<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p><br>
</p>
<br>
<div class="moz-cite-prefix">On 10/04/2017 03:48 PM, Rui Ueyama
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAJENXgv-CGWfYXd+h8HpiqgoqXrJqrggda_6Yek+E5sT4k+CSg@mail.gmail.com">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">On Wed, Oct 4, 2017 at 3:17 PM,
Davide Italiano <span dir="ltr"><<a
href="mailto:davide.italiano@gmail.com" target="_blank"
moz-do-not-send="true">davide.italiano@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div dir="auto"><span class="gmail-">
<div><br>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Oct 4, 2017 2:31 PM,
"Rui Ueyama via llvm-dev" <<a
href="mailto:llvm-dev@lists.llvm.org"
target="_blank" moz-do-not-send="true">llvm-dev@lists.llvm.org</a>>
wrote:<br type="attribution">
<blockquote
class="gmail-m_3155820309029941525quote"
style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<div
class="gmail-m_3155820309029941525quoted-text">On
Wed, Oct 4, 2017 at 2:19 PM, Philip
Reames <span dir="ltr"><<a
href="mailto:listmail@philipreames.com"
target="_blank"
moz-do-not-send="true">listmail@philipreames.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF">
<p>Our build system is setup to
deliberately use a very old
environment. We've found that's
one of the most reliable easy
ways to ensure we don't
accidentally introduce a
dependency on a newer system
library than intended. This
lets us ship prebuilt binaries
which run on a wide spectrum of
systems. We're going to chat
internally and check to see if
we can roll this forward a bit,
but supporting an older glibc is
definitely going to be somewhat
we want. Exactly *how* old
might be flexible, but I have to
check.</p>
<p>Rui, let me turn your question
around on you. What version of
glibc would you like to be our
minimum? And why? Is there a
good reason to move this
forward? </p>
</div>
</blockquote>
</div>
<div>I don't have a clear answer to your
question, and I don't think I'm a
person who can set a standard, but
maybe, 11 years is a bit too old. I
don't think we want to intentionally
break it, and if it can be supported
by adding a few lines to CMakeFiles,
we probably should. However, IMO, this
should be done by best-effort basis. I
don't think we need to immediately
revert a patch if broke a 11 year old
system.<br>
</div>
</div>
</div>
</div>
</blockquote>
</div>
</div>
</div>
<div dir="auto"><br>
</div>
</span>
<div dir="auto">I don't necessarily agree with the last
point.</div>
<div dir="auto">I think a policy would help here, and it
should be based on the number of annoyances supporting
an old version cause. This is akin to what we did for,
e.g. VS 2013. If supporting a old version doesn't
allow the project to reasonably move forward, we
should consider an upgrade. FWIW, in this case I don't
think the feature introduced is worth the bump, but
your mileage may vary.</div>
<div dir="auto">I'd like to add that "11 years old
system" means nothing. In fact, I think we should aim
supporting even older systems whenever possible.</div>
</div>
</blockquote>
<div><br>
</div>
<div>I agree that we should support old systems whenever
possible. There's no reason to intentionally break it, and
it is generally good if it works on a large number of
systems including old ones.</div>
<div><br>
</div>
<div>But speaking of this instance, I feel like reverting a
patch as well as other related patches immediately when
it's found it broke a very old system was a bit too hasty.
If we want to keep everything work with an old system all
the time, we should set up a buildbot with an old version
of an operating system. Otherwise, I think a more time
should be given to developers to discuss and fix an issue
in the main repository.</div>
</div>
</div>
</div>
</blockquote>
In retrospect, I think I agree. We were probably too quick to
revert here. When I asked Daniel to do so, I was working with the
flawed assumption that this was relevant for any REHL 6 based
distro, but I should have checked that more thoroughly before we
acted. <br>
<br>
<blockquote type="cite"
cite="mid:CAJENXgv-CGWfYXd+h8HpiqgoqXrJqrggda_6Yek+E5sT4k+CSg@mail.gmail.com">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<div> </div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div dir="auto">
<div dir="auto">Thanks,</div>
<div dir="auto"><br>
</div>
<div dir="auto">--</div>
<div dir="auto">Davide</div>
<div>
<div class="gmail-h5">
<div dir="auto"><br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto">
<div class="gmail_extra">
<div class="gmail_quote">
<blockquote
class="gmail-m_3155820309029941525quote"
style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div dir="ltr">
<div class="gmail_extra">
<div class="gmail_quote">
<div
class="gmail-m_3155820309029941525elided-text">
<blockquote class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div bgcolor="#FFFFFF">
<p>I think we need to establish
and document a minimum
supported version here. I'm
open to debating what that
version should be, but the
current lack of clarity is
clearly problematic. </p>
<p><span
class="gmail-m_3155820309029941525m_-3025106230746079029HOEnZb"><font
color="#888888"> </font></span></p>
<span
class="gmail-m_3155820309029941525m_-3025106230746079029HOEnZb"><font
color="#888888">
<p>Philip</p>
</font></span>
<p>p.s. Sorry about the
confusion earlier about
CentOS. I'd misunderstood an
statement in internal
conversation and repeated the
information without checking.
While true that the build
failed on a CentOS 6.4 system,
it was being built against a
non-default (older) glibc. <br>
</p>
<p>p.p.s. This brought up the
point internally that we
really should have a public
build bot for the
configuration we care about.
