Robust/src/Analysis/Locality/DiscoverConflicts.java

   1 package Analysis.Locality;
   2
   3 import IR.Flat.*;
   4 import java.util.Set;
   5 import java.util.Arrays;
   6 import java.util.HashSet;
   7 import java.util.Iterator;
   8 import java.util.Hashtable;
   9 import IR.State;
  10 import IR.Operation;
  11 import IR.TypeDescriptor;
  12 import IR.MethodDescriptor;
  13 import IR.FieldDescriptor;
  14
  15 public class DiscoverConflicts {
  16   Set<FieldDescriptor> fields;
  17   Set<TypeDescriptor> arrays;
  18   LocalityAnalysis locality;
  19   State state;
  20   Hashtable<LocalityBinding, Set<FlatNode>> treadmap;
  21   Hashtable<LocalityBinding, Set<TempFlatPair>> transreadmap;
  22   Hashtable<LocalityBinding, Set<FlatNode>> srcmap;
  23   Hashtable<LocalityBinding, Set<FlatNode>> leftsrcmap;
  24   Hashtable<LocalityBinding, Set<FlatNode>> rightsrcmap;
  25   TypeAnalysis typeanalysis;
  26   Hashtable<LocalityBinding, HashSet<FlatNode>>cannotdelaymap;
  27   Hashtable<LocalityBinding, Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>>> lbtofnmap;
  28
  29
  30   public DiscoverConflicts(LocalityAnalysis locality, State state, TypeAnalysis typeanalysis) {
  31     this.locality=locality;
  32     this.fields=new HashSet<FieldDescriptor>();
  33     this.arrays=new HashSet<TypeDescriptor>();
  34     this.state=state;
  35     this.typeanalysis=typeanalysis;
  36     transreadmap=new Hashtable<LocalityBinding, Set<TempFlatPair>>();
  37     treadmap=new Hashtable<LocalityBinding, Set<FlatNode>>();
  38     srcmap=new Hashtable<LocalityBinding, Set<FlatNode>>();
  39     leftsrcmap=new Hashtable<LocalityBinding, Set<FlatNode>>();
  40     rightsrcmap=new Hashtable<LocalityBinding, Set<FlatNode>>();
  41     lbtofnmap=new Hashtable<LocalityBinding, Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>>>();
  42   }
  43
  44   public DiscoverConflicts(LocalityAnalysis locality, State state, TypeAnalysis typeanalysis, Hashtable<LocalityBinding, HashSet<FlatNode>> cannotdelaymap) {
  45     this.locality=locality;
  46     this.fields=new HashSet<FieldDescriptor>();
  47     this.arrays=new HashSet<TypeDescriptor>();
  48     this.state=state;
  49     this.typeanalysis=typeanalysis;
  50     this.cannotdelaymap=cannotdelaymap;
  51     transreadmap=new Hashtable<LocalityBinding, Set<TempFlatPair>>();
  52     treadmap=new Hashtable<LocalityBinding, Set<FlatNode>>();
  53     srcmap=new Hashtable<LocalityBinding, Set<FlatNode>>();
  54     leftsrcmap=new Hashtable<LocalityBinding, Set<FlatNode>>();
  55     rightsrcmap=new Hashtable<LocalityBinding, Set<FlatNode>>();
  56     lbtofnmap=new Hashtable<LocalityBinding, Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>>>();
  57   }
  58
  59   public Set<FieldDescriptor> getFields() {
  60     return fields;
  61   }
  62
  63   public Set<TypeDescriptor> getArrays() {
  64     return arrays;
  65   }
  66
  67   public void doAnalysis() {
  68     //Compute fields and arrays for all transactions.  Note that we
  69     //only look at changes to old objects
  70
  71     Set<LocalityBinding> localityset=locality.getLocalityBindings();
  72     for(Iterator<LocalityBinding> lb=localityset.iterator();lb.hasNext();) {
  73       computeModified(lb.next());
  74     }
  75     expandTypes();
  76     //Compute set of nodes that need transread
  77     for(Iterator<LocalityBinding> lb=localityset.iterator();lb.hasNext();) {
  78       LocalityBinding l=lb.next();
  79       analyzeLocality(l);
  80       setNeedReadTrans(l);
  81     }
  82   }
  83
  84   //Change flatnode/temp pairs to just flatnodes that need transactional reads
  85
  86   public void setNeedReadTrans(LocalityBinding lb) {
  87     HashSet<FlatNode> set=new HashSet<FlatNode>();
  88     for(Iterator<TempFlatPair> it=transreadmap.get(lb).iterator();it.hasNext();) {
  89       TempFlatPair tfp=it.next();
  90       set.add(tfp.f);
  91     }
  92     treadmap.put(lb, set);
  93   }
  94
  95   //We have a set of things we write to, figure out what things this
  96   //could effect.
