memory layout

The concept of memory layout in Swift is discussed in the session titled "Explore Swift performance" from WWDC 2024. Memory layout refers to how values are represented in memory, which is crucial for understanding performance in Swift applications.

In Swift, every value is part of a containing context, such as local scopes, structs, classes, arrays, and dictionaries. The type of a value dictates its representation in memory, including its inline representation. For example, the inline representation of an array is a single buffer reference, which is essentially a pointer.

Swift handles memory layout and allocation dynamically when the compiler doesn't know the representation of a type at compile time. This is often the case with types like Foundation's URL, where the layout is treated as unknown at compile time. Swift can perform layout at runtime for most containers, but some containers require constant size, necessitating separate memory allocation.

For more detailed information, you can refer to the session chapter on Memory layout (10:34).