src/org/xwt/js/CompiledFunctionImpl.java

   1 // Copyright 2003 Adam Megacz, see the COPYING file for licensing [GPL]
   2 package org.xwt.js;
   3
   4 import org.xwt.util.*;
   5 import java.io.*;
   6
   7 /** a JavaScript function, compiled into bytecode */
   8 class CompiledFunctionImpl extends JS.Obj implements ByteCodes, Tokens {
   9
  10     // Fields and Accessors ///////////////////////////////////////////////
  11
  12     /** the number of formal arguments */
  13     int numFormalArgs = 20;
  14
  15     /** the source code file that this block was drawn from */
  16      String sourceName;
  17     public String getSourceName() throws JS.Exn { return sourceName; }
  18
  19     /** the line numbers */
  20      int[] line = new int[10];
  21
  22     /** the first line of this script */
  23     private int firstLine = -1;
  24
  25     /** the instructions */
  26      int[] op = new int[10];
  27
  28     /** the arguments to the instructions */
  29      Object[] arg = new Object[10];
  30
  31     /** the number of instruction/argument pairs */
  32      int size = 0;
  33     int size() { return size; }
  34
  35     /** the scope in which this function was declared; by default this function is called in a fresh subscope of the parentScope */
  36     JS.Scope parentScope;
  37
  38     // Constructors ////////////////////////////////////////////////////////
  39
  40     private CompiledFunctionImpl cloneWithNewParentScope(JS.Scope s) throws IOException {
  41         CompiledFunctionImpl ret = new JS.CompiledFunction(sourceName, firstLine, null, s);
  42         // Reuse the same op, arg, line, and size variables for the new "instance" of the function
  43         // NOTE: Neither *this* function nor the new function should be modified after this call
  44         ret.op = this.op;
  45         ret.arg = this.arg;
  46         ret.line = this.line;
  47         ret.size = this.size;
  48         ret.numFormalArgs = this.numFormalArgs;
  49         return ret;
  50     }
  51
  52     protected CompiledFunctionImpl(String sourceName, int firstLine, Reader sourceCode, JS.Scope parentScope) throws IOException {
  53         this.sourceName = sourceName;
  54         this.firstLine = firstLine;
  55         this.parentScope = parentScope;
  56         if (sourceCode == null) return;
  57         Parser p = new Parser(sourceCode, sourceName, firstLine);
  58         while(true) {
  59             int s = size();
  60             p.parseStatement(this, null);
  61             if (s == size()) break;
  62         }
  63         add(-1, LITERAL, null);
  64         add(-1, RETURN);
  65     }
  66
  67
  68
  69     // Adding and Altering Bytecodes ///////////////////////////////////////////////////
  70
  71     int get(int pos) { return op[pos]; }
  72     Object getArg(int pos) { return arg[pos]; }
  73     void set(int pos, int op_, Object arg_) { op[pos] = op_; arg[pos] = arg_; }
  74     void set(int pos, Object arg_) { arg[pos] = arg_; }
  75     int pop() { size--; arg[size] = null; return op[size]; }
  76     void paste(CompiledFunctionImpl other) { for(int i=0; i<other.size; i++) add(other.line[i], other.op[i], other.arg[i]); }
  77     CompiledFunctionImpl add(int line, int op_) { return add(line, op_, null); }
  78     CompiledFunctionImpl add(int line, int op_, Object arg_) {
  79         if (size == op.length - 1) {
  80             int[] line2 = new int[op.length * 2]; System.arraycopy(this.line, 0, line2, 0, op.length); this.line = line2;
  81             Object[] arg2 = new Object[op.length * 2]; System.arraycopy(arg, 0, arg2, 0, arg.length); arg = arg2;
  82             int[] op2 = new int[op.length * 2]; System.arraycopy(op, 0, op2, 0, op.length); op = op2;
  83         }
  84         this.line[size] = line;
  85         op[size] = op_;
  86         arg[size] = arg_;
  87         size++;
  88         return this;
  89     }
  90
  91     public static int getLine(Context cx) {
  92         if(cx.pc < 0 || cx.pc >= ((CompiledFunctionImpl)cx.f).size) return -1;
  93         return ((CompiledFunctionImpl)cx.f).line[cx.pc];
  94     }
  95
  96
  97     // Invoking the Bytecode ///////////////////////////////////////////////////////
  98
  99     /** returns false if the thread has been paused */
