computation as the overflow behavior of signed integers is undefined.
NOTE: This change is smaller compared to 3.2 as much of this cleanup had
already been done. I added the comment that my change in 3.2 added so that the
code would match up. Otherwise this just adds or synchronizes appropriate UL
designations on some constants to be pedantic.
In practice we require compiling everything with -fwrapv which forces overflow
to be defined as twos compliment but this keeps the code cleaner for checkers
or in the case where someone has compiled it without -fwrapv or their
compiler's equivalent. We could work to get rid of the -fwrapv requirement
in 3.4 but that requires more planning.
Found by Clang trunk's Undefined Behavior Sanitizer (UBSan).
Cleanup only - no functionality or hash values change.
computation as the overflow behavior of signed integers is undefined.
NOTE: This change is smaller compared to 3.2 as much of this cleanup had
already been done. I added the comment that my change in 3.2 added so that the
code would match up. Otherwise this just adds or synchronizes appropriate UL
designations on some constants to be pedantic.
In practice we require compiling everything with -fwrapv which forces overflow
to be defined as twos compliment but this keeps the code cleaner for checkers
or in the case where someone has compiled it without -fwrapv or their
compiler's equivalent.
Found by Clang trunk's Undefined Behavior Sanitizer (UBSan).
Cleanup only - no functionality or hash values change.
computation as the overflow behavior of signed integers is undefined.
In practice we require compiling everything with -fwrapv which forces overflow
to be defined as twos compliment but this keeps the code cleaner for checkers
or in the case where someone has compiled it without -fwrapv or their
compiler's equivalent.
Found by Clang trunk's Undefined Behavior Sanitizer (UBSan).
Cleanup only - no functionality or hash values change.
longer required as of Python 2.5+ when the gc_refs changed from an int (4
bytes) to a Py_ssize_t (8 bytes) as the minimum size is 16 bytes.
The use of a 'long double' triggered a warning by Clang trunk's
Undefined-Behavior Sanitizer as on many platforms a long double requires
16-byte alignment but the Python memory allocator only guarantees 8 byte
alignment.
So our code would allocate and use these structures with technically improper
alignment. Though it didn't matter since the 'dummy' field is never used.
This silences that warning.
Spelunking into code history, the double was added in 2001 to force better
alignment on some platforms and changed to a long double in 2002 to appease
Tru64. That issue should no loner be present since the upgrade from int to
Py_ssize_t where the minimum structure size increased to 16 (unless anyone
knows of a platform where ssize_t is 4 bytes?) or 24 bytes depending on if the
build uses 4 or 8 byte pointers.
We can probably get rid of the double and this union hack all together today.
That is a slightly more invasive change that can be left for later.
A more correct non-hacky alternative if any alignment issues are still found
would be to use a compiler specific alignment declaration on the structure and
determine which value to use at configure time.
ASCII/surrogateescape codec is now used, instead of the locale encoding, to
decode the command line arguments. This change fixes inconsistencies with
os.fsencode() and os.fsdecode() because these operating systems announces an
ASCII locale encoding, whereas the ISO-8859-1 encoding is used in practice.
Previously, excessive nesting in expressions would blow the
stack and segfault the interpreter. Now, a hard limit based
on the configured recursion limit and a hardcoded scaling
factor is applied.
... (unsigned long and unsigned int) to avoid an undefined behaviour with
Py_TPFLAGS_TYPE_SUBCLASS ((1 << 31). PyType_GetFlags() result type is now
unsigned too (unsigned long, instead of long).
* Simplify the code: replace 4 steps with one unique step using the
_PyUnicodeWriter API. PyUnicode_Format() has the same design. It avoids to
store intermediate results which require to allocate an array of pointers on
the heap.
* Use the _PyUnicodeWriter API for speed (and its convinient API):
overallocate the buffer to reduce the number of "realloc()"
* Implement "width" and "precision" in Python, don't rely on sprintf(). It
avoids to need of a temporary buffer allocated on the heap: only use a small
buffer allocated in the stack.
* Add _PyUnicodeWriter_WriteCstr() function
* Split PyUnicode_FromFormatV() into two functions: add
unicode_fromformat_arg().
* Inline parse_format_flags(): the format of an argument is now only parsed
once, it's no more needed to have a subfunction.
* Optimize PyUnicode_FromFormatV() for characters between two "%" arguments:
search the next "%" and copy the substring in one chunk, instead of copying
character per character.
sporadic crashes in multi-thread programs when several long deallocator
chains ran concurrently and involved subclasses of built-in container
types.
Note that the trashcan functions are part of the stable ABI, therefore
they have to be kept around for binary compatibility of extensions.
sporadic crashes in multi-thread programs when several long deallocator
chains ran concurrently and involved subclasses of built-in container
types.
Because of this change, a couple extension modules compiled for 3.2.4
(those which use the trashcan mechanism, despite it being undocumented)
will not be loadable by 3.2.3 and earlier. However, extension modules
compiled for 3.2.3 and earlier will be loadable by 3.2.4.
sporadic crashes in multi-thread programs when several long deallocator
chains ran concurrently and involved subclasses of built-in container
types.
Because of this change, a couple extension modules compiled for 3.2.4
(those which use the trashcan mechanism, despite it being undocumented)
will not be loadable by 3.2.3 and earlier. However, extension modules
compiled for 3.2.3 and earlier will be loadable by 3.2.4.
PyImport_ImportModuleLevel() with a 'level' of 0 instead of -1 as the
latter is no longer a valid value.
Also added a versionchanged note for PyImport_ImportModuleLevel() just
in case people don't make the connection between changes to
__import__() and this C function.
Fix also its value on Windows and Linux according to its documentation:
"adjustable" indicates if the clock *can be* adjusted, not if it is or was
adjusted.
In most cases, it is not possible to indicate if a clock is or was adjusted.
* Formatting string, int, float and complex use the _PyUnicodeWriter API. It
avoids a temporary buffer in most cases.
* Add _PyUnicodeWriter_WriteStr() to restore the PyAccu optimization: just
keep a reference to the string if the output is only composed of one string
* Disable overallocation when formatting the last argument of str%args and
str.format(args)
* Overallocation allocates at least 100 characters: add min_length attribute
to the _PyUnicodeWriter structure
* Add new private functions: _PyUnicode_FastCopyCharacters(),
_PyUnicode_FastFill() and _PyUnicode_FromASCII()
The speed up is around 20% in average.
Removed futimens as it is now redundant.
Changed shutil.copystat to use st_atime_ns and st_mtime_ns from os.stat
and ns= parameter to utime--it once again preserves exact metadata on Linux!
Serhiy Storchaka
Christian Heimes
Andrew Svetlov
Gregory P. Smith
Antoine Pitrou
Benjamin Peterson
Victor Stinner
Mark Dickinson
Stefan Krah
Mark Dickinson
Nick Coghlan
Georg Brandl
Armin Ronacher
Ezio Melotti
Jesus Cea
Trent Nelson
Brett Cannon
Martin v. Löwis
David Malcolm
Barry Warsaw
Eli Bendersky
Richard Oudkerk
Larry Hastings