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cf10678f AW |
1 | ;;; TREE-IL -> GLIL compiler |
2 | ||
3 | ;; Copyright (C) 2001,2008,2009 Free Software Foundation, Inc. | |
4 | ||
53befeb7 NJ |
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 | |
cf10678f AW |
18 | |
19 | ;;; Code: | |
20 | ||
21 | (define-module (language tree-il analyze) | |
66d3e9a3 | 22 | #:use-module (srfi srfi-1) |
4b856371 | 23 | #:use-module (srfi srfi-9) |
cf10678f | 24 | #:use-module (system base syntax) |
4b856371 | 25 | #:use-module (system base message) |
af5ed549 | 26 | #:use-module (system vm program) |
cf10678f | 27 | #:use-module (language tree-il) |
99480e11 | 28 | #:use-module (system base pmatch) |
4b856371 | 29 | #:export (analyze-lexicals |
48b1db75 LC |
30 | analyze-tree |
31 | unused-variable-analysis | |
ae03cf1f LC |
32 | unbound-variable-analysis |
33 | arity-analysis)) | |
cf10678f | 34 | |
66d3e9a3 AW |
35 | ;; Allocation is the process of assigning storage locations for lexical |
36 | ;; variables. A lexical variable has a distinct "address", or storage | |
37 | ;; location, for each procedure in which it is referenced. | |
38 | ;; | |
39 | ;; A variable is "local", i.e., allocated on the stack, if it is | |
40 | ;; referenced from within the procedure that defined it. Otherwise it is | |
41 | ;; a "closure" variable. For example: | |
42 | ;; | |
43 | ;; (lambda (a) a) ; a will be local | |
44 | ;; `a' is local to the procedure. | |
45 | ;; | |
46 | ;; (lambda (a) (lambda () a)) | |
47 | ;; `a' is local to the outer procedure, but a closure variable with | |
48 | ;; respect to the inner procedure. | |
49 | ;; | |
50 | ;; If a variable is ever assigned, it needs to be heap-allocated | |
51 | ;; ("boxed"). This is so that closures and continuations capture the | |
52 | ;; variable's identity, not just one of the values it may have over the | |
53 | ;; course of program execution. If the variable is never assigned, there | |
54 | ;; is no distinction between value and identity, so closing over its | |
55 | ;; identity (whether through closures or continuations) can make a copy | |
56 | ;; of its value instead. | |
57 | ;; | |
58 | ;; Local variables are stored on the stack within a procedure's call | |
59 | ;; frame. Their index into the stack is determined from their linear | |
60 | ;; postion within a procedure's binding path: | |
cf10678f AW |
61 | ;; (let (0 1) |
62 | ;; (let (2 3) ...) | |
63 | ;; (let (2) ...)) | |
64 | ;; (let (2 3 4) ...)) | |
65 | ;; etc. | |
66 | ;; | |
5af166bd AW |
67 | ;; This algorithm has the problem that variables are only allocated |
68 | ;; indices at the end of the binding path. If variables bound early in | |
69 | ;; the path are not used in later portions of the path, their indices | |
70 | ;; will not be recycled. This problem is particularly egregious in the | |
71 | ;; expansion of `or': | |
72 | ;; | |
73 | ;; (or x y z) | |
74 | ;; -> (let ((a x)) (if a a (let ((b y)) (if b b z)))) | |
75 | ;; | |
76 | ;; As you can see, the `a' binding is only used in the ephemeral `then' | |
77 | ;; clause of the first `if', but its index would be reserved for the | |
78 | ;; whole of the `or' expansion. So we have a hack for this specific | |
79 | ;; case. A proper solution would be some sort of liveness analysis, and | |
80 | ;; not our linear allocation algorithm. | |
81 | ;; | |
66d3e9a3 AW |
82 | ;; Closure variables are captured when a closure is created, and stored |
83 | ;; in a vector. Each closure variable has a unique index into that | |
84 | ;; vector. | |
85 | ;; | |
9059993f AW |
86 | ;; There is one more complication. Procedures bound by <fix> may, in |
87 | ;; some cases, be rendered inline to their parent procedure. That is to | |
88 | ;; say, | |
89 | ;; | |
90 | ;; (letrec ((lp (lambda () (lp)))) (lp)) | |
91 | ;; => (fix ((lp (lambda () (lp)))) (lp)) | |
92 | ;; => goto FIX-BODY; LP: goto LP; FIX-BODY: goto LP; | |
93 | ;; ^ jump over the loop ^ the fixpoint lp ^ starting off the loop | |
94 | ;; | |
95 | ;; The upshot is that we don't have to allocate any space for the `lp' | |
96 | ;; closure at all, as it can be rendered inline as a loop. So there is | |
97 | ;; another kind of allocation, "label allocation", in which the | |
98 | ;; procedure is simply a label, placed at the start of the lambda body. | |
99 | ;; The label is the gensym under which the lambda expression is bound. | |
100 | ;; | |
101 | ;; The analyzer checks to see that the label is called with the correct | |
102 | ;; number of arguments. Calls to labels compile to rename + goto. | |
103 | ;; Lambda, the ultimate goto! | |
104 | ;; | |
66d3e9a3 AW |
105 | ;; |
106 | ;; The return value of `analyze-lexicals' is a hash table, the | |
107 | ;; "allocation". | |
108 | ;; | |
109 | ;; The allocation maps gensyms -- recall that each lexically bound | |
110 | ;; variable has a unique gensym -- to storage locations ("addresses"). | |
