Add API for static strings, primarily good for identifiers.

Thanks to Konrad Schöbel and Jasper Schulz for helping with the mass-editing.

50 files changed, 571 insertions, 233 deletions

diff --git a/Include/abstract.h b/Include/abstract.h
index 0fe0956..3946ec5 100644
--- a/Include/abstract.h
+++ b/Include/abstract.h
@@ -7,6 +7,7 @@ extern "C" {
 #ifdef PY_SSIZE_T_CLEAN
 #define PyObject_CallFunction _PyObject_CallFunction_SizeT
 #define PyObject_CallMethod _PyObject_CallMethod_SizeT
+#define _PyObject_CallMethodId _PyObject_CallMethodId_SizeT
 #endif
 
 /* Abstract Object Interface (many thanks to Jim Fulton) */
@@ -307,11 +308,22 @@ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
      Python expression: o.method(args).
        */
 
+     PyAPI_FUNC(PyObject *) _PyObject_CallMethodId(PyObject *o, _Py_Identifier *method,
+                                                  char *format, ...);
+
+       /*
+         Like PyObject_CallMethod, but expect a _Py_Identifier* as the
+         method name.
+       */
+
      PyAPI_FUNC(PyObject *) _PyObject_CallFunction_SizeT(PyObject *callable,
                                                          char *format, ...);
      PyAPI_FUNC(PyObject *) _PyObject_CallMethod_SizeT(PyObject *o,
                                                        char *name,
                                                        char *format, ...);
+     PyAPI_FUNC(PyObject *) _PyObject_CallMethodId_SizeT(PyObject *o,
+                                                       _Py_Identifier *name,
+                                                       char *format, ...);
 
      PyAPI_FUNC(PyObject *) PyObject_CallFunctionObjArgs(PyObject *callable,
                                                          ...);
diff --git a/Include/object.h b/Include/object.h
index e0c68c1..cf231af 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -454,6 +454,7 @@ PyAPI_FUNC(unsigned int) PyType_ClearCache(void);
 PyAPI_FUNC(void) PyType_Modified(PyTypeObject *);
 
 /* Generic operations on objects */
+struct _Py_Identifier;
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(int) PyObject_Print(PyObject *, FILE *, int);
 PyAPI_FUNC(void) _Py_BreakPoint(void);
@@ -471,6 +472,9 @@ PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *);
 PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *);
 PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *);
 PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *);
+PyAPI_FUNC(PyObject *) _PyObject_GetAttrId(PyObject *, struct _Py_Identifier *);
+PyAPI_FUNC(int) _PyObject_SetAttrId(PyObject *, struct _Py_Identifier *, PyObject *);
+PyAPI_FUNC(int) _PyObject_HasAttrId(PyObject *, struct _Py_Identifier *);
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(PyObject **) _PyObject_GetDictPtr(PyObject *);
 #endif
diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
index 5144234..f90e0bd 100644
--- a/Include/unicodeobject.h
+++ b/Include/unicodeobject.h
@@ -2024,6 +2024,40 @@ PyAPI_FUNC(int) _PyUnicode_CheckConsistency(
     int check_content);
 #endif
 
+/********************* String Literals ****************************************/
+/* This structure helps managing static strings. The basic usage goes like this:
+   Instead of doing
+
+       r = PyObject_CallMethod(o, "foo", "args", ...);
+
+   do
+
+       _Py_identifier(foo);
+       ...
+       r = _PyObject_CallMethodId(o, &PyId_foo, "args", ...);
+
+   PyId_foo is a static variable, either on block level or file level. On first
+   usage, the string "foo" is interned, and the structures are linked. On interpreter
+   shutdown, all strings are released (through _PyUnicode_ClearStaticStrings).
+
+   Alternatively, _Py_static_string allows to choose the variable name.
+   _PyUnicode_FromId returns a new reference to the interned string.
+   _PyObject_{Get,Set,Has}AttrId are __getattr__ versions using _Py_Identifier*.
+*/
+typedef struct _Py_Identifier {
+    struct _Py_Identifier *next;
+    const char* string;
+    PyObject *object;
+} _Py_Identifier;
+
+#define _Py_static_string(varname, value)  static _Py_Identifier varname = { 0, value, 0 };
+#define _Py_identifier(varname) _Py_static_string(PyId_##varname, #varname)
+
+/* Return an interned Unicode object for an Identifier; may fail if there is no memory.*/
+PyAPI_FUNC(PyObject*) _PyUnicode_FromId(_Py_Identifier*);
+/* Clear all static strings. */
+PyAPI_FUNC(void) _PyUnicode_ClearStaticStrings(void);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/Misc/NEWS b/Misc/NEWS
index 26a98f4..b4dbd6e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,8 @@ What's New in Python 3.3 Alpha 1?
 Core and Builtins
 -----------------
 
+- Add internal API for static strings (_Py_identifier et.al.).
+
 - Issue #13063: the Windows error ERROR_NO_DATA (numbered 232 and described
   as "The pipe is being closed") is now mapped to POSIX errno EPIPE
   (previously EINVAL).
diff --git a/Modules/_bisectmodule.c b/Modules/_bisectmodule.c
index 7fecfc6..9da255e 100644
--- a/Modules/_bisectmodule.c
+++ b/Modules/_bisectmodule.c
@@ -86,7 +86,9 @@ insort_right(PyObject *self, PyObject *args, PyObject *kw)
         if (PyList_Insert(list, index, item) < 0)
             return NULL;
     } else {
-        result = PyObject_CallMethod(list, "insert", "nO", index, item);
+        _Py_identifier(insert);
+
+        result = _PyObject_CallMethodId(list, &PyId_insert, "nO", index, item);
         if (result == NULL)
             return NULL;
         Py_DECREF(result);
@@ -186,7 +188,9 @@ insort_left(PyObject *self, PyObject *args, PyObject *kw)
         if (PyList_Insert(list, index, item) < 0)
             return NULL;
     } else {
-        result = PyObject_CallMethod(list, "insert", "iO", index, item);
+        _Py_identifier(insert);
+
+        result = _PyObject_CallMethodId(list, &PyId_insert, "iO", index, item);
         if (result == NULL)
             return NULL;
         Py_DECREF(result);
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 156ad18..40e253d 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -1334,13 +1334,15 @@ defdict_reduce(defdictobject *dd)
     PyObject *items;
     PyObject *iter;
     PyObject *result;
+    _Py_identifier(items);
+
     if (dd->default_factory == NULL || dd->default_factory == Py_None)
         args = PyTuple_New(0);
     else
         args = PyTuple_Pack(1, dd->default_factory);
     if (args == NULL)
         return NULL;
-    items = PyObject_CallMethod((PyObject *)dd, "items", "()");
+    items = _PyObject_CallMethodId((PyObject *)dd, &PyId_items, "()");
     if (items == NULL) {
         Py_DECREF(args);
         return NULL;
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
index e2905bc..1d7cf94 100644
--- a/Modules/_ctypes/_ctypes.c
+++ b/Modules/_ctypes/_ctypes.c
@@ -3679,8 +3679,10 @@ _build_result(PyObject *result, PyObject *callargs,
             PyTuple_SET_ITEM(tup, index, v);
             index++;
         } else if (bit & outmask) {
+            _Py_identifier(__ctypes_from_outparam__);
+
             v = PyTuple_GET_ITEM(callargs, i);
-            v = PyObject_CallMethod(v, "__ctypes_from_outparam__", NULL);
+            v = _PyObject_CallMethodId(v, &PyId___ctypes_from_outparam__, NULL);
             if (v == NULL || numretvals == 1) {
                 Py_DECREF(callargs);
                 return v;
diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 60d59c8..adc2870 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -1687,13 +1687,15 @@ unpickle(PyObject *self, PyObject *args)
     PyObject *state;
     PyObject *result;
     PyObject *tmp;
+    _Py_identifier(__new__);
+    _Py_identifier(__setstate__);
 
     if (!PyArg_ParseTuple(args, "OO", &typ, &state))
         return NULL;
-    result = PyObject_CallMethod(typ, "__new__", "O", typ);
+    result = _PyObject_CallMethodId(typ, &PyId___new__, "O", typ);
     if (result == NULL)
         return NULL;
-    tmp = PyObject_CallMethod(result, "__setstate__", "O", state);
+    tmp = _PyObject_CallMethodId(result, &PyId___setstate__, "O", state);
     if (tmp == NULL) {
         Py_DECREF(result);
         return NULL;
diff --git a/Modules/_cursesmodule.c b/Modules/_cursesmodule.c
index 191d53f..ead38d3 100644
--- a/Modules/_cursesmodule.c
+++ b/Modules/_cursesmodule.c
@@ -1418,10 +1418,12 @@ PyCursesWindow_PutWin(PyCursesWindowObject *self, PyObject *stream)
     while (1) {
         char buf[BUFSIZ];
         Py_ssize_t n = fread(buf, 1, BUFSIZ, fp);
+        _Py_identifier(write);
+
         if (n <= 0)
             break;
         Py_DECREF(res);
-        res = PyObject_CallMethod(stream, "write", "y#", buf, n);
+        res = _PyObject_CallMethodId(stream, &PyId_write, "y#", buf, n);
         if (res == NULL)
             break;
     }
@@ -1911,6 +1913,7 @@ PyCurses_GetWin(PyCursesWindowObject *self, PyObject *stream)
     WINDOW *win;
 
     PyCursesInitialised;
+    _Py_identifier(read);
 
     strcpy(fn, "/tmp/py.curses.getwin.XXXXXX");
     fd = mkstemp(fn);
@@ -1922,7 +1925,7 @@ PyCurses_GetWin(PyCursesWindowObject *self, PyObject *stream)
         remove(fn);
         return PyErr_SetFromErrnoWithFilename(PyExc_IOError, fn);
     }
-    data = PyObject_CallMethod(stream, "read", "");
+    data = _PyObject_CallMethodId(stream, &PyId_read, "");
     if (data == NULL) {
         fclose(fp);
         remove(fn);
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index a7156a4..eb6998f 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -946,6 +946,7 @@ static PyObject *
 call_tzname(PyObject *tzinfo, PyObject *tzinfoarg)
 {
     PyObject *result;
+    _Py_identifier(tzname);
 
     assert(tzinfo != NULL);
     assert(check_tzinfo_subclass(tzinfo) >= 0);
@@ -954,7 +955,7 @@ call_tzname(PyObject *tzinfo, PyObject *tzinfoarg)
     if (tzinfo == Py_None)
         Py_RETURN_NONE;
 
-    result = PyObject_CallMethod(tzinfo, "tzname", "O", tzinfoarg);
+    result = _PyObject_CallMethodId(tzinfo, &PyId_tzname, "O", tzinfoarg);
 
     if (result == NULL || result == Py_None)
         return result;
@@ -1078,6 +1079,8 @@ make_Zreplacement(PyObject *object, PyObject *tzinfoarg)
     PyObject *temp;
     PyObject *tzinfo = get_tzinfo_member(object);
     PyObject *Zreplacement = PyUnicode_FromStringAndSize(NULL, 0);
+    _Py_identifier(replace);
+	
     if (Zreplacement == NULL)
         return NULL;
     if (tzinfo == Py_None || tzinfo == NULL)
@@ -1098,7 +1101,7 @@ make_Zreplacement(PyObject *object, PyObject *tzinfoarg)
      * strftime doesn't treat them as format codes.
      */
     Py_DECREF(Zreplacement);
-    Zreplacement = PyObject_CallMethod(temp, "replace", "ss", "%", "%%");
+    Zreplacement = _PyObject_CallMethodId(temp, &PyId_replace, "ss", "%", "%%");
     Py_DECREF(temp);
     if (Zreplacement == NULL)
         return NULL;
@@ -1281,12 +1284,15 @@ wrap_strftime(PyObject *object, PyObject *format, PyObject *timetuple,
     {
         PyObject *format;
         PyObject *time = PyImport_ImportModuleNoBlock("time");
+
         if (time == NULL)
             goto Done;
         format = PyUnicode_FromString(PyBytes_AS_STRING(newfmt));
         if (format != NULL) {
-            result = PyObject_CallMethod(time, "strftime", "OO",
-                                         format, timetuple, NULL);
+            _Py_identifier(strftime);
+
+            result = _PyObject_CallMethodId(time, &PyId_strftime, "OO",
+                                            format, timetuple, NULL);
             Py_DECREF(format);
         }
         Py_DECREF(time);
@@ -1312,7 +1318,9 @@ time_time(void)
     PyObject *time = PyImport_ImportModuleNoBlock("time");
 
