libgo: update to Go1.14beta1

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/214297

27 files changed, 946 insertions, 277 deletions

diff --git a/libgo/go/encoding/asn1/asn1.go b/libgo/go/encoding/asn1/asn1.go
index 3cfd9d1..fd4dd68 100644
--- a/libgo/go/encoding/asn1/asn1.go
+++ b/libgo/go/encoding/asn1/asn1.go
@@ -27,6 +27,7 @@ import (
 	"reflect"
 	"strconv"
 	"time"
+	"unicode/utf16"
 	"unicode/utf8"
 )
 
@@ -475,6 +476,29 @@ func parseUTF8String(bytes []byte) (ret string, err error) {
 	return string(bytes), nil
 }
 
+// BMPString
+
+// parseBMPString parses an ASN.1 BMPString (Basic Multilingual Plane of
+// ISO/IEC/ITU 10646-1) from the given byte slice and returns it.
+func parseBMPString(bmpString []byte) (string, error) {
+	if len(bmpString)%2 != 0 {
+		return "", errors.New("pkcs12: odd-length BMP string")
+	}
+
+	// Strip terminator if present.
+	if l := len(bmpString); l >= 2 && bmpString[l-1] == 0 && bmpString[l-2] == 0 {
+		bmpString = bmpString[:l-2]
+	}
+
+	s := make([]uint16, 0, len(bmpString)/2)
+	for len(bmpString) > 0 {
+		s = append(s, uint16(bmpString[0])<<8+uint16(bmpString[1]))
+		bmpString = bmpString[2:]
+	}
+
+	return string(utf16.Decode(s)), nil
+}
+
 // A RawValue represents an undecoded ASN.1 object.
 type RawValue struct {
 	Class, Tag int
@@ -589,7 +613,7 @@ func parseSequenceOf(bytes []byte, sliceType reflect.Type, elemType reflect.Type
 			return
 		}
 		switch t.tag {
-		case TagIA5String, TagGeneralString, TagT61String, TagUTF8String, TagNumericString:
+		case TagIA5String, TagGeneralString, TagT61String, TagUTF8String, TagNumericString, TagBMPString:
 			// We pretend that various other string types are
 			// PRINTABLE STRINGs so that a sequence of them can be
 			// parsed into a []string.
@@ -691,6 +715,8 @@ func parseField(v reflect.Value, bytes []byte, initOffset int, params fieldParam
 				result, err = parseGeneralizedTime(innerBytes)
 			case TagOctetString:
 				result = innerBytes
+			case TagBMPString:
+				result, err = parseBMPString(innerBytes)
 			default:
 				// If we don't know how to handle the type, we just leave Value as nil.
 			}
@@ -759,7 +785,7 @@ func parseField(v reflect.Value, bytes []byte, initOffset int, params fieldParam
 	if universalTag == TagPrintableString {
 		if t.class == ClassUniversal {
 			switch t.tag {
-			case TagIA5String, TagGeneralString, TagT61String, TagUTF8String, TagNumericString:
+			case TagIA5String, TagGeneralString, TagT61String, TagUTF8String, TagNumericString, TagBMPString:
 				universalTag = t.tag
 			}
 		} else if params.stringType != 0 {
@@ -957,6 +983,9 @@ func parseField(v reflect.Value, bytes []byte, initOffset int, params fieldParam
 			// that allow the encoding to change midstring and
 			// such. We give up and pass it as an 8-bit string.
 			v, err = parseT61String(innerBytes)
+		case TagBMPString:
+			v, err = parseBMPString(innerBytes)
+
 		default:
 			err = SyntaxError{fmt.Sprintf("internal error: unknown string type %d", universalTag)}
 		}
diff --git a/libgo/go/encoding/asn1/asn1_test.go b/libgo/go/encoding/asn1/asn1_test.go
index f0a54e0..d5649bf 100644
--- a/libgo/go/encoding/asn1/asn1_test.go
+++ b/libgo/go/encoding/asn1/asn1_test.go
@@ -6,6 +6,7 @@ package asn1
 
 import (
 	"bytes"
+	"encoding/hex"
 	"fmt"
 	"math"
 	"math/big"
@@ -1096,3 +1097,35 @@ func TestTaggedRawValue(t *testing.T) {
 		}
 	}
 }
+
+var bmpStringTests = []struct {
+	decoded    string
+	encodedHex string
+}{
+	{"", "0000"},
+	// Example from https://tools.ietf.org/html/rfc7292#appendix-B.
+	{"Beavis", "0042006500610076006900730000"},
+	// Some characters from the "Letterlike Symbols Unicode block".
+	{"\u2115 - Double-struck N", "21150020002d00200044006f00750062006c0065002d00730074007200750063006b0020004e0000"},
+}
+
+func TestBMPString(t *testing.T) {
+	for i, test := range bmpStringTests {
+		encoded, err := hex.DecodeString(test.encodedHex)
+		if err != nil {
+			t.Fatalf("#%d: failed to decode from hex string", i)
+		}
+
+		decoded, err := parseBMPString(encoded)
+
+		if err != nil {
+			t.Errorf("#%d: decoding output gave an error: %s", i, err)
+			continue
+		}
+
+		if decoded != test.decoded {
+			t.Errorf("#%d: decoding output resulted in %q, but it should have been %q", i, decoded, test.decoded)
+			continue
+		}
+	}
+}
diff --git a/libgo/go/encoding/asn1/common.go b/libgo/go/encoding/asn1/common.go
index 255d1eb..e2aa8bd 100644
--- a/libgo/go/encoding/asn1/common.go
+++ b/libgo/go/encoding/asn1/common.go
@@ -37,6 +37,7 @@ const (
 	TagUTCTime         = 23
 	TagGeneralizedTime = 24
 	TagGeneralString   = 27
+	TagBMPString       = 30
 )
 
 // ASN.1 class types represent the namespace of the tag.
diff --git a/libgo/go/encoding/base32/base32.go b/libgo/go/encoding/base32/base32.go
index e14d2d4..2f7d363 100644
--- a/libgo/go/encoding/base32/base32.go
+++ b/libgo/go/encoding/base32/base32.go
@@ -6,10 +6,8 @@
 package base32
 
 import (
-	"bytes"
 	"io"
 	"strconv"
-	"strings"
 )
 
 /*
@@ -62,13 +60,6 @@ var StdEncoding = NewEncoding(encodeStd)
 // It is typically used in DNS.
 var HexEncoding = NewEncoding(encodeHex)
 
-var removeNewlinesMapper = func(r rune) rune {
-	if r == '\r' || r == '\n' {
-		return -1
-	}
-	return r
-}
-
 // WithPadding creates a new encoding identical to enc except
 // with a specified padding character, or NoPadding to disable padding.
 // The padding character must not be '\r' or '\n', must not
@@ -302,7 +293,7 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 					// We have reached the end and are missing padding
 					return n, false, CorruptInputError(olen - len(src) - j)
 				}
-				// We have reached the end and are not expecing any padding
+				// We have reached the end and are not expecting any padding
 				dlen, end = j, true
 				break
 			}
@@ -372,17 +363,18 @@ func (enc *Encoding) decode(dst, src []byte) (n int, end bool, err error) {
 // number of bytes successfully written and CorruptInputError.
 // New line characters (\r and \n) are ignored.
 func (enc *Encoding) Decode(dst, src []byte) (n int, err error) {
-	src = bytes.Map(removeNewlinesMapper, src)
-	n, _, err = enc.decode(dst, src)
+	buf := make([]byte, len(src))
+	l := stripNewlines(buf, src)
+	n, _, err = enc.decode(dst, buf[:l])
 	return
 }
 
 // DecodeString returns the bytes represented by the base32 string s.
 func (enc *Encoding) DecodeString(s string) ([]byte, error) {
-	s = strings.Map(removeNewlinesMapper, s)
-	dbuf := make([]byte, enc.DecodedLen(len(s)))
-	n, _, err := enc.decode(dbuf, []byte(s))
-	return dbuf[:n], err
+	buf := []byte(s)
+	l := stripNewlines(buf, buf)
+	n, _, err := enc.decode(buf, buf[:l])
+	return buf[:n], err
 }
 
 type decoder struct {
@@ -497,18 +489,25 @@ type newlineFilteringReader struct {
 	wrapped io.Reader
 }
 
+// stripNewlines removes newline characters and returns the number
+// of non-newline characters copied to dst.
+func stripNewlines(dst, src []byte) int {
+	offset := 0
+	for _, b := range src {
+		if b == '\r' || b == '\n' {
+			continue
+		}
+		dst[offset] = b
+		offset++
+	}
+	return offset
+}
+
 func (r *newlineFilteringReader) Read(p []byte) (int, error) {
 	n, err := r.wrapped.Read(p)
 	for n > 0 {
-		offset := 0
-		for i, b := range p[0:n] {
-			if b != '\r' && b != '\n' {
-				if i != offset {
-					p[offset] = b
-				}
-				offset++
-			}
-		}
+		s := p[0:n]
+		offset := stripNewlines(s, s)
 		if err != nil || offset > 0 {
 			return offset, err
 		}
diff --git a/libgo/go/encoding/base32/base32_test.go b/libgo/go/encoding/base32/base32_test.go
index eb14f1e..0b611db 100644
--- a/libgo/go/encoding/base32/base32_test.go
+++ b/libgo/go/encoding/base32/base32_test.go
@@ -445,6 +445,15 @@ LNEBUWIIDFON2CA3DBMJXXE5LNFY==
 	}
 }
 
+func BenchmarkEncode(b *testing.B) {
+	data := make([]byte, 8192)
+	buf := make([]byte, StdEncoding.EncodedLen(len(data)))
+	b.SetBytes(int64(len(data)))
+	for i := 0; i < b.N; i++ {
+		StdEncoding.Encode(buf, data)
+	}
+}
+
 func BenchmarkEncodeToString(b *testing.B) {
 	data := make([]byte, 8192)
 	b.SetBytes(int64(len(data)))
@@ -453,6 +462,15 @@ func BenchmarkEncodeToString(b *testing.B) {
 	}
 }
 
