cmd/dist: support dist tool for loong64

Contributors to the loong64 port are:
  Weining Lu <luweining@loongson.cn>
  Lei Wang <wanglei@loongson.cn>
  Lingqin Gong <gonglingqin@loongson.cn>
  Xiaolin Zhao <zhaoxiaolin@loongson.cn>
  Meidan Li <limeidan@loongson.cn>
  Xiaojuan Zhai <zhaixiaojuan@loongson.cn>
  Qiyuan Pu <puqiyuan@loongson.cn>
  Guoqi Chen <chenguoqi@loongson.cn>

This port has been updated to Go 1.15.6:
  https://github.com/loongson/go

Updates #46229

Change-Id: I61dca43680d8e5bd3198a38577450a53f405a987
Reviewed-on: https://go-review.googlesource.com/c/go/+/342307


Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>

src/cmd/dist/build.go

@@ -64,6 +64,7 @@ var okgoarch = []string{
 	"amd64",
 	"arm",
 	"arm64",
+	"loong64",
 	"mips",
 	"mipsle",
 	"mips64",
@@ -1554,6 +1555,7 @@ var cgoEnabled = map[string]bool{
 	"linux/amd64":     true,
 	"linux/arm":       true,
 	"linux/arm64":     true,
+	"linux/loong64":   true,
 	"linux/ppc64":     false,
 	"linux/ppc64le":   true,
 	"linux/mips":      true,
@@ -1593,6 +1595,7 @@ var cgoEnabled = map[string]bool{
 // filtered out of cgoEnabled for 'dist list'. See golang.org/issue/28944
 var incomplete = map[string]bool{
 	"linux/sparc64": true,
+	"linux/loong64": true,
 }
 
 // List of platforms which are first class ports. See golang.org/issue/38874.

src/cmd/dist/buildtool.go

@@ -87,6 +87,8 @@ var ignorePrefixes = []string{
 var ignoreSuffixes = []string{
 	"_arm64.s",
 	"_arm64.go",
+	"_loong64.s",
+	"_loong64.go",
 	"_riscv64.s",
 	"_riscv64.go",
 	"_wasm.s",

src/cmd/dist/main.go

@@ -133,6 +133,8 @@ func main() {
 			if elfIsLittleEndian(os.Args[0]) {
 				gohostarch = "mipsle"
 			}
+		case strings.Contains(out, "loongarch64"):
+			gohostarch = "loong64"
 		case strings.Contains(out, "riscv64"):
 			gohostarch = "riscv64"
 		case strings.Contains(out, "s390x"):

src/cmd/dist/test.go

@@ -1035,7 +1035,7 @@ func (t *tester) extLink() bool {
 		"darwin-amd64", "darwin-arm64",
 		"dragonfly-amd64",
 		"freebsd-386", "freebsd-amd64", "freebsd-arm",
-		"linux-386", "linux-amd64", "linux-arm", "linux-arm64", "linux-ppc64le", "linux-mips64", "linux-mips64le", "linux-mips", "linux-mipsle", "linux-riscv64", "linux-s390x",
+		"linux-386", "linux-amd64", "linux-arm", "linux-arm64", "linux-loong64", "linux-ppc64le", "linux-mips64", "linux-mips64le", "linux-mips", "linux-mipsle", "linux-riscv64", "linux-s390x",
 		"netbsd-386", "netbsd-amd64",
 		"openbsd-386", "openbsd-amd64",
 		"windows-386", "windows-amd64":
@@ -1061,7 +1061,7 @@ func (t *tester) internalLink() bool {
 	// Internally linking cgo is incomplete on some architectures.
 	// https://golang.org/issue/10373
 	// https://golang.org/issue/14449
-	if goarch == "mips64" || goarch == "mips64le" || goarch == "mips" || goarch == "mipsle" || goarch == "riscv64" {
+	if goarch == "loong64" || goarch == "mips64" || goarch == "mips64le" || goarch == "mips" || goarch == "mipsle" || goarch == "riscv64" {
 		return false
 	}
 	if goos == "aix" {