libgo: update to Go 1.8 release candidate 1

    
    Compiler changes:
      * Change map assignment to use mapassign and assign value directly.
      * Change string iteration to use decoderune, faster for ASCII strings.
      * Change makeslice to take int, and use makeslice64 for larger values.
      * Add new noverflow field to hmap struct used for maps.
    
    Unresolved problems, to be fixed later:
      * Commented out test in go/types/sizes_test.go that doesn't compile.
      * Commented out reflect.TestStructOf test for padding after zero-sized field.
    
    Reviewed-on: https://go-review.googlesource.com/35231

gotools/:
	Updates for Go 1.8rc1.
	* Makefile.am (go_cmd_go_files): Add bug.go.
	(s-zdefaultcc): Write defaultPkgConfig.
	* Makefile.in: Rebuild.

From-SVN: r244456

8 files changed, 794 insertions, 83 deletions

diff --git a/libgo/go/bytes/buffer.go b/libgo/go/bytes/buffer.go
index 9154a1b..196419d 100644
--- a/libgo/go/bytes/buffer.go
+++ b/libgo/go/bytes/buffer.go
@@ -15,22 +15,25 @@ import (
 // A Buffer is a variable-sized buffer of bytes with Read and Write methods.
 // The zero value for Buffer is an empty buffer ready to use.
 type Buffer struct {
-	buf       []byte            // contents are the bytes buf[off : len(buf)]
-	off       int               // read at &buf[off], write at &buf[len(buf)]
-	runeBytes [utf8.UTFMax]byte // avoid allocation of slice on each call to WriteRune
-	bootstrap [64]byte          // memory to hold first slice; helps small buffers avoid allocation.
-	lastRead  readOp            // last read operation, so that Unread* can work correctly.
+	buf       []byte   // contents are the bytes buf[off : len(buf)]
+	off       int      // read at &buf[off], write at &buf[len(buf)]
+	bootstrap [64]byte // memory to hold first slice; helps small buffers avoid allocation.
+	lastRead  readOp   // last read operation, so that Unread* can work correctly.
 }
 
 // The readOp constants describe the last action performed on
-// the buffer, so that UnreadRune and UnreadByte can
-// check for invalid usage.
+// the buffer, so that UnreadRune and UnreadByte can check for
+// invalid usage. opReadRuneX constants are chosen such that
+// converted to int they correspond to the rune size that was read.
 type readOp int
 
 const (
-	opInvalid  readOp = iota // Non-read operation.
-	opReadRune               // Read rune.
-	opRead                   // Any other read operation.
+	opRead      readOp = -1 // Any other read operation.
+	opInvalid          = 0  // Non-read operation.
+	opReadRune1        = 1  // Read rune of size 1.
+	opReadRune2        = 2  // Read rune of size 2.
+	opReadRune3        = 3  // Read rune of size 3.
+	opReadRune4        = 4  // Read rune of size 4.
 )
 
 // ErrTooLarge is passed to panic if memory cannot be allocated to store data in a buffer.
@@ -246,8 +249,10 @@ func (b *Buffer) WriteRune(r rune) (n int, err error) {
 		b.WriteByte(byte(r))
 		return 1, nil
 	}
-	n = utf8.EncodeRune(b.runeBytes[0:], r)
-	b.Write(b.runeBytes[0:n])
+	b.lastRead = opInvalid
+	m := b.grow(utf8.UTFMax)
+	n = utf8.EncodeRune(b.buf[m:m+utf8.UTFMax], r)
+	b.buf = b.buf[:m+n]
 	return n, nil
 }
 
@@ -318,14 +323,15 @@ func (b *Buffer) ReadRune() (r rune, size int, err error) {
 		b.Truncate(0)
 		return 0, 0, io.EOF
 	}
-	b.lastRead = opReadRune
 	c := b.buf[b.off]
 	if c < utf8.RuneSelf {
 		b.off++
+		b.lastRead = opReadRune1
 		return rune(c), 1, nil
 	}
 	r, n := utf8.DecodeRune(b.buf[b.off:])
 	b.off += n
+	b.lastRead = readOp(n)
 	return r, n, nil
 }
 
@@ -335,14 +341,13 @@ func (b *Buffer) ReadRune() (r rune, size int, err error) {
 // it is stricter than UnreadByte, which will unread the last byte
 // from any read operation.)
 func (b *Buffer) UnreadRune() error {
-	if b.lastRead != opReadRune {
+	if b.lastRead <= opInvalid {
 		return errors.New("bytes.Buffer: UnreadRune: previous operation was not ReadRune")
 	}
-	b.lastRead = opInvalid
-	if b.off > 0 {
-		_, n := utf8.DecodeLastRune(b.buf[0:b.off])
-		b.off -= n
+	if b.off >= int(b.lastRead) {
+		b.off -= int(b.lastRead)
 	}
+	b.lastRead = opInvalid
 	return nil
 }
 