 100     static Object eval(final Context cx, Object pushFirst) throws JS.Exn {
 101         cx.stack.push(pushFirst);
 102         OUTER: for(;; cx.pc++) {
 103         try {
 104             if (cx.f == null) return cx.stack.pop();
 105             if (cx.pc >= ((CompiledFunctionImpl)cx.f).size) return cx.stack.pop();
 106             String label = null;
 107             int curOP = cx.f.op[cx.pc];
 108             Object curArg = cx.f.arg[cx.pc];
 109             Object returnedFromJava = null;
 110             boolean checkReturnedFromJava = false;
 111             if(curOP == FINALLY_DONE) {
 112                 FinallyData fd = (FinallyData) cx.stack.pop();
 113                 if(fd == null) continue OUTER; // NOP
 114                 curOP = fd.op;
 115                 curArg = fd.arg;
 116             }
 117             switch(curOP) {
 118             case LITERAL: cx.stack.push(curArg); break;
 119             case OBJECT: cx.stack.push(new JS.Obj()); break;
 120             case ARRAY: cx.stack.push(new JS.Array(JS.toNumber(curArg).intValue())); break;
 121             case DECLARE: cx.scope.declare((String)(curArg==null ? cx.stack.peek() : curArg)); if(curArg != null) cx.stack.push(curArg); break;
 122             case TOPSCOPE: cx.stack.push(cx.scope); break;
 123             case JT: if (JS.toBoolean(cx.stack.pop())) cx.pc += JS.toNumber(curArg).intValue() - 1; break;
 124             case JF: if (!JS.toBoolean(cx.stack.pop())) cx.pc += JS.toNumber(curArg).intValue() - 1; break;
 125             case JMP: cx.pc += JS.toNumber(curArg).intValue() - 1; break;
 126             case POP: cx.stack.pop(); break;
 127             case SWAP: { Object o1 = cx.stack.pop(); Object o2 = cx.stack.pop(); cx.stack.push(o1); cx.stack.push(o2); break; }
 128             case DUP: cx.stack.push(cx.stack.peek()); break;
 129             case NEWSCOPE: cx.scope = new JS.Scope(cx.scope); break;
 130             case OLDSCOPE: cx.scope = cx.scope.getParentScope(); break;
 131             case ASSERT: if (!JS.toBoolean(cx.stack.pop())) throw je("assertion failed"); break;
 132             case BITNOT: cx.stack.push(new Long(~JS.toLong(cx.stack.pop()))); break;
 133             case BANG: cx.stack.push(new Boolean(!JS.toBoolean(cx.stack.pop()))); break;
 134
 135             case TYPEOF: {
 136                 Object o = cx.stack.pop();
 137                 if (o == null) cx.stack.push(null);
 138                 else if (o instanceof JS) cx.stack.push(((JS)o).typeName());
 139                 else if (o instanceof String) cx.stack.push("string");
 140                 else if (o instanceof Number) cx.stack.push("number");
 141                 else if (o instanceof Boolean) cx.stack.push("boolean");
 142                 else cx.stack.push("unknown");
 143                 break;
 144             }
 145
 146             case NEWFUNCTION: {
 147                 try {
 148                     cx.stack.push(((CompiledFunctionImpl)curArg).cloneWithNewParentScope(cx.scope));
 149                 } catch (IOException e) {
 150                     throw new Error("this should never happen");
 151                 }
 152                 break;
 153             }
 154
 155             case PUSHKEYS: {
 156                 Object o = cx.stack.peek();
 157                 Object[] keys = ((JS)o).keys();
 158                 JS.Array a = new JS.Array();
 159                 a.setSize(keys.length);
 160                 for(int j=0; j<keys.length; j++) a.setElementAt(keys[j], j);
 161                 cx.stack.push(a);
 162                 break;
 163             }
 164
 165             case LABEL: break;
 166             case LOOP: {
 167                 cx.stack.push(new LoopMarker(cx.pc, cx.pc > 0 && cx.f.op[cx.pc - 1] == LABEL ? (String)cx.f.arg[cx.pc - 1] : (String)null, cx.scope));
 168                 cx.stack.push(Boolean.TRUE);
 169                 break;
 170             }
 171
 172             case BREAK:
 173             case CONTINUE:
 174                 while(cx.stack.size() > 0) {
 175                     Object o = cx.stack.pop();
 176                     if (o instanceof CallMarker) ee("break or continue not within a loop");
 177                     if (o instanceof TryMarker) {
 178                         if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
