工具

vscode

clone仓库

git clone https://github.com/golang/go
cd golang/go
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编译go

编译的主要入口是src/make.bash(windows则是src/make.bat):

# src/make.bash

# GOROOT_FINAL: The expected final Go root, baked into binaries.
# The default is the location of the Go tree during the build.
#
# GOROOT_BOOTSTRAP: A working Go tree >= Go 1.4 for bootstrap.
# If $GOROOT_BOOTSTRAP/bin/go is missing, $(go env GOROOT) is
# tried for all "go" in $PATH. $HOME/go1.4 by default.
if [ ! -f run.bash ]; then
	echo 'make.bash must be run from $GOROOT/src' 1>&2
	exit 1
fi
...
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有两个环境变量值得注意：

• GOROOT_FINAL 最终输出的编译的go的目录
• GOROOT_BOOTSTRAP 用于编译go的基础go版本，必须>=go1.4

必须在src目录运行make.bash。

cd src
rm -rf build_go && mkdir -p build_go
GOROOT_FINAL=build_go ./make.bash
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日志:

Building Go cmd/dist using /Users/xhd2015/installed/go1.17. (go1.17.5 darwin/amd64)
Building Go toolchain1 using /Users/xhd2015/installed/go1.17.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
Building Go toolchain2 using go_bootstrap and Go toolchain1.
Building Go toolchain3 using go_bootstrap and Go toolchain2.
Building packages and commands for darwin/amd64.
---
Installed Go for darwin/amd64 in /Users/xhd2015/Projects/gopath/src/github.com/golang/go
Installed commands in /Users/xhd2015/Projects/gopath/src/github.com/golang/go/bin

The binaries expect /Users/xhd2015/Projects/gopath/src/github.com/golang/go to be copied or moved to build_go
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运行编译完成的go;

$ GOROOT=$PWD bin/go version
go version devel go1.19-416c953960 Sun Jun 26 00:26:59 2022 +0000 darwin/amd64
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误区1: 直接调试 src/cmd/go

虽然src/cmd/go能够编译成go，但是如果直接使用系统的工具编译:

cd src/cmd
go build -o cmd_go ./go
./cmd_go # 这里实际是以系统的源码进行编译的
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必须使用src/make.bash才能编译出当前目录的go。

调试src/cmd/go

GOROOT=../.. ../../bin/go build -gcflags=all="-N -l" -o /tmp/go/cmd/cmd_go.bin ./go
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IDE

vscode需要设置go.goroot:

  "go.goroot": "/Users/xhd2015/Projects/gopath/src/github.com/golang/go",
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并重启。这样才能解析到对应的符号。