111 | ;; Since one gensym may have many storage locations, if it is referenced | |
112 | ;; in many procedures, it is a two-level map. | |
113 | ;; | |
114 | ;; The allocation also stored information on how many local variables | |
9059993f AW |
115 | ;; need to be allocated for each procedure, lexicals that have been |
116 | ;; translated into labels, and information on what free variables to | |
117 | ;; capture from its lexical parent procedure. | |
66d3e9a3 | 118 | ;; |
8a4ca0ea AW |
119 | ;; In addition, we have a conflation: while we're traversing the code, |
120 | ;; recording information to pass to the compiler, we take the | |
121 | ;; opportunity to generate labels for each lambda-case clause, so that | |
122 | ;; generated code can skip argument checks at runtime if they match at | |
123 | ;; compile-time. | |
124 | ;; | |
66d3e9a3 AW |
125 | ;; That is: |
126 | ;; | |
127 | ;; sym -> {lambda -> address} | |
8a4ca0ea AW |
128 | ;; lambda -> (labels . free-locs) |
129 | ;; lambda-case -> (gensym . nlocs) | |
66d3e9a3 | 130 | ;; |
9059993f | 131 | ;; address ::= (local? boxed? . index) |
8a4ca0ea | 132 | ;; labels ::= ((sym . lambda) ...) |
66d3e9a3 AW |
133 | ;; free-locs ::= ((sym0 . address0) (sym1 . address1) ...) |
134 | ;; free variable addresses are relative to parent proc. | |
135 | ||
136 | (define (make-hashq k v) | |
137 | (let ((res (make-hash-table))) | |
138 | (hashq-set! res k v) | |
139 | res)) | |
cf10678f AW |
140 | |
141 | (define (analyze-lexicals x) | |
66d3e9a3 AW |
142 | ;; bound-vars: lambda -> (sym ...) |
143 | ;; all identifiers bound within a lambda | |
9059993f | 144 | (define bound-vars (make-hash-table)) |
66d3e9a3 AW |
145 | ;; free-vars: lambda -> (sym ...) |
146 | ;; all identifiers referenced in a lambda, but not bound | |
147 | ;; NB, this includes identifiers referenced by contained lambdas | |
9059993f | 148 | (define free-vars (make-hash-table)) |
66d3e9a3 AW |
149 | ;; assigned: sym -> #t |
150 | ;; variables that are assigned | |
d97b69d9 | 151 | (define assigned (make-hash-table)) |
5af166bd | 152 | ;; refcounts: sym -> count |
66d3e9a3 | 153 | ;; allows us to detect the or-expansion in O(1) time |
9059993f | 154 | (define refcounts (make-hash-table)) |
8a4ca0ea | 155 | ;; labels: sym -> lambda |
9059993f | 156 | ;; for determining if fixed-point procedures can be rendered as |
8a4ca0ea | 157 | ;; labels. |
9059993f AW |
158 | (define labels (make-hash-table)) |
159 | ||
66d3e9a3 | 160 | ;; returns variables referenced in expr |
d97b69d9 AW |
161 | (define (analyze! x proc labels-in-proc tail? tail-call-args) |
162 | (define (step y) (analyze! y proc labels-in-proc #f #f)) | |
163 | (define (step-tail y) (analyze! y proc labels-in-proc tail? #f)) | |
164 | (define (step-tail-call y args) (analyze! y proc labels-in-proc #f | |
165 | (and tail? args))) | |
166 | (define (recur/labels x new-proc labels) | |
167 | (analyze! x new-proc (append labels labels-in-proc) #t #f)) | |
168 | (define (recur x new-proc) (analyze! x new-proc '() tail? #f)) | |
cf10678f AW |
169 | (record-case x |
170 | ((<application> proc args) | |
d97b69d9 AW |
171 | (apply lset-union eq? (step-tail-call proc args) |
172 | (map step args))) | |
cf10678f AW |
173 | |
174 | ((<conditional> test then else) | |
d97b69d9 | 175 | (lset-union eq? (step test) (step-tail then) (step-tail else))) |
cf10678f | 176 | |
e5f5113c | 177 | ((<lexical-ref> gensym) |
5af166bd | 178 | (hashq-set! refcounts gensym (1+ (hashq-ref refcounts gensym 0))) |
d97b69d9 AW |
179 | (if (not (and tail-call-args |
180 | (memq gensym labels-in-proc) | |
8a4ca0ea AW |
181 | (let ((p (hashq-ref labels gensym))) |
182 | (and p | |
183 | (let lp ((c (lambda-body p))) | |
184 | (and c (lambda-case? c) | |
185 | (or | |
186 | ;; for now prohibit optional & | |
187 | ;; keyword arguments; can relax this | |
188 | ;; restriction later | |
189 | (and (= (length (lambda-case-req c)) | |
190 | (length tail-call-args)) | |
191 | (not (lambda-case-opt c)) | |
192 | (not (lambda-case-kw c)) | |
1e2a8edb | 193 | (not (lambda-case-rest c))) |
3a88cb3b | 194 | (lp (lambda-case-alternate c))))))))) |
d97b69d9 | 195 | (hashq-set! labels gensym #f)) |
66d3e9a3 | 196 | (list gensym)) |
cf10678f | 197 | |
e5f5113c | 198 | ((<lexical-set> gensym exp) |
66d3e9a3 | 199 | (hashq-set! assigned gensym #t) |
d97b69d9 | 200 | (hashq-set! labels gensym #f) |
66d3e9a3 | 201 | (lset-adjoin eq? (step exp) gensym)) |
cf10678f | 202 | |
e5f5113c | 203 | ((<module-set> exp) |
cf10678f AW |
204 | (step exp)) |
205 | ||
e5f5113c | 206 | ((<toplevel-set> exp) |
cf10678f AW |
207 | (step exp)) |
208 | ||
e5f5113c | 209 | ((<toplevel-define> exp) |
cf10678f AW |
210 | (step exp)) |
211 | ||
212 | ((<sequence> exps) | |
d97b69d9 AW |
213 | (let lp ((exps exps) (ret '())) |
214 | (cond ((null? exps) '()) | |
215 | ((null? (cdr exps)) | |
216 | (lset-union eq? ret (step-tail (car exps)))) | |
217 | (else | |
