/*
* FindBugs - Find bugs in Java programs
* Copyright (C) 2003-2005 University of Maryland
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package edu.umd.cs.findbugs.detect;
import java.util.BitSet;
import java.util.Collection;
import java.util.Iterator;
import org.apache.bcel.Constants;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.INVOKEVIRTUAL;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.MethodGen;
import edu.umd.cs.findbugs.BugAccumulator;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.Detector;
import edu.umd.cs.findbugs.SourceLineAnnotation;
import edu.umd.cs.findbugs.StatelessDetector;
import edu.umd.cs.findbugs.ba.CFG;
import edu.umd.cs.findbugs.ba.CFGBuilderException;
import edu.umd.cs.findbugs.ba.ClassContext;
import edu.umd.cs.findbugs.ba.DataflowAnalysisException;
import edu.umd.cs.findbugs.ba.Hierarchy;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.LockDataflow;
import edu.umd.cs.findbugs.ba.LockSet;
import edu.umd.cs.findbugs.ba.vna.ValueNumber;
import edu.umd.cs.findbugs.ba.vna.ValueNumberDataflow;
import edu.umd.cs.findbugs.ba.vna.ValueNumberFrame;
public final class FindMismatchedWaitOrNotify implements Detector, StatelessDetector {
private final BugReporter bugReporter;
private final BugAccumulator bugAccumulator;
public FindMismatchedWaitOrNotify(BugReporter bugReporter) {
this.bugReporter = bugReporter;
this.bugAccumulator = new BugAccumulator(bugReporter);
}
@Override
public Object clone() {
try {
return super.clone();
} catch (CloneNotSupportedException e) {
throw new AssertionError(e);
}
}
@Override
public void visitClassContext(ClassContext classContext) {
JavaClass jclass = classContext.getJavaClass();
Method[] methodList = jclass.getMethods();
for (Method method : methodList) {
MethodGen methodGen = classContext.getMethodGen(method);
if (methodGen == null) {
continue;
}
// Don't bother analyzing the method unless there is both locking
// and a method call.
BitSet bytecodeSet = classContext.getBytecodeSet(method);
if (bytecodeSet == null) {
continue;
}
if (!(bytecodeSet.get(Constants.MONITORENTER) && bytecodeSet.get(Constants.INVOKEVIRTUAL))) {
continue;
}
try {
analyzeMethod(classContext, method);
} catch (DataflowAnalysisException e) {
bugReporter.logError("FindMismatchedWaitOrNotify: caught exception", e);
} catch (CFGBuilderException e) {
bugReporter.logError("FindMismatchedWaitOrNotify: caught exception", e);
}
}
}
private void analyzeMethod(ClassContext classContext, Method method) throws CFGBuilderException, DataflowAnalysisException {
MethodGen methodGen = classContext.getMethodGen(method);
if (methodGen == null) {
return;
}
ConstantPoolGen cpg = methodGen.getConstantPool();
CFG cfg = classContext.getCFG(method);
ValueNumberDataflow vnaDataflow = classContext.getValueNumberDataflow(method);
LockDataflow dataflow = classContext.getLockDataflow(method);
for (Iterator<Location> i = cfg.locationIterator(); i.hasNext();) {
Location location = i.next();
InstructionHandle handle = location.getHandle();
Instruction ins = handle.getInstruction();
if (!(ins instanceof INVOKEVIRTUAL)) {
continue;
}
INVOKEVIRTUAL inv = (INVOKEVIRTUAL) ins;
String methodName = inv.getName(cpg);
String methodSig = inv.getSignature(cpg);
if (Hierarchy.isMonitorWait(methodName, methodSig) || Hierarchy.isMonitorNotify(methodName, methodSig)) {
int numConsumed = inv.consumeStack(cpg);
if (numConsumed == Constants.UNPREDICTABLE) {
throw new DataflowAnalysisException("Unpredictable stack consumption", methodGen, handle);
}
ValueNumberFrame frame = vnaDataflow.getFactAtLocation(location);
if (!frame.isValid()) {
// Probably dead code
continue;
}
if (frame.getStackDepth() - numConsumed < 0) {
throw new DataflowAnalysisException("Stack underflow", methodGen, handle);
}
ValueNumber ref = frame.getValue(frame.getNumSlots() - numConsumed);
LockSet lockSet = dataflow.getFactAtLocation(location);
int lockCount = lockSet.getLockCount(ref.getNumber());
if (lockCount == 0) {
Collection<ValueNumber> lockedValueNumbers = lockSet.getLockedValueNumbers(frame);
boolean foundMatch = false;
for (ValueNumber v : lockedValueNumbers) {
if (frame.veryFuzzyMatch(ref, v)) {
foundMatch = true;
break;
}
}
if (!foundMatch) {
String type = methodName.equals("wait") ? "MWN_MISMATCHED_WAIT" : "MWN_MISMATCHED_NOTIFY";
String sourceFile = classContext.getJavaClass().getSourceFileName();
// Report as medium priority only if the method is
// public.
// Non-public methods may be properly locked in a
// calling context.
int priority = method.isPublic() ? NORMAL_PRIORITY : LOW_PRIORITY;
bugAccumulator.accumulateBug(
new BugInstance(this, type, priority).addClassAndMethod(methodGen, sourceFile),
SourceLineAnnotation.fromVisitedInstruction(classContext, methodGen, sourceFile, handle));
}
}
}
}
bugAccumulator.reportAccumulatedBugs();
}
@Override
public void report() {
}
}