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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I think the more usual way for an AsmPrinter to communicate with MCAssembler is via<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">EmitAssemblerFlag, see how MCAF_SubsectionsViaSymbols is handled (for example).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The various streamers should all support this.<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">Note that MipsAsmPrinter is doing the same casting trick.<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>Carter, Jack<br>
<b>Sent:</b> Thursday, January 31, 2013 4:04 PM<br>
<b>To:</b> Chandler Carruth<br>
<b>Cc:</b> Commit Messages and Patches for LLVM<br>
<b>Subject:</b> RE: [llvm] r173885 - This patch implements runtime ARM specific<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"><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black">Chandler,<br>
<br>
Could you elaborate on "there is usually a better pattern to follow"?<br>
<br>
I don't like the casts either and would prefer another way.<br>
<br>
Jack<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black"><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";color:black">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif";color:black"> Chandler Carruth [chandlerc@google.com]<br>
<b>Sent:</b> Thursday, January 31, 2013 3:46 PM<br>
<b>To:</b> Carter, Jack<br>
<b>Cc:</b> Commit Messages and Patches for LLVM<br>
<b>Subject:</b> Re: [llvm] r173885 - This patch implements runtime ARM specific</span><span style="color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"> // Not in an ITBlock to start with.<br>
ITState.CurPosition = ~0U;<br>
+<br>
+ // Set ELF header flags.<br>
+ // FIXME: This should eventually end up somewhere else where more<br>
+ // intelligent flag decisions can be made. For now we are just maintaining<br>
+ // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.<br>
+ MCELFStreamer &MES = static_cast<MCELFStreamer &>(Parser.getStreamer());<br>
+ MES.getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:black">Here, you don't test or check anything, you simply cast to MCELFStreamer, and run. This caused *really* strange bugs. I've fixed it in r174118 to use a proper check on the type of the MCStreamer here, but I would
encourage you to audit some of the other changes in this area to make sure there aren't other instances of this bug.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:black">In general, any use of static_cast<> to move through a dynamic class hierarchy in LLVM is pretty suspect, and something to investigate as there is usually a better pattern to follow.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="color:black"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="color:black">-Chandler<o:p></o:p></span></p>
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