libgo: Update to weekly.2012-03-04 release.

From-SVN: r185010

147 files changed, 3079 insertions, 2021 deletions

diff --git a/libgo/MERGE b/libgo/MERGE
index 9605a8a9040..17d01ce7265 100644
--- a/libgo/MERGE
+++ b/libgo/MERGE
@@ -1,4 +1,4 @@
-96bd78e7d35e
+f4470a54e6db
 
 The first line of this file holds the Mercurial revision number of the
 last merge done from the master library sources.
diff --git a/libgo/Makefile.am b/libgo/Makefile.am
index eb764df0eab..d43f0542938 100644
--- a/libgo/Makefile.am
+++ b/libgo/Makefile.am
@@ -658,10 +658,17 @@ go_net_sock_file = go/net/sock_linux.go
 go_net_sockopt_file = go/net/sockopt_linux.go
 go_net_sockoptip_file = go/net/sockoptip_linux.go
 else
+if LIBGO_IS_FREEBSD
 go_net_cgo_file = go/net/cgo_bsd.go
 go_net_sock_file = go/net/sock_bsd.go
 go_net_sockopt_file = go/net/sockopt_bsd.go
-go_net_sockoptip_file = go/net/sockoptip_bsd.go
+go_net_sockoptip_file = go/net/sockoptip_bsd.go go/net/sockoptip_freebsd.go
+else
+go_net_cgo_file = go/net/cgo_bsd.go
+go_net_sock_file = go/net/sock_bsd.go
+go_net_sockopt_file = go/net/sockopt_bsd.go
+go_net_sockoptip_file = go/net/sockoptip_bsd.go go/net/sockoptip_netbsd.go
+endif
 endif
 endif
 endif
@@ -704,6 +711,7 @@ go_net_files = \
 	go/net/ipsock.go \
 	go/net/ipsock_posix.go \
 	go/net/lookup_unix.go \
+	go/net/mac.go \
 	go/net/net.go \
 	go/net/parse.go \
 	go/net/pipe.go \
@@ -1126,8 +1134,7 @@ go_go_ast_files = \
 	go/go/ast/walk.go
 go_go_build_files = \
 	go/go/build/build.go \
-	go/go/build/dir.go \
-	go/go/build/path.go \
+	go/go/build/doc.go \
 	syslist.go
 go_go_doc_files = \
 	go/go/doc/comment.go \
diff --git a/libgo/Makefile.in b/libgo/Makefile.in
index 4604e560c9b..418c7876a31 100644
--- a/libgo/Makefile.in
+++ b/libgo/Makefile.in
@@ -1012,19 +1012,23 @@ go_mime_files = \
 @LIBGO_IS_LINUX_FALSE@@LIBGO_IS_NETBSD_TRUE@@LIBGO_IS_RTEMS_FALSE@go_net_newpollserver_file = go/net/newpollserver.go
 @LIBGO_IS_LINUX_TRUE@@LIBGO_IS_RTEMS_FALSE@go_net_newpollserver_file = go/net/newpollserver.go
 @LIBGO_IS_RTEMS_TRUE@go_net_newpollserver_file = go/net/newpollserver_rtems.go
-@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_cgo_file = go/net/cgo_bsd.go
+@LIBGO_IS_FREEBSD_FALSE@@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_cgo_file = go/net/cgo_bsd.go
+@LIBGO_IS_FREEBSD_TRUE@@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_cgo_file = go/net/cgo_bsd.go
 @LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_TRUE@go_net_cgo_file = go/net/cgo_linux.go
 @LIBGO_IS_IRIX_TRUE@@LIBGO_IS_LINUX_FALSE@go_net_cgo_file = go/net/cgo_linux.go
 @LIBGO_IS_LINUX_TRUE@go_net_cgo_file = go/net/cgo_linux.go
-@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_sock_file = go/net/sock_bsd.go
+@LIBGO_IS_FREEBSD_FALSE@@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_sock_file = go/net/sock_bsd.go
+@LIBGO_IS_FREEBSD_TRUE@@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_sock_file = go/net/sock_bsd.go
 @LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_TRUE@go_net_sock_file = go/net/sock_linux.go
 @LIBGO_IS_IRIX_TRUE@@LIBGO_IS_LINUX_FALSE@go_net_sock_file = go/net/sock_linux.go
 @LIBGO_IS_LINUX_TRUE@go_net_sock_file = go/net/sock_linux.go
-@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_sockopt_file = go/net/sockopt_bsd.go
+@LIBGO_IS_FREEBSD_FALSE@@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_sockopt_file = go/net/sockopt_bsd.go
+@LIBGO_IS_FREEBSD_TRUE@@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_sockopt_file = go/net/sockopt_bsd.go
 @LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_TRUE@go_net_sockopt_file = go/net/sockopt_linux.go
 @LIBGO_IS_IRIX_TRUE@@LIBGO_IS_LINUX_FALSE@go_net_sockopt_file = go/net/sockopt_linux.go
 @LIBGO_IS_LINUX_TRUE@go_net_sockopt_file = go/net/sockopt_linux.go
-@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_sockoptip_file = go/net/sockoptip_bsd.go
+@LIBGO_IS_FREEBSD_FALSE@@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_sockoptip_file = go/net/sockoptip_bsd.go go/net/sockoptip_netbsd.go
+@LIBGO_IS_FREEBSD_TRUE@@LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_FALSE@go_net_sockoptip_file = go/net/sockoptip_bsd.go go/net/sockoptip_freebsd.go
 @LIBGO_IS_IRIX_FALSE@@LIBGO_IS_LINUX_FALSE@@LIBGO_IS_SOLARIS_TRUE@go_net_sockoptip_file = go/net/sockoptip_linux.go
 @LIBGO_IS_IRIX_TRUE@@LIBGO_IS_LINUX_FALSE@go_net_sockoptip_file = go/net/sockoptip_linux.go
 @LIBGO_IS_LINUX_TRUE@go_net_sockoptip_file = go/net/sockoptip_linux.go
@@ -1055,6 +1059,7 @@ go_net_files = \
 	go/net/ipsock.go \
 	go/net/ipsock_posix.go \
 	go/net/lookup_unix.go \
+	go/net/mac.go \
 	go/net/net.go \
 	go/net/parse.go \
 	go/net/pipe.go \
@@ -1467,8 +1472,7 @@ go_go_ast_files = \
 
 go_go_build_files = \
 	go/go/build/build.go \
-	go/go/build/dir.go \
-	go/go/build/path.go \
+	go/go/build/doc.go \
 	syslist.go
 
 go_go_doc_files = \
diff --git a/libgo/go/archive/zip/reader.go b/libgo/go/archive/zip/reader.go
index c3009869b60..f3826dcc48d 100644
--- a/libgo/go/archive/zip/reader.go
+++ b/libgo/go/archive/zip/reader.go
@@ -169,48 +169,21 @@ func (r *checksumReader) Read(b []byte) (n int, err error) {
 
 func (r *checksumReader) Close() error { return r.rc.Close() }
 
-func readFileHeader(f *File, r io.Reader) error {
-	var b [fileHeaderLen]byte
-	if _, err := io.ReadFull(r, b[:]); err != nil {
-		return err
-	}
-	c := binary.LittleEndian
-	if sig := c.Uint32(b[:4]); sig != fileHeaderSignature {
-		return ErrFormat
-	}
-	f.ReaderVersion = c.Uint16(b[4:6])
-	f.Flags = c.Uint16(b[6:8])
-	f.Method = c.Uint16(b[8:10])
-	f.ModifiedTime = c.Uint16(b[10:12])
-	f.ModifiedDate = c.Uint16(b[12:14])
-	f.CRC32 = c.Uint32(b[14:18])
-	f.CompressedSize = c.Uint32(b[18:22])
-	f.UncompressedSize = c.Uint32(b[22:26])
-	filenameLen := int(c.Uint16(b[26:28]))
-	extraLen := int(c.Uint16(b[28:30]))
-	d := make([]byte, filenameLen+extraLen)
-	if _, err := io.ReadFull(r, d); err != nil {
-		return err
-	}
-	f.Name = string(d[:filenameLen])
-	f.Extra = d[filenameLen:]
-	return nil
-}
-
 // findBodyOffset does the minimum work to verify the file has a header
 // and returns the file body offset.
 func (f *File) findBodyOffset() (int64, error) {
 	r := io.NewSectionReader(f.zipr, f.headerOffset, f.zipsize-f.headerOffset)
-	var b [fileHeaderLen]byte
-	if _, err := io.ReadFull(r, b[:]); err != nil {
+	var buf [fileHeaderLen]byte
+	if _, err := io.ReadFull(r, buf[:]); err != nil {
 		return 0, err
 	}
-	c := binary.LittleEndian
-	if sig := c.Uint32(b[:4]); sig != fileHeaderSignature {
+	b := readBuf(buf[:])
+	if sig := b.uint32(); sig != fileHeaderSignature {
 		return 0, ErrFormat
 	}
-	filenameLen := int(c.Uint16(b[26:28]))
-	extraLen := int(c.Uint16(b[28:30]))
+	b = b[22:] // skip over most of the header
+	filenameLen := int(b.uint16())
+	extraLen := int(b.uint16())
 	return int64(fileHeaderLen + filenameLen + extraLen), nil
 }
 
@@ -218,30 +191,29 @@ func (f *File) findBodyOffset() (int64, error) {
 // It returns io.ErrUnexpectedEOF if it cannot read a complete header,
 // and ErrFormat if it doesn't find a valid header signature.
 func readDirectoryHeader(f *File, r io.Reader) error {
-	var b [directoryHeaderLen]byte
-	if _, err := io.ReadFull(r, b[:]); err != nil {
+	var buf [directoryHeaderLen]byte
+	if _, err := io.ReadFull(r, buf[:]); err != nil {
 		return err
 	}
-	c := binary.LittleEndian
-	if sig := c.Uint32(b[:4]); sig != directoryHeaderSignature {
+	b := readBuf(buf[:])
+	if sig := b.uint32(); sig != directoryHeaderSignature {
 		return ErrFormat
 	}
-	f.CreatorVersion = c.Uint16(b[4:6])
-	f.ReaderVersion = c.Uint16(b[6:8])
-	f.Flags = c.Uint16(b[8:10])
-	f.Method = c.Uint16(b[10:12])
-	f.ModifiedTime = c.Uint16(b[12:14])
-	f.ModifiedDate = c.Uint16(b[14:16])
-	f.CRC32 = c.Uint32(b[16:20])
-	f.CompressedSize = c.Uint32(b[20:24])
-	f.UncompressedSize = c.Uint32(b[24:28])
-	filenameLen := int(c.Uint16(b[28:30]))
-	extraLen := int(c.Uint16(b[30:32]))
-	commentLen := int(c.Uint16(b[32:34]))
-	// startDiskNumber := c.Uint16(b[34:36])    // Unused
-	// internalAttributes := c.Uint16(b[36:38]) // Unused
-	f.ExternalAttrs = c.Uint32(b[38:42])
-	f.headerOffset = int64(c.Uint32(b[42:46]))
+	f.CreatorVersion = b.uint16()
+	f.ReaderVersion = b.uint16()
+	f.Flags = b.uint16()
+	f.Method = b.uint16()
+	f.ModifiedTime = b.uint16()
+	f.ModifiedDate = b.uint16()
+	f.CRC32 = b.uint32()
+	f.CompressedSize = b.uint32()
+	f.UncompressedSize = b.uint32()
+	filenameLen := int(b.uint16())
+	extraLen := int(b.uint16())
+	commentLen := int(b.uint16())
+	b = b[4:] // skipped start disk number and internal attributes (2x uint16)
+	f.ExternalAttrs = b.uint32()
+	f.headerOffset = int64(b.uint32())
 	d := make([]byte, filenameLen+extraLen+commentLen)
 	if _, err := io.ReadFull(r, d); err != nil {
 		return err
@@ -253,30 +225,30 @@ func readDirectoryHeader(f *File, r io.Reader) error {
 }
 
 func readDataDescriptor(r io.Reader, f *File) error {
-	var b [dataDescriptorLen]byte
-	if _, err := io.ReadFull(r, b[:]); err != nil {
+	var buf [dataDescriptorLen]byte
+	if _, err := io.ReadFull(r, buf[:]); err != nil {
 		return err
 	}
-	c := binary.LittleEndian
-	f.CRC32 = c.Uint32(b[:4])
-	f.CompressedSize = c.Uint32(b[4:8])
-	f.UncompressedSize = c.Uint32(b[8:12])
+	b := readBuf(buf[:])
+	f.CRC32 = b.uint32()
+	f.CompressedSize = b.uint32()
+	f.UncompressedSize = b.uint32()
 	return nil
 }
 
 func readDirectoryEnd(r io.ReaderAt, size int64) (dir *directoryEnd, err error) {
 	// look for directoryEndSignature in the last 1k, then in the last 65k
-	var b []byte
+	var buf []byte
 	for i, bLen := range []int64{1024, 65 * 1024} {
 		if bLen > size {
 			bLen = size
 		}
-		b = make([]byte, int(bLen))
-		if _, err := r.ReadAt(b, size-bLen); err != nil && err != io.EOF {
+		buf = make([]byte, int(bLen))
+		if _, err := r.ReadAt(buf, size-bLen); err != nil && err != io.EOF {
 			return nil, err
 		}
-		if p := findSignatureInBlock(b); p >= 0 {
-			b = b[p:]
+		if p := findSignatureInBlock(buf); p >= 0 {
+			buf = buf[p:]
 			break
 		}
 		if i == 1 || bLen == size {
@@ -285,16 +257,21 @@ func readDirectoryEnd(r io.ReaderAt, size int64) (dir *directoryEnd, err error)
 	}
 
 	// read header into struct
-	c := binary.LittleEndian
-	d := new(directoryEnd)
-	d.diskNbr = c.Uint16(b[4:6])
-	d.dirDiskNbr = c.Uint16(b[6:8])
-	d.dirRecordsThisDisk = c.Uint16(b[8:10])
-	d.directoryRecords = c.Uint16(b[10:12])
-	d.directorySize = c.Uint32(b[12:16])
-	d.directoryOffset = c.Uint32(b[16:20])
-	d.commentLen = c.Uint16(b[20:22])
-	d.comment = string(b[22 : 22+int(d.commentLen)])
+	b := readBuf(buf[4:]) // skip signature
+	d := &directoryEnd{
+		diskNbr:            b.uint16(),
+		dirDiskNbr:         b.uint16(),
+		dirRecordsThisDisk: b.uint16(),
+		directoryRecords:   b.uint16(),
+		directorySize:      b.uint32(),
+		directoryOffset:    b.uint32(),
+		commentLen:         b.uint16(),
+	}
+	l := int(d.commentLen)
+	if l > len(b) {
+		return nil, errors.New("zip: invalid comment length")
+	}
+	d.comment = string(b[:l])
 	return d, nil
 }
 
@@ -311,3 +288,17 @@ func findSignatureInBlock(b []byte) int {
 	}
 	return -1
 }
+
+type readBuf []byte
+
+func (b *readBuf) uint16() uint16 {
+	v := binary.LittleEndian.Uint16(*b)
+	*b = (*b)[2:]
+	return v
+}
+
+func (b *readBuf) uint32() uint32 {
+	v := binary.LittleEndian.Uint32(*b)
+	*b = (*b)[4:]
+	return v
+}
diff --git a/libgo/go/archive/zip/reader_test.go b/libgo/go/archive/zip/reader_test.go
index ea9e0020db4..066a61580c5 100644
--- a/libgo/go/archive/zip/reader_test.go
+++ b/libgo/go/archive/zip/reader_test.go
@@ -165,7 +165,7 @@ func readTestZip(t *testing.T, zt ZipTest) {
 		t.Errorf("%s: comment=%q, want %q", zt.Name, z.Comment, zt.Comment)
 	}
 	if len(z.File) != len(zt.File) {
-		t.Errorf("%s: file count=%d, want %d", zt.Name, len(z.File), len(zt.File))
+		t.Fatalf("%s: file count=%d, want %d", zt.Name, len(z.File), len(zt.File))
 	}
 
 	// test read of each file
diff --git a/libgo/go/archive/zip/struct.go b/libgo/go/archive/zip/struct.go
index 35dcec6468b..fdbd16da048 100644
--- a/libgo/go/archive/zip/struct.go
+++ b/libgo/go/archive/zip/struct.go
@@ -100,16 +100,6 @@ type directoryEnd struct {
 	comment            string
 }
 
-func recoverError(errp *error) {
-	if e := recover(); e != nil {
-		if err, ok := e.(error); ok {
-			*errp = err
-			return
-		}
-		panic(e)
-	}
-}
-
 // msDosTimeToTime converts an MS-DOS date and time into a time.Time.
 // The resolution is 2s.
 // See: http://msdn.microsoft.com/en-us/library/ms724247(v=VS.85).aspx
diff --git a/libgo/go/archive/zip/writer.go b/libgo/go/archive/zip/writer.go
index c591aed5ced..b2cc55bc93b 100644
--- a/libgo/go/archive/zip/writer.go
+++ b/libgo/go/archive/zip/writer.go
@@ -37,10 +37,10 @@ func NewWriter(w io.Writer) *Writer {
 
 // Close finishes writing the zip file by writing the central directory.
 // It does not (and can not) close the underlying writer.
-func (w *Writer) Close() (err error) {
+func (w *Writer) Close() error {
 	if w.last != nil && !w.last.closed {
-		if err = w.last.close(); err != nil {
-			return
+		if err := w.last.close(); err != nil {
+			return err
 		}
 		w.last = nil
 	}
@@ -49,43 +49,55 @@ func (w *Writer) Close() (err error) {
 	}
 	w.closed = true
 
-	defer recoverError(&err)
-
 	// write central directory
 	start := w.cw.count
 	for _, h := range w.dir {
-		write(w.cw, uint32(directoryHeaderSignature))
-		write(w.cw, h.CreatorVersion)
-		write(w.cw, h.ReaderVersion)
-		write(w.cw, h.Flags)
-		write(w.cw, h.Method)
-		write(w.cw, h.ModifiedTime)
-		write(w.cw, h.ModifiedDate)
-		write(w.cw, h.CRC32)
-		write(w.cw, h.CompressedSize)
-		write(w.cw, h.UncompressedSize)
-		write(w.cw, uint16(len(h.Name)))
-		write(w.cw, uint16(len(h.Extra)))
-		write(w.cw, uint16(len(h.Comment)))
-		write(w.cw, uint16(0)) // disk number start
-		write(w.cw, uint16(0)) // internal file attributes
-		write(w.cw, h.ExternalAttrs)
-		write(w.cw, h.offset)
-		writeBytes(w.cw, []byte(h.Name))
-		writeBytes(w.cw, h.Extra)
-		writeBytes(w.cw, []byte(h.Comment))
+		var buf [directoryHeaderLen]byte
+		b := writeBuf(buf[:])
+		b.uint32(uint32(directoryHeaderSignature))
+		b.uint16(h.CreatorVersion)
+		b.uint16(h.ReaderVersion)
+		b.uint16(h.Flags)
+		b.uint16(h.Method)
+		b.uint16(h.ModifiedTime)
+		b.uint16(h.ModifiedDate)
+		b.uint32(h.CRC32)
+		b.uint32(h.CompressedSize)
+		b.uint32(h.UncompressedSize)
+		b.uint16(uint16(len(h.Name)))
+		b.uint16(uint16(len(h.Extra)))
+		b.uint16(uint16(len(h.Comment)))
+		b = b[4:] // skip disk number start and internal file attr (2x uint16)
+		b.uint32(h.ExternalAttrs)
+		b.uint32(h.offset)
+		if _, err := w.cw.Write(buf[:]); err != nil {
+			return err
+		}
+		if _, err := io.WriteString(w.cw, h.Name); err != nil {
+			return err
+		}
+		if _, err := w.cw.Write(h.Extra); err != nil {
+			return err
+		}
+		if _, err := io.WriteString(w.cw, h.Comment); err != nil {
+			return err
+		}
 	}
 	end := w.cw.count
 
 	// write end record
-	write(w.cw, uint32(directoryEndSignature))
-	write(w.cw, uint16(0))          // disk number
-	write(w.cw, uint16(0))          // disk number where directory starts
-	write(w.cw, uint16(len(w.dir))) // number of entries this disk
-	write(w.cw, uint16(len(w.dir))) // number of entries total
-	write(w.cw, uint32(end-start))  // size of directory
-	write(w.cw, uint32(start))      // start of directory
-	write(w.cw, uint16(0))          // size of comment
+	var buf [directoryEndLen]byte
+	b := writeBuf(buf[:])
+	b.uint32(uint32(directoryEndSignature))
+	b = b[4:]                     // skip over disk number and first disk number (2x uint16)
+	b.uint16(uint16(len(w.dir)))  // number of entries this disk
+	b.uint16(uint16(len(w.dir)))  // number of entries total
+	b.uint32(uint32(end - start)) // size of directory
+	b.uint32(uint32(start))       // start of directory
+	// skipped size of comment (always zero)
+	if _, err := w.cw.Write(buf[:]); err != nil {
+		return err
+	}
 
 	return w.cw.w.(*bufio.Writer).Flush()
 }
@@ -152,22 +164,28 @@ func (w *Writer) CreateHeader(fh *FileHeader) (io.Writer, error) {
 	return fw, nil
 }
 
-func writeHeader(w io.Writer, h *FileHeader) (err error) {
-	defer recoverError(&err)
-	write(w, uint32(fileHeaderSignature))
-	write(w, h.ReaderVersion)
-	write(w, h.Flags)
-	write(w, h.Method)
-	write(w, h.ModifiedTime)
-	write(w, h.ModifiedDate)
-	write(w, h.CRC32)
-	write(w, h.CompressedSize)
-	write(w, h.UncompressedSize)
-	write(w, uint16(len(h.Name)))
-	write(w, uint16(len(h.Extra)))
-	writeBytes(w, []byte(h.Name))
-	writeBytes(w, h.Extra)
-	return nil
+func writeHeader(w io.Writer, h *FileHeader) error {
+	var buf [fileHeaderLen]byte
+	b := writeBuf(buf[:])
+	b.uint32(uint32(fileHeaderSignature))
+	b.uint16(h.ReaderVersion)
+	b.uint16(h.Flags)
+	b.uint16(h.Method)
+	b.uint16(h.ModifiedTime)
+	b.uint16(h.ModifiedDate)
+	b.uint32(h.CRC32)
+	b.uint32(h.CompressedSize)
+	b.uint32(h.UncompressedSize)
+	b.uint16(uint16(len(h.Name)))
+	b.uint16(uint16(len(h.Extra)))
+	if _, err := w.Write(buf[:]); err != nil {
+		return err
+	}
+	if _, err := io.WriteString(w, h.Name); err != nil {
+		return err
+	}
+	_, err := w.Write(h.Extra)
+	return err
 }
 
 type fileWriter struct {
@@ -188,13 +206,13 @@ func (w *fileWriter) Write(p []byte) (int, error) {
 	return w.rawCount.Write(p)
 }
 
-func (w *fileWriter) close() (err error) {
+func (w *fileWriter) close() error {
 	if w.closed {
 		return errors.New("zip: file closed twice")
 	}
 	w.closed = true
-	if err = w.comp.Close(); err != nil {
-		return
+	if err := w.comp.Close(); err != nil {
+		return err
 	}
 
 	// update FileHeader
@@ -204,12 +222,13 @@ func (w *fileWriter) close() (err error) {
 	fh.UncompressedSize = uint32(w.rawCount.count)
 
 	// write data descriptor
-	defer recoverError(&err)
-	write(w.zipw, fh.CRC32)
-	write(w.zipw, fh.CompressedSize)
-	write(w.zipw, fh.UncompressedSize)
-
-	return nil
+	var buf [dataDescriptorLen]byte
+	b := writeBuf(buf[:])
+	b.uint32(fh.CRC32)
+	b.uint32(fh.CompressedSize)
+	b.uint32(fh.UncompressedSize)
+	_, err := w.zipw.Write(buf[:])
+	return err
 }
 
 type countWriter struct {
@@ -231,18 +250,14 @@ func (w nopCloser) Close() error {
 	return nil
 }
 
-func write(w io.Writer, data interface{}) {
-	if err := binary.Write(w, binary.LittleEndian, data); err != nil {
-		panic(err)
-	}
+type writeBuf []byte
+
+func (b *writeBuf) uint16(v uint16) {
+	binary.LittleEndian.PutUint16(*b, v)
+	*b = (*b)[2:]
 }
 
-func writeBytes(w io.Writer, b []byte) {
-	n, err := w.Write(b)
-	if err != nil {
-		panic(err)
-	}
-	if n != len(b) {
-		panic(io.ErrShortWrite)
-	}
+func (b *writeBuf) uint32(v uint32) {
+	binary.LittleEndian.PutUint32(*b, v)
+	*b = (*b)[4:]
 }
diff --git a/libgo/go/bufio/bufio.go b/libgo/go/bufio/bufio.go
index 6f3b1eec971..b44d0e7d167 100644
--- a/libgo/go/bufio/bufio.go
+++ b/libgo/go/bufio/bufio.go
@@ -23,7 +23,6 @@ var (
 	ErrInvalidUnreadRune = errors.New("bufio: invalid use of UnreadRune")
 	ErrBufferFull        = errors.New("bufio: buffer full")
 	ErrNegativeCount     = errors.New("bufio: negative count")
-	errInternal          = errors.New("bufio: internal error")
 )
 
 // Buffered input.
diff --git a/libgo/go/crypto/ecdsa/ecdsa.go b/libgo/go/crypto/ecdsa/ecdsa.go
index d2f7d8f9bb3..b28239b7862 100644
--- a/libgo/go/crypto/ecdsa/ecdsa.go
+++ b/libgo/go/crypto/ecdsa/ecdsa.go
@@ -7,7 +7,7 @@
 package ecdsa
 
 // References:
-//   [NSA]: Suite B implementor's guide to FIPS 186-3,
+//   [NSA]: Suite B implementer's guide to FIPS 186-3,
 //     http://www.nsa.gov/ia/_files/ecdsa.pdf
 //   [SECG]: SECG, SEC1
 //     http://www.secg.org/download/aid-780/sec1-v2.pdf
diff --git a/libgo/go/crypto/tls/root_darwin.go b/libgo/go/crypto/tls/root_darwin.go
index db1b18b3c07..911a9a62e3c 100644
--- a/libgo/go/crypto/tls/root_darwin.go
+++ b/libgo/go/crypto/tls/root_darwin.go
@@ -5,11 +5,9 @@
 package tls
 
 /*
-// Note: We disable -Werror here because the code in this file uses a deprecated API to stay
-// compatible with both Mac OS X 10.6 and 10.7. Using a deprecated function on Darwin generates
-// a warning.
-#cgo CFLAGS: -Wno-error -Wno-deprecated-declarations
+#cgo CFLAGS: -mmacosx-version-min=10.6 -D__MAC_OS_X_VERSION_MAX_ALLOWED=1060
 #cgo LDFLAGS: -framework CoreFoundation -framework Security
+
 #include <CoreFoundation/CoreFoundation.h>
 #include <Security/Security.h>
 
@@ -40,26 +38,12 @@ int FetchPEMRoots(CFDataRef *pemRoots) {
 			continue;
 		}
 
-		// SecKeychainImportExport is deprecated in >= OS X 10.7, and has been replaced by
-		// SecItemExport.  If we're built on a host with a Lion SDK, this code gets conditionally
-		// included in the output, also for binaries meant for 10.6.
-		//
-		// To make sure that we run on both Mac OS X 10.6 and 10.7 we use weak linking
-		// and check whether SecItemExport is available before we attempt to call it. On
-		// 10.6, this won't be the case, and we'll fall back to calling SecKeychainItemExport.
-#if __MAC_OS_X_VERSION_MAX_ALLOWED >= 1070
-		if (SecItemExport) {
-			err = SecItemExport(cert, kSecFormatX509Cert, kSecItemPemArmour, NULL, &data);
-			if (err != noErr) {
-				continue;
-			}
-		} else
-#endif
-		if (data == NULL) {
-			err = SecKeychainItemExport(cert, kSecFormatX509Cert, kSecItemPemArmour, NULL, &data);
-			if (err != noErr) {
-				continue;
-			}
+		// Note: SecKeychainItemExport is deprecated as of 10.7 in favor of SecItemExport.
+		// Once we support weak imports via cgo we should prefer that, and fall back to this
+		// for older systems.
+		err = SecKeychainItemExport(cert, kSecFormatX509Cert, kSecItemPemArmour, NULL, &data);
+		if (err != noErr) {
+			continue;
 		}
 
 		if (data != NULL) {
diff --git a/libgo/go/crypto/x509/verify.go b/libgo/go/crypto/x509/verify.go
index 87b1cb7bb1c..3859dd8d488 100644
--- a/libgo/go/crypto/x509/verify.go
+++ b/libgo/go/crypto/x509/verify.go
@@ -135,8 +135,8 @@ func (c *Certificate) isValid(certType int, opts *VerifyOptions) error {
 
 // Verify attempts to verify c by building one or more chains from c to a
 // certificate in opts.roots, using certificates in opts.Intermediates if
-// needed. If successful, it returns one or chains where the first element of
-// the chain is c and the last element is from opts.Roots.
+// needed. If successful, it returns one or more chains where the first
+// element of the chain is c and the last element is from opts.Roots.
 //
 // WARNING: this doesn't do any revocation checking.
 func (c *Certificate) Verify(opts VerifyOptions) (chains [][]*Certificate, err error) {
diff --git a/libgo/go/crypto/x509/x509.go b/libgo/go/crypto/x509/x509.go
index 3116525d33d..f5da86b54a0 100644
--- a/libgo/go/crypto/x509/x509.go
+++ b/libgo/go/crypto/x509/x509.go
@@ -153,7 +153,7 @@ const (
 //
 // md2WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 2 }
 //
-// md5WithRSAEncryption OBJECT IDENTIFER ::= { pkcs-1 4 }
+// md5WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 4 }
 //
 // sha-1WithRSAEncryption OBJECT IDENTIFIER ::= { pkcs-1 5 }
 // 
@@ -172,9 +172,9 @@ const (
 //
 // RFC 5758 3.1 DSA Signature Algorithms
 //
-// dsaWithSha356 OBJECT IDENTIFER ::= {
+// dsaWithSha256 OBJECT IDENTIFIER ::= {
 //    joint-iso-ccitt(2) country(16) us(840) organization(1) gov(101)
-//    algorithms(4) id-dsa-with-sha2(3) 2}
+//    csor(3) algorithms(4) id-dsa-with-sha2(3) 2}
 //
 var (
 	oidSignatureMD2WithRSA    = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 1, 2}
diff --git a/libgo/go/encoding/binary/binary.go b/libgo/go/encoding/binary/binary.go
index b26b1bb2c93..02f090d53f3 100644
--- a/libgo/go/encoding/binary/binary.go
+++ b/libgo/go/encoding/binary/binary.go
@@ -29,17 +29,13 @@ type ByteOrder interface {
 	String() string
 }
 
-// This is byte instead of struct{} so that it can be compared,
-// allowing, e.g., order == binary.LittleEndian.
-type unused byte
-
 // LittleEndian is the little-endian implementation of ByteOrder.
 var LittleEndian littleEndian
 
 // BigEndian is the big-endian implementation of ByteOrder.
 var BigEndian bigEndian
 
-type littleEndian unused
+type littleEndian struct{}
 
 func (littleEndian) Uint16(b []byte) uint16 { return uint16(b[0]) | uint16(b[1])<<8 }
 
@@ -79,7 +75,7 @@ func (littleEndian) String() string { return "LittleEndian" }
 
 func (littleEndian) GoString() string { return "binary.LittleEndian" }
 
-type bigEndian unused
+type bigEndian struct{}
 
 func (bigEndian) Uint16(b []byte) uint16 { return uint16(b[1]) | uint16(b[0])<<8 }
 
diff --git a/libgo/go/encoding/gob/codec_test.go b/libgo/go/encoding/gob/codec_test.go
index d365f826345..ebcbb78ebe6 100644
--- a/libgo/go/encoding/gob/codec_test.go
+++ b/libgo/go/encoding/gob/codec_test.go
@@ -1455,11 +1455,14 @@ func TestFuzz(t *testing.T) {
 func TestFuzzRegressions(t *testing.T) {
 	// An instance triggering a type name of length ~102 GB.
 	testFuzz(t, 1328492090837718000, 100, new(float32))
+	// An instance triggering a type name of 1.6 GB.
+	// Commented out because it takes 5m to run.
+	//testFuzz(t, 1330522872628565000, 100, new(int))
 }
 
 func testFuzz(t *testing.T, seed int64, n int, input ...interface{}) {
-	t.Logf("seed=%d n=%d\n", seed, n)
 	for _, e := range input {
+		t.Logf("seed=%d n=%d e=%T", seed, n, e)
 		rng := rand.New(rand.NewSource(seed))
 		for i := 0; i < n; i++ {
 			encFuzzDec(rng, e)
diff --git a/libgo/go/encoding/gob/debug.go b/libgo/go/encoding/gob/debug.go
index b54ef46f52c..31d1351fc4f 100644
--- a/libgo/go/encoding/gob/debug.go
+++ b/libgo/go/encoding/gob/debug.go
@@ -3,14 +3,15 @@
 // license that can be found in the LICENSE file.
 
