llvm dev - Sep 2016 - [cfe-dev] Revisiting our informal policy to support two versions of MSVC

On Thu, Sep 1, 2016 at 1:30 PM, Aaron Ballman <aaron at aaronballman.com>
wrote:
> On Thu, Sep 1, 2016 at 1:23 PM, Nico Weber via cfe-dev
> <cfe-dev at lists.llvm.org> wrote:
> > As mentioned upthread, we're still on update 2 for various
reasons.
>
> Do you mind elaborating on those reasons?

Off the top of my head, clang-cl couldn't handle the code generated by the
midl compiler in that version until fairly recently, and we've been seeing
link.exe /INCREMENTAL failing intermittently (no reliable repro case
though).

> I think we should require
> the latest updates to MSVC due to the number of issues the updates fix
> (esp regarding the newer language features that people keep using so
> frequently), but I've also not heard a concrete use case as to why we
> shouldn't.
>
Do you mean "require latest updates" in general, or just in this case?
Updating immediately every time a new MSVS release comes out would
definitely be tricky for us.

>
> ~Aaron
>
> >
> > On Thu, Sep 1, 2016 at 1:07 PM, Robinson, Paul <paul.robinson at
sony.com>
> > wrote:
> >>
> >> Hi Reid, first off thanks *very* much for all your help fixing
> >> 2013-related problems.  We really appreciate it.
> >>
> >>
> >>
> >> Let me propose a target date of September 15 for advancing the
minimum
> MS
> >> compiler to VS2015 Update 3.  Certainly my team should be ready by
> then. If
> >> anybody else needs a later date, in particular people who own
Windows
> bots
> >> still using VS2013, please speak up.
> >>
> >> --paulr
> >>
> >>
> >>
> >> From: Reid Kleckner [mailto:rnk at google.com]
> >> Sent: Wednesday, August 31, 2016 4:07 PM
> >> To: Robinson, Paul
> >> Cc: James Molloy; Nico Weber; llvm-dev; cfe-dev at lists.llvm.org
> >> Subject: Re: [llvm-dev] [cfe-dev] Revisiting our informal policy
to
> >> support two versions of MSVC
> >>
> >>
> >>
> >> I'd like to revisit this. As a person who spends a fair amount
of time
> >> monitoring our VS 2013 buildbots, I would say that I am ready to
throw
> in
> >> the towel on MSVC 2013. Since this discussion, I have committed
five (!)
> >> workarounds for MSVC 2013:
> >>
> >>
> >>
> >> # in llvm
> >>
> >> $ git log --author=rnk --grep=2013  --after='Aug 4 2016'
--oneline
> >>
> >> 21a8ade Fix the MSVC 2013 build by using Elf_Word instead of
making a
> >> local typedef
> >>
> >> 27e101d Revert "Add an optional parameter with a list of
undefs to
> >> extendToIndices"
> >>
> >> e8beddd Make vec_fabs.ll pass with MSVC 2013
> >>
> >> ca77873 [AMDGPU] Give enum an explicit 64-bit type to fix MSVC
2013
> >> failures
> >>
> >>
> >>
> >> # in clang
> >>
> >> $ git log --author=rnk --grep=2013  --after='Aug 4 2016'
--oneline
> >>
> >> 18235a5 Try to work around an MSVC 2013 bug around defaulted
default
> ctors
> >>
> >>
> >>
> >> I'm pretty sure I'm missing instances where I helped
others commit
> >> workarounds as well. So, I'd really like to drop 2013,
probably sometime
> >> next month.
> >>
> >>
> >>
> >> That said, I'd also like to echo Paul's sentiment that
it'd help if
> people
> >> were less adventurous in their uses of C++11. New language
features may
> look
> >> nice, but ultimately you may end up wasting my time and yours when
I
> come
> >> and revert your change.
