internal/sysinfo: use sync.OnceValue for CPUName

Change-Id: I0f3ae97f2bd5ff3f533c5bf4570a8cda8b92b16a
Reviewed-on: https://go-review.googlesource.com/c/go/+/582836
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Tobias Klauser <tobias.klauser@gmail.com>

src/internal/sysinfo/sysinfo.go

@@ -11,25 +11,14 @@ import (
 	"sync"
 )
 
-var cpuInfo struct {
+var CPUName = sync.OnceValue(func() string {
-	once sync.Once
+	if name := cpu.Name(); name != "" {
-	name string
+		return name
-}
+	}
 
-func CPUName() string {
+	if name := osCpuInfoName(); name != "" {
-	cpuInfo.once.Do(func() {
+		return name
-		// Try to get the information from internal/cpu.
+	}
-		if name := cpu.Name(); name != "" {
-			cpuInfo.name = name
-			return
-		}
 
-		// TODO(martisch): use /proc/cpuinfo and /sys/devices/system/cpu/ on Linux as fallback.
+	return ""
-		if name := osCpuInfoName(); name != "" {
+})
-			cpuInfo.name = name
-			return
-		}
-	})
-
-	return cpuInfo.name
-}