smatch_ranges.c

   1 /*
   2  * sparse/smatch_ranges.c
   3  *
   4  * Copyright (C) 2009 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include "parse.h"
  11 #include "smatch.h"
  12 #include "smatch_extra.h"
  13 #include "smatch_slist.h"
  14
  15 ALLOCATOR(data_info, "smatch extra data");
  16 ALLOCATOR(data_range, "data range");
  17 __DO_ALLOCATOR(struct data_range, sizeof(struct data_range), __alignof__(struct data_range),
  18                          "permanent ranges", perm_data_range);
  19
  20 struct data_range whole_range = {
  21         .min = LLONG_MIN,
  22         .max = LLONG_MAX,
  23 };
  24
  25 static char *show_num(long long num)
  26 {
  27         static char buff[256];
  28
  29         if (num == whole_range.min)
  30                 snprintf(buff, 255, "min");
  31         else if (num == whole_range.max)
  32                 snprintf(buff, 255, "max");
  33         else if (num < 0)
  34                 snprintf(buff, 255, "(%lld)", num);
  35         else
  36                 snprintf(buff, 255, "%lld", num);
  37
  38         buff[255] = '\0';
  39         return buff;
  40 }
  41
  42 char *show_ranges(struct range_list *list)
  43 {
  44         struct data_range *tmp;
  45         char full[256];
  46         int i = 0;
  47
  48         full[0] = '\0';
  49         full[255] = '\0';
  50         FOR_EACH_PTR(list, tmp) {
  51                 if (i++)
  52                         strncat(full, ",", 254 - strlen(full));
  53                 if (tmp->min == tmp->max) {
  54                         strncat(full, show_num(tmp->min), 254 - strlen(full));
  55                         continue;
  56                 }
  57                 strncat(full, show_num(tmp->min), 254 - strlen(full));
  58                 strncat(full, "-", 254 - strlen(full));
  59                 strncat(full, show_num(tmp->max), 254 - strlen(full));
  60         } END_FOR_EACH_PTR(tmp);
  61         return alloc_sname(full);
  62 }
  63
  64 void get_value_ranges(char *value, struct range_list **rl)
  65 {
  66         long long val1, val2;
  67         char *start;
  68         char *c;
  69
  70         *rl = NULL;
  71
  72         c = value;
  73         while (*c) {
  74                 if (*c == '(')
  75                         c++;
  76                 start = c;
  77                 if (!strncmp(start, "min", 3)) {
  78                         val1 = LLONG_MIN;
  79                         c += 3;
  80                 } else {
  81                         while (*c && *c != ',' && *c != '-')
  82                                 c++;
  83                         val1 = strtoll(start, &c, 10);
  84                 }
  85                 if (*c == ')')
  86                         c++;
  87                 if (!*c) {
  88                         add_range(rl, val1, val1);
  89                         break;
  90                 }
  91                 if (*c == ',') {
  92                         add_range(rl, val1, val1);
  93                         c++;
  94                         start = c;
  95                         continue;
  96                 }
  97                 c++; /* skip the dash in eg. 4-5 */
  98                 if (*c == '(')
  99                         c++;
 100                 start = c;
 101                 if (!strncmp(start, "max", 3)) {
 102                         val2 = LLONG_MAX;
 103                         c += 3;
 104                 } else {
 105
 106                         while (*c && *c != ',' && *c != '-')
 107                                 c++;
 108                         val2 = strtoll(start, &c, 10);
 109                 }
 110                 add_range(rl, val1, val2);
 111                 if (!*c)
 112                         break;
 113                 if (*c == ')')
 114                         c++;
 115                 c++; /* skip the comma in eg: 4-5,7 */
 116         }
 117
 118 }
 119
 120 static struct data_range range_zero = {
 121         .min = 0,
 122         .max = 0,
 123 };
 124
 125 static struct data_range range_one = {
 126         .min = 1,
 127         .max = 1,
 128 };
 129
 130 int is_whole_range_rl(struct range_list *rl)
 131 {
 132         struct data_range *drange;
 133
 134         if (ptr_list_empty(rl))
 135                 return 1;
 136         drange = first_ptr_list((struct ptr_list *)rl);
 137         if (drange->min == whole_range.min && drange->max == whole_range.max)
 138                 return 1;
 139         return 0;
 140 }
 141
 142 long long rl_min(struct range_list *rl)
 143 {
 144         struct data_range *drange;
 145
 146         if (ptr_list_empty(rl))
 147                 return whole_range.min;
 148         drange = first_ptr_list((struct ptr_list *)rl);
