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digitalmars.D.ldc - Licensing of PGO instrumented code.

reply Johan Engelen <j j.nl> writes:
Hi all,
   I just discovered an important licensing issue with the use of 
LLVM compiler-rt's code for _instrumenting_ code for PGO. The 
problem is that with -fprofile-instr-generate, we link with a 
piece of LLVM's compiler-rt code. The compiler-rt license reads:
"Redistributions in binary form must reproduce the above 
copyright notice, this list of conditions and the following 
disclaimer in the documentation and/or other materials provided 
with the distribution."

Basically, a program compiled with `-fprofile-instr-generate` 
will have a piece of compiler-rt inside of it, and redistributing 
that file will need to be accompanied with the compiler-rt 
license and the other requirements.

Important note: this does not concern programs compiled with 
`-fprofile-instr-use`. So only PGO instrumented binaries need the 
compiler-rt license when distributed, not PGO optimized binaries. 
In practice, I think it is rare to distribute instrumented 
binaries, but not unthinkable.

There is currently an LLVM discussion about relicensing 
compiler-rt to allow unattributed binary form distribution, to 
solve this problem as far as I understand.
http://lists.llvm.org/pipermail/llvm-dev/2016-September/104778.html

How do we address this issue?

(I think we need to have information on this ASAP in our LICENSE 
file. Tomorrow, I will work on it.)

-Johan
Sep 15 2016
parent reply David Nadlinger via digitalmars-d-ldc <digitalmars-d-ldc puremagic.com> writes:
On 15 Sep 2016, at 23:23, Johan Engelen via digitalmars-d-ldc wrote:

 There is currently an LLVM discussion about relicensing compiler-rt to 
 allow unattributed binary form distribution, to solve this problem as 
 far as I understand.
 http://lists.llvm.org/pipermail/llvm-dev/2016-September/104778.html

 How do we address this issue?


What are the Rust people doing? (IIRC they depend on compiler-rt by 
default, right?)

  — David
Sep 15 2016
parent reply Johan Engelen <j j.nl> writes:
On Thursday, 15 September 2016 at 22:37:55 UTC, David Nadlinger 
wrote:

 On 15 Sep 2016, at 23:23, Johan Engelen via digitalmars-d-ldc 
 wrote:

 There is currently an LLVM discussion about relicensing 
 compiler-rt to allow unattributed binary form distribution, to 
 solve this problem as far as I understand.
 http://lists.llvm.org/pipermail/llvm-dev/2016-September/104778.html

 How do we address this issue?


 What are the Rust people doing? (IIRC they depend on 
 compiler-rt by default, right?)


Thanks for that pointer.
It lead me to this:
https://www.reddit.com/r/rust/comments/2db531/how_to_display_the_rust_copyright_notice_in/

Which lead me to this:
http://llvm.org/docs/DeveloperPolicy.html#license
"In addition to the UIUC license, the runtime library components 
of LLVM (compiler_rt, libc++, and libclc) are also licensed under 
the MIT License, which does not contain the binary redistribution 
clause. As a user of these runtime libraries, it means that you 
can choose to use the code under either license (and thus don’t 
need the binary redistribution clause), and as a contributor to 
the code that you agree that any contributions to these libraries 
be licensed under both licenses. We feel that this is important 
for runtime libraries, because they are implicitly linked into 
applications and therefore should not subject those applications 
to the binary redistribution clause."

Thus, I think we should copy the text above into our LICENSE 
file, specifying it for profile-rt (our copy of compiler-rt's 
lib/profile) and include the MIT License. And then we are good to 
go.
Also see Rust's license file: 
https://github.com/rust-lang/rust/blob/master/COPYRIGHT

(Upon further thought I think the relicensing effort in LLVM is 
about being able to move code from LLVM to compiler-rt. The issue 
I am discussing here is actually already solved the dual license.)

-Johan
Sep 16 2016
parent reply Johan Engelen <j j.nl> writes:
On Friday, 16 September 2016 at 09:22:54 UTC, Johan Engelen wrote:

 
 Thus, I think we should copy the text above into our LICENSE 
 file, specifying it for profile-rt (our copy of compiler-rt's 
 lib/profile) and include the MIT License.


To simplify matters, I could relicense my own D code 
(/profile-rt/d/ldc/*) under the same license as compiler-rt.
Is that OK?
Sep 16 2016
parent reply Johan Engelen <j j.nl> writes:
On Friday, 16 September 2016 at 09:46:12 UTC, Johan Engelen wrote:

 
 Is that OK?


I'm the sole author :-)


PR here: https://github.com/ldc-developers/ldc/pull/1765
Sep 16 2016
next sibling parent Intersteller <Galatic.Bacon Outerspace.com> writes:
On Friday, 16 September 2016 at 10:15:04 UTC, Johan Engelen wrote:

 On Friday, 16 September 2016 at 09:46:12 UTC, Johan Engelen 
 wrote:

 
 Is that OK?


 I'm the sole author :-)


 PR here: https://github.com/ldc-developers/ldc/pull/1765


The solution to all this BS is for everyone to simply stop 
believing in the copyright myth!  No one owns anything... God 
owns it all.
Sep 16 2016
prev sibling parent reply Kagamin <spam here.lot> writes:
On Friday, 16 September 2016 at 10:15:04 UTC, Johan Engelen wrote:

 PR here: https://github.com/ldc-developers/ldc/pull/1765


You could keep it as boost, it can be sublicensed as MIT at will. 
AFAIK, boost is a nobrainer license, it's compatible with 
anything. Unless you prefer a stricter one, that is :)
Sep 19 2016
parent Johan Engelen <j j.nl> writes:
On Monday, 19 September 2016 at 18:42:21 UTC, Kagamin wrote:

 On Friday, 16 September 2016 at 10:15:04 UTC, Johan Engelen 
 wrote:

 PR here: https://github.com/ldc-developers/ldc/pull/1765


 You could keep it as boost, it can be sublicensed as MIT at 
 will. AFAIK, boost is a nobrainer license, it's compatible with 
 anything. Unless you prefer a stricter one, that is :)


I prefer it to be the same as the rest of profile-rt. For less 
confusion.
Sep 19 2016