LLDB vs Xdebug

LLDB is a free debugger built from reusable components that use LLVM libraries, including Clang's expression parser and the LLVM disassembler. It is the default debugger in Xcode on macOS and supports debugging C, C++, and Objective-C on desktop and iOS devices and simulators. Its tools include breakpoints, watchpoints, process launching, and attaching to programs; remote debugging is also documented for Linux, Windows, Android, and iOS. Expression evaluation uses Clang infrastructure for current C-family language features, multiline expressions, and just-in-time evaluation where supported. Developers can use its shared-library C++ API and Python bindings for scripting, symbolication, disassembly, and inspecting object and symbol files. The lldb-dap adapter connects LLDB functionality to compatible editors and IDEs, including Visual Studio Code, Emacs, vim, and neovim. LLDB is available under the Apache 2.0 License with LLVM exceptions. Windows support remains under active development, with ARM and AArch64 described as more experimental. The lldb-dap interface documents no support for step-back, setting a variable, goto-target, or terminate requests.

Xdebug is a PHP extension that adds debugging and analysis features to PHP development. Its step debugger lets developers move through code interactively to examine control flow and data structures. It improves var_dump() output and adds stack traces for notices, warnings, errors, and exceptions. Function tracing can record calls, arguments, and invocation locations, with optional variable assignments and return values. The profiler reports execution and memory use in Cachegrind-compatible files, while code coverage can show what runs during PHPUnit tests. Xdebug communicates with IDEs through DBGp, a protocol supported by nearly every PHP IDE, including Visual Studio Code and PhpStorm. Installation instructions cover Linux, macOS, Windows, and Unix-like systems, with compatibility information organized by PHP version. Xdebug itself is free. Paid Pro costs £200 per year for one developer; Business costs £1,000 per year for 2–20 developers. Both paid tiers include email technical support. Xdebug Cloud is described as a relay for situations where a network or firewall blocks direct debugger connections.