 179                         cx.stack.push(new FinallyData(curOP, curArg));
 180                         cx.scope = ((TryMarker)o).scope;
 181                         cx.pc = ((TryMarker)o).finallyLoc - 1;
 182                         continue OUTER;
 183                     }
 184                     if (o instanceof LoopMarker) {
 185                         if (curArg == null || curArg.equals(((LoopMarker)o).label)) {
 186                             int loopInstructionLocation = ((LoopMarker)o).location;
 187                             int endOfLoop = ((Integer)cx.f.arg[loopInstructionLocation]).intValue() + loopInstructionLocation;
 188                             cx.scope = ((LoopMarker)o).scope;
 189                             if (curOP == CONTINUE) { cx.stack.push(o); cx.stack.push(Boolean.FALSE); }
 190                             cx.pc = curOP == BREAK ? endOfLoop - 1 : loopInstructionLocation;
 191                             continue OUTER;
 192                         }
 193                     }
 194                 }
 195                 throw new Error("CONTINUE/BREAK invoked but couldn't find a LoopMarker at " + ((CompiledFunctionImpl)cx.f).sourceName + ":" + getLine(cx));
 196
 197             case TRY: {
 198                 int[] jmps = (int[]) curArg;
 199                 // jmps[0] is how far away the catch block is, jmps[1] is how far away the finally block is
 200                 // each can be < 0 if the specified block does not exist
 201                 cx.stack.push(new TryMarker(jmps[0] < 0 ? -1 : cx.pc + jmps[0], jmps[1] < 0 ? -1 : cx.pc + jmps[1], cx.scope));
 202                 break;
 203             }
 204
 205             case RETURN: {
 206                 Object retval = cx.stack.pop();
 207                 while(cx.stack.size() > 0) {
 208                     Object o = cx.stack.pop();
 209                     if (o instanceof TryMarker) {
 210                         if(((TryMarker)o).finallyLoc < 0) continue;
 211                         cx.stack.push(retval);
 212                         cx.stack.push(new FinallyData(RETURN));
 213                         cx.scope = ((TryMarker)o).scope;
 214                         cx.pc = ((TryMarker)o).finallyLoc - 1;
 215                         continue OUTER;
 216                     }
 217                     if (o instanceof CallMarker) {
 218                         cx.scope = ((CallMarker)o).scope;
 219                         cx.pc = ((CallMarker)o).pc;
 220                         cx.f = (CompiledFunction)((CallMarker)o).f;
 221                         cx.stack.push(retval);
 222                         continue OUTER;
 223                     }
 224                 }
 225                 throw new Error("error: RETURN invoked but couldn't find a CallMarker!");
 226             }
 227
 228             case PUT: {
 229                 Object val = cx.stack.pop();
 230                 Object key = cx.stack.pop();
 231                 Object target = cx.stack.peek();
 232                 if (target == null)
 233                     throw je("tried to put a value to the " + key + " property on the null value");
 234                 if (!(target instanceof JS))
 235                     throw je("tried to put a value to the " + key + " property on a " + target.getClass().getName());
 236                 if (key == null)
 237                     throw je("tried to assign \"" + (val==null?"(null)":val.toString()) + "\" to the null key");
 238                 returnedFromJava = ((JS)target).put(key, val);
 239                 if (returnedFromJava != null) {
 240                     checkReturnedFromJava = true;
 241                 } else {
 242                     cx.stack.push(val);
 243                 }
 244                 break;
 245             }
 246
 247             case GET:
 248             case GET_PRESERVE: {
 249                 Object o, v;
 250                 if (curOP == GET) {
 251                     v = curArg == null ? cx.stack.pop() : curArg;
 252                     o = cx.stack.pop();
 253                 } else {
 254                     v = cx.stack.pop();
 255                     o = cx.stack.peek();
 256                     cx.stack.push(v);
 257                 }
 258                 Object ret = null;
 259                 if (o == null) throw je("tried to get property \"" + v + "\" from the null value");