@@ -350,7 +355,7 @@ func (b *Buffer) UnreadRune() error {
 // read operation. If write has happened since the last read, UnreadByte
 // returns an error.
 func (b *Buffer) UnreadByte() error {
-	if b.lastRead != opReadRune && b.lastRead != opRead {
+	if b.lastRead == opInvalid {
 		return errors.New("bytes.Buffer: UnreadByte: previous operation was not a read")
 	}
 	b.lastRead = opInvalid
diff --git a/libgo/go/bytes/buffer_test.go b/libgo/go/bytes/buffer_test.go
index 7de17ae..b1b85f9 100644
--- a/libgo/go/bytes/buffer_test.go
+++ b/libgo/go/bytes/buffer_test.go
@@ -514,6 +514,19 @@ func TestBufferGrowth(t *testing.T) {
 	}
 }
 
+func BenchmarkWriteRune(b *testing.B) {
+	const n = 4 << 10
+	const r = '☺'
+	b.SetBytes(int64(n * utf8.RuneLen(r)))
+	buf := NewBuffer(make([]byte, n*utf8.UTFMax))
+	for i := 0; i < b.N; i++ {
+		buf.Reset()
+		for i := 0; i < n; i++ {
+			buf.WriteRune(r)
+		}
+	}
+}
+
 // From Issue 5154.
 func BenchmarkBufferNotEmptyWriteRead(b *testing.B) {
 	buf := make([]byte, 1024)
diff --git a/libgo/go/bytes/bytes.go b/libgo/go/bytes/bytes.go
index 305c85d..406a3825 100644
--- a/libgo/go/bytes/bytes.go
+++ b/libgo/go/bytes/bytes.go
@@ -93,37 +93,6 @@ func ContainsRune(b []byte, r rune) bool {
 	return IndexRune(b, r) >= 0
 }
 
-// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
-func Index(s, sep []byte) int {
-	n := len(sep)
-	if n == 0 {
-		return 0
-	}
-	if n > len(s) {
-		return -1
-	}
-	c := sep[0]
-	if n == 1 {
-		return IndexByte(s, c)
-	}
-	i := 0
-	t := s[:len(s)-n+1]
-	for i < len(t) {
-		if t[i] != c {
-			o := IndexByte(t[i:], c)
-			if o < 0 {
-				break
-			}
-			i += o
-		}
-		if Equal(s[i:i+n], sep) {
-			return i
-		}
-		i++
-	}
-	return -1
-}
-
 func indexBytePortable(s []byte, c byte) int {
 	for i, b := range s {
 		if b == c {
@@ -161,15 +130,28 @@ func LastIndexByte(s []byte, c byte) int {
 // IndexRune interprets s as a sequence of UTF-8-encoded Unicode code points.
 // It returns the byte index of the first occurrence in s of the given rune.
 // It returns -1 if rune is not present in s.
+// If r is utf8.RuneError, it returns the first instance of any
+// invalid UTF-8 byte sequence.
 func IndexRune(s []byte, r rune) int {
-	for i := 0; i < len(s); {
-		r1, size := utf8.DecodeRune(s[i:])
-		if r == r1 {
-			return i
+	switch {
+	case 0 <= r && r < utf8.RuneSelf:
+		return IndexByte(s, byte(r))
+	case r == utf8.RuneError:
+		for i := 0; i < len(s); {
+			r1, n := utf8.DecodeRune(s[i:])
+			if r1 == utf8.RuneError {
+				return i
+			}
+			i += n
 		}
-		i += size
+		return -1
+	case !utf8.ValidRune(r):
+		return -1
+	default:
+		var b [utf8.UTFMax]byte
+		n := utf8.EncodeRune(b[:], r)
+		return Index(s, b[:n])
 	}
-	return -1
 }
 
 // IndexAny interprets s as a sequence of UTF-8-encoded Unicode code points.
@@ -178,10 +160,19 @@ func IndexRune(s []byte, r rune) int {
 // point in common.
 func IndexAny(s []byte, chars string) int {
 	if len(chars) > 0 {
-		var r rune
+		if len(s) > 8 {
+			if as, isASCII := makeASCIISet(chars); isASCII {
+				for i, c := range s {
+					if as.contains(c) {
+						return i
+					}
+				}
+				return -1
+			}
+		}
 		var width int
 		for i := 0; i < len(s); i += width {
-			r = rune(s[i])
+			r := rune(s[i])
 			if r < utf8.RuneSelf {
 				width = 1
 			} else {
@@ -203,11 +194,21 @@ func IndexAny(s []byte, chars string) int {
 // there is no code point in common.
 func LastIndexAny(s []byte, chars string) int {
 	if len(chars) > 0 {
+		if len(s) > 8 {
+			if as, isASCII := makeASCIISet(chars); isASCII {
+				for i := len(s) - 1; i >= 0; i-- {
+					if as.contains(s[i]) {
+						return i
+					}
+				}
+				return -1
+			}
+		}
 		for i := len(s); i > 0; {
-			r, size := utf8.DecodeLastRune(s[0:i])
+			r, size := utf8.DecodeLastRune(s[:i])
 			i -= size
-			for _, ch := range chars {
-				if r == ch {
+			for _, c := range chars {
+				if r == c {
 					return i
 				}
 			}
@@ -398,7 +399,20 @@ func Map(mapping func(r rune) rune, s []byte) []byte {
 }
 
