From: Jim Blandy <jimb@red-bean.com>
To: Tom Tromey <tromey@redhat.com>
Cc: Paul Koning <paulkoning@comcast.net>, gdb-patches@sourceware.org
Subject: Re: Python: fetch value when building gdb.Value object
Date: Fri, 14 Oct 2011 23:36:00 -0000 [thread overview]
Message-ID: <CAHgb+0nKOxaBR2=2NLdq5hN0d4tkgDawZy+ztrA5MB_sONjGQA@mail.gmail.com> (raw)
In-Reply-To: <m3y5x0pxqg.fsf@fleche.redhat.com>
On Tue, Oct 4, 2011 at 8:44 AM, Tom Tromey <tromey@redhat.com> wrote:
> The reason is that eager fetching can be very expensive. E.g., you may
> construct an intermediate value that is a very large array, but intend
> only to reference a few elements. This can be done efficiently by gdb,
> but eager fetching will defeat that.
Yeah, this worried me, too. In C, array values are automatically
converted to pointers to their first element, but GDB doesn't (last I
checked) do this; instead, it relies on the lazy value fetching to get
the same effect. Unfortunately, this means that unlazying values can
have drastic effects on memory consumption that one would not expect
if one knows the C semantics.
prev parent reply other threads:[~2011-10-14 23:36 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-21 16:17 Paul Koning
2011-09-28 19:29 ` Phil Muldoon
2011-09-28 20:06 ` Paul Koning
2011-10-04 15:43 ` Tom Tromey
2011-09-28 20:42 ` Paul Koning
2011-10-01 9:05 ` Jan Kratochvil
2011-10-03 10:22 ` Phil Muldoon
2011-10-04 15:40 ` Tom Tromey
2011-10-01 9:29 ` Jan Kratochvil
2011-10-01 10:23 ` Pedro Alves
2011-10-01 11:03 ` Jan Kratochvil
2011-10-01 12:17 ` Python: fetch value when building gdb.Value object [rediff] Jan Kratochvil
2011-10-01 18:58 ` Paul Koning
2011-10-03 10:19 ` Phil Muldoon
2011-10-03 16:16 ` Paul Koning
2011-10-01 1:00 ` [PING] [RFA] Re: Python: fetch value when building gdb.Value object Paul Koning
2011-10-04 15:45 ` Tom Tromey
2011-10-04 15:51 ` Paul Koning
2011-10-14 20:03 ` Tom Tromey
2011-10-14 20:30 ` Paul Koning
2011-10-19 20:56 ` Tom Tromey
2011-10-19 20:58 ` Paul Koning
2011-10-20 15:09 ` Tom Tromey
2011-10-21 7:46 ` Paul Koning
2011-10-21 17:13 ` Tom Tromey
2011-10-14 23:36 ` Jim Blandy [this message]
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