1 cananian 1.1.2.6 // ForwardDataFlowBasicBlockVisitor.java, created Wed Mar 10 9:00:53 1999 by jwhaley
2 cananian 1.1.2.9 // Copyright (C) 1998 John Whaley <jwhaley@alum.mit.edu>
3 cananian 1.1.2.5 // Licensed under the terms of the GNU GPL; see COPYING for details.
4 jwhaley 1.1.2.1 package harpoon.Analysis.DataFlow;
5 jwhaley 1.1.2.1
6 salcianu 1.4 import harpoon.Analysis.BasicBlockInterf;
7 salcianu 1.4 import java.util.Iterator;
8 cananian 1.5 import net.cscott.jutil.WorkSet;
9 pnkfelix 1.1.2.3
10 jwhaley 1.1.2.1 /**
11 jwhaley 1.1.2.1 * ForwardDataFlowBasicBlockVisitor
12 jwhaley 1.1.2.1 *
13 cananian 1.1.2.9 * @author John Whaley <jwhaley@alum.mit.edu>
14 cananian 1.6 * @version $Id: ForwardDataFlowBasicBlockVisitor.java,v 1.6 2004/02/08 03:19:21 cananian Exp $
15 jwhaley 1.1.2.1 */
16 jwhaley 1.1.2.1
17 jwhaley 1.1.2.1 public abstract class ForwardDataFlowBasicBlockVisitor extends DataFlowBasicBlockVisitor {
18 pnkfelix 1.1.2.4
19 pnkfelix 1.1.2.4 private static final boolean DEBUG = false;
20 jwhaley 1.1.2.1
21 pnkfelix 1.1.2.8 /** Performs the <i>merge</i> operation between <code>q</code> and
22 pnkfelix 1.1.2.8 its successors, readding <code>BasicBlock</code>s to
23 pnkfelix 1.1.2.8 <code>W</code> where necessary.
24 pnkfelix 1.1.2.8 <BR> <B>effects:</B> Runs <code>merge(q, s)</code> for all
25 pnkfelix 1.1.2.8 <code>s</code> element of Successors(<code>q</code>).
26 pnkfelix 1.1.2.8 If the <code>merge(q, s)</code> operation returns
27 pnkfelix 1.1.2.8 <code>true</code> for a given <code>s</code>, adds
28 pnkfelix 1.1.2.8 <code>s</code> to <code>W</code>, indicating that
29 pnkfelix 1.1.2.8 <code>s</code> must be revisited by <code>this</code>.
30 cananian 1.3 @see #merge(BasicBlock, BasicBlock)
31 pnkfelix 1.1.2.2 */
32 cananian 1.5 public void addSuccessors(WorkSet W, BasicBlockInterf q) {
33 salcianu 1.4 if (DEBUG) db("adding successors of " + q + " to worklist");
34 pnkfelix 1.1.2.2
35 cananian 1.6 for (Object qnO : q.nextSet()) {
36 cananian 1.6 BasicBlockInterf qn = (BasicBlockInterf) qnO;
37 pnkfelix 1.1.2.2
38 salcianu 1.4 if (DEBUG) db("looking at " + q + " -> " + qn);
39 salcianu 1.4
40 salcianu 1.4 if (merge(q, qn)) {
41 salcianu 1.4
42 salcianu 1.4 if (DEBUG) db("added " + qn + " to the work queue");
43 salcianu 1.4
44 cananian 1.5 W.add(qn); // in set changed -- need to revisit target node
45 salcianu 1.4 }
46 jwhaley 1.1.2.1 }
47 jwhaley 1.1.2.1 }
48 jwhaley 1.1.2.1
49 jwhaley 1.1.2.1 }
50 cananian 1.2