libgo: update to go1.7rc3

Reviewed-on: https://go-review.googlesource.com/25150

From-SVN: r238662

libgo/go/encoding/binary/binary.go

@@ -1,4 +1,4 @@
-// Copyright 2009 The Go Authors.  All rights reserved.
+// Copyright 2009 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.
 
@@ -48,18 +48,24 @@ var BigEndian bigEndian
 
 type littleEndian struct{}
 
-func (littleEndian) Uint16(b []byte) uint16 { return uint16(b[0]) | uint16(b[1])<<8 }
+func (littleEndian) Uint16(b []byte) uint16 {
+	_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
+	return uint16(b[0]) | uint16(b[1])<<8
+}
 
 func (littleEndian) PutUint16(b []byte, v uint16) {
+	_ = b[1] // early bounds check to guarantee safety of writes below
 	b[0] = byte(v)
 	b[1] = byte(v >> 8)
 }
 
 func (littleEndian) Uint32(b []byte) uint32 {
+	_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
 	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
 }
 
 func (littleEndian) PutUint32(b []byte, v uint32) {
+	_ = b[3] // early bounds check to guarantee safety of writes below
 	b[0] = byte(v)
 	b[1] = byte(v >> 8)
 	b[2] = byte(v >> 16)
@@ -67,11 +73,13 @@ func (littleEndian) PutUint32(b []byte, v uint32) {
 }
 
 func (littleEndian) Uint64(b []byte) uint64 {
+	_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
 	return uint64(b[0]) | uint64(b[1])<<8 | uint64(b[2])<<16 | uint64(b[3])<<24 |
 		uint64(b[4])<<32 | uint64(b[5])<<40 | uint64(b[6])<<48 | uint64(b[7])<<56
 }
 
 func (littleEndian) PutUint64(b []byte, v uint64) {
+	_ = b[7] // early bounds check to guarantee safety of writes below
 	b[0] = byte(v)
 	b[1] = byte(v >> 8)
 	b[2] = byte(v >> 16)
@@ -88,18 +96,24 @@ func (littleEndian) GoString() string { return "binary.LittleEndian" }
 
 type bigEndian struct{}
 
-func (bigEndian) Uint16(b []byte) uint16 { return uint16(b[1]) | uint16(b[0])<<8 }
+func (bigEndian) Uint16(b []byte) uint16 {
+	_ = b[1] // bounds check hint to compiler; see golang.org/issue/14808
+	return uint16(b[1]) | uint16(b[0])<<8
+}
 
 func (bigEndian) PutUint16(b []byte, v uint16) {
+	_ = b[1] // early bounds check to guarantee safety of writes below
 	b[0] = byte(v >> 8)
 	b[1] = byte(v)
 }
 
 func (bigEndian) Uint32(b []byte) uint32 {
+	_ = b[3] // bounds check hint to compiler; see golang.org/issue/14808
 	return uint32(b[3]) | uint32(b[2])<<8 | uint32(b[1])<<16 | uint32(b[0])<<24
 }
 
 func (bigEndian) PutUint32(b []byte, v uint32) {
+	_ = b[3] // early bounds check to guarantee safety of writes below
 	b[0] = byte(v >> 24)
 	b[1] = byte(v >> 16)
 	b[2] = byte(v >> 8)
@@ -107,11 +121,13 @@ func (bigEndian) PutUint32(b []byte, v uint32) {
 }
 
 func (bigEndian) Uint64(b []byte) uint64 {
+	_ = b[7] // bounds check hint to compiler; see golang.org/issue/14808
 	return uint64(b[7]) | uint64(b[6])<<8 | uint64(b[5])<<16 | uint64(b[4])<<24 |
 		uint64(b[3])<<32 | uint64(b[2])<<40 | uint64(b[1])<<48 | uint64(b[0])<<56
 }
 
 func (bigEndian) PutUint64(b []byte, v uint64) {
+	_ = b[7] // early bounds check to guarantee safety of writes below
 	b[0] = byte(v >> 56)
 	b[1] = byte(v >> 48)
 	b[2] = byte(v >> 40)
@@ -253,7 +269,7 @@ func Write(w io.Writer, order ByteOrder, data interface{}) error {
 		case *uint8:
 			b[0] = *v
 		case uint8:
-			b[0] = byte(v)
+			b[0] = v
 		case []uint8:
 			bs = v
 		case *int16:

libgo/go/encoding/binary/binary_test.go

@@ -1,4 +1,4 @@
-// Copyright 2009 The Go Authors.  All rights reserved.
+// Copyright 2009 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.
 
@@ -266,7 +266,7 @@ func TestBlankFields(t *testing.T) {
 }
 
 // An attempt to read into a struct with an unexported field will
-// panic.  This is probably not the best choice, but at this point
+// panic. This is probably not the best choice, but at this point
 // anything else would be an API change.
 
 type Unexported struct {
@@ -339,6 +339,33 @@ func TestReadTruncated(t *testing.T) {
 	}
 }
 
+func testUint64SmallSliceLengthPanics() (panicked bool) {
+	defer func() {
+		panicked = recover() != nil
+	}()
+	b := [8]byte{1, 2, 3, 4, 5, 6, 7, 8}
+	LittleEndian.Uint64(b[:4])
+	return false
+}
+
+func testPutUint64SmallSliceLengthPanics() (panicked bool) {
+	defer func() {
+		panicked = recover() != nil
+	}()
+	b := [8]byte{}
+	LittleEndian.PutUint64(b[:4], 0x0102030405060708)
+	return false
+}
+
+func TestEarlyBoundsChecks(t *testing.T) {
+	if testUint64SmallSliceLengthPanics() != true {
+		t.Errorf("binary.LittleEndian.Uint64 expected to panic for small slices, but didn't")
+	}
+	if testPutUint64SmallSliceLengthPanics() != true {
+		t.Errorf("binary.LittleEndian.PutUint64 expected to panic for small slices, but didn't")
+	}
+}
+
 type byteSliceReader struct {
 	remain []byte
 }
@@ -373,8 +400,8 @@ func BenchmarkReadStruct(b *testing.B) {
 		Read(bsr, BigEndian, &t)
 	}
 	b.StopTimer()
-	if !reflect.DeepEqual(s, t) {
-		b.Fatal("no match")
+	if b.N > 0 && !reflect.DeepEqual(s, t) {
+		b.Fatalf("struct doesn't match:\ngot  %v;\nwant %v", t, s)
 	}
 }
 
@@ -405,8 +432,8 @@ func BenchmarkReadInts(b *testing.B) {
 		want.Array[i] = 0
 	}
 	b.StopTimer()
-	if !reflect.DeepEqual(ls, want) {
-		panic("no match")
+	if b.N > 0 && !reflect.DeepEqual(ls, want) {
+		b.Fatalf("struct doesn't match:\ngot  %v;\nwant %v", ls, want)
 	}
 }
 
@@ -427,7 +454,7 @@ func BenchmarkWriteInts(b *testing.B) {
 		Write(w, BigEndian, s.Uint64)
 	}
 	b.StopTimer()
-	if !bytes.Equal(buf.Bytes(), big[:30]) {
+	if b.N > 0 && !bytes.Equal(buf.Bytes(), big[:30]) {
 		b.Fatalf("first half doesn't match: %x %x", buf.Bytes(), big[:30])
 	}
 }

libgo/go/encoding/binary/varint.go

@@ -1,4 +1,4 @@
-// Copyright 2011 The Go Authors.  All rights reserved.
+// 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.