1 /*
2 * Copyright (c) 2021, 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 /*
25 * @test
26 * @summary Test ObjectMethods::bootstrap call via condy
27 * @modules java.base/jdk.internal.value
28 * java.base/jdk.internal.org.objectweb.asm
29 * @enablePreview
30 * @run testng/othervm ObjectMethodsViaCondy
31 */
32
33 import java.io.IOException;
34 import java.io.OutputStream;
35 import java.io.UncheckedIOException;
36 import java.lang.invoke.MethodHandle;
37 import java.lang.invoke.MethodHandles;
38 import java.lang.invoke.MethodHandles.Lookup.ClassOption;
39 import java.lang.invoke.MethodType;
40 import java.lang.invoke.TypeDescriptor;
41 import java.nio.file.Files;
42 import java.nio.file.Path;
43 import java.nio.file.Paths;
44 import java.util.Arrays;
45 import java.util.stream.Stream;
46
47 import jdk.internal.org.objectweb.asm.ClassWriter;
48 import jdk.internal.org.objectweb.asm.ConstantDynamic;
49 import jdk.internal.org.objectweb.asm.Handle;
50 import jdk.internal.org.objectweb.asm.MethodVisitor;
51 import jdk.internal.org.objectweb.asm.Type;
52 import org.testng.annotations.Test;
53 import static java.lang.invoke.MethodType.methodType;
54 import static jdk.internal.org.objectweb.asm.Opcodes.ACC_FINAL;
55 import static jdk.internal.org.objectweb.asm.Opcodes.ACC_IDENTITY;
56 import static jdk.internal.org.objectweb.asm.Opcodes.ACC_PUBLIC;
57 import static jdk.internal.org.objectweb.asm.Opcodes.ACC_STATIC;
58 import static jdk.internal.org.objectweb.asm.Opcodes.ALOAD;
59 import static jdk.internal.org.objectweb.asm.Opcodes.ARETURN;
60 import static jdk.internal.org.objectweb.asm.Opcodes.H_GETFIELD;
61 import static jdk.internal.org.objectweb.asm.Opcodes.H_INVOKESTATIC;
62 import static jdk.internal.org.objectweb.asm.Opcodes.INVOKESPECIAL;
63 import static jdk.internal.org.objectweb.asm.Opcodes.RETURN;
64 import static jdk.internal.org.objectweb.asm.Opcodes.V19;
65 import static org.testng.Assert.assertEquals;
66 import static org.testng.Assert.assertTrue;
67 import static org.testng.Assert.assertFalse;
68
69 public class ObjectMethodsViaCondy {
70 public static value record ValueRecord(int i, String name) {
71 static final MethodHandles.Lookup LOOKUP = MethodHandles.lookup();
72 static final MethodType TO_STRING_DESC = methodType(String.class, ValueRecord.class);
73 static final Handle[] ACCESSORS = accessors();
74 static final String NAME_LIST = "i;name";
75 private static Handle[] accessors() {
76 try {
77 return new Handle[]{
78 new Handle(H_GETFIELD, Type.getInternalName(ValueRecord.class), "i", "I", false),
79 new Handle(H_GETFIELD, Type.getInternalName(ValueRecord.class), "name", String.class.descriptorString(), false)
80 };
81 } catch (Exception e) {
82 throw new AssertionError(e);
83 }
84 }
85
86 /**
87 * Returns the method handle for the given method for this ValueRecord class.
88 * This method defines a hidden class to invoke the ObjectMethods::bootstrap method
89 * via condy.
