Robust/src/IR/Flat/BuildFlat.java

   1 package IR.Flat;
   2 import IR.*;
   3 import IR.Tree.*;
   4 import java.util.*;
   5
   6 public class BuildFlat {
   7     State state;
   8     Hashtable temptovar;
   9
  10     public BuildFlat(State st) {
  11         state=st;
  12         temptovar=new Hashtable();
  13     }
  14
  15     public Hashtable getMap() {
  16         return temptovar;
  17     }
  18
  19     public void buildFlat() {
  20         Iterator it=state.getClassSymbolTable().getDescriptorsIterator();
  21         while(it.hasNext()) {
  22             ClassDescriptor cn=(ClassDescriptor)it.next();
  23             flattenClass(cn);
  24         }
  25
  26         Iterator task_it=state.getTaskSymbolTable().getDescriptorsIterator();
  27         while(task_it.hasNext()) {
  28             TaskDescriptor td=(TaskDescriptor)task_it.next();
  29             flattenTask(td);
  30         }
  31     }
  32
  33     private void flattenTask(TaskDescriptor td) {
  34         BlockNode bn=state.getMethodBody(td);
  35         FlatNode fn=flattenBlockNode(bn).getBegin();
  36         FlatFlagActionNode ffan=new FlatFlagActionNode(false);
  37         ffan.addNext(fn);
  38         FlatMethod fm=new FlatMethod(td, ffan);
  39
  40         for(int i=0;i<td.numParameters();i++) {
  41             fm.addParameterTemp(getTempforVar(td.getParameter(i)));
  42         }
  43
  44         /* Flatten Vector of Flag Effects */
  45         Vector flags=td.getFlagEffects();
  46         updateFlagActionNode(ffan,flags);
  47
  48         state.addFlatCode(td,fm);
  49     }
  50
  51
  52     /* This method transforms a vector of FlagEffects into the FlatFlagActionNode */
  53     private void updateFlagActionNode(FlatFlagActionNode ffan, Vector flags) {
  54         for(int i=0;i<flags.size();i++) {
  55             FlagEffects fes=(FlagEffects)flags.get(i);
  56             TempDescriptor flagtemp=getTempforVar(fes.getVar());
  57             for(int j=0;j<fes.numEffects();j++) {
  58                 FlagEffect fe=fes.getEffect(j);
  59                 ffan.addFlagAction(flagtemp, fe.getFlag(), fe.getStatus());
  60             }
  61         }
  62     }
  63
  64     private void flattenClass(ClassDescriptor cn) {
  65         Iterator methodit=cn.getMethods();
  66         while(methodit.hasNext()) {
  67             MethodDescriptor md=(MethodDescriptor)methodit.next();
  68             BlockNode bn=state.getMethodBody(md);
  69             FlatNode fn=flattenBlockNode(bn).getBegin();
  70             FlatMethod fm=new FlatMethod(md, fn);
  71             if (!md.isStatic())
  72                 fm.addParameterTemp(getTempforVar(md.getThis()));
  73             for(int i=0;i<md.numParameters();i++) {
  74                 fm.addParameterTemp(getTempforVar(md.getParameter(i)));
  75             }
  76             System.out.println(fm.printMethod());
  77             state.addFlatCode(md,fm);
  78         }
  79     }
  80
  81     private NodePair flattenBlockNode(BlockNode bn) {
  82         FlatNode begin=null;
  83         FlatNode end=null;
  84         for(int i=0;i<bn.size();i++) {
  85             NodePair np=flattenBlockStatementNode(bn.get(i));
  86             FlatNode np_begin=np.getBegin();
  87             FlatNode np_end=np.getEnd();
  88             if (begin==null) {
  89                 begin=np_begin;
  90             }
  91             if (end==null) {
  92                 end=np_end;
  93             } else {
