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     Hashtable<MethodDescriptor, Set<LocalityBinding>> methodtolb;
  22     private LocalityBinding lbmain;
  23
  24     CallGraph callgraph;
  25     TypeUtil typeutil;
  26     public static final Integer LOCAL=new Integer(0);
  27     public static final Integer GLOBAL=new Integer(1);
  28     public static final Integer EITHER=new Integer(2);
  29     public static final Integer CONFLICT=new Integer(3);
  30
  31     public LocalityAnalysis(State state, CallGraph callgraph, TypeUtil typeutil) {
  32         this.typeutil=typeutil;
  33         this.state=state;
  34         this.discovered=new Hashtable<LocalityBinding,LocalityBinding>();
  35         this.dependence=new Hashtable<LocalityBinding, Set<LocalityBinding>>();
  36         this.temptab=new Hashtable<LocalityBinding, Hashtable<FlatNode,Hashtable<TempDescriptor, Integer>>>();
  37         this.atomictab=new Hashtable<LocalityBinding, Hashtable<FlatNode, Integer>>();
  38         this.lbtovisit=new Stack();
  39         this.callgraph=callgraph;
  40         this.tempstosave=new Hashtable<LocalityBinding, Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>>>();
  41         this.classtolb=new Hashtable<ClassDescriptor, Set<LocalityBinding>>();
  42         this.methodtolb=new Hashtable<MethodDescriptor, Set<LocalityBinding>>();
  43         doAnalysis();
  44     }
  45
  46     public LocalityBinding getMain() {
  47         return lbmain;
  48     }
  49
  50     /** This method returns the set of LocalityBindings that a given
  51      * flatcall could invoke */
  52
  53     public LocalityBinding getBinding(LocalityBinding currlb, FlatCall fc) {
  54         boolean isatomic=getAtomic(currlb).get(fc).intValue()>0;
  55         Hashtable<TempDescriptor, Integer> currtable=getNodeTempInfo(currlb).get(fc);
  56         MethodDescriptor md=fc.getMethod();
  57
  58         boolean isnative=md.getModifiers().isNative();
  59
  60         LocalityBinding lb=new LocalityBinding(md, isatomic);
  61
  62         for(int i=0;i<fc.numArgs();i++) {
  63             TempDescriptor arg=fc.getArg(i);
  64             lb.setGlobal(i,currtable.get(arg));
  65         }
  66         if (fc.getThis()!=null) {
  67             Integer thistype=currtable.get(fc.getThis());
  68             if (thistype==null)
  69                 thistype=EITHER;
  70             lb.setGlobalThis(thistype);
  71         } else
  72             lb.setGlobalThis(EITHER);//default value
  73         if (discovered.containsKey(lb))
  74             lb=discovered.get(lb);
  75         else throw new Error();
  76         return lb;
  77     }
  78
  79
  80     /** This method returns a set of LocalityBindings for the parameter class. */
  81
  82     public Set<LocalityBinding> getClassBindings(ClassDescriptor cd) {
  83         return classtolb.get(cd);
  84     }
  85
  86     /** This method returns a set of LocalityBindings for the parameter method. */
  87
  88     public Set<LocalityBinding> getMethodBindings(MethodDescriptor md) {
  89         return methodtolb.get(md);
  90     }
  91
  92     /** This method returns a set of LocalityBindings.  A
  93      * LocalityBinding specifies a context a method can be invoked in.
  94      * It specifies whether the method is in a transaction and whether
  95      * its parameter objects are locals or globals.  */
  96
  97     public Set<LocalityBinding> getLocalityBindings() {
  98         return discovered.keySet();
  99     }
 100
 101     /** This method returns a hashtable for a given LocalityBinding
 102      * that tells the current local/global status of temps at the each
 103      * node in the flat representation. */
 104
 105     public Hashtable<FlatNode, Hashtable<TempDescriptor, Integer>> getNodeTempInfo(LocalityBinding lb) {
 106         return temptab.get(lb);
 107     }
 108
 109     /** This method returns an hashtable for a given LocalitBinding
 110      * that tells whether a node in the flat represenation is in a
 111      * transaction or not.  Integer values greater than 0 indicate
 112      * that the node is in a transaction and give the nesting depth.
