smatch_estate.c

   1 /*
   2  * Copyright (C) 2010 Dan Carpenter.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, see http://www.gnu.org/copyleft/gpl.txt
  16  */
  17
  18 /*
  19  * smatch_dinfo.c has helper functions for handling data_info structs
  20  *
  21  */
  22
  23 #include <stdlib.h>
  24 #ifndef __USE_ISOC99
  25 #define __USE_ISOC99
  26 #endif
  27 #include <limits.h>
  28 #include "parse.h"
  29 #include "smatch.h"
  30 #include "smatch_slist.h"
  31 #include "smatch_extra.h"
  32
  33 struct smatch_state *merge_estates(struct smatch_state *s1, struct smatch_state *s2)
  34 {
  35         struct smatch_state *tmp;
  36         struct range_list *value_ranges;
  37         struct related_list *rlist;
  38         bool capped = false;
  39
  40         if (estates_equiv(s1, s2))
  41                 return s1;
  42
  43         value_ranges = rl_union(estate_rl(s1), estate_rl(s2));
  44         tmp = alloc_estate_rl(value_ranges);
  45         rlist = get_shared_relations(estate_related(s1), estate_related(s2));
  46         set_related(tmp, rlist);
  47
  48         if ((estate_has_hard_max(s1) && (!estate_rl(s2) || estate_has_hard_max(s2))) ||
  49             (estate_has_hard_max(s2) && (!estate_rl(s1) || estate_has_hard_max(s1))))
  50                 estate_set_hard_max(tmp);
  51
  52         estate_set_fuzzy_max(tmp, sval_max(estate_get_fuzzy_max(s1), estate_get_fuzzy_max(s2)));
  53
  54         if (estate_capped(s1) && estate_capped(s2))
  55                 capped = true;
  56         if (estate_rl(s1) && estate_rl(s2)) {
  57                 if (estate_capped(s1) && estate_max(s2).uvalue < 100)
  58                         capped = true;
  59                 if (estate_capped(s2) && estate_max(s1).uvalue < 100)
  60                         capped = true;
  61         }
  62         if (capped)
  63                 estate_set_capped(tmp);
  64
  65         if (estate_treat_untagged(s1) && estate_treat_untagged(s2))
  66                 estate_set_treat_untagged(tmp);
  67
  68         if (estate_assigned(s1) || estate_assigned(s2))
  69                 estate_set_assigned(tmp);
  70
  71         if (estate_new(s1) || estate_new(s2))
  72                 estate_set_new(tmp);
  73
  74         return tmp;
  75 }
  76
  77 struct data_info *get_dinfo(struct smatch_state *state)
  78 {
  79         if (!state)
  80                 return NULL;
  81         return (struct data_info *)state->data;
  82 }
  83
  84 struct range_list *estate_rl(struct smatch_state *state)
  85 {
  86         if (!state)
  87                 return NULL;
  88         return get_dinfo(state)->value_ranges;
  89 }
  90
  91 struct related_list *estate_related(struct smatch_state *state)
  92 {
  93         if (!state)
  94                 return NULL;
  95         return get_dinfo(state)->related;
  96 }
  97
  98 sval_t estate_get_fuzzy_max(struct smatch_state *state)
  99 {
 100         sval_t empty = {};
 101
 102         if (!state || !get_dinfo(state))
 103                 return empty;
 104         return get_dinfo(state)->fuzzy_max;
 105 }
 106
 107 int estate_has_fuzzy_max(struct smatch_state *state)
 108 {
 109         if (estate_get_fuzzy_max(state).type)
 110                 return 1;
 111         return 0;
 112 }
 113
 114 void estate_set_fuzzy_max(struct smatch_state *state, sval_t fuzzy_max)
 115 {
 116         if (is_ptr_type(estate_type(state)))
 117                 return;
 118         if (!rl_has_sval(estate_rl(state), fuzzy_max))
 119                 return;
 120         get_dinfo(state)->fuzzy_max = fuzzy_max;
 121 }
 122
 123 void estate_copy_fuzzy_max(struct smatch_state *new, struct smatch_state *old)
 124 {
 125         if (is_ptr_type(estate_type(new)))
 126                 return;
 127         if (!estate_has_fuzzy_max(old))
