Bug 40777: Create a Go bootstrap project

Merge Info

Related Issues

• #40777 (closed)

Backport Timeline

• Immediate - patchsets for critical bug fixes or other major blocker (e.g. fixes for a 0-day exploit) OR patchsets with trivial changes which do not need testing (e.g. fixes for typos or fixes easily verified in a local developer build)
• Next Minor Stable Release - patchset that needs to be verified in nightly before backport
• Eventually - patchset that needs to be verified in alpha before backport
• No Backport - patchset for the next major stable

Issue Tracking

• Link resolved issues with appropriate Release Prep issue for changelog generation

Change Description

We've talked about getting a Go bootstrap project for a while now.

The last changes on the dependency management inspired me to finally do it.

Also, the new target_replace option is very useful to build the bootstrapper only for Linux.

Please notice that the old Go project didn't use the custom GCC we build, so I continued not doing so.
The reason was probably that the original Go 1.4 didn't play well with more recent compilers, but I switched to a revised 1.4 that has been updated just for bootstrapping (see Go's doc).
So, we could switch to our compiler, if we think it's better.

projects/go/0001-Use-fixed-go-build-tmp-directory.patch

-From 958f724b1b434702c3d44ceaca646791674d07b1 Mon Sep 17 00:00:00 2001
+From 2c1c98d6404284df744a194dd23bd3660f365387 Mon Sep 17 00:00:00 2001
 From: Georg Koppen <gk@torproject.org>
 Date: Fri, 17 Apr 2020 10:24:23 +0000
 Subject: [PATCH] Use fixed go-build tmp directory
@@ -6,15 +6,18 @@ Subject: [PATCH] Use fixed go-build tmp directory
 Use fixed go-build tmp directory, when the directory does not exist, in
 order to avoid some reproducibility issues where build directory gets
 embedded in generated binaries.
+---
+ src/cmd/go/internal/work/action.go | 10 +++++++---
+ 1 file changed, 7 insertions(+), 3 deletions(-)
 
 diff --git a/src/cmd/go/internal/work/action.go b/src/cmd/go/internal/work/action.go
-index 33b7818fb2..5e369d0f53 100644
+index 8beb1345d0..dccf39c1c1 100644
 --- a/src/cmd/go/internal/work/action.go
 +++ b/src/cmd/go/internal/work/action.go
-@@ -252,9 +252,13 @@ func (b *Builder) Init() {
- 	if cfg.BuildN {
- 		b.WorkDir = "$WORK"
- 	} else {
+@@ -279,9 +279,13 @@ func NewBuilder(workDir string) *Builder {
+ 		if !buildInitStarted {
+ 			panic("internal error: NewBuilder called before BuildInit")
+ 		}
 -		tmp, err := os.MkdirTemp(cfg.Getenv("GOTMPDIR"), "go-build")
 -		if err != nil {
 -			base.Fatalf("go: creating work dir: %v", err)
@@ -29,5 +32,5 @@ index 33b7818fb2..5e369d0f53 100644
  		if !filepath.IsAbs(tmp) {
  			abs, err := filepath.Abs(tmp)
 -- 
-2.26.1
+2.39.2