libgo: Merge from revision 18783:00cce3a34d7e of master library.

This revision was committed January 7, 2014.  The next
revision deleted runtime/mfinal.c.  That will be done in a
subsequent merge.

This merge changes type descriptors to add a zero field,
pointing to a zero value for that type.  This is implemented
as a common variable.

	* go-gcc.cc (Gcc_backend::implicit_variable): Add is_common and
	alignment parameters.  Permit init parameter to be NULL.

From-SVN: r211249

3 files changed, 31 insertions, 26 deletions

diff --git a/libgo/go/io/io_test.go b/libgo/go/io/io_test.go
index bd7a82f..57db1fb 100644
--- a/libgo/go/io/io_test.go
+++ b/libgo/go/io/io_test.go
@@ -281,6 +281,8 @@ func TestSectionReader_ReadAt(t *testing.T) {
 		{data: dat, off: 3, n: len(dat), bufLen: len(dat) / 2, at: 2, exp: dat[5 : 5+len(dat)/2], err: nil},
 		{data: dat, off: 3, n: len(dat) / 2, bufLen: len(dat)/2 - 2, at: 2, exp: dat[5 : 5+len(dat)/2-2], err: nil},
 		{data: dat, off: 3, n: len(dat) / 2, bufLen: len(dat)/2 + 2, at: 2, exp: dat[5 : 5+len(dat)/2-2], err: EOF},
+		{data: dat, off: 0, n: 0, bufLen: 0, at: -1, exp: "", err: EOF},
+		{data: dat, off: 0, n: 0, bufLen: 0, at: 1, exp: "", err: EOF},
 	}
 	for i, tt := range tests {
 		r := strings.NewReader(tt.data)
@@ -319,3 +321,21 @@ func TestSectionReader_Seek(t *testing.T) {
 		t.Errorf("Read = %v, %v; want 0, EOF", n, err)
 	}
 }
+
+func TestSectionReader_Size(t *testing.T) {
+	tests := []struct {
+		data string
+		want int64
+	}{
+		{"a long sample data, 1234567890", 30},
+		{"", 0},
+	}
+
+	for _, tt := range tests {
+		r := strings.NewReader(tt.data)
+		sr := NewSectionReader(r, 0, int64(len(tt.data)))
+		if got := sr.Size(); got != tt.want {
+			t.Errorf("Size = %v; want %v", got, tt.want)
+		}
+	}
+}
diff --git a/libgo/go/io/ioutil/blackhole.go b/libgo/go/io/ioutil/blackhole.go
deleted file mode 100644
index 101d2c1..0000000
--- a/libgo/go/io/ioutil/blackhole.go
+++ /dev/null
@@ -1,23 +0,0 @@
-// Copyright 2012 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.
-
-package ioutil
-
-var blackHoleBuf = make(chan []byte, 1)
-
-func blackHole() []byte {
-	select {
-	case b := <-blackHoleBuf:
-		return b
-	default:
-	}
-	return make([]byte, 8192)
-}
-
-func blackHolePut(p []byte) {
-	select {
-	case blackHoleBuf <- p:
-	default:
-	}
-}
diff --git a/libgo/go/io/ioutil/ioutil.go b/libgo/go/io/ioutil/ioutil.go
index b2508b7..909a815 100644
--- a/libgo/go/io/ioutil/ioutil.go
+++ b/libgo/go/io/ioutil/ioutil.go
@@ -10,6 +10,7 @@ import (
 	"io"
 	"os"
 	"sort"
+	"sync"
 )
 
 // readAll reads from r until an error or EOF and returns the data it read
@@ -136,14 +137,21 @@ func (devNull) WriteString(s string) (int, error) {
 	return len(s), nil
 }
 
+var blackHolePool = sync.Pool{
+	New: func() interface{} {
+		b := make([]byte, 8192)
+		return &b
+	},
+}
+
 func (devNull) ReadFrom(r io.Reader) (n int64, err error) {
-	buf := blackHole()
-	defer blackHolePut(buf)
+	bufp := blackHolePool.Get().(*[]byte)
 	readSize := 0
 	for {
-		readSize, err = r.Read(buf)
+		readSize, err = r.Read(*bufp)
 		n += int64(readSize)
 		if err != nil {
+			blackHolePool.Put(bufp)
 			if err == io.EOF {
 				return n, nil
 			}