version of PySlice_GetIndicesEx"):
> OK. Michael, if you want to check in indices(), go ahead.
Then I did what was needed, but didn't check it in. Here it is.
listsort. If the former calls itself recursively, they're a waste of
time, since it's called on a random permutation of a random subset of
elements. OTOH, for exactly the same reason, they're an immeasurably
small waste of time (the odds of finding exploitable order in a random
permutation are ~= 0, so the special-case loops looking for order give
up quickly). The point is more for conceptual clarity.
Also changed some "assert comments" into real asserts; when this code
was first written, Python.h didn't supply assert.h.
introduced, list.sort() was rewritten to use only the "< or not <?"
distinction. After rich comparisons were introduced, docompare() was
fiddled to translate a Py_LT Boolean result into the old "-1 for <,
0 for ==, 1 for >" flavor of outcome, and the sorting code was left
alone. This left things more obscure than they should be, and turns
out it also cost measurable cycles.
So: The old CMPERROR novelty is gone. docompare() is renamed to islt(),
and now has the same return conditinos as PyObject_RichCompareBool. The
SETK macro is renamed to ISLT, and is even weirder than before (don't
complain unless you want to maintain the sort code <wink>).
Overall, this yields a 1-2% speedup in the usual (no explicit function
passed to list.sort()) case when sorting arrays of floats (as sortperf.py
does). The boost is higher for arrays of ints.
The staticforward define was needed to support certain broken C
compilers (notably SCO ODT 3.0, perhaps early AIX as well) botched the
static keyword when it was used with a forward declaration of a static
initialized structure. Standard C allows the forward declaration with
static, and we've decided to stop catering to broken C compilers. (In
fact, we expect that the compilers are all fixed eight years later.)
I'm leaving staticforward and statichere defined in object.h as
static. This is only for backwards compatibility with C extensions
that might still use it.
XXX I haven't updated the documentation.
PyType_Ready() because the tp_iternext slot is set (fortunately,
because using the tp_iternext implementation for the the next()
implementation is buggy). Also changed the allocation order in
enum_next() so that the underlying iterator is only moved ahead when
we have successfully allocated the result tuple and index.
di_dict field when the end of the list is reached. Also make the
error ("dictionary changed size during iteration") a sticky state.
Also remove the next() method -- one is supplied automatically by
PyType_Ready() because the tp_iternext slot is set. That's a good
thing, because the implementation given here was buggy (it never
raised StopIteration).
object references (it_seq for seqiterobject, it_callable and
it_sentinel for calliterobject) when the end of the list is reached.
Also remove the next() methods -- one is supplied automatically by
PyType_Ready() because the tp_iternext slot is set. That's a good
thing, because the implementation given here was buggy (it never
raised StopIteration).
it_seq field when the end of the list is reached.
Also remove the next() method -- one is supplied automatically by
PyType_Ready() because the tp_iternext slot is set. That's a good
thing, because the implementation given here was buggy (it never
raised StopIteration).
If the object is an ExtensionClass, for example, the slot is not even
defined. So we must check that the type has the slot (implied by
HAVE_CLASS) before calling tp_init().
explicit comparison function case: use PyObject_Call instead of
PyEval_CallObject. Same thing in context, but gives a 2.4% overall
speedup when sorting a list of ints via list.sort(__builtin__.cmp).
MSDN sample programs use it, apparently in error. The correct name
is WIN32_LEAN_AND_MEAN. After switching to the correct name, in two
cases more was needed because the code actually relied on things that
disappear when WIN32_LEAN_AND_MEAN is defined.
arg tuple. This was suggested on c.l.py but afraid I can't find the msg
again for proper attribution. For
list.sort(cmp)
where list is a list of random ints, and cmp is __builtin__.cmp, this
yields an overall 50-60% speedup on my Win2K box. Of course this is a
best case, because the overhead of calling cmp relative to the cost of
actually comparing two ints is at an extreme. Nevertheless it's huge
bang for the buck. An additionak 20-30% can be bought by making the arg
tuple an immortal static (avoiding all but "the first" PyTuple_New), but
that's tricky to make correct since docompare needs to be reentrant. So
this picks the cherry and leaves the pits for Fred <wink>.
