diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 504b119..16affdd 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -421,7 +421,7 @@
     if (!PyString_Check(v)) {
         PyErr_Format(PyExc_TypeError,
                      "decoder did not return a string object (type=%.400s)",
-                     v->ob_type->tp_name);
+                     Py_Type(v)->tp_name);
         Py_DECREF(v);
         goto onError;
     }
@@ -501,7 +501,7 @@
     if (!PyString_Check(v)) {
         PyErr_Format(PyExc_TypeError,
                      "encoder did not return a string object (type=%.400s)",
-                     v->ob_type->tp_name);
+                     Py_Type(v)->tp_name);
         Py_DECREF(v);
         goto onError;
     }
@@ -521,7 +521,7 @@
 
 		case SSTATE_INTERNED_MORTAL:
 			/* revive dead object temporarily for DelItem */
-			op->ob_refcnt = 3;
+			Py_Refcnt(op) = 3;
 			if (PyDict_DelItem(interned, op) != 0)
 				Py_FatalError(
 					"deletion of interned string failed");
@@ -533,7 +533,7 @@
 		default:
 			Py_FatalError("Inconsistent interned string state.");
 	}
-	op->ob_type->tp_free(op);
+	Py_Type(op)->tp_free(op);
 }
 
 /* Unescape a backslash-escaped string. If unicode is non-zero,
@@ -717,7 +717,7 @@
 {
 	if (!PyString_Check(op))
 		return string_getsize(op);
-	return ((PyStringObject *)op) -> ob_size;
+	return Py_Size(op);
 }
 
 /*const*/ char *
@@ -750,7 +750,7 @@
 		{
 			PyErr_Format(PyExc_TypeError,
 				     "expected string or Unicode object, "
-				     "%.200s found", obj->ob_type->tp_name);
+				     "%.200s found", Py_Type(obj)->tp_name);
 			return -1;
 		}
 	}
@@ -805,7 +805,7 @@
 	}
 	if (flags & Py_PRINT_RAW) {
 		char *data = op->ob_sval;
-		Py_ssize_t size = op->ob_size;
+		Py_ssize_t size = Py_Size(op);
 		while (size > INT_MAX) {
 			/* Very long strings cannot be written atomically.
 			 * But don't write exactly INT_MAX bytes at a time
@@ -826,12 +826,12 @@
 
 	/* figure out which quote to use; single is preferred */
 	quote = '\'';
-	if (memchr(op->ob_sval, '\'', op->ob_size) &&
-	    !memchr(op->ob_sval, '"', op->ob_size))
+	if (memchr(op->ob_sval, '\'', Py_Size(op)) &&
+	    !memchr(op->ob_sval, '"', Py_Size(op)))
 		quote = '"';
 
 	fputc(quote, fp);
-	for (i = 0; i < op->ob_size; i++) {
+	for (i = 0; i < Py_Size(op); i++) {
 		c = op->ob_sval[i];
 		if (c == quote || c == '\\')
 			fprintf(fp, "\\%c", c);
@@ -854,9 +854,9 @@
 PyString_Repr(PyObject *obj, int smartquotes)
 {
 	register PyStringObject* op = (PyStringObject*) obj;
-	size_t newsize = 2 + 4 * op->ob_size;
+	size_t newsize = 2 + 4 * Py_Size(op);
 	PyObject *v;
-	if (newsize > PY_SSIZE_T_MAX || newsize / 4 != op->ob_size) {
+	if (newsize > PY_SSIZE_T_MAX || newsize / 4 != Py_Size(op)) {
 		PyErr_SetString(PyExc_OverflowError,
 			"string is too large to make repr");
 	}
@@ -873,13 +873,13 @@
 		/* figure out which quote to use; single is preferred */
 		quote = '\'';
 		if (smartquotes &&
-		    memchr(op->ob_sval, '\'', op->ob_size) &&
-		    !memchr(op->ob_sval, '"', op->ob_size))
+		    memchr(op->ob_sval, '\'', Py_Size(op)) &&
+		    !memchr(op->ob_sval, '"', Py_Size(op)))
 			quote = '"';
 
 		p = PyString_AS_STRING(v);
 		*p++ = quote;
-		for (i = 0; i < op->ob_size; i++) {
+		for (i = 0; i < Py_Size(op); i++) {
 			/* There's at least enough room for a hex escape
 			   and a closing quote. */
 			assert(newsize - (p - PyString_AS_STRING(v)) >= 5);
@@ -928,14 +928,14 @@
 	else {
 		/* Subtype -- return genuine string with the same value. */
 		PyStringObject *t = (PyStringObject *) s;
-		return PyString_FromStringAndSize(t->ob_sval, t->ob_size);
+		return PyString_FromStringAndSize(t->ob_sval, Py_Size(t));
 	}
 }
 
