edu.umd.cs.findbugs.detect.FindDeadLocalStores Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of spotbugs Show documentation
Show all versions of spotbugs Show documentation
SpotBugs: Because it's easy!
The newest version!
/*
* FindBugs - Find bugs in Java programs
* Copyright (C) 2004,2005 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.HashSet;
import java.util.Iterator;
import java.util.Set;
import org.apache.bcel.Const;
import org.apache.bcel.classfile.ConstantClass;
import org.apache.bcel.classfile.Field;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.ACONST_NULL;
import org.apache.bcel.generic.ALOAD;
import org.apache.bcel.generic.ANEWARRAY;
import org.apache.bcel.generic.ASTORE;
import org.apache.bcel.generic.BasicType;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.ConstantPushInstruction;
import org.apache.bcel.generic.DUP;
import org.apache.bcel.generic.DUP2;
import org.apache.bcel.generic.GETFIELD;
import org.apache.bcel.generic.GETSTATIC;
import org.apache.bcel.generic.IINC;
import org.apache.bcel.generic.INVOKESPECIAL;
import org.apache.bcel.generic.IRETURN;
import org.apache.bcel.generic.IndexedInstruction;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InvokeInstruction;
import org.apache.bcel.generic.INVOKEDYNAMIC;
import org.apache.bcel.generic.LDC;
import org.apache.bcel.generic.LRETURN;
import org.apache.bcel.generic.LSTORE;
import org.apache.bcel.generic.LoadInstruction;
import org.apache.bcel.generic.MULTIANEWARRAY;
import org.apache.bcel.generic.MethodGen;
import org.apache.bcel.generic.NEWARRAY;
import org.apache.bcel.generic.ObjectType;
import org.apache.bcel.generic.Select;
import org.apache.bcel.generic.StoreInstruction;
import org.apache.bcel.generic.Type;
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.FieldAnnotation;
import edu.umd.cs.findbugs.FindBugsAnalysisFeatures;
import edu.umd.cs.findbugs.LocalVariableAnnotation;
import edu.umd.cs.findbugs.Priorities;
import edu.umd.cs.findbugs.SourceLineAnnotation;
import edu.umd.cs.findbugs.SwitchHandler;
import edu.umd.cs.findbugs.SystemProperties;
import edu.umd.cs.findbugs.ba.AnalysisContext;
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.Dataflow;
import edu.umd.cs.findbugs.ba.DataflowAnalysisException;
import edu.umd.cs.findbugs.ba.LiveLocalStoreAnalysis;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.ch.Subtypes2;
import edu.umd.cs.findbugs.ba.type.TypeDataflow;
import edu.umd.cs.findbugs.ba.type.TypeFrame;
import edu.umd.cs.findbugs.bcel.BCELUtil;
import edu.umd.cs.findbugs.internalAnnotations.StaticConstant;
import edu.umd.cs.findbugs.props.WarningProperty;
import edu.umd.cs.findbugs.props.WarningPropertySet;
import edu.umd.cs.findbugs.props.WarningPropertyUtil;
import edu.umd.cs.findbugs.util.ClassName;
import edu.umd.cs.findbugs.visitclass.PreorderVisitor;
/**
* Find dead stores to local variables.
*
* @author David Hovemeyer
* @author Bill Pugh
*/
public class FindDeadLocalStores implements Detector {
private static final boolean DEBUG = SystemProperties.getBoolean("fdls.debug");
// Define the name of the property that is used to exclude named local
// variables
// from Dead Local Storage detection...
private static final String FINDBUGS_EXCLUDED_LOCALS_PROP_NAME = "findbugs.dls.exclusions";
// Define a collection of excluded local variables...
@StaticConstant
private static final Set EXCLUDED_LOCALS = new HashSet<>();
// private static final boolean DO_EXCLUDE_LOCALS = SystemProperties.getProperty(FINDBUGS_EXCLUDED_LOCALS_PROP_NAME) != null;
static {
EXCLUDED_LOCALS.add("gxp_locale");
// Get the value of the property...
String exclLocalsProperty = SystemProperties.getProperty(FINDBUGS_EXCLUDED_LOCALS_PROP_NAME);
// If we have one, then split its contents into a list...
if (exclLocalsProperty != null) {
for (String s : exclLocalsProperty.split(",")) {
String s2 = s.trim();
if (s2.length() > 0) {
EXCLUDED_LOCALS.add(s2);
}
}
}
}
/**
* System property to enable a feature that suppresses warnings if there is
* at least one live store on the line where the warning would be reported.
