编译 Swift 5.8 源码

Table of contents

编译准备

首先保证硬盘空间足够，本人一套流程下来文件夹有将近 60GB 大小。接下来是相关环境的安装，因为我的环境都是最新的，所以基本安装的都是最新版的包，如果你的环境不是新版的话，请找对应版本包安装。本人环境说明：

我们可以通过 homebrew 统一安装环境：

$ brew install cmake ninja sccache

此文只介绍 Xcode 调试环境，如果想用 VS Code 调试的话，需要用 Ninja 编译，Ninja 的编译请移步官方文档。

项目拉取

首先我们在文稿中新建一个文件夹，然后 cd 到我们的目录：

$ mkdir ~/Documents/swift-project
$ cd ~/Documents/swift-project

然后找到你的 Xcode 所支持的 Swift 版本，因为本人的 Xcode 为 14.3 版本，所以直接下载 Swift 5.8 Release。查找 Xcode 对应的 Swift 的版本有两种方式：

1. 去官网，查看 Xcode 的 Release Notes，在 Overview 中会有介绍。例如：Xcode 14.3 Release Notes

2. 终端运行命令查看 xcrun swift -version。

   本地环境输出如下：

   swift-driver version: 1.75.2 Apple Swift version 5.8 (swiftlang-5.8.0.124.2 clang-1403.0.22.11.100)
   Target: arm64-apple-macosx13.0

我们在刚才新建的目录中执行如下命令拉取对应的 Swift 源码，并 cd 到源码目录：

$ git clone --branch swift-5.8-RELEASE git@github.com:apple/swift.git
$ cd swift

拉取源码后还须拉取依赖

$ utils/update-checkout --tag swift-5.8-RELEASE --clone

顺便说一句，上述操作最好全程科学上网。

编译

一切准备完毕后我们将开始第一步编译，这里我们需要用到官方的脚本，在 utils 目录下的 build-script 脚本，以下是本人所使用的命令。

$ utils/build-script \
--release-debuginfo --debug-swift-stdlib \
--xcode --skip-ios --skip-watchos --skip-tvos \
--skip-early-swiftsyntax --swift-darwin-supported-archs="$(uname -m)"

编译命令的参数最好做一些简单了解，不要盲目复制粘贴，这里只展示苹果 M 系列芯片的 arm64 架构编译命令，如果你是 Intel 环境请自行查阅官方文档。或执行 utils/build-script --help 命令查阅。

我们来简单的介绍一下这里众多的参数：

• --release-debuginfo 编译出带有 RelWithDebInfo 环境变量的工程，类似于 Debug 和 Release 模式，RelWithDebInfo 会优化一部分，但同时保留调试信息。

• --debug-swift-stdlib 编译带有调试信息的 Swift标准库，如果想调试 Swift编译器，可以使用 --debug-swift。

• --xcode 使用 CMake 的 Xcode 生成器，编译完成后会生成一个 Swift.xcodeproj 工程。

• --skip-ios --skip-watchos --skip-tvos 跳过相应平台，这里只编译 macOS 平台。

• --swift-darwin-supported-archs="$(uname -m)" 编译相关架构，$(uname -m) 命令用于获取机器架构环境，例如本机获取的结果为 arm64。

--skip-early-swiftsyntax 这个命令我们留到后面错误修复的时候再说，这里先留个悬念。

接下来我们回车执行命令，这里需要等待一段时间，编译时间长短与机器性能有关。编译结束之后，我们会在目录 ~/Documents/swift-project 下得到一个 build 文件夹，里面就是我们 build 的产物。

Xcode-RelWithDebInfoAssert+stdlib-DebugAssert。目录结构如下图：

至此第一阶段编译完成，离成功又近了一步，接下来我们进入 Xcode 编译阶段。

源码调试

进入目录 swift-macosx-arm64 双击打开 Xcode 工程，此时会有自动创建 schemes 的提示，如下图，我们选择自动创建。

创建自定义 target 用于调试

在 Swift.xcodeproj 工程里面，我们点击 TARGETS 下面的 + 新建一个调试的 target，我们选择 macOS 的命令行模式。如下图：

Product Name 取个自定义名字就行。接下来为我们的 target 引入依赖，如下图：

接下来我们需要在设置中关闭 Hardened Runtime 选项，如下图：

如果想了解更多关于 Hardened Runtime 的介绍，请查看官方文档：Hardened Runtime。

我们还须将 target scheme 的 Build Configuration 修改为 ReWithDebInfo。

最后我们在自定义 target 文件夹下的 main.swift 文件中添加相应的代码，并在 HeapObject.cpp 中设置断点就可以开始愉快的调试了。如下图：

问题解决

在编译源码的过程中，本人遇到了几个问题，列在这里用以记录，也方便他人。

执行脚本阶段，最开始我执行的脚本并没有添加 --skip-early-swiftsyntax 这两个参数，脚本执行不通过，报错如下：

CMake Error in lib/ASTGen/CMakeLists.txt:
  Imported target "SwiftSyntax::SwiftBasicFormat" includes non-existent path

    "/Users/jiafengwu/Documents/github/buildSwiftSource/build/Xcode-RelWithDebInfoAssert+stdlib-DebugAssert/earlyswiftsyntax-macosx-arm64/lib/swift/host"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
    provide.



