LLDB Commands Tutorial

Introduction to LLDB

LLDB is a powerful debugger that is part of the LLVM project. It provides developers with a variety of commands to inspect and control the execution of programs. This tutorial focuses on LLDB commands specifically for debugging Swift applications.

Getting Started with LLDB

To start using LLDB, you typically launch it from the terminal or through Xcode. If you are running it from the command line, you can start your Swift program with LLDB using the following command:

Replace path/to/your_program with the actual path to your compiled Swift executable.

Basic LLDB Commands

Here are some fundamental LLDB commands that you will find useful:

• breakpoint set: Set a breakpoint at a specified line or function.
• run: Start the execution of the program.
• next: Move to the next line of code, stepping over function calls.
• step: Step into the function calls, allowing you to debug deeper.
• continue: Resume execution until the next breakpoint is hit.
• print: Display the value of a variable.

Setting Breakpoints

To set a breakpoint on a specific line, use the following command:

This command sets a breakpoint at line 10 of MyFile.swift. When the program reaches this line, it will pause execution, allowing you to inspect the current state.

Running the Program

To start executing the program, use the run command:

Once the program hits a breakpoint, you can use other commands to inspect variables or step through the code.

Inspecting Variables

To check the value of a variable, use the print command:

This will display the current value of myVariable in the console.

Stepping Through Code

When you want to execute the next line of code, you can use:

If you want to step into a function to debug its execution, use:

Continuing Execution

To continue running the program until it hits the next breakpoint, type:

Exiting LLDB

To exit LLDB, simply type:

You can also use exit for the same effect.

Conclusion

LLDB provides a rich set of commands that can significantly aid in debugging Swift applications. By mastering these commands, you can identify and resolve issues in your code more efficiently. Experiment with these commands in your own projects to become more proficient in debugging with LLDB.