Mercurial > hg > xemacs-beta
comparison lisp/byte-optimize.el @ 209:41ff10fd062f r20-4b3
Import from CVS: tag r20-4b3
| author | cvs |
|---|---|
| date | Mon, 13 Aug 2007 10:04:58 +0200 |
| parents | |
| children | 51092a27c943 |
comparison
equal
deleted
inserted
replaced
| 208:f427b8ec4379 | 209:41ff10fd062f |
|---|---|
| 1 ;;; byte-opt.el --- the optimization passes of the emacs-lisp byte compiler. | |
| 2 | |
| 3 ;;; Copyright (c) 1991, 1994 Free Software Foundation, Inc. | |
| 4 | |
| 5 ;; Author: Jamie Zawinski <jwz@netscape.com> | |
| 6 ;; Hallvard Furuseth <hbf@ulrik.uio.no> | |
| 7 ;; Keywords: internal | |
| 8 | |
| 9 ;; This file is part of XEmacs. | |
| 10 | |
| 11 ;; XEmacs is free software; you can redistribute it and/or modify it | |
| 12 ;; under the terms of the GNU General Public License as published by | |
| 13 ;; the Free Software Foundation; either version 2, or (at your option) | |
| 14 ;; any later version. | |
| 15 | |
| 16 ;; XEmacs is distributed in the hope that it will be useful, but | |
| 17 ;; WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 19 ;; General Public License for more details. | |
| 20 | |
| 21 ;; You should have received a copy of the GNU General Public License | |
| 22 ;; along with XEmacs; see the file COPYING. If not, write to the | |
| 23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
| 24 ;; Boston, MA 02111-1307, USA. | |
| 25 | |
| 26 ;;; Synched up with: FSF 19.30. | |
| 27 | |
| 28 ;;; Commentary: | |
| 29 | |
| 30 ;;; ======================================================================== | |
| 31 ;;; "No matter how hard you try, you can't make a racehorse out of a pig. | |
| 32 ;;; You can, however, make a faster pig." | |
| 33 ;;; | |
| 34 ;;; Or, to put it another way, the emacs byte compiler is a VW Bug. This code | |
| 35 ;;; makes it be a VW Bug with fuel injection and a turbocharger... You're | |
| 36 ;;; still not going to make it go faster than 70 mph, but it might be easier | |
| 37 ;;; to get it there. | |
| 38 ;;; | |
| 39 | |
| 40 ;;; TO DO: | |
| 41 ;;; | |
| 42 ;;; (apply '(lambda (x &rest y) ...) 1 (foo)) | |
| 43 ;;; | |
| 44 ;;; maintain a list of functions known not to access any global variables | |
| 45 ;;; (actually, give them a 'dynamically-safe property) and then | |
| 46 ;;; (let ( v1 v2 ... vM vN ) <...dynamically-safe...> ) ==> | |
| 47 ;;; (let ( v1 v2 ... vM ) vN <...dynamically-safe...> ) | |
| 48 ;;; by recursing on this, we might be able to eliminate the entire let. | |
| 49 ;;; However certain variables should never have their bindings optimized | |
| 50 ;;; away, because they affect everything. | |
| 51 ;;; (put 'debug-on-error 'binding-is-magic t) | |
| 52 ;;; (put 'debug-on-abort 'binding-is-magic t) | |
| 53 ;;; (put 'debug-on-next-call 'binding-is-magic t) | |
| 54 ;;; (put 'mocklisp-arguments 'binding-is-magic t) | |
| 55 ;;; (put 'inhibit-quit 'binding-is-magic t) | |
| 56 ;;; (put 'quit-flag 'binding-is-magic t) | |
| 57 ;;; (put 't 'binding-is-magic t) | |
| 58 ;;; (put 'nil 'binding-is-magic t) | |
| 59 ;;; possibly also | |
| 60 ;;; (put 'gc-cons-threshold 'binding-is-magic t) | |
| 61 ;;; (put 'track-mouse 'binding-is-magic t) | |
| 62 ;;; others? | |
| 63 ;;; | |
| 64 ;;; Simple defsubsts often produce forms like | |
| 65 ;;; (let ((v1 (f1)) (v2 (f2)) ...) | |
| 66 ;;; (FN v1 v2 ...)) | |
| 67 ;;; It would be nice if we could optimize this to | |
| 68 ;;; (FN (f1) (f2) ...) | |
| 69 ;;; but we can't unless FN is dynamically-safe (it might be dynamically | |
| 70 ;;; referring to the bindings that the lambda arglist established.) | |
| 71 ;;; One of the uncountable lossages introduced by dynamic scope... | |
| 72 ;;; | |
| 73 ;;; Maybe there should be a control-structure that says "turn on | |
| 74 ;;; fast-and-loose type-assumptive optimizations here." Then when | |
| 75 ;;; we see a form like (car foo) we can from then on assume that | |
| 76 ;;; the variable foo is of type cons, and optimize based on that. | |
| 77 ;;; But, this won't win much because of (you guessed it) dynamic | |
| 78 ;;; scope. Anything down the stack could change the value. | |
| 79 ;;; (Another reason it doesn't work is that it is perfectly valid | |
| 80 ;;; to call car with a null argument.) A better approach might | |
| 81 ;;; be to allow type-specification of the form | |
| 82 ;;; (put 'foo 'arg-types '(float (list integer) dynamic)) | |
| 83 ;;; (put 'foo 'result-type 'bool) | |
| 84 ;;; It should be possible to have these types checked to a certain | |
| 85 ;;; degree. | |
| 86 ;;; | |
| 87 ;;; collapse common subexpressions | |
| 88 ;;; | |
| 89 ;;; It would be nice if redundant sequences could be factored out as well, | |
| 90 ;;; when they are known to have no side-effects: | |
| 91 ;;; (list (+ a b c) (+ a b c)) --> a b add c add dup list-2 | |
| 92 ;;; but beware of traps like | |
| 93 ;;; (cons (list x y) (list x y)) | |
| 94 ;;; | |
| 95 ;;; Tail-recursion elimination is not really possible in Emacs Lisp. | |
| 96 ;;; Tail-recursion elimination is almost always impossible when all variables | |
| 97 ;;; have dynamic scope, but given that the "return" byteop requires the | |
| 98 ;;; binding stack to be empty (rather than emptying it itself), there can be | |
| 99 ;;; no truly tail-recursive Emacs Lisp functions that take any arguments or | |
| 100 ;;; make any bindings. | |
| 101 ;;; | |
| 102 ;;; Here is an example of an Emacs Lisp function which could safely be | |
| 103 ;;; byte-compiled tail-recursively: | |
| 104 ;;; | |
| 105 ;;; (defun tail-map (fn list) | |
| 106 ;;; (cond (list | |
| 107 ;;; (funcall fn (car list)) | |
| 108 ;;; (tail-map fn (cdr list))))) | |
| 109 ;;; | |
| 110 ;;; However, if there was even a single let-binding around the COND, | |
| 111 ;;; it could not be byte-compiled, because there would be an "unbind" | |
| 112 ;;; byte-op between the final "call" and "return." Adding a | |
| 113 ;;; Bunbind_all byteop would fix this. | |
| 114 ;;; | |
| 115 ;;; (defun foo (x y z) ... (foo a b c)) | |
| 116 ;;; ... (const foo) (varref a) (varref b) (varref c) (call 3) END: (return) | |
| 117 ;;; ... (varref a) (varbind x) (varref b) (varbind y) (varref c) (varbind z) (goto 0) END: (unbind-all) (return) | |
| 118 ;;; ... (varref a) (varset x) (varref b) (varset y) (varref c) (varset z) (goto 0) END: (return) | |
| 119 ;;; | |
| 120 ;;; this also can be considered tail recursion: | |
| 121 ;;; | |
| 122 ;;; ... (const foo) (varref a) (call 1) (goto X) ... X: (return) | |
| 123 ;;; could generalize this by doing the optimization | |
| 124 ;;; (goto X) ... X: (return) --> (return) | |
| 125 ;;; | |
| 126 ;;; But this doesn't solve all of the problems: although by doing tail- | |
| 127 ;;; recursion elimination in this way, the call-stack does not grow, the | |
| 128 ;;; binding-stack would grow with each recursive step, and would eventually | |
| 129 ;;; overflow. I don't believe there is any way around this without lexical | |
| 130 ;;; scope. | |
| 131 ;;; | |
| 132 ;;; Wouldn't it be nice if Emacs Lisp had lexical scope. | |
| 133 ;;; | |
| 134 ;;; Idea: the form (lexical-scope) in a file means that the file may be | |
| 135 ;;; compiled lexically. This proclamation is file-local. Then, within | |
| 136 ;;; that file, "let" would establish lexical bindings, and "let-dynamic" | |
| 137 ;;; would do things the old way. (Or we could use CL "declare" forms.) | |
| 138 ;;; We'd have to notice defvars and defconsts, since those variables should | |
| 139 ;;; always be dynamic, and attempting to do a lexical binding of them | |
| 140 ;;; should simply do a dynamic binding instead. | |
| 141 ;;; But! We need to know about variables that were not necessarily defvarred | |
| 142 ;;; in the file being compiled (doing a boundp check isn't good enough.) | |
| 143 ;;; Fdefvar() would have to be modified to add something to the plist. | |
| 144 ;;; | |
| 145 ;;; A major disadvantage of this scheme is that the interpreter and compiler | |
| 146 ;;; would have different semantics for files compiled with (dynamic-scope). | |
| 147 ;;; Since this would be a file-local optimization, there would be no way to | |
| 148 ;;; modify the interpreter to obey this (unless the loader was hacked | |
| 149 ;;; in some grody way, but that's a really bad idea.) | |
| 150 ;;; | |
| 151 ;;; HA! HA! HA! RMS removed the following paragraph from his version of | |
| 152 ;;; byte-opt.el, proving once again his stubborn refusal to accept any | |
| 153 ;;; developments in computer science that occurred after the late 1970's. | |
| 154 ;;; | |
| 155 ;;; Really the Right Thing is to make lexical scope the default across | |
| 156 ;;; the board, in the interpreter and compiler, and just FIX all of | |
| 157 ;;; the code that relies on dynamic scope of non-defvarred variables. | |
| 158 | |
| 159 ;; Other things to consider: | |
| 160 | |
| 161 ;;;;; Associative math should recognize subcalls to identical function: | |
| 162 ;;;(disassemble (lambda (x) (+ (+ (foo) 1) (+ (bar) 2)))) | |
| 163 ;;;;; This should generate the same as (1+ x) and (1- x) | |
| 164 | |
| 165 ;;;(disassemble (lambda (x) (cons (+ x 1) (- x 1)))) | |
| 166 ;;;;; An awful lot of functions always return a non-nil value. If they're | |
| 167 ;;;;; error free also they may act as true-constants. | |
| 168 | |
| 169 ;;;(disassemble (lambda (x) (and (point) (foo)))) | |
| 170 ;;;;; When | |
| 171 ;;;;; - all but one arguments to a function are constant | |
| 172 ;;;;; - the non-constant argument is an if-expression (cond-expression?) | |
| 173 ;;;;; then the outer function can be distributed. If the guarding | |
| 174 ;;;;; condition is side-effect-free [assignment-free] then the other | |
| 175 ;;;;; arguments may be any expressions. Since, however, the code size | |
| 176 ;;;;; can increase this way they should be "simple". Compare: | |
| 177 | |
| 178 ;;;(disassemble (lambda (x) (eq (if (point) 'a 'b) 'c))) | |
| 179 ;;;(disassemble (lambda (x) (if (point) (eq 'a 'c) (eq 'b 'c)))) | |
| 180 | |
| 181 ;;;;; (car (cons A B)) -> (progn B A) | |
| 182 ;;;(disassemble (lambda (x) (car (cons (foo) 42)))) | |
| 183 | |
| 184 ;;;;; (cdr (cons A B)) -> (progn A B) | |
| 185 ;;;(disassemble (lambda (x) (cdr (cons 42 (foo))))) | |
| 186 | |
| 187 ;;;;; (car (list A B ...)) -> (progn B ... A) | |
| 188 ;;;(disassemble (lambda (x) (car (list (foo) 42 (bar))))) | |
| 189 | |
| 190 ;;;;; (cdr (list A B ...)) -> (progn A (list B ...)) | |
| 191 ;;;(disassemble (lambda (x) (cdr (list 42 (foo) (bar))))) | |
| 192 | |
| 193 | |
| 194 ;;; Code: | |
| 195 | |
| 196 (require 'byte-compile "bytecomp") | |
| 197 | |
| 198 (defun byte-compile-log-lap-1 (format &rest args) | |
| 199 (if (aref byte-code-vector 0) | |