 260                 if (v == null) throw je("tried to get the null key from " + o);
 261                 if (o instanceof String || o instanceof Number || o instanceof Boolean)
 262                     ret = Internal.getFromPrimitive(o,v);
 263                 else if (o instanceof JS) {
 264                     returnedFromJava = ((JS)o).get(v);
 265                     checkReturnedFromJava = true;
 266                     break;
 267                 } else
 268                     throw je("tried to get property " + v + " from a " + o.getClass().getName());
 269                 cx.stack.push(ret);
 270                 break;
 271             }
 272
 273             case CALLMETHOD:
 274             case CALL:
 275             case CALL_REVERSED:
 276             {
 277                 JS.Array arguments = new JS.Array();
 278                 int numArgs = JS.toNumber(curArg).intValue();
 279                 arguments.setSize(numArgs);
 280                 Object o = null;
 281                 if (curOP == CALL_REVERSED) o = cx.stack.pop();
 282                 for(int j=numArgs - 1; j >= 0; j--) arguments.setElementAt(cx.stack.pop(), j);
 283                 if (curOP != CALL_REVERSED) o = cx.stack.pop();
 284                 if(o == null) throw je("attempted to call null");
 285                 Object ret;
 286
 287                 if(curOP == CALLMETHOD) {
 288                     Object method = o;
 289                     o = cx.stack.pop();
 290                     if(o instanceof String || o instanceof Number || o instanceof Boolean) {
 291                         ret = Internal.callMethodOnPrimitive(o,method,arguments);
 292                         cx.stack.push(ret);
 293                         cx.pc += 2;  // skip the GET and CALL
 294                         break;
 295                     } else if (o instanceof JS && ((JS)o).callMethod(method, arguments, true) == Boolean.TRUE) {
 296                         returnedFromJava = ((JS)o).callMethod(method, arguments, false);
 297                         checkReturnedFromJava = true;
 298                         cx.pc += 2;  // skip the GET and CALL
 299                         break;
 300                     } else {
 301                         // put the args back on the stack and let the GET followed by CALL happen
 302                         for(int j=0; j<numArgs; j++) cx.stack.push(arguments.elementAt(j));
 303                         cx.stack.push(o);
 304                         cx.stack.push(method);
 305                         break;
 306                     }
 307                 }
 308
 309                 if (o instanceof CompiledFunctionImpl) {
 310                     cx.stack.push(new CallMarker(cx));
 311                     cx.stack.push(arguments);
 312                     cx.f = (CompiledFunction)o;
 313                     cx.scope = new FunctionScope("unknown", cx.f.parentScope);
 314                     cx.pc = -1;
 315                     break;
 316
 317                 } else {
 318                     returnedFromJava = ((JS.Callable)o).call(arguments);
 319                     checkReturnedFromJava = true;
 320                     break;
 321                 }
 322             }
 323
 324             case THROW: {
 325                 Object o = cx.stack.pop();
 326                 if(o instanceof JS.Exn) throw (JS.Exn)o;
 327                 throw new JS.Exn(o);
 328             }
 329
 330             case INC: case DEC: {
 331                 boolean isPrefix = JS.toBoolean(curArg);
 332                 Object key = cx.stack.pop();
 333                 JS obj = (JS)cx.stack.pop();
 334                 Number num = JS.toNumber(obj.get(key));
 335                 Number val = new Double(curOP == INC ? num.doubleValue() + 1.0 : num.doubleValue() - 1.0);
 336                 obj.put(key, val);
 337                 cx.stack.push(isPrefix ? val : num);
 338                 break;
 339             }
 340
 341             case ASSIGN_SUB: case ASSIGN_ADD: {
 342                 Object val = cx.stack.pop();
 343                 Object old = cx.stack.pop();
 344                 Object key = cx.stack.pop();
 345                 Object obj = cx.stack.peek();
 346                 if (val instanceof CompiledFunction) {
