Swift-At-Scale-v3.pdf

Transcript

1. Swift at scale tgebarowski (v3 revised) Tomasz Gebarowski Mobile Warsaw 24.07.2017
2. mBank.pl tgebarowski
3. tgebarowski
4. some stats +10 developers 2 years of development +3200 Swift files 100’s of View Controllers, Cells We use code generation 3 migrations between Swift versions tgebarowski
5. scale effect compilation times migrations tgebarowski
6. compilation times https://xkcd.com/303/ tgebarowski
7. 1 minute? tgebarowski
8. 5 minutes? tgebarowski
9. up to 40 minutes… tgebarowski
10. https://github.com/riamf/XcodeBuildTimeMeasurement Day time (s) formatted time no builds 10.10.2016 7297 2h 1m 37s 24 11.10.2016 12221 3h 23m 41s 87 12.10.2016 7146 1h 59m 5s 79 13.10.2016 8885 2h 28m 5s 107 14.10.2016 4452 1h 14m 12s 33 tgebarowski
11. Compilation times -Onone -whole-module- optimization Core i5 ~40 min ~11 min Core i7 ~30 min ~8 min tgebarowski
12. Why -Onone is so slow? In a large project, single Swift file compilation takes ~1 second
13. Why -Onone is so slow? -filelist argument contains a list of all Swift files in a project
14. specialisation of generic functions for concrete types inlining dead function/method elimination source: swift.org whole-module optimization tgebarowski
15. single invocation of frontend with -filelist argument whole-module optimization tgebarowski
16. could it be faster? tgebarowski
17. compilation times -Onone -whole-module- optimization SWIFT_WHOLE_MODULE_ OPTIMIZATION=YES Core i5 ~40 min ~11 min ~5 min Core i7 ~30 min ~8 min ~3 min tgebarowski
18. swift -frontend -primary-file file1.swift -filelist file swift -whole-module-optimization file1.swift file2.swift file3.swift how it works? swift -Onone file1.swift file2.swift file3.swift swift -frontend -whole-module-optimization -filelist file swift -frontend -primary-file file2.swift -filelist file swift -frontend -primary-file file3.swift -filelist file spawn spawn spawn spawn -whole-module-optimization -Onone tgebarowski
19. swift -whole-module-optimization file1.swift file2.swift file3.swift the trick swift -frontend -whole-module-optimization -Onone -filelist file spawn SWIFT_WHOLE_MODULE_OPTIMIZATION=YES tgebarowski
20. Xcode 9 tgebarowski
21. SWIFT_WHOLE_MODULE_OPTIMIZATION=YES still works tgebarowski
22. what about? tgebarowski
23. what about? nothing changed…
24. beware of large targets! getconf ARG_MAX 262144 uses absolute path of every Swift file in project +1500 Swift files Assume long project dir path MacOS command line
 max length tgebarowski
25. Frameworks! One Monolithic Mobile App MBFoundation MBServiceKit MBUtilityKit MBCoreKit MBGlueKit MobileApp dropping iOS 7 support tgebarowski
26. -Onone -Owholemodule Core i5 ~18 min
 ~40 min ~10 min
 ~11 min Core i7 13 min
 ~30 min 8 min
 ~8 min compilation times after introducing frameworks tgebarowski
27. Migrations Swift 1.2 Swift 2.1 Swift 2.2 2 days ~3 weeks author: Christophe Boisson Swift 3 7 days tgebarowski
28. Swift 1.2 Swift 2.1 ~3 weeks Swift 2.2 Swift 3 7 days 8h Migration Tool 2 days Manual Fixes 2 devs 5 days Bypassing 
 compiler bug 3h Migration Tool 4 days Manual Fixes 3 devs ~3800 errors ~1600 errors 5 days Regression testing 2 days Regression testing
29. migration process Auto migration Code Freeze Migrating Core frameworks Migrating App itself Migrating Unit and UI tests Regression and fixing issues Auto migration Migrating Core frameworks Estimating number and types of bugs to fix migration evaluation migration process tgebarowski
30. Swift 3 Migration Issues • dequeueReusableCellWithIdentifier -> dequeueReusableCell(withIdentifier:for:) • hidden -> isHidden • enabled -> isEnabled • popViewControllerAnimated -> popViewController(animated:) • registerNib(_:forCellReuseIdentifier:) -> register(_:forCellReuseIdentifier:) • wszystkie błędy związane z rename’ing enumów ‚X’ has been renamed to ‚Y’ 551 errors extraneous argument label 250 errors explicitly marked unavailable here 570 errors has no case „X”, did you mean „x” 523 errors NSDate & Date related 114 errors tgebarowski
31. The +1500 Swift files problem (Xcode 7.2) swiftc crash Migration Issues tgebarowski
32. swift -frontend swiftc swift -frontend posix_spawn swift -frontend … crash The +1500 Swift files problem (Xcode 7.2) tgebarowski
33. Reported problem to Apple (SR-280) Fixed in Xcode 7.3 Provided a workaround for 7.2 swiftc wrapper swiftc -num-threads 0 with fork instead of posix_spawn Xcode More info: https://github.com/tgebarowski/swiftc-wrapper The +1500 Swift files problem (Xcode 7.2) tgebarowski
34. What’s next? tgebarowski
35. • Swift 4 • Xcode 9 • precompiled frameworks • static libraries • Buck What’s next? tgebarowski
36. Thank You! tgebarowski
37. tgebarowski Swift at scale Tomasz Gebarowski Mobile Warsaw 24.07.2017