| 200 (error "The old version of the disassembler is loaded. Reload new-bytecomp as well.")) | |
| 201 (byte-compile-log-1 | |
| 202 (apply 'format format | |
| 203 (let (c a) | |
| 204 (mapcar '(lambda (arg) | |
| 205 (if (not (consp arg)) | |
| 206 (if (and (symbolp arg) | |
| 207 (string-match "^byte-" (symbol-name arg))) | |
| 208 (intern (substring (symbol-name arg) 5)) | |
| 209 arg) | |
| 210 (if (integerp (setq c (car arg))) | |
| 211 (error "non-symbolic byte-op %s" c)) | |
| 212 (if (eq c 'TAG) | |
| 213 (setq c arg) | |
| 214 (setq a (cond ((memq c byte-goto-ops) | |
| 215 (car (cdr (cdr arg)))) | |
| 216 ((memq c byte-constref-ops) | |
| 217 (car (cdr arg))) | |
| 218 (t (cdr arg)))) | |
| 219 (setq c (symbol-name c)) | |
| 220 (if (string-match "^byte-." c) | |
| 221 (setq c (intern (substring c 5))))) | |
| 222 (if (eq c 'constant) (setq c 'const)) | |
| 223 (if (and (eq (cdr arg) 0) | |
| 224 (not (memq c '(unbind call const)))) | |
| 225 c | |
| 226 (format "(%s %s)" c a)))) | |
| 227 args))))) | |
| 228 | |
| 229 (defmacro byte-compile-log-lap (format-string &rest args) | |
| 230 (list 'and | |
| 231 '(memq byte-optimize-log '(t byte)) | |
| 232 (cons 'byte-compile-log-lap-1 | |
| 233 (cons format-string args)))) | |
| 234 | |
| 235 | |
| 236 ;;; byte-compile optimizers to support inlining | |
| 237 | |
| 238 (put 'inline 'byte-optimizer 'byte-optimize-inline-handler) | |
| 239 | |
| 240 (defun byte-optimize-inline-handler (form) | |
| 241 "byte-optimize-handler for the `inline' special-form." | |
| 242 (cons 'progn | |
| 243 (mapcar | |
| 244 '(lambda (sexp) | |
| 245 (let ((fn (car-safe sexp))) | |
| 246 (if (and (symbolp fn) | |
| 247 (or (cdr (assq fn byte-compile-function-environment)) | |
| 248 (and (fboundp fn) | |
| 249 (not (or (cdr (assq fn byte-compile-macro-environment)) | |
| 250 (and (consp (setq fn (symbol-function fn))) | |
| 251 (eq (car fn) 'macro)) | |
| 252 (subrp fn)))))) | |
| 253 (byte-compile-inline-expand sexp) | |
| 254 sexp))) | |
| 255 (cdr form)))) | |
| 256 | |
| 257 | |
| 258 ;; Splice the given lap code into the current instruction stream. | |
| 259 ;; If it has any labels in it, you're responsible for making sure there | |
| 260 ;; are no collisions, and that byte-compile-tag-number is reasonable | |
| 261 ;; after this is spliced in. The provided list is destroyed. | |
| 262 (defun byte-inline-lapcode (lap) | |
| 263 (setq byte-compile-output (nconc (nreverse lap) byte-compile-output))) | |
| 264 | |
| 265 | |
| 266 (defun byte-compile-inline-expand (form) | |
| 267 (let* ((name (car form)) | |
| 268 (fn (or (cdr (assq name byte-compile-function-environment)) | |
| 269 (and (fboundp name) (symbol-function name))))) | |
| 270 (if (null fn) | |
| 271 (progn | |
| 272 (byte-compile-warn "attempt to inline %s before it was defined" name) | |
| 273 form) | |
| 274 ;; else | |
| 275 (if (and (consp fn) (eq (car fn) 'autoload)) | |
| 276 (progn | |
| 277 (load (nth 1 fn)) | |
| 278 (setq fn (or (cdr (assq name byte-compile-function-environment)) | |
| 279 (and (fboundp name) (symbol-function name)))))) | |
| 280 (if (and (consp fn) (eq (car fn) 'autoload)) | |
| 281 (error "file \"%s\" didn't define \"%s\"" (nth 1 fn) name)) | |
| 282 (if (symbolp fn) | |
| 283 (byte-compile-inline-expand (cons fn (cdr form))) | |
| 284 (if (compiled-function-p fn) | |
| 285 (progn | |
| 286 (fetch-bytecode fn) | |
| 287 (cons (list 'lambda (compiled-function-arglist fn) | |
| 288 (list 'byte-code | |
| 289 (compiled-function-instructions fn) | |
| 290 (compiled-function-constants fn) | |
| 291 (compiled-function-stack-depth fn))) | |
| 292 (cdr form))) | |
| 293 (if (not (eq (car fn) 'lambda)) (error "%s is not a lambda" name)) | |
| 294 (cons fn (cdr form))))))) | |
| 295 | |
| 296 ;;; ((lambda ...) ...) | |
| 297 ;;; | |
| 298 (defun byte-compile-unfold-lambda (form &optional name) | |
| 299 (or name (setq name "anonymous lambda")) | |
| 300 (let ((lambda (car form)) | |
| 301 (values (cdr form))) | |
| 302 (if (compiled-function-p lambda) | |
| 303 (setq lambda (list 'lambda (compiled-function-arglist lambda) | |
| 304 (list 'byte-code | |
| 305 (compiled-function-instructions lambda) | |
| 306 (compiled-function-constants lambda) | |
| 307 (compiled-function-stack-depth lambda))))) | |
| 308 (let ((arglist (nth 1 lambda)) | |
| 309 (body (cdr (cdr lambda))) | |
| 310 optionalp restp | |
| 311 bindings) | |
| 312 (if (and (stringp (car body)) (cdr body)) | |
| 313 (setq body (cdr body))) | |
| 314 (if (and (consp (car body)) (eq 'interactive (car (car body)))) | |
| 315 (setq body (cdr body))) | |
| 316 (while arglist | |
| 317 (cond ((eq (car arglist) '&optional) | |
| 318 ;; ok, I'll let this slide because funcall_lambda() does... | |
| 319 ;; (if optionalp (error "multiple &optional keywords in %s" name)) | |
| 320 (if restp (error "&optional found after &rest in %s" name)) | |
| 321 (if (null (cdr arglist)) | |
| 322 (error "nothing after &optional in %s" name)) | |
| 323 (setq optionalp t)) | |
| 324 ((eq (car arglist) '&rest) | |
| 325 ;; ...but it is by no stretch of the imagination a reasonable | |
| 326 ;; thing that funcall_lambda() allows (&rest x y) and | |
| 327 ;; (&rest x &optional y) in arglists. | |
| 328 (if (null (cdr arglist)) | |
| 329 (error "nothing after &rest in %s" name)) | |
| 330 (if (cdr (cdr arglist)) | |
| 331 (error "multiple vars after &rest in %s" name)) | |
| 332 (setq restp t)) | |
| 333 (restp | |
| 334 (setq bindings (cons (list (car arglist) | |
| 335 (and values (cons 'list values))) | |
| 336 bindings) | |
| 337 values nil)) | |
| 338 ((and (not optionalp) (null values)) | |
| 339 (byte-compile-warn "attempt to open-code %s with too few arguments" name) | |
| 340 (setq arglist nil values 'too-few)) | |
| 341 (t | |
| 342 (setq bindings (cons (list (car arglist) (car values)) | |
| 343 bindings) | |
| 344 values (cdr values)))) | |
| 345 (setq arglist (cdr arglist))) | |
| 346 (if values | |
| 347 (progn | |
| 348 (or (eq values 'too-few) | |
| 349 (byte-compile-warn | |
| 350 "attempt to open-code %s with too many arguments" name)) | |
| 351 form) | |
| 352 (let ((newform | |
| 353 (if bindings | |
| 354 (cons 'let (cons (nreverse bindings) body)) | |
| 355 (cons 'progn body)))) | |
| 356 (byte-compile-log " %s\t==>\t%s" form newform) | |
| 357 newform))))) | |
| 358 | |
| 359 | |
| 360 ;;; implementing source-level optimizers | |
| 361 | |
| 362 (defun byte-optimize-form-code-walker (form for-effect) | |
| 363 ;; | |
| 364 ;; For normal function calls, We can just mapcar the optimizer the cdr. But | |
| 365 ;; we need to have special knowledge of the syntax of the special forms | |
| 366 ;; like let and defun (that's why they're special forms :-). (Actually, | |
| 367 ;; the important aspect is that they are subrs that don't evaluate all of | |
| 368 ;; their args.) | |
| 369 ;; | |
| 370 (let ((fn (car-safe form)) | |
| 371 tmp) | |
| 372 (cond ((not (consp form)) | |
| 373 (if (not (and for-effect | |
| 374 (or byte-compile-delete-errors | |
| 375 (not (symbolp form)) | |
| 376 (eq form t)))) | |
| 377 form)) | |
| 378 ((eq fn 'quote) | |
| 379 (if (cdr (cdr form)) | |
| 380 (byte-compile-warn "malformed quote form: %s" | |
| 381 (prin1-to-string form))) | |
| 382 ;; map (quote nil) to nil to simplify optimizer logic. | |
| 383 ;; map quoted constants to nil if for-effect (just because). | |
| 384 (and (nth 1 form) | |
| 385 (not for-effect) | |
| 386 form)) | |
| 387 ((or (compiled-function-p fn) | |
| 388 (eq 'lambda (car-safe fn))) | |
| 389 (byte-compile-unfold-lambda form)) | |
| 390 ((memq fn '(let let*)) | |
| 391 ;; recursively enter the optimizer for the bindings and body | |
| 392 ;; of a let or let*. This for depth-firstness: forms that | |
| 393 ;; are more deeply nested are optimized first. | |
| 394 (cons fn | |
| 395 (cons | |
| 396 (mapcar '(lambda (binding) | |
| 397 (if (symbolp binding) | |
| 398 binding | |
| 399 (if (cdr (cdr binding)) | |
| 400 (byte-compile-warn "malformed let binding: %s" | |
| 401 (prin1-to-string binding))) | |
| 402 (list (car binding) | |
| 403 (byte-optimize-form (nth 1 binding) nil)))) | |
| 404 (nth 1 form)) | |
| 405 (byte-optimize-body (cdr (cdr form)) for-effect)))) | |
| 406 ((eq fn 'cond) | |
| 407 (cons fn | |
| 408 (mapcar '(lambda (clause) | |
| 409 (if (consp clause) | |
| 410 (cons | |
| 411 (byte-optimize-form (car clause) nil) | |
| 412 (byte-optimize-body (cdr clause) for-effect)) | |
| 413 (byte-compile-warn "malformed cond form: %s" | |
| 414 (prin1-to-string clause)) | |
| 415 clause)) | |
| 416 (cdr form)))) | |
| 417 ((eq fn 'progn) | |
| 418 ;; as an extra added bonus, this simplifies (progn <x>) --> <x> | |
| 419 (if (cdr (cdr form)) | |
| 420 (progn | |
| 421 (setq tmp (byte-optimize-body (cdr form) for-effect)) | |
| 422 (if (cdr tmp) (cons 'progn tmp) (car tmp))) | |
| 423 (byte-optimize-form (nth 1 form) for-effect))) | |
| 424 ((eq fn 'prog1) | |
| 425 (if (cdr (cdr form)) | |
| 426 (cons 'prog1 | |
| 427 (cons (byte-optimize-form (nth 1 form) for-effect) | |
| 428 (byte-optimize-body (cdr (cdr form)) t))) | |
| 429 (byte-optimize-form (nth 1 form) for-effect))) | |
| 430 ((eq fn 'prog2) | |
| 431 (cons 'prog2 | |
| 432 (cons (byte-optimize-form (nth 1 form) t) | |
| 433 (cons (byte-optimize-form (nth 2 form) for-effect) | |
| 434 (byte-optimize-body (cdr (cdr (cdr form))) t))))) | |
| 435 | |
| 436 ((memq fn '(save-excursion save-restriction save-current-buffer)) | |
| 437 ;; those subrs which have an implicit progn; it's not quite good | |
| 438 ;; enough to treat these like normal function calls. | |
| 439 ;; This can turn (save-excursion ...) into (save-excursion) which | |
| 440 ;; will be optimized away in the lap-optimize pass. | |
| 441 (cons fn (byte-optimize-body (cdr form) for-effect))) | |
| 442 | |
| 443 ((eq fn 'with-output-to-temp-buffer) | |
| 444 ;; this is just like the above, except for the first argument. | |
| 445 (cons fn | |
| 446 (cons | |
| 447 (byte-optimize-form (nth 1 form) nil) | |
| 448 (byte-optimize-body (cdr (cdr form)) for-effect)))) | |
| 449 | |
| 450 ((eq fn 'if) | |
| 451 (cons fn | |
| 452 (cons (byte-optimize-form (nth 1 form) nil) | |
| 453 (cons | |
| 454 (byte-optimize-form (nth 2 form) for-effect) | |
| 455 (byte-optimize-body (nthcdr 3 form) for-effect))))) | |
| 456 | |
| 457 ((memq fn '(and or)) ; remember, and/or are control structures. | |
| 458 ;; take forms off the back until we can't any more. | |
| 459 ;; In the future it could conceivably be a problem that the | |
| 460 ;; subexpressions of these forms are optimized in the reverse | |
| 461 ;; order, but it's ok for now. | |
| 462 (if for-effect | |
| 463 (let ((backwards (reverse (cdr form)))) | |