> >>
> >>
> >>
> >> On Thu, Aug 4, 2016 at 7:52 AM, Robinson, Paul via llvm-dev
> >> <llvm-dev at lists.llvm.org> wrote:
> >>
> >> I've heard from another group within Sony that they had
"a number of
> >> problems" with VS2015 update 2, and strongly recommend going
straight to
> >> update 3.  My immediate team has initiated a request but it
hasn't gone
> >> through yet.
> >>
> >> --paulr
> >>
> >>
> >>
> >> From: James Molloy [mailto:james at jamesmolloy.co.uk]
> >> Sent: Wednesday, August 03, 2016 1:54 AM
> >> To: Nico Weber; Robinson, Paul
> >> Cc: llvm-dev; cfe-dev at lists.llvm.org
> >> Subject: Re: [cfe-dev] [llvm-dev] Revisiting our informal policy
to
> >> support two versions of MSVC
> >>
> >>
> >>
> >> Hi,
> >>
> >>
> >>
> >> This sounds like a decent idea to me. However we use 2013 for all
our
> >> windows builds at the moment and it will take around 2 weeks to
upgrade
> the
> >> installations on our cluster. We're pushing this hard to get
it done
> soon so
> >> we don't get caught short, but a grace period would be much
appreciated.
> >>
> >>
> >>
> >> Cheers,
> >>
> >>
> >>
> >> James
> >>
> >>
> >>
> >> On Tue, 2 Aug 2016 at 21:24 Nico Weber via cfe-dev
> >> <cfe-dev at lists.llvm.org> wrote:
> >>
> >> On Tue, Aug 2, 2016 at 3:49 PM, Robinson, Paul via cfe-dev
> >> <cfe-dev at lists.llvm.org> wrote:
> >>
> >> For my project, timing is everything.  We (and I could easily
imagine,
> >>
> >> for many downstream projects) lead time is important.
> >>
> >>
> >>
> >> In Chromium land, we've so far been able to use the same
compiler we use
> >> to build Chrome to build clang. Currently that's MSVS2015
update 2, and
> it
> >> took quite a while to update from 2013 to 2015 due bugs in 2015
and
> whatnot.
> >> So I agree that it's useful to support older MSVS versions for
some
> time.
> >> For this reason, requiring update 3 would be inconvenient for us,
but
> 2015u2
> >> would be no problem by now. It would've been a problem if 2015
had been
> >> required shortly after it was released.
> >>
> >>
> >>
> >> Nico
> >>
> >> _______________________________________________
> >> cfe-dev mailing list
> >> cfe-dev at lists.llvm.org
> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> >>
> >>
> >> _______________________________________________
> >> LLVM Developers mailing list
> >> llvm-dev at lists.llvm.org
> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >>
> >>
> >
> >
> >
> > _______________________________________________
> > cfe-dev mailing list
> > cfe-dev at lists.llvm.org
> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> >
>
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On Thu, Sep 1, 2016 at 2:08 PM, Nico Weber <thakis at chromium.org>
wrote:
> On Thu, Sep 1, 2016 at 1:30 PM, Aaron Ballman <aaron at
aaronballman.com>
> wrote:
>>
>> On Thu, Sep 1, 2016 at 1:23 PM, Nico Weber via cfe-dev
>> <cfe-dev at lists.llvm.org> wrote:
>> > As mentioned upthread, we're still on update 2 for various
reasons.
>>
>> Do you mind elaborating on those reasons?
>
>
> Off the top of my head, clang-cl couldn't handle the code generated by
the
> midl compiler in that version until fairly recently, and we've been
seeing
> link.exe /INCREMENTAL failing intermittently (no reliable repro case
> though).
Thank you for the extra information.
>
>>
>> I think we should require
>> the latest updates to MSVC due to the number of issues the updates fix
>> (esp regarding the newer language features that people keep using so
>> frequently), but I've also not heard a concrete use case as to why
we
>> shouldn't.
>
>
> Do you mean "require latest updates" in general, or just in this
case?
