (or (eq (car lap0) 'byte-goto) - (eq (car tmp) 'byte-goto))) - (byte-compile-log-lap " %s [%s]\t-->\t%s" - (car lap0) tmp tmp) - (if (eq (car tmp) 'byte-return) - (setcar lap0 'byte-return)) - (setcdr lap0 (cdr tmp)) - (setq keep-going t)))) - ;; - ;; 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 (car (car (setq tmp (cdr (memq (cdr lap0) lap))))) - (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 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 (car (car (setq tmp (cdr (memq (cdr lap1) lap))))) - (eval-when-compile - (cons 'byte-discard byte-conditional-ops))) - (not (eq lap1 (car tmp)))) - (setq tmp2 (car tmp)) - (cond ((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 rest (cons nil rest))) - (t - ;; 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))) - (setq lap (delq lap0 lap)))) - (setq keep-going 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). - ;; - ((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) lap))))) - '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 - (cdr (car (setq tmp (cdr (memq (cdr lap0) lap)))))) - (memq (car (car tmp)) - '(byte-goto byte-goto-if-nil byte-goto-if-not-nil - byte-goto-if-nil-else-pop))) -;; (byte-compile-log-lap " %s %s, %s %s --> moved conditional" -;; lap0 lap1 (cdr lap0) (car tmp)) - (let ((newtag (byte-compile-make-tag))) - (byte-compile-log-lap - "%s %s: ... %s: %s\t-->\t%s ... %s:" - lap0 (nth 1 lap1) (nth 1 (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) - - (nth 1 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)) - ) - (setq rest (cdr rest))) - ) - ;; Cleanup stage: - ;; Rebuild byte-compile-constants / byte-compile-variables. - ;; Simple optimizations that would inhibit other optimizations if they - ;; were done in the optimizing loop, and optimizations which there is no - ;; need to do more than once. - (setq byte-compile-constants nil - byte-compile-variables nil) - (setq rest lap) - (while rest - (setq lap0 (car rest) - lap1 (nth 1 rest)) - (if (memq (car lap0) byte-constref-ops) - (if (eq (cdr lap0) 'byte-constant) - (or (memq (cdr lap0) byte-compile-variables) - (setq byte-compile-variables (cons (cdr lap0) - byte-compile-variables))) - (or (memq (cdr lap0) byte-compile-constants) - (setq byte-compile-constants (cons (cdr lap0) - byte-compile-constants))))) - (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) (car (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))) - ;; - ;; 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)))) - (setq keep-going t) - (setq lap (delq lap0 lap)) - (setcdr lap1 (+ (cdr lap1) (cdr lap0)))) - ) - (setq rest (cdr rest))) - (setq byte-compile-maxdepth (+ byte-compile-maxdepth add-depth))) - lap) - -(provide 'byte-optimize) - - -;; To avoid "lisp nesting exceeds max-lisp-eval-depth" when this file compiles -;; itself, compile some of its most used recursive functions (at load time). -;; -(eval-when-compile - (or (byte-code-function-p (symbol-function 'byte-optimize-form)) - (assq 'byte-code (symbol-function 'byte-optimize-form)) - (let ((byte-optimize nil) - (byte-compile-warnings nil)) - (mapcar '(lambda (x) - (or noninteractive (message "compiling %s..." x)) - (byte-compile x) - (or noninteractive (message "compiling %s...done" x))) - '(byte-optimize-form - byte-optimize-body - byte-optimize-predicate - byte-optimize-binary-predicate - ;; Inserted some more than necessary, to speed it up. - byte-optimize-form-code-walker - byte-optimize-lapcode)))) - nil) - -;;; byte-opt.el ends here |