libgo: Update to current sources.

From-SVN: r192704

27 files changed, 1134 insertions, 278 deletions

diff --git a/libgo/go/encoding/asn1/asn1.go b/libgo/go/encoding/asn1/asn1.go
index ac2b5f8daa6..cac9d64b5e9 100644
--- a/libgo/go/encoding/asn1/asn1.go
+++ b/libgo/go/encoding/asn1/asn1.go
@@ -77,15 +77,15 @@ func parseInt64(bytes []byte) (ret int64, err error) {
 
 // parseInt treats the given bytes as a big-endian, signed integer and returns
 // the result.
-func parseInt(bytes []byte) (int, error) {
+func parseInt32(bytes []byte) (int32, error) {
 	ret64, err := parseInt64(bytes)
 	if err != nil {
 		return 0, err
 	}
-	if ret64 != int64(int(ret64)) {
+	if ret64 != int64(int32(ret64)) {
 		return 0, StructuralError{"integer too large"}
 	}
-	return int(ret64), nil
+	return int32(ret64), nil
 }
 
 var bigOne = big.NewInt(1)
@@ -670,7 +670,7 @@ func parseField(v reflect.Value, bytes []byte, initOffset int, params fieldParam
 		err = err1
 		return
 	case enumeratedType:
-		parsedInt, err1 := parseInt(innerBytes)
+		parsedInt, err1 := parseInt32(innerBytes)
 		if err1 == nil {
 			v.SetInt(int64(parsedInt))
 		}
@@ -692,19 +692,20 @@ func parseField(v reflect.Value, bytes []byte, initOffset int, params fieldParam
 		}
 		err = err1
 		return
-	case reflect.Int, reflect.Int32:
-		parsedInt, err1 := parseInt(innerBytes)
-		if err1 == nil {
-			val.SetInt(int64(parsedInt))
-		}
-		err = err1
-		return
-	case reflect.Int64:
-		parsedInt, err1 := parseInt64(innerBytes)
-		if err1 == nil {
-			val.SetInt(parsedInt)
+	case reflect.Int, reflect.Int32, reflect.Int64:
+		if val.Type().Size() == 4 {
+			parsedInt, err1 := parseInt32(innerBytes)
+			if err1 == nil {
+				val.SetInt(int64(parsedInt))
+			}
+			err = err1
+		} else {
+			parsedInt, err1 := parseInt64(innerBytes)
+			if err1 == nil {
+				val.SetInt(parsedInt)
+			}
+			err = err1
 		}
-		err = err1
 		return
 	// TODO(dfc) Add support for the remaining integer types
 	case reflect.Struct:
diff --git a/libgo/go/encoding/asn1/asn1_test.go b/libgo/go/encoding/asn1/asn1_test.go
index eb848bdb4af..cabdf03b482 100644
--- a/libgo/go/encoding/asn1/asn1_test.go
+++ b/libgo/go/encoding/asn1/asn1_test.go
@@ -64,7 +64,7 @@ var int32TestData = []int32Test{
 
 func TestParseInt32(t *testing.T) {
 	for i, test := range int32TestData {
-		ret, err := parseInt(test.in)
+		ret, err := parseInt32(test.in)
 		if (err == nil) != test.ok {
 			t.Errorf("#%d: Incorrect error result (did fail? %v, expected: %v)", i, err == nil, test.ok)
 		}
diff --git a/libgo/go/encoding/asn1/common.go b/libgo/go/encoding/asn1/common.go
index 03856bc55c5..33a117ece19 100644
--- a/libgo/go/encoding/asn1/common.go
+++ b/libgo/go/encoding/asn1/common.go
@@ -98,6 +98,8 @@ func parseFieldParameters(str string) (ret fieldParameters) {
 			ret.stringType = tagIA5String
 		case part == "printable":
 			ret.stringType = tagPrintableString
+		case part == "utf8":
+			ret.stringType = tagUTF8String
 		case strings.HasPrefix(part, "default:"):
 			i, err := strconv.ParseInt(part[8:], 10, 64)
 			if err == nil {
diff --git a/libgo/go/encoding/asn1/marshal.go b/libgo/go/encoding/asn1/marshal.go
index 163bca575de..3fd6be8ad92 100644
--- a/libgo/go/encoding/asn1/marshal.go
+++ b/libgo/go/encoding/asn1/marshal.go
@@ -6,11 +6,13 @@ package asn1
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
 	"math/big"
 	"reflect"
 	"time"
+	"unicode/utf8"
 )
 
 // A forkableWriter is an in-memory buffer that can be
@@ -280,6 +282,11 @@ func marshalIA5String(out *forkableWriter, s string) (err error) {
 	return
 }
 
+func marshalUTF8String(out *forkableWriter, s string) (err error) {
+	_, err = out.Write([]byte(s))
+	return
+}
+
 func marshalTwoDigits(out *forkableWriter, v int) (err error) {
 	err = out.WriteByte(byte('0' + (v/10)%10))
 	if err != nil {
@@ -446,10 +453,13 @@ func marshalBody(out *forkableWriter, value reflect.Value, params fieldParameter
 		}
 		return
 	case reflect.String:
-		if params.stringType == tagIA5String {
+		switch params.stringType {
+		case tagIA5String:
 			return marshalIA5String(out, v.String())
-		} else {
+		case tagPrintableString:
 			return marshalPrintableString(out, v.String())
+		default:
+			return marshalUTF8String(out, v.String())
 		}
 		return
 	}
@@ -492,11 +502,27 @@ func marshalField(out *forkableWriter, v reflect.Value, params fieldParameters)
 	}
 	class := classUniversal
 
-	if params.stringType != 0 {
-		if tag != tagPrintableString {
-			return StructuralError{"Explicit string type given to non-string member"}
+	if params.stringType != 0 && tag != tagPrintableString {
+		return StructuralError{"Explicit string type given to non-string member"}
+	}
+
+	if tag == tagPrintableString {
+		if params.stringType == 0 {
+			// This is a string without an explicit string type. We'll use
+			// a PrintableString if the character set in the string is
+			// sufficiently limited, otherwise we'll use a UTF8String.
+			for _, r := range v.String() {
+				if r >= utf8.RuneSelf || !isPrintable(byte(r)) {
+					if !utf8.ValidString(v.String()) {
+						return errors.New("asn1: string not valid UTF-8")
+					}
+					tag = tagUTF8String
+					break
+				}
+			}
+		} else {
+			tag = params.stringType
 		}
-		tag = params.stringType
 	}
 
 	if params.set {
diff --git a/libgo/go/encoding/asn1/marshal_test.go b/libgo/go/encoding/asn1/marshal_test.go
index f43bcae681a..c203533a917 100644
--- a/libgo/go/encoding/asn1/marshal_test.go
+++ b/libgo/go/encoding/asn1/marshal_test.go
@@ -122,6 +122,7 @@ var marshalTests = []marshalTest{
 	{testSET([]int{10}), "310302010a"},
 	{omitEmptyTest{[]string{}}, "3000"},
 	{omitEmptyTest{[]string{"1"}}, "30053003130131"},
+	{"Σ", "0c02cea3"},
 }
 
 func TestMarshal(t *testing.T) {
@@ -137,3 +138,10 @@ func TestMarshal(t *testing.T) {
 		}
 	}
 }
+
+func TestInvalidUTF8(t *testing.T) {
+	_, err := Marshal(string([]byte{0xff, 0xff}))
+	if err == nil {
+		t.Errorf("invalid UTF8 string was accepted")
+	}
+}
diff --git a/libgo/go/encoding/base32/base32.go b/libgo/go/encoding/base32/base32.go
index 71da6e22b12..dbefc48fa37 100644
--- a/libgo/go/encoding/base32/base32.go
+++ b/libgo/go/encoding/base32/base32.go
@@ -237,7 +237,6 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 		dlen := 8
 
 		// do the top bytes contain any data?
-	dbufloop:
 		for j := 0; j < 8; {
 			if len(src) == 0 {
 				return n, false, CorruptInputError(len(osrc) - len(src) - j)
@@ -258,7 +257,7 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 				}
 				dlen = j
 				end = true
-				break dbufloop
+				break
 			}
 			dbuf[j] = enc.decodeMap[in]
 			if dbuf[j] == 0xFF {
diff --git a/libgo/go/encoding/base64/base64.go b/libgo/go/encoding/base64/base64.go
index 0b842f06610..e66672a1c93 100644
--- a/libgo/go/encoding/base64/base64.go
+++ b/libgo/go/encoding/base64/base64.go
@@ -216,7 +216,6 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 		var dbuf [4]byte
 		dlen := 4
 
-	dbufloop:
 		for j := 0; j < 4; {
 			if len(src) == 0 {
 				return n, false, CorruptInputError(len(osrc) - len(src) - j)
@@ -240,7 +239,7 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 				}
 				dlen = j
 				end = true
-				break dbufloop
+				break
 			}
 			dbuf[j] = enc.decodeMap[in]
 			if dbuf[j] == 0xFF {
diff --git a/libgo/go/encoding/csv/writer.go b/libgo/go/encoding/csv/writer.go
index c4dcba5668a..324944cc829 100644
--- a/libgo/go/encoding/csv/writer.go
+++ b/libgo/go/encoding/csv/writer.go
@@ -101,11 +101,10 @@ func (w *Writer) WriteAll(records [][]string) (err error) {
 	for _, record := range records {
 		err = w.Write(record)
 		if err != nil {
-			break
+			return err
 		}
 	}
-	w.Flush()
-	return nil
+	return w.w.Flush()
 }
 
 // fieldNeedsQuotes returns true if our field must be enclosed in quotes.
diff --git a/libgo/go/encoding/gob/codec_test.go b/libgo/go/encoding/gob/codec_test.go
index ebcbb78ebe6..482212b7467 100644
--- a/libgo/go/encoding/gob/codec_test.go
+++ b/libgo/go/encoding/gob/codec_test.go
@@ -7,6 +7,7 @@ package gob
 import (
 	"bytes"
 	"errors"
+	"flag"
 	"math"
 	"math/rand"
 	"reflect"
@@ -16,6 +17,8 @@ import (
 	"unsafe"
 )
 
+var doFuzzTests = flag.Bool("gob.fuzz", false, "run the fuzz tests, which are large and very slow")
+
 // Guarantee encoding format by comparing some encodings to hand-written values
 type EncodeT struct {
 	x uint64
@@ -1434,7 +1437,8 @@ func encFuzzDec(rng *rand.Rand, in interface{}) error {
 
