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4fefc3a8 AW |
1 | ;;; Continuation-passing style (CPS) intermediate language (IL) |
2 | ||
7ab76a83 | 3 | ;; Copyright (C) 2013, 2014 Free Software Foundation, Inc. |
4fefc3a8 AW |
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) | |
828ed944 | 61 | #:use-module (language tree-il) |
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)) | |
48e65b44 AW |
78 | (define scope-counter (make-parameter #f)) |
79 | ||
80 | (define (fresh-scope-id) | |
81 | (let ((scope-id (scope-counter))) | |
82 | (scope-counter (1+ scope-id)) | |
83 | scope-id)) | |
4fefc3a8 AW |
84 | |
85 | (define (toplevel-box src name bound? val-proc) | |
9a1dfb7d | 86 | (let-fresh (kbox) (name-sym bound?-sym box) |
4fefc3a8 AW |
87 | (build-cps-term |
88 | ($letconst (('name name-sym name) | |
89 | ('bound? bound?-sym bound?)) | |
6e422a35 | 90 | ($letk ((kbox ($kargs ('box) (box) ,(val-proc box)))) |
4fefc3a8 AW |
91 | ,(match (current-topbox-scope) |
92 | (#f | |
93 | (build-cps-term | |
6e422a35 | 94 | ($continue kbox src |
4fefc3a8 AW |
95 | ($primcall 'resolve |
96 | (name-sym bound?-sym))))) | |
48e65b44 | 97 | (scope-id |
9a1dfb7d | 98 | (let-fresh () (scope-sym) |
4fefc3a8 | 99 | (build-cps-term |
48e65b44 | 100 | ($letconst (('scope scope-sym scope-id)) |
6e422a35 | 101 | ($continue kbox src |
4fefc3a8 AW |
102 | ($primcall 'cached-toplevel-box |
103 | (scope-sym name-sym bound?-sym))))))))))))) | |
104 | ||
105 | (define (module-box src module name public? bound? val-proc) | |
9a1dfb7d | 106 | (let-fresh (kbox) (module-sym name-sym public?-sym bound?-sym box) |
4fefc3a8 AW |
107 | (build-cps-term |
108 | ($letconst (('module module-sym module) | |
109 | ('name name-sym name) | |
110 | ('public? public?-sym public?) | |
111 | ('bound? bound?-sym bound?)) | |
6e422a35 AW |
112 | ($letk ((kbox ($kargs ('box) (box) ,(val-proc box)))) |
113 | ($continue kbox src | |
4fefc3a8 AW |
114 | ($primcall 'cached-module-box |
115 | (module-sym name-sym public?-sym bound?-sym)))))))) | |
116 | ||
48e65b44 | 117 | (define (capture-toplevel-scope src scope-id k) |
9a1dfb7d | 118 | (let-fresh (kmodule) (module scope-sym) |
4fefc3a8 | 119 | (build-cps-term |
48e65b44 | 120 | ($letconst (('scope scope-sym scope-id)) |
6e422a35 AW |
121 | ($letk ((kmodule ($kargs ('module) (module) |
122 | ($continue k src | |
123 | ($primcall 'cache-current-module! | |
124 | (module scope-sym)))))) | |
125 | ($continue kmodule src | |
4fefc3a8 AW |
126 | ($primcall 'current-module ()))))))) |
127 | ||
128 | (define (fold-formals proc seed arity gensyms inits) | |
129 | (match arity | |
130 | (($ $arity req opt rest kw allow-other-keys?) | |
131 | (let () | |
132 | (define (fold-req names gensyms seed) | |
133 | (match names | |
134 | (() (fold-opt opt gensyms inits seed)) | |
135 | ((name . names) | |
136 | (proc name (car gensyms) #f | |
137 | (fold-req names (cdr gensyms) seed))))) | |
138 | (define (fold-opt names gensyms inits seed) | |
139 | (match names | |
140 | (() (fold-rest rest gensyms inits seed)) | |
141 | ((name . names) | |
142 | (proc name (car gensyms) (car inits) | |
143 | (fold-opt names (cdr gensyms) (cdr inits) seed))))) | |
144 | (define (fold-rest rest gensyms inits seed) | |
145 | (match rest | |
146 | (#f (fold-kw kw gensyms inits seed)) | |
