1 /*
2 * Copyright (c) 2016, 2019, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package jdk.jfr.internal;
27
28 import java.util.List;
29 import java.util.concurrent.atomic.AtomicLong;
30
31 import jdk.internal.org.objectweb.asm.AnnotationVisitor;
32 import jdk.internal.org.objectweb.asm.ClassWriter;
33 import jdk.internal.org.objectweb.asm.Label;
34 import jdk.internal.org.objectweb.asm.MethodVisitor;
35 import jdk.internal.org.objectweb.asm.Opcodes;
36 import jdk.internal.org.objectweb.asm.Type;
37 import jdk.internal.org.objectweb.asm.commons.GeneratorAdapter;
38 import jdk.internal.org.objectweb.asm.commons.Method;
39 import jdk.jfr.AnnotationElement;
40 import jdk.jfr.Event;
41 import jdk.jfr.ValueDescriptor;
42
43
44 // Helper class for building dynamic events
45 public final class EventClassBuilder {
46
47 private static final Type TYPE_EVENT = Type.getType(Event.class);
48 private static final Type TYPE_IOBE = Type.getType(IndexOutOfBoundsException.class);
49 private static final Method DEFAULT_CONSTRUCTOR = Method.getMethod("void <init> ()");
50 private static final Method SET_METHOD = Method.getMethod("void set (int, java.lang.Object)");
51 private static final AtomicLong idCounter = new AtomicLong();
52 private final ClassWriter classWriter = new ClassWriter(ClassWriter.COMPUTE_MAXS | ClassWriter.COMPUTE_FRAMES);
53 private final String fullClassName;
54 private final Type type;
55 private final List<ValueDescriptor> fields;
56 private final List<AnnotationElement> annotationElements;
57
58 public EventClassBuilder(List<AnnotationElement> annotationElements, List<ValueDescriptor> fields) {
59 this.fullClassName = "jdk.jfr.DynamicEvent" + idCounter.incrementAndGet();
60 this.type = Type.getType(fullClassName.replace(".", "/"));
61 this.fields = fields;
62 this.annotationElements = annotationElements;
63 }
64
65 public Class<? extends Event> build() {
66 buildClassInfo();
67 buildConstructor();
68 buildFields();
69 buildSetMethod();
70 endClass();
71 byte[] bytes = classWriter.toByteArray();
72 ASMToolkit.logASM(fullClassName, bytes);
73 return SecuritySupport.defineClass(type.getInternalName(), bytes, Event.class.getClassLoader()).asSubclass(Event.class);
74 }
75
76 private void endClass() {
77 classWriter.visitEnd();
78 }
79
80 private void buildSetMethod() {
81 GeneratorAdapter ga = new GeneratorAdapter(Opcodes.ACC_PUBLIC, SET_METHOD, null, null, classWriter);
82 int index = 0;
83 for (ValueDescriptor v : fields) {
84 ga.loadArg(0);
85 ga.visitLdcInsn(index);
86 Label notEqual = new Label();
87 ga.ifICmp(GeneratorAdapter.NE, notEqual);
88 ga.loadThis();
89 ga.loadArg(1);
90 Type fieldType = ASMToolkit.toType(v);
91 ga.unbox(ASMToolkit.toType(v));
92 ga.putField(type, v.getName(), fieldType);
93 ga.visitInsn(Opcodes.RETURN);
94 ga.visitLabel(notEqual);
95 index++;
96 }
97 ga.throwException(TYPE_IOBE, "Index must between 0 and " + fields.size());
98 ga.endMethod();
99 }
100
101 private void buildConstructor() {
102 MethodVisitor mv = classWriter.visitMethod(Opcodes.ACC_PUBLIC, DEFAULT_CONSTRUCTOR.getName(), DEFAULT_CONSTRUCTOR.getDescriptor(), null, null);
103 mv.visitIntInsn(Opcodes.ALOAD, 0);
104 ASMToolkit.invokeSpecial(mv, TYPE_EVENT.getInternalName(), DEFAULT_CONSTRUCTOR);
105 mv.visitInsn(Opcodes.RETURN);
106 mv.visitMaxs(0, 0);
107 }
108
109 private void buildClassInfo() {
110 String internalSuperName = ASMToolkit.getInternalName(Event.class.getName());
111 String internalClassName = type.getInternalName();
112 classWriter.visit(52, Opcodes.ACC_PUBLIC + Opcodes.ACC_FINAL + Opcodes.ACC_SUPER, internalClassName, null, internalSuperName, null);
113
114 for (AnnotationElement a : annotationElements) {
115 String descriptor = ASMToolkit.getDescriptor(a.getTypeName());
116 AnnotationVisitor av = classWriter.visitAnnotation(descriptor, true);
117 for (ValueDescriptor v : a.getValueDescriptors()) {
118 Object value = a.getValue(v.getName());
119 String name = v.getName();
120 if (v.isArray()) {
121 AnnotationVisitor arrayVisitor = av.visitArray(name);
122 Object[] array = (Object[]) value;
123 for (int i = 0; i < array.length; i++) {
124 arrayVisitor.visit(null, array[i]);
125 }
126 arrayVisitor.visitEnd();
127 } else {
128 av.visit(name, value);
129 }
130 }
131 av.visitEnd();
132 }
133 }
134
135 private void buildFields() {
136 for (ValueDescriptor v : fields) {
137 String internal = ASMToolkit.getDescriptor(v.getTypeName());
138 classWriter.visitField(Opcodes.ACC_PRIVATE, v.getName(), internal, null, null);
139 // No need to store annotations on field since they will be replaced anyway.
140 }
141 }
142 }