RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Saturday, July 06, 2002 10:47 PM
> To: Gabriel Dos Reis; gcc@gcc.gnu.org
> Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> > Thanks for the clarifications.  So all that needs is to make an
> > exception to our earlier commitment that minor releases won't
> > introduce ABI incompatibility; or make an exception to our scheduled
> > development plan.  I don't have any strong opinion.  But if we were
> 
> Well, we could could make a sub-branch from the 3.1 branch for the
> amended ABI, and call it 3.1bis .

Speaking for myself, as a GCC user mainly for this, I feel it a lot clearer
to stick to the "minor releases only fix bugs but are otherwise fully
compatible" scheme; thus it seems to me that to avoid end user brain damage,
if a release with an ABI that we may reasonably expect to be compatible with
upcoming releases (but need to be incompatible with the currently almost
released 3.1.1) then it should be named 3.2.

Then what was for now named 3.2 byt GCC *developpers* (a much smaller
community than gcc *users*) may have to be renamed 3.3 if there is
incompatibilities with this 3.2 release (or major change in features), but
may just become 3.2.1 otherwise. 

In all cases the numbering scheme will then remain coherent and easily
understandable by users.

Just my .02$

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Gabriel Dos Reis]

Bernard Dautrevaux <Dautrevaux@microprocess.com> writes:

| Then what was for now named 3.2 byt GCC *developpers* (a much smaller
| community than gcc *users*) may have to be renamed 3.3 if there is
| incompatibilities with this 3.2 release (or major change in features), but
| may just become 3.2.1 otherwise. 

If people are complaining for incessant ABI incompatibilities between
GCC releases, then it occurs to me that the ABI changes in your proposed
3.3 version should also be incorporated into your proposed 3.2 version.
Which means, we delay the release for the actual 3.2 to incorporate
all needed and known ABI changes.

Right now, does anyone produce testcases that show that the ABI
changes under discussion affect in unreconciliable ways current
softwares? 

-- Gaby

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Joern Rennecke]

Bernard Dautrevaux wrote:
> 
> > -----Original Message-----
> > From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> > Sent: Saturday, July 06, 2002 10:47 PM
> > To: Gabriel Dos Reis; gcc@gcc.gnu.org
> > Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> > obrien@freebsd.org
> > Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> >
> >
> > > Thanks for the clarifications.  So all that needs is to make an
> > > exception to our earlier commitment that minor releases won't
> > > introduce ABI incompatibility; or make an exception to our scheduled
> > > development plan.  I don't have any strong opinion.  But if we were
> >
> Then what was for now named 3.2 byt GCC *developpers* (a much smaller
> community than gcc *users*) may have to be renamed 3.3 if there is
> incompatibilities with this 3.2 release (or major change in features), but
> may just become 3.2.1 otherwise.

But then you'd have a massive amount of new. possibly destabilizing code
in 3.2.1 versus 3.2.  Users generally expect a x.y.1 release to me more
stable than the preceding x.y.0 release.

And, on the other hand, 3.2 would be rather a disappointment regarding
new features and ports.
	
-- 
--------------------------
SuperH
2430 Aztec West / Almondsbury / BRISTOL / BS32 4AQ
T:+44 1454 462330

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Saturday, July 06, 2002 10:47 PM
> To: Gabriel Dos Reis; gcc@gcc.gnu.org
> Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> > Thanks for the clarifications.  So all that needs is to make an
> > exception to our earlier commitment that minor releases won't
> > introduce ABI incompatibility; or make an exception to our scheduled
> > development plan.  I don't have any strong opinion.  But if we were
> 
> Well, we could could make a sub-branch from the 3.1 branch for the
> amended ABI, and call it 3.1bis .

Speaking for myself, as a GCC user mainly for this, I feel it a lot clearer
to stick to the "minor releases only fix bugs but are otherwise fully
compatible" scheme; thus it seems to me that to avoid end user brain damage,
if a release with an ABI that we may reasonably expect to be compatible with
upcoming releases (but need to be incompatible with the currently almost
released 3.1.1) then it should be named 3.2.

Then what was for now named 3.2 byt GCC *developpers* (a much smaller
community than gcc *users*) may have to be renamed 3.3 if there is
incompatibilities with this 3.2 release (or major change in features), but
may just become 3.2.1 otherwise. 

In all cases the numbering scheme will then remain coherent and easily
understandable by users.

Just my .02$

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Saturday, July 06, 2002 10:47 PM
> To: Gabriel Dos Reis; gcc@gcc.gnu.org
> Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> > Thanks for the clarifications.  So all that needs is to make an
> > exception to our earlier commitment that minor releases won't
> > introduce ABI incompatibility; or make an exception to our scheduled
> > development plan.  I don't have any strong opinion.  But if we were
> 
> Well, we could could make a sub-branch from the 3.1 branch for the
> amended ABI, and call it 3.1bis .

Speaking for myself, as a GCC user mainly for this, I feel it a lot clearer
to stick to the "minor releases only fix bugs but are otherwise fully
compatible" scheme; thus it seems to me that to avoid end user brain damage,
if a release with an ABI that we may reasonably expect to be compatible with
upcoming releases (but need to be incompatible with the currently almost
released 3.1.1) then it should be named 3.2.

Then what was for now named 3.2 byt GCC *developpers* (a much smaller
community than gcc *users*) may have to be renamed 3.3 if there is
incompatibilities with this 3.2 release (or major change in features), but
may just become 3.2.1 otherwise. 

In all cases the numbering scheme will then remain coherent and easily
understandable by users.

Just my .02$

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Saturday, July 06, 2002 10:47 PM
> To: Gabriel Dos Reis; gcc@gcc.gnu.org
> Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> > Thanks for the clarifications.  So all that needs is to make an
> > exception to our earlier commitment that minor releases won't
> > introduce ABI incompatibility; or make an exception to our scheduled
> > development plan.  I don't have any strong opinion.  But if we were
> 
> Well, we could could make a sub-branch from the 3.1 branch for the
> amended ABI, and call it 3.1bis .

Speaking for myself, as a GCC user mainly for this, I feel it a lot clearer
to stick to the "minor releases only fix bugs but are otherwise fully
compatible" scheme; thus it seems to me that to avoid end user brain damage,
if a release with an ABI that we may reasonably expect to be compatible with
upcoming releases (but need to be incompatible with the currently almost
released 3.1.1) then it should be named 3.2.

Then what was for now named 3.2 byt GCC *developpers* (a much smaller
community than gcc *users*) may have to be renamed 3.3 if there is
incompatibilities with this 3.2 release (or major change in features), but
may just become 3.2.1 otherwise. 

In all cases the numbering scheme will then remain coherent and easily
understandable by users.

Just my .02$

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Saturday, July 06, 2002 10:47 PM
> To: Gabriel Dos Reis; gcc@gcc.gnu.org
> Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> > Thanks for the clarifications.  So all that needs is to make an
> > exception to our earlier commitment that minor releases won't
> > introduce ABI incompatibility; or make an exception to our scheduled
> > development plan.  I don't have any strong opinion.  But if we were
> 
> Well, we could could make a sub-branch from the 3.1 branch for the
> amended ABI, and call it 3.1bis .

Speaking for myself, as a GCC user mainly for this, I feel it a lot clearer
to stick to the "minor releases only fix bugs but are otherwise fully
compatible" scheme; thus it seems to me that to avoid end user brain damage,
if a release with an ABI that we may reasonably expect to be compatible with
upcoming releases (but need to be incompatible with the currently almost
released 3.1.1) then it should be named 3.2.