  97   public void expandTypes() {
  98     Set<TypeDescriptor> expandedarrays=new HashSet<TypeDescriptor>();
  99     for(Iterator<TypeDescriptor> it=arrays.iterator();it.hasNext();) {
 100       TypeDescriptor td=it.next();
 101       expandedarrays.addAll(typeanalysis.expand(td));
 102     }
 103     arrays=expandedarrays;
 104   }
 105
 106   Hashtable<TempDescriptor, Set<TempFlatPair>> doMerge(FlatNode fn, Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>> tmptofnset) {
 107     Hashtable<TempDescriptor, Set<TempFlatPair>> table=new Hashtable<TempDescriptor, Set<TempFlatPair>>();
 108     for(int i=0;i<fn.numPrev();i++) {
 109       FlatNode fprev=fn.getPrev(i);
 110       Hashtable<TempDescriptor, Set<TempFlatPair>> tabset=tmptofnset.get(fprev);
 111       if (tabset!=null) {
 112         for(Iterator<TempDescriptor> tmpit=tabset.keySet().iterator();tmpit.hasNext();) {
 113           TempDescriptor td=tmpit.next();
 114           Set<TempFlatPair> fnset=tabset.get(td);
 115           if (!table.containsKey(td))
 116             table.put(td, new HashSet<TempFlatPair>());
 117           table.get(td).addAll(fnset);
 118         }
 119       }
 120     }
 121     return table;
 122   }
 123
 124   public Set<FlatNode> getNeedSrcTrans(LocalityBinding lb) {
 125     return srcmap.get(lb);
 126   }
 127
 128   public boolean getNeedSrcTrans(LocalityBinding lb, FlatNode fn) {
 129     return srcmap.get(lb).contains(fn);
 130   }
 131
 132   public boolean getNeedLeftSrcTrans(LocalityBinding lb, FlatNode fn) {
 133     return leftsrcmap.get(lb).contains(fn);
 134   }
 135
 136   public boolean getNeedRightSrcTrans(LocalityBinding lb, FlatNode fn) {
 137     return rightsrcmap.get(lb).contains(fn);
 138   }
 139
 140   public boolean getNeedTrans(LocalityBinding lb, FlatNode fn) {
 141     return treadmap.get(lb).contains(fn);
 142   }
 143
 144   public Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>> getMap(LocalityBinding lb) {
 145     return lbtofnmap.get(lb);
 146   }
 147
 148   private void analyzeLocality(LocalityBinding lb) {
 149     MethodDescriptor md=lb.getMethod();
 150     FlatMethod fm=state.getMethodFlat(md);
 151     Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>> fnmap=computeTempSets(lb);
 152     lbtofnmap.put(lb,fnmap);
 153     HashSet<TempFlatPair> tfset=computeTranslationSet(lb, fm, fnmap);
 154     HashSet<FlatNode> srctrans=new HashSet<FlatNode>();
 155     HashSet<FlatNode> leftsrctrans=new HashSet<FlatNode>();
 156     HashSet<FlatNode> rightsrctrans=new HashSet<FlatNode>();
 157     transreadmap.put(lb, tfset);
 158     srcmap.put(lb,srctrans);
 159     leftsrcmap.put(lb,leftsrctrans);
 160     rightsrcmap.put(lb,rightsrctrans);
 161
 162     //compute writes that need translation on source
 163
 164     for(Iterator<FlatNode> fnit=fm.getNodeSet().iterator();fnit.hasNext();) {
 165       FlatNode fn=fnit.next();
 166       Hashtable<FlatNode, Integer> atomictable=locality.getAtomic(lb);
 167       if (atomictable.get(fn).intValue()>0) {
 168         Hashtable<TempDescriptor, Set<TempFlatPair>> tmap=fnmap.get(fn);
 169         switch(fn.kind()) {
 170
 171           //We might need to translate arguments to pointer comparison
 172
 173         case FKind.FlatOpNode: {
 174           FlatOpNode fon=(FlatOpNode)fn;
 175           if (fon.getOp().getOp()==Operation.EQUAL||
