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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">This is perfect – thanks for the info, guys!
</span><span style="font-size:11.0pt;font-family:Wingdings;color:#1F497D">J</span><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"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">iestyn<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""> cfe-dev-bounces@cs.uiuc.edu [mailto:cfe-dev-bounces@cs.uiuc.edu]
<b>On Behalf Of </b>Douglas Gregor<br>
<b>Sent:</b> Monday, November 05, 2012 10:47 AM<br>
<b>To:</b> Alexander Kornienko<br>
<b>Cc:</b> cfe-dev@cs.uiuc.edu<br>
<b>Subject:</b> Re: [cfe-dev] #undefine cursors<o:p></o:p></span></p>
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<p class="MsoNormal">On Nov 4, 2012, at 5:11 PM, Alexander Kornienko <<a href="mailto:alexfh@google.com">alexfh@google.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">On Sat, Nov 3, 2012 at 2:43 PM, Matthieu Monrocq <<a href="mailto:matthieu.monrocq@gmail.com" target="_blank">matthieu.monrocq@gmail.com</a>> wrote:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">On Fri, Nov 2, 2012 at 10:34 PM, Iestyn Bleasdale-Shepherd <<a href="mailto:iestyn@valvesoftware.com" target="_blank">iestyn@valvesoftware.com</a>> wrote:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Hi,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">When using the libclang API, ‘#define’ statements yield cursors, but ‘#undefine’ statements do not.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Without a record of #undefines, I can’t determine which #defines are extant at any given point in the code, and am thus unable to fully determine dependencies between source
files.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Is it possible to determine which #defines are active for a given source location, or would the addition of #undefine cursors be a reasonable feature request for the libclang
API?<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">Thanks!<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#888888"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#888888">iestyn Bleasdale-Shepherd<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#888888"> <o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><br>
Well, you are lucky in that a good chunk of work went on recently into what was called "Macro History" whose goal is exactly to remember every single #define/#undef that a macro encountered in the pre-processing of the translation unit. Therefore, using this
macro history, it should be possible to extract this information.<br>
<br>
Unfortunately, I do not know the exact API, Alexander Kornienko initiated the work on this, so he probably followed it, I have added him in CC so he can help us figure out exactly where this feature stands.<span style="color:#888888"><br>
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<span class="hoenzb">-- Matthieu</span></span><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">Yep, there were a couple of related patches: <a href="http://llvm-reviews.chandlerc.com/rL162810">http://llvm-reviews.chandlerc.com/rL162810</a>, <a href="http://llvm-reviews.chandlerc.com/rL164610">http://llvm-reviews.chandlerc.com/rL164610</a>.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif""><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">If you want to have a read-only access to macro history in libclang, you'll probably need to forward these methods:<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial","sans-serif"">IdentifierInfo::hadMacroDefinition(), Preprocessor::getMacroInfoHistory(IdentifierInfo *), MacroInfo::getPreviousDefinition(), MacroInfo::getUndefLoc()<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">The longer-term goal here is to switch libclang's macro cursors over to the Preprocessor's MacroInfo, abolishing the "detailed preprocessor record" currently used by libclang.<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 class="apple-tab-span"> </span>- Doug<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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