c55c2ab806
Allow the main llvm-project repository to contain the buildbot builder instructions, instead of storing them in llvm-zorg. The corresponding llvm-zorg PR is https://github.com/llvm/llvm-zorg/pull/648. Using polly-x86_64-linux-test-suite as a proof-of-concept because that builder is currently offline, I am its maintainer, and is easier to build than an configuration supporting offload. Once the design has been decided, more builders can follow. Advantages are: * It is easier to make changes in the llvm-project repository. There are more reviewers than for the llvm-zorg repository. * Buildbot changes can be made in the same PR with changes that require updating the buildbot, e.g. changing the name of a CMake option. * Configuration changes take effect immeditately when landing; no buildbot master restart needed. * Some builders store a CMake cache file in the llvm-project repository for the reasons above. However, the number of changes that can be made with a CMake cache file alone are limited. Compared to AnnotatedBuilder, advantages are: * Reproducing a buildbot configuration locally made easy: just execute the script in-place. No llvm-zorg, local buildbot worker, or buildbot master needed. * Same for testing a change of a builder before landing it in llvm-zorg. Doing so with an AnnotatedBuilder requires two llvm-zorg checkouts: One for making the change of the builder script itself, which then is pushed to a private llvm-zorg branch on GitHub, and a second that is modified to fetch that branch instead of https://github.com/llvm/llvm-zorg/tree/main. * The AnnotatedBuilder scripts are located in the llvm-zorg repository and the buildbot-workers always checkout is always the top-of-trunk. This means that a buildbot configuration is split over three checkouts: * The checkout of llvm-project to be tested * The checkout of llvm-zorg by the buildbot-worker fetches; always the top-of-trunk, i.e may not match the revision of llvm-project that is executed (such as the CMake cache files located there), especially when using the "Force build" feature. * The checkout of llvm-zorg that the buildbot-master is running, which is updated only when the master is manually restarted. * The "Force Build" feature also allows for test-building any llvm-project PR. This is correctly handled by zorg's `addGetSourcecodeSteps`, but does not work with AnnotatedBuilders that checkout the llvm-project source on their own. The goal is to move as much as possible into the llvm-project repository such that there cannot be a mismatch between checkouts of different repositories. Ideally, the buildbot-master only needs to be updated+restarted for adding/removing workers, not for build configuration changes. --------- Co-authored-by: Jan Patrick Lehr <jp.lehr@gmail.com>
Polly - Polyhedral optimizations for LLVM ----------------------------------------- http://polly.llvm.org/ Polly uses a mathematical representation, the polyhedral model, to represent and transform loops and other control flow structures. Using an abstract representation it is possible to reason about transformations in a more general way and to use highly optimized linear programming libraries to figure out the optimal loop structure. These transformations can be used to do constant propagation through arrays, remove dead loop iterations, optimize loops for cache locality, optimize arrays, apply advanced automatic parallelization, drive vectorization, or they can be used to do software pipelining.