 149         return drange->min;
 150 }
 151
 152 long long rl_max(struct range_list *rl)
 153 {
 154         struct data_range *drange;
 155
 156         if (ptr_list_empty(rl))
 157                 return whole_range.max;
 158         drange = last_ptr_list((struct ptr_list *)rl);
 159         return drange->max;
 160 }
 161
 162 static struct data_range *alloc_range_helper(long long min, long long max, int perm)
 163 {
 164         struct data_range *ret;
 165
 166         if (min > max) {
 167                 sm_msg("Error invalid range %lld to %lld", min, max);
 168                 min = whole_range.min;
 169                 max = whole_range.max;
 170         }
 171         if (min == whole_range.min && max == whole_range.max)
 172                 return &whole_range;
 173         if (min == 0 && max == 0)
 174                 return &range_zero;
 175         if (min == 1 && max == 1)
 176                 return &range_one;
 177
 178         if (perm)
 179                 ret = __alloc_perm_data_range(0);
 180         else
 181                 ret = __alloc_data_range(0);
 182         ret->min = min;
 183         ret->max = max;
 184         return ret;
 185 }
 186
 187 struct data_range *alloc_range(long long min, long long max)
 188 {
 189         return alloc_range_helper(min, max, 0);
 190 }
 191
 192 struct data_range *alloc_range_perm(long long min, long long max)
 193 {
 194         return alloc_range_helper(min, max, 1);
 195 }
 196
 197 struct range_list *alloc_range_list(long long min, long long max)
 198 {
 199         struct range_list *rl = NULL;
 200
 201         add_range(&rl, min, max);
 202         return rl;
 203 }
 204
 205 void add_range(struct range_list **list, long long min, long long max)
 206 {
 207         struct data_range *tmp = NULL;
 208         struct data_range *new = NULL;
 209         int check_next = 0;
 210
 211         /*
 212          * FIXME:  This has a problem merging a range_list like: min-0,3-max
 213          * with a range like 1-2.  You end up with min-2,3-max instead of
 214          * just min-max.
 215          */
 216         FOR_EACH_PTR(*list, tmp) {
 217                 if (check_next) {
 218                         /* Sometimes we overlap with more than one range
 219                            so we have to delete or modify the next range. */
 220                         if (max + 1 == tmp->min) {
 221                                 /* join 2 ranges here */
 222                                 new->max = tmp->max;
 223                                 DELETE_CURRENT_PTR(tmp);
 224                                 return;
 225                         }
 226
 227                         /* Doesn't overlap with the next one. */
 228                         if (max < tmp->min)
 229                                 return;
 230                         /* Partially overlaps with the next one. */
 231                         if (max < tmp->max) {
 232                                 tmp->min = max + 1;
 233                                 return;
 234                         }
 235                         /* Completely overlaps with the next one. */
 236                         if (max >= tmp->max) {
 237                                 DELETE_CURRENT_PTR(tmp);
 238                                 /* there could be more ranges to delete */
 239                                 continue;
 240                         }
 241                 }
 242                 if (max != whole_range.max && max + 1 == tmp->min) {
 243                         /* join 2 ranges into a big range */
 244                         new = alloc_range(min, tmp->max);
 245                         REPLACE_CURRENT_PTR(tmp, new);
 246                         return;
 247                 }
 248                 if (max < tmp->min) {  /* new range entirely below */
 249                         new = alloc_range(min, max);
 250                         INSERT_CURRENT(new, tmp);
 251                         return;
 252                 }
 253                 if (min < tmp->min) { /* new range partially below */
 254                         if (max < tmp->max)
 255                                 max = tmp->max;
 256                         else
 257                                 check_next = 1;
 258                         new = alloc_range(min, max);
 259                         REPLACE_CURRENT_PTR(tmp, new);
 260                         if (!check_next)
 261                                 return;
 262                         continue;
 263                 }
 264                 if (max <= tmp->max) /* new range already included */
 265                         return;
 266                 if (min <= tmp->max) { /* new range partially above */
