check_min_t.c

   1 /*
   2  * Copyright (C) 2011 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 #include "smatch.h"
  19
  20 static int my_id;
  21
  22 static void match_assign(struct expression *expr)
  23 {
  24         const char *macro;
  25         sval_t max_left, max_right;
  26         char *name;
  27
  28         if (expr->op != '=')
  29                 return;
  30
  31         macro = get_macro_name(expr->pos);
  32         if (!macro)
  33                 return;
  34         if (strcmp(macro, "min_t"))
  35                 return;
  36
  37         if (!get_absolute_max(expr->left, &max_left))
  38                 return;
  39         if (!get_absolute_max(expr->right, &max_right))
  40                 return;
  41
  42         if (sval_cmp(max_left, max_right) >= 0)
  43                 return;
  44
  45         name = expr_to_str(expr->right);
  46         sm_msg("warn: min_t truncates here '%s' (%s vs %s)", name, sval_to_str(max_left), sval_to_str(max_right));
  47         free_string(name);
  48 }
  49
  50 void check_min_t(int id)
  51 {
  52         my_id = id;
  53         if (option_project != PROJ_KERNEL)
  54                 return;
  55         add_hook(&match_assign, ASSIGNMENT_HOOK);
  56 }