Commit | Line | Data |
---|---|---|
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) | |
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) | |
44 | #:export (build-cont-table | |
6e8ad823 AW |
45 | lookup-cont |
46 | ||
47 | compute-dfg | |
48 | dfg-cont-table | |
a8430ab1 AW |
49 | dfg-min-label |
50 | dfg-label-count | |
51 | dfg-min-var | |
52 | dfg-var-count | |
3e1b97c1 | 53 | with-fresh-name-state-from-dfg |
6e8ad823 AW |
54 | lookup-def |
55 | lookup-uses | |
f22979db AW |
56 | lookup-predecessors |
57 | lookup-successors | |
c8ad7426 | 58 | lookup-block-scope |
6e8ad823 AW |
59 | find-call |
60 | call-expression | |
61 | find-expression | |
62 | find-defining-expression | |
63 | find-constant-value | |
f22979db | 64 | continuation-bound-in? |
d51fb1e6 | 65 | variable-free-in? |
6e8ad823 | 66 | constant-needs-allocation? |
e636f424 | 67 | control-point? |
db11440d AW |
68 | lookup-bound-syms |
69 | ||
70 | ;; Data flow analysis. | |
71 | compute-live-variables | |
72 | dfa-k-idx dfa-k-sym dfa-k-count dfa-k-in dfa-k-out | |
29619661 | 73 | dfa-var-idx dfa-var-sym dfa-var-count |
db11440d | 74 | print-dfa)) |
6e8ad823 | 75 | |
48c2a539 AW |
76 | ;; These definitions are here because currently we don't do cross-module |
77 | ;; inlining. They can be removed once that restriction is gone. | |
78 | (define-inlinable (for-each f l) | |
79 | (unless (list? l) | |
80 | (scm-error 'wrong-type-arg "for-each" "Not a list: ~S" (list l) #f)) | |
81 | (let for-each1 ((l l)) | |
82 | (unless (null? l) | |
83 | (f (car l)) | |
84 | (for-each1 (cdr l))))) | |
85 | ||
86 | (define-inlinable (for-each/2 f l1 l2) | |
87 | (unless (= (length l1) (length l2)) | |
88 | (scm-error 'wrong-type-arg "for-each" "List of wrong length: ~S" | |
89 | (list l2) #f)) | |
90 | (let for-each2 ((l1 l1) (l2 l2)) | |
91 | (unless (null? l1) | |
92 | (f (car l1) (car l2)) | |
93 | (for-each2 (cdr l1) (cdr l2))))) | |
94 | ||
6e8ad823 | 95 | (define (build-cont-table fun) |
fbdb69b2 AW |
96 | (let ((max-k (fold-conts (lambda (k cont max-k) (max k max-k)) |
97 | -1 fun))) | |
98 | (fold-conts (lambda (k cont table) | |
99 | (vector-set! table k cont) | |
100 | table) | |
101 | (make-vector (1+ max-k) #f) | |
102 | fun))) | |
103 | ||
6e8ad823 AW |
104 | ;; Data-flow graph for CPS: both for values and continuations. |
105 | (define-record-type $dfg | |
4bf757b8 | 106 | (make-dfg conts preds defs uses scopes scope-levels |
3e1b97c1 AW |
107 | min-label max-label label-count |
108 | min-var max-var var-count) | |
6e8ad823 | 109 | dfg? |
5e897908 | 110 | ;; vector of label -> $kif, $kargs, etc |
6e8ad823 | 111 | (conts dfg-cont-table) |
5fc40391 | 112 | ;; vector of label -> (pred-label ...) |
21d6d183 | 113 | (preds dfg-preds) |
5fc40391 | 114 | ;; vector of var -> def-label |
98c5b69f | 115 | (defs dfg-defs) |
5fc40391 | 116 | ;; vector of var -> (use-label ...) |
98c5b69f | 117 | (uses dfg-uses) |
5fc40391 AW |
118 | ;; vector of label -> label |
119 | (scopes dfg-scopes) | |
120 | ;; vector of label -> int | |
121 | (scope-levels dfg-scope-levels) | |
5e897908 AW |
122 | |
123 | (min-label dfg-min-label) | |
3e1b97c1 | 124 | (max-label dfg-max-label) |
a8430ab1 | 125 | (label-count dfg-label-count) |
3e1b97c1 | 126 | |
5e897908 | 127 | (min-var dfg-min-var) |
3e1b97c1 | 128 | (max-var dfg-max-var) |
a8430ab1 | 129 | (var-count dfg-var-count)) |
6e8ad823 | 130 | |
9002277d AW |
131 | (define-inlinable (vector-push! vec idx val) |
132 | (let ((v vec) (i idx)) | |
133 | (vector-set! v i (cons val (vector-ref v i))))) | |
134 | ||
16af91e8 | 135 | (define (compute-reachable dfg min-label label-count) |
4ec3ded0 AW |
136 | "Compute and return the continuations that may be reached if flow |
137 | reaches a continuation N. Returns a vector of bitvectors, whose first | |
138 | index corresponds to MIN-LABEL, and so on." | |
16af91e8 AW |
139 | (let (;; Vector of bitvectors, indicating that continuation N can |
140 | ;; reach a set M... | |
141 | (reachable (make-vector label-count #f))) | |
142 | ||
143 | (define (label->idx label) (- label min-label)) | |
9002277d AW |
144 | |
145 | ;; All continuations are reachable from themselves. | |
146 | (let lp ((n 0)) | |
16af91e8 AW |
147 | (when (< n label-count) |
148 | (let ((bv (make-bitvector label-count #f))) | |
9002277d AW |
149 | (bitvector-set! bv n #t) |
150 | (vector-set! reachable n bv) | |
151 | (lp (1+ n))))) | |
152 | ||
4ec3ded0 | 153 | ;; Iterate labels backwards, to converge quickly. |
16af91e8 AW |
154 | (let ((tmp (make-bitvector label-count #f))) |
155 | (define (add-reachable! succ) | |
156 | (bit-set*! tmp (vector-ref reachable (label->idx succ)) #t)) | |
157 | (let lp ((label (+ min-label label-count)) (changed? #f)) | |
9002277d | 158 | (cond |
16af91e8 | 159 | ((= label min-label) |
9002277d | 160 | (if changed? |
16af91e8 | 161 | (lp (+ min-label label-count) #f) |
9002277d AW |
162 | reachable)) |
163 | (else | |
16af91e8 AW |
164 | (let* ((label (1- label)) |
165 | (idx (label->idx label))) | |
9002277d | 166 | (bitvector-fill! tmp #f) |
16af91e8 AW |
167 | (visit-cont-successors |
168 | (case-lambda | |
169 | (() #t) | |
170 | ((succ0) (add-reachable! succ0)) | |
171 | ((succ0 succ1) (add-reachable! succ0) (add-reachable! succ1))) | |
172 | (lookup-cont label dfg)) | |
173 | (bitvector-set! tmp idx #t) | |
174 | (bit-set*! tmp (vector-ref reachable idx) #f) | |
9002277d AW |
175 | (cond |
176 | ((bit-position #t tmp 0) | |
16af91e8 AW |
177 | (bit-set*! (vector-ref reachable idx) tmp #t) |
178 | (lp label #t)) | |
9002277d | 179 | (else |
16af91e8 | 180 | (lp label changed?)))))))))) |
9002277d | 181 | |
16af91e8 AW |
182 | (define (find-prompts dfg min-label label-count) |
