libgo: update to Go 1.11

    
    Reviewed-on: https://go-review.googlesource.com/136435

gotools/:
	* Makefile.am (mostlyclean-local): Run chmod on check-go-dir to
	make sure it is writable.
	(check-go-tools): Likewise.
	(check-vet): Copy internal/objabi to check-vet-dir.
	* Makefile.in: Rebuild.

From-SVN: r264546

11 files changed, 256 insertions, 296 deletions

diff --git a/libgo/go/strings/builder_test.go b/libgo/go/strings/builder_test.go
index ad012bb..da6c021 100644
--- a/libgo/go/strings/builder_test.go
+++ b/libgo/go/strings/builder_test.go
@@ -85,16 +85,25 @@ func TestBuilderReset(t *testing.T) {
 }
 
 func TestBuilderGrow(t *testing.T) {
+	if runtime.Compiler == "gccgo" {
+		t.Skip("skip for gccgo until escape analysis improves")
+	}
 	for _, growLen := range []int{0, 100, 1000, 10000, 100000} {
-		var b Builder
-		b.Grow(growLen)
 		p := bytes.Repeat([]byte{'a'}, growLen)
-		allocs := numAllocs(func() { b.Write(p) })
-		if allocs > 0 {
-			t.Errorf("growLen=%d: allocation occurred during write", growLen)
+		allocs := testing.AllocsPerRun(100, func() {
+			var b Builder
+			b.Grow(growLen) // should be only alloc, when growLen > 0
+			b.Write(p)
+			if b.String() != string(p) {
+				t.Fatalf("growLen=%d: bad data written after Grow", growLen)
+			}
+		})
+		wantAllocs := 1
+		if growLen == 0 {
+			wantAllocs = 0
 		}
-		if b.String() != string(p) {
-			t.Errorf("growLen=%d: bad data written after Grow", growLen)
+		if g, w := int(allocs), wantAllocs; g != w {
+			t.Errorf("growLen=%d: got %d allocs during Write; want %v", growLen, g, w)
 		}
 	}
 }
@@ -168,16 +177,17 @@ func TestBuilderWriteByte(t *testing.T) {
 
 func TestBuilderAllocs(t *testing.T) {
 	if runtime.Compiler == "gccgo" {
-		t.Skip("skip for gccgo until escape analysis enabled by default")
+		t.Skip("skip for gccgo until escape analysis improves")
 	}
 	var b Builder
-	b.Grow(5)
+	const msg = "hello"
+	b.Grow(len(msg) * 2) // because AllocsPerRun does an extra "warm-up" iteration
 	var s string
-	allocs := numAllocs(func() {
+	allocs := int(testing.AllocsPerRun(1, func() {
 		b.WriteString("hello")
 		s = b.String()
-	})
-	if want := "hello"; s != want {
+	}))
+	if want := msg + msg; s != want {
 		t.Errorf("String: got %#q; want %#q", s, want)
 	}
 	if allocs > 0 {
@@ -197,15 +207,6 @@ func TestBuilderAllocs(t *testing.T) {
 	}
 }
 
-func numAllocs(fn func()) uint64 {
-	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(1))
-	var m1, m2 runtime.MemStats
-	runtime.ReadMemStats(&m1)
-	fn()
-	runtime.ReadMemStats(&m2)
-	return m2.Mallocs - m1.Mallocs
-}
-
 func TestBuilderCopyPanic(t *testing.T) {
 	tests := []struct {
 		name      string
@@ -305,3 +306,52 @@ func TestBuilderCopyPanic(t *testing.T) {
 		}
 	}
 }
+
+var someBytes = []byte("some bytes sdljlk jsklj3lkjlk djlkjw")
+
+var sinkS string
+
+func benchmarkBuilder(b *testing.B, f func(b *testing.B, numWrite int, grow bool)) {
+	b.Run("1Write_NoGrow", func(b *testing.B) {
+		b.ReportAllocs()
+		f(b, 1, false)
+	})
+	b.Run("3Write_NoGrow", func(b *testing.B) {
+		b.ReportAllocs()
+		f(b, 3, false)
+	})
+	b.Run("3Write_Grow", func(b *testing.B) {
+		b.ReportAllocs()
+		f(b, 3, true)
+	})
+}
+
+func BenchmarkBuildString_Builder(b *testing.B) {
+	benchmarkBuilder(b, func(b *testing.B, numWrite int, grow bool) {
+		for i := 0; i < b.N; i++ {
+			var buf Builder
+			if grow {
+				buf.Grow(len(someBytes) * numWrite)
+			}
+			for i := 0; i < numWrite; i++ {
+				buf.Write(someBytes)
+			}
+			sinkS = buf.String()
+		}
+	})
+}
+
+func BenchmarkBuildString_ByteBuffer(b *testing.B) {
+	benchmarkBuilder(b, func(b *testing.B, numWrite int, grow bool) {
+		for i := 0; i < b.N; i++ {
+			var buf bytes.Buffer
+			if grow {
+				buf.Grow(len(someBytes) * numWrite)
+			}
+			for i := 0; i < numWrite; i++ {
+				buf.Write(someBytes)
+			}
+			sinkS = buf.String()
+		}
+	})
+}
diff --git a/libgo/go/strings/compare_test.go b/libgo/go/strings/compare_test.go
index bc12e42..5d53344 100644
--- a/libgo/go/strings/compare_test.go
+++ b/libgo/go/strings/compare_test.go
@@ -8,6 +8,7 @@ package strings_test
 // Benchmarks omitted since the underlying implementation is identical.
 
