Add skeleton chapter on Cygnus
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|The very first (beta) release of GCC (then known as the "GNU C Compiler") was made [http://groups.google.com/groups?selm=523%40ima.UUCP&output=gplain [on 22 March 1987]]:||The very first (beta) release of GCC (then known as the "GNU C Compiler") was made [http://groups.google.com/groups?selm=523%40ima.UUCP&output=gplain on 22 March 1987]:|
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|Since then, there have been several [http://gcc.gnu.org/releases.html [releases]] of GCC. It has grown to support more languages,''many''more architectures and sports many, many more optimisations.||Since then, there have been several [http://gcc.gnu.org/releases.html releases] of GCC. It has grown to support more languages, ''many'' more architectures and sports many, many more optimisations.|
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|To quote from [http://www.gnu.org/gnu/thegnuproject.html [The GNU Project]]:||To quote from [http://www.gnu.org/gnu/thegnuproject.html The GNU Project]:|
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|To quote Michael Tiemann from [http://www.oreilly.com/catalog/opensources/book/tiemans.html [Open Sources]]||To quote Michael Tiemann from [http://www.oreilly.com/catalog/opensources/book/tiemans.html Open Sources]|
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|project. From the [http://gcc.gnu.org/news/announcement.html [original EGCS announcement]]:||project. From the [http://gcc.gnu.org/news/announcement.html original EGCS announcement]:|
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|GCC development these days follows a well-defined [http://gcc.gnu.org/develop.html [development plan]] under the able guidance of the [http://gcc.gnu.org/steering.html [GCC Steering Committee]].||GCC development these days follows a well-defined [http://gcc.gnu.org/develop.html development plan] under the able guidance of the [http://gcc.gnu.org/steering.html GCC Steering Committee].|
A Brief History of GCC
The very first (beta) release of GCC (then known as the "GNU C Compiler") was made [http://groups.google.com/groups?selm=523%40ima.UUCP&output=gplain on 22 March 1987]:
Date: Sun, 22 Mar 87 10:56:56 EST From: rms (Richard M. Stallman) The GNU C compiler is now available for ftp from the file /u2/emacs/gcc.tar on prep.ai.mit.edu. This includes machine descriptions for vax and sun, 60 pages of documentation on writing machine descriptions (internals.texinfo, internals.dvi and Info file internals). This also contains the ANSI standard (Nov 86) C preprocessor and 30 pages of reference manual for it. This compiler compiles itself correctly on the 68020 and did so recently on the vax. It recently compiled Emacs correctly on the 68020, and has also compiled tex-in-C and Kyoto Common Lisp. However, it probably still has numerous bugs that I hope you will find for me. I will be away for a month, so bugs reported now will not be handled until then. If you can't ftp, you can order a compiler beta-test tape from the Free Software Foundation for $150 (plus 5% sales tax in Massachusetts, or plus $15 overseas if you want air mail). Free Software Foundation 1000 Mass Ave Cambridge, MA 02138
Since then, there have been several [http://gcc.gnu.org/releases.html releases] of GCC. It has grown to support more languages, many more architectures and sports many, many more optimisations.
The Early Days
Richard Stallman (a.k.a. RMS) wanted a Free C compiler for the GNU project he had started in 1984.
To quote from [http://www.gnu.org/gnu/thegnuproject.html The GNU Project]:
Shortly before beginning the GNU project, I heard about the Free University Compiler Kit, also known as VUCK. (The Dutch word for "free" is written with a V.) This was a compiler designed to handle multiple languages, including C and Pascal, and to support multiple target machines. I wrote to its author asking if GNU could use it. He responded derisively, stating that the university was free but the compiler was not. I therefore decided that my first program for the GNU project would be a multi-language, multi-platform compiler. Hoping to avoid the need to write the whole compiler myself, I obtained the source code for the Pastel compiler, which was a multi-platform compiler developed at Lawrence Livermore Lab. It supported, and was written in, an extended version of Pascal, designed to be a system-programming language. I added a C front end, and began porting it to the Motorola 68000 computer. But I had to give that up when I discovered that the compiler needed many megabytes of stack space, and the available 68000 Unix system would only allow 64k. I then realized that the Pastel compiler functioned by parsing the entire input file into a syntax tree, converting the whole syntax tree into a chain of "instructions", and then generating the whole output file, without ever freeing any storage. At this point, I concluded I would have to write a new compiler from scratch. That new compiler is now known as GCC; none of the Pastel compiler is used in it, but I managed to adapt and use the C front end that I had written.