 113      * The outermost AtomicEnterNode will have a value of 1 and the
 114      * outermost AtomicExitNode will have a value of 0. */
 115
 116     public Hashtable<FlatNode, Integer> getAtomic(LocalityBinding lb) {
 117         return atomictab.get(lb);
 118     }
 119
 120     /** This methods returns a hashtable for a given LocalityBinding
 121      * that tells which temps needs to be saved for each
 122      * AtomicEnterNode.  */
 123
 124     public Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>> getTemps(LocalityBinding lb) {
 125         return tempstosave.get(lb);
 126     }
 127
 128     public Set<TempDescriptor> getTempSet(LocalityBinding lb) {
 129         HashSet<TempDescriptor> set=new HashSet<TempDescriptor>();
 130         Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>> table=getTemps(lb);
 131         for(Iterator<FlatAtomicEnterNode> faenit=table.keySet().iterator();faenit.hasNext();) {
 132             FlatAtomicEnterNode faen=faenit.next();
 133             set.addAll(table.get(faen));
 134         }
 135         return set;
 136     }
 137
 138     private void doAnalysis() {
 139         computeLocalityBindings();
 140         computeTempstoSave();
 141     }
 142
 143     private void computeLocalityBindings() {
 144         lbmain=new LocalityBinding(typeutil.getMain(), false);
 145         lbmain.setGlobal(0, LOCAL);
 146         lbtovisit.add(lbmain);
 147         discovered.put(lbmain, lbmain);
 148         if (!classtolb.containsKey(lbmain.getMethod().getClassDesc()))
 149             classtolb.put(lbmain.getMethod().getClassDesc(), new HashSet<LocalityBinding>());
 150         classtolb.get(lbmain.getMethod().getClassDesc()).add(lbmain);
 151
 152         if (!methodtolb.containsKey(lbmain.getMethod()))
 153             methodtolb.put(lbmain.getMethod(), new HashSet<LocalityBinding>());
 154         methodtolb.get(lbmain.getMethod()).add(lbmain);
 155
 156         while(!lbtovisit.empty()) {
 157             LocalityBinding lb=(LocalityBinding) lbtovisit.pop();
 158             Integer returnglobal=lb.getGlobalReturn();
 159             MethodDescriptor md=lb.getMethod();
 160             Hashtable<FlatNode,Hashtable<TempDescriptor, Integer>> temptable=new Hashtable<FlatNode,Hashtable<TempDescriptor, Integer>>();
 161             Hashtable<FlatNode, Integer> atomictable=new Hashtable<FlatNode, Integer>();
 162             computeCallsFlags(md, lb, temptable, atomictable);
 163             atomictab.put(lb, atomictable);
 164             temptab.put(lb, temptable);
 165
 166             if (!md.isStatic()&&!returnglobal.equals(lb.getGlobalReturn())) {
 167                 //return type is more precise now
 168                 //rerun everything that call us
 169                 lbtovisit.addAll(dependence.get(lb));
 170             }
 171         }
 172     }
 173
 174
 175     public void computeCallsFlags(MethodDescriptor md, LocalityBinding lb, Hashtable<FlatNode, Hashtable<TempDescriptor, Integer>> temptable, Hashtable<FlatNode, Integer> atomictable) {
 176         FlatMethod fm=state.getMethodFlat(md);
 177         HashSet<FlatNode> tovisit=new HashSet<FlatNode>();
 178         tovisit.add(fm.getNext(0));
 179         {
 180             // Build table for initial node
 181             Hashtable<TempDescriptor,Integer> table=new Hashtable<TempDescriptor,Integer>();
 182             temptable.put(fm, table);
 183             atomictable.put(fm, lb.isAtomic()?1:0);
 184             int offset=md.isStatic()?0:1;
 185             if (!md.isStatic()) {
 186                 table.put(fm.getParameter(0), lb.getGlobalThis());
 187             }
 188             for(int i=offset;i<fm.numParameters();i++) {
 189                 TempDescriptor temp=fm.getParameter(i);
 190                 Integer b=lb.isGlobal(i-offset);
 191                 table.put(temp,b);
 192             }
 193         }
 194
 195         while(!tovisit.isEmpty()) {
 196             FlatNode fn=tovisit.iterator().next();
 197             tovisit.remove(fn);
 198             Hashtable<TempDescriptor, Integer> currtable=new Hashtable<TempDescriptor, Integer>();
 199             int atomicstate=0;
 200             for(int i=0;i<fn.numPrev();i++) {
 201                 FlatNode prevnode=fn.getPrev(i);
 202                 if (atomictable.containsKey(prevnode)) {
