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6e8ad823 AW |
1 | ;;; Continuation-passing style (CPS) intermediate language (IL) |
2 | ||
a9ec16f9 | 3 | ;; Copyright (C) 2013, 2014, 2015 Free Software Foundation, Inc. |
6e8ad823 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 | ;;; Many passes rely on a local or global static analysis of a function. | |
22 | ;;; This module implements a simple data-flow graph (DFG) analysis, | |
23 | ;;; tracking the definitions and uses of variables and continuations. | |
f22979db | 24 | ;;; It also builds a table of continuations and scope links, to be able |
6e8ad823 AW |
25 | ;;; to easily determine if one continuation is in the scope of another, |
26 | ;;; and to get to the expression inside a continuation. | |
27 | ;;; | |
28 | ;;; Note that the data-flow graph of continuation labels is a | |
29 | ;;; control-flow graph. | |
30 | ;;; | |
31 | ;;; We currently don't expose details of the DFG type outside this | |
32 | ;;; module, preferring to only expose accessors. That may change in the | |
33 | ;;; future but it seems to work for now. | |
34 | ;;; | |
35 | ;;; Code: | |
36 | ||
37 | (define-module (language cps dfg) | |
38 | #:use-module (ice-9 match) | |
fb512cac | 39 | #:use-module (ice-9 format) |
6e8ad823 AW |
40 | #:use-module (srfi srfi-1) |
41 | #:use-module (srfi srfi-9) | |
42 | #:use-module (srfi srfi-26) | |
43 | #:use-module (language cps) | |
e9808c14 | 44 | #:use-module (language cps intset) |
6e8ad823 | 45 | #:export (build-cont-table |
6e8ad823 AW |
46 | lookup-cont |
47 | ||
48 | compute-dfg | |
49 | dfg-cont-table | |
a8430ab1 AW |
50 | dfg-min-label |
51 | dfg-label-count | |
52 | dfg-min-var | |
53 | dfg-var-count | |
3e1b97c1 | 54 | with-fresh-name-state-from-dfg |
6e8ad823 AW |
55 | lookup-def |
56 | lookup-uses | |
f22979db AW |
57 | lookup-predecessors |
58 | lookup-successors | |
c8ad7426 | 59 | lookup-block-scope |
6e8ad823 AW |
60 | find-call |
61 | call-expression | |
62 | find-expression | |
63 | find-defining-expression | |
64 | find-constant-value | |
f22979db | 65 | continuation-bound-in? |
d51fb1e6 | 66 | variable-free-in? |
6e8ad823 | 67 | constant-needs-allocation? |
e636f424 | 68 | control-point? |
db11440d AW |
69 | lookup-bound-syms |
70 | ||
38c7bd0e AW |
71 | compute-idoms |
72 | compute-dom-edges | |
73 | ||
db11440d AW |
74 | ;; Data flow analysis. |
75 | compute-live-variables | |
76 | dfa-k-idx dfa-k-sym dfa-k-count dfa-k-in dfa-k-out | |
29619661 | 77 | dfa-var-idx dfa-var-sym dfa-var-count |
db11440d | 78 | print-dfa)) |
6e8ad823 | 79 | |
48c2a539 AW |
80 | ;; These definitions are here because currently we don't do cross-module |
81 | ;; inlining. They can be removed once that restriction is gone. | |
82 | (define-inlinable (for-each f l) | |
83 | (unless (list? l) | |
84 | (scm-error 'wrong-type-arg "for-each" "Not a list: ~S" (list l) #f)) | |
85 | (let for-each1 ((l l)) | |
86 | (unless (null? l) | |
87 | (f (car l)) | |
88 | (for-each1 (cdr l))))) | |
89 | ||
90 | (define-inlinable (for-each/2 f l1 l2) | |
91 | (unless (= (length l1) (length l2)) | |
92 | (scm-error 'wrong-type-arg "for-each" "List of wrong length: ~S" | |
93 | (list l2) #f)) | |
94 | (let for-each2 ((l1 l1) (l2 l2)) | |
95 | (unless (null? l1) | |
96 | (f (car l1) (car l2)) | |
97 | (for-each2 (cdr l1) (cdr l2))))) | |
98 | ||
6e8ad823 | 99 | (define (build-cont-table fun) |
fbdb69b2 AW |
100 | (let ((max-k (fold-conts (lambda (k cont max-k) (max k max-k)) |
101 | -1 fun))) | |
102 | (fold-conts (lambda (k cont table) | |
103 | (vector-set! table k cont) | |
104 | table) | |
105 | (make-vector (1+ max-k) #f) | |
106 | fun))) | |
107 | ||
6e8ad823 AW |
108 | ;; Data-flow graph for CPS: both for values and continuations. |
109 | (define-record-type $dfg | |
4bf757b8 | 110 | (make-dfg conts preds defs uses scopes scope-levels |
3e1b97c1 AW |
111 | min-label max-label label-count |
112 | min-var max-var var-count) | |
6e8ad823 | 113 | dfg? |
59258f7c | 114 | ;; vector of label -> $kargs, etc |
6e8ad823 | 115 | (conts dfg-cont-table) |
5fc40391 | 116 | ;; vector of label -> (pred-label ...) |
21d6d183 | 117 | (preds dfg-preds) |
5fc40391 | 118 | ;; vector of var -> def-label |
98c5b69f | 119 | (defs dfg-defs) |
5fc40391 | 120 | ;; vector of var -> (use-label ...) |
98c5b69f | 121 | (uses dfg-uses) |
5fc40391 AW |
122 | ;; vector of label -> label |
123 | (scopes dfg-scopes) | |
124 | ;; vector of label -> int | |
125 | (scope-levels dfg-scope-levels) | |
5e897908 AW |
126 | |
127 | (min-label dfg-min-label) | |
3e1b97c1 | 128 | (max-label dfg-max-label) |
a8430ab1 | 129 | (label-count dfg-label-count) |
3e1b97c1 | 130 | |
5e897908 | 131 | (min-var dfg-min-var) |
3e1b97c1 | 132 | (max-var dfg-max-var) |
a8430ab1 | 133 | (var-count dfg-var-count)) |
6e8ad823 | 134 | |
9002277d AW |
