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
  39         if (estates_equiv(s1, s2))
  40                 return s1;
  41
  42         value_ranges = rl_union(estate_rl(s1), estate_rl(s2));
  43         tmp = alloc_estate_rl(value_ranges);
  44         rlist = get_shared_relations(estate_related(s1), estate_related(s2));
  45         set_related(tmp, rlist);
  46         if (estate_has_hard_max(s1) && estate_has_hard_max(s2))
  47                 estate_set_hard_max(tmp);
  48
  49         estate_set_fuzzy_max(tmp, sval_max(estate_get_fuzzy_max(s1), estate_get_fuzzy_max(s2)));
  50
  51         return tmp;
  52 }
  53
  54 struct data_info *get_dinfo(struct smatch_state *state)
  55 {
  56         if (!state)
  57                 return NULL;
  58         return (struct data_info *)state->data;
  59 }
  60
  61 struct range_list *estate_rl(struct smatch_state *state)
  62 {
  63         if (!state)
  64                 return NULL;
  65         return get_dinfo(state)->value_ranges;
  66 }
  67
  68 struct related_list *estate_related(struct smatch_state *state)
  69 {
  70         if (!state)
  71                 return NULL;
  72         return get_dinfo(state)->related;
  73 }
  74
  75 sval_t estate_get_fuzzy_max(struct smatch_state *state)
  76 {
  77         sval_t empty = {};
  78
  79         if (!state || !get_dinfo(state))
  80                 return empty;
  81         return get_dinfo(state)->fuzzy_max;
  82 }
  83
  84 int estate_has_fuzzy_max(struct smatch_state *state)
  85 {
  86         if (estate_get_fuzzy_max(state).type)
  87                 return 1;
  88         return 0;
  89 }
  90
  91 void estate_set_fuzzy_max(struct smatch_state *state, sval_t fuzzy_max)
  92 {
  93         if (!rl_has_sval(estate_rl(state), fuzzy_max))
  94                 return;
  95         get_dinfo(state)->fuzzy_max = fuzzy_max;
  96 }
  97
  98 void estate_copy_fuzzy_max(struct smatch_state *new, struct smatch_state *old)
  99 {
 100         if (!estate_has_fuzzy_max(old))
 101                 return;
 102         estate_set_fuzzy_max(new, estate_get_fuzzy_max(old));
 103 }
 104
 105 void estate_clear_fuzzy_max(struct smatch_state *state)
 106 {
 107         sval_t empty = {};
 108
 109         get_dinfo(state)->fuzzy_max = empty;
 110 }
 111
 112 int estate_has_hard_max(struct smatch_state *state)
 113 {
 114         if (!state)
 115                 return 0;
 116         return get_dinfo(state)->hard_max;
 117 }
 118
 119 void estate_set_hard_max(struct smatch_state *state)
 120 {
 121          get_dinfo(state)->hard_max = 1;
 122 }
 123
 124 void estate_clear_hard_max(struct smatch_state *state)
 125 {
 126          get_dinfo(state)->hard_max = 0;
 127 }
 128
 129 int estate_get_hard_max(struct smatch_state *state, sval_t *sval)
 130 {
 131         if (!state || !get_dinfo(state)->hard_max || !estate_rl(state))
 132                 return 0;
 133         *sval = rl_max(estate_rl(state));
 134         return 1;
 135 }
 136
 137 sval_t estate_min(struct smatch_state *state)
 138 {
 139         return rl_min(estate_rl(state));
 140 }
 141
 142 sval_t estate_max(struct smatch_state *state)
 143 {
 144         return rl_max(estate_rl(state));
 145 }
 146
 147 struct symbol *estate_type(struct smatch_state *state)
 148 {
 149         return rl_max(estate_rl(state)).type;
 150 }
 151
 152 static int rlists_equiv(struct related_list *one, struct related_list *two)
 153 {
 154         struct relation *one_rel;
 155         struct relation *two_rel;
 156
 157         PREPARE_PTR_LIST(one, one_rel);