 176               fon.getOp().getOp()==Operation.NOTEQUAL) {
 177             if (!fon.getLeft().getType().isPtr())
 178               break;
 179             Set<TempFlatPair> lefttfpset=tmap.get(fon.getLeft());
 180             Set<TempFlatPair> righttfpset=tmap.get(fon.getRight());
 181             //handle left operand
 182             if (lefttfpset!=null) {
 183               for(Iterator<TempFlatPair> tfpit=lefttfpset.iterator();tfpit.hasNext();) {
 184                 TempFlatPair tfp=tfpit.next();
 185                 if (tfset.contains(tfp)||outofscope(tfp)) {
 186                   leftsrctrans.add(fon);
 187                   break;
 188                 }
 189               }
 190             }
 191             //handle right operand
 192             if (righttfpset!=null) {
 193               for(Iterator<TempFlatPair> tfpit=righttfpset.iterator();tfpit.hasNext();) {
 194                 TempFlatPair tfp=tfpit.next();
 195                 if (tfset.contains(tfp)||outofscope(tfp)) {
 196                   rightsrctrans.add(fon);
 197                   break;
 198                 }
 199               }
 200             }
 201           }
 202           break;
 203         }
 204
 205         case FKind.FlatGlobalConvNode: {
 206           //need to translate these if the value we read from may be a
 207           //shadow...  check this by seeing if any of the values we
 208           //may read are in the transread set or came from our caller
 209           //or a method we called
 210
 211           FlatGlobalConvNode fgcn=(FlatGlobalConvNode)fn;
 212           if (fgcn.getLocality()!=lb||
 213               fgcn.getMakePtr())
 214             break;
 215
 216           Set<TempFlatPair> tfpset=tmap.get(fgcn.getSrc());
 217
 218           if (tfpset!=null) {
 219             for(Iterator<TempFlatPair> tfpit=tfpset.iterator();tfpit.hasNext();) {
 220               TempFlatPair tfp=tfpit.next();
 221               if (tfset.contains(tfp)||outofscope(tfp)) {
 222                 srctrans.add(fgcn);
 223                 break;
 224               }
 225             }
 226           }
 227           break;
 228         }
 229
 230         case FKind.FlatSetFieldNode: {
 231           //need to translate these if the value we read from may be a
 232           //shadow...  check this by seeing if any of the values we
 233           //may read are in the transread set or came from our caller
 234           //or a method we called
 235
 236           FlatSetFieldNode fsfn=(FlatSetFieldNode)fn;
 237           if (!fsfn.getField().getType().isPtr())
 238             break;
 239           Set<TempFlatPair> tfpset=tmap.get(fsfn.getSrc());
 240           if (tfpset!=null) {
 241             for(Iterator<TempFlatPair> tfpit=tfpset.iterator();tfpit.hasNext();) {
 242               TempFlatPair tfp=tfpit.next();
 243               if (tfset.contains(tfp)||outofscope(tfp)) {
 244                 srctrans.add(fsfn);
 245                 break;
 246               }
 247             }
 248           }
 249           break;
 250         }
 251         case FKind.FlatSetElementNode: {
 252           //need to translate these if the value we read from may be a
 253           //shadow...  check this by seeing if any of the values we
 254           //may read are in the transread set or came from our caller
 255           //or a method we called
 256
 257           FlatSetElementNode fsen=(FlatSetElementNode)fn;