183 | "Find the prompts in DFG between MIN-LABEL and MIN-LABEL + | |
184 | LABEL-COUNT, and return them as a list of PROMPT-LABEL, HANDLER-LABEL | |
185 | pairs." | |
186 | (let lp ((label min-label) (prompts '())) | |
9002277d | 187 | (cond |
16af91e8 | 188 | ((= label (+ min-label label-count)) |
9002277d AW |
189 | (reverse prompts)) |
190 | (else | |
16af91e8 | 191 | (match (lookup-cont label dfg) |
9002277d AW |
192 | (($ $kargs names syms body) |
193 | (match (find-expression body) | |
194 | (($ $prompt escape? tag handler) | |
16af91e8 AW |
195 | (lp (1+ label) (acons label handler prompts))) |
196 | (_ (lp (1+ label) prompts)))) | |
197 | (_ (lp (1+ label) prompts))))))) | |
9002277d | 198 | |
16af91e8 | 199 | (define (compute-interval reachable min-label label-count start end) |
9002277d AW |
200 | "Compute and return the set of continuations that may be reached from |
201 | START, inclusive, but not reached by END, exclusive. Returns a | |
202 | bitvector." | |
16af91e8 AW |
203 | (let ((body (make-bitvector label-count #f))) |
204 | (bit-set*! body (vector-ref reachable (- start min-label)) #t) | |
205 | (bit-set*! body (vector-ref reachable (- end min-label)) #f) | |
9002277d AW |
206 | body)) |
207 | ||
16af91e8 AW |
208 | (define (find-prompt-bodies dfg min-label label-count) |
209 | "Find all the prompts in DFG from the LABEL-COUNT continuations | |
210 | starting at MIN-LABEL, and compute the set of continuations that is | |
211 | reachable from the prompt bodies but not from the corresponding handler. | |
212 | Returns a list of PROMPT, HANDLER, BODY lists, where the BODY is a | |
213 | bitvector." | |
214 | (match (find-prompts dfg min-label label-count) | |
9002277d AW |
215 | (() '()) |
216 | (((prompt . handler) ...) | |
16af91e8 | 217 | (let ((reachable (compute-reachable dfg min-label label-count))) |
9002277d AW |
218 | (map (lambda (prompt handler) |
219 | ;; FIXME: It isn't correct to use all continuations | |
220 | ;; reachable from the prompt, because that includes | |
221 | ;; continuations outside the prompt body. This point is | |
222 | ;; moot if the handler's control flow joins with the the | |
223 | ;; body, as is usually but not always the case. | |
224 | ;; | |
225 | ;; One counter-example is when the handler contifies an | |
226 | ;; infinite loop; in that case we compute a too-large | |
16af91e8 AW |
227 | ;; prompt body. This error is currently innocuous, but we |
228 | ;; should fix it at some point. | |
9002277d AW |
229 | ;; |
230 | ;; The fix is to end the body at the corresponding "pop" | |
231 | ;; primcall, if any. | |
16af91e8 AW |
232 | (let ((body (compute-interval reachable min-label label-count |
233 | prompt handler))) | |
9002277d AW |
234 | (list prompt handler body))) |
235 | prompt handler))))) | |
236 | ||
16af91e8 | 237 | (define* (visit-prompt-control-flow dfg min-label label-count f #:key complete?) |
4ec3ded0 AW |
238 | "For all prompts in DFG in the range [MIN-LABEL, MIN-LABEL + |
239 | LABEL-COUNT), invoke F with arguments PROMPT, HANDLER, and BODY for each | |
240 | body continuation in the prompt." | |
16af91e8 AW |
241 | (define (label->idx label) (- label min-label)) |
242 | (define (idx->label idx) (+ idx min-label)) | |
9002277d AW |
243 | (for-each |
244 | (match-lambda | |
245 | ((prompt handler body) | |
246 | (define (out-or-back-edge? n) | |
247 | ;; Most uses of visit-prompt-control-flow don't need every body | |
248 | ;; continuation, and would be happy getting called only for | |
249 | ;; continuations that postdominate the rest of the body. Unless | |
250 | ;; you pass #:complete? #t, we only invoke F on continuations | |
251 | ;; that can leave the body, or on back-edges in loops. | |
252 | ;; | |
253 | ;; You would think that looking for the final "pop" primcall | |
254 | ;; would be sufficient, but that is incorrect; it's possible for | |
255 | ;; a loop in the prompt body to be contified, and that loop need | |
256 | ;; not continue to the pop if it never terminates. The pop could | |
257 | ;; even be removed by DCE, in that case. | |
258 | (or-map (lambda (succ) | |
16af91e8 | 259 | (let ((succ (label->idx succ))) |
9002277d AW |
260 | (or (not (bitvector-ref body succ)) |
261 | (<= succ n)))) | |
16af91e8 | 262 | (lookup-successors (idx->label n) dfg))) |
9002277d AW |
263 | (let lp ((n 0)) |
264 | (let ((n (bit-position #t body n))) | |
265 | (when n | |
266 | (when (or complete? (out-or-back-edge? n)) | |
16af91e8 | 267 | (f prompt handler (idx->label n))) |
9002277d | 268 | (lp (1+ n))))))) |
16af91e8 AW |
269 | (find-prompt-bodies dfg min-label label-count))) |
270 | ||
a7324faf AW |
271 | (define (analyze-reverse-control-flow fun dfg min-label label-count) |
272 | (define (compute-reverse-control-flow-order ktail dfg) | |
21a528fd | 273 | (let ((label-map (make-vector label-count #f)) |
16af91e8 AW |
274 | (next -1)) |
275 | (define (label->idx label) (- label min-label)) | |
276 | (define (idx->label idx) (+ idx min-label)) | |
277 | ||
278 | (let visit ((k ktail)) | |
279 | ;; Mark this label as visited. | |
280 | (vector-set! label-map (label->idx k) #t) | |
281 | (for-each (lambda (k) | |
282 | ;; Visit predecessors unless they are already visited. | |
283 | (unless (vector-ref label-map (label->idx k)) | |
284 | (visit k))) | |
285 | (lookup-predecessors k dfg)) | |
286 | ;; Add to reverse post-order chain. | |
287 | (vector-set! label-map (label->idx k) next) | |
288 | (set! next k)) | |
289 | ||
290 | (let lp ((n 0) (head next)) | |
291 | (if (< head 0) | |
292 | ;; Add nodes that are not reachable from the tail. | |
293 | (let lp ((n n) (m label-count)) | |
294 | (unless (= n label-count) | |
295 | (let find-unvisited ((m (1- m))) | |
296 | (if (vector-ref label-map m) | |
