<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><br class=""><div><br class=""><blockquote type="cite" class=""><div class="">On Mar 27, 2019, at 17:56, JF Bastien via libcxx-dev <<a href="mailto:libcxx-dev@lists.llvm.org" class="">libcxx-dev@lists.llvm.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none; float: none; display: inline !important;" class="">libc++-dev is probably a better list for this discussion. Moving cfe-dev to BCC...</span><br class="" style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;"><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><br class=""><blockquote type="cite" class=""><div class="">On Mar 27, 2019, at 2:53 PM, Brian M. Rzycki <<a href="mailto:brzycki@gmail.com" class="">brzycki@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div class="gmail_default" style="font-family: monospace, monospace;">I've bisected down the previously mentioned commit deltas to the following commit. This is the first instance of the warning message.</div><div class="gmail_default" style="font-family: monospace, monospace;"><br class=""></div><div class="gmail_default" style="font-family: monospace, monospace;"><a href="https://github.com/llvm/llvm-project/commit/21450545d14" class="">https://github.com/llvm/llvm-project/commit/21450545d14</a> </div><div class="gmail_default" style="font-family: monospace, monospace;"><br class=""></div><p class="gmail-commit-title" style="box-sizing: border-box; margin: 0px 0px 8px; color: rgb(5, 38, 76); font-size: 18px; font-weight: 600; font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";">[libc++] decoupling Freestanding atomic<T> from libatomic.a</p><div class="gmail-commit-desc" style="box-sizing: border-box; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol"; font-size: 14px;"><pre class="" style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; font-size: 13px; margin-bottom: 0px; margin-top: 10px; color: rgb(68, 77, 86); line-height: 1.45; max-width: 100%; white-space: pre-wrap; overflow: visible;">This patch introduces non-lockfree atomics that do not require using
an external libatomic. This work is done with the long-term goal of
allowing the use of <atomic> in freestanding environments.
Thanks to Olivier Giroux for the patch.
Differential Revision: <a href="https://reviews.llvm.org/D56913" rel="nofollow" class="" style="box-sizing: border-box; background-color: transparent; color: rgb(3, 102, 214);">https://reviews.llvm.org/D56913</a>
</pre></div><div class="gmail_default" style="font-family: monospace, monospace;"><span class="" style="color: rgb(68, 77, 86); font-family: SFMono-Regular, Consolas, "Liberation Mono", Menlo, Courier, monospace; font-size: 13px; white-space: pre-wrap;">llvm-svn: 355318</span></div></div></div></blockquote></div></div></blockquote><div><br class=""></div><div>That commit doesn't touch the CMake scripts, so I admit I'm a little bit confused.</div><div><br class=""></div><div>Louis</div><br class=""><blockquote type="cite" class=""><div class=""><div style="caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: none;" class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class="gmail_default" style="font-family: monospace, monospace;"> <br class=""></div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Mar 27, 2019 at 3:43 PM Brian M. Rzycki <<a href="mailto:brzycki@gmail.com" class="">brzycki@gmail.com</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div dir="ltr" class=""><div class="gmail_default" style="font-family: monospace, monospace;">Sorry, I wasn't clear. I meant the change is somewhere between those two commits: those are two nightly builds 24 hours apart.</div></div><br class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Mar 27, 2019 at 3:08 PM JF Bastien <<a href="mailto:jfbastien@apple.com" target="_blank" class="">jfbastien@apple.com</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;"><div class=""><br class=""><div class=""><br class=""><blockquote type="cite" class=""><div class="">On Mar 27, 2019, at 12:59 PM, Brian M. Rzycki via cfe-dev <<a href="mailto:cfe-dev@lists.llvm.org" target="_blank" class="">cfe-dev@lists.llvm.org</a>> wrote:</div><br class="gmail-m_-2714281943330344387gmail-m_-905194210222011549Apple-interchange-newline"><div class=""><div dir="ltr" class=""><div dir="ltr" class=""><div class="gmail_default"><font face="monospace, monospace" class="">Hello Krzysztof,</font></div><div class="gmail_default"><font face="monospace, monospace" class=""><br class=""></font></div><div class="gmail_default"><font face="monospace, monospace" class="">I've seen these errors in our nightly builds as well and noticed them when tracking down a different set of build breaks last month. I don't honestly know if they can be safely ignored. Our nightly compilers work for our testing even with the errors. I would be interested in knowing what this means and if it impacts us though.