Multithreading tests and diagnostics

[sjavora]

Addresses this FIXME. Also adds tests for the // Multithreading extension.

[DougGregor]

@swift-ci please test

[sjavora]

/home/buildnode/jenkins/workspace/pr-swift-driver-linux/branch-master/swift-driver/Tests/SwiftDriverTests/SwiftDriverTests.swift:169: error: SwiftDriverTests.testMultithreading : XCTAssertEqual threw error "unableToFind(tool: "clang")" -

Not sure what's going on here - the tests don't do anything special 🤔

[DougGregor]

Hmm. Perhaps you need to add an explicit -target to your Driver invocations, e.g., as in nhttps://github.com/apple/swift-driver/blob/master/Tests/SwiftDriverTests/SwiftDriverTests.swift#L232

[DougGregor]

We might have some configuration issues with finding clang on Linux consistently. @harlanhaskins do you know of any problems here?

[harlanhaskins]

Every time I've run it on Linux, clang has been in my PATH. Is it not in the PATH on the bots?

Also, we really need to figure out toolchain-relative lookups 😕

[DougGregor]

Every time I've run it on Linux, clang has been in my PATH. Is it not in the PATH on the bots?

Also, we really need to figure out toolchain-relative lookups :/

Yes, definitely.

[sjavora]

https://github.com/apple/swift-driver/blob/master/Tests/SwiftDriverTests/SwiftDriverTests.swift#L232

@DougGregor so this should work? I only have access to a Mac at the moment so I can't really test this. Also, the test failed only on the last assert - should I add the target only there or to all the invocations?

[sjavora]

Added the target argument to the one failing assert for now.

[DougGregor]

@swift-ci please test

[DougGregor]

@swift-ci test

[sjavora]

@DougGregor now it failed on the other test - added target there as well, hopefully this will finally pass. I'm sorry about all the hassle for such small changes 😞

[DougGregor]

@swift-ci please test

[DougGregor]

@swift-ci please test

[DougGregor]

No worries; we need to figure out how best to find tools within our toolchain so these tests will become target-agnostic, but that's a separate issue.

[sjavora]

@DougGregor thanks! Should I open a PR to make some other diagnostics internal? If so, which ones?

Better yet, is there a place to discuss this project on the Swift forums? https://forums.swift.org/c/development/tooling?

[DougGregor]

Yes, I think I'd like to make all of the diagnostics internal. For discussions, I recommend https://forums.swift.org/c/development/compiler