* Eliminates some FPs due to inlining/duplication of finally blocks. But,
* kills some legitimate warnings where there are truly multiple stores on
* the same line.
*/
private static final boolean SUPPRESS_IF_AT_LEAST_ONE_LIVE_STORE_ON_LINE = SystemProperties
.getBoolean("findbugs.dls.suppressIfOneLiveStore");
// private static final Set classesAlreadyReportedOn = new
// HashSet();
/**
* Opcodes of instructions that load constant values that often indicate
* defensive programming.
*/
private static final BitSet defensiveConstantValueOpcodes = new BitSet();
static {
defensiveConstantValueOpcodes.set(Const.DCONST_0);
defensiveConstantValueOpcodes.set(Const.DCONST_1);
defensiveConstantValueOpcodes.set(Const.FCONST_0);
defensiveConstantValueOpcodes.set(Const.FCONST_1);
defensiveConstantValueOpcodes.set(Const.ACONST_NULL);
defensiveConstantValueOpcodes.set(Const.ICONST_M1);
defensiveConstantValueOpcodes.set(Const.ICONST_0);
defensiveConstantValueOpcodes.set(Const.ICONST_1);
defensiveConstantValueOpcodes.set(Const.ICONST_2);
defensiveConstantValueOpcodes.set(Const.ICONST_3);
defensiveConstantValueOpcodes.set(Const.ICONST_4);
defensiveConstantValueOpcodes.set(Const.ICONST_5);
defensiveConstantValueOpcodes.set(Const.LCONST_0);
defensiveConstantValueOpcodes.set(Const.LCONST_1);
defensiveConstantValueOpcodes.set(Const.LDC);
defensiveConstantValueOpcodes.set(Const.LDC_W);
defensiveConstantValueOpcodes.set(Const.LDC2_W);
}
private final BugReporter bugReporter;
public FindDeadLocalStores(BugReporter bugReporter) {
this.bugReporter = bugReporter;
if (DEBUG) {
System.out.println("Debugging FindDeadLocalStores detector");
}
}
private boolean prescreen(ClassContext classContext, Method method) {
return true;
}
@Override
public void visitClassContext(ClassContext classContext) {
JavaClass javaClass = classContext.getJavaClass();
Method[] methodList = javaClass.getMethods();
for (Method method : methodList) {
MethodGen methodGen = classContext.getMethodGen(method);
if (methodGen == null) {
continue;
}
if (!prescreen(classContext, method)) {
continue;
}
try {
analyzeMethod(classContext, method);
} catch (DataflowAnalysisException e) {
bugReporter.logError("Error analyzing " + method.toString(), e);
} catch (CFGBuilderException e) {
bugReporter.logError("Error analyzing " + method.toString(), e);
}
}
}
private void analyzeMethod(ClassContext classContext, Method method) throws DataflowAnalysisException, CFGBuilderException {
if (BCELUtil.isSynthetic(method) || (method.getAccessFlags() & Const.ACC_BRIDGE) == Const.ACC_BRIDGE) {
return;
}
if (method.getName().startsWith("$$_hibernate_")) {
return;
}
if (DEBUG) {
System.out.println(" Analyzing method " + classContext.getJavaClass().getClassName() + "." + method.getName());
}
JavaClass javaClass = classContext.getJavaClass();
BitSet linesMentionedMultipleTimes = classContext.linesMentionedMultipleTimes(method);
BugAccumulator accumulator = new BugAccumulator(bugReporter);
Dataflow llsaDataflow = classContext.getLiveLocalStoreDataflow(method);
int numLocals = method.getCode().getMaxLocals();
int[] localStoreCount = new int[numLocals];
int[] localLoadCount = new int[numLocals];
int[] localIncrementCount = new int[numLocals];
MethodGen methodGen = classContext.getMethodGen(method);
ConstantPoolGen cpg = classContext.getConstantPoolGen();
CFG cfg = classContext.getCFG(method);
if (cfg.isFlagSet(CFG.FOUND_INEXACT_UNCONDITIONAL_THROWERS)) {
return;
}
BitSet liveStoreSetAtEntry = llsaDataflow.getAnalysis().getResultFact(cfg.getEntry());
BitSet complainedAbout = new BitSet();
TypeDataflow typeDataflow = classContext.getTypeDataflow(method);
// Get number of locals that are parameters.
