6912521: System.arraycopy works slower than the simple loop for little lengths
Summary: convert small array copies to series of loads and stores
Reviewed-by: kvn, vlivanov
/*
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
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* questions.
*/
/*
* @test
* @bug 6912521
* @summary small array copy as loads/stores
* @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:CompileCommand=dontinline,TestArrayCopyAsLoadsStores::m* -XX:TypeProfileLevel=200 TestArrayCopyAsLoadsStores
* @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement -XX:CompileCommand=dontinline,TestArrayCopyAsLoadsStores::m* -XX:+IgnoreUnrecognizedVMOptions -XX:+StressArrayCopyMacroNode -XX:TypeProfileLevel=200 TestArrayCopyAsLoadsStores
*
*/
import java.lang.annotation.*;
import java.lang.reflect.*;
import java.util.*;
public class TestArrayCopyAsLoadsStores {
public enum ArraySrc {
SMALL,
LARGE,
ZERO
}
public enum ArrayDst {
NONE,
NEW,
SRC
}
static class A {
}
static class B extends A {
}
static final A[] small_a_src = new A[5];
static final A[] large_a_src = new A[10];
static final A[] zero_a_src = new A[0];
static final int[] small_int_src = new int[5];
static final int[] large_int_src = new int[10];
static final int[] zero_int_src = new int[0];
static final Object[] small_object_src = new Object[5];
static Object src;
@Retention(RetentionPolicy.RUNTIME)
@interface Args {
ArraySrc src();
ArrayDst dst() default ArrayDst.NONE;
int[] extra_args() default {};
}
// array clone should be compiled as loads/stores
@Args(src=ArraySrc.SMALL)
static A[] m1() throws CloneNotSupportedException {
return (A[])small_a_src.clone();
}
@Args(src=ArraySrc.SMALL)
static int[] m2() throws CloneNotSupportedException {
return (int[])small_int_src.clone();
}
// new array allocation should be optimized out
@Args(src=ArraySrc.SMALL)
static int m3() throws CloneNotSupportedException {
int[] array_clone = (int[])small_int_src.clone();
return array_clone[0] + array_clone[1] + array_clone[2] +
array_clone[3] + array_clone[4];
}
// should not be compiled as loads/stores
@Args(src=ArraySrc.LARGE)
static int[] m4() throws CloneNotSupportedException {
return (int[])large_int_src.clone();
}
// check that array of length 0 is handled correctly
@Args(src=ArraySrc.ZERO)
static int[] m5() throws CloneNotSupportedException {
return (int[])zero_int_src.clone();
}
// array copy should be compiled as loads/stores
@Args(src=ArraySrc.SMALL, dst=ArrayDst.NEW)
static void m6(int[] src, int[] dest) {
System.arraycopy(src, 0, dest, 0, 5);
}
// array copy should not be compiled as loads/stores
@Args(src=ArraySrc.LARGE, dst=ArrayDst.NEW)
static void m7(int[] src, int[] dest) {
System.arraycopy(src, 0, dest, 0, 10);
}
// array copy should be compiled as loads/stores
@Args(src=ArraySrc.SMALL)
static A[] m8(A[] src) {
src[0] = src[0]; // force null check
A[] dest = new A[5];
System.arraycopy(src, 0, dest, 0, 5);
return dest;
}
// array copy should not be compiled as loads/stores: we would
// need to emit GC barriers
@Args(src=ArraySrc.SMALL, dst=ArrayDst.NEW)
static void m9(A[] src, A[] dest) {
System.arraycopy(src, 0, dest, 0, 5);
}
// overlapping array regions: copy backward
@Args(src=ArraySrc.SMALL, dst=ArrayDst.SRC)
static void m10(int[] src, int[] dest) {
System.arraycopy(src, 0, dest, 1, 4);
}
static boolean m10_check(int[] src, int[] dest) {
boolean failure = false;