 import (
+	"internal/testenv"
 	. "strings"
 	"testing"
 )
@@ -52,10 +53,21 @@ func TestCompareIdenticalString(t *testing.T) {
 }
 
 func TestCompareStrings(t *testing.T) {
-	n := 128
+	lengths := make([]int, 0) // lengths to test in ascending order
+	for i := 0; i <= 128; i++ {
+		lengths = append(lengths, i)
+	}
+	lengths = append(lengths, 256, 512, 1024, 1333, 4095, 4096, 4097)
+
+	if !testing.Short() || testenv.Builder() != "" {
+		lengths = append(lengths, 65535, 65536, 65537, 99999)
+	}
+
+	n := lengths[len(lengths)-1]
 	a := make([]byte, n+1)
 	b := make([]byte, n+1)
-	for len := 0; len < 128; len++ {
+	lastLen := 0
+	for _, len := range lengths {
 		// randomish but deterministic data. No 0 or 255.
 		for i := 0; i < len; i++ {
 			a[i] = byte(1 + 31*i%254)
@@ -67,21 +79,22 @@ func TestCompareStrings(t *testing.T) {
 			b[i] = 9
 		}
 
-		cmp := Compare(string(a[:len]), string(b[:len]))
+		sa, sb := string(a), string(b)
+		cmp := Compare(sa[:len], sb[:len])
 		if cmp != 0 {
 			t.Errorf(`CompareIdentical(%d) = %d`, len, cmp)
 		}
 		if len > 0 {
-			cmp = Compare(string(a[:len-1]), string(b[:len]))
+			cmp = Compare(sa[:len-1], sb[:len])
 			if cmp != -1 {
 				t.Errorf(`CompareAshorter(%d) = %d`, len, cmp)
 			}
-			cmp = Compare(string(a[:len]), string(b[:len-1]))
+			cmp = Compare(sa[:len], sb[:len-1])
 			if cmp != 1 {
 				t.Errorf(`CompareBshorter(%d) = %d`, len, cmp)
 			}
 		}
-		for k := 0; k < len; k++ {
+		for k := lastLen; k < len; k++ {
 			b[k] = a[k] - 1
 			cmp = Compare(string(a[:len]), string(b[:len]))
 			if cmp != 1 {
@@ -94,5 +107,6 @@ func TestCompareStrings(t *testing.T) {
 			}
 			b[k] = a[k]
 		}
+		lastLen = len
 	}
 }
diff --git a/libgo/go/strings/replace.go b/libgo/go/strings/replace.go
index 4752641..58a11a6 100644
--- a/libgo/go/strings/replace.go
+++ b/libgo/go/strings/replace.go
@@ -18,8 +18,9 @@ type replacer interface {
 	WriteString(w io.Writer, s string) (n int, err error)
 }
 
-// NewReplacer returns a new Replacer from a list of old, new string pairs.
-// Replacements are performed in order, without overlapping matches.
+// NewReplacer returns a new Replacer from a list of old, new string
+// pairs. Replacements are performed in the order they appear in the
+// target string, without overlapping matches.
 func NewReplacer(oldnew ...string) *Replacer {
 	if len(oldnew)%2 == 1 {
 		panic("strings.NewReplacer: odd argument count")
@@ -54,13 +55,21 @@ func NewReplacer(oldnew ...string) *Replacer {
 		return &Replacer{r: &r}
 	}
 
