Java tutorial
/** License information: * Component: checkedcoverage-tracer * Package: pku.sei.checkedcoverage.tracer.instrumentation * Class: PauseTracingInstrumenter * Filename: checkedcoverage-tracer/src/main/java/de/unisb/cs/st/checkedcoverage/tracer/instrumentation/PauseTracingInstrumenter.java * * This file is part of the checkedcoverage tool, developed by Clemens Hammacher at Saarland University. * See http://www.st.cs.uni-saarland.de/checkedcoverage/ for more information. * * This work is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License. * To view a copy of this license, visit http://creativecommons.org/licenses/by-sa/3.0/ or send a * letter to Creative Commons, 171 Second Street, Suite 300, San Francisco, California, 94105, USA. */ package pku.sei.checkedcoverage.tracer.instrumentation; import java.util.Arrays; import java.util.HashMap; import java.util.Iterator; import java.util.ListIterator; import java.util.Map; import org.apache.commons.collections.Factory; import org.apache.commons.collections.map.LazyMap; import org.objectweb.asm.Opcodes; import org.objectweb.asm.Type; import org.objectweb.asm.tree.AbstractInsnNode; import org.objectweb.asm.tree.ClassNode; import org.objectweb.asm.tree.IincInsnNode; import org.objectweb.asm.tree.InsnNode; import org.objectweb.asm.tree.LabelNode; import org.objectweb.asm.tree.LocalVariableNode; import org.objectweb.asm.tree.MethodInsnNode; import org.objectweb.asm.tree.MethodNode; import org.objectweb.asm.tree.TryCatchBlockNode; import org.objectweb.asm.tree.VarInsnNode; import pku.sei.checkedcoverage.common.classRepresentation.ReadClass; import pku.sei.checkedcoverage.tracer.ThreadTracer; import pku.sei.checkedcoverage.tracer.Tracer; /** * This class instruments methods to stop tracing as soon as the method is entered * and continue when it is left (either by a return statement or by a thrown exception). * * @author Clemens Hammacher */ public class PauseTracingInstrumenter implements Opcodes { private final Tracer tracer; public PauseTracingInstrumenter(final ReadClass readClass, final Tracer tracer) { this.tracer = tracer; if (tracer.debug && readClass != null) System.out.println("instrumenting " + readClass.getName() + " (pause tracing)"); } @SuppressWarnings("unchecked") public void transform(final ClassNode classNode) { final ListIterator<MethodNode> methodIt = classNode.methods.listIterator(); while (methodIt.hasNext()) { final MethodNode method = methodIt.next(); transformMethod(method, methodIt, Type.getObjectType(classNode.name).getClassName()); } } @SuppressWarnings("unchecked") public void transformMethod(final MethodNode method, final ListIterator<MethodNode> methodIt, final String className) { if ((method.access & ACC_ABSTRACT) != 0 || (method.access & ACC_NATIVE) != 0) return; int tracerLocalVarIndex = (method.access & Opcodes.ACC_STATIC) == 0 ? 1 : 0; for (final Type t : Type.getArgumentTypes(method.desc)) tracerLocalVarIndex += t.getSize(); // increment number of local variables by one (for the threadtracer) ++method.maxLocals; // and increment all local variable indexes after the new one by one for (final Object o : method.localVariables) { final LocalVariableNode localVar = (LocalVariableNode) o; if (localVar.index >= tracerLocalVarIndex) ++localVar.index; } final LabelNode l0 = new LabelNode(); final LabelNode l1 = new LabelNode(); final ListIterator<AbstractInsnNode> insnIt = method.instructions.iterator(); insnIt.add(new