Robust/src/Analysis/Locality/LocalityAnalysis.java

   1 package Analysis.Locality;
   2
   3 import java.util.*;
   4 import Analysis.CallGraph.CallGraph;
   5 import IR.SymbolTable;
   6 import IR.State;
   7 import IR.TypeUtil;
   8 import IR.MethodDescriptor;
   9 import IR.Flat.*;
  10 import IR.ClassDescriptor;
  11
  12 public class LocalityAnalysis {
  13     State state;
  14     Stack lbtovisit;
  15     Hashtable<LocalityBinding,LocalityBinding> discovered;
  16     Hashtable<LocalityBinding, Set<LocalityBinding>> dependence;
  17     Hashtable<LocalityBinding, Hashtable<FlatNode,Hashtable<TempDescriptor, Integer>>> temptab;
  18     Hashtable<LocalityBinding, Hashtable<FlatNode, Integer>> atomictab;
  19     Hashtable<LocalityBinding, Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>>> tempstosave;
  20     Hashtable<ClassDescriptor, Set<LocalityBinding>> classtolb;
  21
  22     CallGraph callgraph;
  23     TypeUtil typeutil;
  24     public static final Integer LOCAL=new Integer(0);
  25     public static final Integer GLOBAL=new Integer(1);
  26     public static final Integer EITHER=new Integer(2);
  27     public static final Integer CONFLICT=new Integer(3);
  28
  29     public LocalityAnalysis(State state, CallGraph callgraph, TypeUtil typeutil) {
  30         this.typeutil=typeutil;
  31         this.state=state;
  32         this.discovered=new Hashtable<LocalityBinding,LocalityBinding>();
  33         this.dependence=new Hashtable<LocalityBinding, Set<LocalityBinding>>();
  34         this.temptab=new Hashtable<LocalityBinding, Hashtable<FlatNode,Hashtable<TempDescriptor, Integer>>>();
  35         this.atomictab=new Hashtable<LocalityBinding, Hashtable<FlatNode, Integer>>();
  36         this.lbtovisit=new Stack();
  37         this.callgraph=callgraph;
  38         this.tempstosave=new Hashtable<LocalityBinding, Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>>>();
  39         this.classtolb=new Hashtable<ClassDescriptor, Set<LocalityBinding>>();
  40         doAnalysis();
  41     }
  42
  43     /** This method returns a set of LocalityBindings for the parameter class. */
  44
  45     public Set<LocalityBinding> getClassBindings(ClassDescriptor cd) {
  46         return classtolb.get(cd);
  47     }
  48
  49     /** This method returns a set of LocalityBindings.  A
  50      * LocalityBinding specifies a context a method can be invoked in.
  51      * It specifies whether the method is in a transaction and whether
  52      * its parameter objects are locals or globals.  */
  53
  54     public Set<LocalityBinding> getLocalityBindings() {
  55         return discovered.keySet();
  56     }
  57
  58     /** This method returns a hashtable for a given LocalityBinding
  59      * that tells the current local/global status of temps at the each
  60      * node in the flat representation. */
  61
  62     public Hashtable<FlatNode, Hashtable<TempDescriptor, Integer>> getNodeTempInfo(LocalityBinding lb) {
  63         return temptab.get(lb);
  64     }
  65
  66     /** This method returns an hashtable for a given LocalitBinding
  67      * that tells whether a node in the flat represenation is in a
  68      * transaction or not.  Integer values greater than 0 indicate
  69      * that the node is in a transaction and give the nesting depth.
