/* 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.*;
/**
* A CFG where the nodes are {@link Block} instances, and where
* exception boundaries are taken into account when finding the
* <tt>Block</tt>s for the provided Body. Any {@link Unit} which is
* the first <tt>Unit</tt> to be convered by some exception handler
* will start a new Block, and any <ttUnit</tt> which is the last
* <tt>Unit</tt> to be covered a some exception handler, will end the
* block it is part of. These ``zones'', however, are not split up
* to indicate the possibility that an exception will lead to control
* exiting the zone before it is completed.
*
*/
public class ZonedBlockGraph extends BlockGraph
{
/**
* <p>Constructs a <tt>ZonedBlockGraph</tt> for the <tt>Unit</tt>s
* comprising the passed {@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 a {@link ZonedBlockGraph}
* can use the constructor taking the <tt>BriefUnitGraph</tt> as a
* parameter, as a minor optimization.</p>
*
* @param body The <tt>Body</tt> for which to produce
* a <tt>ZonedBlockGraph</tt>.
*/
public ZonedBlockGraph(Body body)
{
this(new BriefUnitGraph(body));
}
/**
* Constructs a <tt>ZonedBlockGraph</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 produce
* a <tt>ZonedBlockGraph</tt>.
*/
public ZonedBlockGraph(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>The first <tt>Unit</tt> covered by each {@link Trap} (i.e.,
* the <tt>Unit</tt> returned by {@link Trap.getBeginUnit()}.</li>
*
* <li>The first <tt>Unit</tt> not covered by each {@link Trap} (i.e.,
* the <tt>Unit</tt> returned by {@link Trap.getEndUnit()}.</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("ZonedBlockGraph.computeLeaders() called with a UnitGraph that doesn't match its mBody.");
}
Set<Unit> leaders = super.computeLeaders(unitGraph);
for (Iterator it = body.getTraps().iterator(); it.hasNext(); ) {
Trap trap = (Trap) it.next();
leaders.add(trap.getBeginUnit());
leaders.add(trap.getEndUnit());
}
return leaders;
}
}