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();
  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             //Build arguments
 129             for(int i=0;i<con.numArgs();i++) {
 130                 ExpressionNode en=con.getArg(i);
 131                 TempDescriptor tmp=TempDescriptor.tempFactory("arg",en.getType());
 132                 temps[i]=tmp;
 133                 NodePair np=flattenExpressionNode(en, tmp);
 134                 last.addNext(np.getBegin());
 135                 last=np.getEnd();
 136             }
 137             MethodDescriptor md=con.getConstructor();
 138             //Call to constructor
 139             FlatCall fc=new FlatCall(md, null, out_temp, temps);
 140             last.addNext(fc);
 141             return new NodePair(fn,fc);
 142         } else {
 143             FlatNode first=null;
 144             FlatNode last=null;
 145             TempDescriptor[] temps=new TempDescriptor[con.numArgs()];
 146             for (int i=0;i<con.numArgs();i++) {
 147                 ExpressionNode en=con.getArg(i);
 148                 TempDescriptor tmp=TempDescriptor.tempFactory("arg",en.getType());
 149                 temps[i]=tmp;
 150                 NodePair np=flattenExpressionNode(en, tmp);
 151                 if (first==null)
 152                     first=np.getBegin();
 153                 else
 154                     last.addNext(np.getBegin());
 155                 last=np.getEnd();
 156
 157                 TempDescriptor tmp2=(i==0)?
 158                     out_temp:
 159                 TempDescriptor.tempFactory("arg",en.getType());
 160             }
 161             FlatNew fn=new FlatNew(td, out_temp, temps[0]);
 162             last.addNext(fn);
 163             if (temps.length>1) {
 164                 NodePair np=generateNewArrayLoop(temps, td.dereference(), out_temp, 0);
 165                 fn.addNext(np.getBegin());
 166                 return new NodePair(first,np.getEnd());
 167             } else
 168                 return new NodePair(first, fn);
 169         }
 170     }
 171
 172     private NodePair generateNewArrayLoop(TempDescriptor[] temparray, TypeDescriptor td, TempDescriptor tmp, int i) {
 173         TempDescriptor index=TempDescriptor.tempFactory("index",new TypeDescriptor(TypeDescriptor.INT));
 174         TempDescriptor tmpone=TempDescriptor.tempFactory("index",new TypeDescriptor(TypeDescriptor.INT));
 175         FlatNop fnop=new FlatNop();//last node
 176
 177         //index=0
 178         FlatLiteralNode fln=new FlatLiteralNode(index.getType(),new Integer(0),index);
 179         //tmpone=1
 180         FlatLiteralNode fln2=new FlatLiteralNode(tmpone.getType(),new Integer(1),tmpone);
 181
 182         TempDescriptor tmpbool=TempDescriptor.tempFactory("comp",new TypeDescriptor(TypeDescriptor.BOOLEAN));
 183
 184         FlatOpNode fcomp=new FlatOpNode(tmpbool,index,temparray[i],new Operation(Operation.LT));
 185         FlatCondBranch fcb=new FlatCondBranch(tmpbool);
 186         //is index<temp[i]
 187         TempDescriptor new_tmp=TempDescriptor.tempFactory("tmp",td);
 188         FlatNew fn=new FlatNew(td, new_tmp, temparray[i+1]);
 189         FlatSetElementNode fsen=new FlatSetElementNode(tmp,index,new_tmp);
 190         // index=index+1
 191         FlatOpNode fon=new FlatOpNode(index,index,tmpone,new Operation(Operation.ADD));
 192         //jump out
 193         fln.addNext(fln2);
 194         fln2.addNext(fcomp);
 195         fcomp.addNext(fcb);
 196         fcb.addTrueNext(fn);
 197         fcb.addFalseNext(fnop);
 198         fn.addNext(fsen);
 199         //Recursive call here
 200         if ((i+2)<temparray.length) {
 201             NodePair np2=generateNewArrayLoop(temparray, td.dereference(), new_tmp, i+1);
 202             fsen.addNext(np2.getBegin());