297 | (find-unvisited (1- m)) | |
298 | (begin | |
299 | (vector-set! label-map m n) | |
300 | (lp (1+ n) m)))))) | |
301 | ;; Pop the head off the chain, give it its | |
302 | ;; reverse-post-order numbering, and continue. | |
303 | (let ((next (vector-ref label-map (label->idx head)))) | |
304 | (vector-set! label-map (label->idx head) n) | |
305 | (lp (1+ n) next)))) | |
306 | ||
21a528fd | 307 | label-map)) |
16af91e8 | 308 | |
a7324faf | 309 | (define (convert-successors k-map) |
16af91e8 AW |
310 | (define (idx->label idx) (+ idx min-label)) |
311 | (define (renumber label) | |
312 | (vector-ref k-map (- label min-label))) | |
313 | (let ((succs (make-vector (vector-length k-map) #f))) | |
314 | (let lp ((n 0)) | |
315 | (when (< n (vector-length succs)) | |
316 | (vector-set! succs (vector-ref k-map n) | |
317 | (map renumber | |
318 | (lookup-successors (idx->label n) dfg))) | |
319 | (lp (1+ n)))) | |
320 | succs)) | |
321 | ||
a7324faf | 322 | (match fun |
6bc36ca5 | 323 | (($ $cont kfun ($ $kfun src meta self ($ $cont ktail tail))) |
21a528fd AW |
324 | (let* ((k-map (compute-reverse-control-flow-order ktail dfg)) |
325 | (succs (convert-successors k-map))) | |
326 | ;; Any expression in the prompt body could cause an abort to | |
327 | ;; the handler. This code adds links from every block in the | |
328 | ;; prompt body to the handler. This causes all values used | |
329 | ;; by the handler to be seen as live in the prompt body, as | |
330 | ;; indeed they are. | |
331 | (visit-prompt-control-flow | |
332 | dfg min-label label-count | |
333 | (lambda (prompt handler body) | |
334 | (define (renumber label) | |
335 | (vector-ref k-map (- label min-label))) | |
336 | (vector-push! succs (renumber body) (renumber handler)))) | |
337 | ||
338 | (values k-map succs))))) | |
dda5fd94 AW |
339 | |
340 | ;; Dominator analysis. | |
341 | (define-record-type $dominator-analysis | |
4ec3ded0 | 342 | (make-dominator-analysis min-label idoms dom-levels loop-header irreducible) |
dda5fd94 | 343 | dominator-analysis? |
4ec3ded0 AW |
344 | ;; Label corresponding to first entry in idoms, dom-levels, etc |
345 | (min-label dominator-analysis-min-label) | |
334bd8e3 | 346 | ;; Vector of k-idx -> k-idx |
dda5fd94 | 347 | (idoms dominator-analysis-idoms) |
334bd8e3 | 348 | ;; Vector of k-idx -> dom-level |
dda5fd94 | 349 | (dom-levels dominator-analysis-dom-levels) |
334bd8e3 | 350 | ;; Vector of k-idx -> k-idx or -1 |
dda5fd94 | 351 | (loop-header dominator-analysis-loop-header) |
334bd8e3 | 352 | ;; Vector of k-idx -> true or false value |
dda5fd94 | 353 | (irreducible dominator-analysis-irreducible)) |
334bd8e3 | 354 | |
366eb4d7 AW |
355 | (define (compute-dom-levels idoms) |
356 | (let ((dom-levels (make-vector (vector-length idoms) #f))) | |
3aee6cfd AW |
357 | (define (compute-dom-level n) |
358 | (or (vector-ref dom-levels n) | |
359 | (let ((dom-level (1+ (compute-dom-level (vector-ref idoms n))))) | |
360 | (vector-set! dom-levels n dom-level) | |
361 | dom-level))) | |
362 | (vector-set! dom-levels 0 0) | |
363 | (let lp ((n 0)) | |
366eb4d7 AW |
364 | (when (< n (vector-length idoms)) |
365 | (compute-dom-level n) | |
366 | (lp (1+ n)))) | |
367 | dom-levels)) | |
3aee6cfd | 368 | |
4ec3ded0 AW |
369 | (define (compute-idoms preds min-label label-count) |
370 | (define (label->idx label) (- label min-label)) | |
371 | (define (idx->label idx) (+ idx min-label)) | |
372 | (let ((idoms (make-vector label-count 0))) | |
3aee6cfd AW |
373 | (define (common-idom d0 d1) |
374 | ;; We exploit the fact that a reverse post-order is a topological | |
375 | ;; sort, and so the idom of a node is always numerically less than | |
376 | ;; the node itself. | |
377 | (cond | |
378 | ((= d0 d1) d0) | |
379 | ((< d0 d1) (common-idom d0 (vector-ref idoms d1))) | |
380 | (else (common-idom (vector-ref idoms d0) d1)))) | |
381 | (define (compute-idom preds) | |
382 | (match preds | |
383 | (() 0) | |
384 | ((pred . preds) | |
4ec3ded0 | 385 | (let lp ((idom (label->idx pred)) (preds preds)) |
3aee6cfd AW |
386 | (match preds |
387 | (() idom) | |
388 | ((pred . preds) | |
4ec3ded0 | 389 | (lp (common-idom idom (label->idx pred)) preds))))))) |
3aee6cfd AW |
390 | ;; This is the iterative O(n^2) fixpoint algorithm, originally from |
391 | ;; Allen and Cocke ("Graph-theoretic constructs for program flow | |
392 | ;; analysis", 1972). See the discussion in Cooper, Harvey, and | |
393 | ;; Kennedy's "A Simple, Fast Dominance Algorithm", 2001. | |
394 | (let iterate ((n 0) (changed? #f)) | |
395 | (cond | |
4ec3ded0 | 396 | ((< n label-count) |
3aee6cfd | 397 | (let ((idom (vector-ref idoms n)) |
4ec3ded0 | 398 | (idom* (compute-idom (vector-ref preds (idx->label n))))) |
3aee6cfd AW |
399 | (cond |
400 | ((eqv? idom idom*) | |
401 | (iterate (1+ n) changed?)) | |
402 | (else | |
403 | (vector-set! idoms n idom*) | |
404 | (iterate (1+ n) #t))))) | |
405 | (changed? | |
406 | (iterate 0 #f)) | |
366eb4d7 AW |
407 | (else idoms))))) |
408 | ||
96b8027c AW |
409 | ;; Compute a vector containing, for each node, a list of the nodes that |
410 | ;; it immediately dominates. These are the "D" edges in the DJ tree. | |
411 | (define (compute-dom-edges idoms) | |
412 | (let ((doms (make-vector (vector-length idoms) '()))) | |
413 | (let lp ((n 0)) | |
414 | (when (< n (vector-length idoms)) | |
415 | (let ((idom (vector-ref idoms n))) | |
416 | (vector-push! doms idom n)) | |
417 | (lp (1+ n)))) | |
418 | doms)) | |
419 | ||
420 | ;; Compute a vector containing, for each node, a list of the successors | |
421 | ;; of that node that are not dominated by that node. These are the "J" | |
422 | ;; edges in the DJ tree. | |
4ec3ded0 | 423 | (define (compute-join-edges preds min-label idoms) |