  94                 end.addNext(np_begin);
  95                 end=np_end;
  96             }
  97         }
  98         if (begin==null) {
  99             end=begin=new FlatNop();
 100         }
 101         return new NodePair(begin,end);
 102     }
 103
 104     private NodePair flattenBlockExpressionNode(BlockExpressionNode en) {
 105         TempDescriptor tmp=TempDescriptor.tempFactory("neverused",en.getExpression().getType());
 106         return flattenExpressionNode(en.getExpression(),tmp);
 107     }
 108
 109     private NodePair flattenCastNode(CastNode cn,TempDescriptor out_temp) {
 110         TempDescriptor tmp=TempDescriptor.tempFactory("tocast",cn.getExpression().getType());
 111         NodePair np=flattenExpressionNode(cn.getExpression(), tmp);
 112         FlatCastNode fcn=new FlatCastNode(cn.getType(), tmp, out_temp);
 113         np.getEnd().addNext(fcn);
 114         return new NodePair(np.getBegin(),fcn);
 115     }
 116
 117     private NodePair flattenLiteralNode(LiteralNode ln,TempDescriptor out_temp) {
 118         FlatLiteralNode fln=new FlatLiteralNode(ln.getType(), ln.getValue(), out_temp);
 119         return new NodePair(fln,fln);
 120     }
 121
 122     private NodePair flattenCreateObjectNode(CreateObjectNode con,TempDescriptor out_temp) {
 123         TypeDescriptor td=con.getType();
 124         if (!td.isArray()) {
 125             FlatNew fn=new FlatNew(td, out_temp);
 126             TempDescriptor[] temps=new TempDescriptor[con.numArgs()];
 127             FlatNode last=fn;
 128
 129             if (con.getFlagEffects()!=null) {
 130                 FlatFlagActionNode ffan=new FlatFlagActionNode(false);
 131                 FlagEffects fes=con.getFlagEffects();
 132                 TempDescriptor flagtemp=out_temp;
 133                 for(int j=0;j<fes.numEffects();j++) {
 134                     FlagEffect fe=fes.getEffect(j);
 135                     ffan.addFlagAction(flagtemp, fe.getFlag(), fe.getStatus());
 136                 }
 137                 last.addNext(ffan);
 138                 last=ffan;
 139             }
 140             //Build arguments
 141             for(int i=0;i<con.numArgs();i++) {
 142                 ExpressionNode en=con.getArg(i);
 143                 TempDescriptor tmp=TempDescriptor.tempFactory("arg",en.getType());
 144                 temps[i]=tmp;
 145                 NodePair np=flattenExpressionNode(en, tmp);
 146                 last.addNext(np.getBegin());
 147                 last=np.getEnd();
 148             }
 149             MethodDescriptor md=con.getConstructor();
 150             //Call to constructor
 151             FlatCall fc=new FlatCall(md, null, out_temp, temps);
 152             last.addNext(fc);
 153             last=fc;
 154             return new NodePair(fn,last);
 155         } else {
 156             FlatNode first=null;
 157             FlatNode last=null;
 158             TempDescriptor[] temps=new TempDescriptor[con.numArgs()];
 159             for (int i=0;i<con.numArgs();i++) {
 160                 ExpressionNode en=con.getArg(i);
 161                 TempDescriptor tmp=TempDescriptor.tempFactory("arg",en.getType());
 162                 temps[i]=tmp;
 163                 NodePair np=flattenExpressionNode(en, tmp);
 164                 if (first==null)
 165                     first=np.getBegin();
 166                 else
 167                     last.addNext(np.getBegin());
 168                 last=np.getEnd();
