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4fefc3a8 AW |
1 | ;;; Continuation-passing style (CPS) intermediate language (IL) |
2 | ||
3 | ;; Copyright (C) 2013 Free Software Foundation, Inc. | |
4 | ||
5 | ;;;; This library is free software; you can redistribute it and/or | |
6 | ;;;; modify it under the terms of the GNU Lesser General Public | |
7 | ;;;; License as published by the Free Software Foundation; either | |
8 | ;;;; version 3 of the License, or (at your option) any later version. | |
9 | ;;;; | |
10 | ;;;; This library is distributed in the hope that it will be useful, | |
11 | ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | ;;;; Lesser General Public License for more details. | |
14 | ;;;; | |
15 | ;;;; You should have received a copy of the GNU Lesser General Public | |
16 | ;;;; License along with this library; if not, write to the Free Software | |
17 | ;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
18 | ||
19 | ;;; Commentary: | |
20 | ;;; | |
21 | ;;; This pass converts Tree-IL to the continuation-passing style (CPS) | |
22 | ;;; language. | |
23 | ;;; | |
24 | ;;; CPS is a lower-level representation than Tree-IL. Converting to | |
25 | ;;; CPS, beyond adding names for all control points and all values, | |
26 | ;;; simplifies expressions in the following ways, among others: | |
27 | ;;; | |
28 | ;;; * Fixing the order of evaluation. | |
29 | ;;; | |
30 | ;;; * Converting assigned variables to boxed variables. | |
31 | ;;; | |
32 | ;;; * Requiring that Scheme's <letrec> has already been lowered to | |
33 | ;;; <fix>. | |
34 | ;;; | |
35 | ;;; * Inlining default-value initializers into lambda-case | |
36 | ;;; expressions. | |
37 | ;;; | |
38 | ;;; * Inlining prompt bodies. | |
39 | ;;; | |
40 | ;;; * Turning toplevel and module references into primcalls. This | |
41 | ;;; involves explicitly modelling the "scope" of toplevel lookups | |
42 | ;;; (indicating the module with respect to which toplevel bindings | |
43 | ;;; are resolved). | |
44 | ;;; | |
45 | ;;; The utility of CPS is that it gives a name to everything: every | |
46 | ;;; intermediate value, and every control point (continuation). As such | |
47 | ;;; it is more verbose than Tree-IL, but at the same time more simple as | |
48 | ;;; the number of concepts is reduced. | |
49 | ;;; | |
50 | ;;; Code: | |
51 | ||
52 | (define-module (language tree-il compile-cps) | |
53 | #:use-module (ice-9 match) | |
54 | #:use-module ((srfi srfi-1) #:select (fold fold-right filter-map)) | |
55 | #:use-module (srfi srfi-26) | |
56 | #:use-module ((system foreign) #:select (make-pointer pointer->scm)) | |
57 | #:use-module (language cps) | |
58 | #:use-module (language cps primitives) | |
59 | #:use-module (language tree-il analyze) | |
60 | #:use-module (language tree-il optimize) | |
b7f10def | 61 | #:use-module ((language tree-il) #:hide (let-gensyms)) |
4fefc3a8 AW |
62 | #:export (compile-cps)) |
63 | ||
64 | ;;; Guile's semantics are that a toplevel lambda captures a reference on | |
65 | ;;; the current module, and that all contained lambdas use that module | |
66 | ;;; to resolve toplevel variables. This parameter tracks whether or not | |
67 | ;;; we are in a toplevel lambda. If we are in a lambda, the parameter | |
68 | ;;; is bound to a fresh name identifying the module that was current | |
69 | ;;; when the toplevel lambda is defined. | |
70 | ;;; | |
71 | ;;; This is more complicated than it need be. Ideally we should resolve | |
