Consider me on board with the highest version we can come to an agreement on :) On Thu, May 10, 2018 at 11:50 AM JF Bastien <jfbastien at apple.com> wrote:> > On May 10, 2018, at 11:35 AM, Zachary Turner <zturner at google.com> wrote: > > If it's the only thing we can agree then I'll take it, but I just worry > that 3 years from now we're going to start another 3 year discussion, so > that any actual move to C++17 would end up taking double the time. > > > Such a fatalistic view, let’s trust ourselves to be better next time ;-) > But seriously: we can learn from moving to C++14, and use what we’ve > learned to move to C++17 faster next time. Also consider the code churn > we’ll encounter as we fix incompatibilities with C++11 / C++14, drop > unnecessary code, upgrade various uses, that will happen regardless of > moving to C++17 and will take a little while to occur. There would be more > of that type of churn if we went straight to C++17. > > > Are the issues specific to C++17 additions to the standard library? What > if you allow C++17 language features but not C++17 library features? I'm > guessing this is too simple though and isn't sufficient to avoid the > problems (which I don't know anything about, so you'll have to enlighten > me)? > > > Mostly library so far, yes, but the GCC 6 support for C++17 language isn’t > great either: > > - New auto rules for direct-list-initialization > - static_assert with no message > - typename in a template template parameter > - Nested namespace definition > - Attributes for namespaces and enumerators > - u8 character literals > - Allow constant evaluation for all non-type template arguments > - Fold Expressions > - Unary fold expressions and empty parameter packs > - __has_include in preprocessor conditional > - Differing begin and end types in range-based for\ > > From: https://en.cppreference.com/w/cpp/compiler_support > > The only thing that’s really nice are fold expressions, and I hope they’re > not buggy in GCC 6. > > Otherwise the list is missing a good amount for C++17 language features, > and brings up the discussion of which GCC version is the minimum we > mandate. I’d rather avoid that discussion. Let’s assume GCC 6, if we get 7 > then great, but it doesn’t matter if we stick to C++14. > > > On Thu, May 10, 2018 at 11:28 AM JF Bastien <jfbastien at apple.com> wrote: > >> >> On May 10, 2018, at 11:22 AM, Zachary Turner <zturner at google.com> wrote: >> >> Windows has never been the issue. Honestly, MSVC on Windows is "fully >> C++17 conformant" [1]. >> >> The issue has and always will be GCC. Given that a bump in any version >> of GCC has been (and will remain) difficult for some time, I propose that >> we skip C++14 and move to 17. We don't want to have a multi-year >> disccusion about this again any time soon, and from what I gather, nobody >> has any more reservations about moving to C++17 than they do about moving >> to C++14. They only have reservations about moving to anything at all. So >> if we're gonna move, we should go all the way. >> >> >> WebKit’s move to C++17 hasn’t been super smooth because of GCC / >> libstdc++ issues in both GCC 6 and GCC 7. It’s all fixable, but given >> LLVM's slow move out of C++11 I’d rather get C++14 now rather than a >> painful transition to C++17 that drags on as we discover issues. >> >> >> Just my 2c. >> >> [1] >> https://blogs.msdn.microsoft.com/vcblog/2018/05/07/announcing-msvc-conforms-to-the-c-standard/ >> >> On Thu, May 10, 2018 at 11:18 AM Eric Christopher <echristo at gmail.com> >> wrote: >> >>> Once again, I'm totally down for this and think we should do it. I worry >>> about windows, but ... >>> >>> Zach: How's windows c++14 support looking? >>> >>> -eric >>> >>> On Thu, May 10, 2018 at 10:01 AM JF Bastien via llvm-dev < >>> llvm-dev at lists.llvm.org> wrote: >>> >>>> Hi folks! >>>> >>>> Six more months have come and gone, and maybe we could move LLVM to >>>> C++14 now? >>>> >>>> The issues I picked out from the last discussion: >>>> >>>> 1. Some folks want an official policy about compiler support before >>>> updating the standard version we use. >>>> 2. Worries about which GCC version is available in which distro. >>>> 3. Worries about MSVC. >>>> >>>> >>>> Instead of rehashing the compiler per distro surveys from previous >>>> discussion, and instead of talking bootstrap, let me offer three data >>>> points: >>>> >>>> - WebKit is moving to C++17 >>>> <https://lists.webkit.org/pipermail/webkit-dev/2018-March/029922.html> (from >>>> C++14) right now † >>>> - Chromium started moving to C++14 >>>> <https://groups.google.com/a/chromium.org/d/msg/cxx/ow7hmdDm4yw/eV6KWL2yAQAJ> in >>>> August of last year >>>> - Firefox uses some C++14 >>>> <https://developer.mozilla.org/en-US/docs/Mozilla/Using_CXX_in_Mozilla_code> >>>> >>>> What I get from this data: if your distro bundles a modern web browser, >>>> it already builds some C++14, *somehow*. >>>> >>>> The LLVM community has been talking about this for a while now, and I’m >>>> not aware of a policy coming to light. I don’t think we need a policy given >>>> the above data. So how about we… just kinda... move LLVM to C++14? >>>> >>>> >>>> Thanks! >>>> >>>> JF >>>> >>>> >>>> † the move to C++17 is very painful, but 14 has been working great in >>>> WebKit for quite a long time. >>>> >>>> >>>> > Last time we discussed this, the consensus was "I think we can survive >>>> > another year without generalized constexpr and variable templates". >>>> > >>>> > Well, we did indeed survive. And it's been exactly a year! So >>>> naturally, >>>> > it only makes sense to revive this :) >>>> > >>>> > >>>> > >>>> > There's an active conversation going on in IRC right now, and it >>>> seems like >>>> > there is more desire than there was last year. >>>> > >>>> > What are the main gains from allowing C++14? >>>> > * Variable templates >>>> > * Generalized constexpr >>>> > * Return-type Deduction >>>> > * Generic Lambdas >>>> > * std::make_unique<> (the source of many build bot breakages) >>>> > >>>> > >>>> > What are the main gains from allowing C++17? [1] >>>> > * [[nodiscard]] attribute >>>> > * structured bindings >>>> > * constexpr-if >>>> > * guaranteed copy elision >>>> > * numerous new library types: