* vacation and strict aliasing
@ 1999-09-09 17:56 Joe Buck
1999-09-11 0:16 ` Richard Stallman
1999-09-30 18:02 ` Joe Buck
0 siblings, 2 replies; 12+ messages in thread
From: Joe Buck @ 1999-09-09 17:56 UTC (permalink / raw)
To: gcc
I'm about to leave town for a couple of weeks, so I won't be able
to keep up my end of the type-aliasing battle. But I hope that the
matter isn't just dropped.
As John Vickers points out, there's a lot of free software out there
that is effectively not being maintained, and users or fixers of the
software will require assistance.
I'm kinda hoping that at least someone will be motivated to experiment
with a patch to try to produce some warnings. Yes, I know it's not
a good thing to ask someone else to do the work, so if no one manages
to get around to this in the next couple of weeks, I'll try some hacking
myself when I get back in town.
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-09 17:56 vacation and strict aliasing Joe Buck
@ 1999-09-11 0:16 ` Richard Stallman
1999-09-12 17:59 ` Marc Lehmann
1999-09-30 18:02 ` Richard Stallman
1999-09-30 18:02 ` Joe Buck
1 sibling, 2 replies; 12+ messages in thread
From: Richard Stallman @ 1999-09-11 0:16 UTC (permalink / raw)
To: jbuck; +Cc: gcc
I'm about to leave town for a couple of weeks, so I won't be able
to keep up my end of the type-aliasing battle. But I hope that the
matter isn't just dropped.
As John Vickers points out, there's a lot of free software out there
that is effectively not being maintained, and users or fixers of the
software will require assistance.
While a warning would help the situation, making some these programs
once again produce working code would be a very effective kind
of help. We are not certain we can keep those programs forever,
but even if it is just for a few years, that would be good.
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-11 0:16 ` Richard Stallman
@ 1999-09-12 17:59 ` Marc Lehmann
1999-09-13 3:29 ` Russ Allbery
` (2 more replies)
1999-09-30 18:02 ` Richard Stallman
1 sibling, 3 replies; 12+ messages in thread
From: Marc Lehmann @ 1999-09-12 17:59 UTC (permalink / raw)
To: gcc
On Sat, Sep 11, 1999 at 03:25:53AM -0400, Richard Stallman <rms@gnu.org> wrote:
> As John Vickers points out, there's a lot of free software out there
> that is effectively not being maintained, and users or fixers of the
> software will require assistance.
>
> While a warning would help the situation, making some these programs
> once again produce working code would be a very effective kind
> of help. We are not certain we can keep those programs forever,
> but even if it is just for a few years, that would be good.
Has anobdy made a list of programs that brak because of the aliasing issue? I
only know these:
- linux-kernel (known and worked around)
- perl (worked around, but its not clear wether theres a bug)
I imagine that programs might break because of other reasons as well, e.g.
libc enhancements, other optimizations in gcc, races...
--
-----==- |
----==-- _ |
---==---(_)__ __ ____ __ Marc Lehmann +--
--==---/ / _ \/ // /\ \/ / pcg@goof.com |e|
-=====/_/_//_/\_,_/ /_/\_\ XX11-RIPE --+
The choice of a GNU generation |
|
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-12 17:59 ` Marc Lehmann
@ 1999-09-13 3:29 ` Russ Allbery
1999-09-13 13:00 ` Marc Lehmann
1999-09-30 18:02 ` Russ Allbery
1999-09-14 3:51 ` Marc Espie
1999-09-30 18:02 ` Marc Lehmann
2 siblings, 2 replies; 12+ messages in thread
From: Russ Allbery @ 1999-09-13 3:29 UTC (permalink / raw)
To: gcc
Marc Lehmann <marc@gimp.org> writes:
> Has anobdy made a list of programs that brak because of the aliasing
> issue? I only know these:
> - linux-kernel (known and worked around)
> - perl (worked around, but its not clear wether theres a bug)
Not at all clear. I don't get any test suite failures with a version of
Perl prior to any workarounds and compiled with gcc 2.95. If it caused
any bugs, they're pretty subtle.