 347                     if (obj instanceof JS.Scope) {
 348                         JS.Scope parent = (JS.Scope)obj;
 349                         while(parent.getParentScope() != null) parent = parent.getParentScope();
 350                         if (parent instanceof org.xwt.Box) {
 351                             if (curOP == ASSIGN_ADD) {
 352                                 ((org.xwt.Box)parent).addTrap(key, val);
 353                             } else {
 354                                 ((org.xwt.Box)parent).delTrap(key, val);
 355                             }
 356                             // skip over the "normal" implementation of +=/-=
 357                             cx.pc += ((Integer)curArg).intValue() - 1;
 358                             break;
 359                         }
 360                     }
 361                 }
 362                 // use the "normal" implementation
 363                 cx.stack.push(key);
 364                 cx.stack.push(old);
 365                 cx.stack.push(val);
 366                 break;
 367             }
 368
 369             case ADD: {
 370                 int count = ((Number)curArg).intValue();
 371                 if(count < 2) throw new Error("this should never happen");
 372                 if(count == 2) {
 373                     // common case
 374                     Object right = cx.stack.pop();
 375                     Object left = cx.stack.pop();
 376                     if(left instanceof String || right instanceof String) cx.stack.push(JS.toString(left).concat(JS.toString(right)));
 377                     else cx.stack.push(new Double(JS.toDouble(left) + JS.toDouble(right)));
 378                 } else {
 379                     Object[] args = new Object[count];
 380                     while(--count >= 0) args[count] = cx.stack.pop();
 381                     if(args[0] instanceof String) {
 382                         StringBuffer sb = new StringBuffer(64);
 383                         for(int i=0;i<args.length;i++) sb.append(JS.toString(args[i]));
 384                         cx.stack.push(sb.toString());
 385                     } else {
 386                         int numStrings = 0;
 387                         for(int i=0;i<args.length;i++) if(args[i] instanceof String) numStrings++;
 388                         if(numStrings == 0) {
 389                             double d = 0.0;
 390                             for(int i=0;i<args.length;i++) d += JS.toDouble(args[i]);
 391                             cx.stack.push(new Double(d));
 392                         } else {
 393                             int i=0;
 394                             StringBuffer sb = new StringBuffer(64);
 395                             if(!(args[0] instanceof String || args[1] instanceof String)) {
 396                                 double d=0.0;
 397                                 do {
 398                                     d += JS.toDouble(args[i++]);
 399                                 } while(!(args[i] instanceof String));
 400                                 sb.append(JS.toString(new Double(d)));
 401                             }
 402                             while(i < args.length) sb.append(JS.toString(args[i++]));
 403                             cx.stack.push(sb.toString());
 404                         }
 405                     }
 406                 }
 407                 break;
 408             }
 409
 410             default: {
 411                 Object right = cx.stack.pop();
 412                 Object left = cx.stack.pop();
 413                 switch(curOP) {
 414
 415                 case BITOR: cx.stack.push(new Long(JS.toLong(left) | JS.toLong(right))); break;
 416                 case BITXOR: cx.stack.push(new Long(JS.toLong(left) ^ JS.toLong(right))); break;
 417                 case BITAND: cx.stack.push(new Long(JS.toLong(left) & JS.toLong(right))); break;
 418
 419                 case SUB: cx.stack.push(new Double(JS.toDouble(left) - JS.toDouble(right))); break;
 420                 case MUL: cx.stack.push(new Double(JS.toDouble(left) * JS.toDouble(right))); break;
 421                 case DIV: cx.stack.push(new Double(JS.toDouble(left) / JS.toDouble(right))); break;
 422                 case MOD: cx.stack.push(new Double(JS.toDouble(left) % JS.toDouble(right))); break;
