diff --git a/Python/_warnings.c b/Python/_warnings.c
new file mode 100644
index 0000000..7472ab6
--- /dev/null
+++ b/Python/_warnings.c
@@ -0,0 +1,856 @@
+#include "Python.h"
+#include "frameobject.h"
+
+#define MODULE_NAME "_warnings"
+#define DEFAULT_ACTION_NAME "default_action"
+
+PyDoc_STRVAR(warnings__doc__,
+MODULE_NAME " provides basic warning filtering support.\n"
+"It is a helper module to speed up interpreter start-up.");
+
+/* Both 'filters' and 'onceregistry' can be set in warnings.py;
+   get_warnings_attr() will reset these variables accordingly. */
+static PyObject *_filters;  /* List */
+static PyObject *_once_registry;  /* Dict */
+
+
+static int
+check_matched(PyObject *obj, PyObject *arg)
+{
+    PyObject *result;
+    int rc;
+
+    if (obj == Py_None)
+        return 1;
+    result = PyObject_CallMethod(obj, "match", "O", arg);
+    if (result == NULL)
+        return -1;
+
+    rc = PyObject_IsTrue(result);
+    Py_DECREF(result);
+    return rc;
+}
+
+/*
+   Returns a new reference.
+   A NULL return value can mean false or an error.
+*/
+static PyObject *
+get_warnings_attr(const char *attr)
+{
+    static PyObject *warnings_str = NULL;
+    PyObject *all_modules;
+    PyObject *warnings_module;
+    int result;
+
+    if (warnings_str == NULL) {
+        warnings_str = PyUnicode_InternFromString("warnings");
+        if (warnings_str == NULL)
+            return NULL;
+    }
+
+    all_modules = PyImport_GetModuleDict();
+    result = PyDict_Contains(all_modules, warnings_str);
+    if (result == -1 || result == 0)
+        return NULL;
+
+    warnings_module = PyDict_GetItem(all_modules, warnings_str);
+    if (!PyObject_HasAttrString(warnings_module, attr))
+            return NULL;
+    return PyObject_GetAttrString(warnings_module, attr);
+}
+
+
+PyObject *
+get_once_registry(void)
+{
+    PyObject *registry;
+
+    registry = get_warnings_attr("onceregistry");
+    if (registry == NULL) {
+        if (PyErr_Occurred())
+            return NULL;
+        return _once_registry;
+    }
+    Py_DECREF(_once_registry);
+    _once_registry = registry;
+    return registry;
+}
+
+
+/* The item is a borrowed reference. */
+static const char *
+get_filter(PyObject *category, PyObject *text, Py_ssize_t lineno,
+           PyObject *module, PyObject **item)
+{
+    PyObject *action, *m, *d;
+    Py_ssize_t i;
+    PyObject *warnings_filters;
+
+    warnings_filters = get_warnings_attr("filters");
+    if (warnings_filters == NULL) {
+        if (PyErr_Occurred())
+            return NULL;
+    }
+    else {
+        Py_DECREF(_filters);
+        _filters = warnings_filters;
+    }
+
+    if (!PyList_Check(_filters)) {
+        PyErr_SetString(PyExc_ValueError,
+                        MODULE_NAME ".filters must be a list");
+        return NULL;
+    }
+
+    /* _filters could change while we are iterating over it. */
+    for (i = 0; i < PyList_GET_SIZE(_filters); i++) {
+        PyObject *tmp_item, *action, *msg, *cat, *mod, *ln_obj;
+        Py_ssize_t ln;
+        int is_subclass, good_msg, good_mod;
+
+        tmp_item = *item = PyList_GET_ITEM(_filters, i);
+        if (PyTuple_Size(tmp_item) != 5) {
+            PyErr_Format(PyExc_ValueError,
+                         MODULE_NAME ".filters item %zd isn't a 5-tuple", i);
+            return NULL;
+        }
+
+        /* Python code: action, msg, cat, mod, ln = item */
+        action = PyTuple_GET_ITEM(tmp_item, 0);
+        msg = PyTuple_GET_ITEM(tmp_item, 1);
+        cat = PyTuple_GET_ITEM(tmp_item, 2);
+        mod = PyTuple_GET_ITEM(tmp_item, 3);
+        ln_obj = PyTuple_GET_ITEM(tmp_item, 4);
+
+        good_msg = check_matched(msg, text);
+        good_mod = check_matched(mod, module);
+        is_subclass = PyObject_IsSubclass(category, cat);
+        ln = PyLong_AsSsize_t(ln_obj);
+        if (good_msg == -1 || good_mod == -1 || is_subclass == -1 ||
+            (ln == -1 && PyErr_Occurred()))
+            return NULL;
+
+        if (good_msg && is_subclass && good_mod && (ln == 0 || lineno == ln))
+            return PyUnicode_AsString(action);
+    }
+
+    m = PyImport_ImportModule(MODULE_NAME);
+    if (m == NULL)
+        return NULL;
+    d = PyModule_GetDict(m);
+    Py_DECREF(m);
+    if (d == NULL)
+        return NULL;
+    action = PyDict_GetItemString(d, DEFAULT_ACTION_NAME);
+    if (action != NULL)
+        return PyUnicode_AsString(action);
+
+    PyErr_SetString(PyExc_ValueError,
+                    MODULE_NAME "." DEFAULT_ACTION_NAME " not found");
+    return NULL;
+}
+
+static int
+already_warned(PyObject *registry, PyObject *key, int should_set)
+{
+    PyObject *already_warned;
+
+    if (key == NULL)
+        return -1;
+
+    already_warned = PyDict_GetItem(registry, key);
+    if (already_warned != NULL) {
+        int rc = PyObject_IsTrue(already_warned);
+        if (rc != 0)
+            return rc;
+    }
+
+    /* This warning wasn't found in the registry, set it. */
+    if (should_set)
+        return PyDict_SetItem(registry, key, Py_True);
+    return 0;
+}
+
+/* New reference. */
+static PyObject *
+normalize_module(PyObject *filename)
+{
+    PyObject *module;
+    const char *mod_str;
+    Py_ssize_t len;
+
+    int rc = PyObject_IsTrue(filename);
+    if (rc == -1)
+        return NULL;
+    else if (rc == 0)
+        return PyUnicode_FromString("<unknown>");
+
+    mod_str = PyUnicode_AsString(filename);
+    if (mod_str == NULL)
+	    return NULL;
+    len = PyUnicode_GetSize(filename);
+    if (len < 0)
+        return NULL;
+    if (len >= 3 &&
+	strncmp(mod_str + (len - 3), ".py", 3) == 0) {
+        module = PyUnicode_FromStringAndSize(mod_str, len-3);
+    }
+    else {
+        module = filename;
+        Py_INCREF(module);
+    }
+    return module;
+}
+
+static int
+update_registry(PyObject *registry, PyObject *text, PyObject *category,
+                int add_zero)
+{
+    PyObject *altkey, *zero = NULL;
+    int rc;
+
+    if (add_zero) {
+        zero = PyLong_FromLong(0);
+        if (zero == NULL)
+            return -1;
+        altkey = PyTuple_Pack(3, text, category, zero);
+    }
+    else
+        altkey = PyTuple_Pack(2, text, category);
+
+    rc = already_warned(registry, altkey, 1);
+    Py_XDECREF(zero);
+    Py_XDECREF(altkey);
+    return rc;
+}
+
+static void
+show_warning(PyObject *filename, int lineno, PyObject *text, PyObject