 // Delete the next line to include in the gob package.
-// +build gob-debug
+// +build ignore
 
 package gob
 
 // This file is not normally included in the gob package.  Used only for debugging the package itself.
-// Add debug.go to the files listed in the Makefile to add Debug to the gob package.
 // Except for reading uints, it is an implementation of a reader that is independent of
 // the one implemented by Decoder.
+// To enable the Debug function, delete the +build ignore line above and do
+//	go install
 
 import (
 	"bytes"
diff --git a/libgo/go/encoding/gob/decode.go b/libgo/go/encoding/gob/decode.go
index a0bb985300f..0708a83c99a 100644
--- a/libgo/go/encoding/gob/decode.go
+++ b/libgo/go/encoding/gob/decode.go
@@ -392,12 +392,12 @@ func decUint8Slice(i *decInstr, state *decoderState, p unsafe.Pointer) {
 		}
 		p = *(*unsafe.Pointer)(p)
 	}
-	n := int(state.decodeUint())
-	if n < 0 {
-		errorf("negative length decoding []byte")
+	n := state.decodeUint()
+	if n > uint64(state.b.Len()) {
+		errorf("length of []byte exceeds input size (%d bytes)", n)
 	}
 	slice := (*[]uint8)(p)
-	if cap(*slice) < n {
+	if uint64(cap(*slice)) < n {
 		*slice = make([]uint8, n)
 	} else {
 		*slice = (*slice)[0:n]
@@ -417,7 +417,11 @@ func decString(i *decInstr, state *decoderState, p unsafe.Pointer) {
 		}
 		p = *(*unsafe.Pointer)(p)
 	}
-	b := make([]byte, state.decodeUint())
+	n := state.decodeUint()
+	if n > uint64(state.b.Len()) {
+		errorf("string length exceeds input size (%d bytes)", n)
+	}
+	b := make([]byte, n)
 	state.b.Read(b)
 	// It would be a shame to do the obvious thing here,
 	//	*(*string)(p) = string(b)
@@ -647,7 +651,11 @@ func (dec *Decoder) ignoreMap(state *decoderState, keyOp, elemOp decOp) {
 // decodeSlice decodes a slice and stores the slice header through p.
 // Slices are encoded as an unsigned length followed by the elements.
 func (dec *Decoder) decodeSlice(atyp reflect.Type, state *decoderState, p uintptr, elemOp decOp, elemWid uintptr, indir, elemIndir int, ovfl error) {
-	n := int(uintptr(state.decodeUint()))
+	nr := state.decodeUint()
+	if nr > uint64(state.b.Len()) {
+		errorf("length of slice exceeds input size (%d elements)", nr)
+	}
+	n := int(nr)
 	if indir > 0 {
 		up := unsafe.Pointer(p)
 		if *(*unsafe.Pointer)(up) == nil {
@@ -702,6 +710,9 @@ func (dec *Decoder) decodeInterface(ityp reflect.Type, state *decoderState, p ui
 		*(*[2]uintptr)(unsafe.Pointer(p)) = ivalue.InterfaceData()
 		return
 	}
+	if len(name) > 1024 {
+		errorf("name too long (%d bytes): %.20q...", len(name), name)
+	}
 	// The concrete type must be registered.
 	typ, ok := nameToConcreteType[name]
 	if !ok {
diff --git a/libgo/go/encoding/gob/dump.go b/libgo/go/encoding/gob/dump.go
index e23a11e48bf..17238c98df0 100644
--- a/libgo/go/encoding/gob/dump.go
+++ b/libgo/go/encoding/gob/dump.go
@@ -7,6 +7,7 @@
 package main
 
 // Need to compile package gob with debug.go to build this program.
+// See comments in debug.go for how to do this.
 
 import (
 	"encoding/gob"
diff --git a/libgo/go/encoding/gob/encoder_test.go b/libgo/go/encoding/gob/encoder_test.go
index 3bfae30f39a..050786dfd1f 100644
--- a/libgo/go/encoding/gob/encoder_test.go
+++ b/libgo/go/encoding/gob/encoder_test.go
@@ -709,7 +709,7 @@ func TestGobPtrSlices(t *testing.T) {
 		t.Fatal("decode:", err)
 	}
 	if !reflect.DeepEqual(in, out) {
-		t.Fatal("got %v; wanted %v", out, in)
+		t.Fatalf("got %v; wanted %v", out, in)
 	}
 }
 
diff --git a/libgo/go/encoding/json/decode_test.go b/libgo/go/encoding/json/decode_test.go
index 0eec586a9bb..d758758d978 100644
--- a/libgo/go/encoding/json/decode_test.go
+++ b/libgo/go/encoding/json/decode_test.go
@@ -239,16 +239,6 @@ func TestEscape(t *testing.T) {
 	}
 }
 
-func TestHTMLEscape(t *testing.T) {
-	b, err := MarshalForHTML("foobarbaz<>&quux")
-	if err != nil {
-		t.Fatalf("MarshalForHTML error: %v", err)
-	}
-	if !bytes.Equal(b, []byte(`"foobarbaz\u003c\u003e\u0026quux"`)) {
-		t.Fatalf("Unexpected encoding of \"<>&\": %s", b)
-	}
-}
-
 // WrongString is a struct that's misusing the ,string modifier.
 type WrongString struct {
 	Message string `json:"result,string"`
diff --git a/libgo/go/encoding/json/encode.go b/libgo/go/encoding/json/encode.go
index 8a794b79bd5..5425a3a90a1 100644
--- a/libgo/go/encoding/json/encode.go
+++ b/libgo/go/encoding/json/encode.go
@@ -123,17 +123,6 @@ func MarshalIndent(v interface{}, prefix, indent string) ([]byte, error) {
 	return buf.Bytes(), nil
 }
 
-// MarshalForHTML is like Marshal but applies HTMLEscape to the output.
-func MarshalForHTML(v interface{}) ([]byte, error) {
-	b, err := Marshal(v)
-	if err != nil {
-		return nil, err
-	}
-	var buf bytes.Buffer
-	HTMLEscape(&buf, b)
-	return buf.Bytes(), nil
-}
-
 // HTMLEscape appends to dst the JSON-encoded src with <, >, and &
 // characters inside string literals changed to \u003c, \u003e, \u0026
 // so that the JSON will be safe to embed inside HTML <script> tags.
@@ -200,11 +189,6 @@ func (e *MarshalerError) Error() string {
 	return "json: error calling MarshalJSON for type " + e.Type.String() + ": " + e.Err.Error()
 }
 
-type interfaceOrPtrValue interface {
-	IsNil() bool
-	Elem() reflect.Value
-}
-
 var hex = "0123456789abcdef"
 
 // An encodeState encodes JSON into a bytes.Buffer.
@@ -276,7 +260,7 @@ func (e *encodeState) reflectValueQuoted(v reflect.Value, quoted bool) {
 		b, err := m.MarshalJSON()
 		if err == nil {
 			// copy JSON into buffer, checking validity.
-			err = Compact(&e.Buffer, b)
+			err = compact(&e.Buffer, b, true)
 		}
 		if err != nil {
 			e.error(&MarshalerError{v.Type(), err})
diff --git a/libgo/go/encoding/json/encode_test.go b/libgo/go/encoding/json/encode_test.go
index 7a726a91c47..cb1c77eb529 100644
--- a/libgo/go/encoding/json/encode_test.go
+++ b/libgo/go/encoding/json/encode_test.go
@@ -167,3 +167,22 @@ func TestRefValMarshal(t *testing.T) {
 		t.Errorf("got %q, want %q", got, want)
 	}
 }
+
+// C implements Marshaler and returns unescaped JSON.
+type C int
+
+func (C) MarshalJSON() ([]byte, error) {
+	return []byte(`"<&>"`), nil
+}
+
+func TestMarshalerEscaping(t *testing.T) {
+	var c C
+	const want = `"\u003c\u0026\u003e"`
+	b, err := Marshal(c)
+	if err != nil {
+		t.Fatalf("Marshal: %v", err)
+	}
+	if got := string(b); got != want {
+		t.Errorf("got %q, want %q", got, want)
+	}
+}
diff --git a/libgo/go/encoding/json/indent.go b/libgo/go/encoding/json/indent.go
index 5ba19b07ac6..e8dfa4ec436 100644
--- a/libgo/go/encoding/json/indent.go
+++ b/libgo/go/encoding/json/indent.go
@@ -9,11 +9,24 @@ import "bytes"
 // Compact appends to dst the JSON-encoded src with
 // insignificant space characters elided.
 func Compact(dst *bytes.Buffer, src []byte) error {
+	return compact(dst, src, false)
+}
+
+func compact(dst *bytes.Buffer, src []byte, escape bool) error {
 	origLen := dst.Len()
 	var scan scanner
 	scan.reset()
 	start := 0
 	for i, c := range src {
+		if escape && (c == '<' || c == '>' || c == '&') {
+			if start < i {
+				dst.Write(src[start:i])
+			}
+			dst.WriteString(`\u00`)
+			dst.WriteByte(hex[c>>4])
+			dst.WriteByte(hex[c&0xF])
+			start = i + 1
+		}
 		v := scan.step(&scan, int(c))
 		if v >= scanSkipSpace {
 			if v == scanError {
diff --git a/libgo/go/encoding/xml/marshal_test.go b/libgo/go/encoding/xml/marshal_test.go
index 9170fccd243..b6978a1e65b 100644
--- a/libgo/go/encoding/xml/marshal_test.go
+++ b/libgo/go/encoding/xml/marshal_test.go
@@ -136,12 +136,12 @@ type NamePrecedence struct {
 
 type XMLNameWithTag struct {
 	XMLName Name   `xml:"InXMLNameTag"`
-	Value   string ",chardata"
+	Value   string `xml:",chardata"`
 }
 
 type XMLNameWithoutTag struct {
 	XMLName Name
-	Value   string ",chardata"
+	Value   string `xml:",chardata"`
 }
 
 type NameInField struct {
@@ -532,9 +532,9 @@ var marshalTests = []struct {
 			InFieldName: "D",
 		},
 		ExpectXML: `<Parent>` +
-			`<InTag><Value>A</Value></InTag>` +
-			`<InXMLName><Value>B</Value></InXMLName>` +
-			`<InXMLNameTag><Value>C</Value></InXMLNameTag>` +
+			`<InTag>A</InTag>` +
+			`<InXMLName>B</InXMLName>` +
+			`<InXMLNameTag>C</InXMLNameTag>` +
 			`<InFieldName>D</InFieldName>` +
 			`</Parent>`,
 		MarshalOnly: true,
@@ -548,9 +548,9 @@ var marshalTests = []struct {
 			InFieldName: "D",
 		},
 		ExpectXML: `<Parent>` +
-			`<InTag><Value>A</Value></InTag>` +
-			`<FromNameVal><Value>B</Value></FromNameVal>` +
-			`<InXMLNameTag><Value>C</Value></InXMLNameTag>` +
+			`<InTag>A</InTag>` +
+			`<FromNameVal>B</FromNameVal>` +
+			`<InXMLNameTag>C</InXMLNameTag>` +
 			`<InFieldName>D</InFieldName>` +
 			`</Parent>`,
 		UnmarshalOnly: true,
diff --git a/libgo/go/exp/gotype/doc.go b/libgo/go/exp/gotype/doc.go
index 1aa0faa751a..1168086771f 100644
--- a/libgo/go/exp/gotype/doc.go
+++ b/libgo/go/exp/gotype/doc.go
@@ -34,6 +34,8 @@ The flags are:
 		Verbose mode.
 
 Debugging flags:
+	-comments
+		Parse comments (ignored if -ast not set).
 	-ast
 		Print AST (disables concurrent parsing).
 	-trace
diff --git a/libgo/go/exp/gotype/gotype.go b/libgo/go/exp/gotype/gotype.go
index a2a9361866d..30eaf22fca6 100644
--- a/libgo/go/exp/gotype/gotype.go
+++ b/libgo/go/exp/gotype/gotype.go
@@ -27,8 +27,9 @@ var (
 	allErrors = flag.Bool("e", false, "print all (including spurious) errors")
 
 	// debugging support
-	printTrace = flag.Bool("trace", false, "print parse trace")
-	printAST   = flag.Bool("ast", false, "print AST")
+	parseComments = flag.Bool("comments", false, "parse comments (ignored if -ast not set)")
+	printTrace    = flag.Bool("trace", false, "print parse trace")
+	printAST      = flag.Bool("ast", false, "print AST")
 )
 
 var exitCode = 0
@@ -73,6 +74,9 @@ func parse(fset *token.FileSet, filename string, src []byte) *ast.File {
 	if *allErrors {
 		mode |= parser.SpuriousErrors
 	}
+	if *parseComments && *printAST {
+		mode |= parser.ParseComments
+	}
 	if *printTrace {
 		mode |= parser.Trace
 	}
diff --git a/libgo/go/exp/html/node.go b/libgo/go/exp/html/node.go
index 83f17308b18..c105a4e709a 100644
--- a/libgo/go/exp/html/node.go
+++ b/libgo/go/exp/html/node.go
@@ -110,7 +110,7 @@ func (s *nodeStack) top() *Node {
 	return nil
 }
 
-// index returns the index of the top-most occurence of n in the stack, or -1
+// index returns the index of the top-most occurrence of n in the stack, or -1
 // if n is not present.
 func (s *nodeStack) index(n *Node) int {
 	for i := len(*s) - 1; i >= 0; i-- {
diff --git a/libgo/go/exp/norm/forminfo.go b/libgo/go/exp/norm/forminfo.go
index fd7b3956233..c443b78d825 100644
--- a/libgo/go/exp/norm/forminfo.go
+++ b/libgo/go/exp/norm/forminfo.go
@@ -18,17 +18,17 @@ package norm
 // has the form:
 //    <header> <decomp_byte>* [<tccc> [<lccc>]]
 // The header contains the number of bytes in the decomposition (excluding this
-// length byte). The two most significant bits of this lenght byte correspond
+// length byte). The two most significant bits of this length byte correspond
 // to bit 2 and 3 of qcIfo (see below).  The byte sequence itself starts at v+1.
 // The byte sequence is followed by a trailing and leading CCC if the values
 // for these are not zero.  The value of v determines which ccc are appended
 // to the sequences.  For v < firstCCC, there are none, for v >= firstCCC,
-// the seqence is followed by a trailing ccc, and for v >= firstLeadingCC
+// the sequence is followed by a trailing ccc, and for v >= firstLeadingCC
 // there is an additional leading ccc.
 
 const (
 	qcInfoMask      = 0xF  // to clear all but the relevant bits in a qcInfo
-	headerLenMask   = 0x3F // extract the lenght value from the header byte
+	headerLenMask   = 0x3F // extract the length value from the header byte
 	headerFlagsMask = 0xC0 // extract the qcInfo bits from the header byte
 )
 
diff --git a/libgo/go/exp/proxy/per_host.go b/libgo/go/exp/proxy/per_host.go
index 397ef57cd92..0c627e9ab54 100644
--- a/libgo/go/exp/proxy/per_host.go
+++ b/libgo/go/exp/proxy/per_host.go
@@ -75,7 +75,7 @@ func (p *PerHost) dialerForRequest(host string) Dialer {
 }
 
 // AddFromString parses a string that contains comma-separated values
-// specifing hosts that should use the bypass proxy. Each value is either an
+// specifying hosts that should use the bypass proxy. Each value is either an
 // IP address, a CIDR range, a zone (*.example.com) or a hostname
 // (localhost). A best effort is made to parse the string and errors are
 // ignored.
diff --git a/libgo/go/exp/types/gcimporter.go b/libgo/go/exp/types/gcimporter.go
index 8b28aede1ec..cb996f28055 100644
--- a/libgo/go/exp/types/gcimporter.go
+++ b/libgo/go/exp/types/gcimporter.go
@@ -18,6 +18,7 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
+	"strings"
 	"text/scanner"
 )
 
@@ -39,11 +40,14 @@ func findPkg(path string) (filename, id string) {
 	switch path[0] {
 	default:
 		// "x" -> "$GOPATH/pkg/$GOOS_$GOARCH/x.ext", "x"
-		tree, pkg, err := build.FindTree(path)
-		if err != nil {
+		bp, _ := build.Import(path, "", build.FindOnly)
+		if bp.PkgObj == "" {
 			return
 		}
-		noext = filepath.Join(tree.PkgDir(), pkg)
+		noext = bp.PkgObj
+		if strings.HasSuffix(noext, ".a") {
+			noext = noext[:len(noext)-2]
+		}
 
 	case '.':
 		// "./x" -> "/this/directory/x.ext", "/this/directory/x"
@@ -742,7 +746,7 @@ func (p *gcParser) parseVarDecl() {
 }
 
 // FuncBody = "{" ... "}" .
-// 
+//
 func (p *gcParser) parseFuncBody() {
 	p.expect('{')
 	for i := 1; i > 0; p.next() {
diff --git a/libgo/go/exp/types/types.go b/libgo/go/exp/types/types.go
index 3aa896892e3..85d244cf04a 100644
--- a/libgo/go/exp/types/types.go
+++ b/libgo/go/exp/types/types.go
@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// PACKAGE UNDER CONSTRUCTION. ANY AND ALL PARTS MAY CHANGE.
-// Package types declares the types used to represent Go types.
+// Package types declares the types used to represent Go types
+// (UNDER CONSTRUCTION). ANY AND ALL PARTS MAY CHANGE.
 //
 package types
 
diff --git a/libgo/go/go/ast/print.go b/libgo/go/go/ast/print.go
index f6c63c0d889..02cf9e02234 100644
--- a/libgo/go/go/ast/print.go
+++ b/libgo/go/go/ast/print.go
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// This file contains printing suppport for ASTs.
+// This file contains printing support for ASTs.
 
 package ast
 
diff --git a/libgo/go/go/build/build.go b/libgo/go/go/build/build.go
index 68e8d342005..eece7610562 100644
--- a/libgo/go/go/build/build.go
+++ b/libgo/go/go/build/build.go
@@ -2,10 +2,948 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// Package build provides tools for building Go packages.
 package build
 
-import "errors"
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"go/ast"
+	"go/doc"
+	"go/parser"
+	"go/token"
+	"io"
+	"io/ioutil"
+	"log"
+	"os"
+	pathpkg "path"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strconv"
+	"strings"
+	"unicode"
+)
+
+// A Context specifies the supporting context for a build.
+type Context struct {
+	GOARCH      string   // target architecture
+	GOOS        string   // target operating system
+	GOROOT      string   // Go root
+	GOPATH      string   // Go path
+	CgoEnabled  bool     // whether cgo can be used
+	BuildTags   []string // additional tags to recognize in +build lines
+	UseAllFiles bool     // use files regardless of +build lines, file names
+	Gccgo       bool     // assume use of gccgo when computing object paths
+
+	// By default, Import uses the operating system's file system calls
+	// to read directories and files.  To read from other sources,
+	// callers can set the following functions.  They all have default
+	// behaviors that use the local file system, so clients need only set
+	// the functions whose behaviors they wish to change.
+
+	// JoinPath joins the sequence of path fragments into a single path.
+	// If JoinPath is nil, Import uses filepath.Join.
+	JoinPath func(elem ...string) string
+
+	// SplitPathList splits the path list into a slice of individual paths.
+	// If SplitPathList is nil, Import uses filepath.SplitList.
+	SplitPathList func(list string) []string
+
+	// IsAbsPath reports whether path is an absolute path.
+	// If IsAbsPath is nil, Import uses filepath.IsAbs.
+	IsAbsPath func(path string) bool
+
+	// IsDir reports whether the path names a directory.
+	// If IsDir is nil, Import calls os.Stat and uses the result's IsDir method.
+	IsDir func(path string) bool
+
+	// HasSubdir reports whether dir is a subdirectory of
+	// (perhaps multiple levels below) root.
+	// If so, HasSubdir sets rel to a slash-separated path that
+	// can be joined to root to produce a path equivalent to dir.
+	// If HasSubdir is nil, Import uses an implementation built on
+	// filepath.EvalSymlinks.
+	HasSubdir func(root, dir string) (rel string, ok bool)
+
+	// ReadDir returns a slice of os.FileInfo, sorted by Name,
+	// describing the content of the named directory.
+	// If ReadDir is nil, Import uses io.ReadDir.
+	ReadDir func(dir string) (fi []os.FileInfo, err error)
+
+	// OpenFile opens a file (not a directory) for reading.
+	// If OpenFile is nil, Import uses os.Open.
+	OpenFile func(path string) (r io.ReadCloser, err error)
+}
+
+// joinPath calls ctxt.JoinPath (if not nil) or else filepath.Join.
+func (ctxt *Context) joinPath(elem ...string) string {
+	if f := ctxt.JoinPath; f != nil {
+		return f(elem...)
+	}
+	return filepath.Join(elem...)
+}
+
+// splitPathList calls ctxt.SplitPathList (if not nil) or else filepath.SplitList.
+func (ctxt *Context) splitPathList(s string) []string {
+	if f := ctxt.SplitPathList; f != nil {
+		return f(s)
+	}
+	return filepath.SplitList(s)
+}
+
+// isAbsPath calls ctxt.IsAbsSPath (if not nil) or else filepath.IsAbs.
+func (ctxt *Context) isAbsPath(path string) bool {
+	if f := ctxt.IsAbsPath; f != nil {
+		return f(path)
+	}
+	return filepath.IsAbs(path)
+}
+
+// isDir calls ctxt.IsDir (if not nil) or else uses os.Stat.
+func (ctxt *Context) isDir(path string) bool {
+	if f := ctxt.IsDir; f != nil {
+		return f(path)
+	}
+	fi, err := os.Stat(path)
+	return err == nil && fi.IsDir()
+}
+
+// hasSubdir calls ctxt.HasSubdir (if not nil) or else uses
+// the local file system to answer the question.
+func (ctxt *Context) hasSubdir(root, dir string) (rel string, ok bool) {
+	if f := ctxt.HasSubdir; f != nil {
+		return f(root, dir)
+	}
+
+	if p, err := filepath.EvalSymlinks(root); err == nil {
+		root = p
+	}
+	if p, err := filepath.EvalSymlinks(dir); err == nil {
+		dir = p
+	}
+	const sep = string(filepath.Separator)
+	root = filepath.Clean(root)
+	if !strings.HasSuffix(root, sep) {
+		root += sep
+	}
+	dir = filepath.Clean(dir)
+	if !strings.HasPrefix(dir, root) {
+		return "", false
+	}
+	return filepath.ToSlash(dir[len(root):]), true
+}
+
+// readDir calls ctxt.ReadDir (if not nil) or else ioutil.ReadDir.
+func (ctxt *Context) readDir(path string) ([]os.FileInfo, error) {
+	if f := ctxt.ReadDir; f != nil {
+		return f(path)
+	}
+	return ioutil.ReadDir(path)
+}
+
+// openFile calls ctxt.OpenFile (if not nil) or else os.Open.
+func (ctxt *Context) openFile(path string) (io.ReadCloser, error) {
+	if fn := ctxt.OpenFile; fn != nil {
+		return fn(path)
+	}
+
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err // nil interface
+	}
+	return f, nil
+}
+
+// isFile determines whether path is a file by trying to open it.
+// It reuses openFile instead of adding another function to the
+// list in Context.
+func (ctxt *Context) isFile(path string) bool {
+	f, err := ctxt.openFile(path)
+	if err != nil {
+		return false
+	}
+	f.Close()
+	return true
+}
+
+// gopath returns the list of Go path directories.
+func (ctxt *Context) gopath() []string {
+	var all []string
+	for _, p := range ctxt.splitPathList(ctxt.GOPATH) {
+		if p == "" || p == ctxt.GOROOT {
+			// Empty paths are uninteresting.
+			// If the path is the GOROOT, ignore it.
+			// People sometimes set GOPATH=$GOROOT, which is useless
+			// but would cause us to find packages with import paths
+			// like "pkg/math".
+			// Do not get confused by this common mistake.
+			continue
+		}
+		all = append(all, p)
+	}
+	return all
+}
+
+// SrcDirs returns a list of package source root directories.
+// It draws from the current Go root and Go path but omits directories
+// that do not exist.
+func (ctxt *Context) SrcDirs() []string {
+	var all []string
+	if ctxt.GOROOT != "" {
+		dir := ctxt.joinPath(ctxt.GOROOT, "src", "pkg")
+		if ctxt.isDir(dir) {
+			all = append(all, dir)
+		}
+	}
+	for _, p := range ctxt.gopath() {
+		dir := ctxt.joinPath(p, "src")
+		if ctxt.isDir(dir) {
+			all = append(all, dir)
+		}
+	}
+	return all
+}
+
+// Default is the default Context for builds.
+// It uses the GOARCH, GOOS, GOROOT, and GOPATH environment variables
+// if set, or else the compiled code's GOARCH, GOOS, and GOROOT.
+var Default Context = defaultContext()
+
+var cgoEnabled = map[string]bool{
+	"darwin/386":    true,
+	"darwin/amd64":  true,
+	"linux/386":     true,
+	"linux/amd64":   true,
+	"freebsd/386":   true,
+	"freebsd/amd64": true,
+	"windows/386":   true,
+	"windows/amd64": true,
+}
+
+func defaultContext() Context {
+	var c Context
+
+	c.GOARCH = envOr("GOARCH", runtime.GOARCH)
+	c.GOOS = envOr("GOOS", runtime.GOOS)
+	c.GOROOT = runtime.GOROOT()
+	c.GOPATH = envOr("GOPATH", "")
+
+	switch os.Getenv("CGO_ENABLED") {
+	case "1":
+		c.CgoEnabled = true
+	case "0":
+		c.CgoEnabled = false
+	default:
+		c.CgoEnabled = cgoEnabled[c.GOOS+"/"+c.GOARCH]
+	}
+
+	return c
+}
+
+func envOr(name, def string) string {
+	s := os.Getenv(name)
+	if s == "" {
+		return def
+	}
+	return s
+}
+
+// An ImportMode controls the behavior of the Import method.
+type ImportMode uint
+
+const (
+	// If FindOnly is set, Import stops after locating the directory
+	// that should contain the sources for a package.  It does not
+	// read any files in the directory.
+	FindOnly ImportMode = 1 << iota
+
+	// If AllowBinary is set, Import can be satisfied by a compiled
+	// package object without corresponding sources.
+	AllowBinary
+)
+
+// A Package describes the Go package found in a directory.
+type Package struct {
+	Dir        string // directory containing package sources
+	Name       string // package name
+	Doc        string // documentation synopsis
+	ImportPath string // import path of package ("" if unknown)
+	Root       string // root of Go tree where this package lives
+	SrcRoot    string // package source root directory ("" if unknown)
+	PkgRoot    string // package install root directory ("" if unknown)
+	BinDir     string // command install directory ("" if unknown)
+	Goroot     bool   // package found in Go root
+	PkgObj     string // installed .a file
+
+	// Source files
+	GoFiles  []string // .go source files (excluding CgoFiles, TestGoFiles, XTestGoFiles)
+	CgoFiles []string // .go source files that import "C"
+	CFiles   []string // .c source files
+	HFiles   []string // .h source files
+	SFiles   []string // .s source files
+
+	// Cgo directives
+	CgoPkgConfig []string // Cgo pkg-config directives
+	CgoCFLAGS    []string // Cgo CFLAGS directives
+	CgoLDFLAGS   []string // Cgo LDFLAGS directives
+
+	// Dependency information
+	Imports   []string                    // imports from GoFiles, CgoFiles
+	ImportPos map[string][]token.Position // line information for Imports
+
+	// Test information
+	TestGoFiles    []string                    // _test.go files in package
+	TestImports    []string                    // imports from TestGoFiles
+	TestImportPos  map[string][]token.Position // line information for TestImports
+	XTestGoFiles   []string                    // _test.go files outside package
+	XTestImports   []string                    // imports from XTestGoFiles
+	XTestImportPos map[string][]token.Position // line information for XTestImports
+}
+
+// IsCommand reports whether the package is considered a
+// command to be installed (not just a library).
+// Packages named "main" are treated as commands.
+func (p *Package) IsCommand() bool {
+	return p.Name == "main"
+}
+
+// ImportDir is like Import but processes the Go package found in
+// the named directory.
+func (ctxt *Context) ImportDir(dir string, mode ImportMode) (*Package, error) {
+	return ctxt.Import(".", dir, mode)
+}
+
+// Import returns details about the Go package named by the import path,
+// interpreting local import paths relative to the src directory.  If the path
+// is a local import path naming a package that can be imported using a
+// standard import path, the returned package will set p.ImportPath to
+// that path.
+//
+// In the directory containing the package, .go, .c, .h, and .s files are
+// considered part of the package except for:
+//
+//	- .go files in package documentation
+//	- files starting with _ or .
+//	- files with build constraints not satisfied by the context
+//
+// If an error occurs, Import returns a non-nil error also returns a non-nil
+// *Package containing partial information.
+//
+func (ctxt *Context) Import(path string, src string, mode ImportMode) (*Package, error) {
+	p := &Package{
+		ImportPath: path,
+	}
+
+	var pkga string
+	if ctxt.Gccgo {
+		dir, elem := pathpkg.Split(p.ImportPath)
+		pkga = "pkg/gccgo/" + dir + "lib" + elem + ".a"
+	} else {
+		pkga = "pkg/" + ctxt.GOOS + "_" + ctxt.GOARCH + "/" + p.ImportPath + ".a"
+	}
+
+	binaryOnly := false
+	if IsLocalImport(path) {
+		if src == "" {
+			return p, fmt.Errorf("import %q: import relative to unknown directory", path)
+		}
+		if !ctxt.isAbsPath(path) {
+			p.Dir = ctxt.joinPath(src, path)
+		}
+		// Determine canonical import path, if any.
+		if ctxt.GOROOT != "" {
+			root := ctxt.joinPath(ctxt.GOROOT, "src", "pkg")
+			if sub, ok := ctxt.hasSubdir(root, p.Dir); ok {
+				p.Goroot = true
+				p.ImportPath = sub
+				p.Root = ctxt.GOROOT
+				goto Found
+			}
+		}
+		all := ctxt.gopath()
+		for i, root := range all {
+			rootsrc := ctxt.joinPath(root, "src")
+			if sub, ok := ctxt.hasSubdir(rootsrc, p.Dir); ok {
+				// We found a potential import path for dir,
+				// but check that using it wouldn't find something
+				// else first.
+				if ctxt.GOROOT != "" {
+					if dir := ctxt.joinPath(ctxt.GOROOT, "src", sub); ctxt.isDir(dir) {
+						goto Found
+					}
+				}
+				for _, earlyRoot := range all[:i] {
+					if dir := ctxt.joinPath(earlyRoot, "src", sub); ctxt.isDir(dir) {
+						goto Found
+					}
+				}
+
+				// sub would not name some other directory instead of this one.
+				// Record it.
+				p.ImportPath = sub
+				p.Root = root
+				goto Found
+			}
+		}
+		// It's okay that we didn't find a root containing dir.
+		// Keep going with the information we have.
+	} else {
+		if strings.HasPrefix(path, "/") {
+			return p, fmt.Errorf("import %q: cannot import absolute path", path)
+		}
+		// Determine directory from import path.
+		if ctxt.GOROOT != "" {
+			dir := ctxt.joinPath(ctxt.GOROOT, "src", "pkg", path)
+			isDir := ctxt.isDir(dir)
+			binaryOnly = !isDir && mode&AllowBinary != 0 && ctxt.isFile(ctxt.joinPath(ctxt.GOROOT, pkga))
+			if isDir || binaryOnly {
+				p.Dir = dir
+				p.Goroot = true
+				p.Root = ctxt.GOROOT
+				goto Found
+			}
+		}
+		for _, root := range ctxt.gopath() {
+			dir := ctxt.joinPath(root, "src", path)
+			isDir := ctxt.isDir(dir)
+			binaryOnly = !isDir && mode&AllowBinary != 0 && ctxt.isFile(ctxt.joinPath(root, pkga))
+			if isDir || binaryOnly {
+				p.Dir = dir
+				p.Root = root
+				goto Found
+			}
+		}
+		return p, fmt.Errorf("import %q: cannot find package", path)
+	}
+
+Found:
+	if p.Root != "" {
+		if p.Goroot {
+			p.SrcRoot = ctxt.joinPath(p.Root, "src", "pkg")
+		} else {
+			p.SrcRoot = ctxt.joinPath(p.Root, "src")
+		}
+		p.PkgRoot = ctxt.joinPath(p.Root, "pkg")
+		p.BinDir = ctxt.joinPath(p.Root, "bin")
+		p.PkgObj = ctxt.joinPath(p.Root, pkga)
+	}
+
+	if mode&FindOnly != 0 {
+		return p, nil
+	}
+	if binaryOnly && (mode&AllowBinary) != 0 {
+		return p, nil
+	}
+
+	dirs, err := ctxt.readDir(p.Dir)
+	if err != nil {
+		return p, err
+	}
+
+	var Sfiles []string // files with ".S" (capital S)
+	var firstFile string
+	imported := make(map[string][]token.Position)
+	testImported := make(map[string][]token.Position)
+	xTestImported := make(map[string][]token.Position)
+	fset := token.NewFileSet()
+	for _, d := range dirs {
+		if d.IsDir() {
+			continue
+		}
+		name := d.Name()
+		if strings.HasPrefix(name, "_") ||
+			strings.HasPrefix(name, ".") {
+			continue
+		}
+		if !ctxt.UseAllFiles && !ctxt.goodOSArchFile(name) {
+			continue
+		}
+
+		i := strings.LastIndex(name, ".")
+		if i < 0 {
+			i = len(name)
+		}
+		ext := name[i:]
+		switch ext {
+		case ".go", ".c", ".s", ".h", ".S":
+			// tentatively okay
+		default:
+			// skip
+			continue
+		}
+
+		filename := ctxt.joinPath(p.Dir, name)
+		f, err := ctxt.openFile(filename)
+		if err != nil {
+			return p, err
+		}
+		data, err := ioutil.ReadAll(f)
+		f.Close()
+		if err != nil {
+			return p, fmt.Errorf("read %s: %v", filename, err)
+		}
+
+		// Look for +build comments to accept or reject the file.
+		if !ctxt.UseAllFiles && !ctxt.shouldBuild(data) {
+			continue
+		}
+
+		// Going to save the file.  For non-Go files, can stop here.
+		switch ext {
+		case ".c":
+			p.CFiles = append(p.CFiles, name)
+			continue
+		case ".h":
+			p.HFiles = append(p.HFiles, name)
+			continue
+		case ".s":
+			p.SFiles = append(p.SFiles, name)
+			continue
+		case ".S":
+			Sfiles = append(Sfiles, name)
+			continue
+		}
+
+		pf, err := parser.ParseFile(fset, filename, data, parser.ImportsOnly|parser.ParseComments)
+		if err != nil {
+			return p, err
+		}
+
+		pkg := string(pf.Name.Name)
+		if pkg == "documentation" {
+			continue
+		}
+
+		isTest := strings.HasSuffix(name, "_test.go")
+		isXTest := false
+		if isTest && strings.HasSuffix(pkg, "_test") {
+			isXTest = true
+			pkg = pkg[:len(pkg)-len("_test")]
+		}
+
+		if p.Name == "" {
+			p.Name = pkg
+			firstFile = name
+		} else if pkg != p.Name {
+			return p, fmt.Errorf("found packages %s (%s) and %s (%s) in %s", p.Name, firstFile, pkg, name, p.Dir)
+		}
+		if pf.Doc != nil && p.Doc == "" {
+			p.Doc = doc.Synopsis(pf.Doc.Text())
+		}
+
+		// Record imports and information about cgo.
+		isCgo := false
+		for _, decl := range pf.Decls {
+			d, ok := decl.(*ast.GenDecl)
+			if !ok {
+				continue
+			}
+			for _, dspec := range d.Specs {
+				spec, ok := dspec.(*ast.ImportSpec)
+				if !ok {
+					continue
+				}
+				quoted := string(spec.Path.Value)
+				path, err := strconv.Unquote(quoted)
+				if err != nil {
+					log.Panicf("%s: parser returned invalid quoted string: <%s>", filename, quoted)
+				}
+				if isXTest {
+					xTestImported[path] = append(xTestImported[path], fset.Position(spec.Pos()))
+				} else if isTest {
+					testImported[path] = append(testImported[path], fset.Position(spec.Pos()))
+				} else {
+					imported[path] = append(imported[path], fset.Position(spec.Pos()))
+				}
+				if path == "C" {
+					if isTest {
+						return p, fmt.Errorf("use of cgo in test %s not supported", filename)
+					}
+					cg := spec.Doc
+					if cg == nil && len(d.Specs) == 1 {
+						cg = d.Doc
+					}
+					if cg != nil {
+						if err := ctxt.saveCgo(filename, p, cg); err != nil {
+							return p, err
+						}
+					}
+					isCgo = true
+				}
+			}
+		}
+		if isCgo {
+			if ctxt.CgoEnabled {
+				p.CgoFiles = append(p.CgoFiles, name)
+			}
+		} else if isXTest {
+			p.XTestGoFiles = append(p.XTestGoFiles, name)
+		} else if isTest {
+			p.TestGoFiles = append(p.TestGoFiles, name)
+		} else {
+			p.GoFiles = append(p.GoFiles, name)
+		}
+	}
+	if p.Name == "" {
+		return p, fmt.Errorf("no Go source files in %s", p.Dir)
+	}
+
+	p.Imports, p.ImportPos = cleanImports(imported)
+	p.TestImports, p.TestImportPos = cleanImports(testImported)
+	p.XTestImports, p.XTestImportPos = cleanImports(xTestImported)
+
+	// add the .S files only if we are using cgo
+	// (which means gcc will compile them).
+	// The standard assemblers expect .s files.
+	if len(p.CgoFiles) > 0 {
+		p.SFiles = append(p.SFiles, Sfiles...)
+		sort.Strings(p.SFiles)
+	}
+
+	return p, nil
+}
+
+func cleanImports(m map[string][]token.Position) ([]string, map[string][]token.Position) {
+	all := make([]string, 0, len(m))
+	for path := range m {
+		all = append(all, path)
+	}
+	sort.Strings(all)
+	return all, m
+}
+
+// Import is shorthand for Default.Import.
+func Import(path, src string, mode ImportMode) (*Package, error) {
+	return Default.Import(path, src, mode)
+}
+
+// ImportDir is shorthand for Default.ImportDir.
+func ImportDir(dir string, mode ImportMode) (*Package, error) {
+	return Default.ImportDir(dir, mode)
+}
+
+var slashslash = []byte("//")
+
+// shouldBuild reports whether it is okay to use this file,
+// The rule is that in the file's leading run of // comments
+// and blank lines, which must be followed by a blank line
+// (to avoid including a Go package clause doc comment),
+// lines beginning with '// +build' are taken as build directives.
+//
+// The file is accepted only if each such line lists something
+// matching the file.  For example:
+//
+//	// +build windows linux
+//
+// marks the file as applicable only on Windows and Linux.
+//
+func (ctxt *Context) shouldBuild(content []byte) bool {
+	// Pass 1. Identify leading run of // comments and blank lines,
+	// which must be followed by a blank line.
+	end := 0
+	p := content
+	for len(p) > 0 {
+		line := p
+		if i := bytes.IndexByte(line, '\n'); i >= 0 {
+			line, p = line[:i], p[i+1:]
+		} else {
+			p = p[len(p):]
+		}
+		line = bytes.TrimSpace(line)
+		if len(line) == 0 { // Blank line
+			end = cap(content) - cap(line) // &line[0] - &content[0]
+			continue
+		}
+		if !bytes.HasPrefix(line, slashslash) { // Not comment line
+			break
+		}
+	}
+	content = content[:end]
+
+	// Pass 2.  Process each line in the run.
+	p = content
+	for len(p) > 0 {
+		line := p
+		if i := bytes.IndexByte(line, '\n'); i >= 0 {
+			line, p = line[:i], p[i+1:]
+		} else {
+			p = p[len(p):]
+		}
+		line = bytes.TrimSpace(line)
+		if bytes.HasPrefix(line, slashslash) {
+			line = bytes.TrimSpace(line[len(slashslash):])
+			if len(line) > 0 && line[0] == '+' {
+				// Looks like a comment +line.
+				f := strings.Fields(string(line))
+				if f[0] == "+build" {
+					ok := false
+					for _, tok := range f[1:] {
+						if ctxt.match(tok) {
+							ok = true
+							break
+						}
+					}
+					if !ok {
+						return false // this one doesn't match
+					}
+				}
+			}
+		}
+	}
+	return true // everything matches
+}
+
+// saveCgo saves the information from the #cgo lines in the import "C" comment.
+// These lines set CFLAGS and LDFLAGS and pkg-config directives that affect
+// the way cgo's C code is built.
+//
+// TODO(rsc): This duplicates code in cgo.
+// Once the dust settles, remove this code from cgo.
+func (ctxt *Context) saveCgo(filename string, di *Package, cg *ast.CommentGroup) error {
+	text := cg.Text()
+	for _, line := range strings.Split(text, "\n") {
+		orig := line
+
+		// Line is
+		//	#cgo [GOOS/GOARCH...] LDFLAGS: stuff
+		//
+		line = strings.TrimSpace(line)
+		if len(line) < 5 || line[:4] != "#cgo" || (line[4] != ' ' && line[4] != '\t') {
+			continue
+		}
+
+		// Split at colon.
+		line = strings.TrimSpace(line[4:])
+		i := strings.Index(line, ":")
+		if i < 0 {
+			return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
+		}
+		line, argstr := line[:i], line[i+1:]
+
+		// Parse GOOS/GOARCH stuff.
+		f := strings.Fields(line)
+		if len(f) < 1 {
+			return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
+		}
+
+		cond, verb := f[:len(f)-1], f[len(f)-1]
+		if len(cond) > 0 {
+			ok := false
+			for _, c := range cond {
+				if ctxt.match(c) {
+					ok = true
+					break
+				}
+			}
+			if !ok {
+				continue
+			}
+		}
+
+		args, err := splitQuoted(argstr)
+		if err != nil {
+			return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
+		}
+		for _, arg := range args {
+			if !safeName(arg) {
+				return fmt.Errorf("%s: malformed #cgo argument: %s", filename, arg)
+			}
+		}
+
+		switch verb {
+		case "CFLAGS":
+			di.CgoCFLAGS = append(di.CgoCFLAGS, args...)
+		case "LDFLAGS":
+			di.CgoLDFLAGS = append(di.CgoLDFLAGS, args...)
+		case "pkg-config":
+			di.CgoPkgConfig = append(di.CgoPkgConfig, args...)
+		default:
+			return fmt.Errorf("%s: invalid #cgo verb: %s", filename, orig)
+		}
+	}
+	return nil
+}
+
+var safeBytes = []byte("+-.,/0123456789=ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz:")
+
+func safeName(s string) bool {
+	if s == "" {
+		return false
+	}
+	for i := 0; i < len(s); i++ {
+		if c := s[i]; c < 0x80 && bytes.IndexByte(safeBytes, c) < 0 {
+			return false
+		}
+	}
+	return true
+}
+
+// splitQuoted splits the string s around each instance of one or more consecutive
+// white space characters while taking into account quotes and escaping, and
+// returns an array of substrings of s or an empty list if s contains only white space.
+// Single quotes and double quotes are recognized to prevent splitting within the
+// quoted region, and are removed from the resulting substrings. If a quote in s
+// isn't closed err will be set and r will have the unclosed argument as the
+// last element.  The backslash is used for escaping.
+//
+// For example, the following string:
+//
+//     a b:"c d" 'e''f'  "g\""
+//
+// Would be parsed as:
+//
+//     []string{"a", "b:c d", "ef", `g"`}
+//
+func splitQuoted(s string) (r []string, err error) {
+	var args []string
+	arg := make([]rune, len(s))
+	escaped := false
+	quoted := false
+	quote := '\x00'
+	i := 0
+	for _, rune := range s {
+		switch {
+		case escaped:
+			escaped = false
+		case rune == '\\':
+			escaped = true
+			continue
+		case quote != '\x00':
+			if rune == quote {
+				quote = '\x00'
+				continue
+			}
+		case rune == '"' || rune == '\'':
+			quoted = true
+			quote = rune
+			continue
+		case unicode.IsSpace(rune):
+			if quoted || i > 0 {
+				quoted = false
+				args = append(args, string(arg[:i]))
+				i = 0
+			}
+			continue
+		}
+		arg[i] = rune
+		i++
+	}
+	if quoted || i > 0 {
+		args = append(args, string(arg[:i]))
+	}
+	if quote != 0 {
+		err = errors.New("unclosed quote")
+	} else if escaped {
+		err = errors.New("unfinished escaping")
+	}
+	return args, err
+}
+
+// match returns true if the name is one of:
+//
+//	$GOOS
+//	$GOARCH
+//	cgo (if cgo is enabled)
+//	!cgo (if cgo is disabled)
+//	tag (if tag is listed in ctxt.BuildTags)
+//	!tag (if tag is not listed in ctxt.BuildTags)
+//	a slash-separated list of any of these
+//
+func (ctxt *Context) match(name string) bool {
+	if name == "" {
+		return false
+	}
+	if i := strings.Index(name, ","); i >= 0 {
+		// comma-separated list
+		return ctxt.match(name[:i]) && ctxt.match(name[i+1:])
+	}
+	if strings.HasPrefix(name, "!!") { // bad syntax, reject always
+		return false
+	}
+	if strings.HasPrefix(name, "!") { // negation
+		return !ctxt.match(name[1:])
+	}
+
+	// Tags must be letters, digits, underscores.
+	// Unlike in Go identifiers, all digits is fine (e.g., "386").
+	for _, c := range name {
+		if !unicode.IsLetter(c) && !unicode.IsDigit(c) && c != '_' {
+			return false
+		}
+	}
+
+	// special tags
+	if ctxt.CgoEnabled && name == "cgo" {
+		return true
+	}
+	if name == ctxt.GOOS || name == ctxt.GOARCH {
+		return true
+	}
+
+	// other tags
+	for _, tag := range ctxt.BuildTags {
+		if tag == name {
+			return true
+		}
+	}
+
+	return false
+}
+
+// goodOSArchFile returns false if the name contains a $GOOS or $GOARCH
+// suffix which does not match the current system.
+// The recognized name formats are:
+//
+//     name_$(GOOS).*
+//     name_$(GOARCH).*
+//     name_$(GOOS)_$(GOARCH).*
+//     name_$(GOOS)_test.*
+//     name_$(GOARCH)_test.*
+//     name_$(GOOS)_$(GOARCH)_test.*
+//
+func (ctxt *Context) goodOSArchFile(name string) bool {
+	if dot := strings.Index(name, "."); dot != -1 {
+		name = name[:dot]
+	}
+	l := strings.Split(name, "_")
+	if n := len(l); n > 0 && l[n-1] == "test" {
+		l = l[:n-1]
+	}
+	n := len(l)
+	if n >= 2 && knownOS[l[n-2]] && knownArch[l[n-1]] {
+		return l[n-2] == ctxt.GOOS && l[n-1] == ctxt.GOARCH
+	}
+	if n >= 1 && knownOS[l[n-1]] {
+		return l[n-1] == ctxt.GOOS
+	}
+	if n >= 1 && knownArch[l[n-1]] {
+		return l[n-1] == ctxt.GOARCH
+	}
+	return true
+}
+
+var knownOS = make(map[string]bool)
+var knownArch = make(map[string]bool)
+
+func init() {
+	for _, v := range strings.Fields(goosList) {
+		knownOS[v] = true
+	}
+	for _, v := range strings.Fields(goarchList) {
+		knownArch[v] = true
+	}
+}
+
+// ToolDir is the directory containing build tools.
+var ToolDir = filepath.Join(runtime.GOROOT(), "pkg/tool/"+runtime.GOOS+"_"+runtime.GOARCH)
+
+// IsLocalImport reports whether the import path is
+// a local import path, like ".", "..", "./foo", or "../foo".
+func IsLocalImport(path string) bool {
+	return path == "." || path == ".." ||
+		strings.HasPrefix(path, "./") || strings.HasPrefix(path, "../")
+}
 
