/*
* FindBugs - Find bugs in Java programs
* Copyright (C) 2004-2006 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 org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.LineNumberTable;
import edu.umd.cs.findbugs.BugAccumulator;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.FieldAnnotation;
import edu.umd.cs.findbugs.LocalVariableAnnotation;
import edu.umd.cs.findbugs.OpcodeStack;
import edu.umd.cs.findbugs.SourceLineAnnotation;
import edu.umd.cs.findbugs.SystemProperties;
import edu.umd.cs.findbugs.ba.SignatureParser;
import edu.umd.cs.findbugs.ba.XClass;
import edu.umd.cs.findbugs.ba.XField;
import edu.umd.cs.findbugs.bcel.OpcodeStackDetector;
import edu.umd.cs.findbugs.util.EditDistance;
import edu.umd.cs.findbugs.util.Util;
public class FindSelfComparison extends OpcodeStackDetector {
final BugAccumulator bugAccumulator;
public FindSelfComparison(BugReporter bugReporter) {
this.bugAccumulator = new BugAccumulator(bugReporter);
}
int putFieldPC = Integer.MIN_VALUE;
OpcodeStack.Item putFieldObj;
OpcodeStack.Item putFieldValue;
XField putFieldXField;
int lastMethodCall;
static final boolean DEBUG = SystemProperties.getBoolean("fsc.debug");
@Override
public void visit(Code obj) {
if (DEBUG)
System.out.println(getFullyQualifiedMethodName());
whichRegister = -1;
registerLoadCount = 0;
lastMethodCall = -1;
resetDoubleAssignmentState();
super.visit(obj);
resetDoubleAssignmentState();
bugAccumulator.reportAccumulatedBugs();
if (DEBUG)
System.out.println();
}
private void resetDoubleAssignmentState() {
putFieldPC = Integer.MIN_VALUE;
putFieldXField = null;
putFieldValue = null;
putFieldObj = null;
}
@Override
public void sawBranchTo(int target) {
resetDoubleAssignmentState();
}
@Override
public void sawOpcode(int seen) {
if (DEBUG)
System.out.printf("%3d %-15s %s%n", getPC(), OPCODE_NAMES[seen], stack);
if (stack.hasIncomingBranches(getPC()))
resetDoubleAssignmentState();
if (seen == PUTFIELD) {
OpcodeStack.Item obj = stack.getStackItem(1);
OpcodeStack.Item value = stack.getStackItem(0);
XField f = getXFieldOperand();
XClass x = getXClassOperand();
checkPUTFIELD: if (putFieldPC + 10 > getPC() && f != null && obj != null && f.equals(putFieldXField)
&& !f.isSynthetic() && obj.equals(putFieldObj) && x != null) {
LineNumberTable table = getCode().getLineNumberTable();
if (table != null) {
int first = table.getSourceLine(putFieldPC);
int second = table.getSourceLine(getPC());
if (first + 1 != second && first != second)
break checkPUTFIELD;
} else if (putFieldPC + 3 != getPC())
break checkPUTFIELD;
int priority = NORMAL_PRIORITY;
if (value.equals(putFieldValue) && putFieldPC + 3 != getPC())
priority++;
boolean storeOfDefaultValue = putFieldValue.isNull() || putFieldValue.hasConstantValue(0);
if (storeOfDefaultValue)
priority++;
if (f.isVolatile())
priority++;
XField intendedTarget = null;
double minimumDistance = 2;
int matches = 0;
for (XField f2 : x.getXFields())
if (!f.equals(f2) && !f2.isStatic() && !f2.isFinal() && !f2.isSynthetic()
&& f2.getSignature().equals(f.getSignature())) {
double distance = EditDistance.editDistanceRatio(f.getName(), f2.getName());
matches++;
if (minimumDistance > distance) {
minimumDistance = distance;
intendedTarget = f2;
}
}
if (minimumDistance > 0.6 && (matches > 1 || storeOfDefaultValue))
intendedTarget = null;
else if (intendedTarget != null)
priority--;
BugInstance bug = new BugInstance(this, "SA_FIELD_DOUBLE_ASSIGNMENT", priority).addClassAndMethod(this)
.addReferencedField(this);
if (intendedTarget != null)
bug.addField(intendedTarget).describe(FieldAnnotation.DID_YOU_MEAN_ROLE);
bugAccumulator.accumulateBug(bug, this);
}
putFieldPC = getPC();
putFieldXField = f;
putFieldObj = obj;
putFieldValue = value;
} else if (isReturn(seen))
resetDoubleAssignmentState();
else if (seen == GETFIELD && Util.nullSafeEquals(getXFieldOperand(), putFieldXField)) {
