Code that is never executed is known as dead code. The presence of dead code often indicates that a logic error has occurred. Typically, this error is an a result of changes to the program or assumptions made by the program. Dead code is often optimized out of a program during compilation. However, to improve readability and ensure that logic errors are resolved dead code should be identified, understood, and removed from a program.
Non-Compliant Code Example
This example, inspired by Fortify demonstrates how dead code can be introduced into a program. The second conditional statement, if (s) may never evaluate true because it requires that s not be assigned NULL. However, the only path where s can be assigned a non-NULL value ends with a return statement.
int func(int condition) {
int *s = NULL;
if (condition) {
s = malloc(10);
if (s == NULL) {
/* Handle Error */
}
/* insert data into s */
return 0;
}
/* ... */
if (s) {
/* This code is never reached */
}
}