 258           if (!fsen.getSrc().getType().isPtr())
 259             break;
 260           Set<TempFlatPair> tfpset=tmap.get(fsen.getSrc());
 261           if (tfpset!=null) {
 262             for(Iterator<TempFlatPair> tfpit=tfpset.iterator();tfpit.hasNext();) {
 263               TempFlatPair tfp=tfpit.next();
 264               if (tfset.contains(tfp)||outofscope(tfp)) {
 265                 srctrans.add(fsen);
 266                 break;
 267               }
 268             }
 269           }
 270           break;
 271         }
 272         default:
 273         }
 274       }
 275     }
 276   }
 277
 278   public boolean outofscope(TempFlatPair tfp) {
 279     FlatNode fn=tfp.f;
 280     return fn.kind()==FKind.FlatCall||fn.kind()==FKind.FlatMethod;
 281   }
 282
 283
 284   /** Need to figure out which nodes need a transread to make local
 285   copies.  Transread conceptually tracks conflicts.  This depends on
 286   what fields/elements are accessed We iterate over all flatnodes that
 287   access fields...If these accesses could conflict, we mark the source
 288   tempflat pair as needing a transread */
 289
 290   HashSet<TempFlatPair> computeTranslationSet(LocalityBinding lb, FlatMethod fm, Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>> fnmap) {
 291     HashSet<TempFlatPair> tfset=new HashSet<TempFlatPair>();
 292
 293     for(Iterator<FlatNode> fnit=fm.getNodeSet().iterator();fnit.hasNext();) {
 294       FlatNode fn=fnit.next();
 295       Hashtable<FlatNode, Integer> atomictable=locality.getAtomic(lb);
 296
 297       //Check whether this node matters for delayed computation
 298       if (cannotdelaymap!=null&&cannotdelaymap.containsKey(lb)&&!cannotdelaymap.get(lb).contains(fn))
 299         continue;
 300
 301       if (atomictable.get(fn).intValue()>0) {
 302         Hashtable<TempDescriptor, Set<TempFlatPair>> tmap=fnmap.get(fn);
 303         switch(fn.kind()) {
 304         case FKind.FlatElementNode: {
 305           FlatElementNode fen=(FlatElementNode)fn;
 306           if (arrays.contains(fen.getSrc().getType())) {
 307             //this could cause conflict...figure out conflict set
 308             Set<TempFlatPair> tfpset=tmap.get(fen.getSrc());
 309             if (tfpset!=null)
 310               tfset.addAll(tfpset);
 311           }
 312           break;
 313         }
 314         case FKind.FlatFieldNode: {
 315           FlatFieldNode ffn=(FlatFieldNode)fn;
 316           if (fields.contains(ffn.getField())) {
 317             //this could cause conflict...figure out conflict set
 318             Set<TempFlatPair> tfpset=tmap.get(ffn.getSrc());
 319             if (tfpset!=null)
 320               tfset.addAll(tfpset);
 321           }
 322           break;
 323         }
 324         case FKind.FlatSetFieldNode: {
 325           //definitely need to translate these
 326           FlatSetFieldNode fsfn=(FlatSetFieldNode)fn;
 327           Set<TempFlatPair> tfpset=tmap.get(fsfn.getDst());
 328           if (tfpset!=null)
 329             tfset.addAll(tfpset);
 330           break;
 331         }
 332         case FKind.FlatSetElementNode: {
 333           //definitely need to translate these
 334           FlatSetElementNode fsen=(FlatSetElementNode)fn;
 335           Set<TempFlatPair> tfpset=tmap.get(fsen.getDst());
 336           if (tfpset!=null)
 337             tfset.addAll(tfpset);