int localsThatAreParameters = PreorderVisitor.getNumberArguments(method.getSignature());
if (!method.isStatic()) {
localsThatAreParameters++;
}
// Scan method to determine number of loads, stores, and increments
// of local variables.
countLocalStoresLoadsAndIncrements(localStoreCount, localLoadCount, localIncrementCount, cfg);
for (int i = 0; i < localsThatAreParameters; i++) {
localStoreCount[i]++;
}
// For each source line, keep track of # times
// the line was a live store. This can eliminate false positives
// due to inlining of finally blocks.
BitSet liveStoreSourceLineSet = new BitSet();
// Keep track of the switches so we can ignore the dead stores corresponding to type switches
SwitchHandler switchHandler = new SwitchHandler();
// Scan method for
// - dead stores
// - stores to parameters that are dead upon entry to the method
for (Iterator i = cfg.locationIterator(); i.hasNext();) {
Location location = i.next();
BugInstance pendingBugReportAboutOverwrittenParameter = null;
try {
WarningPropertySet propertySet = new WarningPropertySet<>();
InstructionHandle handle = location.getHandle();
int pc = handle.getPosition();
if (handle.getInstruction() instanceof INVOKEDYNAMIC) {
INVOKEDYNAMIC invokeDynamicInstruction = (INVOKEDYNAMIC) handle.getInstruction();
String invokeMethodName = invokeDynamicInstruction.getMethodName(cpg);
switchHandler.sawInvokeDynamic(pc, invokeMethodName);
continue;
} else if (handle.getInstruction() instanceof Select) {
Select switchInstruction = (Select) handle.getInstruction();
int[] indices = switchInstruction.getIndices();
switchHandler.enterSwitch(switchInstruction.getOpcode(),
pc,
indices,
0, // Not sure how to get the default offset from BCEL but it doesn't matter here
false); // It shouldn't matter here if the switch was exhaustive or not
}
// Skip any instruction which is not a store
if (!isStore(location)) {
continue;
}
if (switchHandler.isTypeSwitchCaseLoad(location)) {
continue;
}
// Heuristic: exception handler blocks often contain
// dead stores generated by the compiler.
if (location.getBasicBlock().isExceptionHandler()) {
propertySet.addProperty(DeadLocalStoreProperty.EXCEPTION_HANDLER);
}
IndexedInstruction ins = (IndexedInstruction) location.getHandle().getInstruction();
int local = ins.getIndex();
// Get live stores at this instruction.
// Note that the analysis also computes which stores were
// killed by a subsequent unconditional store.
BitSet liveStoreSet = llsaDataflow.getAnalysis().getFactAtLocation(location);
// Is store alive?
boolean storeLive = llsaDataflow.getAnalysis().isStoreAlive(liveStoreSet, local);
LocalVariableAnnotation lvAnnotation = LocalVariableAnnotation.getLocalVariableAnnotation(method, location, ins);
String sourceFileName = javaClass.getSourceFileName();
if (LocalVariableAnnotation.UNKNOWN_NAME.equals(lvAnnotation.getName())) {
if (sourceFileName.endsWith(".groovy")) {
continue;
}
}
SourceLineAnnotation sourceLineAnnotation = SourceLineAnnotation.fromVisitedInstruction(classContext, methodGen,
sourceFileName, location.getHandle());
if (DEBUG) {
System.out.println(" Store at " + sourceLineAnnotation.getStartLine() + "@"
+ location.getHandle().getPosition() + " is " + (storeLive ? "live" : "dead"));
System.out.println("Previous is: " + location.getHandle().getPrev());
}
// Note source lines of live stores.