 169
 170                 TempDescriptor tmp2=(i==0)?
 171                     out_temp:
 172                 TempDescriptor.tempFactory("arg",en.getType());
 173             }
 174             FlatNew fn=new FlatNew(td, out_temp, temps[0]);
 175             last.addNext(fn);
 176             if (temps.length>1) {
 177                 NodePair np=generateNewArrayLoop(temps, td.dereference(), out_temp, 0);
 178                 fn.addNext(np.getBegin());
 179                 return new NodePair(first,np.getEnd());
 180             } else
 181                 return new NodePair(first, fn);
 182         }
 183     }
 184
 185     private NodePair generateNewArrayLoop(TempDescriptor[] temparray, TypeDescriptor td, TempDescriptor tmp, int i) {
 186         TempDescriptor index=TempDescriptor.tempFactory("index",new TypeDescriptor(TypeDescriptor.INT));
 187         TempDescriptor tmpone=TempDescriptor.tempFactory("index",new TypeDescriptor(TypeDescriptor.INT));
 188         FlatNop fnop=new FlatNop();//last node
 189
 190         //index=0
 191         FlatLiteralNode fln=new FlatLiteralNode(index.getType(),new Integer(0),index);
 192         //tmpone=1
 193         FlatLiteralNode fln2=new FlatLiteralNode(tmpone.getType(),new Integer(1),tmpone);
 194
 195         TempDescriptor tmpbool=TempDescriptor.tempFactory("comp",new TypeDescriptor(TypeDescriptor.BOOLEAN));
 196
 197         FlatOpNode fcomp=new FlatOpNode(tmpbool,index,temparray[i],new Operation(Operation.LT));
 198         FlatCondBranch fcb=new FlatCondBranch(tmpbool);
 199         //is index<temp[i]
 200         TempDescriptor new_tmp=TempDescriptor.tempFactory("tmp",td);
 201         FlatNew fn=new FlatNew(td, new_tmp, temparray[i+1]);
 202         FlatSetElementNode fsen=new FlatSetElementNode(tmp,index,new_tmp);
 203         // index=index+1
 204         FlatOpNode fon=new FlatOpNode(index,index,tmpone,new Operation(Operation.ADD));
 205         //jump out
 206         fln.addNext(fln2);
 207         fln2.addNext(fcomp);
 208         fcomp.addNext(fcb);
 209         fcb.addTrueNext(fn);
 210         fcb.addFalseNext(fnop);
 211         fn.addNext(fsen);
 212         //Recursive call here
 213         if ((i+2)<temparray.length) {
 214             NodePair np2=generateNewArrayLoop(temparray, td.dereference(), new_tmp, i+1);
 215             fsen.addNext(np2.getBegin());
 216             np2.getEnd().addNext(fon);
 217         } else {
 218             fsen.addNext(fon);
 219         }
 220         fon.addNext(fcomp);
 221         return new NodePair(fln, fnop);
 222     }
 223
 224     private NodePair flattenMethodInvokeNode(MethodInvokeNode min,TempDescriptor out_temp) {
 225         TempDescriptor[] temps=new TempDescriptor[min.numArgs()];
 226         FlatNode first=null;
 227         FlatNode last=null;
 228         TempDescriptor thisarg=null;
 229
 230         if (min.getExpression()!=null) {
 231             thisarg=TempDescriptor.tempFactory("thisarg",min.getExpression().getType());
 232             NodePair np=flattenExpressionNode(min.getExpression(),thisarg);
 233             first=np.getBegin();
 234             last=np.getEnd();
 235         }
 236
 237         //Build arguments
 238         for(int i=0;i<min.numArgs();i++) {
 239             ExpressionNode en=min.getArg(i);
 240             TempDescriptor td=TempDescriptor.tempFactory("arg",en.getType());
 241             temps[i]=td;
 242             NodePair np=flattenExpressionNode(en, td);
 243             if (first==null)
 244                 first=np.getBegin();
 245             else
 246                 last.addNext(np.getBegin());
 247             last=np.getEnd();
 248         }
 249
 250         MethodDescriptor md=min.getMethod();
 251
 252         //Call to constructor
 253
 254         FlatCall fc;