 338           break;
 339         }
 340         case FKind.FlatCall: //assume pessimistically that calls do bad things
 341         case FKind.FlatReturnNode: {
 342           TempDescriptor []readarray=fn.readsTemps();
 343           for(int i=0;i<readarray.length;i++) {
 344             TempDescriptor rtmp=readarray[i];
 345             Set<TempFlatPair> tfpset=tmap.get(rtmp);
 346             if (tfpset!=null)
 347               tfset.addAll(tfpset);
 348           }
 349           break;
 350         }
 351         default:
 352           //do nothing
 353         }
 354       }
 355     }
 356     return tfset;
 357   }
 358
 359
 360   //This method generates as output for each node
 361   //A map from from temps to a set of temp/flat pairs that the
 362   //original temp points to
 363   //A temp/flat pair gives the flatnode that the value was created at
 364   //and the original temp
 365
 366   Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>> computeTempSets(LocalityBinding lb) {
 367     Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>> tmptofnset=new Hashtable<FlatNode, Hashtable<TempDescriptor, Set<TempFlatPair>>>();
 368     HashSet<FlatNode> discovered=new HashSet<FlatNode>();
 369     HashSet<FlatNode> tovisit=new HashSet<FlatNode>();
 370     MethodDescriptor md=lb.getMethod();
 371     FlatMethod fm=state.getMethodFlat(md);
 372     Hashtable<FlatNode, Integer> atomictable=locality.getAtomic(lb);
 373     Hashtable<FlatNode, Set<TempDescriptor>> livetemps=locality.computeLiveTemps(fm);
 374     tovisit.add(fm);
 375     discovered.add(fm);
 376
 377     while(!tovisit.isEmpty()) {
 378       FlatNode fn=tovisit.iterator().next();
 379       tovisit.remove(fn);
 380       for(int i=0;i<fn.numNext();i++) {
 381         FlatNode fnext=fn.getNext(i);
 382         if (!discovered.contains(fnext)) {
 383           discovered.add(fnext);
 384           tovisit.add(fnext);
 385         }
 386       }
 387       Hashtable<TempDescriptor, Set<TempFlatPair>> ttofn=null;
 388       if (atomictable.get(fn).intValue()!=0) {
 389         if ((fn.numPrev()>0)&&atomictable.get(fn.getPrev(0)).intValue()==0) {
 390           //atomic node, start with new set
 391           ttofn=new Hashtable<TempDescriptor, Set<TempFlatPair>>();
 392         } else {
 393           ttofn=doMerge(fn, tmptofnset);
 394           switch(fn.kind()) {
 395           case FKind.FlatGlobalConvNode: {
 396             FlatGlobalConvNode fgcn=(FlatGlobalConvNode)fn;
 397             if (lb==fgcn.getLocality()&&
 398                 fgcn.getMakePtr()) {
 399               TempDescriptor[] writes=fn.writesTemps();
 400               for(int i=0;i<writes.length;i++) {
 401                 TempDescriptor wtmp=writes[i];
 402                 HashSet<TempFlatPair> set=new HashSet<TempFlatPair>();
 403                 set.add(new TempFlatPair(wtmp, fn));
 404                 ttofn.put(wtmp, set);
 405               }
 406             }
 407             break;
 408           }
 409           case FKind.FlatFieldNode:
 410           case FKind.FlatElementNode: {
 411             TempDescriptor[] writes=fn.writesTemps();
 412             for(int i=0;i<writes.length;i++) {
 413               TempDescriptor wtmp=writes[i];
 414               HashSet<TempFlatPair> set=new HashSet<TempFlatPair>();
 415               set.add(new TempFlatPair(wtmp, fn));
