[swift] validation-test fail

Hi there, I have been trying to build swift 5.0 from source on linux. The build is fine, however i have experienced clang related error when running the validation test:

/root/swift5/llvm/tools/clang/include/clang/Basic/Diagnostic.h:489: error: undefined reference to 'clang::DiagnosticsEngine::DiagStateMap::dump(clang::SourceManager&, llvm::StringRef) const'
/root/swift5/llvm/tools/clang/include/clang/Basic/Diagnostic.h:491: error: undefined reference to 'clang::DiagnosticsEngine::DiagStateMap::dump(clang::SourceManager&, llvm::StringRef) const'
clang: error: linker command failed with exit code 1 (use -v to see invocation)
[4/43] Building CXX object unittests/IDE/CMakeFiles/SwiftIDETests.dir/Placeholders.cpp.o
ninja: build stopped: subcommand failed.
./utils/build-script: fatal error: command terminated with a non-zero exit status 1, aborting

Any ideas? This is Unbuntu 18.04 with clang 6.0.0.

That sounds like your Swift repo is out of sync with your Clang repo. You can use swift/utils/update-checkout --scheme swift-5.0-branch to make sure they're all consistent.

Thanks for the reply. I did use that command and they are all the same swift-5.0-branch.

Hmm. The bots are definitely blue, https://ci.swift.org/view/swift-5.0-branch/job/oss-swift-5.0-incremental-RA-linux-ubuntu-18_04/. @blangmuir, have you seen this before?

Nope, never seen that. But I don't know if I've ever tried to build swift-5.0-branch on Linux either. @akyrtzi?

I haven't tried either.

What clang version am i suppose to use? This error was seen with clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)