 static Py_ssize_t
 string_length(PyStringObject *a)
 {
-	return a->ob_size;
+	return Py_Size(a);
 }
 
 static PyObject *
@@ -950,21 +950,21 @@
 #endif
 		PyErr_Format(PyExc_TypeError,
 			     "cannot concatenate 'str' and '%.200s' objects",
-			     bb->ob_type->tp_name);
+			     Py_Type(bb)->tp_name);
 		return NULL;
 	}
 #define b ((PyStringObject *)bb)
 	/* Optimize cases with empty left or right operand */
-	if ((a->ob_size == 0 || b->ob_size == 0) &&
+	if ((Py_Size(a) == 0 || Py_Size(b) == 0) &&
 	    PyString_CheckExact(a) && PyString_CheckExact(b)) {
-		if (a->ob_size == 0) {
+		if (Py_Size(a) == 0) {
 			Py_INCREF(bb);
 			return bb;
 		}
 		Py_INCREF(a);
 		return (PyObject *)a;
 	}
-	size = a->ob_size + b->ob_size;
+	size = Py_Size(a) + Py_Size(b);
 	if (size < 0) {
 		PyErr_SetString(PyExc_OverflowError,
 				"strings are too large to concat");
@@ -978,8 +978,8 @@
 	PyObject_INIT_VAR(op, &PyString_Type, size);
 	op->ob_shash = -1;
 	op->ob_sstate = SSTATE_NOT_INTERNED;
-	Py_MEMCPY(op->ob_sval, a->ob_sval, a->ob_size);
-	Py_MEMCPY(op->ob_sval + a->ob_size, b->ob_sval, b->ob_size);
+	Py_MEMCPY(op->ob_sval, a->ob_sval, Py_Size(a));
+	Py_MEMCPY(op->ob_sval + Py_Size(a), b->ob_sval, Py_Size(b));
 	op->ob_sval[size] = '\0';
 	return (PyObject *) op;
 #undef b
@@ -998,13 +998,13 @@
 	/* watch out for overflows:  the size can overflow int,
 	 * and the # of bytes needed can overflow size_t
 	 */
-	size = a->ob_size * n;
-	if (n && size / n != a->ob_size) {
+	size = Py_Size(a) * n;
+	if (n && size / n != Py_Size(a)) {
 		PyErr_SetString(PyExc_OverflowError,
 			"repeated string is too long");
 		return NULL;
 	}
-	if (size == a->ob_size && PyString_CheckExact(a)) {
+	if (size == Py_Size(a) && PyString_CheckExact(a)) {
 		Py_INCREF(a);
 		return (PyObject *)a;
 	}
@@ -1022,14 +1022,14 @@
 	op->ob_shash = -1;
 	op->ob_sstate = SSTATE_NOT_INTERNED;
 	op->ob_sval[size] = '\0';
-	if (a->ob_size == 1 && n > 0) {
+	if (Py_Size(a) == 1 && n > 0) {
 		memset(op->ob_sval, a->ob_sval[0] , n);
 		return (PyObject *) op;
 	}
 	i = 0;
 	if (i < size) {
-		Py_MEMCPY(op->ob_sval, a->ob_sval, a->ob_size);
-		i = a->ob_size;
+		Py_MEMCPY(op->ob_sval, a->ob_sval, Py_Size(a));
+		i = Py_Size(a);
 	}
 	while (i < size) {
 		j = (i <= size-i)  ?  i  :  size-i;
@@ -1050,9 +1050,9 @@
 		i = 0;
 	if (j < 0)
 		j = 0; /* Avoid signed/unsigned bug in next line */
-	if (j > a->ob_size)
-		j = a->ob_size;
-	if (i == 0 && j == a->ob_size && PyString_CheckExact(a)) {
+	if (j > Py_Size(a))
+		j = Py_Size(a);
+	if (i == 0 && j == Py_Size(a) && PyString_CheckExact(a)) {
 		/* It's the same as a */
 		Py_INCREF(a);
 		return (PyObject *)a;
@@ -1073,7 +1073,7 @@
 		if (!PyString_Check(sub_obj)) {
 			PyErr_Format(PyExc_TypeError,
 			    "'in <string>' requires string as left operand, "
-			    "not %.200s", sub_obj->ob_type->tp_name);
+			    "not %.200s", Py_Type(sub_obj)->tp_name);
 			return -1;
 		}
 	}
@@ -1086,7 +1086,7 @@
 {
 	char pchar;
 	PyObject *v;
-	if (i < 0 || i >= a->ob_size) {
+	if (i < 0 || i >= Py_Size(a)) {
 		PyErr_SetString(PyExc_IndexError, "string index out of range");
 		return NULL;
 	}
@@ -1129,16 +1129,16 @@
 	if (op == Py_EQ) {
 		/* Supporting Py_NE here as well does not save
 		   much time, since Py_NE is rarely used.  */
-		if (a->ob_size == b->ob_size
+		if (Py_Size(a) == Py_Size(b)
 		    && (a->ob_sval[0] == b->ob_sval[0]
-			&& memcmp(a->ob_sval, b->ob_sval, a->ob_size) == 0)) {
+			&& memcmp(a->ob_sval, b->ob_sval, Py_Size(a)) == 0)) {
 			result = Py_True;
 		} else {
 			result = Py_False;
 		}
 		goto out;
 	}
-	len_a = a->ob_size; len_b = b->ob_size;
+	len_a = Py_Size(a); len_b = Py_Size(b);
 	min_len = (len_a < len_b) ? len_a : len_b;
 	if (min_len > 0) {
 		c = Py_CHARMASK(*a->ob_sval) - Py_CHARMASK(*b->ob_sval);
@@ -1170,9 +1170,9 @@
 {
 	PyStringObject *a = (PyStringObject*) o1;
 	PyStringObject *b = (PyStringObject*) o2;
-        return a->ob_size == b->ob_size
+        return Py_Size(a) == Py_Size(b)
           && *a->ob_sval == *b->ob_sval
-          && memcmp(a->ob_sval, b->ob_sval, a->ob_size) == 0;
+          && memcmp(a->ob_sval, b->ob_sval, Py_Size(a)) == 0;
 }
 
