Le dim. 5 avr. 2020 à 04:02, Skip Montanaro <skip.montan...@gmail.com> a écrit :
> The command is
>
> % PYTHONTRACEMALLOC=5 ./python ./Tools/scripts/run_tests.py -R
> 5:50:reflog.txt test_rattlesnake
> (...)
> FWIW, the register branch of my CPython fork:
>
> https://github.com/smontanaro/cpython/tree/register
gdb traceback:
(gdb) where
(...)
#2 0x000000000056671d in fatal_error_exit (status=-1) at
Python/pylifecycle.c:2183
(...)
#8 0x000000000047d61e in PyObject_Free (ptr=0x7d3e40
<_Py_FalseStruct>) at Objects/obmalloc.c:709
#9 0x0000000000498a9b in object_dealloc (self=False) at
Objects/typeobject.c:3824
#10 0x000000000047c5aa in _Py_Dealloc (op=False) at Objects/object.c:2206
#11 0x00000000005f771c in _Py_DECREF (filename=0x741e7d
"./Modules/_io/iobase.c", lineno=275, op=False) at
./Include/object.h:425
#12 0x00000000005f7f16 in iobase_finalize (self=<_io.TextIOWrapper at
remote 0x7fffeab2a6e0>) at ./Modules/_io/iobase.c:275
#13 0x0000000000477755 in PyObject_CallFinalizer
(self=<_io.TextIOWrapper at remote 0x7fffeab2a6e0>) at
Objects/object.c:193
#14 0x00000000004777ea in PyObject_CallFinalizerFromDealloc
(self=<_io.TextIOWrapper at remote 0x7fffeab2a6e0>) at
Objects/object.c:211
#15 0x00000000005f7fd8 in _PyIOBase_finalize (self=<_io.TextIOWrapper
at remote 0x7fffeab2a6e0>) at ./Modules/_io/iobase.c:319
#16 0x0000000000609533 in textiowrapper_dealloc (self=0x7fffeab2a6e0)
at ./Modules/_io/textio.c:1433
(...)
#48 0x0000000000595fa7 in delete_garbage (tstate=0x82dc80,
gcstate=0x82c648, collectable=0x7fffffffd2c0, old=0x82c690) at
Modules/gcmodule.c:1005
#49 0x00000000005965c8 in collect (tstate=0x82dc80, generation=2,
n_collected=0x0, n_uncollectable=0x0, nofail=1) at
Modules/gcmodule.c:1275
#50 0x00000000005980e7 in _PyGC_CollectNoFail () at Modules/gcmodule.c:2099
#51 0x0000000000546da8 in _PyImport_Cleanup (tstate=0x82dc80) at
Python/import.c:633
#52 0x0000000000564f89 in Py_FinalizeEx () at Python/pylifecycle.c:1416
#53 0x000000000041ed1b in Py_RunMain () at Modules/main.c:634
#54 0x000000000041ed90 in pymain_main (args=0x7fffffffd500) at
Modules/main.c:662
#55 0x000000000041ee0a in Py_BytesMain (argc=6, argv=0x7fffffffd628)
at Modules/main.c:686
#56 0x000000000041d786 in main (argc=6, argv=0x7fffffffd628) at
./Programs/python.c:16
(gdb) p *res
$6 = {
ob_refcnt = 0,
ob_type = 0x7d3ca0 <PyBool_Type>
}
(gdb) p *(PyLongObject*)res
$7 = {
ob_base = {
ob_base = {
ob_refcnt = 0,
ob_type = 0x7d3ca0 <PyBool_Type>
},
ob_size = 0
},
ob_digit = {0}
}
(gdb) p res == ((PyObject *) &_Py_FalseStruct)
$8 = 1
Py_FinalizeEx() cleans up all modules with _PyImport_Cleanup(). When
Python destroys a _io.TextIOWrapper instance, Py_False is destroyed...
Py_False must never me deallocated: it's statically allocated.
Py_False reference counter should not decrease to 0.
It seems like your Python changes use Py_False "somewhere" without
Py_INCREF(Py_False).
--
It seems like you are working on a register-based bytecode, cool. I
recall that you told me something like that ;-)
It seems like executing the register-based bytecode of the following
function is enough to steal one reference to False (use False without
INCREF):
def _long_block(s, b):
if s > b:
return s
return b
Maybe it's COMPARE_OP_REG() which calls SETLOCAL(dst, False).
Maybe it's JUMP_IF_FALSE_REG() which has suspicious code: DECREF
without clearing GETLOCAL(src).
PyObject *cond = GETLOCAL(src);
..
Py_DECREF(cond);
Maybe SETLOCAL(src, NULL); is need somewhere.
Maybe it's something else.
Replacing stack-based bytecode with register-based bytecode requires
to rethink the lifetime of registers... I had a hard time to fix my
old "registervm" project to fix the register lifetime: I added
CLEAR_REG bytecode to explicitly clear a register. Using a stack, all
"CLEAR_REG" operation are implicit. You have to make them explicit.
Hopefully, a compiler can easily reuse registers and remove most
CLEAR_REG.
--
My old project (2012, OMG, I'm getting old!):
https://faster-cpython.readthedocs.io/registervm.html
https://hg.python.org/sandbox/registervm/file/tip/REGISTERVM.txt
Victor
--
Night gathers, and now my watch begins. It shall not end until my death.
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