swift의 build과정을 알려줘

The build process for Swift, as discussed in the WWDC sessions, involves several key improvements and steps:

1. Explicitly Built Modules: In Xcode 16, the build process for Swift has been enhanced with the introduction of explicitly built modules. This change allows for improved parallelism, better diagnostics, and faster debugging. Explicit modules turn implicit build steps into explicit ones, which means that module builds can be performed in parallel and are clearly visible in the build log. This results in more predictable and reliable builds.

2. Build Phases: The build process is divided into three phases: scanning, building modules, and building the original code. These phases are now surfaced in the build log, providing a detailed breakdown of the build process. This helps in optimizing builds and understanding where time is being spent.

3. Parallelism and Caching: The build system can cache information between source files being scanned, which allows for better parallelism. This means that the build process can reuse binary modules, reducing the need to rebuild them from scratch each time.

4. Debugger Integration: The debugger can now share binary modules with the build, resulting in faster debugging. This is because LLDB can reuse the build outputs when evaluating expressions.

5. Enabling Explicit Modules: For Swift, explicitly built modules need to be enabled in the Xcode build settings. This can be done by selecting the project in the project navigator, going to build settings, and enabling explicitly built modules.

For more detailed information on explicitly built modules, you can refer to the session Demystify explicitly built modules (08:37).

Relevant Sessions

• What’s new in Swift (14:34)
• What’s new in Xcode 16 (06:26)
• Demystify explicitly built modules (08:37)