96b8027c AW |
424 | (define (dominates? n1 n2) |
425 | (or (= n1 n2) | |
426 | (and (< n1 n2) | |
427 | (dominates? n1 (vector-ref idoms n2))))) | |
428 | (let ((joins (make-vector (vector-length idoms) '()))) | |
429 | (let lp ((n 0)) | |
4ec3ded0 | 430 | (when (< n (vector-length idoms)) |
96b8027c | 431 | (for-each (lambda (pred) |
4ec3ded0 AW |
432 | (let ((pred (- pred min-label))) |
433 | (unless (dominates? pred n) | |
434 | (vector-push! joins pred n)))) | |
435 | (vector-ref preds (+ n min-label))) | |
96b8027c AW |
436 | (lp (1+ n)))) |
437 | joins)) | |
438 | ||
439 | ;; Compute a vector containing, for each node, a list of the back edges | |
440 | ;; to that node. If a node is not the entry of a reducible loop, that | |
441 | ;; list is empty. | |
442 | (define (compute-reducible-back-edges joins idoms) | |
443 | (define (dominates? n1 n2) | |
444 | (or (= n1 n2) | |
445 | (and (< n1 n2) | |
446 | (dominates? n1 (vector-ref idoms n2))))) | |
447 | (let ((back-edges (make-vector (vector-length idoms) '()))) | |
448 | (let lp ((n 0)) | |
449 | (when (< n (vector-length joins)) | |
450 | (for-each (lambda (succ) | |
451 | (when (dominates? succ n) | |
452 | (vector-push! back-edges succ n))) | |
453 | (vector-ref joins n)) | |
454 | (lp (1+ n)))) | |
455 | back-edges)) | |
456 | ||
457 | ;; Compute the levels in the dominator tree at which there are | |
458 | ;; irreducible loops, as an integer. If a bit N is set in the integer, | |
459 | ;; that indicates that at level N in the dominator tree, there is at | |
460 | ;; least one irreducible loop. | |
461 | (define (compute-irreducible-dom-levels doms joins idoms dom-levels) | |
366eb4d7 AW |
462 | (define (dominates? n1 n2) |
463 | (or (= n1 n2) | |
464 | (and (< n1 n2) | |
465 | (dominates? n1 (vector-ref idoms n2))))) | |
96b8027c AW |
466 | (let ((pre-order (make-vector (vector-length doms) #f)) |
467 | (last-pre-order (make-vector (vector-length doms) #f)) | |
468 | (res 0) | |
469 | (count 0)) | |
470 | ;; Is MAYBE-PARENT an ancestor of N on the depth-first spanning tree | |
471 | ;; computed from the DJ graph? See Havlak 1997, "Nesting of | |
472 | ;; Reducible and Irreducible Loops". | |
473 | (define (ancestor? a b) | |
474 | (let ((w (vector-ref pre-order a)) | |
475 | (v (vector-ref pre-order b))) | |
476 | (and (<= w v) | |
477 | (<= v (vector-ref last-pre-order w))))) | |
478 | ;; Compute depth-first spanning tree of DJ graph. | |
479 | (define (recurse n) | |
480 | (unless (vector-ref pre-order n) | |
481 | (visit n))) | |
482 | (define (visit n) | |
483 | ;; Pre-order visitation index. | |
484 | (vector-set! pre-order n count) | |
485 | (set! count (1+ count)) | |
486 | (for-each recurse (vector-ref doms n)) | |
487 | (for-each recurse (vector-ref joins n)) | |
488 | ;; Pre-order visitation index of last descendant. | |
489 | (vector-set! last-pre-order (vector-ref pre-order n) (1- count))) | |
490 | ||
491 | (visit 0) | |
492 | ||
493 | (let lp ((n 0)) | |
494 | (when (< n (vector-length joins)) | |
495 | (for-each (lambda (succ) | |
496 | ;; If this join edge is not a loop back edge but it | |
497 | ;; does go to an ancestor on the DFST of the DJ | |
498 | ;; graph, then we have an irreducible loop. | |
499 | (when (and (not (dominates? succ n)) | |
500 | (ancestor? succ n)) | |
501 | (set! res (logior (ash 1 (vector-ref dom-levels succ)))))) | |
502 | (vector-ref joins n)) | |
503 | (lp (1+ n)))) | |
504 | ||
505 | res)) | |
506 | ||
507 | (define (compute-nodes-by-level dom-levels) | |
508 | (let* ((max-level (let lp ((n 0) (max-level 0)) | |
509 | (if (< n (vector-length dom-levels)) | |
510 | (lp (1+ n) (max (vector-ref dom-levels n) max-level)) | |
511 | max-level))) | |
512 | (nodes-by-level (make-vector (1+ max-level) '()))) | |
513 | (let lp ((n (1- (vector-length dom-levels)))) | |
514 | (when (>= n 0) | |
515 | (vector-push! nodes-by-level (vector-ref dom-levels n) n) | |
516 | (lp (1- n)))) | |
517 | nodes-by-level)) | |
518 | ||
519 | ;; Collect all predecessors to the back-nodes that are strictly | |
520 | ;; dominated by the loop header, and mark them as belonging to the loop. | |
521 | ;; If they already have a loop header, that means they are either in a | |
522 | ;; nested loop, or they have already been visited already. | |
4ec3ded0 | 523 | (define (mark-loop-body header back-nodes preds min-label idoms loop-headers) |
96b8027c AW |
524 | (define (strictly-dominates? n1 n2) |
525 | (and (< n1 n2) | |
526 | (let ((idom (vector-ref idoms n2))) | |
527 | (or (= n1 idom) | |
528 | (strictly-dominates? n1 idom))))) | |
529 | (define (visit node) | |
530 | (when (strictly-dominates? header node) | |
531 | (cond | |
532 | ((vector-ref loop-headers node) => visit) | |
533 | (else | |
534 | (vector-set! loop-headers node header) | |
4ec3ded0 AW |
535 | (for-each (lambda (pred) (visit (- pred min-label))) |
536 | (vector-ref preds (+ node min-label))))))) | |
96b8027c AW |
537 | (for-each visit back-nodes)) |
538 | ||
539 | (define (mark-irreducible-loops level idoms dom-levels loop-headers) | |
540 | ;; FIXME: Identify strongly-connected components that are >= LEVEL in | |
541 | ;; the dominator tree, and somehow mark them as irreducible. | |
542 | (warn 'irreducible-loops-at-level level)) | |
543 | ||
544 | ;; "Identifying Loops Using DJ Graphs" by Sreedhar, Gao, and Lee, ACAPS | |
545 | ;; Technical Memo 98, 1995. | |
4ec3ded0 | 546 | (define (identify-loops preds min-label idoms dom-levels) |
96b8027c | 547 | (let* ((doms (compute-dom-edges idoms)) |
4ec3ded0 | 548 | (joins (compute-join-edges preds min-label idoms)) |
96b8027c AW |
549 | (back-edges (compute-reducible-back-edges joins idoms)) |
550 | (irreducible-levels | |