--
Russ Allbery (rra@stanford.edu) <URL: http://www.eyrie.org/~eagle/ >
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-13 3:29 ` Russ Allbery
@ 1999-09-13 13:00 ` Marc Lehmann
1999-09-30 18:02 ` Marc Lehmann
1999-09-30 18:02 ` Russ Allbery
1 sibling, 1 reply; 12+ messages in thread
From: Marc Lehmann @ 1999-09-13 13:00 UTC (permalink / raw)
To: gcc
On Mon, Sep 13, 1999 at 03:28:54AM -0700, Russ Allbery <rra@stanford.edu> wrote:
> > Has anobdy made a list of programs that brak because of the aliasing
> > issue? I only know these:
>
> > - linux-kernel (known and worked around)
> > - perl (worked around, but its not clear wether theres a bug)
>
> Not at all clear. I don't get any test suite failures with a version of
> Perl prior to any workarounds and compiled with gcc 2.95. If it caused
> any bugs, they're pretty subtle.
I really wasn't clear ;) There is a workaround for a known issue that is
"invalid" code (XPVHV * vs. different * in different structs), but gcc
does not cause any harm.
That code is problematic anyway, as an XPVHV * need not have the same
layout as other pointers.
--
-----==- |
----==-- _ |
---==---(_)__ __ ____ __ Marc Lehmann +--
--==---/ / _ \/ // /\ \/ / pcg@goof.com |e|
-=====/_/_//_/\_,_/ /_/\_\ XX11-RIPE --+
The choice of a GNU generation |
|
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-12 17:59 ` Marc Lehmann
1999-09-13 3:29 ` Russ Allbery
@ 1999-09-14 3:51 ` Marc Espie
1999-09-30 18:02 ` Marc Espie
1999-09-30 18:02 ` Marc Lehmann
2 siblings, 1 reply; 12+ messages in thread
From: Marc Espie @ 1999-09-14 3:51 UTC (permalink / raw)
To: marc; +Cc: egcs
In article < 19990913003520.B14917@cerebro.laendle > you write:
>Has anobdy made a list of programs that brak because of the aliasing issue? I
>only know these:
>- linux-kernel (known and worked around)
>- perl (worked around, but its not clear wether theres a bug)
Niklas Hallqvist traced a bug in the OpenBSD kernel to aliasing issues.
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-11 0:16 ` Richard Stallman
1999-09-12 17:59 ` Marc Lehmann
@ 1999-09-30 18:02 ` Richard Stallman
1 sibling, 0 replies; 12+ messages in thread
From: Richard Stallman @ 1999-09-30 18:02 UTC (permalink / raw)
To: jbuck; +Cc: gcc
I'm about to leave town for a couple of weeks, so I won't be able
to keep up my end of the type-aliasing battle. But I hope that the
matter isn't just dropped.
As John Vickers points out, there's a lot of free software out there
that is effectively not being maintained, and users or fixers of the
software will require assistance.
While a warning would help the situation, making some these programs
once again produce working code would be a very effective kind
of help. We are not certain we can keep those programs forever,
but even if it is just for a few years, that would be good.
^ permalink raw reply [flat|nested] 12+ messages in thread
* vacation and strict aliasing
1999-09-09 17:56 vacation and strict aliasing Joe Buck
1999-09-11 0:16 ` Richard Stallman
@ 1999-09-30 18:02 ` Joe Buck
1 sibling, 0 replies; 12+ messages in thread
From: Joe Buck @ 1999-09-30 18:02 UTC (permalink / raw)
To: gcc
I'm about to leave town for a couple of weeks, so I won't be able
to keep up my end of the type-aliasing battle. But I hope that the
matter isn't just dropped.
As John Vickers points out, there's a lot of free software out there
that is effectively not being maintained, and users or fixers of the
software will require assistance.
I'm kinda hoping that at least someone will be motivated to experiment
with a patch to try to produce some warnings. Yes, I know it's not
a good thing to ask someone else to do the work, so if no one manages
to get around to this in the next couple of weeks, I'll try some hacking
myself when I get back in town.
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-13 13:00 ` Marc Lehmann
@ 1999-09-30 18:02 ` Marc Lehmann
0 siblings, 0 replies; 12+ messages in thread
From: Marc Lehmann @ 1999-09-30 18:02 UTC (permalink / raw)
To: gcc
On Mon, Sep 13, 1999 at 03:28:54AM -0700, Russ Allbery <rra@stanford.edu> wrote:
> > Has anobdy made a list of programs that brak because of the aliasing
> > issue? I only know these:
>
> > - linux-kernel (known and worked around)
> > - perl (worked around, but its not clear wether theres a bug)
>
> Not at all clear. I don't get any test suite failures with a version of
> Perl prior to any workarounds and compiled with gcc 2.95. If it caused
> any bugs, they're pretty subtle.