> Updating immediately every time a new MSVS release comes out would
> definitely be tricky for us.
I mean in general, but "immediate" wasn't what I had in mind. More
like "within some reasonable time frame", for whatever definition of
reasonable works for people. Given how often Microsoft fixes critical
language bugs with newer features during an Update release, I'm hoping
we can avoid sticking to older Updates if we are able to do so.

~Aaron
>
>>
>>
>> ~Aaron
>>
>> >
>> > On Thu, Sep 1, 2016 at 1:07 PM, Robinson, Paul <paul.robinson
at sony.com>
>> > wrote:
>> >>
>> >> Hi Reid, first off thanks *very* much for all your help fixing
>> >> 2013-related problems.  We really appreciate it.
>> >>
>> >>
>> >>
>> >> Let me propose a target date of September 15 for advancing the
minimum
>> >> MS
>> >> compiler to VS2015 Update 3.  Certainly my team should be
ready by
>> >> then. If
>> >> anybody else needs a later date, in particular people who own
Windows
>> >> bots
>> >> still using VS2013, please speak up.
>> >>
>> >> --paulr
>> >>
>> >>
>> >>
>> >> From: Reid Kleckner [mailto:rnk at google.com]
>> >> Sent: Wednesday, August 31, 2016 4:07 PM
>> >> To: Robinson, Paul
>> >> Cc: James Molloy; Nico Weber; llvm-dev; cfe-dev at
lists.llvm.org
>> >> Subject: Re: [llvm-dev] [cfe-dev] Revisiting our informal
policy to
>> >> support two versions of MSVC
>> >>
>> >>
>> >>
>> >> I'd like to revisit this. As a person who spends a fair
amount of time
>> >> monitoring our VS 2013 buildbots, I would say that I am ready
to throw
>> >> in
>> >> the towel on MSVC 2013. Since this discussion, I have
committed five
>> >> (!)
>> >> workarounds for MSVC 2013:
>> >>
>> >>
>> >>
>> >> # in llvm
>> >>
>> >> $ git log --author=rnk --grep=2013  --after='Aug 4
2016' --oneline
>> >>
>> >> 21a8ade Fix the MSVC 2013 build by using Elf_Word instead of
making a
>> >> local typedef
>> >>
>> >> 27e101d Revert "Add an optional parameter with a list of
undefs to
>> >> extendToIndices"
>> >>
>> >> e8beddd Make vec_fabs.ll pass with MSVC 2013
>> >>
>> >> ca77873 [AMDGPU] Give enum an explicit 64-bit type to fix MSVC
2013
>> >> failures
>> >>
>> >>
>> >>
>> >> # in clang
>> >>
>> >> $ git log --author=rnk --grep=2013  --after='Aug 4
2016' --oneline
>> >>
>> >> 18235a5 Try to work around an MSVC 2013 bug around defaulted
default
>> >> ctors
>> >>
>> >>
>> >>
>> >> I'm pretty sure I'm missing instances where I helped
others commit
>> >> workarounds as well. So, I'd really like to drop 2013,
probably
>> >> sometime
>> >> next month.
>> >>
>> >>
>> >>
>> >> That said, I'd also like to echo Paul's sentiment that
it'd help if
>> >> people
>> >> were less adventurous in their uses of C++11. New language
features may
>> >> look
>> >> nice, but ultimately you may end up wasting my time and yours
when I
>> >> come
>> >> and revert your change.
>> >>
>> >>
>> >>
>> >> On Thu, Aug 4, 2016 at 7:52 AM, Robinson, Paul via llvm-dev
>> >> <llvm-dev at lists.llvm.org> wrote:
>> >>
>> >> I've heard from another group within Sony that they had
"a number of
>> >> problems" with VS2015 update 2, and strongly recommend
going straight
>> >> to
>> >> update 3.  My immediate team has initiated a request but it
hasn't gone
>> >> through yet.