 423
 424                 case LSH: cx.stack.push(new Long(JS.toLong(left) << JS.toLong(right))); break;
 425                 case RSH: cx.stack.push(new Long(JS.toLong(left) >> JS.toLong(right))); break;
 426                 case URSH: cx.stack.push(new Long(JS.toLong(left) >>> JS.toLong(right))); break;
 427
 428                 case LT: case LE: case GT: case GE: {
 429                     if (left == null) left = new Integer(0);
 430                     if (right == null) right = new Integer(0);
 431                     int result = 0;
 432                     if (left instanceof String || right instanceof String) {
 433                         result = left.toString().compareTo(right.toString());
 434                     } else {
 435                         result = (int)java.lang.Math.ceil(JS.toDouble(left) - JS.toDouble(right));
 436                     }
 437                     cx.stack.push(new Boolean((curOP == LT && result < 0) || (curOP == LE && result <= 0) ||
 438                                        (curOP == GT && result > 0) || (curOP == GE && result >= 0)));
 439                     break;
 440                 }
 441
 442                 case EQ:
 443                 case NE: {
 444                     Object l = left;
 445                     Object r = right;
 446                     boolean ret;
 447                     if (l == null) { Object tmp = r; r = l; l = tmp; }
 448                     if (l == null && r == null) ret = true;
 449                     else if (r == null) ret = false; // l != null, so its false
 450                     else if (l instanceof Boolean) ret = new Boolean(JS.toBoolean(r)).equals(l);
 451                     else if (l instanceof Number) ret = JS.toNumber(r).doubleValue() == JS.toNumber(l).doubleValue();
 452                     else if (l instanceof String) ret = r != null && l.equals(r.toString());
 453                     else ret = l.equals(r);
 454                     cx.stack.push(new Boolean(curOP == EQ ? ret : !ret)); break;
 455                 }
 456
 457                 default: throw new Error("unknown opcode " + curOP);
 458                 } }
 459             }
 460
 461             // handle special directions returned from Java callouts
 462             // ideally we would do this with exceptions, but they're *very* slow in gcj
 463             if (checkReturnedFromJava) {
 464                 checkReturnedFromJava = false;
 465                 if (returnedFromJava == Context.pause) {
 466                     cx.pc++;
 467                     return Context.pause;
 468                 } else if (returnedFromJava instanceof TailCall) {
 469                     cx.stack.push(new CallMarker(cx));
 470                     cx.stack.push(((JS.TailCall)returnedFromJava).args);
 471                     cx.f = ((JS.TailCall)returnedFromJava).func;
 472                     cx.scope = new CompiledFunctionImpl.FunctionScope("unknown", cx.f.parentScope);
 473                     cx.pc = -1;
 474                 } else {
 475                     cx.stack.push(returnedFromJava);
 476                 }
 477                 continue OUTER;
 478             }
 479
 480
 481         } catch(JS.Exn e) {
 482             while(cx.stack.size() > 0) {
 483                 Object o = cx.stack.pop();
 484                 if (o instanceof CatchMarker || o instanceof TryMarker) {
 485                     boolean inCatch = o instanceof CatchMarker;
 486                     if(inCatch) {
 487                         o = cx.stack.pop();
 488                         if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
 489                     }
 490                     if(!inCatch && ((TryMarker)o).catchLoc >= 0) {
 491                         // run the catch block, this will implicitly run the finally block, if it exists
 492                         cx.stack.push(o);
 493                         cx.stack.push(catchMarker);
 494                         cx.stack.push(e.getObject());
 495                         cx.scope = ((TryMarker)o).scope;
 496                         cx.pc = ((TryMarker)o).catchLoc - 1;
 497                         continue OUTER;
 498                     } else {
 499                         cx.stack.push(e);
 500                         cx.stack.push(new FinallyData(THROW));