OpcodeStack.Item obj = stack.getStackItem(0);
if (obj.equals(putFieldObj))
resetDoubleAssignmentState();
}
switch (seen) {
case INVOKEVIRTUAL:
case INVOKEINTERFACE:
// case INVOKESTATIC:
if (getClassName().toLowerCase().indexOf("test") >= 0)
break;
if (getMethodName().toLowerCase().indexOf("test") >= 0)
break;
if (getSuperclassName().toLowerCase().indexOf("test") >= 0)
break;
if (getNextOpcode() == POP)
break;
String name = getNameConstantOperand();
boolean booleanComparisonMethod = FindSelfComparison2.booleanComparisonMethod(name);
if (booleanComparisonMethod || FindSelfComparison2.comparatorMethod(name)) {
String sig = getSigConstantOperand();
SignatureParser parser = new SignatureParser(sig);
int numParameters = parser.getNumParameters();
if ((numParameters == 1 || seen == INVOKESTATIC && numParameters == 2)
&& (booleanComparisonMethod && sig.endsWith(";)Z")
|| FindSelfComparison2.comparatorMethod(name) && sig.endsWith(";)I")))
checkForSelfOperation(seen, "COMPARISON");
}
break;
case LOR:
case LAND:
case LXOR:
case LSUB:
case IOR:
case IAND:
case IXOR:
case ISUB:
checkForSelfOperation(seen, "COMPUTATION");
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(seen, "COMPARISON");
}
if (isRegisterLoad() && seen != IINC) {
if (getRegisterOperand() == whichRegister)
registerLoadCount++;
else {
whichRegister = getRegisterOperand();
registerLoadCount = 1;
}
} else {
whichRegister = -1;
registerLoadCount = 0;
}
if (isMethodCall())
lastMethodCall = getPC();
}
int whichRegister;
int registerLoadCount;
private void checkForSelfOperation(int opCode, String op) {
{
OpcodeStack.Item item0 = stack.getStackItem(0);
OpcodeStack.Item item1 = stack.getStackItem(1);
if (item0.getSignature().equals("D") || item0.getSignature().equals("F"))
return;
if (item1.getSignature().equals("D") || item1.getSignature().equals("F"))
return;
BitSet linesMentionedMultipleTimes = getClassContext().linesMentionedMultipleTimes(getMethod());
SourceLineAnnotation source = SourceLineAnnotation.fromVisitedInstruction(this);
boolean possibleClone = source.getStartLine() > 0 && linesMentionedMultipleTimes.get(source.getStartLine());
LineNumberTable lineNumberTable = getCode().getLineNumberTable();
int linesDifference = 0;
if (item0.getPC() != -1 && item1.getPC() != -1) {
if (lineNumberTable != null) {
int line0 = lineNumberTable.getSourceLine(item0.getPC());
int line1 = lineNumberTable.getSourceLine(item1.getPC());
int firstPos = Math.min(item0.getPC(), item1.getPC());
if (firstPos < lastMethodCall && line0 != line1)
return;
linesDifference = Math.abs(line0 - line1);
} else {
int firstPos = Math.min(item0.getPC(), item1.getPC());
int lastPos = Math.max(item0.getPC(), item1.getPC());
if (firstPos < lastMethodCall && lastPos - firstPos > 4)
return;
linesDifference = (lastPos - firstPos)/10;
}
}
XField field0 = item0.getXField();
XField field1 = item1.getXField();
int fr0 = item0.getFieldLoadedFromRegister();
int fr1 = item1.getFieldLoadedFromRegister();
if (field0 != null && field0.equals(field1) && (field0.isStatic() || fr0 != -1 && fr0 == fr1)) {
int priority = NORMAL_PRIORITY;
if (field0.isVolatile())
priority++;
if (linesDifference > 1) {
if (possibleClone)
return;
priority++;
}
BugInstance bug = new BugInstance(this, "SA_FIELD_SELF_" + op, priority)
.addClassAndMethod(this).addField(field0);
if (this.isMethodCall())
bug.addCalledMethod(this);
bugAccumulator.accumulateBug(bug, this);
}
else if (opCode == IXOR && item0.equals(item1)) {
LocalVariableAnnotation localVariableAnnotation = LocalVariableAnnotation.getLocalVariableAnnotation(this, item0);
if (localVariableAnnotation != null)
bugAccumulator.accumulateBug(
new BugInstance(this, "SA_LOCAL_SELF_" + op, linesDifference > 1 ? NORMAL_PRIORITY : HIGH_PRIORITY).addClassAndMethod(this).add(
localVariableAnnotation), this);
}
}
}
}