Re: Gnat, tasking, Vista

Re: Gnat, tasking, Vista

[tmoran]

Another data point.  A (simple) tasking program compiled with Gnat 3.15p
dies under Windows Vista when it tries to activate a second (ie, other
than the environment) task.  The same executable works fine on W2k and
XP.  The same program compiled with ObjectAda works fine.
  I have several old programs that work(ed).  I'd rather recompile with
their original (3.15p) compiler, with a bugfix to the Gnat runtime,
than recompile them with who knows what new bugs with the current Gnat.
Also, do tasking programs compiled with the current Gnat work on Vista
or are they also broken?

Re: Gnat, tasking, Vista

[Anh Vo]

On Jan 21, 4:51 pm, tmo...@acm.org wrote:
> Another data point.  A (simple) tasking program compiled with Gnat 3.15p
> dies under Windows Vista when it tries to activate a second (ie, other
> than the environment) task.  The same executable works fine on W2k and
> XP.  The same program compiled with ObjectAda works fine.
>   I have several old programs that work(ed).  I'd rather recompile with
> their original (3.15p) compiler, with a bugfix to the Gnat runtime,
> than recompile them with who knows what new bugs with the current Gnat.
> Also, do tasking programs compiled with the current Gnat work on Vista
> or are they also broken?

I just wonder if you were using the latest version of GNAT updated for
Vista?

AV

Re: Gnat, tasking, Vista

[tmoran]

> I just wonder if you were using the latest version of GNAT updated for
> Vista?
   No.  Does its tasking work under Vista?
These are old programs that (except for a new program to test for this
problem) were compiled some time ago with 3.15p  I hate to shake the
dust off the source code of working programs and recompile new versions
hoping that the old bug will be fixed and no new ones will appear -
though I realize I may have to do just that.

Re: Gnat, tasking, Vista

[Pascal Obry]

tmoran@acm.org a �crit :
>    No.  Does its tasking work under Vista?

Yes, GNAT is working fine on Vista.

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|              http://www.obry.net
--| "The best way to travel is by means of imagination"
--|
--| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595

Re: Gnat, tasking, Vista

[Alex R. Mosteo]

Pascal Obry wrote:

> tmoran@acm.org a écrit :
>>    No.  Does its tasking work under Vista?
> 
> Yes, GNAT is working fine on Vista.
> 
> Pascal.

I though there were problems with the stack execution protection? I.e. some
constructions would cause programs to be killed (local subprograms?
trampolines?).

That is, in the pre-last version before being fixed.

Re: Gnat, tasking, Vista

[Pascal Obry]

Alex R. Mosteo a écrit :
> I though there were problems with the stack execution protection? I.e. some
> constructions would cause programs to be killed (local subprograms?
> trampolines?).
> 
> That is, in the pre-last version before being fixed.

Sorry I wasn't clear. There were problems indeed because of the DEP. But 
this has been fixed.

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|              http://www.obry.net
--| "The best way to travel is by means of imagination"
--|
--| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595

Re: Gnat, tasking, Vista

[Jean-Pierre Rosen]

tmoran@acm.org a �crit :
> These are old programs that (except for a new program to test for this
> problem) were compiled some time ago with 3.15p  I hate to shake the
> dust off the source code of working programs and recompile new versions
> hoping that the old bug will be fixed and no new ones will appear -
> though I realize I may have to do just that.
This is a very common (and unfortunate) line of thinking: "I prefer bugs 
that I know rather than (fewer) bugs that I don't know".

Although there is some sense in it, this is just pushing too far. Be 
assured that *lots* of bugs have been fixed since 3.15p, and if new ones 
have been introduced, they are certainly in very complicated and 
unlikely cases, since the latest versions of Gnat are routinely used for 
demanding and critical software - or you can have bugs in the recent 
2005 features, but you are certainly not using them.

Why did I climb on my soapbox? Because I see constantly people asserting 
the risk of making a change, without asserting the risk of *not* making 
the change.

Note that most of the free software community takes the opposite view 
(always use the latest version) and it does not work so bad...
-- 
---------------------------------------------------------
            J-P. Rosen (rosen@adalog.fr)
Visit Adalog's web site at http://www.adalog.fr

Re: Gnat, tasking, Vista

[Phaedrus]

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> This is a very common (and unfortunate) line of thinking: "I prefer bugs 
> that I know rather than (fewer) bugs that I don't know".

