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55535639 | 1 | ;;; byte-opt.el --- the optimization passes of the emacs-lisp byte compiler |
3eac9910 | 2 | |
3731a850 | 3 | ;; Copyright (C) 1991, 1994, 2000, 2001, 2002, 2003, 2004, |
f0fa15c5 | 4 | ;; 2005, 2006, 2007 Free Software Foundation, Inc. |
3eac9910 JB |
5 | |
6 | ;; Author: Jamie Zawinski <jwz@lucid.com> | |
7 | ;; Hallvard Furuseth <hbf@ulrik.uio.no> | |
e1f0df62 | 8 | ;; Maintainer: FSF |
3eac9910 | 9 | ;; Keywords: internal |
1c393159 JB |
10 | |
11 | ;; This file is part of GNU Emacs. | |
12 | ||
13 | ;; GNU Emacs is free software; you can redistribute it and/or modify | |
14 | ;; it under the terms of the GNU General Public License as published by | |
3eac9910 | 15 | ;; the Free Software Foundation; either version 2, or (at your option) |
1c393159 JB |
16 | ;; any later version. |
17 | ||
18 | ;; GNU Emacs is distributed in the hope that it will be useful, | |
19 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
20 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
21 | ;; GNU General Public License for more details. | |
22 | ||
23 | ;; You should have received a copy of the GNU General Public License | |
b578f267 | 24 | ;; along with GNU Emacs; see the file COPYING. If not, write to the |
3a35cf56 LK |
25 | ;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
26 | ;; Boston, MA 02110-1301, USA. | |
1c393159 | 27 | |
3eac9910 JB |
28 | ;;; Commentary: |
29 | ||
b578f267 EN |
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 | |
a1506d29 | 35 | ;; makes it be a VW Bug with fuel injection and a turbocharger... You're |
b578f267 EN |
36 | ;; still not going to make it go faster than 70 mph, but it might be easier |
37 | ;; to get it there. | |
38 | ;; | |
1c393159 | 39 | |
b578f267 EN |
40 | ;; TO DO: |
41 | ;; | |
72d8b544 | 42 | ;; (apply (lambda (x &rest y) ...) 1 (foo)) |
b578f267 EN |
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) | |
b578f267 EN |
54 | ;; (put 'inhibit-quit 'binding-is-magic t) |
55 | ;; (put 'quit-flag 'binding-is-magic t) | |
56 | ;; (put 't 'binding-is-magic t) | |
57 | ;; (put 'nil 'binding-is-magic t) | |
58 | ;; possibly also | |
59 | ;; (put 'gc-cons-threshold 'binding-is-magic t) | |
60 | ;; (put 'track-mouse 'binding-is-magic t) | |
61 | ;; others? | |
62 | ;; | |
63 | ;; Simple defsubsts often produce forms like | |
64 | ;; (let ((v1 (f1)) (v2 (f2)) ...) | |
65 | ;; (FN v1 v2 ...)) | |
a1506d29 | 66 | ;; It would be nice if we could optimize this to |
b578f267 EN |
67 | ;; (FN (f1) (f2) ...) |
68 | ;; but we can't unless FN is dynamically-safe (it might be dynamically | |
69 | ;; referring to the bindings that the lambda arglist established.) | |
70 | ;; One of the uncountable lossages introduced by dynamic scope... | |
71 | ;; | |
a1506d29 | 72 | ;; Maybe there should be a control-structure that says "turn on |
b578f267 EN |
73 | ;; fast-and-loose type-assumptive optimizations here." Then when |
74 | ;; we see a form like (car foo) we can from then on assume that | |
75 | ;; the variable foo is of type cons, and optimize based on that. | |
a1506d29 | 76 | ;; But, this won't win much because of (you guessed it) dynamic |
b578f267 EN |
77 | ;; scope. Anything down the stack could change the value. |
78 | ;; (Another reason it doesn't work is that it is perfectly valid | |
79 | ;; to call car with a null argument.) A better approach might | |
80 | ;; be to allow type-specification of the form | |
81 | ;; (put 'foo 'arg-types '(float (list integer) dynamic)) | |
82 | ;; (put 'foo 'result-type 'bool) | |
83 | ;; It should be possible to have these types checked to a certain | |
84 | ;; degree. | |
85 | ;; | |
86 | ;; collapse common subexpressions | |
87 | ;; | |
88 | ;; It would be nice if redundant sequences could be factored out as well, | |
89 | ;; when they are known to have no side-effects: | |
90 | ;; (list (+ a b c) (+ a b c)) --> a b add c add dup list-2 | |
91 | ;; but beware of traps like | |
92 | ;; (cons (list x y) (list x y)) | |
93 | ;; | |
94 | ;; Tail-recursion elimination is not really possible in Emacs Lisp. | |
95 | ;; Tail-recursion elimination is almost always impossible when all variables | |
96 | ;; have dynamic scope, but given that the "return" byteop requires the | |
97 | ;; binding stack to be empty (rather than emptying it itself), there can be | |
98 | ;; no truly tail-recursive Emacs Lisp functions that take any arguments or | |
99 | ;; make any bindings. | |
100 | ;; | |
101 | ;; Here is an example of an Emacs Lisp function which could safely be | |
102 | ;; byte-compiled tail-recursively: | |
103 | ;; | |
104 | ;; (defun tail-map (fn list) | |
105 | ;; (cond (list | |
106 | ;; (funcall fn (car list)) | |
107 | ;; (tail-map fn (cdr list))))) | |
108 | ;; | |
109 | ;; However, if there was even a single let-binding around the COND, | |
110 | ;; it could not be byte-compiled, because there would be an "unbind" | |
a1506d29 | 111 | ;; byte-op between the final "call" and "return." Adding a |
b578f267 EN |
112 | ;; Bunbind_all byteop would fix this. |
113 | ;; | |
114 | ;; (defun foo (x y z) ... (foo a b c)) | |
115 | ;; ... (const foo) (varref a) (varref b) (varref c) (call 3) END: (return) | |
116 | ;; ... (varref a) (varbind x) (varref b) (varbind y) (varref c) (varbind z) (goto 0) END: (unbind-all) (return) | |
117 | ;; ... (varref a) (varset x) (varref b) (varset y) (varref c) (varset z) (goto 0) END: (return) | |
118 | ;; | |
119 | ;; this also can be considered tail recursion: | |
120 | ;; | |
121 | ;; ... (const foo) (varref a) (call 1) (goto X) ... X: (return) | |
122 | ;; could generalize this by doing the optimization | |
123 | ;; (goto X) ... X: (return) --> (return) | |
124 | ;; | |
125 | ;; But this doesn't solve all of the problems: although by doing tail- | |
126 | ;; recursion elimination in this way, the call-stack does not grow, the | |
127 | ;; binding-stack would grow with each recursive step, and would eventually | |
128 | ;; overflow. I don't believe there is any way around this without lexical | |
129 | ;; scope. | |
130 | ;; | |
131 | ;; Wouldn't it be nice if Emacs Lisp had lexical scope. | |
132 | ;; | |
a1506d29 JB |
133 | ;; Idea: the form (lexical-scope) in a file means that the file may be |
134 | ;; compiled lexically. This proclamation is file-local. Then, within | |
b578f267 EN |
135 | ;; that file, "let" would establish lexical bindings, and "let-dynamic" |
136 | ;; would do things the old way. (Or we could use CL "declare" forms.) | |
137 | ;; We'd have to notice defvars and defconsts, since those variables should | |
138 | ;; always be dynamic, and attempting to do a lexical binding of them | |
139 | ;; should simply do a dynamic binding instead. | |
140 | ;; But! We need to know about variables that were not necessarily defvarred | |
141 | ;; in the file being compiled (doing a boundp check isn't good enough.) | |
142 | ;; Fdefvar() would have to be modified to add something to the plist. | |
143 | ;; | |
a1506d29 JB |
144 | ;; A major disadvantage of this scheme is that the interpreter and compiler |
145 | ;; would have different semantics for files compiled with (dynamic-scope). | |
b578f267 | 146 | ;; Since this would be a file-local optimization, there would be no way to |
a1506d29 | 147 | ;; modify the interpreter to obey this (unless the loader was hacked |
b578f267 | 148 | ;; in some grody way, but that's a really bad idea.) |
97e6527f KH |
149 | |
150 | ;; Other things to consider: | |
151 | ||
e856a453 SM |
152 | ;; ;; Associative math should recognize subcalls to identical function: |
153 | ;; (disassemble (lambda (x) (+ (+ (foo) 1) (+ (bar) 2)))) | |
154 | ;; ;; This should generate the same as (1+ x) and (1- x) | |
c1fe6512 | 155 | |
e856a453 SM |
156 | ;; (disassemble (lambda (x) (cons (+ x 1) (- x 1)))) |
157 | ;; ;; An awful lot of functions always return a non-nil value. If they're | |
158 | ;; ;; error free also they may act as true-constants. | |
c1fe6512 | 159 | |
e856a453 SM |
160 | ;; (disassemble (lambda (x) (and (point) (foo)))) |
161 | ;; ;; When | |
162 | ;; ;; - all but one arguments to a function are constant | |
163 | ;; ;; - the non-constant argument is an if-expression (cond-expression?) | |
164 | ;; ;; then the outer function can be distributed. If the guarding | |
165 | ;; ;; condition is side-effect-free [assignment-free] then the other | |
166 | ;; ;; arguments may be any expressions. Since, however, the code size | |
167 | ;; ;; can increase this way they should be "simple". Compare: | |
c1fe6512 | 168 | |
e856a453 SM |
169 | ;; (disassemble (lambda (x) (eq (if (point) 'a 'b) 'c))) |
170 | ;; (disassemble (lambda (x) (if (point) (eq 'a 'c) (eq 'b 'c)))) | |
c1fe6512 | 171 | |
e856a453 SM |
172 | ;; ;; (car (cons A B)) -> (prog1 A B) |
173 | ;; (disassemble (lambda (x) (car (cons (foo) 42)))) | |
c1fe6512 | 174 | |
e856a453 SM |
175 | ;; ;; (cdr (cons A B)) -> (progn A B) |
176 | ;; (disassemble (lambda (x) (cdr (cons 42 (foo))))) | |
c1fe6512 | 177 | |
e856a453 SM |
178 | ;; ;; (car (list A B ...)) -> (prog1 A B ...) |
179 | ;; (disassemble (lambda (x) (car (list (foo) 42 (bar))))) | |
c1fe6512 | 180 | |
e856a453 SM |
181 | ;; ;; (cdr (list A B ...)) -> (progn A (list B ...)) |
182 | ;; (disassemble (lambda (x) (cdr (list 42 (foo) (bar))))) | |
97e6527f | 183 | |
1c393159 | 184 | |
3eac9910 | 185 | ;;; Code: |
1c393159 | 186 | |
c144230d MR |
187 | (require 'bytecomp) |
188 | ||
1c393159 JB |
189 | (defun byte-compile-log-lap-1 (format &rest args) |
190 | (if (aref byte-code-vector 0) | |
55535639 | 191 | (error "The old version of the disassembler is loaded. Reload new-bytecomp as well")) |
1c393159 JB |
192 | (byte-compile-log-1 |
193 | (apply 'format format | |
194 | (let (c a) | |
72d8b544 | 195 | (mapcar (lambda (arg) |
1c393159 JB |
196 | (if (not (consp arg)) |
197 | (if (and (symbolp arg) | |
198 | (string-match "^byte-" (symbol-name arg))) | |
199 | (intern (substring (symbol-name arg) 5)) | |
200 | arg) | |
201 | (if (integerp (setq c (car arg))) | |
202 | (error "non-symbolic byte-op %s" c)) | |
203 | (if (eq c 'TAG) | |
204 | (setq c arg) | |
205 | (setq a (cond ((memq c byte-goto-ops) | |
206 | (car (cdr (cdr arg)))) | |
207 | ((memq c byte-constref-ops) | |
208 | (car (cdr arg))) | |
209 | (t (cdr arg)))) | |
210 | (setq c (symbol-name c)) | |
211 | (if (string-match "^byte-." c) | |
212 | (setq c (intern (substring c 5))))) | |
213 | (if (eq c 'constant) (setq c 'const)) | |
214 | (if (and (eq (cdr arg) 0) | |
215 | (not (memq c '(unbind call const)))) | |
216 | c | |
217 | (format "(%s %s)" c a)))) | |
218 | args))))) | |
219 | ||
220 | (defmacro byte-compile-log-lap (format-string &rest args) | |
e856a453 SM |
221 | `(and (memq byte-optimize-log '(t byte)) |
222 | (byte-compile-log-lap-1 ,format-string ,@args))) | |
1c393159 JB |
223 | |
224 | \f | |
225 | ;;; byte-compile optimizers to support inlining | |
226 | ||
227 | (put 'inline 'byte-optimizer 'byte-optimize-inline-handler) | |
228 | ||
229 | (defun byte-optimize-inline-handler (form) | |
230 | "byte-optimize-handler for the `inline' special-form." | |
231 | (cons 'progn | |
232 | (mapcar | |
72d8b544 | 233 | (lambda (sexp) |
08d72d13 SM |
234 | (let ((f (car-safe sexp))) |
235 | (if (and (symbolp f) | |