+                *category, PyObject *sourceline)
+{
+    PyObject *f_stderr; 
+    PyObject *name; 
+    char lineno_str[128];
+
+    PyOS_snprintf(lineno_str, sizeof(lineno_str), ":%d: ", lineno);
+
+    name = PyObject_GetAttrString(category, "__name__");
+    if (name == NULL)  /* XXX Can an object lack a '__name__' attribute? */
+	    return;
+
+    f_stderr = PySys_GetObject("stderr");
+    if (f_stderr == NULL) {
+        fprintf(stderr, "lost sys.stderr\n");
+        Py_DECREF(name);
+        return;
+    }
+
+    /* Print "filename:lineno: category: text\n" */
+    PyFile_WriteObject(filename, f_stderr, Py_PRINT_RAW);
+    PyFile_WriteString(lineno_str, f_stderr);
+    PyFile_WriteObject(name, f_stderr, Py_PRINT_RAW);
+    PyFile_WriteString(": ", f_stderr);
+    PyFile_WriteObject(text, f_stderr, Py_PRINT_RAW);
+    PyFile_WriteString("\n", f_stderr);
+    Py_XDECREF(name);
+
+    /* Print "  source_line\n" */
+    PyFile_WriteString("  ", f_stderr);
+    if (sourceline) {
+        char *source_line_str = PyUnicode_AsString(sourceline);
+        while (*source_line_str == ' ' || *source_line_str == '\t' ||
+                *source_line_str == '\014')
+            source_line_str++;
+
+        PyFile_WriteString(source_line_str, f_stderr);
+        PyFile_WriteString("\n", f_stderr);
+    }
+    else
+        Py_DisplaySourceLine(f_stderr, PyUnicode_AsString(filename), lineno);
+    PyErr_Clear();
+}
+
+static PyObject *
+warn_explicit(PyObject *category, PyObject *message, 
+              PyObject *filename, int lineno,
+              PyObject *module, PyObject *registry, PyObject *sourceline)
+{
+    PyObject *key = NULL, *text = NULL, *result = NULL, *lineno_obj = NULL;
+    PyObject *item = Py_None;
+    const char *action;
+    int rc;
+
+    /* Normalize module. */
+    if (module == NULL) {
+        module = normalize_module(filename);
+        if (module == NULL)
+            return NULL;
+    }
+    else
+        Py_INCREF(module);
+
+    /* Normalize message. */
+    Py_INCREF(message);  /* DECREF'ed in cleanup. */
+    rc = PyObject_IsInstance(message, PyExc_Warning);
+    if (rc == -1) {
+        goto cleanup;
+    }
+    if (rc == 1) {
+        text = PyObject_Str(message);
+        category = (PyObject*)message->ob_type;
+    }
+    else {
+        text = message;
+        message = PyObject_CallFunction(category, "O", message);
+    }
+
+    lineno_obj = PyLong_FromLong(lineno);
+    if (lineno_obj == NULL)
+        goto cleanup;
+
+    /* Create key. */
+    key = PyTuple_Pack(3, text, category, lineno_obj);
+    if (key == NULL)
+        goto cleanup;
+
+    if (registry != NULL) {
+        rc = already_warned(registry, key, 0);
+        if (rc == -1)
+            goto cleanup;
+	else if (rc == 1)
+            goto return_none;
+        /* Else this warning hasn't been generated before. */
+    }
+
+    action = get_filter(category, text, lineno, module, &item);
+    if (action == NULL)
+        goto cleanup;
+
+    if (strcmp(action, "error") == 0) {
+        PyErr_SetObject(category, message);
+        goto cleanup;
+    }
+
+    /* Store in the registry that we've been here, *except* when the action
+       is "always". */
+    rc = 0;
+    if (strcmp(action, "always") != 0) {
+        if (registry != NULL && PyDict_SetItem(registry, key, Py_True) < 0)
+            goto cleanup;
+        else if (strcmp(action, "ignore") == 0)
+            goto return_none;
+        else if (strcmp(action, "once") == 0) {
+            if (registry == NULL) {
+                registry = get_once_registry();
+                if (registry == NULL)
+                    goto cleanup;
+            }
+            /* _once_registry[(text, category)] = 1 */
+            rc = update_registry(registry, text, category, 0); 
+        }
+        else if (strcmp(action, "module") == 0) {
+            /* registry[(text, category, 0)] = 1 */
+            if (registry != NULL)
+                rc = update_registry(registry, text, category, 0); 
+        }
+        else if (strcmp(action, "default") != 0) {
+            PyObject *to_str = PyObject_Str(item);
+            const char *err_str = "???";
+
+            if (to_str != NULL)
+                err_str = PyUnicode_AsString(to_str);
+            PyErr_Format(PyExc_RuntimeError,
+                        "Unrecognized action (%s) in warnings.filters:\n %s",
+                        action, err_str);
+            Py_XDECREF(to_str);
+            goto cleanup;
+        }
+    }
+
+    if (rc == 1)  // Already warned for this module. */
+        goto return_none;
+    if (rc == 0) {
+        PyObject *show_fxn = get_warnings_attr("showwarning");
+        if (show_fxn == NULL) {
+            if (PyErr_Occurred())
+                goto cleanup;
+            show_warning(filename, lineno, text, category, sourceline);
+        }
+        else {
+            PyObject *result;
+            
+            result = PyObject_CallFunctionObjArgs(show_fxn, message, category,
+                                                    filename, lineno_obj,
+                                                    Py_None,
+                                                    sourceline ?
+                                                        sourceline: Py_None,
+                                                    NULL);
+            Py_XDECREF(result);
+            if (result == NULL)
+                goto cleanup;
+        }
+    }
+    else /* if (rc == -1) */
+        goto cleanup;
+
+ return_none:
+    result = Py_None;
+    Py_INCREF(result);
+
+ cleanup:
+    Py_XDECREF(key);
+    Py_XDECREF(text);
+    Py_XDECREF(lineno_obj);
+    Py_DECREF(module);
+    Py_DECREF(message);
+    return result;  /* Py_None or NULL. */
+}
+
+/* filename, module, and registry are new refs, globals is borrowed */
+/* Returns 0 on error (no new refs), 1 on success */
+static int
+setup_context(Py_ssize_t stack_level, PyObject **filename, int *lineno,
+              PyObject **module, PyObject **registry)
+{
+    PyObject *globals;
+
+    /* Setup globals and lineno. */
+    PyFrameObject *f = PyThreadState_GET()->frame;
+    while (--stack_level > 0 && f != NULL) {
+        f = f->f_back;
+        --stack_level;
+    }
+
+    if (f == NULL) {
+        globals = PyThreadState_Get()->interp->sysdict;
+        *lineno = 1;
+    }
+    else {
+        globals = f->f_globals;
+        *lineno = PyCode_Addr2Line(f->f_code, f->f_lasti);