     if (time != NULL) {
-        result = PyObject_CallMethod(time, "time", "()");
+        _Py_identifier(time);
+
+        result = _PyObject_CallMethodId(time, &PyId_time, "()");
         Py_DECREF(time);
     }
     return result;
@@ -1329,13 +1337,15 @@ build_struct_time(int y, int m, int d, int hh, int mm, int ss, int dstflag)
 
     time = PyImport_ImportModuleNoBlock("time");
     if (time != NULL) {
-        result = PyObject_CallMethod(time, "struct_time",
-                                     "((iiiiiiiii))",
-                                     y, m, d,
-                                     hh, mm, ss,
-                                     weekday(y, m, d),
-                                     days_before_month(y, m) + d,
-                                     dstflag);
+        _Py_identifier(struct_time);
+
+        result = _PyObject_CallMethodId(time, &PyId_struct_time,
+                                        "((iiiiiiiii))",
+                                        y, m, d,
+                                        hh, mm, ss,
+                                        weekday(y, m, d),
+                                        days_before_month(y, m) + d,
+                                        dstflag);
         Py_DECREF(time);
     }
     return result;
@@ -1568,11 +1578,12 @@ multiply_float_timedelta(PyObject *floatobj, PyDateTime_Delta *delta)
     PyObject *result = NULL;
     PyObject *pyus_in = NULL, *temp, *pyus_out;
     PyObject *ratio = NULL;
+    _Py_identifier(as_integer_ratio);
 
     pyus_in = delta_to_microseconds(delta);
     if (pyus_in == NULL)
         return NULL;
-    ratio = PyObject_CallMethod(floatobj, "as_integer_ratio", NULL);
+    ratio = _PyObject_CallMethodId(floatobj, &PyId_as_integer_ratio, NULL);
     if (ratio == NULL)
         goto error;
     temp = PyNumber_Multiply(pyus_in, PyTuple_GET_ITEM(ratio, 0));
@@ -1666,11 +1677,12 @@ truedivide_timedelta_float(PyDateTime_Delta *delta, PyObject *f)
     PyObject *result = NULL;
     PyObject *pyus_in = NULL, *temp, *pyus_out;
     PyObject *ratio = NULL;
+    _Py_identifier(as_integer_ratio);
 
     pyus_in = delta_to_microseconds(delta);
     if (pyus_in == NULL)
         return NULL;
-    ratio = PyObject_CallMethod(f, "as_integer_ratio", NULL);
+    ratio = _PyObject_CallMethodId(f, &PyId_as_integer_ratio, NULL);
     if (ratio == NULL)
         goto error;
     temp = PyNumber_Multiply(pyus_in, PyTuple_GET_ITEM(ratio, 1));
@@ -2461,6 +2473,7 @@ date_today(PyObject *cls, PyObject *dummy)
 {
     PyObject *time;
     PyObject *result;
+    _Py_identifier(fromtimestamp);
 
     time = time_time();
     if (time == NULL)
@@ -2472,7 +2485,7 @@ date_today(PyObject *cls, PyObject *dummy)
      * time.time() delivers; if someone were gonzo about optimization,
      * date.today() could get away with plain C time().
      */
-    result = PyObject_CallMethod(cls, "fromtimestamp", "O", time);
+    result = _PyObject_CallMethodId(cls, &PyId_fromtimestamp, "O", time);
     Py_DECREF(time);
     return result;
 }
@@ -2613,7 +2626,9 @@ date_isoformat(PyDateTime_Date *self)
 static PyObject *
 date_str(PyDateTime_Date *self)
 {
-    return PyObject_CallMethod((PyObject *)self, "isoformat", "()");
+    _Py_identifier(isoformat);
+
+    return _PyObject_CallMethodId((PyObject *)self, &PyId_isoformat, "()");
 }
 
 
@@ -2632,13 +2647,14 @@ date_strftime(PyDateTime_Date *self, PyObject *args, PyObject *kw)
     PyObject *result;
     PyObject *tuple;
     PyObject *format;
+    _Py_identifier(timetuple);
     static char *keywords[] = {"format", NULL};
 
     if (! PyArg_ParseTupleAndKeywords(args, kw, "U:strftime", keywords,
                                       &format))
         return NULL;
 
-    tuple = PyObject_CallMethod((PyObject *)self, "timetuple", "()");
+    tuple = _PyObject_CallMethodId((PyObject *)self, &PyId_timetuple, "()");
     if (tuple == NULL)
         return NULL;
     result = wrap_strftime((PyObject *)self, format, tuple,
@@ -2651,6 +2667,7 @@ static PyObject *
 date_format(PyDateTime_Date *self, PyObject *args)
 {
     PyObject *format;
+    _Py_identifier(strftime);
 
     if (!PyArg_ParseTuple(args, "U:__format__", &format))
         return NULL;
@@ -2659,7 +2676,7 @@ date_format(PyDateTime_Date *self, PyObject *args)
     if (PyUnicode_GetSize(format) == 0)
         return PyObject_Str((PyObject *)self);
 
-    return PyObject_CallMethod((PyObject *)self, "strftime", "O", format);
+    return _PyObject_CallMethodId((PyObject *)self, &PyId_strftime, "O", format);
 }
 
 /* ISO methods. */
@@ -3573,7 +3590,9 @@ time_repr(PyDateTime_Time *self)
 static PyObject *
 time_str(PyDateTime_Time *self)
 {
-    return PyObject_CallMethod((PyObject *)self, "isoformat", "()");
+    _Py_identifier(isoformat);
+
+    return _PyObject_CallMethodId((PyObject *)self, &PyId_isoformat, "()");
 }
 
 static PyObject *
@@ -4152,7 +4171,9 @@ datetime_now(PyObject *cls, PyObject *args, PyObject *kw)
     if (self != NULL && tzinfo != Py_None) {
         /* Convert UTC to tzinfo's zone. */
         PyObject *temp = self;
-        self = PyObject_CallMethod(tzinfo, "fromutc", "O", self);
+        _Py_identifier(fromutc);
+
+        self = _PyObject_CallMethodId(tzinfo, &PyId_fromutc, "O", self);
         Py_DECREF(temp);
     }
     return self;
@@ -4189,7 +4210,9 @@ datetime_fromtimestamp(PyObject *cls, PyObject *args, PyObject *kw)
     if (self != NULL && tzinfo != Py_None) {
         /* Convert UTC to tzinfo's zone. */
         PyObject *temp = self;
-        self = PyObject_CallMethod(tzinfo, "fromutc", "O", self);
+        _Py_identifier(fromutc);
+
+        self = _PyObject_CallMethodId(tzinfo, &PyId_fromutc, "O", self);
         Py_DECREF(temp);
     }
     return self;
@@ -4214,6 +4237,7 @@ datetime_strptime(PyObject *cls, PyObject *args)
 {
     static PyObject *module = NULL;
     PyObject *string, *format;
+    _Py_identifier(_strptime_datetime);
 
     if (!PyArg_ParseTuple(args, "UU:strptime", &string, &format))
         return NULL;
@@ -4223,8 +4247,8 @@ datetime_strptime(PyObject *cls, PyObject *args)
         if (module == NULL)
             return NULL;
     }
-    return PyObject_CallMethod(module, "_strptime_datetime", "OOO",
-                               cls, string, format);
+    return _PyObject_CallMethodId(module, &PyId__strptime_datetime, "OOO",
+                                 cls, string, format);
 }
 
 /* Return new datetime from date/datetime and time arguments. */
@@ -4469,7 +4493,9 @@ datetime_repr(PyDateTime_DateTime *self)
 static PyObject *
 datetime_str(PyDateTime_DateTime *self)
 {
-    return PyObject_CallMethod((PyObject *)self, "isoformat", "(s)", " ");
+    _Py_identifier(isoformat);
+
+    return _PyObject_CallMethodId((PyObject *)self, &PyId_isoformat, "(s)", " ");
 }
 
 static PyObject *
@@ -4676,6 +4702,7 @@ datetime_astimezone(PyDateTime_DateTime *self, PyObject *args, PyObject *kw)
     PyObject *offset;
     PyObject *temp;
     PyObject *tzinfo;
+    _Py_identifier(fromutc);
     static char *keywords[] = {"tz", NULL};
 
     if (! PyArg_ParseTupleAndKeywords(args, kw, "O!:astimezone", keywords,
@@ -4717,7 +4744,7 @@ datetime_astimezone(PyDateTime_DateTime *self, PyObject *args, PyObject *kw)
     Py_DECREF(temp);
 
     temp = result;
-    result = PyObject_CallMethod(tzinfo, "fromutc", "O", temp);
+    result = _PyObject_CallMethodId(tzinfo, &PyId_fromutc, "O", temp);
     Py_DECREF(temp);
 
     return result;
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 0c64dd5..fcd1271 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -790,16 +790,18 @@ static PyObject*
 element_find(ElementObject* self, PyObject* args)
 {
     int i;
-
     PyObject* tag;
     PyObject* namespaces = Py_None;
+
     if (!PyArg_ParseTuple(args, "O|O:find", &tag, &namespaces))
         return NULL;
 
-    if (checkpath(tag) || namespaces != Py_None)
-        return PyObject_CallMethod(
-            elementpath_obj, "find", "OOO", self, tag, namespaces
+    if (checkpath(tag) || namespaces != Py_None) {
+        _Py_identifier(find);
+        return _PyObject_CallMethodId(
+            elementpath_obj, &PyId_find, "OOO", self, tag, namespaces
             );
+    }
 
     if (!self->extra)
         Py_RETURN_NONE;
@@ -820,16 +822,17 @@ static PyObject*
 element_findtext(ElementObject* self, PyObject* args)
 {
     int i;
-
     PyObject* tag;
     PyObject* default_value = Py_None;
     PyObject* namespaces = Py_None;
+    _Py_identifier(findtext);
+
     if (!PyArg_ParseTuple(args, "O|OO:findtext", &tag, &default_value, &namespaces))
         return NULL;
 
     if (checkpath(tag) || namespaces != Py_None)
-        return PyObject_CallMethod(
-            elementpath_obj, "findtext", "OOOO", self, tag, default_value, namespaces
+        return _PyObject_CallMethodId(
+            elementpath_obj, &PyId_findtext, "OOOO", self, tag, default_value, namespaces
             );
 
     if (!self->extra) {
@@ -858,16 +861,18 @@ element_findall(ElementObject* self, PyObject* args)
 {
     int i;
     PyObject* out;
-
     PyObject* tag;
     PyObject* namespaces = Py_None;
+
     if (!PyArg_ParseTuple(args, "O|O:findall", &tag, &namespaces))
         return NULL;
 
-    if (checkpath(tag) || namespaces != Py_None)
-        return PyObject_CallMethod(
-            elementpath_obj, "findall", "OOO", self, tag, namespaces
+    if (checkpath(tag) || namespaces != Py_None) {
+        _Py_identifier(findall);
+        return _PyObject_CallMethodId(
+            elementpath_obj, &PyId_findall, "OOO", self, tag, namespaces
             );
+    }
 
     out = PyList_New(0);
     if (!out)
@@ -895,11 +900,13 @@ element_iterfind(ElementObject* self, PyObject* args)
 {
     PyObject* tag;
     PyObject* namespaces = Py_None;
+    _Py_identifier(iterfind);
+
     if (!PyArg_ParseTuple(args, "O|O:iterfind", &tag, &namespaces))
         return NULL;
 
-    return PyObject_CallMethod(
-        elementpath_obj, "iterfind", "OOO", self, tag, namespaces
+    return _PyObject_CallMethodId(
+        elementpath_obj, &PyId_iterfind, "OOO", self, tag, namespaces
         );
 }
 
diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c
index 6f5bd48..f264756 100644
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -308,6 +308,9 @@ io_open(PyObject *self, PyObject *args, PyObject *kwds)
 
     PyObject *raw, *modeobj = NULL, *buffer = NULL, *wrapper = NULL;
 
+    _Py_identifier(isatty);
+    _Py_identifier(fileno);
+
     if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|sizzzi:open", kwlist,
                                      &file, &mode, &buffering,
                                      &encoding, &errors, &newline,
@@ -421,7 +424,7 @@ io_open(PyObject *self, PyObject *args, PyObject *kwds)
 
