Continuity problems

Posted Mar 22, 2012 18:51 UTC (Thu) by Lionel_Debroux (subscriber, #30014)
In reply to: Continuity problems by josh
Parent article: GCC celebrates 25 years with the 4.7.0 release

Another thing that would reduce the pain to contribute to GCC is a code base with a lower entry barrier. Despite the introduction of the plugin architecture in GCC, which already lowered it quite a bit, the GCC code base remains held as harder to hack on, less modular, less versatile than the LLVM/Clang code base.

The rate of progress on Clang has been impressive: self-hosting occurred only two years ago, followed three months later by building Boost without defect macros, and six months later by building Qt. On the day g++ 4.7 is released, clang++ is the only compiler whose C++11 support can be said to rival that of g++ (clang++ doesn't support atomics and forward declarations for enums, but fully supports alignment).

GCC isn't alone in not having switched to DVCS yet: LLVM, and its sub-projects, haven't either... However, getting commit access there is quite easy, and no copyright assignment paperwork is required.

Continuity problems

Posted Mar 23, 2012 3:20 UTC (Fri) by wahern (subscriber, #37304) [Link] (1 responses)

I've delved into both GCC and clang to write patches, albeit simple ones. GCC is definitely arcane, but both are pretty impenetrable initially. You can glance at the clang source code and fool yourself into thinking it's easy to hack, but there's no shortage of things to complain about.

Compiler writing is extremely well trodden ground. It shouldn't be surprising that it's fairly easy to go from 0-60 quickly. But it's a marathon, not a sprint. The true test of clang/LLVM is whether it can weather having successive generations of developers hack on it without turning into something that's impossible to work with. GCC has clearly managed this, despite all the moaning, and despite not being sprinkled with magic C++/OOP fairy dust. The past few years have seen tremendously complex features added, and clang/LLVM isn't keeping apace.

And as far as C++11 support, they look neck-and-neck to me:

http://clang.llvm.org/cxx_status.html
http://gcc.gnu.org/projects/cxx0x.html

Continuity problems

Posted Mar 25, 2012 0:49 UTC (Sun) by nix (subscriber, #2304) [Link]

I'd say that by about the time of the egcs fork GCC was close to impossible to hack on. Cruft piled on cruft. However, starting in the 3.x eras a determined effort was made to fix this (still underway: tree-ssa was a massive improvement, but it couldn't have been done without other cleanups), and it is now very much nicer.