if (storeLive && sourceLineAnnotation.getStartLine() > 0) {
liveStoreSourceLineSet.set(sourceLineAnnotation.getStartLine());
}
String lvName = lvAnnotation.getName();
if (lvName.charAt(0) == '$' || lvName.charAt(0) == '_') {
propertySet.addProperty(DeadLocalStoreProperty.SYNTHETIC_NAME);
}
if (EXCLUDED_LOCALS.contains(lvName)) {
continue;
}
propertySet.setProperty(DeadLocalStoreProperty.LOCAL_NAME, lvName);
boolean isParameter = local < localsThatAreParameters;
if (isParameter) {
propertySet.addProperty(DeadLocalStoreProperty.IS_PARAMETER);
}
Field shadowedField = null;
for (Field f : javaClass.getFields()) {
if (f.getName().equals(lvName) && f.isStatic() == method.isStatic()) {
shadowedField = f;
propertySet.addProperty(DeadLocalStoreProperty.SHADOWS_FIELD);
break;
}
}
// Is this a store to a parameter which was dead on entry to the
// method?
boolean parameterThatIsDeadAtEntry = isParameter
&& !llsaDataflow.getAnalysis().isStoreAlive(liveStoreSetAtEntry, local);
if (parameterThatIsDeadAtEntry && !complainedAbout.get(local)) {
int priority = storeLive ? LOW_PRIORITY : NORMAL_PRIORITY;
if (shadowedField != null) {
priority--;
}
pendingBugReportAboutOverwrittenParameter = new BugInstance(this, "IP_PARAMETER_IS_DEAD_BUT_OVERWRITTEN",
priority).addClassAndMethod(methodGen, sourceFileName).add(lvAnnotation);
if (shadowedField != null) {
pendingBugReportAboutOverwrittenParameter.addField(
FieldAnnotation.fromBCELField(classContext.getJavaClass(), shadowedField)).describe(
FieldAnnotation.DID_YOU_MEAN_ROLE);
}
pendingBugReportAboutOverwrittenParameter.addSourceLine(classContext, methodGen, sourceFileName,
location.getHandle());
complainedAbout.set(local);
}
if (storeLive) {
continue;
}
TypeFrame typeFrame = typeDataflow.getAnalysis().getFactAtLocation(location);
Type typeOfValue = null;
if (typeFrame.isValid() && typeFrame.getStackDepth() > 0) {
typeOfValue = typeFrame.getTopValue();
}
boolean storeOfNull = false;
InstructionHandle prevInsHandle = location.getHandle().getPrev();
if (prevInsHandle != null) {
Instruction prevIns = prevInsHandle.getInstruction();
boolean foundDeadClassInitialization = false;
String initializationOf = null;
if (prevIns instanceof ConstantPushInstruction) {
continue; // not an interesting dead store
} else if (prevIns instanceof GETSTATIC) {
GETSTATIC getStatic = (GETSTATIC) prevIns;
foundDeadClassInitialization = getStatic.getFieldName(cpg).startsWith("class$")
&& "Ljava/lang/Class;".equals(getStatic.getSignature(cpg));
for (Iterator j = cfg.locationIterator(); j.hasNext();) {
Location location2 = j.next();
if (location2.getHandle().getPosition() + 15 == location.getHandle().getPosition()) {
Instruction instruction2 = location2.getHandle().getInstruction();
if (instruction2 instanceof LDC) {
Object value = ((LDC) instruction2).getValue(methodGen.getConstantPool());
if (value instanceof String) {
String n = (String) value;
if (n.length() > 0) {
initializationOf = ClassName.toSignature(n);
}
}
}
}
}
} else if (prevIns instanceof LDC) {
LDC ldc = (LDC) prevIns;
Type t = ldc.getType(methodGen.getConstantPool());
if ("Ljava/lang/Class;".equals(t.getSignature())) {
Object value = ldc.getValue(methodGen.getConstantPool());
if (value instanceof ConstantClass) {
ConstantClass v = (ConstantClass) value;
initializationOf = ClassName.toSignature(v.getBytes(javaClass.getConstantPool()));
foundDeadClassInitialization = true;
} else if (value instanceof ObjectType) {
ObjectType v = (ObjectType) value;
initializationOf = ClassName.toSignature(v.getClassName());
foundDeadClassInitialization = true;
} else {
AnalysisContext.logError("LDC loaded " + value + "at " + location.getHandle().getPosition() + " in " + classContext
.getFullyQualifiedMethodName(method));
}
} else {
continue; // not an interesting DLS
}
} else if (prevIns instanceof DUP2) {
// Check for the case where, due to the bytecode
