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1 | /* | |
2 | ** Splint - annotation-assisted static program checker | |
3 | ** Copyright (C) 1994-2002 University of Virginia, | |
4 | ** Massachusetts Institute of Technology | |
5 | ** | |
6 | ** This program is free software; you can redistribute it and/or modify it | |
7 | ** under the terms of the GNU General Public License as published by the | |
8 | ** Free Software Foundation; either version 2 of the License, or (at your | |
9 | ** option) any later version. | |
10 | ** | |
11 | ** This program is distributed in the hope that it will be useful, but | |
12 | ** WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | ** General Public License for more details. | |
15 | ** | |
16 | ** The GNU General Public License is available from http://www.gnu.org/ or | |
17 | ** the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
18 | ** MA 02111-1307, USA. | |
19 | ** | |
20 | ** For information on splint: info@splint.org | |
21 | ** To report a bug: splint-bug@splint.org | |
22 | ** For more information: http://www.splint.org | |
23 | */ | |
24 | ||
25 | /* | |
26 | ** loopHeuristics.c | |
27 | */ | |
28 | ||
29 | /*This file was formerly called forjunk.c C | |
30 | renamed Oct 8, 2001 - DRL | |
31 | */ | |
32 | ||
33 | /* #define DEBUGPRINT 1 */ | |
34 | ||
35 | # include <ctype.h> /* for isdigit */ | |
36 | # include "splintMacros.nf" | |
37 | # include "basic.h" | |
38 | # include "cgrammar.h" | |
39 | # include "cgrammar_tokens.h" | |
40 | ||
41 | # include "exprChecks.h" | |
42 | # include "exprNodeSList.h" | |
43 | ||
44 | /*@access constraint, exprNode @*/ /* !!! NO! */ | |
45 | ||
46 | /*@access constraintExpr @*/ /* !!! NO! */ | |
47 | ||
48 | /*@-nullderef@*/ /* !!! DRL needs to fix this code! */ | |
49 | /*@-nullstate@*/ /* !!! DRL needs to fix this code! */ | |
50 | /*@-nullpass@*/ /* !!! DRL needs to fix this code! */ | |
51 | /*@-temptrans@*/ /* !!! DRL needs to fix this code! */ | |
52 | ||
53 | static bool isInc (/*@observer@*/ constraintExpr c) /*@*/ | |
54 | { | |
55 | ||
56 | llassert (constraintExpr_isDefined (c) ); | |
57 | if (c->kind == binaryexpr ) | |
58 | { | |
59 | constraintExprBinaryOpKind binOP; | |
60 | constraintExpr t1, t2; | |
61 | t1 = constraintExprData_binaryExprGetExpr1 (c->data); | |
62 | t2 = constraintExprData_binaryExprGetExpr2 (c->data); | |
63 | ||
64 | binOP = constraintExprData_binaryExprGetOp (c->data); | |
65 | if (binOP == BINARYOP_PLUS) | |
66 | if (constraintExpr_isLit (t2) && constraintExpr_getValue (t2) == 1 ) | |
67 | { | |
68 | return TRUE; | |
69 | } | |
70 | } | |
71 | ||
72 | return FALSE; | |
73 | } | |
74 | ||
75 | /* look for constraints like cexrp = cexrp + 1 */ | |
76 | static bool incVar (/*@notnull@*/ constraint c) /*@*/ | |
77 | { | |
78 | constraintExpr t1; | |
79 | if (c->ar != EQ) | |
80 | { | |
81 | return FALSE; | |
82 | } | |
83 | if (! isInc (c->expr ) ) | |
84 | return FALSE; | |
85 | ||
86 | llassert (constraintExpr_isDefined (c->expr) ); | |
87 | llassert (c->expr->kind == binaryexpr); | |
88 | ||
89 | t1 = constraintExprData_binaryExprGetExpr1 (c->expr->data); | |
90 | if (constraintExpr_similar (c->lexpr, t1) ) | |
91 | return TRUE; | |