218 | (lp (cdr exps) (lset-union eq? ret (step (car exps)))))))) | |
cf10678f | 219 | |
8a4ca0ea AW |
220 | ((<lambda> body) |
221 | ;; order is important here | |
222 | (hashq-set! bound-vars x '()) | |
223 | (let ((free (recur body x))) | |
224 | (hashq-set! bound-vars x (reverse! (hashq-ref bound-vars x))) | |
225 | (hashq-set! free-vars x free) | |
226 | free)) | |
227 | ||
3a88cb3b | 228 | ((<lambda-case> opt kw inits vars body alternate) |
8a4ca0ea AW |
229 | (hashq-set! bound-vars proc |
230 | (append (reverse vars) (hashq-ref bound-vars proc))) | |
231 | (lset-union | |
232 | eq? | |
233 | (lset-difference eq? | |
b0c8c187 AW |
234 | (lset-union eq? |
235 | (apply lset-union eq? (map step inits)) | |
8a4ca0ea AW |
236 | (step-tail body)) |
237 | vars) | |
3a88cb3b | 238 | (if alternate (step-tail alternate) '()))) |
66d3e9a3 | 239 | |
f4aa8d53 | 240 | ((<let> vars vals body) |
66d3e9a3 AW |
241 | (hashq-set! bound-vars proc |
242 | (append (reverse vars) (hashq-ref bound-vars proc))) | |
243 | (lset-difference eq? | |
d97b69d9 | 244 | (apply lset-union eq? (step-tail body) (map step vals)) |
66d3e9a3 | 245 | vars)) |
cf10678f | 246 | |
f4aa8d53 | 247 | ((<letrec> vars vals body) |
66d3e9a3 AW |
248 | (hashq-set! bound-vars proc |
249 | (append (reverse vars) (hashq-ref bound-vars proc))) | |
250 | (for-each (lambda (sym) (hashq-set! assigned sym #t)) vars) | |
251 | (lset-difference eq? | |
d97b69d9 | 252 | (apply lset-union eq? (step-tail body) (map step vals)) |
66d3e9a3 AW |
253 | vars)) |
254 | ||
c21c89b1 | 255 | ((<fix> vars vals body) |
d97b69d9 | 256 | ;; Try to allocate these procedures as labels. |
8a4ca0ea | 257 | (for-each (lambda (sym val) (hashq-set! labels sym val)) |
d97b69d9 | 258 | vars vals) |
c21c89b1 AW |
259 | (hashq-set! bound-vars proc |
260 | (append (reverse vars) (hashq-ref bound-vars proc))) | |
d97b69d9 AW |
261 | ;; Step into subexpressions. |
262 | (let* ((var-refs | |
263 | (map | |
264 | ;; Since we're trying to label-allocate the lambda, | |
265 | ;; pretend it's not a closure, and just recurse into its | |
266 | ;; body directly. (Otherwise, recursing on a closure | |
267 | ;; that references one of the fix's bound vars would | |
268 | ;; prevent label allocation.) | |
269 | (lambda (x) | |
270 | (record-case x | |
8a4ca0ea AW |
271 | ((<lambda> body) |
272 | ;; just like the closure case, except here we use | |
273 | ;; recur/labels instead of recur | |
274 | (hashq-set! bound-vars x '()) | |
275 | (let ((free (recur/labels body x vars))) | |
276 | (hashq-set! bound-vars x (reverse! (hashq-ref bound-vars x))) | |
277 | (hashq-set! free-vars x free) | |
278 | free)))) | |
d97b69d9 AW |
279 | vals)) |
280 | (vars-with-refs (map cons vars var-refs)) | |
281 | (body-refs (recur/labels body proc vars))) | |
282 | (define (delabel-dependents! sym) | |
283 | (let ((refs (assq-ref vars-with-refs sym))) | |
284 | (if refs | |
285 | (for-each (lambda (sym) | |
286 | (if (hashq-ref labels sym) | |
287 | (begin | |
288 | (hashq-set! labels sym #f) | |
289 | (delabel-dependents! sym)))) | |
290 | refs)))) | |
291 | ;; Stepping into the lambdas and the body might have made some | |
292 | ;; procedures not label-allocatable -- which might have | |
293 | ;; knock-on effects. For example: | |
294 | ;; (fix ((a (lambda () (b))) | |
295 | ;; (b (lambda () a))) | |
296 | ;; (a)) | |
297 | ;; As far as `a' is concerned, both `a' and `b' are | |
298 | ;; label-allocatable. But `b' references `a' not in a proc-tail | |
299 | ;; position, which makes `a' not label-allocatable. The | |
300 | ;; knock-on effect is that, when back-propagating this | |
301 | ;; information to `a', `b' will also become not | |
302 | ;; label-allocatable, as it is referenced within `a', which is | |
303 | ;; allocated as a closure. This is a transitive relationship. | |
304 | (for-each (lambda (sym) | |
305 | (if (not (hashq-ref labels sym)) | |
306 | (delabel-dependents! sym))) | |
307 | vars) | |
308 | ;; Now lift bound variables with label-allocated lambdas to the | |
309 | ;; parent procedure. | |
310 | (for-each | |
311 | (lambda (sym val) | |
312 | (if (hashq-ref labels sym) | |
313 | ;; Remove traces of the label-bound lambda. The free | |
314 | ;; vars will propagate up via the return val. | |
315 | (begin | |
316 | (hashq-set! bound-vars proc | |
317 | (append (hashq-ref bound-vars val) | |
318 | (hashq-ref bound-vars proc))) | |
319 | (hashq-remove! bound-vars val) | |
320 | (hashq-remove! free-vars val)))) | |
321 | vars vals) | |
322 | (lset-difference eq? | |
323 | (apply lset-union eq? body-refs var-refs) | |
324 | vars))) | |
c21c89b1 | 325 | |
8a4ca0ea AW |
326 | ((<let-values> exp body) |
327 | (lset-union eq? (step exp) (step body))) | |
66d3e9a3 AW |
328 | |
329 | (else '()))) | |
330 | ||
9059993f AW |
331 | ;; allocation: sym -> {lambda -> address} |
332 | ;; lambda -> (nlocs labels . free-locs) | |
333 | (define allocation (make-hash-table)) | |
334 | ||
66d3e9a3 AW |
