Repair/RepairCompiler/MCC/IR/UpdateNode.java

   1 package MCC.IR;
   2 import java.util.*;
   3 import MCC.State;
   4
   5 class UpdateNode {
   6     Vector updates;
   7     Vector bindings;
   8     Vector invariants;
   9     Hashtable binding;
  10     Rule rule;
  11
  12     public UpdateNode(Rule r) {
  13         updates=new Vector();
  14         bindings=new Vector();
  15         invariants=new Vector();
  16         binding=new Hashtable();
  17         rule=r;
  18     }
  19
  20     public Rule getRule() {
  21         return rule;
  22     }
  23
  24     public String toString() {
  25         String st="";
  26         st+="Bindings:\n";
  27         for(int i=0;i<bindings.size();i++)
  28             st+=bindings.get(i).toString()+"\n";
  29         st+="---------------------\n";
  30         st+="Updates:\n";
  31         for(int i=0;i<updates.size();i++)
  32             st+=updates.get(i).toString()+"\n";
  33         st+="---------------------\n";
  34         st+="Invariants:\n";
  35         for(int i=0;i<invariants.size();i++)
  36             st+=((Expr)invariants.get(i)).name()+"\n";
  37         st+="---------------------\n";
  38         return st;
  39     }
  40
  41     public void addBindings(Vector v) {
  42         for (int i=0;i<v.size();i++) {
  43             addBinding((Binding)v.get(i));
  44         }
  45     }
  46
  47     public boolean checkupdates() {
  48         if (!checkconflicts()) /* Do we have conflicting concrete updates */
  49             return false;
  50         if (computeordering()) /* Ordering exists */
  51             return true;
  52         return false;
  53     }
  54
  55     private boolean computeordering() {
  56         /* Build dependency graph between updates */
  57         HashSet graph=new HashSet();
  58         Hashtable mapping=new Hashtable();
  59         for(int i=0;i<updates.size();i++) {
  60             Updates u=(Updates)updates.get(i);
  61             GraphNode gn=new GraphNode(String.valueOf(i),u);
  62             mapping.put(u, gn);
  63             graph.add(gn);
  64         }
  65         for(int i=0;i<updates.size();i++) {
  66             Updates u1=(Updates)updates.get(i);
  67             if (u1.isAbstract())
  68                 continue;
  69             for(int j=0;j<updates.size();j++) {
  70                 Updates u2=(Updates)updates.get(j);
  71                 if (!u2.isExpr())
  72                     continue;
  73                 Descriptor d=u1.getDescriptor();
  74                 Expr subexpr=null;
  75                 Expr intindex=null;
  76
  77                 if (u2.isField()) {
  78                     subexpr=((DotExpr)u2.getLeftExpr()).getExpr();
  79                     intindex=((DotExpr)u2.getLeftExpr()).getIndex();
  80                 }
  81                 if (u2.getRightExpr().usesDescriptor(d)||
  82                     (subexpr!=null&&subexpr.usesDescriptor(d))||
  83                     (intindex!=null&&intindex.usesDescriptor(d))) {
  84                     /* Add edge for dependency */
  85                     GraphNode gn1=(GraphNode) mapping.get(u1);
  86                     GraphNode gn2=(GraphNode) mapping.get(u2);
  87                     GraphNode.Edge e=new GraphNode.Edge("dependency",gn2);
  88                     gn1.addEdge(e);
  89                 }
  90             }
  91         }
  92
  93         if (!GraphNode.DFS.depthFirstSearch(graph))  /* DFS & check for acyclicity */
  94             return false;
  95
  96         TreeSet topologicalsort = new TreeSet(new Comparator() {
  97                 public boolean equals(Object obj) { return false; }
  98                 public int compare(Object o1, Object o2) {
  99                     GraphNode g1 = (GraphNode) o1;