 158         PREPARE_PTR_LIST(two, two_rel);
 159         for (;;) {
 160                 if (!one_rel && !two_rel)
 161                         return 1;
 162                 if (!one_rel || !two_rel)
 163                         return 0;
 164                 if (one_rel->sym != two_rel->sym)
 165                         return 0;
 166                 if (strcmp(one_rel->name, two_rel->name))
 167                         return 0;
 168                 NEXT_PTR_LIST(one_rel);
 169                 NEXT_PTR_LIST(two_rel);
 170         }
 171         FINISH_PTR_LIST(two_rel);
 172         FINISH_PTR_LIST(one_rel);
 173
 174         return 1;
 175 }
 176
 177 int estates_equiv(struct smatch_state *one, struct smatch_state *two)
 178 {
 179         if (one == two)
 180                 return 1;
 181         if (!rlists_equiv(estate_related(one), estate_related(two)))
 182                 return 0;
 183         if (strcmp(one->name, two->name) == 0)
 184                 return 1;
 185         return 0;
 186 }
 187
 188 int estate_is_whole(struct smatch_state *state)
 189 {
 190         return is_whole_rl(estate_rl(state));
 191 }
 192
 193 int estate_is_unknown(struct smatch_state *state)
 194 {
 195         if (!estate_is_whole(state))
 196                 return 0;
 197         if (estate_related(state))
 198                 return 0;
 199         if (estate_has_fuzzy_max(state))
 200                 return 0;
 201         return 1;
 202 }
 203
 204 int estate_get_single_value(struct smatch_state *state, sval_t *sval)
 205 {
 206         sval_t min, max;
 207
 208         min = rl_min(estate_rl(state));
 209         max = rl_max(estate_rl(state));
 210         if (sval_cmp(min, max) != 0)
 211                 return 0;
 212         *sval = min;
 213         return 1;
 214 }
 215
 216 static struct data_info *alloc_dinfo(void)
 217 {
 218         struct data_info *ret;
 219
 220         ret = __alloc_data_info(0);
 221         memset(ret, 0, sizeof(*ret));
 222         return ret;
 223 }
 224
 225 static struct data_info *alloc_dinfo_range(sval_t min, sval_t max)
 226 {
 227         struct data_info *ret;
 228
 229         ret = alloc_dinfo();
 230         add_range(&ret->value_ranges, min, max);
 231         return ret;
 232 }
 233
 234 static struct data_info *alloc_dinfo_range_list(struct range_list *rl)
 235 {
 236         struct data_info *ret;
 237
 238         ret = alloc_dinfo();
 239         ret->value_ranges = rl;
 240         return ret;
 241 }
 242
 243 static struct data_info *clone_dinfo(struct data_info *dinfo)
 244 {
 245         struct data_info *ret;
 246
 247         ret = alloc_dinfo();
 248         ret->related = clone_related_list(dinfo->related);
 249         ret->value_ranges = clone_rl(dinfo->value_ranges);
 250         ret->hard_max = dinfo->hard_max;
 251         ret->fuzzy_max = dinfo->fuzzy_max;
 252         return ret;
 253 }
 254
 255 struct smatch_state *clone_estate(struct smatch_state *state)
 256 {
 257         struct smatch_state *ret;
 258
 259         ret = __alloc_smatch_state(0);
 260         ret->name = state->name;
 261         ret->data = clone_dinfo(get_dinfo(state));
 262         return ret;
 263 }
 264
 265 struct smatch_state *alloc_estate_empty(void)
 266 {
 267         struct smatch_state *state;
 268         struct data_info *dinfo;
 269
 270         dinfo = alloc_dinfo();
 271         state = __alloc_smatch_state(0);
 272         state->data = dinfo;
 273         state->name = "";
 274         return state;
 275 }
 276
 277 struct smatch_state *alloc_estate_whole(struct symbol *type)