92 | ||
93 | return FALSE; | |
94 | } | |
95 | /*@noaccess constraintExpr @*/ | |
96 | ||
97 | ||
98 | static bool increments (/*@observer@*/ constraint c, | |
99 | /*@observer@*/ constraintExpr var) | |
100 | { | |
101 | llassert (constraint_isDefined (c) ); | |
102 | ||
103 | if (constraint_isUndefined (c) ) | |
104 | { | |
105 | return FALSE; | |
106 | } | |
107 | ||
108 | llassert (incVar (c)); | |
109 | if (constraintExpr_similar (c->lexpr, var) ) | |
110 | return TRUE; | |
111 | else | |
112 | return FALSE; | |
113 | } | |
114 | ||
115 | static bool canGetForTimes (/*@notnull@*/ exprNode forPred, /*@notnull@*/ exprNode forBody) | |
116 | { | |
117 | ||
118 | exprNode init, test, inc, t1, t2; | |
119 | lltok tok; | |
120 | ||
121 | llassert (exprNode_isDefined (forPred) ); | |
122 | llassert (exprNode_isDefined (forBody) ); | |
123 | ||
124 | init = exprData_getTripleInit (forPred->edata); | |
125 | test = exprData_getTripleTest (forPred->edata); | |
126 | inc = exprData_getTripleInc (forPred->edata); | |
127 | ||
128 | llassert (exprNode_isDefined (test) ); | |
129 | ||
130 | if (exprNode_isUndefined (test) ) | |
131 | { | |
132 | return FALSE; | |
133 | } | |
134 | ||
135 | llassert (exprNode_isDefined (inc) ); | |
136 | ||
137 | if (exprNode_isUndefined (inc) ) | |
138 | { | |
139 | return FALSE; | |
140 | } | |
141 | ||
142 | if (test->kind != XPR_PREOP) | |
143 | return FALSE; | |
144 | ||
145 | tok = (exprData_getUopTok (test->edata)); | |
146 | if (!lltok_isMult (tok) ) | |
147 | { | |
148 | return FALSE; | |
149 | } | |
150 | ||
151 | /* should check preop too */ | |
152 | if (inc->kind != XPR_POSTOP) | |
153 | { | |
154 | return FALSE; | |
155 | } | |
156 | ||
157 | tok = (exprData_getUopTok (inc->edata)); | |
158 | if (lltok_isIncOp (tok) ) | |
159 | { | |
160 | t1 = exprData_getUopNode (test->edata); | |
161 | t2 = exprData_getUopNode (inc->edata); | |
162 | llassert (exprNode_isDefined (t2) && exprNode_isDefined (t2) ); | |
163 | ||
164 | if (exprNode_isUndefined (t1) || exprNode_isUndefined (t2) ) | |
165 | { | |
166 | return FALSE; | |
167 | } | |
168 | ||
169 | if (sRef_sameName (t1->sref, t2->sref) ) | |
170 | { | |
171 | return TRUE; | |
172 | } | |
173 | } | |
174 | return FALSE; | |
175 | } | |
176 | ||
177 | static /*@only@*/ constraintList getLessThanConstraints (/*@observer@*/ constraintList c) | |
178 | { | |
179 | constraintList ret; | |
180 | ||
181 | ret = constraintList_makeNew (); | |
182 | constraintList_elements (c, el) | |
183 | { | |
184 | llassert (constraint_isDefined (el)); | |
185 | if ( constraint_isUndefined (el) ) | |
186 | continue; | |
187 | ||
188 | if (el->ar == LT || el->ar == LTE) | |
189 | { | |
190 | constraint temp; | |
191 | temp = constraint_copy (el); | |
192 | ||
193 | ret = constraintList_add (ret, temp); | |
194 | } | |
195 | } | |
196 | end_constraintList_elements; | |
197 | ||
198 | return ret; | |
199 | } | |
200 | ||
201 | static /*@only@*/ constraintList getIncConstraints (/*@observer@*/ constraintList c) | |
202 | { | |
203 | constraintList ret; | |
204 | ||
205 | ret = constraintList_makeNew (); | |
206 | constraintList_elements (c, el) | |
207 | { | |
208 | llassert (constraint_isDefined (el)); | |
