View source for LDC contributor's guide

This page is a work-in-progress collection of tips for LDC contributors and development guidelines.

== Continuous Integration ==
The LDC project uses two different CI systems: [https://travis-ci.org/ldc-developers/ldc Travis CI], which is Ubuntu x86 only but also tests pull requests, and [http://ci.lycus.org/job/LDC/ ci.lycus.org], which has three different x86_64 Linux slaves.

Any efforts to get regular builds running on Windows and OS X would be very much appreciated.

To run the test suite locally, use ''ctest'' (e.g. <tt>ctest -j3 --output-on-failure</tt>) in the CMake root directory. To work on a specific test case, you might want to look into the <tt>-R</tt> and <tt>--verbose</tt> options to ''ctest''.

== Style guidelines ==
Generally, use your good taste and try to use a style similar to the surrounding code. Many parts of the [http://llvm.org/docs/CodingStandards.html LLVM Coding Standards] are directly applicable to LDC as well.

=== Formatting, etc. ===
* Hard rules: 4 spaces for indentation, LF newlines.
* Use include guards consistently, in the format ''LDC_<dir>_<filename>'', e.g. ''LDC_GEN_DVALUE_H''.
* Includes are placed at the top of the file, sorted lexicographically and grouped in the following order:
*# Main include corresponding to the .cpp file, if any.
*# DMD and other LDC includes.
*# LLVM/libconfig includes.
*# System includes.

=== APIs and idioms ===
* Avoid making changes to the front end sources (''dmd'' and ''dmd2'') as much as reasonably possible. If modifications are necessary, be sure to enclose the deviations from the upstream source <tt>#if IN_LLVM</tt> blocks, and keep the original source code around for easier comparison. This makes it much easier to resolve any merge conflicts when folding in new frontend releases.
* Use [http://llvm.org/docs/doxygen/html/ErrorHandling_8h.html#ace243f5c25697a1107cce46626b3dc94 ''llvm_unreachable("message")''] instead of ''assert(0 && "message")'' (from ''llvm/Support/ErrorHandling.h''). Not only might it lead to slightly better codegen, it also prevents »variable might be used uninitialized« and similar compiler warnings.

== Updating the dmd-testsuite repository ==

The [https://github.com/ldc-developers/dmd-testsuite dmd-testsuite] repository is derived from the upstream DMD repository by the [https://github.com/ldc-developers/ldc-scripts/blob/master/dmd-testsuite/update-dmd-testsuite.sh update-dmd-testsuite.sh] script in the [https://github.com/ldc-developers/ldc-scripts ldc-scripts] repository. Just run it without arguments, and it should update the repository with the latest commits/tags (given that you have Git installed and an SSH key configured for github.com). The changes should apply to the remote repository in a fast-forward fashion, never force a push.

After this is done, when merging a new DMD frontend release, just merge the ''v2.<xyz>'' tag into the ''ldc'' branch, manually resolving any merge conflicts as necessary (most changes should definitely be upstreamed).

[[Category:LDC]]