| 464 (while (and backwards | |
| 465 (null (setcar backwards | |
| 466 (byte-optimize-form (car backwards) | |
| 467 for-effect)))) | |
| 468 (setq backwards (cdr backwards))) | |
| 469 (if (and (cdr form) (null backwards)) | |
| 470 (byte-compile-log | |
| 471 " all subforms of %s called for effect; deleted" form)) | |
| 472 (and backwards | |
| 473 (cons fn (nreverse backwards)))) | |
| 474 (cons fn (mapcar 'byte-optimize-form (cdr form))))) | |
| 475 | |
| 476 ((eq fn 'interactive) | |
| 477 (byte-compile-warn "misplaced interactive spec: %s" | |
| 478 (prin1-to-string form)) | |
| 479 nil) | |
| 480 | |
| 481 ((memq fn '(defun defmacro function | |
| 482 condition-case save-window-excursion)) | |
| 483 ;; These forms are compiled as constants or by breaking out | |
| 484 ;; all the subexpressions and compiling them separately. | |
| 485 form) | |
| 486 | |
| 487 ((eq fn 'unwind-protect) | |
| 488 ;; the "protected" part of an unwind-protect is compiled (and thus | |
| 489 ;; optimized) as a top-level form, so don't do it here. But the | |
| 490 ;; non-protected part has the same for-effect status as the | |
| 491 ;; unwind-protect itself. (The protected part is always for effect, | |
| 492 ;; but that isn't handled properly yet.) | |
| 493 (cons fn | |
| 494 (cons (byte-optimize-form (nth 1 form) for-effect) | |
| 495 (cdr (cdr form))))) | |
| 496 | |
| 497 ((eq fn 'catch) | |
| 498 ;; the body of a catch is compiled (and thus optimized) as a | |
| 499 ;; top-level form, so don't do it here. The tag is never | |
| 500 ;; for-effect. The body should have the same for-effect status | |
| 501 ;; as the catch form itself, but that isn't handled properly yet. | |
| 502 (cons fn | |
| 503 (cons (byte-optimize-form (nth 1 form) nil) | |
| 504 (cdr (cdr form))))) | |
| 505 | |
| 506 ;; If optimization is on, this is the only place that macros are | |
| 507 ;; expanded. If optimization is off, then macroexpansion happens | |
| 508 ;; in byte-compile-form. Otherwise, the macros are already expanded | |
| 509 ;; by the time that is reached. | |
| 510 ((not (eq form | |
| 511 (setq form (macroexpand form | |
| 512 byte-compile-macro-environment)))) | |
| 513 (byte-optimize-form form for-effect)) | |
| 514 | |
| 515 ((not (symbolp fn)) | |
| 516 (or (eq 'mocklisp (car-safe fn)) ; ha! | |
| 517 (byte-compile-warn "%s is a malformed function" | |
| 518 (prin1-to-string fn))) | |
| 519 form) | |
| 520 | |
| 521 ((and for-effect (setq tmp (get fn 'side-effect-free)) | |
| 522 (or byte-compile-delete-errors | |
| 523 (eq tmp 'error-free) | |
| 524 (progn | |
| 525 (byte-compile-warn "%s called for effect" | |
| 526 (prin1-to-string form)) | |
| 527 nil))) | |
| 528 (byte-compile-log " %s called for effect; deleted" fn) | |
| 529 ;; appending a nil here might not be necessary, but it can't hurt. | |
| 530 (byte-optimize-form | |
| 531 (cons 'progn (append (cdr form) '(nil))) t)) | |
| 532 | |
| 533 (t | |
| 534 ;; Otherwise, no args can be considered to be for-effect, | |
| 535 ;; even if the called function is for-effect, because we | |
| 536 ;; don't know anything about that function. | |
| 537 (cons fn (mapcar 'byte-optimize-form (cdr form))))))) | |
| 538 | |
| 539 | |
| 540 (defun byte-optimize-form (form &optional for-effect) | |
| 541 "The source-level pass of the optimizer." | |
| 542 ;; | |
| 543 ;; First, optimize all sub-forms of this one. | |
| 544 (setq form (byte-optimize-form-code-walker form for-effect)) | |
| 545 ;; | |
| 546 ;; after optimizing all subforms, optimize this form until it doesn't | |
| 547 ;; optimize any further. This means that some forms will be passed through | |
| 548 ;; the optimizer many times, but that's necessary to make the for-effect | |
| 549 ;; processing do as much as possible. | |
| 550 ;; | |
| 551 (let (opt new) | |
| 552 (if (and (consp form) | |
| 553 (symbolp (car form)) | |
| 554 (or (and for-effect | |
| 555 ;; we don't have any of these yet, but we might. | |
| 556 (setq opt (get (car form) 'byte-for-effect-optimizer))) | |
| 557 (setq opt (get (car form) 'byte-optimizer))) | |
| 558 (not (eq form (setq new (funcall opt form))))) | |
| 559 (progn | |
| 560 ;; (if (equal form new) (error "bogus optimizer -- %s" opt)) | |
| 561 (byte-compile-log " %s\t==>\t%s" form new) | |
| 562 (setq new (byte-optimize-form new for-effect)) | |
| 563 new) | |
| 564 form))) | |
| 565 | |
| 566 | |
| 567 (defun byte-optimize-body (forms all-for-effect) | |
| 568 ;; optimize the cdr of a progn or implicit progn; all forms is a list of | |
| 569 ;; forms, all but the last of which are optimized with the assumption that | |
| 570 ;; they are being called for effect. the last is for-effect as well if | |
| 571 ;; all-for-effect is true. returns a new list of forms. | |
| 572 (let ((rest forms) | |
| 573 (result nil) | |
| 574 fe new) | |
| 575 (while rest | |
| 576 (setq fe (or all-for-effect (cdr rest))) | |
| 577 (setq new (and (car rest) (byte-optimize-form (car rest) fe))) | |
| 578 (if (or new (not fe)) | |
| 579 (setq result (cons new result))) | |
| 580 (setq rest (cdr rest))) | |
| 581 (nreverse result))) | |
| 582 | |
| 583 | |
| 584 ;;; some source-level optimizers | |
| 585 ;;; | |
| 586 ;;; when writing optimizers, be VERY careful that the optimizer returns | |
| 587 ;;; something not EQ to its argument if and ONLY if it has made a change. | |
| 588 ;;; This implies that you cannot simply destructively modify the list; | |
| 589 ;;; you must return something not EQ to it if you make an optimization. | |
| 590 ;;; | |
| 591 ;;; It is now safe to optimize code such that it introduces new bindings. | |
| 592 | |
| 593 ;; I'd like this to be a defsubst, but let's not be self-referential... | |
| 594 (defmacro byte-compile-trueconstp (form) | |
| 595 ;; Returns non-nil if FORM is a non-nil constant. | |
| 596 (` (cond ((consp (, form)) (eq (car (, form)) 'quote)) | |
| 597 ((not (symbolp (, form)))) | |
| 598 ((eq (, form) t))))) | |
| 599 | |
| 600 ;; If the function is being called with constant numeric args, | |
| 601 ;; evaluate as much as possible at compile-time. This optimizer | |
| 602 ;; assumes that the function is associative, like + or *. | |
| 603 (defun byte-optimize-associative-math (form) | |
| 604 (let ((args nil) | |
| 605 (constants nil) | |
| 606 (rest (cdr form))) | |
| 607 (while rest | |
| 608 (if (numberp (car rest)) | |
| 609 (setq constants (cons (car rest) constants)) | |
| 610 (setq args (cons (car rest) args))) | |
| 611 (setq rest (cdr rest))) | |
| 612 (if (cdr constants) | |
| 613 (if args | |
| 614 (list (car form) | |
| 615 (apply (car form) constants) | |
| 616 (if (cdr args) | |
| 617 (cons (car form) (nreverse args)) | |
| 618 (car args))) | |
| 619 (apply (car form) constants)) | |
| 620 form))) | |
| 621 | |
| 622 ;; If the function is being called with constant numeric args, | |
| 623 ;; evaluate as much as possible at compile-time. This optimizer | |
| 624 ;; assumes that the function satisfies | |
| 625 ;; (op x1 x2 ... xn) == (op ...(op (op x1 x2) x3) ...xn) | |
| 626 ;; like - and /. | |
| 627 (defun byte-optimize-nonassociative-math (form) | |
| 628 (if (or (not (numberp (car (cdr form)))) | |
| 629 (not (numberp (car (cdr (cdr form)))))) | |
| 630 form | |
| 631 (let ((constant (car (cdr form))) | |
| 632 (rest (cdr (cdr form)))) | |
| 633 (while (numberp (car rest)) | |
| 634 (setq constant (funcall (car form) constant (car rest)) | |
| 635 rest (cdr rest))) | |
| 636 (if rest | |
| 637 (cons (car form) (cons constant rest)) | |
| 638 constant)))) | |
| 639 | |
| 640 ;;(defun byte-optimize-associative-two-args-math (form) | |
| 641 ;; (setq form (byte-optimize-associative-math form)) | |
| 642 ;; (if (consp form) | |
| 643 ;; (byte-optimize-two-args-left form) | |
| 644 ;; form)) | |
| 645 | |
| 646 ;;(defun byte-optimize-nonassociative-two-args-math (form) | |
| 647 ;; (setq form (byte-optimize-nonassociative-math form)) | |
| 648 ;; (if (consp form) | |
| 649 ;; (byte-optimize-two-args-right form) | |
| 650 ;; form)) | |
| 651 | |
| 652 ;; jwz: (byte-optimize-approx-equal 0.0 0.0) was returning nil | |
| 653 ;; in xemacs 19.15 because it used < instead of <=. | |
| 654 (defun byte-optimize-approx-equal (x y) | |
| 655 (<= (* (abs (- x y)) 100) (abs (+ x y)))) | |
| 656 | |
| 657 ;; Collect all the constants from FORM, after the STARTth arg, | |
| 658 ;; and apply FUN to them to make one argument at the end. | |
| 659 ;; For functions that can handle floats, that optimization | |
| 660 ;; can be incorrect because reordering can cause an overflow | |
| 661 ;; that would otherwise be avoided by encountering an arg that is a float. | |
| 662 ;; We avoid this problem by (1) not moving float constants and | |
| 663 ;; (2) not moving anything if it would cause an overflow. | |
| 664 (defun byte-optimize-delay-constants-math (form start fun) | |
| 665 ;; Merge all FORM's constants from number START, call FUN on them | |
| 666 ;; and put the result at the end. | |
| 667 (let ((rest (nthcdr (1- start) form)) | |
| 668 (orig form) | |
| 669 ;; t means we must check for overflow. | |
| 670 (overflow (memq fun '(+ *)))) | |
| 671 (while (cdr (setq rest (cdr rest))) | |
| 672 (if (integerp (car rest)) | |
| 673 (let (constants) | |
| 674 (setq form (copy-sequence form) | |
| 675 rest (nthcdr (1- start) form)) | |
| 676 (while (setq rest (cdr rest)) | |
| 677 (cond ((integerp (car rest)) | |
| 678 (setq constants (cons (car rest) constants)) | |
| 679 (setcar rest nil)))) | |
| 680 ;; If necessary, check now for overflow | |
| 681 ;; that might be caused by reordering. | |
| 682 (if (and overflow | |
| 683 ;; We have overflow if the result of doing the arithmetic | |
| 684 ;; on floats is not even close to the result | |
| 685 ;; of doing it on integers. | |
| 686 (not (byte-optimize-approx-equal | |
| 687 (apply fun (mapcar 'float constants)) | |
| 688 (float (apply fun constants))))) | |
| 689 (setq form orig) | |
| 690 (setq form (nconc (delq nil form) | |
| 691 (list (apply fun (nreverse constants))))))))) | |
| 692 form)) | |
| 693 | |
| 694 (defun byte-optimize-plus (form) | |
| 695 (setq form (byte-optimize-delay-constants-math form 1 '+)) | |
| 696 (if (memq 0 form) (setq form (delq 0 (copy-sequence form)))) | |
| 697 ;;(setq form (byte-optimize-associative-two-args-math form)) | |
| 698 (cond ((null (cdr form)) | |
| 699 (condition-case () | |
| 700 (eval form) | |
| 701 (error form))) | |
| 702 | |
| 703 ;; `add1' and `sub1' are a marginally fewer instructions | |
| 704 ;; than `plus' and `minus', so use them when possible. | |
| 705 ((and (null (nthcdr 3 form)) | |
| 706 (eq (nth 2 form) 1)) | |
| 707 (list '1+ (nth 1 form))) ; (+ x 1) --> (1+ x) | |