 203                     atomicstate=atomictable.get(prevnode).intValue();
 204                 }
 205                 if (!temptable.containsKey(prevnode))
 206                     continue;
 207                 Hashtable<TempDescriptor, Integer> prevtable=temptable.get(prevnode);
 208                 for(Iterator<TempDescriptor> tempit=prevtable.keySet().iterator();tempit.hasNext();) {
 209                     TempDescriptor temp=tempit.next();
 210                     Integer tmpint=prevtable.get(temp);
 211                     Integer oldint=currtable.containsKey(temp)?currtable.get(temp):EITHER;
 212                     Integer newint=merge(tmpint, oldint);
 213                     currtable.put(temp, newint);
 214                 }
 215             }
 216             atomictable.put(fn, atomicstate);
 217             // Process this node
 218             switch(fn.kind()) {
 219             case FKind.FlatAtomicEnterNode:
 220                 processAtomicEnterNode((FlatAtomicEnterNode)fn, atomictable);
 221                 if (!lb.isAtomic())
 222                     lb.setHasAtomic();
 223                 break;
 224             case FKind.FlatAtomicExitNode:
 225                 processAtomicExitNode((FlatAtomicExitNode)fn, atomictable);
 226                 break;
 227             case FKind.FlatCall:
 228                 processCallNode(lb, (FlatCall)fn, currtable, isAtomic(atomictable, fn));
 229                 break;
 230             case FKind.FlatFieldNode:
 231                 processFieldNode(lb, (FlatFieldNode)fn, isAtomic(atomictable, fn), currtable);
 232                 break;
 233             case FKind.FlatSetFieldNode:
 234                 processSetFieldNode(lb, (FlatSetFieldNode)fn, isAtomic(atomictable,fn), currtable);
 235                 break;
 236             case FKind.FlatNew:
 237                 processNew(lb, (FlatNew)fn, isAtomic(atomictable, fn), currtable);
 238                 break;
 239             case FKind.FlatOpNode:
 240                 processOpNode((FlatOpNode)fn, currtable);
 241                 break;
 242             case FKind.FlatCastNode:
 243                 processCastNode((FlatCastNode)fn, currtable);
 244                 break;
 245             case FKind.FlatLiteralNode:
 246                 processLiteralNode((FlatLiteralNode)fn, currtable);
 247                 break;
 248             case FKind.FlatReturnNode:
 249                 processReturnNode(lb, (FlatReturnNode)fn, currtable);
 250                 break;
 251             case FKind.FlatSetElementNode:
 252                 processSetElementNode(lb, (FlatSetElementNode)fn, currtable, isAtomic(atomictable, fn));
 253                 break;
 254             case FKind.FlatElementNode:
 255                 processElementNode(lb, (FlatElementNode)fn, currtable, isAtomic(atomictable, fn));
 256                 break;
 257             case FKind.FlatCondBranch:
 258             case FKind.FlatBackEdge:
 259             case FKind.FlatNop:
 260                 //No action needed for these
 261                 break;
 262             case FKind.FlatFlagActionNode:
 263             case FKind.FlatCheckNode:
 264             case FKind.FlatTagDeclaration:
 265                 throw new Error("Incompatible with tasks!");
 266             case FKind.FlatMethod:
 267             default:
 268                 throw new Error();
 269             }
 270             Hashtable<TempDescriptor,Integer> oldtable=temptable.get(fn);
 271             if (oldtable==null||!oldtable.equals(currtable)) {
 272                 // Update table for this node
 273                 temptable.put(fn, currtable);
 274                 for(int i=0;i<fn.numNext();i++) {
 275                     tovisit.add(fn.getNext(i));
 276                 }
 277             }
 278         }
 279     }
 280
 281     private static boolean isAtomic(Hashtable<FlatNode, Integer> atomictable, FlatNode fn) {
 282         return atomictable.get(fn).intValue()>0;
 283     }
 284
 285     private static Integer merge(Integer a, Integer b) {
 286         if (a==null||a.equals(EITHER))
 287             return b;
 288         if (b==null||b.equals(EITHER))
 289             return a;
 290         if (a.equals(b))
 291             return a;
 292         return CONFLICT;
 293     }
