# Survey: How do you build Swift?

**URL:** <https://forums.swift.org/t/survey-how-do-you-build-swift/24826>\
**Category:** Standard Library\
**Tags:** build-script, buildin-the-compiler\
**Created:** [May 24, 2019, 5:00pm UTC](https://forums.swift.org/t/survey-how-do-you-build-swift/24826 "2019-05-24T17:00:29Z")\
**Posts on this page:** 1\
**Showing post:** 28

<div class="post-metadata">

**Author:** ![DevAndArtist](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/devandartist/32/287_2.png) [@DevAndArtist](https://forums.swift.org/u/DevAndArtist)\
**Post date:** [May 26, 2019, 4:31pm UTC](https://forums.swift.org/t/survey-how-do-you-build-swift/24826/28 "2019-05-26T16:31:36Z")

</div>

I think we can append this advise from @codafi to this thread as it extends a little on how to proceed after building swift.

> [@Need a workflow advice](https://forums.swift.org/t/need-a-workflow-advice/12536/14):
>
> You absolutely do not need a toolchain to test!
> 
> You say that you have a Ninja-DebugAssert build and an Xcode-RelWithDebInfoAssert+swift-DebugAssert build, so (assuming you have a mac - you can replace the `macosx-x86_64` with the arch of your choice as long as you’ve got it built)
> 
> # Ninja-DebugAssert
> 
> ```swift
> $ cd ./build/Ninja-DebugAssert/swift-macosx-x86_64/ # Commands Assume You Run Me First!
> 
> ```
> 
> Full build
> 
> ```swift
> $ ninja
> 
> ```
> 
> Incremental build
> 
> ```swift
> $ ninja <target1> <target2> ... <targetn> # Use `ninja -t targets` to list these 
> 
> ```
> 
> Running Swift
> 
> ```swift
> $ ./bin/swift /Path/To/test.swift
> 
> ```
> 
> Getting a Development REPL
> 
> ```swift
> $ ./bin/swift
> 
> ```
> 
> ## Running Tests
> 
> ```swift
> $ cd /Path/To/Swift/Source/.. # Commands Assume You Run Me First! (Note the ..)
> 
> ```
> 
> Running All The Tests
> 
> ```swift
> $ ./llvm/utils/lit/lit.py ./build/Ninja-DebugAssert/swift-macosx-x86_64/test-macosx-x86_64/
> 
> ```
> 
> Running The Tests Without Filling Your Shell
> 
> ```swift
> $ ./llvm/utils/lit/lit.py -sv ./build/Ninja-DebugAssert/swift-macosx-x86_64/test-macosx-x86_64/
> 
> ```
> 
> Oh Crap, I Broke This Test And Need To See All The Output
> 
> ```swift
> $ ./llvm/utils/lit/lit.py -a ./build/Ninja-DebugAssert/swift-macosx-x86_64/test-macosx-x86_64/Path/To/Test.swift
> 
> ```
> 
> Oh Crap, I Broke The Validation Tests (Wait, We Have Validation Tests??)
> 
> ```swift
> $ ./llvm/utils/lit/lit.py ./build/Ninja-DebugAssert/swift-macosx-x86_64/validation-test-macosx-x86_64/
> 
> ```
> 
> Why Am I Running All These Tests, Can’t I Just Run A Subset?
> 
> ```swift
> $ ./llvm/utils/lit/lit.py ./build/Ninja-DebugAssert/swift-macosx-x86_64/test-macosx-x86_64/ --filter=<REGEX>
> 
> ```
> 
> _Caveat: Lit drops multiple --filter flags and only takes the last one_
> 
> # Writing Tests
> 
> ```swift
> $ cd /Path/To/Swift/Source/ # Commands Assume You Run Me First!
> 
> ```
> 
> _Open an existing file under `./test` . If you really can’t find one/want to play around, write one and put it in the right folder._
> 
> RUN Lines: Tell Lit what to do (they’re comments so Swiftc doesn’t barf - don’t name anything `RUN:` or `REQUIRES:` , etc. or you will have a bad time)
> 
> ```swift
> // RUN: <shell commands & Lit Substitutions>
> // RUN: <more shell commands & Lit Substitutions>
> // ...
> // RUN: etc.
> // See ./test/lit.cfg (look for config.substitutions)
> 
> ```
> 
> e.g.
> 
> ```swift
> // These Are Equivalent (Now you see why we use the substitutions)
> // RUN: %target-typecheck-verify-swift
> // RUN: /build/Ninja-ReleaseAssert/swift-macosx-x86_64/bin/swiftc -frontend -target x86_64-apple-macosx10.9 -module-cache-path '/build/Ninja-DebugAssert/swift-macosx-x86_64/swift-test-results/x86_64-apple-macosx10.9/clang-module-cache' -sdk /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.13.sdk -swift-version 3 -typecheck -verify -disable-objc-attr-requires-foundation-module /swift/test/Path/to/file.swift -module-name MyModule
> 
> ```
> 
> REQUIRES Lines: Sometimes you’ve gotta gate your test
> 
> ```swift
> // REQUIRES: objc_interop # I need Objective-C
> // REQUIRES: executable_test # Test needs to build and run a binary 
> // REQUIRES: OS=macosx # Only macOS
> // REQUIRES: CPU=x86_64 # Only Intel x86_64
> // REQUIRES: rdar777777 # I'm disabling/need to fix this test later, sorry, here's a radar number
> // See ./test/lit.cfg for more
> 
> ```

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