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A Java Optimization Framework
package soot.dava.toolkits.base.AST.structuredAnalysis;
/*-
* #%L
* Soot - a J*va Optimization Framework
* %%
* Copyright (C) 2006 Nomair A. Naeem ([email protected])
* %%
* This program 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 program 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 General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* .
* #L%
*/
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import soot.Local;
import soot.SootField;
import soot.Value;
import soot.dava.DavaFlowAnalysisException;
import soot.dava.internal.AST.ASTUnaryBinaryCondition;
import soot.jimple.DefinitionStmt;
import soot.jimple.FieldRef;
import soot.jimple.Stmt;
//import soot.dava.internal.javaRep.*;
/*
* The analysis stores all defs of Locals/SootField. The user can then ask whether a local or SootField
isMustInitialized or isMayInitialized
*
MustInitialize/MayInitialize
Step 1:
Set of initialized locals/SootField
Step 2:
A local or SootField is MUST initialized at a program point p if on all paths from the start to this
point the local or SootField is assigned a value.
Similarly a local or SootField is MAY initialized at a program point p if there is a path from the start
to this point on wich the local or SootField is assigned
Step 3:
Forward Analysis
Step 4:
Intersection/Union
Step 5:
x = expr
kill = {}
if x is a local or SootField, gen(x) = {x}
Step 6:
out(start) = {}
newInitialFlow: No copies are available. an empty flow set
remember new InitialFlow is ONLY used for input to catchBodies
*
*
*/
public class MustMayInitialize extends StructuredAnalysis {
HashMap mapping;
DavaFlowSet finalResult;
public static final int MUST = 0;
public static final int MAY = 1;
int MUSTMAY;
public MustMayInitialize(Object analyze, int MUSTorMAY) {
super();
mapping = new HashMap();
MUSTMAY = MUSTorMAY;
// System.out.println("MustOrMay value is"+MUSTorMAY);
setMergeType();
// the input to the process method is an empty DavaFlow Set meaning
// out(start) ={} (no var initialized)
finalResult = (DavaFlowSet) process(analyze, new DavaFlowSet());
// finalResult contains the flowSet of having processed the whole of the
// method
}
public DavaFlowSet emptyFlowSet() {
return new DavaFlowSet();
}
public void setMergeType() {
// System.out.println("here"+MUSTMAY);
if (MUSTMAY == MUST) {
MERGETYPE = INTERSECTION;
// System.out.println("MERGETYPE set to intersection");
} else if (MUSTMAY == MAY) {
MERGETYPE = UNION;
// System.out.println("MERGETYPE set to union");
} else {
throw new DavaFlowAnalysisException("Only allowed 0 or 1 for MUST or MAY values");
}
}
/*
* newInitialFlow set is used only for start of catch bodies and here we assume that no var is ever being initialized
*/
@Override
public DavaFlowSet newInitialFlow() {
return new DavaFlowSet();
}
@Override
public DavaFlowSet cloneFlowSet(DavaFlowSet flowSet) {
return ((DavaFlowSet) flowSet).clone();
}
/*
* By construction conditions never have assignment statements. Hence processing a condition has no effect on this analysis
*/
@Override
public DavaFlowSet processUnaryBinaryCondition(ASTUnaryBinaryCondition cond, DavaFlowSet input) {
return input;
}
/*
* By construction the synchronized Local is a Value and can definetly not have an assignment stmt Processing a synch local
* has no effect on this analysis
*/
@Override
public DavaFlowSet processSynchronizedLocal(Local local, DavaFlowSet input) {
return input;
}
/*
* The switch key is stored as a value and hence can never have an assignment stmt Processing the switch key has no effect
* on the analysis
*/
@Override
public DavaFlowSet processSwitchKey(Value key, DavaFlowSet input) {
return input;
}
/*
* This method internally invoked by the process method decides which Statement specialized method to call
*/
@Override
public DavaFlowSet processStatement(Stmt s, DavaFlowSet inSet) {
/*
* If this path will not be taken return no path straightaway
*/
if (inSet == NOPATH) {
return inSet;
}
if (s instanceof DefinitionStmt) {
DavaFlowSet toReturn = (DavaFlowSet) cloneFlowSet(inSet);
// x = expr;
Value leftOp = ((DefinitionStmt) s).getLeftOp();
SootField field = null;
if (leftOp instanceof Local) {
toReturn.add(leftOp);
/*
* Gather more information just in case someone might need the def points
*/
Object temp = mapping.get(leftOp);
List defs;
if (temp == null) {
// first definition
defs = new ArrayList();
} else {
defs = (ArrayList) temp;
}
defs.add(s);
mapping.put(leftOp, defs);
} else if (leftOp instanceof FieldRef) {
field = ((FieldRef) leftOp).getField();
toReturn.add(field);
/*
* Gather more information just in case someone might need the def points
*/
Object temp = mapping.get(field);
List defs;
if (temp == null) {
// first definition
defs = new ArrayList();
} else {
defs = (ArrayList) temp;
}
defs.add(s);
mapping.put(field, defs);
}
return toReturn;
}
return inSet;
}
public boolean isMayInitialized(SootField field) {
if (MUSTMAY == MAY) {
Object temp = mapping.get(field);
if (temp == null) {
return false;
} else {
List list = (List) temp;
if (list.size() == 0) {
return false;
} else {
return true;
}
}
} else {
throw new RuntimeException("Cannot invoke isMayInitialized for a MUST analysis");
}
}
public boolean isMayInitialized(Value local) {
if (MUSTMAY == MAY) {
Object temp = mapping.get(local);
if (temp == null) {
return false;
} else {
List list = (List) temp;
if (list.size() == 0) {
return false;
} else {
return true;
}
}
} else {
throw new RuntimeException("Cannot invoke isMayInitialized for a MUST analysis");
}
}
public boolean isMustInitialized(SootField field) {
if (MUSTMAY == MUST) {
if (finalResult.contains(field)) {
return true;
}
return false;
} else {
throw new RuntimeException("Cannot invoke isMustinitialized for a MAY analysis");
}
}
public boolean isMustInitialized(Value local) {
if (MUSTMAY == MUST) {
if (finalResult.contains(local)) {
return true;
}
return false;
} else {
throw new RuntimeException("Cannot invoke isMustinitialized for a MAY analysis");
}
}
/*
* Given a local ask for all def positions Notice this could be null in the case there was no definition
*/
public List getDefs(Value local) {
Object temp = mapping.get(local);
if (temp == null) {
return null;
} else {
return (List) temp;
}
}
/*
* Given a field ask for all def positions Notice this could be null in the case there was no definition
*/
public List getDefs(SootField field) {
Object temp = mapping.get(field);
if (temp == null) {
return null;
} else {
return (List) temp;
}
}
}