236 | (or (cdr (assq f byte-compile-function-environment)) | |
237 | (not (or (not (fboundp f)) | |
238 | (cdr (assq f byte-compile-macro-environment)) | |
239 | (and (consp (setq f (symbol-function f))) | |
240 | (eq (car f) 'macro)) | |
241 | (subrp f))))) | |
242 | (byte-compile-inline-expand sexp) | |
243 | sexp))) | |
1c393159 JB |
244 | (cdr form)))) |
245 | ||
246 | ||
70e1dad8 RS |
247 | ;; Splice the given lap code into the current instruction stream. |
248 | ;; If it has any labels in it, you're responsible for making sure there | |
249 | ;; are no collisions, and that byte-compile-tag-number is reasonable | |
250 | ;; after this is spliced in. The provided list is destroyed. | |
1c393159 | 251 | (defun byte-inline-lapcode (lap) |
1c393159 JB |
252 | (setq byte-compile-output (nconc (nreverse lap) byte-compile-output))) |
253 | ||
1c393159 JB |
254 | (defun byte-compile-inline-expand (form) |
255 | (let* ((name (car form)) | |
256 | (fn (or (cdr (assq name byte-compile-function-environment)) | |
257 | (and (fboundp name) (symbol-function name))))) | |
258 | (if (null fn) | |
259 | (progn | |
244bbdc5 | 260 | (byte-compile-warn "attempt to inline `%s' before it was defined" |
c59a4192 | 261 | name) |
1c393159 JB |
262 | form) |
263 | ;; else | |
78ecf55a | 264 | (when (and (consp fn) (eq (car fn) 'autoload)) |
28881a56 | 265 | (load (nth 1 fn)) |
78ecf55a GM |
266 | (setq fn (or (and (fboundp name) (symbol-function name)) |
267 | (cdr (assq name byte-compile-function-environment))))) | |
1c393159 | 268 | (if (and (consp fn) (eq (car fn) 'autoload)) |
0abfa90d | 269 | (error "File `%s' didn't define `%s'" (nth 1 fn) name)) |
f61b7b7f | 270 | (if (and (symbolp fn) (not (eq fn t))) |
1c393159 | 271 | (byte-compile-inline-expand (cons fn (cdr form))) |
96d699f3 | 272 | (if (byte-code-function-p fn) |
70b40ea1 | 273 | (let (string) |
2b29a376 | 274 | (fetch-bytecode fn) |
70b40ea1 | 275 | (setq string (aref fn 1)) |
e856a453 | 276 | ;; Isn't it an error for `string' not to be unibyte?? --stef |
70b40ea1 RS |
277 | (if (fboundp 'string-as-unibyte) |
278 | (setq string (string-as-unibyte string))) | |
e856a453 SM |
279 | (cons `(lambda ,(aref fn 0) |
280 | (byte-code ,string ,(aref fn 2) ,(aref fn 3))) | |
2b29a376 | 281 | (cdr form))) |
223a2a62 KH |
282 | (if (eq (car-safe fn) 'lambda) |
283 | (cons fn (cdr form)) | |
284 | ;; Give up on inlining. | |
285 | form)))))) | |
1c393159 | 286 | |
e856a453 | 287 | ;; ((lambda ...) ...) |
1c393159 JB |
288 | (defun byte-compile-unfold-lambda (form &optional name) |
289 | (or name (setq name "anonymous lambda")) | |
290 | (let ((lambda (car form)) | |
291 | (values (cdr form))) | |
96d699f3 | 292 | (if (byte-code-function-p lambda) |
7e1dae73 JB |
293 | (setq lambda (list 'lambda (aref lambda 0) |
294 | (list 'byte-code (aref lambda 1) | |
295 | (aref lambda 2) (aref lambda 3))))) | |
1c393159 JB |
296 | (let ((arglist (nth 1 lambda)) |
297 | (body (cdr (cdr lambda))) | |
298 | optionalp restp | |
299 | bindings) | |
300 | (if (and (stringp (car body)) (cdr body)) | |
301 | (setq body (cdr body))) | |
302 | (if (and (consp (car body)) (eq 'interactive (car (car body)))) | |
303 | (setq body (cdr body))) | |
304 | (while arglist | |
305 | (cond ((eq (car arglist) '&optional) | |
306 | ;; ok, I'll let this slide because funcall_lambda() does... | |
307 | ;; (if optionalp (error "multiple &optional keywords in %s" name)) | |
308 | (if restp (error "&optional found after &rest in %s" name)) | |
309 | (if (null (cdr arglist)) | |
310 | (error "nothing after &optional in %s" name)) | |
311 | (setq optionalp t)) | |
312 | ((eq (car arglist) '&rest) | |
313 | ;; ...but it is by no stretch of the imagination a reasonable | |
314 | ;; thing that funcall_lambda() allows (&rest x y) and | |
315 | ;; (&rest x &optional y) in arglists. | |
316 | (if (null (cdr arglist)) | |
317 | (error "nothing after &rest in %s" name)) | |
318 | (if (cdr (cdr arglist)) | |
319 | (error "multiple vars after &rest in %s" name)) | |
320 | (setq restp t)) | |
321 | (restp | |
322 | (setq bindings (cons (list (car arglist) | |
323 | (and values (cons 'list values))) | |
324 | bindings) | |
325 | values nil)) | |
326 | ((and (not optionalp) (null values)) | |
244bbdc5 | 327 | (byte-compile-warn "attempt to open-code `%s' with too few arguments" name) |
1c393159 JB |
328 | (setq arglist nil values 'too-few)) |
329 | (t | |
330 | (setq bindings (cons (list (car arglist) (car values)) | |
331 | bindings) | |
332 | values (cdr values)))) | |
333 | (setq arglist (cdr arglist))) | |
334 | (if values | |
335 | (progn | |
336 | (or (eq values 'too-few) | |
337 | (byte-compile-warn | |
244bbdc5 | 338 | "attempt to open-code `%s' with too many arguments" name)) |
1c393159 | 339 | form) |
a1506d29 | 340 | |
936ae731 GM |
341 | ;; The following leads to infinite recursion when loading a |
342 | ;; file containing `(defsubst f () (f))', and then trying to | |
343 | ;; byte-compile that file. | |
344 | ;(setq body (mapcar 'byte-optimize-form body))) | |
a1506d29 JB |
345 | |
346 | (let ((newform | |
1c393159 JB |
347 | (if bindings |
348 | (cons 'let (cons (nreverse bindings) body)) | |
349 | (cons 'progn body)))) | |
350 | (byte-compile-log " %s\t==>\t%s" form newform) | |
351 | newform))))) | |
352 | ||
353 | \f | |
354 | ;;; implementing source-level optimizers | |
355 | ||
356 | (defun byte-optimize-form-code-walker (form for-effect) | |
357 | ;; | |
358 | ;; For normal function calls, We can just mapcar the optimizer the cdr. But | |
359 | ;; we need to have special knowledge of the syntax of the special forms | |
360 | ;; like let and defun (that's why they're special forms :-). (Actually, | |
361 | ;; the important aspect is that they are subrs that don't evaluate all of | |
362 | ;; their args.) | |
363 | ;; | |
364 | (let ((fn (car-safe form)) | |
365 | tmp) | |
366 | (cond ((not (consp form)) | |
367 | (if (not (and for-effect | |
368 | (or byte-compile-delete-errors | |
369 | (not (symbolp form)) | |
370 | (eq form t)))) | |
371 | form)) | |
372 | ((eq fn 'quote) | |
373 | (if (cdr (cdr form)) | |
244bbdc5 | 374 | (byte-compile-warn "malformed quote form: `%s'" |
1c393159 JB |
375 | (prin1-to-string form))) |
376 | ;; map (quote nil) to nil to simplify optimizer logic. | |
377 | ;; map quoted constants to nil if for-effect (just because). | |
378 | (and (nth 1 form) | |
379 | (not for-effect) | |
380 | form)) | |
96d699f3 | 381 | ((or (byte-code-function-p fn) |
1c393159 JB |
382 | (eq 'lambda (car-safe fn))) |
383 | (byte-compile-unfold-lambda form)) | |
384 | ((memq fn '(let let*)) | |
385 | ;; recursively enter the optimizer for the bindings and body | |
386 | ;; of a let or let*. This for depth-firstness: forms that | |
387 | ;; are more deeply nested are optimized first. | |
388 | (cons fn | |
389 | (cons | |
72d8b544 | 390 | (mapcar (lambda (binding) |
1c393159 JB |
391 | (if (symbolp binding) |
392 | binding | |
393 | (if (cdr (cdr binding)) | |
244bbdc5 | 394 | (byte-compile-warn "malformed let binding: `%s'" |
1c393159 JB |
395 | (prin1-to-string binding))) |
396 | (list (car binding) | |
397 | (byte-optimize-form (nth 1 binding) nil)))) | |
398 | (nth 1 form)) | |
399 | (byte-optimize-body (cdr (cdr form)) for-effect)))) | |
400 | ((eq fn 'cond) | |
401 | (cons fn | |
72d8b544 | 402 | (mapcar (lambda (clause) |
1c393159 JB |
403 | (if (consp clause) |
404 | (cons | |
405 | (byte-optimize-form (car clause) nil) | |
406 | (byte-optimize-body (cdr clause) for-effect)) | |
244bbdc5 | 407 | (byte-compile-warn "malformed cond form: `%s'" |
1c393159 JB |
408 | (prin1-to-string clause)) |
409 | clause)) | |
410 | (cdr form)))) | |
411 | ((eq fn 'progn) | |
412 | ;; as an extra added bonus, this simplifies (progn <x>) --> <x> | |
413 | (if (cdr (cdr form)) | |
414 | (progn | |
415 | (setq tmp (byte-optimize-body (cdr form) for-effect)) | |
416 | (if (cdr tmp) (cons 'progn tmp) (car tmp))) | |
417 | (byte-optimize-form (nth 1 form) for-effect))) | |
418 | ((eq fn 'prog1) | |
419 | (if (cdr (cdr form)) | |
420 | (cons 'prog1 | |
421 | (cons (byte-optimize-form (nth 1 form) for-effect) | |
422 | (byte-optimize-body (cdr (cdr form)) t))) | |
423 | (byte-optimize-form (nth 1 form) for-effect))) | |
424 | ((eq fn 'prog2) | |
425 | (cons 'prog2 | |
426 | (cons (byte-optimize-form (nth 1 form) t) | |
427 | (cons (byte-optimize-form (nth 2 form) for-effect) | |
428 | (byte-optimize-body (cdr (cdr (cdr form))) t))))) | |
a1506d29 | 429 | |
2754fefa | 430 | ((memq fn '(save-excursion save-restriction save-current-buffer)) |
1c393159 JB |
431 | ;; those subrs which have an implicit progn; it's not quite good |
432 | ;; enough to treat these like normal function calls. | |
433 | ;; This can turn (save-excursion ...) into (save-excursion) which | |
434 | ;; will be optimized away in the lap-optimize pass. | |
435 | (cons fn (byte-optimize-body (cdr form) for-effect))) | |
a1506d29 | 436 | |
1c393159 JB |
437 | ((eq fn 'with-output-to-temp-buffer) |
438 | ;; this is just like the above, except for the first argument. | |
439 | (cons fn | |
440 | (cons | |
441 | (byte-optimize-form (nth 1 form) nil) | |
442 | (byte-optimize-body (cdr (cdr form)) for-effect)))) | |
a1506d29 | 443 | |
1c393159 | 444 | ((eq fn 'if) |
aefd695a | 445 | (when (< (length form) 3) |
244bbdc5 | 446 | (byte-compile-warn "too few arguments for `if'")) |
1c393159 JB |
447 | (cons fn |
448 | (cons (byte-optimize-form (nth 1 form) nil) | |
449 | (cons | |
450 | (byte-optimize-form (nth 2 form) for-effect) | |
451 | (byte-optimize-body (nthcdr 3 form) for-effect))))) | |
a1506d29 | 452 | |
1c393159 JB |
453 | ((memq fn '(and or)) ; remember, and/or are control structures. |
454 | ;; take forms off the back until we can't any more. | |
eb8c3be9 | 455 | ;; In the future it could conceivably be a problem that the |
1c393159 JB |
456 | ;; subexpressions of these forms are optimized in the reverse |
457 | ;; order, but it's ok for now. | |
458 | (if for-effect | |
459 | (let ((backwards (reverse (cdr form)))) | |
460 | (while (and backwards | |
461 | (null (setcar backwards | |
462 | (byte-optimize-form (car backwards) | |
463 | for-effect)))) | |
464 | (setq backwards (cdr backwards))) | |
465 | (if (and (cdr form) (null backwards)) | |
466 | (byte-compile-log | |
467 | " all subforms of %s called for effect; deleted" form)) | |
468 | (and backwards | |
e8f3c355 | 469 | (cons fn (nreverse (mapcar 'byte-optimize-form backwards))))) |
1c393159 JB |
470 | (cons fn (mapcar 'byte-optimize-form (cdr form))))) |
471 | ||
472 | ((eq fn 'interactive) | |
244bbdc5 | 473 | (byte-compile-warn "misplaced interactive spec: `%s'" |
1c393159 JB |
474 | (prin1-to-string form)) |
475 | nil) | |
a1506d29 | 476 | |
1c393159 JB |
477 | ((memq fn '(defun defmacro function |
478 | condition-case save-window-excursion)) | |
479 | ;; These forms are compiled as constants or by breaking out | |
480 | ;; all the subexpressions and compiling them separately. | |
481 | form) | |
482 | ||
483 | ((eq fn 'unwind-protect) | |
484 | ;; the "protected" part of an unwind-protect is compiled (and thus | |
485 | ;; optimized) as a top-level form, so don't do it here. But the | |
486 | ;; non-protected part has the same for-effect status as the | |
