check_no_effect.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 #include "smatch.h"
  19
  20 static int my_id;
  21
  22 static struct string_list *ignored_macros;
  23
  24 static bool in_ignored_macro(struct expression *expr)
  25 {
  26         char *macro;
  27
  28         macro = get_macro_name(expr->pos);
  29         if (!macro)
  30                 return false;
  31         return list_has_string(ignored_macros, macro);
  32 }
  33
  34 static void match_stmt(struct statement *stmt)
  35 {
  36         struct expression *expr;
  37
  38         if (stmt->type != STMT_EXPRESSION)
  39                 return;
  40         expr = stmt->expression;
  41         if (!expr)
  42                 return;
  43         switch(expr->type) {
  44         case EXPR_PREOP:
  45                 if (expr->op == '!')
  46                         break;
  47                 if (expr->op == '~')
  48                         break;
  49         case EXPR_POSTOP:
  50         case EXPR_STATEMENT:
  51         case EXPR_ASSIGNMENT:
  52         case EXPR_CALL:
  53         case EXPR_CONDITIONAL:
  54         case EXPR_SELECT:
  55         case EXPR_CAST:
  56         case EXPR_FORCE_CAST:
  57         case EXPR_COMMA:
  58                 return;
  59         }
  60         if (in_expression_statement())
  61                 return;
  62         if (in_ignored_macro(expr))
  63                 return;
  64         sm_warning("statement has no effect %d", expr->type);
  65 }
  66
  67 void check_no_effect(int id)
  68 {
  69         my_id = id;
  70         add_hook(&match_stmt, STMT_HOOK);
  71         ignored_macros = load_strings_from_file(option_project_str, "ignore_no_effect");
  72 }