smatch_impossible.c

   1 /*
   2  * Copyright (C) 2014 Oracle.
   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 #include "smatch.h"
  19 #include "smatch_extra.h"
  20
  21 static int my_id;
  22
  23 STATE(impossible);
  24
  25 int is_impossible_path(void)
  26 {
  27         if (get_state(my_id, "impossible", NULL) == &impossible)
  28                 return 1;
  29         return 0;
  30 }
  31
  32 static void handle_compare(struct expression *left, int op, struct expression *right)
  33 {
  34         if (!possibly_true(left, op, right))
  35                 set_true_false_states(my_id, "impossible", NULL, &impossible, NULL);
  36         if (!possibly_false(left, op, right))
  37                 set_true_false_states(my_id, "impossible", NULL, NULL, &impossible);
  38
  39 }
  40
  41 static void match_condition(struct expression *expr)
  42 {
  43         if (expr->type == EXPR_COMPARE)
  44                 handle_compare(expr->left, expr->op, expr->right);
  45         else
  46                 handle_compare(expr, SPECIAL_NOTEQUAL, zero_expr());
  47 }
  48
  49 void register_impossible(int id)
  50 {
  51         my_id = id;
  52
  53         add_hook(&match_condition, CONDITION_HOOK);
  54 }
  55
  56