// compiler, a long is needlessly stored just
// after we've DUP2'ed the stack and just
// before we return
Instruction cur = location.getHandle().getInstruction();
Instruction nxt = location.getHandle().getNext().getInstruction();
if (cur instanceof LSTORE && nxt instanceof LRETURN) {
continue; // not an interesting DLS
}
}
if (foundDeadClassInitialization) {
if ("org.apache.axis.client.Stub".equals(classContext.getJavaClass().getSuperclassName())) {
continue;
}
BugInstance bugInstance = new BugInstance(this, "DLS_DEAD_STORE_OF_CLASS_LITERAL",
Priorities.NORMAL_PRIORITY).addClassAndMethod(methodGen, sourceFileName).add(lvAnnotation)
.addType(initializationOf);
accumulator.accumulateBug(bugInstance, sourceLineAnnotation);
continue;
}
if (prevIns instanceof LDC) {
propertySet.addProperty(DeadLocalStoreProperty.STORE_OF_CONSTANT);
} else if (prevIns instanceof ACONST_NULL) {
storeOfNull = true;
propertySet.addProperty(DeadLocalStoreProperty.STORE_OF_NULL);
}
}
if (typeOfValue instanceof BasicType || Type.STRING.equals(typeOfValue)) {
propertySet.addProperty(DeadLocalStoreProperty.BASE_VALUE);
}
// Ignore assignments that were killed by a subsequent
// assignment.
boolean killedBySubsequentStore = llsaDataflow.getAnalysis().killedByStore(liveStoreSet, local);
if (killedBySubsequentStore) {
if (propertySet.containsProperty(DeadLocalStoreProperty.STORE_OF_NULL)
|| propertySet.containsProperty(DeadLocalStoreProperty.STORE_OF_CONSTANT)) {
continue;
}
propertySet.addProperty(DeadLocalStoreProperty.KILLED_BY_SUBSEQUENT_STORE);
}
// Ignore dead assignments of null and 0.
// These often indicate defensive programming.
InstructionHandle prev = location.getBasicBlock().getPredecessorOf(location.getHandle());
// int prevOpCode = -1;
if (prev != null) {
if (defensiveConstantValueOpcodes.get(prev.getInstruction().getOpcode())) {
propertySet.addProperty(DeadLocalStoreProperty.DEFENSIVE_CONSTANT_OPCODE);
// prevOpCode = prev.getInstruction().getOpcode();
}
if (prev.getInstruction() instanceof GETFIELD) {
InstructionHandle prev2 = prev.getPrev();
if (prev2 != null && prev2.getInstruction() instanceof ALOAD) {
propertySet.addProperty(DeadLocalStoreProperty.CACHING_VALUE);
}
}
if (prev.getInstruction() instanceof LoadInstruction) {
propertySet.addProperty(DeadLocalStoreProperty.COPY_VALUE);
}
if (prev.getInstruction() instanceof InvokeInstruction) {
propertySet.addProperty(DeadLocalStoreProperty.METHOD_RESULT);
}
}
boolean deadObjectStore = false;
if (ins instanceof IINC) {
// special handling of IINC
if ("main".equals(method.getName()) && method.isStatic()
&& "([Ljava/lang/String;)V".equals(method.getSignature())) {
propertySet.addProperty(DeadLocalStoreProperty.DEAD_INCREMENT_IN_MAIN);
}
InstructionHandle next = location.getHandle().getNext();
if (next != null && next.getInstruction() instanceof IRETURN) {
propertySet.addProperty(DeadLocalStoreProperty.DEAD_INCREMENT_IN_RETURN);
} else {
propertySet.addProperty(DeadLocalStoreProperty.DEAD_INCREMENT);
}
if (localIncrementCount[local] == 1) {
propertySet.addProperty(DeadLocalStoreProperty.SINGLE_DEAD_INCREMENT);
} else {
propertySet.removeProperty(DeadLocalStoreProperty.IS_PARAMETER);
}
} else if (ins instanceof ASTORE && prev != null) {
// Look for objects created but never used
Instruction prevIns = prev.getInstruction();
if ((prevIns instanceof INVOKESPECIAL && Const.CONSTRUCTOR_NAME.equals(((INVOKESPECIAL) prevIns).getMethodName(methodGen
.getConstantPool())))
|| prevIns instanceof ANEWARRAY
|| prevIns instanceof NEWARRAY
|| prevIns instanceof MULTIANEWARRAY) {
deadObjectStore = true;
} else if (prevIns instanceof DUP) {
propertySet.addProperty(DeadLocalStoreProperty.DUP_THEN_STORE);
}
}
if (deadObjectStore) {
propertySet.addProperty(DeadLocalStoreProperty.DEAD_OBJECT_STORE);
} else if (!killedBySubsequentStore && localStoreCount[local] == 2 && localLoadCount[local] > 0) {
// TODO: why is this significant?
