[Python-Dev] Is core dump always a bug? Advice requested (original) (raw)

Greg Ewing greg at cosc.canterbury.ac.nz
Tue May 11 23:27:29 EDT 2004

"Fred L. Drake, Jr." <fdrake at acm.org>:

I don't see any reason to think them equivalent; we don't need to determine that the code will execute to completion, only that the bytecodes can be decoded without error.

If arbitrary branching patterns are allowed, then in order to ensure absence of stack overflow/underflow, etc., it will be necessary to do things like proving that certain loops can't execute more than a certain number of times. This smells halting-problem-complete to me.

It would be possible to prove that certain classes of bytecode sequence are valid, and reject all others. But I suspect that would reject a large number of valid-but-hard-to-prove sequences that bytecode hackers would find "interesting".

Greg Ewing, Computer Science Dept, +--------------------------------------+ University of Canterbury, | A citizen of NewZealandCorp, a | Christchurch, New Zealand | wholly-owned subsidiary of USA Inc. | greg at cosc.canterbury.ac.nz +--------------------------------------+

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