jdk/test/java/lang/invoke/RicochetTest.java
changeset 9646 5ebbe5ab084f
child 9781 ce852878da20
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/lang/invoke/RicochetTest.java	Thu May 12 19:27:49 2011 -0700
@@ -0,0 +1,582 @@
+/*
+ * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * 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.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * 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.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @summary unit tests for recursive method handles
+ * @run junit/othervm -DRicochetTest.MAX_ARITY=255 test.java.lang.invoke.RicochetTest
+ */
+
+package test.java.lang.invoke;
+
+import java.lang.invoke.*;
+import java.util.*;
+import org.junit.*;
+import static java.lang.invoke.MethodType.*;
+import static java.lang.invoke.MethodHandles.*;
+import static org.junit.Assert.*;
+import static org.junit.Assume.*;
+
+
+/**
+ *
+ * @author jrose
+ */
+public class RicochetTest {
+    private static final Class CLASS = RicochetTest.class;
+    private static final int MAX_ARITY = Integer.getInteger(CLASS.getSimpleName()+".MAX_ARITY", 40);
+
+    public static void main(String... av) throws Throwable {
+        RicochetTest test = new RicochetTest();
+        if (av.length > 0)  test.testOnly = Arrays.asList(av).toString();
+        if (REPEAT == 1 || test.testOnly != null) {
+            test.testAll();
+            if (test.testOnlyTests == null)  throw new RuntimeException("no matching test: "+test.testOnly);
+        } else if (REPEAT == 0) {
+            org.junit.runner.JUnitCore.runClasses(RicochetTest.class);
+        } else {
+            verbose(1, "REPEAT="+REPEAT);
+            for (int i = 0; i < REPEAT; i++) {
+                test.testRepetition = (i+1);
+                verbose(0, "[#"+test.testRepetition+"]");
+                test.testAll();
+            }
+        }
+    }
+    int testRepetition;
+
+    public void testAll() throws Throwable {
+        testNull();
+        testBoxInteger();
+        testFilterReturnValue();
+        testFilterObject();
+        testBoxLong();
+        testFilterInteger();
+        testIntSpreads();
+        testByteSpreads();
+        testLongSpreads();
+        testIntCollects();
+        testReturns();
+    }
+
+    @Test
+    public void testNull() throws Throwable {
+        if (testRepetition > (1+REPEAT/100))  return;  // trivial test
+        if (!startTest("testNull"))  return;
+        assertEquals(opI(37), opI.invokeWithArguments(37));
+        assertEqualFunction(opI, opI);
+    }
+
+    @Test
+    public void testBoxInteger() throws Throwable {
+        if (!startTest("testBoxInteger"))  return;
+        assertEqualFunction(opI, opI.asType(opL_I.type()).asType(opI.type()));
+    }
+
+    @Test
+    public void testFilterReturnValue() throws Throwable {
+        if (!startTest("testFilterReturnValue"))  return;
+        int[] ints = { 12, 23, 34, 45, 56, 67, 78, 89 };
+        Object res = list8ints.invokeExact(ints[0], ints[1], ints[2], ints[3], ints[4], ints[5], ints[6], ints[7]);
+        assertEquals(Arrays.toString(ints), res.toString());
+        MethodHandle idreturn = filterReturnValue(list8ints, identity(Object.class));
+        res = idreturn.invokeExact(ints[0], ints[1], ints[2], ints[3], ints[4], ints[5], ints[6], ints[7]);
+        assertEquals(Arrays.toString(ints), res.toString());
+        MethodHandle add0 = addL.bindTo(0);
+        assertEqualFunction(filterReturnValue(opL2, add0), opL2);
+    }
+
+    @Test
+    public void testFilterObject() throws Throwable {
+        if (!startTest("testFilterObject"))  return;
+        MethodHandle add0 = addL.bindTo(0);
+        assertEqualFunction(sequence(opL2, add0), opL2);
+        int bump13 = -13;  // value near 20 works as long as test values are near [-80..80]
+        MethodHandle add13   = addL.bindTo(bump13);