335 | (define (allocate! x proc n) |
336 | (define (recur y) (allocate! y proc n)) | |
337 | (record-case x | |
338 | ((<application> proc args) | |
339 | (apply max (recur proc) (map recur args))) | |
cf10678f | 340 | |
66d3e9a3 AW |
341 | ((<conditional> test then else) |
342 | (max (recur test) (recur then) (recur else))) | |
cf10678f | 343 | |
e5f5113c | 344 | ((<lexical-set> exp) |
66d3e9a3 AW |
345 | (recur exp)) |
346 | ||
e5f5113c | 347 | ((<module-set> exp) |
66d3e9a3 AW |
348 | (recur exp)) |
349 | ||
e5f5113c | 350 | ((<toplevel-set> exp) |
66d3e9a3 AW |
351 | (recur exp)) |
352 | ||
e5f5113c | 353 | ((<toplevel-define> exp) |
66d3e9a3 AW |
354 | (recur exp)) |
355 | ||
356 | ((<sequence> exps) | |
357 | (apply max (map recur exps))) | |
358 | ||
8a4ca0ea | 359 | ((<lambda> body) |
66d3e9a3 AW |
360 | ;; allocate closure vars in order |
361 | (let lp ((c (hashq-ref free-vars x)) (n 0)) | |
362 | (if (pair? c) | |
363 | (begin | |
364 | (hashq-set! (hashq-ref allocation (car c)) | |
365 | x | |
366 | `(#f ,(hashq-ref assigned (car c)) . ,n)) | |
367 | (lp (cdr c) (1+ n))))) | |
368 | ||
8a4ca0ea | 369 | (let ((nlocs (allocate! body x 0)) |
66d3e9a3 AW |
370 | (free-addresses |
371 | (map (lambda (v) | |
372 | (hashq-ref (hashq-ref allocation v) proc)) | |
9059993f AW |
373 | (hashq-ref free-vars x))) |
374 | (labels (filter cdr | |
375 | (map (lambda (sym) | |
376 | (cons sym (hashq-ref labels sym))) | |
377 | (hashq-ref bound-vars x))))) | |
66d3e9a3 | 378 | ;; set procedure allocations |
8a4ca0ea | 379 | (hashq-set! allocation x (cons labels free-addresses))) |
66d3e9a3 | 380 | n) |
cf10678f | 381 | |
3a88cb3b | 382 | ((<lambda-case> opt kw inits vars body alternate) |
8a4ca0ea AW |
383 | (max |
384 | (let lp ((vars vars) (n n)) | |
385 | (if (null? vars) | |
b0c8c187 AW |
386 | (let ((nlocs (apply |
387 | max | |
b0c8c187 AW |
388 | (allocate! body proc n) |
389 | ;; inits not logically at the end, but they | |
390 | ;; are the list... | |
391 | (map (lambda (x) (allocate! x body n)) inits)))) | |
8a4ca0ea AW |
392 | ;; label and nlocs for the case |
393 | (hashq-set! allocation x (cons (gensym ":LCASE") nlocs)) | |
394 | nlocs) | |
395 | (begin | |
396 | (hashq-set! allocation (car vars) | |
397 | (make-hashq | |
398 | proc `(#t ,(hashq-ref assigned (car vars)) . ,n))) | |
399 | (lp (cdr vars) (1+ n))))) | |
3a88cb3b | 400 | (if alternate (allocate! alternate proc n) n))) |
8a4ca0ea | 401 | |
66d3e9a3 AW |
402 | ((<let> vars vals body) |
403 | (let ((nmax (apply max (map recur vals)))) | |
404 | (cond | |
405 | ;; the `or' hack | |
406 | ((and (conditional? body) | |
407 | (= (length vars) 1) | |
408 | (let ((v (car vars))) | |
409 | (and (not (hashq-ref assigned v)) | |
410 | (= (hashq-ref refcounts v 0) 2) | |
411 | (lexical-ref? (conditional-test body)) | |
412 | (eq? (lexical-ref-gensym (conditional-test body)) v) | |
413 | (lexical-ref? (conditional-then body)) | |
414 | (eq? (lexical-ref-gensym (conditional-then body)) v)))) | |
415 | (hashq-set! allocation (car vars) | |
416 | (make-hashq proc `(#t #f . ,n))) | |
417 | ;; the 1+ for this var | |
418 | (max nmax (1+ n) (allocate! (conditional-else body) proc n))) | |
419 | (else | |
420 | (let lp ((vars vars) (n n)) | |
421 | (if (null? vars) | |
422 | (max nmax (allocate! body proc n)) | |
423 | (let ((v (car vars))) | |
cf10678f AW |
424 | (hashq-set! |
425 | allocation v | |
66d3e9a3 AW |
426 | (make-hashq proc |
427 | `(#t ,(hashq-ref assigned v) . ,n))) | |
428 | (lp (cdr vars) (1+ n))))))))) | |
429 | ||
430 | ((<letrec> vars vals body) | |
431 | (let lp ((vars vars) (n n)) | |
432 | (if (null? vars) | |
433 | (let ((nmax (apply max | |
434 | (map (lambda (x) | |
435 | (allocate! x proc n)) | |
436 | vals)))) | |
437 | (max nmax (allocate! body proc n))) | |
438 | (let ((v (car vars))) | |
439 | (hashq-set! | |
440 | allocation v | |
441 | (make-hashq proc | |
442 | `(#t ,(hashq-ref assigned v) . ,n))) | |
443 | (lp (cdr vars) (1+ n)))))) | |
cf10678f | 444 | |
c21c89b1 | 445 | ((<fix> vars vals body) |
d97b69d9 AW |
446 | (let lp ((in vars) (n n)) |
447 | (if (null? in) | |
448 | (let lp ((vars vars) (vals vals) (nmax n)) | |
449 | (cond | |
450 | ((null? vars) | |
451 | (max nmax (allocate! body proc n))) | |
452 | ((hashq-ref labels (car vars)) | |
8a4ca0ea | 453 | ;; allocate lambda body inline to proc |
d97b69d9 AW |
454 | (lp (cdr vars) |
455 | (cdr vals) | |
456 | (record-case (car vals) | |
8a4ca0ea AW |
457 | ((<lambda> body) |
458 | (max nmax (allocate! body proc n)))))) | |
d97b69d9 AW |
459 | (else |
460 | ;; allocate closure | |
461 | (lp (cdr vars) | |
462 | (cdr vals) | |
463 | (max nmax (allocate! (car vals) proc n)))))) | |
464 | ||
465 | (let ((v (car in))) | |
466 | (cond | |
467 | ((hashq-ref assigned v) | |
468 | (error "fixpoint procedures may not be assigned" x)) | |
469 | ((hashq-ref labels v) | |
470 | ;; no binding, it's a label | |
471 | (lp (cdr in) n)) | |
472 | (else | |
