NOTE: THIS DOCUMENT IS A WORK IN PROGRESS!
This document collects information about successfully releasing LLVM to the public. It is the release manager's guide to ensuring that a high quality build of LLVM is released. Mostly, it's just a bunch of reminders of things to do at release time so we don't inadvertently ship something that is utility deficient.
There are three main tasks for building a release of LLVM:
Review the documentation and ensure that it is up to date. The Release Notes must be updated to reflect bug fixes, new known issues, and changes in the list of supported platforms. The Getting Started Guide should be updated to reflect the new release version number tag avaiable from CVS and changes in basic system requirements.
Merge any work done on branches intended for release into mainline. Finish and commit all new features or bug fixes that are scheduled to go into the release. Work that is not to be incorporated into the release should not be merged from branchs or commited from developer's working directories.
From this point until the release branch is created, developers should not commit changes to the llvm and llvm-gcc CVS repositories unless it is a bug fix for the release.
Rebuild the LibDeps.txt target in utils/llvm-config. This makes sure that the llvm-config utility remains relevant for the release, reflecting any changes in the library dependencies.
Use the nightly test reports and 'make check' (deja-gnu based tests) to ensure that recent changes and merged branches have not destabilized LLVM. Platforms which are used less often should be given special attention as they are the most likely to break from commits from the previous step.
Tag and branch the CVS HEAD using the following procedure:
cvs tag ROOT_RELEASE_XX
cvs tag -b -r ROOT_RELEASE_XX release_XX
cvs -d <CVS Repository> co -r release_XX llvm
cvs -d <CVS Repository> co -r release_XX llvm-test
cvs -d <CVS Repository> co -r release_XX llvm-gcc
After creating the llvm release branch, update the release branch's autoconf/configure.ac version from X.Xcvs to just X.X. Update it on mainline as well to be the next version (X.X+1cvs).
Build both debug and release (optimized) versions of LLVM on all platforms. Ensure the build is warning and error free on each platform.
Build a new version of the LLVM GCC front-end after building the LLVM tools. Once that is complete, go back to the LLVM source tree and build and install the llvm/runtime libraries.
Run make check and ensure there are no unexpected failures. If there are, resolve the failures, commit them back into the release branch, and restart testing by re-building LLVM.
Ensure that 'make check' passes on all platforms for all targets. If certain failures cannot be resolved before release time, determine if marking them XFAIL is appropriate. If not, fix the bug and go back. The test suite must complete with "0 unexpected failures" for release.
Run the llvm-test suite and ensure there are no unacceptable failures. If there are, resolve the failures and go back to re-building LLVM. The test suite should be run in Nightly Test mode. All tests must pass.
Create source distributions for LLVM, LLVM GCC, and the LLVM Test Suite by exporting the source from CVS and archiving it. This can be done with the following commands:
cvs -d <CVS Repository> export -r release_XX llvm
cvs -d <CVS Repository> export -r release_XX llvm-test
cvs -d <CVS Repository> export -r release_XX llvm-gcc
mkdir cfrontend; mv llvm-gcc cfrontend/src
tar -cvf - llvm | gzip > llvm-X.X.tar.gz
tar -cvf - llvm-test | gzip > llvm-test-X.X.tar.gz
tar -cvf - cfrontend/src | gzip > cfrontend-X.X.source.tar.gz
You can, optionally, create source and binary RPM packages for LLVM. These may make it easier to get LLVM into a distribution. This can be done with the following commands:
make dist # Build the distribution source tarball make dist-check # Check that the source tarball can build itself. cp llvm-M.m.tar.gz /usr/src/redhat/SOURCES # Required by rpmbuild make srpm # for source rpm make rpm # for binary rpm
First, use "make dist" to simply build the distribution. Any failures need to be corrected (on the branch). Once "make dist" can be successful, do "make dist-check". This target will do the same thing as the 'dist' target but also test that distribution to make sure it can build itself and runs "make check" as well. This ensures that needed files are not missing and that the src tarball can be successfully unpacked, built, installed, and cleaned. Once you have a reliable tarball, you need to copy it to the /usr/src/redhat/SOURCES directory which is a requirement of the rpmbuild tool. The last two "make" invocations just run rpmbuild to build either a source (srpm) or binary (rpm) RPM package.
Creating the LLVM GCC binary distribution requires performing the following steps for each supported platform:
Check out the llvm-www module from cvs. Create a new subdirectory X.X in the releases directory. Place the llvm, llvm-test, llvm-gcc source, and llvm-gcc binaries in this new directory. Copy the llvm/docs and LICENSE.txt files into this new directory. Update the releases/download.html file with the new release. Update the releases/index.html with the new release. Finally, update the main page ( index.html and sidebar) to point to the new release and release announcement. Make sure this all gets commited back into cvs.
The first thing you need to understand is that there are multiple make targets to support this feature. Here's an overview, we'll delve into the details later.
Okay, that's the basic functionality. When making a release, we want to ensure that the tree you build the distribution from passes dist-check. Beyond fixing the usual bugs, there is generally one impediment to making the release in this fashion: missing files. The dist-check process guards against that possibility. It will either fail and that failure will indicate what's missing, or it will succeed meaning that it has proved that the tarballs can actually succeed in building LLVM correctly and that it passes make check.
This target builds the distribution directory which is the directory from which the tarballs are generated. The distribution directory has the same name as the release, e.g. LLVM-1.7). This target goes through the following process:
To control the process of making the distribution directory correctly, each Makefile can utilize two features:
You will see various messages if things go wrong:
This target does exactly what distdir target does, but also includes assembling the tarballs. There are actually four related targets here:
This target checks the distribution. The basic idea is that it unpacks the distribution tarball and ensures that it can build. It takes the following actions:
If it can pass all that, the distribution will be deemed distribution worth y and you will see:
===== LLVM-1.7.tar.gz Ready For Distribution =====
This means the tarball should then be tested on other platforms and have the nightly test run against it. If those all pass, THEN it is ready for distribution.
A note about disk space: using dist-check will easily triple the amount of disk space your build tree is using. You might want to check available space before you begin.
In addition to doing a normal clean, this target will clean up the files and directories created by the distribution targets. In particular the distribution directory (LLVM-X.X), check directory (_distcheckdir), and the various tarballs will be removed. You do this after the release has shipped and you no longer need this stuff in your build tree.