  70      * The outermost AtomicEnterNode will have a value of 1 and the
  71      * outermost AtomicExitNode will have a value of 0. */
  72
  73     public Hashtable<FlatNode, Integer> getAtomic(LocalityBinding lb) {
  74         return atomictab.get(lb);
  75     }
  76
  77     /** This methods returns a hashtable for a given LocalityBinding
  78      * that tells which temps needs to be saved for each
  79      * AtomicEnterNode.  */
  80
  81     public Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>> getTemps(LocalityBinding lb) {
  82         return tempstosave.get(lb);
  83     }
  84
  85     public Set<TempDescriptor> getTempSet(LocalityBinding lb) {
  86         HashSet<TempDescriptor> set=new HashSet<TempDescriptor>();
  87         Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>> table=getTemps(lb);
  88         for(Iterator<FlatAtomicEnterNode> faenit=table.keySet().iterator();faenit.hasNext();) {
  89             FlatAtomicEnterNode faen=faenit.next();
  90             set.addAll(table.get(faen));
  91         }
  92         return set;
  93     }
  94
  95     private void doAnalysis() {
  96         computeLocalityBindings();
  97         computeTempstoSave();
  98     }
  99
 100     private void computeLocalityBindings() {
 101         LocalityBinding lbmain=new LocalityBinding(typeutil.getMain(), false);
 102         lbmain.setGlobal(0, LOCAL);
 103         lbtovisit.add(lbmain);
 104         discovered.put(lbmain, lbmain);
 105         if (!classtolb.containsKey(lbmain.getMethod().getClassDesc()))
 106             classtolb.put(lbmain.getMethod().getClassDesc(), new HashSet<LocalityBinding>());
 107         classtolb.get(lbmain.getMethod().getClassDesc()).add(lbmain);
 108
 109         while(!lbtovisit.empty()) {
 110             LocalityBinding lb=(LocalityBinding) lbtovisit.pop();
 111             Integer returnglobal=lb.getGlobalReturn();
 112             MethodDescriptor md=lb.getMethod();
 113             Hashtable<FlatNode,Hashtable<TempDescriptor, Integer>> temptable=new Hashtable<FlatNode,Hashtable<TempDescriptor, Integer>>();
 114             Hashtable<FlatNode, Integer> atomictable=new Hashtable<FlatNode, Integer>();
 115             computeCallsFlags(md, lb, temptable, atomictable);
 116             atomictab.put(lb, atomictable);
 117             temptab.put(lb, temptable);
 118
 119             if (!md.isStatic()&&!returnglobal.equals(lb.getGlobalReturn())) {
 120                 //return type is more precise now
 121                 //rerun everything that call us
 122                 lbtovisit.addAll(dependence.get(lb));
 123             }
 124         }
 125     }
 126
 127
 128     public void computeCallsFlags(MethodDescriptor md, LocalityBinding lb, Hashtable<FlatNode, Hashtable<TempDescriptor, Integer>> temptable, Hashtable<FlatNode, Integer> atomictable) {
 129         FlatMethod fm=state.getMethodFlat(md);
 130         HashSet<FlatNode> tovisit=new HashSet<FlatNode>();
 131         tovisit.add(fm.getNext(0));
 132         {
 133             // Build table for initial node
 134             Hashtable<TempDescriptor,Integer> table=new Hashtable<TempDescriptor,Integer>();
 135             temptable.put(fm, table);
 136             atomictable.put(fm, lb.isAtomic()?1:0);
 137             int offset=md.isStatic()?0:1;
 138             if (!md.isStatic()) {
 139                 table.put(fm.getParameter(0), lb.getGlobalThis());
 140             }
 141             for(int i=offset;i<fm.numParameters();i++) {
 142                 TempDescriptor temp=fm.getParameter(i);
 143                 Integer b=lb.isGlobal(i-offset);
 144                 table.put(temp,b);
 145             }
 146         }
 147
 148         while(!tovisit.isEmpty()) {
 149             FlatNode fn=tovisit.iterator().next();
 150             tovisit.remove(fn);
 151             Hashtable<TempDescriptor, Integer> currtable=new Hashtable<TempDescriptor, Integer>();
 152             int atomicstate=0;
 153             for(int i=0;i<fn.numPrev();i++) {
 154                 FlatNode prevnode=fn.getPrev(i);
 155                 if (atomictable.containsKey(prevnode)) {
 156                     atomicstate=atomictable.get(prevnode).intValue();
