Change the parser and compiler to use PyMalloc.
Only the files implementing processes that will request memory
allocations small enough for PyMalloc to be a win have been
changed, which are:-
- Python/compile.c
- Parser/acceler.c
- Parser/node.c
- Parser/parsetok.c
This augments the aggressive overallocation strategy implemented by
Tim Peters in PyNode_AddChild() [Parser/node.c], in reducing the
impact of platform malloc()/realloc()/free() corner case behaviour.
Such corner cases are known to be triggered by test_longexp and
test_import.
Jeremy Hylton, in accepting this patch, recommended this as a
bugfix candidate for 2.2. While the changes to Python/compile.c
and Parser/node.c backport easily (and could go in), the changes
to Parser/acceler.c and Parser/parsetok.c require other not
insignificant changes as a result of the differences in the memory
APIs between 2.3 and 2.2, which I'm not in a position to work
through at the moment. This is a pity, as the Parser/parsetok.c
changes are the most important after the Parser/node.c changes, due
to the size of the memory requests involved and their frequency.
disaster too, so this change is here to stay. Beefed up the comments
and added some stats Andrew reported. Also a small change to the
macro body, to make it obvious how XXXROUNDUP(0) ends up returning 0.
See SF patch 578297 for context.
Not a bugfix candidate, as the functional changes here have already
been backported to the 2.2 line (this patch just improves clarity).
This gets us closer to consistent Ctrl+C behaviour on NT and Win9x. NT now reliably generates KeyboardInterrupt exceptions for NT when a file IO operation was aborted. Bugfix candidate
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.
children gets large, to avoid severe platform realloc() degeneration
in extreme cases (like test_longexp).
Bugfix candidate.
This was doing extremely timid over-allocation, just rounding up to the
nearest multiple of 3. Now so long as the number of children is <= 128,
it rounds up to a multiple of 4 but via a much faster method. When the
number of children exceeds 128, though, and more space is needed, it
doubles the capacity. This is aggressive over-allocation.
SF patch <http://www.python.org/sf/578297> has Andrew MacIntyre using
PyMalloc in the parser to overcome platform malloc problems in
test_longexp on OS/2 EMX. Jack Jansen notes there that it didn't help
him on the Mac, because the Mac has problems with frequent ever-growing
reallocs, not just with gazillions of teensy mallocs. Win98 has no
visible problems with test_longexp, but I tried boosting the test-case
size and soon got "senseless" MemoryErrors out of it, and soon after
crashed the OS: as I've seen in many other contexts before, while the
Win98 realloc remains zippy in bad cases, it leads to extreme
fragmentation of user address space, to the point that the OS barfs.
I don't yet know whether this fixes Jack's Mac problems, but it does cure
Win98's problems when boosting the test case size. It also speeds
test_longexp in its unaltered state.
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.
This introduces:
- A new operator // that means floor division (the kind of division
where 1/2 is 0).
- The "future division" statement ("from __future__ import division)
which changes the meaning of the / operator to implement "true
division" (where 1/2 is 0.5).
- New overloadable operators __truediv__ and __floordiv__.
- New slots in the PyNumberMethods struct for true and floor division,
new abstract APIs for them, new opcodes, and so on.
I emphasize that without the future division statement, the semantics
of / will remain unchanged until Python 3.0.
Not yet implemented are warnings (default off) when / is used with int
or long arguments.
This has been on display since 7/31 as SF patch #443474.
Flames to /dev/null.
This is really stupid because it cannot be suppressed or altered using
the warning framework; that's because the warning framework is built
on Python interpreter internals, and the parser generator doesn't have
access to any of those (you cannot use anything of type PyObject * in
the parser).
But it's better than nothing, and implementing a proper check for this
appears to require modifying compile.c in a dozen places, for which I
don't have the stamina today. I promise we'll do better in 2.2a2.
At least it tells you the filename and line number (unlike the first
hack I considered :-).
that 'yield' is a keyword. This doesn't help test_generators at all! I
don't know why not. These things do work now (and didn't before this
patch):
1. "from __future__ import generators" now works in a native shell.
2. Similarly "python -i xxx.py" now has generators enabled in the
shell if xxx.py had them enabled.
3. This program (which was my doctest proxy) works fine:
from __future__ import generators
source = """\
def f():
yield 1
"""
exec compile(source, "", "single") in globals()
print type(f())
the yield statement. I figure we have to have this in before I can
release 2.2a1 on Wednesday.
Note: test_generators is currently broken, I'm counting on Tim to fix
this.
#115555.
The error from s_push() on stack overflow was -1, which was passed
through unchanged by push(), but not tested for by push()'s caller --
which only expected positive error codes. Fixed by changing s_push()
to return E_NOMEM on stack overflow. (Not quite the proper error code
either, but I can't be bothered adding a new E_STACKOVERFLOW error
code in all the right places.)
Add definitions of INT_MAX and LONG_MAX to pyport.h.
Remove includes of limits.h and conditional definitions of INT_MAX
and LONG_MAX elsewhere.
This closes SourceForge patch #101659 and bug #115323.
Martin v. Löwis
Jack Jansen
Tim Peters
Andrew MacIntyre
Mark Hammond
Jeremy Hylton
Thomas Heller
Guido van Rossum
Neal Norwitz
Neil Schemenauer
Barry Warsaw
Fred Drake
Vladimir Marangozov