From: Marc Glisse <marc.glisse@inria.fr>
To: gcc@gcc.gnu.org
Subject: Re: adding destroyable objects into Ggc
Date: Thu, 20 Oct 2011 08:37:00 -0000 [thread overview]
Message-ID: <alpine.DEB.2.02.1110200903470.2398@laptop-mg.saclay.inria.fr> (raw)
In-Reply-To: <20111020080753.a895eae452bb25e312ebf617@starynkevitch.net>
On Thu, 20 Oct 2011, Basile Starynkevitch wrote:
> On Wed, 19 Oct 2011 21:17:47 -0700
> Lawrence Crowl <crowl@google.com> wrote:
>
>> Basile Starynkevitch <basile@starynkevitch.net>
>>> I would like to add destroyable objects into Ggc (the GCC garbage
>>> collector, see files gcc/ggc*.[ch]).
>>>
>>> The main motivation is to permit C++ objects to be garbage collected
>>> (I discussed that briefly in the Gcc meeting at Google in London):
>>> adding destroyable object is a prerequisite for that goal.
>>
>> The C++ standard has support for garbage collection, and the general
>> consensus of the committee is that object garbage collected do not
>> execute their destructors.
>
> I don't understand well this decision.
If you just let the objects leak, their destructor is not executed.
Garbage collection reuses that memory in such a way that you can't notice
the difference with a leak (except that you don't get OOM).
> PPL [Parma Polyhedra Library] data, like e.g. ppl_Constraint_t [from
> header <ppl_c.h> that is, using a C API] comes to mind. If you want to
> share PPL stuff between several passes, it can be very handy to add PPL
> data inside GTY-ed stuff. If that GTY-ed stuff is deleted by Ggc, and if
> the PPL destructor (e.g. ppl_delete_Constraint in that case) is not
> called, you get a memory leak.
Or you could imagine the garbage collector also reclaiming that memory.
> Other usages include other finalized data, like FILE* [if a plugin need
> a FILE* inside GTY-ed data to be shared by several passes, it would be
> handy that when the GTY-ed object is deleted, the FILE* is fclosed] or
> even std::ostringstream or std::ostring-s shared between several passes.
Yes, those are the usual arguments for a finalizer.
--
Marc Glisse
next prev parent reply other threads:[~2011-10-20 7:11 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-18 16:35 Basile Starynkevitch
2011-10-18 16:43 ` Duncan Sands
2011-10-18 16:53 ` Basile Starynkevitch
2011-10-18 17:11 ` Ian Lance Taylor
2011-10-18 17:14 ` Gabriel Dos Reis
2011-10-18 17:20 ` Basile Starynkevitch
2011-10-18 17:36 ` Ian Lance Taylor
2011-10-18 17:41 ` Basile Starynkevitch
2011-10-18 17:50 ` Ian Lance Taylor
2011-10-18 17:53 ` Basile Starynkevitch
2011-10-18 18:03 ` Jonathan Wakely
2011-10-18 18:11 ` Ian Lance Taylor
2011-10-18 19:41 ` Basile Starynkevitch
2011-10-18 20:52 ` Gabriel Dos Reis
2011-10-18 19:50 ` Gabriel Dos Reis
2011-10-18 23:11 ` Basile Starynkevitch
2011-10-19 0:49 ` Jonathan Wakely
2011-10-18 19:46 ` Gabriel Dos Reis
2011-10-19 6:04 ` Chiheng Xu
2011-10-19 6:08 ` Basile Starynkevitch
2011-10-19 6:43 ` Chiheng Xu
2011-10-19 6:12 ` Gabriel Dos Reis
2011-10-19 6:17 ` Basile Starynkevitch
2011-10-19 6:22 ` Chiheng Xu
[not found] ` <20111019080021.4e1acb3687fc8ceacc2fd7a3@starynkevitch.net>
[not found] ` <CAAiZkiB-aXfE8MyY_S6YvecdxgsBnuBHp3JDWx4kirVkQx8w+A@mail.gmail.com>
2011-10-19 7:41 ` Gabriel Dos Reis
2011-10-19 7:43 ` Basile Starynkevitch
2011-10-19 12:14 ` Gabriel Dos Reis
2011-10-19 13:31 ` Duncan Sands
2011-10-19 22:19 ` Jonathan Wakely
2011-10-19 15:06 ` David Malcolm
2011-10-20 6:03 ` Lawrence Crowl
2011-10-20 8:29 ` Basile Starynkevitch
2011-10-20 8:37 ` Marc Glisse [this message]
2011-10-20 8:38 ` Basile Starynkevitch
2011-10-20 11:57 ` Marc Glisse
2011-10-20 12:10 ` Basile Starynkevitch
2011-10-20 15:34 ` Marc Glisse
2011-10-21 9:03 ` Basile Starynkevitch
2011-10-21 12:24 ` Marc Glisse
2011-10-21 12:28 ` Richard Guenther
2011-10-21 23:53 ` Basile Starynkevitch
2011-10-22 1:31 ` Gabriel Dos Reis
2011-10-22 11:20 ` Basile Starynkevitch
2011-10-23 13:50 ` Richard Guenther
2011-10-19 15:56 ` Laurynas Biveinis
2011-10-19 16:54 ` Basile Starynkevitch
2011-10-20 8:52 ` Laurynas Biveinis
2011-10-20 12:27 ` Basile Starynkevitch
2011-10-20 12:51 ` Andrew Haley
2011-10-20 14:07 ` Basile Starynkevitch
2011-10-20 13:10 ` Duncan Sands
2011-10-20 14:52 ` Torvald Riegel
2011-10-20 15:14 ` Jonathan Wakely
2011-10-20 15:26 ` Richard Guenther
2011-10-20 17:23 ` Basile Starynkevitch
2011-10-20 18:38 ` Jonathan Wakely
2011-10-18 18:39 ` Jonathan Wakely
2011-10-18 18:48 ` Basile Starynkevitch
2011-10-18 19:42 ` Jonathan Wakely
2011-10-18 19:45 ` Basile Starynkevitch
2011-10-18 22:43 ` Gabriel Dos Reis
2011-10-18 21:24 ` Gabriel Dos Reis
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