551 | (compute-irreducible-dom-levels doms joins idoms dom-levels)) | |
4ec3ded0 | 552 | (loop-headers (make-vector (vector-length idoms) #f)) |
96b8027c AW |
553 | (nodes-by-level (compute-nodes-by-level dom-levels))) |
554 | (let lp ((level (1- (vector-length nodes-by-level)))) | |
555 | (when (>= level 0) | |
556 | (for-each (lambda (n) | |
557 | (let ((edges (vector-ref back-edges n))) | |
558 | (unless (null? edges) | |
4ec3ded0 AW |
559 | (mark-loop-body n edges preds min-label |
560 | idoms loop-headers)))) | |
96b8027c AW |
561 | (vector-ref nodes-by-level level)) |
562 | (when (logbit? level irreducible-levels) | |
563 | (mark-irreducible-loops level idoms dom-levels loop-headers)) | |
564 | (lp (1- level)))) | |
565 | loop-headers)) | |
366eb4d7 | 566 | |
4ec3ded0 AW |
567 | (define (analyze-dominators dfg min-label label-count) |
568 | (let* ((idoms (compute-idoms (dfg-preds dfg) min-label label-count)) | |
569 | (dom-levels (compute-dom-levels idoms)) | |
570 | (loop-headers (identify-loops (dfg-preds dfg) min-label idoms dom-levels))) | |
571 | (make-dominator-analysis min-label idoms dom-levels loop-headers #f))) | |
3aee6cfd | 572 | |
db11440d AW |
573 | |
574 | ;; Compute the maximum fixed point of the data-flow constraint problem. | |
575 | ;; | |
576 | ;; This always completes, as the graph is finite and the in and out sets | |
577 | ;; are complete semi-lattices. If the graph is reducible and the blocks | |
578 | ;; are sorted in reverse post-order, this completes in a maximum of LC + | |
579 | ;; 2 iterations, where LC is the loop connectedness number. See Hecht | |
580 | ;; and Ullman, "Analysis of a simple algorithm for global flow | |
581 | ;; problems", POPL 1973, or the recent summary in "Notes on graph | |
582 | ;; algorithms used in optimizing compilers", Offner 2013. | |
583 | (define (compute-maximum-fixed-point preds inv outv killv genv union?) | |
584 | (define (bitvector-copy! dst src) | |
585 | (bitvector-fill! dst #f) | |
586 | (bit-set*! dst src #t)) | |
587 | (define (bitvector-meet! accum src) | |
588 | (bit-set*! accum src union?)) | |
589 | (let lp ((n 0) (changed? #f)) | |
590 | (cond | |
591 | ((< n (vector-length preds)) | |
592 | (let ((in (vector-ref inv n)) | |
593 | (out (vector-ref outv n)) | |
594 | (kill (vector-ref killv n)) | |
595 | (gen (vector-ref genv n))) | |
596 | (let ((out-count (or changed? (bit-count #t out)))) | |
597 | (for-each | |
598 | (lambda (pred) | |
599 | (bitvector-meet! in (vector-ref outv pred))) | |
600 | (vector-ref preds n)) | |
601 | (bitvector-copy! out in) | |
602 | (for-each (cut bitvector-set! out <> #f) kill) | |
603 | (for-each (cut bitvector-set! out <> #t) gen) | |
604 | (lp (1+ n) | |
605 | (or changed? (not (eqv? out-count (bit-count #t out)))))))) | |
606 | (changed? | |
607 | (lp 0 #f))))) | |
608 | ||
609 | ;; Data-flow analysis. | |
610 | (define-record-type $dfa | |
21a528fd | 611 | (make-dfa min-label min-var var-count in out) |
db11440d | 612 | dfa? |
21a528fd | 613 | ;; Minimum label in this function. |
a57f6e1e | 614 | (min-label dfa-min-label) |
7c4977e6 AW |
615 | ;; Minimum var in this function. |
616 | (min-var dfa-min-var) | |
21a528fd | 617 | ;; Var count in this function. |
7c4977e6 | 618 | (var-count dfa-var-count) |
db11440d AW |
619 | ;; Vector of k-idx -> bitvector |
620 | (in dfa-in) | |
621 | ;; Vector of k-idx -> bitvector | |
622 | (out dfa-out)) | |
623 | ||
624 | (define (dfa-k-idx dfa k) | |
21a528fd | 625 | (- k (dfa-min-label dfa))) |
db11440d AW |
626 | |
627 | (define (dfa-k-sym dfa idx) | |
21a528fd | 628 | (+ idx (dfa-min-label dfa))) |
db11440d AW |
629 | |
630 | (define (dfa-k-count dfa) | |
21a528fd | 631 | (vector-length (dfa-in dfa))) |
db11440d AW |
632 | |
633 | (define (dfa-var-idx dfa var) | |
7c4977e6 AW |
634 | (let ((idx (- var (dfa-min-var dfa)))) |
635 | (unless (< -1 idx (dfa-var-count dfa)) | |
636 | (error "var out of range" var)) | |
637 | idx)) | |
db11440d | 638 | |
db11440d | 639 | (define (dfa-var-sym dfa idx) |
7c4977e6 AW |
640 | (unless (< -1 idx (dfa-var-count dfa)) |
641 | (error "idx out of range" idx)) | |
642 | (+ idx (dfa-min-var dfa))) | |
db11440d AW |
643 | |
644 | (define (dfa-k-in dfa idx) | |
645 | (vector-ref (dfa-in dfa) idx)) | |
646 | ||
647 | (define (dfa-k-out dfa idx) | |
648 | (vector-ref (dfa-out dfa) idx)) | |
649 | ||
5bff3125 | 650 | (define (compute-live-variables fun dfg) |
7c4977e6 AW |
651 | (unless (and (= (vector-length (dfg-uses dfg)) (dfg-var-count dfg)) |
652 | (= (vector-length (dfg-cont-table dfg)) (dfg-label-count dfg))) | |
653 | (error "function needs renumbering")) | |
a7324faf AW |
654 | (let* ((min-label (dfg-min-label dfg)) |
655 | (nlabels (dfg-label-count dfg)) | |
656 | (min-var (dfg-min-var dfg)) | |
a8430ab1 | 657 | (nvars (dfg-var-count dfg)) |
a7324faf AW |
658 | (usev (make-vector nlabels '())) |
659 | (defv (make-vector nlabels '())) | |
660 | (live-in (make-vector nlabels #f)) | |
661 | (live-out (make-vector nlabels #f))) | |
662 | (call-with-values | |
663 | (lambda () | |
664 | (analyze-reverse-control-flow fun dfg min-label nlabels)) | |
21a528fd | 665 | (lambda (k-map succs) |
a7324faf AW |
666 | (define (var->idx var) (- var min-var)) |
667 | (define (idx->var idx) (+ idx min-var)) | |
668 | (define (label->idx label) | |
669 | (vector-ref k-map (- label min-label))) | |
670 | ||
671 | ;; Initialize defv and usev. | |
672 | (let ((defs (dfg-defs dfg)) | |
673 | (uses (dfg-uses dfg))) | |
674 | (let lp ((n 0)) | |
675 | (when (< n (vector-length defs)) | |
676 | (let ((def (vector-ref defs n))) | |
677 | (unless def | |
678 | (error "internal error -- var array not packed")) | |
679 | (for-each (lambda (def) | |