+func BenchmarkDecode(b *testing.B) {
+	data := make([]byte, StdEncoding.EncodedLen(8192))
+	StdEncoding.Encode(data, make([]byte, 8192))
+	buf := make([]byte, 8192)
+	b.SetBytes(int64(len(data)))
+	for i := 0; i < b.N; i++ {
+		StdEncoding.Decode(buf, data)
+	}
+}
 func BenchmarkDecodeString(b *testing.B) {
 	data := StdEncoding.EncodeToString(make([]byte, 8192))
 	b.SetBytes(int64(len(data)))
diff --git a/libgo/go/encoding/base64/base64.go b/libgo/go/encoding/base64/base64.go
index 0822101..690d3ce 100644
--- a/libgo/go/encoding/base64/base64.go
+++ b/libgo/go/encoding/base64/base64.go
@@ -86,6 +86,9 @@ func (enc Encoding) WithPadding(padding rune) *Encoding {
 // Strict creates a new encoding identical to enc except with
 // strict decoding enabled. In this mode, the decoder requires that
 // trailing padding bits are zero, as described in RFC 4648 section 3.5.
+//
+// Note that the input is still malleable, as new line characters
+// (CR and LF) are still ignored.
 func (enc Encoding) Strict() *Encoding {
 	enc.strict = true
 	return &enc
diff --git a/libgo/go/encoding/binary/binary.go b/libgo/go/encoding/binary/binary.go
index 8c2d1d9..a99ca01 100644
--- a/libgo/go/encoding/binary/binary.go
+++ b/libgo/go/encoding/binary/binary.go
@@ -26,6 +26,7 @@ import (
 	"io"
 	"math"
 	"reflect"
+	"sync"
 )
 
 // A ByteOrder specifies how to convert byte sequences into
@@ -184,6 +185,10 @@ func Read(r io.Reader, order ByteOrder, data interface{}) error {
 			*data = int64(order.Uint64(bs))
 		case *uint64:
 			*data = order.Uint64(bs)
+		case *float32:
+			*data = math.Float32frombits(order.Uint32(bs))
+		case *float64:
+			*data = math.Float64frombits(order.Uint64(bs))
 		case []bool:
 			for i, x := range bs { // Easier to loop over the input for 8-bit values.
 				data[i] = x != 0
@@ -218,8 +223,20 @@ func Read(r io.Reader, order ByteOrder, data interface{}) error {
 			for i := range data {
 				data[i] = order.Uint64(bs[8*i:])
 			}
+		case []float32:
+			for i := range data {
+				data[i] = math.Float32frombits(order.Uint32(bs[4*i:]))
+			}
+		case []float64:
+			for i := range data {
+				data[i] = math.Float64frombits(order.Uint64(bs[8*i:]))
+			}
+		default:
+			n = 0 // fast path doesn't apply
+		}
+		if n != 0 {
+			return nil
 		}
-		return nil
 	}
 
 	// Fallback to reflect-based decoding.
@@ -338,6 +355,22 @@ func Write(w io.Writer, order ByteOrder, data interface{}) error {
 			for i, x := range v {
 				order.PutUint64(bs[8*i:], x)
 			}
+		case *float32:
+			order.PutUint32(bs, math.Float32bits(*v))
+		case float32:
+			order.PutUint32(bs, math.Float32bits(v))
+		case []float32:
+			for i, x := range v {
+				order.PutUint32(bs[4*i:], math.Float32bits(x))
+			}
+		case *float64:
+			order.PutUint64(bs, math.Float64bits(*v))
+		case float64:
+			order.PutUint64(bs, math.Float64bits(v))
+		case []float64:
+			for i, x := range v {
+				order.PutUint64(bs[8*i:], math.Float64bits(x))
+			}
 		}
 		_, err := w.Write(bs)
 		return err
@@ -363,18 +396,32 @@ func Size(v interface{}) int {
 	return dataSize(reflect.Indirect(reflect.ValueOf(v)))
 }
 
+var structSize sync.Map // map[reflect.Type]int
+
 // dataSize returns the number of bytes the actual data represented by v occupies in memory.
 // For compound structures, it sums the sizes of the elements. Thus, for instance, for a slice
 // it returns the length of the slice times the element size and does not count the memory
 // occupied by the header. If the type of v is not acceptable, dataSize returns -1.
 func dataSize(v reflect.Value) int {
-	if v.Kind() == reflect.Slice {
+	switch v.Kind() {
+	case reflect.Slice:
 		if s := sizeof(v.Type().Elem()); s >= 0 {
 			return s * v.Len()
 		}
 		return -1
+
+	case reflect.Struct:
+		t := v.Type()
+		if size, ok := structSize.Load(t); ok {
+			return size.(int)
+		}
+		size := sizeof(t)
+		structSize.Store(t, size)
+		return size
+
+	default:
+		return sizeof(v.Type())
 	}
-	return sizeof(v.Type())
 }
 
 // sizeof returns the size >= 0 of variables for the given type or -1 if the type is not acceptable.
@@ -677,6 +724,14 @@ func intDataSize(data interface{}) int {
 		return 8 * len(data)
 	case []uint64:
 		return 8 * len(data)
+	case float32, *float32:
+		return 4
+	case float64, *float64:
+		return 8
+	case []float32:
+		return 4 * len(data)
+	case []float64:
+		return 8 * len(data)
 	}
 	return 0
 }
diff --git a/libgo/go/encoding/binary/binary_test.go b/libgo/go/encoding/binary/binary_test.go
index af40257..aeb4212 100644
--- a/libgo/go/encoding/binary/binary_test.go
+++ b/libgo/go/encoding/binary/binary_test.go
@@ -6,10 +6,13 @@ package binary
 
 import (
 	"bytes"
+	"fmt"
 	"io"
+	"io/ioutil"
 	"math"
 	"reflect"
 	"strings"
+	"sync"
 	"testing"
 )
 
@@ -296,6 +299,58 @@ func TestBlankFields(t *testing.T) {
 	}
 }
 
+func TestSizeStructCache(t *testing.T) {
+	// Reset the cache, otherwise multiple test runs fail.
+	structSize = sync.Map{}
+
+	count := func() int {
+		var i int
+		structSize.Range(func(_, _ interface{}) bool {
+			i++
+			return true
+		})
+		return i
+	}
+
+	var total int
+	added := func() int {
+		delta := count() - total
+		total += delta
+		return delta
+	}
+
+	type foo struct {
+		A uint32
+	}
+
+	type bar struct {
+		A Struct
+		B foo
+		C Struct
+	}
+
+	testcases := []struct {
+		val  interface{}
+		want int
+	}{
+		{new(foo), 1},
+		{new(bar), 1},
+		{new(bar), 0},
+		{new(struct{ A Struct }), 1},
+		{new(struct{ A Struct }), 0},
+	}
+
+	for _, tc := range testcases {
+		if Size(tc.val) == -1 {
+			t.Fatalf("Can't get the size of %T", tc.val)
+		}
+
+		if n := added(); n != tc.want {
+			t.Errorf("Sizing %T added %d entries to the cache, want %d", tc.val, n, tc.want)
+		}
+	}
+}
+
 // An attempt to read into a struct with an unexported field will
 // panic. This is probably not the best choice, but at this point
 // anything else would be an API change.
@@ -397,6 +452,35 @@ func TestEarlyBoundsChecks(t *testing.T) {
 	}
 }
 
+func TestReadInvalidDestination(t *testing.T) {
+	testReadInvalidDestination(t, BigEndian)
+	testReadInvalidDestination(t, LittleEndian)
+}
+
+func testReadInvalidDestination(t *testing.T, order ByteOrder) {
+	destinations := []interface{}{
+		int8(0),
+		int16(0),
+		int32(0),
+		int64(0),
+
+		uint8(0),
+		uint16(0),
+		uint32(0),
+		uint64(0),
+
+		bool(false),
+	}
+
+	for _, dst := range destinations {
+		err := Read(bytes.NewReader([]byte{1, 2, 3, 4, 5, 6, 7, 8}), order, dst)
+		want := fmt.Sprintf("binary.Read: invalid type %T", dst)
+		if err == nil || err.Error() != want {
+			t.Fatalf("for type %T: got %q; want %q", dst, err, want)
+		}
+	}
+}
+
 type byteSliceReader struct {
 	remain []byte
 }
@@ -436,6 +520,14 @@ func BenchmarkReadStruct(b *testing.B) {
 	}
 }
 
+func BenchmarkWriteStruct(b *testing.B) {
+	b.SetBytes(int64(Size(&s)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		Write(ioutil.Discard, BigEndian, &s)
+	}
+}
+
 func BenchmarkReadInts(b *testing.B) {
 	var ls Struct
 	bsr := &byteSliceReader{}
@@ -542,3 +634,75 @@ func BenchmarkLittleEndianPutUint64(b *testing.B) {
 		LittleEndian.PutUint64(putbuf[:], uint64(i))
 	}
 }
+
+func BenchmarkReadFloats(b *testing.B) {
+	var ls Struct
+	bsr := &byteSliceReader{}
+	var r io.Reader = bsr
+	b.SetBytes(4 + 8)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bsr.remain = big[30:]
+		Read(r, BigEndian, &ls.Float32)
+		Read(r, BigEndian, &ls.Float64)
+	}
+	b.StopTimer()
+	want := s
+	want.Int8 = 0
+	want.Int16 = 0
+	want.Int32 = 0
+	want.Int64 = 0
+	want.Uint8 = 0
+	want.Uint16 = 0
+	want.Uint32 = 0
+	want.Uint64 = 0
+	want.Complex64 = 0
+	want.Complex128 = 0
+	want.Array = [4]uint8{0, 0, 0, 0}
+	want.Bool = false
+	want.BoolArray = [4]bool{false, false, false, false}
+	if b.N > 0 && !reflect.DeepEqual(ls, want) {
+		b.Fatalf("struct doesn't match:\ngot  %v;\nwant %v", ls, want)
+	}
+}
+
+func BenchmarkWriteFloats(b *testing.B) {
+	buf := new(bytes.Buffer)
+	var w io.Writer = buf
+	b.SetBytes(4 + 8)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		buf.Reset()
+		Write(w, BigEndian, s.Float32)
+		Write(w, BigEndian, s.Float64)
+	}
+	b.StopTimer()
+	if b.N > 0 && !bytes.Equal(buf.Bytes(), big[30:30+4+8]) {
+		b.Fatalf("first half doesn't match: %x %x", buf.Bytes(), big[30:30+4+8])
+	}
+}
+
+func BenchmarkReadSlice1000Float32s(b *testing.B) {
+	bsr := &byteSliceReader{}
+	slice := make([]float32, 1000)
+	buf := make([]byte, len(slice)*4)
+	b.SetBytes(int64(len(buf)))
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		bsr.remain = buf
+		Read(bsr, BigEndian, slice)
+	}
+}
+
+func BenchmarkWriteSlice1000Float32s(b *testing.B) {
+	slice := make([]float32, 1000)
+	buf := new(bytes.Buffer)
+	var w io.Writer = buf
+	b.SetBytes(4 * 1000)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		buf.Reset()
+		Write(w, BigEndian, slice)
+	}
+	b.StopTimer()
+}
diff --git a/libgo/go/encoding/csv/fuzz.go b/libgo/go/encoding/csv/fuzz.go
index dc33893..8be21d5 100644
--- a/libgo/go/encoding/csv/fuzz.go
+++ b/libgo/go/encoding/csv/fuzz.go
@@ -17,13 +17,13 @@ func Fuzz(data []byte) int {
 	buf := new(bytes.Buffer)
 