I really wasn't clear ;) There is a workaround for a known issue that is
"invalid" code (XPVHV * vs. different * in different structs), but gcc
does not cause any harm.
That code is problematic anyway, as an XPVHV * need not have the same
layout as other pointers.
--
-----==- |
----==-- _ |
---==---(_)__ __ ____ __ Marc Lehmann +--
--==---/ / _ \/ // /\ \/ / pcg@goof.com |e|
-=====/_/_//_/\_,_/ /_/\_\ XX11-RIPE --+
The choice of a GNU generation |
|
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-12 17:59 ` Marc Lehmann
1999-09-13 3:29 ` Russ Allbery
1999-09-14 3:51 ` Marc Espie
@ 1999-09-30 18:02 ` Marc Lehmann
2 siblings, 0 replies; 12+ messages in thread
From: Marc Lehmann @ 1999-09-30 18:02 UTC (permalink / raw)
To: gcc
On Sat, Sep 11, 1999 at 03:25:53AM -0400, Richard Stallman <rms@gnu.org> wrote:
> As John Vickers points out, there's a lot of free software out there
> that is effectively not being maintained, and users or fixers of the
> software will require assistance.
>
> While a warning would help the situation, making some these programs
> once again produce working code would be a very effective kind
> of help. We are not certain we can keep those programs forever,
> but even if it is just for a few years, that would be good.
Has anobdy made a list of programs that brak because of the aliasing issue? I
only know these:
- linux-kernel (known and worked around)
- perl (worked around, but its not clear wether theres a bug)
I imagine that programs might break because of other reasons as well, e.g.
libc enhancements, other optimizations in gcc, races...
--
-----==- |
----==-- _ |
---==---(_)__ __ ____ __ Marc Lehmann +--
--==---/ / _ \/ // /\ \/ / pcg@goof.com |e|
-=====/_/_//_/\_,_/ /_/\_\ XX11-RIPE --+
The choice of a GNU generation |
|
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-13 3:29 ` Russ Allbery
1999-09-13 13:00 ` Marc Lehmann
@ 1999-09-30 18:02 ` Russ Allbery
1 sibling, 0 replies; 12+ messages in thread
From: Russ Allbery @ 1999-09-30 18:02 UTC (permalink / raw)
To: gcc
Marc Lehmann <marc@gimp.org> writes:
> Has anobdy made a list of programs that brak because of the aliasing
> issue? I only know these:
> - linux-kernel (known and worked around)
> - perl (worked around, but its not clear wether theres a bug)
Not at all clear. I don't get any test suite failures with a version of
Perl prior to any workarounds and compiled with gcc 2.95. If it caused
any bugs, they're pretty subtle.
--
Russ Allbery (rra@stanford.edu) <URL: http://www.eyrie.org/~eagle/ >
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: vacation and strict aliasing
1999-09-14 3:51 ` Marc Espie
@ 1999-09-30 18:02 ` Marc Espie
0 siblings, 0 replies; 12+ messages in thread
From: Marc Espie @ 1999-09-30 18:02 UTC (permalink / raw)
To: marc; +Cc: egcs
In article < 19990913003520.B14917@cerebro.laendle > you write:
>Has anobdy made a list of programs that brak because of the aliasing issue? I
>only know these:
>- linux-kernel (known and worked around)
>- perl (worked around, but its not clear wether theres a bug)
Niklas Hallqvist traced a bug in the OpenBSD kernel to aliasing issues.
^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~1999-09-30 18:02 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
1999-09-09 17:56 vacation and strict aliasing Joe Buck
1999-09-11 0:16 ` Richard Stallman
1999-09-12 17:59 ` Marc Lehmann
1999-09-13 3:29 ` Russ Allbery
1999-09-13 13:00 ` Marc Lehmann
1999-09-30 18:02 ` Marc Lehmann
1999-09-30 18:02 ` Russ Allbery
1999-09-14 3:51 ` Marc Espie
1999-09-30 18:02 ` Marc Espie
1999-09-30 18:02 ` Marc Lehmann
1999-09-30 18:02 ` Richard Stallman
1999-09-30 18:02 ` Joe Buck
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