135 | (define-inlinable (vector-push! vec idx val) |
136 | (let ((v vec) (i idx)) | |
137 | (vector-set! v i (cons val (vector-ref v i))))) | |
138 | ||
16af91e8 | 139 | (define (compute-reachable dfg min-label label-count) |
4ec3ded0 | 140 | "Compute and return the continuations that may be reached if flow |
5ded8498 | 141 | reaches a continuation N. Returns a vector of intsets, whose first |
4ec3ded0 | 142 | index corresponds to MIN-LABEL, and so on." |
e9808c14 | 143 | (let (;; Vector of intsets, indicating that continuation N can |
16af91e8 AW |
144 | ;; reach a set M... |
145 | (reachable (make-vector label-count #f))) | |
146 | ||
147 | (define (label->idx label) (- label min-label)) | |
9002277d | 148 | |
4ec3ded0 | 149 | ;; Iterate labels backwards, to converge quickly. |
e9808c14 AW |
150 | (let lp ((label (+ min-label label-count)) (changed? #f)) |
151 | (cond | |
152 | ((= label min-label) | |
153 | (if changed? | |
154 | (lp (+ min-label label-count) #f) | |
155 | reachable)) | |
156 | (else | |
157 | (let* ((label (1- label)) | |
158 | (idx (label->idx label)) | |
159 | (old (vector-ref reachable idx)) | |
160 | (new (fold (lambda (succ set) | |
161 | (cond | |
162 | ((vector-ref reachable (label->idx succ)) | |
163 | => (lambda (succ-set) | |
164 | (intset-union set succ-set))) | |
165 | (else set))) | |
166 | (or (vector-ref reachable idx) | |
167 | (intset-add empty-intset label)) | |
168 | (visit-cont-successors list | |
169 | (lookup-cont label dfg))))) | |
170 | (cond | |
171 | ((eq? old new) | |
172 | (lp label changed?)) | |
173 | (else | |
174 | (vector-set! reachable idx new) | |
175 | (lp label #t))))))))) | |
9002277d | 176 | |
16af91e8 AW |
177 | (define (find-prompts dfg min-label label-count) |
178 | "Find the prompts in DFG between MIN-LABEL and MIN-LABEL + | |
179 | LABEL-COUNT, and return them as a list of PROMPT-LABEL, HANDLER-LABEL | |
180 | pairs." | |
181 | (let lp ((label min-label) (prompts '())) | |
9002277d | 182 | (cond |
16af91e8 | 183 | ((= label (+ min-label label-count)) |
9002277d AW |
184 | (reverse prompts)) |
185 | (else | |
16af91e8 | 186 | (match (lookup-cont label dfg) |
9002277d AW |
187 | (($ $kargs names syms body) |
188 | (match (find-expression body) | |
189 | (($ $prompt escape? tag handler) | |
16af91e8 AW |
190 | (lp (1+ label) (acons label handler prompts))) |
191 | (_ (lp (1+ label) prompts)))) | |
192 | (_ (lp (1+ label) prompts))))))) | |
9002277d | 193 | |
16af91e8 | 194 | (define (compute-interval reachable min-label label-count start end) |
9002277d | 195 | "Compute and return the set of continuations that may be reached from |
e9808c14 AW |
196 | START, inclusive, but not reached by END, exclusive. Returns an |
197 | intset." | |
198 | (intset-subtract (vector-ref reachable (- start min-label)) | |
199 | (vector-ref reachable (- end min-label)))) | |
9002277d | 200 | |
16af91e8 AW |
201 | (define (find-prompt-bodies dfg min-label label-count) |
202 | "Find all the prompts in DFG from the LABEL-COUNT continuations | |
203 | starting at MIN-LABEL, and compute the set of continuations that is | |
204 | reachable from the prompt bodies but not from the corresponding handler. | |
e9808c14 AW |
205 | Returns a list of PROMPT, HANDLER, BODY lists, where the BODY is an |
206 | intset." | |
16af91e8 | 207 | (match (find-prompts dfg min-label label-count) |
9002277d AW |
208 | (() '()) |
209 | (((prompt . handler) ...) | |
16af91e8 | 210 | (let ((reachable (compute-reachable dfg min-label label-count))) |
9002277d AW |
211 | (map (lambda (prompt handler) |
212 | ;; FIXME: It isn't correct to use all continuations | |
213 | ;; reachable from the prompt, because that includes | |
214 | ;; continuations outside the prompt body. This point is | |
215 | ;; moot if the handler's control flow joins with the the | |
216 | ;; body, as is usually but not always the case. | |
217 | ;; | |
218 | ;; One counter-example is when the handler contifies an | |
219 | ;; infinite loop; in that case we compute a too-large | |
16af91e8 AW |
220 | ;; prompt body. This error is currently innocuous, but we |
221 | ;; should fix it at some point. | |
9002277d AW |
222 | ;; |
223 | ;; The fix is to end the body at the corresponding "pop" | |
224 | ;; primcall, if any. | |
16af91e8 AW |
225 | (let ((body (compute-interval reachable min-label label-count |
226 | prompt handler))) | |
9002277d AW |
227 | (list prompt handler body))) |
228 | prompt handler))))) | |
229 | ||
16af91e8 | 230 | (define* (visit-prompt-control-flow dfg min-label label-count f #:key complete?) |
4ec3ded0 AW |
231 | "For all prompts in DFG in the range [MIN-LABEL, MIN-LABEL + |
232 | LABEL-COUNT), invoke F with arguments PROMPT, HANDLER, and BODY for each | |
233 | body continuation in the prompt." | |
16af91e8 AW |
234 | (define (label->idx label) (- label min-label)) |