 // Repeat returns a new byte slice consisting of count copies of b.
+//
+// It panics if count is negative or if
+// the result of (len(b) * count) overflows.
 func Repeat(b []byte, count int) []byte {
+	// Since we cannot return an error on overflow,
+	// we should panic if the repeat will generate
+	// an overflow.
+	// See Issue golang.org/issue/16237.
+	if count < 0 {
+		panic("bytes: negative Repeat count")
+	} else if count > 0 && len(b)*count/count != len(b) {
+		panic("bytes: Repeat count causes overflow")
+	}
+
 	nb := make([]byte, len(b)*count)
 	bp := copy(nb, b)
 	for bp < len(nb) {
@@ -419,20 +433,20 @@ func ToTitle(s []byte) []byte { return Map(unicode.ToTitle, s) }
 
 // ToUpperSpecial returns a copy of the byte slice s with all Unicode letters mapped to their
 // upper case, giving priority to the special casing rules.
-func ToUpperSpecial(_case unicode.SpecialCase, s []byte) []byte {
-	return Map(func(r rune) rune { return _case.ToUpper(r) }, s)
+func ToUpperSpecial(c unicode.SpecialCase, s []byte) []byte {
+	return Map(func(r rune) rune { return c.ToUpper(r) }, s)
 }
 
 // ToLowerSpecial returns a copy of the byte slice s with all Unicode letters mapped to their
 // lower case, giving priority to the special casing rules.
-func ToLowerSpecial(_case unicode.SpecialCase, s []byte) []byte {
-	return Map(func(r rune) rune { return _case.ToLower(r) }, s)
+func ToLowerSpecial(c unicode.SpecialCase, s []byte) []byte {
+	return Map(func(r rune) rune { return c.ToLower(r) }, s)
 }
 
 // ToTitleSpecial returns a copy of the byte slice s with all Unicode letters mapped to their
 // title case, giving priority to the special casing rules.
-func ToTitleSpecial(_case unicode.SpecialCase, s []byte) []byte {
-	return Map(func(r rune) rune { return _case.ToTitle(r) }, s)
+func ToTitleSpecial(c unicode.SpecialCase, s []byte) []byte {
+	return Map(func(r rune) rune { return c.ToTitle(r) }, s)
 }
 
 // isSeparator reports whether the rune could mark a word boundary.
@@ -578,7 +592,43 @@ func lastIndexFunc(s []byte, f func(r rune) bool, truth bool) int {
 	return -1
 }
 