 100                     GraphNode g2 = (GraphNode) o2;
 101                     return g2.getFinishingTime() - g1.getFinishingTime();
 102                 }
 103             });
 104         topologicalsort.addAll(graph);
 105         Vector sortedvector=new Vector();
 106         for(Iterator sort=topologicalsort.iterator();sort.hasNext();) {
 107             GraphNode gn=(GraphNode)sort.next();
 108             sortedvector.add(gn.getOwner());
 109         }
 110         updates=sortedvector; //replace updates with the sorted array
 111         return true;
 112     }
 113
 114     private boolean checkconflicts() {
 115         Set toremove=new HashSet();
 116         for(int i=0;i<updates.size();i++) {
 117             Updates u1=(Updates)updates.get(i);
 118             if (!u1.isAbstract()) {
 119                 Descriptor d=u1.getDescriptor();
 120                 for(int j=0;j<invariants.size();j++) {
 121                     Expr invariant=(Expr)invariants.get(j);
 122                     if (invariant.usesDescriptor(d))
 123                         return false;
 124                 }
 125             }
 126             for(int j=0;j<updates.size();j++) {
 127                 Updates u2=(Updates)updates.get(j);
 128                 if (i==j)
 129                     continue;
 130                 if (u1.isAbstract()||u2.isAbstract())
 131                     continue;  /* Abstract updates are already accounted for by graph */
 132                 if (u1.getDescriptor()!=u2.getDescriptor())
 133                     continue; /* No interference - different descriptors */
 134
 135                 if ((u1.getOpcode()==Opcode.GT||u1.getOpcode()==Opcode.GE)&&
 136                     (u2.getOpcode()==Opcode.GT||u2.getOpcode()==Opcode.GE))
 137                     continue; /* Can be satisfied simultaneously */
 138
 139                 if ((u1.getOpcode()==Opcode.LT||u1.getOpcode()==Opcode.LE)&&
 140                     (u2.getOpcode()==Opcode.LT||u2.getOpcode()==Opcode.LE))
 141                     continue;
 142                 if ((u1.getOpcode()==u2.getOpcode())&&
 143                     u1.isExpr()&&u2.isExpr()&&
 144                     u1.getRightExpr().equals(null, u2.getRightExpr())) {
 145                     /*We'll remove the second occurence*/
 146                     if (i>j)
 147                         toremove.add(u1);
 148                     else
 149                         toremove.add(u2);
 150                     continue;
 151                 }
 152
 153                 /* Handle = or != NULL */
 154                 if ((((u1.getOpcode()==Opcode.EQ)&&(u2.getOpcode()==Opcode.NE))||
 155                      ((u1.getOpcode()==Opcode.NE)&&(u2.getOpcode()==Opcode.EQ)))&&
 156                     (((u1.isExpr()&&u1.getRightExpr().isNull())&&(!u2.isExpr()||u2.getRightExpr().isNonNull()))
 157                      ||((!u1.isExpr()||u1.getRightExpr().isNonNull())&&(u2.isExpr()&&u2.getRightExpr().isNull())))) {
 158                     if (u1.getOpcode()==Opcode.NE)
 159                         toremove.add(u1);
 160                     else
 161                         toremove.add(u2);
 162                     continue;
 163                 }
 164
 165                 /* Handle = and != to different constants */
 166                 if ((((u1.getOpcode()==Opcode.EQ)&&(u2.getOpcode()==Opcode.NE))||
 167                     ((u1.getOpcode()==Opcode.NE)&&(u2.getOpcode()==Opcode.EQ)))&&
 168                     (u1.isExpr()&&u1.getRightExpr() instanceof LiteralExpr)&&
 169                     (u2.isExpr()&&u2.getRightExpr() instanceof LiteralExpr)&&
 170                     !u1.getRightExpr().equals(u2.getRightExpr())) {
 171                     if (u1.getOpcode()==Opcode.NE)
 172                         toremove.add(u1);