147 | (name (proc name (car gensyms) #f | |
148 | (fold-kw kw (cdr gensyms) inits seed))))) | |
149 | (define (fold-kw kw gensyms inits seed) | |
150 | (match kw | |
151 | (() | |
152 | (unless (null? gensyms) | |
153 | (error "too many gensyms")) | |
154 | (unless (null? inits) | |
155 | (error "too many inits")) | |
156 | seed) | |
157 | (((key name var) . kw) | |
e6cf744a AW |
158 | ;; Could be that var is not a gensym any more. |
159 | (when (symbol? var) | |
160 | (unless (eq? var (car gensyms)) | |
161 | (error "unexpected keyword arg order"))) | |
162 | (proc name (car gensyms) (car inits) | |
4fefc3a8 AW |
163 | (fold-kw kw (cdr gensyms) (cdr inits) seed))))) |
164 | (fold-req req gensyms seed))))) | |
165 | ||
e6cf744a | 166 | (define (unbound? src var kt kf) |
4fefc3a8 AW |
167 | (define tc8-iflag 4) |
168 | (define unbound-val 9) | |
169 | (define unbound-bits (logior (ash unbound-val 8) tc8-iflag)) | |
9a1dfb7d | 170 | (let-fresh (ktest) (unbound) |
4fefc3a8 | 171 | (build-cps-term |
9a1dfb7d AW |
172 | ($letconst (('unbound unbound |
173 | (pointer->scm (make-pointer unbound-bits)))) | |
6e422a35 AW |
174 | ($letk ((ktest ($kif kt kf))) |
175 | ($continue ktest src | |
e6cf744a | 176 | ($primcall 'eq? (var unbound)))))))) |
4fefc3a8 AW |
177 | |
178 | (define (init-default-value name sym subst init body) | |
e6cf744a AW |
179 | (match (hashq-ref subst sym) |
180 | ((orig-var subst-var box?) | |
4fefc3a8 AW |
181 | (let ((src (tree-il-src init))) |
182 | (define (maybe-box k make-body) | |
183 | (if box? | |
9a1dfb7d | 184 | (let-fresh (kbox) (phi) |
4fefc3a8 | 185 | (build-cps-term |
6e422a35 AW |
186 | ($letk ((kbox ($kargs (name) (phi) |
187 | ($continue k src ($primcall 'box (phi)))))) | |
4fefc3a8 AW |
188 | ,(make-body kbox)))) |
189 | (make-body k))) | |
9a1dfb7d | 190 | (let-fresh (knext kbound kunbound kreceive krest) (val rest) |
4fefc3a8 | 191 | (build-cps-term |
e6cf744a | 192 | ($letk ((knext ($kargs (name) (subst-var) ,body))) |
4fefc3a8 AW |
193 | ,(maybe-box |
194 | knext | |
195 | (lambda (k) | |
196 | (build-cps-term | |
13085a82 | 197 | ($letk ((kbound ($kargs () () ($continue k src |
e6cf744a | 198 | ($values (orig-var))))) |
31086641 AW |
199 | (krest ($kargs (name 'rest) (val rest) |
200 | ($continue k src ($values (val))))) | |
36527695 | 201 | (kreceive ($kreceive (list name) 'rest krest)) |
31086641 | 202 | (kunbound ($kargs () () |
36527695 | 203 | ,(convert init kreceive subst)))) |
e6cf744a | 204 | ,(unbound? src orig-var kunbound kbound)))))))))))) |
4fefc3a8 AW |
205 | |
206 | ;; exp k-name alist -> term | |
207 | (define (convert exp k subst) | |
208 | ;; exp (v-name -> term) -> term | |
209 | (define (convert-arg exp k) | |
210 | (match exp | |
211 | (($ <lexical-ref> src name sym) | |
e6cf744a AW |
212 | (match (hashq-ref subst sym) |
213 | ((orig-var box #t) | |
9a1dfb7d | 214 | (let-fresh (kunboxed) (unboxed) |
4fefc3a8 | 215 | (build-cps-term |
6e422a35 AW |
216 | ($letk ((kunboxed ($kargs ('unboxed) (unboxed) ,(k unboxed)))) |
217 | ($continue kunboxed src ($primcall 'box-ref (box))))))) | |
e6cf744a AW |
218 | ((orig-var subst-var #f) (k subst-var)) |
219 | (var (k var)))) | |
4fefc3a8 | 220 | (else |
9a1dfb7d | 221 | (let-fresh (kreceive karg) (arg rest) |
6e422a35 | 222 | (build-cps-term |
