/*
* Bytecode Analysis Framework
* 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.ba;
import java.util.BitSet;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
import java.util.regex.Pattern;
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.INVOKEINTERFACE;
import org.apache.bcel.generic.INVOKESTATIC;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionHandle;
import org.apache.bcel.generic.InvokeInstruction;
import org.apache.bcel.generic.MethodGen;
import edu.umd.cs.findbugs.SystemProperties;
import edu.umd.cs.findbugs.ba.type.TypeDataflow;
import edu.umd.cs.findbugs.ba.type.TypeFrame;
import edu.umd.cs.findbugs.classfile.CheckedAnalysisException;
import edu.umd.cs.findbugs.classfile.Global;
public class PruneUnconditionalExceptionThrowerEdges implements EdgeTypes {
private static final boolean DEBUG = SystemProperties.getBoolean("cfg.prune.throwers.debug");
private static final boolean DEBUG_DIFFERENCES = SystemProperties.getBoolean("cfg.prune.throwers.differences.debug");
private static final String UNCONDITIONAL_THROWER_METHOD_NAMES = SystemProperties.getProperty(
"findbugs.unconditionalThrower", " ").replace(',', '|');
private final MethodGen methodGen;
private final CFG cfg;
private final ConstantPoolGen cpg;
private final TypeDataflow typeDataflow;
private final AnalysisContext analysisContext;
private boolean cfgModified;
private static final Pattern unconditionalThrowerPattern;
private static final BitSet RETURN_OPCODE_SET = new BitSet();
static {
RETURN_OPCODE_SET.set(Constants.ARETURN);
RETURN_OPCODE_SET.set(Constants.IRETURN);
RETURN_OPCODE_SET.set(Constants.LRETURN);
RETURN_OPCODE_SET.set(Constants.DRETURN);
RETURN_OPCODE_SET.set(Constants.FRETURN);
RETURN_OPCODE_SET.set(Constants.RETURN);
Pattern p;
try {
p = Pattern.compile(UNCONDITIONAL_THROWER_METHOD_NAMES);
if (DEBUG) {
System.out.println("Pattern is '" + p + "'");
System.out.println(p.matcher("showInvalidPage").matches());
}
} catch (RuntimeException e) {
AnalysisContext.logError("Error compiling unconditional thrower pattern " + UNCONDITIONAL_THROWER_METHOD_NAMES, e);
p = Pattern.compile(" ");
}
unconditionalThrowerPattern = p;
}
public PruneUnconditionalExceptionThrowerEdges(/* ClassContext classContext, */JavaClass javaClass, Method method,
MethodGen methodGen, CFG cfg, ConstantPoolGen cpg, TypeDataflow typeDataflow, AnalysisContext analysisContext) {
// this.classContext = classContext;
this.methodGen = methodGen;
this.cfg = cfg;
this.cpg = cpg;
this.typeDataflow = typeDataflow;
this.analysisContext = analysisContext;
}
public void execute() throws DataflowAnalysisException {
AnalysisContext currentAnalysisContext = AnalysisContext.currentAnalysisContext();
if (currentAnalysisContext.getBoolProperty(AnalysisFeatures.CONSERVE_SPACE)) {
throw new IllegalStateException("This should not happen");
}
boolean foundInexact = false;
Set<Edge> deletedEdgeSet = new HashSet<Edge>();
// TypeDataflow typeDataflow = classContext.getTypeDataflow(method);
if (DEBUG) {
System.out.println("PruneUnconditionalExceptionThrowerEdges: examining "
+ SignatureConverter.convertMethodSignature(methodGen));
}
for (Iterator<BasicBlock> i = cfg.blockIterator(); i.hasNext();) {
BasicBlock basicBlock = i.next();
if (!basicBlock.isExceptionThrower()) {
continue;
}
InstructionHandle instructionHandle = basicBlock.getExceptionThrower();
Instruction exceptionThrower = instructionHandle.getInstruction();
if (!(exceptionThrower instanceof InvokeInstruction)) {
continue;
}
InvokeInstruction inv = (InvokeInstruction) exceptionThrower;
boolean foundThrower = false;
boolean foundNonThrower = false;
boolean isExact = true;
