/* Soot - a J*va Optimization Framework
 * Copyright (C) 2003 Jennifer Lhotak
 *
 * 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 soot.jimple.toolkits.callgraph;

import soot.*;
import java.util.*;
import soot.jimple.*;
import soot.toolkits.graph.*;
import soot.toolkits.scalar.*;

public class ClinitElimAnalysis extends ForwardFlowAnalysis {
	
	private UnitGraph g;

	public ClinitElimAnalysis(UnitGraph g) {
		super(g);
		this.g = g;

		doAnalysis();
	}

	public void merge(Object in1, Object in2, Object out) {
		
		FlowSet inSet1 = (FlowSet) in1;
		FlowSet inSet2 = (FlowSet) in2;
		FlowSet outSet = (FlowSet) out;

		inSet1.intersection(inSet2, outSet);
	}

	public void copy(Object src, Object dest) {
		
		FlowSet srcIn = (FlowSet) src;
		FlowSet destOut = (FlowSet) dest;

		srcIn.copy(destOut);
	}

	
	// out(s) = in(s) intersect { target methods of s where edge kind is clinit}
	protected void flowThrough(Object inVal, Object stmt, Object outVal) {
		FlowSet in = (FlowSet) inVal;
		FlowSet out = (FlowSet) outVal;
		Stmt s = (Stmt) stmt;
		
        in.copy(out);

		CallGraph cg = Scene.v().getCallGraph();

		Iterator edges = cg.edgesOutOf(s);

		while (edges.hasNext()){
			Edge e = (Edge)edges.next();
			if (e.isClinit()) {
				out.add(e.tgt());
			}
		}
	}

	protected Object entryInitialFlow(){
		
		return new ArraySparseSet();
		
		
	}

	protected Object newInitialFlow(){
		ArraySparseSet set = new ArraySparseSet();
		CallGraph cg = Scene.v().getCallGraph();

		Iterator mIt = cg.edgesOutOf(g.getBody().getMethod());
		while (mIt.hasNext()){
			Edge edge = (Edge)mIt.next();
			if (edge.isClinit()){
				set.add(edge.tgt());
			}
		}

		return set;
	}
}