[Python-Dev] troubling math bug under IRIX 6.5
Flying Cougar Burnette
tommy@ilm.com
Wed, 14 Feb 2001 09:57:24 -0800 (PST)
'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>