[llvm-dev] RFC: Improving license & patent issues in the LLVM community

Jonas Maebe via llvm-dev llvm-dev at lists.llvm.org
Thu Oct 29 03:25:33 PDT 2015


Regarding the previously voiced concerns of incompatibilities between  
the Apache and GPLv2 license, I'd like to add one more thing.

I work on a, at this time mostly LLVM-unrelated [1], "GPLv2 or later"  
licensed compiler: the Free Pascal Compiler. Some people in the  
project are vehemently opposed to the GPLv3, so a move of our project  
to that license would not be easy (even if legally perfectly possible).

The reason I care about the LLVM license is that I regularly consult  
the Clang source code to find out things that are not documented  
anywhere else. In particular:
a) layout details of Objective-C class/category/interface metadata
b) OS X compilation details, e.g. for which versions of (Mac) OS X and  
iOS do you have to link in which, if any, crt*.o file

Not being able to use the Clang source code anymore as a reference  
point for this kind of information would be a big loss to me. Apple  
just documenting all of this would be equally fine by me, of course,  
but I don't see that happening.


[1] I'm working on an LLVM IR code generator to co-exist with our  
other code generators, but we'll likely never link to LLVM itself to  
ease deployment (different versions of LLVM will be handled in the  
compiler like different architecture versions of actual CPUs).

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