for (int i = 0; i < 5; i++) {
int j = Math.max(i - 1, 0);
if (dest[i] != src[j]) {
System.out.println("Test m10 failed for " + i + " src[" + j +"]=" + src[j] + ", dest[" + i + "]=" + dest[i]);
failure = true;
}
}
return failure;
}
// overlapping array regions: copy forward
@Args(src=ArraySrc.SMALL, dst=ArrayDst.SRC)
static void m11(int[] src, int[] dest) {
System.arraycopy(src, 1, dest, 0, 4);
}
static boolean m11_check(int[] src, int[] dest) {
boolean failure = false;
for (int i = 0; i < 5; i++) {
int j = Math.min(i + 1, 4);
if (dest[i] != src[j]) {
System.out.println("Test m11 failed for " + i + " src[" + j +"]=" + src[j] + ", dest[" + i + "]=" + dest[i]);
failure = true;
}
}
return failure;
}
// overlapping array region with unknown src/dest offsets: compiled code must include both forward and backward copies
@Args(src=ArraySrc.SMALL, dst=ArrayDst.SRC, extra_args={0,1})
static void m12(int[] src, int[] dest, int srcPos, int destPos) {
System.arraycopy(src, srcPos, dest, destPos, 4);
}
static boolean m12_check(int[] src, int[] dest) {
boolean failure = false;
for (int i = 0; i < 5; i++) {
int j = Math.max(i - 1, 0);
if (dest[i] != src[j]) {
System.out.println("Test m10 failed for " + i + " src[" + j +"]=" + src[j] + ", dest[" + i + "]=" + dest[i]);
failure = true;
}
}
return failure;
}
// Array allocation and copy should optimize out
@Args(src=ArraySrc.SMALL)
static int m13(int[] src) {
int[] dest = new int[5];
System.arraycopy(src, 0, dest, 0, 5);
return dest[0] + dest[1] + dest[2] + dest[3] + dest[4];
}
// Check that copy of length 0 is handled correctly
@Args(src=ArraySrc.ZERO, dst=ArrayDst.NEW)
static void m14(int[] src, int[] dest) {
System.arraycopy(src, 0, dest, 0, 0);
}
// copyOf should compile to loads/stores
@Args(src=ArraySrc.SMALL)
static A[] m15() {
return Arrays.copyOf(small_a_src, 5, A[].class);
}
static Object[] helper16(int i) {
Object[] arr = null;
if ((i%2) == 0) {
arr = small_a_src;
} else {
arr = small_object_src;
}
return arr;
}
// CopyOf may need subtype check
@Args(src=ArraySrc.SMALL, dst=ArrayDst.NONE, extra_args={0})
static A[] m16(A[] unused_src, int i) {
Object[] arr = helper16(i);
return Arrays.copyOf(arr, 5, A[].class);
}
static Object[] helper17_1(int i) {
Object[] arr = null;
if ((i%2) == 0) {
arr = small_a_src;
} else {
arr = small_object_src;
}
return arr;
}
static A[] helper17_2(Object[] arr) {
return Arrays.copyOf(arr, 5, A[].class);
}
// CopyOf may leverage type speculation
@Args(src=ArraySrc.SMALL, dst=ArrayDst.NONE, extra_args={0})
static A[] m17(A[] unused_src, int i) {
Object[] arr = helper17_1(i);
return helper17_2(arr);
}
static Object[] helper18_1(int i) {
Object[] arr = null;
if ((i%2) == 0) {
arr = small_a_src;
} else {
arr = small_object_src;
}
return arr;
}
static Object[] helper18_2(Object[] arr) {
return Arrays.copyOf(arr, 5, Object[].class);
}
// CopyOf should not attempt to use type speculation if it's not needed
@Args(src=ArraySrc.SMALL, dst=ArrayDst.NONE, extra_args={0})
static Object[] m18(A[] unused_src, int i) {
Object[] arr = helper18_1(i);
return helper18_2(arr);
}
static Object[] helper19(int i) {
Object[] arr = null;
if ((i%2) == 0) {
arr = small_a_src;
} else {
arr = small_object_src;
}
return arr;
}
// CopyOf may need subtype check. Test is run to make type check
// fail and cause deoptimization. Next compilation should not
// compile as loads/stores because the first compilation
// deoptimized.
