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<p class="MsoNormal" style="margin-left:.5in">There are known problems with running IWYU over LLVM/Clang -- Zachary<br>
Turner made an attempt a while back to get it up and running. Since<br>
the LLVM tree uses all sorts of modern and moderately complex<br>
patterns, we're struggling to keep up<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Re-implementing IWYU based on Clang tooling seems like it would help a lot with that kind of problem.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">--paulr<o:p></o:p></span></p>
<p class="MsoNormal"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></a></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> cfe-dev [mailto:cfe-dev-bounces@lists.llvm.org]
<b>On Behalf Of </b>Mikhail Zolotukhin via cfe-dev<br>
<b>Sent:</b> Monday, December 11, 2017 12:37 PM<br>
<b>To:</b> Kim Gräsman<br>
<b>Cc:</b> llvm-dev; Clang Dev; Chris Lattner<br>
<b>Subject:</b> Re: [cfe-dev] [llvm-dev] Who wants faster LLVM/Clang builds?<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Hi Kim,<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">On Dec 10, 2017, at 7:39 AM, Kim Gräsman <<a href="mailto:kim.grasman@gmail.com">kim.grasman@gmail.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal">Hi Michael,<br>
<br>
On Thu, Dec 7, 2017 at 3:16 AM, Michael Zolotukhin<br>
<<a href="mailto:mzolotukhin@apple.com">mzolotukhin@apple.com</a>> wrote:<br>
<br>
<o:p></o:p></p>
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Nice to IWYU developers here:) I wonder how hard it would be to run IWYU on<br>
LLVM/Clang (or, if it’s supposed to work, I wonder what I did wrong).<o:p></o:p></p>
<p class="MsoNormal"><br>
There are known problems with running IWYU over LLVM/Clang -- Zachary<br>
Turner made an attempt a while back to get it up and running. Since<br>
the LLVM tree uses all sorts of modern and moderately complex<br>
patterns, we're struggling to keep up.<o:p></o:p></p>
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<p class="MsoNormal">I see.<br>
<br>
<o:p></o:p></p>
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<p class="MsoNormal"><br>
<br>
<o:p></o:p></p>
<p class="MsoNormal">If we also can tweak it a bit to make it choose more human-like (~more<br>
conservative) decisions, we would be able to just apply what it suggests!<o:p></o:p></p>
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Different humans appear to have different preferences :)<o:p></o:p></p>
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<p class="MsoNormal">True, what I meant hear is to make the changes more conservative: e.g. if we can replace<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Menlo","serif"">#include "MyClass.h"</span><o:p></o:p></p>
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<p class="MsoNormal">with <o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Menlo","serif"">class MyClass;</span><o:p></o:p></p>
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<p class="MsoNormal">then this change is probably desirable in every way: it documents the code better, it decreases coupling, it improves compile time.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">But if for instance we suggest replacing it with<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Menlo","serif"">#include "BaseClass1.h" // previously included from MyClass.h</span><o:p></o:p></p>
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<p class="MsoNormal"><span style="font-family:"Menlo","serif"">#include "ExtraStuffForMyClass.h"</span><o:p></o:p></p>
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<p class="MsoNormal">then it's less straight-forward, at least from the code-selfdocumentation point of view.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">If we could make IWYU to only suggest changes of the first type, then we probably could've just blindly apply all the suggested changes.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><br>
It'd be great to hear more about specifics, maybe you can bring them<br>
up on the IWYU list:<br>
<a href="https://groups.google.com/forum/#!forum/include-what-you-use?">https://groups.google.com/forum/#!forum/include-what-you-use?</a><o:p></o:p></p>
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<p class="MsoNormal">Will do, 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">Michael<br>
<br>
<o:p></o:p></p>
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<p class="MsoNormal"><br>
Some of IWYU's controversial changes are by design, but some are just<br>
bugs, and if you have ideas for a more principled design, we<br>
appreciate all the input we can get.<br>
<br>
Thanks,<br>
- Kim<o:p></o:p></p>
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