 // ArchChar returns the architecture character for the given goarch.
 // For example, ArchChar("amd64") returns "6".
diff --git a/libgo/go/go/build/build_test.go b/libgo/go/go/build/build_test.go
index 3c706a46edd..06b8b0e94f8 100644
--- a/libgo/go/go/build/build_test.go
+++ b/libgo/go/go/build/build_test.go
@@ -5,83 +5,14 @@
 package build
 
 import (
+	"os"
 	"path/filepath"
-	"reflect"
 	"runtime"
-	"sort"
 	"testing"
 )
 
-func sortstr(x []string) []string {
-	sort.Strings(x)
-	return x
-}
-
-var buildPkgs = []struct {
-	dir  string
-	info *DirInfo
-}{
-	{
-		"go/build/pkgtest",
-		&DirInfo{
-			GoFiles:      []string{"pkgtest.go"},
-			SFiles:       []string{"sqrt_" + runtime.GOARCH + ".s"},
-			Package:      "pkgtest",
-			Imports:      []string{"bytes"},
-			TestImports:  []string{"fmt", "pkgtest"},
-			TestGoFiles:  sortstr([]string{"sqrt_test.go", "sqrt_" + runtime.GOARCH + "_test.go"}),
-			XTestGoFiles: []string{"xsqrt_test.go"},
-		},
-	},
-	{
-		"go/build/cmdtest",
-		&DirInfo{
-			GoFiles:     []string{"main.go"},
-			Package:     "main",
-			Imports:     []string{"go/build/pkgtest"},
-			TestImports: []string{},
-		},
-	},
-	{
-		"go/build/cgotest",
-		&DirInfo{
-			CgoFiles:    ifCgo([]string{"cgotest.go"}),
-			CFiles:      []string{"cgotest.c"},
-			HFiles:      []string{"cgotest.h"},
-			Imports:     []string{"C", "unsafe"},
-			TestImports: []string{},
-			Package:     "cgotest",
-		},
-	},
-}
-
-func ifCgo(x []string) []string {
-	if DefaultContext.CgoEnabled {
-		return x
-	}
-	return nil
-}
-
-func TestBuild(t *testing.T) {
-	for _, tt := range buildPkgs {
-		tree := Path[0] // Goroot
-		dir := filepath.Join(tree.SrcDir(), tt.dir)
-		info, err := ScanDir(dir)
-		if err != nil {
-			t.Errorf("ScanDir(%#q): %v", tt.dir, err)
-			continue
-		}
-		// Don't bother testing import positions.
-		tt.info.ImportPos, tt.info.TestImportPos = info.ImportPos, info.TestImportPos
-		if !reflect.DeepEqual(info, tt.info) {
-			t.Errorf("ScanDir(%#q) = %#v, want %#v\n", tt.dir, info, tt.info)
-			continue
-		}
-	}
-}
-
 func TestMatch(t *testing.T) {
-	ctxt := DefaultContext
+	ctxt := Default
 	what := "default"
 	match := func(tag string) {
 		if !ctxt.match(tag) {
@@ -106,3 +37,40 @@ func TestMatch(t *testing.T) {
 	match(runtime.GOOS + "," + runtime.GOARCH + ",!bar")
 	nomatch(runtime.GOOS + "," + runtime.GOARCH + ",bar")
 }
+
+func TestDotSlashImport(t *testing.T) {
+	p, err := ImportDir("testdata/other", 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(p.Imports) != 1 || p.Imports[0] != "./file" {
+		t.Fatalf("testdata/other: Imports=%v, want [./file]", p.Imports)
+	}
+
+	p1, err := Import("./file", "testdata/other", 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if p1.Name != "file" {
+		t.Fatalf("./file: Name=%q, want %q", p1.Name, "file")
+	}
+	dir := filepath.Clean("testdata/other/file") // Clean to use \ on Windows
+	if p1.Dir != dir {
+		t.Fatalf("./file: Dir=%q, want %q", p1.Name, dir)
+	}
+}
+
+func TestLocalDirectory(t *testing.T) {
+	cwd, err := os.Getwd()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	p, err := ImportDir(cwd, 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if p.ImportPath != "go/build" {
+		t.Fatalf("ImportPath=%q, want %q", p.ImportPath, "go/build")
+	}
+}
diff --git a/libgo/go/go/build/cgotest/cgotest.go b/libgo/go/go/build/cgotest/cgotest.go
deleted file mode 100644
index 93bbf06883f..00000000000
--- a/libgo/go/go/build/cgotest/cgotest.go
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2011 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 cgotest
-
-/*
-char* greeting = "hello, world";
-*/
-// #include "cgotest.h"
-import "C"
-import "unsafe"
-
-var Greeting = C.GoString(C.greeting)
-
-func DoAdd(x, y int) (sum int) {
-	C.Add(C.int(x), C.int(y), (*C.int)(unsafe.Pointer(&sum)))
-	return
-}
diff --git a/libgo/go/go/build/cmdtest/main.go b/libgo/go/go/build/cmdtest/main.go
deleted file mode 100644
index bed4f485a0a..00000000000
--- a/libgo/go/go/build/cmdtest/main.go
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright 2011 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 main
-
-import "go/build/pkgtest"
-
-func main() {
-	pkgtest.Foo()
-	print(int(pkgtest.Sqrt(9)))
-}
diff --git a/libgo/go/go/build/dir.go b/libgo/go/go/build/dir.go
deleted file mode 100644
index 6b30f76265b..00000000000
--- a/libgo/go/go/build/dir.go
+++ /dev/null
@@ -1,705 +0,0 @@
-// Copyright 2011 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 build
-
-import (
-	"bytes"
-	"errors"
-	"fmt"
-	"go/ast"
-	"go/parser"
-	"go/token"
-	"io/ioutil"
-	"log"
-	"os"
-	"path"
-	"path/filepath"
-	"runtime"
-	"sort"
-	"strconv"
-	"strings"
-	"unicode"
-)
-
-// A Context specifies the supporting context for a build.
-type Context struct {
-	GOARCH      string   // target architecture
-	GOOS        string   // target operating system
-	CgoEnabled  bool     // whether cgo can be used
-	BuildTags   []string // additional tags to recognize in +build lines
-	UseAllFiles bool     // use files regardless of +build lines, file names
-
-	// By default, ScanDir uses the operating system's
-	// file system calls to read directories and files.
-	// Callers can override those calls to provide other
-	// ways to read data by setting ReadDir and ReadFile.
-	// ScanDir does not make any assumptions about the
-	// format of the strings dir and file: they can be
-	// slash-separated, backslash-separated, even URLs.
-
-	// ReadDir returns a slice of os.FileInfo, sorted by Name,
-	// describing the content of the named directory.
-	// The dir argument is the argument to ScanDir.
-	// If ReadDir is nil, ScanDir uses io.ReadDir.
-	ReadDir func(dir string) (fi []os.FileInfo, err error)
-
-	// ReadFile returns the content of the file named file
-	// in the directory named dir.  The dir argument is the
-	// argument to ScanDir, and the file argument is the
-	// Name field from an os.FileInfo returned by ReadDir.
-	// The returned path is the full name of the file, to be
-	// used in error messages.
-	//
-	// If ReadFile is nil, ScanDir uses filepath.Join(dir, file)
-	// as the path and ioutil.ReadFile to read the data.
-	ReadFile func(dir, file string) (path string, content []byte, err error)
-}
-
-func (ctxt *Context) readDir(dir string) ([]os.FileInfo, error) {
-	if f := ctxt.ReadDir; f != nil {
-		return f(dir)
-	}
-	return ioutil.ReadDir(dir)
-}
-
-func (ctxt *Context) readFile(dir, file string) (string, []byte, error) {
-	if f := ctxt.ReadFile; f != nil {
-		return f(dir, file)
-	}
-	p := filepath.Join(dir, file)
-	content, err := ioutil.ReadFile(p)
-	return p, content, err
-}
-
-// The DefaultContext is the default Context for builds.
-// It uses the GOARCH and GOOS environment variables
-// if set, or else the compiled code's GOARCH and GOOS.
-var DefaultContext Context = defaultContext()
-
-var cgoEnabled = map[string]bool{
-	"darwin/386":    true,
-	"darwin/amd64":  true,
-	"linux/386":     true,
-	"linux/amd64":   true,
-	"freebsd/386":   true,
-	"freebsd/amd64": true,
-	"windows/386":   true,
-	"windows/amd64": true,
-}
-
-func defaultContext() Context {
-	var c Context
-
-	c.GOARCH = envOr("GOARCH", runtime.GOARCH)
-	c.GOOS = envOr("GOOS", runtime.GOOS)
-
-	s := os.Getenv("CGO_ENABLED")
-	switch s {
-	case "1":
-		c.CgoEnabled = true
-	case "0":
-		c.CgoEnabled = false
-	default:
-		c.CgoEnabled = cgoEnabled[c.GOOS+"/"+c.GOARCH]
-	}
-
-	return c
-}
-
-func envOr(name, def string) string {
-	s := os.Getenv(name)
-	if s == "" {
-		return def
-	}
-	return s
-}
-
-type DirInfo struct {
-	Package        string                      // Name of package in dir
-	PackageComment *ast.CommentGroup           // Package comments from GoFiles
-	ImportPath     string                      // Import path of package in dir
-	Imports        []string                    // All packages imported by GoFiles
-	ImportPos      map[string][]token.Position // Source code location of imports
-
-	// Source files
-	GoFiles  []string // .go files in dir (excluding CgoFiles, TestGoFiles, XTestGoFiles)
-	HFiles   []string // .h files in dir
-	CFiles   []string // .c files in dir
-	SFiles   []string // .s (and, when using cgo, .S files in dir)
-	CgoFiles []string // .go files that import "C"
-
-	// Cgo directives
-	CgoPkgConfig []string // Cgo pkg-config directives
-	CgoCFLAGS    []string // Cgo CFLAGS directives
-	CgoLDFLAGS   []string // Cgo LDFLAGS directives
-
-	// Test information
-	TestGoFiles   []string // _test.go files in package
-	XTestGoFiles  []string // _test.go files outside package
-	TestImports   []string // All packages imported by (X)TestGoFiles
-	TestImportPos map[string][]token.Position
-}
-
-func (d *DirInfo) IsCommand() bool {
-	// TODO(rsc): This is at least a little bogus.
-	return d.Package == "main"
-}
-
-// ScanDir calls DefaultContext.ScanDir.
-func ScanDir(dir string) (info *DirInfo, err error) {
-	return DefaultContext.ScanDir(dir)
-}
-
-// TODO(rsc): Move this comment to a more appropriate place.
-
-// ScanDir returns a structure with details about the Go package
-// found in the given directory.
-//
-// Most .go, .c, .h, and .s files in the directory are considered part
-// of the package.  The exceptions are:
-//
-//	- .go files in package main (unless no other package is found)
-//	- .go files in package documentation
-//	- files starting with _ or .
-//	- files with build constraints not satisfied by the context
-//
-// Build Constraints
-//
-// A build constraint is a line comment beginning with the directive +build
-// that lists the conditions under which a file should be included in the package.
-// Constraints may appear in any kind of source file (not just Go), but
-// they must be appear near the top of the file, preceded
-// only by blank lines and other line comments.
-//
-// A build constraint is evaluated as the OR of space-separated options;
-// each option evaluates as the AND of its comma-separated terms;
-// and each term is an alphanumeric word or, preceded by !, its negation.
-// That is, the build constraint:
-//
-//	// +build linux,386 darwin,!cgo
-//
-// corresponds to the boolean formula:
-//
-//	(linux AND 386) OR (darwin AND (NOT cgo))
-//
-// During a particular build, the following words are satisfied:
-//
-//	- the target operating system, as spelled by runtime.GOOS
-//	- the target architecture, as spelled by runtime.GOARCH
-//	- "cgo", if ctxt.CgoEnabled is true
-//	- any additional words listed in ctxt.BuildTags
-//
-// If a file's name, after stripping the extension and a possible _test suffix,
-// matches *_GOOS, *_GOARCH, or *_GOOS_GOARCH for any known operating
-// system and architecture values, then the file is considered to have an implicit
-// build constraint requiring those terms.
-//
-// Examples
-//
-// To keep a file from being considered for the build:
-//
-//	// +build ignore
-//
-// (any other unsatisfied word will work as well, but ``ignore'' is conventional.)
-//
-// To build a file only when using cgo, and only on Linux and OS X:
-//
-//	// +build linux,cgo darwin,cgo
-// 
-// Such a file is usually paired with another file implementing the
-// default functionality for other systems, which in this case would
-// carry the constraint:
-//
-//	// +build !linux !darwin !cgo
-//
-// Naming a file dns_windows.go will cause it to be included only when
-// building the package for Windows; similarly, math_386.s will be included
-// only when building the package for 32-bit x86.
-//
-func (ctxt *Context) ScanDir(dir string) (info *DirInfo, err error) {
-	dirs, err := ctxt.readDir(dir)
-	if err != nil {
-		return nil, err
-	}
-
-	var Sfiles []string // files with ".S" (capital S)
-	var di DirInfo
-	var firstFile string
-	imported := make(map[string][]token.Position)
-	testImported := make(map[string][]token.Position)
-	fset := token.NewFileSet()
-	for _, d := range dirs {
-		if d.IsDir() {
-			continue
-		}
-		name := d.Name()
-		if strings.HasPrefix(name, "_") ||
-			strings.HasPrefix(name, ".") {
-			continue
-		}
-		if !ctxt.UseAllFiles && !ctxt.goodOSArchFile(name) {
-			continue
-		}
-
-		ext := path.Ext(name)
-		switch ext {
-		case ".go", ".c", ".s", ".h", ".S":
-			// tentatively okay
-		default:
-			// skip
-			continue
-		}
-
-		filename, data, err := ctxt.readFile(dir, name)
-		if err != nil {
-			return nil, err
-		}
-
-		// Look for +build comments to accept or reject the file.
-		if !ctxt.UseAllFiles && !ctxt.shouldBuild(data) {
-			continue
-		}
-
-		// Going to save the file.  For non-Go files, can stop here.
-		switch ext {
-		case ".c":
-			di.CFiles = append(di.CFiles, name)
-			continue
-		case ".h":
-			di.HFiles = append(di.HFiles, name)
-			continue
-		case ".s":
-			di.SFiles = append(di.SFiles, name)
-			continue
-		case ".S":
-			Sfiles = append(Sfiles, name)
-			continue
-		}
-
-		pf, err := parser.ParseFile(fset, filename, data, parser.ImportsOnly|parser.ParseComments)
-		if err != nil {
-			return nil, err
-		}
-
-		pkg := string(pf.Name.Name)
-		if pkg == "documentation" {
-			continue
-		}
-
-		isTest := strings.HasSuffix(name, "_test.go")
-		if isTest && strings.HasSuffix(pkg, "_test") {
-			pkg = pkg[:len(pkg)-len("_test")]
-		}
-
-		if di.Package == "" {
-			di.Package = pkg
-			firstFile = name
-		} else if pkg != di.Package {
-			return nil, fmt.Errorf("%s: found packages %s (%s) and %s (%s)", dir, di.Package, firstFile, pkg, name)
-		}
-		if pf.Doc != nil {
-			if di.PackageComment != nil {
-				di.PackageComment.List = append(di.PackageComment.List, pf.Doc.List...)
-			} else {
-				di.PackageComment = pf.Doc
-			}
-		}
-
-		// Record imports and information about cgo.
-		isCgo := false
-		for _, decl := range pf.Decls {
-			d, ok := decl.(*ast.GenDecl)
-			if !ok {
-				continue
-			}
-			for _, dspec := range d.Specs {
-				spec, ok := dspec.(*ast.ImportSpec)
-				if !ok {
-					continue
-				}
-				quoted := string(spec.Path.Value)
-				path, err := strconv.Unquote(quoted)
-				if err != nil {
-					log.Panicf("%s: parser returned invalid quoted string: <%s>", filename, quoted)
-				}
-				if isTest {
-					testImported[path] = append(testImported[path], fset.Position(spec.Pos()))
-				} else {
-					imported[path] = append(imported[path], fset.Position(spec.Pos()))
-				}
-				if path == "C" {
-					if isTest {
-						return nil, fmt.Errorf("%s: use of cgo in test not supported", filename)
-					}
-					cg := spec.Doc
-					if cg == nil && len(d.Specs) == 1 {
-						cg = d.Doc
-					}
-					if cg != nil {
-						if err := ctxt.saveCgo(filename, &di, cg); err != nil {
-							return nil, err
-						}
-					}
-					isCgo = true
-				}
-			}
-		}
-		if isCgo {
-			if ctxt.CgoEnabled {
-				di.CgoFiles = append(di.CgoFiles, name)
-			}
-		} else if isTest {
-			if pkg == string(pf.Name.Name) {
-				di.TestGoFiles = append(di.TestGoFiles, name)
-			} else {
-				di.XTestGoFiles = append(di.XTestGoFiles, name)
-			}
-		} else {
-			di.GoFiles = append(di.GoFiles, name)
-		}
-	}
-	if di.Package == "" {
-		return nil, fmt.Errorf("%s: no Go source files", dir)
-	}
-	di.Imports = make([]string, len(imported))
-	di.ImportPos = imported
-	i := 0
-	for p := range imported {
-		di.Imports[i] = p
-		i++
-	}
-	di.TestImports = make([]string, len(testImported))
-	di.TestImportPos = testImported
-	i = 0
-	for p := range testImported {
-		di.TestImports[i] = p
-		i++
-	}
-
-	// add the .S files only if we are using cgo
-	// (which means gcc will compile them).
-	// The standard assemblers expect .s files.
-	if len(di.CgoFiles) > 0 {
-		di.SFiles = append(di.SFiles, Sfiles...)
-		sort.Strings(di.SFiles)
-	}
-
-	// File name lists are sorted because ReadDir sorts.
-	sort.Strings(di.Imports)
-	sort.Strings(di.TestImports)
-	return &di, nil
-}
-
-var slashslash = []byte("//")
-
-// shouldBuild reports whether it is okay to use this file,
-// The rule is that in the file's leading run of // comments
-// and blank lines, which must be followed by a blank line
-// (to avoid including a Go package clause doc comment),
-// lines beginning with '// +build' are taken as build directives.
-//
-// The file is accepted only if each such line lists something
-// matching the file.  For example:
-//
-//	// +build windows linux
-//
-// marks the file as applicable only on Windows and Linux.
-//
-func (ctxt *Context) shouldBuild(content []byte) bool {
-	// Pass 1. Identify leading run of // comments and blank lines,
-	// which must be followed by a blank line.
-	end := 0
-	p := content
-	for len(p) > 0 {
-		line := p
-		if i := bytes.IndexByte(line, '\n'); i >= 0 {
-			line, p = line[:i], p[i+1:]
-		} else {
-			p = p[len(p):]
-		}
-		line = bytes.TrimSpace(line)
-		if len(line) == 0 { // Blank line
-			end = cap(content) - cap(line) // &line[0] - &content[0]
-			continue
-		}
-		if !bytes.HasPrefix(line, slashslash) { // Not comment line
-			break
-		}
-	}
-	content = content[:end]
-
-	// Pass 2.  Process each line in the run.
-	p = content
-	for len(p) > 0 {
-		line := p
-		if i := bytes.IndexByte(line, '\n'); i >= 0 {
-			line, p = line[:i], p[i+1:]
-		} else {
-			p = p[len(p):]
-		}
-		line = bytes.TrimSpace(line)
-		if bytes.HasPrefix(line, slashslash) {
-			line = bytes.TrimSpace(line[len(slashslash):])
-			if len(line) > 0 && line[0] == '+' {
-				// Looks like a comment +line.
-				f := strings.Fields(string(line))
-				if f[0] == "+build" {
-					ok := false
-					for _, tok := range f[1:] {
-						if ctxt.match(tok) {
-							ok = true
-							break
-						}
-					}
-					if !ok {
-						return false // this one doesn't match
-					}
-				}
-			}
-		}
-	}
-	return true // everything matches
-}
-
-// saveCgo saves the information from the #cgo lines in the import "C" comment.
-// These lines set CFLAGS and LDFLAGS and pkg-config directives that affect
-// the way cgo's C code is built.
-//
-// TODO(rsc): This duplicates code in cgo.
-// Once the dust settles, remove this code from cgo.
-func (ctxt *Context) saveCgo(filename string, di *DirInfo, cg *ast.CommentGroup) error {
-	text := cg.Text()
-	for _, line := range strings.Split(text, "\n") {
-		orig := line
-
-		// Line is
-		//	#cgo [GOOS/GOARCH...] LDFLAGS: stuff
-		//
-		line = strings.TrimSpace(line)
-		if len(line) < 5 || line[:4] != "#cgo" || (line[4] != ' ' && line[4] != '\t') {
-			continue
-		}
-
-		// Split at colon.
-		line = strings.TrimSpace(line[4:])
-		i := strings.Index(line, ":")
-		if i < 0 {
-			return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
-		}
-		line, argstr := line[:i], line[i+1:]
-
-		// Parse GOOS/GOARCH stuff.
-		f := strings.Fields(line)
-		if len(f) < 1 {
-			return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
-		}
-
-		cond, verb := f[:len(f)-1], f[len(f)-1]
-		if len(cond) > 0 {
-			ok := false
-			for _, c := range cond {
-				if ctxt.match(c) {
-					ok = true
-					break
-				}
-			}
-			if !ok {
-				continue
-			}
-		}
-
-		args, err := splitQuoted(argstr)
-		if err != nil {
-			return fmt.Errorf("%s: invalid #cgo line: %s", filename, orig)
-		}
-		for _, arg := range args {
-			if !safeName(arg) {
-				return fmt.Errorf("%s: malformed #cgo argument: %s", filename, arg)
-			}
-		}
-
-		switch verb {
-		case "CFLAGS":
-			di.CgoCFLAGS = append(di.CgoCFLAGS, args...)
-		case "LDFLAGS":
-			di.CgoLDFLAGS = append(di.CgoLDFLAGS, args...)
-		case "pkg-config":
-			di.CgoPkgConfig = append(di.CgoPkgConfig, args...)
-		default:
-			return fmt.Errorf("%s: invalid #cgo verb: %s", filename, orig)
-		}
-	}
-	return nil
-}
-
-var safeBytes = []byte("+-.,/0123456789=ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz:")
-
-func safeName(s string) bool {
-	if s == "" {
-		return false
-	}
-	for i := 0; i < len(s); i++ {
-		if c := s[i]; c < 0x80 && bytes.IndexByte(safeBytes, c) < 0 {
-			return false
-		}
-	}
-	return true
-}
-
-// splitQuoted splits the string s around each instance of one or more consecutive
-// white space characters while taking into account quotes and escaping, and
-// returns an array of substrings of s or an empty list if s contains only white space.
-// Single quotes and double quotes are recognized to prevent splitting within the
-// quoted region, and are removed from the resulting substrings. If a quote in s
-// isn't closed err will be set and r will have the unclosed argument as the
-// last element.  The backslash is used for escaping.
-//
-// For example, the following string:
-//
-//     a b:"c d" 'e''f'  "g\""
-//
-// Would be parsed as:
-//
-//     []string{"a", "b:c d", "ef", `g"`}
-//
-func splitQuoted(s string) (r []string, err error) {
-	var args []string
-	arg := make([]rune, len(s))
-	escaped := false
-	quoted := false
-	quote := '\x00'
-	i := 0
-	for _, rune := range s {
-		switch {
-		case escaped:
-			escaped = false
-		case rune == '\\':
-			escaped = true
-			continue
-		case quote != '\x00':
-			if rune == quote {
-				quote = '\x00'
-				continue
-			}
-		case rune == '"' || rune == '\'':
-			quoted = true
-			quote = rune
-			continue
-		case unicode.IsSpace(rune):
-			if quoted || i > 0 {
-				quoted = false
-				args = append(args, string(arg[:i]))
-				i = 0
-			}
-			continue
-		}
-		arg[i] = rune
-		i++
-	}
-	if quoted || i > 0 {
-		args = append(args, string(arg[:i]))
-	}
-	if quote != 0 {
-		err = errors.New("unclosed quote")
-	} else if escaped {
-		err = errors.New("unfinished escaping")
-	}
-	return args, err
-}
-
-// match returns true if the name is one of:
-//
-//	$GOOS
-//	$GOARCH
-//	cgo (if cgo is enabled)
-//	!cgo (if cgo is disabled)
-//	tag (if tag is listed in ctxt.BuildTags)
-//	!tag (if tag is not listed in ctxt.BuildTags)
-//	a slash-separated list of any of these
-//
-func (ctxt *Context) match(name string) bool {
-	if name == "" {
-		return false
-	}
-	if i := strings.Index(name, ","); i >= 0 {
-		// comma-separated list
-		return ctxt.match(name[:i]) && ctxt.match(name[i+1:])
-	}
-	if strings.HasPrefix(name, "!!") { // bad syntax, reject always
-		return false
-	}
-	if strings.HasPrefix(name, "!") { // negation
-		return !ctxt.match(name[1:])
-	}
-
-	// Tags must be letters, digits, underscores.
-	// Unlike in Go identifiers, all digits is fine (e.g., "386").
-	for _, c := range name {
-		if !unicode.IsLetter(c) && !unicode.IsDigit(c) && c != '_' {
-			return false
-		}
-	}
-
-	// special tags
-	if ctxt.CgoEnabled && name == "cgo" {
-		return true
-	}
-	if name == ctxt.GOOS || name == ctxt.GOARCH {
-		return true
-	}
-
-	// other tags
-	for _, tag := range ctxt.BuildTags {
-		if tag == name {
-			return true
-		}
-	}
-
-	return false
-}
-
-// goodOSArchFile returns false if the name contains a $GOOS or $GOARCH
-// suffix which does not match the current system.
-// The recognized name formats are:
-//
-//     name_$(GOOS).*
-//     name_$(GOARCH).*
-//     name_$(GOOS)_$(GOARCH).*
-//     name_$(GOOS)_test.*
-//     name_$(GOARCH)_test.*
-//     name_$(GOOS)_$(GOARCH)_test.*
-//
-func (ctxt *Context) goodOSArchFile(name string) bool {
-	if dot := strings.Index(name, "."); dot != -1 {
-		name = name[:dot]
-	}
-	l := strings.Split(name, "_")
-	if n := len(l); n > 0 && l[n-1] == "test" {
-		l = l[:n-1]
-	}
-	n := len(l)
-	if n >= 2 && knownOS[l[n-2]] && knownArch[l[n-1]] {
-		return l[n-2] == ctxt.GOOS && l[n-1] == ctxt.GOARCH
-	}
-	if n >= 1 && knownOS[l[n-1]] {
-		return l[n-1] == ctxt.GOOS
-	}
-	if n >= 1 && knownArch[l[n-1]] {
-		return l[n-1] == ctxt.GOARCH
-	}
-	return true
-}
-
-var knownOS = make(map[string]bool)
-var knownArch = make(map[string]bool)
-
-func init() {
-	for _, v := range strings.Fields(goosList) {
-		knownOS[v] = true
-	}
-	for _, v := range strings.Fields(goarchList) {
-		knownArch[v] = true
-	}
-}
diff --git a/libgo/go/go/build/doc.go b/libgo/go/go/build/doc.go
new file mode 100644
index 00000000000..67c26ac7f4f
--- /dev/null
+++ b/libgo/go/go/build/doc.go
@@ -0,0 +1,109 @@
+// Copyright 2011 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 build gathers information about Go packages.
+//
+// Go Path
+//
+// The Go path is a list of directory trees containing Go source code.
+// It is consulted to resolve imports that cannot be found in the standard
+// Go tree.  The default path is the value of the GOPATH environment
+// variable, interpreted as a path list appropriate to the operating system
+// (on Unix, the variable is a colon-separated string;
+// on Windows, a semicolon-separated string;
+// on Plan 9, a list).
+//
+// Each directory listed in the Go path must have a prescribed structure:
+//
+// The src/ directory holds source code.  The path below 'src' determines
+// the import path or executable name.
+//
+// The pkg/ directory holds installed package objects.
+// As in the Go tree, each target operating system and
+// architecture pair has its own subdirectory of pkg
+// (pkg/GOOS_GOARCH).
+// 
+// If DIR is a directory listed in the Go path, a package with
+// source in DIR/src/foo/bar can be imported as "foo/bar" and
+// has its compiled form installed to "DIR/pkg/GOOS_GOARCH/foo/bar.a"
+// (or, for gccgo, "DIR/pkg/gccgo/foo/libbar.a").
+// 
+// The bin/ directory holds compiled commands.
+// Each command is named for its source directory, but only
+// using the final element, not the entire path.  That is, the
+// command with source in DIR/src/foo/quux is installed into
+// DIR/bin/quux, not DIR/bin/foo/quux.  The foo/ is stripped
+// so that you can add DIR/bin to your PATH to get at the
+// installed commands.
+// 
+// Here's an example directory layout:
+// 
+//	GOPATH=/home/user/gocode
+// 
+//	/home/user/gocode/
+//	    src/
+//	        foo/
+//	            bar/               (go code in package bar)
+//	                x.go
+//	            quux/              (go code in package main)
+//	                y.go
+//	    bin/
+//	        quux                   (installed command)
+//	    pkg/
+//	        linux_amd64/
+//	            foo/
+//	                bar.a          (installed package object)
+//
+// Build Constraints
+//
+// A build constraint is a line comment beginning with the directive +build
+// that lists the conditions under which a file should be included in the package.
+// Constraints may appear in any kind of source file (not just Go), but
+// they must be appear near the top of the file, preceded
+// only by blank lines and other line comments.
+//
+// A build constraint is evaluated as the OR of space-separated options;
+// each option evaluates as the AND of its comma-separated terms;
+// and each term is an alphanumeric word or, preceded by !, its negation.
+// That is, the build constraint:
+//
+//	// +build linux,386 darwin,!cgo
+//
+// corresponds to the boolean formula:
+//
+//	(linux AND 386) OR (darwin AND (NOT cgo))
+//
+// During a particular build, the following words are satisfied:
+//
+//	- the target operating system, as spelled by runtime.GOOS
+//	- the target architecture, as spelled by runtime.GOARCH
+//	- "cgo", if ctxt.CgoEnabled is true
+//	- any additional words listed in ctxt.BuildTags
+//
+// If a file's name, after stripping the extension and a possible _test suffix,
+// matches *_GOOS, *_GOARCH, or *_GOOS_GOARCH for any known operating
+// system and architecture values, then the file is considered to have an implicit
+// build constraint requiring those terms.
+//
+// To keep a file from being considered for the build:
+//
+//	// +build ignore
+//
+// (any other unsatisfied word will work as well, but ``ignore'' is conventional.)
+//
+// To build a file only when using cgo, and only on Linux and OS X:
+//
+//	// +build linux,cgo darwin,cgo
+//
+// Such a file is usually paired with another file implementing the
+// default functionality for other systems, which in this case would
+// carry the constraint:
+//
+//	// +build !linux !darwin !cgo
+//
+// Naming a file dns_windows.go will cause it to be included only when
+// building the package for Windows; similarly, math_386.s will be included
+// only when building the package for 32-bit x86.
+//
+package build
diff --git a/libgo/go/go/build/path.go b/libgo/go/go/build/path.go
deleted file mode 100644
index e160ac3b280..00000000000
--- a/libgo/go/go/build/path.go
+++ /dev/null
@@ -1,182 +0,0 @@
-// Copyright 2011 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 build
-
-import (
-	"errors"
-	"fmt"
-	"os"
-	"path/filepath"
-	"runtime"
-)
-
-// ToolDir is the directory containing build tools.
-var ToolDir = filepath.Join(runtime.GOROOT(), "pkg/tool/"+runtime.GOOS+"_"+runtime.GOARCH)
-
-// Path is a validated list of Trees derived from $GOROOT and $GOPATH at init.
-var Path []*Tree
-
-// Tree describes a Go source tree, either $GOROOT or one from $GOPATH.
-type Tree struct {
-	Path   string
-	Goroot bool
-}
-
-func newTree(p string) (*Tree, error) {
-	if !filepath.IsAbs(p) {
-		return nil, errors.New("must be absolute")
-	}
-	ep, err := filepath.EvalSymlinks(p)
-	if err != nil {
-		return nil, err
-	}
-	return &Tree{Path: ep}, nil
-}
-
-// SrcDir returns the tree's package source directory.
-func (t *Tree) SrcDir() string {
-	if t.Goroot {
-		return filepath.Join(t.Path, "src", "pkg")
-	}
-	return filepath.Join(t.Path, "src")
-}
-
-// PkgDir returns the tree's package object directory.
-func (t *Tree) PkgDir() string {
-	goos, goarch := runtime.GOOS, runtime.GOARCH
-	if e := os.Getenv("GOOS"); e != "" {
-		goos = e
-	}
-	if e := os.Getenv("GOARCH"); e != "" {
-		goarch = e
-	}
-	return filepath.Join(t.Path, "pkg", goos+"_"+goarch)
-}
-
-// BinDir returns the tree's binary executable directory.
-func (t *Tree) BinDir() string {
-	if t.Goroot {
-		if gobin := os.Getenv("GOBIN"); gobin != "" {
-			return filepath.Clean(gobin)
-		}
-	}
-	return filepath.Join(t.Path, "bin")
-}
-
-// HasSrc returns whether the given package's
-// source can be found inside this Tree.
-func (t *Tree) HasSrc(pkg string) bool {
-	fi, err := os.Stat(filepath.Join(t.SrcDir(), pkg))
-	if err != nil {
-		return false
-	}
-	return fi.IsDir()
-}
-
-// HasPkg returns whether the given package's
-// object file can be found inside this Tree.
-func (t *Tree) HasPkg(pkg string) bool {
-	fi, err := os.Stat(filepath.Join(t.PkgDir(), pkg+".a"))
-	if err != nil {
-		return false
-	}
-	return !fi.IsDir()
-}
-
-var (
-	ErrNotFound     = errors.New("package could not be found locally")
-	ErrTreeNotFound = errors.New("no valid GOROOT or GOPATH could be found")
-)
-
-// FindTree takes an import or filesystem path and returns the
-// tree where the package source should be and the package import path.
-func FindTree(path string) (tree *Tree, pkg string, err error) {
-	if isLocalPath(path) {
-		if path, err = filepath.Abs(path); err != nil {
-			return
-		}
-		if path, err = filepath.EvalSymlinks(path); err != nil {
-			return
-		}
-		for _, t := range Path {
-			tpath := t.SrcDir() + string(filepath.Separator)
-			if !filepath.HasPrefix(path, tpath) {
-				continue
-			}
-			tree = t
-			pkg = filepath.ToSlash(path[len(tpath):])
-			return
-		}
-		err = fmt.Errorf("path %q not inside a GOPATH", path)
-		return
-	}
-	tree = defaultTree
-	pkg = filepath.ToSlash(path)
-	for _, t := range Path {
-		if t.HasSrc(pkg) {
-			tree = t
-			return
-		}
-	}
-	if tree == nil {
-		err = ErrTreeNotFound
-	} else {
-		err = ErrNotFound
-	}
-	return
-}
-
-// isLocalPath returns whether the given path is local (/foo ./foo ../foo . ..)
-// Windows paths that starts with drive letter (c:\foo c:foo) are considered local.
-func isLocalPath(s string) bool {
-	const sep = string(filepath.Separator)
-	return s == "." || s == ".." ||
-		filepath.HasPrefix(s, sep) ||
-		filepath.HasPrefix(s, "."+sep) || filepath.HasPrefix(s, ".."+sep) ||
-		filepath.VolumeName(s) != ""
-}
-
-var (
-	// argument lists used by the build's gc and ld methods
-	gcImportArgs []string
-	ldImportArgs []string
-
-	// default tree for remote packages
-	defaultTree *Tree
-)
-
-// set up Path: parse and validate GOROOT and GOPATH variables
-func init() {
-	root := runtime.GOROOT()
-	t, err := newTree(root)
-	if err == nil {
-		t.Goroot = true
-		Path = []*Tree{t}
-	}
-
-	for _, p := range filepath.SplitList(os.Getenv("GOPATH")) {
-		if p == "" {
-			continue
-		}
-		t, err := newTree(p)
-		if err != nil {
-			continue
-		}
-
-		Path = append(Path, t)
-		gcImportArgs = append(gcImportArgs, "-I", t.PkgDir())
-		ldImportArgs = append(ldImportArgs, "-L", t.PkgDir())
-
-		// select first GOPATH entry as default
-		if defaultTree == nil {
-			defaultTree = t
-		}
-	}
-
-	// use GOROOT if no valid GOPATH specified
-	if defaultTree == nil && len(Path) > 0 {
-		defaultTree = Path[0]
-	}
-}
diff --git a/libgo/go/go/build/pkgtest/pkgtest.go b/libgo/go/go/build/pkgtest/pkgtest.go
deleted file mode 100644
index 08eea1e2bc3..00000000000
--- a/libgo/go/go/build/pkgtest/pkgtest.go
+++ /dev/null
@@ -1,13 +0,0 @@
-// Copyright 2011 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 pkgtest
-
-import "bytes"
-
-func Foo() *bytes.Buffer {
-	return nil
-}
-
-func Sqrt(x float64) float64
diff --git a/libgo/go/go/build/pkgtest/sqrt_386_test.go b/libgo/go/go/build/pkgtest/sqrt_386_test.go
deleted file mode 100644
index 26b483fa0ba..00000000000
--- a/libgo/go/go/build/pkgtest/sqrt_386_test.go
+++ /dev/null
@@ -1 +0,0 @@
-package pkgtest
diff --git a/libgo/go/go/build/pkgtest/sqrt_amd64_test.go b/libgo/go/go/build/pkgtest/sqrt_amd64_test.go
deleted file mode 100644
index 26b483fa0ba..00000000000
--- a/libgo/go/go/build/pkgtest/sqrt_amd64_test.go
+++ /dev/null
@@ -1 +0,0 @@
-package pkgtest
diff --git a/libgo/go/go/build/pkgtest/sqrt_arm_test.go b/libgo/go/go/build/pkgtest/sqrt_arm_test.go
deleted file mode 100644
index 26b483fa0ba..00000000000
--- a/libgo/go/go/build/pkgtest/sqrt_arm_test.go
+++ /dev/null
@@ -1 +0,0 @@
-package pkgtest
diff --git a/libgo/go/go/build/pkgtest/sqrt_test.go b/libgo/go/go/build/pkgtest/sqrt_test.go
deleted file mode 100644
index ee9fd5de688..00000000000
--- a/libgo/go/go/build/pkgtest/sqrt_test.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2011 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 pkgtest
-
-import "fmt"
-
-var _ = fmt.Printf
diff --git a/libgo/go/go/build/pkgtest/xsqrt_test.go b/libgo/go/go/build/pkgtest/xsqrt_test.go
deleted file mode 100644
index 3898d1dda59..00000000000
--- a/libgo/go/go/build/pkgtest/xsqrt_test.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2011 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 pkgtest_test
-
-import "pkgtest"
-
-var _ = pkgtest.Foo
diff --git a/libgo/go/go/build/syslist_test.go b/libgo/go/go/build/syslist_test.go
index d27630d758d..9157faf8cb9 100644
--- a/libgo/go/go/build/syslist_test.go
+++ b/libgo/go/go/build/syslist_test.go
@@ -55,7 +55,7 @@ var tests = []GoodFileTest{
 