 173                     else
 174                         toremove.add(u2);
 175                     continue;
 176                 }
 177
 178                 /* Compatible operations < & <= */
 179                 if (((u1.getOpcode()==Opcode.LT)||(u1.getOpcode()==Opcode.LE))&&
 180                     ((u2.getOpcode()==Opcode.LT)||(u2.getOpcode()==Opcode.LE)))
 181                     continue;
 182
 183                 /* Compatible operations > & >= */
 184                 if (((u1.getOpcode()==Opcode.GT)||(u1.getOpcode()==Opcode.GE))&&
 185                     ((u2.getOpcode()==Opcode.GT)||(u2.getOpcode()==Opcode.GE)))
 186                     continue;
 187                 /* Ranges */
 188
 189                 //XXXXXX: TODO
 190                 /* Equality & Comparisons */
 191                 //XXXXXX: TODO
 192
 193                 return false; /* They interfere */
 194             }
 195         }
 196         updates.removeAll(toremove);
 197         return true;
 198     }
 199
 200     public void addBinding(Binding b) {
 201         bindings.add(b);
 202         binding.put(b.getVar(),b);
 203     }
 204
 205     public int numBindings() {
 206         return bindings.size();
 207     }
 208
 209     public Binding getBinding(int i) {
 210         return (Binding)bindings.get(i);
 211     }
 212
 213     public Binding getBinding(VarDescriptor vd) {
 214         if (binding.containsKey(vd))
 215             return (Binding)binding.get(vd);
 216         else
 217             return null;
 218     }
 219
 220     public void addInvariant(Expr e) {
 221         invariants.add(e);
 222     }
 223
 224     public int numInvariants() {
 225         return invariants.size();
 226     }
 227
 228     public Expr getInvariant(int i) {
 229         return (Expr)invariants.get(i);
 230     }
 231
 232     public void addUpdate(Updates u) {
 233         updates.add(u);
 234     }
 235
 236     public int numUpdates() {
 237         return updates.size();
 238     }
 239     public Updates getUpdate(int i) {
 240         return (Updates)updates.get(i);
 241     }
 242
 243     private MultUpdateNode getMultUpdateNode(boolean negate, Descriptor d, RepairGenerator rg) {
 244         Termination termination=rg.termination;
 245         MultUpdateNode mun=null;
 246         GraphNode gn;
 247         if (negate)
 248             gn=(GraphNode)termination.abstractremove.get(d);
 249         else
 250             gn=(GraphNode)termination.abstractadd.get(d);
 251         TermNode tn=(TermNode)gn.getOwner();
 252         for(Iterator edgeit=gn.edges();edgeit.hasNext();) {
 253             GraphNode gn2=((GraphNode.Edge) edgeit.next()).getTarget();
 254             if (!rg.removed.contains(gn2)) {
 255                 TermNode tn2=(TermNode)gn2.getOwner();
 256                 if (tn2.getType()==TermNode.UPDATE) {
 257                     mun=tn2.getUpdate();
 258                     break;
 259                 }
 260             }
 261         }
 262         if (mun==null)
 263             throw new Error("Can't find update node!");
 264         return mun;
 265     }
 266
 267     public void generate_abstract(CodeWriter cr, Updates u, RepairGenerator rg) {
 268         State state=rg.state;
 269         Expr abstractexpr=u.getLeftExpr();
 270         boolean negated=u.negate;
 271         Descriptor d=null;
 272         Expr left=null;
 273         Expr right=null;
 274         boolean istuple=false;
 275         if (abstractexpr instanceof TupleOfExpr) {
 276             TupleOfExpr toe=(TupleOfExpr) abstractexpr;
 277             d=toe.relation;
 278             left=toe.left;
 279             right=toe.right;
 280             istuple=true;
 281         } else if (abstractexpr instanceof ElementOfExpr) {
