1 files changed, 469 insertions, 0 deletions
diff --git a/libgo/go/runtime/memmove_test.go b/libgo/go/runtime/memmove_test.go
new file mode 100644
index 0000000..74b8753
--- /dev/null
+++ b/libgo/go/runtime/memmove_test.go
@@ -0,0 +1,469 @@
+// Copyright 2013 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 runtime_test
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+	"fmt"
+	"internal/race"
+	. "runtime"
+	"testing"
+)
+
+func TestMemmove(t *testing.T) {
+	t.Parallel()
+	size := 256
+	if testing.Short() {
+		size = 128 + 16
+	}
+	src := make([]byte, size)
+	dst := make([]byte, size)
+	for i := 0; i < size; i++ {
+		src[i] = byte(128 + (i & 127))
+	}
+	for i := 0; i < size; i++ {
+		dst[i] = byte(i & 127)
+	}
+	for n := 0; n <= size; n++ {
+		for x := 0; x <= size-n; x++ { // offset in src
+			for y := 0; y <= size-n; y++ { // offset in dst
+				copy(dst[y:y+n], src[x:x+n])
+				for i := 0; i < y; i++ {
+					if dst[i] != byte(i&127) {
+						t.Fatalf("prefix dst[%d] = %d", i, dst[i])
+					}
+				}
+				for i := y; i < y+n; i++ {
+					if dst[i] != byte(128+((i-y+x)&127)) {
+						t.Fatalf("copied dst[%d] = %d", i, dst[i])
+					}
+					dst[i] = byte(i & 127) // reset dst
+				}
+				for i := y + n; i < size; i++ {
+					if dst[i] != byte(i&127) {
+						t.Fatalf("suffix dst[%d] = %d", i, dst[i])
+					}
+				}
+			}
+		}
+	}
+}
+
+func TestMemmoveAlias(t *testing.T) {
+	t.Parallel()
+	size := 256
+	if testing.Short() {
+		size = 128 + 16
+	}
+	buf := make([]byte, size)
+	for i := 0; i < size; i++ {
+		buf[i] = byte(i)
+	}
+	for n := 0; n <= size; n++ {
+		for x := 0; x <= size-n; x++ { // src offset
+			for y := 0; y <= size-n; y++ { // dst offset
+				copy(buf[y:y+n], buf[x:x+n])
+				for i := 0; i < y; i++ {
+					if buf[i] != byte(i) {
+						t.Fatalf("prefix buf[%d] = %d", i, buf[i])
+					}
+				}
+				for i := y; i < y+n; i++ {
+					if buf[i] != byte(i-y+x) {
+						t.Fatalf("copied buf[%d] = %d", i, buf[i])
+					}
+					buf[i] = byte(i) // reset buf
+				}
+				for i := y + n; i < size; i++ {
+					if buf[i] != byte(i) {
+						t.Fatalf("suffix buf[%d] = %d", i, buf[i])
+					}
+				}
+			}
+		}
+	}
+}
+
+func TestMemmoveLarge0x180000(t *testing.T) {
+	t.Parallel()
+	if race.Enabled {
+		t.Skip("skipping large memmove test under race detector")
+	}
+	testSize(t, 0x180000)
+}
+
+func TestMemmoveOverlapLarge0x120000(t *testing.T) {
+	t.Parallel()
+	if race.Enabled {
+		t.Skip("skipping large memmove test under race detector")
+	}
+	testOverlap(t, 0x120000)
+}
+
+func testSize(t *testing.T, size int) {
+	src := make([]byte, size)
+	dst := make([]byte, size)
+	_, _ = rand.Read(src)
+	_, _ = rand.Read(dst)
+
+	ref := make([]byte, size)
+	copyref(ref, dst)
+
+	for n := size - 50; n > 1; n >>= 1 {
+		for x := 0; x <= size-n; x = x*7 + 1 { // offset in src
+			for y := 0; y <= size-n; y = y*9 + 1 { // offset in dst
+				copy(dst[y:y+n], src[x:x+n])
+				copyref(ref[y:y+n], src[x:x+n])
+				p := cmpb(dst, ref)
+				if p >= 0 {
+					t.Fatalf("Copy failed, copying from src[%d:%d] to dst[%d:%d].\nOffset %d is different, %v != %v", x, x+n, y, y+n, p, dst[p], ref[p])
+				}
+			}
+		}
+	}
+}
+
+func testOverlap(t *testing.T, size int) {
+	src := make([]byte, size)
+	test := make([]byte, size)
+	ref := make([]byte, size)
+	_, _ = rand.Read(src)
