diff options
Diffstat (limited to 'lisp/emacs-lisp/byte-opt.el')
| -rw-r--r-- | lisp/emacs-lisp/byte-opt.el | 2242 |
1 files changed, 1225 insertions, 1017 deletions
diff --git a/lisp/emacs-lisp/byte-opt.el b/lisp/emacs-lisp/byte-opt.el index 492218fcd7c..142f206428e 100644 --- a/lisp/emacs-lisp/byte-opt.el +++ b/lisp/emacs-lisp/byte-opt.el @@ -225,9 +225,17 @@ (byte-compile-log-lap-1 ,format-string ,@args))) +(defvar byte-optimize--lexvars nil + "Lexical variables in scope, in reverse order of declaration. +Each element is on the form (NAME KEEP [VALUE]), where: + NAME is the variable name, + KEEP is a boolean indicating whether the binding must be retained, + VALUE, if present, is a substitutable expression. +Earlier variables shadow later ones with the same name.") + ;;; byte-compile optimizers to support inlining -(put 'inline 'byte-optimizer 'byte-optimize-inline-handler) +(put 'inline 'byte-optimizer #'byte-optimize-inline-handler) (defun byte-optimize-inline-handler (form) "byte-optimize-handler for the `inline' special-form." @@ -266,106 +274,108 @@ ((pred byte-code-function-p) ;; (message "Inlining byte-code for %S!" name) ;; The byte-code will be really inlined in byte-compile-unfold-bcf. + (byte-compile--check-arity-bytecode form fn) `(,fn ,@(cdr form))) ((or `(lambda . ,_) `(closure . ,_)) - (if (not (or (eq fn localfn) ;From the same file => same mode. - (eq (car fn) ;Same mode. - (if lexical-binding 'closure 'lambda)))) - ;; While byte-compile-unfold-bcf can inline dynbind byte-code into - ;; letbind byte-code (or any other combination for that matter), we - ;; can only inline dynbind source into dynbind source or letbind - ;; source into letbind source. - (progn - ;; We can of course byte-compile the inlined function - ;; first, and then inline its byte-code. - (byte-compile name) - `(,(symbol-function name) ,@(cdr form))) - (let ((newfn (if (eq fn localfn) - ;; If `fn' is from the same file, it has already - ;; been preprocessed! - `(function ,fn) - (byte-compile-preprocess - (byte-compile--reify-function fn))))) - (if (eq (car-safe newfn) 'function) - (byte-compile-unfold-lambda `(,(cadr newfn) ,@(cdr form))) - ;; This can happen because of macroexp-warn-and-return &co. - (byte-compile-warn - "Inlining closure %S failed" name) - form)))) + ;; While byte-compile-unfold-bcf can inline dynbind byte-code into + ;; letbind byte-code (or any other combination for that matter), we + ;; can only inline dynbind source into dynbind source or letbind + ;; source into letbind source. + ;; When the function comes from another file, we byte-compile + ;; the inlined function first, and then inline its byte-code. + ;; This also has the advantage that the final code does not + ;; depend on the order of compilation of ELisp files, making + ;; the build more reproducible. + (if (eq fn localfn) + ;; From the same file => same mode. + (macroexp--unfold-lambda `(,fn ,@(cdr form))) + ;; Since we are called from inside the optimiser, we need to make + ;; sure not to propagate lexvar values. + (let ((byte-optimize--lexvars nil) + ;; Silence all compilation warnings: the useful ones should + ;; be displayed when the function's source file will be + ;; compiled anyway, but more importantly we would otherwise + ;; emit spurious warnings here because we don't have the full + ;; context, such as `declare-functions' placed earlier in the + ;; source file's code or `with-suppressed-warnings' that + ;; surrounded the `defsubst'. + (byte-compile-warnings nil)) + (byte-compile name)) + (let ((bc (symbol-function name))) + (byte-compile--check-arity-bytecode form bc) + `(,bc ,@(cdr form))))) (_ ;; Give up on inlining. form)))) - -;; ((lambda ...) ...) -(defun byte-compile-unfold-lambda (form &optional name) - ;; In lexical-binding mode, let and functions don't bind vars in the same way - ;; (let obey special-variable-p, but functions don't). But luckily, this - ;; doesn't matter here, because function's behavior is underspecified so it - ;; can safely be turned into a `let', even though the reverse is not true. - (or name (setq name "anonymous lambda")) - (let* ((lambda (car form)) - (values (cdr form)) - (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))) - ;; FIXME: The checks below do not belong in an optimization phase. - (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) - - ;; The following leads to infinite recursion when loading a - ;; file containing `(defsubst f () (f))', and then trying to - ;; byte-compile that file. - ;(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 +(defvar byte-optimize--vars-outside-condition nil + "Alist of variables lexically bound outside conditionally executed code. +Variables here are sensitive to mutation inside the conditional code, +since their contents in sequentially later code depends on the path taken +and may no longer be statically known. +Same format as `byte-optimize--lexvars', with shared structure and contents.") + +(defvar byte-optimize--vars-outside-loop nil + "Alist of variables lexically bound outside the innermost `while' loop. +Variables here are sensitive to mutation inside the loop, since this can +occur an indeterminate number of times and thus have effect on code +sequentially preceding the mutation itself. +Same format as `byte-optimize--lexvars', with shared structure and contents.") + +(defvar byte-optimize--dynamic-vars nil + "List of variables declared as dynamic during optimisation.") + +(defun byte-optimize--substitutable-p (expr) + "Whether EXPR is a constant that can be propagated." + ;; Only consider numbers, symbols and strings to be values for substitution + ;; purposes. Numbers and symbols are immutable, and mutating string + ;; literals (or results from constant-evaluated string-returning functions) + ;; can be considered undefined. + ;; (What about other quoted values, like conses?) + (or (booleanp expr) + (numberp expr) + (stringp expr) + (and (consp expr) + (memq (car expr) '(quote function)) + (symbolp (cadr expr))) + (keywordp expr))) + +(defmacro byte-optimize--pcase (exp &rest cases) + ;; When we do + ;; + ;; (pcase EXP + ;; (`(if ,exp ,then ,else) (DO-TEST)) + ;; (`(plus ,e2 ,e2) (DO-ADD)) + ;; (`(times ,e2 ,e2) (DO-MULT)) + ;; ...) + ;; + ;; we usually don't want to fall back to the default case if + ;; the value of EXP is of a form like `(if E1 E2)' or `(plus E1)' + ;; or `(times E1 E2 E3)', instead we either want to signal an error + ;; that EXP has an unexpected shape, or we want to carry on as if + ;; it had the right shape (ignore the extra data and pretend the missing + ;; data is nil) because it should simply never happen. + ;; + ;; The macro below implements the second option by rewriting patterns + ;; like `(if ,exp ,then ,else)' + ;; to `(if . (or `(,exp ,then ,else) pcase--dontcare))'. + ;; + ;; The resulting macroexpansion is also significantly cleaner/smaller/faster. + (declare (indent 1) (debug pcase)) + `(pcase ,exp + . ,(mapcar (lambda (case) + `(,(pcase (car case) + ((and `(,'\` (,_ . (,'\, ,_))) pat) pat) + (`(,'\` (,head . ,tail)) + (list '\` + (cons head + (list '\, `(or ,(list '\` tail) pcase--dontcare))))) + (pat pat)) + . ,(cdr case))) + cases))) + (defun byte-optimize-form-code-walker (form for-effect) ;; ;; For normal function calls, We can just mapcar the optimizer the cdr. But @@ -374,228 +384,349 @@ ;; 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)) - ((eq (car-safe fn) 'lambda) - (let ((newform (byte-compile-unfold-lambda form))) - (if (eq newform form) - ;; Some error occurred, avoid infinite recursion - form - (byte-optimize-form-code-walker newform for-effect)))) - ((eq (car-safe fn) 'closure) 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)) - (macroexp-progn (byte-optimize-body (cdr form) for-effect)) - (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))) - - ((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) - (when (< (length form) 3) - (byte-compile-warn "too few arguments for `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 (mapcar 'byte-optimize-form - backwards))))) - (cons fn (mapcar 'byte-optimize-form (cdr form))))) - - ((eq fn 'interactive) - (byte-compile-warn "misplaced interactive spec: `%s'" - (prin1-to-string form)) - nil) - - ((eq fn 'function) - ;; This forms is compiled as constant or by breaking out - ;; all the subexpressions and compiling them separately. - form) - - ((eq fn 'condition-case) - (if byte-compile--use-old-handlers - ;; Will be optimized later. - form - `(condition-case ,(nth 1 form) ;Not evaluated. - ,(byte-optimize-form (nth 2 form) for-effect) - ,@(mapcar (lambda (clause) - `(,(car clause) - ,@(byte-optimize-body (cdr clause) for-effect))) - (nthcdr 3 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) - (cons fn - (cons (byte-optimize-form (nth 1 form) nil) - (if byte-compile--use-old-handlers - ;; The body of a catch is compiled (and thus - ;; optimized) as a top-level form, so don't do it - ;; here. - (cdr (cdr form)) - (byte-optimize-body (cdr form) for-effect))))) - - ((eq fn 'ignore) - ;; Don't treat the args to `ignore' as being - ;; computed for effect. We want to avoid the warnings - ;; that might occur if they were treated that way. - ;; However, don't actually bother calling `ignore'. - `(prog1 nil . ,(mapcar 'byte-optimize-form (cdr form)))) - - ;; Needed as long as we run byte-optimize-form after cconv. - ((eq fn 'internal-make-closure) form) - - ((byte-code-function-p fn) - (cons fn (mapcar #'byte-optimize-form (cdr form)))) - - ((not (symbolp fn)) - (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 "value returned from %s is unused" - (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)) + ;; FIXME: There are a bunch of `byte-compile-warn' here which arguably + ;; have no place in an optimizer: the corresponding tests should be + ;; performed in `macroexpand-all', or in `cconv', or in `bytecomp'. + (let ((fn (car-safe form))) + (byte-optimize--pcase form + ((pred (not consp)) + (cond + ((and for-effect + (or byte-compile-delete-errors + (not (symbolp form)) + (eq form t) + (keywordp form))) + nil) + ((symbolp form) + (let ((lexvar (assq form byte-optimize--lexvars))) + (cond + ((not lexvar) form) + (for-effect nil) + ((cddr lexvar) ; Value available? + (if (assq form byte-optimize--vars-outside-loop) + ;; Cannot substitute; mark for retention to avoid the + ;; variable being eliminated. + (progn + (setcar (cdr lexvar) t) + form) + ;; variable value to use + (caddr lexvar))) + (t form)))) + (t form))) + (`(quote . ,v) + (if (or (not v) (cdr v)) + (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 (car v) + (not for-effect) + form)) + (`(,(or 'let 'let*) . ,rest) + (cons fn (byte-optimize-let-form fn rest for-effect))) + (`(cond . ,clauses) + ;; The condition in the first clause is always executed, but + ;; right now we treat all of them as conditional for simplicity. + (let ((byte-optimize--vars-outside-condition byte-optimize--lexvars)) + (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)) + clauses)))) + (`(progn . ,exps) + ;; As an extra added bonus, this simplifies (progn <x>) --> <x>. + (if (cdr exps) + (macroexp-progn (byte-optimize-body exps for-effect)) + (byte-optimize-form (car exps) for-effect))) + (`(prog1 ,exp . ,exps) + (let ((exp-opt (byte-optimize-form exp for-effect))) + (if exps + (let ((exps-opt (byte-optimize-body exps t))) + (if (macroexp-const-p exp-opt) + `(progn ,@exps-opt ,exp-opt) + `(prog1 ,exp-opt ,@exps-opt))) + exp-opt))) + + (`(,(or `save-excursion `save-restriction `save-current-buffer) . ,exps) + ;; 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 exps for-effect))) + + (`(if ,test ,then . ,else) + ;; FIXME: We are conservative here: any variable changed in the + ;; THEN branch will be barred from substitution in the ELSE + ;; branch, despite the branches being mutually exclusive. + + ;; The test is always executed. + (let* ((test-opt (byte-optimize-form test nil)) + (const (macroexp-const-p test-opt)) + ;; The branches are traversed unconditionally when possible. + (byte-optimize--vars-outside-condition + (if const + byte-optimize--vars-outside-condition + byte-optimize--lexvars)) + ;; Avoid traversing dead branches. + (then-opt (and test-opt (byte-optimize-form then for-effect))) + (else-opt (and (not (and test-opt const)) + (byte-optimize-body else for-effect)))) + `(if ,test-opt ,then-opt . ,else-opt))) + + (`(,(or 'and 'or) . ,exps) ; Remember, and/or are control structures. + ;; FIXME: We have to traverse the expressions in left-to-right + ;; order (because that is the order of evaluation and variable + ;; mutations must be found prior to their use), but doing so we miss + ;; some optimisation opportunities: + ;; consider (and A B) in a for-effect context, where B => nil. + ;; Then A could be optimised in a for-effect context too. + (let ((tail exps) + (args nil)) + (when tail + ;; The first argument is always unconditional. + (push (byte-optimize-form + (car tail) (and for-effect (null (cdr tail)))) + args) + (setq tail (cdr tail)) + ;; Remaining arguments are conditional. + (let ((byte-optimize--vars-outside-condition byte-optimize--lexvars)) + (while tail + (push (byte-optimize-form + (car tail) (and for-effect (null (cdr tail)))) + args) + (setq tail (cdr tail))))) + (cons fn (nreverse args)))) + + (`(while ,exp . ,exps) + ;; FIXME: We conservatively prevent the substitution of any variable + ;; bound outside the loop in case it is mutated later in the loop, + ;; but this misses many opportunities: variables not mutated in the + ;; loop at all, and variables affecting the initial condition (which + ;; is always executed unconditionally). + (let* ((byte-optimize--vars-outside-condition byte-optimize--lexvars) + (byte-optimize--vars-outside-loop byte-optimize--lexvars) + (condition (byte-optimize-form exp nil)) + (body (byte-optimize-body exps t))) + `(while ,condition . ,body))) + + + (`(interactive . ,_) + (byte-compile-warn "misplaced interactive spec: `%s'" + (prin1-to-string form)) + nil) + + (`(function . ,_) + ;; This forms is compiled as constant or by breaking out + ;; all the subexpressions and compiling them separately. + form) - (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. - (let ((args (mapcar #'byte-optimize-form (cdr form)))) - (if (and (get fn 'pure) - (byte-optimize-all-constp args)) - (list 'quote (apply fn (mapcar #'eval args))) - (cons fn args))))))) - -(defun byte-optimize-all-constp (list) - "Non-nil if all elements of LIST satisfy `macroexp-const-p'." - (let ((constant t)) - (while (and list constant) - (unless (macroexp-const-p (car list)) - (setq constant nil)) - (setq list (cdr list))) - constant)) + (`(condition-case ,var ,exp . ,clauses) + (let ((byte-optimize--vars-outside-condition byte-optimize--lexvars)) + `(condition-case ,var ;Not evaluated. + ,(byte-optimize-form exp for-effect) + ,@(mapcar (lambda (clause) + (let ((byte-optimize--lexvars + (and lexical-binding + (if var + (cons (list var t) + byte-optimize--lexvars) + byte-optimize--lexvars)))) + (cons (car clause) + (byte-optimize-body (cdr clause) for-effect)))) + clauses)))) + + (`(unwind-protect ,exp . ,exps) + ;; The unwinding part of an unwind-protect is compiled (and thus + ;; optimized) as a top-level form, but run the optimizer for it here + ;; anyway for lexical variable usage and substitution. But the + ;; protected part has the same for-effect status as the + ;; unwind-protect itself. (The unwinding part is always for effect, + ;; but that isn't handled properly yet.) + (let* ((byte-optimize--vars-outside-condition byte-optimize--lexvars) + (bodyform (byte-optimize-form exp for-effect))) + (pcase exps + (`(:fun-body ,f) + `(unwind-protect ,bodyform + :fun-body ,(byte-optimize-form f nil))) + (_ + `(unwind-protect ,bodyform + . ,(byte-optimize-body exps t)))))) + + (`(catch ,tag . ,exps) + (let ((byte-optimize--vars-outside-condition byte-optimize--lexvars)) + `(catch ,(byte-optimize-form tag nil) + . ,(byte-optimize-body exps for-effect)))) + + (`(ignore . ,exps) + ;; Don't treat the args to `ignore' as being + ;; computed for effect. We want to avoid the warnings + ;; that might occur if they were treated that way. + ;; However, don't actually bother calling `ignore'. + `(progn ,@(mapcar #'byte-optimize-form exps) nil)) + + ;; Needed as long as we run byte-optimize-form after cconv. + (`(internal-make-closure . ,_) + ;; Look up free vars and mark them to be kept, so that they + ;; won't be optimised away. + (dolist (var (caddr form)) + (let ((lexvar (assq var byte-optimize--lexvars))) + (when lexvar + (setcar (cdr lexvar) t)))) + form) -(defun byte-optimize-form (form &optional for-effect) + (`((lambda . ,_) . ,_) + (let ((newform (macroexp--unfold-lambda form))) + (if (eq newform form) + ;; Some error occurred, avoid infinite recursion. + form + (byte-optimize-form newform for-effect)))) + + ;; FIXME: Strictly speaking, I think this is a bug: (closure...) + ;; is a *value* and shouldn't appear in the car. + (`((closure . ,_) . ,_) form) + + (`(setq . ,args) + (let ((var-expr-list nil)) + (while args + (unless (and (consp args) + (symbolp (car args)) (consp (cdr args))) + (byte-compile-warn "malformed setq form: %S" form)) + (let* ((var (car args)) + (expr (cadr args)) + (lexvar (assq var byte-optimize--lexvars)) + (value (byte-optimize-form expr nil))) + (when lexvar + ;; Set a new value or inhibit further substitution. + (setcdr (cdr lexvar) + (and + ;; Inhibit if bound outside conditional code. + (not (assq var byte-optimize--vars-outside-condition)) + ;; The new value must be substitutable. + (byte-optimize--substitutable-p value) + (list value))) + (setcar (cdr lexvar) t)) ; Mark variable to be kept. + (push var var-expr-list) + (push value var-expr-list)) + (setq args (cddr args))) + (cons fn (nreverse var-expr-list)))) + + (`(defvar ,(and (pred symbolp) name) . ,rest) + (let ((optimized-rest (and rest + (cons (byte-optimize-form (car rest) nil) + (cdr rest))))) + (push name byte-optimize--dynamic-vars) + `(defvar ,name . ,optimized-rest))) + + (`(,(pred byte-code-function-p) . ,exps) + (cons fn (mapcar #'byte-optimize-form exps))) + + (`(,(pred (not symbolp)) . ,_) + (byte-compile-warn "`%s' is a malformed function" + (prin1-to-string fn)) + form) + + ((guard (when for-effect + (if-let ((tmp (get fn 'side-effect-free))) + (or byte-compile-delete-errors + (eq tmp 'error-free) + (progn + (byte-compile-warn "value returned from %s is unused" + (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)) + + (_ + ;; 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. + (let ((form (cons fn (mapcar #'byte-optimize-form (cdr form))))) + (if (get fn 'pure) + (byte-optimize-constant-args form) + form)))))) + +(defun byte-optimize-one-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 (function-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))) + ;; Make optimiser aware of lexical arguments. + (let ((byte-optimize--lexvars + (mapcar (lambda (v) (list (car v) t)) + byte-compile--lexical-environment))) + (byte-optimize-form form for-effect))) + +(defun byte-optimize-form (form &optional for-effect) + (while + (progn + ;; First, optimize all sub-forms of this one. + (setq form (byte-optimize-form-code-walker form for-effect)) + + ;; If a form-specific optimiser is available, run it and start over + ;; until a fixpoint has been reached. + (and (consp form) + (symbolp (car form)) + (let ((opt (function-get (car form) 'byte-optimizer))) + (and opt + (let ((old form) + (new (funcall opt form))) + (byte-compile-log " %s\t==>\t%s" old new) + (setq form new) + (not (eq new old)))))))) + form) + +(defun byte-optimize-let-form (head form for-effect) + ;; 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. + (if lexical-binding + (let* ((byte-optimize--lexvars byte-optimize--lexvars) + (new-lexvars nil) + (let-vars nil)) + (dolist (binding (car form)) + (let* ((name (car binding)) + (expr (byte-optimize-form (cadr binding) nil)) + (value (and (byte-optimize--substitutable-p expr) + (list expr))) + (lexical (not (or (special-variable-p name) + (memq name byte-compile-bound-variables) + (memq name byte-optimize--dynamic-vars)))) + (lexinfo (and lexical (cons name (cons nil value))))) + (push (cons name (cons expr (cdr lexinfo))) let-vars) + (when lexinfo + (push lexinfo (if (eq head 'let*) + byte-optimize--lexvars + new-lexvars))))) + (setq byte-optimize--lexvars + (append new-lexvars byte-optimize--lexvars)) + ;; Walk the body expressions, which may mutate some of the records, + ;; and generate new bindings that exclude unused variables. + (let* ((byte-optimize--dynamic-vars byte-optimize--dynamic-vars) + (opt-body (byte-optimize-body (cdr form) for-effect)) + (bindings nil)) + (dolist (var let-vars) + ;; VAR is (NAME EXPR [KEEP [VALUE]]) + (when (or (not (nthcdr 3 var)) (nth 2 var)) + ;; Value not present, or variable marked to be kept. + (push (list (nth 0 var) (nth 1 var)) bindings))) + (cons bindings opt-body))) + + ;; With dynamic binding, no substitutions are in effect. + (let ((byte-optimize--lexvars nil)) + (cons + (mapcar (lambda (binding) + (if (symbolp binding) + binding + (when (or (atom binding) (cddr binding)) + (byte-compile-warn "malformed let binding: `%S'" binding)) + (list (car binding) + (byte-optimize-form (nth 1 binding) nil)))) + (car form)) + (byte-optimize-body (cdr form) for-effect))))) (defun byte-optimize-body (forms all-for-effect) @@ -664,45 +795,36 @@ (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))) + (let ((const (apply (car form) (nreverse constants)))) + (if args + (append (list (car form) const) + (nreverse args)) + const)) + form))) -;; Portable Emacs integers fall in this range. -(defconst byte-opt--portable-max #x1fffffff) -(defconst byte-opt--portable-min (- -1 byte-opt--portable-max)) - -;; True if N is a number that works the same on all Emacs platforms. -;; Portable Emacs fixnums are exactly representable as floats on all -;; Emacs platforms, and (except for -0.0) any floating-point number -;; that equals one of these integers must be the same on all -;; platforms. Although other floating-point numbers such as 0.5 are -;; also portable, it can be tricky to characterize them portably so -;; they are not optimized. -(defun byte-opt--portable-numberp (n) - (and (numberp n) - (<= byte-opt--portable-min n byte-opt--portable-max) - (= n (floor n)) - (not (and (floatp n) (zerop n) - (condition-case () (< (/ n) 0) (error)))))) - -;; Use OP to reduce any leading prefix of portable numbers in the list -;; (cons ACCUM ARGS) down to a single portable number, and return the +(defun byte-optimize-min-max (form) + "Optimize `min' and `max'." + (let ((opt (byte-optimize-associative-math form))) + (if (and (consp opt) (memq (car opt) '(min max)) + (= (length opt) 4)) + ;; (OP x y z) -> (OP (OP x y) z), in order to use binary byte ops. + (list (car opt) + (list (car opt) (nth 1 opt) (nth 2 opt)) + (nth 3 opt)) + opt))) + +;; Use OP to reduce any leading prefix of constant numbers in the list +;; (cons ACCUM ARGS) down to a single number, and return the ;; resulting list A of arguments. The idea is that applying OP to A ;; is equivalent to (but likely more efficient than) applying OP to ;; (cons ACCUM ARGS), on any Emacs platform. Do not make any special ;; provision for (- X) or (/ X); for example, it is the caller’s ;; responsibility that (- 1 0) should not be "optimized" to (- 1). (defun byte-opt--arith-reduce (op accum args) - (when (byte-opt--portable-numberp accum) + (when (numberp accum) (let (accum1) - (while (and (byte-opt--portable-numberp (car args)) - (byte-opt--portable-numberp + (while (and (numberp (car args)) + (numberp (setq accum1 (condition-case () (funcall op accum (car args)) (error)))) @@ -725,6 +847,9 @@ (integer (if integer-is-first arg1 arg2)) (other (if integer-is-first arg2 arg1))) (list (if (eq integer 1) '1+ '1-) other))) + ;; (+ x y z) -> (+ (+ x y) z) + ((= (length args) 3) + `(+ ,(byte-optimize-plus `(+ ,(car args) ,(cadr args))) ,@(cddr args))) ;; not further optimized ((equal args (cdr form)) form) (t (cons '+ args))))) @@ -747,35 +872,19 @@ ;; (- x -1) --> (1+ x) ((equal (cdr args) '(-1)) (list '1+ (car args))) - ;; (- n) -> -n, where n and -n are portable