 282             ElementOfExpr eoe=(ElementOfExpr) abstractexpr;
 283             d=eoe.set;
 284             left=eoe.element;
 285             istuple=false;
 286         } else {
 287             throw new Error("Unsupported Expr");
 288         }
 289         MultUpdateNode mun=getMultUpdateNode(negated,d,rg);
 290         VarDescriptor leftvar=VarDescriptor.makeNew("leftvar");
 291         VarDescriptor rightvar=VarDescriptor.makeNew("rightvar");
 292         left.generate(cr, leftvar);
 293         if (istuple)
 294             right.generate(cr,rightvar);
 295
 296         if (negated) {
 297             if (istuple) {
 298                 RelationDescriptor rd=(RelationDescriptor)d;
 299                 boolean usageimage=rd.testUsage(RelationDescriptor.IMAGE);
 300                 boolean usageinvimage=rd.testUsage(RelationDescriptor.INVIMAGE);
 301                 if (usageimage)
 302                     cr.outputline(rg.stmodel+"->"+rd.getJustSafeSymbol() + "_hash->remove((int)" + leftvar.getSafeSymbol() + ", (int)" + rightvar.getSafeSymbol() + ");");
 303                 if (usageinvimage)
 304                     cr.outputline(rg.stmodel+"->"+rd.getJustSafeSymbol() + "_hashinv->remove((int)" + rightvar.getSafeSymbol() + ", (int)" + leftvar.getSafeSymbol() + ");");
 305
 306                 for(int i=0;i<state.vRules.size();i++) {
 307                     Rule r=(Rule)state.vRules.get(i);
 308                     if (r.getInclusion().getTargetDescriptors().contains(rd)) {
 309                         for(int j=0;j<mun.numUpdates();j++) {
 310                             UpdateNode un=mun.getUpdate(i);
 311                             if (un.getRule()==r) {
 312                                 /* Update for rule rule r */
 313                                 String name=(String)rg.updatenames.get(un);
 314                                 cr.outputline(rg.strepairtable+"->addrelation("+rd.getNum()+","+r.getNum()+","+leftvar.getSafeSymbol()+","+rightvar.getSafeSymbol()+",(int) &"+name+");");
 315                             }
 316                         }
 317                     }
 318                 }
 319             } else {
 320                 SetDescriptor sd=(SetDescriptor) d;
 321                 cr.outputline(rg.stmodel+"->"+sd.getJustSafeSymbol() + "_hash->remove((int)" + leftvar.getSafeSymbol() + ", (int)" + leftvar.getSafeSymbol() + ");");
 322
 323                 for(int i=0;i<state.vRules.size();i++) {
 324                     Rule r=(Rule)state.vRules.get(i);
 325                     if (r.getInclusion().getTargetDescriptors().contains(sd)) {
 326                         for(int j=0;j<mun.numUpdates();j++) {
 327                             UpdateNode un=mun.getUpdate(j);
 328                             if (un.getRule()==r) {
 329                                 /* Update for rule rule r */
 330                                 String name=(String)rg.updatenames.get(un);
 331                                 cr.outputline(rg.strepairtable+"->addset("+sd.getNum()+","+r.getNum()+","+leftvar.getSafeSymbol()+",(int) &"+name+");");
 332                             }
 333                         }
 334                     }
 335                 }
 336             }
 337         } else {
 338             /* Generate update */
 339             if (istuple) {
 340                 RelationDescriptor rd=(RelationDescriptor) d;
 341                 boolean usageimage=rd.testUsage(RelationDescriptor.IMAGE);
 342                 boolean usageinvimage=rd.testUsage(RelationDescriptor.INVIMAGE);
 343                 if (usageimage)
 344                     cr.outputline(rg.stmodel+"->"+rd.getJustSafeSymbol() + "_hash->add((int)" + leftvar.getSafeSymbol() + ", (int)" + rightvar.getSafeSymbol() + ");");
