1 // Copyright 2000-2005 the Contributors, as shown in the revision logs.
2 // Licensed under the Apache Public Source License 2.0 ("the License").
3 // You may not use this file except in compliance with the License.
7 import org.ibex.util.*;
10 /** Encapsulates a single JS interpreter (ie call stack) */
11 class Interpreter implements ByteCodes, Tokens, Pausable {
12 // Thread-Interpreter Mapping /////////////////////////////////////////////////////////////////////////
14 static Interpreter current() { return (Interpreter)threadToInterpreter.get(Thread.currentThread()); }
15 private static Hashtable threadToInterpreter = new Hashtable();
18 // Instance members and methods //////////////////////////////////////////////////////////////////////
20 int pausecount; ///< the number of times pause() has been invoked; -1 indicates unpauseable
21 JSFunction f = null; ///< the currently-executing JSFunction
22 JSScope scope; ///< the current top-level scope (LIFO stack via NEWSCOPE/OLDSCOPE)
23 final Stack stack = new Stack(); ///< the object stack
24 int pc = 0; ///< the program counter
26 Interpreter(JSFunction f, boolean pauseable, JS[] args) {
28 this.pausecount = pauseable ? 0 : -1;
29 this.scope = f.parentScope;
31 stack.push(new CallMarker(null)); // the "root function returned" marker -- f==null
34 throw new Error("should never happen");
38 Interpreter(JS.Trap t, JS val, boolean pauseOnPut) {
41 setupTrap(t,val,new TrapMarker(null,t,val,pauseOnPut));
43 throw new Error("should never happen");
47 private boolean get = false;
48 // FIXME: split this stuff out into a Script instance control object
49 // so it's possible to make JS either single or multi threaded.
50 /** this is the only synchronization point we need in order to be threadsafe */
51 public synchronized Object run(Object o) throws JSExn {
52 if (f == null) throw new AlreadyRunningException("function already finished");
53 if (scope == null) throw new RuntimeException("scope is null");
55 Thread t = Thread.currentThread();
56 Interpreter old = (Interpreter)threadToInterpreter.get(t);
57 threadToInterpreter.put(t, this);
59 if (get) stack.push(o);
64 if (old == null) threadToInterpreter.remove(t);
65 else threadToInterpreter.put(t, old);
69 public void pause() throws NotPausableException {
70 if (pausecount == -1 || f == null) throw new NotPausableException();
73 case Tokens.RETURN: case ByteCodes.PUT: get = false; break;
74 case ByteCodes.GET: case ByteCodes.CALL: get = true; break;
75 default: throw new Error("should never happen");
79 static int getLine() {
80 Interpreter c = Interpreter.current();
81 return c == null || c.f == null || c.pc < 0 || c.pc >= c.f.size ? -1 : c.f.line[c.pc];
84 static String getSourceName() {
85 Interpreter c = Interpreter.current();
86 return c == null || c.f == null ? null : c.f.sourceName;
89 private static JSExn je(String s) { return new JSExn(getSourceName() + ":" + getLine() + " " + s); }
91 private JS run() throws JSExn {
93 // if pausecount changes after a get/put/call, we know we've been paused
94 final int initialPauseCount = pausecount;
99 Object arg = f.arg[pc];
100 if(op == FINALLY_DONE) {
101 FinallyData fd = (FinallyData) stack.pop();
102 if(fd == null) continue OUTER; // NOP
103 if(fd.exn != null) throw fd.exn;
108 case LITERAL: stack.push((JS)arg); break;
109 case OBJECT: stack.push(new JS.Obj()); break;
110 case ARRAY: stack.push(new JSArray(Script.toInt((JS)arg))); break;
111 //case DECLARE: scope.declare((JS)(arg==null ? stack.peek() : arg)); if(arg != null) stack.push((JS)arg); break;
112 case JT: if (Script.toBoolean(stack.pop())) pc += Script.toInt((JS)arg) - 1; break;
113 case JF: if (!Script.toBoolean(stack.pop())) pc += Script.toInt((JS)arg) - 1; break;
114 case JMP: pc += Script.toInt((JS)arg) - 1; break;
115 case POP: stack.pop(); break;
116 case SWAP: stack.swap(); break;
117 case DUP: stack.push(stack.peek()); break;
