[LLVMdev] Offer of membership to LLVM into the Software Freedom Conservancy, Inc.

[Owen Anderson]

On Sep 19, 2012, at 3:56 PM, dag at cray.com wrote:

> Chris Lattner <clattner at apple.com> writes:
>> We are not interested in copyright enforcement at all.  In personal
>> discussions with Bradley, he mentioned that they may be able to help
>> us move the codebase to the MIT license, which would clarify that
>> issue as well as resolve the current issues around runtime libraries.
> 
> Thanks for clarifying, this is helpful.  What's the motivation for
> moving to the MIT license?  Something more than general familiarity?
> 
> What's the issue with runtime libraries?

I Am Not A Lawyer, etc….

My understanding is that the issue is about the "advertising" clause in the UIUC license, similar to old-style BSD licenses.  It generally isn't much of a problem to reproduce the copyright header in the documentation for a compiler that is based on LLVM.  However, it's not an appropriate clause for a runtime library that will be linked into applications compiled *by* LLVM.  We don't want to force our users to have an LLVM copyright header included with their binaries just because we linked them against compiler-rt.  That is why compiler-rt is dual licensed with the MIT license today.

This, then, creates the issue that we have LLVM sub-projects that do not have the same license as the main project, which in turn means we can't free move code between the various sub-projects and the main project.  I know that the Address Sanitizer guys have had issues with this when developing their runtime library.

--Owen