31086641 | 223 | ($letk ((karg ($kargs ('arg 'rest) (arg rest) ,(k arg))) |
36527695 AW |
224 | (kreceive ($kreceive '(arg) 'rest karg))) |
225 | ,(convert exp kreceive subst))))))) | |
4fefc3a8 AW |
226 | ;; (exp ...) ((v-name ...) -> term) -> term |
227 | (define (convert-args exps k) | |
228 | (match exps | |
229 | (() (k '())) | |
230 | ((exp . exps) | |
231 | (convert-arg exp | |
232 | (lambda (name) | |
233 | (convert-args exps | |
234 | (lambda (names) | |
235 | (k (cons name names))))))))) | |
236 | (define (box-bound-var name sym body) | |
e6cf744a AW |
237 | (match (hashq-ref subst sym) |
238 | ((orig-var subst-var #t) | |
9a1dfb7d | 239 | (let-fresh (k) () |
4fefc3a8 | 240 | (build-cps-term |
e6cf744a AW |
241 | ($letk ((k ($kargs (name) (subst-var) ,body))) |
242 | ($continue k #f ($primcall 'box (orig-var))))))) | |
4fefc3a8 | 243 | (else body))) |
e6cf744a AW |
244 | (define (bound-var sym) |
245 | (match (hashq-ref subst sym) | |
246 | ((var . _) var) | |
247 | ((? exact-integer? var) var))) | |
4fefc3a8 AW |
248 | |
249 | (match exp | |
250 | (($ <lexical-ref> src name sym) | |
e6cf744a AW |
251 | (rewrite-cps-term (hashq-ref subst sym) |
252 | ((orig-var box #t) ($continue k src ($primcall 'box-ref (box)))) | |
253 | ((orig-var subst-var #f) ($continue k src ($values (subst-var)))) | |
254 | (var ($continue k src ($values (var)))))) | |
4fefc3a8 AW |
255 | |
256 | (($ <void> src) | |
6e422a35 | 257 | (build-cps-term ($continue k src ($void)))) |
4fefc3a8 AW |
258 | |
259 | (($ <const> src exp) | |
6e422a35 | 260 | (build-cps-term ($continue k src ($const exp)))) |
4fefc3a8 AW |
261 | |
262 | (($ <primitive-ref> src name) | |
6e422a35 | 263 | (build-cps-term ($continue k src ($prim name)))) |
4fefc3a8 AW |
264 | |
265 | (($ <lambda> fun-src meta body) | |
266 | (let () | |
267 | (define (convert-clauses body ktail) | |
268 | (match body | |
90dce16d | 269 | (#f #f) |
4fefc3a8 AW |
270 | (($ <lambda-case> src req opt rest kw inits gensyms body alternate) |
271 | (let* ((arity (make-$arity req (or opt '()) rest | |
e6cf744a AW |
272 | (map (match-lambda |
273 | ((kw name sym) | |
274 | (list kw name (bound-var sym)))) | |
275 | (if kw (cdr kw) '())) | |
276 | (and kw (car kw)))) | |
4fefc3a8 AW |
277 | (names (fold-formals (lambda (name sym init names) |
278 | (cons name names)) | |
279 | '() | |
280 | arity gensyms inits))) | |
90dce16d AW |
281 | (let ((bound-vars (map bound-var gensyms))) |
282 | (let-fresh (kclause kargs) () | |
283 | (build-cps-cont | |
284 | (kclause | |
285 | ($kclause ,arity | |
286 | (kargs | |
287 | ($kargs names bound-vars | |
288 | ,(fold-formals | |
289 | (lambda (name sym init body) | |
290 | (if init | |
291 | (init-default-value name sym subst init body) | |
292 | (box-bound-var name sym body))) | |
293 | (convert body ktail subst) | |
294 | arity gensyms inits))) | |
295 | ,(convert-clauses alternate ktail)))))))))) | |
4fefc3a8 | 296 | (if (current-topbox-scope) |
8320f504 | 297 | (let-fresh (kfun ktail) (self) |
4fefc3a8 | 298 | (build-cps-term |
6e422a35 | 299 | ($continue k fun-src |
24b611e8 | 300 | ($fun '() |
8320f504 | 301 | (kfun ($kfun fun-src meta self (ktail ($ktail)) |
24b611e8 | 302 | ,(convert-clauses body ktail))))))) |
48e65b44 AW |
303 | (let ((scope-id (fresh-scope-id))) |
304 | (let-fresh (kscope) () | |