Then what was for now named 3.2 byt GCC *developpers* (a much smaller
community than gcc *users*) may have to be renamed 3.3 if there is
incompatibilities with this 3.2 release (or major change in features), but
may just become 3.2.1 otherwise. 

In all cases the numbering scheme will then remain coherent and easily
understandable by users.

Just my .02$

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Iain McClatchie]

Isn't this issue pretty obvious?

- All the major distributions want to go with something similar
  to the 3.1.1 code base, since it's well tested.

- All the major distributions want to avoid ABI changes

- ABI changes involve bumping the major rev number

- Big changes that don't touch the ABI also bump the major rev.

- The major distributions represent a very important segment of
  the GCC user community.

So you add the ABI change to 3.1.1 and call that 3.2.  This
is what all the major distributions want to ship, so they are
well incented to test the hell out of it.

What you had been calling 3.2 gets called 3.3.  Yes, it's too
bad that 3.2 won't be as great as you'd been hoping, but...
let it go.  The important thing is that as many users as
possible get as much of the great work you folks have been
doing as soon as possible.

So 3.2 won't be so great, but you won't be working on it very
long either.  FSF adopts the responsibility to maintain the 3.2
codeline, producing 3.2.1, 3.2.2, etc, as the distros feed back
fixes for the inevitable problems.  But you'll end up shifting
your focus to 3.3 very quickly.

Names aren't very important.  What is important is whether the
FSF crowd are going to take on significant extra management labors
in order to deliver a stable ABI for a while.  Yes, making a 3.2
which exists mostly to incorporate distro bugfixes is not very
grand, but it serves many users very well, and those same users
will have a much easier time upgrading to 3.3 later.

And that means that more people will get more of your good work
sooner.

-Iain McClatchie                       iain-3@truecircuits.com
                                       650-691-7604 voice
True Circuits, Inc.                    650-691-7606 FAX
                                       650-703-2095 cell

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Ben Woodhead]

Hello everybody.. 

If I remember correctly I believe that:
gcc x.y.z is 
x. Major  - Architecture Changes, 
y. Minor - Features added but no major architecture changes (slight changes to 
the abi could be possible here, if there are a small number of cases were it 
would affect). 
z. Patch - Patch levels are for overflows, nothing on the outside changes but 
possible bugs, such as not testing values, or overflows or fence post errors.

With that out of the way I find it really hard to see an abi change going into 
a patch level. Please, please please don't do that, 3.1.whatever should all 
match.. When talking about the version i should not have to say 3.1.1 because 
it should have only fixed segfaults and things like that, so the output and 
input should be the same, so 3.1 is fine.. 

As far as if this version is closer to version 3.1 or 3.2.. 3.2 does not exist 
so it can be what ever i want it to be.. ie, you could patch a text file in 
3.1 and call it 3.2 and theres nothing anybody can say about it. 

Just a possible suggestion, release 3.1.1 now the way it is, (on its release 
date) so the people using 3.1 can get the fixes they need. Then apply the abi 
changes, and test the output, try to find all the abi inconsistencies.. Then 
in August release version 3.1.1 with abi changes included as 3.2. 

That  way you don't have to worry about applying a patch a week way from the 
release date or making incompatabilities with 3.1.x. Also on the same not you 
don't have to try to release 3.2 with all the new features that are not well 
tested.. Everybodies is happy, the abi changes are in, and you don't have to 
worry about the experamental stuff from 3.2. 

Thanks, 
Ben Woodhead


Gabriel Dos Reis wrote:
> | Well, we could could make a sub-branch from the 3.1 branch for the
> | amended ABI, and call it 3.1bis .
> 
> Isn't that going to make some confusion? (That isn't meant to be
> rhetorical, that is a serious question)

Well, it should generate less confusion than calling it 3.2.x or 3.1.x,
since it is clear that it is closer to 3.1 than to 3.2, but not the
original 3.1 .  It's the second attempt to have a workable 3.1 .
        
-- 
--------------------------
SuperH
2430 Aztec West / Almondsbury / BRISTOL / BS32 4AQ
T:+44 1454 462330

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Monday, July 08, 2002 1:37 PM
> To: Bernard Dautrevaux
> Cc: Gabriel Dos Reis; gcc@gcc.gnu.org; Jakub@superh.com;
> Jelinek@superh.com; Mark Mitchell; obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> Bernard Dautrevaux wrote:
> > 
> > > -----Original Message-----
> > > From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> > > Sent: Saturday, July 06, 2002 10:47 PM
> > > To: Gabriel Dos Reis; gcc@gcc.gnu.org
> > > Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> > > obrien@freebsd.org
> > > Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> > >
> > >
> > > > Thanks for the clarifications.  So all that needs is to make an
> > > > exception to our earlier commitment that minor releases won't
> > > > introduce ABI incompatibility; or make an exception to 
> our scheduled
> > > > development plan.  I don't have any strong opinion.  
> But if we were
> > >
> > Then what was for now named 3.2 byt GCC *developpers* (a 
> much smaller
> > community than gcc *users*) may have to be renamed 3.3 if there is
> > incompatibilities with this 3.2 release (or major change in 
> features), but
> > may just become 3.2.1 otherwise.
> 
> But then you'd have a massive amount of new. possibly 
> destabilizing code
> in 3.2.1 versus 3.2.  Users generally expect a x.y.1 release 
> to me more
> stable than the preceding x.y.0 release.

So the "current" 3.2 branch should provide a 3.3 "release"...

> 
> And, on the other hand, 3.2 would be rather a disappointment regarding
> new features and ports.

I expect a 3.2 version with few new features and ports available soon, with
due comments on why it was done, be less disapointing than one done later
that add new features but also break compatibility. 

With a 
	3.2 == new ABI soon
	3.3 == new features later
split users can switch either now to the new ABI, or later to get both.

With the current scheme they just have
	3.2 == new ABI and new features
but this will only be availabel at the time the 3.3 of the previous scheme
will be. It seems that splitting th eevolution may be less destabilizing for
users and not too much added work for the developpers (not counting the
release manager which obvioulsy will have more work).

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Monday, July 08, 2002 1:37 PM
> To: Bernard Dautrevaux
> Cc: Gabriel Dos Reis; gcc@gcc.gnu.org; Jakub@superh.com;
> Jelinek@superh.com; Mark Mitchell; obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> Bernard Dautrevaux wrote:
> > 
> > > -----Original Message-----
> > > From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> > > Sent: Saturday, July 06, 2002 10:47 PM
> > > To: Gabriel Dos Reis; gcc@gcc.gnu.org
> > > Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> > > obrien@freebsd.org
> > > Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> > >
> > >
> > > > Thanks for the clarifications.  So all that needs is to make an
> > > > exception to our earlier commitment that minor releases won't
> > > > introduce ABI incompatibility; or make an exception to 
> our scheduled
> > > > development plan.  I don't have any strong opinion.  
> But if we were
> > >
> > Then what was for now named 3.2 byt GCC *developpers* (a 
> much smaller
> > community than gcc *users*) may have to be renamed 3.3 if there is
> > incompatibilities with this 3.2 release (or major change in 
> features), but
> > may just become 3.2.1 otherwise.
> 
> But then you'd have a massive amount of new. possibly 
> destabilizing code
> in 3.2.1 versus 3.2.  Users generally expect a x.y.1 release 
> to me more
> stable than the preceding x.y.0 release.