 501                         cx.scope = ((TryMarker)o).scope;
 502                         cx.pc = ((TryMarker)o).finallyLoc - 1;
 503                         continue OUTER;
 504                     }
 505                 }
 506                 // no handler found within this func
 507                 if(o instanceof CallMarker) throw e;
 508             }
 509             throw e;
 510         } // end try/catch
 511         } // end for
 512     }
 513
 514     // Debugging //////////////////////////////////////////////////////////////////////
 515
 516     public String toString() {
 517         StringBuffer sb = new StringBuffer(1024);
 518         sb.append("\n" + sourceName + ": " + firstLine + "\n");
 519         for (int i=0; i < size; i++) {
 520             sb.append(i);
 521             sb.append(": ");
 522             if (op[i] < 0)
 523                 sb.append(bytecodeToString[-op[i]]);
 524             else
 525                 sb.append(codeToString[op[i]]);
 526             sb.append(" ");
 527             sb.append(arg[i] == null ? "(no arg)" : arg[i]);
 528             if((op[i] == JF || op[i] == JT || op[i] == JMP) && arg[i] != null && arg[i] instanceof Number) {
 529                 sb.append(" jump to ").append(i+((Number) arg[i]).intValue());
 530             } else  if(op[i] == TRY) {
 531                 int[] jmps = (int[]) arg[i];
 532                 sb.append(" catch: ").append(jmps[0] < 0 ? "No catch block" : ""+(i+jmps[0]));
 533                 sb.append(" finally: ").append(jmps[1] < 0 ? "No finally block" : ""+(i+jmps[1]));
 534             }
 535             sb.append("\n");
 536         }
 537         return sb.toString();
 538     }
 539
 540     // Exception Stuff ////////////////////////////////////////////////////////////////
 541
 542     static class EvaluatorException extends RuntimeException { public EvaluatorException(String s) { super(s); } }
 543     static EvaluatorException ee(String s) {
 544         throw new EvaluatorException(JS.Context.getSourceName() + ":" + JS.Context.getLine() + " " + s);
 545     }
 546     static JS.Exn je(String s) {
 547         throw new JS.Exn(JS.Context.getSourceName() + ":" + JS.Context.getLine() + " " + s);
 548     }
 549
 550     // FunctionScope /////////////////////////////////////////////////////////////////
 551
 552     static class FunctionScope extends JS.Scope {
 553         String sourceName;
 554         public FunctionScope(String sourceName, Scope parentScope) { super(parentScope); this.sourceName = sourceName; }
 555         public String getSourceName() { return sourceName; }
 556     }
 557
 558
 559     // Markers //////////////////////////////////////////////////////////////////////
 560
 561     public static class CallMarker {
 562         int pc;
 563         Scope scope;
 564         CompiledFunctionImpl f;
 565         public CallMarker(Context cx) { pc = cx.pc + 1; scope = cx.scope; f = cx.f; }
 566     }
 567
 568     public static class CatchMarker { public CatchMarker() { } }
 569     private static CatchMarker catchMarker = new CatchMarker();
 570
 571     public static class LoopMarker {
 572         public int location;
 573         public String label;
 574         public JS.Scope scope;
 575         public LoopMarker(int location, String label, JS.Scope scope) {
 576             this.location = location;
 577             this.label = label;
 578             this.scope = scope;
 579         }
 580     }
 581     public static class TryMarker {
 582         public int catchLoc;
 583         public int finallyLoc;
 584         public JS.Scope scope;
 585         public TryMarker(int catchLoc, int finallyLoc, JS.Scope scope) {
 586             this.catchLoc = catchLoc;
 587             this.finallyLoc = finallyLoc;
 588             this.scope = scope;
 589         }
 590     }
 591     public static class FinallyData {
 592         public int op;
 593         public Object arg;
 594         public FinallyData(int op, Object arg) { this.op = op; this.arg = arg; }
 595         public FinallyData(int op) { this(op,null); }
 596     }
 597 }
 598
 599 /** this class exists solely to work around a GCJ bug */
 600 abstract class JSCallable extends JS.Callable {
 601         public abstract Object call(JS.Array args) throws JS.Exn;
 602 }