 // This does some "fuzz testing" by attempting to decode a sequence of random bytes.
 func TestFuzz(t *testing.T) {
-	if testing.Short() {
+	if !*doFuzzTests {
+		t.Logf("disabled; run with -gob.fuzz to enable")
 		return
 	}
 
@@ -1453,11 +1457,16 @@ func TestFuzz(t *testing.T) {
 }
 
 func TestFuzzRegressions(t *testing.T) {
+	if !*doFuzzTests {
+		t.Logf("disabled; run with -gob.fuzz to enable")
+		return
+	}
+
 	// An instance triggering a type name of length ~102 GB.
 	testFuzz(t, 1328492090837718000, 100, new(float32))
 	// An instance triggering a type name of 1.6 GB.
-	// Commented out because it takes 5m to run.
-	//testFuzz(t, 1330522872628565000, 100, new(int))
+	// Note: can take several minutes to run.
+	testFuzz(t, 1330522872628565000, 100, new(int))
 }
 
 func testFuzz(t *testing.T, seed int64, n int, input ...interface{}) {
diff --git a/libgo/go/encoding/gob/decode.go b/libgo/go/encoding/gob/decode.go
index 8690b35d714..900c69ddb47 100644
--- a/libgo/go/encoding/gob/decode.go
+++ b/libgo/go/encoding/gob/decode.go
@@ -717,7 +717,9 @@ func (dec *Decoder) decodeInterface(ityp reflect.Type, state *decoderState, p ui
 		errorf("name too long (%d bytes): %.20q...", len(name), name)
 	}
 	// The concrete type must be registered.
+	registerLock.RLock()
 	typ, ok := nameToConcreteType[name]
+	registerLock.RUnlock()
 	if !ok {
 		errorf("name not registered for interface: %q", name)
 	}
diff --git a/libgo/go/encoding/gob/decoder.go b/libgo/go/encoding/gob/decoder.go
index c5c7d3fdb10..04f706ca540 100644
--- a/libgo/go/encoding/gob/decoder.go
+++ b/libgo/go/encoding/gob/decoder.go
@@ -87,21 +87,38 @@ func (dec *Decoder) recvMessage() bool {
 
 // readMessage reads the next nbytes bytes from the input.
 func (dec *Decoder) readMessage(nbytes int) {
-	// Allocate the buffer.
-	if cap(dec.tmp) < nbytes {
-		dec.tmp = make([]byte, nbytes+100) // room to grow
+	// Allocate the dec.tmp buffer, up to 10KB.
+	const maxBuf = 10 * 1024
+	nTmp := nbytes
+	if nTmp > maxBuf {
+		nTmp = maxBuf
 	}
-	dec.tmp = dec.tmp[:nbytes]
+	if cap(dec.tmp) < nTmp {
+		nAlloc := nTmp + 100 // A little extra for growth.
+		if nAlloc > maxBuf {
+			nAlloc = maxBuf
+		}
+		dec.tmp = make([]byte, nAlloc)
+	}
+	dec.tmp = dec.tmp[:nTmp]
 
 	// Read the data
-	_, dec.err = io.ReadFull(dec.r, dec.tmp)
-	if dec.err != nil {
-		if dec.err == io.EOF {
-			dec.err = io.ErrUnexpectedEOF
+	dec.buf.Grow(nbytes)
+	for nbytes > 0 {
+		if nbytes < nTmp {
+			dec.tmp = dec.tmp[:nbytes]
 		}
-		return
+		var nRead int
+		nRead, dec.err = io.ReadFull(dec.r, dec.tmp)
+		if dec.err != nil {
+			if dec.err == io.EOF {
+				dec.err = io.ErrUnexpectedEOF
+			}
+			return
+		}
+		dec.buf.Write(dec.tmp)
+		nbytes -= nRead
 	}
-	dec.buf.Write(dec.tmp)
 }
 
 // toInt turns an encoded uint64 into an int, according to the marshaling rules.
diff --git a/libgo/go/encoding/gob/encode.go b/libgo/go/encoding/gob/encode.go
index 168e08b137a..ea37a6cbd58 100644
--- a/libgo/go/encoding/gob/encode.go
+++ b/libgo/go/encoding/gob/encode.go
@@ -426,6 +426,12 @@ func (enc *Encoder) encodeMap(b *bytes.Buffer, mv reflect.Value, keyOp, elemOp e
 // by the concrete value.  A nil value gets sent as the empty string for the name,
 // followed by no value.
 func (enc *Encoder) encodeInterface(b *bytes.Buffer, iv reflect.Value) {
+	// Gobs can encode nil interface values but not typed interface
+	// values holding nil pointers, since nil pointers point to no value.
+	elem := iv.Elem()
+	if elem.Kind() == reflect.Ptr && elem.IsNil() {
+		errorf("gob: cannot encode nil pointer of type %s inside interface", iv.Elem().Type())
+	}
 	state := enc.newEncoderState(b)
 	state.fieldnum = -1
 	state.sendZero = true
@@ -435,7 +441,9 @@ func (enc *Encoder) encodeInterface(b *bytes.Buffer, iv reflect.Value) {
 	}
 
 	ut := userType(iv.Elem().Type())
+	registerLock.RLock()
 	name, ok := concreteTypeToName[ut.base]
+	registerLock.RUnlock()
 	if !ok {
 		errorf("type not registered for interface: %s", ut.base)
 	}
@@ -454,7 +462,7 @@ func (enc *Encoder) encodeInterface(b *bytes.Buffer, iv reflect.Value) {
 	enc.pushWriter(b)
 	data := new(bytes.Buffer)
 	data.Write(spaceForLength)
-	enc.encode(data, iv.Elem(), ut)
+	enc.encode(data, elem, ut)
 	if enc.err != nil {
 		error_(enc.err)
 	}
@@ -698,9 +706,20 @@ func (enc *Encoder) getEncEngine(ut *userTypeInfo) *encEngine {
 		error_(err1)
 	}
 	if info.encoder == nil {
-		// mark this engine as underway before compiling to handle recursive types.
+		// Assign the encEngine now, so recursive types work correctly. But...
 		info.encoder = new(encEngine)
+		// ... if we fail to complete building the engine, don't cache the half-built machine.
+		// Doing this here means we won't cache a type that is itself OK but
+		// that contains a nested type that won't compile. The result is consistent
+		// error behavior when Encode is called multiple times on the top-level type.
+		ok := false
+		defer func() {
+			if !ok {
+				info.encoder = nil
+			}
+		}()
 		info.encoder = enc.compileEnc(ut)
+		ok = true
 	}
 	return info.encoder
 }
diff --git a/libgo/go/encoding/gob/encoder.go b/libgo/go/encoding/gob/encoder.go
index a15b5a1f9a1..51444bb5269 100644
--- a/libgo/go/encoding/gob/encoder.go
+++ b/libgo/go/encoding/gob/encoder.go
@@ -218,6 +218,12 @@ func (enc *Encoder) sendTypeId(state *encoderState, ut *userTypeInfo) {
 // EncodeValue transmits the data item represented by the reflection value,
 // guaranteeing that all necessary type information has been transmitted first.
 func (enc *Encoder) EncodeValue(value reflect.Value) error {
+	// Gobs contain values. They cannot represent nil pointers, which
+	// have no value to encode.
+	if value.Kind() == reflect.Ptr && value.IsNil() {
+		panic("gob: cannot encode nil pointer of type " + value.Type().String())
+	}
+
 	// Make sure we're single-threaded through here, so multiple
 	// goroutines can share an encoder.
 	enc.mutex.Lock()
diff --git a/libgo/go/encoding/gob/encoder_test.go b/libgo/go/encoding/gob/encoder_test.go
index db824d99917..b684772c691 100644
--- a/libgo/go/encoding/gob/encoder_test.go
+++ b/libgo/go/encoding/gob/encoder_test.go
@@ -737,6 +737,83 @@ func TestPtrToMapOfMap(t *testing.T) {
 	}
 }
 
+// A top-level nil pointer generates a panic with a helpful string-valued message.
+func TestTopLevelNilPointer(t *testing.T) {
+	errMsg := topLevelNilPanic(t)
+	if errMsg == "" {
+		t.Fatal("top-level nil pointer did not panic")
+	}
+	if !strings.Contains(errMsg, "nil pointer") {
+		t.Fatal("expected nil pointer error, got:", errMsg)
+	}
+}
+
+func topLevelNilPanic(t *testing.T) (panicErr string) {
+	defer func() {
+		e := recover()
+		if err, ok := e.(string); ok {
+			panicErr = err
+		}
+	}()
+	var ip *int
+	buf := new(bytes.Buffer)
+	if err := NewEncoder(buf).Encode(ip); err != nil {
+		t.Fatal("error in encode:", err)
+	}
+	return
+}
+
+func TestNilPointerInsideInterface(t *testing.T) {
+	var ip *int
+	si := struct {
+		I interface{}
+	}{
+		I: ip,
+	}
+	buf := new(bytes.Buffer)
+	err := NewEncoder(buf).Encode(si)
+	if err == nil {
+		t.Fatal("expected error, got none")
+	}
+	errMsg := err.Error()
+	if !strings.Contains(errMsg, "nil pointer") || !strings.Contains(errMsg, "interface") {
+		t.Fatal("expected error about nil pointer and interface, got:", errMsg)
+	}
+}
+
+type Bug4Public struct {
+	Name   string
+	Secret Bug4Secret
+}
+
+type Bug4Secret struct {
+	a int // error: no exported fields.
+}
+
+// Test that a failed compilation doesn't leave around an executable encoder.
+// Issue 3273.
+func TestMutipleEncodingsOfBadType(t *testing.T) {
+	x := Bug4Public{
+		Name:   "name",
+		Secret: Bug4Secret{1},
+	}
+	buf := new(bytes.Buffer)
+	enc := NewEncoder(buf)
+	err := enc.Encode(x)
+	if err == nil {
+		t.Fatal("first encoding: expected error")
+	}
+	buf.Reset()
+	enc = NewEncoder(buf)
+	err = enc.Encode(x)
+	if err == nil {
+		t.Fatal("second encoding: expected error")
+	}
+	if !strings.Contains(err.Error(), "no exported fields") {
+		t.Errorf("expected error about no exported fields; got %v", err)
+	}
+}
+
 // There was an error check comparing the length of the input with the
 // length of the slice being decoded. It was wrong because the next
 // thing in the input might be a type definition, which would lead to
diff --git a/libgo/go/encoding/gob/type.go b/libgo/go/encoding/gob/type.go
index a8ee2fa4a5a..ea0db4eac45 100644
--- a/libgo/go/encoding/gob/type.go
+++ b/libgo/go/encoding/gob/type.go
@@ -712,6 +712,7 @@ type GobDecoder interface {
 }
 