Note that this makes no difference to the
list.sort()
case; an arg tuple gets built only if the user specifies an explicit
sort function.
helper macros to something saner, and used them appropriately in other
files too, to reduce #ifdef blocks.
classobject.c, instance_dealloc(): One of my worst Python Memories is
trying to fix this routine a few years ago when COUNT_ALLOCS was defined
but Py_TRACE_REFS wasn't. The special-build code here is way too
complicated. Now it's much simpler. Difference: in a Py_TRACE_REFS
build, the instance is no longer in the doubly-linked list of live
objects while its __del__ method is executing, and that may be visible
via sys.getobjects() called from a __del__ method. Tough -- the object
is presumed dead while its __del__ is executing anyway, and not calling
_Py_NewReference() at the start allows enormous code simplification.
typeobject.c, call_finalizer(): The special-build instance_dealloc()
pain apparently spread to here too via cut-'n-paste, and this is much
simpler now too. In addition, I didn't understand why this routine
was calling _PyObject_GC_TRACK() after a resurrection, since there's no
plausible way _PyObject_GC_UNTRACK() could have been called on the
object by this point. I suspect it was left over from pasting the
instance_delloc() code. Instead asserted that the object is still
tracked. Caution: I suspect we don't have a test that actually
exercises the subtype_dealloc() __del__-resurrected-me code.
more trivial lexical helper macros so that uses of these guys expand
to nothing at all when they're not enabled. This should help sub-
standard compilers that can't do a good job of optimizing away the
previous "(void)0" expressions.
Py_DECREF: There's only one definition of this now. Yay! That
was that last one in the family defined multiple times in an #ifdef
maze.
Py_FatalError(): Changed the char* signature to const char*.
_Py_NegativeRefcount(): New helper function for the Py_REF_DEBUG
expansion of Py_DECREF. Calling an external function cuts down on
the volume of generated code. The previous inline expansion of abort()
didn't work as intended on Windows (the program often kept going, and
the error msg scrolled off the screen unseen). _Py_NegativeRefcount
calls Py_FatalError instead, which captures our best knowledge of
how to abort effectively across platforms.
Repair segfaults and infinite loops in COUNT_ALLOCS builds in the
presence of new-style (heap-allocated) classes/types.
Bugfix candidate. I'll backport this to 2.2. It's irrelevant in 2.1.
that have taken me "too long" to reverse-engineer over the years.
Vastly reduced the nesting level and redundancy of #ifdef-ery.
Took a light stab at repairing comments that are no longer true.
sys_gettotalrefcount(): Changed to enable under Py_REF_DEBUG.
It was enabled under Py_TRACE_REFS, which was much heavier than
necessary. sys.gettotalrefcount() is now available in a
Py_REF_DEBUG-only build.
mechanism is no longer evil: it no longer plays dangerous games with
the type pointer or refcounts, and objects in extension modules can play
along too without needing to edit the core first.
Rewrote all the comments to explain this, and (I hope) give clear
guidance to extension authors who do want to play along. Documented
all the functions. Added more asserts (it may no longer be evil, but
it's still dangerous <0.9 wink>). Rearranged the generated code to
make it clearer, and to tolerate either the presence or absence of a
semicolon after the macros. Rewrote _PyTrash_destroy_chain() to call
tp_dealloc directly; it was doing a Py_DECREF again, and that has all
sorts of obscure distorting effects in non-release builds (Py_DECREF
was already called on the object!). Removed Christian's little "embedded
change log" comments -- that's what checkin messages are for, and since
it was impossible to correlate the comments with the code that changed,
I found them merely distracting.