72 | ;;; all toplevel bindings to bindings from specific modules, unless the | |
73 | ;;; binding is unbound. This is always valid if the compilation unit | |
74 | ;;; sets the module explicitly, as when compiling a module, but it | |
75 | ;;; doesn't work for files auto-compiled for use with `load'. | |
76 | ;;; | |
77 | (define current-topbox-scope (make-parameter #f)) | |
78 | ||
79 | (define (toplevel-box src name bound? val-proc) | |
80 | (let-gensyms (name-sym bound?-sym kbox box) | |
81 | (build-cps-term | |
82 | ($letconst (('name name-sym name) | |
83 | ('bound? bound?-sym bound?)) | |
84 | ($letk ((kbox src ($kargs ('box) (box) ,(val-proc box)))) | |
85 | ,(match (current-topbox-scope) | |
86 | (#f | |
87 | (build-cps-term | |
88 | ($continue kbox | |
89 | ($primcall 'resolve | |
90 | (name-sym bound?-sym))))) | |
91 | (scope | |
92 | (let-gensyms (scope-sym) | |
93 | (build-cps-term | |
94 | ($letconst (('scope scope-sym scope)) | |
95 | ($continue kbox | |
96 | ($primcall 'cached-toplevel-box | |
97 | (scope-sym name-sym bound?-sym))))))))))))) | |
98 | ||
99 | (define (module-box src module name public? bound? val-proc) | |
100 | (let-gensyms (module-sym name-sym public?-sym bound?-sym kbox box) | |
101 | (build-cps-term | |
102 | ($letconst (('module module-sym module) | |
103 | ('name name-sym name) | |
104 | ('public? public?-sym public?) | |
105 | ('bound? bound?-sym bound?)) | |
106 | ($letk ((kbox src ($kargs ('box) (box) ,(val-proc box)))) | |
107 | ($continue kbox | |
108 | ($primcall 'cached-module-box | |
109 | (module-sym name-sym public?-sym bound?-sym)))))))) | |
110 | ||
111 | (define (capture-toplevel-scope src scope k) | |
112 | (let-gensyms (module scope-sym kmodule) | |
113 | (build-cps-term | |
114 | ($letconst (('scope scope-sym scope)) | |
115 | ($letk ((kmodule src ($kargs ('module) (module) | |
116 | ($continue k | |
117 | ($primcall 'cache-current-module! | |
118 | (module scope-sym)))))) | |
119 | ($continue kmodule | |
120 | ($primcall 'current-module ()))))))) | |
121 | ||
122 | (define (fold-formals proc seed arity gensyms inits) | |
123 | (match arity | |
124 | (($ $arity req opt rest kw allow-other-keys?) | |
125 | (let () | |
126 | (define (fold-req names gensyms seed) | |
127 | (match names | |
128 | (() (fold-opt opt gensyms inits seed)) | |
129 | ((name . names) | |
130 | (proc name (car gensyms) #f | |
131 | (fold-req names (cdr gensyms) seed))))) | |
132 | (define (fold-opt names gensyms inits seed) | |
133 | (match names | |
134 | (() (fold-rest rest gensyms inits seed)) | |
135 | ((name . names) | |
136 | (proc name (car gensyms) (car inits) | |
137 | (fold-opt names (cdr gensyms) (cdr inits) seed))))) | |
138 | (define (fold-rest rest gensyms inits seed) | |
139 | (match rest | |
140 | (#f (fold-kw kw gensyms inits seed)) | |
141 | (name (proc name (car gensyms) #f | |
142 | (fold-kw kw (cdr gensyms) inits seed))))) | |
143 | (define (fold-kw kw gensyms inits seed) | |
144 | (match kw | |
145 | (() | |
146 | (unless (null? gensyms) | |
147 | (error "too many gensyms")) | |
148 | (unless (null? inits) | |
149 | (error "too many inits")) | |
150 | seed) | |
151 | (((key name var) . kw) | |
152 | (unless (eq? var (car gensyms)) | |
153 | (error "unexpected keyword arg order")) | |
154 | (proc name var (car inits) | |
155 | (fold-kw kw (cdr gensyms) (cdr inits) seed))))) | |
156 | (fold-req req gensyms seed))))) | |
157 | ||
158 | (define (unbound? src sym kt kf) | |
159 | (define tc8-iflag 4) | |
160 | (define unbound-val 9) | |
