Raise min LLVM version to 3.9

[kinke]

No description provided.

[JohanEngelen]

Certainly in favor of this.

To prevent complaints later: https://forum.dlang.org/post/bmsdqayozfuxvbuwklbu@forum.dlang.org

[dnadlinger]

+1, unless the forum thread brings up anything.

[kinke]

[I forgot to remove the FileCheck and llvm-profdata .cpp files, amended now.]

[joakim-noah]

Heh, I didn't know how much work had gone into supporting these old LLVM versions.

[dnadlinger]

Yep, the diff is nice – it's mostly leaving old code behind for a while though after tracking API changes, so not that bad.

[kinke]

It cost me time to find a workaround in #2870, and more importantly, is a PITA for the debuginfo API changes taking place between 3.7 and 3.9, which required poor Syniurge to figure out the necessary adaptations in #2826.

[kinke]

So the plan is to merge this tomorrow (giving people one week to respond to the forum thread), then adapt & merge #2870 and #2826.

[dnadlinger]

(Oh yes, that's definitely a good idea. I was responding only to Joakim's comment about the amount of effort to support old versions, where in actuality, the effort is mostly spent on new versions.)

[Geod24]

DMD's BuildKite is broken and the logs seem to point to this PR.
Failing build: https://buildkite.com/dlang/dmd/builds/1916#7d52edc4-50c7-49ef-9daa-50d456217d55

Logs:

-- Looking for unistd.h - found
--
  | -- GDB 7.11.1 detected
  | CMake Error at tests/CMakeLists.txt:22 (include):
  | include could not find load file:
  |  
  | /usr/lib/llvm-3.8/lib/cmake/llvm/LLVMConfig.cmake
  | Call Stack (most recent call first):
  | tests/CMakeLists.txt:27 (get_host_arch)
  |  
  |  
  | -- LDC_HOST_ARCH:
  | -- Configuring incomplete, errors occurred!
  | See also "/var/lib/buildkite-agent/builds/buildkite-agent-03-1/dlang/dmd/build/ldc-developers-ldc/bootstrap/CMakeFiles/CMakeOutput.log".
  | See also "/var/lib/buildkite-agent/builds/buildkite-agent-03-1/dlang/dmd/build/ldc-developers-ldc/bootstrap/CMakeFiles/CMakeError.log".
  | 🚨 Error: The command exited with status 1

Looks like we're trying to use 3.8. See this issue to continue the discussion.

[joakim-noah]

Looks like the CMake config still allows 3.7/8, needs to be updated.

[kinke]

Yeah, I grepped for 30{7,8,9}, missing 3.7 here.
BuildKite still not allowing public logs access is a PITA, I don't have the credentials at hand here at work. I guess the build image is based on Ubuntu 16.04 with its LLVM 3.8.

Edit: Ah, already fixed (the DMD problem), thx Joakim.

[wilzbach]

BuildKite still not allowing public logs access is a PITA

Yeah, but you can use:

User: dummy@dlang.io
Pw: dlangrocks

until they finally fix that.