 	for _, tt := range []Reader{
-		Reader{},
-		Reader{Comma: ';'},
-		Reader{Comma: '\t'},
-		Reader{LazyQuotes: true},
-		Reader{TrimLeadingSpace: true},
-		Reader{Comment: '#'},
-		Reader{Comment: ';'},
+		{},
+		{Comma: ';'},
+		{Comma: '\t'},
+		{LazyQuotes: true},
+		{TrimLeadingSpace: true},
+		{Comment: '#'},
+		{Comment: ';'},
 	} {
 		r := NewReader(bytes.NewReader(data))
 		r.Comma = tt.Comma
diff --git a/libgo/go/encoding/gob/codec_test.go b/libgo/go/encoding/gob/codec_test.go
index 494abc9..f38e88b 100644
--- a/libgo/go/encoding/gob/codec_test.go
+++ b/libgo/go/encoding/gob/codec_test.go
@@ -591,7 +591,7 @@ func TestEndToEnd(t *testing.T) {
 		B:        18,
 		C:        -5,
 		M:        map[string]*float64{"pi": &pi, "e": &e},
-		M2:       map[int]T3{4: T3{X: pi, Z: &meaning}, 10: T3{X: e, Z: &fingers}},
+		M2:       map[int]T3{4: {X: pi, Z: &meaning}, 10: {X: e, Z: &fingers}},
 		Mstring:  map[string]string{"pi": "3.14", "e": "2.71"},
 		Mintptr:  map[int]*int{meaning: &fingers, fingers: &meaning},
 		Mcomp:    map[complex128]complex128{comp1: comp2, comp2: comp1},
diff --git a/libgo/go/encoding/gob/gobencdec_test.go b/libgo/go/encoding/gob/gobencdec_test.go
index 41a06b2..6d2c8db 100644
--- a/libgo/go/encoding/gob/gobencdec_test.go
+++ b/libgo/go/encoding/gob/gobencdec_test.go
@@ -707,7 +707,7 @@ func TestGobEncoderExtraIndirect(t *testing.T) {
 
 // Another bug: this caused a crash with the new Go1 Time type.
 // We throw in a gob-encoding array, to test another case of isZero,
-// and a struct containing an nil interface, to test a third.
+// and a struct containing a nil interface, to test a third.
 type isZeroBug struct {
 	T time.Time
 	S string
diff --git a/libgo/go/encoding/json/bench_test.go b/libgo/go/encoding/json/bench_test.go
index f2592e3..4a5fe7e 100644
--- a/libgo/go/encoding/json/bench_test.go
+++ b/libgo/go/encoding/json/bench_test.go
@@ -297,6 +297,22 @@ func BenchmarkIssue10335(b *testing.B) {
 	})
 }
 
+func BenchmarkIssue34127(b *testing.B) {
+	b.ReportAllocs()
+	j := struct {
+		Bar string `json:"bar,string"`
+	}{
+		Bar: `foobar`,
+	}
+	b.RunParallel(func(pb *testing.PB) {
+		for pb.Next() {
+			if _, err := Marshal(&j); err != nil {
+				b.Fatal(err)
+			}
+		}
+	})
+}
+
 func BenchmarkUnmapped(b *testing.B) {
 	b.ReportAllocs()
 	j := []byte(`{"s": "hello", "y": 2, "o": {"x": 0}, "a": [1, 99, {"x": 1}]}`)
@@ -373,3 +389,22 @@ func BenchmarkTypeFieldsCache(b *testing.B) {
 		})
 	}
 }
+
+func BenchmarkEncodeMarshaler(b *testing.B) {
+	b.ReportAllocs()
+
+	m := struct {
+		A int
+		B RawMessage
+	}{}
+
+	b.RunParallel(func(pb *testing.PB) {
+		enc := NewEncoder(ioutil.Discard)
+
+		for pb.Next() {
+			if err := enc.Encode(&m); err != nil {
+				b.Fatal("Encode:", err)
+			}
+		}
+	})
+}
diff --git a/libgo/go/encoding/json/decode.go b/libgo/go/encoding/json/decode.go
index cbd71ac..b434846 100644
--- a/libgo/go/encoding/json/decode.go
+++ b/libgo/go/encoding/json/decode.go
@@ -72,7 +72,8 @@ import (
 // use. If the map is nil, Unmarshal allocates a new map. Otherwise Unmarshal
 // reuses the existing map, keeping existing entries. Unmarshal then stores
 // key-value pairs from the JSON object into the map. The map's key type must
-// either be a string, an integer, or implement encoding.TextUnmarshaler.
+// either be any string type, an integer, implement json.Unmarshaler, or
+// implement encoding.TextUnmarshaler.
 //
 // If a JSON value is not appropriate for a given target type,
 // or if a JSON number overflows the target type, Unmarshal
@@ -199,66 +200,6 @@ func (n Number) Int64() (int64, error) {
 	return strconv.ParseInt(string(n), 10, 64)
 }
 
-// isValidNumber reports whether s is a valid JSON number literal.
-func isValidNumber(s string) bool {
-	// This function implements the JSON numbers grammar.
-	// See https://tools.ietf.org/html/rfc7159#section-6
-	// and https://json.org/number.gif
-
-	if s == "" {
-		return false
-	}
-
-	// Optional -
-	if s[0] == '-' {
-		s = s[1:]
-		if s == "" {
-			return false
-		}
-	}
-
-	// Digits
-	switch {
-	default:
-		return false
-
-	case s[0] == '0':
-		s = s[1:]
-
-	case '1' <= s[0] && s[0] <= '9':
-		s = s[1:]
-		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
-			s = s[1:]
-		}
-	}
-
-	// . followed by 1 or more digits.
-	if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' {
-		s = s[2:]
-		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
-			s = s[1:]
-		}
-	}
-
-	// e or E followed by an optional - or + and
-	// 1 or more digits.
-	if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') {
-		s = s[1:]
-		if s[0] == '+' || s[0] == '-' {
-			s = s[1:]
-			if s == "" {
-				return false
-			}
-		}
-		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
-			s = s[1:]
-		}
-	}
-
-	// Make sure we are at the end.
-	return s == ""
-}
-
 // decodeState represents the state while decoding a JSON value.
 type decodeState struct {
 	data         []byte
@@ -272,6 +213,9 @@ type decodeState struct {
 	savedError            error
 	useNumber             bool
 	disallowUnknownFields bool
+	// safeUnquote is the number of current string literal bytes that don't
+	// need to be unquoted. When negative, no bytes need unquoting.
+	safeUnquote int
 }
 
 // readIndex returns the position of the last byte read.
@@ -373,13 +317,27 @@ func (d *decodeState) rescanLiteral() {
 Switch:
 	switch data[i-1] {
 	case '"': // string
+		// safeUnquote is initialized at -1, which means that all bytes
+		// checked so far can be unquoted at a later time with no work
+		// at all. When reaching the closing '"', if safeUnquote is
+		// still -1, all bytes can be unquoted with no work. Otherwise,
+		// only those bytes up until the first '\\' or non-ascii rune
+		// can be safely unquoted.
+		safeUnquote := -1
 		for ; i < len(data); i++ {
-			switch data[i] {
-			case '\\':
+			if c := data[i]; c == '\\' {
+				if safeUnquote < 0 { // first unsafe byte
+					safeUnquote = int(i - d.off)
+				}
 				i++ // escaped char
-			case '"':
+			} else if c == '"' {
+				d.safeUnquote = safeUnquote
 				i++ // tokenize the closing quote too
 				break Switch
+			} else if c >= utf8.RuneSelf {
+				if safeUnquote < 0 { // first unsafe byte
+					safeUnquote = int(i - d.off)
+				}
 			}
 		}
 	case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '-': // number
@@ -475,8 +433,9 @@ func (d *decodeState) valueQuoted() interface{} {
 
 // indirect walks down v allocating pointers as needed,
 // until it gets to a non-pointer.
-// if it encounters an Unmarshaler, indirect stops and returns that.
-// if decodingNull is true, indirect stops at the last pointer so it can be set to nil.
+// If it encounters an Unmarshaler, indirect stops and returns that.
+// If decodingNull is true, indirect stops at the first settable pointer so it
+// can be set to nil.
 func indirect(v reflect.Value, decodingNull bool) (Unmarshaler, encoding.TextUnmarshaler, reflect.Value) {
 	// Issue #24153 indicates that it is generally not a guaranteed property
 	// that you may round-trip a reflect.Value by calling Value.Addr().Elem()
@@ -515,7 +474,7 @@ func indirect(v reflect.Value, decodingNull bool) (Unmarshaler, encoding.TextUnm
 			break
 		}
 
-		if v.Elem().Kind() != reflect.Ptr && decodingNull && v.CanSet() {
+		if decodingNull && v.CanSet() {
 			break
 		}
 
