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6e8ad823 AW |
1 | ;;; Continuation-passing style (CPS) intermediate language (IL) |
2 | ||
6eb02960 | 3 | ;; Copyright (C) 2013, 2014 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) | |
39 | #:use-module (srfi srfi-1) | |
40 | #:use-module (srfi srfi-9) | |
41 | #:use-module (srfi srfi-26) | |
42 | #:use-module (language cps) | |
43 | #:export (build-cont-table | |
44 | build-local-cont-table | |
45 | lookup-cont | |
46 | ||
47 | compute-dfg | |
48 | dfg-cont-table | |
49 | lookup-def | |
50 | lookup-uses | |
f22979db AW |
51 | lookup-predecessors |
52 | lookup-successors | |
c8ad7426 | 53 | lookup-block-scope |
6e8ad823 AW |
54 | find-call |
55 | call-expression | |
56 | find-expression | |
57 | find-defining-expression | |
58 | find-constant-value | |
f22979db | 59 | continuation-bound-in? |
d51fb1e6 | 60 | variable-free-in? |
6e8ad823 | 61 | constant-needs-allocation? |
e636f424 | 62 | control-point? |
db11440d AW |
63 | lookup-bound-syms |
64 | ||
dda5fd94 AW |
65 | ;; Control flow analysis. |
66 | analyze-control-flow | |
67 | cfa-k-idx cfa-k-count cfa-k-sym cfa-predecessors | |
68 | ||
db11440d AW |
69 | ;; Data flow analysis. |
70 | compute-live-variables | |
71 | dfa-k-idx dfa-k-sym dfa-k-count dfa-k-in dfa-k-out | |
72 | dfa-var-idx dfa-var-name dfa-var-sym dfa-var-count | |
73 | print-dfa)) | |
6e8ad823 AW |
74 | |
75 | (define (build-cont-table fun) | |
6e422a35 | 76 | (fold-conts (lambda (k cont table) |
6e8ad823 AW |
77 | (hashq-set! table k cont) |
78 | table) | |
79 | (make-hash-table) | |
80 | fun)) | |
81 | ||
82 | (define (build-local-cont-table cont) | |
6e422a35 | 83 | (fold-local-conts (lambda (k cont table) |
6e8ad823 AW |
84 | (hashq-set! table k cont) |
85 | table) | |
86 | (make-hash-table) | |
87 | cont)) | |
88 | ||
89 | (define (lookup-cont sym conts) | |
90 | (let ((res (hashq-ref conts sym))) | |
91 | (unless res | |
92 | (error "Unknown continuation!" sym (hash-fold acons '() conts))) | |
93 | res)) | |
94 | ||
95 | ;; Data-flow graph for CPS: both for values and continuations. | |
96 | (define-record-type $dfg | |
f22979db | 97 | (make-dfg conts blocks use-maps) |
6e8ad823 | 98 | dfg? |
f22979db | 99 | ;; hash table of sym -> $kif, $kargs, etc |
6e8ad823 | 100 | (conts dfg-cont-table) |
f22979db AW |
101 | ;; hash table of sym -> $block |
102 | (blocks dfg-blocks) | |
6e8ad823 | 103 | ;; hash table of sym -> $use-map |
f22979db | 104 | (use-maps dfg-use-maps)) |
6e8ad823 AW |
105 | |
106 | (define-record-type $use-map | |
fc95a944 | 107 | (make-use-map name sym def uses) |
6e8ad823 | 108 | use-map? |
fc95a944 | 109 | (name use-map-name) |
6e8ad823 AW |
110 | (sym use-map-sym) |
111 | (def use-map-def) | |
112 | (uses use-map-uses set-use-map-uses!)) | |
113 | ||
f22979db | 114 | (define-record-type $block |
334bd8e3 | 115 | (%make-block scope scope-level preds succs) |
f22979db AW |
116 | block? |
117 | (scope block-scope set-block-scope!) | |
118 | (scope-level block-scope-level set-block-scope-level!) | |
119 | (preds block-preds set-block-preds!) | |
334bd8e3 | 120 | (succs block-succs set-block-succs!)) |
f22979db AW |
121 | |
122 | (define (make-block scope scope-level) | |
334bd8e3 | 123 | (%make-block scope scope-level '() '())) |
f22979db | 124 | |
5bff3125 AW |
125 | ;; Some analyses assume that the only relevant set of nodes is the set |
126 | ;; that is reachable from some start node. Others need to include nodes | |
127 | ;; that are reachable from an end node as well, or all nodes in a | |
128 | ;; function. In that case pass an appropriate implementation of | |
6eb02960 AW |
129 | ;; fold-all-conts, as analyze-control-flow does. |
130 | (define (reverse-post-order k0 get-successors fold-all-conts) | |
3aee6cfd AW |
131 | (let ((order '()) |
132 | (visited? (make-hash-table))) | |
133 | (let visit ((k k0)) | |
134 | (hashq-set! visited? k #t) | |
0e2446d4 AW |
135 | (for-each (lambda (k) |
136 | (unless (hashq-ref visited? k) | |
137 | (visit k))) | |
334bd8e3 | 138 | (get-successors k)) |
0e2446d4 | 139 | (set! order (cons k order))) |
5bff3125 AW |
140 | (list->vector (fold-all-conts |
141 | (lambda (k seed) | |
142 | (if (hashq-ref visited? k) | |
143 | seed | |
144 | (begin | |
145 | (hashq-set! visited? k #t) | |
146 | (cons k seed)))) | |
147 | order)))) | |
3aee6cfd | 148 | |
334bd8e3 AW |
149 | (define (make-block-mapping order) |
150 | (let ((mapping (make-hash-table))) | |
366eb4d7 AW |
151 | (let lp ((n 0)) |
152 | (when (< n (vector-length order)) | |
153 | (hashq-set! mapping (vector-ref order n) n) | |
154 | (lp (1+ n)))) | |
334bd8e3 AW |
155 | mapping)) |
156 | ||
157 | (define (convert-predecessors order get-predecessors) | |
158 | (let ((preds-vec (make-vector (vector-length order) #f))) | |
366eb4d7 AW |
159 | (let lp ((n 0)) |
160 | (when (< n (vector-length order)) | |
334bd8e3 AW |
161 | (vector-set! preds-vec n (get-predecessors (vector-ref order n))) |
162 | (lp (1+ n)))) | |
3aee6cfd AW |
163 | preds-vec)) |
164 | ||
334bd8e3 AW |
165 | ;; Control-flow analysis. |
166 | (define-record-type $cfa | |
dda5fd94 | 167 | (make-cfa k-map order preds) |
334bd8e3 AW |
168 | cfa? |
169 | ;; Hash table mapping k-sym -> k-idx | |