+    }
+
+    *module = NULL;
+
+    /* Setup registry. */
+    assert(globals != NULL);
+    assert(PyDict_Check(globals));
+    *registry = PyDict_GetItemString(globals, "__warningregistry__");
+    if (*registry == NULL) {
+        int rc;
+
+        *registry = PyDict_New();
+        if (*registry == NULL)
+            return 0;
+
+         rc = PyDict_SetItemString(globals, "__warningregistry__", *registry);
+         if (rc < 0)
+            goto handle_error;
+    }
+    else
+        Py_INCREF(*registry);
+
+    /* Setup module. */
+    *module = PyDict_GetItemString(globals, "__name__");
+    if (*module == NULL) {
+        *module = PyUnicode_FromString("<string>");
+        if (*module == NULL)
+            goto handle_error;
+    }
+    else
+        Py_INCREF(*module);
+
+    /* Setup filename. */
+    *filename = PyDict_GetItemString(globals, "__file__");
+    if (*filename != NULL) {
+	Py_ssize_t len = PyUnicode_GetSize(*filename);
+        const char *file_str = PyUnicode_AsString(*filename);
+	if (file_str == NULL || (len < 0 && PyErr_Occurred()))
+            goto handle_error;
+
+        /* if filename.lower().endswith((".pyc", ".pyo")): */
+        if (len >= 4 &&
+            file_str[len-4] == '.' &&
+            tolower(file_str[len-3]) == 'p' &&
+            tolower(file_str[len-2]) == 'y' &&
+            (tolower(file_str[len-1]) == 'c' ||
+             tolower(file_str[len-1]) == 'o')) {
+            *filename = PyUnicode_FromStringAndSize(file_str, len-1);
+	    if (*filename == NULL)
+		    goto handle_error;
+	}
+	else
+            Py_INCREF(*filename);
+    }
+    else {
+        const char *module_str = PyUnicode_AsString(*module);
+        if (module_str && strcmp(module_str, "__main__") == 0) {
+            PyObject *argv = PySys_GetObject("argv");
+            if (argv != NULL && PyList_Size(argv) > 0) {
+                *filename = PyList_GetItem(argv, 0);
+                Py_INCREF(*filename);
+            }
+            else {
+                /* embedded interpreters don't have sys.argv, see bug #839151 */
+                *filename = PyUnicode_FromString("__main__");
+	        if (*filename == NULL)
+	            goto handle_error;
+            }
+        }
+        if (*filename == NULL) {
+            *filename = *module;
+            Py_INCREF(*filename);
+        }
+    }
+
+    return 1;
+
+ handle_error:
+    /* filename not XDECREF'ed here as there is no way to jump here with a
+       dangling reference. */
+    Py_XDECREF(*registry);
+    Py_XDECREF(*module);
+    return 0;
+}
+
+static PyObject *
+get_category(PyObject *message, PyObject *category)
+{
+    int rc;
+
+    /* Get category. */
+    rc = PyObject_IsInstance(message, PyExc_Warning);
+    if (rc == -1)
+        return NULL;
+
+    if (rc == 1)
+        category = (PyObject*)message->ob_type;
+    else if (category == NULL)
+        category = PyExc_UserWarning;
+
+    /* Validate category. */
+    rc = PyObject_IsSubclass(category, PyExc_Warning);
+    if (rc == -1)
+        return NULL;
+    if (rc == 0) {
+        PyErr_SetString(PyExc_ValueError,
+                        "category is not a subclass of Warning");
+        return NULL;
+    }
+
+    return category;
+}
+
+static PyObject *
+do_warn(PyObject *message, PyObject *category, Py_ssize_t stack_level)
+{
+    PyObject *filename, *module, *registry, *res;
+    int lineno;
+
+    if (!setup_context(stack_level, &filename, &lineno, &module, &registry))
+        return NULL;
+
+    res = warn_explicit(category, message, filename, lineno, module, registry,
+                        NULL);
+    Py_DECREF(filename);
+    Py_DECREF(registry);
+    Py_DECREF(module);
+    return res;
+}
+
+static PyObject *
+warnings_warn(PyObject *self, PyObject *args, PyObject *kwds)
+{
+    static char *kw_list[] = { "message", "category", "stacklevel", 0 };
+    PyObject *message, *category = NULL;
+    Py_ssize_t stack_level = 1;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|On:warn", kw_list, 
+                                     &message, &category, &stack_level))
+        return NULL;
+
+    category = get_category(message, category);
+    if (category == NULL)
+        return NULL;
+    return do_warn(message, category, stack_level);
+}
+
+static PyObject *
+warnings_warn_explicit(PyObject *self, PyObject *args, PyObject *kwds)
+{
+    static char *kwd_list[] = {"message", "category", "filename", "lineno",
+                                "module", "registry", "module_globals", 0};
+    PyObject *message;
+    PyObject *category;
+    PyObject *filename;
+    int lineno;
+    PyObject *module = NULL;
+    PyObject *registry = NULL;
+    PyObject *module_globals = NULL;
+
+    if (!PyArg_ParseTupleAndKeywords(args, kwds, "OOOi|OOO:warn_explicit",
+                kwd_list, &message, &category, &filename, &lineno, &module,
+                &registry, &module_globals))
+        return NULL;
+
+    if (module_globals) {
+        static PyObject *get_source_name = NULL;
+        static PyObject *splitlines_name = NULL;
+        PyObject *loader;
+        PyObject *module_name;
+        PyObject *source;
+        PyObject *source_list;
+        PyObject *source_line;
+        PyObject *returned;
+
+        if (get_source_name == NULL) {
+            get_source_name = PyUnicode_InternFromString("get_source");
+            if (!get_source_name)
+                return NULL;
+        }
+        if (splitlines_name == NULL) {
+            splitlines_name = PyUnicode_InternFromString("splitlines");
+            if (!splitlines_name)
+                return NULL;
+        }
+
+        /* Check/get the requisite pieces needed for the loader. */
+        loader = PyDict_GetItemString(module_globals, "__loader__");
+        module_name = PyDict_GetItemString(module_globals, "__name__");
+
+        if (loader == NULL || module_name == NULL)
+            goto standard_call;
+
+        /* Make sure the loader implements the optional get_source() method. */
+        if (!PyObject_HasAttrString(loader, "get_source"))
+                goto standard_call;
+        /* Call get_source() to get the source code. */
+        source = PyObject_CallMethodObjArgs(loader, get_source_name,
+                                                module_name, NULL);
+        if (!source)
+            return NULL;
+        else if (source == Py_None) {