235 | (define (idx->label idx) (+ idx min-label)) | |
9002277d AW |
236 | (for-each |
237 | (match-lambda | |
238 | ((prompt handler body) | |
e9808c14 | 239 | (define (out-or-back-edge? label) |
9002277d AW |
240 | ;; Most uses of visit-prompt-control-flow don't need every body |
241 | ;; continuation, and would be happy getting called only for | |
242 | ;; continuations that postdominate the rest of the body. Unless | |
243 | ;; you pass #:complete? #t, we only invoke F on continuations | |
244 | ;; that can leave the body, or on back-edges in loops. | |
245 | ;; | |
246 | ;; You would think that looking for the final "pop" primcall | |
247 | ;; would be sufficient, but that is incorrect; it's possible for | |
248 | ;; a loop in the prompt body to be contified, and that loop need | |
249 | ;; not continue to the pop if it never terminates. The pop could | |
250 | ;; even be removed by DCE, in that case. | |
251 | (or-map (lambda (succ) | |
e9808c14 AW |
252 | (or (not (intset-ref body succ)) |
253 | (<= succ label))) | |
254 | (lookup-successors label dfg))) | |
255 | (let lp ((label min-label)) | |
256 | (let ((label (intset-next body label))) | |
257 | (when label | |
258 | (when (or complete? (out-or-back-edge? label)) | |
259 | (f prompt handler label)) | |
260 | (lp (1+ label))))))) | |
16af91e8 AW |
261 | (find-prompt-bodies dfg min-label label-count))) |
262 | ||
a7324faf AW |
263 | (define (analyze-reverse-control-flow fun dfg min-label label-count) |
264 | (define (compute-reverse-control-flow-order ktail dfg) | |
21a528fd | 265 | (let ((label-map (make-vector label-count #f)) |
16af91e8 AW |
266 | (next -1)) |
267 | (define (label->idx label) (- label min-label)) | |
268 | (define (idx->label idx) (+ idx min-label)) | |
269 | ||
270 | (let visit ((k ktail)) | |
271 | ;; Mark this label as visited. | |
272 | (vector-set! label-map (label->idx k) #t) | |
273 | (for-each (lambda (k) | |
274 | ;; Visit predecessors unless they are already visited. | |
275 | (unless (vector-ref label-map (label->idx k)) | |
276 | (visit k))) | |
277 | (lookup-predecessors k dfg)) | |
278 | ;; Add to reverse post-order chain. | |
279 | (vector-set! label-map (label->idx k) next) | |
280 | (set! next k)) | |
281 | ||
282 | (let lp ((n 0) (head next)) | |
283 | (if (< head 0) | |
284 | ;; Add nodes that are not reachable from the tail. | |
285 | (let lp ((n n) (m label-count)) | |
286 | (unless (= n label-count) | |
287 | (let find-unvisited ((m (1- m))) | |
288 | (if (vector-ref label-map m) | |
289 | (find-unvisited (1- m)) | |
290 | (begin | |
291 | (vector-set! label-map m n) | |
292 | (lp (1+ n) m)))))) | |
293 | ;; Pop the head off the chain, give it its | |
294 | ;; reverse-post-order numbering, and continue. | |
295 | (let ((next (vector-ref label-map (label->idx head)))) | |
296 | (vector-set! label-map (label->idx head) n) | |
297 | (lp (1+ n) next)))) | |
298 | ||
21a528fd | 299 | label-map)) |
16af91e8 | 300 | |
a7324faf | 301 | (define (convert-successors k-map) |
16af91e8 AW |
302 | (define (idx->label idx) (+ idx min-label)) |
303 | (define (renumber label) | |
304 | (vector-ref k-map (- label min-label))) | |
305 | (let ((succs (make-vector (vector-length k-map) #f))) | |
306 | (let lp ((n 0)) | |
307 | (when (< n (vector-length succs)) | |
308 | (vector-set! succs (vector-ref k-map n) | |
309 | (map renumber | |
310 | (lookup-successors (idx->label n) dfg))) | |
311 | (lp (1+ n)))) | |
312 | succs)) | |
313 | ||
a7324faf | 314 | (match fun |
6bc36ca5 | 315 | (($ $cont kfun ($ $kfun src meta self ($ $cont ktail tail))) |
21a528fd AW |
316 | (let* ((k-map (compute-reverse-control-flow-order ktail dfg)) |
317 | (succs (convert-successors k-map))) | |
318 | ;; Any expression in the prompt body could cause an abort to | |
319 | ;; the handler. This code adds links from every block in the | |
320 | ;; prompt body to the handler. This causes all values used | |
321 | ;; by the handler to be seen as live in the prompt body, as | |
322 | ;; indeed they are. | |
323 | (visit-prompt-control-flow | |
324 | dfg min-label label-count | |
325 | (lambda (prompt handler body) | |
326 | (define (renumber label) | |
327 | (vector-ref k-map (- label min-label))) | |
328 | (vector-push! succs (renumber body) (renumber handler)))) | |
329 | ||
330 | (values k-map succs))))) | |
dda5fd94 | 331 | |
38c7bd0e AW |
332 | (define (compute-idoms dfg min-label label-count) |
333 | (define preds (dfg-preds dfg)) | |
4ec3ded0 AW |
334 | (define (label->idx label) (- label min-label)) |
335 | (define (idx->label idx) (+ idx min-label)) | |
38c7bd0e AW |
336 | (define (idx->dfg-idx idx) (- (idx->label idx) (dfg-min-label dfg))) |
337 | (let ((idoms (make-vector label-count #f))) | |
3aee6cfd AW |
338 | (define (common-idom d0 d1) |
339 | ;; We exploit the fact that a reverse post-order is a topological | |