 var (
+	registerLock       sync.RWMutex
 	nameToConcreteType = make(map[string]reflect.Type)
 	concreteTypeToName = make(map[reflect.Type]string)
 )
@@ -723,6 +724,8 @@ func RegisterName(name string, value interface{}) {
 		// reserved for nil
 		panic("attempt to register empty name")
 	}
+	registerLock.Lock()
+	defer registerLock.Unlock()
 	ut := userType(reflect.TypeOf(value))
 	// Check for incompatible duplicates. The name must refer to the
 	// same user type, and vice versa.
diff --git a/libgo/go/encoding/gob/type_test.go b/libgo/go/encoding/gob/type_test.go
index 42bdb4cf7bb..e230d22d431 100644
--- a/libgo/go/encoding/gob/type_test.go
+++ b/libgo/go/encoding/gob/type_test.go
@@ -5,6 +5,7 @@
 package gob
 
 import (
+	"bytes"
 	"reflect"
 	"testing"
 )
@@ -159,3 +160,63 @@ func TestRegistration(t *testing.T) {
 	Register(new(T))
 	Register(new(T))
 }
+
+type N1 struct{}
+type N2 struct{}
+
+// See comment in type.go/Register.
+func TestRegistrationNaming(t *testing.T) {
+	testCases := []struct {
+		t    interface{}
+		name string
+	}{
+		{&N1{}, "*gob.N1"},
+		{N2{}, "encoding/gob.N2"},
+	}
+
+	for _, tc := range testCases {
+		Register(tc.t)
+
+		tct := reflect.TypeOf(tc.t)
+		registerLock.RLock()
+		ct := nameToConcreteType[tc.name]
+		registerLock.RUnlock()
+		if ct != tct {
+			t.Errorf("nameToConcreteType[%q] = %v, want %v", tc.name, ct, tct)
+		}
+		// concreteTypeToName is keyed off the base type.
+		if tct.Kind() == reflect.Ptr {
+			tct = tct.Elem()
+		}
+		if n := concreteTypeToName[tct]; n != tc.name {
+			t.Errorf("concreteTypeToName[%v] got %v, want %v", tct, n, tc.name)
+		}
+	}
+}
+
+func TestStressParallel(t *testing.T) {
+	type T2 struct{ A int }
+	c := make(chan bool)
+	const N = 10
+	for i := 0; i < N; i++ {
+		go func() {
+			p := new(T2)
+			Register(p)
+			b := new(bytes.Buffer)
+			enc := NewEncoder(b)
+			err := enc.Encode(p)
+			if err != nil {
+				t.Error("encoder fail:", err)
+			}
+			dec := NewDecoder(b)
+			err = dec.Decode(p)
+			if err != nil {
+				t.Error("decoder fail:", err)
+			}
+			c <- true
+		}()
+	}
+	for i := 0; i < N; i++ {
+		<-c
+	}
+}
diff --git a/libgo/go/encoding/json/decode.go b/libgo/go/encoding/json/decode.go
index d61f8870646..47e3d89aa35 100644
--- a/libgo/go/encoding/json/decode.go
+++ b/libgo/go/encoding/json/decode.go
@@ -137,6 +137,22 @@ func (d *decodeState) unmarshal(v interface{}) (err error) {
 	return d.savedError
 }
 
+// A Number represents a JSON number literal.
+type Number string
+
+// String returns the literal text of the number.
+func (n Number) String() string { return string(n) }
+
+// Float64 returns the number as a float64.
+func (n Number) Float64() (float64, error) {
+	return strconv.ParseFloat(string(n), 64)
+}
+
+// Int64 returns the number as an int64.
+func (n Number) Int64() (int64, error) {
+	return strconv.ParseInt(string(n), 10, 64)
+}
+
 // decodeState represents the state while decoding a JSON value.
 type decodeState struct {
 	data       []byte
@@ -145,6 +161,7 @@ type decodeState struct {
 	nextscan   scanner // for calls to nextValue
 	savedError error
 	tempstr    string // scratch space to avoid some allocations
+	useNumber  bool
 }
 
 // errPhase is used for errors that should not happen unless
@@ -265,47 +282,32 @@ func (d *decodeState) indirect(v reflect.Value, decodingNull bool) (Unmarshaler,
 		v = v.Addr()
 	}
 	for {
-		var isUnmarshaler bool
-		if v.Type().NumMethod() > 0 {
-			// Remember that this is an unmarshaler,
-			// but wait to return it until after allocating
-			// the pointer (if necessary).
-			_, isUnmarshaler = v.Interface().(Unmarshaler)
-		}
-
 		// Load value from interface, but only if the result will be
 		// usefully addressable.
-		if iv := v; iv.Kind() == reflect.Interface && !iv.IsNil() {
-			e := iv.Elem()
+		if v.Kind() == reflect.Interface && !v.IsNil() {
+			e := v.Elem()
 			if e.Kind() == reflect.Ptr && !e.IsNil() && (!decodingNull || e.Elem().Kind() == reflect.Ptr) {
 				v = e
 				continue
 			}
 		}
 
-		pv := v
-		if pv.Kind() != reflect.Ptr {
+		if v.Kind() != reflect.Ptr {
 			break
 		}
 
-		if pv.Elem().Kind() != reflect.Ptr && decodingNull && pv.CanSet() {
-			return nil, pv
+		if v.Elem().Kind() != reflect.Ptr && decodingNull && v.CanSet() {
+			break
 		}
-		if pv.IsNil() {
-			pv.Set(reflect.New(pv.Type().Elem()))
+		if v.IsNil() {
+			v.Set(reflect.New(v.Type().Elem()))
 		}
-		if isUnmarshaler {
-			// Using v.Interface().(Unmarshaler)
-			// here means that we have to use a pointer
-			// as the struct field.  We cannot use a value inside
-			// a pointer to a struct, because in that case
-			// v.Interface() is the value (x.f) not the pointer (&x.f).
-			// This is an unfortunate consequence of reflect.
-			// An alternative would be to look up the
-			// UnmarshalJSON method and return a FuncValue.
-			return v.Interface().(Unmarshaler), reflect.Value{}
+		if v.Type().NumMethod() > 0 {
+			if unmarshaler, ok := v.Interface().(Unmarshaler); ok {
+				return unmarshaler, reflect.Value{}
+			}
 		}
-		v = pv.Elem()
+		v = v.Elem()
 	}
 	return nil, v
 }
@@ -491,51 +493,39 @@ func (d *decodeState) object(v reflect.Value) {
 			}
 			subv = mapElem
 		} else {
-			var f reflect.StructField
-			var ok bool
-			st := sv.Type()
-			for i := 0; i < sv.NumField(); i++ {
-				sf := st.Field(i)
-				tag := sf.Tag.Get("json")
-				if tag == "-" {
-					// Pretend this field doesn't exist.
-					continue
+			var f *field
+			fields := cachedTypeFields(sv.Type())
+			for i := range fields {
+				ff := &fields[i]
+				if ff.name == key {
+					f = ff
+					break
 				}
-				if sf.Anonymous {
-					// Pretend this field doesn't exist,
-					// so that we can do a good job with
-					// these in a later version.
-					continue
-				}
-				// First, tag match
-				tagName, _ := parseTag(tag)
-				if tagName == key {
-					f = sf
-					ok = true
-					break // no better match possible
-				}
-				// Second, exact field name match
-				if sf.Name == key {
-					f = sf
-					ok = true
-				}
-				// Third, case-insensitive field name match,
-				// but only if a better match hasn't already been seen
-				if !ok && strings.EqualFold(sf.Name, key) {
-					f = sf
-					ok = true
+				if f == nil && strings.EqualFold(ff.name, key) {
+					f = ff
 				}
 			}
-
-			// Extract value; name must be exported.
-			if ok {
-				if f.PkgPath != "" {
-					d.saveError(&UnmarshalFieldError{key, st, f})
-				} else {
-					subv = sv.FieldByIndex(f.Index)
+			if f != nil {
+				subv = sv
+				destring = f.quoted
+				for _, i := range f.index {
+					if subv.Kind() == reflect.Ptr {
+						if subv.IsNil() {
+							subv.Set(reflect.New(subv.Type().Elem()))
+						}
+						subv = subv.Elem()
+					}
+					subv = subv.Field(i)
+				}
+			} else {
+				// To give a good error, a quick scan for unexported fields in top level.
+				st := sv.Type()
+				for i := 0; i < st.NumField(); i++ {
+					f := st.Field(i)
+					if f.PkgPath != "" && strings.EqualFold(f.Name, key) {
+						d.saveError(&UnmarshalFieldError{key, st, f})
+					}
 				}
-				_, opts := parseTag(f.Tag.Get("json"))
-				destring = opts.Contains("string")
 			}
 		}
 
@@ -586,6 +576,21 @@ func (d *decodeState) literal(v reflect.Value) {
 	d.literalStore(d.data[start:d.off], v, false)
 }
 