 294
 295     void processCallNode(LocalityBinding currlb, FlatCall fc, Hashtable<TempDescriptor, Integer> currtable, boolean isatomic) {
 296         MethodDescriptor nodemd=fc.getMethod();
 297         Set methodset=null;
 298         if (nodemd.isStatic()||nodemd.getReturnType()==null) {
 299             methodset=new HashSet();
 300             methodset.add(nodemd);
 301         } else {
 302             methodset=callgraph.getMethods(nodemd, fc.getThis().getType());
 303         }
 304         Integer currreturnval=EITHER; //Start off with the either value
 305         for(Iterator methodit=methodset.iterator();methodit.hasNext();) {
 306             MethodDescriptor md=(MethodDescriptor) methodit.next();
 307             boolean isnative=md.getModifiers().isNative();
 308
 309             LocalityBinding lb=new LocalityBinding(md, isatomic);
 310             if (isnative&&isatomic) {
 311                 System.out.println("Don't call native methods in atomic blocks!");
 312             }
 313             for(int i=0;i<fc.numArgs();i++) {
 314                 TempDescriptor arg=fc.getArg(i);
 315                 if(isnative&&(currtable.get(arg).equals(GLOBAL)||
 316                               currtable.get(arg).equals(CONFLICT)))
 317                    throw new Error("Potential call to native method "+md+" with global parameter:\n"+currlb.getExplanation());
 318                 lb.setGlobal(i,currtable.get(arg));
 319             }
 320             if (fc.getThis()!=null) {
 321                 Integer thistype=currtable.get(fc.getThis());
 322                 if (thistype==null)
 323                     thistype=EITHER;
 324                 if(thistype.equals(CONFLICT))
 325                     throw new Error("Using type that can be either local or global in context:\n"+currlb.getExplanation());
 326                 if(thistype.equals(GLOBAL)&&!isatomic)
 327                     throw new Error("Using global object outside of transaction in context:\n"+currlb.getExplanation());
 328                 if (isnative&&thistype.equals(GLOBAL))
 329                     throw new Error("Potential call to native method "+md+" on global objects:\n"+currlb.getExplanation());
 330                 lb.setGlobalThis(thistype);
 331             } else
 332                 lb.setGlobalThis(EITHER);//default value
 333
 334             //lb is built
 335             if (!discovered.containsKey(lb)) {
 336                 if (isnative)
 337                     lb.setGlobalReturn(LOCAL);
 338                 else
 339                     lb.setGlobalReturn(EITHER);
 340                 lb.setParent(currlb);
 341                 lbtovisit.add(lb);
 342                 discovered.put(lb, lb);
 343                 if (!classtolb.containsKey(lb.getMethod().getClassDesc()))
 344                     classtolb.put(lb.getMethod().getClassDesc(), new HashSet<LocalityBinding>());
 345                 classtolb.get(lb.getMethod().getClassDesc()).add(lb);
 346                 if (!methodtolb.containsKey(lb.getMethod()))
 347                     methodtolb.put(lb.getMethod(), new HashSet<LocalityBinding>());
 348                 methodtolb.get(lb.getMethod()).add(lb);
 349             } else
 350                 lb=discovered.get(lb);
 351             Integer returnval=lb.getGlobalReturn();
 352             currreturnval=merge(returnval, currreturnval);
 353             if (!dependence.containsKey(lb))
 354                 dependence.put(lb, new HashSet<LocalityBinding>());
 355             dependence.get(lb).add(currlb);
 356         }
 357         if (fc.getReturnTemp()!=null) {
 358             currtable.put(fc.getReturnTemp(), currreturnval);
 359         }
 360     }
 361
 362     void processFieldNode(LocalityBinding lb, FlatFieldNode ffn, boolean transaction, Hashtable<TempDescriptor, Integer> currtable) {
 363         Integer type=currtable.get(ffn.getSrc());
 364         TempDescriptor dst=ffn.getDst();
 365         if (type.equals(LOCAL)) {
 366             if (ffn.getField().isGlobal())
 367                 currtable.put(dst,GLOBAL);
 368             else
 369                 currtable.put(dst,LOCAL);
 370         } else if (type.equals(GLOBAL)) {
 371             if (!transaction)
 372                 throw new Error("Global access outside of a transaction in context:\n"+lb.getExplanation());