numbers. + ;; (- n) -> -n, where n and -n are constant numbers. ;; This must be done separately since byte-opt--arith-reduce ;; is not applied to (- n). ((and (null (cdr args)) - (byte-opt--portable-numberp (car args)) - (byte-opt--portable-numberp (- (car args)))) + (numberp (car args))) (- (car args))) + ;; (- x y z) -> (- (- x y) z) + ((= (length args) 3) + `(- ,(byte-optimize-minus `(- ,(car args) ,(cadr args))) ,@(cddr args))) ;; not further optimized ((equal args (cdr form)) form) (t (cons '- args)))))) -(defun byte-optimize-1+ (form) - (let ((args (cdr form))) - (when (null (cdr args)) - (let ((n (car args))) - (when (and (byte-opt--portable-numberp n) - (byte-opt--portable-numberp (1+ n))) - (setq form (1+ n)))))) - form) - -(defun byte-optimize-1- (form) - (let ((args (cdr form))) - (when (null (cdr args)) - (let ((n (car args))) - (when (and (byte-opt--portable-numberp n) - (byte-opt--portable-numberp (1- n))) - (setq form (1- n)))))) - form) - (defun byte-optimize-multiply (form) (let* ((args (remq 1 (byte-opt--arith-reduce #'* 1 (cdr form))))) (cond @@ -783,6 +892,10 @@ ((null args) 1) ;; (* n) -> n, where n is a number ((and (null (cdr args)) (numberp (car args))) (car args)) + ;; (* x y z) -> (* (* x y) z) + ((= (length args) 3) + `(* ,(byte-optimize-multiply `(* ,(car args) ,(cadr args))) + ,@(cddr args))) ;; not further optimized ((equal args (cdr form)) form) (t (cons '* args))))) @@ -811,10 +924,10 @@ (condition-case () (list 'quote (eval form)) (error form))) - (t ;; This can enable some lapcode optimizations. + (t ;; Moving the constant to the end can enable some lapcode optimizations. (list (car form) (nth 2 form) (nth 1 form))))) -(defun byte-optimize-predicate (form) +(defun byte-optimize-constant-args (form) (let ((ok t) (rest (cdr form))) (while (and rest ok) @@ -829,56 +942,80 @@ (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)) (defun byte-optimize--constant-symbol-p (expr) "Whether EXPR is a constant symbol." (and (macroexp-const-p expr) (symbolp (eval expr)))) +(defun byte-optimize--fixnump (o) + "Return whether O is guaranteed to be a fixnum in all Emacsen. +See Info node `(elisp) Integer Basics'." + (and (fixnump o) (<= -536870912 o 536870911))) + (defun byte-optimize-equal (form) - ;; Replace `equal' or `eql' with `eq' if at least one arg is a symbol. + ;; Replace `equal' or `eql' with `eq' if at least one arg is a + ;; symbol or fixnum. (byte-optimize-binary-predicate (if (= (length (cdr form)) 2) (if (or (byte-optimize--constant-symbol-p (nth 1 form)) - (byte-optimize--constant-symbol-p (nth 2 form))) + (byte-optimize--constant-symbol-p (nth 2 form)) + (byte-optimize--fixnump (nth 1 form)) + (byte-optimize--fixnump (nth 2 form))) (cons 'eq (cdr form)) form) ;; Arity errors reported elsewhere. form))) +(defun byte-optimize-eq (form) + (pcase (cdr form) + ((or `(,x nil) `(nil ,x)) `(not ,x)) + (_ (byte-optimize-binary-predicate form)))) + (defun byte-optimize-member (form) ;; Replace `member' or `memql' with `memq' if the first arg is a symbol, - ;; or the second arg is a list of symbols. + ;; or the second arg is a list of symbols. Same with fixnums. (if (= (length (cdr form)) 2) (if (or (byte-optimize--constant-symbol-p (nth 1 form)) + (byte-optimize--fixnump (nth 1 form)) (let ((arg2 (nth 2 form))) (and (macroexp-const-p arg2) (let ((listval (eval arg2))) (and (listp listval) - (not (memq nil (mapcar #'symbolp listval)))))))) + (not (memq nil (mapcar + (lambda (o) + (or (symbolp o) + (byte-optimize--fixnump o))) + listval)))))))) (cons 'memq (cdr form)) form) ;; Arity errors reported elsewhere. form)) +(defun byte-optimize-assoc (form) + ;; Replace 2-argument `assoc' with `assq', `rassoc' with `rassq', + ;; if the first arg is a symbol or fixnum. + (cond + ((/= (length form) 3) + form) + ((or (byte-optimize--constant-symbol-p (nth 1 form)) + (byte-optimize--fixnump (nth 1 form))) + (cons (if (eq (car form) 'assoc) 'assq 'rassq) + (cdr form))) + (t (byte-optimize-constant-args form)))) + (defun byte-optimize-memq (form) ;; (memq foo '(bar)) => (and (eq foo 'bar) '(bar)) - (if (/= (length (cdr form)) 2) - (byte-compile-warn "memq called with %d arg%s, but requires 2" - (length (cdr form)) - (if (= 1 (length (cdr form))) "" "s")) - (let ((list (nth 2 form))) - (when (and (eq (car-safe list) 'quote) + (if (= (length (cdr form)) 2) + (let ((list (nth 2 form))) + (if (and (eq (car-safe list) 'quote) (listp (setq list (cadr list))) (= (length list) 1)) - (setq form (byte-optimize-and - `(and ,(byte-optimize-predicate - `(eq ,(nth 1 form) ',(nth 0 list))) - ',list))))) - (byte-optimize-predicate form))) + `(and (eq ,(nth 1 form) ',(nth 0 list)) + ',list) + form)) + ;; Arity errors reported elsewhere. + form)) (defun byte-optimize-concat (form) "Merge adjacent constant arguments to `concat'." @@ -907,62 +1044,38 @@ form ; No improvement. (cons 'concat (nreverse newargs))))) -(put 'identity 'byte-optimizer 'byte-optimize-identity) -(put 'memq 'byte-optimizer 'byte-optimize-memq) -(put 'memql 'byte-optimizer 'byte-optimize-member) -(put 'member 'byte-optimizer 'byte-optimize-member) - -(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-equal) -(put 'equal 'byte-optimizer 'byte-optimize-equal) -(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-1+) -(put '1- 'byte-optimizer 'byte-optimize-1-) -(put 'not 'byte-optimizer 'byte-optimize-predicate) -(put 'null '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 'proper-list-p 'byte-optimizer 'byte-optimize-predicate) - -(put 'logand 'byte-optimizer 'byte-optimize-predicate) -(put 'logior 'byte-optimizer 'byte-optimize-predicate) -(put 'logxor 'byte-optimizer 'byte-optimize-predicate) -(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) - -(put 'concat 'byte-optimizer 'byte-optimize-concat) +(put 'identity 'byte-optimizer #'byte-optimize-identity) +(put 'memq 'byte-optimizer #'byte-optimize-memq) +(put 'memql 'byte-optimizer #'byte-optimize-member) +(put 'member 'byte-optimizer #'byte-optimize-member) +(put 'assoc 'byte-optimizer #'byte-optimize-assoc) +(put 'rassoc 