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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 | ;;; Compiling CPS to RTL. The result is in the RTL language, which | |
22 | ;;; happens to be an ELF image as a bytecode. | |
23 | ;;; | |
24 | ;;; Code: | |
25 | ||
26 | (define-module (language cps compile-rtl) | |
27 | #:use-module (ice-9 match) | |
28 | #:use-module (srfi srfi-1) | |
29 | #:use-module (language cps) | |
30 | #:use-module (language cps arities) | |
31 | #:use-module (language cps closure-conversion) | |
8ac8e2df | 32 | #:use-module (language cps contification) |
6e8ad823 AW |
33 | #:use-module (language cps dfg) |
34 | #:use-module (language cps primitives) | |
35 | #:use-module (language cps reify-primitives) | |
36 | #:use-module (language cps slot-allocation) | |
37 | #:use-module (system vm assembler) | |
38 | #:export (compile-rtl)) | |
39 | ||
40 | ;; TODO: Source info, local var names. Needs work in the linker and the | |
41 | ;; debugger. | |
42 | ||
43 | (define (kw-arg-ref args kw default) | |
44 | (match (memq kw args) | |
45 | ((_ val . _) val) | |
46 | (_ default))) | |
47 | ||
48 | (define (optimize exp opts) | |
49 | (define (run-pass exp pass kw default) | |
50 | (if (kw-arg-ref opts kw default) | |
51 | (pass exp) | |
52 | exp)) | |
53 | ||
54 | ;; Calls to source-to-source optimization passes go here. | |
8ac8e2df | 55 | (let* ((exp (run-pass exp contify #:contify? #t))) |
6e8ad823 AW |
56 | ;; Passes that are needed: |
57 | ;; | |
6e8ad823 AW |
58 | ;; * Abort contification: turning abort primcalls into continuation |
59 | ;; calls, and eliding prompts if possible. | |
60 | ;; | |
61 | ;; * Common subexpression elimination. Desperately needed. Requires | |
62 | ;; effects analysis. | |
63 | ;; | |
64 | ;; * Loop peeling. Unrolls the first round through a loop if the | |
65 | ;; loop has effects that CSE can work on. Requires effects | |
66 | ;; analysis. When run before CSE, loop peeling is the equivalent | |
67 | ;; of loop-invariant code motion (LICM). | |
68 | ;; | |
69 | ;; * Generic simplification pass, to be run as needed. Used to | |
70 | ;; "clean up", both on the original raw input and after specific | |
71 | ;; optimization passes. | |
72 | ||
73 | exp)) | |
74 | ||
75 | (define (visit-funs proc exp) | |
76 | (match exp | |
77 | (($ $continue _ exp) | |
78 | (visit-funs proc exp)) | |
79 | ||
80 | (($ $fun meta free body) | |
81 | (proc exp) | |
82 | (visit-funs proc body)) | |
83 | ||
84 | (($ $letk conts body) | |
85 | (visit-funs proc body) | |
86 | (for-each (lambda (cont) (visit-funs proc cont)) conts)) | |
87 | ||
88 | (($ $cont sym src ($ $kargs names syms body)) | |
89 | (visit-funs proc body)) | |
90 | ||
91 | (($ $cont sym src ($ $kclause arity body)) | |
92 | (visit-funs proc body)) | |
93 | ||
94 | (($ $cont sym src ($ $kentry self tail clauses)) | |
95 | (for-each (lambda (clause) (visit-funs proc clause)) clauses)) | |
96 | ||
97 | (_ (values)))) | |
98 | ||
99 | (define (emit-rtl-sequence asm exp allocation nlocals cont-table) | |
100 | (define (slot sym) | |
101 | (lookup-slot sym allocation)) | |
102 | ||
103 | (define (constant sym) | |
104 | (lookup-constant-value sym allocation)) | |
105 | ||
106 | (define (emit-rtl label k exp next-label) | |
107 | (define (maybe-mov dst src) | |
108 | (unless (= dst src) | |
109 | (emit-mov asm dst src))) | |
110 | ||
111 | (define (maybe-jump label) | |
112 | (unless (eq? label next-label) | |
113 | (emit-br asm label))) | |
114 | ||
115 | (define (maybe-load-constant slot src) | |
116 | (call-with-values (lambda () | |
117 | (lookup-maybe-constant-value src allocation)) | |
118 | (lambda (has-const? val) | |
119 | (and has-const? | |
120 | (begin | |
121 | (emit-load-constant asm slot val) | |
122 | #t))))) | |
