diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/debug/breakpoint-multi-03.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/debug/breakpoint-multi-03.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,27 @@
+// Multiple Debugger objects can set breakpoints at the same instruction.
+
+var g = newGlobal();
+function attach(g, i) {
+    var dbg = Debugger(g);
+    dbg.onDebuggerStatement = function (frame) {
+        var s = frame.eval("f").return.script;
+        var offs = s.getLineOffsets(g.line0 + 3);
+        for (var j = 0; j < offs.length; j++)
+            s.setBreakpoint(offs[j], {hit: function () { g.log += "" + i; }});
+    };
+}
+
+g.eval("var line0 = Error().lineNumber;\n" +
+       "function f() {\n" +     // line0 + 1
+       "    log += 'a';\n" +    // line0 + 2
+       "    log += 'b';\n" +    // line0 + 3
+       "}\n");
+
+for (var i = 0; i < 3; i++)
+    attach(g, i);
+
+g.log = '';
+g.eval('debugger;');
+g.log += 'x';
+g.f();
+assertEq(g.log, 'xa012b');