Commit Graph

9 Commits

Author SHA1 Message Date
Miss Islington (bot) 392520bd78 bpo-33312: Fix clang ubsan out of bounds warnings in dict. (GH-6537) (GH-6543)
Fix clang ubsan (undefined behavior sanitizer) warnings in dictobject.c by
adjusting how the internal struct _dictkeysobject shared keys structure is
declared.

This remains ABI compatible.  We get rid of the union at the end of the
struct being used for conveinence to avoid typecasting in favor of char[]
variable length array at the end of a struct. This is known to clang to be
used for variable sized objects and will not cause an undefined behavior
problem.  Similarly, char arrays do not have strict aliasing undefined
behavior when cast.

PEP-007 does not currently list variable length arrays (VLAs) as allowed
in our subset of C99.  If this turns out to be a problem, the fix to this is
to change the char `dk_indices[]` into `dk_indices[1]` and restore the
three size computation subtractions this change removes:
  `- Py_MEMBER_SIZE(PyDictKeysObject, dk_indices)`

If this works as is I'll make a separate PR to update PEP-007.
(cherry picked from commit 397f1b28c4)
2018-04-20 10:06:21 -07:00
INADA Naoki 778928b0c7 bpo-29304: Simplify dict lookup functions (GH-2407)
* remove hashpos parameter from lookdict functions.
* remove many duplicated code from lookdict functions.
2017-08-03 23:45:15 +09:00
INADA Naoki ba6097734d Issue #28818: Simplify lookdict functions 2016-12-07 20:41:42 +09:00
Victor Stinner 611b0fa94c Add _PyDict_CheckConsistency()
Issue #28127: Add a function to check that a dictionary remains consistent
after any change.

By default, tables are not checked, only basic attributes. Define DEBUG_PYDICT
(ex: gcc -D DEBUG_PYDICT) to also check dictionary "content".
2016-09-14 15:02:01 +02:00
Benjamin Peterson 3c569295d6 do not worry about 64-bit dict sizes on 32-bit platforms 2016-09-08 13:16:41 -07:00
Benjamin Peterson 186122ead2 access dk_indices through a union 2016-09-08 12:20:12 -07:00
Victor Stinner a4348cc1be Add documentation to the dict implementation
Issue #27350.
2016-09-08 12:01:25 -07:00
Victor Stinner 742da040db Implement compact dict
Issue #27350: `dict` implementation is changed like PyPy. It is more compact
and preserves insertion order.

_PyDict_Dummy() function has been removed.

Disable test_gdb: python-gdb.py is not updated yet to the new structure of
compact dictionaries (issue #28023).

Patch written by INADA Naoki.
2016-09-07 17:40:12 -07:00
Eric Snow 47db71756d Issue #16991: Add a C implementation of collections.OrderedDict. 2015-05-29 22:21:39 -06:00