So the "current" 3.2 branch should provide a 3.3 "release"...

> 
> And, on the other hand, 3.2 would be rather a disappointment regarding
> new features and ports.

I expect a 3.2 version with few new features and ports available soon, with
due comments on why it was done, be less disapointing than one done later
that add new features but also break compatibility. 

With a 
	3.2 == new ABI soon
	3.3 == new features later
split users can switch either now to the new ABI, or later to get both.

With the current scheme they just have
	3.2 == new ABI and new features
but this will only be availabel at the time the 3.3 of the previous scheme
will be. It seems that splitting th eevolution may be less destabilizing for
users and not too much added work for the developpers (not counting the
release manager which obvioulsy will have more work).

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Monday, July 08, 2002 1:37 PM
> To: Bernard Dautrevaux
> Cc: Gabriel Dos Reis; gcc@gcc.gnu.org; Jakub@superh.com;
> Jelinek@superh.com; Mark Mitchell; obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> Bernard Dautrevaux wrote:
> > 
> > > -----Original Message-----
> > > From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> > > Sent: Saturday, July 06, 2002 10:47 PM
> > > To: Gabriel Dos Reis; gcc@gcc.gnu.org
> > > Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> > > obrien@freebsd.org
> > > Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> > >
> > >
> > > > Thanks for the clarifications.  So all that needs is to make an
> > > > exception to our earlier commitment that minor releases won't
> > > > introduce ABI incompatibility; or make an exception to 
> our scheduled
> > > > development plan.  I don't have any strong opinion.  
> But if we were
> > >
> > Then what was for now named 3.2 byt GCC *developpers* (a 
> much smaller
> > community than gcc *users*) may have to be renamed 3.3 if there is
> > incompatibilities with this 3.2 release (or major change in 
> features), but
> > may just become 3.2.1 otherwise.
> 
> But then you'd have a massive amount of new. possibly 
> destabilizing code
> in 3.2.1 versus 3.2.  Users generally expect a x.y.1 release 
> to me more
> stable than the preceding x.y.0 release.

So the "current" 3.2 branch should provide a 3.3 "release"...

> 
> And, on the other hand, 3.2 would be rather a disappointment regarding
> new features and ports.

I expect a 3.2 version with few new features and ports available soon, with
due comments on why it was done, be less disapointing than one done later
that add new features but also break compatibility. 

With a 
	3.2 == new ABI soon
	3.3 == new features later
split users can switch either now to the new ABI, or later to get both.

With the current scheme they just have
	3.2 == new ABI and new features
but this will only be availabel at the time the 3.3 of the previous scheme
will be. It seems that splitting th eevolution may be less destabilizing for
users and not too much added work for the developpers (not counting the
release manager which obvioulsy will have more work).

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Monday, July 08, 2002 1:37 PM
> To: Bernard Dautrevaux
> Cc: Gabriel Dos Reis; gcc@gcc.gnu.org; Jakub@superh.com;
> Jelinek@superh.com; Mark Mitchell; obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> Bernard Dautrevaux wrote:
> > 
> > > -----Original Message-----
> > > From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> > > Sent: Saturday, July 06, 2002 10:47 PM
> > > To: Gabriel Dos Reis; gcc@gcc.gnu.org
> > > Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> > > obrien@freebsd.org
> > > Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> > >
> > >
> > > > Thanks for the clarifications.  So all that needs is to make an
> > > > exception to our earlier commitment that minor releases won't
> > > > introduce ABI incompatibility; or make an exception to 
> our scheduled
> > > > development plan.  I don't have any strong opinion.  
> But if we were
> > >
> > Then what was for now named 3.2 byt GCC *developpers* (a 
> much smaller
> > community than gcc *users*) may have to be renamed 3.3 if there is
> > incompatibilities with this 3.2 release (or major change in 
> features), but
> > may just become 3.2.1 otherwise.
> 
> But then you'd have a massive amount of new. possibly 
> destabilizing code
> in 3.2.1 versus 3.2.  Users generally expect a x.y.1 release 
> to me more
> stable than the preceding x.y.0 release.

So the "current" 3.2 branch should provide a 3.3 "release"...

> 
> And, on the other hand, 3.2 would be rather a disappointment regarding
> new features and ports.

I expect a 3.2 version with few new features and ports available soon, with
due comments on why it was done, be less disapointing than one done later
that add new features but also break compatibility. 

With a 
	3.2 == new ABI soon
	3.3 == new features later
split users can switch either now to the new ABI, or later to get both.

With the current scheme they just have
	3.2 == new ABI and new features
but this will only be availabel at the time the 3.3 of the previous scheme
will be. It seems that splitting th eevolution may be less destabilizing for
users and not too much added work for the developpers (not counting the
release manager which obvioulsy will have more work).

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Bernard Dautrevaux]

> -----Original Message-----
> From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> Sent: Monday, July 08, 2002 1:37 PM
> To: Bernard Dautrevaux
> Cc: Gabriel Dos Reis; gcc@gcc.gnu.org; Jakub@superh.com;
> Jelinek@superh.com; Mark Mitchell; obrien@freebsd.org
> Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> 
> 
> Bernard Dautrevaux wrote:
> > 
> > > -----Original Message-----
> > > From: Joern Rennecke [mailto:joern.rennecke@superh.com]
> > > Sent: Saturday, July 06, 2002 10:47 PM
> > > To: Gabriel Dos Reis; gcc@gcc.gnu.org
> > > Cc: Jakub@superh.com; Jelinek@superh.com; Mark Mitchell;
> > > obrien@freebsd.org
> > > Subject: Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?
> > >
> > >
> > > > Thanks for the clarifications.  So all that needs is to make an
> > > > exception to our earlier commitment that minor releases won't
> > > > introduce ABI incompatibility; or make an exception to 
> our scheduled
> > > > development plan.  I don't have any strong opinion.  
> But if we were
> > >
> > Then what was for now named 3.2 byt GCC *developpers* (a 
> much smaller
> > community than gcc *users*) may have to be renamed 3.3 if there is
> > incompatibilities with this 3.2 release (or major change in 
> features), but
> > may just become 3.2.1 otherwise.
> 
> But then you'd have a massive amount of new. possibly 
> destabilizing code
> in 3.2.1 versus 3.2.  Users generally expect a x.y.1 release 
> to me more
> stable than the preceding x.y.0 release.

So the "current" 3.2 branch should provide a 3.3 "release"...

> 
> And, on the other hand, 3.2 would be rather a disappointment regarding
> new features and ports.

I expect a 3.2 version with few new features and ports available soon, with
due comments on why it was done, be less disapointing than one done later
that add new features but also break compatibility. 

With a 
	3.2 == new ABI soon
	3.3 == new features later
split users can switch either now to the new ABI, or later to get both.

With the current scheme they just have
	3.2 == new ABI and new features
but this will only be availabel at the time the 3.3 of the previous scheme
will be. It seems that splitting th eevolution may be less destabilizing for
users and not too much added work for the developpers (not counting the
release manager which obvioulsy will have more work).

        Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux@microprocess.com
-------------------------------------------- 

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Joern Rennecke]

> Thanks for the clarifications.  So all that needs is to make an
> exception to our earlier commitment that minor releases won't
> introduce ABI incompatibility; or make an exception to our scheduled
> development plan.  I don't have any strong opinion.  But if we were

Well, we could could make a sub-branch from the 3.1 branch for the
amended ABI, and call it 3.1bis .

-- 
--------------------------
SuperH
2430 Aztec West / Almondsbury / BRISTOL / BS32 4AQ
T:+44 1454 462330

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Gabriel Dos Reis]

Joern Rennecke <joern.rennecke@superh.com> writes:

| > Thanks for the clarifications.  So all that needs is to make an
| > exception to our earlier commitment that minor releases won't
| > introduce ABI incompatibility; or make an exception to our scheduled
| > development plan.  I don't have any strong opinion.  But if we were
| 
| Well, we could could make a sub-branch from the 3.1 branch for the
| amended ABI, and call it 3.1bis .

Isn't that going to make some confusion? (That isn't meant to be
rhetorical, that is a serious question) 

-- Gaby

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Joern Rennecke]

Gabriel Dos Reis wrote:
> | Well, we could could make a sub-branch from the 3.1 branch for the
> | amended ABI, and call it 3.1bis .
> 
> Isn't that going to make some confusion? (That isn't meant to be
> rhetorical, that is a serious question)

Well, it should generate less confusion than calling it 3.2.x or 3.1.x,
since it is clear that it is closer to 3.1 than to 3.2, but not the
original 3.1 .  It's the second attempt to have a workable 3.1 .
	
-- 
--------------------------
SuperH
2430 Aztec West / Almondsbury / BRISTOL / BS32 4AQ
T:+44 1454 462330

C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Andreas Jaeger]

Jason committed recently patch to fix a number of C++ Bugs in the ABI:
http://gcc.gnu.org/ml/gcc-patches/2002-06/msg01275.html

What does this mean for binary compatibility between GCC 3.1 and GCC
3.2?  With the introduction of GCC 3 and its ABI, the expectation by
users is that we won't have binary incompatible changes.  Unfortunatly
the - AFAIK valid - bug reports show that the ABI implemention was
buggy and therefore needed to change.

What will this mean for distributions and for production usage of GCC
3.1?  I fear this means that folks cannot easily upgrade from GCC 3.1
to GCC 3.2 since C++ is incompatible and all C++ libraries that are
needed for development need to be relinked.

Would it make sense for a distribution starting to ship GCC 3.1 to
apply that bugfix?  I prefer not to do this since it would mean that
then two different GCC 3.1 release are binary incompatible :-(.  But
it would allow an easier upgrade to GCC 3.2 - or distributors are
stuck with GCC 3.1 like some where stuck with GCC 2.95 due to the
binary incompatibilities between 2.95, 3.0 and 3.1 which were known
before.

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[H. J. Lu]

On Thu, Jul 04, 2002 at 06:35:06PM +0200, Andreas Jaeger wrote:
> 
> Would it make sense for a distribution starting to ship GCC 3.1 to
> apply that bugfix?  I prefer not to do this since it would mean that

If it is true, those bug fixes should be moved into gcc 3.1 after
verifying they are really ok. At least, there should be a gcc 3
clearing house for Linux for those kinds of ABI issuses so that there
is a hope for a compatible C++ implememntation among different Linux
distributions.


H.J.

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Mark Mitchell]

> What does this mean for binary compatibility between GCC 3.1 and GCC
> 3.2?  With the introduction of GCC 3 and its ABI, the expectation by
> users is that we won't have binary incompatible changes.  Unfortunatly
> the - AFAIK valid - bug reports show that the ABI implemention was
> buggy and therefore needed to change.

Yes, the implementation had some bugs.  It was also the case that the
ABI specification had some bugs/omissions/unclarities.  (The most recent
substantive change to the ABI specification occurred about a week ago.)

There are getting to be fewer and fewer bugs and the rate of change to
the ABI is approaching zero, but I, like you, am disappointed that we're
still breaking the C++ ABI between major releases of the compiler.

In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
with respect to the C++ ABI.

I can't say what that might mean as a distributor.

--
Mark Mitchell                   mark@codesourcery.com
CodeSourcery, LLC               http://www.codesourcery.com

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Andreas Jaeger]

Mark Mitchell <mark@codesourcery.com> writes:

>> What does this mean for binary compatibility between GCC 3.1 and GCC
>> 3.2?  With the introduction of GCC 3 and its ABI, the expectation by
>> users is that we won't have binary incompatible changes.  Unfortunatly
>> the - AFAIK valid - bug reports show that the ABI implemention was
>> buggy and therefore needed to change.
>
> Yes, the implementation had some bugs.  It was also the case that the
> ABI specification had some bugs/omissions/unclarities.  (The most recent
> substantive change to the ABI specification occurred about a week ago.)
>
> There are getting to be fewer and fewer bugs and the rate of change to
> the ABI is approaching zero, but I, like you, am disappointed that we're
> still breaking the C++ ABI between major releases of the compiler.
>
> In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
> with respect to the C++ ABI.

How severe is this?  Will people encounter this in every day code or
is only in some esoteric situations?

> I can't say what that might mean as a distributor.

Putting on my distributor hat - and answering without much thinking
about all the implications - it would be better to have 3.1.1 and 3.2
compatible (with the cost of 3.1 and 3.1.1 not compatible to each
other).  Alternativly we could rename GCC 3.1.1 to GCC 3.2.1 and
release that in a few weeks time (this would imply to rename mainline
to GCC 3.3 prerelease and have GCC 3.3 release in autumn).

As you see, I haven't made my up mind and do not know what the best
solution is here.

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Mark Mitchell]

>> In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
>> with respect to the C++ ABI.
>
> How severe is this?  Will people encounter this in every day code or
> is only in some esoteric situations?

Questions like this are always difficult to answer.

I would lean towards "only in some esoteric situations", but of course
that depends on exactly what you consider esoteric.

>> I can't say what that might mean as a distributor.
>
> Putting on my distributor hat - and answering without much thinking
> about all the implications - it would be better to have 3.1.1 and 3.2
> compatible (with the cost of 3.1 and 3.1.1 not compatible to each
> other).

This bit has already been decided.  We will not break compatibility
between minor releases (3.1 and 3.1.1) unless it is absolutely
necessary.  I don't think renumbering is going to help a lot.

--
Mark Mitchell                   mark@codesourcery.com
CodeSourcery, LLC               http://www.codesourcery.com

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[David O'Brien]

On Fri, Jul 05, 2002 at 01:11:10PM -0700, Mark Mitchell wrote:
> >> In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
> >> with respect to the C++ ABI.
> > How severe is this?  Will people encounter this in every day code or
> > is only in some esoteric situations?
... 
> I would lean towards "only in some esoteric situations", but of course
> that depends on exactly what you consider esoteric.

Would we see it in KDE and GNOME and all the related C++ libs there?


> > it would be better to have 3.1.1 and 3.2 compatible (with the cost of
> > 3.1 and 3.1.1 not compatible to each other).
> 
> This bit has already been decided.  We will not break compatibility
> between minor releases (3.1 and 3.1.1) unless it is absolutely
> necessary.  I don't think renumbering is going to help a lot.

Why not put the decision in the hands of the distributors?  Offer both
3.1 and 3.2 C++ ABI's and let the vendor pick the one they want with a
#define.