487 | ;; unwind-protect itself. (The protected part is always for effect, | |
488 | ;; but that isn't handled properly yet.) | |
489 | (cons fn | |
490 | (cons (byte-optimize-form (nth 1 form) for-effect) | |
491 | (cdr (cdr form))))) | |
a1506d29 | 492 | |
1c393159 JB |
493 | ((eq fn 'catch) |
494 | ;; the body of a catch is compiled (and thus optimized) as a | |
495 | ;; top-level form, so don't do it here. The tag is never | |
496 | ;; for-effect. The body should have the same for-effect status | |
497 | ;; as the catch form itself, but that isn't handled properly yet. | |
498 | (cons fn | |
499 | (cons (byte-optimize-form (nth 1 form) nil) | |
500 | (cdr (cdr form))))) | |
501 | ||
8c26d7b3 RS |
502 | ((eq fn 'ignore) |
503 | ;; Don't treat the args to `ignore' as being | |
504 | ;; computed for effect. We want to avoid the warnings | |
505 | ;; that might occur if they were treated that way. | |
506 | ;; However, don't actually bother calling `ignore'. | |
507 | `(prog1 nil . ,(mapcar 'byte-optimize-form (cdr form)))) | |
508 | ||
1c393159 JB |
509 | ;; If optimization is on, this is the only place that macros are |
510 | ;; expanded. If optimization is off, then macroexpansion happens | |
511 | ;; in byte-compile-form. Otherwise, the macros are already expanded | |
512 | ;; by the time that is reached. | |
513 | ((not (eq form | |
514 | (setq form (macroexpand form | |
515 | byte-compile-macro-environment)))) | |
516 | (byte-optimize-form form for-effect)) | |
5428ee02 RS |
517 | |
518 | ;; Support compiler macros as in cl.el. | |
519 | ((and (fboundp 'compiler-macroexpand) | |
4f493b7c RS |
520 | (symbolp (car-safe form)) |
521 | (get (car-safe form) 'cl-compiler-macro) | |
5428ee02 | 522 | (not (eq form |
4cead7a2 RS |
523 | (with-no-warnings |
524 | (setq form (compiler-macroexpand form)))))) | |
5428ee02 | 525 | (byte-optimize-form form for-effect)) |
a1506d29 | 526 | |
1c393159 | 527 | ((not (symbolp fn)) |
5f11d42c PJ |
528 | (byte-compile-warn "`%s' is a malformed function" |
529 | (prin1-to-string fn)) | |
1c393159 JB |
530 | form) |
531 | ||
532 | ((and for-effect (setq tmp (get fn 'side-effect-free)) | |
533 | (or byte-compile-delete-errors | |
534 | (eq tmp 'error-free) | |
8c26d7b3 RS |
535 | ;; Detect the expansion of (pop foo). |
536 | ;; There is no need to compile the call to `car' there. | |
537 | (and (eq fn 'car) | |
538 | (eq (car-safe (cadr form)) 'prog1) | |
539 | (let ((var (cadr (cadr form))) | |
540 | (last (nth 2 (cadr form)))) | |
541 | (and (symbolp var) | |
542 | (null (nthcdr 3 (cadr form))) | |
543 | (eq (car-safe last) 'setq) | |
544 | (eq (cadr last) var) | |
545 | (eq (car-safe (nth 2 last)) 'cdr) | |
546 | (eq (cadr (nth 2 last)) var)))) | |
1c393159 | 547 | (progn |
1fbb84da CY |
548 | (byte-compile-warn "value returned from %s is unused" |
549 | (prin1-to-string form)) | |
1c393159 JB |
550 | nil))) |
551 | (byte-compile-log " %s called for effect; deleted" fn) | |
552 | ;; appending a nil here might not be necessary, but it can't hurt. | |
553 | (byte-optimize-form | |
554 | (cons 'progn (append (cdr form) '(nil))) t)) | |
a1506d29 | 555 | |
1c393159 JB |
556 | (t |
557 | ;; Otherwise, no args can be considered to be for-effect, | |
558 | ;; even if the called function is for-effect, because we | |
559 | ;; don't know anything about that function. | |
fb67ebdf CY |
560 | (let ((args (mapcar #'byte-optimize-form (cdr form)))) |
561 | (if (and (get fn 'pure) | |
562 | (byte-optimize-all-constp args)) | |
563 | (list 'quote (apply fn (mapcar #'eval args))) | |
564 | (cons fn args))))))) | |
565 | ||
566 | (defun byte-optimize-all-constp (list) | |
567 | "Non-nil iff all elements of LIST satisfy `byte-compile-constp'." | |
568 | (let ((constant t)) | |
569 | (while (and list constant) | |
570 | (unless (byte-compile-constp (car list)) | |
571 | (setq constant nil)) | |
572 | (setq list (cdr list))) | |
573 | constant)) | |
1c393159 JB |
574 | |
575 | (defun byte-optimize-form (form &optional for-effect) | |
576 | "The source-level pass of the optimizer." | |
577 | ;; | |
578 | ;; First, optimize all sub-forms of this one. | |
579 | (setq form (byte-optimize-form-code-walker form for-effect)) | |
580 | ;; | |
581 | ;; after optimizing all subforms, optimize this form until it doesn't | |
582 | ;; optimize any further. This means that some forms will be passed through | |
583 | ;; the optimizer many times, but that's necessary to make the for-effect | |
584 | ;; processing do as much as possible. | |
585 | ;; | |
586 | (let (opt new) | |
587 | (if (and (consp form) | |
588 | (symbolp (car form)) | |
589 | (or (and for-effect | |
590 | ;; we don't have any of these yet, but we might. | |
591 | (setq opt (get (car form) 'byte-for-effect-optimizer))) | |
592 | (setq opt (get (car form) 'byte-optimizer))) | |
593 | (not (eq form (setq new (funcall opt form))))) | |
594 | (progn | |
595 | ;; (if (equal form new) (error "bogus optimizer -- %s" opt)) | |
596 | (byte-compile-log " %s\t==>\t%s" form new) | |
597 | (setq new (byte-optimize-form new for-effect)) | |
598 | new) | |
599 | form))) | |
600 | ||
601 | ||
602 | (defun byte-optimize-body (forms all-for-effect) | |
603 | ;; optimize the cdr of a progn or implicit progn; all forms is a list of | |
604 | ;; forms, all but the last of which are optimized with the assumption that | |
605 | ;; they are being called for effect. the last is for-effect as well if | |
606 | ;; all-for-effect is true. returns a new list of forms. | |
607 | (let ((rest forms) | |
608 | (result nil) | |
609 | fe new) | |
610 | (while rest | |
611 | (setq fe (or all-for-effect (cdr rest))) | |
612 | (setq new (and (car rest) (byte-optimize-form (car rest) fe))) | |
613 | (if (or new (not fe)) | |
614 | (setq result (cons new result))) | |
615 | (setq rest (cdr rest))) | |
616 | (nreverse result))) | |
617 | ||
618 | \f | |
e856a453 SM |
619 | ;; some source-level optimizers |
620 | ;; | |
621 | ;; when writing optimizers, be VERY careful that the optimizer returns | |
622 | ;; something not EQ to its argument if and ONLY if it has made a change. | |
623 | ;; This implies that you cannot simply destructively modify the list; | |
624 | ;; you must return something not EQ to it if you make an optimization. | |
625 | ;; | |
626 | ;; It is now safe to optimize code such that it introduces new bindings. | |
1c393159 | 627 | |
eb8c3be9 | 628 | ;; I'd like this to be a defsubst, but let's not be self-referential... |
1c393159 JB |
629 | (defmacro byte-compile-trueconstp (form) |
630 | ;; Returns non-nil if FORM is a non-nil constant. | |
e1f0df62 DL |
631 | `(cond ((consp ,form) (eq (car ,form) 'quote)) |
632 | ((not (symbolp ,form))) | |
633 | ((eq ,form t)) | |
634 | ((keywordp ,form)))) | |
1c393159 | 635 | |
70e1dad8 | 636 | ;; If the function is being called with constant numeric args, |
a1506d29 | 637 | ;; evaluate as much as possible at compile-time. This optimizer |
70e1dad8 | 638 | ;; assumes that the function is associative, like + or *. |
1c393159 | 639 | (defun byte-optimize-associative-math (form) |
1c393159 JB |
640 | (let ((args nil) |
641 | (constants nil) | |
642 | (rest (cdr form))) | |
643 | (while rest | |
644 | (if (numberp (car rest)) | |
645 | (setq constants (cons (car rest) constants)) | |
646 | (setq args (cons (car rest) args))) | |
647 | (setq rest (cdr rest))) | |
648 | (if (cdr constants) | |
649 | (if args | |
650 | (list (car form) | |
651 | (apply (car form) constants) | |
652 | (if (cdr args) | |
653 | (cons (car form) (nreverse args)) | |
654 | (car args))) | |
655 | (apply (car form) constants)) | |
656 | form))) | |
657 | ||
70e1dad8 | 658 | ;; If the function is being called with constant numeric args, |
97e6527f KH |
659 | ;; evaluate as much as possible at compile-time. This optimizer |
660 | ;; assumes that the function satisfies | |
661 | ;; (op x1 x2 ... xn) == (op ...(op (op x1 x2) x3) ...xn) | |
662 | ;; like - and /. | |
1c393159 | 663 | (defun byte-optimize-nonassociative-math (form) |
1c393159 JB |
664 | (if (or (not (numberp (car (cdr form)))) |
665 | (not (numberp (car (cdr (cdr form)))))) | |
666 | form | |
667 | (let ((constant (car (cdr form))) | |
668 | (rest (cdr (cdr form)))) | |
669 | (while (numberp (car rest)) | |
670 | (setq constant (funcall (car form) constant (car rest)) | |
671 | rest (cdr rest))) | |
672 | (if rest | |
673 | (cons (car form) (cons constant rest)) | |
674 | constant)))) | |
675 | ||
676 | ;;(defun byte-optimize-associative-two-args-math (form) | |
677 | ;; (setq form (byte-optimize-associative-math form)) | |
678 | ;; (if (consp form) | |
679 | ;; (byte-optimize-two-args-left form) | |
680 | ;; form)) | |
681 | ||
682 | ;;(defun byte-optimize-nonassociative-two-args-math (form) | |
683 | ;; (setq form (byte-optimize-nonassociative-math form)) | |
684 | ;; (if (consp form) | |
685 | ;; (byte-optimize-two-args-right form) | |
686 | ;; form)) | |
687 | ||
97e6527f | 688 | (defun byte-optimize-approx-equal (x y) |
1fa68f21 | 689 | (<= (* (abs (- x y)) 100) (abs (+ x y)))) |
97e6527f KH |
690 | |
691 | ;; Collect all the constants from FORM, after the STARTth arg, | |
692 | ;; and apply FUN to them to make one argument at the end. | |
693 | ;; For functions that can handle floats, that optimization | |
694 | ;; can be incorrect because reordering can cause an overflow | |
695 | ;; that would otherwise be avoided by encountering an arg that is a float. | |
696 | ;; We avoid this problem by (1) not moving float constants and | |
697 | ;; (2) not moving anything if it would cause an overflow. | |
1c393159 JB |
698 | (defun byte-optimize-delay-constants-math (form start fun) |
699 | ;; Merge all FORM's constants from number START, call FUN on them | |
700 | ;; and put the result at the end. | |
97e6527f KH |
701 | (let ((rest (nthcdr (1- start) form)) |
702 | (orig form) | |
703 | ;; t means we must check for overflow. | |
704 | (overflow (memq fun '(+ *)))) | |
1c393159 | 705 | (while (cdr (setq rest (cdr rest))) |
97e6527f | 706 | (if (integerp (car rest)) |
1c393159 JB |
707 | (let (constants) |
708 | (setq form (copy-sequence form) | |
709 | rest (nthcdr (1- start) form)) | |
710 | (while (setq rest (cdr rest)) | |
97e6527f | 711 | (cond ((integerp (car rest)) |
1c393159 JB |
712 | (setq constants (cons (car rest) constants)) |
713 | (setcar rest nil)))) | |
97e6527f KH |
714 | ;; If necessary, check now for overflow |
715 | ;; that might be caused by reordering. | |
716 | (if (and overflow | |
717 | ;; We have overflow if the result of doing the arithmetic | |
718 | ;; on floats is not even close to the result | |
719 | ;; of doing it on integers. | |
720 | (not (byte-optimize-approx-equal | |
721 | (apply fun (mapcar 'float constants)) | |
722 | (float (apply fun constants))))) | |
723 | (setq form orig) | |
724 | (setq form (nconc (delq nil form) | |
725 | (list (apply fun (nreverse constants))))))))) | |
1c393159 JB |
726 | form)) |
727 | ||
728 | (defun byte-optimize-plus (form) | |
729 | (setq form (byte-optimize-delay-constants-math form 1 '+)) | |
730 | (if (memq 0 form) (setq form (delq 0 (copy-sequence form)))) | |
731 | ;;(setq form (byte-optimize-associative-two-args-math form)) | |
732 | (cond ((null (cdr form)) | |
733 | (condition-case () | |
734 | (eval form) | |