473 | ;; allocate closure binding | |
474 | (hashq-set! allocation v (make-hashq proc `(#t #f . ,n))) | |
475 | (lp (cdr in) (1+ n)))))))) | |
c21c89b1 | 476 | |
8a4ca0ea AW |
477 | ((<let-values> exp body) |
478 | (max (recur exp) (recur body))) | |
66d3e9a3 AW |
479 | |
480 | (else n))) | |
cf10678f | 481 | |
d97b69d9 | 482 | (analyze! x #f '() #t #f) |
66d3e9a3 | 483 | (allocate! x #f 0) |
cf10678f AW |
484 | |
485 | allocation) | |
4b856371 LC |
486 | |
487 | \f | |
48b1db75 LC |
488 | ;;; |
489 | ;;; Tree analyses for warnings. | |
490 | ;;; | |
491 | ||
492 | (define-record-type <tree-analysis> | |
493 | (make-tree-analysis leaf down up post init) | |
494 | tree-analysis? | |
495 | (leaf tree-analysis-leaf) ;; (lambda (x result env) ...) | |
496 | (down tree-analysis-down) ;; (lambda (x result env) ...) | |
497 | (up tree-analysis-up) ;; (lambda (x result env) ...) | |
498 | (post tree-analysis-post) ;; (lambda (result env) ...) | |
499 | (init tree-analysis-init)) ;; arbitrary value | |
500 | ||
501 | (define (analyze-tree analyses tree env) | |
502 | "Run all tree analyses listed in ANALYSES on TREE for ENV, using | |
503 | `tree-il-fold'. Return TREE." | |
504 | (define (traverse proc) | |
505 | (lambda (x results) | |
506 | (map (lambda (analysis result) | |
507 | ((proc analysis) x result env)) | |
508 | analyses | |
509 | results))) | |
510 | ||
511 | (let ((results | |
512 | (tree-il-fold (traverse tree-analysis-leaf) | |
513 | (traverse tree-analysis-down) | |
514 | (traverse tree-analysis-up) | |
515 | (map tree-analysis-init analyses) | |
516 | tree))) | |
517 | ||
518 | (for-each (lambda (analysis result) | |
519 | ((tree-analysis-post analysis) result env)) | |
520 | analyses | |
521 | results)) | |
522 | ||
523 | tree) | |
524 | ||
525 | \f | |
4b856371 LC |
526 | ;;; |
527 | ;;; Unused variable analysis. | |
528 | ;;; | |
529 | ||
530 | ;; <binding-info> records are used during tree traversals in | |
531 | ;; `report-unused-variables'. They contain a list of the local vars | |
532 | ;; currently in scope, a list of locals vars that have been referenced, and a | |
533 | ;; "location stack" (the stack of `tree-il-src' values for each parent tree). | |
534 | (define-record-type <binding-info> | |
535 | (make-binding-info vars refs locs) | |
536 | binding-info? | |
537 | (vars binding-info-vars) ;; ((GENSYM NAME LOCATION) ...) | |
538 | (refs binding-info-refs) ;; (GENSYM ...) | |
539 | (locs binding-info-locs)) ;; (LOCATION ...) | |
540 | ||
48b1db75 | 541 | (define unused-variable-analysis |
ae03cf1f | 542 | ;; Report unused variables in the given tree. |
48b1db75 LC |
543 | (make-tree-analysis |
544 | (lambda (x info env) | |
545 | ;; X is a leaf: extend INFO's refs accordingly. | |
546 | (let ((refs (binding-info-refs info)) | |
547 | (vars (binding-info-vars info)) | |
548 | (locs (binding-info-locs info))) | |
549 | (record-case x | |
550 | ((<lexical-ref> gensym) | |
551 | (make-binding-info vars (cons gensym refs) locs)) | |
552 | (else info)))) | |
553 | ||
554 | (lambda (x info env) | |
555 | ;; Going down into X: extend INFO's variable list | |
556 | ;; accordingly. | |
557 | (let ((refs (binding-info-refs info)) | |
558 | (vars (binding-info-vars info)) | |
559 | (locs (binding-info-locs info)) | |
560 | (src (tree-il-src x))) | |
561 | (define (extend inner-vars inner-names) | |
562 | (append (map (lambda (var name) | |
563 | (list var name src)) | |
564 | inner-vars | |
565 | inner-names) | |
566 | vars)) | |
567 | (record-case x | |
568 | ((<lexical-set> gensym) | |
569 | (make-binding-info vars (cons gensym refs) | |
570 | (cons src locs))) | |
571 | ((<lambda-case> req opt inits rest kw vars) | |
48b1db75 | 572 | (let ((names `(,@req |
632e7c32 | 573 | ,@(or opt '()) |
48b1db75 LC |
574 | ,@(if rest (list rest) '()) |
575 | ,@(if kw (map cadr (cdr kw)) '())))) | |
576 | (make-binding-info (extend vars names) refs | |
577 | (cons src locs)))) | |
578 | ((<let> vars names) | |
579 | (make-binding-info (extend vars names) refs | |
580 | (cons src locs))) | |
581 | ((<letrec> vars names) | |
582 | (make-binding-info (extend vars names) refs | |
583 | (cons src locs))) | |
584 | ((<fix> vars names) | |
585 | (make-binding-info (extend vars names) refs | |
586 | (cons src locs))) | |
587 | (else info)))) | |
588 | ||
589 | (lambda (x info env) | |
590 | ;; Leaving X's scope: shrink INFO's variable list | |
591 | ;; accordingly and reported unused nested variables. | |
592 | (let ((refs (binding-info-refs info)) | |
593 | (vars (binding-info-vars info)) | |
594 | (locs (binding-info-locs info))) | |
595 | (define (shrink inner-vars refs) | |
596 | (for-each (lambda (var) | |
597 | (let ((gensym (car var))) | |
598 | ;; Don't report lambda parameters as | |
599 | ;; unused. | |
600 | (if (and (not (memq gensym refs)) | |
601 | (not (and (lambda-case? x) | |
602 | (memq gensym | |
603 | inner-vars)))) | |
604 | (let ((name (cadr var)) | |