| 708 ((and (null (nthcdr 3 form)) | |
| 709 (eq (nth 1 form) 1)) | |
| 710 (list '1+ (nth 2 form))) ; (+ 1 x) --> (1+ x) | |
| 711 ((and (null (nthcdr 3 form)) | |
| 712 (eq (nth 2 form) -1)) | |
| 713 (list '1- (nth 1 form))) ; (+ x -1) --> (1- x) | |
| 714 ((and (null (nthcdr 3 form)) | |
| 715 (eq (nth 1 form) -1)) | |
| 716 (list '1- (nth 2 form))) ; (+ -1 x) --> (1- x) | |
| 717 | |
| 718 ;;; It is not safe to delete the function entirely | |
| 719 ;;; (actually, it would be safe if we know the sole arg | |
| 720 ;;; is not a marker). | |
| 721 ;; ((null (cdr (cdr form))) (nth 1 form)) | |
| 722 (t form))) | |
| 723 | |
| 724 (defun byte-optimize-minus (form) | |
| 725 ;; Put constants at the end, except the last constant. | |
| 726 (setq form (byte-optimize-delay-constants-math form 2 '+)) | |
| 727 ;; Now only first and last element can be a number. | |
| 728 (let ((last (car (reverse (nthcdr 3 form))))) | |
| 729 (cond ((eq 0 last) | |
| 730 ;; (- x y ... 0) --> (- x y ...) | |
| 731 (setq form (copy-sequence form)) | |
| 732 (setcdr (cdr (cdr form)) (delq 0 (nthcdr 3 form)))) | |
| 733 ;; If form is (- CONST foo... CONST), merge first and last. | |
| 734 ((and (numberp (nth 1 form)) | |
| 735 (numberp last)) | |
| 736 (setq form (nconc (list '- (- (nth 1 form) last) (nth 2 form)) | |
| 737 (delq last (copy-sequence (nthcdr 3 form)))))))) | |
| 738 (setq form | |
| 739 ;;; It is not safe to delete the function entirely | |
| 740 ;;; (actually, it would be safe if we know the sole arg | |
| 741 ;;; is not a marker). | |
| 742 ;;; (if (eq (nth 2 form) 0) | |
| 743 ;;; (nth 1 form) ; (- x 0) --> x | |
| 744 (byte-optimize-predicate | |
| 745 (if (and (null (cdr (cdr (cdr form)))) | |
| 746 (eq (nth 1 form) 0)) ; (- 0 x) --> (- x) | |
| 747 (cons (car form) (cdr (cdr form))) | |
| 748 form)) | |
| 749 ;;; ) | |
| 750 ) | |
| 751 | |
| 752 ;; `add1' and `sub1' are a marginally fewer instructions than `plus' | |
| 753 ;; and `minus', so use them when possible. | |
| 754 (cond ((and (null (nthcdr 3 form)) | |
| 755 (eq (nth 2 form) 1)) | |
| 756 (list '1- (nth 1 form))) ; (- x 1) --> (1- x) | |
| 757 ((and (null (nthcdr 3 form)) | |
| 758 (eq (nth 2 form) -1)) | |
| 759 (list '1+ (nth 1 form))) ; (- x -1) --> (1+ x) | |
| 760 (t | |
| 761 form)) | |
| 762 ) | |
| 763 | |
| 764 (defun byte-optimize-multiply (form) | |
| 765 (setq form (byte-optimize-delay-constants-math form 1 '*)) | |
| 766 ;; If there is a constant in FORM, it is now the last element. | |
| 767 (cond ((null (cdr form)) 1) | |
| 768 ;;; It is not safe to delete the function entirely | |
| 769 ;;; (actually, it would be safe if we know the sole arg | |
| 770 ;;; is not a marker or if it appears in other arithmetic). | |
| 771 ;;; ((null (cdr (cdr form))) (nth 1 form)) | |
| 772 ((let ((last (car (reverse form)))) | |
| 773 (cond ((eq 0 last) (cons 'progn (cdr form))) | |
| 774 ((eq 1 last) (delq 1 (copy-sequence form))) | |
| 775 ((eq -1 last) (list '- (delq -1 (copy-sequence form)))) | |
| 776 ((and (eq 2 last) | |
| 777 (memq t (mapcar 'symbolp (cdr form)))) | |
| 778 (prog1 (setq form (delq 2 (copy-sequence form))) | |
| 779 (while (not (symbolp (car (setq form (cdr form)))))) | |
| 780 (setcar form (list '+ (car form) (car form))))) | |
| 781 (form)))))) | |
| 782 | |
| 783 (defsubst byte-compile-butlast (form) | |
| 784 (nreverse (cdr (reverse form)))) | |
| 785 | |
| 786 (defun byte-optimize-divide (form) | |
| 787 (setq form (byte-optimize-delay-constants-math form 2 '*)) | |
| 788 (let ((last (car (reverse (cdr (cdr form)))))) | |
| 789 (if (numberp last) | |
| 790 (cond ((= (length form) 3) | |
| 791 (if (and (numberp (nth 1 form)) | |
| 792 (not (zerop last)) | |
| 793 (condition-case nil | |
| 794 (/ (nth 1 form) last) | |
| 795 (error nil))) | |
| 796 (setq form (list 'progn (/ (nth 1 form) last))))) | |
| 797 ((= last 1) | |
| 798 (setq form (byte-compile-butlast form))) | |
| 799 ((numberp (nth 1 form)) | |
| 800 (setq form (cons (car form) | |
| 801 (cons (/ (nth 1 form) last) | |
| 802 (byte-compile-butlast (cdr (cdr form))))) | |
| 803 last nil)))) | |
| 804 (cond | |
| 805 ;;; ((null (cdr (cdr form))) | |
| 806 ;;; (nth 1 form)) | |
| 807 ((eq (nth 1 form) 0) | |
| 808 (append '(progn) (cdr (cdr form)) '(0))) | |
| 809 ((eq last -1) | |
| 810 (list '- (if (nthcdr 3 form) | |
| 811 (byte-compile-butlast form) | |
| 812 (nth 1 form)))) | |
| 813 (form)))) | |
| 814 | |
| 815 (defun byte-optimize-logmumble (form) | |
| 816 (setq form (byte-optimize-delay-constants-math form 1 (car form))) | |
| 817 (byte-optimize-predicate | |
| 818 (cond ((memq 0 form) | |
| 819 (setq form (if (eq (car form) 'logand) | |
| 820 (cons 'progn (cdr form)) | |
| 821 (delq 0 (copy-sequence form))))) | |
| 822 ((and (eq (car-safe form) 'logior) | |
| 823 (memq -1 form)) | |
| 824 (cons 'progn (cdr form))) | |
| 825 (form)))) | |
| 826 | |
| 827 | |
| 828 (defun byte-optimize-binary-predicate (form) | |
| 829 (if (byte-compile-constp (nth 1 form)) | |
| 830 (if (byte-compile-constp (nth 2 form)) | |
| 831 (condition-case () | |
| 832 (list 'quote (eval form)) | |
| 833 (error form)) | |
| 834 ;; This can enable some lapcode optimizations. | |
| 835 (list (car form) (nth 2 form) (nth 1 form))) | |
| 836 form)) | |
| 837 | |
| 838 (defun byte-optimize-predicate (form) | |
| 839 (let ((ok t) | |
| 840 (rest (cdr form))) | |
| 841 (while (and rest ok) | |
| 842 (setq ok (byte-compile-constp (car rest)) | |
| 843 rest (cdr rest))) | |
| 844 (if ok | |
| 845 (condition-case () | |
| 846 (list 'quote (eval form)) | |
| 847 (error form)) | |
| 848 form))) | |
| 849 | |
| 850 (defun byte-optimize-identity (form) | |
| 851 (if (and (cdr form) (null (cdr (cdr form)))) | |
| 852 (nth 1 form) | |
| 853 (byte-compile-warn "identity called with %d arg%s, but requires 1" | |
| 854 (length (cdr form)) | |
| 855 (if (= 1 (length (cdr form))) "" "s")) | |
| 856 form)) | |
| 857 | |
| 858 (put 'identity 'byte-optimizer 'byte-optimize-identity) | |
| 859 | |
| 860 (put '+ 'byte-optimizer 'byte-optimize-plus) | |
| 861 (put '* 'byte-optimizer 'byte-optimize-multiply) | |
| 862 (put '- 'byte-optimizer 'byte-optimize-minus) | |
| 863 (put '/ 'byte-optimizer 'byte-optimize-divide) | |
| 864 (put 'max 'byte-optimizer 'byte-optimize-associative-math) | |
| 865 (put 'min 'byte-optimizer 'byte-optimize-associative-math) | |
| 866 | |
| 867 (put '= 'byte-optimizer 'byte-optimize-binary-predicate) | |
| 868 (put 'eq 'byte-optimizer 'byte-optimize-binary-predicate) | |
| 869 (put 'eql 'byte-optimizer 'byte-optimize-binary-predicate) | |
| 870 (put 'equal 'byte-optimizer 'byte-optimize-binary-predicate) | |
| 871 (put 'string= 'byte-optimizer 'byte-optimize-binary-predicate) | |
| 872 (put 'string-equal 'byte-optimizer 'byte-optimize-binary-predicate) | |
| 873 | |
| 874 (put '< 'byte-optimizer 'byte-optimize-predicate) | |
| 875 (put '> 'byte-optimizer 'byte-optimize-predicate) | |
| 876 (put '<= 'byte-optimizer 'byte-optimize-predicate) | |
| 877 (put '>= 'byte-optimizer 'byte-optimize-predicate) | |
| 878 (put '1+ 'byte-optimizer 'byte-optimize-predicate) | |
| 879 (put '1- 'byte-optimizer 'byte-optimize-predicate) | |
| 880 (put 'not 'byte-optimizer 'byte-optimize-predicate) | |
| 881 (put 'null 'byte-optimizer 'byte-optimize-predicate) | |
| 882 (put 'memq 'byte-optimizer 'byte-optimize-predicate) | |
| 883 (put 'consp 'byte-optimizer 'byte-optimize-predicate) | |
| 884 (put 'listp 'byte-optimizer 'byte-optimize-predicate) | |
| 885 (put 'symbolp 'byte-optimizer 'byte-optimize-predicate) | |
| 886 (put 'stringp 'byte-optimizer 'byte-optimize-predicate) | |
| 887 (put 'string< 'byte-optimizer 'byte-optimize-predicate) | |
| 888 (put 'string-lessp 'byte-optimizer 'byte-optimize-predicate) | |
| 889 | |
| 890 (put 'logand 'byte-optimizer 'byte-optimize-logmumble) | |
| 891 (put 'logior 'byte-optimizer 'byte-optimize-logmumble) | |
| 892 (put 'logxor 'byte-optimizer 'byte-optimize-logmumble) | |
| 893 (put 'lognot 'byte-optimizer 'byte-optimize-predicate) | |
| 894 | |
| 895 (put 'car 'byte-optimizer 'byte-optimize-predicate) | |
| 896 (put 'cdr 'byte-optimizer 'byte-optimize-predicate) | |
| 897 (put 'car-safe 'byte-optimizer 'byte-optimize-predicate) | |
| 898 (put 'cdr-safe 'byte-optimizer 'byte-optimize-predicate) | |
| 899 | |
| 900 | |
| 901 ;; I'm not convinced that this is necessary. Doesn't the optimizer loop | |
| 902 ;; take care of this? - Jamie | |
| 903 ;; I think this may some times be necessary to reduce ie (quote 5) to 5, | |
| 904 ;; so arithmetic optimizers recognize the numeric constant. - Hallvard | |
| 905 (put 'quote 'byte-optimizer 'byte-optimize-quote) | |
| 906 (defun byte-optimize-quote (form) | |
| 907 (if (or (consp (nth 1 form)) | |
| 908 (and (symbolp (nth 1 form)) | |
| 909 ;; XEmacs addition: | |
| 910 (not (keywordp (nth 1 form))) | |
| 911 (not (memq (nth 1 form) '(nil t))))) | |
| 912 form | |
| 913 (nth 1 form))) | |
| 914 | |
| 915 (defun byte-optimize-zerop (form) | |
| 916 (cond ((numberp (nth 1 form)) | |
| 917 (eval form)) | |
| 918 (byte-compile-delete-errors | |
| 919 (list '= (nth 1 form) 0)) | |
| 920 (form))) | |
| 921 | |
| 922 (put 'zerop 'byte-optimizer 'byte-optimize-zerop) | |
| 923 | |
| 924 (defun byte-optimize-and (form) | |
| 925 ;; Simplify if less than 2 args. | |
| 926 ;; if there is a literal nil in the args to `and', throw it and following | |
| 927 ;; forms away, and surround the `and' with (progn ... nil). | |
| 928 (cond ((null (cdr form))) | |
| 929 ((memq nil form) | |
| 930 (list 'progn | |
| 931 (byte-optimize-and | |
| 932 (prog1 (setq form (copy-sequence form)) | |
| 933 (while (nth 1 form) | |
| 934 (setq form (cdr form))) | |
| 935 (setcdr form nil))) | |
| 936 nil)) | |
| 937 ((null (cdr (cdr form))) | |
| 938 (nth 1 form)) | |
| 939 ((byte-optimize-predicate form)))) | |
| 940 | |
| 941 (defun byte-optimize-or (form) | |
| 942 ;; Throw away nil's, and simplify if less than 2 args. | |
| 943 ;; If there is a literal non-nil constant in the args to `or', throw away all | |
| 944 ;; following forms. | |
| 945 (if (memq nil form) | |
| 946 (setq form (delq nil (copy-sequence form)))) | |
| 947 (let ((rest form)) | |
| 948 (while (cdr (setq rest (cdr rest))) | |
| 949 (if (byte-compile-trueconstp (car rest)) | |
| 950 (setq form (copy-sequence form) | |
| 951 rest (setcdr (memq (car rest) form) nil)))) | |
| 952 (if (cdr (cdr form)) | |
| 953 (byte-optimize-predicate form) | |
| 954 (nth 1 form)))) | |
| 955 | |
| 956 (defun byte-optimize-cond (form) | |
| 957 ;; if any clauses have a literal nil as their test, throw them away. | |
| 958 ;; if any clause has a literal non-nil constant as its test, throw | |