305 | (build-cps-term | |
306 | ($letk ((kscope | |
307 | ($kargs () () | |
308 | ,(parameterize ((current-topbox-scope scope-id)) | |
309 | (convert exp k subst))))) | |
310 | ,(capture-toplevel-scope fun-src scope-id kscope)))))))) | |
4fefc3a8 AW |
311 | |
312 | (($ <module-ref> src mod name public?) | |
313 | (module-box | |
314 | src mod name public? #t | |
315 | (lambda (box) | |
6e422a35 | 316 | (build-cps-term ($continue k src ($primcall 'box-ref (box))))))) |
4fefc3a8 AW |
317 | |
318 | (($ <module-set> src mod name public? exp) | |
319 | (convert-arg exp | |
320 | (lambda (val) | |
321 | (module-box | |
322 | src mod name public? #f | |
323 | (lambda (box) | |
6e422a35 AW |
324 | (build-cps-term |
325 | ($continue k src ($primcall 'box-set! (box val))))))))) | |
4fefc3a8 AW |
326 | |
327 | (($ <toplevel-ref> src name) | |
328 | (toplevel-box | |
329 | src name #t | |
330 | (lambda (box) | |
6e422a35 | 331 | (build-cps-term ($continue k src ($primcall 'box-ref (box))))))) |
4fefc3a8 AW |
332 | |
333 | (($ <toplevel-set> src name exp) | |
334 | (convert-arg exp | |
335 | (lambda (val) | |
336 | (toplevel-box | |
337 | src name #f | |
338 | (lambda (box) | |
6e422a35 AW |
339 | (build-cps-term |
340 | ($continue k src ($primcall 'box-set! (box val))))))))) | |
4fefc3a8 AW |
341 | |
342 | (($ <toplevel-define> src name exp) | |
343 | (convert-arg exp | |
344 | (lambda (val) | |
9a1dfb7d | 345 | (let-fresh (kname) (name-sym) |
4fefc3a8 AW |
346 | (build-cps-term |
347 | ($letconst (('name name-sym name)) | |
6e422a35 | 348 | ($continue k src ($primcall 'define! (name-sym val))))))))) |
4fefc3a8 AW |
349 | |
350 | (($ <call> src proc args) | |
351 | (convert-args (cons proc args) | |
352 | (match-lambda | |
353 | ((proc . args) | |
6e422a35 | 354 | (build-cps-term ($continue k src ($call proc args))))))) |
4fefc3a8 AW |
355 | |
356 | (($ <primcall> src name args) | |
58dee5b9 AW |
357 | (cond |
358 | ((branching-primitive? name) | |
e6cf744a AW |
359 | (convert-args args |
360 | (lambda (args) | |
361 | (let-fresh (kt kf kif) () | |
362 | (build-cps-term | |
363 | ($letk ((kt ($kargs () () ($continue k src ($const #t)))) | |
364 | (kf ($kargs () () ($continue k src ($const #f)))) | |
365 | (kif ($kif kt kf))) | |
366 | ($continue kif src ($primcall name args)))))))) | |
0d046513 AW |
367 | ((and (eq? name 'list) |
368 | (and-map (match-lambda | |
369 | ((or ($ <const>) | |
370 | ($ <void>) | |
371 | ($ <lambda>) | |
372 | ($ <lexical-ref>)) #t) | |
373 | (_ #f)) | |
374 | args)) | |
e6cf744a AW |
375 | ;; See note below in `canonicalize' about `vector'. The same |
376 | ;; thing applies to `list'. | |
0d046513 AW |
377 | (let lp ((args args) (k k)) |
378 | (match args | |
379 | (() | |
380 | (build-cps-term | |
6e422a35 | 381 | ($continue k src ($const '())))) |
0d046513 | 382 | ((arg . args) |
9a1dfb7d | 383 | (let-fresh (ktail) (tail) |
0d046513 | 384 | (build-cps-term |
6e422a35 | 385 | ($letk ((ktail ($kargs ('tail) (tail) |
0d046513 AW |
386 | ,(convert-arg arg |
387 | (lambda (head) | |
388 | (build-cps-term | |
6e422a35 | 389 | ($continue k src |
0d046513 AW |
390 | ($primcall 'cons (head tail))))))))) |
391 | ,(lp args ktail)))))))) | |
58dee5b9 AW |
392 | (else |
393 | (convert-args args | |
394 | (lambda (args) | |
6e422a35 | 395 | (build-cps-term ($continue k src ($primcall name args)))))))) |