'byte-optimizer #'byte-optimize-assoc) + +(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-min-max) +(put 'min 'byte-optimizer #'byte-optimize-min-max) + +(put '= 'byte-optimizer #'byte-optimize-binary-predicate) +(put 'eq 'byte-optimizer #'byte-optimize-eq) +(put 'eql 'byte-optimizer #'byte-optimize-equal) +(put 'equal 'byte-optimizer #'byte-optimize-equal) +(put 'string= 'byte-optimizer #'byte-optimize-binary-predicate) +(put 'string-equal 'byte-optimizer #'byte-optimize-binary-predicate) + +(put 'concat 'byte-optimizer #'byte-optimize-concat) ;; 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) +(put 'quote 'byte-optimizer #'byte-optimize-quote) (defun byte-optimize-quote (form) (if (or (consp (nth 1 form)) (and (symbolp (nth 1 form)) - (not (macroexp--const-symbol-p form)))) + (not (macroexp--const-symbol-p (nth 1 form))))) form (nth 1 form))) @@ -981,7 +1094,7 @@ nil)) ((null (cdr (cdr form))) (nth 1 form)) - ((byte-optimize-predicate form)))) + ((byte-optimize-constant-args form)))) (defun byte-optimize-or (form) ;; Throw away nil's, and simplify if less than 2 args. @@ -994,7 +1107,7 @@ (setq form (copy-sequence form) rest (setcdr (memq (car rest) form) nil)))) (if (cdr (cdr form)) - (byte-optimize-predicate form) + (byte-optimize-constant-args form) (nth 1 form)))) (defun byte-optimize-cond (form) @@ -1076,16 +1189,16 @@ (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) +(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) +(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) @@ -1099,52 +1212,68 @@ (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) + (if (= (length form) 2) + ;; single-argument `apply' is not worth optimizing (bug#40968) + form + (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) + (pcase form + ;; No bindings. + (`(,_ () . ,body) + `(progn . ,body)) + + ;; Body is empty or just contains a constant. + (`(,head ,bindings . ,(or '() `(,(and const (pred macroexp-const-p))))) + (if (eq head 'let) + `(progn ,@(mapcar (lambda (binding) + (and (consp binding) (cadr binding))) + bindings) + ,const) + `(let* ,(butlast bindings) ,(cadar (last bindings)) ,const))) + + ;; Body is last variable. + (`(,head ,bindings ,(and var (pred symbolp) (pred (not keywordp)) + (pred (not booleanp)) + (guard (eq var (caar (last bindings)))))) + (if (eq head 'let) + `(progn ,@(mapcar (lambda (binding) + (and (consp binding) (cadr binding))) + bindings)) + `(let* ,(butlast bindings) ,(cadar (last bindings))))) + + (_ form))) + + +(put 'nth 'byte-optimizer #'byte-optimize-nth) (defun byte-optimize-nth (form) (if (= (safe-length form) 3) (if (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)) + form) form)) -(put 'nthcdr 'byte-optimizer 'byte-optimize-nthcdr) +(put 'nthcdr 'byte-optimizer #'byte-optimize-nthcdr) (defun byte-optimize-nthcdr (form) (if (= (safe-length form) 3) (if (memq (nth 1 form) '(0 1 2)) @@ -1153,14 +1282,22 @@ (while (>= (setq count (1- count)) 0) (setq form (list 'cdr form))) form) - (byte-optimize-predicate form)) + form) + form)) + +(put 'cons 'byte-optimizer #'byte-optimize-cons) +(defun byte-optimize-cons (form) + ;; (cons X nil) => (list X) + (if (and (= (safe-length form) 3) + (null (nth 2 form))) + `(list ,(nth 1 form)) form)) ;; Fixme: delete-char -> delete-region (byte-coded) ;; optimize string-as-unibyte, string-as-multibyte, string-make-unibyte, ;; string-make-multibyte for constant args. -(put 'set 'byte-optimizer 'byte-optimize-set) +(put 'set 'byte-optimizer #'byte-optimize-set) (defun byte-optimize-set (form) (let ((var (car-safe (cdr-safe form)))) (cond @@ -1196,13 +1333,15 @@ ;; I wonder if I missed any :-\) (let ((side-effect-free-fns '(% * + - / /= 1+ 1- < <= = > >= abs acos append aref ash asin atan - assoc assq + assq + bool-vector-count-consecutive bool-vector-count-population + bool-vector-subsetp boundp buffer-file-name buffer-local-variables buffer-modified-p buffer-substring byte-code-function-p capitalize car-less-than-car car cdr ceiling char-after char-before char-equal char-to-string char-width compare-strings compare-window-configurations concat coordinates-in-window-p - copy-alist copy-sequence copy-marker cos count-lines + copy-alist copy-sequence copy-marker copysign cos count-lines current-time-string current-time-zone decode-char decode-time default-boundp default-value documentation downcase @@ -1215,21 +1354,26 @@ frame-visible-p fround ftruncate get gethash get-buffer get-buffer-window getenv get-file-buffer hash-table-count - int-to-string intern-soft + int-to-string intern-soft isnan keymap-parent - length line-beginning-position line-end-position + lax-plist-get ldexp + length length< length> length= + line-beginning-position line-end-position local-variable-if-set-p local-variable-p locale-info log log10 logand logb logcount logior lognot logxor lsh - make-list make-string make-symbol marker-buffer max member memq min - minibuffer-selected-window minibuffer-window + make-byte-code make-list make-string make-symbol mark marker-buffer max + member memq memql min minibuffer-selected-window minibuffer-window mod multibyte-char-to-unibyte next-window nth nthcdr number-to-string parse-colon-path plist-get plist-member prefix-numeric-value previous-window prin1-to-string propertize degrees-to-radians - radians-to-degrees rassq rassoc read-from-string regexp-quote - region-beginning region-end reverse round - sin sqrt string string< string= string-equal string-lessp string-to-char - string-to-number substring + radians-to-degrees rassq rassoc read-from-string regexp-opt + regexp-quote region-beginning region-end reverse round + sin sqrt string string< string= string-equal string-lessp + string> string-greaterp string-empty-p + string-prefix-p string-suffix-p string-blank-p + string-search string-to-char + string-to-number string-to-syntax substring sxhash sxhash-equal sxhash-eq sxhash-eql symbol-function symbol-name symbol-plist symbol-value string-make-unibyte string-make-multibyte string-as-multibyte string-as-unibyte @@ -1252,7 +1396,7 @@ window-total-height window-total-width