605 | ;; We can get approximate | |
606 | ;; source location by going up | |
607 | ;; the LOCS location stack. | |
608 | (loc (or (caddr var) | |
609 | (find pair? locs)))) | |
610 | (warning 'unused-variable loc name))))) | |
611 | (filter (lambda (var) | |
612 | (memq (car var) inner-vars)) | |
613 | vars)) | |
614 | (fold alist-delete vars inner-vars)) | |
615 | ||
616 | ;; For simplicity, we leave REFS untouched, i.e., with | |
617 | ;; names of variables that are now going out of scope. | |
618 | ;; It doesn't hurt as these are unique names, it just | |
619 | ;; makes REFS unnecessarily fat. | |
620 | (record-case x | |
621 | ((<lambda-case> vars) | |
622 | (make-binding-info (shrink vars refs) refs | |
623 | (cdr locs))) | |
624 | ((<let> vars) | |
625 | (make-binding-info (shrink vars refs) refs | |
626 | (cdr locs))) | |
627 | ((<letrec> vars) | |
628 | (make-binding-info (shrink vars refs) refs | |
629 | (cdr locs))) | |
630 | ((<fix> vars) | |
631 | (make-binding-info (shrink vars refs) refs | |
632 | (cdr locs))) | |
633 | (else info)))) | |
634 | ||
635 | (lambda (result env) #t) | |
636 | (make-binding-info '() '() '()))) | |
f67ddf9d LC |
637 | |
638 | \f | |
639 | ;;; | |
640 | ;;; Unbound variable analysis. | |
641 | ;;; | |
642 | ||
643 | ;; <toplevel-info> records are used during tree traversal in search of | |
644 | ;; possibly unbound variable. They contain a list of references to | |
645 | ;; potentially unbound top-level variables, a list of the top-level defines | |
646 | ;; that have been encountered, and a "location stack" (see above). | |
647 | (define-record-type <toplevel-info> | |
648 | (make-toplevel-info refs defs locs) | |
649 | toplevel-info? | |
650 | (refs toplevel-info-refs) ;; ((VARIABLE-NAME . LOCATION) ...) | |
651 | (defs toplevel-info-defs) ;; (VARIABLE-NAME ...) | |
652 | (locs toplevel-info-locs)) ;; (LOCATION ...) | |
653 | ||
6bb891dc | 654 | (define (goops-toplevel-definition proc args env) |
b6d2306d LC |
655 | ;; If application of PROC to ARGS is a GOOPS top-level definition, return |
656 | ;; the name of the variable being defined; otherwise return #f. This | |
657 | ;; assumes knowledge of the current implementation of `define-class' et al. | |
6bb891dc LC |
658 | (define (toplevel-define-arg args) |
659 | (and (pair? args) (pair? (cdr args)) (null? (cddr args)) | |
660 | (record-case (car args) | |
661 | ((<const> exp) | |
662 | (and (symbol? exp) exp)) | |
663 | (else #f)))) | |
664 | ||
b6d2306d LC |
665 | (record-case proc |
666 | ((<module-ref> mod public? name) | |
667 | (and (equal? mod '(oop goops)) | |
668 | (not public?) | |
669 | (eq? name 'toplevel-define!) | |
6bb891dc LC |
670 | (toplevel-define-arg args))) |
671 | ((<toplevel-ref> name) | |
672 | ;; This may be the result of expanding one of the GOOPS macros within | |
673 | ;; `oop/goops.scm'. | |
674 | (and (eq? name 'toplevel-define!) | |
675 | (eq? env (resolve-module '(oop goops))) | |
676 | (toplevel-define-arg args))) | |
b6d2306d LC |
677 | (else #f))) |
678 | ||
48b1db75 | 679 | (define unbound-variable-analysis |
ae03cf1f | 680 | ;; Report possibly unbound variables in the given tree. |
48b1db75 LC |
681 | (make-tree-analysis |
682 | (lambda (x info env) | |
683 | ;; X is a leaf: extend INFO's refs accordingly. | |
684 | (let ((refs (toplevel-info-refs info)) | |
685 | (defs (toplevel-info-defs info)) | |
686 | (locs (toplevel-info-locs info))) | |
687 | (define (bound? name) | |
688 | (or (and (module? env) | |
689 | (module-variable env name)) | |
690 | (memq name defs))) | |
691 | ||
692 | (record-case x | |
693 | ((<toplevel-ref> name src) | |
694 | (if (bound? name) | |
695 | info | |
696 | (let ((src (or src (find pair? locs)))) | |
697 | (make-toplevel-info (alist-cons name src refs) | |
698 | defs | |
699 | locs)))) | |
700 | (else info)))) | |
701 | ||
702 | (lambda (x info env) | |
703 | ;; Going down into X. | |
704 | (let* ((refs (toplevel-info-refs info)) | |
705 | (defs (toplevel-info-defs info)) | |
706 | (src (tree-il-src x)) | |
707 | (locs (cons src (toplevel-info-locs info)))) | |
708 | (define (bound? name) | |
709 | (or (and (module? env) | |
710 | (module-variable env name)) | |
711 | (memq name defs))) | |
712 | ||
713 | (record-case x | |
714 | ((<toplevel-set> name src) | |
715 | (if (bound? name) | |
716 | (make-toplevel-info refs defs locs) | |
717 | (let ((src (find pair? locs))) | |
718 | (make-toplevel-info (alist-cons name src refs) | |
719 | defs | |
720 | locs)))) | |
721 | ((<toplevel-define> name) | |
722 | (make-toplevel-info (alist-delete name refs eq?) | |
723 | (cons name defs) | |
724 | locs)) | |
725 | ||
726 | ((<application> proc args) | |
727 | ;; Check for a dynamic top-level definition, as is | |
728 | ;; done by code expanded from GOOPS macros. | |
729 | (let ((name (goops-toplevel-definition proc args | |
730 | env))) | |
731 | (if (symbol? name) | |
732 | (make-toplevel-info (alist-delete name refs | |