 128                 return;
 129         estate_set_fuzzy_max(new, estate_get_fuzzy_max(old));
 130 }
 131
 132 void estate_clear_fuzzy_max(struct smatch_state *state)
 133 {
 134         sval_t empty = {};
 135
 136         get_dinfo(state)->fuzzy_max = empty;
 137 }
 138
 139 int estate_has_hard_max(struct smatch_state *state)
 140 {
 141         if (!state || !estate_rl(state))
 142                 return 0;
 143         return get_dinfo(state)->hard_max;
 144 }
 145
 146 void estate_set_hard_max(struct smatch_state *state)
 147 {
 148         /* pointers don't have a hard max */
 149         if (is_ptr_type(estate_type(state)))
 150                 return;
 151         get_dinfo(state)->hard_max = 1;
 152 }
 153
 154 void estate_clear_hard_max(struct smatch_state *state)
 155 {
 156         get_dinfo(state)->hard_max = 0;
 157 }
 158
 159 int estate_get_hard_max(struct smatch_state *state, sval_t *sval)
 160 {
 161         if (!state || !get_dinfo(state)->hard_max || !estate_rl(state))
 162                 return 0;
 163         *sval = rl_max(estate_rl(state));
 164         return 1;
 165 }
 166
 167 bool estate_capped(struct smatch_state *state)
 168 {
 169         if (!state)
 170                 return false;
 171         /* impossible states are capped */
 172         if (!estate_rl(state))
 173                 return true;
 174         return get_dinfo(state)->capped;
 175 }
 176
 177 void estate_set_capped(struct smatch_state *state)
 178 {
 179         get_dinfo(state)->capped = true;
 180 }
 181
 182 bool estate_treat_untagged(struct smatch_state *state)
 183 {
 184         if (!state)
 185                 return false;
 186
 187         /* impossible states are capped */
 188         if (!estate_rl(state))
 189                 return true;
 190
 191         return get_dinfo(state)->treat_untagged;
 192 }
 193
 194 void estate_set_treat_untagged(struct smatch_state *state)
 195 {
 196         get_dinfo(state)->treat_untagged = true;
 197 }
 198
 199 bool estate_assigned(struct smatch_state *state)
 200 {
 201         if (!estate_rl(state))
 202                 return false;
 203         return get_dinfo(state)->assigned;
 204 }
 205
 206 void estate_set_assigned(struct smatch_state *state)
 207 {
 208         get_dinfo(state)->assigned = true;
 209 }
 210
 211 bool estate_new(struct smatch_state *state)
 212 {
 213         if (!estate_rl(state))
 214                 return false;
 215         return get_dinfo(state)->set;
 216 }
 217
 218 void estate_set_new(struct smatch_state *state)
 219 {
 220         get_dinfo(state)->set = true;
 221 }
 222
 223 sval_t estate_min(struct smatch_state *state)
 224 {
 225         return rl_min(estate_rl(state));
 226 }
 227
 228 sval_t estate_max(struct smatch_state *state)
 229 {
 230         return rl_max(estate_rl(state));
 231 }
 232
 233 struct symbol *estate_type(struct smatch_state *state)
 234 {
 235         return rl_max(estate_rl(state)).type;
 236 }
 237
 238 static int rlists_equiv(struct related_list *one, struct related_list *two)
 239 {
 240         struct relation *one_rel;
 241         struct relation *two_rel;
 242
 243         PREPARE_PTR_LIST(one, one_rel);
 244         PREPARE_PTR_LIST(two, two_rel);
 245         for (;;) {
 246                 if (!one_rel && !two_rel)
 247                         return 1;
 248                 if (!one_rel || !two_rel)
 249                         return 0;
 250                 if (one_rel->sym != two_rel->sym)
 251                         return 0;
 252                 if (strcmp(one_rel->name, two_rel->name))
 253                         return 0;
 254                 NEXT_PTR_LIST(one_rel);
 255                 NEXT_PTR_LIST(two_rel);
 256         }
 257         FINISH_PTR_LIST(two_rel);