+// convertNumber converts the number literal s to a float64 or a Number
+// depending on the setting of d.useNumber.
+func (d *decodeState) convertNumber(s string) (interface{}, error) {
+	if d.useNumber {
+		return Number(s), nil
+	}
+	f, err := strconv.ParseFloat(s, 64)
+	if err != nil {
+		return nil, &UnmarshalTypeError{"number " + s, reflect.TypeOf(0.0)}
+	}
+	return f, nil
+}
+
+var numberType = reflect.TypeOf(Number(""))
+
 // literalStore decodes a literal stored in item into v.
 //
 // fromQuoted indicates whether this literal came from unwrapping a
@@ -674,15 +679,19 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		s := string(item)
 		switch v.Kind() {
 		default:
+			if v.Kind() == reflect.String && v.Type() == numberType {
+				v.SetString(s)
+				break
+			}
 			if fromQuoted {
 				d.error(fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type()))
 			} else {
 				d.error(&UnmarshalTypeError{"number", v.Type()})
 			}
 		case reflect.Interface:
-			n, err := strconv.ParseFloat(s, 64)
+			n, err := d.convertNumber(s)
 			if err != nil {
-				d.saveError(&UnmarshalTypeError{"number " + s, v.Type()})
+				d.saveError(err)
 				break
 			}
 			v.Set(reflect.ValueOf(n))
@@ -836,9 +845,9 @@ func (d *decodeState) literalInterface() interface{} {
 		if c != '-' && (c < '0' || c > '9') {
 			d.error(errPhase)
 		}
-		n, err := strconv.ParseFloat(string(item), 64)
+		n, err := d.convertNumber(string(item))
 		if err != nil {
-			d.saveError(&UnmarshalTypeError{"number " + string(item), reflect.TypeOf(0.0)})
+			d.saveError(err)
 		}
 		return n
 	}
@@ -979,11 +988,3 @@ func unquoteBytes(s []byte) (t []byte, ok bool) {
 	}
 	return b[0:w], true
 }
-
-// The following is issue 3069.
-
-// BUG(rsc): This package ignores anonymous (embedded) struct fields
-// during encoding and decoding.  A future version may assign meaning
-// to them.  To force an anonymous field to be ignored in all future
-// versions of this package, use an explicit `json:"-"` tag in the struct
-// definition.
diff --git a/libgo/go/encoding/json/decode_test.go b/libgo/go/encoding/json/decode_test.go
index 6fac22c4a35..f2da141b8f9 100644
--- a/libgo/go/encoding/json/decode_test.go
+++ b/libgo/go/encoding/json/decode_test.go
@@ -7,6 +7,7 @@ package json
 import (
 	"bytes"
 	"fmt"
+	"image"
 	"reflect"
 	"strings"
 	"testing"
@@ -18,6 +19,32 @@ type T struct {
 	Z int `json:"-"`
 }
 
+type U struct {
+	Alphabet string `json:"alpha"`
+}
+
+type V struct {
+	F1 interface{}
+	F2 int32
+	F3 Number
+}
+
+// ifaceNumAsFloat64/ifaceNumAsNumber are used to test unmarshalling with and
+// without UseNumber
+var ifaceNumAsFloat64 = map[string]interface{}{
+	"k1": float64(1),
+	"k2": "s",
+	"k3": []interface{}{float64(1), float64(2.0), float64(3e-3)},
+	"k4": map[string]interface{}{"kk1": "s", "kk2": float64(2)},
+}
+
+var ifaceNumAsNumber = map[string]interface{}{
+	"k1": Number("1"),
+	"k2": "s",
+	"k3": []interface{}{Number("1"), Number("2.0"), Number("3e-3")},
+	"k4": map[string]interface{}{"kk1": "s", "kk2": Number("2")},
+}
+
 type tx struct {
 	x int
 }
@@ -48,55 +75,237 @@ var (
 	umstruct = ustruct{unmarshaler{true}}
 )
 
+// Test data structures for anonymous fields.
+
+type Point struct {
+	Z int
+}
+
+type Top struct {
+	Level0 int
+	Embed0
+	*Embed0a
+	*Embed0b `json:"e,omitempty"` // treated as named
+	Embed0c  `json:"-"`           // ignored
+	Loop
+	Embed0p // has Point with X, Y, used
+	Embed0q // has Point with Z, used
+}
+
+type Embed0 struct {
+	Level1a int // overridden by Embed0a's Level1a with json tag
+	Level1b int // used because Embed0a's Level1b is renamed
+	Level1c int // used because Embed0a's Level1c is ignored
+	Level1d int // annihilated by Embed0a's Level1d
+	Level1e int `json:"x"` // annihilated by Embed0a.Level1e
+}
+
+type Embed0a struct {
+	Level1a int `json:"Level1a,omitempty"`
+	Level1b int `json:"LEVEL1B,omitempty"`
+	Level1c int `json:"-"`
+	Level1d int // annihilated by Embed0's Level1d
+	Level1f int `json:"x"` // annihilated by Embed0's Level1e
+}
+
+type Embed0b Embed0
+
+type Embed0c Embed0
+
+type Embed0p struct {
+	image.Point
+}
+
+type Embed0q struct {
+	Point
+}
+
+type Loop struct {
+	Loop1 int `json:",omitempty"`
+	Loop2 int `json:",omitempty"`
+	*Loop
+}
+
+// From reflect test:
+// The X in S6 and S7 annihilate, but they also block the X in S8.S9.
+type S5 struct {
+	S6
+	S7
+	S8
+}
+
+type S6 struct {
+	X int
+}
+
+type S7 S6
+
+type S8 struct {
+	S9
+}
+
+type S9 struct {
+	X int
+	Y int
+}
+
+// From reflect test:
+// The X in S11.S6 and S12.S6 annihilate, but they also block the X in S13.S8.S9.
+type S10 struct {
+	S11
+	S12
+	S13
+}
+
+type S11 struct {
+	S6
+}
+
+type S12 struct {
+	S6
+}
+
+type S13 struct {
+	S8
+}
+
 type unmarshalTest struct {
-	in  string
-	ptr interface{}
-	out interface{}
-	err error
+	in        string
+	ptr       interface{}
+	out       interface{}
+	err       error
+	useNumber bool
+}
+
+type Ambig struct {
+	// Given "hello", the first match should win.
+	First  int `json:"HELLO"`
+	Second int `json:"Hello"`
 }
 
 var unmarshalTests = []unmarshalTest{
 	// basic types
-	{`true`, new(bool), true, nil},
-	{`1`, new(int), 1, nil},
-	{`1.2`, new(float64), 1.2, nil},
-	{`-5`, new(int16), int16(-5), nil},
-	{`"a\u1234"`, new(string), "a\u1234", nil},
-	{`"http:\/\/"`, new(string), "http://", nil},
-	{`"g-clef: \uD834\uDD1E"`, new(string), "g-clef: \U0001D11E", nil},
-	{`"invalid: \uD834x\uDD1E"`, new(string), "invalid: \uFFFDx\uFFFD", nil},
-	{"null", new(interface{}), nil, nil},
-	{`{"X": [1,2,3], "Y": 4}`, new(T), T{Y: 4}, &UnmarshalTypeError{"array", reflect.TypeOf("")}},
-	{`{"x": 1}`, new(tx), tx{}, &UnmarshalFieldError{"x", txType, txType.Field(0)}},
+	{in: `true`, ptr: new(bool), out: true},
+	{in: `1`, ptr: new(int), out: 1},
+	{in: `1.2`, ptr: new(float64), out: 1.2},
+	{in: `-5`, ptr: new(int16), out: int16(-5)},
+	{in: `2`, ptr: new(Number), out: Number("2"), useNumber: true},
+	{in: `2`, ptr: new(Number), out: Number("2")},
+	{in: `2`, ptr: new(interface{}), out: float64(2.0)},
+	{in: `2`, ptr: new(interface{}), out: Number("2"), useNumber: true},
+	{in: `"a\u1234"`, ptr: new(string), out: "a\u1234"},
+	{in: `"http:\/\/"`, ptr: new(string), out: "http://"},
+	{in: `"g-clef: \uD834\uDD1E"`, ptr: new(string), out: "g-clef: \U0001D11E"},
+	{in: `"invalid: \uD834x\uDD1E"`, ptr: new(string), out: "invalid: \uFFFDx\uFFFD"},
+	{in: "null", ptr: new(interface{}), out: nil},
+	{in: `{"X": [1,2,3], "Y": 4}`, ptr: new(T), out: T{Y: 4}, err: &UnmarshalTypeError{"array", reflect.TypeOf("")}},
+	{in: `{"x": 1}`, ptr: new(tx), out: tx{}, err: &UnmarshalFieldError{"x", txType, txType.Field(0)}},
+	{in: `{"F1":1,"F2":2,"F3":3}`, ptr: new(V), out: V{F1: float64(1), F2: int32(2), F3: Number("3")}},
+	{in: `{"F1":1,"F2":2,"F3":3}`, ptr: new(V), out: V{F1: Number("1"), F2: int32(2), F3: Number("3")}, useNumber: true},
+	{in: `{"k1":1,"k2":"s","k3":[1,2.0,3e-3],"k4":{"kk1":"s","kk2":2}}`, ptr: new(interface{}), out: ifaceNumAsFloat64},
+	{in: `{"k1":1,"k2":"s","k3":[1,2.0,3e-3],"k4":{"kk1":"s","kk2":2}}`, ptr: new(interface{}), out: ifaceNumAsNumber, useNumber: true},
 
 	// Z has a "-" tag.
-	{`{"Y": 1, "Z": 2}`, new(T), T{Y: 1}, nil},
+	{in: `{"Y": 1, "Z": 2}`, ptr: new(T), out: T{Y: 1}},
+
+	{in: `{"alpha": "abc", "alphabet": "xyz"}`, ptr: new(U), out: U{Alphabet: "abc"}},
+	{in: `{"alpha": "abc"}`, ptr: new(U), out: U{Alphabet: "abc"}},
+	{in: `{"alphabet": "xyz"}`, ptr: new(U), out: U{}},
 
 	// syntax errors
-	{`{"X": "foo", "Y"}`, nil, nil, &SyntaxError{"invalid character '}' after object key", 17}},
-	{`[1, 2, 3+]`, nil, nil, &SyntaxError{"invalid character '+' after array element", 9}},
+	{in: `{"X": "foo", "Y"}`, err: &SyntaxError{"invalid character '}' after object key", 17}},
+	{in: `[1, 2, 3+]`, err: &SyntaxError{"invalid character '+' after array element", 9}},
+	{in: `{"X":12x}`, err: &SyntaxError{"invalid character 'x' after object key:value pair", 8}, useNumber: true},
 
 	// array tests
-	{`[1, 2, 3]`, new([3]int), [3]int{1, 2, 3}, nil},
-	{`[1, 2, 3]`, new([1]int), [1]int{1}, nil},
-	{`[1, 2, 3]`, new([5]int), [5]int{1, 2, 3, 0, 0}, nil},
+	{in: `[1, 2, 3]`, ptr: new([3]int), out: [3]int{1, 2, 3}},
+	{in: `[1, 2, 3]`, ptr: new([1]int), out: [1]int{1}},
+	{in: `[1, 2, 3]`, ptr: new([5]int), out: [5]int{1, 2, 3, 0, 0}},
 
