Build Time Optimization - Swift Bangalore #9

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1. Build time optimisation Practo Pro App Rohit Pal
 Senior iOS Engineer , Practo
3. You, after a while
4. Your manager during a critical bug fix.
5. Build time - before 0 125 250 375 500 Before 0 125 250 375 500 Before Clean Build Incremental Build 448 sec 170 sec Average
6. How we reduced the build time? Optimisation of swift code • Explicit type declaration ❌ let a = [“aab”, “b”, “c”] ✅ let a: [String] = [“aab”, “b”, “c”] • Use precomputed value ❌ if number == 30 * 30 { // do something } ✅ if number == 900 { // do something } • Avoid nil-coalescing and ternary operator (although I like to use them) • Declaring functions private or fileprivate • Declaring non inheritable classes final • Breaking complex functions
7. How we reduced the build time? Optimisation of swift code Changing few flags in build settings of Xcode Project • Build Active Architecture Only → set to YES for debug • Build Options → DEBUG INFORMATION FORMAT is set to DWARF • Swift Compiler —  OPTIMIZATION LEVEL → to -Onone • Set user defined flag to SWIFT_WHOLE_MODULE_OPTIMIZATION to YES
8. Build Time - after phase 1 0 125 250 375 500 Before After 0 125 250 375 500 Before After Clean Build Incremental Build 448 sec 278 sec 170 sec 90 sec Average
9. How did we further reduce the build time?
10. • The code was split into individual modules which were not dependent on each other. • Using tools to generate projects on demand with only the requested module. • Making it easier for the developer to generate code using these tools - written script to generate and reset the project • Tools used • XCake (Deprecated) • XcodeGen How did we further reduce the build time?
11. Build Time - Final 0 125 250 375 500 Before After Modularisation 0 125 250 375 500 Before After Modularisation Clean Build Incremental Build 448 sec 278 sec 253 sec 170 sec 90 sec 15 sec After modularisation Average
12. Build Time - Final 0 125 250 375 500 Before After Modularisation After modularisation 0 125 250 375 500 Before After Modularisation Clean Build Incremental Build 448 sec 227 sec 137 sec 170 sec 79 sec 12 sec Xcode 10 Average
13. After modularization developer productivity
14. Big shout to amazing Practo Pro iOS Team
15. Thank You! Reach out to me : Medium GitHub LinkedIn