/*
* 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.Iterator;
import org.apache.bcel.Constants;
import org.apache.bcel.classfile.Method;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.FieldInstruction;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.ReferenceType;
import org.apache.bcel.generic.Type;
import edu.umd.cs.findbugs.BugReporter;
import edu.umd.cs.findbugs.Detector;
import edu.umd.cs.findbugs.TrainingDetector;
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.DataflowAnalysisException;
import edu.umd.cs.findbugs.ba.Hierarchy;
import edu.umd.cs.findbugs.ba.Location;
import edu.umd.cs.findbugs.ba.XField;
import edu.umd.cs.findbugs.ba.type.FieldStoreType;
import edu.umd.cs.findbugs.ba.type.FieldStoreTypeDatabase;
import edu.umd.cs.findbugs.ba.type.TypeDataflow;
import edu.umd.cs.findbugs.ba.type.TypeFrame;
/**
* Build a database of reference types stored into fields. This can be used in
* the future to improve the precision of type analysis when values are loaded
* from fields.
*
* @author David Hovemeyer
*/
public class TrainFieldStoreTypes implements Detector, TrainingDetector {
private final BugReporter bugReporter;
private final FieldStoreTypeDatabase database;
public TrainFieldStoreTypes(BugReporter bugReporter) {
this.bugReporter = bugReporter;
this.database = new FieldStoreTypeDatabase();
}
@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 (CFGBuilderException e) {
bugReporter.logError("Error compting field store types", e);
} catch (DataflowAnalysisException e) {
bugReporter.logError("Error compting field store types", e);
}
}
}
private void analyzeMethod(ClassContext classContext, Method method) throws CFGBuilderException, DataflowAnalysisException
{
CFG cfg = classContext.getCFG(method);
TypeDataflow typeDataflow = classContext.getTypeDataflow(method);
ConstantPoolGen cpg = classContext.getConstantPoolGen();
for (Iterator<Location> i = cfg.locationIterator(); i.hasNext();) {
Location location = i.next();
Instruction ins = location.getHandle().getInstruction();
short opcode = ins.getOpcode();
// Field store instruction?
if (opcode != Constants.PUTFIELD && opcode != Constants.PUTSTATIC) {
continue;
}
// Check if field type is a reference type
FieldInstruction fins = (FieldInstruction) ins;
Type fieldType = fins.getType(cpg);
if (!(fieldType instanceof ReferenceType)) {
continue;
}
// Find the exact field being stored into
XField xfield = Hierarchy.findXField(fins, cpg);
if (xfield == null) {
continue;
}
// Skip public and protected fields, since it is reasonable to
// assume
// we won't see every store to those fields
if (xfield.isPublic() || xfield.isProtected()) {
continue;
}
// The top value on the stack is the one which will be stored
// into the field
TypeFrame frame = typeDataflow.getFactAtLocation(location);
if (!frame.isValid()) {
continue;
}
Type storeType = frame.getTopValue();
if (!(storeType instanceof ReferenceType)) {
continue;
}
// Get or create the field store type set
FieldStoreType property = database.getProperty(xfield.getFieldDescriptor());
if (property == null) {
property = new FieldStoreType();
database.setProperty(xfield.getFieldDescriptor(), property);
}
// Add the store type to the set
property.addTypeSignature(storeType.getSignature());
}
}
@Override
public void report() {
database.purgeBoringEntries();
AnalysisContext.currentAnalysisContext().storePropertyDatabase(database, FieldStoreTypeDatabase.DEFAULT_FILENAME,
"store type database");
}
}