 267                         min = tmp->min;
 268                         new = alloc_range(min, max);
 269                         REPLACE_CURRENT_PTR(tmp, new);
 270                         check_next = 1;
 271                         continue;
 272                 }
 273                 if (min != whole_range.min && min - 1 == tmp->max) {
 274                         /* join 2 ranges into a big range */
 275                         new = alloc_range(tmp->min, max);
 276                         REPLACE_CURRENT_PTR(tmp, new);
 277                         check_next = 1;
 278                         continue;
 279                 }
 280                 /* the new range is entirely above the existing ranges */
 281         } END_FOR_EACH_PTR(tmp);
 282         if (check_next)
 283                 return;
 284         new = alloc_range(min, max);
 285         add_ptr_list(list, new);
 286 }
 287
 288 struct range_list *clone_range_list(struct range_list *list)
 289 {
 290         struct data_range *tmp;
 291         struct range_list *ret = NULL;
 292
 293         FOR_EACH_PTR(list, tmp) {
 294                 add_ptr_list(&ret, tmp);
 295         } END_FOR_EACH_PTR(tmp);
 296         return ret;
 297 }
 298
 299 struct range_list *range_list_union(struct range_list *one, struct range_list *two)
 300 {
 301         struct data_range *tmp;
 302         struct range_list *ret = NULL;
 303
 304         FOR_EACH_PTR(one, tmp) {
 305                 add_range(&ret, tmp->min, tmp->max);
 306         } END_FOR_EACH_PTR(tmp);
 307         FOR_EACH_PTR(two, tmp) {
 308                 add_range(&ret, tmp->min, tmp->max);
 309         } END_FOR_EACH_PTR(tmp);
 310         return ret;
 311 }
 312
 313 struct range_list *remove_range(struct range_list *list, long long min, long long max)
 314 {
 315         struct data_range *tmp;
 316         struct range_list *ret = NULL;
 317
 318         FOR_EACH_PTR(list, tmp) {
 319                 if (tmp->max < min) {
 320                         add_range(&ret, tmp->min, tmp->max);
 321                         continue;
 322                 }
 323                 if (tmp->min > max) {
 324                         add_range(&ret, tmp->min, tmp->max);
 325                         continue;
 326                 }
 327                 if (tmp->min >= min && tmp->max <= max)
 328                         continue;
 329                 if (tmp->min >= min) {
 330                         add_range(&ret, max + 1, tmp->max);
 331                 } else if (tmp->max <= max) {
 332                         add_range(&ret, tmp->min, min - 1);
 333                 } else {
 334                         add_range(&ret, tmp->min, min - 1);
 335                         add_range(&ret, max + 1, tmp->max);
 336                 }
 337         } END_FOR_EACH_PTR(tmp);
 338         return ret;
 339 }
 340
 341 /*
 342  * if it can be only one and only value return 1, else return 0
 343  */
 344 int estate_get_single_value(struct smatch_state *state, long long *val)
 345 {
 346         struct data_info *dinfo;
 347         struct data_range *tmp;
 348         int count = 0;
 349
 350         dinfo = get_dinfo(state);
 351         if (!dinfo || dinfo->type != DATA_RANGE)
 352                 return 0;
 353
 354         FOR_EACH_PTR(dinfo->value_ranges, tmp) {
 355                 if (!count++) {
 356                         if (tmp->min != tmp->max)
 357                                 return 0;
 358                         *val = tmp->min;
 359                 } else {
 360                         return 0;
 361                 }
 362         } END_FOR_EACH_PTR(tmp);
 363         return count;
 364 }
 365
 366 int true_comparison_range(struct data_range *left, int comparison, struct data_range *right)
 367 {
 368         switch (comparison) {
 369         case '<':
 370         case SPECIAL_UNSIGNED_LT:
 371                 if (left->min < right->max)
 372                         return 1;
 373                 return 0;
 374         case SPECIAL_UNSIGNED_LTE:
 375         case SPECIAL_LTE:
 376                 if (left->min <= right->max)
 377                         return 1;
 378                 return 0;
 379         case SPECIAL_EQUAL:
 380                 if (left->max < right->min)
 381                         return 0;
 382                 if (left->min > right->max)
 383                         return 0;
 384                 return 1;
 385         case SPECIAL_UNSIGNED_GTE:
 386         case SPECIAL_GTE:
 387                 if (left->max >= right->min)
 388                         return 1;
 389                 return 0;
 390         case '>':
 391         case SPECIAL_UNSIGNED_GT:
 392                 if (left->max > right->min)