@Args(src=ArraySrc.SMALL, dst=ArrayDst.NONE, extra_args={0})
static A[] m19(A[] unused_src, int i) {
Object[] arr = helper19(i);
return Arrays.copyOf(arr, 5, A[].class);
}
// copyOf for large array should not compile to loads/stores
@Args(src=ArraySrc.LARGE)
static A[] m20() {
return Arrays.copyOf(large_a_src, 10, A[].class);
}
// check zero length copyOf is handled correctly
@Args(src=ArraySrc.ZERO)
static A[] m21() {
return Arrays.copyOf(zero_a_src, 0, A[].class);
}
// Run with srcPos=0 for a 1st compile, then with incorrect value
// of srcPos to cause deoptimization, then with srcPos=0 for a 2nd
// compile. The 2nd compile shouldn't turn arraycopy into
// loads/stores because input arguments are no longer known to be
// valid.
@Args(src=ArraySrc.SMALL, dst=ArrayDst.NEW, extra_args={0})
static void m22(int[] src, int[] dest, int srcPos) {
System.arraycopy(src, srcPos, dest, 0, 5);
}
// copyOfRange should compile to loads/stores
@Args(src=ArraySrc.SMALL)
static A[] m23() {
return Arrays.copyOfRange(small_a_src, 1, 4, A[].class);
}
static boolean m23_check(A[] src, A[] dest) {
boolean failure = false;
for (int i = 0; i < 3; i++) {
if (src[i+1] != dest[i]) {
System.out.println("Test m23 failed for " + i + " src[" + (i+1) +"]=" + dest[i] + ", dest[" + i + "]=" + dest[i]);
failure = true;
}
}
return failure;
}
// array copy should be compiled as loads/stores. Invoke then with
// incompatible array type to verify we don't allow a forbidden
// arraycopy to happen.
@Args(src=ArraySrc.SMALL)
static A[] m24(Object[] src) {
src[0] = src[0]; // force null check
A[] dest = new A[5];
System.arraycopy(src, 0, dest, 0, 5);
return dest;
}
// overlapping array region with unknown src/dest offsets but
// length 1: compiled code doesn't need both forward and backward
// copies
@Args(src=ArraySrc.SMALL, dst=ArrayDst.SRC, extra_args={0,1})
static void m25(int[] src, int[] dest, int srcPos, int destPos) {
System.arraycopy(src, srcPos, dest, destPos, 1);
}
static boolean m25_check(int[] src, int[] dest) {
boolean failure = false;
if (dest[1] != src[0]) {
System.out.println("Test m10 failed for src[0]=" + src[0] + ", dest[1]=" + dest[1]);
return true;
}
return false;
}
final HashMap<String,Method> tests = new HashMap<>();
{
for (Method m : this.getClass().getDeclaredMethods()) {
if (m.getName().matches("m[0-9]+(_check)?")) {
assert(Modifier.isStatic(m.getModifiers())) : m;
tests.put(m.getName(), m);
}
}
}
boolean success = true;
void doTest(String name) throws Exception {
Method m = tests.get(name);
Method m_check = tests.get(name + "_check");
Class[] paramTypes = m.getParameterTypes();
Object[] params = new Object[paramTypes.length];
Class retType = m.getReturnType();
boolean isIntArray = (retType.isPrimitive() && !retType.equals(Void.TYPE)) ||
(retType.equals(Void.TYPE) && paramTypes[0].getComponentType().isPrimitive()) ||
(retType.isArray() && retType.getComponentType().isPrimitive());
Args args = m.getAnnotation(Args.class);
Object src = null;
switch(args.src()) {
case SMALL: {
if (isIntArray) {
src = small_int_src;
} else {
src = small_a_src;
}
break;
}
case LARGE: {
if (isIntArray) {
src = large_int_src;
} else {
src = large_a_src;
}
break;
}
case ZERO: {
assert isIntArray;
if (isIntArray) {
src = zero_int_src;
} else {
src = zero_a_src;
}
break;
}
}
for (int i = 0; i < 20000; i++) {
boolean failure = false;
int p = 0;
if (params.length > 0) {
if (isIntArray) {
params[0] = ((int[])src).clone();
} else {
params[0] = ((A[])src).clone();
}
p++;
}
if (params.length > 1) {
switch(args.dst()) {
case NEW: {
if (isIntArray) {
params[1] = new int[((int[])params[0]).length];
} else {
params[1] = new A[((A[])params[0]).length];
