GNU Tools Cauldron 2013

Recently Google hosted just over 100 GCC (GNU Compiler Collection) developers at our Mountain View, CA headquarters for the 3rd annual GNU Tools Cauldron. The purpose of this 2+ day workshop was to gather GNU tools developers together to coordinate work, exchange reports on ongoing efforts, and discuss development plans for the next 12 months.

For me, the most interesting result was the final realization that GCC is once again in need of a major code base reorganization.  For several quarters we have been working on modernizing the codebase. We switched it to C++, we started converting core data structures and are beating the refactoring drum. All those efforts were not wasted and there are two major efforts in progress now that will fundamentally alter the structure of the compiler.

The one I'm most hopeful about is Red Hat's proposal to extend the modularization effort we had started last year. This will see the compiler split into hermetic modules that will only be able to communicate via well-defined interfaces (if you've ever hacked on GCC, you'll know how much this simplifies life).

The other, related, effort is the removal of all global state from the compiler.  The final goal is to allow the compiler to be turned into a shared library and used for JIT purposes.

Among my favorites of the videos of the presentations from the Cauldron are those dealing with this overhaul of the GCC codebase.  This is going to fundamentally transform GCC internals over the next couple of years. GCC 5.0 will be unrecognizable. Watch the videos on the removal of global state and GCC re-architecture.  Exciting stuff!

Another especially interesting moment at the Cauldron was when Dehao Chen presented his work on AutoFDO.  This work will significantly simplify the usability of FDO technologies.  I can't wait to see this submitted to trunk.

We also had the usual collection of presentations about optimizations, runtime BOFs, new features and “lively discussion” over meals.  Good, geeky times were had by all.

By Diego Novillo, Compiler team

Geek Time with Peter Brown

When the Free Software Foundation’s executive director, Peter Brown, visited the Google offices last week, he graciously offered his time for an interview with Samba co-founder and Open Source Programs Office team member Jeremy Allison. Peter and Jeremy spoke for quite a while about several of the hot topics facing free software today. Some highlights of their conversation include:

• A brief history of the free software movement (0:14)
• The difference between open source and free software (4:12),
• The importance of specifying “GNU/Linux” when referring to the first fully free operating system (7:42),
• Linux Libre, a fully free kernel distribution, including the drivers (12:29)
• The Free Software Foundation’s hardware endorsement program, Respects Your Freedom (13:54)
• Unexpected places that free software is appearing around the world (18:42)
• Peter’s career with the Free Software Foundation (20:50).
• Ways that non-programmers can get involved and support the free software movement (26:23)

Throughout the conversation, both Jeremy and Peter provide fascinating anecdotes about ways that free software is shaping society. The video is an effective introduction to software freedom for those who have just discovered the concept, but it's also a great way for everyone to learn more about free software.

UPDATE: The video is now also available in the open video format WebM.

By Ellen Ko, Open Source Team

gold: Google Releases New and Improved GCC Linker

By Ian Lance Taylor, Systems Software Team


I submitted my first patch to the GNU linker in 1992. In 1993 I knew enough about its shortcomings, and started to argue that we should rewrite it from scratch. In 2006, just 13 years later, and now working at Google, I finally got a chance to do it.

That work came to fruition last month, with the release
of gold to the open source community. gold is a new linker, written from scratch. It really only has one new feature compared to the current GNU linker: it's much faster. I've measured it as five times faster linking large C++ applications. Since for most programmers the linker is nothing more than a roadblock between writing code and running the program, I figure that speed and correctness are the only really important features of any linker.

We've been using gold widely within Google as a beta test, and will soon be deploying it as the default linker internally. Now that it is part of the GNU binutils, my hope is that it will eventually become the default linker for all the free operating systems.

Getting gold to this point was the work of a small team at Google. It's a reasonably sized program — some 50,000 lines of commented C++ code. We're contributing it back to the open source community not because we have to, or because we expect some benefit, but simply because we can. Google gets a lot from the open source community, and we try to give a lot back.

Updates from the Free Software Foundation

By Chris DiBona, Open Source Team

Google's Open Source Team is a proud supporter of many Free and Open Source technical and advocacy organizations. From time to time, we ask that these colleagues give an update to the community about their latest and greatest achievements. Peter Brown, Executive Director of the Free Software Foundation, was kind enough to write in to us:

The Free Software Foundation (FSF) recently held its annual members meeting at MIT in Cambridge, Massachusetts, U.S.A. The meeting is a chance to reflect upon the achievements of the year past and plan for the year ahead. Google has supported our work in the past through our corporate patron program, and this year they have just confirmed that they are renewing their support once again. This seems like a good occasion then to brief Google followers on what work we have been doing and what you can expect from the FSF in the year ahead.

The FSF launched the GNU GPLv3 on June 29, 2007. This was the culmination of an 18-month period to redraft the world's most popular free software license. I am pleased to report that not only have we published a license that protects free software from the latest attempts to make it proprietary, but we have also seen widespread adoption, including developer and corporate support. We have also updated and launched the GNU LGPLv3 and created a new license: the GNU Affero GPLv3. You may have also heard that the FSF, Wikimedia and Creative Commons are cooperating over the new GNU GFDL — the license currently used for all articles on Wikipedia. You can find out more about FSF copyleft licensing at the FSF Licensing and Compliance Lab.

With the release of the GNU AGPLv3, we have also started to make progress on how to tackle the issue of computer user freedom and web services. To that end, we recently hosted a summit, "Freedom for Web Services," as a launching point for a year-long community discussion on this topic. Reports from that summit will be published soon.

The Free Software Foundation sponsors the ongoing development of the GNU project — and many new GNU projects are added every year. GNU now stretches far beyond the core system components found in the typical GNU/Linux distribution. Apart from our own projects we also work to highlight those projects that have a strategic importance to free software. The FSF high priority projects list is currently under review following a recent rash of success, and we hope to relaunch in April with a new set of targets for software development.

In 2008, the FSF will be marking the 25th anniversary of the launch of the GNU project — the starting point for the free operating system GNU/Linux, and the free software movement. We are planning to mark the anniversary with a public awareness campaign. Expect to see lots of people talking about free software during the year ahead. In preparation for that campaign we have updated our website, www.fsf.org, with a new friendly look as we welcome a new audience of users to free software.

Speaking of celebrations, Happy Document Freedom Day! Our campaign for Open Document has been underway since October 2005, and we are helping spread awareness of the need for our public institutions to hold records in formats that we can all utilize. You can join us in this process by sending an email or letter to your national or local government officials or government agencies and politicians. Getting your voice heard on this issue will go a long way in preparing the political ground for the acceptance of free and open formats. There are many other ways you can get involved beyond our Open Document efforts. Head over to our campaign center now or look through our volunteer section to find something that you can get active with.

Part of our public awareness campaign is a major free software event to be held in Massachusetts in the summer of 2009. We are working in collaboration with local educational institutions and other stakeholders to develop an event that will bring developers and users together in a fun and interesting way. We also aim to use the event to highlight the need to draw more young women into computer science. Google's own Leslie Hawthorn has generously joined our planning committee, and you will probably hear updates from her later this year.

Google's support is great to have, but we receive the bulk of our funding from individual contributors and much of the work is done by volunteers. You can join the Free Software Foundation as an Associate Member — it's a great way to get involved and stay connected with our work.

Many thanks to Peter for this report.