170 | (k-map cfa-k-map) | |
171 | ;; Vector of k-idx -> k-sym, in reverse post order | |
172 | (order cfa-order) | |
173 | ;; Vector of k-idx -> list of k-idx | |
dda5fd94 AW |
174 | (preds cfa-preds)) |
175 | ||
176 | (define* (cfa-k-idx cfa k | |
177 | #:key (default (lambda (k) | |
178 | (error "unknown k" k)))) | |
179 | (or (hashq-ref (cfa-k-map cfa) k) | |
180 | (default k))) | |
181 | ||
182 | (define (cfa-k-count cfa) | |
183 | (vector-length (cfa-order cfa))) | |
184 | ||
185 | (define (cfa-k-sym cfa n) | |
186 | (vector-ref (cfa-order cfa) n)) | |
187 | ||
188 | (define (cfa-predecessors cfa n) | |
189 | (vector-ref (cfa-preds cfa) n)) | |
190 | ||
9002277d AW |
191 | (define-inlinable (vector-push! vec idx val) |
192 | (let ((v vec) (i idx)) | |
193 | (vector-set! v i (cons val (vector-ref v i))))) | |
194 | ||
195 | (define (compute-reachable cfa dfg) | |
196 | "Given the forward control-flow analysis in CFA, compute and return | |
197 | the continuations that may be reached if flow reaches a continuation N. | |
198 | Returns a vector of bitvectors. The given CFA should be a forward CFA, | |
199 | for quickest convergence." | |
200 | (let* ((k-count (cfa-k-count cfa)) | |
201 | ;; Vector of bitvectors, indicating that continuation N can | |
202 | ;; reach a set M... | |
203 | (reachable (make-vector k-count #f)) | |
204 | ;; Vector of lists, indicating that continuation N can directly | |
205 | ;; reach continuations M... | |
206 | (succs (make-vector k-count '()))) | |
207 | ||
208 | ;; All continuations are reachable from themselves. | |
209 | (let lp ((n 0)) | |
210 | (when (< n k-count) | |
211 | (let ((bv (make-bitvector k-count #f))) | |
212 | (bitvector-set! bv n #t) | |
213 | (vector-set! reachable n bv) | |
214 | (lp (1+ n))))) | |
215 | ||
216 | ;; Initialize successor lists. | |
217 | (let lp ((n 0)) | |
218 | (when (< n k-count) | |
219 | (for-each (lambda (succ) | |
220 | (vector-push! succs n (cfa-k-idx cfa succ))) | |
221 | (block-succs (lookup-block (cfa-k-sym cfa n) | |
222 | (dfg-blocks dfg)))) | |
223 | (lp (1+ n)))) | |
224 | ||
225 | ;; Iterate cfa backwards, to converge quickly. | |
226 | (let ((tmp (make-bitvector k-count #f))) | |
227 | (let lp ((n k-count) (changed? #f)) | |
228 | (cond | |
229 | ((zero? n) | |
230 | (if changed? | |
231 | (lp 0 #f) | |
232 | reachable)) | |
233 | (else | |
234 | (let ((n (1- n))) | |
235 | (bitvector-fill! tmp #f) | |
236 | (for-each (lambda (succ) | |
237 | (bit-set*! tmp (vector-ref reachable succ) #t)) | |
238 | (vector-ref succs n)) | |
239 | (bitvector-set! tmp n #t) | |
240 | (bit-set*! tmp (vector-ref reachable n) #f) | |
241 | (cond | |
242 | ((bit-position #t tmp 0) | |
243 | (bit-set*! (vector-ref reachable n) tmp #t) | |
244 | (lp n #t)) | |
245 | (else | |
246 | (lp n changed?)))))))))) | |
247 | ||
248 | (define (find-prompts cfa dfg) | |
249 | "Find the prompts in CFA, and return them as a list of PROMPT-INDEX, | |
250 | HANDLER-INDEX pairs." | |
251 | (let lp ((n 0) (prompts '())) | |
252 | (cond | |
253 | ((= n (cfa-k-count cfa)) | |
254 | (reverse prompts)) | |
255 | (else | |
256 | (match (lookup-cont (cfa-k-sym cfa n) (dfg-cont-table dfg)) | |
257 | (($ $kargs names syms body) | |
258 | (match (find-expression body) | |
259 | (($ $prompt escape? tag handler) | |
260 | (lp (1+ n) (acons n (cfa-k-idx cfa handler) prompts))) | |
261 | (_ (lp (1+ n) prompts)))) | |
262 | (_ (lp (1+ n) prompts))))))) | |
263 | ||
264 | (define (compute-interval cfa dfg reachable start end) | |
265 | "Compute and return the set of continuations that may be reached from | |
266 | START, inclusive, but not reached by END, exclusive. Returns a | |
267 | bitvector." | |
268 | (let ((body (make-bitvector (cfa-k-count cfa) #f))) | |
269 | (bit-set*! body (vector-ref reachable start) #t) | |
270 | (bit-set*! body (vector-ref reachable end) #f) | |
271 | body)) | |
272 | ||
273 | (define (find-prompt-bodies cfa dfg) | |
274 | "Find all the prompts in CFA, and compute the set of continuations | |
275 | that is reachable from the prompt bodies but not from the corresponding | |
276 | handler. Returns a list of PROMPT, HANDLER, BODY lists, where the BODY | |
277 | is a bitvector." | |
278 | (match (find-prompts cfa dfg) | |
279 | (() '()) | |
280 | (((prompt . handler) ...) | |
281 | (let ((reachable (compute-reachable cfa dfg))) | |
282 | (map (lambda (prompt handler) | |
283 | ;; FIXME: It isn't correct to use all continuations | |
284 | ;; reachable from the prompt, because that includes | |
285 | ;; continuations outside the prompt body. This point is | |
286 | ;; moot if the handler's control flow joins with the the | |
287 | ;; body, as is usually but not always the case. | |
288 | ;; | |
289 | ;; One counter-example is when the handler contifies an | |
290 | ;; infinite loop; in that case we compute a too-large | |
291 | ;; prompt body. This error is currently innocuous, but | |
292 | ;; we should fix it at some point. | |
293 | ;; | |
294 | ;; The fix is to end the body at the corresponding "pop" | |
295 | ;; primcall, if any. | |
296 | (let ((body (compute-interval cfa dfg reachable prompt handler))) | |
297 | (list prompt handler body))) | |