 func TestGoodOSArch(t *testing.T) {
 	for _, test := range tests {
-		if DefaultContext.goodOSArchFile(test.name) != test.result {
+		if Default.goodOSArchFile(test.name) != test.result {
 			t.Fatalf("goodOSArchFile(%q) != %v", test.name, test.result)
 		}
 	}
diff --git a/libgo/go/go/build/testdata/other/file/file.go b/libgo/go/go/build/testdata/other/file/file.go
new file mode 100644
index 00000000000..bbfd3e9e598
--- /dev/null
+++ b/libgo/go/go/build/testdata/other/file/file.go
@@ -0,0 +1,5 @@
+// Test data - not compiled.
+
+package file
+
+func F() {}
diff --git a/libgo/go/go/build/testdata/other/main.go b/libgo/go/go/build/testdata/other/main.go
new file mode 100644
index 00000000000..e0904357c92
--- /dev/null
+++ b/libgo/go/go/build/testdata/other/main.go
@@ -0,0 +1,11 @@
+// Test data - not compiled.
+
+package main
+
+import (
+	"./file"
+)
+
+func main() {
+	file.F()
+}
diff --git a/libgo/go/go/doc/reader.go b/libgo/go/go/doc/reader.go
index 3558892ebd0..5eaae37b7de 100644
--- a/libgo/go/go/doc/reader.go
+++ b/libgo/go/go/doc/reader.go
@@ -432,6 +432,17 @@ func (r *reader) readFile(src *ast.File) {
 				r.readValue(d)
 			case token.TYPE:
 				// types are handled individually
+				if len(d.Specs) == 1 && !d.Lparen.IsValid() {
+					// common case: single declaration w/o parentheses
+					// (if a single declaration is parenthesized,
+					// create a new fake declaration below, so that
+					// go/doc type declarations always appear w/o
+					// parentheses)
+					if s, ok := d.Specs[0].(*ast.TypeSpec); ok {
+						r.readType(d, s)
+					}
+					break
+				}
 				for _, spec := range d.Specs {
 					if s, ok := spec.(*ast.TypeSpec); ok {
 						// use an individual (possibly fake) declaration
@@ -439,8 +450,13 @@ func (r *reader) readFile(src *ast.File) {
 						// gets to (re-)use the declaration documentation
 						// if there's none associated with the spec itself
 						fake := &ast.GenDecl{
-							Doc:    d.Doc,
-							TokPos: d.Pos(),
+							Doc: d.Doc,
+							// don't use the existing TokPos because it
+							// will lead to the wrong selection range for
+							// the fake declaration if there are more
+							// than one type in the group (this affects
+							// src/cmd/godoc/godoc.go's posLink_urlFunc)
+							TokPos: s.Pos(),
 							Tok:    token.TYPE,
 							Specs:  []ast.Spec{s},
 						}
diff --git a/libgo/go/go/parser/parser.go b/libgo/go/go/parser/parser.go
index c1e61904486..a122baf0879 100644
--- a/libgo/go/go/parser/parser.go
+++ b/libgo/go/go/parser/parser.go
@@ -14,6 +14,9 @@ import (
 	"go/ast"
 	"go/scanner"
 	"go/token"
+	"strconv"
+	"strings"
+	"unicode"
 )
 
 // The parser structure holds the parser's internal state.
@@ -1913,6 +1916,17 @@ func (p *parser) parseStmt() (s ast.Stmt) {
 
 type parseSpecFunction func(p *parser, doc *ast.CommentGroup, iota int) ast.Spec
 
+func isValidImport(lit string) bool {
+	const illegalChars = `!"#$%&'()*,:;<=>?[\]^{|}` + "`\uFFFD"
+	s, _ := strconv.Unquote(lit) // go/scanner returns a legal string literal
+	for _, r := range s {
+		if !unicode.IsGraphic(r) || unicode.IsSpace(r) || strings.ContainsRune(illegalChars, r) {
+			return false
+		}
+	}
+	return s != ""
+}
+
 func parseImportSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec {
 	if p.trace {
 		defer un(trace(p, "ImportSpec"))
@@ -1929,6 +1943,9 @@ func parseImportSpec(p *parser, doc *ast.CommentGroup, _ int) ast.Spec {
 
 	var path *ast.BasicLit
 	if p.tok == token.STRING {
+		if !isValidImport(p.lit) {
+			p.error(p.pos, "invalid import path: "+p.lit)
+		}
 		path = &ast.BasicLit{ValuePos: p.pos, Kind: p.tok, Value: p.lit}
 		p.next()
 	} else {
diff --git a/libgo/go/go/parser/parser_test.go b/libgo/go/go/parser/parser_test.go
index a3ee8525de2..93ca3d6aa39 100644
--- a/libgo/go/go/parser/parser_test.go
+++ b/libgo/go/go/parser/parser_test.go
@@ -5,6 +5,7 @@
 package parser
 
 import (
+	"fmt"
 	"go/ast"
 	"go/token"
 	"os"
@@ -204,3 +205,48 @@ func TestVarScope(t *testing.T) {
 		}
 	}
 }
+
+var imports = map[string]bool{
+	`"a"`:        true,
+	"`a`":        true,
+	`"a/b"`:      true,
+	`"a.b"`:      true,
+	`"m\x61th"`:  true,
+	`"greek/αβ"`: true,
+	`""`:         false,
+
+	// Each of these pairs tests both `` vs "" strings
+	// and also use of invalid characters spelled out as
+	// escape sequences and written directly.
+	// For example `"\x00"` tests import "\x00"
+	// while "`\x00`" tests import `<actual-NUL-byte>`.
+	`"\x00"`:     false,
+	"`\x00`":     false,
+	`"\x7f"`:     false,
+	"`\x7f`":     false,
+	`"a!"`:       false,
+	"`a!`":       false,
+	`"a b"`:      false,
+	"`a b`":      false,
+	`"a\\b"`:     false,
+	"`a\\b`":     false,
+	"\"`a`\"":    false,
+	"`\"a\"`":    false,
+	`"\x80\x80"`: false,
+	"`\x80\x80`": false,
+	`"\xFFFD"`:   false,
+	"`\xFFFD`":   false,
+}
+
+func TestImports(t *testing.T) {
+	for path, isValid := range imports {
+		src := fmt.Sprintf("package p; import %s", path)
+		_, err := ParseFile(fset, "", src, 0)
+		switch {
+		case err != nil && isValid:
+			t.Errorf("ParseFile(%s): got %v; expected no error", src, err)
+		case err == nil && !isValid:
+			t.Errorf("ParseFile(%s): got no error; expected one", src)
+		}
+	}
+}
diff --git a/libgo/go/go/printer/nodes.go b/libgo/go/go/printer/nodes.go
index cd5e075c16c..05b4ef59a2d 100644
--- a/libgo/go/go/printer/nodes.go
+++ b/libgo/go/go/printer/nodes.go
@@ -12,6 +12,7 @@ import (
 	"bytes"
 	"go/ast"
 	"go/token"
+	"unicode/utf8"
 )
 
 // Other formatting issues:
@@ -82,46 +83,37 @@ func (p *printer) setComment(g *ast.CommentGroup) {
 type exprListMode uint
 
 const (
-	blankStart exprListMode = 1 << iota // print a blank before a non-empty list
-	blankEnd                            // print a blank after a non-empty list
-	commaSep                            // elements are separated by commas
-	commaTerm                           // list is optionally terminated by a comma
-	noIndent                            // no extra indentation in multi-line lists
+	commaTerm exprListMode = 1 << iota // list is optionally terminated by a comma
+	noIndent                           // no extra indentation in multi-line lists
 )
 
-// Sets multiLine to true if the identifier list spans multiple lines.
 // If indent is set, a multi-line identifier list is indented after the
 // first linebreak encountered.
-func (p *printer) identList(list []*ast.Ident, indent bool, multiLine *bool) {
+func (p *printer) identList(list []*ast.Ident, indent bool) {
 	// convert into an expression list so we can re-use exprList formatting
 	xlist := make([]ast.Expr, len(list))
 	for i, x := range list {
 		xlist[i] = x
 	}
-	mode := commaSep
+	var mode exprListMode
 	if !indent {
-		mode |= noIndent
+		mode = noIndent
 	}
-	p.exprList(token.NoPos, xlist, 1, mode, multiLine, token.NoPos)
+	p.exprList(token.NoPos, xlist, 1, mode, token.NoPos)
 }
 
 // Print a list of expressions. If the list spans multiple
 // source lines, the original line breaks are respected between
-// expressions. Sets multiLine to true if the list spans multiple
-// lines.
+// expressions.
 //
 // TODO(gri) Consider rewriting this to be independent of []ast.Expr
 //           so that we can use the algorithm for any kind of list
 //           (e.g., pass list via a channel over which to range).
-func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exprListMode, multiLine *bool, next0 token.Pos) {
+func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exprListMode, next0 token.Pos) {
 	if len(list) == 0 {
 		return
 	}
 
-	if mode&blankStart != 0 {
-		p.print(blank)
-	}
-
 	prev := p.posFor(prev0)
 	next := p.posFor(next0)
 	line := p.lineFor(list[0].Pos())
@@ -131,17 +123,11 @@ func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exp
 		// all list entries on a single line
 		for i, x := range list {
 			if i > 0 {
-				if mode&commaSep != 0 {
-					// use position of expression following the comma as
-					// comma position for correct comment placement
-					p.print(x.Pos(), token.COMMA)
-				}
-				p.print(blank)
+				// use position of expression following the comma as
+				// comma position for correct comment placement
+				p.print(x.Pos(), token.COMMA, blank)
 			}
-			p.expr0(x, depth, multiLine)
-		}
-		if mode&blankEnd != 0 {
-			p.print(blank)
+			p.expr0(x, depth)
 		}
 		return
 	}
@@ -161,7 +147,6 @@ func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exp
 	prevBreak := -1 // index of last expression that was followed by a linebreak
 	if prev.IsValid() && prev.Line < line && p.linebreak(line, 0, ws, true) {
 		ws = ignore
-		*multiLine = true
 		prevBreak = 0
 	}
 
@@ -215,15 +200,13 @@ func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exp
 
 		if i > 0 {
 			needsLinebreak := prevLine < line && prevLine > 0 && line > 0
-			if mode&commaSep != 0 {
-				// use position of expression following the comma as
-				// comma position for correct comment placement, but
-				// only if the expression is on the same line
-				if !needsLinebreak {
-					p.print(x.Pos())
-				}
-				p.print(token.COMMA)
+			// use position of expression following the comma as
+			// comma position for correct comment placement, but
+			// only if the expression is on the same line
+			if !needsLinebreak {
+				p.print(x.Pos())
 			}
+			p.print(token.COMMA)
 			needsBlank := true
 			if needsLinebreak {
 				// lines are broken using newlines so comments remain aligned
@@ -231,7 +214,6 @@ func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exp
 				// the same line in which case formfeed is used
 				if p.linebreak(line, 0, ws, useFF || prevBreak+1 < i) {
 					ws = ignore
-					*multiLine = true
 					prevBreak = i
 					needsBlank = false // we got a line break instead
 				}
@@ -245,11 +227,11 @@ func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exp
 			// we have a key:value expression that fits onto one line and
 			// is in a list with more then one entry: use a column for the
 			// key such that consecutive entries can align if possible
-			p.expr(pair.Key, multiLine)
+			p.expr(pair.Key)
 			p.print(pair.Colon, token.COLON, vtab)
-			p.expr(pair.Value, multiLine)
+			p.expr(pair.Value)
 		} else {
-			p.expr0(x, depth, multiLine)
+			p.expr0(x, depth)
 		}
 	}
 
@@ -264,18 +246,13 @@ func (p *printer) exprList(prev0 token.Pos, list []ast.Expr, depth int, mode exp
 		return
 	}
 
-	if mode&blankEnd != 0 {
-		p.print(blank)
-	}
-
 	if ws == ignore && mode&noIndent == 0 {
 		// unindent if we indented
 		p.print(unindent)
 	}
 }
 
-// Sets multiLine to true if the the parameter list spans multiple lines.
-func (p *printer) parameters(fields *ast.FieldList, multiLine *bool) {
+func (p *printer) parameters(fields *ast.FieldList) {
 	p.print(fields.Opening, token.LPAREN)
 	if len(fields.List) > 0 {
 		prevLine := p.lineFor(fields.Opening)
@@ -306,7 +283,6 @@ func (p *printer) parameters(fields *ast.FieldList, multiLine *bool) {
 			if needsLinebreak && p.linebreak(parLineBeg, 0, ws, true) {
 				// break line if the opening "(" or previous parameter ended on a different line
 				ws = ignore
-				*multiLine = true
 			} else if i > 0 {
 				p.print(blank)
 			}
@@ -318,11 +294,11 @@ func (p *printer) parameters(fields *ast.FieldList, multiLine *bool) {
 				// again at the end (and still ws == indent). Thus, a subsequent indent
 				// by a linebreak call after a type, or in the next multi-line identList
 				// will do the right thing.
-				p.identList(par.Names, ws == indent, multiLine)
+				p.identList(par.Names, ws == indent)
 				p.print(blank)
 			}
 			// parameter type
-			p.expr(par.Type, multiLine)
+			p.expr(par.Type)
 			prevLine = parLineEnd
 		}
 		// if the closing ")" is on a separate line from the last parameter,
@@ -339,27 +315,26 @@ func (p *printer) parameters(fields *ast.FieldList, multiLine *bool) {
 	p.print(fields.Closing, token.RPAREN)
 }
 
-// Sets multiLine to true if the signature spans multiple lines.
-func (p *printer) signature(params, result *ast.FieldList, multiLine *bool) {
-	p.parameters(params, multiLine)
+func (p *printer) signature(params, result *ast.FieldList) {
+	p.parameters(params)
 	n := result.NumFields()
 	if n > 0 {
 		p.print(blank)
 		if n == 1 && result.List[0].Names == nil {
 			// single anonymous result; no ()'s
-			p.expr(result.List[0].Type, multiLine)
+			p.expr(result.List[0].Type)
 			return
 		}
-		p.parameters(result, multiLine)
+		p.parameters(result)
 	}
 }
 
 func identListSize(list []*ast.Ident, maxSize int) (size int) {
 	for i, x := range list {
 		if i > 0 {
-			size += 2 // ", "
+			size += len(", ")
 		}
-		size += len(x.Name)
+		size += utf8.RuneCountInString(x.Name)
 		if size >= maxSize {
 			break
 		}
@@ -389,6 +364,10 @@ func (p *printer) setLineComment(text string) {
 	p.setComment(&ast.CommentGroup{List: []*ast.Comment{{Slash: token.NoPos, Text: text}}})
 }
 
+func (p *printer) isMultiLine(n ast.Node) bool {
+	return p.lineFor(n.End())-p.lineFor(n.Pos()) > 1
+}
+
 func (p *printer) fieldList(fields *ast.FieldList, isStruct, isIncomplete bool) {
 	lbrace := fields.Opening
 	list := fields.List
@@ -412,12 +391,12 @@ func (p *printer) fieldList(fields *ast.FieldList, isStruct, isIncomplete bool)
 					// no comments so no need for comma position
 					p.print(token.COMMA, blank)
 				}
-				p.expr(x, ignoreMultiLine)
+				p.expr(x)
 			}
 			if len(f.Names) > 0 {
 				p.print(blank)
 			}
-			p.expr(f.Type, ignoreMultiLine)
+			p.expr(f.Type)
 			p.print(blank, rbrace, token.RBRACE)
 			return
 		}
@@ -435,23 +414,22 @@ func (p *printer) fieldList(fields *ast.FieldList, isStruct, isIncomplete bool)
 		if len(list) == 1 {
 			sep = blank
 		}
-		var ml bool
+		newSection := false
 		for i, f := range list {
 			if i > 0 {
-				p.linebreak(p.lineFor(f.Pos()), 1, ignore, ml)
+				p.linebreak(p.lineFor(f.Pos()), 1, ignore, newSection)
 			}
-			ml = false
 			extraTabs := 0
 			p.setComment(f.Doc)
 			if len(f.Names) > 0 {
 				// named fields
-				p.identList(f.Names, false, &ml)
+				p.identList(f.Names, false)
 				p.print(sep)
-				p.expr(f.Type, &ml)
+				p.expr(f.Type)
 				extraTabs = 1
 			} else {
 				// anonymous field
-				p.expr(f.Type, &ml)
+				p.expr(f.Type)
 				extraTabs = 2
 			}
 			if f.Tag != nil {
@@ -459,7 +437,7 @@ func (p *printer) fieldList(fields *ast.FieldList, isStruct, isIncomplete bool)
 					p.print(sep)
 				}
 				p.print(sep)
-				p.expr(f.Tag, &ml)
+				p.expr(f.Tag)
 				extraTabs = 0
 			}
 			if f.Comment != nil {
@@ -468,6 +446,7 @@ func (p *printer) fieldList(fields *ast.FieldList, isStruct, isIncomplete bool)
 				}
 				p.setComment(f.Comment)
 			}
+			newSection = p.isMultiLine(f)
 		}
 		if isIncomplete {
 			if len(list) > 0 {
@@ -479,22 +458,22 @@ func (p *printer) fieldList(fields *ast.FieldList, isStruct, isIncomplete bool)
 
 	} else { // interface
 
-		var ml bool
+		newSection := false
 		for i, f := range list {
 			if i > 0 {
-				p.linebreak(p.lineFor(f.Pos()), 1, ignore, ml)
+				p.linebreak(p.lineFor(f.Pos()), 1, ignore, newSection)
 			}
-			ml = false
 			p.setComment(f.Doc)
 			if ftyp, isFtyp := f.Type.(*ast.FuncType); isFtyp {
 				// method
-				p.expr(f.Names[0], &ml)
-				p.signature(ftyp.Params, ftyp.Results, &ml)
+				p.expr(f.Names[0])
+				p.signature(ftyp.Params, ftyp.Results)
 			} else {
 				// embedded interface
-				p.expr(f.Type, &ml)
+				p.expr(f.Type)
 			}
 			p.setComment(f.Comment)
+			newSection = p.isMultiLine(f)
 		}
 		if isIncomplete {
 			if len(list) > 0 {
@@ -635,15 +614,14 @@ func reduceDepth(depth int) int {
 //	   cutoff is 6 (always use spaces) in Normal mode
 //	   and 4 (never use spaces) in Compact mode.
 //
-// Sets multiLine to true if the binary expression spans multiple lines.
-func (p *printer) binaryExpr(x *ast.BinaryExpr, prec1, cutoff, depth int, multiLine *bool) {
+func (p *printer) binaryExpr(x *ast.BinaryExpr, prec1, cutoff, depth int) {
 	prec := x.Op.Precedence()
 	if prec < prec1 {
 		// parenthesis needed
 		// Note: The parser inserts an ast.ParenExpr node; thus this case
 		//       can only occur if the AST is created in a different way.
 		p.print(token.LPAREN)
-		p.expr0(x, reduceDepth(depth), multiLine) // parentheses undo one level of depth
+		p.expr0(x, reduceDepth(depth)) // parentheses undo one level of depth
 		p.print(token.RPAREN)
 		return
 	}
@@ -651,7 +629,7 @@ func (p *printer) binaryExpr(x *ast.BinaryExpr, prec1, cutoff, depth int, multiL
 	printBlank := prec < cutoff
 
 	ws := indent
-	p.expr1(x.X, prec, depth+diffPrec(x.X, prec), multiLine)
+	p.expr1(x.X, prec, depth+diffPrec(x.X, prec))
 	if printBlank {
 		p.print(blank)
 	}
@@ -663,14 +641,13 @@ func (p *printer) binaryExpr(x *ast.BinaryExpr, prec1, cutoff, depth int, multiL
 		// in the source
 		if p.linebreak(yline, 1, ws, true) {
 			ws = ignore
-			*multiLine = true
 			printBlank = false // no blank after line break
 		}
 	}
 	if printBlank {
 		p.print(blank)
 	}
-	p.expr1(x.Y, prec+1, depth+1, multiLine)
+	p.expr1(x.Y, prec+1, depth+1)
 	if ws == ignore {
 		p.print(unindent)
 	}
@@ -681,8 +658,7 @@ func isBinary(expr ast.Expr) bool {
 	return ok
 }
 
-// Sets multiLine to true if the expression spans multiple lines.
-func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
+func (p *printer) expr1(expr ast.Expr, prec1, depth int) {
 	p.print(expr.Pos())
 
 	switch x := expr.(type) {
@@ -697,12 +673,12 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 			p.internalError("depth < 1:", depth)
 			depth = 1
 		}
-		p.binaryExpr(x, prec1, cutoff(x, depth), depth, multiLine)
+		p.binaryExpr(x, prec1, cutoff(x, depth), depth)
 
 	case *ast.KeyValueExpr:
-		p.expr(x.Key, multiLine)
+		p.expr(x.Key)
 		p.print(x.Colon, token.COLON, blank)
-		p.expr(x.Value, multiLine)
+		p.expr(x.Value)
 
 	case *ast.StarExpr:
 		const prec = token.UnaryPrec
@@ -710,12 +686,12 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 			// parenthesis needed
 			p.print(token.LPAREN)
 			p.print(token.MUL)
-			p.expr(x.X, multiLine)
+			p.expr(x.X)
 			p.print(token.RPAREN)
 		} else {
 			// no parenthesis needed
 			p.print(token.MUL)
-			p.expr(x.X, multiLine)
+			p.expr(x.X)
 		}
 
 	case *ast.UnaryExpr:
@@ -723,7 +699,7 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 		if prec < prec1 {
 			// parenthesis needed
 			p.print(token.LPAREN)
-			p.expr(x, multiLine)
+			p.expr(x)
 			p.print(token.RPAREN)
 		} else {
 			// no parenthesis needed
@@ -732,42 +708,41 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 				// TODO(gri) Remove this code if it cannot be reached.
 				p.print(blank)
 			}
-			p.expr1(x.X, prec, depth, multiLine)
+			p.expr1(x.X, prec, depth)
 		}
 
 	case *ast.BasicLit:
 		p.print(x)
 
 	case *ast.FuncLit:
-		p.expr(x.Type, multiLine)
-		p.funcBody(x.Body, p.distance(x.Type.Pos(), p.pos), true, multiLine)
+		p.expr(x.Type)
+		p.funcBody(x.Body, p.distance(x.Type.Pos(), p.pos), true)
 
 	case *ast.ParenExpr:
 		if _, hasParens := x.X.(*ast.ParenExpr); hasParens {
 			// don't print parentheses around an already parenthesized expression
 			// TODO(gri) consider making this more general and incorporate precedence levels
-			p.expr0(x.X, reduceDepth(depth), multiLine) // parentheses undo one level of depth
+			p.expr0(x.X, reduceDepth(depth)) // parentheses undo one level of depth
 		} else {
 			p.print(token.LPAREN)
-			p.expr0(x.X, reduceDepth(depth), multiLine) // parentheses undo one level of depth
+			p.expr0(x.X, reduceDepth(depth)) // parentheses undo one level of depth
 			p.print(x.Rparen, token.RPAREN)
 		}
 
 	case *ast.SelectorExpr:
-		p.expr1(x.X, token.HighestPrec, depth, multiLine)
+		p.expr1(x.X, token.HighestPrec, depth)
 		p.print(token.PERIOD)
 		if line := p.lineFor(x.Sel.Pos()); p.pos.IsValid() && p.pos.Line < line {
 			p.print(indent, newline, x.Sel.Pos(), x.Sel, unindent)
-			*multiLine = true
 		} else {
 			p.print(x.Sel.Pos(), x.Sel)
 		}
 
 	case *ast.TypeAssertExpr:
-		p.expr1(x.X, token.HighestPrec, depth, multiLine)
+		p.expr1(x.X, token.HighestPrec, depth)
 		p.print(token.PERIOD, token.LPAREN)
 		if x.Type != nil {
-			p.expr(x.Type, multiLine)
+			p.expr(x.Type)
 		} else {
 			p.print(token.TYPE)
 		}
@@ -775,17 +750,17 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 
 	case *ast.IndexExpr:
 		// TODO(gri): should treat[] like parentheses and undo one level of depth
-		p.expr1(x.X, token.HighestPrec, 1, multiLine)
+		p.expr1(x.X, token.HighestPrec, 1)
 		p.print(x.Lbrack, token.LBRACK)
-		p.expr0(x.Index, depth+1, multiLine)
+		p.expr0(x.Index, depth+1)
 		p.print(x.Rbrack, token.RBRACK)
 
 	case *ast.SliceExpr:
 		// TODO(gri): should treat[] like parentheses and undo one level of depth
-		p.expr1(x.X, token.HighestPrec, 1, multiLine)
+		p.expr1(x.X, token.HighestPrec, 1)
 		p.print(x.Lbrack, token.LBRACK)
 		if x.Low != nil {
-			p.expr0(x.Low, depth+1, multiLine)
+			p.expr0(x.Low, depth+1)
 		}
 		// blanks around ":" if both sides exist and either side is a binary expression
 		if depth <= 1 && x.Low != nil && x.High != nil && (isBinary(x.Low) || isBinary(x.High)) {
@@ -794,7 +769,7 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 			p.print(token.COLON)
 		}
 		if x.High != nil {
-			p.expr0(x.High, depth+1, multiLine)
+			p.expr0(x.High, depth+1)
 		}
 		p.print(x.Rbrack, token.RBRACK)
 
@@ -802,21 +777,26 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 		if len(x.Args) > 1 {
 			depth++
 		}
-		p.expr1(x.Fun, token.HighestPrec, depth, multiLine)
+		p.expr1(x.Fun, token.HighestPrec, depth)
 		p.print(x.Lparen, token.LPAREN)
-		p.exprList(x.Lparen, x.Args, depth, commaSep|commaTerm, multiLine, x.Rparen)
 		if x.Ellipsis.IsValid() {
+			p.exprList(x.Lparen, x.Args, depth, 0, x.Ellipsis)
 			p.print(x.Ellipsis, token.ELLIPSIS)
+			if x.Rparen.IsValid() && p.lineFor(x.Ellipsis) < p.lineFor(x.Rparen) {
+				p.print(token.COMMA, formfeed)
+			}
+		} else {
+			p.exprList(x.Lparen, x.Args, depth, commaTerm, x.Rparen)
 		}
 		p.print(x.Rparen, token.RPAREN)
 
 	case *ast.CompositeLit:
 		// composite literal elements that are composite literals themselves may have the type omitted
 		if x.Type != nil {
-			p.expr1(x.Type, token.HighestPrec, depth, multiLine)
+			p.expr1(x.Type, token.HighestPrec, depth)
 		}
 		p.print(x.Lbrace, token.LBRACE)
-		p.exprList(x.Lbrace, x.Elts, 1, commaSep|commaTerm, multiLine, x.Rbrace)
+		p.exprList(x.Lbrace, x.Elts, 1, commaTerm, x.Rbrace)
 		// do not insert extra line breaks because of comments before
 		// the closing '}' as it might break the code if there is no
 		// trailing ','
@@ -825,16 +805,16 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 	case *ast.Ellipsis:
 		p.print(token.ELLIPSIS)
 		if x.Elt != nil {
-			p.expr(x.Elt, multiLine)
+			p.expr(x.Elt)
 		}
 
 	case *ast.ArrayType:
 		p.print(token.LBRACK)
 		if x.Len != nil {
-			p.expr(x.Len, multiLine)
+			p.expr(x.Len)
 		}
 		p.print(token.RBRACK)
-		p.expr(x.Elt, multiLine)
+		p.expr(x.Elt)
 
 	case *ast.StructType:
 		p.print(token.STRUCT)
@@ -842,7 +822,7 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 
 	case *ast.FuncType:
 		p.print(token.FUNC)
-		p.signature(x.Params, x.Results, multiLine)
+		p.signature(x.Params, x.Results)
 
 	case *ast.InterfaceType:
 		p.print(token.INTERFACE)
@@ -850,9 +830,9 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 
 	case *ast.MapType:
 		p.print(token.MAP, token.LBRACK)
-		p.expr(x.Key, multiLine)
+		p.expr(x.Key)
 		p.print(token.RBRACK)
-		p.expr(x.Value, multiLine)
+		p.expr(x.Value)
 
 	case *ast.ChanType:
 		switch x.Dir {
@@ -864,7 +844,7 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 			p.print(token.CHAN, token.ARROW)
 		}
 		p.print(blank)
-		p.expr(x.Value, multiLine)
+		p.expr(x.Value)
 
 	default:
 		panic("unreachable")
@@ -873,14 +853,13 @@ func (p *printer) expr1(expr ast.Expr, prec1, depth int, multiLine *bool) {
 	return
 }
 
-func (p *printer) expr0(x ast.Expr, depth int, multiLine *bool) {
-	p.expr1(x, token.LowestPrec, depth, multiLine)
+func (p *printer) expr0(x ast.Expr, depth int) {
+	p.expr1(x, token.LowestPrec, depth)
 }
 
-// Sets multiLine to true if the expression spans multiple lines.
-func (p *printer) expr(x ast.Expr, multiLine *bool) {
+func (p *printer) expr(x ast.Expr) {
 	const depth = 1
-	p.expr1(x, token.LowestPrec, depth, multiLine)
+	p.expr1(x, token.LowestPrec, depth)
 }
 
 // ----------------------------------------------------------------------------
@@ -894,13 +873,13 @@ func (p *printer) stmtList(list []ast.Stmt, _indent int, nextIsRBrace bool) {
 	if _indent > 0 {
 		p.print(indent)
 	}
-	var multiLine bool
+	multiLine := false
 	for i, s := range list {
 		// _indent == 0 only for lists of switch/select case clauses;
 		// in those cases each clause is a new section
 		p.linebreak(p.lineFor(s.Pos()), 1, ignore, i == 0 || _indent == 0 || multiLine)
-		multiLine = false
-		p.stmt(s, nextIsRBrace && i == len(list)-1, &multiLine)
+		p.stmt(s, nextIsRBrace && i == len(list)-1)
+		multiLine = p.isMultiLine(s)
 	}
 	if _indent > 0 {
 		p.print(unindent)
@@ -957,25 +936,25 @@ func (p *printer) controlClause(isForStmt bool, init ast.Stmt, expr ast.Expr, po
 	if init == nil && post == nil {
 		// no semicolons required
 		if expr != nil {
-			p.expr(stripParens(expr), ignoreMultiLine)
+			p.expr(stripParens(expr))
 			needsBlank = true
 		}
 	} else {
 		// all semicolons required
 		// (they are not separators, print them explicitly)
 		if init != nil {
-			p.stmt(init, false, ignoreMultiLine)
+			p.stmt(init, false)
 		}
 		p.print(token.SEMICOLON, blank)
 		if expr != nil {
-			p.expr(stripParens(expr), ignoreMultiLine)
+			p.expr(stripParens(expr))
 			needsBlank = true
 		}
 		if isForStmt {
 			p.print(token.SEMICOLON, blank)
 			needsBlank = false
 			if post != nil {
-				p.stmt(post, false, ignoreMultiLine)
+				p.stmt(post, false)
 				needsBlank = true
 			}
 		}
@@ -985,8 +964,7 @@ func (p *printer) controlClause(isForStmt bool, init ast.Stmt, expr ast.Expr, po
 	}
 }
 
