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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package jdk.jfr.internal.instrument;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import jdk.internal.org.objectweb.asm.ClassVisitor;
import jdk.internal.org.objectweb.asm.MethodVisitor;
import jdk.internal.org.objectweb.asm.Opcodes;
import jdk.internal.org.objectweb.asm.Type;
import jdk.internal.org.objectweb.asm.commons.RemappingMethodAdapter;
import jdk.internal.org.objectweb.asm.commons.SimpleRemapper;
import jdk.internal.org.objectweb.asm.tree.ClassNode;
import jdk.internal.org.objectweb.asm.tree.MethodNode;
import jdk.jfr.internal.LogLevel;
import jdk.jfr.internal.LogTag;
import jdk.jfr.internal.Logger;

This class will merge (some) methods from one class into another one.
Author:Staffan Larsen
/** * This class will merge (some) methods from one class into another one. * * @author Staffan Larsen */
@Deprecated final class JIMethodMergeAdapter extends ClassVisitor { private final ClassNode cn; private final List<Method> methodFilter; private final Map<String, String> typeMap;
Methods in methodFilter that exist in cn will be merged into cv. If the method already exists, the original method will be deleted.
Params:
  • cv –
  • cn – - a ClassNode with Methods that will be merged into this class
  • methodFilter – - only methods in this list will be merged
  • typeMappings – - while merging, type references in the methods will be changed according to this map
/** * Methods in methodFilter that exist in cn will be merged into cv. If the method already exists, * the original method will be deleted. * * @param cv * @param cn - a ClassNode with Methods that will be merged into this class * @param methodFilter - only methods in this list will be merged * @param typeMappings - while merging, type references in the methods will be changed according to this map */
public JIMethodMergeAdapter(ClassVisitor cv, ClassNode cn, List<Method> methodFilter, JITypeMapping[] typeMappings) { super(Opcodes.ASM7, cv); this.cn = cn; this.methodFilter = methodFilter; this.typeMap = new HashMap<>(); for (JITypeMapping tm : typeMappings) { typeMap.put(tm.from().replace('.', '/'), tm.to().replace('.', '/')); } } @Override public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) { super.visit(version, access, name, signature, superName, interfaces); typeMap.put(cn.name, name); } @Override public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) { if(methodInFilter(name, desc)) { // If the method is one that we will be replacing, delete the method Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Deleting " + name + desc); return null; } return super.visitMethod(access, name, desc, signature, exceptions); } @Override public void visitEnd() { SimpleRemapper remapper = new SimpleRemapper(typeMap); for (MethodNode mn : cn.methods) { // Check if the method is in the list of methods to copy if (methodInFilter(mn.name, mn.desc)) { if (Logger.shouldLog(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG)) { Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, "Copying method: " + mn.name + mn.desc); Logger.log(LogTag.JFR_SYSTEM_BYTECODE, LogLevel.DEBUG, " with mapper: " + typeMap); } String[] exceptions = new String[mn.exceptions.size()]; mn.exceptions.toArray(exceptions); MethodVisitor mv = cv.visitMethod(mn.access, mn.name, mn.desc, mn.signature, exceptions); mn.instructions.resetLabels(); mn.accept(new RemappingMethodAdapter(mn.access, mn.desc, mv, remapper)); } } super.visitEnd(); } private boolean methodInFilter(String name, String desc) { for(Method m : methodFilter) { if (m.getName().equals(name) && Type.getMethodDescriptor(m).equals(desc)) { return true; } } return false; } }