680 | (vector-push! defv (label->idx def) n)) | |
681 | (lookup-predecessors def dfg)) | |
682 | (for-each (lambda (use) | |
683 | (vector-push! usev (label->idx use) n)) | |
684 | (vector-ref uses n)) | |
685 | (lp (1+ n)))))) | |
686 | ||
687 | ;; Initialize live-in and live-out sets. | |
688 | (let lp ((n 0)) | |
689 | (when (< n (vector-length live-out)) | |
690 | (vector-set! live-in n (make-bitvector nvars #f)) | |
691 | (vector-set! live-out n (make-bitvector nvars #f)) | |
692 | (lp (1+ n)))) | |
693 | ||
694 | ;; Liveness is a reverse data-flow problem, so we give | |
695 | ;; compute-maximum-fixed-point a reversed graph, swapping in for | |
696 | ;; out, usev for defv, and using successors instead of | |
697 | ;; predecessors. Continuation 0 is ktail. | |
698 | (compute-maximum-fixed-point succs live-out live-in defv usev #t) | |
699 | ||
21a528fd AW |
700 | ;; Now rewrite the live-in and live-out sets to be indexed by |
701 | ;; (LABEL - MIN-LABEL). | |
702 | (let ((live-in* (make-vector nlabels #f)) | |
703 | (live-out* (make-vector nlabels #f))) | |
704 | (let lp ((idx 0)) | |
705 | (when (< idx nlabels) | |
706 | (let ((dfa-idx (vector-ref k-map idx))) | |
707 | (vector-set! live-in* idx (vector-ref live-in dfa-idx)) | |
708 | (vector-set! live-out* idx (vector-ref live-out dfa-idx)) | |
709 | (lp (1+ idx))))) | |
710 | ||
711 | (make-dfa min-label min-var nvars live-in* live-out*)))))) | |
db11440d AW |
712 | |
713 | (define (print-dfa dfa) | |
714 | (match dfa | |
21a528fd | 715 | (($ $dfa min-label min-var var-count in out) |
db11440d AW |
716 | (define (print-var-set bv) |
717 | (let lp ((n 0)) | |
718 | (let ((n (bit-position #t bv n))) | |
719 | (when n | |
7c4977e6 | 720 | (format #t " ~A" (+ n min-var)) |
db11440d AW |
721 | (lp (1+ n)))))) |
722 | (let lp ((n 0)) | |
21a528fd AW |
723 | (when (< n (vector-length in)) |
724 | (format #t "~A:\n" (+ n min-label)) | |
db11440d AW |
725 | (format #t " in:") |
726 | (print-var-set (vector-ref in n)) | |
727 | (newline) | |
728 | (format #t " out:") | |
729 | (print-var-set (vector-ref out n)) | |
730 | (newline) | |
731 | (lp (1+ n))))))) | |
732 | ||
5e897908 AW |
733 | (define (compute-label-and-var-ranges fun global?) |
734 | (define (min* a b) | |
735 | (if b (min a b) a)) | |
405805fb AW |
736 | (define-syntax-rule (do-fold make-cont-folder) |
737 | ((make-cont-folder min-label max-label label-count | |
545274a0 AW |
738 | min-var max-var var-count) |
739 | (lambda (label cont | |
740 | min-label max-label label-count | |
741 | min-var max-var var-count) | |
742 | (let ((min-label (min* label min-label)) | |
743 | (max-label (max label max-label))) | |
744 | (define (visit-letrec body min-var max-var var-count) | |
745 | (match body | |
746 | (($ $letk conts body) | |
747 | (visit-letrec body min-var max-var var-count)) | |
748 | (($ $letrec names vars funs body) | |
749 | (visit-letrec body | |
750 | (cond (min-var (fold min min-var vars)) | |
751 | ((pair? vars) (fold min (car vars) (cdr vars))) | |
752 | (else min-var)) | |
753 | (fold max max-var vars) | |
754 | (+ var-count (length vars)))) | |
755 | (($ $continue) (values min-var max-var var-count)))) | |
756 | (match cont | |
757 | (($ $kargs names vars body) | |
758 | (call-with-values | |
759 | (lambda () | |
760 | (if global? | |
761 | (visit-letrec body min-var max-var var-count) | |
762 | (values min-var max-var var-count))) | |
763 | (lambda (min-var max-var var-count) | |
764 | (values min-label max-label (1+ label-count) | |
765 | (cond (min-var (fold min min-var vars)) | |
766 | ((pair? vars) (fold min (car vars) (cdr vars))) | |
767 | (else min-var)) | |
768 | (fold max max-var vars) | |
769 | (+ var-count (length vars)))))) | |
8320f504 | 770 | (($ $kfun src meta self) |
545274a0 AW |
771 | (values min-label max-label (1+ label-count) |
772 | (min* self min-var) (max self max-var) (1+ var-count))) | |
773 | (_ (values min-label max-label (1+ label-count) | |
774 | min-var max-var var-count))))) | |
775 | fun | |
776 | #f -1 0 #f -1 0)) | |
777 | (if global? | |
405805fb AW |
778 | (do-fold make-global-cont-folder) |
779 | (do-fold make-local-cont-folder))) | |
5e897908 | 780 | |
6e8ad823 | 781 | (define* (compute-dfg fun #:key (global? #t)) |
a16af113 AW |
782 | (call-with-values (lambda () (compute-label-and-var-ranges fun global?)) |
783 | (lambda (min-label max-label label-count min-var max-var var-count) | |
784 | (when (or (zero? label-count) (zero? var-count)) | |
785 | (error "internal error (no vars or labels for fun?)")) | |
786 | (let* ((nlabels (- (1+ max-label) min-label)) | |
787 | (nvars (- (1+ max-var) min-var)) | |
788 | (conts (make-vector nlabels #f)) | |
789 | (preds (make-vector nlabels '())) | |
790 | (defs (make-vector nvars #f)) | |
791 | (uses (make-vector nvars '())) | |
792 | (scopes (make-vector nlabels #f)) | |
793 | (scope-levels (make-vector nlabels #f))) | |
794 | (define (var->idx var) (- var min-var)) | |
795 | (define (label->idx label) (- label min-label)) | |
796 | ||
797 | (define (add-def! var def-k) | |
798 | (vector-set! defs (var->idx var) def-k)) | |
799 | (define (add-use! var use-k) | |
800 | (vector-push! uses (var->idx var) use-k)) | |
801 | ||
802 | (define* (declare-block! label cont parent | |
803 | #:optional (level | |
804 | (1+ (vector-ref | |
805 | scope-levels | |
806 | (label->idx parent))))) | |
807 | (vector-set! conts (label->idx label) cont) | |
808 | (vector-set! scopes (label->idx label) parent) | |
809 | (vector-set! scope-levels (label->idx label) level)) | |
810 | ||
811 | (define (link-blocks! pred succ) | |
812 | (vector-push! preds (label->idx succ) pred)) | |
813 | ||
814 | (define (visit-cont cont label) | |
815 | (match cont | |