 345                 if (usageinvimage)
 346                     cr.outputline(rg.stmodel+"->"+rd.getJustSafeSymbol() + "_hashinv->add((int)" + rightvar.getSafeSymbol() + ", (int)" + leftvar.getSafeSymbol() + ");");
 347
 348                 UpdateNode un=mun.getUpdate(0);
 349                 String name=(String)rg.updatenames.get(un);
 350                 cr.outputline(name+"(this,"+rg.stmodel+","+rg.strepairtable+","+leftvar.getSafeSymbol()+","+rightvar.getSafeSymbol()+");");
 351             } else {
 352                 SetDescriptor sd=(SetDescriptor)d;
 353                 cr.outputline(rg.stmodel+"->"+sd.getJustSafeSymbol() + "_hash->add((int)" + leftvar.getSafeSymbol() + ", (int)" + leftvar.getSafeSymbol() + ");");
 354
 355                 UpdateNode un=mun.getUpdate(0);
 356                 /* Update for rule rule r */
 357                 String name=(String)rg.updatenames.get(un);
 358                 cr.outputline(name+"(this,"+rg.stmodel+","+rg.strepairtable+","+leftvar.getSafeSymbol()+");");
 359             }
 360         }
 361     }
 362
 363     public void generate(CodeWriter cr, boolean removal, boolean modify, String slot0, String slot1, String slot2, RepairGenerator rg) {
 364         if (!removal&&!modify)
 365             generate_bindings(cr, slot0,slot1);
 366         for(int i=0;i<updates.size();i++) {
 367             Updates u=(Updates)updates.get(i);
 368             VarDescriptor right=VarDescriptor.makeNew("right");
 369             if (u.getType()==Updates.ABSTRACT) {
 370                 generate_abstract(cr, u, rg);
 371                 return;
 372             }
 373
 374             switch(u.getType()) {
 375             case Updates.EXPR:
 376                 u.getRightExpr().generate(cr,right);
 377                 break;
 378             case Updates.POSITION:
 379             case Updates.ACCESSPATH:
 380                 if (u.getRightPos()==0)
 381                     cr.outputline("int "+right.getSafeSymbol()+"="+slot0+";");
 382                 else if (u.getRightPos()==1)
 383                     cr.outputline("int "+right.getSafeSymbol()+"="+slot1+";");
 384                 else if (u.getRightPos()==2)
 385                     cr.outputline("int "+right.getSafeSymbol()+"="+slot2+";");
 386                 else throw new Error("Error w/ Position");
 387                 break;
 388             default:
 389                 throw new Error();
 390             }
 391
 392             if (u.getType()==Updates.ACCESSPATH) {
 393                 VarDescriptor newright=VarDescriptor.makeNew("right");
 394                 generate_accesspath(cr, right,newright,u);
 395                 right=newright;
 396             }
 397             VarDescriptor left=VarDescriptor.makeNew("left");
 398             u.getLeftExpr().generate(cr,left);
 399             Opcode op=u.getOpcode();
 400             cr.outputline("if (!("+left.getSafeSymbol()+op+right.getSafeSymbol()+"))");
 401             cr.startblock();
 402
 403             if (op==Opcode.GT)
 404                 cr.outputline(right.getSafeSymbol()+"++;");
 405             else if (op==Opcode.GE)
 406                 ;
 407             else if (op==Opcode.EQ)
 408                 ;
 409             else if (op==Opcode.NE)
 410                 cr.outputline(right.getSafeSymbol()+"++;");
 411             else if (op==Opcode.LT)
 412                 cr.outputline(right.getSafeSymbol()+"--;");
 413             else if (op==Opcode.LE)
 414                 ;
 415             else throw new Error();
 416             if (u.isGlobal()) {
 417                 VarDescriptor vd=((VarExpr)u.getLeftExpr()).getVar();
 418                 cr.outputline(vd.getSafeSymbol()+"="+right.getSafeSymbol()+";");
 419             } else if (u.isField()) {