+// asciiSet is a 32-byte value, where each bit represents the presence of a
+// given ASCII character in the set. The 128-bits of the lower 16 bytes,
+// starting with the least-significant bit of the lowest word to the
+// most-significant bit of the highest word, map to the full range of all
+// 128 ASCII characters. The 128-bits of the upper 16 bytes will be zeroed,
+// ensuring that any non-ASCII character will be reported as not in the set.
+type asciiSet [8]uint32
+
+// makeASCIISet creates a set of ASCII characters and reports whether all
+// characters in chars are ASCII.
+func makeASCIISet(chars string) (as asciiSet, ok bool) {
+	for i := 0; i < len(chars); i++ {
+		c := chars[i]
+		if c >= utf8.RuneSelf {
+			return as, false
+		}
+		as[c>>5] |= 1 << uint(c&31)
+	}
+	return as, true
+}
+
+// contains reports whether c is inside the set.
+func (as *asciiSet) contains(c byte) bool {
+	return (as[c>>5] & (1 << uint(c&31))) != 0
+}
+
 func makeCutsetFunc(cutset string) func(r rune) bool {
+	if len(cutset) == 1 && cutset[0] < utf8.RuneSelf {
+		return func(r rune) bool {
+			return r == rune(cutset[0])
+		}
+	}
+	if as, isASCII := makeASCIISet(cutset); isASCII {
+		return func(r rune) bool {
+			return r < utf8.RuneSelf && as.contains(byte(r))
+		}
+	}
 	return func(r rune) bool {
 		for _, c := range cutset {
 			if c == r {
diff --git a/libgo/go/bytes/bytes_amd64.go b/libgo/go/bytes/bytes_amd64.go
new file mode 100644
index 0000000..58a07ef
--- /dev/null
+++ b/libgo/go/bytes/bytes_amd64.go
@@ -0,0 +1,117 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore
+
+package bytes
+
+//go:noescape
+
+// indexShortStr returns the index of the first instance of c in s, or -1 if c is not present in s.
+// indexShortStr requires 2 <= len(c) <= shortStringLen
+func indexShortStr(s, c []byte) int // ../runtime/asm_$GOARCH.s
+func supportAVX2() bool             // ../runtime/asm_$GOARCH.s
+
+var shortStringLen int
+
+func init() {
+	if supportAVX2() {
+		shortStringLen = 63
+	} else {
+		shortStringLen = 31
+	}
+}
+
+// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
+func Index(s, sep []byte) int {
+	n := len(sep)
+	switch {
+	case n == 0:
+		return 0
+	case n == 1:
+		return IndexByte(s, sep[0])
+	case n == len(s):
+		if Equal(sep, s) {
+			return 0
+		}
+		return -1
+	case n > len(s):
+		return -1
+	case n <= shortStringLen:
+		// Use brute force when s and sep both are small
+		if len(s) <= 64 {
+			return indexShortStr(s, sep)
+		}
+		c := sep[0]
+		i := 0
+		t := s[:len(s)-n+1]
+		fails := 0
+		for i < len(t) {
+			if t[i] != c {
+				// IndexByte skips 16/32 bytes per iteration,
+				// so it's faster than indexShortStr.
+				o := IndexByte(t[i:], c)
+				if o < 0 {
+					return -1
+				}
+				i += o
+			}
+			if Equal(s[i:i+n], sep) {
+				return i
+			}
+			fails++
+			i++
+			// Switch to indexShortStr when IndexByte produces too many false positives.
+			// Too many means more that 1 error per 8 characters.
+			// Allow some errors in the beginning.
+			if fails > (i+16)/8 {
+				r := indexShortStr(s[i:], sep)
+				if r >= 0 {
+					return r + i
+				}
+				return -1
+			}
+		}
+		return -1
+	}
+	// Rabin-Karp search
+	hashsep, pow := hashStr(sep)
+	var h uint32
+	for i := 0; i < n; i++ {
+		h = h*primeRK + uint32(s[i])
+	}
+	if h == hashsep && Equal(s[:n], sep) {
+		return 0
+	}
+	for i := n; i < len(s); {
+		h *= primeRK
+		h += uint32(s[i])
+		h -= pow * uint32(s[i-n])
+		i++
+		if h == hashsep && Equal(s[i-n:i], sep) {
+			return i - n
+		}
+	}
+	return -1
+}
+
+// primeRK is the prime base used in Rabin-Karp algorithm.
+const primeRK = 16777619
+
+// hashStr returns the hash and the appropriate multiplicative
+// factor for use in Rabin-Karp algorithm.
+func hashStr(sep []byte) (uint32, uint32) {
+	hash := uint32(0)
+	for i := 0; i < len(sep); i++ {
+		hash = hash*primeRK + uint32(sep[i])
+	}
+	var pow, sq uint32 = 1, primeRK
+	for i := len(sep); i > 0; i >>= 1 {
+		if i&1 != 0 {
+			pow *= sq
+		}
+		sq *= sq
+	}
+	return hash, pow
+}
diff --git a/libgo/go/bytes/bytes_generic.go b/libgo/go/bytes/bytes_generic.go
new file mode 100644
index 0000000..91baa22
--- /dev/null
+++ b/libgo/go/bytes/bytes_generic.go
@@ -0,0 +1,41 @@
+// Copyright 2015 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// -build !amd64,!s390x
+
+package bytes
+
+// TODO: implements short string optimization on non amd64 platforms
+// and get rid of bytes_amd64.go
+
+// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
+func Index(s, sep []byte) int {
+	n := len(sep)
+	if n == 0 {
+		return 0
+	}
+	if n > len(s) {
+		return -1
+	}
+	c := sep[0]
+	if n == 1 {
+		return IndexByte(s, c)
+	}
+	i := 0
+	t := s[:len(s)-n+1]
+	for i < len(t) {
+		if t[i] != c {
+			o := IndexByte(t[i:], c)
+			if o < 0 {
+				break
+			}
+			i += o
+		}
+		if Equal(s[i:i+n], sep) {
+			return i
+		}
+		i++
+	}
+	return -1
+}
diff --git a/libgo/go/bytes/bytes_s390x.go b/libgo/go/bytes/bytes_s390x.go
new file mode 100644
index 0000000..a05ca47
--- /dev/null
+++ b/libgo/go/bytes/bytes_s390x.go
@@ -0,0 +1,120 @@
+// Copyright 2016 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build ignore
+
+package bytes
+
+//go:noescape
+
+// indexShortStr returns the index of the first instance of sep in s,
+// or -1 if sep is not present in s.
+// indexShortStr requires 2 <= len(sep) <= shortStringLen
+func indexShortStr(s, c []byte) int // ../runtime/asm_s390x.s
+
+// supportsVX reports whether the vector facility is available.
+// indexShortStr must not be called if the vector facility is not
+// available.
+func supportsVX() bool // ../runtime/asm_s390x.s
+
+var shortStringLen = -1
+
+func init() {
+	if supportsVX() {
+		shortStringLen = 64
+	}
+}
+
+// Index returns the index of the first instance of sep in s, or -1 if sep is not present in s.
+func Index(s, sep []byte) int {
+	n := len(sep)
+	switch {
+	case n == 0:
+		return 0
+	case n == 1:
+		return IndexByte(s, sep[0])
+	case n == len(s):
+		if Equal(sep, s) {
+			return 0
+		}
+		return -1
+	case n > len(s):
+		return -1
+	case n <= shortStringLen:
+		// Use brute force when s and sep both are small
+		if len(s) <= 64 {
+			return indexShortStr(s, sep)
+		}
+		c := sep[0]
+		i := 0
+		t := s[:len(s)-n+1]
+		fails := 0
+		for i < len(t) {
+			if t[i] != c {
+				// IndexByte skips 16/32 bytes per iteration,
+				// so it's faster than indexShortStr.
+				o := IndexByte(t[i:], c)
+				if o < 0 {
+					return -1
+				}
+				i += o
+			}
+			if Equal(s[i:i+n], sep) {
+				return i
+			}
+			fails++
+			i++
+			// Switch to indexShortStr when IndexByte produces too many false positives.
+			// Too many means more that 1 error per 8 characters.
+			// Allow some errors in the beginning.
+			if fails > (i+16)/8 {
+				r := indexShortStr(s[i:], sep)
+				if r >= 0 {
+					return r + i
+				}
+				return -1
+			}
+		}
+		return -1
+	}
+	// Rabin-Karp search
+	hashsep, pow := hashStr(sep)
+	var h uint32
+	for i := 0; i < n; i++ {
+		h = h*primeRK + uint32(s[i])
+	}
+	if h == hashsep && Equal(s[:n], sep) {
+		return 0
+	}
+	for i := n; i < len(s); {
+		h *= primeRK
+		h += uint32(s[i])
+		h -= pow * uint32(s[i-n])
+		i++
+		if h == hashsep && Equal(s[i-n:i], sep) {
+			return i - n
+		}
+	}
+	return -1
+}
+
+// primeRK is the prime base used in Rabin-Karp algorithm.
+const primeRK = 16777619
+
+// hashStr returns the hash and the appropriate multiplicative
+// factor for use in Rabin-Karp algorithm.
+func hashStr(sep []byte) (uint32, uint32) {
+	hash := uint32(0)
+	for i := 0; i < len(sep); i++ {
+		hash = hash*primeRK + uint32(sep[i])
+	}
+	var pow, sq uint32 = 1, primeRK
+	for i := len(sep); i > 0; i >>= 1 {
+		if i&1 != 0 {
+			pow *= sq
+		}
+		sq *= sq
+	}
+	return hash, pow
+}
diff --git a/libgo/go/bytes/bytes_test.go b/libgo/go/bytes/bytes_test.go
index c48f662..26eac5e 100644
--- a/libgo/go/bytes/bytes_test.go
+++ b/libgo/go/bytes/bytes_test.go
@@ -7,8 +7,10 @@ package bytes_test
 import (
 	. "bytes"
 	"fmt"
+	"internal/testenv"
 	"math/rand"
 	"reflect"
+	"strings"
 	"testing"
 	"unicode"
 	"unicode/utf8"
@@ -165,8 +167,12 @@ var indexAnyTests = []BinOpTest{
 	{"abc", "xyz", -1},
 	{"abc", "xcz", 2},
 	{"ab☺c", "x☺yz", 2},
+	{"a☺b☻c☹d", "cx", len("a☺b☻")},
+	{"a☺b☻c☹d", "uvw☻xyz", len("a☺b")},
 	{"aRegExp*", ".(|)*+?^$[]", 7},
 	{dots + dots + dots, " ", -1},
+	{"012abcba210", "\xffb", 4},
+	{"012\x80bcb\x80210", "\xffb", 3},
 }
 