340 | ;; sort, and so the idom of a node is always numerically less than | |
341 | ;; the node itself. | |
342 | (cond | |
343 | ((= d0 d1) d0) | |
38c7bd0e AW |
344 | ((< d0 d1) (common-idom d0 (vector-ref idoms (label->idx d1)))) |
345 | (else (common-idom (vector-ref idoms (label->idx d0)) d1)))) | |
3aee6cfd | 346 | (define (compute-idom preds) |
38c7bd0e AW |
347 | (define (has-idom? pred) |
348 | (vector-ref idoms (label->idx pred))) | |
3aee6cfd | 349 | (match preds |
38c7bd0e | 350 | (() min-label) |
3aee6cfd | 351 | ((pred . preds) |
38c7bd0e AW |
352 | (if (has-idom? pred) |
353 | (let lp ((idom pred) (preds preds)) | |
354 | (match preds | |
355 | (() idom) | |
356 | ((pred . preds) | |
357 | (lp (if (has-idom? pred) | |
358 | (common-idom idom pred) | |
359 | idom) | |
360 | preds)))) | |
361 | (compute-idom preds))))) | |
3aee6cfd AW |
362 | ;; This is the iterative O(n^2) fixpoint algorithm, originally from |
363 | ;; Allen and Cocke ("Graph-theoretic constructs for program flow | |
364 | ;; analysis", 1972). See the discussion in Cooper, Harvey, and | |
365 | ;; Kennedy's "A Simple, Fast Dominance Algorithm", 2001. | |
366 | (let iterate ((n 0) (changed? #f)) | |
367 | (cond | |
4ec3ded0 | 368 | ((< n label-count) |
3aee6cfd | 369 | (let ((idom (vector-ref idoms n)) |
38c7bd0e | 370 | (idom* (compute-idom (vector-ref preds (idx->dfg-idx n))))) |
3aee6cfd AW |
371 | (cond |
372 | ((eqv? idom idom*) | |
373 | (iterate (1+ n) changed?)) | |
374 | (else | |
375 | (vector-set! idoms n idom*) | |
376 | (iterate (1+ n) #t))))) | |
377 | (changed? | |
378 | (iterate 0 #f)) | |
366eb4d7 AW |
379 | (else idoms))))) |
380 | ||
96b8027c AW |
381 | ;; Compute a vector containing, for each node, a list of the nodes that |
382 | ;; it immediately dominates. These are the "D" edges in the DJ tree. | |
38c7bd0e AW |
383 | (define (compute-dom-edges idoms min-label) |
384 | (define (label->idx label) (- label min-label)) | |
385 | (define (idx->label idx) (+ idx min-label)) | |
96b8027c AW |
386 | (let ((doms (make-vector (vector-length idoms) '()))) |
387 | (let lp ((n 0)) | |
388 | (when (< n (vector-length idoms)) | |
389 | (let ((idom (vector-ref idoms n))) | |
38c7bd0e | 390 | (vector-push! doms (label->idx idom) (idx->label n))) |
96b8027c AW |
391 | (lp (1+ n)))) |
392 | doms)) | |
393 | ||
38c7bd0e AW |
394 | ;; There used to be some loop detection code here, but it bitrotted. |
395 | ;; We'll need it again eventually but for now it can be found in the git | |
396 | ;; history. | |
db11440d | 397 | |
db11440d AW |
398 | ;; Data-flow analysis. |
399 | (define-record-type $dfa | |
21a528fd | 400 | (make-dfa min-label min-var var-count in out) |
db11440d | 401 | dfa? |
21a528fd | 402 | ;; Minimum label in this function. |
a57f6e1e | 403 | (min-label dfa-min-label) |
7c4977e6 AW |
404 | ;; Minimum var in this function. |
405 | (min-var dfa-min-var) | |
21a528fd | 406 | ;; Var count in this function. |
7c4977e6 | 407 | (var-count dfa-var-count) |
5ded8498 | 408 | ;; Vector of k-idx -> intset |
db11440d | 409 | (in dfa-in) |
5ded8498 | 410 | ;; Vector of k-idx -> intset |
db11440d AW |
411 | (out dfa-out)) |
412 | ||
413 | (define (dfa-k-idx dfa k) | |
21a528fd | 414 | (- k (dfa-min-label dfa))) |
db11440d AW |
415 | |
416 | (define (dfa-k-sym dfa idx) | |
21a528fd | 417 | (+ idx (dfa-min-label dfa))) |
db11440d AW |
418 | |
419 | (define (dfa-k-count dfa) | |
21a528fd | 420 | (vector-length (dfa-in dfa))) |
db11440d AW |
421 | |
422 | (define (dfa-var-idx dfa var) | |
7c4977e6 AW |
423 | (let ((idx (- var (dfa-min-var dfa)))) |
424 | (unless (< -1 idx (dfa-var-count dfa)) | |
425 | (error "var out of range" var)) | |
426 | idx)) | |
db11440d | 427 | |
db11440d | 428 | (define (dfa-var-sym dfa idx) |
7c4977e6 AW |
429 | (unless (< -1 idx (dfa-var-count dfa)) |
430 | (error "idx out of range" idx)) | |
431 | (+ idx (dfa-min-var dfa))) | |
db11440d AW |
432 | |
433 | (define (dfa-k-in dfa idx) | |
434 | (vector-ref (dfa-in dfa) idx)) | |
435 | ||
436 | (define (dfa-k-out dfa idx) | |
437 | (vector-ref (dfa-out dfa) idx)) | |
438 | ||
5bff3125 | 439 | (define (compute-live-variables fun dfg) |
5ded8498 AW |
440 | ;; Compute the maximum fixed point of the data-flow constraint problem. |
441 | ;; | |
442 | ;; This always completes, as the graph is finite and the in and out sets | |
443 | ;; are complete semi-lattices. If the graph is reducible and the blocks | |
444 | ;; are sorted in reverse post-order, this completes in a maximum of LC + | |
445 | ;; 2 iterations, where LC is the loop connectedness number. See Hecht | |
446 | ;; and Ullman, "Analysis of a simple algorithm for global flow | |
447 | ;; problems", POPL 1973, or the recent summary in "Notes on graph | |
448 | ;; algorithms used in optimizing compilers", Offner 2013. | |
