/*
* FindBugs - Find Bugs in Java programs
* Copyright (C) 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.Iterator;
import java.util.Set;
import javax.annotation.meta.When;
import org.apache.bcel.Constants;
import org.apache.bcel.classfile.Code;
import org.apache.bcel.classfile.CodeException;
import org.apache.bcel.classfile.ConstantClass;
import org.apache.bcel.classfile.ConstantPool;
import org.apache.bcel.classfile.JavaClass;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.ReferenceType;
import org.apache.bcel.generic.Type;
import edu.umd.cs.findbugs.BugInstance;
import edu.umd.cs.findbugs.Detector;
import edu.umd.cs.findbugs.FindBugsAnalysisFeatures;
import edu.umd.cs.findbugs.LocalVariableAnnotation;
import edu.umd.cs.findbugs.Priorities;
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.ClassContext;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.SignatureParser;
import edu.umd.cs.findbugs.ba.XFactory;
import edu.umd.cs.findbugs.ba.XMethod;
import edu.umd.cs.findbugs.ba.deref.UnconditionalValueDerefDataflow;
import edu.umd.cs.findbugs.ba.deref.UnconditionalValueDerefSet;
import edu.umd.cs.findbugs.ba.interproc.ParameterProperty;
import edu.umd.cs.findbugs.ba.jsr305.TypeQualifierAnnotation;
import edu.umd.cs.findbugs.ba.jsr305.TypeQualifierApplications;
import edu.umd.cs.findbugs.ba.jsr305.TypeQualifierValue;
import edu.umd.cs.findbugs.ba.vna.ValueNumber;
import edu.umd.cs.findbugs.ba.vna.ValueNumberDataflow;
import edu.umd.cs.findbugs.classfile.CheckedAnalysisException;
import edu.umd.cs.findbugs.classfile.ClassDescriptor;
import edu.umd.cs.findbugs.classfile.DescriptorFactory;
/**
* Build database of unconditionally dereferenced parameters.
*
* @author David Hovemeyer
*/
public abstract class BuildUnconditionalParamDerefDatabase implements Detector {
public static final boolean VERBOSE_DEBUG = SystemProperties.getBoolean("fnd.debug.nullarg.verbose");
private static final boolean DEBUG = SystemProperties.getBoolean("fnd.debug.nullarg") || VERBOSE_DEBUG;
public final TypeQualifierValue nonnullTypeQualifierValue;
abstract protected void reportBug(BugInstance bug);
public BuildUnconditionalParamDerefDatabase() {
ClassDescriptor nonnullClassDesc = DescriptorFactory.createClassDescriptor(javax.annotation.Nonnull.class);
this.nonnullTypeQualifierValue = TypeQualifierValue.getValue(nonnullClassDesc, null);
}
public void visitClassContext(ClassContext classContext) {
boolean fullAnalysis = AnalysisContext.currentAnalysisContext().getBoolProperty(
FindBugsAnalysisFeatures.INTERPROCEDURAL_ANALYSIS_OF_REFERENCED_CLASSES);
if (!fullAnalysis && !AnalysisContext.currentAnalysisContext().isApplicationClass(classContext.getJavaClass()))
return;
if (VERBOSE_DEBUG)
System.out.println("Visiting class " + classContext.getJavaClass().getClassName());
for (Method m : classContext.getMethodsInCallOrder())
considerMethod(classContext, m);
}
private void considerMethod(ClassContext classContext, Method method) {
boolean hasReferenceParameters = false;
for (Type argument : method.getArgumentTypes())
if (argument instanceof ReferenceType) {
hasReferenceParameters = true;
}
if (hasReferenceParameters && classContext.getMethodGen(method) != null) {
if (VERBOSE_DEBUG)
System.out.println("Check " + method);
analyzeMethod(classContext, method);
}
}
private void analyzeMethod(ClassContext classContext, Method method) {
JavaClass jclass = classContext.getJavaClass();
XMethod xmethod = XFactory.createXMethod(jclass, method);
try {
CFG cfg = classContext.getCFG(method);
ValueNumberDataflow vnaDataflow = classContext.getValueNumberDataflow(method);
UnconditionalValueDerefDataflow dataflow = classContext.getUnconditionalValueDerefDataflow(method);
SignatureParser parser = new SignatureParser(method.getSignature());
int paramLocalOffset = method.isStatic() ? 0 : 1;
// Build BitSet of params that are unconditionally dereferenced
BitSet unconditionalDerefSet = new BitSet();
UnconditionalValueDerefSet entryFact = dataflow.getResultFact(cfg.getEntry());
Iterator<String> paramIterator = parser.parameterSignatureIterator();