+            Py_DECREF(Py_None);
+            goto standard_call;
+        }
+
+        /* Split the source into lines. */
+        source_list = PyObject_CallMethodObjArgs(source, splitlines_name,
+                                                    NULL);
+        Py_DECREF(source);
+        if (!source_list)
+            return NULL;
+
+        /* Get the source line. */
+        source_line = PyList_GetItem(source_list, lineno-1);
+        if (!source_line) {
+            Py_DECREF(source_list);
+            return NULL;
+        }
+
+        /* Handle the warning. */
+        returned = warn_explicit(category, message, filename, lineno, module,
+                            registry, source_line);
+        Py_DECREF(source_list);
+        return returned;
+    }
+
+ standard_call:
+    return warn_explicit(category, message, filename, lineno, module,
+                                registry, NULL);
+}
+
+
+/* Function to issue a warning message; may raise an exception. */
+int
+PyErr_WarnEx(PyObject *category, const char *text, Py_ssize_t stack_level)
+{
+    PyObject *res;
+    PyObject *message = PyUnicode_FromString(text);
+    if (message == NULL)
+        return -1;
+
+    if (category == NULL)
+        category = PyExc_RuntimeWarning;
+
+    res = do_warn(message, category, stack_level);
+    Py_DECREF(message);
+    if (res == NULL)
+        return -1;
+    Py_DECREF(res);
+
+    return 0;
+}
+
+/* PyErr_Warn is only for backwards compatability and will be removed.
+   Use PyErr_WarnEx instead. */
+
+#undef PyErr_Warn
+
+PyAPI_FUNC(int)
+PyErr_Warn(PyObject *category, char *text)
+{
+    return PyErr_WarnEx(category, text, 1);
+}
+
+/* Warning with explicit origin */
+int
+PyErr_WarnExplicit(PyObject *category, const char *text,
+                   const char *filename_str, int lineno,
+                   const char *module_str, PyObject *registry)
+{
+    PyObject *res;
+    PyObject *message = PyUnicode_FromString(text);
+    PyObject *filename = PyUnicode_FromString(filename_str);
+    PyObject *module = NULL;
+    int ret = -1;
+
+    if (message == NULL || filename == NULL)
+        goto exit;
+    if (module_str != NULL) {
+        module = PyUnicode_FromString(module_str);
+            if (module == NULL)
+                goto exit;
+    }
+
+    if (category == NULL)
+        category = PyExc_RuntimeWarning;
+    res = warn_explicit(category, message, filename, lineno, module, registry,
+                        NULL);
+    if (res == NULL)
+        goto exit;
+    Py_DECREF(res);
+    ret = 0;
+
+ exit:
+    Py_XDECREF(message);
+    Py_XDECREF(module);
+    Py_XDECREF(filename);
+    return ret;
+}
+
+
+PyDoc_STRVAR(warn_doc,
+"Issue a warning, or maybe ignore it or raise an exception.");
+
+PyDoc_STRVAR(warn_explicit_doc,
+"Low-level inferface to warnings functionality.");
+
+static PyMethodDef warnings_functions[] = {
+    {"warn", (PyCFunction)warnings_warn, METH_VARARGS | METH_KEYWORDS,
+        warn_doc},
+    {"warn_explicit", (PyCFunction)warnings_warn_explicit,
+        METH_VARARGS | METH_KEYWORDS, warn_explicit_doc},
+    // XXX(brett.cannon): add showwarning?
+    // XXX(brett.cannon): Reasonable to add formatwarning?
+    {NULL, NULL}	        /* sentinel */
+};
+
+
+static PyObject *
+create_filter(PyObject *category, const char *action)
+{
+    static PyObject *ignore_str = NULL;
+    static PyObject *error_str = NULL;
+    static PyObject *default_str = NULL;
+    PyObject *action_obj = NULL;
+    PyObject *lineno, *result;
+
+    if (!strcmp(action, "ignore")) {
+        if (ignore_str == NULL) {
+            ignore_str = PyUnicode_InternFromString("ignore");
+            if (ignore_str == NULL)
+                return NULL;
+        }
+        action_obj = ignore_str;
+    }
+    else if (!strcmp(action, "error")) {
+        if (error_str == NULL) {
+            error_str = PyUnicode_InternFromString("error");
+            if (error_str == NULL)
+                return NULL;
+        }
+        action_obj = error_str;
+    }
+    else if (!strcmp(action, "default")) {
+        if (default_str == NULL) {
+            default_str = PyUnicode_InternFromString("default");
+            if (default_str == NULL)
+                return NULL;
+        }
+        action_obj = default_str;
+    }
+    else {
+        Py_FatalError("unknown action");
+    }
+
+    /* This assumes the line number is zero for now. */
+    lineno = PyLong_FromLong(0);
+    if (lineno == NULL)
+        return NULL;
+    result = PyTuple_Pack(5, action_obj, Py_None, category, Py_None, lineno);
+    Py_DECREF(lineno);
+    return result;
+}
+
+static PyObject *
+init_filters(void)
+{
+    PyObject *filters = PyList_New(3);
+    const char *bytes_action;
+    if (filters == NULL)
+        return NULL;
+
+    PyList_SET_ITEM(filters, 0,
+                    create_filter(PyExc_PendingDeprecationWarning, "ignore"));
+    PyList_SET_ITEM(filters, 1, create_filter(PyExc_ImportWarning, "ignore"));
+    if (Py_BytesWarningFlag > 1)
+        bytes_action = "error";
+    else if (Py_BytesWarningFlag)
+        bytes_action = "default";
+    else
+        bytes_action = "ignore";
+    PyList_SET_ITEM(filters, 2, create_filter(PyExc_BytesWarning,
+                    bytes_action));
+
+    if (PyList_GET_ITEM(filters, 0) == NULL ||
+        PyList_GET_ITEM(filters, 1) == NULL ||
+        PyList_GET_ITEM(filters, 2) == NULL) {
+        Py_DECREF(filters);
+        return NULL;
+    }
+
+    return filters;
+}
+
+
+PyMODINIT_FUNC
+_PyWarnings_Init(void)
+{
+    PyObject *m, *default_action;
+
+    m = Py_InitModule3(MODULE_NAME, warnings_functions, warnings__doc__);
+    if (m == NULL)
+        return;
+
+    _filters = init_filters();
+    if (_filters == NULL)
+        return;
+    Py_INCREF(_filters);
+    if (PyModule_AddObject(m, "filters", _filters) < 0)
+        return;
+
+    _once_registry = PyDict_New();
+    if (_once_registry == NULL)
+        return;
+    Py_INCREF(_once_registry);
+    if (PyModule_AddObject(m, "once_registry", _once_registry) < 0)
+        return;
+
+    default_action = PyUnicode_InternFromString("default");
+    if (default_action == NULL)
+        return;
+    if (PyModule_AddObject(m, DEFAULT_ACTION_NAME, default_action) < 0)
+        return;
+}
diff --git a/Python/errors.c b/Python/errors.c
index cbc6f15..b765b03 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -673,70 +673,6 @@
 