119 int n = Script.toInt((JS)arg);
120 scope = new JSScope(scope,(n>>>16)&0xffff,(n>>>0)&0xffff);
123 case OLDSCOPE: scope = scope.parent; break;
124 case GLOBALSCOPE: stack.push(scope.getGlobal()); break;
125 case SCOPEGET: stack.push(scope.get((JS)arg)); break;
126 case SCOPEPUT: scope.put((JS)arg,stack.peek()); break;
127 case ASSERT: if (!Script.toBoolean(stack.pop())) throw je("ibex.assertion.failed"); break;
128 case BITNOT: stack.push(Script.N(~Script.toLong(stack.pop()))); break;
129 case BANG: stack.push(Script.B(!Script.toBoolean(stack.pop()))); break;
130 case NEWFUNCTION: stack.push(((JSFunction)arg)._cloneWithNewParentScope(scope)); break;
134 Object o = stack.pop();
135 if (o == null) stack.push(null);
136 else if (o instanceof JSString) stack.push(Script.S("string"));
137 else if (o instanceof JSNumber.B) stack.push(Script.S("boolean"));
138 else if (o instanceof JSNumber) stack.push(Script.S("number"));
139 else stack.push(Script.S("object"));
144 JS o = (JS)stack.peek();
145 stack.push(o == null ? null : o.keys());
150 stack.push(new LoopMarker(pc, (String)(pc > 0 && f.op[pc - 1] == LABEL ? f.arg[pc - 1] : null), scope));
151 stack.push(Script.T);
156 while(!stack.empty()) {
157 JS o = (JS)stack.pop();
158 if (o instanceof CallMarker) je("break or continue not within a loop");
159 if (o instanceof TryMarker) {
160 if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
161 stack.push(new FinallyData(op, arg));
162 scope = ((TryMarker)o).scope;
163 pc = ((TryMarker)o).finallyLoc - 1;
166 if (o instanceof LoopMarker) {
167 if (arg == null || arg.equals(((LoopMarker)o).label)) {
168 int loopInstructionLocation = ((LoopMarker)o).location;
169 int endOfLoop = Script.toInt((JS)f.arg[loopInstructionLocation]) + loopInstructionLocation;
170 scope = ((LoopMarker)o).scope;
171 if (op == CONTINUE) { stack.push(o); stack.push(JS.F); }
172 pc = op == BREAK ? endOfLoop - 1 : loopInstructionLocation;
177 throw new Error("CONTINUE/BREAK invoked but couldn't find LoopMarker at " +
178 getSourceName() + ":" + getLine());
181 int[] jmps = (int[]) arg;
182 // jmps[0] is how far away the catch block is, jmps[1] is how far away the finally block is
183 // each can be < 0 if the specified block does not exist
184 stack.push(new TryMarker(jmps[0] < 0 ? -1 : pc + jmps[0], jmps[1] < 0 ? -1 : pc + jmps[1], this));
189 JS retval = (JS)stack.pop();
190 while(!stack.empty()) {
191 Object o = stack.pop();
192 if (o instanceof TryMarker) {
193 if(((TryMarker)o).finallyLoc < 0) continue;
195 stack.push(new FinallyData(RETURN));
196 scope = ((TryMarker)o).scope;
197 pc = ((TryMarker)o).finallyLoc - 1;
199 } else if (o instanceof CallMarker) {
200 boolean didTrapPut = false;
201 if (o instanceof TrapMarker) { // handles return component of a write trap
202 TrapMarker tm = (TrapMarker) o;
203 boolean cascade = tm.t.isWriteTrap() && !tm.cascadeHappened && !Script.toBoolean(retval);
205 JS.Trap t = tm.t.nextWrite();
206 if(t == null && tm.t.target() instanceof JS.Clone) {
207 t = ((JS.Clone)tm.t.target()).clonee.getTrap(tm.t.key());
208 if(t != null && !t.isWriteTrap()) t = t.nextWrite();
211 tm.t = t; // we reuse the old trap marker
212 setupTrap(t, tm.val, tm);
213 pc--; // we increment it on the next iter
217 if(!tm.pauseOnPut) tm.t.target().put(tm.t.key(), tm.val);
221 CallMarker cm = (CallMarker) o;
226 if (((TrapMarker)cm).pauseOnPut) { pc++; return ((TrapMarker)cm).val; }
227 if (pausecount > initialPauseCount) { pc++; return null; } // we were paused
231 if (f == null) return retval;
235 throw new Error("error: RETURN invoked but couldn't find a CallMarker!");
239 boolean write = Script.toBoolean((JS)arg);
240 JS val = write ? stack.pop() : null;
241 CallMarker o = stack.findCall();
242 if(!(o instanceof TrapMarker)) throw new JSExn("tried to CASCADE while not in a trap");
243 TrapMarker tm = (TrapMarker) o;
245 JS target = tm.t.target();