 203             np2.getEnd().addNext(fon);
 204         } else {
 205             fsen.addNext(fon);
 206         }
 207         fon.addNext(fcomp);
 208         return new NodePair(fln, fnop);
 209     }
 210
 211     private NodePair flattenMethodInvokeNode(MethodInvokeNode min,TempDescriptor out_temp) {
 212         TempDescriptor[] temps=new TempDescriptor[min.numArgs()];
 213         FlatNode first=null;
 214         FlatNode last=null;
 215         TempDescriptor thisarg=null;
 216
 217         if (min.getExpression()!=null) {
 218             thisarg=TempDescriptor.tempFactory("thisarg",min.getExpression().getType());
 219             NodePair np=flattenExpressionNode(min.getExpression(),thisarg);
 220             first=np.getBegin();
 221             last=np.getEnd();
 222         }
 223
 224         //Build arguments
 225         for(int i=0;i<min.numArgs();i++) {
 226             ExpressionNode en=min.getArg(i);
 227             TempDescriptor td=TempDescriptor.tempFactory("arg",en.getType());
 228             temps[i]=td;
 229             NodePair np=flattenExpressionNode(en, td);
 230             if (first==null)
 231                 first=np.getBegin();
 232             else
 233                 last.addNext(np.getBegin());
 234             last=np.getEnd();
 235         }
 236
 237         MethodDescriptor md=min.getMethod();
 238
 239         //Call to constructor
 240
 241         FlatCall fc;
 242         if(md.getReturnType()==null||md.getReturnType().isVoid())
 243             fc=new FlatCall(md, null, thisarg, temps);
 244         else
 245             fc=new FlatCall(md, out_temp, thisarg, temps);
 246         if (first==null) {
 247             first=fc;
 248         } else
 249             last.addNext(fc);
 250         return new NodePair(first,fc);
 251     }
 252
 253     private NodePair flattenFieldAccessNode(FieldAccessNode fan,TempDescriptor out_temp) {
 254         TempDescriptor tmp=TempDescriptor.tempFactory("temp",fan.getExpression().getType());
 255         NodePair npe=flattenExpressionNode(fan.getExpression(),tmp);
 256         FlatFieldNode fn=new FlatFieldNode(fan.getField(),tmp,out_temp);
 257         npe.getEnd().addNext(fn);
 258         return new NodePair(npe.getBegin(),fn);
 259     }
 260
 261     private NodePair flattenArrayAccessNode(ArrayAccessNode aan,TempDescriptor out_temp) {
 262         TempDescriptor tmp=TempDescriptor.tempFactory("temp",aan.getExpression().getType());
 263         TempDescriptor tmpindex=TempDescriptor.tempFactory("temp",aan.getIndex().getType());
 264         NodePair npe=flattenExpressionNode(aan.getExpression(),tmp);
 265         NodePair npi=flattenExpressionNode(aan.getIndex(),tmpindex);
 266         FlatElementNode fn=new FlatElementNode(tmp,tmpindex,out_temp);
 267         npe.getEnd().addNext(npi.getBegin());
 268         npi.getEnd().addNext(fn);
 269         return new NodePair(npe.getBegin(),fn);
 270     }
 271
 272     private NodePair flattenAssignmentNode(AssignmentNode an,TempDescriptor out_temp) {
 273         // Two cases:
 274         // left side is variable
 275         // left side is field
 276
 277         Operation base=an.getOperation().getBaseOp();
 278         TempDescriptor src_tmp=TempDescriptor.tempFactory("src",an.getSrc().getType());
 279         NodePair np_src=flattenExpressionNode(an.getSrc(),src_tmp);
 280         FlatNode last=np_src.getEnd();
 281         if (base!=null) {
 282             TempDescriptor src_tmp2=TempDescriptor.tempFactory("tmp", an.getDest().getType());
 283             NodePair np_dst_init=flattenExpressionNode(an.getDest(),src_tmp2);
 284             last.addNext(np_dst_init.getBegin());
 285             TempDescriptor dst_tmp=TempDescriptor.tempFactory("dst_tmp",an.getDest().getType());