449 | (define (compute-maximum-fixed-point preds inv outv killv genv) | |
450 | (define (fold f seed l) | |
451 | (if (null? l) seed (fold f (f (car l) seed) (cdr l)))) | |
452 | (let lp ((n 0) (changed? #f)) | |
453 | (cond | |
454 | ((< n (vector-length preds)) | |
455 | (let* ((in (vector-ref inv n)) | |
456 | (in* (or | |
457 | (fold (lambda (pred set) | |
458 | (cond | |
459 | ((vector-ref outv pred) | |
460 | => (lambda (out) | |
461 | (if set | |
462 | (intset-union set out) | |
463 | out))) | |
464 | (else set))) | |
465 | in | |
466 | (vector-ref preds n)) | |
467 | empty-intset))) | |
468 | (if (eq? in in*) | |
469 | (lp (1+ n) changed?) | |
470 | (let ((out* (fold (lambda (gen set) | |
471 | (intset-add set gen)) | |
472 | (fold (lambda (kill set) | |
473 | (intset-remove set kill)) | |
474 | in* | |
475 | (vector-ref killv n)) | |
476 | (vector-ref genv n)))) | |
477 | (vector-set! inv n in*) | |
478 | (vector-set! outv n out*) | |
479 | (lp (1+ n) #t))))) | |
480 | (changed? | |
481 | (lp 0 #f))))) | |
482 | ||
7c4977e6 AW |
483 | (unless (and (= (vector-length (dfg-uses dfg)) (dfg-var-count dfg)) |
484 | (= (vector-length (dfg-cont-table dfg)) (dfg-label-count dfg))) | |
485 | (error "function needs renumbering")) | |
a7324faf AW |
486 | (let* ((min-label (dfg-min-label dfg)) |
487 | (nlabels (dfg-label-count dfg)) | |
488 | (min-var (dfg-min-var dfg)) | |
a8430ab1 | 489 | (nvars (dfg-var-count dfg)) |
a7324faf AW |
490 | (usev (make-vector nlabels '())) |
491 | (defv (make-vector nlabels '())) | |
492 | (live-in (make-vector nlabels #f)) | |
493 | (live-out (make-vector nlabels #f))) | |
494 | (call-with-values | |
495 | (lambda () | |
496 | (analyze-reverse-control-flow fun dfg min-label nlabels)) | |
21a528fd | 497 | (lambda (k-map succs) |
a7324faf AW |
498 | (define (var->idx var) (- var min-var)) |
499 | (define (idx->var idx) (+ idx min-var)) | |
500 | (define (label->idx label) | |
501 | (vector-ref k-map (- label min-label))) | |
502 | ||
503 | ;; Initialize defv and usev. | |
504 | (let ((defs (dfg-defs dfg)) | |
505 | (uses (dfg-uses dfg))) | |
506 | (let lp ((n 0)) | |
507 | (when (< n (vector-length defs)) | |
508 | (let ((def (vector-ref defs n))) | |
509 | (unless def | |
510 | (error "internal error -- var array not packed")) | |
511 | (for-each (lambda (def) | |
512 | (vector-push! defv (label->idx def) n)) | |
513 | (lookup-predecessors def dfg)) | |
514 | (for-each (lambda (use) | |
515 | (vector-push! usev (label->idx use) n)) | |
516 | (vector-ref uses n)) | |
517 | (lp (1+ n)))))) | |
518 | ||
a7324faf AW |
519 | ;; Liveness is a reverse data-flow problem, so we give |
520 | ;; compute-maximum-fixed-point a reversed graph, swapping in for | |
521 | ;; out, usev for defv, and using successors instead of | |
522 | ;; predecessors. Continuation 0 is ktail. | |
5ded8498 | 523 | (compute-maximum-fixed-point succs live-out live-in defv usev) |
a7324faf | 524 | |
21a528fd AW |
525 | ;; Now rewrite the live-in and live-out sets to be indexed by |
526 | ;; (LABEL - MIN-LABEL). | |
527 | (let ((live-in* (make-vector nlabels #f)) | |
528 | (live-out* (make-vector nlabels #f))) | |
529 | (let lp ((idx 0)) | |
530 | (when (< idx nlabels) | |
531 | (let ((dfa-idx (vector-ref k-map idx))) | |
532 | (vector-set! live-in* idx (vector-ref live-in dfa-idx)) | |
533 | (vector-set! live-out* idx (vector-ref live-out dfa-idx)) | |
534 | (lp (1+ idx))))) | |
535 | ||
536 | (make-dfa min-label min-var nvars live-in* live-out*)))))) | |
db11440d AW |
537 | |
538 | (define (print-dfa dfa) | |
539 | (match dfa | |
21a528fd | 540 | (($ $dfa min-label min-var var-count in out) |
db11440d AW |
541 | (define (print-var-set bv) |
542 | (let lp ((n 0)) | |
5ded8498 | 543 | (let ((n (intset-next bv n))) |
db11440d | 544 | (when n |
7c4977e6 | 545 | (format #t " ~A" (+ n min-var)) |
db11440d AW |
546 | (lp (1+ n)))))) |
547 | (let lp ((n 0)) | |
21a528fd AW |
548 | (when (< n (vector-length in)) |
549 | (format #t "~A:\n" (+ n min-label)) | |
db11440d AW |
550 | (format #t " in:") |
551 | (print-var-set (vector-ref in n)) | |
552 | (newline) | |
553 | (format #t " out:") | |
554 | (print-var-set (vector-ref out n)) | |
555 | (newline) | |
556 | (lp (1+ n))))))) | |
557 | ||
5e897908 AW |
558 | (define (compute-label-and-var-ranges fun global?) |
559 | (define (min* a b) | |
560 | (if b (min a b) a)) | |
405805fb AW |
561 | (define-syntax-rule (do-fold make-cont-folder) |
562 | ((make-cont-folder min-label max-label label-count | |
545274a0 AW |
563 | min-var max-var var-count) |
564 | (lambda (label cont | |
565 | min-label max-label label-count | |
566 | min-var max-var var-count) | |
567 | (let ((min-label (min* label min-label)) | |
568 | (max-label (max label max-label))) | |
569 | (define (visit-letrec body min-var max-var var-count) | |
570 | (match body | |