-// Sets multiLine to true if the statements spans multiple lines.
-func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool, multiLine *bool) {
+func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool) {
 	p.print(stmt.Pos())
 
 	switch s := stmt.(type) {
@@ -994,7 +972,7 @@ func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool, multiLine *bool) {
 		p.print("BadStmt")
 
 	case *ast.DeclStmt:
-		p.decl(s.Decl, multiLine)
+		p.decl(s.Decl)
 
 	case *ast.EmptyStmt:
 		// nothing to do
@@ -1004,7 +982,7 @@ func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool, multiLine *bool) {
 		// is applied before the line break if there is no comment
 		// between (see writeWhitespace)
 		p.print(unindent)
-		p.expr(s.Label, multiLine)
+		p.expr(s.Label)
 		p.print(s.Colon, token.COLON, indent)
 		if e, isEmpty := s.Stmt.(*ast.EmptyStmt); isEmpty {
 			if !nextIsRBrace {
@@ -1014,21 +992,21 @@ func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool, multiLine *bool) {
 		} else {
 			p.linebreak(p.lineFor(s.Stmt.Pos()), 1, ignore, true)
 		}
-		p.stmt(s.Stmt, nextIsRBrace, multiLine)
+		p.stmt(s.Stmt, nextIsRBrace)
 
 	case *ast.ExprStmt:
 		const depth = 1
-		p.expr0(s.X, depth, multiLine)
+		p.expr0(s.X, depth)
 
 	case *ast.SendStmt:
 		const depth = 1
-		p.expr0(s.Chan, depth, multiLine)
+		p.expr0(s.Chan, depth)
 		p.print(blank, s.Arrow, token.ARROW, blank)
-		p.expr0(s.Value, depth, multiLine)
+		p.expr0(s.Value, depth)
 
 	case *ast.IncDecStmt:
 		const depth = 1
-		p.expr0(s.X, depth+1, multiLine)
+		p.expr0(s.X, depth+1)
 		p.print(s.TokPos, s.Tok)
 
 	case *ast.AssignStmt:
@@ -1036,56 +1014,55 @@ func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool, multiLine *bool) {
 		if len(s.Lhs) > 1 && len(s.Rhs) > 1 {
 			depth++
 		}
-		p.exprList(s.Pos(), s.Lhs, depth, commaSep, multiLine, s.TokPos)
-		p.print(blank, s.TokPos, s.Tok)
-		p.exprList(s.TokPos, s.Rhs, depth, blankStart|commaSep, multiLine, token.NoPos)
+		p.exprList(s.Pos(), s.Lhs, depth, 0, s.TokPos)
+		p.print(blank, s.TokPos, s.Tok, blank)
+		p.exprList(s.TokPos, s.Rhs, depth, 0, token.NoPos)
 
 	case *ast.GoStmt:
 		p.print(token.GO, blank)
-		p.expr(s.Call, multiLine)
+		p.expr(s.Call)
 
 	case *ast.DeferStmt:
 		p.print(token.DEFER, blank)
-		p.expr(s.Call, multiLine)
+		p.expr(s.Call)
 
 	case *ast.ReturnStmt:
 		p.print(token.RETURN)
 		if s.Results != nil {
-			p.exprList(s.Pos(), s.Results, 1, blankStart|commaSep, multiLine, token.NoPos)
+			p.print(blank)
+			p.exprList(s.Pos(), s.Results, 1, 0, token.NoPos)
 		}
 
 	case *ast.BranchStmt:
 		p.print(s.Tok)
 		if s.Label != nil {
 			p.print(blank)
-			p.expr(s.Label, multiLine)
+			p.expr(s.Label)
 		}
 
 	case *ast.BlockStmt:
 		p.block(s, 1)
-		*multiLine = true
 
 	case *ast.IfStmt:
 		p.print(token.IF)
 		p.controlClause(false, s.Init, s.Cond, nil)
 		p.block(s.Body, 1)
-		*multiLine = true
 		if s.Else != nil {
 			p.print(blank, token.ELSE, blank)
 			switch s.Else.(type) {
 			case *ast.BlockStmt, *ast.IfStmt:
-				p.stmt(s.Else, nextIsRBrace, ignoreMultiLine)
+				p.stmt(s.Else, nextIsRBrace)
 			default:
 				p.print(token.LBRACE, indent, formfeed)
-				p.stmt(s.Else, true, ignoreMultiLine)
+				p.stmt(s.Else, true)
 				p.print(unindent, formfeed, token.RBRACE)
 			}
 		}
 
 	case *ast.CaseClause:
 		if s.List != nil {
-			p.print(token.CASE)
-			p.exprList(s.Pos(), s.List, 1, blankStart|commaSep, multiLine, s.Colon)
+			p.print(token.CASE, blank)
+			p.exprList(s.Pos(), s.List, 1, 0, s.Colon)
 		} else {
 			p.print(token.DEFAULT)
 		}
@@ -1096,25 +1073,23 @@ func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool, multiLine *bool) {
 		p.print(token.SWITCH)
 		p.controlClause(false, s.Init, s.Tag, nil)
 		p.block(s.Body, 0)
-		*multiLine = true
 
 	case *ast.TypeSwitchStmt:
 		p.print(token.SWITCH)
 		if s.Init != nil {
 			p.print(blank)
-			p.stmt(s.Init, false, ignoreMultiLine)
+			p.stmt(s.Init, false)
 			p.print(token.SEMICOLON)
 		}
 		p.print(blank)
-		p.stmt(s.Assign, false, ignoreMultiLine)
+		p.stmt(s.Assign, false)
 		p.print(blank)
 		p.block(s.Body, 0)
-		*multiLine = true
 
 	case *ast.CommClause:
 		if s.Comm != nil {
 			p.print(token.CASE, blank)
-			p.stmt(s.Comm, false, ignoreMultiLine)
+			p.stmt(s.Comm, false)
 		} else {
 			p.print(token.DEFAULT)
 		}
@@ -1129,29 +1104,26 @@ func (p *printer) stmt(stmt ast.Stmt, nextIsRBrace bool, multiLine *bool) {
 			p.print(body.Lbrace, token.LBRACE, body.Rbrace, token.RBRACE)
 		} else {
 			p.block(body, 0)
-			*multiLine = true
 		}
 
 	case *ast.ForStmt:
 		p.print(token.FOR)
 		p.controlClause(true, s.Init, s.Cond, s.Post)
 		p.block(s.Body, 1)
-		*multiLine = true
 
 	case *ast.RangeStmt:
 		p.print(token.FOR, blank)
-		p.expr(s.Key, multiLine)
+		p.expr(s.Key)
 		if s.Value != nil {
 			// use position of value following the comma as
 			// comma position for correct comment placement
 			p.print(s.Value.Pos(), token.COMMA, blank)
-			p.expr(s.Value, multiLine)
+			p.expr(s.Value)
 		}
 		p.print(blank, s.TokPos, s.Tok, blank, token.RANGE, blank)
-		p.expr(stripParens(s.X), multiLine)
+		p.expr(stripParens(s.X))
 		p.print(blank)
 		p.block(s.Body, 1)
-		*multiLine = true
 
 	default:
 		panic("unreachable")
@@ -1228,20 +1200,20 @@ func keepTypeColumn(specs []ast.Spec) []bool {
 	return m
 }
 
-func (p *printer) valueSpec(s *ast.ValueSpec, keepType, doIndent bool, multiLine *bool) {
+func (p *printer) valueSpec(s *ast.ValueSpec, keepType, doIndent bool) {
 	p.setComment(s.Doc)
-	p.identList(s.Names, doIndent, multiLine) // always present
+	p.identList(s.Names, doIndent) // always present
 	extraTabs := 3
 	if s.Type != nil || keepType {
 		p.print(vtab)
 		extraTabs--
 	}
 	if s.Type != nil {
-		p.expr(s.Type, multiLine)
+		p.expr(s.Type)
 	}
 	if s.Values != nil {
-		p.print(vtab, token.ASSIGN)
-		p.exprList(token.NoPos, s.Values, 1, blankStart|commaSep, multiLine, token.NoPos)
+		p.print(vtab, token.ASSIGN, blank)
+		p.exprList(token.NoPos, s.Values, 1, 0, token.NoPos)
 		extraTabs--
 	}
 	if s.Comment != nil {
@@ -1255,17 +1227,16 @@ func (p *printer) valueSpec(s *ast.ValueSpec, keepType, doIndent bool, multiLine
 // The parameter n is the number of specs in the group. If doIndent is set,
 // multi-line identifier lists in the spec are indented when the first
 // linebreak is encountered.
-// Sets multiLine to true if the spec spans multiple lines.
 //
-func (p *printer) spec(spec ast.Spec, n int, doIndent bool, multiLine *bool) {
+func (p *printer) spec(spec ast.Spec, n int, doIndent bool) {
 	switch s := spec.(type) {
 	case *ast.ImportSpec:
 		p.setComment(s.Doc)
 		if s.Name != nil {
-			p.expr(s.Name, multiLine)
+			p.expr(s.Name)
 			p.print(blank)
 		}
-		p.expr(s.Path, multiLine)
+		p.expr(s.Path)
 		p.setComment(s.Comment)
 		p.print(s.EndPos)
 
@@ -1274,26 +1245,26 @@ func (p *printer) spec(spec ast.Spec, n int, doIndent bool, multiLine *bool) {
 			p.internalError("expected n = 1; got", n)
 		}
 		p.setComment(s.Doc)
-		p.identList(s.Names, doIndent, multiLine) // always present
+		p.identList(s.Names, doIndent) // always present
 		if s.Type != nil {
 			p.print(blank)
-			p.expr(s.Type, multiLine)
+			p.expr(s.Type)
 		}
 		if s.Values != nil {
-			p.print(blank, token.ASSIGN)
-			p.exprList(token.NoPos, s.Values, 1, blankStart|commaSep, multiLine, token.NoPos)
+			p.print(blank, token.ASSIGN, blank)
+			p.exprList(token.NoPos, s.Values, 1, 0, token.NoPos)
 		}
 		p.setComment(s.Comment)
 
 	case *ast.TypeSpec:
 		p.setComment(s.Doc)
-		p.expr(s.Name, multiLine)
+		p.expr(s.Name)
 		if n == 1 {
 			p.print(blank)
 		} else {
 			p.print(vtab)
 		}
-		p.expr(s.Type, multiLine)
+		p.expr(s.Type)
 		p.setComment(s.Comment)
 
 	default:
@@ -1301,8 +1272,7 @@ func (p *printer) spec(spec ast.Spec, n int, doIndent bool, multiLine *bool) {
 	}
 }
 
-// Sets multiLine to true if the declaration spans multiple lines.
-func (p *printer) genDecl(d *ast.GenDecl, multiLine *bool) {
+func (p *printer) genDecl(d *ast.GenDecl) {
 	p.setComment(d.Doc)
 	p.print(d.Pos(), d.Tok, blank)
 
@@ -1315,32 +1285,31 @@ func (p *printer) genDecl(d *ast.GenDecl, multiLine *bool) {
 				// two or more grouped const/var declarations:
 				// determine if the type column must be kept
 				keepType := keepTypeColumn(d.Specs)
-				var ml bool
+				newSection := false
 				for i, s := range d.Specs {
 					if i > 0 {
-						p.linebreak(p.lineFor(s.Pos()), 1, ignore, ml)
+						p.linebreak(p.lineFor(s.Pos()), 1, ignore, newSection)
 					}
-					ml = false
-					p.valueSpec(s.(*ast.ValueSpec), keepType[i], false, &ml)
+					p.valueSpec(s.(*ast.ValueSpec), keepType[i], false)
+					newSection = p.isMultiLine(s)
 				}
 			} else {
-				var ml bool
+				newSection := false
 				for i, s := range d.Specs {
 					if i > 0 {
-						p.linebreak(p.lineFor(s.Pos()), 1, ignore, ml)
+						p.linebreak(p.lineFor(s.Pos()), 1, ignore, newSection)
 					}
-					ml = false
-					p.spec(s, n, false, &ml)
+					p.spec(s, n, false)
+					newSection = p.isMultiLine(s)
 				}
 			}
 			p.print(unindent, formfeed)
-			*multiLine = true
 		}
 		p.print(d.Rparen, token.RPAREN)
 
 	} else {
 		// single declaration
-		p.spec(d.Specs[0], 1, true, multiLine)
+		p.spec(d.Specs[0], 1, true)
 	}
 }
 
@@ -1404,8 +1373,7 @@ func (p *printer) isOneLineFunc(b *ast.BlockStmt, headerSize int) bool {
 	return headerSize+bodySize <= maxSize
 }
 
-// Sets multiLine to true if the function body spans multiple lines.
-func (p *printer) funcBody(b *ast.BlockStmt, headerSize int, isLit bool, multiLine *bool) {
+func (p *printer) funcBody(b *ast.BlockStmt, headerSize int, isLit bool) {
 	if b == nil {
 		return
 	}
@@ -1422,7 +1390,7 @@ func (p *printer) funcBody(b *ast.BlockStmt, headerSize int, isLit bool, multiLi
 				if i > 0 {
 					p.print(token.SEMICOLON, blank)
 				}
-				p.stmt(s, i == len(b.List)-1, ignoreMultiLine)
+				p.stmt(s, i == len(b.List)-1)
 			}
 			p.print(blank)
 		}
@@ -1432,7 +1400,6 @@ func (p *printer) funcBody(b *ast.BlockStmt, headerSize int, isLit bool, multiLi
 
 	p.print(blank)
 	p.block(b, 1)
-	*multiLine = true
 }
 
 // distance returns the column difference between from and to if both
@@ -1446,28 +1413,26 @@ func (p *printer) distance(from0 token.Pos, to token.Position) int {
 	return infinity
 }
 
-// Sets multiLine to true if the declaration spans multiple lines.
-func (p *printer) funcDecl(d *ast.FuncDecl, multiLine *bool) {
+func (p *printer) funcDecl(d *ast.FuncDecl) {
 	p.setComment(d.Doc)
 	p.print(d.Pos(), token.FUNC, blank)
 	if d.Recv != nil {
-		p.parameters(d.Recv, multiLine) // method: print receiver
+		p.parameters(d.Recv) // method: print receiver
 		p.print(blank)
 	}
-	p.expr(d.Name, multiLine)
-	p.signature(d.Type.Params, d.Type.Results, multiLine)
-	p.funcBody(d.Body, p.distance(d.Pos(), p.pos), false, multiLine)
+	p.expr(d.Name)
+	p.signature(d.Type.Params, d.Type.Results)
+	p.funcBody(d.Body, p.distance(d.Pos(), p.pos), false)
 }
 
-// Sets multiLine to true if the declaration spans multiple lines.
-func (p *printer) decl(decl ast.Decl, multiLine *bool) {
+func (p *printer) decl(decl ast.Decl) {
 	switch d := decl.(type) {
 	case *ast.BadDecl:
 		p.print(d.Pos(), "BadDecl")
 	case *ast.GenDecl:
-		p.genDecl(d, multiLine)
+		p.genDecl(d)
 	case *ast.FuncDecl:
-		p.funcDecl(d, multiLine)
+		p.funcDecl(d)
 	default:
 		panic("unreachable")
 	}
@@ -1490,7 +1455,7 @@ func declToken(decl ast.Decl) (tok token.Token) {
 func (p *printer) file(src *ast.File) {
 	p.setComment(src.Doc)
 	p.print(src.Pos(), token.PACKAGE, blank)
-	p.expr(src.Name, ignoreMultiLine)
+	p.expr(src.Name)
 
 	if len(src.Decls) > 0 {
 		tok := token.ILLEGAL
@@ -1509,7 +1474,7 @@ func (p *printer) file(src *ast.File) {
 				min = 2
 			}
 			p.linebreak(p.lineFor(d.Pos()), min, ignore, false)
-			p.decl(d, ignoreMultiLine)
+			p.decl(d)
 		}
 	}
 
diff --git a/libgo/go/go/printer/printer.go b/libgo/go/go/printer/printer.go
index 72f65a1d852..a027d32da89 100644
--- a/libgo/go/go/printer/printer.go
+++ b/libgo/go/go/printer/printer.go
@@ -34,9 +34,6 @@ const (
 	unindent = whiteSpace('<')
 )
 
-// Use ignoreMultiLine if the multiLine information is not important.
-var ignoreMultiLine = new(bool)
-
 // A pmode value represents the current printer mode.
 type pmode int
 
@@ -280,10 +277,9 @@ func (p *printer) writeString(pos token.Position, s string, isLit bool) {
 // it as is likely to help position the comment nicely.
 // pos is the comment position, next the position of the item
 // after all pending comments, prev is the previous comment in
-// a group of comments (or nil), and isKeyword indicates if the
-// next item is a keyword.
+// a group of comments (or nil), and tok is the next token.
 //
-func (p *printer) writeCommentPrefix(pos, next token.Position, prev, comment *ast.Comment, isKeyword bool) {
+func (p *printer) writeCommentPrefix(pos, next token.Position, prev, comment *ast.Comment, tok token.Token) {
 	if len(p.output) == 0 {
 		// the comment is the first item to be printed - don't write any whitespace
 		return
@@ -338,38 +334,41 @@ func (p *printer) writeCommentPrefix(pos, next token.Position, prev, comment *as
 		// comment on a different line:
 		// separate with at least one line break
 		droppedLinebreak := false
-		if prev == nil {
-			// first comment of a comment group
-			j := 0
-			for i, ch := range p.wsbuf {
-				switch ch {
-				case blank, vtab:
-					// ignore any horizontal whitespace before line breaks
-					p.wsbuf[i] = ignore
+		j := 0
+		for i, ch := range p.wsbuf {
+			switch ch {
+			case blank, vtab:
+				// ignore any horizontal whitespace before line breaks
+				p.wsbuf[i] = ignore
+				continue
+			case indent:
+				// apply pending indentation
+				continue
+			case unindent:
+				// if this is not the last unindent, apply it
+				// as it is (likely) belonging to the last
+				// construct (e.g., a multi-line expression list)
+				// and is not part of closing a block
+				if i+1 < len(p.wsbuf) && p.wsbuf[i+1] == unindent {
 					continue
-				case indent:
-					// apply pending indentation
+				}
+				// if the next token is not a closing }, apply the unindent
+				// if it appears that the comment is aligned with the
+				// token; otherwise assume the unindent is part of a
+				// closing block and stop (this scenario appears with
+				// comments before a case label where the comments
+				// apply to the next case instead of the current one)
+				if tok != token.RBRACE && pos.Column == next.Column {
 					continue
-				case unindent:
-					// if the next token is a keyword, apply the outdent
-					// if it appears that the comment is aligned with the
-					// keyword; otherwise assume the outdent is part of a
-					// closing block and stop (this scenario appears with
-					// comments before a case label where the comments
-					// apply to the next case instead of the current one)
-					if isKeyword && pos.Column == next.Column {
-						continue
-					}
-				case newline, formfeed:
-					// TODO(gri): may want to keep formfeed info in some cases
-					p.wsbuf[i] = ignore
-					droppedLinebreak = true
 				}
-				j = i
-				break
+			case newline, formfeed:
+				p.wsbuf[i] = ignore
+				droppedLinebreak = prev == nil // record only if first comment of a group
 			}
-			p.writeWhitespace(j)
+			j = i
+			break
 		}
+		p.writeWhitespace(j)
 
 		// determine number of linebreaks before the comment
 		n := 0
@@ -678,7 +677,7 @@ func (p *printer) intersperseComments(next token.Position, tok token.Token) (wro
 	var last *ast.Comment
 	for p.commentBefore(next) {
 		for _, c := range p.comment.List {
-			p.writeCommentPrefix(p.posFor(c.Pos()), next, last, c, tok.IsKeyword())
+			p.writeCommentPrefix(p.posFor(c.Pos()), next, last, c, tok)
 			p.writeComment(c)
 			last = c
 		}
@@ -1011,18 +1010,18 @@ func (p *printer) printNode(node interface{}) error {
 	// format node
 	switch n := node.(type) {
 	case ast.Expr:
-		p.expr(n, ignoreMultiLine)
+		p.expr(n)
 	case ast.Stmt:
 		// A labeled statement will un-indent to position the
 		// label. Set indent to 1 so we don't get indent "underflow".
 		if _, labeledStmt := n.(*ast.LabeledStmt); labeledStmt {
 			p.indent = 1
 		}
-		p.stmt(n, false, ignoreMultiLine)
+		p.stmt(n, false)
 	case ast.Decl:
-		p.decl(n, ignoreMultiLine)
+		p.decl(n)
 	case ast.Spec:
-		p.spec(n, 1, false, ignoreMultiLine)
+		p.spec(n, 1, false)
 	case *ast.File:
 		p.file(n)
 	default:
diff --git a/libgo/go/go/printer/printer_test.go b/libgo/go/go/printer/printer_test.go
index 2d4f61356c1..497d671f240 100644
--- a/libgo/go/go/printer/printer_test.go
+++ b/libgo/go/go/printer/printer_test.go
@@ -154,15 +154,12 @@ var data = []entry{
 }
 
 func TestFiles(t *testing.T) {
-	for i, e := range data {
+	for _, e := range data {
 		source := filepath.Join(dataDir, e.source)
 		golden := filepath.Join(dataDir, e.golden)
 		check(t, source, golden, e.mode)
 		// TODO(gri) check that golden is idempotent
 		//check(t, golden, golden, e.mode)
-		if testing.Short() && i >= 3 {
-			break
-		}
 	}
 }
 
diff --git a/libgo/go/go/printer/testdata/comments.golden b/libgo/go/go/printer/testdata/comments.golden
index 4c6f1ab8274..d9aa2d82f7d 100644
--- a/libgo/go/go/printer/testdata/comments.golden
+++ b/libgo/go/go/printer/testdata/comments.golden
@@ -168,6 +168,91 @@ func typeswitch(x interface{}) {
 	// this comment should not be indented
 }
 
+//
+// Indentation of comments after possibly indented multi-line constructs
+// (test cases for issue 3147).
+//
+
+func _() {
+	s := 1 +
+		2
+	// should be indented like s
+}
+
+func _() {
+	s := 1 +
+		2	// comment
+	// should be indented like s
+}
+
+func _() {
+	s := 1 +
+		2	// comment
+	// should be indented like s
+	_ = 0
+}
+
+func _() {
+	s := 1 +
+		2
+	// should be indented like s
+	_ = 0
+}
+
+func _() {
+	s := 1 +
+		2
+
+	// should be indented like s
+}
+
+func _() {
+	s := 1 +
+		2	// comment
+
+	// should be indented like s
+}
+
+func _() {
+	s := 1 +
+		2	// comment
+
+	// should be indented like s
+	_ = 0
+}
+
+func _() {
+	s := 1 +
+		2
+
+	// should be indented like s
+	_ = 0
+}
+
+// Test case from issue 3147.
+func f() {
+	templateText := "a" +	// A
+		"b" +	// B
+		"c"	// C
+
+	// should be aligned with f()
+	f()
+}
+
+// Modified test case from issue 3147.
+func f() {
+	templateText := "a" +	// A
+		"b" +	// B
+		"c"	// C
+
+		// may not be aligned with f() (source is not aligned)
+	f()
+}
+
+//
+// Test cases for alignment of lines in general comments.
+//
+
 func _() {
 	/* freestanding comment
 	   aligned		line
diff --git a/libgo/go/go/printer/testdata/comments.input b/libgo/go/go/printer/testdata/comments.input
index c0f8cca3a92..6084b3fe450 100644
--- a/libgo/go/go/printer/testdata/comments.input
+++ b/libgo/go/go/printer/testdata/comments.input
@@ -171,6 +171,91 @@ func typeswitch(x interface{}) {
 	// this comment should not be indented
 }
 
+//
+// Indentation of comments after possibly indented multi-line constructs
+// (test cases for issue 3147).
+//
+
+func _() {
+	s := 1 +
+		2
+// should be indented like s
+}
+
+func _() {
+	s := 1 +
+		2 // comment
+		// should be indented like s
+}
+
+func _() {
+	s := 1 +
+		2 // comment
+	// should be indented like s
+	_ = 0
+}
+
+func _() {
+	s := 1 +
+		2
+	// should be indented like s
+	_ = 0
+}
+
+func _() {
+	s := 1 +
+		2
+
+// should be indented like s
+}
+
+func _() {
+	s := 1 +
+		2 // comment
+
+		// should be indented like s
+}
+
+func _() {
+	s := 1 +
+		2 // comment
+
+	// should be indented like s
+	_ = 0
+}
+
+func _() {
+	s := 1 +
+		2
+
+	// should be indented like s
+	_ = 0
+}
+
+// Test case from issue 3147.
+func f() {
+	templateText := "a" + // A
+		"b" + // B
+		"c" // C
+
+	// should be aligned with f()
+	f()
+}
+
+// Modified test case from issue 3147.
+func f() {
+	templateText := "a" + // A
+		"b" + // B
+		"c" // C
+
+		// may not be aligned with f() (source is not aligned)
+	f()
+}
+
+//
+// Test cases for alignment of lines in general comments.
+//
+
 func _() {
 	/* freestanding comment
 	   aligned		line
diff --git a/libgo/go/go/printer/testdata/declarations.golden b/libgo/go/go/printer/testdata/declarations.golden
index 928b8ce0a9f..7ed7cb61ae5 100644
--- a/libgo/go/go/printer/testdata/declarations.golden
+++ b/libgo/go/go/printer/testdata/declarations.golden
@@ -83,13 +83,13 @@ import (
 // more import examples
 import (
 	"xxx"
-	"much longer name"	// comment
-	"short name"		// comment
+	"much_longer_name"	// comment
+	"short_name"		// comment
 )
 
 import (
 	_ "xxx"
-	"much longer name"	// comment
+	"much_longer_name"	// comment
 )
 
 import (
@@ -500,7 +500,7 @@ type _ struct {
 
 type _ struct {
 	a, b,
-	c, d	int	// this line should be indented
+	c, d		int	// this line should be indented
 	u, v, w, x	float	// this line should be indented
 	p, q,
 	r, s	float	// this line should be indented
@@ -562,7 +562,7 @@ var a2, b2,
 
 var (
 	a3, b3,
-	c3, d3	int	// this line should be indented
+	c3, d3		int	// this line should be indented
 	a4, b4, c4	int	// this line should be indented
 )
 
diff --git a/libgo/go/go/printer/testdata/declarations.input b/libgo/go/go/printer/testdata/declarations.input
index 68f90308a36..df8c2b167e1 100644
--- a/libgo/go/go/printer/testdata/declarations.input
+++ b/libgo/go/go/printer/testdata/declarations.input
@@ -84,13 +84,13 @@ import (
 // more import examples
 import (
 	"xxx"
-	"much longer name" // comment
-	"short name" // comment
+	"much_longer_name" // comment
+	"short_name" // comment
 )
 
 import (
 	_ "xxx"
-	"much longer name" // comment
+	"much_longer_name" // comment
 )
 
 import (
diff --git a/libgo/go/go/printer/testdata/expressions.golden b/libgo/go/go/printer/testdata/expressions.golden
index 95fdd95ffbb..45fa4d97a4a 100644
--- a/libgo/go/go/printer/testdata/expressions.golden
+++ b/libgo/go/go/printer/testdata/expressions.golden
@@ -625,3 +625,25 @@ func f() {
 		log.Fatal(err)
 	}
 }
+
+// Handle multi-line argument lists ending in ... correctly.
+// Was issue 3130.
+func _() {
+	_ = append(s, a...)
+	_ = append(
+		s, a...)
+	_ = append(s,
+		a...)
+	_ = append(
+		s,
+		a...)
+	_ = append(s, a...,
+	)
+	_ = append(s,
+		a...,
+	)
+	_ = append(
+		s,
+		a...,
+	)
+}
diff --git a/libgo/go/go/printer/testdata/expressions.input b/libgo/go/go/printer/testdata/expressions.input
index d1131498352..f545c66057c 100644
--- a/libgo/go/go/printer/testdata/expressions.input
+++ b/libgo/go/go/printer/testdata/expressions.input
@@ -654,3 +654,25 @@ func f() {
 	    log.Fatal(err)
 	}
 }
+
+// Handle multi-line argument lists ending in ... correctly.
+// Was issue 3130.
+func _() {
+	_ = append(s, a...)
+	_ = append(
+		s, a...)
+	_ = append(s,
+		a...)
+	_ = append(
+		s,
+		a...)
+	_ = append(s, a...,
+	)
+	_ = append(s,
+		a...,
+	)
+	_ = append(
+		s,
+		a...,
+	)
+}
diff --git a/libgo/go/go/printer/testdata/expressions.raw b/libgo/go/go/printer/testdata/expressions.raw
index 3442ba9b950..87a4b00836d 100644
--- a/libgo/go/go/printer/testdata/expressions.raw
+++ b/libgo/go/go/printer/testdata/expressions.raw
@@ -625,3 +625,25 @@ func f() {
 		log.Fatal(err)
 	}
 }
+
+// Handle multi-line argument lists ending in ... correctly.
+// Was issue 3130.
+func _() {
+	_ = append(s, a...)
+	_ = append(
+		s, a...)
+	_ = append(s,
+		a...)
+	_ = append(
+		s,
+		a...)
+	_ = append(s, a...,
+	)
+	_ = append(s,
+		a...,
+	)
+	_ = append(
+		s,
+		a...,
+	)
+}
diff --git a/libgo/go/go/printer/testdata/parser.go b/libgo/go/go/printer/testdata/parser.go
index c85297f5831..dba8bbd4351 100644
--- a/libgo/go/go/printer/testdata/parser.go
+++ b/libgo/go/go/printer/testdata/parser.go
@@ -52,7 +52,7 @@ type parser struct {
 	// Non-syntactic parser control
 	exprLev int // < 0: in control clause, >= 0: in expression
 
-	// Ordinary identifer scopes
+	// Ordinary identifier scopes
 	pkgScope   *ast.Scope        // pkgScope.Outer == nil
 	topScope   *ast.Scope        // top-most scope; may be pkgScope
 	unresolved []*ast.Ident      // unresolved identifiers
diff --git a/libgo/go/go/printer/testdata/statements.golden b/libgo/go/go/printer/testdata/statements.golden
index 90e1743557d..ffca21edba9 100644
--- a/libgo/go/go/printer/testdata/statements.golden
+++ b/libgo/go/go/printer/testdata/statements.golden
@@ -8,6 +8,82 @@ var expr bool
 
 func use(x interface{})	{}
 
+// Formatting of multi-line return statements.
+func _f() {
+	return
+	return x, y, z
+	return T{}
+	return T{1, 2, 3},
+		x, y, z
+	return T{1, 2, 3},
+		x, y,
+		z
+	return T{1,
+		2,
+		3}
+	return T{1,
+		2,
+		3,
+	}
+	return T{
+		1,
+		2,
+		3}
+	return T{
+		1,
+		2,
+		3,
+	}
+	return T{
+		1,
+		T{1, 2, 3},
+		3,
+	}
+	return T{
+		1,
+		T{1,
+			2, 3},
+		3,
+	}
+	return T{
+		1,
+		T{1,
+			2,
+			3},
+		3,
+	}
+	return T{
+		1,
+		2,
+	},
+		nil
+	return T{
+		1,
+		2,
+	},
+		T{
+			x:	3,
+			y:	4,
+		},
+		nil
+	return x + y +
+		z
+	return func() {}
+	return func() {
+		_ = 0
+	}, T{
+		1, 2,
+	}
+	return func() {
+		_ = 0
+	}
+	return func() T {
+		return T{
+			1, 2,
+		}
+	}
+}
+
 // Formatting of if-statement headers.
 func _() {
 	if true {
diff --git a/libgo/go/go/printer/testdata/statements.input b/libgo/go/go/printer/testdata/statements.input
index 86a753c5ad9..99945e9551a 100644
--- a/libgo/go/go/printer/testdata/statements.input
+++ b/libgo/go/go/printer/testdata/statements.input
@@ -8,6 +8,82 @@ var expr bool
 
 func use(x interface{}) {}
 
+// Formatting of multi-line return statements.
+func _f() {
+	return
+	return x, y, z
+	return T{}
+	return T{1, 2, 3},
+		x, y, z
+	return T{1, 2, 3},
+		x, y,
+		z
+	return T{1,
+		2,
+		3}
+	return T{1,
+		2,
+		3,
+	}
+	return T{
+		1,
+		2,
+		3}
+	return T{
+		1,
+		2,
+		3,
+	}
+	return T{
+		1,
+		T{1, 2, 3},
+		3,
+	}
+	return T{
+		1,
+		T{1,
+			2, 3},
+		3,
+	}
+	return T{
+		1,
+		T{1,
+			2,
+			3},
+		3,
+	}
+	return T{
+			1,
+			2,
+		},
+		nil
+	return T{
+			1,
+			2,
+		},
+		T{
+			x: 3,
+			y: 4,
+		},
+		nil
+	return x + y +
+		z
+	return func() {}
+	return func() {
+		_ = 0
+	}, T{
+		1, 2,
+	}
+	return func() {
+		_ = 0
+	}
+	return func() T {
+		return T {
+			1, 2,
+		}
+	}
+}
+
 // Formatting of if-statement headers.
 func _() {
 	if true {}
diff --git a/libgo/go/html/template/doc.go b/libgo/go/html/template/doc.go
index 7f60f3b9680..3699ea1a91c 100644
--- a/libgo/go/html/template/doc.go
+++ b/libgo/go/html/template/doc.go
@@ -19,7 +19,7 @@ to parse and execute HTML templates safely.
 
   tmpl, err := template.New("name").Parse(...)
   // Error checking elided
-  err = tmpl.Execute(out, "Foo", data)
+  err = tmpl.Execute(out, data)
 
 If successful, tmpl will now be injection-safe. Otherwise, err is an error
 defined in the docs for ErrorCode.
diff --git a/libgo/go/html/template/escape.go b/libgo/go/html/template/escape.go
index 02fa3eaad6b..a058e20d7b3 100644
--- a/libgo/go/html/template/escape.go
+++ b/libgo/go/html/template/escape.go
@@ -593,7 +593,7 @@ func (e *escaper) escapeText(c context, n *parse.TextNode) context {
 				}
 			}
 			for j := i; j < end; j++ {
-				if s[j] == '<' && !bytes.HasPrefix(s[j:], doctypeBytes) {
+				if s[j] == '<' && !bytes.HasPrefix(bytes.ToUpper(s[j:]), doctypeBytes) {
 					b.Write(s[written:j])
 					b.WriteString("&lt;")
 					written = j + 1
diff --git a/libgo/go/html/template/escape_test.go b/libgo/go/html/template/escape_test.go
index 70cada3f50b..2bbb1b1bc94 100644
--- a/libgo/go/html/template/escape_test.go
+++ b/libgo/go/html/template/escape_test.go
@@ -223,14 +223,14 @@ func TestEscape(t *testing.T) {
 			`<button onclick='alert(&quot;\x3cHello\x3e&quot;)'>`,
 		},
 		{
-			"badMarshaller",
+			"badMarshaler",
 			`<button onclick='alert(1/{{.B}}in numbers)'>`,
 			`<button onclick='alert(1/ /* json: error calling MarshalJSON for type *template.badMarshaler: invalid character &#39;f&#39; looking for beginning of object key string */null in numbers)'>`,
 		},
 		{
-			"jsMarshaller",
+			"jsMarshaler",
 			`<button onclick='alert({{.M}})'>`,
-			`<button onclick='alert({&#34;&lt;foo&gt;&#34;:&#34;O&#39;Reilly&#34;})'>`,
+			`<button onclick='alert({&#34;\u003cfoo\u003e&#34;:&#34;O&#39;Reilly&#34;})'>`,
 		},
 		{
 			"jsStrNotUnderEscaped",
@@ -432,6 +432,11 @@ func TestEscape(t *testing.T) {
 			"<!DOCTYPE html>Hello, World!",
 		},
 		{
+			"HTML doctype not case-insensitive",
+			"<!doCtYPE htMl>Hello, World!",
+			"<!doCtYPE htMl>Hello, World!",
+		},
+		{
 			"No doctype injection",
 			`<!{{"DOCTYPE"}}`,
 			"&lt;!DOCTYPE",
diff --git a/libgo/go/html/template/html.go b/libgo/go/html/template/html.go
index 7b77d6531ab..36c88e23e6e 100644
--- a/libgo/go/html/template/html.go
+++ b/libgo/go/html/template/html.go
@@ -134,7 +134,7 @@ var htmlNospaceNormReplacementTable = []string{
 	'`': "&#96;",
 }
 
-// htmlReplacer returns s with runes replaced acccording to replacementTable
+// htmlReplacer returns s with runes replaced according to replacementTable
 // and when badRunes is true, certain bad runes are allowed through unescaped.
 func htmlReplacer(s string, replacementTable []string, badRunes bool) string {
 	written, b := 0, new(bytes.Buffer)
diff --git a/libgo/go/io/io.go b/libgo/go/io/io.go
index bbfa6c2b2aa..7074834d613 100644
--- a/libgo/go/io/io.go
+++ b/libgo/go/io/io.go
@@ -6,6 +6,10 @@
 // Its primary job is to wrap existing implementations of such primitives,
 // such as those in package os, into shared public interfaces that
 // abstract the functionality, plus some other related primitives.
+//
+// Because these interfaces and primitives wrap lower-level operations with
+// various implementations, unless otherwise informed clients should not
+// assume they are safe for parallel execution.
 package io
 
 import (
@@ -156,6 +160,9 @@ type WriterTo interface {
 // If ReadAt is reading from an input source with a seek offset,
 // ReadAt should not affect nor be affected by the underlying
 // seek offset.
+//
+// Clients of ReadAt can execute parallel ReadAt calls on the
+// same input source.
 type ReaderAt interface {
 	ReadAt(p []byte, off int64) (n int, err error)
 }
diff --git a/libgo/go/io/pipe.go b/libgo/go/io/pipe.go
index cf05e0c1ad7..f3f0f175706 100644
--- a/libgo/go/io/pipe.go
+++ b/libgo/go/io/pipe.go
@@ -175,6 +175,10 @@ func (w *PipeWriter) CloseWithError(err error) error {
 // with code expecting an io.Writer.
 // Reads on one end are matched with writes on the other,
 // copying data directly between the two; there is no internal buffering.
+// It is safe to call Read and Write in parallel with each other or with
+// Close. Close will complete once pending I/O is done. Parallel calls to
+// Read, and parallel calls to Write, are also safe:
+// the individual calls will be gated sequentially.
 func Pipe() (*PipeReader, *PipeWriter) {
 	p := new(pipe)
 	p.rwait.L = &p.l
diff --git a/libgo/go/math/const.go b/libgo/go/math/const.go
index edb14f6fa43..f1247c383fd 100644
--- a/libgo/go/math/const.go
+++ b/libgo/go/math/const.go
@@ -27,11 +27,11 @@ const (
 // Max is the largest finite value representable by the type.
 // SmallestNonzero is the smallest positive, non-zero value representable by the type.
 const (
-	MaxFloat32             = 3.40282346638528859811704183484516925440e+38  /* 2**127 * (2**24 - 1) / 2**23 */
-	SmallestNonzeroFloat32 = 1.401298464324817070923729583289916131280e-45 /* 1 / 2**(127 - 1 + 23) */
+	MaxFloat32             = 3.40282346638528859811704183484516925440e+38  // 2**127 * (2**24 - 1) / 2**23
+	SmallestNonzeroFloat32 = 1.401298464324817070923729583289916131280e-45 // 1 / 2**(127 - 1 + 23)
 
-	MaxFloat64             = 1.797693134862315708145274237317043567981e+308 /* 2**1023 * (2**53 - 1) / 2**52 */
-	SmallestNonzeroFloat64 = 4.940656458412465441765687928682213723651e-324 /* 1 / 2**(1023 - 1 + 52) */
+	MaxFloat64             = 1.797693134862315708145274237317043567981e+308 // 2**1023 * (2**53 - 1) / 2**52
+	SmallestNonzeroFloat64 = 4.940656458412465441765687928682213723651e-324 // 1 / 2**(1023 - 1 + 52)
 )
 