 416               ttofn.put(wtmp, set);
 417             }
 418             break;
 419           }
 420           case FKind.FlatCall:
 421           case FKind.FlatMethod: {
 422             TempDescriptor[] writes=fn.writesTemps();
 423             for(int i=0;i<writes.length;i++) {
 424               TempDescriptor wtmp=writes[i];
 425               HashSet<TempFlatPair> set=new HashSet<TempFlatPair>();
 426               set.add(new TempFlatPair(wtmp, fn));
 427               ttofn.put(wtmp, set);
 428             }
 429             break;
 430           }
 431           case FKind.FlatOpNode: {
 432             FlatOpNode fon=(FlatOpNode)fn;
 433             if (fon.getOp().getOp()==Operation.ASSIGN&&fon.getDest().getType().isPtr()&&
 434                 ttofn.containsKey(fon.getLeft())) {
 435               ttofn.put(fon.getDest(), new HashSet<TempFlatPair>(ttofn.get(fon.getLeft())));
 436               break;
 437             }
 438           }
 439           default:
 440             //Do kill computation
 441             TempDescriptor[] writes=fn.writesTemps();
 442             for(int i=0;i<writes.length;i++) {
 443               TempDescriptor wtmp=writes[i];
 444               ttofn.remove(writes[i]);
 445             }
 446           }
 447         }
 448         if (ttofn!=null) {
 449           if (!tmptofnset.containsKey(fn)||
 450               !tmptofnset.get(fn).equals(ttofn)) {
 451             //enqueue nodes to process
 452             tmptofnset.put(fn, ttofn);
 453             for(int i=0;i<fn.numNext();i++) {
 454               FlatNode fnext=fn.getNext(i);
 455               tovisit.add(fnext);
 456             }
 457           }
 458         }
 459       }
 460     }
 461     return tmptofnset;
 462   }
 463
 464   /* See what fields and arrays transactions might modify.  We only
 465    * look at changes to old objects. */
 466
 467   public void computeModified(LocalityBinding lb) {
 468     MethodDescriptor md=lb.getMethod();
 469     FlatMethod fm=state.getMethodFlat(md);
 470     Hashtable<FlatNode, Set<TempDescriptor>> oldtemps=computeOldTemps(lb);
 471     for(Iterator<FlatNode> fnit=fm.getNodeSet().iterator();fnit.hasNext();) {
 472       FlatNode fn=fnit.next();
 473       Hashtable<FlatNode, Integer> atomictable=locality.getAtomic(lb);
 474       if (atomictable.get(fn).intValue()>0) {
 475         switch (fn.kind()) {
 476         case FKind.FlatSetFieldNode:
 477           FlatSetFieldNode fsfn=(FlatSetFieldNode) fn;
 478           fields.add(fsfn.getField());
 479           break;
 480         case FKind.FlatSetElementNode:
 481           FlatSetElementNode fsen=(FlatSetElementNode) fn;
 482           arrays.add(fsen.getDst().getType());
 483           break;
 484         default:
 485         }
 486       }
 487     }
 488   }
 489
 490
 491   //Returns a table that maps a flatnode to a set of temporaries
 492   //This set of temporaries is old (meaning they may point to object
 493   //allocated before the beginning of the current transaction
 494
 495   Hashtable<FlatNode, Set<TempDescriptor>> computeOldTemps(LocalityBinding lb) {
 496     Hashtable<FlatNode, Set<TempDescriptor>> fntooldtmp=new Hashtable<FlatNode, Set<TempDescriptor>>();
 497     HashSet<FlatNode> discovered=new HashSet<FlatNode>();
 498     HashSet<FlatNode> tovisit=new HashSet<FlatNode>();
 499     MethodDescriptor md=lb.getMethod();