 extern PyObject *PyModule_GetWarningsModule(void);
 
-/* Function to issue a warning message; may raise an exception. */
-int
-PyErr_WarnEx(PyObject *category, const char *message, Py_ssize_t stack_level)
-{
-	PyObject *dict, *func = NULL;
-	PyObject *warnings_module = PyModule_GetWarningsModule();
-
-	if (warnings_module != NULL) {
-		dict = PyModule_GetDict(warnings_module);
-		if (dict != NULL)
-			func = PyDict_GetItemString(dict, "warn");
-	}
-	if (func == NULL) {
-		PySys_WriteStderr("warning: %s\n", message);
-		return 0;
-	}
-	else {
-		PyObject *res;
-
-		if (category == NULL)
-			category = PyExc_RuntimeWarning;
-		res = PyObject_CallFunction(func, "sOn",
-					    message, category, stack_level);
-		if (res == NULL)
-			return -1;
-		Py_DECREF(res);
-		return 0;
-	}
-}
-
-/* Warning with explicit origin */
-int
-PyErr_WarnExplicit(PyObject *category, const char *message,
-		   const char *filename, int lineno,
-		   const char *module, PyObject *registry)
-{
-	PyObject *mod, *dict, *func = NULL;
-
-	mod = PyImport_ImportModuleNoBlock("warnings");
-	if (mod != NULL) {
-		dict = PyModule_GetDict(mod);
-		func = PyDict_GetItemString(dict, "warn_explicit");
-		Py_DECREF(mod);
-	}
-	if (func == NULL) {
-		PySys_WriteStderr("warning: %s\n", message);
-		return 0;
-	}
-	else {
-		PyObject *res;
-
-		if (category == NULL)
-			category = PyExc_RuntimeWarning;
-		if (registry == NULL)
-			registry = Py_None;
-		res = PyObject_CallFunction(func, "sOsizO", message, category,
-					    filename, lineno, module, registry);
-		if (res == NULL)
-			return -1;
-		Py_DECREF(res);
-		return 0;
-	}
-}
-
 