733 | eq?) | |
734 | (cons name defs) | |
735 | locs) | |
736 | (make-toplevel-info refs defs locs)))) | |
737 | (else | |
738 | (make-toplevel-info refs defs locs))))) | |
739 | ||
740 | (lambda (x info env) | |
741 | ;; Leaving X's scope. | |
742 | (let ((refs (toplevel-info-refs info)) | |
743 | (defs (toplevel-info-defs info)) | |
744 | (locs (toplevel-info-locs info))) | |
745 | (make-toplevel-info refs defs (cdr locs)))) | |
746 | ||
747 | (lambda (toplevel env) | |
748 | ;; Post-process the result. | |
749 | (for-each (lambda (name+loc) | |
750 | (let ((name (car name+loc)) | |
751 | (loc (cdr name+loc))) | |
752 | (warning 'unbound-variable loc name))) | |
753 | (reverse (toplevel-info-refs toplevel)))) | |
754 | ||
755 | (make-toplevel-info '() '() '()))) | |
ae03cf1f LC |
756 | |
757 | \f | |
758 | ;;; | |
759 | ;;; Arity analysis. | |
760 | ;;; | |
761 | ||
af5ed549 | 762 | ;; <arity-info> records contain information about lexical definitions of |
ae03cf1f LC |
763 | ;; procedures currently in scope, top-level procedure definitions that have |
764 | ;; been encountered, and calls to top-level procedures that have been | |
765 | ;; encountered. | |
766 | (define-record-type <arity-info> | |
767 | (make-arity-info toplevel-calls lexical-lambdas toplevel-lambdas) | |
768 | arity-info? | |
769 | (toplevel-calls toplevel-procedure-calls) ;; ((NAME . APPLICATION) ...) | |
770 | (lexical-lambdas lexical-lambdas) ;; ((GENSYM . DEFINITION) ...) | |
771 | (toplevel-lambdas toplevel-lambdas)) ;; ((NAME . DEFINITION) ...) | |
772 | ||
773 | (define (validate-arity proc application lexical?) | |
774 | ;; Validate the argument count of APPLICATION, a tree-il application of | |
775 | ;; PROC, emitting a warning in case of argument count mismatch. | |
776 | ||
af5ed549 LC |
777 | (define (filter-keyword-args keywords allow-other-keys? args) |
778 | ;; Filter keyword arguments from ARGS and return the resulting list. | |
779 | ;; KEYWORDS is the list of allowed keywords, and ALLOW-OTHER-KEYS? | |
780 | ;; specified whethere keywords not listed in KEYWORDS are allowed. | |
781 | (let loop ((args args) | |
782 | (result '())) | |
783 | (if (null? args) | |
784 | (reverse result) | |
785 | (let ((arg (car args))) | |
786 | (if (and (const? arg) | |
787 | (or (memq (const-exp arg) keywords) | |
788 | (and allow-other-keys? | |
789 | (keyword? (const-exp arg))))) | |
790 | (loop (if (pair? (cdr args)) | |
791 | (cddr args) | |
792 | '()) | |
793 | result) | |
794 | (loop (cdr args) | |
795 | (cons arg result))))))) | |
796 | ||
99480e11 LC |
797 | (define (arities proc) |
798 | ;; Return the arities of PROC, which can be either a tree-il or a | |
ae03cf1f LC |
799 | ;; procedure. |
800 | (define (len x) | |
801 | (or (and (or (null? x) (pair? x)) | |
802 | (length x)) | |
803 | 0)) | |
af5ed549 | 804 | (cond ((program? proc) |
99480e11 LC |
805 | (values (program-name proc) |
806 | (map (lambda (a) | |
807 | (list (arity:nreq a) (arity:nopt a) (arity:rest? a) | |
808 | (map car (arity:kw a)) | |
809 | (arity:allow-other-keys? a))) | |
810 | (program-arities proc)))) | |
ae03cf1f LC |
811 | ((procedure? proc) |
812 | (let ((arity (procedure-property proc 'arity))) | |
813 | (values (procedure-name proc) | |
99480e11 LC |
814 | (list (list (car arity) (cadr arity) (caddr arity) |
815 | #f #f))))) | |
ae03cf1f | 816 | (else |
99480e11 LC |
817 | (let loop ((name #f) |
818 | (proc proc) | |
819 | (arities '())) | |
820 | (if (not proc) | |
821 | (values name (reverse arities)) | |
822 | (record-case proc | |
3a88cb3b AW |
823 | ((<lambda-case> req opt rest kw alternate) |
824 | (loop name alternate | |
99480e11 LC |
825 | (cons (list (len req) (len opt) rest |
826 | (and (pair? kw) (map car (cdr kw))) | |
827 | (and (pair? kw) (car kw))) | |
828 | arities))) | |
829 | ((<lambda> meta body) | |
830 | (loop (assoc-ref meta 'name) body arities)) | |
831 | (else | |
832 | (values #f #f)))))))) | |
ae03cf1f LC |
833 | |
834 | (let ((args (application-args application)) | |
835 | (src (tree-il-src application))) | |
99480e11 LC |
836 | (call-with-values (lambda () (arities proc)) |
837 | (lambda (name arities) | |
838 | (define matches? | |
839 | (find (lambda (arity) | |
840 | (pmatch arity | |
841 | ((,req ,opt ,rest? ,kw ,aok?) | |
842 | (let ((args (if (pair? kw) | |
843 | (filter-keyword-args kw aok? args) | |
844 | args))) | |
845 | (if (and req opt) | |
846 | (let ((count (length args))) | |
847 | (and (>= count req) | |
848 | (or rest? | |
849 | (<= count (+ req opt))))) | |
850 | #t))) | |
851 | (else #t))) | |
852 | arities)) | |
853 | ||
854 | (if (not matches?) | |
855 | (warning 'arity-mismatch src | |
856 | (or name (with-output-to-string (lambda () (write proc)))) | |
857 | lexical?))))) | |
ae03cf1f LC |
858 | #t) |
859 | ||
860 | (define arity-analysis | |
861 | ;; Report arity mismatches in the given tree. | |
862 | (make-tree-analysis | |