In a fresh interpreter, type.mro(tuple) would segfault, because
PyType_Ready() isn't called for tuple yet. To fix, call
PyType_Ready(type) if type->tp_dict is NULL.
These built-in functions are replaced by their (now callable) type:
slice()
buffer()
and these types can also be called (but have no built-in named
function named after them)
classobj (type name used to be "class")
code
function
instance
instancemethod (type name used to be "instance method")
The module "new" has been replaced with a small backward compatibility
placeholder in Python.
A large portion of the patch simply removes the new module from
various platform-specific build recipes. The following binary Mac
project files still have references to it:
Mac/Build/PythonCore.mcp
Mac/Build/PythonStandSmall.mcp
Mac/Build/PythonStandalone.mcp
[I've tweaked the code layout and the doc strings here and there, and
added a comment to types.py about StringTypes vs. basestring. --Guido]
gotten from a weak reference to NULL instead of to None. This caused
the following assert() to fail (but only in 2.2 in the debug build --
I have to find a better test case). Will backport.
optional attribute, only clear the exception when the internal getattr
operation raised AttributeError. Many places in this file already had
that policy; but just as many didn't, and there didn't seem to be any
rhyme or reason to it. Be consistently cautious.
Question: should I backport this? On the one hand it's a bugfix. On
the other hand it's a change in behavior. Certain forms of buggy or
just weird code would work in the past but raise an exception under
the new rules; e.g. if you define a __getattr__ method that raises a
non-AttributeError exception.
473985. Through a subtle rearrangement of some members in the etype
struct (!), mapping methods are now preferred over sequence methods,
which is necessary to support str.__getitem__("hello", slice(4)) etc.
[ 400998 ] experimental support for extended slicing on lists
somewhat spruced up and better tested than it was when I wrote it.
Includes docs & tests. The whatsnew section needs expanding, and arrays
should support extended slices -- later.
discovered that subtype_traverse must traverse the type if it is a
heap type, because otherwise some cycles involving a type and its
instance would not be collected. Simplest example:
while 1:
class C(object): pass
C.ref = C()
This program grows without bounds before this fix. (It grows ever
slower since it spends ever more time in the collector.)
Simply adding the right visit() call to subtype_traverse() revealed
other problems. With MvL's help we re-learned that type_clear()
doesn't have to clear *all* references, only the ones that may not be
cleared by other means. Careful analysis (see comments in the code)
revealed that only tp_mro needs to be cleared. (The previous checkin
to this file adds a test for tp_mro==NULL to _PyType_Lookup() that's
essential to prevent crashes due to tp_mro being NULL when
subtype_dealloc() tries to look for a __del__ method.) The same kind
of analysis also revealed that subtype_clear() doesn't need to clear
the instance dict.
With this fix, a useful property of the collector is once again
guaranteed: a single gc.collect() call will clear out all garbage.
(It didn't always before, which put us on the track of this bug.)
Will backport to 2.2.
about the test case, slot_nb_power gets called on behalf of its second
argument, but with a non-None modulus it wouldn't check this, and
believes it is called on behalf of its first argument. Fix this
properly, and get rid of the code in _PyType_Lookup() that tries to
call _PyType_Ready(). But do leave a check for a NULL tp_mro there,
because this can still legitimately occur.
I'll fix this in 2.2.x too.
While I was at it, I added a tp_clear handler and changed the
tp_dealloc handler to use the clear_slots helper for the tp_clear
handler.
Also tightened the rules for slot names: they must now be proper
identifiers (ignoring the dirty little fact that <ctype.h> is locale
sensitive).
Also set mp->flags = READONLY for the __weakref__ pseudo-slot.
Most of this is a 2.2 bugfix candidate; I'll apply it there myself.
