diff -r 000000000000 -r 6474c204b198 js/src/gdb/gdb-tests.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/gdb/gdb-tests.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,104 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "gdb-tests.h"
+#include "jsapi.h"
+#include "jsfriendapi.h"
+
+using namespace JS;
+
+/* The class of the global object. */
+const JSClass global_class = {
+    "global", JSCLASS_GLOBAL_FLAGS,
+    JS_PropertyStub,  JS_DeletePropertyStub, JS_PropertyStub,  JS_StrictPropertyStub,
+    JS_EnumerateStub, JS_ResolveStub, JS_ConvertStub,
+    nullptr, nullptr, nullptr, nullptr,
+    JS_GlobalObjectTraceHook
+};
+
+template<typename T>
+static inline T *
+checkPtr(T *ptr)
+{
+  if (! ptr)
+    abort();
+  return ptr;
+}
+
+static void
+checkBool(bool success)
+{
+  if (! success)
+    abort();
+}
+
+/* The error reporter callback. */
+void reportError(JSContext *cx, const char *message, JSErrorReport *report)
+{
+    fprintf(stderr, "%s:%u: %s\n",
+            report->filename ? report->filename : "<no filename>",
+            (unsigned int) report->lineno,
+            message);
+}
+
+// prolog.py sets a breakpoint on this function; test functions can call it
+// to easily return control to GDB where desired.
+void breakpoint() {
+    // If we leave this function empty, the linker will unify it with other
+    // empty functions throughout SpiderMonkey. If we then set a GDB
+    // breakpoint on it, that breakpoint will hit at all sorts of random
+    // times. So make it perform a distinctive side effect.
+    fprintf(stderr, "Called " __FILE__ ":breakpoint\n");
+}
+
+GDBFragment *GDBFragment::allFragments = nullptr;
+
+int
+main (int argc, const char **argv)
+{
+    if (!JS_Init()) return 1;
+    JSRuntime *runtime = checkPtr(JS_NewRuntime(1024 * 1024, JS_USE_HELPER_THREADS));
+    JS_SetGCParameter(runtime, JSGC_MAX_BYTES, 0xffffffff);
+    JS_SetNativeStackQuota(runtime, 5000000);
+
+    JSContext *cx = checkPtr(JS_NewContext(runtime, 8192));
+    JS_SetErrorReporter(cx, reportError);
+
+    JSAutoRequest ar(cx);
+
+    /* Create the global object. */
+    JS::CompartmentOptions options;
+    options.setVersion(JSVERSION_LATEST);
+    RootedObject global(cx, checkPtr(JS_NewGlobalObject(cx, &global_class,
+                        nullptr, JS::FireOnNewGlobalHook, options)));
+    js::SetDefaultObjectForContext(cx, global);
+
+    JSAutoCompartment ac(cx, global);
+
+    /* Populate the global object with the standard globals,
+       like Object and Array. */
+    checkBool(JS_InitStandardClasses(cx, global));
+
+    argv++;
+    while (*argv) {
+        const char *name = *argv++;
+        GDBFragment *fragment;
+        for (fragment = GDBFragment::allFragments; fragment; fragment = fragment->next) {
+            if (strcmp(fragment->name(), name) == 0) {
+                fragment->run(cx, argv);
+                break;
+            }
+        }
+        if (!fragment) {
+            fprintf(stderr, "Unrecognized fragment name: %s\n", name);
+            exit(1);
+        }
+    }
+
+    return 0;
+}