161 | (define unbound-bits (logior (ash unbound-val 8) tc8-iflag)) | |
162 | (let-gensyms (unbound ktest) | |
163 | (build-cps-term | |
164 | ($letconst (('unbound unbound (pointer->scm (make-pointer unbound-bits)))) | |
165 | ($letk ((ktest src ($kif kt kf))) | |
166 | ($continue ktest | |
167 | ($primcall 'eq? (sym unbound)))))))) | |
168 | ||
169 | (define (init-default-value name sym subst init body) | |
170 | (match (assq-ref subst sym) | |
171 | ((subst-sym box?) | |
172 | (let ((src (tree-il-src init))) | |
173 | (define (maybe-box k make-body) | |
174 | (if box? | |
175 | (let-gensyms (kbox phi) | |
176 | (build-cps-term | |
177 | ($letk ((kbox src ($kargs (name) (phi) | |
178 | ($continue k ($primcall 'box (phi)))))) | |
179 | ,(make-body kbox)))) | |
180 | (make-body k))) | |
181 | (let-gensyms (knext kbound kunbound) | |
182 | (build-cps-term | |
183 | ($letk ((knext src ($kargs (name) (subst-sym) ,body))) | |
184 | ,(maybe-box | |
185 | knext | |
186 | (lambda (k) | |
187 | (build-cps-term | |
188 | ($letk ((kbound src ($kargs () () ($continue k ($var sym)))) | |
189 | (kunbound src ($kargs () () ,(convert init k subst)))) | |
190 | ,(unbound? src sym kunbound kbound)))))))))))) | |
191 | ||
192 | ;; exp k-name alist -> term | |
193 | (define (convert exp k subst) | |
194 | ;; exp (v-name -> term) -> term | |
195 | (define (convert-arg exp k) | |
196 | (match exp | |
197 | (($ <lexical-ref> src name sym) | |
198 | (match (assq-ref subst sym) | |
199 | ((box #t) | |
200 | (let-gensyms (kunboxed unboxed) | |
201 | (build-cps-term | |
202 | ($letk ((kunboxed src ($kargs ('unboxed) (unboxed) ,(k unboxed)))) | |
203 | ($continue kunboxed ($primcall 'box-ref (box))))))) | |
204 | ((subst #f) (k subst)) | |
205 | (#f (k sym)))) | |
206 | (else | |
207 | (let ((src (tree-il-src exp))) | |
208 | (let-gensyms (karg arg) | |
209 | (build-cps-term | |
210 | ($letk ((karg src ($kargs ('arg) (arg) ,(k arg)))) | |
211 | ,(convert exp karg subst)))))))) | |
212 | ;; (exp ...) ((v-name ...) -> term) -> term | |
213 | (define (convert-args exps k) | |
214 | (match exps | |
215 | (() (k '())) | |
216 | ((exp . exps) | |
217 | (convert-arg exp | |
218 | (lambda (name) | |
219 | (convert-args exps | |
220 | (lambda (names) | |
221 | (k (cons name names))))))))) | |
222 | (define (box-bound-var name sym body) | |
223 | (match (assq-ref subst sym) | |
224 | ((box #t) | |
225 | (let-gensyms (k) | |
226 | (build-cps-term | |
227 | ($letk ((k #f ($kargs (name) (box) ,body))) | |
228 | ($continue k ($primcall 'box (sym))))))) | |
229 | (else body))) | |
230 | ||
231 | (match exp | |
232 | (($ <lexical-ref> src name sym) | |
233 | (match (assq-ref subst sym) | |
234 | ((box #t) (build-cps-term ($continue k ($primcall 'box-ref (box))))) | |
235 | ((subst #f) (build-cps-term ($continue k ($var subst)))) | |
236 | (#f (build-cps-term ($continue k ($var sym)))))) | |
237 | ||
238 | (($ <void> src) | |
239 | (build-cps-term ($continue k ($void)))) | |
240 | ||
241 | (($ <const> src exp) | |
242 | (build-cps-term ($continue k ($const exp)))) | |
243 | ||
244 | (($ <primitive-ref> src name) | |
245 | (build-cps-term ($continue k ($prim name)))) | |
246 | ||
247 | (($ <lambda> fun-src meta body) | |
248 | (let () | |
249 | (define (convert-clauses body ktail) | |
250 | (match body | |
251 | (#f '()) | |
252 | (($ <lambda-case> src req opt rest kw inits gensyms body alternate) | |
253 | (let* ((arity (make-$arity req (or opt '()) rest | |
254 | (if kw (cdr kw) '()) (and kw (car kw)))) | |