+        MethodHandle add13_0 = addL.bindTo(opI2(bump13, 0));
+        MethodHandle add13_1 = addL.bindTo(opI2(0, bump13));
+        assertEqualFunction(sequence(opL2, add13_0),
+                            filterArguments(opL2, 0, add13));
+        assertEqualFunction(sequence(opL2, add13_1),
+                            filterArguments(opL2, 1, add13));
+        System.out.println("[testFilterObject done]");
+    }
+
+    @Test
+    public void testBoxLong() throws Throwable {
+        if (!startTest("testBoxLong"))  return;
+        assertEqualFunction(opJ, opJ.asType(opL_J.type()).asType(opJ.type()));
+    }
+
+    @Test
+    public void testFilterInteger() throws Throwable {
+        if (!startTest("testFilterInteger"))  return;
+        assertEqualFunction(opI, sequence(convI_L, opL_I));
+    }
+
+    @Test
+    public void testIntSpreads() throws Throwable {
+        if (!startTest("testIntSpreads"))  return;
+        MethodHandle id = identity(int[].class);
+        final int MAX = MAX_ARITY-2;  // 253+1 would cause parameter overflow with 'this' added
+        for (int nargs = 0; nargs <= MAX; nargs++) {
+            if (nargs > 30 && nargs < MAX-20)  nargs += 10;
+            int[] args = new int[nargs];
+            for (int j = 0; j < args.length; j++)  args[j] = (int)(j + 11);
+            //System.out.println("testIntSpreads "+Arrays.toString(args));
+            int[] args1 = (int[]) id.invokeExact(args);
+            assertArrayEquals(args, args1);
+            MethodHandle coll = id.asCollector(int[].class, nargs);
+            int[] args2 = args;
+            switch (nargs) {
+                case 0:  args2 = (int[]) coll.invokeExact(); break;
+                case 1:  args2 = (int[]) coll.invokeExact(args[0]); break;
+                case 2:  args2 = (int[]) coll.invokeExact(args[0], args[1]); break;
+                case 3:  args2 = (int[]) coll.invokeExact(args[0], args[1], args[2]); break;
+                case 4:  args2 = (int[]) coll.invokeExact(args[0], args[1], args[2], args[3]); break;
+                case 5:  args2 = (int[]) coll.invokeExact(args[0], args[1], args[2], args[3], args[4]); break;
+            }
+            assertArrayEquals(args, args2);
+            MethodHandle mh = coll.asSpreader(int[].class, nargs);
+            int[] args3 = (int[]) mh.invokeExact(args);
+            assertArrayEquals(args, args3);
+        }
+    }
+
+    @Test
+    public void testByteSpreads() throws Throwable {
+        if (!startTest("testByteSpreads"))  return;
+        MethodHandle id = identity(byte[].class);
+        final int MAX = MAX_ARITY-2;  // 253+1 would cause parameter overflow with 'this' added
+        for (int nargs = 0; nargs <= MAX; nargs++) {
+            if (nargs > 30 && nargs < MAX-20)  nargs += 10;
+            byte[] args = new byte[nargs];
+            for (int j = 0; j < args.length; j++)  args[j] = (byte)(j + 11);
+            //System.out.println("testByteSpreads "+Arrays.toString(args));
+            byte[] args1 = (byte[]) id.invokeExact(args);
+            assertArrayEquals(args, args1);
+            MethodHandle coll = id.asCollector(byte[].class, nargs);
+            byte[] args2 = args;
+            switch (nargs) {
+                case 0:  args2 = (byte[]) coll.invokeExact(); break;
+                case 1:  args2 = (byte[]) coll.invokeExact(args[0]); break;
+                case 2:  args2 = (byte[]) coll.invokeExact(args[0], args[1]); break;
+                case 3:  args2 = (byte[]) coll.invokeExact(args[0], args[1], args[2]); break;
+                case 4:  args2 = (byte[]) coll.invokeExact(args[0], args[1], args[2], args[3]); break;
+                case 5:  args2 = (byte[]) coll.invokeExact(args[0], args[1], args[2], args[3], args[4]); break;
+            }
+            assertArrayEquals(args, args2);
+            MethodHandle mh = coll.asSpreader(byte[].class, nargs);
+            byte[] args3 = (byte[]) mh.invokeExact(args);