298 | prompt handler))))) | |
299 | ||
300 | (define* (visit-prompt-control-flow cfa dfg f #:key complete?) | |
301 | "For all prompts in CFA, invoke F with arguments PROMPT, HANDLER, and | |
302 | BODY for each body continuation in the prompt." | |
303 | (for-each | |
304 | (match-lambda | |
305 | ((prompt handler body) | |
306 | (define (out-or-back-edge? n) | |
307 | ;; Most uses of visit-prompt-control-flow don't need every body | |
308 | ;; continuation, and would be happy getting called only for | |
309 | ;; continuations that postdominate the rest of the body. Unless | |
310 | ;; you pass #:complete? #t, we only invoke F on continuations | |
311 | ;; that can leave the body, or on back-edges in loops. | |
312 | ;; | |
313 | ;; You would think that looking for the final "pop" primcall | |
314 | ;; would be sufficient, but that is incorrect; it's possible for | |
315 | ;; a loop in the prompt body to be contified, and that loop need | |
316 | ;; not continue to the pop if it never terminates. The pop could | |
317 | ;; even be removed by DCE, in that case. | |
318 | (or-map (lambda (succ) | |
319 | (let ((succ (cfa-k-idx cfa succ))) | |
320 | (or (not (bitvector-ref body succ)) | |
321 | (<= succ n)))) | |
322 | (block-succs (lookup-block (cfa-k-sym cfa n) | |
323 | (dfg-blocks dfg))))) | |
324 | (let lp ((n 0)) | |
325 | (let ((n (bit-position #t body n))) | |
326 | (when n | |
327 | (when (or complete? (out-or-back-edge? n)) | |
328 | (f prompt handler n)) | |
329 | (lp (1+ n))))))) | |
330 | (find-prompt-bodies cfa dfg))) | |
331 | ||
332 | (define* (analyze-control-flow fun dfg #:key reverse? add-handler-preds?) | |
333 | (define (build-cfa kentry block-succs block-preds forward-cfa) | |
dda5fd94 AW |
334 | (define (block-accessor accessor) |
335 | (lambda (k) | |
336 | (accessor (lookup-block k (dfg-blocks dfg))))) | |
337 | (define (reachable-preds mapping accessor) | |
338 | ;; It's possible for a predecessor to not be in the mapping, if | |
339 | ;; the predecessor is not reachable from the entry node. | |
340 | (lambda (k) | |
341 | (filter-map (cut hashq-ref mapping <>) | |
342 | ((block-accessor accessor) k)))) | |
9002277d AW |
343 | (let* ((order (reverse-post-order |
344 | kentry | |
345 | (block-accessor block-succs) | |
346 | (if forward-cfa | |
347 | (lambda (f seed) | |
348 | (let lp ((n (cfa-k-count forward-cfa)) (seed seed)) | |
349 | (if (zero? n) | |
350 | seed | |
351 | (lp (1- n) | |
352 | (f (cfa-k-sym forward-cfa (1- n)) seed))))) | |
353 | (lambda (f seed) seed)))) | |
dda5fd94 AW |
354 | (k-map (make-block-mapping order)) |
355 | (preds (convert-predecessors order | |
9002277d AW |
356 | (reachable-preds k-map block-preds))) |
357 | (cfa (make-cfa k-map order preds))) | |
358 | (when add-handler-preds? | |
359 | ;; Any expression in the prompt body could cause an abort to the | |
360 | ;; handler. This code adds links from every block in the prompt | |
361 | ;; body to the handler. This causes all values used by the | |
362 | ;; handler to be seen as live in the prompt body, as indeed they | |
363 | ;; are. | |
364 | (let ((forward-cfa (or forward-cfa cfa))) | |
365 | (visit-prompt-control-flow | |
366 | forward-cfa dfg | |
367 | (lambda (prompt handler body) | |
368 | (define (renumber n) | |
369 | (if (eq? forward-cfa cfa) | |
370 | n | |
371 | (cfa-k-idx cfa (cfa-k-sym forward-cfa n)))) | |
372 | (let ((handler (renumber handler)) | |
373 | (body (renumber body))) | |
374 | (if reverse? | |
375 | (vector-push! preds body handler) | |
376 | (vector-push! preds handler body))))))) | |
377 | cfa)) | |
dda5fd94 | 378 | (match fun |
6e422a35 AW |
379 | (($ $fun src meta free |
380 | ($ $cont kentry | |
dda5fd94 | 381 | (and entry |
6e422a35 | 382 | ($ $kentry self ($ $cont ktail tail) clauses)))) |
dda5fd94 | 383 | (if reverse? |
6eb02960 | 384 | (build-cfa ktail block-preds block-succs |
9002277d AW |
385 | (analyze-control-flow fun dfg #:reverse? #f |
386 | #:add-handler-preds? #f)) | |
387 | (build-cfa kentry block-succs block-preds #f))))) | |
dda5fd94 AW |
388 | |
389 | ;; Dominator analysis. | |
390 | (define-record-type $dominator-analysis | |
391 | (make-dominator-analysis cfa idoms dom-levels loop-header irreducible) | |
392 | dominator-analysis? | |
393 | ;; The corresponding $cfa | |
394 | (cfa dominator-analysis-cfa) | |
334bd8e3 | 395 | ;; Vector of k-idx -> k-idx |
dda5fd94 | 396 | (idoms dominator-analysis-idoms) |
334bd8e3 | 397 | ;; Vector of k-idx -> dom-level |
dda5fd94 | 398 | (dom-levels dominator-analysis-dom-levels) |
334bd8e3 | 399 | ;; Vector of k-idx -> k-idx or -1 |
dda5fd94 | 400 | (loop-header dominator-analysis-loop-header) |
334bd8e3 | 401 | ;; Vector of k-idx -> true or false value |
dda5fd94 | 402 | (irreducible dominator-analysis-irreducible)) |
334bd8e3 | 403 | |
366eb4d7 AW |
404 | (define (compute-dom-levels idoms) |
405 | (let ((dom-levels (make-vector (vector-length idoms) #f))) | |
3aee6cfd AW |
406 | (define (compute-dom-level n) |
407 | (or (vector-ref dom-levels n) | |
408 | (let ((dom-level (1+ (compute-dom-level (vector-ref idoms n))))) | |
409 | (vector-set! dom-levels n dom-level) | |
410 | dom-level))) | |
411 | (vector-set! dom-levels 0 0) | |