735 | (error form))) | |
e856a453 SM |
736 | ;;; It is not safe to delete the function entirely |
737 | ;;; (actually, it would be safe if we know the sole arg | |
738 | ;;; is not a marker). | |
739 | ;;; ((null (cdr (cdr form))) (nth 1 form)) | |
ea9d6371 RS |
740 | ((null (cddr form)) |
741 | (if (numberp (nth 1 form)) | |
742 | (nth 1 form) | |
743 | form)) | |
1fa68f21 RS |
744 | ((and (null (nthcdr 3 form)) |
745 | (or (memq (nth 1 form) '(1 -1)) | |
746 | (memq (nth 2 form) '(1 -1)))) | |
79d137ff | 747 | ;; Optimize (+ x 1) into (1+ x) and (+ x -1) into (1- x). |
1fa68f21 RS |
748 | (let ((integer |
749 | (if (memq (nth 1 form) '(1 -1)) | |
750 | (nth 1 form) | |
751 | (nth 2 form))) | |
752 | (other | |
753 | (if (memq (nth 1 form) '(1 -1)) | |
754 | (nth 2 form) | |
755 | (nth 1 form)))) | |
756 | (list (if (eq integer 1) '1+ '1-) | |
757 | other))) | |
1c393159 JB |
758 | (t form))) |
759 | ||
760 | (defun byte-optimize-minus (form) | |
761 | ;; Put constants at the end, except the last constant. | |
762 | (setq form (byte-optimize-delay-constants-math form 2 '+)) | |
763 | ;; Now only first and last element can be a number. | |
764 | (let ((last (car (reverse (nthcdr 3 form))))) | |
765 | (cond ((eq 0 last) | |
766 | ;; (- x y ... 0) --> (- x y ...) | |
767 | (setq form (copy-sequence form)) | |
768 | (setcdr (cdr (cdr form)) (delq 0 (nthcdr 3 form)))) | |
1fa68f21 RS |
769 | ((equal (nthcdr 2 form) '(1)) |
770 | (setq form (list '1- (nth 1 form)))) | |
771 | ((equal (nthcdr 2 form) '(-1)) | |
772 | (setq form (list '1+ (nth 1 form)))) | |
1c393159 JB |
773 | ;; If form is (- CONST foo... CONST), merge first and last. |
774 | ((and (numberp (nth 1 form)) | |
775 | (numberp last)) | |
776 | (setq form (nconc (list '- (- (nth 1 form) last) (nth 2 form)) | |
777 | (delq last (copy-sequence (nthcdr 3 form)))))))) | |
e856a453 SM |
778 | ;;; It is not safe to delete the function entirely |
779 | ;;; (actually, it would be safe if we know the sole arg | |
780 | ;;; is not a marker). | |
3315a6a3 RS |
781 | ;;; (if (eq (nth 2 form) 0) |
782 | ;;; (nth 1 form) ; (- x 0) --> x | |
1c393159 JB |
783 | (byte-optimize-predicate |
784 | (if (and (null (cdr (cdr (cdr form)))) | |
785 | (eq (nth 1 form) 0)) ; (- 0 x) --> (- x) | |
786 | (cons (car form) (cdr (cdr form))) | |
3315a6a3 RS |
787 | form)) |
788 | ;;; ) | |
789 | ) | |
1c393159 JB |
790 | |
791 | (defun byte-optimize-multiply (form) | |
792 | (setq form (byte-optimize-delay-constants-math form 1 '*)) | |
793 | ;; If there is a constant in FORM, it is now the last element. | |
794 | (cond ((null (cdr form)) 1) | |
e856a453 SM |
795 | ;;; It is not safe to delete the function entirely |
796 | ;;; (actually, it would be safe if we know the sole arg | |
797 | ;;; is not a marker or if it appears in other arithmetic). | |
3315a6a3 | 798 | ;;; ((null (cdr (cdr form))) (nth 1 form)) |
1c393159 | 799 | ((let ((last (car (reverse form)))) |
97e6527f | 800 | (cond ((eq 0 last) (cons 'progn (cdr form))) |
1c393159 JB |
801 | ((eq 1 last) (delq 1 (copy-sequence form))) |
802 | ((eq -1 last) (list '- (delq -1 (copy-sequence form)))) | |
803 | ((and (eq 2 last) | |
804 | (memq t (mapcar 'symbolp (cdr form)))) | |
805 | (prog1 (setq form (delq 2 (copy-sequence form))) | |
806 | (while (not (symbolp (car (setq form (cdr form)))))) | |
807 | (setcar form (list '+ (car form) (car form))))) | |
808 | (form)))))) | |
809 | ||
810 | (defsubst byte-compile-butlast (form) | |
811 | (nreverse (cdr (reverse form)))) | |
812 | ||
813 | (defun byte-optimize-divide (form) | |
814 | (setq form (byte-optimize-delay-constants-math form 2 '*)) | |
815 | (let ((last (car (reverse (cdr (cdr form)))))) | |
816 | (if (numberp last) | |
199dd758 | 817 | (cond ((= (length form) 3) |
97e6527f KH |
818 | (if (and (numberp (nth 1 form)) |
819 | (not (zerop last)) | |
820 | (condition-case nil | |
821 | (/ (nth 1 form) last) | |
822 | (error nil))) | |
823 | (setq form (list 'progn (/ (nth 1 form) last))))) | |
199dd758 | 824 | ((= last 1) |
1c393159 JB |
825 | (setq form (byte-compile-butlast form))) |
826 | ((numberp (nth 1 form)) | |
827 | (setq form (cons (car form) | |
828 | (cons (/ (nth 1 form) last) | |
829 | (byte-compile-butlast (cdr (cdr form))))) | |
830 | last nil)))) | |
a1506d29 | 831 | (cond |
3315a6a3 RS |
832 | ;;; ((null (cdr (cdr form))) |
833 | ;;; (nth 1 form)) | |
1c393159 JB |
834 | ((eq (nth 1 form) 0) |
835 | (append '(progn) (cdr (cdr form)) '(0))) | |
836 | ((eq last -1) | |
837 | (list '- (if (nthcdr 3 form) | |
838 | (byte-compile-butlast form) | |
839 | (nth 1 form)))) | |
840 | (form)))) | |
841 | ||
842 | (defun byte-optimize-logmumble (form) | |
843 | (setq form (byte-optimize-delay-constants-math form 1 (car form))) | |
844 | (byte-optimize-predicate | |
845 | (cond ((memq 0 form) | |
846 | (setq form (if (eq (car form) 'logand) | |
847 | (cons 'progn (cdr form)) | |
848 | (delq 0 (copy-sequence form))))) | |
849 | ((and (eq (car-safe form) 'logior) | |
850 | (memq -1 form)) | |
97e6527f | 851 | (cons 'progn (cdr form))) |
1c393159 JB |
852 | (form)))) |
853 | ||
854 | ||
855 | (defun byte-optimize-binary-predicate (form) | |
856 | (if (byte-compile-constp (nth 1 form)) | |
857 | (if (byte-compile-constp (nth 2 form)) | |
858 | (condition-case () | |
859 | (list 'quote (eval form)) | |
860 | (error form)) | |
861 | ;; This can enable some lapcode optimizations. | |
862 | (list (car form) (nth 2 form) (nth 1 form))) | |
863 | form)) | |
864 | ||
865 | (defun byte-optimize-predicate (form) | |
866 | (let ((ok t) | |
867 | (rest (cdr form))) | |
868 | (while (and rest ok) | |
869 | (setq ok (byte-compile-constp (car rest)) | |
870 | rest (cdr rest))) | |
871 | (if ok | |
872 | (condition-case () | |
873 | (list 'quote (eval form)) | |
874 | (error form)) | |
875 | form))) | |
876 | ||
877 | (defun byte-optimize-identity (form) | |
878 | (if (and (cdr form) (null (cdr (cdr form)))) | |
879 | (nth 1 form) | |
244bbdc5 | 880 | (byte-compile-warn "identity called with %d arg%s, but requires 1" |
1c393159 JB |
881 | (length (cdr form)) |
882 | (if (= 1 (length (cdr form))) "" "s")) | |
883 | form)) | |
884 | ||
885 | (put 'identity 'byte-optimizer 'byte-optimize-identity) | |
886 | ||
887 | (put '+ 'byte-optimizer 'byte-optimize-plus) | |
888 | (put '* 'byte-optimizer 'byte-optimize-multiply) | |
889 | (put '- 'byte-optimizer 'byte-optimize-minus) | |
890 | (put '/ 'byte-optimizer 'byte-optimize-divide) | |
891 | (put 'max 'byte-optimizer 'byte-optimize-associative-math) | |
892 | (put 'min 'byte-optimizer 'byte-optimize-associative-math) | |
893 | ||
894 | (put '= 'byte-optimizer 'byte-optimize-binary-predicate) | |
895 | (put 'eq 'byte-optimizer 'byte-optimize-binary-predicate) | |
1c393159 JB |
896 | (put 'equal 'byte-optimizer 'byte-optimize-binary-predicate) |
897 | (put 'string= 'byte-optimizer 'byte-optimize-binary-predicate) | |
898 | (put 'string-equal 'byte-optimizer 'byte-optimize-binary-predicate) | |
899 | ||
900 | (put '< 'byte-optimizer 'byte-optimize-predicate) | |
901 | (put '> 'byte-optimizer 'byte-optimize-predicate) | |
902 | (put '<= 'byte-optimizer 'byte-optimize-predicate) | |
903 | (put '>= 'byte-optimizer 'byte-optimize-predicate) | |
904 | (put '1+ 'byte-optimizer 'byte-optimize-predicate) | |
905 | (put '1- 'byte-optimizer 'byte-optimize-predicate) | |
906 | (put 'not 'byte-optimizer 'byte-optimize-predicate) | |
907 | (put 'null 'byte-optimizer 'byte-optimize-predicate) | |
908 | (put 'memq 'byte-optimizer 'byte-optimize-predicate) | |
909 | (put 'consp 'byte-optimizer 'byte-optimize-predicate) | |
910 | (put 'listp 'byte-optimizer 'byte-optimize-predicate) | |
911 | (put 'symbolp 'byte-optimizer 'byte-optimize-predicate) | |
912 | (put 'stringp 'byte-optimizer 'byte-optimize-predicate) | |
913 | (put 'string< 'byte-optimizer 'byte-optimize-predicate) | |
914 | (put 'string-lessp 'byte-optimizer 'byte-optimize-predicate) | |
915 | ||
916 | (put 'logand 'byte-optimizer 'byte-optimize-logmumble) | |
917 | (put 'logior 'byte-optimizer 'byte-optimize-logmumble) | |
918 | (put 'logxor 'byte-optimizer 'byte-optimize-logmumble) | |
919 | (put 'lognot 'byte-optimizer 'byte-optimize-predicate) | |
920 | ||
921 | (put 'car 'byte-optimizer 'byte-optimize-predicate) | |
922 | (put 'cdr 'byte-optimizer 'byte-optimize-predicate) | |
923 | (put 'car-safe 'byte-optimizer 'byte-optimize-predicate) | |
924 | (put 'cdr-safe 'byte-optimizer 'byte-optimize-predicate) | |
925 | ||
926 | ||
a1506d29 | 927 | ;; I'm not convinced that this is necessary. Doesn't the optimizer loop |
1c393159 JB |
928 | ;; take care of this? - Jamie |
929 | ;; I think this may some times be necessary to reduce ie (quote 5) to 5, | |
eb8c3be9 | 930 | ;; so arithmetic optimizers recognize the numeric constant. - Hallvard |
1c393159 JB |
931 | (put 'quote 'byte-optimizer 'byte-optimize-quote) |
932 | (defun byte-optimize-quote (form) | |
933 | (if (or (consp (nth 1 form)) | |
934 | (and (symbolp (nth 1 form)) | |
e1f0df62 | 935 | (not (byte-compile-const-symbol-p form)))) |
1c393159 JB |
936 | form |
937 | (nth 1 form))) | |
938 | ||
939 | (defun byte-optimize-zerop (form) | |
940 | (cond ((numberp (nth 1 form)) | |
941 | (eval form)) | |
942 | (byte-compile-delete-errors | |
943 | (list '= (nth 1 form) 0)) | |
944 | (form))) | |
945 | ||
946 | (put 'zerop 'byte-optimizer 'byte-optimize-zerop) | |
947 | ||
948 | (defun byte-optimize-and (form) | |
949 | ;; Simplify if less than 2 args. | |
950 | ;; if there is a literal nil in the args to `and', throw it and following | |
951 | ;; forms away, and surround the `and' with (progn ... nil). | |
952 | (cond ((null (cdr form))) | |
953 | ((memq nil form) | |
954 | (list 'progn | |
955 | (byte-optimize-and | |
956 | (prog1 (setq form (copy-sequence form)) | |
957 | (while (nth 1 form) | |
958 | (setq form (cdr form))) | |
959 | (setcdr form nil))) | |
960 | nil)) | |
961 | ((null (cdr (cdr form))) | |
962 | (nth 1 form)) | |
963 | ((byte-optimize-predicate form)))) | |
964 | ||
965 | (defun byte-optimize-or (form) | |
966 | ;; Throw away nil's, and simplify if less than 2 args. | |
967 | ;; If there is a literal non-nil constant in the args to `or', throw away all | |
968 | ;; following forms. | |
969 | (if (memq nil form) | |
970 | (setq form (delq nil (copy-sequence form)))) | |
971 | (let ((rest form)) | |
972 | (while (cdr (setq rest (cdr rest))) | |
973 | (if (byte-compile-trueconstp (car rest)) | |
974 | (setq form (copy-sequence form) | |
975 | rest (setcdr (memq (car rest) form) nil)))) | |
976 | (if (cdr (cdr form)) | |
977 | (byte-optimize-predicate form) | |
978 | (nth 1 form)))) | |
979 | ||
980 | (defun byte-optimize-cond (form) | |
981 | ;; if any clauses have a literal nil as their test, throw them away. | |
982 | ;; if any clause has a literal non-nil constant as its test, throw | |
983 | ;; away all following clauses. | |
984 | (let (rest) | |
985 | ;; This must be first, to reduce (cond (t ...) (nil)) to (progn t ...) | |
986 | (while (setq rest (assq nil (cdr form))) | |
987 | (setq form (delq rest (copy-sequence form)))) | |
988 | (if (memq nil (cdr form)) | |
989 | (setq form (delq nil (copy-sequence form)))) | |
990 | (setq rest form) | |
991 | (while (setq rest (cdr rest)) | |