+
+	for n := size - 50; n > 1; n >>= 1 {
+		for x := 0; x <= size-n; x = x*7 + 1 { // offset in src
+			for y := 0; y <= size-n; y = y*9 + 1 { // offset in dst
+				// Reset input
+				copyref(test, src)
+				copyref(ref, src)
+				copy(test[y:y+n], test[x:x+n])
+				if y <= x {
+					copyref(ref[y:y+n], ref[x:x+n])
+				} else {
+					copybw(ref[y:y+n], ref[x:x+n])
+				}
+				p := cmpb(test, ref)
+				if p >= 0 {
+					t.Fatalf("Copy failed, copying from src[%d:%d] to dst[%d:%d].\nOffset %d is different, %v != %v", x, x+n, y, y+n, p, test[p], ref[p])
+				}
+			}
+		}
+	}
+
+}
+
+// Forward copy.
+func copyref(dst, src []byte) {
+	for i, v := range src {
+		dst[i] = v
+	}
+}
+
+// Backwards copy
+func copybw(dst, src []byte) {
+	if len(src) == 0 {
+		return
+	}
+	for i := len(src) - 1; i >= 0; i-- {
+		dst[i] = src[i]
+	}
+}
+
+// Returns offset of difference
+func matchLen(a, b []byte, max int) int {
+	a = a[:max]
+	b = b[:max]
+	for i, av := range a {
+		if b[i] != av {
+			return i
+		}
+	}
+	return max
+}
+
+func cmpb(a, b []byte) int {
+	l := matchLen(a, b, len(a))
+	if l == len(a) {
+		return -1
+	}
+	return l
+}
+
+func benchmarkSizes(b *testing.B, sizes []int, fn func(b *testing.B, n int)) {
+	for _, n := range sizes {
+		b.Run(fmt.Sprint(n), func(b *testing.B) {
+			b.SetBytes(int64(n))
+			fn(b, n)
+		})
+	}
+}
+
+var bufSizes = []int{
+	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16,
+	32, 64, 128, 256, 512, 1024, 2048, 4096,
+}
+
+func BenchmarkMemmove(b *testing.B) {
+	benchmarkSizes(b, bufSizes, func(b *testing.B, n int) {
+		x := make([]byte, n)
+		y := make([]byte, n)
+		for i := 0; i < b.N; i++ {
+			copy(x, y)
+		}
+	})
+}
+
+func BenchmarkMemmoveUnalignedDst(b *testing.B) {
+	benchmarkSizes(b, bufSizes, func(b *testing.B, n int) {
+		x := make([]byte, n+1)
+		y := make([]byte, n)
+		for i := 0; i < b.N; i++ {
+			copy(x[1:], y)
+		}
+	})
+}
+
+func BenchmarkMemmoveUnalignedSrc(b *testing.B) {
+	benchmarkSizes(b, bufSizes, func(b *testing.B, n int) {
+		x := make([]byte, n)
+		y := make([]byte, n+1)
+		for i := 0; i < b.N; i++ {
+			copy(x, y[1:])
+		}
+	})
+}
+
+func TestMemclr(t *testing.T) {
+	size := 512
+	if testing.Short() {
+		size = 128 + 16
+	}
+	mem := make([]byte, size)
+	for i := 0; i < size; i++ {
+		mem[i] = 0xee
+	}
+	for n := 0; n < size; n++ {
+		for x := 0; x <= size-n; x++ { // offset in mem
+			MemclrBytes(mem[x : x+n])
+			for i := 0; i < x; i++ {
+				if mem[i] != 0xee {
+					t.Fatalf("overwrite prefix mem[%d] = %d", i, mem[i])
+				}
+			}
+			for i := x; i < x+n; i++ {
+				if mem[i] != 0 {
+					t.Fatalf("failed clear mem[%d] = %d", i, mem[i])
+				}
+				mem[i] = 0xee
+			}
+			for i := x + n; i < size; i++ {
+				if mem[i] != 0xee {
+					t.Fatalf("overwrite suffix mem[%d] = %d", i, mem[i])
+				}
+			}
+		}
+	}
+}
+
+func BenchmarkMemclr(b *testing.B) {
+	for _, n := range []int{5, 16, 64, 256, 4096, 65536} {
+		x := make([]byte, n)
+		b.Run(fmt.Sprint(n), func(b *testing.B) {
+			b.SetBytes(int64(n))
+			for i := 0; i < b.N; i++ {
+				MemclrBytes(x)
+			}
+		})
+	}
+	for _, m := range []int{1, 4, 8, 16, 64} {
+		x := make([]byte, m<<20)
+		b.Run(fmt.Sprint(m, "M"), func(b *testing.B) {
+			b.SetBytes(int64(m << 20))
+			for i := 0; i < b.N; i++ {
+				MemclrBytes(x)
+			}
+		})
+	}
+}
+
