Why executable files is separated in a bundle of an app from Xcode 16 ?

In Xcode 16, executable files are separated in a bundle of an app due to the introduction of explicitly built modules. This change brings several benefits:

1. Improved Parallelism: Explicitly built modules allow for more parallelism during the build process. This means that different parts of the build can proceed simultaneously without waiting for modules to be implicitly built, leading to faster builds.

2. Better Diagnostics: With explicitly built modules, the build system is fully aware of the module graph. This awareness allows for more informed scheduling choices and better diagnostics, making it easier to identify and resolve build issues.

3. Faster Debugging: The debugger can now share binary modules with the build, which results in faster debugging. This avoids the need for the debugger to build its own version of the modules, reducing long pauses when first printing variables.

4. Predictable and Reliable Builds: Explicitly built modules turn implicit steps into explicit build steps, making the build process more predictable and reliable. This also helps in optimizing the build process by clearly showing where time is being spent.

For more details, you can refer to the session Demystify explicitly built modules (04:58).

Relevant Sessions

1. What’s new in Xcode 16 (06:26)
2. Demystify explicitly built modules (03:57)
3. What’s new in Swift (14:34)