412 | (let lp ((n 0)) | |
366eb4d7 AW |
413 | (when (< n (vector-length idoms)) |
414 | (compute-dom-level n) | |
415 | (lp (1+ n)))) | |
416 | dom-levels)) | |
3aee6cfd | 417 | |
366eb4d7 AW |
418 | (define (compute-idoms preds) |
419 | (let ((idoms (make-vector (vector-length preds) 0))) | |
3aee6cfd AW |
420 | (define (common-idom d0 d1) |
421 | ;; We exploit the fact that a reverse post-order is a topological | |
422 | ;; sort, and so the idom of a node is always numerically less than | |
423 | ;; the node itself. | |
424 | (cond | |
425 | ((= d0 d1) d0) | |
426 | ((< d0 d1) (common-idom d0 (vector-ref idoms d1))) | |
427 | (else (common-idom (vector-ref idoms d0) d1)))) | |
428 | (define (compute-idom preds) | |
429 | (match preds | |
430 | (() 0) | |
431 | ((pred . preds) | |
432 | (let lp ((idom pred) (preds preds)) | |
433 | (match preds | |
434 | (() idom) | |
435 | ((pred . preds) | |
436 | (lp (common-idom idom pred) preds))))))) | |
437 | ;; This is the iterative O(n^2) fixpoint algorithm, originally from | |
438 | ;; Allen and Cocke ("Graph-theoretic constructs for program flow | |
439 | ;; analysis", 1972). See the discussion in Cooper, Harvey, and | |
440 | ;; Kennedy's "A Simple, Fast Dominance Algorithm", 2001. | |
441 | (let iterate ((n 0) (changed? #f)) | |
442 | (cond | |
443 | ((< n (vector-length preds)) | |
444 | (let ((idom (vector-ref idoms n)) | |
445 | (idom* (compute-idom (vector-ref preds n)))) | |
446 | (cond | |
447 | ((eqv? idom idom*) | |
448 | (iterate (1+ n) changed?)) | |
449 | (else | |
450 | (vector-set! idoms n idom*) | |
451 | (iterate (1+ n) #t))))) | |
452 | (changed? | |
453 | (iterate 0 #f)) | |
366eb4d7 AW |
454 | (else idoms))))) |
455 | ||
96b8027c AW |
456 | ;; Compute a vector containing, for each node, a list of the nodes that |
457 | ;; it immediately dominates. These are the "D" edges in the DJ tree. | |
458 | (define (compute-dom-edges idoms) | |
459 | (let ((doms (make-vector (vector-length idoms) '()))) | |
460 | (let lp ((n 0)) | |
461 | (when (< n (vector-length idoms)) | |
462 | (let ((idom (vector-ref idoms n))) | |
463 | (vector-push! doms idom n)) | |
464 | (lp (1+ n)))) | |
465 | doms)) | |
466 | ||
467 | ;; Compute a vector containing, for each node, a list of the successors | |
468 | ;; of that node that are not dominated by that node. These are the "J" | |
469 | ;; edges in the DJ tree. | |
470 | (define (compute-join-edges preds idoms) | |
471 | (define (dominates? n1 n2) | |
472 | (or (= n1 n2) | |
473 | (and (< n1 n2) | |
474 | (dominates? n1 (vector-ref idoms n2))))) | |
475 | (let ((joins (make-vector (vector-length idoms) '()))) | |
476 | (let lp ((n 0)) | |
477 | (when (< n (vector-length preds)) | |
478 | (for-each (lambda (pred) | |
479 | (unless (dominates? pred n) | |
480 | (vector-push! joins pred n))) | |
481 | (vector-ref preds n)) | |
482 | (lp (1+ n)))) | |
483 | joins)) | |
484 | ||
485 | ;; Compute a vector containing, for each node, a list of the back edges | |
486 | ;; to that node. If a node is not the entry of a reducible loop, that | |
487 | ;; list is empty. | |
488 | (define (compute-reducible-back-edges joins idoms) | |
489 | (define (dominates? n1 n2) | |
490 | (or (= n1 n2) | |
491 | (and (< n1 n2) | |
492 | (dominates? n1 (vector-ref idoms n2))))) | |
493 | (let ((back-edges (make-vector (vector-length idoms) '()))) | |
494 | (let lp ((n 0)) | |
495 | (when (< n (vector-length joins)) | |
496 | (for-each (lambda (succ) | |
497 | (when (dominates? succ n) | |
498 | (vector-push! back-edges succ n))) | |
499 | (vector-ref joins n)) | |
500 | (lp (1+ n)))) | |
501 | back-edges)) | |
502 | ||
503 | ;; Compute the levels in the dominator tree at which there are | |
504 | ;; irreducible loops, as an integer. If a bit N is set in the integer, | |
505 | ;; that indicates that at level N in the dominator tree, there is at | |
506 | ;; least one irreducible loop. | |
507 | (define (compute-irreducible-dom-levels doms joins idoms dom-levels) | |
366eb4d7 AW |
508 | (define (dominates? n1 n2) |
509 | (or (= n1 n2) | |
510 | (and (< n1 n2) | |
511 | (dominates? n1 (vector-ref idoms n2))))) | |
96b8027c AW |
512 | (let ((pre-order (make-vector (vector-length doms) #f)) |
513 | (last-pre-order (make-vector (vector-length doms) #f)) | |
514 | (res 0) | |
515 | (count 0)) | |
516 | ;; Is MAYBE-PARENT an ancestor of N on the depth-first spanning tree | |
517 | ;; computed from the DJ graph? See Havlak 1997, "Nesting of | |
518 | ;; Reducible and Irreducible Loops". | |
519 | (define (ancestor? a b) | |
520 | (let ((w (vector-ref pre-order a)) | |
521 | (v (vector-ref pre-order b))) | |
522 | (and (<= w v) | |
523 | (<= v (vector-ref last-pre-order w))))) | |
524 | ;; Compute depth-first spanning tree of DJ graph. | |
525 | (define (recurse n) | |
526 | (unless (vector-ref pre-order n) | |
527 | (visit n))) | |
528 | (define (visit n) | |
529 | ;; Pre-order visitation index. | |
530 | (vector-set! pre-order n count) | |
531 | (set! count (1+ count)) | |
532 | (for-each recurse (vector-ref doms n)) | |
533 | (for-each recurse (vector-ref joins n)) | |
534 | ;; Pre-order visitation index of last descendant. | |
535 | (vector-set! last-pre-order (vector-ref pre-order n) (1- count))) | |
