[LLVMdev] Licensing requirements

[Joerg Sonnenberger]

On Tue, Jul 05, 2011 at 04:37:14PM +0200, Tor Gunnar Houeland wrote:
> I'm assuming no portion of LLVM is included in the compiled binaries, 
> only the runtime library components, so that the compiled binaries are 
> not derived from LLVM. Is that true?

Yes. Code compiled with LLVM is not a derived work of LLVM and as such
not subject to the LLVM license.

> The runtime library components state that they are licensed under 
> http://www.opensource.org/licenses/mit-license.php which does not 
> contain a specific clause regarding binary redistribution. This seems to 
> have been interpreted as not placing any restrictions on binary 
> redistribution, i.e. that "all copies" has somehow been interpreted as 
> "copies in source code form". (Different licenses such as Boost, zlib, 
> and bzip2 etc. do not require copyright notices for binary redistributions.)

If you want a hard answer, you have to ask a copyright lawyer. The
normal interpreation is that all copies include binary versions and if
you ship compiled code (e.g. compiler_rt), you have to include a copy of
the license file or the copyright note in your distribution. The MIT
license is generally considered equivalent to the 2-clause BSD license
in this regard.

Note that the GCC runtime doesn't differ in this regard, even with the
exception clause.

> Is it sufficient to include the MIT copyright notices from 
> http://llvm.org/svn/llvm-project/compiler-rt/trunk/LICENSE.TXT / 
> http://llvm.org/svn/llvm-project/libcxx/trunk/LICENSE.TXT for programs 
> compiled with LLVM? (Probably including the respective CREDITS.TXT files 
> as a courtesy, although there doesn't seem to be any actual requirements 
> to indicate that it's for Compiler-RT/libc++)

Yes, if you distribute them with (or in the case of static linkage, as
part of) your program.

> And finally, could it be possible to change the licensing (again) so 
> that no notices would be required?

I don't think that's likely to happen.

Joerg