4fefc3a8 AW |
396 | |
397 | ;; Prompts with inline handlers. | |
398 | (($ <prompt> src escape-only? tag body | |
399 | ($ <lambda> hsrc hmeta | |
400 | ($ <lambda-case> _ hreq #f hrest #f () hsyms hbody #f))) | |
401 | ;; Handler: | |
402 | ;; khargs: check args returned to handler, -> khbody | |
403 | ;; khbody: the handler, -> k | |
404 | ;; | |
405 | ;; Post-body: | |
406 | ;; krest: collect return vals from body to list, -> kpop | |
407 | ;; kpop: pop the prompt, -> kprim | |
408 | ;; kprim: load the values primitive, -> kret | |
409 | ;; kret: (apply values rvals), -> k | |
410 | ;; | |
411 | ;; Escape prompts evaluate the body with the continuation of krest. | |
412 | ;; Otherwise we do a no-inline call to body, continuing to krest. | |
413 | (convert-arg tag | |
414 | (lambda (tag) | |
e6cf744a AW |
415 | (let ((hnames (append hreq (if hrest (list hrest) '()))) |
416 | (bound-vars (map bound-var hsyms))) | |
9a1dfb7d | 417 | (let-fresh (khargs khbody kret kprim kpop krest kbody) (prim vals) |
4fefc3a8 | 418 | (build-cps-term |
36527695 | 419 | ;; FIXME: Attach hsrc to $kreceive. |
e6cf744a | 420 | ($letk* ((khbody ($kargs hnames bound-vars |
6e422a35 AW |
421 | ,(fold box-bound-var |
422 | (convert hbody k subst) | |
423 | hnames hsyms))) | |
36527695 | 424 | (khargs ($kreceive hreq hrest khbody)) |
6e422a35 | 425 | (kpop ($kargs ('rest) (vals) |
4fefc3a8 | 426 | ($letk ((kret |
4fefc3a8 AW |
427 | ($kargs () () |
428 | ($letk ((kprim | |
4fefc3a8 | 429 | ($kargs ('prim) (prim) |
6e422a35 | 430 | ($continue k src |
4fefc3a8 AW |
431 | ($primcall 'apply |
432 | (prim vals)))))) | |
6e422a35 | 433 | ($continue kprim src |
4fefc3a8 | 434 | ($prim 'values)))))) |
6e422a35 | 435 | ($continue kret src |
8d59d55e | 436 | ($primcall 'unwind ()))))) |
36527695 | 437 | (krest ($kreceive '() 'rest kpop))) |
4fefc3a8 AW |
438 | ,(if escape-only? |
439 | (build-cps-term | |
6e422a35 | 440 | ($letk ((kbody ($kargs () () |
4fefc3a8 | 441 | ,(convert body krest subst)))) |
7ab76a83 | 442 | ($continue kbody src ($prompt #t tag khargs)))) |
4fefc3a8 AW |
443 | (convert-arg body |
444 | (lambda (thunk) | |
445 | (build-cps-term | |
6e422a35 AW |
446 | ($letk ((kbody ($kargs () () |
447 | ($continue krest (tree-il-src body) | |
4fefc3a8 AW |
448 | ($primcall 'call-thunk/no-inline |
449 | (thunk)))))) | |
6e422a35 | 450 | ($continue kbody (tree-il-src body) |
7ab76a83 | 451 | ($prompt #f tag khargs)))))))))))))) |
4fefc3a8 | 452 | |
486013d6 AW |
453 | (($ <abort> src tag args ($ <const> _ ())) |
454 | (convert-args (cons tag args) | |
455 | (lambda (args*) | |
456 | (build-cps-term | |
6e422a35 AW |
457 | ($continue k src |
458 | ($primcall 'abort-to-prompt args*)))))) | |
486013d6 | 459 | |
4fefc3a8 | 460 | (($ <abort> src tag args tail) |
486013d6 AW |
461 | (convert-args (append (list (make-primitive-ref #f 'abort-to-prompt) |
462 | tag) | |
463 | args | |
464 | (list tail)) | |
4fefc3a8 | 465 | (lambda (args*) |
486013d6 | 466 | (build-cps-term |
6e422a35 | 467 | ($continue k src ($primcall 'apply args*)))))) |
4fefc3a8 AW |
468 | |
469 | (($ <conditional> src test consequent alternate) | |
9a1dfb7d | 470 | (let-fresh (kif kt kf) () |
4fefc3a8 | 471 | (build-cps-term |
6e422a35 AW |
472 | ($letk* ((kt ($kargs () () ,(convert consequent k subst))) |