 286             FlatOpNode fon=new FlatOpNode(dst_tmp, src_tmp,src_tmp2, base);
 287             np_dst_init.getEnd().addNext(fon);
 288             last=fon;
 289             src_tmp=dst_tmp;
 290         }
 291
 292         if (an.getDest().kind()==Kind.FieldAccessNode) {
 293             FieldAccessNode fan=(FieldAccessNode)an.getDest();
 294             ExpressionNode en=fan.getExpression();
 295             TempDescriptor dst_tmp=TempDescriptor.tempFactory("dst",en.getType());
 296             NodePair np_baseexp=flattenExpressionNode(en, dst_tmp);
 297             last.addNext(np_baseexp.getBegin());
 298             FlatSetFieldNode fsfn=new FlatSetFieldNode(dst_tmp, fan.getField(), src_tmp);
 299             np_baseexp.getEnd().addNext(fsfn);
 300             return new NodePair(np_src.getBegin(), fsfn);
 301         } else if (an.getDest().kind()==Kind.ArrayAccessNode) {
 302             ArrayAccessNode aan=(ArrayAccessNode)an.getDest();
 303             ExpressionNode en=aan.getExpression();
 304             ExpressionNode enindex=aan.getIndex();
 305             TempDescriptor dst_tmp=TempDescriptor.tempFactory("dst",en.getType());
 306             TempDescriptor index_tmp=TempDescriptor.tempFactory("index",enindex.getType());
 307             NodePair np_baseexp=flattenExpressionNode(en, dst_tmp);
 308             NodePair np_indexexp=flattenExpressionNode(enindex, index_tmp);
 309             last.addNext(np_baseexp.getBegin());
 310             np_baseexp.getEnd().addNext(np_indexexp.getBegin());
 311             FlatSetElementNode fsen=new FlatSetElementNode(dst_tmp, index_tmp, src_tmp);
 312             np_indexexp.getEnd().addNext(fsen);
 313             return new NodePair(np_src.getBegin(), fsen);
 314         } else if (an.getDest().kind()==Kind.NameNode) {
 315             NameNode nn=(NameNode)an.getDest();
 316             if (nn.getExpression()!=null) {
 317                 FieldAccessNode fan=(FieldAccessNode)nn.getExpression();
 318                 ExpressionNode en=fan.getExpression();
 319                 TempDescriptor dst_tmp=TempDescriptor.tempFactory("dst",en.getType());
 320                 NodePair np_baseexp=flattenExpressionNode(en, dst_tmp);
 321                 last.addNext(np_baseexp.getBegin());
 322                 FlatSetFieldNode fsfn=new FlatSetFieldNode(dst_tmp, fan.getField(), src_tmp);
 323                 np_baseexp.getEnd().addNext(fsfn);
 324                 return new NodePair(np_src.getBegin(), fsfn);
 325             } else {
 326                 if (nn.getField()!=null) {
 327                     FlatSetFieldNode fsfn=new FlatSetFieldNode(getTempforVar(nn.getVar()), nn.getField(), src_tmp);
 328                     last.addNext(fsfn);
 329                     return new NodePair(np_src.getBegin(), fsfn);
 330                 } else {
 331                     FlatOpNode fon=new FlatOpNode(getTempforVar(nn.getVar()), src_tmp, null, new Operation(Operation.ASSIGN));
 332                     last.addNext(fon);
 333                     return new NodePair(np_src.getBegin(),fon);
 334                 }
 335             }
 336         }
 337         throw new Error();
 338     }
 339
 340     private NodePair flattenNameNode(NameNode nn,TempDescriptor out_temp) {
 341         if (nn.getExpression()!=null) {
 342             /* Hack - use subtree instead */
 343             return flattenExpressionNode(nn.getExpression(),out_temp);
 344         } else if (nn.getField()!=null) {
 345             TempDescriptor tmp=getTempforVar(nn.getVar());
 346             FlatFieldNode ffn=new FlatFieldNode(nn.getField(), tmp, out_temp);
 347             return new NodePair(ffn,ffn);
 348         } else {
 349             TempDescriptor tmp=getTempforVar(nn.getVar());
