/*
* 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.ba.heap;
import java.util.HashMap;
import java.util.Map;
import javax.annotation.CheckForNull;
import org.apache.bcel.Constants;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.FieldInstruction;
import org.apache.bcel.generic.Instruction;
import org.apache.bcel.generic.InstructionHandle;
import edu.umd.cs.findbugs.ba.BasicBlock;
import edu.umd.cs.findbugs.ba.DataflowAnalysisException;
import edu.umd.cs.findbugs.ba.DepthFirstSearch;
import edu.umd.cs.findbugs.ba.Edge;
import edu.umd.cs.findbugs.ba.ForwardDataflowAnalysis;
import edu.umd.cs.findbugs.ba.Hierarchy;
import edu.umd.cs.findbugs.ba.XField;
/**
* @author David Hovemeyer
*/
public abstract class FieldSetAnalysis extends ForwardDataflowAnalysis<FieldSet> {
private final ConstantPoolGen cpg;
private final Map<InstructionHandle, XField> instructionToFieldMap;
public FieldSetAnalysis(DepthFirstSearch dfs, ConstantPoolGen cpg) {
super(dfs);
this.cpg = cpg;
this.instructionToFieldMap = new HashMap<InstructionHandle, XField>();
}
public ConstantPoolGen getCPG() {
return cpg;
}
@Override
public void makeFactTop(FieldSet fact) {
fact.setTop();
}
@Override
public boolean isTop(FieldSet fact) {
return fact.isTop();
}
@Override
public void initEntryFact(FieldSet result) throws DataflowAnalysisException {
result.clear();
}
// public void initResultFact(FieldSet result) {
// makeFactTop(result);
// }
@Override
public void meetInto(FieldSet fact, Edge edge, FieldSet result) throws DataflowAnalysisException {
result.mergeWith(fact);
}
@Override
public boolean same(FieldSet fact1, FieldSet fact2) {
return fact1.sameAs(fact2);
}
@Override
public FieldSet createFact() {
return new FieldSet();
}
@Override
public boolean isFactValid(FieldSet fact) {
return fact.isValid();
}
@Override
public void copy(FieldSet source, FieldSet dest) {
dest.copyFrom(source);
}
@Override
public void transferInstruction(InstructionHandle handle, BasicBlock basicBlock, FieldSet fact)
throws DataflowAnalysisException {
if (!isFactValid(fact)) {
return;
}
handleInstruction(handle, basicBlock, fact);
}
private void handleInstruction(InstructionHandle handle, BasicBlock basicBlock, FieldSet fact)
{
Instruction ins = handle.getInstruction();
short opcode = ins.getOpcode();
XField field;
switch (opcode) {
case Constants.GETFIELD:
case Constants.GETSTATIC:
field = lookupField(handle, (FieldInstruction) ins);
if (field != null) {
sawLoad(fact, field);
}
break;
case Constants.PUTFIELD:
case Constants.PUTSTATIC:
field = lookupField(handle, (FieldInstruction) ins);
if (field != null) {
sawStore(fact, field);
}
break;
case Constants.INVOKEINTERFACE:
case Constants.INVOKESPECIAL:
case Constants.INVOKESTATIC:
case Constants.INVOKEVIRTUAL:
// Assume that the called method assigns loads and stores all
// possible fields
fact.setBottom();
break;
default:
break;
}
}
private @CheckForNull XField lookupField(InstructionHandle handle, FieldInstruction fins) {
XField field = instructionToFieldMap.get(handle);
if (field == null) {
field = Hierarchy.findXField(fins, getCPG());
instructionToFieldMap.put(handle, field);
}
return field;
}
protected abstract void sawLoad(FieldSet fact, XField field);
protected abstract void sawStore(FieldSet fact, XField field);
}