     /* buffering */
     {
-        PyObject *res = PyObject_CallMethod(raw, "isatty", NULL);
+        PyObject *res = _PyObject_CallMethodId(raw, &PyId_isatty, NULL);
         if (res == NULL)
             goto error;
         isatty = PyLong_AsLong(res);
@@ -443,7 +446,7 @@ io_open(PyObject *self, PyObject *args, PyObject *kwds)
         {
             struct stat st;
             long fileno;
-            PyObject *res = PyObject_CallMethod(raw, "fileno", NULL);
+            PyObject *res = _PyObject_CallMethodId(raw, &PyId_fileno, NULL);
             if (res == NULL)
                 goto error;
 
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index 86f7412..6ef2c20 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -13,6 +13,18 @@
 #include "pythread.h"
 #include "_iomodule.h"
 
+_Py_identifier(close);
+_Py_identifier(_dealloc_warn);
+_Py_identifier(flush);
+_Py_identifier(isatty);
+_Py_identifier(peek);
+_Py_identifier(read);
+_Py_identifier(read1);
+_Py_identifier(readable);
+_Py_identifier(readinto);
+_Py_identifier(writable);
+_Py_identifier(write);
+
 /*
  * BufferedIOBase class, inherits from IOBase.
  */
@@ -38,12 +50,13 @@ bufferediobase_readinto(PyObject *self, PyObject *args)
     Py_buffer buf;
     Py_ssize_t len;
     PyObject *data;
+    _Py_identifier(read);
 
     if (!PyArg_ParseTuple(args, "w*:readinto", &buf)) {
         return NULL;
     }
 
-    data = PyObject_CallMethod(self, "read", "n", buf.len);
+    data = _PyObject_CallMethodId(self, &PyId_read, "n", buf.len);
     if (data == NULL)
         goto error;
 
@@ -410,7 +423,7 @@ buffered_dealloc_warn(buffered *self, PyObject *source)
 {
     if (self->ok && self->raw) {
         PyObject *r;
-        r = PyObject_CallMethod(self->raw, "_dealloc_warn", "O", source);
+        r = _PyObject_CallMethodId(self->raw, &PyId__dealloc_warn, "O", source);
         if (r)
             Py_DECREF(r);
         else
@@ -2216,13 +2229,13 @@ bufferedrwpair_dealloc(rwpair *self)
 }
 
 static PyObject *
-_forward_call(buffered *self, const char *name, PyObject *args)
+_forward_call(buffered *self, _Py_Identifier *name, PyObject *args)
 {
-    PyObject *func = PyObject_GetAttrString((PyObject *)self, name);
+    PyObject *func = _PyObject_GetAttrId((PyObject *)self, name);
     PyObject *ret;
 
     if (func == NULL) {
-        PyErr_SetString(PyExc_AttributeError, name);
+        PyErr_SetString(PyExc_AttributeError, name->string);
         return NULL;
     }
 
@@ -2234,66 +2247,66 @@ _forward_call(buffered *self, const char *name, PyObject *args)
 static PyObject *
 bufferedrwpair_read(rwpair *self, PyObject *args)
 {
-    return _forward_call(self->reader, "read", args);
+    return _forward_call(self->reader, &PyId_read, args);
 }
 
 static PyObject *
 bufferedrwpair_peek(rwpair *self, PyObject *args)
 {
-    return _forward_call(self->reader, "peek", args);
+    return _forward_call(self->reader, &PyId_peek, args);
 }
 
 static PyObject *
 bufferedrwpair_read1(rwpair *self, PyObject *args)
 {
-    return _forward_call(self->reader, "read1", args);
+    return _forward_call(self->reader, &PyId_read1, args);
 }
 
 static PyObject *
 bufferedrwpair_readinto(rwpair *self, PyObject *args)
 {
-    return _forward_call(self->reader, "readinto", args);
+    return _forward_call(self->reader, &PyId_readinto, args);
 }
 
 static PyObject *
 bufferedrwpair_write(rwpair *self, PyObject *args)
 {
-    return _forward_call(self->writer, "write", args);
+    return _forward_call(self->writer, &PyId_write, args);
 }
 
 static PyObject *
 bufferedrwpair_flush(rwpair *self, PyObject *args)
 {
-    return _forward_call(self->writer, "flush", args);
+    return _forward_call(self->writer, &PyId_flush, args);
 }
 
 static PyObject *
 bufferedrwpair_readable(rwpair *self, PyObject *args)
 {
-    return _forward_call(self->reader, "readable", args);
+    return _forward_call(self->reader, &PyId_readable, args);
 }
 
 static PyObject *
 bufferedrwpair_writable(rwpair *self, PyObject *args)
 {
-    return _forward_call(self->writer, "writable", args);
+    return _forward_call(self->writer, &PyId_writable, args);
 }
 
 static PyObject *
 bufferedrwpair_close(rwpair *self, PyObject *args)
 {
-    PyObject *ret = _forward_call(self->writer, "close", args);
+    PyObject *ret = _forward_call(self->writer, &PyId_close, args);
     if (ret == NULL)
         return NULL;
     Py_DECREF(ret);
 
-    return _forward_call(self->reader, "close", args);
+    return _forward_call(self->reader, &PyId_close, args);
 }
 
 static PyObject *
 bufferedrwpair_isatty(rwpair *self, PyObject *args)
 {
-    PyObject *ret = _forward_call(self->writer, "isatty", args);
+    PyObject *ret = _forward_call(self->writer, &PyId_isatty, args);
 
     if (ret != Py_False) {
         /* either True or exception */
@@ -2301,7 +2314,7 @@ bufferedrwpair_isatty(rwpair *self, PyObject *args)
     }
     Py_DECREF(ret);
 
-    return _forward_call(self->reader, "isatty", args);
+    return _forward_call(self->reader, &PyId_isatty, args);
 }
 
 static PyObject *
diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index 2bf8933..a16d13c 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -128,6 +128,7 @@ internal_close(fileio *self)
 static PyObject *
 fileio_close(fileio *self)
 {
+    _Py_identifier(close);
     if (!self->closefd) {
         self->fd = -1;
         Py_RETURN_NONE;
@@ -143,8 +144,8 @@ fileio_close(fileio *self)
     if (errno < 0)
         return NULL;
 
-    return PyObject_CallMethod((PyObject*)&PyRawIOBase_Type,
-                               "close", "O", self);
+    return _PyObject_CallMethodId((PyObject*)&PyRawIOBase_Type,
+                                  &PyId_close, "O", self);
 }
 
 static PyObject *
diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c
index 35c7cdd..6a94a04 100644
--- a/Modules/_io/iobase.c
+++ b/Modules/_io/iobase.c
@@ -97,7 +97,9 @@ PyDoc_STRVAR(iobase_tell_doc,
 static PyObject *
 iobase_tell(PyObject *self, PyObject *args)
 {
-    return PyObject_CallMethod(self, "seek", "ii", 0, 1);
+    _Py_identifier(seek);
+
+    return _PyObject_CallMethodId(self, &PyId_seek, "ii", 0, 1);
 }
 
 PyDoc_STRVAR(iobase_truncate_doc,
@@ -464,6 +466,7 @@ iobase_readline(PyObject *self, PyObject *args)
     int has_peek = 0;
     PyObject *buffer, *result;
     Py_ssize_t old_size = -1;
+    _Py_identifier(read);
 
     if (!PyArg_ParseTuple(args, "|O&:readline", &_PyIO_ConvertSsize_t, &limit)) {
         return NULL;
@@ -481,7 +484,9 @@ iobase_readline(PyObject *self, PyObject *args)
         PyObject *b;
 
         if (has_peek) {
-            PyObject *readahead = PyObject_CallMethod(self, "peek", "i", 1);
+            _Py_identifier(peek);
+            PyObject *readahead = _PyObject_CallMethodId(self, &PyId_peek, "i", 1);
+
             if (readahead == NULL)
                 goto fail;
             if (!PyBytes_Check(readahead)) {
@@ -515,7 +520,7 @@ iobase_readline(PyObject *self, PyObject *args)
             Py_DECREF(readahead);
         }
 
-        b = PyObject_CallMethod(self, "read", "n", nreadahead);
+        b = _PyObject_CallMethodId(self, &PyId_read, "n", nreadahead);
         if (b == NULL)
             goto fail;
         if (!PyBytes_Check(b)) {
@@ -601,7 +606,9 @@ iobase_readlines(PyObject *self, PyObject *args)
         /* XXX special-casing this made sense in the Python version in order
            to remove the bytecode interpretation overhead, but it could
            probably be removed here. */
-        PyObject *ret = PyObject_CallMethod(result, "extend", "O", self);
+        _Py_identifier(extend);
+        PyObject *ret = _PyObject_CallMethodId(result, &PyId_extend, "O", self);
+
         if (ret == NULL) {
             Py_DECREF(result);
             return NULL;
@@ -781,8 +788,11 @@ rawiobase_read(PyObject *self, PyObject *args)
         return NULL;
     }
 
-    if (n < 0)
-        return PyObject_CallMethod(self, "readall", NULL);
+    if (n < 0) {
+        _Py_identifier(readall);
+
+        return _PyObject_CallMethodId(self, &PyId_readall, NULL);
+    }
 
     /* TODO: allocate a bytes object directly instead and manually construct
        a writable memoryview pointing to it. */
@@ -823,8 +833,9 @@ rawiobase_readall(PyObject *self, PyObject *args)
         return NULL;
 
     while (1) {
-        PyObject *data = PyObject_CallMethod(self, "read",
-                                             "i", DEFAULT_BUFFER_SIZE);
+        _Py_identifier(read);
+        PyObject *data = _PyObject_CallMethodId(self, &PyId_read,
+                                                "i", DEFAULT_BUFFER_SIZE);
         if (!data) {
             Py_DECREF(chunks);
             return NULL;
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index aa29ffb..2ded719 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -11,6 +11,24 @@
 #include "structmember.h"
 #include "_iomodule.h"
 
+_Py_identifier(close);
+_Py_identifier(_dealloc_warn);
+_Py_identifier(decode);
+_Py_identifier(device_encoding);
+_Py_identifier(fileno);
+_Py_identifier(flush);
+_Py_identifier(getpreferredencoding);
+_Py_identifier(isatty);
+_Py_identifier(read);
+_Py_identifier(readable);
+_Py_identifier(replace);
+_Py_identifier(reset);
+_Py_identifier(seek);
+_Py_identifier(seekable);
+_Py_identifier(setstate);
+_Py_identifier(tell);
+_Py_identifier(writable);
+
 /* TextIOBase */
 
 PyDoc_STRVAR(textiobase_doc,
@@ -501,8 +519,8 @@ incrementalnewlinedecoder_setstate(nldecoder_object *self, PyObject *state)
     flag >>= 1;
 
     if (self->decoder != Py_None)
-        return PyObject_CallMethod(self->decoder,
-                                   "setstate", "((OK))", buffer, flag);
+        return _PyObject_CallMethodId(self->decoder,
+                                      &PyId_setstate, "((OK))", buffer, flag);
     else
         Py_RETURN_NONE;
 }
@@ -842,7 +860,7 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
     if (encoding == NULL) {
         /* Try os.device_encoding(fileno) */
         PyObject *fileno;
-        fileno = PyObject_CallMethod(buffer, "fileno", NULL);
+        fileno = _PyObject_CallMethodId(buffer, &PyId_fileno, NULL);
         /* Ignore only AttributeError and UnsupportedOperation */
         if (fileno == NULL) {
             if (PyErr_ExceptionMatches(PyExc_AttributeError) ||
@@ -854,9 +872,9 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
             }
         }
         else {
-            self->encoding = PyObject_CallMethod(state->os_module,
-                                                 "device_encoding",
-                                                 "N", fileno);
+            self->encoding = _PyObject_CallMethodId(state->os_module,
+                                                    &PyId_device_encoding,
+                                                    "N", fileno);
             if (self->encoding == NULL)
                 goto error;
             else if (!PyUnicode_Check(self->encoding))
@@ -873,8 +891,8 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
         }
         else {
           use_locale:
-            self->encoding = PyObject_CallMethod(
-                state->locale_module, "getpreferredencoding", NULL);
+            self->encoding = _PyObject_CallMethodId(
+                state->locale_module, &PyId_getpreferredencoding, NULL);
             if (self->encoding == NULL) {
               catch_ImportError:
                 /*
@@ -939,7 +957,7 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
 #endif
 
     /* Build the decoder object */
-    res = PyObject_CallMethod(buffer, "readable", NULL);
+    res = _PyObject_CallMethodId(buffer, &PyId_readable, NULL);
     if (res == NULL)
         goto error;
     r = PyObject_IsTrue(res);
@@ -964,7 +982,7 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
     }
 