+            assertArrayEquals(args, args3);
+        }
+    }
+
+    @Test
+    public void testLongSpreads() throws Throwable {
+        if (!startTest("testLongSpreads"))  return;
+        MethodHandle id = identity(long[].class);
+        final int MAX = (MAX_ARITY - 2) / 2;  // 253/2+1 would cause parameter overflow with 'this' added
+        for (int nargs = 0; nargs <= MAX; nargs++) {
+            if (nargs > 30 && nargs < MAX-20)  nargs += 10;
+            long[] args = new long[nargs];
+            for (int j = 0; j < args.length; j++)  args[j] = (long)(j + 11);
+            //System.out.println("testLongSpreads "+Arrays.toString(args));
+            long[] args1 = (long[]) id.invokeExact(args);
+            assertArrayEquals(args, args1);
+            MethodHandle coll = id.asCollector(long[].class, nargs);
+            long[] args2 = args;
+            switch (nargs) {
+                case 0:  args2 = (long[]) coll.invokeExact(); break;
+                case 1:  args2 = (long[]) coll.invokeExact(args[0]); break;
+                case 2:  args2 = (long[]) coll.invokeExact(args[0], args[1]); break;
+                case 3:  args2 = (long[]) coll.invokeExact(args[0], args[1], args[2]); break;
+                case 4:  args2 = (long[]) coll.invokeExact(args[0], args[1], args[2], args[3]); break;
+                case 5:  args2 = (long[]) coll.invokeExact(args[0], args[1], args[2], args[3], args[4]); break;
+            }
+            assertArrayEquals(args, args2);
+            MethodHandle mh = coll.asSpreader(long[].class, nargs);
+            long[] args3 = (long[]) mh.invokeExact(args);
+            assertArrayEquals(args, args3);
+        }
+    }
+
+    @Test
+    public void testIntCollects() throws Throwable {
+        if (!startTest("testIntCollects"))  return;
+        for (MethodHandle lister : INT_LISTERS) {
+            int outputs = lister.type().parameterCount();
+            for (int collects = 0; collects <= Math.min(outputs, INT_COLLECTORS.length-1); collects++) {
+                int inputs = outputs - 1 + collects;
+                if (inputs < 0)  continue;
+                for (int pos = 0; pos + collects <= inputs; pos++) {
+                    MethodHandle collector = INT_COLLECTORS[collects];
+                    int[] args = new int[inputs];
+                    int ap = 0, arg = 31;
+                    for (int i = 0; i < pos; i++)
+                        args[ap++] = arg++ + 0;
+                    for (int i = 0; i < collects; i++)
+                        args[ap++] = arg++ + 10;
+                    while (ap < args.length)
+                        args[ap++] = arg++ + 20;
+                    // calculate piecemeal:
+                    //System.out.println("testIntCollects "+Arrays.asList(lister, pos, collector)+" on "+Arrays.toString(args));
+                    int[] collargs = Arrays.copyOfRange(args, pos, pos+collects);
+                    int coll = (int) collector.asSpreader(int[].class, collargs.length).invokeExact(collargs);
+                    int[] listargs = Arrays.copyOfRange(args, 0, outputs);
+                    System.arraycopy(args, pos+collects, listargs, pos+1, outputs - (pos+1));
+                    listargs[pos] = coll;
+                    //System.out.println("  coll="+coll+" listargs="+Arrays.toString(listargs));
+                    Object expect = lister.asSpreader(int[].class, listargs.length).invokeExact(listargs);
+                    //System.out.println("  expect="+expect);
+
+                    // now use the combined MH, and test the output:
+                    MethodHandle mh = collectArguments(lister, pos, INT_COLLECTORS[collects]);
+                    if (mh == null)  continue;  // no infix collection, yet
+                    assert(mh.type().parameterCount() == inputs);
+                    Object observe = mh.asSpreader(int[].class, args.length).invokeExact(args);
