LLDB: A Comprehensive Guide to Debugging

 

CodeLLDB - Visual Studio Marketplace

Extension for Visual Studio Code - A native debugger powered by LLDB. Debug C++, Rust and other compiled languages.

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CodeLLDB:
CodeLLDB is a powerful and flexible debugger extension for Visual Studio Code. It provides advanced debugging features for C, C++, and Rust applications.

LLDB Commands

Start Debugging a Program:

lldb <program>

Run the Program:

run

Set a Breakpoint:

breakpoint set --name <function_name>

Sets a breakpoint at the specified function.

Set a Breakpoint at a Specific Line:

breakpoint set --file <filename> --line <line_number>

Sets a breakpoint at a specific line in a file.

Set Conditional Breakpoints:

breakpoint set --name <function_name> --condition "<condition>"

Sets a breakpoint that only triggers when the condition is true.

List Breakpoints:

breakpoint list

Displays all breakpoints.

Step Over a Line:

next

Executes the next line of code but steps over function calls.

Step Into a Function:

step

Steps into a function if the current line calls one.

Continue Execution:

continue

Inspect Variables:

frame variable <variable_name>

Displays the value of a variable in the current scope.

Watch a Variable:

watchpoint set variable <variable_name>

Sets a watchpoint to monitor changes to a variable.

Inspect Call Stack:

thread backtrace

Displays the call stack of the current thread.

Inspect Memory:

memory read <address> --size <size>

Reads memory from the specified address.

Examine Memory:

memory read <address> --size <size> --format <format>

Reads the memory at a specific address. You can specify the size (--size) and format (--format, e.g., x for hexadecimal).

Dump Memory in Hexadecimal:

memory read <address> --size <size> --format x

Dumps memory in a hexadecimal format for easier inspection.

View Registers:

register read

Displays the values of all CPU registers.

Change Register Values:

register write <register_name> <value>

Modifies the value of a register.

List Disassembled Code:

disassemble --frame

Disassembles the current function’s code.

Disassemble a Specific Function:

disassemble --name <function_name>

Disassembles a specific function by name.

Evaluate Expressions:

expression <expression>

Evaluates an expression and print the result.

Additional Resources

1. LLDB Tutorial
2. GDB to LLDB command map