Crash logs are not supposed to be cryptic. Yet every Swift developer has stared at a stack frame like _$s9MyAppName10DetailViewV4bodyQrvg and felt the distinct urge to close the laptop and take up pottery. That string is not noise. It is a mangled Swift symbol, and swift-demangle is the tool that turns it back into something
Swift was designed to be a practical language for Apple platforms, but it did not arrive in a vacuum. The system frameworks underneath iOS, macOS, watchOS, and tvOS are still largely C and Objective-C. When you call DispatchQueue, read a stat structure, or talk to a POSIX socket, you are crossing a language boundary. Swift
The Performance Regression You Didn’t Profile For Last quarter, a team I was advising shipped what looked like an innocent feature: a local cache of Document structs, each containing an array of Section structs, each containing an array of Paragraph structs. Three layers of value types, each with its own Array storage. The team assumed
Profiling a Swift app means measuring where your code actually spends time, memory, energy, and I/O, then using that evidence to make targeted changes. It sits next to related disciplines like benchmarking, tracing, and performance regression testing. If you ship production iOS, macOS, watchOS, or tvOS apps, profiling isn’t a final polish step. It’s how
