[issue15251] new.code and new.function crashes Python iterpretter
New submission from Jeffrey Harper jeff1.61...@gmail.com: I've attached a script that crashes the Python interpreter. I can get the crash to occur under Windows Vista with this version of Python: C:\tmp\remotec:\Python27\python.exe Python 2.7.1 Stackless 3.1b3 060516 (release27-maint, Jan 1 2011, 13:04:37) [MSC v.1500 32 bit (Intel)] on win32 Also, I got it to segfault under Ubuntu Linux: jharper@ubuntu:~$ uname -a Linux ubuntu 2.6.35-27-generic #48-Ubuntu SMP Tue Feb 22 20:25:29 UTC 2011 i686 GNU/Linux jharper@ubuntu:~$ python Python 2.6.6 (r266:84292, Sep 15 2010, 15:52:39) [GCC 4.4.5] on linux2 Note, when I commented out the line, pprint(code_args), the script generated a SystemError exception instead of crashing. -- components: Library (Lib) files: bug3.py messages: 164652 nosy: jeffdharper priority: normal severity: normal status: open title: new.code and new.function crashes Python iterpretter type: crash versions: Python 2.6, Python 2.7 Added file: http://bugs.python.org/file26257/bug3.py ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15251 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15251] new.code and new.function crashes Python iterpretter
Jeffrey Harper jeff1.61...@gmail.com added the comment: The marshal loads and dumps don't seem to be necessary to reproduce the crash. On both the Windows Vista and Ubuntu Linux systems, the crash still occurred when I replaced: mcopy_code = loads(dumps(code)) with: mcopy_code = code #loads(dumps(code)) -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15251 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue15251] new.code and new.function crashes Python iterpretter
Jeffrey Harper jeff1.61...@gmail.com added the comment: Martin, Thanks for your response. I didn't know it was possible to pass freevars and cellvars to new.code. I think the documentation needs to be updated. The documentation for 2.7.3 located at http://docs.python.org/library/new.html?highlight=new#new.code is as follows: new.code(argcount, nlocals, stacksize, flags, codestring, constants, names, varnames, filename, name, firstlineno, lnotab) After I got your reply to this bug report I did help(new.code) and I see that it includes freevars and cellvars as optional arguments. -- assignee: - docs@python components: +Documentation -Library (Lib) nosy: +docs@python ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue15251 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue11244] Negative tuple elements produce inefficient code.
New submission from Jeffrey Harper jhar...@yapdc.com: In Python 3.2, a tuple like (1,-2,3) will not be optimized into a constants at compile time. The tuple is built at run-time. Earlier versions of Python optimized these tuples at compile time. Here's an example program. # test.py from dis import dis def x(): return (1,2,3) def y(): return (1,-2,3) print (dis x:) dis(x) print() print(dis y:) dis(y) The compiler in 3.2rc3 produces code for function y() that builds the tuple at run-time while the tuple in x() is optimized at compile time. C:\tmpc:\python32\python --version Python 3.2rc3 C:\tmpc:\python32\python test.py dis x: 3 0 LOAD_CONST 4 ((1, 2, 3)) 3 RETURN_VALUE dis y: 4 0 LOAD_CONST 1 (1) 3 LOAD_CONST 4 (-2) 6 LOAD_CONST 3 (3) 9 BUILD_TUPLE 3 12 RETURN_VALUE However, under 3.1.3, the tuples in both functions are optimized at compile time. C:\tmpc:\python31\python test.py dis x: 3 0 LOAD_CONST 4 ((1, 2, 3)) 3 RETURN_VALUE dis y: 4 0 LOAD_CONST 4 ((1, -2, 3)) 3 RETURN_VALUE Although the compiled code produced 3.2rc3 is correct, it is much slower than the code generated by 3.1.3. -- messages: 128795 nosy: jdharper priority: normal severity: normal status: open title: Negative tuple elements produce inefficient code. type: performance versions: Python 3.2 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue11244 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue11244] Negative tuple elements produce inefficient code.