 var lastIndexAnyTests = []BinOpTest{
@@ -178,18 +184,13 @@ var lastIndexAnyTests = []BinOpTest{
 	{"aaa", "a", 2},
 	{"abc", "xyz", -1},
 	{"abc", "ab", 1},
-	{"a☺b☻c☹d", "uvw☻xyz", 2 + len("☺")},
+	{"ab☺c", "x☺yz", 2},
+	{"a☺b☻c☹d", "cx", len("a☺b☻")},
+	{"a☺b☻c☹d", "uvw☻xyz", len("a☺b")},
 	{"a.RegExp*", ".(|)*+?^$[]", 8},
 	{dots + dots + dots, " ", -1},
-}
-
-var indexRuneTests = []BinOpTest{
-	{"", "a", -1},
-	{"", "☺", -1},
-	{"foo", "☹", -1},
-	{"foo", "o", 1},
-	{"foo☺bar", "☺", 3},
-	{"foo☺☻☹bar", "☹", 9},
+	{"012abcba210", "\xffb", 6},
+	{"012\x80bcb\x80210", "\xffb", 7},
 }
 
 // Execute f on each test case.  funcName should be the name of f; it's used
@@ -346,13 +347,52 @@ func TestIndexByteSmall(t *testing.T) {
 }
 