I dare say all the distributors feel this way -- all the existing
versions out there use GCC 2.95.3[+], or the RedHat 2.96.  All of which
are binary incompatible with 3.x.  FreeBSD will be using 3.1.1 in our 5.0
release; and I've heard plans from some Linux distributions to use 3.1.1
in their next release also.

-- 
-- David    (obrien@FreeBSD.org)

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Mark Mitchell]

--On Friday, July 05, 2002 02:33:53 PM -0700 David O'Brien 
<obrien@freebsd.org> wrote:

> On Fri, Jul 05, 2002 at 01:11:10PM -0700, Mark Mitchell wrote:
>> >> In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
>> >> with respect to the C++ ABI.
>> > How severe is this?  Will people encounter this in every day code or
>> > is only in some esoteric situations?
> ...
>> I would lean towards "only in some esoteric situations", but of course
>> that depends on exactly what you consider esoteric.
>
> Would we see it in KDE and GNOME and all the related C++ libs there?

I don't think anybody knows.

>> > it would be better to have 3.1.1 and 3.2 compatible (with the cost of
>> > 3.1 and 3.1.1 not compatible to each other).
>>
>> This bit has already been decided.  We will not break compatibility
>> between minor releases (3.1 and 3.1.1) unless it is absolutely
>> necessary.  I don't think renumbering is going to help a lot.
>
> Why not put the decision in the hands of the distributors?  Offer both
> 3.1 and 3.2 C++ ABI's and let the vendor pick the one they want with a
># define.

Because our goal is to produce minor releases that fix critical bugs.

Adding in new, not nearly as well-tested ABI changes, one week for a
release is simply not going to happen.

--
Mark Mitchell                   mark@codesourcery.com
CodeSourcery, LLC               http://www.codesourcery.com

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Andreas Jaeger]

Mark Mitchell <mark@codesourcery.com> writes:

> --On Friday, July 05, 2002 02:33:53 PM -0700 David O'Brien
> <obrien@freebsd.org> wrote:
>
>> On Fri, Jul 05, 2002 at 01:11:10PM -0700, Mark Mitchell wrote:
>>> >> In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
>>> >> with respect to the C++ ABI.
>>> > How severe is this?  Will people encounter this in every day code or
>>> > is only in some esoteric situations?
>> ...
>>> I would lean towards "only in some esoteric situations", but of course
>>> that depends on exactly what you consider esoteric.
>>
>> Would we see it in KDE and GNOME and all the related C++ libs there?
>
> I don't think anybody knows.
>
>>> > it would be better to have 3.1.1 and 3.2 compatible (with the cost of
>>> > 3.1 and 3.1.1 not compatible to each other).
>>>
>>> This bit has already been decided.  We will not break compatibility
>>> between minor releases (3.1 and 3.1.1) unless it is absolutely
>>> necessary.  I don't think renumbering is going to help a lot.
>>
>> Why not put the decision in the hands of the distributors?  Offer both
>> 3.1 and 3.2 C++ ABI's and let the vendor pick the one they want with a
>># define.

That would mean incompatibility between 3.1. versions - my
self compiled 3.1.1 compiler would be incompatible to your
self-compiled 3.1.1 compiler :-(.

>
> Because our goal is to produce minor releases that fix critical bugs.
>
> Adding in new, not nearly as well-tested ABI changes, one week for a
> release is simply not going to happen.

What about postponing this change for 3.1.2 - with possible renaming
it to 3.2.2 - with the goal to be compatible to GCC mainline?

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Gabriel Dos Reis]

Andreas Jaeger <aj@suse.de> writes:

| > Because our goal is to produce minor releases that fix critical bugs.
| >
| > Adding in new, not nearly as well-tested ABI changes, one week for a
| > release is simply not going to happen.
| 
| What about postponing this change for 3.1.2 - 

That would make an ABI incompatibility in minor releases.  That is
worst than incompatibility between major releases.

| with possible renaming
| it to 3.2.2 - with the goal to be compatible to GCC mainline?

I raise the same objection.  Minor releases should not introduce ABI
incompatibilities.  They should just feature non-ABI breaking bug
fixes.

-- Gaby

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Jakub Jelinek]

On Sat, Jul 06, 2002 at 02:32:55PM +0200, Gabriel Dos Reis wrote:
> | > Because our goal is to produce minor releases that fix critical bugs.
> | >
> | > Adding in new, not nearly as well-tested ABI changes, one week for a
> | > release is simply not going to happen.
> | 
> | What about postponing this change for 3.1.2 - 
> 
> That would make an ABI incompatibility in minor releases.  That is
> worst than incompatibility between major releases.
> 
> | with possible renaming
> | it to 3.2.2 - with the goal to be compatible to GCC mainline?
> 
> I raise the same objection.  Minor releases should not introduce ABI
> incompatibilities.  They should just feature non-ABI breaking bug
> fixes.

But if 3.1.2 was called 3.2, it would not be minor release but major, thus
could introduce ABI incompatibilities.
Apple could stay at 3.1, while Linux vendors, FreeBSD and whoever
is currently preparing 3.1.x based distribution could still switch to this
3.2 and be (hopefully) binary compatible with the upcoming 3.3 
(current trunk).

	Jakub

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Gabriel Dos Reis]

Jakub Jelinek <jakub@redhat.com> writes:

| But if 3.1.2 was called 3.2, it would not be minor release but major, thus
| could introduce ABI incompatibilities.

As I understand people are objecting to having 3.1.x not binrary
compatible with 3.2.y.

| Apple could stay at 3.1, while Linux vendors, FreeBSD and whoever
| is currently preparing 3.1.x based distribution could still switch to this
| 3.2 and be (hopefully) binary compatible with the upcoming 3.3 
| (current trunk).

-- Gaby

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Andreas Jaeger]

Gabriel Dos Reis <gdr@codesourcery.com> writes:

> Jakub Jelinek <jakub@redhat.com> writes:
>
> | But if 3.1.2 was called 3.2, it would not be minor release but major, thus
> | could introduce ABI incompatibilities.
>
> As I understand people are objecting to having 3.1.x not binrary
> compatible with 3.2.y.

The problem is that people are soon going to use 3.1.x in production
environments.  If we switch today to 3.1, we're stuck with it, since
it will be binary incompatible to later versions.  But if a release
[1] from the 3.1 branch happens that ensures binary compatibilty with
later GCC versions - and this happens in the next few weeks, I expect
that the communities can switch to that version.  This should solve at
least the problems I have at SuSE.

Andreas

Footnotes: 
[1]  Note I don't give a version number here.

-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Gabriel Dos Reis]

Andreas Jaeger <aj@suse.de> writes:

| Gabriel Dos Reis <gdr@codesourcery.com> writes:
| 
| > Jakub Jelinek <jakub@redhat.com> writes:
| >
| > | But if 3.1.2 was called 3.2, it would not be minor release but major, thus
| > | could introduce ABI incompatibilities.
| >
| > As I understand people are objecting to having 3.1.x not binrary
| > compatible with 3.2.y.
| 
| The problem is that people are soon going to use 3.1.x in production
| environments.  If we switch today to 3.1, we're stuck with it, since
| it will be binary incompatible to later versions.  But if a release
| [1] from the 3.1 branch happens that ensures binary compatibilty with
| later GCC versions - and this happens in the next few weeks, I expect
| that the communities can switch to that version.  This should solve at
| least the problems I have at SuSE.