propertySet.addProperty(DeadLocalStoreProperty.TWO_STORES_MULTIPLE_LOADS);
} else if (!parameterThatIsDeadAtEntry && localStoreCount[local] == 1 && localLoadCount[local] == 0
&& propertySet.containsProperty(DeadLocalStoreProperty.DEFENSIVE_CONSTANT_OPCODE)) {
// might be final local constant
propertySet.addProperty(DeadLocalStoreProperty.SINGLE_STORE);
} else if (!parameterThatIsDeadAtEntry && !propertySet.containsProperty(DeadLocalStoreProperty.SHADOWS_FIELD)
&& localLoadCount[local] == 0) {
// TODO: why is this significant?
propertySet.addProperty(DeadLocalStoreProperty.NO_LOADS);
}
if (!storeOfNull && typeOfValue != null
&& !propertySet.containsProperty(DeadLocalStoreProperty.EXCEPTION_HANDLER)) {
String signatureOfValue = typeOfValue.getSignature();
if ((signatureOfValue.startsWith("Ljava/sql/") || signatureOfValue.startsWith("Ljavax/sql/"))
&& !signatureOfValue.endsWith("Exception")) {
propertySet.addProperty(DeadLocalStoreProperty.STORE_OF_DATABASE_VALUE);
}
}
if (parameterThatIsDeadAtEntry) {
propertySet.addProperty(DeadLocalStoreProperty.PARAM_DEAD_ON_ENTRY);
if (pendingBugReportAboutOverwrittenParameter != null) {
pendingBugReportAboutOverwrittenParameter.setPriority(Priorities.HIGH_PRIORITY);
}
}
if (localStoreCount[local] > 3) {
propertySet.addProperty(DeadLocalStoreProperty.MANY_STORES);
}
int occurrences = cfg.getLocationsContainingInstructionWithOffset(pc).size();
if (occurrences > 2 || sourceLineAnnotation.getStartLine() > 0
&& linesMentionedMultipleTimes.get(sourceLineAnnotation.getStartLine())) {
propertySet.addProperty(DeadLocalStoreProperty.CLONED_STORE);
}
String sourceFile = javaClass.getSourceFileName();
if (Subtypes2.isJSP(javaClass)) {
propertySet.addProperty(DeadLocalStoreProperty.IN_JSP_PAGE);
} else if (BCELUtil.isSynthetic(javaClass) || sourceFile != null && !sourceFile.endsWith(".java")) {
if (sourceFile != null && sourceFile.endsWith(".gxp") && (lvName.startsWith("gxp$") || lvName.startsWith("gxp_"))) {
continue;
}
propertySet.addProperty(DeadLocalStoreProperty.NOT_JAVA);
}
// Report the warning
String bugPattern;
if (storeOfNull) {
bugPattern = "DLS_DEAD_LOCAL_STORE_OF_NULL";
} else if (shadowedField != null) {
bugPattern = "DLS_DEAD_LOCAL_STORE_SHADOWS_FIELD";
} else if (propertySet.containsProperty(DeadLocalStoreProperty.DEAD_INCREMENT_IN_RETURN)) {
bugPattern = "DLS_DEAD_LOCAL_INCREMENT_IN_RETURN";
} else {
bugPattern = "DLS_DEAD_LOCAL_STORE";
}
BugInstance bugInstance = new BugInstance(this, bugPattern, NORMAL_PRIORITY).addClassAndMethod(methodGen,
sourceFileName).add(lvAnnotation);
if (shadowedField != null) {
bugInstance.addField(FieldAnnotation.fromBCELField(classContext.getJavaClass(), shadowedField)).describe(
FieldAnnotation.DID_YOU_MEAN_ROLE);
}
// If in relaxed reporting mode, encode heuristic
// information.
