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(JSU.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 (JSU.toBoolean((JS)stack.pop())) pc += JSU.toInt((JS)arg) - 1; break;
113 case JF: if (!JSU.toBoolean((JS)stack.pop())) pc += JSU.toInt((JS)arg) - 1; break;
114 case JMP: pc += JSU.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 = JSU.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, (JS)stack.peek()); break;
127 case ASSERT: if (!JSU.toBoolean((JS)stack.pop())) throw je("ibex.assertion.failed"); break;
128 case BITNOT: stack.push(JSU.N(~JSU.toLong((JS)stack.pop()))); break;
129 case BANG: stack.push(JSU.B(!JSU.toBoolean((JS)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(JSU.S("string"));
137 else if (o instanceof JSNumber.B) stack.push(JSU.S("boolean"));
138 else if (o instanceof JSNumber) stack.push(JSU.S("number"));
139 else stack.push(JSU.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));
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 = JSU.toInt((JS)f.arg[loopInstructionLocation]) + loopInstructionLocation;
170 scope = ((LoopMarker)o).scope;
171 if (op == CONTINUE) { stack.push(o); stack.push(JSU.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 && !JSU.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 = JSU.toBoolean((JS)arg);
240 JS val = write ? (JS)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 " + JSU.str(val) + " to the " + JSU.str(key) + " property on the null value");
280 if (key == null) throw je("tried to assign \"" + JSU.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 " + JSU.str(target));
316 if (target == null) throw je("tried to get property \"" + JSU.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 // FIXME: can a lot of simple cases in Parser be
342 // reduced so creating a new JS[] is not necessary?
344 if (arg instanceof JSNumber.I) {
345 jsargs = new JS[((JSNumber.I)arg).toInt()];
346 for (int i=0; i < jsargs.length; i++) jsargs[i] = (JS)stack.pop();
347 } else jsargs = (JS[])arg;
351 JS object = (JS)stack.pop();
353 if (op == CALLMETHOD) {
354 if (object == null) {
355 method = (JS)stack.pop();
356 object = (JS)stack.pop();
357 throw new JSExn("function '"+JSU.str(method)+"' not found in " + object.getClass().getName());
358 } else if (object instanceof JS.Method) {
359 method = (JS)stack.pop();
360 object = (JS)stack.pop();
367 if (object instanceof JSFunction) {
368 stack.push(new CallMarker(this));
370 f = (JSFunction)object;
371 scope = f.parentScope;
376 ret = method == null ? c.call(jsargs) : c.call(method, jsargs);
379 if (pausecount > initialPauseCount) { pc++; return null; }
385 throw new JSExn((JS)stack.pop(), this);
389 final Grammar r = (Grammar)arg;
390 final JSScope final_scope = scope;
391 Grammar r2 = new Grammar() {
392 public int match(String s, int start, Map v, JSScope scope) throws JSExn {
393 return r.match(s, start, v, final_scope);
395 public int matchAndWrite(String s, int start, Map v, JSScope scope, String key) throws JSExn {
396 return r.matchAndWrite(s, start, v, final_scope, key);
398 public Object call(Object a0, Object a1, Object a2, Object[] rest, int nargs) throws JSExn {
400 r.matchAndWrite((String)a0, 0, v, final_scope, "foo");
404 Object obj = stack.pop();
405 if (obj != null && obj instanceof Grammar) r2 = new Grammar.Alternative((Grammar)obj, r2);
410 case ADD_TRAP: case DEL_TRAP: {
411 JS val = (JS)stack.pop();
412 JS key = (JS)stack.pop();
413 JS js = (JS)stack.peek();
414 // A trap addition/removal
415 if(!(val instanceof JSFunction)) throw new JSExn("tried to add/remove a non-function trap"); // FIXME
416 if(op == ADD_TRAP) js.addTrap(key, val);
417 else js.delTrap(key, val);
422 int count = ((JSNumber)arg).toInt();