| 959 ;; away all following clauses. | |
| 960 (let (rest) | |
| 961 ;; This must be first, to reduce (cond (t ...) (nil)) to (progn t ...) | |
| 962 (while (setq rest (assq nil (cdr form))) | |
| 963 (setq form (delq rest (copy-sequence form)))) | |
| 964 (if (memq nil (cdr form)) | |
| 965 (setq form (delq nil (copy-sequence form)))) | |
| 966 (setq rest form) | |
| 967 (while (setq rest (cdr rest)) | |
| 968 (cond ((byte-compile-trueconstp (car-safe (car rest))) | |
| 969 (cond ((eq rest (cdr form)) | |
| 970 (setq form | |
| 971 (if (cdr (car rest)) | |
| 972 (if (cdr (cdr (car rest))) | |
| 973 (cons 'progn (cdr (car rest))) | |
| 974 (nth 1 (car rest))) | |
| 975 (car (car rest))))) | |
| 976 ((cdr rest) | |
| 977 (setq form (copy-sequence form)) | |
| 978 (setcdr (memq (car rest) form) nil))) | |
| 979 (setq rest nil))))) | |
| 980 ;; | |
| 981 ;; Turn (cond (( <x> )) ... ) into (or <x> (cond ... )) | |
| 982 (if (eq 'cond (car-safe form)) | |
| 983 (let ((clauses (cdr form))) | |
| 984 (if (and (consp (car clauses)) | |
| 985 (null (cdr (car clauses)))) | |
| 986 (list 'or (car (car clauses)) | |
| 987 (byte-optimize-cond | |
| 988 (cons (car form) (cdr (cdr form))))) | |
| 989 form)) | |
| 990 form)) | |
| 991 | |
| 992 (defun byte-optimize-if (form) | |
| 993 ;; (if <true-constant> <then> <else...>) ==> <then> | |
| 994 ;; (if <false-constant> <then> <else...>) ==> (progn <else...>) | |
| 995 ;; (if <test> nil <else...>) ==> (if (not <test>) (progn <else...>)) | |
| 996 ;; (if <test> <then> nil) ==> (if <test> <then>) | |
| 997 (let ((clause (nth 1 form))) | |
| 998 (cond ((byte-compile-trueconstp clause) | |
| 999 (nth 2 form)) | |
| 1000 ((null clause) | |
| 1001 (if (nthcdr 4 form) | |
| 1002 (cons 'progn (nthcdr 3 form)) | |
| 1003 (nth 3 form))) | |
| 1004 ((nth 2 form) | |
| 1005 (if (equal '(nil) (nthcdr 3 form)) | |
| 1006 (list 'if clause (nth 2 form)) | |
| 1007 form)) | |
| 1008 ((or (nth 3 form) (nthcdr 4 form)) | |
| 1009 (list 'if | |
| 1010 ;; Don't make a double negative; | |
| 1011 ;; instead, take away the one that is there. | |
| 1012 (if (and (consp clause) (memq (car clause) '(not null)) | |
| 1013 (= (length clause) 2)) ; (not xxxx) or (not (xxxx)) | |
| 1014 (nth 1 clause) | |
| 1015 (list 'not clause)) | |
| 1016 (if (nthcdr 4 form) | |
| 1017 (cons 'progn (nthcdr 3 form)) | |
| 1018 (nth 3 form)))) | |
| 1019 (t | |
| 1020 (list 'progn clause nil))))) | |
| 1021 | |
| 1022 (defun byte-optimize-while (form) | |
| 1023 (if (nth 1 form) | |
| 1024 form)) | |
| 1025 | |
| 1026 (put 'and 'byte-optimizer 'byte-optimize-and) | |
| 1027 (put 'or 'byte-optimizer 'byte-optimize-or) | |
| 1028 (put 'cond 'byte-optimizer 'byte-optimize-cond) | |
| 1029 (put 'if 'byte-optimizer 'byte-optimize-if) | |
| 1030 (put 'while 'byte-optimizer 'byte-optimize-while) | |
| 1031 | |
| 1032 ;; byte-compile-negation-optimizer lives in bytecomp.el | |
| 1033 (put '/= 'byte-optimizer 'byte-compile-negation-optimizer) | |
| 1034 (put 'atom 'byte-optimizer 'byte-compile-negation-optimizer) | |
| 1035 (put 'nlistp 'byte-optimizer 'byte-compile-negation-optimizer) | |
| 1036 | |
| 1037 | |
| 1038 (defun byte-optimize-funcall (form) | |
| 1039 ;; (funcall '(lambda ...) ...) ==> ((lambda ...) ...) | |
| 1040 ;; (funcall 'foo ...) ==> (foo ...) | |
| 1041 (let ((fn (nth 1 form))) | |
| 1042 (if (memq (car-safe fn) '(quote function)) | |
| 1043 (cons (nth 1 fn) (cdr (cdr form))) | |
| 1044 form))) | |
| 1045 | |
| 1046 (defun byte-optimize-apply (form) | |
| 1047 ;; If the last arg is a literal constant, turn this into a funcall. | |
| 1048 ;; The funcall optimizer can then transform (funcall 'foo ...) -> (foo ...). | |
| 1049 (let ((fn (nth 1 form)) | |
| 1050 (last (nth (1- (length form)) form))) ; I think this really is fastest | |
| 1051 (or (if (or (null last) | |
| 1052 (eq (car-safe last) 'quote)) | |
| 1053 (if (listp (nth 1 last)) | |
| 1054 (let ((butlast (nreverse (cdr (reverse (cdr (cdr form))))))) | |
| 1055 (nconc (list 'funcall fn) butlast | |
| 1056 (mapcar '(lambda (x) (list 'quote x)) (nth 1 last)))) | |
| 1057 (byte-compile-warn | |
| 1058 "last arg to apply can't be a literal atom: %s" | |
| 1059 (prin1-to-string last)) | |
| 1060 nil)) | |
| 1061 form))) | |
| 1062 | |
| 1063 (put 'funcall 'byte-optimizer 'byte-optimize-funcall) | |
| 1064 (put 'apply 'byte-optimizer 'byte-optimize-apply) | |
| 1065 | |
| 1066 | |
| 1067 (put 'let 'byte-optimizer 'byte-optimize-letX) | |
| 1068 (put 'let* 'byte-optimizer 'byte-optimize-letX) | |
| 1069 (defun byte-optimize-letX (form) | |
| 1070 (cond ((null (nth 1 form)) | |
| 1071 ;; No bindings | |
| 1072 (cons 'progn (cdr (cdr form)))) | |
| 1073 ((or (nth 2 form) (nthcdr 3 form)) | |
| 1074 form) | |
| 1075 ;; The body is nil | |
| 1076 ((eq (car form) 'let) | |
| 1077 (append '(progn) (mapcar 'car-safe (mapcar 'cdr-safe (nth 1 form))) | |
| 1078 '(nil))) | |
| 1079 (t | |
| 1080 (let ((binds (reverse (nth 1 form)))) | |
| 1081 (list 'let* (reverse (cdr binds)) (nth 1 (car binds)) nil))))) | |
| 1082 | |
| 1083 | |
| 1084 (put 'nth 'byte-optimizer 'byte-optimize-nth) | |
| 1085 (defun byte-optimize-nth (form) | |
| 1086 (if (and (= (safe-length form) 3) (memq (nth 1 form) '(0 1))) | |
| 1087 (list 'car (if (zerop (nth 1 form)) | |
| 1088 (nth 2 form) | |
| 1089 (list 'cdr (nth 2 form)))) | |
| 1090 (byte-optimize-predicate form))) | |
| 1091 | |
| 1092 (put 'nthcdr 'byte-optimizer 'byte-optimize-nthcdr) | |
| 1093 (defun byte-optimize-nthcdr (form) | |
| 1094 (if (and (= (safe-length form) 3) (not (memq (nth 1 form) '(0 1 2)))) | |
| 1095 (byte-optimize-predicate form) | |
| 1096 (let ((count (nth 1 form))) | |
| 1097 (setq form (nth 2 form)) | |
| 1098 (while (>= (setq count (1- count)) 0) | |
| 1099 (setq form (list 'cdr form))) | |
| 1100 form))) | |
| 1101 | |
| 1102 ;;; enumerating those functions which need not be called if the returned | |
| 1103 ;;; value is not used. That is, something like | |
| 1104 ;;; (progn (list (something-with-side-effects) (yow)) | |
| 1105 ;;; (foo)) | |
| 1106 ;;; may safely be turned into | |
| 1107 ;;; (progn (progn (something-with-side-effects) (yow)) | |
| 1108 ;;; (foo)) | |
| 1109 ;;; Further optimizations will turn (progn (list 1 2 3) 'foo) into 'foo. | |
| 1110 | |
| 1111 ;;; I wonder if I missed any :-\) | |
| 1112 (let ((side-effect-free-fns | |
| 1113 '(% * + - / /= 1+ 1- < <= = > >= abs acos append aref ash asin atan | |
| 1114 assoc assq | |
| 1115 boundp buffer-file-name buffer-local-variables buffer-modified-p | |
| 1116 buffer-substring | |
| 1117 capitalize car-less-than-car car cdr ceiling concat | |
| 1118 ;; coordinates-in-window-p not in XEmacs | |
| 1119 copy-marker cos count-lines | |
| 1120 default-boundp default-value documentation downcase | |
| 1121 elt exp expt fboundp featurep | |
| 1122 file-directory-p file-exists-p file-locked-p file-name-absolute-p | |
| 1123 file-newer-than-file-p file-readable-p file-symlink-p file-writable-p | |
| 1124 float floor format | |
| 1125 get get-buffer get-buffer-window getenv get-file-buffer | |
| 1126 int-to-string | |
| 1127 length log log10 logand logb logior lognot logxor lsh | |
| 1128 marker-buffer max member memq min mod | |
| 1129 next-window nth nthcdr number-to-string | |
| 1130 parse-colon-path previous-window | |
| 1131 radians-to-degrees rassq regexp-quote reverse round | |
| 1132 sin sqrt string< string= string-equal string-lessp string-to-char | |
| 1133 string-to-int string-to-number substring symbol-plist | |
| 1134 tan upcase user-variable-p vconcat | |
| 1135 ;; XEmacs change: window-edges -> window-pixel-edges | |
| 1136 window-buffer window-dedicated-p window-pixel-edges window-height | |
| 1137 window-hscroll window-minibuffer-p window-width | |
| 1138 zerop)) | |
| 1139 (side-effect-and-error-free-fns | |
| 1140 '(arrayp atom | |
| 1141 bobp bolp buffer-end buffer-list buffer-size buffer-string bufferp | |
| 1142 car-safe case-table-p cdr-safe char-or-string-p char-table-p | |
| 1143 characterp commandp cons | |
| 1144 consolep console-live-p consp | |
| 1145 current-buffer | |
| 1146 ;; XEmacs: extent functions, frame-live-p, various other stuff | |
| 1147 devicep device-live-p | |
| 1148 dot dot-marker eobp eolp eq eql equal eventp extentp | |
| 1149 extent-live-p floatp framep frame-live-p | |
| 1150 get-largest-window get-lru-window | |
| 1151 identity ignore integerp integer-or-marker-p interactive-p | |
| 1152 invocation-directory invocation-name | |
| 1153 ;; keymapp may autoload in XEmacs, so not on this list! | |
| 1154 list listp | |
| 1155 make-marker mark mark-marker markerp memory-limit minibuffer-window | |
| 1156 ;; mouse-movement-p not in XEmacs | |
| 1157 natnump nlistp not null number-or-marker-p numberp | |
| 1158 one-window-p ;; overlayp not in XEmacs | |
| 1159 point point-marker point-min point-max processp | |
| 1160 range-table-p | |
| 1161 selected-window sequencep stringp subrp symbolp syntax-table-p | |
| 1162 user-full-name user-login-name user-original-login-name | |
| 1163 user-real-login-name user-real-uid user-uid | |
| 1164 vector vectorp | |
| 1165 window-configuration-p window-live-p windowp))) | |
| 1166 (while side-effect-free-fns | |
| 1167 (put (car side-effect-free-fns) 'side-effect-free t) | |
| 1168 (setq side-effect-free-fns (cdr side-effect-free-fns))) | |
| 1169 (while side-effect-and-error-free-fns | |
| 1170 (put (car side-effect-and-error-free-fns) 'side-effect-free 'error-free) | |
| 1171 (setq side-effect-and-error-free-fns (cdr side-effect-and-error-free-fns))) | |
| 1172 nil) | |
| 1173 | |
| 1174 | |
| 1175 (defun byte-compile-splice-in-already-compiled-code (form) | |
| 1176 ;; form is (byte-code "..." [...] n) | |
| 1177 (if (not (memq byte-optimize '(t lap))) | |
| 1178 (byte-compile-normal-call form) | |
| 1179 (byte-inline-lapcode | |
| 1180 (byte-decompile-bytecode-1 (nth 1 form) (nth 2 form) t)) | |
| 1181 (setq byte-compile-maxdepth (max (+ byte-compile-depth (nth 3 form)) | |
| 1182 byte-compile-maxdepth)) | |
| 1183 (setq byte-compile-depth (1+ byte-compile-depth)))) | |
| 1184 | |
| 1185 (put 'byte-code 'byte-compile 'byte-compile-splice-in-already-compiled-code) | |
| 1186 | |
| 1187 | |
| 1188 (defconst byte-constref-ops | |
| 1189 '(byte-constant byte-constant2 byte-varref byte-varset byte-varbind)) | |
| 1190 | |
| 1191 ;;; This function extracts the bitfields from variable-length opcodes. | |
| 1192 ;;; Originally defined in disass.el (which no longer uses it.) | |
| 1193 | |
| 1194 (defun disassemble-offset () | |
| 1195 "Don't call this!" | |
| 1196 ;; fetch and return the offset for the current opcode. | |
| 1197 ;; return NIL if this opcode has no offset | |
| 1198 ;; OP, PTR and BYTES are used and set dynamically | |