 	// composite tests
-	{allValueIndent, new(All), allValue, nil},
-	{allValueCompact, new(All), allValue, nil},
-	{allValueIndent, new(*All), &allValue, nil},
-	{allValueCompact, new(*All), &allValue, nil},
-	{pallValueIndent, new(All), pallValue, nil},
-	{pallValueCompact, new(All), pallValue, nil},
-	{pallValueIndent, new(*All), &pallValue, nil},
-	{pallValueCompact, new(*All), &pallValue, nil},
+	{in: allValueIndent, ptr: new(All), out: allValue},
+	{in: allValueCompact, ptr: new(All), out: allValue},
+	{in: allValueIndent, ptr: new(*All), out: &allValue},
+	{in: allValueCompact, ptr: new(*All), out: &allValue},
+	{in: pallValueIndent, ptr: new(All), out: pallValue},
+	{in: pallValueCompact, ptr: new(All), out: pallValue},
+	{in: pallValueIndent, ptr: new(*All), out: &pallValue},
+	{in: pallValueCompact, ptr: new(*All), out: &pallValue},
 
 	// unmarshal interface test
-	{`{"T":false}`, &um0, umtrue, nil}, // use "false" so test will fail if custom unmarshaler is not called
-	{`{"T":false}`, &ump, &umtrue, nil},
-	{`[{"T":false}]`, &umslice, umslice, nil},
-	{`[{"T":false}]`, &umslicep, &umslice, nil},
-	{`{"M":{"T":false}}`, &umstruct, umstruct, nil},
+	{in: `{"T":false}`, ptr: &um0, out: umtrue}, // use "false" so test will fail if custom unmarshaler is not called
+	{in: `{"T":false}`, ptr: &ump, out: &umtrue},
+	{in: `[{"T":false}]`, ptr: &umslice, out: umslice},
+	{in: `[{"T":false}]`, ptr: &umslicep, out: &umslice},
+	{in: `{"M":{"T":false}}`, ptr: &umstruct, out: umstruct},
+
+	{
+		in: `{
+			"Level0": 1,
+			"Level1b": 2,
+			"Level1c": 3,
+			"x": 4,
+			"Level1a": 5,
+			"LEVEL1B": 6,
+			"e": {
+				"Level1a": 8,
+				"Level1b": 9,
+				"Level1c": 10,
+				"Level1d": 11,
+				"x": 12
+			},
+			"Loop1": 13,
+			"Loop2": 14,
+			"X": 15,
+			"Y": 16,
+			"Z": 17
+		}`,
+		ptr: new(Top),
+		out: Top{
+			Level0: 1,
+			Embed0: Embed0{
+				Level1b: 2,
+				Level1c: 3,
+			},
+			Embed0a: &Embed0a{
+				Level1a: 5,
+				Level1b: 6,
+			},
+			Embed0b: &Embed0b{
+				Level1a: 8,
+				Level1b: 9,
+				Level1c: 10,
+				Level1d: 11,
+				Level1e: 12,
+			},
+			Loop: Loop{
+				Loop1: 13,
+				Loop2: 14,
+			},
+			Embed0p: Embed0p{
+				Point: image.Point{X: 15, Y: 16},
+			},
+			Embed0q: Embed0q{
+				Point: Point{Z: 17},
+			},
+		},
+	},
+	{
+		in:  `{"hello": 1}`,
+		ptr: new(Ambig),
+		out: Ambig{First: 1},
+	},
+
+	{
+		in:  `{"X": 1,"Y":2}`,
+		ptr: new(S5),
+		out: S5{S8: S8{S9: S9{Y: 2}}},
+	},
+	{
+		in:  `{"X": 1,"Y":2}`,
+		ptr: new(S10),
+		out: S10{S13: S13{S8: S8{S9: S9{Y: 2}}}},
+	},
 }
 
 func TestMarshal(t *testing.T) {
@@ -135,6 +344,18 @@ func TestMarshalBadUTF8(t *testing.T) {
 	}
 }
 
+func TestMarshalNumberZeroVal(t *testing.T) {
+	var n Number
+	out, err := Marshal(n)
+	if err != nil {
+		t.Fatal(err)
+	}
+	outStr := string(out)
+	if outStr != "0" {
+		t.Fatalf("Invalid zero val for Number: %q", outStr)
+	}
+}
+
 func TestUnmarshal(t *testing.T) {
 	for i, tt := range unmarshalTests {
 		var scan scanner
@@ -150,7 +371,11 @@ func TestUnmarshal(t *testing.T) {
 		}
 		// v = new(right-type)
 		v := reflect.New(reflect.TypeOf(tt.ptr).Elem())
-		if err := Unmarshal([]byte(in), v.Interface()); !reflect.DeepEqual(err, tt.err) {
+		dec := NewDecoder(bytes.NewBuffer(in))
+		if tt.useNumber {
+			dec.UseNumber()
+		}
+		if err := dec.Decode(v.Interface()); !reflect.DeepEqual(err, tt.err) {
 			t.Errorf("#%d: %v want %v", i, err, tt.err)
 			continue
 		}
@@ -162,6 +387,28 @@ func TestUnmarshal(t *testing.T) {
 			println(string(data))
 			continue
 		}
+
+		// Check round trip.
+		if tt.err == nil {
+			enc, err := Marshal(v.Interface())
+			if err != nil {
+				t.Errorf("#%d: error re-marshaling: %v", i, err)
+				continue
+			}
+			vv := reflect.New(reflect.TypeOf(tt.ptr).Elem())
+			dec = NewDecoder(bytes.NewBuffer(enc))
+			if tt.useNumber {
+				dec.UseNumber()
+			}
+			if err := dec.Decode(vv.Interface()); err != nil {
+				t.Errorf("#%d: error re-unmarshaling: %v", i, err)
+				continue
+			}
+			if !reflect.DeepEqual(v.Elem().Interface(), vv.Elem().Interface()) {
+				t.Errorf("#%d: mismatch\nhave: %#+v\nwant: %#+v", i, v.Elem().Interface(), vv.Elem().Interface())
+				continue
+			}
+		}
 	}
 }
 
@@ -182,6 +429,38 @@ func TestUnmarshalMarshal(t *testing.T) {
 	}
 }
 
+var numberTests = []struct {
+	in       string
+	i        int64
+	intErr   string
+	f        float64
+	floatErr string
+}{
+	{in: "-1.23e1", intErr: "strconv.ParseInt: parsing \"-1.23e1\": invalid syntax", f: -1.23e1},
+	{in: "-12", i: -12, f: -12.0},
+	{in: "1e1000", intErr: "strconv.ParseInt: parsing \"1e1000\": invalid syntax", floatErr: "strconv.ParseFloat: parsing \"1e1000\": value out of range"},
+}
+
+// Independent of Decode, basic coverage of the accessors in Number
+func TestNumberAccessors(t *testing.T) {
+	for _, tt := range numberTests {
+		n := Number(tt.in)
+		if s := n.String(); s != tt.in {
+			t.Errorf("Number(%q).String() is %q", tt.in, s)
+		}
+		if i, err := n.Int64(); err == nil && tt.intErr == "" && i != tt.i {
+			t.Errorf("Number(%q).Int64() is %d", tt.in, i)
+		} else if (err == nil && tt.intErr != "") || (err != nil && err.Error() != tt.intErr) {
+			t.Errorf("Number(%q).Int64() wanted error %q but got: %v", tt.in, tt.intErr, err)
+		}
+		if f, err := n.Float64(); err == nil && tt.floatErr == "" && f != tt.f {
+			t.Errorf("Number(%q).Float64() is %g", tt.in, f)
+		} else if (err == nil && tt.floatErr != "") || (err != nil && err.Error() != tt.floatErr) {
+			t.Errorf("Number(%q).Float64() wanted error %q but got: %v", tt.in, tt.floatErr, err)
+		}
+	}
+}
+
 func TestLargeByteSlice(t *testing.T) {
 	s0 := make([]byte, 2000)
 	for i := range s0 {
@@ -610,35 +889,6 @@ func TestRefUnmarshal(t *testing.T) {
 	}
 }
 
-// Test that anonymous fields are ignored.
-// We may assign meaning to them later.
-func TestAnonymous(t *testing.T) {
-	type S struct {
-		T
-		N int
-	}
-
-	data, err := Marshal(new(S))
-	if err != nil {
-		t.Fatalf("Marshal: %v", err)
-	}
-	want := `{"N":0}`
-	if string(data) != want {
-		t.Fatalf("Marshal = %#q, want %#q", string(data), want)
-	}
-
-	var s S
-	if err := Unmarshal([]byte(`{"T": 1, "T": {"Y": 1}, "N": 2}`), &s); err != nil {
-		t.Fatalf("Unmarshal: %v", err)
-	}
-	if s.N != 2 {
-		t.Fatal("Unmarshal: did not set N")
-	}
-	if s.T.Y != 0 {
-		t.Fatal("Unmarshal: did set T.Y")
-	}
-}
-
 // Test that the empty string doesn't panic decoding when ,string is specified
 // Issue 3450
 func TestEmptyString(t *testing.T) {
diff --git a/libgo/go/encoding/json/encode.go b/libgo/go/encoding/json/encode.go
index d2c1c4424c7..c8535ef79d6 100644
--- a/libgo/go/encoding/json/encode.go
+++ b/libgo/go/encoding/json/encode.go
@@ -36,7 +36,7 @@ import (
 //
 // Boolean values encode as JSON booleans.
 //
-// Floating point and integer values encode as JSON numbers.
+// Floating point, integer, and Number values encode as JSON numbers.
 //
 // String values encode as JSON strings, with each invalid UTF-8 sequence
 // replaced by the encoding of the Unicode replacement character U+FFFD.
@@ -84,6 +84,16 @@ import (
 // only Unicode letters, digits, dollar signs, percent signs, hyphens,
 // underscores and slashes.
 //
+// Anonymous struct fields are usually marshaled as if their inner exported fields
+// were fields in the outer struct, subject to the usual Go visibility rules.
+// An anonymous struct field with a name given in its JSON tag is treated as 
+// having that name instead of as anonymous.
+//
+// Handling of anonymous struct fields is new in Go 1.1.
+// Prior to Go 1.1, anonymous struct fields were ignored. To force ignoring of
+// an anonymous struct field in both current and earlier versions, give the field
+// a JSON tag of "-".
+//
 // Map values encode as JSON objects.
 // The map's key type must be string; the object keys are used directly
 // as map keys.
@@ -312,6 +322,14 @@ func (e *encodeState) reflectValueQuoted(v reflect.Value, quoted bool) {
 			e.Write(b)
 		}
 	case reflect.String:
+		if v.Type() == numberType {
+			numStr := v.String()
+			if numStr == "" {
+				numStr = "0" // Number's zero-val
+			}
+			e.WriteString(numStr)
+			break
+		}
 		if quoted {
 			sb, err := Marshal(v.String())
 			if err != nil {
@@ -325,9 +343,9 @@ func (e *encodeState) reflectValueQuoted(v reflect.Value, quoted bool) {
 	case reflect.Struct:
 		e.WriteByte('{')
 		first := true
-		for _, ef := range encodeFields(v.Type()) {
-			fieldValue := v.Field(ef.i)
-			if ef.omitEmpty && isEmptyValue(fieldValue) {
+		for _, f := range cachedTypeFields(v.Type()) {
+			fv := fieldByIndex(v, f.index)
+			if !fv.IsValid() || f.omitEmpty && isEmptyValue(fv) {
 				continue
 			}
 			if first {
@@ -335,9 +353,9 @@ func (e *encodeState) reflectValueQuoted(v reflect.Value, quoted bool) {
 			} else {
 				e.WriteByte(',')
 			}
-			e.string(ef.tag)
+			e.string(f.name)
 			e.WriteByte(':')
-			e.reflectValueQuoted(fieldValue, ef.quoted)
+			e.reflectValueQuoted(fv, f.quoted)
 		}
 		e.WriteByte('}')
 