>> >>
>> >> --paulr
>> >>
>> >>
>> >>
>> >> From: James Molloy [mailto:james at jamesmolloy.co.uk]
>> >> Sent: Wednesday, August 03, 2016 1:54 AM
>> >> To: Nico Weber; Robinson, Paul
>> >> Cc: llvm-dev; cfe-dev at lists.llvm.org
>> >> Subject: Re: [cfe-dev] [llvm-dev] Revisiting our informal
policy to
>> >> support two versions of MSVC
>> >>
>> >>
>> >>
>> >> Hi,
>> >>
>> >>
>> >>
>> >> This sounds like a decent idea to me. However we use 2013 for
all our
>> >> windows builds at the moment and it will take around 2 weeks
to upgrade
>> >> the
>> >> installations on our cluster. We're pushing this hard to
get it done
>> >> soon so
>> >> we don't get caught short, but a grace period would be
much
>> >> appreciated.
>> >>
>> >>
>> >>
>> >> Cheers,
>> >>
>> >>
>> >>
>> >> James
>> >>
>> >>
>> >>
>> >> On Tue, 2 Aug 2016 at 21:24 Nico Weber via cfe-dev
>> >> <cfe-dev at lists.llvm.org> wrote:
>> >>
>> >> On Tue, Aug 2, 2016 at 3:49 PM, Robinson, Paul via cfe-dev
>> >> <cfe-dev at lists.llvm.org> wrote:
>> >>
>> >> For my project, timing is everything.  We (and I could easily
imagine,
>> >>
>> >> for many downstream projects) lead time is important.
>> >>
>> >>
>> >>
>> >> In Chromium land, we've so far been able to use the same
compiler we
>> >> use
>> >> to build Chrome to build clang. Currently that's MSVS2015
update 2, and
>> >> it
>> >> took quite a while to update from 2013 to 2015 due bugs in
2015 and
>> >> whatnot.
>> >> So I agree that it's useful to support older MSVS versions
for some
>> >> time.
>> >> For this reason, requiring update 3 would be inconvenient for
us, but
>> >> 2015u2
>> >> would be no problem by now. It would've been a problem if
2015 had been
>> >> required shortly after it was released.
>> >>
>> >>
>> >>
>> >> Nico
>> >>
>> >> _______________________________________________
>> >> cfe-dev mailing list
>> >> cfe-dev at lists.llvm.org
>> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>> >>
>> >>
>> >> _______________________________________________
>> >> LLVM Developers mailing list
>> >> llvm-dev at lists.llvm.org
>> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>> >>
>> >>
>> >
>> >
>> >
>> > _______________________________________________
>> > cfe-dev mailing list
>> > cfe-dev at lists.llvm.org
>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>> >
>
>

I frequently see mention of how upgrading is problematic, is there anyone
here for whom upgrading msvc versions is problematic? It seems like we keep
talking in hypotheticals, but I'd like to hear from someone for whom it is
*actually* a problem, and why.

Vs community is permissive enough now that licensing isn't an issue. And
every time this comes up it seems like we're saying "well it could be
hard
for people..." but nobody ever says it actually is hard for them
specifically


On Thu, Sep 1, 2016 at 11:16 AM Aaron Ballman via cfe-dev <
cfe-dev at lists.llvm.org> wrote:
> On Thu, Sep 1, 2016 at 2:08 PM, Nico Weber <thakis at chromium.org>
wrote:
> > On Thu, Sep 1, 2016 at 1:30 PM, Aaron Ballman <aaron at
aaronballman.com>
> > wrote:
> >>
> >> On Thu, Sep 1, 2016 at 1:23 PM, Nico Weber via cfe-dev
> >> <cfe-dev at lists.llvm.org> wrote:
> >> > As mentioned upthread, we're still on update 2 for
various reasons.
> >>
> >> Do you mind elaborating on those reasons?
