michael@0: // Storing a Debugger.Object as a key in a WeakMap protects it from GC as long as
michael@0: // the referent is alive.
michael@0: 
michael@0: var g = newGlobal();
michael@0: var N = g.N = 10;
michael@0: var dbg = Debugger(g);
michael@0: var cache = new WeakMap;
michael@0: 
michael@0: var i = 0;
michael@0: dbg.onDebuggerStatement = function (frame) {
michael@0:     cache.set(frame.arguments[0], i++);
michael@0: };
michael@0: g.eval("function f(x) { debugger; }");
michael@0: g.eval("var arr = [], j; for (j = 0; j < N; j++) arr[j] = {};");
michael@0: g.eval("for (j = 0; j < N; j++) f(arr[j]);");
michael@0: assertEq(i, N);
michael@0: 
michael@0: gc(); gc();
michael@0: 
michael@0: i = 0;
michael@0: dbg.onDebuggerStatement = function (frame) {
michael@0:     assertEq(cache.get(frame.arguments[0]), i++)
michael@0: };
michael@0: g.eval("for (j = 0; j < N; j++) f(arr[j]);");
michael@0: assertEq(i, N);