+                    assertEquals(expect, observe);
+                }
+            }
+        }
+    }
+
+    private static MethodHandle collectArguments(MethodHandle lister, int pos, MethodHandle collector) {
+        int collects = collector.type().parameterCount();
+        int outputs = lister.type().parameterCount();
+        if (pos == outputs - 1)
+            return MethodHandles.filterArguments(lister, pos,
+                        collector.asSpreader(int[].class, collects))
+                            .asCollector(int[].class, collects);
+        //return MethodHandles.collectArguments(lister, pos, collector); //no such animal
+        return null;
+    }
+
+    private static final Class<?>[] RETURN_TYPES = {
+        Object.class, String.class, Integer.class,
+        int.class, long.class,
+        boolean.class, byte.class, char.class, short.class,
+        float.class, double.class,
+        void.class,
+    };
+
+    @Test
+    public void testReturns() throws Throwable {
+        if (!startTest("testReturns"))  return;
+        // fault injection:
+        int faultCount = 0;  // total of 1296 tests
+        faultCount = Integer.getInteger("testReturns.faultCount", 0);
+        for (Class<?> ret : RETURN_TYPES) {
+            // make a complicated identity function and pass something through it
+            System.out.println(ret.getSimpleName());
+            Class<?> vret = (ret == void.class) ? Void.class : ret;
+            MethodHandle id = // (vret)->ret
+                identity(vret).asType(methodType(ret, vret));
+            final int LENGTH = 4;
+            int[] index = {0};
+            Object vals = java.lang.reflect.Array.newInstance(vret, LENGTH);
+            MethodHandle indexGetter =  //()->int
+                insertArguments(arrayElementGetter(index.getClass()), 0, index, 0);
+            MethodHandle valSelector =  // (int)->vret
+                arrayElementGetter(vals.getClass()).bindTo(vals);
+            MethodHandle valGetter =  // ()->vret
+                foldArguments(valSelector, indexGetter);
+            if (ret != void.class) {
+                for (int i = 0; i < LENGTH; i++) {
+                    Object val = (i + 50);
+                    if (ret == boolean.class)  val = (i % 3 == 0);
+                    if (ret == String.class)   val = "#"+i;
+                    if (ret == char.class)     val = (char)('a'+i);
+                    if (ret == byte.class)     val = (byte)~i;
+                    if (ret == short.class)    val = (short)(1<<i);
+                    java.lang.reflect.Array.set(vals, i, val);
+                }
+            }
+            for (int i = 0; i < LENGTH; i++) {
+                Object val = java.lang.reflect.Array.get(vals, i);
+                System.out.println(i+" => "+val);
+                index[0] = i;
+                if (--faultCount == 0)  index[0] ^= 1;
+                Object x = valGetter.invokeWithArguments();
+                assertEquals(val, x);
+                // make a return-filter call:  x = id(valGetter())
+                if (--faultCount == 0)  index[0] ^= 1;
+                x = filterReturnValue(valGetter, id).invokeWithArguments();
+                assertEquals(val, x);
+                // make a filter call:  x = id(*,valGetter(),*)
+                for (int len = 1; len <= 4; len++) {
+                    for (int pos = 0; pos < len; pos++) {
+                        MethodHandle proj = id;  // lambda(..., vret x,...){x}
+                        for (int j = 0; j < len; j++) {
+                            if (j == pos)  continue;
+                            proj = dropArguments(proj, j, Object.class);
+                        }
+                        assert(proj.type().parameterCount() == len);
+                        // proj: (Object*, pos: vret, Object*)->ret
+                        assertEquals(vret, proj.type().parameterType(pos));