90 *
91 * @param methodName the name of the method to generate, which must be one of
92 * {@code "equals"}, {@code "hashCode"}, or {@code "toString"}
93 */
94 static MethodHandle makeBootstrapMethod(String methodName) throws Throwable {
95 ClassFileBuilder builder = new ClassFileBuilder("Test-" + methodName);
96 builder.bootstrapMethod(methodName, TO_STRING_DESC, ValueRecord.class, NAME_LIST, ACCESSORS);
97 byte[] bytes = builder.build();
98 MethodHandles.Lookup lookup = LOOKUP.defineHiddenClass(bytes, true, ClassOption.NESTMATE);
99 MethodType mtype = MethodType.methodType(Object.class);
100 MethodHandle mh = lookup.findStatic(lookup.lookupClass(), "bootstrap", mtype);
101 return (MethodHandle) mh.invoke();
102 }
103 }
104
105 @Test
106 public void testToString() throws Throwable {
107 MethodHandle handle = ValueRecord.makeBootstrapMethod("toString");
108 assertEquals((String)handle.invokeExact(new ValueRecord(10, "ten")), "ValueRecord[i=10, name=ten]");
109 assertEquals((String)handle.invokeExact(new ValueRecord(40, "forty")), "ValueRecord[i=40, name=forty]");
110 }
111
112 @Test
113 public void testToEquals() throws Throwable {
114 MethodHandle handle = ValueRecord.makeBootstrapMethod("equals");
115 assertTrue((boolean)handle.invoke(new ValueRecord(10, "ten"), new ValueRecord(10, "ten")));
116 assertFalse((boolean)handle.invoke(new ValueRecord(11, "eleven"), new ValueRecord(10, "ten")));
117 }
118
119 static class ClassFileBuilder {
120 private static final String OBJECT_CLS = "java/lang/Object";
121 private static final String OBJ_METHODS_CLS = "java/lang/runtime/ObjectMethods";
122 private static final String BSM_DESCR =
123 MethodType.methodType(Object.class, MethodHandles.Lookup.class, String.class,
124 TypeDescriptor.class, Class.class, String.class, MethodHandle[].class)
125 .descriptorString();
126 private final ClassWriter cw;
127 private final String classname;
128
129 /**
130 * A builder to generate a class file to access class data
131 *
132 * @param classname
133 */
134 ClassFileBuilder(String classname) {
135 this.classname = classname;
136 this.cw = new ClassWriter(ClassWriter.COMPUTE_FRAMES);
137 cw.visit(V19, ACC_FINAL | ACC_IDENTITY, classname, null, OBJECT_CLS, null);
138 MethodVisitor mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
139 mv.visitCode();
140 mv.visitVarInsn(ALOAD, 0);
141 mv.visitMethodInsn(INVOKESPECIAL, OBJECT_CLS, "<init>", "()V", false);
142 mv.visitInsn(RETURN);
143 mv.visitMaxs(0, 0);
144 mv.visitEnd();
145 }
146
147 byte[] build() {
148 cw.visitEnd();
149 byte[] bytes = cw.toByteArray();
150 Path p = Paths.get(classname + ".class");
151 try (OutputStream os = Files.newOutputStream(p)) {
152 os.write(bytes);
153 } catch (IOException e) {
154 throw new UncheckedIOException(e);
155 }
156 return bytes;
157 }
158
159 /*
160 * Generate the bootstrap method that invokes ObjectMethods::bootstrap via condy
161 */
162 void bootstrapMethod(String name, TypeDescriptor descriptor, Class<?> recordClass, String names, Handle[] getters) {
163 MethodType mtype = MethodType.methodType(Object.class);
164 MethodVisitor mv = cw.visitMethod(ACC_PUBLIC|ACC_STATIC,
165 "bootstrap", mtype.descriptorString(), null, null);
166 mv.visitCode();
167 Handle bsm = new Handle(H_INVOKESTATIC, OBJ_METHODS_CLS, "bootstrap",
168 BSM_DESCR, false);
169 Object[] args = Stream.concat(Stream.of(Type.getType(recordClass), names), Arrays.stream(getters)).toArray();
170 ConstantDynamic dynamic = new ConstantDynamic(name, MethodHandle.class.descriptorString(), bsm, args);
171 mv.visitLdcInsn(dynamic);
172 mv.visitInsn(ARETURN);
173 mv.visitMaxs(0, 0);
174 mv.visitEnd();
175 }
176 }
177 }