     /* Build the encoder object */
-    res = PyObject_CallMethod(buffer, "writable", NULL);
+    res = _PyObject_CallMethodId(buffer, &PyId_writable, NULL);
     if (res == NULL)
         goto error;
     r = PyObject_IsTrue(res);
@@ -1022,7 +1040,7 @@ textiowrapper_init(textio *self, PyObject *args, PyObject *kwds)
             Py_DECREF(raw);
     }
 
-    res = PyObject_CallMethod(buffer, "seekable", NULL);
+    res = _PyObject_CallMethodId(buffer, &PyId_seekable, NULL);
     if (res == NULL)
         goto error;
     self->seekable = self->telling = PyObject_IsTrue(res);
@@ -1255,8 +1273,8 @@ textiowrapper_write(textio *self, PyObject *args)
             haslf = 1;
 
     if (haslf && self->writetranslate && self->writenl != NULL) {
-        PyObject *newtext = PyObject_CallMethod(
-            text, "replace", "ss", "\n", self->writenl);
+        PyObject *newtext = _PyObject_CallMethodId(
+            text, &PyId_replace, "ss", "\n", self->writenl);
         Py_DECREF(text);
         if (newtext == NULL)
             return NULL;
@@ -1311,7 +1329,7 @@ textiowrapper_write(textio *self, PyObject *args)
     Py_CLEAR(self->snapshot);
 
     if (self->decoder) {
-        ret = PyObject_CallMethod(self->decoder, "reset", NULL);
+        ret = _PyObject_CallMethodId(self->decoder, &PyId_reset, NULL);
         if (ret == NULL)
             return NULL;
         Py_DECREF(ret);
@@ -1490,7 +1508,7 @@ textiowrapper_read(textio *self, PyObject *args)
 
     if (n < 0) {
         /* Read everything */
-        PyObject *bytes = PyObject_CallMethod(self->buffer, "read", NULL);
+        PyObject *bytes = _PyObject_CallMethodId(self->buffer, &PyId_read, NULL);
         PyObject *decoded;
         if (bytes == NULL)
             goto fail;
@@ -1940,8 +1958,8 @@ _textiowrapper_decoder_setstate(textio *self, cookie_type *cookie)
     if (cookie->start_pos == 0 && cookie->dec_flags == 0)
         res = PyObject_CallMethodObjArgs(self->decoder, _PyIO_str_reset, NULL);
     else
-        res = PyObject_CallMethod(self->decoder, "setstate",
-                                  "((yi))", "", cookie->dec_flags);
+        res = _PyObject_CallMethodId(self->decoder, &PyId_setstate,
+                                     "((yi))", "", cookie->dec_flags);
     if (res == NULL)
         return -1;
     Py_DECREF(res);
@@ -2005,13 +2023,12 @@ textiowrapper_seek(textio *self, PyObject *args)
          * sync the underlying buffer with the current position.
          */
         Py_DECREF(cookieObj);
-        cookieObj = PyObject_CallMethod((PyObject *)self, "tell", NULL);
+        cookieObj = _PyObject_CallMethodId((PyObject *)self, &PyId_tell, NULL);
         if (cookieObj == NULL)
             goto fail;
     }
     else if (whence == 2) {
         /* seek relative to end of file */
-
         cmp = PyObject_RichCompareBool(cookieObj, _PyIO_zero, Py_EQ);
         if (cmp < 0)
             goto fail;
@@ -2021,7 +2038,7 @@ textiowrapper_seek(textio *self, PyObject *args)
             goto fail;
         }
 
-        res = PyObject_CallMethod((PyObject *)self, "flush", NULL);
+        res = _PyObject_CallMethodId((PyObject *)self, &PyId_flush, NULL);
         if (res == NULL)
             goto fail;
         Py_DECREF(res);
@@ -2029,13 +2046,13 @@ textiowrapper_seek(textio *self, PyObject *args)
         textiowrapper_set_decoded_chars(self, NULL);
         Py_CLEAR(self->snapshot);
         if (self->decoder) {
-            res = PyObject_CallMethod(self->decoder, "reset", NULL);
+            res = _PyObject_CallMethodId(self->decoder, &PyId_reset, NULL);
             if (res == NULL)
                 goto fail;
             Py_DECREF(res);
         }
 
-        res = PyObject_CallMethod(self->buffer, "seek", "ii", 0, 2);
+        res = _PyObject_CallMethodId(self->buffer, &PyId_seek, "ii", 0, 2);
         Py_XDECREF(cookieObj);
         return res;
     }
@@ -2088,8 +2105,8 @@ textiowrapper_seek(textio *self, PyObject *args)
 
     if (cookie.chars_to_skip) {
         /* Just like _read_chunk, feed the decoder and save a snapshot. */
-        PyObject *input_chunk = PyObject_CallMethod(
-            self->buffer, "read", "i", cookie.bytes_to_feed);
+        PyObject *input_chunk = _PyObject_CallMethodId(
+            self->buffer, &PyId_read, "i", cookie.bytes_to_feed);
         PyObject *decoded;
 
         if (input_chunk == NULL)
@@ -2103,8 +2120,8 @@ textiowrapper_seek(textio *self, PyObject *args)
             goto fail;
         }
 
-        decoded = PyObject_CallMethod(self->decoder, "decode",
-                                      "Oi", input_chunk, (int)cookie.need_eof);
+        decoded = _PyObject_CallMethodId(self->decoder, &PyId_decode,
+            "Oi", input_chunk, (int)cookie.need_eof);
 
         if (decoded == NULL)
             goto fail;
@@ -2170,12 +2187,12 @@ textiowrapper_tell(textio *self, PyObject *args)
 
     if (_textiowrapper_writeflush(self) < 0)
         return NULL;
-    res = PyObject_CallMethod((PyObject *)self, "flush", NULL);
+    res = _PyObject_CallMethodId((PyObject *)self, &PyId_flush, NULL);
     if (res == NULL)
         goto fail;
     Py_DECREF(res);
 
-    posobj = PyObject_CallMethod(self->buffer, "tell", NULL);
+    posobj = _PyObject_CallMethodId(self->buffer, &PyId_tell, NULL);
     if (posobj == NULL)
         goto fail;
 
@@ -2229,8 +2246,8 @@ textiowrapper_tell(textio *self, PyObject *args)
 
     /* TODO: replace assert with exception */
 #define DECODER_DECODE(start, len, res) do { \
-        PyObject *_decoded = PyObject_CallMethod( \
-            self->decoder, "decode", "y#", start, len); \
+        PyObject *_decoded = _PyObject_CallMethodId( \
+            self->decoder, &PyId_decode, "y#", start, len); \
         if (_decoded == NULL) \
             goto fail; \
         assert (PyUnicode_Check(_decoded)); \
@@ -2312,8 +2329,8 @@ textiowrapper_tell(textio *self, PyObject *args)
     }
     if (input == input_end) {
         /* We didn't get enough decoded data; signal EOF to get more. */
-        PyObject *decoded = PyObject_CallMethod(
-            self->decoder, "decode", "yi", "", /* final = */ 1);
+        PyObject *decoded = _PyObject_CallMethodId(
+            self->decoder, &PyId_decode, "yi", "", /* final = */ 1);
         if (decoded == NULL)
             goto fail;
         assert (PyUnicode_Check(decoded));
@@ -2329,7 +2346,7 @@ textiowrapper_tell(textio *self, PyObject *args)
     }
 
 finally:
-    res = PyObject_CallMethod(self->decoder, "setstate", "(O)", saved_state);
+    res = _PyObject_CallMethodId(self->decoder, &PyId_setstate, "(O)", saved_state);
     Py_DECREF(saved_state);
     if (res == NULL)
         return NULL;
@@ -2344,7 +2361,7 @@ fail:
         PyObject *type, *value, *traceback;
         PyErr_Fetch(&type, &value, &traceback);
 
-        res = PyObject_CallMethod(self->decoder, "setstate", "(O)", saved_state);
+        res = _PyObject_CallMethodId(self->decoder, &PyId_setstate, "(O)", saved_state);
         Py_DECREF(saved_state);
         if (res == NULL)
             return NULL;
@@ -2432,35 +2449,35 @@ static PyObject *
 textiowrapper_fileno(textio *self, PyObject *args)
 {
     CHECK_INITIALIZED(self);
-    return PyObject_CallMethod(self->buffer, "fileno", NULL);
+    return _PyObject_CallMethodId(self->buffer, &PyId_fileno, NULL);
 }
 
 static PyObject *
 textiowrapper_seekable(textio *self, PyObject *args)
 {
     CHECK_INITIALIZED(self);
-    return PyObject_CallMethod(self->buffer, "seekable", NULL);
+    return _PyObject_CallMethodId(self->buffer, &PyId_seekable, NULL);
 }
 
 static PyObject *
 textiowrapper_readable(textio *self, PyObject *args)
 {
     CHECK_INITIALIZED(self);
-    return PyObject_CallMethod(self->buffer, "readable", NULL);
+    return _PyObject_CallMethodId(self->buffer, &PyId_readable, NULL);
 }
 
 static PyObject *
 textiowrapper_writable(textio *self, PyObject *args)
 {
     CHECK_INITIALIZED(self);
-    return PyObject_CallMethod(self->buffer, "writable", NULL);
+    return _PyObject_CallMethodId(self->buffer, &PyId_writable, NULL);
 }
 
 static PyObject *
 textiowrapper_isatty(textio *self, PyObject *args)
 {
     CHECK_INITIALIZED(self);
-    return PyObject_CallMethod(self->buffer, "isatty", NULL);
+    return _PyObject_CallMethodId(self->buffer, &PyId_isatty, NULL);
 }
 
 static PyObject *
@@ -2479,7 +2496,7 @@ textiowrapper_flush(textio *self, PyObject *args)
     self->telling = self->seekable;
     if (_textiowrapper_writeflush(self) < 0)
         return NULL;
-    return PyObject_CallMethod(self->buffer, "flush", NULL);
+    return _PyObject_CallMethodId(self->buffer, &PyId_flush, NULL);
 }
 
 static PyObject *
@@ -2502,20 +2519,20 @@ textiowrapper_close(textio *self, PyObject *args)
     }
     else {
         if (self->deallocating) {
-            res = PyObject_CallMethod(self->buffer, "_dealloc_warn", "O", self);
+            res = _PyObject_CallMethodId(self->buffer, &PyId__dealloc_warn, "O", self);
             if (res)
                 Py_DECREF(res);
             else
                 PyErr_Clear();
         }
-        res = PyObject_CallMethod((PyObject *)self, "flush", NULL);
+        res = _PyObject_CallMethodId((PyObject *)self, &PyId_flush, NULL);
         if (res == NULL) {
             return NULL;
         }
         else
             Py_DECREF(res);
 