@@ -432,6 +450,19 @@ func isValidTag(s string) bool {
 	return true
 }
 
+func fieldByIndex(v reflect.Value, index []int) reflect.Value {
+	for _, i := range index {
+		if v.Kind() == reflect.Ptr {
+			if v.IsNil() {
+				return reflect.Value{}
+			}
+			v = v.Elem()
+		}
+		v = v.Field(i)
+	}
+	return v
+}
+
 // stringValues is a slice of reflect.Value holding *reflect.StringValue.
 // It implements the methods to sort by string.
 type stringValues []reflect.Value
@@ -490,67 +521,183 @@ func (e *encodeState) string(s string) (int, error) {
 	return e.Len() - len0, nil
 }
 
-// encodeField contains information about how to encode a field of a
-// struct.
-type encodeField struct {
-	i         int // field index in struct
-	tag       string
-	quoted    bool
+// A field represents a single field found in a struct.
+type field struct {
+	name      string
+	tag       bool
+	index     []int
+	typ       reflect.Type
 	omitEmpty bool
+	quoted    bool
 }
 
-var (
-	typeCacheLock     sync.RWMutex
-	encodeFieldsCache = make(map[reflect.Type][]encodeField)
-)
+// byName sorts field by name, breaking ties with depth,
+// then breaking ties with "name came from json tag", then
+// breaking ties with index sequence.
+type byName []field
 
-// encodeFields returns a slice of encodeField for a given
-// struct type.
-func encodeFields(t reflect.Type) []encodeField {
-	typeCacheLock.RLock()
-	fs, ok := encodeFieldsCache[t]
-	typeCacheLock.RUnlock()
-	if ok {
-		return fs
-	}
+func (x byName) Len() int { return len(x) }
+
+func (x byName) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
 
-	typeCacheLock.Lock()
-	defer typeCacheLock.Unlock()
-	fs, ok = encodeFieldsCache[t]
-	if ok {
-		return fs
+func (x byName) Less(i, j int) bool {
+	if x[i].name != x[j].name {
+		return x[i].name < x[j].name
 	}
+	if len(x[i].index) != len(x[j].index) {
+		return len(x[i].index) < len(x[j].index)
+	}
+	if x[i].tag != x[j].tag {
+		return x[i].tag
+	}
+	return byIndex(x).Less(i, j)
+}
 
-	v := reflect.Zero(t)
-	n := v.NumField()
-	for i := 0; i < n; i++ {
-		f := t.Field(i)
-		if f.PkgPath != "" {
-			continue
+// byIndex sorts field by index sequence.
+type byIndex []field
+
+func (x byIndex) Len() int { return len(x) }
+
+func (x byIndex) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+
+func (x byIndex) Less(i, j int) bool {
+	for k, xik := range x[i].index {
+		if k >= len(x[j].index) {
+			return false
 		}
-		if f.Anonymous {
-			// We want to do a better job with these later,
-			// so for now pretend they don't exist.
-			continue
+		if xik != x[j].index[k] {
+			return xik < x[j].index[k]
 		}
-		var ef encodeField
-		ef.i = i
-		ef.tag = f.Name
+	}
+	return len(x[i].index) < len(x[j].index)
+}
+
+// typeFields returns a list of fields that JSON should recognize for the given type.
+// The algorithm is breadth-first search over the set of structs to include - the top struct
+// and then any reachable anonymous structs.
+func typeFields(t reflect.Type) []field {
+	// Anonymous fields to explore at the current level and the next.
+	current := []field{}
+	next := []field{{typ: t}}
+
+	// Count of queued names for current level and the next.
+	count := map[reflect.Type]int{}
+	nextCount := map[reflect.Type]int{}
+
+	// Types already visited at an earlier level.
+	visited := map[reflect.Type]bool{}
+
+	// Fields found.
+	var fields []field
+
+	for len(next) > 0 {
+		current, next = next, current[:0]
+		count, nextCount = nextCount, map[reflect.Type]int{}
 
-		tv := f.Tag.Get("json")
-		if tv != "" {
-			if tv == "-" {
+		for _, f := range current {
+			if visited[f.typ] {
 				continue
 			}
-			name, opts := parseTag(tv)
-			if isValidTag(name) {
-				ef.tag = name
+			visited[f.typ] = true
+
+			// Scan f.typ for fields to include.
+			for i := 0; i < f.typ.NumField(); i++ {
+				sf := f.typ.Field(i)
+				if sf.PkgPath != "" { // unexported
+					continue
+				}
+				tag := sf.Tag.Get("json")
+				if tag == "-" {
+					continue
+				}
+				name, opts := parseTag(tag)
+				if !isValidTag(name) {
+					name = ""
+				}
+				index := make([]int, len(f.index)+1)
+				copy(index, f.index)
+				index[len(f.index)] = i
+				// Record found field and index sequence.
+				if name != "" || !sf.Anonymous {
+					tagged := name != ""
+					if name == "" {
+						name = sf.Name
+					}
+					fields = append(fields, field{name, tagged, index, sf.Type,
+						opts.Contains("omitempty"), opts.Contains("string")})
+					if count[f.typ] > 1 {
+						// If there were multiple instances, add a second,
+						// so that the annihilation code will see a duplicate.
+						// It only cares about the distinction between 1 or 2,
+						// so don't bother generating any more copies.
+						fields = append(fields, fields[len(fields)-1])
+					}
+					continue
+				}
+
+				// Record new anonymous struct to explore in next round.
+				ft := sf.Type
+				if ft.Name() == "" {
+					// Must be pointer.
+					ft = ft.Elem()
+				}
+				nextCount[ft]++
+				if nextCount[ft] == 1 {
+					next = append(next, field{name: ft.Name(), index: index, typ: ft})
+				}
 			}
-			ef.omitEmpty = opts.Contains("omitempty")
-			ef.quoted = opts.Contains("string")
 		}
-		fs = append(fs, ef)
 	}
-	encodeFieldsCache[t] = fs
-	return fs
+
+	sort.Sort(byName(fields))
+
+	// Remove fields with annihilating name collisions
+	// and also fields shadowed by fields with explicit JSON tags.
+	name := ""
+	out := fields[:0]
+	for _, f := range fields {
+		if f.name != name {
+			name = f.name
+			out = append(out, f)
+			continue
+		}
+		if n := len(out); n > 0 && out[n-1].name == name && (!out[n-1].tag || f.tag) {
+			out = out[:n-1]
+		}
+	}
+	fields = out
+
+	sort.Sort(byIndex(fields))
+
+	return fields
+}
+
+var fieldCache struct {
+	sync.RWMutex
+	m map[reflect.Type][]field
+}
+
+// cachedTypeFields is like typeFields but uses a cache to avoid repeated work.
+func cachedTypeFields(t reflect.Type) []field {
+	fieldCache.RLock()
+	f := fieldCache.m[t]
+	fieldCache.RUnlock()
+	if f != nil {
+		return f
+	}
+
+	// Compute fields without lock.
+	// Might duplicate effort but won't hold other computations back.
+	f = typeFields(t)
+	if f == nil {
+		f = []field{}
+	}
+
+	fieldCache.Lock()
+	if fieldCache.m == nil {
+		fieldCache.m = map[reflect.Type][]field{}
+	}
+	fieldCache.m[t] = f
+	fieldCache.Unlock()
+	return f
 }
diff --git a/libgo/go/encoding/json/stream.go b/libgo/go/encoding/json/stream.go
index 7d1cc5f119c..9592467d25b 100644
--- a/libgo/go/encoding/json/stream.go
+++ b/libgo/go/encoding/json/stream.go
@@ -26,6 +26,10 @@ func NewDecoder(r io.Reader) *Decoder {
 	return &Decoder{r: r}
 }
 