 373             if (ffn.getField().getType().isPrimitive())
 374                 currtable.put(dst, LOCAL); // primitives are local
 375             else
 376                 currtable.put(dst, GLOBAL);
 377         } else if (type.equals(EITHER)) {
 378             if (ffn.getField().getType().isPrimitive())
 379                 currtable.put(dst, LOCAL); // primitives are local
 380             else if (ffn.getField().isGlobal())
 381                 currtable.put(dst, GLOBAL);
 382             else
 383                 currtable.put(dst, EITHER);
 384         } else if (type.equals(CONFLICT)) {
 385             throw new Error("Access to object that could be either global or local in context:\n"+lb.getExplanation());
 386         }
 387     }
 388
 389     //need to handle primitives
 390     void processSetFieldNode(LocalityBinding lb, FlatSetFieldNode fsfn, boolean transaction, Hashtable<TempDescriptor, Integer> currtable) {
 391         Integer srctype=currtable.get(fsfn.getSrc());
 392         Integer dsttype=currtable.get(fsfn.getDst());
 393
 394         if (dsttype.equals(LOCAL)) {
 395             if (fsfn.getField().isGlobal()) {
 396                 if (!(srctype.equals(GLOBAL)||srctype.equals(EITHER)))
 397                     throw new Error("Writing possible local reference to global field in context: \n"+lb.getExplanation());
 398             } else {
 399                 if (!(srctype.equals(LOCAL)||srctype.equals(EITHER)))
 400                     throw new Error("Writing possible global reference to local object in context: \n"+lb.getExplanation());
 401             }
 402         } else if (dsttype.equals(GLOBAL)) {
 403             if (!transaction)
 404                 throw new Error("Global access outside of a transaction in context:\n"+lb.getExplanation());
 405             //okay to store primitives in global object
 406             if (srctype.equals(LOCAL) && fsfn.getField().getType().isPrimitive())
 407                 return;
 408             if (!(srctype.equals(GLOBAL)||srctype.equals(EITHER)))
 409                 throw new Error("Writing possible local reference to global object in context:\n"+lb.getExplanation());
 410         } else if (dsttype.equals(EITHER)) {
 411             if (srctype.equals(CONFLICT))
 412                 throw new Error("Using reference that could be local or global in context:\n"+lb.getExplanation());
 413         } else if (dsttype.equals(CONFLICT)) {
 414             throw new Error("Access to object that could be either global or local in context:\n"+lb.getExplanation());
 415         }
 416     }
 417
 418     void processNew(LocalityBinding lb, FlatNew fn, boolean transaction, Hashtable<TempDescriptor, Integer> currtable) {
 419         if (fn.isGlobal()&&!transaction) {
 420             throw new Error("Allocating global object outside of transaction in context:"+lb.getExplanation());
 421         }
 422         if (fn.isGlobal())
 423             currtable.put(fn.getDst(), GLOBAL);
 424         else
 425             currtable.put(fn.getDst(), LOCAL);
 426     }
 427
 428     void processOpNode(FlatOpNode fon, Hashtable<TempDescriptor, Integer> currtable) {
 429         /* Just propagate value */
 430         currtable.put(fon.getDest(), currtable.get(fon.getLeft()));
 431     }
 432
 433     void processCastNode(FlatCastNode fcn, Hashtable<TempDescriptor, Integer> currtable) {
 434         currtable.put(fcn.getDst(), currtable.get(fcn.getSrc()));
 435     }
 436
 437     void processLiteralNode(FlatLiteralNode fln, Hashtable<TempDescriptor, Integer> currtable) {
 438         //null is either
 439         if (fln.getValue()==null)
 440             currtable.put(fln.getDst(), EITHER);
 441         else
 442             currtable.put(fln.getDst(), LOCAL);
 443     }
 444
 445     void processReturnNode(LocalityBinding lb, FlatReturnNode frn, Hashtable<TempDescriptor, Integer> currtable) {
 446         if(frn.getReturnTemp()!=null) {
 447             Integer returntype=currtable.get(frn.getReturnTemp());
 448             lb.setGlobalReturn(merge(returntype, lb.getGlobalReturn()));
 449         }
 450     }
 451
 452     void processSetElementNode(LocalityBinding lb, FlatSetElementNode fsen, Hashtable<TempDescriptor, Integer> currtable, boolean isatomic) {
