check_do_while_loop_limit.c

   1 /*
   2  * Copyright (C) 2021 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_slist.h"
  20 #include "smatch_extra.h"
  21
  22 static int my_id;
  23
  24 STATE(post_minus);
  25
  26 static bool is_post_minus(struct expression *expr)
  27 {
  28         expr = strip_expr(expr);
  29         if (!expr)
  30                 return false;
  31         if (expr->type != EXPR_POSTOP)
  32                 return false;
  33         if (expr->op != SPECIAL_DECREMENT)
  34                 return false;
  35         return true;
  36 }
  37
  38 static void match_post_loop(struct expression *expr)
  39 {
  40         struct statement *stmt;
  41
  42         expr = strip_expr(expr);
  43         stmt = expr_get_parent_stmt(expr);
  44
  45         if (!stmt)
  46                 return;
  47         if (stmt->type != STMT_ITERATOR)
  48                 return;
  49         if (!is_post_minus(stmt->iterator_post_condition))
  50                 return;
  51         if (is_post_minus(stmt->iterator_post_condition))
  52                 set_state_expr(my_id, stmt->iterator_post_condition->left, &post_minus);
  53 }
  54
  55 static void match_condition(struct expression *expr)
  56 {
  57         if (get_state_expr(my_id, expr) != &post_minus)
  58                 return;
  59         sm_warning("do while ends on '%s == -1'", expr_to_str(expr));
  60 }
  61
  62 void check_do_while_loop_limit(int id)
  63 {
  64         my_id = id;
  65         add_hook(&match_post_loop, CONDITION_HOOK);
  66         add_hook(&match_condition, CONDITION_HOOK);
  67 }