209 | ||
210 | if (incVar (el) ) | |
211 | { | |
212 | constraint temp; | |
213 | temp = constraint_copy (el); | |
214 | ret = constraintList_add (ret, temp); | |
215 | } | |
216 | } | |
217 | end_constraintList_elements; | |
218 | ||
219 | return ret; | |
220 | } | |
221 | ||
222 | static /*@only@*/ constraintExpr getForTimes (/*@notnull@*/ exprNode forPred, /*@notnull@*/ exprNode forBody) | |
223 | { | |
224 | ||
225 | exprNode init, test, inc, t1, t2; | |
226 | constraintList ltCon; | |
227 | constraintList incCon; | |
228 | constraintExpr ret; | |
229 | ||
230 | lltok tok; | |
231 | ||
232 | init = exprData_getTripleInit (forPred->edata); | |
233 | test = exprData_getTripleTest (forPred->edata); | |
234 | inc = exprData_getTripleInc (forPred->edata); | |
235 | ||
236 | llassert (exprNode_isDefined (test) ); | |
237 | llassert (exprNode_isDefined (inc) ); | |
238 | ||
239 | ltCon = getLessThanConstraints (test->trueEnsuresConstraints); | |
240 | incCon = getIncConstraints (inc->ensuresConstraints); | |
241 | ||
242 | DPRINTF (( message ("getForTimes: ltCon: %s from %s", constraintList_print (ltCon), constraintList_print (test->trueEnsuresConstraints) ) )); | |
243 | ||
244 | DPRINTF (( message ("getForTimes: incCon: %s from %s", constraintList_print (incCon), constraintList_print (inc->ensuresConstraints) ) )); | |
245 | ||
246 | constraintList_elements (ltCon, el) | |
247 | { | |
248 | constraintList_elements (incCon, el2) | |
249 | { | |
250 | if ( increments (el2, el->lexpr) ) | |
251 | { | |
252 | DPRINTF (( message ("getForTimes: %s increments %s", constraint_print (el2), constraint_print (el) ) )); | |
253 | ret = constraintExpr_copy (el->expr); | |
254 | constraintList_free (ltCon); | |
255 | constraintList_free (incCon); | |
256 | return ret; | |
257 | ||
258 | } | |
259 | else | |
260 | { | |
261 | ; | |
262 | DPRINTF (( message ("getForTimes: %s doesn't increment %s", constraint_print (el2), constraint_print (el) ) )); | |
263 | } | |
264 | } | |
265 | end_constraintList_elements; | |
266 | } | |
267 | ||
268 | end_constraintList_elements; | |
269 | ||
270 | constraintList_free (ltCon); | |
271 | constraintList_free (incCon); | |
272 | ||
273 | DPRINTF (( message ("getForTimes: %s %s resorting to ugly hack", exprNode_unparse (forPred), exprNode_unparse (forBody) ) )); | |
274 | if (! canGetForTimes (forPred, forBody) ) | |
275 | { | |
276 | return NULL; | |
277 | } | |
278 | ||
279 | ||
280 | if (test->kind != XPR_PREOP) | |
281 | llassert (FALSE); | |
282 | ||
283 | tok = (exprData_getUopTok (test->edata)); | |
284 | if (!lltok_isMult (tok) ) | |
285 | { | |
286 | llassert ( FALSE ); | |
287 | } | |
288 | ||
289 | /* should check preop too */ | |
290 | if (inc->kind != XPR_POSTOP) | |
291 | { | |
292 | llassert (FALSE ); | |
293 | } | |
294 | ||
295 | tok = (exprData_getUopTok (inc->edata)); | |
296 | if (lltok_isIncOp (tok) ) | |
297 | { | |
298 | t1 = exprData_getUopNode (test->edata); | |
299 | t2 = exprData_getUopNode (inc->edata); | |
300 | if (sRef_sameName (t1->sref, t2->sref) ) | |
301 | { | |
302 | return (constraintExpr_makeMaxSetExpr (t1) ); | |
303 | } | |
304 | } | |
305 | llassert ( FALSE); | |
306 | BADEXIT; | |
