/* Soot - a J*va Optimization Framework
* Copyright (C) 1999 Patrice Pominville, 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 1997-2003.
* 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.graph;
import java.util.*;
import soot.*;
import soot.jimple.Stmt;
/**
* A CFG where the nodes are {@link Block} instances, and where
* {@link Unit}s which include array references start new blocks.
* Exceptional control flow is ignored, so
* the graph will be a forest where each exception handler
* constitutes a disjoint subgraph.
*/
public class ArrayRefBlockGraph extends BlockGraph
{
/**
* <p>Constructs an {@link ArrayRefBlockGraph} from the given
* {@link Body}.</p>
*
* <p> Note that this constructor builds a {@link
* BriefUnitGraph} internally when splitting <tt>body</tt>'s
* {@link Unit}s into {@link Block}s. Callers who need both a
* {@link BriefUnitGraph} and an {@link ArrayRefBlockGraph}
* should use the constructor taking the <tt>BriefUnitGraph</tt> as a
* parameter, as a minor optimization.</p>
*
* @param the Body instance from which the graph is built.
*/
public ArrayRefBlockGraph(Body body)
{
this(new BriefUnitGraph(body));
}
/**
* Constructs an <tt>ArrayRefBlockGraph</tt> corresponding to the
* <tt>Unit</tt>-level control flow represented by the
* passed {@link BriefUnitGraph}.
*
* @param unitGraph The <tt>BriefUnitGraph</tt> for which
* to build an <tt>ArrayRefBlockGraph</tt>.
*/
public ArrayRefBlockGraph(BriefUnitGraph unitGraph)
{
super(unitGraph);
}
/**
* <p>Utility method for computing the basic block leaders for a
* {@link Body}, given its {@link UnitGraph} (i.e., the
* instructions which begin new basic blocks).</p>
*
* <p> This implementation chooses as block leaders all
* the <tt>Unit</tt>s that {@link BlockGraph.computerLeaders()},
* and adds:
*
* <ul>
*
* <li>All <tt>Unit</tt>s which contain an array reference, as
* defined by {@link Stmt.containsArrayRef()} and
* {@link Inst.containsArrayRef()}.
*
* <li>The first <tt>Unit</tt> not covered by each {@link Trap} (i.e.,
* the <tt>Unit</tt> returned by {@link Trap.getLastUnit()}.</li>
*
* </ul></p>
*
* @param unitGraph is the <tt>Unit</tt>-level CFG which is to be split
* into basic blocks.
*
* @return the {@link Set} of {@link Unit}s in <tt>unitGraph</tt> which
* are block leaders.
*/
protected Set<Unit> computeLeaders(UnitGraph unitGraph) {
Body body = unitGraph.getBody();
if (body != mBody) {
throw new RuntimeException("ArrayRefBlockGraph.computeLeaders() called with a UnitGraph that doesn't match its mBody.");
}
Set<Unit> leaders = super.computeLeaders(unitGraph);
for (Iterator it = body.getUnits().iterator(); it.hasNext(); ) {
Unit unit = (Unit) it.next();
if (((unit instanceof Stmt) && ((Stmt) unit).containsArrayRef())) {
leaders.add(unit);
}
}
return leaders;
}
}