 393                         return 1;
 394                 return 0;
 395         case SPECIAL_NOTEQUAL:
 396                 if (left->min != left->max)
 397                         return 1;
 398                 if (right->min != right->max)
 399                         return 1;
 400                 if (left->min != right->min)
 401                         return 1;
 402                 return 0;
 403         default:
 404                 sm_msg("unhandled comparison %d\n", comparison);
 405                 return 0;
 406         }
 407         return 0;
 408 }
 409
 410 int true_comparison_range_lr(int comparison, struct data_range *var, struct data_range *val, int left)
 411 {
 412         if (left)
 413                 return true_comparison_range(var, comparison, val);
 414         else
 415                 return true_comparison_range(val, comparison, var);
 416 }
 417
 418 static int false_comparison_range(struct data_range *left, int comparison, struct data_range *right)
 419 {
 420         switch (comparison) {
 421         case '<':
 422         case SPECIAL_UNSIGNED_LT:
 423                 if (left->max >= right->min)
 424                         return 1;
 425                 return 0;
 426         case SPECIAL_UNSIGNED_LTE:
 427         case SPECIAL_LTE:
 428                 if (left->max > right->min)
 429                         return 1;
 430                 return 0;
 431         case SPECIAL_EQUAL:
 432                 if (left->min != left->max)
 433                         return 1;
 434                 if (right->min != right->max)
 435                         return 1;
 436                 if (left->min != right->min)
 437                         return 1;
 438                 return 0;
 439         case SPECIAL_UNSIGNED_GTE:
 440         case SPECIAL_GTE:
 441                 if (left->min < right->max)
 442                         return 1;
 443                 return 0;
 444         case '>':
 445         case SPECIAL_UNSIGNED_GT:
 446                 if (left->min <= right->max)
 447                         return 1;
 448                 return 0;
 449         case SPECIAL_NOTEQUAL:
 450                 if (left->max < right->min)
 451                         return 0;
 452                 if (left->min > right->max)
 453                         return 0;
 454                 return 1;
 455         default:
 456                 sm_msg("unhandled comparison %d\n", comparison);
 457                 return 0;
 458         }
 459         return 0;
 460 }
 461
 462 int false_comparison_range_lr(int comparison, struct data_range *var, struct data_range *val, int left)
 463 {
 464         if (left)
 465                 return false_comparison_range(var, comparison, val);
 466         else
 467                 return false_comparison_range(val, comparison, var);
 468 }
 469
 470 int possibly_true(struct expression *left, int comparison, struct expression *right)
 471 {
 472         struct range_list *rl_left, *rl_right;
 473         struct data_range *tmp_left, *tmp_right;
 474
 475         if (!get_implied_range_list(left, &rl_left))
 476                 return 1;
 477         if (!get_implied_range_list(right, &rl_right))
 478                 return 1;
 479
 480         FOR_EACH_PTR(rl_left, tmp_left) {
 481                 FOR_EACH_PTR(rl_right, tmp_right) {
 482                         if (true_comparison_range(tmp_left, comparison, tmp_right))
 483                                 return 1;
 484                 } END_FOR_EACH_PTR(tmp_right);
 485         } END_FOR_EACH_PTR(tmp_left);
 486         return 0;
 487 }
 488
 489 int possibly_false(struct expression *left, int comparison, struct expression *right)
 490 {
 491         struct range_list *rl_left, *rl_right;
 492         struct data_range *tmp_left, *tmp_right;
 493
 494         if (!get_implied_range_list(left, &rl_left))
 495                 return 1;
 496         if (!get_implied_range_list(right, &rl_right))
 497                 return 1;
 498
 499         FOR_EACH_PTR(rl_left, tmp_left) {
 500                 FOR_EACH_PTR(rl_right, tmp_right) {
 501                         if (false_comparison_range(tmp_left, comparison, tmp_right))
 502                                 return 1;
 503                 } END_FOR_EACH_PTR(tmp_right);
 504         } END_FOR_EACH_PTR(tmp_left);
 505         return 0;
 506 }
 507
 508 int possibly_true_range_lists(struct range_list *left_ranges, int comparison, struct range_list *right_ranges)
 509 {
 510         struct data_range *left_tmp, *right_tmp;
 511
 512         if (!left_ranges || !right_ranges)
 513                 return 1;
 514
 515         FOR_EACH_PTR(left_ranges, left_tmp) {