 // Integer limit values.
diff --git a/libgo/go/net/dial.go b/libgo/go/net/dial.go
index 61b8911fcf9..10ca5faf707 100644
--- a/libgo/go/net/dial.go
+++ b/libgo/go/net/dial.go
@@ -69,7 +69,7 @@ func resolveNetAddr(op, net, addr string) (afnet string, a Addr, err error) {
 //
 // Known networks are "tcp", "tcp4" (IPv4-only), "tcp6" (IPv6-only),
 // "udp", "udp4" (IPv4-only), "udp6" (IPv6-only), "ip", "ip4"
-// (IPv4-only), "ip6" (IPv6-only), "unix", "unixgram" and "unixpacket".
+// (IPv4-only), "ip6" (IPv6-only), "unix" and "unixpacket".
 //
 // For TCP and UDP networks, addresses have the form host:port.
 // If host is a literal IPv6 address, it must be enclosed
diff --git a/libgo/go/net/dial_test.go b/libgo/go/net/dial_test.go
index e5a797e13bf..5f5aea146a6 100644
--- a/libgo/go/net/dial_test.go
+++ b/libgo/go/net/dial_test.go
@@ -5,6 +5,8 @@
 package net
 
 import (
+	"flag"
+	"regexp"
 	"runtime"
 	"testing"
 	"time"
@@ -128,3 +130,82 @@ func TestSelfConnect(t *testing.T) {
 		}
 	}
 }
+
+var runErrorTest = flag.Bool("run_error_test", false, "let TestDialError check for dns errors")
+
+type DialErrorTest struct {
+	Net     string
+	Raddr   string
+	Pattern string
+}
+
+var dialErrorTests = []DialErrorTest{
+	{
+		"datakit", "mh/astro/r70",
+		"dial datakit mh/astro/r70: unknown network datakit",
+	},
+	{
+		"tcp", "127.0.0.1:☺",
+		"dial tcp 127.0.0.1:☺: unknown port tcp/☺",
+	},
+	{
+		"tcp", "no-such-name.google.com.:80",
+		"dial tcp no-such-name.google.com.:80: lookup no-such-name.google.com.( on .*)?: no (.*)",
+	},
+	{
+		"tcp", "no-such-name.no-such-top-level-domain.:80",
+		"dial tcp no-such-name.no-such-top-level-domain.:80: lookup no-such-name.no-such-top-level-domain.( on .*)?: no (.*)",
+	},
+	{
+		"tcp", "no-such-name:80",
+		`dial tcp no-such-name:80: lookup no-such-name\.(.*\.)?( on .*)?: no (.*)`,
+	},
+	{
+		"tcp", "mh/astro/r70:http",
+		"dial tcp mh/astro/r70:http: lookup mh/astro/r70: invalid domain name",
+	},
+	{
+		"unix", "/etc/file-not-found",
+		"dial unix /etc/file-not-found: no such file or directory",
+	},
+	{
+		"unix", "/etc/",
+		"dial unix /etc/: (permission denied|socket operation on non-socket|connection refused)",
+	},
+	{
+		"unixpacket", "/etc/file-not-found",
+		"dial unixpacket /etc/file-not-found: no such file or directory",
+	},
+	{
+		"unixpacket", "/etc/",
+		"dial unixpacket /etc/: (permission denied|socket operation on non-socket|connection refused)",
+	},
+}
+
+var duplicateErrorPattern = `dial (.*) dial (.*)`
+
+func TestDialError(t *testing.T) {
+	if !*runErrorTest {
+		t.Logf("test disabled; use -run_error_test to enable")
+		return
+	}
+	for i, tt := range dialErrorTests {
+		c, err := Dial(tt.Net, tt.Raddr)
+		if c != nil {
+			c.Close()
+		}
+		if err == nil {
+			t.Errorf("#%d: nil error, want match for %#q", i, tt.Pattern)
+			continue
+		}
+		s := err.Error()
+		match, _ := regexp.MatchString(tt.Pattern, s)
+		if !match {
+			t.Errorf("#%d: %q, want match for %#q", i, s, tt.Pattern)
+		}
+		match, _ = regexp.MatchString(duplicateErrorPattern, s)
+		if match {
+			t.Errorf("#%d: %q, duplicate error return from Dial", i, s)
+		}
+	}
+}
diff --git a/libgo/go/net/dialgoogle_test.go b/libgo/go/net/dialgoogle_test.go
index 14356da4ce3..03c4499720f 100644
--- a/libgo/go/net/dialgoogle_test.go
+++ b/libgo/go/net/dialgoogle_test.go
@@ -42,9 +42,8 @@ func doDial(t *testing.T, network, addr string) {
 }
 
 func TestLookupCNAME(t *testing.T) {
-	if testing.Short() {
-		// Don't use external network.
-		t.Logf("skipping external network test during -short")
+	if testing.Short() || !*testExternal {
+		t.Logf("skipping test to avoid external network")
 		return
 	}
 	cname, err := LookupCNAME("www.google.com")
@@ -67,9 +66,8 @@ var googleaddrsipv4 = []string{
 }
 
 func TestDialGoogleIPv4(t *testing.T) {
-	if testing.Short() {
-		// Don't use external network.
-		t.Logf("skipping external network test during -short")
+	if testing.Short() || !*testExternal {
+		t.Logf("skipping test to avoid external network")
 		return
 	}
 
@@ -124,9 +122,8 @@ var googleaddrsipv6 = []string{
 }
 
 func TestDialGoogleIPv6(t *testing.T) {
-	if testing.Short() {
-		// Don't use external network.
-		t.Logf("skipping external network test during -short")
+	if testing.Short() || !*testExternal {
+		t.Logf("skipping test to avoid external network")
 		return
 	}
 	// Only run tcp6 if the kernel will take it.
diff --git a/libgo/go/net/http/cgi/child.go b/libgo/go/net/http/cgi/child.go
index e6c3ef911ab..1ba7bec5fc5 100644
--- a/libgo/go/net/http/cgi/child.go
+++ b/libgo/go/net/http/cgi/child.go
@@ -144,6 +144,7 @@ func Serve(handler http.Handler) error {
 		bufw:   bufio.NewWriter(os.Stdout),
 	}
 	handler.ServeHTTP(rw, req)
+	rw.Write(nil) // make sure a response is sent
 	if err = rw.bufw.Flush(); err != nil {
 		return err
 	}
diff --git a/libgo/go/net/http/cgi/host_test.go b/libgo/go/net/http/cgi/host_test.go
index fec35b72f99..859911f9805 100644
--- a/libgo/go/net/http/cgi/host_test.go
+++ b/libgo/go/net/http/cgi/host_test.go
@@ -41,6 +41,7 @@ func runCgiTest(t *testing.T, h *Handler, httpreq string, expectedMap map[string
 
 	// Make a map to hold the test map that the CGI returns.
 	m := make(map[string]string)
+	m["_body"] = rw.Body.String()
 	linesRead := 0
 readlines:
 	for {
diff --git a/libgo/go/net/http/cgi/matryoshka_test.go b/libgo/go/net/http/cgi/matryoshka_test.go
index 1a44df20401..e1a78c8f62f 100644
--- a/libgo/go/net/http/cgi/matryoshka_test.go
+++ b/libgo/go/net/http/cgi/matryoshka_test.go
@@ -51,6 +51,22 @@ func TestHostingOurselves(t *testing.T) {
 	}
 }
 
+// Test that a child handler only writing headers works.
+func TestChildOnlyHeaders(t *testing.T) {
+	h := &Handler{
+		Path: os.Args[0],
+		Root: "/test.go",
+		Args: []string{"-test.run=TestBeChildCGIProcess"},
+	}
+	expectedMap := map[string]string{
+		"_body": "",
+	}
+	replay := runCgiTest(t, h, "GET /test.go?no-body=1 HTTP/1.0\nHost: example.com\n\n", expectedMap)
+	if expected, got := "X-Test-Value", replay.Header().Get("X-Test-Header"); got != expected {
+		t.Errorf("got a X-Test-Header of %q; expected %q", got, expected)
+	}
+}
+
 // Note: not actually a test.
 func TestBeChildCGIProcess(t *testing.T) {
 	if os.Getenv("REQUEST_METHOD") == "" {
@@ -59,8 +75,11 @@ func TestBeChildCGIProcess(t *testing.T) {
 	}
 	Serve(http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
 		rw.Header().Set("X-Test-Header", "X-Test-Value")
-		fmt.Fprintf(rw, "test=Hello CGI-in-CGI\n")
 		req.ParseForm()
+		if req.FormValue("no-body") == "1" {
+			return
+		}
+		fmt.Fprintf(rw, "test=Hello CGI-in-CGI\n")
 		for k, vv := range req.Form {
 			for _, v := range vv {
 				fmt.Fprintf(rw, "param-%s=%s\n", k, v)
diff --git a/libgo/go/net/http/fs_test.go b/libgo/go/net/http/fs_test.go
index 0409008b675..5aa93ce5837 100644
--- a/libgo/go/net/http/fs_test.go
+++ b/libgo/go/net/http/fs_test.go
@@ -152,12 +152,19 @@ func TestFileServerCleans(t *testing.T) {
 	}
 }
 
+func mustRemoveAll(dir string) {
+	err := os.RemoveAll(dir)
+	if err != nil {
+		panic(err)
+	}
+}
+
 func TestFileServerImplicitLeadingSlash(t *testing.T) {
 	tempDir, err := ioutil.TempDir("", "")
 	if err != nil {
 		t.Fatalf("TempDir: %v", err)
 	}
-	defer os.RemoveAll(tempDir)
+	defer mustRemoveAll(tempDir)
 	if err := ioutil.WriteFile(filepath.Join(tempDir, "foo.txt"), []byte("Hello world"), 0644); err != nil {
 		t.Fatalf("WriteFile: %v", err)
 	}
@@ -172,6 +179,7 @@ func TestFileServerImplicitLeadingSlash(t *testing.T) {
 		if err != nil {
 			t.Fatalf("ReadAll %s: %v", suffix, err)
 		}
+		res.Body.Close()
 		return string(b)
 	}
 	if s := get("/bar/"); !strings.Contains(s, ">foo.txt<") {
diff --git a/libgo/go/net/http/httptest/server.go b/libgo/go/net/http/httptest/server.go
index 8d911f7575b..57cf0c9417d 100644
--- a/libgo/go/net/http/httptest/server.go
+++ b/libgo/go/net/http/httptest/server.go
@@ -13,6 +13,7 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"sync"
 )
 
 // A Server is an HTTP server listening on a system-chosen port on the
@@ -25,6 +26,10 @@ type Server struct {
 	// Config may be changed after calling NewUnstartedServer and
 	// before Start or StartTLS.
 	Config *http.Server
+
+	// wg counts the number of outstanding HTTP requests on this server.
+	// Close blocks until all requests are finished.
+	wg sync.WaitGroup
 }
 
 // historyListener keeps track of all connections that it's ever
@@ -93,6 +98,7 @@ func (s *Server) Start() {
 	}
 	s.Listener = &historyListener{s.Listener, make([]net.Conn, 0)}
 	s.URL = "http://" + s.Listener.Addr().String()
+	s.wrapHandler()
 	go s.Config.Serve(s.Listener)
 	if *serve != "" {
 		fmt.Fprintln(os.Stderr, "httptest: serving on", s.URL)
@@ -118,9 +124,21 @@ func (s *Server) StartTLS() {
 
 	s.Listener = &historyListener{tlsListener, make([]net.Conn, 0)}
 	s.URL = "https://" + s.Listener.Addr().String()
+	s.wrapHandler()
 	go s.Config.Serve(s.Listener)
 }
 
+func (s *Server) wrapHandler() {
+	h := s.Config.Handler
+	if h == nil {
+		h = http.DefaultServeMux
+	}
+	s.Config.Handler = &waitGroupHandler{
+		s: s,
+		h: h,
+	}
+}
+
 // NewTLSServer starts and returns a new Server using TLS.
 // The caller should call Close when finished, to shut it down.
 func NewTLSServer(handler http.Handler) *Server {
@@ -129,9 +147,11 @@ func NewTLSServer(handler http.Handler) *Server {
 	return ts
 }
 
-// Close shuts down the server.
+// Close shuts down the server and blocks until all outstanding
+// requests on this server have completed.
 func (s *Server) Close() {
 	s.Listener.Close()
+	s.wg.Wait()
 }
 
 // CloseClientConnections closes any currently open HTTP connections
@@ -146,6 +166,20 @@ func (s *Server) CloseClientConnections() {
 	}
 }
 
+// waitGroupHandler wraps a handler, incrementing and decrementing a
+// sync.WaitGroup on each request, to enable Server.Close to block
+// until outstanding requests are finished.
+type waitGroupHandler struct {
+	s *Server
+	h http.Handler // non-nil
+}
+
+func (h *waitGroupHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	h.s.wg.Add(1)
+	defer h.s.wg.Done() // a defer, in case ServeHTTP below panics
+	h.h.ServeHTTP(w, r)
+}
+
 // localhostCert is a PEM-encoded TLS cert with SAN DNS names
 // "127.0.0.1" and "[::1]", expiring at the last second of 2049 (the end
 // of ASN.1 time).
diff --git a/libgo/go/net/http/httputil/dump.go b/libgo/go/net/http/httputil/dump.go
index c853066f1cf..892ef4eded0 100644
--- a/libgo/go/net/http/httputil/dump.go
+++ b/libgo/go/net/http/httputil/dump.go
@@ -12,6 +12,7 @@ import (
 	"io/ioutil"
 	"net"
 	"net/http"
+	"net/url"
 	"strings"
 	"time"
 )
@@ -59,6 +60,19 @@ func DumpRequestOut(req *http.Request, body bool) ([]byte, error) {
 		}
 	}
 
+	// Since we're using the actual Transport code to write the request,
+	// switch to http so the Transport doesn't try to do an SSL
+	// negotiation with our dumpConn and its bytes.Buffer & pipe.
+	// The wire format for https and http are the same, anyway.
+	reqSend := req
+	if req.URL.Scheme == "https" {
+		reqSend = new(http.Request)
+		*reqSend = *req
+		reqSend.URL = new(url.URL)
+		*reqSend.URL = *req.URL
+		reqSend.URL.Scheme = "http"
+	}
+
 	// Use the actual Transport code to record what we would send
 	// on the wire, but not using TCP.  Use a Transport with a
 	// customer dialer that returns a fake net.Conn that waits
@@ -79,7 +93,7 @@ func DumpRequestOut(req *http.Request, body bool) ([]byte, error) {
 		},
 	}
 
-	_, err := t.RoundTrip(req)
+	_, err := t.RoundTrip(reqSend)
 
 	req.Body = save
 	if err != nil {
diff --git a/libgo/go/net/http/httputil/dump_test.go b/libgo/go/net/http/httputil/dump_test.go
index 819efb5847b..5afe9ba74e3 100644
--- a/libgo/go/net/http/httputil/dump_test.go
+++ b/libgo/go/net/http/httputil/dump_test.go
@@ -71,6 +71,18 @@ var dumpTests = []dumpTest{
 			"User-Agent: Go http package\r\n" +
 			"Accept-Encoding: gzip\r\n\r\n",
 	},
+
+	// Test that an https URL doesn't try to do an SSL negotiation
+	// with a bytes.Buffer and hang with all goroutines not
+	// runnable.
+	{
+		Req: *mustNewRequest("GET", "https://example.com/foo", nil),
+
+		WantDumpOut: "GET /foo HTTP/1.1\r\n" +
+			"Host: example.com\r\n" +
+			"User-Agent: Go http package\r\n" +
+			"Accept-Encoding: gzip\r\n\r\n",
+	},
 }
 
 func TestDumpRequest(t *testing.T) {
diff --git a/libgo/go/net/http/httputil/persist.go b/libgo/go/net/http/httputil/persist.go
index 32f4662cc0e..507938acac7 100644
--- a/libgo/go/net/http/httputil/persist.go
+++ b/libgo/go/net/http/httputil/persist.go
@@ -383,7 +383,7 @@ func (cc *ClientConn) Read(req *http.Request) (resp *http.Response, err error) {
 	// Make sure body is fully consumed, even if user does not call body.Close
 	if lastbody != nil {
 		// body.Close is assumed to be idempotent and multiple calls to
-		// it should return the error that its first invokation
+		// it should return the error that its first invocation
 		// returned.
 		err = lastbody.Close()
 		if err != nil {
diff --git a/libgo/go/net/http/lex.go b/libgo/go/net/http/lex.go
index 93b67e70176..ffb393ccf6a 100644
--- a/libgo/go/net/http/lex.go
+++ b/libgo/go/net/http/lex.go
@@ -14,14 +14,6 @@ func isSeparator(c byte) bool {
 	return false
 }
 
-func isSpace(c byte) bool {
-	switch c {
-	case ' ', '\t', '\r', '\n':
-		return true
-	}
-	return false
-}
-
 func isCtl(c byte) bool { return (0 <= c && c <= 31) || c == 127 }
 
 func isChar(c byte) bool { return 0 <= c && c <= 127 }
diff --git a/libgo/go/net/http/sniff_test.go b/libgo/go/net/http/sniff_test.go
index 6efa8ce1ca2..8ab72ac23f9 100644
--- a/libgo/go/net/http/sniff_test.go
+++ b/libgo/go/net/http/sniff_test.go
@@ -129,9 +129,10 @@ func TestSniffWriteSize(t *testing.T) {
 	}))
 	defer ts.Close()
 	for _, size := range []int{0, 1, 200, 600, 999, 1000, 1023, 1024, 512 << 10, 1 << 20} {
-		_, err := Get(fmt.Sprintf("%s/?size=%d", ts.URL, size))
+		res, err := Get(fmt.Sprintf("%s/?size=%d", ts.URL, size))
 		if err != nil {
 			t.Fatalf("size %d: %v", size, err)
 		}
+		res.Body.Close()
 	}
 }
diff --git a/libgo/go/net/http/status.go b/libgo/go/net/http/status.go
index b6e2d65c6a5..5af0b77c428 100644
--- a/libgo/go/net/http/status.go
+++ b/libgo/go/net/http/status.go
@@ -43,6 +43,7 @@ const (
 	StatusUnsupportedMediaType         = 415
 	StatusRequestedRangeNotSatisfiable = 416
 	StatusExpectationFailed            = 417
+	StatusTeapot                       = 418
 
 	StatusInternalServerError     = 500
 	StatusNotImplemented          = 501
@@ -90,6 +91,7 @@ var statusText = map[int]string{
 	StatusUnsupportedMediaType:         "Unsupported Media Type",
 	StatusRequestedRangeNotSatisfiable: "Requested Range Not Satisfiable",
 	StatusExpectationFailed:            "Expectation Failed",
+	StatusTeapot:                       "I'm a teapot",
 
 	StatusInternalServerError:     "Internal Server Error",
 	StatusNotImplemented:          "Not Implemented",
diff --git a/libgo/go/net/http/transfer.go b/libgo/go/net/http/transfer.go
index ef9564af9c5..3c8fe7f5b51 100644
--- a/libgo/go/net/http/transfer.go
+++ b/libgo/go/net/http/transfer.go
@@ -383,7 +383,7 @@ func fixTransferEncoding(requestMethod string, header Header) ([]string, error)
 	// chunked encoding must always come first.
 	for _, encoding := range encodings {
 		encoding = strings.ToLower(strings.TrimSpace(encoding))
-		// "identity" encoding is not recored
+		// "identity" encoding is not recorded
 		if encoding == "identity" {
 			break
 		}
diff --git a/libgo/go/net/http/transport.go b/libgo/go/net/http/transport.go
index 3e48abafb5e..09579f8a093 100644
--- a/libgo/go/net/http/transport.go
+++ b/libgo/go/net/http/transport.go
@@ -76,7 +76,9 @@ type Transport struct {
 // ProxyFromEnvironment returns the URL of the proxy to use for a
 // given request, as indicated by the environment variables
 // $HTTP_PROXY and $NO_PROXY (or $http_proxy and $no_proxy).
-// Either URL or an error is returned.
+// An error is returned if the proxy environment is invalid.
+// A nil URL and nil error are returned if no proxy is defined in the
+// environment, or a proxy should not be used for the given request.
 func ProxyFromEnvironment(req *Request) (*url.URL, error) {
 	proxy := getenvEitherCase("HTTP_PROXY")
 	if proxy == "" {
@@ -86,7 +88,7 @@ func ProxyFromEnvironment(req *Request) (*url.URL, error) {
 		return nil, nil
 	}
 	proxyURL, err := url.Parse(proxy)
-	if err != nil {
+	if err != nil || proxyURL.Scheme == "" {
 		if u, err := url.Parse("http://" + proxy); err == nil {
 			proxyURL = u
 			err = nil
diff --git a/libgo/go/net/http/transport_test.go b/libgo/go/net/http/transport_test.go
index 1a629c1727c..cbb3884f9ea 100644
--- a/libgo/go/net/http/transport_test.go
+++ b/libgo/go/net/http/transport_test.go
@@ -16,6 +16,7 @@ import (
 	. "net/http"
 	"net/http/httptest"
 	"net/url"
+	"os"
 	"runtime"
 	"strconv"
 	"strings"
@@ -727,6 +728,36 @@ func TestTransportAltProto(t *testing.T) {
 	}
 }
 
+var proxyFromEnvTests = []struct {
+	env     string
+	wanturl string
+	wanterr error
+}{
+	{"127.0.0.1:8080", "http://127.0.0.1:8080", nil},
+	{"http://127.0.0.1:8080", "http://127.0.0.1:8080", nil},
+	{"https://127.0.0.1:8080", "https://127.0.0.1:8080", nil},
+	{"", "<nil>", nil},
+}
+
+func TestProxyFromEnvironment(t *testing.T) {
+	os.Setenv("HTTP_PROXY", "")
+	os.Setenv("http_proxy", "")
+	os.Setenv("NO_PROXY", "")
+	os.Setenv("no_proxy", "")
+	for i, tt := range proxyFromEnvTests {
+		os.Setenv("HTTP_PROXY", tt.env)
+		req, _ := NewRequest("GET", "http://example.com", nil)
+		url, err := ProxyFromEnvironment(req)
+		if g, e := fmt.Sprintf("%v", err), fmt.Sprintf("%v", tt.wanterr); g != e {
+			t.Errorf("%d. got error = %q, want %q", i, g, e)
+			continue
+		}
+		if got := fmt.Sprintf("%s", url); got != tt.wanturl {
+			t.Errorf("%d. got URL = %q, want %q", i, url, tt.wanturl)
+		}
+	}
+}
+
 // rgz is a gzip quine that uncompresses to itself.
 var rgz = []byte{
 	0x1f, 0x8b, 0x08, 0x08, 0x00, 0x00, 0x00, 0x00,
diff --git a/libgo/go/net/http/triv.go b/libgo/go/net/http/triv.go
index c88a0fbce73..269af0ca3d5 100644
--- a/libgo/go/net/http/triv.go
+++ b/libgo/go/net/http/triv.go
@@ -108,7 +108,6 @@ func DateServer(rw http.ResponseWriter, req *http.Request) {
 		fmt.Fprintf(rw, "fork/exec: %s\n", err)
 		return
 	}
-	defer p.Release()
 	io.Copy(rw, r)
 	wait, err := p.Wait(0)
 	if err != nil {
diff --git a/libgo/go/net/interface.go b/libgo/go/net/interface.go
index 5e7b352ed50..f25d046c171 100644
--- a/libgo/go/net/interface.go
+++ b/libgo/go/net/interface.go
@@ -6,11 +6,7 @@
 
 package net
 
-import (
-	"bytes"
-	"errors"
-	"fmt"
-)
+import "errors"
 
 var (
 	errInvalidInterface         = errors.New("net: invalid interface")
@@ -20,77 +16,6 @@ var (
 	errNoSuchMulticastInterface = errors.New("net: no such multicast interface")
 )
 
-// A HardwareAddr represents a physical hardware address.
-type HardwareAddr []byte
-
-func (a HardwareAddr) String() string {
-	var buf bytes.Buffer
-	for i, b := range a {
-		if i > 0 {
-			buf.WriteByte(':')
-		}
-		fmt.Fprintf(&buf, "%02x", b)
-	}
-	return buf.String()
-}
-
-// ParseMAC parses s as an IEEE 802 MAC-48, EUI-48, or EUI-64 using one of the
-// following formats:
-//   01:23:45:67:89:ab
-//   01:23:45:67:89:ab:cd:ef
-//   01-23-45-67-89-ab
-//   01-23-45-67-89-ab-cd-ef
-//   0123.4567.89ab
-//   0123.4567.89ab.cdef
-func ParseMAC(s string) (hw HardwareAddr, err error) {
-	if len(s) < 14 {
-		goto error
-	}
-
-	if s[2] == ':' || s[2] == '-' {
-		if (len(s)+1)%3 != 0 {
-			goto error
-		}
-		n := (len(s) + 1) / 3
-		if n != 6 && n != 8 {
-			goto error
-		}
-		hw = make(HardwareAddr, n)
-		for x, i := 0, 0; i < n; i++ {
-			var ok bool
-			if hw[i], ok = xtoi2(s[x:], s[2]); !ok {
-				goto error
-			}
-			x += 3
-		}
-	} else if s[4] == '.' {
-		if (len(s)+1)%5 != 0 {
-			goto error
-		}
-		n := 2 * (len(s) + 1) / 5
-		if n != 6 && n != 8 {
-			goto error
-		}
-		hw = make(HardwareAddr, n)
-		for x, i := 0, 0; i < n; i += 2 {
-			var ok bool
-			if hw[i], ok = xtoi2(s[x:x+2], 0); !ok {
-				goto error
-			}
-			if hw[i+1], ok = xtoi2(s[x+2:], s[4]); !ok {
-				goto error
-			}
-			x += 5
-		}
-	} else {
-		goto error
-	}
-	return hw, nil
-
-error:
-	return nil, errors.New("invalid MAC address: " + s)
-}
-
 // Interface represents a mapping between network interface name
 // and index.  It also represents network interface facility
 // information.
diff --git a/libgo/go/net/interface_test.go b/libgo/go/net/interface_test.go
index 769414e0eef..0a33bfdb517 100644
--- a/libgo/go/net/interface_test.go
+++ b/libgo/go/net/interface_test.go
@@ -6,8 +6,6 @@ package net
 
 import (
 	"bytes"
-	"reflect"
-	"strings"
 	"testing"
 )
 
@@ -96,46 +94,3 @@ func testMulticastAddrs(t *testing.T, ifmat []Addr) {
 		}
 	}
 }
-
-var mactests = []struct {
-	in  string
-	out HardwareAddr
-	err string
-}{
-	{"01:23:45:67:89:AB", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab}, ""},
-	{"01-23-45-67-89-AB", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab}, ""},
-	{"0123.4567.89AB", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab}, ""},
-	{"ab:cd:ef:AB:CD:EF", HardwareAddr{0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef}, ""},
-	{"01.02.03.04.05.06", nil, "invalid MAC address"},
-	{"01:02:03:04:05:06:", nil, "invalid MAC address"},
-	{"x1:02:03:04:05:06", nil, "invalid MAC address"},
-	{"01002:03:04:05:06", nil, "invalid MAC address"},
-	{"01:02003:04:05:06", nil, "invalid MAC address"},
-	{"01:02:03004:05:06", nil, "invalid MAC address"},
-	{"01:02:03:04005:06", nil, "invalid MAC address"},
-	{"01:02:03:04:05006", nil, "invalid MAC address"},
-	{"01-02:03:04:05:06", nil, "invalid MAC address"},
-	{"01:02-03-04-05-06", nil, "invalid MAC address"},
-	{"0123:4567:89AF", nil, "invalid MAC address"},
-	{"0123-4567-89AF", nil, "invalid MAC address"},
-	{"01:23:45:67:89:AB:CD:EF", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}, ""},
-	{"01-23-45-67-89-AB-CD-EF", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}, ""},
-	{"0123.4567.89AB.CDEF", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}, ""},
-}
-
-func match(err error, s string) bool {
-	if s == "" {
-		return err == nil
-	}
-	return err != nil && strings.Contains(err.Error(), s)
-}
-
-func TestParseMAC(t *testing.T) {
-	for _, tt := range mactests {
-		out, err := ParseMAC(tt.in)
-		if !reflect.DeepEqual(out, tt.out) || !match(err, tt.err) {
-			t.Errorf("ParseMAC(%q) = %v, %v, want %v, %v", tt.in, out, err, tt.out,
-				tt.err)
-		}
-	}
-}
diff --git a/libgo/go/net/lookup_plan9.go b/libgo/go/net/lookup_plan9.go
index b08a9fb98e0..2c698304b21 100644
--- a/libgo/go/net/lookup_plan9.go
+++ b/libgo/go/net/lookup_plan9.go
@@ -76,7 +76,7 @@ func lookupProtocol(name string) (proto int, err error) {
 }
 
 func lookupHost(host string) (addrs []string, err error) {
-	// Use /net/cs insead of /net/dns because cs knows about
+	// Use /net/cs instead of /net/dns because cs knows about
 	// host names in local network (e.g. from /lib/ndb/local)
 	lines, err := queryCS("tcp", host, "1")
 	if err != nil {
diff --git a/libgo/go/net/lookup_test.go b/libgo/go/net/lookup_test.go
index 7b9ea844cd4..3a61dfb29c2 100644
--- a/libgo/go/net/lookup_test.go
+++ b/libgo/go/net/lookup_test.go
@@ -12,7 +12,7 @@ import (
 	"testing"
 )
 
-var testExternal = flag.Bool("external", false, "allow use of external networks during test")
+var testExternal = flag.Bool("external", true, "allow use of external networks during long test")
 
 func TestGoogleSRV(t *testing.T) {
 	if testing.Short() || !*testExternal {
@@ -78,3 +78,40 @@ func TestGoogleDNSAddr(t *testing.T) {
 		t.Errorf("no results")
 	}
 }
+
+var revAddrTests = []struct {
+	Addr      string
+	Reverse   string
+	ErrPrefix string
+}{
+	{"1.2.3.4", "4.3.2.1.in-addr.arpa.", ""},
+	{"245.110.36.114", "114.36.110.245.in-addr.arpa.", ""},
+	{"::ffff:12.34.56.78", "78.56.34.12.in-addr.arpa.", ""},
+	{"::1", "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa.", ""},
+	{"1::", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.ip6.arpa.", ""},
+	{"1234:567::89a:bcde", "e.d.c.b.a.9.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.6.5.0.4.3.2.1.ip6.arpa.", ""},
+	{"1234:567:fefe:bcbc:adad:9e4a:89a:bcde", "e.d.c.b.a.9.8.0.a.4.e.9.d.a.d.a.c.b.c.b.e.f.e.f.7.6.5.0.4.3.2.1.ip6.arpa.", ""},
+	{"1.2.3", "", "unrecognized address"},
+	{"1.2.3.4.5", "", "unrecognized address"},
+	{"1234:567:bcbca::89a:bcde", "", "unrecognized address"},
+	{"1234:567::bcbc:adad::89a:bcde", "", "unrecognized address"},
+}
+
+func TestReverseAddress(t *testing.T) {
+	for i, tt := range revAddrTests {
+		a, err := reverseaddr(tt.Addr)
+		if len(tt.ErrPrefix) > 0 && err == nil {
+			t.Errorf("#%d: expected %q, got <nil> (error)", i, tt.ErrPrefix)
+			continue
+		}
+		if len(tt.ErrPrefix) == 0 && err != nil {
+			t.Errorf("#%d: expected <nil>, got %q (error)", i, err)
+		}
+		if err != nil && err.(*DNSError).Err != tt.ErrPrefix {
+			t.Errorf("#%d: expected %q, got %q (mismatched error)", i, tt.ErrPrefix, err.(*DNSError).Err)
+		}
+		if a != tt.Reverse {
+			t.Errorf("#%d: expected %q, got %q (reverse address)", i, tt.Reverse, a)
+		}
+	}
+}
diff --git a/libgo/go/net/mac.go b/libgo/go/net/mac.go
new file mode 100644
index 00000000000..e0637d00b74
--- /dev/null
+++ b/libgo/go/net/mac.go
@@ -0,0 +1,84 @@
+// Copyright 2011 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.
+
+// MAC address manipulations
+
+package net
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+)
+
+// A HardwareAddr represents a physical hardware address.
+type HardwareAddr []byte
+
+func (a HardwareAddr) String() string {
+	var buf bytes.Buffer
+	for i, b := range a {
+		if i > 0 {
+			buf.WriteByte(':')
+		}
+		fmt.Fprintf(&buf, "%02x", b)
+	}
+	return buf.String()
+}
+
+// ParseMAC parses s as an IEEE 802 MAC-48, EUI-48, or EUI-64 using one of the
+// following formats:
+//   01:23:45:67:89:ab
+//   01:23:45:67:89:ab:cd:ef
+//   01-23-45-67-89-ab
+//   01-23-45-67-89-ab-cd-ef
+//   0123.4567.89ab
+//   0123.4567.89ab.cdef
+func ParseMAC(s string) (hw HardwareAddr, err error) {
+	if len(s) < 14 {
+		goto error
+	}
+
+	if s[2] == ':' || s[2] == '-' {
+		if (len(s)+1)%3 != 0 {
+			goto error
+		}
+		n := (len(s) + 1) / 3
+		if n != 6 && n != 8 {
+			goto error
+		}
+		hw = make(HardwareAddr, n)
+		for x, i := 0, 0; i < n; i++ {
+			var ok bool
+			if hw[i], ok = xtoi2(s[x:], s[2]); !ok {
+				goto error
+			}
+			x += 3
+		}
+	} else if s[4] == '.' {
+		if (len(s)+1)%5 != 0 {
+			goto error
+		}
+		n := 2 * (len(s) + 1) / 5
+		if n != 6 && n != 8 {
+			goto error
+		}
+		hw = make(HardwareAddr, n)
+		for x, i := 0, 0; i < n; i += 2 {
+			var ok bool
+			if hw[i], ok = xtoi2(s[x:x+2], 0); !ok {
+				goto error
+			}
+			if hw[i+1], ok = xtoi2(s[x+2:], s[4]); !ok {
+				goto error
+			}
+			x += 5
+		}
+	} else {
+		goto error
+	}
+	return hw, nil
+
+error:
+	return nil, errors.New("invalid MAC address: " + s)
+}
diff --git a/libgo/go/net/mac_test.go b/libgo/go/net/mac_test.go
new file mode 100644
index 00000000000..3837e740cf9
--- /dev/null
+++ b/libgo/go/net/mac_test.go
@@ -0,0 +1,54 @@
+// Copyright 2011 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 net
+
+import (
+	"reflect"
+	"strings"
+	"testing"
+)
+
+var mactests = []struct {
+	in  string
+	out HardwareAddr
+	err string
+}{
+	{"01:23:45:67:89:AB", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab}, ""},
+	{"01-23-45-67-89-AB", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab}, ""},
+	{"0123.4567.89AB", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab}, ""},
+	{"ab:cd:ef:AB:CD:EF", HardwareAddr{0xab, 0xcd, 0xef, 0xab, 0xcd, 0xef}, ""},
+	{"01.02.03.04.05.06", nil, "invalid MAC address"},
+	{"01:02:03:04:05:06:", nil, "invalid MAC address"},
+	{"x1:02:03:04:05:06", nil, "invalid MAC address"},
+	{"01002:03:04:05:06", nil, "invalid MAC address"},
+	{"01:02003:04:05:06", nil, "invalid MAC address"},
+	{"01:02:03004:05:06", nil, "invalid MAC address"},
+	{"01:02:03:04005:06", nil, "invalid MAC address"},
+	{"01:02:03:04:05006", nil, "invalid MAC address"},
+	{"01-02:03:04:05:06", nil, "invalid MAC address"},
+	{"01:02-03-04-05-06", nil, "invalid MAC address"},
+	{"0123:4567:89AF", nil, "invalid MAC address"},
+	{"0123-4567-89AF", nil, "invalid MAC address"},
+	{"01:23:45:67:89:AB:CD:EF", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}, ""},
+	{"01-23-45-67-89-AB-CD-EF", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}, ""},
+	{"0123.4567.89AB.CDEF", HardwareAddr{1, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}, ""},
+}
+
+func match(err error, s string) bool {
+	if s == "" {
+		return err == nil
+	}
+	return err != nil && strings.Contains(err.Error(), s)
+}
+
+func TestParseMAC(t *testing.T) {
+	for _, tt := range mactests {
+		out, err := ParseMAC(tt.in)
+		if !reflect.DeepEqual(out, tt.out) || !match(err, tt.err) {
+			t.Errorf("ParseMAC(%q) = %v, %v, want %v, %v", tt.in, out, err, tt.out,
+				tt.err)
+		}
+	}
+}
diff --git a/libgo/go/net/net_test.go b/libgo/go/net/net_test.go
index 69d7ac87880..c1a90de0131 100644
--- a/libgo/go/net/net_test.go
+++ b/libgo/go/net/net_test.go
@@ -5,130 +5,12 @@
 package net
 
 import (
-	"flag"
 	"io"
-	"regexp"
 	"runtime"
 	"testing"
 	"time"
 )
 
-var runErrorTest = flag.Bool("run_error_test", false, "let TestDialError check for dns errors")
-
-type DialErrorTest struct {
-	Net     string
-	Raddr   string
-	Pattern string
-}
-
-var dialErrorTests = []DialErrorTest{
-	{
-		"datakit", "mh/astro/r70",
-		"dial datakit mh/astro/r70: unknown network datakit",
-	},
-	{
-		"tcp", "127.0.0.1:☺",
-		"dial tcp 127.0.0.1:☺: unknown port tcp/☺",
-	},
-	{
-		"tcp", "no-such-name.google.com.:80",
-		"dial tcp no-such-name.google.com.:80: lookup no-such-name.google.com.( on .*)?: no (.*)",
-	},
-	{
-		"tcp", "no-such-name.no-such-top-level-domain.:80",
-		"dial tcp no-such-name.no-such-top-level-domain.:80: lookup no-such-name.no-such-top-level-domain.( on .*)?: no (.*)",
-	},
-	{
-		"tcp", "no-such-name:80",
-		`dial tcp no-such-name:80: lookup no-such-name\.(.*\.)?( on .*)?: no (.*)`,
-	},
-	{
-		"tcp", "mh/astro/r70:http",
-		"dial tcp mh/astro/r70:http: lookup mh/astro/r70: invalid domain name",
-	},
-	{
-		"unix", "/etc/file-not-found",
-		"dial unix /etc/file-not-found: [nN]o such file or directory",
-	},
-	{
-		"unix", "/etc/",
-		"dial unix /etc/: ([pP]ermission denied|socket operation on non-socket|connection refused)",
-	},
-	{
-		"unixpacket", "/etc/file-not-found",
-		"dial unixpacket /etc/file-not-found: no such file or directory",
-	},
-	{
-		"unixpacket", "/etc/",
-		"dial unixpacket /etc/: (permission denied|socket operation on non-socket|connection refused)",
-	},
-}
-
-var duplicateErrorPattern = `dial (.*) dial (.*)`
-
-func TestDialError(t *testing.T) {
-	if !*runErrorTest {
-		t.Logf("test disabled; use --run_error_test to enable")
-		return
-	}
-	for i, tt := range dialErrorTests {
-		c, err := Dial(tt.Net, tt.Raddr)
-		if c != nil {
-			c.Close()
-		}
-		if err == nil {
-			t.Errorf("#%d: nil error, want match for %#q", i, tt.Pattern)
-			continue
-		}
-		s := err.Error()
-		match, _ := regexp.MatchString(tt.Pattern, s)
-		if !match {
-			t.Errorf("#%d: %q, want match for %#q", i, s, tt.Pattern)
-		}
-		match, _ = regexp.MatchString(duplicateErrorPattern, s)
-		if match {
-			t.Errorf("#%d: %q, duplicate error return from Dial", i, s)
-		}
-	}
-}
-
-var revAddrTests = []struct {
-	Addr      string
-	Reverse   string
-	ErrPrefix string
-}{
-	{"1.2.3.4", "4.3.2.1.in-addr.arpa.", ""},
-	{"245.110.36.114", "114.36.110.245.in-addr.arpa.", ""},
-	{"::ffff:12.34.56.78", "78.56.34.12.in-addr.arpa.", ""},
-	{"::1", "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa.", ""},
-	{"1::", "0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.1.0.0.0.ip6.arpa.", ""},
-	{"1234:567::89a:bcde", "e.d.c.b.a.9.8.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.7.6.5.0.4.3.2.1.ip6.arpa.", ""},
-	{"1234:567:fefe:bcbc:adad:9e4a:89a:bcde", "e.d.c.b.a.9.8.0.a.4.e.9.d.a.d.a.c.b.c.b.e.f.e.f.7.6.5.0.4.3.2.1.ip6.arpa.", ""},
-	{"1.2.3", "", "unrecognized address"},
-	{"1.2.3.4.5", "", "unrecognized address"},
-	{"1234:567:bcbca::89a:bcde", "", "unrecognized address"},
-	{"1234:567::bcbc:adad::89a:bcde", "", "unrecognized address"},
-}
-
-func TestReverseAddress(t *testing.T) {
-	for i, tt := range revAddrTests {
-		a, err := reverseaddr(tt.Addr)
-		if len(tt.ErrPrefix) > 0 && err == nil {
-			t.Errorf("#%d: expected %q, got <nil> (error)", i, tt.ErrPrefix)
-			continue
-		}
-		if len(tt.ErrPrefix) == 0 && err != nil {
-			t.Errorf("#%d: expected <nil>, got %q (error)", i, err)
-		}
-		if err != nil && err.(*DNSError).Err != tt.ErrPrefix {
-			t.Errorf("#%d: expected %q, got %q (mismatched error)", i, tt.ErrPrefix, err.(*DNSError).Err)
-		}
-		if a != tt.Reverse {
-			t.Errorf("#%d: expected %q, got %q (reverse address)", i, tt.Reverse, a)
-		}
-	}
-}
-
 func TestShutdown(t *testing.T) {
 	if runtime.GOOS == "plan9" {
 		return
diff --git a/libgo/go/net/rpc/client.go b/libgo/go/net/rpc/client.go
index 34f9ae317e2..f7abf21f157 100644
--- a/libgo/go/net/rpc/client.go
+++ b/libgo/go/net/rpc/client.go
@@ -140,7 +140,7 @@ func (client *Client) input() {
 	}
 	client.mutex.Unlock()
 	client.sending.Unlock()
-	if err != io.EOF || !closing {
+	if err != io.EOF && !closing {
 		log.Println("rpc: client protocol error:", err)
 	}
 }
diff --git a/libgo/go/net/rpc/server.go b/libgo/go/net/rpc/server.go
index 920ae9137a6..1680e2f0d70 100644
--- a/libgo/go/net/rpc/server.go
+++ b/libgo/go/net/rpc/server.go
@@ -13,13 +13,19 @@
 	Only methods that satisfy these criteria will be made available for remote access;
 	other methods will be ignored:
 
-		- the method name is exported, that is, begins with an upper case letter.
-		- the method receiver is exported or local (defined in the package
-		  registering the service).
-		- the method has two arguments, both exported or local types.
+		- the method is exported.
+		- the method has two arguments, both exported (or builtin) types.
 		- the method's second argument is a pointer.
 		- the method has return type error.
 