-	r := byteStringReplacer{}
+	r := byteStringReplacer{toReplace: make([]string, 0, len(oldnew)/2)}
 	// The first occurrence of old->new map takes precedence
 	// over the others with the same old string.
 	for i := len(oldnew) - 2; i >= 0; i -= 2 {
 		o := oldnew[i][0]
 		n := oldnew[i+1]
-		r[o] = []byte(n)
+		// To avoid counting repetitions multiple times.
+		if r.replacements[o] == nil {
+			// We need to use string([]byte{o}) instead of string(o),
+			// to avoid utf8 encoding of o.
+			// E. g. byte(150) produces string of length 2.
+			r.toReplace = append(r.toReplace, string([]byte{o}))
+		}
+		r.replacements[o] = []byte(n)
+
 	}
 	return &Replacer{r: &r}
 }
@@ -454,34 +463,60 @@ func (r *byteReplacer) WriteString(w io.Writer, s string) (n int, err error) {
 
 // byteStringReplacer is the implementation that's used when all the
 // "old" values are single ASCII bytes but the "new" values vary in size.
-// The array contains replacement byte slices indexed by old byte.
-// A nil []byte means that the old byte should not be replaced.
-type byteStringReplacer [256][]byte
+type byteStringReplacer struct {
+	// replacements contains replacement byte slices indexed by old byte.
+	// A nil []byte means that the old byte should not be replaced.
+	replacements [256][]byte
+	// toReplace keeps a list of bytes to replace. Depending on length of toReplace
+	// and length of target string it may be faster to use Count, or a plain loop.
+	// We store single byte as a string, because Count takes a string.
+	toReplace []string
+}
+
+// countCutOff controls the ratio of a string length to a number of replacements
+// at which (*byteStringReplacer).Replace switches algorithms.
+// For strings with higher ration of length to replacements than that value,
+// we call Count, for each replacement from toReplace.
+// For strings, with a lower ratio we use simple loop, because of Count overhead.
+// countCutOff is an empirically determined overhead multiplier.
+// TODO(tocarip) revisit once we have register-based abi/mid-stack inlining.
+const countCutOff = 8
 
 func (r *byteStringReplacer) Replace(s string) string {
 	newSize := len(s)
 	anyChanges := false
-	for i := 0; i < len(s); i++ {
-		b := s[i]
-		if r[b] != nil {
-			anyChanges = true
-			// The -1 is because we are replacing 1 byte with len(r[b]) bytes.
-			newSize += len(r[b]) - 1
+	// Is it faster to use Count?
+	if len(r.toReplace)*countCutOff <= len(s) {
+		for _, x := range r.toReplace {
+			if c := Count(s, x); c != 0 {
+				// The -1 is because we are replacing 1 byte with len(replacements[b]) bytes.
+				newSize += c * (len(r.replacements[x[0]]) - 1)
+				anyChanges = true
+			}
+
+		}
+	} else {
+		for i := 0; i < len(s); i++ {
+			b := s[i]
+			if r.replacements[b] != nil {
+				// See above for explanation of -1
+				newSize += len(r.replacements[b]) - 1
+				anyChanges = true
+			}
 		}
 	}
 	if !anyChanges {
 		return s
 	}
 	buf := make([]byte, newSize)
-	bi := buf
+	j := 0
 	for i := 0; i < len(s); i++ {
 		b := s[i]
-		if r[b] != nil {
-			n := copy(bi, r[b])
-			bi = bi[n:]
+		if r.replacements[b] != nil {
+			j += copy(buf[j:], r.replacements[b])
 		} else {
-			bi[0] = b
-			bi = bi[1:]
+			buf[j] = b
+			j++
 		}
 	}
 	return string(buf)
@@ -492,7 +527,7 @@ func (r *byteStringReplacer) WriteString(w io.Writer, s string) (n int, err erro
 	last := 0
 	for i := 0; i < len(s); i++ {
 		b := s[i]
-		if r[b] == nil {
+		if r.replacements[b] == nil {
 			continue
 		}
 		if last != i {
@@ -503,7 +538,7 @@ func (r *byteStringReplacer) WriteString(w io.Writer, s string) (n int, err erro
 			}
 		}
 		last = i + 1
-		nw, err := w.Write(r[b])
+		nw, err := w.Write(r.replacements[b])
 		n += nw
 		if err != nil {
 			return n, err
diff --git a/libgo/go/strings/search.go b/libgo/go/strings/search.go
index f77c879..e5bffbb 100644
--- a/libgo/go/strings/search.go
+++ b/libgo/go/strings/search.go
@@ -6,8 +6,8 @@ package strings
 