246 if(tm.t.isWriteTrap() != write) throw new JSExn("tried to do a " + (write?"write":"read") + " cascade in a " + (write?"read":"write") + " trap");
247 JS.Trap t = write ? tm.t.nextWrite() : tm.t.nextRead();
248 // FIXME: Doesn't handle multiple levels of clone's (probably can just make this a while loop)
249 if(t == null && target instanceof JS.Clone) {
250 target = ((JS.Clone)target).clonee;
251 t = target.getTrap(key);
252 if(t != null) t = write ? t.write() : t.read();
255 tm.cascadeHappened = true;
259 setupTrap(t,val,new TrapMarker(this,t,val,tm.pauseOnPut));
260 pc--; // we increment later
263 if (tm.pauseOnPut) { pc++; return val; }
266 JS ret = target.get(key);
267 if (ret != null && ret instanceof JS.Method) ret = new Stub(target, key);
270 if (pausecount > initialPauseCount) { pc++; return null; } // we were paused
276 JS val = (JS)stack.pop();
277 JS key = (JS)stack.pop();
278 JS target = (JS)stack.peek();
279 if (target == null) throw je("tried to put " + Script.str(val) + " to the " + Script.str(key) + " property on the null value");
280 if (key == null) throw je("tried to assign \"" + Script.str(val) + "\" to the null key");
282 JS.Trap t = target.getTrap(key);
283 if(t != null) t = t.write();
285 if(t == null && target instanceof JS.Clone) {
286 target = ((JS.Clone)target).clonee;
287 t = target.getTrap(key);
288 if(t != null) t = t.nextWrite();
294 setupTrap(t,val,new TrapMarker(this,t,val));
295 pc--; // we increment later
298 if (pausecount > initialPauseCount) { pc++; return null; } // we were paused
307 key = arg == null ? (JS)stack.pop() : (JS)arg;
308 target = (JS)stack.pop();
310 key = (JS)stack.pop();
311 target = (JS)stack.peek();
315 if (key == null) throw je("tried to get the null key from " + Script.str(target));
316 if (target == null) throw je("tried to get property \"" + Script.str(key) + "\" from the null object");
318 JS.Trap t = target.getTrap(key);
319 if(t != null) t = t.read();
321 if(t == null && target instanceof JS.Clone) {
322 target = ((JS.Clone)target).clonee;
323 t = target.getTrap(key);
324 if(t != null) t = t.nextRead();
328 setupTrap(t,null,new TrapMarker(this,t,null));
329 pc--; // we increment later
331 ret = target.get(key);
332 if (pausecount > initialPauseCount) { pc++; return null; } // we were paused
334 if (ret != null && ret instanceof JS.Method) ret = new Stub(target, key);
340 case CALL: case CALLMETHOD: {
341 JS[] jsargs = (JS[])arg;
345 JS object = (JS)stack.pop();
347 if (op == CALLMETHOD) {
348 if (object == null) {
349 method = (JS)stack.pop();
350 object = (JS)stack.pop();
351 throw new JSExn("function '"+Script.str(method)+"' not found in " + object.getClass().getName());
352 } else if (object instanceof JS.Method) {
353 method = (JS)stack.pop();
354 object = (JS)stack.pop();
361 if (object instanceof JSFunction) {
362 stack.push(new CallMarker(this));
364 f = (JSFunction)object;
365 scope = f.parentScope;
370 ret = method == null ? c.call(jsargs) : c.call(method, jsargs);
373 if (pausecount > initialPauseCount) { pc++; return null; }
379 throw new JSExn((JS)stack.pop(), this);
383 final Grammar r = (Grammar)arg;
384 final JSScope final_scope = scope;
385 Grammar r2 = new Grammar() {
386 public int match(String s, int start, Map v, JSScope scope) throws JSExn {
387 return r.match(s, start, v, final_scope);
389 public int matchAndWrite(String s, int start, Map v, JSScope scope, String key) throws JSExn {
390 return r.matchAndWrite(s, start, v, final_scope, key);
392 public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
394 r.matchAndWrite((String)a0, 0, v, final_scope, "foo");
398 Object obj = stack.pop();
399 if (obj != null && obj instanceof Grammar) r2 = new Grammar.Alternative((Grammar)obj, r2);
404 case ADD_TRAP: case DEL_TRAP: {
405 JS val = (JS)stack.pop();
406 JS key = (JS)stack.pop();
407 JS js = (JS)stack.peek();
408 // A trap addition/removal
