/* Soot - a J*va Optimization Framework
* Copyright (C) 1997-1999 Raja Vallee-Rai
*
* 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.
*/
/*
* Modified by the Sable Research Group and others 1997-1999.
* See the 'credits' file distributed with Soot for the complete list of
* contributors. (Soot is distributed at http://www.sable.mcgill.ca/soot)
*/
package soot.toolkits.scalar;
import soot.options.*;
import soot.*;
import soot.util.*;
import java.util.*;
import soot.jimple.*;
/**
* A BodyTransformer that attemps to minimize the number of local variables used in
* Body by 'reusing' them when possible. Implemented as a singleton.
* For example the code:
*
* for(int i; i < k; i++);
* for(int j; j < k; j++);
*
* would be transformed into:
* for(int i; i < k; i++);
* for(int i; i < k; i++);
*
* assuming to further conflicting uses of i and j.
*
* Note: LocalSplitter is corresponds to the inverse transformation.
*
* @see BodyTransformer
* @see Body
* @see LocalSplitter
*/
public class LocalPacker extends BodyTransformer
{
public LocalPacker( Singletons.Global g ) {}
public static LocalPacker v() { return G.v().soot_toolkits_scalar_LocalPacker(); }
protected void internalTransform(Body body, String phaseName, Map options)
{
boolean isUnsplit = PhaseOptions.getBoolean(options, "unsplit-original-locals");
if(Options.v().verbose())
G.v().out.println("[" + body.getMethod().getName() + "] Packing locals...");
Map<Local, Object> localToGroup = new DeterministicHashMap(body.getLocalCount() * 2 + 1, 0.7f);
// A group represents a bunch of locals which may potentially intefere with each other
// 2 separate groups can not possibly interfere with each other
// (coloring say ints and doubles)
Map<Object, Integer> groupToColorCount = new HashMap<Object, Integer>(body.getLocalCount() * 2 + 1, 0.7f);
Map<Local, Integer> localToColor = new HashMap<Local, Integer>(body.getLocalCount() * 2 + 1, 0.7f);
Map localToNewLocal;
// Assign each local to a group, and set that group's color count to 0.
{
Iterator localIt = body.getLocals().iterator();
while(localIt.hasNext())
{
Local l = (Local) localIt.next();
Object g = l.getType();
localToGroup.put(l, g);
if(!groupToColorCount.containsKey(g))
{
groupToColorCount.put(g, new Integer(0));
}
}
}
// Assign colors to the parameter locals.
{
Iterator codeIt = body.getUnits().iterator();
while(codeIt.hasNext())
{
Unit s = (Unit) codeIt.next();
if(s instanceof IdentityUnit &&
((IdentityUnit) s).getLeftOp() instanceof Local)
{
Local l = (Local) ((IdentityUnit) s).getLeftOp();
Object group = localToGroup.get(l);
int count = groupToColorCount.get(group).intValue();
localToColor.put(l, new Integer(count));
count++;
groupToColorCount.put(group, new Integer(count));
}
}
}
// Call the graph colorer.
if(isUnsplit)
FastColorer.unsplitAssignColorsToLocals(body, localToGroup,
localToColor, groupToColorCount);
else
FastColorer.assignColorsToLocals(body, localToGroup,
localToColor, groupToColorCount);
// Map each local to a new local.
{
List originalLocals = new ArrayList();
localToNewLocal = new HashMap(body.getLocalCount() * 2 + 1, 0.7f);
Map groupIntToLocal = new HashMap(body.getLocalCount() * 2 + 1, 0.7f);
originalLocals.addAll(body.getLocals());
body.getLocals().clear();
Iterator localIt = originalLocals.iterator();
while(localIt.hasNext())
{
Local original = (Local) localIt.next();
Object group = localToGroup.get(original);
int color = localToColor.get(original).intValue();
GroupIntPair pair = new GroupIntPair(group, color);
Local newLocal;
if(groupIntToLocal.containsKey(pair))
newLocal = (Local) groupIntToLocal.get(pair);
else {
newLocal = (Local) original.clone();
newLocal.setType((Type) group);
// Icky fix. But I guess it works. -PL
// It is no substitute for really understanding the
// problem, though. I'll leave that to someone
// who really understands the local naming stuff.
// Does such a person exist?
int signIndex = newLocal.getName().indexOf("#");
if(signIndex != -1)
newLocal.setName(newLocal.getName().substring(0, signIndex));
groupIntToLocal.put(pair, newLocal);
body.getLocals().add(newLocal);
}
localToNewLocal.put(original, newLocal);
}
}
// Go through all valueBoxes of this method and perform changes
{
Iterator codeIt = body.getUnits().iterator();
while(codeIt.hasNext())
{
Unit s = (Unit) codeIt.next();
Iterator boxIt;
boxIt = s.getUseBoxes().iterator();
while(boxIt.hasNext())
{
ValueBox box = (ValueBox) boxIt.next();
if(box.getValue() instanceof Local)
{
Local l = (Local) box.getValue();
box.setValue((Local) localToNewLocal.get(l));
}
}
boxIt = s.getDefBoxes().iterator();
while(boxIt.hasNext())
{
ValueBox box = (ValueBox) boxIt.next();
if(box.getValue() instanceof Local)
{
Local l = (Local) box.getValue();
box.setValue((Local) localToNewLocal.get(l));
}
}
}
}
}
}