🦈 IMP: LLVM 20, Minor Assembly Optimizations, MantaRay 2, Python Bindings

[TheBlackPlague]

🎯 Summary

This PR does the following:

• Upgrade to C++23. Furthermore, specific style changes are made to ensure modern-day code with respect to LLVM 20.
• Upgrade to LLVM 20 concerning action workflows and documentation, as it provides better support for C++23.
• Upgrade to MantaRay 2 (currently under development).
• MantaRay 2 relying on CMake V3.21 requires StockDory's minimum CMake version to increase to 3.21.
• Removes redundant zeroing stack operations that can be avoided when allocating the move list.
• Removes inline decorative from most places and resolves to rely on compiler inlining choices. In some instances, guaranteed inlining is still wanted, and in those situations, [[clang::always_inline]] is used.
• Switch to Nanothread for the backing Thread Pool Library and encapsulate it in a C++ Thread Pool class.

All of the above lead to considerable performance improvements.

In addition, StockDory now provides Python Bindings as an ease-of-use addition. These Python Bindings are largely unfinished in their current state and will be subject to change until engine version 1.0, but they should help those interested in using the engine from Python. Performance issues will be monitored.

As a side note, workflows are refactored into more modern versions and support mainstream Apple Desktop chips.

👏 Acknowledgements

NA

📈 ELO

STC:

Elo   | 6.01 +- 4.18 (95%)
SPRT  | 10.0+0.10s Threads=1 Hash=16MB
LLR   | 2.95 (-2.94, 2.94) [0.00, 5.00]
Games | N: 9304 W: 2474 L: 2313 D: 4517
Penta | [119, 1058, 2155, 1183, 137]

LTC:

Elo   | 9.90 +- 5.45 (95%)
SPRT  | 60.0+0.60s Threads=1 Hash=128MB
LLR   | 2.96 (-2.94, 2.94) [0.00, 5.00]
Games | N: 4494 W: 1117 L: 989 D: 2388
Penta | [24, 482, 1114, 596, 31]

[Copilot]

Pull Request Overview

This PR updates the codebase to support Python bindings while upgrading the LLVM requirement to version 20. Key changes include refactoring the AttackTable namespace and static data definitions, modernizing the Board class implementation with newer C++ features and improved castling logic, and updating build scripts and CI workflows for better cross‐platform support and PGO builds.

Reviewed Changes

Copilot reviewed 55 out of 65 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/Backend/Move/AttackTable.h	Refactored namespace and removed unused includes and code sections.
src/Backend/Misc.h	Added a utility function for hexadecimal conversion.
src/Backend/Board.h	Modernized constructors and methods, updated castling and move logic.
pyproject.toml	Introduced configuration for Python bindings using Pybind11.
README.md	Updated LLVM version requirement and minor documentation tweaks.
Makefile	Enhanced build targets with improved profiling and cross-platform flags.
Information.cmake	Updated author string for consistency.
CMakeLists.txt	Revised C++ standard and options to support Python module building.
.github/workflows/*.yml	Updated workflows to use Clang 20 and expanded build matrix configurations.

Files not reviewed (10)

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• .idea/fileTemplates/internal/C Header File.h: Language not supported
• .idea/fileTemplates/internal/C++ Class Header.h: Language not supported
• .idea/inspectionProfiles/Project_Default.xml: Language not supported
• .idea/misc.xml: Language not supported
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Comments suppressed due to low confidence (1)

src/Backend/Board.h:128

• [nitpick] The debug output to std::cout may be inappropriate in production; consider removing it or replacing it with a proper error logging mechanism or assertion.

if (piece == NAP) std::cout << "ERROR" << std::endl;