536 | ||
537 | (visit 0) | |
538 | ||
539 | (let lp ((n 0)) | |
540 | (when (< n (vector-length joins)) | |
541 | (for-each (lambda (succ) | |
542 | ;; If this join edge is not a loop back edge but it | |
543 | ;; does go to an ancestor on the DFST of the DJ | |
544 | ;; graph, then we have an irreducible loop. | |
545 | (when (and (not (dominates? succ n)) | |
546 | (ancestor? succ n)) | |
547 | (set! res (logior (ash 1 (vector-ref dom-levels succ)))))) | |
548 | (vector-ref joins n)) | |
549 | (lp (1+ n)))) | |
550 | ||
551 | res)) | |
552 | ||
553 | (define (compute-nodes-by-level dom-levels) | |
554 | (let* ((max-level (let lp ((n 0) (max-level 0)) | |
555 | (if (< n (vector-length dom-levels)) | |
556 | (lp (1+ n) (max (vector-ref dom-levels n) max-level)) | |
557 | max-level))) | |
558 | (nodes-by-level (make-vector (1+ max-level) '()))) | |
559 | (let lp ((n (1- (vector-length dom-levels)))) | |
560 | (when (>= n 0) | |
561 | (vector-push! nodes-by-level (vector-ref dom-levels n) n) | |
562 | (lp (1- n)))) | |
563 | nodes-by-level)) | |
564 | ||
565 | ;; Collect all predecessors to the back-nodes that are strictly | |
566 | ;; dominated by the loop header, and mark them as belonging to the loop. | |
567 | ;; If they already have a loop header, that means they are either in a | |
568 | ;; nested loop, or they have already been visited already. | |
569 | (define (mark-loop-body header back-nodes preds idoms loop-headers) | |
570 | (define (strictly-dominates? n1 n2) | |
571 | (and (< n1 n2) | |
572 | (let ((idom (vector-ref idoms n2))) | |
573 | (or (= n1 idom) | |
574 | (strictly-dominates? n1 idom))))) | |
575 | (define (visit node) | |
576 | (when (strictly-dominates? header node) | |
577 | (cond | |
578 | ((vector-ref loop-headers node) => visit) | |
579 | (else | |
580 | (vector-set! loop-headers node header) | |
581 | (for-each visit (vector-ref preds node)))))) | |
582 | (for-each visit back-nodes)) | |
583 | ||
584 | (define (mark-irreducible-loops level idoms dom-levels loop-headers) | |
585 | ;; FIXME: Identify strongly-connected components that are >= LEVEL in | |
586 | ;; the dominator tree, and somehow mark them as irreducible. | |
587 | (warn 'irreducible-loops-at-level level)) | |
588 | ||
589 | ;; "Identifying Loops Using DJ Graphs" by Sreedhar, Gao, and Lee, ACAPS | |
590 | ;; Technical Memo 98, 1995. | |
591 | (define (identify-loops preds idoms dom-levels) | |
592 | (let* ((doms (compute-dom-edges idoms)) | |
593 | (joins (compute-join-edges preds idoms)) | |
594 | (back-edges (compute-reducible-back-edges joins idoms)) | |
595 | (irreducible-levels | |
596 | (compute-irreducible-dom-levels doms joins idoms dom-levels)) | |
597 | (loop-headers (make-vector (vector-length preds) #f)) | |
598 | (nodes-by-level (compute-nodes-by-level dom-levels))) | |
599 | (let lp ((level (1- (vector-length nodes-by-level)))) | |
600 | (when (>= level 0) | |
601 | (for-each (lambda (n) | |
602 | (let ((edges (vector-ref back-edges n))) | |
603 | (unless (null? edges) | |
604 | (mark-loop-body n edges preds idoms loop-headers)))) | |
605 | (vector-ref nodes-by-level level)) | |
606 | (when (logbit? level irreducible-levels) | |
607 | (mark-irreducible-loops level idoms dom-levels loop-headers)) | |
608 | (lp (1- level)))) | |
609 | loop-headers)) | |
366eb4d7 | 610 | |
dda5fd94 AW |
611 | (define (analyze-dominators cfa) |
612 | (match cfa | |
613 | (($ $cfa k-map order preds) | |
614 | (let* ((idoms (compute-idoms preds)) | |
615 | (dom-levels (compute-dom-levels idoms)) | |
616 | (loop-headers (identify-loops preds idoms dom-levels))) | |
617 | (make-dominator-analysis cfa idoms dom-levels loop-headers #f))))) | |
3aee6cfd | 618 | |
db11440d AW |
619 | |
620 | ;; Compute the maximum fixed point of the data-flow constraint problem. | |
621 | ;; | |
622 | ;; This always completes, as the graph is finite and the in and out sets | |
623 | ;; are complete semi-lattices. If the graph is reducible and the blocks | |
624 | ;; are sorted in reverse post-order, this completes in a maximum of LC + | |
625 | ;; 2 iterations, where LC is the loop connectedness number. See Hecht | |
626 | ;; and Ullman, "Analysis of a simple algorithm for global flow | |
627 | ;; problems", POPL 1973, or the recent summary in "Notes on graph | |
628 | ;; algorithms used in optimizing compilers", Offner 2013. | |
629 | (define (compute-maximum-fixed-point preds inv outv killv genv union?) | |
630 | (define (bitvector-copy! dst src) | |
631 | (bitvector-fill! dst #f) | |
632 | (bit-set*! dst src #t)) | |
633 | (define (bitvector-meet! accum src) | |
634 | (bit-set*! accum src union?)) | |
635 | (let lp ((n 0) (changed? #f)) | |
636 | (cond | |
637 | ((< n (vector-length preds)) | |
638 | (let ((in (vector-ref inv n)) | |
639 | (out (vector-ref outv n)) | |
640 | (kill (vector-ref killv n)) | |
641 | (gen (vector-ref genv n))) | |
642 | (let ((out-count (or changed? (bit-count #t out)))) | |
643 | (for-each | |
644 | (lambda (pred) | |
645 | (bitvector-meet! in (vector-ref outv pred))) | |
646 | (vector-ref preds n)) | |
647 | (bitvector-copy! out in) | |
648 | (for-each (cut bitvector-set! out <> #f) kill) | |