MethodInsnNode(INVOKESTATIC, Type.getInternalName(Tracer.class), "getInstance", "()L" + Type.getInternalName(Tracer.class) + ";")); insnIt.add(new MethodInsnNode(INVOKEVIRTUAL, Type.getInternalName(Tracer.class), "getThreadTracer", "()L" + Type.getInternalName(ThreadTracer.class) + ";")); insnIt.add(new InsnNode(DUP)); insnIt.add(new VarInsnNode(ASTORE, tracerLocalVarIndex)); insnIt.add(new MethodInsnNode(INVOKEINTERFACE, Type.getInternalName(ThreadTracer.class), "pauseTracing", "()V")); insnIt.add(l0); while (insnIt.hasNext()) { final AbstractInsnNode insn = insnIt.next(); switch (insn.getType()) { case AbstractInsnNode.INSN: switch (insn.getOpcode()) { case IRETURN: case LRETURN: case FRETURN: case DRETURN: case ARETURN: case RETURN: insnIt.previous(); insnIt.add(new VarInsnNode(ALOAD, tracerLocalVarIndex)); insnIt.add(new MethodInsnNode(INVOKEINTERFACE, Type.getInternalName(ThreadTracer.class), "resumeTracing", "()V")); insnIt.next(); } break; case AbstractInsnNode.IINC_INSN: if (((IincInsnNode) insn).var >= tracerLocalVarIndex) ++((IincInsnNode) insn).var; break; case AbstractInsnNode.VAR_INSN: if (((VarInsnNode) insn).var >= tracerLocalVarIndex) ++((VarInsnNode) insn).var; break; default: break; } } method.instructions.add(l1); method.instructions.add(new VarInsnNode(ALOAD, tracerLocalVarIndex)); method.instructions.add(new MethodInsnNode(INVOKEINTERFACE, Type.getInternalName(ThreadTracer.class), "resumeTracing", "()V")); method.instructions.add(new InsnNode(ATHROW)); method.tryCatchBlocks.add(new TryCatchBlockNode(l0, l1, l1, null)); // finally: create a copy of the method that gets the ThreadTracer as argument if (!"<clinit>".equals(method.name) && this.tracer.wasRedefined(className)) { final Type[] oldMethodArguments = Type.getArgumentTypes(method.desc); final Type[] newMethodArguments = Arrays.copyOf(oldMethodArguments, oldMethodArguments.length + 1); newMethodArguments[oldMethodArguments.length] = Type.getType(ThreadTracer.class); final String newMethodDesc = Type.getMethodDescriptor(Type.getReturnType(method.desc), newMethodArguments); final MethodNode newMethod = new MethodNode(method.access, method.name, newMethodDesc, method.signature, (String[]) method.exceptions.toArray(new String[method.exceptions.size()])); methodIt.add(newMethod); final Map<LabelNode, LabelNode> newMethodLabels = LazyMap.decorate(new HashMap<LabelNode, LabelNode>(), new Factory() { public Object create() { return new LabelNode(); } }); // copy the local variables information to the new method for (final Object o : method.localVariables) { final LocalVariableNode lv = (LocalVariableNode) o; newMethod.localVariables.add(new LocalVariableNode(lv.name, lv.desc, lv.signature, newMethodLabels.get(lv.start), newMethodLabels.get(lv.end), lv.index)); } newMethod.maxLocals = method.maxLocals; newMethod.maxStack = method.maxStack; // copy the try-catch-blocks for (final Object o : method.tryCatchBlocks) { final TryCatchBlockNode tcb = (TryCatchBlockNode) o; newMethod.tryCatchBlocks.add(new TryCatchBlockNode(newMethodLabels.get(tcb.start), newMethodLabels.get(tcb.end), newMethodLabels.get(tcb.handler), tcb.type)); } // skip the first 4 instructions, replace them with this: newMethod.instructions.add(new VarInsnNode(ALOAD, tracerLocalVarIndex)); final Iterator<AbstractInsnNode> oldInsnIt = method.instructions.iterator(4); // and add all the other instructions while (oldInsnIt.hasNext()) { final AbstractInsnNode insn = oldInsnIt.next(); newMethod.instructions.add(insn.clone(newMethodLabels)); } } } }