992 | (cond ((byte-compile-trueconstp (car-safe (car rest))) | |
993 | (cond ((eq rest (cdr form)) | |
994 | (setq form | |
995 | (if (cdr (car rest)) | |
996 | (if (cdr (cdr (car rest))) | |
997 | (cons 'progn (cdr (car rest))) | |
998 | (nth 1 (car rest))) | |
999 | (car (car rest))))) | |
1000 | ((cdr rest) | |
1001 | (setq form (copy-sequence form)) | |
1002 | (setcdr (memq (car rest) form) nil))) | |
1003 | (setq rest nil))))) | |
1004 | ;; | |
1005 | ;; Turn (cond (( <x> )) ... ) into (or <x> (cond ... )) | |
1006 | (if (eq 'cond (car-safe form)) | |
1007 | (let ((clauses (cdr form))) | |
1008 | (if (and (consp (car clauses)) | |
1009 | (null (cdr (car clauses)))) | |
1010 | (list 'or (car (car clauses)) | |
1011 | (byte-optimize-cond | |
1012 | (cons (car form) (cdr (cdr form))))) | |
1013 | form)) | |
1014 | form)) | |
1015 | ||
1016 | (defun byte-optimize-if (form) | |
1017 | ;; (if <true-constant> <then> <else...>) ==> <then> | |
1018 | ;; (if <false-constant> <then> <else...>) ==> (progn <else...>) | |
1019 | ;; (if <test> nil <else...>) ==> (if (not <test>) (progn <else...>)) | |
1020 | ;; (if <test> <then> nil) ==> (if <test> <then>) | |
1021 | (let ((clause (nth 1 form))) | |
1022 | (cond ((byte-compile-trueconstp clause) | |
1023 | (nth 2 form)) | |
1024 | ((null clause) | |
1025 | (if (nthcdr 4 form) | |
1026 | (cons 'progn (nthcdr 3 form)) | |
1027 | (nth 3 form))) | |
1028 | ((nth 2 form) | |
1029 | (if (equal '(nil) (nthcdr 3 form)) | |
1030 | (list 'if clause (nth 2 form)) | |
1031 | form)) | |
1032 | ((or (nth 3 form) (nthcdr 4 form)) | |
97e6527f KH |
1033 | (list 'if |
1034 | ;; Don't make a double negative; | |
1035 | ;; instead, take away the one that is there. | |
1036 | (if (and (consp clause) (memq (car clause) '(not null)) | |
1037 | (= (length clause) 2)) ; (not xxxx) or (not (xxxx)) | |
1038 | (nth 1 clause) | |
1039 | (list 'not clause)) | |
1c393159 JB |
1040 | (if (nthcdr 4 form) |
1041 | (cons 'progn (nthcdr 3 form)) | |
1042 | (nth 3 form)))) | |
1043 | (t | |
1044 | (list 'progn clause nil))))) | |
1045 | ||
1046 | (defun byte-optimize-while (form) | |
aefd695a | 1047 | (when (< (length form) 2) |
244bbdc5 | 1048 | (byte-compile-warn "too few arguments for `while'")) |
1c393159 JB |
1049 | (if (nth 1 form) |
1050 | form)) | |
1051 | ||
1052 | (put 'and 'byte-optimizer 'byte-optimize-and) | |
1053 | (put 'or 'byte-optimizer 'byte-optimize-or) | |
1054 | (put 'cond 'byte-optimizer 'byte-optimize-cond) | |
1055 | (put 'if 'byte-optimizer 'byte-optimize-if) | |
1056 | (put 'while 'byte-optimizer 'byte-optimize-while) | |
1057 | ||
1058 | ;; byte-compile-negation-optimizer lives in bytecomp.el | |
1059 | (put '/= 'byte-optimizer 'byte-compile-negation-optimizer) | |
1060 | (put 'atom 'byte-optimizer 'byte-compile-negation-optimizer) | |
1061 | (put 'nlistp 'byte-optimizer 'byte-compile-negation-optimizer) | |
1062 | ||
1063 | ||
1064 | (defun byte-optimize-funcall (form) | |
72d8b544 SM |
1065 | ;; (funcall (lambda ...) ...) ==> ((lambda ...) ...) |
1066 | ;; (funcall foo ...) ==> (foo ...) | |
1c393159 JB |
1067 | (let ((fn (nth 1 form))) |
1068 | (if (memq (car-safe fn) '(quote function)) | |
1069 | (cons (nth 1 fn) (cdr (cdr form))) | |
1070 | form))) | |
1071 | ||
1072 | (defun byte-optimize-apply (form) | |
1073 | ;; If the last arg is a literal constant, turn this into a funcall. | |
1074 | ;; The funcall optimizer can then transform (funcall 'foo ...) -> (foo ...). | |
1075 | (let ((fn (nth 1 form)) | |
1076 | (last (nth (1- (length form)) form))) ; I think this really is fastest | |
1077 | (or (if (or (null last) | |
1078 | (eq (car-safe last) 'quote)) | |
1079 | (if (listp (nth 1 last)) | |
1080 | (let ((butlast (nreverse (cdr (reverse (cdr (cdr form))))))) | |
7e1dae73 | 1081 | (nconc (list 'funcall fn) butlast |
72d8b544 | 1082 | (mapcar (lambda (x) (list 'quote x)) (nth 1 last)))) |
1c393159 | 1083 | (byte-compile-warn |
244bbdc5 | 1084 | "last arg to apply can't be a literal atom: `%s'" |
1c393159 JB |
1085 | (prin1-to-string last)) |
1086 | nil)) | |
1087 | form))) | |
1088 | ||
1089 | (put 'funcall 'byte-optimizer 'byte-optimize-funcall) | |
1090 | (put 'apply 'byte-optimizer 'byte-optimize-apply) | |
1091 | ||
1092 | ||
1093 | (put 'let 'byte-optimizer 'byte-optimize-letX) | |
1094 | (put 'let* 'byte-optimizer 'byte-optimize-letX) | |
1095 | (defun byte-optimize-letX (form) | |
1096 | (cond ((null (nth 1 form)) | |
1097 | ;; No bindings | |
1098 | (cons 'progn (cdr (cdr form)))) | |
1099 | ((or (nth 2 form) (nthcdr 3 form)) | |
1100 | form) | |
1101 | ;; The body is nil | |
1102 | ((eq (car form) 'let) | |
5d265171 RS |
1103 | (append '(progn) (mapcar 'car-safe (mapcar 'cdr-safe (nth 1 form))) |
1104 | '(nil))) | |
1c393159 JB |
1105 | (t |
1106 | (let ((binds (reverse (nth 1 form)))) | |
1107 | (list 'let* (reverse (cdr binds)) (nth 1 (car binds)) nil))))) | |
1108 | ||
1109 | ||
1110 | (put 'nth 'byte-optimizer 'byte-optimize-nth) | |
1111 | (defun byte-optimize-nth (form) | |
56cfa244 DL |
1112 | (if (= (safe-length form) 3) |
1113 | (if (memq (nth 1 form) '(0 1)) | |
1114 | (list 'car (if (zerop (nth 1 form)) | |
1115 | (nth 2 form) | |
1116 | (list 'cdr (nth 2 form)))) | |
1117 | (byte-optimize-predicate form)) | |
1118 | form)) | |
1c393159 JB |
1119 | |
1120 | (put 'nthcdr 'byte-optimizer 'byte-optimize-nthcdr) | |
1121 | (defun byte-optimize-nthcdr (form) | |
56cfa244 DL |
1122 | (if (= (safe-length form) 3) |
1123 | (if (memq (nth 1 form) '(0 1 2)) | |
1124 | (let ((count (nth 1 form))) | |
1125 | (setq form (nth 2 form)) | |
1126 | (while (>= (setq count (1- count)) 0) | |
1127 | (setq form (list 'cdr form))) | |
1128 | form) | |
1129 | (byte-optimize-predicate form)) | |
1130 | form)) | |
79d137ff | 1131 | |
e5c230f4 DL |
1132 | ;; Fixme: delete-char -> delete-region (byte-coded) |
1133 | ;; optimize string-as-unibyte, string-as-multibyte, string-make-unibyte, | |
1134 | ;; string-make-multibyte for constant args. | |
1135 | ||
1136 | (put 'featurep 'byte-optimizer 'byte-optimize-featurep) | |
1137 | (defun byte-optimize-featurep (form) | |
e8f3c355 SM |
1138 | ;; Emacs-21's byte-code doesn't run under XEmacs anyway, so we can |
1139 | ;; safely optimize away this test. | |
e5c230f4 DL |
1140 | (if (equal '((quote xemacs)) (cdr-safe form)) |
1141 | nil | |
1142 | form)) | |
66ff2893 SM |
1143 | |
1144 | (put 'set 'byte-optimizer 'byte-optimize-set) | |
1145 | (defun byte-optimize-set (form) | |
1146 | (let ((var (car-safe (cdr-safe form)))) | |
1147 | (cond | |
1148 | ((and (eq (car-safe var) 'quote) (consp (cdr var))) | |
e64e9e6a | 1149 | `(setq ,(cadr var) ,@(cddr form))) |
66ff2893 SM |
1150 | ((and (eq (car-safe var) 'make-local-variable) |
1151 | (eq (car-safe (setq var (car-safe (cdr var)))) 'quote) | |
1152 | (consp (cdr var))) | |
1153 | `(progn ,(cadr form) (setq ,(cadr var) ,@(cddr form)))) | |
1154 | (t form)))) | |
1c393159 | 1155 | \f |
e856a453 SM |
1156 | ;; enumerating those functions which need not be called if the returned |
1157 | ;; value is not used. That is, something like | |
1158 | ;; (progn (list (something-with-side-effects) (yow)) | |
1159 | ;; (foo)) | |
1160 | ;; may safely be turned into | |
1161 | ;; (progn (progn (something-with-side-effects) (yow)) | |
1162 | ;; (foo)) | |
1163 | ;; Further optimizations will turn (progn (list 1 2 3) 'foo) into 'foo. | |
1164 | ||
1165 | ;; Some of these functions have the side effect of allocating memory | |
1166 | ;; and it would be incorrect to replace two calls with one. | |
1167 | ;; But we don't try to do those kinds of optimizations, | |
1168 | ;; so it is safe to list such functions here. | |
1169 | ;; Some of these functions return values that depend on environment | |
1170 | ;; state, so that constant folding them would be wrong, | |
1171 | ;; but we don't do constant folding based on this list. | |
1172 | ||
1173 | ;; However, at present the only optimization we normally do | |
1174 | ;; is delete calls that need not occur, and we only do that | |
1175 | ;; with the error-free functions. | |
1176 | ||
1177 | ;; I wonder if I missed any :-\) | |
1c393159 | 1178 | (let ((side-effect-free-fns |
c20a77cc RS |
1179 | '(% * + - / /= 1+ 1- < <= = > >= abs acos append aref ash asin atan |
1180 | assoc assq | |
1181 | boundp buffer-file-name buffer-local-variables buffer-modified-p | |
1fc9ee97 | 1182 | buffer-substring byte-code-function-p |
049a65a3 | 1183 | capitalize car-less-than-car car cdr ceiling char-after char-before |
1fc9ee97 RS |
1184 | char-equal char-to-string char-width |
1185 | compare-strings concat coordinates-in-window-p | |
1186 | copy-alist copy-sequence copy-marker cos count-lines | |
1187 | decode-time default-boundp default-value documentation downcase | |
1188 | elt exp expt encode-time error-message-string | |
1189 | fboundp fceiling featurep ffloor | |
1c393159 JB |
1190 | file-directory-p file-exists-p file-locked-p file-name-absolute-p |
1191 | file-newer-than-file-p file-readable-p file-symlink-p file-writable-p | |
1fc9ee97 RS |
1192 | float float-time floor format format-time-string frame-visible-p |
1193 | fround ftruncate | |
2412aadb DL |
1194 | get gethash get-buffer get-buffer-window getenv get-file-buffer |
1195 | hash-table-count | |
1fc9ee97 | 1196 | int-to-string intern-soft |
f34bba69 | 1197 | keymap-parent |
e1f0df62 DL |
1198 | length local-variable-if-set-p local-variable-p log log10 logand |
1199 | logb logior lognot logxor lsh | |
1fc9ee97 | 1200 | make-list make-string make-symbol |
d9881cf1 | 1201 | marker-buffer max member memq min mod multibyte-char-to-unibyte |
c20a77cc | 1202 | next-window nth nthcdr number-to-string |
1fc9ee97 RS |
1203 | parse-colon-path plist-get plist-member |
1204 | prefix-numeric-value previous-window prin1-to-string propertize | |
1205 | radians-to-degrees rassq rassoc read-from-string regexp-quote | |
1206 | region-beginning region-end reverse round | |
049a65a3 | 1207 | sin sqrt string string< string= string-equal string-lessp string-to-char |
1fc9ee97 | 1208 | string-to-int string-to-number substring sxhash symbol-function |
d9881cf1 DL |
1209 | symbol-name symbol-plist symbol-value string-make-unibyte |
1210 | string-make-multibyte string-as-multibyte string-as-unibyte | |
1fc9ee97 RS |
1211 | tan truncate |
1212 | unibyte-char-to-multibyte upcase user-full-name | |
1213 | user-login-name user-original-login-name user-variable-p | |
1214 | vconcat | |
c20a77cc RS |
1215 | window-buffer window-dedicated-p window-edges window-height |
1216 | window-hscroll window-minibuffer-p window-width | |
1c393159 | 1217 | zerop)) |
1c393159 | 1218 | (side-effect-and-error-free-fns |
c20a77cc | 1219 | '(arrayp atom |
a1506d29 | 1220 | bobp bolp bool-vector-p |
1fc9ee97 | 1221 | buffer-end buffer-list buffer-size buffer-string bufferp |
c20a77cc | 1222 | car-safe case-table-p cdr-safe char-or-string-p commandp cons consp |
f34bba69 | 1223 | current-buffer current-global-map current-indentation |
1fc9ee97 RS |
1224 | current-local-map current-minor-mode-maps current-time |
1225 | current-time-string current-time-zone | |
1226 | eobp eolp eq equal eventp | |
049a65a3 | 1227 | floatp following-char framep |
c20a77cc | 1228 | get-largest-window get-lru-window |
2412aadb | 1229 | hash-table-p |
c20a77cc RS |