The Cygnus Years
To quote Michael Tiemann from [http://www.oreilly.com/catalog/opensources/book/tiemans.html Open Sources]
The GNU compiler already supported dozens of host environments and over a dozen target architectures (I had written six of the ports myself ), making it one of the most widely ported compilers of its time. [...] First, GCC was in the process of transitioning from Version 1.42 to Version 2.0. While GCC Version 1 was good enough to beat most compilers on CISC machines like the m68k and the VAX, lots of new optimizations were needed to make it competitive on RISC platforms. When I did the first GCC port to the SPARC in 1988, GCC was 20% slower than Sun's compiler. I wrote an instruction scheduler in 1989 that narrowed the gap to 10%, and I worked on a branch scheduler that same year that, with the instruction scheduler, got GCC to within 5% of Sun's compiler. With the world transitioning from CISC to RISC, we went from having hands-down the best compiler in almost every regard to a more complex set of tradeoffs the customer would have to evaluate. It was no longer a simple, straightforward sell. Second, GNU C++ was falling behind. I wrote GNU C++ in the fall of 1987, making it the first native-code C++ compiler in the world. C++ was a much more complex language than C, and it was still evolving when we started Cygnus. In 1990, several new, even more complex features became "standard," and with all the distractions of Cygnus, I had no time to keep GNU C++ current.
The Cygnus GNUPro toolkit included GCC support for over 175 host/target combinations by 1999.
GCC development in the early days was a bit too conservative for the tastes of many an eager hacker. Several of the frustrated developers started their own forks of GCC in the hopes of getting their changes much faster to end users. In 1997, several of these hackers got together to create the EGCS project. From the [http://gcc.gnu.org/news/announcement.html original EGCS announcement]:
From: firstname.lastname@example.org (D.V. Henkel-Wallace) Subject: A new project to merge the existing GCC forks Date: Fri, 15 Aug 1997 16:31:29 -0700 To: email@example.com A bunch of us (including Fortran, Linux, Intel and RTEMS hackers) have decided to start a more experimental development project, just like Cygnus and the FSF started the gcc2 project about 6 years ago. Only this time the net community with which we are working is larger! We are calling this project 'egcs' (pronounced 'eggs'). Why are we doing this? It's become increasingly clear in the course of hacking events that the FSF's needs for gcc2 are at odds with the objectives of many in the community who have done lots of hacking and improvement over the years. GCC is part of the FSF's publicity for the GNU project, as well as being the GNU system's compiler, so stability is paramount for them. On the other hand, Cygnus, the Linux folks, the pgcc folks, the Fortran folks and many others have done development work which has not yet gone into the GCC2 tree despite years of efforts to make it possible. This situation has resulted in a lot of strong words on the gcc2 mailing list which really is a shame since at the heart we all want the same thing: the continued success of gcc, the FSF, and Free Software in general. Apart from ill will, this is leading to great divergence which is increasingly making it harder for us all to work together -- It is almost as if we each had a proprietary compiler! Thus we are merging our efforts, building something that won't damage the stability of gcc2, so that we can have the best of both worlds. As you can see from the list below, we represent a diverse collection of streams of GCC development. These forks are painful and waste time; we are bringing our efforts together to simplify the development of new features. We expect that the gcc2 and egcs communities will continue to overlap to a great extent, since they're both working on GCC and both working on Free Software. All code will continue to be assigned to the FSF exactly as before and will be passed on to the gcc2 maintainers for ultimate inclusion into the gcc2 tree. Because the two projects have different objectives, there will be different sets of maintainers. Provisionally we have agreed that Jim Wilson is to act as the egcs maintainer and Jason Merrill as the maintainer of the egcs C++ front end. Craig Burley will continue to maintain the Fortran front end code in both efforts. What new features will be coming up soon? There is such a backlog of tested, un-merged-in features that we have been able to pick a useful initial set: New alias analysis support from John F. Carr. g77 (with some performance patches). A C++ repository for G++. A new instruction scheduler from IBM Haifa. A regmove pass (2-address machine optimizations that in future will help with compilation for the x86 and for now will help with some RISC machines). This will use the development snapshot of 3 August 97 as its base -- in other words we're not starting from the 18 month old gcc-2.7 release, but from a recent development snapshot with all the last 18 months' improvements, including major work on G++. We plan an initial release for the end of August. The second release will include some subset of the following: global cse and partial redundancy elimination. live range splitting. More features of IBM Haifa's instruction scheduling, including software pipelining, and branch scheduling. sibling call opts. various new embedded targets. Further work on regmove. The egcs mailing list at cygnus.com will be used to discuss and prioritize these features. How to join: send mail to firstname.lastname@example.org. That list is under majordomo. We have a web page that describes the various mailing lists and has this information at: http://egcs.cygnus.com. Alternatively, look for these releases as they spread through other projects such as RTEMS, Linux, etc. Come join us! David Henkel-Wallace (for the egcs members, who currently include, among others): Per Bothner Joe Buck Craig Burley John F. Carr Stan Cox David Edelsohn Kaveh R. Ghazi Richard Henderson David Henkel-Wallace Gordon Irlam Jakub Jelinek Kim Knuttila Gavin Koch Jeff Law Marc Lehmann H.J. Lu Jason Merrill Michael Meissner David S. Miller Toon Moene Jason Molenda Andreas Schwab Joel Sherrill Ian Lance Taylor Jim Wilson
In April 1999, after a long period of behind-the-scenes negotiation, EGCS and GCC reunited, and EGCS was accepted as the GNU Project's official GCC. At that time, GCC was renamed from "GNU C Compiler" to "GNU Compiler Collection", which conveniently has the same acronym. The first compiler version released after the reunification was GCC version 2.95.