 258         FINISH_PTR_LIST(one_rel);
 259
 260         return 1;
 261 }
 262
 263 int estates_equiv(struct smatch_state *one, struct smatch_state *two)
 264 {
 265         if (!one || !two)
 266                 return 0;
 267         if (one == two)
 268                 return 1;
 269         if (!rlists_equiv(estate_related(one), estate_related(two)))
 270                 return 0;
 271         if (estate_capped(one) != estate_capped(two))
 272                 return 0;
 273         if (estate_treat_untagged(one) != estate_treat_untagged(two))
 274                 return 0;
 275         if (estate_has_hard_max(one) != estate_has_hard_max(two))
 276                 return 0;
 277         if (estate_new(one) != estate_new(two))
 278                 return 0;
 279         if (strcmp(one->name, two->name) == 0)
 280                 return 1;
 281         return 0;
 282 }
 283
 284 int estate_is_whole(struct smatch_state *state)
 285 {
 286         return is_whole_rl(estate_rl(state));
 287 }
 288
 289 int estate_is_empty(struct smatch_state *state)
 290 {
 291         return state && !estate_rl(state);
 292 }
 293
 294 int estate_is_unknown(struct smatch_state *state)
 295 {
 296         if (!estate_is_whole(state))
 297                 return 0;
 298         if (estate_related(state))
 299                 return 0;
 300         if (estate_has_fuzzy_max(state))
 301                 return 0;
 302         return 1;
 303 }
 304
 305 int estate_get_single_value(struct smatch_state *state, sval_t *sval)
 306 {
 307         sval_t min, max;
 308
 309         if (!estate_rl(state))
 310                 return 0;
 311         min = rl_min(estate_rl(state));
 312         max = rl_max(estate_rl(state));
 313         if (sval_cmp(min, max) != 0)
 314                 return 0;
 315         *sval = min;
 316         return 1;
 317 }
 318
 319 static struct data_info *alloc_dinfo(void)
 320 {
 321         struct data_info *ret;
 322
 323         ret = __alloc_data_info(0);
 324         memset(ret, 0, sizeof(*ret));
 325         return ret;
 326 }
 327
 328 static struct data_info *alloc_dinfo_range(sval_t min, sval_t max)
 329 {
 330         struct data_info *ret;
 331
 332         ret = alloc_dinfo();
 333         add_range(&ret->value_ranges, min, max);
 334         return ret;
 335 }
 336
 337 static struct data_info *alloc_dinfo_range_list(struct range_list *rl)
 338 {
 339         struct data_info *ret;
 340
 341         ret = alloc_dinfo();
 342         ret->value_ranges = rl;
 343         return ret;
 344 }
 345
 346 static struct data_info *clone_dinfo(struct data_info *dinfo)
 347 {
 348         struct data_info *ret;
 349
 350         ret = alloc_dinfo();
 351         ret->related = clone_related_list(dinfo->related);
 352         ret->value_ranges = clone_rl(dinfo->value_ranges);
 353         ret->hard_max = dinfo->hard_max;
 354         ret->fuzzy_max = dinfo->fuzzy_max;
 355         return ret;
 356 }
 357
 358 struct smatch_state *clone_estate(struct smatch_state *state)
 359 {
 360         struct smatch_state *ret;
 361
 362         if (!state)
 363                 return NULL;
 364
 365         ret = __alloc_smatch_state(0);
 366         ret->name = state->name;
 367         ret->data = clone_dinfo(get_dinfo(state));
 368         return ret;
 369 }
 370
 371 struct smatch_state *clone_partial_estate(struct smatch_state *state, struct range_list *rl)
 372 {
 373         struct smatch_state *ret;
 374
 375         if (!state)
 376                 return NULL;
 377
 378         rl = cast_rl(estate_type(state), rl);
 379
 380         ret = alloc_estate_rl(rl);
 381         set_related(ret, clone_related_list(estate_related(state)));
 382         if (estate_has_hard_max(state))
 383                 estate_set_hard_max(ret);
 384         if (estate_has_fuzzy_max(state))