| 1199 (defvar op) | |
| 1200 (defvar ptr) | |
| 1201 (defvar bytes) | |
| 1202 (cond ((< op byte-nth) | |
| 1203 (let ((tem (logand op 7))) | |
| 1204 (setq op (logand op 248)) | |
| 1205 (cond ((eq tem 6) | |
| 1206 (setq ptr (1+ ptr)) ;offset in next byte | |
| 1207 ;; char-to-int to avoid downstream problems | |
| 1208 ;; caused by chars appearing where ints are | |
| 1209 ;; expected. In bytecode the bytes in the | |
| 1210 ;; opcode string are always interpreted as ints. | |
| 1211 (char-to-int (aref bytes ptr))) | |
| 1212 ((eq tem 7) | |
| 1213 (setq ptr (1+ ptr)) ;offset in next 2 bytes | |
| 1214 (+ (aref bytes ptr) | |
| 1215 (progn (setq ptr (1+ ptr)) | |
| 1216 (lsh (aref bytes ptr) 8)))) | |
| 1217 (t tem)))) ;offset was in opcode | |
| 1218 ((>= op byte-constant) | |
| 1219 (prog1 (- op byte-constant) ;offset in opcode | |
| 1220 (setq op byte-constant))) | |
| 1221 ((and (>= op byte-constant2) | |
| 1222 (<= op byte-goto-if-not-nil-else-pop)) | |
| 1223 (setq ptr (1+ ptr)) ;offset in next 2 bytes | |
| 1224 (+ (aref bytes ptr) | |
| 1225 (progn (setq ptr (1+ ptr)) | |
| 1226 (lsh (aref bytes ptr) 8)))) | |
| 1227 ;; XEmacs: this code was here before. FSF's first comparison | |
| 1228 ;; is (>= op byte-listN). It appears that the rel-goto stuff | |
| 1229 ;; does not exist in FSF 19.30. It doesn't exist in 19.28 | |
| 1230 ;; either, so I'm going to assume that this is an improvement | |
| 1231 ;; on our part and leave it in. --ben | |
| 1232 ((and (>= op byte-rel-goto) | |
| 1233 (<= op byte-insertN)) | |
| 1234 (setq ptr (1+ ptr)) ;offset in next byte | |
| 1235 ;; Use char-to-int to avoid downstream problems caused by | |
| 1236 ;; chars appearing where ints are expected. In bytecode | |
| 1237 ;; the bytes in the opcode string are always interpreted as | |
| 1238 ;; ints. | |
| 1239 (char-to-int (aref bytes ptr))))) | |
| 1240 | |
| 1241 | |
| 1242 ;;; This de-compiler is used for inline expansion of compiled functions, | |
| 1243 ;;; and by the disassembler. | |
| 1244 ;;; | |
| 1245 ;;; This list contains numbers, which are pc values, | |
| 1246 ;;; before each instruction. | |
| 1247 (defun byte-decompile-bytecode (bytes constvec) | |
| 1248 "Turns BYTECODE into lapcode, referring to CONSTVEC." | |
| 1249 (let ((byte-compile-constants nil) | |
| 1250 (byte-compile-variables nil) | |
| 1251 (byte-compile-tag-number 0)) | |
| 1252 (byte-decompile-bytecode-1 bytes constvec))) | |
| 1253 | |
| 1254 ;; As byte-decompile-bytecode, but updates | |
| 1255 ;; byte-compile-{constants, variables, tag-number}. | |
| 1256 ;; If MAKE-SPLICEABLE is true, then `return' opcodes are replaced | |
| 1257 ;; with `goto's destined for the end of the code. | |
| 1258 ;; That is for use by the compiler. | |
| 1259 ;; If MAKE-SPLICEABLE is nil, we are being called for the disassembler. | |
| 1260 ;; In that case, we put a pc value into the list | |
| 1261 ;; before each insn (or its label). | |
| 1262 (defun byte-decompile-bytecode-1 (bytes constvec &optional make-spliceable) | |
| 1263 (let ((length (length bytes)) | |
| 1264 (ptr 0) optr tags op offset | |
| 1265 ;; tag unused | |
| 1266 lap tmp | |
| 1267 endtag | |
| 1268 ;; (retcount 0) unused | |
| 1269 ) | |
| 1270 (while (not (= ptr length)) | |
| 1271 (or make-spliceable | |
| 1272 (setq lap (cons ptr lap))) | |
| 1273 (setq op (aref bytes ptr) | |
| 1274 optr ptr | |
| 1275 offset (disassemble-offset)) ; this does dynamic-scope magic | |
| 1276 (setq op (aref byte-code-vector op)) | |
| 1277 ;; XEmacs: the next line in FSF 19.30 reads | |
| 1278 ;; (cond ((memq op byte-goto-ops) | |
| 1279 ;; see the comment above about byte-rel-goto in XEmacs. | |
| 1280 (cond ((or (memq op byte-goto-ops) | |
| 1281 (cond ((memq op byte-rel-goto-ops) | |
| 1282 (setq op (aref byte-code-vector | |
| 1283 (- (symbol-value op) | |
| 1284 (- byte-rel-goto byte-goto)))) | |
| 1285 (setq offset (+ ptr (- offset 127))) | |
| 1286 t))) | |
| 1287 ;; it's a pc | |
| 1288 (setq offset | |
| 1289 (cdr (or (assq offset tags) | |
| 1290 (car (setq tags | |
| 1291 (cons (cons offset | |
| 1292 (byte-compile-make-tag)) | |
| 1293 tags))))))) | |
| 1294 ((cond ((eq op 'byte-constant2) (setq op 'byte-constant) t) | |
| 1295 ((memq op byte-constref-ops))) | |
| 1296 (setq tmp (aref constvec offset) | |
| 1297 offset (if (eq op 'byte-constant) | |
| 1298 (byte-compile-get-constant tmp) | |
| 1299 (or (assq tmp byte-compile-variables) | |
| 1300 (car (setq byte-compile-variables | |
| 1301 (cons (list tmp) | |
| 1302 byte-compile-variables))))))) | |
| 1303 ((and make-spliceable | |
| 1304 (eq op 'byte-return)) | |
| 1305 (if (= ptr (1- length)) | |
| 1306 (setq op nil) | |
| 1307 (setq offset (or endtag (setq endtag (byte-compile-make-tag))) | |
| 1308 op 'byte-goto)))) | |
| 1309 ;; lap = ( [ (pc . (op . arg)) ]* ) | |
| 1310 (setq lap (cons (cons optr (cons op (or offset 0))) | |
| 1311 lap)) | |
| 1312 (setq ptr (1+ ptr))) | |
| 1313 ;; take off the dummy nil op that we replaced a trailing "return" with. | |
| 1314 (let ((rest lap)) | |
| 1315 (while rest | |
| 1316 (cond ((numberp (car rest))) | |
| 1317 ((setq tmp (assq (car (car rest)) tags)) | |
| 1318 ;; this addr is jumped to | |
| 1319 (setcdr rest (cons (cons nil (cdr tmp)) | |
| 1320 (cdr rest))) | |
| 1321 (setq tags (delq tmp tags)) | |
| 1322 (setq rest (cdr rest)))) | |
| 1323 (setq rest (cdr rest)))) | |
| 1324 (if tags (error "optimizer error: missed tags %s" tags)) | |
| 1325 (if (null (car (cdr (car lap)))) | |
| 1326 (setq lap (cdr lap))) | |
| 1327 (if endtag | |
| 1328 (setq lap (cons (cons nil endtag) lap))) | |
| 1329 ;; remove addrs, lap = ( [ (op . arg) | (TAG tagno) ]* ) | |
| 1330 (mapcar (function (lambda (elt) | |
| 1331 (if (numberp elt) | |
| 1332 elt | |
| 1333 (cdr elt)))) | |
| 1334 (nreverse lap)))) | |
| 1335 | |
| 1336 | |
| 1337 ;;; peephole optimizer | |
| 1338 | |
| 1339 (defconst byte-tagref-ops (cons 'TAG byte-goto-ops)) | |
| 1340 | |
| 1341 (defconst byte-conditional-ops | |
| 1342 '(byte-goto-if-nil byte-goto-if-not-nil byte-goto-if-nil-else-pop | |
| 1343 byte-goto-if-not-nil-else-pop)) | |
| 1344 | |
| 1345 (defconst byte-after-unbind-ops | |
| 1346 '(byte-constant byte-dup | |
| 1347 byte-symbolp byte-consp byte-stringp byte-listp byte-numberp byte-integerp | |
| 1348 byte-eq byte-equal byte-not | |
| 1349 byte-cons byte-list1 byte-list2 ; byte-list3 byte-list4 | |
| 1350 byte-interactive-p) | |
| 1351 ;; How about other side-effect-free-ops? Is it safe to move an | |
| 1352 ;; error invocation (such as from nth) out of an unwind-protect? | |
| 1353 "Byte-codes that can be moved past an unbind.") | |
| 1354 | |
| 1355 (defconst byte-compile-side-effect-and-error-free-ops | |
| 1356 '(byte-constant byte-dup byte-symbolp byte-consp byte-stringp byte-listp | |
| 1357 byte-integerp byte-numberp byte-eq byte-equal byte-not byte-car-safe | |
| 1358 byte-cdr-safe byte-cons byte-list1 byte-list2 byte-point byte-point-max | |
| 1359 byte-point-min byte-following-char byte-preceding-char | |
| 1360 byte-current-column byte-eolp byte-eobp byte-bolp byte-bobp | |
| 1361 byte-current-buffer byte-interactive-p)) | |
| 1362 | |
| 1363 (defconst byte-compile-side-effect-free-ops | |
| 1364 (nconc | |
| 1365 '(byte-varref byte-nth byte-memq byte-car byte-cdr byte-length byte-aref | |
| 1366 byte-symbol-value byte-get byte-concat2 byte-concat3 byte-sub1 byte-add1 | |
| 1367 byte-eqlsign byte-gtr byte-lss byte-leq byte-geq byte-diff byte-negate | |
| 1368 byte-plus byte-max byte-min byte-mult byte-char-after byte-char-syntax | |
| 1369 byte-buffer-substring byte-string= byte-string< byte-nthcdr byte-elt | |
| 1370 byte-member byte-assq byte-quo byte-rem) | |
| 1371 byte-compile-side-effect-and-error-free-ops)) | |
| 1372 | |
| 1373 ;;; This piece of shit is because of the way DEFVAR_BOOL() variables work. | |
| 1374 ;;; Consider the code | |
| 1375 ;;; | |
| 1376 ;;; (defun foo (flag) | |
| 1377 ;;; (let ((old-pop-ups pop-up-windows) | |
| 1378 ;;; (pop-up-windows flag)) | |
| 1379 ;;; (cond ((not (eq pop-up-windows old-pop-ups)) | |
| 1380 ;;; (setq old-pop-ups pop-up-windows) | |
| 1381 ;;; ...)))) | |
| 1382 ;;; | |
| 1383 ;;; Uncompiled, old-pop-ups will always be set to nil or t, even if FLAG is | |
| 1384 ;;; something else. But if we optimize | |
| 1385 ;;; | |
| 1386 ;;; varref flag | |
| 1387 ;;; varbind pop-up-windows | |
| 1388 ;;; varref pop-up-windows | |
| 1389 ;;; not | |
| 1390 ;;; to | |
| 1391 ;;; varref flag | |
| 1392 ;;; dup | |
| 1393 ;;; varbind pop-up-windows | |
| 1394 ;;; not | |
| 1395 ;;; | |
| 1396 ;;; we break the program, because it will appear that pop-up-windows and | |
| 1397 ;;; old-pop-ups are not EQ when really they are. So we have to know what | |
| 1398 ;;; the BOOL variables are, and not perform this optimization on them. | |
| 1399 ;;; | |
| 1400 (defconst byte-boolean-vars | |
| 1401 '(abbrev-all-caps purify-flag find-file-compare-truenames | |
| 1402 find-file-use-truenames find-file-visit-truename | |
| 1403 find-file-existing-other-name byte-metering-on | |
| 1404 zmacs-regions zmacs-region-active-p zmacs-region-stays | |
| 1405 atomic-extent-goto-char-p suppress-early-error-handler | |
| 1406 noninteractive ignore-kernel debug-on-quit debug-on-next-call | |
| 1407 modifier-keys-are-sticky x-allow-sendevents vms-stmlf-recfm | |
| 1408 disable-auto-save-when-buffer-shrinks indent-tabs-mode | |
| 1409 load-in-progress load-warn-when-source-newer load-warn-when-source-only | |
| 1410 load-ignore-elc-files load-force-doc-strings | |
| 1411 fail-on-bucky-bit-character-escapes popup-menu-titles | |
| 1412 menubar-show-keybindings completion-ignore-case | |
| 1413 canna-empty-info canna-through-info canna-underline | |
| 1414 canna-inhibit-hankakukana x-handle-non-fully-specified-fonts | |
| 1415 print-escape-newlines print-readably print-gensym | |
| 1416 delete-exited-processes truncate-partial-width-windows | |
| 1417 visible-bell no-redraw-on-reenter cursor-in-echo-area | |
| 1418 inhibit-warning-display parse-sexp-ignore-comments words-include-escapes | |
| 1419 scroll-on-clipped-lines pop-up-frames pop-up-windows) | |
| 1420 "DEFVAR_BOOL variables. Giving these any non-nil value sets them to t. | |
| 1421 If this does not enumerate all DEFVAR_BOOL variables, the byte-optimizer | |
| 1422 may generate incorrect code.") | |
| 1423 | |
| 1424 (defun byte-optimize-lapcode (lap &optional for-effect) | |
| 1425 "Simple peephole optimizer. LAP is both modified and returned." | |
| 1426 (let (lap0 ;; off0 unused | |
| 1427 lap1 ;; off1 | |
| 1428 lap2 ;; off2 | |
| 1429 (keep-going 'first-time) | |
| 1430 (add-depth 0) | |
| 1431 rest tmp tmp2 tmp3 | |
