Techniques for Unreachable Code Detection

Below mentioned are the techniques for Unreachable Code Detection.

• Static Analysis Techniques
• Dynamic Analysis Techniques

Static Analysis Techniques

Static Analysis techniques analyze the program’s code or the intermediate outlined representation of code without actually executing it. Static Analysis helps to properly understand the control flow and the data flow of the survey program so that it will be easy to detect the potential Unreachable Code in the program.

• Control Flow Analysis: Control Flow Analysis measures the program’s control flow graph which traces all possible execution routes. Using the Code Flow Analysis we can identify the route that is not reached while executing the source program. Conditional Statements, Loops, Functional Calls, and branching constructs are taken into consideration in Control Flow Analysis.
• Data Flow Analysis: Data Flow Analysis traces variable values and their assignments throughout the program. The main purpose of using the Data Flow analysis is that it helps us to properly identify the variables that are just declared but not used in the source code. By analyzing the data dependencies, Data Flow analysis techniques easily detect dead code and also help to eliminate it from the code.

Dynamic Analysis Techniques

Dynamic Analysis Techniques are used to analyze the execution of the program with user testing inputs and tracking the test cases. The aim is to observe the behavior during the runtime execution of the program or source code. Dynamic Analysis Techniques detect the Unreachbele Code in the source program according to the execution route and Code Coverage data.

• Code Coverage Analysis: Code Code Analysis calculates the extent to which the program’s code is trained by a given set of test cases. Code Coverage Analysis identifies the code that is unexecuted in the source program execution. Some of the most used Common Code Coverage Metrics are Statement Coverage, Branch Coverage, and Path Coverage.
• Program Profiling: Program Profiling technique consists of collecting runtime data during program execution. This analysis of the execution tracks identifies the Code Routes that are never reached for execution. By Profiling the program’s behavior, Unreachable Code can be easily identified and subsequently eliminated.

Unreachable Code is also known as dead code in Compiler Design that points to the portion of a program that is never executed under any condition or scenario. This dead code doesn’t do any functionality in the program but unnecessarily occupies the space in the application memory, and also due to this there are different problems of unnecessary computation, that describe the program’s performance. So, to avoid this issue in Compiler Design, we can use the technique of Unreachable Code Elimination. In this Compiler Design article, we will see Unreachable Code Elimination with its techniques, practical examples, and advantages.