409 if(!(val instanceof JSFunction)) throw new JSExn("tried to add/remove a non-function trap");
410 if(op == ADD_TRAP) js.addTrap(key, val);
411 else js.delTrap(key, val);
416 int count = ((JSNumber)arg).toInt();
417 if(count < 2) throw new Error("this should never happen");
420 JS right = (JS)stack.pop();
421 JS left = (JS)stack.pop();
423 if(left instanceof JSString || right instanceof JSString)
424 ret = Script.S(Script.toString(left).concat(Script.toString(right)));
425 else if(left instanceof JSNumber.D || right instanceof JSNumber.D)
426 ret = Script.N(Script.toDouble(left) + Script.toDouble(right));
428 long l = Script.toLong(left) + Script.toLong(right);
429 if(l < Integer.MIN_VALUE || l > Integer.MAX_VALUE) ret = Script.N(l);
430 ret = Script.N((int)l);
434 JS[] args = new JS[count];
435 while(--count >= 0) args[count] = (JS)stack.pop();
436 if(args[0] instanceof JSString) {
437 StringBuffer sb = new StringBuffer(64);
438 for(int i=0;i<args.length;i++) sb.append(Script.toString(args[i]));
439 stack.push(Script.S(sb.toString()));
442 for(int i=0;i<args.length;i++) if(args[i] instanceof JSString) numStrings++;
443 if(numStrings == 0) {
445 for(int i=0;i<args.length;i++) d += Script.toDouble(args[i]);
446 stack.push(Script.N(d));
449 StringBuffer sb = new StringBuffer(64);
450 if(!(args[0] instanceof JSString || args[1] instanceof JSString)) {
453 d += Script.toDouble(args[i++]);
454 } while(!(args[i] instanceof JSString));
455 sb.append(Script.toString(Script.N(d)));
457 while(i < args.length) sb.append(Script.toString(args[i++]));
458 stack.push(Script.S(sb.toString()));
466 JS right = (JS)stack.pop();
467 JS left = (JS)stack.pop();
470 case BITOR: stack.push(Script.N(Script.toLong(left) | Script.toLong(right))); break;
471 case BITXOR: stack.push(Script.N(Script.toLong(left) ^ Script.toLong(right))); break;
472 case BITAND: stack.push(Script.N(Script.toLong(left) & Script.toLong(right))); break;
474 case SUB: stack.push(Script.N(Script.toDouble(left) - Script.toDouble(right))); break;
475 case MUL: stack.push(Script.N(Script.toDouble(left) * Script.toDouble(right))); break;
476 case DIV: stack.push(Script.N(Script.toDouble(left) / Script.toDouble(right))); break;
477 case MOD: stack.push(Script.N(Script.toDouble(left) % Script.toDouble(right))); break;
479 case LSH: stack.push(Script.N(Script.toLong(left) << Script.toLong(right))); break;
480 case RSH: stack.push(Script.N(Script.toLong(left) >> Script.toLong(right))); break;
481 case URSH: stack.push(Script.N(Script.toLong(left) >>> Script.toLong(right))); break;
483 //#repeat </<=/>/>= LT/LE/GT/GE
485 if(left instanceof JSString && right instanceof JSString)
486 stack.push(Script.B(Script.toString(left).compareTo(Script.toString(right)) < 0));
488 stack.push(Script.B(Script.toDouble(left) < Script.toDouble(right)));
495 if(left == null && right == null) ret = true;
496 else if(left == null || right == null) ret = false;
497 else ret = left.jsequals(right);
498 stack.push(Script.B(op == EQ ? ret : !ret)); break;
501 default: throw new Error("unknown opcode " + op);
507 pc--; // it'll get incremented on the next iteration
512 /** tries to find a handler withing the call chain for this exception
513 if a handler is found the interpreter is setup to call the exception handler
514 if a handler is not found the exception is thrown
516 void catchException(JSExn e) throws JSExn {
517 while(!stack.empty()) {
518 JS o = (JS)stack.pop();
519 if (o instanceof CatchMarker || o instanceof TryMarker) {
520 boolean inCatch = o instanceof CatchMarker;
523 if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
525 if(!inCatch && ((TryMarker)o).catchLoc >= 0) {
526 // run the catch block, this will implicitly run the finally block, if it exists
528 stack.push(catchMarker);
529 stack.push(e.getObject());
530 f = ((TryMarker)o).f;
531 scope = ((TryMarker)o).scope;
532 pc = ((TryMarker)o).catchLoc;