 // stringFinder efficiently finds strings in a source text. It's implemented
 // using the Boyer-Moore string search algorithm:
-// http://en.wikipedia.org/wiki/Boyer-Moore_string_search_algorithm
-// http://www.cs.utexas.edu/~moore/publications/fstrpos.pdf (note: this aged
+// https://en.wikipedia.org/wiki/Boyer-Moore_string_search_algorithm
+// https://www.cs.utexas.edu/~moore/publications/fstrpos.pdf (note: this aged
 // document uses 1-based indexing)
 type stringFinder struct {
 	// pattern is the string that we are searching for in the text.
diff --git a/libgo/go/strings/search_test.go b/libgo/go/strings/search_test.go
index 966c05e..c01a393 100644
--- a/libgo/go/strings/search_test.go
+++ b/libgo/go/strings/search_test.go
@@ -57,7 +57,7 @@ func TestFinderCreation(t *testing.T) {
 			[256]int{'i': 3, 'm': 7, 's': 1},
 			[]int{15, 14, 13, 7, 11, 10, 7, 1},
 		},
-		// From http://www.cs.utexas.edu/~moore/publications/fstrpos.pdf
+		// From https://www.cs.utexas.edu/~moore/publications/fstrpos.pdf
 		{
 			"abcxxxabc",
 			[256]int{'a': 2, 'b': 1, 'c': 6, 'x': 3},
diff --git a/libgo/go/strings/strings.go b/libgo/go/strings/strings.go
index 05e8243..20868be 100644
--- a/libgo/go/strings/strings.go
+++ b/libgo/go/strings/strings.go
@@ -8,6 +8,7 @@
 package strings
 
 import (
+	"internal/bytealg"
 	"unicode"
 	"unicode/utf8"
 )
@@ -72,12 +73,16 @@ func hashStrRev(sep string) (uint32, uint32) {
 	return hash, pow
 }
 
-// countGeneric implements Count.
-func countGeneric(s, substr string) int {
+// Count counts the number of non-overlapping instances of substr in s.
+// If substr is an empty string, Count returns 1 + the number of Unicode code points in s.
+func Count(s, substr string) int {
 	// special case
 	if len(substr) == 0 {
 		return utf8.RuneCountInString(s) + 1
 	}
+	if len(substr) == 1 {
+		return bytealg.CountString(s, substr[0])
+	}
 	n := 0
 	for {
 		i := Index(s, substr)
@@ -792,6 +797,8 @@ func Trim(s string, cutset string) string {
 
 // TrimLeft returns a slice of the string s with all leading
 // Unicode code points contained in cutset removed.
+//
+// To remove a prefix, use TrimPrefix instead.
 func TrimLeft(s string, cutset string) string {
 	if s == "" || cutset == "" {
 		return s
@@ -801,6 +808,8 @@ func TrimLeft(s string, cutset string) string {
 
 // TrimRight returns a slice of the string s, with all trailing
 // Unicode code points contained in cutset removed.
+//
+// To remove a suffix, use TrimSuffix instead.
 func TrimRight(s string, cutset string) string {
 	if s == "" || cutset == "" {
 		return s
@@ -903,9 +912,9 @@ func EqualFold(s, t string) bool {
 			tr, sr = sr, tr
 		}
 		// Fast check for ASCII.
-		if tr < utf8.RuneSelf && 'A' <= sr && sr <= 'Z' {
-			// ASCII, and sr is upper case.  tr must be lower case.
-			if tr == sr+'a'-'A' {
+		if tr < utf8.RuneSelf {
+			// ASCII only, sr/tr must be upper/lower case
+			if 'A' <= sr && sr <= 'Z' && tr == sr+'a'-'A' {
 				continue
 			}
 			return false
@@ -927,6 +936,85 @@ func EqualFold(s, t string) bool {
 	return s == t
 }
 
