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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The as-if suggests that an explicit artificial import is an entirely appropriate, natural and good way to handle it, because it models the language behavior
exactly without *requiring* additional smarts on the debugger side.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Not all as-if statements have to be modeled directly in the DWARF, because they aren't relevant to DWARF or DWARF has other ways of achieving the same effect.
For example, [namespace.udir]/2 says a using-directive means "the names appear <b>
as if<i> </i></b>they were declared in the nearest enclosing namespace…" but there's no reason to generate piles of declarations in the outer namespace because, we have DW_TAG_imported_module which means exactly that.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I don't see any good reason for artificial namespaces to be treated specially just because the namespace is anonymous and the 'using' directive isn't explicit
in the source.<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""> David Blaikie [mailto:dblaikie@gmail.com]
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<b>Sent:</b> Tuesday, August 18, 2015 10:27 AM<br>
<b>To:</b> Robinson, Paul<br>
<b>Cc:</b> reviews+D7895+public+7827be49c0b04087@reviews.llvm.org; Romanova, Katya; Eric Christopher; Frédéric Riss; Duncan P. N. Exon Smith; llvm-commits<br>
<b>Subject:</b> Re: [PATCH] D7895: Anonymous namespaces are missing import DW_TAG_imported_module.<o:p></o:p></span></p>
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<p class="MsoNormal">On Tue, Aug 18, 2015 at 10:23 AM, Robinson, Paul <<a href="mailto:Paul_Robinson@playstation.sony.com" target="_blank">Paul_Robinson@playstation.sony.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">| suggests that DW_TAG_imported_module could be used for C++ using directives (of which there are none in the source code in question).<o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><a name="14f41d6744d7520b__MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span></a><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">[namespace.unnamed]/1 says there is an implicit (as-if) using directive.</span><o:p></o:p></p>
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<p class="MsoNormal">Lots of things are as-if, doesn't mean we model them in the DWARF that way, it's just an easy way of defining the behavior in terms of other stuff that's already defined in the standard. Generally we try to model things like the actual
source where possible, it seems/usually sounds like/etc.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">--paulr</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"> </span><o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><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""> David Blaikie [mailto:<a href="mailto:dblaikie@gmail.com" target="_blank">dblaikie@gmail.com</a>]
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<b>Sent:</b> Tuesday, August 18, 2015 10:15 AM</span><o:p></o:p></p>
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<b>To:</b> Robinson, Paul<br>
<b>Cc:</b> <a href="mailto:reviews%2BD7895%2Bpublic%2B7827be49c0b04087@reviews.llvm.org" target="_blank">
reviews+D7895+public+7827be49c0b04087@reviews.llvm.org</a>; Romanova, Katya; Eric Christopher; Frédéric Riss; Duncan P. N. Exon Smith; llvm-commits<br>
<b>Subject:</b> Re: [PATCH] D7895: Anonymous namespaces are missing import DW_TAG_imported_module.<o:p></o:p></p>
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<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">All I'm saying is that I think this is a fine thing to have as a debugger-specific tuning for your debugger.<br>
<br>
DWARF-the-standard is language neutral, yes, so it provides features that can be used to describe many different languages. It describes (non-normatively) possible uses of DWARF features for language features, and suggests that DW_TAG_imported_module could
be used for C++ using directives (of which there are none in the source code in question). It doesn't suggest anywhere that it should, let alone must, be used to explicitly describe name lookup rules (or we'd need those using directives in nested scopes for
all outer scopes, for example).<span style="color:#1F497D"><o:p></o:p></span></p>
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