-        return PyObject_CallMethod(self->buffer, "close", NULL);
+        return _PyObject_CallMethodId(self->buffer, &PyId_close, NULL);
     }
 }
 
diff --git a/Modules/_pickle.c b/Modules/_pickle.c
index 0b10009..e53abc88 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -2488,7 +2488,9 @@ save_dict(PicklerObject *self, PyObject *obj)
             status = batch_dict_exact(self, obj);
             Py_LeaveRecursiveCall();
         } else {
-            items = PyObject_CallMethod(obj, "items", "()");
+            _Py_identifier(items);
+
+            items = _PyObject_CallMethodId(obj, &PyId_items, "()");
             if (items == NULL)
                 goto error;
             iter = PyObject_GetIter(items);
@@ -3774,8 +3776,10 @@ static PyTypeObject Pickler_Type = {
 static PyObject *
 find_class(UnpicklerObject *self, PyObject *module_name, PyObject *global_name)
 {
-    return PyObject_CallMethod((PyObject *)self, "find_class", "OO",
-                               module_name, global_name);
+    _Py_identifier(find_class);
+
+    return _PyObject_CallMethodId((PyObject *)self, &PyId_find_class, "OO",
+                                  module_name, global_name);
 }
 
 static Py_ssize_t
@@ -4388,7 +4392,9 @@ instantiate(PyObject *cls, PyObject *args)
         result = PyObject_CallObject(cls, args);
     }
     else {
-        result = PyObject_CallMethod(cls, "__new__", "O", cls);
+        _Py_identifier(__new__);
+
+        result = _PyObject_CallMethodId(cls, &PyId___new__, "O", cls);
     }
     return result;
 }
diff --git a/Modules/_posixsubprocess.c b/Modules/_posixsubprocess.c
index bc2f72c..e6a9283 100644
--- a/Modules/_posixsubprocess.c
+++ b/Modules/_posixsubprocess.c
@@ -18,7 +18,9 @@ static long max_fd;
 static int _enable_gc(PyObject *gc_module)
 {
     PyObject *result;
-    result = PyObject_CallMethod(gc_module, "enable", NULL);
+    _Py_identifier(enable);
+
+    result = _PyObject_CallMethodId(gc_module, &PyId_enable, NULL);
     if (result == NULL)
         return 1;
     Py_DECREF(result);
@@ -249,10 +251,13 @@ subprocess_fork_exec(PyObject* self, PyObject *args)
     /* We need to call gc.disable() when we'll be calling preexec_fn */
     if (preexec_fn != Py_None) {
         PyObject *result;
+        _Py_identifier(isenabled);
+        _Py_identifier(disable);
+        
         gc_module = PyImport_ImportModule("gc");
         if (gc_module == NULL)
             return NULL;
-        result = PyObject_CallMethod(gc_module, "isenabled", NULL);
+        result = _PyObject_CallMethodId(gc_module, &PyId_isenabled, NULL);
         if (result == NULL) {
             Py_DECREF(gc_module);
             return NULL;
@@ -263,7 +268,7 @@ subprocess_fork_exec(PyObject* self, PyObject *args)
             Py_DECREF(gc_module);
             return NULL;
         }
-        result = PyObject_CallMethod(gc_module, "disable", NULL);
+        result = _PyObject_CallMethodId(gc_module, &PyId_disable, NULL);
         if (result == NULL) {
             Py_DECREF(gc_module);
             return NULL;
diff --git a/Modules/_sqlite/connection.c b/Modules/_sqlite/connection.c
index 310a27c..c2f218f 100644
--- a/Modules/_sqlite/connection.c
+++ b/Modules/_sqlite/connection.c
@@ -675,6 +675,7 @@ void _pysqlite_final_callback(sqlite3_context* context)
 {
     PyObject* function_result = NULL;
     PyObject** aggregate_instance;
+    _Py_identifier(finalize);
 
 #ifdef WITH_THREAD
     PyGILState_STATE threadstate;
@@ -690,7 +691,7 @@ void _pysqlite_final_callback(sqlite3_context* context)
         goto error;
     }
 
-    function_result = PyObject_CallMethod(*aggregate_instance, "finalize", "");
+    function_result = _PyObject_CallMethodId(*aggregate_instance, &PyId_finalize, "");
     if (!function_result) {
         if (_enable_callback_tracebacks) {
             PyErr_Print();
@@ -1230,8 +1231,9 @@ PyObject* pysqlite_connection_execute(pysqlite_Connection* self, PyObject* args,
     PyObject* cursor = 0;
     PyObject* result = 0;
     PyObject* method = 0;
+    _Py_identifier(cursor);
 
-    cursor = PyObject_CallMethod((PyObject*)self, "cursor", "");
+    cursor = _PyObject_CallMethodId((PyObject*)self, &PyId_cursor, "");
     if (!cursor) {
         goto error;
     }
@@ -1259,8 +1261,9 @@ PyObject* pysqlite_connection_executemany(pysqlite_Connection* self, PyObject* a
     PyObject* cursor = 0;
     PyObject* result = 0;
     PyObject* method = 0;
+    _Py_identifier(cursor);
 
-    cursor = PyObject_CallMethod((PyObject*)self, "cursor", "");
+    cursor = _PyObject_CallMethodId((PyObject*)self, &PyId_cursor, "");
     if (!cursor) {
         goto error;
     }
@@ -1288,8 +1291,9 @@ PyObject* pysqlite_connection_executescript(pysqlite_Connection* self, PyObject*
     PyObject* cursor = 0;
     PyObject* result = 0;
     PyObject* method = 0;
+    _Py_identifier(cursor);
 
-    cursor = PyObject_CallMethod((PyObject*)self, "cursor", "");
+    cursor = _PyObject_CallMethodId((PyObject*)self, &PyId_cursor, "");
     if (!cursor) {
         goto error;
     }
@@ -1437,6 +1441,7 @@ pysqlite_connection_create_collation(pysqlite_Connection* self, PyObject* args)
     PyObject* name;
     PyObject* retval;
     Py_ssize_t i, len;
+    _Py_identifier(upper);
     char *uppercase_name_str;
     int rc;
     unsigned int kind;
@@ -1450,7 +1455,7 @@ pysqlite_connection_create_collation(pysqlite_Connection* self, PyObject* args)
         goto finally;
     }
 
-    uppercase_name = PyObject_CallMethod(name, "upper", "");
+    uppercase_name = _PyObject_CallMethodId(name, &PyId_upper, "");
     if (!uppercase_name) {
         goto finally;
     }
diff --git a/Modules/_sqlite/cursor.c b/Modules/_sqlite/cursor.c
index 264ae45..b47fed4 100644
--- a/Modules/_sqlite/cursor.c
+++ b/Modules/_sqlite/cursor.c
@@ -150,8 +150,9 @@ PyObject* _pysqlite_get_converter(PyObject* key)
 {
     PyObject* upcase_key;
     PyObject* retval;
+    _Py_identifier(upper);
 
-    upcase_key = PyObject_CallMethod(key, "upper", "");
+    upcase_key = _PyObject_CallMethodId(key, &PyId_upper, "");
     if (!upcase_key) {
         return NULL;
     }
diff --git a/Modules/_sqlite/microprotocols.c b/Modules/_sqlite/microprotocols.c
index c730afa..c0f5e22 100644
--- a/Modules/_sqlite/microprotocols.c
+++ b/Modules/_sqlite/microprotocols.c
@@ -95,7 +95,9 @@ pysqlite_microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
 
     /* try to have the protocol adapt this object*/
     if (PyObject_HasAttrString(proto, "__adapt__")) {
-        PyObject *adapted = PyObject_CallMethod(proto, "__adapt__", "O", obj);
+        _Py_identifier(__adapt__);
+        PyObject *adapted = _PyObject_CallMethodId(proto, &PyId___adapt__, "O", obj);
+
         if (adapted) {
             if (adapted != Py_None) {
                 return adapted;
@@ -110,7 +112,9 @@ pysqlite_microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
 
     /* and finally try to have the object adapt itself */
     if (PyObject_HasAttrString(obj, "__conform__")) {
-        PyObject *adapted = PyObject_CallMethod(obj, "__conform__","O", proto);
+        _Py_identifier(__conform__);
+        PyObject *adapted = _PyObject_CallMethodId(obj, &PyId___conform__,"O", proto);
+
         if (adapted) {
             if (adapted != Py_None) {
                 return adapted;
diff --git a/Modules/_sqlite/module.c b/Modules/_sqlite/module.c
index cbc3b8e..20e1ec7 100644
--- a/Modules/_sqlite/module.c
+++ b/Modules/_sqlite/module.c
@@ -179,13 +179,14 @@ static PyObject* module_register_converter(PyObject* self, PyObject* args)
     PyObject* name = NULL;
     PyObject* callable;
     PyObject* retval = NULL;
+    _Py_identifier(upper);
 
     if (!PyArg_ParseTuple(args, "UO", &orig_name, &callable)) {
         return NULL;
     }
 
     /* convert the name to upper case */
-    name = PyObject_CallMethod(orig_name, "upper", "");
+    name = _PyObject_CallMethodId(orig_name, &PyId_upper, "");
     if (!name) {
         goto error;
     }
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index 0032594..6cedee4 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -1253,6 +1253,7 @@ array_fromfile(arrayobject *self, PyObject *args)
     PyObject *f, *b, *res;
     Py_ssize_t itemsize = self->ob_descr->itemsize;
     Py_ssize_t n, nbytes;
+    _Py_identifier(read);
     int not_enough_bytes;
 
     if (!PyArg_ParseTuple(args, "On:fromfile", &f, &n))
@@ -1264,7 +1265,7 @@ array_fromfile(arrayobject *self, PyObject *args)
         return NULL;
     }
 
-    b = PyObject_CallMethod(f, "read", "n", nbytes);
+    b = _PyObject_CallMethodId(f, &PyId_read, "n", nbytes);
     if (b == NULL)
         return NULL;
 
@@ -1321,12 +1322,14 @@ array_tofile(arrayobject *self, PyObject *f)
         char* ptr = self->ob_item + i*BLOCKSIZE;
         Py_ssize_t size = BLOCKSIZE;
         PyObject *bytes, *res;
+        _Py_identifier(write);
+
         if (i*BLOCKSIZE + size > nbytes)
             size = nbytes - i*BLOCKSIZE;
         bytes = PyBytes_FromStringAndSize(ptr, size);
         if (bytes == NULL)
             return NULL;
-        res = PyObject_CallMethod(f, "write", "O", bytes);
+        res = _PyObject_CallMethodId(f, &PyId_write, "O", bytes);
         Py_DECREF(bytes);
         if (res == NULL)
             return NULL;
diff --git a/Modules/cjkcodecs/multibytecodec.c b/Modules/cjkcodecs/multibytecodec.c
index 1b37845..8635a56 100644
--- a/Modules/cjkcodecs/multibytecodec.c
+++ b/Modules/cjkcodecs/multibytecodec.c
@@ -1579,12 +1579,13 @@ mbstreamwriter_iwrite(MultibyteStreamWriterObject *self,
                       PyObject *unistr)
 {
     PyObject *str, *wr;
+    _Py_identifier(write);
 
     str = encoder_encode_stateful(STATEFUL_ECTX(self), unistr, 0);
     if (str == NULL)
         return -1;
 
-    wr = PyObject_CallMethod(self->stream, "write", "O", str);
+    wr = _PyObject_CallMethodId(self->stream, &PyId_write, "O", str);
     Py_DECREF(str);
     if (wr == NULL)
         return -1;
@@ -1650,7 +1651,9 @@ mbstreamwriter_reset(MultibyteStreamWriterObject *self)
     assert(PyBytes_Check(pwrt));
     if (PyBytes_Size(pwrt) > 0) {
         PyObject *wr;
-        wr = PyObject_CallMethod(self->stream, "write", "O", pwrt);
+        _Py_identifier(write);
+
+        wr = _PyObject_CallMethodId(self->stream, &PyId_write, "O", pwrt);
         if (wr == NULL) {
             Py_DECREF(pwrt);
             return NULL;
diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c
index 06f7f2e..11d5340 100644
--- a/Modules/faulthandler.c
+++ b/Modules/faulthandler.c
@@ -146,6 +146,8 @@ static PyObject*
 faulthandler_get_fileno(PyObject *file, int *p_fd)
 {
     PyObject *result;
+    _Py_identifier(fileno);
+    _Py_identifier(flush);
     long fd_long;
     int fd;
 
@@ -157,7 +159,7 @@ faulthandler_get_fileno(PyObject *file, int *p_fd)
         }
     }
 
-    result = PyObject_CallMethod(file, "fileno", "");
+    result = _PyObject_CallMethodId(file, &PyId_fileno, "");
     if (result == NULL)
         return NULL;
 
@@ -175,7 +177,7 @@ faulthandler_get_fileno(PyObject *file, int *p_fd)
         return NULL;
     }
 