123 | ||
124 | (define (emit-tail) | |
125 | ;; There are only three kinds of expressions in tail position: | |
126 | ;; tail calls, multiple-value returns, and single-value returns. | |
127 | (match exp | |
128 | (($ $call proc args) | |
129 | (for-each (match-lambda | |
130 | ((src . dst) (emit-mov asm dst src))) | |
131 | (lookup-parallel-moves label allocation)) | |
132 | (let ((tail-slots (cdr (iota (1+ (length args)))))) | |
133 | (for-each maybe-load-constant tail-slots args)) | |
134 | (emit-tail-call asm (1+ (length args)))) | |
135 | (($ $values args) | |
136 | (let ((tail-slots (cdr (iota (1+ (length args)))))) | |
137 | (for-each (match-lambda | |
138 | ((src . dst) (emit-mov asm dst src))) | |
139 | (lookup-parallel-moves label allocation)) | |
140 | (for-each maybe-load-constant tail-slots args)) | |
141 | (emit-reset-frame asm (1+ (length args))) | |
142 | (emit-return-values asm)) | |
143 | (($ $primcall 'return (arg)) | |
144 | (emit-return asm (slot arg))))) | |
145 | ||
146 | (define (emit-val sym) | |
147 | (let ((dst (slot sym))) | |
148 | (match exp | |
149 | (($ $var sym) | |
150 | (maybe-mov dst (slot sym))) | |
151 | (($ $void) | |
152 | (when dst | |
153 | (emit-load-constant asm dst *unspecified*))) | |
154 | (($ $const exp) | |
155 | (when dst | |
156 | (emit-load-constant asm dst exp))) | |
157 | (($ $fun meta () ($ $cont k)) | |
158 | (emit-load-static-procedure asm dst k)) | |
159 | (($ $fun meta free ($ $cont k)) | |
160 | (emit-make-closure asm dst k (length free))) | |
161 | (($ $call proc args) | |
162 | (let ((proc-slot (lookup-call-proc-slot label allocation)) | |
163 | (nargs (length args))) | |
164 | (or (maybe-load-constant proc-slot proc) | |
165 | (maybe-mov proc-slot (slot proc))) | |
166 | (let lp ((n (1+ proc-slot)) (args args)) | |
167 | (match args | |
168 | (() | |
169 | (emit-call asm proc-slot (+ nargs 1)) | |
170 | (emit-receive asm dst proc-slot nlocals)) | |
171 | ((arg . args) | |
172 | (or (maybe-load-constant n arg) | |
173 | (maybe-mov n (slot arg))) | |
174 | (lp (1+ n) args)))))) | |
175 | (($ $primcall 'current-module) | |
176 | (emit-current-module asm dst)) | |
177 | (($ $primcall 'cached-toplevel-box (scope name bound?)) | |
178 | (emit-cached-toplevel-box asm dst (constant scope) (constant name) | |
179 | (constant bound?))) | |
180 | (($ $primcall 'cached-module-box (mod name public? bound?)) | |
181 | (emit-cached-module-box asm dst (constant mod) (constant name) | |
182 | (constant public?) (constant bound?))) | |
183 | (($ $primcall 'resolve (name bound?)) | |
184 | (emit-resolve asm dst (constant bound?) (slot name))) | |
185 | (($ $primcall 'free-ref (closure idx)) | |
186 | (emit-free-ref asm dst (slot closure) (constant idx))) | |
187 | (($ $primcall name args) | |
188 | ;; FIXME: Inline all the cases. | |
189 | (let ((inst (prim-rtl-instruction name))) | |
190 | (emit-text asm `((,inst ,dst ,@(map slot args)))))) | |
191 | (($ $values (arg)) | |
192 | (or (maybe-load-constant dst arg) | |
8d59d55e | 193 | (maybe-mov dst (slot arg))))) |
6e8ad823 AW |
194 | (maybe-jump k))) |
195 | ||
196 | (define (emit-vals syms) | |
197 | (match exp | |
198 | (($ $primcall name args) | |
199 | (error "unimplemented primcall in values context" name)) | |
200 | (($ $values args) | |
201 | (for-each (match-lambda | |
202 | ((src . dst) (emit-mov asm dst src))) | |
203 | (lookup-parallel-moves label allocation)) | |
204 | (for-each maybe-load-constant (map slot syms) args))) | |
205 | (maybe-jump k)) | |
206 | ||
207 | (define (emit-seq) | |
208 | (match exp | |
209 | (($ $primcall 'cache-current-module! (sym scope)) | |
210 | (emit-cache-current-module! asm (slot sym) (constant scope))) | |
211 | (($ $primcall 'free-set! (closure idx value)) | |
