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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">We had a similar problem with using LLVM on the GPU @ AMD as many times errors were not known until post-ISel/Resource Allocation. Our solution was to embed
the errors in the resulting ISA and have the assembler/loader emit/error at that time.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">So this kind of API would be useful for more than just kernel development.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Micah
<o:p></o:p></span></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""> llvmdev-bounces@cs.uiuc.edu [mailto:llvmdev-bounces@cs.uiuc.edu]
<b>On Behalf Of </b>Quentin Colombet<br>
<b>Sent:</b> Tuesday, July 16, 2013 5:21 PM<br>
<b>To:</b> LLVM Developers Mailing List<br>
<b>Subject:</b> [LLVMdev] [RFC] Add warning capabilities in LLVM.<o:p></o:p></span></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"><o:p> </o:p></p>
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<p class="MsoNormal">I would like to start a discussion about error/warning reporting in LLVM and how we can extend the current mechanism to take advantage of clang capabilities.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">** Motivation **<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Currently LLVM provides a way to report error either directly (print to stderr) or by using a user defined error handler. For instance, in inline asm parsing, we can specify the diagnostic handler to report the errors in clang.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The basic idea would be to be able to do that for warnings too (and for other kind of errors?).<o:p></o:p></p>
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<p class="MsoNormal">A motivating example can be found with the following link where we want LLVM to be able to warn on the stack size to help developing kernels:<o:p></o:p></p>
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<p class="MsoNormal"><a href="http://llvm.org/bugs/show_bug.cgi?id=4072">http://llvm.org/bugs/show_bug.cgi?id=4072</a><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">By adding this capability, we would be able to have access to all the nice features clang provides with warnings:<o:p></o:p></p>
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<p class="MsoNormal">- Promote it to an error.<o:p></o:p></p>
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<p class="MsoNormal">- Ignore it.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">** Challenge **<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">To be able to take advantage of clang framework for warning/error reporting, warnings have to be associated with warning groups.<o:p></o:p></p>
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<p class="MsoNormal">Thus, we need a way for the backend to specify a front-end warning type.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">The challenge is, AFAICT (which is not much, I admit), that front-end warning types are statically handled using tablegen representation.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">** Advices Needed **<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">1. Decide whether or not we want such capabilities (if we do not we may just add sporadically the support for a new warning/group of warning/error).<o:p></o:p></p>
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<p class="MsoNormal">2. Come up with a plan to implement that (assuming we want it).<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Thanks for the feedbacks.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Cheers,<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-family:"Helvetica","sans-serif";color:black">-Quentin<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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