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Comment by hywel | Hacker News Reader

> Already my own experiments suggest that LLVM is a superior compiler, by every metric I know of

Except that it isn't copyleft, which is one of the most important metrics to Stallman, FSF et al, and is why they're unlikely to stop defending it.

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I think the real point is there's defending GCC and there's "defending" GCC. Actually defending GCC means making it as useful and usable you can in the context of a robust, interoperable GNU ecosystem. "Defending" GCC includes creating pointless interoperability barriers and weakening other GNU tools in the guide of "protecting" copylefted crown jewels that no one wants to steal any more (those people have long since moved on to clang).

This suggests that the FSF should create a GPL-licensed fork a Clang/LLVM. Such a fork could continue to receive all upstream improvements (since they're under a more liberal license), but not the other way around - the upstream project would not be able to use patches licensed under the GPL. Thus (in theory) it could end up being strictly superior to the original.

Didn't we go all over this when a hostile GPL re-licensing of a (painfully) reverse engineered OpenBSD driver was attempted?

I'm not sure what you could do, that would also be attractive for people to use and contribute to, that would add enough GPL content to make such a thing fly even in theory.

Maybe add a bunch of the GCC backends to LLVM? That's where it's most conspicuously behind GCC. There's also the precedent of GCC derived pre-Clang front ends, although I don't know how many of the non-C and C++ GCC front ends are seriously important (there's Ada, but that's got its own complexities).

>> This suggests that the FSF should create a GPL-licensed fork a Clang/LLVM.

To do that you need developer support for the fork, so it won't happen now. It won't happen until enough people are sufficiently upset with the current development path, and if/when that happens it will probably not be due to the license.

This is a common FSF tactic. It doesn't always end well (both GNU TLS, and GNU Mach come to mind). Not necessarily because they do bad things, but because they aren't able to get enough people using the software to make a significant improvement.

If clang/LLVM caught up in generated code performance to GCC then I must admit that is news to me.

Since clang 3.5 (or possibly even earlier), clang has basically been neck-in-neck with GCC. Most benchmarks seem to show the two basically equal to each other, and then there's a handful where clang wins outright and a handful where GCC wins outright. [1]

For my own use-case (a high-performance photorealistic renderer threaded using TBB), my clang builds outperform my gcc builds, but of course that's completely anecdotal and based on just my own use-case.

[1] http://www.phoronix.com/scan.php?page=article&item=gcc49_com...

It is copyleft. In fact they leave you more rights to copy the source than GPL.

http://www.gnu.org/copyleft/

From http://llvm.org/docs/DeveloperPolicy.html#license:

"LLVM’s license is not a “copyleft” license like the GPL."

Rights to copy the source is not what copyleft means.

No it isn't copyleft, I'm not sure you know what "copyleft" means.

The word "copyleft" has a meaning. Please, don't polute the discussion with missleading political speech trying to change its meaning.

Open source: yes

Free/Libre software: yes (https://www.gnu.org/philosophy/license-list.html#GPLCompatib...)

Copyleft: no

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