212 | (emit-free-set! asm (slot closure) (slot value) (constant idx))) | |
213 | (($ $primcall 'box-set! (box value)) | |
214 | (emit-box-set! asm (slot box) (slot value))) | |
215 | (($ $primcall 'struct-set! (struct index value)) | |
216 | (emit-struct-set! asm (slot struct) (slot index) (slot value))) | |
217 | (($ $primcall 'vector-set! (vector index value)) | |
218 | (emit-vector-set asm (slot vector) (slot index) (slot value))) | |
219 | (($ $primcall 'set-car! (pair value)) | |
220 | (emit-set-car! asm (slot pair) (slot value))) | |
221 | (($ $primcall 'set-cdr! (pair value)) | |
222 | (emit-set-cdr! asm (slot pair) (slot value))) | |
223 | (($ $primcall 'define! (sym value)) | |
224 | (emit-define asm (slot sym) (slot value))) | |
8d59d55e AW |
225 | (($ $primcall 'unwind ()) |
226 | (emit-unwind asm)) | |
6e8ad823 AW |
227 | (($ $primcall name args) |
228 | (error "unhandled primcall in seq context" name)) | |
8d59d55e AW |
229 | (($ $values ()) #f) |
230 | (($ $prompt escape? tag handler) | |
231 | (match (lookup-cont handler cont-table) | |
232 | (($ $ktrunc ($ $arity req () rest () #f) khandler-body) | |
233 | (let ((receive-args (gensym "handler")) | |
234 | (nreq (length req)) | |
235 | (proc-slot (lookup-call-proc-slot label allocation))) | |
236 | (emit-prompt asm (slot tag) escape? proc-slot receive-args) | |
237 | (emit-br asm k) | |
238 | (emit-label asm receive-args) | |
239 | (emit-receive-values asm proc-slot (->bool rest) nreq) | |
240 | (when rest | |
241 | (emit-bind-rest asm (+ proc-slot 1 nreq))) | |
242 | (for-each (match-lambda | |
243 | ((src . dst) (emit-mov asm dst src))) | |
244 | (lookup-parallel-moves handler allocation)) | |
245 | (emit-reset-frame asm nlocals) | |
246 | (emit-br asm khandler-body)))))) | |
6e8ad823 AW |
247 | (maybe-jump k)) |
248 | ||
249 | (define (emit-test kt kf) | |
250 | (define (unary op sym) | |
251 | (cond | |
252 | ((eq? kt next-label) | |
253 | (op asm (slot sym) #t kf)) | |
254 | (else | |
255 | (op asm (slot sym) #f kt) | |
256 | (maybe-jump kf)))) | |
257 | (define (binary op a b) | |
258 | (cond | |
259 | ((eq? kt next-label) | |
260 | (op asm (slot a) (slot b) #t kf)) | |
261 | (else | |
262 | (op asm (slot a) (slot b) #f kt) | |
263 | (maybe-jump kf)))) | |
264 | (match exp | |
265 | (($ $var sym) (unary emit-br-if-true sym)) | |
266 | (($ $primcall 'null? (a)) (unary emit-br-if-null a)) | |
267 | (($ $primcall 'nil? (a)) (unary emit-br-if-nil a)) | |
268 | (($ $primcall 'pair? (a)) (unary emit-br-if-pair a)) | |
269 | (($ $primcall 'struct? (a)) (unary emit-br-if-struct a)) | |
270 | (($ $primcall 'char? (a)) (unary emit-br-if-char a)) | |
271 | ;; Add TC7 tests here | |
272 | (($ $primcall 'eq? (a b)) (binary emit-br-if-eq a b)) | |
273 | (($ $primcall 'eq? (a b)) (binary emit-br-if-eq a b)) | |
274 | (($ $primcall 'eqv? (a b)) (binary emit-br-if-eqv a b)) | |
275 | (($ $primcall 'equal? (a b)) (binary emit-br-if-equal a b)) | |
276 | (($ $primcall '< (a b)) (binary emit-br-if-< a b)) | |
277 | (($ $primcall '<= (a b)) (binary emit-br-if-<= a b)) | |
278 | (($ $primcall '= (a b)) (binary emit-br-if-= a b)) | |
279 | (($ $primcall '>= (a b)) (binary emit-br-if-<= b a)) | |
280 | (($ $primcall '> (a b)) (binary emit-br-if-< b a)))) | |
281 | ||
282 | (define (emit-trunc nreq rest? k) | |
283 | (match exp | |
284 | (($ $call proc args) | |
285 | (let ((proc-slot (lookup-call-proc-slot label allocation)) | |
286 | (nargs (length args))) | |
287 | (or (maybe-load-constant proc-slot proc) | |
288 | (maybe-mov proc-slot (slot proc))) | |
289 | (let lp ((n (1+ proc-slot)) (args args)) | |
290 | (match args | |
291 | (() | |
292 | (emit-call asm proc-slot (+ nargs 1)) | |
82f4bac4 AW |
293 | ;; FIXME: Only allow more values if there is a rest arg. |