 157                 }
 158                 if (!temptable.containsKey(prevnode))
 159                     continue;
 160                 Hashtable<TempDescriptor, Integer> prevtable=temptable.get(prevnode);
 161                 for(Iterator<TempDescriptor> tempit=prevtable.keySet().iterator();tempit.hasNext();) {
 162                     TempDescriptor temp=tempit.next();
 163                     Integer tmpint=prevtable.get(temp);
 164                     Integer oldint=currtable.containsKey(temp)?currtable.get(temp):EITHER;
 165                     Integer newint=merge(tmpint, oldint);
 166                     currtable.put(temp, newint);
 167                 }
 168             }
 169             atomictable.put(fn, atomicstate);
 170             // Process this node
 171             switch(fn.kind()) {
 172             case FKind.FlatAtomicEnterNode:
 173                 processAtomicEnterNode((FlatAtomicEnterNode)fn, atomictable);
 174                 if (!lb.isAtomic())
 175                     lb.setHasAtomic();
 176                 break;
 177             case FKind.FlatAtomicExitNode:
 178                 processAtomicExitNode((FlatAtomicExitNode)fn, atomictable);
 179                 break;
 180             case FKind.FlatCall:
 181                 processCallNode(lb, (FlatCall)fn, currtable, isAtomic(atomictable, fn));
 182                 break;
 183             case FKind.FlatFieldNode:
 184                 processFieldNode(lb, (FlatFieldNode)fn, isAtomic(atomictable, fn), currtable);
 185                 break;
 186             case FKind.FlatSetFieldNode:
 187                 processSetFieldNode(lb, (FlatSetFieldNode)fn, isAtomic(atomictable,fn), currtable);
 188                 break;
 189             case FKind.FlatNew:
 190                 processNew(lb, (FlatNew)fn, isAtomic(atomictable, fn), currtable);
 191                 break;
 192             case FKind.FlatOpNode:
 193                 processOpNode((FlatOpNode)fn, currtable);
 194                 break;
 195             case FKind.FlatCastNode:
 196                 processCastNode((FlatCastNode)fn, currtable);
 197                 break;
 198             case FKind.FlatLiteralNode:
 199                 processLiteralNode((FlatLiteralNode)fn, currtable);
 200                 break;
 201             case FKind.FlatReturnNode:
 202                 processReturnNode(lb, (FlatReturnNode)fn, currtable);
 203                 break;
 204             case FKind.FlatSetElementNode:
 205                 processSetElementNode(lb, (FlatSetElementNode)fn, currtable, isAtomic(atomictable, fn));
 206                 break;
 207             case FKind.FlatElementNode:
 208                 processElementNode(lb, (FlatElementNode)fn, currtable, isAtomic(atomictable, fn));
 209                 break;
 210             case FKind.FlatCondBranch:
 211             case FKind.FlatBackEdge:
 212             case FKind.FlatNop:
 213                 //No action needed for these
 214                 break;
 215             case FKind.FlatFlagActionNode:
 216             case FKind.FlatCheckNode:
 217             case FKind.FlatTagDeclaration:
 218                 throw new Error("Incompatible with tasks!");
 219             case FKind.FlatMethod:
 220             default:
 221                 throw new Error();
 222             }
 223             Hashtable<TempDescriptor,Integer> oldtable=temptable.get(fn);
 224             if (oldtable==null||!oldtable.equals(currtable)) {
 225                 // Update table for this node
 226                 temptable.put(fn, currtable);
 227                 for(int i=0;i<fn.numNext();i++) {
 228                     tovisit.add(fn.getNext(i));
 229                 }
 230             }
 231         }
 232     }
 233
 234     private static boolean isAtomic(Hashtable<FlatNode, Integer> atomictable, FlatNode fn) {
 235         return atomictable.get(fn).intValue()>0;
 236     }
 237
 238     private static Integer merge(Integer a, Integer b) {
 239         if (a==null||a.equals(EITHER))
 240             return b;
 241         if (b==null||b.equals(EITHER))
 242             return a;
 243         if (a.equals(b))
 244             return a;
