You may find this link helpful for both the <i>why</i> and <i>how</i>: <a href="http:&#x2F;&#x2F;adriansampson.net&#x2F;blog&#x2F;llvm.html" rel="nofollow">http:&#x2F;&#x2F;adriansampson.net&#x2F;blog&#x2F;llvm.html</a><p>( HN discussion: <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=9998140" rel="nofollow">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=9998140</a> )