[swift-dev] updating Clang/LLVM stable branches

[Bob Wilson]

> On Jan 17, 2017, at 1:41 PM, Bob Wilson via swift-dev <swift-dev at swift.org> wrote:
> 
> As I mentioned yesterday, once the last swift-3.1 merge is done, we are planning to update the stable branches for Clang/LLVM to use the new swift-4.0 branches that are aligned with LLVM 4.0. I was expecting we would do that today, but we’re going to wait until tomorrow (Wednesday) morning instead. That will give us time to get all the master-next bots passing and should also be less disruptive than making the switch in the middle of the day.

This is done now. You will need to rebuild Clang and LLVM.

I am also about to push a new swift-4.0-branch in the Swift repo. Please do not make changes there. All development for Swift 4 should continue on the master branch. The point of this new branch is to have a version of Swift that is aligned with Swift 3.1 but builds against the newer version of Clang/LLVM (i.e., the swift-4.0-branch version). As in the past, for the Swift repos we’ll rebranch swift-4.0-branch repeatedly over the course of Swift 4 development, but for the clang, llvm, and compiler-rt repos, we will only be cherry-picking individual commits to swift-4.0-branch.

If you need to make changes to Clang/LLVM for Swift, please make pull requests to get those changes into swift-4.0-branch. If the changes are appropriate for upstream Clang/LLVM, please get the changes there first; otherwise, they should first go to the upstream-with-swift branch on our GitHub repos.