2 files changed, 27 insertions, 0 deletions
diff --git a/src/syscall/syscall_windows.go b/src/syscall/syscall_windows.go
index c4782031a4..f7fca07301 100644
--- a/src/syscall/syscall_windows.go
+++ b/src/syscall/syscall_windows.go
@@ -138,12 +138,32 @@ func FormatMessage(flags uint32, msgsrc uint32, msgid uint32, langid uint32, buf
 	return formatMessage(flags, uintptr(msgsrc), msgid, langid, buf, args)
 }
 
+var errnoErrorCache sync.Map
+
 func (e Errno) Error() string {
 	// deal with special go errors
 	idx := int(e - APPLICATION_ERROR)
 	if 0 <= idx && idx < len(errors) {
 		return errors[idx]
 	}
+
+	cache := false
+	switch e {
+	case ERROR_FILE_NOT_FOUND, ERROR_PATH_NOT_FOUND:
+		if cached, ok := errnoErrorCache.Load(e); ok {
+			return cached.(string)
+		}
+		cache = true
+	}
+
+	result := e.error()
+	if cache {
+		errnoErrorCache.Store(e, result)
+	}
+	return result
+}
+
+func (e Errno) error() string {
 	// ask windows for the remaining errors
 	var flags uint32 = FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ARGUMENT_ARRAY | FORMAT_MESSAGE_IGNORE_INSERTS
 	b := make([]uint16, 300)
diff --git a/src/syscall/syscall_windows_test.go b/src/syscall/syscall_windows_test.go
index 882a279692..5e6ba9dbed 100644
--- a/src/syscall/syscall_windows_test.go
+++ b/src/syscall/syscall_windows_test.go
@@ -299,3 +299,10 @@ func FuzzUTF16FromString(f *testing.F) {
 		}
 	})
 }
+
+func BenchmarkErrnoString(b *testing.B) {
+	b.ReportAllocs()
+	for b.Loop() {
+		_ = syscall.Errno(2).Error()
+	}
+}