473 | (kf ($kargs () () ,(convert alternate k subst))) | |
474 | (kif ($kif kt kf))) | |
4fefc3a8 AW |
475 | ,(match test |
476 | (($ <primcall> src (? branching-primitive? name) args) | |
477 | (convert-args args | |
478 | (lambda (args) | |
6e422a35 AW |
479 | (build-cps-term |
480 | ($continue kif src ($primcall name args)))))) | |
4fefc3a8 AW |
481 | (_ (convert-arg test |
482 | (lambda (test) | |
6e422a35 | 483 | (build-cps-term |
13085a82 | 484 | ($continue kif src ($values (test)))))))))))) |
4fefc3a8 AW |
485 | |
486 | (($ <lexical-set> src name gensym exp) | |
487 | (convert-arg exp | |
488 | (lambda (exp) | |
e6cf744a AW |
489 | (match (hashq-ref subst gensym) |
490 | ((orig-var box #t) | |
4fefc3a8 | 491 | (build-cps-term |
6e422a35 | 492 | ($continue k src ($primcall 'box-set! (box exp))))))))) |
4fefc3a8 AW |
493 | |
494 | (($ <seq> src head tail) | |
9a1dfb7d | 495 | (let-fresh (kreceive kseq) (vals) |
4fefc3a8 | 496 | (build-cps-term |
31086641 | 497 | ($letk* ((kseq ($kargs ('vals) (vals) |
6e422a35 | 498 | ,(convert tail k subst))) |
36527695 AW |
499 | (kreceive ($kreceive '() 'vals kseq))) |
500 | ,(convert head kreceive subst))))) | |
4fefc3a8 AW |
501 | |
502 | (($ <let> src names syms vals body) | |
503 | (let lp ((names names) (syms syms) (vals vals)) | |
504 | (match (list names syms vals) | |
505 | ((() () ()) (convert body k subst)) | |
506 | (((name . names) (sym . syms) (val . vals)) | |
9a1dfb7d | 507 | (let-fresh (kreceive klet) (rest) |
4fefc3a8 | 508 | (build-cps-term |
e6cf744a | 509 | ($letk* ((klet ($kargs (name 'rest) ((bound-var sym) rest) |
31086641 AW |
510 | ,(box-bound-var name sym |
511 | (lp names syms vals)))) | |
36527695 AW |
512 | (kreceive ($kreceive (list name) 'rest klet))) |
513 | ,(convert val kreceive subst)))))))) | |
4fefc3a8 AW |
514 | |
515 | (($ <fix> src names gensyms funs body) | |
516 | ;; Some letrecs can be contified; that happens later. | |
517 | (if (current-topbox-scope) | |
9a1dfb7d | 518 | (let-fresh () (self) |
4fefc3a8 AW |
519 | (build-cps-term |
520 | ($letrec names | |
e6cf744a | 521 | (map bound-var gensyms) |
4fefc3a8 AW |
522 | (map (lambda (fun) |
523 | (match (convert fun k subst) | |
6e422a35 | 524 | (($ $continue _ _ (and fun ($ $fun))) |
4fefc3a8 AW |
525 | fun))) |
526 | funs) | |
527 | ,(convert body k subst)))) | |
48e65b44 AW |
528 | (let ((scope-id (fresh-scope-id))) |
529 | (let-fresh (kscope) () | |
530 | (build-cps-term | |
531 | ($letk ((kscope | |
532 | ($kargs () () | |
533 | ,(parameterize ((current-topbox-scope scope-id)) | |
534 | (convert exp k subst))))) | |
535 | ,(capture-toplevel-scope src scope-id kscope))))))) | |
4fefc3a8 AW |
536 | |
537 | (($ <let-values> src exp | |
538 | ($ <lambda-case> lsrc req #f rest #f () syms body #f)) | |
e6cf744a AW |
539 | (let ((names (append req (if rest (list rest) '()))) |
540 | (bound-vars (map bound-var syms))) | |
9a1dfb7d | 541 | (let-fresh (kreceive kargs) () |
4fefc3a8 | 542 | (build-cps-term |
e6cf744a | 543 | ($letk* ((kargs ($kargs names bound-vars |
6e422a35 AW |
544 | ,(fold box-bound-var |
545 | (convert body k subst) | |
546 | names syms))) | |
36527695 AW |
547 | (kreceive ($kreceive req rest kargs))) |
548 | ,(convert exp kreceive subst)))))))) | |
4fefc3a8 AW |
549 | |
550 | (define (build-subst exp) | |
