From: "Vladimir Olensky" <vladimir_olensky@yahoo.com>
Subject: Re: Ammo-zilla
Date: 1999/11/03
Date: 1999-11-03T00:00:00+00:00 [thread overview]
Message-ID: <s20tckqd24291@corp.supernews.com> (raw)
In-Reply-To: 7vncgr$bpg$1@nnrp1.deja.com
Robert Dewar wrote in message <7vncgr$bpg$1@nnrp1.deja.com>...
>In article <wcck8o0yh5x.fsf@world.std.com>,
> Robert A Duff <bobduff@world.std.com> wrote:
>> Bugs in the GC itself have exactly the same sort
>> of nasty consequences we're talking about.
>
>Absolutely! And that's what's scary! These bugs in the GC itself
>are among the most horrible bugs I have ever tackled (the one
>exception being subtle hardware design errors). The idea that
>an Ada user with little awareness of what is going on at a low
>level can create bugs of comparable scariness by casual
>incorrect use of unchecked conversion seems unacceptably
>risky to me.
As for me I fully support that.
I think that any unchecked conversions should
be disallowed for pointers that are traced by GC.
It is not only extremely unsafe but I do not see any sense
in that if language is extended to support GC.
Any manipulations with such pointers should be allowed only
within GC manager package. GC client should not have any access
to such operations at all. GC mechanism should be completely
hidden from the client. Depending on particular GC
mechanism any pointer traced by GC may be not only a pure
"ROOT" (in traditional GC terminology) which references object
storage location but it may also be a reference to the entry
record in GC Address Descriptor Table which in turn in one
of it's fields contains the real "ROOT" of the pointers tree/net
as well as other necessary fields (referenced object tag, size etc.).
Last approach was described in my other posts.
For such GC_Pointer unchecked conversions done by
the client makes no sense at all.
This restriction could be done using language support for GC.
Let's suppose that we have additional keyword TRACED
that applied to the ACCESS TYPES controlled by GC.
(This TRACED ACCESS TYPE could be bound
to particular GC using standard Ada construct:
for T'Storage_Pool use Ada.GC.GC_Name_Storage_Pool).
When access type is declared to be traced compiler should
not allow any unchecked conversions with that type in standard
mode.
In may allowed only using additional pragmas.
Regards,
Vladimir Olensky
next prev parent reply other threads:[~1999-11-03 0:00 UTC|newest]
Thread overview: 92+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-10-23 0:00 Ammo-zilla Stanley R. Allen
1999-10-24 0:00 ` Ammo-zilla Aidan Skinner
1999-10-24 0:00 ` Ammo-zilla Robert Dewar
1999-10-24 0:00 ` Ammo-zilla David Botton
1999-10-28 0:00 ` Ammo-zilla Charles Hixson
1999-10-28 0:00 ` Ammo-zilla Matthew Heaney
1999-10-28 0:00 ` Ammo-zilla mitch
1999-10-29 0:00 ` Ammo-zilla Matthew Heaney
1999-10-28 0:00 ` Ammo-zilla Laurent Guerby
1999-10-28 0:00 ` Ammo-zilla Charles Hixson
1999-10-29 0:00 ` Ada and GC (Was Re: Ammo-zilla) Vladimir Olensky
1999-10-29 0:00 ` David Botton
1999-10-31 0:00 ` Vladimir Olensky
1999-10-30 0:00 ` Samuel T. Harris
1999-10-30 0:00 ` David Botton
