[llvm-dev] Clang-12 fails build on MacOS

[Steven Wu via llvm-dev]

Darwin build is a bit different from other build. I would look for a fix that avoid that race conditions rather than hard code targets.

Also I don’t know what you mean by giving the workaround a try. The initial workaround I provide is about altering build configuration which is mostly on the user unless you are using the cmake cache in the repo. We also never hit that problem on our side since we always build with ninja and it appears ninja doesn’t schedule the copy close to each other.

Steven 

> On Jul 18, 2021, at 11:32 AM, Blumenthal, Uri - 0553 - MITLL <uri at ll.mit.edu> wrote:
> 
> It appears that the proposed workaround had been tested and proven to work. 
> 
> Which is why I'm asking to give it a try. 
> 
> Perhaps doing that would help understanding the root cause too.
> 
> Regards,
> Uri
> 
>> On Jul 18, 2021, at 14:27, Raul Tambre <raul at tambre.ee> wrote:
>> 
>> Thanks for the info, however I don't think we still understand the root cause. Why do we end up with two instances trying to create the symlink to the same location?
>> 
>> Per my thinking different targets end up with separate build directories thus this shouldn't happen. And since the different runtime builds are sub-builds your proposed dependency tracking solution wouldn't work.