e6cf744a AW |
551 | "Compute a mapping from lexical gensyms to CPS variable indexes. CPS |
552 | uses small integers to identify variables, instead of gensyms. | |
553 | ||
554 | This subst table serves an additional purpose of mapping variables to | |
555 | replacements. The usual reason to replace one variable by another is | |
556 | assignment conversion. Default argument values is the other reason. | |
557 | ||
558 | The result is a hash table mapping symbols to substitutions (in the case | |
559 | that a variable is substituted) or to indexes. A substitution is a list | |
560 | of the form: | |
561 | ||
562 | (ORIG-INDEX SUBST-INDEX BOXED?) | |
563 | ||
564 | A true value for BOXED? indicates that the replacement variable is in a | |
565 | box. If a variable is not substituted, the mapped value is a small | |
566 | integer." | |
567 | (let ((table (make-hash-table))) | |
568 | (define (down exp) | |
569 | (match exp | |
570 | (($ <lexical-set> src name sym exp) | |
571 | (match (hashq-ref table sym) | |
572 | ((orig subst #t) #t) | |
573 | ((orig subst #f) (hashq-set! table sym (list orig subst #t))) | |
574 | ((? number? idx) (hashq-set! table sym (list idx (fresh-var) #t))))) | |
575 | (($ <lambda-case> src req opt rest kw inits gensyms body alternate) | |
576 | (fold-formals (lambda (name sym init seed) | |
577 | (hashq-set! table sym | |
578 | (if init | |
579 | (list (fresh-var) (fresh-var) #f) | |
580 | (fresh-var)))) | |
581 | #f | |
582 | (make-$arity req (or opt '()) rest | |
583 | (if kw (cdr kw) '()) (and kw (car kw))) | |
584 | gensyms | |
585 | inits)) | |
586 | (($ <let> src names gensyms vals body) | |
587 | (for-each (lambda (sym) | |
588 | (hashq-set! table sym (fresh-var))) | |
589 | gensyms)) | |
590 | (($ <fix> src names gensyms vals body) | |
591 | (for-each (lambda (sym) | |
592 | (hashq-set! table sym (fresh-var))) | |
593 | gensyms)) | |
594 | (_ #t)) | |
595 | (values)) | |
596 | (define (up exp) (values)) | |
597 | ((make-tree-il-folder) exp down up) | |
598 | table)) | |
4fefc3a8 AW |
599 | |
600 | (define (cps-convert/thunk exp) | |
9a1dfb7d | 601 | (parameterize ((label-counter 0) |
48e65b44 AW |
602 | (var-counter 0) |
603 | (scope-counter 0)) | |
9a1dfb7d AW |
604 | (let ((src (tree-il-src exp))) |
605 | (let-fresh (kinit ktail kclause kbody) (init) | |
a0329d01 AW |
606 | (build-cps-cont |
607 | (kinit ($kfun src '() init (ktail ($ktail)) | |
608 | (kclause | |
609 | ($kclause ('() '() #f '() #f) | |
610 | (kbody ($kargs () () | |
611 | ,(convert exp ktail | |
612 | (build-subst exp)))) | |
613 | ,#f))))))))) | |
4fefc3a8 AW |
614 | |
615 | (define *comp-module* (make-fluid)) | |
616 | ||
617 | (define %warning-passes | |
618 | `((unused-variable . ,unused-variable-analysis) | |
619 | (unused-toplevel . ,unused-toplevel-analysis) | |
620 | (unbound-variable . ,unbound-variable-analysis) | |
621 | (arity-mismatch . ,arity-analysis) | |
622 | (format . ,format-analysis))) | |
623 | ||
624 | (define (optimize-tree-il x e opts) | |
625 | (define warnings | |
626 | (or (and=> (memq #:warnings opts) cadr) | |
627 | '())) | |
628 | ||
629 | ;; Go through the warning passes. | |
630 | (let ((analyses (filter-map (lambda (kind) | |
631 | (assoc-ref %warning-passes kind)) | |
632 | warnings))) | |
633 | (analyze-tree analyses x e)) | |