 245         return CONFLICT;
 246     }
 247
 248     void processCallNode(LocalityBinding currlb, FlatCall fc, Hashtable<TempDescriptor, Integer> currtable, boolean isatomic) {
 249         MethodDescriptor nodemd=fc.getMethod();
 250         Set methodset=fc.getThis()==null?callgraph.getMethods(nodemd):
 251             callgraph.getMethods(nodemd, fc.getThis().getType());
 252         Integer currreturnval=EITHER; //Start off with the either value
 253         for(Iterator methodit=methodset.iterator();methodit.hasNext();) {
 254             MethodDescriptor md=(MethodDescriptor) methodit.next();
 255             boolean isnative=md.getModifiers().isNative();
 256
 257             LocalityBinding lb=new LocalityBinding(md, isatomic);
 258             if (isnative&&isatomic) {
 259                 System.out.println("Don't call native methods in atomic blocks!");
 260             }
 261             for(int i=0;i<fc.numArgs();i++) {
 262                 TempDescriptor arg=fc.getArg(i);
 263                 if(isnative&&(currtable.get(arg).equals(GLOBAL)||
 264                               currtable.get(arg).equals(CONFLICT)))
 265                    throw new Error("Potential call to native method "+md+" with global parameter:\n"+currlb.getExplanation());
 266                 lb.setGlobal(i,currtable.get(arg));
 267             }
 268             if (fc.getThis()!=null) {
 269                 Integer thistype=currtable.get(fc.getThis());
 270                 if (thistype==null)
 271                     thistype=EITHER;
 272                 if(thistype.equals(CONFLICT))
 273                     throw new Error("Using type that can be either local or global in context:\n"+currlb.getExplanation());
 274                 if(thistype.equals(GLOBAL)&&!isatomic)
 275                     throw new Error("Using global object outside of transaction in context:\n"+currlb.getExplanation());
 276                 if (isnative&&thistype.equals(GLOBAL))
 277                     throw new Error("Potential call to native method "+md+" on global objects:\n"+currlb.getExplanation());
 278                 lb.setGlobalThis(thistype);
 279             } else
 280                 lb.setGlobalThis(EITHER);//default value
 281
 282             //lb is built
 283             if (!discovered.containsKey(lb)) {
 284                 if (isnative)
 285                     lb.setGlobalReturn(LOCAL);
 286                 else
 287                     lb.setGlobalReturn(EITHER);
 288                 lb.setParent(currlb);
 289                 lbtovisit.add(lb);
 290                 discovered.put(lb, lb);
 291                 if (!classtolb.containsKey(lb.getMethod().getClassDesc()))
 292                     classtolb.put(lb.getMethod().getClassDesc(), new HashSet<LocalityBinding>());
 293                 classtolb.get(lb.getMethod().getClassDesc()).add(lb);
 294             } else
 295                 lb=discovered.get(lb);
 296             Integer returnval=lb.getGlobalReturn();
 297             currreturnval=merge(returnval, currreturnval);
 298             if (!dependence.containsKey(lb))
 299                 dependence.put(lb, new HashSet<LocalityBinding>());
 300             dependence.get(lb).add(currlb);
 301         }
 302         if (fc.getReturnTemp()!=null) {
 303             currtable.put(fc.getReturnTemp(), currreturnval);
 304         }
 305     }
 306
 307     void processFieldNode(LocalityBinding lb, FlatFieldNode ffn, boolean transaction, Hashtable<TempDescriptor, Integer> currtable) {
 308         Integer type=currtable.get(ffn.getSrc());
 309         TempDescriptor dst=ffn.getDst();
 310         if (type.equals(LOCAL)) {
 311             if (ffn.getField().isGlobal())
 312                 currtable.put(dst,GLOBAL);
 313             else
 314                 currtable.put(dst,LOCAL);
 315         } else if (type.equals(GLOBAL)) {
 316             if (!transaction)
 317                 throw new Error("Global access outside of a transaction in context:\n"+lb.getExplanation());
 318             if (ffn.getField().getType().isPrimitive())
 319                 currtable.put(dst, LOCAL); // primitives are local
 320             else
 321                 currtable.put(dst, GLOBAL);