Nothing unfortunate about it.  There are multiple paths to success, and 
sometimes the path you know leads you through the mud.  Nasty, yes, but far 
better (From a "staying alive" point of view) than the path you don't know 
which could lead you along a nasty cliff, and possibly over!  Try rephrasing 
this to "When they don't keep me from delivering a product on time, I prefer 
the bugs I know to the bugs that might keep me from delivering and getting 
paid".  Now, see which side of the argument makes more sense.  If the bugs 
that I know keep me from delivering, or add significant cost/time to the 
development project, then I may take the leap.  Or, if I can spare the 
manpower to carefully try the new stuff under controlled conditions, then 
sure.  For example, Vista is the latest and greatest piece of Windows 
software.  Want to bet your development schedule on it's performance?

> Why did I climb on my soapbox? Because I see constantly people asserting 
> the risk of making a change, without asserting the risk of *not* making 
> the change.
>
> Note that most of the free software community takes the opposite view 
> (always use the latest version) and it does not work so bad...

Professional software development is all about managing risk.  For hobbyists 
(and some academics) it's fine to assume the unknown risk that accompanies 
the "latest and greatest" release, but keep in mind that the rest of us have 
to keep our customers satisfied by understanding the cost/benefit ratio of 
these kinds of decisions.

Brian

"Jean-Pierre Rosen" <rosen@adalog.fr> wrote in message 
news:pf64nf.bso.ln@hunter.axlog.fr...
> tmoran@acm.org a �crit :
>> These are old programs that (except for a new program to test for this
>> problem) were compiled some time ago with 3.15p  I hate to shake the
>> dust off the source code of working programs and recompile new versions
>> hoping that the old bug will be fixed and no new ones will appear -
>> though I realize I may have to do just that.
> This is a very common (and unfortunate) line of thinking: "I prefer bugs 
> that I know rather than (fewer) bugs that I don't know".
>
> Although there is some sense in it, this is just pushing too far. Be 
> assured that *lots* of bugs have been fixed since 3.15p, and if new ones 
> have been introduced, they are certainly in very complicated and unlikely 
> cases, since the latest versions of Gnat are routinely used for demanding 
> and critical software - or you can have bugs in the recent 2005 features, 
> but you are certainly not using them.
>
> Why did I climb on my soapbox? Because I see constantly people asserting 
> the risk of making a change, without asserting the risk of *not* making 
> the change.
>
> Note that most of the free software community takes the opposite view 
> (always use the latest version) and it does not work so bad...
> -- 
> ---------------------------------------------------------
>            J-P. Rosen (rosen@adalog.fr)
> Visit Adalog's web site at http://www.adalog.fr 

Re: Gnat, tasking, Vista

[tmoran]

>> This is a very common (and unfortunate) line of thinking: "I prefer bugs
>> that I know rather than (fewer) bugs that I don't know".
>
>Nothing unfortunate about it.  There are multiple paths to success, and
  A bug that is known and successfully worked-around isn't a bug, it's
a feature.  Probably not a nice feature, but not a nasty surprise waiting
to bite you.
  Personally, I usually don't enjoy time spent finding the bugs in
other people's (compilers or OSes etc) code.  I usually have little idea
where the problem might be and there's a lot of grunt work trying to
cut down to a small program that demonstrates the problem (see the
recent thread on "Ada obfuscation").  And when there is a simple
example, learning what to avoid may be its only payback, while those
responsible take months, or even years, to release a corrected version.
  My understanding is that the current Gnat is not a 3.15p with
improvements, but is rather a substantially new thing, with new,
unknown, bugs.  Is that a mis-understanding?

Re: Gnat, tasking, Vista

[Ludovic Brenta]

tmo...@acm.org wrote:
>   My understanding is that the current Gnat is not a 3.15p with
> improvements, but is rather a substantially new thing, with new,
> unknown, bugs.  Is that a mis-understanding?

IMHO your understanding is correct up to a point, but not for the
current version of GCC (4.2.2) or the next version.