634 | ||
635 | (optimize x e opts)) | |
636 | ||
e6cf744a | 637 | (define (canonicalize exp) |
ef58442a AW |
638 | (post-order |
639 | (lambda (exp) | |
640 | (match exp | |
e6cf744a AW |
641 | (($ <primcall> src 'vector |
642 | (and args | |
643 | ((or ($ <const>) ($ <void>) ($ <lambda>) ($ <lexical-ref>)) | |
644 | ...))) | |
645 | ;; Some macros generate calls to "vector" with like 300 | |
646 | ;; arguments. Since we eventually compile to make-vector and | |
647 | ;; vector-set!, it reduces live variable pressure to allocate the | |
648 | ;; vector first, then set values as they are produced, if we can | |
649 | ;; prove that no value can capture the continuation. (More on | |
650 | ;; that caveat here: | |
651 | ;; http://wingolog.org/archives/2013/11/02/scheme-quiz-time). | |
652 | ;; | |
653 | ;; Normally we would do this transformation in the compiler, but | |
654 | ;; it's quite tricky there and quite easy here, so hold your nose | |
655 | ;; while we drop some smelly code. | |
656 | (let ((len (length args)) | |
657 | (v (gensym "v "))) | |
658 | (make-let src | |
659 | (list 'v) | |
660 | (list v) | |
661 | (list (make-primcall src 'make-vector | |
662 | (list (make-const #f len) | |
663 | (make-const #f #f)))) | |
664 | (fold (lambda (arg n tail) | |
665 | (make-seq | |
666 | src | |
667 | (make-primcall | |
668 | src 'vector-set! | |
669 | (list (make-lexical-ref src 'v v) | |
670 | (make-const #f n) | |
671 | arg)) | |
672 | tail)) | |
673 | (make-lexical-ref src 'v v) | |
674 | (reverse args) (reverse (iota len)))))) | |
675 | ||
ef58442a AW |
676 | (($ <prompt> src escape-only? tag body |
677 | ($ <lambda> hsrc hmeta | |
678 | ($ <lambda-case> _ hreq #f hrest #f () hsyms hbody #f))) | |
679 | exp) | |
680 | ||
681 | ;; Eta-convert prompts without inline handlers. | |
682 | (($ <prompt> src escape-only? tag body handler) | |
683 | (let ((h (gensym "h ")) | |
684 | (args (gensym "args "))) | |
685 | (make-let | |
686 | src (list 'h) (list h) (list handler) | |
687 | (make-seq | |
688 | src | |
689 | (make-conditional | |
690 | src | |
691 | (make-primcall src 'procedure? (list (make-lexical-ref #f 'h h))) | |
692 | (make-void src) | |
693 | (make-primcall | |
694 | src 'scm-error | |
695 | (list | |
696 | (make-const #f 'wrong-type-arg) | |
697 | (make-const #f "call-with-prompt") | |
698 | (make-const #f "Wrong type (expecting procedure): ~S") | |
699 | (make-primcall #f 'list (list (make-lexical-ref #f 'h h))) | |
700 | (make-primcall #f 'list (list (make-lexical-ref #f 'h h)))))) | |
701 | (make-prompt | |
702 | src escape-only? tag body | |
703 | (make-lambda | |
704 | src '() | |
705 | (make-lambda-case | |
706 | src '() #f 'args #f '() (list args) | |
707 | (make-primcall | |
708 | src 'apply | |
709 | (list (make-lexical-ref #f 'h h) | |
710 | (make-lexical-ref #f 'args args))) | |
711 | #f))))))) | |
712 | (_ exp))) | |
713 | exp)) | |
714 | ||
4fefc3a8 | 715 | (define (compile-cps exp env opts) |
ef58442a | 716 | (values (cps-convert/thunk |
e6cf744a | 717 | (canonicalize (optimize-tree-il exp env opts))) |
4fefc3a8 AW |
718 | env |
719 | env)) | |
720 | ||
721 | ;;; Local Variables: | |
722 | ;;; eval: (put 'convert-arg 'scheme-indent-function 1) | |
723 | ;;; eval: (put 'convert-args 'scheme-indent-function 1) | |
724 | ;;; End: |