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<p class="MsoNormal">At my previous workplace, we had a codebase that was 100% completely formatted via clang-format. I had a coworker that *<b>hated</b>* the local style. However, since we had complete coverage, he was able to set up git hooks to run clang-format
to reformat the codebase to his preferred style on checkout and back on commit. He was only able to do this because the coverage was complete.<o:p></o:p></p>
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<p class="MsoNormal">This doesn’t help with the merge conflict issue, but it definitely helps with the “clang-format does this thing that I don’t like” issue. However, until we finish formatting the codebase, nobody can do this.<o:p></o:p></p>
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<p class="MsoNormal"><b>From:</b> llvm-dev <llvm-dev-bounces@lists.llvm.org> <b>On Behalf Of
</b>Hal Finkel via llvm-dev<br>
<b>Sent:</b> Tuesday, June 30, 2020 11:12 AM<br>
<b>To:</b> Matt Arsenault <arsenm2@gmail.com>; MyDeveloper Day <mydeveloperday@gmail.com><br>
<b>Cc:</b> llvm-dev <llvm-dev@lists.llvm.org><br>
<b>Subject:</b> [EXT] Re: [llvm-dev] [RFC] Semi-Automatic clang-format of files with low frequency<o:p></o:p></p>
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<p class="MsoNormal">On 6/30/20 12:55 PM, Matt Arsenault via llvm-dev wrote:<o:p></o:p></p>
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<p class="MsoNormal">On Jun 28, 2020, at 11:30, MyDeveloper Day via llvm-dev <<a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a>> wrote:<o:p></o:p></p>
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<span style="font-size:11.5pt;font-family:"Helvetica",sans-serif">I’m a contributor to clang-format and would like to see LLVM 100% clang formatted so we can use LLVM as a massive test-suite for clang-format when we make changes.<o:p></o:p></span></p>
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<p class="MsoNormal">My main issue with this would be that clang-format does things that I don’t believe are stated in the LLVM style guide and I also disagree with. There’s a whole set of cases where it makes unwelcome changes to put things that were on separate
lines on a single line. Whenever I run clang-format, I typically git checkout -p to discard all of these.<o:p></o:p></p>
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<p class="MsoNormal">For example, it likes to take member initializer lists and pack them into as few lines as possible. This is just asking for merge conflicts (e.g. AMDGPUSubtarget has a ton of fields in it, and out of tree code is constantly adding new fields
for unreleased subtargets). It also mangles BuildMI calls, where I believe every .add() should be on its own line, and stringing this into BuildMI().addFoo().addBar() is way less readable.<o:p></o:p></p>
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<p>I agree that this is problematic. There are a number of places where repeated syntactic structures (e.g., in enums, initializers, chained-operator invocation) are represented using regular line offsets and line breaks. This is valuable, allows for semantically-relevant
grouping, and in my opinion, enhances readability. I've certainly caught bugs in code that I've written because they became obvious once I lined everything up. Can clang-format be taught to format things in this way? For particular, long sections of code,
I can imagine using some don't-format-here markers, but you wouldn't want these around every BuildMI(...) call.<o:p></o:p></p>
<p> -Hal<o:p></o:p></p>
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<p class="MsoNormal">I also believe it’s 4 space indent on line wraps differs from the stated 2 space indent level (and this also disagrees with emacs llvm-style)<o:p></o:p></p>
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<p class="MsoNormal">-Matt<o:p></o:p></p>
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<pre>_______________________________________________<o:p></o:p></pre>
<pre>LLVM Developers mailing list<o:p></o:p></pre>
<pre><a href="mailto:llvm-dev@lists.llvm.org">llvm-dev@lists.llvm.org</a><o:p></o:p></pre>
<pre><a href="https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev">https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev</a><o:p></o:p></pre>
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<pre>-- <o:p></o:p></pre>
<pre>Hal Finkel<o:p></o:p></pre>
<pre>Lead, Compiler Technology and Programming Languages<o:p></o:p></pre>
<pre>Leadership Computing Facility<o:p></o:p></pre>
<pre>Argonne National Laboratory<o:p></o:p></pre>
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