CMake Error in lib/ASTGen/CMakeLists.txt:
  Imported target "SwiftSyntax::SwiftBasicFormat" includes non-existent path

    "/Users/jiafengwu/Documents/github/buildSwiftSource/build/Xcode-RelWithDebInfoAssert+stdlib-DebugAssert/earlyswiftsyntax-macosx-arm64/lib/swift/host"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
    provide.



CMake Error in lib/ASTGen/CMakeLists.txt:
  Imported target "SwiftSyntax::SwiftBasicFormat" includes non-existent path

    "/Users/jiafengwu/Documents/github/buildSwiftSource/build/Xcode-RelWithDebInfoAssert+stdlib-DebugAssert/earlyswiftsyntax-macosx-arm64/lib/swift/host"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
    provide.



CMake Error in lib/ASTGen/CMakeLists.txt:
  Imported target "SwiftSyntax::SwiftBasicFormat" includes non-existent path

    "/Users/jiafengwu/Documents/github/buildSwiftSource/build/Xcode-RelWithDebInfoAssert+stdlib-DebugAssert/earlyswiftsyntax-macosx-arm64/lib/swift/host"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
    provide.



CMake Error in lib/Parse/CMakeLists.txt:
  Imported target "SwiftSyntax::SwiftBasicFormat" includes non-existent path

    "/Users/jiafengwu/Documents/github/buildSwiftSource/build/Xcode-RelWithDebInfoAssert+stdlib-DebugAssert/earlyswiftsyntax-macosx-arm64/lib/swift/host"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
    provide.



CMake Error in lib/Parse/CMakeLists.txt:
  Imported target "SwiftSyntax::SwiftBasicFormat" includes non-existent path

    "/Users/jiafengwu/Documents/github/buildSwiftSource/build/Xcode-RelWithDebInfoAssert+stdlib-DebugAssert/earlyswiftsyntax-macosx-arm64/lib/swift/host"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
    provide.



CMake Error in lib/Parse/CMakeLists.txt:
  Imported target "SwiftSyntax::SwiftBasicFormat" includes non-existent path

    "/Users/jiafengwu/Documents/github/buildSwiftSource/build/Xcode-RelWithDebInfoAssert+stdlib-DebugAssert/earlyswiftsyntax-macosx-arm64/lib/swift/host"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
    provide.



CMake Error in lib/Parse/CMakeLists.txt:
  Imported target "SwiftSyntax::SwiftBasicFormat" includes non-existent path

    "/Users/jiafengwu/Documents/github/buildSwiftSource/build/Xcode-RelWithDebInfoAssert+stdlib-DebugAssert/earlyswiftsyntax-macosx-arm64/lib/swift/host"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

  * The path was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
    provide.

从上面的报错可看出，出错的原因是在编译 earlyswiftsyntax 的时候。要修复此问题，我们只需添加参数 --skip-early-swiftsyntax 即可，让其在执行编译命令的时候跳过 earlyswiftsyntax 的构建。因为这并不影响我们最终的源码调试。

Xcode 编译阶段，第一次执行编译的时候出现了如下的错误：

这是由于在执行 utils/build-script --xcode 的时候 cxxshim 试图创建模块目录导致。我们只需要将 swift/stdlib/public/Cxx/cxxshim/CMakeLists.txt 此文件中的如下命令删除即可：

list(APPEND outputs ${module_dir})
if(SWIFT_BUILD_STATIC_STDLIB)
  list(APPEND outputs ${module_dir_static})
endif()

然后清空 build 目录，重新执行 utils/build-script 进行构建即可。

接下来一切完成后，继续 Xcode 编译又会出现如下错误:

看报错是 llvm-macosx-arm64 中的 Debug 目录下没有相应的文件。首先我们查看 swift-compatibility-symbols 这个 target 将其 Build Configuration 修改为 ReWithDebInfo 。然后我们在执行编译即可。

参考文档

• How to Set Up an Edit-Build-Test-Debug Loop
• Bootstrapping broken for Ninja builds on Apple silicon Macs (arm64)
• Problems with build-script building compiler with –xcode
• Fix multiple commands produce ${SWIFTLIB_DIR}/${arch_subdir}
• CMake error when running build-script with --xcode
• Swift源码编译调试(M1/Xcode)
• 超实用～使用Xcode编译Swift源码