[Python-Dev] troubling math bug under IRIX 6.5
Sjoerd Mullender
sjoerd@oratrix.nl
Thu, 15 Feb 2001 09:42:35 +0100
I have compiler version 7.2.1.3m om my O2 and 7.2.1 on the server.
It does indeed sound like a compiler problem, so maybe it's time to do
an upgrade...
On Wed, Feb 14 2001 Flying Cougar Burnette wrote:
>
> 'uname -a' tells me I'm running plain old 6.5 on my R10k O2 with
> version 7.3.1.1m of the sgi compiler. Which version of the compiler
> do you have? That might be the real culprit here. in fact...
>
> I just hopped onto a co-worker's machine that has version 7.3.1.2m of
> the compiler, remade everything, and the problem is gone.
>
> I think we can chalk this up to a compiler bug and take no further
> action. Thanks for listening...
>
>
> Sjoerd Mullender writes:
> | As an extra datapoint:
> |
> | I just tried this (4 * math.exp(-0.5)) on my SGI O2 and on our SGI
> | file server with the current CVS version of Python, compiled with -O.
> | I don't get a crash.
> |
> | I am running IRIX 6.5.10m on the O2 and 6.5.2m on the server. What
> | version are you running?
> |
> | On Tue, Feb 13 2001 Flying Cougar Burnette wrote:
> |
> | > Tim Peters writes:
> | > |
> | > | > now neither does. shall I turn opts back on and try a few more
> | > | > cases?
> | > |
> | > | Yes, please, one more:
> | > |
> | > | 4.0 * 3.1
> | > |
> | > | Or, if that works, go back to the failing
> | > |
> | > | 4.0 * math.exp(-0.5)
> | >
> | > both of these work, but changing the 4.0 to an integer 4 produces the
> | > bus error. so it is definitely a conversion to double/float thats
> | > the problem.
> | >
> | > |
> | > | In any failing case, can you jump into a debubber and get a stack trace?
> | >
> | > sure. I've included an entire dbx session at the end of this mail.
> | >
> | > |
> | > | Do you happen to have
> | > |
> | > | WANT_SIGFPE_HANDLER
> | > |
> | > | #define'd when you compile Python on this platform? If so, it complicates
> | > | the code a lot. I wonder about that because you got a "bus error", and when
> | > | WANT_SIGFPE_HANDLER is #defined we get a whole pile of ugly setjmp/longjmp
> | > | code that doesn't show up on my box.
> | >
> | > a peek at config.h shows the WANT_SIGFPE_HANDLER define commented
> | > out. should I turn it on and see what happens?
> | >
> | >
> | > |
> | > | Another tack, as a temporary workaround: try disabling optimization only
> | > | for Objects/floatobject.c. That will probably fix the problem, and if so
> | > | that's enough of a workaround to get you unstuck while pursuing these other
> | > | irritations.
> | >
> | > this one works just fine. workarounds aren't a problem for me right
> | > now since I'm in no hurry to get this version in use here. I'm just
> | > trying to help debug this version for irix users in general.
> | >
> | >
> | > ------------%< snip %<----------------------%< snip %<------------
> | >
> | > (tommy@mace)/u0/tommy/pycvs/python/dist/src$ dbx python
> | > dbx version 7.3 65959_Jul11 patchSG0003841 Jul 11 2000 02:29:30
> | > Executable /usr/u0/tommy/pycvs/python/dist/src/python
> | > (dbx) run
> | > Process 563746 (python) started
> | > Python 2.1a2 (#6, Feb 13 2001, 17:43:32) [C] on irix6
> | > Type "copyright", "credits" or "license" for more information.
> | > >>> 3 * 4.0
> | > 12.0
> | > >>> import math
> | > >>> 4 * math.exp(-.5)
> | > Process 563746 (python) stopped on signal SIGBUS: Bus error (default) at [float_mul:383 +0x4,0x1004c158]
> | > 383 CONVERT_TO_DOUBLE(v, a);
> | > (dbx) l
> | > >* 383 CONVERT_TO_DOUBLE(v, a);
> | > 384 CONVERT_TO_DOUBLE(w, b);
> | > 385 PyFPE_START_PROTECT("multiply", return 0)
> | > 386 a = a * b;
> | > 387 PyFPE_END_PROTECT(a)
> | > 388 return PyFloat_FromDouble(a);
> | > 389 }
> | > 390
> | > 391 static PyObject *
> | > 392 float_div(PyObject *v, PyObject *w)
> | > (dbx) t
> | > > 0 float_mul(0x100b69fc, 0x10116788, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Objects/floatobject.c":383, 0x1004c158]
> | > 1 binary_op1(0x100b69fc, 0x10116788, 0x0, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Objects/abstract.c":337, 0x1003ac5c]
> | > 2 binary_op(0x100b69fc, 0x10116788, 0x8, 0x0, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Objects/abstract.c":373, 0x1003ae70]
> | > 3 PyNumber_Multiply(0x100b69fc, 0x10116788, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Objects/abstract.c":544, 0x1003b5a4]
> | > 4 eval_code2(0x1012c688, 0x0, 0xffffffec, 0x0, 0x0, 0x0, 0x0, 0x0) ["/usr/u0/tommy/pycvs/python/dist/src/Python/ceval.c":896, 0x10034a54]
> | > 5 PyEval_EvalCode(0x100b69fc, 0x10116788, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/ceval.c":336, 0x10031768]
> | > 6 run_node(0x100f88c0, 0x10116788, 0x0, 0x0, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/pythonrun.c":931, 0x10040444]
> | > 7 PyRun_InteractiveOne(0x0, 0x100b1878, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/pythonrun.c":540, 0x1003f1f0]
> | > 8 PyRun_InteractiveLoop(0xfb4a398, 0x100b1878, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/pythonrun.c":486, 0x1003ef84]
> | > 9 PyRun_AnyFileEx(0xfb4a398, 0x100b1878, 0x0, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Python/pythonrun.c":461, 0x1003eeac]
> | > 10 Py_Main(0x1, 0x0, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Modules/main.c":292, 0x1000bba4]
> | > 11 main(0x100b69fc, 0x10116788, 0x8, 0x100a1318, 0x10050000, 0x10116788, 0x100a1318, 0x100a1290) ["/usr/u0/tommy/pycvs/python/dist/src/Modules/python.c":10, 0x1000b7bc]
> | > More (n if no)?y
> | > 12 __start() ["/xlv55/kudzu-apr12/work/irix/lib/libc/libc_n32_M4/csu/crt1text.s":177, 0x1000b558]
> | > (dbx)
> | >
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> | >
> |
> | -- Sjoerd Mullender <sjoerd.mullender@oratrix.com>
>
-- Sjoerd Mullender <sjoerd.mullender@oratrix.com>