 385                 estate_set_fuzzy_max(ret, estate_get_fuzzy_max(state));
 386
 387         return ret;
 388 }
 389
 390 struct smatch_state *alloc_estate_empty(void)
 391 {
 392         struct smatch_state *state;
 393         struct data_info *dinfo;
 394
 395         dinfo = alloc_dinfo();
 396         state = __alloc_smatch_state(0);
 397         state->data = dinfo;
 398         state->name = "";
 399         return state;
 400 }
 401
 402 struct smatch_state *alloc_estate_whole(struct symbol *type)
 403 {
 404         return alloc_estate_rl(alloc_whole_rl(type));
 405 }
 406
 407 struct smatch_state *extra_empty(void)
 408 {
 409         struct smatch_state *ret;
 410
 411         ret = __alloc_smatch_state(0);
 412         ret->name = "empty";
 413         ret->data = alloc_dinfo();
 414         return ret;
 415 }
 416
 417 struct smatch_state *alloc_estate_sval(sval_t sval)
 418 {
 419         struct smatch_state *state;
 420
 421         state = __alloc_smatch_state(0);
 422         state->data = alloc_dinfo_range(sval, sval);
 423         state->name = show_rl(get_dinfo(state)->value_ranges);
 424         estate_set_hard_max(state);
 425         estate_set_fuzzy_max(state, sval);
 426         return state;
 427 }
 428
 429 struct smatch_state *alloc_estate_range(sval_t min, sval_t max)
 430 {
 431         struct smatch_state *state;
 432
 433         state = __alloc_smatch_state(0);
 434         state->data = alloc_dinfo_range(min, max);
 435         state->name = show_rl(get_dinfo(state)->value_ranges);
 436         return state;
 437 }
 438
 439 struct smatch_state *alloc_estate_rl(struct range_list *rl)
 440 {
 441         struct smatch_state *state;
 442
 443         if (!rl)
 444                 return extra_empty();
 445
 446         state = __alloc_smatch_state(0);
 447         state->data = alloc_dinfo_range_list(rl);
 448         state->name = show_rl(rl);
 449         return state;
 450 }
 451
 452 struct smatch_state *clone_estate_cast(struct symbol *type, struct smatch_state *state)
 453 {
 454         struct smatch_state *ret;
 455         struct data_info *dinfo;
 456
 457         if (!state)
 458                 return NULL;
 459
 460         dinfo = alloc_dinfo();
 461         dinfo->value_ranges = clone_rl(cast_rl(type, estate_rl(state)));
 462
 463         ret = __alloc_smatch_state(0);
 464         ret->name = show_rl(dinfo->value_ranges);
 465         ret->data = dinfo;
 466
 467         return ret;
 468 }
 469
 470 struct smatch_state *get_implied_estate(struct expression *expr)
 471 {
 472         struct smatch_state *state;
 473         struct range_list *rl;
 474
 475         state = get_state_expr(SMATCH_EXTRA, expr);
 476         if (state)
 477                 return state;
 478         if (!get_implied_rl(expr, &rl))
 479                 rl = alloc_whole_rl(get_type(expr));
 480         return alloc_estate_rl(rl);
 481 }
 482
 483 /*
 484  * One of the complications is that smatch tries to free a bunch of data at the
 485  * end of every function.
 486  */
 487 struct data_info *clone_dinfo_perm(struct data_info *dinfo)
 488 {
 489         struct data_info *ret;
 490
 491         ret = malloc(sizeof(*ret));
 492         memset(ret, 0, sizeof(*ret));
 493         ret->related = NULL;
 494         ret->value_ranges = clone_rl_permanent(dinfo->value_ranges);
 495         ret->hard_max = 0;
 496         ret->fuzzy_max = dinfo->fuzzy_max;
 497         return ret;
 498 }
 499
 500 struct smatch_state *clone_estate_perm(struct smatch_state *state)
 501 {
 502         struct smatch_state *ret;
 503
 504         ret = malloc(sizeof(*ret));
 505         ret->name = alloc_string(state->name);
 506         ret->data = clone_dinfo_perm(get_dinfo(state));
 507         return ret;
 508 }
 509
 510