 500     FlatMethod fm=state.getMethodFlat(md);
 501     Hashtable<FlatNode, Integer> atomictable=locality.getAtomic(lb);
 502     Hashtable<FlatNode, Set<TempDescriptor>> livetemps=locality.computeLiveTemps(fm);
 503     tovisit.add(fm);
 504     discovered.add(fm);
 505
 506     while(!tovisit.isEmpty()) {
 507       FlatNode fn=tovisit.iterator().next();
 508       tovisit.remove(fn);
 509       for(int i=0;i<fn.numNext();i++) {
 510         FlatNode fnext=fn.getNext(i);
 511         if (!discovered.contains(fnext)) {
 512           discovered.add(fnext);
 513           tovisit.add(fnext);
 514         }
 515       }
 516       HashSet<TempDescriptor> oldtemps=null;
 517       if (atomictable.get(fn).intValue()!=0) {
 518         if ((fn.numPrev()>0)&&atomictable.get(fn.getPrev(0)).intValue()==0) {
 519           //Everything live is old
 520           Set<TempDescriptor> lives=livetemps.get(fn);
 521           oldtemps=new HashSet<TempDescriptor>();
 522
 523           for(Iterator<TempDescriptor> it=lives.iterator();it.hasNext();) {
 524             TempDescriptor tmp=it.next();
 525             if (tmp.getType().isPtr()) {
 526               oldtemps.add(tmp);
 527             }
 528           }
 529         } else {
 530           oldtemps=new HashSet<TempDescriptor>();
 531           //Compute union of old temporaries
 532           for(int i=0;i<fn.numPrev();i++) {
 533             Set<TempDescriptor> pset=fntooldtmp.get(fn.getPrev(i));
 534             if (pset!=null)
 535               oldtemps.addAll(pset);
 536           }
 537
 538           switch (fn.kind()) {
 539           case FKind.FlatNew:
 540             oldtemps.removeAll(Arrays.asList(fn.readsTemps()));
 541             break;
 542           case FKind.FlatOpNode: {
 543             FlatOpNode fon=(FlatOpNode)fn;
 544             if (fon.getOp().getOp()==Operation.ASSIGN&&fon.getDest().getType().isPtr()) {
 545               if (oldtemps.contains(fon.getLeft()))
 546                 oldtemps.add(fon.getDest());
 547               else
 548                 oldtemps.remove(fon.getDest());
 549               break;
 550             }
 551           }
 552           default: {
 553             TempDescriptor[] writes=fn.writesTemps();
 554             for(int i=0;i<writes.length;i++) {
 555               TempDescriptor wtemp=writes[i];
 556               if (wtemp.getType().isPtr())
 557                 oldtemps.add(wtemp);
 558             }
 559           }
 560           }
 561         }
 562       }
 563
 564       if (oldtemps!=null) {
 565         if (!fntooldtmp.containsKey(fn)||!fntooldtmp.get(fn).equals(oldtemps)) {
 566           fntooldtmp.put(fn, oldtemps);
 567           //propagate changes
 568           for(int i=0;i<fn.numNext();i++) {
 569             FlatNode fnext=fn.getNext(i);
 570             tovisit.add(fnext);
 571           }
 572         }
 573       }
 574     }
 575     return fntooldtmp;
 576   }
 577 }
 578
 579 class TempFlatPair {
 580     FlatNode f;
 581     TempDescriptor t;
 582     TempFlatPair(TempDescriptor t, FlatNode f) {
 583         this.t=t;
 584         this.f=f;
 585     }
 586
 587     public int hashCode() {
 588         return f.hashCode()^t.hashCode();
 589     }
 590     public boolean equals(Object o) {
 591         TempFlatPair tf=(TempFlatPair)o;
 592         return t.equals(tf.t)&&f.equals(tf.f);
 593     }
 594 }