255 | (names (fold-formals (lambda (name sym init names) | |
256 | (cons name names)) | |
257 | '() | |
258 | arity gensyms inits))) | |
259 | (cons | |
260 | (let-gensyms (kclause kargs) | |
261 | (build-cps-cont | |
262 | (kclause | |
263 | src | |
264 | ($kclause ,arity | |
265 | (kargs | |
266 | src | |
267 | ($kargs names gensyms | |
268 | ,(fold-formals | |
269 | (lambda (name sym init body) | |
270 | (if init | |
271 | (init-default-value name sym subst init body) | |
272 | (box-bound-var name sym body))) | |
273 | (convert body ktail subst) | |
274 | arity gensyms inits))))))) | |
275 | (convert-clauses alternate ktail)))))) | |
276 | (if (current-topbox-scope) | |
277 | (let-gensyms (kentry self ktail) | |
278 | (build-cps-term | |
279 | ($continue k | |
280 | ($fun meta '() | |
281 | (kentry fun-src | |
282 | ($kentry self (ktail #f ($ktail)) | |
283 | ,(convert-clauses body ktail))))))) | |
284 | (let-gensyms (scope kscope) | |
285 | (build-cps-term | |
286 | ($letk ((kscope fun-src | |
287 | ($kargs () () | |
288 | ,(parameterize ((current-topbox-scope scope)) | |
289 | (convert exp k subst))))) | |
290 | ,(capture-toplevel-scope fun-src scope kscope))))))) | |
291 | ||
292 | (($ <module-ref> src mod name public?) | |
293 | (module-box | |
294 | src mod name public? #t | |
295 | (lambda (box) | |
296 | (build-cps-term ($continue k ($primcall 'box-ref (box))))))) | |
297 | ||
298 | (($ <module-set> src mod name public? exp) | |
299 | (convert-arg exp | |
300 | (lambda (val) | |
301 | (module-box | |
302 | src mod name public? #f | |
303 | (lambda (box) | |
304 | (build-cps-term ($continue k ($primcall 'box-set! (box val))))))))) | |
305 | ||
306 | (($ <toplevel-ref> src name) | |
307 | (toplevel-box | |
308 | src name #t | |
309 | (lambda (box) | |
310 | (build-cps-term ($continue k ($primcall 'box-ref (box))))))) | |
311 | ||
312 | (($ <toplevel-set> src name exp) | |
313 | (convert-arg exp | |
314 | (lambda (val) | |
315 | (toplevel-box | |
316 | src name #f | |
317 | (lambda (box) | |
318 | (build-cps-term ($continue k ($primcall 'box-set! (box val))))))))) | |
319 | ||
320 | (($ <toplevel-define> src name exp) | |
321 | (convert-arg exp | |
322 | (lambda (val) | |
323 | (let-gensyms (kname name-sym) | |
324 | (build-cps-term | |
325 | ($letconst (('name name-sym name)) | |
326 | ($continue k ($primcall 'define! (name-sym val))))))))) | |
327 | ||
328 | (($ <call> src proc args) | |
329 | (convert-args (cons proc args) | |
330 | (match-lambda | |
331 | ((proc . args) | |
332 | (build-cps-term ($continue k ($call proc args))))))) | |
333 | ||
334 | (($ <primcall> src name args) | |
58dee5b9 AW |
335 | (cond |
336 | ((branching-primitive? name) | |
337 | (convert (make-conditional src exp (make-const #f #t) | |
338 | (make-const #f #f)) | |
339 | k subst)) | |
92afe25d AW |
340 | ((and (eq? name 'vector) |
341 | (and-map (match-lambda | |
342 | ((or ($ <const>) | |
343 | ($ <void>) | |
344 | ($ <lambda>) | |
345 | ($ <lexical-ref>)) #t) | |
346 | (_ #f)) | |
347 | args)) | |
58dee5b9 AW |
348 | ;; Some macros generate calls to "vector" with like 300 |
349 | ;; arguments. Since we eventually compile to make-vector and | |
350 | ;; vector-set!, it reduces live variable pressure to allocate the | |
92afe25d AW |
351 | ;; vector first, then set values as they are produced, if we can |
352 | ;; prove that no value can capture the continuation. (More on | |
353 | ;; that caveat here: | |
354 | ;; http://wingolog.org/archives/2013/11/02/scheme-quiz-time). | |
355 | ;; | |