571 | (($ $letk conts body) | |
572 | (visit-letrec body min-var max-var var-count)) | |
573 | (($ $letrec names vars funs body) | |
574 | (visit-letrec body | |
575 | (cond (min-var (fold min min-var vars)) | |
576 | ((pair? vars) (fold min (car vars) (cdr vars))) | |
577 | (else min-var)) | |
578 | (fold max max-var vars) | |
579 | (+ var-count (length vars)))) | |
580 | (($ $continue) (values min-var max-var var-count)))) | |
581 | (match cont | |
582 | (($ $kargs names vars body) | |
583 | (call-with-values | |
584 | (lambda () | |
585 | (if global? | |
586 | (visit-letrec body min-var max-var var-count) | |
587 | (values min-var max-var var-count))) | |
588 | (lambda (min-var max-var var-count) | |
589 | (values min-label max-label (1+ label-count) | |
590 | (cond (min-var (fold min min-var vars)) | |
591 | ((pair? vars) (fold min (car vars) (cdr vars))) | |
592 | (else min-var)) | |
593 | (fold max max-var vars) | |
594 | (+ var-count (length vars)))))) | |
8320f504 | 595 | (($ $kfun src meta self) |
545274a0 AW |
596 | (values min-label max-label (1+ label-count) |
597 | (min* self min-var) (max self max-var) (1+ var-count))) | |
598 | (_ (values min-label max-label (1+ label-count) | |
599 | min-var max-var var-count))))) | |
600 | fun | |
601 | #f -1 0 #f -1 0)) | |
602 | (if global? | |
405805fb AW |
603 | (do-fold make-global-cont-folder) |
604 | (do-fold make-local-cont-folder))) | |
5e897908 | 605 | |
6e8ad823 | 606 | (define* (compute-dfg fun #:key (global? #t)) |
a16af113 AW |
607 | (call-with-values (lambda () (compute-label-and-var-ranges fun global?)) |
608 | (lambda (min-label max-label label-count min-var max-var var-count) | |
609 | (when (or (zero? label-count) (zero? var-count)) | |
610 | (error "internal error (no vars or labels for fun?)")) | |
611 | (let* ((nlabels (- (1+ max-label) min-label)) | |
612 | (nvars (- (1+ max-var) min-var)) | |
613 | (conts (make-vector nlabels #f)) | |
614 | (preds (make-vector nlabels '())) | |
615 | (defs (make-vector nvars #f)) | |
616 | (uses (make-vector nvars '())) | |
617 | (scopes (make-vector nlabels #f)) | |
618 | (scope-levels (make-vector nlabels #f))) | |
619 | (define (var->idx var) (- var min-var)) | |
620 | (define (label->idx label) (- label min-label)) | |
621 | ||
622 | (define (add-def! var def-k) | |
623 | (vector-set! defs (var->idx var) def-k)) | |
624 | (define (add-use! var use-k) | |
625 | (vector-push! uses (var->idx var) use-k)) | |
626 | ||
627 | (define* (declare-block! label cont parent | |
628 | #:optional (level | |
629 | (1+ (vector-ref | |
630 | scope-levels | |
631 | (label->idx parent))))) | |
632 | (vector-set! conts (label->idx label) cont) | |
633 | (vector-set! scopes (label->idx label) parent) | |
634 | (vector-set! scope-levels (label->idx label) level)) | |
635 | ||
636 | (define (link-blocks! pred succ) | |
637 | (vector-push! preds (label->idx succ) pred)) | |
638 | ||
639 | (define (visit-cont cont label) | |
640 | (match cont | |
641 | (($ $kargs names syms body) | |
642 | (for-each (cut add-def! <> label) syms) | |
643 | (visit-term body label)) | |
a16af113 AW |
644 | (($ $kreceive arity k) |
645 | (link-blocks! label k)))) | |
646 | ||
647 | (define (visit-term term label) | |
648 | (match term | |
649 | (($ $letk (($ $cont k cont) ...) body) | |
650 | ;; Set up recursive environment before visiting cont bodies. | |
651 | (for-each/2 (lambda (cont k) | |
652 | (declare-block! k cont label)) | |
653 | cont k) | |
654 | (for-each/2 visit-cont cont k) | |
655 | (visit-term body label)) | |
656 | (($ $letrec names syms funs body) | |
657 | (unless global? | |
658 | (error "$letrec should not be present when building a local DFG")) | |
659 | (for-each (cut add-def! <> label) syms) | |
660 | (for-each (lambda (fun) | |
661 | (match fun | |
662 | (($ $fun free body) | |
663 | (visit-fun body)))) | |
664 | funs) | |
665 | (visit-term body label)) | |
666 | (($ $continue k src exp) | |
667 | (link-blocks! label k) | |
668 | (visit-exp exp label)))) | |
669 | ||
670 | (define (visit-exp exp label) | |
671 | (define (use! sym) | |
672 | (add-use! sym label)) | |
673 | (match exp | |
a9ec16f9 | 674 | ((or ($ $const) ($ $prim) ($ $closure)) #f) |
a16af113 AW |
675 | (($ $call proc args) |
676 | (use! proc) | |
677 | (for-each use! args)) | |
678 | (($ $callk k proc args) | |
679 | (use! proc) | |
680 | (for-each use! args)) | |
681 | (($ $primcall name args) | |
682 | (for-each use! args)) | |
92805e21 AW |
683 | (($ $branch kt exp) |
684 | (link-blocks! label kt) | |
685 | (visit-exp exp label)) | |
a16af113 AW |
686 | (($ $values args) |
687 | (for-each use! args)) | |
688 | (($ $prompt escape? tag handler) | |
689 | (use! tag) | |
690 | (link-blocks! label handler)) | |
691 | (($ $fun free body) | |
692 | (when global? | |
693 | (visit-fun body))))) | |
694 | ||