Change the module constructor (module_init) to have the signature
__init__(name:str, doc=None); this prevents the call from type_new()
to succeed. While we're at it, prevent repeated calling of
module_init for the same module from leaking the dict, changing the
semantics so that __dict__ is only initialized if NULL.
Also adding a unittest, test_module.py.
This is an incompatibility with 2.2, if anybody was instantiating the
module class before, their argument list was probably empty; so this
can't be backported to 2.2.x.
In the past, an object's tp_compare could return any value. In 2.2
the docs were tightened to require it to return -1, 0 or 1; and -1 for
an error.
We now issue a warning if the value is not in this range. When an
exception is raised, we allow -1 or -2 as return value, since -2 will
the recommended return value for errors in the future. (Eventually
tp_compare will also be allowed to return +2, to indicate
NotImplemented; but that can only be implemented once we know all
extensions return a value in [-2...1]. Or perhaps it will require the
type to set a flag bit.)
I haven't decided yet whether to backport this to 2.2.x. The patch
applies fine. But is it fair to start warning in 2.2.2 about code
that worked flawlessly in 2.2.1?
for 'str' and 'unicode', and can be used instead of
types.StringTypes, e.g. to test whether something is "a string":
isinstance(x, string) is True for Unicode and 8-bit strings. This
is an abstract base class and cannot be instantiated directly.
A MemoryError is now raised when the list cannot be created.
There is a test, but as the comment says, it really only
works for 32 bit systems. I don't know how to improve
the test for other systems (ie, 64 bit or systems
where the data size != addressable size,
e.g. 64 bit data, but 48 bit addressable memory)
returned a proxy for __class__ whose __bases__ was also a proxy. The
merge_class_dict() helper for dir() assumed incorrectly that __bases__
would always be a tuple and used the in-line tuple API on the proxy.
I will backport this to 2.2 as well.
handlers were both set, but were not compatible. This change uses only the
tp_getattro handler with a more "modern" approach.
This fixes SF bug #551285.
don't understand how this function works, also beefed up the docs. The
most common usage error is of this form (often spread out across gotos):
if (_PyString_Resize(&s, n) < 0) {
Py_DECREF(s);
s = NULL;
goto outtahere;
}
The error is that if _PyString_Resize runs out of memory, it automatically
decrefs the input string object s (which also deallocates it, since its
refcount must be 1 upon entry), and sets s to NULL. So if the "if"
branch ever triggers, it's an error to call Py_DECREF(s): s is already
NULL! A correct way to write the above is the simpler (and intended)
if (_PyString_Resize(&s, n) < 0)
goto outtahere;
Bugfix candidate.
This implements ideas from Marc-Andre, Martin, Guido and me on Python-Dev.
"Short" Unicode strings are encoded into a "big enough" stack buffer,
then exactly as much string space as they turn out to need is allocated
at the end. This should have speed benefits akin to Martin's "measure
once, allocate once" strategy, but without needing a distinct measuring
pass.
"Long" Unicode strings allocate as much heap space as they could possibly
need (4 x # Unicode chars), and do a realloc at the end to return the
untouched excess. Since the overallocation is likely to be substantial,
this shouldn't burden the platform realloc with unusably small excess
blocks.
Also simplified uses of the PyString_xyz functions. Also added a release-
build check that 4*size doesn't overflow a C int. Sooner or later, that's
going to happen.
left and right type were of the same type and not classic instances.
This shortcut is dangerous for proxy types, because it means that
coerce(Proxy(1), Proxy(2.1)) leaves Proxy(1) unchanged rather than
turning it into Proxy(1.0).
In an ever-so-slight change of semantics, I now only take the shortcut
when the left and right types are of the same type and don't have the
CHECKTYPES feature. It so happens that classic instances have this
flag, so the shortcut is still skipped in this case (i.e. nothing
changes for classic instances). Proxies also have this flag set
(otherwise implementing numeric operations on proxies would become
nightmarish) and this means that the shortcut is also skipped there,
as desired. It so happens that int, long and float also have this
flag set; that means that e.g. coerce(1, 1) will now invoke
int_coerce(). This is fine: int_coerce() can deal with this, and I'm
not worried about the performance; int_coerce() is only invoked when
the user explicitly calls coerce(), which should be rarer than rare.