@@ -732,7 +691,7 @@ func (d *decodeState) object(v reflect.Value) error {
 		start := d.readIndex()
 		d.rescanLiteral()
 		item := d.data[start:d.readIndex()]
-		key, ok := unquoteBytes(item)
+		key, ok := d.unquoteBytes(item)
 		if !ok {
 			panic(phasePanicMsg)
 		}
@@ -831,14 +790,14 @@ func (d *decodeState) object(v reflect.Value) error {
 			kt := t.Key()
 			var kv reflect.Value
 			switch {
-			case kt.Kind() == reflect.String:
-				kv = reflect.ValueOf(key).Convert(kt)
 			case reflect.PtrTo(kt).Implements(textUnmarshalerType):
 				kv = reflect.New(kt)
 				if err := d.literalStore(item, kv, true); err != nil {
 					return err
 				}
 				kv = kv.Elem()
+			case kt.Kind() == reflect.String:
+				kv = reflect.ValueOf(key).Convert(kt)
 			default:
 				switch kt.Kind() {
 				case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
@@ -933,7 +892,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			d.saveError(&UnmarshalTypeError{Value: val, Type: v.Type(), Offset: int64(d.readIndex())})
 			return nil
 		}
-		s, ok := unquoteBytes(item)
+		s, ok := d.unquoteBytes(item)
 		if !ok {
 			if fromQuoted {
 				return fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type())
@@ -984,7 +943,7 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		}
 
 	case '"': // string
-		s, ok := unquoteBytes(item)
+		s, ok := d.unquoteBytes(item)
 		if !ok {
 			if fromQuoted {
 				return fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into %v", item, v.Type())
@@ -1007,6 +966,9 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 			}
 			v.SetBytes(b[:n])
 		case reflect.String:
+			if v.Type() == numberType && !isValidNumber(string(s)) {
+				return fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", item)
+			}
 			v.SetString(string(s))
 		case reflect.Interface:
 			if v.NumMethod() == 0 {
@@ -1027,10 +989,9 @@ func (d *decodeState) literalStore(item []byte, v reflect.Value, fromQuoted bool
 		switch v.Kind() {
 		default:
 			if v.Kind() == reflect.String && v.Type() == numberType {
+				// s must be a valid number, because it's
+				// already been tokenized.
 				v.SetString(s)
-				if !isValidNumber(s) {
-					return fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", item)
-				}
 				break
 			}
 			if fromQuoted {
@@ -1142,7 +1103,7 @@ func (d *decodeState) objectInterface() map[string]interface{} {
 		start := d.readIndex()
 		d.rescanLiteral()
 		item := d.data[start:d.readIndex()]
-		key, ok := unquote(item)
+		key, ok := d.unquote(item)
 		if !ok {
 			panic(phasePanicMsg)
 		}
@@ -1191,7 +1152,7 @@ func (d *decodeState) literalInterface() interface{} {
 		return c == 't'
 
 	case '"': // string
-		s, ok := unquote(item)
+		s, ok := d.unquote(item)
 		if !ok {
 			panic(phasePanicMsg)
 		}
@@ -1234,38 +1195,26 @@ func getu4(s []byte) rune {
 
 // unquote converts a quoted JSON string literal s into an actual string t.
 // The rules are different than for Go, so cannot use strconv.Unquote.
-func unquote(s []byte) (t string, ok bool) {
-	s, ok = unquoteBytes(s)
+// The first byte in s must be '"'.
+func (d *decodeState) unquote(s []byte) (t string, ok bool) {
+	s, ok = d.unquoteBytes(s)
 	t = string(s)
 	return
 }
 
-func unquoteBytes(s []byte) (t []byte, ok bool) {
-	if len(s) < 2 || s[0] != '"' || s[len(s)-1] != '"' {
+func (d *decodeState) unquoteBytes(s []byte) (t []byte, ok bool) {
+	// We already know that s[0] == '"'. However, we don't know that the
+	// closing quote exists in all cases, such as when the string is nested
+	// via the ",string" option.
+	if len(s) < 2 || s[len(s)-1] != '"' {
 		return
 	}
 	s = s[1 : len(s)-1]
 
-	// Check for unusual characters. If there are none,
-	// then no unquoting is needed, so return a slice of the
-	// original bytes.
-	r := 0
-	for r < len(s) {
-		c := s[r]
-		if c == '\\' || c == '"' || c < ' ' {
-			break
-		}
-		if c < utf8.RuneSelf {
-			r++
-			continue
-		}
-		rr, size := utf8.DecodeRune(s[r:])
-		if rr == utf8.RuneError && size == 1 {
-			break
-		}
-		r += size
-	}
-	if r == len(s) {
+	// If there are no unusual characters, no unquoting is needed, so return
+	// a slice of the original bytes.
+	r := d.safeUnquote
+	if r == -1 {
 		return s, true
 	}
 
diff --git a/libgo/go/encoding/json/decode_test.go b/libgo/go/encoding/json/decode_test.go
index 3f25893..498bd97 100644
--- a/libgo/go/encoding/json/decode_test.go
+++ b/libgo/go/encoding/json/decode_test.go
@@ -145,23 +145,15 @@ func (u8 *u8marshal) UnmarshalText(b []byte) error {
 var _ encoding.TextUnmarshaler = (*u8marshal)(nil)
 
 var (
-	um0, um1 unmarshaler // target2 of unmarshaling
-	ump      = &um1
 	umtrue   = unmarshaler{true}
 	umslice  = []unmarshaler{{true}}
-	umslicep = new([]unmarshaler)
 	umstruct = ustruct{unmarshaler{true}}
 
-	um0T, um1T   unmarshalerText // target2 of unmarshaling
-	umpType      = &um1T
-	umtrueXY     = unmarshalerText{"x", "y"}
-	umsliceXY    = []unmarshalerText{{"x", "y"}}
-	umslicepType = new([]unmarshalerText)
-	umstructType = new(ustructText)
-	umstructXY   = ustructText{unmarshalerText{"x", "y"}}
+	umtrueXY   = unmarshalerText{"x", "y"}
+	umsliceXY  = []unmarshalerText{{"x", "y"}}
+	umstructXY = ustructText{unmarshalerText{"x", "y"}}
 
-	ummapType = map[unmarshalerText]bool{}
-	ummapXY   = map[unmarshalerText]bool{{"x", "y"}: true}
+	ummapXY = map[unmarshalerText]bool{{"x", "y"}: true}
 )
 
 // Test data structures for anonymous fields.
@@ -279,9 +271,6 @@ type unexportedWithMethods struct{}
 
 func (unexportedWithMethods) F() {}
 
-func sliceAddr(x []int) *[]int                 { return &x }
-func mapAddr(x map[string]int) *map[string]int { return &x }
-
 type byteWithMarshalJSON byte
 
 func (b byteWithMarshalJSON) MarshalJSON() ([]byte, error) {
@@ -400,7 +389,7 @@ type mapStringToStringData struct {
 
 type unmarshalTest struct {
 	in                    string
-	ptr                   interface{}
+	ptr                   interface{} // new(type)
 	out                   interface{}
 	err                   error
 	useNumber             bool
@@ -412,6 +401,11 @@ type B struct {
 	B bool `json:",string"`
 }
 
+type DoublePtr struct {
+	I **int
+	J **int
+}
+
 var unmarshalTests = []unmarshalTest{
 	// basic types
 	{in: `true`, ptr: new(bool), out: true},
@@ -459,6 +453,7 @@ var unmarshalTests = []unmarshalTest{
 	{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},
 	{in: `[2, 3`, err: &SyntaxError{msg: "unexpected end of JSON input", Offset: 5}},
+	{in: `{"F3": -}`, ptr: new(V), out: V{F3: Number("-")}, err: &SyntaxError{msg: "invalid character '}' in numeric literal", Offset: 9}},
 
 	// raw value errors
 	{in: "\x01 42", err: &SyntaxError{"invalid character '\\x01' looking for beginning of value", 1}},
@@ -493,18 +488,18 @@ var unmarshalTests = []unmarshalTest{
 	{in: pallValueCompact, ptr: new(*All), out: &pallValue},
 
 	// unmarshal interface test
-	{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":"x:y"}}`, ptr: &umstruct, out: umstruct},
+	{in: `{"T":false}`, ptr: new(unmarshaler), out: umtrue}, // use "false" so test will fail if custom unmarshaler is not called
+	{in: `{"T":false}`, ptr: new(*unmarshaler), out: &umtrue},
+	{in: `[{"T":false}]`, ptr: new([]unmarshaler), out: umslice},
+	{in: `[{"T":false}]`, ptr: new(*[]unmarshaler), out: &umslice},
+	{in: `{"M":{"T":"x:y"}}`, ptr: new(ustruct), out: umstruct},
 
 	// UnmarshalText interface test
-	{in: `"x:y"`, ptr: &um0T, out: umtrueXY},
-	{in: `"x:y"`, ptr: &umpType, out: &umtrueXY},
-	{in: `["x:y"]`, ptr: &umsliceXY, out: umsliceXY},
-	{in: `["x:y"]`, ptr: &umslicepType, out: &umsliceXY},
-	{in: `{"M":"x:y"}`, ptr: umstructType, out: umstructXY},
+	{in: `"x:y"`, ptr: new(unmarshalerText), out: umtrueXY},
+	{in: `"x:y"`, ptr: new(*unmarshalerText), out: &umtrueXY},
+	{in: `["x:y"]`, ptr: new([]unmarshalerText), out: umsliceXY},
+	{in: `["x:y"]`, ptr: new(*[]unmarshalerText), out: &umsliceXY},
+	{in: `{"M":"x:y"}`, ptr: new(ustructText), out: umstructXY},
 
 	// integer-keyed map test
 	{
@@ -579,15 +574,9 @@ var unmarshalTests = []unmarshalTest{
 	},
 
 	// Map keys can be encoding.TextUnmarshalers.
-	{in: `{"x:y":true}`, ptr: &ummapType, out: ummapXY},
+	{in: `{"x:y":true}`, ptr: new(map[unmarshalerText]bool), out: ummapXY},
 	// If multiple values for the same key exists, only the most recent value is used.
-	{in: `{"x:y":false,"x:y":true}`, ptr: &ummapType, out: ummapXY},
-
-	// Overwriting of data.
-	// This is different from package xml, but it's what we've always done.
-	// Now documented and tested.
-	{in: `[2]`, ptr: sliceAddr([]int{1}), out: []int{2}},
-	{in: `{"key": 2}`, ptr: mapAddr(map[string]int{"old": 0, "key": 1}), out: map[string]int{"key": 2}},
+	{in: `{"x:y":false,"x:y":true}`, ptr: new(map[unmarshalerText]bool), out: ummapXY},
 
 	{
 		in: `{
@@ -672,6 +661,11 @@ var unmarshalTests = []unmarshalTest{
 		err:                   fmt.Errorf("json: unknown field \"X\""),
 		disallowUnknownFields: true,
 	},
+	{
+		in:  `{"I": 0, "I": null, "J": null}`,
+		ptr: new(DoublePtr),
+		out: DoublePtr{I: nil, J: nil},
+	},
 
