<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Thu, Oct 29, 2020 at 4:50 PM Chris Tetreault via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<br><br>(side note: Chris: There's /something/ about your emails that isn't threading in gmail at least - not sure if it's something you're aware of/something you can do anything about, but figured I'd mention (hmm, looks like they thread correctly on the llvm-dev archive, so the headers are probably correct - the subject lines look the same, so I really don't know what gmail's doing with them))<br><br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p class="MsoNormal">I think this argument is the slippery slope in action. Just because we allowed the gn build system to be added previously, does not mean that we should allow a new build system now. And forbidding this build system now does not mean that
we must kick gn out of the repo.<u></u><u></u></p>
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<p class="MsoNormal">We should accept or reject Bazel on its merits alone, and not based on historical precedent.</p></div></div></blockquote><div><br></div><div>I don't entirely agree - I think it's worth asking whether there's significant differences between this and previous choices. Precedent has bearing to me - "slippery slope" is a fallacy that if we allow A we must allow B, specifically when B does not follow from A. That we allow gn doesn't necessarily mean we have to allow all build systems, or that we have to allow Bazel - they are different, but are they different in significant ways that matter I think is the question.<br><br>I think relevant questions to ask to avoid rehashing the same decisions would be:<br><br>What problems do you/we find with the gn integration, that we could learn from to avoid making similar mistakes?</div><div>Have there been problems/costs to the community with the gn integration that we'd like to avoid incurring more of?<br>Otherwise, are there things that make Bazel integration different from gn that might make it worse/different in terms of costs to the community?</div><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 lang="EN-US"><div class="gmail-m_951896926237219313WordSection1"><p class="MsoNormal"><u></u><u></u></p>
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<p class="MsoNormal"><b>From:</b> llvm-dev <<a href="mailto:llvm-dev-bounces@lists.llvm.org" target="_blank">llvm-dev-bounces@lists.llvm.org</a>>
<b>On Behalf Of </b>Zachary Turner via llvm-dev<br>
<b>Sent:</b> Thursday, October 29, 2020 4:11 PM<br>
<b>To:</b> Renato Golin <<a href="mailto:rengolin@gmail.com" target="_blank">rengolin@gmail.com</a>><br>
<b>Cc:</b> Mehdi Amini <<a href="mailto:aminim@google.com" target="_blank">aminim@google.com</a>>; LLVM Dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>>; Stella Laurenzo <<a href="mailto:laurenzo@google.com" target="_blank">laurenzo@google.com</a>>; Tres Popp <<a href="mailto:tpopp@google.com" target="_blank">tpopp@google.com</a>>;
Geoffrey Martin-Noble <<a href="mailto:gcmn@google.com" target="_blank">gcmn@google.com</a>>; Thomas Joerg <<a href="mailto:tjoerg@google.com" target="_blank">tjoerg@google.com</a>><br>
<b>Subject:</b> [EXT] Re: [llvm-dev] Contributing Bazel BUILD files similar to gn<u></u><u></u></p>
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<p class="MsoNormal">On Thu, Oct 29, 2020 at 12:49 PM Renato Golin via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org" target="_blank">llvm-dev@lists.llvm.org</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal">On Thu, 29 Oct 2020 at 19:16, David Blaikie <<a href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@gmail.com</a>> wrote:<u></u><u></u></p>
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<p class="MsoNormal">I /believe/ the idea is that, like gn, there are folks maintaining these build systems out of tree anyway - and having them in tree makes it easier to coordinate that effort, with the express intent of not burdening the general community
with their upkeep (like gn currently - the idea is that there's no burden on developers to update gn build files (& consequently bazel build files)).<u></u><u></u></p>
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<p class="MsoNormal">Perhaps the initial assumption about my concerns weren't well articulated. <u></u><u></u></p>
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<p class="MsoNormal">I get that those files would be "additional" and other developers won't need to care much about them. <u></u><u></u></p>
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<p class="MsoNormal">But what happens when people join the project with experience in Bazel and, instead of building pure LLVM with CMake, they start using Bazel for everything, just because they're used to it?<u></u><u></u></p>
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<p class="MsoNormal">Didn't the community already go through this exact discussion when gn was added? Let me ask a different question. If gn support was permitted, on what grounds should we refuse a different parallel build system? Either we should allow
people to contribute build systems upstream that they wish to maintain, or we should keep every buidl system other than CMake out of the tree. <u></u><u></u></p>
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