1999-10-28 0:00 ` Ammo-zilla David Starner
1999-10-29 0:00 ` Ammo-zilla Larry Kilgallen
1999-10-29 0:00 ` Ammo-zilla David Starner
1999-10-29 0:00 ` Ammo-zilla Matthew Heaney
1999-10-29 0:00 ` Ammo-zilla Charles Hixson
1999-10-29 0:00 ` Ammo-zilla David Botton
1999-10-29 0:00 ` Ammo-zilla mike
1999-10-29 0:00 ` Ammo-zilla David Botton
1999-10-31 0:00 ` Ammo-zilla Robert Dewar
1999-11-02 0:00 ` Ammo-zilla Charles Hixson
1999-11-03 0:00 ` Ammo-zilla Wes Groleau
1999-11-01 0:00 ` Ammo-zilla Geoff Bull
1999-10-29 0:00 ` Ammo-zilla Tucker Taft
1999-10-30 0:00 ` Ammo-zilla Lutz Donnerhacke
1999-10-31 0:00 ` Ammo-zilla Robert Dewar
1999-10-31 0:00 ` Garbage colletion Lutz Donnerhacke
1999-11-01 0:00 ` Robert Dewar
1999-11-01 0:00 ` Lutz Donnerhacke
1999-11-01 0:00 ` Larry Kilgallen
1999-11-01 0:00 ` Robert Dewar
1999-11-01 0:00 ` Gnat IDE (was: Garbage colletion) Ted Dennison
1999-11-01 0:00 ` Garbage colletion Lutz Donnerhacke
1999-11-01 0:00 ` Robert Dewar
1999-11-04 0:00 ` Didier Utheza
1999-11-04 0:00 ` David Starner
1999-10-31 0:00 ` Ammo-zilla Robert Dewar
1999-10-31 0:00 ` Ammo-zilla David Starner
1999-11-01 0:00 ` Ammo-zilla Robert Dewar
1999-11-01 0:00 ` Ada and GC. Was: Ammo-zilla Vladimir Olensky
1999-11-01 0:00 ` Tucker Taft
1999-11-02 0:00 ` Vladimir Olensky
1999-11-02 0:00 ` Robert Dewar
1999-11-02 0:00 ` Charles Hixson
1999-11-03 0:00 ` Robert Dewar
1999-11-03 0:00 ` Charles Hixson
1999-11-01 0:00 ` Vladimir Olensky
1999-11-01 0:00 ` Ammo-zilla Robert Dewar
1999-11-01 0:00 ` Ammo-zilla Robert A Duff
1999-11-01 0:00 ` Ammo-zilla Robert Dewar
1999-11-02 0:00 ` Ammo-zilla Robert A Duff
1999-11-02 0:00 ` Ammo-zilla Robert Dewar
1999-11-03 0:00 ` Vladimir Olensky [this message]
1999-11-03 0:00 ` Ammo-zilla Robert Dewar
1999-11-04 0:00 ` Ada GC (was Re: Ammo-zilla) Vladimir Olensky
1999-11-06 0:00 ` Robert Dewar
1999-11-06 0:00 ` Vladimir Olensky
1999-11-06 0:00 ` Robert Dewar
1999-11-06 0:00 ` Vladimir Olensky
1999-11-09 0:00 ` Robert A Duff
1999-11-10 0:00 ` Vladimir Olensky
1999-11-10 0:00 ` Richard D Riehle
1999-11-10 0:00 ` Nick Roberts
1999-11-12 0:00 ` Robert I. Eachus
1999-11-12 0:00 ` Didier Utheza
1999-11-12 0:00 ` Robert Dewar
1999-11-10 0:00 ` Robert A Duff
1999-11-12 0:00 ` Robert I. Eachus
1999-11-04 0:00 ` Ada GC (was Ammo-zilla) Nick Roberts
1999-11-04 0:00 ` Wes Groleau
1999-11-01 0:00 ` Ammo-zilla Vladimir Olensky
1999-10-30 0:00 ` Ammo-zilla Lutz Donnerhacke
1999-10-30 0:00 ` Ammo-zilla Matthew Heaney
1999-10-31 0:00 ` Ammo-zilla Robert Dewar
1999-10-29 0:00 ` Ammo-zilla Robert I. Eachus
1999-10-28 0:00 ` Ammo-zilla Tucker Taft
1999-10-31 0:00 ` Ammo-zilla Brian Rogoff
1999-11-01 0:00 ` Ammo-zilla Robert Dewar
1999-11-01 0:00 ` Ammo-zilla Brian Rogoff
1999-11-02 0:00 ` Ammo-zilla Robert Dewar
1999-11-02 0:00 ` Ammo-zilla Brian Rogoff
1999-11-02 0:00 ` Ammo-zilla Robert A Duff
1999-10-31 0:00 ` Ammo-zilla Robert Dewar
1999-10-24 0:00 ` Ammo-zilla Aidan Skinner
1999-10-25 0:00 ` Ammo-zilla Jean-Pierre Rosen
1999-10-24 0:00 ` Ammo-zilla Matthew Heaney
1999-10-24 0:00 ` Ammo-zilla Robert Dewar
1999-10-24 0:00 ` Ammo-zilla David Botton
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