 	// invalid UTF-8 is coerced to valid UTF-8.
 	{
@@ -713,19 +707,19 @@ var unmarshalTests = []unmarshalTest{
 	// Used to be issue 8305, but time.Time implements encoding.TextUnmarshaler so this works now.
 	{
 		in:  `{"2009-11-10T23:00:00Z": "hello world"}`,
-		ptr: &map[time.Time]string{},
+		ptr: new(map[time.Time]string),
 		out: map[time.Time]string{time.Date(2009, 11, 10, 23, 0, 0, 0, time.UTC): "hello world"},
 	},
 
 	// issue 8305
 	{
 		in:  `{"2009-11-10T23:00:00Z": "hello world"}`,
-		ptr: &map[Point]string{},
+		ptr: new(map[Point]string),
 		err: &UnmarshalTypeError{Value: "object", Type: reflect.TypeOf(map[Point]string{}), Offset: 1},
 	},
 	{
 		in:  `{"asdf": "hello world"}`,
-		ptr: &map[unmarshaler]string{},
+		ptr: new(map[unmarshaler]string),
 		err: &UnmarshalTypeError{Value: "object", Type: reflect.TypeOf(map[unmarshaler]string{}), Offset: 1},
 	},
 
@@ -955,6 +949,37 @@ var unmarshalTests = []unmarshalTest{
 			Offset: 29,
 		},
 	},
+	// #14702
+	{
+		in:  `invalid`,
+		ptr: new(Number),
+		err: &SyntaxError{
+			msg:    "invalid character 'i' looking for beginning of value",
+			Offset: 1,
+		},
+	},
+	{
+		in:  `"invalid"`,
+		ptr: new(Number),
+		err: fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", `"invalid"`),
+	},
+	{
+		in:  `{"A":"invalid"}`,
+		ptr: new(struct{ A Number }),
+		err: fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", `"invalid"`),
+	},
+	{
+		in: `{"A":"invalid"}`,
+		ptr: new(struct {
+			A Number `json:",string"`
+		}),
+		err: fmt.Errorf("json: invalid use of ,string struct tag, trying to unmarshal %q into json.Number", `invalid`),
+	},
+	{
+		in:  `{"A":"invalid"}`,
+		ptr: new(map[string]Number),
+		err: fmt.Errorf("json: invalid number literal, trying to unmarshal %q into Number", `"invalid"`),
+	},
 }
 
 func TestMarshal(t *testing.T) {
@@ -1077,8 +1102,27 @@ func TestUnmarshal(t *testing.T) {
 			continue
 		}
 
+		typ := reflect.TypeOf(tt.ptr)
+		if typ.Kind() != reflect.Ptr {
+			t.Errorf("#%d: unmarshalTest.ptr %T is not a pointer type", i, tt.ptr)
+			continue
+		}
+		typ = typ.Elem()
+
 		// v = new(right-type)
-		v := reflect.New(reflect.TypeOf(tt.ptr).Elem())
+		v := reflect.New(typ)
+
+		if !reflect.DeepEqual(tt.ptr, v.Interface()) {
+			// There's no reason for ptr to point to non-zero data,
+			// as we decode into new(right-type), so the data is
+			// discarded.
+			// This can easily mean tests that silently don't test
+			// what they should. To test decoding into existing
+			// data, see TestPrefilled.
+			t.Errorf("#%d: unmarshalTest.ptr %#v is not a pointer to a zero value", i, tt.ptr)
+			continue
+		}
+
 		dec := NewDecoder(bytes.NewReader(in))
 		if tt.useNumber {
 			dec.UseNumber()
@@ -1741,41 +1785,6 @@ type NullTest struct {
 	Struct struct{}
 }
 
-type NullTestStrings struct {
-	Bool      bool              `json:",string"`
-	Int       int               `json:",string"`
-	Int8      int8              `json:",string"`
-	Int16     int16             `json:",string"`
-	Int32     int32             `json:",string"`
-	Int64     int64             `json:",string"`
-	Uint      uint              `json:",string"`
-	Uint8     uint8             `json:",string"`
-	Uint16    uint16            `json:",string"`
-	Uint32    uint32            `json:",string"`
-	Uint64    uint64            `json:",string"`
-	Float32   float32           `json:",string"`
-	Float64   float64           `json:",string"`
-	String    string            `json:",string"`
-	PBool     *bool             `json:",string"`
-	Map       map[string]string `json:",string"`
-	Slice     []string          `json:",string"`
-	Interface interface{}       `json:",string"`
-
-	PRaw    *RawMessage           `json:",string"`
-	PTime   *time.Time            `json:",string"`
-	PBigInt *big.Int              `json:",string"`
-	PText   *MustNotUnmarshalText `json:",string"`
-	PBuffer *bytes.Buffer         `json:",string"`
-	PStruct *struct{}             `json:",string"`
-
-	Raw    RawMessage           `json:",string"`
-	Time   time.Time            `json:",string"`
-	BigInt big.Int              `json:",string"`
-	Text   MustNotUnmarshalText `json:",string"`
-	Buffer bytes.Buffer         `json:",string"`
-	Struct struct{}             `json:",string"`
-}
-
 // JSON null values should be ignored for primitives and string values instead of resulting in an error.
 // Issue 2540
 func TestUnmarshalNulls(t *testing.T) {
@@ -2086,11 +2095,10 @@ func TestSkipArrayObjects(t *testing.T) {
 	}
 }
 
-// Test semantics of pre-filled struct fields and pre-filled map fields.
-// Issue 4900.
+// Test semantics of pre-filled data, such as struct fields, map elements,
+// slices, and arrays.
+// Issues 4900 and 8837, among others.
 func TestPrefilled(t *testing.T) {
-	ptrToMap := func(m map[string]interface{}) *map[string]interface{} { return &m }
-
 	// Values here change, cannot reuse table across runs.
 	var prefillTests = []struct {
 		in  string
@@ -2104,8 +2112,28 @@ func TestPrefilled(t *testing.T) {
 		},
 		{
 			in:  `{"X": 1, "Y": 2}`,
-			ptr: ptrToMap(map[string]interface{}{"X": float32(3), "Y": int16(4), "Z": 1.5}),
-			out: ptrToMap(map[string]interface{}{"X": float64(1), "Y": float64(2), "Z": 1.5}),
+			ptr: &map[string]interface{}{"X": float32(3), "Y": int16(4), "Z": 1.5},
+			out: &map[string]interface{}{"X": float64(1), "Y": float64(2), "Z": 1.5},
+		},
+		{
+			in:  `[2]`,
+			ptr: &[]int{1},
+			out: &[]int{2},
+		},
+		{
+			in:  `[2, 3]`,
+			ptr: &[]int{1},
+			out: &[]int{2, 3},
+		},
+		{
+			in:  `[2, 3]`,
+			ptr: &[...]int{1},
+			out: &[...]int{2},
+		},
+		{
+			in:  `[3]`,
+			ptr: &[...]int{1, 2},
+			out: &[...]int{3, 0},
 		},
 	}
 
@@ -2323,6 +2351,41 @@ func TestUnmarshalEmbeddedUnexported(t *testing.T) {
 	}
 }
 
+func TestUnmarshalErrorAfterMultipleJSON(t *testing.T) {
+	tests := []struct {
+		in  string
+		err error
+	}{{
+		in:  `1 false null :`,
+		err: &SyntaxError{"invalid character ':' looking for beginning of value", 14},
+	}, {
+		in:  `1 [] [,]`,
+		err: &SyntaxError{"invalid character ',' looking for beginning of value", 7},
+	}, {
+		in:  `1 [] [true:]`,
+		err: &SyntaxError{"invalid character ':' after array element", 11},
+	}, {
+		in:  `1  {}    {"x"=}`,
+		err: &SyntaxError{"invalid character '=' after object key", 14},
+	}, {
+		in:  `falsetruenul#`,
+		err: &SyntaxError{"invalid character '#' in literal null (expecting 'l')", 13},
+	}}
+	for i, tt := range tests {
+		dec := NewDecoder(strings.NewReader(tt.in))
+		var err error
+		for {
+			var v interface{}
+			if err = dec.Decode(&v); err != nil {
+				break
+			}
+		}
+		if !reflect.DeepEqual(err, tt.err) {
+			t.Errorf("#%d: got %#v, want %#v", i, err, tt.err)
+		}
+	}
+}
+
 type unmarshalPanic struct{}
 
 func (unmarshalPanic) UnmarshalJSON([]byte) error { panic(0xdead) }
@@ -2348,3 +2411,23 @@ func TestUnmarshalRecursivePointer(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+type textUnmarshalerString string
+
+func (m *textUnmarshalerString) UnmarshalText(text []byte) error {
+	*m = textUnmarshalerString(strings.ToLower(string(text)))
+	return nil
+}
+
+// Test unmarshal to a map, with map key is a user defined type.
+// See golang.org/issues/34437.
+func TestUnmarshalMapWithTextUnmarshalerStringKey(t *testing.T) {
+	var p map[textUnmarshalerString]string
+	if err := Unmarshal([]byte(`{"FOO": "1"}`), &p); err != nil {
+		t.Fatalf("Unmarshal unexpected error: %v", err)
+	}
+
+	if _, ok := p["foo"]; !ok {
+		t.Errorf(`Key "foo" is not existed in map: %v`, p)
+	}
+}
diff --git a/libgo/go/encoding/json/encode.go b/libgo/go/encoding/json/encode.go
index 6741276..39cdaeb 100644
--- a/libgo/go/encoding/json/encode.go
+++ b/libgo/go/encoding/json/encode.go
@@ -153,7 +153,7 @@ import (
 //
 // JSON cannot represent cyclic data structures and Marshal does not
 // handle them. Passing cyclic structures to Marshal will result in
-// an infinite recursion.
+// an error.
 //
 func Marshal(v interface{}) ([]byte, error) {
 	e := newEncodeState()
@@ -164,7 +164,6 @@ func Marshal(v interface{}) ([]byte, error) {
 	}
 	buf := append([]byte(nil), e.Bytes()...)
 