This fixes the problem that Barry reported on python-dev:
>>> 23000 .__class__ = bool
crashes in the deallocator. This was because int inherited tp_free
from object, which uses the default allocator.
2.2. Bugfix candidate.
states can be for this function, and ensure that only AttributeErrors
are masked. Any other exception raised via the equivalent of
getattr(cls, '__bases__') should be propagated up.
abstract_issubclass(): If abstract_get_bases() returns NULL, we must
call PyErr_Occurred() to see if an exception is being propagated, and
return -1 or 0 as appropriate. This is the specific fix for a problem
whereby if getattr(derived, '__bases__') raised an exception, an
"undetected error" would occur (under a debug build). This nasty
situation was uncovered when writing a security proxy extension type
for the Zope3 project, where the security proxy raised a Forbidden
exception on getattr of __bases__.
PyObject_IsInstance(), PyObject_IsSubclass(): After both calls to
abstract_get_bases(), where we're setting the TypeError if the return
value is NULL, we must first check to see if an exception occurred,
and /not/ mask an existing exception.
Neil Schemenauer should double check that these changes don't break
his ExtensionClass examples (there aren't any test cases for those
examples and abstract_get_bases() was added by him in response to
problems with ExtensionClass). Neil, please add test cases if
possible!
I belive this is a bug fix candidate for Python 2.2.2.
http://www.python.org/sf/444708
This adds the optional argument for str.strip
to unicode.strip too and makes it possible
to call str.strip with a unicode argument
and unicode.strip with a str argument.
+ Continued looping until n bytes in the buffer have been filled, not
just when n bytes have been read from the file. This repairs the
bug that f.readlines() only sucked up the first 8192 bytes of the file
on Windows when universal newlines was enabled and f was opened in
U mode (see Python-Dev -- this was the ultimate cause of the
test_inspect.py failure).
+ Changed prototye to take a char* buffer (void* doesn't make much sense).
+ Squashed size_t vs int mismatches (in particular, besides the unsigned
vs signed distinction, size_t may be larger than int).
+ Gets out under all error conditions now (it's possible for fread() to
suffer an error even if it returns a number larger than 0 -- any
"short read" is an error or EOF condition).
+ Rearranged and simplified declarations.
pointers is a signed type. Changing "allocated" to a signed int makes
undetected overflow more likely, but there was no overflow detection
before either.
PyFrame_FastToLocals() and PyFrame_LocalsToFast() had a return if
f_nlocals was 0. I think this was a holdover from the pre 2.1 days
when regular locals were the only kind of local variables.
The change makes it possible to use a free variable in eval or exec if
it the variable is also used elsewhere in the same block, which is
what the documentation says.
consistency checks, enabled only in a debug (Py_DEBUG) build. Note that
this never gets called automatically unless PYMALLOC_DEBUG is #define'd
too, and the envar PYTHONMALLOCSTATS exists.
Change type_get_doc (the get function for __doc__) to look in tp_dict
more often, and if it finds a descriptor in tp_dict, to call it (with
a NULL instance). This means you can add a __doc__ descriptor to a
new-style class that returns instance docs when called on an instance,
and class docs when called on a class -- or the same docs in either
case, but lazily computed.
I'll also check this into the 2.2 maintenance branch.
PyNumber_InPlaceMultiply insisted on calling sq_inplace_repeat if it
existed, even if nb_inplace_multiply also existed and the arguments
weren't right for sq_inplace_repeat. Change this to only use
sq_inplace_repeat if nb_inplace_multiply isn't defined.
Bugfix candidate.
Add a method zfill to str, unicode and UserString and change
Lib/string.py accordingly.