optional, string_view, variant, byte, >>>> > * numerous new algorithms: parallel algorithms, too many to list >>>> > * Probably some more, but I just tried to hit the biggest ones. >>>> > >>>> > >>>> > First, it seems like if we want to enable C++14 we need GCC >= 5. >>>> > And if we want to enable C++17 we need GCC >= 7. >>>> > >>>> > With that out of the way, here were some of the issues that were >>>> raised >>>> > last time: >>>> > >>>> > Issue: Ubuntu 14.04 LTS is on GCC 4.8.x, and we have to support it >>>> until >>>> > end of life. >>>> > Resolution: LTS is right around the corner, in 6 more months. >>>> > >>>> > Issue: Various other platforms have older GCCs as their system >>>> compiler, >>>> > and it's annoying to upgrade. >>>> > Question: Do any of these not have a port you can install? For >>>> example, >>>> > NetBSD 7 appears to have GCC 5.3 as a port, if DistroWatch is any >>>> > indication. It could be wrong though and I could also be >>>> misinterpreting >>>> > it. >>>> > >>>> > Issue: If we're going to make people bootstrap a compiler, we might >>>> as well >>>> > go all the way to C++17. >>>> > Comment: I'm not opposed. >>>> > >>>> > >>>> > Some questions / comments of my own: >>>> > >>>> > * Where is this policy about Ubuntu and LTS documented? Does this >>>> mean, >>>> > for example, that we will not be able to use C++17 until 2023 (16.04 >>>> LTS >>>> > has only GCC 5.3.1)? That seems a bit unreasonable. And there's no >>>> > guarantee that 18.04 LTS will even have GCC 7 or higher either, so it >>>> could >>>> > be 2025 or 2027. >>>> > >>>> > * We've asked people in the past to build a modern toolchain. For >>>> example, >>>> > we did it with C++11 and Ubuntu 12.04 LTS. Is C++17 compelling >>>> enough to >>>> > justify this again? >>>> > >>>> > * GCC 4.9 probably isn't sufficient to justify an increase for >>>> anyone, as >>>> > it lacks two of the more sought-after features of C++14 (variable >>>> templates >>>> > and generalized constexpr). So IMO we should require a bump to GCC 5 >>>> or >>>> > higher, or not at all. >>>> > >>>> > * Clang 6 supports all of C++20, and it builds with only C++11, so we >>>> > shouldn't have to worry too much about the problem of needing to >>>> "daisy >>>> > chain" compilers to finally get the latest version of LLVM building. >>>> "GCC >>>> > 4.8 -> Clang 6 - > Clang ToT" should hold up through C++1z. >>>> > >>>> > * While we obviously can't be tied to the versioning of every single >>>> distro >>>> > out there, some are "bigger" than others. Which are big enough that >>>> > warrant serious consideration? The ones I found are (and I did my >>>> best to >>>> > aggregate all this, but please correct me if anything is incorrect or >>>> > misrepresented): >>>> > >>>> > OpenBSD - Ships with GCC 4.2.1 anyway. They are already having to >>>> > bootstrap something, so the proposal here does not change anything, >>>> because >>>> > even current LLVM doesn't compile with GCC 4.2.1 >>>> > >>>> > CentOS & RHEL - No version of Distro, including trunk, has GCC >>>>> 4.8.5 >>>> > (are there ports?) >>>> > >>>> > Debian - Minimum version 9 for GCC >= 5 (are there ports for earlier >>>> > releases?) >>>> > >>>> > Fedora - Minimum version 24 for GCC >= 5, minimum version 26 for GCC >>>> >= 7 >>>> > >>>> > Ubuntu - Minimum LTS 16.04 for GCC >= 5 >>>> > >>>> > NetBSD - Version 7 has GCC 4.8.4 by default, but contains port for >>>> 5.3.0 >>>> > >>>> > FreeBSD - Minimum Version 11 for GCC >= 5 >>>> > >>>> > So, thoughts? >>>> > >>>> > >>>> > [1] - Note that we'd need to wait a few more revs for MSVC before >>>> allowing >>>> > C++17, but given that it's becoming easier and easier to bump the >>>> minimum >>>> > MSVC version, I'm discounting this as a factor, as MSVC will not >>>> really be >>>> > the bottleneck in any real sense. >>>> > >>>> > On Tue, Oct 4, 2016 at 2:15 PM Mehdi Amini <mehdi.amini at apple.com> >>>> wrote: >>>> > >>>> >> >>>> >> On Oct 4, 2016, at 2:10 PM, Reid Kleckner <rnk at google.com> wrote: >>>> >> >>>> >> On Tue, Oct 4, 2016 at 11:58 AM, Mehdi Amini <mehdi.amini at >>>> apple.com> >>>> >> wrote: >>>> >> >>>> >>> >>>> >>> On Oct 4, 2016, at 8:40 AM, Reid Kleckner via llvm-dev < >>>> >>> llvm-dev at lists.llvm.org> wrote: >>>> >>> >>>> >>> On Tue, Oct 4, 2016 at 8:29 AM, Zachary Turner <zturner at >>>> google.com> >>>> >>> wrote: >>>> >>>> >>>> >>>> I ask because many of these LTS distros are notoriously slow at >>>> updating >>>> >>>> their packages. While some people may think C++14 doesn't provide >>>> enough >>>> >>>> bang for the buck to justify bumping to GCC 4.9, C++17 definitely >>>> does. But >>>> >>>> at that point we're going to be talking about GCC 6.1 or 6.2, >>>> which is >>>> >>>> going to be significantly harder unless we want to wait 5-7 years, >>>> and I >>>> >>>> suspect people won't. >>>> >>>> >>>> >>> >>>> >>> If by "notoriously slow" you mean they don't bump their toolchain >>>> >>> versions at all, then yeah. We just wait until the LTS release is at >>>> >>> end-of-life before dropping it. >>>> >>> >>>> >>> >>>> >>> That’s the first time I read about this policy: we support every >>>> linux >>>> >>> LTS distribution till their end-of-life? Only Ubuntu? Do you have a >>>> pointer >>>> >>> where it is documented / discussed? >>>> >>> (Note that Ubuntu LTS is 5 years AFAIK.) >>>> >>> >>>> >> >>>> >> Sorry, I didn't mean to refer to the LTS support lifetime. I just >>>> meant we >>>> >> support the last LTS until we can reasonably expect users to have >>>> upgraded >>>> >> to the new one. If there's an LTS release every two years, then we >>>> want to >>>> >> keep supporting them for at least three years to give people a year >>>> to >>>> >> upgrade. >>>> >> >>>> >> >>>> >> OK, got it. >>>> >> >>>> >> Thanks for clarifying! >>>> >> >>>> >> Mehdi >>>> >> >>>> >> >>>> _______________________________________________ >>>> LLVM Developers mailing list >>>> llvm-dev at lists.llvm.org >>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >>>> >>>-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20180510/39c3826b/attachment-0001.html>
Well… Ubuntu 16.04 came with gcc 5, and deploying Visual Studio 2015 should be a
done deal in Windows shops, which suggests moving to C++14 should be no problem.
