diff -r 2f0716009132 Include/bytes_methods.h
--- a/Include/bytes_methods.h	Tue Jul 12 18:24:25 2016 -0400
+++ b/Include/bytes_methods.h	Wed Jul 13 14:36:51 2016 +0800
@@ -33,6 +33,10 @@
 /* The maketrans() static method. */
 extern PyObject* _Py_bytes_maketrans(Py_buffer *frm, Py_buffer *to);
 
+extern PyObject *_Py_bytes_repr(const char *str, Py_ssize_t len, const char *name,
+                                const char *quote_prefix, const char *quote_postfix,
+                                int smartquotes);
+
 /* Shared __doc__ strings. */
 extern const char _Py_isspace__doc__[];
 extern const char _Py_isalpha__doc__[];
diff -r 2f0716009132 Objects/bytearrayobject.c
--- a/Objects/bytearrayobject.c	Tue Jul 12 18:24:25 2016 -0400
+++ b/Objects/bytearrayobject.c	Wed Jul 13 14:36:51 2016 +0800
@@ -882,89 +882,13 @@
     return -1;
 }
 
-/* Mostly copied from string_repr, but without the
-   "smart quote" functionality. */
 static PyObject *
 bytearray_repr(PyByteArrayObject *self)
 {
-    const char *quote_prefix = "bytearray(b";
-    const char *quote_postfix = ")";
-    Py_ssize_t length = Py_SIZE(self);
-    /* 15 == strlen(quote_prefix) + 2 + strlen(quote_postfix) + 1 */
-    size_t newsize;
-    PyObject *v;
-    Py_ssize_t i;
-    char *bytes;
-    char c;
-    char *p;
-    int quote;
-    char *test, *start;
-    char *buffer;
-
-    if (length > (PY_SSIZE_T_MAX - 15) / 4) {
-        PyErr_SetString(PyExc_OverflowError,
-            "bytearray object is too large to make repr");
-        return NULL;
-    }
-
-    newsize = 15 + length * 4;
-    buffer = PyObject_Malloc(newsize);
-    if (buffer == NULL) {
-        PyErr_NoMemory();
-        return NULL;
-    }
-
-    /* Figure out which quote to use; single is preferred */
-    quote = '\'';
-    start = PyByteArray_AS_STRING(self);
-    for (test = start; test < start+length; ++test) {
-        if (*test == '"') {
-            quote = '\''; /* back to single */
-            break;
-        }
-        else if (*test == '\'')
-            quote = '"';
-    }
-
-    p = buffer;
-    while (*quote_prefix)
-        *p++ = *quote_prefix++;
-    *p++ = quote;
-
-    bytes = PyByteArray_AS_STRING(self);
-    for (i = 0; i < length; i++) {
-        /* There's at least enough room for a hex escape
-           and a closing quote. */
-        assert(newsize - (p - buffer) >= 5);
-        c = bytes[i];
-        if (c == '\'' || c == '\\')
-            *p++ = '\\', *p++ = c;
-        else if (c == '\t')
-            *p++ = '\\', *p++ = 't';
-        else if (c == '\n')
-            *p++ = '\\', *p++ = 'n';
-        else if (c == '\r')
-            *p++ = '\\', *p++ = 'r';
-        else if (c == 0)
-            *p++ = '\\', *p++ = 'x', *p++ = '0', *p++ = '0';
-        else if (c < ' ' || c >= 0x7f) {
-            *p++ = '\\';
-            *p++ = 'x';
-            *p++ = Py_hexdigits[(c & 0xf0) >> 4];
-            *p++ = Py_hexdigits[c & 0xf];
-        }
-        else
-            *p++ = c;
-    }
-    assert(newsize - (p - buffer) >= 1);
-    *p++ = quote;
-    while (*quote_postfix) {
-       *p++ = *quote_postfix++;
-    }
-
-    v = PyUnicode_DecodeASCII(buffer, p - buffer, NULL);
-    PyObject_Free(buffer);
-    return v;
+    return _Py_bytes_repr(PyByteArray_AS_STRING(self),
+                          PyByteArray_GET_SIZE(self),
+                          Py_TYPE(self)->tp_name,
+                          "bytearray(b", ")", 1);
 }
 
 static PyObject *
diff -r 2f0716009132 Objects/bytes_methods.c
--- a/Objects/bytes_methods.c	Tue Jul 12 18:24:25 2016 -0400
+++ b/Objects/bytes_methods.c	Wed Jul 13 14:36:51 2016 +0800
@@ -812,3 +812,81 @@
 "Pad a numeric string B with zeros on the left, to fill a field\n"
 "of the specified width.  B is never truncated.");
 