 255         if(md.getReturnType()==null||md.getReturnType().isVoid())
 256             fc=new FlatCall(md, null, thisarg, temps);
 257         else
 258             fc=new FlatCall(md, out_temp, thisarg, temps);
 259         if (first==null) {
 260             first=fc;
 261         } else
 262             last.addNext(fc);
 263         return new NodePair(first,fc);
 264     }
 265
 266     private NodePair flattenFieldAccessNode(FieldAccessNode fan,TempDescriptor out_temp) {
 267         TempDescriptor tmp=TempDescriptor.tempFactory("temp",fan.getExpression().getType());
 268         NodePair npe=flattenExpressionNode(fan.getExpression(),tmp);
 269         FlatFieldNode fn=new FlatFieldNode(fan.getField(),tmp,out_temp);
 270         npe.getEnd().addNext(fn);
 271         return new NodePair(npe.getBegin(),fn);
 272     }
 273
 274     private NodePair flattenArrayAccessNode(ArrayAccessNode aan,TempDescriptor out_temp) {
 275         TempDescriptor tmp=TempDescriptor.tempFactory("temp",aan.getExpression().getType());
 276         TempDescriptor tmpindex=TempDescriptor.tempFactory("temp",aan.getIndex().getType());
 277         NodePair npe=flattenExpressionNode(aan.getExpression(),tmp);
 278         NodePair npi=flattenExpressionNode(aan.getIndex(),tmpindex);
 279         FlatElementNode fn=new FlatElementNode(tmp,tmpindex,out_temp);
 280         npe.getEnd().addNext(npi.getBegin());
 281         npi.getEnd().addNext(fn);
 282         return new NodePair(npe.getBegin(),fn);
 283     }
 284
 285     private NodePair flattenAssignmentNode(AssignmentNode an,TempDescriptor out_temp) {
 286         // Three cases:
 287         // left side is variable
 288         // left side is field
 289         // left side is array
 290
 291         Operation base=an.getOperation().getBaseOp();
 292         TempDescriptor src_tmp=TempDescriptor.tempFactory("src",an.getSrc().getType());
 293         NodePair np_src=flattenExpressionNode(an.getSrc(),src_tmp);
 294         FlatNode last=np_src.getEnd();
 295         if (base!=null) {
 296             TempDescriptor src_tmp2=TempDescriptor.tempFactory("tmp", an.getDest().getType());
 297             NodePair np_dst_init=flattenExpressionNode(an.getDest(),src_tmp2);
 298             last.addNext(np_dst_init.getBegin());
 299             TempDescriptor dst_tmp=TempDescriptor.tempFactory("dst_tmp",an.getDest().getType());
 300             FlatOpNode fon=new FlatOpNode(dst_tmp, src_tmp,src_tmp2, base);
 301             np_dst_init.getEnd().addNext(fon);
 302             last=fon;
 303             src_tmp=dst_tmp;
 304         }
 305
 306         if (an.getDest().kind()==Kind.FieldAccessNode) {
 307             //We are assigning an object field
 308             FieldAccessNode fan=(FieldAccessNode)an.getDest();
 309             ExpressionNode en=fan.getExpression();
 310             TempDescriptor dst_tmp=TempDescriptor.tempFactory("dst",en.getType());
 311             NodePair np_baseexp=flattenExpressionNode(en, dst_tmp);
 312             last.addNext(np_baseexp.getBegin());
 313             FlatSetFieldNode fsfn=new FlatSetFieldNode(dst_tmp, fan.getField(), src_tmp);
 314             np_baseexp.getEnd().addNext(fsfn);
 315             FlatOpNode fon2=new FlatOpNode(out_temp, src_tmp, null, new Operation(Operation.ASSIGN));
 316             fsfn.addNext(fon2);
 317             return new NodePair(np_src.getBegin(), fon2);
 318         } else if (an.getDest().kind()==Kind.ArrayAccessNode) {
 319             //We are assigning an array element
 320             ArrayAccessNode aan=(ArrayAccessNode)an.getDest();
 321             ExpressionNode en=aan.getExpression();
 322             ExpressionNode enindex=aan.getIndex();
 323             TempDescriptor dst_tmp=TempDescriptor.tempFactory("dst",en.getType());