816 | (($ $kargs names syms body) | |
817 | (for-each (cut add-def! <> label) syms) | |
818 | (visit-term body label)) | |
819 | (($ $kif kt kf) | |
820 | (link-blocks! label kt) | |
821 | (link-blocks! label kf)) | |
822 | (($ $kreceive arity k) | |
823 | (link-blocks! label k)))) | |
824 | ||
825 | (define (visit-term term label) | |
826 | (match term | |
827 | (($ $letk (($ $cont k cont) ...) body) | |
828 | ;; Set up recursive environment before visiting cont bodies. | |
829 | (for-each/2 (lambda (cont k) | |
830 | (declare-block! k cont label)) | |
831 | cont k) | |
832 | (for-each/2 visit-cont cont k) | |
833 | (visit-term body label)) | |
834 | (($ $letrec names syms funs body) | |
835 | (unless global? | |
836 | (error "$letrec should not be present when building a local DFG")) | |
837 | (for-each (cut add-def! <> label) syms) | |
838 | (for-each (lambda (fun) | |
839 | (match fun | |
840 | (($ $fun free body) | |
841 | (visit-fun body)))) | |
842 | funs) | |
843 | (visit-term body label)) | |
844 | (($ $continue k src exp) | |
845 | (link-blocks! label k) | |
846 | (visit-exp exp label)))) | |
847 | ||
848 | (define (visit-exp exp label) | |
849 | (define (use! sym) | |
850 | (add-use! sym label)) | |
851 | (match exp | |
cf8bb037 | 852 | ((or ($ $void) ($ $const) ($ $prim) ($ $closure)) #f) |
a16af113 AW |
853 | (($ $call proc args) |
854 | (use! proc) | |
855 | (for-each use! args)) | |
856 | (($ $callk k proc args) | |
857 | (use! proc) | |
858 | (for-each use! args)) | |
859 | (($ $primcall name args) | |
860 | (for-each use! args)) | |
861 | (($ $values args) | |
862 | (for-each use! args)) | |
863 | (($ $prompt escape? tag handler) | |
864 | (use! tag) | |
865 | (link-blocks! label handler)) | |
866 | (($ $fun free body) | |
867 | (when global? | |
868 | (visit-fun body))))) | |
869 | ||
870 | (define (visit-clause clause kfun) | |
871 | (match clause | |
872 | (#f #t) | |
873 | (($ $cont kclause | |
874 | (and clause ($ $kclause arity ($ $cont kbody body) | |
875 | alternate))) | |
876 | (declare-block! kclause clause kfun) | |
877 | (link-blocks! kfun kclause) | |
878 | ||
879 | (declare-block! kbody body kclause) | |
880 | (link-blocks! kclause kbody) | |
881 | ||
882 | (visit-cont body kbody) | |
883 | (visit-clause alternate kfun)))) | |
884 | ||
885 | (define (visit-fun fun) | |
886 | (match fun | |
887 | (($ $cont kfun | |
888 | (and cont | |
889 | ($ $kfun src meta self ($ $cont ktail tail) clause))) | |
890 | (declare-block! kfun cont #f 0) | |
891 | (add-def! self kfun) | |
892 | (declare-block! ktail tail kfun) | |
893 | (visit-clause clause kfun)))) | |
894 | ||
895 | (visit-fun fun) | |
896 | ||
897 | (make-dfg conts preds defs uses scopes scope-levels | |
898 | min-label max-label label-count | |
899 | min-var max-var var-count))))) | |
3e1b97c1 | 900 | |
fb512cac AW |
901 | (define* (dump-dfg dfg #:optional (port (current-output-port))) |
902 | (let ((min-label (dfg-min-label dfg)) | |
903 | (min-var (dfg-min-var dfg))) | |
904 | (define (label->idx label) (- label min-label)) | |
905 | (define (idx->label idx) (+ idx min-label)) | |
906 | (define (var->idx var) (- var min-var)) | |
907 | (define (idx->var idx) (+ idx min-var)) | |
908 | ||
909 | (let lp ((label (dfg-min-label dfg))) | |
51177f35 | 910 | (when (<= label (dfg-max-label dfg)) |
fb512cac AW |
911 | (let ((cont (vector-ref (dfg-cont-table dfg) (label->idx label)))) |
912 | (when cont | |
913 | (unless (equal? (lookup-predecessors label dfg) (list (1- label))) | |
914 | (newline port)) | |
915 | (format port "k~a:~8t" label) | |
916 | (match cont | |
917 | (($ $kif kt kf) | |
918 | (format port "$kif k~a k~a\n" kt kf)) | |
919 | (($ $kreceive arity k) | |
920 | (format port "$kreceive ~a k~a\n" arity k)) | |
921 | (($ $kfun src meta self tail clause) | |
922 | (format port "$kfun ~a ~a v~a\n" src meta self)) | |
923 | (($ $ktail) | |
924 | (format port "$ktail\n")) | |
925 | (($ $kclause arity ($ $cont kbody) alternate) | |
926 | (format port "$kclause ~a k~a" arity kbody) | |
927 | (match alternate | |
928 | (#f #f) | |
929 | (($ $cont kalt) (format port " -> k~a" kalt))) | |
930 | (newline port)) | |
931 | (($ $kargs names vars term) | |
932 | (unless (null? vars) | |
933 | (format port "v~a[~a]~:{ v~a[~a]~}: " | |
934 | (car vars) (car names) (map list (cdr vars) (cdr names)))) | |
935 | (match (find-call term) | |
936 | (($ $continue k src exp) | |
937 | (match exp | |
938 | (($ $void) (format port "void")) | |
939 | (($ $const val) (format port "const ~@y" val)) | |
940 | (($ $prim name) (format port "prim ~a" name)) | |
941 | (($ $fun free ($ $cont kbody)) (format port "fun k~a" kbody)) | |
942 | (($ $closure label nfree) (format port "closure k~a (~a free)" label nfree)) | |
943 | (($ $call proc args) (format port "call~{ v~a~}" (cons proc args))) | |
944 | (($ $callk k proc args) (format port "callk k~a~{ v~a~}" k (cons proc args))) | |
945 | (($ $primcall name args) (format port "~a~{ v~a~}" name args)) | |
946 | (($ $values args) (format port "values~{ v~a~}" args)) | |
947 | (($ $prompt escape? tag handler) (format port "prompt ~a v~a k~a" escape? tag handler))) | |
948 | (unless (= k (1+ label)) | |
949 | (format port " -> k~a" k)) | |
950 | (newline port)))))) | |
951 | (lp (1+ label))))))) | |
952 | ||
3e1b97c1 AW |
953 | (define-syntax-rule (with-fresh-name-state-from-dfg dfg body ...) |
954 | (parameterize ((label-counter (1+ (dfg-max-label dfg))) | |
955 | (var-counter (1+ (dfg-max-var dfg)))) | |
956 | body ...)) | |
5e897908 | 957 | |
f49e994b AW |
958 | (define (lookup-cont label dfg) |
959 | (let ((res (vector-ref (dfg-cont-table dfg) (- label (dfg-min-label dfg))))) | |
960 | (unless res | |
961 | (error "Unknown continuation!" label)) | |
