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#5057: the peepholer no longer optimizes subscription on unicode literals (e.g. u"foo"[0]) in order to produce compatible pyc files between narrow and wide builds.

This commit is contained in:
Ezio Melotti 2012-11-05 00:03:21 +02:00
parent 51c374dede
commit c18cc0edff
3 changed files with 18 additions and 26 deletions
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13
Lib/test/test_peepholer.py
View File

@ -138,21 +138,22 @@ class TestTranforms(unittest.TestCase):
self.assertIn('(1000)', asm)
def test_binary_subscr_on_unicode(self):
# valid code get optimized
# unicode strings don't get optimized
asm = dis_single('u"foo"[0]')
self.assertIn("(u'f')", asm)
self.assertNotIn('BINARY_SUBSCR', asm)
self.assertNotIn("(u'f')", asm)
self.assertIn('BINARY_SUBSCR', asm)
asm = dis_single('u"\u0061\uffff"[1]')
self.assertIn("(u'\\uffff')", asm)
self.assertNotIn('BINARY_SUBSCR', asm)
self.assertNotIn("(u'\\uffff')", asm)
self.assertIn('BINARY_SUBSCR', asm)
# invalid code doesn't get optimized
# out of range
asm = dis_single('u"fuu"[10]')
self.assertIn('BINARY_SUBSCR', asm)
# non-BMP char (see #5057)
asm = dis_single('u"\U00012345"[0]')
self.assertIn('BINARY_SUBSCR', asm)
asm = dis_single('u"\U00012345abcdef"[3]')
self.assertIn('BINARY_SUBSCR', asm)
def test_folding_of_unaryops_on_constants(self):

4
Misc/NEWS
View File

@ -9,6 +9,10 @@ What's New in Python 2.7.4
Core and Builtins
-----------------
- Issue #5057: the peepholer no longer optimize subscription on unicode
literals (e.g. u'foo'[0]) in order to produce compatible pyc files between
narrow and wide builds.
- Issue #8401: assigning an int to a bytearray slice (e.g. b[3:4] = 5) now
raises an error.

27
Python/peephole.c
View File

@ -128,27 +128,14 @@ fold_binops_on_constants(unsigned char *codestr, PyObject *consts)
newconst = PyNumber_Subtract(v, w);
break;
case BINARY_SUBSCR:
newconst = PyObject_GetItem(v, w);
/* #5057: if v is unicode, there might be differences between
wide and narrow builds in cases like u'\U00012345'[0].
Wide builds will return a non-BMP char, whereas narrow builds
will return a surrogate. In both the cases skip the
optimization in order to produce compatible pycs.
*/
#ifdef Py_USING_UNICODE
if (newconst != NULL &&
PyUnicode_Check(v) && PyUnicode_Check(newconst)) {
Py_UNICODE ch = PyUnicode_AS_UNICODE(newconst)[0];
#ifdef Py_UNICODE_WIDE
if (ch > 0xFFFF) {
#else
if (ch >= 0xD800 && ch <= 0xDFFF) {
#endif
Py_DECREF(newconst);
return 0;
}
}
#endif
wide and narrow builds in cases like '\U00012345'[0] or
'\U00012345abcdef'[3], so it's better to skip the optimization
in order to produce compatible pycs.
*/
if (PyUnicode_Check(v))
return 0;
newconst = PyObject_GetItem(v, w);
break;
case BINARY_LSHIFT:
newconst = PyNumber_Lshift(v, w);