1230 | identity ignore integerp integer-or-marker-p interactive-p |
1231 | invocation-directory invocation-name | |
f34bba69 DL |
1232 | keymapp |
1233 | line-beginning-position line-end-position list listp | |
c20a77cc RS |
1234 | make-marker mark mark-marker markerp memory-limit minibuffer-window |
1235 | mouse-movement-p | |
1236 | natnump nlistp not null number-or-marker-p numberp | |
1237 | one-window-p overlayp | |
049a65a3 | 1238 | point point-marker point-min point-max preceding-char processp |
f34bba69 | 1239 | recent-keys recursion-depth |
1fc9ee97 RS |
1240 | safe-length selected-frame selected-window sequencep |
1241 | standard-case-table standard-syntax-table stringp subrp symbolp | |
1242 | syntax-table syntax-table-p | |
f34bba69 DL |
1243 | this-command-keys this-command-keys-vector this-single-command-keys |
1244 | this-single-command-raw-keys | |
c20a77cc | 1245 | user-real-login-name user-real-uid user-uid |
f34bba69 | 1246 | vector vectorp visible-frame-list |
1fc9ee97 | 1247 | wholenump window-configuration-p window-live-p windowp))) |
1c393159 JB |
1248 | (while side-effect-free-fns |
1249 | (put (car side-effect-free-fns) 'side-effect-free t) | |
1250 | (setq side-effect-free-fns (cdr side-effect-free-fns))) | |
1251 | (while side-effect-and-error-free-fns | |
1252 | (put (car side-effect-and-error-free-fns) 'side-effect-free 'error-free) | |
1253 | (setq side-effect-and-error-free-fns (cdr side-effect-and-error-free-fns))) | |
1254 | nil) | |
1255 | ||
fb67ebdf CY |
1256 | \f |
1257 | ;; pure functions are side-effect free functions whose values depend | |
1258 | ;; only on their arguments. For these functions, calls with constant | |
1259 | ;; arguments can be evaluated at compile time. This may shift run time | |
1260 | ;; errors to compile time. | |
1261 | ||
1262 | (let ((pure-fns | |
1263 | '(concat symbol-name regexp-opt regexp-quote string-to-syntax))) | |
1264 | (while pure-fns | |
1265 | (put (car pure-fns) 'pure t) | |
1266 | (setq pure-fns (cdr pure-fns))) | |
1267 | nil) | |
1c393159 JB |
1268 | |
1269 | (defun byte-compile-splice-in-already-compiled-code (form) | |
1270 | ;; form is (byte-code "..." [...] n) | |
1271 | (if (not (memq byte-optimize '(t lap))) | |
1272 | (byte-compile-normal-call form) | |
1273 | (byte-inline-lapcode | |
1274 | (byte-decompile-bytecode-1 (nth 1 form) (nth 2 form) t)) | |
1275 | (setq byte-compile-maxdepth (max (+ byte-compile-depth (nth 3 form)) | |
1276 | byte-compile-maxdepth)) | |
1277 | (setq byte-compile-depth (1+ byte-compile-depth)))) | |
1278 | ||
1279 | (put 'byte-code 'byte-compile 'byte-compile-splice-in-already-compiled-code) | |
1280 | ||
1281 | \f | |
1282 | (defconst byte-constref-ops | |
1283 | '(byte-constant byte-constant2 byte-varref byte-varset byte-varbind)) | |
1284 | ||
e856a453 SM |
1285 | ;; This function extracts the bitfields from variable-length opcodes. |
1286 | ;; Originally defined in disass.el (which no longer uses it.) | |
1c393159 JB |
1287 | |
1288 | (defun disassemble-offset () | |
1289 | "Don't call this!" | |
1290 | ;; fetch and return the offset for the current opcode. | |
f0529b5b | 1291 | ;; return nil if this opcode has no offset |
1c393159 JB |
1292 | ;; OP, PTR and BYTES are used and set dynamically |
1293 | (defvar op) | |
1294 | (defvar ptr) | |
1295 | (defvar bytes) | |
1296 | (cond ((< op byte-nth) | |
1297 | (let ((tem (logand op 7))) | |
1298 | (setq op (logand op 248)) | |
1299 | (cond ((eq tem 6) | |
1300 | (setq ptr (1+ ptr)) ;offset in next byte | |
1301 | (aref bytes ptr)) | |
1302 | ((eq tem 7) | |
1303 | (setq ptr (1+ ptr)) ;offset in next 2 bytes | |
1304 | (+ (aref bytes ptr) | |
1305 | (progn (setq ptr (1+ ptr)) | |
1306 | (lsh (aref bytes ptr) 8)))) | |
1307 | (t tem)))) ;offset was in opcode | |
1308 | ((>= op byte-constant) | |
1309 | (prog1 (- op byte-constant) ;offset in opcode | |
1310 | (setq op byte-constant))) | |
1311 | ((and (>= op byte-constant2) | |
1312 | (<= op byte-goto-if-not-nil-else-pop)) | |
1313 | (setq ptr (1+ ptr)) ;offset in next 2 bytes | |
1314 | (+ (aref bytes ptr) | |
1315 | (progn (setq ptr (1+ ptr)) | |
1316 | (lsh (aref bytes ptr) 8)))) | |
3eac9910 | 1317 | ((and (>= op byte-listN) |
1c393159 JB |
1318 | (<= op byte-insertN)) |
1319 | (setq ptr (1+ ptr)) ;offset in next byte | |
1320 | (aref bytes ptr)))) | |
1321 | ||
1322 | ||
e856a453 SM |
1323 | ;; This de-compiler is used for inline expansion of compiled functions, |
1324 | ;; and by the disassembler. | |
1325 | ;; | |
1326 | ;; This list contains numbers, which are pc values, | |
1327 | ;; before each instruction. | |
1c393159 | 1328 | (defun byte-decompile-bytecode (bytes constvec) |
eb8c3be9 | 1329 | "Turns BYTECODE into lapcode, referring to CONSTVEC." |
1c393159 JB |
1330 | (let ((byte-compile-constants nil) |
1331 | (byte-compile-variables nil) | |
1332 | (byte-compile-tag-number 0)) | |
1333 | (byte-decompile-bytecode-1 bytes constvec))) | |
1334 | ||
70e1dad8 RS |
1335 | ;; As byte-decompile-bytecode, but updates |
1336 | ;; byte-compile-{constants, variables, tag-number}. | |
cffcfe66 | 1337 | ;; If MAKE-SPLICEABLE is true, then `return' opcodes are replaced |
70e1dad8 | 1338 | ;; with `goto's destined for the end of the code. |
cffcfe66 RS |
1339 | ;; That is for use by the compiler. |
1340 | ;; If MAKE-SPLICEABLE is nil, we are being called for the disassembler. | |
1341 | ;; In that case, we put a pc value into the list | |
1342 | ;; before each insn (or its label). | |
1343 | (defun byte-decompile-bytecode-1 (bytes constvec &optional make-spliceable) | |
1c393159 | 1344 | (let ((length (length bytes)) |
08d72d13 | 1345 | (ptr 0) optr tags op offset |
1c393159 | 1346 | lap tmp |
08d72d13 | 1347 | endtag) |
1c393159 | 1348 | (while (not (= ptr length)) |
cffcfe66 RS |
1349 | (or make-spliceable |
1350 | (setq lap (cons ptr lap))) | |
1c393159 JB |
1351 | (setq op (aref bytes ptr) |
1352 | optr ptr | |
1353 | offset (disassemble-offset)) ; this does dynamic-scope magic | |
1354 | (setq op (aref byte-code-vector op)) | |
3eac9910 | 1355 | (cond ((memq op byte-goto-ops) |
1c393159 JB |
1356 | ;; it's a pc |
1357 | (setq offset | |
1358 | (cdr (or (assq offset tags) | |
1359 | (car (setq tags | |
1360 | (cons (cons offset | |
1361 | (byte-compile-make-tag)) | |
1362 | tags))))))) | |
1363 | ((cond ((eq op 'byte-constant2) (setq op 'byte-constant) t) | |
1364 | ((memq op byte-constref-ops))) | |
6ebe9f82 RS |
1365 | (setq tmp (if (>= offset (length constvec)) |
1366 | (list 'out-of-range offset) | |
1367 | (aref constvec offset)) | |
1c393159 JB |
1368 | offset (if (eq op 'byte-constant) |
1369 | (byte-compile-get-constant tmp) | |
1370 | (or (assq tmp byte-compile-variables) | |
1371 | (car (setq byte-compile-variables | |
1372 | (cons (list tmp) | |
1373 | byte-compile-variables))))))) | |
cffcfe66 | 1374 | ((and make-spliceable |
1c393159 JB |
1375 | (eq op 'byte-return)) |
1376 | (if (= ptr (1- length)) | |
1377 | (setq op nil) | |
1378 | (setq offset (or endtag (setq endtag (byte-compile-make-tag))) | |
1379 | op 'byte-goto)))) | |
1380 | ;; lap = ( [ (pc . (op . arg)) ]* ) | |
1381 | (setq lap (cons (cons optr (cons op (or offset 0))) | |
1382 | lap)) | |
1383 | (setq ptr (1+ ptr))) | |
1384 | ;; take off the dummy nil op that we replaced a trailing "return" with. | |
1385 | (let ((rest lap)) | |
1386 | (while rest | |
41cf13b9 RS |
1387 | (cond ((numberp (car rest))) |
1388 | ((setq tmp (assq (car (car rest)) tags)) | |
1c393159 JB |
1389 | ;; this addr is jumped to |
1390 | (setcdr rest (cons (cons nil (cdr tmp)) | |
1391 | (cdr rest))) | |
1392 | (setq tags (delq tmp tags)) | |
1393 | (setq rest (cdr rest)))) | |
1394 | (setq rest (cdr rest)))) | |
1395 | (if tags (error "optimizer error: missed tags %s" tags)) | |
1396 | (if (null (car (cdr (car lap)))) | |
1397 | (setq lap (cdr lap))) | |
1398 | (if endtag | |
1399 | (setq lap (cons (cons nil endtag) lap))) | |
1400 | ;; remove addrs, lap = ( [ (op . arg) | (TAG tagno) ]* ) | |
41cf13b9 RS |
1401 | (mapcar (function (lambda (elt) |
1402 | (if (numberp elt) | |
1403 | elt | |
1404 | (cdr elt)))) | |
1405 | (nreverse lap)))) | |
1c393159 JB |
1406 | |
1407 | \f | |
1408 | ;;; peephole optimizer | |
1409 | ||
1410 | (defconst byte-tagref-ops (cons 'TAG byte-goto-ops)) | |
1411 | ||
1412 | (defconst byte-conditional-ops | |
1413 | '(byte-goto-if-nil byte-goto-if-not-nil byte-goto-if-nil-else-pop | |
1414 | byte-goto-if-not-nil-else-pop)) | |
1415 | ||
1416 | (defconst byte-after-unbind-ops | |
1417 | '(byte-constant byte-dup | |
1418 | byte-symbolp byte-consp byte-stringp byte-listp byte-numberp byte-integerp | |
43fd1680 | 1419 | byte-eq byte-not |
1c393159 | 1420 | byte-cons byte-list1 byte-list2 ; byte-list3 byte-list4 |
cb88b56e RS |
1421 | byte-interactive-p) |
1422 | ;; How about other side-effect-free-ops? Is it safe to move an | |
1423 | ;; error invocation (such as from nth) out of an unwind-protect? | |
43fd1680 RS |
1424 | ;; No, it is not, because the unwind-protect forms can alter |
1425 | ;; the inside of the object to which nth would apply. | |
1426 | ;; For the same reason, byte-equal was deleted from this list. | |
cb88b56e | 1427 | "Byte-codes that can be moved past an unbind.") |
1c393159 JB |
1428 | |
1429 | (defconst byte-compile-side-effect-and-error-free-ops | |
1430 | '(byte-constant byte-dup byte-symbolp byte-consp byte-stringp byte-listp | |
1431 | byte-integerp byte-numberp byte-eq byte-equal byte-not byte-car-safe | |
1432 | byte-cdr-safe byte-cons byte-list1 byte-list2 byte-point byte-point-max | |
1433 | byte-point-min byte-following-char byte-preceding-char | |
1434 | byte-current-column byte-eolp byte-eobp byte-bolp byte-bobp | |
1435 | byte-current-buffer byte-interactive-p)) | |
1436 | ||
1437 | (defconst byte-compile-side-effect-free-ops | |
a1506d29 | 1438 | (nconc |
1c393159 JB |
1439 | '(byte-varref byte-nth byte-memq byte-car byte-cdr byte-length byte-aref |
1440 | byte-symbol-value byte-get byte-concat2 byte-concat3 byte-sub1 byte-add1 | |
1441 | byte-eqlsign byte-gtr byte-lss byte-leq byte-geq byte-diff byte-negate | |
1442 | byte-plus byte-max byte-min byte-mult byte-char-after byte-char-syntax | |
1443 | byte-buffer-substring byte-string= byte-string< byte-nthcdr byte-elt | |
1444 | byte-member byte-assq byte-quo byte-rem) | |
1445 | byte-compile-side-effect-and-error-free-ops)) | |
1446 | ||
e856a453 SM |
1447 | ;; This crock is because of the way DEFVAR_BOOL variables work. |
1448 | ;; Consider the code | |
1449 | ;; | |
1450 | ;; (defun foo (flag) | |
1451 | ;; (let ((old-pop-ups pop-up-windows) | |
1452 | ;; (pop-up-windows flag)) | |
1453 | ;; (cond ((not (eq pop-up-windows old-pop-ups)) | |
1454 | ;; (setq old-pop-ups pop-up-windows) | |
1455 | ;; ...)))) | |
1456 | ;; | |
1457 | ;; Uncompiled, old-pop-ups will always be set to nil or t, even if FLAG is | |
1458 | ;; something else. But if we optimize | |
1459 | ;; | |
1460 | ;; varref flag | |
1461 | ;; varbind pop-up-windows | |
1462 | ;; varref pop-up-windows | |
1463 | ;; not | |
1464 | ;; to | |
1465 | ;; varref flag | |
1466 | ;; dup | |
1467 | ;; varbind pop-up-windows | |
1468 | ;; not | |
1469 | ;; | |
1470 | ;; we break the program, because it will appear that pop-up-windows and | |