 420                 /* NEED TO FIX */
 421                 Expr subexpr=((DotExpr)u.getLeftExpr()).getExpr();
 422                 Expr intindex=((DotExpr)u.getLeftExpr()).getIndex();
 423                 VarDescriptor subvd=VarDescriptor.makeNew("subexpr");
 424                 VarDescriptor indexvd=VarDescriptor.makeNew("index");
 425                 subexpr.generate(cr,subvd);
 426                 if (intindex!=null)
 427                     intindex.generate(cr,indexvd);
 428                 FieldDescriptor fd=(FieldDescriptor)u.getDescriptor();
 429                 StructureTypeDescriptor std=(StructureTypeDescriptor)subexpr.getType();
 430                 Expr offsetbits = std.getOffsetExpr(fd);
 431                 if (fd instanceof ArrayDescriptor) {
 432                     fd = ((ArrayDescriptor) fd).getField();
 433                 }
 434
 435                 if (intindex != null) {
 436                     Expr basesize = fd.getBaseSizeExpr();
 437                     offsetbits = new OpExpr(Opcode.ADD, offsetbits, new OpExpr(Opcode.MULT, basesize, intindex));
 438                 }
 439                 Expr offsetbytes = new OpExpr(Opcode.SHR, offsetbits,new IntegerLiteralExpr(3));
 440                 Expr byteaddress=new OpExpr(Opcode.ADD, offsetbytes, subexpr);
 441                 VarDescriptor addr=VarDescriptor.makeNew("byteaddress");
 442                 byteaddress.generate(cr,addr);
 443
 444                 if (fd.getType() instanceof ReservedTypeDescriptor && !fd.getPtr()) {
 445                     ReservedTypeDescriptor rtd=(ReservedTypeDescriptor)fd.getType();
 446                     if (rtd==ReservedTypeDescriptor.INT) {
 447                         cr.outputline("*((int *) "+addr.getSafeSymbol()+")="+right.getSafeSymbol()+";");
 448                     } else if (rtd==ReservedTypeDescriptor.SHORT) {
 449                         cr.outputline("*((short *) "+addr.getSafeSymbol()+")="+right.getSafeSymbol()+";");
 450                     } else if (rtd==ReservedTypeDescriptor.BYTE) {
 451                         cr.outputline("*((char *) "+addr.getSafeSymbol()+")="+right.getSafeSymbol()+";");
 452                     } else if (rtd==ReservedTypeDescriptor.BIT) {
 453                         Expr tmp = new OpExpr(Opcode.SHL, offsetbytes, new IntegerLiteralExpr(3));
 454                         Expr offset=new OpExpr(Opcode.SUB, offsetbits, tmp);
 455                         Expr mask=new OpExpr(Opcode.SHL, new IntegerLiteralExpr(1), offset);
 456                         VarDescriptor maskvar=VarDescriptor.makeNew("mask");
 457                         mask.generate(cr,maskvar);
 458                         cr.outputline("*((char *) "+addr.getSafeSymbol()+")|="+maskvar.getSafeSymbol()+";");
 459                         cr.outputline("if (!"+right.getSafeSymbol()+")");
 460                         cr.outputline("*((char *) "+addr.getSafeSymbol()+")^="+maskvar.getSafeSymbol()+";");
 461                     } else throw new Error();
 462                 } else {
 463                     /* Pointer */
 464                     cr.outputline("*((int *) "+addr.getSafeSymbol()+")="+right.getSafeSymbol()+";");
 465                 }
 466             }
 467             cr.endblock();
 468         }
 469     }
 470
 471
 472     private void generate_accesspath(CodeWriter cr, VarDescriptor right, VarDescriptor newright, Updates u) {
 473         Vector dotvector=new Vector();
 474         Expr ptr=u.getRightExpr();
 475         VarExpr rightve=new VarExpr(right);
 476         right.td=ReservedTypeDescriptor.INT;
 477
 478         while(true) {
 479             /* Does something other than a dereference? */
 480             dotvector.add(ptr);
 481             if (ptr instanceof DotExpr)
 482                 ptr=((DotExpr)ptr).left;