 350             FlatOpNode fon=new FlatOpNode(out_temp, tmp, null, new Operation(Operation.ASSIGN));
 351             return new NodePair(fon,fon);
 352         }
 353     }
 354
 355     private NodePair flattenOpNode(OpNode on,TempDescriptor out_temp) {
 356         TempDescriptor temp_left=TempDescriptor.tempFactory("leftop",on.getLeft().getType());
 357         TempDescriptor temp_right=null;
 358
 359         Operation op=on.getOp();
 360         if (op.getOp()==Operation.POSTINC||
 361             op.getOp()==Operation.POSTDEC||
 362             op.getOp()==Operation.PREINC||
 363             op.getOp()==Operation.PREDEC) {
 364             LiteralNode ln=new LiteralNode("int",new Integer(1));
 365             ln.setType(new TypeDescriptor(TypeDescriptor.INT));
 366             AssignmentNode an=new AssignmentNode(on.getLeft(),ln,
 367                                new AssignOperation((op.getOp()==Operation.POSTINC||op.getOp()==Operation.PREINC)?AssignOperation.PLUSEQ:AssignOperation.MINUSEQ));
 368             if (op.getOp()==Operation.POSTINC||
 369                 op.getOp()==Operation.POSTDEC) {
 370                 NodePair left=flattenExpressionNode(on.getLeft(),out_temp);
 371                 NodePair assign=flattenAssignmentNode(an,temp_left);
 372                 left.getEnd().addNext(assign.getBegin());
 373                 return new NodePair(left.getBegin(),assign.getEnd());
 374             } else {
 375                 NodePair assign=flattenAssignmentNode(an,out_temp);
 376                 return assign;
 377             }
 378         }
 379
 380         NodePair left=flattenExpressionNode(on.getLeft(),temp_left);
 381         NodePair right;
 382         if (on.getRight()!=null) {
 383             temp_right=TempDescriptor.tempFactory("rightop",on.getRight().getType());
 384             right=flattenExpressionNode(on.getRight(),temp_right);
 385         } else {
 386             FlatNop nop=new FlatNop();
 387             right=new NodePair(nop,nop);
 388         }
 389
 390         if (op.getOp()==Operation.LOGIC_OR) {
 391             /* Need to do shortcircuiting */
 392             FlatCondBranch fcb=new FlatCondBranch(temp_left);
 393             FlatOpNode fon1=new FlatOpNode(out_temp,temp_left,null,new Operation(Operation.ASSIGN));
 394             FlatOpNode fon2=new FlatOpNode(out_temp,temp_right,null,new Operation(Operation.ASSIGN));
 395             FlatNop fnop=new FlatNop();
 396             left.getEnd().addNext(fcb);
 397             fcb.addFalseNext(right.getBegin());
 398             right.getEnd().addNext(fon2);
 399             fon2.addNext(fnop);
 400             fcb.addTrueNext(fon1);
 401             fon1.addNext(fnop);
 402             return new NodePair(left.getBegin(), fnop);
 403         } else if (op.getOp()==Operation.LOGIC_AND) {
 404             /* Need to do shortcircuiting */
 405             FlatCondBranch fcb=new FlatCondBranch(temp_left);
 406             FlatOpNode fon1=new FlatOpNode(out_temp,temp_left,null,new Operation(Operation.ASSIGN));
 407             FlatOpNode fon2=new FlatOpNode(out_temp,temp_right,null,new Operation(Operation.ASSIGN));
 408             FlatNop fnop=new FlatNop();
 409             left.getEnd().addNext(fcb);
 410             fcb.addTrueNext(right.getBegin());
 411             right.getEnd().addNext(fon2);
 412             fon2.addNext(fnop);
 413             fcb.addFalseNext(fon1);
 414             fon1.addNext(fnop);
 415             return new NodePair(left.getBegin(), fnop);
 416         }
 417
 418         FlatOpNode fon=new FlatOpNode(out_temp,temp_left,temp_right,op);
 419         left.getEnd().addNext(right.getBegin());
 420         right.getEnd().addNext(fon);
 421         return new NodePair(left.getBegin(),fon);
 422     }
 423
 424     private NodePair flattenExpressionNode(ExpressionNode en, TempDescriptor out_temp) {