> >
> >
> > Off the top of my head, clang-cl couldn't handle the code
generated by
> the
> > midl compiler in that version until fairly recently, and we've
been
> seeing
> > link.exe /INCREMENTAL failing intermittently (no reliable repro case
> > though).
>
> Thank you for the extra information.
>
> >
> >>
> >> I think we should require
> >> the latest updates to MSVC due to the number of issues the updates
fix
> >> (esp regarding the newer language features that people keep using
so
> >> frequently), but I've also not heard a concrete use case as to
why we
> >> shouldn't.
> >
> >
> > Do you mean "require latest updates" in general, or just in
this case?
> > Updating immediately every time a new MSVS release comes out would
> > definitely be tricky for us.
>
> I mean in general, but "immediate" wasn't what I had in mind.
More
> like "within some reasonable time frame", for whatever definition
of
> reasonable works for people. Given how often Microsoft fixes critical
> language bugs with newer features during an Update release, I'm hoping
> we can avoid sticking to older Updates if we are able to do so.
>
> ~Aaron
>
> >
> >>
> >>
> >> ~Aaron
> >>
> >> >
> >> > On Thu, Sep 1, 2016 at 1:07 PM, Robinson, Paul <
> paul.robinson at sony.com>
> >> > wrote:
> >> >>
> >> >> Hi Reid, first off thanks *very* much for all your help
fixing
> >> >> 2013-related problems.  We really appreciate it.
> >> >>
> >> >>
> >> >>
> >> >> Let me propose a target date of September 15 for
advancing the
> minimum
> >> >> MS
> >> >> compiler to VS2015 Update 3.  Certainly my team should be
ready by
> >> >> then. If
> >> >> anybody else needs a later date, in particular people who
own Windows
> >> >> bots
> >> >> still using VS2013, please speak up.
> >> >>
> >> >> --paulr
> >> >>
> >> >>
> >> >>
> >> >> From: Reid Kleckner [mailto:rnk at google.com]
> >> >> Sent: Wednesday, August 31, 2016 4:07 PM
> >> >> To: Robinson, Paul
> >> >> Cc: James Molloy; Nico Weber; llvm-dev; cfe-dev at
lists.llvm.org
> >> >> Subject: Re: [llvm-dev] [cfe-dev] Revisiting our informal
policy to
> >> >> support two versions of MSVC
> >> >>
> >> >>
> >> >>
> >> >> I'd like to revisit this. As a person who spends a
fair amount of
> time
> >> >> monitoring our VS 2013 buildbots, I would say that I am
ready to
> throw
> >> >> in
> >> >> the towel on MSVC 2013. Since this discussion, I have
committed five
> >> >> (!)
> >> >> workarounds for MSVC 2013:
> >> >>
> >> >>
> >> >>
> >> >> # in llvm
> >> >>
> >> >> $ git log --author=rnk --grep=2013  --after='Aug 4
2016' --oneline
> >> >>
> >> >> 21a8ade Fix the MSVC 2013 build by using Elf_Word instead
of making a
> >> >> local typedef
> >> >>
> >> >> 27e101d Revert "Add an optional parameter with a
list of undefs to
> >> >> extendToIndices"
> >> >>
> >> >> e8beddd Make vec_fabs.ll pass with MSVC 2013
> >> >>
> >> >> ca77873 [AMDGPU] Give enum an explicit 64-bit type to fix
MSVC 2013
> >> >> failures
> >> >>
> >> >>
> >> >>
> >> >> # in clang
> >> >>
> >> >> $ git log --author=rnk --grep=2013  --after='Aug 4
2016' --oneline
> >> >>
> >> >> 18235a5 Try to work around an MSVC 2013 bug around
defaulted default
> >> >> ctors
> >> >>
> >> >>
> >> >>
> >> >> I'm pretty sure I'm missing instances where I
helped others commit
> >> >> workarounds as well. So, I'd really like to drop
2013, probably
> >> >> sometime
> >> >> next month.