+// UseNumber causes the Decoder to unmarshal a number into an interface{} as a
+// Number instead of as a float64.
+func (dec *Decoder) UseNumber() { dec.d.useNumber = true }
+
 // Decode reads the next JSON-encoded value from its
 // input and stores it in the value pointed to by v.
 //
@@ -74,7 +78,7 @@ Input:
 			// scanEnd is delayed one byte.
 			// We might block trying to get that byte from src,
 			// so instead invent a space byte.
-			if v == scanEndObject && dec.scan.step(&dec.scan, ' ') == scanEnd {
+			if (v == scanEndObject || v == scanEndArray) && dec.scan.step(&dec.scan, ' ') == scanEnd {
 				scanp += i + 1
 				break Input
 			}
diff --git a/libgo/go/encoding/json/stream_test.go b/libgo/go/encoding/json/stream_test.go
index ce5a7e6d656..4d66f556767 100644
--- a/libgo/go/encoding/json/stream_test.go
+++ b/libgo/go/encoding/json/stream_test.go
@@ -6,6 +6,7 @@ package json
 
 import (
 	"bytes"
+	"net"
 	"reflect"
 	"testing"
 )
@@ -145,3 +146,24 @@ func TestNullRawMessage(t *testing.T) {
 		t.Fatalf("Marshal: have %#q want %#q", b, msg)
 	}
 }
+
+var blockingTests = []string{
+	`{"x": 1}`,
+	`[1, 2, 3]`,
+}
+
+func TestBlocking(t *testing.T) {
+	for _, enc := range blockingTests {
+		r, w := net.Pipe()
+		go w.Write([]byte(enc))
+		var val interface{}
+
+		// If Decode reads beyond what w.Write writes above,
+		// it will block, and the test will deadlock.
+		if err := NewDecoder(r).Decode(&val); err != nil {
+			t.Errorf("decoding %s: %v", enc, err)
+		}
+		r.Close()
+		w.Close()
+	}
+}
diff --git a/libgo/go/encoding/xml/marshal.go b/libgo/go/encoding/xml/marshal.go
index 6c3170bdda3..8592a0c15cb 100644
--- a/libgo/go/encoding/xml/marshal.go
+++ b/libgo/go/encoding/xml/marshal.go
@@ -57,8 +57,8 @@ const (
 //       if the field value is empty. The empty values are false, 0, any
 //       nil pointer or interface value, and any array, slice, map, or
 //       string of length zero.
-//     - a non-pointer anonymous struct field is handled as if the
-//       fields of its value were part of the outer struct.
+//     - an anonymous struct field is handled as if the fields of its
+//       value were part of the outer struct.
 //
 // If a field uses a tag "a>b>c", then the element c will be nested inside
 // parent elements a and b.  Fields that appear next to each other that name
@@ -83,9 +83,7 @@ func MarshalIndent(v interface{}, prefix, indent string) ([]byte, error) {
 	enc := NewEncoder(&b)
 	enc.prefix = prefix
 	enc.indent = indent
-	err := enc.marshalValue(reflect.ValueOf(v), nil)
-	enc.Flush()
-	if err != nil {
+	if err := enc.Encode(v); err != nil {
 		return nil, err
 	}
 	return b.Bytes(), nil
@@ -107,8 +105,10 @@ func NewEncoder(w io.Writer) *Encoder {
 // of Go values to XML.
 func (enc *Encoder) Encode(v interface{}) error {
 	err := enc.marshalValue(reflect.ValueOf(v), nil)
-	enc.Flush()
-	return err
+	if err != nil {
+		return err
+	}
+	return enc.Flush()
 }
 
 type printer struct {
@@ -164,7 +164,7 @@ func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo) error {
 		xmlname := tinfo.xmlname
 		if xmlname.name != "" {
 			xmlns, name = xmlname.xmlns, xmlname.name
-		} else if v, ok := val.FieldByIndex(xmlname.idx).Interface().(Name); ok && v.Local != "" {
+		} else if v, ok := xmlname.value(val).Interface().(Name); ok && v.Local != "" {
 			xmlns, name = v.Space, v.Local
 		}
 	}
@@ -195,7 +195,7 @@ func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo) error {
 		if finfo.flags&fAttr == 0 {
 			continue
 		}
-		fv := val.FieldByIndex(finfo.idx)
+		fv := finfo.value(val)
 		if finfo.flags&fOmitEmpty != 0 && isEmptyValue(fv) {
 			continue
 		}
@@ -224,7 +224,7 @@ func (p *printer) marshalValue(val reflect.Value, finfo *fieldInfo) error {
 	p.WriteString(name)
 	p.WriteByte('>')
 
-	return nil
+	return p.cachedWriteError()
 }
 
 var timeType = reflect.TypeOf(time.Time{})
@@ -260,15 +260,15 @@ func (p *printer) marshalSimple(typ reflect.Type, val reflect.Value) error {
 	default:
 		return &UnsupportedTypeError{typ}
 	}
-	return nil
+	return p.cachedWriteError()
 }
 
 var ddBytes = []byte("--")
 
 func (p *printer) marshalStruct(tinfo *typeInfo, val reflect.Value) error {
 	if val.Type() == timeType {
-		p.WriteString(val.Interface().(time.Time).Format(time.RFC3339Nano))
-		return nil
+		_, err := p.WriteString(val.Interface().(time.Time).Format(time.RFC3339Nano))
+		return err
 	}
 	s := parentStack{printer: p}
 	for i := range tinfo.fields {
@@ -276,7 +276,7 @@ func (p *printer) marshalStruct(tinfo *typeInfo, val reflect.Value) error {
 		if finfo.flags&(fAttr|fAny) != 0 {
 			continue
 		}
-		vf := val.FieldByIndex(finfo.idx)
+		vf := finfo.value(val)
 		switch finfo.flags & fMode {
 		case fCharData:
 			switch vf.Kind() {
@@ -353,7 +353,13 @@ func (p *printer) marshalStruct(tinfo *typeInfo, val reflect.Value) error {
 		}
 	}
 	s.trim(nil)
-	return nil
+	return p.cachedWriteError()
+}
+
+// return the bufio Writer's cached write error
+func (p *printer) cachedWriteError() error {
+	_, err := p.Write(nil)
+	return err
 }
 
 func (p *printer) writeIndent(depthDelta int) {
diff --git a/libgo/go/encoding/xml/marshal_test.go b/libgo/go/encoding/xml/marshal_test.go
index b6978a1e65b..e729a247af4 100644
--- a/libgo/go/encoding/xml/marshal_test.go
+++ b/libgo/go/encoding/xml/marshal_test.go
@@ -5,6 +5,9 @@
 package xml
 
 import (
+	"bytes"
+	"errors"
+	"io"
 	"reflect"
 	"strconv"
 	"strings"
@@ -108,7 +111,7 @@ type EmbedA struct {
 
 type EmbedB struct {
 	FieldB string
-	EmbedC
+	*EmbedC
 }
 
 type EmbedC struct {
@@ -493,7 +496,7 @@ var marshalTests = []struct {
 			},
 			EmbedB: EmbedB{
 				FieldB: "A.B.B",
-				EmbedC: EmbedC{
+				EmbedC: &EmbedC{
 					FieldA1: "A.B.C.A1",
 					FieldA2: "A.B.C.A2",
 					FieldB:  "", // Shadowed by A.B.B
@@ -779,6 +782,55 @@ func TestUnmarshal(t *testing.T) {
 	}
 }
 
+type limitedBytesWriter struct {
+	w      io.Writer
+	remain int // until writes fail
+}
+
+func (lw *limitedBytesWriter) Write(p []byte) (n int, err error) {
+	if lw.remain <= 0 {
+		println("error")
+		return 0, errors.New("write limit hit")
+	}
+	if len(p) > lw.remain {
+		p = p[:lw.remain]
+		n, _ = lw.w.Write(p)
+		lw.remain = 0
+		return n, errors.New("write limit hit")
+	}
+	n, err = lw.w.Write(p)
+	lw.remain -= n
+	return n, err
+}
+
+func TestMarshalWriteErrors(t *testing.T) {
+	var buf bytes.Buffer
+	const writeCap = 1024
+	w := &limitedBytesWriter{&buf, writeCap}
+	enc := NewEncoder(w)
+	var err error
+	var i int
+	const n = 4000
+	for i = 1; i <= n; i++ {
+		err = enc.Encode(&Passenger{
+			Name:   []string{"Alice", "Bob"},
+			Weight: 5,
+		})
+		if err != nil {
+			break
+		}
+	}
+	if err == nil {
+		t.Error("expected an error")
+	}
+	if i == n {
+		t.Errorf("expected to fail before the end")
+	}
+	if buf.Len() != writeCap {
+		t.Errorf("buf.Len() = %d; want %d", buf.Len(), writeCap)
+	}
+}
+
 func BenchmarkMarshal(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		Marshal(atomValue)
diff --git a/libgo/go/encoding/xml/read.go b/libgo/go/encoding/xml/read.go
index c2168242091..0e6761d66ad 100644
--- a/libgo/go/encoding/xml/read.go
+++ b/libgo/go/encoding/xml/read.go
@@ -81,8 +81,8 @@ import (
 //      of the above rules and the struct has a field with tag ",any",
 //      unmarshal maps the sub-element to that struct field.
 //
-//   * A non-pointer anonymous struct field is handled as if the
-//      fields of its value were part of the outer struct.
+//   * An anonymous struct field is handled as if the fields of its
+//      value were part of the outer struct.
 //
 //   * A struct field with tag "-" is never unmarshalled into.
 //
@@ -248,7 +248,7 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 				}
 				return UnmarshalError(e)
 			}
-			fv := sv.FieldByIndex(finfo.idx)
+			fv := finfo.value(sv)
 			if _, ok := fv.Interface().(Name); ok {
 				fv.Set(reflect.ValueOf(start.Name))
 			}
@@ -260,7 +260,7 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 			finfo := &tinfo.fields[i]
 			switch finfo.flags & fMode {
 			case fAttr:
-				strv := sv.FieldByIndex(finfo.idx)
+				strv := finfo.value(sv)
 				// Look for attribute.
 				for _, a := range start.Attr {
 					if a.Name.Local == finfo.name {
@@ -271,22 +271,22 @@ func (p *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 
 			case fCharData:
 				if !saveData.IsValid() {
-					saveData = sv.FieldByIndex(finfo.idx)
+					saveData = finfo.value(sv)
 				}
 
 			case fComment:
 				if !saveComment.IsValid() {
-					saveComment = sv.FieldByIndex(finfo.idx)
+					saveComment = finfo.value(sv)
 				}
 
 			case fAny:
 				if !saveAny.IsValid() {
-					saveAny = sv.FieldByIndex(finfo.idx)
+					saveAny = finfo.value(sv)
 				}
 
 			case fInnerXml:
 				if !saveXML.IsValid() {
-					saveXML = sv.FieldByIndex(finfo.idx)
+					saveXML = finfo.value(sv)
 					if p.saved == nil {
 						saveXMLIndex = 0
 						p.saved = new(bytes.Buffer)
@@ -461,7 +461,7 @@ Loop:
 		}
 		if len(finfo.parents) == len(parents) && finfo.name == start.Name.Local {
 			// It's a perfect match, unmarshal the field.
-			return true, p.unmarshal(sv.FieldByIndex(finfo.idx), start)
+			return true, p.unmarshal(finfo.value(sv), start)
 		}
 		if len(finfo.parents) > len(parents) && finfo.parents[len(parents)] == start.Name.Local {
 			// It's a prefix for the field. Break and recurse
diff --git a/libgo/go/encoding/xml/typeinfo.go b/libgo/go/encoding/xml/typeinfo.go
index 8e2e4508b10..970d1701932 100644
--- a/libgo/go/encoding/xml/typeinfo.go
+++ b/libgo/go/encoding/xml/typeinfo.go
@@ -66,10 +66,14 @@ func getTypeInfo(typ reflect.Type) (*typeInfo, error) {
 