 /* Set file and line information for the current exception.
    If the exception is not a SyntaxError, also sets additional attributes
diff --git a/Python/getopt.c b/Python/getopt.c
index 7c1d605..1baf872 100644
--- a/Python/getopt.c
+++ b/Python/getopt.c
@@ -83,7 +83,18 @@
 
 	if ( (option = *opt_ptr++) == L'\0')
 		return -1;
-	
+
+	if (option == 'J') {
+		fprintf(stderr, "-J is reserved for Jython\n");
+		return '_';
+	}
+
+	if (option == 'X') {
+		fprintf(stderr,
+			"-X is reserved for non-standard arguments\n");
+		return '_';
+	}
+
 	if ((ptr = wcschr(optstring, option)) == NULL) {
 		if (_PyOS_opterr)
 		  fprintf(stderr, "Unknown option: -%c\n", (char)option);
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 08fa79e..a80cb14 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -84,38 +84,12 @@
 int Py_FrozenFlag; /* Needed by getpath.c */
 int Py_IgnoreEnvironmentFlag; /* e.g. PYTHONPATH, PYTHONHOME */
 
-/* Reference to 'warnings' module, to avoid importing it
-   on the fly when the import lock may be held.  See 683658/771097
-*/
-static PyObject *warnings_module = NULL;
-
-/* Returns a borrowed reference to the 'warnings' module, or NULL.
-   If the module is returned, it is guaranteed to have been obtained
-   without acquiring the import lock
-*/
-PyObject *PyModule_GetWarningsModule(void)
+/* PyModule_GetWarningsModule is no longer necessary as of 2.6
+since _warnings is builtin.  This API should not be used. */
+PyObject *
+PyModule_GetWarningsModule(void)
 {
-	PyObject *typ, *val, *tb;
-	PyObject *all_modules;
-	/* If we managed to get the module at init time, just use it */
-	if (warnings_module)
-		return warnings_module;
-	/* If it wasn't available at init time, it may be available
-	   now in sys.modules (common scenario is frozen apps: import
-	   at init time fails, but the frozen init code sets up sys.path
-	   correctly, then does an implicit import of warnings for us
-	*/
-	/* Save and restore any exceptions */
-	PyErr_Fetch(&typ, &val, &tb);
-
-	all_modules = PySys_GetObject("modules");
-	if (all_modules) {
-		warnings_module = PyDict_GetItemString(all_modules, "warnings");
-		/* We keep a ref in the global */
-		Py_XINCREF(warnings_module);
-	}
-	PyErr_Restore(typ, val, tb);
-	return warnings_module;
+	return PyImport_ImportModule("warnings");
 }
 
