jsexn on stack overflow

[org.ibex.core.git] / src / org / ibex / js / Interpreter.java

diff --git a/src/org/ibex/js/Interpreter.java b/src/org/ibex/js/Interpreter.java
index 983b471..6fc2859 100644 (file)
--- a/src/org/ibex/js/Interpreter.java
+++ b/src/org/ibex/js/Interpreter.java
@@ -6,7 +6,7 @@ import java.util.*;
 
 /** Encapsulates a single JS interpreter (ie call stack) */
 class Interpreter implements ByteCodes, Tokens {
-
+    private static final int MAX_STACK_SIZE = 512;
 
     // Thread-Interpreter Mapping /////////////////////////////////////////////////////////////////////////
 
@@ -236,9 +236,6 @@ class Interpreter implements ByteCodes, Tokens {
                     while (t != null && t.f.numFormalArgs == 0) t = t.next;
                     if (t == null) { target = ts.t.trapee; key = ts.t.name; }
 
-                } else if (target instanceof Trap.TrapScope && key.equals(((Trap.TrapScope)target).t.name)) {
-                    throw je("tried to put to " + key + " inside a trap it owns; use cascade instead"); 
-
                 } else if (target instanceof JS) {
                     if (target instanceof JSScope) {
                         JSScope p = (JSScope)target; // search the scope-path for the trap
@@ -251,6 +248,7 @@ class Interpreter implements ByteCodes, Tokens {
                 }
                 if (t != null) {
                     stack.push(new CallMarker(this));
+                    if(stack.size() > MAX_STACK_SIZE) throw new JSExn("stack overflow");
                     JSArray args = new JSArray();
                     args.addElement(val);
                     stack.push(args);
@@ -302,6 +300,7 @@ class Interpreter implements ByteCodes, Tokens {
                     }
                     if (t != null) {
                         stack.push(new CallMarker(this));
+                        if(stack.size() > MAX_STACK_SIZE) throw new JSExn("stack overflow");
                         JSArray args = new JSArray();
                         stack.push(args);
                         f = t.f;
@@ -352,6 +351,7 @@ class Interpreter implements ByteCodes, Tokens {
                     JSArray arguments = new JSArray();
                     for(int i=0; i<numArgs; i++) arguments.addElement(i==0?a0:i==1?a1:i==2?a2:rest[i-3]);
                     stack.push(new CallMarker(this));
+                    if(stack.size() > MAX_STACK_SIZE) throw new JSExn("stack overflow");
                     stack.push(arguments);
                     f = (JSFunction)object;
                     scope = new JSScope(f.parentScope);
@@ -402,7 +402,17 @@ class Interpreter implements ByteCodes, Tokens {
                 Object key = stack.pop();
                 Object obj = stack.peek();
                 // A trap addition/removal
-                JS js = obj instanceof JSScope ? ((JSScope)obj).top() : (JS) obj;
+                JS js = (JS) obj;
+                if(js instanceof JSScope) {
+                    JSScope s = (JSScope) js;
+                    while(s.getParentScope() != null) {
+                        if(s.has(key)) throw new JSExn("cannot trap a variable that isn't at the top level scope");
+                        s = s.getParentScope();
+                    }
+                    js = s;
+                }
+                // might want this?
+                // if(!js.has(key)) throw new JSExn("tried to add/remove a trap from an uninitialized variable");
                 if(op == ADD_TRAP) js.addTrap(key, (JSFunction)val);
                 else js.delTrap(key, (JSFunction)val);
                 break;