-	e.Reset()
 	encodeStatePool.Put(e)
 
 	return buf, nil
@@ -262,14 +261,22 @@ func (e *InvalidUTF8Error) Error() string {
 
 // A MarshalerError represents an error from calling a MarshalJSON or MarshalText method.
 type MarshalerError struct {
-	Type reflect.Type
-	Err  error
+	Type       reflect.Type
+	Err        error
+	sourceFunc string
 }
 
 func (e *MarshalerError) Error() string {
-	return "json: error calling MarshalJSON for type " + e.Type.String() + ": " + e.Err.Error()
+	srcFunc := e.sourceFunc
+	if srcFunc == "" {
+		srcFunc = "MarshalJSON"
+	}
+	return "json: error calling " + srcFunc +
+		" for type " + e.Type.String() +
+		": " + e.Err.Error()
 }
 
+// Unwrap returns the underlying error.
 func (e *MarshalerError) Unwrap() error { return e.Err }
 
 var hex = "0123456789abcdef"
@@ -278,17 +285,31 @@ var hex = "0123456789abcdef"
 type encodeState struct {
 	bytes.Buffer // accumulated output
 	scratch      [64]byte
+
+	// Keep track of what pointers we've seen in the current recursive call
+	// path, to avoid cycles that could lead to a stack overflow. Only do
+	// the relatively expensive map operations if ptrLevel is larger than
+	// startDetectingCyclesAfter, so that we skip the work if we're within a
+	// reasonable amount of nested pointers deep.
+	ptrLevel uint
+	ptrSeen  map[interface{}]struct{}
 }
 
+const startDetectingCyclesAfter = 1000
+
 var encodeStatePool sync.Pool
 
 func newEncodeState() *encodeState {
 	if v := encodeStatePool.Get(); v != nil {
 		e := v.(*encodeState)
 		e.Reset()
+		if len(e.ptrSeen) > 0 {
+			panic("ptrEncoder.encode should have emptied ptrSeen via defers")
+		}
+		e.ptrLevel = 0
 		return e
 	}
-	return new(encodeState)
+	return &encodeState{ptrSeen: make(map[interface{}]struct{})}
 }
 
 // jsonError is an error wrapper type for internal use only.
@@ -392,19 +413,22 @@ var (
 // newTypeEncoder constructs an encoderFunc for a type.
 // The returned encoder only checks CanAddr when allowAddr is true.
 func newTypeEncoder(t reflect.Type, allowAddr bool) encoderFunc {
-	if t.Implements(marshalerType) {
-		return marshalerEncoder
-	}
+	// If we have a non-pointer value whose type implements
+	// Marshaler with a value receiver, then we're better off taking
+	// the address of the value - otherwise we end up with an
+	// allocation as we cast the value to an interface.
 	if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(marshalerType) {
 		return newCondAddrEncoder(addrMarshalerEncoder, newTypeEncoder(t, false))
 	}
-
-	if t.Implements(textMarshalerType) {
-		return textMarshalerEncoder
+	if t.Implements(marshalerType) {
+		return marshalerEncoder
 	}
 	if t.Kind() != reflect.Ptr && allowAddr && reflect.PtrTo(t).Implements(textMarshalerType) {
 		return newCondAddrEncoder(addrTextMarshalerEncoder, newTypeEncoder(t, false))
 	}
+	if t.Implements(textMarshalerType) {
+		return textMarshalerEncoder
+	}
 
 	switch t.Kind() {
 	case reflect.Bool:
@@ -456,7 +480,7 @@ func marshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
 		err = compact(&e.Buffer, b, opts.escapeHTML)
 	}
 	if err != nil {
-		e.error(&MarshalerError{v.Type(), err})
+		e.error(&MarshalerError{v.Type(), err, "MarshalJSON"})
 	}
 }
 
@@ -473,7 +497,7 @@ func addrMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
 		err = compact(&e.Buffer, b, opts.escapeHTML)
 	}
 	if err != nil {
-		e.error(&MarshalerError{v.Type(), err})
+		e.error(&MarshalerError{v.Type(), err, "MarshalJSON"})
 	}
 }
 
@@ -482,10 +506,14 @@ func textMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
 		e.WriteString("null")
 		return
 	}
-	m := v.Interface().(encoding.TextMarshaler)
+	m, ok := v.Interface().(encoding.TextMarshaler)
+	if !ok {
+		e.WriteString("null")
+		return
+	}
 	b, err := m.MarshalText()
 	if err != nil {
-		e.error(&MarshalerError{v.Type(), err})
+		e.error(&MarshalerError{v.Type(), err, "MarshalText"})
 	}
 	e.stringBytes(b, opts.escapeHTML)
 }
@@ -499,7 +527,7 @@ func addrTextMarshalerEncoder(e *encodeState, v reflect.Value, opts encOpts) {
 	m := va.Interface().(encoding.TextMarshaler)
 	b, err := m.MarshalText()
 	if err != nil {
-		e.error(&MarshalerError{v.Type(), err})
+		e.error(&MarshalerError{v.Type(), err, "MarshalText"})
 	}
 	e.stringBytes(b, opts.escapeHTML)
 }
@@ -597,20 +625,86 @@ func stringEncoder(e *encodeState, v reflect.Value, opts encOpts) {
 		if !isValidNumber(numStr) {
 			e.error(fmt.Errorf("json: invalid number literal %q", numStr))
 		}
+		if opts.quoted {
+			e.WriteByte('"')
+		}
 		e.WriteString(numStr)
+		if opts.quoted {
+			e.WriteByte('"')
+		}
 		return
 	}
 	if opts.quoted {
-		sb, err := Marshal(v.String())
-		if err != nil {
-			e.error(err)
-		}
-		e.string(string(sb), opts.escapeHTML)
+		b := make([]byte, 0, v.Len()+2)
+		b = append(b, '"')
+		b = append(b, []byte(v.String())...)
+		b = append(b, '"')
+		e.stringBytes(b, opts.escapeHTML)
 	} else {
 		e.string(v.String(), opts.escapeHTML)
 	}
 }
 
+// isValidNumber reports whether s is a valid JSON number literal.
+func isValidNumber(s string) bool {
+	// This function implements the JSON numbers grammar.
+	// See https://tools.ietf.org/html/rfc7159#section-6
+	// and https://json.org/number.gif
+
+	if s == "" {
+		return false
+	}
+
+	// Optional -
+	if s[0] == '-' {
+		s = s[1:]
+		if s == "" {
+			return false
+		}
+	}
+
+	// Digits
+	switch {
+	default:
+		return false
+
+	case s[0] == '0':
+		s = s[1:]
+
+	case '1' <= s[0] && s[0] <= '9':
+		s = s[1:]
+		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+			s = s[1:]
+		}
+	}
+
+	// . followed by 1 or more digits.
+	if len(s) >= 2 && s[0] == '.' && '0' <= s[1] && s[1] <= '9' {
+		s = s[2:]
+		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+			s = s[1:]
+		}
+	}
+
+	// e or E followed by an optional - or + and
+	// 1 or more digits.
+	if len(s) >= 2 && (s[0] == 'e' || s[0] == 'E') {
+		s = s[1:]
+		if s[0] == '+' || s[0] == '-' {
+			s = s[1:]
+			if s == "" {
+				return false
+			}
+		}
+		for len(s) > 0 && '0' <= s[0] && s[0] <= '9' {
+			s = s[1:]
+		}
+	}
+
+	// Make sure we are at the end.
+	return s == ""
+}
+
 func interfaceEncoder(e *encodeState, v reflect.Value, opts encOpts) {
 	if v.IsNil() {
 		e.WriteString("null")
@@ -692,7 +786,7 @@ func (me mapEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
 	for i, v := range keys {
 		sv[i].v = v
 		if err := sv[i].resolve(); err != nil {
-			e.error(&MarshalerError{v.Type(), err})
+			e.error(fmt.Errorf("json: encoding error for type %q: %q", v.Type().String(), err.Error()))
 		}
 	}
 	sort.Slice(sv, func(i, j int) bool { return sv[i].s < sv[j].s })
@@ -807,7 +901,18 @@ func (pe ptrEncoder) encode(e *encodeState, v reflect.Value, opts encOpts) {
 		e.WriteString("null")
 		return
 	}
+	if e.ptrLevel++; e.ptrLevel > startDetectingCyclesAfter {
+		// We're a large number of nested ptrEncoder.encode calls deep;
+		// start checking if we've run into a pointer cycle.
+		ptr := v.Interface()
+		if _, ok := e.ptrSeen[ptr]; ok {
+			e.error(&UnsupportedValueError{v, fmt.Sprintf("encountered a cycle via %s", v.Type())})
+		}
+		e.ptrSeen[ptr] = struct{}{}
+		defer delete(e.ptrSeen, ptr)
+	}
 	pe.elemEnc(e, v.Elem(), opts)
+	e.ptrLevel--
 }
 
 func newPtrEncoder(t reflect.Type) encoderFunc {
@@ -872,6 +977,9 @@ func (w *reflectWithString) resolve() error {
 		return nil
 	}
 	if tm, ok := w.v.Interface().(encoding.TextMarshaler); ok {
+		if w.v.Kind() == reflect.Ptr && w.v.IsNil() {
+			return nil
+		}
 		buf, err := tm.MarshalText()
 		w.s = string(buf)
 		return err
diff --git a/libgo/go/encoding/json/encode_test.go b/libgo/go/encoding/json/encode_test.go
index bdf2a9f..5110c7d 100644
--- a/libgo/go/encoding/json/encode_test.go
+++ b/libgo/go/encoding/json/encode_test.go
@@ -6,6 +6,7 @@ package json
 
 import (
 	"bytes"
+	"encoding"
 	"fmt"
 	"log"
 	"math"
@@ -75,13 +76,15 @@ type StringTag struct {
 	IntStr     int64   `json:",string"`
 	UintptrStr uintptr `json:",string"`
 	StrStr     string  `json:",string"`
+	NumberStr  Number  `json:",string"`
 }
 
 var stringTagExpected = `{
  "BoolStr": "true",
  "IntStr": "42",
  "UintptrStr": "44",
- "StrStr": "\"xzbit\""
+ "StrStr": "\"xzbit\"",
+ "NumberStr": "46"
 }`
 
 func TestStringTag(t *testing.T) {
@@ -90,6 +93,7 @@ func TestStringTag(t *testing.T) {
 	s.IntStr = 42
 	s.UintptrStr = 44
 	s.StrStr = "xzbit"
+	s.NumberStr = "46"
 	got, err := MarshalIndent(&s, "", " ")
 	if err != nil {
 		t.Fatal(err)
@@ -134,10 +138,45 @@ func TestEncodeRenamedByteSlice(t *testing.T) {
 	}
 }
 
