How To Contribute

We welcome bug reports, fixes, tests, documentation, and feature proposals.

Before You Start

Always start by creating a GitHub Issues. You can use these to report bugs and to discuss related fixes, suggest new tests, improvements to documentation, and to discuss feature proposals before implementation.

Change Process

• Contributors and AI tools MUST preserve existing changes and modify only files needed for the task.

• Add or update tests for behavior changes. If no test is added, explain why in the pull request and identify applicable existing coverage.

• Submit all changes through a pull request.

• Format changed C and C++ files with clang-format-21 --style=file -i <file> before submitting.

• Run clang-tidy-diff.py with .clang-tidy before submitting to report clang-tidy diagnostics only on changed C and C++ lines.

• Run tests relevant to the change. See unit tests and WAMR test suites for commands and supported configurations.

Code Guidelines

• Keep changes minimal. Reuse existing mechanisms, functions, and variables when they meet the need.

• Keep each pull request focused and approximately 300--400 changed lines. Split larger changes into reviewable pull requests. AI will be good at splitting large changes into smaller ones, but humans should review the split for correctness and completeness.

• Submit formatting-only and refactoring-only changes in separate pull requests.

• Prefer platform-specific source directories over platform-selection macros.

• Log every error branch with actionable context.

• Use return values to propagate errors.

Task-Specific Requirements

New Features

• Add a compilation option in build-scripts/config_common.cmake. Default it to 0 unless the feature must be enabled by default.

• Add the corresponding macro switch in core/config.h. Default it to 0 unless the feature must be enabled by default.

• Update doc/build_wamr.md with the option and its usage.

• Add or update a demonstration in samples.

LLVM Upgrades

• Update build-scripts/build_llvm.py.

• Update .github/workflows/build_llvm_libraries.yml as needed for the new LLVM version.

• Verify the AOT LLVM JIT spec tests pass.

• Verify CI can use the upgraded LLVM libraries and passes.

• Verify features highly dependent on LLVM (e.g., PGO, LTO) work as expected.

Pull Request Checklist

• The pull request describes the problem, solution, and validation performed.

• Changed code is formatted and relevant tests pass.

• Documentation is updated when user-visible behavior, configuration, or APIs change.

![TIPS] Unfinished, waiting for more

License

WAMR is licensed under Apache-2.0 with the LLVM exception. Contributions are submitted under the same license. See LICENSE.

Code of Conduct

Follow the Code of Conduct.