+	In effect, the method must look schematically like
+
+		func (t *T) MethodName(argType T1, replyType *T2) error
+
+	where T, T1 and T2 can be marshaled by encoding/gob.
+	These requirements apply even if a different codec is used.
+	(In future, these requirements may soften for custom codecs.)
+
 	The method's first argument represents the arguments provided by the caller; the
 	second argument represents the result parameters to be returned to the caller.
 	The method's return value, if non-nil, is passed back as a string that the client
@@ -36,10 +42,12 @@
 	call, a pointer containing the arguments, and a pointer to receive the result
 	parameters.
 
-	Call waits for the remote call to complete; Go launches the call asynchronously
-	and returns a channel that will signal completion.
+	The Call method waits for the remote call to complete while the Go method
+	launches the call asynchronously and signals completion using the Call
+	structure's Done channel.
 
-	Package "gob" is used to transport the data.
+	Unless an explicit codec is set up, package encoding/gob is used to
+	transport the data.
 
 	Here is a simple example.  A server wishes to export an object of type Arith:
 
@@ -256,6 +264,7 @@ func (server *Server) register(rcvr interface{}, name string, useName bool) erro
 		method := s.typ.Method(m)
 		mtype := method.Type
 		mname := method.Name
+		// Method must be exported.
 		if method.PkgPath != "" {
 			continue
 		}
@@ -267,7 +276,7 @@ func (server *Server) register(rcvr interface{}, name string, useName bool) erro
 		// First arg need not be a pointer.
 		argType := mtype.In(1)
 		if !isExportedOrBuiltinType(argType) {
-			log.Println(mname, "argument type not exported or local:", argType)
+			log.Println(mname, "argument type not exported:", argType)
 			continue
 		}
 		// Second arg must be a pointer.
@@ -276,15 +285,17 @@ func (server *Server) register(rcvr interface{}, name string, useName bool) erro
 			log.Println("method", mname, "reply type not a pointer:", replyType)
 			continue
 		}
+		// Reply type must be exported.
 		if !isExportedOrBuiltinType(replyType) {
-			log.Println("method", mname, "reply type not exported or local:", replyType)
+			log.Println("method", mname, "reply type not exported:", replyType)
 			continue
 		}
-		// Method needs one out: error.
+		// Method needs one out.
 		if mtype.NumOut() != 1 {
 			log.Println("method", mname, "has wrong number of outs:", mtype.NumOut())
 			continue
 		}
+		// The return type of the method must be error.
 		if returnType := mtype.Out(0); returnType != typeOfError {
 			log.Println("method", mname, "returns", returnType.String(), "not error")
 			continue
@@ -301,10 +312,10 @@ func (server *Server) register(rcvr interface{}, name string, useName bool) erro
 	return nil
 }
 
-// A value sent as a placeholder for the response when the server receives an invalid request.
-type InvalidRequest struct{}
-
-var invalidRequest = InvalidRequest{}
+// A value sent as a placeholder for the server's response value when the server
+// receives an invalid request. It is never decoded by the client since the Response
+// contains an error when it is used.
+var invalidRequest = struct{}{}
 
 func (server *Server) sendResponse(sending *sync.Mutex, req *Request, reply interface{}, codec ServerCodec, errmsg string) {
 	resp := server.getResponse()
diff --git a/libgo/go/net/sockoptip_netbsd.go b/libgo/go/net/sockoptip_netbsd.go
new file mode 100644
index 00000000000..446d92aa343
--- /dev/null
+++ b/libgo/go/net/sockoptip_netbsd.go
@@ -0,0 +1,39 @@
+// 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.
+
+// IP-level socket options for NetBSD
+
+package net
+
+import "syscall"
+
+func ipv4MulticastInterface(fd *netFD) (*Interface, error) {
+	// TODO: Implement this
+	return nil, syscall.EAFNOSUPPORT
+}
+
+func setIPv4MulticastInterface(fd *netFD, ifi *Interface) error {
+	// TODO: Implement this
+	return syscall.EAFNOSUPPORT
+}
+
+func ipv4MulticastLoopback(fd *netFD) (bool, error) {
+	// TODO: Implement this
+	return false, syscall.EAFNOSUPPORT
+}
+
+func setIPv4MulticastLoopback(fd *netFD, v bool) error {
+	// TODO: Implement this
+	return syscall.EAFNOSUPPORT
+}
+
+func ipv4ReceiveInterface(fd *netFD) (bool, error) {
+	// TODO: Implement this
+	return false, syscall.EAFNOSUPPORT
+}
+
+func setIPv4ReceiveInterface(fd *netFD, v bool) error {
+	// TODO: Implement this
+	return syscall.EAFNOSUPPORT
+}
diff --git a/libgo/go/net/timeout_test.go b/libgo/go/net/timeout_test.go
index bae37c86b2e..ef350f0f946 100644
--- a/libgo/go/net/timeout_test.go
+++ b/libgo/go/net/timeout_test.go
@@ -40,7 +40,7 @@ func testTimeout(t *testing.T, network, addr string, readFrom bool) {
 			errc <- fmt.Errorf("fd.%s on %s %s did not return 0, timeout: %v, %v", what, network, addr, n, err1)
 			return
 		}
-		if dt := t1.Sub(t0); dt < 50*time.Millisecond || dt > 250*time.Millisecond {
+		if dt := t1.Sub(t0); dt < 50*time.Millisecond || !testing.Short() && dt > 250*time.Millisecond {
 			errc <- fmt.Errorf("fd.%s on %s %s took %s, expected 0.1s", what, network, addr, dt)
 			return
 		}
diff --git a/libgo/go/net/udp_test.go b/libgo/go/net/udp_test.go
index 6ba762b1f78..ea5fad41a53 100644
--- a/libgo/go/net/udp_test.go
+++ b/libgo/go/net/udp_test.go
@@ -38,18 +38,18 @@ func testWriteToConn(t *testing.T, raddr string) {
 
 	_, err = c.(*UDPConn).WriteToUDP([]byte("Connection-oriented mode socket"), ra)
 	if err == nil {
-		t.Fatal("WriteToUDP should be failed")
+		t.Fatal("WriteToUDP should fail")
 	}
 	if err != nil && err.(*OpError).Err != ErrWriteToConnected {
-		t.Fatalf("WriteToUDP should be failed as ErrWriteToConnected: %v", err)
+		t.Fatalf("WriteToUDP should fail as ErrWriteToConnected: %v", err)
 	}
 
 	_, err = c.(*UDPConn).WriteTo([]byte("Connection-oriented mode socket"), ra)
 	if err == nil {
-		t.Fatal("WriteTo should be failed")
+		t.Fatal("WriteTo should fail")
 	}
 	if err != nil && err.(*OpError).Err != ErrWriteToConnected {
-		t.Fatalf("WriteTo should be failed as ErrWriteToConnected: %v", err)
+		t.Fatalf("WriteTo should fail as ErrWriteToConnected: %v", err)
 	}
 
 	_, err = c.Write([]byte("Connection-oriented mode socket"))
@@ -82,6 +82,6 @@ func testWriteToPacketConn(t *testing.T, raddr string) {
 
 	_, err = c.(*UDPConn).Write([]byte("Connection-less mode socket"))
 	if err == nil {
-		t.Fatal("Write should be failed")
+		t.Fatal("Write should fail")
 	}
 }
diff --git a/libgo/go/os/doc.go b/libgo/go/os/doc.go
index ef857c0429f..6a531e0d74e 100644
--- a/libgo/go/os/doc.go
+++ b/libgo/go/os/doc.go
@@ -4,6 +4,8 @@
 
 package os
 
+import "time"
+
 // FindProcess looks for a running process by its pid.
 // The Process it returns can be used to obtain information
 // about the underlying operating system process.
@@ -11,6 +13,76 @@ func FindProcess(pid int) (p *Process, err error) {
 	return findProcess(pid)
 }
 
+// StartProcess starts a new process with the program, arguments and attributes
+// specified by name, argv and attr.
+//
+// StartProcess is a low-level interface. The os/exec package provides
+// higher-level interfaces.
+//
+// If there is an error, it will be of type *PathError.
+func StartProcess(name string, argv []string, attr *ProcAttr) (*Process, error) {
+	return startProcess(name, argv, attr)
+}
+
+// Release releases any resources associated with the Process p,
+// rendering it unusable in the future.
+// Release only needs to be called if Wait is not.
+func (p *Process) Release() error {
+	return p.release()
+}
+
+// Kill causes the Process to exit immediately.
+func (p *Process) Kill() error {
+	return p.kill()
+}
+
+// Wait waits for the Process to exit, and then returns a
+// ProcessState describing its status and an error, if any.
+// Wait releases any resources associated with the Process.
+func (p *Process) Wait() (*ProcessState, error) {
+	return p.wait()
+}
+
+// Signal sends a signal to the Process.
+func (p *Process) Signal(sig Signal) error {
+	return p.signal(sig)
+}
+
+// UserTime returns the user CPU time of the exited process and its children.
+func (p *ProcessState) UserTime() time.Duration {
+	return p.userTime()
+}
+
+// SystemTime returns the system CPU time of the exited process and its children.
+func (p *ProcessState) SystemTime() time.Duration {
+	return p.systemTime()
+}
+
+// Exited returns whether the program has exited.
+func (p *ProcessState) Exited() bool {
+	return p.exited()
+}
+
+// Success reports whether the program exited successfully,
+// such as with exit status 0 on Unix.
+func (p *ProcessState) Success() bool {
+	return p.success()
+}
+
+// Sys returns system-dependent exit information about
+// the process.  Convert it to the appropriate underlying
+// type, such as syscall.WaitStatus on Unix, to access its contents.
+func (p *ProcessState) Sys() interface{} {
+	return p.sys()
+}
+
+// SysUsage returns system-dependent resource usage information about
+// the exited process.  Convert it to the appropriate underlying
+// type, such as *syscall.Rusage on Unix, to access its contents.
+func (p *ProcessState) SysUsage() interface{} {
+	return p.sysUsage()
+}
+
 // Hostname returns the host name reported by the kernel.
 func Hostname() (name string, err error) {
 	return hostname()
diff --git a/libgo/go/os/exec.go b/libgo/go/os/exec.go
index 37a0051c5dc..531b87ca556 100644
--- a/libgo/go/os/exec.go
+++ b/libgo/go/os/exec.go
@@ -13,7 +13,7 @@ import (
 type Process struct {
 	Pid    int
 	handle uintptr
-	done   bool // process has been successfuly waited on
+	done   bool // process has been successfully waited on
 }
 
 func newProcess(pid int, handle uintptr) *Process {
diff --git a/libgo/go/os/exec_plan9.go b/libgo/go/os/exec_plan9.go
index 1c9e2b997f8..41cc8c26f4c 100644
--- a/libgo/go/os/exec_plan9.go
+++ b/libgo/go/os/exec_plan9.go
@@ -11,10 +11,7 @@ import (
 	"time"
 )
 
-// StartProcess starts a new process with the program, arguments and attributes
-// specified by name, argv and attr.
-// If there is an error, it will be of type *PathError.
-func StartProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
+func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
 	sysattr := &syscall.ProcAttr{
 		Dir: attr.Dir,
 		Env: attr.Env,
@@ -40,7 +37,7 @@ func (note Plan9Note) String() string {
 	return string(note)
 }
 
-func (p *Process) Signal(sig Signal) error {
+func (p *Process) signal(sig Signal) error {
 	if p.done {
 		return errors.New("os: process already finished")
 	}
@@ -54,8 +51,7 @@ func (p *Process) Signal(sig Signal) error {
 	return e
 }
 
-// Kill causes the Process to exit immediately.
-func (p *Process) Kill() error {
+func (p *Process) kill() error {
 	f, e := OpenFile("/proc/"+itoa(p.Pid)+"/ctl", O_WRONLY, 0)
 	if e != nil {
 		return NewSyscallError("kill", e)
@@ -65,9 +61,7 @@ func (p *Process) Kill() error {
 	return e
 }
 
-// Wait waits for the Process to exit or stop, and then returns a
-// ProcessState describing its status and an error, if any.
-func (p *Process) Wait() (ps *ProcessState, err error) {
+func (p *Process) wait() (ps *ProcessState, err error) {
 	var waitmsg syscall.Waitmsg
 
 	if p.Pid == -1 {
@@ -94,8 +88,7 @@ func (p *Process) Wait() (ps *ProcessState, err error) {
 	return ps, nil
 }
 
-// Release releases any resources associated with the Process.
-func (p *Process) Release() error {
+func (p *Process) release() error {
 	// NOOP for Plan 9.
 	p.Pid = -1
 	// no need for a finalizer anymore
@@ -108,7 +101,7 @@ func findProcess(pid int) (p *Process, err error) {
 	return newProcess(pid, 0), nil
 }
 
-// ProcessState stores information about process as reported by Wait.
+// ProcessState stores information about a process, as reported by Wait.
 type ProcessState struct {
 	pid    int              // The process's id.
 	status *syscall.Waitmsg // System-dependent status info.
@@ -119,40 +112,27 @@ func (p *ProcessState) Pid() int {
 	return p.pid
 }
 
-// Exited returns whether the program has exited.
-func (p *ProcessState) Exited() bool {
+func (p *ProcessState) exited() bool {
 	return p.status.Exited()
 }
 
-// Success reports whether the program exited successfully,
-// such as with exit status 0 on Unix.
-func (p *ProcessState) Success() bool {
+func (p *ProcessState) success() bool {
 	return p.status.ExitStatus() == 0
 }
 
-// Sys returns system-dependent exit information about
-// the process.  Convert it to the appropriate underlying
-// type, such as *syscall.Waitmsg on Plan 9, to access its contents.
-func (p *ProcessState) Sys() interface{} {
+func (p *ProcessState) sys() interface{} {
 	return p.status
 }
 
-// SysUsage returns system-dependent resource usage information about
-// the exited process.  Convert it to the appropriate underlying
-// type, such as *syscall.Waitmsg on Plan 9, to access its contents.
-func (p *ProcessState) SysUsage() interface{} {
+func (p *ProcessState) sysUsage() interface{} {
 	return p.status
 }
 
-// UserTime returns the user CPU time of the exited process and its children.
-// It is always reported as 0 on Windows.
-func (p *ProcessState) UserTime() time.Duration {
+func (p *ProcessState) userTime() time.Duration {
 	return time.Duration(p.status.Time[0]) * time.Millisecond
 }
 
-// SystemTime returns the system CPU time of the exited process and its children.
-// It is always reported as 0 on Windows.
-func (p *ProcessState) SystemTime() time.Duration {
+func (p *ProcessState) systemTime() time.Duration {
 	return time.Duration(p.status.Time[1]) * time.Millisecond
 }
 
diff --git a/libgo/go/os/exec_posix.go b/libgo/go/os/exec_posix.go
index 4a75cb67fb5..70351cfb313 100644
--- a/libgo/go/os/exec_posix.go
+++ b/libgo/go/os/exec_posix.go
@@ -10,14 +10,17 @@ import (
 	"syscall"
 )
 
-// StartProcess starts a new process with the program, arguments and attributes
-// specified by name, argv and attr.
-//
-// StartProcess is a low-level interface. The os/exec package provides
-// higher-level interfaces.
-//
-// If there is an error, it will be of type *PathError.
-func StartProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
+func startProcess(name string, argv []string, attr *ProcAttr) (p *Process, err error) {
+	// Double-check existence of the directory we want
+	// to chdir into.  We can make the error clearer this way.
+	if attr != nil && attr.Dir != "" {
+		if _, err := Stat(attr.Dir); err != nil {
+			pe := err.(*PathError)
+			pe.Op = "chdir"
+			return nil, pe
+		}
+	}
+
 	sysattr := &syscall.ProcAttr{
 		Dir: attr.Dir,
 		Env: attr.Env,
@@ -37,12 +40,11 @@ func StartProcess(name string, argv []string, attr *ProcAttr) (p *Process, err e
 	return newProcess(pid, h), nil
 }
 
-// Kill causes the Process to exit immediately.
-func (p *Process) Kill() error {
+func (p *Process) kill() error {
 	return p.Signal(Kill)
 }
 
-// ProcessState stores information about process as reported by Wait.
+// ProcessState stores information about a process, as reported by Wait.
 type ProcessState struct {
 	pid    int                // The process's id.
 	status syscall.WaitStatus // System-dependent status info.
@@ -54,28 +56,19 @@ func (p *ProcessState) Pid() int {
 	return p.pid
 }
 
-// Exited returns whether the program has exited.
-func (p *ProcessState) Exited() bool {
+func (p *ProcessState) exited() bool {
 	return p.status.Exited()
 }
 
-// Success reports whether the program exited successfully,
-// such as with exit status 0 on Unix.
-func (p *ProcessState) Success() bool {
+func (p *ProcessState) success() bool {
 	return p.status.ExitStatus() == 0
 }
 
-// Sys returns system-dependent exit information about
-// the process.  Convert it to the appropriate underlying
-// type, such as syscall.WaitStatus on Unix, to access its contents.
-func (p *ProcessState) Sys() interface{} {
+func (p *ProcessState) sys() interface{} {
 	return p.status
 }
 
-// SysUsage returns system-dependent resource usage information about
-// the exited process.  Convert it to the appropriate underlying
-// type, such as *syscall.Rusage on Unix, to access its contents.
-func (p *ProcessState) SysUsage() interface{} {
+func (p *ProcessState) sysUsage() interface{} {
 	return p.rusage
 }
 
diff --git a/libgo/go/os/exec_unix.go b/libgo/go/os/exec_unix.go
index 8d000e9ef15..ecfe5353bc1 100644
--- a/libgo/go/os/exec_unix.go
+++ b/libgo/go/os/exec_unix.go
@@ -13,9 +13,7 @@ import (
 	"time"
 )
 
-// Wait waits for the Process to exit or stop, and then returns a
-// ProcessState describing its status and an error, if any.
-func (p *Process) Wait() (ps *ProcessState, err error) {
+func (p *Process) wait() (ps *ProcessState, err error) {
 	if p.Pid == -1 {
 		return nil, syscall.EINVAL
 	}
@@ -36,8 +34,7 @@ func (p *Process) Wait() (ps *ProcessState, err error) {
 	return ps, nil
 }
 
-// Signal sends a signal to the Process.
-func (p *Process) Signal(sig Signal) error {
+func (p *Process) signal(sig Signal) error {
 	if p.done {
 		return errors.New("os: process already finished")
 	}
@@ -51,8 +48,7 @@ func (p *Process) Signal(sig Signal) error {
 	return nil
 }
 
-// Release releases any resources associated with the Process.
-func (p *Process) Release() error {
+func (p *Process) release() error {
 	// NOOP for unix.
 	p.Pid = -1
 	// no need for a finalizer anymore
@@ -65,12 +61,10 @@ func findProcess(pid int) (p *Process, err error) {
 	return newProcess(pid, 0), nil
 }
 
-// UserTime returns the user CPU time of the exited process and its children.
-func (p *ProcessState) UserTime() time.Duration {
+func (p *ProcessState) userTime() time.Duration {
 	return time.Duration(p.rusage.Utime.Nano()) * time.Nanosecond
 }
 
-// SystemTime returns the system CPU time of the exited process and its children.
-func (p *ProcessState) SystemTime() time.Duration {
+func (p *ProcessState) systemTime() time.Duration {
 	return time.Duration(p.rusage.Stime.Nano()) * time.Nanosecond
 }
diff --git a/libgo/go/os/exec_windows.go b/libgo/go/os/exec_windows.go
index dab0dc97571..5beca4a6509 100644
--- a/libgo/go/os/exec_windows.go
+++ b/libgo/go/os/exec_windows.go
@@ -12,9 +12,7 @@ import (
 	"unsafe"
 )
 
-// Wait waits for the Process to exit or stop, and then returns a
-// ProcessState describing its status and an error, if any.
-func (p *Process) Wait() (ps *ProcessState, err error) {
+func (p *Process) wait() (ps *ProcessState, err error) {
 	s, e := syscall.WaitForSingleObject(syscall.Handle(p.handle), syscall.INFINITE)
 	switch s {
 	case syscall.WAIT_OBJECT_0:
@@ -29,12 +27,22 @@ func (p *Process) Wait() (ps *ProcessState, err error) {
 	if e != nil {
 		return nil, NewSyscallError("GetExitCodeProcess", e)
 	}
+	var u syscall.Rusage
+	e = syscall.GetProcessTimes(syscall.Handle(p.handle), &u.CreationTime, &u.ExitTime, &u.KernelTime, &u.UserTime)
+	if e != nil {
+		return nil, NewSyscallError("GetProcessTimes", e)
+	}
 	p.done = true
-	return &ProcessState{p.Pid, syscall.WaitStatus{Status: s, ExitCode: ec}, new(syscall.Rusage)}, nil
+	// NOTE(brainman): It seems that sometimes process is not dead
+	// when WaitForSingleObject returns. But we do not know any
+	// other way to wait for it. Sleeping for a while seems to do
+	// the trick sometimes. So we will sleep and smell the roses.
+	defer time.Sleep(5 * time.Millisecond)
+	defer p.Release()
+	return &ProcessState{p.Pid, syscall.WaitStatus{ExitCode: ec}, &u}, nil
 }
 
-// Signal sends a signal to the Process.
-func (p *Process) Signal(sig Signal) error {
+func (p *Process) signal(sig Signal) error {
 	if p.done {
 		return errors.New("os: process already finished")
 	}
@@ -46,8 +54,7 @@ func (p *Process) Signal(sig Signal) error {
 	return syscall.Errno(syscall.EWINDOWS)
 }
 
-// Release releases any resources associated with the Process.
-func (p *Process) Release() error {
+func (p *Process) release() error {
 	if p.handle == uintptr(syscall.InvalidHandle) {
 		return syscall.EINVAL
 	}
@@ -85,14 +92,15 @@ func init() {
 	}
 }
 
-// UserTime returns the user CPU time of the exited process and its children.
-// For now, it is always reported as 0 on Windows.
-func (p *ProcessState) UserTime() time.Duration {
-	return 0
+func ftToDuration(ft *syscall.Filetime) time.Duration {
+	n := int64(ft.HighDateTime)<<32 + int64(ft.LowDateTime) // in 100-nanosecond intervals
+	return time.Duration(n*100) * time.Nanosecond
+}
+
+func (p *ProcessState) userTime() time.Duration {
+	return ftToDuration(&p.rusage.UserTime)
 }
 
-// SystemTime returns the system CPU time of the exited process and its children.
-// For now, it is always reported as 0 on Windows.
-func (p *ProcessState) SystemTime() time.Duration {
-	return 0
+func (p *ProcessState) systemTime() time.Duration {
+	return ftToDuration(&p.rusage.KernelTime)
 }
diff --git a/libgo/go/os/file.go b/libgo/go/os/file.go
index 1c3d0172d34..4acf35d6755 100644
--- a/libgo/go/os/file.go
+++ b/libgo/go/os/file.go
@@ -25,7 +25,7 @@
 //	open file.go: no such file or directory
 //
 // The file's data can then be read into a slice of bytes. Read and
-// Write take their byte counts from the length of the artument slice.
+// Write take their byte counts from the length of the argument slice.
 //
 //	data := make([]byte, 100)
 //	count, err := file.Read(data)
diff --git a/libgo/go/os/os_test.go b/libgo/go/os/os_test.go
index cff35fcef75..aa01669a5da 100644
--- a/libgo/go/os/os_test.go
+++ b/libgo/go/os/os_test.go
@@ -528,7 +528,6 @@ func exec(t *testing.T, dir, cmd string, args []string, expect string) {
 	if err != nil {
 		t.Fatalf("StartProcess: %v", err)
 	}
-	defer p.Release()
 	w.Close()
 
 	var b bytes.Buffer
@@ -846,7 +845,6 @@ func run(t *testing.T, cmd []string) string {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer p.Release()
 	w.Close()
 
 	var b bytes.Buffer
@@ -1012,3 +1010,38 @@ func TestNilProcessStateString(t *testing.T) {
 		t.Errorf("(*ProcessState)(nil).String() = %q, want %q", s, "<nil>")
 	}
 }
+
+func TestSameFile(t *testing.T) {
+	fa, err := Create("a")
+	if err != nil {
+		t.Fatalf("Create(a): %v", err)
+	}
+	defer Remove(fa.Name())
+	fa.Close()
+	fb, err := Create("b")
+	if err != nil {
+		t.Fatalf("Create(b): %v", err)
+	}
+	defer Remove(fb.Name())
+	fb.Close()
+
+	ia1, err := Stat("a")
+	if err != nil {
+		t.Fatalf("Stat(a): %v", err)
+	}
+	ia2, err := Stat("a")
+	if err != nil {
+		t.Fatalf("Stat(a): %v", err)
+	}
+	if !SameFile(ia1, ia2) {
+		t.Errorf("files should be same")
+	}
+
+	ib, err := Stat("b")
+	if err != nil {
+		t.Fatalf("Stat(b): %v", err)
+	}
+	if SameFile(ia1, ib) {
+		t.Errorf("files should be different")
+	}
+}
diff --git a/libgo/go/path/filepath/path.go b/libgo/go/path/filepath/path.go
index f468d33264b..cfe46981f13 100644
--- a/libgo/go/path/filepath/path.go
+++ b/libgo/go/path/filepath/path.go
@@ -139,6 +139,7 @@ func FromSlash(path string) string {
 
 // SplitList splits a list of paths joined by the OS-specific ListSeparator,
 // usually found in PATH or GOPATH environment variables.
+// Unlike strings.Split, SplitList returns an empty slice when passed an empty string.
 func SplitList(path string) []string {
 	if path == "" {
 		return []string{}
diff --git a/libgo/go/path/filepath/path_plan9.go b/libgo/go/path/filepath/path_plan9.go
index 17b873f1a9b..cf028a75c52 100644
--- a/libgo/go/path/filepath/path_plan9.go
+++ b/libgo/go/path/filepath/path_plan9.go
@@ -17,7 +17,7 @@ func VolumeName(path string) string {
 	return ""
 }
 
-// HasPrefix tests whether the path p begins with prefix.
+// HasPrefix exists for historical compatibility and should not be used.
 func HasPrefix(p, prefix string) bool {
 	return strings.HasPrefix(p, prefix)
 }
diff --git a/libgo/go/path/filepath/path_unix.go b/libgo/go/path/filepath/path_unix.go
index c5ac71efe21..305e307272f 100644
--- a/libgo/go/path/filepath/path_unix.go
+++ b/libgo/go/path/filepath/path_unix.go
@@ -19,7 +19,7 @@ func VolumeName(path string) string {
 	return ""
 }
 
-// HasPrefix tests whether the path p begins with prefix.
+// HasPrefix exists for historical compatibility and should not be used.
 func HasPrefix(p, prefix string) bool {
 	return strings.HasPrefix(p, prefix)
 }
diff --git a/libgo/go/path/filepath/path_windows.go b/libgo/go/path/filepath/path_windows.go
index 9692fd978c5..1d1d23bfe7c 100644
--- a/libgo/go/path/filepath/path_windows.go
+++ b/libgo/go/path/filepath/path_windows.go
@@ -67,8 +67,7 @@ func VolumeName(path string) (v string) {
 	return ""
 }
 
-// HasPrefix tests whether the path p begins with prefix.
-// It ignores case while comparing.
+// HasPrefix exists for historical compatibility and should not be used.
 func HasPrefix(p, prefix string) bool {
 	if strings.HasPrefix(p, prefix) {
 		return true
diff --git a/libgo/go/reflect/all_test.go b/libgo/go/reflect/all_test.go
index 557fb8e843e..56744a514bc 100644
--- a/libgo/go/reflect/all_test.go
+++ b/libgo/go/reflect/all_test.go
@@ -629,6 +629,13 @@ type DeepEqualTest struct {
 	eq   bool
 }
 
+// Simple functions for DeepEqual tests.
+var (
+	fn1 func()             // nil.
+	fn2 func()             // nil.
+	fn3 = func() { fn1() } // Not nil.
+)
+
 var deepEqualTests = []DeepEqualTest{
 	// Equalities
 	{1, 1, true},
@@ -641,6 +648,7 @@ var deepEqualTests = []DeepEqualTest{
 	{Basic{1, 0.5}, Basic{1, 0.5}, true},
 	{error(nil), error(nil), true},
 	{map[int]string{1: "one", 2: "two"}, map[int]string{2: "two", 1: "one"}, true},
+	{fn1, fn2, true},
 
 	// Inequalities
 	{1, 2, false},
@@ -658,6 +666,8 @@ var deepEqualTests = []DeepEqualTest{
 	{map[int]string{2: "two", 1: "one"}, map[int]string{1: "one"}, false},
 	{nil, 1, false},
 	{1, nil, false},
+	{fn1, fn3, false},
+	{fn3, fn3, false},
 
 	// Nil vs empty: not the same.
 	{[]int{}, []int(nil), false},
@@ -1737,3 +1747,15 @@ func isValid(v Value) {
 		panic("zero Value")
 	}
 }
+
+func TestAlias(t *testing.T) {
+	x := string("hello")
+	v := ValueOf(&x).Elem()
+	oldvalue := v.Interface()
+	v.SetString("world")
+	newvalue := v.Interface()
+
+	if oldvalue != "hello" || newvalue != "world" {
+		t.Errorf("aliasing: old=%q new=%q, want hello, world", oldvalue, newvalue)
+	}
+}
diff --git a/libgo/go/reflect/deepequal.go b/libgo/go/reflect/deepequal.go
index df5ec0a6099..c12e90f36cc 100644
--- a/libgo/go/reflect/deepequal.go
+++ b/libgo/go/reflect/deepequal.go
@@ -108,6 +108,12 @@ func deepValueEqual(v1, v2 Value, visited map[uintptr]*visit, depth int) (b bool
 			}
 		}
 		return true
+	case Func:
+		if v1.IsNil() && v2.IsNil() {
+			return true
+		}
+		// Can't do better than this:
+		return false
 	default:
 		// Normal equality suffices
 		return valueInterface(v1, false) == valueInterface(v2, false)
@@ -117,8 +123,8 @@ func deepValueEqual(v1, v2 Value, visited map[uintptr]*visit, depth int) (b bool
 }
 
 // DeepEqual tests for deep equality. It uses normal == equality where possible
-// but will scan members of arrays, slices, and fields of structs. It correctly
-// handles recursive types.
+// but will scan members of arrays, slices, maps, and fields of structs. It correctly
+// handles recursive types. Functions are equal only if they are both nil.
 func DeepEqual(a1, a2 interface{}) bool {
 	if a1 == nil || a2 == nil {
 		return a1 == a2
diff --git a/libgo/go/reflect/type.go b/libgo/go/reflect/type.go
index 9568e41136f..b1dd0a1fecd 100644
--- a/libgo/go/reflect/type.go
+++ b/libgo/go/reflect/type.go
@@ -12,7 +12,7 @@
 // for that type.
 //
 // See "The Laws of Reflection" for an introduction to reflection in Go:
-// http://blog.golang.org/2011/09/laws-of-reflection.html
+// http://golang.org/doc/articles/laws_of_reflection.html
 package reflect
 
 import (
diff --git a/libgo/go/reflect/value.go b/libgo/go/reflect/value.go
index ab56bdf56b6..b490e99f409 100644
--- a/libgo/go/reflect/value.go
+++ b/libgo/go/reflect/value.go
@@ -792,13 +792,15 @@ func (v Value) CanInterface() bool {
 	return v.flag&(flagMethod|flagRO) == 0
 }
 
-// Interface returns v's value as an interface{}.
+// Interface returns v's current value as an interface{}.
+// It is equivalent to:
+//	var i interface{} = (v's underlying value)
 // If v is a method obtained by invoking Value.Method
 // (as opposed to Type.Method), Interface cannot return an
 // interface value, so it panics.
 // It also panics if the Value was obtained by accessing
 // unexported struct fields.
-func (v Value) Interface() interface{} {
+func (v Value) Interface() (i interface{}) {
 	return valueInterface(v, true)
 }
 
@@ -834,6 +836,16 @@ func valueInterface(v Value, safe bool) interface{} {
 	var eface emptyInterface
 	eface.typ = v.typ.runtimeType()
 	eface.word = v.iword()
+
+	if v.flag&flagIndir != 0 && v.typ.size > ptrSize {
+		// eface.word is a pointer to the actual data,
+		// which might be changed.  We need to return
+		// a pointer to unchanging data, so make a copy.
+		ptr := unsafe_New(v.typ)
+		memmove(ptr, unsafe.Pointer(eface.word), v.typ.size)
+		eface.word = iword(ptr)
+	}
+
 	return *(*interface{})(unsafe.Pointer(&eface))
 }
 
diff --git a/libgo/go/runtime/pprof/pprof.go b/libgo/go/runtime/pprof/pprof.go
index 099bb6a92f9..f67e8a8f9ae 100644
--- a/libgo/go/runtime/pprof/pprof.go
+++ b/libgo/go/runtime/pprof/pprof.go
@@ -20,8 +20,8 @@ import (
 	"text/tabwriter"
 )
 
-// BUG(rsc): CPU profiling is broken on OS X, due to an Apple kernel bug.
-// For details, see http://code.google.com/p/go/source/detail?r=35b716c94225.
+// BUG(rsc): A bug in the OS X Snow Leopard 64-bit kernel prevents
+// CPU profiling from giving accurate results on that system.
 
