libgo: update to Go1.12beta2

    
    Reviewed-on: https://go-review.googlesource.com/c/158019

gotools/:
	* Makefile.am (go_cmd_vet_files): Update for Go1.12beta2 release.
	(GOTOOLS_TEST_TIMEOUT): Increase to 600.
	(check-runtime): Export LD_LIBRARY_PATH before computing GOARCH
	and GOOS.
	(check-vet): Copy golang.org/x/tools into check-vet-dir.
	* Makefile.in: Regenerate.

gcc/testsuite/:
	* go.go-torture/execute/names-1.go: Stop using debug/xcoff, which
	is no longer externally visible.

From-SVN: r268084

1 files changed, 58 insertions, 4 deletions

diff --git a/libgo/go/net/lookup.go b/libgo/go/net/lookup.go
index e0f21fa9a8d..e10889331e4 100644
--- a/libgo/go/net/lookup.go
+++ b/libgo/go/net/lookup.go
@@ -97,6 +97,19 @@ func lookupPortMap(network, service string) (port int, error error) {
 	return 0, &AddrError{Err: "unknown port", Addr: network + "/" + service}
 }
 
+// ipVersion returns the provided network's IP version: '4', '6' or 0
+// if network does not end in a '4' or '6' byte.
+func ipVersion(network string) byte {
+	if network == "" {
+		return 0
+	}
+	n := network[len(network)-1]
+	if n != '4' && n != '6' {
+		n = 0
+	}
+	return n
+}
+
 // DefaultResolver is the resolver used by the package-level Lookup
 // functions and by Dialers without a specified Resolver.
 var DefaultResolver = &Resolver{}
@@ -189,6 +202,39 @@ func LookupIP(host string) ([]IP, error) {
 // LookupIPAddr looks up host using the local resolver.
 // It returns a slice of that host's IPv4 and IPv6 addresses.
 func (r *Resolver) LookupIPAddr(ctx context.Context, host string) ([]IPAddr, error) {
+	return r.lookupIPAddr(ctx, "ip", host)
+}
+
+// onlyValuesCtx is a context that uses an underlying context
+// for value lookup if the underlying context hasn't yet expired.
+type onlyValuesCtx struct {
+	context.Context
+	lookupValues context.Context
+}
+
+var _ context.Context = (*onlyValuesCtx)(nil)
+
+// Value performs a lookup if the original context hasn't expired.
+func (ovc *onlyValuesCtx) Value(key interface{}) interface{} {
+	select {
+	case <-ovc.lookupValues.Done():
+		return nil
+	default:
+		return ovc.lookupValues.Value(key)
+	}
+}
+
+// withUnexpiredValuesPreserved returns a context.Context that only uses lookupCtx
+// for its values, otherwise it is never canceled and has no deadline.
+// If the lookup context expires, any looked up values will return nil.
+// See Issue 28600.
+func withUnexpiredValuesPreserved(lookupCtx context.Context) context.Context {
+	return &onlyValuesCtx{Context: context.Background(), lookupValues: lookupCtx}
+}
+
+// lookupIPAddr looks up host using the local resolver and particular network.
+// It returns a slice of that host's IPv4 and IPv6 addresses.
+func (r *Resolver) lookupIPAddr(ctx context.Context, network, host string) ([]IPAddr, error) {
 	// Make sure that no matter what we do later, host=="" is rejected.
 	// parseIP, for example, does accept empty strings.
 	if host == "" {
@@ -205,20 +251,21 @@ func (r *Resolver) LookupIPAddr(ctx context.Context, host string) ([]IPAddr, err
 	// can be overridden by tests. This is needed by net/http, so it
 	// uses a context key instead of unexported variables.
 	resolverFunc := r.lookupIP
-	if alt, _ := ctx.Value(nettrace.LookupIPAltResolverKey{}).(func(context.Context, string) ([]IPAddr, error)); alt != nil {
+	if alt, _ := ctx.Value(nettrace.LookupIPAltResolverKey{}).(func(context.Context, string, string) ([]IPAddr, error)); alt != nil {
 		resolverFunc = alt
 	}
 
 	// We don't want a cancelation of ctx to affect the
 	// lookupGroup operation. Otherwise if our context gets
 	// canceled it might cause an error to be returned to a lookup
-	// using a completely different context.
-	lookupGroupCtx, lookupGroupCancel := context.WithCancel(context.Background())
+	// using a completely different context. However we need to preserve
+	// only the values in context. See Issue 28600.
+	lookupGroupCtx, lookupGroupCancel := context.WithCancel(withUnexpiredValuesPreserved(ctx))
 
 	dnsWaitGroup.Add(1)
 	ch, called := r.getLookupGroup().DoChan(host, func() (interface{}, error) {
 		defer dnsWaitGroup.Done()
-		return testHookLookupIP(lookupGroupCtx, resolverFunc, host)
+		return testHookLookupIP(lookupGroupCtx, resolverFunc, network, host)
 	})
 	if !called {
 		dnsWaitGroup.Done()
@@ -289,6 +336,13 @@ func LookupPort(network, service string) (port int, err error) {
 func (r *Resolver) LookupPort(ctx context.Context, network, service string) (port int, err error) {
 	port, needsLookup := parsePort(service)
 	if needsLookup {
+		switch network {
+		case "tcp", "tcp4", "tcp6", "udp", "udp4", "udp6":
+		case "": // a hint wildcard for Go 1.0 undocumented behavior
+			network = "ip"
+		default:
+			return 0, &AddrError{Err: "unknown network", Addr: network}
+		}
 		port, err = r.lookupPort(ctx, network, service)
 		if err != nil {
 			return 0, err