1.. _ContributingToLibcxx: 2 3====================== 4Contributing to libc++ 5====================== 6 7This file contains notes about various tasks and processes specific to contributing 8to libc++. If this is your first time contributing, please also read `this document 9<https://www.llvm.org/docs/Contributing.html>`__ on general rules for contributing to LLVM. 10 11For libc++, please make sure you follow `these instructions <https://www.llvm.org/docs/Phabricator.html#requesting-a-review-via-the-command-line>`_ 12for submitting a code review from the command-line using ``arc``, since we have some 13automation (e.g. CI) that depends on the review being submitted that way. 14 15Looking for pre-existing reviews 16================================ 17 18Before you start working on any feature, please take a look at the open reviews 19to avoid duplicating someone else's work. You can do that by going to the website 20where code reviews are held, `Differential <https://reviews.llvm.org/differential>`__, 21and clicking on ``Libc++ Open Reviews`` in the sidebar to the left. If you see 22that your feature is already being worked on, please consider chiming in instead 23of duplicating work! 24 25Pre-commit check list 26===================== 27 28Before committing or creating a review, please go through this check-list to make 29sure you don't forget anything: 30 31- Do you have tests for every public class and/or function you're adding or modifying? 32- Did you update the synopsis of the relevant headers? 33- Did you update the relevant files to track implementation status (in ``docs/Status/``)? 34- Did you mark all functions and type declarations with the :ref:`proper visibility macro <visibility-macros>`? 35- If you added a header: 36 37 - Did you add it to ``include/module.modulemap``? 38 - Did you add it to ``include/CMakeLists.txt``? 39 - If it's a public header, did you add a test under ``test/libcxx`` that the new header defines ``_LIBCPP_VERSION``? See ``test/libcxx/algorithms/version.pass.cpp`` for an example. NOTE: This should be automated. 40 - If it's a public header, did you update ``utils/generate_header_inclusion_tests.py``? 41 42- Did you add the relevant feature test macro(s) for your feature? Did you update the ``generate_feature_test_macro_components.py`` script with it? 43- Did you run the ``libcxx-generate-files`` target and verify its output? 44 45Post-release check list 46======================= 47 48After branching for an LLVM release: 49 501. Update ``_LIBCPP_VERSION`` in ``include/__config`` 512. Update the ``include/__libcpp_version`` file 523. Update the version number in ``docs/conf.py`` 53 54Exporting new symbols from the library 55====================================== 56 57When exporting new symbols from libc++, you must update the ABI lists located in ``lib/abi``. 58To test whether the lists are up-to-date, please run the target ``check-cxx-abilist``. 59To regenerate the lists, use the target ``generate-cxx-abilist``. 60The ABI lists must be updated for all supported platforms; currently Linux and 61Apple. If you don't have access to one of these platforms, you can download an 62updated list from the failed build at 63`Buildkite <https://buildkite.com/llvm-project/libcxx-ci>`__. 64Look for the failed build and select the ``artifacts`` tab. There, download the 65abilist for the platform, e.g.: 66 67* C++20 for the Linux platform. 68* MacOS C++20 for the Apple platform. 69