It's nice to see this week's version of MSVC supports C++17 but
deploying through corporate IT can take a while. ("This week's
version" because the blog post is dated Monday.)
--paulr
From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Zachary
Turner via llvm-dev
Sent: Thursday, May 10, 2018 3:00 PM
To: JF Bastien
Cc: via llvm-dev
Subject: Re: [llvm-dev] Using C++14 code in LLVM
Consider me on board with the highest version we can come to an agreement on :)
On Thu, May 10, 2018 at 11:50 AM JF Bastien <jfbastien at
apple.com<mailto:jfbastien at apple.com>> wrote:
On May 10, 2018, at 11:35 AM, Zachary Turner <zturner at
google.com<mailto:zturner at google.com>> wrote:
If it's the only thing we can agree then I'll take it, but I just worry
that 3 years from now we're going to start another 3 year discussion, so
that any actual move to C++17 would end up taking double the time.
Such a fatalistic view, let’s trust ourselves to be better next time ;-)
But seriously: we can learn from moving to C++14, and use what we’ve learned to
move to C++17 faster next time. Also consider the code churn we’ll encounter as
we fix incompatibilities with C++11 / C++14, drop unnecessary code, upgrade
various uses, that will happen regardless of moving to C++17 and will take a
little while to occur. There would be more of that type of churn if we went
straight to C++17.
Are the issues specific to C++17 additions to the standard library? What if you
allow C++17 language features but not C++17 library features? I'm guessing
this is too simple though and isn't sufficient to avoid the problems (which
I don't know anything about, so you'll have to enlighten me)?
Mostly library so far, yes, but the GCC 6 support for C++17 language isn’t great
either:
- New auto rules for direct-list-initialization
- static_assert with no message
- typename in a template template parameter
- Nested namespace definition
- Attributes for namespaces and enumerators
- u8 character literals
- Allow constant evaluation for all non-type template arguments
- Fold Expressions
- Unary fold expressions and empty parameter packs
- __has_include in preprocessor conditional
- Differing begin and end types in range-based for\
From: https://en.cppreference.com/w/cpp/compiler_support
The only thing that’s really nice are fold expressions, and I hope they’re not
buggy in GCC 6.
Otherwise the list is missing a good amount for C++17 language features, and
brings up the discussion of which GCC version is the minimum we mandate. I’d
rather avoid that discussion. Let’s assume GCC 6, if we get 7 then great, but it
doesn’t matter if we stick to C++14.
On Thu, May 10, 2018 at 11:28 AM JF Bastien <jfbastien at
apple.com<mailto:jfbastien at apple.com>> wrote:
On May 10, 2018, at 11:22 AM, Zachary Turner <zturner at
google.com<mailto:zturner at google.com>> wrote:
Windows has never been the issue. Honestly, MSVC on Windows is "fully
C++17 conformant" [1].
The issue has and always will be GCC. Given that a bump in any version of GCC
has been (and will remain) difficult for some time, I propose that we skip C++14
and move to 17. We don't want to have a multi-year disccusion about this
again any time soon, and from what I gather, nobody has any more reservations
about moving to C++17 than they do about moving to C++14. They only have
reservations about moving to anything at all. So if we're gonna move, we
should go all the way.
WebKit’s move to C++17 hasn’t been super smooth because of GCC / libstdc++
issues in both GCC 6 and GCC 7. It’s all fixable, but given LLVM's slow move
out of C++11 I’d rather get C++14 now rather than a painful transition to C++17
that drags on as we discover issues.
Just my 2c.
[1]
https://blogs.msdn.microsoft.com/vcblog/2018/05/07/announcing-msvc-conforms-to-the-c-standard/
On Thu, May 10, 2018 at 11:18 AM Eric Christopher <echristo at
gmail.com<mailto:echristo at gmail.com>> wrote:
Once again, I'm totally down for this and think we should do it. I worry
about windows, but ...
Zach: How's windows c++14 support looking?
-eric
On Thu, May 10, 2018 at 10:01 AM JF Bastien via llvm-dev <llvm-dev at
lists.llvm.org<mailto:llvm-dev at lists.llvm.org>> wrote:
Hi folks!
Six more months have come and gone, and maybe we could move LLVM to C++14 now?
The issues I picked out from the last discussion:
1. Some folks want an official policy about compiler support before updating
the standard version we use.
2. Worries about which GCC version is available in which distro.
3. Worries about MSVC.
Instead of rehashing the compiler per distro surveys from previous discussion,
and instead of talking bootstrap, let me offer three data points:
* WebKit is moving to
C++17<https://lists.webkit.org/pipermail/webkit-dev/2018-March/029922.html>
(from C++14) right now †
* Chromium started moving to
C++14<https://groups.google.com/a/chromium.org/d/msg/cxx/ow7hmdDm4yw/eV6KWL2yAQAJ>
in August of last year
* Firefox uses some
C++14<https://developer.mozilla.org/en-US/docs/Mozilla/Using_CXX_in_Mozilla_code>
What I get from this data: if your distro bundles a modern web browser, it
already builds some C++14, somehow.
The LLVM community has been talking about this for a while now, and I’m not
aware of a policy coming to light. I don’t think we need a policy given the
above data. So how about we… just kinda... move LLVM to C++14?
Thanks!
JF
† the move to C++17 is very painful, but 14 has been working great in WebKit for
quite a long time.
> Last time we discussed this, the consensus was "I think we can survive
> another year without generalized constexpr and variable templates".