This activates the zfill version in unicodeobject.c that was
commented out and implements the same in stringobject.c. It also
adds the test for unicode support in Lib/string.py back in and
uses repr() instead() of str() (as it was before Lib/string.py 1.62)
Complex numbers implement divmod() and //, neither of which makes one
lick of sense. Unfortunately this is documented, so I'm adding a
deprecation warning now, so we can delete this silliness, oh, around
2005 or so.
Bugfix candidate (At least for 2.2.2, I think.)
Highlights: import and friends will understand any of \r, \n and \r\n
as end of line. Python file input will do the same if you use mode 'U'.
Everything can be disabled by configuring with --without-universal-newlines.
See PEP278 for details.
Added code to call this when PYMALLOC_DEBUG is enabled, and envar
PYTHONMALLOCSTATS is set, whenever a new arena is obtained and once
late in the Python shutdown process.
Put a bound on the number of frameobjects that can live in the
frameobject free_list.
Am also backporting to 2.2. I don't intend to backport to 2.1 (too
much work -- lots of cyclic structures leak there, and the GC API).
Add optional arg to string methods strip(), lstrip(), rstrip().
The optional arg specifies characters to delete.
Also for UserString.
Still to do:
- Misc/NEWS
- LaTeX docs (I did the docstrings though)
- Unicode methods, and Unicode support in the string methods.
_PyObject_DebugMalloc: explicitly cast PyObject_Malloc's result to the
target pointer type.
_PyObject_DebugDumpStats: change decl of arena_alignment from unsigned
int to unsigned long.
This is for the 2.3 release only (it's new code).
most of the work. In particular, if the underlying realloc is able to
grow the memory block in place, great (this routine used to do a fresh
malloc + memcpy every time a block grew). BTW, I'm not so keen here on
avoiding possible quadratic-time realloc patterns as I am on making
the debug pymalloc more invisible (the more it uses memory "just like"
the underlying allocator, the better the chance that a suspected memory
corruption bug won't vanish when the debug malloc is turned on).
PyMem_{Del, DEL} doesn't work yet (compilation problems).
pyport.h: _PyMem_EXTRA is gone.
pmem.h: Repaired comments. PyMem_{Malloc, MALLOC} and
PyMem_{Realloc, REALLOC} now make the same x-platform guarantees when
asking for 0 bytes, and when passing a NULL pointer to the latter.
object.c: PyMem_{Malloc, Realloc} just call their macro versions
now, since the latter take care of the x-platform 0 and NULL stuff
by themselves now.
pypcre.c, grow_stack(): So sue me. On two lines, this called
PyMem_RESIZE to grow a "const" area. It's not legit to realloc a
const area, so the compiler warned given the new expansion of
PyMem_RESIZE. It would have gotten the same warning before if it
had used PyMem_Resize() instead; the older macro version, but not the
function version, silently cast away the constness. IMO that was a wrong
thing to do, and the docs say the macro versions of PyMem_xyz are
deprecated anyway. If somebody else is resizing const areas with the
macro spelling, they'll get a warning when they recompile now too.
The bug report pointed out a bogosity in the comment block explaining
thread safety for arena management. Repaired that comment, repaired a
couple others while I was at it, and added an assert.
_PyMalloc_DebugRealloc: If this needed to get more memory, but couldn't,
it erroneously freed the original memory. Repaired that.
This is for 2.3 only (unless we decide to backport the new pymalloc).
open_the_file: Some (not all) flavors of Windows set errno to EINVAL
when passed a syntactically invalid filename. Python turned that into an
incomprehensible complaint about the mode string. Fixed by special-casing
MSVC.
when PyType_Ready() was called, if ob_type was found to be NULL, it
was always set to &PyType_Type; now it is set to base->ob_type,
where base is tp_base, defaulting to &PyObject_Type.
- PyType_Ready() accidentally did not inherit tp_is_gc; now it does.
