&gt; gcc&#x27;s project steering is philosophically opposed to allowing non-free (as in GPL) plugins<p>I think that&#x27;s the right philosophy. Why shouldn&#x27;t you be contributing your plugin if you derive value from it, so that other people can derive value from it just as you did with GCC (if you distribute it that is - if you wrote it inhouse for internal use, then it doesn&#x27;t matter at all!).<p>It&#x27;s not like the code generated by GCC is licensed virally.<p>It&#x27;s a shame that GCC&#x27;s code is hard to modify, and difficult to extend. LLVM&#x27;s permissive license means that contributions don&#x27;t flow back unless it&#x27;s favourable to the entity contributing it (such as good PR). I imagine that if somebody&#x2F;some company wrote an excellent, non-obvious, non-trivial toolchain using LLVM, derive profit from it, they will not _want_ to contribute it back.