>
> Well, we did indeed survive. And it's been exactly a year! So
naturally,
> it only makes sense to revive this :)
>
>
>
> There's an active conversation going on in IRC right now, and it seems
like
> there is more desire than there was last year.
>
> What are the main gains from allowing C++14?
> * Variable templates
> * Generalized constexpr
> * Return-type Deduction
> * Generic Lambdas
> * std::make_unique<> (the source of many build bot breakages)
>
>
> What are the main gains from allowing C++17? [1]
> * [[nodiscard]] attribute
> * structured bindings
> * constexpr-if
> * guaranteed copy elision
> * numerous new library types: optional, string_view, variant, byte,
> * numerous new algorithms: parallel algorithms, too many to list
> * Probably some more, but I just tried to hit the biggest ones.
>
>
> First, it seems like if we want to enable C++14 we need GCC >= 5.
> And if we want to enable C++17 we need GCC >= 7.
>
> With that out of the way, here were some of the issues that were raised
> last time:
>
> Issue: Ubuntu 14.04 LTS is on GCC 4.8.x, and we have to support it until
> end of life.
> Resolution: LTS is right around the corner, in 6 more months.
>
> Issue: Various other platforms have older GCCs as their system compiler,
> and it's annoying to upgrade.
> Question: Do any of these not have a port you can install? For example,
> NetBSD 7 appears to have GCC 5.3 as a port, if DistroWatch is any
> indication. It could be wrong though and I could also be misinterpreting
> it.
>
> Issue: If we're going to make people bootstrap a compiler, we might as
well
> go all the way to C++17.
> Comment: I'm not opposed.
>
>
> Some questions / comments of my own:
>
> * Where is this policy about Ubuntu and LTS documented? Does this mean,
> for example, that we will not be able to use C++17 until 2023 (16.04 LTS
> has only GCC 5.3.1)? That seems a bit unreasonable. And there's no
> guarantee that 18.04 LTS will even have GCC 7 or higher either, so it could
> be 2025 or 2027.
>
> * We've asked people in the past to build a modern toolchain. For
example,
> we did it with C++11 and Ubuntu 12.04 LTS. Is C++17 compelling enough to
> justify this again?
>
> * GCC 4.9 probably isn't sufficient to justify an increase for anyone,
as
> it lacks two of the more sought-after features of C++14 (variable templates
> and generalized constexpr). So IMO we should require a bump to GCC 5 or
> higher, or not at all.
>
> * Clang 6 supports all of C++20, and it builds with only C++11, so we
> shouldn't have to worry too much about the problem of needing to
"daisy
> chain" compilers to finally get the latest version of LLVM building.
"GCC
> 4.8 -> Clang 6 - > Clang ToT" should hold up through C++1z.
>
> * While we obviously can't be tied to the versioning of every single
distro
> out there, some are "bigger" than others. Which are big enough
that
> warrant serious consideration? The ones I found are (and I did my best to
> aggregate all this, but please correct me if anything is incorrect or
> misrepresented):
>
> OpenBSD - Ships with GCC 4.2.1 anyway. They are already having to
> bootstrap something, so the proposal here does not change anything, because
> even current LLVM doesn't compile with GCC 4.2.1
>
> CentOS & RHEL - No version of Distro, including trunk, has GCC >=
4.8.5
> (are there ports?)
>
> Debian - Minimum version 9 for GCC >= 5 (are there ports for earlier
> releases?)
>
> Fedora - Minimum version 24 for GCC >= 5, minimum version 26 for GCC
>= 7
>
> Ubuntu - Minimum LTS 16.04 for GCC >= 5
>
> NetBSD - Version 7 has GCC 4.8.4 by default, but contains port for 5.3.0
>
> FreeBSD - Minimum Version 11 for GCC >= 5
>
> So, thoughts?
>
>
> [1] - Note that we'd need to wait a few more revs for MSVC before
allowing
> C++17, but given that it's becoming easier and easier to bump the
minimum
> MSVC version, I'm discounting this as a factor, as MSVC will not really
be
> the bottleneck in any real sense.
>
> On Tue, Oct 4, 2016 at 2:15 PM Mehdi Amini <mehdi.amini at
apple.com<http://apple.com/>> wrote:
>
>>
>> On Oct 4, 2016, at 2:10 PM, Reid Kleckner <rnk at
google.com<http://google.com/>> wrote:
>>
>> On Tue, Oct 4, 2016 at 11:58 AM, Mehdi Amini <mehdi.amini at
apple.com<http://apple.com/>>
>> wrote:
>>
>>>
>>> On Oct 4, 2016, at 8:40 AM, Reid Kleckner via llvm-dev <
>>> llvm-dev at lists.llvm.org<http://lists.llvm.org/>> wrote:
>>>
>>> On Tue, Oct 4, 2016 at 8:29 AM, Zachary Turner <zturner at
google.com<http://google.com/>>
>>> wrote:
>>>>
>>>> I ask because many of these LTS distros are notoriously slow at
updating
>>>> their packages. While some people may think C++14 doesn't
provide enough
>>>> bang for the buck to justify bumping to GCC 4.9, C++17
definitely does. But
>>>> at that point we're going to be talking about GCC 6.1 or
6.2, which is
>>>> going to be significantly harder unless we want to wait 5-7
years, and I
>>>> suspect people won't.
>>>>
>>>
>>> If by "notoriously slow" you mean they don't bump
their toolchain
>>> versions at all, then yeah. We just wait until the LTS release is
at
>>> end-of-life before dropping it.
>>>
>>>
>>> That’s the first time I read about this policy: we support every
linux
>>> LTS distribution till their end-of-life? Only Ubuntu? Do you have a
pointer
>>> where it is documented / discussed?
>>> (Note that Ubuntu LTS is 5 years AFAIK.)
>>>
>>
>> Sorry, I didn't mean to refer to the LTS support lifetime. I just
meant we
>> support the last LTS until we can reasonably expect users to have
upgraded
>> to the new one. If there's an LTS release every two years, then we
want to
>> keep supporting them for at least three years to give people a year to
>> upgrade.
>>
>>
>> OK, got it.
>>
>> Thanks for clarifying!