 322         } else if (type.equals(EITHER)) {
 323             if (ffn.getField().getType().isPrimitive())
 324                 currtable.put(dst, LOCAL); // primitives are local
 325             else if (ffn.getField().isGlobal())
 326                 currtable.put(dst, GLOBAL);
 327             else
 328                 currtable.put(dst, EITHER);
 329         } else if (type.equals(CONFLICT)) {
 330             throw new Error("Access to object that could be either global or local in context:\n"+lb.getExplanation());
 331         }
 332     }
 333
 334     //need to handle primitives
 335     void processSetFieldNode(LocalityBinding lb, FlatSetFieldNode fsfn, boolean transaction, Hashtable<TempDescriptor, Integer> currtable) {
 336         Integer srctype=currtable.get(fsfn.getSrc());
 337         Integer dsttype=currtable.get(fsfn.getDst());
 338
 339         if (dsttype.equals(LOCAL)) {
 340             if (fsfn.getField().isGlobal()) {
 341                 if (!(srctype.equals(GLOBAL)||srctype.equals(EITHER)))
 342                     throw new Error("Writing possible local reference to global field in context: \n"+lb.getExplanation());
 343             } else {
 344                 if (!(srctype.equals(LOCAL)||srctype.equals(EITHER)))
 345                     throw new Error("Writing possible global reference to local object in context: \n"+lb.getExplanation());
 346             }
 347         } else if (dsttype.equals(GLOBAL)) {
 348             if (!transaction)
 349                 throw new Error("Global access outside of a transaction in context:\n"+lb.getExplanation());
 350             //okay to store primitives in global object
 351             if (srctype.equals(LOCAL) && fsfn.getField().getType().isPrimitive())
 352                 return;
 353             if (!(srctype.equals(GLOBAL)||srctype.equals(EITHER)))
 354                 throw new Error("Writing possible local reference to global object in context:\n"+lb.getExplanation());
 355         } else if (dsttype.equals(EITHER)) {
 356             if (srctype.equals(CONFLICT))
 357                 throw new Error("Using reference that could be local or global in context:\n"+lb.getExplanation());
 358         } else if (dsttype.equals(CONFLICT)) {
 359             throw new Error("Access to object that could be either global or local in context:\n"+lb.getExplanation());
 360         }
 361     }
 362
 363     void processNew(LocalityBinding lb, FlatNew fn, boolean transaction, Hashtable<TempDescriptor, Integer> currtable) {
 364         if (fn.isGlobal()&&!transaction) {
 365             throw new Error("Allocating global object outside of transaction in context:"+lb.getExplanation());
 366         }
 367         if (fn.isGlobal())
 368             currtable.put(fn.getDst(), GLOBAL);
 369         else
 370             currtable.put(fn.getDst(), LOCAL);
 371     }
 372
 373     void processOpNode(FlatOpNode fon, Hashtable<TempDescriptor, Integer> currtable) {
 374         /* Just propagate value */
 375         currtable.put(fon.getDest(), currtable.get(fon.getLeft()));
 376     }
 377
 378     void processCastNode(FlatCastNode fcn, Hashtable<TempDescriptor, Integer> currtable) {
 379         currtable.put(fcn.getDst(), currtable.get(fcn.getSrc()));
 380     }
 381
 382     void processLiteralNode(FlatLiteralNode fln, Hashtable<TempDescriptor, Integer> currtable) {
 383         //null is either
 384         if (fln.getValue()==null)
 385             currtable.put(fln.getDst(), EITHER);
 386         else
 387             currtable.put(fln.getDst(), LOCAL);
 388     }
 389
 390     void processReturnNode(LocalityBinding lb, FlatReturnNode frn, Hashtable<TempDescriptor, Integer> currtable) {
 391         if(frn.getReturnTemp()!=null) {
 392             Integer returntype=currtable.get(frn.getReturnTemp());
 393             lb.setGlobalReturn(merge(returntype, lb.getGlobalReturn()));
 394         }
 395     }
 396
 397     void processSetElementNode(LocalityBinding lb, FlatSetElementNode fsen, Hashtable<TempDescriptor, Integer> currtable, boolean isatomic) {
 398         Integer srctype=currtable.get(fsen.getSrc());
 399         Integer dsttype=currtable.get(fsen.getDst());
