What’s new in xcode build?

In the recent WWDC sessions, several updates were introduced regarding Xcode builds:

Explicit Modules: Xcode 16 and 26 have introduced explicit modules, which improve build efficiency and reliability. For C and Objective-C, explicit modules are enabled by default, while for Swift, they need to be opted in. This feature provides improved parallelism, better diagnostics, and faster debugging without changing any code. In Xcode 26, explicit modules for Swift are enabled by default, optimizing the build pipeline by splitting the processing of each compilation unit into three phases: scanning, building modules, and building the original source code. This separation allows for more precise and deterministic sharing of modules, improving build efficiency (What’s new in Xcode).
Swift Build: Apple has open-sourced Swift Build, a powerful and extensible build engine used by Xcode and Swift Playground. This engine is being incorporated into the Swift Package Manager to unify the build experience across Swift Open Source Toolchains and Xcode. It supports all platforms in the Swift ecosystem, including Linux, Windows, and Android (What’s new in Xcode).
Build System Improvements: The build system now has better control of module build tasks, optimizing the build pipeline. This results in more efficient builds and faster debugging, as the debugger can reuse already built modules (What’s new in Xcode).
Build Process and Debugging: Explicit modules make debugging faster since LLDB can reuse the build outputs when evaluating expressions. Additionally, DWARF 5 is now the default debug symbol format, which results in smaller DSIM bundles and faster symbol lookups (What’s new in Xcode 16).

These updates aim to enhance the efficiency, reliability, and speed of the build process in Xcode, making it easier for developers to manage and optimize their projects.