Thanks for the clarifications.  So all that needs is to make an
exception to our earlier commitment that minor releases won't
introduce ABI incompatibility; or make an exception to our scheduled
development plan.  I don't have any strong opinion.  But if we were
not to follow our developement schedule (as proposed by Jakub) we
have better to be sure that nearly all ABI bugs are fixed in 3.2 (or
we will face the same problem later).  Given the time-frame I'm not
sure we have enought latitude to do that...

-- Gaby

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Daniel Jacobowitz]

On Sat, Jul 06, 2002 at 03:44:35PM +0200, Andreas Jaeger wrote:
> Gabriel Dos Reis <gdr@codesourcery.com> writes:
> 
> > Jakub Jelinek <jakub@redhat.com> writes:
> >
> > | But if 3.1.2 was called 3.2, it would not be minor release but major, thus
> > | could introduce ABI incompatibilities.
> >
> > As I understand people are objecting to having 3.1.x not binrary
> > compatible with 3.2.y.
> 
> The problem is that people are soon going to use 3.1.x in production
> environments.  If we switch today to 3.1, we're stuck with it, since
> it will be binary incompatible to later versions.  But if a release
> [1] from the 3.1 branch happens that ensures binary compatibilty with
> later GCC versions - and this happens in the next few weeks, I expect
> that the communities can switch to that version.  This should solve at
> least the problems I have at SuSE.
> 
> Andreas
> 
> Footnotes: 
> [1]  Note I don't give a version number here.

On the Debian side, we're starting to organize a move from gcc 2.95 to
a 3.1-branch compiler as the system compiler, with hopes to do it in
the next couple of months.  Changing compilers in such a way as to
break the C++ ABI is a gargantuan effort for a continually-updating
system like Debian's unstable distribution, and I expect it to be a
very painful process.  Not something I want to do more than once.

On the other hand, I'm not terribly concerned here.  These sound like
bugs which we can easily resolve on a case-by-case basis if they
actually manifest in a given library's interfaces, rare enough that we
won't need the sort of all-at-once effort that v2->v3 is going to
require.

[I speak for no man and no company]

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Andreas Jaeger]

Jakub Jelinek <jakub@redhat.com> writes:

> On Sat, Jul 06, 2002 at 02:32:55PM +0200, Gabriel Dos Reis wrote:
>> | > Because our goal is to produce minor releases that fix critical bugs.
>> | >
>> | > Adding in new, not nearly as well-tested ABI changes, one week for a
>> | > release is simply not going to happen.
>> | 
>> | What about postponing this change for 3.1.2 - 
>> 
>> That would make an ABI incompatibility in minor releases.  That is
>> worst than incompatibility between major releases.
>> 
>> | with possible renaming
>> | it to 3.2.2 - with the goal to be compatible to GCC mainline?
>> 
>> I raise the same objection.  Minor releases should not introduce ABI
>> incompatibilities.  They should just feature non-ABI breaking bug
>> fixes.
>
> But if 3.1.2 was called 3.2, it would not be minor release but major, thus
> could introduce ABI incompatibilities.
> Apple could stay at 3.1, while Linux vendors, FreeBSD and whoever
> is currently preparing 3.1.x based distribution could still switch to this
> 3.2 and be (hopefully) binary compatible with the upcoming 3.3 
> (current trunk).

I agree with you, Jakub.

Who would be interested in such a switch?  FreeBSD and SuSE seem to be
interested.  What about Linux distributors, e.g. Red Hat and other
OSes?

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Jeff Law]

 In message <u8y9cprn65.fsf@gromit.moeb>, Andreas Jaeger writes:
 >Jakub Jelinek <jakub@redhat.com> writes:
 >I agree with you, Jakub.
 >
 >Who would be interested in such a switch?  FreeBSD and SuSE seem to be
 >interested.  What about Linux distributors, e.g. Red Hat and other
 >OSes?
We're definitely interested.  And like SuSE, if we could get the bits in
July they would be useful, if they don't arrive until September, then they
would not be useful. 

jeff

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Gwenole Beauchesne]

Hi,

>  In message <u8y9cprn65.fsf@gromit.moeb>, Andreas Jaeger writes:
>> Jakub Jelinek <jakub@redhat.com> writes:
>> I agree with you, Jakub.
>>
>> Who would be interested in such a switch?  FreeBSD and SuSE seem to be
>> interested.  What about Linux distributors, e.g. Red Hat and other
>> OSes?
> We're definitely interested.  And like SuSE, if we could get the bits in
> July they would be useful, if they don't arrive until September, then 
> they
> would not be useful.

Likewise to Red Hat and SuSE, we are interested in those changes/switch 
too. And September would be too late as well.

Bye,
Gwenole, sorry to aol'izing.

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Daniel Egger]

Am Fre, 2002-07-05 um 23.33 schrieb David O'Brien:

> Would we see it in KDE and GNOME and all the related C++ libs there?

You can trivially count the GNOME applications and libraries written in
C++ with your hands. KDE might be much more of a problem here
escpecially since they're driving gcc at its maximum in the hope to
get fast and small binaries.
 
-- 
Servus,
       Daniel

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[David O'Brien]

On Fri, Jul 05, 2002 at 12:51:17PM -0700, Mark Mitchell wrote:
> In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
> with respect to the C++ ABI.
> 
> I can't say what that might mean as a distributor.

I can -- MAJOR pain and difficulty.  It would probably prevent FreeBSD
using GCC 3.2 in our 5.1 and later 5.x releases.  That means 1-2 years
before the compiler can be upgraded for our users.

I urge you as strongly as I can to back port (#define wrap if needed) the
changes so that GCC 3.1.1 can be built to be 100% C++ ABI compatible with
GCC 3.2.  FreeBSD can much more easily accept breakage between 3.1[.0]
and 3.1.1, than between 3.1.1 and 3.2[.0] as we are still developing 5.0
and can take ABI hits right now.
 
-- 
-- David    (obrien@FreeBSD.org)

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Mark Mitchell]

--On Friday, July 05, 2002 02:28:38 PM -0700 David O'Brien 
<obrien@FreeBSD.org> wrote:

> On Fri, Jul 05, 2002 at 12:51:17PM -0700, Mark Mitchell wrote:
>> In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
>> with respect to the C++ ABI.
>>
>> I can't say what that might mean as a distributor.
>
> I can -- MAJOR pain and difficulty.  It would probably prevent FreeBSD
> using GCC 3.2 in our 5.1 and later 5.x releases.  That means 1-2 years
> before the compiler can be upgraded for our users.
>
> I urge you as strongly as I can to back port (#define wrap if needed) the
> changes so that GCC 3.1.1 can be built to be 100% C++ ABI compatible with
> GCC 3.2.  FreeBSD can much more easily accept breakage between 3.1[.0]
> and 3.1.1, than between 3.1.1 and 3.2[.0] as we are still developing 5.0
> and can take ABI hits right now.

It's not the job of the FSF maintainers to do this.

If FreeBSD wants to backport patches, for its version, that's fine.
My goal, as RM, is for FSF users to be able to go from 3.1 to 3.1.1
without difficulty.

(The point of the minor releases is to fix critical bugs.)

We can't possibly know when we release 3.1.1 -- soon -- what changes may
or not be in 3.2 -- which is still months away.

I, of all people, appreciate the importance of binary compatibility
in C++.  There's really very little we can do, other than trying to
find and fix all the problems.