 516                 FOR_EACH_PTR(right_ranges, right_tmp) {
 517                         if (true_comparison_range(left_tmp, comparison, right_tmp))
 518                                 return 1;
 519                 } END_FOR_EACH_PTR(right_tmp);
 520         } END_FOR_EACH_PTR(left_tmp);
 521         return 0;
 522 }
 523
 524 int possibly_true_range_list_lr(int comparison, struct smatch_state *state, struct range_list *values, int left)
 525 {
 526         struct data_range *tmp, *tmp2;
 527
 528         FOR_EACH_PTR(estate_ranges(state), tmp) {
 529                 FOR_EACH_PTR(values, tmp2) {
 530                         if (true_comparison_range_lr(comparison, tmp, tmp2, left))
 531                                 return 1;
 532                 } END_FOR_EACH_PTR(tmp2);
 533         } END_FOR_EACH_PTR(tmp);
 534         return 0;
 535 }
 536
 537 int possibly_false_range_lists(struct range_list *left_ranges, int comparison, struct range_list *right_ranges)
 538 {
 539         struct data_range *left_tmp, *right_tmp;
 540
 541         if (!left_ranges || !right_ranges)
 542                 return 1;
 543
 544         FOR_EACH_PTR(left_ranges, left_tmp) {
 545                 FOR_EACH_PTR(right_ranges, right_tmp) {
 546                         if (false_comparison_range(left_tmp, comparison, right_tmp))
 547                                 return 1;
 548                 } END_FOR_EACH_PTR(right_tmp);
 549         } END_FOR_EACH_PTR(left_tmp);
 550         return 0;
 551 }
 552
 553 int possibly_false_range_list_lr(int comparison, struct smatch_state *state, struct range_list *values, int left)
 554 {
 555         struct data_range *tmp, *tmp2;
 556
 557         FOR_EACH_PTR(estate_ranges(state), tmp) {
 558                 FOR_EACH_PTR(values, tmp2) {
 559                         if (false_comparison_range_lr(comparison, tmp, tmp2, left))
 560                                 return 1;
 561                 } END_FOR_EACH_PTR(tmp2);
 562         } END_FOR_EACH_PTR(tmp);
 563         return 0;
 564 }
 565
 566 void tack_on(struct range_list **list, struct data_range *drange)
 567 {
 568         add_ptr_list(list, drange);
 569 }
 570
 571 int in_list_exact(struct range_list *list, struct data_range *drange)
 572 {
 573         struct data_range *tmp;
 574
 575         FOR_EACH_PTR(list, tmp) {
 576                 if (tmp->min == drange->min && tmp->max == drange->max)
 577                         return 1;
 578         } END_FOR_EACH_PTR(tmp);
 579         return 0;
 580
 581 }
 582
 583 void push_range_list(struct range_list_stack **rl_stack, struct range_list *rl)
 584 {
 585         add_ptr_list(rl_stack, rl);
 586 }
 587
 588 struct range_list *pop_range_list(struct range_list_stack **rl_stack)
 589 {
 590         struct range_list *rl;
 591
 592         rl = last_ptr_list((struct ptr_list *)*rl_stack);
 593         delete_ptr_list_last((struct ptr_list **)rl_stack);
 594         return rl;
 595 }
 596
 597 struct range_list *top_range_list(struct range_list_stack *rl_stack)
 598 {
 599         struct range_list *rl;
 600
 601         rl = last_ptr_list((struct ptr_list *)rl_stack);
 602         return rl;
 603 }
 604
 605 void filter_top_range_list(struct range_list_stack **rl_stack, long long num)
 606 {
 607         struct range_list *rl;
 608
 609         rl = pop_range_list(rl_stack);
 610         rl = remove_range(rl, num, num);
 611         push_range_list(rl_stack, rl);
 612 }
 613
 614 void free_range_list(struct range_list **rlist)
 615 {
 616         __free_ptr_list((struct ptr_list **)rlist);
 617 }
 618
 619 static void free_single_dinfo(struct data_info *dinfo)
 620 {
 621         if (dinfo->type == DATA_RANGE)
 622                 free_range_list(&dinfo->value_ranges);
 623 }
 624
 625 static void free_dinfos(struct allocation_blob *blob)
 626 {
 627         unsigned int size = sizeof(struct data_info);
 628         unsigned int offset = 0;
 629
 630         while (offset < blob->offset) {
 631                 free_single_dinfo((struct data_info *)(blob->data + offset));
 632                 offset += size;
 633         }
 634 }
 635
 636 void free_data_info_allocs(void)
 637 {
 638         struct allocator_struct *desc = &data_info_allocator;
 639         struct allocation_blob *blob = desc->blobs;
 640
 641         desc->blobs = NULL;
 642         desc->allocations = 0;
 643         desc->total_bytes = 0;
 644         desc->useful_bytes = 0;
 645         desc->freelist = NULL;
 646         while (blob) {
 647                 struct allocation_blob *next = blob->next;
 648                 free_dinfos(blob);
 649                 blob_free(blob, desc->chunking);
 650                 blob = next;
 651         }
 652         clear_data_range_alloc();
 653 }
 654