From 4d43f7c4dd06e6f62be446996019d4505af54764 Mon Sep 17 00:00:00 2001
From: Christian Stewart <christian@paral.in>
Date: Thu, 14 Apr 2022 13:34:26 -0700
Subject: [PATCH] build: bootstrap: set environment before generating buildcfg

The GOOS and GOARCH environment variables should be unset before calling
mkbuildcfg. This change fixes a build failure when GOARCH=riscv64.

Building Go toolchain1 using go-1.4-bootstrap-20171003.
src/cmd/compile/internal/ssa/rewriteRISCV64.go:4814
invalid operation: y << x (shift count type int64, must be unsigned integer)

There is a build issue with go1.4 with the riscv64 code: however, why is the
riscv64 code being compiled at all?

GOARCH is set when calling mkbuildcfg, so go1.4 is trying to compile riscv64.

[Buildroot]: submitted to upstream:

 - https://github.com/golang/go/issues/52583
 - https://go-review.googlesource.com/c/go/+/400376
 - GitHub-Pull-Request: golang/go#52362

Signed-off-by: Christian Stewart <christian@paral.in>
---
 src/cmd/dist/buildtool.go | 56 ++++++++++++++++++++-------------------
 1 file changed, 29 insertions(+), 27 deletions(-)

diff --git a/src/cmd/dist/buildtool.go b/src/cmd/dist/buildtool.go
index f1f3d50b6f..dabf01cf84 100644
--- a/src/cmd/dist/buildtool.go
+++ b/src/cmd/dist/buildtool.go
@@ -116,9 +116,6 @@ func bootstrapBuildTools() {
 	}
 	xprintf("Building Go toolchain1 using %s.\n", goroot_bootstrap)
 
-	mkbuildcfg(pathf("%s/src/internal/buildcfg/zbootstrap.go", goroot))
-	mkobjabi(pathf("%s/src/cmd/internal/objabi/zbootstrap.go", goroot))
-
 	// Use $GOROOT/pkg/bootstrap as the bootstrap workspace root.
 	// We use a subdirectory of $GOROOT/pkg because that's the
 	// space within $GOROOT where we store all generated objects.
@@ -130,6 +127,34 @@ func bootstrapBuildTools() {
 	base := pathf("%s/src/bootstrap", workspace)
 	xmkdirall(base)
 
+	// Set up environment for invoking Go 1.4 go command.
+	// GOROOT points at Go 1.4 GOROOT,
+	// GOPATH points at our bootstrap workspace,
+	// GOBIN is empty, so that binaries are installed to GOPATH/bin,
+	// and GOOS, GOHOSTOS, GOARCH, and GOHOSTOS are empty,
+	// so that Go 1.4 builds whatever kind of binary it knows how to build.
+	// Restore GOROOT, GOPATH, and GOBIN when done.
+	// Don't bother with GOOS, GOHOSTOS, GOARCH, and GOHOSTARCH,
+	// because setup will take care of those when bootstrapBuildTools returns.
+
+	defer os.Setenv("GOROOT", os.Getenv("GOROOT"))
+	os.Setenv("GOROOT", goroot_bootstrap)
+
+	defer os.Setenv("GOPATH", os.Getenv("GOPATH"))
+	os.Setenv("GOPATH", workspace)
+
+	defer os.Setenv("GOBIN", os.Getenv("GOBIN"))
+	os.Setenv("GOBIN", "")
+
+	os.Setenv("GOOS", "")
+	os.Setenv("GOHOSTOS", "")
+	os.Setenv("GOARCH", "")
+	os.Setenv("GOHOSTARCH", "")
+
+	// Create the build config files.
+	mkbuildcfg(pathf("%s/src/internal/buildcfg/zbootstrap.go", goroot))
+	mkobjabi(pathf("%s/src/cmd/internal/objabi/zbootstrap.go", goroot))
+
 	// Copy source code into $GOROOT/pkg/bootstrap and rewrite import paths.
 	writefile("module bootstrap\n", pathf("%s/%s", base, "go.mod"), 0)
 	for _, dir := range bootstrapDirs {
@@ -176,30 +201,6 @@ func bootstrapBuildTools() {
 		})
 	}
 
-	// Set up environment for invoking Go 1.4 go command.
-	// GOROOT points at Go 1.4 GOROOT,
-	// GOPATH points at our bootstrap workspace,
-	// GOBIN is empty, so that binaries are installed to GOPATH/bin,
-	// and GOOS, GOHOSTOS, GOARCH, and GOHOSTOS are empty,
-	// so that Go 1.4 builds whatever kind of binary it knows how to build.
-	// Restore GOROOT, GOPATH, and GOBIN when done.
-	// Don't bother with GOOS, GOHOSTOS, GOARCH, and GOHOSTARCH,
-	// because setup will take care of those when bootstrapBuildTools returns.
-
-	defer os.Setenv("GOROOT", os.Getenv("GOROOT"))
-	os.Setenv("GOROOT", goroot_bootstrap)
-
-	defer os.Setenv("GOPATH", os.Getenv("GOPATH"))
-	os.Setenv("GOPATH", workspace)
-
-	defer os.Setenv("GOBIN", os.Getenv("GOBIN"))
-	os.Setenv("GOBIN", "")
-
-	os.Setenv("GOOS", "")
-	os.Setenv("GOHOSTOS", "")
-	os.Setenv("GOARCH", "")
-	os.Setenv("GOHOSTARCH", "")
-
 	// Run Go 1.4 to build binaries. Use -gcflags=-l to disable inlining to
 	// workaround bugs in Go 1.4's compiler. See discussion thread:
 	// https://groups.google.com/d/msg/golang-dev/Ss7mCKsvk8w/Gsq7VYI0AwAJ
@@ -221,6 +222,7 @@ func bootstrapBuildTools() {
 		cmd = append(cmd, "-toolexec="+tool)
 	}
 	cmd = append(cmd, "bootstrap/cmd/...")
+
 	run(base, ShowOutput|CheckExit, cmd...)
 
 	// Copy binaries into tool binary directory.
-- 
2.35.1