-    result = PyObject_CallMethod(file, "flush", "");
+    result = _PyObject_CallMethodId(file, &PyId_flush, "");
     if (result != NULL)
         Py_DECREF(result);
     else {
@@ -1197,6 +1199,7 @@ static int
 faulthandler_env_options(void)
 {
     PyObject *xoptions, *key, *module, *res;
+    _Py_identifier(enable);
 
     if (!Py_GETENV("PYTHONFAULTHANDLER")) {
         int has_key;
@@ -1219,7 +1222,7 @@ faulthandler_env_options(void)
     if (module == NULL) {
         return -1;
     }
-    res = PyObject_CallMethod(module, "enable", "");
+    res = _PyObject_CallMethodId(module, &PyId_enable, "");
     Py_DECREF(module);
     if (res == NULL)
         return -1;
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index b05675c..2533de6 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -769,7 +769,9 @@ get_time(void)
 {
     double result = 0;
     if (tmod != NULL) {
-        PyObject *f = PyObject_CallMethod(tmod, "time", NULL);
+        _Py_identifier(time);
+
+        PyObject *f = _PyObject_CallMethodId(tmod, &PyId_time, NULL);
         if (f == NULL) {
             PyErr_Clear();
         }
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index d0897c3..4f81fe2 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -654,7 +654,9 @@ tee(PyObject *self, PyObject *args)
         copyable = it;
     PyTuple_SET_ITEM(result, 0, copyable);
     for (i=1 ; i<n ; i++) {
-        copyable = PyObject_CallMethod(copyable, "__copy__", NULL);
+        _Py_identifier(__copy__);
+
+        copyable = _PyObject_CallMethodId(copyable, &PyId___copy__, NULL);
         if (copyable == NULL) {
             Py_DECREF(result);
             return NULL;
diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index 5d086a7..f4a80c2 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -702,7 +702,9 @@ mmap__enter__method(mmap_object *self, PyObject *args)
 static PyObject *
 mmap__exit__method(PyObject *self, PyObject *args)
 {
-    return PyObject_CallMethod(self, "close", NULL);
+    _Py_identifier(close);
+
+    return _PyObject_CallMethodId(self, &PyId_close, NULL);
 }
 
 static struct PyMethodDef mmap_object_methods[] = {
diff --git a/Modules/ossaudiodev.c b/Modules/ossaudiodev.c
index f0fe8c2..7512c1d 100644
--- a/Modules/ossaudiodev.c
+++ b/Modules/ossaudiodev.c
@@ -534,7 +534,9 @@ oss_self(PyObject *self, PyObject *unused)
 static PyObject *
 oss_exit(PyObject *self, PyObject *unused)
 {
-    PyObject *ret = PyObject_CallMethod(self, "close", NULL);
+    _Py_identifier(close);
+
+    PyObject *ret = _PyObject_CallMethodId(self, &PyId_close, NULL);
     if (!ret)
         return NULL;
     Py_DECREF(ret);
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index e64c960..6d0a44c 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -4821,7 +4821,9 @@ socket_getaddrinfo(PyObject *self, PyObject *args, PyObject* kwargs)
     if (hobj == Py_None) {
         hptr = NULL;
     } else if (PyUnicode_Check(hobj)) {
-        idna = PyObject_CallMethod(hobj, "encode", "s", "idna");
+        _Py_identifier(encode);
+
+        idna = _PyObject_CallMethodId(hobj, &PyId_encode, "s", "idna");
         if (!idna)
             return NULL;
         assert(PyBytes_Check(idna));
diff --git a/Modules/timemodule.c b/Modules/timemodule.c
index 4dc82a0..2ea0247 100644
--- a/Modules/timemodule.c
+++ b/Modules/timemodule.c
@@ -535,11 +535,12 @@ time_strptime(PyObject *self, PyObject *args)
 {
     PyObject *strptime_module = PyImport_ImportModuleNoBlock("_strptime");
     PyObject *strptime_result;
+    _Py_identifier(_strptime_time);
 
     if (!strptime_module)
         return NULL;
-    strptime_result = PyObject_CallMethod(strptime_module,
-                                            "_strptime_time", "O", args);
+    strptime_result = _PyObject_CallMethodId(strptime_module,
+                                             &PyId__strptime_time, "O", args);
     Py_DECREF(strptime_module);
     return strptime_result;
 }
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 9105769..57424a6 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2082,10 +2082,11 @@ PyMapping_Keys(PyObject *o)
 {
     PyObject *keys;
     PyObject *fast;
+    _Py_identifier(keys);
 
     if (PyDict_CheckExact(o))
         return PyDict_Keys(o);
-    keys = PyObject_CallMethod(o, "keys", NULL);
+    keys = _PyObject_CallMethodId(o, &PyId_keys, NULL);
     if (keys == NULL)
         return NULL;
     fast = PySequence_Fast(keys, "o.keys() are not iterable");
@@ -2098,10 +2099,11 @@ PyMapping_Items(PyObject *o)
 {
     PyObject *items;
     PyObject *fast;
+    _Py_identifier(items);
 
     if (PyDict_CheckExact(o))
         return PyDict_Items(o);
-    items = PyObject_CallMethod(o, "items", NULL);
+    items = _PyObject_CallMethodId(o, &PyId_items, NULL);
     if (items == NULL)
         return NULL;
     fast = PySequence_Fast(items, "o.items() are not iterable");
@@ -2114,10 +2116,11 @@ PyMapping_Values(PyObject *o)
 {
     PyObject *values;
     PyObject *fast;
+    _Py_identifier(values);
 
     if (PyDict_CheckExact(o))
         return PyDict_Values(o);
-    values = PyObject_CallMethod(o, "values", NULL);
+    values = _PyObject_CallMethodId(o, &PyId_values, NULL);
     if (values == NULL)
         return NULL;
     fast = PySequence_Fast(values, "o.values() are not iterable");
@@ -2223,22 +2226,11 @@ _PyObject_CallFunction_SizeT(PyObject *callable, char *format, ...)
     return call_function_tail(callable, args);
 }
 
-PyObject *
-PyObject_CallMethod(PyObject *o, char *name, char *format, ...)
+static PyObject*
+callmethod(PyObject* func, char *format, va_list va, int is_size_t)
 {
-    va_list va;
-    PyObject *args;
-    PyObject *func = NULL;
     PyObject *retval = NULL;
-
-    if (o == NULL || name == NULL)
-        return null_error();
-
-    func = PyObject_GetAttrString(o, name);
-    if (func == NULL) {
-        PyErr_SetString(PyExc_AttributeError, name);
-        return 0;
-    }
+    PyObject *args;
 
     if (!PyCallable_Check(func)) {
         type_error("attribute of type '%.200s' is not callable", func);
@@ -2246,9 +2238,10 @@ PyObject_CallMethod(PyObject *o, char *name, char *format, ...)
     }
 
     if (format && *format) {
-        va_start(va, format);
-        args = Py_VaBuildValue(format, va);
-        va_end(va);
+        if (is_size_t)
+            args = _Py_VaBuildValue_SizeT(format, va);
+        else
+            args = Py_VaBuildValue(format, va);
     }
     else
         args = PyTuple_New(0);
@@ -2263,10 +2256,9 @@ PyObject_CallMethod(PyObject *o, char *name, char *format, ...)
 }
 
 PyObject *
-_PyObject_CallMethod_SizeT(PyObject *o, char *name, char *format, ...)
+PyObject_CallMethod(PyObject *o, char *name, char *format, ...)
 {
     va_list va;
-    PyObject *args;
     PyObject *func = NULL;
     PyObject *retval = NULL;
 
@@ -2279,28 +2271,75 @@ _PyObject_CallMethod_SizeT(PyObject *o, char *name, char *format, ...)
         return 0;
     }
 
-    if (!PyCallable_Check(func)) {
-        type_error("attribute of type '%.200s' is not callable", func);
-        goto exit;
-    }
+    va_start(va, format);
+    retval = callmethod(func, format, va, 0);
+    va_end(va);
+    return retval;
+}
 
-    if (format && *format) {
-        va_start(va, format);
-        args = _Py_VaBuildValue_SizeT(format, va);
-        va_end(va);
+PyObject *
+_PyObject_CallMethodId(PyObject *o, _Py_Identifier *name, char *format, ...)
+{
+    va_list va;
+    PyObject *func = NULL;
+    PyObject *retval = NULL;
+
+    if (o == NULL || name == NULL)
+        return null_error();
+
+    func = _PyObject_GetAttrId(o, name);
+    if (func == NULL) {
+        PyErr_SetString(PyExc_AttributeError, name->string);
+        return 0;
     }
-    else
-        args = PyTuple_New(0);
 
-    retval = call_function_tail(func, args);
+    va_start(va, format);
+    retval = callmethod(func, format, va, 0);
+    va_end(va);
+    return retval;
+}
 
-  exit:
-    /* args gets consumed in call_function_tail */
-    Py_XDECREF(func);
+PyObject *
+_PyObject_CallMethod_SizeT(PyObject *o, char *name, char *format, ...)
+{
+    va_list va;
+    PyObject *func = NULL;
+    PyObject *retval;
+
+    if (o == NULL || name == NULL)
+        return null_error();
 
+    func = PyObject_GetAttrString(o, name);
+    if (func == NULL) {
+        PyErr_SetString(PyExc_AttributeError, name);
+        return 0;
+    }
+    va_start(va, format);
+    retval = callmethod(func, format, va, 1);
+    va_end(va);
     return retval;
 }
 
+PyObject *
+_PyObject_CallMethodId_SizeT(PyObject *o, _Py_Identifier *name, char *format, ...)
+{
+    va_list va;
+    PyObject *func = NULL;
+    PyObject *retval;
+
+    if (o == NULL || name == NULL)
+        return null_error();
+
+    func = _PyObject_GetAttrId(o, name);
+    if (func == NULL) {
+        PyErr_SetString(PyExc_AttributeError, name->string);
+        return NULL;
+    }
+    va_start(va, format);
+    retval = callmethod(func, format, va, 1);
+    va_end(va);
+    return retval;
+}
 
 static PyObject *
 objargs_mktuple(va_list va)
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index a786bae..046eebd 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -703,34 +703,39 @@ static PyObject *
 proxy_get(proxyobject *pp, PyObject *args)
 {
     PyObject *key, *def = Py_None;
+    _Py_identifier(get);
 
     if (!PyArg_UnpackTuple(args, "get", 1, 2, &key, &def))
         return NULL;
-    return PyObject_CallMethod(pp->dict, "get", "(OO)", key, def);
+    return _PyObject_CallMethodId(pp->dict, &PyId_get, "(OO)", key, def);
 }
 
 static PyObject *
 proxy_keys(proxyobject *pp)
 {
-    return PyObject_CallMethod(pp->dict, "keys", NULL);
+    _Py_identifier(keys);
+    return _PyObject_CallMethodId(pp->dict, &PyId_keys, NULL);
 }
 
 static PyObject *
 proxy_values(proxyobject *pp)
 {
-    return PyObject_CallMethod(pp->dict, "values", NULL);
+    _Py_identifier(values);
+    return _PyObject_CallMethodId(pp->dict, &PyId_values, NULL);
 }
 
 static PyObject *
 proxy_items(proxyobject *pp)
 {
-    return PyObject_CallMethod(pp->dict, "items", NULL);
+    _Py_identifier(items);
+    return _PyObject_CallMethodId(pp->dict, &PyId_items, NULL);
 }
 
 static PyObject *
 proxy_copy(proxyobject *pp)
 {
-    return PyObject_CallMethod(pp->dict, "copy", NULL);
+    _Py_identifier(copy);
+    return _PyObject_CallMethodId(pp->dict, &PyId_copy, NULL);
 }
 
 static PyMethodDef proxy_methods[] = {
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index c4265da..220e621 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -2707,10 +2707,12 @@ dictviews_sub(PyObject* self, PyObject *other)
 {
     PyObject *result = PySet_New(self);
     PyObject *tmp;
+    _Py_identifier(difference_update);
+
     if (result == NULL)
         return NULL;
 
-    tmp = PyObject_CallMethod(result, "difference_update", "O", other);
+    tmp = _PyObject_CallMethodId(result, &PyId_difference_update, "O", other);
     if (tmp == NULL) {
         Py_DECREF(result);
         return NULL;
@@ -2725,10 +2727,12 @@ dictviews_and(PyObject* self, PyObject *other)
 {
     PyObject *result = PySet_New(self);
     PyObject *tmp;
+    _Py_identifier(intersection_update);
+
     if (result == NULL)
         return NULL;
 
-    tmp = PyObject_CallMethod(result, "intersection_update", "O", other);
+    tmp = _PyObject_CallMethodId(result, &PyId_intersection_update, "O", other);
     if (tmp == NULL) {
         Py_DECREF(result);
         return NULL;
@@ -2761,10 +2765,12 @@ dictviews_xor(PyObject* self, PyObject *other)
 {
     PyObject *result = PySet_New(self);
     PyObject *tmp;
+    _Py_identifier(symmetric_difference_update);
+
     if (result == NULL)
         return NULL;
 
