The document discusses techniques for optimizing Swift build times in Xcode projects. It provides several compiler flags like -debug-time-function-bodies and -warn-long-function-bodies that can profile build times. It also recommends using the Build Time Analyzer and xcprofiler tools to analyze build performance. Finally, it briefly covers updates to closures and generics in Swift that improved build times.

1. 2018/02/23

2. • 2 Swift
•
•

3. •
•
•

5. • defaults Xcode

6. • DerivedData
• +⇧+K
• +B

7. • DerivedData
• +⇧+K
• +B

9. -Xfrontend Swift compiler flags

10. [Build Settings] -> [OTHER_SWIFT_FLAGS]

11. -debug-time-function-bodies
• -Xfrontend -debug-time-function-bodies
•

12. -warn-long-function-bodies
• -Xfrontend -warn-long-function-bodies=100
• 100ms
• Swift3.0
•
• https://github.com/apple/swift/commit/
18c75928639acf0ccf0e1fb6729eea75bc09cbd5

13. -warn-long-expression-type-
checking
• -Xfrontend -warn-long-expression-type-
checking=50
• 50ms
• Xcode9 GM

16. • Swift2.2 & Xcode7.1.1
• -warn-long-function-bodies
-warn-long-expression-type-checking

17. Swift2.2+Xcode7.1.1

19. • xcodebuild
http://irace.me/swift-profiling
• Build Time Analyzer for Xcode
https://github.com/RobertGummesson/BuildTimeAnalyzer-for-Xcode
• xcprofiler

20. • xcodebuild
http://irace.me/swift-profiling
• Build Time Analyzer for Xcode
https://github.com/RobertGummesson/BuildTimeAnalyzer-for-Xcode
• xcprofiler

21. • gem install xcprofiler
• Build Settings -> Other Swift Flags
-Xfrontend -debug-time-function-bodies
•
• xcprofiler [PRODUCT_NAME or ACTIVITY_LOG_PATH]
[options]
xcprofiler

22. xcprofiler

25. 1.
Closure Generics
2.
3.Closures and lazy properties
4.Ternary Conditional Operator
5.Nil-Coalescing Operator ??

26. 1.
Closure Generics
2.
3.Closures and lazy properties
4.Ternary Conditional Operator
5.Nil-Coalescing Operator ??

31. Closure

35. Generics

40. Before

44. Before

49. https://github.com/fastred/Optimizing-Swift-
Build-Times

52. •
• 630
15
• Not Swifty
• Swift
•
•
•

53. • Swift2.2+Xcode7.1.1
Swift4+Xcode9

54. Swifty

55. Appendix
• https://developers.cyberagent.co.jp/blog/archives/7815/
• https://medium.com/@fkei/xcode
-2017-10-20 -bea6dc4f9fc0
• https://qiita.com/ruwatana/items/21b25781a2f44ccf29e2
• https://qiita.com/you_matz/items/
e95f30023eccc8d96357
• https://qiita.com/rizumita/items/913b05d799b3712260f6