When AdaCore merged GNAT into the GCC sources, a long period of
instability ensued for the reasons you outline. I never considered
versions 3.1, 3.2 or 3.3 production-worthy and this is where I agree
with your understanding. However, 3.4 was OK. With version 4.0, a
major change to the back-end ("tree-SSA") introduced some new bugs in
the interface with the Ada front-end, but 4.1 was OK again and the Ada
part of GCC has steadily improved since (i.e. no or very few
regressions). I have a very good feeling about the upcoming GCC 4.3
because AdaCore and Sam Tardieu have recently fixed several dozen old
bugs, most of which have been present since GNAT 3.15p or before. I
anticipate that GCC 4.3 will be the best version of GCC ever as
regards Ada.

Debian reflects this opinion of mine: in 3.1 "Sarge" the Ada compiler
was GNAT 3.15p, in 4.0 "Etch" it is GCC 4.1, and in the upcoming
"Lenny" it will probably be 4.3.

Of course, none of the above applies to GNAT Pro or GNAT GPL Edition
because AdaCore are careful not to introduce regressions when
switching to a new GCC back-end, and do so only infrequently:

GNAT Pro 3.x: GCC 2.8.1
GNAT Pro 5.x and GNAT GPL 2005 Edition: GCC 3.4
GNAT Pro 6.x and GNAT GPL 2006 and 2007 Edition: GCC 4.1

--
Ludovic Brenta.

Re: Gnat, tasking, Vista

[Alex R. Mosteo]

Ludovic Brenta wrote:

> tmo...@acm.org wrote:
>>   My understanding is that the current Gnat is not a 3.15p with
>> improvements, but is rather a substantially new thing, with new,
>> unknown, bugs.  Is that a mis-understanding?
> 
> IMHO your understanding is correct up to a point, but not for the
> current version of GCC (4.2.2) or the next version.
> 
> When AdaCore merged GNAT into the GCC sources, a long period of
> instability ensued for the reasons you outline. I never considered
> versions 3.1, 3.2 or 3.3 production-worthy and this is where I agree
> with your understanding. However, 3.4 was OK. With version 4.0, a
> major change to the back-end ("tree-SSA") introduced some new bugs in
> the interface with the Ada front-end, but 4.1 was OK again and the Ada
> part of GCC has steadily improved since (i.e. no or very few
> regressions). I have a very good feeling about the upcoming GCC 4.3
> because AdaCore and Sam Tardieu have recently fixed several dozen old
> bugs, most of which have been present since GNAT 3.15p or before. I
> anticipate that GCC 4.3 will be the best version of GCC ever as
> regards Ada.

This is very interesting. In regard to Ada 2005 features, the improvement is
also noticeable. GPL 2006 bombed quite frequently, 2007 *much* less to the
point of being a rarity. The only big thing I'm waiting to be useable is
interfaces. I wonder about the amount of differences between the 2007 and
4.x branches.

Re: Gnat, tasking, Vista

[Ludovic Brenta]

Alex R. Mosteo writes:
> Ludovic Brenta wrote:
>
>> tmo...@acm.org wrote:
>>>   My understanding is that the current Gnat is not a 3.15p with
>>> improvements, but is rather a substantially new thing, with new,
>>> unknown, bugs.  Is that a mis-understanding?
>> 
>> IMHO your understanding is correct up to a point, but not for the
>> current version of GCC (4.2.2) or the next version.
>> 
>> When AdaCore merged GNAT into the GCC sources, a long period of
>> instability ensued for the reasons you outline. I never considered
>> versions 3.1, 3.2 or 3.3 production-worthy and this is where I agree
>> with your understanding. However, 3.4 was OK. With version 4.0, a
>> major change to the back-end ("tree-SSA") introduced some new bugs in
>> the interface with the Ada front-end, but 4.1 was OK again and the Ada
>> part of GCC has steadily improved since (i.e. no or very few
>> regressions). I have a very good feeling about the upcoming GCC 4.3
>> because AdaCore and Sam Tardieu have recently fixed several dozen old
>> bugs, most of which have been present since GNAT 3.15p or before. I
>> anticipate that GCC 4.3 will be the best version of GCC ever as
>> regards Ada.
>
> This is very interesting. In regard to Ada 2005 features, the improvement is
> also noticeable. GPL 2006 bombed quite frequently, 2007 *much* less to the
> point of being a rarity. The only big thing I'm waiting to be useable is
> interfaces. I wonder about the amount of differences between the 2007 and
> 4.x branches.