356 | ;; Normally we would do this transformation in the compiler, but | |
357 | ;; it's quite tricky there and quite easy here, so hold your nose | |
58dee5b9 AW |
358 | ;; while we drop some smelly code. |
359 | (convert (let ((len (length args))) | |
360 | (let-gensyms (v) | |
361 | (make-let src | |
362 | (list 'v) | |
363 | (list v) | |
364 | (list (make-primcall src 'make-vector | |
365 | (list (make-const #f len) | |
366 | (make-const #f #f)))) | |
367 | (fold (lambda (arg n tail) | |
368 | (make-seq | |
369 | src | |
370 | (make-primcall | |
371 | src 'vector-set! | |
372 | (list (make-lexical-ref src 'v v) | |
373 | (make-const #f n) | |
374 | arg)) | |
375 | tail)) | |
376 | (make-lexical-ref src 'v v) | |
377 | (reverse args) (reverse (iota len)))))) | |
378 | k subst)) | |
379 | (else | |
380 | (convert-args args | |
381 | (lambda (args) | |
382 | (build-cps-term ($continue k ($primcall name args)))))))) | |
4fefc3a8 AW |
383 | |
384 | ;; Prompts with inline handlers. | |
385 | (($ <prompt> src escape-only? tag body | |
386 | ($ <lambda> hsrc hmeta | |
387 | ($ <lambda-case> _ hreq #f hrest #f () hsyms hbody #f))) | |
388 | ;; Handler: | |
389 | ;; khargs: check args returned to handler, -> khbody | |
390 | ;; khbody: the handler, -> k | |
391 | ;; | |
392 | ;; Post-body: | |
393 | ;; krest: collect return vals from body to list, -> kpop | |
394 | ;; kpop: pop the prompt, -> kprim | |
395 | ;; kprim: load the values primitive, -> kret | |
396 | ;; kret: (apply values rvals), -> k | |
397 | ;; | |
398 | ;; Escape prompts evaluate the body with the continuation of krest. | |
399 | ;; Otherwise we do a no-inline call to body, continuing to krest. | |
400 | (convert-arg tag | |
401 | (lambda (tag) | |
402 | (let ((hnames (append hreq (if hrest (list hrest) '())))) | |
403 | (let-gensyms (khargs khbody kret kprim prim kpop krest vals kbody) | |
404 | (build-cps-term | |
405 | ($letk* ((khbody hsrc ($kargs hnames hsyms | |
406 | ,(fold box-bound-var | |
407 | (convert hbody k subst) | |
408 | hnames hsyms))) | |
409 | (khargs hsrc ($ktrunc hreq hrest khbody)) | |
410 | (kpop src | |
411 | ($kargs ('rest) (vals) | |
412 | ($letk ((kret | |
413 | src | |
414 | ($kargs () () | |
415 | ($letk ((kprim | |
416 | src | |
417 | ($kargs ('prim) (prim) | |
418 | ($continue k | |
419 | ($primcall 'apply | |
420 | (prim vals)))))) | |
421 | ($continue kprim | |
422 | ($prim 'values)))))) | |
423 | ($continue kret | |
8d59d55e | 424 | ($primcall 'unwind ()))))) |
4fefc3a8 AW |
425 | (krest src ($ktrunc '() 'rest kpop))) |
426 | ,(if escape-only? | |
427 | (build-cps-term | |
428 | ($letk ((kbody (tree-il-src body) | |
429 | ($kargs () () | |
430 | ,(convert body krest subst)))) | |
96af4a18 | 431 | ($continue kbody ($prompt #t tag khargs kpop)))) |
4fefc3a8 AW |
432 | (convert-arg body |
433 | (lambda (thunk) | |
434 | (build-cps-term | |
435 | ($letk ((kbody (tree-il-src body) | |
436 | ($kargs () () | |
437 | ($continue krest | |
438 | ($primcall 'call-thunk/no-inline | |
439 | (thunk)))))) | |
440 | ($continue kbody | |
96af4a18 | 441 | ($prompt #f tag khargs kpop)))))))))))))) |
4fefc3a8 AW |
442 | |
443 | ;; Eta-convert prompts without inline handlers. | |
444 | (($ <prompt> src escape-only? tag body handler) | |
b7f10def AW |
445 | (let-gensyms (h args) |
446 | (convert | |
447 | (make-let | |
448 | src (list 'h) (list h) (list handler) | |
449 | (make-seq | |
450 | src | |
451 | (make-conditional | |
452 | src | |
453 | (make-primcall src 'procedure? (list (make-lexical-ref #f 'h h))) | |