window-use-time window-vscroll window-width zerop)) (side-effect-and-error-free-fns - '(arrayp atom + '(always arrayp atom bignump bobp bolp bool-vector-p buffer-end buffer-list buffer-size buffer-string bufferp car-safe case-table-p cdr-safe char-or-string-p characterp @@ -1267,7 +1411,7 @@ invocation-directory invocation-name keymapp keywordp list listp - make-marker mark mark-marker markerp max-char + make-marker mark-marker markerp max-char memory-limit mouse-movement-p natnump nlistp not null number-or-marker-p numberp @@ -1279,7 +1423,7 @@ standard-case-table standard-syntax-table stringp subrp symbolp syntax-table syntax-table-p this-command-keys this-command-keys-vector this-single-command-keys - this-single-command-raw-keys + this-single-command-raw-keys type-of user-real-login-name user-real-uid user-uid vector vectorp visible-frame-list wholenump window-configuration-p window-live-p @@ -1296,9 +1440,9 @@ ;; Pure functions are side-effect free functions whose values depend ;; only on their arguments, not on the platform. For these functions, ;; calls with constant arguments can be evaluated at compile time. -;; This may shift runtime errors to compile time. For example, logand -;; is pure since its results are machine-independent, whereas ash is -;; not pure because (ash 1 29)'s value depends on machine word size. +;; For example, ash is pure since its results are machine-independent, +;; whereas lsh is not pure because (lsh -1 -1)'s value depends on the +;; fixnum range. ;; ;; When deciding whether a function is pure, do not worry about ;; mutable strings or markers, as they are so unlikely in real code @@ -1308,9 +1452,43 @@ ;; values if a marker is moved. (let ((pure-fns - '(% concat logand logcount logior lognot logxor - regexp-opt regexp-quote - string-to-char string-to-syntax symbol-name))) + '(concat regexp-opt regexp-quote + string-to-char string-to-syntax symbol-name + eq eql + = /= < <= >= > min max + + - * / % mod abs ash 1+ 1- sqrt + logand logior lognot logxor logcount + copysign isnan ldexp float logb + floor ceiling round truncate + ffloor fceiling fround ftruncate + string= string-equal string< string-lessp string> string-greaterp + string-empty-p string-blank-p string-prefix-p string-suffix-p + string-search + consp atom listp nlistp proper-list-p + sequencep arrayp vectorp stringp bool-vector-p hash-table-p + null not + numberp integerp floatp natnump characterp + integer-or-marker-p number-or-marker-p char-or-string-p + symbolp keywordp + type-of + identity ignore + + ;; The following functions are pure up to mutation of their + ;; arguments. This is pure enough for the purposes of + ;; constant folding, but not necessarily for all kinds of + ;; code motion. + car cdr car-safe cdr-safe nth nthcdr last + equal + length safe-length + memq memql member + ;; `assoc' and `assoc-default' are excluded since they are + ;; impure if the test function is (consider `string-match'). + assq rassq rassoc + plist-get lax-plist-get plist-member + aref elt + bool-vector-subsetp + bool-vector-count-population bool-vector-count-consecutive + ))) (while pure-fns (put (car pure-fns) 'pure t) (setq pure-fns (cdr pure-fns))) @@ -1433,10 +1611,7 @@ ;; so we create a copy of it, and replace the addresses with ;; TAGs. (let ((orig-table last-constant)) - (cl-loop for e across constvec - when (eq e last-constant) - do (setq last-constant (copy-hash-table e)) - and return nil) + (setq last-constant (copy-hash-table last-constant)) ;; Replace all addresses with TAGs. (maphash #'(lambda (value offset) (let ((match (assq offset tags))) @@ -1473,10 +1648,10 @@ (setq rest (cdr rest)))) (if tags (error "optimizer error: missed tags %s" tags)) ;; Remove addrs, lap = ( [ (op . arg) | (TAG tagno) ]* ) - (mapcar (function (lambda (elt) - (if (numberp elt) - elt - (cdr elt)))) + (mapcar (lambda (elt) + (if (numberp elt) + elt + (cdr elt))) (nreverse lap)))) @@ -1510,13 +1685,13 @@ byte-current-buffer byte-stack-ref)) (defconst byte-compile-side-effect-free-ops - (nconc + (append '(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-member byte-assq byte-quo byte-rem byte-substring) byte-compile-side-effect-and-error-free-ops)) ;; This crock is because of the way DEFVAR_BOOL variables work. @@ -1574,467 +1749,548 @@ If FOR-EFFECT is non-nil, the return value is assumed to be of no importance." ;; 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. - ;; - ;; 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))) - (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) - (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))) - (byte-compile-log-lap " dup %s discard\t-->\t%s" lap1 lap1) - (setq keep-going t - rest (cdr rest)) - (if (eq 'byte-stack-set (car lap1)) (cl-decf (cdr lap1))) - (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)) - (memq (car lap1) '(byte-goto-if-nil byte-goto-if-not-nil))) - (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 (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) - (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) - ;; If the `byte-constant's cdr is not a cons cell, it has - ;; to be an index into the constant pool); even though - ;; it'll be a constant, that constant is not known yet - ;; (it's typically a free variable of a closure, so will - ;; only be known when the closure will be built at - ;; run-time). - (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)))) - (byte-compile-log-lap " %s %s\t-->\t<deleted>" - lap0 lap1) - (setq rest (cdr rest) - lap (delq lap0 (delq lap1 lap)))) - (t - (byte-compile-log-lap " %s %s\t-->\t%s" - lap0 lap1 - (cons 'byte-goto (cdr lap1))) - (when (memq (car lap1) byte-goto-always-pop-ops) - (setq lap (delq lap0 lap))) - (setcar lap1 'byte-goto))) - (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) - (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) - ;; 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 lap)) - ;; 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)) - (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> - ;; (unless