XMethod primaryXMethod = XFactory.createXMethod(inv, cpg);
final String methodName = primaryXMethod.getName();
final boolean matches = unconditionalThrowerPattern.matcher(methodName).matches();
if (DEBUG) {
System.out.println("Checking '" + methodName + "' is " + matches);
}
if (matches) {
if (DEBUG) {
System.out.println("\tmatched for " + instructionHandle + " : " + primaryXMethod);
}
foundThrower = true;
} else if (inv instanceof INVOKEINTERFACE) {
continue;
} else if (inv instanceof INVOKESTATIC) {
foundThrower = isUnconditionalThrower(primaryXMethod);
} else {
String className = inv.getClassName(cpg);
if (DEBUG) {
System.out.println("\tlooking up method for " + instructionHandle + " : " + primaryXMethod);
}
Location loc = new Location(instructionHandle, basicBlock);
TypeFrame typeFrame = typeDataflow.getFactAtLocation(loc);
// if (primaryXMethod.isAbstract()) continue;
Set<XMethod> targetSet = null;
try {
if (className.startsWith("[")) {
continue;
}
String methodSig = inv.getSignature(cpg);
if (!methodSig.endsWith("V") && !methodSig.endsWith("Exception;")
&& !methodSig.endsWith("Error;") && !methodSig.endsWith(")Ljava/lang/Object;")) {
continue;
}
targetSet = Hierarchy2.resolveMethodCallTargets(inv, typeFrame, cpg);
for (XMethod xMethod : targetSet) {
if (DEBUG) {
System.out.println("\tFound " + xMethod);
}
// Ignore abstract and native methods
if (!(xMethod.isFinal() || xMethod.isStatic() || xMethod.isPrivate())) {
try {
isExact = false;
XClass xClass = Global.getAnalysisCache().getClassAnalysis(XClass.class,
xMethod.getClassDescriptor());
if (xClass.isAbstract()) {
continue;
}
} catch (CheckedAnalysisException e) {
AnalysisContext.logError("Unable to resolve class for " + xMethod, e);
}
}
boolean isUnconditionalThrower = isUnconditionalThrower(xMethod);
if (isUnconditionalThrower) {
foundThrower = true;
if (DEBUG) {
System.out.println("Found thrower");
}
} else {
foundNonThrower = true;
if (DEBUG) {
System.out.println("Found non thrower");
}
}
}
} catch (ClassNotFoundException e) {
analysisContext.getLookupFailureCallback().reportMissingClass(e);
}
}
boolean newResult = foundThrower && !foundNonThrower;
if (newResult) {
if (!isExact) {
foundInexact = true;
}
// Method always throws an unhandled exception
// Remove the normal control flow edge from the CFG.
Edge fallThrough = cfg.getOutgoingEdgeWithType(basicBlock, FALL_THROUGH_EDGE);
if (fallThrough != null) {
if (DEBUG) {
System.out.println("\tREMOVING normal return for: " + primaryXMethod);
}
deletedEdgeSet.add(fallThrough);
}
}
}
if (!deletedEdgeSet.isEmpty()) {
cfgModified = true;
if (foundInexact) {
cfg.setFlag(CFG.FOUND_INEXACT_UNCONDITIONAL_THROWERS);
}
// Remove all edges marked for deletion
for (Edge edge : deletedEdgeSet) {
cfg.removeEdge(edge);
}
}
}
private boolean isUnconditionalThrower(XMethod xMethod) {
return xMethod.isUnconditionalThrower() && !xMethod.isUnsupported() && !xMethod.isSynthetic();
}
/**
* @param xMethod
* @param javaClass
* @param method
* @return true if method unconditionally throws
* @deprecated Use {@link #doesMethodUnconditionallyThrowException(XMethod)}
* instead
*/
@Deprecated
static public Boolean doesMethodUnconditionallyThrowException(XMethod xMethod, JavaClass javaClass, Method method) {
return doesMethodUnconditionallyThrowException(xMethod);
}
/**
* @param xMethod
* @return true if method unconditionally throws
*/
static public boolean doesMethodUnconditionallyThrowException(XMethod xMethod) {
return xMethod.isUnconditionalThrower();
}
/**
* Return whether or not the CFG was modified.
*
* @return true if CFG was modified, false otherwise
*/
public boolean wasCFGModified() {
return cfgModified;
}
}