+// Index returns the index of the first instance of substr in s, or -1 if substr is not present in s.
+func Index(s, substr string) int {
+	n := len(substr)
+	switch {
+	case n == 0:
+		return 0
+	case n == 1:
+		return IndexByte(s, substr[0])
+	case n == len(s):
+		if substr == s {
+			return 0
+		}
+		return -1
+	case n > len(s):
+		return -1
+	case n <= bytealg.MaxLen:
+		// Use brute force when s and substr both are small
+		if len(s) <= bytealg.MaxBruteForce {
+			return bytealg.IndexString(s, substr)
+		}
+		c := substr[0]
+		i := 0
+		t := s[:len(s)-n+1]
+		fails := 0
+		for i < len(t) {
+			if t[i] != c {
+				// IndexByte is faster than bytealg.IndexString, so use it as long as
+				// we're not getting lots of false positives.
+				o := IndexByte(t[i:], c)
+				if o < 0 {
+					return -1
+				}
+				i += o
+			}
+			if s[i:i+n] == substr {
+				return i
+			}
+			fails++
+			i++
+			// Switch to bytealg.IndexString when IndexByte produces too many false positives.
+			if fails > bytealg.Cutover(i) {
+				r := bytealg.IndexString(s[i:], substr)
+				if r >= 0 {
+					return r + i
+				}
+				return -1
+			}
+		}
+		return -1
+	}
+	c := substr[0]
+	i := 0
+	t := s[:len(s)-n+1]
+	fails := 0
+	for i < len(t) {
+		if t[i] != c {
+			o := IndexByte(t[i:], c)
+			if o < 0 {
+				return -1
+			}
+			i += o
+		}
+		if s[i:i+n] == substr {
+			return i
+		}
+		i++
+		fails++
+		if fails >= 4+i>>4 && i < len(t) {
+			// See comment in ../bytes/bytes_generic.go.
+			j := indexRabinKarp(s[i:], substr)
+			if j < 0 {
+				return -1
+			}
+			return i + j
+		}
+	}
+	return -1
+}
+
 func indexRabinKarp(s, substr string) int {
 	// Rabin-Karp search
 	hashss, pow := hashStr(substr)
diff --git a/libgo/go/strings/strings_amd64.go b/libgo/go/strings/strings_amd64.go
deleted file mode 100644
index 2441569..0000000
--- a/libgo/go/strings/strings_amd64.go
+++ /dev/null
@@ -1,90 +0,0 @@
-// 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 ignore
-
-package strings
-
-import "internal/cpu"
-
-//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 string) int  // ../runtime/asm_amd64.s
-func countByte(s string, c byte) int // ../runtime/asm_amd64.s
-
-var shortStringLen int
-
-func init() {
-	if cpu.X86.HasAVX2 {
-		shortStringLen = 63
-	} else {
-		shortStringLen = 31
-	}
-}
-
-// Index returns the index of the first instance of substr in s, or -1 if substr is not present in s.
-func Index(s, substr string) int {
-	n := len(substr)
-	switch {
-	case n == 0:
-		return 0
-	case n == 1:
-		return IndexByte(s, substr[0])
-	case n == len(s):
-		if substr == s {
-			return 0
-		}
-		return -1
-	case n > len(s):
-		return -1
-	case n <= shortStringLen:
-		// Use brute force when s and substr both are small
-		if len(s) <= 64 {
-			return indexShortStr(s, substr)
-		}
-		c := substr[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 s[i:i+n] == substr {
-				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:], substr)
-				if r >= 0 {
-					return r + i
-				}
-				return -1
-			}
-		}
-		return -1
-	}
-	return indexRabinKarp(s, substr)
-}
-
-// Count counts the number of non-overlapping instances of substr in s.
-// If substr is an empty string, Count returns 1 + the number of Unicode code points in s.
-func Count(s, substr string) int {
-	if len(substr) == 1 && cpu.X86.HasPOPCNT {
-		return countByte(s, byte(substr[0]))
-	}
-	return countGeneric(s, substr)
-}
diff --git a/libgo/go/strings/strings_decl.go b/libgo/go/strings/strings_decl.go
index 3bae844..9819444 100644
--- a/libgo/go/strings/strings_decl.go
+++ b/libgo/go/strings/strings_decl.go
@@ -5,4 +5,4 @@
 package strings
 