+
+PyObject *
+_Py_bytes_repr(const char *str, Py_ssize_t len, const char *name,
+               const char *quote_prefix, const char *quote_postfix,
+               int smartquotes)
+{
+    Py_ssize_t i;
+    Py_ssize_t newsize, squotes, dquotes;
+    unsigned char *s, *p, quote;
+    PyObject *v;
+
+    squotes = dquotes = 0;
+    newsize = strlen(quote_prefix) + 2 + strlen(quote_postfix);  /* 2 quotes */
+    s = (unsigned char *)str;
+    for (i = 0; i < len; i++) {
+        Py_ssize_t incr = 1;
+        switch(s[i]) {
+        case '\'': squotes++; break;
+        case '"':  dquotes++; break;
+        case '\\': case '\t': case '\n': case '\r':
+            incr = 2; break;
+        default:
+            if (s[i] < ' ' || s[i] >= 0x7f)
+                incr = 4;
+        }
+        if (newsize > PY_SSIZE_T_MAX - incr)
+            goto overflow;
+        newsize += incr;
+    }
+    quote = '\'';
+    if (smartquotes && squotes && !dquotes)
+        quote = '"';
+    if (squotes && quote == '\'') {
+        if (newsize > PY_SSIZE_T_MAX - squotes)
+            goto overflow;
+        newsize += squotes;
+    }
+
+    v = PyUnicode_New(newsize, 127);
+    if (v == NULL)
+        return NULL;
+    p = PyUnicode_1BYTE_DATA(v);
+
+    while (*quote_prefix)
+        *p++ = *quote_prefix++;
+    *p++ = quote;
+    for (i = 0; i < len; i++) {
+        unsigned char c = (unsigned char)str[i];
+        if (c == quote || c == '\\')
+            *p++ = '\\', *p++ = c;
+        else if (c == '\t')
+            *p++ = '\\', *p++ = 't';
+        else if (c == '\n')
+            *p++ = '\\', *p++ = 'n';
+        else if (c == '\r')
+            *p++ = '\\', *p++ = 'r';
+        else if (c < ' ' || c >= 0x7f) {
+            *p++ = '\\';
+            *p++ = 'x';
+            *p++ = Py_hexdigits[(c & 0xf0) >> 4];
+            *p++ = Py_hexdigits[c & 0xf];
+        }
+        else
+            *p++ = c;
+    }
+    *p++ = quote;
+    while (*quote_postfix)
+        *p++ = *quote_postfix++;
+    assert(_PyUnicode_CheckConsistency(v, 1));
+    return v;
+
+ overflow:
+    PyErr_Format(PyExc_OverflowError,
+                 "%.100s object is too large to make repr",
+                 name);
+    return NULL;
+
+}
diff -r 2f0716009132 Objects/bytesobject.c
--- a/Objects/bytesobject.c	Tue Jul 12 18:24:25 2016 -0400
+++ b/Objects/bytesobject.c	Wed Jul 13 14:36:51 2016 +0800
@@ -1291,74 +1291,8 @@
 PyObject *
 PyBytes_Repr(PyObject *obj, int smartquotes)
 {
-    PyBytesObject* op = (PyBytesObject*) obj;
-    Py_ssize_t i, length = Py_SIZE(op);
-    Py_ssize_t newsize, squotes, dquotes;
-    PyObject *v;
-    unsigned char quote, *s, *p;
-
-    /* Compute size of output string */
-    squotes = dquotes = 0;
-    newsize = 3; /* b'' */
-    s = (unsigned char*)op->ob_sval;
-    for (i = 0; i < length; i++) {
-        Py_ssize_t incr = 1;
-        switch(s[i]) {
-        case '\'': squotes++; break;
-        case '"':  dquotes++; break;
-        case '\\': case '\t': case '\n': case '\r':
-            incr = 2; break; /* \C */
-        default:
-            if (s[i] < ' ' || s[i] >= 0x7f)
-                incr = 4; /* \xHH */
-        }
-        if (newsize > PY_SSIZE_T_MAX - incr)
-            goto overflow;
-        newsize += incr;
-    }
-    quote = '\'';
-    if (smartquotes && squotes && !dquotes)
-        quote = '"';
-    if (squotes && quote == '\'') {
-        if (newsize > PY_SSIZE_T_MAX - squotes)
-            goto overflow;
-        newsize += squotes;
-    }
-
-    v = PyUnicode_New(newsize, 127);
-    if (v == NULL) {
-        return NULL;
-    }
-    p = PyUnicode_1BYTE_DATA(v);
-
-    *p++ = 'b', *p++ = quote;
-    for (i = 0; i < length; i++) {
-        unsigned char c = op->ob_sval[i];
-        if (c == quote || c == '\\')
-            *p++ = '\\', *p++ = c;
-        else if (c == '\t')
-            *p++ = '\\', *p++ = 't';
-        else if (c == '\n')
-            *p++ = '\\', *p++ = 'n';
-        else if (c == '\r')
-            *p++ = '\\', *p++ = 'r';
-        else if (c < ' ' || c >= 0x7f) {
-            *p++ = '\\';
-            *p++ = 'x';
-            *p++ = Py_hexdigits[(c & 0xf0) >> 4];
-            *p++ = Py_hexdigits[c & 0xf];
-        }
-        else
-            *p++ = c;
-    }
-    *p++ = quote;
-    assert(_PyUnicode_CheckConsistency(v, 1));
-    return v;
-
-  overflow:
-    PyErr_SetString(PyExc_OverflowError,
-                    "bytes object is too large to make repr");
-    return NULL;
+    return _Py_bytes_repr(PyBytes_AS_STRING(obj), PyBytes_GET_SIZE(obj),
+                          Py_TYPE(obj)->tp_name, "b", "", smartquotes);
 }
 
 static PyObject *