 400
 401         if (dsttype.equals(LOCAL)) {
 402             if (!(srctype.equals(LOCAL)||srctype.equals(EITHER)))
 403                 throw new Error("Writing possible global reference to local object in context:\n"+lb.getExplanation());
 404         } else if (dsttype.equals(GLOBAL)) {
 405             if (!(srctype.equals(GLOBAL)||srctype.equals(EITHER)))
 406                 throw new Error("Writing possible local reference to global object in context:\n"+lb.getExplanation());
 407             if (!isatomic)
 408                 throw new Error("Global access outside of a transaction in context:\n"+lb.getExplanation());
 409         } else if (dsttype.equals(EITHER)) {
 410             if (srctype.equals(CONFLICT))
 411                 throw new Error("Using reference that could be local or global in context:\n"+lb.getExplanation());
 412         } else if (dsttype.equals(CONFLICT)) {
 413             throw new Error("Access to object that could be either global or local in context:\n"+lb.getExplanation());
 414         }
 415     }
 416
 417     void processElementNode(LocalityBinding lb, FlatElementNode fen, Hashtable<TempDescriptor, Integer> currtable, boolean isatomic) {
 418         Integer type=currtable.get(fen.getSrc());
 419         TempDescriptor dst=fen.getDst();
 420         if (type.equals(LOCAL)) {
 421             currtable.put(dst,LOCAL);
 422         } else if (type.equals(GLOBAL)) {
 423             if (!isatomic)
 424                 throw new Error("Global access outside of a transaction in context:\n"+lb.getExplanation());
 425             currtable.put(dst, GLOBAL);
 426         } else if (type.equals(EITHER)) {
 427             currtable.put(dst, EITHER);
 428         } else if (type.equals(CONFLICT)) {
 429             throw new Error("Access to object that could be either global or local in context:\n"+lb.getExplanation());
 430         }
 431     }
 432
 433     void processAtomicEnterNode(FlatAtomicEnterNode fen, Hashtable<FlatNode, Integer> atomictable) {
 434         int atomic=atomictable.get(fen).intValue();
 435         atomictable.put(fen, new Integer(atomic+1));
 436     }
 437
 438     void processAtomicExitNode(FlatAtomicExitNode fen, Hashtable<FlatNode, Integer> atomictable) {
 439         int atomic=atomictable.get(fen).intValue();
 440         atomictable.put(fen, new Integer(atomic-1));
 441     }
 442
 443     private Hashtable<FlatNode, Set<TempDescriptor>> computeLiveTemps(FlatMethod fm) {
 444         Hashtable<FlatNode, Set<TempDescriptor>> nodetotemps=new Hashtable<FlatNode, Set<TempDescriptor>>();
 445
 446         Set<FlatNode> toprocess=fm.getNodeSet();
 447
 448         while(!toprocess.isEmpty()) {
 449             FlatNode fn=toprocess.iterator().next();
 450             toprocess.remove(fn);
 451
 452             List<TempDescriptor> reads=Arrays.asList(fn.readsTemps());
 453             List<TempDescriptor> writes=Arrays.asList(fn.readsTemps());
 454
 455             HashSet<TempDescriptor> tempset=new HashSet<TempDescriptor>();
 456             for(int i=0;i<fn.numNext();i++) {
 457                 FlatNode fnnext=fn.getNext(i);
 458                 if (nodetotemps.containsKey(fnnext))
 459                     tempset.addAll(nodetotemps.get(fnnext));
 460             }
 461             tempset.removeAll(writes);
 462             tempset.addAll(reads);
 463             if (!nodetotemps.containsKey(fn)||
 464                 nodetotemps.get(fn).equals(tempset)) {
 465                 nodetotemps.put(fn, tempset);
 466                 for(int i=0;i<fn.numPrev();i++)
 467                     toprocess.add(fn.getPrev(i));
 468             }
 469         }
 470         return nodetotemps;
 471     }
 472
 473     private void computeTempstoSave() {
 474         for(Iterator<LocalityBinding> lbit=getLocalityBindings().iterator();lbit.hasNext();) {
 475             LocalityBinding lb=lbit.next();
 476             computeTempstoSave(lb);
 477         }
 478     }
 479
 480     /* Need to checkpoint all temps that could be read from along any
 481      * path that are either:
 482        1) Written to by any assignment inside the transaction
 483        2) Read from a global temp.