+                        MethodHandle vgFilter = dropArguments(valGetter, 0, Object.class);
+                        if (--faultCount == 0)  index[0] ^= 1;
+                        x = filterArguments(proj, pos, vgFilter).invokeWithArguments(new Object[len]);
+                        assertEquals(val, x);
+                    }
+                }
+                // make a fold call:
+                for (int len = 0; len <= 4; len++) {
+                    for (int fold = 0; fold <= len; fold++) {
+                        MethodHandle proj = id;  // lambda(ret x, ...){x}
+                        if (ret == void.class)  proj = constant(Object.class, null);
+                        int arg0 = (ret == void.class ? 0 : 1);
+                        for (int j = 0; j < len; j++) {
+                            proj = dropArguments(proj, arg0, Object.class);
+                        }
+                        assert(proj.type().parameterCount() == arg0 + len);
+                        // proj: (Object*, pos: vret, Object*)->ret
+                        if (arg0 != 0)  assertEquals(vret, proj.type().parameterType(0));
+                        MethodHandle vgFilter = valGetter.asType(methodType(ret));
+                        for (int j = 0; j < fold; j++) {
+                            vgFilter = dropArguments(vgFilter, j, Object.class);
+                        }
+                        x = foldArguments(proj, vgFilter).invokeWithArguments(new Object[len]);
+                        if (--faultCount == 0)  index[0] ^= 1;
+                        assertEquals(val, x);
+                    }
+                }
+            }
+        }
+        //System.out.println("faultCount="+faultCount);
+    }
+
+    private static MethodHandle sequence(MethodHandle mh1, MethodHandle... mhs) {
+        MethodHandle res = mh1;
+        for (MethodHandle mh2 : mhs)
+            res = filterReturnValue(res, mh2);
+        return res;
+    }
+    private static void assertEqualFunction(MethodHandle x, MethodHandle y) throws Throwable {
+        assertEquals(x.type(), y.type()); //??
+        MethodType t = x.type();
+        if (t.parameterCount() == 0) {
+            assertEqualFunctionAt(null, x, y);
+            return;
+        }
+        Class<?> ptype = t.parameterType(0);
+        if (ptype == long.class || ptype == Long.class) {
+            for (long i = -10; i <= 10; i++) {
+                assertEqualFunctionAt(i, x, y);
+            }
+        } else {
+            for (int i = -10; i <= 10; i++) {
+                assertEqualFunctionAt(i, x, y);
+            }
+        }
+    }
+    private static void assertEqualFunctionAt(Object v, MethodHandle x, MethodHandle y) throws Throwable {
+        Object[] args = new Object[x.type().parameterCount()];
+        Arrays.fill(args, v);
+        Object xval = invokeWithCatch(x, args);
+        Object yval = invokeWithCatch(y, args);
+        String msg = "ok";
+        if (!Objects.equals(xval, yval)) {
+            msg = ("applying "+x+" & "+y+" to "+v);
+        }
+        assertEquals(msg, xval, yval);
+    }
+    private static Object invokeWithCatch(MethodHandle mh, Object... args) throws Throwable {
+        try {
+            return mh.invokeWithArguments(args);
+        } catch (Throwable ex) {
+            System.out.println("threw: "+mh+Arrays.asList(args));
+            ex.printStackTrace();
+            return ex;
+        }
+    }
+
+    private static final Lookup LOOKUP = lookup();
+    private static MethodHandle findStatic(String name,
+                                           Class<?> rtype,
+                                           Class<?>... ptypes) {
+        try {
+            return LOOKUP.findStatic(LOOKUP.lookupClass(), name, methodType(rtype, ptypes));
+        } catch (ReflectiveOperationException ex) {
+            throw new RuntimeException(ex);
+        }
