1 package Analysis.Loops;
4 import java.util.Iterator;
5 import java.util.Hashtable;
6 import java.util.HashSet;
9 public class CopyPropagation {
10 public CopyPropagation() {
13 public void optimize(FlatMethod fm) {
14 Hashtable<FlatNode, Hashtable<TempDescriptor, TempDescriptor>> table
15 =new Hashtable<FlatNode, Hashtable<TempDescriptor, TempDescriptor>>();
16 boolean changed=false;
19 HashSet tovisit=new HashSet();
20 HashSet discovered=new HashSet();
23 while(!tovisit.isEmpty()) {
24 FlatNode fn=(FlatNode) tovisit.iterator().next();
26 for(int i=0;i<fn.numNext();i++) {
27 FlatNode nnext=fn.getNext(i);
28 if (!discovered.contains(nnext)) {
29 discovered.add(nnext);
33 Hashtable<TempDescriptor, TempDescriptor> tab;
34 if (fn.numPrev()>=1&&table.containsKey(fn.getPrev(0)))
35 tab=new Hashtable<TempDescriptor, TempDescriptor>(table.get(fn.getPrev(0)));
37 tab=new Hashtable<TempDescriptor, TempDescriptor>();
38 //Compute intersection
39 for(int i=1;i<fn.numPrev();i++) {
40 Hashtable<TempDescriptor, TempDescriptor> tp=table.get(fn.getPrev(i));
41 for(Iterator tmpit=tab.entrySet().iterator();tmpit.hasNext();) {
42 Map.Entry t=(Map.Entry)tmpit.next();
43 TempDescriptor tmp=(TempDescriptor)t.getKey();
44 if (tp!=null&&(!tp.containsKey(tmp)||tp.get(tmp)!=tab.get(tmp))) {
49 TempDescriptor[]writes=fn.writesTemps();
50 for(int i=0;i<writes.length;i++) {
51 TempDescriptor tmp=writes[i];
52 for(Iterator<TempDescriptor> tmpit=tab.keySet().iterator();tmpit.hasNext();) {
53 TempDescriptor tmp2=tmpit.next();
54 if (tmp==tab.get(tmp2))
58 if (fn.kind()==FKind.FlatOpNode) {
59 FlatOpNode fon=(FlatOpNode)fn;
60 if (fon.getOp().getOp()==Operation.ASSIGN) {
61 tab.put(fon.getDest(), fon.getLeft());
64 if (!table.containsKey(fn)||!table.get(fn).equals(tab)) {
67 for(int i=0;i<fn.numNext();i++) {
68 FlatNode nnext=fn.getNext(i);
73 for(Iterator<FlatNode> it=fm.getNodeSet().iterator();it.hasNext();) {
74 FlatNode fn=it.next();
75 Hashtable<TempDescriptor, TempDescriptor> tab=table.get(fn);
77 TempDescriptor[]reads=fn.readsTemps();
78 for(int i=0;i<reads.length;i++) {
79 TempDescriptor tmp=reads[i];
80 if (tab.containsKey(tmp)) {
83 tmap.addPair(tmp, tab.get(tmp));