 483             else if (ptr instanceof CastExpr)
 484                 ptr=((CastExpr)ptr).getExpr();
 485             if (ptr instanceof VarExpr) {
 486                 /* Finished constructing vector */
 487                 break;
 488             }
 489         }
 490         ArrayAnalysis.AccessPath ap=u.getAccessPath();
 491         VarDescriptor init=VarDescriptor.makeNew("init");
 492         if (ap.isSet()) {
 493             cr.outputline("int "+init.getSafeSymbol()+"="+ap.getSet().getSafeSymbol()+"_hash->firstkey();");
 494             init.td=ap.getSet().getType();
 495         } else {
 496             init=ap.getVar();
 497         }
 498         Expr newexpr=new VarExpr(init);
 499         int apindex=0;
 500         for(int i=dotvector.size()-1;i>=0;i--) {
 501             Expr e=(Expr)dotvector.get(i);
 502             if (e instanceof CastExpr) {
 503                 newexpr.td=e.td;
 504                 newexpr=new CastExpr(((CastExpr)e).getType(),newexpr);
 505             } else if (e instanceof DotExpr) {
 506                 DotExpr de=(DotExpr)e;
 507                 if (de.getField() instanceof ArrayDescriptor) {
 508                     DotExpr de2=new DotExpr(newexpr,de.field,new IntegerLiteralExpr(0));
 509                     de2.fd=de.fd;
 510                     de2.fieldtype=de.fieldtype;
 511                     de2.td=de.td;
 512                     OpExpr offset=new OpExpr(Opcode.SUB,rightve,de2);
 513                     OpExpr index=new OpExpr(Opcode.DIV,offset,de.fieldtype.getSizeExpr());
 514                     if (u.getRightPos()==apindex) {
 515                         index.generate(cr,newright);
 516                         return;
 517                     } else {
 518                         DotExpr de3=new DotExpr(newexpr,de.field,index);
 519                         de3.fd=de.fd;
 520                         de3.td=de.td;
 521                         de3.fieldtype=de.fieldtype;
 522                         newexpr=de3;
 523                     }
 524                 } else {
 525                     DotExpr de2=new DotExpr(newexpr,de.field,null);
 526                     de2.fd=de.fd;
 527                     de2.fieldtype=de.fieldtype;
 528                     de2.td=de.td;
 529                     newexpr=de2;
 530                 }
 531                 apindex++;
 532             } else throw new Error();
 533         }
 534         throw new Error();
 535     }
 536
 537     private void generate_bindings(CodeWriter cr, String slot0, String slot1) {
 538         for(int i=0;i<bindings.size();i++) {
 539             Binding b=(Binding)bindings.get(i);
 540
 541             if (b.getType()==Binding.SEARCH) {
 542                 VarDescriptor vd=b.getVar();
 543                 cr.outputline(vd.getType().getGenerateType().getSafeSymbol()+" "+vd.getSafeSymbol()+"="+b.getSet().getSafeSymbol()+"_hash->firstkey();");
 544             } else if (b.getType()==Binding.CREATE) {
 545                 throw new Error("Creation not supported");
 546                 //              source.generateSourceAlloc(cr,vd,b.getSet());
 547             } else {
 548                 VarDescriptor vd=b.getVar();
 549                 switch(b.getPosition()) {
 550                 case 0:
 551                     cr.outputline(vd.getType().getGenerateType().getSafeSymbol()+" "+vd.getSafeSymbol()+"="+slot0+";");
 552                     break;
 553                 case 1:
 554                     cr.outputline(vd.getType().getGenerateType().getSafeSymbol()+" "+vd.getSafeSymbol()+"="+slot1+";");
 555                     break;
 556                 default:
 557                     throw new Error("Slot >1 doesn't exist.");
 558                 }
 559             }
 560         }
 561     }
 562 }