package edu.umd.cs.findbugs.detect;
import static org.apache.bcel.Constants.*;
import java.util.BitSet;
import java.util.Iterator;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InvokeInstruction;
import org.apache.bcel.generic.MethodGen;
import edu.umd.cs.findbugs.BugAnnotation;
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.SystemProperties;
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.Location;
import edu.umd.cs.findbugs.ba.MethodUnprofitableException;
import edu.umd.cs.findbugs.ba.SignatureParser;
import edu.umd.cs.findbugs.ba.XField;
import edu.umd.cs.findbugs.ba.vna.ValueNumber;
import edu.umd.cs.findbugs.ba.vna.ValueNumberDataflow;
import edu.umd.cs.findbugs.ba.vna.ValueNumberFrame;
import edu.umd.cs.findbugs.ba.vna.ValueNumberSourceInfo;
public class FindSelfComparison2 implements Detector {
private final BugReporter bugReporter;
public FindSelfComparison2(BugReporter bugReporter) {
this.bugReporter = bugReporter;
}
@Override
public void visitClassContext(ClassContext classContext) {
Method[] methodList = classContext.getJavaClass().getMethods();
for (Method method : methodList) {
if (method.getCode() == null) {
continue;
}
try {
analyzeMethod(classContext, method);
} catch (MethodUnprofitableException mue) {
if (SystemProperties.getBoolean("unprofitable.debug")) {
// don't
// report
bugReporter.logError("skipping unprofitable method in " + getClass().getName());
}
} catch (CFGBuilderException e) {
bugReporter.logError("Detector " + this.getClass().getName() + " caught exception", e);
} catch (DataflowAnalysisException e) {
bugReporter.logError("Detector " + this.getClass().getName() + " caught exception", e);
}
}
}
static boolean booleanComparisonMethod(String methodName) {
return methodName.equals("equals") ||methodName.equals("endsWith") || methodName.equals("startsWith")
|| methodName.equals("contains") || methodName.equals("equalsIgnoreCase");
}
static boolean comparatorMethod(String methodName) {
return methodName.equals("compareTo") || methodName.equals("compareToIgnoreCase");
}
private void analyzeMethod(ClassContext classContext, Method method) throws CFGBuilderException, DataflowAnalysisException {
CFG cfg = classContext.getCFG(method);
ValueNumberDataflow valueNumberDataflow = classContext.getValueNumberDataflow(method);
ConstantPoolGen cpg = classContext.getConstantPoolGen();
MethodGen methodGen = classContext.getMethodGen(method);
String sourceFile = classContext.getJavaClass().getSourceFileName();
for (Iterator<Location> i = cfg.locationIterator(); i.hasNext();) {
Location location = i.next();
Instruction ins = location.getHandle().getInstruction();
switch (ins.getOpcode()) {
case INVOKEVIRTUAL:
case INVOKEINTERFACE:
InvokeInstruction iins = (InvokeInstruction) ins;
String invoking = iins.getName(cpg);
if ( comparatorMethod(invoking) || booleanComparisonMethod(invoking) ) {
if (methodGen.getName().toLowerCase().indexOf("test") >= 0) {
break;
}
if (methodGen.getClassName().toLowerCase().indexOf("test") >= 0) {
break;
}
if (classContext.getJavaClass().getSuperclassName().toLowerCase().indexOf("test") >= 0) {
break;
}
if (location.getHandle().getNext().getInstruction().getOpcode() == POP) {
break;
}
String sig = iins.getSignature(cpg);
SignatureParser parser = new SignatureParser(sig);
if (parser.getNumParameters() == 1
&& ( booleanComparisonMethod(invoking) && sig.endsWith(";)Z") || comparatorMethod(invoking) && sig.endsWith(";)I"))) {
checkForSelfOperation(classContext, location, valueNumberDataflow, "COMPARISON", method, methodGen,
sourceFile);
}
}
break;
case LOR:
case LAND:
case LXOR:
case LSUB:
case IOR:
case IAND:
case IXOR:
case ISUB:
checkForSelfOperation(classContext, location, valueNumberDataflow, "COMPUTATION", method, methodGen, sourceFile);
break;
case FCMPG:
case DCMPG:
case DCMPL:
case FCMPL:
break;
case LCMP:
case IF_ACMPEQ:
case IF_ACMPNE:
case IF_ICMPNE:
case IF_ICMPEQ:
case IF_ICMPGT:
case IF_ICMPLE:
case IF_ICMPLT:
case IF_ICMPGE:
checkForSelfOperation(classContext, location, valueNumberDataflow, "COMPARISON", method, methodGen, sourceFile);
break;
default:
break;
}
}
}
/**
* @param classContext
* @param location
* @param method
* @param methodGen
* @param sourceFile
* @throws DataflowAnalysisException
*/
private void checkForSelfOperation(ClassContext classContext, Location location, ValueNumberDataflow valueNumberDataflow,
String op, Method method, MethodGen methodGen, String sourceFile) throws DataflowAnalysisException {
ValueNumberFrame frame = valueNumberDataflow.getFactAtLocation(location);
if (!frame.isValid()) {
return;
}
Instruction ins = location.getHandle().getInstruction();
int opcode = ins.getOpcode();
int offset = 1;
if (opcode == LCMP || opcode == LXOR || opcode == LAND || opcode == LOR || opcode == LSUB) {
offset = 2;
}
ValueNumber v0 = frame.getStackValue(0);
ValueNumber v1 = frame.getStackValue(offset);
if (!v1.equals(v0)) {
return;
}
if (v0.hasFlag(ValueNumber.CONSTANT_CLASS_OBJECT) || v0.hasFlag(ValueNumber.CONSTANT_VALUE)) {
return;
}
int priority = HIGH_PRIORITY;
if (opcode == ISUB || opcode == LSUB || opcode == INVOKEINTERFACE || opcode == INVOKEVIRTUAL) {
priority = NORMAL_PRIORITY;
}
XField field = ValueNumberSourceInfo.findXFieldFromValueNumber(method, location, v0, frame);
BugAnnotation annotation;
String prefix;
if (field != null) {
if (field.isVolatile()) {
return;
}
if (true) {
return; // don't report these; too many false positives
}
// annotation = FieldAnnotation.fromXField(field);
// prefix = "SA_FIELD_SELF_";
} else {
annotation = ValueNumberSourceInfo.findLocalAnnotationFromValueNumber(method, location, v0, frame);
prefix = "SA_LOCAL_SELF_";
if (opcode == ISUB) {
return; // only report this if simple detector reports it
}
}
if (annotation == null) {
return;
}
SourceLineAnnotation sourceLine = SourceLineAnnotation.fromVisitedInstruction(classContext, methodGen, sourceFile,
location.getHandle());
int line = sourceLine.getStartLine();
BitSet occursMultipleTimes = classContext.linesMentionedMultipleTimes(method);
if (line > 0 && occursMultipleTimes.get(line)) {
return;
}
BugInstance bug = new BugInstance(this, prefix + op, priority).addClassAndMethod(methodGen, sourceFile);
if (ins instanceof InvokeInstruction) {
bug.addCalledMethod(classContext.getConstantPoolGen(), (InvokeInstruction) ins);
}
bug.add(annotation)
.addSourceLine(classContext, methodGen, sourceFile, location.getHandle());
bugReporter.reportBug(bug);
}
@Override
public void report() {
}
}