dashboard: add new Windows ARM builder

This partially reverts CL 229559, while adjusting it to use a new
builder. The builder will be used now for windows/arm and later for
windows/arm64.

Updates golang/go#42604.
Updates golang/go#38607.
Updates golang/go#36439.

Change-Id: I1ab661a6585e64de8196955c077715b32dc732b8
Reviewed-on: https://go-review.googlesource.com/c/build/+/272106
Run-TryBot: Jason A. Donenfeld <[email protected]>
TryBot-Result: Go Bot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Trust: Alex Brainman <[email protected]>
Trust: Jason A. Donenfeld <[email protected]>

Author: zx2c4

cmd/buildlet/Makefile

@@ -35,7 +35,7 @@ compile:
 	GOOS=windows GOARCH=amd64 go install golang.org/x/build/cmd/buildlet
 
 # buildlet.all is compiles & uploads all targets.
-buildlet.all: FORCE buildlet.aix-ppc64 buildlet.darwin-amd64 buildlet.freebsd-amd64 buildlet.linux-amd64 buildlet.netbsd-386 buildlet.netbsd-amd64 buildlet.netbsd-arm buildlet.openbsd-amd64.go1.10 buildlet.openbsd-386.go1.10 buildlet.openbsd-amd64 buildlet.openbsd-386 buildlet.plan9-386 buildlet.windows-amd64 buildlet.linux-arm buildlet.linux-arm-arm5 buildlet.linux-arm64 buildlet.linux-riscv64 buildlet.linux-mips buildlet.linux-mipsle buildlet.linux-mips64 buildlet.linux-mips64le buildlet.linux-ppc64 buildlet.linux-ppc64le buildlet.linux-s390x buildlet.solaris-amd64 buildlet.illumos-amd64
+buildlet.all: FORCE buildlet.aix-ppc64 buildlet.darwin-amd64 buildlet.freebsd-amd64 buildlet.linux-amd64 buildlet.netbsd-386 buildlet.netbsd-amd64 buildlet.netbsd-arm buildlet.openbsd-amd64.go1.10 buildlet.openbsd-386.go1.10 buildlet.openbsd-amd64 buildlet.openbsd-386 buildlet.plan9-386 buildlet.windows-amd64 buildlet.windows-arm buildlet.linux-arm buildlet.linux-arm-arm5 buildlet.linux-arm64 buildlet.linux-riscv64 buildlet.linux-mips buildlet.linux-mipsle buildlet.linux-mips64 buildlet.linux-mips64le buildlet.linux-ppc64 buildlet.linux-ppc64le buildlet.linux-s390x buildlet.solaris-amd64 buildlet.illumos-amd64
 	echo "done"
 
 buildlet.aix-ppc64: FORCE
@@ -120,6 +120,10 @@ buildlet.windows-386: FORCE buildlet_windows.go
 	go install golang.org/x/build/cmd/upload
 	upload --verbose --osarch=$@ --file=go:golang.org/x/build/cmd/buildlet --public --cacheable=false go-builder-data/$@
 
+buildlet.windows-arm: FORCE buildlet_windows.go
+	go install golang.org/x/build/cmd/upload
+	upload --verbose --osarch=$@ --file=go:golang.org/x/build/cmd/buildlet --public --cacheable=false go-builder-data/$@
+
 buildlet.linux-arm: FORCE
 	go install golang.org/x/build/cmd/upload
 	upload --verbose --osarch=$@ --file=go:golang.org/x/build/cmd/buildlet --public --cacheable=false go-builder-data/$@

dashboard/builders.go

@@ -94,6 +94,7 @@ var slowBotAliases = map[string]string{
 	"windows":        "windows-amd64-2016",
 	"windows-386":    "windows-386-2008",
 	"windows-amd64":  "windows-amd64-2016",
+	"windows-arm":    "windows-arm-zx2c4",
 }
 
 // Builders are the different build configurations.
@@ -457,6 +458,12 @@ var Hosts = map[string]*HostConfig{
 		goBootstrapURLTmpl: "https://storage.googleapis.com/$BUCKET/go1.4-windows-amd64.tar.gz",
 		SSHUsername:        "gopher",
 	},
+	"host-windows-arm64-zx2c4": &HostConfig{
+		IsReverse:   true,
+		ExpectNum:   1,
+		OwnerGithub: "zx2c4",
+		env:         []string{"GOROOT_BOOTSTRAP=C:\\Program Files (Arm)\\Go"},
+	},
 	"host-darwin-10_11": &HostConfig{
 		IsReverse: true,
 		ExpectNum: 3,
@@ -1614,8 +1621,8 @@ func init() {
 	addMiscCompile("-netbsd", "^netbsd-")                    // 4: amd64, 386, arm, arm64
 	addMiscCompile("-openbsd", "^openbsd-")                  // 4: amd64, 386, arm, arm64
 
-	// And 3 that don't fit above:
-	addMiscCompile("-other", "^(linux-s390x|linux-riscv64|dragonfly-amd64)$")
+	// And 4 that don't fit above:
+	addMiscCompile("-other", "^(windows-arm|linux-s390x|linux-riscv64|dragonfly-amd64)$")
 
 	// TODO: Issue 25963, get the misc-compile trybots for Android/iOS.
 	// Then consider subrepos too, so "mobile" can at least be included
@@ -2174,6 +2181,14 @@ func init() {
 			// up:
 			"GO_TEST_TIMEOUT_SCALE=2"},
 	})
+	addBuilder(BuildConfig{
+		Name:       "windows-arm-zx2c4",
+		HostType:   "host-windows-arm64-zx2c4",
+		KnownIssue: 38607, // TODO: remove this after this builder has proved it works
+		env: []string{
+			"GOARM=7",
+			"GO_TEST_TIMEOUT_SCALE=2"},
+	})
 	addBuilder(BuildConfig{
 		Name:     "darwin-amd64-10_11",
 		HostType: "host-darwin-10_11",

dashboard/builders_test.go

@@ -755,7 +755,6 @@ func TestSlowBotAliases(t *testing.T) {
 	ports := strings.Fields(string(out))
 
 	done := map[string]bool{}
-	done["windows-arm"] = true // TODO(golang.org/issue/38607) disabled until builder is replaced
 
 	var add bytes.Buffer
 	check := func(term string, isArch bool) {
@@ -826,7 +825,6 @@ func TestTryBotsCompileAllPorts(t *testing.T) {
 
 	done := map[string]bool{}
 	done["darwin-arm"] = true   // TODO: Remove when Go 1.16 is out and Go 1.14 becomes unsupported.
-	done["windows-arm"] = true  // TODO(golang.org/issue/38607) disabled until builder is replaced
 	done["darwin-arm64"] = true // TODO(golang.org/issue/39782): Add builder for darwin/arm64.
 	check := func(goos, goarch string) {
 		if goos == "android" || goos == "ios" {