+func BenchmarkGoMemclr(b *testing.B) {
+	benchmarkSizes(b, []int{5, 16, 64, 256}, func(b *testing.B, n int) {
+		x := make([]byte, n)
+		for i := 0; i < b.N; i++ {
+			for j := range x {
+				x[j] = 0
+			}
+		}
+	})
+}
+
+func BenchmarkClearFat8(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [8 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat12(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [12 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat16(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [16 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat24(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [24 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat32(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [32 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat40(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [40 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat48(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [48 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat56(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [56 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat64(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [64 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat128(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [128 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat256(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [256 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat512(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [512 / 4]uint32
+		_ = x
+	}
+}
+func BenchmarkClearFat1024(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		var x [1024 / 4]uint32
+		_ = x
+	}
+}
+
+func BenchmarkCopyFat8(b *testing.B) {
+	var x [8 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+func BenchmarkCopyFat12(b *testing.B) {
+	var x [12 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+func BenchmarkCopyFat16(b *testing.B) {
+	var x [16 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+func BenchmarkCopyFat24(b *testing.B) {
+	var x [24 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+func BenchmarkCopyFat32(b *testing.B) {
+	var x [32 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+func BenchmarkCopyFat64(b *testing.B) {
+	var x [64 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+func BenchmarkCopyFat128(b *testing.B) {
+	var x [128 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+func BenchmarkCopyFat256(b *testing.B) {
+	var x [256 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+func BenchmarkCopyFat512(b *testing.B) {
+	var x [512 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+func BenchmarkCopyFat1024(b *testing.B) {
+	var x [1024 / 4]uint32
+	for i := 0; i < b.N; i++ {
+		y := x
+		_ = y
+	}
+}
+
+func BenchmarkIssue18740(b *testing.B) {
+	// This tests that memmove uses one 4-byte load/store to move 4 bytes.
+	// It used to do 2 2-byte load/stores, which leads to a pipeline stall
+	// when we try to read the result with one 4-byte load.
+	var buf [4]byte
+	for j := 0; j < b.N; j++ {
+		s := uint32(0)
+		for i := 0; i < 4096; i += 4 {
+			copy(buf[:], g[i:])
+			s += binary.LittleEndian.Uint32(buf[:])
+		}
+		sink = uint64(s)
+	}
+}
+
+// TODO: 2 byte and 8 byte benchmarks also.
+
+var g [4096]byte