 static int initialized = 0;
@@ -255,6 +229,15 @@
 
 	if (install_sigs)
 		initsigs(); /* Signal handling stuff, including initintr() */
+		
+    /* Initialize warnings. */
+    _PyWarnings_Init();
+    if (PySys_HasWarnOptions()) {
+        PyObject *warnings_module = PyImport_ImportModule("warnings");
+        if (!warnings_module)
+            PyErr_Clear();
+        Py_XDECREF(warnings_module);
+    }
 
 	initmain(); /* Module __main__ */
 	if (initstdio() < 0)
@@ -268,30 +251,6 @@
 	_PyGILState_Init(interp, tstate);
 #endif /* WITH_THREAD */
 
-	warnings_module = PyImport_ImportModule("warnings");
-	if (!warnings_module) {
-		PyErr_Clear();
-	}
-	else {
-		PyObject *o;
-		char *action[8];
-
-		if (Py_BytesWarningFlag > 1)
-			*action = "error";
-		else if (Py_BytesWarningFlag)
-			*action = "default";
-		else
-			*action = "ignore";
-
-		o = PyObject_CallMethod(warnings_module,
-					"simplefilter", "sO",
-					*action, PyExc_BytesWarning);
-		if (o == NULL)
-			Py_FatalError("Py_Initialize: can't initialize"
-				      "warning filter for BytesWarning.");
-		Py_DECREF(o);
-        }
-
 #if defined(HAVE_LANGINFO_H) && defined(CODESET)
 	/* On Unix, set the file system encoding according to the
 	   user's preference, if the CODESET names a well-known
@@ -403,10 +362,6 @@
 	/* Disable signal handling */
 	PyOS_FiniInterrupts();
 