I need to talk that over
internally, but this seems
like something we can make
happen. <br>
</p>
<div>
<div
class="gmail-m_3155820309029941525m_-3025106230746079029h5">
<br>
<div
class="gmail-m_3155820309029941525m_-3025106230746079029m_7536378356922522841moz-cite-prefix">On
10/04/2017 12:38 PM, Rui
Ueyama via llvm-dev wrote:<br>
</div>
<blockquote type="cite">
<div dir="ltr">Serguei,
<div><br>
</div>
<div>glibc 2.5 was
released 11 years ago,
so I wonder what
operating system you
are using now.</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On
Wed, Oct 4, 2017 at
12:08 AM, Serguei
Katkov via llvm-dev <span
dir="ltr"><<a
href="mailto:llvm-dev@lists.llvm.org"
target="_blank"
moz-do-not-send="true">llvm-dev@lists.llvm.org</a>></span>
wrote:<br>
<blockquote
class="gmail_quote"
style="margin:0px
0px 0px
0.8ex;border-left:1px
solid
rgb(204,204,204);padding-left:1ex">
<div lang="EN-US">
<div
class="gmail-m_3155820309029941525m_-3025106230746079029m_7536378356922522841m_-5366148437303026918WordSection1">
<p
class="MsoNormal">Hi
All,</p>
<p
class="MsoNormal"> </p>
<p
class="MsoNormal">The
landed patch <a
href="https://reviews.llvm.org/D38481" target="_blank"
moz-do-not-send="true">https://reviews.llvm.org/D3848<wbr>1</a>
introduced the
usage of
CPU_COUNT
defined in
glibc sched.h
header.</p>
<p
class="MsoNormal">I
failed to find
this symbol in
sched.h of
glibc version
2.5-24, so
compilation
just fails.</p>
<p
class="MsoNormal"><span>/home/dolphin/merge-from-upstr<wbr>eam-area/ws/pristine/lib/Suppo<wbr>rt/Threading.cpp:
In function
‘unsigned int
llvm::hardware_concurrency()’:</span></p>
<p
class="MsoNormal"><span>/home/dolphin/merge-from-upstr<wbr>eam-area/ws/pristine/lib/Suppo<wbr>rt/Threading.cpp:80:26:
error:
‘CPU_COUNT’
was not
declared in
this scope</span></p>
<p
class="MsoNormal"><span>
return
CPU_COUNT(&Set);</span></p>
<p
class="MsoNormal"><span>
^</span></p>
<p
class="MsoNormal"> </p>
<p
class="MsoNormal">It
is buildable
with newest
version of
glibc. </p>
<p
class="MsoNormal">I
tried to find
a requirements
for glibc
version in
LLVM
documentation
but failed.</p>
<p
class="MsoNormal">So
I wonder
whether there
is such
requirement or
not.</p>
<p
class="MsoNormal">Could
anyone point
me to this
documentation?</p>
<p
class="MsoNormal"> </p>
<p
class="MsoNormal">I'm
trying to
understand
whether patch
is wrong which
relies on
availability
of library but
does not check
the symbol
itself or this
version of
glibc is not
supported.</p>
<p
class="MsoNormal"> </p>
<p
class="MsoNormal">Thank
you,</p>
<p
class="MsoNormal">Serguei.</p>
<p
class="MsoNormal"><span
lang="RU"> </span></p>
</div>
</div>
<br>
______________________________<wbr>_________________<br>
LLVM Developers
mailing list<br>
<a
href="mailto:llvm-dev@lists.llvm.org"
target="_blank"
moz-do-not-send="true">llvm-dev@lists.llvm.org</a><br>
<a
href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev"
rel="noreferrer"
target="_blank"
moz-do-not-send="true">http://lists.llvm.org/cgi-bin/<wbr>mailman/listinfo/llvm-dev</a><br>
<br>
</blockquote>
</div>
<br>
</div>
<br>
<fieldset
class="gmail-m_3155820309029941525m_-3025106230746079029m_7536378356922522841mimeAttachmentHeader"></fieldset>
<br>
<pre>______________________________<wbr>_________________
LLVM Developers mailing list
<a class="gmail-m_3155820309029941525m_-3025106230746079029m_7536378356922522841moz-txt-link-abbreviated" href="mailto:llvm-dev@lists.llvm.org" target="_blank" moz-do-not-send="true">llvm-dev@lists.llvm.org</a>
<a class="gmail-m_3155820309029941525m_-3025106230746079029m_7536378356922522841moz-txt-link-freetext" href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev" target="_blank" moz-do-not-send="true">http://lists.llvm.org/cgi-bin/<wbr>mailman/listinfo/llvm-dev</a>
</pre>
</blockquote>
<br>
</div>
</div>
</div>
</blockquote>
</div>
</div>
<br>
</div>
</div>
<br>
______________________________<wbr>_________________<br>
LLVM Developers mailing list<br>
<a href="mailto:llvm-dev@lists.llvm.org"
target="_blank" moz-do-not-send="true">llvm-dev@lists.llvm.org</a><br>
<a
href="http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev"
rel="noreferrer" target="_blank"
moz-do-not-send="true">http://lists.llvm.org/cgi-bin/<wbr>mailman/listinfo/llvm-dev</a><br>
<br>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
<br>
</body>
</html>