ObjectLayoutInspector enables runtime inspection of CLR type layouts, providing details about field offsets and sizes. The library employs the LdFlda instruction to dynamically determine the addresses of fields within an object instance. This tool addresses the challenge of accessing field layout information, which is not directly exposed through the C# language, offering a workaround using code generation.
The project uses a clever approach of generating dynamic methods with LdFlda instructions to circumvent the lack of direct access to field offsets in C#. It handles value types and reference types, including those without default constructors, using CreateInstance and GetUninitializedObject. The implementation provides precise field offset calculation and struct size determination, enhancing its value for performance analysis and understanding memory layout.
- Field Offset Determination: Precisely calculates the offsets of fields within a given type at runtime.
- Struct Size Calculation: Determines the size of value types (structs) by observing the layout of generated instances.
- Handles No Default Constructor: Uses
FormatterServices.GetUninitializedObjectto handle classes without default constructors. - x64 Target: Currently supports x64 (64-bit) runtime environments.
- Code Generation: Employs dynamic method generation with
LdFldainstructions to inspect field locations.
The project is actively developed and maintained, with recent commits indicating ongoing improvements and bug fixes. The documentation provides clear examples and explanations of the core concepts and usage scenarios. While the current version supports only x64 platforms, the implementation is designed for potential future expansion to other architectures. The active community and frequent updates suggest a reliable and evolving tool.
ObjectLayoutInspector benefits developers needing detailed insight into type structures for performance optimization or debugging. It's particularly useful for understanding memory layout, identifying potential performance bottlenecks related to data alignment, and ensuring efficient use of memory. It offers a valuable alternative to tedious manual inspection methods like using SOS Debugging Extension or raw memory examination.