+type SamePointerNoCycle struct {
+	Ptr1, Ptr2 *SamePointerNoCycle
+}
+
+var samePointerNoCycle = &SamePointerNoCycle{}
+
+type PointerCycle struct {
+	Ptr *PointerCycle
+}
+
+var pointerCycle = &PointerCycle{}
+
+type PointerCycleIndirect struct {
+	Ptrs []interface{}
+}
+
+var pointerCycleIndirect = &PointerCycleIndirect{}
+
+func init() {
+	ptr := &SamePointerNoCycle{}
+	samePointerNoCycle.Ptr1 = ptr
+	samePointerNoCycle.Ptr2 = ptr
+
+	pointerCycle.Ptr = pointerCycle
+	pointerCycleIndirect.Ptrs = []interface{}{pointerCycleIndirect}
+}
+
+func TestSamePointerNoCycle(t *testing.T) {
+	if _, err := Marshal(samePointerNoCycle); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
 var unsupportedValues = []interface{}{
 	math.NaN(),
 	math.Inf(-1),
 	math.Inf(1),
+	pointerCycle,
+	pointerCycleIndirect,
 }
 
 func TestUnsupportedValues(t *testing.T) {
@@ -453,18 +492,31 @@ type BugX struct {
 	BugB
 }
 
-// Issue 16042. Even if a nil interface value is passed in
-// as long as it implements MarshalJSON, it should be marshaled.
-type nilMarshaler string
+// golang.org/issue/16042.
+// Even if a nil interface value is passed in, as long as
+// it implements Marshaler, it should be marshaled.
+type nilJSONMarshaler string
 
-func (nm *nilMarshaler) MarshalJSON() ([]byte, error) {
+func (nm *nilJSONMarshaler) MarshalJSON() ([]byte, error) {
 	if nm == nil {
 		return Marshal("0zenil0")
 	}
 	return Marshal("zenil:" + string(*nm))
 }
 
-// Issue 16042.
+// golang.org/issue/34235.
+// Even if a nil interface value is passed in, as long as
+// it implements encoding.TextMarshaler, it should be marshaled.
+type nilTextMarshaler string
+
+func (nm *nilTextMarshaler) MarshalText() ([]byte, error) {
+	if nm == nil {
+		return []byte("0zenil0"), nil
+	}
+	return []byte("zenil:" + string(*nm)), nil
+}
+
+// See golang.org/issue/16042 and golang.org/issue/34235.
 func TestNilMarshal(t *testing.T) {
 	testCases := []struct {
 		v    interface{}
@@ -478,8 +530,11 @@ func TestNilMarshal(t *testing.T) {
 		{v: []byte(nil), want: `null`},
 		{v: struct{ M string }{"gopher"}, want: `{"M":"gopher"}`},
 		{v: struct{ M Marshaler }{}, want: `{"M":null}`},
-		{v: struct{ M Marshaler }{(*nilMarshaler)(nil)}, want: `{"M":"0zenil0"}`},
-		{v: struct{ M interface{} }{(*nilMarshaler)(nil)}, want: `{"M":null}`},
+		{v: struct{ M Marshaler }{(*nilJSONMarshaler)(nil)}, want: `{"M":"0zenil0"}`},
+		{v: struct{ M interface{} }{(*nilJSONMarshaler)(nil)}, want: `{"M":null}`},
+		{v: struct{ M encoding.TextMarshaler }{}, want: `{"M":null}`},
+		{v: struct{ M encoding.TextMarshaler }{(*nilTextMarshaler)(nil)}, want: `{"M":"0zenil0"}`},
+		{v: struct{ M interface{} }{(*nilTextMarshaler)(nil)}, want: `{"M":null}`},
 	}
 
 	for _, tt := range testCases {
@@ -793,6 +848,21 @@ func TestTextMarshalerMapKeysAreSorted(t *testing.T) {
 	}
 }
 
+// https://golang.org/issue/33675
+func TestNilMarshalerTextMapKey(t *testing.T) {
+	b, err := Marshal(map[*unmarshalerText]int{
+		(*unmarshalerText)(nil): 1,
+		{"A", "B"}:              2,
+	})
+	if err != nil {
+		t.Fatalf("Failed to Marshal *text.Marshaler: %v", err)
+	}
+	const want = `{"":1,"A:B":2}`
+	if string(b) != want {
+		t.Errorf("Marshal map with *text.Marshaler keys: got %#q, want %#q", b, want)
+	}
+}
+
 var re = regexp.MustCompile
 
 // syntactic checks on form of marshaled floating point numbers.
@@ -1029,3 +1099,30 @@ func TestMarshalUncommonFieldNames(t *testing.T) {
 		t.Fatalf("Marshal: got %s want %s", got, want)
 	}
 }
+
+func TestMarshalerError(t *testing.T) {
+	s := "test variable"
+	st := reflect.TypeOf(s)
+	errText := "json: test error"
+
+	tests := []struct {
+		err  *MarshalerError
+		want string
+	}{
+		{
+			&MarshalerError{st, fmt.Errorf(errText), ""},
+			"json: error calling MarshalJSON for type " + st.String() + ": " + errText,
+		},
+		{
+			&MarshalerError{st, fmt.Errorf(errText), "TestMarshalerError"},
+			"json: error calling TestMarshalerError for type " + st.String() + ": " + errText,
+		},
+	}
+
+	for i, tt := range tests {
+		got := tt.err.Error()
+		if got != tt.want {
+			t.Errorf("MarshalerError test %d, got: %s, want: %s", i, got, tt.want)
+		}
+	}
+}
diff --git a/libgo/go/encoding/json/indent.go b/libgo/go/encoding/json/indent.go
index fba1954..2924d3b 100644
--- a/libgo/go/encoding/json/indent.go
+++ b/libgo/go/encoding/json/indent.go
@@ -4,7 +4,9 @@
 
 package json
 
-import "bytes"
+import (
+	"bytes"
+)
 
 // Compact appends to dst the JSON-encoded src with
 // insignificant space characters elided.
@@ -14,8 +16,8 @@ func Compact(dst *bytes.Buffer, src []byte) error {
 
 func compact(dst *bytes.Buffer, src []byte, escape bool) error {
 	origLen := dst.Len()
-	var scan scanner
-	scan.reset()
+	scan := newScanner()
+	defer freeScanner(scan)
 	start := 0
 	for i, c := range src {
 		if escape && (c == '<' || c == '>' || c == '&') {
@@ -28,7 +30,7 @@ func compact(dst *bytes.Buffer, src []byte, escape bool) error {
 			start = i + 1
 		}
 		// Convert U+2028 and U+2029 (E2 80 A8 and E2 80 A9).
-		if c == 0xE2 && i+2 < len(src) && src[i+1] == 0x80 && src[i+2]&^1 == 0xA8 {
+		if escape && c == 0xE2 && i+2 < len(src) && src[i+1] == 0x80 && src[i+2]&^1 == 0xA8 {
 			if start < i {
 				dst.Write(src[start:i])
 			}
@@ -36,7 +38,7 @@ func compact(dst *bytes.Buffer, src []byte, escape bool) error {
 			dst.WriteByte(hex[src[i+2]&0xF])
 			start = i + 3
 		}
-		v := scan.step(&scan, c)
+		v := scan.step(scan, c)
 		if v >= scanSkipSpace {
 			if v == scanError {
 				break
@@ -78,13 +80,13 @@ func newline(dst *bytes.Buffer, prefix, indent string, depth int) {
 // if src ends in a trailing newline, so will dst.
 func Indent(dst *bytes.Buffer, src []byte, prefix, indent string) error {
 	origLen := dst.Len()
-	var scan scanner
-	scan.reset()
+	scan := newScanner()
+	defer freeScanner(scan)
 	needIndent := false
 	depth := 0
 	for _, c := range src {
 		scan.bytes++
-		v := scan.step(&scan, c)
+		v := scan.step(scan, c)
 		if v == scanSkipSpace {
 			continue
 		}
diff --git a/libgo/go/encoding/json/scanner.go b/libgo/go/encoding/json/scanner.go
index 8857224..552bd70 100644
--- a/libgo/go/encoding/json/scanner.go
+++ b/libgo/go/encoding/json/scanner.go
@@ -13,11 +13,16 @@ package json
 // This file starts with two simple examples using the scanner
 // before diving into the scanner itself.
 
-import "strconv"
+import (
+	"strconv"
+	"sync"
+)
 
 // Valid reports whether data is a valid JSON encoding.
 func Valid(data []byte) bool {
-	return checkValid(data, &scanner{}) == nil
+	scan := newScanner()
+	defer freeScanner(scan)
+	return checkValid(data, scan) == nil
 }
 
 // checkValid verifies that data is valid JSON-encoded data.
@@ -45,7 +50,7 @@ type SyntaxError struct {
 func (e *SyntaxError) Error() string { return e.msg }
 
 // A scanner is a JSON scanning state machine.
-// Callers call scan.reset() and then pass bytes in one at a time
+// Callers call scan.reset and then pass bytes in one at a time
 // by calling scan.step(&scan, c) for each byte.
 // The return value, referred to as an opcode, tells the
 // caller about significant parsing events like beginning
@@ -72,10 +77,33 @@ type scanner struct {
 	// Error that happened, if any.
 	err error
 
-	// total bytes consumed, updated by decoder.Decode
+	// total bytes consumed, updated by decoder.Decode (and deliberately
+	// not set to zero by scan.reset)
 	bytes int64
 }
 
+var scannerPool = sync.Pool{
+	New: func() interface{} {
+		return &scanner{}
+	},
+}
+
+func newScanner() *scanner {
+	scan := scannerPool.Get().(*scanner)
+	// scan.reset by design doesn't set bytes to zero
+	scan.bytes = 0
+	scan.reset()
+	return scan
+}
+
+func freeScanner(scan *scanner) {
+	// Avoid hanging on to too much memory in extreme cases.
+	if len(scan.parseState) > 1024 {
+		scan.parseState = nil
+	}
+	scannerPool.Put(scan)
+}
+
 // These values are returned by the state transition functions
 // assigned to scanner.state and the method scanner.eof.
 // They give details about the current state of the scan that
diff --git a/libgo/go/encoding/json/scanner_test.go b/libgo/go/encoding/json/scanner_test.go
index 6cdbe7d..3737516 100644
--- a/libgo/go/encoding/json/scanner_test.go
+++ b/libgo/go/encoding/json/scanner_test.go
@@ -48,6 +48,7 @@ var examples = []example{
 	{`[1,2,3]`, "[\n\t1,\n\t2,\n\t3\n]"},
 	{`{"x":1}`, "{\n\t\"x\": 1\n}"},
 	{ex1, ex1i},
+	{"{\"\":\"<>&\u2028\u2029\"}", "{\n\t\"\": \"<>&\u2028\u2029\"\n}"}, // See golang.org/issue/34070
 }
 
 var ex1 = `[true,false,null,"x",1,1.5,0,-5e+2]`
@@ -89,8 +90,8 @@ func TestCompactSeparators(t *testing.T) {
 	tests := []struct {
 		in, compact string
 	}{
-		{"{\"\u2028\": 1}", `{"\u2028":1}`},
-		{"{\"\u2029\" :2}", `{"\u2029":2}`},
+		{"{\"\u2028\": 1}", "{\"\u2028\":1}"},
+		{"{\"\u2029\" :2}", "{\"\u2029\":2}"},
 	}
 	for _, tt := range tests {
 		var buf bytes.Buffer
diff --git a/libgo/go/encoding/json/stream.go b/libgo/go/encoding/json/stream.go
index e291274..81f404f 100644
--- a/libgo/go/encoding/json/stream.go
+++ b/libgo/go/encoding/json/stream.go
@@ -56,7 +56,7 @@ func (dec *Decoder) Decode(v interface{}) error {
 	}
 
 	if !dec.tokenValueAllowed() {
-		return &SyntaxError{msg: "not at beginning of value", Offset: dec.offset()}
+		return &SyntaxError{msg: "not at beginning of value", Offset: dec.InputOffset()}
 	}
 