-	/* drop module references we saved */
-	Py_XDECREF(warnings_module);
-	warnings_module = NULL;
-
 	/* Clear type lookup cache */
 	PyType_ClearCache();
 
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 81adf5d..9337f5c 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -899,6 +899,12 @@
 	}
 }
 
+int
+PySys_HasWarnOptions(void)
+{
+    return (warnoptions != NULL && (PyList_Size(warnoptions) > 0)) ? 1 : 0;
+}
+
 /* XXX This doc string is too long to be a single string literal in VC++ 5.0.
    Two literals concatenated works just fine.  If you have a K&R compiler
    or other abomination that however *does* understand longer strings,
@@ -1101,6 +1107,7 @@
 #endif
 	/* {"unbuffered",		"-u"}, */
 	/* {"skip_first",		"-x"}, */
+	{"bytes_warning", "-b"},
 	{0}
 };
 
@@ -1144,6 +1151,7 @@
 #endif
 	/* SetFlag(saw_unbuffered_flag); */
 	/* SetFlag(skipfirstline); */
+    SetFlag(Py_BytesWarningFlag);
 #undef SetFlag
 
 	if (PyErr_Occurred()) {
diff --git a/Python/traceback.c b/Python/traceback.c
index be55aa9..e46e67d 100644
--- a/Python/traceback.c
+++ b/Python/traceback.c
@@ -128,16 +128,16 @@
 	return 0;
 }
 
-static int
-tb_displayline(PyObject *f, char *filename, int lineno, char *name)
+int
+Py_DisplaySourceLine(PyObject *f, const char *filename, int lineno)
 {
 	int err = 0;
-	FILE *xfp;
+	FILE *xfp = NULL;
 	char linebuf[2000];
 	int i;
 	char namebuf[MAXPATHLEN+1];
 
-	if (filename == NULL || name == NULL)
+	if (filename == NULL)
 		return -1;
 	/* This is needed by Emacs' compile command */
 #define FMT "  File \"%.500s\", line %d, in %.500s\n"
@@ -145,7 +145,7 @@
 	if (xfp == NULL) {
 		/* Search tail of filename in sys.path before giving up */
 		PyObject *path;
-		char *tail = strrchr(filename, SEP);
+		const char *tail = strrchr(filename, SEP);
 		if (tail == NULL)
 			tail = filename;
 		else
@@ -181,14 +181,14 @@
 			}
 		}
 	}
-	PyOS_snprintf(linebuf, sizeof(linebuf), FMT, filename, lineno, name);
-	err = PyFile_WriteString(linebuf, f);
-	if (xfp == NULL)
-		return err;
-	else if (err != 0) {
-		fclose(xfp);
-		return err;
-	}
+
+        if (xfp == NULL)
+            return err;
+        if (err != 0) {
+            fclose(xfp);
+            return err;
+        }
+
 	for (i = 0; i < lineno; i++) {
 		char* pLastChar = &linebuf[sizeof(linebuf)-2];
 		do {
@@ -206,22 +206,38 @@
 		char *p = linebuf;
 		while (*p == ' ' || *p == '\t' || *p == '\014')
 			p++;
-		err = PyFile_WriteString("    ", f);
-		if (err == 0) {
-			err = PyFile_WriteString(p, f);
-			if (err == 0 && strchr(p, '\n') == NULL)
-				err = PyFile_WriteString("\n", f);
-		}
+                    err = PyFile_WriteString(p, f);
+                    if (err == 0 && strchr(p, '\n') == NULL)
+                            err = PyFile_WriteString("\n", f);
 	}
 	fclose(xfp);
 	return err;
 }
 
 static int
-tb_printinternal(PyTracebackObject *tb, PyObject *f, int limit)
+tb_displayline(PyObject *f, const char *filename, int lineno, const char *name)
 {
 	int err = 0;
-	int depth = 0;
+        char linebuf[2000];
+
+	if (filename == NULL || name == NULL)
+		return -1;
+	/* This is needed by Emacs' compile command */
+#define FMT "  File \"%.500s\", line %d, in %.500s\n"
+	PyOS_snprintf(linebuf, sizeof(linebuf), FMT, filename, lineno, name);
+	err = PyFile_WriteString(linebuf, f);
+	if (err != 0)
+		return err;
+
+        err = PyFile_WriteString("    ", f);
+        return Py_DisplaySourceLine(f, filename, lineno);
+}
+
+static int
+tb_printinternal(PyTracebackObject *tb, PyObject *f, long limit)
+{
+	int err = 0;
+	long depth = 0;
 	PyTracebackObject *tb1 = tb;
 	while (tb1 != NULL) {
 		depth++;
@@ -250,7 +266,7 @@
 {
 	int err;
 	PyObject *limitv;
-	int limit = PyTraceBack_LIMIT;
+	long limit = PyTraceBack_LIMIT;
 
 	if (v == NULL)
 		return 0;