| 1432 (side-effect-free (if byte-compile-delete-errors | |
| 1433 byte-compile-side-effect-free-ops | |
| 1434 byte-compile-side-effect-and-error-free-ops))) | |
| 1435 (while keep-going | |
| 1436 (or (eq keep-going 'first-time) | |
| 1437 (byte-compile-log-lap " ---- next pass")) | |
| 1438 (setq rest lap | |
| 1439 keep-going nil) | |
| 1440 (while rest | |
| 1441 (setq lap0 (car rest) | |
| 1442 lap1 (nth 1 rest) | |
| 1443 lap2 (nth 2 rest)) | |
| 1444 | |
| 1445 ;; You may notice that sequences like "dup varset discard" are | |
| 1446 ;; optimized but sequences like "dup varset TAG1: discard" are not. | |
| 1447 ;; You may be tempted to change this; resist that temptation. | |
| 1448 (cond ;; | |
| 1449 ;; <side-effect-free> pop --> <deleted> | |
| 1450 ;; ...including: | |
| 1451 ;; const-X pop --> <deleted> | |
| 1452 ;; varref-X pop --> <deleted> | |
| 1453 ;; dup pop --> <deleted> | |
| 1454 ;; | |
| 1455 ((and (eq 'byte-discard (car lap1)) | |
| 1456 (memq (car lap0) side-effect-free)) | |
| 1457 (setq keep-going t) | |
| 1458 (setq tmp (aref byte-stack+-info (symbol-value (car lap0)))) | |
| 1459 (setq rest (cdr rest)) | |
| 1460 (cond ((= tmp 1) | |
| 1461 (byte-compile-log-lap | |
| 1462 " %s discard\t-->\t<deleted>" lap0) | |
| 1463 (setq lap (delq lap0 (delq lap1 lap)))) | |
| 1464 ((= tmp 0) | |
| 1465 (byte-compile-log-lap | |
| 1466 " %s discard\t-->\t<deleted> discard" lap0) | |
| 1467 (setq lap (delq lap0 lap))) | |
| 1468 ((= tmp -1) | |
| 1469 (byte-compile-log-lap | |
| 1470 " %s discard\t-->\tdiscard discard" lap0) | |
| 1471 (setcar lap0 'byte-discard) | |
| 1472 (setcdr lap0 0)) | |
| 1473 ((error "Optimizer error: too much on the stack")))) | |
| 1474 ;; | |
| 1475 ;; goto*-X X: --> X: | |
| 1476 ;; | |
| 1477 ((and (memq (car lap0) byte-goto-ops) | |
| 1478 (eq (cdr lap0) lap1)) | |
| 1479 (cond ((eq (car lap0) 'byte-goto) | |
| 1480 (setq lap (delq lap0 lap)) | |
| 1481 (setq tmp "<deleted>")) | |
| 1482 ((memq (car lap0) byte-goto-always-pop-ops) | |
| 1483 (setcar lap0 (setq tmp 'byte-discard)) | |
| 1484 (setcdr lap0 0)) | |
| 1485 ((error "Depth conflict at tag %d" (nth 2 lap0)))) | |
| 1486 (and (memq byte-optimize-log '(t byte)) | |
| 1487 (byte-compile-log " (goto %s) %s:\t-->\t%s %s:" | |
| 1488 (nth 1 lap1) (nth 1 lap1) | |
| 1489 tmp (nth 1 lap1))) | |
| 1490 (setq keep-going t)) | |
| 1491 ;; | |
| 1492 ;; varset-X varref-X --> dup varset-X | |
| 1493 ;; varbind-X varref-X --> dup varbind-X | |
| 1494 ;; const/dup varset-X varref-X --> const/dup varset-X const/dup | |
| 1495 ;; const/dup varbind-X varref-X --> const/dup varbind-X const/dup | |
| 1496 ;; The latter two can enable other optimizations. | |
| 1497 ;; | |
| 1498 ((and (eq 'byte-varref (car lap2)) | |
| 1499 (eq (cdr lap1) (cdr lap2)) | |
| 1500 (memq (car lap1) '(byte-varset byte-varbind))) | |
| 1501 (if (and (setq tmp (memq (car (cdr lap2)) byte-boolean-vars)) | |
| 1502 (not (eq (car lap0) 'byte-constant))) | |
| 1503 nil | |
| 1504 (setq keep-going t) | |
| 1505 (if (memq (car lap0) '(byte-constant byte-dup)) | |
| 1506 (progn | |
| 1507 (setq tmp (if (or (not tmp) | |
| 1508 (memq (car (cdr lap0)) '(nil t))) | |
| 1509 (cdr lap0) | |
| 1510 (byte-compile-get-constant t))) | |
| 1511 (byte-compile-log-lap " %s %s %s\t-->\t%s %s %s" | |
| 1512 lap0 lap1 lap2 lap0 lap1 | |
| 1513 (cons (car lap0) tmp)) | |
| 1514 (setcar lap2 (car lap0)) | |
| 1515 (setcdr lap2 tmp)) | |
| 1516 (byte-compile-log-lap " %s %s\t-->\tdup %s" lap1 lap2 lap1) | |
| 1517 (setcar lap2 (car lap1)) | |
| 1518 (setcar lap1 'byte-dup) | |
| 1519 (setcdr lap1 0) | |
| 1520 ;; The stack depth gets locally increased, so we will | |
| 1521 ;; increase maxdepth in case depth = maxdepth here. | |
| 1522 ;; This can cause the third argument to byte-code to | |
| 1523 ;; be larger than necessary. | |
| 1524 (setq add-depth 1)))) | |
| 1525 ;; | |
| 1526 ;; dup varset-X discard --> varset-X | |
| 1527 ;; dup varbind-X discard --> varbind-X | |
| 1528 ;; (the varbind variant can emerge from other optimizations) | |
| 1529 ;; | |
| 1530 ((and (eq 'byte-dup (car lap0)) | |
| 1531 (eq 'byte-discard (car lap2)) | |
| 1532 (memq (car lap1) '(byte-varset byte-varbind))) | |
| 1533 (byte-compile-log-lap " dup %s discard\t-->\t%s" lap1 lap1) | |
| 1534 (setq keep-going t | |
| 1535 rest (cdr rest)) | |
| 1536 (setq lap (delq lap0 (delq lap2 lap)))) | |
| 1537 ;; | |
| 1538 ;; not goto-X-if-nil --> goto-X-if-non-nil | |
| 1539 ;; not goto-X-if-non-nil --> goto-X-if-nil | |
| 1540 ;; | |
| 1541 ;; it is wrong to do the same thing for the -else-pop variants. | |
| 1542 ;; | |
| 1543 ((and (eq 'byte-not (car lap0)) | |
| 1544 (or (eq 'byte-goto-if-nil (car lap1)) | |
| 1545 (eq 'byte-goto-if-not-nil (car lap1)))) | |
| 1546 (byte-compile-log-lap " not %s\t-->\t%s" | |
| 1547 lap1 | |
| 1548 (cons | |
| 1549 (if (eq (car lap1) 'byte-goto-if-nil) | |
| 1550 'byte-goto-if-not-nil | |
| 1551 'byte-goto-if-nil) | |
| 1552 (cdr lap1))) | |
| 1553 (setcar lap1 (if (eq (car lap1) 'byte-goto-if-nil) | |
| 1554 'byte-goto-if-not-nil | |
| 1555 'byte-goto-if-nil)) | |
| 1556 (setq lap (delq lap0 lap)) | |
| 1557 (setq keep-going t)) | |
| 1558 ;; | |
| 1559 ;; goto-X-if-nil goto-Y X: --> goto-Y-if-non-nil X: | |
| 1560 ;; goto-X-if-non-nil goto-Y X: --> goto-Y-if-nil X: | |
| 1561 ;; | |
| 1562 ;; it is wrong to do the same thing for the -else-pop variants. | |
| 1563 ;; | |
| 1564 ((and (or (eq 'byte-goto-if-nil (car lap0)) | |
| 1565 (eq 'byte-goto-if-not-nil (car lap0))) ; gotoX | |
| 1566 (eq 'byte-goto (car lap1)) ; gotoY | |
| 1567 (eq (cdr lap0) lap2)) ; TAG X | |
| 1568 (let ((inverse (if (eq 'byte-goto-if-nil (car lap0)) | |
| 1569 'byte-goto-if-not-nil 'byte-goto-if-nil))) | |
| 1570 (byte-compile-log-lap " %s %s %s:\t-->\t%s %s:" | |
| 1571 lap0 lap1 lap2 | |
| 1572 (cons inverse (cdr lap1)) lap2) | |
| 1573 (setq lap (delq lap0 lap)) | |
| 1574 (setcar lap1 inverse) | |
| 1575 (setq keep-going t))) | |
| 1576 ;; | |
| 1577 ;; const goto-if-* --> whatever | |
| 1578 ;; | |
| 1579 ((and (eq 'byte-constant (car lap0)) | |
| 1580 (memq (car lap1) byte-conditional-ops)) | |
| 1581 (cond ((if (or (eq (car lap1) 'byte-goto-if-nil) | |
| 1582 (eq (car lap1) 'byte-goto-if-nil-else-pop)) | |
| 1583 (car (cdr lap0)) | |
| 1584 (not (car (cdr lap0)))) | |
| 1585 (byte-compile-log-lap " %s %s\t-->\t<deleted>" | |
| 1586 lap0 lap1) | |
| 1587 (setq rest (cdr rest) | |
| 1588 lap (delq lap0 (delq lap1 lap)))) | |
| 1589 (t | |
| 1590 (if (memq (car lap1) byte-goto-always-pop-ops) | |
| 1591 (progn | |
| 1592 (byte-compile-log-lap " %s %s\t-->\t%s" | |
| 1593 lap0 lap1 (cons 'byte-goto (cdr lap1))) | |
| 1594 (setq lap (delq lap0 lap))) | |
| 1595 (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 | |
| 1596 (cons 'byte-goto (cdr lap1)))) | |
| 1597 (setcar lap1 'byte-goto))) | |
| 1598 (setq keep-going t)) | |
| 1599 ;; | |
| 1600 ;; varref-X varref-X --> varref-X dup | |
| 1601 ;; varref-X [dup ...] varref-X --> varref-X [dup ...] dup | |
| 1602 ;; We don't optimize the const-X variations on this here, | |
| 1603 ;; because that would inhibit some goto optimizations; we | |
| 1604 ;; optimize the const-X case after all other optimizations. | |
| 1605 ;; | |
| 1606 ((and (eq 'byte-varref (car lap0)) | |
| 1607 (progn | |
| 1608 (setq tmp (cdr rest)) | |
| 1609 (while (eq (car (car tmp)) 'byte-dup) | |
| 1610 (setq tmp (cdr tmp))) | |
| 1611 t) | |
| 1612 (eq (cdr lap0) (cdr (car tmp))) | |
| 1613 (eq 'byte-varref (car (car tmp)))) | |
| 1614 (if (memq byte-optimize-log '(t byte)) | |
| 1615 (let ((str "")) | |
| 1616 (setq tmp2 (cdr rest)) | |
| 1617 (while (not (eq tmp tmp2)) | |
| 1618 (setq tmp2 (cdr tmp2) | |
| 1619 str (concat str " dup"))) | |
| 1620 (byte-compile-log-lap " %s%s %s\t-->\t%s%s dup" | |
| 1621 lap0 str lap0 lap0 str))) | |
| 1622 (setq keep-going t) | |
| 1623 (setcar (car tmp) 'byte-dup) | |
| 1624 (setcdr (car tmp) 0) | |
| 1625 (setq rest tmp)) | |
| 1626 ;; | |
| 1627 ;; TAG1: TAG2: --> TAG1: <deleted> | |
| 1628 ;; (and other references to TAG2 are replaced with TAG1) | |
| 1629 ;; | |
| 1630 ((and (eq (car lap0) 'TAG) | |
| 1631 (eq (car lap1) 'TAG)) | |
| 1632 (and (memq byte-optimize-log '(t byte)) | |
| 1633 (byte-compile-log " adjacent tags %d and %d merged" | |
| 1634 (nth 1 lap1) (nth 1 lap0))) | |
| 1635 (setq tmp3 lap) | |
| 1636 (while (setq tmp2 (rassq lap0 tmp3)) | |
| 1637 (setcdr tmp2 lap1) | |
| 1638 (setq tmp3 (cdr (memq tmp2 tmp3)))) | |
| 1639 (setq lap (delq lap0 lap) | |
| 1640 keep-going t)) | |
| 1641 ;; | |
| 1642 ;; unused-TAG: --> <deleted> | |
| 1643 ;; | |
| 1644 ((and (eq 'TAG (car lap0)) | |
| 1645 (not (rassq lap0 lap))) | |
| 1646 (and (memq byte-optimize-log '(t byte)) | |
| 1647 (byte-compile-log " unused tag %d removed" (nth 1 lap0))) | |
| 1648 (setq lap (delq lap0 lap) | |
| 1649 keep-going t)) | |
| 1650 ;; | |
| 1651 ;; goto ... --> goto <delete until TAG or end> | |
| 1652 ;; return ... --> return <delete until TAG or end> | |
| 1653 ;; | |
| 1654 ((and (memq (car lap0) '(byte-goto byte-return)) | |
| 1655 (not (memq (car lap1) '(TAG nil)))) | |
| 1656 (setq tmp rest) | |
| 1657 (let ((i 0) | |
| 1658 (opt-p (memq byte-optimize-log '(t lap))) | |
| 1659 str deleted) | |
| 1660 (while (and (setq tmp (cdr tmp)) | |
| 1661 (not (eq 'TAG (car (car tmp))))) | |
| 1662 (if opt-p (setq deleted (cons (car tmp) deleted) | |
| 1663 str (concat str " %s") | |
| 1664 i (1+ i)))) | |
| 1665 (if opt-p | |
| 1666 (let ((tagstr | |
| 1667 (if (eq 'TAG (car (car tmp))) | |
| 1668 (format "%d:" (car (cdr (car tmp)))) | |
| 1669 (or (car tmp) "")))) | |
| 1670 (if (< i 6) | |
| 1671 (apply 'byte-compile-log-lap-1 | |
| 1672 (concat " %s" str | |
| 1673 " %s\t-->\t%s <deleted> %s") | |
| 1674 lap0 | |
| 1675 (nconc (nreverse deleted) | |
| 1676 (list tagstr lap0 tagstr))) | |
| 1677 (byte-compile-log-lap | |
| 1678 " %s <%d unreachable op%s> %s\t-->\t%s <deleted> %s" | |
| 1679 lap0 i (if (= i 1) "" "s") | |
| 1680 tagstr lap0 tagstr)))) | |
| 1681 (rplacd rest tmp)) | |
| 1682 (setq keep-going t)) | |
| 1683 ;; | |
| 1684 ;; <safe-op> unbind --> unbind <safe-op> | |
| 1685 ;; (this may enable other optimizations.) | |
| 1686 ;; | |
| 1687 ((and (eq 'byte-unbind (car lap1)) | |
| 1688 (memq (car lap0) byte-after-unbind-ops)) | |
| 1689 (byte-compile-log-lap " %s %s\t-->\t%s %s" lap0 lap1 lap1 lap0) | |
| 1690 (setcar rest lap1) | |
| 1691 (setcar (cdr rest) lap0) | |
| 1692 (setq keep-going t)) | |
| 1693 ;; | |
| 1694 ;; varbind-X unbind-N --> discard unbind-(N-1) | |
| 1695 ;; save-excursion unbind-N --> unbind-(N-1) | |
| 1696 ;; save-restriction unbind-N --> unbind-(N-1) | |
| 1697 ;; | |
| 1698 ((and (eq 'byte-unbind (car lap1)) | |