1471 | ;; old-pop-ups are not EQ when really they are. So we have to know what | |
1472 | ;; the BOOL variables are, and not perform this optimization on them. | |
1473 | ||
1474 | ;; The variable `byte-boolean-vars' is now primitive and updated | |
1475 | ;; automatically by DEFVAR_BOOL. | |
1c393159 JB |
1476 | |
1477 | (defun byte-optimize-lapcode (lap &optional for-effect) | |
e856a453 SM |
1478 | "Simple peephole optimizer. LAP is both modified and returned. |
1479 | If FOR-EFFECT is non-nil, the return value is assumed to be of no importance." | |
944425c0 DL |
1480 | (let (lap0 |
1481 | lap1 | |
1482 | lap2 | |
1c393159 JB |
1483 | (keep-going 'first-time) |
1484 | (add-depth 0) | |
1485 | rest tmp tmp2 tmp3 | |
1486 | (side-effect-free (if byte-compile-delete-errors | |
1487 | byte-compile-side-effect-free-ops | |
1488 | byte-compile-side-effect-and-error-free-ops))) | |
1489 | (while keep-going | |
1490 | (or (eq keep-going 'first-time) | |
1491 | (byte-compile-log-lap " ---- next pass")) | |
1492 | (setq rest lap | |
1493 | keep-going nil) | |
1494 | (while rest | |
1495 | (setq lap0 (car rest) | |
1496 | lap1 (nth 1 rest) | |
1497 | lap2 (nth 2 rest)) | |
1498 | ||
1499 | ;; You may notice that sequences like "dup varset discard" are | |
1500 | ;; optimized but sequences like "dup varset TAG1: discard" are not. | |
1501 | ;; You may be tempted to change this; resist that temptation. | |
1502 | (cond ;; | |
1503 | ;; <side-effect-free> pop --> <deleted> | |
1504 | ;; ...including: | |
1505 | ;; const-X pop --> <deleted> | |
1506 | ;; varref-X pop --> <deleted> | |
1507 | ;; dup pop --> <deleted> | |
1508 | ;; | |
1509 | ((and (eq 'byte-discard (car lap1)) | |
1510 | (memq (car lap0) side-effect-free)) | |
1511 | (setq keep-going t) | |
1512 | (setq tmp (aref byte-stack+-info (symbol-value (car lap0)))) | |
1513 | (setq rest (cdr rest)) | |
1514 | (cond ((= tmp 1) | |
1515 | (byte-compile-log-lap | |
1516 | " %s discard\t-->\t<deleted>" lap0) | |
1517 | (setq lap (delq lap0 (delq lap1 lap)))) | |
1518 | ((= tmp 0) | |
1519 | (byte-compile-log-lap | |
1520 | " %s discard\t-->\t<deleted> discard" lap0) | |
1521 | (setq lap (delq lap0 lap))) | |
1522 | ((= tmp -1) | |
1523 | (byte-compile-log-lap | |
1524 | " %s discard\t-->\tdiscard discard" lap0) | |
1525 | (setcar lap0 'byte-discard) | |
1526 | (setcdr lap0 0)) | |
1527 | ((error "Optimizer error: too much on the stack")))) | |
1528 | ;; | |
1529 | ;; goto*-X X: --> X: | |
1530 | ;; | |
1531 | ((and (memq (car lap0) byte-goto-ops) | |
1532 | (eq (cdr lap0) lap1)) | |
1533 | (cond ((eq (car lap0) 'byte-goto) | |
1534 | (setq lap (delq lap0 lap)) | |
1535 | (setq tmp "<deleted>")) | |
1536 | ((memq (car lap0) byte-goto-always-pop-ops) | |
1537 | (setcar lap0 (setq tmp 'byte-discard)) | |
1538 | (setcdr lap0 0)) | |
1539 | ((error "Depth conflict at tag %d" (nth 2 lap0)))) | |
1540 | (and (memq byte-optimize-log '(t byte)) | |
1541 | (byte-compile-log " (goto %s) %s:\t-->\t%s %s:" | |
1542 | (nth 1 lap1) (nth 1 lap1) | |
1543 | tmp (nth 1 lap1))) | |
1544 | (setq keep-going t)) | |
1545 | ;; | |
1546 | ;; varset-X varref-X --> dup varset-X | |
1547 | ;; varbind-X varref-X --> dup varbind-X | |
1548 | ;; const/dup varset-X varref-X --> const/dup varset-X const/dup | |
1549 | ;; const/dup varbind-X varref-X --> const/dup varbind-X const/dup | |
1550 | ;; The latter two can enable other optimizations. | |
1551 | ;; | |
1552 | ((and (eq 'byte-varref (car lap2)) | |
1553 | (eq (cdr lap1) (cdr lap2)) | |
1554 | (memq (car lap1) '(byte-varset byte-varbind))) | |
1555 | (if (and (setq tmp (memq (car (cdr lap2)) byte-boolean-vars)) | |
1556 | (not (eq (car lap0) 'byte-constant))) | |
1557 | nil | |
1558 | (setq keep-going t) | |
1559 | (if (memq (car lap0) '(byte-constant byte-dup)) | |
1560 | (progn | |
1561 | (setq tmp (if (or (not tmp) | |
e1f0df62 DL |
1562 | (byte-compile-const-symbol-p |
1563 | (car (cdr lap0)))) | |
1c393159 JB |
1564 | (cdr lap0) |
1565 | (byte-compile-get-constant t))) | |
1566 | (byte-compile-log-lap " %s %s %s\t-->\t%s %s %s" | |
1567 | lap0 lap1 lap2 lap0 lap1 | |
1568 | (cons (car lap0) tmp)) | |
1569 | (setcar lap2 (car lap0)) | |
1570 | (setcdr lap2 tmp)) | |
1571 | (byte-compile-log-lap " %s %s\t-->\tdup %s" lap1 lap2 lap1) | |
1572 | (setcar lap2 (car lap1)) | |
1573 | (setcar lap1 'byte-dup) | |
1574 | (setcdr lap1 0) | |
1575 | ;; The stack depth gets locally increased, so we will | |
1576 | ;; increase maxdepth in case depth = maxdepth here. | |
1577 | ;; This can cause the third argument to byte-code to | |
1578 | ;; be larger than necessary. | |
1579 | (setq add-depth 1)))) | |
1580 | ;; | |
1581 | ;; dup varset-X discard --> varset-X | |
1582 | ;; dup varbind-X discard --> varbind-X | |
1583 | ;; (the varbind variant can emerge from other optimizations) | |
1584 | ;; | |
1585 | ((and (eq 'byte-dup (car lap0)) | |
1586 | (eq 'byte-discard (car lap2)) | |
1587 | (memq (car lap1) '(byte-varset byte-varbind))) | |
1588 | (byte-compile-log-lap " dup %s discard\t-->\t%s" lap1 lap1) | |
1589 | (setq keep-going t | |
1590 | rest (cdr rest)) | |
1591 | (setq lap (delq lap0 (delq lap2 lap)))) | |
1592 | ;; | |
1593 | ;; not goto-X-if-nil --> goto-X-if-non-nil | |
1594 | ;; not goto-X-if-non-nil --> goto-X-if-nil | |
1595 | ;; | |
1596 | ;; it is wrong to do the same thing for the -else-pop variants. | |
1597 | ;; | |
1598 | ((and (eq 'byte-not (car lap0)) | |
1599 | (or (eq 'byte-goto-if-nil (car lap1)) | |
1600 | (eq 'byte-goto-if-not-nil (car lap1)))) | |
1601 | (byte-compile-log-lap " not %s\t-->\t%s" | |
1602 | lap1 | |
1603 | (cons | |
1604 | (if (eq (car lap1) 'byte-goto-if-nil) | |
1605 | 'byte-goto-if-not-nil | |
1606 | 'byte-goto-if-nil) | |
1607 | (cdr lap1))) | |
1608 | (setcar lap1 (if (eq (car lap1) 'byte-goto-if-nil) | |
1609 | 'byte-goto-if-not-nil | |
1610 | 'byte-goto-if-nil)) | |
1611 | (setq lap (delq lap0 lap)) | |
1612 | (setq keep-going t)) | |
1613 | ;; | |
1614 | ;; goto-X-if-nil goto-Y X: --> goto-Y-if-non-nil X: | |
1615 | ;; goto-X-if-non-nil goto-Y X: --> goto-Y-if-nil X: | |
1616 | ;; | |
1617 | ;; it is wrong to do the same thing for the -else-pop variants. | |
a1506d29 | 1618 | ;; |
1c393159 JB |
1619 | ((and (or (eq 'byte-goto-if-nil (car lap0)) |
1620 | (eq 'byte-goto-if-not-nil (car lap0))) ; gotoX | |
1621 | (eq 'byte-goto (car lap1)) ; gotoY | |
1622 | (eq (cdr lap0) lap2)) ; TAG X | |
1623 | (let ((inverse (if (eq 'byte-goto-if-nil (car lap0)) | |
1624 | 'byte-goto-if-not-nil 'byte-goto-if-nil))) | |
1625 | (byte-compile-log-lap " %s %s %s:\t-->\t%s %s:" | |
1626 | lap0 lap1 lap2 | |
1627 | (cons inverse (cdr lap1)) lap2) | |
1628 | (setq lap (delq lap0 lap)) | |
1629 | (setcar lap1 inverse) | |
1630 | (setq keep-going t))) | |
1631 | ;; | |
1632 | ;; const goto-if-* --> whatever | |
1633 | ;; | |
1634 | ((and (eq 'byte-constant (car lap0)) | |
1635 | (memq (car lap1) byte-conditional-ops)) | |
1636 | (cond ((if (or (eq (car lap1) 'byte-goto-if-nil) | |
1637 | (eq (car lap1) 'byte-goto-if-nil-else-pop)) | |
1638 | (car (cdr lap0)) | |
1639 | (not (car (cdr lap0)))) | |
1640 | (byte-compile-log-lap " %s %s\t-->\t<deleted>" | |
1641 | lap0 lap1) | |
1642 | (setq rest (cdr rest) | |
1643 | lap (delq lap0 (delq lap1 lap)))) | |
1644 | (t | |
1645 | (if (memq (car lap1) byte-goto-always-pop-ops) | |
1646 | (progn | |
1647 | (byte-compile-log-lap " %s %s\t-->\t%s" | |
1648 | lap0 lap1 (cons 'byte-goto (cdr lap1))) | |
1649 | (setq lap (delq lap0 lap))) | |
1650 | (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 | |
1651 | (cons 'byte-goto (cdr lap1)))) | |
1652 | (setcar lap1 'byte-goto))) | |
1653 | (setq keep-going t)) | |
1654 | ;; | |
1655 | ;; varref-X varref-X --> varref-X dup | |
1656 | ;; varref-X [dup ...] varref-X --> varref-X [dup ...] dup | |
1657 | ;; We don't optimize the const-X variations on this here, | |
1658 | ;; because that would inhibit some goto optimizations; we | |
1659 | ;; optimize the const-X case after all other optimizations. | |
1660 | ;; | |
1661 | ((and (eq 'byte-varref (car lap0)) | |
1662 | (progn | |
1663 | (setq tmp (cdr rest)) | |
1664 | (while (eq (car (car tmp)) 'byte-dup) | |
1665 | (setq tmp (cdr tmp))) | |
1666 | t) | |
1667 | (eq (cdr lap0) (cdr (car tmp))) | |
1668 | (eq 'byte-varref (car (car tmp)))) | |
1669 | (if (memq byte-optimize-log '(t byte)) | |
1670 | (let ((str "")) | |
1671 | (setq tmp2 (cdr rest)) | |
1672 | (while (not (eq tmp tmp2)) | |
1673 | (setq tmp2 (cdr tmp2) | |
1674 | str (concat str " dup"))) | |
1675 | (byte-compile-log-lap " %s%s %s\t-->\t%s%s dup" | |
1676 | lap0 str lap0 lap0 str))) | |
1677 | (setq keep-going t) | |
1678 | (setcar (car tmp) 'byte-dup) | |
1679 | (setcdr (car tmp) 0) | |
1680 | (setq rest tmp)) | |
1681 | ;; | |
1682 | ;; TAG1: TAG2: --> TAG1: <deleted> | |
1683 | ;; (and other references to TAG2 are replaced with TAG1) | |
1684 | ;; | |
1685 | ((and (eq (car lap0) 'TAG) | |
1686 | (eq (car lap1) 'TAG)) | |
1687 | (and (memq byte-optimize-log '(t byte)) | |
eb8c3be9 | 1688 | (byte-compile-log " adjacent tags %d and %d merged" |
1c393159 JB |
1689 | (nth 1 lap1) (nth 1 lap0))) |
1690 | (setq tmp3 lap) | |
1691 | (while (setq tmp2 (rassq lap0 tmp3)) | |
1692 | (setcdr tmp2 lap1) | |
1693 | (setq tmp3 (cdr (memq tmp2 tmp3)))) | |
1694 | (setq lap (delq lap0 lap) | |
1695 | keep-going t)) | |
1696 | ;; | |
1697 | ;; unused-TAG: --> <deleted> | |
1698 | ;; | |
1699 | ((and (eq 'TAG (car lap0)) | |
1700 | (not (rassq lap0 lap))) | |
1701 | (and (memq byte-optimize-log '(t byte)) | |
1702 | (byte-compile-log " unused tag %d removed" (nth 1 lap0))) | |
1703 | (setq lap (delq lap0 lap) | |
1704 | keep-going t)) | |
1705 | ;; | |
1706 | ;; goto ... --> goto <delete until TAG or end> | |
1707 | ;; return ... --> return <delete until TAG or end> | |
1708 | ;; | |
1709 | ((and (memq (car lap0) '(byte-goto byte-return)) | |
1710 | (not (memq (car lap1) '(TAG nil)))) | |
1711 | (setq tmp rest) | |
1712 | (let ((i 0) | |
1713 | (opt-p (memq byte-optimize-log '(t lap))) | |
1714 | str deleted) | |
1715 | (while (and (setq tmp (cdr tmp)) | |
1716 | (not (eq 'TAG (car (car tmp))))) | |
1717 | (if opt-p (setq deleted (cons (car tmp) deleted) | |
1718 | str (concat str " %s") | |
1719 | i (1+ i)))) | |
1720 | (if opt-p | |
a1506d29 | 1721 | (let ((tagstr |
1c393159 | 1722 | (if (eq 'TAG (car (car tmp))) |
dec4e22e | 1723 | (format "%d:" (car (cdr (car tmp)))) |
1c393159 JB |
1724 | (or (car tmp) "")))) |
1725 | (if (< i 6) | |
1726 | (apply 'byte-compile-log-lap-1 | |
1727 | (concat " %s" str | |
1728 | " %s\t-->\t%s <deleted> %s") | |
1729 | lap0 | |
1730 | (nconc (nreverse deleted) | |
1731 | (list tagstr lap0 tagstr))) | |
1732 | (byte-compile-log-lap | |
1733 | " %s <%d unreachable op%s> %s\t-->\t%s <deleted> %s" | |
1734 | lap0 i (if (= i 1) "" "s") | |
1735 | tagstr lap0 tagstr)))) | |
1736 | (rplacd rest tmp)) | |
1737 | (setq keep-going t)) | |
1738 | ;; | |
1739 | ;; <safe-op> unbind --> unbind <safe-op> | |
1740 | ;; (this may enable other optimizations.) | |
1741 | ;; | |
1742 | ((and (eq 'byte-unbind (car lap1)) | |
1743 | (memq (car lap0) byte-after-unbind-ops)) | |
1744 | (byte-compile-log-lap " %s %s\t-->\t%s %s" lap0 lap1 lap1 lap0) | |
1745 | (setcar rest lap1) | |
1746 | (setcar (cdr rest) lap0) | |
1747 | (setq keep-going t)) | |