695 | (define (visit-clause clause kfun) | |
696 | (match clause | |
697 | (#f #t) | |
698 | (($ $cont kclause | |
699 | (and clause ($ $kclause arity ($ $cont kbody body) | |
700 | alternate))) | |
701 | (declare-block! kclause clause kfun) | |
702 | (link-blocks! kfun kclause) | |
703 | ||
704 | (declare-block! kbody body kclause) | |
705 | (link-blocks! kclause kbody) | |
706 | ||
707 | (visit-cont body kbody) | |
708 | (visit-clause alternate kfun)))) | |
709 | ||
710 | (define (visit-fun fun) | |
711 | (match fun | |
712 | (($ $cont kfun | |
713 | (and cont | |
714 | ($ $kfun src meta self ($ $cont ktail tail) clause))) | |
715 | (declare-block! kfun cont #f 0) | |
716 | (add-def! self kfun) | |
717 | (declare-block! ktail tail kfun) | |
718 | (visit-clause clause kfun)))) | |
719 | ||
720 | (visit-fun fun) | |
721 | ||
722 | (make-dfg conts preds defs uses scopes scope-levels | |
723 | min-label max-label label-count | |
724 | min-var max-var var-count))))) | |
3e1b97c1 | 725 | |
fb512cac AW |
726 | (define* (dump-dfg dfg #:optional (port (current-output-port))) |
727 | (let ((min-label (dfg-min-label dfg)) | |
728 | (min-var (dfg-min-var dfg))) | |
729 | (define (label->idx label) (- label min-label)) | |
730 | (define (idx->label idx) (+ idx min-label)) | |
731 | (define (var->idx var) (- var min-var)) | |
732 | (define (idx->var idx) (+ idx min-var)) | |
733 | ||
734 | (let lp ((label (dfg-min-label dfg))) | |
51177f35 | 735 | (when (<= label (dfg-max-label dfg)) |
fb512cac AW |
736 | (let ((cont (vector-ref (dfg-cont-table dfg) (label->idx label)))) |
737 | (when cont | |
738 | (unless (equal? (lookup-predecessors label dfg) (list (1- label))) | |
739 | (newline port)) | |
740 | (format port "k~a:~8t" label) | |
741 | (match cont | |
fb512cac AW |
742 | (($ $kreceive arity k) |
743 | (format port "$kreceive ~a k~a\n" arity k)) | |
744 | (($ $kfun src meta self tail clause) | |
745 | (format port "$kfun ~a ~a v~a\n" src meta self)) | |
746 | (($ $ktail) | |
747 | (format port "$ktail\n")) | |
748 | (($ $kclause arity ($ $cont kbody) alternate) | |
749 | (format port "$kclause ~a k~a" arity kbody) | |
750 | (match alternate | |
751 | (#f #f) | |
752 | (($ $cont kalt) (format port " -> k~a" kalt))) | |
753 | (newline port)) | |
754 | (($ $kargs names vars term) | |
755 | (unless (null? vars) | |
756 | (format port "v~a[~a]~:{ v~a[~a]~}: " | |
757 | (car vars) (car names) (map list (cdr vars) (cdr names)))) | |
758 | (match (find-call term) | |
92805e21 AW |
759 | (($ $continue kf src ($ $branch kt exp)) |
760 | (format port "if ") | |
761 | (match exp | |
762 | (($ $primcall name args) | |
763 | (format port "(~a~{ v~a~})" name args)) | |
764 | (($ $values (arg)) | |
765 | (format port "v~a" arg))) | |
766 | (format port " k~a k~a\n" kt kf)) | |
fb512cac AW |
767 | (($ $continue k src exp) |
768 | (match exp | |
fb512cac AW |
769 | (($ $const val) (format port "const ~@y" val)) |
770 | (($ $prim name) (format port "prim ~a" name)) | |
771 | (($ $fun free ($ $cont kbody)) (format port "fun k~a" kbody)) | |
772 | (($ $closure label nfree) (format port "closure k~a (~a free)" label nfree)) | |
773 | (($ $call proc args) (format port "call~{ v~a~}" (cons proc args))) | |
774 | (($ $callk k proc args) (format port "callk k~a~{ v~a~}" k (cons proc args))) | |
775 | (($ $primcall name args) (format port "~a~{ v~a~}" name args)) | |
776 | (($ $values args) (format port "values~{ v~a~}" args)) | |
777 | (($ $prompt escape? tag handler) (format port "prompt ~a v~a k~a" escape? tag handler))) | |
778 | (unless (= k (1+ label)) | |
779 | (format port " -> k~a" k)) | |
780 | (newline port)))))) | |
781 | (lp (1+ label))))))) | |
782 | ||
3e1b97c1 AW |
783 | (define-syntax-rule (with-fresh-name-state-from-dfg dfg body ...) |
784 | (parameterize ((label-counter (1+ (dfg-max-label dfg))) | |
785 | (var-counter (1+ (dfg-max-var dfg)))) | |
786 | body ...)) | |
5e897908 | 787 | |
f49e994b AW |
788 | (define (lookup-cont label dfg) |
789 | (let ((res (vector-ref (dfg-cont-table dfg) (- label (dfg-min-label dfg))))) | |
790 | (unless res | |
791 | (error "Unknown continuation!" label)) | |
792 | res)) | |
793 | ||
5fc40391 AW |
794 | (define (lookup-predecessors k dfg) |
795 | (vector-ref (dfg-preds dfg) (- k (dfg-min-label dfg)))) | |
796 | ||
797 | (define (lookup-successors k dfg) | |
2c3c086e AW |
798 | (let ((cont (vector-ref (dfg-cont-table dfg) (- k (dfg-min-label dfg))))) |
799 | (visit-cont-successors list cont))) | |
6e8ad823 | 800 | |
5e897908 | 801 | (define (lookup-def var dfg) |
f49e994b | 802 | (vector-ref (dfg-defs dfg) (- var (dfg-min-var dfg)))) |
6e8ad823 | 803 | |
5e897908 | 804 | (define (lookup-uses var dfg) |
f49e994b | 805 | (vector-ref (dfg-uses dfg) (- var (dfg-min-var dfg)))) |
6e8ad823 | 806 | |
c8ad7426 | 807 | (define (lookup-block-scope k dfg) |