307 | } | |
308 | ||
309 | /*@access constraintExpr @*/ | |
310 | ||
311 | static /*@only@*/ constraintExpr constraintExpr_searchAndAdd (/*@only@*/ constraintExpr c, /*@observer@*/ constraintExpr find, /*@observer@*/ constraintExpr add) | |
312 | { | |
313 | constraintExprKind kind; | |
314 | constraintExpr temp; | |
315 | ||
316 | DPRINTF (( message ("Doing constraintExpr_searchAndAdd %s %s %s ", | |
317 | constraintExpr_unparse (c), constraintExpr_unparse (find), constraintExpr_unparse (add) ) ) ); | |
318 | ||
319 | if ( constraintExpr_similar (c, find) ) | |
320 | { | |
321 | ||
322 | constraintExpr newExpr; | |
323 | ||
324 | cstring cPrint; | |
325 | ||
326 | cPrint = constraintExpr_unparse (c); | |
327 | ||
328 | ||
329 | newExpr = constraintExpr_makeAddExpr (c, constraintExpr_copy (add) ); | |
330 | ||
331 | DPRINTF ((message ("Replacing %q with %q", | |
332 | cPrint, constraintExpr_unparse (newExpr) | |
333 | ))); | |
334 | return newExpr; | |
335 | } | |
336 | ||
337 | kind = c->kind; | |
338 | ||
339 | switch (kind) | |
340 | { | |
341 | case term: | |
342 | break; | |
343 | case unaryExpr: | |
344 | temp = constraintExprData_unaryExprGetExpr (c->data); | |
345 | temp = constraintExpr_searchAndAdd (constraintExpr_copy (temp), find, add); | |
346 | c->data = constraintExprData_unaryExprSetExpr (c->data, temp); | |
347 | break; | |
348 | case binaryexpr: | |
349 | ||
350 | temp = constraintExprData_binaryExprGetExpr1 (c->data); | |
351 | temp = constraintExpr_searchAndAdd (constraintExpr_copy (temp), find, add); | |
352 | c->data = constraintExprData_binaryExprSetExpr1 (c->data, temp); | |
353 | ||
354 | temp = constraintExprData_binaryExprGetExpr2 (c->data); | |
355 | temp = constraintExpr_searchAndAdd (constraintExpr_copy (temp), find, add); | |
356 | c->data = constraintExprData_binaryExprSetExpr2 (c->data, temp); | |
357 | break; | |
358 | default: | |
359 | llassert (FALSE); | |
360 | } | |
361 | return c; | |
362 | ||
363 | } | |
364 | ||
365 | /*@noaccess constraintExpr @*/ | |
366 | ||
367 | static constraint constraint_searchAndAdd (/*@returned@*/ constraint c, /*@observer@*/ constraintExpr find, /*@observer@*/ constraintExpr add) | |
368 | { | |
369 | ||
370 | llassert (constraint_search (c, find) ); | |
371 | DPRINTF (( message ("Doing constraint_searchAndAdd %s %s %s ", | |
372 | constraint_print (c), constraintExpr_unparse (find), constraintExpr_unparse (add) ) ) ); | |
373 | ||
374 | c->lexpr = constraintExpr_searchAndAdd (c->lexpr, find, add); | |
375 | c->expr = constraintExpr_searchAndAdd (c->expr, find, add); | |
376 | ||
377 | c = constraint_simplify (c); | |
378 | c = constraint_simplify (c); | |
379 | ||
380 | return c; | |
381 | ||
382 | } | |
383 | ||
384 | static constraintList constraintList_searchAndAdd (/*@returned@*/ constraintList list, | |
385 | /*@observer@*/ constraintExpr find, /*@observer@*/ constraintExpr add) | |
386 | { | |
387 | constraintList newConstraints; | |
388 | constraintList ret; | |
389 | ||
390 | newConstraints = constraintList_makeNew (); | |
391 | ||
392 | constraintList_elements (list, el) | |
393 | { | |
394 | if (constraint_search (el, find) ) | |
395 | { | |
396 | constraint newExpr; | |