+    }
+    private static MethodHandle findStatic(String name,
+                                           Class<?> rtype,
+                                           List<?> ptypes) {
+        return findStatic(name, rtype, ptypes.toArray(new Class<?>[ptypes.size()]));
+    }
+    static int getProperty(String name, int dflt) {
+        String qual = LOOKUP.lookupClass().getName();
+        String prop = System.getProperty(qual+"."+name);
+        if (prop == null)  prop = System.getProperty(name);
+        if (prop == null)  return dflt;
+        return Integer.parseInt(prop);
+    }
+
+    private static int opI(int... xs) {
+        stress();
+        int base = 100;
+        int z = 0;
+        for (int x : xs) {
+            z = (z * base) + (x % base);
+        }
+        verbose("opI", xs.length, xs, z);
+        return z;
+    }
+    private static int opI2(int x, int y) { return opI(x, y); }  // x*100 + y%100
+    private static int opI3(int x, int y, int z) { return opI(x, y, z); }
+    private static int opI4(int w, int x, int y, int z) { return opI(w, x, y, z); }
+    private static int opI(int x) { return opI2(x, 37); }
+    private static Object opI_L(int x) { return (Object) opI(x); }
+    private static long opJ3(long x, long y, long z) { return (long) opI3((int)x, (int)y, (int)z); }
+    private static long opJ2(long x, long y) { return (long) opI2((int)x, (int)y); }
+    private static long opJ(long x) { return (long) opI((int)x); }
+    private static Object opL2(Object x, Object y) { return (Object) opI2((int)x, (int)y); }
+    private static Object opL(Object x) { return (Object) opI((int)x); }
+    private static int opL2_I(Object x, Object y) { return (int) opI2((int)x, (int)y); }
+    private static int opL_I(Object x) { return (int) opI((int)x); }
+    private static long opL_J(Object x) { return (long) opI((int)x); }
+    private static final MethodHandle opI, opI2, opI3, opI4, opI_L, opJ, opJ2, opJ3, opL2, opL, opL2_I, opL_I, opL_J;
+    static {
+        opI4 = findStatic("opI4", int.class, int.class, int.class, int.class, int.class);
+        opI3 = findStatic("opI3", int.class, int.class, int.class, int.class);
+        opI2 = findStatic("opI2", int.class, int.class, int.class);
+        opI = findStatic("opI", int.class, int.class);
+        opI_L = findStatic("opI_L", Object.class, int.class);
+        opJ = findStatic("opJ", long.class, long.class);
+        opJ2 = findStatic("opJ2", long.class, long.class, long.class);
+        opJ3 = findStatic("opJ3", long.class, long.class, long.class, long.class);
+        opL2 = findStatic("opL2", Object.class, Object.class, Object.class);
+        opL = findStatic("opL", Object.class, Object.class);
+        opL2_I = findStatic("opL2_I", int.class, Object.class, Object.class);
+        opL_I = findStatic("opL_I", int.class, Object.class);
+        opL_J = findStatic("opL_J", long.class, Object.class);
+    }
+    private static final MethodHandle[] INT_COLLECTORS = {
+        constant(int.class, 42), opI, opI2, opI3, opI4
+    };
+    private static final MethodHandle[] LONG_COLLECTORS = {
+        constant(long.class, 42), opJ, opJ2, opJ3
+    };
+
+    private static int addI(int x, int y) { stress(); return x+y; }
+    private static Object addL(Object x, Object y) { return addI((int)x, (int)y); }
+    private static final MethodHandle addI, addL;
+    static {
+        addI = findStatic("addI", int.class, int.class, int.class);
+        addL = findStatic("addL", Object.class, Object.class, Object.class);
+    }
+
+    private static Object list8ints(int a, int b, int c, int d, int e, int f, int g, int h) {
+        return Arrays.asList(a, b, c, d, e, f, g, h);
+    }
+    private static Object list8longs(long a, long b, long c, long d, long e, long f, long g, long h) {
+        return Arrays.asList(a, b, c, d, e, f, g, h);
+    }
