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 void match_stmt(struct statement *stmt)
  23 {
  24         struct expression *expr;
  25
  26         if (stmt->type != STMT_EXPRESSION)
  27                 return;
  28         expr = stmt->expression;
  29         if (!expr)
  30                 return;
  31         switch(expr->type) {
  32         case EXPR_PREOP:
  33                 if (expr->op == '!')
  34                         break;
  35                 if (expr->op == '~')
  36                         break;
  37         case EXPR_POSTOP:
  38         case EXPR_STATEMENT:
  39         case EXPR_ASSIGNMENT:
  40         case EXPR_CALL:
  41         case EXPR_CONDITIONAL:
  42         case EXPR_SELECT:
  43         case EXPR_CAST:
  44         case EXPR_FORCE_CAST:
  45         case EXPR_COMMA:
  46                 return;
  47         }
  48         if (in_expression_statement())
  49                 return;
  50         sm_msg("warn: statement has no effect %d", expr->type);
  51 }
  52
  53 void check_no_effect(int id)
  54 {
  55         my_id = id;
  56         add_hook(&match_stmt, STMT_HOOK);
  57 }