 func TestIndexRune(t *testing.T) {
-	for _, tt := range indexRuneTests {
-		a := []byte(tt.a)
-		r, _ := utf8.DecodeRuneInString(tt.b)
-		pos := IndexRune(a, r)
-		if pos != tt.i {
-			t.Errorf(`IndexRune(%q, '%c') = %v`, tt.a, r, pos)
+	tests := []struct {
+		in   string
+		rune rune
+		want int
+	}{
+		{"", 'a', -1},
+		{"", '☺', -1},
+		{"foo", '☹', -1},
+		{"foo", 'o', 1},
+		{"foo☺bar", '☺', 3},
+		{"foo☺☻☹bar", '☹', 9},
+		{"a A x", 'A', 2},
+		{"some_text=some_value", '=', 9},
+		{"☺a", 'a', 3},
+		{"a☻☺b", '☺', 4},
+
+		// RuneError should match any invalid UTF-8 byte sequence.
+		{"�", '�', 0},
+		{"\xff", '�', 0},
+		{"☻x�", '�', len("☻x")},
+		{"☻x\xe2\x98", '�', len("☻x")},
+		{"☻x\xe2\x98�", '�', len("☻x")},
+		{"☻x\xe2\x98x", '�', len("☻x")},
+
+		// Invalid rune values should never match.
+		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", -1, -1},
+		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", 0xD800, -1}, // Surrogate pair
+		{"a☺b☻c☹d\xe2\x98�\xff�\xed\xa0\x80", utf8.MaxRune + 1, -1},
+	}
+	for _, tt := range tests {
+		if got := IndexRune([]byte(tt.in), tt.rune); got != tt.want {
+			t.Errorf("IndexRune(%q, %d) = %v; want %v", tt.in, tt.rune, got, tt.want)
+		}
+	}
+
+	haystack := []byte("test世界")
+	allocs := testing.AllocsPerRun(1000, func() {
+		if i := IndexRune(haystack, 's'); i != 2 {
+			t.Fatalf("'s' at %d; want 2", i)
+		}
+		if i := IndexRune(haystack, '世'); i != 4 {
+			t.Fatalf("'世' at %d; want 4", i)
 		}
+	})
+	if allocs != 0 {
+		t.Errorf("expected no allocations, got %f", allocs)
 	}
 }
 
@@ -370,6 +410,9 @@ func valName(x int) string {
 
 func benchBytes(b *testing.B, sizes []int, f func(b *testing.B, n int)) {
 	for _, n := range sizes {
+		if isRaceBuilder && n > 4<<10 {
+			continue
+		}
 		b.Run(valName(n), func(b *testing.B) {
 			if len(bmbuf) < n {
 				bmbuf = make([]byte, n)
@@ -382,6 +425,8 @@ func benchBytes(b *testing.B, sizes []int, f func(b *testing.B, n int)) {
 
 var indexSizes = []int{10, 32, 4 << 10, 4 << 20, 64 << 20}
 
+var isRaceBuilder = strings.HasSuffix(testenv.Builder(), "-race")
+
 func BenchmarkIndexByte(b *testing.B) {
 	benchBytes(b, indexSizes, bmIndexByte(IndexByte))
 }
@@ -404,6 +449,44 @@ func bmIndexByte(index func([]byte, byte) int) func(b *testing.B, n int) {
 	}
 }
 
+func BenchmarkIndexRune(b *testing.B) {
+	benchBytes(b, indexSizes, bmIndexRune(IndexRune))
+}
+
+func BenchmarkIndexRuneASCII(b *testing.B) {
+	benchBytes(b, indexSizes, bmIndexRuneASCII(IndexRune))
+}
+
+func bmIndexRuneASCII(index func([]byte, rune) int) func(b *testing.B, n int) {
+	return func(b *testing.B, n int) {
+		buf := bmbuf[0:n]
+		buf[n-1] = 'x'
+		for i := 0; i < b.N; i++ {
+			j := index(buf, 'x')
+			if j != n-1 {
+				b.Fatal("bad index", j)
+			}
+		}
+		buf[n-1] = '\x00'
+	}
+}
+
+func bmIndexRune(index func([]byte, rune) int) func(b *testing.B, n int) {
+	return func(b *testing.B, n int) {
+		buf := bmbuf[0:n]
+		utf8.EncodeRune(buf[n-3:], '世')
+		for i := 0; i < b.N; i++ {
+			j := index(buf, '世')
+			if j != n-3 {
+				b.Fatal("bad index", j)
+			}
+		}
+		buf[n-3] = '\x00'
+		buf[n-2] = '\x00'
+		buf[n-1] = '\x00'
+	}
+}
+
 func BenchmarkEqual(b *testing.B) {
 	b.Run("0", func(b *testing.B) {
 		var buf [4]byte
@@ -844,6 +927,54 @@ func TestRepeat(t *testing.T) {
 	}
 }
 