}
p++;
break;
}
case SRC: {
params[1] = params[0];
p++;
break;
}
case NONE: break;
}
}
for (int j = 0; j < args.extra_args().length; j++) {
params[p+j] = args.extra_args()[j];
}
Object res = m.invoke(null, params);
if (retType.isPrimitive() && !retType.equals(Void.TYPE)) {
int s = (int)res;
int sum = 0;
int[] int_res = (int[])src;
for (int j = 0; j < int_res.length; j++) {
sum += int_res[j];
}
failure = (s != sum);
if (failure) {
System.out.println("Test " + name + " failed: result = " + s + " != " + sum);
}
} else {
Object dest = null;
if (!retType.equals(Void.TYPE)) {
dest = res;
} else {
dest = params[1];
}
if (m_check != null) {
failure = (boolean)m_check.invoke(null, new Object[] { src, dest });
} else {
if (isIntArray) {
int[] int_res = (int[])src;
int[] int_dest = (int[])dest;
for (int j = 0; j < int_res.length; j++) {
if (int_res[j] != int_dest[j]) {
System.out.println("Test " + name + " failed for " + j + " src[" + j +"]=" + int_res[j] + ", dest[" + j + "]=" + int_dest[j]);
failure = true;
}
}
} else {
Object[] object_res = (Object[])src;
Object[] object_dest = (Object[])dest;
for (int j = 0; j < object_res.length; j++) {
if (object_res[j] != object_dest[j]) {
System.out.println("Test " + name + " failed for " + j + " src[" + j +"]=" + object_res[j] + ", dest[" + j + "]=" + object_dest[j]);
failure = true;
}
}
}
}
}
if (failure) {
success = false;
break;
}
}
}
public static void main(String[] args) throws Exception {
for (int i = 0; i < small_a_src.length; i++) {
small_a_src[i] = new A();
}
for (int i = 0; i < small_int_src.length; i++) {
small_int_src[i] = i;
}
for (int i = 0; i < large_int_src.length; i++) {
large_int_src[i] = i;
}
for (int i = 0; i < 5; i++) {
small_object_src[i] = new Object();
}
TestArrayCopyAsLoadsStores test = new TestArrayCopyAsLoadsStores();
test.doTest("m1");
test.doTest("m2");
test.doTest("m3");
test.doTest("m4");
test.doTest("m5");
test.doTest("m6");
test.doTest("m7");
test.doTest("m8");
test.doTest("m9");
test.doTest("m10");
test.doTest("m11");
test.doTest("m12");
test.doTest("m13");
test.doTest("m14");
test.doTest("m15");
// make both branches of the If appear taken
for (int i = 0; i < 20000; i++) {
helper16(i);
}
test.doTest("m16");
// load class B so type check in m17 would not be simple comparison
B b = new B();
// make both branches of the If appear taken
for (int i = 0; i < 20000; i++) {
helper17_1(i);
}
test.doTest("m17");
// make both branches of the If appear taken
for (int i = 0; i < 20000; i++) {
helper18_1(i);
}
test.doTest("m18");
// make both branches of the If appear taken
for (int i = 0; i < 20000; i++) {
helper19(i);
}
// Compile
for (int i = 0; i < 20000; i++) {
m19(null, 0);
}
// force deopt
boolean m19_exception = false;
for (int i = 0; i < 10; i++) {
try {
m19(null, 1);
} catch(ArrayStoreException ase) {
m19_exception = true;
}
}
if (!m19_exception) {
System.out.println("Test m19: exception wasn't thrown");
test.success = false;
}
test.doTest("m19");
test.doTest("m20");
test.doTest("m21");
// Compile
int[] dst = new int[small_int_src.length];
for (int i = 0; i < 20000; i++) {
m22(small_int_src, dst, 0);
}
// force deopt
for (int i = 0; i < 10; i++) {
try {
m22(small_int_src, dst, 5);
} catch(ArrayIndexOutOfBoundsException aioobe) {}
}
test.doTest("m22");
test.doTest("m23");
test.doTest("m24");
boolean m24_exception = false;
try {
m24(small_object_src);
} catch(ArrayStoreException ase) {
m24_exception = true;
}
if (!m24_exception) {
System.out.println("Test m24: exception wasn't thrown");
test.success = false;
}
test.doTest("m25");
if (!test.success) {
throw new RuntimeException("some tests failed");
}
}
}