>>
>> Mehdi
>>
>>
_______________________________________________
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http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
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Firefox's experience is that GCC 5 isn't going to cut it, especially if you move to MSVC 2017, because people are going to be quickly annoyed at the lack of relaxed constexpr function support, which is GCC 6+. You can get GCC 6 for Ubuntu 16.04; I have it on my machine, though it's strangely not listed on packages.ubuntu.com for 16.04. -Nathan On Thu, May 10, 2018 at 3:20 PM, via llvm-dev <llvm-dev at lists.llvm.org> wrote:> Well… Ubuntu 16.04 came with gcc 5, and deploying Visual Studio 2015 should > be a done deal in Windows shops, which suggests moving to C++14 should be no > problem. > > > > It's nice to see this week's version of MSVC supports C++17 but deploying > through corporate IT can take a while. ("This week's version" because the > blog post is dated Monday.) > > --paulr > > > > From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of Zachary > Turner via llvm-dev > Sent: Thursday, May 10, 2018 3:00 PM > To: JF Bastien > Cc: via llvm-dev > Subject: Re: [llvm-dev] Using C++14 code in LLVM > > > > Consider me on board with the highest version we can come to an agreement on > :) > > > > > > On Thu, May 10, 2018 at 11:50 AM JF Bastien <jfbastien at apple.com> wrote: > > > > On May 10, 2018, at 11:35 AM, Zachary Turner <zturner at google.com> wrote: > > > > If it's the only thing we can agree then I'll take it, but I just worry that > 3 years from now we're going to start another 3 year discussion, so that any > actual move to C++17 would end up taking double the time. > > > > Such a fatalistic view, let’s trust ourselves to be better next time ;-) > > But seriously: we can learn from moving to C++14, and use what we’ve learned > to move to C++17 faster next time. Also consider the code churn we’ll > encounter as we fix incompatibilities with C++11 / C++14, drop unnecessary > code, upgrade various uses, that will happen regardless of moving to C++17 > and will take a little while to occur. There would be more of that type of > churn if we went straight to C++17. > > > > > > Are the issues specific to C++17 additions to the standard library? What if > you allow C++17 language features but not C++17 library features? I'm > guessing this is too simple though and isn't sufficient to avoid the > problems (which I don't know anything about, so you'll have to enlighten > me)? > > > > Mostly library so far, yes, but the GCC 6 support for C++17 language isn’t > great either: > > > > - New auto rules for direct-list-initialization > > - static_assert with no message > > - typename in a template template parameter > > - Nested namespace definition > > - Attributes for namespaces and enumerators > > - u8 character literals > > - Allow constant evaluation for all non-type template arguments > > - Fold Expressions > > - Unary fold expressions and empty parameter packs > > - __has_include in preprocessor conditional > > - Differing begin and end types in range-based for\ > > > > From: https://en.cppreference.com/w/cpp/compiler_support > > > > The only thing that’s really nice are fold expressions, and I hope they’re > not buggy in GCC 6. > > > > Otherwise the list is missing a good amount for C++17 language features, and > brings up the discussion of which GCC version is the minimum we mandate. I’d > rather avoid that discussion. Let’s assume GCC 6, if we get 7 then great, > but it doesn’t matter if we stick to C++14. > > > > > > On Thu, May 10, 2018 at 11:28 AM JF Bastien <jfbastien at apple.com> wrote: > > > > On May 10, 2018, at 11:22 AM, Zachary Turner <zturner at google.com> wrote: > > > > Windows has never been the issue. Honestly, MSVC on Windows is "fully C++17 > conformant" [1]. > > > > The issue has and always will be GCC. Given that a bump in any version of > GCC has been (and will remain) difficult for some time, I propose that we > skip C++14 and move to 17. We don't want to have a multi-year disccusion > about this again any time soon, and from what I gather, nobody has any more > reservations about moving to C++17 than they do about moving to C++14. They > only have reservations about moving to anything at all. So if we're gonna > move, we should go all the way. > > > > WebKit’s move to C++17 hasn’t been super smooth because of GCC / libstdc++ > issues in both GCC 6 and GCC 7. It’s all fixable, but given LLVM's slow move > out of C++11 I’d rather get C++14 now rather than a painful transition to > C++17 that drags on as we discover issues. > > > > > > Just my 2c. > > > > [1] > https://blogs.msdn.microsoft.com/vcblog/2018/05/07/announcing-msvc-conforms-to-the-c-standard/ > > > > On Thu, May 10, 2018 at 11:18 AM Eric Christopher <echristo at gmail.com> > wrote: > > Once again, I'm totally down for this and think we should do it. I worry > about windows, but ... > > > > Zach: How's windows c++14 support looking? > > > > -eric > > > > On Thu, May 10, 2018 at 10:01 AM JF Bastien via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > Hi folks! > > > > Six more months have come and gone, and maybe we could move LLVM to C++14 > now? > > > > The issues I picked out from the last discussion: > > Some folks want an official policy about compiler support before updating > the standard version we use. > Worries about which GCC version is available in which distro. > Worries about MSVC. > > > > Instead of rehashing the compiler per distro surveys from previous > discussion, and instead of talking bootstrap, let me offer three data > points: > > WebKit is moving to C++17 (from C++14) right now † > Chromium started moving to C++14 in August of last year > Firefox uses some C++14 > > What I get from this data: if your distro bundles a modern web browser, it > already builds some C++14, somehow. > > > > The LLVM community has been talking about this for a while now, and I’m not > aware of a policy coming to light. I don’t think we need a policy given the > above data. So how about we… just kinda... move LLVM to C++14? > > > > > > Thanks! > > > > JF > > > > > > † the move to C++17 is very painful, but 14 has been working great in WebKit > for quite a long time. > > > > > >> Last time we discussed this, the consensus was "I think we can survive > >> another year without generalized constexpr and variable