649 | (for-each (cut bitvector-set! out <> #t) gen) | |
650 | (lp (1+ n) | |
651 | (or changed? (not (eqv? out-count (bit-count #t out)))))))) | |
652 | (changed? | |
653 | (lp 0 #f))))) | |
654 | ||
655 | ;; Data-flow analysis. | |
656 | (define-record-type $dfa | |
f235f926 | 657 | (make-dfa cfa var-map names syms in out) |
db11440d | 658 | dfa? |
f235f926 AW |
659 | ;; CFA, for its reverse-post-order numbering |
660 | (cfa dfa-cfa) | |
334bd8e3 AW |
661 | ;; Hash table mapping var-sym -> var-idx |
662 | (var-map dfa-var-map) | |
db11440d AW |
663 | ;; Vector of var-idx -> name |
664 | (names dfa-names) | |
665 | ;; Vector of var-idx -> var-sym | |
666 | (syms dfa-syms) | |
667 | ;; Vector of k-idx -> bitvector | |
668 | (in dfa-in) | |
669 | ;; Vector of k-idx -> bitvector | |
670 | (out dfa-out)) | |
671 | ||
672 | (define (dfa-k-idx dfa k) | |
f235f926 | 673 | (cfa-k-idx (dfa-cfa dfa) k)) |
db11440d AW |
674 | |
675 | (define (dfa-k-sym dfa idx) | |
f235f926 | 676 | (cfa-k-sym (dfa-cfa dfa) idx)) |
db11440d AW |
677 | |
678 | (define (dfa-k-count dfa) | |
f235f926 | 679 | (cfa-k-count (dfa-cfa dfa))) |
db11440d AW |
680 | |
681 | (define (dfa-var-idx dfa var) | |
334bd8e3 AW |
682 | (or (hashq-ref (dfa-var-map dfa) var) |
683 | (error "unknown var" var))) | |
db11440d AW |
684 | |
685 | (define (dfa-var-name dfa idx) | |
686 | (vector-ref (dfa-names dfa) idx)) | |
687 | ||
688 | (define (dfa-var-sym dfa idx) | |
689 | (vector-ref (dfa-syms dfa) idx)) | |
690 | ||
691 | (define (dfa-var-count dfa) | |
692 | (vector-length (dfa-syms dfa))) | |
693 | ||
694 | (define (dfa-k-in dfa idx) | |
695 | (vector-ref (dfa-in dfa) idx)) | |
696 | ||
697 | (define (dfa-k-out dfa idx) | |
698 | (vector-ref (dfa-out dfa) idx)) | |
699 | ||
5bff3125 | 700 | (define (compute-live-variables fun dfg) |
334bd8e3 | 701 | (define (make-variable-mapping use-maps) |
db11440d AW |
702 | (let ((mapping (make-hash-table)) |
703 | (n 0)) | |
704 | (hash-for-each (lambda (sym use-map) | |
705 | (hashq-set! mapping sym n) | |
706 | (set! n (1+ n))) | |
707 | use-maps) | |
334bd8e3 | 708 | (values mapping n))) |
f235f926 AW |
709 | (call-with-values (lambda () (make-variable-mapping (dfg-use-maps dfg))) |
710 | (lambda (var-map nvars) | |
146ce52d AW |
711 | (let* ((cfa (analyze-control-flow fun dfg #:reverse? #t |
712 | #:add-handler-preds? #t)) | |
f235f926 AW |
713 | (syms (make-vector nvars #f)) |
714 | (names (make-vector nvars #f)) | |
715 | (usev (make-vector (cfa-k-count cfa) '())) | |
716 | (defv (make-vector (cfa-k-count cfa) '())) | |
717 | (live-in (make-vector (cfa-k-count cfa) #f)) | |
718 | (live-out (make-vector (cfa-k-count cfa) #f))) | |
719 | ;; Initialize syms, names, defv, and usev. | |
720 | (hash-for-each | |
721 | (lambda (sym use-map) | |
722 | (match use-map | |
723 | (($ $use-map name sym def uses) | |
724 | (let ((v (or (hashq-ref var-map sym) | |
725 | (error "unknown var" sym)))) | |
726 | (vector-set! syms v sym) | |
727 | (vector-set! names v name) | |
728 | (for-each (lambda (def) | |
729 | (vector-push! defv (cfa-k-idx cfa def) v)) | |
730 | (block-preds (lookup-block def (dfg-blocks dfg)))) | |
731 | (for-each (lambda (use) | |
732 | (vector-push! usev (cfa-k-idx cfa use) v)) | |
733 | uses))))) | |
734 | (dfg-use-maps dfg)) | |
735 | ||
736 | ;; Initialize live-in and live-out sets. | |
737 | (let lp ((n 0)) | |
738 | (when (< n (vector-length live-out)) | |
739 | (vector-set! live-in n (make-bitvector nvars #f)) | |
740 | (vector-set! live-out n (make-bitvector nvars #f)) | |
741 | (lp (1+ n)))) | |
742 | ||
743 | ;; Liveness is a reverse data-flow problem, so we give | |
744 | ;; compute-maximum-fixed-point a reversed graph, swapping in | |
745 | ;; for out, and usev for defv. Note that since we are using | |
746 | ;; a reverse CFA, cfa-preds are actually successors, and | |
747 | ;; continuation 0 is ktail. | |
748 | (compute-maximum-fixed-point (cfa-preds cfa) | |
749 | live-out live-in defv usev #t) | |
750 | ||
751 | (make-dfa cfa var-map names syms live-in live-out))))) | |
db11440d AW |
752 | |
753 | (define (print-dfa dfa) | |
754 | (match dfa | |
f235f926 | 755 | (($ $dfa cfa var-map names syms in out) |
db11440d AW |
756 | (define (print-var-set bv) |
757 | (let lp ((n 0)) | |
758 | (let ((n (bit-position #t bv n))) | |
759 | (when n | |
760 | (format #t " ~A" (vector-ref syms n)) | |
761 | (lp (1+ n)))))) | |
762 | (let lp ((n 0)) | |
f235f926 AW |
763 | (when (< n (cfa-k-count cfa)) |
764 | (format #t "~A:\n" (cfa-k-sym cfa n)) | |
db11440d AW |
765 | (format #t " in:") |
766 | (print-var-set (vector-ref in n)) | |
767 | (newline) | |
768 | (format #t " out:") | |
769 | (print-var-set (vector-ref out n)) | |
770 | (newline) | |
771 | (lp (1+ n))))))) | |
772 | ||
f22979db | 773 | (define (visit-fun fun conts blocks use-maps global?) |
fc95a944 | 774 | (define (add-def! name sym def-k) |
6e8ad823 AW |
775 | (unless def-k |
776 | (error "Term outside labelled continuation?")) | |
fc95a944 | 777 | (hashq-set! use-maps sym (make-use-map name sym def-k '()))) |
6e8ad823 AW |
778 | |
779 | (define (add-use! sym use-k) | |
780 | (match (hashq-ref use-maps sym) | |
781 | (#f (error "Symbol out of scope?" sym)) | |