Jeffrey Harper jhar...@yapdc.com added the comment:
I have also determined that negative elements interfere with the frozenset
optimization described in issue6690. http://bugs.python.org/issue6690.
Here's an example program:
# test.py
from dis import dis
def x(var): return var in {1,2,3} # Note curly braces. These are sets.
def y(var): return var in {1,-2,3}
print (dis x:)
dis(x)
print()
print(dis y:)
dis(y)
Running this produces:
C:\tmpc:\Python32\python.exe test.py
dis x:
3 0 LOAD_FAST0 (var)
3 LOAD_CONST 4 (frozenset({1, 2, 3}))
6 COMPARE_OP 6 (in)
9 RETURN_VALUE
dis y:
4 0 LOAD_FAST0 (var)
3 LOAD_CONST 1 (1)
6 LOAD_CONST 4 (-2)
9 LOAD_CONST 3 (3)
12 BUILD_SET3
15 COMPARE_OP 6 (in)
18 RETURN_VALUE
--
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[issue11244] Negative tuple elements produce inefficient code.
Jeffrey Harper jhar...@yapdc.com added the comment: I think r82043 may also explain why 3.1.3 can fold the expression 2 * -3 into -6 while 3.2rc3 cannot. # test.py from dis import dis def y(): 2 * -3 print(dis y:) dis(y) C:\tmpc:\Python32\python.exe --version Python 3.2rc3 C:\tmpc:\Python32\python.exe test.py dis y: 3 0 LOAD_CONST 1 (2) 3 LOAD_CONST 3 (-3) 6 BINARY_MULTIPLY 7 POP_TOP 8 LOAD_CONST 0 (None) 11 RETURN_VALUE C:\tmpc:\Python31\python.exe --version Python 3.1.3 C:\tmpc:\Python31\python.exe test.py dis y: 3 0 LOAD_CONST 3 (-6) 3 POP_TOP 4 LOAD_CONST 0 (None) 7 RETURN_VALUE -- ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue11244 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue11244] Negative tuple elements produce inefficient code.
Jeffrey Harper jhar...@yapdc.com added the comment:
Here's a patch against the version of test_peepholer.py in 3.2rc3. It verifies
that expressions like the following are optimized:
3*-4
(1,-2,3)
a in {1,-2,3)
--
keywords: +patch
Added file: http://bugs.python.org/file20787/test_peepholer.patch
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[issue11099] Bytes pickled with 3.1 not unpickled with 2.7 correctly
New submission from Jeffrey Harper jhar...@yapdc.com:
When a bytes object is pickled with 3.1 and then unpickled with 2.7, the
results are incorrect. The example below shows that pickling
b'abcdefg' in 3.1 and then unpickling in 2.7 produces the string
'[97L, 98L, 99L, 100L, 101L, 102L, 103L]'
The unpickling operation should return 'abcdefg'.
C:\decompyle\jtestc:\Python31\python
Python 3.1.3 (r313:86834, Nov 27 2010, 18:30:53) [MSC v.1500 32 bit (Intel)] on
win32
Type help, copyright, credits or license for more information.
file = open('test.pkl', 'wb')
import pickle
pickle.dump(b'abcdefg', file, 0)
exit()
C:\decompyle\jtestc:\python27\python
Python 2.7 Stackless 3.1b3 060516 (release27-maint, Jul 22 2010, 18:58:18) [MSC
v.1500 32 bit (Intel)] on win32
Type help, copyright, credits or license for more information.
file = open('test.pkl', 'rb')
import pickle
pickle.load(file)
'[97L, 98L, 99L, 100L, 101L, 102L, 103L]'
--
components: Library (Lib), Unicode
messages: 127735
nosy: jdharper
priority: normal
severity: normal
status: open
title: Bytes pickled with 3.1 not unpickled with 2.7 correctly
versions: Python 2.7, Python 3.1
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