编译 Swift 5.8 源码

发表于 2023-04-08 分类于底层原理 Disqus：

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：

名称	版本
芯片	Apple M2 Pro
macOS	Ventura 13.3
Python	3.11.2
CMake	3.26.3
ninja	1.11.1
sccache	0.4.1
Xcode	14.3

我们可以通过 homebrew 统一安装环境：

1	$ 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：

1 2	$ 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：

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

终端运行命令查看 xcrun swift -version。

本地环境输出如下：

1 2	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：

1 2	$ 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

1	$ 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