check_assign_vs_compare.c

   1 /*
   2  * Copyright (C) 2012 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
  20 static int my_id;
  21
  22 static void check_constant(struct expression *expr)
  23 {
  24         sval_t val;
  25
  26         if (!get_value(expr->right, &val))
  27                 return;
  28         sm_msg("warn: was '== %s' instead of '='", sval_to_str(val));
  29 }
  30
  31 static void check_address(struct expression *expr)
  32 {
  33         char *str;
  34         struct expression *right = strip_expr(expr->right);
  35
  36         if (!__cur_stmt || __cur_stmt->type != STMT_IF)
  37                 return;
  38
  39         if (right->type != EXPR_PREOP ||
  40             right->op != '&')
  41                 return;
  42
  43         if (get_macro_name(expr->pos))
  44                 return;
  45
  46         str = expr_to_str(right);
  47         sm_msg("warn: was '== %s' instead of '='", str);
  48         free_string(str);
  49 }
  50
  51 static void match_condition(struct expression *expr)
  52 {
  53         if (expr->type != EXPR_ASSIGNMENT || expr->op != '=')
  54                 return;
  55
  56         check_constant(expr);
  57         check_address(expr);
  58 }
  59
  60 void check_assign_vs_compare(int id)
  61 {
  62         my_id = id;
  63         add_hook(&match_condition, CONDITION_HOOK);
  64 }