AdaCore normally merge from GNAT Pro into GCC during Stage 1, and then
do almost nothing during Stages 2 and 3 (only a few bug fixes in the
middle-end and the back-end). That, however, changed for GCC 4.3 where
many Ada bug fixes happened during Stage 3 and I think the two
branches are now quite close.  By looking at the timeline of GCC's
development[1], one can establish a rough correspondence between GCC
and GNAT GPL releases:

GCC release | end of stage 1 | GNAT GPL release | release date
--------------------------------------------------------------
4.1         | 2005-04-25     | 2005             | 2005-09-15
4.2         | 2006-01-18     | 2006             | 2006-05-22
4.3         | 2007-01-20     | 2007             | 2007-05-11

The time between the end of Stage 1 and the final release of GCC is
approximately one year:

GCC release | release date | time since end of Stage 1
--------------------------------------------------------
4.1.0        | 2006-02-28  | 10 mo
4.2.0        | 2007-05-13  | 14 mo
4.3.0        | ????-??-??  | 10 mo and counting

This explains why GCC lags behind GNAT Pro and GNAT GPL in terms of
Ada support.

[1] http://gcc.gnu.org/develop.html#timeline

-- 
Ludovic Brenta.

Re: Gnat, tasking, Vista

[Robert A Duff]

tmoran@acm.org writes:

>   A bug that is known and successfully worked-around isn't a bug, it's
> a feature.  Probably not a nice feature, but not a nasty surprise waiting
> to bite you.
>   Personally, I usually don't enjoy time spent finding the bugs in
> other people's (compilers or OSes etc) code.  I usually have little idea
> where the problem might be and there's a lot of grunt work trying to
> cut down to a small program that demonstrates the problem (see the
> recent thread on "Ada obfuscation").  And when there is a simple
> example, learning what to avoid may be its only payback, while those
> responsible take months, or even years, to release a corrected version.
>   My understanding is that the current Gnat is not a 3.15p with
> improvements, but is rather a substantially new thing, with new,
> unknown, bugs.  Is that a mis-understanding?

I can understand the reluctance to upgrade software, in general.
But if you're upgrading the OS (Windows XP to Vista) you really
need to upgrade GNAT as well.  There are several ways in which
Vista is incompatible, so it's not surprising that a version
of GNAT that predates Vista doesn't work!

The DEP issue was mentioned.  I suppose you can turn off DEP
in Vista, either in general, or for particular programs.
(I don't know -- I've never used Vista myself.)

The latest GNAT compiler no longer uses trampolines (which don't
work when DEP is turned on).  However, it can still generate code
that uses trampolines in some cases.  We've mostly fixed that, too,
but there's still a lot of testing to do.  Getting rid of
trampolines is a change in the guts of the back end, and
is target dependent.

Pointers to nested functions in C code will probably continue to use
trampolines for the forseeable future, but we can do better in pure
Ada code.

- Bob

Re: Gnat, tasking, Vista

[Pascal Obry]

Brian,

> Nothing unfortunate about it.  There are multiple paths to success, and 
> sometimes the path you know leads you through the mud.  Nasty, yes, but far 
> better (From a "staying alive" point of view) than the path you don't know 
> which could lead you along a nasty cliff, and possibly over!  Try rephrasing 
> this to "When they don't keep me from delivering a product on time, I prefer 
> the bugs I know to the bugs that might keep me from delivering and getting 
> paid".  Now, see which side of the argument makes more sense. 

This is too far stretched to me! I fully agree with Jean-Piere. We are 
not talking about changing the compiler environment just before a 
release. 3.15p is 5 years old! Compared to recent GNAT versions it is 
full of bugs... Don't tell me that in 5 years there was no room for 
upgrading the compiler.

> Professional software development is all about managing risk.  For hobbyists 

Yes, managing risk... we all do that to some extent. To me your risk 
management is not safe at all. By waiting this long you'll have far more 
trouble to switch. For example some constructs were not properly 
rejected by 3.15p, you'll have to fix that at some point... the longer 
you wait the harder it will be.

Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|              http://www.obry.net
--| "The best way to travel is by means of imagination"
--|
--| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595

Re: Gnat, tasking, Vista

[Ludovic Brenta]

Pascal Obry wrote:
> Brian,
> > Professional software development is all about managing risk.  For hobbyists
>
> Yes, managing risk... we all do that to some extent. To me your risk
> management is not safe at all. By waiting this long you'll have far more
> trouble to switch. For example some constructs were not properly
> rejected by 3.15p, you'll have to fix that at some point... the longer
> you wait the harder it will be.

Not to mention that using an unsupported version of GNAT for mission-
critical professional work is not exactly a good way to "manage
risks"; and neither is "upgrading" to Vista without also upgrading the
compiler.

I understand you may not have the financial resources to pay AdaCore,
but you could at least get free support from the Free Software
community, or even hire contractors to help in case of need, if only
you would use a recent GCC. If you value stability with support, then
Debian stable is for you. Sticking with GNAT 3.15p gives you only one
guarantee: that of getting no support at all.

--
Ludovic Brenta.

Re: Gnat, tasking, Vista

[tmoran]

>3.15p is 5 years old! Compared to recent GNAT versions it is
>full of bugs... Don't tell me that in 5 years there was no room for
>upgrading the compiler.
   I bought Gnat 3.04A on CD in July 1996 and faithfully installed each
release for 7 years, until Gnat 3.15p in August 2003, reporting bugs as
I encountered them.

>..., but 4.1 was OK again and the Ada part of GCC has steadily improved
>since (i.e.  no or very few regressions).  I have a very good feeling
>about the upcoming GCC 4.3
  I'm glad that others have been doing the testing on the GCC Gnat.
Perhaps 4.3 will be as solid as 3.15p, or perhaps 3.15p is incompatible
with Vista and MS will effectively force me to GCC Gnat 4.1
When is 4.3 expected?

Re: Gnat, tasking, Vista

[Ed Falis]

3.15p is incompatible with Vista because of DEP.  The current GNAT GPL is  
compatible with Vista, as is GNAT Pro.  I don't know the status of the FSF  
repository, but I suspect it is also now compatible.

Re: Gnat, tasking, Vista

[Ludovic Brenta]

tmo...@acm.org wrote:
> >..., but 4.1 was OK again and the Ada part of GCC has steadily improved
> >since (i.e.  no or very few regressions).  I have a very good feeling
> >about the upcoming GCC 4.3
>   I'm glad that others have been doing the testing on the GCC Gnat.

That's part of what I meant with "support from the Free Software
community". By joining this community, you can even contribute much-
appreciated testing and bug reports.

> Perhaps 4.3 will be as solid as 3.15p, or perhaps 3.15p is incompatible
> with Vista and MS will effectively force me to GCC Gnat 4.1

I think that, yes, Vista broke compatibility with old executables
compiled with GNAT 3.15p. I know that GNAT GPL 2007 edition was
specifically revised to support Vista. Chances are high that this
support is already in GCC 4.3 but probably not in 4.1. I don't use
Vista (or any proprietary software) myself so I wouldn't know.

> When is 4.3 expected?

GCC 4.3 entered regressions-only mode today [1]. As usual, no date has
yet been announced but I think the release will take place in the next
couple of months. Of course, nothing forces you to wait for a release;
you can use a weekly snapshot at any time and test Vista support for
yourself. The Ada part of GCC will probably not change anymore now.

[1] http://gcc.gnu.org/ml/gcc/2008-01/msg00387.html

--
Ludovic Brenta.

Re: Gnat, tasking, Vista

[Jean-Pierre Rosen]

Phaedrus a �crit :
> Professional software development is all about managing risk.  For hobbyists 
> (and some academics) it's fine to assume the unknown risk that accompanies 
> the "latest and greatest" release, but keep in mind that the rest of us have 
> to keep our customers satisfied by understanding the cost/benefit ratio of 
> these kinds of decisions.
> 
I agree absolutely with that statement. My rant is because, in many 
cases that I've seen, people overestimate the risk of changing and 
underestimate the risk of not changing. Very often, they assume (without 
any evidence) that there is no risk in not changing.

And as Pascal noted, if you don't follow evolution, the cost of changing 
becomes bigger and bigger, and eventually you reach a state where 
changing becomes impossible - and then you are stuck with obsolete 
technology. This is part of the risk of not changing, although few 
people take this into consideration.

-- 
---------------------------------------------------------
            J-P. Rosen (rosen@adalog.fr)
Visit Adalog's web site at http://www.adalog.fr