int i = 0;
while (paramIterator.hasNext()) {
String paramSig = paramIterator.next();
ValueNumber paramVN = vnaDataflow.getAnalysis().getEntryValue(paramLocalOffset);
handleParameter: if (entryFact.isUnconditionallyDereferenced(paramVN)) {
TypeQualifierAnnotation directTypeQualifierAnnotation = TypeQualifierApplications
.getDirectTypeQualifierAnnotation(xmethod, i, nonnullTypeQualifierValue);
TypeQualifierAnnotation typeQualifierAnnotation = TypeQualifierApplications
.getEffectiveTypeQualifierAnnotation(xmethod, i, nonnullTypeQualifierValue);
boolean implicitNullCheckForEquals = false;
if (directTypeQualifierAnnotation == null && method.getName().equals("equals")
&& method.getSignature().equals("(Ljava/lang/Object;)Z") && !method.isStatic()) {
implicitNullCheckForEquals = true;
Code code = method.getCode();
ConstantPool cp = jclass.getConstantPool();
byte codeBytes[] = code.getCode();
for (CodeException e : code.getExceptionTable()) {
ConstantClass cl = (ConstantClass) cp.getConstant(e.getCatchType());
int endPC = e.getEndPC();
int startPC = e.getStartPC();
int handlerPC = e.getHandlerPC();
if (startPC == 0 && endPC + 1 == handlerPC && handlerPC == codeBytes.length - 3
&& (codeBytes[handlerPC + 1] & 0xff) == Constants.ICONST_0
&& (codeBytes[handlerPC + 2] & 0xff) == Constants.IRETURN
&& FindNullDeref.catchTypesForNull.contains(cl.getBytes(cp))) {
// equals method body contained in try clause
return;
}
}
typeQualifierAnnotation = TypeQualifierAnnotation.getValue(nonnullTypeQualifierValue, When.MAYBE);
}
if (typeQualifierAnnotation != null && typeQualifierAnnotation.when == When.ALWAYS)
unconditionalDerefSet.set(i);
else if (isCaught(classContext, method, entryFact, paramVN)) {
// ignore
} else if (typeQualifierAnnotation == null)
unconditionalDerefSet.set(i);
else {
int paramLocal = xmethod.isStatic() ? i : i + 1;
int priority = Priorities.NORMAL_PRIORITY;
if (typeQualifierAnnotation.when != When.UNKNOWN)
priority--;
if (xmethod.isStatic() || xmethod.isFinal() || xmethod.isPrivate() || xmethod.getName().equals("<init>")
|| jclass.isFinal())
priority--;
if (directTypeQualifierAnnotation == null)
priority++;
String bugPattern = implicitNullCheckForEquals ? "NP_EQUALS_SHOULD_HANDLE_NULL_ARGUMENT"
: "NP_PARAMETER_MUST_BE_NONNULL_BUT_MARKED_AS_NULLABLE";
reportBug(new BugInstance(this, bugPattern, priority).addClassAndMethod(jclass, method).add(
LocalVariableAnnotation.getParameterLocalVariableAnnotation(method, paramLocal)));
}
}
i++;
if (paramSig.equals("D") || paramSig.equals("J"))
paramLocalOffset += 2;
else
paramLocalOffset += 1;
}
// No need to add properties if there are no unconditionally
// dereferenced params
if (unconditionalDerefSet.isEmpty()) {
if (VERBOSE_DEBUG) {
System.out.println("\tResult is empty");
}
return;
}
if (VERBOSE_DEBUG) {
ClassContext.dumpDataflowInformation(method, cfg, vnaDataflow, classContext.getIsNullValueDataflow(method),
dataflow, classContext.getTypeDataflow(method));
}
ParameterProperty property = new ParameterProperty();
property.setParamsWithProperty(unconditionalDerefSet);
AnalysisContext.currentAnalysisContext().getUnconditionalDerefParamDatabase()
.setProperty(xmethod.getMethodDescriptor(), property);
if (DEBUG) {
System.out.println("Unconditional deref: " + xmethod + "=" + property);
}
} catch (CheckedAnalysisException e) {
AnalysisContext.currentAnalysisContext().getLookupFailureCallback()
.logError("Error analyzing " + xmethod + " for unconditional deref training", e);
}
}
/**
* @param classContext
* @param method
* @param entryFact
* @param paramVN
* @return
*/
public boolean isCaught(ClassContext classContext, Method method, UnconditionalValueDerefSet entryFact, ValueNumber paramVN) {
boolean caught = true;
Set<Location> dereferenceSites
= entryFact.getDerefLocationSet(paramVN);
if (dereferenceSites != null && !dereferenceSites.isEmpty()) {
ConstantPool cp = classContext.getJavaClass().getConstantPool();
for(Location loc : dereferenceSites) {
if (!FindNullDeref.catchesNull(cp, method.getCode(), loc))
caught = false;
}
}
return caught;
}
}