if (FindBugsAnalysisFeatures.isRelaxedMode()) {
// Add general-purpose warning properties
WarningPropertyUtil.addPropertiesForDataMining(propertySet, classContext, method, location);
}
// Turn all warning properties into BugProperties
propertySet.decorateBugInstance(bugInstance);
if (DEBUG) {
System.out.println(sourceFileName + " : " + methodGen.getName());
System.out.println("priority: " + bugInstance.getPriority());
System.out.println("Reporting " + bugInstance);
System.out.println(propertySet);
}
accumulator.accumulateBug(bugInstance, sourceLineAnnotation);
} finally {
if (pendingBugReportAboutOverwrittenParameter != null) {
bugReporter.reportBug(pendingBugReportAboutOverwrittenParameter);
}
}
}
suppressWarningsIfOneLiveStoreOnLine(accumulator, liveStoreSourceLineSet);
accumulator.reportAccumulatedBugs();
}
/**
* If feature is enabled, suppress warnings where there is at least one live
* store on the line where the warning would be reported.
*
* @param accumulator
* BugAccumulator containing warnings for method
* @param liveStoreSourceLineSet
* bitset of lines where at least one live store was seen
*/
private void suppressWarningsIfOneLiveStoreOnLine(BugAccumulator accumulator, BitSet liveStoreSourceLineSet) {
if (!SUPPRESS_IF_AT_LEAST_ONE_LIVE_STORE_ON_LINE) {
return;
}
// Eliminate any accumulated warnings for instructions
// that (due to inlining) *can* be live stores.
entryLoop: for (Iterator i = accumulator.uniqueBugs().iterator(); i.hasNext();) {
for (SourceLineAnnotation annotation : accumulator.locations(i.next())) {
if (liveStoreSourceLineSet.get(annotation.getStartLine())) {
// This instruction can be a live store; don't report
// it as a warning.
i.remove();
continue entryLoop;
}
}
}
}
/**
* Count stores, loads, and increments of local variables in method whose
* CFG is given.
*
* @param localStoreCount
* counts of local stores (indexed by local)
* @param localLoadCount
* counts of local loads (indexed by local)
* @param localIncrementCount
* counts of local increments (indexed by local)
* @param cfg
* control flow graph (CFG) of method
*/
private void countLocalStoresLoadsAndIncrements(int[] localStoreCount, int[] localLoadCount, int[] localIncrementCount,
CFG cfg) {
for (Iterator i = cfg.locationIterator(); i.hasNext();) {
Location location = i.next();
if (location.getBasicBlock().isExceptionHandler()) {
continue;
}
boolean isStore = isStore(location);
boolean isLoad = isLoad(location);
if (!isStore && !isLoad) {
continue;
}
IndexedInstruction ins = (IndexedInstruction) location.getHandle().getInstruction();
int local = ins.getIndex();
if (ins instanceof IINC) {
localStoreCount[local]++;
localLoadCount[local]++;
localIncrementCount[local]++;
} else if (isStore) {
localStoreCount[local]++;
} else {
localLoadCount[local]++;
}
}
}
/**
* Get the name of given local variable (if possible) and store it in the
* HeuristicPropertySet.
*
* @param lvt
* the LocalVariableTable
* @param local
* index of the local
* @param pc
* program counter value of the instruction
*
private void checkLocalVariableName(LocalVariableTable lvt, int local, int pc,
WarningPropertySet propertySet) {
if (lvt != null) {
LocalVariable lv = lvt.getLocalVariable(local, pc);
if (lv != null) {
String localName = lv.getName();
propertySet.setProperty(DeadLocalStoreProperty.LOCAL_NAME, localName);
}
}
}*/
/**
* Is instruction at given location a store?
*
* @param location
* the location
* @return true if instruction at given location is a store, false if not
*/
private boolean isStore(Location location) {
Instruction ins = location.getHandle().getInstruction();
return (ins instanceof StoreInstruction) || (ins instanceof IINC);
}
/**
* Is instruction at given location a load?
*
* @param location
* the location
* @return true if instruction at given location is a load, false if not
*/
private boolean isLoad(Location location) {
Instruction ins = location.getHandle().getInstruction();
return (ins instanceof LoadInstruction) || (ins instanceof IINC);
}
@Override
public void report() {
}
}