templates". > >> > >> Well, we did indeed survive. And it's been exactly a year! So >> naturally, > >> it only makes sense to revive this :) > >> > >> > >> > >> There's an active conversation going on in IRC right now, and it seems >> like > >> there is more desire than there was last year. > >> > >> What are the main gains from allowing C++14? > >> * Variable templates > >> * Generalized constexpr > >> * Return-type Deduction > >> * Generic Lambdas > >> * std::make_unique<> (the source of many build bot breakages) > >> > >> > >> What are the main gains from allowing C++17? [1] > >> * [[nodiscard]] attribute > >> * structured bindings > >> * constexpr-if > >> * guaranteed copy elision > >> * numerous new library types: optional, string_view, variant, byte, > >> * numerous new algorithms: parallel algorithms, too many to list > >> * Probably some more, but I just tried to hit the biggest ones. > >> > >> > >> First, it seems like if we want to enable C++14 we need GCC >= 5. > >> And if we want to enable C++17 we need GCC >= 7. > >> > >> With that out of the way, here were some of the issues that were raised > >> last time: > >> > >> Issue: Ubuntu 14.04 LTS is on GCC 4.8.x, and we have to support it until > >> end of life. > >> Resolution: LTS is right around the corner, in 6 more months. > >> > >> Issue: Various other platforms have older GCCs as their system compiler, > >> and it's annoying to upgrade. > >> Question: Do any of these not have a port you can install? For example, > >> NetBSD 7 appears to have GCC 5.3 as a port, if DistroWatch is any > >> indication. It could be wrong though and I could also be misinterpreting > >> it. > >> > >> Issue: If we're going to make people bootstrap a compiler, we might as >> well > >> go all the way to C++17. > >> Comment: I'm not opposed. > >> > >> > >> Some questions / comments of my own: > >> > >> * Where is this policy about Ubuntu and LTS documented? Does this mean, > >> for example, that we will not be able to use C++17 until 2023 (16.04 LTS > >> has only GCC 5.3.1)? That seems a bit unreasonable. And there's no > >> guarantee that 18.04 LTS will even have GCC 7 or higher either, so it >> could > >> be 2025 or 2027. > >> > >> * We've asked people in the past to build a modern toolchain. For >> example, > >> we did it with C++11 and Ubuntu 12.04 LTS. Is C++17 compelling enough to > >> justify this again? > >> > >> * GCC 4.9 probably isn't sufficient to justify an increase for anyone, as > >> it lacks two of the more sought-after features of C++14 (variable >> templates > >> and generalized constexpr). So IMO we should require a bump to GCC 5 or > >> higher, or not at all. > >> > >> * Clang 6 supports all of C++20, and it builds with only C++11, so we > >> shouldn't have to worry too much about the problem of needing to "daisy > >> chain" compilers to finally get the latest version of LLVM building. "GCC > >> 4.8 -> Clang 6 - > Clang ToT" should hold up through C++1z. > >> > >> * While we obviously can't be tied to the versioning of every single >> distro > >> out there, some are "bigger" than others. Which are big enough that > >> warrant serious consideration? The ones I found are (and I did my best to > >> aggregate all this, but please correct me if anything is incorrect or > >> misrepresented): > >> > >> OpenBSD - Ships with GCC 4.2.1 anyway. They are already having to > >> bootstrap something, so the proposal here does not change anything, >> because > >> even current LLVM doesn't compile with GCC 4.2.1 > >> > >> CentOS & RHEL - No version of Distro, including trunk, has GCC >= 4.8.5 > >> (are there ports?) > >> > >> Debian - Minimum version 9 for GCC >= 5 (are there ports for earlier > >> releases?) > >> > >> Fedora - Minimum version 24 for GCC >= 5, minimum version 26 for GCC >= 7 > >> > >> Ubuntu - Minimum LTS 16.04 for GCC >= 5 > >> > >> NetBSD - Version 7 has GCC 4.8.4 by default, but contains port for 5.3.0 > >> > >> FreeBSD - Minimum Version 11 for GCC >= 5 > >> > >> So, thoughts? > >> > >> > >> [1] - Note that we'd need to wait a few more revs for MSVC before allowing > >> C++17, but given that it's becoming easier and easier to bump the minimum > >> MSVC version, I'm discounting this as a factor, as MSVC will not really be > >> the bottleneck in any real sense. > >> > >> On Tue, Oct 4, 2016 at 2:15 PM Mehdi Amini <mehdi.amini at apple.com> >> wrote: > >> > >>> > >>> On Oct 4, 2016, at 2:10 PM, Reid Kleckner <rnk at google.com> wrote: > >>> > >>> On Tue, Oct 4, 2016 at 11:58 AM, Mehdi Amini <mehdi.amini at apple.com> > >>> wrote: > >>> > >>>> > >>>> On Oct 4, 2016, at 8:40 AM, Reid Kleckner via llvm-dev < > >>>> llvm-dev at lists.llvm.org> wrote: > >>>> > >>>> On Tue, Oct 4, 2016 at 8:29 AM, Zachary Turner <zturner at google.com> > >>>> wrote: > >>>>> > >>>>> I ask because many of these LTS distros are notoriously slow at >>>>> updating > >>>>> their packages. While some people may think C++14 doesn't provide >>>>> enough > >>>>> bang for the buck to justify bumping to GCC 4.9, C++17 definitely does. >>>>> But > >>>>> at that point we're going to be talking about GCC 6.1 or 6.2, which is > >>>>> going to be significantly harder unless we want to wait 5-7 years, and >>>>> I > >>>>> suspect people won't. > >>>>> > >>>> > >>>> If by "notoriously slow" you mean they don't bump their toolchain > >>>> versions at all, then yeah. We just wait until the LTS release is at > >>>> end-of-life before dropping it. > >>>> > >>>> > >>>> That’s the first time I read about this policy: we support every linux > >>>> LTS distribution till their end-of-life? Only Ubuntu? Do you have a >>>> pointer > >>>> where it is documented / discussed? > >>>> (Note that Ubuntu LTS is 5 years AFAIK.) > >>>> > >>> > >>> Sorry, I didn't mean to refer to the LTS support lifetime. I just meant >>> we > >>> support the last LTS until we can reasonably expect users to have >>> upgraded > >>> to the new one. If there's an LTS release every two years, then we want >>> to > >>> keep supporting them for at least three years to give people a year to > >>> upgrade. > >>> > >>> > >>> OK, got it. > >>> > >>> Thanks for clarifying! > >>> > >>> Mehdi > >>> > >>> > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev > > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >
Jean-Michaël Celerier via llvm-dev
2018-May-11 08:37 UTC
[llvm-dev] Using C++14 code in LLVM