 453         Integer srctype=currtable.get(fsen.getSrc());
 454         Integer dsttype=currtable.get(fsen.getDst());
 455
 456         if (dsttype.equals(LOCAL)) {
 457             if (!(srctype.equals(LOCAL)||srctype.equals(EITHER)))
 458                 throw new Error("Writing possible global reference to local object in context:\n"+lb.getExplanation());
 459         } else if (dsttype.equals(GLOBAL)) {
 460             if (!(srctype.equals(GLOBAL)||srctype.equals(EITHER)))
 461                 throw new Error("Writing possible local reference to global object in context:\n"+lb.getExplanation());
 462             if (!isatomic)
 463                 throw new Error("Global access outside of a transaction in context:\n"+lb.getExplanation());
 464         } else if (dsttype.equals(EITHER)) {
 465             if (srctype.equals(CONFLICT))
 466                 throw new Error("Using reference that could be local or global in context:\n"+lb.getExplanation());
 467         } else if (dsttype.equals(CONFLICT)) {
 468             throw new Error("Access to object that could be either global or local in context:\n"+lb.getExplanation());
 469         }
 470     }
 471
 472     void processElementNode(LocalityBinding lb, FlatElementNode fen, Hashtable<TempDescriptor, Integer> currtable, boolean isatomic) {
 473         Integer type=currtable.get(fen.getSrc());
 474         TempDescriptor dst=fen.getDst();
 475         if (type.equals(LOCAL)) {
 476             currtable.put(dst,LOCAL);
 477         } else if (type.equals(GLOBAL)) {
 478             if (!isatomic)
 479                 throw new Error("Global access outside of a transaction in context:\n"+lb.getExplanation());
 480             currtable.put(dst, GLOBAL);
 481         } else if (type.equals(EITHER)) {
 482             currtable.put(dst, EITHER);
 483         } else if (type.equals(CONFLICT)) {
 484             throw new Error("Access to object that could be either global or local in context:\n"+lb.getExplanation());
 485         }
 486     }
 487
 488     void processAtomicEnterNode(FlatAtomicEnterNode fen, Hashtable<FlatNode, Integer> atomictable) {
 489         int atomic=atomictable.get(fen).intValue();
 490         atomictable.put(fen, new Integer(atomic+1));
 491     }
 492
 493     void processAtomicExitNode(FlatAtomicExitNode fen, Hashtable<FlatNode, Integer> atomictable) {
 494         int atomic=atomictable.get(fen).intValue();
 495         atomictable.put(fen, new Integer(atomic-1));
 496     }
 497
 498     private Hashtable<FlatNode, Set<TempDescriptor>> computeLiveTemps(FlatMethod fm) {
 499         Hashtable<FlatNode, Set<TempDescriptor>> nodetotemps=new Hashtable<FlatNode, Set<TempDescriptor>>();
 500
 501         Set<FlatNode> toprocess=fm.getNodeSet();
 502
 503         while(!toprocess.isEmpty()) {
 504             FlatNode fn=toprocess.iterator().next();
 505             toprocess.remove(fn);
 506
 507             List<TempDescriptor> reads=Arrays.asList(fn.readsTemps());
 508             List<TempDescriptor> writes=Arrays.asList(fn.readsTemps());
 509
 510             HashSet<TempDescriptor> tempset=new HashSet<TempDescriptor>();
 511             for(int i=0;i<fn.numNext();i++) {
 512                 FlatNode fnnext=fn.getNext(i);
 513                 if (nodetotemps.containsKey(fnnext))
 514                     tempset.addAll(nodetotemps.get(fnnext));
 515             }
 516             tempset.removeAll(writes);
 517             tempset.addAll(reads);
 518             if (!nodetotemps.containsKey(fn)||
 519                 nodetotemps.get(fn).equals(tempset)) {
 520                 nodetotemps.put(fn, tempset);
 521                 for(int i=0;i<fn.numPrev();i++)
 522                     toprocess.add(fn.getPrev(i));
 523             }
 524         }
 525         return nodetotemps;
 526     }
 527
 528     private void computeTempstoSave() {
 529         for(Iterator<LocalityBinding> lbit=getLocalityBindings().iterator();lbit.hasNext();) {
 530             LocalityBinding lb=lbit.next();
 531             computeTempstoSave(lb);
 532         }
 533     }
 534
 535     /* Need to checkpoint all temps that could be read from along any
 536      * path that are either:
 537        1) Written to by any assignment inside the transaction
 538        2) Read from a global temp.