 	// Read whole value into buffer.
@@ -102,6 +102,10 @@ Input:
 			dec.scan.bytes++
 			switch dec.scan.step(&dec.scan, c) {
 			case scanEnd:
+				// scanEnd is delayed one byte so we decrement
+				// the scanner bytes count by 1 to ensure that
+				// this value is correct in the next call of Decode.
+				dec.scan.bytes--
 				break Input
 			case scanEndObject, scanEndArray:
 				// scanEnd is delayed one byte.
@@ -310,7 +314,7 @@ func (dec *Decoder) tokenPrepareForDecode() error {
 			return err
 		}
 		if c != ',' {
-			return &SyntaxError{"expected comma after array element", dec.offset()}
+			return &SyntaxError{"expected comma after array element", dec.InputOffset()}
 		}
 		dec.scanp++
 		dec.tokenState = tokenArrayValue
@@ -320,7 +324,7 @@ func (dec *Decoder) tokenPrepareForDecode() error {
 			return err
 		}
 		if c != ':' {
-			return &SyntaxError{"expected colon after object key", dec.offset()}
+			return &SyntaxError{"expected colon after object key", dec.InputOffset()}
 		}
 		dec.scanp++
 		dec.tokenState = tokenObjectValue
@@ -473,7 +477,7 @@ func (dec *Decoder) tokenError(c byte) (Token, error) {
 	case tokenObjectComma:
 		context = " after object key:value pair"
 	}
-	return nil, &SyntaxError{"invalid character " + quoteChar(c) + context, dec.offset()}
+	return nil, &SyntaxError{"invalid character " + quoteChar(c) + context, dec.InputOffset()}
 }
 
 // More reports whether there is another element in the
@@ -502,6 +506,9 @@ func (dec *Decoder) peek() (byte, error) {
 	}
 }
 
-func (dec *Decoder) offset() int64 {
+// InputOffset returns the input stream byte offset of the current decoder position.
+// The offset gives the location of the end of the most recently returned token
+// and the beginning of the next token.
+func (dec *Decoder) InputOffset() int64 {
 	return dec.scanned + int64(dec.scanp)
 }
diff --git a/libgo/go/encoding/json/stream_test.go b/libgo/go/encoding/json/stream_test.go
index e3317dd..ebb4f23 100644
--- a/libgo/go/encoding/json/stream_test.go
+++ b/libgo/go/encoding/json/stream_test.go
@@ -118,6 +118,11 @@ func TestEncoderSetEscapeHTML(t *testing.T) {
 		Ptr    strPtrMarshaler
 	}{`"<str>"`, `"<str>"`}
 
+	// https://golang.org/issue/34154
+	stringOption := struct {
+		Bar string `json:"bar,string"`
+	}{`<html>foobar</html>`}
+
 	for _, tt := range []struct {
 		name       string
 		v          interface{}
@@ -137,6 +142,11 @@ func TestEncoderSetEscapeHTML(t *testing.T) {
 			`{"NonPtr":"\u003cstr\u003e","Ptr":"\u003cstr\u003e"}`,
 			`{"NonPtr":"<str>","Ptr":"<str>"}`,
 		},
+		{
+			"stringOption", stringOption,
+			`{"bar":"\"\u003chtml\u003efoobar\u003c/html\u003e\""}`,
+			`{"bar":"\"<html>foobar</html>\""}`,
+		},
 	} {
 		var buf bytes.Buffer
 		enc := NewEncoder(&buf)
diff --git a/libgo/go/encoding/xml/marshal.go b/libgo/go/encoding/xml/marshal.go
index add5ece..e325f31 100644
--- a/libgo/go/encoding/xml/marshal.go
+++ b/libgo/go/encoding/xml/marshal.go
@@ -914,7 +914,7 @@ func (p *printer) marshalStruct(tinfo *typeInfo, val reflect.Value) error {
 			p.WriteString("-->")
 			continue
 
-		case fInnerXml:
+		case fInnerXML:
 			vf = indirect(vf)
 			iface := vf.Interface()
 			switch raw := iface.(type) {
diff --git a/libgo/go/encoding/xml/marshal_test.go b/libgo/go/encoding/xml/marshal_test.go
index a0ccf44..8473158b 100644
--- a/libgo/go/encoding/xml/marshal_test.go
+++ b/libgo/go/encoding/xml/marshal_test.go
@@ -392,7 +392,6 @@ func stringptr(x string) *string {
 
 type T1 struct{}
 type T2 struct{}
-type T3 struct{}
 
 type IndirComment struct {
 	T1      T1
diff --git a/libgo/go/encoding/xml/read.go b/libgo/go/encoding/xml/read.go
index 12102bc..10a60ee 100644
--- a/libgo/go/encoding/xml/read.go
+++ b/libgo/go/encoding/xml/read.go
@@ -491,7 +491,7 @@ func (d *Decoder) unmarshal(val reflect.Value, start *StartElement) error {
 					saveAny = finfo.value(sv)
 				}
 
-			case fInnerXml:
+			case fInnerXML:
 				if !saveXML.IsValid() {
 					saveXML = finfo.value(sv)
 					if d.saved == nil {
diff --git a/libgo/go/encoding/xml/typeinfo.go b/libgo/go/encoding/xml/typeinfo.go
index 48de3d7..639952c 100644
--- a/libgo/go/encoding/xml/typeinfo.go
+++ b/libgo/go/encoding/xml/typeinfo.go
@@ -33,13 +33,13 @@ const (
 	fAttr
 	fCDATA
 	fCharData
-	fInnerXml
+	fInnerXML
 	fComment
 	fAny
 
 	fOmitEmpty
 
-	fMode = fElement | fAttr | fCDATA | fCharData | fInnerXml | fComment | fAny
+	fMode = fElement | fAttr | fCDATA | fCharData | fInnerXML | fComment | fAny
 
 	xmlName = "XMLName"
 )
@@ -134,7 +134,7 @@ func structFieldInfo(typ reflect.Type, f *reflect.StructField) (*fieldInfo, erro
 			case "chardata":
 				finfo.flags |= fCharData
 			case "innerxml":
-				finfo.flags |= fInnerXml
+				finfo.flags |= fInnerXML
 			case "comment":
 				finfo.flags |= fComment
 			case "any":
@@ -149,7 +149,7 @@ func structFieldInfo(typ reflect.Type, f *reflect.StructField) (*fieldInfo, erro
 		switch mode := finfo.flags & fMode; mode {
 		case 0:
 			finfo.flags |= fElement
-		case fAttr, fCDATA, fCharData, fInnerXml, fComment, fAny, fAny | fAttr:
+		case fAttr, fCDATA, fCharData, fInnerXML, fComment, fAny, fAny | fAttr:
 			if f.Name == xmlName || tag != "" && mode != fAttr {
 				valid = false
 			}
diff --git a/libgo/go/encoding/xml/xml.go b/libgo/go/encoding/xml/xml.go
index ca05944..5e73dcf 100644
--- a/libgo/go/encoding/xml/xml.go
+++ b/libgo/go/encoding/xml/xml.go
@@ -286,7 +286,10 @@ func (d *Decoder) Token() (Token, error) {
 		t = d.nextToken
 		d.nextToken = nil
 	} else if t, err = d.rawToken(); err != nil {
-		if err == io.EOF && d.stk != nil && d.stk.kind != stkEOF {
+		switch {
+		case err == io.EOF && d.t != nil:
+			err = nil
+		case err == io.EOF && d.stk != nil && d.stk.kind != stkEOF:
 			err = d.syntaxError("unexpected EOF")
 		}
 		return t, err
diff --git a/libgo/go/encoding/xml/xml_test.go b/libgo/go/encoding/xml/xml_test.go
index ee4ffa2..efddca4 100644
--- a/libgo/go/encoding/xml/xml_test.go
+++ b/libgo/go/encoding/xml/xml_test.go
@@ -14,6 +14,51 @@ import (
 	"unicode/utf8"
 )
 
+type toks struct {
+	earlyEOF bool
+	t        []Token
+}
+
+func (t *toks) Token() (Token, error) {
+	if len(t.t) == 0 {
+		return nil, io.EOF
+	}
+	var tok Token
+	tok, t.t = t.t[0], t.t[1:]
+	if t.earlyEOF && len(t.t) == 0 {
+		return tok, io.EOF
+	}
+	return tok, nil
+}
+
+func TestDecodeEOF(t *testing.T) {
+	start := StartElement{Name: Name{Local: "test"}}
+	t.Run("EarlyEOF", func(t *testing.T) {
+		d := NewTokenDecoder(&toks{earlyEOF: true, t: []Token{
+			start,
+			start.End(),
+		}})
+		err := d.Decode(&struct {
+			XMLName Name `xml:"test"`
+		}{})
+		if err != nil {
+			t.Error(err)
+		}
+	})
+	t.Run("LateEOF", func(t *testing.T) {
+		d := NewTokenDecoder(&toks{t: []Token{
+			start,
+			start.End(),
+		}})
+		err := d.Decode(&struct {
+			XMLName Name `xml:"test"`
+		}{})
+		if err != nil {
+			t.Error(err)
+		}
+	})
+}
+
 const testInput = `
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"