 static long
@@ -1184,12 +1184,12 @@
 
 	if (a->ob_shash != -1)
 		return a->ob_shash;
-	len = a->ob_size;
+	len = Py_Size(a);
 	p = (unsigned char *) a->ob_sval;
 	x = *p << 7;
 	while (--len >= 0)
 		x = (1000003*x) ^ *p++;
-	x ^= a->ob_size;
+	x ^= Py_Size(a);
 	if (x == -1)
 		x = -2;
 	a->ob_shash = x;
@@ -1242,7 +1242,7 @@
 	else {
 		PyErr_Format(PyExc_TypeError,
 			     "string indices must be integers, not %.200s",
-			     item->ob_type->tp_name);
+			     Py_Type(item)->tp_name);
 		return NULL;
 	}
 }
@@ -1256,7 +1256,7 @@
 		return -1;
 	}
 	*ptr = (void *)self->ob_sval;
-	return self->ob_size;
+	return Py_Size(self);
 }
 
 static Py_ssize_t
@@ -1271,7 +1271,7 @@
 string_buffer_getsegcount(PyStringObject *self, Py_ssize_t *lenp)
 {
 	if ( lenp )
-		*lenp = self->ob_size;
+		*lenp = Py_Size(self);
 	return 1;
 }
 
@@ -1284,7 +1284,7 @@
 		return -1;
 	}
 	*ptr = self->ob_sval;
-	return self->ob_size;
+	return Py_Size(self);
 }
 
 static PySequenceMethods string_as_sequence = {
@@ -1373,7 +1373,7 @@
 	count++; }
 
 /* Always force the list to the expected size. */
-#define FIX_PREALLOC_SIZE(list) ((PyListObject *)list)->ob_size = count
+#define FIX_PREALLOC_SIZE(list) Py_Size(list) = count
 
 #define SKIP_SPACE(s, i, len)    { while (i<len &&  isspace(Py_CHARMASK(s[i]))) i++; }
 #define SKIP_NONSPACE(s, i, len) { while (i<len && !isspace(Py_CHARMASK(s[i]))) i++; }
@@ -1788,7 +1788,7 @@
 			PyErr_Format(PyExc_TypeError,
 				     "sequence item %zd: expected string,"
 				     " %.80s found",
-				     i, item->ob_type->tp_name);
+				     i, Py_Type(item)->tp_name);
 			Py_DECREF(seq);
 			return NULL;
 		}
@@ -3248,7 +3248,7 @@
         PyErr_Format(PyExc_TypeError,
                      "encoder did not return a string/unicode object "
                      "(type=%.400s)",
-                     v->ob_type->tp_name);
+                     Py_Type(v)->tp_name);
         Py_DECREF(v);
         return NULL;
     }
@@ -3285,7 +3285,7 @@
         PyErr_Format(PyExc_TypeError,
                      "decoder did not return a string/unicode object "
                      "(type=%.400s)",
-                     v->ob_type->tp_name);
+                     Py_Type(v)->tp_name);
         Py_DECREF(v);
         return NULL;
     }
@@ -3843,7 +3843,7 @@
 static PyObject *
 string_getnewargs(PyStringObject *v)
 {
-	return Py_BuildValue("(s#)", v->ob_sval, v->ob_size);
+	return Py_BuildValue("(s#)", v->ob_sval, Py_Size(v));
 }
 