 			// For embedded structs, embed its fields.
 			if f.Anonymous {
-				if f.Type.Kind() != reflect.Struct {
+				t := f.Type
+				if t.Kind() == reflect.Ptr {
+					t = t.Elem()
+				}
+				if t.Kind() != reflect.Struct {
 					continue
 				}
-				inner, err := getTypeInfo(f.Type)
+				inner, err := getTypeInfo(t)
 				if err != nil {
 					return nil, err
 				}
@@ -327,3 +331,22 @@ type TagPathError struct {
 func (e *TagPathError) Error() string {
 	return fmt.Sprintf("%s field %q with tag %q conflicts with field %q with tag %q", e.Struct, e.Field1, e.Tag1, e.Field2, e.Tag2)
 }
+
+// value returns v's field value corresponding to finfo.
+// It's equivalent to v.FieldByIndex(finfo.idx), but initializes
+// and dereferences pointers as necessary.
+func (finfo *fieldInfo) value(v reflect.Value) reflect.Value {
+	for i, x := range finfo.idx {
+		if i > 0 {
+			t := v.Type()
+			if t.Kind() == reflect.Ptr && t.Elem().Kind() == reflect.Struct {
+				if v.IsNil() {
+					v.Set(reflect.New(v.Type().Elem()))
+				}
+				v = v.Elem()
+			}
+		}
+		v = v.Field(x)
+	}
+	return v
+}
diff --git a/libgo/go/encoding/xml/xml.go b/libgo/go/encoding/xml/xml.go
index 5066f5c0106..fbd2208e334 100644
--- a/libgo/go/encoding/xml/xml.go
+++ b/libgo/go/encoding/xml/xml.go
@@ -584,6 +584,7 @@ func (d *Decoder) RawToken() (Token, error) {
 			if inquote == 0 && b == '>' && depth == 0 {
 				break
 			}
+		HandleB:
 			d.buf.WriteByte(b)
 			switch {
 			case b == inquote:
@@ -599,7 +600,35 @@ func (d *Decoder) RawToken() (Token, error) {
 				depth--
 
 			case b == '<' && inquote == 0:
-				depth++
+				// Look for <!-- to begin comment.
+				s := "!--"
+				for i := 0; i < len(s); i++ {
+					if b, ok = d.mustgetc(); !ok {
+						return nil, d.err
+					}
+					if b != s[i] {
+						for j := 0; j < i; j++ {
+							d.buf.WriteByte(s[j])
+						}
+						depth++
+						goto HandleB
+					}
+				}
+
+				// Remove < that was written above.
+				d.buf.Truncate(d.buf.Len() - 1)
+
+				// Look for terminator.
+				var b0, b1 byte
+				for {
+					if b, ok = d.mustgetc(); !ok {
+						return nil, d.err
+					}
+					if b0 == '-' && b1 == '-' && b == '>' {
+						break
+					}
+					b0, b1 = b1, b
+				}
 			}
 		}
 		return Directive(d.buf.Bytes()), nil
@@ -850,6 +879,8 @@ Input:
 			// Parsers are required to recognize lt, gt, amp, apos, and quot
 			// even if they have not been declared.  That's all we allow.
 			var i int
+			var semicolon bool
+			var valid bool
 			for i = 0; i < len(d.tmp); i++ {
 				var ok bool
 				d.tmp[i], ok = d.getc()
@@ -861,6 +892,8 @@ Input:
 				}
 				c := d.tmp[i]
 				if c == ';' {
+					semicolon = true
+					valid = i > 0
 					break
 				}
 				if 'a' <= c && c <= 'z' ||
@@ -873,14 +906,25 @@ Input:
 				break
 			}
 			s := string(d.tmp[0:i])
-			if i >= len(d.tmp) {
+			if !valid {
 				if !d.Strict {
 					b0, b1 = 0, 0
 					d.buf.WriteByte('&')
 					d.buf.Write(d.tmp[0:i])
+					if semicolon {
+						d.buf.WriteByte(';')
+					}
 					continue Input
 				}
-				d.err = d.syntaxError("character entity expression &" + s + "... too long")
+				semi := ";"
+				if !semicolon {
+					semi = " (no semicolon)"
+				}
+				if i < len(d.tmp) {
+					d.err = d.syntaxError("invalid character entity &" + s + semi)
+				} else {
+					d.err = d.syntaxError("invalid character entity &" + s + "... too long")
+				}
 				return nil
 			}
 			var haveText bool
@@ -910,6 +954,7 @@ Input:
 					b0, b1 = 0, 0
 					d.buf.WriteByte('&')
 					d.buf.Write(d.tmp[0:i])
+					d.buf.WriteByte(';')
 					continue Input
 				}
 				d.err = d.syntaxError("invalid character entity &" + s + ";")
diff --git a/libgo/go/encoding/xml/xml_test.go b/libgo/go/encoding/xml/xml_test.go
index 1d0696ce087..2ad4d4af5df 100644
--- a/libgo/go/encoding/xml/xml_test.go
+++ b/libgo/go/encoding/xml/xml_test.go
@@ -5,6 +5,7 @@
 package xml
 
 import (
+	"fmt"
 	"io"
 	"reflect"
 	"strings"
@@ -158,6 +159,39 @@ func TestRawToken(t *testing.T) {
 	testRawToken(t, d, rawTokens)
 }
 
+const nonStrictInput = `
+<tag>non&entity</tag>
+<tag>&unknown;entity</tag>
+<tag>&#123</tag>
+<tag>&#zzz;</tag>
+`
+
+var nonStrictTokens = []Token{
+	CharData("\n"),
+	StartElement{Name{"", "tag"}, []Attr{}},
+	CharData("non&entity"),
+	EndElement{Name{"", "tag"}},
+	CharData("\n"),
+	StartElement{Name{"", "tag"}, []Attr{}},
+	CharData("&unknown;entity"),
+	EndElement{Name{"", "tag"}},
+	CharData("\n"),
+	StartElement{Name{"", "tag"}, []Attr{}},
+	CharData("&#123"),
+	EndElement{Name{"", "tag"}},
+	CharData("\n"),
+	StartElement{Name{"", "tag"}, []Attr{}},
+	CharData("&#zzz;"),
+	EndElement{Name{"", "tag"}},
+	CharData("\n"),
+}
+
+func TestNonStrictRawToken(t *testing.T) {
+	d := NewDecoder(strings.NewReader(nonStrictInput))
+	d.Strict = false
+	testRawToken(t, d, nonStrictTokens)
+}
+
 type downCaser struct {
 	t *testing.T
 	r io.ByteReader
@@ -219,7 +253,18 @@ func testRawToken(t *testing.T, d *Decoder, rawTokens []Token) {
 			t.Fatalf("token %d: unexpected error: %s", i, err)
 		}
 		if !reflect.DeepEqual(have, want) {
-			t.Errorf("token %d = %#v want %#v", i, have, want)
+			var shave, swant string
+			if _, ok := have.(CharData); ok {
+				shave = fmt.Sprintf("CharData(%q)", have)
+			} else {
+				shave = fmt.Sprintf("%#v", have)
+			}
+			if _, ok := want.(CharData); ok {
+				swant = fmt.Sprintf("CharData(%q)", want)
+			} else {
+				swant = fmt.Sprintf("%#v", want)
+			}
+			t.Errorf("token %d = %s, want %s", i, shave, swant)
 		}
 	}
 }
@@ -531,8 +576,8 @@ var characterTests = []struct {
 	{"\xef\xbf\xbe<doc/>", "illegal character code U+FFFE"},
 	{"<?xml version=\"1.0\"?><doc>\r\n<hiya/>\x07<toots/></doc>", "illegal character code U+0007"},
 	{"<?xml version=\"1.0\"?><doc \x12='value'>what's up</doc>", "expected attribute name in element"},
-	{"<doc>&\x01;</doc>", "invalid character entity &;"},
-	{"<doc>&\xef\xbf\xbe;</doc>", "invalid character entity &;"},
+	{"<doc>&\x01;</doc>", "invalid character entity & (no semicolon)"},
+	{"<doc>&\xef\xbf\xbe;</doc>", "invalid character entity & (no semicolon)"},
 }
 
 func TestDisallowedCharacters(t *testing.T) {
@@ -576,3 +621,36 @@ func TestProcInstEncoding(t *testing.T) {
 		}
 	}
 }
+
+// Ensure that directives with comments include the complete
+// text of any nested directives.
+
+var directivesWithCommentsInput = `
+<!DOCTYPE [<!-- a comment --><!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#">]>
+<!DOCTYPE [<!ENTITY go "Golang"><!-- a comment-->]>
+<!DOCTYPE <!-> <!> <!----> <!-->--> <!--->--> [<!ENTITY go "Golang"><!-- a comment-->]>
+`
+
+var directivesWithCommentsTokens = []Token{
+	CharData("\n"),
+	Directive(`DOCTYPE [<!ENTITY rdf "http://www.w3.org/1999/02/22-rdf-syntax-ns#">]`),
+	CharData("\n"),
+	Directive(`DOCTYPE [<!ENTITY go "Golang">]`),
+	CharData("\n"),
+	Directive(`DOCTYPE <!-> <!>    [<!ENTITY go "Golang">]`),
+	CharData("\n"),
+}
+
+func TestDirectivesWithComments(t *testing.T) {
+	d := NewDecoder(strings.NewReader(directivesWithCommentsInput))
+
+	for i, want := range directivesWithCommentsTokens {
+		have, err := d.Token()
+		if err != nil {
+			t.Fatalf("token %d: unexpected error: %s", i, err)
+		}
+		if !reflect.DeepEqual(have, want) {
+			t.Errorf("token %d = %#v want %#v", i, have, want)
+		}
+	}
+}