fc95a944 | 782 | ((and use-map ($ $use-map name sym def uses)) |
6e8ad823 AW |
783 | (set-use-map-uses! use-map (cons use-k uses))))) |
784 | ||
f22979db AW |
785 | (define* (declare-block! label cont parent |
786 | #:optional (level | |
787 | (1+ (lookup-scope-level parent blocks)))) | |
788 | (hashq-set! conts label cont) | |
789 | (hashq-set! blocks label (make-block parent level))) | |
790 | ||
791 | (define (link-blocks! pred succ) | |
792 | (let ((pred-block (hashq-ref blocks pred)) | |
793 | (succ-block (hashq-ref blocks succ))) | |
794 | (unless (and pred-block succ-block) | |
c8ad7426 | 795 | (error "internal error" pred-block succ-block)) |
f22979db AW |
796 | (set-block-succs! pred-block (cons succ (block-succs pred-block))) |
797 | (set-block-preds! succ-block (cons pred (block-preds succ-block))))) | |
6e8ad823 AW |
798 | |
799 | (define (visit exp exp-k) | |
fc95a944 AW |
800 | (define (def! name sym) |
801 | (add-def! name sym exp-k)) | |
6e8ad823 AW |
802 | (define (use! sym) |
803 | (add-use! sym exp-k)) | |
3aee6cfd AW |
804 | (define (use-k! k) |
805 | (link-blocks! exp-k k)) | |
6e8ad823 AW |
806 | (define (recur exp) |
807 | (visit exp exp-k)) | |
808 | (match exp | |
6e422a35 | 809 | (($ $letk (($ $cont k cont) ...) body) |
6e8ad823 AW |
810 | ;; Set up recursive environment before visiting cont bodies. |
811 | (for-each (lambda (cont k) | |
f22979db | 812 | (declare-block! k cont exp-k)) |
6e8ad823 AW |
813 | cont k) |
814 | (for-each visit cont k) | |
815 | (recur body)) | |
816 | ||
817 | (($ $kargs names syms body) | |
fc95a944 | 818 | (for-each def! names syms) |
6e8ad823 AW |
819 | (recur body)) |
820 | ||
821 | (($ $kif kt kf) | |
f22979db AW |
822 | (use-k! kt) |
823 | (use-k! kf)) | |
6e8ad823 | 824 | |
36527695 | 825 | (($ $kreceive arity k) |
f22979db | 826 | (use-k! k)) |
6e8ad823 AW |
827 | |
828 | (($ $letrec names syms funs body) | |
829 | (unless global? | |
830 | (error "$letrec should not be present when building a local DFG")) | |
fc95a944 | 831 | (for-each def! names syms) |
f22979db | 832 | (for-each (cut visit-fun <> conts blocks use-maps global?) funs) |
6e8ad823 AW |
833 | (visit body exp-k)) |
834 | ||
6e422a35 | 835 | (($ $continue k src exp) |
f22979db | 836 | (use-k! k) |
6e8ad823 | 837 | (match exp |
6e8ad823 AW |
838 | (($ $call proc args) |
839 | (use! proc) | |
840 | (for-each use! args)) | |
841 | ||
842 | (($ $primcall name args) | |
843 | (for-each use! args)) | |
844 | ||
845 | (($ $values args) | |
846 | (for-each use! args)) | |
847 | ||
7ab76a83 | 848 | (($ $prompt escape? tag handler) |
6e8ad823 | 849 | (use! tag) |
146ce52d | 850 | (use-k! handler)) |
6e8ad823 AW |
851 | |
852 | (($ $fun) | |
853 | (when global? | |
f22979db | 854 | (visit-fun exp conts blocks use-maps global?))) |
6e8ad823 AW |
855 | |
856 | (_ #f))))) | |
857 | ||
858 | (match fun | |
6e422a35 AW |
859 | (($ $fun src meta free |
860 | ($ $cont kentry | |
6e8ad823 | 861 | (and entry |
6e422a35 | 862 | ($ $kentry self ($ $cont ktail tail) clauses)))) |
f22979db | 863 | (declare-block! kentry entry #f 0) |
fc95a944 | 864 | (add-def! #f self kentry) |
6e8ad823 | 865 | |
f22979db | 866 | (declare-block! ktail tail kentry) |
6e8ad823 AW |
867 | |
868 | (for-each | |
869 | (match-lambda | |
6e422a35 AW |
870 | (($ $cont kclause |
871 | (and clause ($ $kclause arity ($ $cont kbody body)))) | |
f22979db AW |
872 | (declare-block! kclause clause kentry) |
873 | (link-blocks! kentry kclause) | |
6e8ad823 | 874 | |
f22979db AW |
875 | (declare-block! kbody body kclause) |
876 | (link-blocks! kclause kbody) | |
6e8ad823 AW |
877 | |
878 | (visit body kbody))) | |
dda5fd94 | 879 | clauses)))) |
6e8ad823 AW |
880 | |
881 | (define* (compute-dfg fun #:key (global? #t)) | |
882 | (let* ((conts (make-hash-table)) | |
f22979db AW |
883 | (blocks (make-hash-table)) |
884 | (use-maps (make-hash-table))) | |
885 | (visit-fun fun conts blocks use-maps global?) | |
886 | (make-dfg conts blocks use-maps))) | |
6e8ad823 | 887 | |
f22979db AW |
888 | (define (lookup-block k blocks) |
889 | (let ((res (hashq-ref blocks k))) | |
6e8ad823 | 890 | (unless res |
f22979db | 891 | (error "Unknown continuation!" k (hash-fold acons '() blocks))) |
6e8ad823 AW |
892 | res)) |
893 | ||
f22979db AW |
894 | (define (lookup-scope-level k blocks) |
895 | (match (lookup-block k blocks) | |
896 | (($ $block _ scope-level) scope-level))) | |
897 | ||
6e8ad823 AW |
898 | (define (lookup-use-map sym use-maps) |
899 | (let ((res (hashq-ref use-maps sym))) | |
900 | (unless res | |
901 | (error "Unknown lexical!" sym (hash-fold acons '() use-maps))) | |
902 | res)) | |
903 | ||
904 | (define (lookup-def sym dfg) | |
905 | (match dfg | |
f22979db | 906 | (($ $dfg conts blocks use-maps) |
6e8ad823 | 907 | (match (lookup-use-map sym use-maps) |
fc95a944 | 908 | (($ $use-map name sym def uses) |
6e8ad823 AW |
909 | def))))) |
910 | ||
911 | (define (lookup-uses sym dfg) | |
912 | (match dfg | |
f22979db | 913 | (($ $dfg conts blocks use-maps) |
6e8ad823 | 914 | (match (lookup-use-map sym use-maps) |
fc95a944 | 915 | (($ $use-map name sym def uses) |
6e8ad823 AW |
916 | uses))))) |
917 | ||
c8ad7426 AW |
918 | (define (lookup-block-scope k dfg) |