454 | (make-void src) | |
455 | (make-primcall | |
456 | src 'scm-error | |
457 | (list | |
458 | (make-const #f 'wrong-type-arg) | |
459 | (make-const #f "call-with-prompt") | |
460 | (make-const #f "Wrong type (expecting procedure): ~S") | |
461 | (make-primcall #f 'list (list (make-lexical-ref #f 'h h))) | |
462 | (make-primcall #f 'list (list (make-lexical-ref #f 'h h)))))) | |
463 | (make-prompt | |
464 | src escape-only? tag body | |
465 | (make-lambda | |
466 | src '() | |
467 | (make-lambda-case | |
468 | src '() #f 'args #f '() (list args) | |
469 | (make-primcall | |
470 | src 'apply | |
471 | (list (make-lexical-ref #f 'h h) | |
472 | (make-lexical-ref #f 'args args))) | |
473 | #f))))) | |
474 | k | |
475 | subst))) | |
4fefc3a8 | 476 | |
486013d6 AW |
477 | (($ <abort> src tag args ($ <const> _ ())) |
478 | (convert-args (cons tag args) | |
479 | (lambda (args*) | |
480 | (build-cps-term | |
481 | ($continue k ($primcall 'abort-to-prompt args*)))))) | |
482 | ||
4fefc3a8 | 483 | (($ <abort> src tag args tail) |
486013d6 AW |
484 | (convert-args (append (list (make-primitive-ref #f 'abort-to-prompt) |
485 | tag) | |
486 | args | |
487 | (list tail)) | |
4fefc3a8 | 488 | (lambda (args*) |
486013d6 AW |
489 | (build-cps-term |
490 | ($continue k ($primcall 'apply args*)))))) | |
4fefc3a8 AW |
491 | |
492 | (($ <conditional> src test consequent alternate) | |
493 | (let-gensyms (kif kt kf) | |
494 | (build-cps-term | |
495 | ($letk* ((kt (tree-il-src consequent) ($kargs () () | |
496 | ,(convert consequent k subst))) | |
497 | (kf (tree-il-src alternate) ($kargs () () | |
498 | ,(convert alternate k subst))) | |
499 | (kif src ($kif kt kf))) | |
500 | ,(match test | |
501 | (($ <primcall> src (? branching-primitive? name) args) | |
502 | (convert-args args | |
503 | (lambda (args) | |
504 | (build-cps-term ($continue kif ($primcall name args)))))) | |
505 | (_ (convert-arg test | |
506 | (lambda (test) | |
507 | (build-cps-term ($continue kif ($var test))))))))))) | |
508 | ||
509 | (($ <lexical-set> src name gensym exp) | |
510 | (convert-arg exp | |
511 | (lambda (exp) | |
512 | (match (assq-ref subst gensym) | |
513 | ((box #t) | |
514 | (build-cps-term | |
515 | ($continue k ($primcall 'box-set! (box exp))))))))) | |
516 | ||
517 | (($ <seq> src head tail) | |
518 | (let-gensyms (ktrunc kseq) | |
519 | (build-cps-term | |
520 | ($letk* ((kseq (tree-il-src tail) ($kargs () () | |
521 | ,(convert tail k subst))) | |
522 | (ktrunc src ($ktrunc '() #f kseq))) | |
523 | ,(convert head ktrunc subst))))) | |
524 | ||
525 | (($ <let> src names syms vals body) | |
526 | (let lp ((names names) (syms syms) (vals vals)) | |
527 | (match (list names syms vals) | |
528 | ((() () ()) (convert body k subst)) | |
529 | (((name . names) (sym . syms) (val . vals)) | |
530 | (let-gensyms (klet) | |
531 | (build-cps-term | |
532 | ($letk ((klet src ($kargs (name) (sym) | |
533 | ,(box-bound-var name sym | |
534 | (lp names syms vals))))) | |
535 | ,(convert val klet subst)))))))) | |
536 | ||
537 | (($ <fix> src names gensyms funs body) | |
538 | ;; Some letrecs can be contified; that happens later. | |
539 | (if (current-topbox-scope) | |
540 | (let-gensyms (self) | |
541 | (build-cps-term | |
542 | ($letrec names | |
543 | gensyms | |
544 | (map (lambda (fun) | |
545 | (match (convert fun k subst) | |
546 | (($ $continue _ (and fun ($ $fun))) | |
547 | fun))) | |
548 | funs) | |
549 | ,(convert body k subst)))) | |
550 | (let-gensyms (scope kscope) | |