423 if(count < 2) throw new Error("this should never happen");
426 JS right = (JS)stack.pop();
427 JS left = (JS)stack.pop();
429 if(left instanceof JSString || right instanceof JSString)
430 ret = JSU.S(JSU.toString(left).concat(JSU.toString(right)));
431 else if(left instanceof JSNumber.D || right instanceof JSNumber.D)
432 ret = JSU.N(JSU.toDouble(left) + JSU.toDouble(right));
434 long l = JSU.toLong(left) + JSU.toLong(right);
435 if(l < Integer.MIN_VALUE || l > Integer.MAX_VALUE) ret = JSU.N(l);
440 JS[] args = new JS[count];
441 while(--count >= 0) args[count] = (JS)stack.pop();
442 if(args[0] instanceof JSString) {
443 StringBuffer sb = new StringBuffer(64);
444 for(int i=0;i<args.length;i++) sb.append(JSU.toString(args[i]));
445 stack.push(JSU.S(sb.toString()));
448 for(int i=0;i<args.length;i++) if(args[i] instanceof JSString) numStrings++;
449 if(numStrings == 0) {
451 for(int i=0;i<args.length;i++) d += JSU.toDouble(args[i]);
452 stack.push(JSU.N(d));
455 StringBuffer sb = new StringBuffer(64);
456 if(!(args[0] instanceof JSString || args[1] instanceof JSString)) {
459 d += JSU.toDouble(args[i++]);
460 } while(!(args[i] instanceof JSString));
461 sb.append(JSU.toString(JSU.N(d)));
463 while(i < args.length) sb.append(JSU.toString(args[i++]));
464 stack.push(JSU.S(sb.toString()));
472 JS right = (JS)stack.pop();
473 JS left = (JS)stack.pop();
476 case BITOR: stack.push(JSU.N(JSU.toLong(left) | JSU.toLong(right))); break;
477 case BITXOR: stack.push(JSU.N(JSU.toLong(left) ^ JSU.toLong(right))); break;
478 case BITAND: stack.push(JSU.N(JSU.toLong(left) & JSU.toLong(right))); break;
480 case SUB: stack.push(JSU.N(JSU.toDouble(left) - JSU.toDouble(right))); break;
481 case MUL: stack.push(JSU.N(JSU.toDouble(left) * JSU.toDouble(right))); break;
482 case DIV: stack.push(JSU.N(JSU.toDouble(left) / JSU.toDouble(right))); break;
483 case MOD: stack.push(JSU.N(JSU.toDouble(left) % JSU.toDouble(right))); break;
485 case LSH: stack.push(JSU.N(JSU.toLong(left) << JSU.toLong(right))); break;
486 case RSH: stack.push(JSU.N(JSU.toLong(left) >> JSU.toLong(right))); break;
487 case URSH: stack.push(JSU.N(JSU.toLong(left) >>> JSU.toLong(right))); break;
489 //#repeat </<=/>/>= LT/LE/GT/GE
491 if(left instanceof JSString && right instanceof JSString)
492 stack.push(JSU.B(JSU.toString(left).compareTo(JSU.toString(right)) < 0));
494 stack.push(JSU.B(JSU.toDouble(left) < JSU.toDouble(right)));
501 if(left == null && right == null) ret = true;
502 else if(left == null || right == null) ret = false;
503 else ret = left.equals(right);
504 stack.push(JSU.B(op == EQ ? ret : !ret)); break;
507 default: throw new Error("unknown opcode " + op);
513 pc--; // it'll get incremented on the next iteration
518 /** tries to find a handler withing the call chain for this exception
519 if a handler is found the interpreter is setup to call the exception handler
520 if a handler is not found the exception is thrown
522 void catchException(JSExn e) throws JSExn {
523 while(!stack.empty()) {
524 Object o = stack.pop();
525 if (o instanceof CatchMarker || o instanceof TryMarker) {
526 boolean inCatch = o instanceof CatchMarker;
529 if(((TryMarker)o).finallyLoc < 0) continue; // no finally block, keep going
531 if(!inCatch && ((TryMarker)o).catchLoc >= 0) {
532 // run the catch block, this will implicitly run the finally block, if it exists
534 stack.push(catchMarker);
535 stack.push(e.getObject());
536 f = ((TryMarker)o).f;
537 scope = ((TryMarker)o).scope;
538 pc = ((TryMarker)o).catchLoc;
541 stack.push(new FinallyData(e));
542 f = ((TryMarker)o).f;
543 scope = ((TryMarker)o).scope;
544 pc = ((TryMarker)o).finallyLoc;
552 void setupTrap(JS.Trap t, JS val, CallMarker cm) throws JSExn {