962 | res)) | |
963 | ||
5fc40391 AW |
964 | (define (lookup-predecessors k dfg) |
965 | (vector-ref (dfg-preds dfg) (- k (dfg-min-label dfg)))) | |
966 | ||
967 | (define (lookup-successors k dfg) | |
2c3c086e AW |
968 | (let ((cont (vector-ref (dfg-cont-table dfg) (- k (dfg-min-label dfg))))) |
969 | (visit-cont-successors list cont))) | |
6e8ad823 | 970 | |
5e897908 | 971 | (define (lookup-def var dfg) |
f49e994b | 972 | (vector-ref (dfg-defs dfg) (- var (dfg-min-var dfg)))) |
6e8ad823 | 973 | |
5e897908 | 974 | (define (lookup-uses var dfg) |
f49e994b | 975 | (vector-ref (dfg-uses dfg) (- var (dfg-min-var dfg)))) |
6e8ad823 | 976 | |
c8ad7426 | 977 | (define (lookup-block-scope k dfg) |
5fc40391 | 978 | (vector-ref (dfg-scopes dfg) (- k (dfg-min-label dfg)))) |
f22979db | 979 | |
5fc40391 AW |
980 | (define (lookup-scope-level k dfg) |
981 | (vector-ref (dfg-scope-levels dfg) (- k (dfg-min-label dfg)))) | |
f22979db | 982 | |
6e8ad823 | 983 | (define (find-defining-term sym dfg) |
f22979db | 984 | (match (lookup-predecessors (lookup-def sym dfg) dfg) |
6e8ad823 | 985 | ((def-exp-k) |
fbdb69b2 | 986 | (lookup-cont def-exp-k dfg)) |
6e8ad823 AW |
987 | (else #f))) |
988 | ||
989 | (define (find-call term) | |
990 | (match term | |
991 | (($ $kargs names syms body) (find-call body)) | |
992 | (($ $letk conts body) (find-call body)) | |
993 | (($ $letrec names syms funs body) (find-call body)) | |
994 | (($ $continue) term))) | |
995 | ||
996 | (define (call-expression call) | |
997 | (match call | |
6e422a35 | 998 | (($ $continue k src exp) exp))) |
6e8ad823 AW |
999 | |
1000 | (define (find-expression term) | |
1001 | (call-expression (find-call term))) | |
1002 | ||
1003 | (define (find-defining-expression sym dfg) | |
1004 | (match (find-defining-term sym dfg) | |
1005 | (#f #f) | |
36527695 | 1006 | (($ $kreceive) #f) |
f22979db | 1007 | (($ $kclause) #f) |
6e8ad823 AW |
1008 | (term (find-expression term)))) |
1009 | ||
1010 | (define (find-constant-value sym dfg) | |
1011 | (match (find-defining-expression sym dfg) | |
1012 | (($ $const val) | |
1013 | (values #t val)) | |
6e422a35 | 1014 | (($ $continue k src ($ $void)) |
6e8ad823 AW |
1015 | (values #t *unspecified*)) |
1016 | (else | |
1017 | (values #f #f)))) | |
1018 | ||
36aeda5b | 1019 | (define (constant-needs-allocation? var val dfg) |
607fe5a6 AW |
1020 | (define (immediate-u8? val) |
1021 | (and (integer? val) (exact? val) (<= 0 val 255))) | |
1022 | ||
6e8ad823 AW |
1023 | (define (find-exp term) |
1024 | (match term | |
36aeda5b | 1025 | (($ $kargs names vars body) (find-exp body)) |
6e8ad823 AW |
1026 | (($ $letk conts body) (find-exp body)) |
1027 | (else term))) | |
f49e994b AW |
1028 | |
1029 | (or-map | |
1030 | (lambda (use) | |
1031 | (match (find-expression (lookup-cont use dfg)) | |
1032 | (($ $call) #f) | |
1033 | (($ $callk) #f) | |
1034 | (($ $values) #f) | |
1035 | (($ $primcall 'free-ref (closure slot)) | |
36aeda5b | 1036 | (eq? var closure)) |
f49e994b | 1037 | (($ $primcall 'free-set! (closure slot value)) |
36aeda5b | 1038 | (or (eq? var closure) (eq? var value))) |
f49e994b | 1039 | (($ $primcall 'cache-current-module! (mod . _)) |
36aeda5b | 1040 | (eq? var mod)) |
f49e994b AW |
1041 | (($ $primcall 'cached-toplevel-box _) |
1042 | #f) | |
1043 | (($ $primcall 'cached-module-box _) | |
1044 | #f) | |
1045 | (($ $primcall 'resolve (name bound?)) | |
36aeda5b | 1046 | (eq? var name)) |
f49e994b | 1047 | (($ $primcall 'make-vector/immediate (len init)) |
36aeda5b | 1048 | (eq? var init)) |
f49e994b | 1049 | (($ $primcall 'vector-ref/immediate (v i)) |
36aeda5b | 1050 | (eq? var v)) |
f49e994b | 1051 | (($ $primcall 'vector-set!/immediate (v i x)) |
36aeda5b | 1052 | (or (eq? var v) (eq? var x))) |
f49e994b | 1053 | (($ $primcall 'allocate-struct/immediate (vtable nfields)) |
36aeda5b | 1054 | (eq? var vtable)) |
f49e994b | 1055 | (($ $primcall 'struct-ref/immediate (s n)) |
36aeda5b | 1056 | (eq? var s)) |
f49e994b | 1057 | (($ $primcall 'struct-set!/immediate (s n x)) |
36aeda5b | 1058 | (or (eq? var s) (eq? var x))) |
f49e994b AW |
1059 | (($ $primcall 'builtin-ref (idx)) |
1060 | #f) | |
1061 | (_ #t))) | |
36aeda5b | 1062 | (vector-ref (dfg-uses dfg) (- var (dfg-min-var dfg))))) |
6e8ad823 | 1063 | |
5e897908 AW |
1064 | (define (continuation-scope-contains? scope-k k dfg) |
1065 | (let ((scope-level (lookup-scope-level scope-k dfg))) | |
f22979db AW |
1066 | (let lp ((k k)) |
1067 | (or (eq? scope-k k) | |
5fc40391 AW |
1068 | (and (< scope-level (lookup-scope-level k dfg)) |
1069 | (lp (lookup-block-scope k dfg))))))) | |
f22979db | 1070 | |
f22979db | 1071 | (define (continuation-bound-in? k use-k dfg) |
21d6d183 | 1072 | (continuation-scope-contains? (lookup-block-scope k dfg) use-k dfg)) |
d51fb1e6 AW |
1073 | |
1074 | (define (variable-free-in? var k dfg) | |
5e897908 AW |
1075 | (or-map (lambda (use) |
1076 | (continuation-scope-contains? k use dfg)) | |
1077 | (lookup-uses var dfg))) | |
6e8ad823 | 1078 | |
e636f424 | 1079 | ;; A continuation is a control point if it has multiple predecessors, or |
a3a45279 | 1080 | ;; if its single predecessor does not have a single successor. |
e636f424 AW |
1081 | (define (control-point? k dfg) |
1082 | (match (lookup-predecessors k dfg) | |
1083 | ((pred) | |
2c3c086e AW |
1084 | (let ((cont (vector-ref (dfg-cont-table dfg) |
1085 | (- pred (dfg-min-label dfg))))) | |
1086 | (visit-cont-successors (case-lambda | |
1087 | (() #t) | |
1088 | ((succ0) #f) | |
1089 | ((succ1 succ2) #t)) | |
1090 | cont))) | |
e636f424 | 1091 | (_ #t))) |
6e8ad823 AW |
1092 | |
1093 | (define (lookup-bound-syms k dfg) | |
fbdb69b2 AW |
1094 | (match (lookup-cont k dfg) |
1095 | (($ $kargs names syms body) | |
1096 | syms))) |