Bugfix candidate.
runtime multiplications and divisions, via the scheme developed with
Vladimir Marangozov on Python-Dev. The pool_header struct loses its
capacity member, but gains nextoffset and maxnextoffset members; this
still leaves it at 32 bytes on a 32-bit box (it has to be padded to a
multiple of 8 bytes).
speeds up __getitem__ and __setitem__ in subclasses of built-in
sequences.
It's much revised because I took the opportunity to refactor the code
somewhat (moving a large section of duplicated code to a helper
function) and added comments to a series of functions.
what these do given a 0 size argument. This is so that when pymalloc
is enabled, we don't need to wrap pymalloc calls in goofy little
routines special-casing 0. Note that it's virtually impossible to meet
the doc's promise that malloc(0) will never return NULL; this makes a
best effort, but not an insane effort. The code does promise that
realloc(not-NULL, 0) will never return NULL (malloc(0) is much harder).
_PyMalloc_Realloc: Changed to take over all requests for 0 bytes, and
rearranged to be a little quicker in expected cases.
All over the place: when resorting to the platform allocator, call
free/malloc/realloc directly, without indirecting thru macros. This
should avoid needing a nightmarish pile of #ifdef-ery if PYMALLOC_DEBUG
is changed so that pymalloc takes over all Py(Mem, Object} memory
operations (which would add useful debugging info to PyMem_xyz
allocations too).
PEP 285. Everything described in the PEP is here, and there is even
some documentation. I had to fix 12 unit tests; all but one of these
were printing Boolean outcomes that changed from 0/1 to False/True.
(The exception is test_unicode.py, which did a type(x) == type(y)
style comparison. I could've fixed that with a single line using
issubtype(x, type(y)), but instead chose to be explicit about those
places where a bool is expected.
Still to do: perhaps more documentation; change standard library
modules to return False/True from predicates.
possible pool states. I think it's much clearer now.
Added a new long overdue block-management overview comment block.
I believe the comments are in good shape now.
Added two comments about possible small optimizations (one getting rid
of runtime multiplications at the cost of a new pool_header member; the
other getting rid of runtime divisions and the pool_header capacity
member, at the cost of a static const vector of 32 uints).
This displays stats about the # of arenas, pools, blocks and bytes, to
stderr, both used and reserved but unused.
CAUTION: Because PYMALLOC_DEBUG is on, the debug malloc routine adds
16 bytes to each request. This makes each block appear two size classes
higher than it would be if PYMALLOC_DEBUG weren't on.
So far, playing with this confirms the obvious: there's a lot of activity
in the "small dict" size class, but nothing in the core makes any use of
the 8-byte or 16-byte classes.
the code so that the most frequent cases come first. Added comments.
Found a hidden assumption that a pool contains room for at least two
blocks, and added an assert to catch a violation if it ever happens in
a place where that matters. Gave the normal "I allocated this block"
case a longer basic block to work with before it has to do its first
branch (via breaking apart an embedded assignment in an "if", and
hoisting common code out of both branches).
address obtained from system malloc/realloc without holding the GIL.
When the vector of arena base addresses has to grow, the old vector is
deliberately leaked. This makes "stale" x-thread references safe.
arenas and narenas are also declared volatile, and changed in an order
that prevents a thread from picking up a value of narenas too large
for the value of arenas it sees.
Added more asserts.
Fixed an old inaccurate comment.
Added a comment explaining why it's safe to call pymalloc free/realloc
with an address obtained from system malloc/realloc even when arenas is
still NULL (this is obscure, since the ADDRESS_IN_RANGE macro
appears <wink> to index into arenas).
this. But added an overflow check just in case there is.
Got rid of the ushort macro. It wasn't used anymore (it was only used
in the no-longer-exists off_t macro), and there's no plausible use for it.
waste the first pool if malloc happens to return a pool-aligned address.