 324             TempDescriptor index_tmp=TempDescriptor.tempFactory("index",enindex.getType());
 325             NodePair np_baseexp=flattenExpressionNode(en, dst_tmp);
 326             NodePair np_indexexp=flattenExpressionNode(enindex, index_tmp);
 327             last.addNext(np_baseexp.getBegin());
 328             np_baseexp.getEnd().addNext(np_indexexp.getBegin());
 329             FlatSetElementNode fsen=new FlatSetElementNode(dst_tmp, index_tmp, src_tmp);
 330             np_indexexp.getEnd().addNext(fsen);
 331             FlatOpNode fon2=new FlatOpNode(out_temp, src_tmp, null, new Operation(Operation.ASSIGN));
 332             fsen.addNext(fon2);
 333             return new NodePair(np_src.getBegin(), fon2);
 334         } else if (an.getDest().kind()==Kind.NameNode) {
 335             //We could be assigning a field or variable
 336             NameNode nn=(NameNode)an.getDest();
 337             if (nn.getExpression()!=null) {
 338                 //It is a field
 339                 FieldAccessNode fan=(FieldAccessNode)nn.getExpression();
 340                 ExpressionNode en=fan.getExpression();
 341                 TempDescriptor dst_tmp=TempDescriptor.tempFactory("dst",en.getType());
 342                 NodePair np_baseexp=flattenExpressionNode(en, dst_tmp);
 343                 last.addNext(np_baseexp.getBegin());
 344                 FlatSetFieldNode fsfn=new FlatSetFieldNode(dst_tmp, fan.getField(), src_tmp);
 345                 np_baseexp.getEnd().addNext(fsfn);
 346                 FlatOpNode fon2=new FlatOpNode(out_temp, src_tmp, null, new Operation(Operation.ASSIGN));
 347                 fsfn.addNext(fon2);
 348                 return new NodePair(np_src.getBegin(), fon2);
 349             } else {
 350                 if (nn.getField()!=null) {
 351                     //It is a field
 352                     FlatSetFieldNode fsfn=new FlatSetFieldNode(getTempforVar(nn.getVar()), nn.getField(), src_tmp);
 353                     last.addNext(fsfn);
 354                     FlatOpNode fon2=new FlatOpNode(out_temp, src_tmp, null, new Operation(Operation.ASSIGN));
 355                     fsfn.addNext(fon2);
 356                     return new NodePair(np_src.getBegin(), fon2);
 357                 } else {
 358                     //It is a variable
 359                     FlatOpNode fon=new FlatOpNode(getTempforVar(nn.getVar()), src_tmp, null, new Operation(Operation.ASSIGN));
 360                     last.addNext(fon);
 361                     FlatOpNode fon2=new FlatOpNode(out_temp, src_tmp, null, new Operation(Operation.ASSIGN));
 362                     fon.addNext(fon2);
 363                     return new NodePair(np_src.getBegin(),fon2);
 364                 }
 365             }
 366         }
 367         throw new Error();
 368     }
 369
 370     private NodePair flattenNameNode(NameNode nn,TempDescriptor out_temp) {
 371         if (nn.getExpression()!=null) {
 372             /* Hack - use subtree instead */
 373             return flattenExpressionNode(nn.getExpression(),out_temp);
 374         } else if (nn.getField()!=null) {
 375             TempDescriptor tmp=getTempforVar(nn.getVar());
 376             FlatFieldNode ffn=new FlatFieldNode(nn.getField(), tmp, out_temp);
 377             return new NodePair(ffn,ffn);
 378         } else {
 379             TempDescriptor tmp=getTempforVar(nn.getVar());
 380             FlatOpNode fon=new FlatOpNode(out_temp, tmp, null, new Operation(Operation.ASSIGN));
 381             return new NodePair(fon,fon);
 382         }
 383     }
 384
 385     private NodePair flattenOpNode(OpNode on,TempDescriptor out_temp) {
 386         TempDescriptor temp_left=TempDescriptor.tempFactory("leftop",on.getLeft().getType());