554 stack.push(new TrapArgs(t, val));
555 f = (JSFunction)t.function(); // FIXME
556 scope = f.parentScope;
561 // Markers //////////////////////////////////////////////////////////////////////
563 static class Marker {}
565 static class CallMarker extends Marker {
569 public CallMarker(Interpreter cx) {
570 pc = cx == null ? -1 : cx.pc + 1;
571 scope = cx == null ? null : cx.scope;
572 f = cx == null ? null : cx.f;
576 static class TrapMarker extends CallMarker {
579 boolean cascadeHappened;
580 final boolean pauseOnPut;
581 public TrapMarker(Interpreter cx, JS.Trap t, JS val) { this(cx,t,val,false); }
582 public TrapMarker(Interpreter cx, JS.Trap t, JS val, boolean pauseOnPut) {
586 this.pauseOnPut = pauseOnPut;
590 static class CatchMarker extends Marker { }
591 private static final CatchMarker catchMarker = new CatchMarker();
593 static class LoopMarker extends Marker {
594 final public int location;
595 final public String label;
596 final public JSScope scope;
597 public LoopMarker(int location, String label, JSScope scope) {
598 this.location = location;
603 static class TryMarker extends Marker {
604 final public int catchLoc;
605 final public int finallyLoc;
606 final public JSScope scope;
607 final public JSFunction f;
608 public TryMarker(int catchLoc, int finallyLoc, Interpreter cx) {
609 this.catchLoc = catchLoc;
610 this.finallyLoc = finallyLoc;
611 this.scope = cx.scope;
615 static class FinallyData extends Marker {
617 final public Object arg;
618 final public JSExn exn;
619 public FinallyData(int op) { this(op,null); }
620 public FinallyData(int op, Object arg) { this.op = op; this.arg = arg; this.exn = null; }
621 public FinallyData(JSExn exn) { this.exn = exn; this.op = -1; this.arg = null; } // Just throw this exn
624 static class TrapArgs extends JS.Immutable {
627 public TrapArgs(Trap t, JS val) { this.t = t; this.val = val; }
628 public JS get(JS key) throws JSExn {
629 if(JSU.isInt(key) && JSU.toInt(key) == 0) return val;
630 //#switch(JSU.str(key))
631 case "trapee": return t.target();
632 case "callee": return t.function();
633 case "trapname": return t.key();
634 case "length": return t.isWriteTrap() ? JSU.ONE : JSU.ZERO;
636 return super.get(key);
640 static class Stub extends JS.Immutable {
643 public Stub(JS obj, JS method) { this.obj = obj; this.method = method; }
644 public JS call(JS[] args) throws JSExn { return obj.call(method, args); }
647 static final class Stack {
648 private static final int MAX_STACK_SIZE = 512;
649 private Object[] stack = new Object[8];
652 boolean empty() { return sp == 0; }
653 void push(Object o) throws JSExn { if(sp == stack.length) grow(); stack[sp++] = o; }
654 Object peek() { if(sp == 0) throw new RuntimeException("stack underflow"); return stack[sp-1]; }
655 final Object pop() { if(sp == 0) throw new RuntimeException("stack underflow"); return stack[--sp]; }
656 void swap() throws JSExn {
657 if(sp < 2) throw new JSExn("stack overflow");
658 Object tmp = stack[sp-2];
659 stack[sp-2] = stack[sp-1];
662 CallMarker findCall() {
663 for(int i=sp-1;i>=0;i--) if(stack[i] instanceof CallMarker) return (CallMarker) stack[i];
666 void grow() throws JSExn {
667 if(stack.length >= MAX_STACK_SIZE) throw new JSExn("stack overflow");
668 Object[] stack2 = new Object[stack.length * 2];
669 System.arraycopy(stack,0,stack2,0,stack.length);
673 void backtrace(JSExn e) {
674 for(int i=sp-1;i>=0;i--) {
675 if (stack[i] instanceof CallMarker) {
676 CallMarker cm = (CallMarker)stack[i];
677 if(cm.f == null) break;
678 String s = cm.f.sourceName + ":" + cm.f.line[cm.pc-1];
679 if(cm instanceof Interpreter.TrapMarker)
680 s += " (trap on " + JSU.str(((Interpreter.TrapMarker)cm).t.key()) + ")";