LLVM 2.9 Begins Lining Up For Release

Not only is GCC 4.6 on the way, but the developers at Apple and elsewhere are preparing to release version 2.9 of LLVM, the Low-Level Virtual Machine.

The LLVM 2.9 code-base was now branched from its mainline tree and plans have been drafted for the LLVM 2.9 release.

We're now into phase one of testing for LLVM, which will last until the 14th of this month and only patches for regressions from LLVM 2.8 will be accepted along with clean-up with for existing features.

Phase 2 begins later in the month and only patches for critical bugs will make it into the LLVM 2.9 branch. That's it, unless there are critical bugs or regressions found late in phase 2, in which case a third phase will be carried out. The final release of LLVM 2.9 is scheduled for the 3rd of April.

Worth noting is that LLVM 2.9 is the last release to support LLVM-GCC. The LLVM-GCC front-end is being discontinued in favor of using DragonEgg. DragonEgg is the GCC plug-in for GCC 4.5+ that makes it quite easier to deploy LLVM's optimization abilities within the GNU Compiler Collection in a much easier and cleaner fashion.

Greater attention will also turn to just using Clang, the LLVM C/C++ front-end compiler, now that it's becoming quite mature so there is less dependence upon GCC. "Starting with the 3.0 release, Clang will be the main compiler for most people. For those who wish to use a GCC-compatible front-end or who use non-C languages, there is Duncan's DragonEgg project."

So it sounds like LLVM 3.0 will be the next release too. Read more in the LLVM 2.9 testing announcement.

See my benchmarks of LLVM 2.9 on Intel Sandy Bridge, GCC and Clang on the Intel Atom, and benchmarks of GCC / LLVM-GCC / Clang / DragonEgg.

The timing of this release is also quite ideal as automated LLVM testing will be starting up in the coming days on the Phoronix Test Farm using Phoromatic and OpenBenchmarking.org. Other Low-Level Virtual Machine benchmarks are also coming. Matthew Tippett and I will be speaking at the Linux Foundation Summit next month during the LLVM track about LLVM testing.