1748 | ;; | |
1749 | ;; varbind-X unbind-N --> discard unbind-(N-1) | |
1750 | ;; save-excursion unbind-N --> unbind-(N-1) | |
1751 | ;; save-restriction unbind-N --> unbind-(N-1) | |
1752 | ;; | |
1753 | ((and (eq 'byte-unbind (car lap1)) | |
1754 | (memq (car lap0) '(byte-varbind byte-save-excursion | |
1755 | byte-save-restriction)) | |
1756 | (< 0 (cdr lap1))) | |
1757 | (if (zerop (setcdr lap1 (1- (cdr lap1)))) | |
1758 | (delq lap1 rest)) | |
1759 | (if (eq (car lap0) 'byte-varbind) | |
1760 | (setcar rest (cons 'byte-discard 0)) | |
1761 | (setq lap (delq lap0 lap))) | |
1762 | (byte-compile-log-lap " %s %s\t-->\t%s %s" | |
1763 | lap0 (cons (car lap1) (1+ (cdr lap1))) | |
1764 | (if (eq (car lap0) 'byte-varbind) | |
1765 | (car rest) | |
1766 | (car (cdr rest))) | |
1767 | (if (and (/= 0 (cdr lap1)) | |
1768 | (eq (car lap0) 'byte-varbind)) | |
1769 | (car (cdr rest)) | |
1770 | "")) | |
1771 | (setq keep-going t)) | |
1772 | ;; | |
1773 | ;; goto*-X ... X: goto-Y --> goto*-Y | |
1774 | ;; goto-X ... X: return --> return | |
1775 | ;; | |
1776 | ((and (memq (car lap0) byte-goto-ops) | |
1777 | (memq (car (setq tmp (nth 1 (memq (cdr lap0) lap)))) | |
1778 | '(byte-goto byte-return))) | |
1779 | (cond ((and (not (eq tmp lap0)) | |
1780 | (or (eq (car lap0) 'byte-goto) | |
1781 | (eq (car tmp) 'byte-goto))) | |
1782 | (byte-compile-log-lap " %s [%s]\t-->\t%s" | |
1783 | (car lap0) tmp tmp) | |
1784 | (if (eq (car tmp) 'byte-return) | |
1785 | (setcar lap0 'byte-return)) | |
1786 | (setcdr lap0 (cdr tmp)) | |
1787 | (setq keep-going t)))) | |
1788 | ;; | |
1789 | ;; goto-*-else-pop X ... X: goto-if-* --> whatever | |
1790 | ;; goto-*-else-pop X ... X: discard --> whatever | |
1791 | ;; | |
1792 | ((and (memq (car lap0) '(byte-goto-if-nil-else-pop | |
1793 | byte-goto-if-not-nil-else-pop)) | |
1794 | (memq (car (car (setq tmp (cdr (memq (cdr lap0) lap))))) | |
1795 | (eval-when-compile | |
1796 | (cons 'byte-discard byte-conditional-ops))) | |
1797 | (not (eq lap0 (car tmp)))) | |
1798 | (setq tmp2 (car tmp)) | |
1799 | (setq tmp3 (assq (car lap0) '((byte-goto-if-nil-else-pop | |
1800 | byte-goto-if-nil) | |
1801 | (byte-goto-if-not-nil-else-pop | |
1802 | byte-goto-if-not-nil)))) | |
1803 | (if (memq (car tmp2) tmp3) | |
1804 | (progn (setcar lap0 (car tmp2)) | |
1805 | (setcdr lap0 (cdr tmp2)) | |
1806 | (byte-compile-log-lap " %s-else-pop [%s]\t-->\t%s" | |
1807 | (car lap0) tmp2 lap0)) | |
1808 | ;; Get rid of the -else-pop's and jump one step further. | |
1809 | (or (eq 'TAG (car (nth 1 tmp))) | |
1810 | (setcdr tmp (cons (byte-compile-make-tag) | |
1811 | (cdr tmp)))) | |
1812 | (byte-compile-log-lap " %s [%s]\t-->\t%s <skip>" | |
1813 | (car lap0) tmp2 (nth 1 tmp3)) | |
1814 | (setcar lap0 (nth 1 tmp3)) | |
1815 | (setcdr lap0 (nth 1 tmp))) | |
1816 | (setq keep-going t)) | |
1817 | ;; | |
1818 | ;; const goto-X ... X: goto-if-* --> whatever | |
1819 | ;; const goto-X ... X: discard --> whatever | |
1820 | ;; | |
1821 | ((and (eq (car lap0) 'byte-constant) | |
1822 | (eq (car lap1) 'byte-goto) | |
1823 | (memq (car (car (setq tmp (cdr (memq (cdr lap1) lap))))) | |
1824 | (eval-when-compile | |
1825 | (cons 'byte-discard byte-conditional-ops))) | |
1826 | (not (eq lap1 (car tmp)))) | |
1827 | (setq tmp2 (car tmp)) | |
1828 | (cond ((memq (car tmp2) | |
1829 | (if (null (car (cdr lap0))) | |
1830 | '(byte-goto-if-nil byte-goto-if-nil-else-pop) | |
1831 | '(byte-goto-if-not-nil | |
1832 | byte-goto-if-not-nil-else-pop))) | |
1833 | (byte-compile-log-lap " %s goto [%s]\t-->\t%s %s" | |
1834 | lap0 tmp2 lap0 tmp2) | |
1835 | (setcar lap1 (car tmp2)) | |
1836 | (setcdr lap1 (cdr tmp2)) | |
1837 | ;; Let next step fix the (const,goto-if*) sequence. | |
1838 | (setq rest (cons nil rest))) | |
1839 | (t | |
1840 | ;; Jump one step further | |
1841 | (byte-compile-log-lap | |
1842 | " %s goto [%s]\t-->\t<deleted> goto <skip>" | |
1843 | lap0 tmp2) | |
1844 | (or (eq 'TAG (car (nth 1 tmp))) | |
1845 | (setcdr tmp (cons (byte-compile-make-tag) | |
1846 | (cdr tmp)))) | |
1847 | (setcdr lap1 (car (cdr tmp))) | |
1848 | (setq lap (delq lap0 lap)))) | |
1849 | (setq keep-going t)) | |
1850 | ;; | |
1851 | ;; X: varref-Y ... varset-Y goto-X --> | |
1852 | ;; X: varref-Y Z: ... dup varset-Y goto-Z | |
1853 | ;; (varset-X goto-BACK, BACK: varref-X --> copy the varref down.) | |
1854 | ;; (This is so usual for while loops that it is worth handling). | |
1855 | ;; | |
1856 | ((and (eq (car lap1) 'byte-varset) | |
1857 | (eq (car lap2) 'byte-goto) | |
1858 | (not (memq (cdr lap2) rest)) ;Backwards jump | |
1859 | (eq (car (car (setq tmp (cdr (memq (cdr lap2) lap))))) | |
1860 | 'byte-varref) | |
1861 | (eq (cdr (car tmp)) (cdr lap1)) | |
1862 | (not (memq (car (cdr lap1)) byte-boolean-vars))) | |
1863 | ;;(byte-compile-log-lap " Pulled %s to end of loop" (car tmp)) | |
1864 | (let ((newtag (byte-compile-make-tag))) | |
1865 | (byte-compile-log-lap | |
1866 | " %s: %s ... %s %s\t-->\t%s: %s %s: ... %s %s %s" | |
1867 | (nth 1 (cdr lap2)) (car tmp) | |
1868 | lap1 lap2 | |
1869 | (nth 1 (cdr lap2)) (car tmp) | |
1870 | (nth 1 newtag) 'byte-dup lap1 | |
1871 | (cons 'byte-goto newtag) | |
1872 | ) | |
1873 | (setcdr rest (cons (cons 'byte-dup 0) (cdr rest))) | |
1874 | (setcdr tmp (cons (setcdr lap2 newtag) (cdr tmp)))) | |
1875 | (setq add-depth 1) | |
1876 | (setq keep-going t)) | |
1877 | ;; | |
1878 | ;; goto-X Y: ... X: goto-if*-Y --> goto-if-not-*-X+1 Y: | |
1879 | ;; (This can pull the loop test to the end of the loop) | |
1880 | ;; | |
1881 | ((and (eq (car lap0) 'byte-goto) | |
1882 | (eq (car lap1) 'TAG) | |
1883 | (eq lap1 | |
1884 | (cdr (car (setq tmp (cdr (memq (cdr lap0) lap)))))) | |
1885 | (memq (car (car tmp)) | |
1886 | '(byte-goto byte-goto-if-nil byte-goto-if-not-nil | |
1887 | byte-goto-if-nil-else-pop))) | |
1888 | ;; (byte-compile-log-lap " %s %s, %s %s --> moved conditional" | |
1889 | ;; lap0 lap1 (cdr lap0) (car tmp)) | |
1890 | (let ((newtag (byte-compile-make-tag))) | |
1891 | (byte-compile-log-lap | |
1892 | "%s %s: ... %s: %s\t-->\t%s ... %s:" | |
1893 | lap0 (nth 1 lap1) (nth 1 (cdr lap0)) (car tmp) | |
1894 | (cons (cdr (assq (car (car tmp)) | |
1895 | '((byte-goto-if-nil . byte-goto-if-not-nil) | |
1896 | (byte-goto-if-not-nil . byte-goto-if-nil) | |
1897 | (byte-goto-if-nil-else-pop . | |
1898 | byte-goto-if-not-nil-else-pop) | |
1899 | (byte-goto-if-not-nil-else-pop . | |
1900 | byte-goto-if-nil-else-pop)))) | |
1901 | newtag) | |
a1506d29 | 1902 | |
1c393159 JB |
1903 | (nth 1 newtag) |
1904 | ) | |
1905 | (setcdr tmp (cons (setcdr lap0 newtag) (cdr tmp))) | |
1906 | (if (eq (car (car tmp)) 'byte-goto-if-nil-else-pop) | |
1907 | ;; We can handle this case but not the -if-not-nil case, | |
1908 | ;; because we won't know which non-nil constant to push. | |
1909 | (setcdr rest (cons (cons 'byte-constant | |
1910 | (byte-compile-get-constant nil)) | |
1911 | (cdr rest)))) | |
1912 | (setcar lap0 (nth 1 (memq (car (car tmp)) | |
1913 | '(byte-goto-if-nil-else-pop | |
1914 | byte-goto-if-not-nil | |
1915 | byte-goto-if-nil | |
1916 | byte-goto-if-not-nil | |
1917 | byte-goto byte-goto)))) | |
1918 | ) | |
1919 | (setq keep-going t)) | |
1920 | ) | |
1921 | (setq rest (cdr rest))) | |
1922 | ) | |
1923 | ;; Cleanup stage: | |
1924 | ;; Rebuild byte-compile-constants / byte-compile-variables. | |
1925 | ;; Simple optimizations that would inhibit other optimizations if they | |
1926 | ;; were done in the optimizing loop, and optimizations which there is no | |
1927 | ;; need to do more than once. | |
1928 | (setq byte-compile-constants nil | |
1929 | byte-compile-variables nil) | |
1930 | (setq rest lap) | |
1931 | (while rest | |
1932 | (setq lap0 (car rest) | |
1933 | lap1 (nth 1 rest)) | |
1934 | (if (memq (car lap0) byte-constref-ops) | |
3ecf67a1 GM |
1935 | (if (or (eq (car lap0) 'byte-constant) |
1936 | (eq (car lap0) 'byte-constant2)) | |
1937 | (unless (memq (cdr lap0) byte-compile-constants) | |
1c393159 | 1938 | (setq byte-compile-constants (cons (cdr lap0) |
3ecf67a1 GM |
1939 | byte-compile-constants))) |
1940 | (unless (memq (cdr lap0) byte-compile-variables) | |
1941 | (setq byte-compile-variables (cons (cdr lap0) | |
1942 | byte-compile-variables))))) | |
1c393159 JB |
1943 | (cond (;; |
1944 | ;; const-C varset-X const-C --> const-C dup varset-X | |
1945 | ;; const-C varbind-X const-C --> const-C dup varbind-X | |
1946 | ;; | |
1947 | (and (eq (car lap0) 'byte-constant) | |
1948 | (eq (car (nth 2 rest)) 'byte-constant) | |
3ecf67a1 | 1949 | (eq (cdr lap0) (cdr (nth 2 rest))) |
1c393159 JB |
1950 | (memq (car lap1) '(byte-varbind byte-varset))) |
1951 | (byte-compile-log-lap " %s %s %s\t-->\t%s dup %s" | |
1952 | lap0 lap1 lap0 lap0 lap1) | |
1953 | (setcar (cdr (cdr rest)) (cons (car lap1) (cdr lap1))) | |
1954 | (setcar (cdr rest) (cons 'byte-dup 0)) | |
1955 | (setq add-depth 1)) | |
1956 | ;; | |
1957 | ;; const-X [dup/const-X ...] --> const-X [dup ...] dup | |
1958 | ;; varref-X [dup/varref-X ...] --> varref-X [dup ...] dup | |
1959 | ;; | |
1960 | ((memq (car lap0) '(byte-constant byte-varref)) | |
1961 | (setq tmp rest | |
1962 | tmp2 nil) | |
1963 | (while (progn | |
1964 | (while (eq 'byte-dup (car (car (setq tmp (cdr tmp)))))) | |
1965 | (and (eq (cdr lap0) (cdr (car tmp))) | |
1966 | (eq (car lap0) (car (car tmp))))) | |
1967 | (setcar tmp (cons 'byte-dup 0)) | |
1968 | (setq tmp2 t)) | |
1969 | (if tmp2 | |
1970 | (byte-compile-log-lap | |
dec4e22e | 1971 | " %s [dup/%s]...\t-->\t%s dup..." lap0 lap0 lap0))) |
1c393159 JB |
1972 | ;; |
1973 | ;; unbind-N unbind-M --> unbind-(N+M) | |
1974 | ;; | |
1975 | ((and (eq 'byte-unbind (car lap0)) | |
1976 | (eq 'byte-unbind (car lap1))) | |
1977 | (byte-compile-log-lap " %s %s\t-->\t%s" lap0 lap1 | |
1978 | (cons 'byte-unbind | |
1979 | (+ (cdr lap0) (cdr lap1)))) | |
1980 | (setq keep-going t) | |
1981 | (setq lap (delq lap0 lap)) | |
1982 | (setcdr lap1 (+ (cdr lap1) (cdr lap0)))) | |
1983 | ) | |
1984 | (setq rest (cdr rest))) | |
1985 | (setq byte-compile-maxdepth (+ byte-compile-maxdepth add-depth))) | |
1986 | lap) | |
1987 | ||
1ffa4286 | 1988 | (provide 'byte-opt) |
1c393159 JB |
1989 | |
1990 | \f | |
1991 | ;; To avoid "lisp nesting exceeds max-lisp-eval-depth" when this file compiles | |
1992 | ;; itself, compile some of its most used recursive functions (at load time). | |
1993 | ;; | |
1994 | (eval-when-compile | |
96d699f3 | 1995 | (or (byte-code-function-p (symbol-function 'byte-optimize-form)) |
1c393159 JB |
1996 | (assq 'byte-code (symbol-function 'byte-optimize-form)) |
1997 | (let ((byte-optimize nil) | |
1998 | (byte-compile-warnings nil)) | |
72d8b544 SM |
1999 | (mapcar (lambda (x) |
2000 | (or noninteractive (message "compiling %s..." x)) | |
2001 | (byte-compile x) | |
2002 | (or noninteractive (message "compiling %s...done" x))) | |
1c393159 JB |
2003 | '(byte-optimize-form |
2004 | byte-optimize-body | |
2005 | byte-optimize-predicate | |
2006 | byte-optimize-binary-predicate | |
2007 | ;; Inserted some more than necessary, to speed it up. | |
2008 | byte-optimize-form-code-walker | |
2009 | byte-optimize-lapcode)))) | |
2010 | nil) | |
3eac9910 | 2011 | |
f61b7b7f | 2012 | ;; arch-tag: 0f14076b-737e-4bef-aae6-908826ec1ff1 |
3eac9910 | 2013 | ;;; byte-opt.el ends here |