Xcode Build Settings Checker
Find the settings slowing down your builds.
Paste your build settings. They're checked in your browser and never uploaded.
1. Export your settings
Run this in your project folder, then copy the output. Use -workspace instead of -project if you have one.
2. Paste them here
The output of xcodebuild -showBuildSettings, or the contents of an .xcconfig file.
Results
What makes Debug builds slow?
Whole module compilation
In Release, compiling a Swift module as a whole lets the optimiser see everything. In Debug it means a one-line change recompiles the entire module. Debug should use Incremental (singlefile).
Building every architecture
With ONLY_ACTIVE_ARCH = NO, a Debug build compiles for both Apple silicon and Intel (or every simulator architecture), roughly doubling the work for builds you only run on one machine.
dSYMs on every build
dwarf-with-dsym runs dsymutil after linking. You need dSYMs to symbolicate crash reports from Release builds, not for builds you run from Xcode.
Slow type checking
One complicated expression can take seconds to type-check. Adding -Xfrontend -warn-long-function-bodies=200 and -Xfrontend -warn-long-expression-type-checking=200 to Other Swift Flags in Debug makes Xcode warn you about any function or expression that takes longer than 200 ms.