5fc40391 | 808 | (vector-ref (dfg-scopes dfg) (- k (dfg-min-label dfg)))) |
f22979db | 809 | |
5fc40391 AW |
810 | (define (lookup-scope-level k dfg) |
811 | (vector-ref (dfg-scope-levels dfg) (- k (dfg-min-label dfg)))) | |
f22979db | 812 | |
6e8ad823 | 813 | (define (find-defining-term sym dfg) |
f22979db | 814 | (match (lookup-predecessors (lookup-def sym dfg) dfg) |
6e8ad823 | 815 | ((def-exp-k) |
fbdb69b2 | 816 | (lookup-cont def-exp-k dfg)) |
6e8ad823 AW |
817 | (else #f))) |
818 | ||
819 | (define (find-call term) | |
820 | (match term | |
821 | (($ $kargs names syms body) (find-call body)) | |
822 | (($ $letk conts body) (find-call body)) | |
823 | (($ $letrec names syms funs body) (find-call body)) | |
824 | (($ $continue) term))) | |
825 | ||
826 | (define (call-expression call) | |
827 | (match call | |
6e422a35 | 828 | (($ $continue k src exp) exp))) |
6e8ad823 AW |
829 | |
830 | (define (find-expression term) | |
831 | (call-expression (find-call term))) | |
832 | ||
833 | (define (find-defining-expression sym dfg) | |
834 | (match (find-defining-term sym dfg) | |
835 | (#f #f) | |
36527695 | 836 | (($ $kreceive) #f) |
f22979db | 837 | (($ $kclause) #f) |
6e8ad823 AW |
838 | (term (find-expression term)))) |
839 | ||
840 | (define (find-constant-value sym dfg) | |
841 | (match (find-defining-expression sym dfg) | |
842 | (($ $const val) | |
843 | (values #t val)) | |
6e8ad823 AW |
844 | (else |
845 | (values #f #f)))) | |
846 | ||
36aeda5b | 847 | (define (constant-needs-allocation? var val dfg) |
607fe5a6 AW |
848 | (define (immediate-u8? val) |
849 | (and (integer? val) (exact? val) (<= 0 val 255))) | |
850 | ||
6e8ad823 AW |
851 | (define (find-exp term) |
852 | (match term | |
36aeda5b | 853 | (($ $kargs names vars body) (find-exp body)) |
6e8ad823 AW |
854 | (($ $letk conts body) (find-exp body)) |
855 | (else term))) | |
f49e994b AW |
856 | |
857 | (or-map | |
858 | (lambda (use) | |
859 | (match (find-expression (lookup-cont use dfg)) | |
860 | (($ $call) #f) | |
861 | (($ $callk) #f) | |
862 | (($ $values) #f) | |
863 | (($ $primcall 'free-ref (closure slot)) | |
36aeda5b | 864 | (eq? var closure)) |
f49e994b | 865 | (($ $primcall 'free-set! (closure slot value)) |
36aeda5b | 866 | (or (eq? var closure) (eq? var value))) |
f49e994b | 867 | (($ $primcall 'cache-current-module! (mod . _)) |
36aeda5b | 868 | (eq? var mod)) |
f49e994b AW |
869 | (($ $primcall 'cached-toplevel-box _) |
870 | #f) | |
871 | (($ $primcall 'cached-module-box _) | |
872 | #f) | |
873 | (($ $primcall 'resolve (name bound?)) | |
36aeda5b | 874 | (eq? var name)) |
f49e994b | 875 | (($ $primcall 'make-vector/immediate (len init)) |
36aeda5b | 876 | (eq? var init)) |
f49e994b | 877 | (($ $primcall 'vector-ref/immediate (v i)) |
36aeda5b | 878 | (eq? var v)) |
f49e994b | 879 | (($ $primcall 'vector-set!/immediate (v i x)) |
36aeda5b | 880 | (or (eq? var v) (eq? var x))) |
f49e994b | 881 | (($ $primcall 'allocate-struct/immediate (vtable nfields)) |
36aeda5b | 882 | (eq? var vtable)) |
f49e994b | 883 | (($ $primcall 'struct-ref/immediate (s n)) |
36aeda5b | 884 | (eq? var s)) |
f49e994b | 885 | (($ $primcall 'struct-set!/immediate (s n x)) |
36aeda5b | 886 | (or (eq? var s) (eq? var x))) |
f49e994b AW |
887 | (($ $primcall 'builtin-ref (idx)) |
888 | #f) | |
889 | (_ #t))) | |
36aeda5b | 890 | (vector-ref (dfg-uses dfg) (- var (dfg-min-var dfg))))) |
6e8ad823 | 891 | |
5e897908 AW |
892 | (define (continuation-scope-contains? scope-k k dfg) |
893 | (let ((scope-level (lookup-scope-level scope-k dfg))) | |
f22979db AW |
894 | (let lp ((k k)) |
895 | (or (eq? scope-k k) | |
5fc40391 AW |
896 | (and (< scope-level (lookup-scope-level k dfg)) |
897 | (lp (lookup-block-scope k dfg))))))) | |
f22979db | 898 | |
f22979db | 899 | (define (continuation-bound-in? k use-k dfg) |
21d6d183 | 900 | (continuation-scope-contains? (lookup-block-scope k dfg) use-k dfg)) |
d51fb1e6 AW |
901 | |
902 | (define (variable-free-in? var k dfg) | |
5e897908 AW |
903 | (or-map (lambda (use) |
904 | (continuation-scope-contains? k use dfg)) | |
905 | (lookup-uses var dfg))) | |
6e8ad823 | 906 | |
e636f424 | 907 | ;; A continuation is a control point if it has multiple predecessors, or |
a3a45279 | 908 | ;; if its single predecessor does not have a single successor. |
e636f424 AW |
909 | (define (control-point? k dfg) |
910 | (match (lookup-predecessors k dfg) | |
911 | ((pred) | |
2c3c086e AW |
912 | (let ((cont (vector-ref (dfg-cont-table dfg) |
913 | (- pred (dfg-min-label dfg))))) | |
914 | (visit-cont-successors (case-lambda | |
915 | (() #t) | |
916 | ((succ0) #f) | |
917 | ((succ1 succ2) #t)) | |
918 | cont))) | |
e636f424 | 919 | (_ #t))) |
6e8ad823 AW |
920 | |
921 | (define (lookup-bound-syms k dfg) | |
fbdb69b2 AW |
922 | (match (lookup-cont k dfg) |
923 | (($ $kargs names syms body) | |
924 | syms))) |