 // A Profile is a collection of stack traces showing the call sequences
 // that led to instances of a particular event, such as allocation.
@@ -156,7 +156,7 @@ func (p *Profile) Count() int {
 }
 
 // Add adds the current execution stack to the profile, associated with value.
-// Add stores value in an internal map, so value must be suitable for use as 
+// Add stores value in an internal map, so value must be suitable for use as
 // a map key and will not be garbage collected until the corresponding
 // call to Remove.  Add panics if the profile already contains a stack for value.
 //
diff --git a/libgo/go/runtime/pprof/pprof_test.go b/libgo/go/runtime/pprof/pprof_test.go
index 5f128c01cf1..2dc7aef7e96 100644
--- a/libgo/go/runtime/pprof/pprof_test.go
+++ b/libgo/go/runtime/pprof/pprof_test.go
@@ -7,6 +7,7 @@ package pprof_test
 import (
 	"bytes"
 	"hash/crc32"
+	"os/exec"
 	"runtime"
 	. "runtime/pprof"
 	"strings"
@@ -17,8 +18,16 @@ import (
 func TestCPUProfile(t *testing.T) {
 	switch runtime.GOOS {
 	case "darwin":
-		// see Apple Bug Report #9177434 (copied into change description)
-		return
+		out, err := exec.Command("uname", "-a").CombinedOutput()
+		if err != nil {
+			t.Fatal(err)
+		}
+		vers := string(out)
+		t.Logf("uname -a: %v", vers)
+		if strings.Contains(vers, "Darwin Kernel Version 10.8.0") && strings.Contains(vers, "root:xnu-1504.15.3~1/RELEASE_X86_64") {
+			t.Logf("skipping test on known-broken kernel (64-bit Snow Leopard)")
+			return
+		}
 	case "plan9":
 		// unimplemented
 		return
diff --git a/libgo/go/strconv/extfloat.go b/libgo/go/strconv/extfloat.go
index 64ab84f4554..aa5e5607ca0 100644
--- a/libgo/go/strconv/extfloat.go
+++ b/libgo/go/strconv/extfloat.go
@@ -477,7 +477,7 @@ func (f *extFloat) ShortestDecimal(d *decimal, lower, upper *extFloat) bool {
 // all data is known with a error estimate of ulpBinary*ε.
 func adjustLastDigit(d *decimal, currentDiff, targetDiff, maxDiff, ulpDecimal, ulpBinary uint64) bool {
 	if ulpDecimal < 2*ulpBinary {
-		// Appromixation is too wide.
+		// Approximation is too wide.
 		return false
 	}
 	for currentDiff+ulpDecimal/2+ulpBinary < targetDiff {
diff --git a/libgo/go/strings/example_test.go b/libgo/go/strings/example_test.go
index 0b583411331..daeb85ef6bb 100644
--- a/libgo/go/strings/example_test.go
+++ b/libgo/go/strings/example_test.go
@@ -41,6 +41,7 @@ func ExampleContainsAny() {
 func ExampleCount() {
 	fmt.Println(strings.Count("cheese", "e"))
 	fmt.Println(strings.Count("five", "")) // before & after each rune
+
 	// Output:
 	// 3
 	// 5
diff --git a/libgo/go/sync/example_test.go b/libgo/go/sync/example_test.go
index 1424b1e79e6..15649240035 100644
--- a/libgo/go/sync/example_test.go
+++ b/libgo/go/sync/example_test.go
@@ -5,6 +5,7 @@
 package sync_test
 
 import (
+	"fmt"
 	"net/http"
 	"sync"
 )
@@ -32,3 +33,22 @@ func ExampleWaitGroup() {
 	// Wait for all HTTP fetches to complete.
 	wg.Wait()
 }
+
+func ExampleOnce() {
+	var once sync.Once
+	onceBody := func() {
+		fmt.Printf("Only once\n")
+	}
+	done := make(chan bool)
+	for i := 0; i < 10; i++ {
+		go func() {
+			once.Do(onceBody)
+			done <- true
+		}()
+	}
+	for i := 0; i < 10; i++ {
+		<-done
+	}
+	// Output:
+	// Only once
+}
diff --git a/libgo/go/sync/waitgroup.go b/libgo/go/sync/waitgroup.go
index 3e7d9d3c8f4..0165b1ffb2b 100644
--- a/libgo/go/sync/waitgroup.go
+++ b/libgo/go/sync/waitgroup.go
@@ -11,21 +11,6 @@ import "sync/atomic"
 // goroutines to wait for.  Then each of the goroutines
 // runs and calls Done when finished.  At the same time,
 // Wait can be used to block until all goroutines have finished.
-//
-// For example:
-//
-//   for i := 0; i < n; i++ {
-//       if !condition(i) {
-//           continue
-//       }
-//       wg.Add(1)
-//       go func() {
-//           // Do something.
-//           wg.Done()
-//       }()
-//   }
-//   wg.Wait()
-// 
 type WaitGroup struct {
 	m       Mutex
 	counter int32
diff --git a/libgo/go/syscall/socket.go b/libgo/go/syscall/socket.go
index 7a2e95ca2a2..6d36e3985f3 100644
--- a/libgo/go/syscall/socket.go
+++ b/libgo/go/syscall/socket.go
@@ -217,6 +217,13 @@ func Socketpair(domain, typ, proto int) (fd [2]int, err error) {
 //sys	getsockopt(s int, level int, name int, val uintptr, vallen *Socklen_t) (err error)
 //getsockopt(s int, level int, name int, val *byte, vallen *Socklen_t) int
 
+func GetsockoptByte(fd, level, opt int) (value byte, err error) {
+	var n byte
+	vallen := Socklen_t(1)
+	err = getsockopt(fd, level, opt, uintptr(unsafe.Pointer(&n)), &vallen)
+	return n, err
+}
+
 func GetsockoptInt(fd, level, opt int) (value int, err error) {
 	var n int32
 	vallen := Socklen_t(4)
@@ -254,6 +261,11 @@ func GetsockoptIPv6Mreq(fd, level, opt int) (*IPv6Mreq, error) {
 //sys	setsockopt(s int, level int, name int, val *byte, vallen Socklen_t) (err error)
 //setsockopt(s int, level int, optname int, val *byte, vallen Socklen_t) int
 
+func SetsockoptByte(fd, level, opt int, value byte) (err error) {
+	var n = byte(value)
+	return setsockopt(fd, level, opt, (*byte)(unsafe.Pointer(&n)), 1)
+}
+
 func SetsockoptInt(fd, level, opt int, value int) (err error) {
 	var n = int32(value)
 	return setsockopt(fd, level, opt, (*byte)(unsafe.Pointer(&n)), 4)
diff --git a/libgo/go/testing/example.go b/libgo/go/testing/example.go
index 7f8ff2d0541..671c798760b 100644
--- a/libgo/go/testing/example.go
+++ b/libgo/go/testing/example.go
@@ -19,7 +19,7 @@ type InternalExample struct {
 	Output string
 }
 
-func RunExamples(examples []InternalExample) (ok bool) {
+func RunExamples(matchString func(pat, str string) (bool, error), examples []InternalExample) (ok bool) {
 	ok = true
 
 	var eg InternalExample
@@ -27,6 +27,14 @@ func RunExamples(examples []InternalExample) (ok bool) {
 	stdout, stderr := os.Stdout, os.Stderr
 
 	for _, eg = range examples {
+		matched, err := matchString(*match, eg.Name)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "testing: invalid regexp for -test.run: %s\n", err)
+			os.Exit(1)
+		}
+		if !matched {
+			continue
+		}
 		if *chatty {
 			fmt.Printf("=== RUN: %s\n", eg.Name)
 		}
diff --git a/libgo/go/testing/testing.go b/libgo/go/testing/testing.go
index adc8c09f217..477d2ac23ae 100644
--- a/libgo/go/testing/testing.go
+++ b/libgo/go/testing/testing.go
@@ -99,7 +99,7 @@ var (
 
 	// Report as tests are run; default is silent for success.
 	chatty         = flag.Bool("test.v", false, "verbose: print additional output")
-	match          = flag.String("test.run", "", "regular expression to select tests to run")
+	match          = flag.String("test.run", "", "regular expression to select tests and examples to run")
 	memProfile     = flag.String("test.memprofile", "", "write a memory profile to the named file after execution")
 	memProfileRate = flag.Int("test.memprofilerate", 0, "if >=0, sets runtime.MemProfileRate")
 	cpuProfile     = flag.String("test.cpuprofile", "", "write a cpu profile to the named file during execution")
@@ -280,7 +280,7 @@ func Main(matchString func(pat, str string) (bool, error), tests []InternalTest,
 	before()
 	startAlarm()
 	testOk := RunTests(matchString, tests)
-	exampleOk := RunExamples(examples)
+	exampleOk := RunExamples(matchString, examples)
 	if !testOk || !exampleOk {
 		fmt.Println("FAIL")
 		os.Exit(1)
diff --git a/libgo/go/text/template/doc.go b/libgo/go/text/template/doc.go
index ae91f4a5419..10e0f7fc373 100644
--- a/libgo/go/text/template/doc.go
+++ b/libgo/go/text/template/doc.go
@@ -142,11 +142,6 @@ An argument is a simple value, denoted by one of the following.
 	    .Field1.Key1.Method1.Field2.Key2.Method2
 	  Methods can also be evaluated on variables, including chaining:
 	    $x.Method1.Field
-	- The name of a niladic function-valued struct field of the data,
-	  preceded by a period, such as
-		.Function
-	  Function-valued fields behave like methods (of structs) but do not
-	  pass a receiver.
 	- The name of a niladic function, such as
 		fun
 	  The result is the value of invoking the function, fun(). The return
@@ -155,6 +150,10 @@ An argument is a simple value, denoted by one of the following.
 
 Arguments may evaluate to any type; if they are pointers the implementation
 automatically indirects to the base type when required.
+If an evaluation yields a function value, such as a function-valued
+field of a struct, the function is not invoked automatically, but it
+can be used as a truth value for an if action and the like. To invoke
+it, use the call function, defined below.
 
 A pipeline is a possibly chained sequence of "commands". A command is a simple
 value (argument) or a function or method call, possibly with multiple arguments:
@@ -167,9 +166,6 @@ value (argument) or a function or method call, possibly with multiple arguments:
 		The result is the value of calling the method with the
 		arguments:
 			dot.Method(Argument1, etc.)
-	.Function [Argument...]
-		A function-valued field of a struct works like a method but does
-		not pass the receiver.
 	functionName [Argument...]
 		The result is the value of calling the function associated
 		with the name:
@@ -257,6 +253,17 @@ Predefined global functions are named as follows.
 		first empty argument or the last argument, that is,
 		"and x y" behaves as "if x then y else x". All the
 		arguments are evaluated.
+	call
+		Returns the result of calling the first argument, which
+		must be a function, with the remaining arguments as parameters.
+		Thus "call .X.Y 1 2" is, in Go notation, dot.X.Y(1, 2) where
+		Y is a func-valued field, map entry, or the like.
+		The first argument must be the result of an evaluation
+		that yields a value of function type (as distinct from
+		a predefined function such as print). The function must
+		return either one or two result values, the second of which
+		is of type error. If the arguments don't match the function
+		or the returned error value is non-nil, execution stops.
 	html
 		Returns the escaped HTML equivalent of the textual
 		representation of its arguments.
diff --git a/libgo/go/text/template/exec.go b/libgo/go/text/template/exec.go
index af745286c0b..ad0118e4e68 100644
--- a/libgo/go/text/template/exec.go
+++ b/libgo/go/text/template/exec.go
@@ -421,11 +421,8 @@ func (s *state) evalField(dot reflect.Value, fieldName string, args []parse.Node
 			field := receiver.FieldByIndex(tField.Index)
 			if tField.PkgPath == "" { // field is exported
 				// If it's a function, we must call it.
-				if field.Type().Kind() == reflect.Func {
-					return s.evalCall(dot, field, fieldName, args, final)
-				}
 				if hasArgs {
-					s.errorf("%s is not a method or function but has arguments", fieldName)
+					s.errorf("%s has arguments but cannot be invoked as function", fieldName)
 				}
 				return field
 			}
diff --git a/libgo/go/text/template/exec_test.go b/libgo/go/text/template/exec_test.go
index 159cf5100d9..70ab39cad20 100644
--- a/libgo/go/text/template/exec_test.go
+++ b/libgo/go/text/template/exec_test.go
@@ -60,7 +60,9 @@ type T struct {
 	PSI *[]int
 	NIL *int
 	// Function (not method)
-	Func func(...string) string
+	BinaryFunc      func(string, string) string
+	VariadicFunc    func(...string) string
+	VariadicFuncInt func(int, ...string) string
 	// Template to test evaluation of templates.
 	Tmpl *Template
 }
@@ -120,7 +122,9 @@ var tVal = &T{
 	Err:               errors.New("erroozle"),
 	PI:                newInt(23),
 	PSI:               newIntSlice(21, 22, 23),
-	Func:              func(s ...string) string { return fmt.Sprint("<", strings.Join(s, "+"), ">") },
+	BinaryFunc:        func(a, b string) string { return fmt.Sprintf("[%s=%s]", a, b) },
+	VariadicFunc:      func(s ...string) string { return fmt.Sprint("<", strings.Join(s, "+"), ">") },
+	VariadicFuncInt:   func(a int, s ...string) string { return fmt.Sprint(a, "=<", strings.Join(s, "+"), ">") },
 	Tmpl:              Must(New("x").Parse("test template")), // "x" is the value of .X
 }
 
@@ -300,13 +304,26 @@ var execTests = []execTest{
 		"{{with $x := .}}{{with .SI}}{{$.GetU.TrueFalse $.True}}{{end}}{{end}}",
 		"true", tVal, true},
 
-	// Function call
-	{".Func", "-{{.Func}}-", "-<>-", tVal, true},
-	{".Func2", "-{{.Func `he` `llo`}}-", "-<he+llo>-", tVal, true},
+	// Function call builtin.
+	{".BinaryFunc", "{{call .BinaryFunc `1` `2`}}", "[1=2]", tVal, true},
+	{".VariadicFunc0", "{{call .VariadicFunc}}", "<>", tVal, true},
+	{".VariadicFunc2", "{{call .VariadicFunc `he` `llo`}}", "<he+llo>", tVal, true},
+	{".VariadicFuncInt", "{{call .VariadicFuncInt 33 `he` `llo`}}", "33=<he+llo>", tVal, true},
+	{"if .BinaryFunc call", "{{ if .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{end}}", "[1=2]", tVal, true},
+	{"if not .BinaryFunc call", "{{ if not .BinaryFunc}}{{call .BinaryFunc `1` `2`}}{{else}}No{{end}}", "No", tVal, true},
+
+	// Erroneous function calls (check args).
+	{".BinaryFuncTooFew", "{{call .BinaryFunc `1`}}", "", tVal, false},
+	{".BinaryFuncTooMany", "{{call .BinaryFunc `1` `2` `3`}}", "", tVal, false},
+	{".BinaryFuncBad0", "{{call .BinaryFunc 1 3}}", "", tVal, false},
+	{".BinaryFuncBad1", "{{call .BinaryFunc `1` 3}}", "", tVal, false},
+	{".VariadicFuncBad0", "{{call .VariadicFunc 3}}", "", tVal, false},
+	{".VariadicFuncIntBad0", "{{call .VariadicFuncInt}}", "", tVal, false},
+	{".VariadicFuncIntBad`", "{{call .VariadicFuncInt `x`}}", "", tVal, false},
 
 	// Pipelines.
 	{"pipeline", "-{{.Method0 | .Method2 .U16}}-", "-Method2: 16 M0-", tVal, true},
-	{"pipeline func", "-{{.Func `llo` | .Func `he` }}-", "-<he+<llo>>-", tVal, true},
+	{"pipeline func", "-{{call .VariadicFunc `llo` | call .VariadicFunc `he` }}-", "-<he+<llo>>-", tVal, true},
 
 	// If.
 	{"if true", "{{if true}}TRUE{{end}}", "TRUE", tVal, true},
diff --git a/libgo/go/text/template/funcs.go b/libgo/go/text/template/funcs.go
index d6e4bf1a216..525179cb499 100644
--- a/libgo/go/text/template/funcs.go
+++ b/libgo/go/text/template/funcs.go
@@ -24,6 +24,7 @@ type FuncMap map[string]interface{}
 
 var builtins = FuncMap{
 	"and":      and,
+	"call":     call,
 	"html":     HTMLEscaper,
 	"index":    index,
 	"js":       JSEscaper,
@@ -151,6 +152,53 @@ func length(item interface{}) (int, error) {
 	return 0, fmt.Errorf("len of type %s", v.Type())
 }
 
+// Function invocation
+
+// call returns the result of evaluating the the first argument as a function.
+// The function must return 1 result, or 2 results, the second of which is an error.
+func call(fn interface{}, args ...interface{}) (interface{}, error) {
+	v := reflect.ValueOf(fn)
+	typ := v.Type()
+	if typ.Kind() != reflect.Func {
+		return nil, fmt.Errorf("non-function of type %s", typ)
+	}
+	if !goodFunc(typ) {
+		return nil, fmt.Errorf("function called with %d args; should be 1 or 2", typ.NumOut())
+	}
+	numIn := typ.NumIn()
+	var dddType reflect.Type
+	if typ.IsVariadic() {
+		if len(args) < numIn-1 {
+			return nil, fmt.Errorf("wrong number of args: got %d want at least %d", len(args), numIn-1)
+		}
+		dddType = typ.In(numIn - 1).Elem()
+	} else {
+		if len(args) != numIn {
+			return nil, fmt.Errorf("wrong number of args: got %d want %d", len(args), numIn)
+		}
+	}
+	argv := make([]reflect.Value, len(args))
+	for i, arg := range args {
+		value := reflect.ValueOf(arg)
+		// Compute the expected type. Clumsy because of variadics.
+		var argType reflect.Type
+		if !typ.IsVariadic() || i < numIn-1 {
+			argType = typ.In(i)
+		} else {
+			argType = dddType
+		}
+		if !value.Type().AssignableTo(argType) {
+			return nil, fmt.Errorf("arg %d has type %s; should be %s", i, value.Type(), argType)
+		}
+		argv[i] = reflect.ValueOf(arg)
+	}
+	result := v.Call(argv)
+	if len(result) == 2 {
+		return result[0].Interface(), result[1].Interface().(error)
+	}
+	return result[0].Interface(), nil
+}
+
 // Boolean logic.
 
 func truth(a interface{}) bool {
diff --git a/libgo/go/text/template/multi_test.go b/libgo/go/text/template/multi_test.go
index f205e6be1b4..22dedc4f839 100644
--- a/libgo/go/text/template/multi_test.go
+++ b/libgo/go/text/template/multi_test.go
@@ -265,6 +265,12 @@ func TestRedefinition(t *testing.T) {
 	if tmpl, err = New("tmpl1").Parse(`{{define "test"}}foo{{end}}`); err != nil {
 		t.Fatalf("parse 1: %v", err)
 	}
+	if _, err = tmpl.Parse(`{{define "test"}}bar{{end}}`); err == nil {
+		t.Fatal("expected error")
+	}
+	if !strings.Contains(err.Error(), "redefinition") {
+		t.Fatalf("expected redefinition error; got %v", err)
+	}
 	if _, err = tmpl.New("tmpl2").Parse(`{{define "test"}}bar{{end}}`); err == nil {
 		t.Fatal("expected error")
 	}
diff --git a/libgo/go/text/template/parse/parse.go b/libgo/go/text/template/parse/parse.go
index 35194f7dfdb..d67b3888085 100644
--- a/libgo/go/text/template/parse/parse.go
+++ b/libgo/go/text/template/parse/parse.go
@@ -193,6 +193,8 @@ func (t *Tree) add(treeSet map[string]*Tree) {
 // IsEmptyTree reports whether this tree (node) is empty of everything but space.
 func IsEmptyTree(n Node) bool {
 	switch n := n.(type) {
+	case nil:
+		return true
 	case *ActionNode:
 	case *IfNode:
 	case *ListNode:
diff --git a/libgo/go/text/template/parse/parse_test.go b/libgo/go/text/template/parse/parse_test.go
index efa7d8be742..18c0a8b835e 100644
--- a/libgo/go/text/template/parse/parse_test.go
+++ b/libgo/go/text/template/parse/parse_test.go
@@ -287,6 +287,9 @@ var isEmptyTests = []isEmptyTest{
 }
 
 func TestIsEmpty(t *testing.T) {
+	if !IsEmptyTree(nil) {
+		t.Errorf("nil tree is not empty")
+	}
 	for _, test := range isEmptyTests {
 		tree, err := New("root").Parse(test.input, "", "", make(map[string]*Tree), nil)
 		if err != nil {
diff --git a/libgo/go/text/template/template.go b/libgo/go/text/template/template.go
index 7494f9d8c45..82fc9e5e39d 100644
--- a/libgo/go/text/template/template.go
+++ b/libgo/go/text/template/template.go
@@ -178,10 +178,11 @@ func (t *Template) Parse(text string) (*Template, error) {
 			tmpl = t.New(name)
 		}
 		// Even if t == tmpl, we need to install it in the common.tmpl map.
-		if err := t.associate(tmpl); err != nil {
+		if replace, err := t.associate(tmpl, tree); err != nil {
 			return nil, err
+		} else if replace {
+			tmpl.Tree = tree
 		}
-		tmpl.Tree = tree
 		tmpl.leftDelim = t.leftDelim
 		tmpl.rightDelim = t.rightDelim
 	}
@@ -191,22 +192,23 @@ func (t *Template) Parse(text string) (*Template, error) {
 // associate installs the new template into the group of templates associated
 // with t. It is an error to reuse a name except to overwrite an empty
 // template. The two are already known to share the common structure.
-func (t *Template) associate(new *Template) error {
+// The boolean return value reports wither to store this tree as t.Tree.
+func (t *Template) associate(new *Template, tree *parse.Tree) (bool, error) {
 	if new.common != t.common {
 		panic("internal error: associate not common")
 	}
 	name := new.name
 	if old := t.tmpl[name]; old != nil {
 		oldIsEmpty := parse.IsEmptyTree(old.Root)
-		newIsEmpty := new.Tree != nil && parse.IsEmptyTree(new.Root)
-		if !oldIsEmpty && !newIsEmpty {
-			return fmt.Errorf("template: redefinition of template %q", name)
-		}
+		newIsEmpty := parse.IsEmptyTree(tree.Root)
 		if newIsEmpty {
 			// Whether old is empty or not, new is empty; no reason to replace old.
-			return nil
+			return false, nil
+		}
+		if !oldIsEmpty {
+			return false, fmt.Errorf("template: redefinition of template %q", name)
 		}
 	}
 	t.tmpl[name] = new
-	return nil
+	return true, nil
 }
diff --git a/libgo/go/time/format.go b/libgo/go/time/format.go
index ef6f1f33514..ad52bab216f 100644
--- a/libgo/go/time/format.go
+++ b/libgo/go/time/format.go
@@ -6,14 +6,6 @@ package time
 
 import "errors"
 
-const (
-	numeric = iota
-	alphabetic
-	separator
-	plus
-	minus
-)
-
 // These are predefined layouts for use in Time.Format.
 // The standard time used in the layouts is:
 //	Mon Jan 2 15:04:05 MST 2006
diff --git a/libgo/go/time/sleep_test.go b/libgo/go/time/sleep_test.go
index e572b678419..440d3b42f12 100644
--- a/libgo/go/time/sleep_test.go
+++ b/libgo/go/time/sleep_test.go
@@ -120,8 +120,11 @@ func TestAfterTick(t *testing.T) {
 	t1 := Now()
 	d := t1.Sub(t0)
 	target := Delta * Count
-	if d < target*9/10 || d > target*30/10 {
-		t.Fatalf("%d ticks of %s took %s, expected %s", Count, Delta, d, target)
+	if d < target*9/10 {
+		t.Fatalf("%d ticks of %s too fast: took %s, expected %s", Count, Delta, d, target)
+	}
+	if !testing.Short() && d > target*30/10 {
+		t.Fatalf("%d ticks of %s too slow: took %s, expected %s", Count, Delta, d, target)
 	}
 }
 
diff --git a/libgo/go/time/time.go b/libgo/go/time/time.go
index 709a4226724..f7ded24d292 100644
--- a/libgo/go/time/time.go
+++ b/libgo/go/time/time.go
@@ -152,7 +152,7 @@ func (d Weekday) String() string { return days[d] }
 // rely heavily on division and modulus by positive constants.  For
 // calendrical calculations we want these divisions to round down, even
 // for negative values, so that the remainder is always positive, but
-// Go's division (like most hardware divison instructions) rounds to
+// Go's division (like most hardware division instructions) rounds to
 // zero.  We can still do those computations and then adjust the result
 // for a negative numerator, but it's annoying to write the adjustment
 // over and over.  Instead, we can change to a different epoch so long
@@ -384,6 +384,15 @@ type Duration int64
 
 // Common durations.  There is no definition for units of Day or larger
 // to avoid confusion across daylight savings time zone transitions.
+//
+// To count the number of units in a Duration, divide:
+//	second := time.Second
+//	fmt.Print(int64(second/time.Millisecond)) // prints 1000
+//
+// To convert an integer number of units to a Duration, multiply:
+//	seconds := 10
+//	fmt.Print(time.Duration(seconds)*time.Second) // prints 10s
+//
 const (
 	Nanosecond  Duration = 1
 	Microsecond          = 1000 * Nanosecond
@@ -758,10 +767,6 @@ func (t Time) UnixNano() int64 {
 	return (t.sec+internalToUnix)*1e9 + int64(t.nsec)
 }
 
-type gobError string
-
-func (g gobError) Error() string { return string(g) }
-
 const timeGobVersion byte = 1
 
 // GobEncode implements the gob.GobEncoder interface.
diff --git a/libgo/runtime/go-main.c b/libgo/runtime/go-main.c
index 5871981f2b8..7e8bb9b234f 100644
--- a/libgo/runtime/go-main.c
+++ b/libgo/runtime/go-main.c
@@ -40,7 +40,7 @@ static void mainstart (void *);
 int
 main (int argc, char **argv)
 {
-  runtime_initsig ();
+  runtime_check ();
   runtime_args (argc, (byte **) argv);
   runtime_osinit ();
   runtime_schedinit ();
diff --git a/libgo/runtime/lock_futex.c b/libgo/runtime/lock_futex.c
index cdc12d7c75c..9a533a577a4 100644
--- a/libgo/runtime/lock_futex.c
+++ b/libgo/runtime/lock_futex.c
@@ -118,8 +118,12 @@ runtime_notewakeup(Note *n)
 void
 runtime_notesleep(Note *n)
 {
+	if(runtime_m()->profilehz > 0)
+		runtime_setprof(false);
 	while(runtime_atomicload(&n->key) == 0)
 		runtime_futexsleep(&n->key, 0, -1);
+	if(runtime_m()->profilehz > 0)
+		runtime_setprof(true);
 }
 
 void
@@ -135,14 +139,18 @@ runtime_notetsleep(Note *n, int64 ns)
 	if(runtime_atomicload(&n->key) != 0)
 		return;
 
+	if(runtime_m()->profilehz > 0)
+		runtime_setprof(false);
 	deadline = runtime_nanotime() + ns;
 	for(;;) {
 		runtime_futexsleep(&n->key, 0, ns);
 		if(runtime_atomicload(&n->key) != 0)
-			return;
+			break;
 		now = runtime_nanotime();
 		if(now >= deadline)
-			return;
+			break;
 		ns = deadline - now;
 	}
+	if(runtime_m()->profilehz > 0)
+		runtime_setprof(true);
 }
diff --git a/libgo/runtime/lock_sema.c b/libgo/runtime/lock_sema.c
index b2a8f53be41..8c4b3973bdc 100644
--- a/libgo/runtime/lock_sema.c
+++ b/libgo/runtime/lock_sema.c
@@ -159,7 +159,11 @@ runtime_notesleep(Note *n)
 		return;
 	}
 	// Queued.  Sleep.
+	if(m->profilehz > 0)
+		runtime_setprof(false);
 	runtime_semasleep(-1);
+	if(m->profilehz > 0)
+		runtime_setprof(true);
 }
 
 void
@@ -185,12 +189,16 @@ runtime_notetsleep(Note *n, int64 ns)
 		return;
 	}
 
+	if(m->profilehz > 0)
+		runtime_setprof(false);
 	deadline = runtime_nanotime() + ns;
 	for(;;) {
 		// Registered.  Sleep.
 		if(runtime_semasleep(ns) >= 0) {
 			// Acquired semaphore, semawakeup unregistered us.
 			// Done.
+			if(m->profilehz > 0)
+				runtime_setprof(true);
 			return;
 		}
 
@@ -203,6 +211,9 @@ runtime_notetsleep(Note *n, int64 ns)
 		ns = deadline - now;
 	}
 
+	if(m->profilehz > 0)
+		runtime_setprof(true);
+
 	// Deadline arrived.  Still registered.  Semaphore not acquired.
 	// Want to give up and return, but have to unregister first,
 	// so that any notewakeup racing with the return does not
diff --git a/libgo/runtime/malloc.goc b/libgo/runtime/malloc.goc
index 23641e8298f..3fde250af3b 100644
--- a/libgo/runtime/malloc.goc
+++ b/libgo/runtime/malloc.goc
@@ -277,6 +277,7 @@ runtime_mallocinit(void)
 	uintptr arena_size, bitmap_size;
 	extern byte end[];
 	byte *want;
+	uintptr limit;
 
 	runtime_sizeof_C_MStats = sizeof(MStats);
 
@@ -291,10 +292,12 @@ runtime_mallocinit(void)
 
 	runtime_InitSizes();
 
+	limit = runtime_memlimit();
+
 	// Set up the allocation arena, a contiguous area of memory where
 	// allocated data will be found.  The arena begins with a bitmap large
 	// enough to hold 4 bits per allocated word.
-	if(sizeof(void*) == 8) {
+	if(sizeof(void*) == 8 && (limit == 0 || limit > (1<<30))) {
 		// On a 64-bit machine, allocate from a single contiguous reservation.
 		// 16 GB should be big enough for now.
 		//
@@ -343,6 +346,10 @@ runtime_mallocinit(void)
 		// of address space, which is probably too much in a 32-bit world.
 		bitmap_size = MaxArena32 / (sizeof(void*)*8/4);
 		arena_size = 512<<20;
+		if(limit > 0 && arena_size+bitmap_size > limit) {
+			bitmap_size = (limit / 9) & ~((1<<PageShift) - 1);
+			arena_size = bitmap_size * 8;
+		}
 		
 		// SysReserve treats the address we ask for, end, as a hint,
 		// not as an absolute requirement.  If we ask for the end
@@ -359,6 +366,8 @@ runtime_mallocinit(void)
 		p = runtime_SysReserve(want, bitmap_size + arena_size);
 		if(p == nil)
 			runtime_throw("runtime: cannot reserve arena virtual address space");
+		if((uintptr)p & (((uintptr)1<<PageShift)-1))
+			runtime_printf("runtime: SysReserve returned unaligned address %p; asked for %p", p, (void*)(bitmap_size+arena_size));
 	}
 	if((uintptr)p & (((uintptr)1<<PageShift)-1))
 		runtime_throw("runtime: SysReserve returned unaligned address");
diff --git a/libgo/runtime/mgc0.c b/libgo/runtime/mgc0.c
index d852946cdbb..4aa7c45dcb3 100644
--- a/libgo/runtime/mgc0.c
+++ b/libgo/runtime/mgc0.c
@@ -654,14 +654,6 @@ markfin(void *v)
 	scanblock(v, size);
 }
 
-struct root_list {
-	struct root_list *next;
-	struct root {
-		void *decl;
-		size_t size;
-	} roots[];
-};
-
 static struct root_list* roots;
 
 void
diff --git a/libgo/runtime/mheap.c b/libgo/runtime/mheap.c
index 79359d9dfca..6bf38aa9934 100644
--- a/libgo/runtime/mheap.c
+++ b/libgo/runtime/mheap.c
@@ -326,7 +326,7 @@ MHeap_FreeLocked(MHeap *h, MSpan *s)
 }
 
 // Release (part of) unused memory to OS.
-// Goroutine created in runtime_schedinit.
+// Goroutine created at startup.
 // Loop forever.
 void
 runtime_MHeap_Scavenger(void* dummy)
diff --git a/libgo/runtime/proc.c b/libgo/runtime/proc.c
index d0ae09c45a0..31e8287e704 100644
--- a/libgo/runtime/proc.c
+++ b/libgo/runtime/proc.c
@@ -416,8 +416,6 @@ runtime_schedinit(void)
 	// Can not enable GC until all roots are registered.
 	// mstats.enablegc = 1;
 	m->nomemprof--;
-
-	scvg = __go_go(runtime_MHeap_Scavenger, nil);
 }
 
 extern void main_init(void) __asm__ ("__go_init_main");
@@ -435,6 +433,7 @@ runtime_main(void)
 	// to preserve the lock.
 	runtime_LockOSThread();
 	runtime_sched.init = true;
+	scvg = __go_go(runtime_MHeap_Scavenger, nil);
 	main_init();
 	runtime_sched.init = false;
 	if(!runtime_sched.lockmain)
@@ -548,7 +547,7 @@ mcommoninit(M *m)
 		m->mcache = runtime_allocmcache();
 
 	runtime_callers(1, m->createstack, nelem(m->createstack));
-	
+
 	// Add to runtime_allm so garbage collector doesn't free m
 	// when it is just in a register or thread-local storage.
 	m->alllink = runtime_allm;
@@ -791,10 +790,11 @@ top:
 		mput(m);
 	}
 
-	// Look for deadlock situation: one single active g which happens to be scvg.
-	if(runtime_sched.grunning == 1 && runtime_sched.gwait == 0) {
-		if(scvg->status == Grunning || scvg->status == Gsyscall)
-			runtime_throw("all goroutines are asleep - deadlock!");
+	// Look for deadlock situation.
+	if((scvg == nil && runtime_sched.grunning == 0) ||
+	   (scvg != nil && runtime_sched.grunning == 1 && runtime_sched.gwait == 0 &&
+	    (scvg->status == Grunning || scvg->status == Gsyscall))) {
+		runtime_throw("all goroutines are asleep - deadlock!");
 	}
 
 	m->nextg = nil;
@@ -1135,6 +1135,9 @@ runtime_entersyscall(void)
 {
 	uint32 v;
 
+	if(m->profilehz > 0)
+		runtime_setprof(false);
+
 	// Leave SP around for gc and traceback.
 #ifdef USING_SPLIT_STACK
 	g->gcstack = __splitstack_find(NULL, NULL, &g->gcstack_size,
@@ -1205,6 +1208,9 @@ runtime_exitsyscall(void)
 #endif
 		gp->gcnext_sp = nil;
 		runtime_memclr(gp->gcregs, sizeof gp->gcregs);
+
+		if(m->profilehz > 0)
+			runtime_setprof(true);
 		return;
 	}
 
diff --git a/libgo/runtime/runtime.c b/libgo/runtime/runtime.c
index 7c8c436deeb..78c865ba175 100644
--- a/libgo/runtime/runtime.c
+++ b/libgo/runtime/runtime.c
@@ -184,6 +184,21 @@ runtime_fastrand1(void)
 	return x;
 }
 
+static struct root_list runtime_roots =
+{ NULL,
+  { { &syscall_Envs, sizeof syscall_Envs },
+    { &os_Args, sizeof os_Args },
+    { NULL, 0 } },
+};
+
+void
+runtime_check(void)
+{
+	__go_register_gc_roots(&runtime_roots);
+
+	runtime_initsig ();
+}
+
 int64
 runtime_cputicks(void)
 {
diff --git a/libgo/runtime/runtime.h b/libgo/runtime/runtime.h
index 113bb7163c5..40c59a82777 100644
--- a/libgo/runtime/runtime.h
+++ b/libgo/runtime/runtime.h
@@ -427,6 +427,8 @@ void	runtime_osyield(void);
 void	runtime_LockOSThread(void) __asm__("libgo_runtime.runtime.LockOSThread");
 void	runtime_UnlockOSThread(void) __asm__("libgo_runtime.runtime.UnlockOSThread");
 
+uintptr	runtime_memlimit(void);
+
 // If appropriate, ask the operating system to control whether this
 // thread should receive profiling signals.  This is only necessary on OS X.
 // An operating system should not deliver a profiling signal to a
@@ -441,3 +443,16 @@ void	runtime_time_scan(void (*)(byte*, int64));
 
 void	runtime_setsig(int32, bool, bool);
 #define runtime_setitimer setitimer
+
+void	runtime_check(void);
+
+// A list of global variables that the garbage collector must scan.
+struct root_list {
+	struct root_list *next;
+	struct root {
+		void *decl;
+		size_t size;
+	} roots[];
+};
+
+void	__go_register_gc_roots(struct root_list*);
diff --git a/libgo/runtime/thread-linux.c b/libgo/runtime/thread-linux.c
index 8dd5fc4b481..6a69fb429a4 100644
--- a/libgo/runtime/thread-linux.c
+++ b/libgo/runtime/thread-linux.c
@@ -3,6 +3,16 @@
 // license that can be found in the LICENSE file.
 
 #include "runtime.h"
+#include "defs.h"
+
+// Linux futex.
+//
+//	futexsleep(uint32 *addr, uint32 val)
+//	futexwakeup(uint32 *addr)
+//
+// Futexsleep atomically checks if *addr == val and if so, sleeps on addr.
+// Futexwakeup wakes up threads sleeping on addr.
+// Futexsleep is allowed to wake up spuriously.
 
 #include <errno.h>
 #include <string.h>
diff --git a/libgo/runtime/thread.c b/libgo/runtime/thread.c
index 748a62d59f5..12d009926e3 100644
--- a/libgo/runtime/thread.c
+++ b/libgo/runtime/thread.c
@@ -4,6 +4,8 @@
 
 #include <errno.h>
 #include <signal.h>
+#include <sys/time.h>
+#include <sys/resource.h>
 
 #include "runtime.h"
 #include "go-assert.h"
@@ -138,6 +140,7 @@ runtime_minit(void)
 	byte* stack;
 	size_t stacksize;
 	stack_t ss;
+	sigset_t sigs;
 
 	// Initialize signal handling.
 	runtime_m()->gsignal = runtime_malg(32*1024, &stack, &stacksize);	// OS X wants >=8K, Linux >=2K
@@ -146,4 +149,34 @@ runtime_minit(void)
 	ss.ss_size = stacksize;
 	if(sigaltstack(&ss, nil) < 0)
 		*(int *)0xf1 = 0xf1;
+	if (sigemptyset(&sigs) != 0)
+		runtime_throw("sigemptyset");
+	sigprocmask(SIG_SETMASK, &sigs, nil);
+}
+
+uintptr
+runtime_memlimit(void)
+{
+	struct rlimit rl;
+	uintptr used;
+
+	if(getrlimit(RLIMIT_AS, &rl) != 0)
+		return 0;
+	if(rl.rlim_cur >= 0x7fffffff)
+		return 0;
+
+	// Estimate our VM footprint excluding the heap.
+	// Not an exact science: use size of binary plus
+	// some room for thread stacks.
+	used = (64<<20);
+	if(used >= rl.rlim_cur)
+		return 0;
+
+	// If there's not at least 16 MB left, we're probably
+	// not going to be able to do much.  Treat as no limit.
+	rl.rlim_cur -= used;
+	if(rl.rlim_cur < (16<<20))
+		return 0;
+
+	return rl.rlim_cur - used;
 }