 425         switch(en.kind()) {
 426         case Kind.AssignmentNode:
 427             return flattenAssignmentNode((AssignmentNode)en,out_temp);
 428         case Kind.CastNode:
 429             return flattenCastNode((CastNode)en,out_temp);
 430         case Kind.CreateObjectNode:
 431             return flattenCreateObjectNode((CreateObjectNode)en,out_temp);
 432         case Kind.FieldAccessNode:
 433             return flattenFieldAccessNode((FieldAccessNode)en,out_temp);
 434         case Kind.ArrayAccessNode:
 435             return flattenArrayAccessNode((ArrayAccessNode)en,out_temp);
 436         case Kind.LiteralNode:
 437             return flattenLiteralNode((LiteralNode)en,out_temp);
 438         case Kind.MethodInvokeNode:
 439             return flattenMethodInvokeNode((MethodInvokeNode)en,out_temp);
 440         case Kind.NameNode:
 441             return flattenNameNode((NameNode)en,out_temp);
 442         case Kind.OpNode:
 443             return flattenOpNode((OpNode)en,out_temp);
 444         }
 445         throw new Error();
 446     }
 447
 448     private NodePair flattenDeclarationNode(DeclarationNode dn) {
 449         VarDescriptor vd=dn.getVarDescriptor();
 450         TempDescriptor td=getTempforVar(vd);
 451         if (dn.getExpression()!=null)
 452             return flattenExpressionNode(dn.getExpression(),td);
 453         else {
 454             FlatNop fn=new FlatNop();
 455             return new NodePair(fn,fn);
 456         }
 457     }
 458
 459     private TempDescriptor getTempforVar(VarDescriptor vd) {
 460         if (temptovar.containsKey(vd))
 461             return (TempDescriptor)temptovar.get(vd);
 462         else {
 463             TempDescriptor td=TempDescriptor.tempFactory(vd.getName(),vd.getType());
 464             temptovar.put(vd,td);
 465             return td;
 466         }
 467     }
 468
 469     private NodePair flattenIfStatementNode(IfStatementNode isn) {
 470         TempDescriptor cond_temp=TempDescriptor.tempFactory("condition",new TypeDescriptor(TypeDescriptor.BOOLEAN));
 471         NodePair cond=flattenExpressionNode(isn.getCondition(),cond_temp);
 472         FlatCondBranch fcb=new FlatCondBranch(cond_temp);
 473         NodePair true_np=flattenBlockNode(isn.getTrueBlock());
 474         NodePair false_np;
 475         FlatNop nopend=new FlatNop();
 476
 477         if (isn.getFalseBlock()!=null)
 478             false_np=flattenBlockNode(isn.getFalseBlock());
 479         else {
 480             FlatNop nop=new FlatNop();
 481             false_np=new NodePair(nop,nop);
 482         }
 483
 484         cond.getEnd().addNext(fcb);
 485         fcb.addTrueNext(true_np.getBegin());
 486         fcb.addFalseNext(false_np.getBegin());
 487         true_np.getEnd().addNext(nopend);
 488         false_np.getEnd().addNext(nopend);
 489         return new NodePair(cond.getBegin(), nopend);
 490     }
 491
 492     private NodePair flattenLoopNode(LoopNode ln) {
 493         if (ln.getType()==LoopNode.FORLOOP) {
 494             NodePair initializer=flattenBlockNode(ln.getInitializer());
 495             TempDescriptor cond_temp=TempDescriptor.tempFactory("condition", new TypeDescriptor(TypeDescriptor.BOOLEAN));
 496             NodePair condition=flattenExpressionNode(ln.getCondition(),cond_temp);
 497             NodePair update=flattenBlockNode(ln.getUpdate());
 498             NodePair body=flattenBlockNode(ln.getBody());
 499             FlatNode begin=initializer.getBegin();
 500             FlatCondBranch fcb=new FlatCondBranch(cond_temp);
 501             FlatNop nopend=new FlatNop();
 502
 503             initializer.getEnd().addNext(condition.getBegin());
 504             body.getEnd().addNext(update.getBegin());