> It's nice to see this week's version of MSVC supports C++17 butdeploying through corporate IT can take a while. But this does apply to LLVM versions, to, doesn't it ? What's the problem with LLVM 9 using c++17 if you can only develop based on LLVM 5 at your shop anyways ? ------- Jean-Michaël Celerier http://www.jcelerier.name On Thu, May 10, 2018 at 9:20 PM, via llvm-dev <llvm-dev at lists.llvm.org> wrote:> Well… Ubuntu 16.04 came with gcc 5, and deploying Visual Studio 2015 > should be a done deal in Windows shops, which suggests moving to C++14 > should be no problem. > > > > It's nice to see this week's version of MSVC supports C++17 but deploying > through corporate IT can take a while. ("This week's version" because the > blog post is dated Monday.) > > --paulr > > > > *From:* llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] *On Behalf Of *Zachary > Turner via llvm-dev > *Sent:* Thursday, May 10, 2018 3:00 PM > *To:* JF Bastien > *Cc:* via llvm-dev > *Subject:* Re: [llvm-dev] Using C++14 code in LLVM > > > > Consider me on board with the highest version we can come to an agreement > on :) > > > > > > On Thu, May 10, 2018 at 11:50 AM JF Bastien <jfbastien at apple.com> wrote: > > > > On May 10, 2018, at 11:35 AM, Zachary Turner <zturner at google.com> wrote: > > > > If it's the only thing we can agree then I'll take it, but I just worry > that 3 years from now we're going to start another 3 year discussion, so > that any actual move to C++17 would end up taking double the time. > > > > Such a fatalistic view, let’s trust ourselves to be better next time ;-) > > But seriously: we can learn from moving to C++14, and use what we’ve > learned to move to C++17 faster next time. Also consider the code churn > we’ll encounter as we fix incompatibilities with C++11 / C++14, drop > unnecessary code, upgrade various uses, that will happen regardless of > moving to C++17 and will take a little while to occur. There would be more > of that type of churn if we went straight to C++17. > > > > > > Are the issues specific to C++17 additions to the standard library? What > if you allow C++17 language features but not C++17 library features? I'm > guessing this is too simple though and isn't sufficient to avoid the > problems (which I don't know anything about, so you'll have to enlighten > me)? > > > > Mostly library so far, yes, but the GCC 6 support for C++17 language isn’t > great either: > > > > - New auto rules for direct-list-initialization > > - static_assert with no message > > - typename in a template template parameter > > - Nested namespace definition > > - Attributes for namespaces and enumerators > > - u8 character literals > > - Allow constant evaluation for all non-type template arguments > > - Fold Expressions > > - Unary fold expressions and empty parameter packs > > - __has_include in preprocessor conditional > > - Differing begin and end types in range-based for\ > > > > From: https://en.cppreference.com/w/cpp/compiler_support > > > > The only thing that’s really nice are fold expressions, and I hope they’re > not buggy in GCC 6. > > > > Otherwise the list is missing a good amount for C++17 language features, > and brings up the discussion of which GCC version is the minimum we > mandate. I’d rather avoid that discussion. Let’s assume GCC 6, if we get 7 > then great, but it doesn’t matter if we stick to C++14. > > > > > > On Thu, May 10, 2018 at 11:28 AM JF Bastien <jfbastien at apple.com> wrote: > > > > On May 10, 2018, at 11:22 AM, Zachary Turner <zturner at google.com> wrote: > > > > Windows has never been the issue. Honestly, MSVC on Windows is "fully > C++17 conformant" [1]. > > > > The issue has and always will be GCC. Given that a bump in any version of > GCC has been (and will remain) difficult for some time, I propose that we > skip C++14 and move to 17. We don't want to have a multi-year disccusion > about this again any time soon, and from what I gather, nobody has any more > reservations about moving to C++17 than they do about moving to C++14. > They only have reservations about moving to anything at all. So if we're > gonna move, we should go all the way. > > > > WebKit’s move to C++17 hasn’t been super smooth because of GCC / libstdc++ > issues in both GCC 6 and GCC 7. It’s all fixable, but given LLVM's slow > move out of C++11 I’d rather get C++14 now rather than a painful transition > to C++17 that drags on as we discover issues. > > > > > > Just my 2c. > > > > [1] https://blogs.msdn.microsoft.com/vcblog/2018/05/07/ > announcing-msvc-conforms-to-the-c-standard/ > > > > On Thu, May 10, 2018 at 11:18 AM Eric Christopher <echristo at gmail.com> > wrote: > > Once again, I'm totally down for this and think we should do it. I worry > about windows, but ... > > > > Zach: How's windows c++14 support looking? > > > > -eric > > > > On Thu, May 10, 2018 at 10:01 AM JF Bastien via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > > Hi folks! > > > > Six more months have come and gone, and maybe we could move LLVM to C++14 > now? > > > > The issues I picked out from the last discussion: > > 1. Some folks want an official policy about compiler support before > updating the standard version we use. > 2. Worries about which GCC version is available in which distro. > 3. Worries about MSVC. > > > > Instead of rehashing the compiler per distro surveys from previous > discussion, and instead of talking bootstrap, let me offer three data > points: > > - WebKit is moving to C++17 > <https://lists.webkit.org/pipermail/webkit-dev/2018-March/029922.html> (from > C++14) right now † > - Chromium started moving to C++14 > <https://groups.google.com/a/chromium.org/d/msg/cxx/ow7hmdDm4yw/eV6KWL2yAQAJ> in > August of last year > - Firefox uses some C++14 > <https://developer.mozilla.org/en-US/docs/Mozilla/Using_CXX_in_Mozilla_code> > > What I get from this data: if your distro bundles a modern web browser, it > already builds some C++14, *somehow*. > > > > The LLVM community has been talking about this for a while now, and I’m > not aware of a policy coming to light. I don’t think we need a policy given > the above data. So how about we… just kinda... move LLVM to C++14? > > > > > > Thanks! > > > > JF > > > > > > † the move to C++17 is very painful, but 14 has been working great in > WebKit for quite a long time. > > > > > > > Last time we discussed this, the consensus was "I think we can survive > > > another year without generalized constexpr and variable