--
Mark Mitchell                   mark@codesourcery.com
CodeSourcery, LLC               http://www.codesourcery.com

RE: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Scott Robert Ladd]

Perhaps I'm a bit out-of-line by dropping into this debate, but I see some
nasty trends that are "bad" for the entire free software movement.

MM> Because our goal is to produce minor releases
MM> that fix critical bugs.

How does the above statement play with something Mark Mitchell said in an
earlier post:

MM> Yes, the implementation had some bugs.  It was
MM> also the case that the ABI specification had some
MM> bugs/omissions/unclarities.

If the ABI specification is buggy, shouldn't such "bugs" be fixed in an
interim release, i.e., 3.1.1?

The ABI is fundamental, and if changes must be made, sooner is far better
than later.

MM> It's not the job of the FSF maintainers to do this.

I submit that this may be true in an absolute sense, but such an attitude
fails to recognize the importance of gcc. gcc is the foundation of free and
open software; if that foundation keeps shifting, it increases risk and
stress for those building upon it.

MM> Adding in new, not nearly as well-tested ABI changes,
MM> one week for a release is simply not going to happen.

The perhaps the release schedule is unrealistic?

..Scott
(Who'd love to help with gcc if he could figure out where to stick his
nose...)

Scott Robert Ladd
Coyote Gulch Productions,  http://www.coyotegulch.com
No ads -- just very free (and somewhat unusual) code.

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[H. J. Lu]

On Fri, Jul 05, 2002 at 02:28:38PM -0700, David O'Brien wrote:
> On Fri, Jul 05, 2002 at 12:51:17PM -0700, Mark Mitchell wrote:
> > In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
> > with respect to the C++ ABI.
> > 
> > I can't say what that might mean as a distributor.
> 
> I can -- MAJOR pain and difficulty.  It would probably prevent FreeBSD
> using GCC 3.2 in our 5.1 and later 5.x releases.  That means 1-2 years
> before the compiler can be upgraded for our users.
> 
> I urge you as strongly as I can to back port (#define wrap if needed) the
> changes so that GCC 3.1.1 can be built to be 100% C++ ABI compatible with
> GCC 3.2.  FreeBSD can much more easily accept breakage between 3.1[.0]
> and 3.1.1, than between 3.1.1 and 3.2[.0] as we are still developing 5.0
> and can take ABI hits right now.
>  

IMHO, keep the C++ ABI compatibility between 3.1 and 3.1.x, but break
between 3.1.x and 3.2, is one of the worst things anyone can do to gcc.


H.J.

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[David O'Brien]

On Fri, Jul 05, 2002 at 02:35:34PM -0700, H. J. Lu wrote:
> IMHO, keep the C++ ABI compatibility between 3.1 and 3.1.x, but break
> between 3.1.x and 3.2, is one of the worst things anyone can do to gcc.

Why?  Both Andreas said that the change happening 3.1.1->3.2 will cause
problems in upcoming OS releases.  You didn't give any reasoning for your
position.

-- 
-- David    (obrien@FreeBSD.org)

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[H. J. Lu]

On Fri, Jul 05, 2002 at 02:46:11PM -0700, David O'Brien wrote:
> On Fri, Jul 05, 2002 at 02:35:34PM -0700, H. J. Lu wrote:
> > IMHO, keep the C++ ABI compatibility between 3.1 and 3.1.x, but break
> > between 3.1.x and 3.2, is one of the worst things anyone can do to gcc.
> 
> Why?  Both Andreas said that the change happening 3.1.1->3.2 will cause
> problems in upcoming OS releases.  You didn't give any reasoning for your
> position.

My position is I doubt many people really case the C++ ABI compatibility
between 3.1 and 3.1.1, at least I don't. I can even pretend 3.1 never
existed :-(.


H.J.

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Stan Shebs]

"H. J. Lu" wrote:
> 
> On Fri, Jul 05, 2002 at 02:46:11PM -0700, David O'Brien wrote:
> > On Fri, Jul 05, 2002 at 02:35:34PM -0700, H. J. Lu wrote:
> > > IMHO, keep the C++ ABI compatibility between 3.1 and 3.1.x, but break
> > > between 3.1.x and 3.2, is one of the worst things anyone can do to gcc.
> >
> > Why?  Both Andreas said that the change happening 3.1.1->3.2 will cause
> > problems in upcoming OS releases.  You didn't give any reasoning for your
> > position.
> 
> My position is I doubt many people really case the C++ ABI compatibility
> between 3.1 and 3.1.1, at least I don't. I can even pretend 3.1 never
> existed :-(.

Apple is going to care a lot.  Jaguar is all based on 3.1, and it's
likely that some developer tool releases are going to use 3.1.1 or
later, in which case it's imperative that 3.1 and 3.1.x all be
binary compatible.

3.2 is a ways off still, who knows what kind of compatibility it
will have in the end.  It's even possible that we or somebody else
will work up a patch to provide a runtime choice between 3.1 and
3.2 ABI - Apple's GCC already has terrible ugly patches to optionally
emulate parts of the 2.95 ABI, but they (along with some ugly kernel
hackery) make it possible for existing 0S X 10.1 drivers to "just work"
on Jaguar, so they're worth the extra trouble.

Stan

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[David Edelsohn]

	I thought that after GCC 3.1 was released, C++ bugs were suppose
to be fixed in a backward-compatible way not requiring incompatible
changes in the ABI, even if that required extra work.

David

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Stan Shebs]

David Edelsohn wrote:
> 
>         I thought that after GCC 3.1 was released, C++ bugs were suppose
> to be fixed in a backward-compatible way not requiring incompatible
> changes in the ABI, even if that required extra work.

If 3.1's output is inadvertantly different from what the ABI
prescribes, then either you do nothing and be incompatible with
the ABI (and other compilers), or you change the compiler and
make 3.2 incompatible with 3.1.  The only possible extra work I
can think of for this conundrum is to add a -fabi-3.1 flag that
sacrifices strict ABI compliance so as to match 3.1.

Stan

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Geoff Keating]

David Edelsohn <dje@watson.ibm.com> writes:

> 	I thought that after GCC 3.1 was released, C++ bugs were suppose
> to be fixed in a backward-compatible way not requiring incompatible
> changes in the ABI, even if that required extra work.

I don't believe that's possible in this case.  Of the three bugs I've
seen referenced, two are layout problems; there's no way to be
compatible if GCC currently expects a field to be in one place and the
ABI requires it to be in another, especially if the two places overlap.

-- 
- Geoffrey Keating <geoffk@geoffk.org> <geoffk@redhat.com>

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Mark Mitchell]

--On Friday, July 05, 2002 06:12:28 PM -0400 David Edelsohn 
<dje@watson.ibm.com> wrote:

> 	I thought that after GCC 3.1 was released, C++ bugs were suppose
> to be fixed in a backward-compatible way not requiring incompatible
> changes in the ABI, even if that required extra work.

When that's possible, that might make sense.

In the cases we've run into so far, it hasn't been possible, regardless
of how much work you put into it.