 539
 540        Generate tempstosave map from
 541        localitybinding->flatatomicenternode->Set<TempDescriptors>
 542     */
 543
 544     private void computeTempstoSave(LocalityBinding lb) {
 545         if (lb.isAtomic())
 546             return;
 547         Hashtable<FlatNode, Integer> atomictab=getAtomic(lb);
 548         Hashtable<FlatNode, Hashtable<TempDescriptor, Integer>> temptab=getNodeTempInfo(lb);
 549         MethodDescriptor md=lb.getMethod();
 550         FlatMethod fm=state.getMethodFlat(md);
 551
 552         Hashtable<FlatNode, Set<TempDescriptor>> nodetotemps=computeLiveTemps(fm);
 553         Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>> nodetosavetemps=new Hashtable<FlatAtomicEnterNode, Set<TempDescriptor>>();
 554         tempstosave.put(lb, nodetosavetemps);
 555
 556         Hashtable<FlatNode, FlatAtomicEnterNode> nodemap=new Hashtable<FlatNode, FlatAtomicEnterNode>();
 557
 558         HashSet<FlatNode> toprocess=new HashSet<FlatNode>();
 559         HashSet<FlatNode> discovered=new HashSet<FlatNode>();
 560         toprocess.add(fm);
 561         discovered.add(fm);
 562         while(!toprocess.isEmpty()) {
 563             FlatNode fn=toprocess.iterator().next();
 564             toprocess.remove(fn);
 565             boolean isatomic=atomictab.get(fn).intValue()>0;
 566             if (isatomic&&
 567                 atomictab.get(fn.getPrev(0)).intValue()==0) {
 568                 assert(fn.getPrev(0).kind()==FKind.FlatAtomicEnterNode);
 569                 nodemap.put(fn, (FlatAtomicEnterNode)fn);
 570                 nodetosavetemps.put((FlatAtomicEnterNode)fn, new HashSet<TempDescriptor>());
 571             } else if (isatomic) {
 572                 FlatAtomicEnterNode atomicnode=nodemap.get(fn);
 573                 Set<TempDescriptor> livetemps=nodetotemps.get(fn);
 574                 List<TempDescriptor> reads=Arrays.asList(fn.readsTemps());
 575                 List<TempDescriptor> writes=Arrays.asList(fn.readsTemps());
 576
 577                 for(Iterator<TempDescriptor> tempit=livetemps.iterator();tempit.hasNext();) {
 578                     TempDescriptor tmp=tempit.next();
 579                     if (writes.contains(tmp)) {
 580                         nodetosavetemps.get(fn).add(tmp);
 581                     } else if (reads.contains(tmp)&&temptab.get(fn).get(tmp)==GLOBAL) {
 582                         nodetosavetemps.get(fn).add(tmp);
 583                     }
 584                 }
 585             }
 586             for(int i=0;i<fn.numNext();i++) {
 587                 FlatNode fnnext=fn.getNext(i);
 588                 if (!discovered.contains(fnnext)) {
 589                     discovered.add(fnnext);
 590                     toprocess.add(fnnext);
 591                     if(isatomic) {
 592                         nodemap.put(fnnext, nodemap.get(fn));
 593                     }
 594                 }
 595             }
 596         }
 597     }
 598 }