Code within a program 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 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. It requires that condition
be non-null, while on the only path where s
can be assigned a non-null value there is 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; } /* ... */ if (s) { /* This statement is never reached */ } }