294 | ;; Express values truncation by the presence of an | |
295 | ;; unused rest arg instead of implicitly. | |
296 | (emit-receive-values asm proc-slot #t nreq) | |
6e8ad823 AW |
297 | (when rest? |
298 | (emit-bind-rest asm (+ proc-slot 1 nreq))) | |
299 | (for-each (match-lambda | |
300 | ((src . dst) (emit-mov asm dst src))) | |
301 | (lookup-parallel-moves label allocation)) | |
302 | (emit-reset-frame asm nlocals)) | |
303 | ((arg . args) | |
304 | (or (maybe-load-constant n arg) | |
305 | (maybe-mov n (slot arg))) | |
306 | (lp (1+ n) args))))))) | |
307 | (maybe-jump k)) | |
308 | ||
309 | (match (lookup-cont k cont-table) | |
310 | (($ $ktail) (emit-tail)) | |
311 | (($ $kargs (name) (sym)) (emit-val sym)) | |
312 | (($ $kargs () ()) (emit-seq)) | |
313 | (($ $kargs names syms) (emit-vals syms)) | |
314 | (($ $kargs (name) (sym)) (emit-val sym)) | |
315 | (($ $kif kt kf) (emit-test kt kf)) | |
316 | (($ $ktrunc ($ $arity req () rest () #f) k) | |
317 | (emit-trunc (length req) (and rest #t) k)))) | |
318 | ||
319 | (define (collect-exps k src cont tail) | |
320 | (define (find-exp k src term) | |
321 | (match term | |
322 | (($ $continue exp-k exp) | |
323 | (cons (list k src exp-k exp) tail)) | |
324 | (($ $letk conts body) | |
325 | (find-exp k src body)))) | |
326 | (match cont | |
327 | (($ $kargs names syms body) | |
328 | (find-exp k src body)) | |
329 | (_ tail))) | |
330 | ||
331 | (let lp ((exps (reverse (fold-local-conts collect-exps '() exp)))) | |
332 | (match exps | |
333 | (() #t) | |
334 | (((k src exp-k exp) . exps) | |
335 | (let ((next-label (match exps | |
336 | (((k . _) . _) k) | |
337 | (() #f)))) | |
338 | (emit-label asm k) | |
e675e9bd AW |
339 | (when src |
340 | (emit-source asm src)) | |
6e8ad823 AW |
341 | (emit-rtl k exp-k exp next-label) |
342 | (lp exps)))))) | |
343 | ||
344 | (define (compile-fun f asm) | |
345 | (let ((allocation (allocate-slots f)) | |
346 | (cont-table (match f | |
347 | (($ $fun meta free body) | |
348 | (build-local-cont-table body))))) | |
349 | (define (emit-fun-clause clause alternate) | |
350 | (match clause | |
351 | (($ $cont k src | |
352 | ($ $kclause ($ $arity req opt rest kw allow-other-keys?) | |
353 | body)) | |
354 | (let ((kw-indices (map (match-lambda | |
355 | ((key name sym) | |
356 | (cons key (lookup-slot sym allocation)))) | |
357 | kw)) | |
358 | (nlocals (lookup-nlocals k allocation))) | |
359 | (emit-label asm k) | |
e675e9bd AW |
360 | (when src |
361 | (emit-source asm src)) | |
6e8ad823 AW |
362 | (emit-begin-kw-arity asm req opt rest kw-indices allow-other-keys? |
363 | nlocals alternate) | |
364 | (emit-rtl-sequence asm body allocation nlocals cont-table) | |
365 | (emit-end-arity asm))))) | |
366 | ||
367 | (define (emit-fun-clauses clauses) | |
368 | (match clauses | |
369 | ((clause . clauses) | |
370 | (let ((kalternate (match clauses | |
371 | (() #f) | |
372 | ((($ $cont k) . _) k)))) | |
373 | (emit-fun-clause clause kalternate) | |
374 | (when kalternate | |
375 | (emit-fun-clauses clauses)))))) | |
376 | ||
377 | (match f | |
378 | (($ $fun meta free ($ $cont k src ($ $kentry self tail clauses))) | |
379 | (emit-begin-program asm k (or meta '())) | |
e675e9bd AW |
380 | (when src |
381 | (emit-source asm src)) | |
6e8ad823 AW |
382 | (emit-fun-clauses clauses) |
383 | (emit-end-program asm))))) | |
384 | ||
385 | (define (compile-rtl exp env opts) | |
386 | (let* ((exp (fix-arities exp)) | |
387 | (exp (optimize exp opts)) | |
388 | (exp (convert-closures exp)) | |
389 | (exp (reify-primitives exp)) | |
390 | (asm (make-assembler))) | |
391 | (visit-funs (lambda (fun) | |
392 | (compile-fun fun asm)) | |
393 | exp) | |
394 | (values (link-assembly asm #:page-aligned? (kw-arg-ref opts #:to-file? #f)) | |
395 | env | |
396 | env))) |