551 | (build-cps-term | |
552 | ($letk ((kscope src ($kargs () () | |
553 | ,(parameterize ((current-topbox-scope scope)) | |
554 | (convert exp k subst))))) | |
555 | ,(capture-toplevel-scope src scope kscope)))))) | |
556 | ||
557 | (($ <let-values> src exp | |
558 | ($ <lambda-case> lsrc req #f rest #f () syms body #f)) | |
559 | (let ((names (append req (if rest (list rest) '())))) | |
560 | (let-gensyms (ktrunc kargs) | |
561 | (build-cps-term | |
562 | ($letk* ((kargs src ($kargs names syms | |
563 | ,(fold box-bound-var | |
564 | (convert body k subst) | |
565 | names syms))) | |
566 | (ktrunc src ($ktrunc req rest kargs))) | |
567 | ,(convert exp ktrunc subst)))))))) | |
568 | ||
569 | (define (build-subst exp) | |
570 | "Compute a mapping from lexical gensyms to substituted gensyms. The | |
571 | usual reason to replace one variable by another is assignment | |
572 | conversion. Default argument values is the other reason. | |
573 | ||
574 | Returns a list of (ORIG-SYM SUBST-SYM BOXED?). A true value for BOXED? | |
575 | indicates that the replacement variable is in a box." | |
576 | (define (box-set-vars exp subst) | |
577 | (match exp | |
578 | (($ <lexical-set> src name sym exp) | |
579 | (if (assq sym subst) | |
580 | subst | |
581 | (cons (list sym (gensym "b") #t) subst))) | |
582 | (_ subst))) | |
583 | (define (default-args exp subst) | |
584 | (match exp | |
585 | (($ <lambda-case> src req opt rest kw inits gensyms body alternate) | |
586 | (fold-formals (lambda (name sym init subst) | |
587 | (if init | |
588 | (let ((box? (match (assq-ref subst sym) | |
589 | ((box #t) #t) | |
590 | (#f #f))) | |
591 | (subst-sym (gensym (symbol->string name)))) | |
592 | (cons (list sym subst-sym box?) subst)) | |
593 | subst)) | |
594 | subst | |
595 | (make-$arity req (or opt '()) rest | |
596 | (if kw (cdr kw) '()) (and kw (car kw))) | |
597 | gensyms | |
598 | inits)) | |
599 | (_ subst))) | |
600 | (tree-il-fold box-set-vars default-args '() exp)) | |
601 | ||
602 | (define (cps-convert/thunk exp) | |
603 | (let ((src (tree-il-src exp))) | |
604 | (let-gensyms (kinit init ktail kclause kbody) | |
605 | (build-cps-exp | |
606 | ($fun '() '() | |
607 | (kinit src | |
608 | ($kentry init | |
609 | (ktail #f ($ktail)) | |
610 | ((kclause src | |
611 | ($kclause ('() '() #f '() #f) | |
612 | (kbody src | |
613 | ($kargs () () | |
614 | ,(convert exp ktail | |
615 | (build-subst exp)))))))))))))) | |
616 | ||
617 | (define *comp-module* (make-fluid)) | |
618 | ||
619 | (define %warning-passes | |
620 | `((unused-variable . ,unused-variable-analysis) | |
621 | (unused-toplevel . ,unused-toplevel-analysis) | |
622 | (unbound-variable . ,unbound-variable-analysis) | |
623 | (arity-mismatch . ,arity-analysis) | |
624 | (format . ,format-analysis))) | |
625 | ||
626 | (define (optimize-tree-il x e opts) | |
627 | (define warnings | |
628 | (or (and=> (memq #:warnings opts) cadr) | |
629 | '())) | |
630 | ||
631 | ;; Go through the warning passes. | |
632 | (let ((analyses (filter-map (lambda (kind) | |
633 | (assoc-ref %warning-passes kind)) | |
634 | warnings))) | |
635 | (analyze-tree analyses x e)) | |
636 | ||
637 | (optimize x e opts)) | |
638 | ||
639 | (define (compile-cps exp env opts) | |
640 | (values (cps-convert/thunk (optimize-tree-il exp env opts)) | |
641 | env | |
642 | env)) | |
643 | ||
644 | ;;; Local Variables: | |
645 | ;;; eval: (put 'convert-arg 'scheme-indent-function 1) | |
646 | ;;; eval: (put 'convert-args 'scheme-indent-function 1) | |
647 | ;;; End: |