-- 
Mark Mitchell                mark@codesourcery.com
CodeSourcery, LLC            http://www.codesourcery.com

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Andreas Jaeger]

"David O'Brien" <obrien@FreeBSD.org> writes:

> On Fri, Jul 05, 2002 at 12:51:17PM -0700, Mark Mitchell wrote:
>> In any case, GCC 3.1 and GCC 3.2 will not be 100% binary compatible
>> with respect to the C++ ABI.
>> 
>> I can't say what that might mean as a distributor.
>
> I can -- MAJOR pain and difficulty.  It would probably prevent FreeBSD
> using GCC 3.2 in our 5.1 and later 5.x releases.  That means 1-2 years
> before the compiler can be upgraded for our users.

The same for most Linux distributors if they go with 3.1.x - and I
know that some will go, including SuSE.

>
> I urge you as strongly as I can to back port (#define wrap if needed) the
> changes so that GCC 3.1.1 can be built to be 100% C++ ABI compatible with
> GCC 3.2.  FreeBSD can much more easily accept breakage between 3.1[.0]
> and 3.1.1, than between 3.1.1 and 3.2[.0] as we are still developing 5.0
> and can take ABI hits right now.

The same applies for SuSE and possible also other distributors,

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Gerald Pfeifer]

On Sat, 6 Jul 2002, Andreas Jaeger wrote:
>> I urge you as strongly as I can to back port (#define wrap if needed) the
>> changes so that GCC 3.1.1 can be built to be 100% C++ ABI compatible with
>> GCC 3.2.  FreeBSD can much more easily accept breakage between 3.1[.0]
>> and 3.1.1, than between 3.1.1 and 3.2[.0] as we are still developing 5.0
>> and can take ABI hits right now.
> The same applies for SuSE and possible also other distributors,

What's the cut-off date where you (Andreas, David,...) would need to
have a release of GCC with such a C++ ABI change?

There are strong arguments not to make this change for 3.1.1 which is
due quite soon, but that doesn't prevent us from making another release
shortly thereafter, for example.

Gerald
-- 
Gerald "Jerry" pfeifer@dbai.tuwien.ac.at http://www.dbai.tuwien.ac.at/~pfeifer/

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Andreas Jaeger]

Gerald Pfeifer <pfeifer@dbai.tuwien.ac.at> writes:

> On Sat, 6 Jul 2002, Andreas Jaeger wrote:
>>> I urge you as strongly as I can to back port (#define wrap if needed) the
>>> changes so that GCC 3.1.1 can be built to be 100% C++ ABI compatible with
>>> GCC 3.2.  FreeBSD can much more easily accept breakage between 3.1[.0]
>>> and 3.1.1, than between 3.1.1 and 3.2[.0] as we are still developing 5.0
>>> and can take ABI hits right now.
>> The same applies for SuSE and possible also other distributors,
>
> What's the cut-off date where you (Andreas, David,...) would need to
> have a release of GCC with such a C++ ABI change?

If we get something still in July, it would be perfect.  If it comes
out later, it might be ok but then I would need some release date to
plan for it.  September will be too late.

> There are strong arguments not to make this change for 3.1.1 which is
> due quite soon, but that doesn't prevent us from making another release
> shortly thereafter, for example.

I agree with this reasoning.

Thanks for considering these issues,
Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[David O'Brien]

On Sat, Jul 06, 2002 at 03:18:00PM +0200, Gerald Pfeifer wrote:
> On Sat, 6 Jul 2002, Andreas Jaeger wrote:
> >> I urge you as strongly as I can to back port (#define wrap if needed) the
> >> changes so that GCC 3.1.1 can be built to be 100% C++ ABI compatible with
> >> GCC 3.2.  FreeBSD can much more easily accept breakage between 3.1[.0]
> >> and 3.1.1, than between 3.1.1 and 3.2[.0] as we are still developing 5.0
> >> and can take ABI hits right now.
> > The same applies for SuSE and possible also other distributors,
> 
> What's the cut-off date where you (Andreas, David,...) would need to
> have a release of GCC with such a C++ ABI change?

FreeBSD would need a release with updated C++ ABI by Sept 1, 2002 at the
very latest.

That also assumes that there aren't major regressions in said release.
Example of things that we couldn't have happen with a Sept 1st compiler
are things like:

* the "#pragma weak" bug that caused stock XFree86 4.2.0 to not compile
* the reload bug that could only be avoided by compiling XFree86 with -O0
* that requested alignment isn't obeyed and thus boot blocks can't be
  made small enough
* that with every GCC upgrade we have to tweak our in-line asm statements
* anything that would cause 20% of our 8000 3rd-party packages (The Ports
  Collection) to no longer build.

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[David Edelsohn]

	I have raised this concern to the GCC Steering Committee as well.
It is unclear how much flexibility is available this close to the GCC
3.1.1 announced release date.  Also, the U.S. Independence Day holiday
weekend may delay responses from both U.S.-based GCC SC members and
U.S.-based GCC developers.

	Hopefully the feedback and suggestions from this discussion can
help the GCC SC reach a consensus.

David

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Joseph S. Myers]

On Thu, 4 Jul 2002, Andreas Jaeger wrote:

> What will this mean for distributions and for production usage of GCC
> 3.1?  I fear this means that folks cannot easily upgrade from GCC 3.1
> to GCC 3.2 since C++ is incompatible and all C++ libraries that are
> needed for development need to be relinked.

Where does libstdc++ fit into this?  Is libstdc++ yet ready to be binary
compatible between successive major releases?  If not, how useful is
binary compatibility of the underlying C++ ABI?

-- 
Joseph S. Myers
jsm28@cam.ac.uk

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Gabriel Dos Reis]

"Joseph S. Myers" <jsm28@cam.ac.uk> writes:

| On Thu, 4 Jul 2002, Andreas Jaeger wrote:
| 
| > What will this mean for distributions and for production usage of GCC
| > 3.1?  I fear this means that folks cannot easily upgrade from GCC 3.1
| > to GCC 3.2 since C++ is incompatible and all C++ libraries that are
| > needed for development need to be relinked.
| 
| Where does libstdc++ fit into this?

The library is not covered by the ABI requirement; but we try hard to
retain ABI compatibility.  

|  Is libstdc++ yet ready to be binary
| compatible between successive major releases?

No, we're currently far from that -- but we're striving for that goal.

|  If not, how useful is
| binary compatibility of the underlying C++ ABI?

People have been using third-party libary in place of libstdc++-v3.
Also, most of codes in libstc++-v3 are in headers (template
definitions) so the issue is less sensitive than with the compiler.

-- Gaby

Re: C++ binary compatibility between GCC 3.1 and GCC 3.2?

[Andreas Jaeger]

Gabriel Dos Reis <gdr@codesourcery.com> writes:

> "Joseph S. Myers" <jsm28@cam.ac.uk> writes:
>
> | On Thu, 4 Jul 2002, Andreas Jaeger wrote:
> | 
> | > What will this mean for distributions and for production usage of GCC
> | > 3.1?  I fear this means that folks cannot easily upgrade from GCC 3.1
> | > to GCC 3.2 since C++ is incompatible and all C++ libraries that are
> | > needed for development need to be relinked.
> | 
> | Where does libstdc++ fit into this?
>
> The library is not covered by the ABI requirement; but we try hard to
> retain ABI compatibility.  

With symbol versioning (that is implemented in libstdc++) it shouldn't
be a problem to retain ABI compatibility as long as the C++ ABI is
stable.

Andreas
-- 
 Andreas Jaeger
  SuSE Labs aj@suse.de
   private aj@arthur.inka.de
    http://www.suse.de/~aj