a jump-table is being used, where deleting may affect - ;; other valid case bodies) - ;; - ((and (memq (car lap0) '(byte-goto byte-return)) - (not (memq (car lap1) '(TAG nil))) - ;; FIXME: Instead of deferring simply when jump-tables are - ;; being used, keep a list of tags used for switch tags and - ;; use them instead (see `byte-compile-inline-lapcode'). - (not byte-compile-jump-tables)) - (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)) + (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))) - (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. + ((= 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. + ;; + ;; 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))) + (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) + (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))) + (byte-compile-log-lap " dup %s discard\t-->\t%s" lap1 lap1) + (setq keep-going t + rest (cdr rest)) + (if (eq 'byte-stack-set (car lap1)) (cl-decf (cdr lap1))) + (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)) + (memq (car lap1) '(byte-goto-if-nil byte-goto-if-not-nil))) + (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 (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) + (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) + ;; If the `byte-constant's cdr is not a cons cell, it has + ;; to be an index into the constant pool); even though + ;; it'll be a constant, that constant is not known yet + ;; (it's typically a free variable of a closure, so will + ;; only be known when the closure will be built at + ;; run-time). + (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)))) + (byte-compile-log-lap " %s %s\t-->\t<deleted>" + lap0 lap1) + (setq rest (cdr rest) + lap (delq lap0 (delq lap1 lap)))) + (t + (byte-compile-log-lap " %s %s\t-->\t%s" + lap0 lap1 + (cons 'byte-goto (cdr lap1))) + (when (memq (car lap1) byte-goto-always-pop-ops) + (setq lap (delq lap0 lap))) + (setcar lap1 'byte-goto))) + (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) + (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) + ;; 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 lap)) + ;; 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)) + (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> + ;; (unless a jump-table is being used, where deleting may affect + ;; other valid case bodies) + ;; + ((and (memq (car lap0) '(byte-goto byte-return)) + (not (memq (car lap1) '(TAG nil))) + ;; FIXME: Instead of deferring simply when jump-tables are + ;; being used, keep a list of tags used for switch tags and + ;; use them instead (see `byte-compile-inline-lapcode'). + (not byte-compile-jump-tables)) + (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 ((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 rest (cons nil rest)) + (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)))) - (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 ((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 rest (cons nil rest)) - (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))) - (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). - ;; - ;; 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) 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)) - ) + (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). + ;; + ;; 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) 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)) + + ;; + ;; 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. + (setq lap (delq lap0 lap)) + (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)) + + ;; + ;; discardN-preserve-tos return --> return + ;; dup return --> return + ;; stack-set-N return --> return ; where N is TOS-1 + ;; + ((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. + (setq lap (delq lap0 lap)) + (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) lap))) + (memq (caar tmp) '(byte-discard byte-discardN + byte-discardN-preserve-tos))) + (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 + ;; + ((and (eq (car lap0) 'byte-constant) + (eq (car lap1) 'byte-discardN-preserve-tos)) + (setq keep-going t) + (let ((newdiscard (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 rest (cdr rest))) ) ;; Cleanup stage: @@ -2098,41 +2354,6 @@ If FOR-EFFECT is non-nil, the return value is assumed to be of no importance." (setcdr lap1 (+ (cdr lap1) (cdr lap0)))) ;; - ;; 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. - (setq lap (delq lap0 lap)) - (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)) - - ;; ;; discard/discardN/discardN-preserve-tos-X discard/discardN-Y --> ;; discardN-(X+Y) ;; @@ -2159,20 +2380,6 @@ If FOR-EFFECT is non-nil, the return value is assumed to be of no importance." (setq lap (delq lap0 lap)) (setcdr lap1 (+ (cdr lap0) (cdr lap1))) (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 (car rest))) - - ;; - ;; discardN-preserve-tos return --> return - ;; dup return --> return - ;; stack-set-N return --> return ; where N is TOS-1 - ;; - ((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)))) - ;; The byte-code interpreter will pop the stack for us, so - ;; we can just leave stuff on it. - (setq lap (delq lap0 lap)) - (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 lap1)) ) (setq rest (cdr rest))) (setq byte-compile-maxdepth (+ byte-compile-maxdepth add-depth))) @@ -2186,6 +2393,7 @@ If FOR-EFFECT is non-nil, the return value is assumed to be of no importance." ;; (eval-when-compile (or (byte-code-function-p (symbol-function 'byte-optimize-form)) + (subr-native-elisp-p (symbol-function 'byte-optimize-form)) (assq 'byte-code (symbol-function 'byte-optimize-form)) (let ((byte-optimize nil) (byte-compile-warnings nil)) @@ -2195,7 +2403,7 @@ If FOR-EFFECT is non-nil, the return value is assumed to be of no importance." (or noninteractive (message "compiling %s...done" x))) '(byte-optimize-form byte-optimize-body - byte-optimize-predicate + byte-optimize-constant-args byte-optimize-binary-predicate ;; Inserted some more than necessary, to speed it up. byte-optimize-form-code-walker |