Swift Source Code

The code for the Swift project is divided into several open-source repositories, all hosted on GitHub.

Compiler and Standard Library

The main Swift repository, which contains the source code for the Swift compiler, standard library, and SourceKit.
Documents related to the continued evolution of Swift, including goals for upcoming releases proposals for changes to and extensions of Swift.

Directions for building the Swift compiler and standard library, along with its prerequisites, are provided by the main Swift repository’s README file.

Core Libraries

The source code for Foundation, which provides common functionality for all applications.
The source code for libdispatch, which provides concurrency primitives for working on multicore hardware.
The source code for XCTest, which provides fundamental testing infrastructure for Swift apps and libraries.

Package Manager

The source code for the Swift package manager.
The source code for llbuild, a low-level build system used by the Swift package manager.
Contains common infrastructural code for both SwiftPM and llbuild.

Xcode Playground Support

The source code to enable playground integration with Xcode.

Cloned Repositories

Swift builds upon several other open-source projects, most notably the LLVM Compiler Infrastructure. Swift’s clones of the repositories of those open-source projects contain Swift-specific changes and are merged regularly from their upstream sources. 

The source code for LLVM, with a handful of Swift-specific additions. Merged regularly from the LLVM sources at llvm.org.
The source code for Clang, with a handful of Swift-specific additions. Merged regularly from the Clang sources at llvm.org.
The source code for the Swift-enabled version of LLDB, for debugging Swift programs. Merged regularly from the LLDB sources at llvm.org.
The source code for CommonMark, which is used in the Swift compiler.
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