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

3 files changed, 37 insertions, 14 deletions

diff --git a/libgo/go/bufio/bufio.go b/libgo/go/bufio/bufio.go
index 3b30b8b80cd..e1e8fb22720 100644
--- a/libgo/go/bufio/bufio.go
+++ b/libgo/go/bufio/bufio.go
@@ -206,10 +206,18 @@ func (b *Reader) Read(p []byte) (n int, err error) {
 			}
 			return n, b.readErr()
 		}
-		b.fill() // buffer is empty
-		if b.r == b.w {
+		// One read.
+		// Do not use b.fill, which will loop.
+		b.r = 0
+		b.w = 0
+		n, b.err = b.rd.Read(b.buf)
+		if n < 0 {
+			panic(errNegativeRead)
+		}
+		if n == 0 {
 			return 0, b.readErr()
 		}
+		b.w += n
 	}
 
 	// copy as much as we can
@@ -549,11 +557,6 @@ func (b *Writer) Reset(w io.Writer) {
 
 // Flush writes any buffered data to the underlying io.Writer.
 func (b *Writer) Flush() error {
-	err := b.flush()
-	return err
-}
-
-func (b *Writer) flush() error {
 	if b.err != nil {
 		return b.err
 	}
@@ -596,7 +599,7 @@ func (b *Writer) Write(p []byte) (nn int, err error) {
 		} else {
 			n = copy(b.buf[b.n:], p)
 			b.n += n
-			b.flush()
+			b.Flush()
 		}
 		nn += n
 		p = p[n:]
@@ -615,7 +618,7 @@ func (b *Writer) WriteByte(c byte) error {
 	if b.err != nil {
 		return b.err
 	}
-	if b.Available() <= 0 && b.flush() != nil {
+	if b.Available() <= 0 && b.Flush() != nil {
 		return b.err
 	}
 	b.buf[b.n] = c
@@ -638,7 +641,7 @@ func (b *Writer) WriteRune(r rune) (size int, err error) {
 	}
 	n := b.Available()
 	if n < utf8.UTFMax {
-		if b.flush(); b.err != nil {
+		if b.Flush(); b.err != nil {
 			return 0, b.err
 		}
 		n = b.Available()
@@ -663,7 +666,7 @@ func (b *Writer) WriteString(s string) (int, error) {
 		b.n += n
 		nn += n
 		s = s[n:]
-		b.flush()
+		b.Flush()
 	}
 	if b.err != nil {
 		return nn, b.err
@@ -684,7 +687,7 @@ func (b *Writer) ReadFrom(r io.Reader) (n int64, err error) {
 	var m int
 	for {
 		if b.Available() == 0 {
-			if err1 := b.flush(); err1 != nil {
+			if err1 := b.Flush(); err1 != nil {
 				return n, err1
 			}
 		}
@@ -708,7 +711,7 @@ func (b *Writer) ReadFrom(r io.Reader) (n int64, err error) {
 	if err == io.EOF {
 		// If we filled the buffer exactly, flush preemptively.
 		if b.Available() == 0 {
-			err = b.flush()
+			err = b.Flush()
 		} else {
 			err = nil
 		}
diff --git a/libgo/go/bufio/bufio_test.go b/libgo/go/bufio/bufio_test.go
index 858048696e4..ef0f6c834e8 100644
--- a/libgo/go/bufio/bufio_test.go
+++ b/libgo/go/bufio/bufio_test.go
@@ -1236,6 +1236,27 @@ func TestWriterReadFromErrNoProgress(t *testing.T) {
 	}
 }
 
+func TestReadZero(t *testing.T) {
+	for _, size := range []int{100, 2} {
+		t.Run(fmt.Sprintf("bufsize=%d", size), func(t *testing.T) {
+			r := io.MultiReader(strings.NewReader("abc"), &emptyThenNonEmptyReader{r: strings.NewReader("def"), n: 1})
+			br := NewReaderSize(r, size)
+			want := func(s string, wantErr error) {
+				p := make([]byte, 50)
+				n, err := br.Read(p)
+				if err != wantErr || n != len(s) || string(p[:n]) != s {
+					t.Fatalf("read(%d) = %q, %v, want %q, %v", len(p), string(p[:n]), err, s, wantErr)
+				}
+				t.Logf("read(%d) = %q, %v", len(p), string(p[:n]), err)
+			}
+			want("abc", nil)
+			want("", nil)
+			want("def", nil)
+			want("", io.EOF)
+		})
+	}
+}
+
 func TestReaderReset(t *testing.T) {
 	r := NewReader(strings.NewReader("foo foo"))
 	buf := make([]byte, 3)
diff --git a/libgo/go/bufio/scan.go b/libgo/go/bufio/scan.go
index 27a0f004595..9f741c98307 100644
--- a/libgo/go/bufio/scan.go
+++ b/libgo/go/bufio/scan.go
@@ -199,7 +199,6 @@ func (s *Scanner) Scan() bool {
 			s.buf = newBuf
 			s.end -= s.start
 			s.start = 0
-			continue
 		}
 		// Finally we can read some input. Make sure we don't get stuck with
 		// a misbehaving Reader. Officially we don't need to do this, but let's