| .. _ContributingToLibcxx: |
| |
| ====================== |
| Contributing to libc++ |
| ====================== |
| |
| .. contents:: |
| :local: |
| |
| Please read `this document <https://www.llvm.org/docs/Contributing.html>`__ on general rules to contribute to LLVM projects. |
| |
| Tasks and processes |
| =================== |
| |
| This file contains notes about various tasks and processes specific to libc++. |
| |
| Looking for pre-existing reviews |
| ================================ |
| |
| Before you start working on any feature, please take a look at the open reviews |
| to avoid duplicating someone else's work. You can do that by going to the website |
| where code reviews are held, `Differential <https://reviews.llvm.org/differential>`__, |
| and clicking on ``Libc++ Open Reviews`` in the sidebar to the left. If you see |
| that your feature is already being worked on, please consider chiming in instead |
| of duplicating work! |
| |
| Post-Release TODO |
| ================= |
| |
| After branching for an LLVM release: |
| |
| 1. Update ``_LIBCPP_VERSION`` in ``include/__config`` |
| 2. Update the ``include/__libcpp_version`` file |
| 3. Update the version number in ``docs/conf.py`` |
| |
| Modifying feature-test macros |
| ============================= |
| |
| When adding or updating feature-test macros, you should update the corresponding tests. |
| To do that, modify ``feature_test_macros`` table in the script |
| ``utils/generate_feature_test_macro_components.py``, run it, and commit updated |
| files. Running ``utils/generate_feature_test_macro_components.py`` should never |
| generate diffs in a clean checkout; feel free to run it in your local checkout |
| any time you want. |
| |
| |
| Adding a new header TODO |
| ======================== |
| |
| When adding a new header to libc++: |
| |
| 1. Add a test under ``test/libcxx`` that the new header defines ``_LIBCPP_VERSION``. See ``test/libcxx/algorithms/version.pass.cpp`` for an example. |
| 2. Run ``python utils/generate_header_tests.py``; verify and commit the changes. |
| 3. Modify ``python utils/generate_header_inclusion_tests.py``; run it; verify and commit the changes. |
| 4. Create a submodule in ``include/module.modulemap`` for the new header. |
| 5. Update the ``include/CMakeLists.txt`` file to include the new header. |
| |
| Exporting new symbols from the library |
| ====================================== |
| |
| When exporting new symbols from libc++, you must update the ABI lists located in ``lib/abi``. |
| To test whether the lists are up-to-date, please run the target ``check-cxx-abilist``. |
| To regenerate the lists, use the target ``generate-cxx-abilist``. |
| The ABI lists must be updated for all supported platforms; currently Linux and |
| Apple. If you don't have access to one of these platforms, you can download an |
| updated list from the failed build at |
| `Buildkite <https://buildkite.com/llvm-project/libcxx-ci>`__. |
| Look for the failed build and select the ``artifacts`` tab. There, download the |
| abilist for the platform, e.g.: |
| |
| * C++20 for the Linux platform. |
| * MacOS C++20 for the Apple platform. |