 
@@ -3972,8 +3972,7 @@
 
 
 PyTypeObject PyBaseString_Type = {
-	PyObject_HEAD_INIT(&PyType_Type)
-	0,
+	PyVarObject_HEAD_INIT(&PyType_Type, 0)
 	"basestring",
 	0,
 	0,
@@ -4021,8 +4020,7 @@
 If the argument is a string, the return value is the same object.");
 
 PyTypeObject PyString_Type = {
-	PyObject_HEAD_INIT(&PyType_Type)
-	0,
+	PyVarObject_HEAD_INIT(&PyType_Type, 0)
 	"str",
 	sizeof(PyStringObject),
 	sizeof(char),
@@ -4108,7 +4106,7 @@
 	register PyObject *v;
 	register PyStringObject *sv;
 	v = *pv;
-	if (!PyString_Check(v) || v->ob_refcnt != 1 || newsize < 0 ||
+	if (!PyString_Check(v) || Py_Refcnt(v) != 1 || newsize < 0 ||
 	    PyString_CHECK_INTERNED(v)) {
 		*pv = 0;
 		Py_DECREF(v);
@@ -4127,7 +4125,7 @@
 	}
 	_Py_NewReference(*pv);
 	sv = (PyStringObject *) *pv;
-	sv->ob_size = newsize;
+	Py_Size(sv) = newsize;
 	sv->ob_sval[newsize] = '\0';
 	sv->ob_shash = -1;	/* invalidate cached hash value */
 	return 0;
@@ -4175,7 +4173,7 @@
 	x = PyFloat_AsDouble(v);
 	if (x == -1.0 && PyErr_Occurred()) {
 		PyErr_Format(PyExc_TypeError, "float argument required, "
-			     "not %.200s", v->ob_type->tp_name);
+			     "not %.200s", Py_Type(v)->tp_name);
 		return -1;
 	}
 	if (prec < 0)
@@ -4249,15 +4247,15 @@
 	switch (type) {
 	case 'd':
 	case 'u':
-		result = val->ob_type->tp_str(val);
+		result = Py_Type(val)->tp_str(val);
 		break;
 	case 'o':
-		result = val->ob_type->tp_as_number->nb_oct(val);
+		result = Py_Type(val)->tp_as_number->nb_oct(val);
 		break;
 	case 'x':
 	case 'X':
 		numnondigits = 2;
-		result = val->ob_type->tp_as_number->nb_hex(val);
+		result = Py_Type(val)->tp_as_number->nb_hex(val);
 		break;
 	default:
 		assert(!"'type' not in [duoxX]");
@@ -4272,7 +4270,7 @@
 	}
 
 	/* To modify the string in-place, there can only be one reference. */
-	if (result->ob_refcnt != 1) {
+	if (Py_Refcnt(result) != 1) {
 		PyErr_BadInternalCall();
 		return NULL;
 	}
@@ -4372,7 +4370,7 @@
 	x = PyInt_AsLong(v);
 	if (x == -1 && PyErr_Occurred()) {
 		PyErr_Format(PyExc_TypeError, "int argument required, not %.200s",
-			     v->ob_type->tp_name);
+			     Py_Type(v)->tp_name);
 		return -1;
 	}
 	if (x < 0 && type == 'u') {
@@ -4489,7 +4487,7 @@
 		arglen = -1;
 		argidx = -2;
 	}
-	if (args->ob_type->tp_as_mapping && !PyTuple_Check(args) &&
+	if (Py_Type(args)->tp_as_mapping && !PyTuple_Check(args) &&
 	    !PyObject_TypeCheck(args, &PyBaseString_Type))
 		dict = args;
 	while (--fmtcnt >= 0) {
@@ -4956,7 +4954,7 @@
 	}
 	/* The two references in interned are not counted by refcnt.
 	   The string deallocator will take care of this */
-	s->ob_refcnt -= 2;
+	Py_Refcnt(s) -= 2;
 	PyString_CHECK_INTERNED(s) = SSTATE_INTERNED_MORTAL;
 }
 
@@ -5023,12 +5021,12 @@
 			/* XXX Shouldn't happen */
 			break;
 		case SSTATE_INTERNED_IMMORTAL:
-			s->ob_refcnt += 1;
-			immortal_size += s->ob_size;
+			Py_Refcnt(s) += 1;
+			immortal_size += Py_Size(s);
 			break;
 		case SSTATE_INTERNED_MORTAL:
-			s->ob_refcnt += 2;
-			mortal_size += s->ob_size;
+			Py_Refcnt(s) += 2;
+			mortal_size += Py_Size(s);
 			break;
 		default:
 			Py_FatalError("Inconsistent interned string state.");