-    tmp = PyObject_CallMethod(result, "symmetric_difference_update", "O",
+    tmp = _PyObject_CallMethodId(result, &PyId_symmetric_difference_update, "O",
                               other);
     if (tmp == NULL) {
         Py_DECREF(result);
diff --git a/Objects/fileobject.c b/Objects/fileobject.c
index 6421543..f3006d0 100644
--- a/Objects/fileobject.c
+++ b/Objects/fileobject.c
@@ -30,11 +30,12 @@ PyFile_FromFd(int fd, char *name, char *mode, int buffering, char *encoding,
               char *errors, char *newline, int closefd)
 {
     PyObject *io, *stream;
+    _Py_identifier(open);
 
     io = PyImport_ImportModule("io");
     if (io == NULL)
         return NULL;
-    stream = PyObject_CallMethod(io, "open", "isisssi", fd, mode,
+    stream = _PyObject_CallMethodId(io, &PyId_open, "isisssi", fd, mode,
                                  buffering, encoding, errors,
                                  newline, closefd);
     Py_DECREF(io);
diff --git a/Objects/object.c b/Objects/object.c
index aeaa4b5..7db60f3 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -811,6 +811,42 @@ PyObject_SetAttrString(PyObject *v, const char *name, PyObject *w)
 }
 
 PyObject *
+_PyObject_GetAttrId(PyObject *v, _Py_Identifier *name)
+{
+    PyObject *result;
+    PyObject *oname = _PyUnicode_FromId(name);
+    if (!oname)
+        return NULL;
+    result = PyObject_GetAttr(v, oname);
+    Py_DECREF(oname);
+    return result;
+}
+
+int
+_PyObject_HasAttrId(PyObject *v, _Py_Identifier *name)
+{
+    int result;
+    PyObject *oname = _PyUnicode_FromId(name);
+    if (!oname)
+        return -1;
+    result = PyObject_HasAttr(v, oname);
+    Py_DECREF(oname);
+    return result;
+}
+
+int
+_PyObject_SetAttrId(PyObject *v, _Py_Identifier *name, PyObject *w)
+{
+    int result;
+    PyObject *oname = _PyUnicode_FromId(name);
+    if (!oname)
+        return -1;
+    result = PyObject_SetAttr(v, oname, w);
+    Py_DECREF(oname);
+    return result;
+}
+
+PyObject *
 PyObject_GetAttr(PyObject *v, PyObject *name)
 {
     PyTypeObject *tp = Py_TYPE(v);
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 2e6eb0a..f94dfbf 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2897,6 +2897,7 @@ object_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
         PyObject *sorted;
         PyObject *sorted_methods = NULL;
         PyObject *joined = NULL;
+        _Py_identifier(join);
 
         /* Compute ", ".join(sorted(type.__abstractmethods__))
            into joined. */
@@ -2919,7 +2920,7 @@ object_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
             if (comma == NULL)
                 goto error;
         }
-        joined = PyObject_CallMethod(comma, "join",
+        joined = _PyObject_CallMethodId(comma, &PyId_join,
                                      "O",  sorted_methods);
         if (joined == NULL)
             goto error;
@@ -3184,6 +3185,7 @@ slotnames(PyObject *cls)
     PyObject *copyreg;
     PyObject *slotnames;
     static PyObject *str_slotnames;
+    _Py_identifier(_slotnames);
 
     if (str_slotnames == NULL) {
         str_slotnames = PyUnicode_InternFromString("__slotnames__");
@@ -3202,7 +3204,7 @@ slotnames(PyObject *cls)
     if (copyreg == NULL)
         return NULL;
 
-    slotnames = PyObject_CallMethod(copyreg, "_slotnames", "O", cls);
+    slotnames = _PyObject_CallMethodId(copyreg, &PyId__slotnames, "O", cls);
     Py_DECREF(copyreg);
     if (slotnames != NULL &&
         slotnames != Py_None &&
@@ -3323,7 +3325,8 @@ reduce_2(PyObject *obj)
         Py_INCREF(dictitems);
     }
     else {
-        PyObject *items = PyObject_CallMethod(obj, "items", "");
+        _Py_identifier(items);
+        PyObject *items = _PyObject_CallMethodId(obj, &PyId_items, "");
         if (items == NULL)
             goto end;
         dictitems = PyObject_GetIter(items);
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index e904b6e..af92368 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -201,6 +201,9 @@ static PyObject *interned;
 /* The empty Unicode object is shared to improve performance. */
 static PyObject *unicode_empty;
 
+/* List of static strings. */
+static _Py_Identifier *static_strings;
+
 /* Single character Unicode strings in the Latin-1 range are being
    shared as well. */
 static PyObject *unicode_latin1[256];
@@ -1609,6 +1612,33 @@ PyUnicode_FromString(const char *u)
     return PyUnicode_FromStringAndSize(u, size);
 }
 
+PyObject *
+_PyUnicode_FromId(_Py_Identifier *id)
+{
+    if (!id->object) {
+        id->object = PyUnicode_FromString(id->string);
+        if (!id->object)
+            return NULL;
+        PyUnicode_InternInPlace(&id->object);
+        assert(!id->next);
+        id->next = static_strings;
+        static_strings = id;
+    }
+    Py_INCREF(id->object);
+    return id->object;
+}
+
+void
+_PyUnicode_ClearStaticStrings()
+{
+    _Py_Identifier *i;
+    for (i = static_strings; i; i = i->next) {
+        Py_DECREF(i->object);
+        i->object = NULL;
+        i->next = NULL;
+    }
+}
+
 static PyObject*
 unicode_fromascii(const unsigned char* s, Py_ssize_t size)
 {
@@ -13523,6 +13553,7 @@ _PyUnicode_Fini(void)
             unicode_latin1[i] = NULL;
         }
     }
+    _PyUnicode_ClearStaticStrings();
     (void)PyUnicode_ClearFreeList();
 }
 
diff --git a/Objects/weakrefobject.c b/Objects/weakrefobject.c
index c99f6ba..594f0ea 100644
--- a/Objects/weakrefobject.c
+++ b/Objects/weakrefobject.c
@@ -440,8 +440,9 @@ proxy_checkref(PyWeakReference *proxy)
 #define WRAP_METHOD(method, special) \
     static PyObject * \
     method(PyObject *proxy) { \
+            _Py_identifier(special); \
             UNWRAP(proxy); \
-                return PyObject_CallMethod(proxy, special, ""); \
+                return _PyObject_CallMethodId(proxy, &PyId_##special, ""); \
         }
 
 
@@ -584,7 +585,7 @@ proxy_iternext(PyWeakReference *proxy)
 }
 
 
-WRAP_METHOD(proxy_bytes, "__bytes__")
+WRAP_METHOD(proxy_bytes, __bytes__)
 
 
 static PyMethodDef proxy_methods[] = {
diff --git a/PC/_msi.c b/PC/_msi.c
index d4d8483..54406df 100644
--- a/PC/_msi.c
+++ b/PC/_msi.c
@@ -122,7 +122,9 @@ static FNFCIGETTEMPFILE(cb_gettempfile)
 static FNFCISTATUS(cb_status)
 {
     if (pv) {
-        PyObject *result = PyObject_CallMethod(pv, "status", "iii", typeStatus, cb1, cb2);
+        _Py_identifier(status);
+
+        PyObject *result = _PyObject_CallMethodId(pv, &PyId_status, "iii", typeStatus, cb1, cb2);
         if (result == NULL)
             return -1;
         Py_DECREF(result);
@@ -133,7 +135,9 @@ static FNFCISTATUS(cb_status)
 static FNFCIGETNEXTCABINET(cb_getnextcabinet)
 {
     if (pv) {
-        PyObject *result = PyObject_CallMethod(pv, "getnextcabinet", "i", pccab->iCab);
+        _Py_identifier(getnextcabinet);
+
+        PyObject *result = _PyObject_CallMethodId(pv, &PyId_getnextcabinet, "i", pccab->iCab);
         if (result == NULL)
             return -1;
         if (!PyBytes_Check(result)) {
diff --git a/Parser/tokenizer.c b/Parser/tokenizer.c
index a0a3a67..23ea2eb 100644
--- a/Parser/tokenizer.c
+++ b/Parser/tokenizer.c
@@ -462,6 +462,7 @@ static int
 fp_setreadl(struct tok_state *tok, const char* enc)
 {
     PyObject *readline = NULL, *stream = NULL, *io = NULL;
+    _Py_identifier(open);
     int fd;
 
     io = PyImport_ImportModuleNoBlock("io");
@@ -474,7 +475,7 @@ fp_setreadl(struct tok_state *tok, const char* enc)
         goto cleanup;
     }
 
-    stream = PyObject_CallMethod(io, "open", "isisOOO",
+    stream = _PyObject_CallMethodId(io, &PyId_open, "isisOOO",
                     fd, "r", -1, enc, Py_None, Py_None, Py_False);
     if (stream == NULL)
         goto cleanup;
diff --git a/Python/_warnings.c b/Python/_warnings.c
index 792e3ed..e563107 100644
--- a/Python/_warnings.c
+++ b/Python/_warnings.c
@@ -18,11 +18,12 @@ static int
 check_matched(PyObject *obj, PyObject *arg)
 {
     PyObject *result;
+    _Py_identifier(match);
     int rc;
 
     if (obj == Py_None)
         return 1;
-    result = PyObject_CallMethod(obj, "match", "O", arg);
+    result = _PyObject_CallMethodId(obj, &PyId_match, "O", arg);
     if (result == NULL)
         return -1;
 
diff --git a/Python/ast.c b/Python/ast.c
index a52fd09..9872979 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -527,6 +527,7 @@ static PyObject *parsestrplus(struct compiling *, const node *n,
 static identifier
 new_identifier(const char* n, PyArena *arena)
 {
+    _Py_identifier(normalize);
     PyObject* id = PyUnicode_DecodeUTF8(n, strlen(n), NULL);
     if (!id || PyUnicode_READY(id) == -1)
         return NULL;
@@ -537,7 +538,7 @@ new_identifier(const char* n, PyArena *arena)
         PyObject *id2;
         if (!m)
             return NULL;
-        id2 = PyObject_CallMethod(m, "normalize", "sO", "NFKC", id);
+        id2 = _PyObject_CallMethodId(m, &PyId_normalize, "sO", "NFKC", id);
         Py_DECREF(m);
         if (!id2)
             return NULL;
diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 04f5231..c174e9d 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -32,6 +32,9 @@ const char *Py_FileSystemDefaultEncoding = NULL; /* set by initfsencoding() */
 int Py_HasFileSystemDefaultEncoding = 0;
 #endif
 
+_Py_identifier(fileno);
+_Py_identifier(flush);
+
 static PyObject *
 builtin___build_class__(PyObject *self, PyObject *args, PyObject *kwds)
 {
@@ -1567,7 +1570,7 @@ builtin_input(PyObject *self, PyObject *args)
     }
 
     /* First of all, flush stderr */
-    tmp = PyObject_CallMethod(ferr, "flush", "");
+    tmp = _PyObject_CallMethodId(ferr, &PyId_flush, "");
     if (tmp == NULL)
         PyErr_Clear();
     else
@@ -1576,7 +1579,7 @@ builtin_input(PyObject *self, PyObject *args)
     /* We should only use (GNU) readline if Python's sys.stdin and
        sys.stdout are the same as C's stdin and stdout, because we
        need to pass it those. */
-    tmp = PyObject_CallMethod(fin, "fileno", "");
+    tmp = _PyObject_CallMethodId(fin, &PyId_fileno, "");
     if (tmp == NULL) {
         PyErr_Clear();
         tty = 0;
@@ -1589,7 +1592,7 @@ builtin_input(PyObject *self, PyObject *args)
         tty = fd == fileno(stdin) && isatty(fd);
     }
     if (tty) {
-        tmp = PyObject_CallMethod(fout, "fileno", "");
+        tmp = _PyObject_CallMethodId(fout, &PyId_fileno, "");
         if (tmp == NULL)
             PyErr_Clear();
         else {
@@ -1621,7 +1624,7 @@ builtin_input(PyObject *self, PyObject *args)
             Py_DECREF(stdin_encoding);
             return NULL;
         }
-        tmp = PyObject_CallMethod(fout, "flush", "");
+        tmp = _PyObject_CallMethodId(fout, &PyId_flush, "");
         if (tmp == NULL)
             PyErr_Clear();
         else
@@ -1703,7 +1706,7 @@ builtin_input(PyObject *self, PyObject *args)
         if (PyFile_WriteObject(promptarg, fout, Py_PRINT_RAW) != 0)
             return NULL;
     }
-    tmp = PyObject_CallMethod(fout, "flush", "");
+    tmp = _PyObject_CallMethodId(fout, &PyId_flush, "");
     if (tmp == NULL)
         PyErr_Clear();
     else
diff --git a/Python/ceval.c b/Python/ceval.c
index 686a54d..04d3df1 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -372,6 +372,7 @@ PyEval_ReleaseThread(PyThreadState *tstate)
 void
 PyEval_ReInitThreads(void)
 {
+    _Py_identifier(_after_fork);
     PyObject *threading, *result;
     PyThreadState *tstate = PyThreadState_GET();
 
