[flang-dev] Out-of-tree flang builds

Peter Steinfeld via flang-dev flang-dev at lists.llvm.org
Fri Jul 31 11:40:09 PDT 2020

Out-of-tree builds are a way to build only the flang code using a pre-existing full build of llvm.  Out-of-tree flang builds are four times faster than full builds.  Thus, for those of us actively developing code and reviewing other people's changes, out-of-tree builds significantly improve our productivity.

Unfortunately, out-of-tree builds are not currently supported by the llvm buildbots.  Thus, people changing build files must test this feature themselves.  The process of doing an out-of-tree build is described in the flang overview document -- https://github.com/llvm/llvm-project/tree/master/flang.  Alternatively, people changing build files could ask someone familiar with out-of-tree builds to review their changes.

A recent update from David Truby broke out-of-tree builds -- https://reviews.llvm.org/D84022.  In the conversation in the Phabricator review, David states that he understands that "out-of-tree builds are considered a "best effort" feature that isn't guaranteed to work".  But since out-of-tree builds are critical for my development, I don't consider them optional.

I'm writing this note to bring this issue to the broader flang community.  I consider out-of-tree builds to be a critical feature that no change should break.  What do you think?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/flang-dev/attachments/20200731/bcd2a50b/attachment.html>

More information about the flang-dev mailing list