| 1699 (memq (car lap0) '(byte-varbind byte-save-excursion | |
| 1700 byte-save-restriction)) | |
| 1701 (< 0 (cdr lap1))) | |
| 1702 (if (zerop (setcdr lap1 (1- (cdr lap1)))) | |
| 1703 (delq lap1 rest)) | |
| 1704 (if (eq (car lap0) 'byte-varbind) | |
| 1705 (setcar rest (cons 'byte-discard 0)) | |
| 1706 (setq lap (delq lap0 lap))) | |
| 1707 (byte-compile-log-lap " %s %s\t-->\t%s %s" | |
| 1708 lap0 (cons (car lap1) (1+ (cdr lap1))) | |
| 1709 (if (eq (car lap0) 'byte-varbind) | |
| 1710 (car rest) | |
| 1711 (car (cdr rest))) | |
| 1712 (if (and (/= 0 (cdr lap1)) | |
| 1713 (eq (car lap0) 'byte-varbind)) | |
| 1714 (car (cdr rest)) | |
| 1715 "")) | |
| 1716 (setq keep-going t)) | |
| 1717 ;; | |
| 1718 ;; goto*-X ... X: goto-Y --> goto*-Y | |
| 1719 ;; goto-X ... X: return --> return | |
| 1720 ;; | |
| 1721 ((and (memq (car lap0) byte-goto-ops) | |
| 1722 (memq (car (setq tmp (nth 1 (memq (cdr lap0) lap)))) | |
| 1723 '(byte-goto byte-return))) | |
| 1724 (cond ((and (not (eq tmp lap0)) | |
| 1725 (or (eq (car lap0) 'byte-goto) | |
| 1726 (eq (car tmp) 'byte-goto))) | |
| 1727 (byte-compile-log-lap " %s [%s]\t-->\t%s" | |
| 1728 (car lap0) tmp tmp) | |
| 1729 (if (eq (car tmp) 'byte-return) | |
| 1730 (setcar lap0 'byte-return)) | |
| 1731 (setcdr lap0 (cdr tmp)) | |
| 1732 (setq keep-going t)))) | |
| 1733 ;; | |
| 1734 ;; goto-*-else-pop X ... X: goto-if-* --> whatever | |
| 1735 ;; goto-*-else-pop X ... X: discard --> whatever | |
| 1736 ;; | |
| 1737 ((and (memq (car lap0) '(byte-goto-if-nil-else-pop | |
| 1738 byte-goto-if-not-nil-else-pop)) | |
| 1739 (memq (car (car (setq tmp (cdr (memq (cdr lap0) lap))))) | |
| 1740 (eval-when-compile | |
| 1741 (cons 'byte-discard byte-conditional-ops))) | |
| 1742 (not (eq lap0 (car tmp)))) | |
| 1743 (setq tmp2 (car tmp)) | |
| 1744 (setq tmp3 (assq (car lap0) '((byte-goto-if-nil-else-pop | |
| 1745 byte-goto-if-nil) | |
| 1746 (byte-goto-if-not-nil-else-pop | |
| 1747 byte-goto-if-not-nil)))) | |
| 1748 (if (memq (car tmp2) tmp3) | |
| 1749 (progn (setcar lap0 (car tmp2)) | |
| 1750 (setcdr lap0 (cdr tmp2)) | |
| 1751 (byte-compile-log-lap " %s-else-pop [%s]\t-->\t%s" | |
| 1752 (car lap0) tmp2 lap0)) | |
| 1753 ;; Get rid of the -else-pop's and jump one step further. | |
| 1754 (or (eq 'TAG (car (nth 1 tmp))) | |
| 1755 (setcdr tmp (cons (byte-compile-make-tag) | |
| 1756 (cdr tmp)))) | |
| 1757 (byte-compile-log-lap " %s [%s]\t-->\t%s <skip>" | |
| 1758 (car lap0) tmp2 (nth 1 tmp3)) | |
| 1759 (setcar lap0 (nth 1 tmp3)) | |
| 1760 (setcdr lap0 (nth 1 tmp))) | |
| 1761 (setq keep-going t)) | |
| 1762 ;; | |
| 1763 ;; const goto-X ... X: goto-if-* --> whatever | |
| 1764 ;; const goto-X ... X: discard --> whatever | |
| 1765 ;; | |
| 1766 ((and (eq (car lap0) 'byte-constant) | |
| 1767 (eq (car lap1) 'byte-goto) | |
| 1768 (memq (car (car (setq tmp (cdr (memq (cdr lap1) lap))))) | |
| 1769 (eval-when-compile | |
| 1770 (cons 'byte-discard byte-conditional-ops))) | |
| 1771 (not (eq lap1 (car tmp)))) | |
| 1772 (setq tmp2 (car tmp)) | |
| 1773 (cond ((memq (car tmp2) | |
| 1774 (if (null (car (cdr lap0))) | |
| 1775 '(byte-goto-if-nil byte-goto-if-nil-else-pop) | |
| 1776 '(byte-goto-if-not-nil | |
| 1777 byte-goto-if-not-nil-else-pop))) | |
| 1778 (byte-compile-log-lap " %s goto [%s]\t-->\t%s %s" | |
| 1779 lap0 tmp2 lap0 tmp2) | |
| 1780 (setcar lap1 (car tmp2)) | |
| 1781 (setcdr lap1 (cdr tmp2)) | |
| 1782 ;; Let next step fix the (const,goto-if*) sequence. | |
| 1783 (setq rest (cons nil rest))) | |
| 1784 (t | |
| 1785 ;; Jump one step further | |
| 1786 (byte-compile-log-lap | |
| 1787 " %s goto [%s]\t-->\t<deleted> goto <skip>" | |
| 1788 lap0 tmp2) | |
| 1789 (or (eq 'TAG (car (nth 1 tmp))) | |
| 1790 (setcdr tmp (cons (byte-compile-make-tag) | |
| 1791 (cdr tmp)))) | |
| 1792 (setcdr lap1 (car (cdr tmp))) | |
| 1793 (setq lap (delq lap0 lap)))) | |
| 1794 (setq keep-going t)) | |
| 1795 ;; | |
| 1796 ;; X: varref-Y ... varset-Y goto-X --> | |
| 1797 ;; X: varref-Y Z: ... dup varset-Y goto-Z | |
| 1798 ;; (varset-X goto-BACK, BACK: varref-X --> copy the varref down.) | |
| 1799 ;; (This is so usual for while loops that it is worth handling). | |
| 1800 ;; | |
| 1801 ((and (eq (car lap1) 'byte-varset) | |
| 1802 (eq (car lap2) 'byte-goto) | |
| 1803 (not (memq (cdr lap2) rest)) ;Backwards jump | |
| 1804 (eq (car (car (setq tmp (cdr (memq (cdr lap2) lap))))) | |
| 1805 'byte-varref) | |
| 1806 (eq (cdr (car tmp)) (cdr lap1)) | |
| 1807 (not (memq (car (cdr lap1)) byte-boolean-vars))) | |
| 1808 ;;(byte-compile-log-lap " Pulled %s to end of loop" (car tmp)) | |
| 1809 (let ((newtag (byte-compile-make-tag))) | |
| 1810 (byte-compile-log-lap | |
| 1811 " %s: %s ... %s %s\t-->\t%s: %s %s: ... %s %s %s" | |
| 1812 (nth 1 (cdr lap2)) (car tmp) | |
| 1813 lap1 lap2 | |
| 1814 (nth 1 (cdr lap2)) (car tmp) | |
| 1815 (nth 1 newtag) 'byte-dup lap1 | |
| 1816 (cons 'byte-goto newtag) | |
| 1817 ) | |
| 1818 (setcdr rest (cons (cons 'byte-dup 0) (cdr rest))) | |
| 1819 (setcdr tmp (cons (setcdr lap2 newtag) (cdr tmp)))) | |
| 1820 (setq add-depth 1) | |
| 1821 (setq keep-going t)) | |
| 1822 ;; | |
| 1823 ;; goto-X Y: ... X: goto-if*-Y --> goto-if-not-*-X+1 Y: | |
| 1824 ;; (This can pull the loop test to the end of the loop) | |
| 1825 ;; | |
| 1826 ((and (eq (car lap0) 'byte-goto) | |
| 1827 (eq (car lap1) 'TAG) | |
| 1828 (eq lap1 | |
| 1829 (cdr (car (setq tmp (cdr (memq (cdr lap0) lap)))))) | |
| 1830 (memq (car (car tmp)) | |
| 1831 '(byte-goto byte-goto-if-nil byte-goto-if-not-nil | |
| 1832 byte-goto-if-nil-else-pop))) | |
| 1833 ;; (byte-compile-log-lap " %s %s, %s %s --> moved conditional" | |
| 1834 ;; lap0 lap1 (cdr lap0) (car tmp)) | |
| 1835 (let ((newtag (byte-compile-make-tag))) | |
| 1836 (byte-compile-log-lap | |
| 1837 "%s %s: ... %s: %s\t-->\t%s ... %s:" | |
| 1838 lap0 (nth 1 lap1) (nth 1 (cdr lap0)) (car tmp) | |
| 1839 (cons (cdr (assq (car (car tmp)) | |
| 1840 '((byte-goto-if-nil . byte-goto-if-not-nil) | |
| 1841 (byte-goto-if-not-nil . byte-goto-if-nil) | |
| 1842 (byte-goto-if-nil-else-pop . | |
| 1843 byte-goto-if-not-nil-else-pop) | |
| 1844 (byte-goto-if-not-nil-else-pop . | |
| 1845 byte-goto-if-nil-else-pop)))) | |
| 1846 newtag) | |
| 1847 | |
| 1848 (nth 1 newtag) | |
| 1849 ) | |
| 1850 (setcdr tmp (cons (setcdr lap0 newtag) (cdr tmp))) | |
| 1851 (if (eq (car (car tmp)) 'byte-goto-if-nil-else-pop) | |
| 1852 ;; We can handle this case but not the -if-not-nil case, | |
| 1853 ;; because we won't know which non-nil constant to push. | |
| 1854 (setcdr rest (cons (cons 'byte-constant | |
| 1855 (byte-compile-get-constant nil)) | |
| 1856 (cdr rest)))) | |
| 1857 (setcar lap0 (nth 1 (memq (car (car tmp)) | |
| 1858 '(byte-goto-if-nil-else-pop | |
| 1859 byte-goto-if-not-nil | |
| 1860 byte-goto-if-nil | |
| 1861 byte-goto-if-not-nil | |
| 1862 byte-goto byte-goto)))) | |
| 1863 ) | |
| 1864 (setq keep-going t)) | |
| 1865 ) | |
| 1866 (setq rest (cdr rest))) | |
| 1867 ) | |
| 1868 ;; Cleanup stage: | |
| 1869 ;; Rebuild byte-compile-constants / byte-compile-variables. | |
| 1870 ;; Simple optimizations that would inhibit other optimizations if they | |
| 1871 ;; were done in the optimizing loop, and optimizations which there is no | |
| 1872 ;; need to do more than once. | |
| 1873 (setq byte-compile-constants nil | |
| 1874 byte-compile-variables nil) | |
| 1875 (setq rest lap) | |
| 1876 (while rest | |
| 1877 (setq lap0 (car rest) | |
| 1878 lap1 (nth 1 rest)) | |
| 1879 (if (memq (car lap0) byte-constref-ops) | |
| 1880 (if (eq (cdr lap0) 'byte-constant) | |
| 1881 (or (memq (cdr lap0) byte-compile-variables) | |
| 1882 (setq byte-compile-variables (cons (cdr lap0) | |
| 1883 byte-compile-variables))) | |
| 1884 (or (memq (cdr lap0) byte-compile-constants) | |
| 1885 (setq byte-compile-constants (cons (cdr lap0) | |
| 1886 byte-compile-constants))))) | |
| 1887 (cond (;; | |
| 1888 ;; const-C varset-X const-C --> const-C dup varset-X | |
| 1889 ;; const-C varbind-X const-C --> const-C dup varbind-X | |
| 1890 ;; | |
| 1891 (and (eq (car lap0) 'byte-constant) | |
| 1892 (eq (car (nth 2 rest)) 'byte-constant) | |
| 1893 (eq (cdr lap0) (car (nth 2 rest))) | |
| 1894 (memq (car lap1) '(byte-varbind byte-varset))) | |
| 1895 (byte-compile-log-lap " %s %s %s\t-->\t%s dup %s" | |
| 1896 lap0 lap1 lap0 lap0 lap1) | |
| 1897 (setcar (cdr (cdr rest)) (cons (car lap1) (cdr lap1))) | |
| 1898 (setcar (cdr rest) (cons 'byte-dup 0)) | |
| 1899 (setq add-depth 1)) | |
| 1900 ;; | |
| 1901 ;; const-X [dup/const-X ...] --> const-X [dup ...] dup | |
| 1902 ;; varref-X [dup/varref-X ...] --> varref-X [dup ...] dup | |
| 1903 ;; | |
| 1904 ((memq (car lap0) '(byte-constant byte-varref)) | |
| 1905 (setq tmp rest | |
| 1906 tmp2 nil) | |
| 1907 (while (progn | |
| 1908 (while (eq 'byte-dup (car (car (setq tmp (cdr tmp)))))) | |
| 1909 (and (eq (cdr lap0) (cdr (car tmp))) | |
| 1910 (eq (car lap0) (car (car tmp))))) | |
| 1911 (setcar tmp (cons 'byte-dup 0)) | |
| 1912 (setq tmp2 t)) | |
| 1913 (if tmp2 | |
| 1914 (byte-compile-log-lap | |
| 1915 " %s [dup/%s]...\t-->\t%s dup..." lap0 lap0 lap0))) | |
| 1916 ;; | |
| 1917 ;; unbind-N unbind-M --> unbind-(N+M) | |
| 1918 ;; | |
| 1919 ((and (eq 'byte-unbind (car lap0)) | |
| 1920 (eq 'byte-unbind (car lap1))) | |
| 1921 (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 | |
| 1922 (cons 'byte-unbind | |
| 1923 (+ (cdr lap0) (cdr lap1)))) | |
| 1924 (setq keep-going t) | |
| 1925 (setq lap (delq lap0 lap)) | |
| 1926 (setcdr lap1 (+ (cdr lap1) (cdr lap0)))) | |
| 1927 ) | |
| 1928 (setq rest (cdr rest))) | |
| 1929 (setq byte-compile-maxdepth (+ byte-compile-maxdepth add-depth))) | |
| 1930 lap) | |
| 1931 | |
| 1932 (provide 'byte-optimize) | |
| 1933 | |
| 1934 | |
| 1935 ;; To avoid "lisp nesting exceeds max-lisp-eval-depth" when this file compiles | |
| 1936 ;; itself, compile some of its most used recursive functions (at load time). | |
| 1937 ;; | |
| 1938 (eval-when-compile | |
| 1939 (or (compiled-function-p (symbol-function 'byte-optimize-form)) | |
| 1940 (assq 'byte-code (symbol-function 'byte-optimize-form)) | |
| 1941 (let ((byte-optimize nil) | |
| 1942 (byte-compile-warnings nil)) | |
| 1943 (mapcar '(lambda (x) | |
| 1944 (or noninteractive (message "compiling %s..." x)) | |
| 1945 (byte-compile x) | |
| 1946 (or noninteractive (message "compiling %s...done" x))) | |
| 1947 '(byte-optimize-form | |
| 1948 byte-optimize-body | |
| 1949 byte-optimize-predicate | |
| 1950 byte-optimize-binary-predicate | |
| 1951 ;; Inserted some more than necessary, to speed it up. | |
| 1952 byte-optimize-form-code-walker | |
| 1953 byte-optimize-lapcode)))) | |
| 1954 nil) | |
| 1955 | |
| 1956 ;;; byte-optimize.el ends here |