 278 {
 279         return alloc_estate_rl(alloc_whole_rl(type));
 280 }
 281
 282 struct smatch_state *extra_empty(void)
 283 {
 284         struct smatch_state *ret;
 285
 286         ret = __alloc_smatch_state(0);
 287         ret->name = "empty";
 288         ret->data = alloc_dinfo();
 289         return ret;
 290 }
 291
 292 struct smatch_state *alloc_estate_sval(sval_t sval)
 293 {
 294         struct smatch_state *state;
 295
 296         state = __alloc_smatch_state(0);
 297         state->data = alloc_dinfo_range(sval, sval);
 298         state->name = show_rl(get_dinfo(state)->value_ranges);
 299         estate_set_hard_max(state);
 300         estate_set_fuzzy_max(state, sval);
 301         return state;
 302 }
 303
 304 struct smatch_state *alloc_estate_range(sval_t min, sval_t max)
 305 {
 306         struct smatch_state *state;
 307
 308         state = __alloc_smatch_state(0);
 309         state->data = alloc_dinfo_range(min, max);
 310         state->name = show_rl(get_dinfo(state)->value_ranges);
 311         return state;
 312 }
 313
 314 struct smatch_state *alloc_estate_rl(struct range_list *rl)
 315 {
 316         struct smatch_state *state;
 317
 318         if (!rl)
 319                 return extra_empty();
 320
 321         state = __alloc_smatch_state(0);
 322         state->data = alloc_dinfo_range_list(rl);
 323         state->name = show_rl(rl);
 324         return state;
 325 }
 326
 327 struct smatch_state *get_implied_estate(struct expression *expr)
 328 {
 329         struct smatch_state *state;
 330         struct range_list *rl;
 331
 332         state = get_state_expr(SMATCH_EXTRA, expr);
 333         if (state)
 334                 return state;
 335         if (!get_implied_rl(expr, &rl))
 336                 rl = alloc_whole_rl(get_type(expr));
 337         return alloc_estate_rl(rl);
 338 }
 339
 340 struct smatch_state *estate_filter_range(struct smatch_state *orig,
 341                                  sval_t filter_min, sval_t filter_max)
 342 {
 343         struct range_list *rl;
 344         struct smatch_state *state;
 345
 346         if (!orig)
 347                 orig = alloc_estate_whole(filter_min.type);
 348
 349         rl = remove_range(estate_rl(orig), filter_min, filter_max);
 350         state = alloc_estate_rl(rl);
 351         if (estate_has_hard_max(orig))
 352                 estate_set_hard_max(state);
 353         if (estate_has_fuzzy_max(orig))
 354                 estate_set_fuzzy_max(state, estate_get_fuzzy_max(orig));
 355         return state;
 356 }
 357
 358 struct smatch_state *estate_filter_sval(struct smatch_state *orig, sval_t sval)
 359 {
 360         return estate_filter_range(orig, sval, sval);
 361 }
 362
 363 /*
 364  * One of the complications is that smatch tries to free a bunch of data at the
 365  * end of every function.
 366  */
 367 struct data_info *clone_dinfo_perm(struct data_info *dinfo)
 368 {
 369         struct data_info *ret;
 370
 371         ret = malloc(sizeof(*ret));
 372         ret->related = NULL;
 373         ret->value_ranges = clone_rl_permanent(dinfo->value_ranges);
 374         ret->hard_max = 0;
 375         ret->fuzzy_max = dinfo->fuzzy_max;
 376         return ret;
 377 }
 378
 379 struct smatch_state *clone_estate_perm(struct smatch_state *state)
 380 {
 381         struct smatch_state *ret;
 382
 383         ret = malloc(sizeof(*ret));
 384         ret->name = alloc_string(state->name);
 385         ret->data = clone_dinfo_perm(get_dinfo(state));
 386         return ret;
 387 }
 388
 389