 484
 485        Generate tempstosave map from
 486        localitybinding->flatatomicenternode->Set<TempDescriptors>
 487     */
 488
 489     private void computeTempstoSave(LocalityBinding lb) {
 490         if (lb.isAtomic())
 491             return;
 492         Hashtable<FlatNode, Integer> atomictab=getAtomic(lb);
 493         Hashtable<FlatNode, Hashtable<TempDescriptor, Integer>> temptab=getNodeTempInfo(lb);
 494         MethodDescriptor md=lb.getMethod();
 495         FlatMethod fm=state.getMethodFlat(md);
 496
 497         Hashtable<FlatNode, Set<TempDescriptor>> nodetotemps=computeLiveTemps(fm);
 498         Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>> nodetosavetemps=new Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>>();
 499         tempstosave.put(lb, nodetosavetemps);
 500
 501         Hashtable<FlatNode, FlatAtomicEnterNode> nodemap=new Hashtable<FlatNode, FlatAtomicEnterNode>();
 502
 503         HashSet<FlatNode> toprocess=new HashSet<FlatNode>();
 504         HashSet<FlatNode> discovered=new HashSet<FlatNode>();
 505         toprocess.add(fm);
 506         discovered.add(fm);
 507         while(!toprocess.isEmpty()) {
 508             FlatNode fn=toprocess.iterator().next();
 509             toprocess.remove(fn);
 510             boolean isatomic=atomictab.get(fn).intValue()>0;
 511             if (isatomic&&
 512                 atomictab.get(fn.getPrev(0)).intValue()==0) {
 513                 assert(fn.getPrev(0).kind()==FKind.FlatAtomicEnterNode);
 514                 nodemap.put(fn, (FlatAtomicEnterNode)fn);
 515                 nodetosavetemps.put((FlatAtomicEnterNode)fn, new HashSet<TempDescriptor>());
 516             } else if (isatomic) {
 517                 FlatAtomicEnterNode atomicnode=nodemap.get(fn);
 518                 Set<TempDescriptor> livetemps=nodetotemps.get(fn);
 519                 List<TempDescriptor> reads=Arrays.asList(fn.readsTemps());
 520                 List<TempDescriptor> writes=Arrays.asList(fn.readsTemps());
 521
 522                 for(Iterator<TempDescriptor> tempit=livetemps.iterator();tempit.hasNext();) {
 523                     TempDescriptor tmp=tempit.next();
 524                     if (writes.contains(tmp)) {
 525                         nodetosavetemps.get(fn).add(tmp);
 526                     } else if (reads.contains(tmp)&&temptab.get(fn).get(tmp)==GLOBAL) {
 527                         nodetosavetemps.get(fn).add(tmp);
 528                     }
 529                 }
 530             }
 531             for(int i=0;i<fn.numNext();i++) {
 532                 FlatNode fnnext=fn.getNext(i);
 533                 if (!discovered.contains(fnnext)) {
 534                     discovered.add(fnnext);
 535                     toprocess.add(fnnext);
 536                     if(isatomic) {
 537                         nodemap.put(fnnext, nodemap.get(fn));
 538                     }
 539                 }
 540             }
 541         }
 542     }
 543 }