What is Debugging : Types & Techniques in Embedded Systems

Every programmer in their life has a chance to experience bugs or errors in their code while developing an operating system or application or any other program. In such cases, developers use debugging and tools to find bugs in a code and make the code or program error-free. There is a chance to identify the bug and find where it has occurred in the entire program. In software technology, This is an important process to find bugs in any new program or any application process. Errors like fatal and logical errors can be found and removed to get the desired output. For example, GDB, Visual studio, and LLDB are the standard debuggers for different operating systems.

What is Debugging?

Definition: The important technique to find and remove the number of errors or bugs or defects in a program is called Debugging. It is a multistep process in software development. It involves identifying the bug, finding the source of the bug and correcting the problem to make the program error-free. In software development, the developer can locate the code error in the program and remove it using this process.  Hence, it plays a vital role in the entire software development lifecycle.

Types of Debugging

Depending upon the type of code error, there are different types of toolset plugins. It is necessary to understand what is happening and what type of tool is used for debugging. There are two types of debugging to solve any general issue of the toolset plugin and provides technical information.

• In PHP, the PHP code can be debugged to attach a debugger client using any one of these tools. Debug utilities like Xdebug and Zendbugger are used to work with PHPstorm. Kint is used as a debugging tool for PHP debugging.

For example, to enable the PHP debugging in WordPress, edit the file wp-config.php and add the code needed. An error file (error_log.txt) is produced in the word root dictionary which can be created and writable using a sever web. Else use an FTP program to create and write. Hence all the errors that occurred in the front-end and back-end can be logged into that error file.

• Javascript debugging uses the browser’s debugger tool and javascript console. Any javascript error can be occurred and stops the execution and functioning of the operations in WordPress. When the javascript console is open, all the error messages will be cleared. However, some console warnings appeared can create an error message that should be fixed.

There are different types of debugging for different operating systems. They are,

• For Linux and Unix operating systems, GDB is used as a standard debugger.
• For Windows OS, the visual studio is a powerful editor and debugger.
• For Mac OS, LLDB is a high-level debugger.
• Intel parallel inspector is used as a source of debugging for memory errors in C/C++ operations.

Debugging Process

The process of finding bugs or errors and fixing them in any application or software is called debugging. To make the software programs or products bug-free, this process should be done before releasing them into the market. The steps involved in this process are,

• Identifying the error – It saves time and avoids the errors at the user site. Identifying errors at an earlier stage helps to minimize the number of errors and wastage of time.
• Identifying the error location – The exact location of the error should be found to fix the bug faster and execute the code.
• Analyzing the error – To understand the type of bug or error and reduce the number of errors we need to analyze the error. Solving one bug may lead to another bug that stops the application process.
• Prove the analysis – Once the error has been analyzed, we need to prove the analysis. It uses a test automation process to write the test cases through the test framework.
• Cover the lateral damage – The bugs can be resolved by making the appropriate changes and move onto the next stages of the code or programs to fix the other errors.
• Fix and Validate – This is the final stage to check all the new errors, changes in the software or program and executes the application.

Debugging Software

This software plays a vital role in the software development process. Software developers use it to find the bugs, analyze the bugs and enhance the quality and performance of the software. The process of resolving the bugs using manual debugging is very tough and time-consuming. We need to understand the program, it’s working, and the causes of errors by creating breakpoints.

As soon as the code is written, the code is combined with other stages of programming to form a new software product. Several strategies like unit tests, code reviews, and pair programming are used to debug the large program (contains thousands of lines of code). The standard debugger tool or the debug mode of the Integral Development Environment (IDE) helps determine the code’s logging and error messages.

The steps involved in debugging software are,

• The bug is identified in a system and defect report is created. This report helps the developer to analyze the error and find the solutions.
• The debugging tool is used to know the cause of the bug and analyze it by step-by-step execution process.
• After identifying the bug, we need to make the appropriate changes to fix the issues.
• The software is retested to ensure that no error is left and checks all the new errors in the software during the debugging software process.
• A sequence-based method used in this software process made it easier and more convenient for the developer to find the bugs and fix them using the code sequences.