</font></div><div class="gmail_default"><font face="monospace, monospace" class=""><br class=""></font></div><div class="gmail_default"><font face="monospace, monospace" class="">I did a little digging and found when we started seeing the messages. These SHAs are from the LLVM monorepo (<a href="https://github.com/llvm/llvm-project.git" rel="noreferrer" target="_blank" class="">https://github.com/llvm/llvm-project.git</a>). We started seeing them in our builds 2019-March-05. I don't have the exact commit but may have time tomorrow to dig in a bit more.</font></div><font face="monospace, monospace" class=""><br class="">b306ef12f04635-master (llvm-svn: 355299)<span class="Apple-converted-space"> </span><span class="gmail_default" style="font-family: monospace, monospace;"></span>#<span class="Apple-converted-space"> </span><span class="gmail_default" style="font-family: monospace, monospace;">clean</span><br class="">81dbc02671b223-master (llvm-svn: 355375)<span class="Apple-converted-space"> </span><span class="gmail_default" style="font-family: monospace, monospace;"></span>#<span class="Apple-converted-space"> </span><span class="gmail_default" style="font-family: monospace, monospace;">emits</span><span class="gmail_default" style="font-family: monospace, monospace;"></span><span class="gmail_default" style="font-family: monospace, monospace;"></span><span class="Apple-converted-space"> </span>"Host compiler must support std::atomic!”</font></div></div></div></blockquote><div class=""><br class=""></div><div class="">This change?</div></div><blockquote class="" style="margin: 0px 0px 0px 40px; border: none; padding: 0px;"><div class=""><div class=""><a href="https://github.com/llvm/llvm-project/commit/81dbc02671b223" target="_blank" class="">https://github.com/llvm/llvm-project/commit/81dbc02671b223</a></div></div></blockquote><div class=""><div class="">It’s an LLDB commit, doesn’t seem related. Maybe an adjacent change was the root cause?</div><div class=""><br class=""></div><br class=""><blockquote type="cite" class=""><div class=""><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Mar 27, 2019 at 1:20 PM Krzysztof Parzyszek via cfe-dev <<a href="mailto:cfe-dev@lists.llvm.org" target="_blank" class="">cfe-dev@lists.llvm.org</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-style: solid; border-left-color: rgb(204, 204, 204); padding-left: 1ex;">I'm seeing the following warning during cmake. I'm not sure when it started. Is this a known issue? Can it be safely ignored?<br class=""><br class="">CMake Warning at projects/libcxx/cmake/Modules/CheckLibcxxAtomic.cmake:49 (message):<br class=""> Host compiler must support std::atomic!<br class="">Call Stack (most recent call first):<br class=""> projects/libcxx/cmake/config-ix.cmake:63 (include)<br class=""> projects/libcxx/CMakeLists.txt:476 (include)<br class=""><br class="">It's also showing up in the upstream bots:<br class=""><a href="http://lab.llvm.org:8011/builders/libcxx-libcxxabi-x86_64-linux-debian/builds/1189/steps/cmake/logs/stdio" rel="noreferrer" target="_blank" class="">http://lab.llvm.org:8011/builders/libcxx-libcxxabi-x86_64-linux-debian/builds/1189/steps/cmake/logs/stdio</a><br class=""><br class="">The linker errors (in my cmake) are actually:<br class="">CMakeFiles/cmTC_354e0.dir/src.cxx.o: In function `__clang_call_terminate':<br class="">src.cxx:(.text.__clang_call_terminate[__clang_call_terminate]+0x2): undefined reference to `__cxa_begin_catch'<br class="">src.cxx:(.text.__clang_call_terminate[__clang_call_terminate]+0xb): undefined reference to `std::terminate()'<br class="">CMakeFiles/cmTC_354e0.dir/src.cxx.o:(.data.DW.ref.__gxx_personality_v0[DW.ref.__gxx_personality_v0]+0x0): undefined reference to `__gxx_personality_v0'<br class="">clang-8: error: linker command failed with exit code 1 (use -v to see invocation)<br class="">CMakeFiles/cmTC_354e0.dir/build.make:97: recipe for target 'cmTC_354e0' failed<br class=""><br class="">--<span class="Apple-converted-space"> </span><br class="">Krzysztof Parzyszek <span class="Apple-converted-space"> </span><a href="mailto:kparzysz@quicinc.com" target="_blank" class="">kparzysz@quicinc.com</a> LLVM compiler development<br class=""><br class="">_______________________________________________<br class="">cfe-dev mailing list<br class=""><a href="mailto:cfe-dev@lists.llvm.org" target="_blank" class="">cfe-dev@lists.llvm.org</a><br class=""><a href="https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev" rel="noreferrer" target="_blank" class="">https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev</a><br class=""></blockquote></div>_______________________________________________<br class="">cfe-dev mailing list<br class=""><a href="mailto:cfe-dev@lists.llvm.org" target="_blank" class="">cfe-dev@lists.llvm.org</a><br class=""><a href="https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev" target="_blank" class="">https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-dev</a><br class=""></div></blockquote></div><br class=""></div></blockquote></div></blockquote></div></div></blockquote></div><br class="" style="caret-color: rgb(0, 0, 0); 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