919 | (block-scope (lookup-block k (dfg-blocks dfg)))) | |
920 | ||
f22979db AW |
921 | (define (lookup-predecessors k dfg) |
922 | (match (lookup-block k (dfg-blocks dfg)) | |
923 | (($ $block _ _ preds succs) preds))) | |
924 | ||
925 | (define (lookup-successors k dfg) | |
926 | (match (lookup-block k (dfg-blocks dfg)) | |
927 | (($ $block _ _ preds succs) succs))) | |
928 | ||
6e8ad823 | 929 | (define (find-defining-term sym dfg) |
f22979db | 930 | (match (lookup-predecessors (lookup-def sym dfg) dfg) |
6e8ad823 AW |
931 | ((def-exp-k) |
932 | (lookup-cont def-exp-k (dfg-cont-table dfg))) | |
933 | (else #f))) | |
934 | ||
935 | (define (find-call term) | |
936 | (match term | |
937 | (($ $kargs names syms body) (find-call body)) | |
938 | (($ $letk conts body) (find-call body)) | |
939 | (($ $letrec names syms funs body) (find-call body)) | |
940 | (($ $continue) term))) | |
941 | ||
942 | (define (call-expression call) | |
943 | (match call | |
6e422a35 | 944 | (($ $continue k src exp) exp))) |
6e8ad823 AW |
945 | |
946 | (define (find-expression term) | |
947 | (call-expression (find-call term))) | |
948 | ||
949 | (define (find-defining-expression sym dfg) | |
950 | (match (find-defining-term sym dfg) | |
951 | (#f #f) | |
36527695 | 952 | (($ $kreceive) #f) |
f22979db | 953 | (($ $kclause) #f) |
6e8ad823 AW |
954 | (term (find-expression term)))) |
955 | ||
956 | (define (find-constant-value sym dfg) | |
957 | (match (find-defining-expression sym dfg) | |
958 | (($ $const val) | |
959 | (values #t val)) | |
6e422a35 | 960 | (($ $continue k src ($ $void)) |
6e8ad823 AW |
961 | (values #t *unspecified*)) |
962 | (else | |
963 | (values #f #f)))) | |
964 | ||
965 | (define (constant-needs-allocation? sym val dfg) | |
607fe5a6 AW |
966 | (define (immediate-u8? val) |
967 | (and (integer? val) (exact? val) (<= 0 val 255))) | |
968 | ||
6e8ad823 AW |
969 | (define (find-exp term) |
970 | (match term | |
971 | (($ $kargs names syms body) (find-exp body)) | |
972 | (($ $letk conts body) (find-exp body)) | |
973 | (else term))) | |
974 | (match dfg | |
f22979db | 975 | (($ $dfg conts blocks use-maps) |
6e8ad823 | 976 | (match (lookup-use-map sym use-maps) |
fc95a944 | 977 | (($ $use-map _ _ def uses) |
6e8ad823 AW |
978 | (or-map |
979 | (lambda (use) | |
980 | (match (find-expression (lookup-cont use conts)) | |
981 | (($ $call) #f) | |
58ef5f07 | 982 | (($ $values) #f) |
6e8ad823 AW |
983 | (($ $primcall 'free-ref (closure slot)) |
984 | (not (eq? sym slot))) | |
985 | (($ $primcall 'free-set! (closure slot value)) | |
986 | (not (eq? sym slot))) | |
987 | (($ $primcall 'cache-current-module! (mod . _)) | |
988 | (eq? sym mod)) | |
989 | (($ $primcall 'cached-toplevel-box _) | |
990 | #f) | |
991 | (($ $primcall 'cached-module-box _) | |
992 | #f) | |
993 | (($ $primcall 'resolve (name bound?)) | |
994 | (eq? sym name)) | |
4c906ad5 AW |
995 | (($ $primcall 'make-vector/immediate (len init)) |
996 | (not (eq? sym len))) | |
997 | (($ $primcall 'vector-ref/immediate (v i)) | |
998 | (not (eq? sym i))) | |
999 | (($ $primcall 'vector-set!/immediate (v i x)) | |
1000 | (not (eq? sym i))) | |
1001 | (($ $primcall 'allocate-struct/immediate (vtable nfields)) | |
1002 | (not (eq? sym nfields))) | |
1003 | (($ $primcall 'struct-ref/immediate (s n)) | |
1004 | (not (eq? sym n))) | |
1005 | (($ $primcall 'struct-set!/immediate (s n x)) | |
1006 | (not (eq? sym n))) | |
486013d6 AW |
1007 | (($ $primcall 'builtin-ref (idx)) |
1008 | #f) | |
6e8ad823 AW |
1009 | (_ #t))) |
1010 | uses)))))) | |
1011 | ||
f22979db AW |
1012 | (define (continuation-scope-contains? scope-k k blocks) |
1013 | (let ((scope-level (lookup-scope-level scope-k blocks))) | |
1014 | (let lp ((k k)) | |
1015 | (or (eq? scope-k k) | |
1016 | (match (lookup-block k blocks) | |
1017 | (($ $block scope level) | |
1018 | (and (< scope-level level) | |
1019 | (lp scope)))))))) | |
1020 | ||
f22979db | 1021 | (define (continuation-bound-in? k use-k dfg) |
d51fb1e6 | 1022 | (match dfg |
f22979db AW |
1023 | (($ $dfg conts blocks use-maps) |
1024 | (match (lookup-block k blocks) | |
1025 | (($ $block def-k) | |
1026 | (continuation-scope-contains? def-k use-k blocks)))))) | |
d51fb1e6 AW |
1027 | |
1028 | (define (variable-free-in? var k dfg) | |
6e8ad823 | 1029 | (match dfg |
f22979db | 1030 | (($ $dfg conts blocks use-maps) |
6e8ad823 | 1031 | (or-map (lambda (use) |
f22979db | 1032 | (continuation-scope-contains? k use blocks)) |
6e8ad823 | 1033 | (match (lookup-use-map var use-maps) |
fc95a944 | 1034 | (($ $use-map name sym def uses) |
6e8ad823 AW |
1035 | uses)))))) |
1036 | ||
e636f424 AW |
1037 | ;; A continuation is a control point if it has multiple predecessors, or |
1038 | ;; if its single predecessor has multiple successors. | |
1039 | (define (control-point? k dfg) | |
1040 | (match (lookup-predecessors k dfg) | |
1041 | ((pred) | |
1042 | (match (lookup-successors pred dfg) | |
1043 | ((_) #f) | |
1044 | (_ #t))) | |
1045 | (_ #t))) | |
6e8ad823 AW |
1046 | |
1047 | (define (lookup-bound-syms k dfg) | |
1048 | (match dfg | |
f22979db | 1049 | (($ $dfg conts blocks use-maps) |
6e8ad823 AW |
1050 | (match (lookup-cont k conts) |
1051 | (($ $kargs names syms body) | |
1052 | syms))))) |