 // IndexByte returns the index of the first instance of c in s, or -1 if c is not present in s.
-func IndexByte(s string, c byte) int // ../runtime/asm_$GOARCH.s
+func IndexByte(s string, c byte) int // in internal/bytealg
diff --git a/libgo/go/strings/strings_generic.go b/libgo/go/strings/strings_generic.go
deleted file mode 100644
index 60a6f78..0000000
--- a/libgo/go/strings/strings_generic.go
+++ /dev/null
@@ -1,61 +0,0 @@
-// 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 strings
-
-// TODO: implements short string optimization on non amd64 platforms
-// and get rid of strings_amd64.go
-
-// Index returns the index of the first instance of substr in s, or -1 if substr is not present in s.
-func Index(s, substr string) int {
-	n := len(substr)
-	switch {
-	case n == 0:
-		return 0
-	case n == 1:
-		return IndexByte(s, substr[0])
-	case n == len(s):
-		if substr == s {
-			return 0
-		}
-		return -1
-	case n > len(s):
-		return -1
-	}
-	c := substr[0]
-	i := 0
-	t := s[:len(s)-n+1]
-	fails := 0
-	for i < len(t) {
-		if t[i] != c {
-			o := IndexByte(t[i:], c)
-			if o < 0 {
-				return -1
-			}
-			i += o
-		}
-		if s[i:i+n] == substr {
-			return i
-		}
-		i++
-		fails++
-		if fails >= 4+i>>4 && i < len(t) {
-			// See comment in ../bytes/bytes_generic.go.
-			j := indexRabinKarp(s[i:], substr)
-			if j < 0 {
-				return -1
-			}
-			return i + j
-		}
-	}
-	return -1
-}
-
-// Count counts the number of non-overlapping instances of substr in s.
-// If substr is an empty string, Count returns 1 + the number of Unicode code points in s.
-func Count(s, substr string) int {
-	return countGeneric(s, substr)
-}
diff --git a/libgo/go/strings/strings_s390x.go b/libgo/go/strings/strings_s390x.go
deleted file mode 100644
index e74e4cd..0000000
--- a/libgo/go/strings/strings_s390x.go
+++ /dev/null
@@ -1,88 +0,0 @@
-// 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 strings
-
-//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, sep string) int // ../runtime/asm_$GOARCH.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 substr in s, or -1 if substr is not present in s.
-func Index(s, substr string) int {
-	n := len(substr)
-	switch {
-	case n == 0:
-		return 0
-	case n == 1:
-		return IndexByte(s, substr[0])
-	case n == len(s):
-		if substr == s {
-			return 0
-		}
-		return -1
-	case n > len(s):
-		return -1
-	case n <= shortStringLen:
-		// Use brute force when s and substr both are small
-		if len(s) <= 64 {
-			return indexShortStr(s, substr)
-		}
-		c := substr[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 s[i:i+n] == substr {
-				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:], substr)
-				if r >= 0 {
-					return r + i
-				}
-				return -1
-			}
-		}
-		return -1
-	}
-	return indexRabinKarp(s, substr)
-}
-
-// Count counts the number of non-overlapping instances of substr in s.
-// If substr is an empty string, Count returns 1 + the number of Unicode code points in s.
-func Count(s, substr string) int {
-	return countGeneric(s, substr)
-}
diff --git a/libgo/go/strings/strings_test.go b/libgo/go/strings/strings_test.go
index 92122db..3f0c790 100644
--- a/libgo/go/strings/strings_test.go
+++ b/libgo/go/strings/strings_test.go
@@ -1406,6 +1406,8 @@ var EqualFoldTests = []struct {
 	{"abcdefghijK", "abcdefghij\u212A", true},
 	{"abcdefghijkz", "abcdefghij\u212Ay", false},
 	{"abcdefghijKz", "abcdefghij\u212Ay", false},
+	{"1", "2", false},
+	{"utf-8", "US-ASCII", false},
 }
 
 func TestEqualFold(t *testing.T) {
@@ -1419,6 +1421,16 @@ func TestEqualFold(t *testing.T) {
 	}
 }
 
+func BenchmarkEqualFold(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, tt := range EqualFoldTests {
+			if out := EqualFold(tt.s, tt.t); out != tt.out {
+				b.Fatal("wrong result")
+			}
+		}
+	}
+}
+
 var CountTests = []struct {
 	s, sep string
 	num    int