templates". > > > > > > Well, we did indeed survive. And it's been exactly a year! So > naturally, > > > it only makes sense to revive this :) > > > > > > > > > > > > There's an active conversation going on in IRC right now, and it seems > like > > > there is more desire than there was last year. > > > > > > What are the main gains from allowing C++14? > > > * Variable templates > > > * Generalized constexpr > > > * Return-type Deduction > > > * Generic Lambdas > > > * std::make_unique<> (the source of many build bot breakages) > > > > > > > > > What are the main gains from allowing C++17? [1] > > > * [[nodiscard]] attribute > > > * structured bindings > > > * constexpr-if > > > * guaranteed copy elision > > > * numerous new library types: optional, string_view, variant, byte, > > > * numerous new algorithms: parallel algorithms, too many to list > > > * Probably some more, but I just tried to hit the biggest ones. > > > > > > > > > First, it seems like if we want to enable C++14 we need GCC >= 5. > > > And if we want to enable C++17 we need GCC >= 7. > > > > > > With that out of the way, here were some of the issues that were raised > > > last time: > > > > > > Issue: Ubuntu 14.04 LTS is on GCC 4.8.x, and we have to support it until > > > end of life. > > > Resolution: LTS is right around the corner, in 6 more months. > > > > > > Issue: Various other platforms have older GCCs as their system compiler, > > > and it's annoying to upgrade. > > > Question: Do any of these not have a port you can install? For example, > > > NetBSD 7 appears to have GCC 5.3 as a port, if DistroWatch is any > > > indication. It could be wrong though and I could also be misinterpreting > > > it. > > > > > > Issue: If we're going to make people bootstrap a compiler, we might as > well > > > go all the way to C++17. > > > Comment: I'm not opposed. > > > > > > > > > Some questions / comments of my own: > > > > > > * Where is this policy about Ubuntu and LTS documented? Does this mean, > > > for example, that we will not be able to use C++17 until 2023 (16.04 LTS > > > has only GCC 5.3.1)? That seems a bit unreasonable. And there's no > > > guarantee that 18.04 LTS will even have GCC 7 or higher either, so it > could > > > be 2025 or 2027. > > > > > > * We've asked people in the past to build a modern toolchain. For > example, > > > we did it with C++11 and Ubuntu 12.04 LTS. Is C++17 compelling enough to > > > justify this again? > > > > > > * GCC 4.9 probably isn't sufficient to justify an increase for anyone, as > > > it lacks two of the more sought-after features of C++14 (variable > templates > > > and generalized constexpr). So IMO we should require a bump to GCC 5 or > > > higher, or not at all. > > > > > > * Clang 6 supports all of C++20, and it builds with only C++11, so we > > > shouldn't have to worry too much about the problem of needing to "daisy > > > chain" compilers to finally get the latest version of LLVM building. > "GCC > > > 4.8 -> Clang 6 - > Clang ToT" should hold up through C++1z. > > > > > > * While we obviously can't be tied to the versioning of every single > distro > > > out there, some are "bigger" than others. Which are big enough that > > > warrant serious consideration? The ones I found are (and I did my best > to > > > aggregate all this, but please correct me if anything is incorrect or > > > misrepresented): > > > > > > OpenBSD - Ships with GCC 4.2.1 anyway. They are already having to > > > bootstrap something, so the proposal here does not change anything, > because > > > even current LLVM doesn't compile with GCC 4.2.1 > > > > > > CentOS & RHEL - No version of Distro, including trunk, has GCC >= 4.8.5 > > > (are there ports?) > > > > > > Debian - Minimum version 9 for GCC >= 5 (are there ports for earlier > > > releases?) > > > > > > Fedora - Minimum version 24 for GCC >= 5, minimum version 26 for GCC >= 7 > > > > > > Ubuntu - Minimum LTS 16.04 for GCC >= 5 > > > > > > NetBSD - Version 7 has GCC 4.8.4 by default, but contains port for 5.3.0 > > > > > > FreeBSD - Minimum Version 11 for GCC >= 5 > > > > > > So, thoughts? > > > > > > > > > [1] - Note that we'd need to wait a few more revs for MSVC before > allowing > > > C++17, but given that it's becoming easier and easier to bump the minimum > > > MSVC version, I'm discounting this as a factor, as MSVC will not really > be > > > the bottleneck in any real sense. > > > > > > On Tue, Oct 4, 2016 at 2:15 PM Mehdi Amini <mehdi.amini at apple.com> > wrote: > > > > > >> > > >> On Oct 4, 2016, at 2:10 PM, Reid Kleckner <rnk at google.com> wrote: > > >> > > >> On Tue, Oct 4, 2016 at 11:58 AM, Mehdi Amini <mehdi.amini at apple.com> > > >> wrote: > > >> > > >>> > > >>> On Oct 4, 2016, at 8:40 AM, Reid Kleckner via llvm-dev < > > >>> llvm-dev at lists.llvm.org> wrote: > > >>> > > >>> On Tue, Oct 4, 2016 at 8:29 AM, Zachary Turner <zturner at google.com> > > >>> wrote: > > >>>> > > >>>> I ask because many of these LTS distros are notoriously slow at > updating > > >>>> their packages. While some people may think C++14 doesn't provide > enough > > >>>> bang for the buck to justify bumping to GCC 4.9, C++17 definitely > does. But > > >>>> at that point we're going to be talking about GCC 6.1 or 6.2, which is > > >>>> going to be significantly harder unless we want to wait 5-7 years, > and I > > >>>> suspect people won't. > > >>>> > > >>> > > >>> If by "notoriously slow" you mean they don't bump their toolchain > > >>> versions at all, then yeah. We just wait until the LTS release is at > > >>> end-of-life before dropping it. > > >>> > > >>> > > >>> That’s the first time I read about this policy: we support every linux > > >>> LTS distribution till their end-of-life? Only Ubuntu? Do you have a > pointer > > >>> where it is documented / discussed? > > >>> (Note that Ubuntu LTS is 5 years AFAIK.) > > >>> > > >> > > >> Sorry, I didn't mean to refer to the LTS support lifetime. I just meant > we > > >> support the last LTS until we can reasonably expect users to have > upgraded > > >> to the new one. If there's an LTS release every two years, then we want > to > > >> keep supporting them for at least three years to give people a year to > > >> upgrade. > > >> > > >> > > >> OK, got it. > > >> > > >> Thanks for clarifying! > > >> > > >> Mehdi > > >> > > >> > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev > > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20180511/88dbf3c5/attachment.html>