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Subject: Re: [boost] LLVM license compatibility with BSL
From: Bryce Lelbach (admin_at_[hidden])
Date: 2010-11-17 08:25:11

Hash: SHA1

Um. No, this is inaccurate. libc++ and compiler_rt are dual licensed. That's
all. -ONLY- libc++ and compiler_rt can be used in Boost.

Original announcement from the LLVM list:

Hi All,

I just wanted to let you know that libc++ and compiler_rt and now dual licensed under *both* the UIUC and MIT license. The reason for this is that the UIUC license (like many BSD licenses) requires that binaries that link LLVM code contain a notice that they are derived from LLVM.

This clause doesn't make sense for libraries like libc++ and compiler_rt: these get implicitly added to the link line by the clang driver, so users of the clang compiler don't know that they're linking in pieces of LLVM. For example, if Mozilla was every shipped built with Clang, it should not have to have a notice saying that it has code derived from LLVM (unless they were using the JIT or something other LLVM component).

Since copyright is distributed among all the contributors, we got approval from everyone who has contributed to these two projects, and had to revert one libc++ patch (whose author did not respond to numerous requests). Going forward, contributions to these two projects will require that you allow your code to be used under either license. One bad thing about this change is that it is no longer valid to move code from a "just UIUC licensed" codebase to libc++ or compiler_rt unless the copyright owner approves, but I don't expect this to be a significant issue in practice.

I added a paragraph here to explain this, please let me know if the wording doesn't make sense:

- -Chris

On Tue, 16 Nov 2010 17:21:19 -0500
Howard Hinnant <howard.hinnant_at_[hidden]> wrote:

> On Sep 27, 2010, at 3:17 PM, vicente.botet wrote:
> > Hi,
> >
> > I have found quite useful to adapt the test for llvm/libc++ ratio/chrono to
> > test Boost.Ratio and Boost.Chrono. But Anthony has signaled me that maybe
> > there is a compatibility problem with the license included in these files.
> >
> > //===----------------------------------------------------------------------===//
> > //
> > // The LLVM Compiler Infrastructure
> > //
> > // This file is distributed under the University of Illinois Open Source
> > // License. See LICENSE.TXT for details.
> > //
> > //===----------------------------------------------------------------------===//
> >
> > Is the LLVM License (
> > compatible with the Boost Software License?
> >
> > Can we include files with this comment on a Boost library?
> >
> > Best,
> > _____________________
> > Vicente Juan Botet Escribá
> >
> > _______________________________________________
> > Unsubscribe & other changes:
> >
> We have just managed to change the license under which llvm/libc++ is
> released. It is now dual licensed under *both* the UIUC and MIT license. The
> code can be used under either license (see the top of the file), LICENSE.txt
> contains the full wording of both licenses. The MIT license does not contain
> the binary redistribution clause.
> More details here:
> It is our hope that this will ease the concerns expressed here regarding
> compatibility with the boost license.
> -Howard
> _______________________________________________
> Unsubscribe & other changes:

- --
Bryce Lelbach aka wash
Version: GnuPG v1.4.9 (GNU/Linux)


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