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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The language says things in an anonymous namespace are automatically imported into the containing scope. The question is whether the compiler expects the debugger
to know that a-priori.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The compiler can let the debugger off the hook by emitting an explicit import. Source fidelity requires that the import be marked artificial, because it's implicit
in the source, rather than explicit; one of those "as if" things.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Or, the compiler can require the debugger to know more about how the language works, and not emit the explicit import.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Either way is legal DWARF, and has no source-fidelity issues, but the former doesn't leave one particular language detail up to the debugger to get right.<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>
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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""> llvm-commits-bounces@cs.uiuc.edu [mailto:llvm-commits-bounces@cs.uiuc.edu]
<b>On Behalf Of </b>David Blaikie<br>
<b>Sent:</b> Tuesday, March 03, 2015 9:44 AM<br>
<b>To:</b> reviews+D7895+public+7827be49c0b04087@reviews.llvm.org<br>
<b>Cc:</b> llvm-commits@cs.uiuc.edu; Romanova, Katya<br>
<b>Subject:</b> Re: [PATCH] Anonymous namespaces are missing import DW_TAG_imported_module.<o:p></o:p></span></p>
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<p class="MsoNormal">On Fri, Feb 27, 2015 at 5:28 PM, Paul Robinson <<a href="mailto:Paul_Robinson@playstation.sony.com" target="_blank">Paul_Robinson@playstation.sony.com</a>> wrote:<o:p></o:p></p>
<p class="MsoNormal">It's an arguable gray area in the compiler/debugger contract. How much<br>
does the compiler _require_ the debugger to know? (Which is different<br>
from how much the debugger knows for the purpose of improving the user's<br>
debugging experience.)<o:p></o:p></p>
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I don't quite see the grey here - I thought the line of reasoning you've provided in the past was fairly simple: source fidelity. The source doesn't have a using directive in it, so I don't know why we'd expect to see one in the debug info.<br>
<o:p></o:p></p>
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<p class="MsoNormal">This change reduces that requirement, with very low size cost (which we<br>
are pretty sensitive to). A debugger that auto-imports anonymous<br>
namespaces will see the import and recognize that it has already imported<br>
that scope, so the cost there is also very low.<br>
<br>
Not seeing a whole lot of down-side here.<o:p></o:p></p>
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<p class="MsoNormal"><br>
Mostly just principles & a desire not to add cruft in source or output.<br>
<br>
Not sure if other people have any opinion on this, I'm happy to defer.<br>
<o:p></o:p></p>
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<br>
<a href="http://reviews.llvm.org/D7895" target="_blank">http://reviews.llvm.org/D7895</a><br>
<br>
EMAIL PREFERENCES<br>
<a href="http://reviews.llvm.org/settings/panel/emailpreferences/" target="_blank">
http://reviews.llvm.org/settings/panel/emailpreferences/</a><br>
<br>
<o:p></o:p></p>
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