+func repeat(b []byte, count int) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			switch v := r.(type) {
+			case error:
+				err = v
+			default:
+				err = fmt.Errorf("%s", v)
+			}
+		}
+	}()
+
+	Repeat(b, count)
+
+	return
+}
+
+// See Issue golang.org/issue/16237
+func TestRepeatCatchesOverflow(t *testing.T) {
+	tests := [...]struct {
+		s      string
+		count  int
+		errStr string
+	}{
+		0: {"--", -2147483647, "negative"},
+		1: {"", int(^uint(0) >> 1), ""},
+		2: {"-", 10, ""},
+		3: {"gopher", 0, ""},
+		4: {"-", -1, "negative"},
+		5: {"--", -102, "negative"},
+		6: {string(make([]byte, 255)), int((^uint(0))/255 + 1), "overflow"},
+	}
+
+	for i, tt := range tests {
+		err := repeat([]byte(tt.s), tt.count)
+		if tt.errStr == "" {
+			if err != nil {
+				t.Errorf("#%d panicked %v", i, err)
+			}
+			continue
+		}
+
+		if err == nil || !strings.Contains(err.Error(), tt.errStr) {
+			t.Errorf("#%d expected %q got %q", i, tt.errStr, err)
+		}
+	}
+}
+
 func runesEqual(a, b []rune) bool {
 	if len(a) != len(b) {
 		return false
@@ -906,6 +1037,9 @@ var trimTests = []TrimTest{
 	{"Trim", "* listitem", " *", "listitem"},
 	{"Trim", `"quote"`, `"`, "quote"},
 	{"Trim", "\u2C6F\u2C6F\u0250\u0250\u2C6F\u2C6F", "\u2C6F", "\u0250\u0250"},
+	{"Trim", "\x80test\xff", "\xff", "test"},
+	{"Trim", " Ġ ", " ", "Ġ"},
+	{"Trim", " Ġİ0", "0 ", "Ġİ"},
 	//empty string tests
 	{"Trim", "abba", "", "abba"},
 	{"Trim", "", "123", ""},
@@ -1325,3 +1459,31 @@ func BenchmarkBytesCompare(b *testing.B) {
 		})
 	}
 }
+
+func BenchmarkIndexAnyASCII(b *testing.B) {
+	x := Repeat([]byte{'#'}, 4096) // Never matches set
+	cs := "0123456789abcdef"
+	for k := 1; k <= 4096; k <<= 4 {
+		for j := 1; j <= 16; j <<= 1 {
+			b.Run(fmt.Sprintf("%d:%d", k, j), func(b *testing.B) {
+				for i := 0; i < b.N; i++ {
+					IndexAny(x[:k], cs[:j])
+				}
+			})
+		}
+	}
+}
+
+func BenchmarkTrimASCII(b *testing.B) {
+	cs := "0123456789abcdef"
+	for k := 1; k <= 4096; k <<= 4 {
+		for j := 1; j <= 16; j <<= 1 {
+			b.Run(fmt.Sprintf("%d:%d", k, j), func(b *testing.B) {
+				x := Repeat([]byte(cs[:j]), k) // Always matches set
+				for i := 0; i < b.N; i++ {
+					Trim(x[:k], cs[:j])
+				}
+			})
+		}
+	}
+}
diff --git a/libgo/go/bytes/example_test.go b/libgo/go/bytes/example_test.go
index ad2dbc6..0d35a0d 100644
--- a/libgo/go/bytes/example_test.go
+++ b/libgo/go/bytes/example_test.go
@@ -11,6 +11,7 @@ import (
 	"io"
 	"os"
 	"sort"
+	"unicode"
 )
 
