From: Pip Cet <pipcet@gmail.com>
To: eggert@cs.ucla.edu
Cc: andrewjmoreton@gmail.com, 32463@debbugs.gnu.org
Subject: bug#32463: 27.0.50; (logior -1) => 4611686018427387903
Date: Sun, 19 Aug 2018 10:48:19 +0000 [thread overview]
Message-ID: <CAOqdjBd0JdtjPnK2Z=gfd_zD3SiYktwBuVcBPR322zy5NZkPWw@mail.gmail.com> (raw)
In-Reply-To: <5230a57b-5896-606d-f157-2e547710b6e8@cs.ucla.edu>
On Sat, Aug 18, 2018 at 10:58 PM Paul Eggert <eggert@cs.ucla.edu> wrote:
My bigger concern is memory management, along with integer overflow in size or
> bitcount calculation. Copies are made of bignums when not needed, behavior is
> dicey if memory is exhausted during bignum computation, and I'm afraid C-g will
> have problems when bignums get large.
Even if memory isn't exhausted, creating a bignum larger than 16 GB
(our most-positive-bignum) results in an immediate crash with external
libgmp (Linux, x86_64), and that appears not to be easy to fix without
modifying gmp.
> I don't have a good handle on this stuff
> yet. I have put in some sanity checks (e.g., see check_bignum_size in emacs.c)
> but I suspect more are needed. In particular, Fexpt will need to be careful as
> it is a good way to explode a bignum's size.
That and left shifts are probably the ones to worry about for now.
Creating a large bignum by repeated multiplication will require at
least some intermediate bignums, which need to be allocated and copied
and thus probably alert the user to something going on.
next prev parent reply other threads:[~2018-08-19 10:48 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-17 3:29 bug#32463: 27.0.50; (logior -1) => 4611686018427387903 Katsumi Yamaoka
2018-08-17 5:59 ` Pip Cet
2018-08-17 7:40 ` Katsumi Yamaoka
2018-08-17 9:27 ` Andy Moreton
2018-08-17 11:36 ` Pip Cet
2018-08-17 11:53 ` Pip Cet
2018-08-17 13:27 ` Andy Moreton
2018-08-18 22:43 ` Paul Eggert
2018-08-17 13:24 ` Andy Moreton
2018-08-18 18:48 ` Paul Eggert
2018-08-18 18:59 ` Eli Zaretskii
2018-08-18 19:58 ` Pip Cet
2018-08-18 22:27 ` Paul Eggert
2018-08-19 15:03 ` Eli Zaretskii
2018-08-18 19:59 ` Paul Eggert
2018-08-18 19:45 ` Andy Moreton
2018-08-19 10:43 ` Live System User
2018-08-20 3:02 ` Richard Stallman
2018-08-20 3:47 ` Paul Eggert
2018-08-21 3:37 ` Richard Stallman
2018-08-18 22:56 ` Paul Eggert
2018-08-18 23:17 ` Paul Eggert
2018-08-19 10:34 ` Andy Moreton
2018-08-19 10:48 ` Pip Cet [this message]
2018-08-19 10:59 ` Paul Eggert
2018-08-19 11:32 ` Pip Cet
2018-08-21 9:40 ` Paul Eggert
2018-08-21 10:50 ` Andy Moreton
2018-08-21 14:36 ` Eli Zaretskii
2018-08-21 14:52 ` Andy Moreton
2018-08-21 17:24 ` Paul Eggert
2018-08-19 10:52 ` Paul Eggert
2018-08-22 2:29 ` Paul Eggert
2018-08-22 16:56 ` Tom Tromey
2018-08-22 17:52 ` Paul Eggert
2018-08-22 18:25 ` Eli Zaretskii
2018-08-23 0:28 ` Paul Eggert
2018-08-23 2:39 ` Eli Zaretskii
2018-08-19 18:00 ` Andy Moreton
2018-08-22 2:34 ` Paul Eggert
2018-08-22 23:27 ` Andy Moreton
2018-08-23 14:05 ` Eli Zaretskii
2018-08-22 2:56 ` Paul Eggert
2018-08-22 8:20 ` Andy Moreton
2018-08-22 8:39 ` Andy Moreton
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