This means the number of pools per arena can now vary by 1. Unfortunately,
the code counted up from 0 to a presumed constant number of pools. So
changed the increasing "watermark" counter to a decreasing "nfreepools"
counter instead, and fiddled various stuff accordingly. This also allowed
getting rid of two more macros.
Also changed the code to align the first address to a pool boundary
instead of a page boundary. These are two parallel sets of macro #defines
that happen to be identical now, but the page macros are in theory more
restrictive (bigger), and there's simply no reason I can see that it
wasn't aligning to the less restrictive pool size all along (the code
only relies on pool alignment).
Hmm. The "page size" macros aren't used for anything *except* defining
the pool size macros, and the comments claim the latter isn't necessary.
So this has the feel of a layer of indirection that doesn't serve a
purpose; should probably get rid of the page macros now.
are called without the GIL. It's incredibly unlikely to fail, but I can't
make this bulletproof without either adding a lock for exclusion, or
giving up on growing the arena base-address vector (it would be safe if
this were a static array).
+ A new scheme for determining whether an address belongs to a pymalloc
arena. This should be 100% reliable. The poolp->pooladdr and
poolp->magic members are gone. A new poolp->arenaindex member takes
their place. Note that the pool header overhead doesn't actually
shrink, though, since the header is padded to a multiple of 8 bytes.
+ _PyMalloc_Free and _PyMalloc_Realloc should now be safe to call for
any legit address, whether obtained from a _PyMalloc function or from
the system malloc/realloc. It should even be safe to call
_PyMalloc_Free when *not* holding the GIL, provided that the passed-in
address was obtained from system malloc/realloc. Since this is
accomplished without any locks, you better believe the code is subtle.
I hope it's sufficiently commented.
+ The above implies we don't need the new PyMalloc_{New, NewVar, Del}
API anymore, and could switch back to PyObject_XXX without breaking
existing code mixing PyObject_XXX with PyMem_{Del, DEL, Free, FREE}.
Nothing is done here about that yet, and I'd like to see this new
code exercised more first.
+ The small object threshhold is boosted to 256 (the max). We should
play with that some more, but the old 64 was way too small for 2.3.
+ Getting a new arena is now done via new function new_arena().
+ Removed some unused macros, and squashed out some macros that were
used only once to define other macros.
+ Arenas are no longer linked together. A new vector of arena base
addresses had to be created anyway to make address classification
bulletproof.
+ A lot of the patch size is an illusion: given the way address
classification works now, it was more convenient to switch the
sense of the prime "if" tests in the realloc and free functions,
so the "if" and "else" blocks got swapped.
+ Assorted minor code, comment and whitespace cleanup.
Back to the Windows installer <wink>.
The fix makes it possible to call PyObject_GC_UnTrack() more than once
on the same object, and then move the PyObject_GC_UnTrack() call to
*before* the trashcan code is invoked.
BUGFIX CANDIDATE!
descriptor, as used for the tp_methods slot of a type. These new flag
bits are both optional, and mutually exclusive. Most methods will not
use either. These flags are used to create special method types which
exist in the same namespace as normal methods without having to use
tedious construction code to insert the new special method objects in
the type's tp_dict after PyType_Ready() has been called.
If METH_CLASS is specified, the method will represent a class method
like that returned by the classmethod() built-in.
If METH_STATIC is specified, the method will represent a static method
like that returned by the staticmethod() built-in.
These flags may not be used in the PyMethodDef table for modules since
these special method types are not meaningful in that case; a
ValueError will be raised if these flags are found in that context.
Martin v. Löwis
Skip Montanaro
Jeremy Hylton
Michael W. Hudson
Tim Peters
Guido van Rossum
Raymond Hettinger
Neal Norwitz
Thomas Heller
Marc-André Lemburg
Barry Warsaw
Walter Dörwald
Fred Drake
Jack Jansen
Neil Schemenauer