863 | (lambda (x info env) | |
864 | ;; X is a leaf. | |
865 | info) | |
866 | (lambda (x info env) | |
867 | ;; Down into X. | |
868 | (define (extend lexical-name val info) | |
869 | ;; If VAL is a lambda, add NAME to the lexical-lambdas of INFO. | |
870 | (let ((toplevel-calls (toplevel-procedure-calls info)) | |
871 | (lexical-lambdas (lexical-lambdas info)) | |
872 | (toplevel-lambdas (toplevel-lambdas info))) | |
873 | (record-case val | |
874 | ((<lambda> body) | |
875 | (make-arity-info toplevel-calls | |
876 | (alist-cons lexical-name val | |
877 | lexical-lambdas) | |
878 | toplevel-lambdas)) | |
879 | ((<lexical-ref> gensym) | |
880 | ;; lexical alias | |
881 | (let ((val* (assq gensym lexical-lambdas))) | |
882 | (if (pair? val*) | |
883 | (extend lexical-name (cdr val*) info) | |
884 | info))) | |
885 | ((<toplevel-ref> name) | |
886 | ;; top-level alias | |
887 | (make-arity-info toplevel-calls | |
888 | (alist-cons lexical-name val | |
889 | lexical-lambdas) | |
890 | toplevel-lambdas)) | |
891 | (else info)))) | |
892 | ||
893 | (let ((toplevel-calls (toplevel-procedure-calls info)) | |
894 | (lexical-lambdas (lexical-lambdas info)) | |
895 | (toplevel-lambdas (toplevel-lambdas info))) | |
896 | ||
897 | (record-case x | |
898 | ((<toplevel-define> name exp) | |
899 | (record-case exp | |
900 | ((<lambda> body) | |
901 | (make-arity-info toplevel-calls | |
902 | lexical-lambdas | |
903 | (alist-cons name exp toplevel-lambdas))) | |
904 | ((<toplevel-ref> name) | |
905 | ;; alias for another toplevel | |
906 | (let ((proc (assq name toplevel-lambdas))) | |
907 | (make-arity-info toplevel-calls | |
908 | lexical-lambdas | |
909 | (alist-cons (toplevel-define-name x) | |
910 | (if (pair? proc) | |
911 | (cdr proc) | |
912 | exp) | |
913 | toplevel-lambdas)))) | |
914 | (else info))) | |
915 | ((<let> vars vals) | |
916 | (fold extend info vars vals)) | |
917 | ((<letrec> vars vals) | |
918 | (fold extend info vars vals)) | |
919 | ((<fix> vars vals) | |
920 | (fold extend info vars vals)) | |
921 | ||
922 | ((<application> proc args src) | |
923 | (record-case proc | |
924 | ((<lambda> body) | |
925 | (validate-arity proc x #t) | |
926 | info) | |
927 | ((<toplevel-ref> name) | |
928 | (make-arity-info (alist-cons name x toplevel-calls) | |
929 | lexical-lambdas | |
930 | toplevel-lambdas)) | |
931 | ((<lexical-ref> gensym) | |
932 | (let ((proc (assq gensym lexical-lambdas))) | |
933 | (if (pair? proc) | |
934 | (record-case (cdr proc) | |
935 | ((<toplevel-ref> name) | |
936 | ;; alias to toplevel | |
937 | (make-arity-info (alist-cons name x toplevel-calls) | |
938 | lexical-lambdas | |
939 | toplevel-lambdas)) | |
940 | (else | |
941 | (validate-arity (cdr proc) x #t) | |
942 | info)) | |
943 | ||
944 | ;; If GENSYM wasn't found, it may be because it's an | |
945 | ;; argument of the procedure being compiled. | |
946 | info))) | |
947 | (else info))) | |
948 | (else info)))) | |
949 | ||
950 | (lambda (x info env) | |
951 | ;; Up from X. | |
952 | (define (shrink name val info) | |
953 | ;; Remove NAME from the lexical-lambdas of INFO. | |
954 | (let ((toplevel-calls (toplevel-procedure-calls info)) | |
955 | (lexical-lambdas (lexical-lambdas info)) | |
956 | (toplevel-lambdas (toplevel-lambdas info))) | |
957 | (make-arity-info toplevel-calls | |
958 | (alist-delete name lexical-lambdas eq?) | |
959 | toplevel-lambdas))) | |
960 | ||
961 | (let ((toplevel-calls (toplevel-procedure-calls info)) | |
962 | (lexical-lambdas (lexical-lambdas info)) | |
963 | (toplevel-lambdas (toplevel-lambdas info))) | |
964 | (record-case x | |
965 | ((<let> vars vals) | |
966 | (fold shrink info vars vals)) | |
967 | ((<letrec> vars vals) | |
968 | (fold shrink info vars vals)) | |
969 | ((<fix> vars vals) | |
970 | (fold shrink info vars vals)) | |
971 | ||
972 | (else info)))) | |
973 | ||
974 | (lambda (result env) | |
975 | ;; Post-processing: check all top-level procedure calls that have been | |
976 | ;; encountered. | |
977 | (let ((toplevel-calls (toplevel-procedure-calls result)) | |
978 | (toplevel-lambdas (toplevel-lambdas result))) | |
979 | (for-each (lambda (name+application) | |
980 | (let* ((name (car name+application)) | |
981 | (application (cdr name+application)) | |
982 | (proc | |
983 | (or (assoc-ref toplevel-lambdas name) | |
984 | (and (module? env) | |
985 | (false-if-exception | |
986 | (module-ref env name))))) | |
987 | (proc* | |
988 | ;; handle toplevel aliases | |
989 | (if (toplevel-ref? proc) | |
990 | (let ((name (toplevel-ref-name proc))) | |
991 | (and (module? env) | |
992 | (false-if-exception | |
993 | (module-ref env name)))) | |
994 | proc))) | |
995 | ;; (format #t "toplevel-call to ~A (~A) from ~A~%" | |
996 | ;; name proc* application) | |
997 | (if (or (lambda? proc*) (procedure? proc*)) | |
998 | (validate-arity proc* application (lambda? proc*))))) | |
999 | toplevel-calls))) | |
1000 | ||
1001 | (make-arity-info '() '() '()))) |