@@ -392,7 +393,7 @@ PyEval_ReInitThreads(void)
         PyErr_Clear();
         return;
     }
-    result = PyObject_CallMethod(threading, "_after_fork", NULL);
+    result = _PyObject_CallMethodId(threading, &PyId__after_fork, NULL);
     if (result == NULL)
         PyErr_WriteUnraisable(threading);
     else
diff --git a/Python/import.c b/Python/import.c
index 5f84ac2..6eca90a 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -1801,6 +1801,7 @@ find_module_path(PyObject *fullname, PyObject *name, PyObject *path,
 
     /* sys.path_hooks import hook */
     if (p_loader != NULL) {
+        _Py_identifier(find_module);
         PyObject *importer;
 
         importer = get_path_importer(path_importer_cache,
@@ -1811,8 +1812,8 @@ find_module_path(PyObject *fullname, PyObject *name, PyObject *path,
         /* Note: importer is a borrowed reference */
         if (importer != Py_None) {
             PyObject *loader;
-            loader = PyObject_CallMethod(importer,
-                                         "find_module", "O", fullname);
+            loader = _PyObject_CallMethodId(importer,
+                                            &PyId_find_module, "O", fullname);
             if (loader == NULL)
                 return -1;  /* error */
             if (loader != Py_None) {
@@ -2030,6 +2031,7 @@ find_module(PyObject *fullname, PyObject *name, PyObject *search_path_list,
 
     /* sys.meta_path import hook */
     if (p_loader != NULL) {
+        _Py_identifier(find_module);
         PyObject *meta_path;
 
         meta_path = PySys_GetObject("meta_path");
@@ -2044,7 +2046,7 @@ find_module(PyObject *fullname, PyObject *name, PyObject *search_path_list,
         for (i = 0; i < npath; i++) {
             PyObject *loader;
             PyObject *hook = PyList_GetItem(meta_path, i);
-            loader = PyObject_CallMethod(hook, "find_module",
+            loader = _PyObject_CallMethodId(hook, &PyId_find_module,
                                          "OO", fullname,
                                          search_path_list != NULL ?
                                          search_path_list : Py_None);
@@ -2454,12 +2456,13 @@ load_module(PyObject *name, FILE *fp, PyObject *pathname, int type, PyObject *lo
         break;
 
     case IMP_HOOK: {
+        _Py_identifier(load_module);
         if (loader == NULL) {
             PyErr_SetString(PyExc_ImportError,
                             "import hook without loader");
             return NULL;
         }
-        m = PyObject_CallMethod(loader, "load_module", "O", name);
+        m = _PyObject_CallMethodId(loader, &PyId_load_module, "O", name);
         break;
     }
 
diff --git a/Python/marshal.c b/Python/marshal.c
index 31fe66b..b8288d0 100644
--- a/Python/marshal.c
+++ b/Python/marshal.c
@@ -480,7 +480,9 @@ r_string(char *s, int n, RFILE *p)
         }
     }
     else {
-        PyObject *data = PyObject_CallMethod(p->readable, "read", "i", n);
+        _Py_identifier(read);
+
+        PyObject *data = _PyObject_CallMethodId(p->readable, &PyId_read, "i", n);
         read = 0;
         if (data != NULL) {
             if (!PyBytes_Check(data)) {
@@ -1290,12 +1292,14 @@ marshal_dump(PyObject *self, PyObject *args)
     int version = Py_MARSHAL_VERSION;
     PyObject *s;
     PyObject *res;
+    _Py_identifier(write);
+
     if (!PyArg_ParseTuple(args, "OO|i:dump", &x, &f, &version))
         return NULL;
     s = PyMarshal_WriteObjectToString(x, version);
     if (s == NULL)
         return NULL;
-    res = PyObject_CallMethod(f, "write", "O", s);
+    res = _PyObject_CallMethodId(f, &PyId_write, "O", s);
     Py_DECREF(s);
     return res;
 }
@@ -1317,6 +1321,7 @@ static PyObject *
 marshal_load(PyObject *self, PyObject *f)
 {
     PyObject *data, *result;
+    _Py_identifier(read);
     RFILE rf;
 
     /*
@@ -1324,7 +1329,7 @@ marshal_load(PyObject *self, PyObject *f)
      * This is to ensure that the object passed in at least
      * has a read method which returns bytes.
      */
-    data = PyObject_CallMethod(f, "read", "i", 0);
+    data = _PyObject_CallMethodId(f, &PyId_read, "i", 0);
     if (data == NULL)
         return NULL;
     if (!PyBytes_Check(data)) {
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index 1888fba..0ef36bb 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -352,9 +352,10 @@ flush_std_files(void)
     PyObject *fout = PySys_GetObject("stdout");
     PyObject *ferr = PySys_GetObject("stderr");
     PyObject *tmp;
+    _Py_identifier(flush);
 
     if (fout != NULL && fout != Py_None) {
-        tmp = PyObject_CallMethod(fout, "flush", "");
+        tmp = _PyObject_CallMethodId(fout, &PyId_flush, "");
         if (tmp == NULL)
             PyErr_WriteUnraisable(fout);
         else
@@ -362,7 +363,7 @@ flush_std_files(void)
     }
 
     if (ferr != NULL && ferr != Py_None) {
-        tmp = PyObject_CallMethod(ferr, "flush", "");
+        tmp = _PyObject_CallMethodId(ferr, &PyId_flush, "");
         if (tmp == NULL)
             PyErr_Clear();
         else
@@ -805,6 +806,9 @@ create_stdio(PyObject* io,
     const char* newline;
     PyObject *line_buffering;
     int buffering, isatty;
+    _Py_identifier(open);
+    _Py_identifier(isatty);
+    _Py_identifier(TextIOWrapper);
 
     /* stdin is always opened in buffered mode, first because it shouldn't
        make a difference in common use cases, second because TextIOWrapper
@@ -819,9 +823,9 @@ create_stdio(PyObject* io,
         mode = "wb";
     else
         mode = "rb";
-    buf = PyObject_CallMethod(io, "open", "isiOOOi",
-                              fd, mode, buffering,
-                              Py_None, Py_None, Py_None, 0);
+    buf = _PyObject_CallMethodId(io, &PyId_open, "isiOOOi",
+                                 fd, mode, buffering,
+                                 Py_None, Py_None, Py_None, 0);
     if (buf == NULL)
         goto error;
 
@@ -838,7 +842,7 @@ create_stdio(PyObject* io,
     text = PyUnicode_FromString(name);
     if (text == NULL || PyObject_SetAttrString(raw, "name", text) < 0)
         goto error;
-    res = PyObject_CallMethod(raw, "isatty", "");
+    res = _PyObject_CallMethodId(raw, &PyId_isatty, "");
     if (res == NULL)
         goto error;
     isatty = PyObject_IsTrue(res);
@@ -861,9 +865,9 @@ create_stdio(PyObject* io,
     }
 #endif
 
-    stream = PyObject_CallMethod(io, "TextIOWrapper", "OsssO",
-                                 buf, encoding, errors,
-                                 newline, line_buffering);
+    stream = _PyObject_CallMethodId(io, &PyId_TextIOWrapper, "OsssO",
+                                    buf, encoding, errors,
+                                    newline, line_buffering);
     Py_CLEAR(buf);
     if (stream == NULL)
         goto error;
@@ -1759,13 +1763,14 @@ flush_io(void)
 {
     PyObject *f, *r;
     PyObject *type, *value, *traceback;
+    _Py_identifier(flush);
 
     /* Save the current exception */
     PyErr_Fetch(&type, &value, &traceback);
 
     f = PySys_GetObject("stderr");
     if (f != NULL) {
-        r = PyObject_CallMethod(f, "flush", "");
+        r = _PyObject_CallMethodId(f, &PyId_flush, "");
         if (r)
             Py_DECREF(r);
         else
@@ -1773,7 +1778,7 @@ flush_io(void)
     }
     f = PySys_GetObject("stdout");
     if (f != NULL) {
-        r = PyObject_CallMethod(f, "flush", "");
+        r = _PyObject_CallMethodId(f, &PyId_flush, "");
         if (r)
             Py_DECREF(r);
         else
@@ -2205,6 +2210,7 @@ static void
 wait_for_thread_shutdown(void)
 {
 #ifdef WITH_THREAD
+    _Py_identifier(_shutdown);
     PyObject *result;
     PyThreadState *tstate = PyThreadState_GET();
     PyObject *threading = PyMapping_GetItemString(tstate->interp->modules,
@@ -2214,7 +2220,7 @@ wait_for_thread_shutdown(void)
         PyErr_Clear();
         return;
     }
-    result = PyObject_CallMethod(threading, "_shutdown", "");
+    result = _PyObject_CallMethodId(threading, &PyId__shutdown, "");
     if (result == NULL) {
         PyErr_WriteUnraisable(threading);
     }
diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 3576ced..f0acead 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -99,7 +99,8 @@ sys_displayhook_unencodable(PyObject *outf, PyObject *o)
 
     buffer = PyObject_GetAttrString(outf, "buffer");
     if (buffer) {
-        result = PyObject_CallMethod(buffer, "write", "(O)", encoded);
+        _Py_identifier(write);
+        result = _PyObject_CallMethodId(buffer, &PyId_write, "(O)", encoded);
         Py_DECREF(buffer);
         Py_DECREF(encoded);
         if (result == NULL)
diff --git a/Python/traceback.c b/Python/traceback.c
index b66c96c..551f9d6 100644
--- a/Python/traceback.c
+++ b/Python/traceback.c
@@ -152,6 +152,7 @@ _Py_FindSourceFile(PyObject *filename, char* namebuf, size_t namelen, PyObject *
     const char* filepath;
     Py_ssize_t len;
     PyObject* result;
+    _Py_identifier(open);
 
     filebytes = PyUnicode_EncodeFSDefault(filename);
     if (filebytes == NULL) {
@@ -199,7 +200,7 @@ _Py_FindSourceFile(PyObject *filename, char* namebuf, size_t namelen, PyObject *
             namebuf[len++] = SEP;
         strcpy(namebuf+len, tail);
 
-        binary = PyObject_CallMethod(io, "open", "ss", namebuf, "rb");
+        binary = _PyObject_CallMethodId(io, &PyId_open, "ss", namebuf, "rb");
         if (binary != NULL) {
             result = binary;
             goto finally;
@@ -231,6 +232,9 @@ _Py_DisplaySourceLine(PyObject *f, PyObject *filename, int lineno, int indent)
     char buf[MAXPATHLEN+1];
     int kind;
     void *data;
+    _Py_identifier(close);
+    _Py_identifier(open);
+    _Py_identifier(TextIOWrapper);
 
     /* open the file */
     if (filename == NULL)
@@ -239,7 +243,7 @@ _Py_DisplaySourceLine(PyObject *f, PyObject *filename, int lineno, int indent)
     io = PyImport_ImportModuleNoBlock("io");
     if (io == NULL)
         return -1;
-    binary = PyObject_CallMethod(io, "open", "Os", filename, "rb");
+    binary = _PyObject_CallMethodId(io, &PyId_open, "Os", filename, "rb");
 
     if (binary == NULL) {
         binary = _Py_FindSourceFile(filename, buf, sizeof(buf), io);
@@ -254,7 +258,7 @@ _Py_DisplaySourceLine(PyObject *f, PyObject *filename, int lineno, int indent)
     found_encoding = PyTokenizer_FindEncodingFilename(fd, filename);
     encoding = (found_encoding != NULL) ? found_encoding : "utf-8";
     lseek(fd, 0, 0); /* Reset position */
-    fob = PyObject_CallMethod(io, "TextIOWrapper", "Os", binary, encoding);
+    fob = _PyObject_CallMethodId(io, &PyId_TextIOWrapper, "Os", binary, encoding);
     Py_DECREF(io);
     Py_DECREF(binary);
     PyMem_FREE(found_encoding);
@@ -273,7 +277,7 @@ _Py_DisplaySourceLine(PyObject *f, PyObject *filename, int lineno, int indent)
             break;
         }
     }
-    res = PyObject_CallMethod(fob, "close", "");
+    res = _PyObject_CallMethodId(fob, &PyId_close, "");
     if (res)
         Py_DECREF(res);
     else