> >> >>
> >> >>
> >> >>
> >> >> That said, I'd also like to echo Paul's sentiment
that it'd help if
> >> >> people
> >> >> were less adventurous in their uses of C++11. New
language features
> may
> >> >> look
> >> >> nice, but ultimately you may end up wasting my time and
yours when I
> >> >> come
> >> >> and revert your change.
> >> >>
> >> >>
> >> >>
> >> >> On Thu, Aug 4, 2016 at 7:52 AM, Robinson, Paul via
llvm-dev
> >> >> <llvm-dev at lists.llvm.org> wrote:
> >> >>
> >> >> I've heard from another group within Sony that they
had "a number of
> >> >> problems" with VS2015 update 2, and strongly
recommend going straight
> >> >> to
> >> >> update 3.  My immediate team has initiated a request but
it hasn't
> gone
> >> >> through yet.
> >> >>
> >> >> --paulr
> >> >>
> >> >>
> >> >>
> >> >> From: James Molloy [mailto:james at jamesmolloy.co.uk]
> >> >> Sent: Wednesday, August 03, 2016 1:54 AM
> >> >> To: Nico Weber; Robinson, Paul
> >> >> Cc: llvm-dev; cfe-dev at lists.llvm.org
> >> >> Subject: Re: [cfe-dev] [llvm-dev] Revisiting our informal
policy to
> >> >> support two versions of MSVC
> >> >>
> >> >>
> >> >>
> >> >> Hi,
> >> >>
> >> >>
> >> >>
> >> >> This sounds like a decent idea to me. However we use 2013
for all our
> >> >> windows builds at the moment and it will take around 2
weeks to
> upgrade
> >> >> the
> >> >> installations on our cluster. We're pushing this hard
to get it done
> >> >> soon so
> >> >> we don't get caught short, but a grace period would
be much
> >> >> appreciated.
> >> >>
> >> >>
> >> >>
> >> >> Cheers,
> >> >>
> >> >>
> >> >>
> >> >> James
> >> >>
> >> >>
> >> >>
> >> >> On Tue, 2 Aug 2016 at 21:24 Nico Weber via cfe-dev
> >> >> <cfe-dev at lists.llvm.org> wrote:
> >> >>
> >> >> On Tue, Aug 2, 2016 at 3:49 PM, Robinson, Paul via
cfe-dev
> >> >> <cfe-dev at lists.llvm.org> wrote:
> >> >>
> >> >> For my project, timing is everything.  We (and I could
easily
> imagine,
> >> >>
> >> >> for many downstream projects) lead time is important.
> >> >>
> >> >>
> >> >>
> >> >> In Chromium land, we've so far been able to use the
same compiler we
> >> >> use
> >> >> to build Chrome to build clang. Currently that's
MSVS2015 update 2,
> and
> >> >> it
> >> >> took quite a while to update from 2013 to 2015 due bugs
in 2015 and
> >> >> whatnot.
> >> >> So I agree that it's useful to support older MSVS
versions for some
> >> >> time.
> >> >> For this reason, requiring update 3 would be inconvenient
for us, but
> >> >> 2015u2
> >> >> would be no problem by now. It would've been a
problem if 2015 had
> been
> >> >> required shortly after it was released.
> >> >>
> >> >>
> >> >>
> >> >> Nico
> >> >>
> >> >> _______________________________________________
> >> >> cfe-dev mailing list
> >> >> cfe-dev at lists.llvm.org
> >> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> >> >>
> >> >>
> >> >> _______________________________________________
> >> >> LLVM Developers mailing list
> >> >> llvm-dev at lists.llvm.org
> >> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >> >>
> >> >>
> >> >
> >> >
> >> >
> >> > _______________________________________________
> >> > cfe-dev mailing list
> >> > cfe-dev at lists.llvm.org
> >> > http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
> >> >
> >
> >
> _______________________________________________
> cfe-dev mailing list
> cfe-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev
>
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