 func ExampleBuffer() {
@@ -83,3 +84,205 @@ func ExampleTrimPrefix() {
 	fmt.Printf("Hello%s", b)
 	// Output: Hello, world!
 }
+
+func ExampleFields() {
+	fmt.Printf("Fields are: %q", bytes.Fields([]byte("  foo bar  baz   ")))
+	// Output: Fields are: ["foo" "bar" "baz"]
+}
+
+func ExampleFieldsFunc() {
+	f := func(c rune) bool {
+		return !unicode.IsLetter(c) && !unicode.IsNumber(c)
+	}
+	fmt.Printf("Fields are: %q", bytes.FieldsFunc([]byte("  foo1;bar2,baz3..."), f))
+	// Output: Fields are: ["foo1" "bar2" "baz3"]
+}
+
+func ExampleContains() {
+	fmt.Println(bytes.Contains([]byte("seafood"), []byte("foo")))
+	fmt.Println(bytes.Contains([]byte("seafood"), []byte("bar")))
+	fmt.Println(bytes.Contains([]byte("seafood"), []byte("")))
+	fmt.Println(bytes.Contains([]byte(""), []byte("")))
+	// Output:
+	// true
+	// false
+	// true
+	// true
+}
+
+func ExampleCount() {
+	fmt.Println(bytes.Count([]byte("cheese"), []byte("e")))
+	fmt.Println(bytes.Count([]byte("five"), []byte(""))) // before & after each rune
+	// Output:
+	// 3
+	// 5
+}
+
+func ExampleEqualFold() {
+	fmt.Println(bytes.EqualFold([]byte("Go"), []byte("go")))
+	// Output: true
+}
+
+func ExampleHasPrefix() {
+	fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("Go")))
+	fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("C")))
+	fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("")))
+	// Output:
+	// true
+	// false
+	// true
+}
+
+func ExampleHasSuffix() {
+	fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("go")))
+	fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("O")))
+	fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("Ami")))
+	fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("")))
+	// Output:
+	// true
+	// false
+	// false
+	// true
+}
+
+func ExampleIndex() {
+	fmt.Println(bytes.Index([]byte("chicken"), []byte("ken")))
+	fmt.Println(bytes.Index([]byte("chicken"), []byte("dmr")))
+	// Output:
+	// 4
+	// -1
+}
+
+func ExampleIndexFunc() {
+	f := func(c rune) bool {
+		return unicode.Is(unicode.Han, c)
+	}
+	fmt.Println(bytes.IndexFunc([]byte("Hello, 世界"), f))
+	fmt.Println(bytes.IndexFunc([]byte("Hello, world"), f))
+	// Output:
+	// 7
+	// -1
+}
+
+func ExampleIndexAny() {
+	fmt.Println(bytes.IndexAny([]byte("chicken"), "aeiouy"))
+	fmt.Println(bytes.IndexAny([]byte("crwth"), "aeiouy"))
+	// Output:
+	// 2
+	// -1
+}
+
+func ExampleIndexRune() {
+	fmt.Println(bytes.IndexRune([]byte("chicken"), 'k'))
+	fmt.Println(bytes.IndexRune([]byte("chicken"), 'd'))
+	// Output:
+	// 4
+	// -1
+}
+
+func ExampleLastIndex() {
+	fmt.Println(bytes.Index([]byte("go gopher"), []byte("go")))
+	fmt.Println(bytes.LastIndex([]byte("go gopher"), []byte("go")))
+	fmt.Println(bytes.LastIndex([]byte("go gopher"), []byte("rodent")))
+	// Output:
+	// 0
+	// 3
+	// -1
+}
+
+func ExampleJoin() {
+	s := [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}
+	fmt.Printf("%s", bytes.Join(s, []byte(", ")))
+	// Output: foo, bar, baz
+}
+
+func ExampleRepeat() {
+	fmt.Printf("ba%s", bytes.Repeat([]byte("na"), 2))
+	// Output: banana
+}
+
+func ExampleReplace() {
+	fmt.Printf("%s\n", bytes.Replace([]byte("oink oink oink"), []byte("k"), []byte("ky"), 2))
+	fmt.Printf("%s\n", bytes.Replace([]byte("oink oink oink"), []byte("oink"), []byte("moo"), -1))
+	// Output:
+	// oinky oinky oink
+	// moo moo moo
+}
+
+func ExampleSplit() {
+	fmt.Printf("%q\n", bytes.Split([]byte("a,b,c"), []byte(",")))
+	fmt.Printf("%q\n", bytes.Split([]byte("a man a plan a canal panama"), []byte("a ")))
+	fmt.Printf("%q\n", bytes.Split([]byte(" xyz "), []byte("")))
+	fmt.Printf("%q\n", bytes.Split([]byte(""), []byte("Bernardo O'Higgins")))
+	// Output:
+	// ["a" "b" "c"]
+	// ["" "man " "plan " "canal panama"]
+	// [" " "x" "y" "z" " "]
+	// [""]
+}
+
+func ExampleSplitN() {
+	fmt.Printf("%q\n", bytes.SplitN([]byte("a,b,c"), []byte(","), 2))
+	z := bytes.SplitN([]byte("a,b,c"), []byte(","), 0)
+	fmt.Printf("%q (nil = %v)\n", z, z == nil)
+	// Output:
+	// ["a" "b,c"]
+	// [] (nil = true)
+}
+
+func ExampleSplitAfter() {
+	fmt.Printf("%q\n", bytes.SplitAfter([]byte("a,b,c"), []byte(",")))
+	// Output: ["a," "b," "c"]
+}
+
+func ExampleSplitAfterN() {
+	fmt.Printf("%q\n", bytes.SplitAfterN([]byte("a,b,c"), []byte(","), 2))
+	// Output: ["a," "b,c"]
+}
+
+func ExampleTitle() {
+	fmt.Printf("%s", bytes.Title([]byte("her royal highness")))
+	// Output: Her Royal Highness
+}
+
+func ExampleToTitle() {
+	fmt.Printf("%s\n", bytes.ToTitle([]byte("loud noises")))
+	fmt.Printf("%s\n", bytes.ToTitle([]byte("хлеб")))
+	// Output:
+	// LOUD NOISES
+	// ХЛЕБ
+}
+
+func ExampleTrim() {
+	fmt.Printf("[%q]", bytes.Trim([]byte(" !!! Achtung! Achtung! !!! "), "! "))
+	// Output: ["Achtung! Achtung"]
+}
+
+func ExampleMap() {
+	rot13 := func(r rune) rune {
+		switch {
+		case r >= 'A' && r <= 'Z':
+			return 'A' + (r-'A'+13)%26
+		case r >= 'a' && r <= 'z':
+			return 'a' + (r-'a'+13)%26
+		}
+		return r
+	}
+	fmt.Printf("%s", bytes.Map(rot13, []byte("'Twas brillig and the slithy gopher...")))
+	// Output: 'Gjnf oevyyvt naq gur fyvgul tbcure...
+}
+
+func ExampleTrimSpace() {
+	fmt.Printf("%s", bytes.TrimSpace([]byte(" \t\n a lone gopher \n\t\r\n")))
+	// Output: a lone gopher
+}
+
+func ExampleToUpper() {
+	fmt.Printf("%s", bytes.ToUpper([]byte("Gopher")))
+	// Output: GOPHER
+}
+
+func ExampleToLower() {
+	fmt.Printf("%s", bytes.ToLower([]byte("Gopher")))
+	// Output: gopher
+}