+    private static final MethodHandle list8ints = findStatic("list8ints", Object.class,
+                                                             Collections.nCopies(8, int.class));
+    private static final MethodHandle list8longs = findStatic("list8longs", Object.class,
+                                                              Collections.nCopies(8, long.class));
+    private static final MethodHandle[] INT_LISTERS, LONG_LISTERS;
+    static {
+        int listerCount = list8ints.type().parameterCount() + 1;
+        INT_LISTERS  = new MethodHandle[listerCount];
+        LONG_LISTERS = new MethodHandle[listerCount];
+        MethodHandle lister = list8ints;
+        MethodHandle llister = list8longs;
+        for (int i = listerCount - 1; ; i--) {
+            INT_LISTERS[i] = lister;
+            LONG_LISTERS[i] = llister;
+            if (i == 0)  break;
+            lister  = insertArguments(lister,  i-1, (int)0);
+            llister = insertArguments(llister, i-1, (long)0);
+        }
+    }
+
+    private static Object  convI_L(int     x) { stress(); return (Object)  x; }
+    private static int     convL_I(Object  x) { stress(); return (int)     x; }
+    private static Object  convJ_L(long    x) { stress(); return (Object)  x; }
+    private static long    convL_J(Object  x) { stress(); return (long)    x; }
+    private static int     convJ_I(long    x) { stress(); return (int)     x; }
+    private static long    convI_J(int     x) { stress(); return (long)    x; }
+    private static final MethodHandle convI_L, convL_I, convJ_L, convL_J, convJ_I, convI_J;
+    static {
+        convI_L = findStatic("convI_L", Object.class, int.class);
+        convL_I = findStatic("convL_I", int.class, Object.class);
+        convJ_L = findStatic("convJ_L", Object.class, long.class);
+        convL_J = findStatic("convL_J", long.class, Object.class);
+        convJ_I = findStatic("convJ_I", int.class, long.class);
+        convI_J = findStatic("convI_J", long.class, int.class);
+    }
+
+    // stress modes:
+    private static final int REPEAT = getProperty("REPEAT", 0);
+    private static final int STRESS = getProperty("STRESS", 0);
+    private static /*v*/ int STRESS_COUNT;
+    private static final Object[] SINK = new Object[4];
+    private static void stress() {
+        if (STRESS <= 0) return;
+        int count = STRESS + (STRESS_COUNT++ & 0x1);  // non-constant value
+        for (int i = 0; i < count; i++) {
+            SINK[i % SINK.length] = new Object[STRESS + i % (SINK.length + 1)];
+        }
+    }
+
+    // verbosity:
+    private static final int VERBOSITY = getProperty("VERBOSITY", 0) + (REPEAT == 0 ? 0 : -1);
+    private static void verbose(Object a, Object b, Object c, Object d) {
+        if (VERBOSITY <= 0)  return;
+        verbose(1, a, b, c, d);
+    }
+    private static void verbose(Object a, Object b, Object c) {
+        if (VERBOSITY <= 0)  return;
+        verbose(1, a, b, c);
+    }
+    private static void verbose(int level, Object a, Object... bcd) {
+        if (level > VERBOSITY)  return;
+        String m = a.toString();
+        if (bcd != null && bcd.length > 0) {
+            List<Object> l = new ArrayList<>(bcd.length);
+            for (Object x : bcd) {
+                if (x instanceof Object[])  x = Arrays.asList((Object[])x);
+                if (x instanceof int[])     x = Arrays.toString((int[])x);
+                if (x instanceof long[])    x = Arrays.toString((long[])x);
+                l.add(x);
+            }
+            m = m+Arrays.asList(bcd);
+        }
+        System.out.println(m);
+    }
+    String testOnly;
+    String testOnlyTests;
+    private boolean startTest(String name) {
+        if (testOnly != null && !testOnly.contains(name))
+            return false;
+        verbose(0, "["+name+"]");
+        testOnlyTests = (testOnlyTests == null) ? name : testOnlyTests+" "+name;
+        return true;
+    }
+
+}