397 | newExpr = constraint_copy (el); | |
398 | ||
399 | newExpr = constraint_searchAndAdd (newExpr, find, add); | |
400 | DPRINTF (( (message ("Adding constraint %s ", constraint_print (newExpr)) ) )); | |
401 | newConstraints = constraintList_add (newConstraints, newExpr); | |
402 | } | |
403 | ||
404 | } | |
405 | end_constraintList_elements; | |
406 | ||
407 | ret = constraintList_addListFree (list, newConstraints); | |
408 | return ret; | |
409 | } | |
410 | ||
411 | static void doAdjust (/*@unused@*/ exprNode e, /*@unused@*/ exprNode forPred, /*@observer@*/ exprNode forBody, /*@observer@*/ constraintExpr iterations) | |
412 | { | |
413 | ||
414 | constraintList_elements (forBody->ensuresConstraints, el) | |
415 | { | |
416 | /* look for var = var + 1 */ | |
417 | if (incVar (el) ) | |
418 | { | |
419 | DPRINTF ((message ("Found inc variable constraint : %s", constraint_print (el) ) )); | |
420 | forBody->requiresConstraints = constraintList_searchAndAdd (forBody->requiresConstraints, el->lexpr, iterations); | |
421 | } | |
422 | } | |
423 | end_constraintList_elements; | |
424 | } | |
425 | ||
426 | void exprNode_forLoopHeuristics ( exprNode e, exprNode forPred, exprNode forBody) | |
427 | { | |
428 | exprNode init, test, inc; | |
429 | ||
430 | constraintExpr iterations; | |
431 | ||
432 | init = exprData_getTripleInit (forPred->edata); | |
433 | test = exprData_getTripleTest (forPred->edata); | |
434 | inc = exprData_getTripleInc (forPred->edata); | |
435 | ||
436 | if (exprNode_isError (test) || exprNode_isError (inc) ) | |
437 | return; | |
438 | ||
439 | iterations = getForTimes (forPred, forBody ); | |
440 | ||
441 | if (constraintExpr_isDefined (iterations) ) | |
442 | { | |
443 | doAdjust ( e, forPred, forBody, iterations); | |
444 | constraintExpr_free (iterations); | |
445 | } | |
446 | } | |
447 | ||
448 | ||
449 | /* else */ | |
450 | /* { */ | |
451 | /* DPRINTF (("Can't get for time ")); */ | |
452 | /* } */ | |
453 | ||
454 | /* if (exprNode_isError (init) ) */ | |
455 | /* { */ | |
456 | /* return; */ | |
457 | /* } */ | |
458 | ||
459 | /* if (init->kind == XPR_ASSIGN) */ | |
460 | /* { */ | |
461 | /* t1 = exprData_getOpA (init->edata); */ | |
462 | /* t2 = exprData_getOpB (init->edata); */ | |
463 | ||
464 | /* if (! (t1->kind == XPR_VAR) ) */ | |
465 | /* return; */ | |
466 | /* } */ | |
467 | /* else */ | |
468 | /* return; */ | |
469 | ||
470 | /* if (test->kind == XPR_FETCH) */ | |
471 | /* { */ | |
472 | /* t3 = exprData_getPairA (test->edata); */ | |
473 | /* t4 = exprData_getPairB (test->edata); */ | |
474 | ||
475 | /* if (sRef_sameName (t1->sref, t4->sref) ) */ | |
476 | /* { */ | |
477 | /* DPRINTF ((message ("Found a for loop matching heuristic:%s", exprNode_unparse (forPred) ) )); */ | |
478 | /* con = constraint_makeEnsureLteMaxRead (t1, t3); */ | |
479 | /* forPred->ensuresConstraints = constraintList_add (forPred->ensuresConstraints, con); */ | |
480 | /* } */ | |
481 | /* else */ | |
482 | /* { */ | |
483 | /* DPRINTF ((message ("Didn't Find a for loop matching heuristic:%s %s and %s differ", exprNode_unparse (forPred), exprNode_unparse (t1), exprNode_unparse (t3) ) )); */ | |
484 | /* } */ | |
485 | /* return; */ | |
486 | /* } */ |