 387         TempDescriptor temp_right=null;
 388
 389         Operation op=on.getOp();
 390         if (op.getOp()==Operation.POSTINC||
 391             op.getOp()==Operation.POSTDEC||
 392             op.getOp()==Operation.PREINC||
 393             op.getOp()==Operation.PREDEC) {
 394             LiteralNode ln=new LiteralNode("int",new Integer(1));
 395             ln.setType(new TypeDescriptor(TypeDescriptor.INT));
 396
 397             AssignmentNode an=new AssignmentNode(on.getLeft(),
 398                                                  new OpNode(on.getLeft(),ln,
 399                                                             new Operation((op.getOp()==Operation.POSTINC||op.getOp()==Operation.PREINC)?Operation.PLUS:Operation.MINUS))
 400                                                  );
 401             if (op.getOp()==Operation.POSTINC||
 402                 op.getOp()==Operation.POSTDEC) {
 403                 //Can't do, this could have side effects
 404                 NodePair left=flattenExpressionNode(on.getLeft(),out_temp);
 405                 NodePair assign=flattenAssignmentNode(an,temp_left);
 406                 left.getEnd().addNext(assign.getBegin());
 407                 return new NodePair(left.getBegin(),assign.getEnd());
 408             } else {
 409                 NodePair assign=flattenAssignmentNode(an,out_temp);
 410                 return assign;
 411             }
 412         }
 413
 414         NodePair left=flattenExpressionNode(on.getLeft(),temp_left);
 415         NodePair right;
 416         if (on.getRight()!=null) {
 417             temp_right=TempDescriptor.tempFactory("rightop",on.getRight().getType());
 418             right=flattenExpressionNode(on.getRight(),temp_right);
 419         } else {
 420             FlatNop nop=new FlatNop();
 421             right=new NodePair(nop,nop);
 422         }
 423
 424         if (op.getOp()==Operation.LOGIC_OR) {
 425             /* Need to do shortcircuiting */
 426             FlatCondBranch fcb=new FlatCondBranch(temp_left);
 427             FlatOpNode fon1=new FlatOpNode(out_temp,temp_left,null,new Operation(Operation.ASSIGN));
 428             FlatOpNode fon2=new FlatOpNode(out_temp,temp_right,null,new Operation(Operation.ASSIGN));
 429             FlatNop fnop=new FlatNop();
 430             left.getEnd().addNext(fcb);
 431             fcb.addFalseNext(right.getBegin());
 432             right.getEnd().addNext(fon2);
 433             fon2.addNext(fnop);
 434             fcb.addTrueNext(fon1);
 435             fon1.addNext(fnop);
 436             return new NodePair(left.getBegin(), fnop);
 437         } else if (op.getOp()==Operation.LOGIC_AND) {
 438             /* Need to do shortcircuiting */
 439             FlatCondBranch fcb=new FlatCondBranch(temp_left);
 440             FlatOpNode fon1=new FlatOpNode(out_temp,temp_left,null,new Operation(Operation.ASSIGN));
 441             FlatOpNode fon2=new FlatOpNode(out_temp,temp_right,null,new Operation(Operation.ASSIGN));
 442             FlatNop fnop=new FlatNop();
 443             left.getEnd().addNext(fcb);
 444             fcb.addTrueNext(right.getBegin());
 445             right.getEnd().addNext(fon2);
 446             fon2.addNext(fnop);
 447             fcb.addFalseNext(fon1);
 448             fon1.addNext(fnop);
 449             return new NodePair(left.getBegin(), fnop);
 450         }
 451
 452         FlatOpNode fon=new FlatOpNode(out_temp,temp_left,temp_right,op);
 453         left.getEnd().addNext(right.getBegin());
 454         right.getEnd().addNext(fon);
 455         return new NodePair(left.getBegin(),fon);
 456     }
 457
 458     private NodePair flattenExpressionNode(ExpressionNode en, TempDescriptor out_temp) {
 459         switch(en.kind()) {
 460         case Kind.AssignmentNode:
 461             return flattenAssignmentNode((AssignmentNode)en,out_temp);
 462         case Kind.CastNode:
 463             return flattenCastNode((CastNode)en,out_temp);
 464         case Kind.CreateObjectNode:
 465             return flattenCreateObjectNode((CreateObjectNode)en,out_temp);
 466         case Kind.FieldAccessNode:
 467             return flattenFieldAccessNode((FieldAccessNode)en,out_temp);
 468         case Kind.ArrayAccessNode:
 469             return flattenArrayAccessNode((ArrayAccessNode)en,out_temp);
 470         case Kind.LiteralNode:
 471             return flattenLiteralNode((LiteralNode)en,out_temp);
 472         case Kind.MethodInvokeNode:
 473             return flattenMethodInvokeNode((MethodInvokeNode)en,out_temp);
 474         case Kind.NameNode:
 475             return flattenNameNode((NameNode)en,out_temp);
 476         case Kind.OpNode:
 477             return flattenOpNode((OpNode)en,out_temp);
 478         }
 479         throw new Error();
 480     }
 481
 482     private NodePair flattenDeclarationNode(DeclarationNode dn) {
 483         VarDescriptor vd=dn.getVarDescriptor();
 484         TempDescriptor td=getTempforVar(vd);
 485         if (dn.getExpression()!=null)
 486             return flattenExpressionNode(dn.getExpression(),td);
 487         else {
 488             FlatNop fn=new FlatNop();
 489             return new NodePair(fn,fn);
 490         }
 491     }
 492
 493     private TempDescriptor getTempforVar(VarDescriptor vd) {
 494         if (temptovar.containsKey(vd))
 495             return (TempDescriptor)temptovar.get(vd);
 496         else {
 497             TempDescriptor td=TempDescriptor.tempFactory(vd.getName(),vd.getType());
 498             temptovar.put(vd,td);
 499             return td;
 500         }
 501     }
 502
 503     private NodePair flattenIfStatementNode(IfStatementNode isn) {
 504         TempDescriptor cond_temp=TempDescriptor.tempFactory("condition",new TypeDescriptor(TypeDescriptor.BOOLEAN));
 505         NodePair cond=flattenExpressionNode(isn.getCondition(),cond_temp);
 506         FlatCondBranch fcb=new FlatCondBranch(cond_temp);
 507         NodePair true_np=flattenBlockNode(isn.getTrueBlock());
 508         NodePair false_np;
 509         FlatNop nopend=new FlatNop();
 510
 511         if (isn.getFalseBlock()!=null)
 512             false_np=flattenBlockNode(isn.getFalseBlock());
 513         else {
 514             FlatNop nop=new FlatNop();
 515             false_np=new NodePair(nop,nop);
 516         }
 517
 518         cond.getEnd().addNext(fcb);
 519         fcb.addTrueNext(true_np.getBegin());
 520         fcb.addFalseNext(false_np.getBegin());
 521         true_np.getEnd().addNext(nopend);
 522         false_np.getEnd().addNext(nopend);
 523         return new NodePair(cond.getBegin(), nopend);
 524     }
 525
 526     private NodePair flattenLoopNode(LoopNode ln) {
 527         if (ln.getType()==LoopNode.FORLOOP) {
 528             NodePair initializer=flattenBlockNode(ln.getInitializer());
 529             TempDescriptor cond_temp=TempDescriptor.tempFactory("condition", new TypeDescriptor(TypeDescriptor.BOOLEAN));
 530             NodePair condition=flattenExpressionNode(ln.getCondition(),cond_temp);
 531             NodePair update=flattenBlockNode(ln.getUpdate());
 532             NodePair body=flattenBlockNode(ln.getBody());
 533             FlatNode begin=initializer.getBegin();
 534             FlatCondBranch fcb=new FlatCondBranch(cond_temp);
 535             FlatNop nopend=new FlatNop();
 536
 537             initializer.getEnd().addNext(condition.getBegin());
 538             body.getEnd().addNext(update.getBegin());
 539             update.getEnd().addNext(condition.getBegin());
 540             condition.getEnd().addNext(fcb);
