1 /* 2 * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 import org.testng.Assert; 25 import org.testng.annotations.Test; 26 27 import java.lang.classfile.ClassFile; 28 import java.lang.classfile.Label; 29 import java.lang.constant.ClassDesc; 30 import java.lang.constant.ConstantDescs; 31 import java.lang.constant.MethodTypeDesc; 32 import java.lang.reflect.code.op.CoreOp; 33 import java.lang.reflect.code.bytecode.BytecodeLift; 34 import java.lang.reflect.code.interpreter.Interpreter; 35 36 /* 37 * @test 38 * @enablePreview 39 * @run testng TestLiftCustomBytecode 40 */ 41 42 public class TestLiftCustomBytecode { 43 44 @Test 45 public void testBackJumps() throws Throwable { 46 CoreOp.FuncOp f = getFuncOp(ClassFile.of().build(ClassDesc.of("BackJumps"), clb -> 47 clb.withMethodBody("backJumps", MethodTypeDesc.of(ConstantDescs.CD_int, ConstantDescs.CD_int), ClassFile.ACC_STATIC, cob -> { 48 Label l1 = cob.newLabel(); 49 Label l2 = cob.newLabel(); 50 Label l3 = cob.newLabel(); 51 Label l4 = cob.newLabel(); 52 // Code wrapped in back jumps requires multiple passes and block skipping 53 cob.goto_(l1) 54 .labelBinding(l2) 55 .goto_(l3) 56 .labelBinding(l4) 57 .iload(0) 58 .ireturn() 59 .labelBinding(l1) 60 .goto_(l2) 61 .labelBinding(l3) 62 .goto_(l4); 63 })), "backJumps"); 64 65 Assert.assertEquals((int) Interpreter.invoke(f, 42), 42); 66 } 67 68 static CoreOp.FuncOp getFuncOp(byte[] classdata, String method) { 69 CoreOp.FuncOp flift = BytecodeLift.lift(classdata, method); 70 flift.writeTo(System.out); 71 return flift; 72 } 73 }