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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">(adding back llvm-dev)<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-left:4.8pt">Is there any standard means to add an extra field to LLVM IR instructions?<o:p></o:p></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"><a name="_MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Your description implies that you are not intending to change the on-disk format, so it's simple:<o:p></o:p></span></a></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">It is a class. Change the source to add a field to it. Use it as you wish.<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>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><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""> its.dipanjan.das@gmail.com [mailto:its.dipanjan.das@gmail.com]
<b>On Behalf Of </b>Dipanjan Das<br>
<b>Sent:</b> Monday, May 08, 2017 1:45 PM<br>
<b>To:</b> Robinson, Paul<br>
<b>Subject:</b> Re: [llvm-dev] Computing unique ID of IR instructions that can be mapped back<o:p></o:p></span></p>
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<p class="MsoNormal">Hi Paul,<o:p></o:p></p>
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<p class="MsoNormal">On 8 May 2017 at 10:50, Robinson, Paul <<a href="mailto:paul.robinson@sony.com" target="_blank">paul.robinson@sony.com</a>> wrote:<o:p></o:p></p>
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Let's say, I walk the file, increment the counter but how'll I assign an ID to an instruction. Because, I need these IDs during an instrumentation phase. In other words, how will the instrumentation phase know what ID has been assigned to a particular instruction?
Because, the instrumentation knows about the instr_ptr (memory address of an instruction) which changes at every run.<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>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><a name="m_3530327484867805471__MailEndCompose"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Two tactics come to mind. First, you can store the
ID directly in the instruction (adding a field to the class) when you assign the IDs.
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">Is there any standard means to add an extra field to LLVM IR instructions?<o:p></o:p></p>
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<p class="MsoNormal"> <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">Second, you can build a map of instr_ptr to ID which you store somewhere that your instrumentation
phase can use to look up the IDs as needed. </span><o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal">As instr_ptr keeps on changing, the mapping isn't not going to work.<o:p></o:p></p>
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<p class="MsoNormal"> <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">Presumably you are not looking to modify the bitcode format itself, as you were worried about consistent
IDs across runs.</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">--paulr</span><o:p></o:p></p>
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<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>Thanks & Regards,<o:p></o:p></p>
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<p class="MsoNormal">Dipanjan<o:p></o:p></p>
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