Java tutorial
/* * Minha.pt: middleware testing platform. * Copyright (c) 2011-2014, Universidade do Minho. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 2 * of the License, or (at your option) any later version. * * This program 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 for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ package pt.minha.kernel.instrument; import org.objectweb.asm.ClassVisitor; import org.objectweb.asm.FieldVisitor; import org.objectweb.asm.Label; import org.objectweb.asm.MethodVisitor; import org.objectweb.asm.Opcodes; import org.objectweb.asm.Type; import org.objectweb.asm.commons.Method; public class SyncToMonitorClassVisitor extends ClassVisitor { private String clz; private boolean hasClinit; private int access; private Translation trans; public SyncToMonitorClassVisitor(ClassVisitor visitor, Translation trans) { super(Opcodes.ASM5, visitor); this.trans = trans; } public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) { if (trans.isSynchronized()) { clz = name; this.access = access; if ((access & Opcodes.ACC_INTERFACE) == 0) { FieldVisitor fv = visitField(Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, "_fake_class", "L" + ClassConfig.fake_prefix + "java/lang/Object;", null, null); fv.visitEnd(); } } super.visit(version, access, name, signature, superName, interfaces); } public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) { if (trans.isSynchronized()) { if (name.equals("<clinit>")) { hasClinit = true; return new ClinitVisitor(super.visitMethod(access, name, desc, signature, exceptions)); } if ((access & Opcodes.ACC_SYNCHRONIZED) != 0) { makeStub(access & ~Opcodes.ACC_SYNCHRONIZED, name, desc, signature, exceptions); return super.visitMethod( (access & ~(Opcodes.ACC_SYNCHRONIZED | Opcodes.ACC_PUBLIC | Opcodes.ACC_PROTECTED) | Opcodes.ACC_FINAL | Opcodes.ACC_SYNTHETIC | Opcodes.ACC_PRIVATE), "_" + name, desc, signature, exceptions); } } return super.visitMethod(access, name, desc, signature, exceptions); } public void visitEnd() { if (trans.isSynchronized()) { if (!hasClinit && (access & Opcodes.ACC_INTERFACE) == 0) mkClinit(); } super.visitEnd(); } private void mkClinit() { MethodVisitor mv = visitMethod(Opcodes.ACC_STATIC, "<clinit>", "()V", null, null); mv.visitCode(); mv.visitInsn(Opcodes.RETURN); mv.visitMaxs(0, 0); mv.visitEnd(); } private class ClinitVisitor extends MethodVisitor { public ClinitVisitor(MethodVisitor arg0) { super(Opcodes.ASM5, arg0); } public void visitCode() { super.visitCode(); if ((access & Opcodes.ACC_INTERFACE) != 0) return; mv.visitTypeInsn(Opcodes.NEW, ClassConfig.fake_prefix + "java/lang/Object"); mv.visitInsn(Opcodes.DUP); mv.visitMethodInsn(Opcodes.INVOKESPECIAL, ClassConfig.fake_prefix + "java/lang/Object", "<init>", "()V", false); mv.visitFieldInsn(Opcodes.PUTSTATIC, clz, "_fake_class", "L" + ClassConfig.fake_prefix + "java/lang/Object;"); } } public void makeStub(int access, String name, String desc, String signature, String[] exceptions) { Method m = new Method(name, desc); MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions); mv.visitCode(); Label begin = new Label(); Label pre_invoke = new Label(); Label pos_leave = new Label(); Label in_catch = new Label(); Label pre_rethrow = new Label(); Label end = new Label(); mv.visitTryCatchBlock(pre_invoke, pos_leave, in_catch, null); mv.visitTryCatchBlock(in_catch, pre_rethrow, in_catch, null); mv.visitLabel(begin); int offset; if ((access & Opcodes.ACC_STATIC) == 0) { mv.visitVarInsn(Opcodes.ALOAD, 0); offset = 1; } else { mv.visitFieldInsn(Opcodes.GETSTATIC, clz, "_fake_class", "L" + ClassConfig.fake_prefix + "java/lang/Object;"); offset = 0; } int length = 0; for (Type t : m.getArgumentTypes()) length += t.getSize(); mv.visitInsn(Opcodes.DUP); mv.visitVarInsn(Opcodes.ASTORE, offset + length); mv.visitInsn(Opcodes.MONITORENTER); mv.visitLabel(pre_invoke); if ((access & Opcodes.ACC_STATIC) == 0) mv.visitVarInsn(Opcodes.ALOAD, 0); int i = offset; for (Type t : m.getArgumentTypes()) { // t.getOpcode() should work for long and double too... :-( if (t.getClassName().equals("long")) mv.visitVarInsn(Opcodes.LLOAD, i); else if (t.getClassName().equals("double")) mv.visitVarInsn(Opcodes.DLOAD, i); else mv.visitVarInsn(t.getOpcode(Opcodes.ILOAD), i); i += t.getSize(); } boolean itf = (access & Opcodes.ACC_INTERFACE) != 0; if ((access & Opcodes.ACC_STATIC) == 0) mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, clz, "_" + name, desc, itf); else mv.visitMethodInsn(Opcodes.INVOKESTATIC, clz, "_" + name, desc, itf); mv.visitVarInsn(Opcodes.ALOAD, offset + length); mv.visitInsn(Opcodes.MONITOREXIT); mv.visitLabel(pos_leave); if (m.getReturnType().equals(Type.VOID_TYPE)) mv.visitInsn(Opcodes.RETURN); else mv.visitInsn(m.getReturnType().getOpcode(Opcodes.IRETURN)); mv.visitLabel(in_catch); mv.visitVarInsn(Opcodes.ALOAD, offset + length); mv.visitInsn(Opcodes.MONITOREXIT); mv.visitLabel(pre_rethrow); mv.visitInsn(Opcodes.ATHROW); mv.visitLabel(end); i = 0; if ((access & Opcodes.ACC_STATIC) == 0) mv.visitLocalVariable("this", "L" + clz + ";", null, begin, end, i++); for (Type t : m.getArgumentTypes()) mv.visitLocalVariable("arg" + i, t.getDescriptor(), null, begin, end, i++); mv.visitMaxs(0, 0); mv.visitEnd(); } }