535 stack.push(new FinallyData(e));
536 f = ((TryMarker)o).f;
537 scope = ((TryMarker)o).scope;
538 pc = ((TryMarker)o).finallyLoc;
546 void setupTrap(JS.Trap t, JS val, CallMarker cm) throws JSExn {
548 stack.push(new TrapArgs(t, val));
549 f = (JSFunction)t.function(); // FIXME
550 scope = f.parentScope;
555 // Markers //////////////////////////////////////////////////////////////////////
557 static class Marker {}
559 static class CallMarker extends Marker {
563 public CallMarker(Interpreter cx) {
564 pc = cx == null ? -1 : cx.pc + 1;
565 scope = cx == null ? null : cx.scope;
566 f = cx == null ? null : cx.f;
570 static class TrapMarker extends CallMarker {
573 boolean cascadeHappened;
574 final boolean pauseOnPut;
575 public TrapMarker(Interpreter cx, JS.Trap t, JS val) { this(cx,t,val,false); }
576 public TrapMarker(Interpreter cx, JS.Trap t, JS val, boolean pauseOnPut) {
580 this.pauseOnPut = pauseOnPut;
584 static class CatchMarker extends Marker { }
585 private static final CatchMarker catchMarker = new CatchMarker();
587 static class LoopMarker extends Marker {
588 final public int location;
589 final public String label;
590 final public JSScope scope;
591 public LoopMarker(int location, String label, JSScope scope) {
592 this.location = location;
597 static class TryMarker extends Marker {
598 final public int catchLoc;
599 final public int finallyLoc;
600 final public JSScope scope;
601 final public JSFunction f;
602 public TryMarker(int catchLoc, int finallyLoc, Interpreter cx) {
603 this.catchLoc = catchLoc;
604 this.finallyLoc = finallyLoc;
605 this.scope = cx.scope;
609 static class FinallyData extends Marker {
611 final public Object arg;
612 final public JSExn exn;
613 public FinallyData(int op) { this(op,null); }
614 public FinallyData(int op, Object arg) { this.op = op; this.arg = arg; this.exn = null; }
615 public FinallyData(JSExn exn) { this.exn = exn; this.op = -1; this.arg = null; } // Just throw this exn
618 static class TrapArgs extends JS.Immutable {
621 public TrapArgs(Trap t, JS val) { this.t = t; this.val = val; }
622 public JS get(JS key) throws JSExn {
623 if(Script.isInt(key) && Script.toInt(key) == 0) return val;
624 //#switch(Script.str(key))
625 case "trapee": return t.target();
626 case "callee": return t.function();
627 case "trapname": return t.key();
628 case "length": return t.isWriteTrap() ? Script.ONE : Script.ZERO;
630 return super.get(key);
634 static class Stub extends JS.Immutable {
637 public Stub(JS obj, JS method) { this.obj = obj; this.method = method; }
638 public JS call(JS[] args) throws JSExn { return obj.call(method, args); }
641 static final class Stack {
642 private static final int MAX_STACK_SIZE = 512;
643 private Object[] stack = new Object[8];
646 boolean empty() { return sp == 0; }
647 void push(Object o) throws JSExn { if(sp == stack.length) grow(); stack[sp++] = o; }
648 Object peek() { if(sp == 0) throw new RuntimeException("stack underflow"); return stack[sp-1]; }
649 final Object pop() { if(sp == 0) throw new RuntimeException("stack underflow"); return stack[--sp]; }
650 void swap() throws JSExn {
651 if(sp < 2) throw new JSExn("stack overflow");
652 Object tmp = stack[sp-2];
653 stack[sp-2] = stack[sp-1];
656 CallMarker findCall() {
657 for(int i=sp-1;i>=0;i--) if(stack[i] instanceof CallMarker) return (CallMarker) stack[i];
660 void grow() throws JSExn {
661 if(stack.length >= MAX_STACK_SIZE) throw new JSExn("stack overflow");
662 Object[] stack2 = new Object[stack.length * 2];
663 System.arraycopy(stack,0,stack2,0,stack.length);
667 void backtrace(JSExn e) {
668 for(int i=sp-1;i>=0;i--) {
669 if (stack[i] instanceof CallMarker) {
670 CallMarker cm = (CallMarker)stack[i];
671 if(cm.f == null) break;
672 String s = cm.f.sourceName + ":" + cm.f.line[cm.pc-1];
673 if(cm instanceof Interpreter.TrapMarker)
674 s += " (trap on " + Script.str(((Interpreter.TrapMarker)cm).t.key) + ")";