check_no_effect.c

   1 /*
   2  * sparse/check_no_effect.c
   3  *
   4  * Copyright (C) 2010 Dan Carpenter.
   5  *
   6  * Licensed under the Open Software License version 1.1
   7  *
   8  */
   9
  10 #include "smatch.h"
  11
  12 static int my_id;
  13
  14 static void match_stmt(struct statement *stmt)
  15 {
  16         struct expression *expr;
  17
  18         if (stmt->type != STMT_EXPRESSION)
  19                 return;
  20         expr = stmt->expression;
  21         if (!expr)
  22                 return;
  23         switch(expr->type) {
  24         case EXPR_PREOP:
  25                 if (expr->op == '!')
  26                         break;
  27                 if (expr->op == '~')
  28                         break;
  29         case EXPR_POSTOP:
  30         case EXPR_STATEMENT:
  31         case EXPR_ASSIGNMENT:
  32         case EXPR_CALL:
  33         case EXPR_CONDITIONAL:
  34         case EXPR_SELECT:
  35         case EXPR_CAST:
  36         case EXPR_FORCE_CAST:
  37         case EXPR_COMMA:
  38                 return;
  39         }
  40         if (in_expression_statement())
  41                 return;
  42         sm_msg("warn: statement has no effect %d", expr->type);
  43 }
  44
  45 void check_no_effect(int id)
  46 {
  47         my_id = id;
  48         add_hook(&match_stmt, STMT_HOOK);
  49 }