 505             update.getEnd().addNext(condition.getBegin());
 506             condition.getEnd().addNext(fcb);
 507             fcb.addFalseNext(nopend);
 508             fcb.addTrueNext(body.getBegin());
 509             return new NodePair(begin,nopend);
 510         } else if (ln.getType()==LoopNode.WHILELOOP) {
 511             TempDescriptor cond_temp=TempDescriptor.tempFactory("condition", new TypeDescriptor(TypeDescriptor.BOOLEAN));
 512             NodePair condition=flattenExpressionNode(ln.getCondition(),cond_temp);
 513             NodePair body=flattenBlockNode(ln.getBody());
 514             FlatNode begin=condition.getBegin();
 515             FlatCondBranch fcb=new FlatCondBranch(cond_temp);
 516             FlatNop nopend=new FlatNop();
 517
 518             body.getEnd().addNext(condition.getBegin());
 519             condition.getEnd().addNext(fcb);
 520             fcb.addFalseNext(nopend);
 521             fcb.addTrueNext(body.getBegin());
 522             return new NodePair(begin,nopend);
 523         } else if (ln.getType()==LoopNode.DOWHILELOOP) {
 524             TempDescriptor cond_temp=TempDescriptor.tempFactory("condition", new TypeDescriptor(TypeDescriptor.BOOLEAN));
 525             NodePair condition=flattenExpressionNode(ln.getCondition(),cond_temp);
 526             NodePair body=flattenBlockNode(ln.getBody());
 527             FlatNode begin=body.getBegin();
 528             FlatCondBranch fcb=new FlatCondBranch(cond_temp);
 529             FlatNop nopend=new FlatNop();
 530
 531             body.getEnd().addNext(condition.getBegin());
 532             condition.getEnd().addNext(fcb);
 533             fcb.addFalseNext(nopend);
 534             fcb.addTrueNext(body.getBegin());
 535             return new NodePair(begin,nopend);
 536         } else throw new Error();
 537     }
 538
 539     private NodePair flattenReturnNode(ReturnNode rntree) {
 540         TempDescriptor retval=null;
 541         NodePair cond=null;
 542         if (rntree.getReturnExpression()!=null) {
 543             retval=TempDescriptor.tempFactory("ret_value", rntree.getReturnExpression().getType());
 544             cond=flattenExpressionNode(rntree.getReturnExpression(),retval);
 545         }
 546
 547         FlatReturnNode rnflat=new FlatReturnNode(retval);
 548
 549         if (cond!=null) {
 550             cond.getEnd().addNext(rnflat);
 551             return new NodePair(cond.getBegin(),rnflat);
 552         } else
 553             return new NodePair(rnflat,rnflat);
 554     }
 555
 556     private NodePair flattenTaskExitNode(TaskExitNode ten) {
 557         FlatTaskExitNode tenflat=new FlatTaskExitNode();
 558         return new NodePair(tenflat,tenflat);
 559     }
 560
 561     private NodePair flattenSubBlockNode(SubBlockNode sbn) {
 562         return flattenBlockNode(sbn.getBlockNode());
 563     }
 564
 565     private NodePair flattenBlockStatementNode(BlockStatementNode bsn) {
 566         switch(bsn.kind()) {
 567         case Kind.BlockExpressionNode:
 568             return flattenBlockExpressionNode((BlockExpressionNode)bsn);
 569
 570         case Kind.DeclarationNode:
 571             return flattenDeclarationNode((DeclarationNode)bsn);
 572
 573         case Kind.IfStatementNode:
 574             return flattenIfStatementNode((IfStatementNode)bsn);
 575
 576         case Kind.LoopNode:
 577             return flattenLoopNode((LoopNode)bsn);
 578
 579         case Kind.ReturnNode:
 580             return flattenReturnNode((IR.Tree.ReturnNode)bsn);
 581
 582         case Kind.TaskExitNode:
 583             return flattenTaskExitNode((IR.Tree.TaskExitNode)bsn);
 584
 585         case Kind.SubBlockNode:
 586             return flattenSubBlockNode((SubBlockNode)bsn);
 587
 588         }
 589         throw new Error();
 590     }
 591 }