 541             fcb.addFalseNext(nopend);
 542             fcb.addTrueNext(body.getBegin());
 543             return new NodePair(begin,nopend);
 544         } else if (ln.getType()==LoopNode.WHILELOOP) {
 545             TempDescriptor cond_temp=TempDescriptor.tempFactory("condition", new TypeDescriptor(TypeDescriptor.BOOLEAN));
 546             NodePair condition=flattenExpressionNode(ln.getCondition(),cond_temp);
 547             NodePair body=flattenBlockNode(ln.getBody());
 548             FlatNode begin=condition.getBegin();
 549             FlatCondBranch fcb=new FlatCondBranch(cond_temp);
 550             FlatNop nopend=new FlatNop();
 551
 552             body.getEnd().addNext(condition.getBegin());
 553             condition.getEnd().addNext(fcb);
 554             fcb.addFalseNext(nopend);
 555             fcb.addTrueNext(body.getBegin());
 556             return new NodePair(begin,nopend);
 557         } else if (ln.getType()==LoopNode.DOWHILELOOP) {
 558             TempDescriptor cond_temp=TempDescriptor.tempFactory("condition", new TypeDescriptor(TypeDescriptor.BOOLEAN));
 559             NodePair condition=flattenExpressionNode(ln.getCondition(),cond_temp);
 560             NodePair body=flattenBlockNode(ln.getBody());
 561             FlatNode begin=body.getBegin();
 562             FlatCondBranch fcb=new FlatCondBranch(cond_temp);
 563             FlatNop nopend=new FlatNop();
 564
 565             body.getEnd().addNext(condition.getBegin());
 566             condition.getEnd().addNext(fcb);
 567             fcb.addFalseNext(nopend);
 568             fcb.addTrueNext(body.getBegin());
 569             return new NodePair(begin,nopend);
 570         } else throw new Error();
 571     }
 572
 573     private NodePair flattenReturnNode(ReturnNode rntree) {
 574         TempDescriptor retval=null;
 575         NodePair cond=null;
 576         if (rntree.getReturnExpression()!=null) {
 577             retval=TempDescriptor.tempFactory("ret_value", rntree.getReturnExpression().getType());
 578             cond=flattenExpressionNode(rntree.getReturnExpression(),retval);
 579         }
 580
 581         FlatReturnNode rnflat=new FlatReturnNode(retval);
 582
 583         if (cond!=null) {
 584             cond.getEnd().addNext(rnflat);
 585             return new NodePair(cond.getBegin(),rnflat);
 586         } else
 587             return new NodePair(rnflat,rnflat);
 588     }
 589
 590     private NodePair flattenTaskExitNode(TaskExitNode ten) {
 591         FlatFlagActionNode ffan=new FlatFlagActionNode(true);
 592         updateFlagActionNode(ffan, ten.getFlagEffects());
 593         return new NodePair(ffan, ffan);
 594     }
 595
 596     private NodePair flattenSubBlockNode(SubBlockNode sbn) {
 597         return flattenBlockNode(sbn.getBlockNode());
 598     }
 599
 600     private NodePair flattenBlockStatementNode(BlockStatementNode bsn) {
 601         switch(bsn.kind()) {
 602         case Kind.BlockExpressionNode:
 603             return flattenBlockExpressionNode((BlockExpressionNode)bsn);
 604
 605         case Kind.DeclarationNode:
 606             return flattenDeclarationNode((DeclarationNode)bsn);
 607
 608         case Kind.IfStatementNode:
 609             return flattenIfStatementNode((IfStatementNode)bsn);
 610
 611         case Kind.LoopNode:
 612             return flattenLoopNode((LoopNode)bsn);
 613
 614         case Kind.ReturnNode:
 615             return flattenReturnNode((IR.Tree.ReturnNode)bsn);
 616
 617         case Kind.TaskExitNode:
 618             return flattenTaskExitNode((IR.Tree.TaskExitNode)bsn);
 619
 620         case Kind.SubBlockNode:
 621             return flattenSubBlockNode((SubBlockNode)bsn);
 622
 623         }
 624         throw new Error();
 625     }
 626 }