Re: Ada on Apple's new procesors

[Simon Wright <simon@pushface.org>]

Optikos <ZUERCHER_Andreas@outlook.com> writes:

> Without paying a hefty proprietary-licensing fee to AdaCore, isn't
> GNAT-LLVM distributed only under pure GPLv3 without the Runtime
> Library Exception (RLE)?  Wouldn't that mean that GNAT-LLVM on MacOS
> (and iOS) can be utilized by software distributed under GPL-compatible
> licenses, lest that software violate terms of GPLv3?

GCC itself is distributed under pure GPLv3, and the RLE[1] is irrelevant
to that distribution.

The gnat you are straining at is whether a compiler formed by merging
GNAT-LLVM with GCC can be used in an "eligible compilation process". If
so, the RLE will apply:

   "You have permission to propagate a work of Target Code formed by
   combining the Runtime Library with Independent Modules, even if such
   propagation would otherwise violate the terms of GPLv3, provided that
   all Target Code was generated by Eligible Compilation Processes. You
   may then convey such a combination under terms of your choice,
   consistent with the licensing of the Independent Modules."

A "compilation process"

   "transforms code entirely represented in non-intermediate languages
   designed for human-written code, and/or in Java Virtual Machine byte
   code, into Target Code."

A compilation process is "eligible"

   "if it is done using GCC, alone or with other GPL-compatible
   software, or if it is done without using any work based on GCC. For
   example, using non-GPL-compatible Software to optimize any GCC
   intermediate representations would not qualify as an Eligible
   Compilation Process."

But!

(a) if you look at the LLVM license[2], you will see at the top that
it's the Apache License v2.0 (with some irrelevant extensions);

(b) in [3] & [4], the Apache License v2.0 is listed as GPLv3-compatible.

So! what's the problem? GNAT-LLVM clearly provides an eligible
compilation process.

[1] https://www.gnu.org/licenses/gcc-exception-3.1.en.html
[2] https://releases.llvm.org/10.0.0/LICENSE.TXT
[3]
http://gplv3.fsf.org/wiki/index.php/Compatible_licenses#GPLv3-compatible_licenses
[4] https://www.gnu.org/licenses/license-list.en.html#GPLCompatibleLicenses