Debugging Techniques

To perform the debugging process easily and efficiently, it is necessary to follow some techniques. The most commonly used debugging strategies are,

• Debugging by brute force
• Induction strategy
• Deduction strategy
• Backtracking strategy and
• Debugging by testing.

Debugging by brute force is the most commonly used technique. This is done by taking memory dumps of the program which contains a large amount of information with intermediate values and analyzing them, but analyzing the information and finding the bugs leads to a waste of time and effort.

Induction strategy includes the Location of relevant data, the Organization of data, the Devising hypothesis (provides possible causes of errors), and the Proving hypothesis.

Deduction strategy includes Identification of possible causes of bugs or hypothesis Elimination of possible causes using the information Refining of the hypothesis( analyzing one-by-one)

The backtracking strategy is used to locate errors in small programs. When an error occurs, the program is traced one step backward during the evaluation of values to find the cause of bug or error.

Debugging by testing is the conjunction with debugging by induction and debugging by deduction technique. The test cases used in debugging are different from the test cases used in the testing process.

Debugging Techniques in Embedded Systems

These techniques reduce the error count and increase the quality and functionality of the code. Debugging of the embedded systems depends on physical memory addresses and virtual memory.

There are 6 debugging techniques in an embedded system.

• Simplify the complex data
• Divide and conquer
• Slow down the process
• Change only one variable at a time
• Creating off-line models
• start from a known-good state.

Different debugging techniques are used in different cases. A combination of one or more approaches may cause errors. This process includes

• Reproduce the bug or problem
• Explain the bug using input from the user
• Try to get all the variable values and state of the program when the bug appears
• Analyze the bug and find the cause of the bug
• Fix the bug and check all the causes of new bugs.

Debugging Tools

A software tool or program used to test and debug the other programs is called a debugger or a debugging tool. It helps to identify the errors of the code at the various stages of the software development process. These tools analyze the test run and find the lines of codes that are not executed. Simulators in other debugging tools allow the user to know about the display and behavior of the operating system or any other computing device. Most of the open-source tools and scripting languages don’t run an IDE and they require the manual process.

Mostly used Debugging Tools are GDB, DDD, and Eclipse.

• GDB  Tool: This type of tool is used in Unix programming. GDB is pre-installed in all Linux systems if not, it is necessary to download the GCC compiler package.
• DDD  Tool: DDD means Data Display Debugger, which is used to run a Graphic User Interface (GUI) in Unix systems.
• Eclipse: An IDE  tool is the integration of an editor, build tool, debugger and other development tools. IDE is the most popular Eclipse  tool. It works more efficiently when compared to the DDD, GDB and other tools.

The list of debugging tools is listed below.

• AppPuncher Debugger is used for debugging Rich Internet Applications
• AQtime debugger
• CA/EZ TEST is a CICS interactive test/debug software package
• CharmDebug is a Debugger for Charm++
• CodeView debugger
• DBG is a PHP Debugger and Profiler
• dbx debugger
• Distributed Debugging Tool (Allinea DDT)
• DDTLite — Allinea DDTLite for Visual Studio 2008
• DEBUG is the built-in debugger of DOS and Microsoft Windows
• Debugger for MySQL
• Opera Dragonfly
• The dynamic debugging technique (DDT)
• Embedded System Debug Plug-in is used for Eclipse
• FusionDebug
• Debugger OpenGL, OpenGL ES, and OpenCL Debugger and Profiler. For Windows, Linux, Mac OS X, and iPhone
• GNU Debugger (GDB), GNU Binutils
• Intel Debugger (IDB)
• The system is used as circuit debugger for Embedded Systems
• Interactive Disassembler (IDA Pro)
• Java Platform Debugger Architecture source Java debugger
• LLDB
• MacsBug
• IBM Rational Purify
• TRACE32 is circuit debugger for Embedded Systems
• VB Watch Debugger — debugger for Visual Basic 6.0
• Microsoft Visual Studio Debugger
• WinDbg
• Xdebug — PHP debugger and profiler

Thus, this is all about the debugging process, its tools, and techniques in embedded systems Software development processes. The purpose of this is to find and remove the bugs in any code. Here is a question for you, what are the disadvantages of debugging?