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<p class="MsoNormal">I find out-of-tree builds useful so I can build multiple flangs without having to build multiple llvms.<o:p></o:p></p>
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<p class="MsoNormal">Tim<o:p></o:p></p>
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<p class="MsoNormal"><b><span style="font-size:12.0pt;color:black">From: </span></b><span style="font-size:12.0pt;color:black">flang-dev <flang-dev-bounces@lists.llvm.org> on behalf of Mehdi AMINI via flang-dev <flang-dev@lists.llvm.org><br>
<b>Reply-To: </b>Mehdi AMINI <joker.eph@gmail.com><br>
<b>Date: </b>Monday, May 4, 2020 at 10:31 AM<br>
<b>To: </b>David Truby <David.Truby@arm.com><br>
<b>Cc: </b>Flang Development List <flang-dev@lists.llvm.org><br>
<b>Subject: </b>Re: [flang-dev] CMake standalone and compile flags<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="font-size:7.5pt;font-family:"Verdana",sans-serif;color:black">External email: Use caution opening links or attachments</span></b><span style="font-size:7.5pt;font-family:"Verdana",sans-serif;color:black">
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<p class="MsoNormal">On Mon, May 4, 2020 at 10:17 AM David Truby <<a href="mailto:David.Truby@arm.com">David.Truby@arm.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Hi Mehdi,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">That branch enables out of tree builds; I believe there are people that still rely on those which is why we added that branch in when rewriting the CMake infrastructure.<o:p></o:p></span></p>
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<p class="MsoNormal">I assume that folks were relying on this before the merge in the monorepo, but are there still reason to maintain this from now on? Can we put an end-date on it?<o:p></o:p></p>
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<p class="MsoNormal">I'm trying to figure out if this is just a transition thing or if this is really something useful on the long run (and why).<o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">There's an open review to fix a similar issue as is reported in the discussion you linked but it seems to have stalled on a discussion about whether to continue to force Werror on, perhaps you
could take a look at that and comment there if it fixes this issue or not?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">The review is at <a href="https://reviews.llvm.org/D78306" target="_blank">
https://reviews.llvm.org/D78306</a><o:p></o:p></span></p>
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<p class="MsoNormal">Thanks, that was roughly what I was about to start doing!<o:p></o:p></p>
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<p class="MsoNormal">In general I think we should avoid doing directly `set(CMAKE_CXX_FLAGS ...` and instead use the `add_flag_if_supported` macros provided by LLVM, e.g.: <a href="https://github.com/llvm/llvm-project/blob/master/mlir/lib/CMakeLists.txt#L2">https://github.com/llvm/llvm-project/blob/master/mlir/lib/CMakeLists.txt#L2</a><o:p></o:p></p>
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<p class="MsoNormal">Werror is always difficult to maintain because different compilers (and compiler versions) have different handling (possibly even opposite!) warnings. It is a good thing to have for developers, but it may be a bit hostile to users to have
it on by default.<o:p></o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
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<p class="MsoNormal">Mehdi<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">Thanks<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:12.0pt;color:black">David Truby<o:p></o:p></span></p>
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<p class="MsoNormal"><b><span style="color:black">From:</span></b><span style="color:black"> flang-dev <<a href="mailto:flang-dev-bounces@lists.llvm.org" target="_blank">flang-dev-bounces@lists.llvm.org</a>> on behalf of Mehdi AMINI via flang-dev <<a href="mailto:flang-dev@lists.llvm.org" target="_blank">flang-dev@lists.llvm.org</a>><br>
<b>Sent:</b> 04 May 2020 18:12<br>
<b>To:</b> Flang Development List <<a href="mailto:flang-dev@lists.llvm.org" target="_blank">flang-dev@lists.llvm.org</a>><br>
<b>Subject:</b> [flang-dev] CMake standalone and compile flags</span> <o:p></o:p></p>
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<p class="MsoNormal"> <o:p></o:p></p>
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<p class="MsoNormal">Hi, <o:p></o:p></p>
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<p class="MsoNormal">I was looking into fixing this error that someone has when building flang: <a href="https://llvm.discourse.group/t/error-when-building-with-cmake/935" target="_blank">https://llvm.discourse.group/t/error-when-building-with-cmake/935</a><o:p></o:p></p>
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<p class="MsoNormal">Then I noticed that flang/CMakeLists.txt still has this branch: <a href="https://github.com/llvm/llvm-project/blob/master/flang/CMakeLists.txt#L42" target="_blank">https://github.com/llvm/llvm-project/blob/master/flang/CMakeLists.txt#L42</a>
; is there anyone that relies on it or can we simplify this file and the way the options are setup?<o:p></o:p></p>
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<p class="MsoNormal">Thanks,<o:p></o:p></p>
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<p class="MsoNormal">-- <o:p></o:p></p>
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<p class="MsoNormal">Mehdi<o:p></o:p></p>
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